The Experts below are selected from a list of 276 Experts worldwide ranked by ideXlab platform
Jônatas Santos Abrahão - One of the best experts on this subject based on the ideXlab platform.
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Tupanvirus-infected amoebas are induced to aggregate with uninfected cells promoting viral dissemination
Scientific Reports, 2019Co-Authors: Graziele Oliveira, Lorena Silva, Thiago Leão, Said Mougari, Flávio Guimarães Da Fonseca, Erna Geessien Kroon, Bernard La Scola, Jônatas Santos AbrahãoAbstract:The discovery of giant viruses in the last years has fascinated the scientific community due to virus particles size and genome complexity. Among such fantastic discoveries, we have recently described tupanviruses, which particles present a long tail, and has a genome that contains the most complete set of translation-related genes ever reported in the known virosphere. Here we describe a new kind of virus-host interaction involving tupanvirus. We observed that tupanvirus-infected amoebas were induced to aggregate with uninfected cells, promoting viral dissemination and forming giant host cell bunches. Even after mechanical breakdown of bunches, amoebas reaggregated within a few minutes. This remarkable interaction between infected and uninfected cells seems to be promoted by the expression of a mannose receptor gene. Our investigations demonstrate that the pre-treatment of amoebas with free mannose inhibits the formation of bunches, in a concentration-dependent manner, suggesting that amoebal-bunch formation correlates with mannose receptor gene expression. Finally, our data suggest that bunch-forming cells are able to interact with uninfected cells promoting the dissemination and increase of tupanvirus progeny. The recent discovery of tupanvirus, one of the largest and most complex viruses isolated to date, has reinforced the structural and genomic complexity of the giant viruses 1. Tupanviruses have been isolated from soda lakes, known as an extreme aquatic environments, and from ocean sediments collected at a depth of 3000 meters (m) 1,2. Phylogenetic analyses have shown the clustering of the tupanvirus with members of the family Mimiviridae. However, there are many peculiarities that make the tupanviruses unique entities in the known virosphere. Since its first observation, tupanviruses showed remarkable morphological characteristics; it has optically visible particles that average about 1.2 µm in size and can reach lengths up to 2.3 µm 1. Tupanvirus has the largest host range described so far among amoebal-infecting giant viruses and can causes a shutdown of host rRNA that is likely related to host-nucleolus degradation 1,3-9. The tupanviruses replication cycle is similar to those for other mim-iviruses, in which viral particles attach to the host-cell surface and enter through phagocytosis. The viral inner membrane then fuses with the phagosome membrane, releasing the genome. A viral factory (VF) is formed, where particle morphogenesis occurs; the cycle ends with cell lysis and the release of progeny viruses 1,10. The study of the tupanvirus genome further aroused the interest of virologists, not only due of its large size (~1.5 Mb), but also because these viruses show the largest translational apparatus described. It is composed of up to 70 tRNA, 20 aminoacyl-tRNA synthetases (aaRS), 11 factors associated with translation, and factors related to tRNA/mRNA maturation and Ribosome Protein modification 1. In addition to the robust translation apparatus, tupanvirus also contains a gene encoding mannose-specific lectin, also called mannose-binding Protein (MBP) 1. Interestingly, previous studies revealed that Acanthamoeba castellanii expresses an MBP and that free-mannose can inhibit the adhesion of A. castellanii to surfaces, suggesting that the MBP plays a role in the pathogenesis of Acanthamoeba infection 11-16 .
