J Bacteriol, 2003 Jul, 185(14), 4172 - 85 Mycobacterium tuberculosis chaperonin 10 heptamers self-associate through their biologically active loops; Roberts MM et al.; The crystal structure of Mycobacterium tuberculosis chaperonin 10 (cpn10(Mt)) has been determined to a resolution of 2.8 A . Two dome-shaped cpn10(Mt) heptamers complex through loops at their bases to form a tetradecamer with 72 symmetry and a spherical cage-like structure . The hollow interior enclosed by the tetradecamer is lined with hydrophilic residues and has dimensions of 30 A perpendicular to and 60 A along the sevenfold axis . Tetradecameric cpn10(Mt) has also been observed in solution by dynamic light scattering . Through its base loop sequence cpn10(Mt) is known to be the agent in the bacterium responsible for bone resorption and for the contribution towards its strong T-cell immunogenicity . Superimposition of the cpn10(Mt) sequences 26 to 32 and 66 to 72 and E . coli GroES 25 to 31 associated with bone resorption activity shows them to have similar conformations and structural features, suggesting that there may be a common receptor for the bone resorption sequences . The base loops of cpn10s in general also attach to the corresponding chaperonin 60 (cpn60) to enclose unfolded protein and to facilitate its correct folding in vivo . Electron density corresponding to a partially disordered protein subunit appears encapsulated within the interior dome cavity of each heptamer . This suggests that the binding of substrates to cpn10 is possible in the absence of cpn60. Res Microbiol, 2003 Jun, 154(5), 353 - 9 Characterization and identification of an iron-oxidizing, Leptospirillum-like bacterium, present in the high sulfate leaching solution of a commercial bioleaching plant; Romero J et al.; Most copper bioleaching plants operate with a high concentration of sulfate salts, caused by the continuous addition of sulfuric acid and the recycling of the leaching solution . Since the bacteria involved in bioleaching have been generally isolated at low sulfate concentrations, the bacterial population present in the high-sulfate (150 gl(-1)) leaching solution, employed in a copper production plant, was investigated . The iron-oxidizing bacteria able to grow in the leaching solution were enriched by several batch cultivations and, after serial dilution, an abundant bacterial strain was isolated . This strain, called LA, exhibited a relatively constant rate of iron-oxidation in media containing sulfate ions at concentrations ranging from 10 to 150 gl(-1) . Culture collection strains of Leptospirillum ferrooxidans and Acidithiobacillus ferrooxidans showed limited abilities to grow at sulfate ion concentrations higher than 70 gl(-1) . In spite of its tolerance to high sulfate concentrations, strain LA was as sensitive to NaCl as A . ferrooxidans . Comparative sequence analysis of the 16S rRNA gene of strain LA indicated that it is phylogenetically related to strains described as Leptospirillum ferrooxidans . Bacterial community DNA restriction patterns of 16S rRNA genes suggested that strain LA was a minor component of the bacterial population present in leaching solution, but is abundant in ore leached with this solution. J Struct Funct Genomics, 2000, 1(1), 15 - 25 NMR structure determination and structure-based functional characterization of conserved hypothetical protein MTH1175 from Methanobacterium thermoautotrophicum; Cort JR et al.; The solution structure of MTH1175, a 124-residue protein from the archaeon Methanobacterium thermoautotrophicum has been determined by NMR spectroscopy . MTH1175 is part of a family of conserved hypothetical proteins (COG1433) with unknown functions which contains multiple paralogs from all complete archaeal genomes and the archaeal gene-rich bacterium Thermotoga maritima . Sequence similarity indicates this protein family may be related to the nitrogen fixation proteins NifB and NifX . MTH1175 adopts an alpha/beta topology with a single mixed beta-sheet, and contains two flexible loops and an unstructured C-terminal tail . The fold resembles that of Ribonuclease H and similar proteins, but differs from these in several respects, and is not likely to have a nuclease activity. Biosci Biotechnol Biochem, 2003 May, 67(5), 1172 - 6 Escherichia coli tRNAs are resistant to the hyperprocessing reaction of homologous E . coli ribonuclease P ribozyme; Tanaka T et al.; Bacterial ribonuclease P RNA ribozyme can do the hyperprocessing reaction, the internal cleavage reaction of some floppy eukaryotic tRNAs . The hyperprocessing reaction can be used as a detection tool to examine the stability of the cloverleaf shape of tRNA . Until now, the hyperprocessing reaction has been observed in the heterologous combination of eukaryotic tRNAs and bacterial RNase P enzymes . In this paper, we examined the hyperprocessing reaction of Escherichia coli tRNAs by homologous E . coli RNase P, to find that these homologous tRNAs were resistant to the toxic hyperprocessing reaction . Our results display the evidence for molecular co-evolution between homologous tRNAs and RNase P in the bacterium E . coli. Acta Crystallogr D Biol Crystallogr, 2003 Jul, 59(Pt 7), 1280 - 2 Epub 2003 Jun 27. Purification, crystallization and preliminary X-ray analysis of an unusual thioredoxin from the gastric pathogen Helicobacter pylori; Filson H et al.; Thioredoxin-2 (HP1458) from Helicobacter pylori is a member of the thioredoxin family, but possesses the unusual active-site motif CPDC (compared with CGPC in other thioredoxins) . H . pylori is deficient in the glutaredoxin system, making the thioredoxin system the sole reduction system in the bacterium and critical for its ability to survive oxidative stress . The recombinant protein has been overexpressed, purified and crystallized . This is the first reported crystallization of a thioredoxin possessing this unusual active site . Single crystals have been obtained using the sitting-drop technique . Crystals diffract to 2.4 A resolution and belong to space group P4(1), with unit-cell parameters a = b = 40.21, c = 64.65 A . Molecular replacement using AMoRe proved unsuccessful; however, implementation of the program BEAST gave successful molecular-replacement solutions. Genes Dev, 2003 Jul 15, 17(14), 1727 - 40 Epub 2003 Jun 27. The chaplins: a family of hydrophobic cell-surface proteins involved in aerial mycelium formation in Streptomyces coelicolor; Elliot MA et al.; The filamentous bacterium Streptomyces coelicolor differentiates by forming specialized, spore-bearing aerial hyphae that grow into the air . Using microarrays, we identified genes that are down-regulated in a mutant unable to erect aerial hyphae . Through this route, we identified a previously unknown layer of aerial mycelium surface proteins (the "chaplins") . The chaplins share a hydrophobic domain of approximately 40 residues (the "chaplin domain"), and all have a secretion signal . The five short chaplins (ChpD,E,F,G,H) have one chaplin domain, whereas the three long chaplins (ChpA,B,C) have two chaplin domains and a C-terminal "sorting signal" that targets them for covalent attachment to the cell wall by sortase enzyme . Expression of the two chaplin genes examined (chpE, chpH) depended on aerial hyphae formation but not sporulation, and egfp fusions showed their expression localized to aerial structures . Mass spectrometry of cell wall extracts confirmed that the short chaplins localized to the cell surface . Deletion of chaplin genes caused severe delays in aerial hyphae formation, a phenotype rescued by exogenous application of chaplin proteins . These observations implicate the chaplins in aerial mycelium formation, and suggest that coating of the envelope by the chaplins is required for aerial hyphae to grow out of the aqueous environment of the substrate mycelium into the air. Comp Biochem Physiol B Biochem Mol Biol, 2003 Jul, 135(3), 511 - 9 Lysozyme of the beet armyworm, Spodoptera exigua: activity induction and cDNA structure; Bae S et al.; Lysozyme of the beet armyworm, Spodoptera exigua, was characterized in its up-regulation pattern, and its cDNA was cloned by RT-PCR using degenerate primers designed from some conserved amino acid regions shared with related lepidopteran species . Lysozyme activity of the non-immunized S . exigua had developmental variation, with the highest level in the fifth instar larvae . The basal level of the lysozyme activity was significantly enhanced by the injection of laminarin or lipopolysaccharide (LPS) . Among different LPSs tested, the extract from an entomopathogenic bacterium, Xenorhabdus nematophilus, proved to be the most potent . Fat body was the major tissue to express the lysozyme in S . exigua . Even though there was a significantly elevated level of lysozyme in the hemolymph at 12 h after laminarin injection, the transcript ( approximately 1.1 kbp) was found in the fat body as early as 6 h after injection . The cDNA of the lysozyme was cloned as 602 bp with a deduced 141-amino-acid residue open reading frame containing two introns . Except for a signal peptide with 20 amino acid residues, the estimated molecular weight and isoelectric point of the lysozyme was 14313.83 Da and 8.59, respectively . Only a single copy gene of the lysozyme was found in S . exigua genome from Southern analysis . The amino acid sequence of S . exigua lysozyme showed higher similarity (88.7%) with noctuid species compared to other lepidopteran species. Am J Kidney Dis, 2003 Jul, 42(1), 1 - 11 The association of nephrolithiasis with cystic fibrosis; Gibney EM et al.; BACKGROUND: There is a growing body of evidence regarding the association between cystic fibrosis (CF) and nephrolithiasis and the role that Oxalobacter formigenes may have in that association . METHODS: We performed a MEDLINE search of "cystic fibrosis and nephrolithiasis" and "Oxalobacter formigenes." Epidemiological and experimental evidence and possible mechanisms explaining the association were critically reviewed . RESULTS: Of patients with CF, 3.0% to 6.3% are affected with nephrolithiasis, a percentage greater than that of age-matched controls without CF, in whom the rate is 1% to 2% . Studies have suggested possible mechanisms for the association, including hyperuricosuria, hyperoxaluria, primary defects in calcium handling caused by mutation of the CF transmembrane regulator (CFTR), hypocitraturia, and lack of colonization with O formigenes, an enteric oxalate-degrading bacterium . The absence of colonization could be related to frequent courses of antibiotics . CONCLUSION: Although the incidence of stones in patients with CF may be increased compared with controls without CF, many possible mechanisms are implicated . The relative contributions of these mechanisms remain uncertain . Future directions may include specific identification of lithogenic risks and therapy aimed at stone prevention in this population. J Nat Prod, 2003 Jun, 66(6), 883 - 4 A new cyclic peptide from a marine-derived bacterium of the genus Nocardiopsis; Shin J et al.; A new cyclic tetrapeptide (1) was isolated from the culture broth of an actinomycete of the genus Nocardiopsis collected from the Pacific deep-sea sediment . The structure of this compound was determined to be cyclo-(L-isoleucyl-L-prolyl-L-leucyl-L-prolyl) on the basis of combined chemical and spectral methods. Trends Microbiol, 2003 Jun, 11(6), 239 - 42 Taxing questions in development; Armitage JP; Bacteria use taxis-controlled movement to reach their optimum environment . Chemotaxis is probably the best understood behavioural system in biology, biasing the normal random movement of bacteria using a phospho-relay pathway from receptors to the motility organelles . The pathways are typified by signal recognition and receptor adaptation, enabling bacteria to sense and respond to changing environments . Models have been derived from the single chemosensory pathway of Escherichia coli but the sequencing of an increasing number of bacterial genomes is revealing genes that apparently encode multiple chemosensory pathways . Recently, data have accumulated suggesting that some of these pathways might not control motility, although the mechanisms by which this might happen remain unclear . Information from the soil bacterium Myxococcus xanthus could lead the way to an understanding of such mechanisms. Med Vet Entomol, 2003 Jun, 17(2), 232 - 4 The poultry red mite, Dermanyssus gallinae, a potential vector of Erysipelothrix rhusiopathiae causing erysipelas in hens; Chirico J et al.; Erysipelas is a bacterial disease caused by Erysipelothrix rhusiopathiae, which may infect swine as well as several other species of mammals and birds, including domestic fowl . In poultry, erysipelas may cause sudden high mortality due to septicemia . This communication describes the first isolation of E . rhusiopathiae from the haematophagous poultry red mite, Dermanyssus gallinae DeGeer (Acari: Dermanyssidae), that was collected on three farms where hen erysipelas was diagnosed . The bacteria were isolated from the integument as well as from the interior of the mites . Serotypes 1a and 1b of E . rhusiopathiae found in the mites corresponded with those isolated from the diseased birds . These findings imply that D . gallinae is a potential vector of E . rhusiopathiae . The current lack of effective measures to control D . gallinae causes recurring mite problems in poultry facilities once afflicted by this parasite . Consequently, mites containing E . rhusiopathiae may act as reservoir hosts of this bacterium, allowing it to persist in the poultry house between flock cycles as a source of infection for the replacement pullets . The zoonotic potentials of both E . rhusiopathiae and D . gallinae should also be considered. Infect Immun, 2003 Jul, 71(7), 4067 - 78 Soluble extracts from Helicobacter pylori induce dome formation in polarized intestinal epithelial monolayers in a