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1.
Highly pathogenic avian influenza H5N1 virus clades 2.3.4, 2.3.2, and 7 are the dominant cocirculating H5N1 viruses in poultry in China. However, humans appear to be clinically susceptible mostly to the 2.3.4 virus clade. Here, we demonstrated that A549 cells and human macrophages infected with clade 2.3.4 viruses produced significantly more viruses than those infected with the other two clades. Likewise, clade 2.3.4-infected macrophages caused the most severe cellular damage and strongest proinflammatory response.  相似文献   
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孢粉学是解决植物分类中疑难类群物种微形态分化的重要方法,随着分子系统学的发展,结合这两门学科的优势可以更加有效地解决疑难类群的分类学问题。鳞盖蕨属(Microlepia)是一个分类困难的疑难类群,采用孢粉学与分子系统学一一对应的方法,以及居群取样方式,选取280份样本,联合4个叶绿体片段(rbcL、trnL-F、psbA-trnH和rps4),采用最大似然法和贝叶斯法构建该属的系统发生关系,在此基础上对凭证标本中100份材料的孢子进行观察和分析。综合分子系统学和孢粉学的研究结果,得出结论:(1)在形态学研究中广泛被接受的15个物种得到了单系支持,并厘清了分类困难的复合群;(2)发现边缘鳞盖蕨(M. marginata)可能存在隐性种;(3)建议恢复过去归并处理为异名的瑶山鳞盖蕨(M. yaoshanica)、罗浮鳞盖蕨(M. lofoushanensis)、四川鳞盖蕨(M. szechuanica)以及滇西鳞盖蕨(M. subspeluncae);(4)提出鳞盖蕨属可能存在杂交现象;(5)提出鳞盖蕨属完整的属下分类建议。  相似文献   
3.
凉山州新银合欢根瘤菌的共生有效性及遗传多样性   总被引:1,自引:0,他引:1  
【目的】研究分离自四川凉山州新银合欢根瘤菌的遗传多样性和共生有效性。【方法】采用16S rRNA RFLP、BOX-PCR、AFLP、多位点持家基因序列的联合分析及无氮水培法对33株供试新银合欢根瘤菌的遗传多样性和共生有效性进行研究。【结果】分析表明,3种方法在属水平的分群结果具有较好的一致性,有1个Mesorhizobium属的菌株、3个Bradyrhizobium属的菌株、3个Rhizobium属的菌株,26个相似度较高的菌株属Sinorhizobium。16S rRNA-recA-atpD-glnII序列联合构建的新银合欢根瘤菌系统发育树表明,SCAU203、SCAU211可能分别是Rhizobium和Bradyrhizobium的新类群,另外3个代表菌株分别位于Sinorhizobium、Mesorhizobium、Bradyrhizobium分支,分别与S.americanum、M.Plurifarium、R.huautlense亲缘关系最近。无氮水培接种试验筛选出2个共生固氮效果好、与不接种对照处理差异达显著水平的菌株SCAU229和SCAU307,有3个菌株不仅不具共生有效性,甚至不利于宿主的生长,其余84%的供试菌为低效或无效菌株。【结论】凉山州新银合欢根瘤菌具有丰富的遗传多样性,分布于4个属:Rhizobium、Bradyrhizobium、Mesorhizobium、Bradyrhizobium,79%为Sinorhizobium属的菌株,优势菌群为Sinorhizobium。该区的新银合欢根瘤菌大多数的共生有效性差。  相似文献   
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Most imprinted genes are concerned with embryonic development, especially placental development. Here, we identified a placenta-specific imprinted gene Qpct. Our results show that Qpct is widely expressed during early embryonic development and can be detected in the telecephalon, midbrain, and rhombencephalon at E9.5–E11.5. Moreover, Qpct is strikingly expressed in the brain, lung and liver in E15.5. Expression signals for Qpct achieved a peak at E15.5 during placental development and were only detected in the labyrinth layer in E15.5 placenta. ChIP assay results suggest that the modification of histone H3K4me3 can result in maternal activating of Qpct.  相似文献   
7.
Research has shown that microRNAs are promising biomarkers that can be used to promote a more accurate diagnosis of cancer. In this study, we developed an integrated multi-step selection process to analyze available high-throughput datasets to obtain information on microRNAs as cancer biomarkers. Applying this approach to the microRNA expression profiles of prostate cancer and the datasets in The Cancer Genome Atlas Data Portal, we identified miRNA-182, miRNA-200c and miRNA-221 as possible biomarkers for prostate cancer. The associations between the expressions of these three microRNAs with clinical parameters as well as their diagnostic capability were studied. Several online databases were used to predict the target genes of these three microRNAs, and the results were confirmed by significant statistical correlations. Comparing with the other 18 types of cancers listed in The Cancer Genome Atlas Data Portal, we found that the combination of both miRNA-182 and miRNA-200c being up-regulated and miRNA-221 being down-regulated only happens in prostate cancer. This provides a unique biological characteristic for prostate cancer that can potentially be used for diagnosis based on tissue testing. In addition, our study also revealed that these three microRNAs are associated with the pathological status of prostate cancer.  相似文献   
8.
In this paper, an analogue of hirsutine (compound 1) has been synthesized and evaluated as an anti-hypertension agent, which exhibits extraordinary effects on the contractile response of thoracic aorta rings from male SD rats in vitro (IC50 = 1.129×10-9±0.5025) and the abilities of reducing the systolic blood pressure (SBP) and heart rate (HR) of SHR in vivo. The mechanism investigation reveals that the vasodilatation induced by compound 1 is mediated by both endothelium-dependent and -independent manners. The relaxation in endothelium-intact aortic rings induced by compound 1 can be inhibited by L-NAME (1×10-6 mol•L-1) and ODQ (1×10-6 mol•L-1). Moreover, compound 1 can also block Ca2+ influx through L-type Ca2+ channels and inhibit intracellular Ca2+ release while no effect on K+ channel has been observed. All these data demonstrated that the NO/cyclic GMP pathway can be involved in endothelium-dependent manner induced by compound 1. Meanwhile the mechanism on the vasodilatation of compound 1 probably also related to blockade of Ca2+ influx through L-type Ca2+ channels and inhibition of intracellular Ca2+ release may have no relationship with K+ channels.  相似文献   
9.
In this paper, the author studies the quartic bioecology differential system:Here n and q are positive constants, l、m and p are constants. The author also proves some theorems of existence and uniqueness of limit cycles of this differential system.  相似文献   
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