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51.
1 引言 传统的植物光合生理生态研究中,多用照度计来测定光照指标,它以人眼对光亮度的响应特性为基础,与植物叶片对光照的响应曲线差异很大;而太阳光谱中只有400—700nm的波段才是光合有效辐射 相似文献
52.
Tian-Yu Liang Li-Hai Lu Si-Yu Tang Zi-Hao Zheng Kai Shi Jing-Quan Liu 《World journal of stem cells》2023,15(4):150-164
Acute respiratory distress syndrome (ARDS) is a common and clinically devastating disease that causes respiratory failure. Morbidity and mortality of patients in intensive care units are stubbornly high, and various complications severely affect the quality of life of survivors. The pathophysiology of ARDS includes increased alveolar–capillary membrane permeability, an influx of protein-rich pulmonary edema fluid, and surfactant dysfunction leading to severe hypoxemia. At present, the main treatment for ARDS is mechanical treatment combined with diuretics to reduce pulmonary edema, which primarily improves symptoms, but the prognosis of patients with ARDS is still very poor. Mesen chymal stem cells (MSCs) are stromal cells that possess the capacity to self-renew and also exhibit multilineage differentiation. MSCs can be isolated from a variety of tissues, such as the umbilical cord, endometrial polyps, menstrual blood, bone marrow, and adipose tissues. Studies have confirmed the critical healing and immunomodulatory properties of MSCs in the treatment of a variety of diseases. Recently, the potential of stem cells in treating ARDS has been explored via basic research and clinical trials. The efficacy of MSCs has been shown in a variety of in vivo models of ARDS, reducing bacterial pneumonia and ischemia-reperfusion injury while promoting the repair of ventilator-induced lung injury. This article reviews the current basic research findings and clinical applications of MSCs in the treatment of ARDS in order to emphasize the clinical prospects of MSCs. 相似文献
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54.
为了解珍稀濒危植物细果秤锤树(Sinojackia microcarpa)开花特征和有性繁殖,对其花部形态特征、开花动态、花粉胚珠比(P/O)、柱头可授性、花粉活力、套袋试验、访花昆虫及访花频率进行观测。结果表明:(1)细果秤锤树的杂交指数(OCI)为4,单花期5~7 d,种群花期可持续20 d左右。花粉与胚珠比为4 093.21±498.56。开花后第3天的花粉活力最高(76.21%),而开花后第7天时花粉活力较低(18.37%)。细果秤锤树柱头最适可授期在开花后第2天。(2)套袋试验表明,细果秤锤树存在部分自交不亲和性,同时不存在无融合生殖,传粉昆虫是其完成生殖过程所必需的,且异株授粉能够提高其坐果率和结籽率。细果秤锤树的访花昆虫有3目5科7种,主要访花昆虫有黄胸木蜂(Xylocopa appendiculata)、熊蜂(Bombus sp.)、胡蜂(Vespa sp.)、中华蜜蜂(Apis cerana)、黑带食蚜蝇(Episyrphus balteatus)、其中熊蜂平均访花频率最高,达(8.67±0.21) 次·h-1。对该物种开花生物学特征与繁育系统进行深入研究,有利于进一步探究其濒危机制,为后续珍稀濒危植物的研究提供理论依据和参考。 相似文献
55.
