Bacteriological

Annu Rev Phytopathol, 2000, 38, 365 - 396
NEMATODE PARASITISM GENES; Davis EL et al.; The ability of nematodes to live on plant hosts involves multiple parasitism genes . The most pronounced morphological adaptations of nematodes for plant parasitism include a hollow, protrusible stylet (feeding spear) connected to three enlarged esophageal gland cells that express products that are secreted into plant tissues through the stylet . Reverse genetic and expressed sequence tag (EST) approaches are being used to discover the parasitism genes expressed in nematode esophageal gland cells . Some genes cloned from root-knot (Meloidogyne spp.) and cyst (Heterodera and Globodera spp.) nematodes have homologues reported in genomic analyses of Caenorhabditis elegans and animal-parasitic nematodes . To date, however, the candidate parasitism genes endogenous to the esophageal glands of plant nematodes (such as the ss-1,4-endoglucanases) have their greatest similarity to microbial genes, prompting speculation that genes for plant parasitism by nematodes may have been acquired by horizontal gene transfer.

Annu Rev Phytopathol, 1999, 37, 427 - 446
BIOCONTROL WITHIN THE CONTEXT OF SOIL MICROBIAL COMMUNITIES: A Substrate-Dependent Phenomenon; Hoitink H et al.; Broad spectrum biological control of diseases caused by soilborne plant pathogens such as Pythium, Phytophthora, and Rhizoctonia solani requires the introduction into or presence of edaphic sources of organic nutrients in soil for sustenance of biocontrol agents . The decomposition level of organic matter critically affects the composition of bacterial taxa as well as the populations and activities of biocontrol agents . Competition, antibiosis, parasitism, and systemic induced resistance are all affected . Highly stabilized sources of Sphagnum peat consistently fail to support sustained biological control, even when inoculated with biocontrol agents . Composts, on the other hand, can serve as an ideal food base for biocontrol agents and offer an opportunity to introduce and establish specific biocontrol agents into soils, which in turn leads to sustained biological control based on the activities of microbial communities.

Annu Rev Phytopathol, 1999, 37, 127 - 149
EFFECTS OF PLANTS ON NEMATODE COMMUNITY STRUCTURE; Yeates G; Plant-related inputs provide the resources for nematode communities . Sampling of nematode communities must be on appropriate temporal and spatial scales . Size, feeding types, food or host specificity, and chronology allow over 200 nematode species to coexist in a district . Relationships between nematode functional groups and ecological processes regulating decomposition processes have been found in field experiments . Pulse-labeling experiments have shown root-feeding nematodes to increase the flow of carbon from roots to soil microbial biomass . Soil texture is related to suitability for cropping and affects nematode communities through crop-specific infestations . Nematode diversity tends to be greatest in ecosystems with least disturbance, and bacterial-feeding nematodes make the greatest contribution to the decomposer food web in more intensively managed ecosystems . Indices of the nematode fauna reflect changes in the nematode community; these changes reflect soil and ecological processes . Understanding the role of nematodes in these processes is the key to understanding of the relationship between plants and soil nematode communities.

J Clin Endocrinol Metab, 2001 Nov, 86(11), 5383 - 8
GH strongly affects serum concentrations of mannan-binding lectin: evidence for a new IGF-I independent immunomodulatory effect of GH; Hansen TK et al.; Studies in animals and humans indicate that GH and IGF-I modulate immune function . Recently, it was reported that GH therapy increased the mortality in critically ill patients . The excessive mortality was almost entirely attributable to septic shock or multiorgan failure, suggesting that a GH-induced modulation of immune function was involved . In the present study, we examined whether GH or IGF-I influences the serum concentrations of mannan-binding lectin (MBL) . MBL is a plasma protein of the innate immune system that initiates the complement cascade and activates inflammation after binding to carbohydrate structures on microbial surfaces . We performed a cross-over study of 16 healthy men examined during a control period, and during treatment with either GH or IGF-I for 6 d . The levels of MBL were more than doubled during GH treatment, whereas no changes were observed in the IGF-I group or during the control period (P < 0.001) . IGF-I levels were elevated similarly during treatment with GH and IGF-I . Subsequently, we studied 30 healthy persons and 25 GH-deficient (GHD) patients randomized to treatment with GH or placebo in a double-blinded manner, and further included samples from 23 patients with active acromegaly examined before and after treatment with octreotide or the GH-receptor antagonist pegvisomant for 3 months . Baseline concentrations of MBL were lower in GHD patients and higher in acromegalic patients than in healthy subjects (P < 0.02) . Treatment with GH doubled the MBL concentrations in healthy subjects and almost quadrupled the concentrations in GHD patients; whereas in acromegalic patients, the levels of MBL were reduced to approximately two thirds of the initial values during treatment with octreotide or pegvisomant . Our results demonstrate that treatment with GH, but not IGF-I, significantly increases MBL concentrations . The clinical consequences of this new link between the endocrine and the immune system remain to be elucidated.

J Dent Educ, 2001 Oct, 65(10), 1096 - 101
Salivary enhancement: current status and future therapies; Atkinson JC et al.; Saliva provides the principal protective milieu for teeth by modulating oral microbial ecosystems and reversing the initial phases of caries development . Patients with inadequate salivary function are at increased risk for dental decay . Therefore, it is likely that therapies that increase overall fluid output of these individuals will reverse early carious lesions . The most common causes of salivary dysfunction are medication usage, Sjogren's syndrome, and damage of salivary parenchyma during therapeutic irradiation . For patients with remaining functional acinar tissue, treatment with the parasypathomimetic secretogogues pilocarpine and Cevimeline may provide relief . However, these medications do not benefit all patients . The possibilities of using gene therapy and tissue engineering to develop treatments for those with severe salivary dysfunction are discussed.

Clin Exp Med, 2001 Jun, 1(2), 113 - 9
Bacterial translocation from defunctionalized rat small bowel; Stenback A et al.; Bacterial translocation from the intestine may cause severe infectious complications in a number of clinical situations, including the short bowel syndrome and after small bowel transplantation . The aim of the present study was to develop a simplified model for the study of bacterial translocation from a defunctionalized intestine . An ileal segment from untreated or cyclosporine-treated rats was exteriorized as a Thiry-Vella loop . After 1, 3 . or 7 days, bacterial translocation and distribution of immunocompetent cells were assessed . The data obtained were compared with data from animals subjected to intestinal transplantation . Translocation to the mesenteric lymph nodes was detected in 60% of the Thiry-Vella loop animals on day 1 . in 100% on day 3, and in 83% on day 7: concomitantly, the number of macrophages and T-cells in the mesenteric lymph nodes increased from day I until day 7 . The degree of bacterial translocation on days 3 and 7 in animals with a Thiry-Vella loop was comparable with that observed 7 days after intestinal transplantation . Furthermore, treatment with cyclosporine A enhanced the number of translocating bacteria . In the model presented here bacterial translocation occurs from the small bowel to the mesenteric lymph nodes . The model offers possibilities to study the mechanisms and immunological phenomena associated with microbial translocation.

J Contam Hydrol, 2001 Nov, 52(1-4), 57 - 83
Predicting natural attenuation of xylene in groundwater using a numerical model; Schafer W; The aquifer beneath an abandoned refinery in the Lower Rhine area, Germany, was contaminated with a number of different mineral oil products . Groundwater sampling in the area around the former xylene plant revealed that a xylene plume had developed in the underlying groundwater, and moreover, that there is strong evidence for in situ microbial xylene degradation with oxygen, nitrate, sulfate and ferric iron as electron acceptors . In order to prevent further xylene spreading, three pumping wells extracting contaminated water were installed downgradient of the spill zone . The numerical reactive transport code Transport Biochemisty Chemistry (TBC) was applied to this situation to quantify the relation of microbial degradation to xylene removal by the pumping wells . It could be shown that the unamended in situ degradation was an appreciable xylene removal process that contributed to about one-third to the total xylene removal (degradation plus extraction) . A further objective of the model application was to predict xylene spreading under regional flow conditions, i.e . without operation of the three pumping wells, to consider the possible effects of natural xylene attenuation . To accomplish this, the model calibrated for the situation with operating wells was transferred to the hydraulic situation of regional flow while retaining the parameters of the biochemical model . It turned out that the xylene plume that is expected to develop downgradient of the source area will be limited to an extension of not more than 1000 m . An interesting feature of the simulations results was that xylene degradation under iron-reducing conditions, which was of minor importance for the situation with operating pumping wells, becomes the dominant degradation mechanism under regional flow conditions . Moreover, iron reduction will be the key process in controlling plume evolution . The model application illustrates that multi-species reactive transport models are needed to adequately transfer reactive processes from one hydraulic situation to another, while single species models are not suited for this predictive task.

Chemosphere, 2001 Nov, 45(6-7), 849 - 56
Microbial dechlorination of three PCB congeners in river sediment; Chang BV et al.; We investigated the potential for the anaerobic degradation of three PCB congeners (2,3,5,6-CB, 2,3,4,5-CB, and 2,3,4,5,6-CB) in sediments collected from five monitoring sites along the Keelung River in northern Taiwan . Optimal conditions for congener dechlorination were 30 degrees C and pH 7.0 . Intermediate 2,3,4,5-CB products were identified as 2,3,5-CB, 2,4,5-CB, and 2,5-CB . Intermediate 2,3,4,5,6-CB products were identified as 2,3,5,6-CB, 2,3,6-CB, and 2,5-CB . For 2,3,5,6-CB, intermediate products were identified as 2,3,6-CB and 2,5-CB . Dechlorination rates for PCB congeners were observed as (fastest to slowest): 2, 3, 4-CB > 2, 3, 4, 5-CB > 2, 3, 4, 5, 6-CB > 2, 3, 5, 6-CB > 2, 2', 3, 3', 4, 4'-CB > 2, 2', 4, 4' 6, 6'-CB > 2, 2', 3, 4, 4', 5, 5'-CB > 2, 2', 3, 3', 4, 4', 5, 5'-CB . Rates decreased for mixtures of the eight congeners . Dechlorination rates for the three primary congeners under different reducing conditions occurred in the order of (fastest to slowest): methanogenic condition > sulfate-reducing condition > nitrate-reducing condition . Under methanogenic and sulfate-reducing conditions, dechlorination rates were enhanced by the addition of lactate, pyruvate, or acetate, but delayed by the addition of manganese oxide, or ferric chloride . Under nitrate-reducing condition, dechlorination rates were delayed by the addition of lactate, pyruvate, acetate, manganese oxide or ferric chloride . Treatment with such microbial inhibitors as bromoethanesulfonic acid (BESA) or molybdate revealed that methanogen and sulfate-reducing bacteria were involved in the dechlorination of these three PCB congeners.

Chemosphere, 2001 Nov, 45(6-7), 775 - 82
Mineralisation studies of 14C-labelled metsulfuron-methyl, tribenuron-methyl, chlorsulfuron and thifensulfuron-methyl in one Danish soil and groundwater sediment profile; Andersen SM et al.; Bacterial mineralisation of four sulfonylurea herbicides at 20 microg kg(-1) in a sandy soil from nine different depths in a sandy soil horizon (5-780 cm) was investigated in laboratory studies . Metsulfuron-methyl, chlorsulfuron, and tribenuron-methyl were 14C-labelled in the sulfonamide ring, while thifensulfuron-methyl was labelled in the thiophene ring . The highest mineralised amount in 126 days was observed for metsulfuron-methyl (40%) followed by tribenuron-methyl (25%), and thifensulfuron-methyl (11%) . Chlorsulfuron showed low mineralisation in all the soils tested (<4%) . Mineralisation of the herbicides metsulfuron-methyl and tribenuron-methyl varied according to soil depth (upper profile: 5-70 cm, and lower profile: 165-780 cm) and were proven faster in soil taken from depths 5-7 and 30-35 cm, and slower in depths 45-50 and 70-75 cm . Mineralisation was absent in the lower profile (165-780 cm) . As an indicator of microbial activity bacterial counts were taken at the experimental start; these counts grouped in three levels: highest in the surface layer (5-7 cm), slightly lower in the depths 30-75 cm, and lowest in the lower profile (165-780 cm) . Residual concentrations of metsulfuron-methyl correlated to the accumulated amount mineralised, with high residual concentrations in soil showing low mineralisation . Also chlorsulfuron showed high residual concentrations with increasing depth in the upper profile, but the relatively high dissipation at 30-35 cm and lower one at 45-50 cm could not be related with the lack of mineralisation . This shows that hydrolysis occurs, but mineralisation of the chloro-substituted sulfonamide is restricted . Tribenuron-methyl and thifensulfuron-methyl could not be detected due to interference with other compounds.

J Biol Regul Homeost Agents, 2001 Jul-Sep, 15(3), 257 - 64
Antiviral activity and anergy of gammadeltaT lymphocytes in cord blood and immuno-compromised host; Montesano C et al.; Gammadelta T lymphocytes recognize nonpeptidic microbial antigens without MHC restriction and display both lytic and proliferative responses to human immunodeficiency virus (HIV)-infected cells . This innate recognition involves both T Cell Receptor (TCR) and NK-receptor mediated signalling through non-peptidic metabolites and HLA class I down-regulation . We observed that HLA-masking and nonpeptidic phosphoantigens induce the expression of CD25 and CD69 activation markers on the surface of gammadelta T cells . Interestingly, CD94+ cell depletion by magnetic beads showed that the expression of this antigen is essential for Vdelta2 T cell activation by HLA-masking . Moreover, both phosphoantigen-stimulation and in vitro HIV infection resulted in marked Vgamma9Vdelta2 T cell expansion, whereas HLA-masking was unable to induce proliferative responses . Finally, we observed a relevant hyporesponsiveness to non-peptidic antigens in HIV-infected persons and in cord blood cells from healthy donors when compared to adult PBMC from uninfected donors . Altogether, the reduced ability to naturally recognize the infected cells may contribute to HIV-disease progression and may facilitate maternal transmission of HIV infections.

J Biol Regul Homeost Agents, 2001 Jul-Sep, 15(3), 249 - 56
Immunity to glycolipid antigens in microbial infections; De Libero G et al.; T cells recognize ligands of different chemical structures . Recently, it has become clear that also self glycosphingolipids and bacterial lipoglycans may act as T cell stimulatory ligands . This type of antigen recognition is restricted by the non-polymorphic CD1 molecules, which have a structure resembling that of classical MHC molecules . Glycolipids insert their hydrophobic lipid tails in two pockets below the antigen-binding groove and position their hydrophilic heads on the external part of CD1 molecules . TCR interacts with these carbohydrates and discriminates their structural variations . Glycolipid-specific T cells may provide protection during bacterial and parasite infection probably with different mechanisms: by secreting pro-inflammatory lymphokines, by the direct killing of infected target cells, and by helping specific B cells in Ig production . Lipoglycans represent excellent candidates for new anti-microbial vaccines due to their wide distribution in the microbial world and their structural composition which does not change and thus cannot give rise to escape mutants . Moreover, these vaccines might induce anti-microbial protective T cell responses in the whole population due to the non-polymorphic nature of CD1 presenting molecules.

Mikrobiol Z, 2001 Jul-Aug, 63(4), 15 - 9
{Peculiarities of structure-function organization of microbial groups of soil contaminated by cement dust}; Stefurak VP; Long-term contamination of the forest soil by the cement dust leads to disturbances of stability of natural microbial groups, changes their quantitative and qualitative composition, results in substitution of some microbial associations by other ones . The intensive contamination of the soil by the effluents of cement integrated works, inhibits the intensity of nitrogen fixation processes and decay of the forest litter, development of micromycetes, results in the decrease of the length of mycelium and its biomass.

Vet Clin North Am Food Anim Pract, 2001 Nov, 17(3), 621 - 33, viii
Immunomodulators for prevention and treatment of infectious diseases in food-producing animals; Blecha F; The goal of immunomodulation in food-producing animals is to regulate immunity for the benefit of the animal and production efficiency . Immunomodulators are substances that exert this control and include cytokines, pharmaceuticals, microbial products, nutraceuticals, and traditional medicinal plants . Although treatment and prevention of infectious diseases are the most common reasons to use immunomodulators, other conditions, such as amelioration of stress-induced immunosuppression, maturation of the neonate's developing immune response, and strategies to reduce the metabolic cost of eliciting an immune response also are well suited for immunomodulation . Continued discovery of new immune regulators and increased understanding of immunity in food-producing animals will ensure new opportunities for the use of immunomodulators in food-producing animals.

Vet Clin North Am Food Anim Pract, 2001 Nov, 17(3), 585 - 97, vii
New technology for improved vaccine safety and efficacy; Roth JA et al.; Nearly all of the 2000 vaccines presently licensed by the US Department of Agriculture for veterinary use in the United States are conventional vaccines containing either killed or modified live whole bacteria or viruses . Recent advances in molecular biology, immunology, microbiology, and genetics and in understanding microbial pathogenesis have led to the development of a wide variety of new approaches for developing safer and more effective vaccines . This article briefly describes these new technologies and their potential advantages and disadvantages as compared with conventional killed and modified live vaccines.

J Allergy Clin Immunol, 2001 Nov, 108(5), 847 - 54
Exposure to endotoxin decreases the risk of atopic eczema in infancy: a cohort study; Gehring U et al.; BACKGROUND: Previous studies have shown a protective effect of early exposure to cats and dogs on the development of atopic eczema, asthma, allergic rhinitis, and atopic sensitization in later life . In particular, a higher microbial exposure to endotoxin in early childhood might contribute to this effect . OBJECTIVE: We examined the associations between bacterial endotoxin in house dust and atopic eczema, infections, and wheezing during the first year of life in an ongoing birth cohort study (LISA) . METHODS: Data of 1884 term and normal-weight neonates with complete information on exposure to biocontaminants and confounding variables were analyzed . House dust from the mothers' and the children's mattresses was sampled 3 months after birth . Endotoxin content was quantified by using a chromogenic kinetic limulus amoebocyte lysate test . RESULTS: During the first 6 months of life, the risk of atopic eczema was significantly decreased by endotoxin exposure in dust from mothers' mattresses in the fifth quintile (odds ratio {OR}, 0.50; 95% CI, 0.28-0.88), whereas the risk was increased for respiratory infections (OR, 1.69; 95% CI, 1.25-2.28) and cough with respiratory infection, bronchitis, or both (OR, 1.73; 95% CI, 1.28-2.33) . The risk of wheezing was also significantly increased during the first 6 months of life (OR, 2.37; 95% CI, 1.40-4.03) . For the entire first year of life, these associations attenuated, except for the risk of wheezing, which remained significant (OR, 1.60; 95% CI, 1.10-2.30) . CONCLUSION: Our findings support the hygiene hypothesis that exposure to high concentrations of endotoxin very early in life might protect against the development of atopic eczema within the first 6 months of life, along with an increased prevalence of nonspecific respiratory diseases.

J Allergy Clin Immunol, 2001 Nov, 108(5), 688 - 96
Multistep navigation of Langerhans/dendritic cells in and out of the skin; Jakob T et al.; Langerhans cells (LCs) are specialized antigen-presenting cells that reside in the epidermis as sentinels of the immune system . LCs constantly monitor the epidermal microenvironment by taking up antigen and processing it into fragments that can be recognized by cells of the adaptive immune response . Because of their unique migratory ability, LCs can transport antigen from the epidermis to regional lymph nodes, where they can initiate systemic immune responses . The mechanisms of LC trafficking thus seem to be of particular relevance for the induction and maintenance of cutaneous immunity . LCs or their putative precursors express surface molecules that allow them to home to skin and localize in the epidermis for prolonged periods of time . Tissue injury, microbial infection, and other perturbants of epidermal homeostasis (eg, contact allergens) provide danger signals, leading to a local production of proinflammatory cytokines that induce LC mobilization to the lymphoid tissue . At the same time, signals are generated that recruit LC precursors into the skin to maintain the epidermal LC population . Distinct pairs of chemokines and their receptors control the migration from blood to epidermis and from there to the regional lymphatics . In addition, trafficking is controlled at the level of cell adhesion, where LCs downregulate some adhesion molecules to exit the epidermis and upregulate others to migrate across the extracellular matrix and home to T-cell areas of regional lymphoid tissue . The improved understanding of mechanisms that regulate LC trafficking might offer new opportunities for therapeutic interventions to suppress, stimulate, or deviate cutaneous immune responses.

J Biotechnol, 2002 Jan 18, 92(3), 259 - 66
Synthesis of a novel macrolactone by lipase-catalyzed intra-esterification of hydroxy-fatty acid in organic media; Gargouri M et al.; The unsaturations and groups bound to the ring and to the lateral chain of lactones give a large diversity in this class of molecules . In this work we produced enzymatically a macrolactone in organic media . The substrate used was a hydroxy-fatty acid: (+)-coriolic acid and the enzymes tested were free or immobilized microbial lipases . The immobilized lipase from Candida antarctica seems to be the most adequate catalyst offering a high reaction yield . The intra-esterification was studied as a function of temperature and type of solvent . Higher yields were obtained when using diisopropyl-ether at 35 degrees C . This reaction, involving an alcohol group on an internal position on the carbon chain of the substrate hydroxy-acid, produces an original lactone: 13S-octadeca-(9Z,11E)-dienolide . The product was purified and characterized using (1)H nuclear magnetic resonance spectroscopy, mass spectrometry and infrared spectroscopy.

Respir Res, 2001, 2(3), 129 - 32 Epub 2001 Apr 02.
The coming-of-age of the hygiene hypothesis; Martinez FD; The hygiene hypothesis, as originally proposed, postulated an inverse relation between the incidence of infectious diseases in early life and the subsequent development of allergies and asthma . New evidence from epidemiological, biological and genetic studies has significantly enlarged the scope of the hypothesis . It now appears probable that environmental 'danger' signals regulate the pattern of immune responses in early life . Microbial burden in general, and not any single acute infectious illness, is the main source of these signals . The latter interact with a sensitive and complex receptor system, and genetic variations in this receptor system may be an important determinant of inherited susceptibility to asthma and allergies.

J Anim Physiol Anim Nutr (Berl), 2001 Feb, 85(1-2), 9 - 21
Small intestinal digestibility of microbial and endogenous amino acids in dairy cows; Larsen M et al.; The small intestinal digestibility of microbial amino acids and the apparent re-absorption of endogenous amino acids were estimated in three ruminal, duodenal and ileal fistulated lactating dairy cows . The cows were assigned to a 3 x 3 Latin square and fed diets low in amino acids, composed of straw, starch, molasses and urea . The treatments were three straw to concentrate ratios . The digestibilities and re-absorptions were estimated from duodenal and ileal flows of amino acids from feed, microbial and endogenous sources . The duodenal distribution of amino acids between different origins was determined by the difference method and by the amino acid profile method . The ileal distribution was estimated by a simple method where the feed fraction was estimated by the mobile bag method, the endogenous fraction as the water soluble fraction and the microbial fraction as the rest . In ileal samples, 8.0 +/- 1.1, 52.2 +/- 2.9 and 39.8 +/- 2.6% of total amino acid nitrogen (AAN) were of feed, microbial and endogenous origin, respectively, compared with 5.1 +/- 0.9, 61.6 +/- 6.6 and 32.7 +/- 6.9% in duodenal samples . The small intestinal digestibility of microbial AAN was estimated to be 75.1 +/- 1.8% and the apparent re-absorption of endogenous AAN to be 62.3 +/- 11.1%.

Phytochemistry, 2001 Nov, 58(6), 929 - 33
Biocatalytic chlorination of aromatic hydrocarbons by chloroperoxidase of Caldariomyces fumago; Vazquez-Duhalt R et al.; Chloroperoxidase from Caldariomyces fumago was able to chlorinate 17 of 20 aromatic hydrocarbons assayed in the presence of hydrogen peroxide and chloride ions . Reaction rates varied from 0.6 min(-1) for naphthalene to 758 min(-1) for 9-methylanthracene . Mono-, di- and tri-chlorinated compounds were obtained from the chloroperoxidase-mediated reaction on aromatic compounds . Dichloroacenaphthene, trichloroacenaphthene, 9,10-dichloroanthracene, chloropyrene, dichloropyrene, dichlorobiphenylene and trichlorobiphenylene were identified by mass spectral analyses as products from acenaphthene, anthracene, pyrene and biophenylene respectively . Polycyclic aromatic hydrocarbons with 5 and 6 aromatic rings were also substrates for the chloroperoxidase reaction . The importance of the microbial chlorination of aromatic pollutants and its potential environmental impact are discussed.

Can J Microbiol, 2001 Sep, 47(9), 877 - 82
Rapid identification of Escherichia coli microcin J25 producing strains using polymerase chain reaction and colony blot hybridization; Duarte M et al.; To screen, isolate, and characterize bacterial populations producing microcin J25, we report here two rapid, reliable, and sensitive methods, using polymerase chain reaction and colony blot hybridization with a digoxigenin-labelled probe . A sample of 26 Escherichia coli strains isolated from poultry intestinal contents was evaluated to detect the sequence of mcjA, the gene encoding the MccJ25 precursor . The two molecular techniques were compared with the commonly used cross-immunity tests . They generate accurate data with no obvious cross-reactions with other microcins . The results display that the producers of MccJ25 were widely distributed in the poultry intestinal habitat . The applications of these molecular methods will be useful in future studies of microcinogenic populations, and thus contribute to understand the relationships within the complex intestinal microbial ecosystem.

Curr Opin Genet Dev, 2001 Dec, 11(6), 620 - 6
Detection of lateral gene transfer among microbial genomes; Ragan MA; An increasingly comprehensive assessment is being developed of the extent and potential significance of lateral gene transfer among microbial genomes . Genomic sequences can be identified as being of putatively lateral origin by their unexpected phyletic distribution, atypical sequence composition, differential presence or absence in closely related genomes, or incongruent phylogenetic trees . These complementary approaches sometimes yield inconsistent results . Not only more data but also quantitative models and simulations are needed urgently.

FEMS Microbiol Lett, 2001 Oct 16, 204(1), 1 - 7
Predicting the emergence of resistance to antifungal drugs; Cowen LE; The emergence of antifungal drug resistance is inevitable . Here I discuss antibiotic resistance in the context of the adaptive potential of fungi and I propose an approach to predicting the evolution of antifungal resistance using experimental evolution of DNA sequences and microbial populations . Prediction is based on determination of evolutionary potential at two levels, the gene and the genome . At the level of the gene, evolutionary potential depends on the sequence space of candidate resistance genes defined by the fitness effects of all possible mutations in all possible combinations . At the level of the genome, evolutionary potential depends on the adaptive landscape defined by the fitness effects of all possible interactions among alleles constituting the genotype.

Chemosphere, 2001 Nov, 45(4-5), 445 - 51
Microbial ecotoxicity and mutagenicity of 1-hydroxypyrene and its photoproducts; Hwang HM et al.; 1-Hydroxypyrene (1-HP) is a carcinogenic and slightly water-soluble polycyclic aromatic hydrocarbon . Ecotoxicity and mutagenicity of 1-HP and its photoproducts, and the effect of Mn2+ and Cu2+ on their mutagenicity were measured with microbial assay in this study . The assay includes spread plate counting, direct counting, microbial mineralization of 14C-UL-D-glucose and Mutatox Test . At the concentration examined (0.8 microM), the photoproducts (after 1.5 h solar irradiation) of 1-HP inhibited microbial glucose mineralization activity (by 64%) after microbial assemblages of a local reservoir site were exposed for 1 day . However, heterotrophic bacteria were able to utilize 1-HP photoproducts as the growth substrates and increase viability counts by up to 4.75-folds . 1-HP exhibited positive response to Mutatox Test in both direct medium and S-9 medium, with the lowest observable effective concentration of 0.625 microM in the test with direct medium . After photolysis, 1-HP decreased its mutagenicity . Mn2+ (312.5 microM-5 mM) and Cu2+ (6.25-100 microM) themselves are not mutagenic . However, addition of the metal ions before or after photolysis modifies the light readings of 1-HP during the test . Therefore, presence of metal ions could affect the genotoxicity of 1-HP in aquatic environments, depending on timing of the addition.

Adv Immunol, 2001, 79, 55 - 92
Regulation of interleukin-12 production in antigen-presenting cells; Ma X et al.; Interleukin-12 is a cytokine produced by antigen-presenting cells that is essential for host defense against intracellular microbial infection and control of malignancy by virtue of its ability to stimulate both innate and adaptive immune effector cells . The immune potentiating capacity of IL-12 and its mandatory requirement in host defense predispose it to rigorous regulation . The time, localization, and magnitude of IL-12 production during an immune response strongly influence the type, extent, and, ultimately, the fate of the response . Disturbance of this evolutionarily maintained "balance of power" frequently leads to immunologic disorders . This article reviews the intricate pathways that have been uncovered in which IL-12 production is modulated by numerous pathogens and immunological regulators . The understanding of IL-12 regulation in physiological settings will undoubtedly lend valuable support to the design of therapeutic applications of IL-12.

Appl Environ Microbiol, 2001 Nov, 67(11), 5343 - 8
Diversity and detection of nitrate assimilation genes in marine bacteria; Allen AE et al.; A PCR approach was used to construct a database of nasA genes (called narB genes in cyanobacteria) and to detect the genetic potential for heterotrophic bacterial nitrate utilization in marine environments . A nasA-specific PCR primer set that could be used to selectively amplify the nasA gene from heterotrophic bacteria was designed . Using seawater DNA extracts obtained from microbial communities in the South Atlantic Bight, the Barents Sea, and the North Pacific Gyre, we PCR amplified and sequenced nasA genes . Our results indicate that several groups of heterotrophic bacterial nasA genes are common and widely distributed in oceanic environments.

Biosens Bioelectron, 2001 Dec, 16(9-12), 695 - 9
The extremely rapid oligonucleotide hybridization and high throughput detection of microbial gene sequences using fluorescence polarization; Tsuruoka M et al.; The hybridization of oligonucleotide sequences complementary to the genes of Shiga toxins (verotoxins) types 1 and 2 of enterohaemorrhagic Escherichia coli (EHEC) and human hepatitis C virus (HCV) was monitored using fluorescence polarization under the reaction condition of high salt concentration (0.8 M NaCl), which was optimized to obtain a higher rate of hybridization . The time courses of hybridization of fluorescently labeled oligomers (probe DNAs) with the amplified DNA or RNA of the genes were recorded . Two methods, the asymmetric PCR and NASBA, were used to amplify the genetic DNA of Shiga toxins and that of RNA in HCV, respectively . Probe DNA sequences were designed which hybridized extremely rapidly with amplicons of the genes of Shiga toxins types 1 and 2 and that of HCV . In the cases using the three different DNA probes, the hybridization was 90% complete in about 1 min, considerably faster than that of the 3 min reported previously . The rapidity of this hybridization could not be explained by the melting temperature or the G+C content of the probe sequences but its relationship with high order structure of the single stranded DNA or RNA of the amplicons in the solution was strongly suggested.

J Am Diet Assoc, 2001 Oct, 101(10), 1194 - 8
A survey of the use of low microbial diets in pediatric bone marrow transplant programs; French MR et al.; A survey was used to determine the use of low microbial diets for pediatric bone marrow transplantation patients at hospitals in Canada and the northwestern United States . Five out of 7 hospitals responding to the survey provided a low microbial diet to this population to reduce the potential risk posed by food pathogens . Two hospitals prepared their low microbial diet in a separate kitchen using aseptic techniques . One hospital provided a diet consisting of well-cooked foods or foods containing a minimum number of pathogen-forming units . Another hospital focused on safe food-handling guidelines, avoiding foods associated with foodborne illness . A final hospital reported using a modified house diet that excluded fresh fruits and vegetables . Various guidelines were used to determine when to initiate and discontinue the low microbial diet . These guidelines included criteria such as a specific day relative to transplantation and a patient's absolute neutrophil count . Results indicate that most hospitals acknowledge the potential for food to cause infection in patients with compromised immune systems by imposing dietary restrictions to limit pathogen exposure.

Int Immunol, 2001 Nov, 13(11), 1391 - 404
Lipopolysaccharide and CpG DNA synergize for tumor necrosis factor-alpha production through activation of NF-kappaB; Yi AK et al.; Unmethylated CpG motifs in bacterial DNA (CpG DNA) activate host innate immune responses synergistically with some other microbial products, such as endotoxins, and may contribute to disease pathogenesis through excessive production of proinflammatory cytokines . Because monocyte-derived tumor necrosis factor (TNF)-alpha is an important mediator of disease, we investigated whether CpG DNA and lipopolysaccharide (LPS) synergize for inducing TNF-alpha biosynthesis . CpG DNA and LPS synergistically induce TNF-alpha production in RAW264.7 cells and J774 cells through activation of NF-kappaB . Furthermore, transient transfection with a super-repressive mutant of IkappaBalpha (IkappaBalpha-AA) demonstrated that NF-kappaB plays a critical role in CpG DNA-mediated TNF-alpha expression . Like NF-kappaB activation, CpG DNA-induced activation of mitogen-activated protein kinases (MAPK) regulates TNF-alpha production . Both extracellular receptor kinase (ERK) and p38 can regulate TNF-alpha gene transcription induced by CpG DNA . Although CpG DNA at the higher concentration slightly enhanced LPS-mediated phosphorylation of ERK, it did not alter the LPS-mediated activation of c-Jun N-terminal kinase and p38 . In addition, CpG DNA showed little or no enhancement of LPS-mediated AP-1 activation . These results suggest that CpG DNA- and LPS-mediated signals converge at or above the level of NF-kappaB and ERK, and that there are distinct, as well as common, signaling pathways which are utilized by both CpG DNA and LPS for activating various transcription factors and MAPK.

Inorg Chem, 1999 Feb 8, 38(3), 449 - 454
Electrochemical Behavior of the Fe(III) Complexes of the Cyclic Hydroxamate Siderophores Alcaligin and Desferrioxamine E; Spasojevic I et al.; The redox behavior of Fe(III) complexes of the cyclic hydroxamate siderophores alcaligin and desferrioxamine E was investigated by cyclic voltammetry . The limiting, pH independent redox potential (E(1/2) vs NHE) is -446 mV for alcaligin above pH 9 and -477 mV for ferrioxamine E above pH 7.5 . At lower pH values, the redox potential for both complexes shifts positive, with a loss of voltammetric reversibility which is interpreted to be the consequence of a secondary dissociation of Fe(II) from the reduced form of the complexes . These observations are of biological importance, since they suggest the possibility of a reductive mechanism in microbial cells which utilize these siderophores to acquire Fe . For comparison purposes, cyclic voltammograms were obtained for Fe(III) complexes with trihydroxamic acids of cyclic (ferrioxamine E) and linear (ferrioxamine B) structures, with dihydroxamic acids of cyclic (alcaligin) and linear (rhodotorulic and sebacic acids) structures, and with monohydroxamic acids (acetohydroxamic and N-methylacetohydroxamic acids) at identical conditions . The observed redox potentials allow us to estimate the overall stability constants for fully coordinated Fe(II) complexes as log beta(II)(Fe(2)alcaligin(3)) = 24.6 and log beta(II)(ferrioxamine E) = 12.1 . A linear correlation between E(1/2) and pM was found, and the basis for this relationship is discussed in terms of structural (denticity and cyclic/acyclic) and electronic differences among the {alkyl-NOH-CO-alkyl} type of hydroxamic acid ligands studied.

Contraception, 2001 Jun, 63(6), 335 - 42
Effect of vaginally administered (Ala(8,13,18))-magainin II amide on the morphology of implantation stage endometrium in the rhesus monkey (Macaca mulatta); Ghosh D et al.; Intravaginal administration of an anti-microbial agent, (Ala(8,13,18))-magainin II amide, during blastocyst implantation inhibits pregnancy establishment in a dose-related manner in the rhesus monkey (Macaca mulatta) . In the present study, mated female rhesus monkeys were vaginally inserted with tampons containing vehicle (Group 1; n = 5) and test agent (magainin, 0.5 mg/animal; Group 2; n = 6) on cycle day 20 . Endometrial tissue samples were collected on Cycle Day 24 from all monkeys and processed for morphometric and ultrastructural analysis . Concentrations of estradiol-17beta, progesterone, and chorionic gonadotrophin in peripheral circulation were determined, which revealed that two monkeys in Group 1 were pregnant while no animals were pregnant in Group 2 . Endometrial morphology, however, revealed histologic evidence of pregnancy in three out of the six magainin-treated animals . It appears that intra-vaginal administration of magainin II amide had a marginal effect on the implantation stage endometrium and the initiation of the implantation process in the rhesus monkey.

Inorg Chem, 1998 Dec 28, 37(26), 6630 - 6637
A Preorganized Siderophore: Thermodynamic and Structural Characterization of Alcaligin and Bisucaberin, Microbial Macrocyclic Dihydroxamate Chelating Agents(1); Hou Z et al.; The iron coordination chemistry of two macrocyclic dihydroxamate siderophores, alcaligin (AG) and bisucaberin (BR), has been investigated thermodynamically and structurally . Alcaligin is a siderophore of freshwater bacteria as well as mammalian pathogens, including the bacterium that causes whooping cough in humans, while bisucaberin, a structural analogue of alcaligin, is produced by marine bacteria . Both alcaligin and bisucaberin form 1:1 ferric complexes (FeL(+)) in acidic conditions and 2:3 ferric complexes (Fe(2)L(3)) at and above neutral pH . The stability constants of these macrocyclic dihydroxamate siderophores differ significantly from that of rhodotorulic acid (RA), a linear dihydroxamate siderophore . Notably, K(FeL) of alcaligin is 32 times greater than that of rhodotorulic acid, while the subsequent stepwise formation constant for Fe(2)L(3) is 3 times less . The Fe(III) complexes of alcaligin are stereospecific; the absolute configuration of the Fe(2)L(3) complex (circular dichroism and X-ray structure) is Lambda . The structure of the Fe(2)L(3) alcaligin complex is a topological alternative to the triple-helicate structure of the rhodotorulic complex Fe(2)(RA)(3) . The structures of the free ligand and the bisbidentate ligand in the FeL complex are essentially identical, indicating that alcaligin is highly preorganized for metal ion binding . This explains the difference in K(FeL) between alcaligin and rhodotorulic acid, as well as explaining the monobridged topology of the Fe(2)L(3) alcaligin complex . The protonation constants (log K(a1) and log K(a2)) are 9.42(5) and 8.61(1) for alcaligin and 9.49(2) and 8.76(3) for bisucaberin . The stepwise formation constants of the Fe(III) complexes (log K(ML) and log K(M)()2(L)()3) are 23.5(2) and 17.7(2) for alcaligin and 23.5(5) and 17.2(5) for bisucaberin . The overall formation constants (log beta(230)) of alcaligin and bisucaberin are 64.7(1) and 64.3(1) . The solution chemistry of Fe(III) and alcaligin was further investigated at a lower ligand to metal ratio (1:1) . At high pH, a novel 2:2 ferric bis-&mgr;-oxo-bridged complex of alcalagin forms (Fe(2)L(2)O(2)(2)(-)) with a log beta(22)(-)(4) of 16.7(2) . This species exhibits behavior consistent with an iron bis-&mgr;-oxo complex, including antiferromagnetic coupling . Crystal data: Fe(2)(AG)(3).25H(2)O crystallizes in the orthorhombic space group P2(1)2(1)2(1) with a =13.3374(4) A, b = 16.1879(5) A, c = 37.886(1) A, V = 8179.7(4), Z = 4 . For 5512 reflections with F(o)(2) > 3sigma(F(o)(2)) the final R (R(w)) = 0.053(0.068).

