INVESTIGADORES
ALVAREZ Hector Manuel
congresos y reuniones científicas
Título:
Rhodococcus opacus PD630 adapts its physiological state to environmental conditions.
Autor/es:
TOLEDO DN; SILVA RA,; ALVAREZ, H. M.
Lugar:
Viena, Austria
Reunión:
Simposio; 11th International Symposium on Microbial Ecology (ISME-11); 2006
Resumen:
Background: In East Patagonia (Argentina), some sites are contaminated with hydrocarbons as result of intensive activities of the oil industry. In the context of an agreement with Oil M&S company, we are evaluating the use of Rhodococcus bacteria for bioremediation processes. In addition to their biodegradation capabilities, we are investigating other aspects of their physiology that control their growth and activity in soil. Methods: Survival of cells under different stresses was investigated by cell counts (CFU). Metabolic activity in cells was investigated using tetrazolium chloride as colorimetric indicator of respiratory activity. Variation in triacylglycerol content in cells was investigated by lipid extraction and thin-layer chromatography. Results: In a culture containing unlimited nutrients, growth- and metabolic activity rates were higher than during cultivation of cells under stress conditions. Under N-starvation conditions in the presence of a carbon source, metabolic rate of cells decreased, resulting in an increase in triacylglycerol deposition. Metabolic activity significantly dropped during C-starvation, triacylglycerols were slowly utilized, whereas cell counts remained constant. When b-oxidation pathway was inhibited by the addition of acrylic acid under C-starvation, storage lipids were not mobilized, metabolic activity was suppressed and cell counts decreased. C-starved cells incubated at low temperatures (4° C) were able to respond to the addition of a carbon source, increasing their metabolic activity. Conclusions: R. opacus remained active in a wide range of environmental conditions. Cells were able to adopt a low metabolic state under stress conditions, which allows a slow utilization of stored lipids and reduces its energy-demanding processes.