نوع مقاله: مقاله پژوهشی
نویسندگان
1 دانشجوی دکتری بیوشیمی، دانشکده دامپزشکی، دانشگاه شیراز، شیراز، ایران
2 دانشیار بخش علوم پایه دانشکده دامپزشکی، دانشگاه شیراز، شیراز، ایران
3 استاد بخش بهداشت مواد غذایی، دانشکده دامپزشکی، دانشگاه شیراز، شیراز، ایران
4 دانشیار بخش علوم و صنایع غذایی، دانشکده کشاورزی، دانشگاه شیراز، شیراز، ایران
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Nisin is an antimicrobial peptide used in the food industry as a preservative. However, this peptide has no considerable effect on gram-negative bacteria. In this study, the effect of glycation on the antimicrobial activity of nisin was elucidated against Escherichia coli and Salmonella Typhimurium. A solution of nisin and fivefold concentration of glucose, lactose and dextran and solution of nisin without any sugar were prepared in phosphate buffer and were lyophilized. The lyophilized powder was exposed to 60°C temperature and 70% humidity for 7 days. Every 24 hours, one sample was collected and dissolved in distilled. The equal molar concentration of native and conjugated nisin was made. Percentage of glycation was measured by OPA (ortho-phthalaldehyde) method. MIC50 of nisin was assayed by microdilution method against E. coli and S. Ttyphimurium. The result of this study has revealed that the percentage of glycation is conversely related to the size of carbohydrates in which nisin-glucose had the highest and nisin-dextran had the least percentage of glycation. Glycation of nisin increased the MIC50 of nisin against E. coli after seven days. MIC50 of native nisin and glycated nisin had no difference against S. Typhimurium. From this study, it was concluded that conjugation of nisin with carbohydrates is not able to extend the antimicrobial activity of nisin to gram-negative bacteria.
کلیدواژهها [English]