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101.
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PHA production, from bacteria to plants. 总被引:5,自引:0,他引:5
H E Valentin D L Broyles L A Casagrande S M Colburn W L Creely P A DeLaquil H M Felton K A Gonzalez K L Houmiel K Lutke D A Mahadeo T A Mitsky S R Padgette S E Reiser S Slater D M Stark R T Stock D A Stone N B Taylor G M Thorne M Tran K J Gruys 《International journal of biological macromolecules》1999,25(1-3):303-306
The genes encoding the polyhydroxyalkanoate (PHA) biosynthetic pathway in Ralstonia eutropha (3-ketothiolase, phaA or bktB; acetoacetyl-CoA reductase, phaB; and PHA synthase, phaC) were engineered for plant plastid targeting and expressed using leaf (e35S) or seed-specific (7s or lesquerella hydroxylase) promoters in Arabidopsis and Brassica. PHA yields in homozygous transformants were 12-13% of the dry mass in homozygous Arabidopsis plants and approximately 7% of the seed weight in seeds from heterozygous canola plants. When a threonine deaminase was expressed in addition to bktB, phaB and phaC, a copolyester of 3-hydroxybutyrate and 3-hydroxyvalerate was produced in both Arabidopsis and Brassica. 相似文献
104.
Jetter MC McNally JJ Youngman MA McDonnell ME Dubin AE Nasser N Zhang SP Codd EE Colburn RW Stone DR Brandt MR Flores CM Dax SL 《Bioorganic & medicinal chemistry letters》2008,18(8):2730-2734
High throughput screening of our compound library revealed a series of N-pyridyl-3-benzamides as low micromolar agonists of the human TRPV1 receptor. Synthesis of analogs in this series led to the discovery of a series of N-quinolin-3-yl-benzamides as low nanomolar antagonists of human TRPV1. 相似文献
105.
Anti-clotting activity of endothelial cell cultures and heparan sulfate proteoglycans 总被引:4,自引:0,他引:4
A photoaffinity probe for the vitamin D-dependent chick intestinal calcium binding protein (CaBP) has been prepared by conjugation of methyl-4-azidobenzoimidate (MABI) to lactoperoxidase-125I-iodinated CaBP to yield 125I-CaBP-MABI: [3 moles MABI per mole CaBP]. After incubation of 125I-CaBP-MABI (28,000 daltons) in model systems with bovine intestinal alkaline phosphatase (AP) (67,000 daltons), a UV light-dependent crosslinking occurred to yield a conjugate with a molecular weight of 95,000 (by SDS-gel electrophoresis); no crosslinking occurred with alkaline phosphatase. The formation of the 125I-CaBP-MABI-AP was found to occur only in the presence of calcium. 相似文献
106.
Metal chelates in the storage and transport of neurotransmitters: formation of mixed ligand chelates of Mg 2+ -ATP with biogenic amines 总被引:2,自引:0,他引:2
Abstract— Quantitative studies on the interactions of adenosine-triphosphate and several biogenic amines with magnesium ion have been carried out in an attempt to correlate the thermodynamic stabilities of the metal-binding of the amines with the in vivo affinities of the amines for granule-binding. Equilibrium data indicate that in each of the ternary chelate systems (viz. Mg2+-ATP-amine), the predominant reaction in the pH range 3.0–7.0 is the formation of a magnesium-ATP chelate with a stability constant, log KML=3.22 ± 0.02. Each of the biogenic amines coordinates with Mg2+-ATP system in the pH range 7.0–10.5 to form the mixed ligand chelate (or ternary chelate), Mg2+-ATP-amine(1:1:1). The stability constants for the binding of the amines with Mg2+-ATP are: (i) norepinephrine (NE) = 2.34 ± 0.32; (ii) epinephrine (E) = 2.95 ± 0.08; (iii) dopamine (DA) = 3.05 ± 0.06; (iv) octopamine (OA) = 1.93 ± 0.12; (v) 6-hydroxydopamine (6-HDA) = 2.42 ± 0.14; (vi) 3-methoxynorephedrine (MeN) =2.76 ± 0.09; (vii) amphetamine (AA) =2.09 ± 0.05; (viii) tyramine (TA) = 2.60 ± 0.04; (ix) phenylethylamine (PEA) = 0. A general correlation is indicated between the stability constants (binding strengths) of the amine chelates and the metal-binding functionalities of the amines on the one hand and their vesicular binding characteristics in in vivo systems on the other (Carlsson and Waldeck , 1966). The Mg2+-ATP-dependant amine storage mechanism of KIRSHNER (1962a;b) and Carlsson , Hillårp and Waldeck (1963) is discussed both in the light of the data on metal chelate stability and of a significant modification of metal coordination hypothesis. 相似文献
107.
