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201.
202.
以克鲁兹王莲ב朗伍德王莲自交后代’的58个后代为材料,观察分析了叶片卷边颜色、花蕾形状、萼片颜色、萼片着刺数、第1晚和第2晚花色等10个主要性状的分离情况,并对个体性状分离类型进行了聚类。结果表明,其后代性状分离极为广泛,主要表现为负向中亲优势、正向中亲优势和超亲优势。第1晚内瓣色、拟雄蕊尖色、第2晚内瓣色、第2晚外瓣色及第2晚内外瓣色差5个性状之间有高度或显著相关性,其余相关性较低;卷边色、蕾形、萼片颜色、着刺数及第1晚外瓣色5个性状独立遗传的可能性大。个体性状分离类型丰富,主要可分为7大类,绿叶粉花白芯型、红叶玫红花白芯型、绿叶玫红花深玫红芯型、红叶玫红花深玫红芯型、绿叶深玫红花白芯型、红叶粉花深玫红芯型、绿叶萼多刺玫红花白芯型。  相似文献   
203.
Significant increases in remotely sensed vegetation indices in the northern latitudes since the 1980s have been detected and attributed at annual and growing season scales. However, we presently lack a systematic understanding of how vegetation responds to asymmetric seasonal environmental changes. In this study, we first investigated trends in the seasonal mean leaf area index (LAI) at northern latitudes (north of 30°N) between 1982 and 2009 using three remotely sensed long‐term LAI data sets. The most significant LAI increases occurred in summer (0.009 m2 m?2 year?1, p < .01), followed by autumn (0.005 m2 m?2 year?1, p < .01) and spring (0.003 m2 m?2 year?1, p < .01). We then quantified the contribution of elevating atmospheric CO2 concentration (eCO2), climate change, nitrogen deposition, and land cover change to seasonal LAI increases based on factorial simulations from 10 state‐of‐the‐art ecosystem models. Unlike previous studies that used multimodel ensemble mean (MME), we used the Bayesian model averaging (BMA) to optimize the integration of model ensemble. The optimally integrated ensemble LAI changes are significantly closer to the observed seasonal LAI changes than the traditional MME results. The BMA factorial simulations suggest that eCO2 provides the greatest contribution to increasing LAI trends in all seasons (0.003–0.007 m2 m?2 year?1), and is the main factor driving asymmetric seasonal LAI trends. Climate change controls the spatial pattern of seasonal LAI trends and dominates the increase in seasonal LAI in the northern high latitudes. The effects of nitrogen deposition and land use change are relatively small in all seasons (around 0.0002 m2 m?2 year?1 and 0.0001–0.001 m2 m?2 year?1, respectively). Our analysis of the seasonal LAI responses to the interactions between seasonal changes in environmental factors offers a new perspective on the response of global vegetation to environmental changes.  相似文献   
204.
目的:探讨血管内皮生长因子165(VEGF165)对人脐带静脉内皮细胞(HLNECs)内游离镁离子浓度([Mg^2+]i)的调节机制.方法:采用荧光指示剂mag-fura-2及运用PTi阳离子测定系统动态检测HUVECs的[Mg^2+].结果:经酪氨酸激酶阻断剂(tryrphostin A23和genistein),磷脂酰3激酶阻断剂(wortmannin和LY294002),磷脂酶Cγ阻断剂(U73122)预处理,均显著阻断VEGF165诱导的[Mg^2+]i增加.但经磷脂酶C阻断剂无活性的类似物(U73343)和增殖激活蛋白激酶阻断剂(SB202190和PD9S059)预处理,不能阻断VEGF165诱导的[Mg^2+]i增加:结论:VEGF165通过酪氨酸激酶/磷脂酰3激酶/磷脂酶口信号转导途径使细胞内的Mg^2+库释和Mg^2+,从而增加HUVECs的[Mg^2+]i.  相似文献   
205.
