BPI功能区合成肽体外杀菌能力的研究

Study of the bactericidal capability of BPI functional fragment in vitro

目的：研究 Ｂ Ｐ Ｉ功能区合成肽体外杀菌能力。方法：大肠杆菌 Ｊ５ 、绿脓杆菌 Ｐ Ａ１０３ ，稀释成１×１０５ｃｆｕ／ｍ ｌ，加入不同浓度的 Ｂ Ｐ Ｉ合成肽。比较ｐ Ｈ、菌量、血清蛋白浓度对其杀菌能力的影响，同时观察细菌形态变化。结果： Ｂ Ｐ Ｉ功能区片段与细菌作用０．５～２ ｈ 杀菌力最强。酸性条件下杀菌活性增强，碱性条件下减弱；细菌浓度愈低杀菌力愈强，杀菌活性随血清浓度升高而增强。 Ｂ Ｐ Ｉ功能区片段与细菌作用５ ｍ ｉｎ，外膜出现轮廓模糊，３０ ｍ ｉｎ 见细菌裂解。结论： Ｂ Ｐ Ｉ功能区片段具有杀菌能力，其杀菌活性可能是通过与细菌外膜结合而发挥作用。

Objective: To observe the bactericidal activity of BPI functional fragment in vitro . Methods: E coli J 5 and Pseudomonas aeruginosa PA 103 were diluted to 1×10 5cfu/ml and different concentrations of BPI fragment were added. The effects of pH, number of bacteria and serum concentration of protein on the bactericidal activity of BPI fragment were studied. Meanwhile, the morphological changes of the bacteria were observed. Results: The bactericidal activity was the strongest when BPI fragment was cultured with the bacteria for 0.5 to 2 h and it increased with acidity and decreased with alkalinity. The bactericidal activity increased considerably along with the increase of bacterial number and serum concentration. When BPI fragment was cultured with the bacteria for 5 min, their outer membrane became fuzzy and cracked cells were found under electron microscopy after 30 min of culture. Conclusion: The bactericidal capability of BPI functional fragment is quite similar to that of BPI and it is possible that BPI fragment exercises its killing effect on bacteria through its contact with the bacterial outer membrane.