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Miguel A. Alvarez - One of the best experts on this subject based on the ideXlab platform.
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The tyrosyl-tRNA synthetase like gene located in the tyramine biosynthesis cluster of Enterococcus durans is transcriptionally regulated by tyrosine concentration and extracellular pH
BMC microbiology, 2012Co-Authors: Daniel M. Linares, Victor Ladero, Maria Fernandez, Beatriz Del-río, Maria Cruz Martin, Miguel A. AlvarezAbstract:Background The tyramine producer Enterococcus durans IPLA655 contains all the necessary genes for tyramine biosynthesis, grouped in the TDC cluster. This cluster includes tyrS, an aminoacyl-tRNA synthetase like gene.
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Role of tyramine synthesis by food-borne Enterococcus durans in adaptation to the gastrointestinal tract environment
Applied and Environmental Microbiology, 2011Co-Authors: Pilar Fernández De Palencia, Maria Luz Mohedano, Cristina Quevedo, Victor Ladero, Maria Fernandez, Miguel A. Alvarez, Paloma LopezAbstract:Biogenic amines in food constitute a human health risk. Here we report that tyramine-producing Enterococcus durans strain IPLA655 (from cheese) was able to produce tyramine under conditions simulating transit through the gastrointestinal tract. Activation of the tyramine biosynthetic pathway contributed to binding and immunomodulation of enterocytes.
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Tyramine biosynthesis in Enterococcus durans is transcriptionally regulated by the extracellular pH and tyrosine concentration
Microbial biotechnology, 2009Co-Authors: Daniel M. Linares, Maria Fernandez, M. Cruz Martín, Miguel A. AlvarezAbstract:The microbial decarboxylation of some amino acids leads to the undesirable presence of biogenic amines in foods. One of the most abundant and frequent biogenic amines found in fermented foods is tyramine, which is produced by the decarboxylation of tyrosine. In the present work, transcriptional analysis of tyramine biosynthesis in Enterococcus durans IPLA655, a strain isolated from cheese, was studied. The gene coding for the tyrosine decarboxylase (tdcA) and that coding for the tyrosine‐tyramine antiporter (tyrP) form an operon transcribed from the promoter PtdcA, 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.
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Factors affecting tyramine production in Enterococcus durans IPLA 655
Applied microbiology and biotechnology, 2006Co-Authors: Maria Fernandez, Daniel M. Linares, Ana Rodríguez, Miguel A. AlvarezAbstract:The decarboxylation of tyrosine by certain lactic acid bacteria leads to the undesirable presence of tyramine in fermented foods. Tyramine is the most frequent biogenic amine found in cheese and is also commonly found in other fermented foods and beverages. The tyramine-producing strain Enterococcus durans IPLA 655 was grown in a bioreactor under different conditions to determine the influence of carbon source, tyrosine and tyramine concentrations, and pH on tyramine production. The carbon source appeared to have no significant effect on the production of tyramine. In contrast, tyrosine was necessary for tyramine production, while the presence of tyramine itself in the growth medium inhibited such production. pH showed by far the greatest influence on tyramine synthesis; tyramine was produced in the greatest quantities at pH 5.0, although this was accompanied by a reduced growth rate.
Daniel M. Linares - One of the best experts on this subject based on the ideXlab platform.
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The tyrosyl-tRNA synthetase like gene located in the tyramine biosynthesis cluster of Enterococcus durans is transcriptionally regulated by tyrosine concentration and extracellular pH
BMC microbiology, 2012Co-Authors: Daniel M. Linares, Victor Ladero, Maria Fernandez, Beatriz Del-río, Maria Cruz Martin, Miguel A. AlvarezAbstract:Background The tyramine producer Enterococcus durans IPLA655 contains all the necessary genes for tyramine biosynthesis, grouped in the TDC cluster. This cluster includes tyrS, an aminoacyl-tRNA synthetase like gene.
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Tyramine biosynthesis in Enterococcus durans is transcriptionally regulated by the extracellular pH and tyrosine concentration
Microbial biotechnology, 2009Co-Authors: Daniel M. Linares, Maria Fernandez, M. Cruz Martín, Miguel A. AlvarezAbstract:The microbial decarboxylation of some amino acids leads to the undesirable presence of biogenic amines in foods. One of the most abundant and frequent biogenic amines found in fermented foods is tyramine, which is produced by the decarboxylation of tyrosine. In the present work, transcriptional analysis of tyramine biosynthesis in Enterococcus durans IPLA655, a strain isolated from cheese, was studied. The gene coding for the tyrosine decarboxylase (tdcA) and that coding for the tyrosine‐tyramine antiporter (tyrP) form an operon transcribed from the promoter PtdcA, 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.
