Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0017160 (gastroenteritis)
 11,398 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Salmonella typhimurium is a Gram-negative bacterium responsible for human diseases including gastroenteritis and typhoid fever and its quorum sensing system is currently being intensively researched. Molecular modeling and binding site analysis of SdiA homolog, a putative quorum sensor of the LuxR family and responsible for S. typhimurium pathogenecity revealed a high structural homology of their active site with three other LuxR family proteins LasR from Pseudomonas aeruginosa, TraR from Agrobacterium tumifaciens and CviR from Chromobacterium violaceum. The results show that all the LuxR family proteins harbor three conserved amino acids Tryptophan (W67) and Aspartic acid (D80) for formation of hydrogen bridges and Tyrosine (Y71) for the hydrophobic interactions (corresponding to their position in S. typhimurium SdiA) with acyl homoserine lactones (AHL)-dependent transcriptional regulators. However, in addition to the above conserved residues, Arginine (R60) also plays an important role in S. typhimurium SdiA binding with its AHL auto inducers and the complex is found to be stronger because of the interactions between nitrogen atoms of Arginine with the carbonyl oxygen in the lactone ring of AHL. The specific binding patterns would be helpful in guiding both enzymatic studies as well as design of specific inhibitors to overcome S. typhimurium pathogenecity.
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PMID:Molecular modeling and active site analysis of SdiA homolog, a putative quorum sensor for Salmonella typhimurium pathogenecity reveals specific binding patterns of AHL transcriptional regulators. 2266 Sep 44

As an aquatic pathogen widely present in aquatic food, Vibrio parahaemolyticus causes outbreaks of gastroenteritis across the globe. Virulence factors of V. parahaemolyticus increases with the amount of spoilage in aquatic organisms including shrimp, but mechanisms regulating its virulence factors are not well understood. In this study, five spoilage bacteria isolated from shrimp were investigated for their regulatory effects on the virulence factors including haemolysin and biofilm of V. parahaemolyticus. Among these isolates, Shewanella putrefaciens induced haemolytic activity in V. parahaemolyticus in a time-dose-temperature-dependent manner and we found the main component responsible for this effect to be the supernatant or cell-free extract of S. putrefaciens. Total haemolytic activity, expression of the thermostable direct haemolysin gene tdh and biofilm production of V. parahaemolyticus were significantly up-regulated by S. putrefaciens, but also by deletion of quorum-sensing luxM or luxS gene of V. parahaemolyticus. However, this regulation by S. putrefaciens was significantly impaired by deletion of the luxM gene, but not by deletion of the luxS gene. Further study showed that S. putrefaciens exhibited a strong degradation ability on the signalling molecule acylated homoserine lactone (AHL) synthesised by the LuxM enzyme. This study revealed a novel virulence regulatory mechanism that S. putrefaciens can significantly increase the virulence factors of V. parahaemolyticus via interfering with the luxM- type quorum-sensing signalling pathway through its AHL-degradation ability.
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PMID:Regulatory effects of Shewanella putrefaciens isolated from shrimp Penaeus orientalis on the virulence factors of Vibrio parahaemolyticus and evaluation of the role of quorum sensing in virulence factors regulation. 2980 Jan 46