The Experts below are selected from a list of 9027 Experts worldwide ranked by ideXlab platform
Laurent Kremer - One of the best experts on this subject based on the ideXlab platform.
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CFTR Depletion Confers Hypersusceptibility to Mycobacterium fortuitum in a Zebrafish Model
Frontiers in Cellular and Infection Microbiology, 2020Co-Authors: Matt Johansen, Laurent KremerAbstract:The Mycobacterium fortuitum complex comprises several closely related species, causing pulmonary and extra-pulmonary infections. However, there is very limited knowledge about the disease pathogenesis involved in M. fortuitum infections, particularly due to the lack of suitable animal models. Using the zebrafish model, we show that Embryos are susceptible to M. fortuitum infection in a dose-dependent manner. Furthermore, zebrafish Embryos form granulomas from as early as 2 days post-infection, recapitulating critical aspects of mycobacterial pathogenesis observed in other pathogenic species. The formation of extracellular cords in infected Embryos highlights a previously unknown pathogenic feature of M. fortuitum. The formation of large corded structures occurs also during in vitro growth, suggesting that this is not a host-adapted stress mechanism deployed during infection. Moreover, transient macrophage depletion led to rapid Embryo Death with increased extracellular cords, indicating that macrophages are essential determinants of M. fortuitum infection control. Importantly, morpholino depletion of the cystic fibrosis transmembrane conductance regulator (cftr) significantly increased Embryo Death, bacterial burden, bacterial cords and abscesses. There was a noticeable decrease in the number of cftr-deficient infected Embryos with granulomas as compared to infected controls, suggesting that loss of CFTR leads to impaired host immune responses and confers hypersusceptiblity to M. fortuitum infection. Overall, these findings highlight the application of the zebrafish Embryo to study M. fortuitum and emphasizes previously unexplored aspects of disease pathogenesis of this significant mycobacterial species.
Colin J Limpus - One of the best experts on this subject based on the ideXlab platform.
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the effect of respiratory gases and incubation temperature on early stage Embryonic development in sea turtles
PLOS ONE, 2020Co-Authors: David T Booth, Alexander Archibaldbinge, Colin J LimpusAbstract:Sea turtle Embryos at high-density nesting beaches experience relative high rates of early stage Embryo Death. One hypothesis to explain this high mortality rate is that there is an increased probability that newly constructed nests are located close to maturing clutches whose metabolising Embryos cause low oxygen levels, high carbon dioxide levels, and high temperatures. Although these altered environmental conditions are well tolerated by mature Embryos, early stage Embryos, i.e. Embryos in eggs that have only been incubating for less than a week, may not be as tolerant leading to an increase in their mortality. To test this hypothesis, we incubated newly laid sea turtle eggs over a range of temperatures in different combinations of oxygen and carbon dioxide concentrations and assessed Embryo development and Death rates. We found that gas mixtures of decreased oxygen and increased carbon dioxide, similar to those found in natural sea turtle nests containing mature Embryos, slowed Embryonic development but did not influence the mortality rate of early stage Embryos. We found incubation temperature had no effect on early Embryo mortality but growth rate at 27°C and 34°C was slower than at 30°C and 33°C. Our findings indicate that low oxygen and high carbon dioxide partial pressures are not the cause of the high early stage Embryo mortality observed at high-density sea turtle nesting beaches, but there is evidence suggesting high incubation temperatures, particularly above 34°C are harmful. Any management strategies that can increase the spacing between nests or other strategies such as shading or irrigation that reduce sand temperature are likely to increase hatching success at high-density nesting beaches.
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the effect of respiratory gases and incubation temperature on early stage Embryonic development in sea turtles
bioRxiv, 2020Co-Authors: David T Booth, Alexander Archibaldbinge, Colin J LimpusAbstract:Abstract Sea turtle Embryos at high density nesting beaches experience relative high rates of early stage Embryo Death. One hypothesis to explain this high dead rate is that there is an increased probability that newly constructed nests are located close to maturing clutches whose metabolising Embryos cause low oxygen levels, high carbon dioxide levels, and high temperatures. Although these altered environmental conditions are well tolerated by mature Embryos, early stage Embryos may not be as tolerant leading to an increase in their mortality. To test this hypothesis, we incubated newly laid sea turtle eggs for a week over a range of temperatures in different combinations of oxygen and carbon dioxide concentrations and assessed Embryo development and Death rates. We found that gas mixtures of decreased oxygen and increased carbon dioxide, similar to those found in natural sea turtle nest containing mature Embryos, slowed Embryonic development but did not influence Embryo mortality of early stage Embryos. In contrast, high incubation temperature not only decreased Embryo development rate, but prolonged incubation at 34°C was fatal.
