Article Occurrence and Function of the Na+-Translocating NADH:Quinone Oxidoreductase in Prevotella spp. Simon Deusch 1, Eva Bok 2,†, Lena Schleicher 2, Jana Seifert 1,* and Julia Steuber 2,* 1 Institute of Animal Science, University of Hohenheim, 70599 Stuttgart, Germany; deusch@uni- hohenheim.de 2 Institute of Microbiology, University of Hohenheim, 70599 Stuttgart, Germany;
[email protected] tuebingen.de (E.B.);
[email protected] (L.S.) * Correspondence:
[email protected] (J.Se.);
[email protected] (J.St.); Tel.: +49(0)71145923520 (J.Se.); +49(0)71145922228 (J.St.) † Present address: Interfaculty Institute of Microbiology and Infection Medicine, University Tübingen, 72076 Tübingen, Germany. Received: 5 February 2019; Accepted: 25 April 2019; Published: 27 April 2019 Abstract: Strictly anaerobic Prevotella spp. are characterized by their vast metabolic potential. As members of the Prevotellaceae family, they represent the most abundant organisms in the rumen and are typically found in monogastrics such as pigs and humans. Within their largely anoxic habitats, these bacteria are considered to rely primarily on fermentation for energy conservation. A recent study of the rumen microbiome identified multiple subunits of the Na+-translocating NADH:quinone oxidoreductase (NQR) belonging to different Prevotella spp. Commonly, the NQR is associated with biochemical energy generation by respiration. The existence of this Na+ pump in Prevotella spp. may indicate an important role for electrochemical Na+ gradients in their anaerobic metabolism. However, detailed information about the potential activity of the NQR in Prevotella spp. is not available. Here, the presence of a functioning NQR in the strictly anaerobic model organism P.