laminin-dependent manner; Terres AM et al.; Helicobacter pylori colonizes the stomach at the interface between the mucus layer and the apical pole of gastric epithelial cells . A number of secreted and shed products from the bacteria, such as proteins and lipopolysaccharide, are likely to have a role in the pathogenesis at the epithelial level . To determine the physiological response of transporting polarized epithelia to released soluble factors from the bacterium, we used the T84 cell line . Monolayers of T84 cells were exposed to soluble extracts from H . pylori . The extracts induced rapid "dome" formation as well as an immediate decrease in transepithelial electrical resistance . Domes are fluid-filled blister-like structures unique to polarized epithelia . Their formation has been linked to sodium-transporting events as well as to diminished adherence of the cells to the substrate . H . pylori-induced dome formation in T84 monolayers was exacerbated by amiloride and inhibited by ouabain . Furthermore, it was associated with changes in the expression of the laminin binding alpha 6 beta 4 integrin and the 67-kDa laminin receptor . Domes formed primarily on laminin-coated filters, rather than on fibronectin or collagen matrices, and their formation was inhibited by preincubating the bacterial extract with soluble laminin . This effect was specific to H . pylori and independent of the urease, vacA, cagA, and Lewis phenotype of the strains . These data indicate that released elements from H . pylori can alter the physiological balance and integrity of the epithelium in the absence of an underlying immune response. Infect Immun, 2003 Jul, 71(7), 4018 - 25 Major surface protein 2 of Anaplasma phagocytophilum facilitates adherence to granulocytes; Park J et al.; Anaplasma phagocytophilum is an obligate intracellular bacterium that infects myeloid cells in the mammalian host . Msp2 (p44) is the major immunodominant outer-membrane protein of these bacteria . We hypothesized that Msp2 acts as an adhesin for A . phagocytophilum entry into granulocytes . This potential role was investigated by blocking binding with Msp2 monoclonal antibodies and by antagonizing binding and propagation with recombinant Msp2 (rMsp2) in vitro . With HL-60 cells, fresh human peripheral blood neutrophils, and a cell line devoid of the fucosylated platelet selectin glycoprotein ligand 1 (PSGL-1) receptor for A . phagocytophilum or one that was transfected to express this ligand, Msp2 monoclonal antibody and rMsp2 used as the antagonist caused concentration-dependent reductions in bacterial adhesion (P < 0.007 and P < 0.02, respectively) and propagation (P < 0.05 and P < 0.001), although inhibition of adhesion or propagation was moderate and incomplete . Likewise, rMsp2 bound to surfaces of the transfected cell at a level similar to that of extracellular A . phagocytophilum and significantly (P < 0.05) beyond that of nontransfected cells . Moreover, a dose-dependent reduction (P < 0.019) in PSGL-1 monoclonal antibody binding to HL-60 cells was elicited with rMsp2 . We conclude that Msp2s of A . phagocytophilum are involved in bacterial adhesion to ligands on host myeloid cells before intracellular infection. Immunity, 2003 Jun, 18(6), 722 - 4 Intracellular pathogens and antigen presentation-new challenges with Legionella pneumophila; Unanue ER; In this issue of Immunity, examine the intracellular life of Legionella pneumophila in dendritic cells (DC) and macrophages, as well as the presentation of its antigens to CD4 T cells . Legionella is a particularly interesting bacterium because of the peculiarities inherent in its intracellular sojourn in phagocytes: it resides in an unusual vesicle characterized by ribosomes studded along its walls . In this compartment, Legionella proteins encoded by the dot gene inhibit phagosome-lysosome fusion and endosomal acidification, yielding a vesicular structure conducive to the multiplication of Legionella, poor in lysosomal contents, and in MHC molecules. Philos Transact A Math Phys Eng Sci, 2003 Jun 15, 361(1807), 1089 - 99 Molecular autonomous agents; Kauffman S; I consider an autonomous agent to be a physical system able to act on its own behalf, such as a bacterium swimming up a glucose gradient . I tentatively define an autonomous agent to be a system capable of self-reproduction and at least capable of performing one thermodynamic work cycle . I give a hypothetical chemical example . I then explore the increasingly odd implications of this definition. J Neurosurg, 2003 Jun, 98(6), 1198 - 202 Clinical application of a physically and chemically processed human substitute for dura mater; Dufrane D et al.; OBJECT: Allogenic human fascia lata used in neurosurgery as a dura mater substitute can be associated with the risk of virus and bacterium transmission and with a delay in its incorporation due to immunological and inflammatory reactions . The authors review their preliminary experience with a chemically and physically processed fascia lata graft . METHODS: Grafts that had been treated with solvent detergents, freeze-dried for conservation, and gamma irradiated (25,000 Gy) for sterilization were placed into 17 patients during neurosurgical procedures performed to treat brain tumors, cerebral malformations, trigeminal neuralgia, and posttraumatic lesions . The handling properties of the material, surgical wound features, and hematological parameters were evaluated . The average follow-up period was 23.8 +/- 2.2 months (mean +/- standard deviation) . The handling properties and biocompatibility of these human dural substitutes were highly satisfactory and no major complications were observed . Postoperative computerized tomography or magnetic resonance images obtained in 13 patients revealed no abnormal findings at the site of fascia lata implantation . In one patient who underwent a second surgery performed 12 months after the initial operation, this dural substitute was found to have been recolonized by host fibroblastic cells and replaced by autologous collagenous tissue . CONCLUSIONS: Human fascia lata that has been rendered safe by applying physical and chemical treatment is a fully biocompatible alternative to the dural graft materials currently available. Izv Akad Nauk Ser Biol, 2003 May-Jun, (3), 301 - 5 {Isolation, purification, and properties of malate dehydrogenases from sulfur bacteria Beggiatoa leptomitiformis}; Eprintsev AT et al.; Malate dehydrogenase (E.C . 1.1.1.37) from bacterium Beggiatoa leptomitiformis was isolated and purified 123 times using a five-step purification procedure including the enzyme extraction, ammonium sulfate protein fractionation, gel filtration, ion exchange chromatography, and gel chromatography . The enzyme was homogenous according to the electrophoresis data; its activity was 20.43 U/mg proteins . This malate dehydrogenase is a homotetramer (Mr = 172 kDa) . The catalytic and thermodynamic properties, as well as the analysis of the published data suggest that the tetrameric structure of the enzyme allows it to participate in constructive metabolism supplying the cell with organic acids as a source of carbon. Microbes Infect, 2003 Jul, 5(8), 741 - 8 Animal models of Helicobacter pylori infection and disease; O'Rourke JL et al.; The acceptance of Helicobacter pylori as a major human pathogen has necessitated the development of animal models to help elucidate the pathogenic mechanisms of this bacterium and aid in the development of improved strategies for the treatment of gastric disease . Appropriate models, utilising a range of animal species, have been developed to examine factors such as the influence of host responses and bacterial factors in disease development and the success of new therapeutic regimens, including vaccination, to cure infection. Microbes Infect, 2003 Jul, 5(8), 715 - 21 Molecular and cellular mechanisms of action of the vacuolating cytotoxin (VacA) and neutrophil-activating protein (HP-NAP) virulence factors of Helicobacter pylori; Montecucco C et al.; Helicobacter pylori has elaborated a unique set of virulence factors that allow it to colonise the stomach wall . These factors include urease, helicoidal shape, flagella and adhesion molecules . Here we discuss the molecular characteristics and mechanisms of action of the vacuolating cytotoxin, VacA, and the neutrophil-activating protein, HP-NAP . Their activities are discussed in terms of tissue alterations, which promote the release of nutrients necessary for the growth and survival of the bacterium in its nutrient-poor ecological niche. Cell Microbiol, 2003 Jul, 5(7), 469 - 80 Maturation of the Coxiella burnetii parasitophorous vacuole requires bacterial protein synthesis but not replication; Howe D et al.; This study examined whether protein synthesis and replication are required for maturation and fusogenicity of the lysosomal-like, large and spacious parasitophorous vacuole (PV) of Coxiella burnetii, an obligate intracellular bacterium . Large and spacious PV with multiple non-replicating C . burnetii were observed by phase microscopy in Vero cells infected at a multiplicity of infection of ten and treated with a bacteriostatic concentration of nalidixic acid or carbenicillin, antimicrobics that inhibit DNA and cell wall biosynthesis respectively . Conversely, large and spacious PV were not observed in cells treated with a bacteriostatic concentration of the protein synthesis inhibitor chloramphenicol . Rather, fluorescence microscopy of individual cells revealed multiple, acidic PV harbouring a single organism tightly bounded by a LAMP-1 positive vacuolar membrane . These vacuoles homotypically fused to form a large and spacious PV upon removal of the drug . Chloramphenicol also inhibited trafficking of latex beads to large and spacious PV and caused mature PV to collapse . Collectively, these results demonstrate that C . burnetii protein synthesis, but not replication, is required for fusion between nascent C . burnetii PV and latex bead phagosomes, and also for formation and maintenance of large and spacious, replicative PV . However, transit of nascent PV through the endocytic pathway to ultimately acquire lysosomal markers appears to occur irrespective of Coxiella protein synthesis. J Bacteriol, 2003 Jul, 185(13), 3780 - 7 Common and distinguishing regulatory and expression characteristics of the highly related KorB proteins of streptomycete plasmids pIJ101 and pSB24.2; Ducote MJ et al.; The conjugative plasmid pIJ101 of the spore-forming bacterium Streptomyces lividans contains a regulatory gene, korB, whose product is required to repress potentially lethal expression of the pIJ101 kilB gene . The KorB protein also autoregulates korB gene expression and may be involved in control of pIJ101 copy number . KorB (pIJ101) is expressed as a 10-kDa protein in S . lividans that is immediately processed to a mature 6-kDa repressor molecule . The conjugative Streptomyces cyanogenus plasmid pSB24.1 is deleted upon entry into S . lividans to form pSB24.2, a nonconjugative derivative that contains a korB gene nearly identical to that of pIJ101 . Previous evidence that korB of pSB24.2 is capable of overriding pIJ101 kilB-associated lethality supported the notion that pIJ101 and pSB24.2 encode highly related, perhaps even identical conjugation systems . Here we show that KorB (pIJ101) and KorB (pSB24.2) repress transcription from the pIJ101 kilB promoter equally well, although differences exist with respect to their interactions with kilB promoter sequences . Despite high sequence and functional similarities, KorB (pSB24.2) was found to exist as multiple stable forms ranging in size from 10 to 6 kDa both in S . lividans and S . cyanogenus . Immediate processing of KorB (pIJ101) exclusively to the 6-kDa repressor form meanwhile was conserved between the two species . A feature common to both proteins was a marked increase in expression or accumulation upon sporulation, an occurrence that may indicate a particular need for increased quantities of this regulatory protein upon spore germination and resumption of active growth of plasmid-containing cells. J Environ Qual, 2003 May-Jun, 32(3), 751 - 9 Leaching characteristics of heavy metals from sewage sludge by Acidithiobacillus thiooxidans MET; Ryu HW et al.; An acidophilic, sulfur-oxidizing Acidithiobacillus thiooxidans MET bacterium was isolated from anaerobically digested, dewatered sewage sludge . This bacterium showed sulfur-oxidizing ability at both acidic and neutral conditions, and allowed metal leaching even at a high (130 g L(-1)) sludge solids concentration . We found that low metal leaching efficiency at high solids concentration was mainly due to an increase in buffering capacity resulting in retardation of pH reduction . Therefore, metal leaching was mainly influenced not by sludge solids concentration, but by the pH (or sulfate concentration per unit sludge mass) of the sludge solutions . The relationship between the pH of the sludge solution and the efficiency of metal leaching was obtained by quantitatively investigating the effect of pH reduction or the amount of sulfate produced per unit sludge mass on leaching of each metal . Furthermore, the relationship between total metal content in the sludge and metal leached to the solution was obtained for each metal . Such a relationship allowed estimation of leachable metal at various amounts of total metal content in sludge. J Cell Sci, 2003 Jul 15, 116(Pt 14), 3017 - 26 Stimulation of MMP-7 (matrilysin) by Helicobacter pylori in human gastric epithelial cells: role in epithelial cell migration; Wroblewski LE et al.; Epithelial cell responses to bacterial infection include induction of matrix metalloproteinase 7 (MMP-7) . Here, we identify increased MMP-7 expression in the gastric epithelium in response to the oncogenic bacterium Helicobacter pylori, and report on the mechanisms and consequences for gastric epithelial cell