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The EU Water Framework Directive (WFD) requirement that all surface water bodies achieve good ecological status is still a goal for many regulatory authorities in England and Wales. This paper describes field and laboratory studies designed to identify metal contaminant loadings and their distributions within water bodies located in the Lower Lee catchment (London, UK). Water and sediment samples have been collected from increasingly urbanised sites on the River Lee and its main tributaries over a two-year period with samples analysed for total concentrations of cadmium, copper, lead, mercury, nickel, tin, and zinc. Complimentary batch tests indicate a positive relationship between aqueous metal concentrations and the batch test-derived sediment metal release data, particularly during wet weather events. Field data indicate a dynamic relationship between water and sediment concentrations with both being capable of exceeding relevant environmental quality standards/sediment quality guidelines at all sites. Mean sediment metal concentrations across all sites were found to be highest for Cu (141.1 ± 111.0 µg g−1), Pb (175.7 ± 83.0 µg g−1), and Zn (499.9 ± 264.7 µg g−1) with Zn demonstrating elevated mean water concentrations (17.2 ± 13.8 µg L−1) followed by Ni (15.6 ± 11.4 µg L−1) and Cu (11.1 ± 17.8 µg L−1).
Lian Lundy; Luciana Alves; Michael Revitt; Dirk Wildeboer. Metal Water-Sediment Interactions and Impacts on an Urban Ecosystem. International Journal of Environmental Research and Public Health 2017, 14, 722 .
AMA StyleLian Lundy, Luciana Alves, Michael Revitt, Dirk Wildeboer. Metal Water-Sediment Interactions and Impacts on an Urban Ecosystem. International Journal of Environmental Research and Public Health. 2017; 14 (7):722.
Chicago/Turabian StyleLian Lundy; Luciana Alves; Michael Revitt; Dirk Wildeboer. 2017. "Metal Water-Sediment Interactions and Impacts on an Urban Ecosystem." International Journal of Environmental Research and Public Health 14, no. 7: 722.
Chronic non-healing wounds are a major health problem with resident bacteria strongly implicated in their impaired healing. A rapid-screen to provide detailed knowledge of wound bacterial populations would therefore be of value and help prevent unnecessary and indiscriminate use of antibiotics—a process associated with promoting antibiotic resistance. We analysed chronic wound fluid samples, which had been assessed for microbial content, using 20 different fluorescent labelled peptide substrates to determine whether protease activity correlated with the bacterial load. Eight of the peptide substrates showed significant release of fluorescence after reaction with some of the wound samples. Comparison of wound fluid protease activities with the microbiological data indicated that there was no correlation between bacterial counts and enzyme activity for most of the substrates tested. However, two of the peptide substrates produced a signal corresponding with the microbial data revealing a strong positive correlation with Pseudomonas aeruginosa numbers. This demonstrated that short fluorescent labelled peptides can be used to detect protease activity in chronic wound fluid samples. The finding that two peptides were specific indicators for the presence of P. aeruginosa may be the basis for a diagnostic test to determine wound colonisation by this organism.
D. Wildeboer; K. E. Hill; F. Jeganathan; David Williams; A. D. Riddell; P. E. Price; David Thomas; P. Stephens; R. A. Abuknesha; Robert Price. Specific protease activity indicates the degree of Pseudomonas aeruginosa infection in chronic infected wounds. European Journal of Clinical Microbiology & Infectious Diseases 2012, 31, 2183 -2189.
AMA StyleD. Wildeboer, K. E. Hill, F. Jeganathan, David Williams, A. D. Riddell, P. E. Price, David Thomas, P. Stephens, R. A. Abuknesha, Robert Price. Specific protease activity indicates the degree of Pseudomonas aeruginosa infection in chronic infected wounds. European Journal of Clinical Microbiology & Infectious Diseases. 2012; 31 (9):2183-2189.
Chicago/Turabian StyleD. Wildeboer; K. E. Hill; F. Jeganathan; David Williams; A. D. Riddell; P. E. Price; David Thomas; P. Stephens; R. A. Abuknesha; Robert Price. 2012. "Specific protease activity indicates the degree of Pseudomonas aeruginosa infection in chronic infected wounds." European Journal of Clinical Microbiology & Infectious Diseases 31, no. 9: 2183-2189.
