H. Akai et al., ULTRASTRUCTURE OF POSTERIOR SILK GLAND-CELLS AND LIQUID SILK IN INDIAN TASAR SILKWORM, ANTHERAEA-MYLITTA DRURY (LEPIDOPTERA, SATURNIIDAE), International journal of insect morphology & embryology, 22(5), 1993, pp. 497-506
The ultrastructural characteristics of the posterior silk glands of th
e mature Antheraea mylitta (Lepidoptera : Saturniidae) larvae were cla
rified. Fibroin globules containing a small dense mass of fibroin fibe
rs are produced in Golgi vacuoles, and released from the apical surfac
e into the lumen by exocytosis. Bundles of microfilaments, which serve
as a dynamic skeleton, are well developed. Numerous autophagosomes or
iginating from mitochondria accumulate in both basal and apical ends o
f the gland cell; the degenerated materials are released in the baseme
nt membrane and into the gland lumen, respectively. These materials in
vade the central fibroin column, leaving digested vacuoles in the fibr
oin cocoon filament. Ours may be the first finding of this rare phenom
enon in which the degenerated lysosomes originated from mitochondria i
n both liquid silk in the lumen and cocoon filament.