title: Loss of IrpT function in Lactococcus lactis subsp. lactis N8 results in increased nisin resistance.
abstract: The antibiotic nisin, produced by Lactococcus lactis subsp. lactis N8, offers an extensive commercial prospect as natural food preservatives. The nisin immunity of the L. lactis strains is regulated by a variety of mechanisms. In this study, we isolated a L. lactis L31 strain with increased nisin resistance from a mini-Mu transposon mutant pool of strain N8. The single Mu insertion in strain L31 was in the irpT gene with unknown function. By comparing the proteomic profiles of L. lactis L31 and its parental strain, we found that changes occurred in the synthesis of a protein involved in cell wall biosynthesis (RmlD). Strain L31 had 13.7% higher content of rhamnose in the cell wall than the N8 strain. Overexpression of RmlD involved in the synthesis of dTDP-L: -rhamnose in the nisin-sensitive MG1363 strain increased nisin resistance of the strain. The results indicate that these cellular proteins effected nisin resistance in L. lactis N8.
authors.affiliation: College of Life Sciences, Nankai University, Tianjin, China. xuanyuanzheng@yahoo.com.cn
authors.forename: Zhengzheng
authors.initials: Z
authors.lastname: Xuanyuan
authors.forename: Zhenzhou
authors.initials: Z
authors.lastname: Wu
authors.forename: Ruiqing
authors.initials: R
authors.lastname: Li
authors.forename: Dezhou
authors.initials: D
authors.lastname: Jiang
authors.forename: Junjie
authors.initials: J
authors.lastname: Su
authors.forename: Haijin
authors.initials: H
authors.lastname: Xu
authors.forename: Yanling
authors.initials: Y
authors.lastname: Bai
authors.forename: Xiuming
authors.initials: X
authors.lastname: Zhang
authors.forename: Per Erik Joakim
authors.initials: PE
authors.lastname: Saris
authors.forename: Mingqiang
authors.initials: M
authors.lastname: Qiao
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015139:Blotting, Southern; D002473:Cell Wall / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D024881:Drug Resistance, Bacterial / Q000235:genetics; D015180:Electrophoresis, Gel, Two-Dimensional; D015870:Gene Expression; D005798:Genes, Bacterial; D013294:Lactococcus lactis / Q000187:drug effects* / Q000235:genetics*; D008074:Lipoproteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D009561:Nisin / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology*; D010957:Plasmids; D016133:Polymerase Chain Reaction; D011499:Protein Processing, Post-Translational
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D008074:Lipoproteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; C094909:NisI protein, Lactococcus lactis; C094910:NisT protein, Lactococcus lactis; D009561:Nisin