Nisin, a food preservative produced by Lactococcus lactis, affects the localization pattern of intermediate filament protein in HaCaT cells.

Nisin is a food preservative produced by Lactococcus lactis subsp. lactis. Previous blood biochemical research revealed that nisin has physiological effects in mammals; although the site of action has yet to be identified, keratinocytes have been proposed as a possible target. In this study, we investigated whether nisin affects keratinocytes by examining the effects on eukaryotic intermediate filaments in HaCaT human keratinocytes. Treatment with 93 µg/ml nisin for 24 h decreased the localization of the intermediate filament proteins cytokeratin (CK)5 and CK17 at the cell periphery, which were distributed in a limited area in a ring- or net-like shape. However, this was not observed upon treatment for 6 h. The results of a serial dilution assay revealed that the effect on CK17 localization depends on the nisin concentration and were observed at ≥47 µg/ml. Moreover, this effect was partially blocked by treatment with the calcium channel blocker bepridil. Thus, despite the long history of nisin as being safe for humans, it has measurable effects on the keratinocyte cytoskeleton. Our findings also indicate that CK5 and CK17 can serve as markers for evaluating the effects of nisin on keratinocytes.

[Nisin inactivation in a culture of the producer Streptococcus lactis strain MGU]. / Inaktivatsiia nizina v kul'ture produtsenta Streptococcus lactis shtamm MGU.

The intensive biosynthesis of nizin on the glucose-yeast medium is observed during the logarithmic and early lag phases of the staphylococcal growth. The ratio of nizin in the fermentation broth (free nazin) and that bound with the cells depended on pH of the medium. When pH was maintained at 6.6-6.8, the amount of nazin in the cells during and growth logarithmic phase was equal to its amount in the fermentation broth filtrate. During the lag phase marked inactivation of nizin was noted. periodical feeding of casein prevented the nizin inactivation. The preliminary data are indicative of the enzymatic nature of the antibiotic.