Plant Physiology and Chemistry Research Unit, Agricultural Research Service, Western Regional Research Center, U.S. Department of Agriculture, Berkeley, California 94710.
Proc Natl Acad Sci U S A. 1983 Jun;80(11):3227-31. doi: 10.1073/pnas.80.11.3227.
When fed 10 ppm of one of the following sterols: cholesterol (cholest-5-en-3beta-ol), wingsterol (21-isopentylcholesterol), desmosterol [cholesta-5,24(25)-dien-3beta-ol], 24-methylenecholesterol [ergosta-5,24(28)-dien-3beta-ol], or fucosterol [stigmasta-5,24(28)-dien-3beta-ol], the pathogenic fungus Phytophthora cactorum, which is naturally unable to epoxidize squalene, accumulated each of the test compounds to similar levels. Fucosterol, the only sterol metabolized, was reduced to yield 24-ethylcholesterol. All the sterols tested induced the formation of sex structures. Fertilization and subsequent maturation of oospores capable of germination occurred only with the naturally occurring sterols. Wingsterol treatments resulted in aborted oospores. None of the sterols tested was inhibitory to growth, measured as changes in the 21-day mycelial dry weight. The results are consistent with the view that the accumulated sterol functions to regulate the life cycle of P. cactorum. However, the metabolism and kinds of recognition of the sterol molecule, in terms of uptake and effects on growth and induction of the various sexual events, contrast sharply with what is known for other oomycetous fungi such as Achlya and Saprolegnia. This implies that the evolutionary histories of the Oomycetes may be different.
当喂食以下固醇中的 10ppm 时：胆固醇（胆甾-5-烯-3β-醇）、翼甾醇（21-异戊基胆固醇）、去甲固醇[胆甾-5,24（25）-二烯-3β-醇]、24-亚甲基胆固醇[麦角甾-5,24（28）-二烯-3β-醇]或褐藻甾醇[豆甾-5,24（28）-二烯-3β-醇]，天然不能环氧化鲨烯的致病真菌胶孢炭疽菌将每种测试化合物积累到相似水平。唯一被代谢的褐藻甾醇被还原为 24-乙基胆固醇。所有测试的固醇都诱导性结构的形成。只有天然固醇才能受精并随后成熟为能够萌发的卵孢子。翼甾醇处理导致卵孢子流产。测试的固醇都没有抑制生长，这可以通过 21 天菌丝干重的变化来衡量。结果与以下观点一致，即积累的固醇可调节胶孢炭疽菌的生命周期。然而，就摄取以及对生长和各种性事件的诱导的影响而言，固醇分子的代谢和种类识别与其他卵菌如 Achlya 和 Saprolegnia 中已知的情况形成鲜明对比。这意味着卵菌的进化历史可能不同。
