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1.
Polyploid organisms have more than two sets of chromosomes, including autopolyploid via intraspecific genome doubling, and allopolyploid via merging genomes of distinct species by hybridization. Polyploid organisms are widespread in plants, indicating that polyploidy has some evolutionary advantages over its diploid ancestor. Actually, polyploidy is always tightly associated with hybrid vigor and adaptation to adverse environmental conditions. However, why polyploidy can develop such advantages is poorly known. MicroRNAs (miRNAs) are endogenous ~21?nt small RNAs which can play important regulatory roles in animals and plants by targeting mRNAs for cleavage or translational repression. MicroRNAs are essential for cell development, differentiation, signal transduction, and show an adaptive response to biotic and abiotic stresses. Environmental stresses cause plants to over- or under-express certain miRNAs or synthesize new miRNAs to cope with stress. We have here reviewed our current knowledge on the molecular mechanisms, which can account for the evolutionary advantages of polyploidy over its diploid ancestor from genome-wide gene expression and microRNAs expression perspectives.  相似文献   
2.
蒙古栎、白桦根系分解及养分动态   总被引:1,自引:0,他引:1  
靳贝贝  国庆喜 《生态学报》2013,33(8):2416-2424
采用埋袋法对蒙古栎(Quercus mongolica)、白桦(Betula platyphylla)两个树种粗根(>10 mm)、中粗根(5—10 mm)、中根(2—5 mm)和细根(<2 mm)的分解速率和养分动态进行研究。结果表明,根系的重量保持率随时间增加呈下降趋势,这种趋势可用Olson指数衰减模型来拟合,即:Xt/X0=e-kt(t为分解时间,X0为根系初始干重,Xt为分解t时间的残留干重,k为年分解系数),通过拟合计算出年分解系数k。在本研究中,蒙古栎粗根、中粗根、中根、细根的年分解系数分别为:0.2928、0.2562、0.2928、0.3660;白桦依次分别为:0.2196、0.3294、0.3660、0.4392,基本呈现随直径增加分解速率减小的趋势。根系分解过程中,两树种各径级均是N浓度增加,可溶性糖浓度减小。在根系分解的不同时期两树种各径级N表现出不同程度的释放或富集,没有明显的规律性;可溶性糖却一直处于释放状态。分解1a时间,蒙古栎各径级根系表现为释放N元素;白桦表现为细根和中根释放N元素,中粗根和粗根富集N元素。蒙古栎、白桦细根和中根可溶性糖的释放率达90%以上,中粗根和粗根的释放率达80%以上。  相似文献   
3.
B cell activating factor from the TNF family (BAFF) stimulates B‐cell proliferation and survival, but excessive BAFF promotes the development of aggressive B cells leading to malignant and autoimmune diseases. Recently, we have reported that rapamycin, a macrocyclic lactone, attenuates human soluble BAFF (hsBAFF)‐stimulated B‐cell proliferation/survival by suppressing mTOR‐mediated PP2A‐Erk1/2 signaling pathway. Here, we show that the inhibitory effect of rapamycin on hsBAFF‐promoted B cell proliferation/survival is also related to blocking hsBAFF‐stimulated phosphorylation of Akt, S6K1, and 4E‐BP1, as well as expression of survivin in normal and B‐lymphoid (Raji and Daudi) cells. It appeared that both mTORC1 and mTORC2 were involved in the inhibitory activity of rapamycin, as silencing raptor or rictor enhanced rapamycin's suppression of hsBAFF‐induced survivin expression and proliferation/viability in B cells. Also, PP242, an mTORC1/2 kinase inhibitor, repressed survivin expression, and cell proliferation/viability more potently than rapamycin (mTORC1 inhibitor) in B cells in response to hsBAFF. Of interest, ectopic expression of constitutively active Akt (myr‐Akt) or constitutively active S6K1 (S6K1‐ca), or downregulation of 4E‐BP1 conferred resistance to rapamycin's attenuation of hsBAFF‐induced survivin expression and B‐cell proliferation/viability, whereas overexpression of dominant negative Akt (dn‐Akt) or constitutively hypophosphorylated 4E‐BP1 (4EBP1‐5A), or downregulation of S6K1, or co‐treatment with Akt inhibitor potentiated the inhibitory effects of rapamycin. The findings indicate that rapamycin attenuates excessive hsBAFF‐induced cell proliferation/survival via blocking mTORC1/2 signaling in normal and neoplastic B‐lymphoid cells. Our data underscore that rapamycin may be a potential agent for preventing excessive BAFF‐evoked aggressive B‐cell malignancies and autoimmune diseases.  相似文献   
4.
