The Experts below are selected from a list of 5352 Experts worldwide ranked by ideXlab platform
Javier R. Ambrosio - One of the best experts on this subject based on the ideXlab platform.
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androgens exert a cysticidal effect upon taenia crassiceps by disrupting Flame Cell morphology and function
PLOS ONE, 2015Co-Authors: Javier R. Ambrosio, Olivia Reynosoducoing, Karen Elizabeth Navacastro, Pedro Ostoasaloma, Galileo Escobedo, Azucena Ruizrosado, Laura Valverdeislas, Isabel Palacios M Arreola, Lenin DominguezramirezAbstract:The effects of testosterone (T4) and dihydrotestosterone (DHT) on the survival of the helminth cestode parasite Taenia crassiceps, as well as their effects on actin, tubulin and myosin expression and their assembly into the excretory system of Flame Cells are described in this paper. In vitro evaluations on parasite viability, flow cytometry, confocal microscopy, video-microscopy of live Flame Cells, and docking experiments of androgens interacting with actin, tubulin, and myosin were conducted. Our results show that T4 and DHT reduce T. crassiceps viability in a dose- and time-dependent fashion, reaching 90% of mortality at the highest dose used (40 ng/ml) and time exposed (10 days) in culture. Androgen treatment does not induce differences in the specific expression pattern of actin, tubulin, and myosin isoforms as compared with control parasites. Confocal microscopy demonstrated a strong disruption of the parasite tegument, with reduced assembly, shape, and motion of Flame Cells. Docking experiments show that androgens are capable of affecting parasite survival and Flame Cell morphology by directly interacting with actin, tubulin and myosin without altering their protein expression pattern. We show that both T4 and DHT are able to bind actin, tubulin, and myosin affecting their assembly and causing parasite intoxication due to impairment of Flame Cell function. Live Flame Cell video microscopy showing a reduced motion as well changes in the shape of Flame Cells are also shown. In summary, T4 and DHT directly act on T. crassiceps cysticerci through altering parasite survival as well as the assembly and function of Flame Cells.
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oestradiol and progesterone differentially alter cytoskeletal protein expression and Flame Cell morphology in taenia crassiceps
International Journal for Parasitology, 2014Co-Authors: Javier R. Ambrosio, Olivia Reynosoducoing, Karen Elizabeth Navacastro, Pedro Ostoasaloma, Galileo Escobedo, Isabel M Palaciosarreola, Azucena Ruizrosado, Pedro L Sanchezorellana, Nancy Martinezvelazquez, Elizabeth IbarracoronadoAbstract:We examined the effects of oestradiol (E2) and progesterone (P4) on cytoskeletal protein expression in the helminth Taenia crassiceps — specifically actin, tubulin and myosin. These proteins assemble into Flame Cells, which constitute the parasite excretory system. Total protein extracts were obtained from E2- and P4-treated T. crassiceps cysticerci and untreated controls, and analysed by one- and two-dimensional protein electrophoresis, flow cytometry, immunofluorescence and videomicroscopy. Exposure of T. crassiceps cysticerci to E2 and P4 induced differential protein expression patterns compared with untreated controls. Changes in actin, tubulin and myosin expression were confirmed by flow cytometry of parasite Cells and immunofluorescence. In addition, parasite morphology was altered in response to E2 and P4 versus controls. Flame Cells were primarily affected at the level of the ciliary tuft, in association with the changes in actin, tubulin and myosin. We conclude that oestradiol and progesterone act directly on T. crassiceps cysticerci, altering actin, tubulin and myosin expression and thus affecting the assembly and function of Flame Cells. Our results increase our understanding of several aspects of the molecular crosstalk between host and parasite, which might be useful in designing anthelmintic drugs that exclusively impair parasitic proteins which mediate Cell signaling and pathogenic reproduction and establishment.
