Ergastoplasmic paracrystalline inclusion bodies in the adipose gonadal envelope and fat body of the glow worm, Lampyris noctiluca (Insecta, Coleoptera)

The gonads of glow worm larvae are enveloped by adipose tissue which repres ents a specialized fat body. The adipose gonadal envelope, and also to a le sser extent the fat body cells, contain tubular paracrystalline inclusion b odies (PIBs). Cells of other tissues are devoid of such inclusions. The PIB s form in the cisternae of rough ER. In young larvae PIB formation is spars e, but at advanced larval stages PIBs often occur as bundles in stacks of e rgastoplasm. Typically, a PIE within a cisterna consists of four to seven p arallel tubules. The outer diameter of a tubule is ca 28.8 nm and the width of the tubule lumen ca 12.2 nm. The "wall" of a tubule contains globular p rotein subunits of ca 8.3 nm diameter; the subunits are arranged helically. Since the adipose gonadal envelope progresses through a cytological differ entiation process during differentiation and maturation of the gonads, the increased number of PIBs may indicate enhanced metabolic activity of the ti ssue related to nutrition of the growing gonads. (C) 2000 Elsevier Science Ltd. All rights reserved.