J. Otto et al., Adhesion of type 1-fimbriated Escherichia coli to abiotic surfaces leads to altered composition of outer membrane proteins, J BACT, 183(8), 2001, pp. 2445-2453
Phenotypic differences between planktonic bacteria and those attached to ab
iotic surfaces exist, but the mechanisms involved in the adhesion response
of bacteria are not well understood. By the use of two-dimensional (2D) pol
yacrylamide gel electrophoresis, we have demonstrated that attachment of Es
cherichia coli to abiotic surfaces leads to alteration in the composition o
f outer membrane proteins. A major decrease in the abundance of resolved pr
oteins was observed during adhesion of type l-fimbriated E. coli strains, w
hich was at least partly caused by proteolysis. Moreover, a study of fimbri
ated and nonfimbriated mutants revealed that these changes were due mainly
to type 1 fimbria-mediated surface contact and that only a few changes occu
rred in the outer membranes of nonfimbriated mutant strains. Protein synthe
sis and proteolytic degradation were involved to different extents in adhes
ion of fimbriated and nonfimbriated cells. While protein synthesis appeared
to affect adhesion of only the nonfimbriated strain, proteolytic activity
mostly seemed to contribute to adhesion of the fimbriated strain. Using mat
rix-assisted laser desorption ionization-time of flight mass spectrometry,
six of the proteins resolved by 2D analysis were identified as BtuB, EF-Tu,
OmpA, OmpX, Sip, and TolC. While the first two proteins were unaffected by
adhesion, the levels of the last four were moderately to strongly reduced.
Based on the present results, it may be suggested that physical interactio
ns between type 1 fimbriae and the surface are part of a surface-sensing me
chanism in which protein turnover may contribute to the observed change in
composition of outer membrane proteins. This change alters the surface char
acteristics of the cell envelope and may thus influence adhesion.