In Vitro Insights into Bacteriocin-Mediated Modulation of Chicken Cecal Microbiota.

Reducing the use of antibiotics in animal husbandry is essential to limit the spread of resistance. A promising alternative to antibiotics resides in bacteriocins, which are antimicrobial peptides produced by bacteria showing a great diversity in terms of spectrum of activity, structure, and mechanism of action. In this study, the effects of diverse bacteriocins on the composition and metabolic activity of chicken cecal microbiota were examined in vitro, in comparison with antibiotics.

Synthesis and structure-activity study of the antimicrobial lipopeptide brevibacillin.

The antimicrobial lipopeptide brevibacillin is a non-ribosomally synthesized peptide produced by with inhibitory activity against several clinically relevant Gram-positive pathogenic bacteria such as , , and . In this study, we report the total synthesis of brevibacillin and analogues thereof as well as structure-activity relationship and cytotoxicity studies. Several novel synthetic analogues exhibited high inhibitory activities with minimal inhibitory concentration values in the low micromolar range against several bacteria including Gram-positive , , , and as well as Gram-negative and .

Synthesis, antimicrobial activity, and mechanistic studies of enterocin DD14, a leaderless two-peptide bacteriocin.

Bacteriocins are promising alternatives to antibiotics in the food, veterinary and medical sectors, but their study and use is often hampered by the low yields and high costs associated with their purification from naturally occurring bacteria. Chemical synthesis has emerged as a means to overcome this limitation and design more active variants. In this study, microwave-assisted solid-phase peptide synthesis was used to produce the leaderless two-peptide bacteriocin enterocin DD14 (EntDD14), composed of EntDD14A (44 amino acids) and EntDD14B (43 amino acids).

Antimicrobial Activity of Synthetic Enterocins A, B, P, SEK4, and L50, Alone and in Combinations, against .

Multidrug-resistant infections are a major threat to the poultry industry. Effective alternatives to antibiotics are urgently needed to prevent these infections and limit the spread of multidrug-resistant bacteria. The aim of the study was to produce by chemical synthesis a set of enterocins of different subgroups of class II bacteriocins and to compare their spectrum of inhibitory activity, either alone or in combination, against a panel of twenty isolates.

Convenient route to Fmoc-homotyrosine metallaphotoredox catalysis and its use in the total synthesis of anabaenopeptin cyclic peptides.

Herein, we report the first solid-phase total synthesis of the natural cyclic peptide anabaenopeptin F and the use of metallaphotoredox catalysis to overcome the key challenges associated with the preparation of the non-proteinogenic amino acid homotyrosine contained in these peptides. Starting from L-homoserine, enantiopure Fmoc-protected homotyrosine was prepared in a straightforward manner by metallaphotoredox catalysis with -Fmoc-()-2-amino-4-bromobutanoic acid and 4--butoxybromobenzene partners. The prepared protected amino acid was used in solid-phase peptide synthesis to achieve the total synthesis of anabaenopeptin F and establish the stereochemistry of the isoleucine residue.