Potassium and phosphorus transport and signaling in plants

Nitrogen(N), potassium(K), and phosphorus(P) are essential macronutrients for plant growth and development, and their availability affects crop yield. Compared with N, the relatively low availability of K and P in soils limits crop production and thus threatens food security and agricultural sustainability. Improvement of plant nutrient utilization efficiency provides a potential route to overcome the effects of K and P deficiencies. Investigation of the molecular mechanisms underlying how plants sense, absorb, transport, and use K and P is an important prerequisite to improve crop nutrient utilization efficiency. In this review, we summarize current understanding of K and P transport and signaling in plants, mainly taking Arabidopsis thaliana and rice(Oryza sativa) as examples. We also discuss the mechanisms coordinating transport of N and K, as well as P and N.     

低温胁迫下红松与西伯利亚红松光合与气孔特性

红松与西伯利亚红松均为寒温带著名的成林树种,具有较强的耐寒性,与红松相比,西伯利亚红松具有更强的耐寒性。为探究低温胁迫下两树种的生理响应机制及抗寒生理机理,本研究以5年生的红松与西伯利亚红松幼苗为材料,对其进行低温处理,3个胁迫温度(0℃、-20℃和-40℃)和3个胁迫时间(6、24和48 h),20℃为对照,研究低温胁迫下红松与西伯利亚红松的光合特性和气孔特性。T检验和方差分析结果表明,各光合指标和气孔密度在红松与西伯利亚红松中的差异显著(P<0.05),低温及低温胁迫时间对红松与西伯利亚红松各光合指标具有极显著影响(P<0.01),低温对红松与西伯利亚红松的气孔开度与气孔面积具有极显著影响(P<0.01)。胁迫前(20℃)和0℃低温胁迫下,红松中的净光合速率、气孔导度和蒸腾速率均显著高于西伯利亚红松,但在-20℃条件下胁迫6 h,西伯利亚红松各光合测定指标显著高于红松。随着温度的降低与胁迫时间的延长,两树种的各光合指标均呈下降趋势。红松中的气孔密度显著高于西伯利亚红松,胁迫前(20℃),红松与西伯利亚红松的气孔均为椭圆形,随着温度的降低,两树种的气孔开度和气孔面积显著减小。     

不同地点51个长白落叶松无性系苗期生长变异和遗传稳定性分析

长白落叶松是我国东北林区非常重要的速生用材树种之一。以不同地点51个长白落叶松无性系为材料,对其2年生苗高和地径进行调查分析,探讨其苗期生长变异和遗传稳定性。结果表明:长白落叶松无性系苗高和地径在地点间、无性系间、地点×无性系间差异均达到极显著水平(P<0.01);不同地点苗高和地径的表型变异系数处于23.89%~36.82%,除四平试验点的地径重复力为0.172外,不同地点苗高和地径的重复力均处于0.573~0.891;遗传稳定性分析结果表明,无性系LO 13等28个无性系的遗传稳定性较高;相关分析结果表明苗高与地径呈极显著正相关关系;利用多性状综合评价法,以20%的入选率对无性系进行选择,不同地点均选出10个综合表现较好的无性系,其中无性系LO 10和LO 26在不同地点均被入选优良无性系,且其遗传稳定性较强,可将其初选为优良无性系。     

免疫球蛋白联合B族维生素对癫痫症状及生活质量的影响

目的:探讨免疫球蛋白联合B族维生素对癫痫症状及生活质量的影响。方法:2017年2月至2020年1月选择在本院诊治的癫痫患者78例,根据随机数字表法把患者分为观察组与对照组各39例。两组都给予常规治疗,对照组给予维生素B12治疗,观察组给予免疫球蛋白联合维生素B12治疗,记录两组治疗后症状与生活质量情况。结果:治疗后观察组的总有效率为97.4%,显著高于对照组的84.6%(P<0.05)。两组治疗期间的腹胀、嗜睡、胃痛、发热等不良反应情况对比差异无统计学意义(P>0.05)。治疗后两组的血清同型半胱氨酸(homocysteine,Hcy)含量低于治疗前,观察组也低于对照组,对比差异都有统计学意义(P<0.05)。观察组治疗后的精神健康、情感职能、社会功能、活力、总体健康、躯体疼痛、生理职能、生理功能等生活质量评分都显著高于对照组(P<0.05)。结论:免疫球蛋白联合B族维生素在癫痫患者的应用能促进改善临床症状,提高治疗效果,抑制Hcy的释放,且不增加患者不良反应的发生,从而提高生活质量。     

马氏珠母贝Caspase-3基因克隆和组织表达分析

半胱氨酸蛋白酶3 (Caspase-3)作为细胞凋亡通路中重要的效应蛋白,在细胞凋亡过程中发挥着重要作用.为初步探究马氏珠母贝Caspase-3(PmCaspase-3)的生物学功能,本研究利用cDNA末端快速扩增(RACE)技术克隆获得PmCaspase-3基因cDNA的全长序列并对其序列特征进行分析;同时利用实时荧光定量PCR (RT-qPCR)方法分析了PmCaspase-3基因mRNA在马氏珠母贝不同组织和不同发育时期的表达差异.结果 显示,PmCaspase-3基因cDNA全长为2233 bp,其中5'端非编码区长度为80 bp,3'端非编码长度为31 bp,开放阅读框长度为2088 bp,共编码695个氨基酸;生物信息学分析显示,PmCaspase-3含有Caspase家族特有的CASc结构域和半胱氨酸蛋白酶家族p20、p10活性位点以及多种磷酸化位点,经进化分析以及多序列比对可知与其他物种Caspase-3蛋白同源性较高.RT-qPCR结果表明,PmCaspase-3在肝胰腺中的表达量最高,在闭壳肌中的表达量最低;在发育过程中D型幼虫期和眼点期的表达量较高.     