BackgroundTo explore the associations of serum high-sensitivity C-reactive protein (hs-CRP) and prealbumin (PAB) with the number of diseased coronary vessels, degree of stenosis and heart failure in patients with myocardial infarction (MI).MethodsA total of 39 MI patients treated in the Cardiology were selected as the observation group, and another 41 patients with normal results of coronary angiography during the same period were selected as the control group. The general data of patients were recorded in detail, the content of serum hs-CRP and PAB in the peripheral blood was detected, and the number of diseased coronary vessels and the degree of stenosis were detected via coronary angiography.ResultsCompared with those in control group, the blood pressure and heart rate significantly rose, the content of indexes related to the severity of MI were significantly increased, the content of hs-CRP was significantly increased, and the content of PAB was significantly decreased in observation group. Hs-CRP was positively correlated with the number of diseased coronary vessels, degree of stenosis and heart failure in patients, but PAB was negatively correlated with the above factors. The survival rate of MI patients with high content of hs-CRP was obviously lower than that of patients with low content of hsCRPConclusionsSerum hs-CRP and PAB are closely associated with the number of diseased coronary vessels, degree of stenosis and heart failure in MI patients.  相似文献   
5.
将区域作为一个以人类生产和消费为中心的社会-经济-自然复合生态系统,构建了一种基于生物物理视角的生态热力学方法,从整体角度对区域的可持续发展水平进行定量评价。该方法囊括了维持复合生态系统运转过程中的自然资源投入、人力资源投入和环境污染损害成本投入等三种要素,完善了可持续发展评价以及绿色GDP核算中人力资源投入和环境成本的价值体现。然后以我国为例,核算了我国31个省市2006—2015年间可持续发展水平的时间动态,并以各省为边界,计算了2015年的区域可持续发展水平差异。计算结果显示:(1)十年间,我国整体上的可持续发展水平在逐步提高,能反映出我国生产率水平的提高和资源利用效率的提高;(2)从要素投入看,自然资源投入仍然占主要,但比例在逐渐降低。环境成本投入比例呈逐步降低趋势,说明环境保护取得了成效。另外,在2010年后,人力资源投入比例增加很快,反映了我国经济发展中劳动力成本上升明显。(3)各省市的计算结果差异较大,在不考虑区域间进出口的情况下,从GDP产出角度,北京的可持续发展水平最高,西藏最低。通过将本文的评价结果与绿色发展指数的评价结果进行比较,发现具有较好的一致性。建立的方法框架是对能值分析方法的扩展和完善,在今后的研究中,还需要继续对该方法框架中没有考虑全面的因素加以考虑,以便于更全面客观地反映区域的可持续发展水平。  相似文献   
6.
Li  Guoli  Su  Bingqian  Fu  Pengfei  Bai  Yilin  Ding  Guangxu  Li  Dahua  Wang  Jiang  Yang  Guoyu  Chu  Beibei 《中国科学:生命科学英文版》2022,65(2):341-361
Science China Life Sciences - Viruses utilize cellular lipids and manipulate host lipid metabolism to ensure their replication and spread. Therefore, the identification of lipids and metabolic...  相似文献   
7.
Huang B  Guo J  Yi B  Yu X  Sun L  Chen W 《Biotechnology letters》2008,30(7):1121-1137
Heterologous expression of genes involved in the biosynthesis of various products is of increasing interest in biotechnology and in drug research and development. Microbial cells are most appropriate for this purpose. Availability of more microbial genomic sequences in recent years has greatly facilitated the elucidation of metabolic and regulatory networks and helped gain overproduction of desired metabolites or create novel production of commercially important compounds. Saccharomyces cerevisiae, as one of the most intensely studied eukaryotic model organisms with a rich density of knowledge detailing its genetics, biochemistry, physiology, and large-scale fermentation performance, can be capitalized upon to enable a substantial increase in the industrial application of this yeast. In this review, we describe recent efforts made to produce commercial secondary metabolites in Saccharomyces cerevisiae as pharmaceuticals. As natural products are increasingly becoming the center of attention of the pharmaceutical and nutraceutical industries, such as naringenin, coumarate, artemisinin, taxol, amorphadiene and vitamin C, the use of S. cerevisiae for their production is only expected to expand in the future, further allowing the biosynthesis of novel molecular structures with unique properties.  相似文献   
8.
