TI Food and Nutrition, Nieuwe Kanaal, Wageningen, The Netherlands.
Lett Appl Microbiol. 2010 Jan;50(1):57-64. doi: 10.1111/j.1472-765X.2009.02752.x.
A medium with minimal requirements for the growth of Lactobacillus plantarum WCFS was developed. The composition of the minimal medium was compared to a genome-scale metabolic model of L. plantarum.
By repetitive single omission experiments, two minimal media were developed: PMM5 (true minimal medium) and PMM7 [a pseudominimal medium, supporting proper biomass formation of 350 mg l(-1) dry weight (DW)]. The specific growth rate of L. plantarum on PMM7 was found to be 50% and 63% lower when compared to growth on established growth media (chemically defined medium and MRS, respectively). Using a genome-scale metabolic model of L. plantarum, it was predicted that PMM5 and PMM7 would not support the growth of L. plantarum. This is because the biosynthesis of para-aminobenzoic acid (pABA) was predicted to be essential for growth. The discrepancy in simulated growth and experimental growth on PMM7 was further investigated for pABA; a molecule which plays an important role in folate production. The growth performance and folate production were determined on PMM7 in the presence and absence of pABA. It was found that a 12,000-fold reduction in folate pools exerted no influence on formation of biomass or growth rate of L. plantarum cultures when grown in the absence of pABA.
Largely reduced folate production pools do not have an effect on the growth of L. plantarum, showing that L. plantarum makes folate in a large excess.
These experiments illustrate the importance of combining genome-scale metabolic models with growth experiments on minimal media.
开发一种对植物乳杆菌 WCFS 生长要求最低的培养基。将该最小培养基的组成与植物乳杆菌的基因组规模代谢模型进行比较。
通过重复单缺实验，开发了两种最小培养基：PMM5（真正的最小培养基）和 PMM7[一种伪最小培养基，支持 350mg l(-1)干重（DW）的适当生物量形成]。与在已建立的生长培养基（化学定义培养基和 MRS）上生长相比，植物乳杆菌在 PMM7 上的比生长速率分别降低了 50%和 63%。使用植物乳杆菌的基因组规模代谢模型，预测 PMM5 和 PMM7 不会支持植物乳杆菌的生长。这是因为预测对邻氨基苯甲酸（pABA）的生物合成是生长所必需的。进一步研究了 PMM7 上模拟生长和实验生长之间的差异对于 pABA 的影响；pABA 在叶酸产生中起着重要作用。在 PMM7 中存在和不存在 pABA 的情况下，测定了生长性能和叶酸产量。结果发现，当在不存在 pABA 的情况下生长时，叶酸库的 12000 倍减少对植物乳杆菌培养物生物量形成或生长速率没有影响。
叶酸产量的大幅减少对植物乳杆菌的生长没有影响，表明植物乳杆菌过量产生叶酸。
这些实验说明了将基因组规模代谢模型与最小培养基上的生长实验相结合的重要性。
