Activity of H(+)-ATPase in ruminal bacteria with special reference to acid tolerance.
Batch culture experiments showed that permeabilized cells and membranes of Ruminococcus albus and Fibrobacter succinogenes, acid-intolerant celluloytic bacteria, have only one-fourth to one-fifth as much H(+)-ATPase as Megasphaera elsdenii and Streptococcus bovis, which are relatively acid tolerant. Even in the cells grown in continuous culture at pH 7.0, the acid-intolerant bacteria contained less than half as much H(+)-ATPase as the acid-tolerant bacteria. The amounts of H(+)-ATPase in the acid-tolerant bacteria were increased by more than twofold when the cells were grown at the lowest pH permitting growth, whereas little increase was observed in the case of the acid-intolerant bacteria. These results indicate that the acid-intolerant bacteria not only contain smaller amounts of H(+)-ATPase at neutral pH but also have a lower capacity to enhance the level of H(+)-ATPase in response to low pH than the acid-tolerant bacteria. In addition, the H(+)-ATPases of the acid-intolerant bacteria were more sensitive to low pH than those of the acid-tolerant bacteria, although the optimal pHs were similar.
Miwa
T
T
Department of Agriculture, Meiji University, Kawasaki, Japan.
Esaki
H
H
Umemori
J
J
Hino
T
T
D000818:Animals; D001419:Bacteria / Q000201:enzymology*; D001421:Bacteria, Anaerobic / Q000201:enzymology; D002482:Cellulose / Q000378:metabolism; D006089:Gram-Negative Anaerobic Bacteria / Q000201:enzymology; D006095:Gram-Positive Cocci / Q000201:enzymology; D006863:Hydrogen-Ion Concentration; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D012417:Rumen / Q000382:microbiology*; D016985:Streptococcus bovis / Q000201:enzymology; D045854:Veillonellaceae / Q000201:enzymology
D002482:Cellulose; D006180:Proton-Translocating ATPases