Control Mechanism of Metabolism of Oligosaccharins Regulating Plant Growth

从植物或真菌细胞壁中提取的某些类型的寡糖具有不同的生理活性。这些被称为“寡糖素”的活性低聚糖似乎参与了高等植物生命周期的调节。据报道，低聚木糖在生长调节中起着重要的作用。本研究旨在阐明低聚木糖在细胞壁网络中的代谢是如何被原位调控的。1.研究了木葡聚糖寡糖(XG9或XXFG)和岩藻糖基乳糖对不同生长过程的影响。XG9和岩藻糖基乳糖都不影响生长素或酸诱导的赤霉酸诱导的生菜上胚轴的伸长、赤霉酸诱导的生菜下胚轴的生长、以及苯基腺嘌呤诱导的萝卜子叶的膨大。2.用针对低聚糖的抗体用ELISA法测定低聚木糖的内源浓度，用抗体和吡啶层析荧光标记的新微量测定法测定低聚木糖的内源浓度。木聚糖寡糖的含量估计为10^~(-8)M或更低。3.用1M的氯化钠从赤小豆上胚轴的细胞壁中提取了两种与低聚木糖的产生和降解有关的酶。木葡聚糖水解酶(内切-1，4-β-葡聚糖酶)和α-岩藻糖苷酶分别用ConA-Sepharose、Mono-S、Superdex 75和Phenyl Superose柱纯化。两种酶均由几种同工酶组成。内切-1，4-β-葡聚糖酶在Mono-S柱上与纤维素酶明显分离，表现出不同的作用模式。α-岩藻糖苷酶不能降解Rho-硝基苯基-α-L岩藻糖苷，对木葡聚糖侧链有专一性。

Certain types of oligosaccharide derived from plant or fungal cell walls possess diverse physiological activities. These active oligosaccharides, called "oligosaccharins" appear to be involved in the regulation of life cycle of higher plants. It has been reported that xyloglucan oligosaccharides play an important role in growth regulation. The present study was undertaken to clarify how the metabolism of the xyloglucan oligosaccharins is regulated in situ in the cell wall network.1.The effect of xyloglucan nonasaccharide (XG9 or XXFG) and fucosyl-lactose on different growth processes was examined. Neither XG9 nor fucosyl-lactose did influence auxin- or acid-induced elongation of azuki bean epicotyl segments, gibberellic acid-induced growth of intact lettuce hypocotyls, or benzyladenine-induced expansion of radish cotyledons.2.The endogenous concentration of xyloglucan oligosaccharides was determined with ELISA assay employing antibodies specific for the oligosaccharides and with new microassay using the antibodies and pyridylamination fluorescence labeling. The level of xyloglucan oligosaccharides was estimated as 10^<-8> M or lower.3.Two types of enzyme that appear to be involved in the production and the degradation of xyloglucan oligosaccharides were extracted with 1 M NaCl from the cell wall preparation of azuki bean epicotyls. Xyloglucan-hydrolyzing enzymes (endo-1,4-beta-glucanase) and alpha-fucosidases were purified with Con A-Sepharose, Mono-S, Superdex 75, and Phenyl Superose columms. Both enzymes were composed of several isozymes. The endo-1,4-beta-glucanases were clearly separated from cellulase on a Mono-S column and exhibited different action patterns. alpha-Fucosidases did not hydrolyze rho-nitrophenyl-alpha-L-fucopyranoside and were specific for xyloglucan side chains.