Properties of an Ethionine-Resistant (ER) Mutant of Ochromonas danica |
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Authors: | A. HOCHBERG RACHEL PIMSTEIN M. RAHAT |
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Affiliation: | Dept. of Organic and Biological Chemistry, Hebrew Univ. of Jerusalem, Israel;Dept. of Zoology, Hebrew Univ. of Jerusalem, Israel |
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Abstract: | SYNOPSIS. On prolonged incubation of ethionine-sensitive (ES) cells of Ochromonas danica in L-ethionine-containing media, growth was resumed by an ethionine-resistant (ER) mutant. Such mutants arise at random and are selected by the ethionine-containing medium. Ethionine resistance is not lost on repeated transfers thru ethionine-less media. ES cells incubated with ethionine form a large posterior vacuole before they disintegrate. Inhibition of reserve substance utilization is suggested to underlie growth inhibition of O. danica by ethionine. In ES cells incubated with ethionine, 14C uptake from labeled methionine, ethionine or serine is reduced by 65%. In ER cells the decrease in 14C uptake is 90%. This decrease in uptake of ethionine seems to be how ER O. danica evades growth inhibition by ethionine. |
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