TY - JOUR
T1 - Uptake of succinate and malate in cultured cells and bacteroids of two slow-growing species of Rhizobium
AU - San Francisco, M. J.D.
AU - Jacobson, G. R.
PY - 1985
Y1 - 1985
N2 - The uptake of succinate and malate had been compared in cultured cells and bacteroids of two species of slow-growing Rhizobium: R. japonicum (USDA I-110) and cowpea Rhizobium (USDA 3278). Cultured cells of both organisms actively accumulated both compounds, and uptake was abolished by KCN and 2,4-DNP, but not by arsenate. Kinetic studies using cultured cells showed that succinate competitively inhibited malate uptake, and vice versa, implying a common step in the uptake of these dicarboxylic acids. Uptake of both of these compounds was inhibited by osmotic shock and N-ethylmaleimide in cultured cells of both species. Purified bacteroids accumulated succinate in a process that was sensitive to 2,4-DNP and KCN, but at a rate significantly slower than for cultured cells. No detectable malate uptake was observed in purified symbiotic cells. Furthermore, succinate uptake was insensitive to osmotic shock in bacteroids of both strains. These results show that although bacteroids of both strains are competent in succinate uptake, significant differences exist in the expression and/or stability of dicarboxylate uptake systems between free-living and symbiotic cells.
AB - The uptake of succinate and malate had been compared in cultured cells and bacteroids of two species of slow-growing Rhizobium: R. japonicum (USDA I-110) and cowpea Rhizobium (USDA 3278). Cultured cells of both organisms actively accumulated both compounds, and uptake was abolished by KCN and 2,4-DNP, but not by arsenate. Kinetic studies using cultured cells showed that succinate competitively inhibited malate uptake, and vice versa, implying a common step in the uptake of these dicarboxylic acids. Uptake of both of these compounds was inhibited by osmotic shock and N-ethylmaleimide in cultured cells of both species. Purified bacteroids accumulated succinate in a process that was sensitive to 2,4-DNP and KCN, but at a rate significantly slower than for cultured cells. No detectable malate uptake was observed in purified symbiotic cells. Furthermore, succinate uptake was insensitive to osmotic shock in bacteroids of both strains. These results show that although bacteroids of both strains are competent in succinate uptake, significant differences exist in the expression and/or stability of dicarboxylate uptake systems between free-living and symbiotic cells.
UR - http://www.scopus.com/inward/record.url?scp=0021813484&partnerID=8YFLogxK
U2 - 10.1099/00221287-131-4-765
DO - 10.1099/00221287-131-4-765
M3 - Article
AN - SCOPUS:0021813484
VL - 131
SP - 765
EP - 773
JO - Journal of General Microbiology
JF - Journal of General Microbiology
SN - 0022-1287
IS - 4
ER -