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991.
利用高效液相色谱法测定奶牛血清中维生素A和维生素E的含量,并探讨其与牛乳中体细胞数的相关性.结果表明:奶牛血清中维生素A的加标回收率为93.8%~106.4%,维生素E的加标回收率为91.5%~105.3%,RSD分别为4.7%和4.4%,该方法简单快速准确可靠,可用于奶牛血清样品中维生素A和维生素E含量的测定.维生素E浓度在泌乳第4~8周与体细胞数呈弱负相关性(R=-0.25,P=0.037),在泌乳第10~14周为中等程度负相关(R=-0.41,P=0.037);维生素A与体细胞数不存在相关性.  相似文献   
992.
993.
以抗除草剂核单基因隐性不育系Yu98-8A1不育株为母本,转Bt基因抗虫棉中棉所41为父本,通过连续回交,选育出双抗(抗虫和抗除草剂)棉花核不育系Yu98-8A2.花冠、花药表型及花粉发育显微观察表明,新型不育系保持了原不育系转育受体Yu98-8A1的败育特性.棉铃虫抗性及草甘膦抗性试验暗示,Yu98-8A2既保持了原不育系Yu98-8A1的除草剂抗性,又聚合了棉铃虫抗性;PCR分子鉴定表明,Yu98-8A2聚合了Bt及EPSPS-G6基因.  相似文献   
994.
AIM: To investigate the effect of Eph receptor A2 (EphA2) on drug resistance of colorectal carcinoma cells and its possible mechanisms. METHODS: Real-time PCR and Western blot were used to detect the expression of EphA2 at mRNA and protein levels in LoVo and LoVo/5-FU cells. EphA2 siRNA was transfected to down-regulate the EphA2 expression in LoVo/5-FU cells, and the drug sensitivity was calculated by CCK-8 assay. Meanwhile, cell migration and invasion were measured by wound healing assay and Transwell assay, and the protein levels of E-cadherin, β-catenin, N-cadherin, vimentin, Notch and Snail were determined by Western blot. RESULTS: The expression of EphA2 at both mRNA and protein levels was significantly up-regulated in LoVo/5-FU cells (P<0.05). Knockdown of EphA2 suppressed the cell viability, and migration and invasion abilities, but promoted drug sensitivity of LoVo/5-FU cells. Up-regulation of E-cadherin and β-catenin, and down-regulation of N-cadherin and vimentin were observed, indicating that the epithelial-mesenchymal transition (EMT) process was suppressed. Knockdown of EphA2 decreased the expression levels of Notch and Snail. CONCLUSION: Down-regulation of EphA2 partly reverses drug resistance of LoVo/5-FU cells. The mechanism may be related to suppressing cell growth, migration, invasion and EMT process via Notch/Snail signaling pathway.  相似文献   
995.
996.
水稻不育系嘉浙91A农艺性状杂种优势分析及利用(英文)   总被引:3,自引:0,他引:3  
通过对嘉浙91A所配的3个新组合嘉浙91A/C10、嘉浙91A/07-2126、嘉浙91A/浙恢7954进行品比试验,分析了嘉浙该3个组合F1代农艺性状中亲优势、超亲优势、竞争优势及平均显性度。结果表明,嘉浙91A配制的3个大区组合F1代穗形较大,每丛穗数多于亲本,生育期较汕优63略有缩短,每穗颖花数、结实率和产量均高于对照汕优63,产量较汕优63增产2.7%~12.1%。3个大区组合F1代的平均杂种优势大小顺序为株高每丛穗数千粒重,嘉浙91A/浙恢7954组合各性状优势较明显,为该试验中的优良组合。嘉浙91A不育性稳定,并且具有较强的恢复性,在生产中利用前景广泛。  相似文献   
997.
以五味子叶片和茎段作为外植体进行愈伤组织的诱导,对愈伤组织诱导的影响因素、愈伤组织发育特征以及愈伤组织形成过程中五味子醇甲的积累情况进行研究.结果表明:B5培养基比MS培养基更利于愈伤组织的诱导.根据愈伤组织的发育状态特征可以将其分为4类,其中颜色微黄、质地疏松的C类愈伤组织中所积累的五味子醇甲含量最高.添加1.0 mg/L BA、0.2 mg/L NAA和0.1 mg/L KT的B5培养基上较易诱导出C类愈伤组织,其五味子醇甲含量最高达到4.28 mg/g FW.该研究的初步结果对通过愈伤组织悬浮培养生产五味子素的进一步研究奠定了重要基础.  相似文献   
998.
Ethiopian mustard (Brassica carinata A. Braun) is an oil‐seed species that has recently become an object of great interest as a promising crop for energy purposes (biodiesel and biolubricant production). In semi‐arid regions of South Italy, soil moisture at sowing time is often inadequate, delaying and reducing seed germination. In this study, the effect of reduced water potential on seed germination in three cultivars of B. carinata (ISCI 7, CT 180 and Sincron) was investigated in the laboratory. Germination behaviour at constant temperatures under low water availability was also analysed through the hydrotime model. Six water potentials (ψs) in PEG solution (0, ?0.2, ?0.4, ?0.6, ?0.8 and ?1.0 MPa) and three temperatures (10, 20 and 30 °C) were used for the germination tests. A thermo‐inhibiting effect was observed at the highest levels of water stress. The hydrotime analysis revealed that the increase of temperature to 30 °C reduced predicted hydrotime (θH) by hastening the rate of germination, but shifted median base water potential (ψb(50)) to higher values (less negative), whereas the lowering of temperature increased θH. These observations may have a great agronomic impact because although fewer seeds germinated at 30 °C at the highest levels of water stress, they may germinate faster in rapidly drying soil. However, genetic differences were observed among cultivars in terms of estimated θH and ψb(50). The hydrotime modelling approach offered in this study may help predict B. carinata seed germination under soil water deficit conditions occurring under early or late autumnal sowing.  相似文献   
999.
基于MK7A11单片机的射频遥控控制器的设计   总被引:1,自引:0,他引:1  
邵锋  张伟 《湖南农机》2010,37(1):8-10
针对当前国内灯具等用电设备落后的控制现状,自行开发设计一款结构简单、低功耗、高抗干扰性、低成本的射频遥控开关控制系统,实现了多路灯具设备的智能无线遥控开关控制.  相似文献   
1000.
Abstract

Studies were carried out on the growth of mould and the production of mycotoxins in grain during drying and storage. Various amounts of forced ambient air, 800, 600, 400, 200 and 0 m3 (air)/(hour ton), were used to dry wheat, which contained 32% moisture at harvest. Samples for mycological examination and determination of mycotoxins and moisture content were taken weekly. At harvest the mould flora consisted of various field fungi with less than 10% Fusarium spp. An increasing proportion of Aspergillius and Penicillium spp. were recorded in the bins at 0 and 200 m3 (air)/h t. The mycotoxin analysis indicated that the Fusarium spp. were also metabolically active until at least five weeks after the grain was put into the store room. The concentration of deoxynivalenol (DON) reached about 10 mg/kg after three weeks in the bins with no air flow, and about 2 mg/kg in the bins at 200 m3 (air)/h t. The zearalenone concentration also increased considerably, to about 5 mg/kg, in the bins with no air flow. The present results show that drying of grains using forced ambient air may produce good conditions for growth of field fungi as well as storage fungi if the flow of air is too low.  相似文献   
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