J Bacteriol, 2000 Mar, 182(6), 1702 - 5 Dual roles of Bradyrhizobium japonicum nickelin protein in nickel storage and GTP-dependent Ni mobilization; Olson JW et al.; The hydrogenase accessory protein HypB, or nickelin, has two functions in the N(2)-fixing, H(2)-oxidizing bacterium Bradyrhizobium japonicum . One function of HypB involves the mobilization of nickel into hydrogenase . HypB also carries out a nickel storage/sequestering function in B . japonicum, binding nine nickel ions per monomer . Here we report that the two roles (nickel mobilization and storage) of HypB can be separated in vitro and in vivo using molecular and biochemical approaches . The role of HypB in hydrogenase maturation is completely dependent on its intrinsic GTPase activity; strains which produce a HypB protein that is severely deficient in GTPase activity but that fully retains nickel-sequestering ability cannot produce active hydrogenase even upon prolonged nickel supplementation . A HypB protein that lacks the nickel-binding polyhistidine region near the N terminus lacks only the nickel storage capacity function; it is still able to bind a single nickel ion and also retains complete GTPase activity. Biophys J, 2000 Mar, 78(3), 1570 - 7 Spectroscopy of individual light-harvesting 2 complexes of Rhodopseudomonas acidophila: diagonal disorder, intercomplex heterogeneity, spectral diffusion, and energy transfer in the B800 band; van Oijen AM et al.; This paper reports a detailed spectroscopic study of the B800 absorption band of individual light-harvesting 2 (LH2) complexes of the photosynthetic purple bacterium Rhodopseudomonas acidophila at 1 . 2 K . By applying single-molecule detection techniques to this system, details and properties can be revealed that remain obscured in conventional ensemble experiments . For instance, from fluorescence-excitation spectra of the individual complexes a more direct measure of the diagonal disorder could be obtained . Further spectral diffusion phenomena and homogeneous linewidths of individual bacteriochlorophyll a (BChl a) molecules are observed, revealing valuable information on excited-state dynamics . This work demonstrates that it is possible to obtain detailed spectral information on individual pigment-protein complexes, providing direct insight into their electronic structure and into the mechanisms underlying the highly efficient energy transfer processes in these systems. Infect Immun, 2000 Mar, 68(3), 1735 - 9 Bordetella pertussis virulence factors affect phagocytosis by human neutrophils; Weingart CL et al.; The interaction between human neutrophils and wild-type Bordetella pertussis or mutants expressing altered lipopolysaccharide or lacking virulence factors-pertussis toxin, adenylate cyclase toxin, dermonecrotic toxin, filamentous hemagglutinin (FHA), pertactin, or BrkA-was examined . In the absence of antibodies, the wild-type strain and the mutants, with the exception of mutants lacking FHA, attached efficiently to neutrophils . The addition of opsonizing antibodies caused a significant reduction (approximately 50%) in attachment of the wild-type strain and most of the mutants expressing FHA, suggesting that bacterium-mediated attachment is more efficient than Fc-mediated attachment . Phagocytosis was also examined . In the absence of antibodies, about 12% of the wild-type bacteria were phagocytosed . Opsonization caused a statistically significant reduction in phagocytosis (to 3%), possibly a consequence of reduced attachment . Phagocytosis of most of the mutants was similar to that of the wild type, with the exception of the mutants lacking adenylate cyclase toxin . About 70% of the adenylate cyclase toxin mutants were phagocytosed, but only in the presence of opsonizing antibody, suggesting that Fc receptor-mediated signaling may be needed for phagocytosis . These studies indicate that FHA mediates attachment of B . pertussis to neutrophils, but adenylate cyclase toxin blocks phagocytosis. Infect Immun, 2000 Mar, 68(3), 1480 - 4 Influence of the bcg locus on natural resistance to primary infection with the facultative intracellular bacterium Francisella tularensis in mice; Kovarova H et al.; The implication of the Bcg locus in the control of natural resistance to infection with a live vaccine strain (LVS) of the intracellular pathogen Francisella tularensis was studied . Analysis of phenotypic expression of natural resistance and susceptibility was performed using mouse strains congenic at the Bcg locus . Comparison of the kinetics of bacterial colonization of spleen showed that B10.A.Bcg(r) mice were extremely susceptible during early phases of primary sublethal infection, while their congenic C57BL/10N {Bcg(s)} counterparts could be classified as resistant to F . tularensis LVS infection according to the 2-log-lower bacterial CFU within the tissue as long as 5 days after infection . Different phenotypes of Bcg congenic mice were associated with differential expression of the cytokines tumor necrosis factor alpha, interleukin-10, and gamma interferon and production of reactive oxygen intermediates . These results strongly suggest that the Bcg locus, which is close or identical to the Nramp1 gene, controls natural resistance to infection by F . tularensis and that its effect is the opposite of that observed for other Bcg-controlled pathogens. Infect Immun, 2000 Mar, 68(3), 1441 - 9 Characterization of Porphyromonas gingivalis-induced degradation of epithelial cell junctional complexes; Katz J et al.; Porphyromonas gingivalis is considered among the etiological agents of human adult periodontitis . Although in vitro studies have shown that P . gingivalis has the ability to invade epithelial cell lines, its effect on the epithelial barrier junctions is not known . Immunofluorescence analysis of human gingival epithelial cells confirmed the presence of tight-junction (occludin), adherens junction (E-cadherin), and cell-extracellular matrix junction (beta1-integrin) transmembrane proteins . These transmembrane proteins are expressed in Madin-Darby canine kidney (MDCK) cells . In addition, MDCK cells polarize and therefore serve as a useful in vitro model for studies on the epithelial cell barrier . Using the MDCK cell system, we examined the effect of P . gingivalis on epithelial barrier function . Exposure of the basolateral surfaces of MDCK cells to P . gingivalis (>10(9) bacteria/ml) resulted in a decrease in transepithelial resistance . Immunofluorescence microscopy demonstrated decreases in the amounts of immunoreactive occludin, E-cadherin, and beta1-integrin at specific times which were related to a disruption of cell-cell junctions in MDCK cells exposed to basolateral P . gingivalis . Disruption of cell-cell junctions was also observed upon apical exposure to bacteria; however, the effects took longer than those seen upon basolateral exposure . Cell viability was not affected by either basolateral or apical exposure to P . gingivalis . Western blot analysis demonstrated hydrolysis of occludin, E-cadherin, and beta1-integrin in lysates derived from MDCK cells exposed to P . gingivalis . Immunoprecipitated occludin and E-cadherin molecules from MDCK cell lysates were also degraded by P . gingivalis, suggesting a bacterial protease(s) capable of cleaving these epithelial junction transmembrane proteins . Collectively, these data suggest that P . gingivalis is able to invade the deeper structures of connective tissues via a paracellular pathway by degrading epithelial cell-cell junction complexes, thus allowing the spread of the bacterium . These results also indicate the importance of a critical threshold concentration of P . gingivalis to initiate epithelial barrier destruction. Infect Immun, 2000 Mar, 68(3), 1391 - 9 Role of decay-accelerating factor domains and anchorage in internalization of Dr-fimbriated Escherichia coli; Selvarangan R et al.; Dr-fimbriated Escherichia coli capable of invading epithelial cells recognizes human decay-accelerating factor (DAF) as its cellular receptor . The role of extracellular domains and the glycosylphosphatidylinositol anchor of DAF in the process of internalization of Dr(+) E . coli was characterized in a cell-cell interaction model . Binding of Dr(+) E . coli to the short consensus repeat 3 domain of DAF expressed by Chinese hamster ovary cells was critical for internalization to occur . Deletion of short consensus repeat 3 domain or replacement of Ser(165) by Leu in this domain, or the use of a monoclonal antibody to this region abolished internalization . Replacing the glycosylphosphatidylinositol anchor of DAF with the transmembrane anchor of membrane cofactor protein or HLA-B44 resulted in abolition or reduction of internalization respectively . Cells expressing glycosylphosphatidylinositol-anchored DAF but not the transmembrane-anchored DAF internalized Dr(+) E . coli through a glycolipid pathway, since the former cells were more sensitive to inhibition by methyl-beta-cyclodextrin, a sterol-chelating agent . Electron microscopic studies revealed that the intracellular vacuoles containing the internalized Dr(+) E . coli were morphologically distinct between the anchor variants of DAF . The cells expressing glycosylphosphatidylinositol-anchored DAF contained a single bacterium in tight-fitting vacuoles, while the cells expressing transmembrane-anchored DAF contained multiple (two or three) bacteria in spacious phagosomes . This finding suggests that distinct postendocytic events operate in the cells expressing anchor variants of DAF . We provide direct evidence for the DAF-mediated internalization of Dr(+) E . coli and demonstrate the significance of the glycosylphosphatidylinositol anchor, which determines the ability and efficiency of the internalization event. Clin Ter, 1999 Sep-Oct, 150(5), 343 - 6 {The effects of eradication therapy in patients with chronic atrophic gastritis and seropositivity for anti-HP antibodies and histological negativity for Helicobacter pylori}; Leri O et al.; PURPOSE: The present study was undertaken to analyze both whether the elevated Helicobacter pylori levels in patients with atrophic gastritis without histologic evidence of Helicobacter pylori would be a sign of an ongoing infection and the effects of eradication on gastric atrophy . PATIENTS AND METHODS: Twenty patients (10 M e 10 F; mean age 57.25 SD 12.19) with atrophic gastritis and elevated Helicobacter pylori titers without histological evidence for Helicobacter-like organisms were included in the study . Ten patients were randomized into eradication group (Group 1) (amoxicillin at 500 mg twice a day for 14 days, metronidazole at 500 mg twice a day for 10 days and omeprazole at 20 mg twice a day for 20 days) and 10 patients were randomized into the control group (Group 2) . For all subjects, serum samples and duplicate biopsy specimens (obtained endoscopically) were collected prior the study period and approximately 6 months after the therapy or the follow-up for serum samples and 8 weeks for biopsy specimens . RESULTS: In the Group 1, the Helicobacter pylori antibody titers dropped significantly in 73.39% of the patients (p < 0.0001), while in the Group 2, the antibody titers declined only in a patient who received antibiotics during the study period (p < 0.00006) . In both groups, no significant improvement of atrophic gastritis was observed . CONCLUSIONS: In conclusion, in patients with atrophic gastritis, the only histological evaluation of Helicobacter-like organisms colonization in gastric biopsy specimens, appeared in our study to underestimate the true prevalence of current HP infection and the importance of the bacterium in the pathogenesis and progression of such disease . Since HP infection is often associated with an increase of proliferative index, the eradication of HP could induce a mucosal protective effect against the other carcinogen factors, although it is extremely unlikely that it can promote the regeneration of a normal gastric mucosa. Genetika, 1999 Dec, 35(12), 1718 - 20 {Spontaneous mutants of Alteromonas espejiana, resistant to kanamycin and bleomycin}; Gonikberg EM et al.; An attempt was made to induce insertions in marine bacterium Alteromonas espejiana Bal-31 (Ae) using the TnphoA transposon . The Ae mutants selected on a kanamycin-containing medium after conjugation of the Ae with the transposon donor, Escherichia coli SM10(pRt291), were resistant not only to kanamycin (Kn), but also to bleomycin (Bm), and were sensitive to tetracycline . Although the mutants were phenotypically similar to insertion mutants, the mutations appeared to be spontaneous . The sensitivity of spontaneous Kmr Ae mutants selected at various Km concentrations to Bm was investigated . The mutants selected at low Km concentrations were resistant to Bm, whereas those selected at high Km concentrations were sensitive to Bm . The possible mechanisms underlying the dual resistance to Bm and aminoglycosides in bacteria are discussed. J Mol Biol, 2000 Mar 3, 296(4), 969 - 77 Antirestriction protein Ard (Type C) encoded by IncW plasmid pSa has a high similarity to the "protein transport" domain of TraC1 primase of promiscuous plasmid RP4; Belogurov AA et al.; The IncW plasmid pSa contains the gene ard encoding an antirestriction function that is specific for type I restriction and modification systems . The nucleotide sequence of ard was determined and an appropriate polypeptide of about 33 kDa was identified in Escherichia coli T7 expression system . Analysis of deduced amino acid sequence of Ard encoded by pSa revealed that this protein has no significant similarities with the known Ard proteins (ArdA and ArdB types) except the "antirestriction" motif (14 amino acid residues in length) conserved for all known Ard proteins . This finding suggests that pSa Ard may be classified as a new type of Ard proteins which we designated ArdC . The remarkable feature of ArdC is that it has a high degree of similarity (about 38 % identity) to the N-terminal region of RP4 TraC1 primase which includes about 300 amino acid residues and seems to be essential for binding to the single-stranded DNA and TraC1 protein transport to the recipient cells during the conjugal transfer of plasmid DNA . ArdC also binds to single-stranded DNA . In addition, this protein is able in vitro to protect the single-stranded but not double-stranded plasmid DNA against the activity of type II restriction endonuclease HhaI that cleaves both single and double-stranded DNA . We suggest that like TraC1, ArdC would be transported as a result of their interaction with the single-stranded DNA of transferred plasmid strand during conjugative passage through the cell envelope to the recipient bacterium . Such properties of ArdC protein might be useful to protect immediately the incoming single-stranded DNA from the host endonucleases . J Periodontal Res, 1999 Oct, 34(7), 400 - 5 The rag locus of Porphyromonas gingivalis: a novel pathogenicity island; Curtis MA et al.; Previous studies in our laboratories of the serum IgG antibody response of periodontal patients have demonstrated the presence of an immunodominant surface antigen (Mr 55 kDa) in the outer membrane of Porphyromonas gingivalis W50 . Genetic analysis of this antigen revealed that the corresponding gene forms part of a small operon which may have arisen via horizontal gene transfer into the genome of this strain . On the basis of sequence homology, the 55 kDa antigen (RagB) and the product of a cotranscribed gene (RagA) may act in concert at the surface of the bacterium to facilitate active transport, mediated through the periplasmic spanning protein, TonB, or form part of a signal transduction system in this organism . The rag locus is present in only a proportion of P . gingivalis laboratory strains and clinical isolates . Analysis of the distribution of ragB in subgingival samples by PCR demonstrated that rag+ P . gingivalis are more frequently detected in deep periodontal pockets than shallow sites in periodontal patients . These findings indicate that the rag genes may influence the virulence potential of P . gingivalis strains which harbour this locus and may thus be considered a novel pathogenicity island . Furthermore, horizontal gene transfer between organisms in subgingival plaque may represent a significant force in the evolution of these bacteria with ramifications for both diagnosis and targeted treatment of periodontal disease. Res Vet Sci, 2000 Feb, 68(1), 23 - 6 Detection of Lawsonia intracellularis in the tonsils of pigs with proliferative enteropathy; Jensen TK et al.; The presence of Lawsonia intracellularis, the obligate intracellular bacterium causing proliferative enteropathy (PE), in the tonsils of pigs as a locus for infection or extraintestinal occurrence of the bacterium was investigated by PCR and immunohistochemistry . Tonsillar occurrence of L . intracellularis could be part of the pathogenesis of PE and an important risk factor in the spread of the disease . L . intracellularis was detected by only PCR in the tonsils of 2/32 pigs without PE at necropsy but with a clinical history of diarrhoea and detection of the bacterium in faeces 1 to 3 weeks prior to necropsy but not in four pigs with moderate PE lesions . However, L . intracellularis was detected in the tonsils of 4/9 pigs with PE complicated with necroses and in 4/4 pigs with proliferative haemorrhagic enteropathy in which L . intracellularis antigen also was demonstrated in tonsillar macrophages and as intact bacteria in the lumen of the crypts . The results show that L . intracellularis is detectable in the tonsils of pigs and that the tonsillar presence of L . intracellularis appears to be correlated to the severity of the intestinal lesions possibly as a result of local retention and not as part of the pathogenesis of PE . Nucleic Acids Res, 2000 Mar 15, 28(6), 1447 - 54 Ligation reaction specificities of an NAD(+)-dependent DNA ligase from the hyperthermophile Aquifex aeolicus; Tong J et al.; An NAD(+)-dependent DNA ligase from the hyperthermophilic bacterium Aquifex aeolicus was cloned, expressed in Escherichia coli and purified to homogeneity . The enzyme is most active in slightly alkaline pH conditions with either Mg(2+)or Mn(2+)as the metal cofactor . Ca(2+)and Ni(2+)mainly support formation of DNA-adenylate intermediates . The catalytic cycle is characterized by a low k (cat)value of 2 min(-1)with concomitant accumulation of the DNA - adenylate intermediate when Mg(2+)is used as the metal cofactor . The ligation rates of matched substrates vary by up to 4-fold, but exhibit a general trend of T/A < or = G/C < C/G < A/T on both the 3'- and 5'-side of the nick . Consistent with previous studies on Thermus ligases, this Aquifex ligase exhibits greater discrimination against a mismatched base pair on the 3'-side of the nick junction . The requirement of 3' complementarity for a ligation reaction is reaffirmed by results from 1 nt insertions on either the 3'- or 5'-side of the nick . Furthermore, most of the unligatable 3' mismatched base pairs prohibit formation of the DNA-adenylate intermediate, indicating that the substrate adenylation step is also a control point for ligation fidelity . Unlike previously studied ATP ligases, gapped substrates cannot be ligated and intermediate accumulation is minimal, suggesting that complete elimination of base pair complementarity on one side of the nick affects substrate adenylation on the 5'-side of the nick junction . Relationships among metal cofactors, ligation products and intermediate, and ligation fidelity are discussed. FEMS Immunol Med Microbiol, 2000 Mar, 27(3), 241 - 6 Isolation and characterization of a human neutrophil aggregation defective mutant of Fusobacterium nucleatum; Guo M et al.; Fusobacterium nucleatum is known to adhere to human polymorphonuclear neutrophils (PMNs) and cause them to aggregate . In this study, we isolated a spontaneously occurring aggregation defective (AGG(-)) mutant and this mutant will be used for future study of the interactions between this bacterium and human PMN . Genomic DNA fingerprinting by random-primed polymerase chain reaction method revealed a difference between the parent strain and the AGG(-) mutant . This mutant also showed an altered phenotype in both microbicidal and phagocytic assays, suggesting that the bacterial factor involved in the aggregation may also be very important for the phagocytosis and, subsequently, the killing by human PMNs . Further study of this mutant may help to clarify the molecular mechanisms of the interaction between this pathogen and human PMNs. J Biotechnol, 2000 Feb 17, 77(2-3), 219 - 34 Engineering of a proteolytically stable human beta 2-adrenergic receptor/maltose-binding protein fusion and production of the chimeric protein in Escherichia coli and baculovirus-infected insect cells; Hampe W et al.; The hydrophobic human beta 2 adrenergic receptor was produced in fusion to the hydrophilic maltose-binding protein (MalE) in Escherichia coli . Photoaffinity labeling with the adrenergic ligand {125I}cyanopindolole-diazirine indicated that the majority of the protein was proteolyzed in the intergenic region between the fusion partners after production in E . coli . The simple and fast genetics of the bacterium enabled us to engineer a linker with an increased proteolytic stability . The fusion protein produced in E . coli was fully functional with respect to binding of adrenergic ligands and coupling to stimulatory GTP-binding protein . The production level with 3 pmol receptor fusion protein per mg membrane protein in a crude membrane preparation was significantly higher than those reported for other beta 2 adrenergic receptor constructs in E . coli . After solubilization with dodecanoyl sucrose, the fusion protein was purified to near homogeneity by affinity chromatography on immobilized Ni2+ ions (binding to a C-terminal His6-tag) and on crosslinked amylose (binding to the MalE) . In order to achieve higher production levels, the fusion protein preceded by an insect signal peptide was produced in baculovirus-infected insect cells . As expected, the production level with about 17 pmol receptor per mg membrane protein was higher in the insect cells than in E . coli . The receptor fusion protein produced in the insect cells bound adrenergic ligands and activated heterotrimeric GTP-binding proteins with biochemical properties comparable to that of the unfused receptor. Biochem Biophys Res Commun, 2000 Feb 16, 268(2), 302 - 5 Deficiency of current methods in assaying endochitinase activity; Ren Y et al.; Since chitin is degraded by a combination of both endo- and exochitinases, it is likely that both enzymes will be present in a crude extract . Currently used substrates for detecting endochitinase activity suffer from the fact that they could easily be digested by the contaminating exochitinase, thus giving either a false-positive or an inaccurate reading of the endochitinase activity . Using Photorhabdus luminescens, a bacterium symbiotically associated with insect-parasitic nematode Heterorhabditis bacteriophora as an exemplary system, we have identified these two chitinases by a simple "fluorimetric zymography" procedure . The exochitinase is a metalloenzyme and its activity is inhibited by 1,10-phenanthroline . Once the exochitinase activity is detected in a crude extract, its contribution must be eliminated before accurate determination of the endochitinase activity can be carried out . Specific properties of these enzymes including the pH activity profile, the requirement of metal ions for activity, and the molecular weight of the enzymes are among the factors to be considered in developing assaying procedures for endochitinase . J Chromatogr B Biomed Sci Appl, 2000 Jan 14, 737(1-2), 245 - 51 Pullulanase from the hyperthermophilic bacterium Thermotoga maritima: purification by beta-cyclodextrin affinity chromatography; Kriegshauser G et al.; This is the first report about the isolation of a type I pullulanase from a hyperthermophilic bacterium, Thermotoga maritima strain MSB8 . Purification of the enzyme from a cleared cell-free extract was achieved by anion-exchange chromatography and beta-cyclodextrin affinity chromatography . Using this convenient two-step method we have purified the pullulanase 406-fold with a 26% yield . The purified enzyme displayed maximum pullulan hydrolysis at pH 5.9 and 90 degrees C (15-min assay) and was remarkably resistant against thermoinactivation, having a half-life at 90 degrees C of about 3.5 h . To our knowledge, the T . maritima pullulanase is the most thermostable type I pullulanase known to date . The affinity-based purification protocol described here may be useful for the efficient isolation of other pullulanases. Ann Surg, 2000 Feb, 231(2), 153 - 8 Eradication of Helicobacter pylori prevents recurrence of ulcer after simple closure of duodenal ulcer perforation: randomized controlled trial; Ng EK et al.; OBJECTIVE: In this randomized trial, the authors sought to determine whether eradication of Helicobacter pylori could reduce the risk of ulcer recurrence after simple closure of perforated duodenal ulcer . BACKGROUND DATA: Immediate acid-reduction surgery has been strongly advocated for perforated duodenal ulcers because of the high incidence of ulcer relapse after simple patch repair . Although H . pylori eradication is now the standard treatment of uncomplicated and bleeding peptic ulcers, its role in perforation remains controversial . Recently a high prevalence of H . pylori infection has been reported in patients with perforations of duodenal ulcer . It is unclear whether eradication of the bacterium confers prolonged ulcer remission after simple repair and hence obviates the need for an immediate definitive operation . METHODS: Of 129 patients with perforated duodenal ulcers, 104 (81%) were shown to be infected by H . pylori . Ninety-nine H . pylori-positive patients were randomized to receive either a course of quadruple anti-helicobacter therapy or a 4-week course of omeprazole alone . Follow-up endoscopy was performed 8 weeks, 16 weeks (if the ulcer did not heal at 8 weeks), and 1 year after hospital discharge for surveillance of ulcer healing and determination of H . pylori status . The endpoints were initial ulcer healing and ulcer relapse rate after 1 year . RESULTS: Fifty-one patients were assigned to the anti-Helicobacter therapy and 48 to omeprazole alone . Nine patients did not undergo the first follow-up endoscopy . Of the 90 patients who did undergo follow-up endoscopy, 43 of the 44 patients in the anti-Helicobacter group and 8 of the 46 in the omeprazole alone group had H . pylori eradicated; initial ulcer healing rates were similar in the two groups (82% vs . 87%) . After 1 year, ulcer relapse was significantly less common in patients treated with anti-Helicobacter therapy than in those who received omeprazole alone (4.8% vs . 