Project description:Owing to their ability to secrete antimicrobials and benefit human health, lactic acid bacteria (LAB) cultures are an attractive nontoxic alternative to antibiotics for preserving food and combating pathogenic infections. Given that this strategy has several limitations, including strain-dependent antimicrobial effectiveness, reduced efficacy against multidrug-resistant strains, and difficulties in large-scale production without bacterial contamination, current research focuses on identifying and utilizing endolysins (enzymes that degrade bacterial cell walls) produced by novel or engineered LAB cultures to inhibit pathogen growth. The challenges faced by this approach (e.g., bactericidal activity lower than that of antibiotics, susceptibility to degradation by proteases, and high purification and quality control costs) can be overcome using engineered LAB-derived extracellular vesicles (LEVs) displaying pathogen-specific endolysins on their surface to directly recognize and eliminate target pathogens. Given that no LEV surface-displayed proteins (SDPs) have been characterized to date, this study identifies and characterizes a LEV SDP (LP-SDP3) from Lacticaseibacillus paracasei using proteomic analysis, heterologous expression of candidate SDPs, biochemical analysis, and SpyTag–SpyCatcher reactions. LP-SDP3 homologs are found in Escherichia coli and other LAB strains, exhibiting the same function in E. coli and Lactococcus lactis. Endolysin (PlyF307SQ-8C)-displaying LEVs derived from L. paracasei selectively kill Staphylococcus aureus, exhibiting an activity comparable with that of purified PlyF307SQ-8C. This study is the first to identify a universal extracellular vesicle SDP for E. coli and LAB strains, demonstrating its potential as a platform for developing endolysin–extracellular vesicle antibacterials without the need for labor-intensive and costly endolysin preparation.
Project description:We report here the complete genome sequence of Lacticaseibacillus paracasei NSMJ15, isolated from makgeolli (a traditional Korean fermented liquor) and shown to have potentially probiotic characteristics. The genome consisted of a 2.79-Mbp chromosome contig and four plasmids having a total of 2,947 genes, including 2,690 coding sequences.
Project description:This study took the advantage of the availability of a methylated mutant (ΔpglX ) of Lacticaseibacillus (L.) paracasei Zhang to test our hypothesis that DNA methylation could protect lactic acid bacteria from freeze-drying and post-freeze-drying storage stresses. Active cultures of the wild-type and mutant were freeze-dried and stored at 30 ℃ for different duration (30, 60, and 90 days) before reactivation. Proteomic analyses was implemented to identify differentially expressed proteins (DEPs) of the bacteria.
Project description:Bacteria that live in the acidic environment face number of growth-related challenges from the intracellular pH changes. In order to survive under acidic environment, Lactic acid bacteria must employ multiple genes and proteins to regulate the relative pathways.
Project description:Bacteria that live in the acidic environment face number of growth-related challenges from the intracellular pH changes. In order to survive under acidic environment, Lactic acid bacteria must employ multiple genes and proteins to regulate the relative pathways.
Project description:Lacticaseibacillus paracasei strain VHProbi F22 is a proprietary probiotic strain that can be found in the Chinese market. Here, we investigate the whole-genome sequence of this bacterium. The whole genome contains a chromosome and a plasmid.
