Angew Chem Int Ed Engl, 2001 Aug 3, 40(15), 2782 - 2807 Dioxygen Activation and Methane Hydroxylation by Soluble Methane Monooxygenase: A Tale of Two Irons and Three Proteins A list of abbreviations can be found in Section 7 . Merkx M, Kopp DA, Sazinsky MH, Blazyk JL, Muller J, Lippard SJ. Methanotrophic bacteria are capable of using methane as their sole source of carbon and energy . The first step in methane metabolism, the oxidation of methane to methanol, is catalyzed by a fascinating enzyme system called methane monooxygenase (MMO) . The selective oxidation of the very stable C-H bond in methane under ambient conditions is a remarkable feat that has not yet been repeated by synthetic catalysts and has attracted considerable scientific and commercial interest . The best studied MMO is a complex enzyme system that consists of three soluble protein components, all of which are required for efficient catalysis . Dioxygen activation and subsequent methane hydroxylation are catalyzed by a hydroxylase enzyme that contains a non-heme diiron site . A reductase protein accepts electrons from NADH and transfers them to the hydroxylase where they are used for the reductive activation of O(2) . The third protein component couples electron and dioxygen consumption with methane oxidation . In this review we examine different aspects of catalysis by the MMO proteins, including the mechanisms of dioxygen activation at the diiron site and substrate hydroxylation by the activated oxygen species . We also discuss the role of complex formation between the different protein components in regulating various aspects of catalysis. Cytometry, 2001 Aug 1, 44(4), 361 - 8 Fluorescence resonance energy transfer analysis of cell surface receptor interactions and signaling using spectral variants of the green fluorescent protein; Chan FK et al.; BACKGROUND: Fluorescence resonance energy transfer (FRET) is a powerful technique for measuring molecular interactions at Angstrom distances . We present a new method for FRET that utilizes the unique spectral properties of variants of the green fluorescent protein (GFP) for large-scale analysis by flow cytometry . METHODS: The proteins of interest are fused in frame separately to the cyan fluorescent protein (CFP) or the yellow fluorescent protein (YFP) . FRET between these differentially tagged fusion proteins is analyzed using a dual-laser FACSVantage cytometer . RESULTS: We show that homotypic interactions between individual receptor chains of tumor necrosis factor receptor (TNFR) family members can be detected as FRET from CFP-tagged receptor chains to YFP-tagged receptor chains . Noncovalent molecular complexation can be detected as FRET between fusions of CFP and YFP to either the intracellular or extracellular regions of the receptor chains . The specificity of the assay is demonstrated by the absence of FRET between heterologous receptor pairs that do not biochemically associate with each other . Interaction between a TNFR-like receptor (Fas/CD95/Apo-1) and a downstream cytoplasmic signaling component (FADD) can also be demonstrated by flow cytometric FRET analysis . CONCLUSIONS: The utility of spectral variants of GFP in flow cytometric FRET analysis of membrane receptors is demonstrated . This method of analyzing FRET allows probing of noncovalent molecular interactions that involve both the intracellular and extracellular regions of membrane proteins as well as proteins within the cells . Unlike biochemical methods, FRET allows the quantitative determination of noncovalent molecular associations at Angstrom level in living cells . Moreover, flow cytometry allows quantitative analyses to be carried out on a cell-by-cell basis on large number of cells . Published 2001 Wiley-Liss, Inc. Mem Inst Oswaldo Cruz, 2001 Jul, 96(5), 723 - 8 Biological activities of Curcuma longa L; Araujo CC et al.; There are several data in the literature indicating a great variety of pharmacological activities of Curcuma longa L . (Zingiberaceae), which exhibit anti-inflammatory, anti-human immunodeficiency virus, anti-bacteria, antioxidant effects and nematocidal activities . Curcumin is a major component in Curcuma longa L., being responsible for its biological actions . Other extracts of this plant has been showing potency too . In vitro, curcumin exhibits anti-parasitic, antispasmodic, anti-inflammatory and gastrointestinal effects; and also inhibits carcinogenesis and cancer growth . In vivo, there are experiments showing the anti-parasitic, anti-inflammatory potency of curcumin and extracts of C . longa L . by parenteral and oral application in animal models . In this present work we make an overview of the pharmacological activities of C . longa L., showing its importance. Saudi Med J, 2000 Jun, 21(6), 569 - 73 Ultrastructural study of the gastric mucosa and Helicobacter pylori in duodenal ulcer patients; Al-Muhtaseb MH et al.; OBJECTIVE: To investigate the relationship between Helicobacter pylori and gastric mucosa in control and duodenal ulcer patients at the electron microscopic level . METHODS: Three antral biopsies were taken from each of 20 normal control volunteers and 30 duodenal ulcer patients presented to the gastroenterology unit at Jordan University Hospital for upper endoscopic examination . Each specimen was fixed and processed for electron microscopic study . RESULTS: Two types of Helicobacter pylori were observed and identified by their morphology at electron microscopy . The first one was characterized by double external smooth membranes and homogeneous cytoplasmic contents, and the second type with a characteristic ring-shaped intracytoplasmic vacuole . Electron microscopic examination of normal controls showed normal gastric mucosa and a small number of Helicobacter pylori in 12 out of 20 controls . However, in duodenal ulcer patients, 5 different patterns of interaction between the Helicobacter pylori and gastric mucosa were observed in relation to the severity of the disease . In duodenal ulcer patients, various types of epithelial damage was seen accompanied with a decrease or absence of mucous secretion and with more colonization of bacteria . CONCLUSION: The morphology and pathogenesis of Helicobacter pylori was described in duodenal ulcer patients, and 5 different patterns of contact between Helicobacter pylori and surface epithelium were recognized causing variable degrees of microvillous atrophy and reduced mucous secretion . The vacuolated type of Helicobacter pylori was more adherent to the damaged epithelium and there was a direct relationship between the epithelial damage and bacterial load . In the normal controls, no epithelial damage and scanty bacteria were observed . The various types of epithelial changes of gastric mucosa has initiated more research at electron microscopic level on the immune mechanism of the gastric mucosa to determine the underlying cause of the varying severity of the disease. Plant Physiol, 2001 Aug, 126(4), 1358 - 69 The complete set of genes encoding major intrinsic proteins in Arabidopsis provides a framework for a new nomenclature for major intrinsic proteins in plants; Johanson U et al.; Major intrinsic proteins (MIPs) facilitate the passive transport of small polar molecules across membranes . MIPs constitute a very old family of proteins and different forms have been found in all kinds of living organisms, including bacteria, fungi, animals, and plants . In the genomic sequence of Arabidopsis, we have identified 35 different MIP-encoding genes . Based on sequence similarity, these 35 proteins are divided into four different subfamilies: plasma membrane intrinsic proteins, tonoplast intrinsic proteins, NOD26-like intrinsic proteins also called NOD26-like MIPs, and the recently discovered small basic intrinsic proteins . In Arabidopsis, there are 13 plasma membrane intrinsic proteins, 10 tonoplast intrinsic proteins, nine NOD26-like intrinsic proteins, and three small basic intrinsic proteins . The gene structure in general is conserved within each subfamily, although there is a tendency to lose introns . Based on phylogenetic comparisons of maize (Zea mays) and Arabidopsis MIPs (AtMIPs), it is argued that the general intron patterns in the subfamilies were formed before the split of monocotyledons and dicotyledons . Although the gene structure is unique for each subfamily, there is a common pattern in how transmembrane helices are encoded on the exons in three of the subfamilies . The nomenclature for plant MIPs varies widely between different species but also between subfamilies in the same species . Based on the phylogeny of all AtMIPs, a new and more consistent nomenclature is proposed . The complete set of AtMIPs, together with the new nomenclature, will facilitate the isolation, classification, and labeling of plant MIPs from other species. Infect Immun, 2001 Sep, 69(9), 5857 - 63 In vivo and in vitro studies of cytosolic phospholipase A2 expression in Helicobacter pylori infection; Nardone G et al.; Modifications of mucosal phospholipids have been detected in samples from patients with Helicobacter pylori-positive gastritis . These alterations appear secondary to increased phospholipase A2 activity (PLA2) . The cytosolic form of this enzyme (cPLA2), normally involved in cellular signaling and growth, has been implicated in cancer pathogenesis . The aim of this study was to investigate cPLA2 expression and PLA2 activity in the gastric mucosae of patients with and without H . pylori infection . In gastric biopsies from 10 H . pylori-positive patients, cPLA2 levels, levels of mRNA as determined by reverse transcriptase PCR, levels of protein as determined by immunohistochemistry, and total PLA2 activity were higher than in 10 H . pylori-negative gastritis patients . To clarify whether H . pylori had a direct effect on the cellular expression of cPLA2, we studied cPLA2 expression in vitro with different human epithelial cell lines, one from a patient with larynx carcinoma (i.e., HEp-2 cells) and two from patients with gastric adenocarcinoma (i.e., AGS and MKN 28 cells), incubated with different H . pylori strains . The levels of cPLA2, mRNA, and protein expression were unchanged in Hep-2 cells independently of cellular adhesion or invasion of the bacteria . Moreover, no change in cPLA2 protein expression was observed in AGS or MKN 28 cells treated with wild-type H . pylori . In conclusion, our study shows increased cPLA2 expression and PLA2 activity in the gastric mucosae of patients with H . pylori infection and no change in epithelial cell lines exposed to H . pylori. Infect Immun, 2001 Sep, 69(9), 5777 - 85 Identification and characterization of mycobacterial proteins differentially expressed under standing and shaking culture conditions, including Rv2623 from a novel class of putative ATP-binding proteins; Florczyk MA et al.; The environmental signals that affect gene regulation in Mycobacterium tuberculosis remain largely unknown despite their importance to tuberculosis pathogenesis . Other work has shown that several promoters, including acr (also known as hspX) (alpha-crystallin homolog), are upregulated in shallow standing cultures compared with constantly shaking cultures . Each of these promoters is also induced to a similar extent within macrophages . The present study used two-dimensional gel electrophoresis and mass spectrometry to further characterize differences in mycobacterial protein expression during growth under standing and shaking culture conditions . Metabolic labeling of M . bovis BCG showed that at least 45 proteins were differentially expressed under standing and shaking culture conditions . Rv2623, CysA2-CysA3, Gap, and Acr were identified from each of four spots or gel bands that were specifically increased in bacteria from standing cultures . An additional standing-induced spot contained two comigrating proteins, GlcB and KatG . The greatest induction was observed with Rv2623, a 32-kDa protein of unknown function that was strongly expressed under standing conditions and absent in shaking cultures . Analysis using PROBE, a multiple sequence alignment and database mining tool, classified M . tuberculosis Rv2623 as a member of a novel class of ATP-binding proteins that may be involved in M . tuberculosis's response to environmental signals . These studies demonstrate the power of combined proteomic and computational approaches and demonstrate that subtle differences in bacterial culture conditions may have important implications for the study of gene expression in mycobacteria. Infect Immun, 2001 Sep, 69(9), 5752 - 9 Cytolethal distending toxin demonstrates genotoxic activity in a yeast model; Hassane DC et al.; Cytolethal distending toxins (CDTs) are multisubunit proteins produced by a variety of bacterial pathogens that cause enlargement, cell cycle arrest, and apoptosis in mammalian cells . While their function remains uncertain, recent studies suggest that they can act as intracellular DNases in mammalian cells . Here we establish a novel yeast model for understanding CDT-associated disease . Expression of the CdtB subunit in yeast causes a G2/M arrest, as seen in mammalian cells . CdtB toxicity is not circumvented in yeast genetically altered to lack DNA damage checkpoint control or that constitutively promote cell cycle progression via mutant Cdk1, because CdtB causes a permanent type of damage that results in loss of viability . Finally, we establish that CDTs are likely to be potent genotoxins, as indicated by in vivo degradation of chromosomal DNA associated with expression of CdtB-suggesting that the varied distribution of CDT in bacteria implicates many human pathogens as possessors of genotoxic activity. Infect Immun, 2001 Sep, 69(9), 5698 - 708 Porphyromonas gingivalis traffics to autophagosomes in human coronary artery endothelial cells; Dorn BR et al.; Porphyromonas gingivalis is a periodontal pathogen that also localizes to atherosclerotic plaques . Our previous studies demonstrated that P . gingivalis is capable of invading endothelial cells and that intracellular bacteria are contained in vacuoles that resemble autophagosomes . In this study, we have examined the trafficking of P . gingivalis 381 to the autophagic pathway . P . gingivalis 381 internalized