An antimicrobial peptide [Bacillus antimicrobial peptide (BAMP)] produced by Bacillus paralicheniformis was isolated from the Indian traditional fermented food and characterized. The antimicrobial peptide BAMP showed many unique features such as thermostability (4.0–125°C), pH tolerance (pH 2.0–9.0), and resistance to physiological enzymes (trypsin, chymotrypsin, pepsin, proteinase K, protease, and catalase), and food-grade metal salts do not inhibit the activity. The broad spectrum of BAMP (antimicrobial activity) makes it a suitable candidate for food preservation as well as antimicrobial therapy. BAMP was found to exhibit a bacteriostatic effect on Salmonella typhi and controls the viability of Listeria monocytogenes in chicken meat efficiently. BAMP was found to establish eubiosis, as it is not antagonistic to Lactobacillus. Its non-hemolytic nature makes it suitable for therapy. Various genome prediction tools were adopted and applied to understand their localization, gene arrangement, and type of antimicrobials. Founded on its superior functional attributes, BAMP is a potent new-generation antimicrobial peptide.

Multiple mutations in the β subunit of the RNA polymerase (rpoβ) of Mycobacterium tuberculosis (Mtb) are the primary cause of resistance to rifamycin (RIF). In the present study, bifidobacterial rpoβ sequences were analyzed to characterize the mutations that contribute to the development of intrinsic resistance to RIF, isoniazid, streptomycin and pyrazinamide. Sequence variations, which mapped to cassettes 1 and 2 of the rpoβ pocket, are also found in multidrug-resistant Mtb (MDR Mtb). Growth curves in the presence of osmolytes and different concentrations of RIF showed that the bacteria adapted rapidly by shortening the growth curve lag time. Insight into the adapted rpoβ DNA sequences revealed that B. adolescentis harbored mutations both in the RIF pocket and in regions outside the pocket. The minimum inhibitory concentrations (MICs) and mutant prevention concentrations (MPCs) indicated that B. longum, B. adolescentis and B. animalis are resistant to antitubercular drugs. 3D-homology modeling and binding interaction studies using computational docking suggested that mutants had reduced binding affinity towards RIF. RIF-exposed/resistant bacteria exhibited variant protein profiles along with morphological differences, such as elongated and branched cells, surface conversion from rough to smooth, and formation of a concentrating ring.

The food industry produces highly perishable products. Food spoilage represents a severe problem for food manufacturers. Therefore, it is important to identify effective preservation solutions to prevent food spoilage. Ocins (e.g., bacteriocins, lactocins, and enterocins) are antibacterial proteins synthesized by bacteria that destroy or suppress the growth of related or unrelated bacterial strains. Ocins represent a promising strategy for food preservation, because of their antagonist effects toward food spoilage microorganisms, high potency, and low toxicity. Additionally, they can be bioengineered. The most common and commercially available ocins are nisin, plantaracin, sakacin P, and pediocin. Several ocins have been characterized and studied biochemically and genetically; however, their structure-function relationship, biosynthesis, and mechanism of action are not understood. This narrative review focuses primarily on ocins and their relevance to the food industry to help prevent food spoilage. In particular, the applications and limitations of ocins in the food industry are highlighted.

The generation of a zone of inhibition on a solid substrate indicates the bioactivity of antimicrobial peptides such as bacteriocin and enterocin. The indicator strain plays a significant role in bacteriocin assays. Other characteristics of bacteriocins, such as their dispersal ability and the different zymogram components, also affect bacteriocin assays. However, universal well diffusion assays for antimicrobials, irrespective of their ability to diffuse (bacteriocin, enterocin), do not exist. The ability of different zymography components to generate non-specific activities have rarely been explored in the literature. The purpose of the present work was to evaluate the impact of two major factors (diffusion and no diffusion) in a solid substrate bioassay, and to document the adverse effects of sodium dodecyl sulfate in zymograms used to estimate the approximate molecular weight of bacteriocins.