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《Current biology : CB》2014,24(10):R453-R462
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随着温室效应的加剧,全球气候变暖已经成为现代农业生产体系所面临的严峻挑战.高温灾害性气候是影响作物产量的一种主要的非生物胁迫.因此,对于农作物生产而言,研究植物耐热信号转导机制不仅有重要的科学意义,而且有现实的紧迫性.最近几年,在阐明植物耐热信号转导机制的研究方面取得了很多重要的进展,这些进展涵盖植物高温胁迫的感受机制、热激转录因子和热激蛋白的表达调控、热激转录因子结合蛋白参与耐热性调控的分子机制等几个主要的方面.热胁迫影响细胞膜系统、RNA、蛋白质的稳定性,同时改变酶的活性和细胞骨架系统.当热胁迫来临时,植物的转录组会发生显著变化,所涉及的基因大约占基因组的2%.这些高温胁迫响应基因构成了热激响应网络,是植物抵御热胁迫的第一道防线.植物的耐热性分为基础耐热性和获得性耐热性.基础耐热性是植物固有的耐热性.获得性耐热性是温和的热驯化诱导的耐热性.获得性耐热性状的形成反映了植物在自然生长环境下适应高温胁迫的生理机制. 相似文献
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The role of salicylic acid (SA) as a key molecule in the signal transduction pathway of biotic stress responses has already
been well described. Recent studies indicate that it also participates in the signaling of abiotic stresses. The application
of exogenous SA could provide protection against several types of stresses such as high or low temperature, heavy metals,
and so on. Although SA may also cause oxidative stress to plants, partially through the accumulation of hydrogen peroxide,
the results published so far show that the preliminary treatment of plants with low concentrations of SA might have an acclimation-like
effect, causing enhanced tolerance toward most kinds of abiotic stresses due primarily to enhanced antioxidative capacity.
The effect of exogenous SA depends on numerous factors such as the species and developmental stage of the plant, the mode
of application, and the concentration of SA and its endogenous level in the given plant. Recent results show that not only
does exogenous SA application moderate stress effects, but abiotic stress factors may also alter the endogenous SA levels
in the plant cells. This review compares the roles of SA during different abiotic stresses. 相似文献
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The unique chemistry of oxygen has been both a resource and threat for life on Earth for at least the last 2.4 billion years.
Reduction of oxygen to water allows extraction of more metabolic energy from organic fuels than is possible through anaerobic
glycolysis. On the other hand, partially reduced oxygen can react indiscriminately with biomolecules to cause genetic damage,
disease, and even death. Organisms in all three superkingdoms of life have developed elaborate mechanisms to protect against
such oxidative damage and to exploit reactive oxygen species as sensors and signals in myriad processes. The sulfur amino
acids, cysteine and methionine, are the main targets of reactive oxygen species in proteins. Oxidative modifications to cysteine
and methionine can have profound effects on a protein’s activity, structure, stability, and subcellular localization. Non-reversible
oxidative modifications (oxidative damage) may contribute to molecular, cellular, and organismal aging and serve as signals
for repair, removal, or programmed cell death. Reversible oxidation events can function as transient signals of physiological
status, extracellular environment, nutrient availability, metabolic state, cell cycle phase, immune function, or sensory stimuli.
Because of its chemical similarity to sulfur and stronger nucleophilicity and acidity, selenium is an extremely efficient
catalyst of reactions between sulfur and oxygen. Most of the biological activity of selenium is due to selenoproteins containing
selenocysteine, the 21st genetically encoded protein amino acid. The most abundant selenoproteins in mammals are the glutathione
peroxidases (five to six genes) that reduce hydrogen peroxide and lipid hydroperoxides at the expense of glutathione and serve
to limit the strength and duration of reactive oxygen signals. Thioredoxin reductases (three genes) use nicotinamide adenine
dinucleotide phosphate to reduce oxidized thioredoxin and its homologs, which regulate a plethora of redox signaling events.