by human coronary artery endothelial (HCAE) cells is located within vacuoles morphologically identical to autophagosomes . The progression of P . gingivalis 381 through intracellular vacuoles was analyzed by immunofluorescence microscopy . Vacuoles containing P . gingivalis colocalize with Rab5 and HsGsa7p early after internalization . At later times, P . gingivalis colocalizes with BiP and then progresses to a vacuole that contains BiP and lysosomal glycoprotein 120 . Late endosomal markers and the lysosomal cathepsin L do not colocalize with P . gingivalis 381 . The intracellular survival of P . gingivalis 381 decreases over 8 h in HCAE cells pretreated with the autophagy inhibitors 3-methyladenine and wortmannin . In addition, the vacuole containing P . gingivalis 381 lacks BiP but contains cathepsin L in the presence of wortmannin . These results suggest that P . gingivalis 381 evades the endocytic pathway to lysosomes and instead traffics to the autophagosome. Infect Immun, 2001 Sep, 69(9), 5661 - 70 Production of matrix metalloproteinases in response to mycobacterial infection; Quiding-Jarbrink M et al.; Matrix metalloproteinases (MMPs) constitute a large family of enzymes with specificity for the various proteins of the extracellular matrix which are implicated in tissue remodeling processes and chronic inflammatory conditions . To investigate the role of MMPs in immunity to mycobacterial infections, we incubated murine peritoneal macrophages with viable Mycobacterium bovis BCG or Mycobacterium tuberculosis H37Rv and assayed MMP activity in the supernatants by zymography . Resting macrophages secreted only small amounts of MMP-9 (gelatinase B), but secretion increased dramatically in a dose-dependent manner in response to either BCG or M . tuberculosis in vitro . Incubation with mycobacteria also induced increased MMP-2 (gelatinase A) activity . Neutralization of tumor necrosis alpha (TNF-alpha), and to a lesser extent interleukin 18 (IL-18), substantially reduced MMP production in response to mycobacteria . Exogenous addition of TNF-alpha or IL-18 induced macrophages to express MMPs, even in the absence of bacteria . The immunoregulatory cytokines gamma interferon (IFN-gamma), IL-4, and IL-10 all suppressed BCG-induced MMP production, but through different mechanisms . IFN-gamma treatment increased macrophage secretion of TNF-alpha but still reduced their MMP activity . Conversely, IL-4 and IL-10 seemed to act by reducing the amount of TNF-alpha available to the macrophages . Finally, infection of BALB/c or severe combined immunodeficiency (SCID) mice with either BCG or M . tuberculosis induced substantial increases in MMP-9 activity in infected tissues . In conclusion, we show that mycobacterial infection induces MMP-9 activity both in vitro and in vivo and that this is regulated by TNF-alpha, IL-18, and IFN-gamma . These findings indicate a possible contribution of MMPs to tissue remodeling processes that occur in mycobacterial infections. Infect Immun, 2001 Sep, 69(9), 5417 - 22 Ontogeny of Th1 memory responses against a Brucella abortus conjugate; Scharf O et al.; Protective immune responses to intracellular pathogens such as Brucella abortus are characteristically Th1-like . Recently we demonstrated that heat-killed B . abortus (HKBa), a strong Th1 stimulus, conjugated to ovalbumin (HKBA-OVA), but not B . abortus alone, can alter the antigen-specific cytokine profile from Th2- to Th1-like . In this report we study the ability of a single injection of B . abortus to switch a Th2 to a Th1 response in immature mice . One-day- and 1-week-old mice were given a single injection of B . abortus in the absence or presence of OVA, and at maturity mice were challenged with an allergenic preparation, OVA with alum (OVA-A) . B . abortus given without OVA did not diminish the subsequent Th2 response in either age group . In contrast, mice receiving a single injection of B . abortus-OVA at the age of 1 week, but not those injected at the age of 1 day, had reversal of the ratio of OVA-specific Th1 to Th2 cells and decreased immunoglobulin E levels after allergen challenge as adults . Within 6 h both 1-day- and 1-week-old mice expressed interleukin-12 p40 mRNA following either B . abortus or B . abortus-OVA administration . However, only the 1-week-old mice exhibited increased expression of gamma interferon (IFN-gamma) mRNA . The absence of the early IFN-gamma response in 1-day-old mice may explain their inability to generate a Th1 memory response . These results suggest that at early stages of immune development, responses to intracellular bacteria may be Th2- rather than Th1-like . Furthermore, they suggest that the first encounter with antigen evokes either a Th1- or a Th2-like response which becomes imprinted, so that subsequent memory responses conform to the original Th bias . This has implications for protection against infectious agents and development of allergic responses. Infect Immun, 2001 Sep, 69(9), 5286 - 93 Borrelia burgdorferi RevA antigen is a surface-exposed outer membrane protein whose expression is regulated in response to environmental temperature and pH; Carroll JA et al.; Borrelia burgdorferi, the causative agent of Lyme disease, produces RevA protein during the early stages of mammalian infection . B . burgdorferi apparently uses temperature as a cue to its location, producing proteins required for infection of warm-blooded animals at temperatures corresponding to host body temperature, but does not produce such virulence factors at cooler, ambient temperatures . We have observed that B . burgdorferi regulates expression of RevA in response to temperature, with the protein being synthesized by bacteria cultivated at 34 degrees C but not by those grown at 23 degrees C . Tissues encountered by B . burgdorferi during its infectious cycle vary in their pH values, and the level of RevA expression was also found to be dependent upon pH of the culture medium . The cellular localization of RevA was also analyzed . Borrelial inner and outer membranes were purified by isopycnic centrifugation, and membrane fractions were conclusively identified by immunoblot analysis using antibodies raised against the integral inner membrane protein MotB and outer membrane-associated Erp lipoproteins . Immunoblot analyses indicated that RevA is located in the B . burgdorferi outer membrane . These analyses also demonstrated that an earlier report (H . A . Bledsoe et al., Infect . Immun . 176:7447-7455, 1994) had misidentified such B . burgdorferi membrane fractions . RevA was further demonstrated to be exposed to the external environment, where it could facilitate interactions with host tissues. EMBO J, 2001 Aug 15, 20(16), 4341 - 8 The Dictyostelium homologue of mammalian soluble adenylyl cyclase encodes a guanylyl cyclase; Roelofs J et al.; A new Dictyostelium discoideum cyclase gene was identified that encodes a protein (sGC) with 35% similarity to mammalian soluble adenylyl cyclase (sAC) . Gene disruption of sGC has no effect on adenylyl cyclase activity and results in a >10-fold reduction in guanylyl cyclase activity . The scg- null mutants show reduced chemotactic sensitivity and aggregate poorly under stringent conditions . With Mn(2+)/GTP as substrate, most of the sGC activity is soluble, but with the more physiological Mg(2+)/GTP the activity is detected in membranes and stimulated by GTPgammaS . Unexpectedly, orthologues of sGC and sAC are present in bacteria and vertebrates, but absent from Drosophila melanogaster, Caenorhabditis elegans, Arabidopsis thaliana and Saccharomyces cerevisiae. J Biotechnol, 2001 Aug 23, 89(2-3), 155 - 62 Batch tests for assessing decolourisation of azo dyes by methanogenic and mixed cultures; Bras R et al.; Most of the published studies on azo dye colour removal involve anaerobic mixed cultures and there is some interest in the knowledge of how dye reduction occurs, if by facultative, strictly anaerobic or both bacterial trophic groups present in classic anaerobic digestors . This paper describes the behaviour of methanogenic and mixed bacteria cultures on the colour removal in batch systems, of a commercial azo dye, C.I . Acid Orange 7, used in paper and textile industries . The aim of this study is to demonstrate, by analysing dye decolourisation, that it occurs with mixed cultures as well as with strictly anaerobic (methanogenic) cultures . Tests were performed with a range of dye concentrations between 60 and 300 mg x l(-1) . The influence of dye concentration on the carbon source removal and decolourisation processes was studied . The effect of carbon source concentration on colour removal was also analysed for both cultures . The degradation rates in mixed and methanogenic cultures were compared . The consumption of carbon source was monitored by COD analysis and dye degradation by ultraviolet-visible spectrophotometry and thin layer chromatography. Transfus Clin Biol, 2001 Jun, 8(3), 163 - 99 Structural and functional diversity of blood group antigens; Cartron JP et al.; Biochemical and molecular genetic studies have revealed that blood group antigens are present on cell surface molecules of wide structural diversity, including carbohydrate epitopes on glycoproteins and/or glycolipids, and peptide antigens on proteins inserted within the membrane via single or multi-pass transmembrane domains, or via glycosylphosphatidylinositol linkages . These studies have also shown that some blood group antigens are carried by complexes consisting of several membrane components which may be lacking or severely deficient in rare blood group 'null' phenotypes . In addition, although all blood group antigens are serologically detectable on red blood cells (RBCs), most of them are also expressed in non-erythroid tissues, raising further questions on their physiological function under normal and pathological conditions . In addition to their structural diversity, blood group antigens also possess wide functional diversity, and can be schematically subdivided into five classes: i) transporters and channels; ii) receptors for ligands, viruses, bacteria and parasites; iii) adhesion molecules; iv) enzymes; and v) structural proteins . The purpose of this review is to summarize recent findings on these molecules, and in particular to illustrate the existing structure-function relationships. Transfus Clin Biol, 2001 Jun, 8(3), 138 - 45 Inactivation of infectious pathogens in labile blood components: meeting the challenge; Corash L; Substantial improvement in the safety of blood transfusion has been achieved through the addition of new tests, such as nucleic acid tests, yet residual risk associated with transfusion of blood components persists . Transfusion of blood components has been implicated in the transmission of viruses, bacteria, and protozoa . While it is commonly recognized that hepatitis B virus (HBV), hepatitis C virus (HCV), cytomegalovirus (CMV), and the retroviruses, such as human immunodeficiency virus (HIV) and the human lymphotrophic viruses (HTLV) can be transmitted through cellular components, other pathogens are emerging as potentially significant transfusion-associated infectious agents . For example, transmission of protozoan infections due to trypanosomes and babesia have been reported . In addition to viral and protozoal infectious agents, bacterial contamination of platelet and red cell concentrates continues to be reported; and may be an under-reported transfusion complication . More importantly, new infectious agents may periodically enter the donor population before they can be definitively identified and tested for to maintain consistent safety of the blood supply . The paradigm for this possibility is the HIV pandemic, which erupted in 1979 . During the past decade a number of methods to inactivate infectious pathogens in labile blood components have been developed and have entered the advanced clinical trial phase. Biochem Soc Trans, 2001 Aug, 29(Pt 4), 480 - 4 Internalization of the epidermal growth factor receptor: role in signalling; Sorkin A; The interaction of the activated epidermal growth factor (EGF) receptor (EGFR) with the Src homology 2 (SH2) domain of Grb2 (growth-factor-receptor-bound protein 2) initiates signalling through Ras and mitogen-activated protein kinase . Grb2 can bind EGFR directly or through another SH2-containing protein, Shc . Activation of EGFRs by ligand also triggers rapid endocytosis of EGF-receptor complexes . To analyse the spatial and temporal regulation of EGFR interactions with SH2 domains in living cells, we have combined imaging microscopy with a modified method of measuring fluorescence resonance energy transfer (FRET) on a pixel-by-pixel basis using EGFR fused to cyan fluorescent protein (CFP) in pair with Grb2 or Shc fused to yellow fluorescent protein (YFP) . Stimulation by EGF resulted in the recruitment of Grb2-YFP and YFP-Shc to cellular compartments that contained EGFR-CFP, and a large increase in the FRET signal . In particular, FRET measurements indicated that activated EGFR-CFP interacted with YFP-Shc and Grb2-YFP in membrane ruffles and endosomes . These results demonstrate that signalling via EGFRs can occur in the endosomal compartment . Moreover, in contrast with previous biochemical studies, FRET experiments show that a large pool of Grb2 and Shc is associated with EGFRs for a prolonged period after EGF stimulation. Biochem Soc Trans, 2001 Aug, 29(Pt 4), 455 - 9 Auxiliary functions in photosynthesis: the role of the FtsH protease; Bailey S et al.; Oxygenic photosynthesis can be described effectively by using two long-standing models: the Z-scheme and the chemiosmotic hypothesis . However, these models do not reveal the dynamic nature of the thylakoid membrane and the four major complexes that it binds . The composition of the photosynthetic apparatus is continually changing in response to a range of environmental stimuli . In addition, many photosynthetic components have some of the highest turnover rates in Nature . Changes in composition and turnover of photosynthetic components require the degradation of existing and damaged polypeptides and the resynthesis and co-ordinated assembly of new polypeptides and their associated cofactors . This is achieved by