Time-resolved selected ion flow tube mass spectrometric quantification of the volatile compounds generated by E. coli JM109 cultured in two different media
Time-resolved selected ion flow tube mass spectrometric quantification of the volatile compounds generated by E. coli JM109 cultured in two different media
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DOI：
10.1002/rcm.5099
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发表时间：
2011-08-15
影响因子：
2
通讯作者：
Smith, David
中科院分区：
文献类型：
--
作者：
Chippendale, Thomas W. E.;Spanel, Patrik;Smith, David
利用选择离子流动管质谱(SIFT-MS)对在常用的Dulbecco‘s Modify Eagle’s Medium(DMEM)和Lysgeny Broth(LB)中培养的细菌JM109所释放的挥发性化合物进行了初步测量，作为对哺乳动物细胞培养物意外感染的实时、非侵入性监测的一步。在一种方法中，将单独的培养液和大肠杆菌细胞/培养液组合保存在用隔膜密封的瓶子中，在37摄氏度下保持给定的时间段，通常是过夜，以允许细菌增殖，然后用SIFT-MS直接分析捕获的顶空。根据所使用的液体培养基，大肠杆菌细胞可以产生几种化合物：当在DMEM中培养时，会产生大量的乙醇、乙醛和硫化氢；在LB中，氨是主要的挥发性产物。在第二个程序中，为了确保细胞培养中普遍存在好氧条件，选择的挥发性化合物通过SIFT-MS在保持在接近37℃的露天大肠杆菌/DMEM培养上实时监测几个小时。一些化合物浓度的时间变化反映了它们在培养物中的产量，表明是最大值。因此，乙醇和乙醛产生的最大值反映了旺盛的大肠杆菌细胞从DMEM中还原葡萄糖的情况，而硫化氢水平的最大值表明DMEM中含硫氨基酸的损失。偶然的是，当观察到大量氨的产生时，观察到DMEM无意中感染了酮杆菌的排放。这项初步研究的结果表明，监测挥发性化合物可能有助于及早发现大型生物反应器中的细菌感染。版权所有(C)2011 John Wiley&Sons，Ltd.
Preliminary measurements have been made of the volatile compounds emitted by the bacterium E. coli JM109 cultured in the commonly used media Dulbecco's modified Eagle's medium (DMEM) and lysogeny broth (LB) using selected ion flow tube mass spectrometry, SIFT-MS, as a step towards the real time, non-invasive monitoring of accidental infections of mammalian cell cultures. In one procedure, the culture medium alone and the E. coli cells/medium combination were held at 37 degrees C in bottles sealed with septa for a given time period, usually overnight, to allow the bacterium to proliferate, after which the captured headspace was analysed directly by SIFT-MS. Several compounds were seen to be produced by the E. coli cells that depended on the liquid medium used: when cultured in DMEM, copious amounts of ethanol, acetaldehyde and hydrogen sulphide were produced; in LB ammonia is the major volatile product. In a second procedure, to ensure aerobic conditions prevailed in the cell culture, selected volatile compounds were monitored by SIFT-MS in real time for several hours above the open-to-air E. coli/DMEM culture held at close to 37 degrees C. The temporal variations in the concentrations of some compounds, which reflect their production rates in the culture, indicate maxima. Thus, the maxima in the ethanol and acetaldehyde production are a reflection of the reduction of glucose from the DMEM by the vigorous E. coli cells and the maximum in the hydrogen sulphide level is an indication of the loss of the sulphur-bearing amino acids from the DMEM. Serendipitously, emissions from DMEM inadvertently infected with the bacterium C. testosteroni were observed when large quantities of ammonia were seen to be produced. The results of this preliminary study suggest that monitoring volatile compounds might assist in the early detection of bacterial infection in large-scale bioreactors. Copyright (C) 2011 John Wiley & Sons, Ltd.