白色念珠菌分泌型酸性蛋白酶的诱导研究

Studies on induction of secretory acid proteinase in candida albicans

目的 了解诱导白色念珠菌分泌酸性蛋白酶 (SAP)的条件。方法 分别用含不同氮源及不同起始pH的培养基摇瓶培养白色念珠菌WD 2 7菌株 ,定时取样用分光光度法检测胞外SAP活性和菌体生长量。结果 蛋白质、多肽类大分子氮源可诱导白色念珠菌分泌SAP ,氨基酸、尿素、铵盐等小分子、易代谢氮源可阻遏SAP分泌。当两大类氮源同时存在时酶分泌抑制程度取决于阻遏物的浓度。培养基起始pH为 3 0～ 6 0时白色念珠菌才可被诱导分泌SAP。

Objectvie To find out the conditions required for induction of secretory acid proteinase (SAP) by candida albicans.Methods SAP activity and growth mass was monitored periodically by spectrophotometric assay when candida albicans was incubated in a medium with different nitrogen source and with varied starting pH,respectively.Results Proteins and peptides supplied as nitrogen sources could induce SAP,whereas low Mw nitrogen sources such as amino acids,urea and ammonium salts repressed SAP production.When high Mw and low Mw nitrogen supplies were present simultaneously in media,the inhibition extent of SAP secretion was determined by repressor concentration.SAP induction could be observed only at initial pH 3.0～6.0 in BSA-MM.Conclusions Induction level of SAP in candida albicans was affected mainly by molecular mass of a nitrogen source and pH value in environment.