Browsing by Author "Jiang, Sharon"
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Item Open Access Antibiotic-induced changes in the microbiota disrupt redox dynamics in the gut.(eLife, 2018-06-19) Reese, Aspen T; Cho, Eugenia H; Klitzman, Bruce; Nichols, Scott P; Wisniewski, Natalie A; Villa, Max M; Durand, Heather K; Jiang, Sharon; Midani, Firas S; Nimmagadda, Sai N; O'Connell, Thomas M; Wright, Justin P; Deshusses, Marc A; David, Lawrence AHow host and microbial factors combine to structure gut microbial communities remains incompletely understood. Redox potential is an important environmental feature affected by both host and microbial actions. We assessed how antibiotics, which can impact host and microbial function, change redox state and how this contributes to post-antibiotic succession. We showed gut redox potential increased within hours of an antibiotic dose in mice. Host and microbial functioning changed under treatment, but shifts in redox potentials could be attributed specifically to bacterial suppression in a host-free ex vivo human gut microbiota model. Redox dynamics were linked to blooms of the bacterial family Enterobacteriaceae. Ecological succession to pre-treatment composition was associated with recovery of gut redox, but also required dispersal from unaffected gut communities. As bacterial competition for electron acceptors can be a key ecological factor structuring gut communities, these results support the potential for manipulating gut microbiota through managing bacterial respiration.Item Open Access Ecological memory of prior nutrient exposure in the human gut microbiome.(The ISME journal, 2022-07-23) Letourneau, Jeffrey; Holmes, Zachary C; Dallow, Eric P; Durand, Heather K; Jiang, Sharon; Carrion, Verónica M; Gupta, Savita K; Mincey, Adam C; Muehlbauer, Michael J; Bain, James R; David, Lawrence AMany ecosystems have been shown to retain a memory of past conditions, which in turn affects how they respond to future stimuli. In microbial ecosystems, community disturbance has been associated with lasting impacts on microbiome structure. However, whether microbial communities alter their response to repeated stimulus remains incompletely understood. Using the human gut microbiome as a model, we show that bacterial communities retain an "ecological memory" of past carbohydrate exposures. Memory of the prebiotic inulin was encoded within a day of supplementation among a cohort of human study participants. Using in vitro gut microbial models, we demonstrated that the strength of ecological memory scales with nutrient dose and persists for days. We found evidence that memory is seeded by transcriptional changes among primary degraders of inulin within hours of nutrient exposure, and that subsequent changes in the activity and abundance of these taxa are sufficient to enhance overall community nutrient metabolism. We also observed that ecological memory of one carbohydrate species impacts microbiome response to other carbohydrates, and that an individual's habitual exposure to dietary fiber was associated with their gut microbiome's efficiency at digesting inulin. Together, these findings suggest that the human gut microbiome's metabolic potential reflects dietary exposures over preceding days and changes within hours of exposure to a novel nutrient. The dynamics of this ecological memory also highlight the potential for intra-individual microbiome variation to affect the design and interpretation of interventions involving the gut microbiome.