ERGOSTEROL BIOSYNTHESIS: A FUNGAL PATHWAY FOR LIFE ON LAND?
ERGOSTEROL BIOSYNTHESIS: A FUNGAL PATHWAY FOR LIFE ON LAND?
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DOI：
10.1111/j.1558-5646.2012.01667.x
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发表时间：
2012-09-01
期刊：
影响因子：
3.3
通讯作者：
Beney, Laurent
中科院分区：
文献类型：
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作者：
Dupont, Sebastien;Lemetais, Guillaume;Beney, Laurent
甾醇是大多数真核细胞的必需脂类，确保重要的结构和信号功能。导致这三个真核生物王国中不同优势甾醇的选择压力仍然未知。在这里，我们研究了麦角甾醇生物合成途径(EBP)不同步骤的进展对酵母菌抵抗从水到气相转变的抗性的影响，这是高等真菌生境的典型扰动。EBP的5个突变株(erg？)和野生型(WT)菌株在EBP中积累了不同的甾醇中间体，并在大气或氮气中干燥和潮湿。结果表明，EBP的进展与酵母耐风干能力的增加是平行的，WT菌株的存活率最高。当在氮气下进行干燥/湿化时，酵母存活率较高，特别是对于EBP的早期突变体。因此，麦角甾醇，通过其对机械和氧化应激的保护作用，可能是由真菌生境中发生的干/湿循环引起的压力所选择的。这些结果支持Bloch假说，该假说假设固醇的性质随着生物合成途径的功能而逐渐优化，并回答了真菌中为什么存在麦角固醇这个长期存在的问题。
Sterols, essential lipids of most eukaryotic cells, ensure important structural and signaling functions. The selection pressure that has led to different dominant sterols in the three eukaryotic kingdoms remains unknown. Here, we investigated the influence of the progression in the different steps of the ergosterol biosynthetic pathway (EBP) on the yeast resistance to transitions from aqueous to aerial media, typical perturbations of the higher fungi habitats. Five mutants of the EBP (erg?), accumulating different sterol intermediates in the EBP, and the wild-type (WT) strain were exposed to drying under atmospheric air or nitrogen and wetting. Results show that the progression in the EBP parallels an increase in the yeast resistance to air-drying with a maximal survival rate for the WT strain. When drying/wetting was performed under nitrogen, yeast survival was higher, particularly for the earlier mutants of the EBP. Thus, ergosterol, through its protective role against mechanical and oxidative stress, might have been selected by the pressure induced by drying/wetting cycles occurring in the fungi habitats. These results support the Bloch hypothesis, which postulates that the properties of sterols are gradually optimized for function along the biosynthetic pathway and provide a response to the enduring question why ergosterol in fungi?.