Microbial

Proc Natl Acad Sci U S A, 1997 Dec 23, 94(26), 14948 - 53
Leaf-specifically expressed genes for polypeptides destined for chloroplasts with domains of sigma70 factors of bacterial RNA polymerases in Arabidopsis thaliana; Isono K et al.; Genes for sigma-like factors of bacterial-type RNA polymerase have not been characterized from any multicellular eukaryotes, although they probably play a crucial role in the expression of plastid photosynthesis genes . We have cloned three distinct cDNAs, designated SIG1, SIG2, and SIG3, for polypeptides possessing amino acid sequences for domains conserved in sigma70 factors of bacterial RNA polymerases from the higher plant Arabidopsis thaliana . Each gene is present as one copy per haploid genome without any additional sequences hybridized in the genome . Transient expression assays using green fluorescent protein demonstrated that N-terminal regions of the SIG2 and SIG3 ORFs could function as transit peptides for import into chloroplasts . Transcripts for all three SIG genes were detected in leaves but not in roots, and were induced in leaves of dark-adapted plants in rapid response to light illumination . Together with results of our previous analysis of tissue-specific regulation of transcription of plastid photosynthesis genes, these results indicate that expressed levels of the genes may influence transcription by regulating RNA polymerase activity in a green tissue-specific manner.

Proc Natl Acad Sci U S A, 1997 Dec 23, 94(26), 14759 - 63
Cloning and mutagenesis of a herpesvirus genome as an infectious bacterial artificial chromosome; Messerle M et al.; A strategy for cloning and mutagenesis of an infectious herpesvirus genome is described . The mouse cytomegalovirus genome was cloned and maintained as a 230 kb bacterial artificial chromosome (BAC) in E . coli . Transfection of the BAC plasmid into eukaryotic cells led to a productive virus infection . The feasibility to introduce targeted mutations into the BAC cloned virus genome was shown by mutation of the immediate-early 1 gene and generation of a mutant virus . Thus, the complete construction of a mutant herpesvirus genome can now be carried out in a controlled manner prior to the reconstitution of infectious progeny . The described approach should be generally applicable to the mutagenesis of genomes of other large DNA viruses.

J Interferon Cytokine Res, 1997 Dec, 17(12), 781 - 8
Interleukin-10 functions in vitro and in vivo to inhibit bacterial DNA-induced secretion of interleukin-12; Anitescu M et al.; Bacterial DNA (bDNA) has a number of biologic properties, including the ability to induce interleukin-12 (IL-12) production by macrophages . We studied the role of the regulatory cytokine IL-10 as a potential inhibitor of bDNA-induced IL-12 production . IL-10 concentrations as low as 0.3 ng/ml profoundly inhibited bDNA-induced macrophage IL-12 production as measured by Elispot analysis of IL-12 p40-secreting cells . Additionally, we found that IL-10 inhibited bDNA-induced IL-12 secretion by the macrophage cell lines J774 and RAW 264 . Preincubation of splenic adherent cells with IL-10 markedly reduced bDNA-induced transcription of IL-12 p40 mRNA . Interestingly, after 2 h of exposure, bDNA also induces transcription of IL-10 mRNA by splenic adherent cells . The importance of IL-10 in the in vivo regulation of bDNA-induced cytokine secretion was illustrated by the response of mice with disrupted IL-10 genes (IL-10 ko mice) to i.v . bDNA challenge . Compared to +/+ mice, IL-10 knockout (ko) mice exhibited increased numbers of IL-12 and interferon-gamma (IFN-gamma)-secreting cells following either single or repeated challenge with bDNA . These findings indicate that IL-10 plays a key role in regulating bDNA-induced production of inflammatory cytokines.

J Clin Gastroenterol, 1997 Dec, 25(4), 688 - 90
Pneumoperitoneum and ascites secondary to bacterial overgrowth; Raju GS et al.; Abdominal bloating, weight loss, pneumoperitoneum, and ascites developed in a 73-year-old woman . She had scleroderma, megajejunum, small bowel dysmotility, and bacterial overgrowth . After treatment with a course of antibiotics, the pneumoperitoneum and ascites resolved, but her symptoms and the pneumoperitoneum recurred after the antibiotics were stopped . She was placed on cyclical antibiotics, and during a 2-year follow-up period she has remained well . The pneumoperitoneum and ascites may have been secondary to small bowel bacterial overgrowth . Ours is the first case that demonstrates this association.

Biophys J, 1998 Jan, 74(1), 569 - 75
Quasi- and nonequivalence in the structure of bacterial flagellar filament; Hasegawa K et al.; In supercoiled forms of flagellar filaments, which are thought to be produced by combinations of two distinct subunit lattices, the lattices are elastically deformed in 11 different ways, depending on their azimuthal positions on the circumference of a tube with 11 protofilaments . Those two interactions are nonequivalent as opposed to quasiequivalent ones in elastically deformed lattices of otherwise identical interactions . The term nonequivalence is defined to represent different bonding interactions, and quasiequivalent is used to describe deformed but conserved bonding interactions . By using two distinct lattices that were accurately determined by x-ray fiber diffraction, 10 possible supercoiled forms of flagellar filaments were simulated, based on a bistable-subunit packing model . Comparison to the observed forms showed good agreement, indicating that the model and determined lattice parameters effectively represent realistic features of the structure . The simulated quasiequivalent lattices have been compared to the two nonequivalent lattices, revealing an interesting feature: the maximum deviation in the intersubunit distance by elastic deformation is almost three-quarters of the difference between the two distinct lattices, demonstrating a balanced coexistence of a well-defined conformational distinction and extensive adaptability in the molecular structure of flagellin and its packing interactions.

Biophys J, 1998 Jan, 74(1), 182 - 91
Reorganization energy of the initial electron-transfer step in photosynthetic bacterial reaction centers; Parson WW et al.; The reorganization energy (lambda) for electron transfer from the primary electron donor (P*) to the adjacent bacteriochlorophyll (B) in photosynthetic bacterial reaction centers is explored by molecular-dynamics simulations . Relatively long (40 ps) molecular-dynamics trajectories are used, rather than free energy perturbation techniques . When the surroundings of the reaction center are modeled as a membrane, lambda for P* B --> P+ B- is found to be approximately 1.6 kcal/mol . The results are not sensitive to the treatment of the protein's ionizable groups, but surrounding the reaction center with water gives higher values of lambda (approximately 6.5 kcal/mol) . In light of the evidence that P+ B- lies slightly below P* in energy, the small lambda obtained with the membrane model is consistent with the speed and temperature independence of photochemical charge separation . The calculated reorganization energy is smaller than would be expected if the molecular dynamics trajectories had sampled the full conformational space of the system . Because the system does not relax completely on the time scale of electron transfer, the lambda obtained here probably is more pertinent than the larger value that would be obtained for a fully equilibrated system.

J Immunol Methods, 1997 Nov 10, 209(1), 75 - 83
Retrieval of phage displayed scFv fragments using direct bacterial elution; Wind T et al.; Phage displayed repertoires of antibody fragments, either single chain Fv (scFv) or Fab, have become a real alternative to traditional hybridoma technology in the generation of monoclonal antibodies . The steps usually taken in the selection from such repertoires were analysed and the necessity of chemical elution of bound phage-Abs and precipitation of amplified phage particles questioned . By using a semi-synthetic scFv library as a source, phage antibodies recognising a panel of seven antigens were isolated utilising direct bacterial elution of bound phage . Selections against two antigens were subsequently performed with bacterial or chemical elution in parallel and the resulting pools of phage antibodies compared . It is demonstrated that direct bacterial elution can be used when selecting from phage displayed antibody repertoires but that the enrichment of high affinity binders might be jeopardised . In addition, a simplified and more rapid scheme for amplification and use of phage displayed repertoires is described.

Trends Microbiol, 1997 Dec, 5(12), 496 - 501
Bacterial associations with mycorrhizal fungi: close and distant friends in the rhizosphere; Perotto S et al.; Bacteria and mycorrhizal fungi in the rhizosphere interact with each other at different levels of cellular integration, ranging from apparently simple association, through surface attachment, to intimate and obligatory symbiosis . This synergism may not only be important in promoting plant growth and health, but may also be significant to rhizosphere ecology.

Am J Surg, 1998 Jan, 175(1), 38 - 43
Gut bacterial translocation during total parenteral nutrition in experimental rats and its countermeasure; Nakasaki H et al.; BACKGROUND: The use of total parenteral nutrition (TPN) is commonly associated with mucosal lining of the intestinal tract, causing degenerative changes within the gut-associated lymphoid tissue (GALT) . These phenomena are probably caused by the translocation of indigenous intestinal bacteria into other organs and tissues where they induce infections . METHODS: Using TPN model rats, this paper looks at the result of the investigation of the action of PSK (proteoglycan), a biological response modifier, which appears to suppress bacterial translocation and maintain local immunity activity . RESULTS: Culture of mesenteric lymph nodes obtained post-TPN demonstrate a bacterial rate as high as 60% . Immunohistochemical examination indicates a reduction in the number of plasma cells and a decrease in S-IgA production and secretion . A similar reduction in S-IgA within bile and portal venous blood was also confirmed . Continuous oral administration of PSK in a daily dose of 1,000 mg/kg had a protective effect against the degeneration of GALT . A staining in immunocytes of Peyer's patches using immunohistochemical study was performed after administration of PSK and revealed constant levels of MHC-I, MHC-II, T helper cells, and interleukin-2 producing cells, supporting the protective role of PSK against degeneration of GALT with a subsequent reduction in bacterial translocation . CONCLUSIONS: Proteoglycan can restore the impaired local immunity in the intestinal tract to normal levels and suppression of the bacterial translocation to provide an important function for patients receiving TPN treatment.

Neurology, 1998 Jan, 50(1), 196 - 203
Recent bacterial and viral infection is a risk factor for cerebrovascular ischemia: clinical and biochemical studies; Grau AJ et al.; We performed a case-control study to investigate the role of recent infection as stroke risk factor and to identify pathogenetic pathways linking infection and stroke . We examined 166 consecutive patients with acute cerebrovascular ischemia and 166 patients hospitalized for nonvascular and noninflammatory neurologic diseases . Control subjects were individually matched to patients for sex, age, and season of admission . We assessed special biochemical parameters in subgroups of stroke patients with and without recent infection (n = 21) who were similar with respect to demographic and clinical parameters . Infection within the preceding week was a risk factor for cerebrovascular ischemia in univariate (odds ratio {OR} 3.1; 95% confidence interval (CI), 1.57 to 6.1) and age-adjusted multiple logistic regression analysis (OR 2.9; 95% CI, 1.31 to 6.4) . The OR of recent infection and age were inversely related . Both bacterial and viral infection contributed to increased risk . Infection elevated the risk for cardioembolism and tended to increase the risk for arterioarterial embolism . Stroke patients with and without preceding infection were not different with respect to factor VII and factor VIII activity, fibrin monomer, fibrin D-dimer, von Willebrand factor, C4b-binding protein, protein S, anticardiolipin antibodies, interleukin-1 receptor antagonist, soluble tumor necrosis factor-alpha receptor, interleukin-6, interleukin-8, and neopterin . In conclusion, recent infection is an independent risk factor for acute cerebrovascular ischemia . Its role appears to be more important in younger age groups . The pathogenetic linkage between infection and stroke is still insufficiently understood.

Pediatr Pulmonol Suppl, 1997, 16, 88 - 9
Influence of viral and bacterial respiratory infections on exacerbations and symptom severity in childhood asthma; Johnston SL; The recent development of PCR for the diagnosis of respiratory viral infection has highlighted the importance of these infections in acute exacerbations of asthma . Rhinoviruses are important in all age groups, but particularly over 1 yr, while the role of RSV in bronchiolitis and wheezing in infants has been reaffirmed . Recent studies using the same technique for the detection of C . pneumoniae suggest a high prevalence of chronic infection in asthmatic children, and that the immune response to this organism may play a pathological role . These studies now require confirmation with larger carefully controlled studies.

Annu Rev Cell Dev Biol, 1997, 13, 457 - 512
The two-component signaling pathway of bacterial chemotaxis: a molecular view of signal transduction by receptors, kinases, and adaptation enzymes; Falke JJ et al.; The chemosensory pathway of bacterial chemotaxis has become a paradigm for the two-component superfamily of receptor-regulated phosphorylation pathways . This simple pathway illustrates many of the fundamental principles and unanswered questions in the field of signaling biology . A molecular description of pathway function has progressed rapidly because it is accessible to diverse structural, biochemical, and genetic approaches . As a result, structures are emerging for most of the pathway elements, biochemical studies are elucidating the mechanisms of key signaling events, and genetic methods are revealing the intermolecular interactions that transmit information between components . Recent advances include (a) the first molecular picture of a conformational transmembrane signal in a cell surface receptor, (b) four new structures of kinase domains and adaptation enzymes, and (c) significant new insights into the mechanisms of receptor-mediated kinase regulation, receptor adaptation, and the phospho-activation of signaling proteins . Overall, the chemosensory pathway and the propulsion system it regulates provide an ideal system in which to probe molecular principles underlying complex cellular signaling and behavior.

J Biol Chem, 1998 Jan 23, 273(4), 2078 - 89
Sesquiterpene synthases from grand fir (Abies grandis) . Comparison of constitutive and wound-induced activities, and cDNA isolation, characterization, and bacterial expression of delta-selinene synthase and gamma-humulene synthase; Steele CL et al.; Grand fir (Abies grandis) has been developed as a model system for the study of oleoresin production in response to stem wounding and insect attack . The turpentine fraction of the oleoresin was shown to contain at least 38 sesquiterpenes that represent 12.5% of the turpentine, with the monoterpenes comprising the remainder . Assays of cell-free extracts from grand fir stem with farnesyl diphosphate as substrate indicated that the constitutive sesquiterpene synthases produced the same sesquiterpenes found in the oleoresin and that, in response to wounding, only two new products were synthesized, delta-cadinene and (E)-alpha-bisabolene . A similarity based cloning strategy yielded two new cDNA species from a stem cDNA library that, when expressed in Escherichia coli and the gene products subsequently assayed, yielded a remarkable number of sesquiterpene products . The encoded enzymes have been named delta-selinene synthase and gamma-humulene synthase based on the principal products formed; however, each enzyme synthesizes three major products and produces 34 and 52 total sesquiterpenes, respectively, thereby accounting for many of the sesquiterpenes of the oleoresin . The deduced amino acid sequence of the delta-selinene synthase cDNA open reading frame encodes a protein of 581 residues (at 67.6 kDa), whereas that of the gamma-humulene synthase cDNA encodes a protein of 593 residues (at 67.9 kDa) . The two amino acid sequences are 83% similar and 65% identical to each other and range in similarity from 65 to 67% and in identity from 43 to 46% when compared with the known sequences of monoterpene and diterpene synthases from grand fir . Although the two sesquiterpene synthases from this gymnosperm do not very closely resemble terpene synthases from angiosperm species (52-56% similarity and 26-30% identity, there are clustered regions of significant apparent homology between the enzymes of these two plant classes . The multi-step, multi-product reactions catalyzed by the sesquiterpene synthases from grand fir are among the most complex of any terpenoid cyclase thus far described.

Genomics, 1997 Dec 15, 46(3), 480 - 2
A mammalian homolog of the bacterial monomeric sarcosine oxidases maps to mouse chromosome 11, close to Cryba1; Herbst R et al.; We have cloned a cDNA from a mouse gene, Pso (peroxisomal sarcosine oxidase) . Pso appears to encode a homolog of the single-subunit (40 kDa) bacterial sarcosine oxidases . The mouse Pso gene product would contain a peroxisomal localization sequence, like that of the recently reported rabbit enzyme, Mouse Pso lies between 20 and 50 kb upstream of the promoter of the Sez6 gene, close to Crybal on chromosome 11 . Pso is expressed very strongly and specifically in liver and kidney . The gene appears to be present widely in eutherian mammals.

Klin Khir, 1997, (5-6), 7 - 11
{The choice of surgical strategies in bacterial infections of the transplants after the reconstructive surgery of the aorto-femoral segment}; Dominiak AB; The experience of the purulent complications treatment occurring while synthetic prosthesis application in the aorto-femoral region and venous shunts-in femoral-popliteal zone is presented . Reconstructive procedures on the abdominal aorta and peripheral arteries were conducted in 4462 patients of whom in 158 (3.5%) the transplant infecting occurred . All the patients were divided conventionally on three groups: with local and total infecting of the transplant and with angiogenic sepsis . New methods of reoperative procedures depending on the infecting kind were proposed . Application of the surgical tactics elaborated for the transplant infecting on aorto-ileal and femoral-popliteal levels have permitted to reduce the lethality from 49.8 to 13.2%, to save the life in 158 (75.5%) patients and to achieve the lower extremities revascularization.

Brain Res, 1997 Nov 14, 775(1-2), 63 - 73
Differential expression of fibronectin, tenascin-C and NCAMs in cultured hippocampal astrocytes activated by kainate, bacterial lipopolysaccharide or basic fibroblast growth factor; Mahler M et al.; Different reports demonstrated that reactive glial cells express increased amounts of adhesion and matrix molecules . Despite a wealth of information on the expression of these molecules during development and after lesion, very little is known of how this expression is regulated . In the present report we used Western blots and immunocytochemistry to investigate the expression of neural cell adhesion molecule (NCAM), fibronectin and tenascin-C in cultured astrocytes from rat hippocampus . The effects of three different extracellular signals were analyzed: the glutamatergic receptor agonist kainic acid, the basic fibroblast growth factor (bFGF) and the bacterial lipopolysaccharide . Each treatment had a specific pattern of glial activation and differentially modified the expression of these proteins . Treatment of astrocytes with kainic acid resulted in an increase of tenascin-C, a decrease of fibronectin and a shift of NCAMs isoforms: NCAM 140 and PSA-NCAM (polysialic acid-rich NCAMs) were increased while NCAM 120 was decreased, bFGF increased fibronectin, tenascin-C and NCAM 120, while decreasing PSA-NCAM . Finally, the treatment of astrocytes with lipopolysaccharide induced a significant increase of fibronectin, tenascin-C and NCAM 120 but did not modify the expression of NCAM 140 and PSA-NCAM . These data suggest different mechanisms for modulation of cell surface interactions . They suggest that glial activation by bFGF and lipopolysaccharide are associated with an increase of the adhesive properties, while kainate action is rather associated with a decrease of the adhesiveness of astrocytes.

Biochemistry, 1997 Dec 23, 36(51), 16247 - 58
Redox thermodynamics of the native and alkaline forms of eukaryotic and bacterial class I cytochromes c; Battistuzzi G et al.; The reduction potentials of beef heart cytochrome c and cytochromes c2 from Rhodopseudomonas palustris, Rhodobacter sphaeroides, and Rhodobacter capsulatus were measured through direct electrochemistry at a surface-modified gold electrode as a function of temperature in nonisothermal experiments carried out at neutral and alkaline pH values . The thermodynamic parameters for protein reduction (DeltaS degrees rc and DeltaH degrees rc) were determined for the native and alkaline conformers . Enthalpy and entropy terms underlying species-dependent differences in E degrees and pH- and temperature-induced E degrees changes for a given cytochrome were analyzed . The difference of about +0.1 V in E degrees between cytochromes c2 and the eukaryotic species can be separated into an enthalpic term (-DeltaDeltaH degrees rc/F) of +0.130 V and an entropic term (TDeltaDeltaS degrees rc/F) of -0.040 V . Hence, the higher potential of the bacterial species appears to be determined entirely by a greater enthalpic stabilization of the reduced state . Analogously, the much lower potential of the alkaline conformer(s) as compared to the native species is by far enthalpic in origin for both protein families, and is largely determined by the substitution of Met for Lys in axial heme ligation . Instead, the biphasic E degrees /temperature profile for the native cytochromes is due to a difference in reduction entropy between the conformers at low and high temperatures . Temperature-dependent 1H NMR experiments suggest that the temperature-induced transition also involves a change in orientation of the axial methionine ligand with respect to the heme plane.

Sex Transm Dis, 1998 Jan, 25(1), 24 - 7
Accuracy of cervical/vaginal cytology in the diagnosis of bacterial vaginosis; Giacomini G et al.; BACKGROUND AND OBJECTIVES: The cytological pattern of bacterial vaginosis (BV) in the Papanicolaou smear has a controversial history (coccoid vs . Gardnerella type) that has not allowed an efficient use of cervical/vaginal cytology in the diagnosis of this condition . Our study is an attempt to clarify this topic . GOALS: To evaluate the accuracy of cervical/vaginal cytology in the diagnosis of BV . STUDY DESIGN: 1,896 separate examinations were performed on 1,471 women attending our sexually transmitted diseases center between 1990 and 1993 . Amsel's composite clinical criteria were used as a gold standard . The Pap smear was prepared on two slides with the addition of a vaginal specimen . RESULTS: In the 166 cases of BV, sensitivity is 88.7%, and specificity is 98.8% . Positive predictive value is 89.8, and negative predictive value is 98.7 . Kendall's correlation coefficient is 0.88 (p < 0.001) . CONCLUSIONS: Our findings support the validity of the vaginal Pap smear in diagnosing BV and suggest the screening of such a disease.

JPEN J Parenter Enteral Nutr, 1998 Jan-Feb, 22(1), 37 - 41
Elemental diet-induced bacterial translocation associated with systemic and intestinal immune suppression; Xu D et al.; BACKGROUND: Elemental diets can lead to a loss of intestinal barrier function, promote bacterial translocation, and impair host immune defenses . The purpose of this study was to determine the effects of i.v . and orally administered total parenteral nutrition (TPN) solution on systemic and intestinal immunity and to establish whether supplemental cellulose fiber could improve the impaired immune response . METHODS: The incidence of bacterial translocation and immune function was quantitated by measuring organ weights, immune cell population levels, and the mitogenic response of lymphocytes from the spleen, mesenteric lymph nodes and Peyer's patches of rats receiving parenteral or enteral TPN solution, with and without fiber supplementation . RESULTS: Parenteral and enterally administered TPN solution promoted bacterial translocation to the mesenteric lymph nodes, reduced immune cell population levels, and decreased the lymphocyte mitogenic response to T- and B-cell mitogens . Supplemental cellulose fiber reduced the incidence of diet-induced bacterial translocation from 84% to 31% (p < .01) and improved immune cell function . To more closely examine the relationship between bacterial translocation and impaired lymphocyte mitogenic activity, rats receiving TPN orally or i.v . were separated into two groups based on whether or not bacterial translocation occurred . Rats in which fiber prevented bacterial translocation had normal mitogenic responses, whereas the sub-group of rats in which fiber failed to prevent bacterial translocation had profound decreases in their lymphocyte mitogenic responses . CONCLUSIONS: Both parenteral and enteral elemental diets induced bacterial translocation and impaired systemic and intestinal immune function . Fiber supplementation was effective in reducing elemental diet-induced bacterial translocation and significantly prevented diet-induced impairment of lymphocyte function.

Arerugi, 1997 Nov, 46(11), 1132 - 5
{Influence of beclomethason dipropionate inhalation therapy on respiratory bacterial infection in patient with an asthmatic attack}; Watanabe Y et al.; The aim of this clinical study was to investigate the influence of beclomethasone dipropionate (BDP) inhalation therapy on respiratory bacterial infection in patient with an asthmatic attack . We studied 267 asthmatic attack episodes of 241 patients with/without BDP inhalation therapy . There was no difference between two groups in %peak flow, body temperature, CRP, WBC count, bacterial culture of sputum on admission . BDP inhalation therapy has little influence on respiratory bacterial infection at an asthmatic attack.

Oncol Res, 1997, 9(8), 411 - 7
In vivo antimetastatic action of ginseng protopanaxadiol saponins is based on their intestinal bacterial metabolites after oral administration; Wakabayashi C et al.; The present study demonstrated in vivo and in vitro antimetastatic activities of a major intestinal bacterial metabolite M1 formed from protopanaxadiol saponins of ginseng (the root of Panax ginseng C . A . Meyer) in comparison with its whole standardized extract and ginsenosides Rb1, Rb2, and Rc . Although Ginseng extract (1 mg/mouse) and ginsenosides (0.5 mg/mouse) significantly inhibited lung metastasis produced by i.v . injection of B16-BL6 melanoma cells in syngeneic mice (27-61% of untreated control), they hardly inhibited the invasion and migration of B16-BL6 melanoma and HT1080 fibrosarcoma cells in vitro . However, the intestinal bacterial metabolite M1 inhibited lung metastasis of melanoma cells and in vitro tumor cell invasion and migration at nontoxic or marginally toxic concentrations . Additionally, pharmacokinetic studies of ginsenoside Rb1 and M1 after oral administration (2 mg/mouse) revealed that intact Rb1 was not detectable in serum for 24 h by HPLC analysis, whereas the level of M1 in the serum reached maximum at 8 h (8.5 +/- 0.4 micrograms/ml) after Rb1 administration and at 2 h (10.3 +/- 1.0 micrograms/ml) after M1 administration . These findings suggest that the in vivo antimetastatic effect by oral administration of ginsenosides is mediated by their metabolic component M1.

Scand J Infect Dis, 1997, 29(5), 453 - 9
Increased prevalence of HIV-2 infection in hospitalized patients with severe bacterial diseases in Guinea-Bissau; Norrgren H et al.; We studied the association between HIV-2 infection and bacterial pneumonia, sepsis or pyomyositis, as well as the influence of HIV-2 infection on the clinical outcome in patients with these bacterial infections . A total of 201 consecutive hospitalized patients were included at the Simao Mendes National Hospital in Bissau, Guinea-Bissau . Age- and sex-matched controls were selected from an ongoing census in a semi-urban area of Bissau . Among 201 cases with such bacterial infection the prevalence of HIV-1 was 5.4%, HIV-2, 27.9%, and both HIV-1 and HIV-2 reactivity 6.4% . Among controls, the corresponding prevalence rates were significantly lower, 1.5%, 9.0% and 1.0%, respectively . A total of 140, 31 and 30 cases of pneumonia, sepsis and pyomyositis were included, and the differences in prevalence of HIV-2 compared with the controls also remained significant for each diagnosis separately . Lymphocyte subsets were determined in 93 consecutive patients, and the CD4 cell counts and CD4/CD8 lymphocyte ratios were markedly suppressed in the HIV-2-seropositive group . Due to excess mortality in the seropositive groups with sepsis (75.0%) and pyomyositis (25.0%), the mortality during hospitalization was significantly higher among HIV-2 infected compared to HIV-negative patients . Among cases of pneumonia the mortality was low in the HIV-2-seropositive (2.9%) as well as in the HIV-seronegative (3.4%) groupPIP: The association between HIV-2 infection and bacterial pneumonia, sepsis, and pyomyositis was examined in 201 consecutive patients hospitalized at Simao Mendes National Hospital in Bissau, Guinea-Bissau with such bacterial diseases and 201 age- and sex-matched controls drawn from a census in a semi-urban area of Bissau . Among cases, HIV-1 prevalence was 5.4%, HIV-2 prevalence was 27.9%, and combined HIV-1 and HIV-2 prevalence was 6.4% . Among controls, these prevalences were 1.5%, 9.0%, and 1.0%, respectively . The prevalence of HIV-2 infection was 25.0% among cases with pneumonia (n = 140), 38.7% among those with sepsis (n = 31), and 30.0% among those with pyomyositis (n = 30) . Among the 93 cases for whom T lymphocytes were determined, the absolute number and percentage of CD4 cells and the CD4/CD8 cell ratios were markedly suppressed in the HIV-2-positive group, especially in those with sepsis . Of the 194 patients available for follow-up, 160 were classified as cured or improved, 10 did not improve, and 24 died . Mortality from sepsis and pyomyositis was significantly greater among HIV-2-infected cases than HIV-negative patients . The median percentage of CD4 cells was significantly lower among HIV-2-positive patients who died (9.0%) than survivors (16.5%) . These findings confirm the existence of a significant association between HIV-2 and severe bacterial infections as well as a significantly higher mortality during hospitalization from sepsis and pyomyositis in HIV-2-positive patients compared to HIV-negative patients .

Nephron, 1997, 77(4), 479 - 81
Impaired bacterial killing and hydrogen peroxide production by polymorphonuclear neutrophils in end-stage renal failure; Porter CJ et al.; Polymorphonuclear leukocytes (PMN) isolated from a sub-population of patients with end-stage renal failure (ESRF) who were identified because they demonstrated impaired intracellular bacterial killing, were assayed for hydrogen peroxide activity using two different techniques capable of distinguishing between total and intracellular hydrogen peroxide generation . In an attempt to elucidate the mechanism of impaired intracellular bacterial killing further, hydrogen peroxide activity was compared to PMN isolated from patients receiving continuous ambulatory peritoneal dialysis and a control group of healthy normal volunteers . PMN from conservatively treated ESRF patients demonstrated reduced production of intracellular hydrogen peroxide (mean 37.7 +/- 4.3 fluorescence units), compared to PMN from both ESRF patients treated with continuous ambulatory peritoneal dialysis (mean 57.9 +/- 6.6 fluorescence units) and normal controls (mean 60.4 +/- 3.5 fluorescence units) . This suggests that the probable mechanism of impaired bacterial intracellular killing by the PMN of conservatively treated ESRF patients involves the production of intracellular hydrogen peroxide.

Eur J Biochem, 1997 Dec 1, 250(2), 524 - 31
Molybdate-uptake genes and molybdopterin-biosynthesis genes on a bacterial plasmid--characterization of MoeA as a filament-forming protein with adenosinetriphosphatase activity; Menendez C et al.; A gene cluster consisting of homologs to Escherichia coli moaA, moeA, moaC and moaE, which encode enzymes involved in the biosynthesis of molybdopterin cofactor (MoCo), and to modA, modB and modC, which encode a high-affinity molybdate transporter, were identified on pAO1 of Arthrobacter nicotinovorans near genes of molybdopterin-dependent enzymes involved in nicotine degradation . This gene arrangement suggests a coordinated expression of the MoCo-dependent and the MoCo-biosynthesis genes and shows that catabolic plasmids may carry the transport and biosynthetic machinery for the synthesis of the cofactors needed for the functioning of the enzymes they encode . pAO1 MoeA functionally complemented E . coli moeA mutants . The overexpressed and purified protein, of molecular mass 44,500 Da, associated into high-molecular-mass complexes and spontaneously formed gels at concentrations above 1 mg/ml . Transmission electron microscopy and atomic force microscopy revealed that MoeA forms fibrilar structures . In the presence of Mg2+ MoeA exhibited ATPase activity (0.020 pmol ATP x pmol protein(-1) x min(-1)) . ATP, ADP or AMP induced the disassembly of the MoeA fibers into aggregates . pAO1 MoeA shows 39% identity to the C-terminal domain of the rat neuroprotein gephyrin . Like gephyrin it binds to neurotubulin, but binds with preference to tubulin dimers.

Gene, 1997 Nov 20, 202(1-2), 203 - 8
Co-integration and expression of bacterial and genomic transgenes in the pancreatic and intestinal tissues of transgenic mice; Ali S et al.; Previous studies in the mammary gland have reported the 'rescue' of poorly expressed cDNA transgenes by their co-integration with a genomic sequence specifically expressed in the mammary tissue . To determine whether a highly expressed genomic sequence co-integrated with a cDNA sequence can rescue expression in other tissues, the expression of a bacterial gene, celE', encoding endoglucanase E' (EGE'), was investigated in the pancreatic and intestinal epithelia of transgenic mice . To rescue pancreatic expression, the human growth hormone genomic sequence was co-integrated with the bacterial gene, whereas to rescue intestinal expression, the genomic sequence encoding the intestinal fatty acid binding protein was used . In both studies the number of transgenics expressing celE' was significantly increased (60%) by the use of a genomic sequence, but only in the intestinal tissues was the level of celE' expression improved . However, this improvement was modest, representing at maximum only a doubling in the levels of EGE' . Thus permissive integration or rescue may be general, but the overall level of rescue is often insubstantial compared to the endogenous expression of the transgene genomic DNA.

Enferm Infecc Microbiol Clin, 1997 Oct, 15(8), 418 - 21
{Historical cohort study on bacterial pneumonias as predictors of the progression of the human immunodeficiency virus disease}; Teira R et al.; BACKGROUND: Recognition of the importance of bacterial pneumonias in the context of HIV infection has continuously grown throughout the pandemia . It has recently been suggested that these may be predictors of progression of the disease . PATIENTS AND METHODS: The evolution of an historic cohort of patients with HIV infection who were studied in 1989 with pneumonia regarding the presentation of AIDS or death was investigated . A control cohort was established, being age matched for sex, CD4 lymphocyte count, previous HIV disease and the use of zidovudine . Kaplan-Meier curves of survival without AIDS were made and compared by the logarythmic range test . Other predictors of progression were studied by the Cox models . RESULTS: Forty-nine patients were studied in each group, with a total of 121 and 153 patients/year of follow up . Final events were counted in 33 and 27 cases, respectively (p = 0.11) . The relative risk of progression was 1.55 (confidence interval of 95%, 0.93 to 2.56) for the group of pneumonias . The estimated relative risk (hazard) performed by a Cox model of proportional risks was however 1.85 (confidence interval of 95%: 1.05 to 3.25, p < 0.05) when the lymphocyte count adjustment was carried out according to the real values rather than by categories . CONCLUSIONS: The results of this historic cohort study support the existence of an association between history of bacterial pneumonia and the risk of HIV disease progression.

Infect Immun, 1998 Jan, 66(1), 343 - 6
Bacterial cytolysin perturbs round window membrane permeability barrier in vivo: possible cause of sensorineural hearing loss in acute otitis media; Engel F et al.; The passage of radioiodinated streptolysin-O (SLO) and albumin through the round window membrane (RWM) was studied in vivo . When applied to the middle ear, SLO became quantitatively entrapped in this compartment and no passage to the cochlea occurred . However, flux of radioiodinated albumin through the toxin-damaged RWM was observed . We propose that the passage of noxious macromolecules, such as proteases, from a purulent middle-ear effusion may be facilitated by pore-forming toxins, resulting in cochlear damage and sensorineural hearing loss.

Biochem J, 1997 Nov 15, 328 ( Pt 1), 145 - 51
N-terminal stretch Arg2, Arg3, Arg4 and Arg5 of human lactoferrin is essential for binding to heparin, bacterial lipopolysaccharide, human lysozyme and DNA; van Berkel PH et al.; Human lactoferrin (hLF), a protein involved in host defence against infection and excessive inflammation, interacts with heparin, the lipid A moiety of bacterial lipopolysaccharide, human lysozyme (hLZ) and DNA . To determine which region of the molecule is important in these interactions, solid-phase ligand binding assays were performed with hLF from human milk (natural hLF) and N-terminally deleted hLF variants . Iron-saturated and natural hLF bound equally well to heparin, lipid A, hLZ and DNA . Natural hLF lacking the first two N-terminal amino acids (Gly1-Arg2) showed reactivities of one-half, two-thirds, one-third and one-third towards heparin, lipid A, hLZ and DNA respectively compared with N-terminally intact hLF . A lack of the first three residues (Gly1-Arg2-Arg3) decreased binding to the same ligands to one-eighth, one-quarter, one-twentieth and one-seventeenth respectively . No binding occurred with a mutant lacking the first five residues (Gly1-Arg2-Arg3-Arg4-Arg5) . An anti-hLF monoclonal antibody (E11) that reacts to an N-lobe epitope including Arg5 completely blocked hLF-ligand interaction . These results show that the N-terminal stretch of four consecutive arginine residues, Arg2-Arg3-Arg4-Arg5, has a decisive role in the interaction of hLF with heparin, lipid A, hLZ and DNA . The role of limited N-terminal proteolysis of hLF in its anti-infective and anti-inflammatory properties is discussed.

Br J Obstet Gynaecol, 1997 Dec, 104(12), 1391 - 7
Impact of metronidazole therapy on preterm birth in women with bacterial vaginosis flora (Gardnerella vaginalis): a randomised, placebo controlled trial; McDonald HM et al.; OBJECTIVE: To ascertain whether metronidazole treatment of women with a heavy growth of Gardnerella vaginalis during mid-pregnancy would reduce the risk of spontaneous preterm birth . DESIGN: A multicentre, randomised, placebo-controlled trial . SETTING: Four metropolitan hospitals . PARTICIPANTS: Eight hundred and seventy-nine singleton women with a heavy growth of G . vaginalis or Gram stain indicative of bacterial vaginosis at 19 weeks of gestation . INTERVENTIONS: Oral metronidazole (400 mg) or placebo twice daily for two days at 24 weeks of gestation, and at 29 weeks if G . vaginalis found in test-of-cure swab four weeks after treatment . MAIN OUTCOME MEASURES: Spontaneous preterm birth less than 37 weeks . RESULTS: Intention-to-treat analysis showed no difference between metronidazole and placebo groups in overall preterm birth (31/429 {7.2%} vs 32/428 {7.5%}) or spontaneous preterm birth (20/429 {4.7%} vs 24/428 {5.6%}) . Among the 480 women with bacterial vaginosis treatment had no effect on spontaneous preterm birth (11/242 {4.5%} vs 15/238 {6.3%}) . In the subset of 46 women with a previous preterm birth, women in the metronidazole group showed a significant reduction in spontaneous preterm birth (2/22 {9.1%} vs 10/24 {41.7%}, OR 0.14, 95% CI 0.01-0.84) . A treatment effect was also found in compliant women with a previous preterm birth and bacterial vaginosis (0/14 {0%} vs 6/17 {35.3%}, OR 0.0, 95% CI 0.0-0.94) . CONCLUSION: Metronidazole treatment of women with a heavy growth of G . vaginalis or bacterial vaginosis did not reduce the preterm birth rate . Among women with a previous preterm birth, treatment reduced the risk of spontaneous preterm birth . Further studies are required to confirm these findings.

Br J Obstet Gynaecol, 1997 Dec, 104(12), 1398 - 404
Fetal fibronectin, endotoxin, bacterial vaginosis and cervical length as predictors of preterm birth and neonatal morbidity in twin pregnancies; Wennerholm UB et al.; OBJECTIVE: To evaluate the predictive values of fetal fibronectin, bacterial vaginosis, endotoxin and cervical length for preterm birth (< 35 and < 37 weeks) and neonatal morbidity in twin pregnancies . PARTICIPANTS: One-hundred and twenty-one women with twin pregnancies recruited into a prospective longitudinal study at three antenatal clinics in the southwest of Sweden . METHODS: Cervical or vaginal fluid was sampled and determined for fetal fibronectin (> or = 0.05 microgram/mL was used as cutoff), endotoxin (> or = 100 pg/mL) and bacterial vaginosis (presence of clue cells) at two week intervals from 24 to 34 weeks of gestation . The cervical length was measured with transvaginal sonography at the same time intervals . MAIN OUTCOME MEASURES: Occurrence of preterm birth (< 35 and < 37 weeks of gestation) and neonatal morbidity . RESULTS: All positive fetal fibronectin samples obtained at screening between 24 and 34 weeks predicted birth < 35 weeks (RR 18.0; 95% CI 2.2-145.9) . A positive fetal fibronectin at 28 weeks of gestation predicted delivery < 35 weeks (RR 6.3; 95% CI 2.6-15.1) with a sensitivity, specificity, positive and negative predictive value of 50.0, 92.0, 62.5 and 87.3%, respectively . An independent association between fetal fibronectin at 28 weeks and preterm birth (< 35 weeks) was verified with logistic regression (P = 0.03) . A positive fetal fibronectin at 28 weeks of gestation predicted neonatal morbidity (RR 5.1; 95% CI 2.4-11.0) and a longer period of care at the neonatal intensive care unit . The predictive power of cervical sonography was generally low but cervical length (cutoff < or = 33 mm) measured at 28 weeks of gestation was significantly associated with birth < 37 weeks (RR 2.2; 95% CI 1.1-4.2) . The presence of endotoxin correlated to bacterial vaginosis, but these tests were not significantly related to preterm birth or neonatal morbidity . CONCLUSIONS: Fetal fibronectin predicted preterm birth and neonatal morbidity in twin pregnancies . The predictive value of cervical length determinations was low . Endotoxin and bacterial vaginosis had no predictive power for preterm delivery in this study.

