共查询到20条相似文献,搜索用时 23 毫秒
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潘庆民1,于振文2,王月福2 总被引:5,自引:0,他引:5
采用盆栽和水泥池栽研究了追氮时期对小麦光合作用、14C同化物运转分配和硝酸还原酶(NR)活性的影响.结果表明,拔节(雌雄蕊原基形成)期较起身(二棱)期追施氮肥,显著提高了小麦开花后的旗叶叶绿素含量和单叶光合速率;灌浆期旗叶14C同化物向籽粒转移比例显著提高,而在营养器官的滞留比例显著降低;旗叶和根系中硝酸还原酶(NR)活性亦显著提高.小麦穗粒数、粒重和产量增加,蛋白质含量提高. 相似文献
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Fátima M.F. Vergara Maria das G.M.O. Henriques André L.P. Candea Jim L. Wardell Marcus V.N. De Souza 《Bioorganic & medicinal chemistry letters》2009,19(17):4937-4938
A series of 11 α,ω-diaminoalkanes, (H2N(CH2)nNH2, n = 2–12) have been evaluated for their in vitro antibacterial activity against Mycobacterium tuberculosis H37Rv. Compounds, (H2N(CH2)nNH2, n = 9–12), exhibited a very good activities in the range 2.50–3.12 μg/mL, which can be compared with that of the first line drug, ethambutol (3.12 μg/mL). These results and a preliminary QSAR study can be considered an important start point for the rational design of new leads for anti-TB compounds. 相似文献
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N. A. M. Wales 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1988,158(5):621-626
Summary Hagfish,Myxine glutinosa, were used in an investigation of the possible effects of various eicosanoids and the prostaglandin synthetase inhibitor indomethacin, on cortisol production, blood pressure control, urine flow and electrolyte balance.Cortisol levels in plasma of untreated control animals and plasma from animals 1 h following injection of 50 g kg–1 prostaglandin E1, E2, A2, F2 TXB2 and indomethacin were not detectable. However, plasma cortisol levels rose to between 10 and 26 pg ml–1 1 h following injection of either 50 g kg–1 arachidonic acid or prostaglandin E2. This rise was similar in magnitude to that produced 1 h following administration of 50 g kg–1 porcine ACTH.The resting dorsal aortic blood pressure of between 3.50 and 3.75 mmHg was reduced on average by 50% for 12–15 min when animals received 10 g kg–1 arachidonic acid, prostaglandin E1, E2, A2, and TXB2 and was effectively reduced to zero for 20 min or more following 50 g kg–1 of these eicosanoids. Similar doses of prostaglandin F2, however, evoked an increase in blood pressure (19–33%) whilst indomethacin was without effect.Control measurements of urine flow inMyxine were estimated to be between 540 and 660 l h–1 kg–1. There was a marked reduction in urine output following the arterial vasodepression induced by arachidonic acid, prostaglandin E1, E2, A2 and TXB2 in doses of 10 g kg–1, an effect which became even more pronouced following injection of 50 g kg–1 quantities, leading in some cases to complete anuria. There was no significant change in urine volume following either the vasopressor action of prostaglandin F2 or following indomethacin.None of the compounds tested in this study significantly influenced the plasma or urine electrolyte status ofMyxine. 相似文献
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质量—数量性状遗传参数估计的P1,P2,F1,B1,B2联合分析方法 总被引:2,自引:1,他引:1
提出利用亲本P_1和P_2、杂种F_1、回交B_1和B_1五个世代联合分析包括两个位点主基因控制的质量-数量性状遗传的统计方法,共建立了可供选择的微基因遗传、一对主基因+微基因混合遗传、二对主基因+微基因混合遗传三类五种(套)共 28个遗传模型,采用 AIC信息准则选择最适模型,并通过适合性检验对所选择的遗传模型做进一步的检验.文章最后还讨论了两种变型设计. 相似文献
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石贵贤 《中国生物工程杂志》1987,7(4):69-70
在讨论Takeda化学公司的“克服某些重组蛋白生产中的困难的努力”时,YukioSugino叙述了大肠杆菌合成的白细胞间介素—2(IL—2)的首次结晶。这大坂Takeda生物工程公司实验室主任、《生物/技术》科学顾问委员会成员Sugino是在一月底本刊召开的“《生物/技术》展望下个十年”讨论会上讲的,约有350名科研工作者和作者和科研管理人员参加了这次秘密会议。 相似文献
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Alan Paine 《Biomarkers》2013,18(3):203-205