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Factors affecting tyramine production in Enterococcus durans IPLA 655
Applied microbiology and biotechnology, 2006Co-Authors: Maria Fernandez, Daniel M. Linares, Ana Rodríguez, Miguel A. AlvarezAbstract:The decarboxylation of tyrosine by certain lactic acid bacteria leads to the undesirable presence of tyramine in fermented foods. Tyramine is the most frequent biogenic amine found in cheese and is also commonly found in other fermented foods and beverages. The tyramine-producing strain Enterococcus durans IPLA 655 was grown in a bioreactor under different conditions to determine the influence of carbon source, tyrosine and tyramine concentrations, and pH on tyramine production. The carbon source appeared to have no significant effect on the production of tyramine. In contrast, tyrosine was necessary for tyramine production, while the presence of tyramine itself in the growth medium inhibited such production. pH showed by far the greatest influence on tyramine synthesis; tyramine was produced in the greatest quantities at pH 5.0, although this was accompanied by a reduced growth rate.
Maria Fernandez - One of the best experts on this subject based on the ideXlab platform.
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The tyrosyl-tRNA synthetase like gene located in the tyramine biosynthesis cluster of Enterococcus durans is transcriptionally regulated by tyrosine concentration and extracellular pH
BMC microbiology, 2012Co-Authors: Daniel M. Linares, Victor Ladero, Maria Fernandez, Beatriz Del-río, Maria Cruz Martin, Miguel A. AlvarezAbstract:Background The tyramine producer Enterococcus durans IPLA655 contains all the necessary genes for tyramine biosynthesis, grouped in the TDC cluster. This cluster includes tyrS, an aminoacyl-tRNA synthetase like gene.
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Role of tyramine synthesis by food-borne Enterococcus durans in adaptation to the gastrointestinal tract environment
Applied and Environmental Microbiology, 2011Co-Authors: Pilar Fernández De Palencia, Maria Luz Mohedano, Cristina Quevedo, Victor Ladero, Maria Fernandez, Miguel A. Alvarez, Paloma LopezAbstract:Biogenic amines in food constitute a human health risk. Here we report that tyramine-producing Enterococcus durans strain IPLA655 (from cheese) was able to produce tyramine under conditions simulating transit through the gastrointestinal tract. Activation of the tyramine biosynthetic pathway contributed to binding and immunomodulation of enterocytes.
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Tyramine biosynthesis in Enterococcus durans is transcriptionally regulated by the extracellular pH and tyrosine concentration
Microbial biotechnology, 2009Co-Authors: Daniel M. Linares, Maria Fernandez, M. Cruz Martín, Miguel A. AlvarezAbstract:The microbial decarboxylation of some amino acids leads to the undesirable presence of biogenic amines in foods. One of the most abundant and frequent biogenic amines found in fermented foods is tyramine, which is produced by the decarboxylation of tyrosine. In the present work, transcriptional analysis of tyramine biosynthesis in Enterococcus durans IPLA655, a strain isolated from cheese, was studied. The gene coding for the tyrosine decarboxylase (tdcA) and that coding for the tyrosine‐tyramine antiporter (tyrP) form an operon transcribed from the promoter PtdcA, 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.
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Factors affecting tyramine production in Enterococcus durans IPLA 655
Applied microbiology and biotechnology, 2006Co-Authors: Maria Fernandez, Daniel M. Linares, Ana Rodríguez, Miguel A. AlvarezAbstract:The decarboxylation of tyrosine by certain lactic acid bacteria leads to the undesirable presence of tyramine in fermented foods. Tyramine is the most frequent biogenic amine found in cheese and is also commonly found in other fermented foods and beverages. The tyramine-producing strain Enterococcus durans IPLA 655 was grown in a bioreactor under different conditions to determine the influence of carbon source, tyrosine and tyramine concentrations, and pH on tyramine production. The carbon source appeared to have no significant effect on the production of tyramine. In contrast, tyrosine was necessary for tyramine production, while the presence of tyramine itself in the growth medium inhibited such production. pH showed by far the greatest influence on tyramine synthesis; tyramine was produced in the greatest quantities at pH 5.0, although this was accompanied by a reduced growth rate.
