Atmospheric Deposition: A Potential Source of Trace Metal Organic Complexing Ligands to the Marine Environment

The present study confirms the existence of rainwater and seawater soluble metal (Cu, Pb, Cd, Ni and Co) complexing organic ligands associated with end-member aerosol populations. The end member aerosols being representative of a European urban aerosol population (LUAP ¿ Liverpool Urban Aerosol Population), and an aerosol population representative of crustal dominated material (Mesh Saharan dust, collected off the west African coast). The investigations carried out by ACSV (adsorptive cathodic stripping voltammetry) clearly indicated that these end-members were a source of organic complexing ligands for all the considered metals. For LUAP Cu 26%, Pb 55%, Cd 36%, Ni 26% and Co 27% of the total seawater soluble fraction was ACSVnon-labile (i.e. that fraction of the dissolved metal which is released after UV irradiation) compared to the corresponding values for Saharan dust (Cu 59%, Pb 23%, Cd 56%, Ni 66%, Co 23%). From these studies it was apparent that the dissolution for all metals and their respective fractions in both seawater and artificial rainwater was a rapid process with no further release after ca. 30 minutes. The studies displayed for a number of the metals re-adsorption of ACSVnon-labile metal to the aerosol particulate surface (Co and Pb - Saharan / seawater; Co and Cd - LUAP / seawater) implying that different geochemical pathways are taken by different metal speciation fractions leading to potential differences in their marine residence times. Conditional formation stability constants and complexing capacities for Ni were determined for seawater after being equilibrated with both end member aerosols. Log K\u27NiL detected were 18.3 - 0.3 and 19.26 - 0.4 for LUAP and Saharan dust respectively. The equivalent complexing capacities were 1.0 - 0.1 nmol mg-1 and 0.038 - 0.005 nmol mg-1 respectively

Performance characteristics of a low-cost, field-deployable miniature CCD spectrometer

Miniature spectrometers incorporating array detectors are becoming a viable, low-cost option for field and process deployments. The performance characteristics of one such instrument are reported and compared with those of a conventional benchtop instrument. The parameters investigated were wavelength repeatability, photometric linearity, instrumental noise (photometric precision) and instrumental drift

Developing Field-Sim: Software to support fieldwork

This case study provides an insight on how small-scale projects can be used to provide effective learning products. It examines the evolution of a project from the initial rationale, through the development process and onto subsequent evaluation and modification. It also provides a good example of how educational developers/technologists can work, in partnership with lecturers, to provide solutions to learning and teaching issue

Analysis of Germline GLI1 Variation Implicates Hedgehog Signalling in the Regulation of Intestinal Inflammatory Pathways

Charlie Lees and colleagues identify a reduced-function variant of the hedgehog signaling pathway protein GLI1 that associates with inflammatory bowel disease, and investigate its role in a mouse model of colitis

Inflammatory bowel disease associates with proinflammatory potential of the immunoglobulin g glycome

BACKGROUND: Glycobiology is an underexplored research area in inflammatory bowel disease (IBD), and glycans are relevant to many etiological mechanisms described in IBD. Alterations in N-glycans attached to the immunoglobulin G (IgG) Fc fragment can affect molecular structure and immunological function. Recent genome-wide association studies reveal pleiotropy between IBD and IgG glycosylation. This study aims to explore IgG glycan changes in ulcerative colitis (UC) and Crohn's disease (CD). METHODS: IgG glycome composition in patients with UC (n = 507), CD (n = 287), and controls (n = 320) was analyzed by ultra performance liquid chromatography. RESULTS: Statistically significant differences in IgG glycome composition between patients with UC or CD, compared with controls, were observed. Both UC and CD were associated with significantly decreased IgG galactosylation (digalactosylation, UC: odds ratio [OR] = 0.71; 95% confidence interval [CI], 0.5–0.9; P = 0.01; CD: OR = 0.41; CI, 0.3–0.6; P = 1.4 × 10(−9)) and significant decrease in the proportion of sialylated structures in CD (OR = 0.46, CI, 0.3–0.6, P = 8.4 × 10(−8)). Logistic regression models incorporating measured IgG glycan traits were able to distinguish UC and CD from controls (UC: P = 2.13 × 10(−6) and CD: P = 2.20 × 10(−16)), with receiver–operator characteristic curves demonstrating better performance of the CD model (area under curve [AUC] = 0.77) over the UC model (AUC = 0.72) (P = 0.026). The ratio of the presence to absence of bisecting GlcNAc in monogalactosylated structures was increased in patients with UC undergoing colectomy compared with no colectomy (FDR-adjusted, P = 0.05). CONCLUSIONS: The observed differences indicate significantly increased inflammatory potential of IgG in IBD. Changes in IgG glycosylation may contribute to IBD pathogenesis and could alter monoclonal antibody therapeutic efficacy. IgG glycan profiles have translational potential as IBD biomarkers

Partial purification and characterization of a protein inhibitor of phosphoenolpyruvate carboxylase kinase

The activity of phosphoenolpyruvate carboxylase (PEPCase) kinase in leaf extracts increased markedly on dilution. This was shown to be caused by the presence of a protein that inhibits the kinase. The inhibitor protein was separated from the kinase and purified partially. It inhibited the kinase reversibly, presumably by a direct interaction; it was neither a protease nor a protein phosphatase. The amounts of kinase and inhibitor in leaves were estimated following separation by hydrophobic chromatography. The amount of inhibitor in the crassulacean acid metabolism plant Kalanchoë fedtschenkoi Hamet et Perrier was sufficient to inhibit the basal level of kinase activity present during the light period and the early stages of the dark period. Similarly, the amount of inhibitor in the C4 plant Zea mays L.was sufficient to inhibit the low amount of kinase activity present in the dark and at moderate light intensity. Analogous to the role of the protein inhibitor of mammalian cyclic AMP-dependent protein kinase, the function of the PEPCase kinase inhibitor may be to inhibit the basal level of kinase present in conditions under which rapid flux through PEPCase is not required

The release of copper-complexing ligands by the brown alga Fucus vesiculosus (Phaeophyceae) in response to increasing total copper levels

The growth of Fucus vesiculosus L, germlings in chemically defined culture media containing a range of Cu concentrations (20-1000 nM) was monitored simultaneously with measurement of the Cu speciation in the media by competitive equilibrium-adsorptive cathodic stripping voltammetry, Fucus vesiculosus germlings were found to exude Cu-complexing Ligands with conditional stability constants of the order of 1.6 x 10(11), Ligand concentrations increased with increasing total dissolved Cu concentrations (Cu-T) until a concentration of 500-800 neq Cu.L-1 was reached. Concentrations of the ligand exceeded Cu-T in treatments containing 20 and 100 nM Cu-T were similar to Cu-T in the 500-nM Cu treatment, but were less than Cu-T in the 1000-nM treatment. Therefore, [Cu2+] were calculated to be at concentrations of 10(-11) - 10(-10) M in the 20- and 100-nM treatments, 10(-9) M in the 500-nM treatment, and 10(-7) M in the 1000-nM treatment, Growth rates were lowest at Cu2+ concentration > 10(-9). These results are discussed within the context of the potential roles for exuded copper-complexing ligand