| Project/Area Number |
18590437
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Bacteriology (including Mycology)
|
|---|
| Research Institution | Kyorin University |
|---|
Principal Investigator |
KAMIYA Shigeru Kyorin University, Faculty of Medicine, Professor (10177587)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
OSAKI Takako Kyorin University, Faculty of Medicine, Instructor (90255406)
HANAWA Tomoko Kyorin University, Faculty of Medicine, Instructor (80255405)
KURATA Satoshi Kyorin University, Faculty of Medicine, Instructor (00383670)
田口 晴彦 杏林大学, 医学部, 助教授 (20146541)
|
|---|
| Project Period (FY) |
2006 – 2007
|
| Project Status |
Completed (Fiscal Year 2007)
|
| Budget Amount *help |
¥4,020,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥420,000)
Fiscal Year 2007: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2006: ¥2,200,000 (Direct Cost: ¥2,200,000)
|
|---|
| Keywords | quorum sensing / probiotics / biofilm / intestinal flora / pathogenesis / クオラムセンシン |
|---|
| Research Abstract |
Quorum sensing (QS) is a system for regulation of bacterial gene by autoinducer (AI) which is produced according to bacterial density. Bacterial biofilm is associated with immunological escape, resistance to anti-microbial agents, and its formation is regulated by QS. In order to develop the probiotics which regulate bacterial quorum sensing, the effect of intestinal flora bacteria on biofilm formation by E. coil was examined.
Biofilm assay in microplate was established by using E. coll. Addition of AI-2 increased biofilm formation by E. coli in this assay. Using 16 species and 25 strains of intestinal flora bacteria, it was shown that culture supernatants of Bifidobacterium longm, Clostridium difficile, Enterococcus faecalis, Lactobacillus casei, Peptoniphilus asaccharolyticus and Veillonella parvula inhibited biofilm formation by E. coil. In contrast, culture supernatants of Bcateroides and Fusobacterium necrophorum enhanced biofilm formation. As there was no significant difference in biofilm formation between Helicobacter pylori TK1402 stain and its luxS mutant strain without AI-2 production, it was speculated that biofilm formation was not induced in IL pylori by QS.
Using 576 strains isolated from feces of healthy adults, the effects of culture supernatants of these bacteria on biofilm formation by E. coli was examined. Twelve strains inhibited the biofilm formation with less than 80 % level of control. As biofilm formation by E. coli was not effectively done, the additional experiment using 534 stains was performed. Culture supernatants of 43 and 22 strains inhibited biofilm formation by E. coli by more than 20% and 50%, respectively. Culture supernatants of 42 and 5 strains inhibited biofilm formation by S. aureus by more than 205 and 50%, respectively. Identification of these strains and the effects of these stains on the expression of QS-related genes for adhesin and bacterial toxin need to be clarified.
|
