Fumio Kawai

Micropropagation of Passion fruit from Subcultured Multiple Shoot Primordia

Summary A technique for long-term micropropagation of Passiflora edulis from subcultured multiple shoot primordia is described. Excised tissues from leaves cultured on Murashige and Skoog medium (MS medium) supplemented with 3 % (w/v) sucrose, 1 μmol L -1 6-benzylaminopurine (BA) and 1 μmol L -1 indole-3-butyric acid (IBA) formed multiple shoot primordia. These shoot primordia were transferred to a medium containing 10 μM BA and subcultured repeatedly at 3-week intervals. When subcultured shoot primordia were transferred to a medium containing lower concentrations (0.1 or 1.0 μmol L -1 ) of BA, shoots were formed. Subcultured shoot primordia have continued to regenerate plants for more than 3 years. Shoots developed and rooted on MS medium lacking growth regulators. Rooted plants were transferred to pots and grown in a greenhouse. According to the morphology of leaves of regenerated plants, rejuvenation was obtained by this method of in vitro culture.

Effect of Chlorophenol Analogues on the Oxidative Phosphorylation in Rat Liver Mitochondria

The inhibition of chlorophenol analogues on oxidative phosphorylation in rat liver mitochondria was studied using polarographic technique and some new findings that not only pentachlorophenol (PCP) but also other analogues inhibited the oxidative phoshorylation in a similar manner were made. The inhibitory activity was found to be roughly correlated with its dissociation constant of the inhibitor, PCP being the strongest, varying with the number and position of chlorine atoms in the molecule. The mode of the inhibition was classified into three types and discussed in detail.

Effects of moderate hypercapnia on hypothermia induced by cold He-O2 in rats.

1. Effects of moderate hypercapnia (10% CO2) on rectal temperature, oxygen consumption and body weight loss were examined during and after acute hypothermia induced by cold and helium-oxygen. 2. Hypothermia induction time was reduced significantly by hypercapnia. Rewarming tended to be faster in hypercapnic animals than in normocapnic animals. 3. Hypercapnia significantly reduced body weight loss when measured during hypothermia and during normothermia after rewarming. 4. Oxygen consumption during cooling was decreased by hypercapnia. 5. Exposure to 10% CO2 during cooling may spare energy substrate and favor survival in hypothermia.

Characterization of polypeptides in cultured rice cells differing in cryoprotectability

Summary The polypeptides in high cryoprotectable rice ( Oryza sativa L. cv. Nipponbare) callus cells were characterized by two dimensional polyacrylamide gel electrophoresis (PAGE) analysis and compared with those in low cryoprotectable callus cells. The most prominent change among the observed polypeptides was a 30-kD polypeptide with pI 5.4 (P1), which was abundant in low cryoprotectable cells and scarce in high cryoprotectable cells. Changes in the abundance of this polypeptide during culture correlated with the changes of cryoprotectability of high cryoprotectable cells. Analysis of protoplast polypeptides suggested that this P1 polypeptide was localized mainly in the cell-wall fraction. Microsequencing analysis revealed that the N -terminal amino acid sequence (the first 29 residues) of the polypeptide was 48% identical to that of a polypeptide found in cultured tobacco cells.

[158] Assay methods, isolation procedures, and catalytic properties of riboflavin synthetase from spinach

Publisher Summary This chapter discusses the assay methods, isolation procedures, and catalytic properties of riboflavin synthetase from spinach. The conversion catalyzed by riboflavin synthetase, four carbon atoms from the methyl group substituents and carbons 6 and 7 of one molecule of 6, 7-dimethyl–8-ribityllumazine are transferred to a second molecule of the lumazine to form the o-xylene ring of riboflavin. This mechanism is established both by the stoichiometry of the reaction and by the isotopic studies. Riboflavin synthetase activity is detected in extracts of a number of plants and flavinogenic microorganisms and is found in homogenates of some animal livers. Partial purification of the enzyme is performed with spinach, Escherichia coli , and Ashbya gossypii . 6, 7-Dimethyl-8-ribityllumazine is mixed with the enzyme and the riboflavin produced is measured spectrophotometrically by reading absorbancies at 470 and 405 nm, or fluorophotometrically after isolation by paper chromatography. The purification procedure for spinach enzyme is carried in seven different steps, namely––extraction, first and second ammonium sulfate fractionation, protamine sulfate treatment, CM-cellulose treatment, and first and second diethylaminoethyl (DEAE)-cellulose column chromatography.

