2007 Fiscal Year Final Research Report Summary
Isolation of hardly cultivable bacteria from gastro-intestinal tract of herbivores and evaluation of their functions
| Project/Area Number |
17380157
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Zootechnical science/Grassland science
|
|---|
| Research Institution | Hokkaido University |
|---|
Principal Investigator |
KOBAYASHI Yasuo Hokkaido University, Res. Fac. Agriculture, Professor (50153648)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
TAKENAKA Akio Nati. on. Agr. Food Res. Org., N.I.L.G.S., Team Leader (40155031)
MITSUMORI Makoto Nati. on. Agr. Food Res. Org., N.I.L.G.S., Researcher (40418588)
TAJIMA Kiyoshi Nati. on. Agr. Food Res. Org., N.I.L.G.S., Researcher (80343953)
MATSUI Hiroki Mie University, Grad School of Bioresources, Associate Professor (30346001)
|
|---|
| Project Period (FY) |
2005 – 2007
|
| Keywords | Herbivores / Gastro-intestinal bacteria / Rumen / Uncultured / Isolation and cultivation / Large intestine / Physiology and ecology / Possessing enzyme |
|---|
| Research Abstract |
The present study was performed to clarify physiology and ecology of so-far-uncultured bacteria in the gastro-intestinal tract of herbivores by means of isolation and cultivation. The bovine and ovine rumens were focused in investigation of uncultured bacteria whose presence has been recognized only by DNA based approaches. The large intestinal contents of horses and ostriches were also employed in characterization of inhabiting microbes.
The uncultured bacterial group U2 was shown by a newly developed FISH protocol to be heavily associated with grass stems in the rumen and successfully enriched on the stem by using nylon bag suspension technique. Bacteria belonging to U2 were further successfully enriched in a liquid medium supplemented with anti-Gram negative agent. The roll tube isolation was repeated in combination with PCR screening to finally obtain two strains belonging to U2 from more than 200 isolates. These two strains possessed high ability in attachment to fibrous materials.
… More
They could grow on soluble carbohydrates, exhibiting cellobiohydrolase, xylanase and arabinofuranosidase activity but not cellulose activity. These results suggest that the two strains of U2 contribute to consumption of cellulose hydrolysis products and hemicellulose degradation, especially cleavage of arabinose side chain of hemicellulose.
By phylogenetic analyses of large intestinal bacteria of horses and ostriches, presence of many uncultured bacteria was indicated. Most of them were in close relation to known fibrolytic species such as ruminococci. Japanese native horses possessed novel bacterial clusters specific to this breed that might be responsible for superiority of the native horses in fiber digestion. Also, the native horses had many large-sized fibrolytic protozoa in their large intestine that were rarely seen in other horse breed. All the above findings clearly indicate phylogenetical and ecological diversity of gastro-intestinal micorbiota of herbivores and stress that further study is obviously necessary to understand the fibrolytic system of such animals. Less
|
