Hofmann Julia D, Otto Andreas, Berges Mareike, Biedendieck Rebekka, Michel Annika-Marisa, Becher Dörte, Jahn Dieter, Neumann-Schaal Meina
Department of Bioinformatics and Biochemistry, Technische Universität Braunschweig, Braunschweig, Germany.
Braunschweig Integrated Centre of Systems Biology (BRICS), Braunschweig, Germany.
Front Microbiol. 2018 Aug 21;9:1970. doi: 10.3389/fmicb.2018.01970. eCollection 2018.
The obligate anaerobe, spore forming bacterium (formerly ) causes nosocomial and community acquired diarrhea often associated with antibiotic therapy. Major virulence factors of the bacterium are the two large clostridial toxins TcdA and TcdB. The production of both toxins was found strongly connected to the metabolism and the nutritional status of the growth environment. Here, we systematically investigated the changes of the gene regulatory, proteomic and metabolic networks of 630Δ underlying the adaptation to the non-growing state in the stationary phase. Integrated data from time-resolved transcriptome, proteome and metabolome investigations performed under defined growth conditions uncovered multiple adaptation strategies. Overall changes in the cellular processes included the downregulation of ribosome production, lipid metabolism, cold shock proteins, spermine biosynthesis, and glycolysis and in the later stages of riboflavin and coenzyme A (CoA) biosynthesis. In contrast, different chaperones, several fermentation pathways, and cysteine, serine, and pantothenate biosynthesis were found upregulated. Focusing on the Stickland amino acid fermentation and the central carbon metabolism, we discovered the ability of to replenish its favored amino acid cysteine by a pathway starting from the glycolytic 3-phosphoglycerate via L-serine as intermediate. Following the growth course, the reductive equivalent pathways used were sequentially shifted from proline via leucine/phenylalanine to the central carbon metabolism first to butanoate fermentation and then further to lactate fermentation. The toxin production was found correlated mainly to fluxes of the central carbon metabolism. Toxin formation in the supernatant was detected when the flux changed from butanoate to lactate synthesis in the late stationary phase. The holistic view derived from the combination of transcriptome, proteome and metabolome data allowed us to uncover the major metabolic strategies that are used by the clostridial cells to maintain its cellular homeostasis and ensure survival under starvation conditions.
专性厌氧菌、产芽孢细菌（以前称为 ）会引发常与抗生素治疗相关的医院获得性和社区获得性腹泻。该细菌的主要毒力因子是两种大型梭菌毒素TcdA和TcdB。发现这两种毒素的产生与生长环境的代谢和营养状况密切相关。在此，我们系统地研究了630Δ在适应稳定期非生长状态时基因调控、蛋白质组和代谢网络的变化。在确定的生长条件下进行的时间分辨转录组、蛋白质组和代谢组研究的综合数据揭示了多种适应策略。细胞过程的总体变化包括核糖体产生、脂质代谢、冷休克蛋白、精胺生物合成、糖酵解以及核黄素和辅酶A（CoA）生物合成后期阶段的下调。相比之下，发现不同的伴侣蛋白、几种发酵途径以及半胱氨酸、丝氨酸和泛酸生物合成上调。聚焦于斯特克兰德氨基酸发酵和中心碳代谢，我们发现该菌能够通过一条从糖酵解的3-磷酸甘油酸经L-丝氨酸作为中间产物开始的途径来补充其偏好的氨基酸半胱氨酸。随着生长过程，所使用的还原当量途径依次从脯氨酸经亮氨酸/苯丙氨酸转移到中心碳代谢，首先是丁酸发酵，然后进一步是乳酸发酵。发现毒素产生主要与中心碳代谢通量相关。当通量在稳定期末期从丁酸合成转变为乳酸合成时，在上清液中检测到毒素形成。转录组、蛋白质组和代谢组数据相结合得出的整体观点使我们能够揭示梭菌细胞用于维持其细胞内稳态并确保在饥饿条件下存活的主要代谢策略。
