Enhanced phosphate uptake and polyphosphate accumulation in Burkholderia cepacia grown under low pH conditions.
Of bacterial cells in a sample of activated sludge, 34% contained detectable intracellular polyphosphate inclusions following Neisser staining, when grown on glucose/mineral salts medium at pH 5.5; at pH 7.5 only 7% of cells visibly accumulated polyphosphate. In a sludge isolate of Burkholderia cepacia chosen for further study, maximal removal of phosphate and accumulation of polyphosphate occurred at pH 5.5; levels were up to 220% and 330% higher, respectively, than in cells grown at pH 7.5. During the early stationary phase of growth at pH 5.5 a maximum level of intracellular polyphosphate that comprised 13.6% of cellular dry weight was reached. Polyphosphate kinase activity was detected in actively growing cells only when cultured at pH 5.5. The phenomenon of acid-stimulated phosphate uptake and polyphosphate accumulation in this environmental bacterial population parallels observations previously made by us in the yeast Candida humicola and may thus represent a widespread microbial response to low external pH values.
School of Biology and Biochemistry and QUESTOR Centre, The Queen's University of Belfast, Northern Ireland.
A
A
Mullan
J P
JP
Quinn
J W
JW
McGrath
D016956:Burkholderia cepacia / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism* / Q000648:ultrastructure; D003470:Culture Media; D004777:Environment; D006863:Hydrogen-Ion Concentration; D010755:Organophosphates / Q000378:metabolism*; D017856:Phosphotransferases (Phosphate Group Acceptor) / Q000378:metabolism; D011122:Polyphosphates / Q000378:metabolism*; D012722:Sewage / Q000382:microbiology; D013997:Time Factors
D003470:Culture Media; D010755:Organophosphates; D011122:Polyphosphates; D012722:Sewage; D017856:Phosphotransferases (Phosphate Group Acceptor); C022424:polyphosphate kinase