Search

The sterol fraction of Acanthamoeba (Neff) contains 60% 7-dehydrostigmasterol and 40% ergosterol. The sterols were characterized by infrared and ultraviolet spectroscopy, gas chromatography, specific reactions, and mass spectral analysis. Sterols constitute 5% of the lipids and 15% of the neutral lipids in this species.

Nuclear transplantations and electron microscope autoradiographv (EMRA) were utilized in order to localize and characterize small nuclear RNA's (snRNA) in ameba nuclei. A class of nonmigrating low molecular weight nuclear RNA's is associated with the structureless region of the nucleoplasm but not with the nucleoli, nuclear helices, or chromatin Thus, the role of these RNA's in genetic regulation is questionable A class of migrating RNA's (presumed, but not directly shown, to be low molecular weight) that shuttles between nucleus and cytoplasm is also not associated with nucleoli or helices but some radioactivity is associated with the chromatin It may be, therefore, that the shuttling RNA's are in some way involved in genetic transcription or replication.

The cell surface has been isolated from uninucleate, freshwater, phagocytic amoebae by a new procedure. Several criteria were employed to demonstrate purity of the cell surface fraction. All morphological components of the tripartite surface were present in the isolated surface and the weight of the isolated surface was quantitatively accounted for by the components analyzed. Chemical analyses showed the presence of lipid, protein, and carbohydrate. Mannose was the predominant neutral sugar. Analyses for three different strains of Amoeba were similar. Phosphate was found to be the major anionic group in the cell surface material. Sulfate, uronic acid, sialic acid, muramic acid, and nonamidated glutamic acid and aspartic acid were absent. Evidence is presented suggesting that the phosphate is associated with an unidentified nonreducing polyol.