Trapezia

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Yang Meng - One of the best experts on this subject based on the ideXlab platform.

Liu Guang-chun - One of the best experts on this subject based on the ideXlab platform.

William A. Maher - One of the best experts on this subject based on the ideXlab platform.

  • mortality condition index and cellular responses of anadara Trapezia to combined salinity and temperature stress
    2017
    Co-Authors: Anne M Taylor, William A. Maher, Rodney P Ubrihien
    Abstract:

    Abstract As a consequence of accelerated global warming, estuarine and marine bay temperature and salinity regimes will change, influencing the survival, reproduction and development of marine organisms, especially bivalve species. In order to understand their response to temperature and salinity variations the bivalve mollusc Anadara Trapezia , was exposed for 56 days to twelve combinations of temperature and salinity (10 °C–20 °C–30 °C/15 ppt–20 ppt–25 ppt–30 ppt) in laboratory controlled conditions. Mortality was assessed daily over the course of the exposure. After 56 days, a suite of responses were measured in surviving organisms, including biomarkers at the molecular and cellular level; total antioxidant capacity, lipid peroxidation and lysosomal membrane destabilisation and at the whole organism level as condition index. Greater mortality occurred at temperature extremes (10 °C and 30 °C) and the lowest salinity treatment (15 ppt). Total antioxidant capacity was not significantly different but lower TOAC occurred at temperature extremes. Lipid peroxidation was also significantly higher at temperature extremes while salinity had no effect. Lysosomal membrane destabilisation was influenced by temperature and salinity with lysosomal membrane destabilisation increasing at temperature extremes and as salinity decreased. As TOAC decreased, the trends were for lipid peroxidation and lysosomal membrane destabilisation to increase and condition index and survival to decrease. The results demonstrate that A . Trapezia can tolerate changes in either salinity or temperature but deleterious biochemical changes, high mortality and reduced condition occur when these vary in unison at temperature extremes and low salinity.

  • exposure dose response of anadara Trapezia to metal contaminated estuarine sediments 3 selenium spiked sediments
    2012
    Co-Authors: Anne M Taylor, William A. Maher
    Abstract:

    Abstract Selenium enters near shore marine environments from the activities of coal-fired power stations. Although selenium is an essential element, at elevated concentrations it can cause genotoxic damage. The relationship between selenium exposure dose and response was investigated in Anadara Trapezia exposed to selenium spiked sediment (5 μg/g and 20 μg/g dry mass) for 56 days. A. Trapezia reached an equilibrium selenium tissue concentration (2 μg/g and 10 μg/g respectively) by day 42. Gills had significantly more selenium than the hepatopancreas and haemolymph. Between 12 and 21% of accumulated selenium in the gill and hepatopancreas was detoxified and in the metal rich granule. Most of the biologically active selenium in both tissues was in the mitochondrial fraction. Glutathione peroxidase activity and mean total glutathione concentrations for selenium exposed organisms were not significantly different to controls. The ratio of reduced to oxidised glutathione and the total antioxidant capacity were significantly reduced in selenium exposed organisms compared to control organisms. Increased selenium exposure resulted in significant increases in lipid peroxidation, lysosomal destabilisation and an increased frequency of micronuclei. A significant exposure–dose–response relationship for A. Trapezia exposed to selenium enriched sediments indicates that elevated sediment selenium concentrations can increased biologically active selenium burdens and cause impairment of cellular processes and cell integrity.

  • exposure dose response of anadara Trapezia to metal contaminated estuarine sediments 1 cadmium spiked sediments
    2012
    Co-Authors: Anne M Taylor, William A. Maher
    Abstract:

    The composition of near shore marine environments is increasingly being altered by contaminants from human activities. The ability of lead, which has no known biological function, to mimic biologically essential metals makes it one of the most toxic to marine biota. The relationship between lead exposure, dose and response was investigated in Anadara Trapezia exposed for 56 days to lead spiked sediment (100 and 300 μg/g dry mass). Lead tissue concentrations of the 300 μg/g exposed A. Trapezia doubled in the last 2 weeks of exposure with final lead tissue concentrations of exposed organisms of 1 and 12 μg/g, respectively. Tissue lead accumulation of exposed organisms followed the pattern haemolymph>gill>hepatopancreas during much of the 56 day exposure. Between 30 and 69% of accumulated lead in the gill and hepatopancreas was detoxified and fairly evenly distributed between the metal rich granule and the metallothionein like protein fractions. Approximately half of the biologically active lead in both tissues was in the mitochondrial fraction which showed increased cytochrome c oxidase activity in lead exposed organisms. There was a reduction in GPx activity, an associated increase in total glutathione concentrations and reduced GSH:GSSG ratios due to a build up of oxidised glutathione. These changes in the glutathione pathway were reflected in the total antioxidant capacity of lead exposed A. Trapezia which were significantly reduced compared to control organisms. Increased lead exposure significantly increased lipid peroxidation, lysosomal destabilisation and frequency of micronuclei. A significant exposure-dose-response relationship for A. Trapezia exposed to lead enriched sediments indicates that elevated sediment lead concentrations have the potential to increase biologically active lead burdens and impair the antioxidant reduction capacity leading to a series of associated effects from lipid peroxidation to cellular perturbation and genotoxic damage.

