| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2005: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 2004: ¥2,100,000 (Direct Cost: ¥2,100,000)
|
|---|
| Research Abstract |
An in vitro culture technique for Cryptocaryon irritans, the causative agent of white spot disease of marine fishes, was developed. A medium consisting of a fish culture cell layer and an agarose gel layer (Leibovit's L-15, 100 um/ml penicillin, 100iu/m1 streptomycin, 10% fetal calf serum, 0.22% agarose) was developed and used for culture. Thereonts, the infective stage of the parasite, grew to ca. 200 urn long in the media for 4 days, when inserted between the layers, although the parasites gradually decreased in number in the medium. Parasites grown in the medium accomplished normal development when transferred into seawater ; they were encysted, performed cell fissions and released infective theronts. This is the first case, in which the parasite completed its life cycle without host fish.
When black mollies were challenged with theronts produced with the above culture technique, 40% of parasites were recovered from the fish ; the recovery rate was comparable to previously reported recovery rates in therents generated using fish host. This indicated that the parasites produced in vitro had infecting ability comparable to those produced in vivo.
By using the in vitro culture technique, C. irritans was grown well. However, host fish is still necessary to obtain theronts for the culture. A technique for repeatedly complete the life cycle without host fishes is needed for future developments of vaccines and chemotherapies for the disease.
|
