Eminger M, Gásková D, Brodská B, Holoubek A, Stadler N, Sigler K
Institute of Physics, Charles University, Prague, Czech Republic.
Folia Microbiol (Praha). 1999;44(3):283-8. doi: 10.1007/BF02818548.
The rate and extent of uptake of the fluorescent probe diS-C3(3) reporting on membrane potential in S. cerevisiae is affected by the strain under study, cell-growth phase, starvation and by the concentration of glucose both in the growth medium and in the monitored cell suspension under non-growth conditions. Killer toxin K1 brings about changes in membrane potential. In all types of cells tested, viz. in glucose-supplied stationary or exponential cells of the killer-sensitive strain S6/1 or a conventional strain RXII, or in glucose-free exponential cells of both strains, both active and heat-inactivated toxin slow down the potential-dependent uptake of diS-C3(3) into the cells. This may reflect "clogging" of pores in the cell wall that hinders, but does not prevent, probe passage to the plasma membrane and its equilibration. The clogging effect of heat-inactivated toxin is stronger than that exerted by active toxin. In susceptible cells, i.e. in exponential-phase glucose-supplied cells of the sensitive strain S6/1, this phase of probe uptake retardation is followed by an irreversible red shift in probe fluorescence maximum lambda max indicating damage to membrane integrity and cell permeabilization. A similar fast red shift in lambda max signifying lethal cell damage was found in heat-killed or nystatin-treated cells.
荧光探针diS-C3(3)用于报告酿酒酵母膜电位，其摄取速率和程度受所研究的菌株、细胞生长阶段、饥饿状态以及生长培养基和非生长条件下监测的细胞悬液中葡萄糖浓度的影响。杀伤毒素K1会引起膜电位的变化。在所有测试的细胞类型中，即在供有葡萄糖的静止期或指数期的杀伤敏感菌株S6/1或传统菌株RXII的细胞中，或在两菌株无葡萄糖的指数期细胞中，活性毒素和热灭活毒素均会减缓diS-C3(3)依赖电位的细胞摄取。这可能反映了细胞壁中孔隙的“堵塞”，这种堵塞会阻碍但不会阻止探针进入质膜及其达到平衡。热灭活毒素的堵塞作用比活性毒素更强。在敏感细胞中，即在敏感菌株S6/1指数期供有葡萄糖的细胞中，探针摄取延迟的这个阶段之后是探针荧光最大波长λmax的不可逆红移，这表明膜完整性受损和细胞通透性增加。在热杀死或经制霉菌素处理的细胞中也发现了类似的λmax快速红移，这意味着细胞受到致命损伤。