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tailed giant tupanvirus possesses the most complete translational apparatus of the known virosphere
Nature Communications, 2018Co-Authors: Jônatas Santos Abrahão, Ludmila Santos Silva, Thalita Souza Arantes, Lorena Silva, Jacques Yaacoub Bou Khalil, Rodrigo Araújo Lima Rodrigues, Felipe L. AssisAbstract:Here we report the discovery of two Tupanvirus strains, the longest tailed Mimiviridae members isolated in amoebae. Their genomes are 1.44–1.51 Mb linear double-strand DNA coding for 1276–1425 predicted Proteins. Tupanviruses share the same ancestors with mimivirus lineages and these giant viruses present the largest translational apparatus within the known virosphere, with up to 70 tRNA, 20 aaRS, 11 factors for all translation steps, and factors related to tRNA/mRNA maturation and Ribosome Protein modification. Moreover, two sequences with significant similarity to intronic regions of 18 S rRNA genes are encoded by the tupanviruses and highly expressed. In this translation-associated gene set, only the Ribosome is lacking. At high multiplicity of infections, tupanvirus is also cytotoxic and causes a severe shutdown of ribosomal RNA and a progressive degradation of the nucleus in host and non-host cells. The analysis of tupanviruses constitutes a new step toward understanding the evolution of giant viruses.
Jun Jiang - One of the best experts on this subject based on the ideXlab platform.
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the tight junction Protein transcript abundance changes and oxidative damage by tryptophan deficiency or excess are related to the modulation of the signalling molecules nf κb p65 tor caspase 3 8 9 and nrf2 mrna levels in the gill of young grass carp
Fish & Shellfish Immunology, 2015Co-Authors: Wuneng Tang, Juan Zhao, Weidan Jiang, Pei Wu, Jun Jiang, Shengyao Kuang, Ling Tang, Yongan ZhangAbstract:This study is for the first time to explore the possible effects of dietary tryptophan (Trp) on structural integrity and the related signalling factor gene expression in the gill of young grass carp (Ctenopharyngodon idella). Fish were fed with six different experimental diets containing graded levels of Trp at 0.7 (control), 1.7, 3.1, 4.0, 5.2 and 6.1 g kg(-1) diet for 8 weeks. The results firstly demonstrated that Trp deficiency or excess caused increases in reactive oxygen species (ROS) contents, and severe oxidative damage (lipid peroxidation and Protein oxidation) in the gill of fish, and those negative effects could be reversed by optimal Trp levels. Secondly, compared with the optimal Trp levels, Trp deficiency could cause decreases in the mRNA levels of the barrier functional Proteins (occludin, zonula occludens-1, claudin-c, and -3) and increases in the mRNA levels of the pore-formation Proteins (claudin-12 and -15) mRNA levels in the gill of fish, and those were reversed by the optimal levels of Trp. The negative effects of Trp deficiency on those tight junction Protein gene expression might be partly related to the increases in the mRNA levels of pro-inflammatory cytokines and related signalling factors (tumor necrosis factor a, interleukin 8, interleukin 10 and transcription factor-kappa B) and decreases in the mRNA levels of anti-inflammatory cytokines and related signalling factors [interleukin 10, transforming growth factor-beta 1, nuclear inhibitor factor kappa B alpha (i kappa B alpha), target of rapamyc and Ribosome Protein S6 kinase 1 (S6K1)] in the gill of fish. In addition, optimal dietary Trp protected the gill of fish against its deficiency-caused increases in the mRNA levels of the apoptosis signalling (caspase-3, caspase-8, caspase-9) and decreases in anti-superoxide radicals capacity, anti-hydroxyl radical capacity, glutathione contents and the activities of Cu/Zn superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione-S-transferase (GST) in the gill of fish. Additionally, compared with the Trp deficiency, optimal Trp up-regulated the mRNA levels of SOD, CAT, GPx, GR and GST, which might be partly ascribed to the up-regulation of the NF-E2-related factor 2 (Nrf2) mRNA levels and the down-regulation of Kelch-like-ECH-associated Protein 1 (Keap1) mRNA levels in the gill of fish. Interestingly, excessive Trp caused similar results with its deficiency. Collectively, Trp deficiency or excess could cause antioxidant system disruption and change tight junction Protein transcription abundances, which were partly related to the signalling factors, NF-kappa B p65, TOR, caspase-(3,8,9) and Nrf2, in fish gill, those could be blocked by the optimal Trp levels. (C) 2015 Elsevier Ltd. All rights reserved.