several auxiliary functions, including proteolysis, protein targeting and the action of molecular chaperones . Some of the components involved in these functions, such as translocons, chaperones and proteases, have been identified but many of the auxiliary functions of photosynthesis remain uncharacterized . Among the proteases known to be associated with the thylakoids is the zinc metalloprotease FtsH, which might also act as a chaperone . Here we provide an overview of the thylakoid FtsH protease and discuss its role in the maintenance and assembly of the photosynthetic apparatus. Biochem Soc Trans, 2001 Aug, 29(Pt 4), 427 - 30 Degradation of unassembled and damaged thylakoid proteins; Adam Z et al.; To study protein degradation in thylakoid membranes we identified, characterized and cloned thylakoid proteases, and then linked them to known proteolytic processes . Several families of chloroplast proteases were identified and characterized to different extents . FtsH, an ATP-dependent metalloprotease that belongs to the AAA-protein family, was found to be integral to the thylakoid membrane, facing the stroma . It is involved in both the degradation of unassembled subunits of membrane complexes, such as the Rieske Fe-S protein of the cytochrome complex, and the degradation of oxidatively damaged proteins such as the D1 protein of the photosystem II (PS II) reaction centre . Plant genomes contain multiple isomers of this protease but the functional significance of this multiplication is not clear yet . A second protease, the serine ATP-independent DegP, was found to be strongly associated with the luminal side of the thylakoid membrane . Although a specific role has not yet assigned for it, its location suggests that it can degrade luminal soluble proteins as well as luminally exposed regions of thylakoid membrane proteins. Biochem Soc Trans, 2001 Aug, 29(Pt 4), 418 - 21 Incorporation of iron-sulphur clusters in membrane-bound proteins; Seidler A et al.; The completely sequenced genome of the cyanobacterium Synechocystis PCC 6803 contains several open reading frames, of which the deduced amino acid sequences show similarities to proteins known to be involved in FeS cluster synthesis of nitrogenase (Nif proteins) and other FeS proteins (Isc proteins) . In this article, the results of our studies on these proteins are summarized and discussed with respect to their relevance in FeS cluster incorporation in chloroplasts . In cyanobacteria, there appears to exist several pathways for FeS cluster synthesis. Biochem Soc Trans, 2001 Aug, 29(Pt 4), 392 - 5 Basal and regulated transcription in Archaea; Bell SD et al.; The basal transcription machinery of Archaea is fundamentally related to the eucaryal RNA polymerase (RNAP) II apparatus . In addition to a 12-subunit RNAP, Archaea possess two general transcription factors, the activities of which are required for accurate and efficient in vitro transcription . These factors, TBP and TFB, are homologues of the eucaryal TATA-box binding protein and TFIIB respectively . Archaea also possess TFE, a homologue of the eucaryal RNAP II general transcription factor TFIIE . Although not absolutely required for transcription in vitro, TFE nonetheless plays a stimulatory role under conditions where promoter recognition by TBP is sub-optimal . The basal transcription apparatus of Archaea is closely related to that of Eucarya but archaeal transcriptional regulators resemble those of bacteria . The mode of action of two such regulators has been characterized to determine how these 'bacterial-like' regulators impinge on the 'eucaryal-like' basal machinery. Nippon Yakurigaku Zasshi, 2001 Jul, 118(1), 15 - 22 {Histamine produced by macrophage and T lymphocyte: a new type of signal transducer}; Nakano K et al.; Macrophages (M phi) produce histamine (Hm) when activated by bacterial endotoxin (LPS) through induced histidine decarboxylase (HDC) . Among the cytokines tested, GM-CSF or IL-3 specifically augmented the LPS-dependent HDC induction by M phi . Hm formed by M phi regulates synthesis of cytokines such as IL-1, IL-6, G-CSF and M-CSF by the cells per se and may modulate immune reactions and division and differentiation of various hematopoietic cells . Kupffer cells, M phi-like cells in the liver, also synthesize Hm in mice injected with hepatotoxins such as tetradecanoylphorbol acetate or LPS . Hm thus produced by Kupffer cells may participate in the regeneration of the injured liver through induction of hepatocyte growth factor . Concanavalin A (Con A) enhanced Hm formation by T lymphocytes . GM-CSF or IL-3 also enhanced the Hm synthesis by CD4+ and CD8+ T cells . Hm formed by T cells regulates immune reactions such as lymphocyte blastogenesis . In animals infected with gram(-) bacteria Hm is produced by the M phi-T cell system and may regulate immune competence to the bacteria . In addition, Hm may act as a signal transducer between the peripheral immune system and hypothalamus-pituitary-adrenal system, leading to GC secretion, in order to prevent occurrence of tissue injury caused by excess immune reactions. Water Sci Technol, 2001, 44(1), 161 - 6 Sludge digestion enhancement and nutrient removal from anaerobic supernatant by Mg(OH)2 application; Wu Q et al.; Anaerobic sludge digestion is a widely adopted process for sludge stabilization . Phosphate removal from anaerobic supernatant is necessary to limit the phosphate returned to the head of the treatment plant, thereby improving the overall treatment efficiency . In this study, magnesium hydroxide (Mg(OH)2) was used to improve the sludge digestion efficiency and to remove phosphorus from anaerobic supernatant . The anaerobic sludge digestion experiment was conducted at a pilot scale, and the results showed that applying Mg(OH)2 to anaerobic sludge digester resulted in a larger reduction in SS and COD, a higher biogas production rate, a lower level of phosphate and ammonia nitrogen concentrations in the sludge supernatant and an improved sludge dewaterability . Research results at both lab scale and pilot scale on phosphorus removal from anaerobic supernatant using Mg(OH)2 showed that a high removal of phosphorus can be achieved through the addition of Mg(OH)2 . The required reaction time depends on the initial phosphorus concentration and the Mg(OH)2 dosage. J Allergy Clin Immunol, 2001 Aug, 108(2), 157 - 66 Endotoxin-stimulated innate immunity: A contributing factor for asthma; Reed CE et al.; Exposure to airborne endotoxin in infancy may protect against asthma by promoting enhanced T(H)1 response and tolerance to allergens . On the other hand, later in life, it adversely affects patients with asthma . Endotoxin binding to receptors on macrophages and other cells generates IL-12, which inhibits IgE responses . It also generates cytokines like IL-1, TNF-alpha, and IL-8, which cause inflammation . These signal transduction pathways resemble those leading to the generation of cytokines, such as IL-4, IL-13, and IL-5, which are responsible for the inflammation of IgE-mediated allergic disease . The main difference seems to be that endotoxin recruits neutrophils, but IgE recruits eosinophils, and the details of the tissue injury from these granulocytes differ . Sources of airborne endotoxin include many agricultural dusts, aerosols from contaminated water in many industrial plants, contaminated heating and air-conditioning systems, mist-generating humidifiers, and damp or water-damaged homes . Acute inhalation of high concentrations of endotoxin can cause fever, cough, and dyspnea . Chronic inhalation of lesser amounts causes chronic bronchitis and emphysema and is associated with airway hyperresponsiveness . Airborne endotoxin adversely affects patients with asthma in 3 ways: (1) by increasing the severity of the airway inflammation; (2) by increasing the susceptibility to rhinovirus-induced colds; and (3) by causing chronic bronchitis and emphysema with development of irreversible airway obstruction after chronic exposure of adults . The most effective management is mitigating exposure . The potential of drug treatments requires further clinical investigation. Microbiology, 2001 Aug, 147(Pt 8), 2293 - 305 cDNA-RNA subtractive hybridization reveals increased expression of mycocerosic acid synthase in intracellular Mycobacterium bovis BCG; Li MS et al.; Identifying genes that are differentially expressed by Mycobacterium bovis BCG after phagocytosis by macrophages will facilitate the understanding of the molecular mechanisms of host cell-intracellular pathogen interactions . To identify such genes a cDNA-total RNA subtractive hybridization strategy has been used that circumvents the problems both of limited availability of bacterial RNA from models of infection and the high rRNA backgrounds in total bacterial RNA . The subtraction products were used to screen a high-density gridded Mycobacterium tuberculosis genomic library . Sequence data were obtained from 19 differential clones, five of which contained overlapping sequences for the gene encoding mycocerosic acid synthase (mas) . Mas is an enzyme involved in the synthesis of multi-methylated long-chain fatty acids that are part of phthiocerol dimycocerosate, a major component of the complex mycobacterial cell wall . Northern blotting and primer extension data confirmed up-regulation of mas in intracellular mycobacteria and also revealed a putative extended -10 promoter structure and a long untranslated upstream region 5' of the mas transcripts, containing predicted double-stranded structures . Furthermore, clones containing overlapping sequences for furB, groEL-2, rplE and fadD28 were identified and the up-regulation of these genes was confirmed by Northern blot analysis . The cDNA-RNA subtractive hybridization enrichment and high density gridded library screening, combined with selective extraction of bacterial mRNA represents a valuable approach to the identification of genes expressed during intra-macrophage residence for bacteria such as M . bovis BCG and the pathogenic mycobacterium, M . tuberculosis. Microbiology, 2001 Aug, 147(Pt 8), 2285 - 92 Characterization of the low-pH responses of Helicobacter pylori using genomic DNA arrays; Allan E et al.; Helicobacter pylori is unique among bacterial pathogens in its ability to persist in the acidic environment of the human stomach . To identify H . pylori genes responsive to low pH, the authors assembled a high-density array of PCR-amplified random genomic DNA . Hybridization of radiolabelled cDNA probes, prepared using total RNA from bacteria exposed to buffer at either pH 4.0 or pH 7.0, allowed both qualitative and quantitative information on differential gene expression to be obtained . A previously described low-pH-induced gene, cagA, was identified together with several novel genes that may have relevance to the survival and persistence of H . pylori in the gastric environment . These include genes encoding enzymes involved in LPS and phospholipid synthesis and secF, encoding a component of the protein export machinery . A hypothetical protein unique to H . pylori (HP0681) was also found to be acid induced . Genes down-regulated at pH 4.0 include those encoding a sugar nucleotide biosynthesis protein, a flagellar protein and an outer-membrane protein . Differential gene expression was confirmed by total RNA slot-blot hybridization. Microbiology, 2001 Aug, 147(Pt 8), 2265 - 73 SigB, an alternative sigma factor of the myxobacterium Stigmatella aurantiaca, is synthesized during development and heat shock; Silakowski B et al.; Alternative sigma factors have been detected in the myxobacterium Stigmatella aurantiaca during indole-induced sporulation, fruiting body formation and heat shock using an antiserum raised against sigma factor SigB . The time course of sigB gene expression was analysed by RT-PCR and by determining beta-galactosidase activity during development in a merodiploid strain that harboured a sigB-lacZ fusion gene . Inactivation of the sigB gene by insertion of the neo gene resulted in the loss of one sigma factor as shown by Western analysis . Neither fruiting body formation nor sporulation, nor the production of possible SigB targets, such as DnaK, GroEL or HspA, were affected. Microbiology, 2001 Aug, 147(Pt 8), 2141 - 8 Molecular characterization of a deletion/duplication rearrangement in tfd genes from Ralstonia eutropha JMP134(pJP4) that improves growth on 3-chlorobenzoic acid but abolishes growth on 2,4-dichlorophenoxyacetic acid; Clement P et al.; Ralstonia eutropha JMP134(pJP4) is able to grow on minimal media containing the pollutants 3-chlorobenzoate (3-CB) or 2,4-dichlorophenoxyacetate (2,4-D) . tfd genes from the 88 kb plasmid pJP4 encode enzymes involved in the degradation of these compounds . During growth of strain JMP134 in liquid medium containing 3-CB, a derivative strain harbouring a approximately 95 kb plasmid was isolated . This derivative, designated JMP134(pJP4-F3), had an improved ability to grow on 3-CB, but had lost the ability to grow on 2,4-D . Sequence analysis of pJP4-F3 indicated that the plasmid had undergone a deletion of approximately 16 kb, which included the tfdA-tfdS intergenic region, spanning the tfdA gene to a previously unreported IS1071 element . The loss of the tfdA gene explains the failure of the derivative to grow on 2,4-D . A approximately 23 kb duplication of the region spanning tfdR-tfdD(II)C(II)E(II)F(II)-tfdB(II)-tfdK-ISJP4-tfdT-tfdC(I)D(I)E(I)F(I)-tfdB(I), giving rise to a 51-kb-long inverted repeat, was also observed . The increase in gene copy number for the tfdCD(DC)EF gene cluster may provide an explanation for the derivative strain's improved growth on 3-CB . These observations are additional examples of the metabolic plasticity of R . eutropha JMP134, one of the more versatile pollutant-degrading bacteria. Curr Opin Microbiol, 2001 Aug, 4(4), 435 - 41 Interactions between rotavirus and gastrointestinal cells; Ciarlet M et al.; Rotaviruses are the leading cause of life-threatening diarrheal disease in infants and in young animals worldwide . The outcome of rotavirus infection of intestinal epithelial cells is more complex and involves induction of more diverse cellular responses than initially appreciated . Similar to