title: Biochemical studies on an acidophilic, thermophilic bacterium, Bacillus acidocaldarius: isolation of bacteria, intracellular pH, and stabilities of biopolymers.
abstract: Acidophilic, thermophilic bacteria were isolated from Japanese acidic hot springs. They were spore-forming rods, identified as Bacillus acidocaldarius. DNA extracted from these acido-thermophiles showed no abnormality in chemical structure; it was instantly denatured and gradually decomposed giving rise to apurinic acid in a hot acid environment milder than the optimal conditions for the growth of the acido-thermophiles. Glyceraldehyde-3-phosphate dehydrogenase extracted from B. acidocaldarius was not active at pH 5 or less, and was resistant to heat at neutral but not acid pH. The intracellular pH was computed to be neutral by using dimethyl-2,4-oxazolidinedione. When uncouplers or inhibitors of respiration were added to the cells suspended in hot acid solution, the estimated pH was not changed and glyceraldehyde-3-phosphate dehydrogenase in the cells was not denatured. These results suggest that the cytoplasm of B. acidocaldarius is a hot neutral environment, and that a pH gradient across the cell envelope can be maintained even when oxidative phosphorylation or respiration is inhibited.
mesh_terms: D001386:Azides / Q000494:pharmacology; D001407:Bacillus / Q000166:cytology / Q000302:isolation & purification / Q000378:metabolism*; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D004247:DNA / Q000032:analysis; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000378:metabolism; D006096:Gramicidin / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D009691:Nucleic Acid Denaturation; D013696:Temperature
chemical_list: D001386:Azides; D006096:Gramicidin; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D004247:DNA; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases