油菜素甾醇类与生长素的相互作用

油菜素甾醇类(brassinosteroid,BR)和生长素是两类重要的植物激素,二者在许多生理功能上存在相关性。近年来的研究表明,BR与生长素能协同调节基因表达,二者在代谢、运输和信号转导途径等不同层次上存在相互作用,并且这两种信号与其他信号转导途径,如激素信号转导途径和光信号转导途径之间也存在信号对话。现对BR与生长素之间这种复杂的相互作用进行评述。     

植物激素信号之间的相互作用

植物激素问的相互作用对植物的正常发育来说非常重要。不同植物激素之间存在相互协同、对抗和因果等关系,以精细调控植物的发育和对环境的反应等,植物激素信号之间的相互作用已成为植物细胞中不同信号间相互作用机制研究的模式系统。现对不同植物激素在生物合成、代谢、运输和信号转导途径等层次上的相互作用进行综述,并对这一领域的研究进行了总结和展望。     

芸薹素与其他植物激素相互作用的研究进展

芸薹素是植物中发现的固醇类激素,对植物的生长和发育等起着非常重要的作用,而这些重要的生理功能通常又需要通过与其它植物激素的相互作用.主要对芸薹素与其他植物激素之间相互作用的研究进展进行了综述.     

生长素与油菜素甾醇相互作用机制的研究进展

植物生长发育是一个复杂、精细的调控过程,涉及细胞、组织和器官间多层次的信息交流,激素在其间发挥了重要调控作用．生长素和油菜素甾醇（BR）都能促进植物伸长,随着对其作用机制研究的深入,人们发现它们协同调控很多生理过程,对二者作用机制和信号转导的相互作用研究也成为激素研究领域的热点之一．对生长素和BR转导途径的揭示及直接下游基因的大规模发掘为二者通过相互作用调控不同生理过程的机制研究提供了重要线索．生长素和BR的相互作用涉及到下游基因转录的调控、信号组分互作以及合成代谢和极性运输等多层次的调控．     

生长素信号转导研究进展

长素的信号转导是一个复杂的网络系统,在信号的感知上,除了存在ABPI介导的膜上感知途径外,还有其他的感知途径。G蛋白参与诱导生长素信号的胞内传递,生长素信号转导的第二信使包括离子型第二信使、磷酯酶A2、脂活化蛋白激酶、MAPK和PINOIND等。AUX／IAA蛋白的泛素化降解在生长素反应中发挥关键性作用,ARF和AUX／IAA蛋白相互作用调节生长素响应基因的转录。     

植物激素信号间的相互作用(综述)

本文从植物激素信号转导过程中特殊基因的鉴定、植物激素信号间、激素与糖之间的相互作用,以及激素对种子萌发和发育的影响等方面,概述近年来植物激素信号间相互作用的研究进展。     

植物激素与植物病害的相互作用

概述了病原真菌、细菌、病毒、类病毒、植原体及线虫等侵染性因子致病过程中各种植物激素代谢的变化,病害发展与激素变化之间的联系,内源激素变化方式和激素病理代谢机制,以及激素参与的抗病反应和信号转导等方面的研究现状和进展。     

生长素信号转导途径与植物胁迫反应相互作用的证据

生长素影响植物多种生理过程,有报道显示生长素可能影响植物对逆境胁迫的反应。我们利用cDNA阵列技术鉴定拟南芥（Arabiopsis thaliana (L.)Heynh.）的生长素应答基因,发现多个胁迫应答基因受生长素抑制,包括Arabidopsis homolog of MEK kinasel（ATMEKK1）,RelA/SpoT homolog 3(At-RSH3),Catalase 1(Cat1)和Ferriitn 1(Fer1)。说明生长素可调节胁迫应答基因的表达,此外,我们还证明吲哚乙酸（LAA）合成途径中的腈水解酶基因nitrilase 1(NIT1)和nitrilae 2（NIT2）受盐胁迫诱导,提示在逆境条件下1AA的合成可能随之增加,我们利用生长素不敏感突变体研究生长素与逆境反应相互作用的信号转导,发现胁迫应答基因在野生型和生长素不敏感突变体auxin resistant 2（axr2）中可被盐胁迫诱导,而在auxin resitant1-3（axl-3)中则不被诱导,说明生长素与逆境胁迫反应的相互作用可能发生在泛素途径。     

生长素的极性运输

生长素的极性运输李春俭（北京农业大学生物学院，北京１０００９４）ＰＯＬＡＲＡＵＸＩＮＴＲＡＮＳＰＯＲＴＬｉｎＣｈｕｎ－ｊｉａｎ（ＣｏｌｅｇｅｏｆＢｉｏｌｏｇｙ，ＢｅｉｊｉｎｇＡｇｒｉｃｕｌｔｕｒａｌＵｎｉｖｅｒｓｉｔｙ，Ｂｅｉｊｉｎｇ１０００９４）...     