Cytokine, 2001 Oct 7, 16(1), 1 - 9
Differential response of the murine IL-12 p35 gene to lipopolysaccharide compared with interferon-gamma and CD40 ligation; Vaidyanathan H et al.; Expression of the heterodimeric cytokine interleukin-(IL-)12 is induced by pattern recognition receptors responding to microbial stimuli such as lipopolysaccharide (LPS) and products of the immune system such as interferon-gamma (IFN-gamma) and CD40L . The formation of bioactive IL-12 requires equimolar synthesis of p35 and p40 subunits . However, p35 expression limits the amount of IL-12 formed . Transcription of the gene for the p35 subunit of IL-12 initiates within the first exon, an alternate first exon (exon 1a), or second exon . Here we show that LPS and IFN-gamma/CD40 ligation increase the amount of total p35 mRNA in splenic adherent cells (SAC) to a similar extent . However, the exon 1 transcript was a smaller fraction of total p35 mRNA in IFN-gamma/CD40-stimulated cells than in unstimulated or LPS-stimulated cells . Despite comparable levels of total p35 mRNA, LPS-induced p35 exon 1 transcripts led to significantly more bioactive IL-12 from SAC than IFN-gamma/CD40-induced exon 1a/exon 2 transcripts as measured by ELISA . The data suggest that LPS-inducible p35 synthesis from exon 1 p35 transcripts leads to greater amount of bioactive IL-12 than IFN-gamma/CD40-induced p35 expression from alternate p35 exon 1a/exon 2 transcripts .

J Dent Res, 2001 Aug, 80(8), 1695 - 9
Polymorphisms of the interleukin-1 gene family, oral microbial pathogens, and smoking in adult periodontitis; Laine ML et al.; Interleukin (IL)-1alpha, IL-1beta, and IL-1ra contribute to regulation of the inflammatory response in periodontal tissues . We aimed to investigate the distribution of polymorphisms in the IL-1 gene family among periodontitis patients and controls, taking into account smoking and microbiology as additional variables . Fifty-three non-smoking and 52 smoking patients with severe adult periodontitis and 53 controls were genotyped for bi-allelic IL-1A(-889), IL-1B(-3954), and a penta-allelic 86-bp VNTR IL-1RN gene polymorphisms . The presence of Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans was established by culture techniques . We found a higher frequency of allele 2 carriage in IL-1A, IL-1B, and IL-1RN in periodontitis patients who were non-smokers and in whom P . gingivalis and A . actinomycetemcomitans could not be detected (42.1% vs . 11.3% in controls; P = 0.0068; OR 5.7, 95% CI: 1.6-19.8) . Our results provide evidence that polymorphisms in genes of the IL-1 family are associated with severe adult periodontitis in the absence of other risk factors tested in this patient population.

Scand J Infect Dis, 2001, 33(9), 673 - 80
Molecular diagnosis of infective endocarditis--a new Duke's criterion; Millar B et al.; The molecular approach of PCR amplification of specific gene targets and universal loci for bacteria (16S rRNA) and fungi (18S, 28S and 5.8S rRNA) and subsequent sequencing was used to identify the possible causal microbial agent(s) in blood culture (47 patients) and heart valve material (30 patients) from patients with suspected infective endocarditis (IE) . Culture and molecular results were analysed with respect to the patients' clinical background and the Duke Criteria . The findings demonstrated that: (i) all patients who were definite or possible cases were positive by PCR, even patients whose blood culture and valve material were culture-negative; and (ii) all patients who were rejected as having IE were also negative by PCR, with the exception of 1 patient who had bacteraemia from another source and 5 patients whose blood culture material was believed to contain an environmental contaminant . Direct molecular identification of the aetiological agents responsible for IE from blood culture material may enable specific treatment to commence at an earlier stage of the disease and hence reduce the need for valve replacement . Such a molecular approach may aid in the diagnosis of IE and should therefore be included as an additional major criterion in the Duke's classification scheme.

Biotechnol Bioeng, 2001 Nov 20, 75(4), 469 - 74
Using ATP bioluminescence technique for monitoring microbial activity in sludge; Chu CP et al.; This study demonstrates, for the first time, that the presence of suspended solids in waste-activated sludge interferes with adenosine triphosphate (ATP) bioluminescence tests . The sludge subject to acid/alkaline treatment represented the test sample . Without consideration of the effect of solid concentrations, one would erroneously estimate the density levels of heterotrophic bacteria in the sludge using ATP data . A light blockage model was proposed to evaluate the luminescence reading without the interference of suspended solids .

Respir Res, 2000, 1(2), 67 - 72 Epub 2000 Aug 15.
Nitric oxide: a pro-inflammatory mediator in lung disease?
van der Vliet A, Eiserich JP, Cross CE.
Inflammatory diseases of the respiratory tract are commonly associated with elevated production of nitric oxide (NO*) and increased indices of NO* -dependent oxidative stress . Although NO* is known to have anti-microbial, anti-inflammatory and anti-oxidant properties, various lines of evidence support the contribution of NO* to lung injury in several disease models . On the basis of biochemical evidence, it is often presumed that such NO* -dependent oxidations are due to the formation of the oxidant peroxynitrite, although alternative mechanisms involving the phagocyte-derived heme proteins myeloperoxidase and eosinophil peroxidase might be operative during conditions of inflammation . Because of the overwhelming literature on NO* generation and activities in the respiratory tract, it would be beyond the scope of this commentary to review this area comprehensively . Instead, it focuses on recent evidence and concepts of the presumed contribution of NO* to inflammatory diseases of the lung.

J Org Chem, 1996 Apr 19, 61(8), 2845 - 2852
Total Synthesis of Natural PI-091, a New Platelet Aggregation Inhibitor of Microbial Origin; Shiraki R et al.; The total synthesis of a new platelet aggregation-inhibiting gamma-lactam PI-091 (1) gave a 1:1 diastereomeric mixture at the gamma-ketal carbon . The high-yielding aldol reaction of an appropriately protected 1,3,4-trihydroxy-4-methyldecan-2-one 42, prepared from D-glucose, with the kinetically generated enolate of 3-methyl-2-butanone provided 43 . The resulting diastereomeric mixture of the aldol adduct 43 was converted to a 2,4-alkylated furan 45 via an intramolecular ketalization followed by dehydration . The addition of a singlet oxygen to the alpha-trimethylsilylated furan 48derived from 45 under photochemical conditions efficiently provided an alpha,gamma-dialkylated gamma-hydroxy gamma-lactone 47 . The transformation of methyl ketal 52 prepared from 47 into gamma-hydroxy gamma-lactam 53 was achieved by exposure to liquid ammonia in MeOH . The total synthesis of 1 was achieved from 52 through the Dess-Martin periodinane oxidation of the secondary hydroxy group in the side chain . The present total synthesis revealed that the stereogenic carbon center in the side chain in natural 1 is S.

Inorg Chem, 1996 Mar 13, 35(6), 1659 - 1666
Chemical and Biological Studies of Dichloro(2-((dimethylamino)methyl)phenyl)gold(III); Parish RV et al.; Several new organogold(III) derivatives of the type {AuX(2)(damp)} (damp = o-C(6)H(4)CH(2)NMe(2)) have been prepared {X = CN, SCN, dtc, or X(2) = tm; dtc = R(2)NCS(2) (R = Me (dmtc) or Et (detc)); tm = SCH(CO(2))CH(2)CO(2)Na} together with {AuCl(tpca)(damp)}Cl (tpca = o-Ph(2)PC(6)H(4)CO(2)H), {Au(dtc)(damp)}Y (Y = Cl, BPh(4)) and K{Au(CN)(3)(damp)} . The (13)C NMR spectra of these and previous derivatives have been fully assigned . In {Au(dtc)(2)(damp)} and K{Au(CN)(3)(damp)}, the damp ligand is coordinated only through carbon, as shown by X-ray crystallography and/or NMR . {Au(detc)(2)(damp)} has space group C2/c, with a = 29.884(4) A, b = 13.446(2) A, c = 12.401(2) A, beta = 99.45(3)(o), V = 4915 A(3), Z = 8, and R = 0.057 for 1918 reflections . The damp and one detc ligand are monodentate, the other detc is bidentate; in solution, the complex shows dynamic behavior, with the detc ligands appearing equivalent . The crystal structure of {Au(dmtc)(damp)}BPh(4) {Pna2(1), a = 26.149(5) A, b = 11.250(2) A, c = 11.921(2) A, V = 3507 A(3), Z = 4, R = 0.073, 1772 reflections} shows both ligands to be bidentate in the cation, but the two Au-S distances are nonequivalent . The crystal structure of {Au(tm)(damp)} has also been determined {P2(1)/n, a = 18.267(7) A, b = 9.618(3) A, c = 18.938(4) A, beta = 113.45(3)(o), V = 3053 A(3), Z = 8, R = 0.079, 1389 reflections} . The tm is bound through sulfur and the carboxyl group which allows five-membered ring formation . In all three structures, the trans-influence of the sigma-bonded aryl group is apparent . {AuCl(2)(damp)} has been tested in vitroagainst a range of microbial strains and several human tumor lines, where it displays differential cytotoxicity similar to that of cisplatin . Against the ZR-75-1 human tumor xenograft, both {AuCl(2)(damp)} and cisplatin showed limited activity.

Nature . 1984 Dec 20-27;312(5996):686.
Genetic pesticides: Monsanto goes ahead with trials; Beardsley T; KIE: The Monsanto Company will soon notify the Environmental Protection Agency (EPA) that it plans to conduct the first field test of a genetically-engineered microbial pesticide, thereby becoming the first company to break with the convention whereby private corporations have voluntarily sought approval for genetic engineering experiments from the Recombinant DNA Advisory Committee (RAC) of the National Institutes of Health (NIH) . It is assumed that Monsanto's decision was influenced by a preliminary legal injunction blocking NIH approval of such field trials without a formal environmental assessment . EPA will allow tests, after 90 days' notice, if it raises no objections to the protocol . Although EPA will not formally call on RAC to examine the protocol, an agency spokesperson said there is "total agreement" between EPA and RAC on what data must be included .

Crit Rev Immunol, 2001, 21(1-3), 121 - 31
Peripheral nonresponsiveness to orally administered soluble protein antigens; Nagler-Anderson C et al.; The presentation of soluble model food antigens to the intestinal immune system typically induces antigen-specific systemic nonresponsiveness . Yet, the gut-associated lymphoid tissue (GALT) must launch an effective attack against potentially invasive pathogens even as it avoids mounting a response to innocuous food antigens . Although the mechanism by which the GALT is able to recognize and respond to these different forms of antigen is not clear, recent studies have shown that, initially, both tolerogenic and immunogenic forms of orally administered antigen elicit transient T-cell activation and proliferation . The unique microenvironment of the GALT plays a central role in determining whether functional T-cell anergy or adaptive immunity is the ultimate response . Administration of model food proteins with adjuvants (microbial products that activate the innate immune system) induces a productive immune response to this normally tolerogenic form of antigen . Recent work from our laboratory has shown that an ongoing enteric infection can itself act as an adjuvant and prime for a response to an orally administered soluble protein antigen.

Crit Rev Immunol, 2001, 21(1-3), 1 - 27
On the initial trigger of myasthenia gravis and suppression of the disease by antibodies against the MHC peptide region involved in the presentation of a pathogenic T-cell epitope; Atassi MZ et al.; Myasthenia gravis (MG) is a disabling autoimmune disease caused by autoantibodies (auto-Abs) against the self-acetylcholine receptor (AChR) . Although a great deal of information is known about the molecular and cellular parameters of the disease, its initial trigger, however, is not known . To study the possibility of the involvement of microbial antigens that mimic AChR in triggering MG, we have searched the microbial proteins in the data bank for regions that are similar in structure to the regions of human (h) AChR alpha chain recognized by auto-Abs in MG patients . Hundreds of candidate structures on a large number of bacterial and viral proteins were identified . To test the feasibility of the idea, we synthesized four microbial regions similar to each of the major autodeterminants of hAChR (alpha12-27, alpha111-126, alpha122-138, alpha182-198) and investigated their ability to bind auto-Abs in MG and normal sera controls . It was found that MG sera potentially recognized a significant number of these microbial regions . The results indicate that in some MG cases, immune responses to microbial antigens may cross-react with self-antigen (in this case hAChR) and could constitute initial triggers of the disease . Although anti-AChR Abs directly contribute to the degradation of AChR at the neuromuscular junctions, autoreactive T cells provide help to B cells that synthesize anti-AChR auto-Abs . To cause MG, T cells must recognize the pathogenic epitopes in the context of MHC class II molecules related to MG . The ability to regulate AChR presentation (hence AChR-reactive T-cell activation) could form the basis of an effective strategy for the control of autoimmunity in MG by selectively inhibiting the function of the Ir gene loci linked to disease susceptibility . An animal model of MG (experimental autoimmune MG, EAMG) can be induced in C57BL/6 (B6, H-2b) mice by immunization with Torpedo californica (t) AChR . A mutant mouse of B6, B6.C-H-2bm12 (bm12), which has three amino acid changes (at residues 67, 70, and 71) in the I-A beta(b) subunit, is resistant to EAMG development . Recently, we showed that region 62-76 of I-A beta(b), which contains the above residues, is involved in the binding to a pathogenic T-cell epitope within peptide t alpha146-162 . We have prepared several monoclonal antibodies (mAbs) against peptide I-A beta(b)62-76, which are highly cross-reactive with I-A(b) molecules . These mAbs inhibited in vitro the proliferation of disease-related T cells of B6 specific to tAChR peptide t alpha146-162 . Passive transfer of these mAbs suppressed the occurrence of clinical EAMG, which was accompanied by lower T-cell and Ab responses to tAChR . The results indicated that blocking disease-related MHC by targeting a disease-associated region on MHC molecules could be an effective, straightforward, and feasible strategy for immunointervention in MG.

Prog Nucleic Acid Res Mol Biol, 2001, 70, 233 - 89
Nonribosomal biosynthesis of microbial chromopeptides; Keller U et al.; Nonribosomal chromopeptides and mixed chromopeptide-polyketides contain aromatic or heteroaromatic side groups which are important recognition elements for interaction with cellular targets such as DNA and proteins, resulting in the biological activities of these natural products . In the chromopeptide lactones and arylpeptide-siderophores from bacteria, the chromophore moiety--an aryl carboxylate amidated to the peptide chain--constitutes the formal amino terminus and is the starter residue of peptide assembly . Common to many arylpeptide systems is the activation by stand-alone adenylation domains and loading of the starter to discrete aryl carrier proteins (ArCPs) or ArCP domains which interact with the modules of the respective nonribosomal peptide synthetase (NRPS), assembling the next residues of the chain . Chain modification is another mechanism of nonribosomal chromopeptide synthesis where heteroaromatic rings such as thiazoles and oxazoles in peptides and polyketides are generated by heterocylizations of acyl- or peptidyl-cysteinyl or -serinyl/threonyl intermediates in each elongation step . In this review the basic mechanisms of chromophore acquisition in nonribosomal chromopeptide synthesis and mixed peptide/polyketide synthesis are illustrated by comparing the biosynthesis systems of various chromopeptides and chromopeptidic polyketide compounds.

J Ind Microbiol Biotechnol, 2001 Aug, 27(2), 80 - 6
The influence of nitrate on microbial processes in oil industry production waters; Davidova I et al.; Sulfide accumulation due to bacterial sulfate reduction is responsible for a number of serious problems in the oil industry . Among the strategies to control the activity of sulfate-reducing bacteria (SRB) is the use of nitrate, which can exhibit a variety of effects . We investigated the relevance of this approach to souring oil fields in Oklahoma and Alberta in which water flooding is used to enhance oil recovery . SRB and nitrate-reducing bacteria (NRB) were enumerated in produced waters from both oil fields . In the Oklahoma field, the rates of sulfate reduction ranged from 0.05 to 0.16 microM S day(-1) at the wellheads, and an order of magnitude higher at the oil-water separator . Sulfide production was greatest in the water storage tanks in the Alberta field . Microbial counts alone did not accurately reflect the potential for microbial activities . The majority of the sulfide production appeared to occur after the oil was pumped aboveground, rather than in the reservoir . Laboratory experiments showed that adding 5 and 10 mM nitrate to produced waters from the Oklahoma and Alberta oil fields, respectively, decreased the sulfide content to negligible levels and increased the numbers of NRB . This work suggests that sulfate reduction control measures can be concentrated on aboveground facilities, which will decrease the amount of sulfide reinjected into reservoirs during the disposal of oil field production waters.

Dynamis, 1998, 18, 427 - 46
{The impact of germ theory in the genesis of cancer . Consequences for surgical treatment in the victorian era}; Pereira Poza A; We use texts by preeminent figures in Victorian surgery at the end of the nineteenth century and information about their role in disseminating the germ theory to analyse the impact of this new etiologic element in the genesis of cancer . We trace the career of William Watson Cheyne (1852-1932), a disciple of Lister, and of many other surgeons of his generation, to outline the changes in the approach to treatment for cancer, the theoretical basis for these changes, and the role of a new conceptualization of cancer in the light of the microbial theory . This theory, among many other better-known factors, helped establish the foundation for radical surgery which became widespread in oncological treatment during the final decade of the nineteenth century.

Genes Immun, 2001 Oct, 2(6), 323 - 8
Mannan-binding lectin (MBL) gene polymorphisms in ulcerative colitis and Crohn's disease; Rector A et al.; The inflammatory bowel diseases (IBD), Crohn's disease (CD), and ulcerative colitis (UC), are complex multifactorial traits involving both environmental and genetic factors . Mannan-binding lectin (MBL) plays an important role in non-specific immunity and complement activation . Point mutations in codons 52, 54 and 57 of exon 1 of the MBL gene are associated with decreased MBL plasma concentrations and increased susceptibility to various infectious diseases . If these MBL mutations could lead to susceptibility to putative IBD-etiological microbial agents, or could temper the complement-mediated mucosal damage in IBD, MBL could function as the link between certain microbial, immunological and genetic factors in IBD . In this study, we investigated the presence of the codon 52, 54 and 57 mutations of the MBL gene in 431 unrelated IBD patients, 112 affected and 141 unaffected first-degree relatives, and 308 healthy control individuals . In the group of sporadic IBD patients (n = 340), the frequency of the investigated MBL variants was significantly lower in UC patients when compared with CD patients (P = 0.01) and with controls (P = 0.02) . These results suggest that MBL mutations which decrease the formation of functional MBL could protect against the clinical development of sporadic UC, but not of CD . This could be explained by the differential T-helper response in both diseases.

Proc Natl Acad Sci U S A, 1997 Aug 5, 94(16), 8284 - 91
Potential responses of soil organic carbon to global environmental change; Trumbore SE; Recent improvements in our understanding of the dynamics of soil carbon have shown that 20-40% of the approximately 1,500 Pg of C stored as organic matter in the upper meter of soils has turnover times of centuries or less . This fast-cycling organic matter is largely comprised of undecomposed plant material and hydrolyzable components associated with mineral surfaces . Turnover times of fast-cycling carbon vary with climate and vegetation, and range from <20 years at low latitudes to >60 years at high latitudes . The amount and turnover time of C in passive soil carbon pools (organic matter strongly stabilized on mineral surfaces with turnover times of millennia and longer) depend on factors like soil maturity and mineralogy, which, in turn, reflect long-term climate conditions . Transient sources or sinks in terrestrial carbon pools result from the time lag between photosynthetic uptake of CO2 by plants and the subsequent return of C to the atmosphere through plant, heterotrophic, and microbial respiration . Differential responses of primary production and respiration to climate change or ecosystem fertilization have the potential to cause significant interrannual to decadal imbalances in terrestrial C storage and release . Rates of carbon storage and release in recently disturbed ecosystems can be much larger than rates in more mature ecosystems . Changes in disturbance frequency and regime resulting from future climate change may be more important than equilibrium responses in determining the carbon balance of terrestrial ecosystems.

Proc Natl Acad Sci U S A, 1995 May 9, 92(10), 4158 - 63
Function of the oxidative burst in hypersensitive disease resistance; Tenhaken R et al.; Microbial elicitors or attempted infection with an avirulent pathogen strain causes the rapid production of reactive oxygen intermediates . Recent findings indicate that H2O2 from this oxidative burst plays a central role in the orchestration of the hypersensitive response: (i) as the substrate driving the cross-linking of cell wall structural proteins to slow microbial ingress prior to the deployment of transcription-dependent defenses and to trap pathogens in cells destined to undergo hypersensitive cell death, (ii) as a local threshold trigger of this programmed death in challenged cells, and (iii) as a diffusible signal for the induction in adjacent cells of genes encoding cellular protectants such as glutathione S-transferase and glutathione peroxidase . These findings provide the basis for an integrated model for the orchestration of the localized hypersensitive resistance response to attack by an avirulent pathogen.

Proc Natl Acad Sci U S A, 1992 Jul 1, 89(13), 5834 - 6
Inhibition of assimilatory nitrate reductase activity in soil by glutamine and ammonium analogs; McCarty GW et al.; Recent work in our laboratory indicated that the inhibitory effect of ammonium (NH4+) on assimilatory nitrate reductase (ANR) activity in soil is not due to NH4+ per se but to glutamine formed by microbial assimilation of NH4+ . To test this conclusion, we studied the effects of eight analogs of L-glutamine (L-glutamic acid gamma-methyl ester, L-glutamic acid gamma-hydrazide, L-glutamic acid gamma-hydroxamate, L-glutamic acid gamma-ethyl ester, L-glutamic acid dimethyl ester, L-asparagine, L-aspartic acid beta-methyl ester, and L-aspartic acid beta-hydroxamate) and two analogs of ammonium (hydroxylamine and methylamine) on ANR activity in soil slurries . The studies with the L-glutamine analogs showed that all except L-glutamic acid dimethyl ester inhibited ANR activity in soil . The sharp contrast observed between the strong inhibitory effect of L-glutamic acid gamma-methyl ester on ANR activity and the complete lack of an inhibitory effect with the corresponding dimethyl ester suggests that only the free-acid form of glutamine effectively inhibits ANR activity . The studies with hydroxylamine and methylamine showed that both of these ammonium analogs inhibited ANR activity in soil and that this inhibition was dependent upon glutamine synthetase activity . This dependence indicates that inhibition of ANR activity by hydroxylamine and methylamine was due to formation of the glutamine analogs L-glutamic acid gamma-hydroxamate and L-glutamic acid gamma-methylamide, respectively . These observations support the conclusion that the inhibitory effect of NH4+ on ANR activity in soil is due to glutamine formed by microbial assimilation of NH4+.

Res Microbiol, 2001 Sep, 152(7), 671 - 8
Estimation of the abundance of the cadmium resistance gene cadA in microbial communities in polluted estuary water; Oger C et al.; We describe herein a molecular method for estimating the abundance of the cadA gene, which encodes a Cd2+/ATPase protein transporter, in bacterial DNA extracted from samples of environmental water . Competitive polymerase chain reaction (cPCR) may be the most appropriate technique for assessing the prevalence of the cadA gene in microbial communities in highly heterogeneous and polluted environments, such as the Seine estuary (France) . We describe the development of this method: (i) the choice of two specific primers, based on the sequences encoding the cadmium binding site and the ion channel domains; (ii) the construction of a competitor sequence and assessment of its amplification efficiency; and (iii) the estimation of the copy number of the cadA gene . The cadA content in the bacterial community is expressed as the number of gene copies per ng of total DNA extracted, which is independent of the DNA extraction yield . This molecular procedure was improved to analyze cadA levels in bacterial DNA extracted from estuary water accidentally contaminated with cadmium . Results revealed a subsequent increase in the copy number of the cadA gene in the microbial community.

Prikl Biokhim Mikrobiol, 2001 Sep-Oct, 37(5), 593 - 600
{Immunosuppressors in pathogenesis of potato-pathogen blight}; Ozeretskovskaia OL et al.; The properties and effects of two plant resistance suppressors (1,3-beta-1,6-beta-glucan and a pentasaccharide of xyloglucan origin) involved in the pathosystem of potato (Solanum tuberosum) and the causal agent of blight (Phytophthora infestans (Mont) de Bary) were compared . The microbial 1,3-beta-1,6-beta-glucan suppressed the defense response over a narrow concentration range (10(-2) M), whereas the plant pentasaccharide had a broad range of effective concentrations (10(-12) to 10(-6) M) . In the pathosystem of potato-causal agent of late blight, the beta-glucan caused a local and race-specific suppressor effect on the plant host defense response . In contrast, the pentasaccharide caused both local and systemic suppression of potato resistance, and the presence of terminal fucosyl residue in the xyloglucan oligosaccharine played a decisive role in its effect . The recognition of both suppressors by potato cell membrane sites is discussed.

J Biotechnol, 2001 Dec 14, 92(1), 21 - 6
Efficient and selective microbial esterification with dry mycelium of Rhizopus oryzae; Gandolfi R et al.; The use of dry mycelium of Rhizopus oryzae as biocatalyst for ester production in organic solvent has been studied . Mycelia with notable carboxylesterase activity were produced when different Tweens (20, 40, 60 and 80) were employed as main carbon source for the growth . Dry mycelium of four strains of Rhizopus oryzae proved effective for efficiently catalysing the synthesis of different flavour esters (hexylacetate and butyrate, geranylacetate and butyrate) starting from the corresponding alcohol and free acid, including acetic acid . The esterification of the racemic mixture of 2-octanol and butyric acid proceeded with high enantioselectivity (R-ester produced with enantiomeric excess > or =97%) when Rhizopus oryzae CBS 112.07 and Rhizopus oryzae CBS 260.28 were employed.

Int J Food Microbiol, 2001 Sep 28, 69(3), 209 - 15
Considering uncertainty in comparing the burden of illness due to foodborne microbial pathogens; Powell M et al.; The uncertainty attendant to burden-of-illness estimates should be taken into account in comparing the public health impact of different foodborne pathogens . In this paper, decision analysis concepts are applied to the comparisons of pathogen-specific burden-of-illness estimates . In situations wherein the magnitude of uncertainty varies, the rank order of pathogen-specific burden-of-illness estimates is sensitive to the decisional criteria applied . To illustrate the magnitude of attendant uncertainty in pathogen-specific foodborne-illness estimates, probabilistic risk assessment methods are used to characterize the uncertainty regarding the burden of illness due to Escherichia coli O157:H7 . The magnitude of uncertainty about the burden of food-related illness due to E . coli O157:H7 is substantial, ranging from less than 50,000 to more than 120,000 cases/year . This example underscores the importance of considering the uncertainty attendant to burden-of-illness estimates in comparing the public health impacts of different pathogens . Although some would argue that the expected value of the number of illnesses provides the "best estimate" for decision-making, this merely reflects a decision-making rule of convention and not a scientific truism.

Clin Invest Med, 2001 Oct, 24(5), 250 - 7
Inflammatory bowel disease: lessons from the IL-10 gene-deficient mouse; Madsen KL; The pathogenesis of Crohn's disease likely involves multifactorial interactions between genetic factors and environmental triggers . The most recent studies suggest that luminal bacteria are a significant factor in the onset and chronicity of inflammation . In interleukin-10 (IL-10) gene-deficient mice a Crohn's-like colitis develops when the mice are raised under conventional animal care facilities but fails to develop when they are raised under germ-free conditions . These mice demonstrate significant alterations in the species and the levels of bacteria colonizing the colon, suggesting that genetic factors in the host may be critical in controlling bacterial colonization . In addition, early treatment of IL-10 gene-deficient mice with antibiotics can prevent the development of colitis in later life, suggesting that early events during the neonatal period can influence later disease progression . Recent work has focused on using probiotic bacterial mixtures to alter the microbial balance in the colon in attempts to reduce inflammation . The use of the VSL-3 probiotic mixture in the IL-10 gene-deficient mouse resulted in a complete normalization of physiological transport function and barrier integrity, in conjunction with a reduction in mucosal secretion of TNF-alpha and IFN-gamma . Further, it would appear that a soluble factor is released from a bacterium found in the VSL-3 mixture that can act directly on the epithelium to enhance barrier integrity . Results from animal models of inflammatory bowel disease suggest that genetically susceptible hosts can mount a pathogenic cellular immune response to specific nonpathogenic bacterial species, as a consequence of defective immunologic tolerance and lack of appropriate mucosal defences . Probiotic bacteria appear to be a promising new alternative for the treatment of clinical conditions that are associated with alterations in gut barrier function, including Crohn' s disease.

J Exp Med, 2001 Oct 15, 194(8), 1187 - 94
T cell-independent interleukin 15Ralpha signals are required for bystander proliferation; Lodolce JP et al.; Cytokine driven or "bystander" proliferation of T cells occurs in vivo independently of major histocompatibility complex-T cell receptor interactions . This process may be important for supporting T cell homeostasis and facilitating T cell responses to microbial antigens, and may involve the cytokine interleukin (IL)-15 . In this study, we find that IL-15Ralpha-deficient (IL-15Ralpha(-/-)) mice fail to undergo poly I:C or IL-15 driven bystander proliferation of CD8(+) T cells . Surprisingly, IL-15Ralpha(-/-) CD8(+) T cells proliferate in response to poly I:C when adoptively transferred into normal mice, and normal CD8(+) T cells fail to proliferate in IL-15Ralpha(-/-) mice . Normal mice reconstituted with IL-15Ralpha(-/-) bone marrow cells also fail to exhibit bystander responses . Thus, CD8(+) T cell independent IL-15Ralpha signals from radiation sensitive hematopoietic cells are likely required for bystander responses . Moreover, normal CD8(+) T cells proliferate in IL-15Ralpha(-/-) mice after treatment with IL-15 . Therefore, IL-15Ralpha signals may mediate a positive feedback loop involving the further physiological production of IL-15 . These findings provide new insights into how IL-15Ralpha supports memory phenotype CD8(+) T cell proliferation, and suggest novel mechanisms by which memory CD8(+) T cells are maintained in vivo.

J Biol Chem, 2001 Dec 21, 276(51), 47950 - 7 Epub 2001 Oct 15.
Lipopolysaccharide-induced expression of interferon-beta mediates the timing of inducible nitric-oxide synthase induction in RAW 264.7 macrophages; Jacobs AT et al.; The production of nitric oxide by macrophages has been implicated as a host defense mechanism against microbial pathogens and tumor cells . Recent reports have implicated interferon-alpha/beta (IFN-alpha/beta) as an autocrine/paracrine signal critical for the induction of murine iNOS . In this report we have systematically investigated the role of IFN-beta in the induction of iNOS in the murine macrophage cell line, RAW 264.7 . First, we demonstrate that IFN-beta expression is highly up-regulated, and is secreted in response to lipopolysaccharide (LPS) . Treatment of RAW macrophages with LPS results in a time-dependent phosphorylation of STAT-1 on both tyrosine residue 701 (Tyr-701) and serine residue 727 (Ser-727) that is consistent with the timing of endogenous IFN-beta expression . LPS also induces interferon regulatory factor-1 expression with similar kinetics . We further demonstrate that exogenous IFN-beta accelerates the induction of iNOS by LPS . The acceleration of iNOS induction is observed at the levels of transcription, protein expression, and NO formation . Accordingly, we propose that the cytokine environment of macrophages may determine the rate and magnitude of nitric oxide production, thereby regulating the cytotoxic response to pathogen challenge.

Perspect Biol Med, 2001 Fall, 44(4), 594 - 607
More on Merde; Lewin RA; Whereas food has always received much attention in conversation, commerce, and the literature, the subject of feces has been comparatively neglected.To fill this lacuna, a small book on comparative coprology was recently published (Lewin 1999).The present article aims to supplement this book with a review of overlooked or new items relating to biological and medical aspects of coprology, notably chemical and microbial components of human and animal feces, their uses as fertilizers, and a few other sociological impacts.

J Biol Chem, 2001 Dec 14, 276(50), 47070 - 7 Epub 2001 Oct 11.
Crustacean immunity . Antifungal peptides are generated from the C terminus of shrimp hemocyanin in response to microbial challenge; Destoumieux-Garzon D et al.; We report here the isolation from plasma of two penaeid shrimp species of novel peptides/polypeptides with exclusive antifungal activities . A set of three molecules was purified with molecular masses at 2.7 kDa (Penaeus vannamei), 7.9 kDa, and 8.3 kDa (Penaeus stylirostris) . Primary structure determination was performed by a combination of Edman degradation and mass spectrometry . The peptides display 95-100% sequence identity with a C-terminal sequence of hemocyanin, indicating that they are cleaved fragments of the shrimp respiratory protein . Specific immunodetection of the hemocyanin-derived (poly)peptides revealed that experimental microbial infections increase their relative concentration in plasma as compared with nonstimulated animals . Thus, the production of antifungal (poly)peptides by limited proteolysis of hemocyanin could be relevant to a shrimp immune reaction that would confer a new function to the multifunctional respiratory pigment of crustaceans.

Lancet, 2001 Oct 6, 358(9288), 1129 - 33
Exposure to farming in early life and development of asthma and allergy: a cross-sectional survey; Riedler J et al.; BACKGROUND: A farming environment protects against development of asthma, hay fever, and atopic sensitisation in children . We aimed to establish whether increased exposure to microbial compounds has to occur early in life to affect maturation of the immune system and thereby reduces risk for development of allergic diseases . METHODS: We did a cross-sectional survey in rural areas of Austria, Germany, and Switzerland . 2618 (75%) of 3504 parents of 6-13-year-old children completed a standardised questionnaire on asthma, hay fever, and atopic eczema . Children from farming families, and a random sample of non-farmers' children, who gave consent for blood samples to be obtained for measurements of specific serum IgE antibodies to common allergens were invited to participate (n=901) . FINDINGS: Exposure of children younger than 1 year, compared with those aged 1-5 years, to stables and consumption of farm milk was associated with lower frequencies of asthma (1% {3/218} vs 11% {15/138}), hay fever (3% {7} vs 13% {18}), and atopic sensitisation (12% {27} vs 29% {40}) . Protection against development of asthma was independent from effect on atopic sensitisation . Continual long-term exposure to stables until age 5 years was associated with the lowest frequencies of asthma (0.8% {1/122}), hay fever (0.8% {1}), and atopic sensitisation (8.2% {10}) . INTERPRETATION: Long-term and early-life exposure to stables and farm milk induces a strong protective effect against development of asthma, hay fever, and atopic sensitisation.

Crit Rev Microbiol, 2001, 27(3), 223 - 37
Can synchronous cultures of bacteria be manufactured?
Koch AL.
The bacterial cell cycle is simpler and different than that of the typical eukaryotic cell cycle . The selective pressure during evolution has been directed to achieve optimal growth of the individual free-living microbial cell instead of a variety of replication rates of the differentiated cell within an entire multicellular organism . This means that for most bacterial cells division depends more critically on their success in acquiring and using resources than is the case for most eukaryotic cells . The further implication is that bacterial cells somehow measure their own success in growth and from this 'decide' when they should attempt cell cycle events such as cell division and chromosome replication . On the assumption that bacterial division is responsive, directly or indirectly, to cell size, the cell cycle is analyzed here through Monte Carlo simulations . The results are used to consider the possibility of generating bacterial cultures growing synchronous . Because the precision of the size-at-division is surprisingly good, it appears that some organisms, at least, have a sensory mechanism that responds to their success in cell growth . It is known that the division size of some strains, however, is more precisely regulated than in others . Also, some strains are more precise in dividing the mother's cell cytoplasm to give the same sized daughters . Because some strains are much more precise than others, the possibility is raised that useful synchrony could be obtained with selected strains that are precise in these two aspects . These cultures would useful in studying other aspect of the physiology of cell growth.

Environ Toxicol Chem, 2001 Oct, 20(10), 2158 - 64
Trophic transfer and passive uptake of a polychlorinated biphenyl in experimental marine microbial communities; Wallberg P et al.; To study the uptake mechanisms of 2,2',4,4',6,6'-hexachlorobiphenyl (HxCB 153) in microplankton with different feeding strategies, two laboratory communities were used . Trophic transfer of HxCB 153 was tested in a heterotrophic microbial food web consisting of bacteria, flagellates, and ciliates . Passive uptake was tested in a community consisting of algae and bacteria . The experiments were conducted over 6 d, and samples were retrieved daily . In the heterotrophic food web, a significant increase of the HxCB 153 concentration was observed in the top predator level (ciliates, p < 0.05), where the concentration doubled during the 3 d of the experiment . A concomitant decrease was observed in the ciliate prey (flagellates), indicating that HxCB 153 was redistributed due to trophic transfer . On average, 33% of the HxCB 153 was sorbed to ciliates over the course of the experiment . In the experiment with algae and bacteria, the HxCB 153 concentrations were relatively stable over time . The largest fraction partitioned into bacteria (57%), whereas only 4% of the HxCB 153 sorbed to the algae . The uptake was 8-fold higher in ciliates than in algae, although the algal biomass was 10-fold higher . The results imply that trophic transfer may be a significant transport route of more hydrophobic organic contaminants (HOCs) in plankton communities . In transfer models, this pathway may be taken into consideration so that the transport rate of HOCs to higher trophic levels is not underestimated.

