Fig. 6. Expression profiles of genes regulating ion homeostasis (A,B) and organic osmolyte production (C) during osmotic stress in G. mirabilis gill tissue. (A) Sodium/potassium transporting ATPase -1 chain precursor mRNA (Na⁺, K⁺-ATPase- precursor). (B) Sodium channel protein type IX subunit mRNA (Na⁺ channel XI ). (C) Osmolyte producing enzymes during hyperosmotic stress. Cysteine sulfinic acid decarboxylase mRNA (CSAD; Gm_49c21) catalyzes the rate limiting step in the formation of taurine (triangular symbols). Glutamate decarboxylase mRNA (GluDC) catalyzes the formation of GABA (circular symbols). Inositol monophosphatase mRNA (IMPase) catalyzes the formation of inositol (diamond-shaped symbols). Data points were plotted and labeled as described previously. Filled stars denote significant expression during hyperosmotic stress. Open stars denote significant expression during hypo-osmotic stress. Values are shown ± s.e.m. P<0.05. The expressions of ion homeostasis and organic osmolyte genes not illustrated are described in Table S1C,D, respectively, in supplementary material.