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  • Wiley-Blackwell  (41)
  • Blackwell Publishing Ltd  (29)
  • American Physical Society  (26)
  • American Association for the Advancement of Science (AAAS)  (22)
  • 1
    Electronic Resource
    Electronic Resource
    GEOCHEMICAL CHARACTERIZATION OF STREAMBED SEDIMENT IN THE UPPER ILLINOIS RWER BASIN (1992)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Water Resources Association 28 (1992), S. 0 
    Details
    ISSN: 1752-1688
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: : Geochemistry of fine-fraction streambed sediments collected from the upper illinois River basin was surveyed in the fall of 1987 as part of the U.S. Geological Survey National Water-Quality Assessment pilot projects. The survey included 567 samples analyzed for 46 elements. Three distinctive distribution patterns were found for seven U.S. Environmental Protection Agency priority pollutants surveyed, as well as for boron and phosphorus: (1) enrichment of elements in the Chicago urban area and in streams draining the urban area relative to rural areas, (2) enrichment in main stems relative to tributaries, and (3) enrichment in low-order streams at high-population-density sites relative to low-population-density sites. Significant differences in background concentrations, as measured by samples from low-order streams, were observed among five subbasins in the study area. Uncertain geochemical correspondence between low-order, background sites and high-order, generally metal enriched sites prevented determination of background levels that would be appropriate for high-order sites. The within-sample ratio of enriched elements was variable within the Chicago area but was constant in the Illinois River downstream from Chicago. Element ratios imply a composite fine-fraction sediment in the Illinois River of 35–40 percent Des Plaines River origin and 60–65 percent Kankakee River origin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1752-1688.1992.tb03193.x
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  • 2
    Electronic Resource
    Electronic Resource
    Significance of the Regulation of Plasma Kallikrein by α2M (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 737 (1994), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1994.tb44323.x
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  • 3
    Electronic Resource
    Electronic Resource
    The effects of pH and dissolved inorganic carbon on external carbonic anhydrase activity in Chlorella saccharophila (1996)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 19 (1996), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: External carbonic anhydrase (CA) activity in Chlorella saccharophila is suppressed by growth at high dissolved inorganic carbon and at acid pH. External CA activity was shown to be suppressed by growth at pHs below 7.0, with total repression at pH5.0. Growth in the presence of the buffer 3-[N-Morpholino]propane-sulphonic acid (MOPS) between pH 7 and 8 suppressed CA activity. Cells grown at pH8.0 aerated at 6 dm3 h−1 exhibited external CA activity of 5 units mg−1 Chl once the dissolved inorganic carbon (DIC) was reduced to 300 mmol m−3, and this increased to 30 units mg−1 Chl over a period of 3d while the DIC dropped to 30mmol m−3. Cells aerated at 180 dm3 h−1 showed a similar trend in CA activity, although the onset was delayed by 1 d and the DIC did not drop below 300 mmol m−3. Cells grown at pH 7.8 near an air equilibrium DIC of 300 mmol m−3had no detectable external CA activity. It is probable that it is the CO2 supply to the cell, and not total DIC or HCO−3 which controls external CA activity. Cells grown at pH 5.0 had no detectable activity, although they reduced the CO2 concentration to 0.6 mmol m−3. The loss of CA upon transfer of air-grown cells to 10 mmol mol−1 CO2 took place over 48 h and was light dependent, while the loss upon transfer from alkaline pH to acid pH look place over 12 h and was independent of light. The effects of pH are independent of the response to CO2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3040.1996.tb00341.x
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  • 4
    Electronic Resource
    Electronic Resource
