caa a22 4500 605504091 CHVBK 20210128100614.0 cr unu---uuuuu 210128e20150401xx s 000 0 eng 10.1007/s00253-014-6301-7 doi (NATIONALLICENCE)springer-10.1007/s00253-014-6301-7 Tyramine biosynthesis is transcriptionally induced at low pH and improves the fitness of Enterococcus faecalis in acidic environments [Elektronische Daten] [Marta Perez, Marina Calles-Enríquez, Ingolf Nes, Maria Martin, Maria Fernandez, Victor Ladero, Miguel Alvarez] Enterococcus faecalis is a commensal bacterium of the human gut that requires the ability to pass through the stomach and therefore cope with low pH. E. faecalis has also been identified as one of the major tyramine producers in fermented food products, where they also encounter acidic environments. In the present work, we have constructed a non-tyramine-producing mutant to study the role of the tyramine biosynthetic pathway, which converts tyrosine to tyramine via amino acid decarboxylation. Wild-type strain showed higher survival in a system that mimics gastrointestinal stress, indicating that the tyramine biosynthetic pathway has a role in acid resistance. Transcriptional analyses of the E. faecalis V583 tyrosine decarboxylase cluster showed that an acidic pH, together with substrate availability, induces its expression and therefore the production of tyramine. The protective role of the tyramine pathway under acidic conditions appears to be exerted through the maintenance of the cytosolic pH. Tyramine production should be considered important in the adaptability of E. faecalis to acidic environments, such as fermented dairy foods, and to survive passage through the human gastrointestinal tract. Springer-Verlag Berlin Heidelberg, 2014 Enterococcus faecalis nationallicence Tyramine nationallicence tdc cluster expression nationallicence Gastrointestinal stress nationallicence Internal pH nationallicence Perez Marta Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Rio Linares s/n, 33300, Villaviciosa, Spain aut Calles-Enríquez Marina Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Rio Linares s/n, 33300, Villaviciosa, Spain aut Nes Ingolf Norwegian University of Life Sciences UMB, Ås, Norway aut Martin Maria Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Rio Linares s/n, 33300, Villaviciosa, Spain aut Fernandez Maria Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Rio Linares s/n, 33300, Villaviciosa, Spain aut Ladero Victor Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Rio Linares s/n, 33300, Villaviciosa, Spain aut Alvarez Miguel Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Rio Linares s/n, 33300, Villaviciosa, Spain aut Applied Microbiology and Biotechnology Springer Berlin Heidelberg 99/8(2015-04-01), 3547-3558 0175-7598 99:8<3547 2015 99 253 https://doi.org/10.1007/s00253-014-6301-7 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00253-014-6301-7 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Perez Marta Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Rio Linares s/n, 33300, Villaviciosa, Spain aut NATIONALLICENCE 700 1- Calles-Enríquez Marina Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Rio Linares s/n, 33300, Villaviciosa, Spain aut NATIONALLICENCE 700 1- Nes Ingolf Norwegian University of Life Sciences UMB, Ås, Norway aut NATIONALLICENCE 700 1- Martin Maria Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Rio Linares s/n, 33300, Villaviciosa, Spain aut NATIONALLICENCE 700 1- Fernandez Maria Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Rio Linares s/n, 33300, Villaviciosa, Spain aut NATIONALLICENCE 700 1- Ladero Victor Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Rio Linares s/n, 33300, Villaviciosa, Spain aut NATIONALLICENCE 700 1- Alvarez Miguel Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Rio Linares s/n, 33300, Villaviciosa, Spain aut NATIONALLICENCE 773 0- Applied Microbiology and Biotechnology Springer Berlin Heidelberg 99/8(2015-04-01), 3547-3558 0175-7598 99:8<3547 2015 99 253