The Experts below are selected from a list of 72 Experts worldwide ranked by ideXlab platform
Kazutsugu Hirayama - One of the best experts on this subject based on the ideXlab platform.
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Resting eggs of the marine rotifer Brachionus plicatilis Muller: development, and effect of irradiation on hatching
Hydrobiologia, 1995Co-Authors: Atsushi Hagiwara, Nobuyuki Hoshi, Fumiko Kawahara, Kayoko Tominaga, Kazutsugu HirayamaAbstract:Diapause and hatching of Brachionus plicatilis Muller resting eggs were examined through histological and optical approaches. Compound microscope observations on 1% toluidine blue-stained Embryo sections suggests that the total number of nuclei in an Embryo during the internal diapause period increased from 22 on Day 2 to 39 (each n = 1) on Day 6. The outer layer of Embryo Membrane gradually thickens from 1.2 (Day 0) to 4.0 μm (Day 8) (each n = 10).
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Resting eggs of the marine rotifer Brachionus plicatilis Müller: development, and effect of irradiation on hatching
Hydrobiologia, 1995Co-Authors: Atsushi Hagiwara, Nobuyuki Hoshi, Fumiko Kawahara, Kayoko Tominaga, Kazutsugu HirayamaAbstract:Diapause and hatching of Brachionus plicatilis Müller resting eggs were examined through histological and optical approaches. Compound microscope observations on 1% toluidine blue-stained Embryo sections suggests that the total number of nuclei in an Embryo during the internal diapause period increased from 22 on Day 2 to 39 (each n = 1) on Day 6. The outer layer of Embryo Membrane gradually thickens from 1.2 (Day 0) to 4.0 µm (Day 8) (each n = 10). Resting eggs that have completed maturation and are in the external diapause period require light for hatching. The threshold of light (halogen lamp) intensity for hatching was estimated to be 4400 lux for 30 min. Hatching rate decreased with longer wavelength irradiation (mercury lamp). Irradiation at more than 350 nm caused 1–25% hatching, but it reached 50–60% at 250–310 nm light. The addition of hydrogen peroxide or prostaglandins ( E _1, E _2 or F _2α) caused resting egg hatching even in darkness. The production of peroxide in seawater caused by light as well as the oxidation of fatty acid to prostaglandins inside the Embryo is a possible mechanism of resting egg hatching.
David M Rawson - One of the best experts on this subject based on the ideXlab platform.
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Ultrasound enhanced methanol penetration of zebrafish (Danio rerio) Embryos measured by permittivity changes using impedance spectroscopy
European Biophysics Journal, 2008Co-Authors: Robert Y. Wang, David M Rawson, Mo Guan, Tiantian ZhangAbstract:Studies on permittivity changes in fish Embryos measured by impedance spectroscopy after ultrasound treatment during exposure to cryoprotectant is reported here for the first time. The permittivity changes of zebrafish Embryos in cryoprotectant solutions before and after ultrasound treatment were measured using impedance spectroscopy. Zebrafish ( Danio rerio ) Embryos at 50% epiboly stage were exposed to 2 M methanol for 25 min before ultrasound treatment for 5 min at 22°C. Embryos were treated with ultrasound in different frequencies (24 and 48 kHz) and voltages (50, 100, 150 and 175 V) combinations. The results showed a clear increasing trend of permittivity from voltage 50 to 175 V over lower impedance frequency range of 10–10^3 Hz indicating increased methanol penetration into the Embryos after ultrasound treatment. The Embryo survival was not compromised after ultrasound treatment under conditions used in the present study. The use of impedance spectroscopy technique provides a useful none-invasive tool for detecting changes of cryoprotectant penetration in fish Embryos after ultrasound treatment. The technique is especially useful for the selection of the suitable cryoprotectants in Embryo cryopreservation and may also allow quantitative measurements in Embryo Membrane permeability studies.
