Expression of active trypsin-like serine peptidases in the midgut of sugar-feeding female Anopheles aquasalis

Abstract

BackgroundAnopheles aquasalis is a dipteran of the family Culicidae that is widely distributed in the coastal regions of South and Central America. This species acts as a vector of Plasmodium vivax, an important etiological agent of malaria, which represents a serious public health problem. In mosquitoes, trypsin-like serine proteases are important in blood meal digestion, immune responses and reproductive functions. The study of peptidases expressed in the mosquito midgut is essential to understanding the mechanisms of parasite-host interaction and the physiological process of nutrient digestion.MethodsOur study aimed to identify and characterize the proteolytic activities in the midgut of sugar-fed An. aquasalis females using zymographic analyses (substrate-SDS-PAGE), in-solution assays and mass spectrometry.ResultsHere, we used a zymographic analysis to further biochemically characterize the proteolytic profile of the midgut of sugar-feeding An. aquasalis females. The trypsin peptidases migrated between ~17 and ~76 kDa and displayed higher proteolytic activities between pH 7.5 and 10 and at temperatures between 37 °C and 50 °C. Four putative trypsin-like serine peptidases were identified using mass spectrometry and data mining. The molecular masses of these peptidases were similar to those observed using zymography, which suggested that these peptidases could be responsible for some of the observed proteolytic bands.ConclusionsTaken together, our results contribute to the gene annotation of the unknown genome of this species, to the tissue location of these peptidases, and to the functional prediction of these crucial enzymes, which all impact further studies of this species.

In-depth characterization of trypsin-like serine peptidases in the midgut of the sugar fed Culex quinquefasciatus

“…albopictus females fed on sugar express active forms of trypsin [ 53 ]. The presence of active trypsin peptidases in sugar fed females of other mosquito species has been reported [ 20 , 68 , 69 ]. Several hematophagous diptera express a series of constitutive and blood meal-induced trypsin genes in the gut [ 16 , 20 , 22 , 54 ].…”

Proteases of haematophagous arthropod vectors are involved in blood-feeding, yolk formation and immunity - a review

“…Trypsin-like SPs activities have also been observed in An. aquasalis females [ 143 ]. In the Aedes [ 144 ] and Anopheles [ 145 ] these proteases share an acidic isoelectric point, but differ in size.…”

Artificial Diets for Mosquitoes

“…Vertebrate blood is rich in proteins that are digested, in the mosquito midgut, by trypsin-proteases into their constituent amino acids [37,38,39,40]. Free amino acids are transported out of the midgut and taken up by the fat body and other tissues via specialized amino acid transporters, where specific signaling pathways in these tissues are subsequently activated [41,42,43,44,45].…”