Adriano Brandelli - One of the best experts on this subject based on the ideXlab platform.
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Comparative proteomic analysis reveals metabolic variability of probiotic Enterococcus durans during aerobic and anaerobic cultivation.
Journal of proteomics, 2020Co-Authors: Carolina Baldisserotto Comerlato, Adriano Brandelli, Xu Zhang, Krystal Walker, Daniel FigeysAbstract:Abstract The variation in the bioavailability of oxygen constitutes the environmental conditions found by bacteria in their passage through the host gastro-intestinal tract. Given the importance of oxygen in the defense mechanism of bacteria, it is important to understand how bacteria respond to this stress at a metabolic level. The probiotic strain Enterococcus durans LAB18S was cultivated under aerobic and anaerobic conditions using prebiotic oligosaccharides as carbon source. The whole cell proteome and secretome were analyzed through label-free quantitative proteomics approach. The results showed that the LAB18S isolate when grown with fructo-oligosacchrides (FOS) showed a higher number of differentially expressed proteins compared to samples with galacto-oligosaccharides (GOS) or glucose. Clinically important enzymes for the treatment of cancer, L-asparaginase and arginine deiminase, were overexpressed when the isolate was cultured in FOS. In addition, the absence of oxygen induced the strain to produce proteins related to cell multiplication, cell wall integrity and resistance, and H2O2 detoxification. This study showed that E. durans LAB18S growing on FOS was stimulated to produce clinically important biomolecules, including proteins that have been investigated as potential antineoplastic agents. Significance: The probiotic strain E. durans LAB18S produce clinically relevant enzymes for the treatment of cancer when cultivated in symbiosis with fructo-oligosacchrides (FOS). In addition, proteins associated with cellular multiplication, cell wall integrity and resistance, and H2O2 detoxification were induced under anaerobic growth. These characteristics could be relevant to support maintenance of intestinal health.
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Proteomic study of Enterococcus durans LAB18S growing on prebiotic oligosaccharides
Food microbiology, 2020Co-Authors: Carolina Baldisserotto Comerlato, Ana Carolina Ritter, Kendi Nishino Miyamoto, Adriano BrandelliAbstract:Abstract This study evaluates the influence of prebiotic carbohydrates, namely fructooligosaccharides (FOS) and galactooligosaccharides (GOS), on the protein expression of Enterococcus durans LAB18S. The strain was cultivated in 10 g L−1 FOS, GOS or glucose (control) and cellular proteins were extracted for mass spectrometry analysis. A total of 771 proteins were identified and 135 E. durans proteins were validated by the Scaffold algorithm. The proteins were functionally categorized according to Gene Ontology terms. Both FOS and GOS were used as carbon source by E. durans LAB18S, upregulating the production of proteins that may be associated with intestinal mucosa adhesion, carbohydrate and nitrogen metabolism, and stress response. Cells grown with GOS showed an increased expression of the cell division protein divIVA, EF-Tu and glyceraldehyde 3-phosphate dehydrogenase that have been associated with epithelial cell adhesion. The use of FOS stimulated the production of proteins related to amino acid metabolism and energy conversion, and ClpX protein, which plays an important role in protein turnover. The results of this study indicate that FOS and GOS can be metabolized by E. durans and stimulate the microorganism to produce proteins related to some desirable characteristics for a probiotic strain.
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Bioaccumulation and distribution of selenium in Enterococcus durans.
Journal of trace elements in medicine and biology : organ of the Society for Minerals and Trace Elements (GMS), 2016Co-Authors: Simone Pieniz, Robson Andreazza, Flávio Anastácio De Oliveira Camargo, Michele Bertoni Mann, Adriano BrandelliAbstract:Abstract Selenium is an essential nutrient for all living organisms. Under appropriate conditions lactic acid bacteria (LAB) are capable for accumulating large amounts of trace elements, such as selenium, and incorporating them into organic compounds. In this study, the capacity of selenium bioaccumulation by Enterococcus durans LAB18s was evaluated. The distribution of organic selenium in selenium-enriched E. durans LAB18s biomass was analyzed, and the highest percentage of organic selenium was found in the fraction of total protein, followed by the fractions of polysaccharides and nucleic acids. When the protein fraction was obtained by different extractions (water, NaCl, ethanol and NaOH) it was demonstrated that alkali-soluble protein showed the higher Selenium content. Analysis of protein fractions by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed that selenium was present in the proteins ranging from 23 to 100 kDa. The cells were analyzed by scanning electron microscopy (SEM); scanning electron microscopy/energy dispersive spectrometry (SEM/EDS) and transmission electron microscopy (TEM). SEM, TEM and SEM/EDS showed the morphology, the selenium particles bioaccumulated into and on the cells and the amounts of selenium present into the cells, respectively. Thus, the isolate E. durans LAB18s can be a promising probiotic to be used as selenium-enriched biomass in feed trials.
