Browsing by Author "Weiner, R. M."

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Adhesion of biofilms to inert surfaces: a molecular level approach directed at the marine environments
(1996-09) Baty, Ace M.; Frolund, B.; Geesey, Gill G.; Langille, S. E.; Quintero, Ernesto J.; Suci, Peter A.; Weiner, R. M.
Protein/ligand interactions involved in mediating adhesion between microorganisms and biological surfaces have been well‐characterized in some cases (e.g. pathogen/host interactions). The strategies microorganisms employ for attachment to inert surfaces have not been so clearly elucidated. An experimental approach is presented which addresses the issues from the point of view of molecular interactions occurring at the interface.
Adhesive extracellular polymers of hyphomonas mhs-3: interaction of polysaccharides and proteins
(1995-12) Suci, Peter A.; Frolund, B.; Quintero, Ernesto J.; Weiner, R. M.; Geesey, Gill G.
The adsorption behavior of extracellular polymeric substances (EPS) from the marine bacterium Hyphomonas MHS‐3 was investigated using attenuated total reflection Fourier transform infrared (ATR/FT‐IR) spectrometry. The protein fraction of the crude EPS (EPSC) (propanol precipitated/extracted with EDTA) dominated the adsorption onto the germanium substratum. Removal of the Protease K accessible portion of the EPSC protein, and treatment with RNase and DNase, yielded a hygroscopic substance (EPSP) which contained at least one adhesive polysaccharide component. Conditioning the substratum with EPSC diminished adsorption of the polysaccharide fractions in EPSP; pre‐adsorbed EPSC protein was not displaced. The rate of EPSC adsorption on substrata conditioned with EPSP was slower than to clean germanium; however, the projected surface coverage of protein after long times, based on an empirical datafit, was the same as that for a clean substratum; the EPSC proteins did not displace the pre‐adsorbed adhesive polysaccharide fraction. SDS‐PAGE (Coomassie blue stain) revealed an extensive homology between proteins from cell lysates and EPSC proteins. However, distinct differences in the banding pattern suggested that proteins did not originate primarily from cell lysis during the extraction procedure. The results indicate that adhesive components of EPS, with respect to a hydrophilic surface (germanium), can be either protein or polysaccharide and that they may compete for interfacial binding sites.
Function of bacterial (hyphomonas spp.) capsular exopolymers in biofouling
(1997) Weiner, R. M.; Langille, S. E.; Geesey, Gill G.; Quintero, Ernesto J.
Influence of divalent cations and ph on adsorption of a bacterial polysaccharide adhesin
(1998-09) Bhosle, N.; Suci, Peter A.; Baty, Ace M.; Weiner, R. M.; Geesey, Gill G.
Hyphomonas MHS-3 (MHS-3) elaborates a diffuse capsular material, primarily composed of polysaccharide, which has been implicated to serve as the holdfast of this prosthecate marine bacterium. A purified polysaccharide (fr2ps) from this capsular material exhibits a relatively large affinity for (Ge), or more precisely for the Ge oxide surface film. In its natural habitat MHS-3 attaches to marine sediments. This suggests that molecular properties of fr2ps have evolved to render it adhesive toward mineral oxides. In order to characterize these molecular interactions, the effect of divalent cations and pH on the adsorption of fr2ps to Ge has been measured using attenuated total internal reflection Fourier transform infrared (ATR/FT-IR) spectroscopy. The effect of adsorption of fr2ps on the Ge oxide film has been investigated using X-ray photoelectron spectroscopy (XPS). The results indicate that divalent cations participate in binding of fr2ps to Ge oxide and that atomic size of the cation is important. Evidence for significant participation of hydrogen bonding to the oxide surface is lacking.
Influence of protein conditioning films on binding of a bacterial polysaccharide adhesin from hyphomonas mhs-3
(1996-09) Frolund, B.; Suci, Peter A.; Langille, S. E.; Weiner, R. M.; Geesey, Gill G.
A putative polysaccharide adhesin which mediates non‐specific attachment of Hyphomonas MHS‐3 (MHS‐3) to hydrophilic substrata has been isolated and partially characterized. A polysaccharide‐enriched portion of the extracellular polymeric substance (EPSP) from MHS‐3 was separated into four fractions using high performance size exclusion chromatography (HPSEC). Comparison of chromatograms of EPSP from MHS‐3 and a reduced adhesion strain (MHS‐3 rad) suggested that one EPSP fraction, which consisted of carbohydrate, served as an adhesin. Adsorption of this fraction to germanium (Ge) was investigated using attenuated total reflection Fourier transform infrared (ATR/FT‐IR) spectrometry. Binding curves indicated that the isolated fraction had a relatively high affinity for Ge when ranked against an adhesive protein from Mytilis edulis, mussel adhesive protein (MAP) and an acidic polysaccharide (alginate from Macrocystis pyrifera). Spectral features were used to identify the fraction as a polysaccharide previously reported to adsorb preferentially out of the EPSP mixture. Conditioning the Ge substratum with either bovine serum albumin (BSA) or MAP decreased the adsorption of the adhesive polysaccharide significantly. Conditioning Ge with these proteins also decreased adhesion of whole cells.
Polysaccharide-specific probes inhibit adhesion of hyphomonas rosenbergii strain vp-6 to hydrophilic surfaces
(2000-08) Langille, S. E.; Geesey, Gill G.; Weiner, R. M.
Biofilm formation commences with the adhesion of microorganisms to surfaces. Information regarding the initial bond between a bacterium and a solid surface is essential for devising methods to inhibit the onset of biofilm formation. Three different types of polysaccharide-specific probes, cationic metals, dyes, and lectins, were used to bind the exopolysaccharide of Hyphomonas rosenbergii, a budding, prosthecate marine bacterium. Probes, which specifically bind complex carbohydrates, inhibit the adhesion of H. rosenbergii to hydrophilic surfaces. These results suggest that the polysaccharide portion of H. rosenbergii capsular, extracellular polymeric-substance is involved in the primary adhesion process. Journal of Industrial Microbiology & Biotechnology (2000) 25, 81–85.