| Budget Amount *help |
¥3,960,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥360,000)
Fiscal Year 2007: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2006: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Research Abstract |
1. The presence of the quorum-sensing regulation system in Vibrio mimicus, a causative agent of food poisoning, was investigated. The culture supernatants of V. mimicus strains were found to possess Al-2 autoinducer like activity, and the strains were found to harbor the genes, which are homologous to luxS, luxO, and luxR of V harveyi. These genes of V hatveyi have been shown to be important components of V harveyi-like quorum-sensing system. The luxO gene homologue known to encode LuxO, the central component of the regulation system, was disrupted, and effects on protease and hemolysin activity were studied. Disruption of IuxO gene resulted in the increased protease activity, but the hemolysin activity did not vary considerably.
2. In Vibrio vulnificus that causes septicemia in humans, the extracellular proteins regulated by the quorum-sensing system were studied. The overall analysis of the proteins from a wild type strain and from a luxO mutant was carried out, and their profiles were compared. Production of more than 10 extracellular proteins was significantly affected by the genetic disruption of the luxO gene, indicating that the LuxO protein may be a global regulator in the quorum-sensing system. However, the mRNA levels of the proteins were not varied in the mutant. Therefore, the LuxO protein may regulate the translation process of the proteins.
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