Illustration of the Conclusion (IMAGE) University of Groningen Caption The presence of more bacteria producing the tyrosine decarboxylase (TDC) enzyme means less levodopa in the bloodstream. Credit S. El Aidy, University of Groningen Usage Restrictions With credit License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.