Acta Ophthalmol Scand, 2001 Oct, 79(5), 479 - 83
Contact lens induced keratitis associated with contact lens wear; Dejaco-Ruhswurm I et al.; PURPOSE: To evaluate clinical characteristics, risk factors, management and outcome of contact lens induced keratitis (CLIK) associated with contact lens wear . METHODS: The study comprised all consecutive patients presenting with contact lens related presumed microbial keratitis during a 12-month period at our department . Detailed demographic data, type of contact lens, duration of lens wear, wearing schedule and lens hygiene were derived from a self-administered questionnaire . Severity of ulcer, corneal scrapings, treatment and final outcome were evaluated . RESULTS: 27 patients with CLIK, some of which may have been sterile peripheral infiltrates, due to contact lens wear were detected . In the majority of the cases patients had used disposable soft contact lenses (89%) and most of them had a daily wearing schedule (78%) . 51.8% patients cleaned their lenses regularly . 6 (22%) applied no disinfection since their lenses were disposable on removal . In 3 of our cases with CLIK, penetrating keratoplasty had to be performed . CONCLUSION: Disposable contact lenses seem to have been a predisposing factor for contact lens induced keratitis also when used on a daily wear schedule . Insufficient contact lens care products and/or manufacturing characteristics may be responsible for CLIK, which is also observed in otherwise compliant contact lens users . In 3 of our patients with CLIK keratoplasty became necessary, indicating that contact lens induced keratitis may result in severe corneal complications.

Immunol Res, 2001, 24(2), 163 - 76
C-reactive protein, inflammation, and innate immunity; Mortensen RF; The circulating acute phase reactant C-reactive protein (CRP) has traditionally been characterized as an effector of nonclonal host resistance since it activates the classical complement cascade and mediates phagocytosis, but it is also capable of regulating inflammation . The three-dimensional structure of human CRP has revealed the molecular basis for complement activation and binding of phosphate monoesters . CRP gene expression by liver hepatocytes in response to cytokines (IL-1beta and IL-6) released in tissues requires several transcription factors which interact . Elevated levels of CRP are a prognostic marker for coronary artery disease; however, the role of CRP in atheriosclerosis remains unknown . CRP also mediates direct host protection to some microbial pathogens via its opsonic activity through certain Fcgamma-receptors . The CRP response may be one of the links between nonspecific innate immunity and specific clonal immunity.

Prog Histochem Cytochem, 2001, 36(3), 185 - 259
Maintaining corneal integrity how the "window" stays clear; Kurpakus-Wheater M et al.; The anterior surface of the eye is composed of the cornea, conjunctiva, and the zone between the two called the limbus . The cornea must maintain optical clarity to retain good vision . However, the ocular surface is vulnerable to trauma, microbial infection, and exposure to environmental toxins . This places the cornea, especially, at risk for disruptions of the epithelial barrier and subsequent immunopathological events . Cell-cell and cell-matrix attachment junctions incorporating adhesion molecules ensure that the epithelial barrier remains intact . Protein components of the basement membrane, including laminins, are vital to the adhesion of corneal epithelial cells to the underlying stroma and function to enhance the strength of the bond between epithelium and connective tissue . Epithelial cells also play an early and crucial role in the initiation of ocular surface responses should a potentially antigenic molecule enter into deeper corneal tissues . For example, epithelial cells may produce and release cytokines such as interleukin-1 (IL-1) . The delicate balance between the matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are central to mechanisms regulating dissolution of the extracellular matrix that may be a consequence of infection or wound healing . Adhesion molecules, cytokines and chemokines, and MMPs and TIMPs thus participate in the corneal response to immunologic challenge or wounding . They may also be involved in corneal pathologies associated with genetic diseases, diabetes, and vitamin A deficiency . In addition these molecules are components of cellular pathways underlying the clinical complications often observed with contact lens wear and refractive surgeries used to improve visual acuity.

Chemosphere, 2001 Oct, 45(3), 315 - 22
Chemical characteristics of organic aerosol in Bab-Ezzouar (Algiers) . Contribution of bituminous product manufacture; Yassaa N et al.; The organic compositions of atmospheric particulate matter from Bab-Ezzouar (Algiers) have been investigated to assess the air pollution levels suspected to be caused by asphalt product and yeast manufactures . After a medium-volume air sampling, soxhlet extraction, alumina elution and HPLC separation, the extracts were analysed by high-resolution gas chromatography (HRGC) and gas chromatography coupled to mass spectrometry (GC-MS) . The composition of n-alkane and polycyclic aromatic hydrocarbons (PAH) fractions reflected the petrogenic origin from the emission of asphalt materials production in addition to vascular plant wax emissions . In contrast, microbial activities seemed to play the main role for the presence of n-alkanoic acids at Bab-Ezzouar . The sole nitrated polycyclic aromatic hydrocarbons (NPAH) observed, i.e., 2-nitrofluoranthene (2NFA), was very likely to arise from gas-phase photochemical reaction of parent PAH in the atmosphere . The total aerial levels ranged from 75 to 206 ng m(-3) for n-alkanes, from 153 to 345 ng m(-3) for n-alkanoic acids and from 44 to 100 ng m(-3) for PAH and NPAH . Although the samples were collected during the hot season, the levels of these pollutants seemed to be important and of environmental concern, especially for PAH species.

Am J Vet Res, 2001 Oct, 62(10), 1519 - 24
Involvement of microbial respiratory pathogens in acute interstitial pneumonia in feedlot cattle; Loneragan GH et al.; OBJECTIVE: To evaluate viral and bacterial respiratory pathogens and Mycoplasma spp isolated from lung tissues of cattle with acute interstitial pneumonia (AIP) and cattle that had died as a result of other causes . SAMPLE POPULATION: 186 samples of lung tissues collected from cattle housed in 14 feedlots in the western United States . PROCEDURE: Lung tissues were collected during routine postmortem examination and submitted for histologic, microbiologic, and toxicologic examinations . Histologic diagnoses were categorized for AIP, bronchopneumonia (BP), control samples (no evidence of disease), and other disorders . RESULTS: Cattle affected with AIP had been in feedlots for a mean of 1272 days before death, which was longer than cattle with BP and control cattle . Detection of a viral respiratory pathogen (eg, bovine respiratory syncytial virus {BRSV}, bovine viral diarrhea virus, bovine herpesvirus 1, or parainfluenza virus 3) was not associated with histologic category of lung tissues . Bovine respiratory syncytial virus was detected in 8.3% of AIP samples and 24.0% of control samples . Histologic category was associated with isolation of an aerobic bacterial agent and Mycoplasma spp . Cattle with BP were at greatest risk for isolation of an aerobic bacterial agent and Mycoplasma spp . CONCLUSIONS AND CLINICAL RELEVANCE: Analysis of these results suggests that AIP in feedlot cattle is not a consequence of infection with BRSV . The increased, risk of isolation of an aerobic bacterial agent from cattle with AIP, compared with control cattle, may indicate a causal role or an opportunistic infection that follows development of AIP.

Eur J Immunol, 2001 Oct, 31(10), 3026 - 37
Toll-like receptor expression reveals CpG DNA as a unique microbial stimulus for plasmacytoid dendritic cells which synergizes with CD40 ligand to induce high amounts of IL-12; Krug A et al.; Human plasmacytoid dendritic cells (DC) (PDC, CD123+) and myeloid DC (MDC, CD11c+) may be able to discriminate between distinct classes of microbial molecules based on a different pattern of Toll-like receptor (TLR) expression . TLR1-TLR9 were examined in purified PDC and MDC . TLR9, which is critically involved in the recognition of CpG motifs in mice, was present in PDC but not in MDC . TLR4, which is required for the response to LPS, was selectively expressed on MDC . Consistent with TLR expression, PDC were susceptible to stimulation by CpG oligodeoxynucleotide (ODN) but not by LPS, while MDC responded to LPS but not to CpG ODN . In PDC, CpG ODN supported survival, activation (CD80, CD86, CD40, MHC class II), chemokine production (IL-8, IP-10) and maturation (CD83) . CD40 ligand (CD40L) and CpG ODN synergized to activate PDC and to stimulate the production of IFN-alpha and IL-12 including bioactive IL-12 p70 . Previous incubation of PDC with IL-3 decreased the amount of CpG-induced IFN-alpha and shifted the cytokine response in favor of IL-12 . CpG ODN-activated PDC showed an increased ability to stimulate proliferation of naive allogeneic CD4 T cells, butTh1 polarization of developing T cells required simultaneous activation of PDC by CD40 ligation and CpG ODN . CpG ODN-stimulated PDC expressed CCR7, which mediates homing to lymph nodes . In conclusion, our studies reveal that IL-12 p70 production by PDC is under strict control of two signals, an adequate exogenous microbial stimulus such as CpG ODN, and CD40L provided endogenously by activated T cells . Thus, CpG ODN acts as an enhancer of T cell help, while T cell-controlled restriction to foreign antigens is maintained.

J Immunol, 2001 Oct 15, 167(8), 4147 - 53
Induction of IL-10 and inhibition of experimental arthritis are specific features of microbial heat shock proteins that are absent for other evolutionarily conserved immunodominant proteins; Prakken BJ et al.; Bacterial heat shock proteins (hsp) are evolutionary conserved immunodominant proteins that manifest amino acid homologies with hsp present in mammalian cells . Preimmunization with mycobacterial hsp65 has been found to protect against various forms of experimental arthritis . As these protective effects have previously been attributed to induction of self homologue cross-reactive T cell responses, the question was raised as to whether this protective effect could be extended to other highly conserved and immunodominant microbial Ags with mammalian homologues . Therefore, we immunized Lewis rats with conserved bacterial Ags (superoxide dismutase, aldolase, GAPDH, and hsp70) . Although all Ags appeared highly immunogenic, we only found a protective effect in experimental arthritis after immunization with bacterial hsp70 . The protective effect of hsp70 was accompanied with a switch in the subclasses of hsp70-specific Abs, suggesting the induction of Th2-like response . The most striking difference between immunization with hsp70 and all other immunodominant Ags was the expression of IL-10 found after immunization with hsp70 . Even more, while immunization with hsp70 led to Ag-induced production of IL-10 and IL-4, immunization with aldolase led to increased production of IFN-gamma and TNF-alpha . Thus, the protective effect of conserved immunodominant proteins in experimental arthritis seems to be a specific feature of hsp . Therefore, hsp may offer unique possibilities for immunological intervention in inflammatory diseases.

J Environ Sci (China), 2001 Jul, 13(3), 311 - 7
Combined effects of two sulfonylurea herbicides on soil microbial biomass and N-mineralization; el-Ghamry AM et al.; The interaction effect of two sulfonylurea herbicides, bensulfuron-methyl (B) and metsulfuron-methyl(M), were tested on microbial biomass C, N, N-mineralization and C/N ratio in a loamy sand soil . The herbicides were applied at various levels of: control (B0M0), 0.01 and 0.01 (B1M1), 0.01 and 0.1 (B1M2), and 0.01 and 1.0 (B1M3) microgram/g soil . Determinations of soil microbial biomass-C, N and N-mineralization contents were carried out at 1, 3, 5, 7, 10, 15, 25 and 45 days after herbicides application . The results showed that the soil microbial biomass-C (Cmic) and microbial biomass-N (Nmic) decreased consistently with the increasing rates of herbicides . The results further indicated that B1M1 and B1M2 caused a significant reduction in Cmic and Nmic within first 10 and 7 days of incubation, respectively, as compared with the control . These reductions in Cmic and Nmic were also significant (P = 0.05) with B1M3 application especially within first 15 days of incubation . A significant reduction in N-mineralization (N-min) was observed with high doses (B1M2, B1M3) of herbicides within first 5 days of incubation, while low rate (B1M1) failed to produce any significant effect . An increase in the soil microbial biomass C:N ratio was also noted.

Eur J Clin Invest, 2001 Sep, 31(9), 821 - 31
Fcgamma receptors in autoimmune diseases; Fossati G et al.; Fcgamma-receptors (Fcgamma-R) recognise the Fc portion of IgG and thus form a link between humoral and cellular immunity . These receptors are expressed by a variety of immune cells, and they function in the binding of immune complexes or IgG-opsonised particles, such as microbial pathogens . The are three major types of Fcgamma-R, namely Fcgamma-RI (CD64), Fcgamma-RII (CD32) and Fcgamma-RIII (CD16), and these differ in their ability to bind IgG and complexes . There are many isoforms of these receptors and a number of recently identified polymorphisms in their structure . This review describes the structure and function of these Fcgamma-Rs, and highlights how gene deficiencies and polymorphisms may contribute to the pathology of human diseases.

J Contam Hydrol, 2001 Oct, 51(3-4), 179 - 95
In situ assessment of microbial sulfate reduction in a petroleum-contaminated aquifer using push-pull tests and stable sulfur isotope analyses; Schroth MH et al.; Anaerobic microbial activities such as sulfate reduction are important for the degradation of petroleum hydrocarbons (PHC) in contaminated aquifers . The objective of this study was to evaluate the feasibility of single-well push-pull tests in combination with stable sulfur isotope analyses for the in situ quantification of microbial sulfate reduction . A series of push-pull tests was performed in an existing monitoring well of a PHC-contaminated aquifer in Studen (Switzerland) . Sulfate transport behavior was evaluated in a first test . In three subsequent tests, we injected anoxic test solutions (up to 1000 l), which contained 0.5 mM bromide (Br-) as conservative tracer and 1 mM sulfate (SO4(2-)) as reactant . After an initial incubation period of 42.5 to 67.9 h, up to 1100 l of test solution/groundwater mixture was extracted in each test from the same location . During the extraction phases, we measured concentrations of relevant species including Br-, SO4(2-) and sulfide (S(-II)), as well as stable sulfur isotope ratios (delta 34S) of extracted, unconsumed SO4(2-) and extracted S(-II) . Results indicated sulfate reduction activity in the vicinity of the test well . Computed first-order rate coefficients for sulfate reduction ranged from 0.043 +/- 0.013 to 0.130 +/- 0.015 day-1 . Isotope enrichment factors (epsilon) computed from sulfur isotope fractionation of extracted, unconsumed SO4(2-) ranged from 20.2 +/- 5.5@1000 to 22.8 +/- 3.4@1000 . Together with observed fractionation in extracted S(-II), isotope enrichment factors provided strong evidence for microbially mediated sulfate reduction . Thus, push-pull tests combined with stable sulfur isotope analyses proved useful for the in situ quantification of microbial sulfate reduction in a PHC-contaminated aquifer.

Biotechnol Prog, 2001 Sep-Oct, 17(5), 852 - 9
Impact of nitrate-mediated microbial control of souring in oil reservoirs on the extent of corrosion; Nemati M et al.; The effect of microbial control of souring on the extent of corrosion was studied in a model system consisting of pure cultures of the nitrate-reducing, sulfide-oxidizing bacterium (NR-SOB) Thiomicrospira sp . strain CVO and the sulfate-reducing bacterium (SRB) Desulfovibrio sp . strain Lac6, as well as in an SRB consortium enriched from produced water from a Canadian oil reservoir . The average corrosion rate induced by the SRB consortium (1.4 g x m(-2) x day(-1)) was faster than that observed in the presence of strain Lac6 (0.2 g x m(-2) x day(-1)) . Examination of the metallic coupons at the end of the tests indicated a uniform corrosion in both cases . Addition of CVO and 10 mM nitrate to a fully grown culture of Lac6 or the SRB consortium led to complete removal of sulfide from the system and a significant increase in the population of CVO, as determined by reverse sample genome probing . In the case of the SRB consortium addition of just nitrate (10 mM) had a similar effect . When grown in the absence of nitrate, the consortium was dominated by Desulfovibrio sp . strains Lac15 and Lac29, while growth in the presence of nitrate led to dominance of Desulfovibrio sp . strain Lac3 . The addition of CVO and nitrate to the Lac6 culture or nitrate to the SRB consortium accelerated the average corrosion rate to 1.5 and 2.9 g x m(-2) x day(-1), respectively . Localized corrosion and the occurrence of pitting were apparent in both cases . Although the sulfide concentration (0.5-7 mM) had little effect on corrosion rates, a clear increase of the corrosion rate with increasing nitrate concentration was observed in experiments conducted with consortia enriched from produced water.

Gastroenterol Clin North Am, 2001 Sep, 30(3), 837 - 54
Biotherapeutic agents in the treatment of infectious diarrhea; Elmer GW et al.; Biotherapeutic agents offer unique advantages over traditional treatments for infectious diarrhea, and several have been shown to be effective (Table 4) . These therapeutic microbial agents are most effective in types of infectious diseases that are associated with a disruption of the normal intestinal microecology (e.g., AAD, C . difficile disease) . The impact of biotherapeutic agents on rotaviral diarrhea is of special clinical importance because this is the most common cause of pediatric diarrhea, and there is no defined treatment . Strong efforts need to be made to limit antibiotic exposure in children . Biotherapeutic agents offer a safe and effective nonantibiotic method of treating this important pathogen, especially after the withdrawal of a rotaviral vaccine from the market by the FDA . However, for many biotherapeutic agents, well-done, placebo-controlled trials still are lacking, and not all types of infectious diarrhea respond to these agents . Continued research in this innovative therapeutic area is warranted.

J Allergy Clin Immunol, 2001 Oct, 108(4 Suppl), S104 - 6
Activation of toll-like receptors by microbial lipoproteins: role in host defense; Modlin RL; Conserved throughout evolution, mammalian toll-like receptors (TLRs) participate in innate immune response to microbial pathogens . The TLRs mediate activation by microbial ligands, resulting in cytokine activation as well as other host defense mechanisms . Activation of TLRs also can result in tissue injury including manifestations of septic shock and host cell apoptosis . In this manner, the activation of mammalian TLRs in the context of infectious disease can contribute to host defense and immunopathology.

Nat Cell Biol, 2001 Oct, 3(10), 891 - 6
Endoplasmic reticulum chaperone gp96 is required for innate immunity but not cell viability; Randow F et al.; Chaperone proteins are thought to promote the correct folding and assembly of newly synthesized proteins and to facilitate restoration of the folded state under environmental conditions that favour protein denaturation . They are among the most ubiquitous and highly conserved of all proteins . The eukaryotic endoplasmic reticulum (ER) chaperone gp96 in particular has long been thought to be indispensable for cell survival . Here we report that a screen for genes required for the immune response to bacterial endotoxins has identified a B-cell line deficient in gp96 . Absence of gp96 is compatible with cellular survival even under stress conditions and causes a defect in the formation of only a small subset of cell surface receptors . Toll-like receptors are retained intracellularly in the absence of gp96, explaining the unresponsiveness of the mutant to microbial stimuli.

Am J Pathol, 2001 Oct, 159(4), 1199 - 209
Molecular signatures of sepsis: multiorgan gene expression profiles of systemic inflammation; Chinnaiyan AM et al.; During sepsis the host's system-wide response to microbial invasion seems dysregulated . Here we explore the diverse multiorgan transcriptional programs activated during systemic inflammation in a cecal ligation/puncture model of sepsis in rats . Using DNA microarrays representing 7398 genes, we examined the temporal sequence of sepsis-induced gene expression patterns in major organ systems including lung, liver, kidney, thymus, spleen, and brain . Although genes known to be associated with systemic inflammation were identified by our global transcript analysis, many genes and expressed sequence tags not previously linked to the septic response were also elucidated . Taken together, our results suggest activation of a highly complex transcriptional response in individual organs of the septic animal . Several overlying themes emerged from our genome-scale analysis that includes 1) the sepsis response elicited gene expression profiles that were either organ-specific, common to more than one organ, or distinctly opposite in some organs; 2) the brain is protected from sepsis-induced gene activation relative to other organs; 3) the thymus and spleen have an interesting cohort of genes with opposing gene expression patterns; 4) genes with proinflammatory effects were often balanced by genes with anti-inflammatory effects (eg, interleukin-1beta/decoy receptor, xanthine oxidase/superoxide dismutase, Ca2+-dependent PLA2/Ca2+-independent PLA2); and 5) differential gene expression was observed in proteins responsible for preventing tissue injury and promoting homeostasis including anti-proteases (TIMP-1, Cpi-26), oxidant neutralizing enzymes (metallothionein), cytokine decoy receptors (interleukin-1RII), and tissue/vascular permeability factors (aquaporin 5, vascular endothelial growth factor) . This global perspective of the sepsis response should provide a molecular framework for future research into the pathophysiology of systemic inflammation . Understanding, on a genome scale, how an organism responds to infection, may facilitate the development of enhanced detection and treatment modalities for sepsis.

Biochemistry, 2001 Aug 14, 40(32), 9460 - 8
Protein interactions leading to conformational changes monitored by limited proteolysis: apo form and fragments of horse cytochrome c; Spolaore B et al.; Proteolysis experiments have been used to monitor the conformational transitions from an unfolded to a folded state occurring when the apo form of horse cytochrome c (cyt c) binds the heme moiety or when two fragments of cyt c form a native-like 1:1 complex . Proteinase K was used as a proteolytic probe, in view of the fact that the broad substrate specificity of this protease allows digestion at many sites along a polypeptide chain . The rather unfolded apo form of cyt c binds heme with a concomitant conformational transition to a folded species characterized by an enhanced content of helical secondary structure . While the holoprotein is fully resistant to proteolytic digestion and the apoprotein is digested to small peptides, the noncovalent complex of the apoprotein and heme exhibits an intermediate resistance to proteolysis, in agreement with the fact that the more folded structure of the complex makes the protein substrate more resistant to proteolysis . The noncovalent native-like complex of the two fragments 1-56 and 57-104 of cyt c, covering the entire polypeptide chain of 104 residues of the protein, is rather resistant to proteolysis, while the individual fragments are easily digested . Fragment 57-104 is fast degraded to several peptides, while fragment 1-56 is slowly degraded stepwise from its C-terminal end, leading initially mostly to fragments 1-48 and 1-40 and, at later stages of proteolysis, fragments 1-38, 1-35, 1-33, and 1-31 . Thus, proteolysis data indicate that the heme containing fragment 1-56 has a rather compact core and a C-terminal flexible tail . Upon prolonged incubation of the complex of fragments 1-56 and 57-104 (nicked cyt c) with proteinase K, a chain segment is removed from the nicked protein, leading to a gapped protein complex of fragments of 1-48 and 57-104 and, on further digestion, fragments 1-40 and 57-104 . Of interest, the chain segment being removed by proteolysis of the complex matches the omega-loop which is evolutionarily removed in cyt c of microbial origin . Overall, rates and/or resistance to proteolysis correlates well with the extent of folding of the protein substrates, as deduced from circular dichroism measurements . Thus, our results underscore the utility of proteolytic probes for analyzing conformational and dynamic features of proteins . Finally, a specific interest of the cyt c fragment system herewith investigated resides in the fact that the fragments are exactly the exon products of the cyt c gene.

Eur J Endocrinol, 2001 Oct, 145(4), 477 - 83
Phosphoinositide 3-kinase inhibits megalin-mediated transcytosis of thyroglobulin across thyroid epithelial cells at a post-sorting level; Marino M et al.; BACKGROUND: Phosphoinositide 3-kinase (PI3-K) is implicated in various cellular processes involving signaling, including intracellular trafficking . PI3-K has been shown to play a part in both receptor- and non-receptor-mediated transcytosis across cultured kidney cells and undifferentiated thyroid cells . OBJECTIVE: To investigate the role of PI3-K in transcytosis of thyroglobulin (Tg) across differentiated cultured Fisher rat thyroid cells (FRTL-5 cells) - a process known to be mediated by megalin, a member of the low-density lipoprotein receptor family . DESIGN: We studied the effect of the microbial product wortmannin, a specific inhibitor of PI3-K, on transcytosis of Tg across FRTL-5 cells . METHODS: Transcytosis experiments were performed using FRTL-5 cells cultured as tight layers on filters in the upper chamber of dual chambered devices, with megalin expression exclusively on the upper cell surface . Tg was added to the upper chamber and cells were incubated at 37 degrees C . Transcytosed Tg was measured in fluids collected from the lower chamber . To study the role of PI3-K, cells were pre-incubated with wortmannin . RESULTS: Pre-incubation of FRTL-5 cells with wortmannin did not affect Tg binding and uptake, but resulted in a considerable increase in Tg transcytosis (by 40-75%, depending on the concentration of wortmannin), suggesting that PI3-K exerts an inhibitory effect on Tg transcytosis . In experiments in which a monoclonal antibody against megalin was used to reduce Tg transcytosis, pre-incubation with wortmannin did not increase Tg transcytosis from its reduced levels, indicating that PI3-K is involved in the megalin-mediated pathway . Wortmannin did not affect the extent of release of tri-iodothyronine from exogenously added Tg by FRTL-5 cells, which was used as a measure of Tg degradation in the lysosomal pathway, indicating that the effect of PI3-K on transcytosis occurs after diversion of Tg from the lysosomal pathway . CONCLUSIONS: PI3-K exerts an inhibitory role on megalin-mediated Tg transcytosis across cultured thyroid cells . PI3-K action takes place at a post-sorting level, after Tg bypassing of the lysosomal pathway.

Microbes Infect, 2001 Aug, 3(10), 813 - 21
Microarrays for studying the host transcriptional response to microbial infection and for the identification of host drug targets; Yowe D et al.; It is essential to understand the molecular basis of a host's response to microbial infection so that disease and tissue damage can be prevented . Modulation of host RNA expression is a critical set of molecular changes that occur upon infection . Global analysis of gene expression should provide an understanding of host RNA transcriptional changes that occur upon host-pathogen interaction . This series of articles focuses on the use of microarrays for analyzing the transcriptional response of a host to microbial infection and for drug target identification.

J Med Entomol, 2001 Sep, 38(5), 711 - 9
Bacterial and fungal biomass responses to feeding by larval Aedes triseriatus (Diptera: Culicidae); Kaufman MG et al.; We investigated the effect of different densities (0, 20, or 40) of developing larval Aedes triseriatus (Say) on bacterial abundance, bacterial productivity, and leaf fungal biomass in a microcosm experiment . Larvae in the low-density treatment developed normally, but larvae at the high density were significantly slower to develop . Both bacterial abundance (direct microscopic counts) and bacterial productivity (3H-leucine incorporation rates) on leaf material were significantly lower in the presence of larvae . Bacterial abundance in the water column did not change significantly with treatment, but bacterial productivity varied with time and declined significantly at both larval densities . Bacteria on the walls and bottom of the containers also were less abundant and significantly less productive in the presence of larvae . Aside from presence/absence effects, there was no clear evidence that larval impacts were density-dependent . Leaf-associated fungal biomass, as measured by ergosterol levels, varied with time but was not significantly affected by any treatment, suggesting most fungal tissue was incorporated in the leaf matrix and unavailable to larvae . Based upon estimated biomass accrual and respiration of larvae, it appears that bacterial biomass and production were insufficient to account for carbon demands of growing larvae . Because fungal biomass and leaf mass likely contributed little to gross larval demands, other carbon sources (e.g., protozoa and extracellular microbial components) were probably used by larvae . Although apparently insufficient for all larval carbon demands, bacterial and leaf fungal biomass may be adequate for other larval nutritional needs (i.e., nitrogen and essential lipids).

Pharmacol Ther, 2001 May-Jun, 90(2-3), 157 - 77
Dietary agents in cancer prevention: flavonoids and isoflavonoids; Birt DF et al.; Flavones and isoflavones may play a prominent role in cancer prevention since these compounds are found in numerous plants that are associated with reduced cancer rates . This article reviews recent epidemiological and animal data on isoflavones and flavones and their role in cancer prevention . It covers aspects of the bioavailability of these dietary constituents and explores their mechanism of action . Human epidemiology data comes primarily from studies in which foods rich in isoflavones or flavones are associated with cancer rates . This approach has been particularly useful with isoflavones because of their abundance in specific foods, including soy foods . The bioavailability of flavones and isoflavones has been shown to be influenced by their chemical form in foods (generally glycoside conjugates), their hydrophobicity, susceptibility to degradation, the microbial flora of the consumer, and the food matrix . Some information is available on how these factors influence isoflavone bioavailability, but the information on flavones is more limited . Many mechanisms of action have been identified for isoflavone/flavone prevention of cancer, including estrogenic/antiestrogenic activity, antiproliferation, induction of cell-cycle arrest and apoptosis, prevention of oxidation, induction of detoxification enzymes, regulation of the host immune system, and changes in cellular signaling . It is expected that some combination of these mechanisms will be found to be responsible for cancer prevention by these compounds . Compelling data suggest that flavones and isoflavones contribute to cancer prevention; however, further investigations will be required to clarify the nature of the impact and interactions between these bioactive constituents and other dietary components.

Environ Microbiol, 2001 Aug, 3(8), 532 - 42
Molecular analysis of microbial community structure in an arsenite-oxidizing acidic thermal spring; Jackson CR et al.; Electron microscopy (EM), denaturing gradient gel electrophoresis (DGGE) and 16S rDNA sequencing were used to examine the structure and diversity of microbial mats present in an acid-sulphate-chloride (pH 3.1) thermal (58-62 degrees C) spring in Norris Basin, Yellowstone National Park, WY, USA, exhibiting rapid rates of arsenite oxidation . Initial visual assessments, scanning EM and geochemical measurements revealed the presence of three distinct mat types . Analysis of 16S rDNA fragments with DGGE confirmed the presence of different bacterial and archaeal communities within these zones . Changes in the microbial community appeared to coincide with arsenite oxidation activity . Phylogenetic analysis of 1400 bp 16S rDNA sequences revealed that clone libraries prepared from both arsenic redox active and inactive bacterial communities were dominated by sequences phylogenetically related to Hydrogenobacter acidophilus and Desulphurella sp . The appearance of archaeal 16S rDNA sequences coincided with the start of arsenite oxidation, and sequences were obtained showing affiliation with both Crenarchaeota and Euryarchaeota . The majority of archaeal sequences were most similar to sequences obtained from marine hydrothermal vents and other acidic hot springs, although the level of similarity was typically just 90% . Arsenite oxidation in this system may result from the activities of these unknown archaeal taxa and/or the previously unreported arsenic redox activity of H . acidophilus- or Desulphurella-like organisms . If the latter, arsenite oxidation must be inhibited in the initial high-sulphide zone of the spring, where no change in the distribution of arsenite versus arsenate was observed.

Altern Med Rev, 2001 Aug, 6(4), 390 - 405
Metabolic and immunologic consequences of ABH secretor and Lewis subtype status; D'Adamo PJ et al.; Determining ABH secretor phenotype and/or Lewis (Le) blood group status can be useful to the metabolically-oriented clinician . For example, differences in ABH secretor status drastically alter the carbohydrates present in body fluids and secretions; this can have profound influence on microbial attachment and persistence . Lewis typing is one genetic marker which might help identify subpopulations of individuals genetically prone to insulin resistance, autoimmunity, and heart disease . Understanding the clinical significance of ABH secretor status and the Lewis blood groups can provide insight into seemingly unrelated aspects of physiology, including variations in intestinal alkaline phosphatase activity, propensities toward blood clotting, reliability of some tumor markers, the composition of breast milk, and several generalized aspects of the immune function . Since the relevance of ABH blood group antigens as tumor markers and parasitic/bacterial/viral receptors and their association with immunologically important proteins is now well established, the prime biologic role for ABH blood group antigens may well be independent and unrelated to the erythrocyte.

J Org Chem, 2001 Oct 5, 66(20), 6768 - 74
A chemoenzymatic total synthesis of ent-bengamide E; Banwell MG et al.; The cis-1,2-dihydrocatechol 3, which can be obtained in enantiomerically pure form by microbial dihydroxylation of bromobenzene, has been converted into the enantiomer, ent-1, of the cyclolysine-based marine natural product bengamide E (1).

Inorg Chem, 2001 Oct 8, 40(21), 5420 - 7
Use of SDS micelles to stabilize a ternary intermediate in the reaction of ferrioxamine B and 1,10-phenanthroline; Olmstead EG Jr et al.; Spectrophotometric measurements of the reaction of ferrioxamine B (FeHDFB(+)) with 1,10-phenanthroline (phen) reveal the presence of a ternary intermediate complex in both aqueous solution and an aqueous solution of 0.16 M sodium dodecyl sulfate (SDS) . The stoichiometry of the intermediate is Fe(H(2)DFB)(phen)(2+) on the basis of a Schwarzenbach analysis of spectrophotometric data obtained at variable pH and phen concentrations . The ternary complex formation constant for the reaction FeHDFB(+) + H(+) + phen right arrow over left arrow Fe(H(2)DFB)(phen)(2+) is log K = 6.96 in aqueous solution and log K = 8.64 in aqueous 0.16 M SDS . The enhanced stability of Fe(H(2)DFB)(phen)(2+) in micellar solution was analyzed in terms of the pseudophase ion-exchange (PPIE) model of micellar reactions . The association constants for the binding of each reactant to the micellar pseudophase were measured by ultrafiltration . According to PPIE model calculations, the enhanced stability of Fe(H(2)DFB)(phen)(2+) in micellar SDS arises from a proximity effect created by the high local concentrations of reactants in the micellar pseudophase . The calculations also indicate that an inhibitory medium or compartmentalization effect is operative since the observed micellar enhancement is much smaller than predicted by the PPIE model . The micellar stabilization of the Fe(H(2)DFB)(phen)(2+) intermediate and the overall conversion of FeHDFB(+) to Fe(phen)(3)(2+) are discussed as a possible model system for siderophore iron release in microbial organisms.

J Periodontol, 2001 Sep, 72(9), 1146 - 50
Fluids and microbial penetration in the internal part of cement-retained versus screw-retained implant-abutment connections; Piattelli A et al.; BACKGROUND: It has been recently observed that in implants with screw-retained abutments, in in vitro as well as in vivo conditions, bacteria can penetrate inside the internal cavity of the implant as a consequence of leakage at the implant-abutment interface . An alternative to screw-retained abutments is represented by implants that can receive cemented abutments . In this case, the abutment goes through a transmucosal friction implant extension (collar) and is cemented inside the internal hexagonal portion of the implant . The aim of the present research was to compare fluids and bacterial penetration in 2 different implant systems, one with cement-retained abutments (CRA) and the other with screw-retained abutments (SRA) . METHODS: Twelve CRA dental implants and 12 SRA implants were used in this study . The research was done in 3 steps: scanning electron microscopic (SEM) analysis, fluid penetration analysis, and bacterial penetration analysis . RESULTS: 1) Under SEM it was possible to observe in the SRA implants a mean 2 to 7 micron gap between implant and abutment, while in the CRA implants, the gap was 7 micron . In the latter group, however, the gap was always completely filled by the fixation cement . All the spaces between abutment and implant were filled by the cement . 2) With SRA implants, it was possible to observe the presence of toluidine blue at the level of the fixture-abutment interface and the internal threads; the absorbent paper was stained in all cases . With CRA implants, the absorbent paper inside the hollow portion of the implants was never stained by toluidine blue . No penetration of toluidine blue was observed at the implant-abutment interface and inside the hollow portion of the implants . 3) In all the SRA implant assemblies, bacterial penetration was observed at the implant-abutment interface . No bacteria were detected in the hollow portion of the CRA implants . CONCLUSION: On the basis of the results obtained in the present study using 2 different implant systems, we conclude that CRA implants offer better results relating to fluid and bacterial permeability compared to SRA implants.

J Environ Qual, 2001 Sep-Oct, 30(5), 1604 - 11
Screening for organotin compounds in European landfill leachates; Mersiowsky I et al.; As industrial chemicals, organotin compounds are predominantly applied as polyvinyl chloride (PVC) stabilizers and biocides . They are widely encountered in environmental samples and may be introduced into landfills by disposal of municipal solid waste or sewage sludge . In the present study, leachate samples were obtained from several sanitary landfill sites in Sweden, Italy, and Germany . These samples were analyzed by means of a highly sensitive and species-selective method for methyltin, butyltin, and octyltin species . In total, twelve samples from eight different landfill sites at various ages were investigated . The findings of all target compounds range between less than the limit of detection at 0.1 microg/L and, at maximum, 4 microg/L . Only octyltin compounds can be attributed to PVC products with any certainty, whereas for methyltin and butyltin compounds alternative and less distinct sources exist . Organotin compounds are subject to microbial transformation, such as dealkylation and methylation processes . Consequently, caution should be exercised when attributing findings to potential sources and deriving any predicted environmental concentrations.

J Environ Qual, 2001 Sep-Oct, 30(5), 1508 - 15
Spatiotemporal variability of wet atmospheric nitrogen deposition to the Neuse River Estuary, North Carolina; Whitall DR et al.; Excessive nitrogen (N) loading to N-sensitive waters such as the Neuse River estuary (North Carolina) has been shown to promote changes in microbial and algal community composition and function (harmful algal blooms), hypoxia and anoxia, and fish kills . Previous studies have estimated that wet atmospheric deposition of nitrogen (WAD-N), as deposition of dissolved inorganic nitrogen (DIN: NO3-, NH3/NH4+) and dissolved organic nitrogen, may contribute at least 15% of the total externally supplied or "new" N flux to the coastal waters of North Carolina . In a 3-yr study from June 1996 to June 1999, we calculated the weekly wet deposition of inorganic and organic N at eleven sites on a northwest-southeast transect in the watershed . The annual mean total (wet DIN + wet organics) WAD-N flux for the Neuse River watershed was calculated to be 956 mg N/m2/yr (15026 Mg N/yr) . Seasonally, the spring (March-May) and summer (June-August) months contain the highest total weekly N deposition; this pattern appears to be driven by N concentration in precipitation . There is also spatial variability in WAD-N deposition; in general, the upper portion of the watershed receives the lowest annual deposition and the middle portion of the watershed receives the highest deposition . Based on a range of watershed N retention and in-stream riverine processing values, we estimate that this flux contributes approximately 24% of the total "new" N flux to the estuary.

