Chymotrypsin inhibitors in mosquitoes: Activity profile during development and after blood feeding

Abstract

Chymotrypsin and trypsin inhibitors persist throughout all developmental instars of Aedes aegypti. After a blood meal, inhibitor activity against chymotrypsin was more than double that of sugar‐fed females, but only weak activity was detected in midguts where proteinase inhibitors has been thought to regulate proteinases during blood digestion. A fourfold increase in the ratio of abdominal/thoracic inhibitor activity after the blood meal strongly suggested that fat body, or other abdominal tissues, represent the major source of inhibitor. Chymotrypsin inhibitor activity was deposited in maturing oocytes. Similar results were obtained with blood‐fed Anopheles albimanus. Chymotrypsin inhibitor was active against different mosquito proteinases and against bovine α‐chymotrypsin and trypsin, but not against subtilisin, pancreatic elastase, or fungal proteases; chymotrypsin inhibitors did not interfere with bacterial growth. The hypothesis on the regulation of blood digestion through the action of proteinase inhibitors during the gonotrophic cycle was abandoned and its involvement in the phenoloxidase cascade in the mosquito egg chorion is suggested instead. Arch. Insect Biochem. Physiol. 36:315–333, 1997. © 1997 Wiley‐Liss, Inc.

Molecular characterization of genes encoding trypsin-like enzymes from Aedes aegypti larvae and identification of digestive enzymes

“…This data suggested the possible role of AaTI as an endogenous controller of digestive enzymes in larvae, since both are expressed during the larval development. Our data corroborated the results of Horler and Briegel (1997) that the trypsin activity was higher in midgut homogenates than in whole larvae, suggesting the presence of trypsin inhibitors in larval tissues. Moreover, AaTI presents a strong inhibitory activity for larval trypsins in the range of pM, though in adults it acts as a thrombin inhibitor, since it has a dual activity.…”

Gene expression patterns associated with blood-feeding in the malaria mosquito Anopheles gambiae

“…Acquisition of a blood meal stimulates midgut proteolytic activity such that approximately 80% of the protein content is digested within one day [10-14]. Serine proteases including trypsins and chymotrypsins are responsible for the majority of endoproteolytic activity [11,12,15]. The role of trypsins in blood digestion has been well documented in Aedes aegypti , and more recently it has been investigated in An.…”

Cloning and characterization of protease inhibitor‐like cDNAs from the Hessian fly mayetiola destructor (SAY)

“…Proteinase inhibitors are involved in the regulation of insect development. For example, in mosquitoes inhibitors of chymotrypsin are known to regulate the development of the insect (Horler & Briegel, 1997). In Drosophila, the inhibitor gene kil‐1 is expressed during prepupal stage (Kress et al ., 2004).…”