Hazem Ramadan - One of the best experts on this subject based on the ideXlab platform.
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Table_1_Genomic Investigation of Antimicrobial-Resistant Salmonella enterica Isolates From Dead Chick Embryos in China.XLSX
'Frontiers Media SA', 2021Co-Authors: Mohammed Elbediwi, Yanting Tang, Dawei Shi, Hazem Ramadan, Min YueAbstract:Salmonella spp. is recognized as an important zoonotic pathogen. The emergence of antimicrobial resistance in Salmonella enterica poses a great public health concern worldwide. While the knowledge on the incidence and the characterization of different S. enterica serovars causing chick Embryo Death remains obscure in China. In this study, we obtained 45 S. enterica isolates from 2,139 dead chick Embryo samples collected from 28 breeding chicken hatcheries in Henan province. The antimicrobial susceptibility assay was performed by the broth microdilution method and the results showed that 31/45 (68.8%) isolates were multidrug-resistant (≥3 antimicrobial classes). Besides the highest resistance rate was observed in the aminoglycoside class, all the isolates were susceptible to chloramphenicol, azithromycin, and imipenem. Furthermore, genomic characterization revealed that S. Enteritidis (33.33%; 15/45) was a frequent serovar that harbored a higher number of virulence factors compared to other serovars. Importantly, genes encoding β-lactamases were identified in three serovars (Thompson, Enteritidis, and Kottbus), whereas plasmid-mediated quinolone resistance genes (qnrB4) were detected in certain isolates of S. Thompson and the two S. Kottbus isolates. All the examined isolates harbored the typical virulence factors from Salmonella pathogenicity islands 1 and 2 (SPI-1 and SPI-2). Additionally, a correlation analysis between the antimicrobial resistance genes, phenotype, and plasmids was conducted among Salmonella isolates. It showed strong positive correlations (r −0.6) with IncHI2 and IncHI2A plasmids. Together, our study demonstrated antimicrobial-resistant S. enterica circulating in breeding chicken hatcheries in Henan province, highlighting the advanced approach, by using genomic characterization and statistical analysis, in conducting the routine monitoring of the emerging antimicrobial-resistant pathogens. Our findings also proposed that the day-old breeder chicks trading could be one of the potential pathways for the dissemination of multidrug-resistant S. enterica serovars.
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Genomic Investigation of Antimicrobial-Resistant Salmonella enterica Isolates From Dead Chick Embryos in China
'Frontiers Media SA', 2021Co-Authors: Mohammed Elbediwi, Yanting Tang, Dawei Shi, Hazem RamadanAbstract:Salmonella spp. is recognized as an important zoonotic pathogen. The emergence of antimicrobial resistance in Salmonella enterica poses a great public health concern worldwide. While the knowledge on the incidence and the characterization of different S. enterica serovars causing chick Embryo Death remains obscure in China. In this study, we obtained 45 S. enterica isolates from 2,139 dead chick Embryo samples collected from 28 breeding chicken hatcheries in Henan province. The antimicrobial susceptibility assay was performed by the broth microdilution method and the results showed that 31/45 (68.8%) isolates were multidrug-resistant (≥3 antimicrobial classes). Besides the highest resistance rate was observed in the aminoglycoside class, all the isolates were susceptible to chloramphenicol, azithromycin, and imipenem. Furthermore, genomic characterization revealed that S. Enteritidis (33.33%; 15/45) was a frequent serovar that harbored a higher number of virulence factors compared to other serovars. Importantly, genes encoding β-lactamases were identified in three serovars (Thompson, Enteritidis, and Kottbus), whereas plasmid-mediated quinolone resistance genes (qnrB4) were detected in certain isolates of S. Thompson and the two S. Kottbus isolates. All the examined isolates harbored the typical virulence factors from Salmonella pathogenicity islands 1 and 2 (SPI-1 and SPI-2). Additionally, a correlation analysis between the antimicrobial resistance genes, phenotype, and plasmids was conducted among Salmonella isolates. It showed strong positive correlations (r < 0.6) between the different antimicrobial-resistant genes belonging to certain antimicrobial classes. Besides, IncF plasmid showed a strong negative correlation (r > −0.6) with IncHI2 and IncHI2A plasmids. Together, our study demonstrated antimicrobial-resistant S. enterica circulating in breeding chicken hatcheries in Henan province, highlighting the advanced approach, by using genomic characterization and statistical analysis, in conducting the routine monitoring of the emerging antimicrobial-resistant pathogens. Our findings also proposed that the day-old breeder chicks trading could be one of the potential pathways for the dissemination of multidrug-resistant S. enterica serovars
Matt Johansen - One of the best experts on this subject based on the ideXlab platform.
