Linked Life Data

12099808

Source:http://linkedlifedata.com/resource/pubmed/id/12099808

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2002-7-8
pubmed:abstractText
The heterogeneity in bacterial surface macromolecules was probed by examining individual macromolecules on the surface of Pseudomonas putida KT2442 via single-molecule force spectroscopy (SMFS). Using an atomic force microscope (AFM), the silicon nitride tip was brought into contact with biopolymer molecules on bacterial cells and these macromolecules were stretched. Force-extension measurements on different bacterial cells showed a range of adhesion affinities and polymer lengths. However, substantial heterogeneity was also observed in the force-extension curves on a single bacterium. A given bacterium has biopolymers that range in size from tens to hundreds of nanometers, with adhesion affinities for the AFM tip from nearly zero to greater than 1 nN. A distribution of polymer sizes was confirmed by size-exclusion chromatography. The freely jointed chain (FJC) model for polymer elasticity was applied to individual force-extension curves in order to estimate the contour lengths and segment lengths of the polymer chains. A range of segment lengths was obtained using the FJC model, from 0.154-0.45 nm in water, 0.154-0.32 nm in 0.01 M KCl, and 0.154-0.65 nm in 0.1 M KCl. The modeling confirms that the heterogeneity in biopolymers is more than a matter of differences in molecular weights, since a range of stiffnesses (segment lengths) was also observed. The effect of salt concentration on biopolymer conformation and adhesion was also explored. While the biopolymers were flexible in all solvents, they were slightly more extended in water than in either of the salt solutions (0.01 and 0.1 M KCl). The adhesion of polysaccharides with the AFM tip was not dependent on salt concentration, because the polymers were not highly charged and heterogeneity overwhelmed any trends that could be observed in adhesion with respect to solution ionic strength. These experiments indicate that heterogeneity in biopolymer properties on an individual bacterium and within a population of bacterial cells may be much greater than previously believed and should be incorporated into models of bacterial adhesion.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
1525-7797
pubmed:author
pubmed:issnType
Print
pubmed:volume
3
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
661-7
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:articleTitle
Heterogeneity in bacterial surface polysaccharides, probed on a single-molecule basis.
pubmed:affiliation
Department of Chemical Engineering, Worcester Polytechnic Institute, 100 Institute Road, Worcester, Massachusetts 01609, USA. terric@wpi.edu
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't