Augmentation of growth media for extreme iron-limitation in Escherichia coli
Augmentation of growth media for extreme iron-limitation in Escherichia coli
复制标题
增强大肠杆菌的生长培养基以实现极端铁限制
DOI：
10.1099/acmi.0.000735.v1
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Southwell J
中科院分区：
文献类型：
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作者：
Southwell J
铁是微生物生长的必需营养素，细菌已经进化出多种途径来溶解和溶解这种生物金属，这种生物金属通常以非常低的浓度存在于宿主组织中。我们最近使用MOPS为基础的培养基，以诱导铁限制在大肠杆菌K-12期间的表征新的铁载体结合抗生素。在本研究中，我们确认源自市售M9盐的生长培养基不适合用于铁限制生长的研究，这可能是由于磷酸钠缓冲液成分被超过100 µM的铁污染。相比之下，用金属结合Chelex®树脂处理的基于MOPS的培养基允许游离铁浓度降低至生长限制水平。尽管有这些措施，少量的E。在这些铁耗尽的培养基中仍然观察到大肠杆菌生长。通过培育E.在理论上增加对铁依赖性酶的需求的条件下，即通过将葡萄糖碳源替换为乙酸盐并切换到微需氧气氛，我们可以进一步减少背景生长。最后，我们证明了通过在E.大肠杆菌，我们可以完全阻止其生长，也许是模仿宿主组织中的情况。总之，这项简短的研究提供了实际的实验洞察低铁培养基和如何增加生长条件的E。极端铁限制生长的大肠杆菌。
Iron is an essential nutrient for microbial growth and bacteria have evolved numerous routes to solubilise and scavenge this biometal, which is often present at very low concentrations in host tissue. We recently used a MOPS-based medium to induce iron limitation in Escherichia coli K-12 during the characterisation of novel siderophore conjugated antibiotics. In this study we confirm that growth media derived from commercially-available M9 salts are unsuitable for studies of iron-limited growth, likely through the contamination of the sodium phosphate buffer components with over 100 µM iron. In contrast, MOPS-based media that are treated with metal-binding Chelex® resin, allow the free iron concentration to be reduced to growth-limiting levels. Despite these measures a small amount of E. coli growth is still observed in these iron-depleted media. By growing E. coli in conditions that theoretically increase the demand for iron-dependent enzymes, namely by replacing the glucose carbon source for acetate and by switching to a microaerobic atmosphere, we can reduce background growth even further. Finally, we demonstrate that by adding an exogeneous siderophore to the growth media which is poorly used by E. coli, we can completely prevent growth, perhaps mimicking situation in host tissue. In conclusion, this short study provides practical experimental insight into low iron media and how to augment the growth conditions of E. coli for extreme iron-limited growth.