The Experts below are selected from a list of 219 Experts worldwide ranked by ideXlab platform

Pedro J Aparicio - One of the best experts on this subject based on the ideXlab platform.

  • blue Light Requirement for the biosynthesis of an no2 transport system in the chlamydomonas reinhardtii nitrate transport mutant s10
    Plant Cell and Environment, 1999
    Co-Authors: Miguel Angel Quinones, Aurora Galván, Emilio Fernández, Pedro J Aparicio
    Abstract:

    The blue-Light Requirement for the biosynthesis of nitrite reductase and an NO2– transport system was studied in Chlamydomonas reinhardtii mutant S10. The only oxidized nitrogen species that could be taken up by this mutant was NO2–, due to the presence of NO2– transport systems and the absence of high-affinity NO3– transporters. NH4+-grown cells required illumination with blue Light to recover the ability to take up NO2– when resuspended in an NO2–-containing NH4+-deprived medium. This blue-Light- dependent recovery, which took 1 h, could be suppressed by cycloheximide, indicating that protein biosynthesis was involved. The biosynthesis of nitrite reductase took place in cell suspensions irradiated with red Light, even in the absence of NO2–, thus suggesting that the process requiring blue Light was the biosynthesis of an NO2– transport system. Nitrite reductase-containing cells (pre-irradiated with red Light) took 1 h to start consuming NO2– when they were additionally irradiated with blue Light in the presence of this anion, and this process was also cycloheximide-sensitive. The NO2– transport system operated either under red plus blue Light or red Light only. Thus, in C. reinhardtii mutant S10 cells, blue Light was only required for the biosynthesis of an NO2– transport system and not for its activity.

  • Blue‐Light Requirement for the biosynthesis of an NO2− transport system in the Chlamydomonas reinhardtii nitrate transport mutant S10*
    Plant Cell & Environment, 1999
    Co-Authors: Miguel Angel Quinones, Aurora Galván, Emilio Fernández, Pedro J Aparicio
    Abstract:

    The blue-Light Requirement for the biosynthesis of nitrite reductase and an NO2– transport system was studied in Chlamydomonas reinhardtii mutant S10. The only oxidized nitrogen species that could be taken up by this mutant was NO2–, due to the presence of NO2– transport systems and the absence of high-affinity NO3– transporters. NH4+-grown cells required illumination with blue Light to recover the ability to take up NO2– when resuspended in an NO2–-containing NH4+-deprived medium. This blue-Light- dependent recovery, which took 1 h, could be suppressed by cycloheximide, indicating that protein biosynthesis was involved. The biosynthesis of nitrite reductase took place in cell suspensions irradiated with red Light, even in the absence of NO2–, thus suggesting that the process requiring blue Light was the biosynthesis of an NO2– transport system. Nitrite reductase-containing cells (pre-irradiated with red Light) took 1 h to start consuming NO2– when they were additionally irradiated with blue Light in the presence of this anion, and this process was also cycloheximide-sensitive. The NO2– transport system operated either under red plus blue Light or red Light only. Thus, in C. reinhardtii mutant S10 cells, blue Light was only required for the biosynthesis of an NO2– transport system and not for its activity.

  • blue Light Requirement for hc03 uptake and its action spectrum in monoraphidium braunii
    Photochemistry and Photobiology, 1998
    Co-Authors: Nuria Giraldez, Pedro J Aparicio, Miguel Angel Quinones
    Abstract:

    The uptake and assimilation of HCO3 by the green unicellular alga Monoraphidium braunii can be monitored by the alkalinization of the external medium or by the O2 evolution associated with the uptake and reduction of this anion. The activation of HCO3 uptake in this microalga required the irradiation of the cell suspensions with low photon fluence rates of short wavelength radiation. Thus, when the cells were irradiated with strong red Light in the presence of HCO3, very little alkalinization of the external medium or O2 evolution could be observed. The O2 evolution rates measured under red Light could be due to the assimilation of the CO2 derived from the HCO3 present in the medium. The blue Light-dependent O2 evolution rates were not diminished by a periplasmic carbonic anhydrase inhibitor, suggesting that HCO3 -dependent O2 evolution was due to the photoactivation of a selective HCO3 uptake system at the plasma membrane. The action spectrum for HCO3- uptake in M. braunii was very similar to those reported for NO3- and CI- suggested that a flavoprotein may be the photoreceptor for this response.

