Feeding habits of the darkfin hind Cephalopholis urodeta (Serranidae) at Iriomote Island, southern Japan

ABSTRACT: The feeding habits of the serranid fish Cephalopholis urodeta were examined on the basis of 204 adult specimens collected from coral reef areas at Iriomote Island, Ryukyu Islands, Japan. Sampling was conducted in November 1997 and February, May, and August 1998. Among the specimens, 95 (46.6%) had empty stomachs, the mean Stomach Fullness Index of the specimens overall being extremely low (0.6). Over a 1-year period, the most important prey of this species were small fishes and decapod crustaceans, the two categories together constituting 73.4% of stomach contents by weight. However, seasonal differences in basic dietary composition were apparent. Fishes were abundant in the diet in May and November, whereas the proportion of hermit crabs in the diet was higher in February compared to other months.     

Nebulin and N-WASP cooperate to cause IGF-1-induced sarcomeric actin filament formation

Insulin-like growth factor 1 (IGF-1) induces skeletal muscle maturation and enlargement (hypertrophy). These responses require protein synthesis and myofibril formation (myofibrillogenesis). However, the signaling mechanisms of myofibrillogenesis remain obscure. We found that IGF-1-induced phosphatidylinositol 3-kinase-Akt signaling formed a complex of nebulin and N-WASP at the Z bands of myofibrils by interfering with glycogen synthase kinase-3β in mice. Although N-WASP is known to be an activator of the Arp2/3 complex to form branched actin filaments, the nebulin-N-WASP complex caused actin nucleation for unbranched actin filament formation from the Z bands without the Arp2/3 complex. Furthermore, N-WASP was required for IGF-1-induced muscle hypertrophy. These findings present the mechanisms of IGF-1-induced actin filament formation in myofibrillogenesis required for muscle maturation and hypertrophy and a mechanism of actin nucleation.     

Analysis by numerical experiments of desalinization of a salt-affected paddy field using a rice husk underdrainage system

Paddy and Water Environment - In a monsoon climate, salt accumulates not only in drylands, but also in paddy fields during the dry season. Because natural desalinization by gravitational drainage...