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G Ayala

Publications and source records attributed to G Ayala.

61 records · Page 4Linked to original sources
PubMedDate not supplied

Characterization of the inorganic pyrophosphatase from the pathogenic bacterium Helicobacter pylori.

A cytoplasmic pyrophosphatase [E.C. 3.6.1.1.] was partially purified from Helicobacter pylori. The molecular mass was estimated to be 103 kDa by gel filtration. Results of SDS-PAGE suggested that the enzyme consists of six identical subunits of 19.1 kDa each. The enzyme specifically catalyzed the hydrolysis of pyrophosphate and was very sensitive to NaF, but not to sodium molybdate. The optimal pH for activity was 8.5. Mg2+ was required for maximal activity; Mn2+, Co2+, and Zn2+ poorly supported hydrolytic activity. The pyrophosphatase had an apparent K(m) for Mg-PP(i)2 hydrolysis of 90 microM, and a Vmax estimated at 24.0 micromol P(i) min(-1) mg(-1).

Amino Acid Sequence↗
PubMedDate not supplied

Helicobacter pylori: recent advances in the study of its pathogenicity and prevention.

Helicobacter pylori has acquired great importance during the last two decades, after being recognized as an important pathogen that infects a great portion of the human population. This microorganism is recognized as the main causal agent of chronic gastritis and duodenal ulcers, and it is associated with the subsequent development of gastric carcinoma. The pathogenic mechanisms of H. pylori and their relation to gastric ailments have not been clearly defined. However, at present it is well established that urease, vacuolating cytotoxin VacA, and the pathogenicity island (cag PAI) gene products, are the main factors of virulence of this organism. Thus, individuals infected with strains that express these virulence factors probably develop a severe local inflammation that may induce the development of peptic ulcer and gastric cancer. The way the infection spreads throughout the world suggests the possibility that there are multiple pathways of transmission. Due to the importance that H. pylori has acquired as a human pathogen, laboratories worldwide are attempting to develop a vaccine that confers long-term immunological protection against infection by this microorganism. Hence, the objective of this review is to present the most relevant findings of the biology of H. Pylori and its interaction with the human host.

Helicobacter Infections↗