人类情绪或可影响干细胞生长

<正>南方医科大学南方医院杨默课题组发现,影响人类情绪和抑郁症的血清素与骨髓干细胞的生长分化及移植有密切关系。相关成果近日发表在《干细胞》杂志上。课题组根据研究结果提出:影响人类情绪与抑郁症的血清素与骨髓干细胞的生长分化及移植有密切关系。情绪低落可导致血清素下降,引起干细胞功能受损,影响损伤细胞修复和血细胞再生,从而影响身体免疫功能。这是医学界首次从科学角度证实人类情绪与干细胞生长之间     

格网尺度下典型旅游城市生态服务价值估算和时空分异特征——以三亚为例

以典型旅游城市三亚市为案例地，利用2006-2018年4期Landsat遥感影像数据，借助ENVI、ArcGIS平台定量识别土地利用演变特征，在1km×1km格网尺度下估算旅游地生态系统服务价值，并结合空间探索性数据分析揭示生态系统服务价值时空分异特征及其与旅游地发展的时空耦合关系。结果表明：（1）2006-2018年间，三亚市生态系统服务价值总量呈逐年下降趋势，由6.73×10⁹元降至5.76×10⁹元，累计减少9.78×10⁸元；（2）空间格局上，三亚市呈"南低北高"空间分异格局，2006-2018年增值区域连片分布于崖州区、天涯区、吉阳区南部区域，且呈逐年减少趋势，减值区域集聚于天涯区东北部、海棠区；（3）空间集聚上，生态系统服务价值截面各年份均呈显著空间正相关且相关性先降后增。高高集聚区位于天涯区北部区域，低低集聚区分布于沿海、海湾地区；（4）旅游发展与生态系统服务价值时空演化特征关联性较强。三亚市天涯区北部林地生态环境良好，生态系统服务价值略有下降但绝对数值稳定，是生态系统服务价值主要来源；旅游发展较为迅速的三亚湾、崖州湾以及海棠湾，相对增值区域较多，但绝对生态系统服务价值损失显著，严重滞后于其他区域。     

植物学专业英语的特征和翻译——评《植物学词汇手册》

熟练掌握专业英语是开阔视野、了解国内外专业领域研究进展以及丰富专业知识的重要前提。专业英语的学习与应用和普通英语有所区别。在进行专业英语的学习和应用时,应重点关注并掌握专业英语的文体特征、词汇特点以及翻译技巧,这为提高专业英语应用能力,适应学术研究的国际大环境奠定坚实的语言基础,进而促进相关领域的研究与发展。     

A Putative Calcium-Permeable Cyclic Nucleotide-Gated Channel, CNGC18, Regulates Polarized Pollen Tube Growth

A tip-focused Ca^2＋ gradient is tightly coupled to polarized pollen tube growth, and tip-localized influxes of extracellular Ca^2＋ are required for this process. However the molecular identity and regulation of the potential Ca^2＋ channels remains elusive. The present study has implicated CNGC18 （cyclic nucleotide-gated channel 18） in polarized pollen tube growth, because its overexpression induced wider and shorter pollen tubes. Moreover, CNGC18 overexpression induced depolarization of pollen tube growth was suppressed by lower extracellular calcium （[Ca^2＋]ex）. CNGC18-yellow fluorescence protein （YFP） was preferentially localized to the apparent post-Golgi vesicles and the plasma membrane （PM） in the apex of pollen tubes. The PM localization was affected by tip-localized ROP1 signaling. Expression of wild type ROP1 or an active form of ROP1 enhanced CNGC18-YFP localization to the apical region of the PM, whereas expression of RopGAP1 （a ROP1 deactivator） blocked the PM localization. These results support a role for PM-Iocalized CNGC18 in the regulation of polarized pollen tube growth through its potential function in the modulation of calcium influxes.     

Effects of peach branches returning on autotoxins and microbes in soil and tree growth of peaches

Aims This study aimed to investigate the effects of branch returning on the growth of peach (Amygdalus persica "Chunmei/Maotao") saplings, soil enzyme activity, and soil contents of phenolic acids and amygdalin, thereby providing scientific evidence against the application of branch returning for peach trees. Methods One-year-old potted peach tree (Amygdalus persica "Chunmei/Maotao") was used in this study with four agricultural treatments applied, including soil coverage by fragmented peach tree branches (fragment treatment;1.5 and 22.5 g·kg^-1) and applying leachate solutions of peach tree branches to soil (leachate treatment; 1.5 and 22.5 g·kg^-1). No branch addition was used as control (CK). Solid phase extraction, high performance liquid chromatography (HPLC), biological high-throughput sequencing was used to determine the content of autotoxic substances, and microbial community structure in soil. Soil coverage and leachate solution treatments of 30 g and 450 g branches applied to the peach trees were described as 1.5 and 22.5 g·kg^-1, respectively in this paper.Important findings Compared with CK, the phenolic acid and amygdalin contents significantly increased after both fragment and leachate treatments in high quantities (22.5 g·kg^-1). Soil microbial community structure altered in both treatments, with the proportion of fungi (particularly Agaricomycetes, Tubeufia and Cystofilobasidiaceae) increased significantly and bacteria decreased accordingly. Invertase activity in both high-quantity treatments exceeded that in the CK significantly. The activity of catalase and urease was higher at first and then decreased relative to CK under high-quantity fragment and leachate treatments. Specifically, the effect of leachate treatment on enzyme activity was higher than the fragment treatment in the short term. Chlorophyll content, ground diameter (diameter of 5 cm from the ground) growth and net photosynthesis rate of plants were lower in high-quantity fragment and leachate treatments than those in CK, with earlier retardation of new shoot growth. We observed an increase in soil phenolic acids and enzymes in treatments in normal pruning quantity, while no inhibition effect was found on the tree growth. In conclusion, autotoxins (such as phenolic acid and amygdalin) inhibited the growth of peach trees both directly and indirectly through changing soil enzyme activity and microbial community.