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development of a new rapid measurement technique for fish Embryo Membrane permeability studies using impedance spectroscopy
Theriogenology, 2006Co-Authors: Tiantian Zhang, R Y Wang, David M RawsonAbstract:Information on fish Embryo Membrane permeability is vital in their cryopreservation. Whilst conventional volumetric measurement based assessment methods have been widely used in fish Embryo Membrane permeability studies, they are lengthy and reduce the capacity for multi-Embryo measurement during an experimental run. A new rapid ‘real-time’ measurement technique is required to determine Membrane permeability during cryoprotectant treatment. In this study, zebrafish (Danio rerio) Embryo Membrane permeability to cryoprotectants was investigated using impedance spectroscopy. An Embryo holding cell, capable of holding up to 10 zebrafish Embryos was built incorporating the original system electrods for measuring the impedance spectra. The holding cell was tested with deionised water and a series of KCl solutions with known conductance values to confirm the performance of the modified system. Untreated intact Embryos were then tested to optimise the loading capacity and sensitivity of the system. To study the impedance changes of zebrafish Embryos during cryoprotectant exposure, three, six or nine Embryos at 50% epiboly stage were loaded into the holding cell in egg water, which was then removed and replaced by 0.5, 1.0, 2.0 or 3 M methanol or dimethyl sulfoxide (DMSO). The impedance changes of the loaded Embryos in different cryoprotectant solutions were monitored over 30 min at 22 °C, immediately following Embryo exposure to cryoprotectants, at the frequency range of 10–106 Hz. The impedance changes of the Embryos in egg water were used as controls. Results from this study showed that the optimum Embryo loading level was six Embryos per cell for each experimental run. The optimum frequency was identified at 103.14 or 1380 Hz which provided good sensitivity and reproducibility. Significant impedance changes were detected after Embryos were exposed to different concentrations of cryoprotectants. The results agreed well with those obtained from conventional volumetric based studies.
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Study on fish Embryo responses to the treatment of cryoprotective chemicals using impedance spectroscopy
European Biophysics Journal, 2006Co-Authors: Robert Y. Wang, Tiantian Zhang, David M RawsonAbstract:Investigations using electrical impedance spectroscopy to measure the responses of fish Embryos to the cryoprotective chemicals, methanol and dimethyl sulphoxide (DMSO), were carried out. Zebrafish ( Danio rerio ) Embryos were used as a model to study the newly proposed technique. The normalised permittivity and conductivity changes of the Embryos were measured continuously over a 20-min period in a customised Embryo-holding chamber. The normalised permittivity and conductivity spectra were obtained during Embryo exposure to different concentrations of methanol (1.0, 2.0 and 3.0 M) and DMSO (0.5, 1.0 and 2.0 M) solutions. The results showed significant permittivity and conductivity changes after Embryo exposure to methanol and DMSO at the optimum Embryo loading level (six Embryos). Embryos in different concentrations of methanol and DMSO also resulted in quantitative responses shown in the normalised permittivity and conductivity spectra. The results demonstrated that fish Embryo Membrane permeability to cryoprotective chemicals could be monitored in real-time. The measurement of permittivity at a lower frequency range (10–10^3 Hz) and conductivity at a higher frequency range (10^4–10^6 Hz) during fish Embryo exposure to cryoprotective chemicals using impedance spectroscopy can be used as a new tool for the fast screening of most effective cryoprotective chemicals. The results from the present study also demonstrated the possibility of quantifying the level of cryoprotective chemicals penetrating the fish Embryos.
Tiantian Zhang - One of the best experts on this subject based on the ideXlab platform.
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Ultrasound enhanced methanol penetration of zebrafish (Danio rerio) Embryos measured by permittivity changes using impedance spectroscopy
European Biophysics Journal, 2008Co-Authors: Robert Y. Wang, David M Rawson, Mo Guan, Tiantian ZhangAbstract:Studies on permittivity changes in fish Embryos measured by impedance spectroscopy after ultrasound treatment during exposure to cryoprotectant is reported here for the first time. The permittivity changes of zebrafish Embryos in cryoprotectant solutions before and after ultrasound treatment were measured using impedance spectroscopy. Zebrafish ( Danio rerio ) Embryos at 50% epiboly stage were exposed to 2 M methanol for 25 min before ultrasound treatment for 5 min at 22°C. Embryos were treated with ultrasound in different frequencies (24 and 48 kHz) and voltages (50, 100, 150 and 175 V) combinations. The results showed a clear increasing trend of permittivity from voltage 50 to 175 V over lower impedance frequency range of 10–10^3 Hz indicating increased methanol penetration into the Embryos after ultrasound treatment. The Embryo survival was not compromised after ultrasound treatment under conditions used in the present study. The use of impedance spectroscopy technique provides a useful none-invasive tool for detecting changes of cryoprotectant penetration in fish Embryos after ultrasound treatment. The technique is especially useful for the selection of the suitable cryoprotectants in Embryo cryopreservation and may also allow quantitative measurements in Embryo Membrane permeability studies.
