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71.
Recombinant human Factor IX (rFIX) was cloned in a mammalian expression vector and transfected into CHO and HEK-293. Treatment
with 10−9 M methyl testosterone increased rFIX production by 30–50% in CHO and HEK clones. However, 10−9 M 17β-oestradiol increased production of rFIX by ~50% in CHO-F7 clone and decreased production by 48% and 37% in CHO-F8 and
HEK-F2-6, respectively. Progesterone treatment inhibited rFIX production in both cell lines. Production of rFIX can thus be
increased by sex hormone treatment and therefore used to enhance biotechnological production in mammalian cells. 相似文献
72.
Plant receptor proteins are involved in the signaling networks required for defense against pathogens. The novel pepper pathogen-induced gene CaMRP1 was isolated from pepper leaves infected with Xanthomonas campestris pv. vesicatoria (Xcv). This gene is predicted to encode a membrane-located receptor-like protein that has an N-terminal signal peptide and a C-terminal transmembrane helix. A CaMRP1-GFP fusion protein localized primarily to the plasma membrane of plant cells. Strong and early induction of CaMRP1 expression occurred following exposure of pepper plants to Xcv, Colletotricum coccodes, methyl jasmonate (MeJA) and wounding stress. Virus-induced gene silencing (VIGS) of CaMRP1 in pepper conferred enhanced basal resistance to Xcv infection, accompanied by induction of genes encoding basic PR1 (CaBPR1), defensin (CaDEF1) and SAR8.2 (CaSAR82A). In contrast, CaMRP1 overexpression (OX) in transgenic Arabidopsis plants resulted in increased disease susceptibility to Hyaloperonospora parasitica infection. Arabidopsis plants overexpressing CaMRP1 exhibited insensitivity to MeJA by causing reduced expression of MeJA-responsive genes. Overexpression also resulted in tolerance to NaCl and during salt stress, the expression of several abscisic acid-responsive genes was induced. Together, these results suggest that pepper CaMRP1 may belong to a new subfamily of membrane-located receptor-like proteins that regulate disease susceptibility, MeJA-insensitivity and salt tolerance. 相似文献
73.
Diana M. Cheng Gad G. Yousef Mary H. Grace Randy B. Rogers J. Gorelick-Feldman I. Raskin Mary Ann Lila 《Plant Cell, Tissue and Organ Culture》2008,94(1):73-83
In order to develop a sustainable source of metabolism-enhancing phytoecdysteroids, cell suspension and hairy root cultures
were established from shoot cultures of wild-harvested Ajuga turkestanica, a medicinal plant indigenous to Uzbekistan. Precursors of phytoecdysteroids (acetate, mevalonic acid cholesterol) or methyl
jasmonate (an elicitor) were added to subculture media to increase phytoecdysteroid accumulation. In cell suspension cultures,
20-hydroxyecdysone (20E) content increased 3- or 2-fold with the addition of 125 or 250 μM methyl jasmonate, respectively,
compared to unelicited cultures. Precursor addition, however, did not provoke phytoecdysteroid accumulation. In hairy root
cultures, addition of sodium acetate, mevalonic acid, and methyl jasmonate, but not cholesterol, increased phytoecdysteroid
content compared to unelicited cultures. Hairy root cultures treated with 150 mg l−1 sodium acetate, or 15 or 150 mg l−1 mevalonic acid, increased 20E content approximately 2-fold to 19.9, 20.4 or 21.7 μg mg−1, respectively, compared to control (10.5 μg mg−1). Older hairy root cultures, extracted after the seventh subculture cycle, also showed increases in 20E content (24.8 μg mg−1), turkesterone (0.9 μg mg−1) and cyasterone (8.1 μg mg−1) compared to control cultures maintained for a shorter duration of four subculture cycles. Doses of 10 or 20 μg ml−1 hairy root extract increased protein synthesis by 25.7% or 31.1%, respectively, in a C2C12 mouse skeletal cell line. These
results suggest that sustainable production of metabolically active phytoecdysteroid can be achieved through hairy root culture
systems.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
74.
To develop an optimal bioprocess for secondary metabolite production and explain the bioprocess at the molecular level, we examine the synergistic effects of sequential treatment with methyl jasmonate (MJ), salicylic acid (SA) and yeast extract (YE) on benzophenanthridine alkaloid accumulation and protein expression in Eschscholtzia californica suspension cultures. Serial treatment of MJ, SA and YE at 24 h intervals enhanced the accumulation of dihydrosanguinarine (2.5 times) and sanguinarine (5.5 times). This sequential treatment using different signal elicitors was more effective than single elicitor or simultaneous treatment of the elicitors; it induced benzophenanthridine alkaloid accumulation to 917.7 ± 42.0 mg/L. Also, (S)-methylcoclaurine-3′-hydroxylase (CYP80B1) and 3′-hydroxy-(S)-N-methylcoclaurine-4′-O-methyltransferase (4′OMT) expressions among enzymes in sanguinarine biosynthetic pathway explained the synergistic effects by sequential treatment of the elicitors. The sequential treatment strategy using elicitors related to different signal transduction pathways can be used to design better processes to increase accumulation of secondary metabolites in plant cell culture. Analysis of protein expression provides the detailed information about metabolite accumulation through the correlated results. 相似文献
75.
