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Biometals : An International Journal on... Jun 2007Helicobacter species are among the most successful colonizers of the mammalian gastrointestinal and hepatobiliary tract. Colonization is usually lifelong, indicating... (Review)
Review
Helicobacter species are among the most successful colonizers of the mammalian gastrointestinal and hepatobiliary tract. Colonization is usually lifelong, indicating that Helicobacter species have evolved intricate mechanisms of dealing with stresses encountered during colonization of host tissues, like restriction of essential metal ions. The recent availability of genome sequences of the human gastric pathogen Helicobacter pylori, the murine enterohepatic pathogen Helicobacter hepaticus and the unannotated genome sequence of the ferret gastric pathogen Helicobacter mustelae has allowed for comparative genome analyses. In this review we present such analyses for metal transporters, metal-storage and metal-responsive regulators in these three Helicobacter species, and discuss possible contributions of the differences in metal metabolism in adaptation to the gastric or enterohepatic niches occupied by Helicobacter species.
Topics: Animals; Bacterial Outer Membrane Proteins; Biological Transport; Gene Expression Regulation, Bacterial; Helicobacter; Homeostasis; Humans; Membrane Transport Proteins; Metals; Molecular Sequence Data
PubMed: 17294126
DOI: 10.1007/s10534-006-9028-9 -
FEMS Immunology and Medical Microbiology Jun 1999Over the last decade animal models have been used extensively to investigate disease processes and therapy for Helicobacter pylori infections. The H. pylori animal... (Review)
Review
Over the last decade animal models have been used extensively to investigate disease processes and therapy for Helicobacter pylori infections. The H. pylori animal models which have been used in pathogenesis and vaccine studies include the gnotobiotic pig, non-human primates, cats, dogs, and several species of rodents including mice, rats, gerbils and guinea pigs. H. felis infection of mice and H. mustelae infection of ferrets have also been used. Recently, investigators have begun using transgenic mice and gene-targeted 'knock-out' mice to investigate Helicobacter infections. Each of these animal models has distinct advantages and disadvantages which are discussed in this minireview. The choice of an animal model is dictated by factors such as cost and an understanding of how each model will or will not allow fulfillment of experimental objectives.
Topics: Animals; Bacterial Vaccines; Cats; Disease Models, Animal; Dogs; Guinea Pigs; Helicobacter; Helicobacter Infections; Mice; Rats; Stomach Diseases
PubMed: 10378428
DOI: 10.1111/j.1574-695X.1999.tb01290.x -
Infection and Immunity Sep 1991Helicobacter mustelae is a urease-rich bacterium associated with gastritis in ferrets. The ureases of H. mustelae and Helicobacter pylori, a bacterium implicated in... (Comparative Study)
Comparative Study
Helicobacter mustelae is a urease-rich bacterium associated with gastritis in ferrets. The ureases of H. mustelae and Helicobacter pylori, a bacterium implicated in human gastritis, share many characteristics. Helicobacter sp. ureases appear to be unique among bacterial enzymes in exhibiting submillimolar Km values and in being composed of two subunits.
Topics: Campylobacter; Chromatography, Gel; Chromatography, High Pressure Liquid; Electrophoresis, Polyacrylamide Gel; Helicobacter pylori; Molecular Weight; Urease
PubMed: 1879950
DOI: 10.1128/iai.59.9.3343-3345.1991 -
Journal of Bacteriology Jun 1993Helicobacter pylori is one of the most common human pathogens. It causes chronic gastritis and is involved in the pathogenesis of gastroduodenal ulcer disease and... (Comparative Study)
Comparative Study
Cloning and genetic characterization of the Helicobacter pylori and Helicobacter mustelae flaB flagellin genes and construction of H. pylori flaA- and flaB-negative mutants by electroporation-mediated allelic exchange.
