Characteristics of the parvalbumin and the ultrastructure in the sonic muscle of the marbled rockfish, Sebasticus marmoratus

Abstract:

This anatomical, biochemical and the ultrastructural study on the sound production system in marbled rockfish Sebasticus marmoratu is focused on characteristics of the parvalbumin and the ultrastructure of the sonic muscle. The results reveal that the molecular weight of parvalbumin is about 10~14 ku in both sonic muscle and the white muscle of the fish. The TEM micrograph reveals the ultrastructural characteristics of the muscle fibers, among that the T system/SR of the sonic muscle are typically at both the Z-lines and A/I junctions, but are at the level of the Z-line only in the white muscle fibers. Sarcoplasmic reticulum and cell membranes in the sonic muscle fibers are wider and more developed than those in the white muscle. Moreover, there are more mitochondria which are crowded together in the sonic muscle cell, by contrasting, that are relatively fewer and are scattered in the white muscle cell. Our results suggest that: in marbled rockfish, the parvalbumin may not be playing an important role in the fast contraction of the sonic muscle, but the wide sarcoplasmic reticulum and enhanced cell membrane, the T system/sarcoplasmic reticulum, these ultrastructural advances may ensure the rapid contraction function of the sonic muscles for sound production. The feature of large amount of crowded mitochondria in the sonic muscle cells may enable the fish to produce the sound.