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131.
Ke Huang Jiaxing Zu Yangjian Zhang Nan Cong Yaojie Liu Ning Chen 《Journal of Plant Ecology》2019,12(3):583
Aims
Snow cover occupies large percentage of land surface in Tibetan Plateau. Snow cover duration (SCD) during non-growing seasons plays a critical role in regulating alpine vegetation’s phenology by affecting the energy budgets of land surface and soil moisture conditions. Different period’s snow cover during non-growing season may have distinct effect on the vegetation’s phenology. Start of season (SOS) has been observed advanced under the ongoing climate change in the plateau, but it still remains unclear how the SCD alters the SOS. This study attempts to answer the following questions: (i) What is the pattern of spatial and temporal variations for SCD and grassland SOS? (ii) Which period’s SCD plays a critical role in grassland’s SOS? 相似文献
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Tingting An Mingjie Xu Tao Zhang Chengqun Yu Yingge Li Ning Chen Jiaxing Zu Junxiang Li Juntao Zhu Yi Sun Tingting Zhao Guirui Yu 《Journal of Plant Ecology》2019,12(5):834
Aims
Evapotranspiration (ET) is an important component of the terrestrial water cycle and is easily affected by external disturbances, such as climate change and grazing. Identifying ET responses to grazing is instructive for determining grazing activity and informative for understanding the water cycle. 相似文献
133.
Xiao‐Yong Fan Jiaxing Han Yuan‐Li Ding Ya‐Ping Deng Dan Luo Xiangtian Zeng Zhen Jiang Lei Gou Dong‐Lin Li Zhongwei Chen 《Liver Transplantation》2019,9(28)
Alloying electrodes are regarded as promising anodes for lithium/sodium storage thanks to their multielectron reaction capacity, moderate voltage plateau, and high electrical conductivity. However, huge volume change upon cycling, especially for sodium storage, usually causes the loss of electrical connection between active components and their delaminations from traditional current collectors, thus leading to rapid capacity decay. Herein, a unique 3D current collector is assembled from 1D nanowire arrays anchored on 3D porous Cu foams for constructing core‐shelled Cu@Sb nanowires as advanced sodium‐ion battery (SIB) anodes. The so‐formed hierarchical 3D anode with interconnected 3D micrometer sized pores and abundant voids between nanowires not only effectively accommodates the structural strains during repeated cycling but also ensures the structural integrity and contributes to a uniform ion/electron scattered distribution throughout the whole surface. When employed as anodes for SIBs, the obtained electrode shows a high capacity of 605.3 mAh g?1 at 330 mA g?1, and demonstrates a high capacity retention of 84.8% even at a high current density of 3300 mA g?1. The 3D nanowire arrayed Cu current collector in this work can offer a promising strategy for designing and building advanced alloy anodes for lithium/sodium storage. 相似文献
134.
Among the antimicrobial peptides, abaecin is rich in proline content and plays a vital role in insect innate immune defense. Here, the full-length gene of abaecin from the bumblebee Bombus lantschouensis was cloned, and its expression profiles for different tissues, developmental stages and reproductive statuses were analyzed by RT-qPCR. Meanwhile, the responses of abaecin to a bacterium (Escherichia coli) and a fungus (Beauveria bassiana) were tested. The full length of abaecin cDNA was 470 bp, and the open reading frame (ORF) was 258 bp, encoding a polypeptide of 85 amino acids. The abaecin gene consists of three exons and two introns. Phylogenetic analysis showed that Bombus ignitus was the closest species to B. lantschouensis base on putative Abaecin protein sequence. Expression analysis showed that abaecin was expressed broadly in different tissues, with the highest expression in fat bodies and extremely low expression in antennae. Regarding developmental stage, low expression of abacein was detected in eggs and larvae, and high expression was detected in pupal stages. The highest expression was observed at the Pw pupal stage (pupae with an unpigmented body cuticle and white eyes), and the expression then decreased from the Pp (pupae with pink eyes) to the Pdd (dark-eye pupae with a dark-pigmented cuticle) stages. In addition, the expression of abaecin was higher in egg-laying than in non-egg-laying female bumblebees. Both E. coli and B. bassiana infections induced the expression of abaecin. Our results indicated that the abaecin gene plays important roles in the development, reproduction and immune responses of bumblebees. During the artificial rearing of bumblebees, a good environment should be created to avoid infection with bacteria or fungi. 相似文献
135.