J Microbiol Methods, 2001 Nov, 47(2), 159 - 67
A novel method for the measurement of dissolved adenosine and guanosine triphosphate in aquatic habitats: applications to marine microbial ecology; Bjorkman KM et al.; A novel method for the measurement of dissolved adenosine-5'-triphosphate and guanosine-5'-triphosphate (D-ATP and D-GTP, respectively) in marine and freshwater habitats was developed and applied to samples collected from the oligotrophic North Pacific Ocean . Both D-ATP and D-GTP are co-precipitated by authigenically formed Mg(OH)(2) and can be concentrated by factors greater than 200-fold, for subsequent measurement by the firefly luciferin-luciferase bioluminescence reaction . The detection limit for this method was 2-3 pmol ml(-1) of concentrated sample (equivalent to an in situ concentration of 10 pM) with a 5% precision at concentrations of 10 pmol ml(-1) or above.A significant positive correlation (P<0.001) was observed between particulate ATP (P-ATP) and D-ATP in water samples collected from Station ALOHA (22.75 degrees N, 158 degrees W; depth profiles 0-1000 m) . The highest concentrations of dissolved nucleotides were found in the euphotic zone (0-175 m) below which the concentrations were low and relatively invariant . The dissolved nucleotide pools generally exceeded their corresponding particulate pools.Using radioisotopic tracer techniques and the new concentration method, turnover times for both particulate and dissolved nucleotides can be determined . The ability to measure concentrations and follow nucleotide tracers accurately in a very dilute environment provides a unique opportunity to address questions on microbial community metabolism, nutrient dynamics and energy flux.

J Appl Microbiol, 2001 Oct, 91(4), 668 - 76
Microcosm enrichment of 1,3-dichloropropene-degrading soil microbial communities in a compost-amended soil; Ibekwe AM et al.; AIMS: A microcosm-enrichment approach was used to investigate bacterial populations that may represent 1,3-dichloropropene (1,3-D)-degrading micro-organisms in compost-amended soil . METHODS AND RESULTS: After 8 weeks of incubation, with repeated application of 1,3-D, volatilization fluxes were much lower for compost-amended soil (CM) than with the unamended soils, indicating accelerated degradation due to addition of compost, or development of new microbial populations with enhanced degradation capacity . Denaturing gradient gel electrophoresis (DGGE) profiles of the PCR-amplified region of 16S rDNA genes were used to identify dominant bacterial populations in the fumigant-degrading soil . The DGGE results indicated that specific bacterial types had been enriched, and a more diverse fingerprint was observed in the community derived from the compost-amended soil compared with the unamended soil . Fragments from 16 different DGGE bands were cloned, sequenced and compared with published 16S rDNA sequences . Two clones, designated E1 and E4, were unique to all soils to which compost was added, and corresponded to strains of Pseudomonas and Actinomadura, respectively . CONCLUSIONS: The results show that the addition of compost to soil increases specific microbial populations and results in the accelerated degradation of fumigants . SIGNIFICANCE AND IMPACT OF THE STUDY: Application of compost manure to soil can help degrade soil fumigants at a faster rate.

Water Sci Technol, 2001, 44(4), 89 - 95
Production and oxidation of methane at low temperature by the microbial population of municipal sludge checks situated in north-east Europe; Nozhevnikova AN et al.; Methanogenic and methane-oxidizing activities of the microbial population of sewage sludge checks (Moscow and Syktyvkar regions) were studied at temperatures ranging from 5 to 25 degrees C . The number of methanogens in silt samples reached 10(10) cells/ml . A temperature decrease from 25 to 5 degrees C led to a sharp decrease of methanogenesis in the silt samples . Nevertheless, methanogenesis was still significant even at 5 degrees C . Different organic substrates, including polymeric and aromatic compounds, were degraded with methane production at 6 degrees C . At depths of 20-40 cm the number of methanotrophic bacteria reached 10(11) cells/ml . Methane oxidative activity of the microbial populations in the silt was less sensitive to the 25 degrees to 5 degrees C temperature decrease . Ten methanotrophic species, able to grow at 6 degrees C, were enriched from the Syktyvkar sludge lagoon and identified by indirect immunofluorescence . Enrichments obtained from the Syktuvkar region (62 N) contained more species of methane oxidizing bacteria able to grow at low temperature then methanogenic enrichments obtained from Moscow region (56 N).

Nature, 2001 Sep 27, 413(6854), 409 - 13
Photochemical cycling of iron in the surface ocean mediated by microbial iron(III)-binding ligands; Barbeau K et al.; Iron is a limiting nutrient for primary production in large areas of the oceans . Dissolved iron(III) in the upper oceans occurs almost entirely in the form of complexes with strong organic ligands presumed to be of biological origin . Although the importance of organic ligands to aquatic iron cycling is becoming clear, the mechanism by which they are involved in this process remains uncertain . Here we report observations of photochemical reactions involving Fe(III) bound to siderophores--high-affinity iron(III) ligands produced by bacteria to facilitate iron acquisition . We show that photolysis of Fe(III)-siderophore complexes leads to the formation of lower-affinity Fe(III) ligands and the reduction of Fe(III), increasing the availability of siderophore-bound iron for uptake by planktonic assemblages . These photochemical reactions are mediated by the alpha-hydroxy acid moiety, a group which has generally been found to be present in the marine siderophores that have been characterized . We suggest that Fe(III)-binding ligands can enhance the photolytic production of reactive iron species in the euphotic zone and so influence iron availability in aquatic systems.

J Biol Chem, 2001 Nov 30, 276(48), 44641 - 6 Epub 2001 Sep 25.
Butyrate suppression of colonocyte NF-kappa B activation and cellular proteasome activity; Yin L et al.; Butyrate is derived from the microbial metabolism of dietary fiber in the colon where it plays an important role in linking colonocyte turnover and differentiation to luminal content . In addition, butyrate appears to have both anti-inflammatory and cancer chemopreventive activities . Using confocal microscopy and cell fractionation studies, butyrate pretreatment of a human colon cell line (HT-29 cells) inhibited the tumor necrosis factor-alpha (TNF-alpha)-induced nuclear translocation of the proinflammatory transcription factor NF-kappaB . Butyrate inhibited NF-kappaB DNA binding within 30 min of TNF-alpha stimulation, consistent with an inhibition of nuclear translocation . IkappaB.NF-kappaB complexes extracted from butyrate-treated cells were relatively resistant to in vitro dissociation by deoxycholate, suggesting a change in cellular IkappaB composition . Butyrate treatment increased p100 expression, an IkappaB that was not degraded upon TNF-alpha treatment . Butyrate also reduced the extent of TNF-alpha-induced IkappaB-alpha degradation and enhanced the presence of ubiquitin-conjugated IkappaB-alpha . The suppression of IkappaB-alpha degradation corresponded with a reduction in cellular proteasome activity as determined by in vitro proteasome assays and the increased presence of ubiquitin-conjugated proteins . The butyrate suppression of IkappaB-alpha degradation and proteasome activity may derive from its ability to inhibit histone deacetylases since the specific deacetylase inhibitor trichostatin A had similar effects . These results suggest a potential mechanism for the anti-inflammatory activity of butyrate and demonstrate the interplay between short chain fatty acids and cellular proteasome activity.

Chemosphere, 2001 Oct, 45(1), 67 - 75
Effects of a non-ionic surfactant (Tween-80) on the mineralization, metabolism and uptake of phenanthrene in wheat-solution-lava microcosm; Li Y et al.; Effects of a non-ionic surfactant (Tween-80) on the mineralization, metabolism and uptake of phenanthrene in wheat-solution-lava microcosm were studied using 14C-labeled phenanthrene . The mineralization and metabolism of phenanthrene were fast in such a system . At least 90% of the applied phenanthrene were transformed within 24 days . Only 0.3% of the applied 14C-activity were identified to be the parent phenanthrene . Most of the applied 14C-activity (70%) was recovered from wheat, in which ca . 70% were associated with wheat shoots (stems and leaves) and ca . 30% wheat roots . 33% and 20% of the applied 14C-activity had been constructed into wheat tissues of shoots and roots, respectively . The 14C-activity recovered in forms of CO2 and volatile organic chemicals (VOCs) was 12-16% and 4-5%, respectively . The major metabolites of phenanthrene were polar compounds (18% of the applied 14C) and only 2.1% were identified as non-polar metabolites . No phenanthrene was found in wheat shoots indicating that it could not be transported from roots to upper parts of the plant but in form of metabolites (mostly polar metabolites) . Foliar uptake of 14C-activity via air in form of 14CO2 occurred . The presence of Tween-80 significantly enhanced the degradation of phenanthrene, which could be attributed to its increase of microbial activities in the system . Tween-80 also significantly (P < 0.05) reduced the phenanthrene level in wheat roots, which probably resulted from desorption of phenanthrene from root surface caused by the surfactant.

J Ind Microbiol Biotechnol, 2001 Jun, 26(6), 383 - 6
Enzyme treatment to reduce solids and improve settling of sewage sludge; Parmar N et al.; The effect of microbial enzymes in reducing the disposable solid content of sludge was investigated . A mixture of industrial cellulase, protease, and lipase, in equal proportion by weight, reduced total suspended solids (TSS) by 30-50% and improved settling of solids . An increase in solid reduction was observed with increasing enzyme concentration . The effect of combinations of enzyme treatments indicated that two-enzyme combinations of protease and cellulase produced better solid reduction than individual enzymes and that lipase further augmented this effect . Among the individual enzymes, protease produced a more settleable sludge as compared to cellulase and lipase . Adjustment of the pH of the enzymatically treated sludge to the acidic range (pH 2-4) further improved solid reduction, and adjustment to the alkaline range (pH 10-12) improved settleability.

J Ind Microbiol Biotechnol, 2001 Jun, 26(6), 350 - 5
Control of biogenic H(2)S production with nitrite and molybdate; Nemati M et al.; The effects of the metabolic inhibitors, sodium nitrite and ammonium molybdate, on production of H(2)S by a pure culture of the sulfate-reducing bacterium (SRB) Desulfovibrio sp . strain Lac6 and a consortium of SRB, enriched from produced water of a Canadian oil field, were investigated . Addition of 0.1 mM nitrite or 0.024 mM molybdate at the start of growth prevented the production of H(2)S by strain Lac6 . With exponentially growing cultures, higher levels of inhibitors, 0.25 mM nitrite or 0.095 mM molybdate, were required to suppress the production of H(2)S . Simultaneous addition of nitrite and molybdate had a synergistic effect: at time 0, 0.05 mM nitrite and 0.01 mM molybdate, whereas during the exponential phase, 0.1 mM nitrite and 0.047 mM molybdate were sufficient to stop H(2)S production . With an exponentially growing consortium of SRB, enriched from produced water of the Coleville oil field, much higher levels of inhibitors, 4 mM nitrite or 0.47 mM molybdate, were needed to stop the production of H(2)S . The addition of these inhibitors had no effect on the composition of the microbial community, as shown by reverse sample genome probing . The results indicate that the efficiency of inhibitors in containment of SRB depends on the composition and metabolic state of the microbial community.

Appl Environ Microbiol, 2001 Oct, 67(10), 4662 - 70
Resolution of viable and membrane-compromised bacteria in freshwater and marine waters based on analytical flow cytometry and nucleic acid double staining; Gregori G et al.; The membrane integrity of a cell is a well-accepted criterion for characterizing viable (active or inactive) cells and distinguishing them from damaged and membrane-compromised cells . This information is of major importance in studies of the function of microbial assemblages in natural environments, in order to assign bulk activities measured by various methods to the very active cells that are effectively responsible for the observations . To achieve this task for bacteria in freshwater and marine waters, we propose a nucleic acid double-staining assay based on analytical flow cytometry, which allows us to distinguish viable from damaged and membrane-compromised bacteria and to sort out noise and detritus . This method is derived from the work of S . Barbesti et al . (Cytometry 40:214-218, 2000) which was conducted on cultured bacteria . The principle of this approach is to use simultaneously a permeant (SYBR Green; Molecular Probes) and an impermeant (propidium iodide) probe and to take advantage of the energy transfer which occurs between them when both probes are staining nucleic acids . A full quenching of the permeant probe fluorescence by the impermeant probe will point to cells with a compromised membrane, a partial quenching will indicate cells with a slightly damaged membrane, and a lack of quenching will characterize intact membrane cells identified as viable . In the present study, this approach has been adapted to bacteria in freshwater and marine waters of the Mediterranean region . It is fast and easy to use and shows that a large fraction of bacteria with low DNA content can be composed of viable cells . Admittedly, limitations stem from the unknown behavior of unidentified species present in natural environments which may depart from the established permeability properties with respect to the fluorescing dyes.

Appl Environ Microbiol, 2001 Oct, 67(10), 4554 - 9
Numerical analysis of grassland bacterial community structure under different land management regimens by using 16S ribosomal DNA sequence data and denaturing gradient gel electrophoresis banding patterns; McCaig AE et al.; Bacterial diversity in unimproved and improved grassland soils was assessed by PCR amplification of bacterial 16S ribosomal DNA (rDNA) from directly extracted soil DNA, followed by sequencing of ~45 16S rDNA clones from each of three unimproved and three improved grassland samples (A . E . McCaig, L . A . Glover, and J . I . Prosser, Appl . Environ . Microbiol . 65:1721-1730, 1999) or by denaturing gradient gel electrophoresis (DGGE) of total amplification products . Semi-improved grassland soils were analyzed only by DGGE . No differences between communities were detected by calculation of diversity indices and similarity coefficients for clone data (possibly due to poor coverage) . Differences were not observed between the diversities of individual unimproved and improved grassland DGGE profiles, although considerable spatial variation was observed among triplicate samples . Semi-improved grassland samples, however, were less diverse than the other grassland samples and had much lower within-group variation . DGGE banding profiles obtained from triplicate samples pooled prior to analysis indicated that there was less evenness in improved soils, suggesting that selection for specific bacterial groups occurred . Analysis of DGGE profiles by canonical variate analysis but not by principal-coordinate analysis, using unweighted data (considering only the presence and absence of bands) and weighted data (considering the relative intensity of each band), demonstrated that there were clear differences between grasslands, and the results were not affected by weighting of data . This study demonstrated that quantitative analysis of data obtained by community profiling methods, such as DGGE, can reveal differences between complex microbial communities.

Appl Environ Microbiol, 2001 Oct, 67(10), 4479 - 87
Characterization of bacterial and fungal soil communities by automated ribosomal intergenic spacer analysis fingerprints: biological and methodological variability; Ranjard L et al.; Automated rRNA intergenic spacer analysis (ARISA) was used to characterise bacterial (B-ARISA) and fungal (F-ARISA) communities from different soil types . The 16S-23S intergenic spacer region from the bacterial rRNA operon was amplified from total soil community DNA for B-ARISA . Similarly, the two internal transcribed spacers and the 5.8S rRNA gene (ITS1-5.8S-ITS2) from the fungal rRNA operon were amplified from total soil community DNA for F-ARISA . Universal fluorescence-labeled primers were used for the PCRs, and fragments of between 200 and 1,200 bp were resolved on denaturing polyacrylamide gels by use of an automated sequencer with laser detection . Methodological (DNA extraction and PCR amplification) and biological (inter- and intrasite) variations were evaluated by comparing the number and intensity of peaks (bands) between electrophoregrams (profiles) and by multivariate analysis . Our results showed that ARISA is a high-resolution, highly reproducible technique and is a robust method for discriminating between microbial communities . To evaluate the potential biases in community description provided by ARISA, we also examined databases on length distribution of ribosomal intergenic spacers among bacteria (L . Ranjard, E . Brothier, and S . Nazaret, Appl . Environ . Microbiol . 66:5334-5339, 2000) and fungi.

Biochemistry, 2001 Oct 2, 40(39), 11651 - 9
Aminoacyl-S-enzyme intermediates in beta-hydroxylations and alpha,beta-desaturations of amino acids in peptide antibiotics; Chen H et al.; Many of the alpha-amino acids found in proteins are shunted into microbial secondary metabolism to form peptide antibiotics by specific oxidation, including hydroxylation, at the beta carbon . Examples for the enzymatic hydroxylation of tyrosine and histidine and for desaturation of proline during covalent attachment as aminoacyl-S-pantetheinyl enzyme intermediates suggest a general strategy in peptide antibiotic biosynthesis.

J Pediatr Gastroenterol Nutr, 2001 Aug, 33(2), 133 - 8
T cells of the colonic mucosa in patients with infantile colitis; Ormala T et al.; BACKGROUND: Infantile colitis is a heterogeneous group of disorders, including enterocolitis complicating Hirschsprung disease, allergic colitis, inflammatory bowel disease, and Behcet syndrome . There are limited data concerning the immune responses induced by the inflammation of the intestine in young infants . METHODS: Twenty-four colonic biopsy specimens from 12 infantile colitis patients and 12 age-matched control patients were studied by immunohistologic methods . The authors compared the T cells, their subsets expressing the surface antigens CD8 and CD4, and T-cell receptors alphabeta and deltagamma, and densities of mononuclear and epithelial cells expressing human leukocyte antigen class II antigens . RESULTS: The density of CD3+ intraepithelial lymphocytes (IELs) in the large intestinal specimens was significantly higher (P = 0.036) in colitis patients than in the control group . The majority of the CD3+ IELs were CD8+-expressing cells, and only a minority were CD4+ cells in both groups . T-cell receptors alphabeta+ (P = 0.023) and deltagamma+ (P = 0.027) IELs were observed significantly more frequently in colitis patients than in the control group . In surface epithelium, delta non-disulphide-linked type T-cell receptor (deltaTCS1) IELs were found strikingly more frequently (P = 0.001) in the specimens taken from the colitis patients . Also, the density of the deltaTCS1+ cells in crypts of the large intestine was significantly higher in colitis patients than in the control patients (P = 0.047) . CONCLUSIONS: A significant increase of CD3+ lymphocytes in the colonic epithelium of the patients with infantile colitis was noted . This increase involved both T-cell receptor alphabeta-positive and deltagamma-positive IELs . The finding of this study supports the proposal that intraluminal antigens, either microbial or food derived, are important in the pathogenesis of colitis in young infants.

J Biosci, 2001 Sep, 26(3), 349 - 55
Pancreatic islet-cell viability, functionality and oxidative status remain unaffected at pharmacological concentrations of commonly used antibiotics in vitro; Shewade Y et al.; Environmental factors such as diet, physical activity, drugs, pollution and life style play an important role in the progression and/or precipitation of diseases like diabetes, hypertension, obesity and cardiovascular disorders . Indiscriminate use of antibiotics to combat infectious diseases is one of the commonest forms of misuse of drugs . Antibiotics seem to have a correlation with diabetes and pancreatic function . There are controversial reports about the effect of antibiotics on the pancreatic islets; some suggesting their harmless action, some depicting a beneficial role and others indicating deleterious effect . Moreover, use of antibiotics is mandatory during islet isolation and cultivation to reduce incidences of microbial contamination . It is likely that antibiotic treatment may adversely affect islet viability and its functioning leading to failure of islet transplantation . The present in vitro study was undertaken to examine the effect of commonly used antibiotics such as gentamycin, penicillin, streptomycin, tetracycline, neomycin, erythromycin and chloramphenicol on islet viability, its functioning and induction of oxidative stress if any . The viability and insulin production data showed that none of the antibiotics used in the present study affect the viability and the functioning of the islets at their pharmacological concentrations . Free radical levels measured in terms of melonyldialdehyde (MDA), nitric oxide (NO) and reduced glutathione (GSH) reveal that except for a marginal increase in lipid peroxidation with tetracycline and slight increase in NO levels with streptomycin, none of these antibiotics affect the oxidative status of the cells . Antioxidant enzymes such as superoxide dismutase and catalase remain unaffected after this treatment . Our results reveal the innocuous nature of the antibiotics used at pharmacological concentrations, suggesting their safety whenever prescribed to combat infections and also during islet isolation procedures.

Biofactors, 2001, 14(1-4), 255 - 60
The green technology of selenium phytoremediation; Banuelos GS; Selenium toxicity is encountered in arid and semi-arid regions of the world with alkaline, seleniferous soils derived from marine sediments . Once present in soils and waters at high concentrations, Se is very complicated and highly expensive to remove with conventional physical and chemical techniques . Phytoremediation is a plant-based technology that is being considered for managing Se in central California soils . The technology involves the use of plants in conjunction with microbial activity associated with the plants to extract, accumulate, and volatilize Se . Once absorbed by plant roots, Se is translocated to the shoot where it may be harvested and removed from the site . Therefore, plant species used for phytoremediation of Se-laden soils may by plant uptake and volatilization minimize the Se load eventually entering agricultural effluent and the harvested crop can be carefully blended with animal forage and fed to animals in Se-deficient areas.

RNA, 2001 Sep, 7(9), 1310 - 6
Evaluation and refinement of tmRNA structure using gene sequences from natural microbial communities; Kelley ST et al.; DNA harvested directly from complex natural microbial communities by PCR has been successfully used to predict RNase P RNA structure, and can potentially provide an abundant source of information for structural predictions of other RNAs . In this study, we utilized genetic variation in natural communities to test and refine the secondary and tertiary structural model for the bacterial tmRNA . The variability of proposed tmRNA secondary structures in different organisms and the lack of any predicted tertiary structure suggested that further refinement of the tmRNA could be useful . To increase the phylogenetic representation of tmRNA sequences, and thereby provide additional data for statistical comparative analysis, we amplified, sequenced, and compared tmRNA sequences from natural microbial communities . Using primers designed from gamma proteobacterial sequences, we determined 44 new tmRNA sequences from a variety of environmental DNA samples . Covariation analyses of these sequences, along with sequences from cultured organisms, confirmed most of the proposed tmRNA model but also provided evidence for a new tertiary interaction . This approach of gathering sequence information from natural microbial communities seems generally applicable in RNA structural analysis.

J Perinat Med, 2001, 29(4), 308 - 16
A role for the 72 kDa gelatinase (MMP-2) and its inhibitor (TIMP-2) in human parturition, premature rupture of membranes and intraamniotic infection; Maymon E et al.; OBJECTIVE: Degradation of the extracellular matrix in fetal membranes has been implicated in the process of parturition and rupture of membranes . Matrix metalloproteinases (MMPs) are enzymes capable of degrading extracellular matrix including collagen . Tissue inhibitors of matrix metalloproteinases (TIMPs) inhibit the activity of MMPs by covalently binding to the enzymes . MMP-2 degrades Type IV collagen and TIMP-2 is its specific inhibitor . The objective of this study was to determine if human parturition, rupture of membranes (term and preterm) and microbial invasion of the amniotic cavity (MIAC) are associated with changes in the concentrations of MMP-2 and TIMP-2 in amniotic fluid . STUDY DESIGN: A cross-sectional study was conducted with women in the following categories: 1) term with intact membranes, in labor and not in labor; 2) preterm labor and intact membranes who delivered at term, who delivered preterm and preterm labor with MIAC; 3) preterm premature rupture of membranes (PROM) with and without infection; 4) term and preterm PROM not in labor; and 5) midtrimester . MMP-2 and TIMP-2 concentrations in amniotic fluid were determined using sensitive and specific immunoassays . RESULTS: The concentration of TIMP-2 increased with advancing gestational age (r = 0.6, p < 0.001) . No correlation was found between MMP-2 concentrations and gestational age . Human parturition and rupture of membranes (term and preterm) and in patients with intact membranes were not associated with changes in the amniotic fluid MMP-2 concentrations . In contrast, 1) patients with spontaneous labor (term and preterm) had significantly lower median concentrations of TIMP-2 compared to those not in labor (p < 0.05 for both); 2) MIAC in women with preterm labor and preterm PROM was associated with a significant decrease in amniotic fluid TIMP-2 concentrations (p < 0.04 for both comparisons); 3) Rupture of the membranes (term and preterm) was also associated with a significant decrease in the amniotic fluid TIMP-2 concentrations (p < 0.05 and p < 0.03, respectively) . CONCLUSIONS: Human parturition (preterm and term), rupture of fetal membranes (term and preterm) and intraamniotic infection are associated with a significant decrease in amniotic fluid TIMP-2 concentrations.

Clin Infect Dis, 2001 Oct 15, 33(8), 1302 - 8 Epub 2001 Sep 14.
Relationship between skin microbial counts and surgical site infection after neurosurgery; Cronquist AB et al.; A prospective study was performed to describe the density of bacterial counts on the skin of neurosurgical patients and examine the association between total colony-forming unit (cfu) counts of skin flora at the operative site and surgical site infection (SSI) . Two skin cultures were obtained, immediately before and after skin preparation, from the operative sites of 609 neurosurgical patients . SSI surveillance that used Centers for Disease Control/National Nosocomial Infection Surveillance definitions was performed . Predictors for high bacterial counts and SSI among craniotomies were analyzed by means of logistic regression . Neither pre- nor postpreparation counts were associated with SSI . Other SSI risk factors were obesity (relative risk {RR}, 2.5), duration of surgery (RR, 1.3 for every additional 30 minutes) and age (RR, 0.7 for each additional 10 years) . Duration of skin preparation was not correlated with postpreparation cfu counts . We were unable to detect an association between preoperative bacterial skin counts and SSI.

Nature, 2001 Sep 20, 413(6853), 299 - 302
The rhythm of microbial adaptation; Gerrish P; The evolutionary biologist "studies the steps by which the miraculous adaptations so characteristic of every aspect of the organic world have evolved" . But the general nature of such adaptive steps is still unclear . Evolution is often thought to be random and dependent on unpredictable events . In this light, one might expect the steps taken by adaptation to be completely random, both biologically and temporally . Here I present a mathematical derivation to show that, on the contrary, adaptive steps can have fairly strong rhythm . I find that the strength of the adaptive rhythm, that is its relative temporal regularity, is equal to a constant that is the same for all microbial populations . As a consequence, numbers of accumulated adaptations are predicted to have a universal variance/mean ratio . The theory derived here is potentially applicable to the study of molecular evolution.

Bioresour Technol, 2001 Nov, 80(2), 93 - 9
Crop residue addition effects on myriad forms and sorption of phosphorus in a Vertisol; Reddy DD et al.; Crop residues are a vital organic resource and their extensive use in soil management for sustainable agriculture is widely advocated . The effects of soybean residue (SR) and wheat residue (WR) applied alone or in combination with fertilizer P (FP) on dynamics of labile P, distribution of P fractions and P sorption in a Vertisol (Typic Haplustert) were assessed in a 16 week long incubation study . The amount of P added through crop residues, FP or their combination was kept constant at 10 mg P kg(-1) soil . Addition of SR or WR resulted in net increase of labile inorganic (Pi) and organic (Po) P, and microbial P throughout the incubation period, except that the WR decreased labile Pi during the first two weeks due to Pi immobilization . Integration of FP with SR had no added benefit compared to SR alone, while use of FP + WR proved better in ensuring short-term P availability by offsetting initial P immobilization associated with WR alone . Sequential fractionation of soil P at the end of 16 weeks showed that addition of SR and WR alone or in combination with FP favoured a build-up in labile Pi and Po (NaHCO3-Pi and Po), and moderately labile Po (NaOH-Po) fractions at the expense of recalcitrant P (HCl-P) . The P sorption capacity of soil and P required to maintain optimum solution P concentration of 0.2 mg P 1(-1) also decreased with addition of these crop residues . The implication of the results of this study is that soybean and wheat residues can potentially improve soil P fertility by increasing labile Pi and Po, and moderately labile Po fractions, decreasing P sorption and concomitantly causing dissolution of recalcitrant P in soil.

Bioresour Technol, 2001 Nov, 80(2), 101 - 9
In vitro nitrogen fixation, phosphate solubilization, survival and nutrient release by Azotobacter strains in an aquatic system; Garg SK et al.; In vitro nitrogen fixation, phosphate solubilization, survival and nutrient release by the three strains of Azotobacter (Mac-27, nitrogen fixer; PS-21, phosphate solubilizer and MSX-9, a phytohormone producer) in an aquatic system using three different organic substrates (cow-dung, piggery and poultry waste/excreta) were studied . It was shown that Azotobacter can grow and multiply in an aquatic system when fertilized either with cow-dung (100 mg 1(-1)), poultry (50 mg 1(-1)) or piggery (25 mg 1(-1)) waste/ excreta . Mac-27 and MSX-9 strains of Azotobacter fixed higher quantities of nitrogen (0.03-0.12 mg 1(-1) d(-1)) in aquaria water treated with cow-dung, while with poultry and piggery excreta, the three strains of Azotobacter fixed 0.03-0.09 mg 1(-1)d(-1) of nitrogen . O-PO4 concentration was also high in microbial-inoculated aquaria as compared to the controls which decreased with respect to time . Similarly, a decrease in total nitrogen concentration was also observed in the aquaria water after the maximum levels of fixation had been reached . Concomitant with the decrease in total nitrogen concentration, a simultaneous increase in NO3-N, NO2-N and NH4-N was observed . Maximum phytoplankton population was observed in MSX-9, while the population of zooplankton was maximum in Mac-27 inoculated aquaria . These studies indicated that Azotobacter can be used as a biofertilizer for enhancing nitrogen input and phosphate solubilization in fish ponds . Microbial inoculation along with organic substrate, however, has to be repeated at least at biweekly intervals.

J Food Prot, 2001 Sep, 64(9), 1420 - 4
Inhibition of Saccharomyces cerevisiae by slow release of propyl paraben from a polymer coating; Chung D et al.; The inhibition of Saccharomyces cerevisiae by slow release of propyl paraben from a styrene-acrylate copolymer coating was examined and compared with the inhibition by direct addition of propyl paraben . Under slow release condition, a slow but continuous microbial inhibition was observed, whereas a cell outgrowth was observed under direct addition condition after a sufficient incubation time . S . cerevisiae cells isolated from the culture under direct addition condition were more tolerant of propyl paraben than cells isolated from the culture under slow release condition . The equilibrium propyl paraben concentrations under both conditions were 150 ppm . The release kinetics of propyl paraben from the coating at 30 degrees C was found to be controlled by Fickian diffusion within the coating . The estimated partition and diffusion coefficients were 4.65 x 10(-3) and 2.01 x 10(-10) cm2/s, respectively.

J Food Prot, 2001 Sep, 64(9), 1392 - 8
A real-time approach to detect seal defects in food packages using ultrasonic imaging; Shah NN et al.; The microbial integrity of many types of flexible food packages depends on a zero defect level in the fused seam seal . Human inspection for defects in these seals is marginal at best, and secondary incubation protocols are often used to spot packages with compromised integrity before releasing product for sale . A new type of inspection method has been developed and is being evaluated for robustness . The purpose of the study was to evaluate a new raster scanning geometry to simulate continuous motion, online ultrasonic inspection of the seal region in flexible food package seals . A principal engineering tradeoff of scanning inspection systems is between increased line speed that results from decreased spatial sampling (less acquired data to process) and decreased image quality . The previously developed pulse-echo Backscattered Amplitude Integral (BAI) mode imaging technique is used to form ultrasound images using the new scanning geometry . At an ultrasonic frequency of 22.9 MHz, 38- and 50-microm-diameter air-filled channel defects in all-plastic transparent trilaminate are evaluated . The contrast-to-noise ratio (CNR) of the processed BAI-mode image is used to quantify image quality as a function of spatial sampling . Results show seal defects (38- and 50-microm diameter) are still detectable for undersampled conditions, although image quality degrades as spatial sampling decreases . Further, it is concluded that the raster scanning geometry is feasible for online inspection.

Water Environ Res, 2001 Mar-Apr, 73(2), 173 - 84
Modeling of soluble microbial products in anaerobic digestion: the effect of feed strength and composition; Barker DJ et al.; Continuously stirred tank reactors (CSTRs) and fill-and-draw reactors were used to investigate soluble microbial product (SMP) production during anaerobic digestion . Continuously stirred tank reactors with a glucose feed at three different strengths (5, 10, and 20 g chemical oxygen demand {COD}/L) and fill-and-draw reactors with four different feed compositions (glucose, glycerol, lactic acid, and starch at 10 g COD/L) were used with a solids retention time (SRT) of 15 days . The SMP production ranged from 102 to 588 mg COD/L for the glucose-fed CSTRs and between 157 and 1192 mg COD/L for the fill-and-draw reactors and was found to increase with increasing influent COD (SO) . Normalized production of SMPs (SMP/So) ranged from 1.4 to 3% for the CSTRs and 12.0, 1.7, 14.7, and 3.6% for the glucose-, glycerol-, lactic acid-, and starch-fed reactors, respectively . A model incorporating SMP production and degradation was fitted to results from carbon-14 tracer studies in all of the reactors . The best-fit parameters from this model revealed that the type of SMP that dominates in any particular system depends not only on the strength of the feed but also on the composition of the feed and the type of reactor.

Bioconjug Chem, 2001 Sep-Oct, 12(5), 750 - 6
Prolonged in vivo residence times of antibody fragments associated with albumin; Smith BJ et al.; Antibody fragments can be expressed at a high level in microbial systems, but they may have limited therapeutic value because they are rapidly eliminated from the body . We demonstrate here that site-specific conjugation or binding of bacterially derived Fab' to the long-lived protein serum albumin allows full retention of the antibody's binding characteristics while imparting the albumin's longevity in vivo . In rats the area under the curve for Fab' conjugated to rat serum albumin was 17-fold greater than for the control of Fab' conjugated to cysteine . Again, a bispecific F(ab')(2) with specificity for rat serum albumin showed an area under the curve about 8-fold greater than did a F(ab')(2) without specificity to albumin . Genetic fusions of scFv to albumin were similarly long-lived and could be expressed in yeast to provide the basis of a cost-effective production system.

Bioconjug Chem, 2001 Sep-Oct, 12(5), 701 - 10
Further studies on the site-specific protein modification by microbial transglutaminase; Sato H et al.; A guinea pig liver transglutaminase (G-TGase)-mediated procedure for the site-specific modification of chimeric proteins was recently reported . Here, an alternative method with advantages over the recent approach is described . This protocol utilizes a microbial transglutaminase (M-TGase) instead of the G-TGase as the catalyst . M-TGase, which has rather broad structural requirements as compared to the G-TGase, tends to catalyze an acyl transfer reaction between the gamma-carboxamide group of a intact protein-bound glutamine residue and various primary amines . To demonstrate the applicability of the M-TGase-catalyzed protein modification in a drug delivery system, we have utilized recombinant human interleukin 2 (rhIL-2) as the target protein and two synthetic alkylamine derivatives of poly(ethyleneglycol) (PEG12; MW 12 kDa) and galactose-terminated triantennary glycosides ((Gal)(3))) as the modifiers . For the M-TGase-catalyzed reaction with PEG12 and (Gal)(3), 1 mol of alkylamine was incorporated per mole of rhIL-2, respectively . Peptide mapping of (Gal)(3)-modified rhIL-2 ((Gal)(3)-rhIL-2) by liquid chromatography-electrospray ionization mass spectrometry (LC-ESI/MS) suggested that the Gln74 residue in rhIL-2 was site specifically modified with (Gal)(3) . The PEG12-rhIL-2 and (Gal)(3)-rhIL-2 conjugates retained full bioactivity relative to the unmodified rhIL-2 . In pharmacokinetic studies, PEG12-rhIL-2 was eliminated more slowly from the circulation than rhIL-2, whereas (Gal)(3)-rhIL-2 accumulated in the liver via hepatic asialoglycoprotein receptor binding . The results of this study expand the applicability of the TGase-catalyzed methodology for the preparation of protein conjugates for clinical use.

J Biol Chem, 2001 Nov 16, 276(46), 43010 - 7 Epub 2001 Sep 17.
A novel carbohydrate-binding protein is a component of the plant cell wall-degrading complex of Piromyces equi; Freelove AC et al.; The recycling of photosynthetically fixed carbon by the action of microbial plant cell wall hydrolases is a fundamental biological process that is integral to one of the major geochemical cycles and, in addition, has considerable industrial potential . Enzyme systems that attack the plant cell wall contain noncatalytic carbohydrate-binding modules (CBMs) that mediate attachment to this composite structure and play a pivotal role in maximizing the hydrolytic process . Anaerobic fungi that colonize herbivores are the most efficient plant cell wall degraders known, and this activity is vested in a high molecular weight complex that binds tightly to the plant cell wall . To investigate whether plant cell wall attachment is mediated by noncatalytic proteins, a cDNA library of the anaerobic fungus Piromyces equi was screened for sequences that encode noncatalytic proteins that are components of the cellulase-hemicellulase complex . A 1.6-kilobase cDNA was isolated encoding a protein of 479 amino acids with a M(r) of 52548 designated NCP1 . The mature protein had a modular architecture comprising three copies of the noncatalytic dockerin module that targets anaerobic fungal proteins to the cellulase-hemicellulase complex . The two C-terminal modules of NCP1, CBM29-1 and CBM29-2, respectively, exhibit 33% sequence identity with each other but have no homologues in protein data bases . A truncated form of NCP1 comprising CBM29-1 and CBM29-2 (CBM29-1-2) and each of the two individual copies of CBM29 bind primarily to mannan, cellulose, and glucomannan, displaying the highest affinity for the latter polysaccharide . CBM29-1-2 exhibits 4-45-fold higher affinity than either CBM29-1 or CBM29-2 for the various ligands, indicating that the two modules, when covalently linked, act in synergy to bind to an array of different polysaccharides . This paper provides the first report of a CBM-containing protein from an anaerobic fungal cellulase-hemicellulase complex . The two CBMs constitute a novel CBM family designated CBM29 whose members exhibit unusually wide ligand specificity . We propose, therefore, that NCP1 plays a role in sequestering the fungal enzyme complex onto the plant cell wall.

J Antibiot (Tokyo), 2001 Jul, 54(7), 582 - 7
An efficient screening approach for anti-Microcystis compounds based on knowledge of aquatic microbial ecosystem; Imamura N et al.; To improve the efficiency of screening for anti-Microcystis compounds, we planned to use algae-lysing bacteria that kill the organisms of water blooms . A two step-screening process was carried out, i.e., the screening of algae-lysing bacteria and the selection of anti-Microcystis producers from the bacteria . Sources for the isolation of the bacteria were a co-cultivated fluid of a water sample with axenic Microcystis viridis, a water sample collected in a water bloom season, and a water bloom sample . The water bloom sample was the best source for the isolation of the algae-lysing bacteria and such bacteria were shown to exhibit potent activity . Seventeen strains out of 20 isolated algae-lysing bacteria produced anti-Microcystis activities, and one of the principles was the previously reported argimicin A . These results indicate that algae-lysing bacteria in water blooms may be good sources for potent and selective anticyanobacterial compounds.

