Fig. 1. (A-D) Low pH (pH 6.4) and anoxia in organello increase the stability of mRNA pools during 6 h incubations relative to controls (normoxic, pH 7.8). Isolated mitochondria given both treatments were incubated for the indicated times and RNA was extracted and hybridized on dot blots. Filled circles, controls; filled squares, experimental groups. Data were normalized on a nanogram basis to exogenously added HK standards, and homoskedasticity of standards and samples was assessed using Levene's test. Values are means ± S.E.M. (N=3). HK, hexokinase; CYB, cytochrome b; ND1, NADH dehydrogenase; ATP6, ATP synthase; COX1, cytochrome oxidase. (E-J) Example of a northern blot of total mitochondrial RNA (2 µg) at time 0 (E-G) and 6 h (H-J) for controls (E,H) vs. low pH (F,I) and anoxia (G,J), showing the specificity of the COXI probe against mitochondrial RNA under our experimental conditions.