核心多糖结构变异对大肠杆菌自凝集特性的影响  

Effect of Core Oligosaccharide Structural Transformation on Autoaggregation in Escherichia coli

作　　者：王洲[1,2] 李烨 任格 王小元[1,2] 

机构地区：[1]食品科学与技术国家重点实验室江南大学,江苏无锡214122 [2]江南大学生物工程学院,江苏无锡214122

出　　处：《食品与生物技术学报》2017年第6期569-575,共7页Journal of Food Science and Biotechnology

基　　金：国家自然科学基金项目(31170069);国家973计划项目(2012CB725202)

摘　　要：以大肠杆菌K-12菌株为研究对象,通过对比分析野生型W3110及脂多糖分子核心多糖结构变异菌株的自凝集特性,对细胞膜上核心多糖结构与细菌自凝集的相关性进行分析。结果表明,核心多糖的结构变异会增加大肠杆菌的自凝集能力,在4℃下静置12 h,突变菌株自凝集率较野生型菌株提高近3倍。以核心多糖缺失突变菌株ΔwaaC和外核心糖缺失突变菌株ΔwaaG为研究对象,进行菌株自凝集动力曲线测定。结果表明,在静置2 h后,菌株自凝集率均可达80%以上。通过对不同温度和不同菌液浓度下菌株自凝集特性的分析,温度与菌株的自凝集特性无明显相关性,而较高的菌液浓度能够提高菌株的自凝集能力。为分析突变菌株自凝集形成机制,以野生型W3110为对照,对突变菌株自转运蛋白编码基因flu进行RT-PCR分析,突变菌株中flu基因的转录水平增加2~4倍。同时,利用表达质粒pWSK29构建自转运蛋白质表达载体,通过诱导表达,确定自转运蛋白质在大肠杆菌W3110自凝集中的作用。Theautoaggregation level of E.coli K-12 W3110 was tested by the comparison with its mutants in core oligosaccharide （core OS）,and the relationship between autoaggragation and the structure of core oligosaccharide was analyzed. The results showed that the mutation of core OS would induced autoaggregation. The autoaggregation ratio of mutants were three times better than wild type W31 10 in 12 hours of standing at 4 ℃. The mutants of core OS deficiency （ΔwaaC） and outer core OS deficiency （ΔwaaG） were used to investigate the properties of autoaggregation. In thisstudy,the autoaggregation ratios of ΔwaaC and AwaaG strains were 80% after 2 hours of static culture. The autoaggregation level with different temperature and cell concentration were also tested, the results indicated that the autoaggregation was not influenced by the temperature, but enhanced by the increase of cell concentration. In order to elucidate the mechanism of autoaggregation,the transcription level of flu （gene of Ag43 ） was analyzed between W3110 and the mutants by RT-PCR, and the results showed that the transcription of flu was raised 2-4 times in the mutants of core OS, and it may be the reason of the increase of autoaggregation ratio in mutants. Finally, the preliminary results of gene expression of flu proved the effect of Ag43 on autoaggregation in W3110.

关 键 词：脂多糖 核心多糖 细胞膜 自凝集 自转运蛋白 

分 类 号：Q93[生物学—微生物学]