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Softness of the bacterial cell wall of Streptococcus mitis as probed by microelectrophoresis
Author(s) -
Rodríguez Virginia Vadillo,
Busscher Henk J.,
Norde Willem,
van der Mei Henny C.
Publication year - 2002
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/1522-2683(200207)23:13<2007::aid-elps2007>3.0.co;2-6
Subject(s) - microelectrophoresis , streptococcus mitis , electrophoresis , surface charge , adhesion , bacterial cellulose , chemistry , biophysics , fibril , ionic bonding , static electricity , zeta potential , materials science , chemical physics , nanotechnology , bacteria , chromatography , cellulose , composite material , biochemistry , streptococcus , biology , ion , organic chemistry , nanoparticle , electrical engineering , genetics , engineering
Chemical and structural complexity of bacterial cell surfaces complicate accurate quantification of cell surfaces properties. The presence of fibrils, fimbriae or other surface appendages on bacterial cell surfaces largely influence those properties and would therefore play a major function in interfacial phenomena as aggregation and adhesion. The electrophoretic softness and fixed charge density in the polyelectrolyte layer of nine Streptococcus mitis strains, usually carrying long sparsely distributed fibrils, were determined by the soft particle analysis using measured electrophoretic mobilities as a function of the ionic strength. In general, S. mitis cell surfaces are electrophoretically soft (1.0–2.5 nm) with a fixed negative charge density of –1.2 to –4.3×10 6 Cm –3 . Further, a comparison with surfaces of other bacterial strains that are reported to be soft indicates that the Ohshima soft layer model does not provide information on the surface morphology causing the softness. The most likely reason is that the electroosmotic flow occurs only in the very outer region of thick extracellular surface layers. Nevertheless, determining the surface softness is essential for proper characterization of the cell surface electrostatics.