Helicobacter pylori is one of the most common human pathogens. It causes chronic gastritis and is involved in the pathogenesis of gastroduodenal ulcer disease and possibly gastric carcinoma. Helicobacter mustelae is a bacterium closely related to H. pylori that causes gastritis and ulcer disease in ferrets and is therefore considered an important animal model of gastric Helicobacter infections. Motility, even in a viscous environment, is conferred to the bacteria by several sheathed flagella and is regarded as one of their principal virulence factors. The flagellar filament of H. pylori consists of two different flagellin species expressed in different amounts. The gene (flaA) encoding the major flagellin has recently been cloned and sequenced. Here we report the cloning and sequencing of two highly homologous new flagellin genes from H. pylori 85P and H. mustelae NCTC 12032. The nucleotide sequence of the H. pylori gene proved that it encoded the second flagellin molecule found in H. pylori flagellar filaments. The genes were named flaB. The H. mustelae and H. pylori flaB genes both coded for proteins with 514 amino acids and molecular masses of 54.0 and 53.9 kDa, respectively. The proteins shared 81.7% identical amino acids. The degree of conservation between H. pylori FlaB and the H. pylori FlaA major flagellin was much lower (58%). Both flaB genes were preceded by sigma 54-like promoter sequences. Mapping of the transcription start site for the H. pylori flaB gene by a primer extension experiment confirmed the functional activity of the sigma 54 promoter. To evaluate the importance of both genes for motility, flaA- and flaB-disrupted mutants of H. pylori N6 were constructed by electroporation-mediated allelic exchange and characterized by Western blot (immunoblot) analysis and motility testing. Both mutations selectively abolished the expression of the targeted gene without affecting the synthesis of the other flagellin molecule. Whereas flaA mutants were completely nonmotile, flaB mutants retained motility.
Topics: Amino Acid Sequence; Bacterial Proteins; Base Sequence; Cell Movement; Flagellin; Genes, Bacterial; Helicobacter; Helicobacter pylori; Molecular Sequence Data; Phenotype; RNA, Messenger; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Transcription, Genetic; Transfection; Transformation, Genetic
PubMed: 8501031
DOI: 10.1128/jb.175.11.3278-3288.1993 -
Antimicrobial Agents and Chemotherapy Jun 1990Colonization of the ferret stomach by Helicobacter mustelae has been suggested as a possible animal model for Helicobacter pylori-associated gastroduodenal disease of...
Colonization of the ferret stomach by Helicobacter mustelae has been suggested as a possible animal model for Helicobacter pylori-associated gastroduodenal disease of humans. Our study was designed to determine whether antimicrobial chemotherapy could eradicate H. mustelae from ferrets. Triple antimicrobial therapy combining amoxicillin, metronidazole, and bismuth subsalicylate was successful in eradicating the organism from 5 of 7 (71%) adult ferrets. Despite apparent in vitro susceptibility, neither chloramphenicol monotherapy nor a polytherapeutic regimen combining tetracycline, metronidazole, and bismuth subsalicylate proved effective in the eradication of H. mustelae. Several strains isolated after unsuccessful polytherapy showed markedly increased resistance to metronidazole. These preliminary findings are similar to results of H. pylori treatment trials with humans and suggest that the ferret may be a useful model for evaluating and comparing potential antimicrobial modalities for the eradication of H. pylori.
Topics: Animals; Anti-Bacterial Agents; Campylobacter; Campylobacter Infections; Carnivora; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Ferrets; Gastroscopy; Microbial Sensitivity Tests; Stomach; Urease
PubMed: 2393285
DOI: 10.1128/AAC.34.6.1232 -
FEBS Letters Jun 2001The lipid A structure of the Gram-negative bacterium Helicobacter mustelae, a ferret gastric pathogen responsible for the onset of gastric diseases in its host, was... (Comparative Study)
Comparative Study
The lipid A structure of the Gram-negative bacterium Helicobacter mustelae, a ferret gastric pathogen responsible for the onset of gastric diseases in its host, was investigated. Two variant lipid A structures were found in the same strain. One structure contained a bisphosphorylated beta-(1-->6)-linked D-glucosamine backbone disaccharide with hydroxytetradecanoic acid in amide linkages. Unlike the structure described for the lipid A of the related human Helicobacter pylori gastric pathogen, which contains a C1 phosphate moiety, this lipid A presented phosphate groups at both the C1 and C4' positions, and contained no octadecanoyl fatty acid, which is present in H. pylori. The second lipid A structure had a different fatty acid composition in that 3-OH C(16) replaced most of the amide-linked 3-OH C(14).
Topics: Animals; Carbohydrate Conformation; Fatty Acids; Ferrets; Glucosamine; Helicobacter; Helicobacter pylori; Lipid A; Lipopolysaccharides; Magnetic Resonance Spectroscopy; Myristates; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 11418100
DOI: 10.1016/s0014-5793(01)02496-6 -
Infection and Immunity Jul 1995Helicobacter pylori is a human gastrointestinal pathogen involved in gastritis, duodenal ulcers, and gastric neoplasia. This microorganism produces large amounts of a...
