魚貝類の石灰化に関する研究-VII

Abstract

The protein concentration and distribution of the protein fractions of the otolith fluid (endolymph of the sacculus) were determined seasonally by the micro-Kjeldahl method and by paper and cellulose acetate electrophoresis, using three types of fish, flatfish, goldfish and rainbow trout, which have differing otolith characteristics. (1) The otolith fluid was successfully collected from the sacculus by use of a fine glass capillary. The average amount of this fluid collected from one medium-sized individual was about 15 μl in flatfish, 1 μl in goldfish, and 7 μl in rainbow trout. (2) An additional fraction of prealbumin was found to occur seasonally in the otolith fluid of both flatfish and goldfish at a certain time corresponding to the period of opaque zone formation in their otoliths, while such a seasonal occurrence of a prealbumin fraction was not detected electrophoretically throughout the year in the otolith fluid of rainbow trout whose otolith is homogeneously glassy, nor in all the sera of the species examined. (3) In the otolith fluid of flatfish, the protein concentration was found to increase seasonally corresponding to the period of opaque zone formation in the otolith, while such a seasonal change of the protein concentration was not found in the otolith fluid of rainbow trout, nor in the sera of both flatfish and rainbow trout. (4) Accordingly, both the seasonal occurrence of an additional prealbumin fraction and the seasonal increase of the protein concentration in the otolith fluid may favor the formation of the organic matrix of the opaque zone in the otolith.