脱乙酰几丁质的制备及其对细胞透性和脱乙酰几丁酶活性的影响

The Preparation of Chitosan and its Effect on the Cell Permeability and Chitosanase Activity

虾壳经盐酸和氢氧化钠处理，高锰酸钾漂白，制得几丁质，几丁质经５０％ＮａＯＨ处理，获得脱乙酰几丁质，制得的脱乙酰几丁质能溶于３％醋酸中。植物离体叶片经不同浓度脱乙酰几丁质处理，用电导法和染料结合法，分别测定细胞中电解质和蛋白质的外渗量，用分光光度法测定脱乙酰几丁酶的活性。结果表明，脱乙酰几丁质能使多种植物电解质的外渗量增加，脱乙酰几丁质的浓度愈大，处理的时间愈长，则外渗量增加愈显著。易染赤霉病的小麦品种比抗赤霉病的小麦品种，叶片电解质的外渗量增加。外渗量的增加与脱乙酰几丁质的浓度及处理的时间有关。叶片中蛋白质的外渗与电解质的外渗情况相似，易染病的品种比抗病的品种，蛋白质的外渗量增加７０％－８０％。脱乙酰几丁质处理，使抗病品种叶片中脱乙酰几丁酶的活性增加４０％－６０％。在同样条件下，不抗病品种酶的活性变化不大。文中对所得结果与植物抗病性之间的关系进行了讨论。

Chitin was prepared from shrimp shells by treatment with hydrochloric acid and sodium hydroxide, and was given a further bleaching with KMnO4. Chitosan was prepared from chitin by heating it at 115℃ in 50% NaOH for 20hr until the product could be dissolved in 3% acetic acid. Treatment of excised leaves with chitosan of different concentration increased the permeability of cell membranes as the result showed by the leakage of electrolytes and proteins into the medium. The activity of chitosanase was determined by spectrophotometric method. The results showed that the treatment increase the leakage amount of electrolytes of several plants. In the experiment, two varieties of wheat were used. One was resistant to scab while the other was susceptible to this disease. As a result, the leakage amount of the susceptible variety was larger than that of the resistant one. Furthermore, the amount of leakage was in relation to the concentration of chitosan and time of treatment. The higher the concentration was and the longer the materials were treated, the more striking increase would get.As far as protein leakage was concerned, a similiar result was got. The protein leakage amount of the leaves of the variety susceptible to scab increased by 70%-80% over that of resistant one, while chitosanase activity of treated leaves of the resistant variety increased by 40-60% over that of the susceptible one. On the same condition, the chitosanase activity of the susceptible one had no change or changed little. The relation between the results of this paper and the disease-resistance of plant was also discussed.