tion were spotted upon Vaseline-impregnated Whatman No. 1 paper and chromatographed. They gave zonea with RP values of 0.25, 0.18, and 0.19, reapectively. Catrrlytic Hydrogenation of an Origid Prepamtion of Vitamin K from M. phlei.-A 2.4-mg sample of an original preparation from M. p?&i was catalytically hydrogenated.A sample of the product, in the quinone form, equivalent to 300 pg of the preparation before reduction, was spotted upon Vaseline-impregnated Whatman No. 1 paper. samples of the correeponding products from vitamin Ko(H) and Kt(M) were also placed upon the paper. The paper chromatogram was developed (descending) for 13 days with glacial acetic acid saturated with Vaseline as solvent. A mixture of the vitamin Kzcw, and Ko(H) reduction produds gave zones 3.6 cm and 7.4 cm, respectively, from the origin.The product from the original preparatidn from M. phlei gave a slightly elongated zone 7.0 cm from the origin.
The kinetics of radiolabeled fatty acid uptake by the ciliate Paramecium tetraurelia was examined on a homologous series of saturated, straight chain fatty acids of even carbon numbers. Uptake rates increased with chain length from acetate to palmitate. Saturation kinetics was demonstrated for most fatty acids examined, thus ruling out simple diffusion as the major mechanism for fatty acid transport and implicating carrier-mediated, facilitated transport as the major mechanism. Data from most competitive inhibition experiments were too scattered to determine the number of transporter systems present. Cholesterol uptake also exhibited saturation kinetics and hence other sterols, which can satisfy this nutritional requirement, may also be transported by a carrier-mediated mechanism. The uptake of the essential fatty acid oleate was faster than those observed for the saturated acids and could not be explained by only one transport mechanism. Therefore, fatty acid transport also occurs via other kinetically significant routes.
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