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effects of dietary arginine supplementation on growth performance flesh quality muscle antioxidant capacity and antioxidant related signalling molecule expression in young grass carp ctenopharyngodon idella
Food Chemistry, 2015Co-Authors: Biao Wang, Weidan Jiang, Jun Jiang, Shengyao Kuang, Yang Liu, Lin FengAbstract:Abstract Growth performance, flesh quality, antioxidant status and antioxidant-related signalling molecule expression in the muscle of young grass carp, which were fed graded levels of arginine (6.9–24.5 g/kg diet) for eight weeks, were investigated. Muscle Protein, lipid and nitric oxide contents, shear force, hydroxyproline concentration, and pH were significantly improved by appropriate arginine. Cooking loss, lactate content, cathepsins activities, malondialdehyde and Protein carbonyl contents exhibited an opposite tendency. Additionally, optimum arginine significantly enhanced glutathione content and the activities and gene expression of copper/zinc superoxide dismutase, catalase and glutathione peroxidase in muscle. Moreover, the expression levels of glutamate–cysteine ligase, target of rapamycin, Ribosome Protein S6 kinase 1, casein kinase 2 and NF-E2-related factor 2 in muscle were significantly elevated by appropriate arginine. However, optimum arginine significantly decreased Kelch-like ECH-associated Protein 1 mRNA levels in muscle. In conclusion, arginine improved the flesh quality and muscle antioxidant capacity and regulated antioxidant-related signalling molecule expression.
Felipe L. Assis - One of the best experts on this subject based on the ideXlab platform.
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tailed giant tupanvirus possesses the most complete translational apparatus of the known virosphere
Nature Communications, 2018Co-Authors: Jônatas Santos Abrahão, Ludmila Santos Silva, Thalita Souza Arantes, Lorena Silva, Jacques Yaacoub Bou Khalil, Rodrigo Araújo Lima Rodrigues, Felipe L. AssisAbstract:Here we report the discovery of two Tupanvirus strains, the longest tailed Mimiviridae members isolated in amoebae. Their genomes are 1.44–1.51 Mb linear double-strand DNA coding for 1276–1425 predicted Proteins. Tupanviruses share the same ancestors with mimivirus lineages and these giant viruses present the largest translational apparatus within the known virosphere, with up to 70 tRNA, 20 aaRS, 11 factors for all translation steps, and factors related to tRNA/mRNA maturation and Ribosome Protein modification. Moreover, two sequences with significant similarity to intronic regions of 18 S rRNA genes are encoded by the tupanviruses and highly expressed. In this translation-associated gene set, only the Ribosome is lacking. At high multiplicity of infections, tupanvirus is also cytotoxic and causes a severe shutdown of ribosomal RNA and a progressive degradation of the nucleus in host and non-host cells. The analysis of tupanviruses constitutes a new step toward understanding the evolution of giant viruses.
Weidan Jiang - One of the best experts on this subject based on the ideXlab platform.
