Nisin is a posttranslationally-modified antimicrobial peptide that has the ability to induce its own biosynthesis. Serines and threonines in the modifiable core peptide part of precursor nisin are dehydrated to dehydroalanines and dehydrobutyrines by the dehydratase NisB, and subsequently cysteines are coupled to the dehydroamino acids by the cyclase NisC. In this study, we applied extensive si...

Nisin-producing transconjugants were generated by mating nisin-producing strains of Lactococcus lactis subsp. lactis with derivatives of L. lactis subsp. lactis LM0230. The sucrose-utilizing ability and reduced bacteriophage sensitivity were also transferred with the nisin-producing character. Pulsed-field gel electrophoretic analysis of genomic DNA from donor, recipient, and nisin-producing tr...

Introduction: Nisin is a bacteriocin produced by Streptococcus and Lactococcus species has antimicrobial activity against other bacteria. omits the need to use chemical preservatives in food due its biological preserving properties. Methods: In present vitro study, we investigated nisin interaction with bovine serum albumin (BSA) using fluorescence spectroscopy surface plasmon resonance (SPR) a...

The basal proton motive force (PMF) levels and the influence of the bacteriocin nisin on the PMF were determined in Listeria monocytogenes Scott A. In the absence of nisin, the interconversion of the pH gradient (Z delta pH) and the membrane potential (delta psi) led to the maintenance of a fairly constant PMF at -160 mV over the external pH range 5.5 to 7.0. The addition of nisin at concentrat...

................................................................................................................................ 7 Tiivistelmä (abstract in Finnish) .......................................................................................... 8 Introduction .......................................................................................................................... 9 1...

The objectives of this study were to determine pH, anti-Listeria and general antimicrobial properties of nisin on ready-to-eat vacuum-packaged diced turkey ham inoculated with Listeria monocytogenes, and the usage level that would exert maximum antimicrobial effect during 63 d of storage. Ready-to-eat diced turkey ham was inoculated with a 5-strain L. monocytogenes cocktail; treated with 0.2, 0...

The promoters in the nisin gene cluster nisABTCIPRKFEG of Lactococcus lactis were characterized by primer extension and transcriptional fusions to the Escherichia coli promoterless beta-glucuronidase gene (gusA). Three promoters preceding the nisA, nisR, and nisF genes, which all give rise to gusA expression in the nisin-producing strain L. lactis NZ9700, were identified. The transcriptional au...

The lantibiotic nisin is produced by several strains of Lactococcus lactis subsp. lactis. The chromosomally located gene cluster nisABTCIPRKFEG is required for biosynthesis, development of immunity, and regulation of gene expression. Inframe deletions in the nisB and nisT genes, and disruption of nisC by plasmid integration, eliminated nisin production and resulted in a strongly reduced level o...

Whey protein isolate and glycerol were mixed to form a matrix to incorporate antimicrobial agents and produce edible films with antimicrobial activity against Listeria monocytogenes strains isolated from cheeses. Various organic acids were used to decrease pH down to approximately 3. In a preliminary assay without nisin, the effect of each organic acid was evaluated with respect to the rheologi...

A reaction mixture is described consisting of a buffered solution of amino acids, salts, growth factors and glucose in which freshly harvested washed Streptococcus Zactis incorporated radioactive tracers and synthesized nisin. Rapid nisin synthesis started after a delay of 30-60 min. but bacteria pre-incubated in the reaction mixture synthesized nisin without delay although the rate of protein ...