Microbiology, 1997 Dec, 143 ( Pt 12), 3671 - 82
Bacterial chemotaxis: Rhodobacter sphaeroides and Sinorhizobium meliloti--variations on a theme?
Armitage JP, Schmitt R.
We are only beginning to understand the mechanisms involved in tactic sensing in the alpha-subgroup of bacteria . It is clear, however, from recent developments that although the central chemosensory pathways are related to those identified in enteric species, the primary signals and the effect on flagellar behaviour are very different . The expression of chemoreceptors is under environmental control, and the strength of a response depends on the metabolic state of the cell . This is very different from enteric species which always respond to MCP-dependent chemoeffectors, and in which the expression of the receptors is constitutive . Chemotaxis in R . sphaeroides and S . meliloti is therefore more directly linked to the environment in which a cell finds itself . The integration of chemosensory pathways dependent on growth state may be much more suited to the fluctuating environment of these soil and water bacteria . There is still a great deal that needs to be understood about the mechanisms involved in motor control . The presence of at least two CheY homologues and the finding that the swimming speed of these bacteria can vary, and, in the case of S . meliloti, vary with chemosensory stimulation, suggests a different control mechanism at the flagellar motor where speed can be altered, or the motor stopped, with a full delta p still present . Why R . sphaeroides should have at least two functional sets of genes encoding homologues of the enteric chemosensory pathway remains to be determined . The major differences in sensory behaviour between the two alpha-subgroup species so far studied in detail and the differences from the enteric species suggests that many more variations of the chemosensory pathways will be found as more species are studied.

Shock, 1997 Dec, 8(6), 439 - 43
Role of peroxynitrite in the protein oxidation and apoptotic DNA fragmentation in vascular smooth muscle cells stimulated with bacterial lipopolysaccharide and interferon-gamma; O'Connor M et al.; In the present study, we investigated the role of endogenous and exogenous peroxynitrite in the process of DNA fragmentation and protein oxidation in cultured rat aortic smooth muscle cells . Peroxynitrite induced DNA fragmentation over a 24 hr period . The effect of peroxynitrite was unaffected by pretreatment with 3-aminobenzamide, an inhibitor of the nuclear enzyme poly (ADP-ribose) synthetase (PARS) . Stimulation of the smooth muscle cells with bacterial lipopolysaccharide and interferon-gamma produced nitric oxide and peroxynitrite, and resulted in a significant degree of apoptotic DNA fragmentation . The nitric oxide synthase inhibitor NG-methyl-L-arginine (3 mM), but not the PARS inhibitor 3-aminobenzamide (1 mM), reduced the DNA fragmentation . Stimulation with bacterial lipopolysaccharide and interferon-gamma also caused a marked oxidation of proteins in the smooth muscle cells, which was inhibited by NG-methyl-L-arginine, as well as by the superoxide dismutase mimetic Mn(III)tetrakis (4-benzoic acid) porphyrin . Based on these data, we propose a role for peroxynitrite-mediated, PARS-independent pathways in the apoptotic process and in the protein oxidation in bacterial lipopolysaccharide and interferon-gamma-stimulated smooth muscle cells.

J Infect Dis, 1998 Jan, 177(1), 102 - 6
Differences in N-acetylmuramyl-L-alanine amidase and lysozyme in serum and cerebrospinal fluid of patients with bacterial meningitis; Hoijer MA et al.; N-acetylmuramyl-L-alanine amidase (NAMLAA) specifically degrades peptidoglycan, a major component of bacterial cell walls . Lysozyme degrades peptidoglycan differently by hydrolyzing the aminosugar backbone of peptidoglycan . In another study, it was shown that the two enzymes act synergistically to inactivate the inflammatory properties of peptidoglycan . The presence of lysozyme and NAMLAA was determined in serum and cerebrospinal fluid (CSF) of patients with bacterial meningitis . High concentrations of lysozyme were found in CSF while, surprisingly, NAMLAA was not present . To explain this phenomenon, the degranulation pattern of neutrophils in CSF was compared with that of neutrophils from blood . Specific granules contain lysozyme and the azurophil granules contain both lysozyme and NAMLAA . CD66b expression on the cell surface, indicative for fusion of the specific granules with the cell membrane, was higher in CSF than in blood, while the marker for the azurophil granules was lower.

Pediatr Neurosurg, 1997 Mar, 26(3), 115 - 9
Spontaneous bacterial peritonitis in patients with ventriculoperitoneal shunts; Gaskill SJ et al.; Spontaneous bacterial peritonitis (SBP) is an infection of the peritoneal fluid in the absence of an obvious intra-abdominal source . It is most commonly diagnosed in patients with cirrhotic ascites, although it has been described in other syndromes as well . The organisms most frequently cultured from the peritoneum are those of intestinal flora; however, there are cases which have all the features of SBP, but remain culture negative . This article discusses 7 cases of SBP in patients with ventriculoperitoneal shunts; a combination which has previously not been described . The most significant features of these cases include: a remote history of shunt revision (mean 3.4 years), and cultures consistent with normal intestinal flora . None had a history of recent abdominal surgery, gastrostomy or wire-impregnated catheters . Cerebrospinal fluid cultures are often negative, and when positive, suggest SBP with an ascending shunt infection . While SBP is clearly differentiated from pseudocyst of the abdomen, it may represent a point on the continuum of intra-abdominal processes in the shunted patient . The precise etiology of SBP is unclear . A number of suggested theories are reviewed . It is proposed that patients with shunts may be predisposed to develop SBP because spinal fluid can behave as an ascitic fluid even in the absence of a peritoneal accumulation . Recommendations for the recognition and management of SBP in the shunted patient are discussed in detail.

Trends Biotechnol, 1997 Dec, 15(12), 500 - 6
Bacterial biosensors for monitoring toxic metals; Ramanathan S et al.; Biosensors utilize biological components to provide selectivity for monitoring compounds of environmental, clinical and industrial importance . A number of biosensors based on bacteria have recently been developed for monitoring toxic metals in the environment . The advantages and disadvantages of these types of biosensors are discussed.

Biol Reprod, 1997 Dec, 57(6), 1438 - 44
Interleukin (IL)-6 and IL-8 production by human amnion: regulation by cytokines, growth factors, glucocorticoids, phorbol esters, and bacterial lipopolysaccharide; Keelan JA et al.; Amniotic fluid at term contains high concentrations of interleukin (IL)-6 and IL-8 . The source of these cytokines has not been identified, although the fetal membranes (amnion and chorion) are likely contributors . Amnion cytokine production was investigated by using amnion cells isolated by enzymatic digestion (from placentas delivered at term before labor) and cultured in vitro . IL-6 and IL-8 were measured in conditioned media by ELISA . Amnion cells produced detectable amounts of both IL-6 and IL-8 throughout the 7-day culture period . The ratio of IL-8 to IL-6 was approximately 5:1, similar to the ratio found in amniotic fluid . Production of both IL-6 and IL-8 was stimulated in a concentration-dependent fashion by interleukin-1beta (0.1-10 ng/ml), tumor necrosis factor-alpha (1-100 ng/ml), and bacterial lipopolysaccharide (0.1-10 microg/ml), and also by 100 nM phorbol 12-myristate 13-acetate . Epidermal growth factor (1-25 ng/ml) had only minimal effects on amnion cytokine production . Dexamethasone (10 nM) inhibited IL-6/-8 production by approximately 50% throughout the culture period . Production of IL-6/-8 by cultured amniotic fibroblasts, which under basal conditions was much lower than that by epithelial cells, was regulated by all the agents tested in a fashion similar to that of the epithelial cells . These findings suggest that the amnion contributes to the pool of IL-6 and IL-8 in amniotic fluid . We speculate that amnion-derived cytokines might have functions during normal human parturition that are distinct from their conventional roles as inflammatory mediators.

Microbiol Mol Biol Rev, 1997 Dec, 61(4), 442 - 55
Rolling-circle replication of bacterial plasmids; Khan SA; Many bacterial plasmids replicate by a rolling-circle (RC) mechanism . Their replication properties have many similarities to as well as significant differences from those of single-stranded DNA (ssDNA) coliphages, which also replicate by an RC mechanism . Studies on a large number of RC plasmids have revealed that they fall into several families based on homology in their initiator proteins and leading-strand origins . The leading-strand origins contain distinct sequences that are required for binding and nicking by the Rep proteins . Leading-strand origins also contain domains that are required for the initiation and termination of replication . RC plasmids generate ssDNA intermediates during replication, since their lagging-strand synthesis does not usually initiate until the leading strand has been almost fully synthesized . The leading- and lagging-strand origins are distinct, and the displaced leading-strand DNA is converted to the double-stranded form by using solely the host proteins . The Rep proteins encoded by RC plasmids contain specific domains that are involved in their origin binding and nicking activities . The replication and copy number of RC plasmids, in general, are regulated at the level of synthesis of their Rep proteins, which are usually rate limiting for replication . Some RC Rep proteins are known to be inactivated after supporting one round of replication . A number of in vitro replication systems have been developed for RC plasmids and have provided insight into the mechanism of plasmid RC replication.

Am J Emerg Med, 1997 Nov, 15(7), 626 - 9
Measurement of synovial tumor necrosis factor-alpha in diagnosing emergency patients with bacterial arthritis; Jeng GW et al.; Because of the high morbidity and mortality in patients with bacterial arthritis, rapidly and correctly diagnosing this critical condition is a challenge to emergency clinicians . Synovial fluid samples were obtained from 75 patients with arthritis disorders who presented to an emergency service, and levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), and interleukin-6 (IL-6) were measured . Twenty patients with culture-proven bacterial arthritis had higher levels of synovial TNF-alpha than patients with osteoarthritis or with inflammatory arthritis, including gouty arthritis, rheumatoid arthritis, reactive arthritis, and lupus arthritis . There was a good sensitivity for synovial TNF-alpha level in diagnosing patients with bacterial arthritis . Nearly 100% of patients with bacterial arthritis had elevated synovial TNF-alpha levels . However, synovial IL-1 beta and IL-6 levels failed to discriminate bacterial arthritis from other inflammatory arthritis . Measurement of synovial TNF-alpha level may be useful as a diagnostic aid in emergency patients with bacterial arthritis disorders.

Biochemistry, 1997 Nov 18, 36(46), 14238 - 49
Proton and electron transfer to the secondary quinone (QB) in bacterial reaction centers: the effect of changing the electrostatics in the vicinity of QB by interchanging asp and glu at the L212 and L213 sites; Paddock ML et al.; The bacterial reaction center (RC) plays a central role in photosynthetic energy conversion by facilitating the light induced double reduction and protonation of a bound quinone molecule, QB . Two carboxylic acid residues, Asp-L213 and Glu-L212, located near QB, were previously shown to be important for proton transfer to QB . In this work, the ability of Glu to substitute for Asp at L213 and Asp to substitute for Glu at L212 was tested by site-directed mutagenesis . Both single mutants and a double mutant in which Asp and Glu were exchanged between the two sites were constructed . The electron transfer rate constants kBD (D+QAQB- --> DQAQB), and kAB(2) (DQA-QB- + H+ --> DQA(QBH)-), that are known to be sensitive to the energy of the QB- state, were found to be altered by Asp/Glu substitutions . Both rates were fastest ( approximately 10-fold) in RCs with Asp at both sites, slowest with Glu at both sites ( approximately 50-fold) and relatively unchanged by the caboxylic acid exchange . These changes could be explained if Asp was predominantly ionized and Glu was predominantly protonated at both sites (pH 7.5) . The charge recombination kBD suggests an observed approximately 5 pKa unit difference of Glu over Asp . Modeling of kBD by strong electrostatic interactions ( approximately 3-4 pKa units) among negatively charged acids and QB- indicated a lower intrinsic pKa for Asp compared to Glu at either site of approximately 2-3 units . The mechanism of the kAB(2) reaction was determined to be the same in all mutant RCs as for native RCs . A quantitative explanation of the effect of the electrostatic environment on kAB(2) was obtained using the two-step model proposed for native RCs {Graige, M . S., Paddock, M . L., Bruce, J . M., Feher, G., & Okamura, M . Y . (1996) J . Am . Chem . Soc . 118, 9005-9016} which involves fast protonation of the semiquinone followed by rate-limiting electron transfer . Using simple models for the quinone/quinol conversion rate, it is shown that the optimal electrostatic potential for the QB site is close to that found in native RCs.

J Biol Chem, 1997 Nov 21, 272(47), 29518 - 26
A mercuric ion uptake role for the integral inner membrane protein, MerC, involved in bacterial mercuric ion resistance; Sahlman L et al.; Bacterial detoxification of mercuric ion depends on the presence of one or more integral membrane proteins (MerT and/or MerC) whose postulated function is in transport of Hg2+ from a periplasmic Hg2+-binding protein (MerP) to cytoplasmic mercuric reductase . In this study, MerC from the Tn21-encoded mer operon was overexpressed and studied in vesicles and in purified form to clarify the role played by this protein in mercuric ion resistance . MerC-containing vesicles were found to take up mercuric ion independently of MerP . Since uptake correlated with the level of MerC expression was unaffected by osmotic pressure, and was only partially decreased in the presence of 0.05% Triton X-100, the observed uptake appears to represent mainly binding to MerC . Binding was inhibited by thiol-specific reagents, consistent with an essential role for cysteine residues . The essential thiol groups were inaccessible to hydrophilic thiol reagents, whereas hydrophobic reagents completely abolished Hg2+ binding . These observations are consistent with the predicted topology of the protein, wherein all 4 cysteine residues are either in the cytoplasm or the bilayer . A role for MerC in Hg2+ transport is thus also likely . Based on these results, a modified model for bacterial Hg2+ transport is proposed.

J Am Soc Nephrol, 1997 Dec, 8(12), 1971 - 6
Subacute bacterial endocarditis masquerading as type III essential mixed cryoglobulinemia; Agarwal A et al.; An adult man presented severely ill with vasculitis of his lower extremities and with impaired kidney function . After detailed evaluation at a local hospital, a diagnosis of essential type III cryoglobulinemia was made . High-dose steroid and cyclophosphamide therapy was begun . The patient improved dramatically . However, 6 wk later when his steroid dose was reduced to 30 mg daily, vasculitis recurred . Intensifying his immunosuppressive therapy only worsened his condition . He was than transferred to the Ohio State University Medical Center for consideration for plasmapheresis for the presumed essential type III cryoglobulinemia . However, our evaluation showed that he had bacterial endocarditis causing his type III cryoglobulinemia . When immunosuppressive drugs were stopped and antibiotics were begun, his condition resolved completely . This case illustrates the difficulty of identifying infectious causes of cryoglobulinemia and emphasizes that an initial, highly favorable response of vasculitis to immunosuppressive therapy does not exclude an infectious cause for the vasculitis.

Res Microbiol, 1997 Jan, 148(1), 11 - 20
Inhibition of bacterial cell surface extension by various means causes blocking of macromolecular synthesis; Lleo MM et al.; It has been suggested that, in rod-shaped bacteria, two sites for peptidoglycan assembly exist: one which is responsible for septum formation and the other, for lateral wall extension . The balance between the activities of these two sites enables bacteria to conserve their own morphology during cell growth . The effect of specifically inhibiting septum formation by different means (antibiotics and/or mutations), upon cell surface extension and macromolecular synthesis in rod-shaped and coccoid bacteria of various species, was studied . Inhibition of either cell wall expansion or macromolecular synthesis did not occur when septum formation was impaired in both rod-shaped bacteria and cocci possessing the two sites for peptidoglycan assembly, whereas a rapid and complete block of such synthesis was caused by inhibiting both sites in rod-shaped bacteria, or septum formation in cocci which possess only this site . These data indicate that bacteria possess a control mechanism that prevents macromolecular synthesis when envelope extension is inhibited.

Biol Trace Elem Res, 1997 Sep, 58(3), 255 - 61
Bioavailability of rumen bacterial selenium in mice using tissue uptake technique; Serra AB et al.; A tissue uptake experiment was conducted to determine the bioavailability of rumen bacterial Selenium (Se) in mice . The donor animal was wether fed a diet containing 0.2 mg Se/kg dietary dry matter (DM) . Ruminal fluid was collected 2 h postprandially . Bacterial-rich precipitate was obtained by differential centrifugation of the ruminal fluids . This was later freeze-dried and mixed in the diet to be used in feeding the mice experiment . Thirty growing female mice with a body wt (mean +/- SD) of 21.4 +/- 0.74 g were housed in plastic cages (5 mice/cage) and allotted equally to three dietary treatments . Diet 1 and Diet 2 were formulated based on AIN-76, except that no Se supplementation in the form of selenite was made in the former . In Diet 3, rumen bacterial matter was 20% of the diet, which gave an equivalent of 0.1 mg Se/kg dietary DM . The other two diets, Diet 1 and Diet 2, had an Se content of 0.025 and 0.1 mg/kg dietary DM, respectively . A 7-d feeding commenced after 7 d of acclimatization of the semipurified diet . Results showed that those mice fed an Se- (selenite) supplemented diet (Diet 2) had higher (P < 0.05) tissue Se concentrations than those mice fed the other two diets . No statistical differences were observed on various tissue Se concentrations between Diet 1 and Diet 3, although the latter diet had higher values . Kidney and liver had the highest Se concentrations compared to the other tissues . This study concludes that bacterial Se collected from the rumen of wether is not fully available for absorption in the intestine of the mice.

Trends Microbiol, 1997 Nov, 5(11), 454 - 8
Are bacterial exotoxins cytokine network regulators?
Henderson B, Wilson M, Wren B.
Bacterial exotoxins are generally thought to act by damaging cells or altering cell metabolism . However, recent work has established that many exotoxins modulate eukaryotic cell cytokine synthesis . Cytokine induction may play a significant role in exotoxin action, and therapeutic targeting of cytokines could be beneficial in infectious diseases involving bacterial exotoxins.

J Neurol, 1997 Oct, 244(10), 634 - 8
Level of transforming growth factor beta 1 is elevated in cerebrospinal fluid of children with acute bacterial meningitis; Huang CC et al.; We investigated the levels of transforming growth factor beta 1 (TGF-beta 1) in cerebrospinal fluid (CSF) in children with meningitis, with a view to prognostic relevance . CSF TGF-beta 1 levels on admission were measured by a sandwich enzyme immunoassay in children with bacterial meningitis (n = 16), aseptic meningitis (n = 12), and control subjects without evidence of central nervous system (CNS) infection (n = 16) . Patients were followed up for a mean duration of 13 months, and neurodevelopmental sequelae was determined for those with bacterial meningitis . On admission, CSF TGF-beta 1 levels were significantly higher in children with bacterial meningitis (mean, standard error, 32.92, 2.36 pg/ml) as opposed to those with aseptic meningitis (25.26, 1.72 pg/ml) (P = 0.0155), or control subjects (20.53, 1.05 pg/ml) (P < 0.0001) . The CSF TGF-beta 1 levels in children with aseptic meningitis were higher than those in the control group, but without significance (P = 0.02) . No apparent correlation existed between CSF TGF-beta 1 levels and CSF protein or cell counts in patients with bacterial meningitis . No significant difference in CSF TGF-beta 1 levels was found between patients with or without major sequelae following bacterial meningitis.

J Bacteriol, 1997 Dec, 179(24), 7869 - 71
Comparison of the bacterial HelA protein to the F508 region of the cystic fibrosis transmembrane regulator; Goldman BS et al.; The HelA protein of Rhodobacter capsulatus is the ATP-binding-cassette subunit of an exporter complex required for cytochrome c biogenesis . By primary sequence comparisons the F88 residue of HelA is similar to the F508 residue of the cystic fibrosis transmembrane regulator (CFTR) protein . Previous studies have established that CFTR F508delta or F508R proteins are defective but F508C is functional . Our results demonstrate that the HelA F88 mutants functionally mimic the phenotypes of known CFTR F508 mutants . The phenotypes of additional HelA mutants and the in vivo steady-state levels of these proteins are also reported.

J Leukoc Biol, 1997 Dec, 62(6), 859 - 64
Bacterial LPS and IFN-gamma trigger the tyrosine phosphorylation of vav in macrophages: evidence for involvement of the hck tyrosine kinase; English BK et al.; We and others have previously reported that tyrosine kinases play key roles in the activation of macrophages by both bacterial lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma) . However, little is known regarding the substrates of tyrosine phosphorylation that mediate macrophage activation and the resultant production of inflammatory mediators . In lymphocytes and other hematopoietic lineages, tyrosine phosphorylation of the proto-oncogene vav appears to be an essential component of cell activation . In this study, we demonstrate that both LPS and rIFN-gamma trigger the prompt, dose-dependent tyrosine phosphorylation of vav in murine RAW 264.7 macrophages . In addition, vav is physically associated with the src-related kinase hck in murine macrophages, and antisense oligonucleotides specific for murine hck block both LPS and rIFN-gamma-mediated vav phosphorylation . These findings suggest that hck probably mediates vav tyrosine phosphorylation during macrophage activation and that LPS and rIFN-gamma-mediated signaling pathways partially overlap.

J Prosthet Dent, 1997 Nov, 78(5), 518 - 21
Quantitative study of bacterial colonization of dental casts; Mitchell DL et al.; STATEMENT OF PROBLEM: Contamination of dental casts can occur if the record bases are improperly disinfected or inadvertently not disinfected during fabrication of a prosthesis . It is essential to develop an effective means of disinfecting dental casts from professional, medical, and legal points of view . PURPOSE: This study determined whether: (1) saliva contamination on the surface of the dental cast contributed to bacterial growth over time and (2) cleaning or disinfecting of dental casts can minimize bacterial growth . MATERIAL AND METHODS: Five dental casts were contaminated with saliva . Each cast was divided into six areas and swabbed at 15, 30, 60, 120, 180, and 240 minutes . Sheep blood agar plates were inoculated and incubated at 37 degrees C for 72 hours . Standardized dental stone cylinders were contaminated with 25 microliters of saliva and treated by rinsing in tap water, scrubbing with soap and tap water, soaking in 2% glutaraldehyde, or as controls with and without saliva contamination (n = 12) . The treated dental stone cylinders were placed in individual test tubes containing 2.5 ml of sterile phosphate-buffered solution and a final dilution of 10(-4) was achieved . Sheep blood agar plates were inoculated and incubated at 37 degrees C for 24 hours . RESULTS: Contamination of dental casts did not decrease, even when allowed to sit 4 hours before handling . Results also demonstrated that rinsing saliva-treated stone cylinders for 20 seconds significantly diminished bacterial contamination . Scrubbing with soap and tap water or soaking in 2% glutaraldehyde significantly reduced the bacterial contamination of saliva-treated stone cylinders when compared with rinsing with tap water . CONCLUSION: Bacterial contamination of dental casts can occur and requires an effective method of disinfecting.

Biochem Biophys Res Commun, 1997 Nov 26, 240(3), 629 - 34
Bacterial lipopolysaccharide induces early and late activation of protein kinase C in inflammatory macrophages by selective activation of PKC-epsilon; Shapira L et al.; Experiments from our and other laboratories have shown that specific inhibitors of protein kinase C (PKC) inhibited the secretion of nitric oxide, TNF alpha, and IL-1 beta from lipopolysaccharide (LPS)-stimulated macrophages, suggesting an important role for PKC in the inflammatory response . The present study was designed to investigate the mechanism whereby LPS stimulates PKC activity in inflammatory macrophages . Mouse macrophages were stimulated with 0-1 microgram/ml LPS for 0-18 hours, and PKC activity was detected in cell lysates . PKC isoform specificity was determined by blocking PKC activity with isoform-specific antibodies . Treatment of macrophages with 1 microgram/ml LPS induced a two-fold increase in PKC activity within 15 minutes and an additional more significant peak of PKC activity appeared 3 hours post-LPS stimulation . A lower dose of LPS (10 ng/ml) induced the later peak only . The enhancement in PKC activity induced by LPS occurred in both the cytosol and membrane fractions, but the enhancement in the membrane fraction was significantly greater than in the cytosol . The increase in PKC activity in both peaks was abolished only by the addition of anti-PKC-epsilon antibody . The present experiments suggest that PKC activation is an important pathway in the LPS-induced secretory response of macrophages and that PKC-epsilon is the major isoform involved.

J Theor Biol, 1997 Nov 7, 189(1), 107 - 19
Modelling Bacterial Degradation of Organic Compounds with Genetic Networks
Serra R, Villani M.
The bacterial degradation of organic compounds plays a crucial role in the biogeochemical cycles of the earth and in the clean-up of contaminated soils . The processes are carried out by bacterial consortia, rather than isolated strains, which are usually modelled by phenomenological kinetic equations which describe a fictitious, homogeneous bacterial species which mimics the behaviour of the consortium . An alternative modelling framework is presented here, where the bacterial consortia are considered as networks of genes interacting with other genes as well as with chemicals, which may be either introduced from outside or produced by bacterial metabolism . The model is based on an extension of the random Boolean network model of genetic networks, which makes use of continuous dynamical variables . Three different models are introduced, which differ in the way how they account for the existence of different species: (i) a single supercell model, where all the genes can interact strongly with each other; (ii) a graded interaction model, where genes interact strongly within a species, and weakly among different species; and (iii) a separate subsets model, where genes interact only within species . It is shown how this modelling framework is sound, as it is able to reproduce some of the generic behaviours of bacterial consortia, describing experimentally observed phenomena like population changes induced by contamination, and prey-predator dynamics.

Proc Natl Acad Sci U S A, 1997 Nov 25, 94(24), 12833 - 8
Isolation and bacterial expression of a sesquiterpene synthase cDNA clone from peppermint (Mentha x piperita, L.) that produces the aphid alarm pheromone (E)-beta-farnesene; Crock J et al.; (E)-beta-Farnesene is a sesquiterpene semiochemical that is used extensively by both plants and insects for communication . This acyclic olefin is found in the essential oil of peppermint (Mentha x piperita) and can be synthesized from farnesyl diphosphate by a cell-free extract of peppermint secretory gland cells . A cDNA from peppermint encoding (E)-beta-farnesene synthase was cloned by random sequencing of an oil gland library and was expressed in Escherichia coli . The corresponding synthase has a deduced size of 63.8 kDa and requires a divalent cation for catalysis (Km for Mg2+ approximately 150 microM; Km for Mn2+ approximately 7 microM) . The sesquiterpenoids produced by the recombinant enzyme, as determined by radio-GC and GC-MS, are (E)-beta-farnesene (85%), (Z)-beta-farnesene (8%), and delta-cadinene (5%) with the native C15 substrate farnesyl diphosphate (Km approximately 0.6 microM; Vrel = 100) and Mg2+ as cofactor, and (E)-beta-farnesene (98%) and (Z)-beta-farnesene (2%) with Mn2+ as cofactor (Vrel = 80) . With the C10 analog, GDP, as substrate (Km = 1.5 microM; Vrel = 3 with Mg2+ as cofactor), the monoterpenes limonene (48%), terpinolene (15%), and myrcene (15%) are produced.

Eur J Clin Invest, 1997 Nov, 27(11), 936 - 42
The role of intravenous administration of dextran 70 in enteric bacterial translocation after partial hepatectomy in rats; Wang XO et al.; The aim of this study was to assess the effect of intravenous dextran on bacterial translocation and intestinal vascular endothelial and epithelial barrier function after experimental partial hepatectomy . We determined systemic arterial pressure, enteric bacterial growth (proximal and distal small intestine and colon) and bacterial translocation (BT) to mesenteric lymph nodes (MLN), liver, lungs, spleen, kidneys and blood, as well as intestinal vascular endothelial and epithelial barrier permeability, after sham operation or partial hepatectomy (50% and 90%) with preoperative intravenous administration of saline, albumin or dextran 70 . Subtotal hepatectomy induced a significant decrease in arterial pressure and an increase in the number of Escherichia coli in the distal small intestine . BT was not observed in sham-operated animals or in rats with 50% hepatectomy administered dextran . The number of positive cultures of enteric bacteria was significantly increased after hepatectomy, whereas dextran treatment decreased the number of animals with BT . Increased permeability of the intestinal vascular endothelial and epithelial barriers was noted in hepatectomized animals, while dextran prevented hepatectomy-induced vascular endothelial barrier injury . Enteric bacterial translocation occurred following partial hepatectomy in the rat, associated with bacterial overgrowth in the distal small intestine . Intravenous administration of dextran 70 prevented bacterial overgrowth and translocation, at least in part, by maintaining gut vascular endothelial barrier integrity

Eur J Clin Invest, 1997 Nov, 27(11), 885 - 92
Helicobacter pylori and non-Helicobacter pylori bacterial flora in gastric mucosal and tumour specimens of patients with primary gastric lymphoma; Jonkers D et al.; There is an association between Helicobacter pylori (H . pylori) and gastric mucosa-associated lymphoid tissue (MALT) and MALT lymphoma . Histologically, mainly non-specific stains are used to detect H . pylori, such as haematoxylin-eosin (HE) or modified Giemsa (MG) . In this study, both a MG and a specific immunohistochemical stain (IMM) for H . pylori (Dako B471) were performed on sequential slides of resected material containing tumour and non-tumorous gastric mucosa from patients with primary gastric lymphoma (n = 52) . Special attention was paid to the presence of non-H . pylori bacterial flora diagnosed by a positive MG (according to form and localization) and a subsequently negative IMM . On all slides, bacterial density was scored semiquantitatively (grades 0, 1, 2, 3) . In total, 32 (61.5%) patients were H . pylori positive using IMM and 34 (65.4%) were non-H . pylori positive using MG . In 24 out of the 34 patients, the non-H . pylori flora consisted mainly of cocci in combination with rods in 15 patients, mostly in minor quantities; in another 10 patients, high numbers of both cocci and different types of rods were present . Most non-H . pylori bacteria were localized superficially, although in 22 patients minor quantities of non-H . pylori were also seen in the glandular lumina . After all of the patients had been analysed, no differences in the density of H . pylori and of non-H . pylori flora were found . Only when comparing patients who had a small-cell lymphoma with those who had a large-cell lymphoma was a significantly higher density of H . pylori found in the corpus mucosa of large-cell lymphomas and a higher prevalence of non-H . pylori was found in tumours, in antrum or corpus, of patients with large-cell lymphomas . In conclusion, with joint evaluation using MG and a H . pylori-specific immunohistochemical stains, the proportion of H . pylori-positive gastric lymphoma patients was lower than in most previous studies but other bacteria were found in a relatively high proportion . The role of the non-H . pylori intragastric bacterial flora identified in this study has to be further elucidated in the aetiopathogenesis of primary gastric lymphoma.

Gastroenterology, 1997 Dec, 113(6), 1848 - 57
Murine CD4 T-cell response to Helicobacter infection: TH1 cells enhance gastritis and TH2 cells reduce bacterial load; Mohammadi M et al.; BACKGROUND & AIMS: Previous findings suggest that TH1 cellular immune responses contribute to Helicobacter-associated gastritis . To further investigate this issue, interleukin 4 gene targeted mice were infected with Helicobacter felis, and a series of adoptive transfer experiments was performed to evaluate the role of both TH1 and TH2 cells . METHODS: Antigen-specific spleen cells from immunized/challenged or nonimmunized/infected mice or CD4+ T-cell lines were transferred adoptively into naive recipients before live bacterial challenge . RESULTS: Transfer of cells from both groups of donors as well as TH1 or TH2 cell lines exacerbated gastric inflammation in the recipients . No effect on bacterial load was observed in recipients of bulk spleen cells from infected mice or recipients of TH1 cell lines . In contrast, when either a TH2 cell line or bulk cells from immunized challenged mice were transferred adoptively, recipients showed a dramatic reduction in bacterial load . Increased numbers of bacteria were also noted in interleukin 4-deficient mice . CONCLUSIONS: These data suggest a differential contribution of TH1 and TH2 cell-mediated immune responses in Helicobacter infection: one associated with the pathogenesis of disease (TH1 phenotype) and the other associated with protection from or control of infection (TH2 phenotype).

J Cereb Blood Flow Metab, 1997 Nov, 17(11), 1221 - 9
Heparin inhibits leukocyte rolling in pial vessels and attenuates inflammatory changes in a rat model of experimental bacterial meningitis; Weber JR et al.; Heparin is a natural proteoglycan that was first described in 1916 . In addition to its well characterized effect on blood coagulation, it is becoming clear that heparin also modulates inflammatory processes on several levels, including the interference with leukocyte-endothelium interaction . Anecdotal observations suggest a better clinical outcome of heparin-treated patients with bacterial meningitis . The authors demonstrate that heparin, a glycosaminoglycan, inhibits significantly in the early phase of experimental pneumococcal meningitis the increase of 1) regional cerebral blood flow (125 +/- 18 versus 247 +/- 42%), 2) intracranial pressure (4.5 +/- 2.0 versus 12.1 +/- 2.2 mm Hg), 3) brain edema (brain water content: 78.23 +/- 0.33 versus 79.49 +/- 0.46%), and 4) influx of leukocytes (571 +/- 397 versus 2400 +/- 875 cells/microL) to the cerebrospinal fluid compared with untreated rats . To elucidate the possible mechanism of this observation, the authors investigated for the first time leukocyte rolling in an inflammatory model in brain venules by confocal laser scanning microscopy in vivo . Heparin significantly attenuates leukocyte rolling at 2, 3, and 4 hours (2.8 +/- 1.3 versus 7.9 +/- 3.2/100 microm/min), as well as leukocyte sticking at 4 hours (2.1 +/- 0.4 versus 3.5 +/- 1.0/100 microm/min) after meningitis induction compared with untreated animals . The authors conclude that heparin can modulate acute central nervous system inflammation and, in particular, leukocyte-endothelium interaction, a key process in the cascade of injury in bacterial meningitis . They propose to evaluate further the potential of heparin in central nervous system inflammation in basic and clinical studies.

J Acquir Immune Defic Syndr Hum Retrovirol, 1997 Nov 1, 16(3), 169 - 75
Are HTLV-II-seropositive injection drug users at increased risk of bacterial pneumonia, abscess, and lymphadenopathy?
Modahl LE, Young KC, Varney KF, Khayam-Bashi H, Murphy EL.
Disease associations of HTLV-II are poorly defined, despite a high seroprevalence among injection drug users (IDU) . One hundred twenty-four HTLV-II-seropositive emergency room and clinic patients were matched by age, sex, and clinic to 120 HTLV-I/II-seronegative patients . Medical records were reviewed blinded to HTLV-II status, and International Classification of Disease 9th Clinical Modification (ICD-9CM)-coded diagnoses were compared between seropositive patients and controls . After adjustment for relevant confounding variables such as human immunodeficiency virus infection, HTLV-II-seropositive IDU had an increased risk of bacterial pneumonia (odds ratio {OR}, 3.45; 95% confidence interval {CI}, 1.58, 7.56), abscess (OR, 8.30; 95% CI, 4.02, 17.11), and lymphadenopathy (OR, 3.91; 95% CI, 1.24, 12.32) compared with HTLV-II-negative non-IDU patients . In contrast, HTLV-II-negative IDU were at only marginally increased risk of the same conditions, with OR of 1.76 (95% CI, 0.42, 7.40), 3.00 (95% CI, 0.94, 9.59), and 1.31 (95% CI, 0.15, 11.66), respectively . These results indicate that HTLV-II seropositivity may define a subgroup of IDU who are at particularly high risk of bacterial pneumonia, skin and soft tissue abscess, and lymphadenopathy . Whether HTLV-II has an etiologic role in predisposing IDU to bacterial infections and lymphadenopathy will require further investigation.

J Trauma, 1997 Nov, 43(5), 852 - 5
Splanchnic ischemia and bacterial translocation in the abdominal compartment syndrome; Diebel LN et al.; BACKGROUND AND METHODS: Major trauma or abdominal injury may lead to the development of increased intra-abdominal pressure (IAP) and the onset of the abdominal compartment syndrome . Although the effect of raised IAP on systemic and splanchnic hemodynamics have been described, the consequences of the resultant gut hypoperfusion in this setting are unknown . Bacterial translocation (BT) occurs after a period of splanchnic ischemia and may contribute to later organ failure . A rodent model was used to examine the effect of raised IAP on ileal mucosal blood flow (MBF) and BT . IAP was increased to 25 mm Hg for 60 minutes and mean arterial blood pressure was maintained with fluid . Animals were killed 24 hours later and examined for BT . RESULTS: Increased IAP resulted in a decrease of MBF to 63% of baseline despite maintaining normal mean arterial blood pressure . BT occurred principally to the mesenteric lymph nodes after 60 minutes of IAP at 25 mm Hg . CONCLUSIONS: Increased IAP leads to decreased MBF and to BT, which may contribute to later septic complications and organ failure.

J Trauma, 1997 Nov, 43(5), 759 - 63
Secretory immunoglobulin A blocks hypoxia-augmented bacterial passage across Madin-Darby canine kidney cell monolayers; Diebel LN et al.; OBJECTIVE: To study the relative impact of previous hypoxic exposure and the addition of secretory immunoglobulin A (IgA) on bacterial translocation . DESIGN: In vitro randomized experimental study . MATERIALS AND METHODS: Transfected Madin-Darby canine kidney epithelial cells were grown as monolayers in a two-chamber tissue culture system . Stationary growth phase Escherichia coli M14 were inoculated in the apical chamber with medium or medium containing polymeric secretory IgA . Tissue culture dishes were then placed in a 21 or 5% O2 incubator environment for 90 minutes followed by a 21% O2 environment . Medium from the basal compartment was then obtained at timed intervals for bacterial culture . MEASUREMENT AND MAIN RESULTS: Bacterial translocation increased with time in co-culture . Previous hypoxic exposure augmented translocation across the monolayers . The addition of IgA blocked translocation under both normoxic and hypoxic conditions . CONCLUSION: Secretory IgA is important in mucosal defense under both normal and shock conditions.

