四种棉花黄萎病毒素制备方法的比较

多年来大丽轮枝菌毒素的制备过程中常用几种不同的制备方法，究竟不同方法制备的毒素在毒蛋白含量上与致病力上有多大区别，长期以来一直没有定量分析的相关报道。本文就几种常见的方法加以比较，在相同条件下本试验采用的方法四为最佳的试验方法。     

水稻白叶枯病菌毒素对水稻不育系珍汕97A的专化毒性

采用乙酸乙酯法提取对珍汕９７不育胞质具有专化毒性的白叶枯病菌ＡＨ２８、ＧＸ５０和非专化毒性的ＯＳ１４菌株的毒素。以不同浓度的毒素处理珍汕９７不育系和保持系的种子或幼苗,可引起水稻叶片褪绿和细胞坏死,产生与接种病菌相似的症状,在蚕豆叶片上形成过敏性坏死斑;毒素可导致水稻幼苗萎蔫、胚根胚芽生长受抑和根冠细胞死亡;毒素的毒性与毒素浓度和产毒素菌株的致病力成正比;专化性毒素ＡＴ对珍汕９７不育系的毒害程度显著高于对保持系的毒害。     

玉米大斑病菌毒素结构的确定及几种类似物的毒性比较

 通过对玉米大斑病菌Ht-毒素组分1与标准5-羟甲基-2-呋喃甲醛核磁共振¹H谱比较,进一步明确了组分1的化学结构。用玉米离体叶浸渍法及离体根冠细胞致死生测法对Ht-毒素组分1、5-羟甲基-2-呋喃甲醛、呋喃甲醇、呋喃甲醛、呋喃甲酸进行毒性和致病活性比较,结果表明,Ht-毒素组1、标准样品及几种毒素类似物在供试浓度范围内对寄主玉米均有高度的生物毒性,其中以呋喃甲酸毒性最大。从TLC扫描光谱和色谱来看,5-羟甲基-2-呋喃甲醛确为Ht-毒素的一种主要毒性组分,而且该化合物在体内外随着不断氧化,生物毒性逐渐提高。     

松针褐斑病菌毒素对寄主细胞质膜伤害机理的研究

用毒素粗提液处理寄主愈伤组织２ｄ后,可于光学显微镜下观察到严重的细胞原生质泡囊化现象,这是寄主受到毒素作用后于细胞水平所表现出的伤害症状,经毒素诱导后用ＥＳＲ仪检测,寄主愈伤组织于２ｈ内即可产生比对照高得多的超氧阴离子自由基,继而诱发膜脂肪过氧化反应;随着毒素作用时间的延长,寄主细胞膜脂脂肪酸组成发生变化,总的变化趋势为不饱和脂肪酸含量减少,饱和脂肪酸含量增加,毒素作用后于４ｈ以内即可产生大量的Ｍ     

畜禽霉玉米中毒的防治

本文介绍了霉玉米对畜禽生产性能的危害,提出了切实可行的防霉措施、去毒方法和霉玉米中毒的治疗方法。     

五味消毒饮及各味药物对化脓性细菌的抑菌试验与病理模型疗效观察

采用牛津小杯法和攻毒法,观测“五味消毒饮”复方、单味药对化脓性细菌的抑菌效果,及对兔热毒性病理模型的疗效。结果表明：“五味消毒饮”复方、单味药对三种化脓性细菌均有不同程度的抑制作用;复方针剂的抑菌效果优于水煎剂。进一步验证“五味消毒饮”治疗疮痛肿毒的作用。     

Study on Cerospora sojina Hara Toxin Resistance and It‘s Inheritance in Soybean

Cerospora sojina Hara. toxin produced by mycelia of the pathogen can harm soybean plants.In this paper, 50 varieties and one resistant-susceptible combination were used to study the toxin resistance and it‘s inheritance. Comparing the results from the field under different inoculation conditions, the average coincidence rate of the toxin test is 62.37%. The inheritance of resistance to the toxin of Race 7 of Cerospora sojina Hara was proved to be controlled by a pair of single dominant genes. The toxin appraisal method can be used for many purposes owing to it‘s convenience.     

茄子黄萎病菌毒素对茄子体内几种酶活性的影响

以不同抗病性品种的茄子幼苗为试材，研究了茄子黄萎病菌毒素对其叶片POD，PAL及PPO活性变化的影响。结果表明：抗、感病品种茄子幼苗用毒素处理后，POD，PAL，PPO活性均比未处理的对照有所提高，且随处理时间延长，其活性变化呈先升高，后降低趋势，即POD活性在处理后0—24h逐渐升高，之后下降，PPO和PAL活性在处理后0—36h升高，而后活性下降。随毒素浓度增加，POD，PAL，PPO活性变化也呈先升高后降低趋势。3种酶活性与品种抗病性呈正相关关系。     

Screening of Toxin Mutant of Dickeya zeae and Its Biological Characters

[Objective] This study aimed to screen toxin mutant of Dickeya zeae （Er- winia chrysanthemi pv. zeae） and investigate its biological characters. [Method] We obtained a toxin mutant strain D. zeae Ech7-3-42 by using acridine orange as a mutagenic agent and compared their biological characteristics and virulence between the toxin mutant and wild strain. [Result] There was no significant difference in pectin lyase, protease, cellulase and the production of extracellular polysaccharide and lipopolysaccharide, but significant difference in toxin biological activities and vir- ulence. Ech7-3-42 mutant did not produce toxin, as well as the loss of virulence on rice and HR on tobacco, but did not lose the ability to soft rot on potato. Mutant strain Ech7-3-42 can infect rice root and then enriched in the root neck and stalk, but it could not cause rice foot rot. Dickeya zeae （wild and mutant strain） could be detected by PCR in the root neck and below the 1-2 cm long stem area, but could not be detected in the leaves. [Conclusion] We believed that toxin may be one of the important factors for D. zeae virulence on rice.