Intracellular pH homeostasis plays a role in the tolerance of Debaryomyces hansenii and Candida zeylanoides to acidified nitrite
Intracellular pH homeostasis plays a role in the tolerance of Debaryomyces hansenii and Candida zeylanoides to acidified nitrite
复制标题
DOI：
10.1128/aem.00571-08
复制
发表时间：
2008-08-01
影响因子：
4.4
通讯作者：
Arneborg, Nils
中科院分区：
文献类型：
--
作者：
Mortensen, Henrik Dam;Jacobsen, Tomas;Arneborg, Nils
研究了酸化亚硝酸盐胁迫对汉逊德巴利酵母（Debaryomyces hansenii）和类泽氏假丝酵母（Candida zeylanoides）单细胞生长启动和细胞内pH（pH（i））的影响。结果表明，200 μ g/ml的亚硝酸盐引起了明显的生长抑制和细胞内酸化。hansenii在外部pH（pH（ex））值为4.5时，但在pH（ex）为5.5时不发生。这些结果表明，亚硝酸本身在酸化亚硝酸盐的抗真菌作用中起着重要作用。此外，两种酵母菌都经历了严重的生长抑制和pH（ex）4.5时的pH（i）降低，表明酸化亚硝酸盐的至少一些抗真菌作用可能是由于细胞内酸化。梭zeylanoides，这一现象可以部分地解释为从生长中产生能量的解偶联效应。汉逊德巴利酵母是更宽容的酸化亚硝酸盐在pH值（前）5.5比C zeylanoides，作为确定的增长启动的速度。结合D. hansenii能够在pH（ex）5.5时维持pH（i）稳态，而Zeylanoides则不能，我们的研究结果表明维持pH（i）稳态的能力在D. hansenii和C. zeylanoides。研究了两种酵母在酸化-亚硝酸盐胁迫期间维持pH（i）稳态的不同能力的可能机制，包括细胞内缓冲能力和质膜ATP酶活性，但这些机制都不能解释这种差异。
The effects of acidified-nitrite stress on the growth initiation and intracellular pH (pH(i)) of individual cells of Debaryomyces hansenii and Candida zeylanoides were investigated. Our results show that 200 mu g/ml of nitrite caused pronounced growth inhibition and intracellular acidification of D. hansenii at an external pH (pH(ex)) value of 4.5 but did not at pH(ex) 5.5. These results indicate that nitrous acid as such plays an important role in the antifungal effect of acidified nitrite. Furthermore, both yeast species experienced severe growth inhibition and a pH(i) decrease at pH(ex) 4.5, suggesting that at least some of the antifungal effects of acidified nitrite may be due to intracellular acidification. For C. zeylanoides, this phenomenon could be explained in part by the uncoupling effect of energy generation from growth. Debaryomyces hansenii was more tolerant to acidified nitrite at pH(ex) 5.5 than C zeylanoides, as determined by the rate of growth initiation. In combination with the fact that D. hansenii was able to maintain pH(i) homeostasis at pH(ex) 5.5 but C zeylanoides was not, our results suggest that the ability to maintain pHi homeostasis plays a role in the acidified-nitrite tolerance of D. hansenii and C. zeylanoides. Possible mechanisms underlying the different abilities of the two yeast species to maintain their pH(i) homeostasis during acidified-nitrite stress, comprising the intracellular buffer capacity and the plasma membrane ATPase activity, were investigated, but none of these mechanisms could explain the difference.