Male moths discriminate conspecific female-emitted sex pheromones. Although the chemical components of sex pheromones have been identified in more than 500 moth species, only three components in Bombyx mori and Heliothis virescens have had their receptors identified. Here we report the identification of receptors for the main sex-pheromone components in three moth species, Plutella xylostella, Mythimna separata and Diaphania indica. We cloned putative sex-pheromone receptor genes PxOR1, MsOR1 and DiOR1 from P. xylostella, M. separata and D. indica, respectively. Each of the three genes was exclusively expressed with an Or83b orthologous gene in male olfactory receptor neurons (ORNs) that are surrounded by supporting cells expressing pheromone-binding-protein (PBP) genes. By two-electrode voltage-clamp recording, we tested the ligand specificity of Xenopus oocytes co-expressing PxOR1, MsOR1 or DiOR1 with an OR83b family protein. Among the seven sex-pheromone components of the three moth species, the oocytes dose-dependently responded only to the main sex-pheromone component of the corresponding moth species. In our study, PBPs were not essential for ligand specificity of the receptors. On the phylogenetic tree of insect olfactory receptors, the six sex-pheromone receptors identified in the present and previous studies are grouped in the same subfamily but have no relation with the taxonomy of moths. It is most likely that sex-pheromone receptors have randomly evolved from ancestral sex-pheromone receptors before the speciation of moths and that their ligand specificity was modified by mutations of local amino acid sequences after speciation.

Type V collagen became solubilized in softened sardine muscle after 1 day of chilled storage with the concomitant weakening of pericellular connective tissue induced by disintegration of thin collagen fibrils. However, no significant changes were observed in the structure of interstitial connective tissue or biochemical properties of type I collagen. Z disk in myofibrils showed structural changes, but no significant loss of longitudinal continuity of myofibrils was observed even at the deteriorated Z disk from the muscle destroyed by compression test. On the other hand, tiger puffer muscle did not show significant softening during the storage, with no significant changes in structure of connective tissues and biochemical properties of collagens. These facts suggest that degradation of type V collagen causes disintegration of the thin collagen fibrils in pericellular connective tissue, weakening pericellular connective tissue and resulting in postharvest softening. Keywords: Collagen; postharvest storage; fish; connective tissue; muscle; collagen V

In order to identify free amino acids (FAA) that are importantas intracellular osmolytes in Crassostrea gigas, we investigatedthe change in FAA content in the mantle exposed to an abrupt decreaseor increase in salinity. In hypo‐osmotic adaptation, most FAA showedremarkable and synchronous decreases from 2 to 8 h, suggestingthat the non‐selective efflux of FAA was mainly responsible forthe decrease in FAA. Taurine that accounted for approximately 80% oftotal FAA content contributed most significantly to the hypo‐osmoticadaptation. In hyper‐osmotic adaptation, significant increases inglycine, alanine, β‐alanine, proline, arginine and taurinewere observed. Of these, alanine showed an immediate increase thatis important to short‐term adaptation to hyper‐osmolality, whiletaurine showed a slower and substantial increase that contributesto a long‐term adaptation to hyper‐osmolality.

A histological study combined with a newly devised compression test was