Arch Biochem Biophys, 1997 Dec 1, 348(1), 157 - 62
The role of cysteinyl residues in the activity of bacterial elongation factor Ts, a guanosine nucleotide dissociation protein; Hwang YW et al.; The modification of E.coli elongation factor Ts (EF-Ts) by NEM and other sulfhydryl reagents inactivates the protein's ability to bind EF-Tu.GDP and to catalyze GDP exchange . The reactive residue was found to be Cys-22 . Replacement of Cys-22 by Ser or Gly only partially impairs the binding or catalytic properties of EF-Ts while it completely protects EF-Ts from the inactivation by NEM . Cys-22 of EF-Ts is not located at the EF-Ts.EF-Tu interface, yet it can be modified only when EF-Ts is not bound to EF-Tu . These results support the proposal that the conformation change around Cys-22 in the amino terminus of EF-Ts rather than Cys-22 itself is essential for binding EF-Tu . Apparently, modification of Cys-22 by NEM disrupts the conformation change and inactivates EF-Ts . The return of EF-Ts to its native conformation may provide the driving force for the rate-determining step in the catalytic cycle, the dissociation of EF-Ts from EF-Tu.GNP.

J Clin Pathol, 1997 Sep, 50(9), 790 - 1
Screening for bacterial vaginosis: a novel application of artificial nose technology; Chandiok S et al.; The AromaScan system was used to analyse vaginal swabs from 68 women attending a genitourinary clinic . Using clinical criteria, subjects were assessed for bacterial vaginosis . After training the AromaScan system to recognise patterns generated from four patients with and four patients without bacterial vaginosis, 16 of the 17 (94%) remaining subjects were correctly identified as having the condition . The positive predictive value of the test was 61.5% . These results indicate that the AromaScan technology may be of value as a screening test for bacterial vaginosis.

Genitourin Med, 1997 Aug, 73(4), 306 - 7
When is bacterial vaginosis not bacterial vaginosis?--a case of cervical carcinoma presenting as recurrent vaginal anaerobic infection; Hudson MM et al.; Vaginal anaerobic infection is the most common cause of vaginal discharge in women . We present a case of recurrent vaginal anaerobic infection and cervical carcinoma and discuss the association of the two conditions . More frequent cytology/colposcopy may be indicated in women who give a history of recurrent or persistent vaginal anaerobic infection.

Genitourin Med, 1997 Aug, 73(4), 267 - 70
Treatment of male partners and recurrence of bacterial vaginosis: a randomised trial; Colli E et al.; OBJECTIVE: To test the efficacy of treatment with clindamycin of a partner on the recurrence rate of bacterial vaginosis in women within 3 months from diagnosis . SUBJECTS: Eligible for the study were sexually active women with one current sexual partner, who were aged 18-45 years, with a clinical diagnosis of bacterial vaginosis and whose partner agreed to be treated . METHODS: A double blind, randomised, controlled trial was conducted comparing the effect of treating the partner with either clindamycin capsules or placebo on the reduction of the recurrence rate of bacterial vaginosis . Women were treated with clindamycin 2% vaginal cream, administered intravaginally once daily at bedtime for 7 consecutive days . The partners were randomly allocated to clindamycin hydrochloride capsules, 150 g by mouth four times daily for 7 consecutive days, or a placebo . A total of 139 couples were randomised--69 were treated with clindamycin vaginal cream group and 70 with placebo . One, 4, and 12 weeks after the end of treatment the patients and their partners were examined; vaginal discharges were examined to check for clue cells, vaginal pH was determined, and a KOH test carried out . RESULTS: Overall, 131 women out of the 139 who entered the study were cured (94.2%, lower 95% confidence interval 79.8, based on Poisson's approximation) . There was no difference in the cure rate among women whose partner received clindamycin or placebo (chi(2) p = not significant) . A total of 55 couples (26 in the clindamycin and 29 in the placebo group) withdrew from the study during the follow up period . Of the 69 women whose partner received clindamycin, 22 (31.9%) reported "recurrence" or persistence . The corresponding number was 21 (30%) of the 70 women whose partner received placebo (chi(2) p = not significant) . Of the 84 couples in which the woman was cured by the first week's visit and who completed the study; there were five recurrences (11.6%) among the 43 women whose partner received clindamycin and nine (22.0%) of the 41 whose partner received placebo (chi(2) p = not significant) . CONCLUSION: This study indicates that vaginal clindamycin is effective and safe in the treatment of bacterial vaginosis, but it does not support the suggestion that male treatment markedly reduces the short term recurrence rate.

Hua Xi Yi Ke Da Xue Xue Bao, 1996 Dec, 27(4), 418 - 21
{Rhubarb decoction prevents intestinal bacterial translocation during necrotic pancreatitis}; Chen X et al.; This is a study on the efficacy and mechanism of rhubarb therapy for necrotizing pancreatitis in rats induce by intraductal infusion of 2% deoxycholate 0.4 ml/kg . The rats with such pancreatitis were orally fed with 10% rhubarb decoction 1.5 ml (treatment group n = 8) or normal saline 1.5 ml (control group n = 9) per 8 hours . Sham operated rats (sham group n = 8) were given intraductal infusion of normal saline 0.4 ml/kg . 48 hours after infusion, the rats were killed for studies of intestinal motility, serum endotoxin and amylase levels as well as bacterial cultures in messentary lymph nodes (MLN) and pancreas tissues . 5 rats died in the control group (5/9) and 1 died in the treatment group (1/8) . Remarkable inhibition of gut motility was observed in control group, but gut motility was significantly improved by administration of rhubarb in treatment group . No rat died in the sham group and the rate therein were all free from endotoxemia or positive cultures . Endotoxin level of control group is much higher (61.36 +/- 28.30 pg/L) than that of treatment group (5.41 +/- 3.58 pg/L), (P < 0.001) . Positive cultures were noted in most of MLN (4/4) and pancreas (4/4) in control group, but only 1 in MLN and 1 in pancreas were noted in treatment group . It is concluded that in the treatment of necrotic pancreatitis in rats rhubarb decoction is effective for promoting gut motility and preventing intestinal bacterial translocation.

Acta Ophthalmol Scand, 1997 Aug, 75(4), 466 - 9
Metastatic bacterial endophthalmitis . A report of four cases all leading to blindness; Piczenik Y et al.; PURPOSE: To draw attention to the rare but severe entity of endophthalmitis as encountered due to metastatic spread of bacteria . METHODS: We report our experience from four cases of metastatic bacterial endophthalmitis . RESULTS: Systemic infection (Pneumococcus meningitis) was evident in two cases, but in the other two there was no early clue to systemic infection . Eventually, however, endocardial vegetations were disclosed as the source of bacterial emboli (E.coli, peptostreptococcus) . In the most atypical patient, magnetic resonance scanning had indicated disseminated brain tumours, and only autopsy revealed the infectious nature of the disease . Ocular ultrasonography being part of the work-up, the four eyes under study all showed marked morphological intraocular changes, including 'solid tumour' in the presumed neoplastic case . CONCLUSION: Our cases stress the severity of metastatic bacterial endophthalmitis and the easily missed early diagnosis, even where experienced clinicians are involved . The role of diagnostic ultrasound is discussed.

Transplantation, 1997 Nov 15, 64(9), 1370 - 3
Influence of bacterial endotoxin on radiation-induced activation of human endothelial cells in vitro and in vivo: interleukin-10 protects against transendothelial migration; Lindner H et al.; To extend previous studies on the anti-inflammatory role of interleukin (IL)-10 in vivo, mice pretreated with IL-10 were subjected to ionizing radiation (IR), lipopolysaccharide (LPS), or both and assessed for the expression of the intercellular adhesion molecule 1 (ICAM-1) in immunohistochemical analyses . IL-10 was able to almost fully protect LPS+IR-treated animals against ICAM-1 up-regulation . Because LPS and IR also increased adhesion of peripheral blood mononuclear cells, transendothelial migration assays were performed to investigate the functional significance of these findings . IR was found to induce transendothelial migration, and this effect could be enhanced by cotreatment with LPS, in the same fashion as peripheral blood mononuclear cell adhesion . Also in this system, IL-10 proved to act as a potent LPS antagonist . Finally, in vivo immunohistochemical analyses revealed an infiltration of CD3+ T lymphocytes into organs that were the target of transplant-related complications after LPS+IR treatment . This infiltration could also be completely reversed by IL-10 pretreatment.

J Bacteriol, 1997 Nov, 179(22), 6971 - 8
hetC, a gene coding for a protein similar to bacterial ABC protein exporters, is involved in early regulation of heterocyst differentiation in Anabaena sp . strain PCC 7120; Khudyakov I et al.; Transposon-generated mutant C3 of Anabaena sp . strain PCC 7120 is unable to form heterocysts upon deprivation of combined nitrogen but forms a pattern of spaced, weakly fluorescent cells after 2 days of deprivation . Sequence analysis of chromosomal DNA adjacent to the ends of transposon Tn5-1058 in mutant C3 showed a 1,044-amino-acid open reading frame, designated hetC, whose predicted protein product throughout its C-terminal two-thirds has extensive similarity to the HlyB family of bacterial protein exporters . Its N-terminal third is unique and does not resemble any known protein . hetC lies 1,165 bp 5' from the previously described gene hetP . Reconstruction of the C3 mutation and its complementation in trans with a wild-type copy of hetC confirmed that hetC has an essential regulatory role early in heterocyst development . hetC is induced ca . 4 h after nitrogen stepdown, hours after induction of hetR . Expression of hetC depends on HetR and may depend on HetC . Highly similar sequences are present 5' from the initiation codons and in the 3' untranslated regions of hetC and of two heterocyst-specific genes, devA and hetP.

J Reprod Fertil, 1997 Sep, 111(1), 135 - 41
Inhibition of bacterial and boar epididymal sperm immunogenicity by boar seminal immunosuppressive component in mice; Dostal J et al.; Intravenous deposition of the immunosuppressive component, isolated from boar seminal vesicle secretion, led to suppression of primary and secondary antibody response to boar epididymal spermatozoa and to bacterial antigens . The most effective suppression of the immune response was achieved in female mice treated with immunosuppressive component 3 days before the immunization with antigen . The treatment with immunosuppressor 3 days after the immunization resulted in less effective immunosuppression . After the primary immunization, male mice displayed low sensitivity to epididymal spermatozoa . The production of IgG and IgM antibodies to spermatozoa was depressed for a relatively long period in female mice treated with immunosuppressor . The immunosuppressive components of the reproductive gland secretions may protect sperm cells from the adverse effect of the immune system cells and enhance the chance of conception . However, seminal immunosuppressive components may play an unfavourable role by producing a predisposition in the reproductive tract to bacterial or viral infections.

Eur J Biochem, 1997 Oct 15, 249(2), 383 - 92
Different consequences of incorporating chloroplast ribosomal proteins L12 and S18 into the bacterial ribosomes of Escherichia coli; Weglohner W et al.; We have incorporated chloroplast ribosomal proteins (R-proteins) L12 and S18 into Escherichia coli ribosomes and examined the hybrid ribosomes for their ability to form polysomes in vivo and perform poly(U)-dependent poly(Phe) synthesis in vitro . The rye chloroplast S18 used for the experiment is a highly divergent protein (170 amino acid residues; E . coil S18, 74 residues), containing a repeating, chloroplast-specific, heptapeptide motif, and has amino acid sequence identity of only 35% to E . coli S18 . When expressed in E . coli, chloroplast S18 was assembled in E . coli ribosomes . The latter formed polysomes in vivo at about the same rate as the host ribosomes, indicating that the replacement of E . coli S18 with its chloroplast homologue has only a minor, if any, effect on function . The L12 protein is much more conserved in sequence and chain length, and is known to have a very important function . The Arabidopsis chloroplast L12 used in the experiment was incorporated into E . coli 50S subunits that associated with the 30S subunits to form ribosomes, but the latter were unable to form polysomes . This result indicates functional inactivation of E . coil ribosomes by a chloroplast R-protein . To further confirm this result, we overproduced chloroplast L12 through the use of a secretion vector and purified the protein to homogeneity . Chloroplast L12 could be efficiently incorporated in vitro into L7/12-lacking E . coli ribosomes, but the hybrid ribosomes were totally inactive in poly(U)-dependent poly(Phe) synthesis . Computer modeling of the spatial structure of all known chloroplast L12 proteins (using E . coli L12 coordinates) indicated a 'chloroplast loop' present only in chloroplast L12 . The presence of this loop might have a role in the observed inactivation . Taken together with previously reported results (summarized in this paper), it would appear that the features of chloroplast R-proteins concerned with specific functions are more divergent than their assembly properties . We have previously described methods suitable for overproduction and purification of chloroplast R-proteins that are encoded in organellar DNA (approximately 20), but that gave poor yield for those encoded in the nuclear DNA (approximately 45) . Here we describe a method that overcomes this problem and allows the purification of nucleus-encoded chloroplast R-proteins in milligram quantities.

Trends Biotechnol, 1997 Nov, 15(11), 458 - 64
Bacterial N-acyl-homoserine-lactone-dependent signalling and its potential biotechnological applications; Robson ND et al.; N-acyl homoserine lactones are bacterial signalling molecules involved in regulating diverse metabolic functions, particularly those relating to virulence, in concert with cell density . Each aspect of the signalling pathway, from production and recognition of the signal to expression of the target genes, offers a potential opportunity for exploitation . Attention is now focusing on the development of novel methods for bacterial enumeration, modulation of bacterial virulence and flexible, coordinated expression of heterologous genes through the use of N-acyl-homoserine-lactone-based systems.

Vet Clin North Am Food Anim Pract, 1997 Nov, 13(3), 483 - 93
Bacterial pneumonia; Mosier DA; Bacteria play a critical role in the severe pneumonia and fatalities associated with the bovine respiratory disease complex . Although numerous bacteria have the potential to cause pneumonia, only a small number of these are responsible for the majority of cases of disease . Virulence and immunogenic characteristics of these organisms are important determinants of the host response to infection . These bacterial characteristics are reviewed and applied to a discussion of the epidemiology, pathogenesis, and prevention of bacterial pneumonia is also discussed.

Arch Surg, 1997 Nov, 132(11), 1190 - 5
Bacterial translocation is inhibited in inducible nitric oxide synthase knockout mice after endotoxin challenge but not in a model of bacterial overgrowth; Mishima S et al.; BACKGROUND: Studies have shown that nitric oxide (NO) and NO synthase (NOS) inhibitors injure and protect organs after endotoxin (lipopolysaccharide {LPS}) challenge . OBJECTIVE: To test the hypothesis that LPS-induced gut injury and bacterial translocation (BT) are mediated through activation of inducible NOS (iNOS) . DESIGN: A randomized, controlled study using genetically altered, iNOS gene knockout mice . SETTING: University research laboratory . METHODS: Forty-five wild-type (iNOS+/+) or homozygous mutant (iNOS-/-) mice weighing 25 to 35 g were challenged with Escherichia coli LPS or saline (10 mg/ kg) intraperitoneally (n = 8/group) . In a second set of experiments, a bacterial overgrowth model of BT (E coli monoassociation) was tested (n = 6-7/group) . The mesenteric lymph nodes and cecums were cultured, and liver, ileal, and blood nitrite and nitrate levels measured 24 hours after LPS or E coli monoassociation . RESULTS: After LPS challenge, 87.5% of the iNOS+/+ mice but 0% of the iNOS-/- mice had BT to their mesenteric lymph nodes (P < .01; chi 2 analysis) . Nitrite and nitrate levels of the liver, ileum, and blood were higher in the iNOS+/+ mice (P < .05) . In the E coli overgrowth model, BT to mesenteric lymph nodes occurred in 100% of iNOS-/- and iNOS+/+ mice . CONCLUSIONS: In this limited study, LPS-induced BT did not occur in iNOS-deficient mice, suggesting that LPS induction of increased iNOS activity is necessary for LPS-induced BT to occur . In contrast, iNOS activation does not seem to be necessary in a bacterial overgrowth model of BT.

Carcinogenesis, 1997 Oct, 18(10), 1883 - 8
Bacterial and mammalian DNA alkyltransferases sensitize Escherichia coli to the lethal and mutagenic effects of dibromoalkanes; Abril N et al.; Here we confirm and extend our previous studies demonstrating that the mutagenic potency of 1,2-dibromoethane (DBE) and dibromomethane (DBM) is markedly enhanced (not prevented) in bacteria expressing the O6-alkylguanine-DNA alkyltransferase (ATase) encoded by the Escherichia coli ogt gene . We demonstrate that, in close parallel with mutagenesis, the Ogt ATase sensitizes the bacteria to the lethal effects of these carcinogens, suggesting that one or more of the potentially mutagenic lesions induced by DBE and DBM in the presence of Ogt has additional lethal capacity . We further demonstrate that the sensitization to both lethality and mutagenesis by DBE and DBM is a property shared by other DNA alkyltransferases . This objective was accomplished by quantifying the induction of mutations and lethal events in ogt- ada- E . coli expressing an exogenous bacterial or mammalian ATase from a multicopy plasmid . Mammalian recombinant ATases enhanced the lethal and mutagenic actions of DBE and suppressed the lack of sensitivity of the vector-transformed bacteria to DBM . In most cases the order of effectiveness of the ATases ranked: murine > human > Ogt > rat . Further comparisons included the full-length Ada ATase from E . coli and a truncated Ada version (T-ada) that retains the O6-methylguanine binding domain of the protein . The full-length Ada ATase was effective in enhancing the lethality but not the mutagenicity induced by DBE and DBM . The T-ada ATase provided less sensitization than Ada to lethality by DBE, but of the three bacterial ATases T-ada yielded the highest sensitization to mutagenesis by this compound . T-ada and Ada ATases were in general less effective than the mammalian versions, with the exception of the rat recombinant ATase . The effectiveness of the different mammalian and bacterial ATases in promoting the deleterious actions of dibromoalkanes was compared with the effectiveness of these proteins in suppressing the lethal and mutagenic effects induced by N-nitroso-N-methylurea . The ability to sensitize E . coli to the lethal and mutagenic effects of DBE and DBM seems restricted to DNA alkyltransferase, since overexpression of thioredoxin (Trx) or glutaredoxin (Grx1) in ogt- ada- cells showed no effect, in spite of the reported potential of bioactive dihaloethane-derived species to alkylate Trx.

Braz J Med Biol Res, 1997 Jul, 30(7), 843 - 7
Fibronectin in the ascitic fluid of cirrhotic patients: correlation with biochemical risk factors for the development of spontaneous bacterial peritonitis; Mesquita RC et al.; Cirrhotic patients (23 with alcoholic cirrhosis, 5 with posthepatitic cirrhosis and 2 with cryptogenic cirrhosis) with ascites and portal hypertension were studied and divided into two groups corresponding to high or low risk to develop spontaneous bacterial peritonitis (SBP) related to the concentration of total protein in the ascitic fluid (A-TP): group I (high risk): A-TP < or = 1.5 g/dl and group II (low risk): A-TP > 1.5 g/dl . Fibronectin (FN), C3 and C4 concentrations were measured by radial immunodiffusion while total protein was measured by the biuret method . The mean values (group I vs group II) of C3 (12.59 +/- 4.72 vs 24.53 +/- 15.58 mg/dl), C4 (4.26 +/- 3.87 vs 7.26 +/- 4.14 mg/dl) and FN (50.47 +/- 12.49 vs 75.89 +/- 24.70 mg/dl) in the ascitic fluid were significantly lower (P < 0.05) in the group considered to be at high risk for SBP . No significant difference was observed in the plasma/ascites fibronectin ratio (3.91 +/- 1.21 vs 3.80 +/- 1.26) or gradient (131.46 +/- 64.01 vs 196.96 +/- 57.38) between groups . Fibronectin in ascites was significantly correlated to C3 (r = 0.76), C4 (r = 0.58), total protein (r = 0.73) and plasma FN (r = 0.58) (P < 0.05) . The data suggest that the FN concentration in ascites is related to the opsonic capacity of this fluid, and that its concentration in the ascitic fluid may be a biochemical risk factor indicator for the development of spontaneous bacterial peritonitis.

Appl Environ Microbiol, 1997 Nov, 63(11), 4612 - 6
Small-subunit rRNA genes and in situ hybridization with oligonucleotides specific for the bacterial symbionts in the larvae of the bryozoan Bugula neritina and proposal of "Candidatus endobugula sertula"; Haygood MG et al.; Larvae of the bryozoan Bugula neritina harbor bacterial symbionts . These symbionts were identified as a novel species of gamma-proteobacterium, based on ribosomal small-subunit rRNA gene sequences . In situ hybridization with oligonucleotides specific for the symbiont confirmed the origin of the sequence . The taxonomic status "Candidatus Endobugula sertula" is proposed for the larval symbiont.

Prev Vet Med, 1997 Sep, 32(1-2), 23 - 34
Risk factors for bacterial gill disease in young rainbow trout (Oncorhynchus mykiss) in North America; Bebak J et al.; A retrospective whole-population survey was used to investigate putative risk factors for bacterial gill disease (BGD) in young hatchery-reared rainbow trout in North America . Three sets of analyses were done . The first analysis included as cases all of the hatcheries in which there was at least one outbreak of BGD during the 2-year study interval, regardless of location of the outbreak in the hatchery . The case group for the second analysis was limited to hatcheries for which the BGD outbreak occurred inside the hatch house . The case group for the third analysis was limited to hatcheries for which the BGD outbreak occurred outside of the hatch house . For the logistic regression that combined all cases of BGD (regardless of location of the outbreak), there was a significant association between mortality from bacterial gill disease and previous experience with BGD outbreaks (odds ratio (OR) = 10.1; 95% confidence interval (CI) = 5.6, 18.2), being a commercial trout hatchery (OR = 5.2; 95% CI = 2.6, 10.4), and being a hatchery with an annual salmonid fish production of > 250,000 fish (OR = 2.9; 95% CI = 1.5, 5.7) . For BGD outbreaks that occurred in the hatch house, the presence of fish in the hatch house water supply significantly increased the odds of an outbreak (OR = 5.3; 95% CI = 2.2, 12.6), as did the use of ultraviolet radiation to disinfect the hatch house water (OR = 7.5; 95% CI = 2.2, 25.8), previous experience with bacterial gill disease (OR = 19.3; 95% CI = 7.9, 46.8), and being a commercial hatchery (OR = 7.7; 95% CI = 3.2, 18.6) . The odds of a BGD outbreak outside of the hatch house was significantly associated with previous experience with BGD (OR = 4.3; 95% CI = 2.2, 8.6) and with being a hatchery with an annual salmonid fish production > 50,000 pounds (OR = 2.5; 95% CI = 1.2, 5.1).

Adv Perit Dial, 1997, 13, 210 - 3
Lipopolysaccharide binding protein: a marker for intraperitoneal bacterial infection in patients with CAPD peritonitis; Schafer K et al.; During systemic infection, the serum lipopolysaccharide binding protein (LBP) binds to the lipid A component of bacterial endotoxins and facilitates its delivery to the CD 14 receptor on the cell surface of macrophages, where proinflammatory cytokines are released . There is no knowledge to date whether LBP is also present in the effluent of patients with continuous ambulatory peritoneal dialysis (CAPD)-associated peritonitis . We investigated the dialysis effluent of 37 patients with CAPD peritonitis for immunoreactive LBP, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-1 beta and compared the findings with the cytokine levels in 20 noninfected CAPD patients . The mean +/- SEM concentrations of LBP, TNF-alpha, and IL-1 beta were significantly higher in the effluent of patients with peritonitis than in noninfected CAPD effluent . In comparison to controls (0.23 +/- 0.05 microgram/mL), LBP was 0.68 +/- 0.13 microgram/mL in the effluent of patients with CAPD-associated infectious peritonitis . For TNF-alpha, levels were 0.50 +/- 0.25 pg/mL in the control effluent versus 124.7 +/- 46.6 pg/mL in the effluent of peritonitis patients . For IL-1 beta the levels were 0.24 +/- 0.14 pg/mL in the control effluent and 71.23 +/- 17.53 pg/mL in the peritonitis patients . Our findings demonstrate that LBP is significantly elevated in the effluent of CAPD patients during an episode of CAPD-associated peritonitis and might be used as a marker of intraperitoneal bacterial infection.

Nippon Rinsho, 1997 Oct, 55(10), 2633 - 9
{The role of cleavage activation of the hemagglutinin by host and bacterial proteases in the induction of the pathogenesis of influenza viruses}; Tashiro M; Infectivity and pathogenicity of influenza viruses are based on the interplay between the viral glycoprotein hemagglutinin (HA) and appropriate host proteases . HA receives its full biological activities by proteolytic cleavage of a precursor molecule at a definite cleavage site . Tryptase Clara, an arginine-specific protease secreted by the Clara cells in the bronchial epithelia, is a principal host protease responsible for the cleavage activation and pathogenicity of influenza viruses . Although influenza in normal individuals is usually confined to the upper respiratory tract, the infection often develops into fatal pneumonia in patients with chronic lung diseases, where bacterial infections often occur . Synergistic effects of bacterial infections on the pathogenesis of influenza viruses are described in regard to the cleavage activation of HA.

Semin Gastrointest Dis, 1997 Oct, 8(4), 200 - 9
Management of ascites in the patient with portal hypertension with emphasis on spontaneous bacterial peritonitis; Navasa M et al.; The reintroduction of paracentesis has modified the way in which patients with ascites are treated . Transjugular intrahepatic portosystemic shunt can be an alternative treatment for patients with refractory ascites and for those patients with hepatorenal syndrome, although more studies are needed to clarify its usefulness and safety . The use of more potent and less nephrotoxic antibiotics together with an earlier diagnosis have improved the outcome of patients with spontaneous bacterial peritonitis (SBP) . Oral antibiotics can be used in patients with SBP and good clinical conditions with an efficacy similar to that obtained with intravenous antibiotics . Prophylactic antibiotics in SBP should be restricted to cirrhotic patients at high risk, including bleeding cirrhotic patients, those with a past history of SBP, and those with low protein content in ascitic fluid . This chapter describes the management of ascites in patients with portal hypertension.

Clin Exp Immunol, 1997 Oct, 110(1), 72 - 8
Experimental immunization with anti-rheumatic bacterial extract OM-89 induces T cell responses to heat shock protein (hsp)60 and hsp70; modulation of peripheral immunological tolerance as its possible mode of action in the treatment of rheumatoid arthritis (RA); Bloemendal A et al.; OM-89 is a bacterial (Escherichia coli) extract used for oral administration in the treatment of RA . Given the evidence that immunity to bacterial heat shock antigens plays a critical role in the immunomodulation of arthritis and possibly inflammation in general, the purpose of the present studies was to evaluate the presence and immunogenicity of hsp in OM-89 . Furthermore, we studied the effects of OM-89 in an experimental arthritis, where hsp are known to have a critical significance in disease development . In rats immunization with OM-89 was found to lead to proliferative T cell responses to hsp60 and hsp70 of both E . coli and mycobacterial origin . Conversely, immunization with hsp antigens was also found to induce T cell reactivity specific for OM-89 . Based on this and the antigen specificity analysis of specific T cell lines, hsp70(DnaK) turned out to be one of the major immunogenic constituents of OM-89 . Parenteral immunization with OM-89 was found to reduce resistance to adjuvant arthritis (AA), whereas oral administration was found to protect against AA . Given the arthritis-inhibitory effect of oral OM-89 in AA, it is possible that peripheral tolerance is induced at the level of regulatory T cells with specificity for hsp . This may also constitute a mode of action for OM-89 as an arthritis-suppressive oral drug.

Am J Reprod Immunol, 1997 Oct, 38(4), 246 - 51
Regulation of decidual cell and chorion cell production of interleukin-10 by purified bacterial products; Dudley DJ et al.; PROBLEM: To determine whether cultured human decidual cells and chorion cells produce interleukin-10 (IL-10) after incubation with purified bacterial products . METHOD OF STUDY: Decidual cell cultures and chorion cell cultures were established by standard techniques . With confluence, monolayers of each culture were incubated with purified bacterial products, including various concentrations of lipopolysaccharide (LPS), lipid A, and lipoteichoic acid (LTA) for 16 hr in quadruplicate . Culture supernatants were collected and assayed for immunodetectable IL-10 by enzyme-linked immunoadsorbent assay (ELISA) . RESULTS: Both decidual cell cultures and chorion cell cultures produced significant quantities of IL-10 after stimulation with LPS, lipid A, and LTA . Cultures of decidual cells produced more IL-10 than did chorion cell cultures . CONCLUSIONS: Our data indicate that both maternal decidual cells and fetally derived chorion cells can produce IL-10 after incubation with bacterial virulence factors . This finding contrasts with our previous findings in which chorion cells did not produce IL-10 after stimulation with IL-1 beta, suggesting that chorion cell production after incubation with bacterial products is independent of IL-1 beta . We speculate that the contribution of anti-inflammatory IL-10 production by human gestational tissues to the inflammatory process in these tissues may be overcome or abrogated by the pro-inflammatory process.

Trends Microbiol, 1997 Oct, 5(10), 394 - 8
Bacterial avirulence proteins as triggers of plant disease resistance; Van den Ackerveken G et al.; Disease resistance in plants is often characterized by matching resistance and avirulence genes in host and pathogen, respectively . It has recently been shown that expression of bacterial avirulence genes in plants induces resistance gene-dependent defense reactions . The finding that avirulence proteins act inside plant cells represents a major advance in our understanding of host-pathogen specificity.

J Mol Biol, 1997 Oct 24, 273(2), 428 - 39
Residues of the cytoplasmic domain of MotA essential for torque generation in the bacterial flagellar motor; Zhou J et al.; The MotA protein of Escherichia coli is a component of the flagellum that functions, together with MotB, in transmembrane proton conduction . MotA and MotB are believed to form the stator of the flagellar motor . They are integral membrane proteins; MotA has a large (ca 22 kDa) domain in the cytoplasm, and MotB a much smaller one (ca 3 kDa) . Recent work suggests that cytoplasmically located parts of MotA and/or MotB might be present at the active site for torque generation in the motor . To test the proposal that the cytoplasmic domain of MotA functions in torque generation, and to identify the amino acid residues most important for function, we have carried out a mutational analysis of this domain . Using random mutagenesis, many mutations of cytoplasmic residues of MotA were isolated, which either abolish or impair torque generation . In most cases the residues affected are not conserved, and many of the replacements involve loss or gain of a proline residue, which suggests that these mutations disrupt function by altering the protein conformation rather than by directly affecting residues of an active site . Using site-directed mutagenesis, the conserved residues in the cytoplasmic domain of MotA were replaced, either singly or, in the case of charged residues, in various combinations . The results identify four residues of MotA that are important for motor function . These are Arg90 and Glu98, located in the cytoplasmic domain, and Pro173 and Pro222, located at the interface between the cytoplasmic domain and the membrane-spanning domain . Possible roles for these residues in torque generation are discussed .

J Pediatr, 1997 Sep, 131(3), 356 - 61
Influence of bacterial overgrowth and intestinal inflammation on duration of parenteral nutrition in children with short bowel syndrome; Kaufman SS et al.; OBJECTIVES: Massive intestinal resection results in short bowel syndrome and necessitates prolonged parenteral feeding . The purpose of this work was to assess the impact of late complications of short bowel syndrome, including intestinal bacterial overgrowth and enterocolitis, on the duration of parenteral nutrition (PN) in comparison with factors evident in the neonatal period . METHODS: Retrospective chart review . RESULTS: Of 49 children, 42 were weaned from parenteral nutrition after a treatment course of 17 +/- 14 months . In these 42, postresection small intestinal length equaled 81 +/- 65 cm; 45% had an ileocecal valve . Small intestinal length in the seven children who were PN dependent was 31 +/- 30 cm (p < 0.05); none had an ileocecal valve (p < 0.05) . Bacterial overgrowth occurred in all seven PN-dependent children and in 23 of 42 children eventually weaned from PN (p < 0.05) . When bacterial overgrowth was identified before weaning (n = 12), the duration pf PN was 28 +/- 17 months, but when bacterial overgrowth was first identified only after weaning (n = 11), the duration of PN was 16 +/- 13 months (p < 0.05) . Small intestinal inflammation correlated with bacterial overgrowth (r = 0.69) . Those children with severe enteritis identified before weaning remained on the PN regimen for 36 +/- 15 months, in comparison with 21 +/- 14 months in those with mild enteritis and 13 +/- 11 months in those without inflammation (p < 0.02) . CONCLUSIONS: Although the length of small intestine remaining after resection is the best immediate predictor of final success in terminating PN in children with short bowel syndrome, PN is prolonged by bacterial overgrowth and associated enteritis in those who will ultimately be weaned.

J Nutr Sci Vitaminol (Tokyo), 1997 Aug, 43(4), 445 - 54
Effect of dietary fiber on bowel mucosal integrity and bacterial translocation in burned rats; Nakamura T et al.; The response of the bowel mucosa to enteral formula supplemented with dietary fiber was examined in rats with 30% full-thickness burns . The rats were fed a standard enteral formula without fiber or with one of two types of fiber (insoluble soy fiber or soluble guar gum fiber) . Seventy-two hours after burn injury, the mesenteric lymph nodes were excised aseptically for bacterial culturing . Samples of the jejunum, ileum and cecum were also collected for histological examination . There were significantly fewer bacterial colonies in the lymph node cultures from rats given soy fiber compared to those from rats fed no fiber . In rats given soy fiber, the integrity of the bowel mucosa was maintained in the jejunum, ileum and cecum . In rats given guar gum fiber, however, the repair of mucosal erosions was observed in the jejunum and ileum as well as flattening of the cecal mucosa . These findings indicate that soy fiber is superior to guar gum fiber for maintaining bowel mucosal integrity and preventing bacterial translocation in burned rats receiving enteral feeding.

J Biol Chem, 1997 Oct 10, 272(41), 25583 - 90
TrwD, a protein encoded by the IncW plasmid R388, displays an ATP hydrolase activity essential for bacterial conjugation; Rivas S et al.; A 1.7-kilobase pair segment from the conjugative transfer region of plasmid R388 DNA was cloned and sequenced . It contained trwD, a gene essential for plasmid R388 conjugation, for expression of the conjugative W-pilus and for sensitivity to phage PRD1 . The deduced amino acid sequence of TrwD showed homology to the PulE/VirB11 superfamily of potential ATPases involved in various types of transport processes . A fusion of trwD with the glutathione S-transferase (GST) was constructed, and the resulting fusion protein was purified from overproducing bacteria . Factor Xa hydrolysis of GST-TrwD and further purification rendered TrwD protein with more than 95% purity . Antibodies raised against TrwD localized it both in the soluble fraction and in the outer membrane of Escherichia coli . TrwD is probably a peripheral outer membrane protein because it could be solubilized by increasing salt concentration to 0.5 M NaCl in the lysis buffer . Both purified GST-TrwD and TrwD could hydrolize ATP . ATPase activity increased 2-fold in the presence of detergent-phospholipid mixed micelles . To study the importance of the nucleotide-binding site, Walker box A (GXXGXGK(T/S)), present in TrwD, the conserved lysine residue was replaced by glutamine . The mutant protein, expressed and purified under the same conditions as the wild type, did not exhibit ATPase activity . TrwD(K203Q) was not able to complement the mutation in trwD of the R388 mutant plasmid, suggesting the essentiality of the ATPase activity of the protein in the conjugative process . Furthermore, the dominant character of this mutation suggested that GST-TrwD(K432Q) was still able to interact either with itself or with other component(s) of the conjugative machinery.

Protein Expr Purif, 1997 Oct, 11(1), 72 - 8
Bacterial expression and purification of recombinant Plasmodium yoelii circumsporozoite protein; Stratmann T et al.; We report the expression and purification of recombinant rodent malarial Plasmodium yoelii circumsporozoite surface protein (PyCSP) in Escherichia coli . To facilitate purification of the recombinant protein, the PyCSP was expressed as an amino-terminal fusion protein to glutathione S-transferase and as a carboxy-terminal fusion protein to a hexahistidyl tag . The expression of the fusion protein was controlled by the inducible tac promoter . Under optimal conditions the immunoreactive PyCSP represented approximately 0.04% of the total cell lysate . Western blot analysis probing with an anti-PyCSP antibody revealed a wide array of immunoreactive bands . Material isolated by affinity purification on glutathione-Sepharose 4B resin also contained multiple bands indicative of premature termination or carboxyl-terminal degradation . Analysis of protein retained on a nickel nitrilotriacetic acid resin revealed evidence of amino-terminal deleted material . Combining the two mild affinity purifications resulted in isolation of a single immunoreactive protein of approximate molecular weight of 96 kDa . We anticipate that the approach described in this study will facilitate the production of highly purified recombinant proteins.

Anal Chem, 1995 Jun 1, 67(11), 1824 - 30
Characterization of bacterial phospholipids by electrospray ionization tandem mass spectrometry; Smith PB et al.; A negative ion electrospray ionization tandem mass spectrometric technique was developed for the analysis of glycerophospholipids . Examination of the product ion mass spectrum of the deprotonated molecular ion provided sufficient information to identify both the class of glycerophospholipid and the molecular weights of the two fatty acid moieties . This technique was applied to the profiling of glycerophospholipids present in the chloroform/methanol extracts of four different bacterial species . The principal bacterial phospholipids detected by this technique were phosphatidylglycerols and diphosphatidylglycerols, accompanied by small amounts of phosphatidylethanolamines for two of the bacterial species examined . The fatty acid composition of the phosphatidylglycerols for each bacteria was determined by tandem mass spectrometry and presented graphically . Differences in the fatty acid composition for each bacterial species were readily apparent from a visual examination of the data sets.

Nat Biotechnol, 1997 Sep, 15(9), 859 - 65
Homologous recombination based modification in Escherichia coli and germline transmission in transgenic mice of a bacterial artificial chromosome; Yang XW et al.; Escherichia coli-based artificial chromosomes have become important tools for physical mapping and sequencing in various genome projects . The lack of a general method to modify these large bacterial clones, however, has limited their utility in functional studies . We developed a simple method to modify bacterial artificial chromosomes directly in the recombination-deficient E . coli host strain by homologous recombination for in vivo studies . The IRES-LacZ marker gene was introduced into a 131 kb BAC containing the murine zinc finger gene, RU49 . No rearrangements or deletions were detected in the modified BACs . Furthermore, transgenic mice were generated by pronuclear injection of the modified BAC, and germline transmission of the intact BAC has been obtained . Proper expression of the lacZ transgene in the brain has been observed, which could not be obtained with conventional transgenic constructs.

Rocz Panstw Zakl Hig, 1997, 48(2), 119 - 27
Bacterial mutagenicity of dithiocarbamate fungicide thiram; Rahden-Staron I et al.; In the present work, within a project of re-evaluation of authorized pesticides coordinated by PZH (National Institute of Hygiene) we aimed at looking for a mechanism of induction of chromosomal aberrations by thiram . We checked its ability to damage bacterial DNA.

Rocz Panstw Zakl Hig, 1997, 48(2), 111 - 7
Daminozide--lack of the genotoxic activity in the short-term bacterial tests; Rahden-Staron I et al.; Daminozide {ALAR} a plant growth regulator has been widely used on apples since the late 1960s . It has been identified as a possible carcinogen . Restrictions were ordered to reduce both application rates and allowable daminozide residue levels . Since conclusive scientific data necessary to characterize the risk of daminozide were not available, additional information on mutagenic activity of this compound was needed.