Bacterial proteases, Type XXIV from Bacillus licheniformens and Type XIV from Streptomyces griseus, were used to investigate the utility and optimisation of a solid phase assay for proteases, using immunoglobulin proteins as substrates. Immunoglobulins IgA and IgG were adsorbed on to surfaces of ELISA plates and exposed to various levels of the bacterial proteases which led to digestion and desorption of proportional amounts of the immunoglobulins. The assay signal was developed by measuring the remaining proteins on the polystyrene surface with appropriate enzyme-labelled anti-immunoglobulin reagents. The assay was fully optimised in terms of substrate levels employing ELISA techniques to titrate levels of adsorbed substrates and protease analytes. The critical factor which influences assay sensitivity was found to be the substrate concentration, the levels of adsorbed immunoglobulins. The estimated detection limits for protease XXIV and XIV were 10 μ units/test and 9 μ units/test using IgA as a substrate. EC50 values were calculated as 213 and 48 μ units/test for each protease respectively. Using IgG as a substrate, the estimated detection limits were 104 μ units/test for protease XXIV and 9 μ units/test for protease XIV. EC50 values were calculated at 529 and 28 μ units/test for protease XXIV and XIV respectively.\ud \ud The solid phase protease assay required no modification of the substrates and the adsorption step is merely simple addition of immunoglobulins to ELISA plates. Adsorption of the immunoglobulins to polystyrene enabled straightforward separation of reaction mixtures prior to development of assay signal. The assay exploits the advantages of the technical facilities of ELISA technology and commercially available reagents enabling the detection and measurement of a wide range of proteases. However, the key issue was found to be that in order to achieve the potential performance of the simple assay, optimisation of the method was essential
Ramadan A. Abuknesha; Fiona Jeganathan; Dirk Wildeboer; Robert G. Price. Optimisation of the detection of bacterial proteases using adsorbed immunoglobulins as universal substrates. Talanta 2010, 81, 1237 -1244.
AMA StyleRamadan A. Abuknesha, Fiona Jeganathan, Dirk Wildeboer, Robert G. Price. Optimisation of the detection of bacterial proteases using adsorbed immunoglobulins as universal substrates. Talanta. 2010; 81 (4-5):1237-1244.
Chicago/Turabian StyleRamadan A. Abuknesha; Fiona Jeganathan; Dirk Wildeboer; Robert G. Price. 2010. "Optimisation of the detection of bacterial proteases using adsorbed immunoglobulins as universal substrates." Talanta 81, no. 4-5: 1237-1244.
Fluorescent antibody protein (IgG) was attached to the surface of an integrated optical glass waveguide chip via specific binding to a covalently attached hapten and used as a substrate for the measurement of protease activities. Exposure of the optical chip to proteases resulted in digestion of the bound fluorescent antibody molecules and proportional decrease in the detectable fluorescence resulting from loss of fluorescence from the evanescent field. The bound fluorescent antibody protein was used as a unique universal protease substrate in which the combined biological activity and fluorescence signal were the basis of measurement. The action of proteases was monitored in real-time mode where the gradual decrease in evanescent fluorescence was recorded. The chip was regenerated by complete digestion of the antibody substrate by excess pepsin and recharged by incubation with a fresh sample of the labelled antibody. The biosensor was used to detect activity of several proteases including a bacterial protease preparation, Pronase E. The linear range of measurable Pronase E activity was from 0.03 to 2 units/mL. A measurement cycle took 40 min for samples with high protease concentration (≥0.5 units/mL), when the concentration of the protease was less measurement times up to 100 min were required. The method demonstrates the principle of a new mode of real-time biosensing of proteases. The modular integrated optical glass waveguide biosensor system used in this study is compact and controlled by a laptop computer and could easily be miniaturised and utilized as a true probe device for detecting proteases with potential applications in a wide range of areas including research, clinical diagnostics, biotechnology processing and food and detergent manufacturing industries.
Dirk Wildeboer; Pisu Jiang; Robert G. Price; Siyuan Yu; Fiona Jeganathan; Ramadan A. Abuknesha. Use of antibody–hapten complexes attached to optical sensor surfaces as a substrate for proteases: Real-time biosensing of protease activity. Talanta 2010, 81, 68 -75.
AMA StyleDirk Wildeboer, Pisu Jiang, Robert G. Price, Siyuan Yu, Fiona Jeganathan, Ramadan A. Abuknesha. Use of antibody–hapten complexes attached to optical sensor surfaces as a substrate for proteases: Real-time biosensing of protease activity. Talanta. 2010; 81 (1-2):68-75.
Chicago/Turabian StyleDirk Wildeboer; Pisu Jiang; Robert G. Price; Siyuan Yu; Fiona Jeganathan; Ramadan A. Abuknesha. 2010. "Use of antibody–hapten complexes attached to optical sensor surfaces as a substrate for proteases: Real-time biosensing of protease activity." Talanta 81, no. 1-2: 68-75.