Palhano F L, Gomes H L, Orlando M T D, Kurtenbach E, Fernandes P M B
Departamento de Ciências Fisiológicas, Universidade Federal do Espírito Santo, Av. Marechal Campos, Vitória, ES, Brazil.
Cell Mol Biol (Noisy-le-grand). 2004 Jun;50(4):447-57.
Yeasts are unicellular organisms that are exposed to a highly variable environment, concerning the availability of nutrients, temperature, pH, radiation, access to oxygen and, specially, water activity. Evolution has selected yeasts to tolerate, to a certain extent, these environmental stresses. High hydrostatic pressure (HHP) exerts a broad effect upon yeast cells, interfering with the cell membranes, cellular architecture and in processes ofpolymerisation and denaturation of proteins. Gene expression patterns in response to HHP revealed a stress response profile. The majority of the upregulated genes were involved in stress defence and carbohydrate metabolism while most of the repressed ones were in cell cycle progression and protein synthesis categories. In addition, in the present work it was seen that mild pressure induced cell cycle arrest and protection against severe stresses, such as high temperature, high pressure and ultra cold shock. Nevertheless, this protection was only significant if the cells were incubated at atmospheric pressure after the HHP treatment. Expression of genes that were upregulated by HHP and are related to resistance to this stresses were also analyzed, and, for the majority of them, higher induction was attained after 15 min post-pressurization. Taken together, the results imply an interconnection among stresses.
酵母是单细胞生物，它们所面临的环境高度多变，涉及营养物质的可利用性、温度、pH值、辐射、氧气供应，特别是水分活度。进化过程使酵母在一定程度上能够耐受这些环境压力。高静水压（HHP）对酵母细胞有广泛影响，会干扰细胞膜、细胞结构以及蛋白质的聚合和变性过程。响应HHP的基因表达模式揭示了一种应激反应特征。大多数上调基因参与应激防御和碳水化合物代谢，而大多数受抑制基因则属于细胞周期进程和蛋白质合成类别。此外，在本研究中还发现，轻度压力会诱导细胞周期停滞，并提供针对高温、高压和超低温休克等严重应激的保护作用。然而，这种保护作用只有在HHP处理后将细胞置于常压下培养时才显著。还分析了受HHP上调且与抗这种应激相关的基因的表达情况，对于大多数此类基因，在加压后15分钟诱导程度更高。综上所述，这些结果表明不同应激之间存在相互联系。
