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Tyramine biosynthesis in Enterococcus durans is transcriptionally regulated by the extracellular pH and tyrosine concentration.

Linares DM, Fernández M, Martín MC, Alvarez MA - Microb Biotechnol (2009)

Bottom Line: One of the most abundant and frequent biogenic amines found in fermented foods is tyramine, which is produced by the decarboxylation of tyrosine.The gene coding for the tyrosine decarboxylase (tdcA) and that coding for the tyrosine-tyramine antiporter (tyrP) form an operon transcribed from the promoter P(tdcA), the expression of which is regulated by the extracellular pH and tyrosine concentration.Quantification of gene expression during the log phase of growth showed high concentrations of tyrosine and acidic pH conditions to induce tdcA-tyrP polycistronic messenger transcription.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Productos Lácteos de Asturias (IPLA), Consejo Superior de Investigaciones Científicas (CSIC), Carretera de Infiesto s/n, 33300 Villaviciosa, Asturias, Spain.

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Reverse transcription‐PCR amplification of the intergenic regions tyrS‐tdcA and tdcA‐tyrP at acidic (+) and non‐acidic pH (−), with (+) and without (−) 10 mM tyrosine; C+, positive control; MW, molecular weight marker.
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f2: Reverse transcription‐PCR amplification of the intergenic regions tyrS‐tdcA and tdcA‐tyrP at acidic (+) and non‐acidic pH (−), with (+) and without (−) 10 mM tyrosine; C+, positive control; MW, molecular weight marker.

Mentions: To confirm that tdcA and tyrP form an operon, reverse transcription‐PCR (RT‐PCR) was performed using primer pairs (Table 2) spanning the junction between each of the open reading frames in this region. Parallel reactions without reverse transcriptase (to control for residual genomic contamination in RNA preparations) failed to yield an amplification product. DNA template controls to ensure PCR fidelity for each primer pair uniformly yielded the expected‐size PCR product (Fig. 2). A band of the expected size was obtained under tyramine production conditions (pH 4.9 and 10 mM tyrosine). This confirms the prediction that tdcA and tyrP constitute an operon. Reverse transcription‐PCR involving the tyrS (the gene upstream tdcA) and tdcA intergenic region yielded no PCR product (Fig. 2), suggesting that transcription is initiated from the tdcA promoter.


Tyramine biosynthesis in Enterococcus durans is transcriptionally regulated by the extracellular pH and tyrosine concentration.

Linares DM, Fernández M, Martín MC, Alvarez MA - Microb Biotechnol (2009)

Reverse transcription‐PCR amplification of the intergenic regions tyrS‐tdcA and tdcA‐tyrP at acidic (+) and non‐acidic pH (−), with (+) and without (−) 10 mM tyrosine; C+, positive control; MW, molecular weight marker.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3815318&req=5

f2: Reverse transcription‐PCR amplification of the intergenic regions tyrS‐tdcA and tdcA‐tyrP at acidic (+) and non‐acidic pH (−), with (+) and without (−) 10 mM tyrosine; C+, positive control; MW, molecular weight marker.
Mentions: To confirm that tdcA and tyrP form an operon, reverse transcription‐PCR (RT‐PCR) was performed using primer pairs (Table 2) spanning the junction between each of the open reading frames in this region. Parallel reactions without reverse transcriptase (to control for residual genomic contamination in RNA preparations) failed to yield an amplification product. DNA template controls to ensure PCR fidelity for each primer pair uniformly yielded the expected‐size PCR product (Fig. 2). A band of the expected size was obtained under tyramine production conditions (pH 4.9 and 10 mM tyrosine). This confirms the prediction that tdcA and tyrP constitute an operon. Reverse transcription‐PCR involving the tyrS (the gene upstream tdcA) and tdcA intergenic region yielded no PCR product (Fig. 2), suggesting that transcription is initiated from the tdcA promoter.

Bottom Line: One of the most abundant and frequent biogenic amines found in fermented foods is tyramine, which is produced by the decarboxylation of tyrosine.The gene coding for the tyrosine decarboxylase (tdcA) and that coding for the tyrosine-tyramine antiporter (tyrP) form an operon transcribed from the promoter P(tdcA), the expression of which is regulated by the extracellular pH and tyrosine concentration.Quantification of gene expression during the log phase of growth showed high concentrations of tyrosine and acidic pH conditions to induce tdcA-tyrP polycistronic messenger transcription.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Productos Lácteos de Asturias (IPLA), Consejo Superior de Investigaciones Científicas (CSIC), Carretera de Infiesto s/n, 33300 Villaviciosa, Asturias, Spain.

Show MeSH
Related in: MedlinePlus