Daunorubicin is biotransformed anaerobically by rat liver microsomes with a reduced nicotinamide adenine dinucleotide phosphate-generating system to form a series of aglycones. The first reaction, reductive cleavage of daunosamine (at C-7 in ring A) to form the 7- deoxyaglycone , is followed by reduction of the C-13 keto group. The 7- hydroxyaglycone may also form by hydrolytic cleavage of the ...

BACKGROUND Cohesion between sister chromatids is promoted by the chromosomal cohesin complex that forms a proteinaceous ring, large enough in principle to embrace two sister strands. The mechanism by which cohesin binds to DNA, and how sister chromatid cohesion is established, is unknown. RESULTS Biochemical studies of cohesin have largely been limited to protein isolated from soluble cellula...

The structure of uleine type alkaloids is characterized by the presence a bridged tetracyclic hexahydro-1H-1,5-methanoazocino[4,3-b]indole ring system 1. Various strategies have been developed to access this polycyclic structural motif. We report herein one-step conversion appropriately functionalized 1,3,4-trisubstituted cyclopent-1-ene 1 way an integrated oxidation/reduction/cyclization (iORC...

As an environmentally-green technology, thermal catalytic oxidation of octachloronaphthalene (CN-75) over anatase TiO2 nanomaterials was investigated at 300 °C. A wide range of oxidation intermediates, which were investigated using various techniques, could be of three types: naphthalene-ring, single-benzene-ring, and completely ring-opened products. Reactive oxygen species on anatase TiO2 surf...

Steroid degradation by Comamonas testosteroni and Nocardia restrictus have been intensively studied for the purpose of obtaining materials for steroid drug synthesis. C. testosteroni degrades side chains and converts single/double bonds of certain steroid compounds to produce androsta-1,4-diene 3,17-dione or the derivative. Following 9α-hydroxylation leads to aromatization of the A-ring accompa...

The dramatic cell shape changes during cytokinesis require the interplay between microtubules and the actomyosin contractile ring, and addition of membrane to the plasma membrane. Numerous membrane-trafficking components localize to the central spindle during cytokinesis, but it is still unclear how this machinery is targeted there and how membrane trafficking is coordinated with cleavage furro...

Calyculin A, a protein phosphatase inhibitor, induced cleavage-like morphological change in unfertilized sea urchin eggs. A contractile ring-like apparatus containing both filamentous actin and myosin was formed in the cleavage furrow. Wheat germ agglutinin receptors were also found in the same region. The eggs did not develop further after constriction of the ring. No aster-like microtubular s...

Isobaric oligosaccharides enzymatically prepared from hyaluronic acid (HA) and N-acetylheparosan (NAH), were distinguished using tandem mass spectrometry. The only difference between the two series of oligosaccharides was the linkage pattern (in HA 1-->3 and in NAH 1-->4) between glucuronic acid and N-acetylglucosamine residues. Tandem mass spectrometry afforded spectra in which glycosidic clea...

Thiazoles and benzothiazoles form part of the molecular structure of many drugs, biocides and industrial chemicals. Examples include 2-mercaptobenzothiazole which is widely used as a rubber accelerator in the manufacture of tyres and which as a consequence occurs in street runoff and esturine sediments [ l ] and which may have ecotoxicological importance. In spite of this widespread occurrence ...