Proteins in the diapause eggs of Triops longicaudatus

Abstract

Triops longicaudatus, a small aquatic crustacean inhabiting the paddy fields of Japan, has eggs that can undergo diapause and survive under dry conditions for several decades. In this study, diapause eggs were embedded in resin and thin sections were observed under light microscopy. Observations revealed that there were abundant yolk granules, or many nuclei, in a diapause egg. Diapause eggs, post-diapause eggs and eggs just after oviposition were homogenized in their groups and the residual material was removed by centrifugation. The samples were analyzed for proteins using two-dimensional gel electrophoresis (2D-GE). The protein spots were visualized by silver staining, and revealed that there were more than 1,400 spots in a diapause egg, and two protein spots (26 kDa, 4.7 isoelectric point) appeared specifically in diapause eggs. It is suggested that these proteins have some relationship with long diapause. The proteins differ from a small heat-shock/α-crystallinprotein (p26) of Artemia franciscana.