低pH对水稻黄化叶片硝酸还原酶活性暗诱导的调节

在低pH条件下,水稻离体黄化叶片的硝酸还原酶(NR)活性能在暗中诱导产生,其诱导过程约有2h的滞后期,亚胺环已酮(CHI,5ppm)和Na_2WO_4(25 mmol/L)能完全抑制这种诱导作用。在最适pH 3.0时,H~3标记氨基酸掺入NR的量比pH 7.0时约高2倍,表明酶活性的产生与酶蛋白的重新合成有关。 当低pH暗诱导时,BA(5ppm)和ABA(15ppm)能使酶活性分别提高约30％和80％,但它们都不能取代低pH在NR活性暗诱导中的作用。当存在1ppm CHI的时候,BA仍促进NR活性,而ABA则加强CHI对酶活性的抑制作用,这提示BA与ABA在低pH暗诱导条件下促进NR活性的机制是不同的。在pH 7.0的光诱导条件下,ABA对NR活性起抑制作用。     

细胞分裂素促进小麦硝酸还原酶的诱导

细胞分裂素促进硝酸还原酶的诱导,脱落酸强烈抑制该酶的诱导,并抵消细胞分裂素的作用。6-苄基腺瞟呤(6-BA)的促进效应与 NO_3~-的诱导作用有关。无 NO_3~-存在时,6-BA 无直接诱导作用,适宜浓度的 NO_3~-可诱导较高的酶活性,这时6-BA 的促进作用也较强。无光照时,NO_3~-只能诱导黄化叶片产生很低的酶活性,这时6-BA 的促进作用也很弱。在1—2小时的诱导期内,环己酰亚胺抑制酶的诱导。结果表明细胞分裂素对酶诱导的促进作用不仅与 NO_3~-的存在有关,还与 NO_3~-诱导硝酸还原酶的必要条件有关,即依赖于酶的诱导过程。     

水稻叶片硝酸还原酶mRNA的体外翻译

水稻叶片总RNA经Oligo(dT)—Cellulose柱层析分离Poly(A)~+RNA。在往层析中采用变温洗脱的方法,可减少rRNA的混杂,提高mRNA的纯度和体外翻译活力。它对麦胚无细胞系统蛋白质合成的促进可稳定在10倍,有时高达20多倍。NR—mRNA的体外翻译产物可用以NR为载体的火箭免疫电泳方法进行鉴定,其量可用火箭峰内的放射强度来表示。     

高等植物叶片中的硝酸还原酶活性稳定因子

从小麦、油菜、浮萍、番茄、烟草的叶片中分离得到NR-SF。不同植物材料中NR及NR-SF能起交叉反应;不同NR-SF影响NR酶动力学性质相同;不同NR-SF的凝胶电泳谱带显示蛋白和糖蛋白性质。NR-SF广泛存在于植物细胞中。     

大豆Bragg结瘤突变系叶片的NR活性调节

大豆（Ｇｌｙｃｉｎｅ ｍ ａｘ （Ｌ．） Ｍｅｒｒ．）Ｂｒａｇｇ 及它的突变体， 超结瘤大豆ｎｔｓ ３８２ 和不结瘤大豆Ｎｏｄ ４９ 的叶片提取物中含有抑制ｉＮＲ活性、ｃ１ＮＲ活性和Ｃ２ＮＲ活性的抑制成分。３００ μＥ·ｍ － ２·ｓ－ １照度和接种根瘤菌ｓｔｒａｉｎ ＵＳＤＡ１１０ 是形成抑制成分的重要条件。在两种条件下，Ｎｏｄ ４９ 中的抑制活性最强， ｎｔｓ ３８２ 的最弱， Ｂｒａｇｇ 的居中。Ｂｒａｇｇ 的接种根提取物对３ 种ＮＲ活性的抑制作用基本同于其叶片提取物； ｎｔｓ ３８２ 的接种根提取物也同于其叶片提取物，基本不抑制ＮＲ的活性， 但Ｎｏｄ ４９ 的接种根提取物只抑制叶片的ｃ２ＮＲ活性， 不同于其叶片提取物抑制３ 种ＮＲ活性的作用。结果说明叶片与根两种提取物在抑制叶片ＮＲ活性的成分上相关     

