Nurudeen T A, Ahearn D G
J Clin Microbiol. 1979 Nov;10(5):724-9. doi: 10.1128/jcm.10.5.724-729.1979.
Species of Filobasidiella, the agents of cryptococcosis, produced melanin-like pigments within 4 to 48 h with diphenol, aminophenol, and diaminobenzene compounds as substrates. The rate of phenyloxidase activity was found to be regulated by glucose and nitrogen catabolite repression. Increased glucose concentration reduced pigmentation of all serotypes of Filobasidiella, whereas repression by nitrogen sources varied with the strain. Glutamine repressed the phenyloxidases of all isolates except those of serotype B, and (NH4)2SO4 repressed the phenyloxidase of all isolates except that of serotype A. Tyrosine and glycine appeared to be near optimal for phenyloxidase activity but not necessarily for growth of all strain examined. Representatives of serotype C were unique in that their phenyloxidase system was adpative in contrast to the constitutive system found in the other serotypes. No single medium was found to support pigmentation of all strains of Cryptococcus neoformans within a 72-h incubation period; false-negative reactions can occur.
新型隐球菌病的病原体丝状担子菌属，以二酚、氨基酚和二氨基苯化合物为底物，在4至48小时内产生黑色素样色素。发现苯氧化酶活性速率受葡萄糖和氮分解代谢物阻遏的调节。葡萄糖浓度增加会降低丝状担子菌所有血清型的色素沉着，而氮源的阻遏作用因菌株而异。谷氨酰胺抑制除B血清型外所有分离株的苯氧化酶，硫酸铵抑制除A血清型外所有分离株的苯氧化酶。酪氨酸和甘氨酸似乎对苯氧化酶活性接近最佳，但不一定对所有检测菌株的生长最佳。C血清型的代表菌株独特之处在于，与其他血清型中发现的组成型系统相比，其苯氧化酶系统具有适应性。在72小时的培养期内，未发现单一培养基能支持所有新型隐球菌菌株的色素沉着；可能会出现假阴性反应。
