A serine protease‐associated lectin in the cytolytic system of blowfly (Chrysomya megacephala) larvae: Evidence and characterization

Abstract

Cytolytic activity against invading microorganisms is one of the innate forms of immunity in invertebrates. A serine proteaseassociated sialic acid-specific cytolytic lectin was purified using glutaraldehyde-fixed ox erythrocytes from the larval extract of blowfly (Chrysomya megacephala). The purified lectin lysed vertebrate erythrocytes with effective haemolysis of ox red blood cells (RBCs) in an isotonic medium. The degree of haemolytic (HL) activity of the purified cytolytic lectin depended on its concentration, pH, temperature, and calcium ions. It was sensitive to ethylenediaminetetraacetic acid. The native molecular mass of the C-type lectin was 260 ± 26 kDa, comprising four different polypeptide subunits of 75 kDa (pI~8), 69 kDa (pI~7.0), 61 kDa (pI~5.3), and 55 kDa (pI~4.6). The association between the C-type lectin and serine protease was confirmed by MALDI-TOF-MS analysis that revealed its homology in the same spectral peak as well as the proteases and phenylmethylsulphonyl fluoride inhibition of HL activity. Haemolysis inhibition by N-acetylneuraminic acid and other sugars revealed the properties of the lectin. The purified lectin distorted the integrity of ox RBCs and Paenalcaligenes hermetiae. This in vitro study documents the presence of a cytolytic system in blowfly (C. megacephala) larvae for the clearance of invading microbial pathogens in their feeding niche.

RNA sequencing analysis reveals the role of choline acetyltransferase in regulating development, reproduction, and insecticide susceptibility in Tribolium castaneum (Coleoptera: Tenebrionidae)

“…In one study, sialic acid binding lectins associated with serine protease were detected in extracts from blowfly (Chrysomya megacephala) larvae. This innate immune form of invertebrates is related to the cytolysis activity of insects against invading microorganisms (Paulchamy et al 2020). Thus, serine proteases are involved in the immune response of insects to exogenous toxic substances or microorganisms.…”

“…This innate immune form of invertebrates is related to the cytolysis activity of insects against invading microorganisms (Paulchamy et al . 2020). Thus, serine proteases are involved in the immune response of insects to exogenous toxic substances or microorganisms.…”

N‐acetyl‐D ‐glucosamine‐binding lectin ( PrLec ) from the serum of healthy blue swimming crab Portunus reticulatus agglutinates Gram‐positive ( Micrococcus luteus ) and Gram‐negative ( Escherichia coli ) bacteria

“…binding lectin by Kochibe and Matta (1989). Moreover, for N-acetylglucosamine binding lectins, affinity chromatography with various strategies was ideally preferred (Rafestin et al, 1974). The molecular weight of monomeric mannose-specific lectin from P. pelagicus was 155 kDa, which is comparable to the heterodimer N-acetyl glucosamine specific lectin from P. reticulatus having the molecular weight of 166 kDa (Jayanthi et al, 2017).…”

“…It could be presumed that probable presence of hydrophobic amino acids in PrLec could play a role in disturbing the bacterial membrane integrity. Besides, cation independent lectins in invertebrates can efficiently bind the lipopolysaccharide of Gram‐negative bacteria whereas for Gram‐positive, it could be hypothesized that PrLec might have the ability to recognize peptidoglycan (Arokiyaraj et al, 2022; Arumugam et al, 2019; Paulchamy et al, 2020; Sreeramulu et al, 2018; Tamilarasan et al, 2021).…”

Immune Transcripts of the Pacific Oyster, Crassostrea gigas Larvae that Change in Expression as a Result of Bacteria Challenge

“…With the rst identi cation of a complement homolog found in the sea urchin in 1996 [60]. The recognition molecules and associated serine proteases, colins, MBL-associated serine proteases (MASPs), C1q1, CaC1q2, C3 and C2/Complement factor B (Bf) and C1q-domain containing protein have been recently reported in invertebrates [61][62][63][64][65][66]. In innate immunity, C1q-domain containing proteins can be considered as specialized PRPs because they have the ability to bind pathogens directly through PAMPs and to trigger phagocytosis [67].…”