As part of a programme to develop biomarker assays for polycyclic aromatic hydrocarbons (PAHs) in marine invertebrates, two species of crabs, Carcinus maenas and Carcinus aestuarii were exposed to benzo(a)pyrene (B(a)P) or crude oil. Microsomes were prepared from the midgut gland (hepatopancreas), examined by gel electrophoresis and Western blotting and assayed for B(a)P monooxygenase activity. In early experiments there was evidence of protein degradation and results were inconsistent and inconclusive. However, when steps were taken to minimize this in subsequent experiments, including the inclusion of four protease inhibitors in the homogenization buffer, there was consistent evidence for an increase of proteins of estimated molecular weight 45-60 kDa, and particularly of a distinct band at c. 48 kDa, following exposure to PAH at levels down to 0.1 ppm in ambient water. In C. aestuarii the increase in this band was found to coincide with an 8-12-fold increaseof B(a)P monooxygenase activity in midgut gland microsomes. These results suggest that one or more forms of cytochrome P450 may be induced by PAHs in these species. However, Western blotting using antibodies raised to vertebrate P450s, and representing four different gene families, failed to recognize any proteins in either the PAH-treated samples or in the controls. The isolation and characterization of induced protein, and the production of antibodies may provide the basis for a biomarker assay to measure a response to environmental PAHs in crabs. 相似文献
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G. A. Freeman D. W. Selleseth J. L. Rideout R. J. Harvey 《Nucleosides, nucleotides & nucleic acids》2013,32(1-2):155-174
Abstract 2,5,6-Trihalogenated benzimidazole-β-D-ribofuranosyl nucleosides and 2-substituted amino-5,6-dichlorobenzimidazole-β-L-ribofuranosyl nucleosides are potent and selective inhibitors of human cytomegalovirus (HCMV). The D-ribofuranosyl analogs are metabolized rapidly in vivo rendering them unsuitable as drug candidates. The primary source of instability is thought to be the anomeric bond. The synthesis of a series of chemically stable benzimidazole-2′-isonucleosides is presented. The synthetic schemes employed are based on nucleophilic displacements of a 2′-tosylate from carbohydrate intermediates with 2-bromo-5,6-dichlorobenzidazole. 2-Bromo and 2-isopropyl amino analogs with 3′- and 5′-oxo and deoxy substitutions were prepared. The benzimidazole-2′-isonucleosides presented here demonstrated reduced activity against HCMV when compared to other D-ribofuranosyl benzimidazole analogs. In addition, they were not found to be inhibitors of HIV. 相似文献
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Increasing evidence suggests that chronic, sub-clinical inflammation plays an important role in the pathogenesis of diabetic retinopathy. We have established the potential role of the inflammatory enzyme, core 2 β-1, 6-N-acetylglucosaminyltransferase (C2GNT) in diabetic retinopathy. The present study was designed to explore the NADPH oxidase signaling pathway in the tumor necrosis factor-alpha (TNF-α)-induced activity of C2GNT in leukocytes. Human leukocytes (U937 cells) and an Epstein-Barr-transformed lymphoblastoid cell line deficient in p47phox (F10007 cells) were used for the study. Cells were exposed to TNF-α for 24 h in the presence and absence of 1) NADPH oxidase inhibitors (apocynin and scrambled and unscrambled gp91ds-tat), 2) LY379196 (specific protein kinase C β1/2 (PKCβ1/2) inhibitor), and 3) the antioxidant tiron. Subsequent C2GNT and NADPH activity was measured and the adhesion of U937 and F10007 cells to endothelial cells was assessed. TNF-α-induced C2GNT activity (1813 ± 326 pmol/h/mg protein) (mean ± SEM) in human leukocytes was significantly reversed with apocynin (153 ± 82 pmol/h/mg protein), unscrambled gp91ds-tat (244 ± 122 pmol/h/mg protein) and tiron (756 ± 87 pmol/h/mg protein). We further supported this C2GNT-NADPH oxidase link using p47phox-deficient leukocytes. The deficiency in p47phox prevented TNF-α-induced NADPH oxidase and C2GNT activity and adherence to endothelial cells. The response to TNF-α was restored by transfection with an expression plasmid containing a p47phox cDNA inserted in the sense direction. Our results demonstrate for the first time a novel signaling crosstalk between TNF-α, NADPH oxidase, PKCβ1/2 and C2GNT in leukocytes. 相似文献
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Cyclooxygenase-2 (COX-2) activity has been implicated in the pathogenesis of cerebral ischemia. To determine whether COX-2
activity within the neuron itself exacerbates hypoxic neuronal injury, neuron-enriched cultures were subjected to anoxia.
