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Growth, biogenic amine production and tyr DC transcription of Enterococcus faecalis in synthetic medium containing defined amino acid concentrations
Author(s) -
Bargossi E.,
Tabanelli G.,
Montanari C.,
Gatto V.,
Chinnici F.,
Gardini F.,
Torriani S.
Publication year - 2017
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/jam.13406
Subject(s) - enterococcus faecalis , tyramine , tyrosine , biogenic amine , biochemistry , biology , phenylalanine , transcription (linguistics) , gene expression , chemistry , amino acid , food science , gene , escherichia coli , linguistics , philosophy , receptor , neurotransmitter
Aims The tyraminogenic potential of the strains Enterococcus faecalis EF 37 and ATCC 29212 was investigated in a synthetic medium containing defined amounts of tyrosine and phenylalanine at different temperatures. Methods and Results Enterococci growth and the production of biogenic amines (BA) were evaluated in relation to their pre‐growth in medium containing tyrosine. Significant differences between the two strains were evidenced at metabolic level. Both the pre‐adapted strains grew faster in all the tested conditions, independently of the presence of the precursor. Temperatures of 30 and 40°C positively affected the growth parameters. The tyrosine decarboxylase (tyrDC) activity of the strain EF 37 was positively affected by pre‐adaptation, while ATCC 29212 showed a faster and higher tyramine accumulation with not‐adapted cells. The expression analysis of the gene tyr DC confirmed the influence of the growth conditions on gene transcription. Conclusions The small differences found between the two strains in the maximum transcript level reached rapidly after the inoculum and the different behaviour in the tyramine accumulation suggested the possible involvement of complex regulation mechanisms on the tyrDC or on the membrane transport systems, which could affect the different BA accumulation trend. Significance and Impact of the Study This study gives deeper insight into the metabolic regulation of tyrDC activity of enterococci.