摘要
目的:幽门螺杆菌(H pylori)可产生H pylori源杀菌肽样抗菌肽,这种多肽与昆虫杀菌肽cecropins的结构和功能类似.我们研究H pylori源杀菌肽样抗菌肽Hp(2-20)对消化道常见致病菌的杀伤作用,探讨H pylori感染者的生存竞争优势. 方法:采用琼脂扩散法检测Hp(2-20)对消化道常见致病菌的抗菌活性及致死浓度,平板菌落计数法检测Hp(2-20)的抑菌率.采用染料排斥试验测定Hp(2-20)对胃黏膜上皮细胞生长的影响. 结果:Hp(2-20)对消化道常见致病菌福氏志贺菌、伤寒、副伤寒沙门菌和致病性大肠杆菌具有杀伤作用,致死浓度为65-197μmoL/L,并可在12 min内完全抑制细菌生长. 但小肠结肠炎耶氏杆菌及金黄色葡萄球菌对Hp(2—-0)不敏感,致死浓度>1 014 μmoL/L.Hp(2-20)的杀菌作用明显低于Cecropin B,对胃黏膜上皮细胞无裂解. 结论:H pylori源杀菌肽样抗菌肽Hp(2-20)可抑制胃肠道内快速繁殖的致病菌的生长,对胃黏膜上皮细胞无影响. 感染Hp的宿主可能拥有生存竞争优势.
AIM: To study the in vitro killing effects of cecropin-like antibacterial peptide from H pylori Hp (2-20) on the gastrointestinal bacterial pathogens and to explore the survival advantage to the host of infection with H pylori. METHODS: The inhibition zone assay was used to determine anti-bacterial activity and lethal concentrations of H pylori antibacterial peptide Hp (2-20) on the gastrointestinal bacterial pathogens. The rate of killing of E.coliK12 D31 (standard strain) by Hp(2-20) was estimated by counting viable bacteria based on counting of colonies grown in Luria-Bertani plate. The cytotoxicity of the Hp (2-20) peptides on human gastric epithelial cell line was measured by trypan blue exclusion test. RESULTS: In vitro studies, the Hp (2-20) destroyed the gastrointestinal bacterial pathogens such as Shigella flexneri, Salmonella typhi, Salmonella paratyphi and en teropathogenic E.coli. The lethal concentrations (LC) were 65-197 μmoL/L. The viable bacterial count dropped to zero after 12 min incubation with Hp (2-20) concentration closed to the LC value. The Hp (2-20) was inactive against the strains of Yersinia enterocolitica and Staphylococcus aureus and had much higher LC (over 1 014 μmol/L). The killing effects of Cecropin B were more pronounced than Helicobacter peptide Hp (2-20). The synthetic peptide Hp(2-20) showed no lytic or toxic activity against the human gastric epithelial cell line GES-1. CONCLUSION: The cecropin-like antibacterial peptide from H pylori Hp (2-20) is active against faster-growing gastrointestinal bacterial pathogens. There is no effect on the human gastric epithelial cells. H pylori may actually have beneficial effects on infected carriers who are heavily ex- posed to other gastrointestinal pathogens.
出处
《世界华人消化杂志》
CAS
2004年第6期1321-1324,共4页
World Chinese Journal of Digestology
