Parrino 2000 J Exp Biol

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Parrino V, Kraus DW, Doeller JE (2000) ATP production from the oxidation of sulfide in gill mitochondria of the ribbed mussel Geukensia demissa. J Exp Biol 203:2209-18.

» PMID: 10862733 Open Access

Parrino V, Kraus DW, Doeller JE (2000) J Exp Biol

Abstract: The ribbed mussel Geukensia demissa inhabits intertidal Spartina grass marshes characterized by sulfide-rich sediments. Sulfide poisons aerobic respiration, and G. demissa may cope in this seemingly inhospitable environment by oxidizing sulfide in gill mitochondria. Well-coupled mitochondria isolated from G. demissa gills were used to investigate sulfide oxidation and ATP synthesis. State 3 respiration, maximally stimulated by 5 micromol l(-)(1) sulfide with a P/O ratio of 0.89 and a respiratory control ratio (RCR) of 1.40, remained refractory to sulfide at higher concentrations except in the presence of salicylhydroxamic acid (SHAM), an inhibitor of alternative oxidases. Sulfide-stimulated ATP production was 3-5 times greater than that stimulated by malate and succinate, respectively, giving an ATP/sulfide ratio of 0.63. The inhibition of sulfide-stimulated respiration and ATP production by the complex III inhibitors myxothiazol and antimycin A, respectively, suggests that electrons enter the electron transport chain before complex III. Combined with in vivo evidence for electron entry at cytochrome c, these data suggest that more than one type of sulfide-oxidizing enzyme may function in G. demissa gills. The SHAM-sensitive pathway of electron flux may be a critical component of a physiological strategy to tolerate sulfide. We conclude that G. demissa exploits the energy available from its reduced environment by using sulfide as a respiratory substrate for cellular ATP production. Keywords: Geukensia demissa, Sulfide oxidation, Salicylhydroxamic acid (SHAM), Gill, Mitochondria

O2k-Network Lab: US AL Birmingham Kraus DW


Labels: MiParea: Respiration, Comparative MiP;environmental MiP 


Organism: Molluscs  Tissue;cell: Lung;gill  Preparation: Isolated mitochondria 


Coupling state: LEAK, OXPHOS  Pathway: NS  HRR: Oxygraph-2k 

Mussel