Thuricins: Novel Leaderless Bacteriocins with Potent Antimicrobial Activity Against Gram-Positive Foodborne Pathogens

Abstract

Bacteriocins are bacterial-derived peptides that exhibit antimicrobial activity and can be used as food preservatives. Here, using the indicator strain Bacillus cereus CMCC63301, we screened and identified a Bacillus thuringiensis LX43 strain that exhibits potent antimicrobial activity and harbors a putative leaderless bacteriocin gene cluster (thn gene cluster). Five novel leaderless bacteriocins, thuricin A1, A2, A3, A4, and A5, encoded by the thn gene cluster, were purified and identified. Thuricin A5 was regarded as a representative and showed remarkable antimicrobial activity against foodborne pathogens B. cereus, Clostridium perfringens, Listeria monocytogenes, and Staphylococcus aureus, likely by damaging their cell envelope. Moreover, thuricin A5 displayed good thermal and pH stability, with no hemolytic activity and cytotoxicity, indicating its wide applicability and biosafety. Furthermore, thuricin A5 effectively inhibited or eradicated foodborne pathogens in skim milk at 25 °C in a dose-dependent manner, affirming its potential for use as a novel biopreservative in foods.

Isolation of endophytic strains of Bacillus thuringiensis from wild plant seeds: A potential new biotechnological development

“…Another argument about the idea of some kind of uniqueness among the endophytic B. thuringiensis strains were the 15 isolates whose subspecies were not identi ed by the hag gene sequencing, not only because all they might belong to a new subspecies of B. thuringiensis, as all 15 isolates showed a very similar hag sequence among them, with a percentage of identity higher than 98.4%, but also because of their high relationship with a previously reported strain of B. thuringiensis called LX43, a bacteriocin producing strain (Deng et al 2022). The bacteriocin production ability of the endophytic isolates is under study.…”

In vitro and in silico characterization of N-formylated two-peptide bacteriocin from Enterococcus faecalis CAUM157 with anti-listeria activity

“…These results verify the value of bacteriocins as potential postbiotics derived from E. faecalis M157, circumventing live microorganism disadvantages that risk spreading antimicrobial drug resistance genes and other virulence factors. Furthermore, the puri ed bacteriocins can be applied in the context of the food industry to control various bacterial pathogens and spoilage microorganisms [53,54]. The high stability and strong inhibitory activity of M157 bacteriocins against a broad range of pathogenic microorganisms offer a promising option for food preservation as a substitute for chemical preservatives [55].…”

The Probiotic Bacillus subtilis MB40 Improves Immunity in a Porcine Model of Listeriosis

“…Specific to Listeria , several antimicrobial molecules secreted by Bacillaceae strains have been shown to mitigate LM growth in culture [ 62 , 64 , 69 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 ]. In particular, a subtilin-type bacteriocin peptide from Bacillus subtilis JS-4 was shown by confocal laser-scanning microscopy and electron microscopy to increase LM cell membrane permeability, trigger potassium ion leakage and pore formation, and damage cell membrane integrity [ 89 ].…”