Thijs L. Pons - One of the best experts on this subject based on the ideXlab platform.

  • gap effects on leaf traits of tropical rainforest trees differing in juvenile Light Requirement
    Oecologia, 2014
    Co-Authors: Nico C. Houter, Thijs L. Pons
    Abstract:

    The relationships of 16 leaf traits and their plasticity with the dependence of tree species on gaps for regeneration (gap association index; GAI) were examined in a Neotropical rainforest. Young saplings of 24 species with varying GAI were grown under a closed canopy, in a medium-sized and in a large gap, thus capturing the full range of plasticity with respect to canopy openness. Structural, biomechanical, chemical and photosynthetic traits were measured. At the chloroplast level, the chlorophyll a/b ratio and plasticity in this variable were not related to the GAI. However, plasticity in total carotenoids per unit chlorophyll was larger in shade-tolerant species. At the leaf level, leaf mass per unit area (LMA) decreased with the GAI under the closed canopy and in the medium gap, but did not significantly decrease with the GAI in the large gap. This was a reflection of the larger plasticity in LMA and leaf thickness of gap-dependent species. The well-known opposite trends in LMA for adaptation and acclimation to high irradiance in evergreen tropical trees were thus not invariably found. Although leaf strength was dependent on LMA and thickness, plasticity in this trait was not related to the GAI. Photosynthetic capacity expressed on each basis increased with the GAI, but the large plasticity in these traits was not clearly related to the GAI. Although gap-dependent species tended to have a greater plasticity overall, as evident from a principle component analysis, leaf traits of gap-dependent species are thus not invariably more phenotypically plastic.

  • Ontogenetic changes in leaf traits of tropical rainforest trees differing in juvenile Light Requirement
    Oecologia, 2012
    Co-Authors: Nico C. Houter, Thijs L. Pons
    Abstract:

    Relationships between leaf traits and the gap dependence for regeneration, and ontogenetic changes therein, were investigated in juvenile and adult tropical rainforest tree species. The juveniles of the 17 species included in the study were grown in high Light, similar to the exposed crowns of the adult trees. The traits were structural, biomechanical, chemical and photosynthetic. With increasing species gap dependence, leaf mass per area (LMA) decreased only sLightly in juveniles and remained constant in adults, whereas punch strength together with tissue density decreased, and photosynthetic capacity and chlorophyll increased. Contrary to what has been mostly found in evergreen tropical rainforest, the trade-off between investment in longevity and in productivity was evident at an essentially constant LMA. Of the traits pertaining to the chloroplast level, photosynthetic capacity per unit chlorophyll increased with gap dependence, but the chlorophyll a / b ratio showed no relationship. Adults had a twofold higher LMA, but leaf strength was on average only about 50% larger. Leaf tissue density, and chlorophyll and leaf N per area were also higher, whereas chlorophyll and leaf N per unit dry mass were lower. Ranking of the species, relationships between traits and with the gap dependence of the species were similar for juveniles and adults. However, the magnitudes of most ontogenetic changes were not clearly related to a species’ gap dependence. The adaptive value of the leaf traits for juveniles and adults is discussed.

  • ontogenetic changes in leaf traits of tropical rainforest trees differing in juvenile Light Requirement
    Oecologia, 2012
    Co-Authors: Nico C. Houter, Thijs L. Pons
    Abstract:

    Relationships between leaf traits and the gap dependence for regeneration, and ontogenetic changes therein, were investigated in juvenile and adult tropical rainforest tree species. The juveniles of the 17 species included in the study were grown in high Light, similar to the exposed crowns of the adult trees. The traits were structural, biomechanical, chemical and photosynthetic. With increasing species gap dependence, leaf mass per area (LMA) decreased only sLightly in juveniles and remained constant in adults, whereas punch strength together with tissue density decreased, and photosynthetic capacity and chlorophyll increased. Contrary to what has been mostly found in evergreen tropical rainforest, the trade-off between investment in longevity and in productivity was evident at an essentially constant LMA. Of the traits pertaining to the chloroplast level, photosynthetic capacity per unit chlorophyll increased with gap dependence, but the chlorophyll a/b ratio showed no relationship. Adults had a twofold higher LMA, but leaf strength was on average only about 50% larger. Leaf tissue density, and chlorophyll and leaf N per area were also higher, whereas chlorophyll and leaf N per unit dry mass were lower. Ranking of the species, relationships between traits and with the gap dependence of the species were similar for juveniles and adults. However, the magnitudes of most ontogenetic changes were not clearly related to a species’ gap dependence. The adaptive value of the leaf traits for juveniles and adults is discussed. Electronic supplementary material The online version of this article (doi:10.1007/s00442-011-2175-x) contains supplementary material, which is available to authorized users.