Background
The results of the studies that have investigated the effects of black tea on blood cholesterol are inconsistent. The aim of this study is to quantitatively assess the effects of black tea on cholesterol concentrations.Methods
PubMed, Embase, MEDLINE, and Cochrane Library (through to July 2014) were searched for randomized controlled trials (RCTs) designed to investigate the effect of black tea on blood cholesterol concentrations. The study quality was assessed by the Jadad scoring criteria. Pooled effect of black tea consumption on blood cholesterol concentrations was evaluated by fixed-effects or random-effects model. Meta-regression analyses were conducted to estimate dose effects of black tea polyphenols on concentrations of blood cholesterol. Subgroup and sensitivity analyses were performed to assess the potential source of heterogeneity.Results
The consumption of black tea did not significantly lower TC concentrations either in healthy subjects or patients with coronary artery diseases based on both fixed-effects and random-effects analysis. No significant change was observed in HDL-C concentrations in healthy participants or in subjects with coronary artery disease supplemented with black tea when compared with control participants. The pooled net change of LDL-C in healthy participants was −5.57 mg/dL (95% CI, −9.49 to −1.66 mg/dL; P = 0.005) in fixed-effects analysis and −4.56 (95% CI, −10.30 to 1.17 mg/dL; P = 0.12) in random-effects analysis. No significant net change was observed in LDL-C concentrations in patients with coronary artery disease. Subgroup and sensitivity did not significantly influence the overall outcomes of this meta-analysis. No significant dose effects of black tea polyphenols on blood cholesterol concentrations were detected in meta-regression analyses.Conclusion
The meta-analysis suggests that the consumption of black tea might not have beneficial effects on concentrations of TC, HDL-C, and LDL-C. Further high quality RCTs are needed to definitively draw a causal interpretation of the findings. 相似文献136.
Jilian Li Jiaxing Huang Wanzhi Cai Zhangwu Zhao Wenjun Peng Jie Wu 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2010,180(2):161-170
In this present study, the cDNA of Bombus hypocrita vitellogenin (Vg) was cloned and sequenced. It is composed of 5,478 bp and contains an ORF of 1,772 amino acids within a
putative signal peptide of 16 residues. The deduced amino acid sequence shows significant similarity with Bombus ignitus (95%) and Apis mellifera (52%) and a high number of conserved motifs. Close to the C terminus there is a GL/ICG motif followed by nine cysteines,
and a DGXR motif is located 18 residues upstream from the GL/ICG motif. Moreover, we predicted the 3D structure of B. hypocrita Vg. Furthermore, the Vg mRNA of B. hypocrita was spatio-temporally analyzed in different castes (such as queen, worker and drone) from pupae to adult. The Vg mRNA was
found in the white-eyed pupal (Pw) stage in queens, and the expression increased during the entire pupal development and attained
its peak in the dark brown pupal stage. It also had a high expression in the adult fat body. In workers, the Vg expression
was detected in the Pw stage, and its levels increased with age with the highest in 15 days. Afterward, it decreased progressively.
Vg mRNA was also observed in drones, with a higher level of expression shown in only freshly molted adult drones. 相似文献
137.
【目的】开发可用于在极端嗜热嗜酸模式泉古菌冰岛硫化叶菌(Sulfolobus islandicus)中进行高效表达的eCGP123(enhanced consensus green protein variant 123)荧光蛋白,并用作S.islandicus的细胞内蛋白定位工具。【方法】绿色荧光蛋白突变体eCGP123具有极高的热稳定性、耐酸性和可逆的荧光特性等。本研究主要对eCGP123的基因根据S.islandicus密码子偏好性进行优化与合成,在大肠杆菌(Escherichia coli)中表达并研究其蛋白性质;通过在eCGP123的C末端分别融合具有不同细胞内定位的蛋白(包括E.coli来源的Fts Z和S.islandicus来源的Ups E、PCNA1和SiRe_1200等),构建eCGP123及其融合蛋白的表达菌株,用激光共聚焦显微镜分析eCGP123及其融合蛋白在E.coli和S.islandicus活细胞中的亚细胞定位。【结果】我们确认了在E.coli中表达并纯化密码子优化后的e CGP123具有与野生型绿色荧光蛋白相同的吸光值和较高的热稳定性。细胞学分析显示细胞分裂相关蛋白FtsZ和Si Re_1200分别主要定位于E.coli和S.islandicus分裂细胞的中间;鞭毛组分蛋白Ups E呈点状均匀分布,可能定位于细胞膜上;DNA复制滑动夹亚基PCNA1呈区域性点状分布,暗示了DNA复制区域的位置。蛋白的亚细胞定位与预期结果基本吻合。【结论】绿色荧光蛋白e CGP123可以作为报告蛋白,应用于S.islandicus细胞的蛋白定位分析中,可作为该模式菌株中功能基因研究的重要工具,但需要进一步优化条件。 相似文献
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箭叶淫羊藿具有重要的药用价值和较大的市场需求,但其种子休眠和萌发特性目前仍不够清楚,严重影响了其产业化育苗与栽培。为探明其种子的休眠类型及释放休眠和促进休眠的最适方法,该文以箭叶淫羊藿的成熟种子为材料,研究种子对水分的吸收、种子的脱水耐性,以及温度、层积和植物激素对种子休眠与萌发的影响。结果表明:(1)箭叶淫羊藿种子不具有物理休眠,而具耐脱水性。(2)在4~25℃和黑暗条件下,种子萌发率为零,具有休眠特性。(3)胚与种子的比值非常小,4℃和10℃及变温层积能显著地促进胚的生长发育以及增加种子的萌发速率和萌发率。(4)赤霉素和氟啶酮显著增加种子的萌发速率和萌发率。综上认为,箭叶淫羊藿种子的休眠类型为形态生理休眠(MPD),释放休眠和促进萌发的最适方法是先将种子在10℃中层积30 d,再置于4℃环境中让其萌发。该研究结果为箭叶淫羊藿的产业化育苗提供了参考。 相似文献