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Evaluation of resistance genes and virulence factors in a food isolated Enterococcus durans with potential probiotic effect
Food Control, 2015Co-Authors: Simone Pieniz, Robson Andreazza, Flávio Anastácio De Oliveira Camargo, Tiane Martin De Moura, Ana Paula Vaz Cassenego, Ana Paula Guedes Frazzon, Adriano BrandelliAbstract:Abstract Enterococci belong to the lactic acid bacteria (LAB) group, which are often considered to provide benefit to the host organism when consumed. However, these microorganisms have a potential as infective agents, being necessary to evaluate the presence of virulence factors and resistance to antibiotics to warrant the safe use of new strains as probiotic cultures. This study aimed to detect genes of potential virulence factors related with adhesion, aggregation, biofilm formation and resistance to vancomycin, in addition to evaluate the antibiotic susceptibility and adhesion capacity of Enterococcus durans LA18s, a strain previously isolated from Minas Frescal cheese. The PCR reactions with specific primers to detect genes of adhesion collagen protein (ace), aggregation substances (agg and asa), bopA (putative glycosyltransferase), bopB (beta-phosphoglucomutase), bopC (aldose 1-epimerase), and bopD (sugar-binding transcriptional regulator) were negative for E. durans LAB18s. In addition, the strain did not present the resistance genes vanA, vanC1 and vanC2/3, and exhibited sensibility to antibiotics commonly used in animal feed, such as erythromycin, tetracycline, vancomycin, gentamicin and penicillin. This strain also showed a strong capacity of biofilm formation and exhibited satisfactory auto-aggregative and hydrophobicity features. The results suggest that this strain can be safely used in animal feed.
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Probiotic potential, antimicrobial and antioxidant activities of Enterococcus durans strain LAB18s
Food Control, 2014Co-Authors: Simone Pieniz, Robson Andreazza, Flávio Anastácio De Oliveira Camargo, Thiago Anghinoni, Adriano BrandelliAbstract:The probiotic potential, antimicrobial and antioxidant properties of Enterococcus durans LAB18s, a strain capable of selenium bioaccumulation, was investigated. E. durans LAB18s showed resistance to acid conditions, showing ability to survive in the presence of simulated gastric juice at pH 3. This bacterium also survived in the presence of simulated intestinal juice with or without bile salts, and did not show hemolytic activity. The antimicrobial activity of culture supernatant and intracellular extract of E. durans LAB18s was tested against different pathogenic microorganisms, namely Listeria monocytogenes, Escherichia coli, Bacillus cereus, Staphylococcus aureus, Salmonella Typhimurium, Salmonella Enteritidis, Pseudomonas aeruginosa, Aeromonas hydrophila and Corynebacterium fimi. E. durans LAB18s exhibited a broad inhibitory spectrum, except to B. cereus, S. aureus and S. Enteritidis when the culture supernatant was used, and to S. Typhimurium when the intracellular extract was tested. The antioxidant activity of culture supernatant and intracellular extract of E. durans LAB18s was analyzed by ABTS+ and DPPH methods, and only culture supernatant presented ability to scavenge both radicals. Both culture supernatant and intracellular extract showed high antioxidant activity when analyzed by TBARS method. E. durans LAB18s could be useful as a source of dietary selenium supplementation.
Paloma Lopez - One of the best experts on this subject based on the ideXlab platform.
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Role of tyramine synthesis by food-borne Enterococcus durans in adaptation to the gastrointestinal tract environment
Applied and Environmental Microbiology, 2011Co-Authors: Pilar Fernández De Palencia, Maria Luz Mohedano, Cristina Quevedo, Victor Ladero, Maria Fernandez, Miguel A. Alvarez, Paloma LopezAbstract:Biogenic amines in food constitute a human health risk. Here we report that tyramine-producing Enterococcus durans strain IPLA655 (from cheese) was able to produce tyramine under conditions simulating transit through the gastrointestinal tract. Activation of the tyramine biosynthetic pathway contributed to binding and immunomodulation of enterocytes.