A Critical Assessment of Bombyx mori Haemolymph Extract on Staphylococcus aureus an In vitro and In silico Approach

Harinatha Reddy A,Srinivasulu C

doi:10.4172/jpb.1000410

Abstract

The newly reemerging drug-resistant Gram-positive pathogens require the discovery of new drug targets and the development of new therapeutics. We focus on antimicrobial proteins which inhibits growth of Staphylococcus aureus. In the present study fifth instar Bombyx mori larvae was used and infected with S. aureus by intrahaemocoelic injection of bacterial sample. The haemolymph was collected from the healthy and infected larvae after 24 h of infection and stored at -4°C in eppendorf tubes until use. Haemolymph extract was prepared and antimicrobial activity was done by the classical well diffusion method. Haemolymph extract prepared form infected larvae exhibit maximum zone of inhibition on S. aureus when compared with healthy haemolymph extract. Bioinformatics tools were used to find out the molecular interaction and binding mode of antimicrobial peptides from B. mori such as Moricin and Cecropin on three different drug target proteins Glycerol phosphate lipoteichoic acid synthase (PDB: 2W5Q), ABC transporter (PDB: 1P99) and DNA Gyrase (PDB: 2XCO) from S. aureus. Hex Docking software was used for the docking studies. The interaction mode and binding results can be represented in terms of docking energy. The best binding energies were obtained from the docking of DNA gyrase with Moricin and Cecropin (-702.13 Kcal/mol and -639.39 Kcal/mol) respectively.

Highlights

The failure of most important drugs on microorganisms, there is an urgent need to develop and other control agents
Bioinformatics tools were used to find out the molecular interaction and binding mode of antimicrobial peptides from Bombyx mori such as Moricin and Cecropin on three different drug target proteins of S. aureus (Glycerol phosphate lipoteichoic acid synthase, ATP-Binding Cassette (ABC) transporter and DNA Gyrase)
In the present hypothesis Moricin and Cecropin bind to DNA gyrase enzyme with high binding energy and inhibits DNA gyrase activity when compared to other drug target proteins such as Glycerol phosphate lipoteichoic acid synthase and Dipeptide ABC transporter-PG110

Summary

Introduction

The failure of most important drugs on microorganisms, there is an urgent need to develop and other control agents. The objective of study is to find out antimicrobial activity of antimicrobial peptides and their interaction with drug target proteins of Staphylococcus aureus. Antimicrobial peptides are oligo peptides with a varying number of amino acids, most of them are cationic, which target bacterial cell membranes and cause disintegration of the lipid bilayer structure [2,3]. The insect antibacterial peptides are very potent in their IC50 even in the sub-micromolar or low micromolar range, majority of peptides interact with bacterial membranes [4]. Insects are one of the major sources of antimicrobial peptides/proteins. Cecropin is the first insect antimicrobial peptide has been purified from Hyalophora cecropia pupae. Insect antimicrobial peptide can be classified into four families based on their structures or unique sequences: The α-helical peptides (Cecropin and Moricin), cysteine-rich peptides (insect defensin and drosomycin), proline-rich peptides (apidaecin, drosocin, and lebocin), and glycine-rich peptides/proteins (attacin and gloverin) [5]

Methods

Discussion

Conclusion