Adaptation of the Membrane Fatty Acid Composition by Growth in the Presence of n-Alkanols Influences Glycosyltransferase Expression in Streptococcus salivarius

Abstract

Growth of Streptococcus salivarius ATCC 25975 in the presence of n-alkanols in the series methanol to decan-1-ol led to a decrease in the unsaturated to saturated fatty acid ratio. Each member of the set of n-alkanols which was examined over a range of concentrations possessed a point at which extracellular glucosyltransferase (GTF) production was minimal; increasing the concentration of the n-alkanol past this point stimulated GTF production. This effect was greatest with hexan-1-ol although it was observed to a lesser extent with pentan-1-ol and heptan-1-ol. Reduced cell-associated fructosyltransferase activity was observed with increasing concentrations of each n-alkanol. Growth in the presence of 25 mM-propan-1-ol gave rise to a fatty acid profile in which 55% of the fatty acids were of an odd chain length. S. salivarius ATCC 25975 was shown to be able to utilize ethanol in a similar manner to propan-1-ol by growing it in the presence of 400 mM-[14C]ethanol. Analysis of the membrane lipids at the stationary phase of growth indicated that 17.6% of the carbon of the fatty acids was derived from ethanol. A leaky adh mutant, S. salivarius MJ 37501, was isolated. The leaky nature of the mutant enabled it to incorporate reduced levels of odd-chain-length fatty acids into its membrane lipids when grown in the presence of 100 mM-propan-1-ol, but not when grown in the presence of 25 mM-propan-1-ol. S. salivarius ATCC 25975 therefore metabolized propan-1-ol (and ethanol) via a constitutive alcohol dehydrogenase.

Low pH-induced membrane fatty acid alterations in oral bacteria

“…When grown at pH 5, the levels of C 14:0 and C 16:0 decreased dramatically to comprise only 38.6% of the total composition (Table 1); there was a simultaneous increase in the levels of C 18:1 and C 20:1 , similar to what was reported in S. mutans [21]. The batch-grown cells had membrane fatty acid profiles similar to the pH 5-grown chemostat cells and to reports published previously [4,[6][7][8][9]. Thus S. salivarius, like S. mutans, increased the proportion of mono-unsaturated membrane fatty acids in response to growth under low pH [21].…”

“…In response to acidification, S. mutans increases the proportion of the long-chained, mono-unsaturated fatty acids (C 18:1 and C 20:1 ) in its membrane with a concomitant decrease in short-chained, saturated fatty acids (C 14:0 and C 16:0 ) as a result of acidification [3]. Although the membrane fatty acid contents of other oral bacteria have been examined, a detailed examination of membrane fatty acid alterations in response to environmental acidification has not been performed [4][5][6][7][8][9][10]. Thus, in order to determine whether membrane fatty acid adaptation is a unique survival mechanism for S. mutans in the oral cavity or a more global, bacterial response, we examined whether this phenomenon occurs in other oral bacteria.…”

Increase of anion and proton permeability of Saccharomyces carlsbergensis plasmalemma by n‐alcohols as a possible cause of its de‐energization

“…The composition of the cell membrane plays an important role in its tolerance to alcohols (Ingram and Buttke, 1984;van Uden, 1985;Hoek and Taraschi, 1988). During the adaptation of microorganisms to the alcohols, the lipid (Ingram and Buttke, 1984;van Uden, 1985;Markevics et al, 1987;Hoek and Taraschi, 1988) and protein (Michel and Starka, 1986;Jimenes and Benitez, 1987) contents of their membranes change.…”

“…According to the present data, the toxic effect of ethanol and other alcohols on the cell is multi-target: they inhibit biosynthesis of macromolecules, activities of glycolytic enzymes and solute transport systems, change the lipid composition of the membranes etc. (Ingram and Buttke, 1984;van Uden, 1985;Michel and Starka, 1986;Dombek and Ingram, 1987;Osman et al, 1987;Cartwright et al, 1986Cartwright et al, ,1987Jimenesand Benitez, 1987;Nabais et al, 1987;Markevics et al, 1987;Calero et al, 1988;Hoek and Taraschi, 1988;Jones, 1988). The major target of alcohol action is the plasma membrane (PM; Ingram and Buttke, 1984;van Uden, 1985;Cartwrightetal., 1986Cartwrightetal., ,1987Jimenes and Benitez, 1987;Markevics et al, 1987;Hoek and Taraschi, 1988).…”

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

“…Adaptation is known to involve enhanced F 1 F 0 -ATPase (H -ATPase) activity [1,2,9,13], as well as enhanced production of an Exo-III-like, DNA-repair enzyme [8]. The responses of oral streptococci to a variety of environmental stresses such as temperature shifts [11,14], alcohols [16] or ionophores [22] involve changes in membrane fatty acid composition. This sort of response is very common among bacteria [5].…”