Fluorescence studies on the molecular action of amphotericin B on susceptible and resistant fungal cells.
Fluorescence studies on the molecular action of amphotericin B on susceptible and resistant fungal cells.
复制标题
两性霉素 B 对敏感和耐药真菌细胞分子作用的荧光研究。
DOI：
10.1021/bi952910c
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发表时间：
1996
期刊：
影响因子：
2.9
通讯作者：
Pieringer,RA
中科院分区：
文献类型：
--
作者：
Haynes,MP;Chong,PL;Buckley,HR;Pieringer,RA
用荧光膜探针TMA-DPH研究了黄曲霉素B（AmB）对AmB敏感和抗性真菌细胞膜的分子作用。AmB是治疗系统性真菌感染的最有效药物，已知其与膜甾醇，特别是麦角甾醇（真菌细胞中的主要甾醇）特异性相互作用。用AmB处理可耐受的白色念珠菌和新型隐球菌细胞，诱导TMA-DPH荧光强度随时间发生新的双相变化。荧光强度的初始降低是由于AmB与TMA-DPH结合时AmB与真菌细胞膜之间的能量转移所致。荧光强度增加的第二阶段被解释为探针重新分配和探针分离的组合，这是由于AmB−麦角甾醇复合物聚集形成膜孔的结果。AmB耐药的新生隐球菌菌株含有94%的异常δ-8双键麦角甾醇前体和仅4%的麦角甾醇（野生型细胞中麦角甾醇为71%），表现出AmB结合的第一阶段，但没有荧光强度增加的第二阶段。这一结果表明，AmB的抗真菌活性在于它能够形成膜孔，由于AmB−麦角甾醇复合物的聚集。AmB诱导的双相荧光强度谱可能导致进一步阐明AmB对真菌细胞的分子作用，并可能提供一种敏感的方法来筛选真菌细胞中的耐药性的发展。
The molecular action of amphotericin B (AmB) on the cell membranes of both AmB-susceptible and AmB-resistant fungal cells was investigated through the use of the fluorescent membrane probe trimethylammonium diphenylhexatriene (TMA-DPH). AmB, the most effective drug for the treatment of systemic fungal infections, is known to interact specifically with membrane sterols, especially ergosterol (the major sterol in fungal cells). Treatment of AmB-susceptibleCandida albicansandCryptococcus neoformanscells with AmB induced a novel biphasic change in TMA-DPH fluorescence intensity over time. The initial decrease in fluorescence intensity results from energy transfer between AmB and TMA-DPH when AmB binds to the fungal cell membrane. The second phase of increasing fluorescence intensity is interpreted in terms of a combination of probe repartitioning and probe segregation as a result of the formation of membrane pores via the aggregation of AmB−ergosterol complexes. An AmB-resistant strain ofC.neoformans,containing 94% of aberrant δ-8 double-bonded ergosterol precursors and only 4% of ergosterol (71% ergosterol in wild-type cells), exhibited the first phase of AmB binding but not the second phase of increasing fluorescence intensity. This result suggests that AmB's antifungal activity lies in its ability to form membrane pores due to aggregation of AmB−ergosterol complexes. The AmB-induced biphasic fluorescence intensity profile may lead to further elucidation of the molecular action of AmB on fungal cells and may provide a sensitive method for screening the development of drug resistance in fungal cells.