Evidence that Streptococcus mutans constructs its membrane with excess fluidity for survival at suboptimal temperatures.
Evidence that Streptococcus mutans constructs its membrane with excess fluidity for survival at suboptimal temperatures.
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有证据表明，变形链球菌构建的膜具有过度的流动性，可以在次优温度下生存。
DOI：
10.1099/00221287-121-1-105
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发表时间：
1980
期刊：
影响因子：
--
通讯作者：
Higgins,ML
中科院分区：
文献类型：
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作者：
Tsien,H;Panos,C;Shockman,GD;Higgins,ML
当来自在37 °C下生长的变形链球菌菌株FA-1的培养物的细胞暴露于26 ℃或更低的温育温度下5分钟或更长时间时，在其冷冻切割的膜的凸起断裂面上观察到广泛的颗粒聚集。颗粒的聚集伴随着生长活化能的平行增加。通过将生长温度从37 °C改变到24 °C以使培养物质量加倍，膜颗粒聚集的转变温度可以从约26 ° C降低到0 °C。虽然膜脂在24 °C下生长期间变得富含不饱和脂肪酸，但这种富集并不伴随着培养物的生长速率增加。然而，在24 °C下的生长期确实导致细菌在10 °C下的生长速度比直接从37 °C下生长的培养物中转移的细菌更快。这些观察结果表明，当细菌在24 °C下生长时发生的膜流动性增加并不允许细菌在24 °C下生长得更快，而是允许它们更容易适应生长温度的进一步降低。
When cells from cultures ofStreptococcus mutansstrain FA-1 grown at 37 °C were exposed to incubation temperatures of 26 C or less for 5 min or more, an extensive aggregation of particles was observed on the convex fracture faces of their freeze-cleaved membranes. Aggregation of particles was accompanied by a parallel increase in the activation energy for growth. By shifting the growth temperature from 37 to 24 °C for one doubling of culture mass, the transition temperature for membrane particle aggregation could be lowered from about 26 to 0 °C. Although membrane lipids became enriched with unsaturated fatty acids during this period of growth at 24 °C, this enrichment was not accompanied by an increased growth rate of the culture. However, the period of growth at 24 °C did result in bacteria that could grow more rapidly at 10 °C than could bacteria directly transferred from cultures grown at 37 °C. These observations suggest that the increase in membrane fluidity that occurs when bacteria are grown at 24 °C does not allow bacteria to grow faster at 24 °C, but rather allows them to adapt more readily to further decreases in growth temperature.