The Experts below are selected from a list of 7392 Experts worldwide ranked by ideXlab platform
Eric Déziel - One of the best experts on this subject based on the ideXlab platform.
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ScmR, a Global Regulator of Gene Expression, Quorum Sensing, pH Homeostasis, and Virulence in Burkholderia thailandensis.
Journal of bacteriology, 2020Co-Authors: Servane Le Guillouzer, Marie-christine Groleau, Florian Mauffrey, Eric DézielAbstract:ABSTRACT The nonpathogenic soil saprophyte Burkholderia thailandensis is a member of the Burkholderia pseudomallei/B. thailandensis/B. mallei group, which also comprises the closely related human pathogens B. pseudomallei and Burkholderia mallei responsible for the melioidosis and glanders diseases, respectively. ScmR, a recently identified LysR-type transcriptional regulator in B. thailandensis, acts as a global transcriptional regulator throughout the stationary phase and modulates the production of a wide range of secondary metabolites, including N-acyl-l-homoserine lactones and 4-hydroxy-3-methyl-2-alkylquinolines and virulence in the Caenorhabditis elegans nematode worm host Model, as well as several quorum sensing (QS)-dependent phenotypes. We have investigated the role of ScmR in B. thailandensis strain E264 during the exponential phase. We used RNA sequencing transcriptomic analyses to identify the ScmR regulon, which was compared to the QS-controlled regulon, showing a considerable overlap between the ScmR-regulated genes and those controlled by QS. We characterized several genes modulated by ScmR using quantitative reverse transcription-PCR or mini-CTX-lux transcriptional reporters, including the oxalate biosynthetic gene obc1 required for pH homeostasis, the orphan LuxR-type transcriptional regulator BtaR5-encoding gene, and the bsa (Burkholderia secretion apparatus) type III secretion system genes essential for both B. pseudomallei and B. mallei pathogenicity, as well as the scmR gene itself. We confirmed that the transcription of scmR is under QS control, presumably ensuring fine-tuned modulation of gene expression. Finally, we demonstrated that ScmR influences virulence using the Fruit Fly Model host Drosophila melanogaster. We conclude that ScmR represents a central component of theB. thailandensis QS regulatory network. IMPORTANCE Coordination of the expression of genes associated with bacterial virulence and environmental adaptation is often dependent on quorum sensing (QS). The QS circuitry of the nonpathogenic bacterium Burkholderia thailandensis, widely used as a Model system for the study of the human pathogen Burkholderia pseudomallei, is complex. We found that the LysR-type transcriptional regulator, ScmR, which is highly conserved and involved in the control of virulence/survival factors in the Burkholderia genus, is a global regulator mediating gene expression through the multiple QS systems coexisting in B. thailandensis, as well as QS independently. We conclude that ScmR represents a key QS modulatory network element, ensuring tight regulation of the transcription of QS-controlled genes, particularly those required for acclimatization to the environment.
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ScmR, a global regulator of gene expression, quorum sensing, pH homeostasis, and virulence in Burkholderia thailandensis
2019Co-Authors: Servane Le Guillouzer, Marie-christine Groleau, Florian Mauffrey, Eric DézielAbstract:Abstract The nonpathogenic soil saprophyte Burkholderia thailandensis is a member of the Burkholderia pseudomallei-thailandensis-mallei (Bptm) group, which also comprises the closely related human pathogens Burkholderia pseudomallei and Burkholderia mallei responsible for the diseases melioidosis and glanders, respectively. ScmR, a recently identified LysR-type transcriptional regulator (LTTR) in B. thailandensis acts as a global transcriptional regulator throughout the stationary phase, and modulates the production of a wide range of secondary metabolites, including N-acyl-L-homoserine lactones (AHLs) and 4-hydroxy-3-methyl-2-alkylquinoline (HMAQ), virulence in the Model host Caenorhabditis elegans, as well as several quorum sensing (QS)-dependent phenotypes. We have investigated the role of ScmR in B. thailandensis strain E264 during the exponential phase. We used RNA-Sequencing (RNA-Seq) transcriptomic analyses to identify the ScmR regulon, which was compared to the QS-controlled regulon, showing a considerable overlap between the ScmR-regulated genes and those controlled by QS. We characterized several genes modulated by ScmR, using quantitative reverse transcription-PCR (qRT-PCR) or mini-CTX-lux transcriptional reporters, including the oxalate biosynthetic gene obc1 required for pH homeostasis, the orphan LuxR-type transcriptional regulator BtaR5-encoding gene, the bsa (Burkholderia secretion apparatus) type III secretion system (T3SS) genes essential for both B. pseudomallei and B. mallei pathogenicity, as well as the scmR gene itself. We confirmed that the transcription of scmR is under QS control, presumably ensuring fine-tuned modulation of gene expression. Finally, we demonstrate that ScmR influences virulence using the Fruit Fly Model host Drosophila melanogaster. We conclude that ScmR represents a central component of the B. thailandensis QS regulatory network. Importance Coordination of the expression of genes associated with bacterial virulence and environmental adaptation is often dependent on quorum sensing (QS). The QS circuitry of the nonpathogenic bacterium Burkholderia thailandensis, which is widely used as a Model system for the study of the human pathogen Burkholderia pseudomallei, is complex. We found that the recently identified LysR-type transcriptional regulator (LTTR), ScmR, which is highly conserved and involved in the control of virulence/survival factors in the Burkholderia genus, is a global regulator mediating gene expression through the multiple QS systems coexisting in B. thailandensis, as well as independently of QS. We conclude that ScmR represents a key QS modulatory network element, ensuring tight regulation of the transcription of QS-controlled genes, particularly those required for acclimatization to the environment.