非TIR1受体依赖型激活生长素信号的新机制

依赖于受体TIR1以及下游Aux/IAAs-ARFs介导的信号通路是目前研究最为深入的生长素信号转导途径。徐通达课题组最新研究发现, 高浓度生长素能够诱导质膜定位的TMK1激酶发生剪切, 导致其羧基(C-)端部分转入细胞核并磷酸化修饰细胞核内的非经典IAA32/34, 后者通过与生长素响应转录因子ARFs互作, 调控下游基因表达, 从而解析了生长素通过TMK1-IAA32/34-ARFs通路调控植物顶端弯钩内外侧差异性生长的分子机制。该研究发现了一条新的生长素TMK1- IAA32/34-ARFs信号途径, 此信号通路独立于经典生长素受体TIR1介导的生长素信号转导通路。     

Notch与相关调控信号的相互作用在伤口愈合中的调控

皮肤是哺乳动物最重要的组织之一.当皮肤受损时,受损组织通过系列伤口愈合反应的生理和心理作用被修复,实现组织再生.再生反应主要发生在胚胎发育早期,伤口自愈能力随着机体的成熟而减弱;并且哺乳动物的组织重塑过程较为复杂,在不正确的信号引导下,可能引起并发症而导致创面愈合异常.研究表明,伤口微环境的稳态和信号分子的辅助作用是愈...     

Assessment of Interaction Between Cardio-Respiratory Signals Using Directed Coherence on Healthy Subjects During Postural Change

PurposeTo detect and quantify the directional interaction changes between cardio-respiratory system during postural change.MethodTraditional frequency domain analysis based on power spectrum and coherence are insufficient to quantify nonlinear structures and complexity of physiological subsystems. Recently, Granger causality is found as preferable method for evaluation of causality i.e., directional interaction. Frequency domain Granger causality based on directed coherence has been used in this study to identify directional interaction between cardiac and respiratory signal during postural change from supine to standing for healthy subjects.ResultECG and respiration signal are recorded for this study. The beat-to-beat variability series from ECG provides heart rate (RR) and the respiration amplitude corresponds to RESP time series. It was observed that respiration is responsible for the changes in ECG signal during supine position as compared to standing. The outflow of information from RESP to RR increases during supine results in stronger interaction but reduces during standing result in reduction of interaction. Similarly, the effect of RR on RESP is found significant only during standing.ConclusionThe proposed directed coherence approach detects the cardio-respiratory regulation during postural change and provide information about coupling changes during this transition.     

Root Growth Activity of Barban in Relation to Auxin and Other Growth Factors

The effect of barban (4-Cl-2-butynyl-N-3-Cl-phenylcarbamate) on the growth of roots of wheat seedlings has been studied. In concentrations of 10^?7 to 5 · 10^?7M barban causes rapid inhibitions of cytokineses and cell elongation, the effects of which are spontaneously reversible. The reversion of the meristem inhibition is enhanced by thymidylic acid and indole-3-acetic acid (IAA). Initiation of cell elongation is slowed down or ceases during cytostasis; its reversal, on the other hand, is promoted by IAA and kinetin but inhibited by Fe. The final cell elongation attained is strongly reduced by barban and reversed under transient aberrant elongation. This inhibition and the recovery appear both to be additive to cell elongation actions of auxin and antiauxin but reversed by nucleic acid components. The inhibition of elongation is increased by Fe. The following explanation for this phenomenon is suggested: the primary effect of barban is known to be the blocking of metaphases under anaesthesis; this blocking then leads to reduced activation of IAA, kinetin and other metabolites. Auxin is required for cell divisions and initiation of elongation: the apical root growth equals in this respect that of shoot apices and lateral meristems. Initiation of cell elongation is closely dependent upon metabolites produced in dividing meristematic cells, whereas the limitation of cell stretching is independent of the meristem activity. No explanation is offered for the role of Fe.