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visualization and 3d reconstruction of Flame Cells of taenia solium cestoda
PLOS ONE, 2011Co-Authors: Laura Valverdeislas, Olivia Reynosoducoing, Esteban Arrangoiz, Elio Vega, Lilia Robert, Rafael Villanueva, Kaethe Willms, Armando Zepedarodriguez, Teresa I Fortoul, Javier R. AmbrosioAbstract:Background Flame Cells are the terminal Cells of protonephridial systems, which are part of the excretory systems of invertebrates. Although the knowledge of their biological role is incomplete, there is a consensus that these Cells perform excretion/secretion activities. It has been suggested that the Flame Cells participate in the maintenance of the osmotic environment that the cestodes require to live inside their hosts. In live Platyhelminthes, by light microscopy, the Cells appear beating their Flames rapidly and, at the ultrastructural, the Cells have a large body enclosing a tuft of cilia. Few studies have been performed to define the localization of the cytoskeletal proteins of these Cells, and it is unclear how these proteins are involved in Cell function. Methodology/Principal Findings Parasites of two different developmental stages of T. solium were used: cysticerci recovered from naturally infected pigs and intestinal adults obtained from immunosuppressed and experimentally infected golden hamsters. Hamsters were fed viable cysticerci to recover adult parasites after one month of infection. In the present studies focusing on Flame Cells of cysticerci tissues was performed. Using several methods such as video, confocal and electron microscopy, in addition to computational analysis for reconstruction and modeling, we have provided a 3D visual rendition of the cytoskeletal architecture of Taenia solium Flame Cells. Conclusions/Significance We consider that visual representations of Cells open a new way for understanding the role of these Cells in the excretory systems of Platyhelminths. After reconstruction, the observation of high resolution 3D images allowed for virtual observation of the interior composition of Cells. A combination of microscopic images, computational reconstructions and 3D modeling of Cells appears to be useful for inferring the Cellular dynamics of the Flame Cell cytoskeleton.
Chung King Law - One of the best experts on this subject based on the ideXlab platform.
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On Flame-front instability at elevated pressures
Proceedings of the Combustion Institute, 2007Co-Authors: Jiao Yuan, Chung King LawAbstract:Abstract Effects of pressure up to 3 atm on Flame-front instability were numerically investigated for both linear and nonlinear growth stages at sub-unity and unity Lewis numbers. A sixth-order compact scheme and non-reflecting boundary conditions were used to capture the evolution of the Flame front. Results show that in the linear instability growth stage, elevated pressure can extend the unstable range of Flame-fronts and generate the fine Flame Cell structure. This effect can be qualitatively predicted by the theories when Le = 1.0; however the theories diverge at sub-unity Lewis numbers (e.g. Le = 0.7). In the nonlinear growth stage, the critical wave number (kc) from the linear dispersion relation can be used as a reference length scale for the evolution of the Flame Cell structure. Since elevated pressure increases the critical wave number, small Flame Cells appear over large Flame Cells (deep folds) at high ambient pressures. Furthermore, Flame-front hydrodynamic instability is excited when the lateral domain is enlarged.
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Pulsating and hydrodynamic instabilities at large Lewis numbers
Combustion and Flame, 2005Co-Authors: Jiao Yuan, Chung King LawAbstract:The dynamic behavior of freely propagating premixed Flames with large Lewis numbers was computationally simulated using a sixth-order central difference scheme and nonreflective boundary conditions. Results in the linear stage of the instability growth show that the growth rate dramatically decreases with increasing Lewis number and that the large activation energy excites the pulsating instability and increases the growth rate of the hydrodynamic instability. In the nonlinear growth stage, there exist regimes of stable Cell propagation, periodic pulsating Cellular Flames, and irregular pulsating Cellular Flames as the activation energy is increased. Characteristics of these regimes were further studied for the effects of Lewis number on the Flame front structure in the regime of stable Cell propagation, the effects of Flame pulsation on the flow and Flame Cell structure in the regime of periodic pulsating Cellular Flame, and the complex pattern formation in the regime of irregular pulsating Cellular Flame. It is further demonstrated that unsteady pulsating Flames can propagate faster than the adiabatic Flame when the local stretch rate is positive, implying that models based on quasi-steady Flame propagation may not correctly predict the behavior of unsteady Flames with large Lewis numbers.
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coupled hydrodynamic and diffusional thermal instabilities in Flame propagation at subunity lewis numbers
Physics of Fluids, 2005Co-Authors: Jiao Yuan, Chung King LawAbstract:The dynamics of Flame Cell evolution due to the coupling between hydrodynamic and diffusional-thermal instabilities in subunity Lewis number Flames was simulated using a sixth-order central difference scheme and newly developed nonreflective boundary conditions. Results show that the interaction between these two modes of instabilities yields distinct evolutions of Cell splitting, merging, growth, local extinction, and lateral motion, leading to fluctuations of the flow and species concentrations as well as substantial increase in the Flame speed. The study also demonstrates that small computational domains cannot correctly predict Cell merging and transverse motion.