    Measurement of the photorespiratory activity of the submerged aquatic plant Myriophyllum spicatum L. (1989)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 12 (1989), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract The CO2 compensation concentrations (points) of leaves of the submerged vascular aquatic plant Myriophyllum spicatum L. were determined in a closed aqueous system at pH 7.0 by a gas chromatographic technique and over the range 10–30deg;C were found to range from 36 to 46 cm3m−3 in medium equilibrated with 21% O2 (0.03 kgm−3), and 25 to 35 cm3m−3 in medium equilibrated with 2% O2 (0.03 kgm−3). The rates of true (TPS) and apparent (APS) photosynthesis of leaves were measured in medium equilibrated with 21% O2 and buffered at pH 7.0, at subsaturating concentrations (12.8–18.8 mmol m−3) of dissolved inorganic carbor. (DIC) containing H14CO3, by determining the initial rates of uptake by the leaves of DIC and 14C-activity from the medium. The rate of photorespiration, the difference between TPS and APS, was 7.0–13.3% of TPS over the range of 10–25°C and rose to 29% of TPS at 35°C. The magnitude of the compensation point of this plant is therefore similar to, but is much less O2-sensitive than, those of C3 plants, and the photorespiratory rate, at DIC concentrations near the CO2 compensation point, is very low compared to that of C3 plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3040.1989.tb01642.x
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  • 5
    Electronic Resource
    Electronic Resource
    CO2 uptake and transport in leaf mesophyll cells (1985)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 8 (1985), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract The acquisition of inorganic carbon for photosynthetic assimilation by leaf mesophyll cells and chloroplasts is discussed with particular reference to membrane permeation of CO2 and HCO−3. Experimental evidence indicates that at the apoplast pH normally experienced by leaf mesophyll cells (pH 6–7) CO2 is the principal species of inorganic carbon taken up. Uptake of HCO−3 may also occur under certain circumstances (i.e. pH 8.5), but its contribution to the net flux of inorganic carbon is small and HCO−3 uptake does not function as a CO2-concentrating mechanism. Similarly, CO2 rather than HCO−3 appears to be the species of inorganic carbon which permeates the chloroplast envelope. In contrast to many C3 aquatic plants and C4 plants, C3 terrestrial plants lack specialized mechanisms for the acquisition and transport of inorganic carbon from the intercellular environment to the site of photosynthetic carboxylation, but rely upon the diffusive uptake of CO2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3040.1985.tb01680.x
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  • 6
    Electronic Resource
    Electronic Resource
    Photosynthetic carbon assimilation in the blue-green alga Coccochloris peniocystis (1981)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 4 (1981), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract. Cells of the blue-green alga Coccochloris peniocystis, grown at air levels of CO2, were exposed to [l4C]bicarbonate in the light for periods of 0.5 to 2.0 s followed by exposure to unlabelled bicarbonate for longer periods of time in the light. The kinetics of tracer movement during these pulse-chase experiments demonstrate that the principal mechanism of CO2 fixation in this alga is the C3-pathway although an appreciable amount of the C4 acid aspartate is found as one of the initial products of photosynthesis. Degradation of the labelled aspartate revealed that after 20 s of illumination, over 95% of the radioactivity was located in the β-carboxyl of this C4 acid. This alga possesses little, if any, capacity for either the enzymatic decarboxylation of C4 acids or the regeneration of phosphoenolpyruvate (PEP) from pyruvate mediated by the enzyme pyruvate, Pi dikinase. These data further demonstrate the lack of a functional C4-pathway in this alga.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/1365-3040.ep11604546
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  • 7
    Electronic Resource
    Electronic Resource
    The active uptake of carbon dioxide by the unicellular green algae Chlorella saccharophila and C. ellipsoidea (1991)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 14 (1991), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract. Mass spectrometry has been used to measure the rates of CO2 uptake of acid- and alkali-grown cells of the green algae Chlorella ellipsoidea (UTEX 20) and C. saccharophila (UTEX 27). The time course of CO2 formation on addition of 100mmol m−3 K2CO3 to cells in the dark was used as an assay for external carbonic anhydrase (CA). No external CA was detected in acid-grown cells of either species or in alkali-grown cells of C. ellipsoidea but was present in alkali-grown C. saccharophila. In the absence of external CA, or when it was inhibited by 5mmol m−3 acetazolamide, cells of both species, on illumination, rapidly depleted the free CO2 in the medium at pH 7.5 to near zero concentrations before maximum photosynthetic O2 evolution rates were established. Addition of bovine CA rapidly restored the equilibrium CO2 concentration in the medium, indicating that the cells were selectively taking up CO2. Transfer of cells to the dark caused a rapid increase in the CO2 concentration in the medium largely due to the efflux of inorganic carbon from the cells as CO2. This rapid light-dependent CO2 uptake takes place against pH and concentration gradients and, thus, has the characteristics of active transport.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3040.1991.tb00945.x
