Bioenergetic Properties of Alkaline-tolerant and Alkalophilic Strains of Bacillus firmus
Guffanti, Arthur A. and Blanco, Robert and Benenson, Robert A. and Krulwich, Terry A.,, 119, 79-86 (1980),
doi = https://doi.org/10.1099/00221287-119-1-79,
publicationName = Microbiology Society,
issn = 1350-0872,
abstract= The protonmotive force, Na+/H+ antiport activity and a-aminoisobutyric acid transport were studied in alkaline-tolerant Bacillus firmus ATCC 14575 and in a newly isolated alkalophilic strain of the same species. The alkalophilic strain, which grew over a pH range from 8·0 to 10·5, maintained a cytoplasmic pH of 9·5 or below even at an external pH of 110. Evidence was obtained for an electrogenic Na+/H+ antiporter which could play a role in acidification of the cytoplasm as well as in generation of the transmembrane electrical potential. A non-alkalophilic strain, isolated after mutagenesis of the new alkalophile, lacked the Na+/H+ antiporter. The alkaline-tolerant strain of B. firmus, which grew at pH values between 6·5 and 8·5, did not maintain an acidified cytoplasm as the pH was raised above 8·0. A less active, apparently electroneutral, Na+/H+ exchange was found in this strain. Both the alkaline-tolerant and alkalophilic strains exhibited Na+-dependent transport of α-aminoisobutyric acid.,
language=,
type=