鸭源鸡杆菌tolC无痕敲除株的构建及生物学特性分析OA北大核心CSTPCD

TolC family protein(TolC),an outer membrane channel protein,is widespread in Gram-negative bacteria,which mediates extracellular transport of various substances and plays important roles in the bacterial biological functions.The identification of the functions of TolC in the virulence of Gallibacterium anatis would play crucial roles for prevention and control of this disease.In this study,traceless deletion mutant of tolC(ΔtolC)was constructed by natural transformation using a clinical isolate Yu-PDS-RZ-1-SLG(WT)and the biological characteristics of the mutant strain was investigated.Compared with WT strain,the results of ΔtolC showed that bacteria colonies and zone of hemolysis were smaller,the logarithmic growth phase was delayed 2 h with slower growth rate and weakened biofilm formation ability(P＜0.001).In addition,the survival rates under high temperature,oxidative stress and osmotic pressure circumstance were significantly reduced(P＜0.01).The sensitivity to some antibiotics in the planktonic and membrane states increased:in the planktonic state,the sensitivity of ΔtolC to SDS,fosfomycin,and doxycycline increased by 32,8,and 4 times,respectively;in the membrane state,the sensitivity of ΔtolC to SDS,fosfomycin,and doxycycline increased by 16,8,and 8 times,respectively;while the sensitivity to neomycin sulfate and kanamycin remained unchanged.The adhesion ability of ΔtolC to human(Homo sapiens)cervical cancer cell line(Hela)reduced.The construction and analysis of biological characteristics of tolC traceless knockout strain ΔtolC provides basic data for the study of the biological function,pathogenic mechanism,and drug resistance mechanism of TolC protein in G.anatis.