Characterization of Multisugar-Binding C-Type Lectin (SpliLec) from a Bacterial-Challenged Cotton Leafworm, Spodoptera littoralis

Abstract

BackgroundVarious proteins that display carbohydrate-binding activity in a Ca2+-dependent manner are classified into the C-type lectin family. They have one or two C-type carbohydrate-recognition domains (CRDs) composed of 110–130 amino acid residues in common. C-type lectins mediate cell adhesion, non-self recognition, and immuno-protection processes in immune responses and thus play significant roles in clearance of invaders, either as cell surface receptors for microbial carbohydrates or as soluble proteins existing in tissue fluids. The lectin of Spodoptera littoralis is still uncharacterized.MethodologyA single orf encoding a deduced polypeptide consisting of an 18-residue signal peptide and a 291-residue mature peptide, termed SpliLec, was isolated from the haemolymph of the cotton leafworm, S. littoralis, after bacterial challenge using RACE-PCR. Sequence analyses of the data revealed that SpliLec consists of two CRDs. Short-form CRD1 and long-form CRD2 are stabilized by two and three highly conserved disulfide bonds, respectively. SpliLec shares homology with some dipteran lectins suggesting possible common ancestor. The purified SpliLec exhibited a 140-kDa molecular mass with a subunit molecular mass of 35 kDa. The hemagglutination assays of the SpliLec confirmed a thermally stable, multisugar-binding C-type lectin that binds different erythrocytes. The purified SpliLec agglutinated microorganisms and exhibited comparable antimicrobial activity against gram (+) and gram (−) bacteria too.ConclusionsOur results suggested an important role of the SpliLec gene in cell adhesion and non-self recognition. It may cooperate with other AMPs in clearance of invaders of Spodoptera littoralis.

Altered Gene Expression: Induction/Suppression in Leek Elicited by Iris Yellow Spot Virus Infection (IYSV) Egyptian Isolate

“…our results confirmed the importance of differential display for discovering and identifying new genes. Several studies (2,41,42) compared RnA microarray and the differential display technique and concluded that DD-PcR is a method that allows systematic comparison of expressed mRnA in the cells. They added that DD-PCR is becoming more efficient today in isolating and characterizing genes differentially expressed among cells, tissues or individuals.…”

Identification of a Novel Secretory Gland Producing C-type Lectin in the Flesh Fly (<i>Sarcophaga peregrina</i>)<i>, </i>and its Characterization

“…CLEM 20 and 36 were shown to be members of C-type lectins (Yamamoto-Kihara & Kotani 2004, Yamamoto-Kihara et al 2011), a group demonstrated to be involved in the self-defense system against pathogenic agents (Natori et al 1999, Yu & Kanost 2003, Tanji et al 2008, Seufi et al 2012. In our preliminary experiments, the extract of CLPT containing the CLEMs was found to be involved in suppression of E. coli growth (our unpublished data).…”

Identification and Phylogenetic Analyses of Two Isoforms of the Antibacterial Gene Diptericin from the Larval Tissue of Musca domestica (Diptera: Muscidae)

“…Many studies have described the enhancement of the insect immune system and induction of AMPs due to stress and/or bacterial challenge (26)(27)(28)(29)(30)(31)(32)(33). Elution and sequencing of the induced bands were performed and the generated sequences were blasted to defensin, diptericin, and attacin sequences.…”