38.1%) . CONCLUSIONS: Eradication of H . pylori prevents ulcer recurrence in patients with H . pylori-associated perforated duodenal ulcers . Immediate acid-reduction surgery in the presence of generalized peritonitis is unnecessary. Biochim Biophys Acta, 1999 Dec 23, 1489(2-3), 281 - 92 Characterization of the Azoarcus ribozyme: tight binding to guanosine and substrate by an unusually small group I ribozyme; Kuo LY et al.; We report novel chemical properties of the ribozyme derived from the smallest group I intron (subgroup IC3) that comes from the pre-tRNA(Ile) of the bacterium Azoarcus sp . BH72 . Despite the small size of the Azoarcus ribozyme (195 nucleotides (nt)), it binds tightly to the guanosine nucleophile (Kd = 15 +/- 3 microM) and exhibits activity at high temperatures (approximately 60-70 degrees C) . These features may be due to the two GA3 tetraloop interactions postulated in the intron and the high GC content of the secondary structure . The second order rate constant for the Azoarcus ribozyme, ((k(cat)/Km)S = 8.4 +/- 2.1 x 10(-5) M(-1) min(-1)) is close to that found for the related ribozyme derived from the pre-tRNA(Ile) of the cyanobacterium Anabaena PCC7120 . pH dependence studies and kinetic analyses of deoxy-substituted substrates suggest that the chemical cleavage step is the rate-determining process in the Azoarcus ribozyme . This may be due to the short 3-nt guide sequence-substrate pairing present in the Azoarcus ribozyme . Finally, the Azoarcus ribozyme shares features conserved in other group I ribozymes including the pH profile, the stereospecificity for the Rp-phosphorothioate at the cleavage site and the 1000-fold decrease in cleavage rate with a deoxyribonucleoside leaving group. Res Microbiol, 1999 Nov-Dec, 150(9-10), 711 - 24 Short repeats and IS elements in the extremely radiation-resistant bacterium Deinococcus radiodurans and comparison to other bacterial species; Makarova KS et al.; Computer analysis of the complete genome of Deinococcus radiodurans R1 has shown that the number of insertion sequences (ISs) and small noncoding repeats (SNRs) it contains is very high, and comparable with those of Escherichia coli . IS elements and several families of SNRs are described, together with their possible function in the D . radiodurans genome. Helicobacter, 2000 Mar, 5(1), 1 - 12 Analysis of iceA1 transcription in Helicobacter pylori; Donahue JP et al.; BACKGROUND: Transcription of the Helicobacter pylori iceA1 gene is induced following adherence of the bacterium to gastric epithelial cells in vitro, suggesting that this gene might be involved in H . pylori pathogenesis . Consequently, the current studies were undertaken to characterize iceA1 transcription and to define the structure of iceA1-containing transcripts to evaluate the potential of this gene to encode functional proteins . MATERIALS AND METHODS: Northern blots and primer extension of RNA isolated from broth-grown cultures of various H . pylori strains was done to analyze iceA1-specific gene transcription . Reverse transcriptase (RT)-PCR was used to determine the levels of iceA1 transcripts derived from readthrough transcription that was initiated upstream of iceA1 within the 5'-flanking cysE gene . RESULTS: Three major transcripts were detected and each was initiated from a common promoter, designated PI . Two of these transcripts were comprised of iceA1 sequence, while a third transcript was dicistronic and included the downstream gene, hpyIM . In addition, 10-fold lower levels of iceA1 transcripts were initiated upstream of PI, either within or immediately downstream of cysE . CONCLUSIONS: The present analysis suggests that iceA1 does not encode a functional protein in the majority of H . pylori strains . However, transcription of hpyIM, which encodes a highly conserved DNA adenine methyltransferase, is linked to iceA1 transcription . Therefore, iceA1 may affect H . pylori virulence in vivo through transcriptional regulation of hpyIM expression levels, which may result in specific variations in DNA methylation patterns leading to alteration in the expression of genes involved in virulence or pathogenesis. J Biol Chem, 2000 Feb 18, 275(7), 4679 - 86 Regulation of cytochrome bd expression in the obligate aerobe Azotobacter vinelandii by CydR (Fnr) . Sensitivity to oxygen, reactive oxygen species, and nitric oxide; Wu G et al.; Azotobacter vinelandii is an obligately aerobic bacterium in which aerotolerant nitrogen fixation requires cytochrome bd . Regulation of cytochrome bd expression is achieved by CydR (an Fnr homologue), which represses transcription of the oxidase genes cydAB . cydAB mRNA was mapped by primer extension; the transcriptional start site was determined, and putative -10 and -35 regions were deduced . Two "CydR boxes," one at the +1 site and one upstream of the -35 region, were identified . Transcriptionally inactive, purified CydR was converted, by adding NifS, cysteine, and Fe(2+), into an active form possessing acid-labile sulfide and spectra suggesting a {4Fe-4S}(2+) cluster . Reconstituted CydR specifically bound both CydR boxes cooperatively, with higher affinity for the nearer consensus +1 site . Low concentrations of O(2) or NO ({O(2)}/{{CydR} or {NO}/{CydR} = 0.1-0 . 6) elicited loss of the 420 nm absorbance attributed to the {4Fe-4S}(2+) cluster, formation of a 315 nm species, and loss of ability to retard DNA migration . Retardation by reconstituted CydR was enhanced by superoxide dismutase and/or catalase, suggesting a role for reactive oxygen species in CydR inactivation . The role of CydR in regulating cydAB expression in the supposedly anoxic cytoplasm of A . vinelandii and similarities to cydAB regulation by Fnr in Escherichia coli are discussed. J Bacteriol, 2000 Mar, 182(5), 1442 - 7 Cytochrome c' from Rhodobacter capsulatus confers increased resistance to nitric oxide; Cross R et al.; We report the cloning and sequencing of the gene containing cytochrome c' (cycP) from the photosynthetic purple bacterium Rhodobacter capsulatus and the regions flanking that gene . Mutant strains unable to synthesize cytochrome c' had increased sensitivity to nitrosothiols and to nitric oxide (which binds to the heme moiety of cytochrome c'). J Bacteriol, 2000 Mar, 182(5), 1208 - 14 Enhanced nitrogenase activity in strains of Rhodobacter capsulatus that overexpress the rnf genes; Jeong HS et al.; In the photosynthetic bacterium Rhodobacter capsulatus, a putative membrane-bound complex encoded by the rnfABCDGEH operon is thought to be dedicated to electron transport to nitrogenase . In this study, the whole rnf operon was cloned under the control of the nifH promoter in plasmid pNR117 and expressed in several rnf mutants . Complementation analysis demonstrated that transconjugants which integrated plasmid pNR117 directed effective biosynthesis of a functionally competent complex in R . capsulatus . Moreover, it was found that strains carrying pNR117 displayed nitrogenase activities 50 to 100% higher than the wild-type level . The results of radioactive labeling experiments indicated that the intracellular content of nitrogenase polypeptides was marginally altered in strains containing pNR117, whereas the levels of the RnfB and RnfC proteins present in the membrane were four- and twofold, respectively, higher than the wild-type level . Hence, the enhancement of in vivo nitrogenase activity was correlated with a commensurate overproduction of the Rnf polypeptides . In vitro nitrogenase assays performed in the presence of an artificial electron donor indicated that the catalytic activity of the enzyme was not increased in strains overproducing the Rnf polypeptides . It is proposed that the supply of reductants through the Rnf complex might be rate limiting for nitrogenase activity in vivo . Immunoprecipitation experiments performed on solubilized membrane proteins revealed that RnfB and RnfC are associated with each other and with additional polypeptides which may be components of the membrane-bound complex. J Bacteriol, 2000 Mar, 182(5), 1200 - 7 Role of the H protein in assembly of the photochemical reaction center and intracytoplasmic membrane in Rhodospirillum rubrum; Cheng YS et al.; Rhodospirillum rubrum is a model for the study of membrane formation . Under conditions of oxygen limitation, this facultatively phototrophic bacterium forms an intracytoplasmic membrane that houses the photochemical apparatus . This apparatus consists of two pigment-protein complexes, the light-harvesting antenna (LH) and photochemical reaction center (RC) . The proteins of the photochemical components are encoded by the puf operon (LHalpha, LHbeta, RC-L, and RC-M) and by puhA (RC-H) . R . rubrum puf interposon mutants do not form intracytoplasmic membranes and are phototrophically incompetent . The puh region was cloned, and DNA sequence determination identified open reading frames bchL and bchM and part of bchH; bchHLM encode enzymes of bacteriochlorophyll biosynthesis . A puhA/G115 interposon mutant was constructed and found to be incapable of phototrophic growth and impaired in intracytoplasmic membrane formation . Comparison of properties of the wild-type and the mutated and complemented strains suggests a model for membrane protein assembly . This model proposes that RC-H is required as a foundation protein for assembly of the RC and highly developed intracytoplasmic membrane . In complemented strains, expression of puh occurred under semiaerobic conditions, thus providing the basis for the development of an expression vector . The puhA gene alone was sufficient to restore phototrophic growth provided that recombination occurred. Proc R Soc Lond B Biol Sci, 2000 Jan 7, 267(1438), 69 - 73 Sex-ratio-distorting Wolbachia causes sex-role reversal in its butterfly host; Jiggins FM et al.; Sex-role-reversed mating systems in which females compete for males and males may be choosy are usually associated with males investing more than females in offspring . We report that sex-role reversal may also be caused by selfish genetic elements which distort the sex ratio towards females . Some populations of the butterflies Acraea encedon and Acraea encedana are extremely female biased because over 90% of females are infected with a Wolbachia bacterium that is maternally inherited and kills male embryos . Many females in these populations are virgins suggesting that their reproductive success may be limited by access to males . These females form lekking swarms at landmarks in which females exhibit behaviours which we interpret as functioning to solicit matings from males . The hypothesis that female A . encedon swarm in order to mate is supported by the finding that, in release recapture experiments, mated females tend to leave the swarm while unmated females remained . This behaviour is a sex-role-reversed form of a common mating system in insects in which males form lekking swarms at landmarks and compete for females . Female lekking swarms are absent from less female-biased populations and here the butterflies are instead associated with resources in the form of the larval food plant. J Med Microbiol, 2000 Feb, 49(2), 139 - 47 Ultrastructural study of Mycobacterium avium infection of HT-29 human intestinal epithelial cells; Sangari FJ et al.; Mycobacterium avium is a common pathogen in AIDS patients and, in a large percentage of those patients, M . avium infection appears to be acquired via the gastrointestinal tract . M . avium is able to bind to and enter human and murine intestinal epithelial cells in vitro and in vivo . The invasion by and intracellular fate of M . avium in the HT-29 intestinal epithelial cell line was examined in an ultrastructural study . Bacterial contact with polarised cells was observed 10-15 min after monolayer infection and in polarised monolayers this always occurred in areas lacking microvilli . Contact with HT-29 cells did not appear to take place in a preferential area on the bacterial cell . Following invasion, M . avium was encountered within vacuoles containing either single or multiple bacteria; the latter evolved to contain only an individual bacterium . Vacuoles containing more than one bacterium were seen early in the infection and eventually underwent segmentation, with each bacterium occupying a vacuole . No bacteria were observed outside vacuoles up to 5 days after infection. Acta Crystallogr D Biol Crystallogr, 2000 Jan, 56 ( Pt 1), 3 - 13 The three-dimensional structure of a Trichoderma reesei beta-mannanase from glycoside hydrolase family 5; Sabini E et al.; The crystal structure of the catalytic core domain of beta-mannanase from the fungus Trichoderma reesei has been determined at a resolution of 1.5 A . The structure was solved using the anomalous scattering from a single non-isomorphous platinum complex with two heavy-metal sites in space group P2(1) . The map computed with the experimental phases was enhanced by the application of an automated model building and refinement procedure using the amplitudes and experimental phases as observations . This approach is expected to be of more general application . The structure of the native enzyme and complexes with Tris-HCl and mannobiose are also reported: the mannobiose binds in subsites +1 and +2 . The structure is briefly compared with that of the homologous beta-mannanase from the bacterium Thermomonospora fusca. Acta Crystallogr D Biol Crystallogr, 2000 Feb, 56 ( Pt 2), 215 - 7 Crystallization and preliminary X-ray analysis of a membrane-bound nitrite reductase from Desulfovibrio desulfuricans ATCC 27774; Dias JM et al.; Nitrite reductase from the sulfate-reducing bacterium Desulfovibrio desulfuricans ATCC 27774 is a multihaem (type c) membrane-bound enzyme that catalyzes the dissimilatory conversion of nitrite to ammonia . Crystals of the oxidized form of this enzyme were obtained using PEG and CaCl(2) as precipitants in the presence of 3--(decylmethylammonium)propane-1-sulfonate and belong to the space group P2(1)2(1)2(1), with unit-cell parameters a = 78.94, b = 104.59, c = 143.18 A . A complete data set to 2.30 A resolution was collected using synchrotron radiation at the ESRF . However, the crystals may diffract to beyond 1.7 A and high-resolution data will be collected in the near future. Chemosphere, 2000 Feb, 40(3), 319 - 25 The effect of EDTA and fulvic acid on Cd, Zn, and Cu toxicity to a bioluminescent construct (pUCD607) of Escherichia coli; Campbell CD et al.; The hypothesis, that metal toxicity is dominated by free ion activity, was tested by comparing calculated metal activities with measured toxic responses to a genetically modified, luminescent bacterium, Escherichia coli . The toxicity of Cd, Cu, and Zn sulphate salts in the presence of EDTA and fulvic acid in well-defined solutions was measured . Good agreement between free metal activity and toxicity was found for Cu but not for Zn and Cd . The toxicity relationships were altered by glucose addition to the organism . Stable chloride complexes may have contributed to the toxicity of Cd under the test conditions . The results suggest that there is not always a simple relationship between toxicity and free-ion metal concentration and that further account should be taken of competitive interactions between living cells and ligands and the physiological status of the organism. Trends Biochem Sci, 2000 Feb, 25(2), 74 - 9 Lesions in DNA: hurdles for polymerases; Baynton K et al.; Translesion synthesis (TLS) is one of the DNA damage tolerance strategies, which have evolved to enable organisms to replicate their genome despite the presence of unrepaired damage . The process of TLS has the propensity to produce mutations, a potential origin of cancer, and is therefore of medical interest . Significant progress in our understanding of TLS has come primarily from studies of the bacterium Escherichia coli, the budding yeast Saccharomyces cerevisiae and, more recently, human cells . Results from these analyses indicate that the fundamental mechanism of TLS and the proteins involved have been conserved throughout evolution from bacteria to humans. Cell Signal, 1999 Dec, 11(12), 863 - 9 Activation of arachidonate release and cytosolic phospholipase A2 via extracellular signal-regulated kinase and p38 mitogen-activated protein kinase in macrophages stimulated by bacteria or zymosan; Hiller G et al.; The mitogen-activated protein kinases (MAP kinases), extracellular signal-regulated kinase (ERK) and p38, can both contribute to the activation of cytosolic phospholipase A2 (cPLA2) . We have investigated the hypothesis that ERK and p38 together or independent of one another play roles in the regulation of cPLA2 in macrophages responding to the oral bacterium Prevotella intermedia or zymosan . Stimulation with bacteria or zymosan beads caused arachidonate release and enhanced in vitro cPLA2 activity of cell lysate by 1.5- and 1.7-fold, respectively, as well as activation of ERK and p38 . The specific inhibitor of MAP kinase kinase, PD 98059, and the inhibitor of p38, SB 203580, both partially inhibited cPLA2 activation and arachidonate release induced by bacteria and zymosan . Together, the two inhibitors had additive effects and completely blocked cPLA2 activation and arachidonate release . The present results demonstrate that ERK and p38 both have important roles in the regulation of cPLA2 and together account for its activation in P . intermedia and zymosan-stimulated mouse macrophages. Adv Exp Med Biol, 1999, 473, 207 - 14 Coiling phagocytosis is the predominant mechanism for uptake of the colonic spirochetosis bacterium Serpulina pilosicoli by human monocytes; Cheng X et al.; Serpulina pilosicoli is a newly identified pathogenic spirochete that establishes persistent colonic infections in human beings and animals . Macrophages are one of the key defenses against invasion of mucosal surfaces by bacterial pathogens . Macrophages engulf many bacteria by conventional phagocytosis; however recent studies indicate coiling phagocytosis as a new and important mechanism for internalization of Legionella pneumophila and spirochetes of the genus Borrelia, Leptospira, and Treponema . In this study, THP-1 human monocytic cells were incubated with the human S . pilosicoli strain SP16 and the contribution of coiling and conventional phagocytosis to the total number of phagocytic events were determined by sequential ultrastructural examination between 5 and 45 minutes . The frequency of phagocytosis increased over time from 5.1% after 5 minutes up to 21.9% after 45 minutes with greater than 70% of the events involving coiling phagocytosis . The data indicate that coiling phagocytosis may be a universal mechanism for uptake of pathogenic spirochetes. Mil Med, 2000 Jan, 165(1), 21 - 7 Association of Helicobacter pylori infection with gastric cancer; Alexander GA et al.; BACKGROUND: Helicobacter pylori has generated public health interest since its identification in 1983 . Past studies have suggested that the bacterium plays a role in the pathogenesis of gastric cancer . More recent studies support the conclusion that the association of H . pylori with gastric cancer is causal . The purpose of this article is to review the available evidence supporting the association of H . pylori with gastric cancer . METHODS: We performed a critical review of the relevant literature published in the English language on H . pylori and gastric cancer using MEDLINE, Index Medicus for the years 1985 to 1997 . The reference lists of selected articles also were reviewed to capture citations for further pertinent studies . RESULTS: H . pylori is thought to be the major cause of chronic atrophic gastritis . H . pylori gastritis is worldwide in distribution . H . pylori is now categorized by the International Agency for Cancer Research as a group 1 carcinogen, i.e., an agent that is carcinogenic to humans . Several reports from the United States have found the highest frequencies of gastric cancer in geographic areas and populations with the highest rates of acquisition of H . pylori infection . The high prevalence of H . pylori infection has been documented most notably in blacks and Hispanics, who also are at high risk for gastric cancer . CONCLUSIONS: New studies that focus on the epidemiology and pathology of H . pylori improve our understanding of its relationship with gastric cancer and advance the development of gastric cancer prevention and control strategies that are proposed. Mol Plant Microbe Interact, 2000 Jan, 13(1), 6 - 13 Resistance of tomato line Hawaii7996 to Ralstonia solanacearum Pss4 in Taiwan is controlled mainly by a major strain-specific locus; Wang JF et al.; Bacterial wilt caused by the soilborne bacterium Ralstonia solanacearum attacks hundreds of plant species, including many agriculturally important crops . Natural resistance to this disease has been found in some species and is usually inherited as a polygenic trait . In tomato, a model crop plant, genetic analysis previously revealed the involvement of several QTL (quantitative trait loci) controlling resistance and, in all of these studies with different strains of the pathogen, loci on chromosome 6 played the predominant role in controlling this trait . Using quantitative data collected from a greenhouse test F3 population, we identified a new locus on chromosome 12 that appears to be active specifically against a race 1 biovar 3 Pss4 bacterial strain endemic to Taiwan . Chromosome 6 still contributes significantly to the control of the resistance, and weaker associations of the trait to other regions of the genome are observed . These results are discussed in the context of current molecular knowledge about the strain specificity of disease resistance genes. Eur J Gastroenterol Hepatol, 1999 Dec, 11(12), 1371 - 7 Antral gastric permeability to antigens in mice is altered by infection with Helicobacter felis; Matysiak-Budnik T et al.; OBJECTIVE: Gastric inflammation is observed not only during Helicobacter pylori infection but also after eradication of the bacterium . The hypothesis that an altered gastric permeability could be involved was tested using a model of mice infected with Helicobacter felis . DESIGN: The antral and corpus gastric permeability during infection and after eradication of bacteria was studied . METHODS: Gastric fragments from the antrum and corpus of healthy mice, mice infected with H . felis, or mice after bacterial eradication, were mounted in Ussing chambers, and fluxes of sodium (JNa), mannitol (JMan) and horseradish peroxidase (HRP) under intact (JHRPi) and degraded (JD) form were measured . RESULTS: In healthy mice, JNa, JMan, JHRPi and JD, respectively, were greater in the antrum (6.5 +/- 0.5 microEq/h.cm2; 0.137 +/- 0.016 micromol/h.cm2; 30.4 +/- 7.4 ng/h.cm2 and 852 +/- 173 ng/h.cm2) than in the corpus (5.0 +/- 0.3 microEq/h.cm2; 0.085 micro 0.013 micromol/h.cm2; 9.5 +/- 2.8 ng/h.cm2 and 434 +/- 139 ng/h.cm2) . In H . felis-infected mice, HRP fluxes in the antrum were increased (JHRPi = 182 +/- 86, JD = 948 +/- 94 ng/h.cm2) as compared to controls (JHRPi = 10.3 +/- 2.6, JD = 458 +/- 98 ng/h.cm2) . Bacterial eradication led to the reduction of intact (JHRPi = 53 +/- 26 ng/h.cm) but not of degraded (JD = 844 +/- 213 ng/h.cm) HRP fluxes . After eradication, degraded HRP fluxes returned to normal in mice without inflammation (JD = 558 +/- 36 ng/h.cm2) but not in those with persistent inflammation (JD = 987 +/- 310 ng/h.cm2) . CONCLUSIONS: The results suggest that during H . felis infection, bacterial colonization and inflammation lead to an increased gastric permeability along the direct and degradative pathways, respectively . Such an increased antigenic load could contribute to the perpetuation of gastric inflammation after bacterial eradication, and possibly to food protein sensitization. Appl Environ Microbiol, 2000 Feb, 66(2), 671 - 7 Cytochrome c(3) mutants of Desulfovibrio desulfuricans; Rapp-Giles BJ et al.; To explore the physiological role of tetraheme cytochrome c(3) in the sulfate-reducing bacterium Desulfovibrio desulfuricans G20, the gene encoding the preapoprotein was cloned, sequenced, and mutated by plasmid insertion . The physical analysis of the DNA from the strain carrying the integrated plasmid showed that the insertion was successful . The growth rate of the mutant on lactate with sulfate was comparable to that of the wild type; however, mutant cultures did not achieve the same cell densities . Pyruvate, the oxidation product of lactate, served as a poor electron source for the mutant . Unexpectedly, the mutant was able to grow on hydrogen-sulfate medium . These data support a role for tetraheme cytochrome c(3) in the electron transport pathway from pyruvate to sulfate or sulfite in D . desulfuricans G20. FEMS Microbiol Lett, 2000 Feb 1, 183(1), 55 - 61 Gene cloning, nucleotide sequence and biochemical properties of a cytoplasmic cyclomaltodextrinase (neopullulanase) from Alicyclobacillus acidocaldarius, reclassification of a group of enzymes; Matzke J et al.; A gene encoding a cyclomaltodextrinase (neopullulanase) was cloned from the thermoacidophilic bacterium Alicyclobacillus acidocaldarius ATCC27009 and its nucleotide sequence was determined . The encoded CdaA protein lacked an N-terminal signal sequence and aligned well with a family of bacterial proteins described as maltogenic alpha-amylases, neopullulanases or cyclomaltodextrinases . Escherichia coli cells harboring the cloned cdaA gene produced a 66-kDa protein that degraded pullulan in a sodium dodecyl sulfate-polyacrylamide gel . A . acidocaldarius cells grown on maltose, soluble starch or pullulan synthesized the same protein . Neopullulanase activity of the protein was cytoplasmic and its pH optimum of 5.5 was close to the pH value of the cytoplasm . CdaA degraded cyclomaltodextrins rapidly and pullulan (to panose) more slowly . It is proposed that CdaA functions as a cytoplasmic cyclomaltodextrinase (EC 3.2.1.54). Biochemistry (Mosc), 1999 Dec, 64(12), 1418 - 26 Phenoptosis: programmed death of an organism; Skulachev VP; Programmed cell death (apoptosis) is well-established in many multicellular organisms . Apoptosis purifies a tissue from cells that became useless or even harmful for the organism . Similar phenomena are already described also at subcellular level (suicide of mitochondria, i.e., mitoptosis) as well as at supracellular level (degradation of some organs temporarily appearing in the course of ontogenesis and then disappearing by means of apoptosis of the organ-composing cells) . Following the same logic, one may put a question about programmed death of an organism as a mechanism of purification of a kin, community of organisms, or population from individuals who became unwanted for this kin, etc . A putative mechanism of such kind is proposed to be coined "phenoptosis" by analogy with apoptosis and mitoptosis . In a unicellular organism (the bacterium Escherichia coli), three different biochemical mechanisms of programmed death are identified . All of them are actuated by the appearance of phages inside the bacterial cell . This may be regarded as a precedent of phenoptosis which prevents expansion of the phage infection among E . coli cells . Purification of a population from infected individuals looks like an evolutionary invention useful for a species . Such an invention has high chances to be also employed by multicellular organisms . Most probably, septic shock in animals and humans serves as an analog of the phage-induced bacterial phenoptosis . It is hypothesized that the stress-induced ischemic diseases of brain and heart as well as carcinogenesis if they are induced by repeated stresses also represent phenoptoses that, in contrast to sepsis, are age-dependent . There are interrelations of programmed death phenomena at various levels of complexity of the living systems . Thus, extensive mitoptosis in a cell leads to apoptotic death of this cell and extensive apoptosis in an organ of vital importance results in phenoptotic death of an individual . In line with this logic, some cases are already described when inhibition of apoptosis strongly improves the postischemic state of the organism. J Bacteriol, 2000 Feb, 182(4), 1158 - 61 Cell cycle arrest in archaea by the hypusination inhibitor N(1)-guanyl-1,7-diaminoheptane; Jansson BP et al.; Hypusination is an essential posttranslational modification unique to archaeal and eukaryotic protein synthesis initiation factor 5A (aIF5A and eIF5A, respectively) . We have investigated the effect of the efficient hypusination inhibitor N(1)-guanyl-1,7-diaminoheptane (GC(7)) on four archaeal and one bacterial species . We found that (i) archaea are sensitive to GC(7), whereas the bacterium Escherichia coli is not, (ii) GC(7) causes rapid and reversible arrest of growth of the archaeon Sulfolobus acidocaldarius, and (iii) the growth arrest is accompanied by a specific reversible arrest of the cell cycle