甘草叶片渗透调节物质及蔗糖代谢相关酶对干旱胁迫的响应特性

该研究以甘草幼苗为试材,采用盆栽自然干旱方法,设计对照(CK)、轻度(LS)、中度(MS)、重度(SS)干旱胁迫处理,测定分析甘草叶片的渗透调节物质及蔗糖代谢相关酶[蔗糖磷酸合成酶(SPS)、蔗糖合成酶合成方向(Ss+)、蔗糖合成酶分解方向(Ss-)、中性转化酶(NI)、酸性转化酶(AI)、淀粉磷酸化酶(SP)]活性的变化,以探讨甘草的渗透调节特性以及糖分调节的酶学机制,揭示甘草对干旱胁迫的响应机理。结果显示:(1)随着干旱胁迫程度的加剧,甘草叶片可溶性糖、可溶性蛋白和脯氨酸含量呈逐渐增加的趋势,束缚水/自由水的比值呈先增加后降低的趋势。(2)随着干旱胁迫程度的加剧,甘草叶片蔗糖、葡萄糖、果糖含量均呈先升高后降低的趋势,但不同胁迫强度出现峰值的时间不同;其中在CK和LS干旱胁迫时蔗糖含量淀粉含量葡萄糖含量果糖含量,在MS和SS干旱胁迫时淀粉含量葡萄糖含量蔗糖含量果糖含量,表明随着干旱程度的增加,甘草叶片中蔗糖转化成了淀粉。(3)随着干旱胁迫程度的加重,甘草叶片的SPS活性呈先升高后降低的趋势,Ss活性和Inv(蔗糖转化酶)活性呈逐渐升高的趋势,SP活性呈逐渐降低的趋势;各胁迫处理的Ss+活性与CK差异不显著,而Ss-活性与CK差异显著,并且Ss-活性在各胁迫处理下远大于Ss+活性,表明甘草叶片Ss-活性在蔗糖代谢过程中占主导作用。(4)相关分析结果显示,在LS中,NI与蔗糖呈负相关关系,Ss-与淀粉呈显著正相关关系、与蔗糖呈负相关关系;在MS中,蔗糖和葡萄糖与SPS、Ss+、Ss-、NI和AI均呈正相关关系,与SP呈负相关关系;在SS中,SP和NI与蔗糖呈正相关关系,而与淀粉呈负相关关系;表明在轻度干旱处理下,Ss参加了蔗糖的分解,继而合成淀粉;在中度和重度干旱条件下,SP主要催化淀粉的分解来增加蔗糖含量以此平衡蔗糖代谢。     

Involvement of Putrescine,Nitric Oxide,and Hydrogen Peroxide in Methyl Jasmonate-Induced Ginsenoside Synthesis in Adventitious Root Cultures of Panax ginseng C.A. Meyer

Journal of Plant Growth Regulation - The adventitious root (AR) culture of Panax ginseng C.A. Meyer is an alternative route for mass production of ginsenosides. During the AR culture of P. ginseng,...     

Plasticity of symbiont acquisition in new recruits of the massive coral Platygyra daedalea under ocean warming and acidification

Coral Reefs - Symbiosis establishment is a milestone in the life cycles of most broadcast-spawning corals; however, it remains largely unknown how initial symbiont infection is affected by ocean...     

LncRNA H19 rs4929984 Variant is Associated with Coronary Artery Disease Susceptibility in Han Chinese Female Population

Biochemical Genetics - Long non-coding RNAs (lncRNAs) have been reported to play an important role in cardiovascular diseases. The present study aimed to investigate the levels of lncRNA H19 in...     

