0.2 IIg. suspended in lecithin-saline administered intraperitoneally to a mouse of ca. 20 g. Carbon.Skeletons and Oxygept Functions.-Oenanihotoxiii and cicutoxin are diols, oenanthetol and cicutol alcohols, and oenanthetone is an unconjugated ketone. The oxygen functions were disclosed by the usual reagents but the products were very difficult

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A technic is described for high resolution intracellular autoradiography in the electron microscope. Cultures of LLC-MK2 monkey kidney cells were incubated for 72 hours in a medium containing 0.4 #curie per ml of thymidine-H 3. After labeling, the cells were fixed with osmium tetroxide and embedded in methacrylate. Ultrathin sections of the labeled tissue were taken up on Formvar-coated and carbon-stabilized electron microscope grids. A 150 to 450 A layer of silver metal was then evaporated onto the tissue. The coated grids were exposed to bromine vapor for 1.5 to 2 minutes under red light, allowed to dry for 1 minute, and then covered with a thin film of 1 per cent aqueous gelatin applied by means of a fine wire loop lowered over the grid supported on a glass peg. For autoradiographic exposure, the grids were stored 50 days in a light-proof container at 4°C with calcium chloride desiccant. Development was carried out for 5 minutes at 20°C in Promicrol (May and Baker, England) diluted 1 : 1 with water, followed by a 1 minute water wash and fixation for 2.5 minutes in 15 per cent aqueous sodium thiosulphate. After removal of the gelatin by immersion for 16 hours in water at 37°C, the autoradiograms were dried and examined in the electron microscope. Uhrastructural detail was fairly well defined and the cytoplasm of each labeled cell was covered with an electron opaque deposit of silver, suggesting that a polynucleotide containing thymidine may be synthesized in the cytoplasm. The matter is discussed.

A method has been devised for the quantitative determination of malonaldehyde in oxidized fish oils by means of the 2-thiobarbituric acid reagent in alcoholic solution. TBA numbers and peroxide values have been determined at intervals during hydroperoxidation of pilchard oil. The curves follow the same general pattern but the numerical relationship between them depends upon the temperature of oxidation.In alcoholic solution, the reaction between thiobarbiturie acid and malonaldehyde is carried out in the dark, because sunlight causes a decrease in optical density of the TBA-malonaldehyde complex at 532 mt~ with the appearance of a second maximum at 452 m~. The nature of the compounds responsible for absorption at these two wave-lengths is discussed.

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