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1.
以峰度、偏度和变动系数为指标研究了辽东山区天然次生林直径株数分布特征。运用Johnson’s SB分布、Gamma分布、3参数和2参数Weibull分布等4种概率密度函数研究了辽东山区天然次生林直径株数分布规律,同时利用Kolmogorov-Smirnov(KS)检验法来检验4种概率分布的拟合效果,结果表明:林分直径的株数分布以Johnson’s SB分布拟合效果最好,Weibull分布(包括2参数和3参数)仅仅适合中度区和弱度区,但不是最好。所有的分布模型均通过了优势度检验,说明均适用于直径株数分布的拟合。  相似文献   
2.
Cucumber Fusarium wilt (CFW), caused by the soil-borne fungus Fusarium oxysporum f. sp. cucumerium, is a serious disease in cucumber (Cucumis sativus) production worldwide. For the efficient control of the pathogenic fungi, a better understanding of its interaction and associated resistance mechanisms at the molecular level is required. Here, we report a comparative proteomics analysis of total root protein isolated from infected cucumber root of susceptible bulk (SB) and resistant bulk (RB) of cucumber generation F2. Two-dimensional gel electrophoresis (2-DE) coupled with MS/MS approaches identified 15 over-accumulated proteins from the RB plants. Identified proteins are mainly involved in defense and stress responses, oxidation reduction, metabolism and transport and other process. These proteins are likely to be a part of resistance-related protein network, playing different roles in cucumber disease resistance. Three vital clues regarding wilt resistance of C. sativus are gained from this study. First, jasmonic acid and redox signaling components were found in response to F. oxysporum infection in resistant plants. Second, the LRR family protein may play an important role in the defense reaction against CFW. Third, biotic and abiotic stress-related proteins were induced by the CFW fungus F. oxysporum, indicating the activation of common stress pathway.  相似文献   
3.
AIM:To explore the hypothesis that initiation of pulmonary hypertension involves the up-regulation of monocyte chemoattractant protein-1 (MCP-1) in acute pulmonary thromboembolism (PTE), and to evaluate the role of p38 mitogen-activated protein kinase (MAPK) in this process. METHODS:One hundred and fifty male SD rats were randomly divided into five groups (n=30): normal control group, solvent control group, acute PTE group, acute PTE plus SB203580 (a p38 MAPK specific inhibitor) pretreatment group and acute PTE plus C1142 (a rodent chimeric monoclonal antibody neutralizing rat MCP-1) pretreatment group. Thirty rats in each group were further divided into 1, 4 and 8 h subgroups (n=10). A rat model of acute PTE was established by infusion of an autologous blood clot into the pulmonary artery through a polyethylene catheter. SB203580 or C1142, dissolved in 1% dimethyl sulfoxide (DMSO), was administered to the animals through caudal vein 1 h prior to the beginning of acute PTE modeling. Rats in normal control group and solvent control group were injected with normal saline and 1% DMSO, respectively. The mean pulmonary artery pressure (MPAP) and the mRNA and protein expression of MCP-1 were measured at each time point. RESULTS:Acute PTE elicited significant increase in MPAP, and up-regulated the expression of MCP-1. Pretreatment with SB203580 or C1142 significantly reduced MPAP, and down-regulated the expression of MCP-1. CONCLUSION:These findings suggest that MCP-1 is involved in the formation of acute PTE-induced pulmonary hypertension, and SB203580 down-regulates the expression of MCP-1 via p38 MAPK signaling pathway, thus attenuating pulmonary hypertension.  相似文献   
4.
Feng AW  Yu C  Mao Q  Li N  Li QR  Li JS 《Fitoterapia》2011,82(7):976-982
The effect of berberine hydrochloride (BBR) on inducible cyclooxygenase-2 (COX-2) in small intestinal mucosa and related mechanisms was investigated in a rat model of acute endotoxemia. The results showed that lipopolysaccharide (LPS) increased COX-2 expression, whereas SB202190 and BBR curtailed it. LPS increased phosphorylation of mucosal p38 MAPK and ATF2 as well as production of ATF2, whereas BBR attenuated these effects. LPS upregulated mucosal peroxisome proliferator-activated receptor gamma (PPARγ), but BBR reduced this receptor. GW9662 aggravated LPS-induced and reversed BBR-attenuated COX-2 expression. The findings showed that BBR ameliorated COX-2 overexpression partially via modulation of p38 and PPARγ pathways during acute endotoxemia.  相似文献   
5.
