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  • 1
    Electronic Resource
    Electronic Resource
    The kinetics of photoinhibition and its recovery in the red alga Porphyridium cruentum (1988)
    Springer
    Archives of microbiology 150 (1988), S. 529-533 
    Details
    ISSN: 1432-072X
    Keywords: Photosynthesis ; O2 evolution ; Photoinhibition ; Recovery ; Porphyridium cruentum ; Biomass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract When Porphyridium cruentum cells were illuminated with high fluence rate between 1900 and 4800 μmol photons m-2s-1, a decrease in the photosynthetic activity of the cells was observed. Within the time frame of 20 min, and under the fluence rates studied, the sum of photons to be absorbed by cells (mg of chlorophyll (Chl), sufficient to initiate photoinhibition was calculated to be 9235.8 μmol. The minimal specific light absorption rate to initiate photoinhibition in P. cruentum ranges between 2.29 and 4.26 μmol photons s-1 mg-1 chl.a. There was a linear relationship between the specific rate of photoinhibition and the specific light absorption rate. A photon number of 2.56×104 μmol mg-1 chl.a photoinhibited photosynthesis instantaneously. At 15°C, no photoinhibitory effect was observed at 2300 μmol photons m-2 s-1 even after 45 min of illumination. At the other extreme of 35°C, 84% inhibition of photosynthetic activity was observed within 10 min of exposure to 2300 μmol photons m-2 s-1. Between 20 and 30°C, the photoinhibitory effect was comparable. Photoinhibited P. cruentum cells recovered readily when transferred to low light (90 μmol photons m-2 s-1) and darkness, and the specific rate of recovery was independent of the light intensity to which the cells were exposed, during the photoinhibitory treatment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00408244
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  • 2
    Electronic Resource
    Electronic Resource
    Determination of biomass dry weight of marine microalgae (1997)
    Springer
    Journal of applied phycology 9 (1997), S. 189-194 
    Details
    ISSN: 1573-5176
    Keywords: biomass dry weight ; washing methods ; ammonium bicarbonate ; Dunaliella sp. ; Isochrysis galbana ; Nannochloropsis sp. ; Nitzschia closterium ; Porphyridium cruentum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Total biomass dry weight (DW) and ash free dry weight (AFDW) of five species of marine microalgae, Dunaliella sp., Isochrysis galbana, Nannochloropsis sp., Nitzschiaclosterium and Porphyridium cruentum, retained on filter paper, were determined. Dunaliella and Isochrysis cells have no cell wall; Nannochloropsis, Nitzschia and Porphyridium possess a cell wall and Nitzschia and Porphyridium cells are covered by silica and mucilage coating, respectively. In all these algae, DW of non-washed samples was at least 1.2 times higher than those washed by distilled water,0.9% sodium chloride, 0.5 M ammonium formate or 0.5 M ammonium bicarbonate. DW of 0.9% sodium chloride washed samples was more than 0.8 times higher than the other three washed samples. In most of the cases, there was no significant difference between DW of samples washed by ammonium formate and ammonium bicarbonate solutions (p〉0.05). The AFDW of the non-washed algal samples was about twice that washed samples, and could be accounted for by volatile component in the sea water medium. Isotonic solution of ammonium bicarbonate is a satisfactory washing agent for algal cells for dry weight determination.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007914806640
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  • 3
    Electronic Resource
    Electronic Resource
    Effect of triethylamine in the mobile phase on the retention properties of conventional polymeric and horizontally polymerized octadecylsilica in RPLC (1999)
    Springer
    Chromatographia 49 (1999), S. 635-642 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Interaction of mobile and stationary phases ; Linear solvation energy relationships ; Triethylamine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The effect of triethylamine (TEA) in the mobile phase on the RPLC retention behavior of small organic solutes has been studied on a conventional polymeric octadecylsilica (ODS) and on a horizontally polymerized ODS. Retention factors for a set of solutes were measured on the two phases with methanol-water mobile phases containing triethylamine at different concentrations and analyzed by use of linear solvation energy relationships (LSER). Variation of the resulting LSER coefficients—v (hydrophobicity),r (polarizability),s (dipolarity),b (hydrogen-bond (HB) donating acidity), anda (HB accepting strength)—were examined to see how TEA affects the intermolecular interaction properties of the mobile and stationary phases and hence the retention of the solutes. Addition of TEA to the mobile phase changes the interaction properties of both conventionally polymerized and horizontally polymerized ODS; the effect is greater for the conventional phase. The HB donating acidity (b) of conventional polymeric ODS is significantly reduced by addition of TEA. For the mobile phases studied the magnitudes of theb andv coefficients for the horizontally polymerized ODS phase are greater than for the conventional phase. The different interaction properties of the two polymeric phases arise mainly as a result of differential adsorption of TEA, because of the very different amounts of surface silanol groups present on the two phases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02466905
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    Paper (German National Licenses)
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