Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
Microbiologyopen. 2013 Oct;2(5):841-52. doi: 10.1002/mbo3.121. Epub 2013 Aug 28.
We studied the impact of a sublethal concentration of erythromycin on the fitness and proteome of a continuously cultivated population of Escherichia coli. The development of resistance to erythromycin in the population was followed over time by the gradient plate method and minimum inhibitory concentration (MIC) measurements. We measured the growth rate, standardized efficiency of synthesis of radiolabeled proteins, and translation accuracy of the system. The proteome changes were followed over time in two parallel experiments that differed in the presence or absence of erythromycin. A comparison of the proteomes at each time point (43, 68, and 103 h) revealed a group of unique proteins differing in expression. From all 35 proteins differing throughout the cultivation, only three were common to more than one time point. In the final population, a significant proportion of upregulated proteins was localized to the outer or inner cytoplasmic membranes or to the periplasmic space. In a population growing for more than 100 generations in the presence of antibiotic, erythromycin-resistant bacterial clones with improved fitness in comparison to early resistant culture predominated. This phenomenon was accompanied by distinct changes in protein expression during a stepwise, population-based development of erythromycin resistance.
我们研究了亚致死浓度红霉素对连续培养的大肠杆菌种群的适应性和蛋白质组的影响。通过梯度平板法和最小抑菌浓度（MIC）测量，我们随时间跟踪了种群中对红霉素的抗性发展。我们测量了系统的生长速率、放射性标记蛋白合成的标准化效率和翻译准确性。在两个平行实验中随时间跟踪蛋白质组变化，其中一个实验存在红霉素，另一个实验不存在。对每个时间点（43、68 和 103 h）的蛋白质组进行比较，发现了一组表达不同的独特蛋白质。在整个培养过程中，从所有 35 种不同的蛋白质中，只有三种在多个时间点都存在。在最终的种群中，上调表达的蛋白质中有很大一部分定位于外细胞质膜、内细胞质膜或周质空间。在抗生素存在的情况下，经过超过 100 代的生长，与早期抗性培养物相比，具有更高适应性的红霉素抗性细菌克隆占主导地位。这种现象伴随着红霉素抗性的逐步、基于群体的发展过程中蛋白质表达的明显变化。
