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Christian Wiencke - One of the best experts on this subject based on the ideXlab platform.
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a Monochromatic action spectrum for the photoinduction of the uv absorbing mycosporine like amino acid shinorine in the red alga chondrus crispus
Photochemistry and Photobiology, 2004Co-Authors: Gudrun Krabs, Masakatsu Watanabe, Christian WienckeAbstract:To determine the action spectrum for photoinduction of the ultraviolet (UV)-absorbing mycosporine-like amino acid shinorine, specimens of the marine red alga Chondrus crispus were irradiated with Monochromatic Light of various wavelengths using the Okazaki large spectrograph at the National Institute for Basic Biology, Okazaki, Japan. Fluence response curves were determined for the wavelengths between 280 and 750 nm, by irradiating the algae with Monochromatic Light for 10 h, followed by 4 h of 25 micromol m(-2) s(-1) photosynthetically active radiation and 10 h darkness. Samples were taken after the second exposure interval. A linear correlation between fluence rate and accumulated shinorine concentration was detected for wavelengths between 350 and 490 nm in the fluence rate range of 20-30 micromol m(-2) s(-1), whereas there was no induction above 490 nm. Below 350 nm a decline in shinorine concentration could be observed at fluence rates above 30 micromol m(-2) s(-1), probably due to an inhibition of photosynthetic activity and a subsequent impairment of shinorine biosynthesis. The constructed action spectrum indicated that the photoreceptors mediating shinorine photoinduction might be an unidentified UV-A-type photoreceptor with absorption peaks at 320, 340 and 400 nm.
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a Monochromatic action spectrum for the photoinduction of the uv absorbing mycosporine like amino acid shinorine in the red alga chondrus crispus
Photochemistry and Photobiology, 2004Co-Authors: Gudrun Krabs, Masakatsu Watanabe, Christian WienckeAbstract:Abstract To determine the action spectrum for photoinduction of the ultraviolet (UV)-absorbing mycosporine-like amino acid shinorine, specimens of the marine red alga Chondrus crispus were irradiated with Monochromatic Light of various wavelengths using the Okazaki large spectrograph at the National Institute for Basic Biology, Okazaki, Japan. Fluence response curves were determined for the wavelengths between 280 and 750 nm, by irradiating the algae with Monochromatic Light for 10 h, followed by 4 h of 25 μmol m−2 s−1 photosynthetically active radiation and 10 h darkness. Samples were taken after the second exposure interval. A linear correlation between fluence rate and accumulated shinorine concentration was detected for wavelengths between 350 and 490 nm in the fluence rate range of 20–30 μmol m−2 s−1, whereas there was no induction above 490 nm. Below 350 nm a decline in shinorine concentration could be observed at fluence rates above 30 μmol m−2 s−1, probably due to an inhibition of photosynthetic a...
Masakatsu Watanabe - One of the best experts on this subject based on the ideXlab platform.
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a Monochromatic action spectrum for the photoinduction of the uv absorbing mycosporine like amino acid shinorine in the red alga chondrus crispus
Photochemistry and Photobiology, 2004Co-Authors: Gudrun Krabs, Masakatsu Watanabe, Christian WienckeAbstract:To determine the action spectrum for photoinduction of the ultraviolet (UV)-absorbing mycosporine-like amino acid shinorine, specimens of the marine red alga Chondrus crispus were irradiated with Monochromatic Light of various wavelengths using the Okazaki large spectrograph at the National Institute for Basic Biology, Okazaki, Japan. Fluence response curves were determined for the wavelengths between 280 and 750 nm, by irradiating the algae with Monochromatic Light for 10 h, followed by 4 h of 25 micromol m(-2) s(-1) photosynthetically active radiation and 10 h darkness. Samples were taken after the second exposure interval. A linear correlation between fluence rate and accumulated shinorine concentration was detected for wavelengths between 350 and 490 nm in the fluence rate range of 20-30 micromol m(-2) s(-1), whereas there was no induction above 490 nm. Below 350 nm a decline in shinorine concentration could be observed at fluence rates above 30 micromol m(-2) s(-1), probably due to an inhibition of photosynthetic activity and a subsequent impairment of shinorine biosynthesis. The constructed action spectrum indicated that the photoreceptors mediating shinorine photoinduction might be an unidentified UV-A-type photoreceptor with absorption peaks at 320, 340 and 400 nm.
