|ZHANG, LIQING - Virginia Tech|
|ARGOTY, GUSTAVO ARANGO - Virginia Tech|
|WANG, MINQIAN - Rutgers University|
|KOBORI, MASUKO - National Food Research Institute - Japan|
|PONTIOUS, SHERRI - Temple University|
|XIAO, WEIDONG - Temple University|
Submitted to: Anaerobe
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/10/2016
Publication Date: 12/22/2016
Citation: Firrman, J., Liu, L.S., Zhang, L., Argoty, G., Wang, M., Tomasula, P.M., Kobori, M., Pontious, S., Xiao, W. 2016. The effect of quercetin on genetic expression of the commensal gut microbes bifidobacterium catenulatum, enterococcus caccae and ruminococcus gauvreauii. Anaerobe. 42:130-141. doi: 10.1016/j.anaerobe.2016.10.004. PMID:27742572.
Interpretive Summary: Quercetin is a compound abundantly found in fruits and vegetables and is known to be beneficial to human health. When quercetin is ingested, it is able to pass through the digestive tract to the colon, where it interacts with the resident bacteria. In order to understand the effect that quercetin may have on the bacteria in the colon, the change in growth pattern, cell morphology and gene expression of three different gut bacterial species was determined. The results of these experiments demonstrated that the addition of quercetin affected growth of the three bacterial strains to varying degrees, yet did not change shape or size of the cells. Genetic expression analysis revealed that the addition of quercetin resulted in up-regulation and down-regulation of multiple genes in each strain. For the first time, the effect of quercetin on the growth and genetic expression of three different commensal gut bacteria was documented. The data provides insight into the interactions between compounds in the diet and gut bacterial genetic regulation and growth.
Technical Abstract: Quercetin is one of the most abundant polyphenols found in fruits and vegetables. The ability of the gut microbiota to metabolize quercetin has been previously documented; however, the effect that quercetin may have on commensal gut microbes remains unclear. In the present study, the effects of quercetin on the commensal gut microbes Ruminococcus gauvreauii, Bifidobacterium catenulatum and Enterococcus caccae were determined through evaluation of growth patterns and cell morphology, and analysis of genetic expression profiles between quercetin treated and non-treated groups using Single Molecule RNA sequencing via Helicos technology. Results of this study revealed that phenotypically, quercetin did not prevent growth of Ruminococcus gauvreauii, mildly suppressed growth of Bifidobacterium catenulatum, and moderately inhibited growth of Enterococcus caccae. Genetic analysis revealed that in response to quercetin, Ruminococcus gauvreauii down regulated genes responsible for protein folding, purine synthesis and metabolism. Bifidobacterium catenulatum increased expression of the ABC transport pathway and decreased metabolic pathways and cell wall synthesis. Enterococcus caccae upregulated genes responsible for energy production and metabolism, and downregulated pathways of stress response, translation and sugar transport. For the first time, the effect of quercetin on the growth and genetic expression of three different commensal gut bacteria was documented. The data provides insight into the interactions between genetic regulation and growth. This is also a unique demonstration of how RNA single molecule sequencing can be used to study the gut microbiota.