Hemolymph proteins were analyzed quantitatively and qualitatively throughout the larval development of Bombyx mori. The hemolymph protein concentration decreased by the 4th larval instar, with cyclic increases until molting and decreases after ecdysis. The protein concentration increased rapidly after the 4th molt and reached a maximum value at the end of the 5th instar, with female larvae showing higher concentration than the male ones. This sexual dimorphism was obtained only after day 2 of the 5th instar. The electrophoretic analysis of hemolymph proteins revealed the existence of two groups of major proteins from hatching to the 3rd larval instar. Their content decreased gradually in the 4th instar and they disappeared in the 5th instar. The two groups should be referred to as “Proteins of young larvae -A and -B (PYL-A and PYL-B)”. PYL-A and PYL-B consisted of four and three proteins, respectively. In the late 5th instar, hemolymph proteins consisted of 3 major proteins (SP-2, 30kDa proteins and FL-1 with the latter being minor in the male) and many minor ones. These results clearly indicated that characteristics of the hemolymph at the young larval stage (1st instar to 3rd instar) were very different from those of the 5th instar in terms of the major protein and total protein concentrations.
All Science Journal Classification (ASJC) codes
- Polymers and Plastics