抄録
Developmental changes in the fine structure of the posterior silk gland cells were studied with a recessive mutant of Bombyx mori named flimsy cocoon (flc) whose cocoon-shell weight is much less than that of the normal strain of B. mori. The flc posterior silk gland develops normally until 60 h after the fourth ecdysis. By the 72nd hour, unusual numbers of globules, which we have called as fibroin globules, begin to accumulate in the apical cytoplasm of the mutant cell. These globules increase in number until the 96th hour, when they fill most of the apical cytoplasm and extend into the basal region. In the normal cell at the corresponding stages, massive amounts of fibroin are synthesized and secreted rapidly with no storage of fibroin globules.