migration . In patients infected with H . pylori, there was increased MMP-7 in gastric biopsies detected by western blot . MMP-7 was localized to the advancing edge of migrating gastric epithelial cell colonies, including lamellipodia . Rates of spreading of gastric gland cells were higher in H . pylori-infected cultures compared with control, and this was inhibited by antisense oligonucleotides to MMP-7 . Complementary data were obtained in a gastric cancer cell line (AGS cells) . In the latter, H . pylori induced expression of an MMP-7-luciferase promoter/reporter vector through mechanisms that involved activation of Rho and Rac . RhoA acted through activation of both NF-kappaB and AP-1, whereas Rac activated NF-kappaB but not AP-1 . MMP-7 is commonly upregulated in gastric cancer; since H . pylori is a recognized gastric carcinogen, the data suggest a new mechanism by which the bacterium might predispose towards gastric neoplasia. Commun Dis Intell, 2003, 27 Suppl, S127 - 31 Surveillance for antibiotic resistance in veterinary pathogens from the perspective of a regional diagnostic laboratory; Stephens CP; The Toowoomba Veterinary Laboratory tests for antibiotic resistance through passive surveillance of bacterial pathogens from diseased, frequently intensively managed, animals . Testing is carried out on the basis of the number of animals involved, the nature and severity of the disease and the identity and significance of the bacterium, the results guiding the submitting veterinarian in implementing appropriate treatment . The antibiotics chosen for testing are those that are currently registered for veterinary use and are considered effective in the given situation . Testing is carried out according to the current National Committee for Clinical Laboratory Standards Approved Standard for Disc Susceptibility Tests . This paper presents some results of testing bacterial pathogens from cattle and pigs. Int J Syst Evol Microbiol, 2003 May, 53(Pt 3), 787 - 93 Description of Sulfurospirillum halorespirans sp . nov., an anaerobic, tetrachloroethene-respiring bacterium, and transfer of Dehalospirillum multivorans to the genus Sulfurospirillum as Sulfurospirillum multivorans comb . nov; Luijten ML et al.; An anaerobic, halorespiring bacterium (strain PCE-M2(T) = DSM 13726(T) = ATCC BAA-583(T)) able to reduce tetrachloroethene to cis-dichloroethene was isolated from an anaerobic soil polluted with chlorinated aliphatic compounds . The isolate is assigned to the genus Sulfurospirillum as a novel species, Sulfurospirillum halorespirans sp . nov . Furthermore, on the basis of all available data, a related organism, Dehalospirillum multivorans DSM 12446(T), is reclassified to the genus Sulfurospirillum as Sulfurospirillum multivorans comb . nov. Genome Res, 2003 Jul, 13(7), 1665 - 74 Epub 2003 Jun 12. Systematic cloning of Treponema pallidum open reading frames for protein expression and antigen discovery; McKevitt M et al.; A topoisomerase-based method was used to clone PCR products encoding 991 of the 1041 open reading frames identified in the genome sequence of the bacterium that causes syphilis, Treponema pallidum subsp . pallidum . Cloning the open reading frames into the univector plasmid system permitted the rapid conversion of the original clone set to other functional vectors containing a variety of promoters or tag sequences . A computational prediction of signal sequences identified 248 T . pallidum proteins that are potentially secreted from the cell . These clones were systematically converted into vectors designed to express the encoded proteins as glutathione-S-transferase fusion proteins . To test the potential of the clone set for novel antigen discovery, 85 of these fusion proteins were expressed from Escherichia coli, partially purified, and tested for antigenicity by using sera from rabbits infected with T . pallidum . Twelve of the 85 proteins bound significant levels of antibody . Of these 12 proteins, seven had previously been identified as T . pallidum antigens, and the remaining five represent novel antigens . These results demonstrate the potential of the T . pallidum clone set for antigen discovery and, more generally, for advancing the biology of this enigmatic spirochete. Blood, 2003 Oct 1, 102(7), 2692 - 4 Epub 2003 Jun 12. Persistent Mycobacterium avium infection following nonmyeloablative allogeneic peripheral blood stem cell transplantation for interferon-gamma receptor-1 deficiency; Horwitz ME et al.; Interferon-gamma receptor-1 (IFNgammaR1) deficiency is a rare inherited immunodeficiency . We performed a nonmyeloablative allogeneic stem cell transplantation on a boy with complete IFNgammaR1 deficiency and refractory disseminated Myco- bacterium avium infection . Despite the patient's profound immune defect, early donor stem cell engraftment was low . Full donor engraftment was accomplished only following multiple donor lymphocyte infusions . Detection of IFNgammaR1 expression on peripheral blood monocytes and neutrophils corresponded with establishment of stable, complete donor hematopoietic chimerism . However, expression of, and signaling through IFNgammaR1 disappeared shortly thereafter . Disseminated Mycobacterium avium infection persisted and the patient died . Coculture of Myco- bacterium avium with normal myeloid cells resulted in an IFNgamma signaling defect similar to that observed in vivo . Active disseminated Mycobacterium avium infection may significantly compromise normal immune reconstitution following allogeneic stem cell transplantation . Patients with IFNgammaR1 deficiency should receive transplants before developing refractory mycobacterial infections. FEBS Lett, 2003 Jun 19, 545(2-3), 120 - 6 Structural and functional analysis of a lycopene beta-monocyclase gene isolated from a unique marine bacterium that produces myxol; Teramoto M et al.; A gene coding for lycopene beta-monocyclase, which metabolizes lycopene (psi,psi-carotene) to gamma-carotene (beta,psi-carotene), was isolated for the first time from a unique marine bacterium strain P99-3 that produces myxol (a gamma-carotene derivative) . This lycopene beta-monocyclase gene (designated crtYm) was included in the gene cluster which contained carotenoid biosynthetic gene (crtI, crtB, crtZ, crtY, and crtA) homologs . CrtYm, the CrtY homolog, metabolized lycopene to gamma-carotene, which was confirmed by deletion/expression analysis of the crtYm and by subsequent analysis of the metabolites from lycopene based on the retention times on high-performance liquid chromatography, UV-visible absorption spectra, and mass spectrometry. Lett Appl Microbiol, 2003, 37(1), 21 - 5 Overlapping role of the outer membrane cytochromes of Shewanella oneidensis MR-1 in the reduction of manganese(IV) oxide; Myers JM et al.; AIM: To determine if the outer membrane (OM) cytochromes OmcA and OmcB of the metal-reducing bacterium Shewanella oneidensis MR-1 have distinct or overlapping roles in the reduction of insoluble manganese(IV) oxide . METHODS AND RESULTS: The gene replacement mutant (OMCA1) which lacks OmcA was partially deficient in Mn(IV) reduction . Complementation of OMCA1 with a vector (pVK21) that contains omcB but not omcA restored Mn(IV) reduction to levels that were even greater than those of wild-type . Examination of the OM of OMCA1/pVK21 revealed greater than wild-type levels of OmcB protein and specific haem content . CONCLUSIONS: Overexpression of OmcB can compensate for the absence of OmcA in the reduction of insoluble Mn(IV) oxides . Therefore, there is at least a partial overlap in the roles of these OM cytochromes in the reduction of insoluble Mn(IV) oxide . SIGNIFICANCE: The overlapping roles of these two cytochromes has important implications for understanding the mechanism by which MR-1 reduces insoluble metal oxides . There is no obligatory sequential electron transfer from one cytochrome to the other . They could both potentially serve as terminal reductases for extracellular electron acceptors. Arch Biochem Biophys, 2003 Jul 1, 415(1), 87 - 93 Unique metal dependency of cytosolic alpha-mannosidase from Thermotoga maritima, a hyperthermophilic bacterium; Nakajima M et al.; A putative cytosolic alpha-mannosidase gene from a hyperthermophilic marine bacterium Thermotoga maritima was cloned and expressed in Escherichia coli . The purified recombinant enzyme appeared to be a homodimer of a 110-kDa subunit . The enzyme showed metal-dependent ability to hydrolyze p-nitrophenyl-alpha-D-mannopyranoside . In the absence of a metal, the enzyme was inactive . Cobalt and cadmium supported high activity (60 U/mg at 70 degrees C), while the activity with zinc and chromium was poor . Cobalt (0.8 mol) bound to 1 mol monomer with a K(d) of 70 microM . The optimum pH and temperature were 6.0 and 80 degrees C, respectively . The activity was inhibited by swainsonine, but not by 1-deoxymannojirimycin, which is in agreement with the features of cytosolic alpha-mannosidase. Crit Rev Oral Biol Med, 2003, 14(3), 226 - 33 Oral Helicobacter pylori: can we stomach it? Dowsett SA, Kowolik MJ. Helicobacter pylori infection is one of the most common in man . The bacterium primarily resides in the human stomach, where it plays a significant role in gastric disease . If the spread of H . pylori is to be prevented, an understanding of the transmission process is essential . The oral cavity has been proposed as a reservoir for gastric H . pylori, which has been detected by culture and PCR in both dental plaque and saliva . This review will discuss the evidence for the role of the oral cavity in the transmission of gastric H . pylori . Moreover, the difficulties encountered in addressing this topic, possible directions for future research, and the implications for the dental profession are discussed. Vaccine, 2003 Jun 20, 21(21-22), 2911 - 22 Porcine Ig isotypes: function and molecular characteristics; Crawley A et al.; In pigs, protection against the toxigenic extra-cellular bacterium Actinobacillus pleuropneumoniae was correlated with an increased IgG(1):IgG(2) ratio of haemolytic toxin-specific antibodies . In all species so far studied, IgG isotype expression is controlled by Type 1 (IFN-gamma, IL-12) and Type 2 (IL-4, IL-10) cytokines which dictate immune response polarization to cell-mediated (CMI) or antibody-mediated immunity (AMI), respectively . Thus, immunoglobulin (Ig) isotypes reflect Type 1 or Type 2 immune responses . Immunoglobulin isotype production by porcine B-cells cultured in the presence of recombinant porcine (rp) cytokines varies by individual, however pigs tend to generate a high IgG(1):IgG(2) ratio in response to rp IL-10 and the inverse in response to rp IFN-gamma or rp IL-12 . Differential Ig isotype production should favor an isotype with a functional advantage to control the inciting infection and disease . However, functions of porcine Ig isotypes have not been described . To compare function of porcine IgM, IgG(1) and IgG(2) of defined specificity for hen eggwhite lysozyme (HEWL), Ig isotypes were affinity purified from serum by HEWL specificity and by isotype-specific mouse monoclonal antibodies . Their ability to activate complement (C') and to opsonize was tested in vitro . Porcine IgG(2) had greater guinea pig C' activating ability than did IgG(1) . Neither isotype opsonized HEWL-conjugated sheep erythrocytes in vitro . Amino acid sequence analysis of IgG isotypes revealed that all subclasses have putative C' binding sites but that IgG(2a), IgG(2b) and IgG(4) were more flexible in the middle hinge region than IgG(1) and IgG(3) and would likely activate C' more efficiently . Thus, porcine IgG isotypes associated with resistance and susceptibility to disease also differ in their actual and predicted biological functions. J Biol Chem, 2003 Sep 12, 278(37), 35384 - 93 Epub 2003 Jun 09. Activation mechanism of the CO sensor CooA . Mutational and resonance Raman spectroscopic studies; Coyle CM et al.; CooA is a CO-dependent heme protein transcription factor of the bacterium Rhodospirillum rubrum . CO binding to its heme causes CooA to bind DNA and activate expression of genes for CO metabolism . To understand the nature of CO activation, several CooA mutational variants have been studied by resonance Raman spectroscopy, in vivo activity measurements, and DNA binding assays . Analysis of the Fe-C and C-O stretching Raman spectroscopy bands permits the conclusion that when CO displaces the Pro2 heme ligand, the protein forms a hydrophobic pocket in which the C-helix residues Gly117, Leu116, and Ile113 are close to the bound CO . The displaced Pro2 terminus is expelled from this pocket, unless the pH is raised above the pKa, in which case the terminus remains in H-bond contact . The pKa for this transition is 8.6, two units below that of aqueous proline, reflecting the hydrophobic nature of the pocket . The proximal Fe-His bond in Fe{II}CooA is as strong as it is in myoglobin but is weakened by CO binding, an effect attributable to loss of an H-bond from the proximal His77 ligand to the adjacent Asn42 side chain . A structural model is proposed for the position of the CO-bound heme in the active form of CooA, which has implications for the mechanism of CO activation. J Am Acad Dermatol, 2003 Jun, 48(6), 966 - 9 Culture and immunohistochemical evidence of Chlamydia pneumoniae infection in ulcerative pyoderma gangrenosum; Sams HH et al.; A potentially contributing factor to the development and chronicity of pyoderma gangrenosum is infection with the relatively recently characterized human pathogen, Chlamydia pneumoniae . C pneumoniae is an obligate intracellular bacterium that can infect endothelial, monocyte, and smooth muscle cells and is associated with cardiopulmonary diseases . A case of serologically, polymerase chain reaction-positive, immunohistochemically, and culture-documented viable C pneumoniae organisms in a chronic pyoderma gangrenosum ulcer is