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91.
蛇毒类凝血酶calobin在毕赤酵母中的表达 总被引:1,自引:0,他引:1
蛇毒类凝血酶是临床上防治血栓栓塞性疾病的有效药物。参照朝鲜蝮蛇(Agkistrodon caliginosus,Korean Viper)类凝血酶calobin基因序列(GenBank AccessionNo.U32937.1),将人工合成的calobin基因克隆到酵母表达载体pPICZαA,于毕赤酵母中表达,得到了分子量约为32kD的重组calobin蛋白,经甲醇诱导培养,表达产物可获得3.5g/L的高表达量。重组蛋白经过阴离子交换柱Q-Sepharose Fast Flow和分子筛Sephacryl-S-100凝胶过滤层析等纯化步骤进行了初步纯化。纯化后的重组calobin可以在纤维蛋白原平板上形成水解圈,经SDS-PAGE实验显示,重组蛋白能水解纤维蛋白原的Aα链,产生一条约40kD左右的降解带。在实验中未能发现重组calobin对纤维蛋白原的凝固作用。 相似文献
92.
钼、硼对大豆叶片膜脂过氧化及体内保护系统的影响 总被引:32,自引:0,他引:32
The study deals with the changes of membrane peroxidation and endogenous protective system with different supplementation of molybdenum (Mo) and/or boron (B) concentration in soybean (Glycine max L.) leaves at three developmental stages (5-trifoliate stage, initiation of flowering, and peak podsetting stage) in three pot-grown soybean varieties (“Zhechun No.3”, “Zhechun No.2”, “3811”). The control plants under low Mo and low B exhibited an increasing of membrane permeability (MP), malondialdehyde (MDA) and proline (Pro) contents, polyphenol oxidase (PPO) and ascorbate oxidase (AO) activities and a decrease of ascorbate (AsA) contents, superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (AP) and catalase (CAT) activities. Application of Mo or B alone raised the ability of anti-oxidant of soybean leaves. The results indicated that the anti-oxidant enzymes (including SOD, POD, CAT and AP) related closely to anti-oxidant compounds (including AsA and Pro). There was some difference between the effects of Mo and B on the anti-oxidant, and a synergetic effect was observed between Mo and B. Some genetic variation in the responses to Mo and B was found among the three soybean varieties which was related to the activities of the total anti-oxidant systems. 相似文献
93.
94.
Zhen‐Yu Li Yu‐Cheng Gu Dianne Irwin Jacqueline Sheridan John Clough Ping Chen Shu‐Ying Peng Yi‐Ming Yang Yue‐Wei Guo 《化学与生物多样性》2009,6(10):1744-1750
Two new Daphniphyllum alkaloids, macropodumines J and K ( 1 and 2 , resp.), together with six known structurally related alkaloids, 3 – 8 , were isolated from the bark of Daphniphyllum macropodum Miq . The structures of the new compounds 1 and 2 were elucidated on the basis of a comprehensive analysis of their spectroscopic and chemical data. Macropodumine J ( 1 ) contains a CN group which is relatively rare in naturally occurring alkaloids. All isolated compounds were tested for their insecticidal activities against a number of insect species. Daphtenidine C ( 5 ) is the most active compound against Plutella xylostella. This is the first report of insecticidal properties of Daphniphyllum alkaloids. 相似文献
95.
Two novel aminooligosaccharides were separated from the culture filtrate of Streptomyces coelicoflavus ZG0656. Their chemical structures were determined by electrospray ionization tandem mass spectrometry (ESI-MS/MS) and 2D nuclear magnetic resonance (NMR) spectroscopy. Because of their acarviosine core structures, the names acarviostatins II23 and II13 were given to the novel compounds. The two acarviostatins were both mixed noncompetitive inhibitors of porcine pancreatic alpha-amylase (PPA), with inhibition constants (K(i)) of 0.009 microM (acarviostatin II23) and 0.010 microM (acarviostatin II13). Therefore, acarviostatin II23 and acarviostatin II13 are, respectively, 231 and 208 times more potent than acarbose. 相似文献
96.
