Synergistic antibacterial mechanism of the Lactobacillus crispatus surface layer protein and nisin on Staphylococcus saprophyticus.
SlpB, a surface layer protein isolated from Lactobacillus crispatus, has the potential to enhance the antimicrobial activity of nisin. Previous research indicated that, when combined with nisin, SlpB acted synergistically to inhibit Staphylococcus saprophyticus growth, thus extending the shelf life of chicken meat. In order to understand how SlpB enhances the antibacterial activity of nisin, electron microscopy, confocal laser scanning microscopy, flow cytometry and transmembrane electrical potential analysis were used to study cell wall organization and cell membrane integrity. No remarkable bacteriolytic effects were observed, indicating that cell death could not be attributed to cell lysis, although SlpB caused dramatic modifications of cell wall, thereby altering cell shape. The combination of SlpB and nisin also induced the release of ATP or UV-absorbing materials, as well as sudden dissipation of the transmembrane electrical potential by compromising membrane integrity. Considering that SlpB led to structural disorganization of the cell wall, and nisin access is enhanced to form a stable pore, cell death is a predictable outcome. SlpB significantly enhanced the effect of nisin at half of the minimum inhibitory concentration, which resulted in cell death by destroying the cell wall and cell membrane, therefore providing a new, feasible approach in food preservation.
Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, PR China.
Zhilan
Z
Sun
Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, PR China.
Pengpeng
P
Li
Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, PR China. fangliu82@163.com.
Fang
F
Liu
Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, PR China.
Huan
H
Bian
Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, PR China. daoyingwang@yahoo.com.|Key Laboratory of Meat Processing and Quality Control, Ministry of Education, Nanjing Agricultural University, Nanjing, 210095, PR China. daoyingwang@yahoo.com.
Daoying
D
Wang
Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, PR China.
Xiaomeng
X
Wang
Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, PR China.
Ye
Y
Zou
Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, PR China.
Chong
C
Sun
Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, PR China.|Key Laboratory of Meat Processing and Quality Control, Ministry of Education, Nanjing Agricultural University, Nanjing, 210095, PR China.
Weimin
W
Xu
D000818:Animals; D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000378:metabolism*; D001426:Bacterial Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002462:Cell Membrane / Q000187:drug effects; D002645:Chickens; D004357:Drug Synergism; D005434:Flow Cytometry; D000070003:Lactobacillus crispatus / Q000737:chemistry*; D008460:Meat / Q000382:microbiology; D008562:Membrane Glycoproteins / Q000302:isolation & purification / Q000378:metabolism*; D008564:Membrane Potentials / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D009561:Nisin / Q000302:isolation & purification / Q000378:metabolism*; D057790:Staphylococcus saprophyticus / Q000187:drug effects* / Q000254:growth & development
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D008562:Membrane Glycoproteins; C055764:S-layer proteins; D009561:Nisin