J Agric Food Chem, 2001 Sep, 49(9), 4171 - 6
Analysis of beta-lactam antibiotics in incurred raw milk by rapid test methods and liquid chromatography coupled with electrospray ionization tandem mass spectrometry; Riediker S et al.; A recently developed confirmatory LC-MS method has been applied to the quantification of five major beta-lactam antibiotics in suspect raw bovine milk samples that gave a positive response with receptor-based (BetaStar) and rapid microbial inhibitory screen tests (Delvotest SP) . In total, 18 presumptive positive raw milk samples were reanalyzed; 16 samples showed traces of antibiotic residues that could be identified and quantified by the LC-MS method, ranging from the limits of confirmation up to 38 microg/kg . Of the positive samples, only five (approximately 30%) were found to be violative of EU maximum residue limits . The most frequently detected antibiotic residues were cloxacillin and penicillin G, the former often in combination with amoxicillin or ampicillin . This study compares the results obtained by the three methods on identical samples and addresses how these relate to certain criteria such as sensitivity and selectivity . Furthermore, the limitations of the LC-MS method and the potential impact of the presence of frequently more than one residue in the same milk sample on the response of the rapid test methods are discussed.

Mikrobiologiia, 2001 Jul-Aug, 70(4), 558 - 66
{The effect of tillage and mesoreief on the structure of soil microbial biomass}; Sveshnikova AA et al.; The investigation of soil microbial cenoses in cultivated catenas and in virgin soils at the foot of catenas showed that the structure of these microbiocenoses depends on the type of the vegetation cover, the characteristics of mesorelief, and the degree of soil tillage . The microbiocenoses were found to be dominated by the fungal mycelium . The proportion of bacteria and fungal spores was higher and the seasonal variations in the soil microbial communities were more distinct in the cultivated than in the virgin swamp and forest soils . The type of mesorelief was found to appreciably influence microbial populations in the top humus-rich horizons of the cultivated soils and not in the mineral soil horizons.

Rapid Commun Mass Spectrom, 2001, 15(18), 1735 - 42
Investigation of atrazine metabolism in river sediment by high-performance liquid chromatography/mass spectrometry; Takats Z et al.; Microbial degradation processes play an important role in chemical water clearance taking place in river sediments . Bacteria remove not only easily degradable organic species, but various xenobiotics as well, producing clear and xenobiotic free water for bank-filtered wells . Atrazine is a widely used herbicide, and it is one of the most common xenobiotics present in Danube water . In this study the pathway and kinetics of atrazine metabolism of sedimental microbiota were studied . Samples were collected from river sediment and from pure microbial growth cultures . An analytical scheme including sample preparation, chromatography and mass spectrometry was developed and optimised . Solid-phase extraction (SPE) was found to be satisfactory for sample preparation . For qualitative analysis of samples both reversed-phase and normal-phase high-performance liquid chromatography/mass spectrometry (HPLC/MS) methods were developed and used . Selectivity, detection limits and accuracy of the two methods were compared . Using this analytical scheme, the full atrazine metabolism of the organism Comamonas acidovorans was explored . Altogether, 12 metabolites were identified from the original compound to the urea end product . Detection limits in the range of 50 ng L(-1)-1 microg L(-1) were obtained for different metabolites .

Lab Invest, 2001 Sep, 81(9), 1275 - 88
Specific deficiency in nuclear factor-kappaB activation in neurons of the central nervous system; Jarosinski KW et al.; The expression and activation of nuclear factor-kappaB (NF-kappaB) in neurons and glia of the central nervous system (CNS) has been intensely investigated because of its potential importance in understanding how this multifunctional transcription factor controls developmental and pathological processes . In particular, there has been interest in how NF-kappaB may be differentially regulated in these two major functional subgroups of cells in the CNS to provide for specific responses to various stimuli . Of special interest are responses to both proinflammatory cytokines and microbial products that signal from specific cell receptors to activate NF-kappaB . In the present studies, both neurons and glia (astrocytes) in vivo expressed latent cytoplasmic NF-kappaB analyzed by immunofluorescence microscopy and electrophoretic mobility shift analysis . In vitro, neurons and astrocytes expressed comparable levels of latent NF-kappaB molecules, but NF-kappaB nuclear localization stimulated by proinflammatory cytokines or microbial products was markedly deficient in neurons . In accord with this finding, the rapid degradation of inhibitor of NF-kappaB alpha (IkappaBalpha) that is seen in astrocytes did not occur in neurons in response to these agents . However, long-term exposure to translational inhibitors resulted in IkappaBalpha decay and activation of latent NF-kappaB in neurons, indicating potential NF-kappaB activity in these cells . Analysis of NF-kappaB-responsive interferon regulatory factor-1 gene expression indicated that increased nuclear NF-kappaB in neurons had transcriptional potential . We conclude that mechanisms responsible for inducible targeting of IkappaBalpha are uniquely regulated in neurons and account for the hypo-responsiveness of these cells to signals generated during microbial infections in the CNS . Thus, modulation of signals that target IkappaBalpha degradation may be unique and a key component of specific NF-kappaB regulation in neurons.

Mol Microbiol, 2001 Sep, 41(5), 973 - 81
Nifs and Sufs in malaria; Ellis KE et al.; This review assembles data from three bodies of literature (bacterial genetics, plastid biogenesis and parasitology) that seldom have much direct cross-talk . After overcoming terminological complications to sort out microbial nifS from sufS genes, we connect a bacterial operon, recently found to be involved in iron metabolism, the formation of {Fe-S} clusters and oxidative stress to a potentially important gene (sufB) carried on the degenerate plastid genome of malaria and related parasites.

Lett Appl Microbiol, 2001 Sep, 33(3), 232 - 6
A rapid twofold dilution method for microbial enumeration and resuscitation of uninjured and sublethally injured bacteria; Kang DH et al.; AIMS: A rapid and simple method for enumerating uninjured and sublethally injured bacterial cells, the twofold dilution method (2FD), was developed and evaluated . METHODS AND RESULTS: Following twofold serial dilution of samples in a 96 well microtiter plate, double strength selective broth or nonselective broth was added to each well . For resuscitation of heat-injured (55 degrees C for 10 min) coliforms, the selective broth was added to the wells after 3 h preresuscitation time in buffered peptone water . The results of the 2FD were compared to plating methods for total and coliform plate counts from mixed cultures and beef carcass surface tissue samples . CONCLUSION: The 2FD method results were not significantly different for uninjured cells (P > 0.05) from those obtained using Petrifilm and standard plating . Correlation of the scatterplot of spread plating and 2FD indicated a high level of agreement between these two methods (R(2)=0.98 for total counts and R(2)=0.96 for coliforms from mixed cultures; R(2)=0.98 for total cell counts and R(2)=0.94 for coliforms from faeces inoculated beef carcasses) . SIGNIFICANCE AND IMPACT OF THE STUDY: The twofold dilution method recovered significantly higher numbers of heat-injured coliforms compared to conventional plating methods (P < 0.05).

Genes Cells, 2001 Sep, 6(9), 733 - 42
Roles of Toll-like receptors in innate immune responses; Takeda K et al.; Innate immunity recognizes invading micro-organisms and triggers a host defence response . However, the molecular mechanism for innate immune recognition was unclear . Recently, a family of Toll-like receptors (TLRs) was identified, and crucial roles for these receptors in the recognition of microbial components have been elucidated . The TLR family consists of 10 members and will be expanding . Each TLR distinguishes between specific patterns of microbial components to provoke innate immune responses . The activation of innate immunity then leads to the development of antigen-specific adaptive immunity . Thus, TLRs control both innate and adaptive immune responses.

Org Lett, 2001 Sep 20, 3(19), 3029 - 32
Synthetic study of macquarimicins: highly stereoselective construction of the AB-ring system; Munakata R et al.; The highly stereoselective synthesis of the AB-ring system of macquarimicins, a novel class of microbial metabolites with inhibitory activity for neutral sphingomyelinase, has been achieved . The present synthesis features the highly stereocontrolled construction of the cis-tetrahydroindan structure via the intramolecular Diels-Alder reaction of an (E,Z,E)-1,6,8-nonatriene derived from D-glyceraldehyde acetonide . Reaction: see text.

Bioresour Technol, 2001 Oct, 80(1), 9 - 17
Dynamic simulation of cyclic batch anaerobic digestion of cattle manure; Keshtkar A et al.; Cyclic batch reactors with periodical feeds and extractions, are often used in cattle manure anaerobic digestion . The dynamic behavior of this type of reactor was simulated in this study . The kinetic model developed by I . Angelidaki et al . {Biotechnol . Bioeng . 42 (1993) 159}, together with microbial growth kinetics, conventional material balances for an ideally cyclic batch reactor, liquid-gas interactions, and liquid phase equilibrium chemistry were used in this study . The model showed good agreement with the experimental data of R.I . Mackie and M.P . Bryant {Appl . Microbiol . Biotechnol . 43 (1995) 346}, and R . Borja et al . {Chem . Eng . J . 54 (1994) B9} . The effects of hydraulic retention time (HRT), organic loading rate, reactant concentrations, feeding interval, and initial conditions such as pH and ammonia concentration on process performance can be evaluated by the dynamic model . Also simulation results show that the equilibrium conditions can be considered for CO2 distribution between liquid and gas phases, especially for processes with long retention times.

Plant Mol Biol, 2001 Sep, 47(1-2), 9 - 27
Pectin: cell biology and prospects for functional analysis; Willats WG et al.; Pectin is a major component of primary cell walls of all land plants and encompasses a range of galacturonic acid-rich polysaccharides . Three major pectic polysaccharides (homogalacturonan, rhamnogalacturonan-I and rhamnogalacturonan-II) are thought to occur in all primary cell walls . This review surveys what is known about the structure and function of these pectin domains . The high degree of structural complexity and heterogeneity of the pectic matrix is produced both during biosynthesis in the endomembrane system and as a result of the action of an array of wall-based pectin-modifying enzymes . Recent developments in analytical techniques and in the generation of anti-pectin probes have begun to place the structural complexity of pectin in cell biological and developmental contexts . The in muro de-methyl-esterification of homogalacturonan by pectin methyl esterases is emerging as a key process for the local modulation of matrix properties . Rhamnogalacturonan-I comprises a highly diverse population of spatially and developmentally regulated polymers, whereas rhamnogalacturonan-II appears to be a highly conserved and stable pectic domain . Current knowledge of biosynthetic enzymes, plant and microbial pectinases and the interactions of pectin with other cell wall components and the impact of molecular genetic approaches are reviewed in terms of the functional analysis of pectic polysaccharides in plant growth and development.

Ground Water, 2001 Sep-Oct, 39(5), 760 - 7
Characterization and origin of dissolved organic carbon in Yegua ground water in Brazos County, Texas; Routh J et al.; Dissolved organic carbon (DOC) concentrations in five shallow (< 20 m) and three deeper wells (27 to 30 m) in the Eocene Yegua Formation (Brazos County in east-central Texas) ranged from 92 to 500 microns . Characterization of high, intermediate, and low molecular weight DOC fractions (HMW > 3000 amu, IMW 1000 to 3000 amu, and LMW 500 to 1000 amu) and combined neutral sugar analyses provide information on organic matter sources in the Yegua aquifers . Combined neutral sugars ranged in concentration from 0.6 to 2.7 mumol/L and comprised 0.8% to 6.7% of DOC in ground water . Glucose was the most abundant neutral sugar, followed by xylose and galactose, arabinose, mannose, rhamnose, and fucose . These combined neutral sugars were more diagenetically altered in shallow, oxic ground water as indicated by high mole % fucose + rhamnose and low neutral sugar yield . The precursors for neutral sugars are most probably angiosperm leaves, which show a similar distribution pattern of neutral sugars . Ground water DOC was depleted in 13C relative to soil-zone organic matter (OM) (-16@1000 to -19@1000) . The delta 13C values of bulk DOC and HMW DOC ranged from -24@1000 to -32@1000, whereas LMW and IMW DOC ranged from -32@1000 to -34@1000 and -16@1000 to -28@1000, respectively . This variability in delta 13C values is probably related to microbial processes and selective preservation of OM . Carbon isotope analyses in bulk and different molecular weight DOC fractions imply a predominantly C3 OM source and a low contribution of soil-zone OM to DOC.

Stem Cells, 2001, 19(5), 388 - 96
Chemokine regulation of normal and pathologic immune responses; Christopherson K 2nd et al.; Chemokines are small basic proteins that are the major mediators of all leukocyte migration . There are at least 46 distinct chemokines, and 19 chemokine receptors, making it easily the largest cytokine family . Chemokines can be both beneficial and harmful, by either stimulating an appropriate immune response to microbial invasion, or by mediating pathologic tissue destruction in many types of human disease . Chemokines have been implicated in the tissue destruction seen in autoimmune diseases, atherosclerosis, allograft rejection, and neoplasia . Chemokines also play essential roles in normal lymphocyte trafficking to primary and secondary lymphoid organs for antigen presentation and lymphocyte maturation . Chemokines also regulate hematopoietic stem and progenitor cell homing and proliferation . Therefore, it is likely that chemokines will become important targets for pharmacologic intervention in a wide variety of human diseases in the future.

Infect Immun, 2001 Oct, 69(10), 6022 - 9
CD85/LIR-1/ILT2 and CD152 (cytotoxic T lymphocyte antigen 4) inhibitory molecules down-regulate the cytolytic activity of human CD4+ T-cell clones specific for Mycobacterium tuberculosis; Merlo A et al.; Antigen-specific cytolytic CD4+ T lymphocytes control Mycobacterium tuberculosis infection by secreting cytokines and by killing macrophages that have phagocytosed the pathogen . However, lysis of the latter cells promotes microbial dissemination, and other macrophages engulf the released bacteria . Subsequently, CD4+ T-cell-mediated killing of macrophages goes on, and this persistent process may hamper control of infection, unless regulatory mechanisms maintain a subtle balance between lysis of macrophages by cytolytic CD4+ cells and activation of cytolytic CD4+ cells by infected macrophages . We asked whether inhibitory molecules expressed by CD4+ cytolytic T lymphocytes could play a role in such a balance . To this end, human CD4+ T-cell clones specific for M . tuberculosis were produced that displayed an autologous major histocompatibility complex class II-restricted lytic ability against purified protein derivative (PPD)-pulsed antigen-presenting cells . All T-cell clones expressed CD152 (cytotoxic T-lymphocyte antigen 4 {CTLA-4}) and CD85/leukocyte immunoglobulin-like receptor 1 (LIR-1)/immunoglobulin-like transcript 2 (ILT2) inhibitory receptors, but not CD94 and the killer inhibitory receptor (or killer immunoglobulin-like receptor {KIR}) p58.2 . CD3-mediated activation of the clones was inhibited in a redirected killing assay in which CD152 and CD85/LIR-1/ILT2 were cross-linked . Specific antigen-mediated proliferation of the clones was also sharply reduced when CD152 and CD85/LIR-1/ILT2 were cross-linked by specific monoclonal antibody (MAb) followed by goat anti-mouse antiserum . In contrast, blockade of the receptors by specific MAb only increased their proliferation . Production of interleukin 2 (IL-2) and gamma interferon (IFN-gamma) by the T-cell clones was also strongly reduced when CD152 and CD85/LIR-1/ILT2 were cross-linked . The lytic activity of the T-cell clones against PPD-pulsed autologous monocytes or Epstein-Barr virus-activated B cells was increased by blockade and decreased by cross-linking of the receptors . These results indicate that CD152 and CD85/LIR-1/ILT2 play a role in the regulation of the antigen-specific activity of CD4+ cytolytic T lymphocytes against PPD-presenting cells.

Environ Microbiol, 2001 Jul, 3(7), 471 - 9
Biodiversity of Geodermatophilaceae isolated from altered stones and monuments in the Mediterranean basin; Urzi C et al.; An investigation was made into the occurrence and biodiversity of Geodermatophilaceae on 78 samples of altered stone surfaces from 24 monuments and natural stones in the Mediterranean basin; it was found that the total microbial counts ranged between 0 and 10(7) cfu g(-1) dry weight . Members of the Geodermatophilaceae family were isolated from 22 of the 78 samples examined, with the incidence of Geodermatophilaceae colonies in the cultivable population ranging from 1% to 100% . The highest percentage was found in six samples of markedly deteriorated stone . Sixty-five strains randomly isolated from the plates were clustered in six different groups by amplified 16S rDNA restriction analysis (ARDRA) using five different restriction enzymes . Twenty-five strains, representing all the ARDRA haplotypes, were characterized further by partial sequencing (350-550 bp) of the 16S rDNA and by analysing 76 morphological, metabolic and physiological properties . The strains were associated with three well-separated clusters of the genera Geodermatophilus, Blastococcus and Modestobacter . On the basis of 16S rDNA sequence and ARDRA analysis, only two strains were found to be related to the two reference strains of Geodermatophilus . All the others could be grouped with Blastococcus aggregatus (19 strains) or the Antarctic species Modestobacter multiseptatus (44 strains), suggesting that it is these two groups, rather than Geodermatophilus, that tend to colonize the stone surfaces, and that Modestobacter-like strains are also found in temperate/Mediterranean climates . From the BOX-polymerase chain reaction (PCR) data, it can be seen that the Modestobacter-like strains, belonging to the most represented ARDRA haplotype (haplotype B, 34 strains), are very polymorphic and that, over a stone surface, there is a wide genetic diversity at the microsite level.

Environ Microbiol, 2001 Jul, 3(7), 431 - 9
Quantification of bacterial subgroups in soil: comparison of DNA extracted directly from soil or from cells previously released by density gradient centrifugation; Courtois S et al.; All molecular analyses of soil bacterial diversity are based on the extraction of a representative fraction of cellular DNA . Methods of DNA extraction for this purpose are divided into two categories: those in which cells are lysed within the soil (direct extraction) and those in which cells are first removed from soil (cell extraction) and then lysed . The purpose of this study was to compare a method of direct extraction with a method in which cells were first separated from the soil matrix by Nycodenz gradient centrifugation in order to evaluate the effect of these different approaches on the analysis of the spectrum of diversity in a microbial community . We used a method based on polymerase chain reaction (PCR) amplification of a 16S rRNA gene fragment, followed by hybridization of the amplified fragments to a set of specific probes to assess the phylogenetic diversity of our samples . Control parameters, such as the relationship between amount of DNA template and amount of PCR product and the influence of competing DNA on PCR amplification, were first examined . Comparison between extraction methods showed that less DNA was extracted when cells were first separated from the soil matrix (0.4 microg g(-1) dry weight soil versus 38-93 microg g(-1) obtained by in situ lysis methods) . However, with the exception of the gamma-subclass of Proteobacteria, there was no significant difference in the spectrum of diversity resulting from the two extraction strategies.

Bioorg Med Chem Lett, 2001 Sep 17, 11(18), 2499 - 502
Inhibitors of bacterial tyrosyl tRNA synthetase: synthesis of carbocyclic analogues of the natural product SB-219383; Jarvest RL et al.; Carbocyclic analogues of the microbial metabolite SB-219383 have been synthesised and evaluated as inhibitors of bacterial tyrosyl tRNA synthetase . One compound showed highly potent and selective nanomolar inhibition.

Appl Microbiol Biotechnol, 2001 Aug, 56(3-4), 315 - 25
Bacterial alginate: physiology, product quality and process aspects; Sabra W et al.; Alginate, a copolymer of beta-D-mannuronic acid and alpha-L-guluronic acid and currently commercially produced from the marine brown algae, can also be biologically produced by bacteria such as Azotobacter vinelandii, A . chroococcum and several species of Pseudomonas . The ever-increasing applications of this polymer in the food and pharmaceutical sectors have led to continuing research interest aimed at better understanding the metabolic pathways, the physiological or biological function of this polymer, the regulation of its formation and composition, and optimising the microbial production process . These aspects are reviewed here, with particular attention to alginate formation in the soil bacterium A . vinelandii . In addition, the biotechnological and industrial applications of alginate are summarised.

Water Sci Technol, 2001, 44(2-3), 351 - 8
Degradation of lignin and lignin model compound under sulfate reducing condition; Pareek S et al.; The release of depolymerization products of lignin during the degradation of lignocellulsic material under sulfate reducing condition was investigated . In addition, we investigated the fate of the most common (beta-O-4) link present in lignin under sulfate reducing condition, using a lignin model compound . The method of investigation was based on the selective inhibition of microbial uptake of released aromatic phenolic compounds, depolymerization product of lignin, by toluene . Eight different aromatic phenolic compounds were identified . Until day 17 only 3 phenolic compounds were regularly detected, thereafter 7 aromatic phenolic compounds could be regularly identified . The accumulation of identified phenolic acid was not linear with time . The lignin model compound was completely degraded within 13 days when either Avicel cellulose or newspaper was present as alternate source of carbon . On the other hand when lignin model compound was present as the sole source of carbon, it took more than 22 days for its complete degradation . But in either case complete degradation of lignin model compound was observed . Four degradation byproducts of lignin model compound were identified, but the two most significant compounds identified were vanillic acid and 3-methoxy-4-hydroxy benzene propionic acid . The GC/MS analysis of the degradation by products of lignin model compound indicated that beta-O-4 link was cleaved under sulfate reducing condition and the presence of additional carbon source enhanced this process.

J Mammary Gland Biol Neoplasia, 2001 Jul, 6(3), 253 - 73
Proteoglycans: pericellular and cell surface multireceptors that integrate external stimuli in the mammary gland; Delehedde M et al.; Proteoglycans consist of a core protein and an associated glycosaminoglycan (GAG) chain of heparan sulfate, chondroitin sulfate, dermatan sulfate or keratan sulfate, which are attached to a serine residue . The core proteins of cell surface proteoglycans may be transmembrane, e.g., syndecan, or GPI-anchored, e.g., glypican . Many different cell surface and matrix proteoglycan core proteins are expressed in the mammary gland and in mammary cells in culture . The level of expression of these core proteins, the structure of their GAG chains, and their degradation are regulated by many of the effectors that control the development and function of the mammary gland . Regulatory proteins of the mammary gland that bind GAG include many growth factors and morphogens (fibroblast growth factors, hepatocyte growth factor/scatter factor, members of the midkine family, wnts), matrix proteins (collagen, fibronectin, and laminin), enzymes (lipoprotein lipase) and microbial surface proteins . Structural diversity within GAG chains ensures that each protein-GAG interaction is as specific as necessary and a number of sequences of saccharides that recognize individual proteins have been elucidated . The GAG-protein interactions serve to regulate the signal output of growth factor receptor tyrosine kinase and hence cell fate as well as the storage and diffusion of extracellular protein effectors . In addition, GAGs clearly coordinate stromal and epithelial development, and they are active participants in mediating cell-cell and cell-matrix interactions . Since a single proteoglycan, even if it carries a single GAG chain, can bind multiple proteins, proteoglycans are also likely to act as multireceptors which promote the integration of cellular signals.

Water Res, 2001 Oct, 35(14), 3411 - 7
Microbial-ecological significance of sulfide precipitation within anaerobic granular sludge revealed by micro-electrodes study; Yamaguchi T et al.; Micro-electrodes were applied to anaerobic granular sludge, which was developed in a UASB reactor, to examine intra-granule profiles with respect to pH, glucose and sulfide . When glucose was employed as a bulk liquid substrate, the micro-electrodes study demonstrated the pH behavior along granule depth: pH decrement at the granule exterior portion due to acid formation (buildup of acidity), and subsequent pH increment at the granule inner portion due to the consumption of acid (buildup of alkalinity) . Sulfide micro-electrode proved sulfate reduction that mostly occurred at the granule exterior portion . Chemical equilibrium consideration evidently explained the occurrence of ferric sulfide predominantly in the interior portion, which accounts well for the morphology of a representative double-layered structure of granules grown on a low level of sulfite . Inorganic elements distribution within anaerobic granule was examined by electron probe X-ray micro analysis (EPMA) and ICP methods . The presence of crystalline calcium carbonate (calcite) was identified by X-ray diffraction analysis.

Med Device Technol, 2001 Apr, 12(3), 15 - 6
A new microbial barrier test for porous medical packaging materials; Fielding P; A reproducible, quick and easy-to-use test has been developed for routine evaluation and control of packaging materials.

Nat Prod Lett, 2001, 15(1), 71 - 4
Biological stereoselective reduction of 3,3,5-trimethylcyclohexanone by Glomerella cingulata; Okamura S et al.; The microbial transformation of 3,3,5-trimethylcyclohexanone was investigated using the plant pathogenic fungus, Glomerella cingulata . With this organism 3,3,5-trimethylcyclohexanone gave the corresponding cis- and trans-3,3,5-trimethylcyclohexanols with the ratio of 20:1 forming the cis-isomer highly stereoselectively, upon 5 days incubation together with 3,3,5-trimethyl-2-cyclohexen-1-one (isophrone) as a minor product.

Lethaia, 1999 Sep, 32(3), 219 - 40
Fossil preservation in the Neoproterozoic Doushantuo phosphorite Lagerstatte, South China; Xiao S et al.; Phosphorites of the late Neoproterozoic Doushantuo Formation exposed in the vicinity of Weng'an, Guizhou Province, and Chadian, Shaanxi Province, South China, contain exceptionally well-preserved algal thalli, acritarchs, and globular microfossils interpreted as animal embryos . Combined optical microscopic and SEM observations provide insights into the taphonomy of phosphatized fossils . Algal cells and tissues are variably resistant to decay, and within preserved populations permineralization began at varying stages of degradation . In consequence, there is a spectrum of quality in cellular preservation . Algal cell walls, acritarch vesicles, and embryo envelopes are commonly encrusted by an isopachous rim of apatite, with cell interiors filled by collophane and later diagenetic dolomite . In contrast, blastomere surfaces of animal embryos are encrusted primarily by minute phosphatic spherules and filaments, possibly reflecting an immediately postmortem infestation of bacteria that provided nucleation sites for phosphate crystal growth . Thus, the same processes that gave rise to Phanerozoic phosphatized Lagerstatten--phosphatic encrustation, and impregnation, probably mediated by microbial activity--effected soft-tissue preservation in the Doushantuo Lagerstatte . It remains unclear how phosphatic ions and organic macromolecules interact at the molecular level and to what extent specific microbial metabolisms or microenvironmental conditions control the phosphatization of soft tissues . New observations of phosphatized Doushantuo fossils include: a second locality (Chadian) for Wengania globosa, interpreted as an algal thallus and previously known only from Weng'an; microtunnels in Weng'an phosphorites interpreted as pyrite trails; and new taxa described from Weng'an: Meghystrichosphaeridium reticulatum (acritarch), Sarcinophycus radiatus (algal thallus), and one unnamed problematic form.

Icarus, 2000 Apr, 144(2), 210 - 42
The state and future of Mars polar science and exploration; Clifford SM et al.; As the planet's principal cold traps, the martian polar regions have accumulated extensive mantles of ice and dust that cover individual areas of approximately 10(6) km2 and total as much as 3-4 km thick . From the scarcity of superposed craters on their surface, these layered deposits are thought to be comparatively young--preserving a record of the seasonal and climatic cycling of atmospheric CO2, H2O, and dust over the past approximately 10(5)-10(8) years . For this reason, the martian polar deposits may serve as a Rosetta Stone for understanding the geologic and climatic history of the planet--documenting variations in insolation (due to quasiperiodic oscillations in the planet's obliquity and orbital elements), volatile mass balance, atmospheric composition, dust storm activity, volcanic eruptions, large impacts, catastrophic floods, solar luminosity, supernovae, and perhaps even a record of microbial life . Beyond their scientific value, the polar regions may soon prove important for another reason--providing a valuable and accessible reservoir of water to support the long-term human exploration of Mars . In this paper we assess the current state of Mars polar research, identify the key questions that motivate the exploration of the polar regions, discuss the extent to which current missions will address these questions, and speculate about what additional capabilities and investigations may be required to address the issues that remain outstanding.

Geochim Cosmochim Acta, 1999 May, 63(9), 1345 - 58
Terminal Proterozoic mid-shelf benthic microbial mats in the Centralian Superbasin and their environmental significance; Logan GA et al.; A combined sedimentological and biogeochemical study has been conducted on several Terminal Proterozoic mid-shelf microbial mat facies from the Centralian Super-basin . Isotopic and organic geochemical analysis of the bitumen and kerogen indicated that two sources of organic matter from 'planktonic' and 'benthic microbial-mat' populations contributed to the sediment . The 'planktonic' source provided a suite of n-alkanes with <C20 predominance and the odd n-alkanes >C20, whereas, the 'benthic' source contributed an overlay of n-alkanes >C20 with a strong even preference, together with mid-chain methyl alkanes . Kerogen and biomarkers derived from the microbial mat were found to be depleted in 13C relative to planktonic material . Pyrite in the microbial mats was also found to be depleted in 34S compared to surrounding facies . The combination of these observations suggested that the mats may have been at least partly composed of sulfide oxidising bacteria . These organisms have specific environmental tolerances that set limits on palaeo-environment . Their requirement for oxygen indicates that the water column above the mid-shelf could not have been anoxic . Accordingly, from the results and age determinations reported here, it would appear that mid-shelf environments of the Centralian Superbasin of Australia were seeing significant levels of oxygen through the Ediacarian.

J Geophys Res, 1999 Nov 25, 104(E11), 26977 - 95
Exploring for a record of ancient Martian life; Farmer JD et al.; The immediate task facing exopaleontology is to define a strategy to explore Mars for a fossil record during the decade-long exploration program that lies ahead . Consideration of the quality of paleontological information preserved under different geological conditions is important if we are to develop a strategy with broad applicability . The preservation of microbial fossils is strongly influenced by the physical, chemical, and biological factors of the environment which, acting together, determine the types of information that will be captured and retained in the rock record . In detrital sedimentary systems, preservation is favored by rapid burial in fine-grained, clay-rich sediments . In chemical sedimentary systems, preservation is enhanced by rapid entombment in fine-grained chemical precipitates . For long-term preservation, host rocks must be composed of stable minerals that are resistant to chemical weathering and that form an impermeable matrix and closed chemical system to protect biosignatures from alteration during subsequent diagenesis or metamorphism . In this context, host rocks composed of highly ordered, chemically stable mineral phases, like silica (e.g., cherts) or phosphate (e.g., phosphorites), are especially favored . Such lithologies tend to have very long crustal residence times and, along with carbonates and shales, are the most common host rocks for the Precambrian microfossil record on Earth . Although we make the defensible assumption that Mars was more like the Earth early in its history, clearly, the geological and historical differences between the two planets are many . Such differences must be carefully considered when adapting an Earth-based strategy to Mars.

Limnol Oceanogr, 1998 Nov, 43(7), 1754 - 61
Viruses in Antarctic lakes; Kepner RL Jr et al.; Water samples collected from four perennially ice-covered Antarctic lakes during the austral summer of 1996-1997 contained high densities of extracellular viruses . Many of these viruses were found to be morphologically similar to double-stranded DNA viruses that are known to infect algae and protozoa . These constitute the first observations of viruses in perennially ice-covered polar lakes . The abundance of planktonic viruses and data suggesting substantial production potential (relative to bacteria} secondary and photosynthetic primary production) indicate that viral lysis may be a major factor in the regulation of microbial populations in these extreme environments . Furthermore, we suggest that Antarctic lakes may be a reservoir of previously undescribed viruses that possess novel biological and biochemical characteristics.

Annu Rev Earth Planet Sci, 1999, 27, 313 - 58
Stromatolites in Precambrian carbonates: evolutionary mileposts or environmental dipsticks?
Grotzinger JP, Knoll AH.
Stromatolites are attached, lithified sedimentary growth structures, accretionary away from a point or limited surface of initiation . Though the accretion process is commonly regarded to result from the sediment trapping or precipitation-inducing activities of microbial mats, little evidence of this process is preserved in most Precambrian stromatolites . The successful study and interpretation of stromatolites requires a process-based approach, oriented toward deconvolving the replacement textures of ancient stromatolites . The effects of diagenetic recrystallization first must be accounted for, followed by analysis of lamination textures and deduction of possible accretion mechanisms . Accretion hypotheses can be tested using numerical simulations based on modem stromatolite growth processes . Application of this approach has shown that stromatolites were originally formed largely through in situ precipitation of laminae during Archean and older Proterozoic times, but that younger Proterozoic stromatolites grew largely through the accretion of carbonate sediments, most likely through the physical process of microbial trapping and binding . This trend most likely reflects long-term evolution of the earth's environment rather than microbial communities.

Meteorit Planet Sci, 2000 Mar, 35(2), 237 - 41
Investigations into an unknown organism on the martian meteorite Allan Hills 84001; Steele A et al.; Examination of fracture surfaces near the fusion crust of the martian meteorite Allan Hills (ALH) 84001 have been conducted using scanning electron microscopy (SEM) and atomic force microscopy (AFM) and has revealed structures strongly resembling mycelium . These structures were compared with similar structures found in Antarctic cryptoendolithic communities . On morphology alone, we conclude that these features are not only terrestrial in origin but probably belong to a member of the Actinomycetales, which we consider was introduced during the Antarctic residency of this meteorite . If true, this is the first documented account of terrestrial microbial activity within a meteorite from the Antarctic blue ice fields . These structures, however, do not bear any resemblance to those postulated to be martian biota, although they are a probable source of the organic contaminants previously reported in this meteorite.

Lethaia, 1998 Sep, 31(3), 169 - 84
Multi-trichomous cyanobacterial microfossils from the Mesoproterozoic Gaoyuzhuang Formation, China: paleoecological and taxonomic implications; Seong-Joo L et al.; Populations of the multi-trichomous microbial fossil Eoschizothrix composita n.gen . et sp . are preserved in growth position in silicified stratiform stromatolites of the Gaoyuzhuang Formation, Hebei Province, northern China . The microbial fossils consist predominantly of preserved sheaths, although several specimens retain shriveled remains of trichomes within sheaths . Comparisons with modern morphological counterparts, including shape, growth habit and orientation, degradational sequences, and habitat, support the interpretation of the multi-trichomous microfossils as cyanobacteria, which acted as frame-builders of ancient stromatolites . The distribution and orientation of multi-trichomous microfossils within a synsedimentary context reveal their behavioral responses to sedimentation regime . Horizontally spread, interwoven mats formed during periods of sedimentary stasis . During periods of rapid sediment influx, the filaments assumed an upright orientation, possibly to avoid accumulating particles . This is the first record of fossil stromatolite-building multi-trichomous cyanobacterial which underscores early morphological and functional diversification in cyanobacterial evolution.

Adv Space Res, 1997, 20(10), 1913 - 22
Accumulation and effect of volatile organic compounds in closed life support systems; Stutte GW et al.; Bioregenerative life support systems (BLSS) being considered for long duration space missions will operate with limited resupply and utilize biological systems to revitalize the atmosphere, purify water, and produce food . The presence of man-made materials, plant and microbial communities, and human activities will result in the production of volatile organic compounds (VOCs) . A database of VOC production from potential BLSS crops is being developed by the Breadboard Project at Kennedy Space Center . Most research to date has focused on the development of air revitalization systems that minimize the concentration of atmospheric contaminants in a closed environment . Similar approaches are being pursued in the design of atmospheric revitalization systems in bioregenerative life support systems . in a BLSS one must consider the effect of VOC concentration on the performance of plants being used for water and atmospheric purification processes . In addition to phytotoxic responses, the impact of removing biogenic compounds from the atmosphere on BLSS function needs to be assessed . This paper provides a synopsis of criteria for setting exposure limits, gives an overview of existing information, and discusses production of biogenic compounds from plants grown in the Biomass Production Chamber at Kennedy Space Center.

Adv Space Res, 1983, 3(9), 265 - 8
Changes in symbiotic and associative interrelations in a higher plant-bacterial system during space flight; Kordyum VA et al.; The miniature cenosis consisting of the water fern Azolla with its associated symbiotic nitrogen-fixing cyanobacterium Anabaena and the concomitant bacteria was investigated . Ecological closure was shown to produce sharp quantitative and qualitative changes in the number and type of concomitant bacteria . Changes in the distribution of bacterial types grown on beef-extract broth after space flight were recorded . Anabaena azollae underwent the most significant changes under spaceflight conditions . Its cell number per Azolla biomass unit increased substantially . Thus closure of cenosis resulted in a weakening of control over microbial development by Azolla . This tendency was augmented by spaceflight factors . Reduction in control exerted by macro-organisms over development of associated micro-organisms must be taken into account in constructing closed ecological systems in the state of weightlessness.

J Gravit Physiol, 1998 Jul, 5(1), P145 - 6
Microbial and fungal contamination contributes to physical stress in space flight: studies in the Euromir-95 mission; Norbiato G et al.; Astronauts are subjected to flight-induced physical and psychic reactions which may be health threatening in the long term . Stress is a basic component of space missions, where astronauts are confined in a reduced volume, live in a hostile environment, have limited contact with the rest of the world and undergo a severe work load . Chronic stress in microgravity stimulates the HPA (hypothalamo-pituitary-adrenal) axis in astronauts with consequent hypercortisolim . Stress also stimulates the autonomic nervous system . Both increased cortisol and adrenergic stimulation suppress the immune function . For these reasons we developed experiments to contemporaneously measure the autonomic, HPA-axis and immune function in space missions . All measures are made with non-invasive methods . Autonomic adaptation is measured by spectral analysis of ECG derived interval, arterial pressure and respiration . HPA-axis function is assessed by measuring cortisol, F-Testosterone and DHEA in saliva . Immune function is monitored by measuring cytokine production and Th1/Th2 balance in saliva . Till now these experiments were performed on the ground . On 1998-99 space experiments will be performed and space technologies will be set up in collaboration with DMR company (Varese), to allow astronauts to measure stress factors directly in space . I.R.C.E.A . research, sponsored by the Italian Space Agency and selected by ESA and NASA, is focused on conditions which influence health in space flight: in particular, stress and microbial contamination . These two conditions are strictly correlated as infections causes stress and stress, by inhibiting the immune system, makes infection easier.