Methionine sulfoxide reductase B1 reduces methionine sulfoxide back to methionine using thioredoxin as a reductant. Several
selenoproteins in the endoplasmic reticulum are involved in the regulation of protein disulfide formation and unfolded protein
response signaling, although their precise biological activities have not been determined. The most widely distributed selenoprotein
family in Nature is represented by the highly conserved thioredoxin-like selenoprotein W and its homologs that have not yet
been assigned specific biological functions. Recent evidence suggests selenoprotein W and the six other small thioredoxin-like
mammalian selenoproteins may serve to transduce hydrogen peroxide signals into regulatory disulfide bonds in specific target
proteins. 相似文献
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DREB转录因子与植物非生物胁迫抗性研究进展 总被引:4,自引:0,他引:4
干旱、高盐、低温等非生物逆境胁迫严重影响植物的生长发育和作物产量。转录因子在调节植物生长发育以及对外界环境胁迫的响应方面起着重要作用。DREB类转录因子即干旱应答元件结合蛋白是AP2/EREBP转录因子家族的一个亚家族,拥有保守的AP2结构域,能够与DRE/CRT顺式作用元件特异结合,在非生物逆境胁迫条件下调节一系列下游胁迫诱导逆境应答基因的表达,从而提高植物耐逆性。就DREB转录因子的结构特点、表达调控以及提高转基因植株胁迫耐受性的最新研究成果进行了评述。 相似文献
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Gaurav Dwivedi Margaret A. Gran Pritha Bagchi Melissa L. Kemp 《PLoS computational biology》2015,11(11)
Quantifying the magnitude and dynamics of protein oxidation during cell signaling is technically challenging. Computational modeling provides tractable, quantitative methods to test hypotheses of redox mechanisms that may be simultaneously operative during signal transduction. The interleukin-4 (IL-4) pathway, which has previously been reported to induce reactive oxygen species and oxidation of PTP1B, may be controlled by several other putative mechanisms of redox regulation; widespread proteomic thiol oxidation observed via 2D redox differential gel electrophoresis upon IL-4 treatment suggests more than one redox-sensitive protein implicated in this pathway. Through computational modeling and a model selection strategy that relied on characteristic STAT6 phosphorylation dynamics of IL-4 signaling, we identified reversible protein tyrosine phosphatase (PTP) oxidation as the primary redox regulatory mechanism in the pathway. A systems-level model of IL-4 signaling was developed that integrates synchronous pan-PTP oxidation with ROS-independent mechanisms. The model quantitatively predicts the dynamics of IL-4 signaling over a broad range of new redox conditions, offers novel hypotheses about regulation of JAK/STAT signaling, and provides a framework for interrogating putative mechanisms involving receptor-initiated oxidation. 相似文献
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李丽刘双清杨远航戴良英李魏 《生物技术进展》2018,8(3):214-220
植物在遭受环境胁迫时会产生一系列应激反应,而热激转录因子可通过介导热激蛋白或其他热诱导基因的转录和表达,来参与调控植物抵抗逆境胁迫过程和其他生命活动。主要介绍了植物热激转录因子的基本蛋白结构域,阐述了3类热激转录因子在抗极端温度(高温、低温)胁迫、干旱胁迫、高盐胁迫、活性氧胁迫中的功能与作用机制,并探讨和展望了植物热激转录因子在植物育种和提高植物抗逆性的研究中的发展与应用前景,以期为深入研究热激转录因子在调控植物抵抗逆境胁迫中的生物学功能与机制提供理论参考。 相似文献
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Global change puts an increasing pressure on tropical forests and their inherent diversity by the risk of longer droughts and drier microclimatic conditions within the forest. How organisms will respond is uncertain, especially for organisms highly depending on their microclimatic environment such as bryophytes. An adequate tolerance to desiccation is important to face these changes, however, little is known for tropical bryophytes. We investigated for the first time the desiccation tolerance of epiphytic bryophytes from contrasting microsites at the tropical lowland forest in French Guiana. Using chlorophyll‐fluorescence (Fv/Fm) as an indicator of recovery, we tested: (1) desiccation tolerance for short (3 d) and long (9 d) desiccation events; (2) different desiccation intensities; and (3) recovery by rehydration with water vapor. Species from the canopy were well adapted to desiccation events. Thirteen of 18 species maintained more than 75 percent of their photosynthetic capacity after recovery at the strongest desiccation treatment of 9 d at 43 percent relative humidity (RH). In contrast, species from the understory were sensitive and withstood desiccation only at humid conditions of 75 percent RH and higher. The photosystem of the studied bryophytes was reactivated efficiently in equilibration with water vapor only—a yet neglected phenomenon in bryology. A novel introduced desiccation tolerance index allows global comparison of desiccation tolerances and highlights the sensitivity of understory species. Our results suggest that decreasing humidity caused by climate change and forest degradation could be a concerning threat for understory species. 相似文献
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干旱、低温、土地盐碱化等非生物胁迫是影响植物生长发育以及作物产量的重要因素。近年来大量研究表明,多种转录因子参与调控植物对各种生物及非生物胁迫的应答与防御反应,与此同时人们对其作用机理的探索也日渐深入。AP2/ERF转录因子家族是植物所特有的一类转录因子,在拟南芥中该家族至少有146个成员;而在水稻中该基因家族多达181个,是已知水稻转录因子基因中最大的家族。这些编码含有一个保守APETALA(AP2)结构域的蛋白质可能在植物多个发育过程及应答外界环境信号过程中发挥重要功能。综述了AP2/EREBP类转录因子的结构特征及其功能特性,并重点讨论了它们在植物抗逆中的调控作用及其在植物抗逆性分子遗传改良上的意义。 相似文献
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Shinya Toyokuni 《Biotherapy》1998,11(2-3):147-154
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Nicole Hassoun 《PloS one》2015,10(12)
Millions of people cannot access essential medicines they need for deadly diseases like malaria, tuberculosis (TB) and HIV/AIDS. There is good information on the need for drugs for these diseases but until now, no global estimate of the impact drugs are having on this burden. This paper presents a model measuring companies’ key malaria, TB and HIV/AIDS drugs’ consequences for global health (global-health-impact.org). It aggregates drugs’ impacts in several ways–by disease, country and originator-company. The methodology can be extended across diseases as well as drugs to provide a more extensive picture of the impact companies’ drugs are having on the global burden of disease. The study suggests that key malaria, TB and HIV/AIDS drugs are, together, ameliorating about 37% of the global burden of these diseases and Sanofi, Novartis, and Pfizer’s drugs are having the largest effect on this burden. Moreover, drug impacts vary widely across countries. This index provides important information for policy makers, pharmaceutical companies, countries, and other stake-holders that can help increase access to essential medicines. 相似文献