Документ взят из кэша поисковой машины. Адрес оригинального документа : http://kodomo.cmm.msu.ru/~bnagaev/Term2/data_banks/PubMed/abstract.txt Дата изменения: Thu Sep 9 23:55:25 2010 Дата индексирования: Sat Sep 11 21:53:08 2010 Кодировка:

Microbial Food Safety Research Unit, Eastern Regional Research Center,
Agricultural Research Service, U.S. Department of Agriculture, Wyndmoor,
Pennsylvania; Bacterial Diseases of Livestock Research Unit, National Animal
Disease Center, Ames, Iowa; and Department of Diagnostic Medicine/Pathobiology,
College of Veterinary Medicine, Kansas State University, 1600 Denison Ave.,
Manhattan, Kansas.

In Escherichia coli O157:H7 strain ATCC 43895, a guanine to thymine transversion
in the csgD promoter created strain 43895OR. Strain 43895OR produces an abundant
extracellular matrix rich in curli fibers, forms biofilm on solid surfaces,
invades cultured epithelial cells, and is more virulent in mice than strain
43895. In this study we compared the formic acid-soluble proteins expressed by
strains 43895OR and 43895 using one-dimensional SDS-PAGE analysis and identified
two differentially expressed proteins. A 17-kDa protein unique to strain 43895OR
was identified from MALDI-TOF combined MS+MS/MS spectra as the curli subunit
encoded by csgA. A <10-kDa protein, more highly expressed in strain 43895, was
identified as the Lpp lipoprotein. Mutants of strain 43895OR with disruption of
lpp, csgA, and both lpp/csgA were created and tested for changes in phenotype and
function. The results of this study show that both Lpp and CsgA contribute to the
observed colony morphology, Congo red binding, motility, and biofilm formation.
We also show that both CsgA and Lpp were required by strain 43895OR for the
invasion of cultured HEp-2 cells. These studies suggest that in strain 43895OR,
the murein lipoprotein, Lpp, indirectly regulates CsgA expression through the
CpxAR system by a post-transcriptional mechanism.