J Gravit Physiol, 1998 Jul, 5(1), P139 - 40
Phagocyte system under spaceflight conditions; Meshkov D et al.; The spaceflight conditions lead to disturbances in immune system and cause the changes in microbial and chemical environment that create preconditions for immunodeficiency and allergic disease development . With the spaceflights lengthening the problem of crewmembers immunodeficiency and the probability of allergic disease manifestation became actual . The higher risk of various pathological conditions noted in cosmonauts during space flight due to lowered immunological resistance and unnatural biological and chemical environment (autoimmune reactions, bacterial and viral autoinfections, possible allergic events etc.) proves the need of studying the mechanisms of these disturbances and determination the most labile links between the immune system and antigen environment . In this case phagocytes seems to be one of the most important cells that can influence both induction and effector stage of immune reactions and also take part in the regulation of the immune response . The goal of the investigation was to conduct studies of one of the of the phagocytes metabolic and migration activity that are closely connected with functional activity of the cells.

Palaios, 1995 Dec, 10(6), 578 - 96
Anomalous carbonate precipitates: is the Precambrian the key to the Permian?
Grotzinger JP, Knoll AH.
Late Permian reefs of the Capitan complex, west Texas; the Magnesian Limestone, England; Chuenmuping reef, south China; and elsewhere contain anomalously large volumes of aragonite and calcite marine cements and sea-floor crusts, as well as abundant microbial precipitates . These components strongly influenced reef growth and may have been responsible for the construction of rigid, open reefal frames in which bryozoans and sponges became encrusted and structurally reinforced . In some cases, such as the upper biostrome of the Magnesian Limestone, precipitated microbialites and inorganic crusts were the primary constituents of the reef core . These microbial and inorganic reefs do not have modern marine counterparts; on the contrary, their textures and genesis are best understood through comparison with the older rock record, particularly that of the early Precambrian . Early Precambrian reefal facies are interpreted to have formed in a stratified ocean with anoxic deep waters enriched in carbonate alkalinity . Upwelling mixed deep and surface waters, resulting in massive seafloor precipitation of aragonite and calcite . During Mesoproterozoic and early Neoproterozoic time, the ocean became more fully oxidized, and seafloor carbonate precipitation was significantly reduced . However, during the late Neoproterozoic, sizeable volumes of deep ocean water once again became anoxic for protracted intervals; the distinctive "cap carbonates" found above Neoproterozoic tillites attest to renewed upwelling of anoxic bottom water enriched in carbonate alkalinity and 12C . Anomalous late Permian seafloor precipitates are interpreted as the product, at least in part, of similar processes . Massive carbonate precipitation was favored by: 1) reduced shelf space for carbonate precipitation, 2) increased flux of Ca to the oceans during increased continental erosion, 3) deep basinal anoxia that generated upwelling waters with elevated alkalinities, and 4) further evolution of ocean water in the restricted Delaware, Zechstein, and other basins . Temporal coincidence of these processes resulted in surface seawater that was greatly supersaturated by Phanerozoic standards and whose only precedents occurred in Precambrian oceans.

Eur J Protistol, 1998 Dec 7, 34(4), 402 - 14
Acronema sippewissettensis Gen . Nov . Sp . Nov., microbial mat bicosoecid (Bicosoecales = Bicosoecida); Teal TH et al.; A heterotrophic mastigote from the flat laminated Microcoleus-dominated intertidal microbial mat at the Sippewissett salt marsh, Cape Cod, Massachusetts, was isolated into monoprotist culture in the same anoxic medium that led to spirochete and other anaerobic bacterial enrichments . The protist grew vigorously and was transferred indefinitely in oxic marine medium . Videomicroscopy as well as scanning and transmission electron microscopy were used to document its features . The swimming and perching behavior, nutritional mode (bactivory) and morphology including ultra-structure identify it as an aloricate bicosoecid . The presence of heteromorphic acronematic undulipodia, bilateral bipartite tubular mastigonemes, absence of a cytostome, absence of extrusomes, and presence of "Dauerstadien" (duration stages) distinguish this from other Cafeteriaceae bicosoecids . Cell division involves a closed intranuclear spindle . The unspecialized bicosoecid morphology and behavior juxtaposed with oomycete-like vesicles and mastigonemes suggest that this protist may be an extant descendant of a common ancestor of bicosoecids and other stramenopiles (e.g . labyrinthulids, thraustochytrids and oomycetes) . A new genus and species, Acronema sippewissettensis, are proposed.

J Phycol, 1989, 25, 655 - 61
Lipophilic pigments from cyanobacterial (blue-green algal) and diatom mats in Hamelin Pool, Shark Bay, Western Australia; Palmisano AC et al.; Lipophilic pigments were examined in microbial mat communities dominated by cyanobacteria in the intertidal zone and by diatoms in the subtidal and sublittoral zones of Hamelin Pool, Shark Bay, Western Australia . These microbial mats have evolutionary significance because of their similarity to lithfied stromatolites from the Proterozoic and Early Paleozoic eras . Fucoxanthin, diatoxanthin, diadinoxanthin, beta-carotene, and chlorophylls a and c characterized the diatom mats, whereas cyanobacterial mats contained myxoxanthophyll, zeaxanthin, echinenone, beta-carotene, chlorophyll a and, in some cases, sheath pigment . The presence of bacteriochlorophyll a within the mats suggest a close association of photosynthetic bacteria with diatoms and cyanobacteria . The high carotenoids : chlorophyll a ratios (0.84-2.44 wt/wt) in the diatom mats suggest that carotenoids served a photoprotective function in this high light environment . By contrast, cyanobacterial sheath pigment may have largely supplanted the photoprotective role of carotenoids in the intertidal mats.

Arch Hydrobiol Suppl Algol Stud, 1988 Sep, 78(4), 425 - 46
Mychonastes desiccatus Brown sp . nova (Chlorococcales, Chlorophyta)--an intertidal alga forming achlorophyllous desiccation-resistant cysts; Margulis L et al.; An intertidal Chlorella-like alga Mychonastes desiccatus Brown sp . nova, capable of forming achlorophyllous desiccation-resistant cysts, has been grown in unialgal culture . This small alga was first isolated from a dried sample of a well-studied microbial mat . The mat, located at North Pond, Laguna Figueroa, San Quintin, Baja California, Mexico, is a vertically-stratified microbial community which forms laminated sediments . Morphology, pigment composition and G+C content are within the range typical for the genus Chlorella s . 1 . Unlike other chlorellae, however, upon desiccation M . desiccatus forms an achlorophyllous, lipid-filled cyst (thick-walled resting stage) in which no plastid is evident . Rewetting leads to chloroplast differentiation, excystment and recovery of the fully green alga . During desiccation, sporopollenin is deposited within a thickening cell wall . Encystment cannot be induced by growth in the dark . The formation of desiccation-induced cysts allows the alga to survive frequent and intermittent periods of dryness . These chlorellae tolerate wide ranges of acidity and temperature; they both grow and form cysts in media in which sodium ions are replaced with potassium . Although the cysts tolerate crystalline salts, the cell grow optimally in concentrations corresponding from three-quarters to full-strength seawater.

Microbios, 1988, 55, 75 - 83
Niebla ceruchis from Laguna Figueroa: dimorphic spore morphology and secondary compounds localized in pycnidia and apothecia; Enzien M et al.; During and after the floods of 1979-80 Niebla ceruchis growing epiphytically on Lycium brevipes was one of the dominant aspects of the vegetation in the coastal dunal complex bordering the microbial mats at Laguna Figueroa, Baja California Norte, Mexico . The lichen on denuded branches of Lycium was far more extensively distributed than Lycium lacking lichen . Unusual traits of this Niebla ceruchis strain, namely localization of lichen compounds in the mycobiont reproductive structures (pycnidia and apothecia) and simultaneous presence of bilocular and quadrilocular ascospores, are reported . The abundance of this coastal lichen cover at the microbial mat site has persisted through April 1988.

Symbiosis, 1987, 4, 185 - 98
Symbiont acquisition as neoseme: origin of species and higher taxa; Bermudes D et al.; We examine the hypothesis that, in the origin of species and higher taxa of eukaryotes, symbiont acquisition followed by partner integration has been equivalent to neoseme appearance leading to speciation . The formation of stable symbiotic associations involves partner-surface recognition, behavioral and metabolic interaction, and, in some cases, gene product (RNA, protein) and genic (RNA, DNA) integration . This analysis is applied here to examples of neosemes that define specific taxa and to neosemes in plants, fungi, and animals that involve the appearance of new types of tissue . If this hypothesis is correct--if the origin of major genetic variation leading to speciation and even higher taxa may occur through symbiont acquisition and integration--then the analysis of "origins of species and higher taxa" becomes analogous to the study of microbial community ecology.

Geochim Cosmochim Acta, 1987, 51, 879 - 94
Low temperature hydrothermal maturation of organic matter in sediments from the Atlantis II Deep, Red Sea; Simoneit BR et al.; Hydrocarbons and bulk organic matter of two sediment cores (No . 84 and 126, CHAIN 61 cruise) located within the Atlantis II Deep have been analyzed . Although the brines overlying the coring areas were reported to be sterile, microbial inputs and minor terrestrial sources the major sedimentary organic material . This input is derived from the upper water column above the brines . Both steroid and triterpenoid hydrocarbons show that extensive acid-catalyzed reactions are occurring in the sediments . In comparison with other hydrothermal (Guaymas Basin) or intrusive systems (Cape Verde Rise), the Atlantis II Deep exhibits a lower degree of thermal maturation . This is easily deduced from the elemental composition of the kerogens and the absence of polynuclear aromatic hydrocarbons of a pyrolytic origin in the bitumen . The lack of carbon number preference among the n-alkanes suggests, especially in the case of the long chain homologs, that the organic matter of Atlantis II Deep sediments has undergone some degree of catagenesis . However, the yields of hydrocarbons are much lower than those observed in other hydrothermal areas . The effect of lower temperature and poor source-rock characteristics appear to be responsible for the differences.

Icarus, 1986 Oct, 68(1), 176 - 84
Amino acids derived from Titan tholins; Khare BN et al.; An organic heteropolymer (Titan tholin) was produced by continuous dc discharge through a 0.9 N2/0.1 CH4 gas mixture at 0.2 mbar pressure, roughly simulating the cloudtop atmosphere of Titan . Treatment of this tholin with 6N HCl yielded 16 amino acids by gas chromatography after derivatization of N-trifluroacetyl isopropyl esters on two different capillary columns . Identifications were confirmed by GC/MS . Glycine, aspartic acid, and alpha- and beta-alanine were produced in greatest abundance; the total yield of amino acids was approximately 10(-2), approximately equal to the yield of urea . The presence of "nonbiological" amino acids, the absence of serine, and the fact that the amino acids are racemic within experimental error together indicate that these molecules are not due to microbial or other contamination, but are derived from the tholin . In addition to the HCN, HC2CN, and (CN)2 found by Voyager, nitriles and aminonitriles should be sought in the Titanian atmosphere and, eventually, amino acids on the surface . These results suggest that episodes of liquid water in the past or future of Titan might lead to major further steps in prebiological organic chemistry on that body.

Org Geochem, 1986, 10, 1059 - 65
Long-chain carboxylic acids in pyrolysates of Green River kerogen; Kawamura K et al.; Long-chain fatty acids (C10-C32), as well as C14-C21 isoprenoid acids (except for C18), have been identified in anhydrous and hydrous pyrolyses products of Green River kerogen (200-400 degrees C, 2-1000 hr) . These kerogen-released fatty acids are characterized by a strong even/odd predominance (CPI: 4.8-10.2) with a maximum at C16 followed by lesser amounts of C18 and C22 acids . This distribution is different from that of unbound and bound geolipids extracted from Green River shale . The unbound fatty acids show a weak even/odd predominance (CPI: 1.64) with a maximum at C14, and bound fatty acids display an even/odd predominance (CPI: 2.8) with maxima at C18 and C30 . These results suggest that fatty acids were incorporated into kerogen during sedimentation and early diagenesis and were protected from microbial and chemical changes over geological periods of time . Total quantities of fatty acids produced during heating of the kerogen ranged from 0.71 to 3.2 mg/g kerogen . Highest concentrations were obtained when kerogen was heated with water for 100 hr at 300 degrees C . Generally, their amounts did not decrease under hydrous conditions with increase in temperature or heating time, suggesting that significant decarboxylation did not occur under the pyrolysis conditions used, although hydrocarbons were extensively generated.

Biol Sci Space, 1998 Jun, 12(2), 119 - 23
Search for life on Mars; Brack A et al.; A multi-user integrated suite of instruments designed to optimize the search for evidence of life on Mars is described . The package includes: -Surface inspection and surface environment analysis to identify the potential Mars landing sites, to inspect the surface geology and mineralogy, to search for visible surficial microbial macrofossils, to study the surface radiation budget and surface oxidation processes, to search for niches for extant life . -Subsurface sample acquisition by core drilling -Analysis of surface and subsurface minerals and organics to characterize the surface mineralogy, to analyse the surface and subsurface oxidants, to analyse the mineralogy of subsurface aliquots, to analyse the organics present in the subsurface aliquots (elemental and molecular composition, isotopes, chirality) . -Macroscopic and microscopic inspection of subsurface aliquots to search for life's indicators (paleontological, biological, mineralogical) and to characterize the mineralogy of the subsurface aliquots . The study is led by ESA Manned Spaceflight and Microgravity Directorate.

J Geophys Res, 1997 May 25, 102(E5), 10881 - 8
Organic degradation under simulated Martian conditions; Stoker CR et al.; We report on laboratory experiments which simulate the breakdown of organic compounds under Martian surface conditions . Chambers containing Mars-analog soil mixed with the amino acid glycine were evacuated and filled to 100 mbar pressure with a Martian atmosphere gas mixture and then irradiated with a broad spectrum Xe lamp . Headspace gases were periodically withdrawn and analyzed via gas chromatography for the presence of organic gases expected to be decomposition products of the glycine . The quantum efficiency for the decomposition of glycine by light at wavelengths from 2000 to 2400 angstroms was measured to be 1.46 +/- 1.0 x 10(-6) molecules/photon . Scaled to Mars, this represents an organic destruction rate of 2.24 +/- 1.2 x 10(-4) g of C m-2 yr-1 . We compare this degradation rate with the rate that organic compounds are brought to Mars as a result of meteoritic infall to show that organic compounds are destroyed on Mars at rates far exceeding the rate that they are deposited by meteorites . Thus the fact that no organic compounds were found on Mars by the Viking Lander Gas Chromatograph Mass Spectrometer experiment can be explained without invoking the presence of strong oxidants in the surface soils . The organic destruction rate may be considered as an upper bound for the globally averaged biomass production rate of extant organisms at the surface of Mars . This upper bound is comparable to the slow growing cryptoendolithic microbial communities found in dry Antarctica deserts . Finally, comparing these organic destruction rates to recently reported experiments on the stability of carbonate on the surface of Mars, we find that organic compounds may currently be more stable than calcite.

Geochim Cosmochim Acta, 1997 Dec, 61(24), 5351 - 61
Sulfur isotope fractionation during bacterial sulfate reduction in organic-rich sediments; Habicht KS et al.; Isotope fractionation during sulfate reduction by natural populations of sulfate-reducing bacteria was investigated in the cyanobacterial microbial mats of Solar Lake, Sinai and the sediments of Logten Lagoon sulfuretum, Denmark . Fractionation was measured at different sediment depths, sulfate concentrations, and incubation temperatures . Rates of sulfate reduction varied between 0.1 and 37 micromoles cm-3 d-1, with the highest rates among the highest ever reported from natural sediments . The depletion of 34S during dissimilatory sulfate reduction ranged from 16% to 42%, with the largest 34S-depletions associated with the lowest rates of sulfate reduction and the lowest 34S-depletions with the highest rates . However, at high sulfate reduction rates (>10 micromoles cm-3 d-1) the lowest fractionation was 20% independent of the rates . Overall, there was a similarity between the fractionation obtained by the natural populations of sulfate reducers and previous measurements from pure cultures . This was somewhat surprising given the extremely high rates of sulfate reduction in the experiments . Our results are explained if we conclude that the fractionation was mainly controlled by the specific rate of sulfate reduction (mass cell-1 time-1) and not by the absolute rate (mass volume-1 time-1) . Sedimentary sulfides (mainly FeS2) were on average 40% depleted in 34S compared to seawater sulfate . This amount of depletion was more than could be explained by the isotopic fractionations that we measured during bacterial sulfate reduction . Therefore, additional processes contributing to the fractionation of sulfur isotopes in the sediments are indicated . From both Solar Lake and Logten Lagoon we were able to enrich cultures of elemental sulfur-disproportionating bacteria . We suggest that isotope fractionation accompanying elemental sulfur disproportionation contributes to the 34S depletion of sedimentary sulfides at our study sites.

Enzyme Microb Technol, 1988 Oct, 10, 586 - 92
Reproducible analyses of microbial food for advanced life support systems; Petersen GR; The use of yeasts in Controlled Ecological Life Support Systems (CELSS) for microbial food regeneration in space required the accurate and reproducible analysis of intracellular carbohydrate and protein levels . The reproducible analysis of glycogen was a key element in estimating overall content of edibles in candidate yeast strains . Typical analytical methods for estimating glycogen in Saccharomyces were not found to be entirely applicable to other candidate strains . Rigorous cell lysis coupled with acid/base fractionation followed by specific enzymatic glycogen analyses were required to obtain accurate results in two strains of Candida . A profile of edible fractions of these strains was then determined . The suitability of yeasts as food sources in CELSS food production processes is discussed.

J Great Lakes Res, 1998, 24(1), 93 - 104
Biogeochemical cycling of manganese in Oneida Lake, New York: whole lake studies of manganese; Aguilar C et al.; Oneida Lake, New York is a eutrophic freshwater lake known for its abundant manganese nodules and a dynamic manganese cycle . Temporal and spatial distribution of soluble and particulate manganese in the water column of the lake were analyzed over a 3-year period and correlated with other variables such as oxygen, pH, and temperature . Only data from 1988 are shown . Manganese is removed from the water column in the spring via conversion to particulate form and deposited in the bottom sediments . This removal is due to biological factors, as the lake Eh/pH conditions alone can not account for the oxidation of the soluble manganese Mn(II) . During the summer months the manganese from microbial reduction moves from the sediments to the water column . In periods of stratification the soluble Mn(II) builds up to concentrations of 20 micromoles or more in the bottom waters . When mixing occurs, the soluble Mn(II) is rapidly removed via oxidation . This cycle occurs more than once during the summer, with each manganese atom probably being used several times for the oxidation of organic carbon . At the end of the fall, whole lake concentrations of manganese stabilize, and remain at about 1 micromole until the following summer, when the cycle begins again . Inputs and outflows from the lake indicate that the active Mn cycle is primarily internal, with a small accumulation each year into ferromanganese nodules located in the oxic zones of the lake.

Limnol Oceanogr, 1997 Nov, 42(7), 1561 - 9
Impact of light regimes on productivity patterns of benthic microbial mats in an antarctic lake: a modeling study; Moorhead DL et al.; Filamentous cyanobacteria often dominate benthic microbial communities of antarctic lakes and usually exhibit saturation of photosynthesis at light intensities approximately 100 microEinst m-2 s-1 . Incident light regimes are controlled by ice and snow accumulations overlaying water columns during much of the year . Thus, light availability to microbial mats is often below saturation intensity and is strongly influenced by modest changes in climatic factors . A model of net primary production for benthic mat communities of the subantarctic Sombre Lake, Signy Island, was developed (1) to evaluate depth-specific productivities of mat communities, (2) to test the relative importances of model parameters to mat production, and (3) to explore the potential impacts of climate change on mat production as manifested through changes in light regime . Simulated rates of net primary production corresponded to observations on a daily basis (approximately 1-4 micrograms C fixed mg-1 ash-free DW of mat d-1) but were an order of magnitude lower than estimates of net annual production based on field measurements (< or = 3 vs . 11-45 g C m-2 yr-1, respectively) . Close examination suggested that the simulated values were more plausible . A detailed sensitivity analysis of model behavior revealed that variations in the time of ice and snow melt in spring accounted for 40-60% of the total variation in model behavior, emphasizing the importance of climatic factors to net primary production of mat communities and the sensitivity of mat production to climate change.

Planet Space Sci, 1996 Nov, 44(11), 1435 - 40
Why exobiology on Mars?
Brack A.
Processing of organic molecules by liquid water was probably an essential requirement towards the emergence of terrestrial primitive life . According to Oparin's hypothesis, organic building blocks required for early life were produced from simple organic molecules formed in a primitive reducing atmosphere . Geochemists favour now a less reducing atmosphere dominated by carbon dioxide . In such an atmosphere, very few building blocks are formed . Import of extraterrestrial organic molecules may represent an alternative supply . Experimental support for such an alternative scenario is examined in comets, meteorites and micrometeorites . The early histories of Mars and Earth clearly show similarities . Liquid water was once stable on the surface of Mars attesting the presence of an atmosphere capable of decelerating C-rich micro-meteorites . Therefore, primitive life may have developed on Mars, as well . Liquid water disappeared from the surface of Mars very early, about 3.8 Ga ago . The Viking missions did not find, at the surface of the Martian soil, any organic molecules or clear-cut evidence for microbial activities such as photosynthesis, respiration or nutrition . The results can be explained referring to an active photochemistry of Martian soil driven by the high influx of solar UV . These experiments do not exclude the existence of organic molecules and fossils of micro-organisms which developed on early Mars until liquid water disappeared . Mars may store below its surface some well preserved clues of a still hypothetical primitive life.

Acta Astronaut, 1997 Jul, 41(1), 57 - 62
Immune organs and haemopoietic system under modelling of the mission factors; Sapin MR et al.; Literary and experimental data on the character of changes in immune organs and lymphoid tissue of respiratory system and digestive system in laboratory animals during the mission factors model area given . Inhibition of reproductive function in bone marrow, thymus and spleen under irradiation of gamma-rays and accelerated carbon ions, tensity of immune response in the lymphoid structures of larynx, trachea and bronchi under the influence of acetaldehyde vapors and decrease of lymphoid tissue square on histological series in spleen and small intestine with an increase of concentration of microbial bodies in the drinking water were estimated.

Acta Astronaut, 1997 Jan-Apr, 40(2-8), 195 - 201
New methods for microbial contamination monitoring: an experiment on board the MIR orbital station; Guarnieri V et al.; Experiment T2, carried out during the Euromir'95 mission, was an important step toward innovative methods for spacecraft microbial contamination monitoring . A new standard sampling technique permitted samples to be analysed by different means . On board, two analysis methods were tested in parallel: Bioluminescence and Miniculture . In turn, downloaded samples are being analysed by polymerase chain reaction (PCR), a powerful and promising method for the rapid detection, identification and quantification of pathogens and biofouling agents in closed manned habitats.

Phytopathology, 1997 Nov, 87(11), 1125 - 33
Seedborne fungal contamination: consequences in space-grown wheat; Bishop DL et al.; Plants grown in microgravity are subject to many environmental stresses that may promote microbial growth and result in disease symptoms . Wheat (cv . Super Dwarf) recovered from an 8-day mission aboard a NASA (National Aeronautics and Space Administration) space shuttle showed disease symptoms, including girdling of leaf sheaths and chlorosis and necrosis of leaf and root tissues . A Neotyphodium species was isolated from the seed and leaf sheaths of symptomatic wheat used in the spaceflight mission . Certain isozymes of a peroxidase unique to extracts from the microgravity-grown plants were observed in extracts from earth-grown Neotyphodium-infected plants but were not present in noninfected wheat . The endophytic fungus was eliminated from the wheat seed by prolonged heat treatment at 50 degrees C followed by washes with water at 50 degrees C . Plants from wheat seed infected with the Neotyphodium endophyte were symptomless when grown under greenhouse conditions, whereas symptoms appeared after only 4 days of growth in closed containers . Disease spread from an infected plant to noninfected plants in closed containers . Dispersion via spores was found on asymptomatic plants at distances of 7 to 18 cm from infected plants . The size and shape of the conidia, mycelia, and phialide-bearing structures and the ability to grow rapidly on carbohydrates, especially xylose, resembled the characteristics of N . chilense, which is pathogenic on orchard grass, Doctylis glomerati . The Neotyphodium wheat isolate caused disease symptoms on other cereals (wheat cv . Malcolm, orchard grass, barley, and maize) grown in closed containers.

Physiol Plant, 1995, 95, 533 - 40
On the use of antibiotics to reduce rhizoplane microbial populations in root physiology and ecology investigations; Smart DR et al.; No straightforward method exists for separating the proportion of ion exchange and respiration due to rhizoplane microbial organisms from that of root ion exchange and respiration . We examined several antibiotics that might be used for the temporary elimination of rhizoplane bacteria from hydroponically grown wheat roots (Triticum aestivum cv . Veery 10) . Each antibiotic was tested for herbicidal activity and plate counts were used to enumerate bacteria and evaluate antibiotic kinetics . Only lactam antibiotics (penicillins and cephalosporins) did not reduce wheat growth rates . Aminoglycosides, the pyrimidine trimethoprim, colistin and rifampicin reduced growth rates substantially . Antibiotics acted slowly, with maximum reductions in rhizoplane bacteria occurring after more than 48 h of exposure . Combinations of nonphytotoxic antibiotics reduced platable rhizoplane bacteria by as much as 98%; however, this was generally a reduction from about 10(9) to 10(6) colony forming units per gram of dry root mass, so that many viable bacteria remained on root surfaces . We present evidence which suggests that insufficient bacterial biomass exists on root surfaces of nonstressed plants grown under well-aerated conditions to quantitatively interfere with root nitrogen absorption measurements.

Geology, 1997 Sep, 25(9), 827 - 30
Evidence of ancient life at 207 m depth in a granitic aquifer; Pedersen K et al.; The results of electron-microscopy investigations of calcite precipitated in a water-conducting fracture in a ca . 1800 Ma granitic rock from 207 m below sea level at the island of Aspo on the southeastern (Baltic) coast of Sweden are compared with measurements of carbon, oxygen, and sulfur isotope composition of the calcite and embedded pyrite . Parts of the calcite had extremely low delta 13C values, indicative of biological activity, and contained bacteria-like microfossils occurring in colonies and as typical biofllms . X-ray microanalysis demonstrated these fossils to be enriched in carbon . Our results provide evidence for ancient life in deep granitic rock aquifers and suggest that the modern microbial life found there is intrinsic . Modeling historical and present geochemical processes in deep granitic aquifers should, therefore, preferably include biologically catalyzed reactions . The results also suggest that the search for life on other planets, e.g., Mars, should include subsurface material.

Life Support Biosph Sci, 1998, 5(1), 35 - 43
Next generation physico-chemical systems for water reclamation aboard spacecraft, lunar and planetary habitats; Atwater JE et al.; The extent to which bioregenerative processes will be incorporated into future life support systems is not known . Until biologically based processes reach a higher state of readiness, more advanced physico-chemical systems will be required that are capable of reliable operation for long periods with a minimal resupply penalty by minimizing the requirement for expendables . Water reclamation systems must perform three primary functions: 1) removal of suspended solids, 2) removal of dissolved contaminants, 3) and control of microbial growth . In this article, regenerable physico-chemical systems capable of performing these tasks are discussed . These systems may be appropriate for near-term deployments such as a space station retrofit, a lunar outpost, or a Mars transit vehicle.

Planta, 1997 Sep, 203(Suppl 1), S201 - 8
The Closed Equilibrated Biological Aquatic System: general concept and aspects of botanical research; Blum V et al.; The Closed Equilibrated Biological Aquatic System (CEBAS) consists of four subcomponents which form a closed (artificial) aquatic ecosystem initially designed to study the long-term influence of space conditions on several successive generations of aquatic organisms . Teleost fishes and water snails in the zoological component produce CO2 ammonium ions and waste compounds which can be utilized after ammonium is oxidised in a microbial component by the botanical component consisting of a rootless, aquatic higher plant species which eliminates ions, i.e . nitrate, and produces oxygen for animal respiration . An electronic component serves as a data-acquisition and regulation device for temperature and oxygen-dependent illumination of the plant chamber . A comprehensive interdisciplinary research programme, focused around the CEBAS, is especially well developed in the field of zoology . It covers a ground laboratory and preparations for two scheduled space flight projects, as well as aspects of combined animal-plant food production modules for human nutrition in bioregenerative space life-support systems and for terrestrial production sites . In the botanical research programme, morphological investigations on Ceratophyllum demersum L . performed with light and electron microscopy have demonstrated a gas lacuna system which, in addition to starch grains in the plastids, might regulate the buoyancy of the plant and/or serve as a 'gas skeleton' . Also, a remarkable symmetry in the arrangement of tissues was observed in stems and older leaves . The photosynthetic capacities of Ceratophyllum in the CEBAS-MINI MODULE proved to be more than sufficient for life support, and experiments on nitrate uptake into the plants showed their capacity to utilize ions from the water.

Adv Space Res, 1994 Nov, 14(11), 71 - 4
Biological life support for manned missions by ESA; Binot RA et al.; The anticipated evolution of life support technologies for ESA, considering both the complementary life support system requirements and the missions' characteristics, is presented . Based on these results, promising biological life support technologies for manned space missions have been selected by ESA either for their intrinsic ability and performance in effecting specific tasks for atmosphere-, water-, waste-management versus physico-chemical alternatives and/or for longer-term application to a more ecological concept (CES) focusing ultimately on food production . Actual status and plan for terrestrial and space testing of biological life support presented focusing on the "task specific" decontamination technology of the Biological Air Filter (BAF), and on food reprocessing technologies from biodegradable wastes with the MELISSA microbial ecosystem.

J Environ Sci Health A Environ Sci Eng Toxic Hazard Subst Control, 1996 Sep, A31(8), 1965 - 79
Numerical simulation of iodine speciation in relation to water disinfection aboard manned spacecraft I . Equilibria; Atwater JE et al.; Elemental iodine (I2) is currently used as the drinking water disinfectant aboard the Shuttle Orbiter and will also be incorporated into the water recovery and distribution system for the International Space Station Alpha . Controlled release of I2 is achieved using the Microbial Check Valve (MCV), a flow-through device containing an iodinated polymer which imparts a bacteriostatic residual concentration of approximately 2mg/L to the aqueous stream . During regeneration of MCV canisters, I2 concentrations of approximately 300 mg/L are used . Dissolved iodine undergoes a series of hydrolytic disproportionation and related reactions which result in the formation of an array of inorganic species including: I-, I3-, HOI, OI-, IO3-, HIO3, I2OH-, I2O(-2), and H2OI+ . Numerical estimation of the steady-state distribution of inorganic iodine containing species in pure water at 25 degrees C has been achieved by simultaneous solution of the multiple equilibrium expressions as a function of pH . The results are reported herein.

Can J Microbiol, 1985, 31, 493 - 8
Quantitative determination of microbial activity and community nutritional status in estuarine sediments: evidence for a disturbance artifact; Findlay RH et al.; In estuarine sediments with a high degree of vertical heterogeneity in reduced substrate and terminal electron acceptor concentrations, the method of exposure of the microbiota to labeled substrates can introduce a "disturbance artifact" into measures of metabolic activity . The detection of this artifact is based on quantitative measurement of the relative rates of incorporation of {14C}acetate into phospholipid fatty acids (PLFA) and endogenous storage lipid, poly-beta-hydroxyalkanoate (PHA) . Previous studies have shown that PLFA synthesis measures cellular growth and that PHA synthesis measures carbon accumulation (unbalanced growth) . The "disturbance artifact" of exposure to {14C}acetate was demonstrated by comparing injection of a core with the usual or pore-water replacement or slurry techniques . Only injection of labeled substrate allowed detection of preassay disturbance of the sediment with a garden rake . The raking increased PLFA synthesis with little effect to differences in concentration or distribution of {14C}acetate in the 10-min incubation . Bioturbation induced by sand dollar feeding in estuarine sediment could be detected in an increased PLFA/PHA ratio which was due to decreased PHA synthesis if the addition of labeled substrate was by the injection technique . Addition of labeled precursors to sediment by slurry or pore-water replacement induces greater disturbance artifacts than injection techniques.

Bioscience, 1993 Jun, 43(6), 390 - 3
Did surface temperatures constrain microbial evolution?
Schwartzman D, McMenamin M, Volk T.
NASA: The proposition that glaciation may not have occurred before the Cenozoic--albeit not yet a consensus position--nevertheless raises for reconsideration the surface temperature history of the earth . Glacial episodes, from the Huronian (2.3 billion years ago; BYA) through the late Paleozoic (320 to 250 million years ago; MYA) have been critical constraints on estimation of the upper bounds of temperature (Crowley 1983, Kasting and Toon 1989) . Once removed, few if any constraints on the upper temperature limit other than life remain . Walker (1982) recognized that life provides an upper limit to temperature in the Precambrian . We propose a more radical concept: the upper temperature limit for viable growth of a given microbial group corresponds to the actual surface temperature at the time of the group's first appearance . In particular, we propose here that two major evolutionary developments--the emergence of cyanobacteria and aerobic eukaryotes--can be used to determine surface temperature in the Precambrian, and that only subsequent cooling mediated by higher plants and then angiosperms permitted what may possibly be the earth's first glaciation in the late Cenozoic . NASA Edited

Icarus, 1992, 95, 300 - 8
On the possibility of chemosynthetic ecosystems in subsurface habitats on Mars; Boston PJ et al.; We have reexamined the question of extant microbial life on Mars in light of the most recent information about the planet and recently discovered nonphotosynthetic microbial ecosystems on Earth--deep sea hydrothermal vent communities and deep subsurface aquifer communities . On Mars, protected subsurface niches associated with hydrothermal activity could have continued to support life even after surface conditions became inhospitable . Geochemical evidence from the SNC meteorites and geomorphological evidence for recent volcanism suggest that such habitats could persist to the present time . There are also extensive geological features that attest to the ubiquitous nature of volcano-ground ice interactions on Mars . We suggest a possible deep subsurface microbial ecology similar to those discovered to depths of several kilometers below the surface of the Earth . We focus on anaerobic systems utilizing CO2 as the primary source of carbon . Liquid water could be provided by the heat of geothermal or volcanic activity melting permafrost or other subsurface water sources . Gases from volcanic activity deep in the planet could provide reducing power (as CH4, H2, or H2S) percolating up from below and enabling the development of a microbial community based upon chemolithoautotrophy . We suggest a methanogen (or acetogen) and sulfur-based microbial ecology as one possible basis for microbial primary production . Our hypothetical ecosystem is neither supported, nor excluded, by current observations of Mars . Tests for such a subsurface system involve locating active geothermal areas associated with ground ice or detecting trace quantities of reduced atmospheric gases that would leak from such a system.

Geochim Cosmochim Acta, 1989, 53, 2451 - 5
Origins of etioporphyrins in sediments: evidence from stable carbon isotopes; Boreham CJ et al.; In samples of the Julia Creek and Condor oil shales (Australia, Albian, and early Tertiary, respectively) etioporphyrin III is significantly depleted in 13C (4%) relative to porphyrins derived from chlorophylls . This isotopic difference suggests a large contribution from some independent source . The haem group found in cytochromes derived from microbial sources is the most likely candidate.

J Microbiol Methods, 1988, 8, 209 - 17
Analysis of lipophilic pigments from a phototrophic microbial mat community by high performance liquid chromatography; Palmisano AC et al.; As assay for lipophilic pigments in phototrophic microbial mat communities using reverse phase-high performance liquid chromatography was developed which allows the separation of 15 carotenoids and chloropigments in a single 30 min program . Lipophilic pigments in a laminated mat from a commercial salina near Laguna Guerrero Negro, Baja California Sur, Mexico reflected their source organisms . Myxoxanthophyll, echinenone, canthaxanthin, and zeaxanthin were derived from cyanobacteria; chlorophyll c, and fucoxanthin from diatoms; chlorophyll a from cyanobacteria and diatoms; bacteriochlorophylls a and c, bacteriophaeophytin a, and gamma-carotene from Chloroflexus spp.; and beta-carotene from a variety of phototrophs . Sensitivity of detection was 0.6-6.1 ng for carotenoids and 1.7-12 ng for most chloropigments . This assay represents a significant improvement over previous analyses of lipophilic pigments in microbial mats and promises to have a wider application to other types of phototrophic communities.

Science, 1987 Apr 3, 236, 66 - 8
Natural abundances of carbon isotopes in acetate from a coastal marine sediment; Blair NE et al.; Measurements of the natural abundances of carbon isotopes were made in acetate samples isolated from the anoxic marine sediment of Cape Lookout Bight, North Carolina . The typical value of the total acetate carbon isotope ratio (delta 13C) was -16.1 +/- 0.2 per mil . The methyl and carboxyl groups were determined to be -26.4 +/- 0.3 and -6.0 +/- 0.3 per mil, respectively, for one sample . The isotopic composition of the acetate is thought to have resulted from isotopic discriminations that occurred during the cycling of that molecule . Measurements of this type, which have not been made previously in the natural environment, may provide information about the dominant microbial pathways in anoxic sediments as well as the processes that influence the carbon isotopic composition of biogenic methane from many sources.

Adv Space Res, 1984, 4(10), 187 - 97
The microlesion concept in HZE particle dosimetry; Todd P et al.; High energy, high-Z (HZE) particles are present in high-altitude and high-inclination satellite orbits . Most of the HZE dose above LET = 200 keV/micrometer is due to Fe nuclei . Individual HZE particles can damage several cells adjacent to one another along the particle track in tissue . The outcome has been described as a "microlesion" by D . Grahn . The present study attempts to define conditions for microlesions in specific tissues, to seek biological evidence that microlesions are produced, and to evaluate the microlesion as a potentially useful unit of dose in assessing hazards to spaceworkers . Microlesions in individuals cells and hair follicles have been described . Microbial studies have provided some evidence for independent secondary electron action . Whether or not a few hundred microlesions would be damaging to the whole organism depends upon the nature of damage to critical tissues . For example, cancer may occur if microlesions kill several cells in a straight line and mutate other cells alongside the particle track . Fe particle irradiation of the mouse Harderian gland (Fry et al., this issue) produces tumors efficiently . Microlesions in the lens, cornea, and retina need to be considered . Further dialogue is required before a final decision can be made concerning the most appropriate way to assess the HZE hazard.