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a Monochromatic action spectrum for the photoinduction of the uv absorbing mycosporine like amino acid shinorine in the red alga chondrus crispus
Photochemistry and Photobiology, 2004Co-Authors: Gudrun Krabs, Masakatsu Watanabe, Christian WienckeAbstract:Abstract To determine the action spectrum for photoinduction of the ultraviolet (UV)-absorbing mycosporine-like amino acid shinorine, specimens of the marine red alga Chondrus crispus were irradiated with Monochromatic Light of various wavelengths using the Okazaki large spectrograph at the National Institute for Basic Biology, Okazaki, Japan. Fluence response curves were determined for the wavelengths between 280 and 750 nm, by irradiating the algae with Monochromatic Light for 10 h, followed by 4 h of 25 μmol m−2 s−1 photosynthetically active radiation and 10 h darkness. Samples were taken after the second exposure interval. A linear correlation between fluence rate and accumulated shinorine concentration was detected for wavelengths between 350 and 490 nm in the fluence rate range of 20–30 μmol m−2 s−1, whereas there was no induction above 490 nm. Below 350 nm a decline in shinorine concentration could be observed at fluence rates above 30 μmol m−2 s−1, probably due to an inhibition of photosynthetic a...
Anna Wirzjustice - One of the best experts on this subject based on the ideXlab platform.
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high sensitivity of human melatonin alertness thermoregulation and heart rate to short wavelength Light
The Journal of Clinical Endocrinology and Metabolism, 2005Co-Authors: Christian Cajochen, Mirjam Munch, Szymon Kobialka, Kurt Krauchi, Roland Steiner, P Oelhafen, Selim Orgul, Anna WirzjusticeAbstract:Light can elicit acute physiological and alerting responses in humans, the magnitude of which depends on the timing, intensity, and duration of Light exposure. Here, we report that the alerting response of Light as well as its effects on thermoregulation and heart rate are also wavelength dependent. Exposure to 2 h of Monochromatic Light at 460 nm in the late evening induced a significantly greater melatonin suppression than occurred with 550-nm Monochromatic Light, concomitant with a significantly greater alerting response and increased core body temperature and heart rate (∼2.8 × 1013 photons/cm2/sec for each Light treatment). Light diminished the distal-proximal skin temperature gradient, a measure of the degree of vasoconstriction, independent of wavelength. Nonclassical ocular photoreceptors with peak sensitivity around 460 nm have been found to regulate circadian rhythm function as measured by melatonin suppression and phase shifting. Our findings—that the sensitivity of the human alerting response ...
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high sensitivity of human melatonin alertness thermoregulation and heart rate to short wavelength Light
The Journal of Clinical Endocrinology and Metabolism, 2005Co-Authors: Christian Cajochen, Mirjam Munch, Szymon Kobialka, Kurt Krauchi, Roland Steiner, P Oelhafen, Selim Orgul, Anna WirzjusticeAbstract:Light can elicit acute physiological and alerting responses in humans, the magnitude of which depends on the timing, intensity, and duration of Light exposure. Here, we report that the alerting response of Light as well as its effects on thermoregulation and heart rate are also wavelength dependent. Exposure to 2 h of Monochromatic Light at 460 nm in the late evening induced a significantly greater melatonin suppression than occurred with 550-nm Monochromatic Light, concomitant with a significantly greater alerting response and increased core body temperature and heart rate ( approximately 2.8 x 10(13) photons/cm(2)/sec for each Light treatment). Light diminished the distal-proximal skin temperature gradient, a measure of the degree of vasoconstriction, independent of wavelength. Nonclassical ocular photoreceptors with peak sensitivity around 460 nm have been found to regulate circadian rhythm function as measured by melatonin suppression and phase shifting. Our findings-that the sensitivity of the human alerting response to Light and its thermoregulatory sequelae are blue-shifted relative to the three-cone visual photopic system-indicate an additional role for these novel photoreceptors in modifying human alertness, thermophysiology, and heart rate.
Gudrun Krabs - One of the best experts on this subject based on the ideXlab platform.
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a Monochromatic action spectrum for the photoinduction of the uv absorbing mycosporine like amino acid shinorine in the red alga chondrus crispus
Photochemistry and Photobiology, 2004Co-Authors: Gudrun Krabs, Masakatsu Watanabe, Christian WienckeAbstract:To determine the action spectrum for photoinduction of the ultraviolet (UV)-absorbing mycosporine-like amino acid shinorine, specimens of the marine red alga Chondrus crispus were irradiated with Monochromatic Light of various wavelengths using the Okazaki large spectrograph at the National Institute for Basic Biology, Okazaki, Japan. Fluence response curves were determined for the wavelengths between 280 and 750 nm, by irradiating the algae with Monochromatic Light for 10 h, followed by 4 h of 25 micromol m(-2) s(-1) photosynthetically active radiation and 10 h darkness. Samples were taken after the second exposure interval. A linear correlation between fluence rate and accumulated shinorine concentration was detected for wavelengths between 350 and 490 nm in the fluence rate range of 20-30 micromol m(-2) s(-1), whereas there was no induction above 490 nm. Below 350 nm a decline in shinorine concentration could be observed at fluence rates above 30 micromol m(-2) s(-1), probably due to an inhibition of photosynthetic activity and a subsequent impairment of shinorine biosynthesis. The constructed action spectrum indicated that the photoreceptors mediating shinorine photoinduction might be an unidentified UV-A-type photoreceptor with absorption peaks at 320, 340 and 400 nm.
