The Experts below are selected from a list of 8982 Experts worldwide ranked by ideXlab platform
Nicole C. Roy - One of the best experts on this subject based on the ideXlab platform.
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live faecalibacterium prausnitzii induces greater tlr2 and tlr2 6 activation than the dead bacterium in an apical anaerobic co culture system
Cellular Microbiology, 2018Co-Authors: Eva Maier, Rachel C. Anderson, Eric Altermann, Nicole C. RoyAbstract:Inappropriate activation of intestinal innate immune receptors, such as toll-like receptors (TLRs), by pathogenic bacteria is linked to chronic inflammation. In contrast, a "tonic" level of TLR activation by commensal bacteria is required for intestinal homeostasis. A technical challenge when studying this activation in vitro is the co-culturing of oxygen-requiring mammalian cells with obligate anaerobic commensal bacteria. To overcome this, we used a novel apical anaerobic co-culture system to successfully adapt a TLR activation assay to be conducted in conditions optimised for both cell types. Live Faecalibacterium prausnitzii, an abundant obligate Anaerobe of the colonic microbiota, induced higher TLR2 and TLR2/6 activation than the dead bacterium. This enhanced TLR induction by live F. prausnitzii, which until now has not previously been described, may contribute to maintenance of gastrointestinal homeostasis. This highlights the importance of using physiologically relevant co-culture systems to decipher the mechanisms of action of live obligate Anaerobes.
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live faecalibacterium prausnitzii in an apical anaerobic model of the intestinal epithelial barrier
Cellular Microbiology, 2015Co-Authors: Rachel C. Anderson, Dulantha Ulluwishewa, Wayne Young, Warren C Mcnabb, Peter Van Baarlen, Paul J Moughan, Jerry M Wells, Nicole C. RoyAbstract:Faecalibacterium prausnitzii, an abundant member of the human commensal microbiota, has been proposed to have a protective role in the intestine. However, it is an obligate Anaerobe, difficult to co-culture in viable form with oxygen-requiring intestinal cells. To overcome this limitation, a unique apical anaerobic model of the intestinal barrier, which enabled co-culture of live obligate Anaerobes with the human intestinal cell line Caco-2, was developed. Caco-2 cells remained viable and maintained an intact barrier for at least 12?h, consistent with gene expression data, which suggested Caco-2 cells had adapted to survive in an oxygen-reduced atmosphere. Live F.?prausnitzii cells, but not ultraviolet (UV)-killed F.?prausnitzii, increased the permeability of mannitol across the epithelial barrier. Gene expression analysis showed inflammatory mediators to be expressed at lower amounts in Caco-2 cells exposed to live F.?prausnitzii than UV-killed F.?prausnitzii, This, consistent with previous reports, implies that live F.?prausnitzii produces an anti-inflammatory compound in the culture supernatant, demonstrating the value of a physiologically relevant co-culture system that allows obligate anaerobic bacteria to remain viable.
Solange Oliveira - One of the best experts on this subject based on the ideXlab platform.
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structure of a dioxygen reduction enzyme from desulfovibrio gigas
Nature Structural & Molecular Biology, 2000Co-Authors: Carlos Frazao, Gabriela G F Silva, Claudio M Gomes, Pedro M Matias, Ricardo Coelho, L C Sieker, S Macedo, Ming Y Liu, Solange OliveiraAbstract:Desulfovibrio gigas is a strict Anaerobe that contains a well-characterized metabolic pathway that enables it to survive transient contacts with oxygen. The terminal enzyme in this pathway, rubredoxin:oxygen oxidoreductase (ROO) reduces oxygen to water in a direct and safe way. The 2.5 A resolution crystal structure of ROO shows that each monomer of this homodimeric enzyme consists of a novel combination of two domains, a flavodoxin-like domain and a Zn-β-lactamase-like domain that contains a di-iron center for dioxygen reduction. This is the first structure of a member of a superfamily of enzymes widespread in strict and facultative Anaerobes, indicating its broad physiological significance.
Laetitia Pieulle - One of the best experts on this subject based on the ideXlab platform.
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Biochemical Function, Molecular Structure and Evolution of an Atypical Thioredoxin Reductase from Desulfovibrio vulgaris
Frontiers in Microbiology, 2017Co-Authors: Odile Valette, Tam T. T. Tran, Christine Cavazza, Elodie Caudeville, Gaël Brasseur, Alain Dolla, Emmanuel Talla, Laetitia PieulleAbstract:Thioredoxin reductase (TR) regulates the intracellular redox environment by reducing thioredoxin (Trx). In Anaerobes, recent findings indicate that the Trx redox network is implicated in the global redox regulation of metabolism but also actively participates in protecting cells against O2. In the Anaerobe Desulfovibrio vulgaris Hildenborough (DvH), there is an intriguing redundancy of the Trx system which includes a classical system using NADPH as electron source, a non-canonical system using NADH and an isolated TR (DvTRi). The functionality of DvTRi was questioned due to its lack of reactivity with DvTrxs. Structural analysis shows that DvTRi is a NAD(P)H-independent TR but its reducer needs still to be identified. Moreover, DvTRi reduced by an artificial electron source is able to reduce in turn DvTrx1 and complexation experiments demonstrate a direct interaction between DvTRi and DvTrx1. The deletion mutant tri exhibits a higher sensitivity to disulfide stress and the gene tri is upregulated by O2 exposure. Having DvTRi in addition to DvTR1 as electron source for reducing DvTrx1 must be an asset to combat oxidative stress. Large-scale phylogenomics analyses show that TRi homologs are confined within the Anaerobes. All TRi proteins displayed a conserved TQ/NGK motif instead of the HRRD motif, which is selective for the binding of the 2'-phosphate group of NADPH. The evolutionary history of TRs indicates that tr1 is the common gene ancestor in prokaryotes, affected by both gene duplications and horizontal gene events, therefore leading to the appearance of TRi through subfunctionalization over the evolutionary time.
