Sugiyama T, Kido N, Komatsu T, Ohta M, Kato N
Department of Bacteriology, Nagoya University School of Medicine, Aichi, Japan.
J Bacteriol. 1991 Jan;173(1):55-8. doi: 10.1128/jb.173.1.55-58.1991.
To investigate the effect of chromosomal mutation on the synthesis of rfe-dependent Escherichia coli O9 lipopolysaccharide (LPS), the cloned E. coli O9 rfb gene was introduced into Salmonella typhimurium strains defective in various genes involved in the synthesis of LPS. When E. coli O9 rfb was introduced into S. typhimurium strains possessing defects in rfb or rfc, they synthesized E. coli O9 LPS on their cell surfaces. The rfe-defective mutant of S. typhimurium synthesized only very small amounts of E. coli O9 LPS after the introduction of E. coli O9 rfb. These results confirmed the widely accepted idea that the biosynthesis of E. coli O9-specific polysaccharide does not require rfc but requires rfe. By using an rfbT mutant of the E. coli O9 rfb gene, the mechanism of transfer of the synthesized E. coli O9-specific polysaccharide from antigen carrier lipid to the R-core of S. typhimurium was investigated. The rfbT mutant of the E. coli O9 rfb gene failed to direct the synthesis of E. coli O9 LPS in the rfc mutant strain of S. typhimurium, in which rfaL and rfbT functions are intact, but directed the synthesis of the precursor. Because the intact E. coli O9 rfb gene directed the synthesis of E. coli O9 LPS in the same strain, it was suggested that the rfaL product of S. typhimurium and rfbT product of E. coli O9 cooperate to synthesize E. coli O9 LPS in S. typhimurium.
为了研究染色体突变对rfe依赖型大肠杆菌O9脂多糖（LPS）合成的影响，将克隆的大肠杆菌O9 rfb基因导入在LPS合成中涉及的各种基因有缺陷的鼠伤寒沙门氏菌菌株中。当将大肠杆菌O9 rfb导入在rfb或rfc中有缺陷的鼠伤寒沙门氏菌菌株时，它们在其细胞表面合成了大肠杆菌O9 LPS。在导入大肠杆菌O9 rfb后，鼠伤寒沙门氏菌的rfe缺陷型突变体仅合成了极少量的大肠杆菌O9 LPS。这些结果证实了被广泛接受的观点，即大肠杆菌O9特异性多糖的生物合成不需要rfc，但需要rfe。通过使用大肠杆菌O9 rfb基因的rfbT突变体，研究了合成的大肠杆菌O9特异性多糖从抗原载体脂质转移到鼠伤寒沙门氏菌R核心的机制。大肠杆菌O9 rfb基因的rfbT突变体未能在鼠伤寒沙门氏菌的rfc突变体菌株中指导大肠杆菌O9 LPS的合成，在该菌株中rfaL和rfbT功能是完整的，但指导了前体的合成。因为完整的大肠杆菌O9 rfb基因在同一菌株中指导了大肠杆菌O9 LPS的合成，所以表明鼠伤寒沙门氏菌的rfaL产物和大肠杆菌O9的rfbT产物协同作用在鼠伤寒沙门氏菌中合成大肠杆菌O9 LPS。
