Blomberg A
Department of General and Marine Microbiology, University of Göteborg Sweden.
Yeast. 1997 May;13(6):529-39. doi: 10.1002/(SICI)1097-0061(199705)13:6<529::AID-YEA103>3.0.CO;2-H.
Osmotic hypersensitivity is manifested as cellular death at magnitudes of osmotic stress that can support growth. Cellular capacity for survival when plated onto high NaCl media was examined for a number of laboratory and industrial strains of Saccharomyces cerevisiae. During respiro-fermentative growth in rich medium with glucose as energy and carbon source, the hypersensitivity phenomenon was fairly strain invariant with a threshold value of about 1 M-NaCl; most strains fell within a 300 mM range in LD10 values (lethal dose yielding 10% survival). Furthermore, all but one of the strains displayed similar differential death responses above the threshold value, i.e. ten-fold decreased viability for every 250 mM increase in salinity. Addition of small amounts of salt to the growth medium drastically improved tolerance and shifted the hypersensitivity threshold to higher NaCl concentrations. This salt-instigated tolerance could partly be reversed by washing in water. The washing procedure depleted cells of the glycerol that they had accumulated under saline growth, and the contribution from glycerol to the improved tolerance was about 50% in the two strains examined. Growth on derepressing carbon sources like galactose, ethanol or glycerol gave strain-dependent responses. The laboratory strain X2180-1A drastically improved tolerance while the bakers' yeast strain Y41 did so only marginally. It was concluded that all strains of S. cerevisiae display the osmotic hypersensitivity phenomenon in qualitative terms while the quantitative values differ. It was also proposed that growth rate does not dictate the level of osmotic hypersensitivity of S. cerevisiae.
渗透超敏反应表现为在能够支持生长的渗透胁迫强度下细胞死亡。对许多酿酒酵母的实验室菌株和工业菌株，检测了它们接种到高氯化钠培养基上时的细胞存活能力。在以葡萄糖作为能量和碳源的丰富培养基中进行呼吸发酵生长期间，超敏现象在菌株间相当稳定，阈值约为1 M-氯化钠；大多数菌株的LD10值（产生10%存活率的致死剂量）在300 mM范围内。此外，除了一个菌株外，所有菌株在阈值以上均表现出相似的差异死亡反应，即盐度每增加250 mM，活力下降10倍。向生长培养基中添加少量盐可显著提高耐受性，并将超敏阈值转移到更高的氯化钠浓度。这种由盐引发的耐受性可通过水洗部分逆转。水洗过程耗尽了细胞在盐胁迫下积累的甘油，在所检测的两个菌株中，甘油对耐受性提高的贡献约为50%。在半乳糖、乙醇或甘油等解阻遏碳源上生长产生了菌株依赖性反应。实验室菌株X2180-1A的耐受性显著提高，而面包酵母菌株Y41仅略有提高。得出的结论是，所有酿酒酵母菌株在定性方面均表现出渗透超敏现象，而定量值有所不同。还提出生长速率并不决定酿酒酵母的渗透超敏水平。