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a Monochromatic action spectrum for the photoinduction of the uv absorbing mycosporine like amino acid shinorine in the red alga chondrus crispus
Photochemistry and Photobiology, 2004Co-Authors: Gudrun Krabs, Masakatsu Watanabe, Christian WienckeAbstract:Abstract To determine the action spectrum for photoinduction of the ultraviolet (UV)-absorbing mycosporine-like amino acid shinorine, specimens of the marine red alga Chondrus crispus were irradiated with Monochromatic Light of various wavelengths using the Okazaki large spectrograph at the National Institute for Basic Biology, Okazaki, Japan. Fluence response curves were determined for the wavelengths between 280 and 750 nm, by irradiating the algae with Monochromatic Light for 10 h, followed by 4 h of 25 μmol m−2 s−1 photosynthetically active radiation and 10 h darkness. Samples were taken after the second exposure interval. A linear correlation between fluence rate and accumulated shinorine concentration was detected for wavelengths between 350 and 490 nm in the fluence rate range of 20–30 μmol m−2 s−1, whereas there was no induction above 490 nm. Below 350 nm a decline in shinorine concentration could be observed at fluence rates above 30 μmol m−2 s−1, probably due to an inhibition of photosynthetic a...
Christian Cajochen - One of the best experts on this subject based on the ideXlab platform.
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high sensitivity of human melatonin alertness thermoregulation and heart rate to short wavelength Light
The Journal of Clinical Endocrinology and Metabolism, 2005Co-Authors: Christian Cajochen, Mirjam Munch, Szymon Kobialka, Kurt Krauchi, Roland Steiner, P Oelhafen, Selim Orgul, Anna WirzjusticeAbstract:Light can elicit acute physiological and alerting responses in humans, the magnitude of which depends on the timing, intensity, and duration of Light exposure. Here, we report that the alerting response of Light as well as its effects on thermoregulation and heart rate are also wavelength dependent. Exposure to 2 h of Monochromatic Light at 460 nm in the late evening induced a significantly greater melatonin suppression than occurred with 550-nm Monochromatic Light, concomitant with a significantly greater alerting response and increased core body temperature and heart rate (∼2.8 × 1013 photons/cm2/sec for each Light treatment). Light diminished the distal-proximal skin temperature gradient, a measure of the degree of vasoconstriction, independent of wavelength. Nonclassical ocular photoreceptors with peak sensitivity around 460 nm have been found to regulate circadian rhythm function as measured by melatonin suppression and phase shifting. Our findings—that the sensitivity of the human alerting response ...
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high sensitivity of human melatonin alertness thermoregulation and heart rate to short wavelength Light
The Journal of Clinical Endocrinology and Metabolism, 2005Co-Authors: Christian Cajochen, Mirjam Munch, Szymon Kobialka, Kurt Krauchi, Roland Steiner, P Oelhafen, Selim Orgul, Anna WirzjusticeAbstract:Light can elicit acute physiological and alerting responses in humans, the magnitude of which depends on the timing, intensity, and duration of Light exposure. Here, we report that the alerting response of Light as well as its effects on thermoregulation and heart rate are also wavelength dependent. Exposure to 2 h of Monochromatic Light at 460 nm in the late evening induced a significantly greater melatonin suppression than occurred with 550-nm Monochromatic Light, concomitant with a significantly greater alerting response and increased core body temperature and heart rate ( approximately 2.8 x 10(13) photons/cm(2)/sec for each Light treatment). Light diminished the distal-proximal skin temperature gradient, a measure of the degree of vasoconstriction, independent of wavelength. Nonclassical ocular photoreceptors with peak sensitivity around 460 nm have been found to regulate circadian rhythm function as measured by melatonin suppression and phase shifting. Our findings-that the sensitivity of the human alerting response to Light and its thermoregulatory sequelae are blue-shifted relative to the three-cone visual photopic system-indicate an additional role for these novel photoreceptors in modifying human alertness, thermophysiology, and heart rate.