Browsing by Author "Frolund, B."

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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.
Deflocculation of activated sludge by the dissimilatory fe(III)-reducing bacterium Shewanella alga BrY
(1996-04) Caccavo, Frank; Frolund, B.; Van Ommen Kloeke, Fintan; Nielsen, P. H.
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.
Monitoring of microbial souring in chemically treated, produced-water biofilm systems using molecular techniques
(2005-04) Kjellerup, B. V.; Veeh, Richard Harold; Sumithrarathne, P.; Thomsen, T. R.; Buckingham-Meyer, Kelli; Frolund, B.; Sturman, Paul J.
The identification of bacteria in oil production facilities has previously been based on culture techniques. However, cultivation of bacteria from these often-extreme environments can lead to errors in identifying the microbial community members. In this study, molecular techniques including fluorescence in situ hybridization, PCR, denaturing gradient gel electrophoresis, and sequencing were used to track changes in bacterial biofilm populations treated with nitrate, nitrite, or nitrate+molybdate as agents for the control of sulfide production. Results indicated that nitrite and nitrate+molybdate reduced sulfide production, while nitrate alone had no effect on sulfide generation. No long-term effect on sulfide production was observed. Initial sulfate-reducing bacterial numbers were not influenced by the chemical treatments, although a significant increase in sulfate-reducing bacteria was observed after termination of the treatments. Molecular analysis showed a diverse bacterial population, but no major shifts in the population due to treatment effects were observed.