Biodegradation, 1997, 8(2), 105 - 11
Use of a luminescent bacterial biosensor for biomonitoring and characterization of arsenic toxicity of chromated copper arsenate (CCA); Cai J et al.; An arsenic oxyanion-inducible Escherichia coli chromosomal operon (arsRBC) has been previously identified . Construction of a luciferase transcriptional gene fusion (arsB::luxAB) showed that ars operon expression, plus concomitant cell luminescence, was inducible in a concentration-dependent manner by arsenic salts . The present study was conducted to evaluate the potential of the arsB::luxAB transcriptional gene fusion for use as a biosensor in monitoring the toxicity of arsenic compounds . Cultures from this gene fusion strain were exposed to increasing concentrations of the wood preservative chromated copper arsenate (CCA), as well as its constituents, sodium arsenate and chromated copper solution (CC) . Analysis of luciferase activity revealed that the arsB::luxAB gene fusion was expressed in response to CCA and sodium arsenate, but not to the CC solution . The detection limit of arsenic was found to be 0.01 microgram As/ml (10 parts per billion, 10 ppb) and therefore well within the range of environmental concerns . A greater induction of luminescence by arsenate was observed when cells were limited for phosphate, as phosphate can act as a competitive inhibitor of arsenate ions . Our results suggest that the E . coli arsB::luxAB fusion strain has a promising future as a specific and sensitive biosensor for monitoring bioavailable levels and toxicity of arsenic near sites where CCA-treated wood has been used.

Klin Lab Diagn, 1997 Jul, (7), 41 - 5
{Evaluation of the sensitivity and specificity of methods of rapid diagnosis in bacterial vaginosis}; Ankirskaia AS et al.; Bacterial vaginosis was diagnosed in 35.8% of 109 patients of a reproductive age complaining of discharge from the genital tract . In 33% of cases bacterial vaginosis was associated with vaginal candidiasis . The most sensitive and specific method of rapid diagnosis of bacterial vaginosis is microscopic examination of Gram-stained smears, which may be used as a diagnostic method, whose sensitivity and specificity are almost 100% . Such tests as pH-metry, amine test, "key" cells, and assessment of vaginal discharge (normal or abnormal), should be used in complex . They may be performed by the therapist screening patients to detect bacterial vaginosis.

Arch Otolaryngol Head Neck Surg, 1997 Oct, 123(10), 1103 - 10
RANTES is more prevalent in bacterial than in nonbacterial maxillary sinusitis: and P-selectin is preferentially up-regulated in diseased mucosae; Westergren V et al.; OBJECTIVE: To investigate the relationship of the clinical appearance, histological characteristics, bacterial culturing, and messenger RNA (mRNA) expression of RANTES, interleukin 6, and interleukin 12, as well as the occurrence of endothelial adhesion molecules, in inflammatory diseased maxillary sinus mucosa in critically ill patients . DESIGN: Prospective case series . SETTING: General intensive care unit and neurosurgical intensive care unit of a tertiary care hospital . SUBJECTS: Seven critically ill patients, nasotracheally intubated or tracheotomized, who received ventilator treatment for more than 7 days and treatment with antibiotics . INTERVENTIONS: Bilateral biopsy specimens of antral mucosa were obtained at sinoscopy . Reverse transcriptase-polymerase chain reaction was used to detect the cytokine mRNAs in situ on paraformaldehyde-fixed tissue, and intercellular adhesion molecule 1, vascular cell adhesion molecule 1, E-selectin, and P-selectin were analyzed by immunochemistry on frozen sections . Sampling of secretion and tissue from the antra was performed for bacterial culturing . RESULTS: Macroscopic and histological appearance varied and showed moderate to pronounced inflammation in 6 antra . All 4 bacterially infected antra showed mRNA RANTES (P=.005) . No correlation was found for interleukin 6 and interleukin 12 . Up-regulation of P-selectin in all cases and sparse expression of vascular cell adhesion molecule 1 indicate that the inflammation is chronic but nonallergic in type . CONCLUSION: We find an indication that RANTES is more prevalent in bacterial sinusitis.

J Bacteriol, 1997 Oct, 179(19), 6076 - 83
Convenient and reversible site-specific targeting of exogenous DNA into a bacterial chromosome by use of the FLP recombinase: the FLIRT system; Huang LC et al.; We have created a system that utilizes the FLP recombinase of yeast to introduce exogenous cloned DNA reversibly at defined locations in the Escherichia coli chromosome . Recombination target (FRT) sites can be introduced permanently at random locations in the chromosome on a modified Tn5 transposon, now designed so that the inserted FRT can be detected and its location mapped with base pair resolution . FLP recombinase is provided as needed through the regulated expression of its gene on a plasmid . Exogenous DNA is introduced on a cloning vector that contains an FRT, selectable markers, and a replication origin designed to be deleted prior to electroporation for targeting purposes . High yields of targeted integrants are obtained, even in a recA background . This system permits rapid and precise excision of the introduced DNA when needed, without destroying the cells . The efficiency of targeting appears to be affected only modestly by transcription initiation upstream of the chromosomal FRT site . With rare exceptions, FRTs introduced to the bacterial chromosome are targeted with high efficiency regardless of their location . The system should facilitate studies of bacterial genome structure and function, simplify a wide range of chromosomal cloning applications, and generally enhance the utility of E . coli as an experimental organism in biotechnology.

J Bacteriol, 1997 Oct, 179(19), 6028 - 34
Sequencing of a 1,3-1,4-beta-D-glucanase (lichenase) from the anaerobic fungus Orpinomyces strain PC-2: properties of the enzyme expressed in Escherichia coli and evidence that the gene has a bacterial origin; Chen H et al.; A 971-bp cDNA, designated licA, was obtained from a library of Orpinomyces sp . strain PC-2 constructed in Escherichia coli . It had an open reading frame of 738 nucleotides encoding LicA (1,3-1,4-beta-D-glucanase; lichenase) (EC 3.2.1.73) of 245 amino acids with a calculated molecular mass of 27,929 Da . The deduced amino acid sequence had high homology with bacterial beta-glucanases, particularly in the central regions and toward the C-terminal halves of bacterial enzymes . LicA had no homology with plant beta-glucanases . The genomic DNA region coding for LicA was devoid of introns . More than 95% of the recombinant beta-glucanase produced in E . coli cells was found in the culture medium and periplasmic space . A N-terminal signal peptide of 29 amino residues was cleaved from the enzyme secreted from Orpinomyces, whereas 21 amino acid residues of the signal peptide were removed when the enzyme was produced by E . coli . The beta-glucanase produced by E . coli was purified from the culture medium . It had a molecular mass of 27 kDa on sodium dodecyl sulfate-polyacrylamide gels . The Km and Vmax values with lichenin as the substrate at pH 6.0 and 40 degrees C were 0.75 mg/ml and 3,790 micromol/min/mg, respectively . With barley beta-glucan as the substrate, the corresponding values were 0.91 mg/ml and 5,320 micromol/min/mg . This enzyme did not hydrolyze laminarin, carboxymethylcellulose, pustulan, or xylan . The main products of lichenin and barley beta-glucan hydrolysis were triose and tetraose . LicA represented the first 1,3-1,4-beta-D-glucanase reported from fungi . The results presented suggest that licA of Orpinomyces had a bacterial origin.

Lab Anim Sci, 1997 Aug, 47(4), 354 - 61
Bacterial lipopolysaccharides induce peripheral nerve disturbances in rats that mimic human immune-mediated polyneuropathies; Brown RF et al.; A single injection of Escherichia coli lipopolysaccharide (LPS; i.v . and i.p.) reliably induced peripheral nerve disturbances in male Australian albino Wistar (AaW) rats . Signs developed 6 to 24 h after LPS inoculation and persisted only transiently . Most AaW rats had variable degrees of bilateral hind limb impairment, and rarely had forelimb, tail, or central impairment . Signs included gait abnormalities, proprioceptive loss, and to a lesser extent hind limb weakness and sensory deficits . Signs were more severe in male than female AaW rats and were induced in a number of genetically related rat strains (e.g., AaW and outbred Wistar and inbred Lewis rats, but not Sprague Dawley or inbred Fischer 344 rats) . Development and severity of these signs were found not be related to animal body weight, but were dependent on LPS dose . Signs were not associated with LPS-induced alterations in pain perception, or occurrence of spontaneous pain, as indexed by tail-flick and hot-plate tests . Taken together, these data indicate that LPS induced transient peripheral nerve disturbances in rats, the severity of which was influenced by genetic, sex-related, and dose-related factors.

J Cell Sci, 1997 Sep, 110 ( Pt 18), 2141 - 54
Interaction of Bartonella henselae with endothelial cells results in bacterial aggregation on the cell surface and the subsequent engulfment and internalisation of the bacterial aggregate by a unique structure, the invasome; Dehio C et al.; Vascular colonisation by Bartonella henselae may cause vaso-proliferative tumour growth with clumps of bacteria found in close association with proliferating endothelial cells . By using B . henselae-infected human umbilical vein endothelial cells as an in vitro model for endothelial colonisation, we report here on a novel mechanism of cellular invasion by bacteria . First, the leading lamella of endothelial cells establishes cellular contact to sedimented bacteria and mediates bacterial aggregation by rearward transport on the cell surface . Subsequently, the formed bacterial aggregate is engulfed and internalised by a unique host cellular structure, the invasome . Completion of this sequence of events requires 24 hours . Cortical F-actin, intercellular adhesion molecule-1 and phosphotyrosine are highly enriched in the membrane protrusions entrapping the bacterial aggregate . Actin stress fibres, which are anchored to the numerous focal adhesion plaques associated with the invasome structure, are typically found to be twisted around its basal part . The formation of invasomes was found to be inhibited by cytochalasin D but virtually unaffected by nocodazole, colchicine or taxol, indicating that invasome-mediated invasion is an actin-dependent and microtubuli-independent process . Bacterial internalisation via the invasome was consistently observed with several clinical isolates of B . henselae, while a spontaneous mutant obtained from one of these isolates was impaired in invasome-mediated invasion . Instead, this mutant showed increased uptake of bacteria into perinuclear localising phagosomes, suggesting that invasome-formation may interfere with this alternative mechanism of bacterial internalisation . Internalisation via the invasome represents a novel paradigm for the invasion of bacteria into host cells which may serve as a cellular colonisation mechanism in vivo, e.g . on proliferating and migrating endothelial cells during Bartonella-induced vaso-proliferative tumour growth.

Int J Syst Bacteriol, 1997 Oct, 47(4), 1145 - 56
Discovery and classification of ecological diversity in the bacterial world: the role of DNA sequence data; Palys T et al.; All living organisms fall into discrete clusters of closely related individuals on the basis of gene sequence similarity . Evolutionary genetic theory predicts that in the bacterial world, each sequence similarity cluster should correspond to an ecologically distinct population . Indeed, surveys of sequence diversity in protein-coding genes show that sequence clusters correspond to ecological populations . Future population surveys of protein-coding gene sequences can be expected to disclose many previously unknown ecological populations of bacteria . Sequence similarity clustering in protein-coding genes is recommended as a primary criterion for demarcating taxa.

Int J Syst Bacteriol, 1997 Oct, 47(4), 1112 - 7
Borrelia burgdorferi sensu stricto, a bacterial species "made in the U.S.A."?
Marti Ras N, Postic D, Foretz M, Baranton G.
Among the three main species of Borrelia burgdorferi sensu lato associated with Lyme borreliosis, B . burgdorferi sensu stricto (B . burgdorferi) is the sole species present both in North America and in Europe, where Borrelia garinii and Borrelia afzelii also occur . The greater genetic diversity together with the greater clinical polymorphism observed in the Old World suggests that this is the birthplace of the complex B . burgdorferi sensu lato . However, the genetic proximity of some North American and European B . burgdorferi strains in quite mystifying . A previous study of the whole genome (M . Foretz, D . Postic, and G . Baranton, Int . J . Syst . Bacteriol . 47:11-18, 1997) compared the diversity of North American and European B . burgdorferi strains . To further investigate the geographical origin and the migration of B . burgdorferi, we have focused on the study of the single variable and highly adaptive gene ospC . Both approaches demonstrated the greater diversity of North American strains and the close relatedness between European strains and between some isolates from the two areas . We discuss the significance of these features and suggest that they might be evidence of the anteriority of North American B . burgdorferi strains.

J Biotechnol, 1997 Sep 16, 57(1-3), 49 - 57
Trichoderma reesei cellobiohydrolase I with an endoglucanase cellulose-binding domain: action on bacterial microcrystalline cellulose; Srisodsuk M et al.; Cellulolytic enzymes consist of distinct catalytic and cellulose-binding domains (CBDs) . The presence of a CBD improves the binding and activity of cellulases on insoluble substrates but has no influence on their activities on soluble substrates . Structural and biochemical studies of a fungal CBD from Trichoderma reesei cellobiohydrolase I have revealed a wedge shaped structure with a flat cellulose binding surface containing three essential tyrosine residues . The face of the wedge is strictly conserved in all fungal CBDs while many differences occur on the other face of the wedge . Here we have studied the importance of these differences on the function of the T . reesei CBHI by replacing its CBD by a homologous CBD from the endoglucanase, EGI . Our data shows that, apart from slightly improved affinity of the hybrid enzyme, the domain exchange does not significantly influence the function of CBHI.

Clin Infect Dis, 1997 Aug, 25(2), 211 - 4
Quadriplegia complicating Escherichia coli meningitis in a newborn infant: case report and review of 22 cases of spinal cord dysfunction in patients with acute bacterial meningitis; Moffett KS et al.; We report a case of Escherichia coli meningitis complicated by spinal cord dysfunction in a neonate . This very rare complication of bacterial meningitis was probably caused by ischemia of the cord resulting from vasculitis . We review the 22 other reports of patients with this complication and discuss its pathogenesis.

Biochim Biophys Acta, 1997 Aug 22, 1321(2), 149 - 56
Light-induced electrogenic events associated with proton uptake upon forming QB- in bacterial wild-type and mutant reaction centers; Brzezinski P et al.; Light-induced voltage changes (electrogenic events) were measured in wild-type and site-directed mutants of reaction centers (RCs) from Rhodobacter sphaeroides oriented in a lipid monolayer adsorbed to a Teflon film . A rapid increase in voltage associated with charge separation was followed by a slower increase attributed to proton transfer from solution to protonatable amino-acid residues in the vicinity of the QB site . In native reaction centers the proton-transfer voltage had a pH-dependent amplitude with two peaks at pH 4.5 and pH 9.7, respectively . In the Glu-L212-->Gln RCs the high-pH peak was absent, whereas in the Asp-L213-->Asn RCs the low-pH peak was absent and the high-pH peak was shifted to lower pH by about 1.3 pH units . The amplitudes of the electrogenic phases as a function of pH follow approximately the measured proton uptake from solution (P.H . McPherson, M.Y . Okamura, G . Feher, Biochim . Biophys . Acta, vol . 934, 1988, pp . 348-368) and are ascribed to proton transfer to amino acid residues upon QB- formation . The peak around pH 9.7 is ascribed to proton uptake predominantly by Glu-L212 and the peak around pH 4.5 to proton uptake predominantly by Asp-L213 or a residue strongly interacting with Asp-L213.

Int Surg, 1997 Apr-Jun, 82(2), 134 - 6
Comparison of bacterial translocation during traumatic shock and hemorrhagic shock in rats; Sun Y et al.; Traumatic shock has been classified as a kind of hypovolemic shock similar to hemorrhagic shock . Since bacterial translocation has been observed in shock, this study investigated the difference in bacterial translocation during traumatic shock and hemorrhagic shock, and considered this effect on lung injury during sepsis . METHODS: Forty-eight male or female Sprague-Dawley rats were divided into 2 groups, hemorrhagic shock and traumatic shock . Bacterial translocation, endotoxin, and blood gas were evaluated . Alterations of the lungs morphologically and functionally were observed . RESULTS: Traumatic shock induced more bacterial translocation and endotoxemia from the gut . Blood gas analysis shows a more severe disorder in traumatic shock than in hemorrhagic shock . Pathological morphologic changes of lungs were more severe in traumatic shock than in hemorrhagic shock . CONCLUSIONS: Traumatic shock cause more bacterial translocation and endotoxemia which subsequently caused serial pathological alterations in lung morphologically and functionally than pure hemorrhagic shock does . These results suggest that this trauma activates more severe mechanism to damage lungs.

Nucleic Acids Res, 1997 Oct 1, 25(19), 3917 - 24
Ectopic mitotic recombination in Drosophila probed with bacterial beta-galactosidase gene-based reporter transgenes; Bartsch S et al.; Plasmids were constructed to investigate homologous mitotic recombination in Drosophila cells . Heteroalleles containing truncated but overlapping segments of the bacterial beta-galactosidase gene (lacZ) were positioned either on separate plasmids or as direct repeats on the same chromosome . Recombination reconstituted a functional lacZgene leading to expression of LacZ+activity detectable by histochemical staining . High extrachromosomal recombination (ECR) frequencies between unlinked heteroalleles were observed upon transient co-transfection into Drosophila melanogaster Schneider line 2 (S2) cells . Stably transfected cells containing the lacZ heteroalleles linked on a chromosome exhibited intrachromosomal recombination (ICR) frequencies two orders of magnitude lower than ECR frequencies . Recombination was inducible by exposing the cells to ethyl methanesulphonate or mitomycin C . Recombination products were characterized by multiplex PCR analysis and unequal sister chromatid recombination was found as the predominant mechanism reconstituting the lacZ gene . To investigate recombination in vivo imaginal disc cells from transgenic larvae carrying the reporter gene on the X chromosome were isolated and stained for LacZ+ activity . The presence of a few LacZ+ clones indicated that mitotic recombination events occurred at frequencies two orders of magnitude lower than the corresponding event in cultured cells and late during larval development.

Am J Obstet Gynecol, 1997 Sep, 177(3), 532 - 5
Correlation between cervical cytologic results and Gram stain as diagnostic tests for bacterial vaginosis; Davis JD et al.; OBJECTIVE: Our purpose was to determine the reliability of the Papanicolaou smear in making the diagnosis of bacterial vaginosis with the vaginal Gram stain used as the diagnostic standard . STUDY DESIGN: We conducted a prospective, blinded, cross-sectional study of 210 consecutive patients referred to the Colposcopy Clinic for evaluation of abnormal cervical cytologic results . Each patient had a standard Papanicolaou smear and Gram stain of vaginal discharge . The sensitivity, specificity, positive predictive value, and negative predictive value of the Papanicolaou smear were determined with the Gram stain used as the standard for diagnosis of bacterial vaginosis . RESULTS: Of the 210 patients, 80 (38.1%) had Gram stains that were positive for bacterial vaginosis and 118 (56.2%) had negative Gram stains . Twelve (5.7%) had intermediate Gram stains that were also considered negative . Of the 80 patients with positive Gram stains, 44 had cervical smears consistent with bacterial vaginosis and 36 had negative smears . Of the 130 patients with negative Gram stains, two had a positive cervical smear . Therefore, compared to the Gram stain, cervical cytologic test results had a sensitivity of 55% and a specificity of 98% . The respective positive predictive and negative predictive values were 96% and 78% . CONCLUSION: Compared to Gram stain of vaginal secretions, the cervical Papanicolaou smear has fair sensitivity (55%) and excellent positive predictive value (96%) in diagnosing bacterial vaginosis.

J Biolumin Chemilumin, 1997 Jan-Feb, 12(1), 15 - 20
Superoxide anion reacts with enzyme intermediate in the bacterial luciferase reaction competitive with intramolecular electron transfer; Wada N et al.; Addition of KO2 in dimethyl sulfoxide (DMSO) to the in vitro bacterial luciferase reaction subsequent to its initiation resulted in a biphasic decay of light emission . The first and more rapid phase is attributed to quenching by DMSO . With DMSO alone the continuing decay is kinetically the same as in a control reaction . With KO2 added the second decay phase is more rapid and dependent on the KO2 concentration . The enhanced decay is attributed to superoxide anion generated from KO2 reacting without light emission with an enzyme peroxy intermediate, breaking down of the peroxide bond through intermolecular electron transfer from the superoxide anion, in competition with an intramolecular electron transfer from the N(5) position of the flavin ring, which normally leads to the production of the excited luciferase-dihydroflavin-4a-hydroxide.

Biochemistry, 1997 Sep 30, 36(39), 11556 - 63
Invariant amino acids in the Mur peptide synthetases of bacterial peptidoglycan synthesis and their modification by site-directed mutagenesis in the UDP-MurNAc:L-alanine ligase from Escherichia coli; Bouhss A et al.; The comparison of the amino acid sequences of 20 cytoplasmic peptidoglycan synthetases (MurC, MurD, MurE, MurF, and Mpl) from various bacterial organisms has allowed us to detect common invariants: seven amino acids and the ATP-binding consensus sequence GXXGKT/S all at the same position in the alignment . The Mur synthetases thus appeared as a well-defined class of closely functionally related proteins . The conservation of a constant backbone length between certain invariants suggested common structural motifs . Among the other enzymes catalyzing a peptide bond formation driven by ATP hydrolysis to ADP and Pi, only folylpoly-gamma-l-glutamate synthetases presented the same common conserved amino acid residues, except for the most N-terminal invariant D50 . Site-directed mutageneses were carried out to replace the K130, E174, H199, N293, N296, R327, and D351 residues by alanine in the MurC protein from Escherichia coli taken as model . For this purpose, plasmid pAM1005 was used as template, MurC being highly overproduced in this genetic setting . Analysis of the Vmax values of the mutated proteins suggested that residues K130, E174, and D351 are essential for the catalytic process whereas residues H199, N293, N296, and R327 were not . Mutations K130A, H199A, N293A, N296A, and R327A led to important variations of the Km values for one or more substrates, thereby indicating that these residues are involved in the structure of the active site and suggesting that the binding order of the substrates could be ATP, UDP-MurNAc, and alanine . The various mutated murC plasmids were tested for their effects on the growth, cell morphology, and peptidoglycan cell content of a murC thermosensitive strain at 42 degrees C . The observed effects (complementation, altered morphology, and reduced peptidoglycan content) paralleled more or less the decreased values of the MurC activity of each mutant.

Biochemistry, 1997 Oct 7, 36(40), 12216 - 26
In bacterial reaction centers rapid delivery of the second proton to QB can be achieved in the absence of L212Glu; Miksovska J et al.; In the reaction center (RC) of Rhodobacter capsulatus, residue L212Glu is a component of the pathway for proton transfer to the reduced secondary quinone, QB . We isolated phenotypic revertants of the photosynthetically incompetent (PS-) L212Glu-->Gln mutant; all of them retain the L212Glu-->Gln substitution and carry a second-site mutation: L227Leu-->Phe, L228Gly-->Asp, L231Arg-->Cys, or M231Arg-->Cys . We also characterized the L212Ala strain, which is a phenotypic revertant of the PS- L212Glu-L213Asp-->Ala-Ala mutant . The activities of the RCs of these strains--all of which lack L212Glu--were studied by flash-induced absorption spectroscopy . At pH 7.5, the rate of second electron transfer in the L212Q mutant is comparable to the wild-type rate . However, this mutant shows a marked decrease in the rate of cytochrome oxidation under strong continuous illumination and a very slow phase (0.66 s-1) of the proton transfer kinetics following the second flash, indicating that transfer of the second proton to QB is slowed more than 1000-fold . The levels of recovery of the functional capabilities in the revertant RCs vary widely; their rates of cytochrome oxidation were intermediate between those of the wild-type and the L212Q mutant . The kinetics of proton transfer following the second flash show a significant recovery in the L212Q + M231C and L212A RCs (330-540 s-1), but the L212Q + L227F RCs recover this function only partially . Compensation for the lack of L212Glu in revertant RCs is discussed in terms of (i) conformational changes that could allow water molecules to approach closer to QB and/or (ii) the increase in the negative electrostatic environment and the resultant rise in the free energy level of QB- that is induced by the mutations . The stoichiometries of H+/QB- proton uptake below pH 7.5 in the L212Q mutant, the L212Q + M231C revertant, and the wild-type strains are essentially equivalent, suggesting that L212Glu is protonated at neutral pH in wild-type RCs . This is also supported by the P+QB- charge recombination data . Comparison of H+/QB- proton uptake data with those obtained previously for the stoichiometries of H+/QA- proton uptake {Miksovska, J., Maroti, P., Tandori, J., Schiffer, M., Hanson, D . K., Sebban, P . (1996) Biochemistry 35, 15411-15417} suggests that L212Glu is the key to the electrostatic and perhaps structural interaction between the two quinone sites.

FEBS Lett, 1997 Sep 8, 414(2), 319 - 22
Bacterial beta-galactosidase and human dystrophin genes are expressed in mouse skeletal muscle fibers after ballistic transfection; Zelenin AV et al.; Ballistic transfection, based on cell and tissue bombardment by the tungsten and gold microparticles covered with the gene DNA, was used for the delivery of a bacterial beta-galactosidase and a full-length cDNA copy of the human dystrophin genes into mouse skeletal muscles . CMV-lacZ, SV40-lacZ, LTR-lacZneo and full-length cDNA dystrophin (pDMD-1, approximately 16 kb) in eukaryotic expression vector pJ OMEGA driven by mouse leukaemia virus promotor (pMLVDy) were used throughout the studies . Musculus glutaeus superficialis of C57BL/6J and quadriceps femoris of mdx male mice were opened surgically under anesthesia and bombarded by means of the gene-gun technique originally developed by us . Different mixtures of gold and tungsten particles at ratios of 4:1, 1:1, 1:4 were applied . X-gal assay revealed marked beta-gal activity, both in total muscles and whole muscle fibers on histological sections, up to three months after transfection . The most intensive staining was observed after SV40-lacZ delivery . No staining was detected with LTR-lacZneo DNA as well as in untreated muscles . The higher tungsten particle concentration in the bombardment mixture correlated with more intense X-gal staining . At the gold/tungsten ratio of 1:4 the microparticles penetrated the musculus glutaeus superficialis and transfected the underlying musculus glutaeus medius as well . Immuno-cytochemical assay for human dystrophin revealed dystrophin positive myofibers (DPM) in the bombarded area up to two months after transfection . The proportion of DMP varied from 2.5% on day 17 up two 5% on day 60 after bombardment compared to only 0.5% in the control mdx mice . These results suggest the applicability of particle bombardment for gene delivery into muscle fibers.

J Biochem (Tokyo), 1997 Aug, 122(2), 322 - 9
Construction, bacterial expression, and characterization of hapten-specific single-chain Fv and alkaline phosphatase fusion protein; Suzuki C et al.; We have designed and constructed a bacterial expression vector to produce a fusion protein of hapten-specific single-chain Fv (ScFv) and alkaline phosphatase (PhoA) in Escherichia coli . The ScFv gene was assembled using genes encoding the heavy and light chain variable domains of anti-NP (4-hydroxy-3-nitrophenyl acetyl) mouse monoclonal antibody . The ScFv gene was then fused to the 5' terminus of the E . coli PhoA coding region . The expressed fusion protein ScFv(NP)-PhoA was purified using an NP affinity column, and gel-filtration . Characterization of the fusion protein was then performed . The estimated molecular weight by gel filtration was approximately 151 kDa, suggesting the dimerization of the protein . Kinetic constants of ScFv(NP)-PhoA were calculated and compared with those of wild-type PhoA . The k(cat) values of ScFv(NP)-PhoA and wild-type PhoA were 103 (s(-1)) and 96.1 (s(-1)), respectively, showing that PhoA activity was somewhat increased by tethering the molecules . The equilibrium binding constant of ScFv(NP)-PhoA was determined using two different haptens, NP-capronate and NIP(3-iodo-4-hydroxy-5-nitrophenyl acetyl) by means of fluorescence quenching measurements . The obtained binding constants were 2.2 x 10(5) (M-1) for NP-capronate and 1.O x 10(6) (M(-1)) for NIP, respectively . No apparent difference in binding constants was seen between ScFv(NP) and ScFv(NP)-PhoA, showing that sufficient specificity and binding affinity were retained when ScFv(NP) was tethered to alkaline phosphatase . ScFv(NP)-PhoA can be used to detect nanogram concentrations of NP-BSA in ELISA without the use of chemically conjugated secondary antibodies.

Am J Perinatol, 1997 Sep, 14(8), 487 - 90
Screening and treatment of bacterial vaginosis during pregnancy: a model for determining benefit; Glantz JC; Bacterial vaginosis is associated with an increased risk of preterm birth . The treatment of bacterial vaginosis has recently been shown to decrease the risk of preterm delivery, especially in high-risk populations . However, the benefit of routine screening and treatment in the general population is uncertain . Using the information from several recent studies, a graph and nomogram generated from a mathematical model allow the obstetrician to determine the benefit of routine screening and treatment of bacterial vaginosis in his or her obstetrical population, depending on the prevalence of bacterial vaginosis and the total preterm delivery rate in that obstetrician's practice . If the prevalence of bacterial vaginosis and the incidence of preterm delivery are low, then routine screening would be expected to prevent small numbers of preterm births, and therefore may not be cost-effective.

Patol Fiziol Eksp Ter, 1997 Jul-Sep, (3), 37 - 9
{Effect of proteolysis inhibitors on various bacterial pathogens and the course of the pyo-inflammatory process}; Chilingirov RKh; Some proteolytic inhibitors were shown to be able to suppress the growth and development of a series of bacterial agents, the drug gordox being the most active among them . The effects of proteolytic inhibitors on the course of an inflammatory process experimentally simulated were studied . Endolymphatic (intranodular) injection of proteolytic inhibitors increased the activity of agents responsible for the body's nonspecific resistance and sharply reduced intoxication, by providing effective treatment of inflammation.

J Biol Chem, 1997 Oct 3, 272(40), 24913 - 20
Alkene monooxygenase from Xanthobacter strain Py2 . Purification and characterization of a four-component system central to the bacterial metabolism of aliphatic alkenes; Small FJ et al.; Alkene monooxygenase from Xanthobacter strain Py2 is an inducible enzyme that catalyzes the O2- and NADH-dependent epoxidation of short chain (C2 to C6) alkenes to their corresponding epoxides as the initial step in the utilization of aliphatic alkenes as carbon and energy sources . In the present study, alkene monooxygenase has been resolved from the soluble fraction of cell-free extracts into four components, each of which has been purified to homogeneity, that are obligately required for alkene epoxidation activity . The four required components are 1) a monomeric 35.5-kDa protein containing 1 mol of FAD and a probable 2Fe-2S center; 2) a 13.3-kDa ferredoxin containing a Rieske-type 2Fe-2S cluster; 3) an 11-kDa monomeric protein that contains no detectable cofactors; and 4) a 212-kDa alpha2beta2gamma2 multimeric protein containing four atoms of nonheme iron . The 35.5-kDa protein has been characterized as an NADH reductase . The physiological electron acceptor for the reductase was the Rieske-type ferredoxin, which is proposed to be an intermediate electron carrier between the reductase and terminal catalytic component of the system . The 212-kDa protein was specifically inactivated in cell-free extracts by the mechanism-based inactivator propyne, suggesting that it is the catalytic component and contains the active site(s) for O2 activation and alkene epoxidation . The subunit structure and metal analysis of this component suggest that it contains two diiron centers, one for each alphabetagamma protomeric unit . No specific enzymatic activities could be assigned for the 11-kDa protein, but this component was obligately required for steady-state alkene epoxidation . The alkene monooxygenase components were expressed during growth of Xanthobacter Py2 on aliphatic alkenes or epoxides and repressed during growth on other carbon sources . The electron transfer components of alkene monooxygenase were highly specific: other reductase activities present in Xanthobacter were incapable of transferring electrons to the Rieske-type ferredoxin or substituting for the reductase in the alkene monooxygenase complex . Likewise, other bacterial and plant ferredoxins were unable to substitute for the Rieske-type ferredoxin in mediating electron transfer to the oxygenase . The biochemical properties of alkene monooxygenase described in this study suggest that this enzyme combines elements of both the well-characterized aromatic dioxygenase (two-component electron transfer scheme) and methane monooxygenase (small regulatory protein and diiron oxygenase) multicomponent enzyme systems.

Int J Food Microbiol, 1997 Jul 22, 37(2-3), 131 - 5
Modelling the heat stress and the recovery of bacterial spores; Mafart P et al.; After heat treatment, the temperature incubation and the medium composition, (pH and sodium chloride content) influence the capacity of injured spores to repair heat damage . The concept of heat resistance D- (decimal reduction time) and z-values (temperature increase which results in a ten fold reduction of the D value) is not sufficient and the ratio of spore recovery after incubation should be considered in calculations used in thermal processing of food . This paper aims to derive a model describing the recovery of injured spores as a function of both the heat treatment intensity and the environmental conditions . According to data from numerous investigators, when spores are incubated in unfavorable conditions, the ratio of cell recovery and the apparent D-value are reduced . Moreover the ratio of the apparent D-value and the estimated in optimal incubation D-value is constant and independent of the heat treatment conditions . Beyond these observations it is shown that the ratio of cell recovery with respect to the heat treatment F-value (exposure time, in minutes, at 121.1 degrees C which results in the same destruction ratio that the considered heat treatment does) is linear and can be quantified by using two factors independent of the heat treatment: the gamma-factor reflects the degree of precariousness due to the heat stress while the epsilon-factor reflects more intrinsically the incubation conditions without previous heat treatment . The gamma-factor varies as a function of the incubation temperature according to an Arrhenius law.

Am J Respir Cell Mol Biol, 1997 Sep, 17(3), 344 - 52
Expression of lung vascular and airway ICAM-1 after exposure to bacterial lipopolysaccharide; Beck-Schimmer B et al.; Airway instillation of bacterial lipopolysaccharide (LPS) into rat lungs induces neutrophil accumulation, which is known to be intercellular adhesion molecule-1 (ICAM-1)-dependent . In the present study, ICAM-1 messenger RNA (mRNA) of whole lung was found to increase by 20-fold in this inflammatory model . This increase was reduced by 81% after treatment of animals with anti-tumor necrosis factor-alpha (TNF-alpha) antibody and by 37% after treatment with anti-interleukin-1 (IL-1) antibody . The same interventions reduced whole-lung ICAM-1 protein by 85% and 25%, respectively . The studies were extended to assess the locale in lung of ICAM-I upregulation . Lung vascular ICAM-1 content, which was assessed by vascular fixation of {125I}anti-ICAM-1, rose 4-fold after airway instillation of LPS . This rise was also TNF-alpha-dependent . Under the same experimental conditions, fixation of {125I}anti-ICAM-1 to airway surfaces increased 11-fold in a TNF-alpha-dependent manner . In situ hybridization and immunohistochemical analyses of lung tissue revealed ICAM-1 upregulation in the bronchiolar epithelium and in peribronchiolar smooth muscle . Soluble ICAM-1 could also be detected in bronchoalveolar lavage fluids (BALFs) of animals after intratracheal instillation of LPS . Retrieved alveolar macrophages showed a small, significant, and transient increase in surface expression of ICAM-1 . These data indicate, at the very least, a dual compartmentalized (vascular and airway) upregulation of ICAM-1 after airway instillation of LPS . This upregulation requires TNF-alpha and IL-1 . The functional significance of upregulated airway ICAM-1 remains to be determined.

Arch Biochem Biophys, 1997 Sep 15, 345(2), 342 - 54
A general strategy for the expression of recombinant human cytochrome P450s in Escherichia coli using bacterial signal peptides: expression of CYP3A4, CYP2A6, and CYP2E1; Pritchard MP et al.; Heterologous expression of unmodified recombinant human cytochrome P450 enzymes (P450s) in Escherichia coli has proved to be extremely difficult . To date, high-level expression has only been achieved after altering the 5'-end of the native cDNA, resulting in amino acid changes within the P450 protein chain . We have devised a strategy whereby unmodified P450s can be expressed to high levels in E . coli, by making NH2-terminal translational fusions to bacterial leader sequences . Using this approach, we initially tested two leader sequences, pelB and ompA, fused to CYP3A4 . These were compared with an expression construct producing a conventional NH2-terminally modified CYP3A4 (17alpha-3A4) . Both leader constructs produced spectrally active, functional protein . Furthermore, the ompA-3A4 fusion gave higher levels of expression, and a marked improvement in the recovery of active P450 in bacterial membrane fractions, when compared with 17alpha-3A4 . We then tested the ompA leader with CYP2A6 and CYP2E1, again comparing with the conventional (17alpha-) approach . As before, the leader construct produced active enzyme, and, for CYP2E1 at least, gave a higher level of expression than the 17alpha-construct . The ompA fusion strategy thus appears to represent a significant advance for the expression of P450s in E . coli, circumventing the previous need for individual optimization of P450 sequences for expression.

Behring Inst Mitt, 1997 Feb, (98), 434 - 41
Bacterial ADP-ribosylating toxins: form, function, and recombinant vaccine development; Burnette WN; No products of the biotechnology revolution will likely have a greater legacy than recombinant vaccines . Clinical efficacy trials of new acellular pertussis vaccines have recently been completed; among them, a vaccine containing a genetically modified pertussis toxin showed superior effectiveness in protection against disease caused by Bordetella pertussis . The foundations for this vaccine derive from the work of many investigators, but most notably: Japanese researchers who demonstrated the potential for subcomponents of B . pertussis, and particularly pertussis toxin, to confer protective immunity; research teams in Italy and the United States who cloned and sequenced the pertussis toxin operon; and our own group who molecularly dissected the toxin molecule to produce recombinant analogs of this heterohexameric protein that retained protective immunogenicity yet lacked the intrinsic enzyme activity that results in the adverse reactogenic effects of immunization . Another result of the research leading to this new pertussis vaccine is an intimate understanding of the relationship between form and function in the ADP-ribosylating toxins with AB5 architecture, including the structure of their catalytic domains their immunologic and adjuvant properties, characteristics and possible pathologic consequences of host cell receptor recognition, and the assembly and subunit interactions of these complex multimeric proteins.

Behring Inst Mitt, 1997 Feb, (98), 390 - 9
Bacterial lipopeptides constitute efficient novel immunogens and adjuvants in parenteral and oral immunization; Bessler WG et al.; Synthetic lipopeptide analogues derived from the N-terminus of bacterial lipoprotein constitute potent B-lymphocyte and macrophage/monocyte activators in vitro . In vivo they act as immunoadjuvants in parenteral and oral immunization when administered in combination with antigens . When added to bacterial or viral vaccines, lipopeptides markedly enhance the vaccine effect . After the coupling of lipopeptides to haptens or non immunogenic low molecular mass antigens, a specific antibody response is induced often after only one application of the conjugate . The response can be further enhanced by introducing haplotype specific T helper cell epitopes into the conjugate . Lipopeptide antigen conjugates can also be applied as synthetic vaccines that give protection e.g . against foot-and-mouth-disease . The novel chemically well defined lipopeptides described here can be synthesized in gram amounts with high purity and reproducibility; they are non-toxic and can be stored for long time even at room temperature . For veterinary application, by replacing Freund's adjuvant, side reactions and inflammatory processes are avoided.

