Fig. 1. Transcript levels for V-ATPase subunits from Manduca sexta during starvation. (A) Pooled total RNA from the midgut of three fifth-instar larvae (2 µg each) was separated by gel electrophoresis, transferred onto nylon membranes and hybridized with digoxigenin-labelled ssRNA probes specific for the indicated V-ATPase subunits. Labelled transcripts from starved (left) or feeding (right) larvae were visualized by chemiluminescence and autoradiography. The far left column shows molecular mass standards (in kb). (B) Pooled total RNA was dotted onto nitrocellulose and hybridized, and chemiluminescence signals were quantified densitometrically. Values (± S.E.M., N=3) are given as a percentage of signal intensities obtained from feeding larvae and are normalized to the transcript levels of ribosomal protein S7 (Jiang et al., 1996). Representative dots have been inserted in the corresponding columns with RNA from feeding larvae in the upper row and RNA from starved larvae in the lower row. A—H, subunits of the V₁ complex; a—e, subunits of the V_o complex.