NITRATE REDUCTASE IN PHOTOSYNTHETIC BACTERIUM, RHODOSPIRILLUM RUBRUM. ADAPTIVE FORMATION OF NITRATE REDUCTASE

1. A method was discovered for adapting the cells of Rhodospirillumrubrum to grow on a nitrate medium, a capacity initially lackingin the organism. The adapted cells were able to grow with nitrateas the sole source of nitrogen. The growth responses of theadapted cells towards various nitrogenous sources were investigatedunder various conditions of incubation (aero- and anaerobiosis,light and dark).
2. The adapted cells were found to have simultaneouslyacquiredthe capacity for reducing nitrite and hydroxylamineas wellas nitrate. The path of nitrogen in the adapted cellswas assumedto be as follows: NO₃^– NO₂^– NH₂OH CellularNitrogen.
3. Nitrate metabolism of the adapted cells was investigatedundervarious conditions. In the light, nitrate was reducedand furtherassimilated, leaving insignificant amounts of nitritein themedium. In this case, consumption of nitrate was markedlyinhibitedby other forms of nitrogen (e.g., nitrite, hydroxylamine,aminoacids and ammonium salts). In the dark, nitrate was reducedas the terminal hydrogen acceptor in the oxidative breakdownof organic substances (e.g., malate) in the medium (i.e., nitraterespiration). More nitrite was accumulated in this case thanin the light. Molecular oxygen inhibited the reduction of, aswell as the growth on, nitrate in any of the above cases.
4. Theeffects on the rate of nitrate reduction (and respiratoryoxygenuptake) caused by various experimental factors (pH, nitrateconcentration, electron donors, and addition of hydroxylamine)were investigated, using the resting cells of the adapted organism.

¹ This paper was submitted to the University of Tokyo to fulfillthe requirement for the author's doctorate. ² Present Address: Botanical Institute, Kyoto University, Sakyo-ku,Kyoto. (Received February 14, 1963; )     

NITRATE REDUCTASE IN PHOTOSYNTHETIC BACTERIUM, RHODOSPIRILLUM RUBRUM. PURIFICATION AND PROPERTIES OF NITRATE REDUCTASE IN NITRATE-ADAPTED CELLS

1. From nitrate-adapted cells of Rhodospirillum rubrum, an activepreparation of nitrate reducing enzyme was isolated in partiallypurified state. The enzyme was found to be localized in thechromatophores of the cell and, on sonication, readily releasedinto the upernatant fraction. The purified enzyme, catalyzingthe electron transfer between DPNH and nitrate, contained ab-type cytochrome, flavin and non-heme iron, which was removedon dialysis in the presence of cyanide. Besides DPNH, only methylviologen(reduced form) was effective as electron donor. 2. The effects of pH and the addition of various activatorsand inhibitors on the rate of nitrate reduction were investigated,using DPNH or reduced methylviologen as the electron donor.The oxidation-reduction of the flavin and the heme in the enzymewas followed spectrophotometrically. A pathway of electron inthe nitrate reduction through this enzyme was proposed. 3. The nitrate reductase of this bacterium was compared withother nitrate reductases obtained from other sources, and themetabolic roles of this enzyme were discussed. In the nitrate-adaptedcells of Rsp. rubrum, only one and the same enzyme was obtainedunder different growth conditions of nitrate assimilation (i.e., nitrate as N-source; light as energy source) and nitrate-respiration(i. e., in the dark; nitrate as hydrogen acceptor and N-source). ¹ Dedicated to Prof. H. TAMIYA on the occasion of his 60th birthday.This paper was submitted to the University of Tokyo to fulfillthe requirement for the author's doctorate. ² Present address; Botanical Institute, Kyoto University. (Received December 14, 1962; )     

钙对黄瓜子叶愈伤组织中硝酸还原酶(NR)活性的影响

本文采用黄瓜子叶愈伤组织,研究了不同钙培养下,对愈伤组织生长、硝酸盐吸收,NR活性以及组织中钙、镁含量的影响。结果表明,缺钙后,愈伤组织生长、硝酸盐吸收、NR活性等都比正常钙培养下的愈伤组织降低。这与用整株植物所得结果基本一致,对此结果进行了讨论。     

串珠镰孢霉硝酸盐还原途径酶的遗传研究*

通过对菌株突变体有性杂交后代的检测方法,对串珠镰孢霉Fusariummoniliforme氮代谢过程中硝酸盐还原途径相关酶基因间关系进行研究。串珠镰孢霉含钼协同因子突变体缺陷型(nitB)与亚硝酸盐还原酶缺陷型突变体(nitC)间的杂交结果显示,在不同的交配群以及在相同交配群不同寄主上的分离菌株中,控制这两种酶的基因有两种类型,并据此提出细胞核基因和细胞质基因共同调控硝酸盐还原途径酶的假说。当杂交后代出现四种表型(nitD:nitB:nitC:wt=1:1:1:1)时,表明这两种酶的遗传受核基因调控,分离时两种基因自由组合;当杂交后代仅有两种表型时,表现为父本表型隐藏,双基因缺陷型(表型同主氮调节基因缺陷型nitD)表型不出现,即母本表现型:野生型为1:1,表明这种遗传类型除受核基因的控制外,还存在细胞质基因的影响。     

大麦幼叶细胞分裂状况和愈伤组织诱导间关系的初步研究(简报)

禾谷类叶片培养迄今还有一定难度,虽然已有再生植株的报告,但效率并不高,基因型间差异也极大。禾谷类叶肉原生质体培养迄今