Biochim Biophys Acta, 1997 Aug 29, 1336(2), 171 - 9
Effects of the anti-bacterial peptide cecropin B and its analogs, cecropins B-1 and B-2, on liposomes, bacteria, and cancer cells; Chen HM et al.; Custom designed analogs of the natural anti-bacterial peptide cecropin B (CB) have been synthesized; cecropin B-1 (CB-1) was constructed by replacing the C-terminal segment (residues 26 to 35) with the N-terminal sequence of CB (positions 1 to 10 which include five lysine residues) . The second analog, CB-2, is identical to CB-1 except for the insertion of a Gly-Pro residue pair between Pro-24 and Ala-25 . These peptides were used to investigate their anti-liposome, anti-bacterial and anti-cancer activities . The strength of anti-liposome activity is reduced two- to three-fold when the analogs are used instead of natural CB based on DL50 analysis . Similarly, the potency of these analogs on certain bacteria is about two- to four-fold lower than those of CB based on LC measurements . In contrast, on leukemia cancer cells, the potency of CB-1 and CB-2 is about two- to three-fold greater than that of natural CB based on IC50 measurements . All CB, CB-1 and CB-2 peptides have comparable helix contents according to CD measurements . These results indicate that the designed cationic lytic peptides, having extra cationic residues, are less effective in breaking liposomes and killing bacteria but more effective in lysing cancer cells . The possible interpretations for these observations are discussed.

FEBS Lett, 1997 Sep 1, 414(1), 33 - 8
Sequence analysis and bacterial production of the anti-c-myc antibody 9E10: the V(H) domain has an extended CDR-H3 and exhibits unusual solubility; Schiweck W et al.; The cDNAs for the two variable domains of the antibody 9E10 were cloned from the hybridoma cell line . A chimeric 9E10 Fab fragment was produced in E . coli under control of the tightly controlled tetracycline promoter . The functional Fab fragment was isolated in a single step via a His6-tag, which also served for its recognition by a nickel chelate-alkaline phosphatase conjugate . Thus, the recombinant Fab fragment permitted the immunochemical detection of the myc tag in a sandwich ELISA . The dissociation constant for the interaction with the myc tag peptide was determined as 80 +/- 5 nM by fluorescence titration . In an attempt to produce the smaller 9E10 Fv fragment it was found that its V(H) domain alone can be readily isolated from E . coli as a soluble protein . This unusual behaviour may be explained by the 18 amino acid-long CDR-H3 and could be of value in the design of 'single domain' antibodies.

Anal Chem, 1997 Sep 15, 69(18), 3697 - 701
Simultaneous topographic and fluorescence imagings of recombinant bacterial cells containing a green fluorescent protein gene detected by a scanning near-field optical/atomic force microscope; Tamiya E et al.; A scanning near-field optical/atomic force microscope (SNOAM) system was applied for simultaneous topographic and fluorescence imaging of biological samples in air and liquid . The SNOAM uses a bent optical fiber simultaneously as a dynamic mode atomic force microscopy cantilever and as a scanning near-field optical microscopy probe . Optical resolution of this system was about 50-100 nm in fluorescence mode for fluorescent latex beads on a quartz glass plate . Green fluorescent protein (GFP) is a convenient indicator of transformation and should allow cells to be separated by fluorescence-activated cell sorting . The gene coding to GFP was cloned in recombinant Escherichia coli . The SNOAM system used 458- or 488-nm irradiation from a multiline Ar ion laser for excitation of GFP, since a native GFP has been known to give a maximum at 395 nm and a broad absorption spectrum until 500 nm . Topographic and fluorescence images of recombinant E . coli were obtained simultaneously with a high spatial resolution which was apparently better than that of a conventional confocal microscope . A nanoscopic GFP fluorescence spectrum was obtained by positioning the optical fiber probe above the bright area of the E . coli cells . Comparing topographic and fluorescence images, it can be seen that individual E . coli cells expressed different fluorescence intensities . Fluorescence obtained by SNOAM indicated that GFP oxidation possibly occurred near the cell surface . A SNOAM system also indicated the possibility of precise imaging of native cells in liquid.

J Neurosci Res, 1997 Sep 1, 49(5), 569 - 75
Regulation of nerve growth factor secretion and mRNA expression by bacterial lipopolysaccharide in primary cultures of rat astrocytes; Galve-Roperh I et al.; The present work was undertaken to study the effect of bacterial lipopolysaccharide (LPS), a potent activator of the host inflammatory response, on the synthesis of nerve growth factor (NGF) by newborn rat brain astrocytes . Treatment of primary rat astroglial cells cultured in chemically defined medium with LPS resulted in a dose-dependent accumulation of NGF mRNA, and an increased release of NGF protein in the cell medium . NGF mRNA levels were maximal after 24 hr of stimulation (8-fold increase), whereas extracellular NGF peaked after 72 hours of treatment (17-fold increase) . This dramatic increase of extracellular NGF was abrogated if cells were treated with actinomycin D or cycloheximide, a fact which implies that the accumulation of extracellular NGF by LPS-treated cells requires DNA transcription and RNA translation . Stimulation of NGF synthesis and secretion was: (i) unaffected by treatment with the protein kinase C inhibitor bisindolylmaleimide, and (ii) prevented by forskolin and 3-isobutyl-1-methylxanthine, two agents which increase cAMP levels . Inhibition of LPS effect was also obtained with apigenin, a proposed inhibitor of the mitogen-activated protein kinase pathway . Results thus show that LPS stimulates NGF synthesis by astroglial cells through a mechanism that is independent of protein kinase C (PKC), antagonized by cAMP-elevating agents, and probably mediated by the mitogen-activated protein kinase cascade . The data raise the possibility that LPS exerts stimulatory effects on NGF synthesis that are independent of those elicited by astrocyte-derived inflammatory lymphokines such as IL-1beta, TNF alpha or TGF beta1.

FEMS Microbiol Rev, 1997 Jul, 20(3-4), 249 - 59
Effect of flagellates on free-living bacterial abundance in an organically contaminated aquifer; Kinner NE et al.; Little is known about the role of protists in the saturated subsurface . Porous media microcosms, containing bacteria and protists, were used to determine whether flagellates from an organically contaminated aquifer could substantively affect the number of free-living bacteria (FLB) . When flagellates were present, the 3-40% maximum breakthrough of fluorescently labelled FLB injected into the microcosms was much lower than the 60-130% observed for killed controls . Grazing and clearance rates (3-27 FLB flag-1 h-1 and 12-23 nl flag-1 h-1, respectively) calculated from the data were in the range reported for flagellates in other aqueous environments . The data provide evidence that flagellate bacterivory is an important control on groundwater FLB populations.

Inflamm Res, 1997 Aug, 46(8), 287 - 91
Comparison of hypotensive response to aggregated IgG or to bacterial LPS in rats; Jenei B et al.; OBJECTIVE AND DESIGN: Rats treated with aggregated IgG (Aggr.) become "refractory" to the hypotensive action of a second dose of Aggr . The objective of this study was to assess the responsiveness of animals pretreated with Aggr . to bacterial LPS and vice versa . MATERIAL OR SUBJECTS: Female Wistar rats (250-300 g) were used . Each experiment was carried on at least 4 animals . TREATMENT: A human IgG preparation containing 30% aggregates (10-16 mg/100 g) or E . coli serotype 0111.B4 (0.005-mg/100 g) was administered i.v . Certain groups of animals were pretreated with 1 mg/100 g GdCl3 or with 10 mg/100 g pentoxyphylline (PTX) . METHODS: Arterial blood pressure was monitored in the carotis-using a polyethylene cannula and an electronic tension meter . Tumor necrosis factor alpha (TNF-alpha) activity was estimated by the use of an L-929 cell cytotoxicity assay . RESULTS: Pretreatment of rats with a sublethal dose of LPS impaired the hypotensive reaction of the animals to Aggr . Rats male "refractory" to Aggr . reacted to the injection of LPS with hypotension and a second phase milder than in the controls . Hypotension could not be elicited by Aggr . in rats pretreated with GdCl3 . The same pretreatment had no effect on the first phase of hypotension induced by intravenous injection of LPS, whilst a mitigation of the second phase was observed . Infusion of PTX immediately prior to Aggr . administration prevented the drop of blood pressure . A sizeable level of TNF-alpha was detected only later than blood pressure had reached its minimum level following Aggr . administration . CONCLUSIONS: Hypotension induced by LPS may involve a macrophage population broader than that responsible for the vascular action of Aggr . The data presented do not support a primary role for TNF-alpha in Aggr . induced hypotension.

Nucleic Acids Res, 1997 Aug 15, 25(16), 3242 - 7
From footprint to toeprint: a close-up of the DnaA box, the binding site for the bacterial initiator protein DnaA; Speck C et al.; The Escherichia coli DnaA protein binds as a monomer to the DnaA box, a 9 bp consensus sequence: 5'-TTA/TTNCACA . To assess the contribution of individual bases to protein binding we probed the DnaA-DnaA box complex with the uracil-DNA glycosylase (UDG) footprinting technique . (i) dU at the positions of T2, T4, T7' or T9' completely inhibits DnaA binding to the DnaA box . At these positions the methyl groups of the thymine residues are essential for successful DnaA binding, indicating protein contact with the major groove . Additionally they are positioned exactly on one side of the helix . (ii) dU at the position of T1 or at three T residues adjacent to the 9 bp core sequence of the DnaA box allows DnaA binding . These positions are protected from UDG digestion as revealed by the footprint assay . (iii) dU at the position of T3' on the complementary strand of teh box 5'-TTATCCACA was not protected from UDG digestion in DNA-DnaA complexes . Therefore, DnaA cannot contact the major groove at this position . In addition, a slight bend of the DnaA box towards UDG would help the enzyme to access this site.

J Biol Chem, 1997 Sep 19, 272(38), 23938 - 45
Avian retrovirus U3 and U5 DNA inverted repeats . Role Of nonsymmetrical nucleotides in promoting full-site integration by purified virion and bacterial recombinant integrases; Vora AC et al.; The U3 and U5 termini of linear retrovirus DNA contain imperfect inverted repeats that are necessary for the concerted insertion of the termini into the host chromosome by viral integrase . Avian myeloblastosis virus integrase can efficiently insert the termini of retrovirus-like DNA donor substrates (480 base pairs) by a concerted mechanism (full-site reaction) into circular target DNA in vitro . The specific activities of virion-derived avian myeloblastosis virus integrase and bacterial recombinant Rous sarcoma virus (Prague A strain) integrase (approximately 50 nM or less) appear similar upon catalyzing the full-site reaction with 3'-OH recessed wild type or mutant donor substrates . We examined the role of the three nonsymmetrical nucleotides located at the 5th, 8th, and 12th positions in the U3 and U5 15-base pair inverted repeats for their ability to modify the full-site and simultaneously, the half-site strand transfer reactions . Our data suggest that the nucleotide at the 5th position appears to be responsible for the 3-5-fold preference for wild type U3 ends over wild type U5 ends by integrase for concerted integration . Additional mutations at the 5th or 6th position, or both, of U3 or U5 termini significantly increased (approximately 3 fold) the full-site reactions of mutant donors over wild type donors.

Trends Microbiol, 1997 Sep, 5(9), 360 - 3
Probing bacterial gene expression within host cells; Valdivia RH et al.; The study of bacterial gene expression in the host environment is critical to our understanding of the disease process . New research tools, such as luciferase and green fluorescent protein, provide the means to measure bacterial responses to the intracellular environment with minimal perturbations and with single-cell resolution.

Appl Environ Microbiol, 1997 Sep, 63(9), 3698 - 702
Simultaneous determination of gene expression and bacterial identity in single cells in defined mixtures of pure cultures; Poulsen LK et al.; A protocol was developed to achieve the simultaneous determination of gene expression and bacterial identity at the level of single cells; a chromogenic beta-galactosidase activity assay was combined with in situ hybridization of fluorescently labelled oligonucleotide probes to rRNA . The method allows monitoring of gene expression and quantification of beta-galactosidase activity in single cells.

Arch Intern Med, 1997 Sep 8, 157(16), 1825 - 31
Human immunodeficiency virus disease-related neutropenia and the risk of hospitalization for bacterial infection; Jacobson MA et al.; BACKGROUND: Neutropenia is common in patients with human immunodeficiency virus (HIV) disease . However, the degree of risk for serious bacterial infections associated with various levels of neutropenia in patients with HIV disease is not well defined . METHODS: A retrospective analysis of databases containing demographic information for patients attending the San Francisco General Hospital HIV outpatient clinic, test results reported by the hospital's clinical laboratory, and the San Francisco General Hospital inpatient International Classification of Diseases, Ninth Revision (ICD-9) hospital discharge diagnosis codes from October 1, 1992, through November 30, 1993 . Risk window time periods were defined, encompassing dates that consecutive absolute neutrophil counts (ANCs) occurred in a single ANC stratum . One risk window at the lowest ANC stratum for each patient was analyzed for hospitalizations with ICD-9 codes indicating bacterial infections . A 5% random sample of medical records was reviewed for end point validation . RESULTS: Codes from ICD-9 had 98% and 96% positive and negative predictive values, respectively, for meeting National Institute of Allergy and Infectious Diseases Division of AIDS {acquired immunodeficiency syndrome} clinical trial end point definitions for bacterial infections . Among 2047 evaluable patients, a significant increase in the incidence of hospitalization for serious bacterial infections was observed for those in the ANC strata of 500 to 749 X 10(6)/L and below . The 95% confidence intervals for the incidence of hospitalization associated with each ANC stratum below 500 X 10(6)/L did not overlap with that for any stratum of 750 X 10(6)/L or higher (22-117 vs 0.4-19 patient hospitalizations per 10000 days at risk, respectively) . A multivariate analysis revealed only the severity and duration of neutropenia and black race to be significant end point predictors . CONCLUSION: Among 2047 patients with HIV disease, significantly higher risks of hospitalization for bacterial infections were associated with ANCs lower than 750 X 10(6)/L, especially for ANCs lower than 500 X 10(6)/L.

Fungal Genet Biol, 1997 Jun, 21(3), 337 - 47
A large-insert (130 kbp) bacterial artificial chromosome library of the rice blast fungus Magnaporthe grisea: genome analysis, contig assembly, and gene cloning; Zhu H et al.; Magnaporthe grisea (Hebert) Barr causes rice blast, one of the most devastating diseases of rice (Oryza sativa) worldwide . This fungus is an ideal organism for studying a number of aspects of plant-pathogen interactions, including infection-related morphogenesis, avirulence, and pathogen evolution . To facilitate M . grisea genome analysis, physical mapping, and positional cloning, we have constructed a bacterial artificial chromosome (BAC) library from the rice infecting strain 70-15 . A new method was developed for separation of partially digested large-molecular-weight DNA fragments that facilitated library construction with large inserts . The library contains 9216 clones, with an average insert size of 130 kbp (> 25 genome equivalents) stored in 384-well microtiter plates that can be double spotted robotically on to a single nylon membrane . Several unlinked single-copy DNA probes were used to screen 4608 clones in the library and an average of 13 (minimum of 6) overlapping BAC clones was found in each case . Hybridization of total genomic DNA to the library and analysis of individual clones indicated that approximately 26% of the clones contain single-copy DNA . Approximately 35% of BAC clones contained the retrotransposon MAGGY . The library was used to identify BAC clones containing a adenylate cyclase gene (mac1) . In addition, a 550-kbp contig composed of 6 BAC clones was constructed that encompassed two adjacent RFLP markers on chromosome 2 . These data show that the BAC library is suitable for genome analysis of M . grisea . Copies of colony hybridization membranes are available upon request.

Proc Natl Acad Sci U S A, 1997 Sep 2, 94(18), 9568 - 72
DNA bending and the initiation of transcription at sigma54-dependent bacterial promoters; Carmona M et al.; We have examined the effects on transcription initiation of promoter and enhancer strength and of the curvature of the DNA separating these entities on wild-type and mutated enhancer-promoter regions at the Escherichia coli sigma54-dependent promoters glnAp2 and glnHp2 on supercoiled and linear DNA . Our results, together with previously reported observations by other investigators, show that the initiation of transcription on linear DNA requires a single intrinsic or induced bend in the DNA, as well as a promoter with high affinity for sigma54-RNA polymerase, but on supercoiled DNA requires either such a bend or a high affinity promoter but not both . The examination of the DNA sequence of all nif gene activator- or nitrogen regulator I-sigma54 promoters reveals that those lacking a binding site for the integration host factor have an intrinsic single bend in the DNA separating enhancer from promoter.

Curr Biol, 1997 Sep 1, 7(9), R573 - 5
Bacterial cytokinesis: let the light shine in; Lutkenhaus J; Recent application of fluorescence microscopy to the study of the bacterial cell cycle has revealed the existence of a cytoskeletal element - once thought to occur only in eukaryotic cells - that mediates cytokinesis, and possibly another involved in chromosome segregation.

Mol Mar Biol Biotechnol, 1997 Sep, 6(3), 268 - 77
Molecular phylogenetics of bacterial endosymbionts and their vestimentiferan hosts; Feldman RA et al.; Vestimentiferan tube worms from deep-sea hydrothermal vents and cold-water seeps rely entirely on sulfur-oxidizing bacterial endosymbionts for nutriment . We examined host-symbiont co-evolution by comparing phylogenetic trees from symbiont 16S ribosomal DNA and host mitochondrial COI genes . The endosymbionts comprised two distinct clades, one associated with tube worms from basaltic vent habitats and the other associated with tube worms from sedimented seep-like environments . Within each symbiont clade, 16S rDNA sequences were nearly identical, suggesting that vent vestimentiferans share a single endosymbiont species that is distinct from the seep endosymbiont species . A third endosymbiont type, related to the seep species, was found in a tube worm collected from a whale carcass . Our results are consistent with a horizontal model of symbiont transmission.

Arch Biochem Biophys, 1997 Sep 1, 345(1), 135 - 42
Expression, purification, and initial characterization of human Yes protein tyrosine kinase from a bacterial expression system; Sun G et al.; Protein tyrosine kinase Yes is a cellular homolog of v-Yes, the oncogenic protein product of avian sarcoma virus Y73 . Yes is a member of the Src family and its activation has been associated with several types of human cancer . Human Yes has not been previously characterized enzymatically . To carry out biochemical characterizations of this enzyme, we expressed it as a fusion protein with glutathione S-transferase in Escherichia coli, to allow purification in a single step . The affinity-purified GST-Yes has a specific activity of 1.3 nmol min-1 mg-1 with polyE4Y as substrate and Km values of 100 microg ml-1 for polyE4Y and 70 microM for ATP-Mg . The enzyme has a preference for magnesium over manganese ion for maximal activity . The divalent metal cation serves two essential functions for the activity of Yes: one as a part of the phosphate-donating substrate ATP-Mg and the other as an essential activator . The enzyme undergoes autophosphorylation without apparent activation . Finally, we show that the enzyme is inactivated by incubation with protein tyrosine kinase Csk in an ATP-Mg-dependent manner, indicating that cellular Yes can be regulated by Csk phosphorylation . These represent the first biochemical characterization of human Yes protein tyrosine kinase.

Epidemiology, 1997 Sep, 8(5), 571 - 4
Gastric acid, acid-suppressing drugs, and bacterial gastroenteritis: how much of a risk?
Garcia Rodriguez LA, Ruigomez A.
Recent studies have reported an association between acid-suppressing drugs (histamine H2 receptor antagonists and proton pump inhibitors) and development of infectious gastroenteritis . We conducted a case-control study nested in a cohort of more than 170,000 ever-users of acid-suppressing drugs to examine the association between acid-suppressing drugs and bacterial gastroenteritis, using data from the General Practice Research Database in the United Kingdom . We identified 374 confirmed cases of bacterial gastroenteritis and 2,000 randomly sampled controls from the study cohort . There was little increased risk of bacterial gastroenteritis among users of acid-suppressing drugs {relative risk (RR) = 1.1; 95% confidence interval (CI) = 0.8-1.4} . Omeprazole "single users" had an RR of 1.6 (95% CI = 1.0-2.4), but this effect was not observed among those using only omeprazole during the last year (RR = 1.1; 95% CI = 0.7-1.9) . We did not find any dose or treatment duration response . These data do not support a major role for acid reduction in the development of bacterial gastroenteritis.

J Biol Chem, 1997 Aug 29, 272(35), 21706 - 12
Ent-kaurene synthase from the fungus Phaeosphaeria sp . L487 . cDNA isolation, characterization, and bacterial expression of a bifunctional diterpene cyclase in fungal gibberellin biosynthesis; Kawaide H et al.; ent-Kaurene is the first cyclic diterpene intermediate of gibberellin biosynthesis in both plants and fungi . In plants, ent-kaurene is synthesized from geranylgeranyl diphosphate via copalyl diphosphate in a two-step cyclization catalyzed by copalyl diphosphate synthase and ent-kaurene synthase . A cell-free system of the fungus Phaeosphaeria sp . L487 converted labeled geranylgeranyl diphosphate to ent-kaurene . A cDNA fragment, which possibly encodes copalyl diphosphate synthase, was isolated by reverse transcription-polymerase chain reaction using degenerate primers based on the consensus motifs of plant enzymes . Translation of a full-length cDNA sequence isolated from the fungal cDNA library revealed an open reading frame for a 106-kDa polypeptide . The deduced amino acid sequence shared 24 and 21% identity with maize copalyl diphosphate synthase and pumpkin ent-kaurene synthase, respectively . A fusion protein produced by expression of the cDNA in Escherichia coli catalyzed the two-step cyclization of geranylgeranyl diphosphate to ent-kaurene . Amo-1618 completely inhibited the copalyl diphosphate synthase activity of the enzyme at 10(-6) M, whereas it did not inhibit the ent-kaurene synthase activity even at 10(-4) M . These results indicate that the fungus has a bifunctional diterpene cyclase that can convert geranylgeranyl diphosphate into ent-kaurene . They may be separate catalytic sites for the two cyclization reactions.

Cell, 1997 Aug 8, 90(3), 491 - 500
In vivo observation of polypeptide flux through the bacterial chaperonin system; Ewalt KL et al.; The quantitative contribution of chaperonin GroEL to protein folding in E . coli was analyzed . A diverse set of newly synthesized polypeptides, predominantly between 10-55 kDa, interacts with GroEL, accounting for 10%-15% of all cytoplasmic protein under normal growth conditions, and for 30% or more upon exposure to heat stress . Most proteins leave GroEL rapidly within 10-30 s . We distinguish three classes of substrate proteins: (I) proteins with a chaperonin-independent folding pathway; (II) proteins, more than 50% of total, with an intermediate chaperonin dependence for which normally only a small fraction transits GroEL; and (III) a set of highly chaperonin-dependent proteins, many of which dissociate slowly from GroEL and probably require sequestration of aggregation-sensitive intermediates within the GroEL cavity for successful folding.

Cell, 1997 Aug 8, 90(3), 415 - 24
Cell type-specific phosphorylation and proteolysis of a transcriptional regulator controls the G1-to-S transition in a bacterial cell cycle; Domian IJ et al.; The global transcriptional regulator CtrA controls multiple events in the Caulobacter cell cycle, including the initiation of DNA replication, DNA methylation, cell division, and flagellar biogenesis . CtrA is a member of the response regulator family of two component signal transduction systems and is activated by phosphorylation . We report here that this phosphorylation signal enters the cell cycle at mid S phase . In addition, CtrA function is modulated by temporally and spatially controlled proteolysis . When an active CtrA protein is present at the wrong time in the cell cycle, owing to expression of a mutant CtrA derivative that is active in the absence of phosphorylation and is not turned over during the cell cycle, the G1-to-S transition is blocked and the cell cycle aborts . Thus, both phosphorylation and proteolysis are critical determinants of bacterial cell cycle control in a manner that is analogous to the control of the eukaryotic cell cycle.

FEBS Lett, 1997 Aug 4, 412(3), 563 - 7
Structural and functional characterisation of two proteolytic fragments of the bacterial protein toxin, pneumolysin; Morgan PJ et al.; Proteolytic cleavage of the bacterial protein toxin pneumolysin with protease K creates two fragments of 37 and 15 kDa . This paper describes the purification of these two fragments and their subsequent physical and biological characterisation . The larger fragment is directly involved in the cytolytic mechanism of this pore-forming protein, via membrane binding and self-association . The smaller fragment lacks ordered structure or discernible activity.

Dig Dis Sci, 1997 Aug, 42(8), 1587 - 92
Improvement in specificity of {14C}d-xylose breath test for bacterial overgrowth; Lewis SJ et al.; The aim of the study was to determine whether the specificity of the {14C}d-xylose breath test could be improved, by excluding false-positive tests due to premature colonic metabolism of the {14C}d-xylose caused by rapid colonic transit . Forty-seven patients with suspected small bowel bacterial overgrowth were investigated by (1) aspiration and culture of duodenal fluid and (2) a {14C}d-xylose breath test . Those with either a positive duodenal culture or breath test had a repeat {14C}d-xylose breath test given with one of three transit markers (barium, Gastrografin or 99mTc-labeled tin colloid) to determine if the site of metabolism was in the small bowel or colon . Fourteen patients had positive duodenal cultures, four of whom had a negative {14C}d-xylose breath test, 15 patients had a positive {14C}d-xylose breath test, three of which were due to colonic metabolism of the xylose . Where transit markers were used, 14C was detectable in the breath and serum before barium had entered the small bowel, thus the barium did not comigrate with the xylose . Gastrografin accelerated small bowel transit, leading to malabsorption of the xylose in the small intestine and subsequent colonic metabolism of the xylose . 99mTc-labeled tin colloid had no obvious disadvantages and appeared to be the marker of choice . The use of a transit marker increased the specificity of the {14C}d-xylose breath test from 85% to 94% . The specificity of the {14C}d-xylose breath test for the detection of small bowel bacterial overgrowth is improved to greater than 90% by the use of an appropriate transit marker.

Diabetologia, 1997 Aug, 40(8), 902 - 9
Oral insulin for diabetes prevention in NOD mice: potentiation by enhancing Th2 cytokine expression in the gut through bacterial adjuvant; Hartmann B et al.; Oral administration of insulin suppresses the development of diabetes in nonobese diabetic (NOD) mice and deviates the cytokine balance in the islets of Langerhans from a Th1 to a Th2 type cytokine pattern . However, the effect of oral insulin is limited and disease suppression is limited to a narrow dose range . Therefore we tried to improve the outcome of suboptimal insulin dosing by bacterial adjuvant . Mice treated with a suboptimal dose of oral insulin showed no change in diabetes incidence although a shift from Th1 towards Th2 cytokine expression occurred in inflamed islets . Significant suppression of diabetes development was only seen in NOD mice receiving both, insulin and the bacterial preparation OM-89 as adjuvant . OM-89 is a protein extract of Escherichia coli, with nonspecific immunostimulatory properties . Potentiation of the effect of oral insulin by the adjuvant was associated with upregulation of interleukin (IL)-4 Th2 cells in infiltrated islets and sustained local IL-2 gene expression . RT PCR analyses of cytokine expression in the gut showed a clear deviation to Th2 type reactivity and downregulation of inducible nitric oxide (NO) synthase (iNOS) expression by the bacterial adjuvant but not by oral insulin alone . Since macrophages are the primary target cells of adjuvant action we tested its effect on mouse macrophages in vitro . Treatment with OM-89 induced transient release of tumour necrosis factor alpha and nitrite but rendered macrophages refractory to restimulation by the potent macrophage activator lipopolysaccharide . In conclusion, the protective effect of oral insulin can be potentiated by pretreatment with the bacterial adjuvant OM-89 . This effect correlates with enhanced Th2 cytokine and decreased iNOS gene expression in the gut, probably due to the downregulation of proinflammatory mediators by exposure to the adjuvant.

Clin Transplant, 1997 Aug, 11(4), 271 - 4
Bacterial translocation in organ donors: clinical observations and potential risk factors; Kane TD et al.; Thirty-nine solid-organ donors were evaluated to determine the incidence of bacterial translocation to mesenteric lymph nodes . In addition, clinical variables from 59 local recipients of renal allografts from these donors were examined to assess whether translocation in donors was associated with increased morbidity in the recipients of organs from node-positive donors . Ileocecal lymph node cultures were positive in 18 of 39 donors (46%) . Sixteen donors (41%) were hypotensive {systolic blood pressure (SBP) < 90 mmHg} and 27 (69%) received blood product transfusions before organ donation . The presence of hypotension and blood product transfusion were associated with positive and negative cultures, respectively . In 24 (41%) of 59 organs transplanted from donors with periods of hypotension, significantly more (16 of 24, 67%) were associated with positive lymph node cultures than with negative cultures (8 of 24, 33%; p = 0.029) . In recipients of organs from node-positive versus node-negative donors there was a trend toward higher incidence of infection (32% vs . 25%), need for hemodialysis post-transplant (29% vs . 23%), graft loss within 1 yr (24% vs . 19%), and lack of blood transfusion prior to organ procurement (43% vs . 23%), although these variables were not significantly different between the groups . Hypotension or inadequate resuscitation may contribute to increased bacterial translocation to mesenteric lymph nodes . The overall impact upon the recipients of organs from donors with demonstrable translocation to lymph nodes remains undefined.

Trends Microbiol, 1997 Aug, 5(8), 323 - 6
DNA supercoiling and bacterial adaptation: thermotolerance and thermoresistance; Tse-Dinh YC et al.; When bacterial cells are shifted to higher temperatures their degree of DNA supercoiling changes . Topoisomerases are involved in bacterial adaptation to environmental changes requiring rapid shifts in gene expression . This role in heat shock has been elucidated by genetic studies on the Escherichia coli topA gene and its sigma 32-dependent promoter, P1 . Other studies have shown that certain gyrA mutants have increased thermoresistance.

Trends Microbiol, 1997 Aug, 5(8), 309 - 13
Natural functions of bacterial multidrug transporters; Neyfakh AA; Bacteria express several multidrug transporters that recognize structurally dissimilar toxic molecules and expel them from cells . These transporters may have evolved to protect bacteria from diverse environmental toxins or to transport specific physiological compounds with the ability to expel drugs being only a fortuitous side effect.

Am J Gastroenterol, 1997 Aug, 92(8), 1335 - 8
Luminal antigliadin antibodies in small intestinal bacterial overgrowth; Riordan SM et al.; OBJECTIVE: Elevated antigliadin antibody levels in small intestinal luminal secretions of subjects with normal or only mildly abnormal small intestinal histology are considered indicative of "latent" or "potential" celiac disease . The purpose of this study was to determine whether small intestinal bacterial overgrowth (SIBO) might provide an alternative explanation for positive luminal antigliadin antibodies in such subjects . METHODS: Twenty-six adult subjects without predisposition to disturbed mucosal immunity were investigated with culture of small intestinal luminal secretions . Luminal total IgA and IgA-antigliadin antibody concentrations were measured by radial immunodiffusion and indirect enzyme immunoassay, respectively . Local mucosal counts of IgA-plasma cells were determined by immunohistochemistry . Small intestinal histology and intraepithelial lymphocyte counts were assessed by light microscopy . Corresponding serum antigliadin antibody concentrations were determined . RESULTS: SIBO was present in 17/26 (65.4%) subjects . No subject with SIBO had villous atrophy . Luminal total IgA concentrations (p < 0.0005), mucosal IgA-plasma cell counts (p < 0.01), and intraepithelial lymphocyte counts (p < 0.01) were significantly increased in subjects with SIBO . Luminal IgA-antigliadin antibodies were detected in 6/17 (35.3%) subjects with SIBO and 0/9 (0%) subjects without SIBO . Luminal IgA-antigliadin antibody concentrations correlated significantly with luminal total IgA levels (p < 0.01) but not with serum values (p < 0.1) . Serum IgG-antigliadin antibody concentrations were elevated in 2/6 (33.3%) subjects with SIBO and positive luminal antigliadin antibodies . CONCLUSIONS: SIBO may be an alternative explanation to "latent" or "potential" celiac disease for positive luminal antigliadin antibodies in subjects with either normal or only mildly abnormal small intestinal histology, even when serum antigliadin antibody concentrations are elevated . Positive luminal antigliadin antibodies in SIBO probably occur as epiphenomena in the context of a graded mucosal immune response to local bacterial antigens.

Biophys J, 1997 Aug, 73(2), 703 - 21
Protein turbines . I: The bacterial flagellar motor; Elston TC et al.; The bacterial flagellar motor is driven by a flux of ions between the cytoplasm and the periplasmic lumen . Here we show how an electrostatic mechanism can convert this ion flux into a rotary torque . We demonstrate that, with reasonable parameters, the model can reproduce many of the experimental measurements.

Appl Environ Microbiol, 1997 Aug, 63(8), 3286 - 90
Glutathione S-transferase-encoding gene as a potential probe for environmental bacterial isolates capable of degrading polycyclic aromatic hydrocarbons; Lloyd-Jones G et al.; Homologs of the glutathione S-transferase (GST)-encoding gene were identified in a collection of aromatic hydrocarbon-degrading Sphingomonas spp . isolated from New Zealand, Antarctica, and the United States by using PCR primers designed from the GST-encoding gene of Sphingomonas paucimobilis EPA505 . Sequence analysis of PCR fragments generated from these isolates and of the GST gene amplified from DNA extracted from polycyclic aromatic hydrocarbon (PAH)-contaminated soil revealed a high degree of conservation, which may make the GST-encoding gene a potentially useful marker for PAH-degrading bacteria.

Appl Environ Microbiol, 1997 Aug, 63(8), 3111 - 8
Characterization of the sediment bacterial community in groundwater discharge zones of an alkaline fen: a seasonal study; Gsell TC et al.; The cell density, activity, and community structure of the bacterial community in wetland sediments were monitored over a 13-month period . The study was performed at Cedar Bog, an alkaline fen . The objective was to characterize the relationship between the sediment bacterial community in groundwater upwelling zones and the physical and chemical factors which might influence the community structure and activity . DNA, protein, and lipid synthesis were measured at three different upwelling zones by using {3H}thymidine, {14C}leucine, and {14C}glucose incorporation, respectively . The physiological status (apparent stress) of the consortium was assessed by comparing {14C}glucose incorporation into membrane and that into storage lipids . Bacterial cell density was determined by acridine orange direct counts, and gross bacterial community structure was determined by bisbenzimidazole-cesium chloride gradient analysis of total bacterial community DNA . Both seasonal and site-related covariation were observed in all estimates of bacterial biomass and activity . Growth rate estimates and cell density peaked in late July at 2.5 x 10(8) cells/g/day and 2.7 x 10(9) cells/g, respectively, and decreased in December to 2.0 x 10(7) cells/g/day and 1.5 x 10(9) cells/g, respectively . Across sites, membrane-to-storage-lipid ratios were generally highest in late spring and peaked in September for one site . Overall, the data indicate dynamic seasonal differences in sediment bacterial community activity and physiology, possibly in response to changing physical and chemical environmental factors which included the C/N/P ratios of the perfusing groundwater . By contrast, total cell numbers were rather constant, and community structure analysis indicated that the overall community structure was similar throughout the study.

Int Arch Allergy Immunol, 1997 Aug, 113(4), 424 - 31
Oral immunization with poly-(D,L-lactide-co-glycolide) and poly-(L-lactic acid) microspheres containing pneumotropic bacterial antigens; Kofler N et al.; Encouraged by recent findings showing the usefulness of nonreplicating antigen delivery systems in the induction ofmucosal immune responses, we investigated microspheres as a means to deliver LW 50020, an immunomodulator consisting of lysates of seven common respiratory pathogens . BALB/c mice were orally immunized with LW 50020 encapsulated into poly-(D,L-lactide-co-glycolide) (PLG) and poly-(L-lactic acid) (PLA) microspheres prepared by either a solvent-evaporation or a solvent-extraction double-emulsion technique . Particle uptake into intestinal Peyer's patches, induction of antibodies in sera and secretion of immunoglobulins by isolated Peyer's patches, lungs and spleen lymphocytes were investigated . Our results revealed size and surface characteristic-dependent uptake of microspheres into Peyer's patches . Microsphere translocation into Peyer's patches was efficient for 0.8-microm microspheres, but poor for 2.0-microm and surface-modified microspheres . We showed an enhanced immune response in the lungs and sera following oral immunization with 0.8-microm PLG solvent-evaporation microspheres . The immunomodulation was statistically significant as compared to free LW 50020 . In contrast, oral immunization with other preparations caused reduced or absent modulation of the immune response compared to 0.8-microm microspheres and free antigen . These findings indicate that microspheres displaying small particle sizes, rapid antigen release and high antigen content provide optimal tools to deliver orally applied antigens.

Clin Immunol Immunopathol, 1997 Aug, 84(2), 185 - 93
Bacterial DNA-induced NK cell IFN-gamma production is dependent on macrophage secretion of IL-12; Chace JH et al.; Bacterial DNA (bDNA) activates B cells and macrophages and can augment inflammatory responses by inducing release of proinflammatory cytokines . We found that bDNA stimulation of mouse spleen cells induced NK cell IFN-gamma production that was dependent upon the presence of unmethylated CpG motifs, and oligonucleotides with internal CpG motifs could also induce splenocytes to secrete IFN-gamma . The bDNA-induced IFN-gamma response was strictly macrophages dependent . While splenocytes from SCID mice secreted IFN-gamma in response to bDNA, depletion of macrophages eliminated this response . Additionally, purified NK cells did not respond to bDNA; however, addition of macrophages restored the NK cell IFN-gamma response . Coculture of NK cells with preactivated macrophages further increased bDNA-induced NK cell IFN-gamma production . Anti-IL-12 or IL-10 inhibited bDNA-induced IFN-gamma response . Treatment of purified macrophages with bDNA resulted in IL-12 secretion accompanied by an increase in IL-12 p40 mRNA level . Although isolated NK cells did not make IFN-gamma in response to bDNA, NK cells costimulated with IL-12 gained the ability to respond to bDNA . These experiments show that bDNA induces macrophage IL-12 production which, in turn, stimulates NK cell IFN-gamma production . Macrophage-derived IL-12 renders NK cells responsive to bDNA permitting an even greater IFN-gamma response to bDNA.

Blood, 1997 Aug 1, 90(3), 1246 - 54
Expression and intracellular localization of the human N-acetylmuramyl-L-alanine amidase, a bacterial cell wall-degrading enzyme; Hoijer MA et al.; N-acetylmuramyl-L-alanine amidase (NAMLAA) specifically degrades peptidoglycan, which is a major component of bacterial cell walls with strong inflammatory properties . For instance, peptidoglycan is capable of stimulating peripheral blood cells to release pro-inflammatory cytokines and is capable of inducing chronic arthritis in an animal model . In a previous study we found that degradation of peptidoglycan by purified NAMLAA reduced its inflammatory effects . To determine where NAMLAA is located in tissues, monoclonal antibodies against purified NAMLAA were produced for use in immunohistochemistry, immunoelectron microscopy, flow cytometric analysis, and Western blotting . The immunohistochemical studies showed NAMLAA-positive cells in human spleen, liver, arthritic synovial tissues, and lymph nodes . In flow cytometric studies of blood and bone marrow, neutrophilic and eosinophilic granulocytes proved to be positive . Monocytes were negative, although they do contain lysozyme, the other important peptidoglycan-degrading enzyme . However, mature macrophages obtained by bronchoalveolar lavage and subsequent selection based on autofluorescence did possess NAMLAA . In immunocytochemical staining of blood smears, thrombocytes were also positive for NAMLAA . Western blot analysis and immunoelectron microscopy of neutrophils and eosinophils showed that NAMLAA is located in azurophilic granules of neutrophils and in secretory vesicles and crystalloid-containing granules of eosinophils . Flow cytometric analysis of blood and bone marrow from different French-American-British-classified acute myeloid leukemia (AML) patients showed that AML-M2 myeloblasts were the first in the granulocyte maturation lineage that were positive for NAMLAA . The more immature AML, such as AML-M0 and AML-M1, did not express NAMLAA . CD15- and CD13-negative megakaryoblasts, corresponding to AML-M7, were also positive for NAMLAA . The expression pattern of NAMLAA in the myeloid lineage suggests that the monoclonal antibody AAA4, recognizing NAMLAA, is useful for discrimination between AML in the monocyte lineage and in the granulocyte lineage.