reported, a finding that has not been described previously. Appl Environ Microbiol, 2003 Jun, 69(6), 3646 - 9 Characterization of the first molluscicidal lipopolysaccharide from Moraxella osloensis; Tan L et al.; Moraxella osloensis is a bacterium that is mutualistically associated with Phasmarhabditis hermaphrodita, a nematode that has potential for the biocontrol of mollusk pests, especially the slug Deroceras reticulatum . We discovered that purified M . osloensis lipopolysaccharide (LPS) possesses a lethal toxicity to D . reticulatum when administered by injection but no contact or oral toxicity to this slug . The toxicity of the LPS resides in the lipid A moiety . M . osloensis LPS was semiquantitated at 6 x 10(7) endotoxin units per mg . The LPS is a rough-type LPS with an estimated molecular weight of 5,300 . Coinjection of galactosamine with the LPS increased the LPS's toxicity to the slug two- to four-fold . The galactosamine-induced sensitization of the slug to the LPS was reversed completely by uridine. Appl Environ Microbiol, 2003 Jun, 69(6), 3093 - 102 Genes involved in the biosynthesis of photosynthetic pigments in the purple sulfur photosynthetic bacterium Thiocapsa roseopersicina; Kovacs AT et al.; A pigment mutant strain of the purple sulfur photosynthetic bacterium Thiocapsa roseopersicina BBS was isolated by plasposon mutagenesis . Nineteen open reading frame, most of which are thought to be genes involved in the biosynthesis of carotenoids, bacteriochlorophyll, and the photosynthetic reaction center, were identified surrounding the plasposon in a 22-kb-long chromosomal locus . The general arrangement of the photosynthetic genes was similar to that in other purple photosynthetic bacteria; however, the locations of a few genes occurring in this region were unusual . Most of the gene products showed the highest similarity to the corresponding proteins in Rubrivivax gelatinosus . The plasposon was inserted into the crtD gene, likely inactivating crtC as well, and the carotenoid composition of the mutant strain corresponded to the aborted spirilloxanthin pathway . Homologous and heterologous complementation experiments indicated a conserved function of CrtC and CrtD in the purple photosynthetic bacteria . The crtDC and crtE genes were shown to be regulated by oxygen, and a role of CrtJ in aerobic repression was suggested. J Biochem Mol Biol, 2003 May 31, 36(3), 282 - 7 Production of superoxide dismutase by Deinococcus radiophilus; Yun YS et al.; The production of superoxide dismutase (SOD) varied in Deinococcus radiophilus, the UV resistant bacterium, depending upon different phases of growth, UV irradiation, and superoxide treatment . A gradual increase in total SOD activity occurred up to the stationary phases . The electrophoretic resolution of the SOD in cell extracts of D . radiophilus at each growth phase revealed the occurrence of MnSOD throughout the growth phases . The SOD profiles of D . radiophilus at the exponential phase received oxidative stress by the potassium superoxide treatment or UV irradiation also revealed the occurrence of a single SOD . However, these treatments caused an increase in SOD activity . The data strongly suggest that D . radiophilus has only one species of SOD as a constitutive enzyme, which seems to be a membrane-associated protein. Mol Microbiol, 2003 Jun, 48(5), 1317 - 23 The DNA excision repair system of the highly radioresistant bacterium Deinococcus radiodurans is facilitated by the pentose phosphate pathway; Zhang YM et al.; Deinococcus radiodurans is highly resistant to radiation and mutagenic chemicals . Mutants defective in the putative glucose-6-phosphate dehydrogenase gene (zwf-) and the aldolase gene (fda-) were generated by homologous recombination . These mutants were used to test the cells' resistance to agents that cause dimer formation and DNA strand breaks . The zwf - mutants were more sensitive to agents that induce DNA excision repair, such as UV irradiation and H2O2, but were as resistant to DNA strand break-causing agents such as methylmethanesulphonic acid (MMS) and mitomycin C (MMC) as the wild-type cells . Analysis of the cytoplasmic fraction of zwf- cells showed that the concentrations of inosine monophosphate (IMP) and uridine monophosphate (UMP) were only 30% of those found in the wild-type cells . The fda- mutants were slightly more resistant to UV light and H2O2 . Results suggested that the deinococcal pentose phosphate pathway augmented the DNA excision repair system by providing cells with adequate metabolites for the DNA mismatch repair. Aliment Pharmacol Ther, 2003 Jun, 17 Suppl 2, 75 - 81 Review article: molecular basis of gastric carcinogenesis; Nardone G; Gastric cancer is constituted by two histomorphological entities 'intestinal' and 'diffuse', however lesions with similar morphologies may differ in biological aggressiveness and response to therapy . Two distinct molecular pathways have been identified in gastric carcinogenesis: the microsatellite mutator phenotype and a phenotype associated with chromosomal and intrachromosomal instability . Mounting evidence suggests that microsatellite mutator phenotype alterations and expression of the products of cancer-related genes are early markers of cell transformation, and may serve to identify the gastric carcinoma histotypes . The lack of a clear genetic basis, lends weight to the notion that gastric cancer is not a monomorphic entity but may be affected by environmental factors . Helicobacter pylori is the most important environmental risk factor associated with sporadic gastric cancer . Exposure of gastric epithelial cells to bacterium results in the generation of reactive oxygen species and inducible nitric oxide synthase that in turn may cause genetic alterations leading to cancer in a subset of subjects . Thus, gastric cancer may be considered the result of an interplay between host genetic profile and environmental toxic agents . The new technologies of molecular analysis will help to establish an individual's risk of developing gastric cancer and will lead to novel biological therapeutic strategies. Environ Sci Technol, 2003 May 15, 37(10), 2173 - 83 Role of lipopolysaccharides in the adhesion, retention, and transport of Escherichia coli JM109; Abu-Lail NI et al.; The role of lipopolysaccharides (LPS) in bacterial adhesion was investigated via atomic force microscopy (AFM) . Adhesion between a silicon nitride tip and Escherichia coli JM109 was measured in water and 0.01 M phosphate-buffered saline (PBS) on untreated cells and on a sample of E . coli treated with 100 mM ethylenediaminetetraacetic acid (EDTA), which removes approximately 80% of the LPS molecules . LPS removal decreased the adhesion affinity between the bacterial cells and the AFM tip from -2.1 +/- 1.8 to -0.40 +/- 0.36 nN in water and from -0.74 +/- 0.44 to -0.46 +/- 0.23 nN in 0.01 M PBS (statistically different, Mann-Whitney rank sum test, P < 0.01) . The distributions of adhesion affinities between E . coli LPS macromolecules and the AFM tip could be described by gamma distribution functions . Direct measurements of the adhesive force between E . coil and a surface were compared with adhesion in batch and column experiments, and agreement was observed between the influences of LPS on adhesion in each system . Bacterial batch retention to glass or in packed beds to quartz sand decreased after LPS removal . When interaction forces were measured during the approach of the AFM tip to a bacterium, steric repulsive forces were seen for both treated and untreated cells, but the repulsion was greater when the LPS was intact A model for steric repulsion predicted a reduction of the equilibrium length of the surface polymers from 242 to 64 nm in water and from 175 to 81 nm in buffer, after removal of a portion of the LPS . DLVO calculations based on conventional and soft-particle DLVO theories predicted higher energy barriers to adhesion for all surfaces after LPS removal, consistent with experimental findings . Adhesion forces between the AFM tip and bacterial polymers were correlated with bacterial attachment and retention, while measurements of interaction forces during the approach of the AFM tip to the bacterium did not correlate with subsequent adhesion behavior to glass or quartz sand. Curr Microbiol, 2003 Jul, 47(1), 1 - 4 Monitoring the uptake of protein-derived peptides by Porphyromonas gingivalis with fluorophore-labeled substrates; Yoshioka M et al.; The aim of this study was to develop a simple method to quantify peptide uptake by the periodontopathogenic bacterium Porphyromonas gingivalis . After incubation of bacterial cells with self-quenched fluorescent bovine serum albumin (DQ Green BSA), the fluorescence measured in the supernatant of the assay mixture indicated the degree of protein degradation, whereas the fluorescence associated with the lysate of washed cells indicated the amount of BSA-derived fragments incorporated by the bacteria . The optimal conditions for uptake of fluorophore-labeled albumin fragments were found to be mid-log grown cells, 150 m M NaCl in phosphate buffer, pH 7, 37 degrees C, and anaerobiosis . Among the protease inhibitors tested, 4-(2-aminoethyl)-benzene sulfonyl-fluoride hydrochloride (AEBSF) and cathepsin B inhibitor II caused a significant inhibition of the uptake of BSA-derived peptides . This assay was applicable for other commercially available fluorescent substrates . This simple method may be useful to investigate protein processing in proteolytic bacteria and for studying the effects of environmental parameters or cell treatments on the peptide uptake. Biochemistry, 2003 Jun 10, 42(22), 6726 - 34 Spectroscopic and mutational analysis of the blue-light photoreceptor AppA: a novel photocycle involving flavin stacking with an aromatic amino acid; Kraft BJ et al.; The flavoprotein AppA is a blue-light photoreceptor that functions as an antirepressor of photosynthesis gene expression in the purple bacterium Rhodobacter sphaeroides . Heterologous expression studies show that FAD binds to a 156 amino acid N-terminal domain of AppA and that this domain is itself photoactive . A pulse of white light causes FAD absorption to be red shifted in a biphasic process with a fast phase occurring in <1 micros and a slow phase occurring at approximately 5 ms . The absorbance shift was spontaneously restored over a 30 min period, also in a biphasic process as assayed by fluorescence quenching and electronic absorption analyses . Site-directed replacement of Tyr21 with Leu or Phe abolished the photochemical reaction implicating involvement of Tyr21 in the photocycle . Nuclear magnetic resonance analysis of wild-type and mutant proteins also indicates that Tyr21 forms pi-pi stacking interactions with the isoalloxazine ring of FAD . We propose that photochemical excitation of the flavin results in strengthening of a hydrogen bond between the flavin and Tyr 21 leading to a stable local conformational change in AppA. Acta Crystallogr D Biol Crystallogr, 2003 Jun, 59(Pt 6), 1012 - 5 Epub 2003 May 23. Solving the phase problem for carbohydrate-binding proteins using selenium derivatives of their ligands: a case study involving the bacterial F17-G adhesin; Buts L et al.; The Escherichia coli adhesin F17-G is a carbohydrate-binding protein that allows the bacterium to attach to the intestinal epithelium of young ruminants . The structure of the 17 kDa lectin domain of F17-G was determined using the anomalous dispersion signal of a selenium-containing analogue of the monosaccharide ligand N-acetyl-d-glucosamine in which the anomeric oxygen was replaced by an Se atom . A three-wavelength MAD data set yielded good experimental phases to 2.6 A resolution . The structure was refined to 1.75 A resolution and was used to solve the structures of the ligand-free protein and the F17-G-N-acetyl-d-glucosamine complex . This selenium-carbohydrate phasing method could be of general use for determining the structures of carbohydrate-binding proteins. Microbiology, 2003 Jun, 149(Pt 6), 1423 - 35 The senX3-regX3 two-component regulatory system of Mycobacterium tuberculosis is required for virulence; Parish T et al.; Two-component regulatory systems have been widely implicated in bacterial virulence . To investigate the role of one such system in Mycobacterium tuberculosis, a strain was constructed in which the senX3-regX3 system was deleted by homologous recombination . The mutant strain (Tame15) showed a growth defect after infection of macrophages and was attenuated in both immunodeficient and immunocompetent mice . Competitive hybridization of total RNA from the wild-type and mutant strains to a whole-genome microarray was used to identify changes in gene expression resulting from the deletion . One operon was highly up-regulated in the mutant, indicating that regX3 probably has a role as a repressor of this operon . Other genes which were up- or down-regulated were also identified . Many of the genes showing down-regulation are involved in normal growth of the bacterium, indicating that the mutant strain is subject to some type of growth slow-down or stress . Genes showing differential expression were further grouped according to their pattern of gene expression under other stress conditions . From this analysis 50 genes were identified which are the most likely to be controlled by RegX3 . Most of these genes are of unknown function and no obvious motifs were found upstream of the genes identified . Thus, it has been demonstrated that the senX3-regX3 two-component system is involved in the virulence of M . tuberculosis and a number of genes controlled by this system have been identified. Vet Hum Toxicol, 2003 Jun, 45(3), 160 - 2 Poisoning of livestock in oregon in the 1940s to 1960s attributed to corynetoxins produced by Rathayibacter in nematode galls in chewings fescue (Festuca nigrescens); Riley IT et al.; Tunicaminyluracil antibiotics, similar to the corynetoxins produced by Rathayibacter toxicus in Australia and South Africa, were found in old nematode seed-galls from Festuca nigrescens from New Jersey (USA) and New Zealand (NZ) . The toxin profiles from the NZ and USA galls were similar to each other, but differed from those produced by R toxicus from Australia and South Africa, suggesting that a geographical variant of R toxicus or closely related species may be involved . The NZ galls gave a positive response to a R toxicus-specific monoclonal antibody assay, albeit a considerably weaker response than that seen with Australian R toxicus galls, but the older USA galls were negative, possibly due to deterioration of the antigen . From these findings, it is postulated that livestock deaths associated with the feeding of nematode and bacterial infected screenings of F nigrescens in Oregon, USA, in the 1940s to 1960s were caused by corynetoxin-like toxins produced by the bacterium. Biochem J, 2003 Sep 1, 374(Pt 2), 529 - 35 Hydride transfer during catalysis by dihydrofolate reductase from Thermotoga maritima; Maglia G et al.; DHFR (dihydrofolate reductase) catalyses the metabolically important reduction of 7,8-dihydrofolate by NADPH . DHFR from the hyperthermophilic bacterium Thermotoga maritima (TmDHFR), which shares similarity with DHFR from Escherichia coli, has previously been characterized structurally . Its tertiary structure is similar to that of DHFR from E . coli but it is the only DHFR characterized so far that relies on dimerization for stability . The midpoint of the thermal unfolding of TmDHFR was at approx . 