Molecular Characterization of Mosquitocidal Toxin (Surface Layer Protein, SLP) from Bacillus cereus VCRC B540
A marine Bacillus cereus (VCRC B540) with mosquitocidal effect was recently reported from red snapper fish (Lutjanus sanguineous) gut and surface layer protein (S-layer protein, SLP) was reported to be mosquito larvicidal factor. In this present study, the gene encoding the surface layer protein was amplified from the genomic DNA and functionally characterized. Amplification of SLP-encoding gene revealed 1,518 bp PCR product, and analysis of the sequence revealed the presence of 1482 bp open reading frame with coding capacity for a polypeptide of 493 amino acids. Phylogenetic analysis revealed with homology among closely related Bacillus cereus groups of organisms as well as Bacillus strains. Removal of nucleotides encoding signaling peptide revealed the functional cloning fragment of length 1398 bp. Theoretical molecular weight (51.7 kDa) and isoelectric point (5.99) of the deduced functional SLP protein were predicted using ProtParam. The amplified PCR product was cloned into a plasmid vector (pGEM-T), and the open reading frame free off signaling peptide was subsequently cloned inpET-28a(+) and expressed in Escherichia coli BL21 (DE3). The isopropyl-β-D-thiogalactopyranoside (IPTG)-induced recombinant SLP was confirmed using western blotting, and functional SLP revealed mosquito larvicidal property. Therefore, the major findings revealed that SLP is a factor responsible for mosquitocidal activity, and the molecular characterization of this toxin was extensively studied.
KeywordsSurface layer protein B. cereus Cloning Mosquito L. sanguineus Phylogenetic
The first author acknowledges the Pondicherry Central University for providing the student fellowship for registering his PhD program. The authors acknowledge Dr. P. Jambulingam, the Director of VCRC, Pondicherry-605006, for the permission to undertake DST-overseas fellowship. The authors thank to Department of Science and Technology (DST), Ministry of Science and Technology of Government of India and National Research Foundation of Korea (NRF) and Ministry of Science, and ICT and Future Planning of the Republic of Korea under sanction order INT/ROK/IKRI-09/2014 dated on January 01, 2015.
Compliance with Ethical Standards
This article does not contain any studies with animals performed by any of the authors.
Conflict of Interest
The author declares that he has no conflict of interest.
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