Infect Immun, 1997 Aug, 65(8), 3126 - 31
Inflammatory bowel disease: an immunity-mediated condition triggered by bacterial infection with Helicobacter hepaticus; Cahill RJ et al.; Inflammatory bowel disease (IBD) is thought to result from either an abnormal immunological response to enteric flora or a normal immunological response to a specific pathogen . No study to date has combined both factors . The present studies were carried out with an immunologically manipulated mouse model of IBD . Mice homozygous for the severe combined immunodeficiency (scid) mutation develop IBD with adoptive transfer of CD4+ T cells expressing high levels of CD45RB (CD45RB(high) CD4+ T cells) . These mice do not develop IBD in germfree conditions, implicating undefined intestinal flora in the pathogenesis of lesions . In controlled duplicate studies, the influence of a single murine pathogen, Helicobacter hepaticus, in combination with the abnormal immunological response on the development of IBD was assessed . The combination of H . hepaticus infection and CD45RB(high) CD4+ T-cell reconstitution resulted in severe disease expression similar to that observed in human IBD . This study demonstrates that IBD develops in mice as a consequence of an abnormal immune response in the presence of a single murine pathogen, H . hepaticus . The interaction of host immunity and a single pathogen in this murine system provides a novel model of human IBD, an immunity-mediated condition triggered by bacterial infection.

Clin Geriatr Med, 1997 Aug, 13(3), 565 - 73
Pressure ulcers . Managing bacterial colonization and infection; Stotts NA et al.; High levels of contamination are associated with delayed healing of pressure ulcers, and problems occur when surface contaminants invade the tissues and produce infection . This article addresses differentiating contamination from infection, identifying infection when it is present, and treating the patient with a contaminated or infected pressure ulcer . Systemic support for healing is discussed with a focus on oxygenation and nutrition . A comprehensive plan for the concomitant treatment of all factors contributing to pressure ulcer infection is recommended.

J Biol Chem, 1997 Jul 25, 272(30), 18595 - 601
Complex inhibition of OmpF and OmpC bacterial porins by polyamines; Iyer R et al.; The effects of four polyamines (putrescine, cadaverine, spermidine, and spermine) on the activity of bacterial porins OmpC and OmpF were investigated by electrophysiology . Membrane vesicles made from the outer membrane of Escherichia coli strains expressing only OmpC or OmpF were reconstituted into liposomes probed by patch clamp . The channel activity was recorded in control solutions and in the presence of increasing concentrations of a specific polyamine . In all cases, concentration- and voltage-dependent inhibitory effects were observed . They include both the suppression of channel openings and the enhancement of channel closures as well as the promotion of blocked or inactivated states . OmpF and OmpC, although highly homologous, have distinct sensitivities to modulation, especially by spermine . This compound inhibits OmpF in the nanomolar range, which is in agreement with its potency on eukaryotic channels . Putrescine was the least effective (upper millimolar range) and also had inhibitory effects qualitatively distinct from those exerted by the other polyamines . The compounds appear to bind to at least two distinct binding sites, one of which resides within the pore . The potencies to this site are lower when the polyamines are applied from the extracellular side than from the periplasmic side, suggesting an asymmetric binding site.

Biochemistry, 1997 Jul 22, 36(29), 9022 - 8
Mechanism-based inhibitors for the inactivation of the bacterial phosphotriesterase; Hong SB et al.; 1-Bromovinyl (I), Z-2-bromovinyl (II), 1,2-dibromoethyl (III), and a series of 4-(halomethyl)-2-nitrophenyl (IVa-c) diethyl phosphate esters were examined as substrates and mechanism-based inhibitors for the bacterial phosphotriesterase . All of these compounds were found to act as substrates for the enzyme . Inhibitor I rapidly inactivated the enzyme within 1 min, giving a partition ratio of 230 . The newly formed covalent adduct with inhibitor I was susceptible to hydrolysis at elevated values of pH and dissociation by NH2OH . Azide was not able to protect the enzyme from inactivation with inhibitor I, implying that the reactive species was not released into solution prior to the inactivation event . The reactive species was proposed to be either an acyl bromide or a ketene intermediate formed by the enzymatic hydrolysis of inhibitor I . Compounds II and III were shown to be relatively poor substrates of phosphotriesterase and they did not induce any significant inactivation of the enzyme . The inhibitor, 4-(bromomethyl)-2-nitrophenyl diethyl phosphate (IVa), was found to irreversibly inactivate the enzyme with a KI = 7.9 mM and kinact = 1 . 2 min-1 at pH 9.0 . There was no effect on the rate of inactivation upon the addition of the exogenous nucleophiles, azide, and NH2OH . The species responsible for the covalent modification of the enzyme by IVa was most likely a quinone methide formed by the elimination of bromide from the phenolic intermediate . NMR experiments demonstrated that the quinone methide did not accumulate in solution . The chloro (IVb) and fluoro (IVc) analogues did not inactivate the enzyme . These results suggest that the elimination of the halide ion from the phenolic intermediate largely determines the partition ratio for inactivation.

Gene, 1997 Jul 18, 194(1), 97 - 105
Human growth hormone receptor: cloning and expression of the full-length complementary DNA after site-directed inactivation of a cryptic bacterial promoter; Bieth E et al.; Growth hormone receptor is a cytokine-type receptor which is required for normal somatic growth and for numerous metabolic processes . Its complementary DNA (cDNA) has been isolated in various species leading to intensive studies to elucidate the mechanism of action of the growth hormone . However, serious difficulties have been reported in cloning in Escherichia coli, an intact full-length human cDNA . In this study, the cDNA is shown to contain a cryptic bacterial promoter driving inappropriate expression of a part of human growth hormone (hGH) receptor which is toxic for E . coli growth . Identification of this promoter and its inactivation by changing only one nucleotide led us to obtain stable bacterial clones containing a high copy number of full-length coding sequences . This molecular clone was used in a baculovirus/insect cell system to produce large amounts of glycosylated recombinant receptor . Binding studies with 125I-labelled hGH revealed an affinity constant of 2.8 x 10(9) M(-1), similar to that reported for the native liver receptor . This report described a general method of cloning which could be applied to similar unclonable cDNA fragments.

EMBO J, 1997 Jul 16, 16(14), 4295 - 301
Folding of a bacterial outer membrane protein during passage through the periplasm; Eppens EF et al.; The transport of bacterial outer membrane proteins to their destination might be either a one-step process via the contact zones between the inner and outer membrane or a two-step process, implicating a periplasmic intermediate that inserts into the membrane . Furthermore, folding might precede insertion or vice versa . To address these questions, we have made use of the known 3D-structure of the trimeric porin PhoE of Escherichia coli to engineer intramolecular disulfide bridges into this protein at positions that are not exposed to the periplasm once the protein is correctly assembled . The mutations did not interfere with the biogenesis of the protein, and disulfide bond formation appeared to be dependent on the periplasmic enzyme DsbA, which catalyzes disulfide bond formation in the periplasm . This proves that the protein passes through the periplasm on its way to the outer membrane . Furthermore, since the disulfide bonds create elements of tertiary structure within the mutant proteins, it appears that these proteins are at least partially folded before they insert into the outer membrane.

J Clin Invest, 1997 Jul 15, 100(2), 459 - 63
Stimulation of suppressive T cell responses by human but not bacterial 60-kD heat-shock protein in synovial fluid of patients with rheumatoid arthritis; van Roon JA et al.; In several animal models of rheumatoid arthritis (RA), T cell responses to self 60-kD heat-shock protein 60 (hsp60) protect against the induction of arthritis . The nature of this suppressive T cell activity induced by self hsp60 is not clear . In the present study, T cell responses to human (self) hsp60 in RA in terms of type 1 (T1) and type 2 (T2) T cell activity were assessed . The results show that human and not bacterial hsp60-reactive synovial fluid (SF) T cells of patients with RA proliferate in the presence of the T2 cell growth factor IL-4 . SF T cells stimulated with human hsp60 produced significantly lower amounts of IFN-gamma and higher amounts of IL-4 than SF T cells stimulated with bacterial hsp60 (P </= 0.002 and 0.05, respectively), and consequently a lower T1/T2 cell cytokine ratio was observed for human versus bacterial hsp60 (P </= 0.004) . Additionally, human and not mycobacterial hsp60-specific T cell lines suppressed TNF-alpha production . Together, our results suggest that human hsp60, as overexpressed in inflamed synovium of patients with RA, can contribute to suppression of arthritis by the stimulation of regulatory suppressive T cell activity.

J Clin Invest, 1997 Jul 15, 100(2), 296 - 309
Role of intestinal epithelial cells in the host secretory response to infection by invasive bacteria . Bacterial entry induces epithelial prostaglandin h synthase-2 expression and prostaglandin E2 and F2alpha production; Eckmann L et al.; Increased intestinal fluid secretion is a protective host response after enteric infection with invasive bacteria that is initiated within hours after infection, and is mediated by prostaglandin H synthase (PGHS) products in animal models of infection . Intestinal epithelial cells are the first host cells to become infected with invasive bacteria, which enter and pass through these cells to initiate mucosal, and ultimately systemic, infection . The present studies characterized the role of intestinal epithelial cells in the host secretory response after infection with invasive bacteria . Infection of cultured human intestinal epithelial cell lines with invasive bacteria, but not noninvasive bacteria, is shown to induce the expression of one of the rate-limiting enzymes for prostaglandin formation, PGHS-2, and the production of PGE2 and PGF2alpha . Furthermore, increased PGHS-2 expression was observed in intestinal epithelial cells in vivo after infection with invasive bacteria, using a human intestinal xenograft model in SCID mice . In support of the physiologic importance of epithelial PGHS-2 expression, supernatants from bacteria-infected intestinal epithelial cells were shown to increase chloride secretion in an in vitro model using polarized epithelial cells, and this activity was accounted for by PGE2 . These studies define a novel autocrine/paracrine function of mediators produced by intestinal epithelial cells in the rapid induction of increased fluid secretion in response to intestinal infection with invasive bacteria.

Biochemistry, 1997 Jul 15, 36(28), 8559 - 66
Temperature dependence of the Qy resonance Raman spectra of bacteriochlorophylls, the primary electron donor, and bacteriopheophytins in the bacterial photosynthetic reaction center; Cherepy NJ et al.; Qy-excited resonance Raman spectra of the accessory bacteriochlorophylls (B), the bacteriopheophytins (H), and the primary electron donor (P) in the bacterial photosynthetic reaction center (RC) of Rhodobacter sphaeroides have been obtained at 95 and 278 K . Frequency and intensity differences are observed in the low-frequency region of the P vibrational spectrum when the sample is cooled from 278 to 95 K . The B and H spectra exhibit minimal changes of frequencies and relative intensities as a function of temperature . The mode patterns in the Raman spectra of B and H differ very little from Raman spectra of the chromophores in vitro . The Raman scattering cross sections of B and H are 6-7 times larger than those for analogous modes of P at 278 K . The cross sections of B and of H are 3-4 times larger at 95 K than at 278 K, while the cross sections of P are approximately constant with temperature . The temperature dependence of the Raman cross sections for B and H suggests that pure dephasing arising from coupling to low-frequency solvent/protein modes is important in the damping of their excited states . The weak Raman cross sections of the special pair suggest that the excited state of P is damped by very rapid (<<30 fs) electronic relaxation processes . These resonance Raman spectra provide information for developing multimode vibronic models of the excited-state structure and dynamics of the chromophores in the RC.

Biochemistry, 1997 Jul 15, 36(28), 8548 - 58
Influence of iron-removal procedures on sequential electron transfer in photosynthetic bacterial reaction centers studied by transient EPR spectroscopy; Utschig LM et al.; Electron spin polarized electron paramagentic resonance (ESP EPR) spectra were obtained with deuterated iron-removed photosynthetic bacterial reaction centers (RCs) to specifically investigate the effect of the rate of primary charge separation, metal-site occupancy, and H-subunit content on the observed P865+QA- charge-separated state . Fe-removed and Zn-substituted RCs from Rb . sphaeroides R-26 were prepared by refined procedures, and specific electron transfer rates (kQ) from the intermediate acceptor H- to the primary acceptor QA of (200 ps)-1 vs (3-6 ns)-1 were observed . Correlation of the transient EPR and optical results shows that the observed slow kQ rate in Fe-removed RCs is H-subunit-independent, and, in some cases, independent of Fe-site occupancy as Zn2+ substitution does not ensure retention of the native kQ . In addition, shifts in the optical spectrum of P865 and differences in the high-field region of the Q-band ESP spectrum for Fe-removed RCs with slow kQ indicate possible structural changes near P865 . The experimental X-band and Q-band spin-polarized EPR spectra for deuterated Fe-removed RCs where kQ is at least 15-fold slower at room temperature than the (200 ps)-1 rate observed for native Fe-containing RCs have different relative amplitudes and small g-value shifts compared to the spectra of Zn-RCs which have a kQ unchanged from native RCs . These differences reflect the trends in polarization predicted from the sequential electron transfer polarization (SETP) model {Morris et al . (1995) J . Phys . Chem . 99, 3854-3866; Tang et al . (1996) Chem . Phys . Lett . 253, 293-298} . Thus, SETP modeling of these highly resolved ESP spectra obtained with well-characterized proteins will provide definitive information about any light-induced structural changes of P865, H, and QA that occur upon formation of the P865+QA- charge-separated state.

Gene, 1997 Jul 9, 193(2), 229 - 37
High-level production and purification of biologically active proteins from bacterial and mammalian cells using the tandem pGFLEX expression system; Manoharan HT et al.; Because of the complexities involved in the regulation of gene expression in Escherichia coli and mammalian cells, it is considered general practice to use different vectors for heterologous expression of recombinant proteins in these host systems . However, we have developed and report a shuttle vector system, pGFLEX, that provides high-level expression of recombinant glutathione S-transferase (GST) fusion proteins in E . coli and mammalian cells . pGFLEX contains the cytomegaloma virus (CMV) immediate-early promoter in tandem with the E . coli lacZpo system . The sequences involved in gene expression have been appropriately modified to enable high-level production of fusion proteins in either cell type . The pGFLEX expression system allows production of target proteins fused to either the N or C terminus of the GST pi protein and provides rapid purification of target proteins as either GST fusions or native proteins after cleavage with thrombin . The utility of this vector in identifying and purifying a component of a multi-protein complex is demonstrated with cyclin A . The pGFLEX expression system provides a singular and widely applicable tool for laboratory or industrial production of biologically active recombinant proteins in E . coli and mammalian cells.

Proc Natl Acad Sci U S A, 1997 Jul 8, 94(14), 7263 - 8
A model of excitation and adaptation in bacterial chemotaxis; Spiro PA et al.; Bacterial chemotaxis is widely studied because of its accessibility and because it incorporates processes that are important in a number of sensory systems: signal transduction, excitation, adaptation, and a change in behavior, all in response to stimuli . Quantitative data on the change in behavior are available for this system, and the major biochemical steps in the signal transduction/processing pathway have been identified . We have incorporated recent biochemical data into a mathematical model that can reproduce many of the major features of the intracellular response, including the change in the level of chemotactic proteins to step and ramp stimuli such as those used in experimental protocols . The interaction of the chemotactic proteins with the motor is not modeled, but we can estimate the degree of cooperativity needed to produce the observed gain under the assumption that the chemotactic proteins interact directly with the motor proteins.

Kansenshogaku Zasshi, 1997 Jul, 71(7), 680 - 3
{A case of bacterial meningitis induced by strongyloidiasis}; Higashiyama Y et al.; A 75-year-old female with diabetes mellitus, who was born and lived in West north Kyusyu, was admitted to our hospital, because of unconsciousness and loss of appetite . The physical examination showed neck stiffness and a high fever . The laboratory data showed accentuation of inflammatory reaction and azotemia and positive HTLV-1 antibody . The spinal fluid showed increase of cell count and amount of protein . A stool and sputum smear revealed rhabditis form larvae of the nematode . Antibiotics and ivermectin were administered for the bacterial meningitis and hyperinfection of the strongyloides, respectively . Consequently, meningitis and strongyloidiasis improved . It was considered that the patient was infected with strongyloides from her husband who serve in the army during World-War II, and hyperinfection of strongyloides resulted from the immunosuppressive state of diabetes mellitus . Ivermectin, and anti-strongyloides agent, was effective, and no side effects were seen . However, the therapeutic resistance in this case was associated with the positive HTLV-1 antibody.

Mol Microbiol, 1997 Jul, 25(2), 295 - 302
The use of flash photolysis for a high-resolution temporal and spatial analysis of bacterial chemotactic behaviour: CheZ is not always necessary for chemotaxis; Dowd JP et al.; The purpose of this work was to develop a high-resolution analysis of behaviour as an assay of the physiological consequences of mutations in the che genes and also to examine the role of CheZ in chemotaxis . Recent advances in flash photolysis have made it possible to expose cells to an unstable chemical gradient created by a square-wave increase in attractant concentration . The response of individual cells can be tracked in the order of milliseconds using real-time motion analysis . The tumble frequency of wild-type Escherichia coli exposed to photoreleased aspartate falls very quickly to smooth-swimming levels, and the swimming speed of these cells rises . As a consequence of these behavioural changes, there is an increase in the number of bacteria present in the centre of the flashed area, that is the bacteria's response to the transient gradient generated by flash photolysis was to swim into the centre of the flash area . This allowed the rapid quantitative measurement of chemotaxis . Deletion of various che genes resulted in predictable changes in chemotactic behaviour . cheZ null mutants are non-chemotactic when measured by classical techniques but demonstrate a definite chemotactic response to photoreleased attractant.

APMIS, 1997 Jul, 105(7), 531 - 6
Detection of serum interferon-alpha by dissociation-enhanced lanthanide fluoroimmunoassay . Studies of patients with acute viral and bacterial infections; Ronnblom LE et al.; A sensitive dissociation-enhanced lanthanide fluoroimmunoassay (DELFIA) was evaluated for ability to detect interferon-alpha (IFN-alpha) in serum of patients with acute infectious disease of less than one week's duration and a fever of > 38 degrees C . None of 36 patients with confirmed or probable bacterial disease was IFN-alpha positive . In contrast, 13/26 patients with viral infections had detectable levels of IFN-alpha in serum, all clearly positive (> or = 10 U/ml) . The IFN-alpha positive serum samples were obtained early after onset of clinical disease, after a mean of 2.4 days . The IFN-alpha positive samples were obtained from 10 of the 12 patients with influenza or flu-like infection, and 3 of the 5 patients with varicella or herpes zoster . The IFN-alpha negative patients with viral disease (n = 9) included five patients with mononucleosis . The DELFIA should be useful in further studies of the value of IFN-alpha determinations in the identification of acute viral infections.

Genome Res, 1997 Jul, 7(7), 736 - 46
An approximately 1.2-Mb bacterial artificial chromosome contig refines the genetic and physical maps of the lurcher locus on mouse chromosome 6; De Jager PL et al.; Lurcher (Lc) is a semidominant mouse mutant that displays a characteristic ataxia in the heterozygous state beginning in the third postnatal week . This symptom results from a neurodegenerative event in the cerebellum: There is a catastrophic loss of Purkinje cells in the heterozygote animal between postnatal days 10 and 15 . In an effort to identify the genetic lesion borne by Lc mice, we initiated a cloning project based on the position of the Lc mutation on mouse chromosome 6 . We have extended our previous analysis of the genomic segment containing the Lc locus by isolating a set of stable and manipulable genomic clones called bacterial artificial chromosomes (BACs) that cover this region of mouse chromosome 6 . These clones provided a good substrate for the isolation of markers that were used to refine the physical map of the locus . Furthermore, 20 of these markers were mapped onto our (B6CBACa-AW-J/A-Lc x CAST/Ei)F1 x B6CBACa-AW-J/A backcross, refining the genetic map and identifying two nonrecombinant markers (D6Rck354 and D6Rck355) . These two markers, in conjunction with the closest flanking markers, were used to identify a 110-kb genomic segment that contains all four markers and hence contains the Lc locus . This small genomic segment, covered by multiple BACs, sets the stage for the final effort of this project-the identification of transcripts and of the mutation within the Lc locus.

Eur J Anaesthesiol, 1997 Jul, 14(4), 428 - 31
Antiseptic-impregnated central venous catheters reduce the incidence of bacterial colonization and associated infection in immunocompromised transplant patients; George SJ et al.; The incidence of bacterial colonization of central venous catheters using a standard polyurethane catheter was compared with that using an antiseptic (silver sulphadiazine and chlorhexidine) impregnated catheter in a group of patients with thoracic organ transplantation . Colonization was reduced from 25 of 35 standard catheters to 10 of 44 study catheters (P < 0.002), a 68% reduction . Similarly, the incidence of concomitant infection, by the same organism at another site was reduced from 10 of 35 standard catheters to 4 of 44 study catheters (P < 0.03), a 63% reduction.

JPEN J Parenter Enteral Nutr, 1997 Jul-Aug, 21(4), 208 - 14
Glutamine-enriched enteral diet enhances bacterial clearance in protected bacterial peritonitis, regardless of glutamine form; Furukawa S et al.; BACKGROUND: The effects of glutamine (Gln)-enriched enteral diets on bacterial clearance were investigated in a rat protracted peritonitis model . The effects of the Gln form, peptide-based vs free amino acid-based, were also compared . METHODS: Twenty-three rats underwent gastrostomy . An osmotic pump was implanted in the peritoneal cavity . The rats received a continuous intragastric infusion of one of three diets: Gln-depleted (Gln 0), Gln-enriched with the Gln in free amino acid form (Gln F), or Gln-enriched with the Gln in oligopeptide form (Gln P) . The three formulas were isocaloric and isonitrogenous . The pumps delivered a continuous infusion of Escherichia coli, starting at 48 hours after implantation, for 24 hours . Then, the animals were killed . RESULTS: Bacterial numbers in peritoneal lavaged fluid (PLF) and the liver were significantly lower in the Gln P and Gln F groups than in the Gln 0 group . The bacterial number in PLF correlated with that in the liver . Neither the number nor the population of peritoneal exudative cells differed among groups . Plasma levels of proline, alanine and citrulline were significantly higher in the Gln P and Gln F groups than in the Gln 0 group . Both Gln supplemented groups showed significantly greater villous height, crypt depth, and numbers of mitoses per crypt in the small intestine than the Gln 0 group . CONCLUSIONS: Supplemental Gln enhances peritoneal and hepatic bacterial clearance, regardless of Gln form . Gln-enriched may be more beneficial than Gln-depleted enteral diets in peritonitis.

J Reprod Med, 1997 Jul, 42(7), 455 - 8
Ruptured bacterial intracranial aneurysm in pregnancy . A case report; Powell S et al.; BACKGROUND: Rupture of a documented infectious cerebral aneurysm is a rare complication of infectious endocarditis, with a high morbidity and mortality rate . The only previously reported case was associated with maternal and neonatal mortality . No known report exists of a ruptured bacterial intracranial aneurysm complicating an ongoing pregnancy with maternal or fetal survival . CASE: A 38-year-old, white woman, gravida 9, para 4, at 18 weeks' gestation, developed infectious endocarditis with peripheral and cerebral emboli secondary to intravenous drug abuse, causing renal failure and cortical strokes . She required hemodialysis and also suffered a subarachnoid hemorrhage due to rupture of cerebral bacterial aneurysms . A team approach to her care was necessary . At 28 weeks' gestation she delivered by cesarean section for abruptio placentae . Both the mother and neonate recovered . CONCLUSION: Rupture of mycotic aneurysms can be catastrophic and is often managed surgically . The patient described here was severely affected, and though indicated, surgical intervention was not possible . An aggressive team approach provided a good maternal and fetal outcome.

Eur J Biochem, 1997 Jul 1, 247(1), 425 - 31
The signal transducer gp130--bacterial expression, refolding and properties of the carboxy-terminal domain of the cytokine-binding module; Muller-Newen G et al.; Gp130 is the signal transducing receptor subunit of the so-called interleukin-6-type cytokines . This transmembrane protein is a member of the cytokine-receptor superfamily predicted to consist of six fibronectin-type-III-like domains in its extracellular part . The second and the third domain constitute the so-called cytokine-binding module . Domain 2 is characterized by a set of four conserved Cys residues, domain 3 by a conserved WSXWS motif . As a first approach to a more detailed characterization of the cytokine-binding domains of human gp130, we have expressed in Escherichia coli two forms of domain 3 differing in length . Both proteins were purified and refolded in a single step applying size-exclusion chromatography . According to the rotational correlation times deduced from fluorescence anisotropy decay, they do not form aggregates . CD and fluorescence spectroscopy were used to study thermal unfolding and denaturation by guanidinium hydrochloride . It was shown that N- and C-terminal extension by residues of the adjacent hinge regions substantially increase the thermal stability of the domain, which is conceivable from a molecular model . These results are the basis for further structural investigation by NMR spectroscopy.

J Struct Biol, 1997 Jul, 119(2), 212 - 21
Hydration scanning tunneling microscopy of DNA and a bacterial surface protein; Heim M et al.; Hydration scanning tunneling microscopy is based on the electrical conductivity of molecularly thin water layers which adsorb to the sample surfaces in a humid atmosphere . It allows reliable imaging of biological specimens and even insulators, provided they are hydrophilic . Here, we present results obtained with linearized plasmid DNA on mica and a bacterial surface protein layer (the HPI layer) . A width of 3 nm was measured for the DNA molecules and a quasi-periodic structure along the molecules with a repeat distance of about 5 nm was observed . We show that-depending on the tunneling voltage-there are two different imaging modes for the DNA samples: at higher voltages, real tunneling or field emission is responsible for the charge transfer between tip and sample . In contrast, at lower voltages we found indications of a water meniscus between tip and surface . The HPI layer, however, seems to be imaged at most voltages without a water meniscus.

Trends Microbiol, 1997 Jul, 5(7), 282 - 8
Rho proteins: targets for bacterial toxins; Aktories K; GTP-binding proteins of the Rho family are regulators of the actin cytoskeleton and molecular switches in various signal transduction pathways . The Rho proteins are targets for bacterial protein toxins that either inactivate GTPases by ADP-ribosylation or glucosylation, or activate them by deamidation . Rho proteins play essential roles in host cell invasion by bacteria.

Arthritis Rheum, 1997 Jul, 40(7), 1250 - 6
Usefulness of procalcitonin for differentiation between activity of systemic autoimmune disease (systemic lupus erythematosus/systemic antineutrophil cytoplasmic antibody-associated vasculitis) and invasive bacterial infection; Eberhard OK et al.; OBJECTIVE: To investigate whether the determination of serum procalcitonin (PCT) in systemic autoimmune disease will help to discriminate invasive infection from highly active underlying disease . METHODS: Three hundred ninety-seven serum samples, from 18 patients with systemic lupus erythematosus (SLE) and 35 patients with systemic antineutrophil cytoplasmic antibody-associated vasculitis (AAV), were analyzed . Clinical disease activity was assessed by the Systemic Lupus Activity Measure in SLE patients and by the Birmingham Vasculitis Activity Score in AAV patients . Procalcitonin concentrations were determined in parallel with concentrations of neopterin, interleukin-6 (IL-6), and C-reactive protein (CRP) . Additionally, serum creatinine values were obtained . RESULTS: In 321 of the 324 samples from the 42 patients with autoimmune disease but without systemic infection, serum PCT levels were within the normal range (i.e., <0.5 ng/ml), whereas the values for neopterin, IL-6, and CRP were elevated in patients with active underlying disease . All 16 systemic infections occurred in 11 patients with AAV, and were associated with PCT levels that were markedly elevated, to a mean +/- SD of 1.93 +/- 1.19 ng/ml . No correlation between the degree of renal impairment and PCT concentrations was seen . CONCLUSION: PCT may serve as a useful marker for the detection of systemic bacterial infection in patients with systemic autoimmune disease.

J Mol Evol, 1997 Jul, 45(1), 107 - 14
A protein related to eucaryal and bacterial DNA-motor proteins in the hyperthermophilic archaeon Sulfolobus acidocaldarius; Elie C et al.; We have isolated a new gene encoding a putative 103-kDa protein from the hyperthermophilic archaeon Sulfolobus acidocaldarius . Analysis of the deduced amino-acid sequence shows an extended central domain, predicted to form coiled-coil structures, and two terminal domains that display purine NTPase motifs . These features are reminiscent of mechanochemical motor proteins which use the energy of ATP hydrolysis to move specific cellular components . Comparative analysis of the amino-acid sequence of the terminal domains and predicted structural organization of this putative purine NTPase show that it is related both to eucaryal proteins from the "SMC family" involved in the condensation of chromosomes and to several bacterial and eucaryal proteins involved in DNA recombination/repair . Further analyses revealed that these proteins are all members of the so called "UvrA-related NTP-binding proteins superfamily" and form a large subgroup of motor-like NTPases involved in different DNA processing mechanisms . The presence of such protein in Archaea, Bacteria, and Eucarya suggests an early origin of DNA-motor proteins that could have emerged and diversified by domain shuffling.

Biophys J, 1997 Jul, 73(1), 367 - 81
Kinetics of H+ ion binding by the P+QA-state of bacterial photosynthetic reaction centers: rate limitation within the protein; Maroti P et al.; The kinetics of flash-induced H+ ion binding by isolated reaction centers (RCs) of Rhodobacter sphaeroides, strain R-26, were measured, using pH indicators and conductimetry, in the presence of terbutryn to block electron transfer between the primary and secondary quinones (QA and QB), and in the absence of exogenous electron donors to the oxidized primary donor, P+, i.e., the P+QA-state . Under these conditions, proton binding by RCs is to the protein rather than to any of the cofactors . After light activation to form P+QA-, the kinetics of proton binding were monoexponential at all pH values studied . At neutral pH, the apparent bimolecular rate constant was close to the diffusional limit for proton transfer in aqueous solution (approximately 10(11) M-1 s-1), but increased significantly in the alkaline pH range (e.g., 2 x 10(13) M-1 s-1 at pH 10) . The average slope of the pH dependence was -0.4 instead of -1.0, as might be expected for a H+ diffusion-controlled process . High activation energy (0.54 eV at pH 8.0) and weak viscosity dependence showed that H+ ion uptake by RCs is not limited by diffusion . The salt dependence of the H+ ion binding rate and the pK values of the protonatable amino acid residues of the reaction center implicated surface charge influences, and Gouy-Chapman theory provided a workable description of the ionic effects as arising from modulation of the pH at the surface of the RC . Incubation in D2O caused small increases in the pKs of the protonatable groups and a small, pH (pD)-dependent slowing of the binding rate . The salt, pH, temperature, viscosity, and D2O dependences of the proton uptake by RCs in the P+QA- state were accounted for by three considerations: 1) parallel pathways of H+ delivery to the RC, contributing to the observed (net) H+ disappearance; 2) rate limitation of the protonation of target groups within the protein by conformational dynamics; and 3) electrostatic influences of charged groups in the protein, via the surface pH.

FEBS Lett, 1997 Jun 30, 410(2-3), 319 - 23
Expressional downregulation of neuronal-type NO synthase I in guinea pig skeletal muscle in response to bacterial lipopolysaccharide; Gath I et al.; We have investigated the expression of neuronal-type NO synthase I (NOS I) and inducible-type NOS II in guinea pig skeletal muscle (diaphragm) . Expression of NOS I mRNA and protein was highest in muscle of specific pathogen-free animals, lower in normally bred animals, and lowest in lipopolysaccharide (LPS)-treated animals . NOS II mRNA and protein levels were highest in muscle of LPS-treated animals . Elevated NOS activity in muscle from LPS-treated animals was less susceptible to the NOS I-selective inhibitor N(G)-nitro-L-arginine . Expressional downregulation of NOS I in sepsis may have implications for contractile function of skeletal muscle.

J Biol Chem, 1997 Jun 27, 272(26), 16445 - 52
Phosphatidylinositol 3-kinase-dependent activation of protein kinase C-zeta in bacterial lipopolysaccharide-treated human monocytes; Herrera-Velit P et al.; The isoform identity of activated protein kinase C (PKC) and its regulation were investigated in bacterial lipopolysaccharide (LPS)-treated human monocytes . Resolution of detergent-soluble lysates prepared from LPS-treated, peripheral blood monocytes using Mono Q anion-exchange chromatography revealed two principal peaks of myelin basic protein kinase activity . Immunoblotting and immunoprecipitation with isoform-specific anti-PKC antibodies showed that the major and latest eluting peak is accounted for by PKC-zeta . In addition to primary monocytes, activation of PKC-zeta in response to LPS was also observed in the human promonocytic cell lines, U937 and THP-1 . Consistent with its identity as PKC-zeta, the kinase did not depend upon the presence of lipids, Ca2+, or diacylglycerol for activity . In addition, the kinase phosphorylates peptide epsilon and myelin basic protein with equal efficiency but phosphorylates Kemptide and protamine sulfate poorly . Translocation of PKC-zeta from the cytosolic to the particulate membrane fraction upon exposure of monocytes to LPS provided further evidence for activation of the kinase . Preincubation of monocytes with the phosphatidylinositol 3-kinase (PI 3-kinase) inhibitors, wortmannin or LY294002, abrogated LPS-induced activation of PKC-zeta . Furthermore, activation of PKC-zeta failed to occur in U937 cells transfected with a dominant negative mutant of the p85 subunit of PI 3-kinase . PKC-zeta activity was also observed to be enhanced in vitro by the addition of phosphatidylinositol 3,4,5P3 . These findings are consistent with a model in which PKC-zeta is activated downstream of PI 3-kinase in monocytes in response to LPS.

Biochemistry, 1997 Jun 10, 36(23), 6885 - 95
Structures of the reduced and mercury-bound forms of MerP, the periplasmic protein from the bacterial mercury detoxification system; Steele RA et al.; Bacteria carrying plasmids with the mer operon, which encodes the proteins responsible for the bacterial mercury detoxification system, have the ability to transport Hg(II) across the cell membrane into the cytoplasm where it is reduced to Hg(0) . This is significant because metallic mercury is relatively nontoxic and volatile and thus can be passively eliminated . The structures of the reduced and mercury-bound forms of merP, the periplasmic protein, which binds Hg(II) and transfers it to the membrane transport protein merT, have been determined in aqueous solution by multidimensional NMR spectroscopy . The 72-residue merP protein has a betaalpha betabeta alphabeta fold with the two alpha helices overlaying a four-strand antiparallel beta sheet . Structural differences between the reduced and mercury-bound forms of merP are localized to the metal binding loop containing the consensus sequence GMTCXXC . The structure of the mercury-bound form of merP shows that Hg(II) is bicoordinate with the Cys side chain ligands, and this is confirmed by the chemical shift frequency of the 199Hg resonance.

FEBS Lett, 1997 Jun 9, 409(2), 269 - 72
Bacterial expression and purification of biologically active mouse c-Fos proteins by selective codon optimization; Deng T; A simple strategy using selective codon optimization was devised to express mouse c-Fos protein in high levels in E . coli . Ten arginine codons located in the basic region were optimized to achieve high levels of protein expression . The c-Fos protein was purified to near homogeneity and was demonstrated to be biologically active by assaying its several biological activities.

Biochem Biophys Res Commun, 1997 Jun 9, 235(1), 64 - 8
Molecular cloning of a rat 49-kDa TBP-interacting protein (TIP49) that is highly homologous to the bacterial RuvB; Kanemaki M et al.; TBP as a central component in transcriptional regulation can form complexes with various regulatory factors . Using histidine-tagged TBP for affinity-purification of TBP-bound proteins, we isolated a 49-kD protein termed TBP-interacting protein 49 (TIP49) from rat liver nuclear extracts . We cloned the entire cDNA of TIP49 encoding a novel polypeptide of 456 amino acids, and thereafter established an FM3A cell line that constitutively expressed an epitope-tagged TBP . Immunoprecipitation analysis of the cell extracts indicated that TIP49 and TBP were present in an identical complex . Interestingly, the amino acid sequence of TIP49 exhibited high similarity to those sequences of the RuvB bacterial recombination factors which direct branch migration of the Holliday junction and contain the Walker A and B motifs responsible for ATP binding and ATP hydrolysis . These findings suggest that TIP49 is a putative ATP-dependent DNA helicase.

Eur J Pharmacol, 1997 Jun 5, 328(1), 69 - 73
Attenuation of endothelium-dependent hyperpolarizing factor by bacterial lipopolysaccharides; Kristof AS et al.; Endothelium-dependent hyperpolarizing factor (EDHF) is an important contributor to agonist-induced vascular dilation . Recent studies suggest that bacterial lipopolysaccharides attenuate endothelium-dependent dilation . Whether or not this effect is mediated through inhibition of EDHF is not known . We studied the in vitro influence of Escherichia coli lipopolysaccharides on endothelium-dependent smooth muscle dilation and hyperpolarization in porcine coronary arteries . Endothelium-intact porcine coronary arterial rings were examined after 20 h of incubation with either saline or E . coli lipopolysaccharides (100 microg/ml) . Endothelium-dependent dilation elicited by increasing concentrations of bradykinin was significantly attenuated by lipopolysaccharides . Baseline values of smooth muscle membrane potential were not influenced by lipopolysaccharides . However, lipopolysaccharides significantly attenuated bradykinin-induced smooth muscle membrane hyperpolarization . Our results suggest that attenuation of EDHF is an important mechanism through which lipopolysaccharides influence vascular dilation in severe sepsis.