bacteria, the pathogenesis of rotavirus-induced disease involves an enterotoxin, activation of the enteric nervous system and malabsorption, suggesting that common mechanisms of pathogenesis may exist between viral and bacterial pathogens. Curr Opin Struct Biol, 2001 Aug, 11(4), 420 - 6 Crystal structure of rhodopsin: implications for vision and beyond; Okada T et al.; A heptahelical transmembrane bundle is a common structural feature of G-protein-coupled receptors (GPCRs) and bacterial retinal-binding proteins, two functionally distinct groups of membrane proteins . Rhodopsin, a photoreceptor protein involved in photopic (rod) vision, is a prototypical GPCR that contains 11-cis-retinal as its intrinsic chromophore ligand . Therefore, uniquely, rhodopsin is a GPCR and also a retinal-binding protein, but is not found in bacteria . Rhodopsin functions as a typical GPCR in processes that are triggered by light and photoisomerization of its ligand . Bacteriorhodopsin is a light-driven proton pump with an all-trans-retinal chromophore that photoisomerizes to 13-cis-retinal . The recent crystal structure determination of bovine rhodopsin revealed a structure that is not similar to previously established bacteriorhodopsin structures . Both groups of proteins have a heptahelical transmembrane bundle structure, but the helices are arranged differently . The activation of rhodopsin involves rapid cis-trans photoisomerization of the chromophore, followed by slower and incompletely defined structural rearrangements . For rhodopsin and related receptors, a common mechanism is predicted for the formation of an active state intermediate that is capable of interacting with G proteins. Curr Opin Struct Biol, 2001 Aug, 11(4), 408 - 14 Potassium channels: life in the post-structural world; Minor DL Jr; More than three years have passed since the first structure of a potassium channel protein revealed fundamental molecular details of a platform for ion-selective conduction . Recent efforts have turned to understanding what this structure tells us about potassium channel structure and function in general and, most importantly, which questions remain unanswered . Successes in solving membrane protein structures are still hard won and slow . High-resolution studies of cytoplasmic channel domains and channel-associated proteins, the most tractable entry points for dissecting large, complex eukaryotic channels, are revealing a modularity of function commonly seen in many other biological systems . Studies of these domains bring into sharp focus issues of channel regulation, how these domains and associated proteins are coupled to the transmembrane domains to influence channel function, and how ion channels are integrated into cellular signaling pathways. Drug Metab Rev, 2001 May, 33(2), 125 - 47 The pharmacokinetics of glycyrrhizic acid evaluated by physiologically based pharmacokinetic modeling; Ploeger B et al.; Glycyrrhizic acid is widely applied as a sweetener in food products and chewing tobacco . In addition, it is of clinical interest for possible treatment of chronic hepatitis C . In some highly exposed subjects, side effects such as hypertension and symptoms associated with electrolyte disturbances have been reported . To analyze the relationship between the pharmacokinetics of glycyrrhizic acid in its toxicity, the kinetics of glycyrrhizic acid and its biologically active metabolite glycyrrhetic acid were evaluated . Glycyrrhizic acid is mainly absorbed after presystemic hydrolysis as glycyrrhetic acid . Because glycyrrhetic acid is a 200-1000 times more potent inhibitor of 11-beta-hydroxysteroid dehydrogenase compared to glycyrrhizic acid, the kinetics of glycyrrhetic acid are relevant in a toxicological perspective . Once absorbed, glycyrrhetic acid is transported, mainly taken up into the liver by capacity-limited carriers, where it is metabolized into glucuronide and sulfate conjugates . These conjugates are transported efficiently into the bile . After outflow of the bile into the duodenum, the conjugates are hydrolyzed to glycyrrhetic acid by commensal bacteria; glycyrrhetic acid is subsequently reabsorbed, causing a pronounced delay in the terminal plasma clearance . Physiologically based pharmacokinetic modeling indicated that, in humans, the transit rate of gastrointestinal contents through the small and large intestines predominantly determines to what extent glycyrrhetic acid conjugates will be reabsorbed . This parameter, which can be estimated noninvasively, may serve as a useful risk estimator for glycyrrhizic-acid-induced adverse effects, because in subjects with prolonged gastrointestinal transit times, glycyrrhetic acid might accumulate after repeated intake. Proc Natl Acad Sci U S A, 2001 Aug 14, 98(17), 9494 - 8 Epub 2001 Aug 07. Formation of a selenium-substituted rhodanese by reaction with selenite and glutathione: possible role of a protein perselenide in a selenium delivery system; Ogasawara Y et al.; Selenophosphate is the active selenium-donor compound required by bacteria and mammals for the specific synthesis of Secys-tRNA, the precursor of selenocysteine in selenoenzymes . Although free selenide can be used in vitro for the synthesis of selenophosphate, the actual physiological selenium substrate has not been identified . Rhodanese (EC ) normally occurs as a persulfide of a critical cysteine residue and is believed to function as a sulfur-delivery protein . Also, it has been demonstrated that a selenium-substituted rhodanese (E-Se form) can exist in vitro . In this study, we have prepared and characterized an E-Se rhodanese . Persulfide-free bovine-liver rhodanese (E form) did not react with SeO(3)(2-) directly, but in the presence of reduced glutathione (GSH) and SeO(3)(2-) E-Se rhodanese was generated . These results indicate that the intermediates produced from the reaction of GSH with SeO(3)(2-) are required for the formation of a selenium-substituted rhodanese . E-Se rhodanese was stable in the presence of excess GSH at neutral pH at 37 degrees C . E-Se rhodanese could effectively replace the high concentrations of selenide normally used in the selenophosphate synthetase in vitro assay in which the selenium-dependent hydrolysis of ATP is measured . These results show that a selenium-bound rhodanese could be used as the selenium donor in the in vitro selenophosphate synthetase assay. J Biol Chem, 2001 Oct 26, 276(43), 40202 - 9 Epub 2001 Aug 07. The iota-carrageenase of Alteromonas fortis . A beta-helix fold-containing enzyme for the degradation of a highly polyanionic polysaccharide; Michel G et al.; Carrageenans are gel-forming hydrocolloids extracted from the cell walls of marine red algae . They consist of d-galactose residues bound by alternate alpha(1-->3) and beta(1-->4) linkages and substituted by one (kappa-carrageenan), two (iota-carrageenan), or three (lambda-carrageenan) sulfate-ester groups per disaccharide repeating unit . Both the kappa- and iota-carrageenan chains adopt ordered conformations leading to the formation of highly ordered aggregates of double-stranded helices . Several kappa-carrageenases and iota-carrageenases have been cloned from marine bacteria . Kappa-carrageenases belong to family 16 of the glycoside hydrolases, which essentially encompasses polysaccharidases specialized in the hydrolysis of the neutral polysaccharides such as agarose, laminarin, lichenan, and xyloglucan . In contrast, iota-carrageenases constitute a novel glycoside hydrolase structural family . We report here the crystal structure of Alteromonas fortis iota-carrageenase at 1.6 A resolution . The enzyme folds into a right-handed parallel beta-helix of 10 complete turns with two additional C-terminal domains . Glu(245), Asp(247), or Glu(310), in the cleft of the enzyme, are proposed as candidate catalytic residues . The protein contains one sodium and one chloride binding site and three calcium binding sites shown to be involved in stabilizing the enzyme structure. Br J Anaesth, 2001 Aug, 87(2), 291 - 4 Touch contamination levels during anaesthetic procedures and their relationship to hand hygiene procedures: a clinical audit; Merry AF et al.; After different methods of hand preparation, volunteers rolled segments of sterile central venous catheter between their fingertips, and bacterial transfer was evaluated by standardized quantitative culture . The number of bacteria transferred differed between methods (P<0.001) . Comparisons were made with the control group (no preparation at all; median, third quartile and maximum count=6.5, 24, 55) . Bacterial transfer was greatly increased with wet hands (1227, 1932, 3254; P<0.001) . It was reduced with a new rapid method, based on thorough drying with a combination of 10 s using a cloth towel followed by either 10 or 20 s with a hot-air towel (0, 3, 7 and 0, 4, 30, respectively; P=0.007 and 0.004, respectively) . When asked to follow their personal routines, 10 consultant anaesthetists used a range of methods . Collectively, these were not significantly better than control (7.5, 15, 55; P=0.73), and neither was an air towel alone (2.5, 15, 80; P=0.176) nor the hospital's standard procedure (0, 1, 500; P=0.035) . If hand preparation is needed, an adequate and validated method should be used, together with thorough hand drying. Blood, 2001 Aug 15, 98(4), 1226 - 30 Role of the liver in regulating numbers of circulating neutrophils; Shi J et al.; Neutrophils (polymorphonuclear leukocytes {PMNs}) carry potent destructive enzymes that can destroy invasive bacteria or damage normal tissue . PMNs have a half-life of only 6 hours in the blood, but the details of this homeostasis are unknown . In a rat model of endotoxemia, P-selectin was selectively up-regulated in hepatic sinusoids and veins where it was necessary for phagocytosis of PMNs by Kupffer cells in the liver, as opposed to the spleen or the lungs . Apoptotic PMNs appeared in the lungs and spleen only after inactivation of Kupffer cells by gadolinium chloride (GdCl(3)) . Blocking of Fas protein reduced the number of apoptotic cells in the liver; binding of annexin V to phosphatidylserine (PS) reduced the number of PMNs phagocytosed by Kupffer cells . The results support a clearance pathway in which apoptosis and phagocytosis are effected by Kupffer cells after P-selectin-mediated sequestration . (Blood . 2001;98:1226-1230) J Clin Periodontol, 2001 Sep, 28(9), 886 - 90 Prevalence of Actinobacillus actinomycetemcomitans in an ethnic adult Chinese population; Tan KS et al.; AIM: The aim of this study was to determine the prevalence and the structure of the leukotoxin promoter region of Actinobacillus actinomycetemcomitans in an ethnic Chinese population . METHOD: Subgingival plaque samples were collected from 42 patients with moderate to advanced periodontitis and 50 periodontally healthy patients . A . actinomycetemcomitans was detected directly from the crude subgingival plaque by PCR using leukotoxin gene specific primers . The presence of A . actinomycetemcomitans was determined by a single 285 bp PCR amplicon . RESULTS: A . actinomycetemcomitans was found to be present in the subgingival plaque of 68 out of a total of 92 patients examined (74%) . 29 out of the 42 periodontitis patients tested were carriers of A . actinomycetemcomitans (69%) . Among the periodontally healthy patients studied, 39 out of 50 subjects possessed the bacteria (78%) . PCR analysis of the promoter region of the ltx operon revealed that none of the 42 moderate to advanced periodontitis patients examined harboured A . actinomycetemcomitans strains with the JP2-like promoter of the ltx operon, known to enhance leukotoxin expression . 2 out of the 27 advanced periodontitis patients clinically diagnosed as suffering from rapidly progressive periodontitis were found to be carriers of the mildly toxic strain of A . actinomycetemcomitans with the characteristic 652-like promoter . CONCLUSIONS: The high prevalence of A . actinomycetemcomitans, regardless of whether the subgingival samples were analysed from patients with healthy or diseased periodontium suggests that this bacterial species is part of the normal oral flora of ethnic Chinese . Our preliminary results also suggested that subjects who harboured the mildly toxic strain of A . actinomycetemcomitans were potentially susceptible to aggressive forms of periodontitis. J Clin Periodontol, 2001 Sep, 28(9), 840 - 7 Cytokine gene expression in chronic periodontitis; Bickel M et al.; BACKGROUND: Cytokines play an important role in controlling inflammatory processes and tissue homeostasis . Periodontitis, as any other chronic inflammatory disease, results from a disarrangement of host factors, mainly cytokines and the initiating agent . Modulation of the cytokines is not only controlled by the host but also by infecting bacteria and their products . AIM: In the present study, we examined the cytokine mRNA expression profiles in six patients, each presenting sites affected with (1) severe progressive periodontitis, (2) chronic, but stable periodontal lesions, and (3) with healthy sites . Analysis using a quantitative RT-PCR included IFN-gamma, IL-1beta, IL-2, IL-4, IL-5, IL-6, and TNF-alpha . MATERIAL AND METHODS: 6 patients with chronic periodontitis were following treatment observed for a period of six years for local sites staying healthy, local sites with periodontal pathology but without signs of progression of attachment loss and sites with verified progression were biopsied . The biopsies were lyzed and analyzed for levels of cytokine mRNAs . RESULTS: Results revealed considerable variation not only between patients, but also between individual sites . Each patient's site has thus to be looked at as an independent entity . CONCLUSIONS: The local action of cytokines, which is heavily dependent on recruitment, interaction and activation of immunocompetent cells can explain the site-specific nature of cytokine expression . Cytokine data from individual sites together with the local clinical status and data from the literature demonstrate the complexity of periodontal disease pathogenesis . To gain insight to specific mechanisms further studies are needed. J Clin Periodontol, 2001 Sep, 28(9), 820 - 7 Subgingival debridement of root surfaces with