bioRxiv preprint doi: https://doi.org/10.1101/356246; this version posted August 21, 2018. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. Title: Gut bacterial tyrosine decarboxylases restrict the bioavailability of levodopa, the primary treatment in Parkinson’s disease Authors: Sebastiaan P. van Kessel1, Alexandra K. Frye1, Ahmed O. El-Gendy1,2, Maria Castejon1, Ali Keshavarzian3, Gertjan van Dijk4, Sahar El Aidy1*† Affiliations: 1 Department of Molecular Immunology and Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Groningen, The Netherlands. 2 Department of Microbiology and Immunology, Faculty of Pharmacy, Beni-Suef University, Beni-Suef, Egypt 3 Division of Digestive Disease and Nutrition, Section of Gastroenterology, Department of Internal Medicine, Rush University Medical Center, Chicago, Illinois. 4 Department of Behavioral Neuroscience, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, The Netherlands. * Corresponding author. Email:
[email protected] † Present address: Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Nijenborg 7, 9747 AG Groningen, The Netherlands. P:+31(0)503632201. 1 bioRxiv preprint doi: https://doi.org/10.1101/356246; this version posted August 21, 2018. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. Summary Human gut bacteria play a critical role in the regulation of immune and metabolic systems, as well as in the function of the nervous system. The microbiota senses its environment and responds by releasing metabolites, some of which are key regulators of human health and disease.