Hiromu Yoshii

On the Isolation Procedure of Ribonucleic Acid from Rice Plant

本報告は,高等植物特に水稲より比較的簡単に,短時間で,しかも僅少な材料より,かなり高純度のリボ核酸(RNA)を分離調整する方法について考察したものである.供試した水稲核酸はその理化学的諸性質を,酵母核酸を対照として観察したが,要約すると次のとおりである. (1) 水稲葉4gより核酸10mgを得.収量は約1/400である. (2) 糖成分にはリボーズが確証でき,紫外部の吸収特性は,極大吸収が258mμ,極小吸収が230mμでEMax.2581cm/EMin.2301cm=1.8～2.5である. (3) NIP率は1.64～1.65で核酸の理論値に極めて近い値である. (4) 塩基には,アデニン,グアニン,シトシンおよびウラシルが確認でき,またアルカリ分解物の電泳結果より,アデニル酸,グアニル酸,シチジル酸およびウリジル酸が確認できる.そして各ヌクレオチドのモル比百分率は,よく酵母核酸と類似している. (5) 蛋白質は含まれていない.ただ低級なグルコーザン様物質が少量含まれているが,これはメトキシエタノール(CH3OCH2CH2OH)で十分に処理する事により著しく除去する事が出来る. 以上の諸性質からみて本法により水稲葉から抽出出来る核酸はリボ核酸(RNA)であると言える.

Comparison of the Reactions of Rice and Wheat Seedlings to Infection of the Causal Fungus of the "Bakanae" Disease and to Filtrates of its Cultures

The occurrence of physiologic specialization in the causal fungus of the “Bakanae” disease of rice has already been observed by several authors. Certain strains of the fungus have the power to cause strongly the overgrowth of rice seedlings, while some others check their growth. There are undoubtedly some strains which show the intermediate character as to the growth-promotion of the host plant. Moreover, from previous investigations it is clear that the causal fungus isolated from rice seedlings is capable of attacking several other plants and causing their characteristic overgrowth. On the other hand, some investigators have carried out the interesting experiments, showing that the filtrate of cultures of a certain strain of the causal fungus is able to produce the phenomenon characteristic of the “Bakanae” disease in the absence of the mycelium. Consequently, the writer treated the overgrowth property shown by the presence of the causal fungus, distinguishing from the similar property shown by its absence. The latter is called “virulence” in the present paper, as compared with the proper pathogenicity.The present paper deals with the results of the writers investigations carried out in order to solve the following two problems.1. Whether the tendency in the extent of pathogenicity shown by a strain is similar or not to that of virulence shown by the same strain.2. Whether the tendency in the extent of pathogenicity as well as of virulence for other plants is similar or not to that for rice seedlings.From repeated experiments the writer recognized safely the following conclusions.1. Both the pathogenicity and the virulence in the causal fungus of the “Bakanae” disease of rice seedlings are different in their extent according to strains, as has already been reported by the previous investigators.2. The pathogenicity and the virulence shown by a strain have a similar tendency in their extent.3. The data obtained in repeated experiments with wheat seedlings showed that the tendency in the extent of pathogenicity as well as of virulence for that plant seems to be quite parallel to that for rice seedlings.