Helicobacter pylori is a human gastrointestinal pathogen involved in gastritis, duodenal ulcers, and gastric neoplasia. This microorganism produces large amounts of a urease which, like all known ureases, has nickel in the active site. We have identified a protein in clinical isolates of H. pylori and an identical protein in the ferret pathogen Helicobacter mustelae that strongly binds Ni2+ and Zn2+. This protein has been named Hpn to emphasize its origins in H. pylori and its affinity for nickel. The encoding hpn gene, cloned and expressed in Escherichia coli ER1793, has an open reading frame (180 bp) that specifies a protein with a calculated molecular mass of 7,077 Da and with the same amino-terminal sequence as that of wild-type Hpn. The deduced sequence of Hpn consists of 60 amino acids, of which 28 (47%) are histidines. The hpn gene does not map with the urease gene cluster on the H. pylori chromosome. An Hpn-negative, isogenic H. pylori strain, generated by hpn gene deletion and grown on blood agar, had the same urease activity that wild-type cells did. Thus, the role of Hpn in helicobacters is unknown.
Topics: Amino Acid Sequence; Base Sequence; Cloning, Molecular; DNA, Bacterial; Genes, Bacterial; Helicobacter; Helicobacter pylori; Molecular Sequence Data; Nickel; Oligonucleotide Probes; Proteins; Restriction Mapping; Urease
PubMed: 7790085
DOI: 10.1128/iai.63.7.2682-2688.1995 -
Journal of Clinical Microbiology Feb 1991On the basis of analysis of protein profiles, isolates of Helicobacter pylori and Helicobacter mustelae were less than 40% similar. Cytotoxin produced by H. pylori was... (Comparative Study)
Comparative Study
On the basis of analysis of protein profiles, isolates of Helicobacter pylori and Helicobacter mustelae were less than 40% similar. Cytotoxin produced by H. pylori was not detected in isolates of H. mustelae. Both bacterial species agglutinated human erythrocytes. These results substantiate a taxonomic difference between H. pylori and H. mustelae.
Topics: Bacterial Proteins; Cytotoxins; Gram-Negative Anaerobic Bacteria; Helicobacter pylori; Hemagglutinins; Humans; Species Specificity; Virulence
PubMed: 2007648
DOI: 10.1128/jcm.29.2.395-397.1991 -
Infection and Immunity Jul 2000Isogenic flagellum-negative mutants of Helicobacter pylori and Helicobacter mustelae were screened for their ability to adhere to primary human and ferret gastric...
Isogenic flagellum-negative mutants of Helicobacter pylori and Helicobacter mustelae were screened for their ability to adhere to primary human and ferret gastric epithelial cells, respectively. We also evaluated the adherence of an H. pylori strain with a mutation in the flbA gene, a homologue of the flbF/lcrD family of genes known to be involved in the regulation of H. pylori flagellar biosynthesis. H. pylori and H. mustelae mutants deficient in production of FlaA or FlaB and mutants deficient in the production of both FlaA and FlaB showed no reduction in adherence to primary human or ferret gastric epithelial cells compared with the wild-type parental strains. However, adherence of the H. pylori flbA mutant to human gastric cells was significantly reduced compared to the adherence of the wild-type strain. These results show that flagella do not play a direct role in promoting adherence of H. pylori or H. mustelae to gastric epithelial cells. However, genes involved in the regulation of H. pylori flagellar biosynthesis may also regulate the production of an adhesin.
Topics: Adhesins, Bacterial; Animals; Bacterial Adhesion; Cells, Cultured; Epithelial Cells; Ferrets; Flagella; Gastric Mucosa; Genes, Bacterial; Helicobacter; Helicobacter pylori; Humans; In Vitro Techniques; Mutation
PubMed: 10858255
DOI: 10.1128/IAI.68.7.4335-4339.2000 -
Infection and Immunity Sep 1995Helicobacter mustelae infects the ferret stomach and provides an opportunity to study pathogenic determinants of a Helicobacter species in its natural host. We...
Helicobacter mustelae infects the ferret stomach and provides an opportunity to study pathogenic determinants of a Helicobacter species in its natural host. We constructed an isogenic urease-negative mutant of H. mustelae which produced no detectable urease and showed a reduced acid tolerance. This mutant provides an opportunity to further evaluate the role of urease in the pathogenesis of Helicobacter infection.
Topics: Amino Acid Sequence; Base Sequence; DNA Transposable Elements; Helicobacter; Hydrogen-Ion Concentration; Molecular Sequence Data; Mutation; Urease
PubMed: 7642313
DOI: 10.1128/iai.63.9.3718-3721.1995