a micro-brush: macroscopic and ultrastructural assessment; Carey HM et al.; AIM: The aim of this study was to assess the use of a micro-brush to remove plaque deposits from subgingival, periodontally involved root surfaces in vivo . METHODS: 30 periodontally involved teeth requiring extraction for periodontal or prosthetic reasons in 26 adult patients were utilised . For inclusion, teeth had to display at least 30% bone loss radiographically . Following the establishment of local anaesthesia, grooves were cut on the proximal root surface adjacent to the gingival margin at the line angles . For each tooth, 1 proximal root surface was rubbed with the micro-brush for 2 min to the depth of the pocket whilst the other root surface acted as an undebrided control . The teeth were then extracted, rinsed in 0.85% NaCl, stained with 2% erythrosine solution and photographed . The amount of erythrosine staining on each subgingival, periodontally involved root surface was assessed by tracing the areas of stain on a colour photograph and scanning the tracings into a computerised image tracing program . RESULTS: Results were expressed as the % of the periodontally involved root-surface area that exhibited staining . Stained areas were further examined with the scanning electron microscope (SEM) . The undebrided root surfaces each displayed 100% staining . The debrided surfaces (with probing pocket depths of 4-10 mm) displayed mean staining of 16.1% (SD +/-7.1%) of the proximal surface area . SEM assessment showed that undebrided root surfaces were covered with thick deposits of bacteria . On debrided surfaces, stain-free areas were free of plaque whilst areas of faint staining exhibited either no plaque, calculus deposits or scanty, isolated islands of bacteria . Bacteria had been partially removed from the surface of calculus in some areas . CONCLUSIONS: The findings indicate that subgingival debridement with a micro-brush is effective in removing plaque deposits from periodontally involved root surfaces. Int J Syst Evol Microbiol, 2001 Jul, 51(Pt 4), 1267 - 76 Description of Microbacterium foliorum sp . nov . and Microbacterium phyllosphaerae sp . nov., isolated from the phyllosphere of grasses and the surface litter after mulching the sward, and reclassification of Aureobacterium resistens (Funke et al . 1998) as Microbacterium resistens comb . nov.; Behrendt U et al.; The taxonomic position of a group of coryneform bacteria isolated from the phyllosphere of grasses and the surface litter after sward mulching was investigated . On the basis of restriction analyses of 16S rDNA, the isolates were divided into two genotypes . According to the 16S rDNA sequence analysis, representatives of both genotypes were related at a level of 99.2% similarity and clustered within the genus Microbacterium . Chemotaxonomic features (major menaquinones MK-12, MK-11 and MK-10; predominating iso- and anteiso-branched cellular fatty acids; G+C content 64-67 mol%; peptidoglycan-type B2beta with glycolyl residues) corresponded to this genus as well . DNA-DNA hybridization studies showed a reassociation value of less than 70% between representative strains of both subgroups, suggesting that two different species are represented . Although the extensive morphological and physiological analyses did not reveal any differentiating feature for the genotypes, differences in the presence of the cell-wall sugar mannose enabled the subgroups to be distinguished from one another . DNA-DNA hybridization with type strains of closely related Microbacterium spp . indicated that the isolates represent two individual species, which can also be differentiated from previously described species of Microbacterium on the basis of biochemical features . As a result of phenotypic and phylogenetic analyses, the species Microbacterium foliorum sp . nov., type strain P 333/02T (= DSM 12966T = LMG 19580T), and Microbacterium phyllosphaerae sp . nov., type strain P 369/06T (= DSM 13468T = LMG 19581T), are proposed . Furthermore, the reclassification of Aureobacterium resistens (Funke et al . 1998) as Microbacterium resistens (Funke et al . 1998) comb . nov . is proposed. J Mol Biol, 2001 May 25, 309(1), 121 - 38 The RegB/RegA two-component regulatory system controls synthesis of photosynthesis and respiratory electron transfer components in Rhodobacter capsulatus; Swem LR et al.; Recently, we demonstrated that the RegB/RegA two-component regulatory system from Rhodobacter capsulatus functions as a global regulator of metabolic processes that either generate or consume reducing equivalents . For example, the RegB/RegA system controls expression of such energy generating processes as photosynthesis and hydrogen utilization . In addition, RegB/RegA also control nitrogen and carbon fixation pathways that utilize reducing equivalents . Here, we use a combination of DNase I protection and plasmid-based reporter expression studies to demonstrate that RegA directly controls synthesis of cytochrome cbb3 and ubiquinol oxidases that function as terminal electron acceptors in a branched respiratory chain . We also demonstrate that RegA controls expression of cytochromes c2, c(y) and the cytochrome bc1 complex that are involved in both photosynthetic and respiratory electron transfer events . These data provide evidence that the RegB/RegA two-component system has a major role in controlling the synthesis of numerous processes that affect reducing equivalents in Rhodobacter capsulatus. Eur Respir J, 2001 Jun, 17(6), 1322 - 7 A small outbreak of Legionnaires' disease in a cargo ship under repair; Cayla JA et al.; It was reported that two mechanics working on a cargo ship under repair in the port of Barcelona had died after having fever . An investigation was made into the possibility of any additional cases and the presence of Legionella pneumophila in the ship they were repairing and in their hotel . The contaminated water system was treated with sodium hypochlorite . Both patients died after having been repeatedly diagnosed as having influenza . The two cases occurred among those who had been working with the pump of the ship's water system, while no cases were observed among the other workers (p = 0.02) . Various serogroups of L . pneumophila were isolated from the ship's water pump and distribution system . However, organism of serogroup 1, subgroup Pontiac (Knoxville) were identified with identical deoxyribonucleic acid (DNA) patterns in the lung tissue of one patient and in the cooling water circuit valve of the ship's water pump . The first postintervention control water samples showed no further growth of legionella, but serogroups 4 and 8 were identified 8 months later . This legionellosis outbreak, although small, was highly lethal, probably due to the high levels of bacteria to which the patients were exposed and also because of the failure of correct diagnosis . International recommendations on prevention and control of legionellosis, which include ships under repair, are required. J Cell Biol, 2001 Aug 6, 154(3), 549 - 71 A protein interaction map for cell polarity development; Drees BL et al.; Many genes required for cell polarity development in budding yeast have been identified and arranged into a functional hierarchy . Core elements of the hierarchy are widely conserved, underlying cell polarity development in diverse eukaryotes . To enumerate more fully the protein-protein interactions that mediate cell polarity development, and to uncover novel mechanisms that coordinate the numerous events involved, we carried out a large-scale two-hybrid experiment . 68 Gal4 DNA binding domain fusions of yeast proteins associated with the actin cytoskeleton, septins, the secretory apparatus, and Rho-type GTPases were used to screen an array of yeast transformants that express approximately 90% of the predicted Saccharomyces cerevisiae open reading frames as Gal4 activation domain fusions . 191 protein-protein interactions were detected, of which 128 had not been described previously . 44 interactions implicated 20 previously uncharacterized proteins in cell polarity development . Further insights into possible roles of 13 of these proteins were revealed by their multiple two-hybrid interactions and by subcellular localization . Included in the interaction network were associations of Cdc42 and Rho1 pathways with proteins involved in exocytosis, septin organization, actin assembly, microtubule organization, autophagy, cytokinesis, and cell wall synthesis . Other interactions suggested direct connections between Rho1- and Cdc42-regulated pathways; the secretory apparatus and regulators of polarity establishment; actin assembly and the morphogenesis checkpoint; and the exocytic and endocytic machinery . In total, a network of interactions that provide an integrated response of signaling proteins, the cytoskeleton, and organelles to the spatial cues that direct polarity development was revealed. J Bacteriol, 2001 Sep, 183(17), 5209 - 12 Dehalogenation of dichloromethane by dichloromethane dehalogenase/glutathione S-transferase leads to formation of DNA adducts; Kayser MF et al.; Formation of DNA adducts following conversion of dichloromethane by bacterial dichloromethane dehalogenase/glutathione S-transferase was demonstrated . Adducts included dichloromethane carbon and glutathione sulfur atoms . A reaction with DNA occurred preferentially at guanine bases . Increased DNA degradation in a polA mutant of Methylobacterium dichloromethanicum DM4 grown with dichloromethane confirmed the genotoxicity associated with dichloromethane degradation, suggesting an important role of DNA repair in the metabolism of halogenated, DNA-alkylating compounds by bacteria. J Bacteriol, 2001 Sep, 183(17), 5092 - 101 Differential regulation of ftsZ transcription during septation of Streptomyces griseus; Kwak J et al.; Streptomyces has been known to form two types of septa . The data in this research demonstrated that Streptomyces griseus forms another type of septum near the base of sporogenic hyphae (basal septum) . To understand the regulation of the septation machinery in S . griseus, we investigated the expression of the ftsZ gene . S1 nuclease protection assays revealed that four ftsZ transcripts were differentially expressed during morphological differentiation . The vegetative transcript (emanating from P(veg)) is present at a moderate level during vegetative growth, but is switched off within the first 2 h of sporulation . Two sporulation-specific transcripts predominantly accumulated, and the levels increased by approximately fivefold together shortly before sporulation septa begin to form . Consistently, the sporulation-specific transcripts were expressed much earlier and more abundantly in a group of nonsporulating mutants that form their sporulation septa prematurely . Promoter-probe studies with two different reporter systems confirmed the activities of the putative promoters identified from the 5' end point of the transcripts . The levels and expression timing of promoter activities were consistent with the results of nuclease protection assays . The aseptate phenotype of the P(spo) mutant indicated that the increased transcription from P(spo) is required for sporulation septation, but not for vegetative or basal septum formation. J Bacteriol, 2001 Sep, 183(17), 5001 - 7 Proteolysis of the Caulobacter McpA chemoreceptor is cell cycle regulated by a ClpX-dependent pathway; Tsai JW et al.; Proteolysis is involved in cell differentiation and the progression through the cell cycle in Caulobacter crescentus . We have constitutively expressed the transmembrane chemoreceptor McpA from a multicopy plasmid to demonstrate that McpA degradation is modulated during the cell cycle . The level of McpA protein starts to decrease only when the swarmer cells differentiate into stalked cells . The reduction in McpA protein levels is maintained until the stalked cells develop into predivisional cells, at which point the level returns to that observed in swarmer cells . The cell-cycle-regulated degradation of McpA does not require the last 12 C-terminal amino acids, but it does require three amino acids (AAL) located 15 residues away from the C terminus . The ClpXP protease is essential in C . crescentus for viability, and thus, we tested McpA degradation in xylose conditional mutants . The effect on McpA degradation occurred within two generations from the start of ClpX depletion . The conditional mutants' growth rate was only slightly affected, suggesting that ClpX is directly involved in McpA proteolysis. J Control Release, 2001 Jul 6, 74(1-3), 357 - 62 Phage derived peptides for targeting of doxorubicin conjugates to solid tumours; Schatzlein AG et al.; Barriers are frequently hampering targeting of drugs and toxins to solid tumours and their microenvironment . Nano-conjugates are low molecular weight conjugates of a small drug or toxin and a targeting ligand coupled through a cleavable linker group . They offer potential advantages for tumour specific delivery in diffusion-limited situations . We have exploited fd phage-derived peptides for the targeting of low molecular weight drug conjugates to solid tumours . As a model we have chosen doxorubicin conjugates targeted to the transferrin receptor (TfR) . A library of phage expressing a cyclic nona-peptide was panned against TfR . The apparent affinity of phages determined by surface plasmon resonance (SPR) increased with each cycle of the panning procedure . After five rounds approximately 80% of phages expressed the same peptide, which mediated a 30-50-fold increased receptor specific cellular uptake of the phages . The corresponding peptide was synthesised using solid phase peptide chemistry on a sulfonamide based safety catch resin . Crude mixtures of the peptide, as well as transferrin itself, were able to inhibit the phage uptake significantly . The doxorubicin conjugate of the peptide containing a cleavable linker was prepared and endosomal uptake confirmed by fluorescence microscopy. Microbes Infect, 2001 Jul, 3(9), 729 - 38 Classification of Brucella spp . isolated from marine mammals by DNA polymorphism at the omp2 locus; Cloeckaert A et al.; A number of recent reports have described the isolation and