1. Ornithine decarboxylase activity is stimulated in high-density HeLa-cell cultures by dilution of or replacement of spent culture medium with fresh medium containing 10% (v/v) horse serum. 2. After stimulation, ornithine decarboxylase activity reaches a peak at 4-6h, then rapidly declines to the low enzyme activity characteristic of quiescent cultures, where it remains during the remainder of...

Treatment of cultured L1210 cells with the putrescine analogue, 2,5-diamino-3-hexyne, at 0.5 nM resulted in the rapid (1-2 h) appearance of numerous cytoplasmic vacuoles which were highly visible by light microscopy. Ultrastructural examination revealed that the vacuoles contained numerous membrane vesicles and electron-dense structures resembling endosomal elements. Other cellular organelles w...

Rheological Properties Such as Viscosity (η), Shear Stress (τ), and Torque (M) of the mixtures of (HTPB) with Octagon (HMX), Hexogen (RDX), and 2, 6 Diamino-4-Phenyl-1, 3, 5 Triazine (DAPTA) mixtures were measured. The experimental design was arranged for three factors at two levels (High and low levels). Temperature of the mixture (°C), Speed of the stirrer (rpm), Mixing Time (minutes) have be...

A building block approach for the synthesis of α,β-diamino acids is described, which involves the diastereodivergent preparation of two sets of orthogonally protected δ,ε-unsaturated α,β-diamino acids as templates for the preparation of 12 new α,β-diamino acids of biological relevance using simple techniques.

In the title compound, [Fe(CH(3)CN)(3)(C(29)H(27)N(5)OP(2))](BF(4))(2)·2CH(3)CN, the Fe(II) ion is octa-hedrally coordinated by a meridionally chelating tridentate pincer-type PNP ligand derived from 2,6-diamino-4-eth-oxy-1,3,5-triazine and by three acetonitrile mol-ecules. The four Fe-N bond lengths range from 1.9142 (12) to 1.9579 (11) Å, while the Fe-P bonds are 2.2452 (4) and 2.2506 (4) Å [...

Six new mononuclear [FeIII(LBr,Cl)X]-complexes (LBr,Cl is the dianionic penta-N3O2-dentate Schiff base ligand N,N?-bis(2’-hydroxy-3-bromo-5-chlorobenzylidene)-1,6-diamino-3-azahexane; X: Cl?, N3?, NCO?, NCS?, NCSe?, CN?) were synthesized and their structures, magnetic electrochemical properties studied. Structure analysis measurements showed that [FeIII(LBr,Cl)CN] in low spin state other five c...

Neural networks and inductive logic programming (ILP) have been compared to linear regression for modelling the QSAR of the inhibition of E. coli dihydrofolate reductase (DHFR) by 2,4-diamino-5-(substituted benzyl)pyrimidines, and, in the subsequent paper [Hirst, J.D., King, R.D. and Sternberg, M.J.E. J. Comput.-Aided Mol. Design, 8 (1994) 421], the inhibition of rodent DHFR by 2,4-diamino-6,6-...

A series of pyrimido[4,5-b]quinolines (5-deazaflavines), were synthesized by microwave assisted intramolecular cyclization. The N⁴-substituted-2,4-diamino-6-chloro-pyrimidine-5-carbaldehydes, were prepared by selective monoamination of 2-amino-4,6-dichloropyrimidine-5-carbaldehyde with aliphatic and aromatic amines.

In the title compound, 4C(5)H(8)N(3) (+)·2C(8)H(4)O(4) (2-)·C(5)H(7)N(3), the asymmetric unit consists of two protonated diamino-pyridine cations, one phthalate anion and one half of a diamino-pyridine mol-ecule, which has twofold rotation symmetry and is disordered over two positions with a site-occupancy ratio of 0.534 (3):0.466 (3). In the disordered structure, both pyridine rings are essent...

Phosphotungstic acid (which will be designated as PTA) has long been used in separations of the amino acids. It was employed by Drechsel (1) in the discovery of lysine in casein, and by Hausmann (2), by Osborne, Leavenworth, and Brautlecht (3), and by Van Slyke (4-8) for quantitative precipitation of the diamino acids, arginine, lysine, and histidine, in protein hydrolysates. Cystine was found ...