Lu‐Xian Liu Pan Deng Meng‐Zhen Chen Li‐Min Yu Joongku Lee Wei‐Mei Jiang Cheng‐Xin Fu Fu‐De Shang Pan Li 《植物分类学报:英文版》2023,61(1):99-114
Oresitrophe and Mukdenia (Saxifragaceae) are epilithic sister genera used in traditional Chinese medicine. The taxonomy of Mukdenia, especially of M. acanthifolia, has been controversial. To address this, we produced plastid and mitochondrial data using genome skimming for Mukdenia acanthifolia and Mukdenia rossii, including three individuals of each species. We assembled complete plastomes, mitochondrial CDS and nuclear ribosomal ETS/ITS sequences using these data. Comparative analysis shows that the plastomes of Mukdenia and Oresitrophe are relatively conservative in terms of genome size, structure, gene content, RNA editing sites and codon usage. Five plastid regions that represent hotspots of change (trnH-psbA, psbC-trnS, trnM-atpE, petA-psbJ and ccsA-ndhD) are identified within Mukdenia, and six regions (trnH-psbA, petN-psbM, trnM-atpE, rps16-trnQ, ycf1 and ndhF) contain a higher number of species-specific parsimony-informative sites that may serve as potential DNA barcodes for species identification. To infer phylogenetic relationships between Mukdenia and Oresitrophe, we combined our data with published data based on three different datasets. The monophyly of each species (Oresitrophe rupifraga, M. acanthifolia and M. rossii) and the inferred topology ((M. rossii, M. acanthifolia), O. rupifraga) are well supported in trees reconstructed using the complete plastome sequences, but M. acanthifolia and M. rossii did not form a separate clade in the trees based on ETS + ITS data, while the mitochondrial CDS trees are not well-resolved. We found low recovery of genes in the Angiosperms353 target enrichment panel from our unenriched genome skimming data. Hybridization or incomplete lineage sorting may be the cause of discordance between trees reconstructed from organellar and nuclear data. Considering its morphological distinctiveness and our molecular phylogenetic results, we strongly recommend that M. acanthifolia be treated as a distinct species. 相似文献
56.
57.
The gene (alyVI) encoding an alginate lyase of marine bacterium Vibrio sp. QY101, which was isolated from a decaying thallus of Laminaria, was cloned using a strategy of combined degenerate PCR and long range-inverse PCR (LR-IPCR), then sequenced and expressed in Escherichia coli. Gene alyVI was composed of a 1014 bp open reading frame (ORF) encoding 338 amino acid residues. The calculated molecular mass of alyVI product is 38.4 kDa, but a signal peptide is cleaved off, leaving a mature protein of 34 kDa. AlyVI was purified from culture supernatants to electrophoretic homogeneity using affinity chromatography. AlyVI was most active at pH 7.5 and 40 degrees C in the presence of 1 mM ZnCl2. A nine-amino-acid consensus region (YXRESLREM), which was only found in polyguluronate lyases, was also observed in the amino-terminal region of AlyVI. However, AlyVI could degrade both M block and G block. These results indicate that a novel alginate lyase-encoding gene has been cloned. 相似文献
58.
59.
Torsten Müller Stefan Fiedler Thomas Schnelle Kai Ludwig Hartmut Jung Günter Fuhr 《Biotechnology Techniques》1996,10(4):221-226
Summary Combining dielectrophoretic and hydrodynamic forces in micro electrode structures allows enrichment and stable trapping of viruses in aqueous solutions. Fluorescently labelled Influenza and Sendai viruses were collected from solutions of 2*105 – 2*108 viruses/l within a few seconds. In the central part of the trap a virus aggregate of about 2–9 m in diameter was formed. This corresponds to a local enrichment of viruses up to a factor of about 1400. 相似文献
60.
本研究在离体大鼠肠系膜血管床灌流模型上,采用特异放免法测定灌流液中的降钙素基因相关肽(CGRP),观察几种常见炎症介质在内毒素引起CGRP释放中的作用。结果显示:前列腺素合成酶抑制剂地塞米松、布洛芬与消炎痛,缓激肽受体B2拮抗剂HOE140,血小板激活因子拮抗剂WEB2086,组胺H1受体拮抗剂苯海拉明以及和组胺H2受体拮抗剂西咪替丁,均能明显抑剂制内毒素引起的CGRP释放,5羟色胺受体拮抗剂ICS205930却无明显作用。从而提示:内毒素引起CGRP释放是通过炎症介质前列腺素、缓激肽、血小板激活因子和组胺介导的,阻断或减少炎症介质的产生可望减轻内毒素血症时CGRP的过量释放。 相似文献