Scholarly Work - Center for Biofilm Engineering
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/9335
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Item Use of dcode system to detect the food-borne bacterial pathogen listeria monocytogenes(1998) Schmolker, N.; van Ommen Kloeke, F.; Geesey, Gill G.Item 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.Item Bacterial colonization of artificial substrate in the vicinity of deep-sea hydrothermal vents(1998-06) Guezennec, J.; Ortega-Morales, O.; Raguenes, G.; Geesey, Gill G.Artificial substrata of different material composition were deployed at deep-sea hydrothermal areas on the Mid-Atlantic Ridge for exposure times ranging from 1 to 12 days. After 4 days of exposure, a very thick but loosely-bound biofilm formed on all surfaces. Two bacterial morphotypes dominated the attached microbial community: rod-shaped bacteria sometimes several cell layers thick and large filamentous forms attached to the substratum at one end of the filament. Quantitative extraction of biofilm lipids associated with the substratum surface indicated the accumulation of a large amount of bacterial biomass after 4 days of exposure for all substrata. Microbial biomass accumulated at different rates on the different substrata. The greatest biomass was associated with 316L stainless steel and titanium substrata. Polar lipid fatty acid (PLFA) analysis of lipid extracts contained signatures of sulfate reducing bacteria and fatty acids (FA) previously reported in filamentous sulfur-oxidizing bacteria. The results demonstrate rapid in situ colonization of artificial substrata by hydrothermal vent microbial populations irrespective of the nature of the substratum.Item Observations and interpretations of the performance of engineered materials for containment of spent nuclear fuels during interim wet storage: a need for improved corrosion monitoring capabilities?(1998) Geesey, Gill G.; Zhang, Hong-Ji; Suci, Peter A.; Davidson, D.; Baty, Ace M.; van Ommen Kloeke, F.Item Function of bacterial (hyphomonas spp.) capsular exopolymers in biofouling(1997) Weiner, R. M.; Langille, S. E.; Geesey, Gill G.; Quintero, Ernesto J.Item Characterization of extracellular chitinolytic activity in biofilms(2001) Baty, Ace M.; Diwu, Zhenjun; Dunham, G.; Eastburn, Callie C.; Geesey, Gill G.; Goodman, Amanda E.; Suci, Peter A.; Techkarnjanaruk, SomkietItem Combined light microscopy and attenuated total reflection fourier transform infrared spectroscopy for integration of biofilm structure, distribution, and chemistry at solid-liquid interfaces(1997-11) Suci, Peter A.; Siedlecki, Kevin J.; Palmer, R. J.; White, D. C.; Geesey, Gill G.Item Adsorption of adhesive proteins from the marine mussel, mytilus edulis, on polymer films in the hydrated state using angle dependent x-ray photoelectron spectroscopy and atomic force microscopy(1997-10) Baty, Ace M.; Leavitt, P. K.; Siedlecki, C. A.; Tyler, Bonnie J.; Suci, Peter A.; Marchant, R. E.; Geesey, Gill G.The adsorption of mussel adhesive protein (MAP) from the marine mussel Mytilus edulis has been investigated on polystyrene (PS) and poly(octadecyl methacrylate) (POMA) surfaces using angle dependent X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). AFM images previously published in the dehydrated state using contact mode are compared with images acquired in the hydrated state using fluid Tapping Mode to assess the contribution that hydration has on the architecture of the adsorbed proteins. To further characterize the adsorbed protein layer, XPS analysis was performed at liquid nitrogen (LN2) temperature without dehydrating the samples and at room temperature after the surfaces were dehydrated. The differences observed upon dehydration can be attributed to the strength of the interactions between MAP and the two surfaces. The AFM and XPS data indicate that adsorbed MAP is stabilized on the surface of the PS through interactions that prevent the protein layer from being disrupted upon dehydration. The adsorbed MAP on the POMA surface is representative of a loosely bound protein layer that becomes highly perturbed upon dehydration.Item Determination of the feasibility of using attenuated total reflectance fourier transform-infrared spectroscopy to evaluate thermal ageing of enamel-coated magnet wire(1997-01) Bremer, Philip J.; Geesey, Gill G.A study was initiated to determine the feasibility of employing attenuated total reflectance Fourier transform–infrared spectroscopy (ATR/FT–IR) to detect changes resulting from thermal ageing in the enamel of copper magnet wire. Polyamideimide (SX-81002) was cured on a zinc selenide (ZnSe) internal reflection element (IRE) coated with a thin film of metallic copper. The coated IRE was inserted in a Circle cell housed in a heating jacket and maintained at 250°C on the optical bench of an infrared spectrometer to simulate thermal ageing of enamel-coated magnet wire. Evaluation of the infrared spectra in the fingerprint region suggested that the polymer experienced chemical degradation within a 23 day period of thermal ageing. Through comparisons with controls containing no copper coatings, and ageing studies carried out at 28°C, it was determined that ageing at elevated temperature caused more pronounced chemical changes in the polymer than did exposure to the copper. These results indicate that ATR/FT–IR may be a useful tool to detect enamel fatigue after a short period of thermal ageing.Item Development of an artificial biofilm to study the effects of a single microcolony on mass transport(1996-07) Abrahamson, Michael T.; Lewandowski, Zbigniew; Geesey, Gill G.; Skjak-Braek, G.; Strand, W.Alginate harvested from a mucoid strain of Pseudomonas aeruginosa, grown on YTG agar plates, was used to develop an artificial biofilm. The alginate was sterilized and fixed to a glass slide where it served as the biofilm matrix. High densities of P. aeruginosa were injected into specific locations within the alginate matrix to represent microcolonies similar to those found in natural biofilms. Dissolved oxygen microelectrodes, with tip diameters of 10 μm, were constructed and used to measure oxygen profiles through the artificial biofilm. Using mathematical models the kinetic parameters for microbial respiration were extracted from the profiles. The activity of immobilized microorganisms was monitored and the dynamics of dissolved oxygen transport to a single microcolony was evaluated.