Nucleoside uptake in Vibrio cholerae and its role in the transition fitness from host to environment

• Published in: Molecular microbiology Vol. 99; no. 3; pp. 470 - 483
• Main Authors: Gumpenberger, Tanja, Vorkapic, Dina, Zingl, Franz G., Pressler, Katharina, Lackner, Stefanie, Seper, Andrea, Reidl, Joachim, Schild, Stefan
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.02.2016
• Subjects: Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Biological Transport; Cholera; Cholera - metabolism; Cholera - microbiology; Gene Expression Regulation, Bacterial; Humans; Life cycles; Microbiology; Mutation; Nucleoside Transport Proteins - genetics; Nucleoside Transport Proteins - metabolism; Nucleosides - metabolism; Vibrio cholerae; Vibrio cholerae - genetics; Vibrio cholerae - metabolism
• ISSN: 0950-382X; 1365-2958
• DOI: 10.1111/mmi.13143

Summary As it became evident recently, extracellular DNA could be a versatile nutrient source of the facultative pathogen Vibrio cholerae along the different stages of its life cycle. By the use of two extracellular nucleases and periplasmic phosphatases, V. cholerae degrades extracellular DNA to nucleosides. In this study, we investigated the nucleoside uptake via identification and characterization of VCA0179, VC1953 and VC2352 representing the three nucleoside transport systems in V. cholerae. Based on our results VC2352 seems to be the dominant nucleoside transporter. Nevertheless, all three transporters are functional and can contribute to the utilization of nucleosides as a sole source of carbon or nitrogen. We found that the transcriptional activity of these three distal genes is equally promoted or antagonized by CRP or CytR respectively. Finally, mutants impaired for nucleoside uptake exhibit decreased transition fitness from the host into low carbon environments along the life cycle of V. cholerae. Extracellular DNA represents an abundant biopolymer of the Vibrio cholerae biofilm matrix and can be degraded to the nucleoside level by extracellular nucleases and phosphatases. We characterized three functional nucleoside transport systems, which contribute to the utilization of nucleosides as a nutrient source, and play a physiological role along the lifecycle of V. cholerae. Impaired nucleoside uptake not only alters biofilm formation, but also reduces survival fitness from the host into low carbon environments.