Biocompatible organic acids and citrate-stabilized gold nanoparticles were interacted with nisin to generate robust antimicrobial agents, which display archetypical nisin activity even at elevated pH.

Nisin is a membrane active antimicrobial peptide containing unusual dehydrated amino acid residues. The secondary structure of nisin in aqueous solution, membrane mimicking solvents and at various pH values was investigated using circular dichroism. In aqueous solution nisin is largely randomly coiled. In liposomes and at pH 6 and above, however, the presence of a maximum at 195 nm and a minimu...

Background & Aims of the Study: Foodborne illnesses, resulting from consumption of contaminated foods, represent a substantial public health threat. Listeria monocytogenes is a foodborne pathogen bacteria and can cause serious problems in human. Because of this reason, Nowadays various compounds are being used to control these bacteria in foods. The aim of this study was to evaluate antilistari...

Objective(s): The objective of this study was to investigate the antibacterial activities of magnesium oxide nanoparticles (MgO NP) alone or in combination with other antimicrobials (nisin and heat) against Escherichia coli and Staphylococcus aureus in milk.Materials and Methods: First, the combined effect of nisin and MgO nanoparticles was investigated in milk. Then the combined effect of nisi...

Frequent and indiscriminate use of existing battery of antibiotics has led to the development of multi drug resistant (MDR) strains of pathogens. As decreasing the concentration of the antibiotic required to treat Salmonellosis might help in combating the development of resistant strains, the present study was designed to assess the synergistic effects, if any, of nisin, in combination with con...

In Listeria monocytogenes, nisin induced ATP efflux, reduced the intracellular ATP concentration within 1 min, and dissipated the proton motive force within 2 min. Efflux accounted for only 20% of the ATP depletion, suggesting that ATP hydrolysis also occurred. ATP efflux depended on nisin concentration and followed saturation kinetics. These results suggest that nisin breaches the membrane per...

The peptide antibiotic nisin was shown to cause a rapid efflux of amino acids and Rb+ from the cytoplasm of gram-positive bacteria (Staphylococcus cohnii 22, Bacillus subtilis W 23, Micrococcus luteus ATCC 4698, and Streptococcus zymogenes 24). It strongly decreased the membrane potential of cells as judged by the distribution of the lipophilic tetraphenylphosphonium cation. Ascorbate-phenazine...

Derivatives of a cryptic plasmid from Lactobacillus curvatus showed temperature-sensitive replication in thermophilic lactobacilli. The thermosensitive replicon was used to construct the new delivery vector pTN1, which allows site-specific replacement of chromosomal DNA sequences. pTN1 carries an erythromycin resistance marker suitable for selection of single-copy integrants and replicates read...

A transferable dual-plasmid inducible gene expression system for use in lactic acid bacteria that is based on the autoregulatory properties of the antimicrobial peptide nisin produced by Lactococcus lactis was developed. Introduction of the two plasmids allowed nisin-inducible gene expression in Lactococcus lactis MG1363, Leuconostoc lactis NZ6091, and Lactobacillus helveticus CNRZ32. Typically...

the presence of antibacterial activity in bovine β-lactoglobulin and in α-lactalbumin hydrolysates was investigated. the plasmin-digest of β-lactoglobulin (pdβ) and of α-lactalbumin (pdα) were fractionated, using reversed phase high performance liquid chromatography. the antibacterial activity of β-lactoglobulin, α-lactalbumin, nisin, plasmin, pdβ and pdα were in vitro tested against pathogenic...