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CFTR Depletion Confers Hypersusceptibility to Mycobacterium fortuitum in a Zebrafish Model
Frontiers in Cellular and Infection Microbiology, 2020Co-Authors: Matt Johansen, Laurent KremerAbstract:The Mycobacterium fortuitum complex comprises several closely related species, causing pulmonary and extra-pulmonary infections. However, there is very limited knowledge about the disease pathogenesis involved in M. fortuitum infections, particularly due to the lack of suitable animal models. Using the zebrafish model, we show that Embryos are susceptible to M. fortuitum infection in a dose-dependent manner. Furthermore, zebrafish Embryos form granulomas from as early as 2 days post-infection, recapitulating critical aspects of mycobacterial pathogenesis observed in other pathogenic species. The formation of extracellular cords in infected Embryos highlights a previously unknown pathogenic feature of M. fortuitum. The formation of large corded structures occurs also during in vitro growth, suggesting that this is not a host-adapted stress mechanism deployed during infection. Moreover, transient macrophage depletion led to rapid Embryo Death with increased extracellular cords, indicating that macrophages are essential determinants of M. fortuitum infection control. Importantly, morpholino depletion of the cystic fibrosis transmembrane conductance regulator (cftr) significantly increased Embryo Death, bacterial burden, bacterial cords and abscesses. There was a noticeable decrease in the number of cftr-deficient infected Embryos with granulomas as compared to infected controls, suggesting that loss of CFTR leads to impaired host immune responses and confers hypersusceptiblity to M. fortuitum infection. Overall, these findings highlight the application of the zebrafish Embryo to study M. fortuitum and emphasizes previously unexplored aspects of disease pathogenesis of this significant mycobacterial species.
David T Booth - One of the best experts on this subject based on the ideXlab platform.
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the effect of respiratory gases and incubation temperature on early stage Embryonic development in sea turtles
PLOS ONE, 2020Co-Authors: David T Booth, Alexander Archibaldbinge, Colin J LimpusAbstract:Sea turtle Embryos at high-density nesting beaches experience relative high rates of early stage Embryo Death. One hypothesis to explain this high mortality rate is that there is an increased probability that newly constructed nests are located close to maturing clutches whose metabolising Embryos cause low oxygen levels, high carbon dioxide levels, and high temperatures. Although these altered environmental conditions are well tolerated by mature Embryos, early stage Embryos, i.e. Embryos in eggs that have only been incubating for less than a week, may not be as tolerant leading to an increase in their mortality. To test this hypothesis, we incubated newly laid sea turtle eggs over a range of temperatures in different combinations of oxygen and carbon dioxide concentrations and assessed Embryo development and Death rates. We found that gas mixtures of decreased oxygen and increased carbon dioxide, similar to those found in natural sea turtle nests containing mature Embryos, slowed Embryonic development but did not influence the mortality rate of early stage Embryos. We found incubation temperature had no effect on early Embryo mortality but growth rate at 27°C and 34°C was slower than at 30°C and 33°C. Our findings indicate that low oxygen and high carbon dioxide partial pressures are not the cause of the high early stage Embryo mortality observed at high-density sea turtle nesting beaches, but there is evidence suggesting high incubation temperatures, particularly above 34°C are harmful. Any management strategies that can increase the spacing between nests or other strategies such as shading or irrigation that reduce sand temperature are likely to increase hatching success at high-density nesting beaches.
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the effect of respiratory gases and incubation temperature on early stage Embryonic development in sea turtles
bioRxiv, 2020Co-Authors: David T Booth, Alexander Archibaldbinge, Colin J LimpusAbstract:Abstract Sea turtle Embryos at high density nesting beaches experience relative high rates of early stage Embryo Death. One hypothesis to explain this high dead rate is that there is an increased probability that newly constructed nests are located close to maturing clutches whose metabolising Embryos cause low oxygen levels, high carbon dioxide levels, and high temperatures. Although these altered environmental conditions are well tolerated by mature Embryos, early stage Embryos may not be as tolerant leading to an increase in their mortality. To test this hypothesis, we incubated newly laid sea turtle eggs for a week over a range of temperatures in different combinations of oxygen and carbon dioxide concentrations and assessed Embryo development and Death rates. We found that gas mixtures of decreased oxygen and increased carbon dioxide, similar to those found in natural sea turtle nest containing mature Embryos, slowed Embryonic development but did not influence Embryo mortality of early stage Embryos. In contrast, high incubation temperature not only decreased Embryo development rate, but prolonged incubation at 34°C was fatal.