PROTEOLYTIC-ENZYMES OF FEMALE ANOPHELES - BIPHASIC SYNTHESIS, REGULATION, AND MULTIPLE FEEDING

Two types of trypsin activity were detected in Anopheles albimanus, a constitutive and an inductive component, which have identical immunopa tterns. The constitutive trypsin in synthesized shortly after eclosion and is retained in the midgut epithelial cells. The inductive trypsin is synthesized and released continuously after a blood meal has been ingested; maximal activities vary between 12 h and 18 h after a blood meal. Once digestion is completed, trypsin is excreted, but the consti tutive trypsin level is restored within 24 h, before the next blood me al is taken. In A. gambiae, A. stephensi, and A. quadrimaculatus, the constitutive trypsin component is also present, but at much lower leve ls. In A. albimanus fed multiple blood meals al 24 h intervals, trypsi n oscillates at nearly maximal levels as long as blood is present in t he midgut and depending on the ovarian status. Expression of the two t rypsin components in A. albimanus was found to be independent of the n eurosecretory system, but synthesis of the constitutive trypsin appear s to require the presence of the corpora allata. In all species tested , chymotrypsin is secreted after a blood meal in a similar temporal pa ttern as trypsin, but it is never present before the blood meal. Reinv estigating several aedine species for the presence of chymotrypsin by using different substrates revealed measurable quantities in blood-fed females compared to earlier reports. Equally, aminopeptidase activity is present in all species tested and characterized by a constitutive component. Its activities follow different temporal patterns than the endopeptidases. (C) 1995 Wiley-Liss, Inc.