The Relationship among Tyrosine Decarboxylase and Agmatine Deiminase Pathways in Enterococcus faecalis

Abstract

Enterococci are considered mainly responsible for the undesirable accumulation of the biogenic amines tyramine and putrescine in cheeses. The biosynthesis of tyramine and putrescine has been described as a species trait in Enterococcus faecalis. Tyramine is formed by the decarboxylation of the amino acid tyrosine, by the tyrosine decarboxylase (TDC) route encoded in the tdc cluster. Putrescine is formed from agmatine by the agmatine deiminase (AGDI) pathway encoded in the agdi cluster. These biosynthesis routes have been independently studied, tyrosine and agmatine transcriptionally regulate the tdc and agdi clusters. The objective of the present work is to study the possible co-regulation among TDC and AGDI pathways in E. faecalis. In the presence of agmatine, a positive correlation between putrescine biosynthesis and the tyrosine concentration was found. Transcriptome studies showed that tyrosine induces the transcription of putrescine biosynthesis genes and up-regulates pathways involved in cell growth. The tyrosine modulation over AGDI route was not observed in the mutant Δtdc strain. Fluorescence analyses using gfp as reporter protein revealed PaguB (the promoter of agdi catabolic genes) was induced by tyrosine in the wild-type but not in the mutant strain, confirming that tdc cluster was involved in the tyrosine induction of putrescine biosynthesis. This study also suggests that AguR (the transcriptional regulator of agdi) was implicated in interaction among the two clusters.

Biogenic Amine Production by Lactic Acid Bacteria: A Review

“…Bargossi et al [15,155] have also demonstrated the same effect in other E. faecalis strains. Moreover, Perez et al [154] showed that tyrosine induced putrescine biosynthesis genes, as confirmed by reverse transcription quantitative PCR (RT-qPCR) results. On the other hand, this effect was not observed in the mutant strain, which was unable to decarboxylate tyrosine and produce tyramine, showing that tdc cluster was involved in the tyrosine induction of putrescine biosynthesis.…”

“…In E. faecalis , putrescine is formed from agmatine by the AgDI pathway, which is repressed by carbon source, suggesting a role in the energy production [153]. Perez et al [154] studied the possible co-regulation among TDC and AgDI pathways in E. faecalis . They investigated firstly the tyrosine effect on the tdc cluster transcription of E. faecalis by microarray experiment, highlighting, in the presence of tyrosine, an over-expression of tdcA , tdcP , and nhac-2 genes and a repression of tyrS .…”

Screening Method to Evaluate Amino Acid-Decarboxylase Activity of Bacteria Present in Spanish Artisanal Ripened Cheeses

“…Several authors have described E. faecalis, E. faecium and E. durans as the most frequently TY formers in food [ 12 , 17 , 21 , 23 , 25 , 49 , 50 , 51 , 52 ] and also some strains of E. faecalis and E. faecium have been registered as capable of producing amounts up to 100 mg/L of PU [ 12 , 17 , 21 , 53 ] and CA [ 17 , 21 , 50 ] and/or HI [ 17 , 21 , 54 ]. Tyrosine is a relevant amino acid for the formation of BA in cheese as it can be an inducer of PU production in E. faecalis and would be received by the enterococci cells as a signal to growth, what would lead in an increment in the number of BA-producing cells increasing the risk of accumulating TY and PU in cheese [ 55 ]. No references concerning histidine decarboxylase activity of E. durans have been found in the literature.…”

“…Several studies have reported different species of LAB able to form BA, especially TY [ 8 , 11 , 16 , 17 , 18 , 21 , 23 , 25 , 50 , 54 , 55 , 56 , 57 ], but also HI [ 58 , 59 ]. Within the species of LAB that may occur in food some strains of L. brevis and L. plantarum were reported to possess the potential to form TY, PU and/or HI [ 15 , 18 , 21 , 23 , 25 , 60 , 61 ].…”

Construction and characterization of a double mutant of Enterococcus faecalis that does not produce biogenic amines

“…The microarray design was added to the Gene Expression Omnibus (GEO) database (Platform GPL21449). Total RNA was extracted from late exponential phase cultures of the wt and Δ agdi Δ tdc mutant grown in 30 ml of GM17 supplemented with 20 mM of agmatine and 10 mM of tyrosine as previously described 36,37 . 20 µg of RNA were used to synthesize cDNA employing the SuperScript III Reverse Transcriptase Kit (Life Technologies, The Netherlands).…”