83 degrees C, which was 30 degrees C higher than the melting temperature of DHFR from E . coli . The turnover and the hydride-transfer rates in the kinetic scheme of TmDHFR were derived from measurements of the steady-state and pre-steady-state kinetics using absorbance and stopped-flow fluorescence spectroscopy . The rate constant for hydride transfer was found to depend strongly on the temperature and the pH of the solution . Hydride transfer was slow (0.14 s(-1) at 25 degrees C) and at least partially rate limiting at low temperatures but increased dramatically with temperature . At 80 degrees C the hydride-transfer rate of TmDHFR was 20 times lower than that observed for the E . coli enzyme at its physiological temperature . Hydride transfer depended on ionization of a single group in the active site with a p K(a) of 6.0 . While at 30 degrees C, turnover of substrate by TmDHFR was almost two orders of magnitude slower than by DHFR from E . coli; the steady-state rates of the two enzymes differed only 8-fold at their respective working temperatures. Biochemistry (Mosc), 2003 Apr, 68(4), 385 - 90 Ion transport coupled to terminal oxidase functioning in the extremely alkaliphilic halotolerant bacterium Thioalkalivibrio; Grischuk YV et al.; Proton transport in the terminal part of the respiratory chain in the extremely alkaliphilic halotolerant bacterial strain Thioalkalivibrio versutus was studied under near-optimum growth conditions (pH 9.0-9.5) . Under these conditions, bacterial cells generated electric potential with the negative charge being inside the cells . When only the terminal part of the respiratory chain functioned, it was found that: 1) unlike other bacteria known, this bacterium did not acidify the medium in the presence of K(+) and valinomycin; 2) in the presence of an uncoupler, CCCP, but in the absence of valinomycin, reversible alkalinization of the medium occurred as a result of proton influx into the cells . Cyanide prevented this alkalinization . The difference spectra indicate that cell membranes contained cytochromes c and (b+o), some of which reacted with CO . The respiratory activity of membranes in the terminal part of the respiratory chain was optimal at pH 9.5 and specifically depended on sodium ions (C(1/2) = 10 mM) . The data suggest the presence of a Na(+)-pump in the terminal part of the respiratory chain of the studied strain which can pump Na(+) out of the cells. Appl Microbiol Biotechnol, 2003 Sep, 62(4), 407 - 13 Epub 2003 May 23. Antifungal mechanism of an anti-Pythium protein (SAP) from the marine bacterium Streptomyces sp . strain AP77 is specific for Pythium porphyrae, a causative agent of red rot disease in Porphyra spp; Woo JH et al.; Previously we reported an antifungal protein specific to Pythium porphyrae, a causative agent of red rot disease afflicting seaweed Porphyra spp . This study was carried out to identify the antifungal mechanism of the antifungal protein to P . porphyrae . When we first examined the effect of an anti- Pythium protein (SAP) on the P . porphyrae cell walls, SAP did not decompose the six structural polysaccharides in Pythium cell walls . However, hyphal growth was significantly inhibited in Pythium cells treated with 50 microg/ml of SAP by MTT assay . Protoplasmic leakage was observed in P . porphyrae hyphae treated with SAP for 1 h, followed by hyphal swelling and disintegration, using SYTOX Green, and SAP permeabilized the membrane of P . porphyrae in a dose-dependent manner . Treating P . porphyrae cells with SAP in the presence of carbonyl cyanide m-chlorophenylhydrazone (CCCP), a membrane-depolarizing agent, significantly reduced the membrane permeability to SYTOX Green . Moreover, a similar effect was observed when the P . porphyrae cells were treated with SAP in the presence of MgCl2 . In contrast, identical treatment in the presence of KCl significantly increased the membrane permeability to SYTOX Green . These results suggested that anti- Pythium mechanism of SAP was related to alteration of the membrane permeability in P . porphyrae. J Biochem (Tokyo), 2003 Jan, 133(1), 51 - 8 Thermostable aspartase from a marine psychrophile, Cytophaga sp . KUC-1: molecular characterization and primary structure; Kazuoka T et al.; We found that a psychrophilic bacterium isolated from Antarctic seawater, Cytophaga sp . KUC-1, abundantly produces aspartase {EC4.3.1.1}, and the enzyme was purified to homogeneity . The molecular weight of the enzyme was estimated to be 192,000, and that of the subunit was determined to be 51,000: the enzyme is a homotetramer . L-Aspartate was the exclusive substrate . The optimum pH in the absence and presence of magnesium ions was determined to be pH 7.5 and 8.5, respectively . The enzyme was activated cooperatively by the presence of L-aspartate and by magnesium ions at neutral and alkaline pHs . In the deamination reaction, the K(m) value for L-aspartate was 1.09 mM at pH 7.0, and the S(1/2) value was 2.13 mM at pH 8.5 . The V(max) value were 99.2 U/mg at pH 7.0 and 326 U/mg at pH 8.5 . In the amination reaction, the K(m) values for fumarate and ammonium were 0.797 and 25.2 mM, respectively, and V(max) was 604 U/mg . The optimum temperature of the enzyme was 55 degrees C . The enzyme showed higher pH and thermal stabilities than that from mesophile: the enzyme was stable in the pH range of 4.5-10.5, and about 80% of its activity remained after incubation at 50 degrees C for 60 min . The gene encoding the enzyme was cloned into Escherichia coli, and its nucleotides were sequenced . The gene consisted of an open reading frame of 1,410-bp encoding a protein of 469 amino acid residues . The amino acid sequence of the enzyme showed a high degree of identity to those of other aspartases, although these enzymes show different thermostabilities. Infect Immun, 2003 Jun, 71(6), 3645 - 7 Involvement of nicotinic acetylcholine receptors in controlling Chlamydia pneumoniae growth in epithelial HEp-2 cells; Yamaguchi H et al.; Nicotinic acetylcholine receptors (nAChRs) play an essential role in neurotransmission . Recent studies have indicated that nAChRs may be involved in the regulation of some bacterial infections through immunological mechanisms in macrophages . However, the regulation of infection with Chlamydia pneumoniae, which is a ubiquitous pneumonia-causing bacterium, by an nAChR-mediated mechanism is still unclear . In the present study, it was found that stimulation of nAChRs with ligands such as nicotine and acetylcholine altered the growth of C . pneumoniae in epithelial HEp-2 cells . Thus, the results revealed a possible pathophysiological role of nAChRs in the regulation of intracellular bacterial infection. Infect Immun, 2003 Jun, 71(6), 3529 - 39 pH-regulated gene expression of the gastric pathogen Helicobacter pylori; Merrell DS et al.; Colonization by the gastric pathogen Helicobacter pylori has been shown to be intricately linked to the development of gastritis, ulcers, and gastric malignancy . Little is known about mechanisms employed by the bacterium that help it adapt to the hostile environment of the human stomach . In an effort to extend our knowledge of these mechanisms, we utilized spotted-DNA microarrays to characterize the response of H . pylori to low pH . Expression of approximately 7% of the bacterial genome was reproducibly altered by shift to low pH . Analysis of the differentially expressed genes led to the discovery that acid exposure leads to profound changes in motility of H . pylori, as a larger percentage of acid-exposed bacterial cells displayed motility and moved at significantly higher speeds . In contrast to previous publications, we found that expression of the bacterial virulence gene cagA was strongly repressed by acid exposure . Furthermore, this transcriptional repression was reflected at the level of protein accumulation in the H . pylori cell. Infect Immun, 2003 Jun, 71(6), 3010 - 9 A recombinant beta-1,3-glucanosyltransferase homolog of Coccidioides posadasii protects mice against coccidioidomycosis; Delgado N et al.; Coccidioides posadasii is a fungal respiratory pathogen which is responsible for recurrent epidemics of San Joaquin Valley fever (coccidioidomycosis) in desert regions of the southwestern United States . Numerous studies have revealed that the cell wall of the parasitic phase of the fungus is a reservoir of immunoreactive macromolecules and a potential source of a vaccine against this mycosis . A 495-bp fragment of a C . posadasii gene which encodes a putative wall-associated, glycosylphosphatidylinositol (GPI)-anchored beta-1,3-glucanosyltransferase was identified by computational analysis of the partially sequenced genome of this pathogen . The translated, full-length gene (GEL1) showed high sequence homology to a reported beta-1,3-glucanosyltransferase of Aspergillus fumigatus (70% identity, 90% similarity) and was selected for further study . The GEL1 mRNA of C . posadasii was detected at the highest level during the endosporulation stage of the parasitic cycle, and the mature protein was immunolocalized to the surface of endospores . BALB/c or C57BL/6 mice were immunized subcutaneously with the bacterium-expressed recombinant protein (rGel1p) to evaluate its protective efficacy against a lethal challenge of C . posadasii by either the intraperitoneal or intranasal route . In both cases, rGel1p-immune mice infected with the pathogen showed a significant reduction in fungal burden and increased survival compared to nonimmune mice . The recombinant beta-1,3-glucanosyltransferase is a valuable addition to an arsenal of immunoreactive proteins which could be incorporated into a human vaccine against coccidioidomycosis. Antimicrob Agents Chemother, 2003 Jun, 47(6), 1972 - 5 Chlamydia pneumoniae resists antibiotics in lymphocytes; Yamaguchi H et al.; Chlamydia pneumoniae infection of lymphocytes in blood has been well documented, and it is apparent that control of this pathogen in these cells may be critical in the development of chronic inflammatory diseases associated with infection by this bacterium . The activity of antibiotics against C . pneumoniae in lymphocytes was assessed in this study by utilizing an in vitro infection model with lymphoid cells . The results obtained indicated that although all of the antibiotics tested showed remarkable activity against bacterial growth in epithelial cells, C . pneumoniae in lymphocytes was less susceptible to antibiotics than was bacterial growth in epithelial cells, which are widely used for the evaluation of anti-C . pneumoniae antibiotics. Environ Microbiol, 2003 Jun, 5(6), 503 - 9 Marinobacterium sp . strain DMS-S1 uses dimethyl sulphide as a sulphur source after light-dependent transformation by excreted flavins; Hirano H et al.; Marinobacterium sp . strain DMS-S1 is a unique marine bacterium that can use dimethyl sulphide (DMS) as a sulphur source only in the presence of light . High-performance liquid chromatography (HPLC) analyses of the culture supernatant revealed that excreted factors, which could transform DMS to dimethyl sulphoxide (DMSO) under light, are FAD and riboflavin . In addition, FAD appeared to catalyse the photolysis of DMS to not only DMSO but also methanesulphonate (MSA), formate, formaldehyde and sulphate . As strain DMS-S1 can use sulphate and MSA as a sole sulphur source independently of light, the excretion of flavins appeared to support the growth on DMS under light . Furthermore, three out of 12 marine bacteria from IAM culture collection were found to be able to grow on DMS with the aid of photolysis by the flavins excreted . This is the first report that bacteria can use light to assimilate oceanic organic sulphur compounds outside the cells by excreting flavins as photosensitizers. Eur J Biochem, 2003 Jun, 270(11), 2476 - 85 Two W-containing formate dehydrogenases (CO2-reductases) involved in syntrophic propionate oxidation by Syntrophobacter fumaroxidans; de Bok FA et al.; Two formate dehydrogenases (CO2-reductases) (FDH-1 and FDH-2) were isolated from the syntrophic propionate-oxidizing bacterium Syntrophobacter fumaroxidans . Both enzymes were produced in axenic fumarate-grown cells as well as in cells which were grown syntrophically on propionate with Methanospirillum hungatei as the H2 and formate scavenger . The purified enzymes exhibited