| Project/Area Number |
14570237
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Bacteriology (including Mycology)
|
|---|
| Research Institution | OKAYAMA UNIVERSITY |
|---|
Principal Investigator |
OKAMOTO Keinosuke Okayama University, Faculty of Pharmaceutical Sciences, Professor, 薬学部, 教授 (70131183)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
NOMURA Tomohiko Tokushima Bunri University, Faculty of Pharmaceutical Sciences, Research Associate, 薬学部, 助手 (00289315)
YAMANAKA Hiroyasu Tokushima Bunri University, Faculty of Pharmaceutical Sciences, Associate Professor, 薬学部, 助教授 (30202386)
SHINODA Sumio Okayama University, Faculty of Pharmaceutical Sciences, Professor, 薬学部, 教授 (50029782)
KOBAYASHI Sagae Okayama University, Faculty of Pharmaceutical Sciences, Associate Professor, 薬学部, 助教授 (90212654)
NEGISHI Tomoe Okayama University, Faculty of Pharmaceutical Sciences, Associate Professor, 薬学部, 助教授 (80116491)
|
|---|
| Project Period (FY) |
2002 – 2003
|
| Project Status |
Completed (Fiscal Year 2003)
|
| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2003: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2002: ¥2,200,000 (Direct Cost: ¥2,200,000)
|
|---|
| Keywords | Enterotoxin / Escherichia coli / Aeromonas spp. / Secretion / Maturation / Membrane protein / Hemolysin / Diarrhea / 成熟化 / 毒素 / 細胞膜 / 蛋白分解酵素 / 菌体外毒素 / 膜 / グラム陰性菌 / プロテアーゼ |
|---|
| Research Abstract |
Diarrhea caused by the infection of bacteria is usually induced, by the action of the enterotoxin released from the bacteria into outside of the bacteria. It means that the diarrhea is not induced by the bacteria which can not secrete the active toxin into the outside of the cell, even if the bacteria synthesized the toxin in cell. In order to emerge outside of the cell as the active toxin, the toxin synthesized in cell must cross two membranes and form active structure during the secretion. Without this event, the bacteria can not express the toxic activity. We investigated the event in the productions of heat-stable enterotoxin (ST) of Escherichia coli, and enterotoxin of Aeromonas spp. It becomes clear that ST crosses the outer membrane though the pore formed by ToIC and that both Leu-412 and Leu-3 play an important role in the transportation of ST. This suggests that the compound attaching these two residues might interfere the secretion of ST, resulting the suppression of the toxicity of the bacteria producing ST. Subsequently, we found that the enterotoxin of Aeromas spp. possesses hemolytic activity, too. Then, we examined the hemolytic activity of the isolates from patients. Some of strains did not show hemolytic activity but showed enterotoxic activity. To clear the relationship between two activities, we cloned the gene encoding the new hemolysin. The results showed that there are differences in the DNA sequence between the wild type hemolysin gene and the new hemolysin gene in the amino terminal region. Furthermore, we found the protease is involved in the maturation of the hemolysin and that the protease function in cell to survive the bacteria in severe conditions, too.
|
