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Your search keyword '"Higgins, Christopher"' showing total 166 results
Start Over Author "Higgins, Christopher" Publisher american chemical society
166 results on '"Higgins, Christopher"'

22. The vinblastine binding site adopts high- and low-affinity conformations during a transport cycle of P-glycoprotein

Author

Martin, Catherine, Higgins, Christopher F., and Callaghan, Richard

Subjects
Vinblastine -- Physiological aspects, Binding sites (Biochemistry) -- Analysis, Glycoproteins -- Physiological aspects, Conformational analysis -- Research, Biological sciences, Chemistry
Abstract

Results show that the radioligand vinblastine exhibits high affinity interaction with a single class of binding site on the ABC transporter P-glycoprotein. The low-affinity binding is brought about by AMP-PNP with no alteration in the binding capacity. Furthermore, the binding site affinity is altered by one single nucleotide change.

Published
2001

23. Drug binding sites on P-glycoprotein are altered by ATP binding prior to nucleotide hydrolysis

Author

Martin, Catherine, Berridge, Georgina, Mistry, Prakash, Higgins, Christopher, Charlton, Peter, and Callaghan, Richard

Subjects
Drug resistance -- Research, Glycoproteins -- Research, Binding sites (Biochemistry) -- Research, Biological sciences, Chemistry
Abstract

ATP binding to P-glycoprotein initiates the conformational change in the drug-binding site. P-glycoprotein makes cancer cells resistant to drugs by pumping the drug out of the cell.

Published
2000

35. Organic carbon amendments for enhanced biological attenuation of trace organic contaminants in biochar-amended stormwater biofilters

Author

Ulrich, Bridget A., Vignola, Marta, Edgehouse, Katelynn, Werner, David, and Higgins, Christopher P.

Subjects
fungi, QD, complex mixtures
Abstract

This study sought to evaluate how dissolved organic carbon (DOC) affects attenuation of trace organic contaminants (TOrCs) in biochar-amended stormwater biofilters. It was hypothesized that (1) DOC-augmented runoff would demonstrate enhanced TOrC biodegradation and (2) biochar-amended sand bearing DOC-cultivated biofilms would achieve enhanced TOrC attenuation due to sorptive retention and biodegradation. Microcosm and column experiments were conducted utilizing actual runoff, DOC from straw and compost, and a suite of TOrCs. Biodegradation of TOrCs in runoff was more enhanced by compost DOC than straw DOC (particularly for atrazine, prometon, benzotriazole, and fipronil). 16S rRNA gene quantification and sequencing revealed that growth-induced microbial community changes were, among replicates, most consistent for compost-augmented microcosms and least consistent for raw runoff microcosms. Compost DOC most robustly enhanced utilization of TOrCs as carbon substrates, possibly due to higher residual nutrient levels upon TOrC exposure. Sand columns containing just 0.5 wt % biochar maintained sorptive TOrC retention in the presence of compost-DOC-cultivated biofilms, and TOrC removal was further enhanced by biological activity. Overall, these results suggest that coamendment with biochar and compost may robustly enhance TOrC attenuation in stormwater biofilters, a finding of significance for efforts to mitigate the impacts of runoff on water quality.

Published
2017

39. Reconnaissance of Mixed Organic and Inorganic Chemicals in Private and Public Supply Tapwaters at Selected Residential and Workplace Sites in the United States.

Author

Bradley, Paul M., Kolpin, Dana W., Romanok, Kristin M., Smalling, Kelly L., Focazio, Michael J., Brown, Juliane B., Cardon, Mary C., Carpenter, Kurt D., Corsi, Steven R., DeCicco, Laura A., Dietze, Julie E., Evans, Nicola, Furlong, Edward T., Givens, Carrie E., Gray, James L., Griffin, Dale W., Higgins, Christopher P., Hladik, Michelle L., Iwanowicz, Luke R., and Journey, Celeste A.

Published
2018
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47. Enhanced Biofilm Production by a Toluene-Degrading Rhodococcus Observed after Exposure to Perfluoroalkyl Acids.

Author

Weathers, Tess S., Higgins, Christopher P., and Sharp, Jonathan O.

Subjects
*BIOFILMS, *RHODOCOCCUS, *NOCARDIACEAE, *ALKYLBENZENES, *GROUNDWATER
Abstract

This study focuses on interactions between aerobic soil-derived hydrocarbon degrading bacteria and a suite of perfluorocarboxylic adds and perfluoroalkylsulfonates that are found in aqueous film-forming foams used for fire suppression. No effect on toluene degradation rate or induction time was observed when active cells of Rhodococcus jostii strain RHA1 were exposed to toluene and a mixture of perfluoroalkyl adds (PFAAs) including perfluorooctanoic add (PFOA) and perfluorooctanesulfonate (PFOS) at concentrations near the upper bounds of groundwater relevance ( 11 PFAAs at 10 mg/L each). However, exposure to aqueous PFAA concentrations above 2 mg/L (each) was assodated with enhanced aggregation of bacterial cells and significant increases in extracellular polymeric substance production. Flocculation was only observed during exponential growth and not elicited when PFAAs were added to resting incubations; analogous flocculation was also observed in soil enrichments. Aggregation was accompanied by 2- to 3-fold upregulation of stress-assodated genes, sigF3 and prmA, during growth of this Rhodococcus in the presence of PFAA. These results suggest that biological responses, such as microbial stress and biofilm formation, could be more prominent than suppression of co-contaminant biodegradation in subsurface locations where poly- and perfluoroalkyl substances occur with hydrocarbon fuels. [ABSTRACT FROM AUTHOR]

Published
2015
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