Identification and characterization of a novel circular bacteriocin, bacicyclicin XIN-1, from Bacillus sp. Xin1

Toyoncin, a Novel Leaderless Bacteriocin That Is Produced by Bacillus toyonensis XIN-YC13 and Specifically Targets B. cereus and Listeria monocytogenes

“…1). The production of many bacteriocins in the B. cereus group was similar to that of toyoncin, such as thuricin 4A-4, ticin, thusin, cerecyclin, and bacicyclicin XIN-1, and their antimicrobial activities were detected only in the exponential growth phase but not after this phase (15,17,18,24,25). This may be attributed to two factors: first, these bacteriocins' gene clusters were only transcribed during the exponential growth phase, which was confirmed in a previous study of thuricin 4A-4 (18), and second, bacteriocin-producing strains secreted some proteases during their growth, which could degrade the synthesized bacteriocins.…”

“…To determine whether toyoncin can inhibit B. cereus spore germination, an assay was performed as described previously ( 15 ). Briefly, 100 μl of 1.0 × 10 7 spores/ml of B. cereus , 800 μl of LB medium, and 100 μl of toyoncin solutions at different final concentrations (0.1, 1, 5, and 10 μM) were mixed and incubated at 30°C for 3 h. Differential interference contrast microscopy images of vegetative cells or spores in the cultures were obtained with a DeltaVision epifluorescence microscope (Applied Precision, Issaquah, WA, USA), and the images were processed with the SoftWoRX Explorer Suite program (Applied Precision).…”

“…The Bacillus cereus group contains spore-forming, aerobic or facultative anaerobic, rod-shaped bacteria and has multiple genetically related species ( 13 , 14 ). Recent studies showed that the B. cereus group is a prominent producer of bacteriocins, and dozens of different bacteriocins, including lantibiotics, unmodified bacteriocins, sactibiotics, and circular bacteriocins, have been biochemically and genetically characterized in this group ( 15 ). Some of these show potent antimicrobial effects on a series of foodborne pathogens and food spoilage bacteria.…”

Three novel leaderless bacteriocins have antimicrobial activity against gram-positive bacteria to serve as promising food biopreservative

“…Chemical preservatives generally have certain detrimental effects, and therefore consumers show increasing demand for safer, healthier and natural biopreservatives [ 4 ]. Bacteriocins are a diverse group of peptides or proteins ribosomally synthesized by bacteria, which can inhibit or kill other bacteria and have a great potential to be used as biopreservatives [ 5 , 6 ]. Generally, bacteriocins produced by gram-positive bacteria can be divided into three major classes: class I that consists of ribosomally synthesized and post-translationally modified peptides (RiPPs) that function as bacteriocins, such as lantibiotics, lipolanthines, linear azol(in)e-containing bacteriocins, thiopeptides, bottromycins, sactibiotics, lasso peptides, glycocins, head-to-tail cyclized bacteriocins; class II that consists of small unmodified peptides including YGNG-motif containing bacteriocins, two-peptide bacteriocins, leaderless bacteriocins and other linear bacteriocins; and class III that consists of large heat-labile bacteriocins, such as tailocins [ 7 ].…”

“…Bacillus thuringiensis is a ubiquitous gram-positive, spore-forming bacterium that produces parasporal crystals during the stationary phase of its growth cycle [ 12 ]. Recent studies have demonstrated that B. thuringiensis is a prominent producer of bacteriocins and contains various types of novel bacteriocins that have not been functionally characterized [ 5 , 13 ]. So far, many bacteriocins have been identified in B. thuringiensis , such as thuricin 4AJ1 (not fully characterized), thuricin 7 (not fully characterized), thuricin Bn1 (sactibiotic), BtCspB (not fully characterized), thurincin H (sactibiotic), thuricin CD (two-peptide sactibiotic) and thuricin Z (sactibiotic) [ 14 – 19 ].…”