Browsing by Author "Baty, Ace 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.
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.
The adsorption of the mussel adhesive proteins of the marine mussel, Mytilus edulis, to polymer films
(Montana State University - Bozeman, College of Engineering, 1995) Baty, Ace M.
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, Somkiet
Chemical characterization of deposits associated with microbiologically influenced copper corrosion in potable water systems
(2002-04) Geesey, Gill G.; Baty, Ace M.; Bremer, Philip J.; Schamberger, P. C.; Henshaw, G. S.; Webster, Barbara J.; Wells, D. Bret
The internal surfaces of copper tubes, removed from potable water distribution systems in Australia and New Zealand, which experienced episodes of copper by-product release or "blue water," were evaluated by x-ray photoelectron spectroscopy (XPS) and dynamic secondary ion spectrometry (SIMS). Visual and microscopic inspection of the internal tube surface revealed a mosaic of deposits. Three distinct deposits were identified on the surface of tube recovered from a Grahamtown system in the Hunter Valley (HV) of Australia, whereas two distinct deposits were detected on the surface of tube retrieved from the Defense Scientific Establishment (DSE) facility in Auckland, NZ. XPSanalysis revealed the presence of organic nitrogen, with a C/N similar to living biomass, concentrated on the yellow green-surface deposit and the deposit-free area of tube from the HVsystem. In contrast, deposits and deposit-free areas on the tube from the DSE system contained no significant quantities of organic nitrogen. A secondary ion mass spectrometer (SIMS) depth profile of a corrosion deposit on the surface of tube from the HV system revealed a multi-layer structure, consisting of an organic carbon-enriched Cu(OH)2, Cu(OH)2CuCO3 layer on top of an organic carbon-depleted Cu2O layer. The structure and chemistry of the surface deposits on the HV tube were consistent with a mechanistic model involving growth of a copper oxide film under neutral or alkaline conditions modified by the presence and activities of surface-associated microorganisms. An alternative mechanism may be responsible for the copper by-product release from the tube in the DSE system, since significant quantities of organic nitrogen were not detected in deposits on tubes from this source. Based on the surface chemical data presented here, it is difficult to determine whether similar mechanisms were responsible for the copper by-product release associated with copper tube from these two different distribution systems. The results do suggests that previous models of copper surface film structure may not describe the range of reactions required to adequately explain copper by-product release under certain conditions.
Differentiation of chitinase-active and non-chitinase-active subpopulations of a marine bacterium during chitin degradation
(2000-08) Baty, Ace M.; Eastburn, Callie C.; Diwu, Zhenjun; Techkarnjanaruk, Somkiet; Goodman, Amanda E.; Geesey, Gill G.
The ability of marine bacteria to adhere to detrital particulate organic matter and rapidly switch on metabolic genes in an effort to reproduce is an important response for bacterial survival in the pelagic marine environment. The goal of this investigation was to evaluate the relationship between chitinolytic gene expression and extracellular chitinase activity in individual cells of the marine bacterium Pseudoalteromonas sp. strain S91 attached to solid chitin. A green fluorescent protein reporter gene under the control of the chiA promoter was used to evaluate chiA gene expression, and a precipitating enzyme-linked fluorescent probe, ELF-97-N-acetyl-b-D-glucosaminide, was used to evaluate extracellular chitinase activity among cells in the bacterial population. Evaluation of chiA expression and ELF-97 crystal location at the single-cell level revealed two physiologically distinct subpopulations of S91 on the chitin surface: one that was chitinase active and remained associated with the surface and another that was non-chitinase active and released daughter cells into the bulk aqueous phase. It is hypothesized that the surface-associated, non-chitinase-active population is utilizing chitin degradation products that were released by the adjacent chitinase-active populations for cell replication and dissemination into the bulk aqueous phase.
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.
Investigation of mussel adhesive protein adsorption on polystryene and poly(octadecyl methacrylate) using angle dependent xps, atr-ftir and afm
(1996-02) Baty, Ace M.; Suci, Peter A.; Tyler, Bonnie J.; Geesey, Gill G.
The irreversible adsorption of mussel adhesive proteins (MAP) from the marine mussel Mytilus edulishas been investigated on polystyrene (PS) and poly(octadecyl methacrylate) (POMA) surfaces using angle resolved X-ray photoelectron spectroscopy (XPS), attenuated total reflection Fourier transform infrared (ATR-FTIR) spectrometry, and atomic force microscopy (AFM). Angle resolved XPS was used to quantify the elemental composition with depth of the upper 90 Å of the surface, and AFM was used to obtain the surface topography. The adsorption pattern of MAP, revealed by AFM images, is distinctly different on the two polymer surfaces and suggests that the substratum influences protein adhesion. The depth profiles of MAP, obtained from angle resolved XPS, show differences in nitrogen composition with depth for MAP adsorbed to PS and POMA. Infrared spectra of hydrated adsorbed MAP revealed significant differences in the amide III region and in two bands which may originate from residues in the tandemly repeated sequences of MAP. This data demonstrates that the chemistry of the polymer film that is present at the protein–polymer interface can influence protein–protein and protein–surface interactions.
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.
Spatial and temporal variations in chitinolytic gene expression and bacterial biomass production during chitin degradation
(2000-08) Baty, Ace M.; Eastburn, Callie C.; Techkarnjanaruk, Somkiet; Goodman, Amanda E.; Geesey, Gill G.
Growth of the chitin-degrading marine bacterium S91 on solid surfaces under oligotrophic conditions was accompanied by the displacement of a large fraction of the surface-derived bacterial production into the flowing bulk aqueous phase, irrespective of the value of the surface as a nutrient source. Over a 200-h period of surface colonization, 97 and 75% of the bacterial biomass generated on biodegradable chitin and a nonnutritional silicon surface, respectively, detached to become part of the free-living population in the bulk aqueous phase. Specific surface-associated growth rates that included the cells that subsequently detached from the substrata varied depending on the nutritional value of the substratum and during the period of surface colonization. Specific growth rates of 3.79 and 2.83 day-1 were obtained when cells first began to proliferate on a pure chitin film and a silicon surface, respectively. Later, when cell densities on the surface and detached cells as CFU in the bulk aqueous phase achieved a quasi-steady state, specific growth rates decreased to 1.08 and 0.79 day-1 on the chitin and silicon surfaces, respectively. Virtually all of the cells that detached from either the chitin or the cilicon surfaces and the majority of cells associated with the chitin surface over the 200-h period of surface colonization displayed no detectable expression of the chitin-degrading genes chiA and chiB. Cells displaying high levels of chiA-chiB expression were detected only on the chitin surface and then only clustered in discrete areas of the surface. Surface-associated, differential gene expression and displacement of bacterial production from surfaces represent adaptations at the population level that promote efficient utilization of the limited resources and dispersal of progeny to maximize access to new sources of energy and maintenance of the population.