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11.
Victor L. Sylvia Hyeong L. Kim James O. Normanand David L. Busbee 《Cell biology and toxicology》1987,3(1):39-49
Hymenoxon, a toxic sesquiterpene lactone found in bitterweed, bound deoxyguanosine in a cell free system and formed adducts with guanine residues in cellular DNA. The reactive dialdehyde form of hymenoxon formed stable Schiff base products with deoxyguanosine which were separable from unreacted hymenoxon and deoxynucleosides by reverse phase high pressure liquid chromatography. Hymenoxon adducts which eluted as a single impure peak from the octadecylsilane column separated on amino and diphenyl-bonded phases with 10% methanol. Tritiated nucleoside adducts were isolated and purified from CFW mouse sarcoma cells treated with hymenoxon. Proton nuclear magnetic resonance spectra of purified hymenoxon-deoxyguanosine adducts revealed a loss of signals for hydroxyl groups in the bishemiacetal of hymenoxon. 13C-nuclear magnetic resonance spectra revealed that the major adduct has 35 carbon atoms, indicating an interaction of at least two guanine residues per hymenoxon molecule and suggesting that hymenoxon may cross-link DNA. Sedimentation analysis of treated DNA further showed that DNA cross-linking by hymenoxon (30 µg/ml) was equivalent to that of a known cross-linking agent, mitomycin C (7.5 µg/ml). Hymenoxon was more cytotoxic to DNA cross-link repair-deficient Chinese hamster ovary cell mutants than to repair proficient strains. These data combine to indicate that hymenoxon acts as a bifunctional alkylating agent which cross-links DNA in mammalian cells.CHO
Chinese hamster ovary
- HYM
hymenoxon
- MMC
mitomycin C
- NMR
nuclear magnetic resonance
- PBS
phosphate buffered saline 相似文献
12.
Summary After bone marrow transplantation (BMT), it is important to monitor the bone marrow and lymphoid cell populations of the recipient to document engraftment. When donor and recipient are of unlike sex, the sex chromosomes serve as a useful marker to determine cellular origin. When donor and recipient are of like sex, autosomal heteromorphisms can be used to identify the origin of cells in metaphase. Using Q-banding, we found that 17 of 20 patient/donor pairs (85%) examined showed at least one chromosome heteromorphism that distinguished between recipient and donor cells with certainty. Five of the patients were followed up after BMT in order to document engraftment. Donor metaphases could be detected in the marrow within two weeks of BMT when the graft was successful. Chimaerism was detected in the lymphocyte population even when the graft persisted. In a case of graft failure, donor cells did not persist in the marrow, and the lymphocyte population did not convert to donor type. These studies demonstrate that autosomal heteromorphisms are useful in the study of myeloid and lymphoid chimaeric states after BMT. 相似文献
13.
Craighton S. Mauk C. Richard Unrath Sylvia M. Blankenship 《Journal of Plant Growth Regulation》1990,9(1-4):181-184
A rapid, sensitive, and economical chemical analysis of the triazole, gibberellin-inhibitor, paclobutrazol (PP333, [(2RS,3RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4 triazol-1-yl) pentan-3-ol]) was sought, featuring high-performance liquid chromatography (HPLC) as the final quantitation step. Three C18-reverse phase columns (conventional, 250×4.6 mm; cartridge type, 125×4.6 mm; and minicolumn, 33×4.6 mm) were evaluated for their performance in HPLC separation and quantitation of PP333 applied to soil and plant foliage. The 125-mm Whatman Partisil 5 ODS-3 cartridge column was superior to the standard 250-mm DuPont Zorbax ODS unit, and provided enhanced resolution and reduced solvent consumption, analysis time, and cost. A Perkin-Elmer Pecosphere 3×3C-C18 cartridge system was also superior to the 125-mm column with respect to these parameters. Although this minicolumn necessitated an additional purification step prior to HPLC analysis, its exceptionally fast analysis time and recovery period coupled with a high degree of sensitivity rendered it the most superior unit. This HPLC technology provided an efficient means of assaying for PP333 in large-scale experiments dealing with the chemical's absorption, translocation, and physiological response. 相似文献
14.
Activation of a low specific activity form of DNA polymerase alpha by inositol-1,4-bisphosphate 总被引:9,自引:0,他引:9
A low activity form of DNA polymerase alpha immunoaffinity-purified from adult-derived human fibroblasts was activated by interaction with phosphatidylinositol-4-monophosphate, while a high activity form of the enzyme did not interact with phosphatidylinositol-4-monophosphate or its derivatives. Phosphatidylinositol-4-monophosphate was apparently hydrolyzed in the presence of a highly purified low activity form of DNA polymerase alpha, effecting the release of diacylglycerol and the retention of inositol-1,4-bisphosphate by the enzyme complex. The resulting inositol-1,4-bisphosphate/protein complex exhibited increased affinity of binding to DNA template/primer and increased deoxynucleotidyltransferase activity. These data indicate that inositol-1,4-bisphosphate may function as an effector molecule in the activation of a low activity form of human DNA polymerase alpha and suggest that it may function as a second messenger during the initiation of mitosis in stimulated cells. 相似文献
15.
16.
