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Atmospheric Deposition and Biogeochemistry of Mercury and other Trace Contaminants in Aquatic Ecosystems, Final Project Report Part II: Mercury Studies 2002-2004
This report summarizes the mercury studies, and has two main objectives. First to summarize the findings of biogeochemical investigations in the Devils Lake watershed during 2002, 2003, and 2004 and compare them to findings for other lakes. The second objective is to compile and tabulate the large amount of mercury data that are collected so that they will be usefule to the Tribe in future studies
GASCan 2 payload integration
This project, conducted in cooperation with the NASA Advanced Space Design Program, is part of an ongoing effort to place an experiment package into space. The goal of this project is to build and test flight-ready hardware that can be launched from the Space Shuttle. Get Away Special Canister 2 (GASCan 2) consists of three separate experiments. The Ionospheric Properties and Propagation Experiment (IPPE) determines effects of the ionosphere on radio wave propagation. The Microgravity Ignition experiment (MGI) tests the effects of combustion in a microgravity environment. The Rotational Fluid Flow experiment (RFF) examines fluid behavior under varying levels of gravity. This year the following tasks were completed: design of the IPPE antenna, X- and J-cell battery boxes, J-cell battery box enclosure, and structural bumpers; construction of the MGI canisters, MGI mounting brackets, IPPE antenna, and battery boxes; and the selection of the RFF's operating fluid and the analysis of the fluid behavior under microgravity test conditions
770-5 Chamber Specific Regulation of the Sarcoplasmic Reticulum Calcium ATPase Pump In Human Heart Failure
Alterations in the expression of Ca2+ channels have been described in failing human left ventricle, including down regulation of the ryanodine receptor (RyR)/Ca2+ release channel and the sarcoplasmic reticulum Ca2+ ATPase pump (SERCA) which are involved in excitation-contraction coupling and relaxation (Cir Res 71: 18, 1992). We previously reported chamber specific regulation of the RyR during end-stage human heart failure (Clin Res 42(2):166A. 1994). We investigated whether SERCA is also regulated in the other cardiac chambers during human heart failure. Total RNA and protein homogenates were isolated from the left and right atria (LA, RA) and left and right ventricles (LV, RV) obtained prospectively from 32 cardiac transplant patients and 4 normal controls. Messenger RNA (mRNA) levels of SERCA were quantified using Northern and slot blot hybridizations with a 1.6kb rat cardiac SERCA cDNA probe and normalized to 28S ribosomal levels. Protein levels of SERCA were quantified using enzyme-linked immunosorbent assays with monoclonal antibodies directed against dog cardiac SERCA. Northern analyses detected a single ≈4 kb mRNA in all regions. Compared to controls. SERCA mRNA expression in failing hearts was decreased in LV by 39% (p<0.005), unchanged in RV, and increased in LA by 255% (p<0.005) and in RA by 338% (p<0.025). Consistent with the mRNA data. immunodetectable levels of SERCA were also reduced in LV by 30% (p<0.05) and unchanged in RV; however, protein levels appeared unchanged or reduced in both atria in contrast to the mRNA. This is the first study reporting simultaneous measurements of SERCA mRNA and protein levels in the human heart. We conclude that chamber specific regulation of SERCA mRNA occurs during end-stage heart failure. corroborated by protein expression in the ventricles. Down regulations of SERCA may contribute to impaired relaxation and increased diastolic tone during heart failure
Correcting CDOM fluorescence measurements for temperature effects under field conditions in freshwaters
Ca2+ release by inositol 1,4,5-trisphosphate is blocked by the K+-channel blockers apamin and tetrapentylammonium ion, and a monoclonal antibody to a 63 kDa membrane protein: reversal of blockade by K+ ionophores nigericin and valinomycin and purification of the 63 kDa antibody-binding protein
High methylmercury in Arctic and subarctic ponds is related to nutrient levels in the warming eastern Canadian Arctic
Permafrost thaw ponds are ubiquitous in the eastern
Canadian Arctic, yet little information exists on their potential as
sources of methylmercury (MeHg) to freshwaters. They are
microbially active and conducive to methylation of inorganic
mercury, and are also affected by Arctic warming. This multiyear
study investigated thaw ponds in a discontinuous permafrost region
in the Subarctic taiga (Kuujjuarapik-Whapmagoostui, QC) and a
continuous permafrost region in the Arctic tundra (Bylot Island,
NU). MeHg concentrations in thaw ponds were well above levels
measured in most freshwater ecosystems in the Canadian Arctic
(>0.1 ng L−1). On Bylot, ice-wedge trough ponds showed
significantly higher MeHg (0.3−2.2 ng L−1) than polygonal
ponds (0.1−0.3 ng L−1) or lakes (<0.1 ng L−1). High MeHg was
measured in the bottom waters of Subarctic thaw ponds near
Kuujjuarapik (0.1−3.1 ng L−1). High water MeHg concentrations in thaw ponds were strongly correlated with variables
associated with high inputs of organic matter (DOC, a320, Fe), nutrients (TP, TN), and microbial activity (dissolved CO2 and
CH4). Thawing permafrost due to Arctic warming will continue to release nutrients and organic carbon into these systems and
increase ponding in some regions, likely stimulating higher water concentrations of MeHg. Greater hydrological connectivity
from permafrost thawing may potentially increase transport of MeHg from thaw ponds to neighboring aquatic ecosystems
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