Differential Subcellular Distribution of Cytokinins: How Does Membrane Transport Fit into the Big Picture?

Cytokinins are a class of phytohormones, signalling molecules specific to plants. They act as regulators of diverse physiological processes in complex signalling pathways. It is necessary for plants to continuously regulate cytokinin distribution among different organs, tissues, cells, and compartments. Such regulatory mechanisms include cytokinin biosynthesis, metabolic conversions and degradation, as well as cytokinin membrane transport. In our review, we aim to provide a thorough picture of the latter. We begin by summarizing cytokinin structures and physicochemical properties. Then, we revise the elementary thermodynamic and kinetic aspects of cytokinin membrane transport. Next, we review which membrane-bound carrier proteins and protein families recognize cytokinins as their substrates. Namely, we discuss the families of “equilibrative nucleoside transporters” and “purine permeases”, which translocate diverse purine-related compounds, and proteins AtPUP14, AtABCG14, AtAZG1, and AtAZG2, which are specific to cytokinins. We also address long-distance cytokinin transport. Putting all these pieces together, we finally discuss cytokinin distribution as a net result of these processes, diverse in their physicochemical nature but acting together to promote plant fitness.     

细胞分裂素6─BA合成新方法的研究

用医药工业的副产物乙酰基次黄嘌呤（Ⅰ）在弱酸条件下水解，生成次黄嘌呤（Ⅱ），经三氟氧磷在吡啶溶液中缩合，生成６－吡啶盐中间体（Ⅲ），再与苄胺反应，制得高效植物细胞分裂素６－ＢＡ（Ⅳ）。     

含1,3,4-噻二唑环氟取代苯基脲的合成及细胞分裂素活性

以取代肉桂酸和氨基硫脲为原料、以三氯氧磷为脱水剂经缩合-环化"一锅法"制备2-氨基-5-取代苯乙烯基-1,3,4-噻二唑,再与含氟苯甲酰基叠氮化物反应合成9种新的含氟取代苯基脲类化合物。其结构经红外光谱、核磁共振氢谱、质谱和元素分析所确认。初步的生物活性测试表明,目标化合物在10 mg/L浓度下表现出良好的细胞分裂素活性,促进率超过50%。     

Suppression of postharvest blue mould of apple fruit by Cryptococcus laurentii and N6‐benzyladenine

BACKGROUND: Cryptococcus laurentii is a well‐known postharvest yeast antagonist. N⁶‐benzyladenine (6‐BA), a cytokinin plant hormone, has a role in retarding ripening and senescence of harvested produce. This study was conducted to evaluate the efficacy of C. laurentii and 6‐BA in reducing the blue mould disease of apple fruit. RESULTS: The combination of C. laurentii with 6‐BA (20 µg mL^?1) was more effective in suppressing the Penicillium expansum infection in apple fruit wounds than C. laurentii alone, although 6‐BA (20 µg mL^?1) alone neither affected the growth of C. laurentii nor reduced the incidence of the blue mould disease in vivo. Moreover, treatment of apple fruit with C. laurentii and 6‐BA (20 µg mL^?1) resulted in stimulation of superoxide dismutase activity but in inhibition of the increase in peroxidase activity. CONCLUSION: 6‐BA (20 µg mL^?1) could enhance the efficacy of C. laurentii in reducing the postharvest blue mould disease of apple fruit, which offered great potential in minimizing the postharvest decay of apple fruit in an integrated pest management strategy. Copyright © 2008 Society of Chemical Industry     

几个含噻二唑环芳甲酰基脲的合成及生物活性

通过2-氨基-5-(3-吡啶基)-1,3,4-噻二唑与取代苯甲酰基异氰酸酯反应,得到相应的芳甲酰基脲:N-[5-(3-吡啶基)-1,3,4-噻二唑-2-基]-N′-(2-氯苯甲酰基)脲(Ⅲa)、N-[5-(3-吡啶基)-1,3,4-噻二唑-2-基]-N′-(2-溴苯甲酰基)脲(Ⅲb)、N-[5-(3-吡啶基)-1,3,4-噻二唑-2-基]-N′-(4-溴苯甲酰基)脲(Ⅲc)、N-[5-(3-吡啶基)-1,3,4-噻二唑-2-基]-N′-(2-甲基苯甲酰基)脲(Ⅲd)和N-[5-(3-吡啶基)-1,3,4-噻二唑-2-基]-N′-(4-三氟甲基苯甲酰基)脲(Ⅲe),收率分别为69.5%、67.2%、73.1%、66.8%和71.6%.产物的结构经红外光谱、核磁共振氢谱、质谱与元素分析表征.并对目标化合物进行了植物生长调节活性测试,初步的测试结果表明,目标化合物在10 mg/L表现出一定程度的生长素活性和较好的细胞分裂素活性,其中Ⅲc和Ⅲe的细胞分裂素活性超过40%.     

腺嘌呤类细胞分裂素的合成及结构-活性关系

讨论了腺嘌呤类细胞分裂素的合成方法及其结构-活性关系。     

1,3,4-噻二唑基脲类含氟衍生物的合成及生物活性

以含氟肉桂酸和氨基硫脲为原料、以三氯氧磷为脱水剂,经缩合-环化"一步法"反应制备2-氨基-5-含氟苯乙烯基-1,3,4-噻二唑,再与含氟苯甲酰基叠氮化物反应合成6种1,3,4-噻二唑基脲类含氟衍生物,收率分别为68%、69%、66%、67%、71%和73%。目标化合物的结构用IR、1HNMR、质谱和元素分析进行了表征。初步的生物活性测试表明,目标化合物Ⅲc和Ⅲd在10 mg/L质量浓度下表现出良好的细胞分裂素活性,促进率分别为53.5%和55.1%。     

5-氨基三氮唑羧酸酯Schiff碱的合成及其植物激素活性

合成了16个5－氨基－1H－1,2,4－三氮唑－3－羧酸酯的Schiff碱,讨论了它们的物理性质,UV、IR、^1HNMR和元素分析数据。生物活性测试试验表明,一些化合物具有明显的植物激素活性,其中化合物Ia、Ib、Ic、Ⅱb、Ⅱc等具有良好的细胞分裂素活性,含氯的芳醛生成的Schiff碱生物活性较优。