Boyle S M, MacIntyre M F, Sells B H
Biochim Biophys Acta. 1977 Aug 2;477(3):221-7. doi: 10.1016/0005-2787(77)90047-8.
At different exponential growth rates obtained either by varying the carbon source of the culture medium or limiting glucose uptake, intracellular levels of putrescine and spermidine were measured. Over a ten-fold increase in growth rate an approximately three-fold increase in putrescine level and a 3.5-fold increase in spermidine level per cell absorbance were observed. Conditions favoring an abrupt alteration in growth rate, such as occur following nutritional shiftup of Escherichia coli, resulted in a significant increase in the intracellular level of putrescine and virtually no change in the spermidine level. Because of the magnitude and the timing of the change in polyamine levels, the hypothesis that polyamines are (the components) responsible for inducing the rapid increase in the rate of RNA synthesis following nutritional shiftup is rejected.
通过改变培养基的碳源或限制葡萄糖摄取获得不同的指数生长速率，测定了腐胺和亚精胺的细胞内水平。在生长速率增加10倍的情况下，观察到每细胞吸光度的腐胺水平增加约3倍，亚精胺水平增加3.5倍。有利于生长速率突然改变的条件，如大肠杆菌营养上调后出现的情况，导致腐胺的细胞内水平显著增加，而亚精胺水平几乎没有变化。由于多胺水平变化的幅度和时间，多胺是营养上调后诱导RNA合成速率快速增加的（成分）这一假设被否定。
