Ionic and osmotic influence on prostaglandin release from the gill tissue of a marine bivalve, Modiolus demissus

1980 ◽  
Vol 84 (1) ◽  
pp. 169-185
Author(s):  
W. Freas ◽  
S. Grollman
Keyword(s):  
Arachidonic Acid ◽  
Sea Water ◽  
Gill Tissue ◽  
Adductor Muscle ◽  
Prostaglandin Synthesis ◽  
Marine Bivalve ◽  
Visceral Mass ◽  
Prostaglandin Release ◽  
Hyposmotic Stress ◽  
Wet Weight

1. Prostaglandin E2 (PGE2) was identified in Modiolus demissus gill tissue on the basis of solvent extraction, thin layer and column chromatography, bioassay, and radioimmunoassay. The presence of PGE2 was detected in both tissue and sea water incubate surrounding the tissue. 2. Both hyposmotic stress and magnesium-free sea water significantly increased release of prostaglandins into sea water. Hyposmotic stress also significantly increased prostaglandin synthesis. 3. Examination of tissues revealed that homogenates of the mantle and lower visceral mass contained significantly fewer nanograms immunoreactive prostaglandins per gram wet weight than homogenates of the gill, posterior adductor muscle, upper visceral mass, or siphon tissue. 4. Prostaglandin release could be increased by addition of arachidonic acid, and inhibited by addition of acetylsalicylic acid or indomethacin.

The contribution of nitrate respiration to the energy budget of the symbiont-containing clam Lucinoma aequizonata: a calorimetric study

1996 ◽  
Vol 199 (2) ◽  
pp. 427-433
Author(s):  
U Hentschel ◽  
S Hand ◽  
H Felbeck
Keyword(s):  
Heat Production ◽  
Sea Water ◽  
Anaerobic Respiration ◽  
Gill Tissue ◽  
Nitrate Respiration ◽  
Heat Output ◽  
Marine Bivalve ◽  
Calorimetric Study ◽  
Perfusion Medium ◽  
Terminal Electron Acceptor

Heat production and nitrate respiration rates were measured simultaneously in the gill tissue of Lucinoma aequizonata. This marine bivalve contains chemoautotrophic, intracellular, bacterial symbionts in its gill tissue. The symbionts show constitutive anaerobic respiration, using nitrate instead of oxygen as a terminal electron acceptor. An immediate increase in heat production was observed after the addition of nitrate to the perfusion medium of the calorimeter and this was accompanied by the appearance of nitrite in the effluent sea water. The nitrate-stimulated heat output was similar under aerobic and anaerobic conditions, which is consistent with the constitutive nature of nitrate respiration. The amount of heat released was dependent on the concentration of nitrate in the perfusion medium. At nitrate concentrations between 0.5 and 5 mmol l-1, the total heat production was increased over twofold relative to unstimulated baseline values. A mean (±s.e.m.) experimental enthalpy of -130±22.6 kJ mol-1 nitrite (N=13) was measured for this concentration range.

The effects of exposure to ammonia on ammonia and taurine pools of the symbiotic clam

1997 ◽  
Vol 200 (21) ◽  
pp. 2797-2805 ◽  
Author(s):  
R Lee ◽  
J Childress ◽  
N Desaulniers
Keyword(s):  
Amino Acid ◽  
Sea Water ◽  
Gill Tissue ◽  
Ammonia Concentration ◽  
Major Product ◽  
Single Amino Acid ◽  
Ammonia Assimilation ◽  
Visceral Mass ◽  
Taurine Level ◽  
Chemoautotrophic Bacteria

The nutrition of the gutless clam Solemyareidi is supported by the activity of intracellular chemoautotrophic bacteria housed in its gill filaments. Ammonia (the sum of NH3 and NH4+) is utilized as a nitrogen source by the association and is abundant in the clam's environment. In the present study, clams were exposed to 0.01­1.3mmoll-1 ammonia for 22­23h in the presence of thiosulfate as a sulfur substrate. Ammonia exposure increased the ammonia concentration in the tissue pools of the gill, foot and visceral mass from 0.5 to 2µmolg-1wetmass, without added ammonia, to as much as 12µmolg-1wetmass in the presence of 0.7 and 1.3mmoll-1 external ammonia. Gill tissue ammonia concentrations were consistently higher than those in the foot and visceral mass. The elevation of tissue ammonia concentration compared with the medium may be due in part to an ammonia trapping mechanism resulting from a lower intracellular pH compared with sea water and greater permeability to NH3 compared with NH4+. Rates of ammonia incorporation into organic matter (assimilation) were determined using 15N as a tracer. 15N-labeled ammonia assimilation was higher in gill than in foot and increased as a function of 15N-labeled ammonia concentration in the medium. The size of the free amino acid (FAA) pool in the gill also increased as a function of ammonia concentration in the medium. This entire increase was accounted for by a single amino acid, taurine, which was the predominant FAA in both gill and foot tissue. Aspartate, glutamate, arginine and alanine were also abundant but their levels were not influenced by external ammonia concentration. Ammonia assimilation appeared to occur at rates sufficient to account for the observed increase in taurine level. These findings suggest that taurine is a major product of ammonia assimilation.