Miguel Angel Quinones - One of the best experts on this subject based on the ideXlab platform.

  • blue Light Requirement for the biosynthesis of an no2 transport system in the chlamydomonas reinhardtii nitrate transport mutant s10
    Plant Cell and Environment, 1999
    Co-Authors: Miguel Angel Quinones, Aurora Galván, Emilio Fernández, Pedro J Aparicio
    Abstract:

    The blue-Light Requirement for the biosynthesis of nitrite reductase and an NO2– transport system was studied in Chlamydomonas reinhardtii mutant S10. The only oxidized nitrogen species that could be taken up by this mutant was NO2–, due to the presence of NO2– transport systems and the absence of high-affinity NO3– transporters. NH4+-grown cells required illumination with blue Light to recover the ability to take up NO2– when resuspended in an NO2–-containing NH4+-deprived medium. This blue-Light- dependent recovery, which took 1 h, could be suppressed by cycloheximide, indicating that protein biosynthesis was involved. The biosynthesis of nitrite reductase took place in cell suspensions irradiated with red Light, even in the absence of NO2–, thus suggesting that the process requiring blue Light was the biosynthesis of an NO2– transport system. Nitrite reductase-containing cells (pre-irradiated with red Light) took 1 h to start consuming NO2– when they were additionally irradiated with blue Light in the presence of this anion, and this process was also cycloheximide-sensitive. The NO2– transport system operated either under red plus blue Light or red Light only. Thus, in C. reinhardtii mutant S10 cells, blue Light was only required for the biosynthesis of an NO2– transport system and not for its activity.

  • Blue‐Light Requirement for the biosynthesis of an NO2− transport system in the Chlamydomonas reinhardtii nitrate transport mutant S10*
    Plant Cell & Environment, 1999
    Co-Authors: Miguel Angel Quinones, Aurora Galván, Emilio Fernández, Pedro J Aparicio
    Abstract:

    The blue-Light Requirement for the biosynthesis of nitrite reductase and an NO2– transport system was studied in Chlamydomonas reinhardtii mutant S10. The only oxidized nitrogen species that could be taken up by this mutant was NO2–, due to the presence of NO2– transport systems and the absence of high-affinity NO3– transporters. NH4+-grown cells required illumination with blue Light to recover the ability to take up NO2– when resuspended in an NO2–-containing NH4+-deprived medium. This blue-Light- dependent recovery, which took 1 h, could be suppressed by cycloheximide, indicating that protein biosynthesis was involved. The biosynthesis of nitrite reductase took place in cell suspensions irradiated with red Light, even in the absence of NO2–, thus suggesting that the process requiring blue Light was the biosynthesis of an NO2– transport system. Nitrite reductase-containing cells (pre-irradiated with red Light) took 1 h to start consuming NO2– when they were additionally irradiated with blue Light in the presence of this anion, and this process was also cycloheximide-sensitive. The NO2– transport system operated either under red plus blue Light or red Light only. Thus, in C. reinhardtii mutant S10 cells, blue Light was only required for the biosynthesis of an NO2– transport system and not for its activity.