Early diagnosis of lung adenocarcinoma requires effective risk predictors. TNFRII was reported to be related to tumorigenesis, but remained unclear in lung cancer. This research set out to investigate the relationship between the sTNFRII (serum TNFRII) level and the risk of lung adenocarcinoma less than 1 cm in diameter. Seventy-one pairs of subcentimetre lung adenocarcinoma patients and healthy controls were analysed through multiplex bead-based Luminex assay and found a significantly lower expression of sTNFRII in patients with subcentimetre lung adenocarcinoma than that in the healthy controls (P < .001), which was further verified through ONCOMINE database analysis. Increased levels of sTNFRII reduced the risk of subcentimetre lung adenocarcinoma by 89% (P < .001). Patients with a higher level of BLC had a 2.70-fold (P < .01) higher risk of subcentimetre adenocarcinoma. Furthermore, a higher BLC/TNFRII ratio was related to a 35-fold higher risk of subcentimetre adenocarcinoma. TNFRII showed good specificity, sensitivity and accuracy (0.72, 0.75 and 0.73, respectively), with an AUC of 0.73 (P < .001). In conclusion, the present study assessed the value of sTNFRII as a potential biomarker to predict the risk of subcentimetre lung adenocarcinoma and provided evidence for the further use of TNFRII as an auxiliary marker in the diagnosis of subcentimetre lung adenocarcinoma.  相似文献   
9.
Compared to conjugated polymers, small‐molecule organic semiconductors present negligible batch‐to‐batch variations, but presently provide comparatively low power conversion efficiencies (PCEs) in small‐molecular organic solar cells (SM‐OSCs), mainly due to suboptimal nanomorphology. Achieving precise control of the nanomorphology remains challenging. Here, two new small‐molecular donors H13 and H14 , created by fluorine and chlorine substitution of the original donor molecule H11 , are presented that exhibit a similar or higher degree of crystallinity/aggregation and improved open‐circuit voltage with IDIC‐4F as acceptor. Due to kinetic and thermodynamic reasons, H13 ‐based blend films possess relatively unfavorable molecular packing and morphology. In contrast, annealed H14 ‐based blends exhibit favorable characteristics, i.e., the highest degree of aggregation with the smallest paracrystalline π–π distortions and a nanomorphology with relatively pure domains, all of which enable generating and collecting charges more efficiently. As a result, blends with H13 give a similar PCE (10.3%) as those made with H11 (10.4%), while annealed H14 ‐based SM‐OSCs have a significantly higher PCE (12.1%). Presently this represents the highest efficiency for SM‐OSCs using IDIC‐4F as acceptor. The results demonstrate that precise control of phase separation can be achieved by fine‐tuning the molecular structure and film formation conditions, improving PCE and providing guidance for morphology design.  相似文献   
10.
Chrysanthemum is one of the most important ornamental flowers in the world, and temperature has a significant influence on its field production. In the present study, differentially expressed proteins were investigated in the leaves of Dendranthema grandiflorum ‘Jinba’ under high temperature stress using label-free quantitative proteomics techniques. The expressed proteins were comparatively identified and analyzed. A total of 1,463 heat-related, differentially expressed proteins were successfully identified by Liquid Chromatography-tandem Mass Spectrometry (LC-MS/MS), and 1,463 heat-related, differentially expressed proteins were successfully identified by mass spectrometry after a high temperature treatment. Among these, 701 proteins were upregulated and 762 proteins were downregulated. The in-depth bioinformatics analysis of these differentially expressed proteins revealed that these were involved in energy metabolism pathways, protein metabolism, and heat shock. In the present study, the investigators determined the changes in the levels of some proteins, and their expression at the protein and molecular levels in chrysanthemum to help reveal the mechanism of heat resistance in chrysanthemum. Furthermore, the present study elucidated some of the proteins correlated to heat resistance in chrysanthemum, and their expression changes at the protein and molecular levels to help reveal the mechanism of heat resistance in this flower species. These results provide a theoretical basis for the selection of new heat resistant varieties of chrysanthemum in the field.  相似文献   
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