W.A. Colburn 《Steroids》1975,25(1):43-52
A specific, sensitive, precise and accurate radioimmunoassay has been developed for fluoxymesterone, 9α-fluoro-11β, 17β-dihydroxy-17-methyl-4-androsten-3-one (Halotestin®). The method is capable of detecting 25 picograms of drug in 0. 1 ml of unextracted serum. The primary antibody was prepared against fluoxymesterone 3-[0-(carboxymethoxime)] (CMO) bovine serum albumin. The specificity of the assay is greatly influenced by the hydroxyl group at position 11 and the methyl group at position 17. Physiological levels of endogenous steroids did not cross-react significantly with the primary antibody. Blood levels of fluoxymesterone were determined in both human subjects and male beagle dogs after oral administration of Halotestin. 相似文献
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109.
The JB6 mouse epidermal cell model system is being used to study the mechanism of promotion of transformation. Promotion of anchorage independence in JB6 cells occurs in response to second-stage but not first-stage promoters, and is inhibited by inhibitors of second-stage not first-stage promotion. A number of variants that are resistant to the phorbol diester TPA have been derived. Some are resistant to plateau density mitogenic stimulation by TPA; others are resistant to promotion of anchorage independence by TPA. Some of the mitogen-resistant variants were promotable by TPA, thus ruling out a requirement for TPA mitogenesis in promotion of transformation in JB6 cells. TPA promotable clones were also sensitive to mezerein and EGF while the TPA nonpromotable variants were also resistant to mezerein and EGF, suggesting that sensitivity to promoters in these JB6 cells is determined at a level distal to receptor binding. Promotion sensitivity did not require available EGF receptors since two TPA promotable variants were EGF receptorless. The mitogenic response of JB6 cells to TPA may however be mediated by EGF since four of four mitogen-resistant variants showed low to zero levels of EGF binding. Tumor promoting phorbol esters produce specific changes in cellular gangliosides. Certain of these changes occur in promotable but not nonpromotable variants of JB6 cells, suggesting that ganglioside changes may be involved in the process of promotion of transformation. 相似文献
110.
JB6 mouse epidermal cells have been selected for resistance to the tumor-promoting phorbol diester TPA for (1) the plateau density mitogenic (M) response, and (2) the promotion of tumor cell phenotype (P) response. The purpose of this study was to determine the relationship of hexose uptake to the two TPA-dependent processes. Monolayers of JB6 mouse epidermal cells showing one of four different phenotypes (M + P+, M + P?, M? P+, M? P?) were exposed to 60 nM [3H(G)]2 deoxy-D-glucose (2DG) with or without TPA (10 ng/ml) stimulation. The TPA mitogen-sensitive (M + P +/?) cells, when in logarithmic growth, had a lower basal 2DG uptake rate than TPA mitogen-resistant (M? P +/?) cells. At plateau density, however, only the M+P+ cells had a significantly lower basal rate. The M + (TPA mitogen-sensitive) cells (with low basal rates), when preincubated with TPA, exhibited a two to threefold increase in 2DG uptake, while the M? (TPA mitogen-resistant) lines, which already showed elevated rates, remained unchanged. There was also a positive association between TPA mitogen sensitivity and slower growth rate. These results suggest that low hexose sugar uptake is related to TPA mitogen sensitivity, but not to promotion sensitivity. Hence the cell's ability to increase its uptake rate may be required for the cells to respond to mitogenic stimulation by TPA. 相似文献