  • the accumulation of zn se cd and pb and physiological condition of anadara Trapezia transplanted to a contamination gradient in lake macquarie new south wales australia
    2007
    Co-Authors: A Burt, William A. Maher, Anthony C Roach, Frank Krikowa, P Honkoop, B Bayne
    Abstract:

    The benthic bivalve, Anadara Trapezia, was collected from a 'clean' reference site and transplanted along a suspected trace metal contamination gradient in Lake Macquarie, NSW. At monthly intervals, Zn, Se, Cd and Pb concentrations were measured in the surficial sediments and whole tissues of the cockle as well as their physiological condition (Scope for Growth). Zinc, Cd and Pb concentrations in sediments decreased together, southward, with the highest concentrations in the Cockle Bay area, suggesting that this is the main source of contamination. Zinc, Cd and Pb concentrations were near or above [ANZECC/ARMCANZ, 2000. National water quality management strategy paper 4. Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Australian and New Zealand Conservation Council and Agriculture and Resource Management Council of Australia and New Zealand. pp. 3.5.-1-3.5-10] sediment quality guidelines at Cockle Creek, Warners Bay and Koorooa Bay. Significant differences in trace metal concentrations could not be attributed to grain size or Fe concentration differences. Se concentrations were highest in fine grain Fe rich sediments of Whiteheads Lagoon, and likely to be associated with power generation operations. Trace metal concentrations did not vary significantly over time. Zinc, Cd and Pb concentrations in the tissues of A. Trapezia followed a similar pattern to that of sediments. Zinc and Pb concentrations in cockles and sediments were highly correlated, indicating significant exposure-dose relationships. Selenium concentrations in the tissues of A. Trapezia were higher after transplantation to the lake, however, Se concentrations were similar in all transplanted cockles, indicating that Se in contaminated sediments is not the major source of Se to organisms. There was a decline in the physiological condition of A. Trapezia transplanted to Lake Macquarie after a 90-day-period with marked differences in clearance rates and respiration rates at some locations and absorption efficiencies at all locations. The mean Scope for Growth value at the most contaminated location, Cockle Bay, was markedly lower than at other locations. A significant Zn exposure-dose response relationship indicates that Zn bioaccumulation is occurring in response to sediment contamination. A significant Cd exposure-response relationship indicates that Cd may be influencing the health of cockles. Significant Pb exposure-dose, exposure-response and dose-response relationships indicate that Pb probably is affecting the health of cockles in Lake Macquarie. Therefore, Zn, Cd and Pb concentrations in sediments are likely to be affecting the health of cockles in Lake Macquarie.

  • Selenium accumulation in the cockle Anadara Trapezia.
    2004
    Co-Authors: Dianne F. Jolley, William A. Maher, Jennelle M. Kyd
    Abstract:

    An extensive study on Se accumulation in a population of Anadara Trapezia from a marine lake is reported. The effects of organism mass, gender, reproductive cycle, and season on Se accumulation and tissue distribution were investigated. Analyses showed that gender and reproductive cycle had no significant effect on Se accumulation. A. Trapezia showed a strong positive correlation between Se burden and tissue mass. Constant Se concentrations were observed within individual populations but varied spatially with sediment Se concentrations. Se concentrations in tissues decreased from gills > gonad/intestine > mantle > muscle > foot, which remained constant over 12 months, however, significantly lower concentrations were observed in the summer compared to winter. A. Trapezia is a good biomonitor for Se, as gender and size do not effect concentration, however, season of collection must be reported if changes in Se bioavailability are to be identified in short term studies, or during intersite comparisons.

Li Houhun - One of the best experts on this subject based on the ideXlab platform.

Andrew C Barnes - One of the best experts on this subject based on the ideXlab platform.

  • effect of a hemiuroid trematode on the hemocyte immune parameters of the cockle anadara Trapezia
    2013
    Co-Authors: Cecile Dang, Thomas H Cribb, Geoffrey W Osborne, Minami Kawasaki, Annesophie Bedin, Andrew C Barnes
    Abstract:

    When a trematode parasite penetrates a potential molluscan host, it has to circumvent the host's internal defense system. In molluscs, the primary effector cells of this system are the hemocytes which orchestrate many of the cellular and humoral immune functions. Survival of the parasite can occur only in the absence of a successful immune response, and continued development only if the host is physiologically suitable. This study investigated hemocytic response against asexual stages of a hemiuroid trematode by its host, the marine bivalve Anadara Trapezia. Hemocyte characteristic (type, morphology) and function (mortality, phagocytosis and oxidative activity) were analyzed by flow cytometry in parasitized and non-parasitized cockles. A. Trapezia possesses two types of hemocytes: amebocytes and erythrocytes. Analysis of histological section showed that there was no host hemocytic response around hemiuroid sporocysts. The infection induced a significant increase of the total circulating hemocytes with a higher proportion of erythrocytes relative to amebocytes, coupled with a lower phagocytosis rate and a statistically non-significant decrease of the intracellular oxidative activity. No significant differences were observed in hemocyte size and complexity, mortality, or phagocytic capacity. Our results indicate that in A. Trapezia, hemiuroids modulate the immune response by increasing the number of circulating hemocytes and decreasing phagocytosis.

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