Characterization of the molecular features and expression patterns of two serine proteases in Hermetia illucens (Diptera: Stratiomyidae) larvae

Abstract

To investigate the molecular scavenging capabilities of the larvae of Hermetia illucens, two serine proteases (SPs) were cloned and characterized. Multiple sequence alignments and phylogenetic tree analysis of the deduced amino acid sequences of Hi-SP1 and Hi-SP2 were suggested that Hi-SP1 may be a chymotrypsin-and Hi-SP2 may be a trypsin-like protease. Hi-SP1 and Hi-SP2 3-D homology models revealed that a catalytic triad, three disulfide bonds, and a substrate-binding pocket were highly conserved, as would be expected of a SP. E. coli expressed Hi-SP1 and Hi-SP2 showed chymotrypsin or trypsin activities, respectively. Hi-SP2 mRNAs were consistently expressed during larval development. In contrast, the expression of Hi-SP1 mRNA fluctuated between feeding and molting stages and disappeared at the pupal stages. These expression pattern differences suggest that Hi-SP1 may be a larval specific chymotrypsin-like protease involved with food digestion, while Hi-SP2 may be a trypsin-like protease with diverse functions at different stages. [BMB reports 2011; 44(6): 387-392]

Dietary and phylogenetic correlates of digestive trypsin activity in insect pests

“…The following examples confirm that trypsin structure depends more on phylogeny than feeding habit. Trypsin sequences of the scavenger dipteran Hermetia illucens L. (Kim et al., ) and the phytophagous dipteran Mayetiola destructor Say (Mittapalli et al., ; Chen et al., ) are similar to some trypsins from several species of hematophagous Diptera. Two keratin‐feeding insects, Tineola bisselliella (Hummel) (Lepidoptera) and Trox spec.…”

“…Discontinuous feeders ingest food in discrete meals, necessitating more complex regulatory mechanisms. In continuous feeders, such as phytophagous Lepidoptera (Broadway & Duffey, 1986;Toprak et al, 2010), Orthoptera (Woodring et al, 2007(Woodring et al, , 2009Van Hoef et al, 2011;Weidlich, 2013), and Coleoptera (Marshall et al, 2008), scavenger and necrophagous Diptera (Kim et al, 2011;Rivers et al, 2014), hematophagous Phthiraptera (Waniek et al, 2005), and omnivorous Dictyoptera (Sakai et al, 2006), there is a basal level of secretion of trypsin and other digestive enzymes in unfed insects. Maintenance of a basal level of proteinases is an advantage and increases the efficiency of digestion when food is abundant but nutritionally poor.…”

“…Maintenance of a basal level of proteinases is an advantage and increases the efficiency of digestion when food is abundant but nutritionally poor. In scavenger H. illucens (Kim et al, 2011) and phytophagous Costelytra zealandica (White) (Marshall et al, 2008), trypsin expression remains unchanged even after several weeks of starvation.…”

Recombinant Expression and Enzyme Activity of Chymotrypsin-like Protease from Black Soldier Fly, Hermetia illucens (Diptera: Stratiomyidae)

“…In insects, the most abundant and best studied group of SPs contains those expressed in the larval midgut, which are thought to be involved in the digestion of dietary protein (Herrero et al, 2005). The black soldier fly (BSF), Hermetia illucens, belongs to the polyphagous insect group (Kim et al, 2011). These flies can devour large amounts of garbage and food scraps in just a few hours, converting the waste into organic material that can be used as fertilizer (Diener et al, 2009).…”

“…The full-length cDNA of H. illucens chymotrypsin-like protease (Hi-SP1) is 895 bp with an open reading frame of 804 bp. The Hi-SP1 cDNA encodes a polypeptide of 267 amino acids (aa), consisting of a 16-aa signal peptide and a trypsin domain (34-263 aa) (Kim et al, 2011).…”