prior to cell division . Our findings establish a link between hypusination and sustained growth of archaea and thereby provide the framework to study molecular details of archaeal cell cycle in connection with in vivo functions of hypusine and of aIF5A and eIF5A. J Bacteriol, 2000 Feb, 182(4), 983 - 92 Mutagenesis and functional characterization of the glnB, glnA, and nifA genes from the photosynthetic bacterium Rhodospirillum rubrum; Zhang Y et al.; Nitrogen fixation is tightly regulated in Rhodospirillum rubrum at two different levels: transcriptional regulation of nif expression and posttranslational regulation of dinitrogenase reductase by reversible ADP-ribosylation catalyzed by the DRAT-DRAG (dinitrogenase reductase ADP-ribosyltransferase-dinitrogenase reductase-activating glycohydrolase) system . We report here the characterization of glnB, glnA, and nifA mutants and studies of their relationship to the regulation of nitrogen fixation . Two mutants which affect glnB (structural gene for P(II)) were constructed . While P(II)-Y51F showed a lower nitrogenase activity than that of wild type, a P(II) deletion mutant showed very little nif expression . This effect of P(II) on nif expression is apparently the result of a requirement of P(II) for NifA activation, whose activity is regulated by NH(4)(+) in R . rubrum . The modification of glutamine synthetase (GS) in these glnB mutants appears to be similar to that seen in wild type, suggesting that a paralog of P(II) might exist in R . rubrum and regulate the modification of GS . P(II) also appears to be involved in the regulation of DRAT activity, since an altered response to NH(4)(+) was found in a mutant expressing P(II)-Y51F . The adenylylation of GS plays no significant role in nif expression or the ADP-ribosylation of dinitrogenase reductase, since a mutant expressing GS-Y398F showed normal nitrogenase activity and normal modification of dinitrogenase reductase in response to NH(4)(+) and darkness treatments. Structure Fold Des, 1999 Dec 15, 7(12), 1505 - 15 Conformational changes induced by phosphorylation of the FixJ receiver domain; Birck C et al.; BACKGROUND: A variety of bacterial adaptative cellular responses to environmental stimuli are mediated by two-component signal transduction pathways . In these phosphorelay cascades, histidine kinases transphosphorylate a conserved aspartate in the receiver domain, a conserved module in the response regulator superfamily . The main effect of this phosphorylation is to alter the conformation of the response regulator in order to modulate its biological function . The response regulator FixJ displays a typical modular arrangement, with a phosphorylatable N-terminal receiver domain and a C-terminal DNA-binding domain . In the symbiotic bacterium Sinorhizobium meliloti, phosphorylation of this response regulator activates transcription of nitrogen-fixation genes . RESULTS: The crystal structures of the phosphorylated and of the unphosphorylated N-terminal receiver domain of FixJ (FixJN) were solved at 2.3 A and 2.4 A resolution, respectively . They reveal the environment of the phosphoaspartate in the active site and the specific conformational changes leading to activation of the response regulator . Phosphorylation of the conserved aspartate induces major structural changes in the beta 4-alpha 4 loop, and in the signaling surface alpha 4-beta 5 that mediates dimerization of the phosphorylated full-length response regulator . A site-directed mutant at this protein-protein interface decreases the affinity of the phosphorylated response regulator for the fixK promoter tenfold . CONCLUSIONS: The cascade of phosphorylation-induced conformational changes in FixJN illustrates the role of conserved residues in stabilizing the phosphoryl group in the active site, triggering the structural transition and achieving the post-phosphorylation signaling events . We propose that these phosphorylation-induced conformational changes underly the activation of response regulators in general. C R Acad Sci III, 1999 Nov, 322(11), 973 - 8 Vaccination against infections by Chlamydia pneumoniae; Puolakkainen M et al.; Chlamydia pneumoniae is an intracellularly growing bacterium that causes respiratory infections and is strongly associated with atherosclerosis . Antibodies against C . pneumoniae are frequently encountered in the adult population, indicating past exposure to the micro-organism . Immunity to reinfection is, however, only partial and does not prevent development of sequelae . Infections caused by and associated with C . pneumoniae are a major cause of morbidity and mortality world wide . Development of a vaccine capable of protecting against infections due to C . pneumoniae and their sequelae would prevent up to 10% of community-acquired pneumonias in adults and add a new dimension to the prevention of atherosclerosis and coronary heart disease. Vet Pathol, 2000 Jan, 37(1), 47 - 53 Specific in situ hybridization of Haemobartonella felis with a DNA probe and tyramide signal amplification; Berent LM et al.; Haemobartonella felis is an epierythrocytic bacterium suspected to be the causative agent of feline infectious anemia . Previous studies with a polymerase chain reaction assay have identified a mycoplasmal 16S rRNA gene sequence that coincides with clinical disease and the presence of organisms in the blood . Tissues from a cat experimentally infected with H . felis were used for in situ hybridization studies to physically link this 16S rRNA gene to the organisms on the red cells . A biotin-labeled probe was used in conjunction with tyramide signal amplification to visualize the hybridization signal . This study clearly demonstrates a specific hybridization signal on the red cells in the tissues of the H . felis-infected cat . This in situ hybridization study is the final step in fulfilling the molecular guidelines for disease causation and proves that H . felis, a mycoplasmal organism, is the causative agent of feline infectious anemia. Infect Immun, 2000 Feb, 68(2), 779 - 90 Helicobacter felis infection is associated with lymphoid follicular hyperplasia and mild gastritis but normal gastric secretory function in cats; Simpson KW et al.; The relationship of Helicobacter felis, a bacterium observed in the stomachs of cats, to gastric disease is unclear . The objective of this study was to determine if H . felis infection alters gastric histopathology, proinflammatory cytokine expression, and secretory function and evokes a humoral immune response in cats . Five specific-pathogen-free (SPF) Helicobacter-free cats were studied before and for 1 year after oral inoculation with H . felis (ATCC 49179) . Four SPF H . felis-uninfected cats served as controls . The stomachs of all five H . felis-inoculated cats became colonized, as determined by urease activity, histopathology, PCR, culture, and transmission electron microscopy of serial gastric biopsies at 0, 3, 5, 8, and 12 months . Uninoculated cats remained Helicobacter free . Lymphoid follicular hyperplasia, atrophy, and fibrosis were observed primarily in the pylorus of infected cats . Mild mononuclear inflammation was detected in both infected and uninfected cats, but was more extensive in infected cats, with pangastric inflammation, eosinophilic infiltrates, and cardia gastritis observed only in infected cats . No upregulation of antral mucosal interleukin 1alpha (IL-1alpha), IL-1beta, or tumor necrosis factor alpha was detected by reverse transcription-PCR in any cat . The gastric secretory axes, assessed by fasting plasma gastrin, antral mucosal gastrin and somatostatin immunoreactivity, and pentagastrin-stimulated gastric acid secretion, were similar in both infected and uninfected cats . Gradual seroconversion (immunoglobulin G) was observed in four of five infected cats, with enzyme-linked immunosorbent assay values reaching 4x to 12x baseline 12 months postinfection . These findings indicate that H . felis infection in cats induces lymphoid follicular hyperplasia, mild gastritis, and seroconversion, but is associated with normal gastric secretory function. Proc Natl Acad Sci U S A, 2000 Jan 18, 97(2), 859 - 64 Genetic analysis of a bacterial genetic exchange element: the gene transfer agent of Rhodobacter capsulatus; Lang AS et al.; An unusual system of genetic exchange exists in the purple nonsulfur bacterium Rhodobacter capsulatus . DNA transmission is mediated by a small bacteriophage-like particle called the gene transfer agent (GTA) that transfers random 4.5-kb segments of the producing cell's genome to recipient cells, where allelic replacement occurs . This paper presents the results of gene cloning, analysis, and mutagenesis experiments that show that GTA resembles a defective prophage related to bacteriophages from diverse genera of bacteria, which has been adopted by R . capsulatus for genetic exchange . A pair of cellular proteins, CckA and CtrA, appear to constitute part of a sensor kinase/response regulator signaling pathway that is required for expression of GTA structural genes . This signaling pathway controls growth-phase-dependent regulation of GTA gene messages, yielding maximal gene expression in the stationary phase . We suggest that GTA is an ancient prophage remnant that has evolved in concert with the bacterial genome, resulting in a genetic exchange process controlled by the bacterial cell. Nucleic Acids Res, 2000 Feb 1, 28(3), 706 - 9 Structural analysis of DNA sequence: evidence for lateral gene transfer in Thermotoga maritima; Worning P et al.; The recently published complete DNA sequence of the bacterium Thermotoga maritima provides evidence, based on protein sequence conservation, for lateral gene transfer between Archaea and Bacteria . We introduce a new method of periodicity analysis of DNA sequences, based on structural parameters, which brings independent evidence for the lateral gene transfer in the genome of T.maritima . The structural analysis relates the Archaea-like DNA sequences to the genome of Pyrococcus horikoshii . Analysis of 24 complete genomic DNA sequences shows different periodicity patterns for organisms of different origin . The typical genomic periodicity for Bacteria is 11 bp whilst it is 10 bp for Archaea . Eukaryotes have more complex spectra but the dominant period in the yeast Saccharomyces cerevisiae is 10.2 bp . These periodicities are most likely reflective of differences in chromatin structure. Mol Microbiol, 2000 Jan, 35(1), 90 - 100 Initial events in the degradation of the polycistronic puf mRNA in Rhodobacter capsulatus and consequences for further processing steps; Heck C et al.; Individual segments of the polycistronic puf mRNA of Rhodobacter capsulatus exhibit extremely different half-lives contributing to the stoichiometry of light-harvesting and reaction centre complexes of this facultative phototrophic bacterium . While earlier investigations shed light on the processes leading to the degradation of the 2.7 kb pufBALMX mRNA and, consequently, to the formation of the highly stable 0.5 kb pufBA mRNA processing product, we have now investigated the initial events in the degradation of the highly unstable 3.2 kb pufQBALMX primary transcript . Sequence modifications of two putative RNase E recognition sites within the pufQ coding region provide strong evidence that RNase E-mediated cleavage of a sequence at the 3' end of pufQ is involved in rate-limiting cleavage of the primary pufQBALMX transcript in vivo . The putative RNase E recognition sequence at the 5' end of pufQ is cleaved in vitro but does not contribute to rate-limiting cleavage in vivo . Analysis of the decay of puf mRNA segments transcribed from wild-type and mutated puf DNA sequences in R . capsulatus and Escherichia coli reveal that RNase E-mediated cleavage within the pufQ mRNA sequence also affects the stability of the 0.5 kb pufBA processing product . These findings demonstrate that the stability of a certain mRNA segment depends on the pathway of processing of its precursor molecule. Eur J Biochem, 2000 Jan, 267(2), 450 - 6 Pigments and proteins in green bacterial chlorosomes studied by matrix-assisted laser desorption ionization mass spectrometry; Persson S et al.; We have used matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) for mass determination of pigments and proteins in chlorosomes, the light-harvesting organelles from the photosynthetic green sulfur bacterium Chlorobium tepidum . By applying a small volume (1 microL) of a concentrated suspension of isolated chlorosomes directly to the target of the mass spectrometer we have been able to detect bacteriochlorophyll a and all the major homologs of bacteriochlorophyll c . The peak heights of the different bacteriochlorophyll c homologs in the MALDI spectra were proportional to peak areas obtained from HPLC analysis of the same sample . The same result was also obtained when whole cells of Chl . tepidum were applied to the target, indicating that MALDI-MS can provide a rapid method for obtaining a semiquantitative determination or finger-print of the bacteriochlorophyll homologs in a small amount of green bacterial cells . In addition to information on pigments, the MALDI spectra also contained peaks from chlorosome proteins . Thus we have been able with high precision to confirm the molecular masses of the chlorosome proteins CsmA and CsmE which have been previously determined by conventional biochemical and genetic methods, and demonstrate the presence of truncated versions of CsmA and CsmB. J Invertebr Pathol, 2000 Jan, 75(1), 55 - 8 Pathogenicity, development, and reproduction of Heterorhabditis bacteriophora and Steinernema carpocapsae under axenic in vivo conditions; Han R et al.; Galleria mellonella larvae cultured axenically were treated with axenic dauer juveniles of Heterorhabditis bacteriophora and Steinernema carpocapsae . After 3 days S . carpocapsae had killed all insects, with 9.4 +/- 4.3 nematodes per larva . H . bacteriophora were