extremely high formate-oxidation and CO2-reduction rates, and low Km values for formate . For the enzyme designated FDH-1, a specific formate oxidation rate of 700 U.mg-1 and a Km for formate of 0.04 mm were measured when benzyl viologen was used as an artificial electron acceptor . The enzyme designated FDH-2 oxidized formate with a specific activity of 2700 U.mg-1 and a Km of 0.01 mm for formate with benzyl viologen as electron acceptor . The specific CO2-reduction (to formate) rates measured for FDH-1 and FDH-2, using dithionite-reduced methyl viologen as the electron donor, were 900 U.mg-1 and 89 U.mg-1, respectively . From gel filtration and polyacrylamide gel electrophoresis it was concluded that FDH-1 is composed of three subunits (89 +/- 3, 56 +/- 2 and 19 +/- 1 kDa) and has a native molecular mass of approximately 350 kDa . FDH-2 appeared to be a heterodimer composed of a 92 +/- 3 kDa and a 33 +/- 2 kDa subunit . Both enzymes contained tungsten and selenium, while molybdenum was not detected . EPR spectroscopy suggested that FDH-1 contains at least four {2Fe-2S} clusters per molecule and additionally paramagnetically coupled {4Fe-4S} clusters . FDH-2 contains at least two {4Fe-4S} clusters per molecule . As both enzymes are produced under all growth conditions tested, but with differences in levels, expression may depend on unknown parameters. Int J Med Microbiol, 2003 Apr, 293(1), 69 - 76 Mucosal immune response to Tropheryma whipplei; Ring S et al.; Whipple's disease is a rare infectious disease caused by the ubiquitously occurring Tropheryma whipplei in predisposed persons . Genetic or acquired defects in the mucosal and peripheral immune system become apparent as diminished Th1 immune functions with decreased production of IL-12 and IFN-gamma accompanied by an increased secretion of IL-4 . These defects may enable T . whipplei to survive and replicate . The recently established cultivation of the bacterium in HEL cells and the isolation from infected intestinal biopsies enable a multitude of experimental possibilities which may lead to an improved diagnosis as well as understanding of the etiology and pathogenesis of Whipple's disease. Prikl Biokhim Mikrobiol, 2003 May-Jun, 39(3), 322 - 8 {Growth of bacteria degrading naphthalene and salicylate at low temperatures}; Grishchenkov VG et al.; A total of 58 bacterial strains degrading naphthalene and salicylate were isolated from soil samples polluted with oil products, collected in different regions of Russia during winter and summer . The isolates were assessed for their ability to grow at low temperatures (4, 8, and 15 degrees C); bacteria growing at 4 degrees C in the presence of naphthalene or salicylate accounted for 65% and 53%, respectively, of the strains isolated . The strains differed in the temperature dependence of their growth rates . It was demonstrated that the type of expression of Nah+ phenotype at low temperatures depended on the combination of the host bacterium and the plasmid. J Bacteriol, 2003 Jun, 185(11), 3352 - 60 Genomic analysis and initial characterization of the chitinolytic system of Microbulbifer degradans strain 2-40; Howard MB et al.; The marine bacterium Microbulbifer degradans strain 2-40 produces at least 10 enzyme systems for degrading insoluble complex polysaccharides (ICP) . The draft sequence of the 2-40 genome allowed a genome-wide analysis of the chitinolytic system of strain 2-40 . The chitinolytic system includes three secreted chitin depolymerases (ChiA, ChiB, and ChiC), a secreted chitin-binding protein (CbpA), periplasmic chitooligosaccharide-modifying enzymes, putative sugar transporters, and a cluster of genes encoding cytoplasmic proteins involved in N-acetyl-D-glucosamine (GlcNAc) metabolism . Each chitin depolymerase was detected in culture supernatants of chitin-grown strain 2-40 and was active against chitin and glycol chitin . The chitin depolymerases also had a specific pattern of activity toward the chitin analogs 4-methylumbelliferyl-beta-D-N,N'-diacetylchitobioside (MUF-diNAG) and 4-methylumbelliferyl-beta-D-N,N',N"-triacetylchitotrioside (MUF-triNAG) . The depolymerases were modular in nature and contained glycosyl hydrolase family 18 domains, chitin-binding domains, and polycystic kidney disease domains . ChiA and ChiB each possessed polyserine linkers of up to 32 consecutive serine residues . In addition, ChiB and CbpA contained glutamic acid-rich domains . At 1,271 amino acids, ChiB is the largest bacterial chitinase reported to date . A chitodextrinase (CdxA) with activity against chitooligosaccharides (degree of polymerization of 5 to 7) was identified . The activities of two apparent periplasmic (HexA and HexB) N-acetyl-beta-D-glucosaminidases and one cytoplasmic (HexC) N-acetyl-beta-D-glucosaminidase were demonstrated . Genes involved in GlcNAc metabolism, similar to those of the Escherichia coli K-12 NAG utilization operon, were identified . NagA from strain 2-40, a GlcNAc deacetylase, was shown to complement a nagA mutation in E . coli K-12 . Except for the GlcNAc utilization cluster, genes for all other components of the chitinolytic system were dispersed throughout the genome . Further examination of this system may provide additional insight into the mechanisms by which marine bacteria degrade chitin and provide a basis for future research on the ICP-degrading systems of strain 2-40. J Bacteriol, 2003 Jun, 185(11), 3249 - 58 Inactivation of Mg chelatase during transition from anaerobic to aerobic growth in Rhodobacter capsulatus; Willows RD et al.; The facultative photosynthetic bacterium Rhodobacter capsulatus can adapt from an anaerobic photosynthetic mode of growth to aerobic heterotrophic metabolism . As this adaptation occurs, the cells must rapidly halt bacteriochlorophyll synthesis to prevent phototoxic tetrapyrroles from accumulating, while still allowing heme synthesis to continue . A likely control point is Mg chelatase, the enzyme that diverts protoporphyrin IX from heme biosynthesis toward the bacteriochlorophyll biosynthetic pathway by inserting Mg(2+) to form Mg-protoporphyrin IX . Mg chelatase is composed of three subunits that are encoded by the bchI, bchD, and bchH genes in R . capsulatus . We report that BchH is the rate-limiting component of Mg chelatase activity in cell extracts . BchH binds protoporphyrin IX, and BchH that has been expressed and purified from Escherichia coli is red in color due to the bound protoporphyrin IX . Recombinant BchH is rapidly inactivated by light in the presence of O(2), and the inactivation results in the formation of a covalent adduct between the protein and the bound protoporphyrin IX . When photosynthetically growing R . capsulatus cells are transferred to aerobic conditions, Mg chelatase is rapidly inactivated, and BchH is the component that is most rapidly inactivated in vivo when cells are exposed to aerobic conditions . The light- and O(2)-stimulated inactivation of BchH could account for the rapid inactivation of Mg chelatase in vivo and provide a mechanism for inhibiting the synthesis of bacteriochlorophyll during adaptation of photosynthetically grown cells to aerobic conditions while still allowing heme synthesis to occur for aerobic respiration. FEBS Lett, 2003 May 22, 543(1-3), 184 - 9 Plant polyphenols inhibit VacA, a toxin secreted by the gastric pathogen Helicobacter pylori; Tombola F et al.; VacA is a major virulence factor of the widespread stomach-dwelling bacterium Helicobacter pylori . It causes cell vacuolation and tissue damage by forming anion-selective, urea-permeable channels in plasma and endosomal membranes . We report that several flavone derivatives and other polyphenols present in vegetables and plants inhibit ion and urea conduction and cell vacuolation by VacA . Red wine and green tea, which contain many of the compounds in question, also potently inhibit the toxin . These observations suggest that polyphenols or polyphenol derivatives may be useful in the prevention or cure of H . pylori-associated gastric diseases. Oral Microbiol Immunol, 2003 Jun, 18(3), 135 - 9 Distribution of Actinobacillus actinomycetemcomitans serotypes and Porphyromonas gingivalis in Japanese adults; Yoshida Y et al.; Strains of the bacterium Actinobacillus actinomycetemcomitans found in the human oral cavity are divided into five serotypes, a, b, c, d, and e . In this study, A . actinomycetemcomitans serotypes and Porphyromonas gingivalis were isolated from 656 subgingival sites in systemically healthy Japanese adults . A . actinomycetemcomitans was detected in 19.5% of 328 Japanese subjects, while 27.1% of subjects were positive for P . gingivalis . Of 75 A . actinomycetemcomitans-positive sites, only one serotype was detected in 39 sites (52.0%) . The numbers of sites in which two different serotypes and three different serotypes were detected were 18 (25.0%) and 7 (9.3%), respectively . A . actinomycetemcomitans serotype c was detected more frequently in sites that were positive for both P . gingivalis and A . actinomycetemcomitans (76.9%) than in sites that were P . gingivalis-negative and A . actinomycetemcomitans-positive (33.9%) . In addition, serotype c was detected much more frequently than the other serotypes (<16%) in sites that were positive for both P . gingivalis and A . actinomycetemcomitans . These findings suggest that the characteristics of serotype c may differ from those of the other serotypes . This report is the first to use PCR to describe the distribution of A . actinomycetemcomitans serotypes in humans and to examine the association between the distribution of A . actinomycetemcomitans serotypes and the presence of P . gingivalis. J Periodontal Res, 2003 Jun, 38(3), 318 - 23 The herpesvirus-Porphyromonas gingivalis-periodontitis axis; Slots J et al.; OBJECTIVES AND BACKGROUND: Members of the herpesvirus family have accumulated considerable support for a role in severe types of periodontitis . This study aimed to examine whether human cytomegalovirus (HCMV), Epstein-Barr virus type 1 (EBV-1) or herpes simplex virus (HSV) together with the major periodontopathic bacterium Porphyromonas gingivalis might interact in the pathogenesis of periodontal breakdown . METHODS: Sixteen subjects each contributed paper point samples from two progressing and two stable periodontitis lesions, as determined by ongoing loss of probing attachment . Polymerase chain reaction methodology was used to identify subgingival herpesviruses, P . gingivalis and other bacterial pathogens . Chi-squared tests and multivariate logistic regression were employed to identify statistical associations between herpesviruses, periodontopathic bacteria and clinical variables . RESULTS: HCMV and HSV were both significant predictors of the presence of subgingival P . gingivalis . In turn, P . gingivalis was positively associated with periodontitis active disease, probing attachment level, probing pocket depth, gingival bleeding upon probing and patient age . EBV-1 was not linked to P . gingivalis, although the virus was predictive of periodontitis active disease . The periodontitis disease risk associated with herpesvirus-P . gingivalis combinations depended on both site-specific and subject-specific factors . CONCLUSION: The present data of aggressive periodontitis implicate HCMV, HSV and P . gingivalis as either cofactors in its etiology or triggers of relapses . Further studies are needed to determine the spectrum of periodontopathogenicity of herpesviruses and effective management of these viruses in periodontal sites. Eur J Biochem, 2003 May, 270(10), 2218 - 27 Accessory proteins functioning selectively and pleiotropically in the biosynthesis of {NiFe} hydrogenases in Thiocapsa roseopersicina; Maroti G et al.; There are at least two membrane-bound (HynSL and HupSL) and one soluble (HoxEFUYH) {NiFe} hydrogenases in Thiocapsa roseopersicina BBS, a purple sulfur photosynthetic bacterium . Genes coding for accessory proteins that participate in the biosynthesis and maturation of hydrogenases seem to be scattered along the chromosome . Transposon-based mutagenesis was used to locate the hydrogenase accessory genes . Molecular analysis of strains showing mutant phenotypes led to the identification of hupK (hoxV ), hypC1, hypC2, hypD, hypE, and hynD genes . The roles of hynD, hupK and the two hypC genes were investigated in detail . The putative HynD was found to be a hydrogenase-specific endoprotease type protein, participating in the maturation of the HynSL enzyme . HupK plays an important role in the formation of the functionally active membrane-bound {NiFe} hydrogenases, but not in the biosynthesis of the soluble enzyme . In-frame deletion mutagenesis showed that HypC proteins were not specific for the maturation of either hydrogenase enzyme . The lack of either HypC protein drastically reduced the activity of every hydrogenase . Hence both HypCs might participate in the maturation of {NiFe} hydrogenases . Homologous complementation with the appropriate genes substantiated the physiological roles of the corresponding gene products in the H2 metabolism of T . roseopersicina. Sao Paulo Med J, 2003 Jan 2, 121(1), 15 - 8 Epub 2003 Jul 04. Therapeutic efficacy of ranitidine bismuth citrate with clarithromycin for seven days in the eradication of Helicobacter pylori in Brazilian peptic ulcer patients; Eisig JN et al.; CONTEXT: The curative treatment of peptic ulcer is made available nowadays through the eradication of the bacterium Helicobacter pylori, which is associated with it, but the best therapeutic regimen is yet to be determined . OBJECTIVE: To assess the efficacy of a therapeutic regimen with 400 mg ranitidine bismuth citrate associated with 500 mg clarithromycin given twice a day for seven days in a cohort of Brazilian patients with peptic ulcer . TYPE OF STUDY: Cross-sectional study . SETTING: Tertiary-care hospital . PATIENTS: One hundred and twenty nine outpatients, with