We investigated the effects of homocysteine (Hcy) and oxidized low density lipoprotein (ox-LDL) on DNA methylation in the promoter region of the estrogen receptor α (ERos) gene,and its potentialmechanism in the pathogenesis of atherosclerosis.Cultured smooth muscle cells (SMCs) of humans weretreated by Hcy and ox-LDL with different concentrations for different periods of time.The DNA methylationstatus was assayed by nested methylation-specific polymerase chain reaction,the lipids that accumulated inthe SMCs and foam cell formations were examined with Oil red O staining.The proliferation of SMCs wasassayed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method.The results showedthat ox-LDL in moderate concentrations (10-40 mg/L) induced de novo methylation in the promoter regionof the ERα gene of SMCs.However,high concentrations (50 mg/L) of ox-LDL,resulted in demethylation ofERα.The Hcy treatment resulted in de novo methylation in the promoter region of the ERα gene with aconcentration- and treating time-dependent manner,and a dose-dependent promoting effect on SMCproliferation.These data indicated that the two risk factors for atherosclerosis had the function of inducingde novo methylation in the promoter region of the ERα gene of SMCs. However,high concentrations (50rag/L) of ox-LDL induced demethylation,indicating that different risk factors of atherosclerosis with differentpotency might cause different aberrant methylation patterns in the promoter region of the ERα gene.Theatherogenic mechanism of Hcy might involve the hypermethylation of the ERα gene,leading to the proliferationof SMCs in atherosclerotic lesions. 相似文献
97.
98.
Hsiang-Fei Chen Shih-Huan Peng Kun-Hsien Tsai Cheng-Fen Yang Mei-Chun Chang Yeou-Lin Hsueh Chien-Ling Su Ruo-Yu Wang Pei-Yun Shu Su-Lin Yang 《PLoS neglected tropical diseases》2022,16(4)
Scrub typhus is the most common endemic vector-borne disease in Taiwan. We identified a total of 4,857 laboratory-confirmed cases during 2006–2016 with hyperendemic foci on offshore islands, including Penghu (778 cases, 16.0%) and Kinmen (716 cases, 14.7%), and eastern Taiwan, including Taitung (628 cases, 12.9%) and Hualien (508 cases, 10.5%). Scrub typhus cases occur year-round throughout Taiwan, with a summer peak in June and July. A total of 545 O. tsutsugamushi isolates were successfully obtained from patients infected in diverse geographic areas, including Taiwan and three offshore islands, and the complete open reading frame of the 56 kDa type-specific antigen gene (tsa56) sequence of these isolates was examined. High phylogenetic diversity was found in these isolates, which could be grouped into 36 distinct sequence types. Most isolates belonged to the Karp (49.9%; 272/545), followed by the TW-22 (17.8%; 97/454) and Kawasaki (14.7%; 80/545) genotypes. In conclusion, our data indicate the widespread presence of tsa56 genotypes closely related to Thailand and Korean strains and the presence of the unique endemic strains TW-12, TW-22, TW-29, and TW-36 in Taiwan. 相似文献
99.
Ultravoilet photoelectron spectroscopy has been employed to exmamin the valence electronic structure of 5-fluorouracil, 5-chlorouracil, 5-bromouracil, and 5-iodouracil. Photoelectron bands associted with the three highest π orbitals and the two oxygen atom lone-pair orbitals were assigned by a comparison to similar bands observed in the photoelectron spectrum of uraciul. Bands arising from the halogen atom lone-pair orbitals were assigned by comparing the present results with photoelectron spectra measured for halobenzenes, and by considering the linear dependence of halogen atom lone-pair ionization potentials upon halogen atom electronegativities. The present spectroscopic results have been compared with results from studies of association constants of 5-halouracil–adenine complexes. This examination in dicates that the complex association constants incresase as the ionization potentials of the highest occupied π orbital and the halogen atom lone-pair orbitals of th halouracils decrease. 相似文献
100.
Hai‐Fan Yu Lian‐Wen Zheng Zhan‐Qing Yang Yu‐Si Wang Ji‐Cheng Huang Shu Liu Zhan‐Peng Yue Bin Guo 《Journal of cellular and molecular medicine》2020,24(12):7023-7033
Serpinb6b is a novel member of Serpinb family and found in germ and somatic cells of mouse gonads, but its physiological function in uterine decidualization remains unclear. The present study revealed that abundant Serpinb6b was noted in decidual cells, and advanced the proliferation and differentiation of stromal cells, indicating a creative role of Serpinb6b in uterine decidualization. Further analysis found that Serpinb6b modulated the expression of Mmp2 and Mmp9. Meanwhile, Serpinb6b was identified as a target of Bmp2 regulation in stromal differentiation. Treatment with rBmp2 resulted in an accumulation of intracellular cAMP level whose function in this differentiation program was mediated by Serpinb6b. Addition of PKA inhibitor H89 impeded the Bmp2 induction of Serpinb6b, whereas 8‐Br‐cAMP rescued the defect of Serpinb6b expression elicited by Bmp2 knock‐down. Attenuation of Serpinb6b greatly reduced the induction of constitutive Wnt4 activation on stromal cell differentiation. By contrast, overexpression of Serpinb6b prevented this inhibition of differentiation process by Wnt4 siRNA. Moreover, blockage of Wnt4 abrogated the up‐regulation of cAMP on Serpinb6b. Collectively, Serpinb6b mediates uterine decidualization via Mmp2/9 in response to Bmp2/cAMP/PKA/Wnt4 pathway. 相似文献