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the tight junction Protein transcript abundance changes and oxidative damage by tryptophan deficiency or excess are related to the modulation of the signalling molecules nf κb p65 tor caspase 3 8 9 and nrf2 mrna levels in the gill of young grass carp
Fish & Shellfish Immunology, 2015Co-Authors: Wuneng Tang, Juan Zhao, Weidan Jiang, Pei Wu, Jun Jiang, Shengyao Kuang, Ling Tang, Yongan ZhangAbstract:This study is for the first time to explore the possible effects of dietary tryptophan (Trp) on structural integrity and the related signalling factor gene expression in the gill of young grass carp (Ctenopharyngodon idella). Fish were fed with six different experimental diets containing graded levels of Trp at 0.7 (control), 1.7, 3.1, 4.0, 5.2 and 6.1 g kg(-1) diet for 8 weeks. The results firstly demonstrated that Trp deficiency or excess caused increases in reactive oxygen species (ROS) contents, and severe oxidative damage (lipid peroxidation and Protein oxidation) in the gill of fish, and those negative effects could be reversed by optimal Trp levels. Secondly, compared with the optimal Trp levels, Trp deficiency could cause decreases in the mRNA levels of the barrier functional Proteins (occludin, zonula occludens-1, claudin-c, and -3) and increases in the mRNA levels of the pore-formation Proteins (claudin-12 and -15) mRNA levels in the gill of fish, and those were reversed by the optimal levels of Trp. The negative effects of Trp deficiency on those tight junction Protein gene expression might be partly related to the increases in the mRNA levels of pro-inflammatory cytokines and related signalling factors (tumor necrosis factor a, interleukin 8, interleukin 10 and transcription factor-kappa B) and decreases in the mRNA levels of anti-inflammatory cytokines and related signalling factors [interleukin 10, transforming growth factor-beta 1, nuclear inhibitor factor kappa B alpha (i kappa B alpha), target of rapamyc and Ribosome Protein S6 kinase 1 (S6K1)] in the gill of fish. In addition, optimal dietary Trp protected the gill of fish against its deficiency-caused increases in the mRNA levels of the apoptosis signalling (caspase-3, caspase-8, caspase-9) and decreases in anti-superoxide radicals capacity, anti-hydroxyl radical capacity, glutathione contents and the activities of Cu/Zn superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione-S-transferase (GST) in the gill of fish. Additionally, compared with the Trp deficiency, optimal Trp up-regulated the mRNA levels of SOD, CAT, GPx, GR and GST, which might be partly ascribed to the up-regulation of the NF-E2-related factor 2 (Nrf2) mRNA levels and the down-regulation of Kelch-like-ECH-associated Protein 1 (Keap1) mRNA levels in the gill of fish. Interestingly, excessive Trp caused similar results with its deficiency. Collectively, Trp deficiency or excess could cause antioxidant system disruption and change tight junction Protein transcription abundances, which were partly related to the signalling factors, NF-kappa B p65, TOR, caspase-(3,8,9) and Nrf2, in fish gill, those could be blocked by the optimal Trp levels. (C) 2015 Elsevier Ltd. All rights reserved.
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effects of dietary arginine supplementation on growth performance flesh quality muscle antioxidant capacity and antioxidant related signalling molecule expression in young grass carp ctenopharyngodon idella
Food Chemistry, 2015Co-Authors: Biao Wang, Weidan Jiang, Jun Jiang, Shengyao Kuang, Yang Liu, Lin FengAbstract:Abstract Growth performance, flesh quality, antioxidant status and antioxidant-related signalling molecule expression in the muscle of young grass carp, which were fed graded levels of arginine (6.9–24.5 g/kg diet) for eight weeks, were investigated. Muscle Protein, lipid and nitric oxide contents, shear force, hydroxyproline concentration, and pH were significantly improved by appropriate arginine. Cooking loss, lactate content, cathepsins activities, malondialdehyde and Protein carbonyl contents exhibited an opposite tendency. Additionally, optimum arginine significantly enhanced glutathione content and the activities and gene expression of copper/zinc superoxide dismutase, catalase and glutathione peroxidase in muscle. Moreover, the expression levels of glutamate–cysteine ligase, target of rapamycin, Ribosome Protein S6 kinase 1, casein kinase 2 and NF-E2-related factor 2 in muscle were significantly elevated by appropriate arginine. However, optimum arginine significantly decreased Kelch-like ECH-associated Protein 1 mRNA levels in muscle. In conclusion, arginine improved the flesh quality and muscle antioxidant capacity and regulated antioxidant-related signalling molecule expression.
Lorena Silva - One of the best experts on this subject based on the ideXlab platform.
