Laboratory of Systems and Synthetic Biology, Wageningen University and Research, Wageningen, the Netherlands.
INRA, UMR 1332 de Biologie du Fruit et Pathologie, F-33140, Villenave d'Ornon, France.
NPJ Syst Biol Appl. 2020 Oct 23;6(1):33. doi: 10.1038/s41540-020-00153-7.
Mycoplasma pneumoniae is a slow-growing, human pathogen that causes atypical pneumonia. Because it lacks a cell wall, many antibiotics are ineffective. Due to its reduced genome and dearth of many biosynthetic pathways, this fastidious bacterium depends on rich, undefined medium for growth, which makes large-scale cultivation challenging and expensive. To understand factors limiting growth, we developed a genome-scale, constraint-based model of M. pneumoniae called iEG158_mpn to describe the metabolic potential of this bacterium. We have put special emphasis on cell membrane formation to identify key lipid components to maximize bacterial growth. We have used this knowledge to predict essential components validated with in vitro serum-free media able to sustain growth. Our findings also show that glycolysis and lipid metabolism are much less efficient under hypoxia; these findings suggest that factors other than metabolism and membrane formation alone affect the growth of M. pneumoniae. Altogether, our modelling approach allowed us to optimize medium composition, enabled growth in defined media and streamlined operational requirements, thereby providing the basis for stable, reproducible and less expensive production.
肺炎支原体是一种生长缓慢的人类病原体，可引起非典型肺炎。由于缺乏细胞壁，许多抗生素无效。由于其基因组较小且缺乏许多生物合成途径，这种苛刻的细菌依赖于丰富的、未定义的培养基来生长，这使得大规模培养具有挑战性和昂贵。为了了解限制生长的因素，我们开发了一种肺炎支原体的基于基因组规模的约束模型，称为 iEG158_mpn，以描述该细菌的代谢潜力。我们特别强调细胞膜的形成，以确定关键的脂质成分，以最大限度地提高细菌的生长。我们利用这些知识来预测关键成分，并用能够维持生长的体外无血清培养基进行验证。我们的研究结果还表明，在低氧条件下糖酵解和脂质代谢的效率要低得多；这些发现表明，除了代谢和膜形成之外，其他因素也会影响肺炎支原体的生长。总的来说，我们的建模方法允许我们优化培养基组成，使在定义的培养基中生长成为可能，并简化了操作要求，从而为稳定、可重复和更便宜的生产提供了基础。
