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Nicole Wüppenhorst Friederike von Loewenich Beate Hobmaier Marianne Vetter‐Knoll Sona Mohadjer Manfred Kist 《Helicobacter》2013,18(1):1-5
Helicobacter felis belongs to the fastidious gastric non‐Helicobacter pylori helicobacter species that are typically found in the stomach of cats and dogs. These bacteria have the potential to colonize the human stomach and are then associated with gastritis, gastroduodenal ulcers, and MALT lymphoma. Strains cultured from the human stomach are rare. Here, we present the first isolation of H. felis from a gastric biopsy specimen of a 14‐year‐old girl who presented with persistent epigastric pain. The strain was cultured using our routine protocol for H. pylori and identified by phylogenetic analyses of partial urease AB and gyrB gene sequences. 相似文献
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In Prince Edward Island, Canada, widespread intensive potato production has contributed to elevated nitrate concentrations in groundwater and streams, and eutrophic or anoxic conditions occur regularly in several estuarine systems. In this research, the stable isotopes of nitrogen and oxygen in nitrate in intertidal groundwater discharge and stream water were used, in conjunction with water quality and quantity data and land use information, to better understand the characteristics of nitrate delivered to two small estuaries with contrasting land use in their contributory catchments. Most of the water samples collected during the two-year study had isotopic signatures that fell in the range expected for nitrate derived from ammonium-based fertilizers (26.5 % of the samples) or in the overlapping range formed between ammonium-based fertilizers and nitrate derived from soil (64 % of the samples). Overall, isotopic signatures spanned over relatively narrow ranges, and correlations with other water quality parameters, or catchment characteristics, were weak. Nitrate in groundwater discharge and surface water in the Trout River catchment exhibited significantly different isotopic signatures only for the nitrogen isotope, while in the McIntyre Creek catchment groundwater discharge and surface water had similar isotopic signatures. When the isotopic results for the waters from the two catchments were compared, the surface waters were found to be similar, while the isotopic signatures of nitrate in groundwater were distinct only for the nitrogen isotope. Denitrification in the two study catchments was not evident based on the isotopic results for nitrate; however, in the case of the Trout River catchment, where a small freshwater pond exists, an average nitrate load reduction of 14 % was inferred based on a comparison of nitrate loads entering and leaving the pond. Overall, it appears that natural attenuation processes, occurring either in the streams or groundwater flow systems, do not significantly reduce nitrate loading to these estuaries. 相似文献
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The genome analysis of the gastrointestinal pathogens Helicobacter and Campylobacter has stimulated a wealth of new research activities, which are presented every 2 years at the international conferences on Campylobacter, Helicobacter and Related Organisms (CHRO). Both organisms represent excellent models for the identification of new molecular mechanisms involved in pathogenesis, host response and physiological adaptation in course of acute and chronic infectious diseases. The investigation of their global distribution, pronounced genetic and antigenic diversity as well as the molecular mechanisms allowing long-term persistence in hostile and unusual microbial habitats, is a challenge for scientists of many different disciplines world-wide. With a focus on the molecular microbiology aspects, this review summarizes recent trends in Helicobacter and Campylobacter research by highlighting selected presentations at the 11th CHRO conference. The topics include the discovery of new virulence factors, functional analysis of protein secretion systems, host signalling pathways, adaptation to stress conditions, global gene regulation, and genetic variability. 相似文献
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The functions of the riboflavin synthesis gene homologues ribA, ribBA, ribC, and ribD from Helicobacter pylori strain P1 were confirmed by complementation of defined Escherichia coli mutant strains. The H. pylori ribBA gene, which is similar to bifunctional ribBA genes of Gram-positive bacteria, fully complemented the ribB mutation and partially restored growth in a ribC mutant. However, ribBA did not complement the ribA mutation in E. coli, thus explaining the presence of the additional separate copy of the ribA gene in the H. pylori chromosome. In E. coli exclusively ribA conferred hemolytic activity and gave rise to production of molecules with fluorescence characteristics similar to flavins, as observed earlier. The E. coli hemolysin ClyA was not involved in causing the hemolytic phenotype. No riboflavin synthesis genes on plasmids conferred iron uptake functions to a siderophore-deficient mutant of E. coli. Marker exchange mutagenesis of the genes in H. pylori was not successful indicating that riboflavin synthesis is essential for basic metabolic functions of the gastric pathogen. 相似文献
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Identification and molecular analysis of superoxide dismutase isoforms in Helicobacter pylori 总被引:7,自引:0,他引:7
Three electromorphs of iron superoxide dismutase (FeSOD) were identified among 29 Helicobacter pylori isolates by native gel electrophoresis and activity staining. The electromorphs designated isoforms A, B, and C are characterized by slow, intermediate and fast electrophoretic migration, respectively, which was not observed under denaturing conditions. The isoforms were not associated with virulence determinants and with the outcome of disease. Sequence analysis of the sodB gene in strains producing different FeSOD isoforms and comparison of deduced protein sequences revealed that differences in the electric migration behavior are associated with exchange of charged amino acids, suggesting that faster migration is caused by a more negative total charge of the proteins. Electrophoretic migration of native FeSOD was not influenced by changes in the iron cofactor concentration, oxidative stress, and different media, indicating that FeSOD isoforms represent stable strain-specific markers. 相似文献
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Steven G. Smith Kaatje Smits Simone A. Joosten Krista E. van Meijgaarden Iman Satti Helen A. Fletcher Nadia Caccamo Francesco Dieli Francoise Mascart Helen McShane Hazel M. Dockrell Tom H. M. Ottenhoff TBVI TB Biomarker Working Group 《PloS one》2015,10(9)
Intracellular cytokine staining combined with flow cytometry is one of a number of assays designed to assess T-cell immune responses. It has the specific advantage of enabling the simultaneous assessment of multiple phenotypic, differentiation and functional parameters pertaining to responding T-cells, most notably, the expression of multiple effector cytokines. These attributes make the technique particularly suitable for the assessment of T-cell immune responses induced by novel tuberculosis vaccines in clinical trials. However, depending upon the particular nature of a given vaccine and trial setting, there are approaches that may be taken at different stages of the assay that are more suitable than other alternatives. In this paper, the Tuberculosis Vaccine Initiative (TBVI) TB Biomarker Working group reports on efforts to assess the conditions that will determine when particular assay approaches should be employed. We have found that choices relating to the use of fresh whole blood or peripheral blood mononuclear cells (PBMC) and frozen PBMC; use of serum-containing or serum-free medium; length of stimulation period and use of co-stimulatory antibodies can all affect the sensitivity of intracellular cytokine assays. In the case of sample material, frozen PBMC, despite some loss of sensitivity, may be more advantageous for batch analysis. We also recommend that for multi-site studies, common antibody panels, gating strategies and analysis approaches should be employed for better comparability. 相似文献
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Balabanova Y Gilsdorf A Buda S Burger R Eckmanns T Gärtner B Gross U Haas W Hamouda O Hübner J Jänisch T Kist M Kramer MH Ledig T Mielke M Pulz M Stark K Suttorp N Ulbrich U Wichmann O Krause G 《PloS one》2011,6(10):e25691