Les bactériocines des bactéries lactiques : caractéristiques et intérêts pour la bioconservation des produits alimentaires

Bacteriocins from lactic acid bacteria: interest for food products biopreservation. Bacteriocins from lactic acid bacteria are low molecular weight antimicrobial peptides. They have inhibitory activity against the bacteria that are closed related to the producer strains and a narrow inhibitory spectrum. Nevertheless, most of them have activity against some food-born pathogenic bacteria as Listeria monocytogenes. The application of bacteriocins or bacteriocin producing lactic acid bacteria in food products to inhibit pathogenic or food-spoilage bacteria has then been suggested. This review focuses on the classification, structure, function, mode of action, biosynthesis and current food applications of bacteriocins from lactic acid bacteria

Human papillomavirus oncoproteins induce a reorganization of epithelial-associated γδ T cells promoting tumor formation.

It has been shown that γδ T cells protect against the formation of squamous cell carcinoma (SCC) in several models. However, the role of γδ T cells in human papillomavirus (HPV)-associated uterine cervical SCC, the third-leading cause of death by cancer in women, is unknown. Here, we investigated the impact of γδ T cells in a transgenic mouse model of carcinogenesis induced by HPV16 oncoproteins. Surprisingly, γδ T cells promoted the development of HPV16 oncoprotein-induced lesions. HPV16 oncoproteins induced a decrease in epidermal Skint1 expression and the associated antitumor Vγ5 <sup>+</sup> γδ T cells, which were replaced by γδ T-cell subsets (mainly Vγ6 <sup>+</sup> γδ <sup>low</sup> CCR2 <sup>+</sup> CCR6 <sup>-</sup> ) actively producing IL-17A. Consistent with a proangiogenic role, γδ T cells promoted the formation of blood vessels in the dermis underlying the HPV-induced lesions. In human cervical biopsies, IL-17A <sup>+</sup> γδ T cells could only be observed at the cancer stage (SCC), where HPV oncoproteins are highly expressed, supporting the clinical relevance of our observations in mice. Overall, our results suggest that HPV16 oncoproteins induce a reorganization of the local epithelial-associated γδ T-cell subpopulations, thereby promoting angiogenesis and cancer development

In Vitro Detection And Characterization Of Bacteriocin-Like Inhibitory Activity Of Lactic Acid Bacteria (Lab) Isolated From Senegalese Local Food Products

The prevalence of lactic acid bacteria (LAB) in Senegalese local food products was determined to be 109 CFU/g in millet flour and milk products, and 103 CFU/g in seafood products. These food products are generally preserved by spontaneous fermentation (without addition of starters). Of 220 lactic acid bacteria strains randomly selected from such products, 12 isolates capable of producing bacteriocin-like substances (bac+) were detected. Based on the use of API 50 CH test kits and 16S rDNA sequencing, 11 isolates were characterized as Lactococcus lactis subsp. lactis strains and one as an Enterococcus faecium strain. Nisin- and enterocin B-encoding genes were respectively identified in the bac+ lactococcal strains and the E. faecium strain. Since the bac+ Lc. lactis strains were isolated from different products, it suggests a high potential of growth by these strains in variable ecological environments. Expression of the nisin gene was indicated for one of the lactococcal strains, designated Lc. lactis subsp. lactis CWBI-B1410, which showed the highest in vitro antibacterial activity. An antibacterial preparation prepared from the CWBI-B1410 strain showed many similarities with nisin with regards to its inhibitory effects, heat resistance, protease sensitivity profile, as well as retention time of the antibacterial substances on a C18 column. These results suggest that a nisin-like substance is produced by the CWBI-B1410 strain. This strain has been selected for application as an additional barrier to supplementation with sodium chloride as a means to improve the bacterial quality of fish commodities in Senegal

Antilisterial Activity on Poultry Meat of Amylolysin, a Bacteriocin from Bacillus amyloliquefaciens GA1

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Plasmid-associated bacteriocin production by Lactobacillus LMG21688 Listeria monocytogenes growth rebound in a food system.

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