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Drosophila melanogaster as a Model Host for the Burkholderia cepacia Complex
PloS one, 2010Co-Authors: Josée Castonguay-vanier, Ludovic Vial, Julien Tremblay, Eric DézielAbstract:Background: Colonization with bacterial species from the Burkholderia cepacia complex (Bcc) is associated with fast health decline among individuals with cystic fibrosis. In order to investigate the virulence of the Bcc, several alternative infection Models have been developed. To this end, the Fruit Fly is increasingly used as surrogate host, and its validity to enhance our understanding of host-pathogen relationships has been demonstrated with a variety of microorganisms. Moreover, its relevance as a suitable alternative to mammalian hosts has been confirmed with vertebrate organisms. Methodology/Principal Findings: The aim of this study was to establish Drosophila melanogaster as a surrogate host for species from the Bcc. While the feeding method proved unsuccessful at killing the flies, the pricking technique did generate mortality within the populations. Results obtained with the Fruit Fly Model are comparable with results obtained using mammalian infection Models. Furthermore, validity of the Drosophila infection Model was confirmed with B. cenocepacia K56-2 mutants known to be less virulent in murine hosts or in other alternative Models. Competitive index (CI) analyses were also performed using the Fruit Fly as host. Results of CI experiments agree with those obtained with mammalian Models. Conclusions/Significance: We conclude that Drosophila is a useful alternative infection Model for Bcc and that Fly pricking assays and competition indices are two complementary methods for virulence testing. Moreover, CI results indicate that this method is more sensitive than mortality tests.
Robin L. Cooper - One of the best experts on this subject based on the ideXlab platform.
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A novel educational module to teach neural circuits for college and high school students: NGSS-neurons, genetics, and selective stimulations
F1000Research, 2017Co-Authors: Zana R. Majeed, Felicitas Koch, Joshua Paul Morgan, Heidi Anderson, Jennifer Wilson, Robin L. CooperAbstract:This report introduces various approaches to target defined neural pathways for stimulation and to address the effect of particular neural circuits on behavior in a Model animal, the Fruit Fly ( Drosophila melanogaster ). The objective of this novel educational module described can be used to explain and address principle concepts in neurobiology for high school and college level students. A goal of neurobiology is to show how neural circuit activity controls corresponding behavior in animals. The Fruit Fly Model system provides powerful genetic tools, such as the UAS-Gal4 system, to manipulate expression of non-native proteins in various populations of defined neurons: glutamergic, serotonergic, GABAergic, and cholinergic. The exhibited behaviors in the examples we provide allows teachers and students to address questions from behaviors to details at a cellular level. We provided example sets of data, obtained in a research lab, as well as ideas on ways to present data for participants and instructors. The optogenetic tool, channelrhodpsin 2 (ChR2), is employed to increase the activity of each population of neurons in a spatiotemporal controlled manner in behaving larvae and adult flies. Various behavioral assays are used to observe the effect of a specific neuron population activation on crawling behavior in larvae and climbing behavior in adult flies. Participants using this module become acquainted with the actions of different neurotransmitters in the nervous system. A pre- and post- assessment survey on the content is provided for teachers, as templates, to address learning of content and concepts.