Contraception, 1997 Jun, 55(6), 355 - 8
Contraceptive use in women with bacterial vaginosis; Shoubnikova M et al.; The aim of the study was to investigate if bacterial vaginosis (BV) is associated with use of specific contraceptives . Women at family planning and youth clinics (n = 956), among whom 131 had BV, were subjects for structured in-depth interviews including current and previous contraceptive use . Variables measuring sexual risk-taking were ascertained . Current users of contraceptives were compared with non-users . Both oral contraceptive (OC) and condom use showed a significant protective effect against BV, adjusted for possible confounders (odds ratios were 0.4 and 0.3, respectively) . Intrauterine device use (IUD) showed no association with BV . Women with BV had less often used any contraceptives, including condom, at their sexual debut than the women in the comparison group . In this study, OC and condom use seemed to exert a protective effect against BV, whereas no effect for IUD use was foundPIP: To determine whether bacterial vaginosis (BV) is associated with use of specific contraceptive methods, 956 women from family planning and youth clinics at 3 Swedish hospitals were enrolled in a cohort study . 131 women had at least 3 of the 4 clinical signs of BV: a homogenous gray vaginal discharge, a vaginal pH of 4.7, a positive amine test, and the presence of "clue" cells . Age at first intercourse was 16 years among those with and without BV; however, 8.4% of women with BV, compared with only 1.7% of controls, had had more than 1 sex partner in the last 6 months . Other factors associated with BV were more than 10 lifetime sex partners, non-use of contraception at first intercourse, a history of sexual abuse, an induced abortion, smoking, and alcohol consumption . After adjustment for sexual risk-taking, there was a significant negative association between BV and oral contraceptive (OC) use (odds ratio {OR}, 0.4; 95% confidence interval {CI}, 0.2-0.8) . There was also a significant negative association with condom use (OR, 0.3; 95% CI, 0.1-0.9) . There was no association between BV and IUD use, before or after adjustment for confounding factors . Insufficient numbers of diaphragm or spermicide users were available for analysis . The finding of an apparently protective effect against BV of OCs and condoms lacks a biological explanation at present, although it is speculated that OC use increases the glycogen content of vaginal epithelial cells, in turn inhibiting the in vitro growth of certain bacteria .

Korean J Parasitol, 1997 Jun, 35(2), 127 - 33
{Bacterial endosymbiosis within the cytoplasm of Acanthamoeba lugdunensis isolated from a contact lens storage case}; Chung DI et al.; Transmission electron microscopy of an Acanthamoeba isolate (KA/L5) from a contact lens case revealed bacterial endosymbionts within cytoplasm of the amoebae . The Acanthamoeba isolate belonged to the morphological group II . Based on the polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) of 18S ribosomal RNA coding DNA (rDNA), the isolate was identified as A . lugdunensis . Strain typing by isoenzyme analysis using isoelectric focusing (IEF) and mitochondrial (Mt) DNA RFLP revealed that the isolate was closely related with KA/L1, the most predominant type of isolates from contact lens storage cases, KA/E2, a clinical isolate, KA/W4, previously reported to host endosymbionts, and L3a strains of A . lugdunensis . The endosymbionts were similar to those of KA/W4 in aspects that they were randomly distributed in both trophozoites and cysts, and were rod-shaped bacteria measuring approximately 1.38 x 0.50 microns . But the number of endosymbionts per amoeba was significantly lower than that of KA/W4 . They were neither limited by phagosomal membranes nor included in lacunaelike structure.

Curr Opin Neurol, 1997 Jun, 10(3), 254 - 9
Brain injury in bacterial meningitis: therapeutic implications; Pfister HW et al.; Recent in-vitro studies have improved our understanding of how bacteria interact with cerebral endothelial cells and cross the blood-brain barrier . Several animal studies using rat and rabbit models of bacterial meningitis have revealed mediators of inflammation that are believed to play a key role in secondary brain damage, including reactive oxygen species, nitric oxide, and excitatory amino acids . Treatment with free-radical scavengers, nitric oxide synthase inhibitors, excitatory amino acid antagonists, as well as the anti-inflammatory cytokine interleukin-10 was beneficial in experimental bacterial meningitis . Apart from dexamethasone these agents hold major promise for the adjunctive therapy of bacterial meningitis in clinical practice.

FEMS Immunol Med Microbiol, 1997 Jun, 18(2), 133 - 8
Non-seasonal viral and bacterial episode of diarrhoea in the Jordan Valley, West of Jordan; Meqdam MM et al.; A non-seasonal diarrhoeal episode in the Jordan Valley occurred over a 2-month period, during which no traditional enteropathogens were detected by the health authority laboratories . A total of 17 diarrhoeal stool specimens from infants, young children and adults were randomly collected and delivered to our laboratories to investigate the presence of unusual aetiological agents . Stools were examined for parasites, ova, viruses and cultured for bacterial pathogens . A multiplex polymerase chain reaction was developed to investigate the involvement of diarrhoeagenic Escherichia coli in this episode . Recognised pathogenic organisms were detected in 8 out of 17 of the diarrhoeatic patients, one patient of whom had a mixed infection with two agents . Rotavirus, enteroinvasive E . coli (EIEC), enteropathogenic E . coli (EPEC), and enterotoxigenic E . coli (ETEC) were found to be associated with the diarrhoea . EIEC was the most common enteropathogen detected (4 out of 17) followed by rotavirus (3 out of 17) . One of the EIEC isolates detected in one patient was associated with rotavirus . The clinical features of the diarrhoeatic patients were remarkably similar, regardless of aetiology . This study reveals the identity of pathogenic agents that are not detected by traditional methods employed by the health authority laboratories, which emphasise the urgent need for developing the current diagnostic techniques.

Am J Obstet Gynecol, 1997 Jun, 176(6), 1270 - 5; discussion 1275-7
Vaginal pH as a marker for bacterial pathogens and menopausal status; Caillouette JC et al.; OBJECTIVE: Our purpose was to confirm the elevation of vaginal pH expected in patients with bacterial pathogens in premenopausal women and to examine the relationship of serum follicle-stimulating hormone and estradiol levels to vaginal pH in menopausal patients without and with hormone replacement therapy . STUDY DESIGN: Vaginal pH was determined by phenaphthazine (Nitrazine) pH paper in 253 patients seen in a solo private practice for routine speculum examination . None of the patients were pregnant . Measurements were made of serum levels of follicle-stimulating hormone and estradiol for 172 patients and vaginal cultures were taken from 82 patients . Vaginal pH was correlated with vaginal cultures and serum follicle-stimulating hormone and estradiol levels by use of statistical analysis . RESULTS: Vaginal pH was elevated in all premenopausal patients with documented bacterial pathogens . Serum estradiol levels showed an inverse and serum follicle-stimulating hormone levels a direct statistical correlation with vaginal pH in menopausal patients . CONCLUSIONS: Measurement of vaginal pH is useful, effective, and inexpensive for screening purposes . A vaginal pH of 4.5 is consistent with a premenopausal serum estradiol level and the absence of bacterial pathogens . An elevated vaginal pH in the 5.0 to 6.5 range suggests a diagnosis of either bacterial pathogens or decreased serum estradiol . In patients with an elevated pH, vaginal culture should establish the diagnosis . In the absence of bacterial pathogens, a vaginal pH of 6.0 to 7.5 is strongly suggestive of menopause . Titration of estradiol level by vaginal pH during estrogen replacement therapy may help menopausal women avoid side effects or cessation of therapy.

Biol Pharm Bull, 1997 Jun, 20(6), 711 - 3
Cloning and bacterial expression of a gene encoding ribosome-inactivating proteins, karasurin-A and karasurin-C, from Trichosanthes kirilowii var . japonica; Mizukami H et al.; A genomic DNA clone of karasurin was isolated using the polymerase chain reaction from Trichosanthes kirilowii var . japonica (Cucurbitaceae) . The amino acid sequence deduced from the nucleotide sequence was consistent with previously reported sequences of karasurin-A and karasurin-C except for a putative signal peptide and extra amino acids at the C-terminus, neither of which is present in the natural protein . Recombinant karasurin was synthesized in Escherichia coli, in which the cloned karasurin gene was expressed under the control of the trc promoter.

J Hepatol, 1997 Jun, 26(6), 1372 - 8
Intestinal bacterial overgrowth and bacterial translocation in cirrhotic rats with ascites; Guarner C et al.; BACKGROUND/AIMS: Translocation of indigenous bacteria from the gut lumen of cirrhotic animals to mesenteric lymph nodes appears to be an important step in the pathogenesis of spontaneous bacterial peritonitis . However, the sequence of events leading to translocation remains unclear . One of the most predictable risk factors for translocation is overgrowth of gut bacterial flora . The present study was designed to compare the intestinal aerobic bacterial flora of cecal stools at the time of sacrifice between cirrhotic and normal rats and to evaluate the role of intestinal aerobic bacterial overgrowth in bacterial translocation in cirrhotic rats . METHODS: Thirty-five male Sprague-Dawley rats with carbon tetrachloride-induced cirrhosis and ascites and 10 normal rats were included in this study . Cirrhotic rats were sacrificed when ill and samples of ascitic fluid, mesenteric lymph nodes and cecal stool were taken for detecting quantitatively aerobic bacteria . RESULTS: Total intestinal aerobic bacterial count in cecal stool at the time of sacrifice was significantly increased in cirrhotic rats with bacterial translocation with or without spontaneous bacterial peritonitis compared to cirrhotic rats without bacterial translocation (p<0.001 and p<0.001, respectively) and to normal rats (p<0.001 and p<0.001, respectively) . Of the 42 species of bacteria translocating to the mesenteric lymph nodes, 41 (97.6%) were found in supranormal numbers in the stool at the time of sacrifice . CONCLUSIONS: Carbon tetrachloride-induced cirrhotic rats with bacterial translocation have increased total intestinal aerobic bacteria count, and intestinal bacterial overgrowth appears to play an important role in bacterial translocation in this experimental model of cirrhosis in rats.

Pharm Acta Helv, 1997 Jun, 72(3), 139 - 43
Oligonucleotide-directed mutagenesis and subsequent expression of the corresponding recombinant proteins without changing the bacterial vector system; Michael M et al.; A new bacterial vector was constructed that combines the attractive features of gene fusion vectors and phagemids . A gene of interest cloned into this new vector can either be expressed as fusion protein or be prepared as single-stranded template DNA within the same system . Thus, time consuming subcloning procedures changing the bacterial vector according to the required method are avoided . As an example sequencing, expression and subsequent purification of site-directed mutants of herpes simplex virus type 1 thymidine kinase are discussed.

Scand J Immunol, 1997 Jun, 45(6), 645 - 54
Retrovirally induced mouse anti-TCR monoclonals can synergize the in vitro proliferative T cell response to bacterial superantigens; Dehghanpisheh K et al.; Antibodies directed against the beta chain of the T-cell receptor (TCR) have been detected in animals and in humans in a number of distinct immune states that do not involve direct immunization with either T cells or TCR epitopes . When C57B1/6 mice are infected experimentally with the LP-BM5 retrovirus mixture they produce increased titres of autoantibodies directed against TCR V beta complementarity determining region 1 (CDR1) epitopes . Here, the authors utilized hybridoma technology to isolate monoclonal immunoglobulin (Ig)M antibodies (MoAbs) that arose at the peak of infection . The authors characterized the binding specificity tested using synthetic peptides modelling the CDR1 segments of 24 distinct V beta gene products and determined the VH gene usage by two such monoclonals . One binds to a restricted set of TCR V beta CDR1 peptides, and the second reacts with approximately half of the CDR1 peptide homologues . These MoAbs are specific for T-cell receptor beta chains and do not bind to immunoglobulin light chains or to unrelated protein molecules . Both MoAbs bind to intact T cells expressing the V beta domain (human V beta 8 and mouse V beta 11) from which selection peptides were derived, and costimulate a V beta specific in vitro T cell proliferative response induced by the staphylcoccal enterotoxin E (SEE) superantigen.

Biotechnol Appl Biochem, 1997 Jun, 25 ( Pt 3), 207 - 15
Use of pEX and pGEX bacterial heterologous protein expression systems for recombinant oncoprotein production and antisera generation; Pompeia C et al.; In order to study the role played by known and novel genes in growth control and neoplasia, we here compare the pEX and pGEX bacterial expression systems for recombinant oncoprotein production and for generation of specific antisera . The results of five pEX (MS2-c-Fos, MS2-Fra-1, MS2-JunD, bgal-c-Jun and bgal-JunB) and two pGEX {glutathione S-transferase (GSH)-JE/MCP-1 and GST-JunD} fusion-protein productions are presented . Higher (15-43-fold) yields are obtained with the pEX system, but only the pGEX system allows separation of the protein of interest from the fusion moiety by digestion with specific proteases . The degree of fusion-protein purification, as assessed by SDS/PAGE, is similar for both systems . Proteins produced by both systems were successfully used in the generation of specific antisera . The choice between the pEX and pGEX systems is dependent upon the specific recombinant protein produced.

Clin Infect Dis, 1997 Jun, 24(6), 1228 - 32
Broad-spectrum bacterial rDNA polymerase chain reaction assay for detecting amniotic fluid infection among women in premature labor; Hitti J et al.; We amplified bacterial 16S rRNA encoding DNA (rDNA) with the polymerase chain reaction (PCR) to detect amniotic fluid infection in 69 women in premature labor whose membranes were intact . Bacterial rDNA was detected by PCR in samples from 15 (94%) of 16 patients with positive amniotic fluid cultures . Bacteria were detected by PCR in samples from 5 (36%) of 14 patients with negative cultures and elevated interleukin (IL)-6 levels vs . 1 (3%) of 39 patients with negative cultures and IL-6 levels of < or = 2,000 pg/mL (P < .01) . The median amniotic fluid cytokine levels and the pregnancy outcomes were similar for patients with positive amniotic fluid cultures and those with negative cultures and positive rDNA PCR assays . The association between amniotic fluid infection and premature labor may be underestimated on the basis of amniotic fluid culture results . The broad-spectrum bacterial 16S rDNA PCR assay may prove useful for diagnosing amniotic fluid infection.

Genomics, 1997 Jun 1, 42(2), 217 - 26
Construction and characterization of a large-fragment chicken bacterial artificial chromosome library; Zimmer R et al.; A large-insert bacterial artificial chromosome (BAC) library has been constructed from male chicken genomic DNA using the new pBeloBAC11 vector . The library was prepared in two parts, such that two-thirds of the BAC library (2976 clones) had an average insert size of 490 kb (80 clones analyzed), after optimization of transformation and HMW DNA size-selection conditions . Fragments of increased average size were cloned by coupling a second size strategy using pulsed-field gel electrophoresis with optimized electroporation that favored transformation of Escherichia coli DH10B cells with very large plasmids . The initial one-third of this library (1440 clones) was constructed using the standard protocols and had an average insert size of 180 kb (40 clones analyzed) . The overall library consists, at present, of 4416 clones with a combined insert size average of 390 kb (ranging from 25 to 725 kb) . At least 95% of the BAC clones contain inserts . This is partially due to a second color selection performed with respect to white colonies, as well as to the optimized ligation conditions used . Based on the percentage of clones with inserts and the analysis of insert sizes, we estimate this library to represent a 0.8-fold coverage of the chicken genome . Southern blot analysis and fluorescence in situ hybridization were performed to confirm the identity of the BAC inserts with chicken genomic DNA . Analysis of large chicken BAC inserts showed that they were stably propagated for at least 120 cell generations . The results indicate that the BAC system is able to carry stably very large genomic fragments of chicken DNA, this system translating into a powerful tool for physical mapping and positional cloning of the chicken genome.

Proteins, 1997 Jun, 28(2), 217 - 26
Knowledge-based modeling of a bacterial dichloromethane dehalogenase; Marsh A et al.; A three-dimensional structural model of the dichloromethane dehalogenase (DCMD) from Methylophilus sp . DM11 is constructed based on sequence similarities to the glutathione S-transferases (GSTs) . To maximize sequence identity and minimize gaps in the alignment, a hybrid approach is used that takes advantage of the increased homology found between DM11 and domain I of the sheep blowfly theta class GST (residues 1-79) and domain II of the human alpha class GST (residues 81-222) . The resulting structure has C alpha root mean square deviations of 1.16 A in domain I and 1.83 A in domain II from the template GSTs, which compare well to those seen in other GST inter-class comparisons . The model is further applied to explore the structural basis for substrate binding and catalysis . A conserved network of hydrogen bonds is described that binds glutathione to the G site, placing the thiol group in a suitable location for nucleophilic attack of dichloromethane . A mechanism is proposed that involves activation through a hydrogen bond interaction between Ser12 and glutathione, similar to that found in the theta-GSTs . The model also demonstrates how aromatic residues in the hydrophobic site (H site) could play a role in promoting catalysis: His116 and Trp117 are ideally situated to accept a growing negative charge on a chlorine of dichloromethane, stabilizing displacement . This scheme is consistent with experimental results of single-point mutations and comparisons with other GST structures and mechanisms.

Hepatology, 1997 Jun, 25(6), 1334 - 7
Influence of malnutrition on the prevalence of bacterial translocation and spontaneous bacterial peritonitis in experimental cirrhosis in rats; Casafont F et al.; Bacterial translocation (BT) has been involved in the pathogenesis of spontaneous bacterial peritonitis (SBP) in experimental cirrhosis . Because malnutrition is a common feature in cirrhosis, the aim of this study was to evaluate the effect of nutrition on BT and SBP . We induced cirrhosis in 44 Sprague-Dawley rats by administration of oral CCl4, and, afterward, 26 animals were maintained with dietary restriction . Cultures of mesenteric lymph nodes (MLN), peripheral and portal blood, liver, and spleen were performed . SBP occurred in 48% of the rats with ascites, this being more frequent in the malnourished animals (80%) than in control rats (29%) . BT appeared in all the rats with SBP (100%) but only in 57% without it . In the malnourished animals, the BT rate was 95%, while it was 30% in the control group . These results suggest that malnutrition increases the BT rate and the risk of developing SBP in experimental cirrhosis, and that BT is frequent in cirrhosis and may play a role in the development of SBP.

Biomaterials, 1997 Jun, 18(12), 831 - 7
Physical property analysis and bacterial adhesion on a series of phosphonated polyurethanes; Baumgartner JN et al.; Glycerophosphorylcholine (GPC) was incorporated as the chain extender in a series of poly(tetramethylene oxide)-based polyurethane block copolymers . In order to determine the feasibility of use of these polyurethanes in biomedical devices, the effects of GPC incorporation on physical properties were studied . The effect of soft-segment molecular weight was also investigated . Biocompatibility of these materials was studied with regard to bacterial adhesion and protein deposition . Tensile testing showed that as GPC content increased, elongation at break decreased, while Young's modulus increased . Differential scanning calorimetry (DSC) results showed slightly decreased glass transition temperatures (Tgs) with increasing GPC content, indicating increased phase separation . Dynamic mechanical analysis (DMA) confirmed the decrease in Tg and the increase in rubbery plateau modulus with increasing GPC content . Water absorption was also increased with GPC content . Decreased bacterial adhesion was found on the GPC-containing materials compared to other functionalized polyurethanes . These experiments were carried out in a radial flow chamber utilizing automated video microscopy . Bacterial attachment was found to be lower on the GPC-containing polyurethanes both in the absence of and after pre-adsorption with plasma proteins.

Infect Control Hosp Epidemiol, 1997 Jun, 18(6), 426 - 39
How to select and interpret molecular strain typing methods for epidemiological studies of bacterial infections: a review for healthcare epidemiologists . Molecular Typing Working Group of the Society for Healthcare Epidemiology of America; Tenover FC et al.; Strain typing is an integral part of epidemiological investigations of nosocomial infections . Methods for distinguishing among bacterial strains have improved dramatically over the last 5 years, due mainly to the introduction of molecular technology . Although not all molecular techniques are equally effective for typing all organisms, pulsed-field gel electrophoresis is the technique currently favored for most nosocomial pathogens . Criteria to aid epidemiologists in interpreting results have been published . Nucleic acid amplification-based typing methods also are applicable to many organisms and can be completed within a single day, but interpretive criteria still are under debate . Strain typing cannot be used to replace a sound epidemiological investigation, but serves as a useful adjunct to such investigations.

J Cell Physiol, 1997 Jun, 171(3), 284 - 90
Bacterial lipopolysaccharide reduced intestinal barrier function and altered localization of 7H6 antigen in IEC-6 rat intestinal crypt cells; Kimura H et al.; The intestinal epithelial barrier restricts the passage of potentially toxic substances into the systemic circulation and is considered to be mostly mediated by tight junctions, though the mechanisms involved in the regulation of intestinal tight junctions are not yet fully understood . In the present study, we examined whether bacterial lipopolysaccharide (LPS) altered the barrier function of tight junction and localization of tight junctional proteins, ZO-1 and 7H6 antigen, in IEC-6 intestinal cells . Administration of LPS to the basolateral surface of IEC-6 cells disrupted the barrier function and caused the disappearance of 7H6 antigen from the cell border, whereas LPS administered to the apical surface altered neither the barrier function nor the localization of 7H6 antigen in IEC-6 cells . On the other hand, the localization of ZO-1 was not influenced by these treatments of LPS . These results suggest that the interaction of LPS with the basolateral surface of intestinal epithelial cells disrupts the barrier function and 7H6 antigen take part in the maintenance of the barrier function in IEC-6 cells.

Protein Expr Purif, 1997 Jun, 10(1), 115 - 22
Bacterial expression of human vitamin D-binding protein (Gc2) in functional form; Swamy N et al.; In this report, we report the first expression of human vitamin D-binding protein (hDBP), a serum protein with several functions and a multidomained structure, in Escherichia coli . The recombinant protein (reDBP) was expressed as a fusion partner of glutathione S-transferase in order to facilitate proper folding of the reDBP; E . coli-expressed DBP was found to be fully functional with respect to vitamin D sterol binding, interaction with actin, and cross-reactivity with anti-DBP antibody . Furthermore, both natural DBP and reDBP were affinity-labeled with 25-hydroxyvitamin D3-3-bromo{1-14C}acetate in a similar fashion . Availability of an expression system for hDBP in functional form provides opportunity to develop mutants and truncated DBPs to study multiple ligand-binding properties of this protein in relationship with its structure.

Gastroenterology, 1997 Jun, 112(6), 2056 - 64
Nitric oxide production by peritoneal macrophages of cirrhotic rats: a host response against bacterial peritonitis; Morales-Ruiz M et al.; BACKGROUND & AIMS: Patients and rats with cirrhosis and ascites are prone to develop peritonitis . The aim of this study was to assess whether peritoneal macrophages of cirrhotic rats without peritoneal infection produce nitric oxide and express inducible NO synthase (iNOS) . METHODS: NO2- accumulation produced by macrophages from control rats and cirrhotic rats with ascites was determined . iNOS messenger RNA and protein expression were analyzed by Northern and Western blot and immunocytochemical analysis . The in vivo effects of inhibiting iNOS were investigated by giving the specific iNOS inhibitor L-N-(1-iminoethyl)-lysine (L-NIL) or sterile saline to 9 and 7 cirrhotic rats with ascites, respectively . RESULTS: Cirrhotic macrophages produced NO2- that was around fourfold greater than that of control macrophages after 30 hours in culture . Northern and Western blot and immunocytochemical analysis showed the presence of iNOS messenger RNA and protein in macrophages of cirrhotic rats . Ascites cultures were positive in all rats administered L-NIL and negative in those administered saline . CONCLUSIONS: Macrophages of cirrhotic rats produce NO and express iNOS messenger RNA and protein, and these changes are not a consequence of overt bacterial infection . Because iNOS inhibition results in peritoneal infection, these results suggest that iNOS induction in macrophages of cirrhotic rats is a host defense response to prevent bacterial peritonitis.

Anal Biochem, 1997 Jun 1, 248(2), 265 - 8
Amplified enzyme-linked-immunofilter assays enable detection of 50-10(5) bacterial cells within 1 hour; Paffard SM et al.; Two enhanced enzyme-linked-immunofilter assay (ELIFA) methods for the rapid and quantitative detection of whole bacterial cells are described . In the first method, specific antibody bound to bacterial cells was amplified using a secondary antibody and detected by the conjugated enzyme activity (peroxidase) of a third antibody in a chemiluminescent assay . In the second method, a chromogenic substrate was used in conjunction with a biotinylated secondary antibody and avidin . Both assays were conducted within 55 min using a 96-well continuous flow immunofilter apparatus . The assay values were determined either as the reflectance of developed X-ray film placed over chemiluminescent membranes or of precipitated chromogen on the membrane surface . The biotin/avidin method enabled quantitative detection of approximately 60 to 10(5) cells . The detection limit (blank + 2 SD) of the chemiluminescent assay with a 30-s film exposure time was 50 cells . The ELIFA methods described represent a considerable advance in sensitivity over previous immunological methods of detecting whole bacterial cells and suggest that immunological methods may approach PCR in sensitivity.

Appl Environ Microbiol, 1997 Jun, 63(6), 2338 - 46
A new computational method for detection of chimeric 16S rRNA artifacts generated by PCR amplification from mixed bacterial populations; Komatsoulis GA et al.; A new computational method (chimeric alignment) has been developed to detect chimeric 16S rRNA artifacts generated during PCR amplification from mixed bacterial populations . In contrast to other nearest-neighbor methods (e.g., CHECK_CHIMERA) that define sequence similarity by k-tuple matching, the chimeric alignment method uses the score from dynamic programming alignments . Further, the chimeric alignments are displayed to the user to assist in sequence classification . The distribution of improvement scores for 500 authentic, nonchimeric sequences and 300 artificial chimeras (constructed from authentic sequences) was used to study the sensitivity and accuracy of both chimeric alignment and CHECK_CHIMERA . At a constant rate of authentic sequence misclassification (5%), chimeric alignment incorrectly classified 13% of the artificial chimeras versus 14% for CHECK_CHIMERA . Interestingly, only 1% of nonchimeras and 10% of chimeras were misclassified by both programs, suggesting that optimum performance is obtained by using the two methods to assign sequences to three classes: high-probability nonchimeras, high-probability chimeras, and sequences that need further study by other means . This study suggests that k-tuple-based matching methods are more sensitive than alignment-based methods when there is significant parental sequence similarity, while the opposite becomes true as the sequences become more distantly related . The software and a World Wide Web-based server are available at CHI.

Appl Environ Microbiol, 1997 Jun, 63(6), 2181 - 8
Bacterial population dynamics in a meromictic lake; Tuomi P et al.; Polyclonal antibodies against nine different bacteria isolated from Lake Saelenvannet in western Norway were produced, and the population dynamics of these strains in the lake were monitored through two spring seasons by immunofluorescence staining . The total counts of bacteria varied over time and space from 1.5 x 10(6) to 1.5 x 10(7) cells ml-1 . The counts of specific bacteria were in the range of 10(3) to 10(4) cells ml-1 or less; in sum, they generally made up less than 1% of the bacterial community . Some populations showed significant changes in abundance, with blooms lasting 1 to 3 weeks . The rate of change (increase and decrease) in abundance during blooms was estimated to be 0.2 to 0.6 day-1 . The average virus-to-bacteria ratio was 50, and there was a significant correlation between the abundances of virus and bacteria . Both protozoan grazing and lytic virus infection were assessed as possible mechanisms driving the variations in bacterial population density.

Infect Immun, 1997 Jun, 65(6), 2483 - 7
Modulation of neutrophil superoxide response and intracellular diacylglyceride levels by the bacterial pigment pyocyanin; Muller M et al.; Low concentrations of pyocyanin are reported to enhance superoxide production by human neutrophils exposed to various stimuli, yet the mechanism remains unknown . Using lucigenin-enhanced chemiluminescence, we examined the kinetics of the neutrophil superoxide response in the presence of pyocyanin . At all concentrations (12.5 to 200 microM), pyocyanin decreased the peak superoxide response while prolonging the duration of the response . The prolonged response may be associated with an observed increase in intracellular diacylglyceride levels due to pyocyanin exposure.

J Mol Evol, 1997 Jun, 44(6), 605 - 13
Nonplastid eukaryotic response regulators have a monophyletic origin and evolved from their bacterial precursors in parallel with their cognate sensor kinases; Pao GM et al.; We have analyzed all currently sequenced eukaryotic proteins containing either a kinase module or a receiver module, corresponding to those found in bacterial sensor kinases or response regulators, respectively, of the so-called two-component regulatory systems . We demonstrate that the eukaryotic receiver modules belong to a single subfamily of the bacterial receiver modules . Moreover, the cognate eukaryotic kinase modules exhibit a similar clustering pattern on the sensor kinase phylogenetic tree, suggesting that they evolved in parallel with the receiver modules from a common ancestral source that bore both modules . Multiple alignments of the sequences corresponding to these modules are presented and discussed, and eukaryotic-specific signature sequences are derived.

J Clin Invest, 1997 Jun 1, 99(11), 2616 - 24
Expression of bacterial superantigen genes in mice induces localized mononuclear cell inflammatory responses; Dow SW et al.; Bacterial superantigens are potent T cell activators, and superantigen proteins have been injected into mice and other animals to study T cell responses in vivo . When superantigen proteins are injected, however, the T cell stimulatory effects cannot be confined to specific tissues . Therefore, to target superantigen expression to specific tissues, we used gene transfer techniques to express bacterial superantigen genes in mammalian cells in vitro and in tissues in vivo . Murine, human, and canine cells transfected with superantigen genes in vitro all produced superantigen proteins both intracellularly and extracellularly, as assessed by bioassay, immunocytochemistry, and antigen ELISA . Superantigens produced by transfected eukaryotic cells retained their biologic specificity for T cell receptor binding . Intramuscular injection of superantigen plasmid DNA in vivo induced an intense intramuscular mononuclear cell infiltrate, an effect that could not be reproduced by intramuscular injection of superantigen protein . Intradermal and intravenous injection of superantigen DNA induced cutaneous and intrapulmonary mononuclear cell inflammatory responses, respectively . Thus, superantigen genes can be expressed by mammalian cells in vivo . Superantigen gene therapy represents a novel method of targeting localized T cell inflammatory reactions, with potential application to treatment of cancer and certain infectious diseases.

Transplantation, 1997 May 27, 63(10), 1411 - 5
Enhanced (cytomegalovirus) viral replication associated with septic bacterial complications in liver transplant recipients; Mutimer D et al.; BACKGROUND: Complications of the biliary anastomosis are the principal cause of clinically serious bacterial sepsis in liver transplant recipients . Reported series suggest an association of bacterial and fungal infection with cytomegalovirus (CMV) infection, although the mechanism of this association is unclear . METHODS: We examined the association of serious bacterial sepsis with CMV replication in a cohort of 106 consecutive liver transplant recipients . Sequentially collected buffy coats were examined with a polymerase chain reaction (PCR) assay that has been shown to have good predictive value for the development of CMV infection . For selected patients, CMV-specific IgM response and serum tumor necrosis factor-alpha (TNF-alpha) were also measured . RESULTS: Ten of 13 patients with serious bacterial sepsis developed buffy coat PCR positivity, compared with 26 of 93 patients without bacterial sepsis (chi-square, P<0.001) . Ten of 10 septic recipients with a seropositive liver donor developed PCR positivity . For 9 of 10 recipients, bacterial sepsis developed before PCR positivity . Bacterial sepsis was associated with high serum levels of TNF-alpha . Immune response to CMV (reflected by the appearance CMV-specific IgM) was apparently affected by bacterial sepsis, and IgM response was not observed for the three septic patients who died during the study period . CONCLUSIONS: We conclude that CMV replication is encouraged by serious bacterial sepsis . Replication may be promoted by high antecedent levels of TNF-alpha, and/or by poor immune response to CMV in the context of serious bacterial infection.

J Chromatogr B Biomed Sci Appl, 1997 May 23, 693(1), 79 - 91
Membrane adsorbers for selective removal of bacterial endotoxin; Petsch D et al.; Surface-modified flat-sheet microfiltration membranes were functionalised with poly-L-lysine, polymyxin B, poly(ethyleneimine), L-histidine, histamine, alpha-amylase and DEAE as well as deoxycholate . Their suitability to remove endotoxin from both buffers and protein solutions was examined using bovine serum albumin, murine IgG1 and lysozyme as model proteins . In protein-free solutions reduction from 6000 EU/ml to <0.1 EU/ml was achieved with all applied ligands; only alpha-amylase as well as L-histidine and histamine, when immobilized via the non-ionic spacer bisoxirane, exhibited low clearance factors at neutral pH . The adsorption of endotoxin is mainly ruled by electrostatic interaction forces . Thus in multi-component systems, such as endotoxin-contaminated protein solutions, competing interactions take place: acidic proteins compete with endotoxin for binding sites at the membrane adsorbers, basic proteins compete with the ligands for endotoxin and act as endotoxin carriers . With properly chosen conditions the membrane adsorbers presented here show exceptional effectiveness also in the presence of proteins . They are generally superior to functionalised Sepharose chromatographic sorbents and allow fast processing . They may contribute to reduce the risks in the application of parenterals and diagnostics.

J Biol Chem, 1997 May 23, 272(21), 13810 - 5
Uncoupling of ligand-binding affinity of the bacterial serine chemoreceptor from methylation- and temperature-modulated signaling states; Iwama T et al.; The Escherichia coli chemoreceptor Tsr mediates tactic responses to serine, repellents, and changes in temperature . We have previously shown that the serine-sensing ability of Tsr-T156C, which has a unique cysteine in place of threonine at residue 156, is specifically inactivated by thiol-modifying reagents and that L-serine protects the receptor from modification . In this study, we demonstrated the correlation between protective effects of various attractants and their potencies to elicit attractant responses . This indirect binding assay was used to monitor the affinity of the receptor for L-serine under various conditions . It has been demonstrated by in vitro assays that the ligand-binding affinities of Tsr and the related chemoreceptor Tar are unaffected by changes in the methylation state of the receptor . Using the serine protection assay, we re-examined this issue both in vitro and in vivo . The methylation levels of Tsr-T156C did not affect its ligand-binding affinity . We also showed both in vitro and in vivo that the ligand-binding affinity was unaffected by temperature . These results suggest that the structure of the periplasmic domain of the receptor is uncoupled from the signaling states of the cytoplasmic domain . This ligand-binding assay system should be applicable to other receptors.

Biochem Biophys Res Commun, 1997 May 19, 234(2), 506 - 10
A novel inhibitor of bacterial endotoxin derived from cinnamon bark; Azumi S et al.; A substance that inhibits the activity of bacterial endotoxin (LPS) was found in cinnamon bark . The inhibitor, extracted from dry cinnamon bark with 67% ethanol/water, was purified by using Limulus gelation activity as an indicator of endotoxin activity . The inhibitor suppressed the activity of the LPS when it was mixed with the inhibitor prior to the assay . The reduction of the LPS activity depended on the concentration of both the inhibitor and LPS when mixed, and also on the incubation time . The inhibitor suppressed the activity of all LPS and lipid A preparations tested regardless of the origin of the bacteria . The inhibitor alone did not affect the Limulus system . These results indicate that the inhibition was caused by direct interaction of the inhibitor with the LPS molecule . Furthermore the inhibitor abrogated the pyrogenicity of the LPS . Although it is uncertain whether the inhibitor actually plays a role in the defense mechanism in cinnamon bark, this is the first report that an inhibitor of bacterial endotoxin exists in a plant.

Presse Med, 1997 May 17, 26(16), 756 - 8
{Cerebrovascular complication in non-bacterial thrombotic endocarditis . Value of cardiac transesophageal ultrasonography}; Le Ber I et al.; BACKGROUND: Non-bacterial thrombotic endocarditis in patients with cancer can lead to ischemic stroke . Endocardial vegetations are usually small and may be missed at transthoracic echocardiography . CASE REPORT: Disseminated intravascular coagulation developed in a woman with ischemic stroke . Transthoracic echocardiography was normal . Four days later, transesophageal echocardiography revealed a large mitral vegetation suggesting non-bacterial thrombotic endocarditis . The diagnosis was confirmed at pathology which reported carcinoma of the colon . DISCUSSION: Transthoracic echocardiography is rarely contributed to the diagnosis of thrombotic endocarditis . In our patient transesophageal echocardiography grave the diagnosis before death instead of retrospectively at autopsy as usually occurs, demonstrating the value of transesophageal echocardiography for cancer patients who develop ischemic stroke.

Nucleic Acids Res, 1997 May 15, 25(10), 1950 - 6
Delivery of bacterial artificial chromosomes into mammalian cells with psoralen-inactivated adenovirus carrier; Baker A et al.; Molecular biology has many applications where the introduction of large (>100 kb) DNA molecules is required . The current methods of large DNA transfection are very inefficient . We reasoned that two limits to improving transfection methods with these large DNA molecules were the difficulty of preparing workable quantities of clean DNA and the lack of rapid assays to determine transfection success . We have used bacterial artificial chromosomes (BACs) based on the Escherichia coli F factor plasmid system, which are simple to manipulate and purify in microgram quantities . Because BAC plasmids are kept at one to two copies per cell, the problems of rearrangement observed with YACs are eliminated . We have generated two series of BAC vectors bearing marker genes for luciferase and green fluorescent protein (GFP) . Using these reagents, we have developed methods of delivering BACs of up to 170 kb into mammalian cells with transfection efficiency comparable to 5-10 kb DNA . Psoralen-inactivated adenovirus is used as the carrier, thus eliminating the problems associated with viral gene expression . The delivered DNA is linked to the carrier virus with a condensing polycation . Further improvements in gene delivery were obtained by replacing polylysine with low molecular weight polyethylenimine (PEI) as the DNA condensing agent.

Proc Natl Acad Sci U S A, 1997 May 13, 94(10), 5101 - 6
A mammalian mitochondrial drug receptor functions as a bacterial "oxygen" sensor; Yeliseev AA et al.; The rat mitochondrial outer membrane-localized benzodiazepine receptor (MBR) was expressed in wild-type and TspO- (tryptophan-rich sensory protein) strains of the facultative photoheterotroph, Rhodobacter sphaeroides 2.4.1, and was shown to retain its structure within the bacterial outer membrane as assayed by its binding properties with a variety of MBR ligands . Functionally, it was able to substitute for TspO by negatively regulating the expression of photosynthesis genes in response to oxygen . This effect was reversed pharmacologically with the MBR ligand PK11195 . These results suggest a close evolutionary and functional relationship between the bacterial TspO and the MBR . This relationship provides further support for the origin of the mammalian mitochondrion from a "photosynthetic" precursor . Finally, these findings provide novel insights into the physiological role that has been obscure for the MBR in situ.

J Biol Chem, 1997 May 2, 272(18), 11850 - 5
Uncoupled phosphorylation and activation in bacterial chemotaxis . The 2.3 A structure of an aspartate to lysine mutant at position 13 of CheY; Jiang M et al.; An aspartate to lysine mutation at position 13 of the chemotaxis regulatory protein CheY causes a constitutive tumbly phenotype when expressed at high copy number in vivo even though the mutant protein is not phosphorylatable . These properties suggest that the D13K mutant adopts the active, signaling conformation of CheY independent of phosphorylation, so knowledge of its structure could explain the activation mechanism of CheY . The x-ray crystallographic structure of the CheY D13K mutant has been solved and refined at 2.3 A resolution to an R-factor of 14.3% . The mutant molecule shows no significant differences in backbone conformation when compared with the wild-type, Mg2+-free structure, but there are localized changes within the active site . The side chain of lysine 13 blocks access to the active site, whereas its epsilon-amino group has no bonding interactions with other groups in the region . Also in the active site, the bond between lysine 109 and aspartate 57 is weakened, and the solvent structure is perturbed . Although the D13K mutant has the inactive conformation in the crystalline form, rearrangements in the active site appear to weaken the overall structure of that region, potentially creating a metastable state of the molecule . If a conformational change is required for signaling by CheY D13K, then it most likely proceeds dynamically, in solution.

