Three mutants of the antibiotic nisin Z, in which the Val32 residue was replaced by a Glu, Lys or Trp residue, were produced and characterized for the purpose of establishing the role of charge differences in the C-terminal part of nisin on antimicrobial activity and signaling properties. 1H-NMR analyses showed that all three mutants harbor an unmodified serine residue at position 33, instead o...

Two natural variants of the lantibiotic nisin that are produced by Lactococcus lactis are known. They have a similar structure but differ in a single amino acid residue at position 27; histidine in nisin A and asparagine in nisin Z (J.W.M. Mulders, I.J. Boerrigter, H.S. Rollema, R.J. Siezen, and W.M. de Vos, Eur. J. Biochem, 201:581-584, 1991). The nisin variants were purified to apparent homog...

Nisin is the prototypical example of the lantibiotic family of antimicrobial peptides and has been employed as a food preservative for over half a century. It has also attracted attention due to its potency against a number of multidrug-resistant clinical pathogens. Nisin A is the originally isolated form of Nisin and a further five natural variants have been described which differ by up to 10 ...

Nisin is a 3.4-kDa antimicrobial peptide that, as a result of posttranslational modifications, contains unsaturated amino acids and lanthionine residues. It is applied as a preservative in various food products. The solubility and stability of nisin and nisin mutants have been studied. It is demonstrated that nisin mutants can be produced with improved functional properties. The solubility of n...

Nisin Z and thymol were tested, alone and in combination, for antibacterial activity against Listeria monocytogenes ATCC 7644 and Bacillus subtilis ATCC 33712. The antibacterial effect of nisin Z, produced by Lactococcus lactis KE3 isolated from the traditional Moroccan fermented milk, was greatly potentiated by sub-inhibitory concentrations of thymol in both bacterial strains. Our data showed ...

Innate immunity is triggered by a variety of bacterial molecules, resulting in both protective and potentially harmful pro-inflammatory responses. Further, innate immunity also provides a mechanism for the maintenance of homeostasis between the host immune system and symbiotic or non-pathogenic microorganisms. However, the bacterial factors that mediate these protective effects have been incomp...

The aim of the present study was to evaluate the effects of Ziziphora clinopodioides essential oil (0.1 and 0.2%) and nisin (250 and 500 IU/mL) separately and in combination on survival of Escherichia coli O157:H7 inoculated in Doogh (Iranian yoghurt drink) during storage under refrigerated temperature (4 ± 1°C) for 9 days. Viability of Lactobacillus casei at different concentrations of Z. clin...

The effects of Z. multiflora essential oil (EO) and nisin (N) on fresh rainbow trout (Onchorynchus mykiss) fillets were studied during 18 days storage at 4 ºC. Bacteriological and organoleptical evaluation were performed on fresh rainbow trout as the functions of treatment and storage time. Treatments included the following: A (control), E1 (treated samples with 0.2 % EO), E2 (treated samples w...

The effects of Z. multiflora essential oil (EO) and nisin (N) on fresh rainbow trout (Onchorynchus mykiss) fillets were studied during 18 days storage at 4 ºC. Bacteriological and organoleptical evaluation were performed on fresh rainbow trout as the functions of treatment and storage time. Treatments included the following: A (control), E1 (treated samples with 0.2 % EO), E2 (treated samples w...

The small antimicrobial peptide nisin, produced by Lactococcus lactis, contains the uncommon amino acid residues dehydroalanine and dehydrobutyrine and five thio ether bridges. Since these structures are posttranslationally formed from Ser, Thr, and Cys residues, it is feasible to study their role in nisin function and biosynthesis by protein engineering. Here we report the development of an ex...