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characterization of development behavior and neuromuscular physiology in the phorid Fly megaselia scalaris
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2003Co-Authors: Douglas A. Harrison, Robin L. CooperAbstract:The Phoridae is known as ‘scuttle flies’ because they walk in rapid bursts of movement with short pauses between. In this study, larval locomotive behavior and development was characterized in the phorid, Megaselia scalaris. Comparison was made with the well-characterized Fruit Fly Model, Drosophila melanogaster. Developmentally, the rate of maturation was consistently slower for Megaselia than Drosophila. This disparity was exaggerated at lower temperatures, particularly during larval development. In addition to slower growth, movements in Megaselia were also slower, as evidenced by reduced rates of larval body wall contractions and mouth hook movements. Megaselia larvae also displayed a unique behavior of swallowing air when exposed to a small pool of liquid. This permitted floating upon immersion and, therefore, might prevent drowning in the natural environment. The anatomical and physiological properties of a neuromuscular junction in the phorid larvae were also examined. The innervation of the motor nerve terminals on the ventral abdominal muscle (m6) is innervated by Type Ib and Is axons, similar to Drosophila .A s in Drosophila, the Is terminals produce larger excitatory postsynaptic potentials (EPSPs) than the Ib. The amplitudes of the EPSPs in M. scalaris were reduced compared to those of D. melanogaster, but unlike D. melanogaster the EPSPs showed marked facilitation when stimulated with a 20 Hz train. We conclude that there may be differences in synaptic structure of the nerve terminals that could account for the different electrophysiological behaviors. 2003 Elsevier Science Inc. All rights reserved.
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Characterization of development, behavior and neuromuscular physiology in the phorid Fly, Megaselia scalaris
Comparative biochemistry and physiology. Part A Molecular & integrative physiology, 2003Co-Authors: Douglas A. Harrison, Robin L. CooperAbstract:The Phoridae is known as 'scuttle flies' because they walk in rapid bursts of movement with short pauses between. In this study, larval locomotive behavior and development was characterized in the phorid, Megaselia scalaris. Comparison was made with the well-characterized Fruit Fly Model, Drosophila melanogaster. Developmentally, the rate of maturation was consistently slower for Megaselia than Drosophila. This disparity was exaggerated at lower temperatures, particularly during larval development. In addition to slower growth, movements in Megaselia were also slower, as evidenced by reduced rates of larval body wall contractions and mouth hook movements. Megaselia larvae also displayed a unique behavior of swallowing air when exposed to a small pool of liquid. This permitted floating upon immersion and, therefore, might prevent drowning in the natural environment. The anatomical and physiological properties of a neuromuscular junction in the phorid larvae were also examined. The innervation of the motor nerve terminals on the ventral abdominal muscle (m6) is innervated by Type Ib and Is axons, similar to Drosophila. As in Drosophila, the Is terminals produce larger excitatory postsynaptic potentials (EPSPs) than the Ib. The amplitudes of the EPSPs in M. scalaris were reduced compared to those of D. melanogaster, but unlike D. melanogaster the EPSPs showed marked facilitation when stimulated with a 20 Hz train. We conclude that there may be differences in synaptic structure of the nerve terminals that could account for the different electrophysiological behaviors.
Douglas A. Harrison - One of the best experts on this subject based on the ideXlab platform.
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characterization of development behavior and neuromuscular physiology in the phorid Fly megaselia scalaris
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2003Co-Authors: Douglas A. Harrison, Robin L. CooperAbstract:The Phoridae is known as ‘scuttle flies’ because they walk in rapid bursts of movement with short pauses between. In this study, larval locomotive behavior and development was characterized in the phorid, Megaselia scalaris. Comparison was made with the well-characterized Fruit Fly Model, Drosophila melanogaster. Developmentally, the rate of maturation was consistently slower for Megaselia than Drosophila. This disparity was exaggerated at lower temperatures, particularly during larval development. In addition to slower growth, movements in Megaselia were also slower, as evidenced by reduced rates of larval body wall contractions and mouth hook movements. Megaselia larvae also displayed a unique behavior of swallowing air when exposed to a small pool of liquid. This permitted floating upon immersion and, therefore, might prevent drowning in the natural environment. The anatomical and physiological properties of a neuromuscular junction in the phorid larvae were also examined. The innervation of the motor nerve terminals on the ventral abdominal muscle (m6) is innervated by Type Ib and Is axons, similar to Drosophila .A s in Drosophila, the Is terminals produce larger excitatory postsynaptic potentials (EPSPs) than the Ib. The amplitudes of the EPSPs in M. scalaris were reduced compared to those of D. melanogaster, but unlike D. melanogaster the EPSPs showed marked facilitation when stimulated with a 20 Hz train. We conclude that there may be differences in synaptic structure of the nerve terminals that could account for the different electrophysiological behaviors. 2003 Elsevier Science Inc. All rights reserved.