active or healed peptic ulcers infected by Helicobacter pylori, diagnosed via endoscopy with confirmation via the urease test and histological examination, who had never undergone a regimen for the eradication of the bacterium . PROCEDURE: Administration of 400 mg ranitidine-bismuth and 500 mg clarithromycin twice a day, for seven days . MAIN MEASUREMENTS: Efficacy of the treatment, with a check on the cure done via another endoscopy eight weeks after drug administration . The eradication of the bacterium was determined via the urease test and histological examination . Patients who were negative for both were considered to be cured . RESULTS: Eight patients failed to complete the study . The eradication rate according to intention to treat was 81% (104/129) and per protocol was 86% (104/121) . CONCLUSION: The bismuth ranitidine compound associated with clarithromycin used for one week was shown to be a simple, effective and well-tolerated therapeutic regimen for the eradication of Helicobacter pylori. DNA Seq, 2003 Feb, 14(1), 53 - 9 Isolation, sequencing, and characterization of the cytochrome bo operon from Vitreoscilla; Hwang KW et al.; The entire operon encoding the sodium pumping cytochrome bo from the bacterium Vitreoscilla was isolated and sequenced, and this sequence was analyzed by blast and hydropathy plots . There are fairly similar phylogenetic relationships which apply to all five proteins, but overall greater similarity to members of the gamma subdivision than the beta subdivision of the Proteobacteria . Hydropathy plots of all five Cyo proteins show near identity with those of the corresponding E . coli subunits, indicating that the similarity extends from sequence to structure . The operon appears to have a typical Shine-Dalgarno sequence, an E . coli-like promoter, and several possible binding sites for regulatory proteins . The Vitreoscilla Cyo B subunit (the probable Na+ pump) is almost identical to E . coli Cyo B at 18 key amino acids; thus, there are no obvious changes in Vitreoscilla Cyo B that hint at the details of its Na+ pumping ability. Genetics, 2003 May, 164(1), 5 - 12 Male-killing Wolbachia and mitochondrial DNA: selective sweeps, hybrid introgression and parasite population dynamics; Jiggins FM; Mitochondrial DNA (mtDNA) sequences are widely used as neutral genetic markers in insects . However, patterns of mtDNA variability are confounded by the spread of maternally transmitted parasites, which are genetically linked to the mitochondria . We have investigated these effects in the butterflies Acraea encedon (which is host to two strains of male-killing Wolbachia bacteria) and A . encedana (which is host to one strain) . Within a population, the mitochondria are in linkage disequilibrium with the different male-killers . Furthermore, there has been a recent selective sweep of the mtDNA, which has led to the loss of mitochondrial variation within populations and erased any geographical structure . We also found that one of the male-killers, together with the associated mtDNA, has introgressed from A . encedana into A . encedon within the last 16,000 years . Interestingly, because butterflies are female heterogametic, this will presumably have also led to the introgression of genes on the W sex chromosome . Finally, in A . encedon the mitochondria in uninfected females are unaltered by the spread of the male-killer and have diverse, geographically structured mtDNA . This means we can reject the hypothesis that the male-killer is at a stable equilibrium maintained by imperfect transmission of the bacterium . Instead, some other form of balancing selection may be maintaining uninfected females in the population and preventing the species from going extinct due to a shortage of males. Syst Appl Microbiol, 2003 Mar, 26(1), 3 - 12 Analysis of conserved non-rRNA genes of Tropheryma whipplei; Maiwald M et al.; The causative agent of Whipple's disease, Tropheryma whipplei, is a slow-growing bacterium that remains poorly-understood . Genetic characterization of this organism has relied heavily upon rRNA sequence analysis . Pending completion of a complete genome sequencing effort, we have characterized several conserved non-rRNA genes from T . whipplei directly from infected tissue using broad-range PCR and a genome-walking strategy . Our goals were to evaluate its phylogenetic relationships, and to find ways to expand the strain typing scheme, based on rDNA sequence comparisons . The genes coding for the ATP synthase beta subunit (atpD), elongation factor Tu (tuf), heat shock protein GroEL (groEL), beta subunit of DNA-dependent RNA polymerase (rpoB), and RNase P RNA (rnpB) were analyzed, as well as the regions upstream and downstream of the rRNA operon . Phylogenetic analyses with all non-rRNA marker molecules consistently placed T . whipplei within the class, Actinobacteria . The arrangement of genes in the atpD and rpoB chromosomal regions was also consistent with other actinomycete genomes . Tandem sequence repeats were found upstream and downstream of the rRNA operon, and downstream of the groEL gene . These chromosomal sites and the 16S-23S rRNA intergenic spacer regions were examined in the specimens of 11 patients, and a unique combination of tandem repeat numbers and spacer polymorphisms was found in each patient . These data provide the basis for a more discriminatory typing method for T . whipplei. Arch Biochem Biophys, 2003 Jun 1, 414(1), 51 - 8 Heterologous expression, purification, and enzymatic characterization of the acyclic carotenoid 1,2-hydratase from Rubrivivax gelatinosus; Steiger S et al.; The carotenoid 1,2-hydratase CrtC from Rubrivivax gelatinosus has been expressed in Escherichia coli in an active form and purified by affinity chromatography . The enzyme catalyzes the conversion of various acyclic carotenes including 1-hydroxy derivatives . This broad substrate specificity reflects the participation of CrtC in 1'-HO-spheroidene and in spirilloxanthin biosynthesis . Enzyme kinetic studies including the determination of substrate specificity constants indicate that among the alternative biosynthetic routes to 1'-HO-spheroidene the one via spheroidene is the dominating pathway . In contrast to CrtC from Rvi . gelatinosus, the equivalent enzyme from Rhodobacter capsulatus, a closely related bacterium which lacks the biosynthetic branch to spirilloxanthin and accumulates spheroidene instead of substantial amounts of 1'-HO-spheroidene, is extremely poor in converting 1-HO-carotenoids . The individual catalytic properties of both carotenoid 1,2-hydratases reflect the in situ carotenogenic pathways in both purple photosynthetic bacteria. Parasitol Res, 2003 May, 90(1), 38 - 47 Epub 2003 Jan 29. An aspartate aminotransferase of Wolbachia endobacteria from Onchocerca volvulus is recognized by IgG1 antibodies from residents of endemic areas; Fischer P et al.; Wolbachia are intracellular alpha-proteobacteria, closely related to Rickettsia, that infect various arthropods and filarial parasites . In the present study, the cDNA encoding the aspartate aminotransferase (AspAT) of Wolbachia from the human pathogenic filarial parasite Onchocerca volvulus (Ov-WolAspAT) was identified . At the amino acid level, the identity of the Ov-WolAspAT was 56% to Rickettsia prowazekii AspAT and 54% to the AspAT of the nitrogen-fixing bacterium Sinorhizobium meliloti, but the highest degree of identity was found to the putative AspAT of Wolbachia from Brugia malayi and Drosophila melanogaster (85%) . All of these bacterial AspATs are members of the AspAT subclass Ib . A 35 kDa fragment of the Ov-WolAspAT was expressed in Escherichia coli, and immunolocalization using polyclonal antibodies against this antigen revealed that Ov-WolAspAT is present in a considerable proportion of the Wolbachia from O . volvulus, as well as in the endobacteria of several other filarial parasites . Western blot analysis using recombinant Ov-WolAspAT as antigen showed that IgG1 antibodies were present in 70 (51%) individuals living in areas endemic for O . volvulus, B . malayi or Wuchereria bancrofti and no IgG4 or IgE antibodies were found . Among 40 sera of persons from Uganda and Liberia who were putatively not infected with human filarial parasites, 11 (28%) individuals presented IgG1 antibodies, while none of the 33 sera from healthy Europeans and none of the 14 sera from patients with proven Rickettsia or Brucella infections reacted with the antigen . These results also show that an intracellular protein of Wolbachia endobacteria (WolAspAT) acts as antigen in human filariasis. Transplant Proc, 2003 May, 35(3 Suppl), 227S - 230S Molecular actions of sirolimus: sirolimus and mTor; Kirken RA et al.; Recent therapeutic strategies to combat organ allograft rejection have focused on T-cell signaling pathways and the molecules that comprise them . The macrolide antibiotic produced by the bacterium Streptomyces hygroscopicus, known as sirolimus or rapamycin, has shown great therapeutic potential in the transplant setting . Sirolimus alone or in combination with other immunosuppressive agents can block acute rejection, chronic graft destruction, and promote permanent allograft acceptance . Sirolimus targets a unique serine-threonine kinase, mammalian target of rapamycin (mTor), which plays a key role in mitogenic and nutritional cells signals . Within T cells, mTor regulates a number of proteins likely dependent on T cell growth factors such as interleukin 2 . This review is focused on the molecular mechanisms by which mTor may regulate T-cell signaling cascades and affect T-cell responsiveness, and how sirolimus likely uncouples this activity. Biomacromolecules, 2003 May-Jun, 4(3), 850 - 5 Directed capture of enzymes and bacteria on bioplastic films; Koepsel RR et al.; The development of smart coatings for a variety of uses depends on the ability of the coating material to perform specific functions . We have used water dispersible polyurethane preparations for the immobilization of binding proteins under mild conditions . In these experiments, antibodies against the enzyme beta-galactosidase or the bacterium Escherichia coli were immobilized in polyurethane coatings and then used to effectively capture their cognate antigen . Further, a second, more general, capture protocol was developed which involves the incorporation of the protein avidin in the plastics . This system efficiently captures biotinylated beta-galactosidase . Biotinylated anti-E . coli antibody captured by avidin bioplastics resulted in a nearly 5-fold increase in the number of bound bacteria when compared to blank polyurethane . The use of avidin in a bioplastic allows any biotinylated antibody to be applied to all or part of the surface resulting in a patterning of capture agents on a preformed surface. Drugs Today (Barc), 2001 Nov, 37(11), 767 - 781 Esomeprazole: A significant advance beyond omeprazole in the treatment of acid-related disease; Rabasseda X et al.; The second-generation proton pump inhibitor (PPI) esomeprazole is a new chemical entity consisting of an optical isomer of omeprazole, which for many years has been acknowledged as the gold standard therapy in gastric acid-related disorders . Esomeprazole has demonstrated a unique pharmacokinetic profile and enhanced efficacy over omeprazole, with improved inter-patient pharmacokinetic consistency and a similar safety profile . Esomeprazole has been tested as a therapeutic agent in the management of erosive esophagitis, symptomatic gastroesophageal reflux disease (GERD) and, in combination with appropriate antibiotic therapy, for the eradication of the Helicobacter pylori bacterium and healing of H . pylori-associated duodenal ulcers . In clinical studies, esomeprazole has shown greater efficacy than omeprazole with a comparable low incidence of adverse events . (c) 2001 Prous Science . All rights reserved. FEMS Immunol Med Microbiol, 2003 May 25, 36(3), 127 - 34 Interactions of the gastrotropic bacterium Helicobacter pylori with the leukocyte-endothelium adhesion molecules, the selectins--a preliminary report; Galustian C et al.; The deleterious effects of Helicobacter pylori infection of the stomach are largely the result of a vigorous chronic inflammatory response, and include chronic gastritis, peptic ulceration and gastric cancer . We are exploring the possibility that carbohydrate components on H . pylori contribute to the persistent inflammation through interactions with leukocyte-endothelial adhesion molecules of the host . Lipopolysaccharides of most H . pylori strains contain sequences related to the Lewis (Le(x) or Le(a)) antigens . Carbohydrate sequences of this family encompass ligands for the leukocyte-endothelium adhesion molecules of the host, namely, the E- and P-selectins, which are expressed on inflamed endothelia, and L-selectin, which is constitutively expressed on leukocytes . Here we investigate H . pylori isolates from patients with chronic gastritis, duodenal ulcer and gastric cancer for their interactions with the selectins . Our results provide unequivocal evidence of interactions of isolates from each of the diagnostic groups with E- and L-selectins. Structure (Camb), 2003 May, 11(5), 547 - 55 The structure of Acidithiobacillus ferrooxidans c(4)-cytochrome: a model for complex-induced electron transfer tuning; Abergel C et al.; The study of electron transfer between the copper protein rusticyanin (RCy) and the c(4)-cytochrome CYC(41) of the acidophilic bacterium Acidithiobacillus ferrooxidans has evidenced a remarkable decrease of RCy's redox potential upon complex formation . The structure of the CYC(41) obtained at 2.2 A resolution highlighted a specific glutamate residue (E121) involved in zinc binding as potentially playing a central role in this effect, required for the electron transfer to occur . EPR and stopped-flow experiments confirmed the strong inhibitory effect of divalent cations on CYC(41):RCy