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31.
Mu-jin Tang Shao-ling Zeng Jian-wu Chen Yong-xia Shi Wei Xu Mei-jin Yuan Yi Pang 《Insect Science》2003,10(4):221-229
A series of plasmids were constructed to examine the effects of p19 and orf1‐orf2 genes from Bacillus thuringiensis on Cyt1Aa synthesis and inclusion formation. The plasmids expressed the cyt1Aa gene along with either p19 or orf1‐orf2, or each of them coordinatively with p20 in the acrystalliferous strain of B. thuringiensis subsp. israelensis 4Q7. No effect on the expression of Cyt1Aa protein was found when P19 or Orf1‐Orf2 co‐expressed with Cyt1Aa. However, when including p20 gene, the constructs with p19 or orf1‐orf2 gene produced lower yield of Cyt1Aa proteins than without p19 or orf1‐orf2 gene. Electron microscopy observation and bioassay showed that P19 and Orf1‐Orf2 have no influence on the crystal size and toxicity of Cyt1Aa protein. It is presumed that P19 and Orf1‐Orf2 might have negative effects on Cyt1Aa synthesis in B. thuringiensis. 相似文献
32.
A 250-kilodalton cellular protein is induced by progestins in two human breast cancer cell lines MCF7 and T47D 总被引:1,自引:0,他引:1
We have studied the effect of R5020, a synthetic progestin, on the biosynthesis of cellular proteins extracted from the MCF7 and T47D human breast cancer cells, using gel electrophoresis. R5020 stimulates the synthesis, as measured after [35S]-methionine labelling, and the accumulation, as shown by silver staining, of a protein of molecular weight approximately equal to 250,000. The increase of the labelled 250-kilodalton protein was rapid (3 hours) and after 3 days this protein represented approximately equal to 6% of the total cellular proteins (approximately equal to 1 microgram/150,000 cells). The induction of the 250-kilodalton protein was obtained by physiologically active concentrations of several progestins and high concentrations of 5 alpha-dihydrotestosterone but not by estradiol or dexamethasone. It was inhibited by R486 , a progestin antagonist, but not by flutamide, an androgen antagonist. These results indicate a mediation by the progesterone receptor. The 250-kilodalton protein appears to be an excellent probe to study in cell culture the mechanism of action of progestin on human cells. 相似文献
33.
The ability of several metals to inhibit dopamine beta-monooxygenase was measured and compared with their ability to compete with the binding of 64Cu to the water-soluble form of the bovine adrenal enzyme at pH 6.0. In the presence of an optimal concentration of copper (0.5 microM in the present assay system), an inhibition was observed upon addition of Hg(II), Zn(II), or Ni(II). Only a small fraction of the inhibition with these metals may be due to uncoupling of electron transport from hydroxylation. Preincubation of these metals with the Cu-depleted apoenzyme before addition of copper, revealed a stronger inhibition than if copper was added before the other metals. Hg(II), Zn(II), and Ni(II) also compete with the binding of 64Cu(II) to the protein. Hg(II) was the most effective and Ni(II) the least effective of these metals, both with respect to inhibition of the enzyme activity and to prevent the binding of 64Cu(II). Competition experiments on the binding of Zn(II) and 64Cu in the presence and absence of ascorbate, indicated i) a similar affinity of Cu(I) and Cu(II) to the native enzyme, and ii) a more rapid binding of Cu(I) than Cu(II) to the Cu-depleted and Zn-containing enzyme. Al(III), Fe(II), Mg(II), Mn(II), Co(II), Cd(II), and Pb(II) neither inhibited the enzyme activity nor competed with the binding of 64Cu(II) to the protein (Fe(II) was not tested for binding). Of those metals cited above only Cu(II)/Cu(I) was able to reactivate the apoenzyme. 相似文献
34.
