Coenzyme Q (ubiquinone or Q) is a lipid electron and proton carrier in the electron transport chain. In yeast Saccharomyces cerevisiae eleven genes, designated COQ1 through COQ9, YAH1 and ARH1, have been identified as being required for Q biosynthesis. One of these genes, COQ8 (ABC1) encodes an atypical protein kinase, containing six (I, II, III, VIB, VII, and VIII) of the twelve motifs characteristically present in canonical protein kinases. Here we characterize seven distinct Q-less coq8 yeast mutants, and show that unlike the coq8 null mutant, each maintained normal steady state levels of the Coq8 polypeptide. The phosphorylation states of Coq polypeptides were determined with two-dimensional gel analyses. Coq3p, Coq5p, and Coq7p were phosphorylated in a Coq8p dependent manner. Expression of a human homolog of Coq8p, ADCK3(CABC1) bearing an amino-terminal yeast mitochondrial leader sequence, rescued growth of yeast coq8 mutants on medium containing a nonfermentable carbon source and partially restored biosynthesis of Q 6 . The phosphorylation state of several of the yeast Coq polypeptides was also rescued, indicating a profound conservation of yeast Coq8p and human ADCK3 protein kinase function in Q biosynthesis.

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The intereye difference of cycloplegic refraction was determined in a cohort of 350 rural Japanese schoolchildren aged 6 to 11 years. The intereye spherical difference remained statistically unchanged throughout 5 years, with mean value ranging from 0.21 to 0.28 D, median from 0.15 to 0.20 D, and the 95th percentile from 0.58 to 0.85 D. The prevalence of 1.0 D or greater spherical anisometropia was up to 3.1%. Linear regression analyses of the longitudinal data from individual children revealed that 295 (84.3%) children and remained unchanged while 55 (15.7%) showed significant increase or decrease in the amount of anisometropia with increasing age. The intereye astigmatic difference was also statistically unchangeable, with mean value ranging from 0.28 to 0.36 D, median from 0.20 to 0.39 D, and the 95th percentile from 0.70 to 0.90 D. The prevalence of 1.0 D or greater astigmatic anisometropia was up to 4.3%. There was a significant correlation between the spherical and astigmatic anisometropia. The results show the current state of intereye refractive difference in Japanese schoolchildren, demonstrating that it remains unchanged and significant anisometropia is rare during school age.

We performed a 5 year longitudinal study of cycloplegic refraction in a cohort of 350 Japanese schoolchildren from 6 to 11 years of age in a rural area of southwestern Japan. The spherical refraction was measured under cycloplegia with an infrared autorefractometer. The grouped data from 350 right eyes showed leptokurtic frequency distributions, and the median was +0.91 D at age 6 yrs, shifted towards emmetropia with increasing age and reached +0.34 D at age 11 years. The prevalence of myopia of -1.0 D or more was 0.3%, 0.6%, 2.0%, 2.6%, 2.9%, and 4.9% from age 6 to 11 years, and the prevalence of myopia of more than -2.0 D was less than 1% at age 6-9 years and thereafter increased up to 6.0% at age 11 years. Linear regression analysis for the longitudinal refractive data revealed that 247 (70.6%) of the 350 eyes exhibited first-order linear decrease in hyperopia or increase in myopia with an average annual change of -0.15 D/year, 14 (4%) showed second-order curvilinear change, and 89 (25.4%) remained unchanged. In the eyes with linear change, there was a significant relationship between the refraction at age 6 years and the rate of subsequent change such that the less hyperopic or emmetropic at age 6 years, the larger the change. The refraction at birth was estimated by extrapolation of the linear regression analysis results, implying that 88% of newborns have hyperopia of +1.0 D or greater and myopia is rare. These results indicate the current state of refraction in Japanese schoolchildren of a rural area.