  • blue Light Requirement for hc03 uptake and its action spectrum in monoraphidium braunii
    Photochemistry and Photobiology, 1998
    Co-Authors: Nuria Giraldez, Pedro J Aparicio, Miguel Angel Quinones
    Abstract:

    The uptake and assimilation of HCO3 by the green unicellular alga Monoraphidium braunii can be monitored by the alkalinization of the external medium or by the O2 evolution associated with the uptake and reduction of this anion. The activation of HCO3 uptake in this microalga required the irradiation of the cell suspensions with low photon fluence rates of short wavelength radiation. Thus, when the cells were irradiated with strong red Light in the presence of HCO3, very little alkalinization of the external medium or O2 evolution could be observed. The O2 evolution rates measured under red Light could be due to the assimilation of the CO2 derived from the HCO3 present in the medium. The blue Light-dependent O2 evolution rates were not diminished by a periplasmic carbonic anhydrase inhibitor, suggesting that HCO3 -dependent O2 evolution was due to the photoactivation of a selective HCO3 uptake system at the plasma membrane. The action spectrum for HCO3- uptake in M. braunii was very similar to those reported for NO3- and CI- suggested that a flavoprotein may be the photoreceptor for this response.

Nico C. Houter - One of the best experts on this subject based on the ideXlab platform.

  • gap effects on leaf traits of tropical rainforest trees differing in juvenile Light Requirement
    Oecologia, 2014
    Co-Authors: Nico C. Houter, Thijs L. Pons
    Abstract:

    The relationships of 16 leaf traits and their plasticity with the dependence of tree species on gaps for regeneration (gap association index; GAI) were examined in a Neotropical rainforest. Young saplings of 24 species with varying GAI were grown under a closed canopy, in a medium-sized and in a large gap, thus capturing the full range of plasticity with respect to canopy openness. Structural, biomechanical, chemical and photosynthetic traits were measured. At the chloroplast level, the chlorophyll a/b ratio and plasticity in this variable were not related to the GAI. However, plasticity in total carotenoids per unit chlorophyll was larger in shade-tolerant species. At the leaf level, leaf mass per unit area (LMA) decreased with the GAI under the closed canopy and in the medium gap, but did not significantly decrease with the GAI in the large gap. This was a reflection of the larger plasticity in LMA and leaf thickness of gap-dependent species. The well-known opposite trends in LMA for adaptation and acclimation to high irradiance in evergreen tropical trees were thus not invariably found. Although leaf strength was dependent on LMA and thickness, plasticity in this trait was not related to the GAI. Photosynthetic capacity expressed on each basis increased with the GAI, but the large plasticity in these traits was not clearly related to the GAI. Although gap-dependent species tended to have a greater plasticity overall, as evident from a principle component analysis, leaf traits of gap-dependent species are thus not invariably more phenotypically plastic.

  • Ontogenetic changes in leaf traits of tropical rainforest trees differing in juvenile Light Requirement
    Oecologia, 2012
    Co-Authors: Nico C. Houter, Thijs L. Pons
    Abstract:

    Relationships between leaf traits and the gap dependence for regeneration, and ontogenetic changes therein, were investigated in juvenile and adult tropical rainforest tree species. The juveniles of the 17 species included in the study were grown in high Light, similar to the exposed crowns of the adult trees. The traits were structural, biomechanical, chemical and photosynthetic. With increasing species gap dependence, leaf mass per area (LMA) decreased only sLightly in juveniles and remained constant in adults, whereas punch strength together with tissue density decreased, and photosynthetic capacity and chlorophyll increased. Contrary to what has been mostly found in evergreen tropical rainforest, the trade-off between investment in longevity and in productivity was evident at an essentially constant LMA. Of the traits pertaining to the chloroplast level, photosynthetic capacity per unit chlorophyll increased with gap dependence, but the chlorophyll a / b ratio showed no relationship. Adults had a twofold higher LMA, but leaf strength was on average only about 50% larger. Leaf tissue density, and chlorophyll and leaf N per area were also higher, whereas chlorophyll and leaf N per unit dry mass were lower. Ranking of the species, relationships between traits and with the gap dependence of the species were similar for juveniles and adults. However, the magnitudes of most ontogenetic changes were not clearly related to a species’ gap dependence. The adaptive value of the leaf traits for juveniles and adults is discussed.

