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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
    Effects of temperature and growth phase on lipid and biochemical composition of Isochrysis galbana TK1 (1997)
    Springer
    Journal of applied phycology 9 (1997), S. 451-457 
    Details
    ISSN: 1573-5176
    Keywords: Isochrysis galbana ; lipid ; biochemical composition ; fatty acid ; temperature ; growthphase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The lipid and biochemical composition of the haptophyte Isochrysis galbana TK1 was examined. Cultures were grown at 15 °C and 30 °C, and harvested in the exponential and early stationary growth phases. Carbohydrate and protein content varied at the two culture temperatures and growth phases. The highest protein content was found at the exponential growth phase at 15 °C, and the highest carbohydrate content was found at the stationary phase at the same culture temperature. Lipid accumulated in the stationary growth phase and its content was higher at 30 °C than at 15 °C regardless of the growth phase. The neutral lipids were the major class of lipid found in all the cultures. The stationary phase culture had a higher proportion of neutral lipids than the exponential phase culture and the proportion decreased slightly when culture temperature was increased from 15 °C to 30 °C. Phospholipid levels remained constant at the two temperatures, but slightly decreased in the stationary phase. Glycolipids in the exponentially growing cells were higher than those from stationary growth phase and increased with temperature. Polyunsaturated fatty acids (PUFAs) predominated in glycolipids and phospholipids. Cells grown at 15 °C contained higher proportion of 18:3 (n–3) and 22:6 (n–3) with a corresponding decrease in 18:2 (n–6), monounsaturated and saturated fatty acids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007973319348
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  • 3
    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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    Paper (German National Licenses)
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