Search

Using C/sup 14/ samples absorbed on thin paper discs, the apparent radioactivity of samples of glycine and hemin was measured in a gas-flow counter over a wide range of specimen thickess. Results show that specimens ranging up to a thickness of 150 mu g/cm/sup 2/ may be regarded as approximately infinitely thin. It is estimated that the count rate is decreased by approximately 20% as a result of absorption of the radioactivity by the paper. To a considerable extent, the change in count rate due to self-absorption varies as the reciprocal of a linear function of the thickness of both the paper and the specimen. (auth)

Separation of simple saturated hydroxamic acids with a chain length of one to nine carbon atoms has been achieved by partition chromatography on paper. The relative merits of a number of solvents are discussed.

A unicellular blue-green alga, Agmenellum quadruplicatum , and a filamentous blue-green alga, Lyngbya lagerheimíi , were grown heterotrophically in dim light with glucose as major source of carbon and possibly energy. The dim-light conditions did not support autotrophic growth. The two blue-green algae appeared to have the same metabolic block, namely an incomplete tricarboxylic acid cycle, as has been found in other obligately phototrophic blue-green algae. Under dim-light conditions, glucose made a greater contribution to cell constituents (amino acids) of A. quadruplicatum and L. lagerheimii than under high-light conditions.