unable to kill G . mellonella, although 13.3 +/- 6.4 nematodes per Galleria were found in the hemocoel . Invading nematodes of both strains recovered from the dauer stage . H . bacteriophora developed into hermaphrodites with eggs and J1 in the uterus and in the hemolymph of the living insects . Development beyond the J1 stage was not recorded . An injection of supernatants from different Photorhabdus luminescens cultures killed the insects but could not provide nutrients to support a further development . Only the injection of bacterial cells supported production of dauers in the axenic insects . Axenic S . carpocapsae developed to adults and produced offspring . After 3 weeks an average of 5275 nematodes per larva were counted, of which 6.7% were dauer juveniles, 39.2% other juvenile stages, 11.9% males, and 42.2% females . Compared to in vivo reproduction in the presence of the symbiotic bacterium Xenorhabdus nematophilus the dauer juvenile yields were low . Even after 5 weeks the percentage of dauer juveniles did not surpass 10% . J Invertebr Pathol, 2000 Jan, 75(1), 47 - 54 Pathogenicity caused by high virulent and low virulent strains of Steinernema carpocapsae to Galleria mellonella; Simoes N et al.; Steinernema carpocapsae is an entomopathogenic nematode associated with a symbiotic bacterium, Xenorhabdus nematophilus . Both components of the complex participate in a pathogenic process in insects . This has raised two questions: how much does each one participate, and what mechanisms are involved? In this paper we compare the virulence of two strains of S . carpocapsae: a high virulent strain (Breton) and a low virulent strain (Az27), both of which are free of symbiotic bacteria . Breton and Az27 strains each one have similar ability to invade Galleria mellonella with median infectious times of 3.9 and 3.2 h, respectively . However, the LD(50) of the Breton and Az27 strains are 48.6 and 894.5 infective juveniles per insect, respectively . Breton strain takes 38 h to kill 100% of exposed insects, whereas Az27 takes three times longer . The lethal time of the low virulent strain in G . mellonella larvae is highly dependent on the number of nematodes which have penetrated the hemocelium, whereas it is not on the high virulent strain . Hemolymph patterns in SDS-PAGE of insects parasitized by the high virulent strain showed important differences in respect to the low virulent strain and control . Secretion/excretion products of the high virulent strain have important proteolytic activity as well as alpha-mannosidase and alpha-fucosidase activities, whereas, in secretion/excretion products of the avirulent strain, proteolytic activity was lower and alpha-mannosidase and alpha-fucosidase activities were undetected . Dig Dis Sci, 1999 Dec, 44(12), 2397 - 404 Potential relevance of agmatine as a virulence factor of Helicobacter pylori; Molderings GJ et al.; The polyamine agmatine is able to increase gastric acid secretion . Therefore, we investigated whether Helicobacter pylori is able to form and release agmatine in vitro and in the human stomach in vivo, and if so, whether a relationship exists among agmatine concentration in gastric juice, H . pylori infection, and gastroduodenal lesions . Agmatine was determined by means of HPLC . In the supernatant of H . pylori cultures, agmatine concentrations up to 1500 ng/ml (approximately 12 microM) were determined, depending on the number of the bacteria in the individual cultures . Agmatine concentration in gastric juice from H . pylori-positive patients was higher than in that from H . pylori-negative patients . Gastrin in blood was elevated in H . pylori-positive patients compared with H . pylori-negative patients . Agmatine concentration in gastric juice and serum gastrin level appeared to be related . In conclusion, H . pylori is able to form and to release agmatine in vitro and in vivo . This may be assumed to be relevant in vivo, since higher amounts of agmatine are present in gastric juice from H . pylori-positive than from H . pylori-negative patients . Accordingly, agmatine produced by H . pylori may be a virulence factor of this bacterium and may be involved in the pathogenesis of gastroduodenal lesions. J Bacteriol, 2000 Jan, 182(2), 286 - 94 Biochemical and molecular characterization of phenylacetate-coenzyme A ligase, an enzyme catalyzing the first step in aerobic metabolism of phenylacetic acid in Azoarcus evansii; El-Said Mohamed M; Phenylacetate-coenzyme A ligase (PA-CoA ligase; AMP forming, EC 6.2 . 1.30), the enzyme catalyzing the first step in the aerobic degradation of phenylacetate (PA) in Azoarcus evansii, has been purified and characterized . The gene (paaK) coding for this enzyme was cloned and sequenced . The enzyme catalyzes the reaction of PA with CoA and MgATP to yield phenylacetyl-CoA (PACoA) plus AMP plus PPi . The enzyme was specifically induced after aerobic growth in a chemically defined medium containing PA or phenylalanine (Phe) as the sole carbon source . Growth with 4-hydroxyphenylacetate, benzoate, adipate, or acetate did not induce the synthesis of this enzyme . This enzymatic activity was detected very early in the exponential phase of growth, and a maximal specific activity of 76 nmol min(-1) mg of cell protein(-1) was measured . After 117-fold purification to homogeneity, a specific activity of 48 micromol min(-1) mg of protein(-1) was achieved with a turnover number (catalytic constant) of 40 s(-1) . The protein is a monomer of 52 kDa and shows high specificity towards PA; other aromatic or aliphatic acids were not used as substrates . The apparent K(m) values for PA, ATP, and CoA were 14, 60, and 45 microM, respectively . The PA-CoA ligase has an optimum pH of 8 to 8.5 and a pI of 6.3 . The enzyme is labile and requires the presence of glycerol for stabilization . The N-terminal amino acid sequence of the purified protein showed no homology with other reported PA-CoA ligases . The gene encoding this enzyme is 1, 320 bp long and codes for a protein of 48.75 kDa (440 amino acids) which shows high similarity with other reported PA-CoA ligases . An amino acid consensus for an AMP binding motif (VX2SSGTTGXP) was identified . The biochemical and molecular characteristics of this enzyme are quite different from those of the isoenzyme catalyzing the same reaction under anaerobic conditions in the same bacterium. Res Microbiol, 2000 Nov, 151(9), 747 - 54 Characterization of the 16S rRNA gene V2 region and the rrn operons of Gardnerella vaginalis; Nath K et al.; Ribosomal RNA (rRNA) gene polymorphism was apparent when Gardnerella vaginalis DNA restriction profiles were hybridized with nonradioactively labeled total rRNA isolated from this bacterium . In contrast, use of a polymerase chain reaction (PCR)-based 16S rRNA gene V2 region resulted in a 118-bp V2-PCR amplicon that was specific and common in all 30 tested G . vaginalis isolates . In addition to providing a G . vaginalis-specific fingerprint, when the V2-PCR amplicon along with total rRNA were utilized as probes, a partial rRNA gene restriction map could be constructed . G . vaginalis contains two rrn operons with an EcoRI fragment of 1.6 kb common to both. Ned Tijdschr Geneeskd, 1999 Dec 11, 143(50), 2505 - 7 {Eradication of Helicobacter pylori possibly followed by gastroesophageal reflux disease}; Loffeld RJ; Colonisation with Helicobacter pylori exerts several effects on the production of acid . The bacterium does not play a direct role in the pathogenesis of gastroesophageal reflux disease (GORD) . Successful eradication of H . pylori in patients with ulcer disease appears to be followed by an increase in incidence of GORD . It has been postulated that the infection could protect against the development of GORD . H . pylori ulcers and gastritis should be treated by eradication therapy . It is unclear yet what is the best treatment in patients with H . pylori infection without an ulcus or gastritis. Biochemistry, 1999 Nov 30, 38(48), 15779 - 90 Comparison of the binding sites for high-potential iron-sulfur protein and cytochrome c on the tetraheme cytochrome subunit bound to the bacterial photosynthetic reaction center; Osyczka A et al.; A tetraheme cytochrome subunit bound to the photosynthetic reaction center (RC) of purple bacterium, Rubrivivax gelatinosus, interacts with two types of soluble electron donors, cytochromes c and high-potential iron-sulfur protein (HiPIP), at a binding domain in the vicinity of low-potential heme 1, the fourth heme from the special pair of bacteriochlorophyll . To clarify the mechanism of the interaction, the domain around heme 1 was examined using site-directed mutants that changed the surface charge in the region within 20 A from the heme edge . In the case of the interaction with soluble cytochrome c, a strong dependence on the sign of the introduced charge was observed in all mutants: positive charge inhibited the reaction rate, whereas additional negative charge accelerated it . This confirmed the electrostatic nature of the binding . Interaction with HiPIP was inhibited by a limited number of mutations at the close vicinity of heme 1, and no acceleration was observed (the effects of some mutations were independent of the sign of the introduced charge) . The acidic residues which were critically important for the binding of cytochrome c showed much less contribution to the binding of HiPIP . The binding site for HiPIP appears to be mostly formed by uncharged and hydrophobic residues, occupying a significantly smaller area than the cytochrome-c-binding site . It is proposed that the docking of HiPIP to the RC in Rvi . gelatinosus is primarily controlled by hydrophobic contacts between protein surfaces, thus differing from the electrostatic mode of the RC-cytochrome c interaction. J Mol Biol, 2000 Jan 14, 295(2), 279 - 88 Maltose-binding protein from the hyperthermophilic bacterium Thermotoga maritima: stability and binding properties; Wassenberg D et al.; Recombinant maltose-binding protein from Thermotoga maritima (TmMBP) was expressed in Escherichia coli and purified to homogeneity, applying heat incubation of the crude extract at 75 degrees C . As taken from the spectral, physicochemical and binding properties, the recombinant protein is indistinguishable from the natural protein isolated from the periplasm of Thermotoga maritima . At neutral pH, TmMBP exhibits extremely high intrinsic stability with a thermal transition >105 degrees C . Guanidinium chloride-induced equilibrium unfolding transitions at varying temperatures result in a stability maximum at approximately 40 degrees C . At room temperature, the thermodynamic analysis of the highly cooperative unfolding equilibrium transition yields DeltaG(N-->U)=100(+/-5) kJ mol(-1 )for the free energy of stabilization . Compared to mesophilic MBP from E . coli as a reference, this value is increased by about 60 kJ mol(-1) . At temperatures around the optimal growth temperature of T . maritima (t(opt) approximately 80 degrees C), the yield of refolding does not exceed 80 %; the residual 20 % are misfolded, as indicated by a decrease in stability as well as loss of the maltose-binding capacity . TmMBP is able to bind maltose, maltotriose and trehalose with dissociation constants in the nanomolar to micromolar range, combining the substrate specificities of the homologs from the mesophilic bacterium E . coli and the hyperthermophilic archaeon Thermococcus litoralis . Fluorescence quench experiments allowed the dissociation constants of ligand binding to be quantified . Binding of maltose was found to be endothermic and entropy-driven, with DeltaH(b)=+47 kJ mol(-1) and DeltaS(b)=+257 J mol(-1) K(-1) . Extrapolation of the linear vant'Hoff plot to t(opt) resulted in K(d) approximately 0.3 microM . This result is in agreement with data reported for the MBPs from E . coli and T . litoralis at their respective optimum growth temperatures, corroborating the general observation that proteins under their specific physiological conditions are in corresponding states . FEMS Microbiol Lett, 2000 Jan 15, 182(2), 259 - 64 A role for the bacterial outer membrane in the pathogenesis of Helicobacter pylori infection; Keenan J et al.; Helicobacter pylori infection in humans is associated with diverse of clinical outcomes which are partly attributed to bacterial strain differences . Secreted bacterial products are thought to be involved in the pathogenesis caused by this non-invasive bacterium . Electron microscopy of gastric biopsies from infected individuals revealed blebbing of the H . pylori outer membrane, similar to the process of outer membrane vesicle shedding which occurs when the bacterium is grown in broth . Porins, a class of proinflammatory proteins, were observed in the outer membrane vesicles . The VacA cytotoxin, which is produced by 50-60% of H . pylori strains and associated with increased pathogenesis of infection, was also found to be vesicle-associated and biologically active . This supports the hypothesis that these vesicles represent a vehicle for the delivery of damaging bacterial products to the gastric mucosa. Biochem J, 2000 Jan 15, 345 Pt 2, 255 - 62 Proteins isolated from lucerne roots by affinity chromatography with sugars analogous to Nod factor moieties; Minic Z et al.; Nod factors are important elicitors in legume-bacterium symbiosis . Any candidate plant receptor(s) for these lipo-oligosaccharides can be expected to show some lectin-like properties . A novel protein (P60), a native tetramer with 60 kDa monomers, has been isolated from a membrane fraction of Medicago sativa (lucerne, alfalfa) roots by using affinity chromatography with either GlcNAc or N,N', N"-triacetyl-(1-->4)-beta-d-chitotriose {(GlcNAc)(3)} grafted to agarose beads as the matrix and, in a second step, Sephadex G-200 gel filtration . With (GlcNAc)(3)-agarose an additional protein of 78 kDa was isolated . P60 showed haemagglutination activity with specificity for GalNAc, GalN, GlcNAc