Dulantha Ulluwishewa - One of the best experts on this subject based on the ideXlab platform.
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live faecalibacterium prausnitzii in an apical anaerobic model of the intestinal epithelial barrier
Cellular Microbiology, 2015Co-Authors: Rachel C. Anderson, Dulantha Ulluwishewa, Wayne Young, Warren C Mcnabb, Peter Van Baarlen, Paul J Moughan, Jerry M Wells, Nicole C. RoyAbstract:Faecalibacterium prausnitzii, an abundant member of the human commensal microbiota, has been proposed to have a protective role in the intestine. However, it is an obligate Anaerobe, difficult to co-culture in viable form with oxygen-requiring intestinal cells. To overcome this limitation, a unique apical anaerobic model of the intestinal barrier, which enabled co-culture of live obligate Anaerobes with the human intestinal cell line Caco-2, was developed. Caco-2 cells remained viable and maintained an intact barrier for at least 12?h, consistent with gene expression data, which suggested Caco-2 cells had adapted to survive in an oxygen-reduced atmosphere. Live F.?prausnitzii cells, but not ultraviolet (UV)-killed F.?prausnitzii, increased the permeability of mannitol across the epithelial barrier. Gene expression analysis showed inflammatory mediators to be expressed at lower amounts in Caco-2 cells exposed to live F.?prausnitzii than UV-killed F.?prausnitzii, This, consistent with previous reports, implies that live F.?prausnitzii produces an anti-inflammatory compound in the culture supernatant, demonstrating the value of a physiologically relevant co-culture system that allows obligate anaerobic bacteria to remain viable.
Rachel C. Anderson - One of the best experts on this subject based on the ideXlab platform.
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live faecalibacterium prausnitzii induces greater tlr2 and tlr2 6 activation than the dead bacterium in an apical anaerobic co culture system
Cellular Microbiology, 2018Co-Authors: Eva Maier, Rachel C. Anderson, Eric Altermann, Nicole C. RoyAbstract:Inappropriate activation of intestinal innate immune receptors, such as toll-like receptors (TLRs), by pathogenic bacteria is linked to chronic inflammation. In contrast, a "tonic" level of TLR activation by commensal bacteria is required for intestinal homeostasis. A technical challenge when studying this activation in vitro is the co-culturing of oxygen-requiring mammalian cells with obligate anaerobic commensal bacteria. To overcome this, we used a novel apical anaerobic co-culture system to successfully adapt a TLR activation assay to be conducted in conditions optimised for both cell types. Live Faecalibacterium prausnitzii, an abundant obligate Anaerobe of the colonic microbiota, induced higher TLR2 and TLR2/6 activation than the dead bacterium. This enhanced TLR induction by live F. prausnitzii, which until now has not previously been described, may contribute to maintenance of gastrointestinal homeostasis. This highlights the importance of using physiologically relevant co-culture systems to decipher the mechanisms of action of live obligate Anaerobes.
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live faecalibacterium prausnitzii in an apical anaerobic model of the intestinal epithelial barrier
Cellular Microbiology, 2015Co-Authors: Rachel C. Anderson, Dulantha Ulluwishewa, Wayne Young, Warren C Mcnabb, Peter Van Baarlen, Paul J Moughan, Jerry M Wells, Nicole C. RoyAbstract:Faecalibacterium prausnitzii, an abundant member of the human commensal microbiota, has been proposed to have a protective role in the intestine. However, it is an obligate Anaerobe, difficult to co-culture in viable form with oxygen-requiring intestinal cells. To overcome this limitation, a unique apical anaerobic model of the intestinal barrier, which enabled co-culture of live obligate Anaerobes with the human intestinal cell line Caco-2, was developed. Caco-2 cells remained viable and maintained an intact barrier for at least 12?h, consistent with gene expression data, which suggested Caco-2 cells had adapted to survive in an oxygen-reduced atmosphere. Live F.?prausnitzii cells, but not ultraviolet (UV)-killed F.?prausnitzii, increased the permeability of mannitol across the epithelial barrier. Gene expression analysis showed inflammatory mediators to be expressed at lower amounts in Caco-2 cells exposed to live F.?prausnitzii than UV-killed F.?prausnitzii, This, consistent with previous reports, implies that live F.?prausnitzii produces an anti-inflammatory compound in the culture supernatant, demonstrating the value of a physiologically relevant co-culture system that allows obligate anaerobic bacteria to remain viable.