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81.
White and soft calli were induced from the stemnodes of Angelica dahurica on MS medium containing lmg/L 2,4-D, and subcultured on the same medium with decreased concentration of the hormone for about half a year, until quite a number of embryogenic cell clusters were produced in calli. Protoplasts prepared only from this kind of callus were regenerable. The protoplasts-derived colonies were able to develop into embryos directly or to grow continously into calli as affected by the hormone and, in particular, by osmotic pressure in the culture medium. The embryos either formed directly or via callus stage were all capable of regenerating complete plants under proper culture conditions.  相似文献   
82.
本文是在调查粤北石灰岩山地植被的基础上,选出8种植物进行光能利用效率和蒸腾系数等生理生态学特性研究,并与非石灰岩山地较速生的荷木、藜蒴作比较,以筛选出适合石灰岩山地造林绿化的树种。结果表明,任豆、香椿与荷木、藜蒴的平均净光合速率(gCO2·m-2·d-1)分别为19.92,13.10,9.04和8.11;对光合有效辐射的利用效率(%)分别为4.21,4.59,2.71和2.52;蒸腾速率(gH2O·m-2·d-1)分别为2191,1266,1499和1133;蒸腾系数(gH2O·gDM-1)分别为164,144,244和209.说明任豆、香椿比荷木、藜蒴速生,光能利用效率、水分利用效率高,生态适应性强。光皮树、阴香的生长速度与荷木、藜蒴相似。菜豆树、桂花、铁榄、板栗的生长速度比荷木、藜蒴慢,但除板栗外都比较耐荫,对石灰岩山地环境也有较强的生态适应性。  相似文献   
83.
Calli of Saposhnikovia divaricata (Turcz.) Schischk. were induced from the roots of test tube seedlings cultured on MS medium containing 0.5 mg/L 2,4-D. Cell suspension was established by shaking the caul in liquid medium of the same components supplemented with 10% coconut milk. After the formation of embryogenic clusters, 2,4-D was omitted promoting the transformation of the embryogenic clusters to somatic embryos. Micro and submicroscopic: structural changes during the single cell to globular embryonic stage were observed. It was noticed that cortical endoplasmic reticulum appeared in the cells at the stage of embryogenic clump formation but was absent in other stages. Perhaps this was related to the metabolic specification leading to embryo formation. Spherosomes were observed of embryogenesis but remarkably increased in number at proglobular embryo stage. Meanwhile, the central electric dense matrix became progressively smaller and paler, while the outer part became enlarged and more transparent. This implied that the spherosomes took part in the storage of proteins or lipidproteins in the early stages of embryogenesis and transformation to lipid dror)s when the proteins were exhausted in the development of embryo, vacuolar protein bodies could be risualized in many cells in the proglobular embryo stage. This together with the existance and changes of spherosomes was similar to that observed in Peucedanum terebmthaceum. Further studies are meritted to approach, whether these are general phenomena in Umbelliferae. This work also revealed that the aggregation of single cells in suspension culture stimulated the initiation of embryogenesis.  相似文献   
84.
85.

Background

Mounting evidence supports the notion of “one airway, one disease.”

Objective

To determine whether chronic rhinosinusitis (CRS) poses adverse impacts on Chinese adults with bronchiectasis.

Methods

We enrolled 148 consecutive adults with clinically stable bronchiectasis. CRS diagnosed based on the 2012 EP3OS criteria. We systematically evaluated the bronchiectasis etiology, radiology, lung function, sputum bacteriology, airway inflammatory biomarkers, Bronchiectasis Severity Index, cough sensitivity and healthcare resource utilization. All patients were prospectively followed-up for 1 year to examine the frequency of bronchiectasis exacerbations (BEs).

Results

Forty-seven patients (31.8%) were diagnosed as having CRS. Bronchiectasis etiologies did not vary statistically between CRS and no-CRS group. There was a trend towards non-statistically higher Bronchiectasis Severity Index [6.4±3.4 vs. 5.0(6.0), P = 0.19], a higher proportion of patients with BEs needing hospitalization before enrollment (48.9% vs. 29.7%, P = 0.13), poorer FVC [78.2±19.8% vs. 82.2(16.8)%, P = 0.54] and FEV1 [68.2±24.8% vs. 74.8(21.2)%, P = 0.29], a higher prevalence of Pseudomonas aeruginosa isolated (36.2% vs. 26.7%, P = 0.27) or colonized in sputum (36.2% vs. 21.8%, P = 0.12) and greater capsaicin cough sensitivity [C2: 3.9(123.0) μmol/L vs. 11.7(123.0) μmol/L, P = 0.81; C5: 62.5(996.0) μmol/L vs. 250.0(973.0) μmol/L, P = 0.32]. Patients with CRS had significantly greater risks of experiencing BEs during follow-up (P = 0.02 for negative binominal regression test).