含双边界序列植物双价表达载体的构建   总被引:3,自引:0,他引:3  
转基因植物的安全性是基因工程改良作物的一个重要问题.构建含双边界序列(双T-DNA区)载体,将选择标记基因和目标外源基因分开在不同的T-DNA区,通过转基因植株有性杂交及后代分离,可在转基因后代中获得无选择标记的转基因安全植株.将2个外源基因置于同一载体上,可以提高其共转化的效率.本研究构建了1个中间载体pAHC17-PTA和1个含双边界序列的植物双价表达载体pDB13PS.pAHC17-PTA含有由Ubiquitin启动子引导的具有抗虫效果的半夏凝集素基因(PTA).pDB13PS含2个独立的T-DNA区,在其中一个T-DNA区,含两个目的基因的完整的表达盒,一个是由Ubiquitin启动子引导的半夏凝集素基因(PTA),另一个是由水稻胚乳特异表达启动子(Glutelin-B1 promoter)驱动的马铃薯高赖氨酸蛋白基因的cDNA(SB401).pDB13PS的成功构建,为提高PTA和SB401的共转化效率和获得无选择标记的转基因后代植株奠定了基础.  相似文献   
6.
7.
Outbreaks of a new mating type (A2) of late blight (Phythopthora infestans) and the spread of bacterial wilt (Ralstonia solanacearum) were the most notable events among fungi and bacteria during the last 10 to 15 years in the Andes. The emergence of the A2 mating type of P. infestans was probably a result of seed movement from the Northern hemisphere. Black scurf caused by the fungus Rhizoctonia solani spread in Peru and Bolivia causing economic losses estimated at 5 to 10%. A high incidence of common scab on potato tubers, caused by the bacteria Streptomyces scabies was found in some localities in Bolivia. Among the emerging viruses, the NTN strains of PVY have been found in some countries including Peru. Recently, two other viruses have been found spreading in potatoes. One is coded SB26/29 and is transmitted by Russelliana solanicola, the first psyllid vector found for a plant virus. The other emerging virus is coded SB41 and is apparently also new to potatoes. It causes a severe mosaic on the affected plants and the virus is transmitted experimentally only by grafting. Some other viruses of minor importance have also been detected in potatoes.  相似文献   
8.
郁金香切花在瓶插过程中,自由基清除剂苯甲酸钠(SB)处理可显著减缓蛋白质含量的下降,降低膜脂过氧化产物MDA的积累,维持膜的完整性,减缓膜脂的饱和化趋势,对膜系统有一定保护作用,提高切花观赏品质。而自由基源硫代硫酸钠(Na_2S_2O_3)则加速切花瓶插过程中蛋白质含量的下降,增加MDA含量和膜透性的上升幅度,促使膜脂趋于饱和化,加速切花的衰老。  相似文献   
9.
全球定位系统(GPS)是当代发展非常迅速的信息技术系统,运用领域也由最初的高端军事领域深入到日常的生产生活中。运用GPS技术进行草原调查,是草原调查数字化、信息化的趋势。本研究介绍了Trimble Juno SB手持机在草原调查中各阶段的应用,系统地总结归纳了手持GPS在草原调查与制图中的应用技术和方法,为应用GPS技术开展草原资源调查与制图工作提供参考。  相似文献   
10.
超级杂交水稻的培育、推广和应用可显著提高水稻的单位面积产量,但许多超级杂交水稻存在抗虫能力较低、品质较差的问题。1826是一个优良的超级杂交水稻亲本材料,但抗褐飞虱能力低,必需氨基酸赖氨酸的含量低。本研究利用基因工程技术将CaMV 35S启动子引导的半夏凝集素基因(PTA)和水稻胚乳特异表达启动子(Glutelin-B1 promoter)引导的马铃薯高赖氨酸蛋白基因(SB401)同时转入1826成熟胚诱导的愈伤组织中,获得了同时含PTA和SB401的转基因植株。本研究为提高1826的抗褐飞虱能力和赖氨酸含量打下了基础。  相似文献   
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