Nitrate respiration in chemoautotrophic symbionts of the bivalve Lucinoma aequizonata

Abstract

Chemoautotrophic bacteria live symbiotically in gills of Lucinoma aequizonata, an infaunal clam inhabiting an oxygen-poor environment. These intracellular symbionts respire nitrate. Nitrate is only reduced to nitrite and not further to nitrogen gas. A review of nitrate reductase in chemoautotrophic symbionts suggests that nitrate respiration may be common among these symbioses. Symbiont nitrate reductase may be an ecologically important factor permitting the survival of animal hosts in oxygen-poor environments. -from Authors