Nurit Eyal Nurit Firon Sylvia Wilder Edwin H. Kolodny Mia Horowitz 《Human genetics》1991,87(3):328-332
Summary Single-stranded cDNA was prepared from RNA obtained from a patient with type 1 Gaucher disease. The cDNA was amplified in vitro and analyzed by sequencing. Three base-pair changes were identified which included a G to C transversion at nucleotide 3119 of the active gene (Asp140His), an A to C transversion at nucleotide 3170 (Lys157Gln) and a G to A change at nucleotide 5309 (Glu326Lys). To study the mode of inheritance of the three different base-pair changes, genomic DNA was prepared from blood or skin fibroblasts of several family members. Genomic glucocerebrosidase DNA sequences were amplified and subjected to hybridization with allele-specific oligonucleotides (ASOs). The hybridization profiles demonstrated that two of the basepair changes originated from the mother and were transmitted to her two affected sons and to a grandchild, while the third base-pair change, originating from the father, was transmitted to his two affected sons, a carrier daughter and a second grandchild. Tests of other patients with Gaucher disease failed to disclose the presence of the three base-changes. This is a unique family with three base-pair changes tightly linked to Gaucher disease. 相似文献
17.
Steady state kinetics were used to examine the influence of Cd2+ both on K+ stimulation of a membrane-bound ATPase from sugar beet roots (Beta vulgaris L. cv. Monohill) and on K+(86Rb+) uptake in intact or excised beet roots. The in vitro effect of Cd2+ was studied both on a 12000–25000 g root fraction of the (Na++K++Mg2+)ATPase and on the ATPase when further purified by an aqueous polymer two-phase system. The observed data can be summarized as follows: 1) Cd2+ at high concentrations (>100 μM) inhibits the MgATPase activity in a competitive way, probably by forming a complex with ATP. 2) Cd2+ at concentrations <100 μM inhibits the specific K+ activation at both high and low affinity sites for K+. The inhibition pattern appears to be the same in the two ATPase preparations of different purity. In the presence of the substrate MgATP, and at K+ <5 mM, the inhibition by Cd2+ with respect to K+ is uncompetitive. In the presence of MgATP and K+ >10 μM, the inhibition by Cd2+ is competitive. 3) At the low concentrations of K+, Cd2+ also inhibits the 2,4-dinitrophenol(DNP)-sensitive (metabolic) K+(86Rb+) uptake uncompetitively both in excised roots and in roots of intact plants. 4) The DNP-insensitive (non metabolic) K+(86Rb+) uptake is little influenced by Cd2+. As Cd2+ inhibits the metabolic uptake of K+(86Rb+) and the K+ activation of the ATPase in the same way at low concentrations of K+, the same binding site is probably involved. Therefore, under field conditions, when the concentration of K+ is low, the presence of Cd2+ could be disadvantageous. 相似文献
18.
Summary 1-Methylguanine and 7-methylguanine, both metabolic products of tRNA degradation, are known to induce transformation of Chinese hamster fibroblasts in culture. The effects of these compounds on the cell membrane have been studied by the method of Concanavalin A-mediated hemadsorption. 1-Methylguanine or 7-methylguanine induced a 50% increase of Con A-mediated hemadsorption within 20 hours of exposure of the cells to the agent at a concentration of 10-5 M. This alteration was reversed within 13 days when the cells were grown in the control medium. Prolonged treatment with 1-methylguanine or 7-methylguanine resulted in changes which were only slowly reversed during growth of the cells in the control medium. The effect of the methylated purines on the cell membrane could be completely inhibited by simultaneous addition of dibutyryl-cAMP at a concentration of 10-5 M. The possible mechanism of cell membrane alteration by methylated purines and its relevance to transformation in vitro are discussed. 相似文献
19.
C A Piantadosi A L Sylvia H A Saltzman F F J?bsis-Vandervliet 《Journal of applied physiology》1985,58(2):665-672
Reflectance spectrophotometry through the skull was used to investigate carbon monoxide (CO) binding by tissue hemoproteins in the brains of barbiturate-anesthetized Sprague-Dawley rats. After splenectomy and extensive perfluorotributylamine exchange transfusion, steady-state spectral scans were obtained in Soret and visible wave-length regions during O2 ventilation, during subsequent exposure to O2-enriched gases containing 1, 3, or 5% CO, and finally after N2 anoxia. These CO exposures were well-tolerated and electroencephalograph (EEG) activity continued to be present. Initial difference spectra were influenced by CO binding to residual hemoglobin, but spectral evidence of CO-mediated b-type cytochrome reduction was obtained in the visible region as CO concentration was increased to 3 or 5%. This was associated with Soret spectra compatible with formation of the reduced cytochrome a3-CO complex. Reduction of cytochrome a at 605 nm and cytochrome c + c1 at 550 nm was absent. These findings may indicate respiratory chain branching through b cytochromes, either to a separate a3-like oxidase independent of the classical cytochrome aa3 or to an unidentified alternative CO-sensitive oxidase. 相似文献
20.
Dr. Moyra M. McConnell Linda V. Thomas Sylvia M. Scotland Bernard Rowe 《Current microbiology》1986,14(1):51-54
A total of 134 enterotoxigenicEscherichia coli (ETEC) of serogroups O25, O27, O148, and O159 were tested in the enzyme-linked immunosorbent assays for the colonization factor antigens I (CFA/I), CFA/II (coli surface antigens CS1, 2 and 3) and putative colonization factor (PCF) 8775 (CS4, 5 and 6). CS6 was detected without CS4 or CS5 in 94% of the strains of serogroup O25, 86% of strains of serogroup O27, 87% of strains of serogroup O148, and 29% of strains of serogroup, O159. The frequency with which CS6 occurs in ETEC of common serotypes without the antigens CS4 or CS5 suggests that it might be a colonization factor. 相似文献