TRYPSIN AND AMINOPEPTIDASE GENE-EXPRESSION IS AFFECTED BY AGE AND FOOD COMPOSITION IN ANOPHELES-GAMBIAE

The effects of age and food composition on the expression of trypsin a nd aminopeptidase genes in the Anopheles gambiae gut were investigated , No trypsin mRNA was detected in the gut of newly eclosed females, bu t this mRNA accumulated to relatively high levels within the first day of life. In contrast, low, but significant trypsin enzyme activity wa s observed in newly eclosed females, Subcellular fractionation experim ents suggested that abdominal distention induces the secretion of the enzyme into the lumen, Blood, but not a protein-free meal, induced the accumulation of new trypsin mRNA and enzyme, Unlike trypsin, substant ial aminopeptidase activity was detected in newly eclosed and in older , sugar fed mosquitoes, Moreover, the subcellular localization of amin opeptidase did not change appreciably with food ingestion, and the ear ly increase of enzyme activity was independent of food composition. Co pyright (C) 1996 Elsevier Science Ltd.