Mouriño M, Madrid C, Balsalobre C, Prenafeta A, Muñoa F, Blanco J, Blanco M, Blanco J E, Juarez A
Departamento de Microbiología, Facultad de Biología, Universidad de Barcelona, Spain.
Infect Immun. 1996 Jul;64(7):2881-4. doi: 10.1128/iai.64.7.2881-2884.1996.
We constructed hha derivatives from both a clinical uropathogenic Escherichia coli isolate (strain FVL4) and a wild E. coli strain causing bovine diarrhea (strain CCB21) and analyzed the effect of the hha allele on the expression of the different virulence factors exhibited by these strains. Expression of hemolysin and of the Vir antigen was altered in hha mutants. Whereas production of hemolysin by strain FVL4 was repressed both at a low temperature and at high osmolarity, the hha allele accounted for a significant increase of hemolysin production under these conditions. Also, the low temperature-sensitive expression of the Vir adhesin was modified in hha mutants, which were able to express this adhesin at a low temperature. Expression of other virulence factors, such as cytotoxic necrotizing factor type 1 and 2 toxins, remained unmodified in hha derivatives of strains FVL4 and CCB21.
我们从一株临床泌尿道致病性大肠杆菌分离株（FVL4菌株）和一株引起牛腹泻的野生大肠杆菌菌株（CCB21菌株）构建了hha衍生物，并分析了hha等位基因对这些菌株所表现出的不同毒力因子表达的影响。溶血素和Vir抗原的表达在hha突变体中发生了改变。FVL4菌株产生的溶血素在低温和高渗透压条件下均受到抑制，而hha等位基因导致在这些条件下溶血素产量显著增加。此外，hha突变体中Vir黏附素的低温敏感表达发生了改变，这些突变体能够在低温下表达这种黏附素。其他毒力因子，如1型和2型细胞毒性坏死因子毒素的表达，在FVL4和CCB21菌株的hha衍生物中未发生改变。
