Outlines for the definition of halotolerance/halophily in yeasts: Candida versatilis (halophila) CBS4019 as the archetype?
Outlines for the definition of halotolerance/halophily in yeasts: Candida versatilis (halophila) CBS4019 as the archetype?
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DOI：
10.1016/s1567-1356(02)00200-3
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发表时间：
2003-06
影响因子：
3.2
通讯作者：
Magda Silva-Graça;L. Neves;C. Lucas
中科院分区：
文献类型：
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作者：
Magda Silva-Graça;L. Neves;C. Lucas
选择通用念珠菌（嗜盐菌）CBS4019来研究长期暴露于极高盐浓度的生理反应。一般来说，我们的结果显示在应激条件下生长期间酶表达显着增加。尽管甘油和甘露醇途径不受葡萄糖抑制，但它们被发现受到代谢调节。甘油-3P-脱氢酶使用其辅助因子 NADPH 或 NADH，在高盐浓度的生长过程中有利于 NADPH。这种交换辅因子的能力、增加的发酵速率以及观察到的甘露醇途径活性被认为有助于酵母的氧化还原稳定性。酶本身在体外不耐盐。一致的是，细胞内钠含量较低，而生长所需的细胞内钾含量较高。讨论了嗜盐性的概念及其对酵母的适用性。
Candida versatilis(halophila) CBS4019 was chosen to study the physiological reactions of long-term exposure to extremely high salt concentrations. In general, our results show a significant increase in enzyme expression during growth under stress conditions. Although glycerol and mannitol pathways are not under glucose repression, they were found to be metabolically regulated. Glycerol-3P-dehydrogenase used either of its cofactors NADPH or NADH, being in favor of NADPH during growth with high salt concentrations. This ability of interchanging cofactors, an increased fermentation rate, and the observed mannitol pathway activity are suggested to contribute to the yeasts’ redox stability. Enzymes per se were not salt-tolerant in vitro. Consistently, intracellular sodium was low and intracellular potassium, a requirement for growth, was high. The concept of halophily and its applicability to yeasts is discussed.