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Tupanvirus-infected amoebas are induced to aggregate with uninfected cells promoting viral dissemination
Scientific Reports, 2019Co-Authors: Graziele Oliveira, Lorena Silva, Thiago Leão, Said Mougari, Flávio Guimarães Da Fonseca, Erna Geessien Kroon, Bernard La Scola, Jônatas Santos AbrahãoAbstract:The discovery of giant viruses in the last years has fascinated the scientific community due to virus particles size and genome complexity. Among such fantastic discoveries, we have recently described tupanviruses, which particles present a long tail, and has a genome that contains the most complete set of translation-related genes ever reported in the known virosphere. Here we describe a new kind of virus-host interaction involving tupanvirus. We observed that tupanvirus-infected amoebas were induced to aggregate with uninfected cells, promoting viral dissemination and forming giant host cell bunches. Even after mechanical breakdown of bunches, amoebas reaggregated within a few minutes. This remarkable interaction between infected and uninfected cells seems to be promoted by the expression of a mannose receptor gene. Our investigations demonstrate that the pre-treatment of amoebas with free mannose inhibits the formation of bunches, in a concentration-dependent manner, suggesting that amoebal-bunch formation correlates with mannose receptor gene expression. Finally, our data suggest that bunch-forming cells are able to interact with uninfected cells promoting the dissemination and increase of tupanvirus progeny. The recent discovery of tupanvirus, one of the largest and most complex viruses isolated to date, has reinforced the structural and genomic complexity of the giant viruses 1. Tupanviruses have been isolated from soda lakes, known as an extreme aquatic environments, and from ocean sediments collected at a depth of 3000 meters (m) 1,2. Phylogenetic analyses have shown the clustering of the tupanvirus with members of the family Mimiviridae. However, there are many peculiarities that make the tupanviruses unique entities in the known virosphere. Since its first observation, tupanviruses showed remarkable morphological characteristics; it has optically visible particles that average about 1.2 µm in size and can reach lengths up to 2.3 µm 1. Tupanvirus has the largest host range described so far among amoebal-infecting giant viruses and can causes a shutdown of host rRNA that is likely related to host-nucleolus degradation 1,3-9. The tupanviruses replication cycle is similar to those for other mim-iviruses, in which viral particles attach to the host-cell surface and enter through phagocytosis. The viral inner membrane then fuses with the phagosome membrane, releasing the genome. A viral factory (VF) is formed, where particle morphogenesis occurs; the cycle ends with cell lysis and the release of progeny viruses 1,10. The study of the tupanvirus genome further aroused the interest of virologists, not only due of its large size (~1.5 Mb), but also because these viruses show the largest translational apparatus described. It is composed of up to 70 tRNA, 20 aminoacyl-tRNA synthetases (aaRS), 11 factors associated with translation, and factors related to tRNA/mRNA maturation and Ribosome Protein modification 1. In addition to the robust translation apparatus, tupanvirus also contains a gene encoding mannose-specific lectin, also called mannose-binding Protein (MBP) 1. Interestingly, previous studies revealed that Acanthamoeba castellanii expresses an MBP and that free-mannose can inhibit the adhesion of A. castellanii to surfaces, suggesting that the MBP plays a role in the pathogenesis of Acanthamoeba infection 11-16 .
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tailed giant tupanvirus possesses the most complete translational apparatus of the known virosphere
Nature Communications, 2018Co-Authors: Jônatas Santos Abrahão, Ludmila Santos Silva, Thalita Souza Arantes, Lorena Silva, Jacques Yaacoub Bou Khalil, Rodrigo Araújo Lima Rodrigues, Felipe L. AssisAbstract:Here we report the discovery of two Tupanvirus strains, the longest tailed Mimiviridae members isolated in amoebae. Their genomes are 1.44–1.51 Mb linear double-strand DNA coding for 1276–1425 predicted Proteins. Tupanviruses share the same ancestors with mimivirus lineages and these giant viruses present the largest translational apparatus within the known virosphere, with up to 70 tRNA, 20 aaRS, 11 factors for all translation steps, and factors related to tRNA/mRNA maturation and Ribosome Protein modification. Moreover, two sequences with significant similarity to intronic regions of 18 S rRNA genes are encoded by the tupanviruses and highly expressed. In this translation-associated gene set, only the Ribosome is lacking. At high multiplicity of infections, tupanvirus is also cytotoxic and causes a severe shutdown of ribosomal RNA and a progressive degradation of the nucleus in host and non-host cells. The analysis of tupanviruses constitutes a new step toward understanding the evolution of giant viruses.