Treatment with COX-2 selective antagonists decreased cell death. Neurons cultured from homozygous COX-2 gene disrupted mice
were resistant to hypoxia compared to those of heterozygotes. Infection of primary neurons with AAV expressing COX-2 exacerbated
cell death compared to neurons infected with enhanced green fluorescent protein (EGFP) control vector. Addition of PGE2, PGD2
or PGF2α to the medium exacerbated injury, suggesting that the deleterious effects of COX-2 overexpression in hypoxia could
be mediated by direct receptor mediated effects of prostaglandins. Overexpression of COX-2 did not increase expression of
cyclin D1 or phosphoretinoblastoma protein (pRb), or cleavage of caspase 3 suggesting that this cell cycle mechanism does
not mediate COX-2 toxicity in this model. 相似文献
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Zusammenfassung Aus kultivierten Lungenfibroblasten eines nach 7 Wochen verstorbenen Säuglings mit den klinischen Zeichen eines Morbus Down konnte ein Chromosomenmosaik diploider und tetraploider Zellen im Verhältnis 2:1 mit zusätzlicher G/D-Translokationstrisomie diagnostiziert werden.Auf Grund morphologischer, cytogenetischer und cytologischer Befunde wird angenommen, daß die tetraploiden Zellen ihren Ursprung vom Ausgangsgewebe, den Explantaten aus der Lunge, genommen haben.
Chromosome mosaic 46,XY,D-,t(DqGq)+/92,XYXY,2D-,2t(DqGq)+ in fibroblasts of the lung of a baby with Down's syndrome
Summary In a patient with the features common in the Down's syndrome who died after 7 weeks, a chromosome (ploidy) mosaic of diploid and tetraploid cells in a relation of 2:1 and with additional G/D translocation trisomy was present in cultivated fibroblast cells of the lung.From the data of morphological, cytogenetical and cytological investigations it is concluded, that the tetraploid cells originated from the explantates of the lung.相似文献
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Abstract A convenient, high-yield synthesis of 1,3,5-tri-O-acetyl-2-deoxy-α. β-D-erythro-pentofuranose from 2-deoxy-D-erythro-pentose is described. 相似文献
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《Biochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism》1994,1210(2):244-248
F2-isoprostanes are prostaglandin (PG)F2-like compounds that are produced in vivo as non-enzymatic products of free radical catalyzed peroxidation of arachidonic acid. One F2-isoprostane whose formation should be favored is 8-epi-PGF2α. 8-Epi-PGF2α has been shown to exert potent bioactivity but proof that it is formed in vivo is lacking. Evidence is now presented suggesting that 8-epi-PGF2α is, in fact, formed in vivo by demonstrating that an endogenous F2-isoprostane with a retention time on capillary GC identical with that of 8-epi-PGF2α co-chromatographs through four high resolving HPLC purification procedures with authentic radiolabelled 8-epi-PGF2α. 相似文献
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