大鼠原生殖细胞培养和分化的研究   总被引:2,自引:0,他引:2  
研究大鼠胚胎原生殖细胞(primordial germ cells,PGCs)的培养及分化,取受精后11-12.5天大鼠PGCs进行原代培养,光、电镜观察PGCs及其分化细胞的微细结构,碱性磷酸酶染色检测细胞的分化程度,结果显然显示大鼠PGCs大而圆,散在分布,或多个聚集成团,胞质中含有椭圆形的线粒体和丰富的核糖体,在鼠胚成纤维细胞饲养层存在的情况下,PGCs保持未分化状态,碱性磷酸酶反应呈强阳性,在缺乏饲养层的条件下PGCs很快分化,形态不规则,有伪足,碱性磷酸酶反应减弱,进一步分化可形成具有细长突起的神经元样细胞,胞质中含有细丝束的表皮细胞,可见节律性跳动的心肌细胞,具有分泌颗粒的分泌细胞及似血管,心脏形状的管腔结构等,由PGCs分化来的细胞碱性磷酸酶反应均呈阴性,结果表明大鼠PGCs能够分化形成三个胚层的衍生物,生殖嵴来源的PGCsp是一种具有发育全能性的胚胎多能干细胞,本研究同时证明鼠胚饲养层能抑制大鼠PGCs的分化。  相似文献   
206.
Constructing functional materials on a 3D host is an efficient strategy to tackle issues of lithium (Li) metal anodes. Although non-Li-alloying materials provide structural stability during cycling due to reduced lattice distortions, low lithiophilicity and sluggish mass transport kinetics limit their functionality. Herein, a synergistic strategy is proposed to improve intrinsic lithiophilicity and mass transport kinetics of non-Li-alloying nucleation sites and demonstrate its remarkable efficacy. Two carbon fiber (CF) hosts coated by non-Li-alloying nanosheets with and without oxygen-enriched carbon filler (OCF) as lithiophilicity and mass transport booster (OCF-DSC@CF and DSC@CF, respectively) are constructed and their physiochemical properties are systematically evaluated to reveal the efficacy of OCF. By advanced characterization techniques, including 3D tomography and location-dependent electron energy loss spectroscopies, the complex heterostructure of OCF-DSC@CF with distinctive roles of each constituent is clearly identified. As verified by theoretical and electrochemical analyses, the incorporation of OCF endows OCF-DSC@CF with substantially improved lithiophilicity and mass transport kinetics. Moreover, OCF-DSC@CF induces a multifunctional SEI enriched with LiF and LiCx, which exhibits well-balanced electrical resistivity and ionic conductivity. Benefiting from these attributes, OCF-DSC@CF exhibits an unprecedented cyclability under a low N/P ratio of 1.8, achieving 700 cycles at 0.5C with an exceptional capacity retention of 97.8%.  相似文献   
207.
Complement 5a (C5a), a potent immune mediator generated by complement activation, promotes tumor growth; however, its role in tumor metastasis remains unclear. We demonstrate that C5a contributes to tumor metastases by modulating tumor inflammation in hepatic metastases of colon cancer. Colon cancer cell lines generate C5a under serum-free conditions, and C5a levels increase over time in a murine syngeneic colon cancer hepatic metastasis model. Furthermore, in the absence of C5a receptor or upon pharmacological inhibition of C5a production with an anti-C5 monoclonal antibody, tumor metastasis is severely impaired. A lack of C5a receptor in colon cancer metastatic foci reduces the infiltration of macrophages, neutrophils, and dendritic cells, and the role for C5a receptor on these cells were further verified by bone marrow transplantation experiments. Moreover, C5a signaling increases the expression of the chemokine monocyte chemoattractant protein-1 and the anti-inflammatory molecules arginase-1, interleukin 10, and transforming growth factor β, but is inversely correlated with the expression of pro-inflammatory molecules, which suggests a mechanism for the role of C5a in the inflammatory microenvironment required for tumor metastasis. Our results indicate a new and potentially promising therapeutic application of complement C5a inhibitor for the treatment of malignant tumors.  相似文献   
208.