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Characterization of development, behavior and neuromuscular physiology in the phorid Fly, Megaselia scalaris
Comparative biochemistry and physiology. Part A Molecular & integrative physiology, 2003Co-Authors: Douglas A. Harrison, Robin L. CooperAbstract:The Phoridae is known as 'scuttle flies' because they walk in rapid bursts of movement with short pauses between. In this study, larval locomotive behavior and development was characterized in the phorid, Megaselia scalaris. Comparison was made with the well-characterized Fruit Fly Model, Drosophila melanogaster. Developmentally, the rate of maturation was consistently slower for Megaselia than Drosophila. This disparity was exaggerated at lower temperatures, particularly during larval development. In addition to slower growth, movements in Megaselia were also slower, as evidenced by reduced rates of larval body wall contractions and mouth hook movements. Megaselia larvae also displayed a unique behavior of swallowing air when exposed to a small pool of liquid. This permitted floating upon immersion and, therefore, might prevent drowning in the natural environment. The anatomical and physiological properties of a neuromuscular junction in the phorid larvae were also examined. The innervation of the motor nerve terminals on the ventral abdominal muscle (m6) is innervated by Type Ib and Is axons, similar to Drosophila. As in Drosophila, the Is terminals produce larger excitatory postsynaptic potentials (EPSPs) than the Ib. The amplitudes of the EPSPs in M. scalaris were reduced compared to those of D. melanogaster, but unlike D. melanogaster the EPSPs showed marked facilitation when stimulated with a 20 Hz train. We conclude that there may be differences in synaptic structure of the nerve terminals that could account for the different electrophysiological behaviors.
Servane Le Guillouzer - One of the best experts on this subject based on the ideXlab platform.
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ScmR, a Global Regulator of Gene Expression, Quorum Sensing, pH Homeostasis, and Virulence in Burkholderia thailandensis.
Journal of bacteriology, 2020Co-Authors: Servane Le Guillouzer, Marie-christine Groleau, Florian Mauffrey, Eric DézielAbstract:ABSTRACT The nonpathogenic soil saprophyte Burkholderia thailandensis is a member of the Burkholderia pseudomallei/B. thailandensis/B. mallei group, which also comprises the closely related human pathogens B. pseudomallei and Burkholderia mallei responsible for the melioidosis and glanders diseases, respectively. ScmR, a recently identified LysR-type transcriptional regulator in B. thailandensis, acts as a global transcriptional regulator throughout the stationary phase and modulates the production of a wide range of secondary metabolites, including N-acyl-l-homoserine lactones and 4-hydroxy-3-methyl-2-alkylquinolines and virulence in the Caenorhabditis elegans nematode worm host Model, as well as several quorum sensing (QS)-dependent phenotypes. We have investigated the role of ScmR in B. thailandensis strain E264 during the exponential phase. We used RNA sequencing transcriptomic analyses to identify the ScmR regulon, which was compared to the QS-controlled regulon, showing a considerable overlap between the ScmR-regulated genes and those controlled by QS. We characterized several genes modulated by ScmR using quantitative reverse transcription-PCR or mini-CTX-lux transcriptional reporters, including the oxalate biosynthetic gene obc1 required for pH homeostasis, the orphan LuxR-type transcriptional regulator BtaR5-encoding gene, and the bsa (Burkholderia secretion apparatus) type III secretion system genes essential for both B. pseudomallei and B. mallei pathogenicity, as well as the scmR gene itself. We confirmed that the transcription of scmR is under QS control, presumably ensuring fine-tuned modulation of gene expression. Finally, we demonstrated that ScmR influences virulence using the Fruit Fly Model host Drosophila melanogaster. We conclude that ScmR represents a central component of theB. thailandensis QS regulatory network. IMPORTANCE Coordination of the expression of genes associated with bacterial virulence and environmental adaptation is often dependent on quorum sensing (QS). The QS circuitry of the nonpathogenic bacterium Burkholderia thailandensis, widely used as a Model system for the study of the human pathogen Burkholderia pseudomallei, is complex. We found that the LysR-type transcriptional regulator, ScmR, which is highly conserved and involved in the control of virulence/survival factors in the Burkholderia genus, is a global regulator mediating gene expression through the multiple QS systems coexisting in B. thailandensis, as well as QS independently. We conclude that ScmR represents a key QS modulatory network element, ensuring tight regulation of the transcription of QS-controlled genes, particularly those required for acclimatization to the environment.
