13 research outputs found

    Inferring marine distribution of Canadian and Irish Atlantic salmon (Salmo salar L.) in the North Atlantic from tissue concentrations of bio-accumulated Caesium 137

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    This is a pre-copy-editing, author-produced PDF of an article accepted for publication in ICES Journal of Marine Science following peer review. The definitive publisher-authenticated version “Spares A.D., Reader J.M., Stokesbury M.J.W., McDermott T., Zikovsky L., Avery T.S., Dadswell M.J. Inferring marine distribution of Canadian and Irish Atlantic salmon (Salmo salar L.) in the North Atlantic from tissue concentrations of bio-accumulated caesium 137. (2007) ICES Journal of Marine Science, 64 (2), pp. 394–404” is available online at: http://icesjms.oxfordjournals.org/content/64/2/394peer-reviewedAtlantic salmon returning from marine migrations to eastern Canada and western Ireland during 2002 and 2003 were analysed for tissue concentrations of bio-accumulated caesium 137 (137Cs). Salmon from Canadian and Irish waters demonstrated concentrations (0.20 ± 0.14 Bq kg-1 and 0.19 ± 0.09 Bq kg-1, mean ± s.d., respectively) suggesting similar oceanic feeding distributions during migration. Canadian aquaculture escapees had a similar mean tissue concentration (0.28 ± 0.22 Bq kg-1), suggesting migration with wild salmon. However, significantly higher concentrations in 1-sea-winter (1SW) escapees (0.43 ± 0.25 Bq kg-1) may alternatively suggest feeding within local estuaries. High concentrations in some Canadian 1SW salmon indicated trans-Atlantic migration. Low concentrations of Canadian multi-sea-winter (MSW) salmon suggested a feeding distribution in the Labrador and Irminger Seas before homeward migration, because those regions have the lowest surface water 137Cs levels. Estimates of wild Canadian and Irish salmon feeding east of the Faroes (~8oW) were 14.2% and 10.0% (1SW, 24.7% and 11.5%; MSW, 2.9% and 0.0%), respectively. We propose that most anadromous North Atlantic salmon utilize the North Atlantic Gyre for marine migration and should be classified as a single trans-Atlantic straddling stock

    Neutral Red Assay Modification to PreventCytotoxicity and Improve Repeatability Using E-63 Rat Skeletal Muscle Cells

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    Cellular uptake of neutral red dye (NR) is currently used as an indirect measure of viable cells in cultures. We used E-63 rat skeletal muscle cells to identify causes of NR assay variability and to develop modifications that substantially reduce it. Three methods of NR preparation and/or addition to cells were used. When NR medium was prepared, incubated overnight, and filtered to remove precipitates, the amount of dye precipitated varied greatly. Coefficients of variation (CVs) in NR uptake were greater than 25% between assays. Higher NR concentrations, longer incubation times, increased pH, and decreased temperature promoted NR precipitation in media. NR media prepared and filtered just prior to use or direct addition of prefiltered NR stock solution to cell cultures resulted in much smaller CVs between assays. NR was cytotoxic to E-63 rat muscle and primary quail myoblasts in a time-and concentration-dependent manner. NR exposure to E-63 cells for greater than 1.25 and 2 hr at 157 or 127 ÎŒg/ml, respectively, was associated with swelling and rupture of lysosomes. By contrast, there was no evidence of cytotoxicity when E-63 cells were exposed to NR for 1 hr at either 127 or 157 ÎŒg/ml. Primary quail myoblasts developed lysosomal swelling and ruptured more rapidly than E-63 cells when exposed to NR at either 127 or 157 ÎŒg/ml. For confluent 10-day cultures of E-63 cells exposed to NR at 127 ÎŒg/ml for 1 hr, the CVs within assay and between assays were 3.3-3.9% and 5.1%, respectively. For similarly exposed, actively replicating 3-day cultures of E-63 cells, the CVs within and between assays were 6.2-9.6% and 2.4%, respectively. NR uptake by the E-63 cells was linear with respect to viable cell number

    Munc13-2−/− baseline secretion defect reveals source of oligomeric mucins in mouse airways

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    Since the airways of control mouse lungs contain few alcian blue/periodic acid–Schiff's (AB/PAS)+ staining ‘goblet’ cells in the absence of an inflammatory stimulus such as allergen sensitization, it was surprising to find that the lungs of mice deficient for the exocytic priming protein Munc13-2 stain prominently with AB/PAS under control conditions. Purinergic agonists (ATP/UTP) stimulated release of accumulated mucins in the Munc13-2-deficient airways, suggesting that the other airway isoform, Munc13-4, supports agonist-regulated secretion. Notably, however, not all of the mucins in Munc13-2-deficient airways were secreted, suggesting a strict Munc13-2 priming requirement for a population of secretory granules. AB/PAS+ staining of Munc13-2-deficient airways was not caused by an inflammatory, metaplastic-like response: bronchial–alveolar lavage leucocyte numbers, Muc5ac and Muc5b mRNA levels, and Clara cell ultrastructure (except for increased secretory granule numbers) were all normal. A Muc5b-specific antibody indicated the presence of this mucin in Clara cells of wildtype (WT) control mice, and increased amounts in Munc13-2-deficient mice. Munc13-2 therefore appears to prime a regulated, baseline secretory pathway, such that Clara cell Muc5b, normally secreted soon after synthesis, accumulates in the gene-deficient animals, making them stain AB/PAS+. The defective priming phenotype is widespread, as goblet cells of several mucosal tissues appear engorged and Clara cells accumulated Clara cell secretory protein (CCSP) in Munc13-2-deficient mice. Additionally, because in the human airways, MUC5AC localizes to the surface epithelium and MUC5B to submucosal glands, the finding that Muc5b is secreted by Clara cells under control conditions may indicate that it is also secreted tonically from human bronchiolar Clara cells
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