Figure 3. Sphingolipid and sterol profiles of S. cerevisiae and Z. bailii in response to acetic acid.

Sc: S. cerevisiae cultured in minimal medium. ScAA: S. cerevisiae cultured in minimal medium with 9 g L⁻¹ acetic acid. Zb: Z. bailii cultured in minimal medium. ZbAA: Z. bailii cultured in minimal medium with 24 g L⁻¹ acetic acid. Apparent quantities were calculated relative to the appropriate internal standard, and normalized to the total amount of phosphate in each sample (see Materials and Methods). A. Head group classes of complex sphingolipids. B. Total sphingolipid chain length, presented per lipid, containing two fatty acyl chains. C. Total ceramides and ceramide sub-classes. Abbreviations: DHS: dihydrosphingosine, PHS: phytosphingosine. D. Ergosterol, ergosterol esters and total sterols. *Significant differences, obtained by t-test (P<0.05) compared with control condition (Sc or Zb). The results were calculated from biological replicates (n = 4) and are given as the mean ± standard deviation. For lipid nomenclature, see Table 1.