Autoradiographic analysis of amino acid uptake by the gill ofMytilus

Wright, Stephen H.; Southwell, Kathleen M.; Stephens, Grover C.

doi:10.1007/bf02464404

Cited by 13 publications

(3 citation statements)

References 27 publications

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“…The epidermis colonized by the bacteria is unciliated but has a microvillar surface. In bivalves without symbionts this lateral epidermis is an important site of uptake of dissolved organic compounds (Wright, Southwell & Stephens, 1984) and it may retain this function in the symbiont-containing species in addition to housing the symbionts and, presumably, taking up reduced sulphur compounds. Such compounds might also be taken up by the elongated foot of the mollusc during its probing of the deep layers of the sediment.…”

Section: Discussionmentioning

confidence: 99%

Gill Symbionts in Thyasirids and Other Bivalve Molluscs

1986

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Prokaryote organisms have been found in the gills of six species of Thyasiridae, collected in the north-east Atlantic region, from depths of 15 to 1250 m. The fine structure of the gill epithelia and the symbiotic Gram-negative bacteria is described. The bacteria occur extracellularly, between a thin cuticle and the apical membrane of the host cell. This differs from the intracellular position of bacterial symbionts in two lucinid species, Lucinoma borealis and Myrtea spinifera, and many other bivalves already known to harbour symbionts in their gills. Four species of Thyasiridae and Diplodonta rotundata, a member of the closely related family Ungulinidae, were found to lack gill symbionts.

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Section: Discussionmentioning

confidence: 99%

Gill Symbionts in Thyasirids and Other Bivalve Molluscs

1986

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“…Experimental approaches included employment of isolated gill tissue (Bamford & Gingles, 1974;Bamforcl & McCrea, 1975;Stewart & Bamford, 1975Wright et al, 1975;Bamford & Campbell, 1976;Stewart, 1977Stewart, , 1978Stewart, , 1981Wright & Stephens, 1977;Gomme, 1982;Wright, 1982;Wright et al, 1984) and whole animals {Anderson & Bedford, 1973;P6quinat, 1973;Crowe et al, 1977;Stewart, 1977Stewart, , 1981Manahan et al, 1982;Jergensen, 1982Jergensen, , 1983Wright, 1982;. Uptake of DOM in bivalve larvae has been studied by Fankboner & De Burgh (1978), Manahan (1983a, b), Manahan & Richardson (1983), and Manahan et al…”

Section: Introductionmentioning

confidence: 99%

Amino-acid uptake by mussels,Mytilus edulis, from natural sea water in a flow-through system

Siebers

Winkler

1984

Helgolander Meeresunters

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Natural Wadden Sea water taken from the North Sea (island of Sylt) was pumped at rates of 150 and 300 1 h -1 through a 4 1 plexiglass tube mounted on a wooden tripod on the beach.The tube was densely filled with numerous cleaned mussels, Mytilus edulis. HPLC analysis of sea water showed that total dissolved amino acids are patchily distributed, varying by 100 % within 15 man, though proportions of individual amino acids were remarkably constant. Total amino-acid concentrations were 1528 _. 669 nM (N ~ 3) in October 1983 and 1198 _ 597 nM (N = 7) in July 1984. Samples taken at the entrance and the outlet of the experimental mussel bed revealed that the mussels had taken up 29 to 66 % of the amino acids dissolved in sea water. Uptake was observed for all amino acids detected in the chromatograms. 78 % of uptake resulted from the 5 most concentrated amino acids: serine, alanine, glycine/threonine, ornithine, aspartic acid. The nutritional profit obtained from uptake of dissolved amino acids amounted to 12 % (N ~ 5, range 5-23 %, flow rate 150 1 h -1) and to 24 % (N = 3, range 13-38 %, flow rate 3001 h -1) of metabolic rate. The present data suggest that amino-acid concentration predominantly determines the magnitude of the nutritional profit obtained from uptake, and to a smaller extent the flow rate. These findings are in contrast to results of previous studies on Asterias rubens, interacting in small-volume closed systems with the natural bacterial sea water flora (Siebers, 1982). In these experiments, bacteria, due to rapid uptake, outcompeted the sea stars in absorption of dissolved amino acids. The present results suggest that bivalve mussels, can, due to their large gill surface areas and the great amounts of water pumped through their mantle cavity, successfully compete with bacteria in uptake of dissolved organic matter. Mussels, therefore, suggestedly play an important role in cycling dissolved organic matter.

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“…l) l0 min prior to beginning the experiments. The subsequent reduction in unstirred layers between adjacent gill filaments reestablishes a pattern of perfusion of gill surfaces that mimics the in vivo situation, thereby stimulating amino-acid uptake [34,40]. Separate experiments have shown that 5-HT does not have a direct effect on transport in the gill [34].…”

Section: Transport Measurementsmentioning

confidence: 93%

Alanine and taurine transport by the gill epithelium of a marine bivalve: Effect of sodium on influx

Wright

1987

J. Membrain Biol.

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Summary. Marine mussels can accumulate amino acids from seawater into the epithelial cells of the gill against chemical gradients in excess of 5 x 106 to 1. Uptake of both alanine and taurine into gill tissue isolated from Mytilus californianus was found to be dependent upon Na § in the external solution. Uptake of these amino acids was described by Michaelis-Menten kinetics, and a reduction in external [Na § (from 425 to 213 mM) increased the apparent Michaelis constants (alanine, from 8 to 17/xM; taurine, from 4 to 39 /ZM) without a significant influence on the Jmax'S of these processes. Five mM harmaline, an inhibitor of Na-cotransport processes in many systems, reduced both alanine and taurine uptake by more than 95%; this inhibition appeared to be competitive in nature, with an apparent Ki of 43 /.LM for the interaction with alanine uptake. Increasing the external [Na § from 0 to 510 mM produced a sigmoid activation of alanine and taurine uptake with gNa'S of approximately 325 mM. The apparent Hill coefficients for this activation were 7.3 and 7.4 for alanine and taurine, respectively. These data are consistent with uptake mechanisms which require comparatively high concentrations of Na + to activate transport, and which couple several Na § ions to the transport of each amino acid. These characteristics, in conjunction with the previously demonstrated low passive permeability of the apical membrane to amino acids, result in systems capable of i) accumulating amino acids from seawater to help meet the nutritional needs of this animal, and ii) maintaining the high intracellular amino-acid concentrations associated with volume regulation in the gill. Key Wordsepithelia 9 integument 9 coupled transport 9 amino-acid transport 9 taurine -alanine -marine bivalve -Mytilus californianus

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Autoradiographic analysis of amino acid uptake by the gill ofMytilus

Cited by 13 publications

References 27 publications

Gill Symbionts in Thyasirids and Other Bivalve Molluscs

Gill Symbionts in Thyasirids and Other Bivalve Molluscs

Amino-acid uptake by mussels,Mytilus edulis, from natural sea water in a flow-through system

Alanine and taurine transport by the gill epithelium of a marine bivalve: Effect of sodium on influx

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