Cytochrome P-450-catalyzed activation of Cyclophosphamide to alkylating metabolites was studied in isolated rat liver microsomes and puri fied, reconstituted P-450 enzyme systems in order to identify the major enzymatic catalysts of drug activation in both uninduced and drug-induced liver tissue. P-450 form PB-4 (P-450 gene UBI) activated Cyclophospha mide with high efficiency [\ „¿ ,», (app...

The nucleoids of microbodies of rat liver cells were isolated in a highly homogeneous and pure state, by treating the microbody-rich fraction, prepared from 10% polyvinylpyrrolidone-0.25 M sucrose homogenate, with Triton X-100. Three treatments with 0.1% detergent were enough to render the nucleoids free from contamination with mitochondria, microsomes, lysosomes, and intact microbodies. Electr...

(1972)1 have concluded from a reassessment of the widely accepted cytological evidence that eukary-otic cells have yet to be found in deposits younger than latest Precambrian. found that the frequency of biparental, or "exceptional," zygotes can be increased up to 50 percent if the mt+ parent is irradiated with ultraviolet light before mating. The term "cytoplasmic gene" is becoming confusing a...

A microplate assay and a thin-layer chromatography (TLC) "in situ" assay based on the Ellman assay was used to screen for acetylcholinesterase inhibitors from ethyl acetate and methanol extracts of Brazilian medicinal plants of families that, according to the literature, have traditional uses that might be connected with acetylcholinesterase inhibition. Eighteen species belonging to Convolvulac...

In respiratory carcinogenesis studies in Syrian golden hamsters, trachea! epithelium is a target tissue for the development of tumors induced by polynuclear aromatic hydrocarbon carcinogens. For evaluation of the capacity for metabolism of these carcinogens in this target tissue, the conversion of the carcinogen benzo(a)pyrene (BP) to polar products was studied in trachea! organ cultures and in...

" This Is an Award for the Entire Field of Cell Biology. " This remark, made by Günter Blobel on American television after winning the 1999 Nobel Prize for Physiology or Medicine, was hardly uncharacteristic: the six-foot, snowy-haired Rocke-feller University professor was typically , generously, extending his prize to all of us who toil 'midst the microscopes. Perhaps more importantly, he was ...