and GlcN . Binding experiments with radioactive GlcNAc gave a K(d) of 95 nM and one binding site per monomer of P60; Nod factor competed strongly for this binding . In native PAGE, protein incubated with O-sulphated Nod factors had a higher electrophoretic mobility as a consequence of binding . However, the largest modification was observed with a natural mixture of Nod factors, containing the O-acetylated and O-sulphated tetrasaccharidic NodRm-IV(Ac,S) (in which Ac stands for an O-acetylated group at the non-reducing end and S for O-sulphation at the reducing end) in addition to the non-O-acetylated NodRm-IV(S) (which alone had little effect) and NodRm-V(S) . The native PAGE study was also performed with known lectins from other sources, but only the 34 kDa lectin of Phytolacca americana (pokeweed) showed any such interaction, although without discrimination between Nod factors . Finally, one peptide of each isolated protein was sequenced; the peptide from P60 showed some similarity with dihydrolipoamide dehydrogenase and ferric leghaemoglobin reductase, whereas the peptide from P78 was identical with an analogous region of 70 kDa heat shock protein. FEMS Microbiol Ecol, 2000 Jan 1, 31(1), 61 - 71 Molecular detection of Gluconacetobacter sacchari associated with the pink sugarcane mealybug Saccharicoccus sacchari (Cockerell) and the sugarcane leaf sheath microenvironment by FISH and PCR; Franke IH et al.; Molecular tools for the detection of the newly described acetic acid bacterium Gluconacetobacter sacchari from the pink sugarcane mealybug, Saccharicoccus sacchari Cockerell (Homiptera: Pseudococcidae), and in the sugarcane leaf sheath microenvironment were developed . G . sacchari specific 16S rRNA-targeted oligonucleotide primers were designed and used in PCR amplification of G . sacchari DNA directly from mealybugs, and in a nested PCR to detect low numbers of the bacteria from sugarcane leaf sheath fluid and cane internode scrapings . A sensitivity level of detection of 40-400 cells/reaction was obtained using PCR from exponentially grown bacterial cultures and of 1-10 cells in cane internode scrapings and leaf sheath fluid samples using nested PCR . The specificity of the primer set was demonstrated by the lack of amplification product formation in PCR by closely related acetic acid bacteria, including Gluconacetobacter liquefaciens, and Gluconacetobacter diazotrophicus . A Cy3 labeled probe for G . sacchari was designed and shown to be specific for the species . Investigation of the mealybug microenvironment by whole cell fluorescent in situ hybridization revealed that G . sacchari appears to represent only a minor proportion of the population of the microbiota in the mealybugs tested . This study has shown the usefulness of 16S rRNA-based molecular tools in the identification and detection of G . sacchari from environmental samples and will allow these tools to be used in further ecological research. J Clin Microbiol, 2000 Jan, 38(1), 460 - 1 Isolation of Pantoea agglomerans in two cases of septic monoarthritis after plant thorn and wood sliver injuries; De Champs C et al.; Arthritis after plant injury is often apparently aseptic . We report two cases due to Pantoea agglomerans . In one case, the bacterium was isolated only from the pediatric blood culture media, BACTEC Peds Plus, monitored in BACTEC 9240, and not from the other media inoculated with the joint fluid . This procedure could help improve the diagnosis of septic arthritis. Mol Cell, 1999 Nov, 4(5), 683 - 94 Differential localization of two histidine kinases controlling bacterial cell differentiation; Wheeler RT et al.; The bacterium C . crescentus coordinates cellular differentiation and cell cycle progression via a network of signal transduction proteins . Here, we demonstrate that the antagonistic DivJ and PleC histidine kinases that regulate polar differentiation are differentially localized as a function of the cell cycle . The DivJ kinase localizes to the stalked pole in response to a signal at the G1-to-S transition, while the PleC kinase is localized to the flagellar pole in swarmer and predivisional cells but is dispersed throughout the cell in the stalked cell . PleC, which is required for DivJ localization, may provide the cue at the G1-to-S transition that directs the polar positioning of DivJ . The dynamic positioning of signal transduction proteins may contribute to the regulation of polar differentiation at specific times during the bacterial cell cycle. Appl Environ Microbiol, 2000 Jan, 66(1), 105 - 12 Induction of a futile Embden-Meyerhof-Parnas pathway in Deinococcus radiodurans by Mn: possible role of the pentose phosphate pathway in cell survival; Zhang YM et al.; Statistical models were used to predict the effects of tryptone, glucose, yeast extract (TGY) and Mn on biomass formation of the highly radioresistant bacterium Deinococcus radiodurans . Results suggested that glucose had marginal effect on biomass buildup, but Mn was a significant factor for biomass formation . Mn also facilitated glucose interactions with other nutrient components . These predictions were verified by in vivo and in vitro experiments . TGY-grown cells metabolized glucose solely by the pentose phosphate pathway (PPP) . Although only a fraction of glucose from the medium was transported into the cells, glucose was incorporated into the DNA efficiently after cells were exposed to UV light . The presence of glucose also enhanced the radioresistance of the culture . Mn could induce an Embden-Meyerhof-Parnas (EMP) pathway in D . radiodurans . The EMP pathway and the PPP of the Mn-treated cells oxidized glucose simultaneously at a 6:1 ratio . Although glucose was hydrolyzed rapidly by the Mn-treated cells, most glucose was released as CO(2) . Mn-treated cultures retained less glucose per cell than cells grown without Mn, and still less glucose was incorporated into the DNA after cells were exposed to UV light . Mn-treated cells were also more sensitive to UV light . Results suggested that metabolites of glucose generated from the PPP enhanced the survival of D . radiodurans . Induction of the EMP pathway by Mn may deplete metabolites for DNA repair and may induce oxidative stress for the cell, leading to reduction of radioresistance. J Bacteriol, 2000 Jan, 182(1), 107 - 15 flhDC, the flagellar master operon of Xenorhabdus nematophilus: requirement for motility, lipolysis, extracellular hemolysis, and full virulence in insects; Givaudan A et al.; Xenorhabdus is a major insect pathogen symbiotically associated with nematodes of the family Steinernematidae . This motile bacterium displays swarming behavior on suitable media, but a spontaneous loss of motility is observed as part of a phenomenon designated phase variation which involves the loss of stationary-phase products active as antibiotics and potential virulence factors . To investigate the role of one of the transcriptional activators of flagellar genes, FlhDC, in motility and virulence, the Xenorhabdus nematophilus flhDC locus was identified by functional complementation of an Escherichia coli flhD null mutant and DNA sequencing . Construction of X . nematophilus flhD null mutants confirmed that the flhDC operon controls flagellin expression but also revealed that lipolytic and extracellular hemolysin activity is flhDC dependent . We also showed that the flhD null mutant displayed a slightly attenuated virulence phenotype in Spodoptera littoralis compared to that of the wild-type strain . Thus, these data indicated that motility, lipase, hemolysin, or unknown functions controlled by the flhDC operon are involved in the infectious process in insects . Our investigation expands the view of the flagellar regulon as a checkpoint coupled to a major network involving bacterial physiological aspects as well as motility. Electrophoresis, 1999 Dec, 20(18), 3514 - 20 Classifying symbiotic proteins from Bradyrhizobium japonicum into functional groups by proteome analysis of altered gene expression levels; Dainese-Hatt P et al.; The advent of whole genome sequences has brought with it a vast number of new potential proteins whose function is unknown . We describe an approach to sorting proteins into functional groups by comparative two-dimensional (2-D) gel mapping of cells grown under different physiological conditions . Computerized image analysis selects the proteins whose expression levels change significantly for subsequent identification by mass spectrometry . The protein groupings are further subdivided by directed alteration of their expression levels (e.g., by gene inactivation) and following the changes in the expression pattern of the mutants . We have applied this approach to study the regulation of micro- and anaerobically induced genes including the genes involved in nitrogen fixation in the symbiotic bacterium Bradyrhizobium japonicum . The results obtained show that in addition to the two known regulons controlled by the transcription factors NifA and FixK2, a third set of proteins may exist in B . japonicum which are induced by anaerobic conditions and are regulated independently . The approach can be applied generally and can be used to build up functional relationship maps of genomes . Protein identification by mass spectrometry was shown to be vital to the interpretation of the expression analysis since 15% of the 2-D gel spots contained more than one protein. J Infect Dis, 2000 Jan, 181(1), 195 - 202 Borrelia burgdorferi--induced oxidative burst, calcium mobilization, and phagocytosis of human neutrophils are complement dependent; Suhonen J et al.; When Borrelia burgdorferi, the spirochete causing Lyme disease, is transmitted to a human, the complement system is among the first challenges facing the bacterium . Neutrophils are crucial leukocytes in the first line of host defense against bacterial infections . To investigate the role of complement in the Borrelia-induced activation of human neutrophils, oxidative burst, calcium mobilization, and phagocytosis induced by three subspecies of B . burgdorferi were studied . Each subspecies induced all observed neutrophil functions in a complement-dependent manner . Serum-derived factors bound to the surface of B . burgdorferi were found to be essential for the induction of the oxidative burst . The CD11b chain of CR3 was found to participate in the oxidative burst and calcium mobilization induced by B . burgdorferi. J Infect Dis, 2000 Jan, 181(1), 188 - 94 Repeated pregnancies in BALB/c mice infected with Coxiella burnetii cause disseminated infection, resulting in stillbirth and endocarditis; Stein A et al.; Q fever is a widespread zoonosis caused by the obligate intracellular bacterium Coxiella burnetii . Although this highly virulent organism is most concentrated in mammals during parturition, there are few reports on the manifestations of perinatal Q fever in the human and animal host . The affinity of C . burnetii to pregnancy and its abortifacient potential were investigated in a murine animal model . Intraperitoneal infection of female BALB/c mice with C . burnetii, followed by repeated pregnancies over a 2-year period, resulted in persistent infection associated with abortion and perinatal death, with a statistically significant decrease in viable offspring . In addition, endocarditis occurred in 2 of the adult animals, and C . burnetii antigen and DNA were detected in their heart valves . Taken together, these results demonstrate the abortifacient potential of C . burnetii and the increased risk of persistent infection and endocarditis in pregnant mice, probably related to a decline in cellular immunity during pregnancy. Arch Immunol Ther Exp (Warsz), 1999, 47(6), 347 - 53 Genomic catastrophism and the origin of vertebrate immunity; Hughes AL; Genomic catastrophism is the belief that unique genetic events, unlike those observed in recent evolutionary history, played a key role in the origin of vertebrate adaptations . Catastrophist hypotheses have been particularly popular is accounting for the origin of vertebrate specific immunity . Two major such hypotheses involve genome duplication by polyploidization and horizontal gene transfer . Recent analyses lead to decisive rejection of the widely cited hypothesis that the vertebrate genome underwent two rounds of genome duplication, and theoretical considerations suggest that genome duplication is unlikely to lead to new adaptive advances . Likewise, the evidence that key elements of the vertebrate immune system arose by horizontal transfer from a bacterium or by incorporation of a transposable element into the vertebrate genome remains relatively weak . Thus, at present, a uniformitarian view of the origin of the vertebrate immune system seems more reasonable, especially given the longer time-frame for vertebrate evolution indicated by molecular data. Microbes Infect, 1999 Apr, 1(5), 367 - 76 Clinical and biological aspects of infection caused by Ehrlichia chaffeensis; Rikihisa Y; Ehrlichia chaffeensis is an obligatory intracellular bacterium that infects the monocyte-macrophage . E . chaffeensis, which is transmitted to humans by ticks primarily from infected deer, causes human monocytic ehrlichiosis, an acute febrile systemic illness . This paper reviews current knowledge of clinical and biological aspects of infections caused by E . chaffeensis. Scand J Immunol, 1999 Dec, 50(6), 651 - 6 Antibodies given orally in the neonatal period can affect the immune response for two generations: evidence for active maternal influence on the newborn's immune system; Lundin BS et al.; Two day old Wistar rats were tube fed with 1 or 10 micrograms of a mouse IgG1 monoclonal anti-idiotypic (a-Id) antibody that was directed against an anti-Escherichia coli-K13 capsular polysaccharide antibody . A control group was given 10 micrograms of an unrelated control antibody . Six weeks after the administration of antibodies, the rats were intestinally colonised with an ovalbumin (OVA)-producing E . coli O6K13 strain . At 8 weeks of age, the male rats (first generation) and the offsprings of the female rats (second generation), were parenterally immunised with OVA and dead wild type E . coli O6K13, and the immune response was followed . In the rats of the first generation, there were no major differences between the groups in the immune response to the bacterium . However, the offspring of the neonatally a-Id administered rats had a profoundly affected immune response to the idiotypically connected antigen K13, but also to other antigens on the bacteria . Thus, a-Id treatment in the first generation gave, in the second generation, a greatly enhanced serum antibody response to the spatially related antigens OVA and O6 LPS, as well as to the idiotypically connected antigen K13 . Concurrently, the in vitro spleen cell proliferative response to both OVA and the wild type bacterium was lowered . Overall, greater effects were seen with the higher dose of a-Id . In conclusion, our results demonstrate that by giving monoclonal antibodies idiotypically connected to a single bacterial component to neonatal rats, one profoundly influence the immune response also to other-spatially related-bacterial antigens in their offsprings. Biospectroscopy, 1999, 5(6), 338 - 45 Certain species of the Proteobacteria possess unusual bacteriochlorophyll a environments in their light-harvesting proteins; Gall A et al.; In this work, we have examined, using Fourier-transform Raman (FT-R) spectroscopy, the bacteriochlorophyll a (BChl a) binding sites in light-harvesting (LH) antennae from different species of the Proteobacteria that exhibit unusal absorption properties . While the LH1 complexes from Erythromicrobium (E.) ramosum (RC-B871) and Rhodospirillum centenum (B875) present classic FT-R spectra in the carbonyl high-frequency region, we show that in the blue-shifted LH1 complex, absorbing at 856 nm, from Roseococcus thiosulfatophilus, as well as in the B798-832 LH2 from E . ramosum, or in the B830 complex from the obligate phototrophic bacterium Chromatium purpuratum, some H-bonds between the acetyl carbonyl of the BChl a and the surrounding protein are missing . The molecular mechanisms responsible for the unusual absorption of these complexes are thus similar to those responsible for tuning of the absorption of the LH2 complexes between 850 and 820 nm . Furthermore, our results suggest that the binding pocket of the monomeric BChl in the LH2 from E . ramosum is different from that of Rps . acidphila or Rb . sphaeroides . The FT-R spectra of Chromatium purpuratum indicate that, in contrast with every LH2 complex previously studied by FT-R spectroscopy, no free-from-interaction keto groupings exist in this complex. Infect Immun, 2000 Jan, 68(1), 125 - 32 Host and bacterial factors involved in the innate ability of mouse macrophages to eliminate internalized unopsonized Escherichia coli; Hamrick TS et al.; In an effort to better understand genetic and cellular factors that influence innate immunity, we examined host and bacterial factors involved in the nonopsonic phagocytosis and killing of Escherichia coli K-12 by mouse macrophages . Unelicited (resident) peritoneal macrophages from five different mouse strains, BALB/c, C57BL/6, CD-1, C3H/HeJ, and C3H/HeN, were employed . Additional macrophage populations were obtained from CD-1 mice (bone marrow-derived macrophages) . Also, for BALB/c and C57BL/6 mice, peritoneal macrophages elicited with either thioglycolate or proteose peptone, bone marrow-derived macrophages, and macrophage-like cell lines derived from the two strains were employed . Two E . coli K-12 strains that differed specifically in their abilities to produce type 1 pili containing the adhesive protein FimH were examined . The parameters used to assess macrophage bacteriocidal activity were (i) the killing of internalized (gentamicin-protected) E . coli during the approximately 4-h assay and (ii) the initial rate at which internalized E . coli were eliminated . Data on these parameters allowed the following conclusions: (i) unelicited or proteose peptone-elicited peritoneal macrophages were significantly better at eliminating internalized bacteria than thioglycolate-elicited peritoneal macrophages, bone marrow-derived macrophages, or macrophage cell lines; (ii) the host genetic background had no significant effect upon the ability of unelicited peritoneal macrophages to kill E . coli (even though the mouse strains differ widely in their in vivo susceptibilities to bacterial infection); and (iii) the FimH phenotype had no significant effect upon E . coli survival once the bacterium was inside a macrophage . Additionally, there was no correlation between the bacteriocidal effectiveness of a macrophage population and the number of bacteria bound per macrophage . However, macrophage populations that were the least bacteriocidal tended to bind higher ratios of FimH(+) to FimH(-) E . coli . The effect of gamma interferon, fetal calf serum, and the recombination proficiency of E . coli were examined as factors predicted to influence intracellular bacterial killing . These had no effect upon the rate of E . coli elimination by unelicited peritoneal macrophages. FEBS Lett, 1999 Dec 10, 463(1-2), 169 - 74 Identification of a hydrogen bond in the phe M197-->Tyr mutant reaction center of the photosynthetic purple bacterium Rhodobacter sphaeroides by X-ray crystallography and FTIR spectroscopy; Kuglstatter A et al.; In bacterial reaction centers the charge separation process across the photosynthetic membrane is predominantly driven by the excited state of the bacteriochlorophyll dimer (D) . An X-ray structure analysis of the Phe M197-->Tyr mutant reaction center from Rhodobacter sphaeroides at 2.7 A resolution suggests the formation of a hydrogen bond as postulated by Wachtveitl et al . {Biochemistry 32, 12875-12886, 1993} between the Tyr M197 hydroxy group and one of the 2a-acetyl carbonyls of D . In combination with electrochemically induced FTIR difference spectra showing a split band of the pi-conjugated 9-keto carbonyl of D, there is clear evidence for the existence of such a hydrogen bond. J Bacteriol, 1999 Dec, 181(24), 7464 - 9 Functional domains present in the mycobacterial hemagglutinin, HBHA; Delogu G et al.; Identification and characterization of mycobacterial adhesins and complementary host receptors required for colonization and dissemination of mycobacteria in host tissues are needed for a more complete understanding of the pathogenesis of diseases caused by these bacteria and for the development of effective vaccines . Previous investigations have demonstrated that a 28-kDa heparin-binding mycobacterial surface protein, HBHA, can agglutinate erythrocytes and promote mycobacterial aggregation in vitro . In this study, further molecular and biochemical analysis of HBHA demonstrates that it has three functional domains: a transmembrane domain of 18 amino acids residing near the N terminus, a large domain of 81 amino acids consistent with an alpha-helical coiled-coil region, and a Lys-Pro-Ala-rich C-terminal domain that mediates binding to proteoglycans . Using His-tagged recombinant HBHA proteins and nickel chromatography we demonstrate that HBHA polypeptides which contain the coiled-coil region form multimers . This tendency to oligomerize may be responsible for the induction of mycobacterial aggregation since a truncated N-terminal HBHA fragment containing the coiled-coil domain promotes mycobacterial aggregation . Conversely, a truncated C-terminal HBHA fragment which contains Lys-Pro-Ala-rich repeats binds to the proteoglycan decorin . These results indicate that HBHA contains at least three distinct domains which facilitate intercalation into surface membranes, promote bacterium-bacterium interactions, and mediate the attachment to sulfated glycoconjugates found in host tissues. Curr Microbiol, 2000 Feb, 40(2), 132 - 4 Isolation of intracytoplasmic membrane from the methanotrophic bacterium Methylomicrobium album BG8; Brantner CA et al.; Methane-oxidizing bacteria, including Methylomicrobium album BG8, form an intracytoplasmic membrane in addition to the cytoplasmic and outer membranes of the cell envelope . Techniques to isolate the intracytoplasmic membrane of M . album BG8 were developed . An intracytoplasmic membrane fraction was separated from a cell envelope fraction on the basis of sedimentation velocity in sucrose density gradients . Proteins associated with the particulate methane monooxygenase were found in both membrane fractions. J Immunol Methods, 1999 Nov 19, 230(1-2), 121 - 30 Fluobodies: green fluorescent single-chain Fv fusion proteins; Griep RA et al.; An expression system (pSKGFP), which permits the expression of single-chain variable fragments as fusion proteins with modified green fluorescent proteins, was designed . This expression system is comparable to frequently used phage display vectors and allows single-step characterization of the selected recombinant antibodies by flow cytometry or fluorescent cell staining . Two different single-chain variable fragment antibodies, both directed against the lipopolysaccharide of the bacterium Ralstonia solanacearum have been genetically fused to a red-shifted green fluorescent protein and the produced fusion protein tested for usefulness . These fluobodies can be produced in cultures of bacterial cells and purified using immobilized metal affinity chromatography . They function well in flow cytometry and immunofluorescent cell staining, are specific for their target antigens and, unlike FITC-conjugated antibodies, they do not fade upon illumination. J Microbiol Methods, 1999 Nov, 38(3), 183 - 9 Measurement of charge transfer during bacterial adhesion to an indium tin oxide surface in a parallel plate flow chamber; Poortinga AT et al.; An experimental method is described for the measurement of charge transfer during bacterial adhesion in situ to a transparent, semiconducting indium tin oxide (ITO) coated glass plate in a parallel plate flow chamber . Bacterial adhesion is measured simultaneously with either the electric potential or the capacitance of the surface . Initial bacterial adhesion was accompanied by a change in electric potential of the surface with no measurable change in capacitance . Consequently, it can be assumed that the change in electric potential of the surface is due to charge transfer between bacteria and the surface, and it can be calculated that, on average, a charge of about 10(-14) C per bacterium is exchanged during initial adhesion, which corresponds to only several percent of the total surface charge of a bacterium . Charge transfer could either be to or from the bacterial cell surface, dependent on the bacterial strain involved and the ionic strength used. Mutat Res, 1999 Nov 29, 430(1), 75 - 85 Intraclonal polymorphism in the bacterium Streptomyces ambofaciens ATCC23877: evidence for a high degree of heterogeneity of the wild type clones; Martin P et al.; In Streptomyces ambofaciens a genetic instability generates a high degree of polymorphism consisting of four main phenotypes: pigmented colonies (Pig(+) qualified as WT phenotype), pigment-defective colonies, pigmented colonies with pigment-defective sector and pigmented colonies with pigment-defective papillae . Molecular analysis of Pig(col)(-) and Pig(sec)(-) (pigment-defective mutant derived from a colony and a sector, respectively) produced by genetic instability and isolated in five Pig(+) subclones progenies revealed a new aspect of polymorphism in S . ambofaciens ATCC23877 . Frequencies of Pig(col)(-) and Pig(sec)(-) mutants deleted at the chromosome ends varied from one WT progeny to another . Two main types of deleted mutants were observed: deleted for one or both chromosomal extremities . The relative proportion of these two categories differed according to the WT progeny . These results argue for heterogeneity of the WT clones, i.e., Pig(+) colonies, originated from S . ambofaciens ATCC23877. Mol Gen Genet, 1999 Oct, 262(3), 501 - 7 A plasmid-based vector system for the cloning and expression of Helicobacter pylori genes encoding outer membrane proteins; Fischer W et al.; Helicobacter pylori produces a number of proteins associated with the outer membrane, including adhesins and the vacuolating cytotoxin . We observed that the functional expression of such proteins is deleterious to Escherichia coli, the host bacterium used for gene cloning . Therefore, a general method was developed for the functional expression of such genes on a shuttle vector in H . pylori, which has been termed SOMPES (Shuttle vector-based Outer Membrane Protein Expression System) . The intact, active gene is reconstituted by recombination in H . pylori from partial gene sequences cloned on an E . coli-H . pylori shuttle vector . This system was established in an H . pylori strain carrying a precise, unmarked chromosomal deletion of the vacA gene, which was constructed by adapting the streptomycin sensitivity system to H . pylori . It is based on the expression of the H . pylori rpsL gene as a counterselectable marker in the genetic background of an rpsL mutant . The utility of this approach is demonstrated by the expression of a recombinant gene encoding vacuolating cytotoxin (vacA) and a recombinant gene encoding an adherence-associated outer membrane protein (alpA) in H . pylori. Microbiology, 1999 Nov, 145 ( Pt 11), 3245 - 53 Novel Helicobacter pylori alpha1,2-fucosyltransferase, a key enzyme in the synthesis of Lewis antigens; Wang G et al.; Helicobacter pylori lipopolysaccharides (LPS) contain complex carbohydrates known as Lewis antigens which may contribute to the pathogenesis and adaptation of the bacterium . Involved in the biosynthesis of Lewis antigens is an alpha1,2-fucosyltransferase (FucT) that adds fucose to the terminal betaGal unit of the O-chain of LPS . Recently, the H . pylori (Hp) alpha1,2-FucT-encoding gene (fucT2) wa