Antibacterial effect and cytotoxicity of beta-1,3-1, 4-glucanase from endophytic Bacillus subtilis SWB8

We studied the antibiotic activity and selective cytotoxicity of beta-1,3-1,4-glucanase from endophytic Bacillus subtilis SWB8.

Based on gel permeation chromatography, sodium dodecyl sulfate-polyacrylamide gel electrophoresis and liquid chromatography-tandem mass spectrometry methods, protein fragments of beta-1,3-1,4-glucanase from endophytic Bacillus subtilis strain SWB8 were purified and identified. Then, beta-1,3-1,4-glucanase was used to evaluate the antimicrobial activity against Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis, Escherichia coli, Salmonella typhi, Salmonella paratyphi A, Shigella dysenteriae, Candida albicans and Cryptococcus neoformans and cytotoxicity against human pulmonary adenocarcinoma cells (A549) and human bone marrow mesenchymal stem cells (MSCs) by using the disc diffusion, methyl thiazolyl tetrazolium and flow cytometry methods, respectively.

Bacterial beta-1,3-1,4-glucanase showed broad antimicrobial spectrum against all nine bacterial and fungal strains. Furthermore, beta-1,3-1,4-glucanase possessed significant anticancer activity against A549 cells that the IC50 and IC90 values were 11.5 and 20.1 microg/mL, respectively. The percentage of apoptotic A549 cells treated with different concentrations of beta-1,3-1,4-glucanase was significantly increased from 4.43% of the control to 43.1% of 19.2 microg/mL glucanase in a dose dependent manner. In contrast, these changes could not be observed in human bone marrow mesenchymal stem cells.

Beta-1,3-1,4-glucanase could be a potential source of desirable antimicrobial agent, or anticancer compounds with higher efficiency and lower toxicity.