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Matthew K Waldor - One of the best experts on this subject based on the ideXlab platform.

  • genetic analysis of the role of the conserved inner membrane protein cvpa in ehec resistance to deoxycholate
    Journal of Bacteriology, 2021
    Co-Authors: Alyson R Warr, Rachel T Giorgio, Matthew K Waldor
    Abstract:

    The function of cvpA, a Bacterial gene predicted to encode an inner membrane protein, is largely unknown. Early studies in E. coli linked cvpA to Colicin V secretion and recent work revealed that it is required for robust intestinal colonization by diverse enteric pathogens. In enterohemorrhagic E. coli (EHEC), cvpA is required for resistance to the bile salt deoxycholate (DOC). Here, we carried out genome-scale transposon-insertion mutagenesis and spontaneous suppressor analysis to uncover cvpA's genetic interactions and identify common pathways that rescue the sensitivity of a ΔcvpA EHEC mutant to DOC. These screens demonstrated that mutations predicted to activate the σE-mediated extracytoplasmic stress response bypass the ΔcvpA mutant's susceptibility to DOC. Consistent with this idea, we found that deletions in rseA and msbB and direct overexpression of rpoE restored DOC resistance to the ΔcvpA mutant. Analysis of the distribution of CvpA homologs revealed that this inner membrane protein is conserved across diverse Bacterial Phyla, in both enteric and non-enteric bacteria that are not exposed to bile. Together, our findings suggest that CvpA plays a role in cell envelope homeostasis in response to DOC and similar stress stimuli in diverse Bacterial species.IMPORTANCE Several enteric pathogens, including Enterohemorrhagic E. coli (EHEC), require CvpA to robustly colonize the intestine. This inner membrane protein is also important for secretion of a colicin and EHEC resistance to the bile salt deoxycholate (DOC), but its function is unknown. Genetic analyses carried out here showed that activation of the σE-mediated extracytoplasmic stress response restored the resistance of a cvpA mutant to DOC, suggesting that CvpA plays a role in cell envelope homeostasis. The conservation of CvpA across diverse Bacterial Phyla suggests that this membrane protein facilitates cell envelope homeostasis in response to varied cell envelope perturbations.

  • genetic analysis of the role of the conserved inner membrane protein cvpa in enterohemorrhagic escherichia coli resistance to deoxycholate
    Journal of Bacteriology, 2020
    Co-Authors: Alyson R Warr, Rachel T Giorgio, Matthew K Waldor
    Abstract:

    ABSTRACT The function of cvpA, a Bacterial gene predicted to encode an inner membrane protein, is largely unknown. Early studies in Escherichia coli linked cvpA to colicin V secretion, and recent work revealed that it is required for robust intestinal colonization by diverse enteric pathogens. In enterohemorrhagic E. coli (EHEC) strains, cvpA is required for resistance to the bile salt deoxycholate (DOC). Here, we carried out genome scale transposon insertion (TIS) mutagenesis and spontaneous suppressor analysis to uncover the genetic interactions of cvpA and identify common pathways that rescue the sensitivity of a ΔcvpA EHEC mutant to DOC. These screens demonstrated that mutations predicted to activate the σE-mediated extracytoplasmic stress response bypass the ΔcvpA mutant’s susceptibility to DOC. Consistent with this idea, we found that deletions in rseA and msbB and direct overexpression of rpoE restored DOC resistance to the ΔcvpA mutant. Analysis of the distribution of CvpA homologs revealed that this inner membrane protein is conserved across diverse Bacterial Phyla in both enteric and nonenteric bacteria that are not exposed to bile. Together, our findings suggest that CvpA plays a role in cell envelope homeostasis in response to DOC and similar stress stimuli in diverse Bacterial species. IMPORTANCE Several enteric pathogens, including enterohemorrhagic E. coli (EHEC) strains, require CvpA to robustly colonize the intestine. This inner membrane protein is also important for secretion of a colicin and for EHEC resistance to the bile salt deoxycholate (DOC), but its function is unknown. Genetic analyses carried out here showed that activation of the σE-mediated extracytoplasmic stress response restored the resistance of a cvpA mutant to DOC, suggesting that CvpA plays a role in cell envelope homeostasis. The conservation of CvpA across diverse Bacterial Phyla suggests that this membrane protein facilitates cell envelope homeostasis in response to varied cell envelope perturbations.

