1995 Fiscal Year Final Research Report Summary
Experimental analysis of symbiosis of Orientia tsutsugamushi and Leptorombidium.
| Project/Area Number |
06670275
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
寄生虫学(含医用動物学)
|
|---|
| Research Institution | Niigata College of Pharmacy |
|---|
Principal Investigator |
URAKAMI Hiroshi Niigata College of Pharmacy, Associate Professor, 薬学部, 助教授 (80139732)
|
|---|
| Project Period (FY) |
1994 – 1995
|
| Keywords | Orientia tsutsugamushi / rickettsia / scrub typhus / intracellular symbiosis / Leptotrombidium / sex ratio / serotype / vertical transmission |
|---|
| Research Abstract |
We analyzed the symbiosis of Orientia tsutsugamushi and Trombiculid mite by microbiological and experimentaltechniques.
1.We developed a method to observe rickettsiae in the mites by immunofluorescent microscopy, which largely improved a laborious work to maintain rickettsia-positive colonies of Leptotrombidium.
2.Secrotype of the rickettsiae in a single mite could be analyzed by the above-mentioned method with type-specific monoclonal antibodies. It was demonstrated that each mite and each family line of the mites harbor rickettsiae of a single serotype. This is the contrary to an opinion so far claimed.
3.To know the reason why the colony of O.tsutsugamushi-harboring L.fletcheri consists only from females, unfed larvae in the colony were fed on laboratory mice which had been injected with minocycline, a rickettsiacidal antibiotic agent. The rickettsiae in the mites were successfully eliminated from the mites, and sex ratio was observed in the descendants. All the mites at the P and F1 generations were females, but males appeared and dominated at F2 through F5 generations. This suggests that the rickettsia causes female-biased sex ratio in the rickettsia-harboring colony of L.fletcheri.
4.Strains of O.tsutsugamushi isolated isolated in Japan were analyzed by monoclonal antibodies and RFLP of a gene cording the strain specific antigen protein.It was indicated that strains in each serotype of O.tsutsutgamushi could be further classified into subtypes.
|
