Bioorganic study on mycoparasitism by Lambertella spp.

苹果果实上的褐腐病菌有时会被角状兰贝氏菌（Lambertella corni-maris）所取代，目前认为这是一种真菌寄生病。这种现象也可以在皮氏培养皿上重现。在这种情况下，每种真菌混合在一起，没有竞争性抑制。但几个月后，我们从培养皿中只观察到角状兰伯氏菌。因此，我们不能仅仅用抗生素的产生来解释这种现象。在PSA培养基上可扩散。虽然在弱酸性条件下是稳定的，但随着pH值的增加，它变得不稳定。我们发现，宿主Monilinia使其周围环境呈酸性以稳定它。因此，Lambertellols可以到达Monilinia区域。降解产物是已知的兰伯胎蛋白，其显示出有效的抗真菌活性，而兰伯胎醇不显示该活性。这可能是真菌替代的机制，而不表现出竞争性抑制。这一机制与蓝氏菌素始终是次要成分的事实相一致。一开始，我们认为有一种机制可以打开anf关闭lambertellin的产生。我们还成功地证明，通过检测其生物降解产物，观察兰伯胎蛋白的持续生产。

Monilinia fructigena is sometimes replaced with Lambertella corni-maris on apple fruits, which is now considers as mycoparasitism. This phenomenon could be reproduced also on Petri dish. In this case each fungus is intermixed together without competitive inhibition. But we observed only Lambertella corni-maris from the dish after a couple of month. Thus we can not explain this phenomenon only with production of antibiotics.Parasite Lambertella produces lambertelllols. These are diffusible on PSA mediu. Although, these are stable under weak acidic conditions, it became labile by increament of pH. We found that the host Monilinia makes its surroundings acidic to stabilize it. So, lambertellols can reach to Monilinia’s area. The degraded product is known lambertellin which shows potent antifungal activity, while lambertellols do not show that activity. It would be the mechanism for the fungal replacement without showing competitive inhibition. This mechanism accorded with that fact that lambertellin is always minor component. In the beginning we thought there is a mechanism to turn on anf off the production of lambertellin. We also succeeded in proving that by observing constant production of lambertellin by detecting its biodegradation product.