Torres Alfredo G, Milflores-Flores Lorena, Garcia-Gallegos J Gerardo, Patel Shilpa D, Best Angus, La Ragione Roberto M, Martinez-Laguna Ygnacio, Woodward Martin J
Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555-1070, USA.
Int J Med Microbiol. 2007 Jun;297(3):177-85. doi: 10.1016/j.ijmm.2007.01.005. Epub 2007 Mar 13.
The ability of Escherichia coli O157:H7 to colonize the intestinal epithelia is dependent on the expression of intimin and other adhesins. The chromosome of E. coli O157:H7 carries two loci encoding long polar fimbriae (LPF). These fimbriae mediate adherence to epithelial cells and are associated with colonization of the intestine. In order to increase our knowledge about the conditions controlling their expression and their role in colonization of an animal model, the environmental cues that promote expression of lpf genes and the role of E. coli O157:H7 LPF in intestinal colonization of lambs were investigated. We found that expression of lpf1 was regulated in response to growth phase, osmolarity, and pH; that lpf2 transcription was stimulated during late exponential growth and iron depletion; and that LPF impacts the ability of E. coli O157:H7 to persist in the intestine of infected 6-week-old lambs.
大肠杆菌O157:H7定殖于肠道上皮的能力取决于紧密黏附素和其他黏附素的表达。大肠杆菌O157:H7的染色体携带两个编码长极毛（LPF）的基因座。这些菌毛介导与上皮细胞的黏附，并与肠道定殖有关。为了增加我们对控制其表达的条件及其在动物模型定殖中作用的了解，研究了促进lpf基因表达的环境信号以及大肠杆菌O157:H7 LPF在羔羊肠道定殖中的作用。我们发现，lpf1的表达受生长阶段、渗透压和pH值的调节；lpf2转录在指数生长后期和铁缺乏时受到刺激；并且LPF影响大肠杆菌O157:H7在感染的6周龄羔羊肠道中持续存在的能力。
