Physiological and morphological responses of the soil bacterium Rhodococcus opacus strain PD630 to water stress
| Autor: | Silvia R. Peressutti, Ursula Malkus, Ulrike Keller, Ana C. Cesari, Frank Mayer, Christiane Rasch, Thomas Maskow, Héctor M. Alvarez, Rudolf Reichelt, Alexander Steinbüchel, Ana L. Zamit, Roxana A. Silva |
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| Rok vydání: | 2009 |
| Předmět: |
Osmotic shock
Ectoine Applied Microbiology and Biotechnology Microbiology Gluconates 03 medical and health sciences Rhodococcus opacus chemistry.chemical_compound Cell Wall Osmotic Pressure Stress Physiological Alkanes medicine Osmotic pressure Rhodococcus Dehydration Soil Microbiology Triglycerides 030304 developmental biology 0303 health sciences Microbial Viability Ecology biology 030306 microbiology Polysaccharides Bacterial Amino Acids Diamino Trehalose biology.organism_classification medicine.disease 6. Clean water Biochemistry chemistry Osmolyte Energy Metabolism |
| Zdroj: | FEMS microbiology ecology. 50(2) |
| ISSN: | 1574-6941 |
| Popis: | Rhodococcus opacus PD630 was investigated for physiological and morphological changes under water stress challenge. Gluconate- and hexadecane-grown cells were extremely resistant to these conditions, and survival accounted for up to 300 and 400 days; respectively, when they were subjected to slow air-drying. Results of this study suggest that strain PD630 has specific mechanisms to withstand water stress. Water-stressed cells were sensitive to the application of ethanol, high temperatures and oxidative stress, whereas they exhibited cross-protection solely against osmotic stress during the first hours of application. Results indicate that the resistance programme for water stress in R. opacus PD630 includes the following physiological and morphological changes, among others: (1) energetic adjustments with drastic reduction of the metabolic activity ( approximately 39% decrease during the first 24 h and about 90% after 190 days under dehydration), (2) endogenous metabolism using intracellular triacylglycerols for generating energy and precursors, (3) biosynthesis of different osmolytes such as trehalose, ectoine and hydroxyectoine, which may achieve a water balance through osmotic adjustment and may explain the overlap between water and osmotic stress, (4) adjustments of the cell-wall through the turnover of mycolic acid species, as preliminary experiments revealed no evident changes in the thickness of the cell envelope, (5) formation of short fragmenting-cells as probable resistance forms, (6) production of an extracellular slime covering the surface of colonies, which probably regulates internal and external changes in water potential, and (7) formation of compact masses of cells. This contributes to understanding the water stress resistance processes in the soil bacterium R. opacus PD630. |
| Databáze: | OpenAIRE |
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