Receptor‐mediated endocytosis of lipid and lipophorin by the larval fat body, adult ovary and testis in the wax moth Galleria mellonella

Abstract

Lipophorin (Lp) in the hemolymph of insects is known to selectively deliver lipids from sites of absorption or synthesis to sites of storage and utilization, such as the fat body, ovary and testis; however, no study regarding this has been reported in Galleria mellonella. In the present study, we examined the process by which Lp is taken up into the larval fat body, adult ovary and adult testis, and the transfer of lipid by Lp to these tissues in Galleria mellonella. To investigate the involvement of a receptor in Lp endocytosis, the larval fat body, adult ovary and adult testis were incubated for 1 h at room temperature with fluorescein isothiocyanate (FITC)-Lp, FITC-Lp plus unlabeled Lp, and FITC-Lp plus suramin, a receptor endocytic inhibitor. The amounts of FITC-Lp in the three tissues were significantly decreased in the presence of unlabeled Lp and suramin, indicating that endocytosis of Lp by the tissues is mediated by a receptor. To examine the transfer of lipid by Lp, the tissues were incubated for 1 h at room temperature with 1,1′-dilinoleyl-3,3,3′,3′tetramethylindocarbocyanine perchlorate (DiI)-Lp, DiI-Lp plus unlabeled Lp, and DiI-Lp plus suramin. The transfer of lipid by Lp was inhibited in the presence of unlabeled Lp and suramin, which is consistent with a receptor-mediated process. Our results show that the transfer process of lipid by Lp and uptake of Lp itself is by receptor-mediated endocytosis.

Anatomy of male and female reproductive organs of stink bugs pests (Pentatomidae: Heteroptera) from soybean and rice crops

“…Lipophorin is one of the major insect lipoproteins (Van Hoof et al 2005), particularly involved in lipid transport from absorption or synthesis to storage and uptake, such as the fat body, ovary, and testis (Jung & Yun 2007). Differences in diet and metabolism may be related to differences in pigment color of the peritoneal sheath of the reproductive tract.…”