Conclusion

Chinese adults with bronchiectasis appear to have a lower prevalence of CRS than that in western countries. There was a trend towards greater adverse impacts on bronchiectasis in patients with CRS. Studies with greater sample sizes might help to resolve this issue. In future clinical practice, physicians should be vigilant to the screening of concomitant CRS in bronchiectasis so as to better improve patient’s healthcare. Our findings may be of clinical significance in that proper treatment of upper airway symptoms due to CRS will be the prevention of infection or re-infection of the tracheobronchial tree, which should be addressed for the future management of bronchiectasis.  相似文献   
86.
细根对生态系统养分、水分和碳循环至关重要。然而,目前关于森林生态系统细根可塑性的研究多集中于乔木树种,对灌木少有研究。本研究以杉木(乔木)和檵木(灌木)为研究对象,采用根袋法研究种内竞争和残落物覆盖对2物种1级和2级细根形态特征(比根长、直径和分枝比)及养分吸收能力的影响,揭示种内竞争和林下管理措施(残落物覆盖)对2物种细根塑性和养分吸收策略的影响机制。结果表明:残落物覆盖、种内竞争及二者的交互作用对杉木细根形态特征各指标均无显著影响。残落物覆盖显著提高了檵木1、2级根分枝比,残落物覆盖、种内竞争及二者的交互作用均显著降低了檵木1级根的直径。檵木细根属性的这些变化增加了其细根的养分吸收速率。因此,增加杉木林残落物覆盖使林下檵木细根形态特征的变化更利于土壤养分的高效吸收,进而可能会与同土层中塑性差的杉木细根产生养分竞争。  相似文献   
87.
RIG-I-like receptors (RLRs: RIG-I, MDA5 and LGP2) play a major role in the innate immune response against viral infections and detect patterns on viral RNA molecules that are typically absent from host RNA. Upon RNA binding, RLRs trigger a complex downstream signaling cascade resulting in the expression of type I interferons and proinflammatory cytokines. In the past decade extensive efforts were made to elucidate the nature of putative RLR ligands. In vitro and transfection studies identified 5′-triphosphate containing blunt-ended double-strand RNAs as potent RIG-I inducers and these findings were confirmed by next-generation sequencing of RIG-I associated RNAs from virus-infected cells. The nature of RNA ligands of MDA5 is less clear. Several studies suggest that double-stranded RNAs are the preferred agonists for the protein. However, the exact nature of physiological MDA5 ligands from virus-infected cells needs to be elucidated. In this work, we combine a crosslinking technique with next-generation sequencing in order to shed light on MDA5-associated RNAs from human cells infected with measles virus. Our findings suggest that RIG-I and MDA5 associate with AU-rich RNA species originating from the mRNA of the measles virus L gene. Corresponding sequences are poorer activators of ATP-hydrolysis by MDA5 in vitro, suggesting that they result in more stable MDA5 filaments. These data provide a possible model of how AU-rich sequences could activate type I interferon signaling.  相似文献   
88.
目的:研究菖远胶囊对大鼠长期大量用药后的安全性影响。方法:通过对大鼠连续灌胃菖远胶囊13周、26周和停药4周,分别与正常对照组比较血液、生化、病理学检查结果。结果:①菖远胶囊各剂量组给药后5~30 min动物自主活动有所减弱,30 min后自主活动逐渐恢复正常,各剂量组大小便颜色偏深,高剂量组比较明显,停止给药后,上述症状均恢复正常;②大鼠血液细胞学、生化学指标中有个别指标在给药初期(13周)出现明显差异,继续给药至26周,未见明显异常,停止给药后恢复正常;高剂量组动物体重有一定降低,个别脏器质量及指数增大,停药4周后均能恢复正常;病理检查结果示,菖远胶囊各剂量组主要脏器未见由药物引起的病理学改变;整个实验期间各组动物未见死亡;③大鼠长期给予菖远胶囊的安全剂量为4.0 g/kg。结论:菖远胶囊对动物的毒性较低,是值得开发的一个中药新药。  相似文献   
89.
90.
Foxp3(+) regulatory T (T(reg)) cells suppress different types of immune responses to help maintain homeostasis in the body. How T(reg) cells regulate humoral immunity, including germinal center reactions, is unclear. Here we identify a subset of T(reg) cells expressing CXCR5 and Bcl-6 that localize to the germinal centers in mice and humans. The expression of CXCR5 on T(reg) cells depends on Bcl-6. These CXCR5(+)Bcl-6(+) T(reg) cells are absent in the thymus but can be generated de novo from CXCR5(-)Foxp3(+) natural T(reg) precursors. A lack of CXCR5(+) T(reg) cells leads to greater germinal center reactions including germinal center B cells, affinity maturation of antibodies and the differentiation of plasma cells. These results unveil a Bcl-6-CXCR5 axis in T(reg) cells that drives the development of follicular regulatory T (T(FR)) cells that function to inhibit the germinal center reactions.  相似文献   
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