characterization of Brucella strains from a wide variety of marine mammals such as seals, porpoises, dolphins and a minke whale . These strains were identified as brucellae by conventional typing tests . However, their overall characteristics were not assimilable to those of any of the six currently recognized Brucella species and it was suggested that they comprise a new nomen species to be called Brucella maris . In the present study we analysed DNA polymorphism at the omp2 locus of 33 marine mammal Brucella strains isolated from seals, dolphins, porpoises and an otter . The omp2 locus contains two gene copies (named omp2a and omp2b) coding for porin proteins and has been found particularly useful for molecular typing and identification of Brucella at the species, biovar, or strain level . PCR-restriction fragment length polymorphism (RFLP) and DNA sequencing showed that strains isolated from dolphins and porpoises carry two omp2b gene copies instead of one omp2a and one omp2b gene copy or two similar omp2a gene copies reported in the currently recognized species . This observation was also recently made for a minke whale Brucella isolate . The otter and all seal isolates except one were shown to carry one omp2a and one omp2b gene copy as encountered in isolates from terrestrial mammals . By PCR-RFLP of the omp2b gene, a specific marker was detected grouping the marine mammal Brucella isolates . Although marine mammal Brucella isolates may represent a separate group from terrestrial mammal isolates based on omp2b sequence constructed phylogenetic trees, the divergence found between their omp2b and also between their omp2a nucleotide sequences indicates that they form a more heterogeneous group than isolates from terrestrial mammals . Therefore, grouping the marine mammal Brucella isolates into one species Brucella maris seems inappropriate unless the currently recognized Brucella species are grouped . With respect to the current classification of brucellae according to the preferential host, brucellae isolated from such diverse marine mammal species as seals and dolphins could actually comprise more than one species, and at least two new species, B . pinnipediae and B . cetaceae, could be compatible with the classical criteria of host preferentialism and DNA polymorphism at their omp2 locus. Mol Microbiol, 2001 Jul, 41(2), 423 - 37 The Mycobacterium tuberculosis ECF sigma factor sigmaE: role in global gene expression and survival in macrophages; Manganelli R et al.; In previously published work, we identified three Mycobacterium tuberculosis sigma (sigma) factor genes responding to heat shock (sigB, sigE and sigH) . Two of them (sigB and sigE) also responded to SDS exposure . As these responses to stress suggested that the sigma factors encoded by these genes could be involved in pathogenicity, we are studying their role in physiology and virulence . In this work, we characterize a sigE mutant of M . tuberculosis H37Rv . The sigE mutant strain was more sensitive than the wild-type strain to heat shock, SDS and various oxidative stresses . It was also defective in the ability to grow inside both human and murine unactivated macrophages and was more sensitive than the wild-type strain to the killing activity of activated murine macrophages . Using microarray technology and quantitative reverse transcription-polymerase chain reaction (RT-PCR), we started to define the sigmaE regulon of M . tuberculosis and its involvement in the global regulation of the stress induced by SDS . We showed the requirement for a functional sigE gene for full expression of sigB and for its induction after SDS exposure but not after heat shock . We also identified several genes that are no longer induced when sigmaE is absent . These genes encode proteins belonging to different classes including transcriptional regulators, enzymes involved in fatty acid degradation and classical heat shock proteins. Heredity, 2001 Mar, 86(Pt 3), 325 - 32 Wolbachia endosymbiont responsible for cytoplasmic incompatibility in a terrestrial crustacean: effects in natural and foreign hosts; Moret Y et al.; Wolbachia bacteria are vertically transmitted endosymbionts that disturb the reproduction of many arthropods thereby enhancing their spread in host populations . Wolbachia are often responsible for changes of sex ratios in terrestrial isopods, a result of the feminization of genotypic males . Here we found that the Wolbachia hosted by Cylisticus convexus (wCc) caused unidirectional cytoplasmic incompatibility (CI), an effect commonly found in insects . To understand the diversity of Wolbachia-induced effects in isopods, wCc were experimentally transferred in a novel isopod host, Armadillidium vulgare . wCc conserved the ability to induce CI . However, Wolbachia were not transmitted to the eggs, so the capacity to restore the compatibility in crosses involving two transinfected individuals was lost . The feminizing Wolbachia hosted by A . vulgare was unable to rescue CI induced by wCc . These results showed that Wolbachia in isopods did not evolved broadly to induce feminization, and that CI and the feminizing effect are probably due to different mechanisms . In addition, wCc reduces the mating capacity of infected C . convexus males, suggesting that the bacteria might alter reproductive behaviour . The maintenance of wCc in host populations is discussed. Eur Respir J, 2001 May, 17(5), 1049 - 51 Interleukin-12 as successful adjuvant in tuberculosis treatment; Greinert U et al.; Interleukin-12 (IL-12) proved to be an effective and successful adjuvant to a standard antituberculotic medication in a patient suffering from progressive clinical tuberculosis (TB) . IL-12 is a potent enhancer of interferon-gamma production which is necessary for killing intracellular bacteria like mycobacteria . This patient's TB was progressive, although sensitivity to first-line antituberculotics was proven and medication was given as directly observed therapy over more than 8 months . The 3-month adjuvant therapy with IL-12 significantly and convincingly improved results . It is believed that this case, the first in the literature to describe adjuvant interleukin-12 therapy in tuberculosis, strongly encourages the study of adjuvant interleukin-12 therapy on a more systematic basis. Front Biosci, 2001 Aug 01, 6, D927 - 35 Features of the two gene pairs RD-SKI2W and DOM3Z-RP1 located between complement component genes factor B and C4 at the MHC class III region; Yang Z et al.; Located at the 30 kb genomic region between complement factor B and component C4 are four ubiquitously expressed genes RD, SKI2W, DOM3Z and RP1 . Besides RP1, the protein products of the other three genes each has highly conserved homologues or related proteins in lower eukaryotes, contains leucine zipper motifs for protein interaction, and plays important roles related to RNA metabolism . RD is a subunit of the negative transcription elongation factor, critical for the regulation of gene expression . It has an RNA recognition motif and 24 copies of Arg-Asp (RD) repeats . Ski2w is a nucleolar and cytoplasmic protein that has a putative RNA helicase domain . Fusion proteins of human Ski2w expressed in insect cells and bacteria have ATPase activity . The cytoplasmic protein of human Ski2w is associated with the polysomes and probably the 40S subunit of ribosomes . Ski2w is probably involved in the regulation of translation and RNA turnover . Dom3z is a nuclear protein whose yeast homologue forms a complex with an exoribonuclease . RP1 (or STK19) is a Ser/Thr nuclear protein kinase . No homologues of RP1 in lower eukaryotes have been discovered . Six polymorphic residues are present in human Ski2w and two in Dom3z . The potential roles of Ski2w and Dom3z on the clearance of degraded nuclear and cytoplasmic RNA raised their possibilities as susceptibility genes of systemic lupus erythematosus that is a disease with flawed processes in the removal of apoptotic materials. J Immunoassay Immunochem, 2001, 22(2), 99 - 112 A specific and ultrasensitive chemiluminescent sandwich ELISA test for the detection and quantitation of pneumolysin; Cima-Cabal MD et al.; A chemiluminescent sandwich ELISA test has been developed for the detection and quantitation of pneumolysin . The test is based on a mouse monoclonal as the capture antibody and on rabbit polyclonal IgGs as detection antibodies, in combination with an anti-rabbit IgG alkaline phosphatase conjugate . The estimated detection limit of the purified recombinant toxin in phosphate-buffered saline with 0.05% Triton X-100 is around 5 pg ml(-1), with averaged intra- and inter-assay variation coefficients of 7% and 13.5%, respectively . The assay has been applied to the quantitation of pneumolysin in pneumococcal isolates, providing, for the first time, a direct measurement of the amount of the toxin produced by different strains, a variation has been found in their pneumolysin content . The test is highly specific as no other purified toxins or human pneumonia- or meningitis-associated bacteria yielded false-positive results . This specific and highly sensitive method could help in the diagnosis of human infections. Clin Infect Dis, 2001 Sep 1, 33(5), 629 - 40 Epub 2001 Aug 06. Infectious complications among 620 consecutive heart transplant patients at Stanford University Medical Center; Montoya JG et al.; A total of 1073 infectious episodes (IEs) that occurred in 620 consecutive heart transplantation patients at Stanford Medical Center between 16 December 1980 and 30 June 1996 were reviewed . Infectious complications were a major cause of morbidity and mortality, second only to rejection as the cause of early deaths and the most common cause of late deaths . Of the IEs, 468 (43.6%) were caused by bacteria, 447 (41.7%) by viruses, 109 (10.2%) by fungi, 43 (4.0%) by Pneumocystis carinii, and 6 (0.6%) by protozoa . The largest number of IEs occurred in the lungs (301 {28.1%}) . A significant reduction in the incidence of IEs and a delay in presentation after transplantation were observed; these were most likely related to the introduction of new chemoprophylactic regimens during the study period and prevention of significant disease caused by cytomegalovirus. Hum Pathol, 2001 Jul, 32(7), 750 - 2 Leptospirosis mimicking acute cholecystitis among athletes participating in a triathlon; Guarner J et al.; Leptospirosis, a disease acquired by exposure to contaminated water, is characterized by fever accompanied by various symptoms, including abdominal pain . An acute febrile illness occurred in athletes who participated in an Illinois triathlon in which the swimming event took place in a freshwater lake . Of 876 athletes, 120 sought medical care and 22 were hospitalized . Two of the athletes had their gallbladders removed because of abdominal pain and clinical suspicion of acute cholecystitis . We applied an immunohistochemical test for leptospirosis to these gallbladders and demonstrated bacterial antigens staining (granular and filamentous patterns) around blood vessels of the serosa and muscle layer . Rare intact bacteria were seen in 1 case . These results show that leptospirosis can mimic the clinical symptoms of acute cholecystitis . If a cholecystectomy is performed in febrile patients with suspicious environmental or animal exposure, pathologic studies for leptospirosis on formalin-fixed, paraffin-embedded tissues may be of great value. Science, 2001 Aug 3, 293(5531), 839 - 43 Biogenic methane, hydrogen escape, and the irreversible oxidation of early Earth; Catling DC et al.; The low O2 content of the Archean atmosphere implies that methane should have been present at levels approximately 10(2) to 10(3) parts per million volume (ppmv) (compared with 1.7 ppmv today) given a plausible biogenic source . CH4 is favored as the greenhouse gas that countered the lower luminosity of the early Sun . But abundant CH4 implies that hydrogen escapes to space (upward arrow space) orders of magnitude faster than today . Such reductant loss oxidizes the Earth . Photosynthesis splits water into O2 and H, and methanogenesis transfers the H into CH4 . Hydrogen escape after CH4 photolysis, therefore, causes a net gain of oxygen {CO2 + 2H2O --> CH4 + 2O2 --> CO2 + O2 + 4H(upward arrow space)} . Expected irreversible oxidation (approximately 10(12) to 10(13) moles oxygen per year) may help explain how Earth's surface environment became irreversibly oxidized. Mol Cell Biol, 2001 Sep, 21(17), 6044 - 55 Intact lysosome transport and phagosome function despite kinectin deficiency; Plitz T et al.; The mechanism of cargo coupling to kinesin motor proteins is a fundamental issue in organelle transport along microtubules . Kinectin has been postulated to function as a membrane anchor protein that attaches various organelles to the prototype motor protein kinesin . To verify the biological relevance of kinectin in vivo, the murine kinectin gene was disrupted by homologous recombination . Unexpectedly, kinectin-deficient mice were viable and fertile, and no gross abnormalities were observed up to 1 year of age . The assembly of the endoplasmic reticulum was essentially unaffected in kinectin-deficient cells . Mitochondria appeared to be correctly distributed throughout the cytoplasm along the microtubules . Furthermore, the stationary distribution and the bidirectional movement of lysosomes did not depend on kinectin . Kinectin-deficient phagocytes internalized and cleared bacteria, indicating that phagosome trafficking and maturation are functional without kinectin . Thus, these data unequivocally indicate that kinectin is not essential for trafficking of lysosomes, phagosomes, and mitochondria in vivo. J Photochem Photobiol B, 2001 Aug 15, 61(1-2), 35 - 45 Photodegradation of natural organic matter exposed to fluctuating levels of solar radiation; Zagarese HE et al.; Irradiation of natural water samples with natural or artificial UVR typically results in a progressive loss of color and decreased absorbance; a process often referred to as photobleaching . In a typical photobleaching experiment, samples are exposed to a relatively constant level of artificial or natural UVR . However, under most natural situations, the vertical mixing of the water within the upper