Olivia Reynosoducoing - One of the best experts on this subject based on the ideXlab platform.
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androgens exert a cysticidal effect upon taenia crassiceps by disrupting Flame Cell morphology and function
PLOS ONE, 2015Co-Authors: Javier R. Ambrosio, Olivia Reynosoducoing, Karen Elizabeth Navacastro, Pedro Ostoasaloma, Galileo Escobedo, Azucena Ruizrosado, Laura Valverdeislas, Isabel Palacios M Arreola, Lenin DominguezramirezAbstract:The effects of testosterone (T4) and dihydrotestosterone (DHT) on the survival of the helminth cestode parasite Taenia crassiceps, as well as their effects on actin, tubulin and myosin expression and their assembly into the excretory system of Flame Cells are described in this paper. In vitro evaluations on parasite viability, flow cytometry, confocal microscopy, video-microscopy of live Flame Cells, and docking experiments of androgens interacting with actin, tubulin, and myosin were conducted. Our results show that T4 and DHT reduce T. crassiceps viability in a dose- and time-dependent fashion, reaching 90% of mortality at the highest dose used (40 ng/ml) and time exposed (10 days) in culture. Androgen treatment does not induce differences in the specific expression pattern of actin, tubulin, and myosin isoforms as compared with control parasites. Confocal microscopy demonstrated a strong disruption of the parasite tegument, with reduced assembly, shape, and motion of Flame Cells. Docking experiments show that androgens are capable of affecting parasite survival and Flame Cell morphology by directly interacting with actin, tubulin and myosin without altering their protein expression pattern. We show that both T4 and DHT are able to bind actin, tubulin, and myosin affecting their assembly and causing parasite intoxication due to impairment of Flame Cell function. Live Flame Cell video microscopy showing a reduced motion as well changes in the shape of Flame Cells are also shown. In summary, T4 and DHT directly act on T. crassiceps cysticerci through altering parasite survival as well as the assembly and function of Flame Cells.
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oestradiol and progesterone differentially alter cytoskeletal protein expression and Flame Cell morphology in taenia crassiceps
International Journal for Parasitology, 2014Co-Authors: Javier R. Ambrosio, Olivia Reynosoducoing, Karen Elizabeth Navacastro, Pedro Ostoasaloma, Galileo Escobedo, Isabel M Palaciosarreola, Azucena Ruizrosado, Pedro L Sanchezorellana, Nancy Martinezvelazquez, Elizabeth IbarracoronadoAbstract:We examined the effects of oestradiol (E2) and progesterone (P4) on cytoskeletal protein expression in the helminth Taenia crassiceps — specifically actin, tubulin and myosin. These proteins assemble into Flame Cells, which constitute the parasite excretory system. Total protein extracts were obtained from E2- and P4-treated T. crassiceps cysticerci and untreated controls, and analysed by one- and two-dimensional protein electrophoresis, flow cytometry, immunofluorescence and videomicroscopy. Exposure of T. crassiceps cysticerci to E2 and P4 induced differential protein expression patterns compared with untreated controls. Changes in actin, tubulin and myosin expression were confirmed by flow cytometry of parasite Cells and immunofluorescence. In addition, parasite morphology was altered in response to E2 and P4 versus controls. Flame Cells were primarily affected at the level of the ciliary tuft, in association with the changes in actin, tubulin and myosin. We conclude that oestradiol and progesterone act directly on T. crassiceps cysticerci, altering actin, tubulin and myosin expression and thus affecting the assembly and function of Flame Cells. Our results increase our understanding of several aspects of the molecular crosstalk between host and parasite, which might be useful in designing anthelmintic drugs that exclusively impair parasitic proteins which mediate Cell signaling and pathogenic reproduction and establishment.
