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51.
Summary Gamma irradiation and ethanol stress treatments redirected pollen development to an embryo formation pathway inBrassica napus. Less than 0.01% of microspores developed into embryos at 25°C compared to approximately 2% at 32°C. However, subsequent
to gamma irradiation and ethanol treatments up to 1% and 0.7% of microspores formed embryos at 25°C, respectively. Gamma irradiation
also enhanced embryogenesis at 32°C. The possible importance of these findings is discussed in relation to microspore embryogenesis. 相似文献
52.
Study of the in vitro bioactivation of albendazole in human liver microsomes and hepatoma cell lines
Sylvie Rolin Hajar Souhaili-El Amri Anne-Marie Batt Michele Levy Denyse Bagrel Gerard Siest 《Cell biology and toxicology》1989,5(1):1-14
The metabolism of albendazole (ABZ), a benzimidazole anthelminthic, was studied in either microsomal preparations of human liver biopsies or cultured human hepatoma cell lines. Metabolites were analyzed by HPLC. Our data show that microsomes from human biopsies and two human cell lines, HepG2 and Hep3B, oxidize the drug to the sulfoxide very efficiently, whereas the third cell line tested, SK-HEP-1, does not. Both cytochrome P-450 dependent monooxygenases and favin-containing monooxygenases appear to be involved in human ABZ metabolism. Using the cell line displaying the highest ABZ-metabolizing activity, HepG2, the cytotoxic and the inducing effects of the parent drug ABZ and of two primary metabolites, the sulfoxide and the sulfone were studied. These three chemicals provoked a rise in mitotic index resulting from cell division blockage at the prophase or at the metaphase (ABZ metabolites) stage, and ABZ was more cytotoxic than its metabolites. With regard to enzyme-inducing effects, our data clearly demonstrate that the sulfoxide and, to a lesser degree, the sulfone are potent inducers of some drug metabolizing enzymes (i.e., cytochrome P-488 dependent monooxygenases and UDP glucuronyltransferase), whereas ABZ fails to increase and even slightly decreases these enzymatic activities. In conclusion, the HepG2 human hepatoma cell line appears to be suitable for the study of many parameters of metabolism and action of ABZ and other structurally related compounds in humans.Abbreviations ABZ
albendazole
- B[a]P
benzo[a]pyrene
- HPLC
high-performance liquid chromatography
- MC
3-methylcholanthrene
- MFO
mixed-function oxidase
- UDPGT
UDP-glucuronyltransferase 相似文献
53.
J. F. Ghersi-Egea A. Minn J. L. Daval Z. Jayyosi V. Arnould H. Souhaili-El Amri G. Siest 《Neurochemical research》1989,14(9):883-887
NADPH:cytochrome P-450 (c) reductase is a microsomal enzyme which is involved in the cytochrome P-450-dependent biotransformation of many exogenous agents as well as of some endogenous molecules. Using cytochromec as a substrate, the kinetic parameters of this enzyme were determined in brain microsomes. The comparison of the NADPH:cytochrome P-450 reductase's Vmax values and cytochrome P-450 contents in both fractions, suggests a role of cerebral NADPH:cytochrome P-450 reductase in cytochrome P-450 independent pathways. This is also supported by the different developmental pattern of brain enzyme as compared to the liver enzyme, and by the presence of a relatively high NADPH:cytochrome P-450 reductase activity in immature rat brain and neuronal cultures, while cytochrome P-450 was hardly detectable in these preparations. The enzyme activity was not induced by a phenobarbital chronic treatment neither in the adult brain nor in cultured neurons, suggesting a different regulation of the brain enzyme expression. 相似文献
54.
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56.
U. Gartenbach-Scharrer S. Habib K. -H. Neumann 《Plant Cell, Tissue and Organ Culture》1990,22(1):27-35
Freshly isolated explants of the secondary phloem of carrot roots were exposed to 14C-leucine for various periods from t0—to 18 h and the 14C labelling of protein was studied by 2-dimensional PAGE followed by fluorograph. The labelling pattern of proteins indicated a sequential activation of synthesis of about 130 proteins during the 18 h experimental period prior to the onset of cell division activity.Abbreviations IAA
indole acetic acid
- 2iP
2-isopentenyladenine
- PVP
polyvinylpyrrolidone
- CBB
Coomassie brilliant blue
- RuBPCase
ribulosebisphosphate carboxylase
- LSC
liquid scintillation counter
- spec.act.
specific radioactivity
- u.l.
uniformly labelled 相似文献
57.
Induction of callus and plant regeneration in Vicoa indica 总被引:1,自引:0,他引:1
Callus cultures were initiated from the stem and leaf explants of aseptically grown Vicoa indica. A simple method is described for plant regeneration from callus and the rapid multiplication of the plants thus obtained. Callus initiation was optimum in Gamborg B5 (B5) basal medium containing either 2.0 mg l-1 naphthaleneacetic acid (NAA) with 0.2 mg l-1 kinetin (Kn) or 2.0 mg l-1 6-benzylaminopurine (BAP) with 0.2 mg l-1 NAA. The calli initiated on B5 medium were able to proliferate on both Murashige and Skoog (MS) and B5 basal medium. Shoot primordia were obtained from greenish callus on passage to B5 basal medium containing 3.0 mg l-1 BAP and 1.0 mg l-1 Kn. On further subculture onto B5 medium containing 0.2 mg l-1 Kn the shoot primordia developed into plantlets. 相似文献
58.
Induction of Haem Oxygenase as a Defence Against Oxidative Stress 总被引:17,自引:0,他引:17
Roland Stocker 《Free radical research》1990,9(2):101-112
Cells respond to metabolic perturbations by producing specific stress proteins. Exposure of mammalian cells to various forms of oxidative stress induces haem oxygenase, the rate-limiting enzyme in haem degradation. This response is proposed to represent an antioxidant defence operating at two different stages simultaneously. It (i) decreases the levels of the potential pro-oxidants haem and haem proteins such as cytochrome P-450 and protoporphyrinogen oxidase, and (ii) increases the tissue concentrations of antio-xidatively active bile pigments. 相似文献
59.
Dahlia Minc-Golomb Gal Yadid Ilan Tsarfaty James H. Resau Joan P. Schwartz 《Journal of neurochemistry》1996,66(4):1504-1509
Abstract: In the CNS, nitric oxide (NO) functions as both neuromodulator and neurotoxic agent. In vivo neuronal expression of NO synthase (NOS) has been attributed to constitutive NOS—both the neuronal and the endothelial types. The other class of NOS—the inducible NOS (iNOS)—is known to mediate toxic effects of NO in various tissues. In this study, we show for the first time that direct intracerebellar injection of endotoxin and cytokine (lipopolysaccharide and interferon-γ) induced in vivo neuronal expression of the iNOS gene, as demonstrated by fluorescent in situ hybridization and immunohistochemical staining analyzed by confocal laser-scanning microscopy. This raises the possibility that neuronal iNOS might contribute significantly to the vulnerability of the brain to various insults. 相似文献
60.