Inhibitory Effect of Jasmonic Acid on Gametophytic Growth, Initiation and Development of Sporophytic Shoots in Equisetum arvense

Summary An in vitro culture system of Equisetum arvense L. was used to analyze the effects of jasmonic acid (JA) on gametophytic growth and initiation and development of sporophytic shoots. The growth of gametophytic and sporophytic tissues was inhibited by JA if the culture medium contained permanently this growth regulator; preincubation of these tissues with JA and subsequent cultivation on a JA-free medium were nearly inefficient. JA inhibited effectively the initiation of sporophytic shoots, if applied simultaneously with cytokinin (benzyl adenine), which is absolutely required for this initiation process. The interaction between JA and cytokinin in sporophytic shoot initiation in E. arvense may be an important control for the regulation of this physiological process.

Influence of the Herbicide Oryzalin on the Sporophytic Morphogenesis of Equisetum arvense

Summary Sporophytic shoot primordia are initiated on gametophyte tissue of Equisetum arvense when cultured in a medium supplemented with cytokinin. The initiated shoots can develop on a cytokinin-free medium. Oryzalin, a dinitroaniline herbicide, inhibited the initiation and development of sporophytic shoots. But gametophytic growth with normal morphogenesis was not inhibited by oryzalin. These results suggest that some alteration induced by oryzalin is fatal to sporophytic, but not to gametophytic morphogenesis. Histological features in relation to the inhibition of sporophytic morphogenesis by oryzalin are discussed.

Studies on Protein Foods (Part 1)

乾燥トルラ酵母よりタンパク質の分離抽出法を検索した。その結果1) 水, 温水, 中性塩類溶液ではタンパク質はほとんど抽出できない。2) 0.5%以上のアルカリ溶液はタンパク質をよく抽出し得る。アルカリ濃度の上昇, あるいは抽出時間の延長は抽出率を高め得るが, タンパク質の加水分解を促進し, 製品の着色が著しい。3) セルラーゼによる酵素処理, ことに低濃度のアルカリ抽出との併用は, タンパク質抽出法として比較的推奨し得る。4) 8～10Mの尿素溶液による抽出は, 収量も良く, 操作も簡易で, 且つタンパク質の加水分解を伴わず優れた方法であることを立証し得た。5) 尿素抽出方法による精製タンパク質は, 無臭でほとんど白色に近く, 窒素含量12.8%でほとんど純タンパク質に近い。ペプシン, トリプシンによる消化率も92%以上であった。

Polarographic Determination of Respiratory Activity with Clark Oxygen Electrode

The authors have developed a polarographic technique in which Clark oxygen electrode (stationary platinum electrode covered with a polyethylene membrane) is employed for the determination of respiratory activity. The procedure of the operation is very simple, yet it was highly sensitive to the changes of the oxygen concentration in the solution, and the value of current was proportional to the oxygen concentration. The respiratory activity and control of rat liver mitochondria could be determined satisfactorily by this method.

Changes of Qualities in Rice during Storage

プラスチック積層フィルムで包装した米穀類 (籾, 玄米, 精白米) を約9℃～13℃の水中に保存し, 梅雨期, 夏期, 冬期を経過した時点でその品質変化の程度を種々の化学成分含量および生物活性変化の様相, ならびに物性試験, 食味試験などによって調査した。その結果,(1) 積層フィルムによる水遮断性は完全であり, 1カ年間を通じての水分変化は0.3～0.5%増であった。(2) 脂肪, でんぷん質, タンパク質, 有機酸, ビタミンB1など種々の化学成分変化は極めて緩徐で, 従来の低温倉庫での保存と同等の効果を示した。(3) 水中貯蔵米の発芽率, カタラーゼ活度, パーオキシダーゼ活度などの生物活性は1カ年後においてもほとんど失われなかった。(4) 古米臭の指標としての揮発性カルボニル化合物, 炊飯特性, テクスチャーなどの測定結果は古米化の進行が水中区では非常に緩徐であることを示している。(5) 7カ月貯蔵後の精白米について行なった食味試験の結果, 水中区は外観, 香り, うま味, 粘り, 硬さ, 綜合評価のすべてにおいて基準の低温米とほとんど差がないと判定された。(6) CO2ガス封入区は脂肪およびビタミンB1含量変化の防止, パーオキシダーゼ活性の保持, 古米化の速度低下など多くの点でair区よりも優れていた。以上, 水中での密封低温貯蔵法による米穀類の品質変化は極めて緩徐で, 従来の低温倉庫に管理されている状態と同等の効果のあることが確認された。なお同一試料を引続き水中に貯蔵し経時的に品質変化を追跡中で, その結果は次報で報告する。