Abstract
Summary
Tritium, H3 the radioactive isotope of hydrogen has been used for radio-autography and given radioautographic images after a week's exposure of individual yeast cells and paramecia grown in media including sodium acetate containing tritium. Measured radioautographic images of endoplasmic concentrations of radioactivity in paramecium and of individual yeast cells of 3 μ have been delineated. Since the average beta particle from (tritium is absorbed by a micron or less of nuclear track emulsion, from the standpoint of its range, this isotope approaches the ideal for radioautographic localization.
Yeast grown in tritium-containing medium as described and exposed for a shonter time have shown differential localization of tritium in polar and peripheral extranuclear areas. Some of these foci showed only one or two grains of reduced silver (each about 0.3 μ to 0.4 μ) in the emulsion. This probably represents the limit of resolution of radioautography with the present emulsions available for biological experimentts.
We are indebted to the following members of the staff of Sloan-Kettering Institute: Dr. Leonard Hamilton for the paramecium, Dr. H. Christine Reilly for the yeast, and Mr. Mark Gettner for the thin sections.
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