  • genetic analyses link the conserved inner membrane protein cvpa to the σeextracytoplasmic stress response
    bioRxiv, 2020
    Co-Authors: Alyson R Warr, Rachel T Giorgio, Matthew K Waldor
    Abstract:

    The function of cvpA, a Bacterial gene predicted to encode an inner membrane protein, is largely unknown. Early studies in E. coli linked cvpA to Colicin V secretion and recent work revealed that it is required for robust intestinal colonization by diverse enteric pathogens. In enterohemorrhagic E. coli (EHEC), cvpA is required for resistance to the bile salt deoxycholate (DOC). Here, we carried out genome-scale transposon-insertion mutagenesis and spontaneous suppressor analysis to uncover cvpAs genetic interactions and identify common pathways that rescue the sensitivity of a {Delta}cvpA EHEC mutant to DOC. Collectively, these screens led to the hypothesis that the {Delta}cvpA mutant is impaired in its capacity to activate the {sigma}E-mediated stress response. This idea was supported by showing that mutations that activate {sigma}E, either indirectly or through its direct overexpression, can restore the {Delta}cvpA mutants resistance to DOC. Analysis of the distribution of CvpA homologs revealed that this inner membrane protein is conserved across Bacterial Phyla, in both enteric and non-enteric bacteria that are not exposed to bile. Together, our findings suggest that CvpA may function in triggering activation of the {sigma}E stress response pathway in response to DOC as well as additional stimuli. ImportanceSeveral enteric pathogens, including Enterohemorrhagic E. coli (EHEC), require cvpA to robustly colonize the intestine. This inner membrane is also important for secretion of a colicin and EHEC resistance to the bile salt deoxycholate, but its function is unknown. Genetic analyses carried out here suggest that cvpA is required to trigger the {sigma}E stress response pathway in response to deoxycholate. Since CvpA is conserved across diverse Bacterial Phyla, we propose that this inner membrane protein is important for activation of this stress response pathway in response to diverse perturbations of the cell envelope.

Richard A. Long - One of the best experts on this subject based on the ideXlab platform.

  • phylogenetic structure of Bacterial assemblages co occurring with ostreopsis cf ovata bloom
    Harmful Algae, 2016
    Co-Authors: Silvana Vanucci, Flavio Guidi, Rossella Pistocchi, Richard A. Long
    Abstract:

    Extensive blooms of the toxic epiphytic/benthic dinoflagellate Ostreopsis cf. ovata are being reported with increasing frequency and spatial distribution in temperate coastal regions including the Mediterranean. These blooms are of human and environmental health concern due to the production of isobaric palytoxin and a wide range of ovatoxins by Ostreopsis cf. ovata. Bacterial-microalgal interactions are important regulators in algal bloom dynamics and potentially toxin dynamics. This study investigated the Bacterial assemblages co-occurring with O. cf. ovata (OA) and from ambient seawaters (SW) during the early and peak phases of bloom development in NW Adriatic Sea. Fractions of the Bacterial assemblages co-occurring with O. cf. ovata (OA) and more closely associated to the mucilage layer (LA) embedding O. cf. ovata cells were also reported. In total, 14 Bacterial Phyla were detected by targeted 454 pyrosequencing of the 16S rRNA gene. The dominant Bacterial Phyla in the OA assemblages were Proteobacteria and Bacteroidetes; while at the class level, Alphaproteobacteria were the most abundant (83 and 66%, relative abundance, early and peak bloom phases), followed by Flavobacteria (7 and 19%, early and peak phases). Actinobacteria and Cyanobacteria were of minor importance (<5% of the relative Bacterial abundance each). Gammaproteobacteria showed a notably presence in OA assemblage only at the early phase of the bloom (genus Haliea, 13%). The Alphaproteobacteria were predominately composed by the genera Ruegeria, Jannaschia and Erythrobacter which represented about half of the total phylotypes’ contribution of OA at both early and peak phases of the O. cf. ovata bloom, suggesting interactions between this consortium and the microalga. Moreover, the highest contribution of Ruegeria (30% of the total phylotypes) was observed at the early phase of the bloom in LA assemblage. Microbial assemblages associated with the ambient seawaters while being also dominated by Alphaproteobacteria and Flavobacteria were partially distinct from those associated with O. cf. ovata due to the presence of genera almost not retrieved in the latter assemblages.

