Shifts in membrane fatty acid profiles associated with acid adaptation of Streptococcus mutans

Cells of Streptococcus,mutans UA159 physiologically adapted to acidificatio n during growth at pH 5 in glucose-limited chemostat cultures were enriched in mono-unsaturated and longer chain fatty acids compared with unadapted c ells grown under the same conditions but at pH 7. Ratios of unsaturated to saturated fatty acids in the cells were, respectively, 1.2 and 0.3. Cyclopr opane fatty acids were not detected. Streptococcus sobrinus 6715, which is known to have minimal acid-adaptive capacity, showed only minimal change in membrane fatty acids. (C) 2000 Federation of European Microbiological Soci eties. Published by Elsevier Science B.V. All rights reserved.