Direct and size-mediated effects of temperature and ration-dependent growth rates on energy reserves in juvenile anadromous alewives (Alosa pseudoharengus)

Growth rate and energy reserves are important determinants of fitness and are governed by endogenous and exogenous factors. Thus, examining the influence of individual and multiple stressors on growth and energy reserves can help estimate population health under current and future conditions. In young anadromous fishes, freshwater habitat quality determines physiological state and fitness of juveniles emigrating to marine habitats. In this study, the authors tested how temperature and food availability affect survival, growth and energy reserves in juvenile anadromous alewives (Alosa pseudoharengus), a forage fish distributed along the eastern North American continent. Field-collected juvenile anadromous A. pseudoharengus were exposed for 21 days to one of two temperatures (21°C and 25°C) and one of two levels of food rations (1% or 2% tank biomass daily) and compared for differences in final size, fat mass-at-length, lean mass-at-length and energy density. Increased temperature and reduced ration both led to lower growth rates, and the effect of reduced ration was greater at higher temperature. Fat mass-at-length decreased with dry mass, and energy density increased with total length, suggesting size-based endogenous influences on energy reserves. Lower ration also directly decreased fat mass-at-length, lean mass-at-length and energy density. Given the fitness implications of size and energy reserves, temperature and food availability should be considered important indicators of nursery habitat quality and incorporated in A. pseudoharengus life-history models to improve forecasting of population health under climate change.     

Slc20a1b is essential for hematopoietic stem/progenitor cell expansion in zebrafish

Science China Life Sciences - Hematopoietic stem and progenitor cells (HSPCs) are able to self-renew and can give rise to all blood lineages throughout their lifetime, yet the mechanisms regulating...     

鼎湖山南亚热带常绿阔叶林植物功能性状变异与不同垂直层次个体生长的关联

建立植物功能性状与群落动态之间的关联是功能生态学的核心问题之一。本文基于鼎湖山1.44 ha塔吊样地的两次调查数据, 通过采集样地内所有4,142株个体的6种植物功能性状, 对比分析了个体水平植物功能性状和物种水平功能性状均值对不同垂直层次(灌木层、亚冠层和林冠层)个体生长的影响差异。首先, 分析了不同垂直层次下各植物功能性状的变化趋势; 其次, 计算了不同垂直层次下各植物功能性状的种内和种间变异水平; 最后, 运用结构方程模型探讨了植物功能性状、光竞争以及地下竞争对不同垂直层次树木生长的影响。结果表明: (1)不同垂直层次下的植物功能性状表现出明显的分异, 由灌木层至林冠层, 叶面积、比叶面积和能量供求关系指数显著降低, 而叶片厚度和叶片干物质含量显著升高; (2)不同垂直层次下植物功能性状的种间变异均大于种内变异, 且林冠层的种内功能性状变异均大于灌木层和亚冠层; (3)基于个体水平植物功能性状的结构方程模型较物种水平功能性状均值对生长具有更高的解释程度, 且个体水平植物功能性状的引入更有利于提高对灌木层个体生长的预测能力; (4)光竞争和地下竞争主要通过影响功能性状间接影响植物生长。由灌木层至林冠层, 同种间的相互作用逐渐减弱, 异种间的相互作用逐渐增强。综上, 将个体水平植物功能性状纳入分析有助于更好地理解群落的结构和动态。     

A new unique form of microRNA from human heart,microRNA-499c,promotes myofibril formation and rescues cardiac development in mutant axolotl embryos

Background

A recessive mutation “c” in the Mexican axolotl, Ambystoma mexicanum, results in the failure of normal heart development. In homozygous recessive embryos, the hearts do not have organized myofibrils and fail to beat. In our previous studies, we identified a noncoding Myofibril-Inducing RNA (MIR) from axolotls which promotes myofibril formation and rescues heart development.

Results

We randomly cloned RNAs from fetal human heart. RNA from clone #291 promoted myofibril formation and induced heart development of mutant axolotls in organ culture. This RNA induced expression of cardiac markers in mutant hearts: tropomyosin, troponin and α-syntrophin. This cloned RNA matches in partial sequence alignment to human microRNA-499a and b, although it differs in length. We have concluded that this cloned RNA is unique in its length, but is still related to the microRNA-499 family. We have named this unique RNA, microRNA-499c. Thus, we will refer to this RNA derived from clone #291 as microRNA-499c throughout the rest of the paper.

Conclusions

This new form, microRNA-499c, plays an important role in cardiac development.