The contribution of nitrate respiration to the energy budget of the symbiont-containing clam <i>Lucinoma aequizonata</i>: A calorimetric study

Citation:
Hentschel, U, Hand SC, Felbeck H.  1996.  The contribution of nitrate respiration to the energy budget of the symbiont-containing clam Lucinoma aequizonata: A calorimetric study. Journal of Experimental Biology. 199:427-433.

Date Published:

Feb

Keywords:

bacteria, calorimetry, chemoautotrophic symbionts, chemoautotrophy, clam, floridana, growth, heat dissipation, Lucinoma aequizonata, marine-invertebrates, metabolism, nitrate respiration, riftia-pachyptila, solemya-reidi, sulfide oxidation, symbiosis

Abstract:

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 mmoll(-1), the total heat production was increased over twofold relative to baseline values. A mean (+/-S.E.M.) enthalpy of -130+/-22.6 kJ mol(-1) nitrite (N=13) was measured for this concentration range.

Notes:

n/a

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