Sucrose Is a Nonaccumulated Osmoprotectant in Sinorhizobium meliloti
AUTOR(ES)
Gouffi, Kamila
FONTE
American Society for Microbiology
RESUMO
Intracellular accumulation of sucrose in response to lowered water activity seems to occur only in photosynthetic organisms. Here we demonstrate, for the first time, the potent ability of this common sugar, supplied exogenously, to reduce growth inhibition of Sinorhizobium meliloti cells in media of inhibitory osmolarity. Independently of the nature of the growth substrates and the osmotic agent, sucrose appears particularly efficient in promoting the recovery of cytoplasmic volume after plasmolysis. Surprisingly, sucrose is not accumulated by the bacteria at an osmotically efficient level. Instead, it strongly stimulates the accumulation of the main endogenous osmolytes glutamate and N-acetylglutaminylglutamine amide (NAGGN). Examining cell volume changes during the hyperosmotic treatment, we found a close correlation between the enhancement of the osmotically active solute pool and the increase in cell volume. Sucrose shares several features with ectoine, another nonaccumulated osmoprotectant for S. meliloti. Overall, osmoregulation in S. meliloti appears to be strongly divergent from that in most bacteria.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=107538Documentos Relacionados
- Disaccharides as a New Class of Nonaccumulated Osmoprotectants for Sinorhizobium meliloti
- A New Genetic Locus in Sinorhizobium meliloti Is Involved in Stachydrine Utilization
- Redundancy in Periplasmic Binding Protein-Dependent Transport Systems for Trehalose, Sucrose, and Maltose in Sinorhizobium meliloti
- Fur Is Involved in Manganese-Dependent Regulation of mntA (sitA) Expression in Sinorhizobium meliloti
- A Homolog of the CtrA Cell Cycle Regulator Is Present and Essential in Sinorhizobium meliloti