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751.
Does altered nitrogen metabolism and H2O2 accumulation explain the vitrified status of the fully habituated callus of Beta vulgaris (L.)? 总被引:2,自引:0,他引:2
Frédérik Le Dily Claude Huault Thomas Gaspar Jean-Pierre Billard 《Plant Cell, Tissue and Organ Culture》1993,35(1):69-74
The habituated callus is a vitrified tissue which has two main biochemical characteristics both leading to production of toxic forms of oxygen: first the blockage of the porphyrin pathway and a lack of H2O2 detoxifying enzymes (catalase and peroxidases); secondly a deviation of the nitrogen metabolism induced by NH3 accumulation. Ammonia detoxification is ensured by increased glutamate dehydrogenase activity and accumulation of both proline and polyamines. A putative linkage between proline synthesis and the HMP pathway, as proposed for animal proliferating tissues (Phang 1985), might explain a high purine biosynthesis and cytokinin autonomy.Abbreviations FFA
free fatty acids
- 6PG-DH
6-phosphogluconate dehydrogenase
- G6P-DH
glucose-6-phosphate dehydrogenase
- GLU
glutamate
- GDH
glutamate dehydrogenase
- GR
glutathion reductase
- H
habituated callus
- HMP
hexoses-monophosphate
- IAA
indolyl-acetic acid
- LOX
lipoxygenase
- MDA
malondialdehyde
- N
normal callus
- OAT
ornithine aminotransferase
- ORN
ornithine
- PAs
polyamines
- P5C
pyrroline-5-carboxylate
- P5CR
pyrroline-5-carboxylate reductase
- PP-ribose-P
phosphoribosyl pyrophosphate
- SOD
superoxide dismutase 相似文献
752.
Melinda Andrasi Rose Bustos Attila Gaspar Frank A. Gomez Almos Klekner 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2010,878(21):1801-1808
The applicability of micellar electrokinetic capillary chromatography (MEKC) for the analysis of temozolomide (TMZ) and its degradants, 3-methyl-(triazen-1-yl)imidazole-4-carboxamide (MTIC) and 5-amino-imidazole-4-carboxamide (AIC) has been studied. Using short-end injection, the analysis of TMZ and its degradants could be performed within 1.2 min. The obtained precision of migration times was better than 1.6 RSD%, and the limit of quantitation (LOQ) was 0.31–0.93 μg/mL. The therapeutic concentration of TMZ in blood samples can be determined after direct sample injection and conventional on-capillary UV detection. The proposed MEKC method was applied to study the stability of TMZ in water and serum at different pH values. It was established that the half-life of the TMZ in vitro serum at room temperature was 33 min, close to the half-life (28 min) obtained in water at pH 7.9. 相似文献
753.
A GC-ECD titration of IAA in normal auxin (2,4-D)-requiring and auxin-independent (habituated) sugarbeet callus revealed an equal amount in both tissues. A comparison of the content and pattern (through starch gel electrophoresis) of soluble, membrane and wall peroxidases indicated that normal tissues contained a higher level of isoperoxidases. Normal tissues also were found to contain higher levels of peroxidase inhibitors and auxin protectors. The hypothesized peroxidase-mediated higher rate of auxin destruction in normal sugarbeet callus is supposed to be counterbalanced by the 2,4-D-controlled auxin protectors. 相似文献