摘要
目的探讨金黄色葡萄球菌SaeRS二元调控系统在人血浆蛋白调控细菌凝集和生物被膜形成中的作用机制。方法收集金黄色葡萄球菌感染常见的临床克隆菌株,Newman(NM)菌株中由于SaeS第一个跨膜区点突变(L18P)导致SaeRS二元调控系统处于持续活化状态,为了探索不同菌株中SaeRS系统的调控功能,本研究分别以USA300和NM菌株为背景,构建SaeRS二元调控系统敲除菌株USA300Δsae和NMΔsae,在含有乏血小板血浆(PPP)和富血小板血浆(PRP)条件下分别检测不同菌株凝集和生物被膜形成的能力。采用反转录-聚合酶链反应检测不同菌株在PPP作用后其SaeRS二元调控系统调控的靶基因表达水平。结果人血浆PPP可促进金黄色葡萄球菌不同临床分离菌株凝集,人血浆PPP和PRP均可促进金黄色葡萄球菌不同临床分离菌株生物被膜形成,但不同菌株之间存在差异,如人血浆蛋白促进NM菌株凝集能力明显强于USA300菌株,提示NM菌株中SaeRS系统的高度活化状态可能参与血浆蛋白促进细菌的凝集过程。进一步研究发现,人血浆蛋白不能促进sae敲除菌株的凝集和生物被膜形成能力;sae敲除菌株中互补表达SaeRS和高度活化状态的SaeRS L18P均可回复人血浆蛋白促进细菌凝集活性;USA300菌株中SaeRS通过调控凝固酶coa表达促进金黄色葡萄球菌凝集和生物被膜形成,而在NM菌株中,高度活化的SaeRS二元调控系统通过调节多个基因(coa、eap、clfb、emp)的表达发挥功能。结论人血浆蛋白可促进金黄色葡萄球菌凝集和生物被膜形成,SaeRS二元调控系统单个氨基酸位点突变改变该系统的调控网络。
Objective To explore the mechanism of the Staphylococcus aureus SaeRS binary regulation system in the regulation of bacterial aggregation and biofilm formation of human plasma proteins.Methods Collected common clinical cloned strains of Staphylococcus aureus infection,in the Newman(NM)strain,the SaeRS binary regulation system was continuously activated due to a point mutation in the first transmembrane region of SaeS(L18P).In order to explore the regulatory functions of the SaeRS system in different strains,this study used the USA300 and NM strains as the background to construct the SaeRS binary regulatory system knockout strains USA300Δsae and NMΔsae.Under the conditions of platelet-poor plasma(PPP)and platelet-rich plasma(PRP),the ability of different strains to aggregate and form biofilm was detected respectively.Reverse transcription-polymerase chain reaction was used to detect the expression levels of target genes regulated by the SaeRS binary regulatory system of different strains after PPP action.Results Human plasma PPP could promote the agglutination of different clinical isolated strains of Staphylococcus aureus,and both human plasma PPP and PRP could promote the biofilm formation of different clinical isolated strains of Staphylococcus aureus,but there were differences between different strains.For example,the ability of human plasma protein to promote the agglutination of the NM strain was significantly stronger than that of the USA300 strain,suggested that the highly activated state of the SaeRS system in the NM strain might be involved in the process of plasma protein promoting the agglutination of bacteria.Further research found that human plasma protein could not promote the agglutination and biofilm formation ability of sae knockout strains.The complementary expression of SaeRS and the highly activated SaeRS L18P in the sae knockout strain could restore the pro-bacterial agglutination activity of human plasma proteins.In the USA300 strain,SaeRS promoted Staphylococcus aureus agglutination and b
作者
胡刘平
刘倩
HU Liuping;LIU Qian(Department of Clinical Laboratory,Renji Hospital,Shanghai JiaoTong University School of Medicine,Shanghai 310115,China;Department of Clinical Laboratory,Sixth People′s Hospital,Shanghai JiaoTong University,Shanghai 201306,China)
出处
《国际检验医学杂志》
CAS
2021年第23期2817-2821,2829,共6页
International Journal of Laboratory Medicine
基金
国家自然科学基金资助项目(81772139、82072235)。
