A. J. Smith, J. London, and R. Y. Stanier (J. Bacteriol. 94:972, 1967) reported that a number of obligate autotrophs, including Thiobacillus thiooxidans and T. thioparus, lacked reduced nicotinamide adenine dinucleotide (NADH2) oxidase activity, although this activity was readily detected in the facultative autotrophs T. intermedius and Hydrogenomonas eutropha. They suggested that the absence o...

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