We describe here the synthesis of the allyl Lea trisaccharide antigen as well as that of an analogue of the Lex trisaccharide antigen, in which the galactose residue has been replaced by a glucose unit. Although successful fucosylations at O-4 of N-acetylglucosamine acceptors have been reported using perbenzylated thioethyl fucosyl donors under MeOTf activation, such conditions led in our case to the conversion of our acceptor to the corresponding alkyl imidates. Indeed, in this synthesis of the Lea analogue, we demonstrate that the temporary protection of the N-acetyl group as a methyl imidate is advantageous to fucosylate at O-4. In contrast, we report here that glucosylation at O-4 of an N-acetylglucosamine monosaccharide acceptor using the α-trichloroacetimidate of peracetylated glucopyranose as a donor proceeded in better yields under activation with excess BF3·OEt2 than that of the corresponding methyl imidate. Therefore, we conclude that activation of thioglycoside donors by MeOTf to glycosylate at O-4 of a glucosamine acceptor is best accomplished following the temporary protection of the N-acetyl group as a methyl imidate, especially when the donors are highly reactive and prone to degradation. In contrast, if donor and acceptor can withstand multiple equivalents of BF3·OEt2, glycosylations at O-4 of a glucosamine acceptor with a trichloroacetimidate donor does not benefit from the temporary protection of the N-acetyl group as a methyl imidate. 相似文献
76.
Two major volatiles produced by the mycelia and fruiting bodies of Tricholoma matsutake (1-octen-3-ol and methyl cinnamate) repel a mycophagous collembolan, Proisotoma minuta. Aggregation of the collembolans on their diet was significantly inhibited by exposure to 1 ppm methyl cinnamate or 10 to
100 ppm 1-octen-3-ol. The aggregation activity decreased dose-dependently upon exposure to 1-octen-3-ol at concentrations
higher than 0.01 ppm. Aggregation in the presence of methyl cinnamate exhibited three phases: no significant effect at concentrations
ranging from 0.001 to 0.1 ppm, significant inhibition from 1 to 100 ppm, and strong inhibition at 1,000 ppm. These results
may explain why certain collembolan species do not prefer T. matsutake fruiting bodies. 相似文献
77.
KRISHNA L. BHAT WILLIAM H. BRENDLEY CHARLES W. BOCK 《Soil & Sediment Contamination》2004,13(3):267-281
Computational studies using density functional theory can help define which of a variety of reactions may be involved in the degradation of the fuel oxygenate methyl tert-butyl ether (MTBE). It is shown that hydrolysis of MTBE in the vapor phase or in neutral aqueous media, as well as its unimolecular decomposition, are not significant degradation mechanisms. The acid catalyzed hydrolysis of MTBE is a more feasible degradation pathway and is shown to proceed via tert-butyl carbonium ion formation. Hydrogen abstraction is shown to be the dominant first step in the degradation of MTBE initiated by hydroxyl radicals. 相似文献
78.
Jasmonates Inhibit Flowering in Short-Day Plant Pharbitis nil 总被引:1,自引:0,他引:1
Beata Daria Maciejewska Jacek Kesy Marlena Zielińska Jan Kopcewicz 《Plant Growth Regulation》2004,43(1):1-8
The role of jasmonates in the photoperiodic flower induction of short-day plant Pharbitis nil was investigated. The plants were grown in a special cycle: 72 h of darkness, 24 h of white light with lowered intensity, 24-h long inductive night, 14 days of continuous light. At 4 h of inductive night the cotyledons of non-induced plants contained about two times the amount of endogenous jasmonates (JA/JA-Me) compared to those induced. A 15-min long pulse of far red light (FR) applied at the end of a 24-h long white light phase inhibited flowering of P. nil. The concentration of jasmonates at 2 and 4 h of inductive night in the cotyledons of the plants treated with FR was similar. Red light (R) could reverse the effect of FR. R light applied after FR light decreased the content of jasmonates by about 50%. Methyl jasmonate (JA-Me) applied to cotyledons, shoot apices and cotyledon petioles of P. nil inhibited the formation of flower buds during the first half of a 24-h long inductive or 14-h long subinductive night. Application of JA-Me to the cotyledons was the most effective. None of the plants treated with JA-Me on the cotyledons in the middle of the inductive night formed terminal flower buds. The aspirin, ibuprofen and phenidone, jasmonates biosynthesis inhibitors partially reversed the effect of FR, stimulating the formation of axillary and terminal flower buds. Thus, the results obtained suggests that phytochrome system control both the photoperiodic flower induction and jasmonates metabolism. Jasmonates inhibit flowering in P. nil. 相似文献
79.
80.