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development of a new rapid measurement technique for fish Embryo Membrane permeability studies using impedance spectroscopy
Theriogenology, 2006Co-Authors: Tiantian Zhang, R Y Wang, David M RawsonAbstract:Information on fish Embryo Membrane permeability is vital in their cryopreservation. Whilst conventional volumetric measurement based assessment methods have been widely used in fish Embryo Membrane permeability studies, they are lengthy and reduce the capacity for multi-Embryo measurement during an experimental run. A new rapid ‘real-time’ measurement technique is required to determine Membrane permeability during cryoprotectant treatment. In this study, zebrafish (Danio rerio) Embryo Membrane permeability to cryoprotectants was investigated using impedance spectroscopy. An Embryo holding cell, capable of holding up to 10 zebrafish Embryos was built incorporating the original system electrods for measuring the impedance spectra. The holding cell was tested with deionised water and a series of KCl solutions with known conductance values to confirm the performance of the modified system. Untreated intact Embryos were then tested to optimise the loading capacity and sensitivity of the system. To study the impedance changes of zebrafish Embryos during cryoprotectant exposure, three, six or nine Embryos at 50% epiboly stage were loaded into the holding cell in egg water, which was then removed and replaced by 0.5, 1.0, 2.0 or 3 M methanol or dimethyl sulfoxide (DMSO). The impedance changes of the loaded Embryos in different cryoprotectant solutions were monitored over 30 min at 22 °C, immediately following Embryo exposure to cryoprotectants, at the frequency range of 10–106 Hz. The impedance changes of the Embryos in egg water were used as controls. Results from this study showed that the optimum Embryo loading level was six Embryos per cell for each experimental run. The optimum frequency was identified at 103.14 or 1380 Hz which provided good sensitivity and reproducibility. Significant impedance changes were detected after Embryos were exposed to different concentrations of cryoprotectants. The results agreed well with those obtained from conventional volumetric based studies.
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Study on fish Embryo responses to the treatment of cryoprotective chemicals using impedance spectroscopy
European Biophysics Journal, 2006Co-Authors: Robert Y. Wang, Tiantian Zhang, David M RawsonAbstract:Investigations using electrical impedance spectroscopy to measure the responses of fish Embryos to the cryoprotective chemicals, methanol and dimethyl sulphoxide (DMSO), were carried out. Zebrafish ( Danio rerio ) Embryos were used as a model to study the newly proposed technique. The normalised permittivity and conductivity changes of the Embryos were measured continuously over a 20-min period in a customised Embryo-holding chamber. The normalised permittivity and conductivity spectra were obtained during Embryo exposure to different concentrations of methanol (1.0, 2.0 and 3.0 M) and DMSO (0.5, 1.0 and 2.0 M) solutions. The results showed significant permittivity and conductivity changes after Embryo exposure to methanol and DMSO at the optimum Embryo loading level (six Embryos). Embryos in different concentrations of methanol and DMSO also resulted in quantitative responses shown in the normalised permittivity and conductivity spectra. The results demonstrated that fish Embryo Membrane permeability to cryoprotective chemicals could be monitored in real-time. The measurement of permittivity at a lower frequency range (10–10^3 Hz) and conductivity at a higher frequency range (10^4–10^6 Hz) during fish Embryo exposure to cryoprotective chemicals using impedance spectroscopy can be used as a new tool for the fast screening of most effective cryoprotective chemicals. The results from the present study also demonstrated the possibility of quantifying the level of cryoprotective chemicals penetrating the fish Embryos.
Atsushi Hagiwara - One of the best experts on this subject based on the ideXlab platform.
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Resting eggs of the marine rotifer Brachionus plicatilis Muller: development, and effect of irradiation on hatching
Hydrobiologia, 1995Co-Authors: Atsushi Hagiwara, Nobuyuki Hoshi, Fumiko Kawahara, Kayoko Tominaga, Kazutsugu HirayamaAbstract:Diapause and hatching of Brachionus plicatilis Muller resting eggs were examined through histological and optical approaches. Compound microscope observations on 1% toluidine blue-stained Embryo sections suggests that the total number of nuclei in an Embryo during the internal diapause period increased from 22 on Day 2 to 39 (each n = 1) on Day 6. The outer layer of Embryo Membrane gradually thickens from 1.2 (Day 0) to 4.0 μm (Day 8) (each n = 10).