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  • 8
    Electronic Resource
    Electronic Resource
    The effect of temperature and oxygen on the CO2 compensation point of the marine alga Ulva lactuca (1984)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 7 (1984), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract The CO2 compensation point of Ulva lactuca frond sections has been measured in artificial seawater using a sensitive gas-chromatographic method. Under nitrogen the compensation point remained relatively constant at 3–6 cm3 m−3 at temperatures from 10 to 30°C while in air-saturated medium (0.3 kg m−3 O2) the compensation point rose from 5 cm3 m−3 at 10°C to 11 cm3 m−3 at 30°C. These responses of the compensation point to temperature and oxygen concentration indicate that there is little photorespiratory CO2 loss in this marine macroalga, and the low values of these compensation points indicate that inorganic carbon is actively accumulated by the plant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/1365-3040.ep11592150
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  • 9
    Electronic Resource
    Electronic Resource
    The active uptake of carbon dioxide by the marine diatoms Phaeodactylum ticornutum and Cyclotella sp. (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 18 (1995), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Mass spectromelry has been used to investigate the uptake of CO2 by two marine diatoms, Phaeodactylum tricornutum and Cyclotella sp. The time course of CO2 formation in the dark after addition of 100 mmol m−3 dissolved inorganic carbon (DIC) to cell suspensions showed that external carbonic anhydrase (CA) was not present in cells of P. tricornutum but was present in Cyclotella sp. In the absence of external CA, or when it was inhibited by 5 mmol m−3 acetazolamide, cells of both species preincubated with 100 mmol m−3 DIG rapidly depleted almost all of the free CO2 (3·2mmol m−31 at pH7·5) from the suspending medium within seconds of illumination and prior to the onset of steady-state photosynthesis. Addition of bovine CA quickly restored the HCO3−–CO2 equilibrium in the medium, indicating that the initial depletion of CO2 resulted from the selective uptake of CO2 rather than uptake of all DIG species. Transfer of cells to the dark caused a rapid increase in the CO2 concentration in the medium, largely as a result of the efflux of unfixed inorganic carbon from the cells. The measured CO2 uptake rates for both species accounted for 50% of the total DIG uptake at HCO3−–CO2 equilibrium, indicating that HCOHCO3− was also being taken up. These results indicate that both Phaeodactylum tricornutum and Cyclotella sp. have the capacity to transport CO2 actively against concentration and pH gradients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3040.1995.tb00600.x
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  • 10
    Electronic Resource
    Electronic Resource
    Photosynthetic inorganic carbon uptake and accumulation in two marine diatoms (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 18 (1995), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Some physiological characteristics of photosynthetic inorganic carbon uptake have been examined in the marine diatoms Phaeodactylum tricornutum and Cyclotella sp. Both species demonstrated a high affinity for inorganic carbon in photosynthesis at pH7.5, having K1/2(CO2) in the range 1.0 to 4.0mmol m−3 and O2− and temperature-insensitive CO2 compensation concentrations in the range 10.8 to 17.6 cm3 m−3. Intracellular accumulation of inorganic carbon was found to occur in the light; at an external pH of 7.5 the concentration in P. tricornutum was twice, and that in Cyclotella 3.5 times, the concentration in the suspending medium. Carbonic anhydrase (CA) was detected in intact Cyclotella cells but not in P. tricornutum, although internal CA was detected in both species. The rates of photosynthesis at pH 8.0 of P. tricornutum cells and Cyclotella cells treated with 0.1 mol m−3 acetazolamide, a CA inhibitor, were 1.5- to 5-fold the rate of CO2 supply, indicating that both species have the capacity to take up HCO3− as a source of substrate for photosynthesis. No Na+ dependence for HCO3− could be detected in either species. These results indicate that these two marine diatoms have the capacity to accumulate inorganic carbon in the light as a consequence, in part, of the active uptake of bicarbonate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3040.1995.tb00601.x
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