[Regulation of vesicular transport by membrane curvature]

A cellular membrane is highly deformable: during the last decade, numerous studies have dissected at the molecular scale how during vesicular transport various proteins could deform a membrane or recognize membrane deformation. We will discuss how the activity of ArfGAP1 and GMAP-210, two proteins involved in vesicular transport, is regulated by membrane curvature thanks to an ALPS motif. Since a membrane is not solely defined by its shape but also by its lipids composition, we will show how others proteins are adapted to other lipid compositions to recognize membrane shape.

Sexual differentiation traits in functional males with female genital apertures (male symbol fga) in the woodlice Armadillidium vulgare Latr. (Isopoda, Crustacea)

This study reports the results of examination of the gonadal morphology and ultrastructural features of the androgenic hormone (AH)-producing androgenic gland cells of laboratory stocks of functional male woodlice, Armadillidium vulgare, with female genital apertures ( male symbol fga), with and without experimentally induced infections of the sex-ratio-distorting endobacterial parasite, Wolbachia. Males ( male symbol fga) have been reported in wild populations containing individuals infected with this maternally transmitted sex-ratio-distorting parasite. We report a reduction of testicular segment (utricle) number, androgenic gland cell hypertrophy, and electron-dense ultrastructural cytological features in male symbol fga males. The presence of the Wolbachia parasite had no effect on the features we examined. These results suggest that male symbol fga males are produced as the result of a delayed expression/action of the male sex-determining AH which causes a "lag-phase" delay in male differentiation in genetic males and is not due to the presence, in genetic females, of a hypothetical, epigenetic "M" gene as suggested by Rigaud and Juchault. Our results favor the interpretation of males as true genetic (ZZ) males in which the delayed AH action appears to involve cellular AH trafficking pathways which may be controlled by an impaired autosomal gene responsible for AH action.