mixed layer results in strong and periodic fluctuations in UV irradiance . In this paper, we present the results of an experiment in which natural lake water was exposed to solar radiation in quartz tubes that were incubated either at fixed depths or rotating within the water column . We found differences between rotating and fixed samples in (i) photobleaching, (ii) nutrient release, and (iii) subsequent use by algae and bacteria . The evidence presented in this study demonstrated that photochemical processes might be affected by vertical water motion . The reasons for such differences remain largely unknown . Although we offer a potential explanation for such differences, our proposed mechanism is based on a post-hoc analysis of the data and should be taken solely as a working hypothesis for future research. Biotechnol Prog, 2001 Jul-Aug, 17(4), 752 - 9 Hyperaccumulation of nickel by hairy roots of alyssum species: comparison with whole regenerated plants; Nedelkoska TV et al.; Hairy roots were used to investigate nickel uptake by the hyperaccumulator species, Alyssum bertolonii, A . tenium, and A . troodii . The Ni biosorption capacity of A . tenium hairy roots was lower than for other types of biomass such as bacteria and algae; in short-term (9-h) equilibrium studies, the highest Ni content measured in the roots was 17 500 microg g(-1) dry weight at a liquid concentration of about 4000 ppm . Using long-term hairy root cultures, it was demonstrated that Ni tolerance and hyperaccumulation do not necessarily depend on the presence of shoots or root-shoot translocation . A . bertolonii hairy roots remained healthy in appearance and continued to grow in the presence of 20-100 ppm Ni, accumulating up to 7200 microg g(-1) dry weight Ni . In contrast, hairy roots of Nicotiana tabacum turned dark brown at 20 ppm Ni and growth was negligible . The ability to grow at high external Ni concentrations allowed hyperaccumulator hairy roots to remove much greater amounts of heavy metals from the culture liquid than nonhyperaccumulator hairy roots, even though biomass Ni concentrations were similar . Although hairy roots proved to be a useful tool for investigating Ni hyperaccumulation, there were significant differences in the Ni uptake capacity of hairy roots and whole plants . Regenerated plants of A . tenium were much more tolerant of Ni and capable of accumulating higher Ni concentrations than hairy roots of this species. Southeast Asian J Trop Med Public Health, 2001 Mar, 32(1), 171 - 6 Cutaneous manifestations in HIV positive patients; Supanaranond W et al.; Cutaneous manifestations are common clinical findings among HIV positive patients . The causes may be bacteria, viruses, fungi and other non-infectious agents . This study was conducted at the Pramongkutklao Hospital skin clinic to determine the frequency distribution of cutaneous manifestations in HIV positive patients . A total of 147 patients with HIV seropositivity were recruited and divided into a retrospective group and a prospective study group . For the retrospective study, hospital records of 129 patients who attended from January 1995 to November 1998 were recruited . The prospective study was carried out from November 1998 to January 1999 and 18 patients were recruited . Cutaneous finding among patients in the two studies were evaluated . There were ten common cutaneous manifestations observed in the retrospective and prospective study including pruritic papular eruptions (PPE) (51.2%, 50%), oral candidiasis (16.7%, 21.7%), herpes zoster (10.9%, 5.6%), oral hairy leukoplakia (10%, 5.6%), unclassified eczema (9%, 11.1%), urticaria (5.6%, 3.1%), seborrheic dermatitis (4.7%, 16.7%), folliculitis (4.7%, 5.6%), prurigo simplex (4.7%, 5.6%), and Steven-Johnson syndrome (3.9%, 0%) . However, the distribution of cutaneous manifestations in the two studies were not significantly different . These findings may be useful as baseline data for common cutaneous manifestations in HIV positive patients. Integr Physiol Behav Sci, 2001 Jan-Mar, 36(1), 75 - 83 Is there a role for psychology in ulcer disease? Murison R. The discovery of the importance of bacterial factors in the etiology of ulcer disease has led to a neglect of psychological factors . However, both earlier theoretical and empirical approaches implicating these factors are supported by more recent studies, both epidemiological and experimental . While not ignoring the unquestioned role of Helicobacter, it is important for future research to recognize the multi-factorial nature of ulcer disease by which several factors, including stress, bacteria and non-steroid antiinflammatory drugs, may interact to drive a pre-pathology (erosions or ulcerations) to a pathological state (ulcer) . Calls for general eradication programs should be cautioned in the light of possible unwanted side effects. J Virol, 2001 Sep, 75(17), 8187 - 94 Expression of immunoregulatory cytokines by recombinant coxsackievirus B3 variants confers protection against virus-caused myocarditis; Henke A et al.; Clinical and laboratory investigations have demonstrated the involvement of viruses and bacteria as potential causative agents in cardiovascular disease and have specifically found coxsackievirus B3 (CVB3) to be a leading cause . Experimental data indicate that cytokines are involved in controlling CVB3 replication . Therefore, recombinant CVB3 (CVB3rec) variants expressing the T-helper-1 (T(H)1)-specific gamma interferon (IFN-gamma) or the T(H)2-specific interleukin-10 (IL-10) as well as the control virus CVB3(muIL-10), which produce only biologically inactive IL-10, were established . Coding regions of murine cytokines were cloned into the 5' end of the CVB3 wild type (CVB3wt) open reading frame and were supplied with an artificial viral 3Cpro-specific Q-G cleavage site . Correct processing releases active cytokines, and the concentration of IFN-gamma and IL-10 was analyzed by enzyme-linked immunosorbent assay and bioassays . In mice, CVB3wt was detectable in pancreas and heart tissue, causing massive destruction of the exocrine pancreas as well as myocardial inflammation and heart cell lysis . Most of the CVB3wt-infected mice revealed virus-associated symptoms, and some died within 28 days postinfection . In contrast, CVB3rec variants were present only in the pancreas of infected mice, causing local inflammation with subsequent healing . Four weeks after the first infection, surviving mice were challenged with the lethal CVB3H3 variant, causing casualties in the CVB3wt- and CVB3(muIL-10)-infected groups, whereas almost none of the CVB3(IFN-gamma)- and CVB3(IL-10)-infected mice died and no pathological disorders were detectable . This study demonstrates that expression of immunoregulatory cytokines during CVB3 replication simultaneously protects mice against a lethal disease and prevents virus-caused tissue destruction. Vaccine, 2001 Aug 14, 19(31), 4465 - 72 Role of antibody to lipopolysaccharide in protection against low- and high-virulence strains of Francisella tularensis; Fulop M et al.; Mice immunised with lipopolysaccharide (LPS) from Francisella tularensis were protected against challenge with the live vaccine strain (LVS) . However, when similarly immunised mice were challenged using the fully virulent F . tularensis strain Schu4, only an increase in the time to death was observed . Passive transfer of serum from LPS-immunised mice to naive mice afforded protection against F . tularensis LVS . LPS-immunised mice depleted of either CD4+ or CD8+ T-cells survived a F . tularensis LVS challenge although the rate of clearance of bacteria from the spleen was significantly reduced in the CD8+ depleted group . LPS-immunised mice boosted with F . tularensis LVS were re-challenged with F . tularensis Schu4 . This cohort was significantly protected (LD(50) increased from <1 to >1000 CFU) . However, passive transfer of serum did not confer protection and mice depleted of CD4+ or CD8+ T-cells did not survive. Environ Technol, 2001 Jun, 22(6), 661 - 72 Biological sulfide oxidation in a fluidized bed reactor; Annachhatre AP et al.; Feasibility of a laboratory scale fluidized bed process for biological sulfide oxidation to elemental sulfur and the formation of well-settleable sulfur sludge is demonstrated . Sulfide oxidation strongly depends upon oxygen concentration, sulfide loading rate and upflow velocity . At reactor dissolved oxygen concentrations (DOr) higher than 0.1 mg l(-1), sulfate was the main product of sulfide oxidation Upon increasing the sulfide loading rate, the sulfate production rate decreased as sulfide oxidation to sulfur showed marked increase . Low formation of sulfate could mean that sulfide was inhibitory to sulfate producing bacteria or that conversion of sulfide to sulfur was more favorable than sulfate production . Sulfide conversions higher than 90% were obtained at sulfide loading rates of 0.13-1.6 kgS mr(-3) d(-1) . At DOr less than 0.1 mg l(-1), sulfur was the major end product of the sulfide oxidation . Upflow velocity in the range of 16-26 m h(-1) and sulfide loading rate of 0.9-1.6 kgS mr(-3) d(-1) were necessary for generation of biogranules containing 65-76% of elemental sulfur . The elemental sulfur production of 76% was obtained at upflow velocity of 17 m h(-1) with sulfide loading rate up to 1.6 kgS mr(3)d(-1) . Morphological examination of the biogranules showed elemental sulfur deposition in the sludge granule and outside the bacterial cells. Aust Endod J, 2001 Apr, 27(1), 12 - 21 Biocompatibility of root canal filling materials; Geurtsen W; Results of in vitro and in vivo studies clearly indicate that some endodontic sealers may cause local and systemic adverse effects . Though occasionally contradictory data has been reported from various authors, it may be concluded that zinc-oxide-eugenol sealers possess a marked cytotoxic and tissue-irritating potency . Most Ca(OH)2-based materials, however, were biocompatible . Genotoxic effects have been observed with sealers releasing paraformaldehyde or containing mutagenic substances, such as bisphenol-A-diglycidyl-ether or its derivatives . It cannot be excluded that these materials may pose a systemic risk because formaldehyde is rapidly distributed systemically following its application into the pulp cavity . Furthermore an increasing number of cases with an aspergillosis of the maxillary sinus have been observed which were mainly caused by zinc-releasing endodontic sealers . Overall, it is recommended that for endodontic practice, sealers that have been found to be biocompatible in a "mixed bag" of various in vitro and in vivo tests, be selected . From this point of view, ZnOE-sealers should no longer be used for root canal fillings . This recommendation applies also to sealers containing paraformaldehyde or generating this substance during their setting reaction . More experimental and clinical studies are necessary to elucidate whether new materials, such as mineral trioxide aggregate (MTA) or calcium phosphate cement, will be biocompatible alternatives in the future. Naturwissenschaften, 2001 Apr, 88(4), 137 - 46 Climate change and temperature-dependent biogeography: oxygen limitation of thermal tolerance in animals; Portner HO; Recent years have shown a rise in mean global temperatures and a shift in the geographical distribution of ectothermic animals . For a cause and effect analysis the present paper discusses those physiological processes limiting thermal tolerance . The lower heat tolerance in metazoa compared with unicellular eukaryotes and bacteria suggests that a complex systemic rather than molecular process is limiting in metazoa . Whole-animal aerobic scope appears as the first process limited at low and high temperatures, linked to the progressively insufficient capacity of circulation and ventilation . Oxygen levels in body fluids may decrease, reflecting excessive oxygen demand at high temperatures or insufficient aerobic capacity of mitochondria at low temperatures . Aerobic scope falls at temperatures beyond the thermal optimum and vanishes at low or high critical temperatures when transition to an anaerobic mitochondrial metabolism occurs . The adjustment of mitochondrial densities on top of parallel molecular or membrane adjustments appears crucial for maintaining aerobic scope and for shifting thermal tolerance . In conclusion, the capacity of oxygen delivery matches full aerobic scope only within the thermal optimum . At temperatures outside this range, only time-limited survival is supported by residual aerobic scope, then anaerobic metabolism and finally molecular protection by heat shock proteins and antioxidative defence . In a cause and effect hierarchy, the progressive increase in oxygen limitation at extreme temperatures may even enhance oxidative and denaturation stress . As a corollary, capacity limitations at a complex level of organisation, the oxygen delivery system, define thermal tolerance limits before molecular functions become disturbed. Leukemia, 2001 Aug, 15(8), 1248 - 55 The multi-organ origin of interleukin-5 in the mouse; Ryan PJ et al.; Murine Ba/F3 cells were transfected with cDNA for the alpha-chain of the murine interleukin-5 (IL-5) receptor and cloned lines of these cells were able to proliferate in response to as little as 2.5 pg/ml of IL-5 . The bioassay was demonstrated to be specific for IL-5 and was able to measure IL-5 produced in culture by organs from adult C57BL/6 and BALB/c mice . The highest levels of IL-5 were produced by lung tissue but thymus and bladder consistently produced IL-5 and more variable production was observed by the heart, spleen, muscle, bone shaft, uterus and testes . Bone marrow cells produced no detectable IL-5 . Observed levels of production of IL-5 were similar when using organs from mice lacking high-affinity receptors for IL-5 and from nu/nu, RAG-1-/- and NOD/SCID mice lacking T lymphocytes . In inflammatory peritoneal exudates induced by the injection of casein plus bacteria, levels of induced IL-5 were higher if the mice lacked high-affinity receptors for IL-5 . The data indicate that T lymphocytes are not the dominant cellular source of IL-5 in organ-conditioned media and that local IL-5 production can occur with a wide range