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visualization and 3d reconstruction of Flame Cells of taenia solium cestoda
PLOS ONE, 2011Co-Authors: Laura Valverdeislas, Olivia Reynosoducoing, Esteban Arrangoiz, Elio Vega, Lilia Robert, Rafael Villanueva, Kaethe Willms, Armando Zepedarodriguez, Teresa I Fortoul, Javier R. AmbrosioAbstract:Background Flame Cells are the terminal Cells of protonephridial systems, which are part of the excretory systems of invertebrates. Although the knowledge of their biological role is incomplete, there is a consensus that these Cells perform excretion/secretion activities. It has been suggested that the Flame Cells participate in the maintenance of the osmotic environment that the cestodes require to live inside their hosts. In live Platyhelminthes, by light microscopy, the Cells appear beating their Flames rapidly and, at the ultrastructural, the Cells have a large body enclosing a tuft of cilia. Few studies have been performed to define the localization of the cytoskeletal proteins of these Cells, and it is unclear how these proteins are involved in Cell function. Methodology/Principal Findings Parasites of two different developmental stages of T. solium were used: cysticerci recovered from naturally infected pigs and intestinal adults obtained from immunosuppressed and experimentally infected golden hamsters. Hamsters were fed viable cysticerci to recover adult parasites after one month of infection. In the present studies focusing on Flame Cells of cysticerci tissues was performed. Using several methods such as video, confocal and electron microscopy, in addition to computational analysis for reconstruction and modeling, we have provided a 3D visual rendition of the cytoskeletal architecture of Taenia solium Flame Cells. Conclusions/Significance We consider that visual representations of Cells open a new way for understanding the role of these Cells in the excretory systems of Platyhelminths. After reconstruction, the observation of high resolution 3D images allowed for virtual observation of the interior composition of Cells. A combination of microscopic images, computational reconstructions and 3D modeling of Cells appears to be useful for inferring the Cellular dynamics of the Flame Cell cytoskeleton.
Jiao Yuan - One of the best experts on this subject based on the ideXlab platform.
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On Flame-front instability at elevated pressures
Proceedings of the Combustion Institute, 2007Co-Authors: Jiao Yuan, Chung King LawAbstract:Abstract Effects of pressure up to 3 atm on Flame-front instability were numerically investigated for both linear and nonlinear growth stages at sub-unity and unity Lewis numbers. A sixth-order compact scheme and non-reflecting boundary conditions were used to capture the evolution of the Flame front. Results show that in the linear instability growth stage, elevated pressure can extend the unstable range of Flame-fronts and generate the fine Flame Cell structure. This effect can be qualitatively predicted by the theories when Le = 1.0; however the theories diverge at sub-unity Lewis numbers (e.g. Le = 0.7). In the nonlinear growth stage, the critical wave number (kc) from the linear dispersion relation can be used as a reference length scale for the evolution of the Flame Cell structure. Since elevated pressure increases the critical wave number, small Flame Cells appear over large Flame Cells (deep folds) at high ambient pressures. Furthermore, Flame-front hydrodynamic instability is excited when the lateral domain is enlarged.
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Pulsating and hydrodynamic instabilities at large Lewis numbers
Combustion and Flame, 2005Co-Authors: Jiao Yuan, Chung King LawAbstract:The dynamic behavior of freely propagating premixed Flames with large Lewis numbers was computationally simulated using a sixth-order central difference scheme and nonreflective boundary conditions. Results in the linear stage of the instability growth show that the growth rate dramatically decreases with increasing Lewis number and that the large activation energy excites the pulsating instability and increases the growth rate of the hydrodynamic instability. In the nonlinear growth stage, there exist regimes of stable Cell propagation, periodic pulsating Cellular Flames, and irregular pulsating Cellular Flames as the activation energy is increased. Characteristics of these regimes were further studied for the effects of Lewis number on the Flame front structure in the regime of stable Cell propagation, the effects of Flame pulsation on the flow and Flame Cell structure in the regime of periodic pulsating Cellular Flame, and the complex pattern formation in the regime of irregular pulsating Cellular Flame. It is further demonstrated that unsteady pulsating Flames can propagate faster than the adiabatic Flame when the local stretch rate is positive, implying that models based on quasi-steady Flame propagation may not correctly predict the behavior of unsteady Flames with large Lewis numbers.