Orig Life Evol Biosph, 1985, 15, 347 - 52
The microbial community at Laguna Figueroa, Baja California Mexico: from miles to microns; Stolz JF; Laguna Figueroa is a lagoonal complex on the Pacific coast of the Baja California penisula 200 km south of the Mexican-United States border . The hypersaline lagoon is 16 km long and 2-3 km wide with a salt marsh and evaporite flat and is separated from the ocean by a barrier dune and beach . At the salt marsh-evaporite flat interface a stratified microbial community dominated by Microcoleus chthonoplastes is depositing laminated sediments . Similar stratiform deposits with associated microbial mat communities have been found in cherts of the Fig Tree Group, South Africa which are 3.4 GE in age . Heavy rains in the winters of 1978-1979 and 1979-1980 flooded the evaporite flat with 1-3 meters of meteoric water and buried the laminated sediment under 5-10 cm of siliciclastic and clay sediment . These flooding events had a dramatic effect on the composition of the mat community . The Microcoleus dominated community, with species of Chloroflexus sp . and an Ectothiorhodospira-like filamentous purple phototroph, disappeared leaving a community dominated by the purple phototrophs Chromatium sp . and Thiocapsa sp . Recolonization of the surface by species of the cyanobacteria Oscillatoria sp . and Spirulina sp . preceded the return of the Microcoleus community . Field conditions were monitored by ground based observations and supplemented with LandSat and Skylab imagery . The microbial community was studied with light microscopy and transmission electron microscopy . The change in dominating microbial species was correlated with the episodes of flooding.

Phycologia, 1984, 23(4), 443 - 54
Hemichloris antarctica, gen . et sp . nov . (Chlorococcales, Chlorophyta), a cryptoendolithic alga from Antarctica; Tschermak-Woess E et al.; Hemichloris antarctica gen . et sp . nov . (Oocystaceae, Chlorococcales) is characterized by a single, articulated, pyrenoid-less, thick saucer-shaped chloroplast, which generally fills less than half of the cell periphery . Multiplication is only by autospores . The species is psychrophilic and is damaged at temperatures above 20 degree C . Hemichloris antarctica is a member of the cryptoendolithic microbial community living in porous sandstone rocks of the Antarctica cold desert . It inhabits the zone below that of cryptoendolithic lichens and survives at extremely low light intensities . In the natural habitat, morphology is somewhat different from that in culture, as chloroplasts are smaller and without articulation, and the cells develop a gelatinous sheath.

Syst Appl Microbiol, 1995, 18, 274 - 8
Diverse Thermus species inhabit a single hot spring microbial mat; Nold SC et al.; Through an effort to characterize aerobic chemoorganotrophic bacteria in the Octopus Spring cyano-bacterial mat community, we cultivated four Thermus isolates with unique 16S rRNA sequences . Isolates clustered within existing Thermus clades, including those containing Thermus ruber, Thermus aquaticus, and a subgroup closely related to T . aquaticus . One Octopus Spring isolate is nearly identical (99.9% similar) to isolates from Iceland, and two others are closely related to a T . ruber isolated from Russia . Octopus Spring isolates similar to T . aquaticus and T . ruber exhibited optimal growth rates at high (65-70 degrees C) and low (50 degrees C) temperatures, respectively, with the most abundant species best adapted to the temperature of the habitat (50-55 degrees C) . Our results display a diversity of Thermus genotypes defined by 16S rRNA within one hot spring microbial community . We suggest that specialization to temperature and perhaps other local environmental features controls the abundance of Thermus populations.

Arch Microbiol, 1993, 160, 461 - 70
Spirosymplokos deltaeiberi nov . gen., nov . sp.: variable-diameter composite spirochete from microbial mats; Guerrero R et al.; Large (up to 100 micrometers long), loosely coiled, free-living spirochetes with variable diameters (from 0.4 to 3 micrometers in the same cell) were seen at least 40 times between August 1990 and January 1993 . These spirochetes were observed in mud water and enrichment media from highly specific habitats in intertidal evaporite flats at three disjunct localities, one in Spain and two in Mexico . All three are sites of commercial saltworks . Associated with Microcoleus chthonoplastes the large spirochetes from Spain display phototaxis and a composite organization . Shorter and smaller-diameter spirochetes are seen inside both healthy and spent periplasm of larger ones . Small spirochetes attached to large ones have been observed live . From two to twelve spirochete protoplasmic cylinders were seen inside a single common outer membrane . A distinctive granulated cytoplasm in which the granules are of similar diameter (20-32 nanometers) to that of the flagella (26 nanometers) was present . Granule diameters were measured in thin section and in negatively-stained whole-mount preparations . Based on their ultrastructure, large size, variable diameter, number of flagella (3 to 6), and phototactic behavior these unique spirochetes are formally named Spirosymplokos deltaeiberi . Under anoxic (or low oxygen) conditions they formed blooms in mixed culture in media selective for spirochetes . Cellobiose was the major carbon source in 80% seawater, the antibiotic rifampicin was added, mat from the original field site was present and tubes were incubated in the light at from 18-31 degrees C . Within 1-2 weeks populations of the large spirochete developed at 25 degrees C but they could not be transferred to fresh medium.

Antarct J US, 1993, 28(5), 252 - 4
Biologically active substances produced by antarctic cryptoendolithic fungi; Ocampo-Friedmann R et al.; NASA: Researchers report results of laboratory studies of over 200 microbial strains of fungi, algae, cyanobacteria, and heterotrophic bacteria collected in the Ross Desert region of Antarctica . All of the 35 fungal strains produced substances that inhibited the growth of cyanobacteria and algae . The inhibitory effect of the biologically active substance was evident in crushed cell extract but less in spent broth .

Org Geochem, 1994, 21(10-11), 1037 - 49
The effect of aromatization on the isotopic compositions of hydrocarbons during early diagenesis; Freeman KH et al.; Polycyclic aromatic hydrocarbons with varying degrees of aromatization were isolated from the Eocene Messel Shale (Rheingraben, Germany) . The high abundances of these compounds and their structural resemblances to cyclic triterpenoid lipids are consistent with derivation from microbial rather than thermal processes . Compounds structurally related to oleanane contain from five to nine double bonds; those within a series of aromatized hopanoids contain from three to nine . All are products of diagenetic reactions that remove hydrogen or methyl groups, and, in several cases, break carbon-carbon bonds to open rings . Aromatized products are on average depleted in 13C relative to possible precursors by l.2% (range: l.5% enrichment to 4% depletion, n = 9) . The dependence of 13C content on the number of double bonds is not, however, statistically significant and it must be concluded that there is no strong evidence for isotopic fractionation accompanying diagenetic aromatization . Isotopic differences between series (structures related to ursane, des-A-ursane, des-A-lupane, des-A-arborane, and possibly, des-A-gammacerane are present) are much greater, indicating that 13C contents are controlled primarily by source effects . Fractionations due to chromatographic isotope effects during HPLC ranged from 0.1 to 2.8%.

Limnol Oceanogr, 1993, 38(6), 1150 - 61
Microscale characterization of dissolved organic matter production and uptake in marine microbial mat communities; Paerl HW et al.; Intertidal marine microbial mats exhibited biologically mediated uptake of low molecular weight dissolved organic matter (DOM), including D-glucose, acetate, and an L-amino acid mixture at trace concentrations . Uptake of all compounds occurred in darkness, but was frequently enhanced under natural illumination . The photosystem 2 inhibitor, 3-(3,4-dichlorophenyl)-1,1-dimethyl urea (DCMU) generally failed to inhibit light-stimulated DOM uptake . Occasionally, light plus DCMU-amended treatments led to uptake rates higher than light-incubated samples, possibly due to phototrophic bacteria present in subsurface anoxic layers . Uptake was similar with either 3H- or 14C-labeled substrates, indicating that recycling of labeled CO2 via photosynthetic fixation was not interfering with measurements of light-stimulated DOM uptake . Microautoradiographs showed a variety of pigmented and nonpigmented bacteria and, to a lesser extent, cyanobacteria and eucaryotic microalgae involved in light-mediated DOM uptake . Light-stimulated DOM uptake was often observed in bacteria associated with sheaths and mucilage surrounding filamentous cyanobacteria, revealing a close association of organisms taking up DOM with photoautotrophic members of the mat community . The capacity for dark- and light-mediated heterotrophy, coupled to efficient retention of fixed carbon in the mat community, may help optimize net production and accretion of mats, even in oligotrophic waters.

Adv Space Res, 1995 Mar, 15(3), 223 - 8
A "cryptic" microbial mat: a new model ecosystem for extant life on Mars; Rothschild LJ; If life were present on Mars to day, it would face potentially lethal environmental conditions such as a lack of water, frigid temperatures, ultraviolet radiation, and soil oxidants . In addition, the Viking missions did not detect near-surface organic carbon available for assimilation . Autotrophic organisms that lived under a protective layer of sand or gravel would be able to circumvent the ultraviolet radiation and lack of fixed carbon . Two terrestrial photosynthetic near-surface microbial communities have been identified, one in the inter- and supertidal of Laguna Ojo de Liebre (Baja California Sur, Mexico) and one in the acidic gravel near several small geysers in Yellowstone National Park (Wyoming, U.S.A.) . Both communities have been studied with respect to their ability to fix carbon under different conditions, including elevated levels of inorganic carbon . Although these sand communities have not been exposed to the entire suite of Martian environmental conditions simultaneously, such communities can provide a useful model ecosystem for a potential extant Martian biota.

Adv Space Res, 1995 Mar, 15(3), 215 - 21
Biogeochemical evidence of microbial activity on Mars; Ivanov MV et al.; We suggest a new interpretation of the data on so-called SNC meteorites and delta 13C values of the calcium carbonate minerals and organic matter discovered in them . The delta 13C value of calcite (up to 15 ppt) is accounted for by the microbial reaction CO2 + H2 ---> CH4 + H2O . Methane-forming bacteria also synthesize organic carbon (in the form of biomass) from CO2, and this process is accompanied by 12C fractionation . Therefore, the organic carbon of SNC meteorites is enriched with 12C (delta 13C as low as -35 ppt) . The environmental conditions under which the calcite of SNC meteorites was formed were favorable for the activity of methanogens.

Life Support Biosph Sci, 1996, 3(1-2), 35 - 41
Nitrogen dynamics in plant growth systems; Bloom AJ; The predominant nitrogen source for the plants in closed environmental systems is the mineral nitrogen (i.e., nitrate and/or ammonium) in the nutrient medium . The following focuses on the processes through which plants obtain nitrate and ammonium from the rhizosphere and on the influences that each form has upon plant performance . Most plant species can sustain full growth at nitrate or ammonium concentrations that are over two orders of magnitude lower than those provided in most plant growth systems . Under the high concentrations (mM) normally used, root nitrogen absorption is downregulated: a) both the affinity and capacity of the transport systems for ammonium or nitrate are diminished, b) efflux of either ion becomes a significant percentage of influx, and c) root growth is inhibited . High concentrations also promote accumulation of ammonium or borate in plant tissues to potentially deleterious levels and foster microbial outbreaks . Several lines of evidence argue that roots in natural soils are normally exposed to lower concentrations (micromoles) of nitrate or ammonium: models of root nutrient absorption indicate that roots deplete rhizosphere nitrate and ammonium to such levels; the high-affinity transport systems for nitrate and ammonium have optimal control in this range; and root growth and development is maximized under such conditions . The high-affinity transport systems are distinct for nitrate and ammonium . In general, the affinity of the nitrate system for nitrate is less than the ammonium system for ammonium . Nitrate absorption is induced by the presence of ammonium or nitrate . Roots most rapidly absorb nitrate in the zone where root hairs emerge and ammonium in the zone of division near the apex . Nitrate absorption tends to alkalinize the rhizosphere, whereas ammonium absorption acidifies the rhizosphere . The energy requirements for absorption and assimilation of nitrate are several fold higher than those of ammonium . Root growth and elongation are more extensive when ammonium is provided as the sole nitrogen source, perhaps as a consequence of the lower energy requirements or the increased rhizosphere acidity.

Adv Microb Ecol, 1995, 14, 251 - 74
The biogeochemistry of hypersaline microbial mats; Des Marais DJ; NASA: This chapter cites and summarizes a set of published studies that, as a set, provide a broad overview of the ecology of a single mat ecosystem . NASA Edited

Biol Bull, 1989 Aug, 177, 110 - 29
Ecology and life history of an amoebomastigote, Paratetramitus jugosus, from a microbial mat: new evidence for multiple fission; Enzien M et al.; Five microbial habitats (gypsum crust, gypsum photosynthetic community, Microcoleus mat, Thiocapsa scum, and black mud) were sampled for the presence of the euryhaline, rapidly growing amoebomastigote, Paratetramitus jugosus . Field investigations of microbial mats from Baja California Norte, Mexico, and Salina Bido near Matanzas, Cuba, reveal that P . jugosus is most frequently found in the Thiocapsa layer of microbial mats . Various stages of the life history were studied using phase-contrast, differential-interference, and transmission electron microscopy . Mastigote stages were induced and studied by electron microscopy; mastigotes that actively feed on bacteria bear two or more undulipodia . A three-dimensional drawing of the kinetid ("basal apparatus") based on electron micrographs is presented . Although promitoses were occasionally observed, it is unlikely that they can account for the rapid growth of P . jugosus populations on culture media . Dense, refractile, spherical, and irregular-shaped bodies were seen at all times in all cultures along with small mononucleate (approximately 2-7 micrometers diameter) amoebae . Cytochemical studies employing two different fluorescent stains for DNA (DAPI, mithramycin) verified the presence of DNA in these small bodies . Chromatin-like material seen in electron micrographs within the cytoplasm and blebbing off nuclei were interpreted to the chromatin bodies . Our interpretation, consistent with the data but not proven, is that propagation by multiple fission of released chromatin bodies that become small amoebae may occur in Paratetramitus jugosus . These observations are consistent with descriptions of amoeba propagules in the early literature (Hogue, 1914).

Geomicrobiol J, 1989, 7, 137 - 53
Distribution of inorganic species in two Antarctic cryptoendolithic microbial communities; Johnston CG et al.; Chemical differences were noted between two Antarctic cryptoendolithic (hidden within rock) microenvironments colonized by different microbial communities . Microenvironments dominated by cyanobacteria (BPC) had a higher pH (pH 7-8) than those dominated by lichen (LTL) (pH 4.5-5.5) . In order to understand the interactions between the microbiota and the inorganic environment, the inorganic environment was characterized . Water-soluble, carbonate-bound, metal-oxide, organically bound, and residual inorganic species were sequentially extracted from rock samples by chemical means . Each fraction was then quantified using inductively coupled plasma atomic emission spectrometry . BPC contained much more water-soluble and carbonate-bound Ca and Mg than LTL . Metal-oxide species of Al, Fe, and Mn were more abundant in LTL than BPC . Metal oxides appeared to be mobilized (in the order Mn > Fe > Al) from the LTL lichen zone but remained immobile in BPC sandstone . The distribution of K and P bound to metal oxide reflected the distribution of iron oxide in LTL, an indication of the importance of iron in controlling the availability of nutrients in this ecosystem . Metal oxides in turn were likely controlled or influenced by organic matter associated with the lichen community . Despite overall depletion of Fe, Al, and K in the lichen zone, SEM X-ray analysis showed that they were enriched in fungal hyphae . Water-soluble P was present despite the presence of metal oxides, which sequester phosphate . This has biological relevance since P is an essential nutrient.

Philos Trans R Soc Lond A, 1988, 325, 601 - 10
Planetary environments and the conditions of life; Chang S; Life arose on Earth within a billion years (1 Ga) after planetary accretion and core formation . The geological record, which begins 3.8 Ga BP, indicates environmental conditions much like today's, except for the absence of oxygen . By 3.5 Ga BP microbial ecosystems were already colonizing shallow marine hydrothermal environments along shorelines of volcanic islands . Although similar environments could have existed more than 3.8 Ga BP, they may not have been the spawning grounds of life . Geophysical models of the first 600 Ma of Earth history following accretion and core formation point to a period of great environmental disequilibrium . In such an environment the passage of energy from Earth's interior and from the Sun through gas-liquid-solid domains and their boundaries with each other generated a dynamically interacting, complex hierarchy of self-organized structures, ranging from bubbles at the sea-air interface to tectonic plates . Nested within this hierarchy were the precursors of living systems . The ability of a planet to produce such a hierarchy is speculated to be a prerequisite for the origin and sustenance of life . Application of this criterion to Mars, which apparently experienced no plate tectonism, argues against the origin of martian life . Because only further geological and biogeochemical exploration of the planet can place these qualitative speculations on firm ground, the search for evidence of extinct life on Mars continues to be of highest scientific priority.

Polar Biol, 1987, 7, 273 - 87
The cryptoendolithic microbial environment in the Ross Desert of Antarctica: satellite-transmitted continuous nanoclimate data, 1984 to 1986; Friedmann EI et al.; A satellite mediated station for monitoring nanoclimate (climate in the millimeter range) data, suitable for use in polar regions is described . The station, located in the Ross desert of Antarctica, has been in operation for more than 3 years, measuring rock temperatures, air temperature, light, snow, wind, and moisture . The data indicate that biological activity in the cryptoendolithic microbial ecosystem is limited to the period from mid November to mid February . The total number of hours of biological activity, based on assumptions of the minimum light, temperature and moisture requirements of the community, is less than 1000 h/year . The time above 0 degrees C, representing more nearly optimal conditions, is between 50 and 550 h/year, depending on the orientation of the surface.

Bioscience, 1985 Sep, 35(8), 499 - 503
Cryoconite holes on glaciers; Wharton RA Jr et al.; Cryoconite holes are water-filled depressions on the surface of glaciers . They contain microbial communities and may contribute to glacial wastage and biological colonization of ice-free areas.

Limnol Oceanogr, 1990, 35(6), 1343 - 55
The diffusive boundary layer of sediments: oxygen microgradients over a microbial mat; Jorgensen BB et al.; Oxygen microelectrodes were used to analyze the distribution of the diffusive boundary layer (DBL) at the sediment-water interface in relation to surface topography and flow velocity . The sediment, collected from saline ponds, was covered by a microbial mat that had high oxygen consumption rate and well-defined surface structure . Diffusion through the DBL constituted an important rate limitation to the oxygen uptake of the sediment . The mean effective DBL thickness decreased from 0.59 to 0.16 mm as the flow velocity of the overlying water was increased from 0.3 to 7.7 cm s-1 (measured 1 cm above the mat) . The oxygen uptake rate concurrently increased from 3.9 to 9.4 nmol cm-2 min-1 . The effects of surface roughness and topography on the thickness and distribution of the DBL were studied by three-dimensional mapping of the sediment-water interface and the upper DBL boundary at 0.1-mm spatial resolution . The DBL boundary followed mat structures that had characteristic dimensions > 1/2 DBL thickness but the DBL had a dampened relief relative to the mat . The effective surface area of the sediment-water interface and of the upper DBL boundary were 31 and 14% larger, respectively, than a flat plane . Surface topography thereby increased the oxygen flux across the sediment-water interface by 49% relative to a one-dimensional diffusion flux calculated from the vertical oxygen microgradients.

Arch Microbiol, 1990, 153, 422 - 7
Mobilifilum chasei: morphology and ecology of a spirochete from an intertidal stratified microbial mat community; Margulis L et al.; Spirochetes were found in the lower anoxiphototrophic layer of a stratified microbial mat (North Pond, Laguna Figueroa, Baja California, Mexico) . Ultra-structural analysis of thin sections of field samples revealed spirochetes approximately 0.25 micrometer in diameter with 10 or more periplasmic flagella, leading to the interpretation that these spirochetes bear 10 flagellar insertions on each end . Morphometric study showed these free-living spirochetes greatly resemble certain symbiotic ones, i.e., Borrelia and certain termite spirochetes, the transverse sections of which are presented here . The ultrastructure of this spirochete also resembles Hollandina and Diplocalyx (spirochetes symbiotic in arthropods) more than it does Spirochaeta, the well known genus of mud-dwelling spirochetes . The new spirochete was detected in mat material collected both in 1985 and in 1987 . Unique morphology (i.e., conspicuous outer coat of inner membrane, large number of periplasmic flagella) and ecology prompt us to name a new free-living spirochete.

Am Zool, 1990, 30, 861 - 75
Kingdom Animalia: the zoological malaise from a microbial perspective; Margulis L; Pain and cognitive dissonance abounds amongst biologists: the plant-animal, botany-zoology wound has nearly healed and the new gash--revealed by department and budget reorganizations--is "molecular" vs . "organismic" biology . Here I contend that resolution of these tensions within zoology requires that an autopoietic-gaian view replace a mechanical-neodarwinian perspective; in the interest of brevity and since many points have been discussed elsewhere, rather than develop detailed arguments I must make staccato statements and refer to a burgeoning literature . The first central concept is that animals, all organisms developing from blastular embryos, evolved from single protist cells that were unable to reproduce their undulipodia . The second points to the usefulness of recognizing the analogy between cyclically established symbioses and meiotic sexuality.

Mar Chem, 1991, 33, 335 - 51
Method for determining stable isotope ratios of dissolved organic carbon in interstitial and other natural marine waters; Bauer JE et al.; A procedure is described for the analysis of the stable carbon isotopic composition of dissolved organic carbon (DOC) in natural waters from marine and higher-salinity environments . Rapid (less than 5 min) and complete oxidation of DOC is achieved using a modification of previous photochemical oxidation techniques . The CO2 evolved from DOC oxidation can be collected in less than 10 min for isotopic analysis . The procedure is at present suitable for oxidation and collection of 1-5 micromoles of carbon and has an associated blank of 0.1-0.2 micromole of carbon . Complete photochemical oxidation of DOC standards was demonstrated by quantitative recovery of CO2 as measured manometrically . Isotopic analyses of standards by photochemical and high-temperature sealed-tube combustion methods agreed to within 0.3% . Photochemical oxidation of DOC in a representative sediment pore-water sample was also quantitative, as shown by the excellent agreement between the photochemical and sealed-tube methods . The delta 13C values obtained for pore-water DOC using the two methods of oxidation were identical, suggesting that the modified photochemical method is adequate for the isotopically non-fractionated oxidation of pore-water DOC . The procedure was evaluated through an analysis of DOC in pond and pore waters from a hypersaline microbial mat environment . Concentrations of DOC in the water column over the mat displayed a diel pattern, but the isotopic composition of this DOC remained relatively constant (average delta 13C = -12.4%) . Pore-water DOC exhibited a distinct concentration maximum in the mat surface layer, and delta 13C of pore-water DOC was nearly 8% lighter at 1.5-2.0-cm depth than in the mat surface layer (0-0.5-cm depth) . These results demonstrate the effectiveness of the method in elucidating differences in DOC concentration and delta 13C over biogeochemically relevant spatial and temporal scales . Carbon isotopic analysis of DOC in natural waters, especially pore waters, should be a useful probe of biogeochemical processes in recent environments.

Sedimentology, 1991, 38, 363 - 79
Lake Hoare, Antarctica: sedimentation through a thick perennial ice cover; Squyres SW et al.; Lake Hoare in the Dry Valleys of Antarctica is covered with a perennial ice cover more than 3 m thick, yet there is a complex record of sedimentation and of growth of microbial mats on the lake bottom . Rough topography on the ice covering the lake surface traps sand that is transported by the wind . In late summer, vertical conduits form by melting and fracturing, making the ice permeable to both liquid water and gases . Cross-sections of the ice cover show that sand is able to penetrate into and apparently through it by descending through these conduits . This is the primary sedimentation mechanism in the lake . Sediment traps retrieved from the lake bottom indicate that rates of deposition can vary by large amounts over lateral scales as small as 1 m . This conclusion is supported by cores taken in a 3 x 3 grid with a spacing of 1.5 m . Despite the close spacing of the cores, the poor stratigraphic correlation that is observed indicates substantial lateral variability in sedimentation rate . Apparently, sand descends into the lake from discrete, highly localized sources in the ice that may in some cases deposit a large amount of sand into the lake in a very short time . In some locations on the lake bottom, distinctive sand mounds have been formed by this process . They are primary sedimentary structures and appear unique to the perennially ice-covered lacustrine environment . In some locations they are tens of centimetres high and gently rounded with stable slopes; in others they reach approximately 1 m in height and have a conical shape with slopes at angle of repose . A simple formation model suggests that these differences can be explained by local variations in water depth and sedimentation rate . Rapid colonization of fresh sand surfaces by microbial mats composed of cyanobacteria, eukaryotic algae, and heterotrophic bacteria produces a complex intercalation of organic and sandy layers that are a distinctive form of modern stromatolites.

Precambrian Res, 1991, 53, 165 - 97
Coastal lithofacies and biofacies associated with syndepositional dolomitization and silicification (Draken Formation, Upper Riphean, Svalbard); Fairchild IJ et al.; The Draken Formation (120-250 m) of northeast Spitsbergen (Svalbard) forms part of a thick Upper Proterozoic carbonate platform succession . It consists predominantly of intraformational dolomitic conglomerates, with excellent textural preservation . Six main lithofacies were recognized in the field: quartz sandstones, stromatolitic mats, conglomerates with silicified intraclasts, dolostone conglomerates with desiccated mudrocks, oolitic/pisolitic grainstones and fenestral dolostones . A series of five main gradational biofacies were recognized from silicified (and rare calcified) microfossils . Biofacies 1 represents low-energy subtidal benthos (erect filaments) and plankton (acritarchs and vase-shaped microfossils) whereas biofacies 2 to 5 are microbial mat assemblages (with filamentous mat-builders, and associated dwellers and washed-in plankton) ranging from basal intertidal to high intertidal/supratidal . Colour values (a measure of the lightness of the colour shade) of sawn rock samples were quantified using a Munsell chart, and exhibit a pronounced variation (means of major groups varying from 4.0 to 5.95) across the spectrum of subtidal to supratidal sediments as inferred from other criteria . The lightening in progressively more exposed sediments is related to lowering of organic carbon contents, probably mainly by oxidation . Six types of early cement have been recognized . Calcite microspar (type 1) is common as a subtidal cement in many Proterozoic formations, whereas types 2 (subtidal isopachous fringes), 3 (subtidal hardground dolomicrite) and 4 (intertidal meniscus dolomicrite) are very similar to Phanerozoic examples except for their dolomitic mineralogy . Types 5 and 6 are complex and variable dolomite growths associated with expansion and replacive phenomena . They characterize the fenestral lithofacies and compare with modern supratidal cements . Consideration of diagenetic fabrics and truncation textures of intraclasts indicates that leaching, dolomitization, silicification were all significant syndepositional processes altering the original metastable carbonates . The data set provides evidence for a spectrum of peritidal environments including ooid shoals, protected subtidal, tidal sandflats and protected carbonate mudflats . Different sections show a preponderance of particular facies . The coastal lithofacies continuum was completely dolomitized, unlike offshore to ooid shoal facies of adjacent formations . Dolomitization thus bears a relationship to depositional bathymetry . Although hydrodynamics clearly have a role, the potential importance of whiting precipitation in raising Mg/Ca in marginal marine environments is also stressed.

Planet Space Sci, 1995 Jan-Feb, 43(1-2), 189 - 217
Exobiology, the study of the origin, evolution and distribution of life within the context of cosmic evolution: a review; Horneck G; The primary goal of exobiological research is to reach a better understanding of the processes leading to the origin, evolution and distribution of life on Earth or elsewhere in the universe . In this endeavour, scientists from a wide variety of disciplines are involved, such as astronomy, planetary research, organic chemistry, palaeontology and the various subdisciplines of biology including microbial ecology and molecular biology . Space technology plays an important part by offering the opportunity for exploring our solar system, for collecting extraterrestrial samples, and for utilizing the peculiar environment of space as a tool . Exobiological activities include comparison of the overall pattern of chemical evolution of potential precursors of life, in the interstellar medium, and on the planets and small bodies of our solar system; tracing the history of life on Earth back to its roots; deciphering the environments of the planets in our solar system and of their satellites, throughout their history, with regard to their habitability; searching for other planetary systems in our Galaxy and for signals of extraterrestrial civilizations; testing the impact of space environment on survivability of resistant life forms . This evolutionary approach towards understanding the phenomenon of life in the context of cosmic evolution may eventually contribute to a better understanding of the processes regulating the interactions of life with its environment on Earth.

J Paleontol, 1989, 63(2), 129 - 45
Paleoenvironmental distribution of microfossils and stromatolites in the Upper Proterozoic Backlundtoppen Formation, Spitsbergen; Knoll AH et al.; The Upper Proterozoic (ca . 700-800 Ma old) Backlundtoppen Formation, northeastern Spitsbergen, preserves an abundant and varied record of ancient microbial life . Five distinctive microfossil assemblages occur in five equally distinct sedimentary settings; differences among the assemblages appear to reflect original ecological heterogeneity, although taphonomic circumstance may contribute to some distinctions . Microfossil assemblages occur in: oncolites, oolites, and pisolites; stratiform stromatolites and associated intraclastic rudites; partially silicified micrites; and siltites interbedded with quartz arenites . Individual assemblages contain one to eight differentiable taxa; a minimum of 17 distinct populations is present in the formation as a whole . Additional microbial community diversity an be inferred from the presence of domal, columnar, pseudocolumnar, and coniform stromatolites, none of which contains microfossils . On the basis of macrostructure, four stromatolite types appear to be present, but only three distinct mat-building communities can be inferred from microstructural features . Eohyella elongata n . sp., a euendolithic cyanobacterium found in silicified pisolites, is described as new.

Microb Ecol, 1988, 16, 271 - 89
The cryptoendolithic microbial environment in the Ross Desert of Antarctica: light in the photosynthetically active region; Nienow JA et al.; The vertical zonation of the Antarctic cryptoendolithic community appears to form in response to the light regime in the habitat . However, because of the structure of the habitat, the light regime is difficult to study directly . Therefore, a mathematical model of the light regime was constructed, which was used to estimate the total photon flux in different zones of the community . Maximum fluxes range from about 150 micrometers photons m-2 s-1 at the upper boundary of the community to about 0.1 micrometer photons m-2 s-1 . Estimates of the annual productivity in the community indicate that the lowest zone of the community is light limited, with the maximal annual carbon uptake equivalent to less than the carbon content of one algal (Hemichloris) cell.

Microb Ecol, 1988, 16, 253 - 70
The cryptoendolithic microbial environment in the Ross Desert of Antarctica: mathematical models of the thermal regime; Nienow JA et al.; Microbial activity in the Antarctic cryptoendolithic habitat is regulated primarily by temperature . Previous field studies have provided some information on the thermal regime in this habitat, but this type of information is limited by the remoteness of the site and the harsh climatic conditions . Therefore, a mathematical model of the endolithic thermal regime was constructed to augment the field data . This model enabled the parameters affecting the horizontal and altitudinal distribution of the community to be examined . The model predicts that colonization should be possible on surfaces with zenith angle less than 15 degrees . At greater zenith angles, colonization should be restricted to surfaces with azimuth angles less than 135 degrees or greater than 225 degrees . The upper elevational limit of the community should be less than 2,500 m . The thermal regime probably does not influence the zonation of the community within a rock.

Antarct J US, 1988, 21(5), 225 - 6
Does iron inhibit cryptoendolithic microbial communities?
Johnston CG, Vestal JR.
Photosynthetic activity of three cryptoendolithic microbial communities was studied under controlled conditions in the laboratory . In two of these communities, the dominant organisms were lichens, collected from Linnaeus Terrace and from Battleship Promontory . The third community, dominated by cyanobacteria, was collected from Battleship Promontory . Both sites are in the ice-free valleys of southern Victoria Land . Previous efforts have shown how physical conditions can influence metabolic activity in endolithic communities (Kappen and Friedmann 1983; Kappen, Friedmann, and Garty 1981; Vestal, Federle, and Friedmann 1984) . Biological activity can also be strongly influenced by the chemical environment . Inorganic nutrients such as nitrate, ammonia, and phosphate are often limiting factors, so their effects on photosynthetic carbon-14 bicarbonate incorporation were investigated . Iron and manganese are two metals present in Linnaeus Terrace and Battleship Promontory sandstones, and their effects on photosynthesis were also studied . The results may add to our understanding of biogeochemical interactions within this unique microbial community.

Antarct J US, 1986, 21(5), 222 - 4
Biologically relevant physical measurements in the ice-free valleys of southern Victoria Land: soil temperature profiles and ultraviolet radiation; Nienow JA et al.; As part of the ongoing comprehensive study of the cryptoendolithic microbial community in the ice-free valleys of southern Victoria Land, thermal properties of the soil and the ultraviolet radiation regime were measured . Although soil temperature profiles have been measured in the ice-free valleys (e.g., Cameron et al . 1970; Cameron 1972), these are the first such data from higher elevations . This is apparently the first time the ultraviolet radiation regime has been measured in the Antarctic.

Life Support Biosph Sci, 1995 Fall, 2(2), 103 - 6
Life Support and Biospherics--a handbook; Eckart P; The new book Life Support and Biospherics--Fundamentals, Technologies, Applications is intended to be the "Introduction to Life Support Systems" that has been lacking so far . It contains information on any aspect of life support systems development and design . The structure of the books is such that it, step by step, answers the basic questions concerning terrestrial and space life support systems of any scale--from small microbial systems to the Earth's biosphere . This article gives an overview of the contents of Life Support and Biospherics.

Science, 1991 Mar 22, 251, 1471 - 3
Aerobic sulfate reduction in microbial mats; Canfield DE et al.; Measurements of bacterial sulfate reduction and dissolved oxygen (O2) in hypersaline bacterial mats from Baja California, Mexico, revealed that sulfate reduction occurred consistently within the well-oxygenated photosynthetic zone of the mats . This evidence that dissimilatory sulfate reduction can occur in the presence of O2 challenges the conventional view that sulfate reduction is a strictly anaerobic process . At constant temperature, the rates of sulfate reduction in oxygenated mats during daytime were similar to rates in anoxic mats at night: thus, during a 24-hour cycle, variations in light and O2 have little effect on rates of sulfate reduction in these mats.

Adv Space Res, 1992, 12(4), 231 - 8
History of water on Mars: a biological perspective; McKay CP et al.; We divide the history of water on the Martian surface into four epochs based upon the atmospheric temperature and pressure . In Epoch 1, during which a primordial CO2 atmosphere was actively maintained by impact and volcanic recycling, we presume the mean annual temperature to have been above freezing, the pressure to have exceeded one atmosphere, and liquid water to have been widespread . Under such conditions, similar to early Earth, life could have arisen and become abundant . After this initial period of recycling, atmospheric CO2 was irreversibly lost due to carbonate formation and the pressure and temperature declined . In Epoch II, the mean annual temperature fell below freezing but peak temperatures would have exceeded freezing . Ice covered lakes, similar to those in the McMurdo Dry Valleys of Antarctica could have provided a habitat for life . In Epoch III, the mean and peak temperatures were below freezing and there would have been only transient liquid water . Microbial ecosystems living in endolithic rock "greenhouses" could have continued to survive . Finally, in Epoch IV, the pressure dropped to near the triple point pressure of water and liquid water could no longer have existed on the surface and life on the surface would have become extinct.

Adv Space Res, 1992, 12(4), 133 - 40
The implantation of life on Mars: feasibility and motivation; Haynes RH et al.; Environmental conditions on Mars are extremely hostile, and would be destructive to any organisms which might arrive there unprotected to-day . However, it is a biocompatible planet . Its unalterable astrophysical parameters would allow the maintenance of a much thicker, warmer carbon dioxide atmosphere than that which currently exists . Though very cold (averaging about -60 degrees C), highly oxidizing and desiccated, Mars may possess substantial quantities of the materials needed to support life--in particular, water and carbon dioxide . A general scenario for implanting life on Mars would include three main phases: (1) robotic and human exploration to determine whether sufficiently large and accessible volatile inventories are available; (2) planetary engineering designed to warm the planet, release liquid water and produce a thick carbon dioxide atmosphere; and (3) if no indigenous Martian organisms emerge as liquid water becomes available, a program of biological engineering designed to construct and implant pioneering microbial communities able to proliferate in the newly clement, though still anaerobic, Martian environment . The process of establishing an ecosystem, or biosphere, on a lifeless planet is best termed 'ecopoiesis.' This new word, derived from Greek, means 'the making of an abode for life.' It is by no means clear whether ecopoiesis on Mars is scientifically possible or technologically achievable . Thus we urge that it be one of the objectives of space research during the next century to assess the feasibility of ecopoiesis on Mars.

Glob Planet Change, 1991, 97, 93 - 6
Microbial mats, stromatolites and the rise of oxygen in the Precambrian atmosphere; Des Marais DJ; Microbial mats are stratified communities that develop within the environmental microgradients established at the interfaces of water and solid substrates (Cohen, 1989) . Stromatolites, the lithified remains of layered accumulations of microbial mats, occur in rocks as old as 3.5 Ga (Lowe, 1980; Walter et al., 1980) . These lithified microbial communities represent the most ancient, widespread ecosystems known, and it is useful to explore their role in the accumulation of free oxygen in the ancient atmosphere.

Palaeontology, 1992, 35(Pt 4), 751 - 74
Vendian microfossils in metasedimentary cherts of the Scotia Group, Prins Karls Forland, Svalbard; Knoll AH; Sedimentary rocks of the Scotia Group, Prins Karls Forland, Svalbard, have been metamorphosed to lower greenschist facies . Yet Scotia chert nodules contain abundant organic-walled microfossils belonging to at least seventeen taxa . Their black colour indicates that the fossils underwent substantial thermal alteration . However, it is suggested that preservation in a matrix of early diagenetic silica shielded them from the most destructive mechanical and chemical effects of metamorphism . Microbial mats and large acanthomorphic acritarchs suggest a coastal marine depositional environment; the acritarchs further indicate an early Vendian age for the sediments . The Scotia fossils bear a close resemblance to assemblages described from the Doushantuo Formation, China and elsewhere, demonstrating the broad geographical distribution of biostratigraphically important Vendian taxa . Briareus and Echinosphaeridium are described as new genera; Briareus borealis is described as a new species, while Echinosphaeridium maximum is proposed as a new combination.

