cyclic-di-GMP modulates a metabolic flux for carbon utilization in Salmonella enterica serovar Typhimurium
- 주제(키워드) Salmonella Typhimurium , c-di-GMP , PTS , Cra
- 주제(DDC) 547
- 발행기관 아주대학교
- 지도교수 윤현진
- 발행년도 2022
- 학위수여년월 2022. 2
- 학위명 석사
- 학과 및 전공 일반대학원 분자과학기술학과
- 실제URI http://www.dcollection.net/handler/ajou/000000031763
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
Salmonella enterica serovar Typhimurium is a primary enteric pathogen that can infect both humans and other animals via animal feces or by consumption of contaminated foods and water. Transmission between humans, animals, and environmental reservoirs, including plants, soil, and water, forced this pathogen to rapidly respond to changing environments and adapt to the new environmental conditions. Cyclic di-GMP (c-di-GMP) is a bacterial second messenger controlling the transitions between planktonic and sessile lifestyles and its concentration is elaborately modulated by multiple metabolizing enzymes in response to environmental cues. This study revealed that c-di-GMP could also alter carbon metabolic pathways in S. Typhimurium. Salmonella producing c-di-GMP at a high concentration decreased the transcription of genes encoding components of three distinct phosphoenolpyruvate (PEP): carbohydrate phosphotransferase systems (PTSs) allocated for the uptake of glucose, mannose, and fructose. The downregulation of PTS genes by c-di-GMP was alleviated in the absence of any of three regulators including SgrS, Mlc, and Cra, suggesting their intermediary roles between c-di-GMP and PTS regulation. On the other hand, the surplus of c-di-GMP increased the transcription of genes important for bacterial gluconeogenesis and this positive role of c-di-GMP in gluconeogenesis disappeared in the absence of Cra, indicating that Cra is a pivotal regulator coordinating a carbon flux between PTS-mediated sugar uptake and gluconeogenesis in response to cellular c-di-GMP concentrations. Considering that gluconeogenesis supplies the precursor sugars required for extracellular polysaccharide production, Salmonella may exploit c-di-GMP as a dual-purpose signal which rewires a carbon flux from glycolysis to gluconeogenesis and promotes biofilm formation using the end products of gluconeogenesis. This study shed light on a new role of c-di-GMP in modulating a carbon flux to coordinate bacterial behavior in response to hostile environments.
more목차
1. Introduction 1
2. Materials and Methods 4
2.1 Bacterial strains and culture condition 4
2.2 Construction of plasmids 7
2.3 Construction of Bacterial strains 7
2.4 RNA extraction 9
2.5 Quantitative real-time PCR analysis 9
3. Results 13
3.1 c-di-GMP downregulated the transcription of genes of PTSGlc, PTSMan, and PTSFru 13
3.2 c-di-GMP did not influence the expression of regulators associated with PTS regulation 18
3.3 c-di-GMP failed to downregulate the transcription of PTS genes in the absence of SgrS 20
3.4 c-di-GMP failed to downregulate the transcription of PTS genes in the absence of Mlc 24
3.5 c-di-GMP failed to downregulate the transcription of PTS genes in the absence of Cra 26
4. Discussion 30
5. Reference 34