The sterol diol fraction from the lipids of organ-pipe cactus, Stenocereus thurberi, was separated into five compounds: macdougallin, peniocerol, cyclostenol, stenocereol and thurberol. The last three compounds have not been described before. All compounds were characterized by physical and spectroscopic properties. 相似文献
35.
36.
A high level of binding of [3H]methyltrienolone (R1881 = 17beta-hydroxy-17alpha-methyl-estra-4, 9, 11-trien-3-one) was found in cytosol prepared from adrenals of castrated male rats. Binding of [3H]R1881 was of high affinity (DK = 6.2 nM) and highly specific for androgens. The [3H]R1881 complex migrates at 7-9S on sucrose gradients in low ionic strength buffer and at 4-5S in buffer containing 0.4M KC1. All binding studies have been performed in parallel with rat ventral prostate and adrenal cytosol. The present data suggest the presence of an androgen binding component in rat adrenal tissue. 相似文献
37.
Under the protection of ascorbic acid a 2-hydroxyestrone bovine serum albumin conjugate was prepared containing intact 2-hydroxyestrone as determined by gas chromatographymass spectrometry. Using this antigen highly specific antibodies were raised in rabbits. Cross-reactivity for 2-hydroxyestradiol and 2-hydroxyestriol was 26 and 4.5%, respectively. An assay procedure of 2-hydroxyestrone in human plasma is described. Using special precautions the assay allows the determination of 2-hydroxyestrone in plasma samples of women (50–95 pg/ml), pregnant women (105–220 pg/ml), men (45–65 pg/ml) and children (20–40 pg/ml). 相似文献
38.
A competitive enzyme-linked immunoassay (CELIA) for human serum angiotensin-1-converting enzyme (ACE) was developed. The sensitivity was amplified by using a secondary antibody and an avidin biotin-conjugated horseradish peroxidase complex as the enzyme-labeled reagent. This configuration was compared to three other configurations for an indirect CELIA, and was found to be the most sensitive. A sensitivity of 39 ng/ml ACE was achieved with intraassay and interassay coefficients of variation of 6.3 and 8%, respectively. CELIA will detect ACE in human serum without interference from either pharmacological or endogenous ACE inhibitors. In normal human volunteers, ACE values obtained using CELIA correlated well with values obtained by enzymatic assay. 相似文献
39.
Michio Ohba Keiko Ono Keio Aizawa Setsuo Iwanami 《Journal of invertebrate pathology》1981,38(2):184-190
Bacteriological and serological characteristics of three Bacillus thuringiensis isolates obtained in Japan were investigated. They formed typical rhomboidal parasporal inclusions but flagellar (H) antigens of these isolates were different from those of the known 17 H serotypes of B. thuringiensis. The three isolates were divided into two new serotypes (serotypes 18 and 19). The serotype 18 isolate (3–71) produced thermostable exotoxin and the inclusions of this isolate were toxic to larvae of the silkworm, Bombyx mori, but nontoxic to larvae of the mosquito, Aedes aegypti. The other isolate (119-72) belonging to serotype 18 produced inclusions nontoxic to larvae of B. mori and A. aegypti and did not produce thermostable exotoxin. However, other bacteriological properties of the isolate 119-72 were similar to those of the isolate 3–71. The serotype 19 isolate (117-72) produced inclusions nontoxic to larvae of B. mori and A. aegypti and did not produce thermostable exotoxin. Acid production from saccharose and the production of brownish purple pigment were observed in the two serotype 18 isolates, while neither of them was observed in the serotype 19 isolate. In other 29 biochemical properties tested, there was no difference among the three isolates. Based on these characteristics, the following two subspecies names are proposed: Bacillus thuringiensis subsp. kumamotoensis (serotype 18) for the type strain 3–71 and Bacillus thuringiensis subsp. tochigiensis (serotype 19) for the type strain 117-72. 相似文献
40.
Twenty-seven mainly terpenoid constituents were identified in the essential oil of Mikania micrantha whole plant. Higher terpenoids present in the same plant included two kaurene derivatives and taraxasterol. 相似文献