  • ontogenetic changes in leaf traits of tropical rainforest trees differing in juvenile Light Requirement
    Oecologia, 2012
    Co-Authors: Nico C. Houter, Thijs L. Pons
    Abstract:

    Relationships between leaf traits and the gap dependence for regeneration, and ontogenetic changes therein, were investigated in juvenile and adult tropical rainforest tree species. The juveniles of the 17 species included in the study were grown in high Light, similar to the exposed crowns of the adult trees. The traits were structural, biomechanical, chemical and photosynthetic. With increasing species gap dependence, leaf mass per area (LMA) decreased only sLightly in juveniles and remained constant in adults, whereas punch strength together with tissue density decreased, and photosynthetic capacity and chlorophyll increased. Contrary to what has been mostly found in evergreen tropical rainforest, the trade-off between investment in longevity and in productivity was evident at an essentially constant LMA. Of the traits pertaining to the chloroplast level, photosynthetic capacity per unit chlorophyll increased with gap dependence, but the chlorophyll a/b ratio showed no relationship. Adults had a twofold higher LMA, but leaf strength was on average only about 50% larger. Leaf tissue density, and chlorophyll and leaf N per area were also higher, whereas chlorophyll and leaf N per unit dry mass were lower. Ranking of the species, relationships between traits and with the gap dependence of the species were similar for juveniles and adults. However, the magnitudes of most ontogenetic changes were not clearly related to a species’ gap dependence. The adaptive value of the leaf traits for juveniles and adults is discussed. Electronic supplementary material The online version of this article (doi:10.1007/s00442-011-2175-x) contains supplementary material, which is available to authorized users.

Aurora Galván - One of the best experts on this subject based on the ideXlab platform.

  • Blue‐Light Requirement for the biosynthesis of an NO2− transport system in the Chlamydomonas reinhardtii nitrate transport mutant S10*
    Plant Cell & Environment, 1999
    Co-Authors: Miguel Angel Quinones, Aurora Galván, Emilio Fernández, Pedro J Aparicio
    Abstract:

    The blue-Light Requirement for the biosynthesis of nitrite reductase and an NO2– transport system was studied in Chlamydomonas reinhardtii mutant S10. The only oxidized nitrogen species that could be taken up by this mutant was NO2–, due to the presence of NO2– transport systems and the absence of high-affinity NO3– transporters. NH4+-grown cells required illumination with blue Light to recover the ability to take up NO2– when resuspended in an NO2–-containing NH4+-deprived medium. This blue-Light- dependent recovery, which took 1 h, could be suppressed by cycloheximide, indicating that protein biosynthesis was involved. The biosynthesis of nitrite reductase took place in cell suspensions irradiated with red Light, even in the absence of NO2–, thus suggesting that the process requiring blue Light was the biosynthesis of an NO2– transport system. Nitrite reductase-containing cells (pre-irradiated with red Light) took 1 h to start consuming NO2– when they were additionally irradiated with blue Light in the presence of this anion, and this process was also cycloheximide-sensitive. The NO2– transport system operated either under red plus blue Light or red Light only. Thus, in C. reinhardtii mutant S10 cells, blue Light was only required for the biosynthesis of an NO2– transport system and not for its activity.

  • blue Light Requirement for the biosynthesis of an no2 transport system in the chlamydomonas reinhardtii nitrate transport mutant s10
    Plant Cell and Environment, 1999
    Co-Authors: Miguel Angel Quinones, Aurora Galván, Emilio Fernández, Pedro J Aparicio
    Abstract:

    The blue-Light Requirement for the biosynthesis of nitrite reductase and an NO2– transport system was studied in Chlamydomonas reinhardtii mutant S10. The only oxidized nitrogen species that could be taken up by this mutant was NO2–, due to the presence of NO2– transport systems and the absence of high-affinity NO3– transporters. NH4+-grown cells required illumination with blue Light to recover the ability to take up NO2– when resuspended in an NO2–-containing NH4+-deprived medium. This blue-Light- dependent recovery, which took 1 h, could be suppressed by cycloheximide, indicating that protein biosynthesis was involved. The biosynthesis of nitrite reductase took place in cell suspensions irradiated with red Light, even in the absence of NO2–, thus suggesting that the process requiring blue Light was the biosynthesis of an NO2– transport system. Nitrite reductase-containing cells (pre-irradiated with red Light) took 1 h to start consuming NO2– when they were additionally irradiated with blue Light in the presence of this anion, and this process was also cycloheximide-sensitive. The NO2– transport system operated either under red plus blue Light or red Light only. Thus, in C. reinhardtii mutant S10 cells, blue Light was only required for the biosynthesis of an NO2– transport system and not for its activity.