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51.
Kinetic analyses were performed on the nonphosphorylated and in vitro phosphorylated forms of recombinant Sorghum C4 phospho enolpyruvate carboxylase (C4 PEPC). The native enzyme was purified by immunoaffinity chromatography and its integrity demonstrated by Western blot analyses using anti N- and C-terminus antibodies. At suboptimal pH (7.1 to 7.3) and PEP concentration (2.5 mM), phosphorylation, positive metabolite effectors e.g., glucose-6-phosphate, glycine and dihydroxyacetone-phosphate, or an increase in pH strongly activated the enzyme and lowered the inhibitory effect of L-malate. C4 PEPC phosphorylation strengthened the effect of the positive effectors thereby decreasing further the enzyme's sensitivity to this inhibitor. L-malate also decreased the phosphorylation rate of C4 PEPC, a process antagonized by positive metabolite effectors. This was shown both in vitro, in a reconstituted phosphorylation assay containing the catalytic subunit of a cAMP-dependent protein kinase or the Sorghum leaf PEPC-PK and in situ, during induction of C4 PEPC phosphorylation in mesophyll cell protoplasts. 相似文献
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The study assesses the influence of different concentrations of nitrogen and phosphorus sources on ginsenoside biosynthesis in Panax quinquefolium hairy roots cultivated in shake flasks and a nutrient sprinkle bioreactor. The saponin content was determined using HPLC. The maximum yield (12.45 mg g?1 dw) of the sum of six examined ginsenosides (Rb1, Rb2, Rc, Rd, Re and Rg1) in hairy roots cultivated in shake flasks was achieved in modified Gamborg B-5 medium containing 0.83 mM l?1 phosphate, 12.4 mM l?1 nitrate and 0.5 mM l?1 ammonium. The yield itself was 1.93 times higher than that achieved in standard Gamborg medium. The modified medium also favourably influenced the biosynthesis of studied saponins in bioreactor cultures. The saponin content (35.11 mg g?1 d.w.) was 2.75-times higher than that achieved in control medium. 相似文献
56.
V D Chivanov A K Mishnev S A Alsenov V I Eremenko I A Eremenko N G Zdo?ma 《Biofizika》1999,44(2):203-207
The study of homo- and heterocluster quasimolecular ions of 20 L-amino acids (A) and five dipeptides by the TOF-PDMS method indicated that the intensity of quasimolecular ions of the corresponding homo-([An + H]+ and [Bm + H]+, where A and B are biomolecules (A, dipeptides), n and m = 1 .... 5) and heteroclusters ([An.Bm + H]+, n and m = 1 .... 5) depends mainly on the hydrophobicity of the constituents of the A cluster. The most intensive peaks of homo- and heterocluster ions were obtained for hydrophobic amino acids: L-Ile, L-Leu, L-Val, and L-Phe, and for dipeptides containing these amino acids. The assumption is made that the stereochemical parameters of heterocluster quasimolecular ions in the TOF-PDMS method are determined by the physicochemical mechanisms involved in the processes of ionization/desorption of biomolecules and do not reflect directly biologically significant interactions of biomolecules in vivo. 相似文献
57.
S Claustre F Bringaud L Azéma R Baron J Périé M Willson 《Carbohydrate research》1999,315(3-4):339-344
1-Amino-2,5-anhydro-1-deoxy-D-mannitol and a series of arylamino derivatives were prepared by nitrous acid deamination of 2-amino-2-deoxy-D-glucose and subsequent reductive amination of the resulting 2,5-anhydro-D-mannose. Some of these compounds showed an enhanced affinity for the hexose transporter of Trypanosoma brucei as compared to D-fructose. 相似文献
58.
Kurt W. Alt Sandra Pichler Werner Vach Bohuslav Klíma Emanuel Vl
ek Jurg Sedlmeier 《American journal of physical anthropology》1997,102(1):123-131
In 1986 a palaeolithic triple burial was discovered near Dolní Věstonice (Czech Republic). The occurrence of anatomic variants in all three skeletons gave rise to speculations that the buried individuals may have been closely related. To test this hypothesis the skeletons were submitted to a systematic kinship analysis based on odontologic and other non-metric traits. Statistical tests showed that the coincident occurrence of several rare traits in the individuals is highly unlikely to occur at random. This and further data included in the analysis therefore suggest that the three individuals buried together were genetically related and actually belonged to one family. Am J Phys Anthropol 102:123–131. © 1997 Wiley-Liss, Inc. 相似文献
59.
White rot fungi (WRF) are applicable to biodegradation of recalcitrant pollutants. However, excessive biomass growth typical for WRF cultivation can hinder their large scale applications. Therefore, immobilization of Irpex lacteus to liquid-core alginate beads restricting excessive mycelium growth and simultaneously keeping high degradation rate of pollutants was tested. Effective diffusivities of dyes to the beads varied from (2.98 ± 0.69) × 10?10 to (10.27 ± 2.60) × 10?10 m2/s. Remazol Brilliant Blue R (RBBR), Reactive Orange 16 (RO16), and Naphthol Blue Black (NBB) were used as model dyes. The immobilized fungus decolorized model dyes when applied both in microwell plates and in fluidized bed reactors. Using the microwell plates, the apparent reaction rate constants ranged from (2.06 ± 0.11) × 10?2 to (11.06 ± 0.27) × 10?2 1/h, depending on the dye used and its initial concentration. High initial concentrations negatively affected the dye decolorization rate. No fungal growth outside the beads was observed in fluidized bed reactors and thus no operational problems linked to an excessive biomass growth occurred. When RBBR was decolorized in subsequent batches in the fluidized bed reactor, the apparent reaction rate constant increased from (11.63 ± 0.35) × 10?2 to (29.26 ± 7.19) × 10?2 1/h. 相似文献
60.
Símová S Klíma M Cermak L Sourková V Andera L 《Apoptosis : an international journal on programmed cell death》2008,13(3):423-436
TRAIL, a ligand of the TNFα family, induces upon binding to its pro-death receptors TRAIL-R1/DR4 and TRAIL-R2/DR5 the apoptosis
of cancer cells. Activated receptors incite the formation of the Death-Inducing Signaling Complex followed by the activation
of the downstream apoptotic signaling. TRAIL-induced apoptosis is regulated at multiple levels, one of them being the presence
and relative number of TRAIL pro- and anti-apoptotic receptors on the cytoplasmic membrane. In a yeast two-hybrid search for
proteins that interact with the intracellular part (ICP) of DR4, we picked ARAP1, an adapter protein with ArfGAP and RhoGAP
activities. In yeast, DR4(ICP) interacts with the alternatively spliced ARAP1 lacking 11 amino acids from the PH5 domain.
Transfected ARAP1 co-precipitates with DR4 and co-localizes with it in the endoplasmic reticulum/Golgi, at the cytoplasmic
membrane and in early endosomes of TRAIL-treated cells. ARAP1 knockdown significantly compromises the localization of DR4
at the cell surface of several tumor cell lines and slows down their TRAIL-induced death. ARAP1 overexpressed in HEL cells
does not affect their TRAIL-induced apoptosis or the membrane localization of DR4, but it enhances the cell-surface presentation
of phosphatidyl serine. Our data indicate that ARAP1 is likely involved in the regulation of the cell-specific trafficking
of DR4 and might thus affect the efficacy of TRAIL-induced apoptosis.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献