FIG. 6.

The expression of genes involved in Ysa TTS is affected by pH. Levels of β-galactosidase expression were measured for selected strains cultivated at 26 and 37°C in L medium plus 290 mM NaCl buffered at various pH values as indicated below each panel. (A) GY4641 (ysaE-lacZYA); (B) GY4668 (orf6 orf7-lacZYA); (C) GY4639 (ysaR-lacZYA); (D) GY4664 (ysaU-lacZYA); (E) GY4894 (ysrS-lacZYA); (F) GY5019 (sycB-lacZYA). Media were buffered at pH 5.0 with 100 mM citrate, at pH 6.0 with 100 mM MES, at pH 7.0 with 100 mM MES, and at pH 8.0 with 100 mM MOPS. White bars represent results for cultures cultivated at 26°C, and gray bars represent results for cultivation at 37°C. β-Galactosidase expression was determined when cultures reached the early to mid log phase of growth. The results represent averages ± standard deviations from two independent experiments performed in duplicate.