Expression of 4kD scorpion defensin and its in vitro synergistic activity with conventional antibiotics.
The 4kD scorpion defensin (SD) is a potent disulfide-linked peptide. In this study, we expressed it in methylotrophic yeast Pichia pastoris and purified it using Ni-NTA His Bind Resin. We investigated its in vitro antibacterial activity and effect in combination with several conventional antibiotics. We first examined its antibacterial activity towards several Gram-positive and Gram-negative bacteria. Then we used the broth microdilution method to test drugs alone and in combination and used the fractional inhibitory concentration (FIC index) to classify the drug interactions. Our study showed the expressed SD peptide has antibacterial activity against Salmonella typhimurium, E. coli and S. aureus etc. Synergy or additive interaction was observed between SD and Norfloxacin, Polymyxin B and Ampicillin. Cell growth tests showed that combination of SD and Norfloxacin can improve their activity against bacteria. This result maybe permit lower using of the conventional antibiotic agents more effectively and safely.
Food and Bioengineering College, He'nan University of Science and Technology, Luoyang, 471003 He'nan, People's Republic of China. mingfuniu2004@yahoo.com.cn
Mingfu
M
Niu
Xiang
X
Li
Qiang
Q
Gong
Chen
C
Wang
Cuili
C
Qin
Wenhui
W
Wang
Puyan
P
Chen
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects* / Q000254:growth & development; D023082:Defensins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology*; D004357:Drug Synergism; D015870:Gene Expression; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D008970:Molecular Weight; D010843:Pichia / Q000235:genetics / Q000378:metabolism; D012605:Scorpions / Q000235:genetics / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D023082:Defensins