Dark Fixation of CO2 and Measurements of Organic Productivity. With Remarks on Chemo-Synthesis

1960 ◽  
Vol 13 (2) ◽  
pp. 348-357 ◽  
Author(s):  
E. Steemann Nielsen
Keyword(s):  
Dark Fixation ◽  
Organic Productivity

Transfer of photosynthetically fixed carbon between the prokaryotic green alga Prochloron and its ascidian host

1983 ◽  
Vol 34 (3) ◽  
pp. 431 ◽  
Author(s):  
DJ Griffiths ◽  
L Thinh
Keyword(s):  
Light Intensity ◽  
Green Alga ◽  
Host Tissue ◽  
Total Carbon ◽  
Symbiotic Association ◽  
Fixed Carbon ◽  
Low Light ◽  
Ascidian Species ◽  
Dark Fixation ◽  
Efficient Transfer

In the symbiotic association between the prokaryotic green alga Prochloron and three didemnid host species (Diplosoma similis, Lissoclinum bistratum, Trididemnum cyclops), between 6 and 51 % of the total carbon fixed during exposure for 1 h to H14CO3- in the light (150 �E m-2 s-1) becomes associated with the host tissue. Dark fixation of 14CO2 in these ascidian species and in Lissoclinum punctatum never exceeds 6% of photosynthetic fixation at saturating light intensity. The corresponding values for dark fixation of 14CO2 in isolated Prochloron cells fall within the same range. There is very little excretion of photosynthate from whole colonies of the above ascidian species nor from Didemnum molle, Lissoclinum voeltzkowi and Trididemnum miniatum (usually less than 1 % of total photosynthate at saturation light intensity), suggesting an efficient transfer mechanism from Prochloron to host. Evidence from pulse-chase experiments suggests that transfer probably involves the early products of photosynthesis. The extent of transfer of photosynthate between Prochloron and T. cyclops varies with the rate of photosynthetic 14CO2 fixation into the whole colony but there is some transfer even at low light intensities, which strongly limit photosynthesis.

scholarly journals Dark Fixation of CO2 in the Lake with Special Reference to Organic Matter Production

1970 ◽  
Vol 83 (990) ◽  
pp. 397-410 ◽  
Author(s):  
Masayuki TAKAHASHI ◽  
Yukuya YAMAGUCHI ◽  
Shun-ei ICHIMURA
Keyword(s):  
Organic Matter ◽  
Special Reference ◽  
Organic Matter Production ◽  
Matter Production ◽  
Dark Fixation

Calcification and organic productivity at the world's southernmost coral reef

2020 ◽  
Vol 227 ◽  
pp. 103870
Author(s):  
Kay L. Davis ◽  
Ashly McMahon ◽  
Rogger E. Correa ◽  
Isaac R. Santos
Keyword(s):  
Coral Reef ◽  
Organic Productivity

Phosphorus deficiency and phosphate uptake in the blue-green alga Anacystis nidulans

1968 ◽  
Vol 14 (4) ◽  
pp. 341-348 ◽  
Author(s):  
J. C. Batterton ◽  
C. Van Baalen
Keyword(s):  
Phosphorus Content ◽  
Phosphate Uptake ◽  
Phosphorus Deficiency ◽  
Normal Growth ◽  
Anacystis Nidulans ◽  
Anaerobic Conditions ◽  
Atp Formation ◽  
Transport Chain ◽  
Dark Fixation ◽  
Phosphate Incorporation

The normal level of phosphorus in Anacystis nidulans is approximately 3.7 μg Pi/mm3 cells. This value fell to 0.5 μg Pi/mm3 cells under prolonged starvation. Even at low cellular phosphate levels, cells were viable and continued to divide slowly. With cells containing approximately 1.5 μg Pi/mm3 cells a rapid dark uptake (15 minutes) of 0.8 μg Pi/mm3 cells was found. Data obtained in the rapid dark fixation suggest that approximately 25% of the total cellular phosphorus is possibly bound on specific sites. Light had little effect on this first phase of phosphate uptake. The subsequent uptake to the normal phosphorus content per cell and return to normal growth rate required light and nitrogen.Coincident with the rapid dark phosphate incorporation, synthesis of ATP began and continued, rising far above the level of normal cells. The rate of ATP formation was not influenced by light, but was blocked by anaerobic conditions or several classical inhibitors of the electron transport chain.

Effects of preillumination with light of different wavelengths on subsequent dark CO2-fixation in Chlorella cells

1970 ◽  
Vol 48 (6) ◽  
pp. 1203-1207 ◽  
Author(s):  
Shigetoh Miyachi ◽  
Daisuke Hogetsu
Keyword(s):  
Blue Light ◽  
Co2 Fixation ◽  
Red Light ◽  
Anaerobic Conditions ◽  
Nitrogen Gas ◽  
Pep Carboxylase ◽  
Radioactive Carbon ◽  
Initial Fixation ◽  
Dark Fixation ◽  
Dark Co2 Fixation

The effects of preillumination with monochromatic red or blue light on the subsequent dark 14CO2-fixation in Chlorella cells were studied under aerobic as well as anaerobic conditions. When the cell suspension was made aerobic by bubbling air (CO2-free) throughout the periods of preillumination and the following dark 14CO2-fixation, the initial fixation product was mainly PGA. The radioactive carbon first incorporated in PGA was transferred mostly to aspartate during the later periods of dark 14CO2-fixation. The rate of 14C-incorporation into aspartate after preillumination with blue light was 2 to 3 times as high as that observed after red-light pretreatment. The observations support our previous inference that the activity of PEP carboxylase in Chlorella cells is stimulated by preillumination with blue light. When nitrogen gas was used during preillumination and the subsequent dark fixation, the radioactivity of 14C incorporated during the initial enhanced 14CO2-fixation was eventually transferred to alanine and lactate. The increase in radioactivity of alanine and lactate was more pronounced during dark fixation after preillumination with red light than after preillumination with blue light.

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