Instituto de Investigaciones en Biodiversidad y Medio Ambiente (INIBIOMA), Universidad Nacional del Comahue, CONICET, CRUB, San Carlos de Bariloche, Río Negro, Argentina.
Departamento de Física Médica Centro Atómico Bariloche and Instituto Balseiro, CONICET, San Carlos de Bariloche, Río Negro, Argentina.
Sci Rep. 2017 Oct 23;7(1):13837. doi: 10.1038/s41598-017-14085-6.
Circadian systems enable organisms to synchronize their physiology to daily and seasonal environmental changes relying on endogenous pacemakers that oscillate with a period close to 24 h even in the absence of external timing cues. The oscillations are achieved by intracellular transcriptional/translational feedback loops thoroughly characterized for many organisms, but still little is known about the presence and characteristics of circadian clocks in fungi other than Neurospora crassa. We sought to characterize the circadian system of a natural isolate of Aureobasidium pullulans, a cold-adapted yeast bearing great biotechnological potential. A. pullulans formed daily concentric rings that were synchronized by light/dark cycles and were also formed in constant darkness with a period of 24.5 h. Moreover, these rhythms were temperature compensated, as evidenced by experiments conducted at temperatures as low as 10 °C. Finally, the expression of clock-essential genes, frequency, white collar-1, white collar-2 and vivid was confirmed. In summary, our results indicate the existence of a functional circadian clock in A. pullulans, capable of sustaining rhythms at very low temperatures and, based on the presence of conserved clock-gene homologues, suggest a molecular and functional relationship to well-described circadian systems.
生物钟系统使生物能够根据内源性起搏器同步生理机能，这些起搏器的振荡周期接近 24 小时，即使没有外部定时信号也是如此。许多生物的细胞内转录/翻译反馈环已经得到了深入的研究，但是对于除粗糙脉孢菌以外的真菌中生物钟的存在和特征，我们仍然知之甚少。我们试图描述一种天然的出芽短梗霉（Aureobasidium pullulans）的生物钟系统，这是一种具有巨大生物技术潜力的耐冷酵母。出芽短梗霉形成每天的同心环，这些环可以通过光/暗循环同步，也可以在恒定的黑暗中形成，周期为 24.5 小时。此外，这些节律是温度补偿的，这可以通过在低至 10°C 的温度下进行的实验来证明。最后，确认了生物钟必需基因频率、白 collar-1、白 collar-2 和 vivid 的表达。总之，我们的研究结果表明，出芽短梗霉存在一个功能性的生物钟，能够在非常低的温度下维持节律，并且根据保守生物钟基因同源物的存在，表明了与描述良好的生物钟系统的分子和功能关系。