of normal murine organs. J Pediatr Surg, 2001 Aug, 36(8), 1122 - 9 Intestinal cytokine gene expression in infants with acute necrotizing enterocolitis: interleukin-11 mRNA expression inversely correlates with extent of disease; Nadler EP et al.; BACKGROUND/PURPOSE: The authors have shown previously that surgical specimens from infants with acute necrotizing enterocolitis (NEC) show upregulation of inducible nitric oxide (NO) synthase (iNOS) and interferon-gamma mRNA . However, the contribution of other inflammatory cytokines such as interleukin-8 (IL-8), IL-11, and IL-12 has not been defined . Likewise, the role of GTP-cyclohydrolase, the rate-limiting enzyme in tetrahydrobiopterin synthesis, and thus NO production by iNOS is unclear . In this study, the authors sought to further define the pattern of cytokine expression seen in infants with acute NEC . METHODS: The authors measured intestinal cytokine mRNA expression by semiquantitative reverse transcriptase polymerase chain reaction in 21 infants with histologically confirmed NEC, 18 with other inflammatory conditions, and in 9 patients without intestinal inflammation . Guanosine triphosphate-cyclohydrolase (GTP-CH) activity was measured by specific enzyme assay . Univariate exact logistic regression analysis was performed to identify predictors of outcome . RESULTS: IL-8 and IL-11 mRNA were upregulated in patients with acute NEC compared with those with other inflammatory conditions or those without disease; these levels returned to baseline at the time of stoma closure . Increased IL-11 mRNA decreased the likelihood of pan-necrosis (odds ratio, 0.93; P =.002) . Increased IL-12 levels (but not IL-8) seemed to protect against pan-necrosis (odds ratio, 0.70; P =.06) . CONCLUSIONS: Local upregulation of IL-11 may represent an adaptive response designed to limit the extent of intestinal damage in NEC . Decreased IL-12 levels may contribute to the pathogenesis of NEC by allowing bacteria to escape host defenses . Arch Microbiol, 2001 Jul, 176(1-2), 62 - 8 Characterisation of the mob locus of Rhodobacter sphaeroides WS8: mobA is the only gene required for molybdopterin guanine dinucleotide synthesis; Buchanan G et al.; The mob genes of several bacteria have been implicated in the conversion of molybdopterin to molybdopterin guanine dinucleotide . The mob locus of Rhodobacter sphaeroides WS8 comprises three genes, mobABC . Chromosomal in-frame deletions in each of the mob genes have been constructed . The mobA mutant strain has inactive DMSO reductase and periplasmic nitrate reductase activities (both molybdopterin guanine dinucleotide-requiring enzymes), but the activity of xanthine dehydrogenase, a molybdopterin enzyme, is unaffected . The inability of a mobA mutant to synthesise molybdopterin guanine dinucleotide is confirmed by analysis of cell extracts of the mobA strain for molybdenum cofactor forms following iodine oxidation . Mutations in mobB and mobC are not impaired for molybdoenzyme activities and accumulate wild-type levels of molybdopterin and molybdopterin guanine dinucleotide, indicating they are not compromised in molybdenum cofactor synthesis . In the mobA mutant strain, the inactive DMSO reductase is found in the periplasm, suggesting that molybdenum cofactor insertion is not necessarily a pre-requisite for export. Arch Microbiol, 2001 Jul, 176(1-2), 9 - 18 Pattern of cyanophycin accumulation in nitrogen-fixing and non-nitrogen-fixing cyanobacteria; Li H et al.; The temporal and spatial accumulation of cyanophycin was studied in two unicellular strains of cyanobacteria, the diazotrophic Cyanothece sp . strain ATCC 51142 and the non-diazotrophic Synechocystis sp . strain PCC 6803 . Biochemistry and electron microscopy were used to monitor the dynamics of cyanophycin accumulation under nitrogen-sufficient and nitrogen-deficient conditions . In Cyanothece sp . ATCC 51142 grown under 12 h light/12 h dark nitrogen-fixing conditions, cyanophycin was temporally regulated relative to nitrogenase activity and accumulated in granules after nitrogenase activity commenced . Cyanophycin granules reached a maximum after the peak of nitrogenase activity and eventually were utilized completely . Knock-out mutants were constructed in Synechocystis sp . PCC 6803 cphA and cphB genes to analyze the function of these genes and cyanophycin accumulation under nitrogen-deficient growth conditions . The mutants grew under such conditions, but needed to degrade phycobilisomes as a nitrogen reserve . Granules could be seen in some wild-type cells after treatment with chloramphenicol, but were never found in Delta cphA and Delta cphB mutants . These results led to the conclusion that cyanophycin is temporally and spatially regulated in nitrogen-fixing strains such as Cyanothece sp . ATCC 51142 and represents a key nitrogen reserve in these organisms . However, cyanophycin appeared to play a less important role in the non-diazotrophic unicellular strains and phycobilisomes appeared to be the main nitrogen reserve. Biochemistry, 2001 Aug 7, 40(31), 9238 - 46 Structural changes of pharaonis phoborhodopsin upon photoisomerization of the retinal chromophore: infrared spectral comparison with bacteriorhodopsin; Kandori H et al.; Archaeal rhodopsins possess a retinal molecule as their chromophores, and their light energy and light signal conversions are triggered by all-trans to 13-cis isomerization of the retinal chromophore . Relaxation through structural changes of the protein then leads to functional processes, proton pump in bacteriorhodopsin and transducer activation in sensory rhodopsins . In the present paper, low-temperature Fourier transform infrared spectroscopy is applied to phoborhodopsin from Natronobacterium pharaonis (ppR), a photoreceptor for the negative phototaxis of the bacteria, and infrared spectral changes before and after photoisomerization are compared with those of bacteriorhodopsin (BR) at 77 K . Spectral comparison of the C--C stretching vibrations of the retinal chromophore shows that chromophore conformation of the polyene chain is similar between ppR and BR . This fact implies that the unique chromophore-protein interaction in ppR, such as the blue-shifted absorption spectrum with vibrational fine structure, originates from both ends, the beta-ionone ring and the Schiff base regions . In fact, less planer ring structure and stronger hydrogen bond of the Schiff base were suggested for ppR . Similar frequency changes upon photoisomerization are observed for the C==N stretch of the retinal Schiff base and the stretch of the neighboring threonine side chain (Thr79 in ppR and Thr89 in BR), suggesting that photoisomerization in ppR is driven by the motion of the Schiff base like BR . Nevertheless, the structure of the K state after photoisomerization is different between ppR and BR . In BR, chromophore distortion is localized in the Schiff base region, as shown in its hydrogen out-of-plane vibrations . In contrast, more extended structural changes take place in ppR in view of chromophore distortion and protein structural changes . Such structure of the K intermediate of ppR is probably correlated with its high thermal stability . In fact, almost identical infrared spectra are obtained between 77 and 170 K in ppR . Unique chromophore-protein interaction and photoisomerization processes in ppR are discussed on the basis of the present infrared spectral comparison with BR. J Mol Biol, 2001 Aug 10, 311(2), 297 - 310 Structure and mechanism of the RuvB Holliday junction branch migration motor; Putnam CD et al.; The RuvB hexamer is the chemomechanical motor of the RuvAB complex that migrates Holliday junction branch-points in DNA recombination and the rescue of stalled DNA replication forks . The 1.6 A crystal structure of Thermotoga maritima RuvB together with five mutant structures reveal that RuvB is an ATPase-associated with diverse cellular activities (AAA+-class ATPase) with a winged-helix DNA-binding domain . The RuvB-ADP complex structure and mutagenesis suggest how AAA+-class ATPases couple nucleotide binding and hydrolysis to interdomain conformational changes and asymmetry within the RuvB hexamer implied by the crystallographic packing and small-angle X-ray scattering in solution . ATP-driven domain motion is positioned to move double-stranded DNA through the hexamer and drive conformational changes between subunits by altering the complementary hydrophilic protein- protein interfaces . Structural and biochemical analysis of five motifs in the protein suggest that ATP binding is a strained conformation recognized both by sensors and the Walker motifs and that intersubunit activation occurs by an arginine finger motif reminiscent of the GTPase-activating proteins . Taken together, these results provide insights into how RuvB functions as a motor for branch migration of Holliday junctions . J Investig Med, 2001 Jul, 49(4), 362 - 9 Monocyte chemoattractant protein-1 and interleukin-8 are increased in bronchopulmonary dysplasia: relation to isolation of Ureaplasma urealyticum; Baier RJ et al.; BACKGROUND: An exaggerated inflammatory response occurs in infants who subsequently develop bronchopulmonary dysplasia (BPD) . Ureaplasma urealyticum (Uu) is frequently isolated from cultures of tracheal secretions obtained from very low birth weight infants and is associated with an increased risk of BPD . METHODS: We examined the relationships between isolation of genital mycoplasmas, tracheal aspirate (TA) interleukin-8 (IL-8), and monocyte chemoattractant protein-1 (MCP-1) concentrations and the development of BPD . Serial TAs were obtained prospectively from 35 very low birth weight infants, and IL-8 and MCP-1 concentrations were determined by enzyme-linked immunoadsorbent assay . Tracheal cultures for bacteria and genital mycoplasmas were performed on aspirates obtained during the first 2 days of life . RESULTS: Infants who developed BPD (n=18) were less mature (25.2+/-0.2 vs 27.8+/-0.5 weeks; P<0.001), of lower birth weight (746+/-28 vs 1052+/-41 g; P<0.001), and more likely to have a positive tracheal culture for Uu (39% vs 6%; P=0.026) than those who did not develop BPD (n=17) . Tracheal concentrations of IL-8 and MCP-1 were significantly increased in infants who developed BPD (IL-8: P=0.0001; MCP-1: P<0.001, analysis of variance) and correlated with duration of mechanical ventilation and oxygen treatment . Uu-positive infants had an increased incidence of BPD (88% in infants with Uu vs 42% in infants without Uu; P=0.020) and had TA concentrations of IL-8 and MCP-1 that were significantly increased compared with those of Uu-negative infants . CONCLUSIONS: Increased TA concentrations of IL-8 and MCP-1 during the first 2 weeks of life are associated with the development of BPD . Recovery of Uu from TAs is associated with a more robust inflammatory reaction and an increased risk of BPD. Arch Immunol Ther Exp (Warsz), 2001, 49(3), 217 - 29 CD89: the human myeloid IgA Fc receptor; Morton HC et al.; CD89 (Fc alphaRI) is the human myeloid IgA Fc receptor expressed on cells, such as neutrophils, eosinophils and monocytes/macrophages . Cross-linking of CD89 on these cells, by IgA-opsonised particles (e.g . bacteria, viruses) or anti-CD89 monoclonal antibodies, can trigger various immunological effector functions which are generally protective but may also cause harm to the body . CD89 is a transmembrane glycoprotein that binds both subclasses of IgA in all its molecular forms (i.e . monomeric, dimeric and secretory IgA) via a region of its membrane-distal EC1 domain . DNA studies have shown that the CD89 gene is located within the newly described leukocyte receptor cluster (LRC) on chromosome 19 . CD89 is more closely related to the KIR and MIR proteins, whose genes are also found in the LRC, than to other human Fc receptors (FcRs) . On myeloid cells, CD89 is able to associate with the immunoreceptor tyrosine-based activation motif (ITAM)-containing the FcR gamma chain, which is responsible for intracellular signaling via CD89 . Recently, it has been suggested that some cells express CD89 in a form that does not associate with the FcR gamma chain . Although the biological relevance of this observation is not yet clear, it may explain certain anti-inflammatory/inhibitory effects attributed to IgA . Here we review current knowledge concerning the genetics, structure and biological function of CD89. Environ Sci Technol, 2001 Jul 15, 35(14), 2942 - 8 Siderophore mediated plutonium accumulation by Microbacterium flavescens (JG-9); John SG et al.; Uptake of plutonium and uranium mediated by the siderophore desferrioxamine-B (DFOB) has been studied for the common soil aerobe Microbacterium flavescens(JG-9) . M . flavescens does not bind or take up nitrilotriacetic acid (NTA) complexes of U(VI), Fe(III), or Pu(IV) or U(VI)-DFOB but does take up Fe(III)-DFOB and Pu(IV)-DFOB . Pu(IV)-DFOB and Fe(III)-DFOB accumulations are similar: only living and metabolically active bacteria take up these metal-siderophore complexes . The Fe(III)-DFOB and Pu(IV)-DFOB complexes mutually inhibit uptake of the other, indicating that they compete for shared binding sites or uptake proteins . However, Pu uptake is much slower than Fe uptake, and cumulative Pu uptake is less than Fe, 1.0 nmol of Fe vs 0.25 nmol of Pu per mg of dry weight bacteria . The Pu(IV)-DFOB interactions with M . flavescens suggest that Pu-siderophore complexes could generally be recognized by Fe-siderophore uptake systems of many bacteria, fungi, or plants, thereby affecting Pu environmental mobility and distribution . The results also suggest that the siderophore complexes of tetravalent metals can be recognized by Fe-siderophore uptake proteins. Rheumatology (Oxford), 2001 Jul, 40(7), 801 - 5 Indirect evidence of intra-articular immunoglobulin G synthesis in patients with Chlamydia trachomatis reactive arthritis; Bas S et al.; OBJECTIVES: To investigate whether B-cell stimulation occurs in joints of Chlamydia trachomatis reactive arthritis patients by comparing the immunoglobulin G (IgG) anti-C . trachomatis antibody responses in serum and synovial fluid (SF) . METHODS: The number and spectrum of C . trachomatis antigens recognized by paired serum and SF samples from 16 patien