Understanding the “SMART” features of hematopoietic stem cells and beyond

Science China Life Sciences - Since the huge success of bone marrow transplantation technology in clinical practice, hematopoietic stem cells (HSCs) have become the gold standard for defining the...     

Middle Jurassic radiolarians from Jinlang,Zedong, southern Xizang (Tibet), China

Moderately to well-preserved radiolarians have been extracted from nine greyish green and purplish-red bedded cherts in the mud-matrix mélange of the eastern Yarlung-Zangbo Suture Zone (YZSZ) at Jinlang Section, Zedong, southern Xizang (Tibet). Forty-two species belonging to 27 genera, including Middle Jurassic characteristic species such as Laxtorum (?) jurassicum Isozaki and Matsuda, Laxtorum (?) hichisoense Isozaki and Matsuda, Stichocapsa japonica Yao, Stichocapsa robusta Matsuoka, Parahsuum (?) magnum Takemura, Sella chrafatensis (El Kadiri), and Unuma typicus Ichikawa and Yao are recognized and three assemblages, Laxtorum (?) jurassicum Assemblage (Aalenian), Quarticella ovalis Assemblage (late Bajocian), and Stichocapsa robusta Assemblage (middle Bathonian) are established in ascending order. These assemblages can be well correlated to the Middle Jurassic Unitary Association (UA) Zones (Baumgartner et al., 1995) in west Tethys and coeval biozones in Japan and provide reliable age information for the Middle Jurassic stratigraphic correlation of the pelagic sediments along the YZSZ.     

A swine arterivirus deubiquitinase stabilizes two major envelope proteins and promotes production of viral progeny

Arteriviruses are enveloped positive-strand RNA viruses that assemble and egress using the host cell’s exocytic pathway. In previous studies, we demonstrated that most arteriviruses use a unique -2 ribosomal frameshifting mechanism to produce a C-terminally modified variant of their nonstructural protein 2 (nsp2). Like full-length nsp2, the N-terminal domain of this frameshift product, nsp2TF, contains a papain-like protease (PLP2) that has deubiquitinating (DUB) activity, in addition to its role in proteolytic processing of replicase polyproteins. In cells infected with porcine reproductive and respiratory syndrome virus (PRRSV), nsp2TF localizes to compartments of the exocytic pathway, specifically endoplasmic reticulum-Golgi intermediate compartment (ERGIC) and Golgi complex. Here, we show that nsp2TF interacts with the two major viral envelope proteins, the GP5 glycoprotein and membrane (M) protein, which drive the key process of arterivirus assembly and budding. The PRRSV GP5 and M proteins were found to be poly-ubiquitinated, both in an expression system and in cells infected with an nsp2TF-deficient mutant virus. In contrast, ubiquitinated GP5 and M proteins did not accumulate in cells infected with the wild-type, nsp2TF-expressing virus. Further analysis implicated the DUB activity of the nsp2TF PLP2 domain in deconjugation of ubiquitin from GP5/M proteins, thus antagonizing proteasomal degradation of these key viral structural proteins. Our findings suggest that nsp2TF is targeted to the exocytic pathway to reduce proteasome-driven turnover of GP5/M proteins, thus promoting the formation of GP5-M dimers that are critical for arterivirus assembly.     

New Phenylpropanoid Glycosides from Illicium majus and Their Radical Scavenging Activities

Chemical investigation of the ethanol extract of the branch and leaves of Illicium majus resulted in the isolation of four new phenylpropanoid glycosides ( 1 – 4 ) and one new phenolic glycoside ( 9 ), along with 13 known ones. Spectroscopic techniques were used to elucidate the structures of the new isolates such as 3-[(2R,3S)-7-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-3-(hydroxymethyl)-2,3-dihydro-1-benzofuran-5-yl]propyl β-D-glucopyranoside ( 1 ), [(2R,3S)-7-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-5-(3-hydroxypropyl)-2,3-dihydro-1-benzofuran-3-yl]methyl 2-O-α-L-rhamnopyranosyl-β-D-glucopyranoside ( 2 ), [(2R,3S)-7-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-5-(3-hydroxypropyl)-2,3-dihydro-1-benzofuran-3-yl]methyl 2-O-α-L-rhamnopyranosyl-β-D-xylopyranoside ( 3 ), 3-[(2R,3S)-3-({[2-O-(4-O-acetyl-α-L-rhamnopyranosyl)-β-D-xylopyranosyl]oxy}methyl)-7-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-2,3-dihydro-1-benzofuran-5-yl]propyl acetate ( 4 ), and 4-(2-hydroxyethyl)phenyl 3-O-β-D-glucopyranosyl-β-D-glucopyranoside ( 9 ). Free radical scavenging activities of the isolates were elucidated through the DPPH assay method. The most active compounds, 1-O-caffeoyl-β-D-glucopyranose ( 17 ) and soulieana acid 1 ( 18 ), exhibited moderate radical scavenging activities (IC₅₀=37.7±4.4 μM and IC₅₀=97.2±3.4 μM, respectively). The antibacterial activities of the isolates against Staphylococcus aureus and Escherichia coli were also assessed, and no activity was shown at the measured concentration (<32 μg/mL).