Fructus Amomi Cardamomi (FA) is the mature fruit of Amomum villosum Lour (family Zingiberaceae) and is commonly used in Chinese traditional medicine to treat various gastrointestinal disorders. FA’s possible benefits as an allergic rhinitis (AR) treatment, however, have not been examined. We used an ovalbumin (OVA)-induced AR mouse model to identify any anti-allergic effects associated with the administration of 200 mg/kg FA or dexamethasone (Dex) 2.5 mg/kg by oral administration. The results of our testing confirm that FA ameliorated nasal symptoms and alleviated nasal epithelium swelling, reduced the goblet cell hyperplasia and eosinophil cell infiltration in the nasal epithelium, and inhibited lung tissue inflammation and Dex as well. Significantly decreased Th2 cytokine (interleukin (IL)-1β, IL-4, and IL-5) expression, and a correspondingly significant increase in Th1 cytokine (IL-12, interferon (IFN)-γ) production, was observed in nasal lavage fluid (NALF) taken from mice that received FA or Dex treatment. FA also reduced the presence of OVA-specific immunoglobulin (Ig) E, OVA-specific IgG1, and histamine levels in serum, and inhibited mast cell degranulation in vitro. In addition, these effects were involved with the reduction in NF-κB phosphorylation. These results suggest that FA restores Th1/Th2 balance and inhibits NF-κB phosphorylation and mast cell degranulation, thereby achieving a notable anti-inflammatory effect. Accordingly, it has the potential to be used as an efficacious therapeutic treatment for AR.  相似文献   
209.
A series of N-(4,5-dihydro-[1,2,4]triazolo[4,3-a]quinolin-7-yl)-2-(piperazin-1-yl)acetamide derivatives were synthesized and their positive inotropic activity was evaluated by measuring left atrium stroke volume on isolated rabbit heart preparations. Several compounds showed favorable activity compared with the standard drug, milrinone, among which N-(1-benzyl-4,5-dihydro-[1,2,4]triazolo[4,3-a]quinolin-7-yl)-2-(4-benzylpiperazin-1-yl)acetamide 6j was found to be the most potent with the 13.2% increased stroke volume (milrinone 4.7%) at concentration of 3x10(-5) M in our in vitro study. The chronotropic effects of those compounds having inotropic effects were also evaluated in this work.  相似文献   
210.
Neonatal injection of recombinant adeno-associated virus serotype 8 (rAAV8) vectors results in widespread transduction in multiple organs and therefore holds promise in neonatal gene therapy. On the other hand, insertional mutagenesis causing liver cancer has been implicated in rAAV-mediated neonatal gene transfer. Here, to better understand rAAV integration in neonatal livers, we investigated the frequency and spectrum of genomic integration of rAAV8 vectors in the liver following intraperitoneal injection of 2.0 × 1011 vector genomes at birth. This dose was sufficient to transduce a majority of hepatocytes in the neonatal period. In the first approach, we injected mice with a β-galactosidase-expressing vector at birth and quantified rAAV integration events by taking advantage of liver regeneration in a chronic hepatitis animal model and following partial hepatectomy. In the second approach, we performed a new, quantitative rAAV vector genome rescue assay by which we identified rAAV integration sites and quantified integrations. As a result, we find that at least ~0.05% of hepatocytes contained rAAV integration, while the average copy number of integrated double-stranded vector genome per cell in the liver was ~0.2, suggesting concatemer integration. Twenty-three of 34 integrations (68%) occurred in genes, but none of them were near the mir-341 locus, the common rAAV integration site found in mouse hepatocellular carcinoma. Thus, rAAV8 vector integration occurs preferentially in genes at a frequency of 1 in approximately 103 hepatocytes when a majority of hepatocytes are once transduced in the neonatal period. Further studies are warranted to elucidate the relationship between vector dose and integration frequency or spectrum.  相似文献   
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