Effect of core oligosaccharide structural transformation on autoaggregation in Escherichia coli

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 W3110 in 12 hours of standing at 4 °C. The mutants of core OS deficiency (ΔwaaC) and outer core OS deficiency (ΔwaaG) were used to investigate the properties of autoaggregation. In this study,the autoaggregation ratios of ΔwaaC and ΔwaaG 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 offlu 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.