l’ctmhymena g&ii II, a holotrichous protozoan, was isolated as a bacteria-free culture in 1931 by Dr. Alford Hetherington at Pacific Grove, California. The culture of the ciliate employed in the present studies was obtained in 1945 through the courtesy of Dr. George W. Kidder, who had received a culture from Dr. R. H. Hall in 1938 (2). Hetherington named this microorganism Colpidium campylum, b...

Information readout in the DNA minor groove is accompanied by substantial DNA deformations, such as sugar switching between the two conformational domains, B-like C2'-endo and A-like C3'-endo. The effect of sugar puckering on the sequence-dependent protein-DNA interactions has not been studied systematically, however. Here, we analyzed the structural role of A-like nucleotides in 156 protein-DN...

The arylidienes of spiro thiazolidines (5) containing α,β-unsaturated function have been used as component of Micheal addition with equimolar amount of 2-aminopyridine (6a) to give novel spiro [indole-3,2′-pyrido[1,2-a]thiazolo[5,4-e]pyrimidines] (7) in a single step under microwaves in presence of montmorillonite KSF as solid support. The new improved synthetic method for spiro [indole-3, 2′-t...

The incorporation in vivo of compounds labeled with N15 or Cl4 into the purines and pyrimidines of nucleic acid has been repeatedly demonstrated (e.g. (l-3)). W e wish to report observations on the incorporation of radioactive erotic acid in vitro into the pyrimidines of the nucleic acid of rat liver slices. It is believed that this procedure will readily permit the study of precursors of nucle...

Sulphanilamide inhibition of the growth of certain yeasts and yeastlike organisms was overcome in a non-competitive manner by methionine, adenine and histidine, which are therefore regarded as end-products of enzyme systems for which p-aminobenzoic acid is essential. The methionine system was the most sensitive to sulphanilamide, followed in order by those of adenine and histidine. In the prese...

Rhizobia require the availability of 20 amino acids for the establishment of effective symbiosis with legumes. Some of these amino acids are synthesized by rhizobium, whereas the remaining are supplied by the host plant. The supply from plant appears to be plant-type specific. Alfalfa provides arginine, cysteine, isoleucine, valine and tryptophan, and cowpea and soybean provide histidine. The p...