Characterization of the divalent cation activated adenosine triphosphatase from the membrane of the cardiac cell ofModiolus demissus demissus

Interactions of organic pollutants with gills of the bivalve molluscs Anodonta californiensis and Mytilus californianus: uptake and effect on membrane fluxes. II

1. The uptakes of 2,4,5-T, glyphosate, parathion, paranitrophenol, naphthalene, glycine, and inulin by gills of the bivalve molluscs Anodonta californiensis (freshwater) and Mytilus californianus (marine) show non-polar compounds are taken up to a greater extent than polar compounds except where active transport occurs. 2. The uptake of glycine by M. californianus is reduced by pollutants containing complexing functional groups but not by non-polar compounds. 3. The uptake of parathion alters the polyphosphate-inorganic phosphate balance in M. californianus. 4. The uptakes of pollutants parallel their toxicities toward rats.

The effect of acid water on the loss of divalent cations and primary amines from natural membranes

Losses of Ca2+, Mg2+ and primary amines into waters between pH = 5 and 3 from eyed Chinook salmon eggs, Oncorhynchus tshawytscha , and gills excised from the freshwater, bivalve mollusc Anodonta californiensis were measured and compared to effluxes into distilled water. Sulfuric, nitric and hydrochloric acids were used. Even at pH = 5 losses of Ca2+ and Mg2+ from both biological systems occur at short times, minutes, and can exceed those found in water of higher pH (non-acid waters). Increasing acidity increases short term primary amine loss from both systems. For both divalent cation and amino acid losses gills of A. californiensis are more sensitive to acidity than eggs of O. tshawytscha .

Effects of divalent cations on amino acid and divalent cation fluxes in gills of the bivalve mollusc, Mytilus californianus

Effects of the deletion of Ca++, Mg++, or Ca++ and Mg++ on the leakage of primary amines, Ca++, and Mg++ from gills of Mytilus californianus were studied. In the absence of Ca++ the gills leak primary amines and Ca++ for about 30 minutes, after which the primary amines are reabsorbed. In the absence of Mg++ the gills leak primary amines, with no net reabsorption for at least 90 minutes, and show rapid leakage of Mg++. In the absence of both Ca++ and Mg++ amino acid leakage is initially less than in the absence of only one of the cations. Measurements of the kinetics of leakages of Ca++ and Mg++ are consistent with the hypothesis that both ions are associated with the cell surface, but the affinity of Ca++ for the cell surface is greater than that of Mg++. In the absence of Mg++, the influx of 14C-glycine was depressed to about 1/3 that seen in controls, while deletion of Ca++ had no effect on the rate of influx. Increasing the [Mg++] stepwise between 5 x 10(-6) and 1 x 10(-1) M results in a sigmoidal increase in the rate of influx of 14C-glycine and a hyperbolic increase in the y-intercept of influx curves.