Adv Space Res, 1994, 14(11), 285 - 9
Elevated CO2: impact on diurnal patterns of photosynthesis in natural microbial ecosystems; Rothschild LJ; Algae, including blue-green algae (cyanobacteria), are the major source of fixed carbon in many aquatic ecosystems . Previous work has shown that photosynthetic carbon fixation is often enhanced in the presence of additional carbon dioxide (CO2) . This study was undertaken to determine if this CO2 fertilization effect extended to microbial mats, and, if so, at what times during the day might the addition of CO2 affect carbon fixation . Four microbial mats from diverse environments were selected, including mats from a hypersaline pond (area 5, Exportadora de Sal, Mexico), the marine intertidal (Lyngbya, Laguna Ojo de Liebre, Mexico), an acidic hotspring (Cyanidium, Nymph Creek, Yellowstone National Park), and an acidic stream at ambient temperature (Zygogonium, Yellowstone National Park) . Carbon fixation in the absence of additional CO2 essentially followed the rising and falling sunlight levels, except that during the middle of the day there was a short dip in carbon fixation rates . The addition of CO2 profoundly enhanced carbon fixation rates during the daylight hours, including during the midday dip . Therefore, it is unlikely that the midday dip was due to photoinhibition . Surprisingly, enhancement of carbon fixation was often greatest in the early morning or late afternoon, times when carbon fixation would be most likely to be light limited.

Adv Space Res, 1984, 4(12), 203 - 6
Succession in a microbial mat community: a gaian perspective; Stolz JF; The Gaia hypothesis originally proposed by James E . Lovelock states that the composition, oxidation-reduction state and temperature of the troposphere are actively regulated by the activities of the biota . The gaian concept has been extrapolated to include the composition of surface sediments through the process of biomineralization . The stratified microbial community dominated by the cyanobacterium Microcoleus chthonoplastes is actively involved in the deposition of laminated sediments at Laguna Figueroa, Baja California, Mexico . Unusually heavy rains in the winters of 1979 and 1980 flooded the evaporite flat with up to 3 meters of meteoric water and deposited 5-10 cm of allocthonous sediment . The composition of the microbial community changed as a succession of dominating microbial species ensued, ultimately leading to the recolonization of the surface sediment by the original Microcoleus-dominated community . The resiliency of bacterial communities is suggested to be an important mechanism of gaian control systems.

Geochim Cosmochim Acta, 1993 Aug, 57(16), 3971 - 84
Biogeochemical cycles of carbon, sulfur, and free oxygen in a microbial mat
Canfield DE, Des Marais DJ.
Complete budgets for carbon and oxygen have been constructed for cyanobacterial mats dominated by Microcoleus chthonoplastes from the evaporating ponds of a salt works located in Guerrero Negro, Baja California Sur, Mexico . Included in the budget are measured rates of O2 production, sulfate reduction, and elemental exchange across the mat/brine interface, day and night, at various temperatures and times of the year . We infer from this data the various sinks for O2, as well as the sources of carbon for primary production . To summarize, although seasonal variability exists, a major percentage of the O2 produced during the day did not diffuse out of the mat but was used within the mat to oxidize both organic carbon and the sulfide produced by sulfate reduction . At night, most of the O2 that diffused into the mat was used to oxidize sulfide, with O2 respiration of minor importance . During the day, the internal mat processes of sulfate reduction and O2 respiration generated as much or more inorganic carbon (DIC) for primary production as diffusion into the mat . Also, oxygenic photosynthesis was the most important process of carbon fixation, although anoxygenic photosynthesis may have been important at low light levels during some times of the year . At night, the DIC lost from the mat was mostly from sulfate reduction . Elemental fluxes across the mat/brine interface indicated that carbon with an oxidation state of greater than zero was taken up by the mat during the day and liberated from the mat at night . Overall, carbon with an average oxidation state of near zero accumulated in the mat . Both carbon fixation and carbon oxidation rates varied with temperature by a similar amount . These mats are thus closely coupled systems where rapid rates of photosynthesis both require and fuel rapid rates of heterotrophic carbon oxidation.

Geochim Cosmochim Acta, 1993 Jan, 57(1), 159 - 65
A photoautotrophic source for lycopane in marine water columns; Wakeham SG et al.; Suspended particulate matter and recent sediments from diverse oceanic sites have been investigated for their contents of lycopane . Lycopane was present in all samples, including both oxic and anoxic water column and sediments . The highest concentrations in the water column were found in surface waters of the central Pacific gyre (1.5 ng/L) and in the anoxic waters of the Cariaco Trench (1.1 ng/L) and the Black Sea (0.3 ng/L) . Vertical concentration profiles suggest that lycopane is probably algal in origin . Moreover, biogeochemical conditions in anoxic zones apparently result in a secondary production of lycopane from an as yet unidentified precursor . Compound-specific carbon isotopic analyses have been carried out on lycopane from water column and sediment samples . Isotopic compositions of lycopane range between -23.6% and -32.9% and are consistent with a photoautotrophic origin . We postulate that some lycopane is produced in surface waters of the ocean, while additional lycopane is produced in anoxic zones by anaerobic microbial action on an algal precursor.

Waste Manag Res, 1991 Oct, 9(5), 415 - 23
Potential useful products from solid wastes; Golueke CG et al.; Wastes have been aptly defined as "items, i.e . resources, that have been discarded because their possessors no longer have an apparent use for them" . Accordingly, "wastes" have a significance only in relation to the items and those who have discarded them . The discarded items now are resources awaiting reclamation . Reclamation usually involves either salvage or conversion--or in modern terminology, "reuse" or "recycling" . Reclamation for reuse consists in refurbishing or other upgrading without significantly altering original form and composition . Examples of wastes amenable to reuse are containers (bottles, etc.), cartons and repairable tires . With "recycling" (i.e . conservation), the discarded items are processed such that they become raw material, i.e . resources in the manufacture of "new" products . The variety of processes is wide, ranging from simply physical (grinding) through thermal (melting, gasification, combustion), to biological (composting, biogasification, hydrolysis, microbial protein production) . In the paper, reuse and recycling (conversion) are evaluated in terms of advantages and disadvantages (limitations) and their respective technologies are described and discussed in detail.

Acta Astronaut, 1992 Jul, 27, 219 - 30
Microbial and higher plant biomass selection for closed ecological systems; Tamponnet C et al.; A selection of higher plants and microbial strains is presented with its rationale in order to progressively regenerate food from waste in future space and planetary missions.

Adv Space Res, 1989, 9(8), 117 - 20
Effect of iodine disinfection products on higher plants; Janik D et al.; Iodine is used to disinfect potable water on United States spacecraft . Iodinated potable water will likely be used to grow plants in space . Little is known about the effects of iodine disinfection products on plants . Seeds of select higher plants were germinated in water iodinated using the Shuttle Microbial Check Valve, and water to which measured amounts of iodide was added . Percent germination was decreased in seeds of most species germinated in iodinated water . Beans were most affected . Germination rates, determined from germination half-times, were decreased for beans germinated in iodinated water, and water to which iodide was added . Development was retarded and rootlets were conspicuously absent in bean and several other plant species germinated in iodinated water . Iodide alone did not elicit these responses . Clearly iodine disinfection products can affect higher plants . These effects must be carefully considered for plant experimentation and cultivation in space, and in design and testing of closed environmental life support systems.

Adv Space Res, 1989, 9(6), 167 - 72
Life on Mars: how it disappeared (if it was ever there); Friedmann EI et al.; The cryptoendolithic microbial community in the Ross Desert (McMurdo Dry Valleys) of Antarctica exists at temperatures significantly below the temperature optima of the primary producers . Surviving near the limit of their physiological adaptability, the organisms are under severe environmental stress, so further deterioration in the environment results in cell damage and death . The sequence of events leading to extinction is considered to be a terrestrial analog for disappearance of possible life on early Mars . Progressive stages of cell damage and death in the Ross Desert material are documented with transmission electron microscopy.

Microb Ecol, 1993 Jan-Feb, 25(1), 51 - 69
Long-term productivity in the cryptoendolithic microbial community of the Ross Desert, Antarctica; Friedmann EI et al.; Annual gross productivity of the lichen-dominated cryptoendolithic community was calculated from a computer analysis of photosynthetic response based on laboratory measurements of CO2 exchange and three years (1985-1988) of field nanoclimate data . Photosynthetic optimum increased from -3 to 2 degrees C between irradiance levels of 100 and 1500 micromoles photons m-2 s-1, while the upper compensation point rose from 1 to 17 degrees C . The mean yearly total time available for metabolic activity (temperature above -10 degrees C and moisture present) was 771.3 h for horizontal rock, 421.5 h for northeast-oriented sloped rock, and 1042.2 h for a small depression in horizontal rock (the characteristic site of occasional lichen apothecia) . The calculated mean gross productivity value for a horizontal rock was 1215 mg C m-2 y-1, and net photosynthetic gain was 606 mg C m-2 y-1 . Net ecosystem productivity (annual accretion of cellular biomass) estimated from long-term events amounted to only about 3 mg C m-2 y-1 . The difference between these two values may represent the long-term metabolic costs of the frequent dehydration-rehydration and freezing-thawing cycles or of overwintering, and may account for the leaching of organic substances to the rock . The yearly gross productivity of the cryptoendolithic microbial community of the entire Ross Desert area was estimated at approximately 120,000-180,000 kg C . Of this, 600-900 kg C is in microbial biomass, and much of the rest is soluble compounds that leach into the rocks and possibly percolate to the valleys, providing a source of organic matter for lakes, rivers, and soils.

Orig Life Evol Biosph, 1999 Jan, 29(1), 73 - 93
Post-Viking microbiology: new approaches, new data, new insights; Nealson KH; In the 20 years since the Viking experiments, major advances have been made in the areas of microbial systematics, microbial metabolism, microbial survival capacity, and the definition of environments on earth, suggesting that life is more versatile and tenacious than was previously appreciated . Almost all niches on earth which have available energy, and which are compatible with the chemistry of carbon-carbon bonds, are known to be inhabited by bacteria . The oldest known bacteria on earth apparently evolved soon after the formation of the planet, and are heat loving, hydrogen and/or sulfur metabolizing forms . Among the two microbial domains (kingdoms) is a great deal of metabolic diversity, with members of these forms being able to grow on almost any known energy source, organic or inorganic, and to utilize an impressive array of electron acceptors for anaerobic respiration . Both hydrothermal environments and the deep subsurface environments have been shown to support large populations of bacteria, growing on energy supplied by geothermal energy, thus isolating these ecosystems from the rest of the global biogeochemical cycles . This knowledge, coupled with new insights into the history of the solar system, allow one to speculate on possible evolution and survival of life forms on Mars.

Photochem Photobiol, 1999 Feb, 69(2), 203 - 10
The effects of UV radiation A and B on diurnal variation in photosynthesis in three taxonomically and ecologically diverse microbial mats; Cockell CS et al.; Photosynthetic primary production, the basis of most global food chains, is inhibited by UV radiation . Evaluating UV inhibition is therefore important for assessing the role of natural levels of UV radiation in regulating ecosystem behavior as well as the potential impact of stratospheric ozone depletion on global ecosystems . As both photosynthesis and UV fluxes are subject to diurnal variations, we examined the diurnal variability of the effect of UV radiation on photosynthesis in three diverse algal mats . In one of the mats (Cyanidium caldarium) a small mean decrease in primary productivity over the whole day occurred when both UVA and UVB were screened out . In two of the mats (Lyngbya aestuarii and Zygogonium sp.) we found a mean increase in the total primary productivity over the day when UVB alone was screened and a further increase when UVA and UVB were both screened out . Variations in the effects of UV radiation were found at different times of the day . This diurnal variability may be because even under the same solar radiation flux, there are different factors that may control photosynthetic rate, including nutritional status and other physiological processes in the cell . The results show the importance of assessing the complete diurnal productivity . For some of the time points the increase in the mean was still within the standard deviations in primary productivity, illustrating the difficulty in dissecting UV effects from other natural variations.

Appl Environ Microbiol, 1995 Apr, 61(4), 1551 - 4
Anaerobic electron acceptor chemotaxis in Shewanella putrefaciens; Nealson KH et al.; Shewanella putrefaciens MR-1 can grow either aerobically or anaerobically at the expense of many different electron acceptors and is often found in abundance at redox interfaces in nature . Such redox interfaces are often characterized by very strong gradients of electron acceptors resulting from rapid microbial metabolism . The coincidence of S . putrefaciens abundance with environmental gradients prompted an examination of the ability of MR-1 to sense and respond to electron acceptor gradients in the laboratory . In these experiments, taxis to the majority of the electron acceptors that S . putrefaciens utilizes for anaerobic growth was seen . All anaerobic electron acceptor taxis was eliminated by the presence of oxygen, nitrate, nitrite, elemental sulfur, or dimethyl sulfoxide, even though taxis to the latter was very weak and nitrate and nitrite respiration was normal in the presence of dimethyl sulfoxide . Studies with respiratory mutants of MR-1 revealed that several electron acceptors that could not be used for anaerobic growth nevertheless elicited normal anaerobic taxis . Mutant M56, which was unable to respire nitrite, showed normal taxis to nitrite, as well as the inhibition of taxis to other electron acceptors by nitrite . These results indicate that electron acceptor taxis in S . putrefaciens does not conform to the paradigm established for Escherichia coli and several other bacteria . Carbon chemo-taxis was also unusual in this organism: of all carbon compounds tested, the only positive response observed was to formate under anaerobic conditions.

Appl Environ Microbiol, 1994 Feb, 60(2), 697 - 704
Distribution of cultivated and uncultivated cyanobacteria and Chloroflexus-like bacteria in hot spring microbial mats; Ruff-Roberts AL et al.; Oligodeoxynucleotide hybridization probes were developed to complement specific regions of the small subunit (SSU) rRNA sequences of cultivated and uncultivated cyanobacteria and Chloroflexus-like bacteria, which inhabit hot spring microbial mats . The probes were used to investigate the natural distribution of SSU rRNAs from these species in mats of Yellowstone hot springs of different temperatures and pHs as well as changes in SSU rRNA distribution resulting from 1-week in situ shifts in temperature, pH, and light intensity . Synechococcus lividus Y-7c-s SSU rRNA was detected only in the mat of a slightly acid spring, from which it may have been initially isolated, or when samples from a more alkaline spring were incubated in the more acid spring . Chloroflexus aurantiacus Y-400-fl SSU rRNA was detected only in a high-temperature mat sample from the alkaline Octopus Spring or when lower-temperature samples from this mat were incubated at the high-temperature site . SSU rRNAs of uncultivated species were more widely distributed . Temperature distributions and responses to in situ temperature shifts suggested that some of the uncultivated cyanobacteria might be adapted to high-, moderate-, and low-temperature ranges whereas an uncultivated Chloroflexus-like bacterium appears to have broad temperature tolerance . SSU rRNAs of all uncultivated species inhabiting a 48 to 51 degrees C Octopus Spring mat site were most abundant in the upper 1 mm and were not detected below a 2.5-to 3.5-mm depth, a finding consistent with their possible phototrophic nature . However, the effects of light intensity reduction on these SSU rRNAs were variable, indicating the difficulty of demonstrating a phototrophic phenotype in light reduction experiments.

Appl Environ Microbiol, 1988 Apr, 54(4), 960 - 5
Carbon metabolism of the cryptoendolithic microbiota from the Antarctic desert; Vestal JR; The carbon metabolism of the cryptoendolithic microbiota of sandstones from the Ross Desert of Antarctica was studied in situ and in vitro . Organic and inorganic carbon compounds were metabolized by the microbiota, with bicarbonate incorporation into community lipids occurring primarily in the light . Light intensity affected the photometabolism of carbon with a photosynthesis-intensity response optimum at about 200 to 300 micromoles of photons per m2 per s . Photosynthesis was also affected by temperature, with a minimum activity at -5 degrees C, an optimum activity at 15 degrees C, and complete inhibition at 35 degrees C, indicating that the cryptoendolithic community was psychrophilic . The primary source of CO2 for photosynthesis in situ was the atmosphere . CO2 may also be photometabolized by using the carbon produced from respiration within the endolithic community . Photosynthesis occurred maximally when the microbiota was wet with liquid water and to a lesser extent in a humid atmosphere . This simple microbial community, therefore, exists under extremes of water, light, and temperature stress which affect and control its metabolism.

Appl Environ Microbiol, 1988 Apr, 54(4), 957 - 9
Biomass of the cryptoendolithic microbiota from the Antarctic desert; Vestal JR; Extractable lipid phosphate was used to determine the biomass of the cryptoendolithic microbiota that colonizes sandstone rocks in the Ross Desert region of Antarctica . The mean amount of lipid phosphate was 0.053 micromole/cm2 (n = 9), which equals 2.54 g of C per m2 (range, 1.92 to 3.26 g of C per m2) of biomass in the biotic zone of these rocks . The turnover of phospholipids was comparable to that of temperate sediments and soils (t1/2, 6 to 9 days) at 0 degrees C and a light intensity of 305 micromoles of photons per m2 per s, indicating that this was a good method to measure viable biomass . The biomass was 0.3 to 9.6% of the total carbon content of the biotic zone and was about 2 orders of magnitude smaller than the epilithic lichen dry weight at a location some 7 degrees north in latitude . The cryptoendolithic microbiota had a uniform density throughout the biotic zone under the rock surface . The results indicate that the cryptoendolithic microbial biomass is small but viable in this unique, extreme ecosystem.

Orig Life, 1984, 14(1-4), 671 - 9
The stratified microbial community at Laguna Figueroa, Baja California, Mexico: a possible model for prephanerozoic laminated microbial communities preserved in cherts; Stolz JF et al.; The microbial mat community of the evaporite flat at North Pond, Laguna Figueroa (Baja California, Mexico) was actively involved in the production of laminated sediments prior to 1978 . Heavy rains in 1979 and 1980 flooded the mat with 1 and 3 meters of meteoric water respectively . The flooding deposited up to 10 cm of silicoclastic sediment over the Microcoleus-dominated mat and resulted in the cessation of laminated sediment deposition . In 1982, the surface had been recolonized by species of cyanobacteria (Spirulina, Oscillatoria) and purple photosynthetic bacteria (Chromatium, Thiocapsa) . The silicoclastic sediments and residual evaporites, which overlaid the laminated sediment, had been reworked into an anaerobic, sulfide-rich mud and contained well preserved sheaths of filamentous and coccoid bacteria . The Swaziland Sequence in the Barberton mountain land (which includes the Onverwacht and Fig Tree Group as well as the Swartkoppie zone between them) contains laminated sediments and carbon-rich chert . Structurally preserved microfossils have been found in the smooth black chert but not in the laminae . We concur with others who suggested that the laminated sediments from the Swaziland Sequence were deposited by an active stratified microbial community . However, we propose that these organisms which were preserved were originally buried in the associated sulfide-rich muds and were subsequently silicified.

Science, 1986 Sep 19, 233(4770), 1300 - 3
Seasonal variations in the stable carbon isotopic signature of biogenic methane in a coastal sediment; Martens CS et al.; Systematic seasonal variations in the stable carbon isotopic signature of methane gas occur in the anoxic sediments of Cape Lookout Bight, a lagoonal basin on North Carolina's Outer Banks . Values for the carbon isotope ratio (delta 13C) of methane range from -57.3 per mil during summer to -68.5 per mil during winter in gas bubbles with an average methane content of 95% . The variations are hypothesized to result from changes in the pathways of microbial methane production and cycling of key substrates including acetate and hydrogen . The use of stable isotopic signatures to investigate the global methane cycle through mass balance calculations, involving various sediment and soil biogenic sources, appears to require seasonally averaged data from individual sites.

Nature, 1990 Jun 21, 345(6277), 710 - 2
Model of carbon fixation in microbial mats from 3,500 Myr ago to the present; Rothschild LJ et al.; Biological carbon fixation is an important part of global carbon cycling and ecology . Fixation that took place 3,500 million years ago is recorded in the laminated sedimentary rock structures known as stromatolites, which are fossilized remains of microbial mat communities . Stromatolites are the most abundant type of fossil found in the Proterozoic (2,500 to 590 Myr ago), but they then declined, possibly because of predation and competition . Using modern microbial mats as analogues for ancient stromatolites, we show that the rate of carbon fixation is higher at the greater levels of atmospheric CO2 that were probably present in the past . We suggest that carbon fixation in microbial mats was not carbon-limited during the early Precambrian, but became carbon-limited as the supply of inorganic carbon decreased . Carbon limitation led to a lower rate of carbon fixation, especially towards the end of the Precambrian . Thus, another reason for the decline of the stromatolites could have been a decrease in available CO2.

Eur J Immunol, 2001 Sep, 31(9), 2762 - 70
T cell response to N-formylated peptides in humans; Ristori G et al.; We present the first evidence of a T lymphocyte response to N-formylated peptides in humans . N-formylated peptide sequences from self (mitochondrial) and foreign (microbial) antigens were used to isolate antigen-specific T cell clones from healthy individuals, including a set of monozygotic twins . The observed response differed from that previously described in mouse (CD4(+) phenotype and MHC class II restriction in humans vs . CD8(+) phenotype and class I restriction in mice) . These lymphocytes produce substantial amounts of IFN-gamma . They were isolated in only one of the monozygotic twins, which suggests that their expansion in the healthy immune repertoire is independent of the genetic background . Our result will help in assessing the relevance of N-formylated peptide-specific T cells in protection against infections within the human immune system.

Biomol Eng, 2001 Sep, 18(2), 41 - 7
Engineering novel biocatalytic routes for production of semisynthetic opiate drugs; Boonstra B et al.; The morphine alkaloids and their semisynthetic derivatives provide a diverse range of important pharmaceutical drugs . Current production of semisynthetic opiate drugs is by chemical means from naturally occurring morphine, codeine and thebaine . Although various microbial transformations of morphine alkaloids have been identified since the 1960s, more recently there has been considerable effort devoted to engineering biocatalytic routes for producing these important compounds . Such biocatalytic routes are attractive, as they would provide an alternative to the chemical production processes which suffer from limited supply of precursors, often low yields and toxic wastes . The biotransformation of morphine and codeine to the potent analgesic hydromorphone and the mild analgesic/antitussive hydrocodone, respectively, by recombinant Escherichia coli has been demonstrated and the problems encountered when engineering such a system will be discussed.

J Biol Chem, 2001 Nov 16, 276(46), 43087 - 94 Epub 2001 Aug 30.
Identification of a site on mannan-binding lectin critical for enhancement of phagocytosis; Arora M et al.; Mannan-binding lectin (MBL) constitutes an important part of the human innate immune defense system . It has been shown to mediate the activation of complement upon binding to specific microbial carbohydrate motifs, to directly opsonize organisms, and to enhance the phagocytosis of targets suboptimally opsonized with IgG or complement components C3b or C4b . This enhancement of phagocytic activity induced by MBL and other molecules that contain a collagen-like region contiguous with a pattern recognition domain is mediated by a 126,000 M(r) surface glycoprotein, designated C1qR(P) . Although it has been known that the collagen-like domain of these "defense collagens" contains the interaction site(s) that triggers this enhancement of uptake, the specific interaction site has not been identified . To address this issue, wild type and mutant MBL constructs were generated, inserted into baculovirus, expressed in Sf9 cells, and the recombinant MBL (rMBL) proteins purified by mannan affinity chromatography . The effect of wild type and mutant rMBL on the phagocytosis of targets suboptimally opsonized with IgG or with IgM and C4b by human peripheral blood monocytes was then assessed . Two mutants, one of which has five GXY triplets deleted below the kink region of MBL and the other one having only two of the GXY triplets deleted below the kink, failed to enhance phagocytosis, suggesting the importance of the specific sequence GEKGEP in stimulating phagocytic activity . Similar sequences were detected in other defense collagens, implicating the consensus motif GE(K/Q/R)GEP as critical in mediating the enhancement of phagocytosis through C1qR(P.) Clarification of specific ligand-C1qR(P) interactions should facilitate the investigation of the signal transduction processes involved in the cell activation, as well as provide the basis for the design of specific modulators of the functions mediated by this receptor.

Mol Immunol, 2001 Aug, 38(2-3), 221 - 9
Extrahepatic synthesis of complement proteins in inflammation; Laufer J et al.; The demonstration of local complement protein synthesis leads to speculation as to the biological significance of this phenomenon . A narrative review is provided to illuminate several queries . It is difficult to establish a causal role for the locally produced complement because participation of systemic complement cannot be excluded . It is also difficult to discern whether local complement synthesis is a beneficial response to an inflammatory event or whether it promotes tissue damage . Finally, it remains to be seen if the roles of local and systemic complement differ in these respects . Extrahepatic expression of complement components of the activation pathways may provide a rapid response to microbial invasion . Once produced and activated, these proteins evoke a phlogistic response composed of cells and soluble mediators of inflammation . Many cells, not only synthesize complement proteins, but can also be stimulated via their complement receptors . This positive feedback may enhance local immune defense, especially in organs isolated from plasma components . In addition, local environmental factors in different organs may differentially regulate complement synthesis . These factors may include pro-inflammatory molecules and non-immune effectors, such as tissue ischemia/reoxygenation and drugs . Local complement dysregulation due to inhibition of activity of a complement regulatory component was shown to cause disease and restoration of the capacity to regulate the complement pathway restored health . Extrahepatic complement synthesis may also modulate local cellular responses, as to decrease detrimental damage of the inflammatory reaction . The demonstration that complement proteins play a significant role in the clearance of apoptotic cells suggests that local synthesis and activation of complement may contribute not only to tissue damage but also to tissue repair.

Mol Immunol, 2001 Aug, 38(2-3), 175 - 87
Anaphylatoxins and infectious and non-infectious inflammatory diseases; Kohl J; In recent years a plethora of data has accumulated directing toward an important role of polypeptides C3a and C5a and its degradation product C5adesArg, summarized as anaphylatoxins (ATs), in microbial host defense and immune regulation . The ATs exert their various biologic functions by interacting with specific C3a- and C5a-receptors present on cells of myeloid origin, epithelial cells, smooth muscle cells as well as on activated B- and T-cells . Activation of AT receptors mediates signal transduction pathways triggering a variety of proinflammatory events . However, by interacting with the cytokine- and chemokine network C3a and C5a exhibit also anti-inflammatory properties . In this review the focus is on the pathogenetic role of the ATs in sepsis, immune complex disease, delayed type hypersensitivity and asthma . Discussed are data from animal models in which the ATs are blocked by specific C3a or C5a inhibitors or from mice with genetic deletions of the specific receptors of either C3a or C5a/C5adesArg.

Genome Biol . 2001;2(8):RESEARCH0027 . Epub 2001 Aug 01.
A clustering method for repeat analysis in DNA sequences; Volfovsky N et al.; BACKGROUND: A computational system for analysis of the repetitive structure of genomic sequences is described . The method uses suffix trees to organize and search the input sequences; this data structure has been used previously for efficient computation of exact and degenerate repeats . RESULTS: The resulting software tool collects all repeat classes and outputs summary statistics as well as a file containing multiple sequences (multi fasta), that can be used as the target of searches . Its use is demonstrated here on several complete microbial genomes, the entire Arabidopsis thaliana genome, and a large collection of rice bacterial artificial chromosome end sequences . CONCLUSIONS: We propose a new clustering method for analysis of the repeat data captured in suffix trees . This method has been incorporated into a system that can find repeats in individual genome sequences or sets of sequences, and that can organize those repeats into classes . It quickly and accurately creates repeat databases from small and large genomes . The associated software (RepeatFinder), should prove helpful in the analysis of repeat structure for both complete and partial genome sequences.

Prikl Biokhim Mikrobiol, 2001 Jul-Aug, 37(4), 429 - 35
{A two-stage technique for producing the microbial exopolysaccaride ethapolan with improved rheological properties}; Pirog TP et al.; A two-stage technique was proposed for cultivating producers of microbial exopolysaccharide ethapolan . The practical value of ethapolan is determined by its rheological properties . The use of a formaldehyde-supplemented medium at the second stage of cultivation improved the rheological properties of ethapolan without reducing its yield . This effect of formaldehyde was due to its binding to the exopolysaccharide, which altered the molecular-mass characteristics of the latter and protected the cells against the toxic action of formaldehyde . At all stages of its purification, ethapolan had improved rheological properties, suggesting that it was tightly bound to formaldehyde.

Prikl Biokhim Mikrobiol, 2001 Jul-Aug, 37(4), 405 - 12
{The treatment industrial sewage of nonferrous heavy metals using biosorbents}; Zakharova VI et al.; Producers of the antibiotics neomycin and lincomycin were most potent in sorbing nonferrous metals; they removed 99% Zn and Cd and 95% Ni . The degree of metal sorption increased with an increase in solution pH and calcium content in the biomass . Dynamic studies of biosorbents prepared from microbial biomass showed that neomycin industrial waste products are highly efficient in treating galvanic washing water . The total dynamic exchange capacities by nickel and cadmium were 6.85 and 7.16 mg/ml, respectively.

Environ Sci Technol, 2001 Aug 15, 35(16), 3310 - 3
The absence and application of stable carbon isotopic fractionation during the reductive dechlorination of polychlorinated biphenyls; Drenzek NJ et al.; A bacterial enrichment culture (specific to doubly flanked chlorine removal) reductively dechlorinated 2,3,4,5-tetrachlorobiphenyl (2,3,4,5-CB) to 2,3,5-trichlorobiphenyl (2,3,5-CB) in aqueous media . Approximately 90% conversion to 2,3,5-CB occurred after 90 days, with no other products formed . The delta13C values of 2,3,4,5-CB and 2,3,5-CB were relatively constant over the course of the reaction, indicating a very small or no isotope effect . In addition, compound-specific delta13C analysis performed for every congener in three different lots of Aroclor 1268 showed an intrinsic isotopic trend of decreasing 13C abundance with increasing chlorine content, similar to observations in other commercial mixtures of polychlorinated biphenyls (PCBs) . The results of this laboratory study suggest that microbial reductive dechlorination of PCBs in contaminated sediments will create congeners with more depleted delta13C values than native PCBs of similar chlorination . Such information may provide additional evidence for the occurrence of this process and aid in further understanding the biogeochemistry of these compounds.

Environ Sci Technol, 2001 Aug 15, 35(16), 3302 - 9
Rapid oxidation of arsenite in a hot spring ecosystem, Yellowstone National Park; Langner HW et al.; Geothermal springs within Yellowstone National Park (YNP) often contain arsenic (As) at concentrations of 10-40 microM, levels that are considered toxic to many organisms . Arsenite (As(III)) is often the predominant valence state at the point of discharge but is rapidly oxidized to arsenate (As(V)) during transport in shallow surface water . The current study was designed to establish rates and possible mechanisms of As(III) oxidation and to characterize the geochemical environment associated with predominant microbial mats in a representative acid-sulfate-chloride (pH 3.1) thermal (58-62 degrees C) spring in Norris Basin, YNP . At the spring origin, total soluble As was predominantly As(III) at concentrations of 33 microM . No oxidation of As(III) was detected over the first 2.7 m downstream from the spring source, corresponding to an area dominated by a yellow filamentous S0-rich microbial mat However, rapid oxidation of As(III) to As(V) was observed between 2.7 and 5.6 m, corresponding to termination of the S0-rich mats, decreases in dissolved sulfide, and commencement of a brown Fe/As-rich mat . Rates of As(II) oxidation were estimated, yielding an apparent first-order rate constant of 1.2 min(-1) (half-life = 0.58 min) . The oxidation of As(III) was shown to require live organisms present just prior to and within the Fe/As-rich mat . Complementary analytical tools used to characterize the brown mat revealed an As:Fe molar ratio of 0.7 and suggested that this filamentous microbial mat contains iron(III) oxyhydroxide coprecipitated with As(V) . Results from the current work are the first to provide a comprehensive characterization of microbially mediated As(III) oxidation and the geochemical environments associated with microbial mats in acid-sulfate-chloride springs of YNP.

Behav Genet, 2001 Jan, 31(1), 39 - 46
Identifying genetic influences on sleep: an approach to discovering the mechanisms of sleep regulation; Toth LA; Comparisons of sleep patterns of various inbred strains of mice have revealed differences in daily amounts of slow-wave sleep and rapid-eye movement sleep, in circadian patterns of sleep, and in some parameters of the electroencephalograms both in healthy mice and in mice undergoing microbial infections . Technical considerations will probably be an important variable in achieving consensus between different independent studies that use a genetic approach to identify sleep-regulatory genes or mechanisms . However, despite such differences, current data suggest that both normal sleep and various sleep disorders either have a genetic basis or are influenced by genetically determined physiologic or environmental predispositions . Excessive sleepiness, abnormal sleep patterns, nonrestorative sleep, and fatigue are becoming increasingly pervasive in modern society . Identifying genes that influence vigilance may ultimately contribute to a better understanding of the processes that control normal sleep and contribute to sleep disorders and may eventually promote the development of interventions to prevent or alleviate these disabling medical conditions.

J Environ Monit, 1999 Oct, 1(5), 445 - 52
Determination of selected microbial volatile organic compounds by diffusive sampling and dual-column capillary GC-FID--a new feasible approach for the detection of an exposure to indoor mould fungi?
Elke K, Begerow J, Oppermann H, Kramer U, Jermann E, Dunemann L.
A new, analytically valid procedure is described to assess the exposure of human beings to the so-called microbial volatile organic compounds (MVOCs) in air . The method can be used routinely for large sample numbers and is especially valuable as a basis for further research on the correlation between single MVOCs and indoor mould growth . The procedure is based on the fact that fungi produce a variety of volatile organic compounds, such as 3-methylbutan-1-ol, 3-methylbutan-2-ol, fenchone, heptan-2-one, hexan-2-one, octan-3-one, octan-3-ol, pentan-2-ol, alpha-terpineol, and thujopsene, which they emit into the indoor environment . Using diffusive samplers, these MVOCs are adsorbed onto charcoal during a sampling interval of four weeks . The described method is thus superior to existing methods which use short-term active sampling . After desorption with carbon disulfide, the MVOCs were determined by dual-column gas chromatography with flame ionization detection using the large-volume injection technique for sample introduction . The detection limits ranged between 0.15 and 0.53 microgram m-3, within-series precision was found to range between 6.5 and 19.0%, and recovery was between 77 and 118% . The procedure has been successfully applied in the context of a large field study to measure the indoor MVOC exposure in children's rooms of 132 dwellings . The objective of the study was to examine the relation between indoor mould growth, the indoor MVOC exposure and the prevalence of adverse health effects . Information about mould formation has been obtained by a questionnaire and by the determination of colony forming units of mould fungi in mattress dust . With the exception of 3-methylbutan-2-ol, fenchone, nonan-2-one, octan-2-one, and thujopsene, indoor air concentrations of all MVOCs under investigation were significantly higher inside damp and mouldy dwellings . From the primary MVOCs under investigation, 3-methylbutan-1-ol, hexan-2-one, heptan-2-one, and octan-3-ol were found to be most reliable indicators for mould formation . A correlation was also found between selected MVOCs and the occurrence of mould species in mattress dust . Aspergillus sp . correlated with heptan-2-one, hexan-2-one, octan-3-ol, octan-3-one, and alpha-terpineol, while the occurrence of Eurotium sp . was correlated with higher indoor air concentrations of 3-methylbutan-1-ol, 3-methylbutan-2-ol, heptan-2-one, hexan-2-one, octan-3-ol, and thujopsene . Children living in dwellings with elevated MVOC levels had a higher prevalence of asthma, hay fever, wheezing, and irritations of the eyes . These positive associations persisted after controlling for confounding factors such as age, sex, body-mass index, number of siblings, social status, passive smoking, type of heating, and ventilation habits . However, they were not statistically significant . This lack of significance may be a result of the small number of investigated samples.

Am J Public Health, 2001 Sep, 91(9), 1358 - 61
The precautionary principle also applies to public health actions; Goldstein BD; The precautionary principle asserts that the burden of proof for potentially harmful actions by industry or government rests on the assurance of safety and that when there are threats of serious damage, scientific uncertainty must be resolved in favor of prevention . Yet we in public health are sometimes guilty of not adhering to this principle . Examples of actions with unintended negative consequences include the addition of methyl tert-butyl ether to gasoline in the United States to decrease air pollution, the drilling of tube wells in Bangladesh to avoid surface water microbial contamination, and villagewide parenteral antischistosomiasis therapy in Egypt . Each of these actions had unintended negative consequences . Lessons include the importance of multidisciplinary approaches to public health and the value of risk-benefit analysis, of public health surveillance, and of a functioning tort system-all of which contribute to effective precautionary approaches.

Dent Update, 2001 Jul-Aug, 28(6), 274 - 81
Periodontal diseases in children and adolescents: 2 . Management; Clerehugh V et al.; Many of the periodontal diseases affecting children and adolescents can be successfully managed in general dental practice . The decision to treat the young patient in the practice setting or to refer to a periodontal specialist will depend on the complexity of treatment, patient factors and the expertise of the practitioner . Treatment should be provided in three phases: the initial cause-related phase is aimed at controlling microbial plaque; the corrective phase is intended to restore function and aesthetics; supportive periodontal therapy is aimed at preventing recurrence and progression of periodontal disease . Even in cases requiring specialist referral, the dental team in general practice has a key role in the initial and supportive phases of therapy.

Nat Immunol, 2001 Sep, 2(9), 835 - 41
TIRAP: an adapter molecule in the Toll signaling pathway; Horng T et al.; Mammalian Toll-like receptors (TLRs) recognize conserved products of microbial metabolism and activate NF-kappa B and other signaling pathways through the adapter protein MyD88 . Although some cellular responses are completely abolished in MyD88-deficient mice, TLR4, but not TLR9, can activate NF-kappa B and mitogen-activated protein kinases and induce dendritic cell maturation in the absence of MyD88 . These differences suggest that another adapter must exist that can mediate MyD88-independent signaling in response to TLR4 ligation . We have identified and characterized a Toll-interleukin 1 receptor (TIR) domain-containing adapter protein (TIRAP) and have shown that it controls activation of MyD88-independent signaling pathways downstream of TLR4 . We have also shown that the double-stranded RNA-binding protein kinase PKR is a component of both the TIRAP- and MyD88-dependent signaling pathways.

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