Radiat Med, 1997 May-Jun, 15(3), 185 - 7
Spontaneous bacterial peritonitis in cirrhosis: enhancement of ascites on delayed MR imaging; Kanematsu M et al.; Delayed contrast enhancement of ascites in MR imaging performed in a 61-year-old cirrhotic patient who developed spontaneous bacterial peritonitis is discussed . Delayed T1-weighted spin-echo MR images after the IV injection of gadolinium-diethylenetriamine penta-acetic acid (Gd-DTPA) showed remarkable enhancement of ascites . The ascites showed marked elevation in total protein value and neutrophil count, establishing a diagnosis of spontaneous bacterial peritonitis . This case suggests the potency of delayed-enhancement MR imaging for the prediction of spontaneous bacterial peritonitis in cirrhotic patients.

Radiats Biol Radioecol, 1997 May-Jun, 37(3), 291 - 6
{The combined action of ionizing radiation and sodium nitrate on bacterial cells}; Dergacheva IP et al.; The survival of bacterial cells Escherichia coli exposed to sodium nitrate (1-5 M) simultaneously with 60Co gamma rays was shown to be smaller than that expected for independent addition of the effects induced by each of agents applied separately . The synergistic effect was quantitatively estimated by the factor k, which is the ratio of the isoeffective doses on the calculated additive survival curve and the experimental one . The dependencies of k on the exposition of combined action of gamma rays and different NaNO3 solutions (1, 3 and 5 M) are presented . It was demonstrated that the synergistic ratio k was increased with exposure duration increasing . It is suggested that in this case the synergistic effect may be related with the formation of some additional lethal damage due to NaNO3 radiochemical transformation products.

Kaohsiung J Med Sci, 1997 May, 13(5), 328 - 31
Bacterial meningitis and lumbar epidural hematoma due to lumbar acupunctures: a case report; Chen CY et al.; A 48-year-old female expressed signs of meningeal irritation after having received several lumbar acupunctures within one week for back pain . Bacterial meningitis was diagnosed from cerebrospinal fluid examinations . Magnetic resonance image (MRI) of spine at admission demonstrated a fusiform lesion with characters of subacute hematoma in the epidural space of the first and second lumbar level . She received antibiotics treatment only and recovered from her central nervous system infection completely . The epidural lesion disappeared spontaneously in the MRI follow up three weeks later . We report the diagnosis and follow-up of epidural hematoma of the lumbar spine by MRI which aided the medical physician to treat meningitis attentively.

Can J Gastroenterol, 1997 May-Jun, 11(4), 361 - 6
Bacterial glycosulphatases and sulphomucin degradation; Robertson AM et al.; The presence of a high bacterial population in a region of the gastrointestinal tract is usually associated with the secretion of sulphomucins into the mucus gel covering that region . The term 'sulphomucin' is a histochemical description of the staining properties of mucin . At present this term can only be qualitatively related to the percentage of sulphate in the mucin molecule, which makes the term difficult to use in a biochemical and functional sense . Sulphomucins are thought to carry out the normal functions attributed to mucins; in addition, heavy sulphation rate-limits the degradation of mucins by bacterial mucin-degrading glycosidases . A number of mucin-specific glycosulphatases have been reported in bacteria, although only two such enzymes have been purified . These enzymes remove part of the sulphate content from sulphomucins and make them more susceptible to further enzymic degradation . The variety of chain locations and sugar attachment sites of sulphate esters on the mucin oligosaccharides, taken together with the data on the enzymes, suggest there will be a spectrum of bacterial glycosulphatases, with different properties, cellular locations and substrate specificities . Bacterial glycosulphatases have the potential to modify sulphated glycoconjugates at mucosal surfaces and should prove useful as biochemical tools for the study of sulphated glycoconjugates.

Protein Eng, 1997 May, 10(5), 497 - 500
Identification of membrane spanning beta strands in bacterial porins; Gromiha MM et al.; The membrane assembly of outer membrane proteins is more complex than that of transmembrane helical proteins owing to the intervention of many charged and polar residues in the membrane . Accordingly, the predictive accuracy of transmembrane beta strands is considerably lower than that of transmembrane alpha helices . In this paper we develop a set of conformational parameters for membrane spanning beta strands . We formulate an algorithm to predict the transmembrane beta strands in the family of bacterial porins based on the conformational parameters and surrounding hydrophobicities of amino acid residues . A Fortran program has been developed which takes the amino acid sequence as the input file and gives the predicted transmembrane beta strand as output . The present method predicts at an accuracy level of 82% for all the bacterial porins considered.

J Photochem Photobiol B, 1997 May, 39(1), 63 - 72
Photosensitizing activity of the anti-bacterial drugs sulfamethoxazole and trimethoprim; Zhou W et al.; The photochemical reactions in vitro of sulfamethoxazole alone and in combination with trimethoprim were studied to obtain information on the photosensitization mechanism . Sulfamethoxazole in aqueous solution, on exposure to UVB radiation, generates free radicals and singlet oxygen, with the neutral molecule being at least twice as active as the sulfamethoxazole anion . Photoexcited sulfamethoxazole can participate in electron transfer to cytochrome-c and nitro blue tetrazolium, and sensitizes the peroxidation of linoleic acid and the hemolysis of human erythrocytes, predominantly by a free radical mechanism . Trimethoprim is relatively inactive in the same photochemical systems.

Acta Otolaryngol, 1997 May, 117(3), 329 - 36
Possible involvement of nitric oxide in the sensorineural hearing loss of bacterial meningitis; Amaee FR et al.; Microperfusion of scala tympani with the NO donors, sodium nitroprusside (SNP) and S-nitroso-N-acetylpenicillamine (SNAP), produced marked depression of the compound action potential (CAP) and cochlear microphonic (CM) together with severe and widespread morphological damage to hair cells and supporting cells in the organ of Corti . In addition, direct perfusion of N-methyl-D-aspartate (NMDA) into scala tympani, which probably induces excess stimulation of NMDA receptors within the cochlea and which is known to lead to the release of NO, was found to elicit similar electrophysiological and structural lesions in the cochlea . Pre-perfusion of scala tympani with L-methyl arginine (L-MA), which inhibits the release of NO, or superoxide dismutase (SOD), an O2-scavenger, conferred marked protection upon the cochlea from the lesions caused by NO donors . These observations indicate that enhanced NO production is likely to be an important factor responsible for pathological insult of the cochlea . The possibility is discussed that this factor is involved in the chain of events leading to hearing loss caused by bacterial meningitis . Such hearing loss is a major sequela of bacterial meningitis in children.

Jpn Circ J, 1997 May, 61(5), 450 - 4
Arthritis and meningitis--the first manifestations of bacterial endocarditis in 2 patients; Suzuki J et al.; We have encountered 2 patients in whom the first manifestations of bacterial endocarditis were arthritis (in 1 case septic arthritis and in the other nonseptic arthritis) and bacterial meningitis . These presentations were followed by acute heart failure due to aortic valve destruction, although the patients showed no significant cardiovascular manifestations on admission . Aortic valve replacement was performed in each case and the patients' postoperative course was comfortable . We would like to emphasize the following points . (1) Arthritis and meningitis are uncommon in patients with bacterial endocarditis . However, it is necessary to consider the possibility of bacterial endocarditis when these clinical manifestations present together . Such a combination can cause rapid valve destruction . When more than 2 rare complications of bacterial endocarditis coexist, surgery should be considered as soon as the definite diagnosis of bacterial endocarditis is established, even if congestive heart failure has not yet developed . (2) Arthritis associated with bacterial endocarditis might be truly septic rather than mediated by circulating immune complexes as is commonly believed.

Eur J Clin Invest, 1997 May, 27(5), 409 - 16
Small bowel bacterial overgrowth in patients after total gastrectomy; Bragelmann R et al.; The aim of this study was to elucidate the consequences of small bowel bacterial overgrowth (SBBO) after total gastrectomy . A total of 127 patients, evaluated for SBBO with a radiographically controlled H2-breath test (subgroup I, without SBBO, n = 80; subgroup II, with SBBO, n = 47) after potentially curative total gastrectomy for gastric malignancy, were uniformly evaluated . Mean time since operation was significantly shorter in subgroup II than in subgroup I {370 days, confidence interval (CI) 96-645 days, vs . 687 days, CI 397-976 days; P < 0.01} . Controlling for this difference, there were no other significant differences in symptoms and signs between the subgroups except for the medico-social functioning measured with the Edinburgh Rehabilitation Status Scale (ERSS) . The mean ERSS showed significantly better medicosocial functioning in subgroup I than in subgroup II {3.7 (CI 2.2-5.2) vs . 5.1 (CI 3.0-7.0); P < 0.05} . After total gastrectomy, patients without SBBO did not differ significantly from patients with SBBO in most parameters . Medicosocial functioning was significantly poorer in the latter.

Respir Med, 1997 May, 91(5), 317 - 21
Interleukin-8 and leukotriene B4 in bronchoalveolar lavage fluid from HIV-infected patients with bacterial pneumonia; Krarup E et al.; Human immunodeficiency virus (HIV)-infected patients are at increased risk of contracting bacterial infections, mainly pneumonia . Despite this, little is known about immunopathogenic mechanisms in HIV-related bacterial pneumonia . This paper investigates the presence of the neutrophil chemotactic mediators, interleukin-8 (IL_8) and leukotriene B4 (LTB4), in bronchoalveolar lavage (BAL) fluid from 27 HIV-infected patients with bacterial pneumonia . Significantly elevated levels of IL-8 were found in BAL fluid of patients with bacterial pneumonia {529 pg ml-1 (296-1161 pg ml-1)} compared to matched patients with Pneumocystis carinii pneumonia (PCP) {59 pg ml-1 (42-254 pg ml-1)} and healthy controls {58 pg ml-1 (37-82 pg ml-1)} . Levels of LTB4 were not elevated during bacterial pneumonia when compared to PCP patients and healthy controls . Furthermore, a positive correlation was found between IL-8 levels in BAL fluid and relative BAL neutrophilia (r = 0.60, P = 0.001) in bacterial pneumonia . In conclusion, elevated IL-8 levels in BAL fluid were found in patients suffering from bacterial pneumonia, which may account for the influx of neutrophils to the lung, whereas LTB4 appears not to be an important chemotactic factor in this setting.

Biochem J, 1997 May 1, 323 ( Pt 3), 603 - 9
Modified proenzymes as artificial substrates for proteolytic enzymes: colorimetric assay of bacterial collagenase and matrix metalloproteinase activity using modified pro-urokinase; Verheijen JH et al.; We describe a new principle for assessment of the activity of proteolytic enzymes of all classes and show the application of this principle for the quantitative assay of bacterial collagenase and human matrix metalloproteinases (MMPs) . Central to this new principle is the presence of a proenzyme that can be activated into an active enzyme by a single proteolytic event . The regular activation sequence in the proenzyme is replaced using protein engineering by an artificial sequence recognized by the proteinase to be determined . The latter can act as an activator for the newly engineered proenzyme . In the present paper a simple colorimetric assay for the determination for MMPs is described based on this principle . With the aid of protein engineering, a modified pro-urokinase has been prepared in which the activation sequence normally recognized by plasmin (Pro-Arg-Phe-Lys upward arrowIle-Ile-Gly-Gly) has been replaced by a sequence expected to be recognized and hydrolysed by many MMPs (Arg-Pro-Leu-Gly upward arrowIle-Ile-Gly-Gly) . The active urokinase resulting from activation of the modified pro-urokinase by a MMP could be measured either directly, using a specific chromogenic peptide substrate for urokinase, or indirectly via urokinase-catalysed plasminogen activation . The response of the assay to equal molar quantities of active MMPs decreases in the order MMP-2>MMP-9>MMP-1>MMP-3>MMP-7 . The detection limit for MMP-9 was below 15 pM, corresponding to 3 . 75x10(-15) mol per assay . Using the assay, increased MMP activity was detected in synovial tissue extracts from rheumatoid arthritis patients compared with those from osteoarthritis patients, and in stomach tumour extracts as compared with normal stomach tissue extracts.

Toxicol Appl Pharmacol, 1997 May, 144(1), 77 - 87
Bacterial endotoxin enhances the hepatotoxicity of allyl alcohol; Sneed RA et al.; Lipopolysaccharide (LPS), or bacterial endotoxin, causes liver damage at relatively large doses in rats . Smaller doses, however, may influence the response to other hepatotoxicants . The purpose these studies was to examine the effect of exposure to relatively all doses of LPS on the hepatotoxic response to allyl alcohol, which causes periportal necrosis in laboratory rodents through an known mechanism . Rats were pretreated with LPS (100 micrograms/kg) 2 hr before treatment with a minimally toxic dose of allyl alcohol mg/kg), and liver toxicity was assessed 18 hr later from activity of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in plasma and from histologic changes in liver sections . Plasma ALT and AST activities were not elevated significantly in rats treated with vehicle, LPS, or allyl alcohol alone, but pronounced increases were observed in rats treated with LPS and allyl alcohol . Significant liver injury occurred as early as 2 hr after allyl alcohol treatment in LPS-pretreated rats and peaked at 6 hr . LPS treatment did not affect the activity of alcohol dehydrogenase and did not affect the rate of production of NADH in isolated livers perfused with allyl alcohol; thus, LPS does not appear to increase the metabolic bioactivation of allyl alcohol into acrolein . On the other hand, pretreatment with 4-methylpyrazole, an inhibitor of alcohol dehydrogenase, abolished the hepatotoxicity of allyl alcohol in LPS-treated rats, indicating that production of acrolein was needed for LPS enhancement of the toxicity of allyl alcohol . Pretreatment of rats with gadolinium chloride (10 mg/kg), a known inactivator of Kupffer cell phagocytic function, decreased LPS augmentation of the response to allyl alcohol . These data indicate that LPS markedly enhances the hepatotoxic response to allyl alcohol . Furthermore, the results suggest that the LPS-induced enhancement of allyl alcohol hepatotoxicity occurs through a Kupffer cell-dependent mechanism.

Acta Cytol, 1997 May-Jun, 41(3), 755 - 8
Value of Gram's stain of cell block material from peritoneal fluid in bacterial peritonitis; Renshaw AA et al.; OBJECTIVE: To determine the value of Gram's stain of cell blocks of peritoneal fluid for the diagnosis of bacterial peritonitis . STUDY DESIGN: The results of Gram's stain of 12 cases of culture-positive, frank bacterial peritonitis (FBP) and 11 cases of culture-positive spontaneous bacterial peritonitis (SBP) were compared with 6 cases of culture-negative frank sterile peritonitis and 21 cases of culture-negative spontaneous sterile peritonitis . RESULTS: For both FBP and SBP, Gram's stain had low sensitivity (8% and 9%) . Overall, the positive predictive value of Gram's stain for peritonitis was 33% . Hematoxylin-eosin (HE) was just as sensitive but had a positive predictive value of 100% . CONCLUSION: In cell block material of peritoneal fluid, Gram's stain is of little value except to further characterize organisms seen on HE.

Plant Cell, 1997 May, 9(5), 717 - 30
ALBINO3, an Arabidopsis nuclear gene essential for chloroplast differentiation, encodes a chloroplast protein that shows homology to proteins present in bacterial membranes and yeast mitochondria; Sundberg E et al.; The albino3 (alb3) mutant of Arabidopsis forms white or light yellow cotyledons and leaves and when germinated on soil does not survive beyond the seedling stage . The chloroplasts of the mutant are abnormal, as determined by electron microscopy, and contain reduced levels of chlorophyll . However, the chloroplasts of alb3 mutants are sufficiently differentiated to enable the expression of two nuclear genes whose transcription requires the presence of chloroplasts . The ALB3 gene was isolated by transposon tagging with the Activator/Dissociation transposable element system . ALB3 is a novel plant gene whose product shows homology to a bacterial membrane protein previously identified in five bacterial species and to a yeast protein, OXA1, and its human homolog . OXA1 is required in the mitochondria for proper assembly of the cytochrome oxidase complex . ALB3 does not have a function identical to OXA1 because mitochondrial cytochrome oxidase activity is not affected in the mutant, and immunogold labeling as well as chloroplast import experiments performed in vitro demonstrated that the ALB3 protein is present in chloroplast membranes . ALB3 might have a function related to that of OXA1 and be involved in the assembly of a chloroplast enzyme complex.

Gastrointest Endosc, 1997 May, 45(5), 400 - 5
Biliary manometry, bacterial characteristics, bile composition, and histologic changes fifteen to seventeen years after endoscopic sphincterotomy; Bergman JJ et al.; AIM: To evaluate the function of the biliary sphincter 15 to 17 years after endoscopic sphincterotomy and to investigate if loss of sphincter function is associated with bacterial colonization, changes in bile composition, or inflammation of the biliary system . METHODS: Eight patients who had undergone endoscopic sphincterotomy for bile duct stones 15 to 17 years previously underwent ERCP with biliary manometry, bile sampling, and biopsy . Manometry was performed using a perfused triple-lumen manometry catheter and a station pull-through technique . Bile samples were cultured and analyzed for biliary lipids, bile salts, bacterial beta-glucuronidase, and phospholipase A2 . Biopsy specimens were taken from the proximal common heptic duct for histologic examination . RESULTS: Manometry demonstrated absent basal sphincter pressure and no choledochoduodenal pressure gradient in all patients . Phasic contractions were observed in two patients . Cholangiography showed stones in one patient . Positive cultures were obtained in three patients, including the patient with stones . All bile samples showed a high content of biliary lipids and cholesterol . Some samples contained considerable amounts of hydrophobic bile salts . Five samples contained very high levels of phospholipase A2 activity . Significant bacterial beta-glucuronidase activity was found in one patient, the patient with stones . Biopsy specimens of the proximal common hepatic duct in three patients showed chronic inflammation with fibrosis and reactive epithelial changes . CONCLUSIONS: After endoscopic sphincterotomy for bile duct stones, the function of the biliary sphincter is permanently lost . This is associated with bacterial colonization, presence of cytotoxic components in the bile, and chronic inflammation of the biliary system.

J Am Dent Assoc, 1997 May, 128(5), 617 - 23
A chemical treatment regimen to reduce bacterial contamination in dental waterlines; Eleazer PD et al.; This article describes a pilot study in which the authors used aerobic bacterial cultures to compare the effects of 1:10 mouthwash, 1:20 mouthwash and 2 percent ethanol in reservoir systems with seven conventional water systems . The long-term, low-concentration antiseptic reduced bacteria to within acceptable limits.

RNA, 1997 May, 3(5), 464 - 75
The path of mRNA through the bacterial ribosome: a site-directed crosslinking study using new photoreactive derivatives of guanosine and uridine; Sergiev PV et al.; Two new photoreactive nucleotide derivatives have been applied in site-directed crosslinking studies with mRNA analogues . 6-Thioguanosine triphosphate or 5-methyleneaminouridine triphosphate was incorporated into mRNA analogues by T7 transcription; after transcription, the 5-methyleneaminouridine residues were converted to a diazirine derivative . mRNA analogues carrying either 6-thioguanosine or the diazirine derivative were bound to Escherichia coli ribosomes in the presence of tRNA(f)(Met), and photo-crosslinking was induced by irradiation at 350 nm . With 6-thioguanosine, specific crosslinks were observed from downstream positions +8 or +9 of the mRNA to nt 1196 in helix 34 of the 16S rRNA, and from position +12 to nt 530 in helix 18 . With the diazirine derivative, a crosslink from position +2 (within the AUG codon) to nt 926 in helix 28 was found . Taken together with previous data obtained from downstream sites in mRNA analogues carrying 4-thiouridine residues, specific crosslinks have now been identified from downstream mRNA positions +2, +4, +6, +7, +8, +9, +11, and +12 . The data confirm that the three 16S rRNA regions involved-helices 18, 28, and 34-are in the direct neighborhood of the decoding area of the 30S subunit.

Genetics, 1997 May, 146(1), 27 - 38
The evolution of bacterial transformation: sex with poor relations; Redfield RJ et al.; Bacteria are the only organisms known to actively take up DNA and recombine it into their genomes . While such natural transformation systems may provide many of the same benefits that sexual reproduction provides eukaryotes, there are important differences that critically alter the consequences, especially when recombination's main benefit is reducing the mutation load . Here, analytical and numerical methods are used to study the selection of transformation genes in populations undergoing deleterious mutation . Selection for transformability depends on the shape of the fitness function against mutation . If the fitness function is linear, then transformation would be selectively neutral were it not for the possibility that transforming cells may take up DNA that converts them into nontransformable cells . If the selection includes strong positive (synergistic) epistasis, then transformation can be advantageous in spite of this risk . The effect of low quality DNA (from selectively killed cells) on selection is then studied analytically and found to impose an additional cost . The limited data available for real bacterial populations suggest that the conditions necessary for the evolution of transformation are unlikely to be met, and thus that DNA uptake may have some function other than recombination of deleterious mutations.

Pediatr Res, 1997 May, 41(5), 647 - 50
Expression of MxA protein in blood lymphocytes discriminates between viral and bacterial infections in febrile children; Halminen M et al.; Interferons (IFNs), which are induced by viruses, form an essential part of host's defense systems against viral infections . The antiviral actions of IFNs are mediated by several IFN-inducible gene products, one of which is Mx protein . To evaluate whether MxA protein expression in lymphocytes could function as an indicator of endogenous IFN production in children with acute febrile illness, we analyzed MxA protein levels in peripheral blood lymphocytes by flow cytometry in the acute phase of the disease . Children with a laboratory-confirmed viral infection {respiratory syncytial virus (RSV) in 21, adenovirus in 10, rotavirus in 5, and influenza, herpes simplex, or EBV in 7 other cases} had significantly higher (p < 0.002) MxA protein levels (median fluorescences in different virus groups ranged from 707 to 765) compared with children with a bacterial infection (n = 12, median fluorescence 548) . To characterize further MxA protein expression during infections, cells from 41 patients were stimulated in vitro with exogenous IFN-alpha, and the level of MxA protein expression was determined . The rise in MxA staining levels was significantly higher in the group with bacterial infections compared with those with viral infection (p < 0.005), further indicating that the MxA protein levels were already elevated in vivo in patients with viral infections . This study suggests that elevated MxA protein expression levels can be used in the differential diagnosis of bacterial versus viral disease in febrile children.

J Immunol, 1997 May 1, 158(9), 4500 - 6
Molecular properties of anti-DNA induced in preautoimmune NZB/W mice by immunization with bacterial DNA; Wloch MK et al.; To elucidate the mechanism of Ag drive in the anti-DNA response, the Ab response to bacterial DNA has been analyzed in normal and autoimmune mice . Preautoimmune NZB/W mice immunized with Escherichia coli dsDNA produce Abs that resemble spontaneous autoantibodies and bind mammalian dsDNA . In contrast, normal mice, when immunized similarly, produce Abs that bind only bacterial dsDNA . To characterize further the responsiveness of NZB/W mice to bacterial DNA, we determined the molecular properties of mAbs from preautoimmune NZB/W mice immunized with E . coli DNA . Of nine Abs studied, all were IgM and all bound mammalian ssDNA, while four had appreciable reactivity with mammalian dsDNA . The induced anti-dsDNA resembled spontaneous anti-DNA from autoimmune mice in V gene utilization and V(H) CDR3 arginine content . These Abs lacked evidence of somatic mutation, however, indicating that affinity maturation via somatic mutation is not essential for dsDNA reactivity . The findings suggest that preautoimmune NZB/W mice have immunoregulatory defects that allow activation of mammalian dsDNA reactive B cells by bacterial DNA.

Aten Primaria, 1997 Apr 30, 19(7), 357 - 60
{A comparison of 2 clinical laboratory methods in the diagnosis of bacterial vaginosis}; Gonzalez-Pedraza-Aviles A et al.; OBJECTIVE: To determine the sensitivity, the specificity, and positive and negative predictive values of two laboratory methods used to diagnose bacterial vaginosis; Gram stain and the Gardnerella vaginalis culture, in comparison with the clinical sings of vaginal discharge; homogeneous secretion, pH > 4.7, positive amine test and the presence of clue cells . DESIGN: A prospective, comparative and crossover type . SETTING: This study was carried out in the Health Center "Dr . Jose Castro Villagrana" SSA, situated in Tlalpan, Mexico City . From January, 1992 to July, 1996 . PARTICIPANTS: 3,142 women, from 16 to 55 years old with cervicovaginitis diagnosis, without previous treatment and sexual active life history . RESULTS: By means of clinical criterion (33.1%), it was diagnosed 1,041 women with bacterial vaginosis . Statistical differences were not found between the culture and Gram stain in the presence or no-presence of bacterial vaginosis diagnosed by clinical criterion (p = 0.33) The clue cells were the best predictor of bacterial vaginosis . CONCLUSIONS: The differences between both methods analysed were minimal and they didn't have statistical value so that, it is proposed the Gram stain as diagnostic method of bacterial vaginosis based on factors like speed, reproductiveness and low cost.

Mol Gen Genet, 1997 Apr 28, 254(4), 400 - 6
Genetic evidence of a coupling role for the TraG protein family in bacterial conjugation; Cabezon E et al.; The ability of conjugative plasmids from six different incompatibility groups to mobilize a set of mobilizable plasmids was examined . The mobilization frequencies of plasmids RSF1010, ColE1, ColE3, and CloDF13 varied over seven orders of magnitude, depending on the helper conjugative plasmid used . Mobilization of CloDF13 was unique in that it did not require TrwB, TraG or TraD (all members of the TraG family) for mobilization by R388, RP4 or F, respectively . CloDF13 itself codes for an essential mobilization protein (MobB) which is also a TraG homolog, only requiring a source of the genes for pilus formation . Besides, CloDF13 was mobilized efficiently by all conjugative plasmids, suggesting that TraG homologs are the primary determinants of the mobilization efficiency of a plasmid, interacting differentially with the various relaxosomes . Previous results indicated that TraG and TrwB were interchangeable for mobilization of RSF1010 and ColE1 by PILw (the pilus system of IncW plasmids) but TraG could not complement conjugation of trwB mutants, suggesting that additional interactions were taking place between TrwB and oriT(R388) that were not essential for mobilization . To further test this hypothesis, we analyzed the mobilization frequencies of ColE1 and RSF1010 by the P, W, and F pili in the presence of alternative TraG homologs . The results obtained indicated that the frequency of mobilization was determined both by the particular TraG-like protein used and by the pilus system . Thus, TraG-like proteins are not generally interchangeable for mobilization . Therefore we suggest that the factors that determine the frequencies of transfer of different MOB regions are the differential interactions of TrwB with pilus and relaxosome.

Biochem Biophys Res Commun, 1997 Apr 28, 233(3), 848 - 52
Bacterial scavengase p20 is structurally and functionally related to peroxiredoxins; Zhou Y et al.; Scavengase p20 was recently identified as a novel family of bacterial antioxidant enzymes possessing thioredoxin-linked thiol peroxidase activity . In this study, the Escherichia coli gene coding for scavengase p20 was isolated from three different strains and the nucleotide sequence was determined . Multiple alignment of amino acid sequence revealed that a previously unidentified Cys-61 is most conserved among all bacterial p20 scavengases and corresponds to the active site in the well-characterized peroxiredoxins . Phylogenetic analysis further supported that scavengase p20 is a novel subfamily of peroxiredoxins . Site-directed mutagenesis studies demonstrated that Cys-61 is indispensable for the antioxidant activities of scavengase p20 . Taken together, our findings strongly suggest that the p20 scavengases are structurally and functionally related to peroxiredoxins.

Gene, 1997 Apr 21, 189(2), 159 - 62
A bacterial cloning vector using a mutated Aequorea green fluorescent protein as an indicator; Inouye S et al.; The bacterial cloning vector, pGreenscript A, derived from the mutated Aequorea green fluorescent protein (GFP-S65A) gene, when expressed in E . coli produced colonies that showed yellow color under daylight and strong green fluorescence under long-wave ultraviolet light . The vector was used to select for inserted foreign genes based on the loss of the yellow color/green fluorescence of E . coli cells caused by the insertional inactivation of GFP production.

Neurosci Lett, 1997 Apr 18, 226(1), 17 - 20
Histamine (H1) receptor antagonist inhibits leukocyte rolling in pial vessels in the early phase of bacterial meningitis in rats; Weber JR et al.; The present study tested the hypothesis whether a histamine dependent pathway is involved in leukocyte-endothel interaction in the early phase of bacterial meningitis . Using confocal laser scanning microscopy we investigated leukocyte rolling in brain venules in vivo during 4 h in experimental pneumococcal meningitis in the rat . Leukocyte rolling, but not firm adhesion induced by intracisternally (i.c.) injected pneumococcal cell wall components, was temporarily inhibited (2 h, 5.6 +/- 1.9 vs . 2.3 +/- 0.9; 3 h, 7.4 +/- 2.7 vs . 3.1 +/- 1.3/100 microm/min) by diphenhydramine, a histamine H1 receptor antagonist . Histamine, possibly released by activated mast cells, is known to initiate P-selectin upregulation and subsequent leukocyte rolling . This data suggest that histamine is a mediator of leukocyte rolling in the early phase of bacterial meningitis.

J Immunol, 1997 Apr 15, 158(8), 3626 - 34
CD4+ T cell down-regulation in human intestinal mucosa: evidence for intestinal tolerance to luminal bacterial antigens; Khoo UY et al.; T cells from the intestinal mucosal proliferate poorly in vitro, and the contribution of Ag-specific recognition to this hyporesponsiveness is unclear, since the Ag repertoire of intestinal mucosal T cells is unknown . In this study, T cell proliferation in response to Ag-prepulsed autologous peripheral blood-derived APC was examined . Whereas T cells from peripheral blood proliferated to inner membrane and cytoplasmic Escherichia coli proteins, T cells from intestinal mucosa responded only to purified component Ags of these proteins and not to their combination . This suggests that the lack of proliferation in response to these Ags presented as a mixture is not due to the absence of E . coli-specific T cells in the mucosa, but, rather, to down-regulation after T cell recognition . Down-regulation was assayed by measuring the inhibition of autologous peripheral blood T cell proliferation in response to Ag-prepulsed APC . Coculture with leukocytes from intestinal mucosa and not from mesenteric lymph nodes, inhibited autologous peripheral blood T cell proliferation in response to E . coli proteins, but not to tetanus toxoid, PHA, or IL-2 . Inhibition was independent of cell contact, provided APC were available to the mucosal cell population, and was reversible by neutralization of IL-10 or TGF-beta with mAb or depletion of mucosal CD4+ T cells . Taken together, the data suggest that mucosal T cell unresponsiveness to luminal Ags is mediated by production of inhibitory cytokines after specific Ag recognition by CD4+ T cells.

J Biol Chem, 1997 Apr 11, 272(15), 9690 - 6
GTP cyclohydrolase I feedback regulatory protein is a pentamer of identical subunits . Purification, cDNA cloning, and bacterial expression; Yoneyama T et al.; GTP cyclohydrolase I feedback regulatory protein (GFRP) mediates feedback inhibition of GTP cyclohydrolase I activity by tetrahydrobiopterin and also mediates the stimulatory effect of phenylalanine on the enzyme activity . To characterize the molecular structure of GFRP, we have purified it from rat liver using an efficient step of affinity chromatography and isolated cDNA clones, based on partial amino acid sequences of peptides derived from purified GFRP . Comparison between the amino acid sequence deduced from the cDNA and the N-terminal amino acid sequence of purified GFRP showed that the mature form of GFRP consists of 83 amino acid residues with a calculated Mr of 9,542 . The isolated GFRP cDNA was expressed in Escherichia coli as a fusion protein with six consecutive histidine residues at its N terminus . The fusion protein was affinity-purified and digested with thrombin to remove the histidine tag . The resulting recombinant GFRP showed kinetic properties similar to those of GFRP purified from rat liver . Cross-linking experiments using dimethyl suberimidate indicated that GFRP was a pentamer of 52 kDa . Sedimentation equilibrium measurements confirmed the pentameric structure of GFRP by giving an average Mr of 49,734, which is 5 times the calculated molecular weight of the recombinant GFRP polypeptide . Based on the pentameric structure of GFRP, we have proposed a model for the quaternary structure of GFRP and GTP cyclohydrolase I complexes.

Turk J Pediatr, 1997 Apr-Jun, 39(2), 177 - 84
Tumor necrosis factor-alpha and interleukin-1 beta levels in children with bacterial, tuberculous and aseptic meningitis; Ceyhan M et al.; Cerebrospinal fluid levels of tumor necrosis factor-alpha and interleukin-1 beta in 78 children with nonbacterial, bacterial and tuberculous meningitis, and in 34 control subjects were analyzed in order to evaluate the involvement of these cytokines in the pathogenesis of acute bacterial meningitis and their discriminative value between different etiologies of meningitis . Tumor necrosis factor-alpha and interleukin-1 beta levels were significantly higher in bacterial and tuberculous meningitis than in aseptic meningitis and in control subjects (p < 0.0001) . There was no difference in the levels of tumor necrosis factor-alpha and interleukin-1 beta between nonbacterial meningitis and control groups . The finding that both tumor necrosis factor-alpha and interleukin-1 beta are increased in the cerebrospinal fluid of patients with bacterial and tuberculous meningitis whereas normal levels of these two cytokines have been found in patients with nonbacterial meningitis signifies that these cytokines may be used to differentiate between bacterial and nonbacterial meningitis.

Arch Oral Biol, 1997 Apr, 42(4), 255 - 62
5 alpha reductase activity in human gingiva and gingival fibroblasts in response to bacterial culture supernatants, using {14C}4-androstenedione as substrate; Soory M et al.; 5 alpha-Reduction of androgen substrates is increased in inflamed gingiva . It was therefore relevant to study the effect of bacterial culture supernatants derived from Prevotella intermedius (P.i), Porphyromonas gingivalis (P.g) and Actinobacillus actinomycetemcomitans (A.a) on the metabolism of {14C}4-androstenedione to 5 alpha-dihydrotestosterone (DHT) in gingival tissue and cultured fibroblasts . Chronically inflamed human gingival tissue and cultured gingival fibroblasts from the same source were incubated in duplicate with {14C}4-androstenedione and optimal concentrations of P.i, P.g . and A.a culture supernatants in Eagle's minimal essential medium in a CO2 incubator for 24 h at 37 degrees C . The metabolites were then extracted, separated and quantified using a radioisotope scanner . There were 87, 50 and 6% increases in DHT synthesis by human gingival tissue in response to the culture supernatants of P.i, P.g and A.a, respectively, over control incubations (n = 3; p < 0.01: Wilcoxon signed-ranked statistic for paired observations) . With the cells in culture, all four fibroblast cell lines produced DHT and testosterone from {14C}4-androstenedione in varying amounts . The production of DHT was enhanced in the presence of each the bacterial culture supernatants to varying degrees (P.i 40%, P.g 35% and A.a 40%; p < 0.01) . Combinations of the bacterial extracts: (P.i + P.g), (P.i + A.a), (P.g + A.a) and (P.i + P.g + A.a) showed intermediate or suppressor effects on DHT formed compared with individual incubations . Culture supernatants of these pathogens can influence DHT synthesis in fibroblasts, and effect that is modulated by baseline androgen metabolism and the proportion of virulent pathogens present . This may have some bearing on host susceptibility on host and the progression of the periodontal lesion.

Acta Virol, 1997 Apr, 41(2), 65 - 70
Combined protective effect of an immunostimulatory bacterial preparation and rimantadine in experimental influenza A virus infection; Serkedjieva J et al.; The protective effect of an immunostimulatory bacterial preparation, cytoplasmic membranes of Escherichia coli WF stable protoplast type L-forms (CM) alone and in combination with the selective antiviral drug rimantadine was evaluated in experimental influenza A/Aichi/2/68 (H3N2) virus infection in mice . In sublethal infection, CM administered intraperitoneally (i.p.) 7 days before virus exposure in a single dose of 25 mg/kg did not reduce significantly the virus lung titers . In lethal infection, CM applied in the same way weakly reduced the mortality rate . The combined application of CM with rimantadine resulted in synergistically increased protection, determined on the basis of virus lung titers, lung consolidation, mortality rates, protective indices, and survival times.

J Surg Res, 1997 Apr, 69(1), 178 - 82
An in vitro model to assess mucosal immune function and bacterial translocation; Diebel LN et al.; The importance of secretory immunoglobulin A (IgA) on intestinal barrier function has gained increasing acceptance . However, due to the complexity of the intestinal microenvironment, the relative role of secretory IgA (sIgA) in mucosal defense has been difficult to study in vivo . Polarized Madin-Darby canine kidney (MDCK) epithelial cells expressing the complementary DNA (cDNA) for the polymeric Ig receptor were grown as monolayers in an in vitro two-chamber cell culture system to study the impact of sIgA on bacterial translocation (BT) . Polymeric sIgA or media alone was added to the apical chambers of cell monolayers followed by apical inoculation with bacteria . The basal compartment was sampled at timed intervals thereafter to determine BT . Bacterial passage across the MDCK epithelial cell monolayers occurred in a time and bacterial inoculum concentration gradient . Addition of sIgA led to significant reductions in BT across the epithelial cell monolayers . This is a useful model for further investigation on the role of sIgA in intestinal barrier function.

Protein Eng, 1997 Apr, 10(4), 445 - 53
Two amino acid mutations in an anti-human CD3 single chain Fv antibody fragment that affect the yield on bacterial secretion but not the affinity; Kipriyanov SM et al.; Recombinant antibody fragments directed against cell surface antigens have facilitated the development of novel therapeutic agents . As a first step in the creation of cytotoxic immunoconjugates, we constructed a single-chain Fv fragment derived from the murine hybridoma OKT3, that recognizes an epitope on the epsilon-subunit of the human CD3 complex . Two amino acid residues were identified that are critical for the high level production of this scFv in Escherichia coli . First, the substitution of glutamic acid encoded by a PCR primer at position 6 of VH framework 1 by glutamine led to a more than a 30-fold increase in the production of soluble scFv . Second, the substitution of cysteine by a serine in the middle of CDR-H3 additionally doubled the yield of soluble antibody fragment without any adverse effect on its affinity for the CD3 antigen . The double mutant scFv (Q,S) proved to be very stable in vitro: no loss of activity was observed after storage for 1 month at 4 degrees C, while the activity of scFv containing a cysteine residue in CDR-H3 decreased by more than half . The results of production yield, affinity, stability measurements and analysis of three-dimensional models of the structure suggest that the sixth amino acid influences the correct folding of the VH domain, presumably by affecting a folding intermediate, but has no effect on antigen binding.

Mol Microbiol, 1997 Apr, 24(2), 241 - 8
Dynamic bacterial genome organization; Kolsto AB; Recently completed projects of sequencing chromosomal fragments and entire chromosomes, as well as physical mapping of genomes, have opened novel inroads to the understanding of the biology of bacterial genomes . From these studies one may draw some conclusions . (i) The organization of orthologous genes on the bacterial chromosome is not conserved during evolution . (ii) The bacterial genome is more complex and also more flexible than hitherto thought . Genetic elements are sometimes part of the chromosome, while at other times they are independent elements or parts of alternative replicons (e.g . large plasmids) . Such replicons, carrying essential genes, now seem to deserve the designation 'secondary chromosomes' . A study of the regulation of replication and segregation of these essential genetic elements will be of great interestPublication Types:

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