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Oxygen Consumption by Desulfovibrio Strains with and without Polyglucose
1Department of Microbiology, University of Groningen, 9751 NN Haren, The Netherlands.
Applied and Environmental Microbiology
|December 14, 2005
Summary
Polyglucose in Desulfovibrio salexigens Mast1 may protect NADH oxidase from inactivation, but oxygen-dependent growth was not observed. Different oxygen reduction systems exist across Desulfovibrio species.
Area of Science:
- Microbiology
- Biochemistry
- Enzymology
Background:
- Desulfovibrio species are known for their diverse metabolic capabilities, including respiration.
- Understanding oxygen reduction pathways is crucial for characterizing microbial energy metabolism.
- The role of intracellular storage compounds like polyglucose in microbial physiology is not fully understood.
Purpose of the Study:
- To investigate the kinetics of oxygen reduction in Desulfovibrio salexigens Mast1.
- To determine the role of polyglucose in the oxygen reduction activity of D. salexigens Mast1.
- To compare these activities with those of Desulfovibrio desulfuricans and Desulfovibrio gigas strains.
Main Methods:
- Enzyme assays were performed on cell extracts (CE) and whole cells to measure oxygen consumption rates.
- NADH oxidase, NADPH oxidase, NADH peroxidase, and NADPH peroxidase activities were quantified.
- Polyglucose accumulation and its effect on enzyme stability were assessed under various conditions.
Main Results:
- NADH oxidase was the primary system for oxygen reduction in D. salexigens Mast1.
- D. desulfuricans strains exhibited multiple oxygen reduction systems (NADH oxidase, NADPH oxidase, and a low-oxygen specific system) and also possessed peroxidase activities.
- Polyglucose in whole D. salexigens Mast1 cells appeared to slow NADH oxidase inactivation, but this effect was lost in crude cell extracts; oxygen-dependent growth was not observed.
Conclusions:
- Distinct oxygen reduction mechanisms exist among Desulfovibrio species, with D. salexigens Mast1 relying mainly on NADH oxidase.
- Polyglucose may play a protective role for NADH oxidase in whole cells, although its physiological significance for growth remains unclear.
- Further research is needed to elucidate the complete respiratory pathways and the function of polyglucose in Desulfovibrio species.
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