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Resting eggs of the marine rotifer Brachionus plicatilis Müller: development, and effect of irradiation on hatching
Hydrobiologia, 1995Co-Authors: Atsushi Hagiwara, Nobuyuki Hoshi, Fumiko Kawahara, Kayoko Tominaga, Kazutsugu HirayamaAbstract:Diapause and hatching of Brachionus plicatilis Müller resting eggs were examined through histological and optical approaches. Compound microscope observations on 1% toluidine blue-stained Embryo sections suggests that the total number of nuclei in an Embryo during the internal diapause period increased from 22 on Day 2 to 39 (each n = 1) on Day 6. The outer layer of Embryo Membrane gradually thickens from 1.2 (Day 0) to 4.0 µm (Day 8) (each n = 10). Resting eggs that have completed maturation and are in the external diapause period require light for hatching. The threshold of light (halogen lamp) intensity for hatching was estimated to be 4400 lux for 30 min. Hatching rate decreased with longer wavelength irradiation (mercury lamp). Irradiation at more than 350 nm caused 1–25% hatching, but it reached 50–60% at 250–310 nm light. The addition of hydrogen peroxide or prostaglandins ( E _1, E _2 or F _2α) caused resting egg hatching even in darkness. The production of peroxide in seawater caused by light as well as the oxidation of fatty acid to prostaglandins inside the Embryo is a possible mechanism of resting egg hatching.
Robert Y. Wang - One of the best experts on this subject based on the ideXlab platform.
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Ultrasound enhanced methanol penetration of zebrafish (Danio rerio) Embryos measured by permittivity changes using impedance spectroscopy
European Biophysics Journal, 2008Co-Authors: Robert Y. Wang, David M Rawson, Mo Guan, Tiantian ZhangAbstract:Studies on permittivity changes in fish Embryos measured by impedance spectroscopy after ultrasound treatment during exposure to cryoprotectant is reported here for the first time. The permittivity changes of zebrafish Embryos in cryoprotectant solutions before and after ultrasound treatment were measured using impedance spectroscopy. Zebrafish ( Danio rerio ) Embryos at 50% epiboly stage were exposed to 2 M methanol for 25 min before ultrasound treatment for 5 min at 22°C. Embryos were treated with ultrasound in different frequencies (24 and 48 kHz) and voltages (50, 100, 150 and 175 V) combinations. The results showed a clear increasing trend of permittivity from voltage 50 to 175 V over lower impedance frequency range of 10–10^3 Hz indicating increased methanol penetration into the Embryos after ultrasound treatment. The Embryo survival was not compromised after ultrasound treatment under conditions used in the present study. The use of impedance spectroscopy technique provides a useful none-invasive tool for detecting changes of cryoprotectant penetration in fish Embryos after ultrasound treatment. The technique is especially useful for the selection of the suitable cryoprotectants in Embryo cryopreservation and may also allow quantitative measurements in Embryo Membrane permeability studies.
-
Study on fish Embryo responses to the treatment of cryoprotective chemicals using impedance spectroscopy
European Biophysics Journal, 2006Co-Authors: Robert Y. Wang, Tiantian Zhang, David M RawsonAbstract:Investigations using electrical impedance spectroscopy to measure the responses of fish Embryos to the cryoprotective chemicals, methanol and dimethyl sulphoxide (DMSO), were carried out. Zebrafish ( Danio rerio ) Embryos were used as a model to study the newly proposed technique. The normalised permittivity and conductivity changes of the Embryos were measured continuously over a 20-min period in a customised Embryo-holding chamber. The normalised permittivity and conductivity spectra were obtained during Embryo exposure to different concentrations of methanol (1.0, 2.0 and 3.0 M) and DMSO (0.5, 1.0 and 2.0 M) solutions. The results showed significant permittivity and conductivity changes after Embryo exposure to methanol and DMSO at the optimum Embryo loading level (six Embryos). Embryos in different concentrations of methanol and DMSO also resulted in quantitative responses shown in the normalised permittivity and conductivity spectra. The results demonstrated that fish Embryo Membrane permeability to cryoprotective chemicals could be monitored in real-time. The measurement of permittivity at a lower frequency range (10–10^3 Hz) and conductivity at a higher frequency range (10^4–10^6 Hz) during fish Embryo exposure to cryoprotective chemicals using impedance spectroscopy can be used as a new tool for the fast screening of most effective cryoprotective chemicals. The results from the present study also demonstrated the possibility of quantifying the level of cryoprotective chemicals penetrating the fish Embryos.