摘要
生长阶段和冲击阶段均添加3.5mmol/LMg2+能显著提高融合株SPSC在20%(体积分数)酒精冲击下的存活率:经过9h冲击,对照组的存活率为0,而添加Mg2+试验组的存活率为53.1%,表明适当浓度的Mg2+能显著提高菌体的耐酒精能力.通过考察Mg2+对菌体在15%(体积分数)酒精冲击下细胞膜透性的影响发现,生长阶段和冲击阶段均添加3.5mmol/LMg2+的试验组的胞外核苷酸平衡浓度和细胞膜透性系数(P′)分别仅为对照组水平的45.6%和15.6%,表明添加适当浓度的Mg2+能显著降低受冲击菌体的细胞膜透性;而且,添加Mg2+提高存活率与添加Mg2+降低胞外核苷酸浓度和P′存在直接的对应关系.因此,Mg2+提高融合株SPSC耐酒精能力是与其降低受冲击菌体细胞膜透性密切相关的.
Mg^(2+) (as MgSO_4) at 3.5 mmol/L remarkably increased ethanol tolerance of fusant SPSC. After 9 h of exposure to 20% (volume fraction) ethanol at 30 ℃, no viability remained for the control whereas 53.1% remained for the cells both grown and incubated in Mg^(2+)-added medium. To gain insight into the way that Mg^(2+) promoted ethanol endurance of this strain, the experiment was carried out to test the influence of Mg^(2+) on plasma membrane permeability of yeast cells subjected to 15% (volume fraction) ethanol at 30 ℃. It was found that the equilibrium nucleotide concentration and plasma membrane permeability coefficient (P′) of the cells both grown and incubated in Mg^(2+)-added medium accounted for only 45.6 % and 15.6 % those of the control respectively, which indicates that adding Mg^(2+) can markedly decrease plasma membrane permeability of yeast cells subjected to ethanol stress. Moreover, the enhancing effect of Mg^(2+) on viability precisely corresponds to the striking reductions in extracellular nucleotide concentration and P′ by supplementing Mg^(2+). Thus, that Mg^(2+) enhances ethanol tolerance of this strain is closely related to its capability to reduce plasma membrane permeability of yeast cells under ethanol stress.
出处
《大连理工大学学报》
EI
CAS
CSCD
北大核心
2004年第2期228-232,共5页
Journal of Dalian University of Technology
基金
国家"863"高科技研究发展计划项目(2002AA647060).
