In order to elucidate the participation of L-cysteinesulphinate decarboxylase (CSD) in taurine synthesis in Japanese¯ounder, and the synthetic ability of taurine in other ®sh species, hepatic (or hepatopancreatic) CSD activities of several ®sh species were compared. Enzyme activity was determined by measuring the production of hypotaurine during an incubation of crude enzyme preparation with L-cysteinesulphinate as a substrate. HPLC was used for the analysis of hypotaurine. The enzyme activities of ®sh were lower than those of mammals. Japanese¯ounder Paralichthys olivaceus (Temminck et Schlegel) showed half the activity of rainbow trout (Oncorhynchus mykiss Walbaum). As activity was almost constant throughout the ®sh growth cycle, CSD does not seem to be responsible for low production of taurine in juvenile Japanese¯ounder. On the other hand, CSD activity was not present in yellowtail (Seriola quinqueradiata Temminck et Schlegel), blue®n tuna Thunnus thynus (Linnaeus) or skipjack (Katsuwonus pelamis (Linnaeus)). The inability to synthesize taurine and the possible dietary requirement for taurine is suggested in these ®sh species.

This study aimed to investigate the incidence of the canine ear dermatoses caused by mites and the relativity of the causative mites of canine dermatoses to the pruritic dermatoses of the families possessing the pet dogs. Total 970 samples were collected from the lesional hairs and scales of the ear of pet dogs referred to Chung-Woon animal clinic in Seoul from January, 1990 to December, 1995. The mites were collected from the samples by means of the washing method. Presence of pruritic dermatoses in the families possessing the pet dog was evaluated. Among 2,147 mites collected from 970 samples, 2,117 specimens were Octodectes cynotis and others were Sarcoptes canis (30 mites). O. cynotis were found in 382 samples out of total 970 samples (39.4%) and S. canis were found in 3 samples (0.3%). Although two families out of 382 families that possessed the diseased pet dog by O. cynotis had the family histories of pruritic dermatoses, their pruritic dermatoses were not related to the infestation by O. cynotis. In conclusion, O. cynotis, the most common canine mite producing pruritic ear dermatoses, does not cause pruritic dermatoses in man.