Cadmium Uptake by Marine Organisms

1972 ◽  
Vol 29 (9) ◽  
pp. 1367-1369 ◽  
Author(s):  
R. Eisler ◽  
G. E. Zaroogian ◽  
R. J. Hennekey
Keyword(s):  
Crassostrea Virginica ◽  
Fundulus Heteroclitus ◽  
Sea Water ◽  
Homarus Americanus ◽  
Adductor Muscle ◽  
Marine Organisms ◽  
Cadmium Uptake ◽  
Wet Weight

Adults of mummichog, Fundulus heteroclitus, scallop Aquipecten irradians, oyster Crassostrea virginica, and subadult lobsters Homarus americanus were immersed for 21 days in flowing sea water containing 10 μg/liter of cadmium as[Formula: see text]. Cadmium residues in whole animals and selected tissues were consistently higher in exposed organisms than controls; edible portions of treated lobster (muscle), scallop (adductor muscle), and oyster (whole animal) contained more cadmium per unit wet weight than controls by 25%, 19%, and 352%, respectively.

scholarly journals Intracellular Na+ and the control of amino acid fluxes in the integumental epithelium of a marine bivalve

1989 ◽  
Vol 142 (1) ◽  
pp. 293-310
Author(s):  
S. H. Wright ◽  
D. A. Moon ◽  
A. L. Silva
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Sea Water ◽  
Gill Tissue ◽  
Transport Systems ◽  
Amino Acid Transporters ◽  
Marine Bivalve ◽  
Chemical Gradients ◽  
Influx Pathways ◽  
Taurine Efflux

The accumulation of amino acids from sea water into the integumental epithelium of the bivalve gill can occur against chemical gradients in excess of 10(6) to 1. The energy to drive this transport has been proposed to come from the inwardly directed Na+ electrochemical gradient. The present study examined the influence of intracellular and extracellular [Na+] on influx and efflux of amino acids in gill tissue from the mussel, Mytilus californianus. Influx of alanine was inhibited by more than 90% when external [Na+] was reduced from 425 to 2 mmol l-1, and by 85% when intracellular [Na+] was increased from approximately 11 to approximately 100 mmol l-1 (by means of a 30-min exposure to the ionophore, nigericin). Efflux of taurine and alanine from gill tissue into normal-Na+ sea water was very low (less than 5% of the Jmax of the carrier-mediated influx pathways). Reducing the external Na+ from 425 to 2 mmol l-1 increased taurine efflux by only 20%. Raising cell [Na+] to approximately 100 mmol l-1 increased taurine efflux 2.7-fold; further increases in cell [Na+] increased taurine efflux another 7.5-fold. These data, in conjunction with results from earlier studies, suggest that activation of integumental amino acid transporters requires an interaction of multiple sodium ions with binding sites of low affinity for this ion. This set of characteristics results in transport systems that are well-adapted for the net accumulation of amino acids from sea water.

scholarly journals Aedes Aegypti: Energetics of Osmoregulation

1982 ◽  
Vol 101 (1) ◽  
pp. 135-141 ◽  
Author(s):  
H.A. EDWARDS
Keyword(s):  
Oxygen Consumption ◽  
Energy Cost ◽  
Sea Water ◽  
External Medium ◽  
Minimum Energy ◽  
Body Volume ◽  
Wet Weight ◽  
Minimum Energy Cost ◽  
Anal Papillae ◽  
Theoretical Minimum

1. Oxygen consumption of A. aegypti larvae, about 210 mul l g−1 tissue wet weight h−1, does not change when the salinity of the environment is changed. The number of mitochondria in the anal papillae, a salt-absorbing epithelium, increases as the external medium is diluted. There is no difference in oxygen consumption between isolated anal papillae in 0, 2 and 20% sea water. The papillae represent about 5% of body volume and their oxygen consumption is about 2% of the animal's total. The theoretical minimum energy cost of osmoregulation is four orders of magnitude smaller than the measured figure for the anal papillae alone. Osmoregulatory phenomena which would explain the recorded observations are discussed.

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