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coupled hydrodynamic and diffusional thermal instabilities in Flame propagation at subunity lewis numbers
Physics of Fluids, 2005Co-Authors: Jiao Yuan, Chung King LawAbstract:The dynamics of Flame Cell evolution due to the coupling between hydrodynamic and diffusional-thermal instabilities in subunity Lewis number Flames was simulated using a sixth-order central difference scheme and newly developed nonreflective boundary conditions. Results show that the interaction between these two modes of instabilities yields distinct evolutions of Cell splitting, merging, growth, local extinction, and lateral motion, leading to fluctuations of the flow and species concentrations as well as substantial increase in the Flame speed. The study also demonstrates that small computational domains cannot correctly predict Cell merging and transverse motion.
Laura Valverdeislas - One of the best experts on this subject based on the ideXlab platform.
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androgens exert a cysticidal effect upon taenia crassiceps by disrupting Flame Cell morphology and function
PLOS ONE, 2015Co-Authors: Javier R. Ambrosio, Olivia Reynosoducoing, Karen Elizabeth Navacastro, Pedro Ostoasaloma, Galileo Escobedo, Azucena Ruizrosado, Laura Valverdeislas, Isabel Palacios M Arreola, Lenin DominguezramirezAbstract:The effects of testosterone (T4) and dihydrotestosterone (DHT) on the survival of the helminth cestode parasite Taenia crassiceps, as well as their effects on actin, tubulin and myosin expression and their assembly into the excretory system of Flame Cells are described in this paper. In vitro evaluations on parasite viability, flow cytometry, confocal microscopy, video-microscopy of live Flame Cells, and docking experiments of androgens interacting with actin, tubulin, and myosin were conducted. Our results show that T4 and DHT reduce T. crassiceps viability in a dose- and time-dependent fashion, reaching 90% of mortality at the highest dose used (40 ng/ml) and time exposed (10 days) in culture. Androgen treatment does not induce differences in the specific expression pattern of actin, tubulin, and myosin isoforms as compared with control parasites. Confocal microscopy demonstrated a strong disruption of the parasite tegument, with reduced assembly, shape, and motion of Flame Cells. Docking experiments show that androgens are capable of affecting parasite survival and Flame Cell morphology by directly interacting with actin, tubulin and myosin without altering their protein expression pattern. We show that both T4 and DHT are able to bind actin, tubulin, and myosin affecting their assembly and causing parasite intoxication due to impairment of Flame Cell function. Live Flame Cell video microscopy showing a reduced motion as well changes in the shape of Flame Cells are also shown. In summary, T4 and DHT directly act on T. crassiceps cysticerci through altering parasite survival as well as the assembly and function of Flame Cells.
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visualization and 3d reconstruction of Flame Cells of taenia solium cestoda
PLOS ONE, 2011Co-Authors: Laura Valverdeislas, Olivia Reynosoducoing, Esteban Arrangoiz, Elio Vega, Lilia Robert, Rafael Villanueva, Kaethe Willms, Armando Zepedarodriguez, Teresa I Fortoul, Javier R. AmbrosioAbstract:Background Flame Cells are the terminal Cells of protonephridial systems, which are part of the excretory systems of invertebrates. Although the knowledge of their biological role is incomplete, there is a consensus that these Cells perform excretion/secretion activities. It has been suggested that the Flame Cells participate in the maintenance of the osmotic environment that the cestodes require to live inside their hosts. In live Platyhelminthes, by light microscopy, the Cells appear beating their Flames rapidly and, at the ultrastructural, the Cells have a large body enclosing a tuft of cilia. Few studies have been performed to define the localization of the cytoskeletal proteins of these Cells, and it is unclear how these proteins are involved in Cell function. Methodology/Principal Findings Parasites of two different developmental stages of T. solium were used: cysticerci recovered from naturally infected pigs and intestinal adults obtained from immunosuppressed and experimentally infected golden hamsters. Hamsters were fed viable cysticerci to recover adult parasites after one month of infection. In the present studies focusing on Flame Cells of cysticerci tissues was performed. Using several methods such as video, confocal and electron microscopy, in addition to computational analysis for reconstruction and modeling, we have provided a 3D visual rendition of the cytoskeletal architecture of Taenia solium Flame Cells. Conclusions/Significance We consider that visual representations of Cells open a new way for understanding the role of these Cells in the excretory systems of Platyhelminths. After reconstruction, the observation of high resolution 3D images allowed for virtual observation of the interior composition of Cells. A combination of microscopic images, computational reconstructions and 3D modeling of Cells appears to be useful for inferring the Cellular dynamics of the Flame Cell cytoskeleton.