  • Phylogenetic structure of Bacterial assemblages co-occurring with Ostreopsis cf. ovata bloom
    Harmful algae, 2016
    Co-Authors: Silvana Vanucci, Flavio Guidi, Rossella Pistocchi, Richard A. Long
    Abstract:

    Extensive blooms of the toxic epiphytic/benthic dinoflagellate Ostreopsis cf. ovata are being reported with increasing frequency and spatial distribution in temperate coastal regions including the Mediterranean. These blooms are of human and environmental health concern due to the production of isobaric palytoxin and a wide range of ovatoxins by Ostreopsis cf. ovata. Bacterial-microalgal interactions are important regulators in algal bloom dynamics and potentially toxin dynamics. This study investigated the Bacterial assemblages co-occurring with O. cf. ovata (OA) and from ambient seawaters (SW) during the early and peak phases of bloom development in NW Adriatic Sea. Fractions of the Bacterial assemblages co-occurring with O. cf. ovata (OA) and more closely associated to the mucilage layer (LA) embedding O. cf. ovata cells were also reported. In total, 14 Bacterial Phyla were detected by targeted 454 pyrosequencing of the 16S rRNA gene. The dominant Bacterial Phyla in the OA assemblages were Proteobacteria and Bacteroidetes; while at the class level, Alphaproteobacteria were the most abundant (83 and 66%, relative abundance, early and peak bloom phases), followed by Flavobacteria (7 and 19%, early and peak phases). Actinobacteria and Cyanobacteria were of minor importance (

Alyson R Warr - One of the best experts on this subject based on the ideXlab platform.

  • genetic analysis of the role of the conserved inner membrane protein cvpa in ehec resistance to deoxycholate
    Journal of Bacteriology, 2021
    Co-Authors: Alyson R Warr, Rachel T Giorgio, Matthew K Waldor
    Abstract:

    The function of cvpA, a Bacterial gene predicted to encode an inner membrane protein, is largely unknown. Early studies in E. coli linked cvpA to Colicin V secretion and recent work revealed that it is required for robust intestinal colonization by diverse enteric pathogens. In enterohemorrhagic E. coli (EHEC), cvpA is required for resistance to the bile salt deoxycholate (DOC). Here, we carried out genome-scale transposon-insertion mutagenesis and spontaneous suppressor analysis to uncover cvpA's genetic interactions and identify common pathways that rescue the sensitivity of a ΔcvpA EHEC mutant to DOC. These screens demonstrated that mutations predicted to activate the σE-mediated extracytoplasmic stress response bypass the ΔcvpA mutant's susceptibility to DOC. Consistent with this idea, we found that deletions in rseA and msbB and direct overexpression of rpoE restored DOC resistance to the ΔcvpA mutant. Analysis of the distribution of CvpA homologs revealed that this inner membrane protein is conserved across diverse Bacterial Phyla, in both enteric and non-enteric bacteria that are not exposed to bile. Together, our findings suggest that CvpA plays a role in cell envelope homeostasis in response to DOC and similar stress stimuli in diverse Bacterial species.IMPORTANCE Several enteric pathogens, including Enterohemorrhagic E. coli (EHEC), require CvpA to robustly colonize the intestine. This inner membrane protein is also important for secretion of a colicin and EHEC resistance to the bile salt deoxycholate (DOC), but its function is unknown. Genetic analyses carried out here showed that activation of the σE-mediated extracytoplasmic stress response restored the resistance of a cvpA mutant to DOC, suggesting that CvpA plays a role in cell envelope homeostasis. The conservation of CvpA across diverse Bacterial Phyla suggests that this membrane protein facilitates cell envelope homeostasis in response to varied cell envelope perturbations.

  • genetic analysis of the role of the conserved inner membrane protein cvpa in enterohemorrhagic escherichia coli resistance to deoxycholate
    Journal of Bacteriology, 2020
    Co-Authors: Alyson R Warr, Rachel T Giorgio, Matthew K Waldor
    Abstract:

    ABSTRACT The function of cvpA, a Bacterial gene predicted to encode an inner membrane protein, is largely unknown. Early studies in Escherichia coli linked cvpA to colicin V secretion, and recent work revealed that it is required for robust intestinal colonization by diverse enteric pathogens. In enterohemorrhagic E. coli (EHEC) strains, cvpA is required for resistance to the bile salt deoxycholate (DOC). Here, we carried out genome scale transposon insertion (TIS) mutagenesis and spontaneous suppressor analysis to uncover the genetic interactions of cvpA and identify common pathways that rescue the sensitivity of a ΔcvpA EHEC mutant to DOC. These screens demonstrated that mutations predicted to activate the σE-mediated extracytoplasmic stress response bypass the ΔcvpA mutant’s susceptibility to DOC. Consistent with this idea, we found that deletions in rseA and msbB and direct overexpression of rpoE restored DOC resistance to the ΔcvpA mutant. Analysis of the distribution of CvpA homologs revealed that this inner membrane protein is conserved across diverse Bacterial Phyla in both enteric and nonenteric bacteria that are not exposed to bile. Together, our findings suggest that CvpA plays a role in cell envelope homeostasis in response to DOC and similar stress stimuli in diverse Bacterial species. IMPORTANCE Several enteric pathogens, including enterohemorrhagic E. coli (EHEC) strains, require CvpA to robustly colonize the intestine. This inner membrane protein is also important for secretion of a colicin and for EHEC resistance to the bile salt deoxycholate (DOC), but its function is unknown. Genetic analyses carried out here showed that activation of the σE-mediated extracytoplasmic stress response restored the resistance of a cvpA mutant to DOC, suggesting that CvpA plays a role in cell envelope homeostasis. The conservation of CvpA across diverse Bacterial Phyla suggests that this membrane protein facilitates cell envelope homeostasis in response to varied cell envelope perturbations.

  • genetic analyses link the conserved inner membrane protein cvpa to the σeextracytoplasmic stress response
    bioRxiv, 2020
    Co-Authors: Alyson R Warr, Rachel T Giorgio, Matthew K Waldor
    Abstract:

    The function of cvpA, a Bacterial gene predicted to encode an inner membrane protein, is largely unknown. Early studies in E. coli linked cvpA to Colicin V secretion and recent work revealed that it is required for robust intestinal colonization by diverse enteric pathogens. In enterohemorrhagic E. coli (EHEC), cvpA is required for resistance to the bile salt deoxycholate (DOC). Here, we carried out genome-scale transposon-insertion mutagenesis and spontaneous suppressor analysis to uncover cvpAs genetic interactions and identify common pathways that rescue the sensitivity of a {Delta}cvpA EHEC mutant to DOC. Collectively, these screens led to the hypothesis that the {Delta}cvpA mutant is impaired in its capacity to activate the {sigma}E-mediated stress response. This idea was supported by showing that mutations that activate {sigma}E, either indirectly or through its direct overexpression, can restore the {Delta}cvpA mutants resistance to DOC. Analysis of the distribution of CvpA homologs revealed that this inner membrane protein is conserved across Bacterial Phyla, in both enteric and non-enteric bacteria that are not exposed to bile. Together, our findings suggest that CvpA may function in triggering activation of the {sigma}E stress response pathway in response to DOC as well as additional stimuli. ImportanceSeveral enteric pathogens, including Enterohemorrhagic E. coli (EHEC), require cvpA to robustly colonize the intestine. This inner membrane is also important for secretion of a colicin and EHEC resistance to the bile salt deoxycholate, but its function is unknown. Genetic analyses carried out here suggest that cvpA is required to trigger the {sigma}E stress response pathway in response to deoxycholate. Since CvpA is conserved across diverse Bacterial Phyla, we propose that this inner membrane protein is important for activation of this stress response pathway in response to diverse perturbations of the cell envelope.

Silvana Vanucci - One of the best experts on this subject based on the ideXlab platform.

  • phylogenetic structure of Bacterial assemblages co occurring with ostreopsis cf ovata bloom
    Harmful Algae, 2016
    Co-Authors: Silvana Vanucci, Flavio Guidi, Rossella Pistocchi, Richard A. Long
    Abstract:

    Extensive blooms of the toxic epiphytic/benthic dinoflagellate Ostreopsis cf. ovata are being reported with increasing frequency and spatial distribution in temperate coastal regions including the Mediterranean. These blooms are of human and environmental health concern due to the production of isobaric palytoxin and a wide range of ovatoxins by Ostreopsis cf. ovata. Bacterial-microalgal interactions are important regulators in algal bloom dynamics and potentially toxin dynamics. This study investigated the Bacterial assemblages co-occurring with O. cf. ovata (OA) and from ambient seawaters (SW) during the early and peak phases of bloom development in NW Adriatic Sea. Fractions of the Bacterial assemblages co-occurring with O. cf. ovata (OA) and more closely associated to the mucilage layer (LA) embedding O. cf. ovata cells were also reported. In total, 14 Bacterial Phyla were detected by targeted 454 pyrosequencing of the 16S rRNA gene. The dominant Bacterial Phyla in the OA assemblages were Proteobacteria and Bacteroidetes; while at the class level, Alphaproteobacteria were the most abundant (83 and 66%, relative abundance, early and peak bloom phases), followed by Flavobacteria (7 and 19%, early and peak phases). Actinobacteria and Cyanobacteria were of minor importance (<5% of the relative Bacterial abundance each). Gammaproteobacteria showed a notably presence in OA assemblage only at the early phase of the bloom (genus Haliea, 13%). The Alphaproteobacteria were predominately composed by the genera Ruegeria, Jannaschia and Erythrobacter which represented about half of the total phylotypes’ contribution of OA at both early and peak phases of the O. cf. ovata bloom, suggesting interactions between this consortium and the microalga. Moreover, the highest contribution of Ruegeria (30% of the total phylotypes) was observed at the early phase of the bloom in LA assemblage. Microbial assemblages associated with the ambient seawaters while being also dominated by Alphaproteobacteria and Flavobacteria were partially distinct from those associated with O. cf. ovata due to the presence of genera almost not retrieved in the latter assemblages.

  • Phylogenetic structure of Bacterial assemblages co-occurring with Ostreopsis cf. ovata bloom
    Harmful algae, 2016
    Co-Authors: Silvana Vanucci, Flavio Guidi, Rossella Pistocchi, Richard A. Long
    Abstract:

    Extensive blooms of the toxic epiphytic/benthic dinoflagellate Ostreopsis cf. ovata are being reported with increasing frequency and spatial distribution in temperate coastal regions including the Mediterranean. These blooms are of human and environmental health concern due to the production of isobaric palytoxin and a wide range of ovatoxins by Ostreopsis cf. ovata. Bacterial-microalgal interactions are important regulators in algal bloom dynamics and potentially toxin dynamics. This study investigated the Bacterial assemblages co-occurring with O. cf. ovata (OA) and from ambient seawaters (SW) during the early and peak phases of bloom development in NW Adriatic Sea. Fractions of the Bacterial assemblages co-occurring with O. cf. ovata (OA) and more closely associated to the mucilage layer (LA) embedding O. cf. ovata cells were also reported. In total, 14 Bacterial Phyla were detected by targeted 454 pyrosequencing of the 16S rRNA gene. The dominant Bacterial Phyla in the OA assemblages were Proteobacteria and Bacteroidetes; while at the class level, Alphaproteobacteria were the most abundant (83 and 66%, relative abundance, early and peak bloom phases), followed by Flavobacteria (7 and 19%, early and peak phases). Actinobacteria and Cyanobacteria were of minor importance (

Leonardo Erijman - One of the best experts on this subject based on the ideXlab platform.

  • industrial activated sludge exhibit unique Bacterial community composition at high taxonomic ranks
    Water Research, 2013
    Co-Authors: Federico Matias Ibarbalz, Eva Lucia Margarita Figuerola, Leonardo Erijman
    Abstract:

    Biological degradation of domestic and industrial wastewater by activated sludge depends on a common process of separation of the diverse self-assembled and self-sustained microbial flocs from the treated wastewater. Previous surveys of Bacterial communities indicated the presence of a common core of Bacterial Phyla in municipal activated sludge, an observation consistent with the concept of ecological coherence of high taxonomic ranks. The aim of this work was to test whether this critical feature brings about a common pattern of abundance distribution of high Bacterial taxa in industrial and domestic activated sludge, and to relate the Bacterial community structure of industrial activated sludge with relevant operational parameters. We have applied 454 pyrosequencing of 16S rRNA genes to evaluate Bacterial communities in full-scale biological wastewater treatment plants sampled at different times, including seven systems treating wastewater from different industries and one plant that treats domestic wastewater, and compared our datasets with the data from municipal wastewater treatment plants obtained by three different laboratories. We observed that each industrial activated sludge system exhibited a unique Bacterial community composition, which is clearly distinct from the common profile of Bacterial Phyla or classes observed in municipal plants. The influence of process parameters on the Bacterial community structure was evaluated using constrained analysis of principal coordinates (CAP). Part of the differences in the Bacterial community structure between industrial wastewater treatment systems were explained by dissolved oxygen and pH. Despite the ecological relevance of floc formation for the assembly of Bacterial communities in activated sludge, the wastewater characteristics are likely to be the major determinant that drives Bacterial composition at high taxonomic ranks.