Gut microbiota contribute to host metabolic efficiency by increasing energy availability through the fermentation of dietary fiber and production of short-chain fatty acids (SCFAs) in the colon. SCFAs are proposed to stimulate secretion of the proglucagon (Gcg)-derived incretin hormone GLP-1, which stimulates insulin secretion (incretin response) and inhibits gastric emptying. We find that germ-free (GF) and antibiotic-treated mice, which have severely reduced SCFA levels, have increased basal GLP-1 levels in the plasma and increased Gcg expression in the colon. Increasing energy supply, either through colonization with polysaccharide-fermenting bacteria or through diet, suppressed colonic Gcg expression in GF mice. Increased GLP-1 levels in GF mice did not improve the incretin response but instead slowed intestinal transit. Thus, microbiota regulate the basal levels of GLP-1, and increasing these levels may be an adaptive response to insufficient energy availability in the colon that slows intestinal transit and allows for greater nutrient absorption.
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http://dx.doi.org/10.1016/j.chom.2013.09.012 | DOI Listing |
Front Microbiol
December 2024
Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States.
Microbial activity in the deep continental subsurface is difficult to measure due to low cell densities, low energy fluxes, cryptic elemental cycles and enigmatic metabolisms. Nonetheless, direct access to rare sample sites and sensitive laboratory measurements can be used to better understand the variables that govern microbial life underground. In this study, we sampled fluids from six boreholes at depths ranging from 244 m to 1,478 m below ground at the Sanford Underground Research Facility (SURF), a former goldmine in South Dakota, United States.
View Article and Find Full Text PDFJ Chem Inf Model
January 2025
Department of Chemistry, University of Rome, Sapienza, P.le A. Moro 5, 00185 Rome, Italy.
The oxidation of Met residues in proteins is a complex process, where protein-specific structural and dynamical features play a relevant role in determining the reaction kinetics. Aiming to a full-side perspective, we report here a comprehensive characterization of Met oxidation kinetics by hydrogen peroxide in a leptin protein case study. To do that, we estimated the reaction-free energy profile of the Met oxidation via a QM/MM approach, while the kinetics of the formation of the reactive species were calculated using classical molecular dynamics (MD) simulations.
View Article and Find Full Text PDFSci Rep
January 2025
Raw Building Materials Technology and Processing Research Institute, Housing & Building National Research Center, HBRC, Cairo, Egypt.
Fabrication of heavy density mortar using aggregates reinforced with available solid inorganic chemical additives is of a great importance as a protective layer to mitigate radiations in nuclear facilities. The effect of lead oxide and borax decahydrate on the hydration kinetics was evaluated by determining setting time, leachability and compressive strength. To speed up the reaction, 0.
View Article and Find Full Text PDFEnviron Sci Technol
January 2025
The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
Electrocatalytic nitrate reduction reaction (NORR) to harmless nitrogen (N) presents a viable approach for purifying NO-contaminated wastewater, yet most current electrocatalysts predominantly produce ammonium/ammonia (NH/NH) due to challenges in facilitating N-N coupling. This study focuses on identifying metal catalysts that preferentially generate N and elucidating the mechanistic origins of their high selectivity. Our evaluation of 16 commercially available metals reveals that only Pb, Sn, and In demonstrated substantial N selectivity (79.
View Article and Find Full Text PDFInt J Pharm
January 2025
School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 210009 PR China. Electronic address:
Micronization is frequently employed to increase the dissolution of poorly soluble drugs, but it easily led to powder aggregation and difficult to mix well on the micro level with poor content uniformity and erratic dissolution behavior. Mannitol is the most commonly used pharmaceutical excipient, and its β form (β-mannitol) is commercially available and extensively investigated, whereas form α (α-mannitol) remain poorly understood. Here, this study demonstrated that α-mannitol could significantly eliminate aggregation phenomena of micronized drugs (i.
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