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本试验对玉米大斑菌致病毒素(Ht—毒素)的产毒条件和毒素的一些特性进行了初步研究。结果表明,玉米大斑菌在25℃黑暗条件下用液体静止培养20d所得的毒素作用最强,在固体培养基质中,以粉碎的玉米碎粒最有利于Ht—毒素的产生(每百克玉米粒可获得Ht—粗毒素1.65g),其次是高粱粒和大米粒。Ht—毒素对热稳定,经煮沸和加热浓缩不会降低其生物活性而且活性还有升高的趋势,但是这种毒素对光却极不稳定,尤其是日光照射后,活性丧失很快。在pH3.0—4.5的偏致性条件下,Ht—毒素可保持活性达20d 以上,而以后随pH 值的升高,活性迅速丧失。
In this experiment, the toxin production conditions and toxins of Streptomyces macrocephala virulent (Ht-toxin) were preliminarily studied. The results showed that T. macrophylla had the strongest effect on the toxins produced by liquid static culture for 20 days at 25 ℃ in darkness. In the solid culture medium, crushed corn kernels were the best for the production of Ht-toxin (per 100 grams of corn 1.65 g of Ht-crude toxin can be obtained), followed by sorghum grains and rice grains. Ht-toxins are thermally stable, boiled and concentrated by heating without diminishing their bioactivity and increasing activity, but the toxins are extremely unstable to light, especially after sun exposure, with loss of activity. Ht-toxin remained viable for more than 20 days under the conditions of pH 3.0-4.5, but then rapidly with the increase of pH.