Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:6.3.4.6 (urease)
 7,490 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The importance of hens eggs as a source of specific antibodies (IgY) is well recognized. The protective effect of IgY obtained from hens immunized with Helicobacter pylori whole-cell lysate has been reported for the control of H. pylori infection. However, IgY produced by whole-cell lysates presents the possibility of cross-reactivity with other bacteria, including the normal human flora, and this could decrease the efficiency of IgY. In the present study, the immunodominant proteins of H. pylori with reactivity to H. pylori-specific IgY (IgY-Hp) were identified. IgY obtained from hens immunized with various fractions of H. pylori proteins was isolated and purified, titres of IgY-Hp against H. pylori were determined and cross-reactivity between IgY-Hp and normal human bacteria was examined by Western blot analysis. Finally, immunodominant H. pylori proteins were identified by LC/MS analysis. IgY obtained 2 months after immunization with H. pylori whole-cell lysate showed the highest antibody titre. Five immunodominant proteins were identified that were strongly reactive to IgY-Hp: urease beta-subunit (62 kDa), heat-shock protein 60 (60 kDa), urease alpha-subunit (26 kDa), probable peroxiredoxin (22 kDa) and probable thiol peroxidase (18 kDa). Immunization of hens with the immunodominant proteins identified would produce a more specific IgY against H. pylori.
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PMID:Identification of immunodominant Helicobacter pylori proteins with reactivity to H. pylori-specific egg-yolk immunoglobulin. 1262 Oct 86

Helicobacter pylori (H. pylori) are resistant to hostile gastric environments and antibiotic therapy, reflecting the possibility that they are protected by an ecological niche, such as inside the vacuoles of human epithelial and immune cells. Candida yeast may also provide such an alternative niche, as fluorescently labeled H. pylori were observed as fast-moving and viable bacterium-like bodies inside the vacuoles of gastric, oral, vaginal and foodborne Candida yeasts. In addition, H. pylori-specific genes and proteins were detected in samples extracted from these yeasts. The H. pylori present within these yeasts produce peroxiredoxin and thiol peroxidase, providing the ability to detoxify oxygen metabolites formed in immune cells. Furthermore, these bacteria produce urease and VacA, two virulence determinants of H. pylori that influence phago-lysosome fusion and bacterial survival in macrophages. Microscopic observations of H. pylori cells in new generations of yeasts along with amplification of H. pylori-specific genes from consecutive generations indicate that new yeasts can inherit the intracellular H. pylori as part of their vacuolar content. Accordingly, it is proposed that yeast vacuoles serve as a sophisticated niche that protects H. pylori against the environmental stresses and provides essential nutrients, including ergosterol, for its growth and multiplication. This intracellular establishment inside the yeast vacuole likely occurred long ago, leading to the adaptation of H. pylori to persist in phagocytic cells. The presence of these bacteria within yeasts, including foodborne yeasts, along with the vertical transmission of yeasts from mother to neonate, provide explanations for the persistence and propagation of H. pylori in the human population. This Topic Highlight reviews and discusses recent evidence regarding the evolutionary adaptation of H. pylori to thrive in host cell vacuoles.
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PMID:Vacuoles of Candida yeast as a specialized niche for Helicobacter pylori. 2840 56