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ScmR, a global regulator of gene expression, quorum sensing, pH homeostasis, and virulence in Burkholderia thailandensis
2019Co-Authors: Servane Le Guillouzer, Marie-christine Groleau, Florian Mauffrey, Eric DézielAbstract:Abstract The nonpathogenic soil saprophyte Burkholderia thailandensis is a member of the Burkholderia pseudomallei-thailandensis-mallei (Bptm) group, which also comprises the closely related human pathogens Burkholderia pseudomallei and Burkholderia mallei responsible for the diseases melioidosis and glanders, respectively. ScmR, a recently identified LysR-type transcriptional regulator (LTTR) in B. thailandensis acts as a global transcriptional regulator throughout the stationary phase, and modulates the production of a wide range of secondary metabolites, including N-acyl-L-homoserine lactones (AHLs) and 4-hydroxy-3-methyl-2-alkylquinoline (HMAQ), virulence in the Model host Caenorhabditis elegans, as well as several quorum sensing (QS)-dependent phenotypes. We have investigated the role of ScmR in B. thailandensis strain E264 during the exponential phase. We used RNA-Sequencing (RNA-Seq) transcriptomic analyses to identify the ScmR regulon, which was compared to the QS-controlled regulon, showing a considerable overlap between the ScmR-regulated genes and those controlled by QS. We characterized several genes modulated by ScmR, using quantitative reverse transcription-PCR (qRT-PCR) or mini-CTX-lux transcriptional reporters, including the oxalate biosynthetic gene obc1 required for pH homeostasis, the orphan LuxR-type transcriptional regulator BtaR5-encoding gene, the bsa (Burkholderia secretion apparatus) type III secretion system (T3SS) genes essential for both B. pseudomallei and B. mallei pathogenicity, as well as the scmR gene itself. We confirmed that the transcription of scmR is under QS control, presumably ensuring fine-tuned modulation of gene expression. Finally, we demonstrate that ScmR influences virulence using the Fruit Fly Model host Drosophila melanogaster. We conclude that ScmR represents a central component of the B. thailandensis QS regulatory network. Importance Coordination of the expression of genes associated with bacterial virulence and environmental adaptation is often dependent on quorum sensing (QS). The QS circuitry of the nonpathogenic bacterium Burkholderia thailandensis, which is widely used as a Model system for the study of the human pathogen Burkholderia pseudomallei, is complex. We found that the recently identified LysR-type transcriptional regulator (LTTR), ScmR, which is highly conserved and involved in the control of virulence/survival factors in the Burkholderia genus, is a global regulator mediating gene expression through the multiple QS systems coexisting in B. thailandensis, as well as independently of QS. We conclude that ScmR represents a key QS modulatory network element, ensuring tight regulation of the transcription of QS-controlled genes, particularly those required for acclimatization to the environment.
Corrado Caggese - One of the best experts on this subject based on the ideXlab platform.
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Characterization of Drosophila ATPsynC mutants as a new Model of mitochondrial ATP synthase disorders.
PloS one, 2018Co-Authors: Domenica Lovero, Luca Giordano, René Massimiliano Marsano, Alvaro Sanchez-martinez, Hadi Boukhatmi, Maik Drechsler, Marta Oliva, Alexander J. Whitworth, Damiano Porcelli, Corrado CaggeseAbstract:Mitochondrial disorders associated with genetic defects of the ATP synthase are among the most deleterious diseases of the neuromuscular system that primarily manifest in newborns. Nevertheless, the number of established animal Models for the elucidation of the molecular mechanisms behind such pathologies is limited. In this paper, we target the Drosophila melanogaster gene encoding for the ATP synthase subunit c, ATPsynC, in order to create a Fruit Fly Model for investigating defects in mitochondrial bioenergetics and to better understand the comprehensive pathological spectrum associated with mitochondrial ATP synthase dysfunctions. Using P-element and EMS mutagenesis, we isolated a set of mutations showing a wide range of effects, from larval lethality to complex pleiotropic phenotypes encompassing developmental delay, early adult lethality, hypoactivity, sterility, hypofertility, aberrant male courtship behavior, locomotor defects and aberrant gonadogenesis. ATPsynC mutations impair ATP synthesis and mitochondrial morphology, and represent a powerful toolkit for the screening of genetic modifiers that can lead to potential therapeutic solutions. Furthermore, the molecular characterization of ATPsynC mutations allowed us to better understand the genetics of the ATPsynC locus and to define three broad pathological consequences of mutations affecting the mitochondrial ATP synthase functionality in Drosophila: i) pre-adult lethality; ii) multi-trait pathology accompanied by early adult lethality; iii) multi-trait adult pathology. We finally predict plausible parallelisms with genetic defects of mitochondrial ATP synthase in humans.
