This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Cooksey, K. E. Search for Related Content PubMed PubMed Citation Articles by Cooksey, K. E. Agricola Articles by Cooksey, K. E.

Articles

The Metabolism of Organic Acids by a Marine Pennate Diatom ¹

^a Rosenstiel School of Marine and Atmospheric Science, Division of Functional Biology, University of Miami, Miami, Florida 33149

Cocconeis diminuta, a marine benthic diatom, metabolizes acetate and lactate-¹⁴C. In the light, the major product was lipid, whereas in the dark, CO₂ was the major product. Analysis of proteins synthesized in the presence of acetate or lactate showed that radioactivity was incorporated predominantly into the glutamate family of amino acids and those amino acids related directly to the substrate. Light and dark assimilation of substrate was inhibited slightly by 3-(3',4'-dichlorophenyl)-1,1-dimethylurea and 2,4-dinitrophenol. 3-(3',4'-Dichlorophenyl)-1,1-dimethylurea caused a pattern of metabolism of acetate in the light characteristic of that which occurs in the dark. Monofluoroacetic acid inhibited assimilation considerably in the dark, but less in the light. The level of enzymes of the tricarboxylic acid cycle and NADH-oxidase were found to be about the same as those in other autotrophs. The metabolism of acetate and lactate is discussed in relation to the autotrophic mode of nutrition of Cocconeis diminuta.