Background: The glutamate-dependent decarboxylase (GAD) system is the most potent acid resistance system (AR2) described in Escherichia coli. It consists of a glutamate decarboxylase enzyme and a glutamate/GABA antiporter. Our group showed that the GAD system is also operative in newly described and atypical Brucella species, among which Brucella microti. Recently, an AR2-Q system, based on deamination of glutamine to glutamate by the glutaminase YbaS, was also described in E. coli. In the genome of Brucella, a glsA gene homologous to ybaS is located just upstream and in same orientation as the gadB and gadC genes encoding the GAD system. Objectives: Using a panel of genus-representative strains, our aim was to demonstrate the existence of a functional AR2-Q system in Brucella spp and its contribution to survival at an extreme acid stress. Methods and Results: In contrast to the classical Brucella species studied, only the new and atypical strains were found AR in the presence of glutamine and glutamate. By RT-PCR experiments, the genes of the gadBC-glsA locus were found expressed as an operon. Functional complementation of a glsA mutant of B. microti with the ybaS gene of E. coli demonstrated strong homologies between the 2 enzymes. Acid resistance phenotypes of mutant strains of B. microti confirmed the role of the AR2-Q system in extreme glutamine-dependent AR at pH 2.5. Conclusion: The GAD and AR2-Q systems are functional in new and atypical species of Brucella. This study provides insight into the adaptation of these strains to extremely acidic environments.

The Federation of European Microbiological Societies (FEMS) and the Spanish Society for Microbiology (SEM) have joined​ forces to give you the best of microbiology. Come to the modern and friendly Mediterranean city Valencia, meet fellow microbiologists and update your knowledge with the state of the art on antimicrobial resistance and infections, food microbiology, sustainability, climate change and many more topics. Key disciplines including molecular approaches, biodiversity, bioremediation, eukaryotic microbes, virology and others will be examined in order to advance our understanding of current and future challenges.​​​

Role of the glutamine-dependent acid resistance system of Brucella spp. in response to extreme acid stress / Freddi, Luca; Damiano Maria, Alessandra; Pennacchietti, Eugenia; Köhler, Stephan; DE BIASE, Daniela; Occhialini, Alessandra. - ELETTRONICO. - (2017). (Intervento presentato al convegno FEMS 2017, 7th Congress of European Microbiologists tenutosi a Valencia (Spain) nel 9-13 July 2017).

Role of the glutamine-dependent acid resistance system of Brucella spp. in response to extreme acid stress

Pennacchietti Eugenia;De Biase Daniela;
2017

Abstract

Background: The glutamate-dependent decarboxylase (GAD) system is the most potent acid resistance system (AR2) described in Escherichia coli. It consists of a glutamate decarboxylase enzyme and a glutamate/GABA antiporter. Our group showed that the GAD system is also operative in newly described and atypical Brucella species, among which Brucella microti. Recently, an AR2-Q system, based on deamination of glutamine to glutamate by the glutaminase YbaS, was also described in E. coli. In the genome of Brucella, a glsA gene homologous to ybaS is located just upstream and in same orientation as the gadB and gadC genes encoding the GAD system. Objectives: Using a panel of genus-representative strains, our aim was to demonstrate the existence of a functional AR2-Q system in Brucella spp and its contribution to survival at an extreme acid stress. Methods and Results: In contrast to the classical Brucella species studied, only the new and atypical strains were found AR in the presence of glutamine and glutamate. By RT-PCR experiments, the genes of the gadBC-glsA locus were found expressed as an operon. Functional complementation of a glsA mutant of B. microti with the ybaS gene of E. coli demonstrated strong homologies between the 2 enzymes. Acid resistance phenotypes of mutant strains of B. microti confirmed the role of the AR2-Q system in extreme glutamine-dependent AR at pH 2.5. Conclusion: The GAD and AR2-Q systems are functional in new and atypical species of Brucella. This study provides insight into the adaptation of these strains to extremely acidic environments.
2017
FEMS 2017, 7th Congress of European Microbiologists
The Federation of European Microbiological Societies (FEMS) and the Spanish Society for Microbiology (SEM) have joined​ forces to give you the best of microbiology. Come to the modern and friendly Mediterranean city Valencia, meet fellow microbiologists and update your knowledge with the state of the art on antimicrobial resistance and infections, food microbiology, sustainability, climate change and many more topics. Key disciplines including molecular approaches, biodiversity, bioremediation, eukaryotic microbes, virology and others will be examined in order to advance our understanding of current and future challenges.​​​
04 Pubblicazione in atti di convegno::04d Abstract in atti di convegno
Role of the glutamine-dependent acid resistance system of Brucella spp. in response to extreme acid stress / Freddi, Luca; Damiano Maria, Alessandra; Pennacchietti, Eugenia; Köhler, Stephan; DE BIASE, Daniela; Occhialini, Alessandra. - ELETTRONICO. - (2017). (Intervento presentato al convegno FEMS 2017, 7th Congress of European Microbiologists tenutosi a Valencia (Spain) nel 9-13 July 2017).
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1020435
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