Antibacterial and antitumor activity of Bogorol B-JX isolated from Brevibacillus laterosporus JX-5

Antimicrobial peptides are promising anti-infective agent candidates because they have a broad antimicrobial spectrum and bioactivity and are unlikely to elicit antibiotic resistance. The bogorols represent a new cationic antibiotic peptide and possess great therapeutic potential because of their bioactivity and precise mode of action. Here, we report that Bogorol B-JX (BBJX), a peptide previously isolated from Brevibacillus laterosporus JX-5 by us, has significant antibacterial and antitumor activities in vitro. BBJX was found to inhibit methicillin-resistant Staphylococcus aureus (MRSA) at 2.5 µg/mL with distinct mechanisms of action from those against Bacillus bombyseptieus and Escherichia coli . It penetrates MRSA membrane with little visible destruction and binds to genomic DNA. BBJX could inhibit the proliferation of human histiocytic lymphoma cell line U-937 and ConA-activated spleen cells at 5 µg/mL, but was not cytotoxic to the Jurkat cells, resting spleen cells or differentiated macrophage-like U-937 immunocytes. Moreover, BBJX caused apoptosis of U-937 cells by opening the mitochondrial permeability transition pore and stimulating the production of reactive oxygen species. Taken together, these studies provided basis for future medical application of the bogorols.