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Rhapidosomes of Saprospira grandis do not contain RNA that is highly methylated at the 2'-oxygen of the sugar residues. Neither is such an RNA associated with the particles as a contaminant. A cursory examination of the rhapidosomes of two other marine organisms gave similar results.

Synthesis of extracellular ribonuclease is induced in cell cultures of Ustilago sphaerogena that are starved for nitrogen and exposed to the gratuitous inducer, 6-mercaptopurine. Cesium, ammonium, or alkylammonium ion represses ribonuclease induction. Addition of citric-acid cycle intermediates to cesium ionrepressed cultures partially restores the rate of ribonuclease synthesis to the induced level. Enzymes involved in assimilation of nitrogen from different sources are also repressed by cesium ion and derepressed by intermediates from the citric acid cycle.