complex formation . A docking analysis of the CYC(41) and RCy structure allows us to propose a detailed model for the complex-induced tuning of electron transfer in agreement with our experimental data, which could be representative of other copper proteins involved in electron transfer. Ear Nose Throat J, 2003 Apr, 82(4), 263 - 5 Tularemia of the head and neck: a possible sign of bioterrorism; Stupak HD et al.; Recent bioterror attacks and other world events have focused the medical community's attention on agents that might be used in biological warfare . One of these potential biological weapons is Francisella tularensis, a gramnegative coccobacillus that is one of the most infectious bacteria known . F tularensis can cause severe, even fatal, systemic tularemia . Under normal circumstances, F tularensis is transmitted by infected ticks, insects, and other animals . As a weapon of terrorism, the bacterium would likely be disseminated as an aerosol and contracted by inhalation . Because many cases of tularemia are characterized by head and neck symptoms, otolaryngologists should be familiar with the diagnosis and management of this disease . In this article, we describe a case of zoonotic tularemia that manifested as a neck mass, and we review the pathophysiology, diagnosis, and treatment of tularemia . We also summarize what is known about its potential as a biological weapon. J Clin Microbiol, 2003 May, 41(5), 1869 - 74 Evaluation of Coxiella burnetii antibiotic susceptibilities by real-time PCR assay; Brennan RE et al.; Coxiella burnetii is an obligate intracellular bacterium . The inability to cultivate this organism on axenic medium has made calculation of infectious units challenging and prevents the use of conventional antibiotic susceptibility assays . A rapid and reliable real-time PCR assay was developed to quantify C . burnetii cells from J774.16 mouse macrophage cells and was applied to antibiotic susceptibility testing of C . burnetii Nine Mile, phase I . For calculation of bacterial replication, real-time PCR performed equally as well as immunofluorescent-antibody (IFA) assay when J774.16 cells were infected with 10-fold serial dilutions of C . burnetii and was significantly (P < 0.05) more repeatable than IFA when 2-fold dilutions were used . Newly infected murine macrophage-like J774.16 cells were treated with 8 microg of chloramphenicol per ml, 4 microg of tetracycline per ml, 4 microg of rifampin per ml, 4 microg of ampicillin per ml, or 1 microg of ciprofloxacin per ml . After 6 days of treatment, tetracycline, rifampin, and ampicillin significantly (P < 0.01) inhibited the replication of C . burnetii, while chloramphenicol and ciprofloxacin did not . In general, these results are consistent with those from prior reports on the efficacy of these antibiotics against C . burnetii Nine Mile, phase I, and indicate that a real-time PCR-based assay is an appropriate alternative to the present methodology for evaluation of the antibiotic susceptibilities of C . burnetii. Genome Biol . 2003;4(5):213 . Epub 2003 Apr 28. Discovering human history from stomach bacteria; Disotell TR; Recent analyses of human pathogens have revealed that their evolutionary histories are congruent with the hypothesized pattern of ancient and modern human population migrations . Phylogenetic trees of strains of the bacterium Helicobacter pylori and the polyoma JC virus taken from geographically diverse groups of human beings correlate closely with relationships of the populations in which they are found. Curr Microbiol, 2003 May, 46(5), 329 - 33 Nitrite as an energy-conserving electron sink for the acetogenic bacterium Moorella thermoacetica; Seifritz C et al.; Nitrite served as an energy-conserving electron acceptor for the acetogenic bacterium Moorella thermoacetica . Growth occurred in an undefined (0.1% yeast extract) medium containing 20 m M glyoxylate and 5 m M nitrite and was essentially equivalent to that observed in the absence of nitrite . In the presence of nitrite, acetate (the normal product of glyoxylate-derived acetogenesis) was not detected during growth . Instead, growth was coupled to nitrite dissimilation to ammonium, and acetogenesis was limited to the stationary phase . Furthermore, membranes from glyoxylate-grown cells under nitrite-dissimilating conditions were deficient in the b-type cytochrome that is typically found in the membranes of acetogenic cells . Unlike glyoxylate, other acetogenic substrates (fructose, oxalate, glycolate, vanillin, and hydrogen) were not growth supportive in the undefined medium containing nitrite, and glyoxylate-dependent growth did not occur in a nitrite-supplemented, basal (without yeast extract) medium . Glyoxylate-dependent growth by Moorella thermoautotrophica was not observed in the undefined medium containing nitrite. J Biol Chem, 2003 Jul 18, 278(29), 27059 - 67 Epub 2003 May 05. Crystal structure of fungal lectin: six-bladed beta-propeller fold and novel fucose recognition mode for Aleuria aurantia lectin; Wimmerova M et al.; Aleuria aurantia lectin is a fungal protein composed of two identical 312-amino acid subunits that specifically recognizes fucosylated glycans . The crystal structure of the lectin complexed with fucose reveals that each monomer consists of a six-bladed beta-propeller fold and of a small antiparallel two-stranded beta-sheet that plays a role in dimerization . Five fucose residues were located in binding pockets between the adjacent propeller blades . Due to repeats in the amino acid sequence, there are strong similarities between the sites . Oxygen atoms O-3, O-4, and O-5 of fucose are involved in hydrogen bonds with side chains of amino acids conserved in all repeats, whereas O-1 and O-2 interact with a large number of water molecules . The nonpolar face of each fucose residue is stacked against the aromatic ring of a Trp or Tyr amino acid, and the methyl group is located in a highly hydrophobic pocket . Depending on the precise binding site geometry, the alpha- or beta-anomer of the fucose ligand is observed bound in the crystal . Surface plasmon resonance experiments conducted on a series of oligosaccharides confirm the broad specificity of the lectin, with a slight preference for alphaFuc1-2Gal disaccharide . This multivalent carbohydrate recognition fold is a new prototype of lectins that is proposed to be involved in the host recognition strategy of several pathogenic organisms including not only the fungi Aspergillus but also the phytopathogenic bacterium Ralstonia solanacearum. Appl Environ Microbiol, 2003 May, 69(5), 2906 - 13 Isolation and characterization of novel psychrophilic, neutrophilic, Fe-oxidizing, chemolithoautotrophic alpha- and gamma-proteobacteria from the deep sea; Edwards KJ et al.; We report the isolation and physiological characterization of novel, psychrophilic, iron-oxidizing bacteria (FeOB) from low-temperature weathering habitats in the vicinity of the Juan de Fuca deep-sea hydrothermal area . The FeOB were cultured from the surfaces of weathered rock and metalliferous sediments . They are capable of growth on a variety of natural and synthetic solid rock and mineral substrates, such as pyrite (FeS(2)), basalt glass ( approximately 10 wt% FeO), and siderite (FeCO(3)), as their sole energy source, as well as numerous aqueous Fe substrates . Growth temperature characteristics correspond to the in situ environmental conditions of sample origin; the FeOB grow optimally at 3 to 10 degrees C and at generation times ranging from 57 to 74 h . They are obligate chemolithoautotrophs and grow optimally under microaerobic conditions in the presence of an oxygen gradient or anaerobically in the presence of nitrate . None of the strains are capable of using any organic or alternate inorganic substrates tested . The bacteria are phylogenetically diverse and have no close Fe-oxidizing or autotrophic relatives represented in pure culture . One group of isolates are gamma-Proteobacteria most closely related to the heterotrophic bacterium Marinobacter aquaeolei (87 to 94% sequence similarity) . A second group of isolates are alpha-Proteobacteria most closely related to the deep-sea heterotrophic bacterium Hyphomonas jannaschiana (81 to 89% sequence similarity) . This study provides further evidence for the evolutionarily widespread capacity for Fe oxidation among bacteria and suggests that FeOB may play an unrecognized geomicrobiological role in rock weathering in the deep sea. Int J Hematol, 2003 Apr, 77(3), 239 - 44 Can eradication therapy for Helicobacter pylori really improve the thrombocytopenia in idiopathic thrombocytopenic purpura? Our experience and a literature review; Ando K et al.; Helicobacter pylori has recently been postulated to play a role in the pathogenesis of autoimmune diseases, including idiopathic thrombocytopenic purpura (ITP) . We investigated the prevalence of H pylori infection and the effects of its eradication in 61 patients with ITP . H pylori infection was found in 50 patients (83%), an incidence significantly higher than not only healthy volunteers in Japan (60%) but also subjects in other reported ITP series (approximately 43%-71%) . In our study, the mean age of H pylori-positive ITP patients (58.0 years) was significantly higher than that of H pylori-negative ITP patients (40.5 years) . Bacterium eradication efforts were performed in 29 infected ITP patients and succeeded in 27 patients (93%) . The 29 patients with eradicated H pylori infections showed significant increases in platelet counts compared with patients with uneradicated infections or who were H pylori-negative . During the follow-up period (median, 11.0 months), 16 (55%) of 29 patients achieved a major or a minor response . The patients who achieved a major response had not received previous prednisolone therapy, suggesting a relationship between prednisolone therapy and the response to eradication efforts . The assessment of H pylori infection and its eradication should be attempted in cases of ITP, because this approach may be a good new strategy for treating some ITP patients, especially elderly Japanese patients . Some regional factors have been suggested as causes of H pylori-associated ITP. J Bacteriol, 2003 May, 185(10), 3223 - 7 The single superoxide dismutase of Rhodobacter capsulatus is a cambialistic, manganese-containing enzyme; Tabares LC et al.; The phototrophic bacterium Rhodobacter capsulatus contains a single, oxygen-responsive superoxide dismutase (SOD(Rc)) homologous to iron-containing superoxide dismutase enzymes . Recombinant SOD(Rc), however, displayed higher activity after refolding with Mn(2+), especially when the pH of the assay mixture was raised . SOD(Rc) isolated from Rhodobacter cells also preferentially contains manganese, but metal discrimination depends on the culture conditions, with iron fractions increasing from 7% in aerobic cultures up to 40% in photosynthetic cultures . Therefore, SOD(Rc) behaves as a Mn-containing dismutase with cambialistic properties. J Bacteriol, 2003 May, 185(10), 3031 - 5 S-adenosylmethionine transport in Rickettsia prowazekii; Tucker AM et al.; Rickettsia prowazekii, the causative agent of epidemic typhus, is an obligate, intracellular, parasitic bacterium that grows within the cytoplasm of eucaryotic host cells . Rickettsiae exploit this intracellular environment by using transport systems for the compounds available in the host cell's cytoplasm . Analysis of the R . prowazekii Madrid E genome sequence revealed the presence of a mutation in the rickettsial metK gene, the gene encoding the enzyme responsible for the synthesis of S-adenosylmethionine (AdoMet) . Since AdoMet is required for rickettsial processes, the apparent inability of this strain to synthesize AdoMet suggested the presence of a rickettsial AdoMet transporter . We have confirmed the presence of an AdoMet transporter in the rickettsiae which, to our knowledge, is the first bacterial AdoMet transporter identified . The influx of AdoMet into rickettsiae was a saturable process with a K(T) of 2.3 micro M . Transport was inhibited by S-adenosylethionine and S-adenosylhomocysteine but not by sinfungin or methionine . Transport was also inhibited by 2,4-dinitrophenol, suggesting an energy-linked transport mechanism, and by N-ethylmaleimide . AdoMet transporters with similar properties were also identified in the Breinl strain of R . prowazekii and in Rickettsia typhi . By screening Escherichia coli clone banks for AdoMet transport, the R . prowazekii gene coding for a transporter, RP076 (sam), was identified . AdoMet transport in E . coli containing the R . prowazekii sam gene exhibited kinetics similar to that seen in rickettsiae . The existence of a rickettsial transporter for AdoMet raises intriguing questions concerning the evolutionary relationship between the synthesis and transport of this essential metabolite. Protein Expr Purif, 2003 May, 29(1), 33 - 41 An exotype alginate lyase in Sphingomonas sp . A1: overexpression in Escherichia coli, purification, and characterization of alginate lyase IV (A1-IV); Miyake O et al.; Sphingomonas sp . A1 (strain A1) cells contain three kinds of endotype alginate lyases {A1-I, A1-II, and A1-III}, all of which are formed from a common precursor through posttranslational processing . In addition to these lyases, another type of lyase (A1-IV) that acts on oligoalginates exists in the bacterium . A1-IV was overexpressed in Escherichia coli cells through control of its gene under the T7 promoter . The expression level of the enzyme in E . coli cells was 8.6U/L-culture, which was about 270-fold higher than that in strain A1 cells . The enzyme was purified to homogeneity through three steps with an activity yield of 10.9% . The optimal pH and temperature, thermal stability, and mode of action of the purified enzyme were similar to those of the native enzyme from strain A1 cells . A1-IV exolytically degraded oligo