DARK FIXATION OF C14-BICARBONATE BY MARINE ALGAE

1963 ◽  
Vol 41 (3) ◽  
pp. 317-325 ◽  
Author(s):  
J. S. Craigie

The ability of several multicellular marine algae to remove NaHC14O3 from seawater in darkness has been compared. Members of the Phaeophyta removed approximately four to eight times more isotope than did members of the Rhodophyta and Chlorophyta examined. After 2 minutes of dark fixation, aspartic and glutamic acids were the main compounds identified in both Fucus vesiculosus and Polysiphonia lanosa. Radioactivity appeared largely in citric plus isocitric acids in Fucus, whereas radioactive organic acids were not detected in Polysiphonia even after 30 minutes. Fractionation of F. vesiculosus after 2 hours of dark fixation showed that 95% of the total radioactivity recovered occurred in the fraction soluble in 70% acetone.Twenty-four hours of darkness immediately prior to a 2-hour dark fixation period reduced the total radioactivity incorporated to almost one-half of the control values. Either artificial seawater (one-fifth natural salinity) or a medium in which NaCl was substituted by KCl had little effect on the total radioactivity fixed during darkness. The distribution of isotope, however, showed some alterations.

1963 ◽  
Vol 41 (1) ◽  
pp. 155-163 ◽  
Author(s):  
R. G. S. Bldwell ◽  
N. R. Ghosh

Fronds of F. vesiculosus were supplied with glucose-UL-C14, pyruvate-2-C14, acetate-1-C14, acetate-2-C14, or formate-C14, the acids being presented as the sodium salts. The radioactivity of various fractions of the fronds as well as respired CO2 was determined after various times, and the distribution of radioactivity among the compounds present in the alcohol extract was determined. The contribution of glucose to respired CO2 was much less than that of the organic acids. However, although its uptake and metabolism were less, a large proportion of the glucose that was metabolized was converted to CO2. Glucose contributed somewhat to polysaccharides, but the organic acids were much better precursors of alginic acid. The pattern of labelling among soluble compounds, of which glycerol was especially prominent, indicated that several pathways of metabolism operated, involving both carboxylation and decarboxylation reactions.


1964 ◽  
Vol 42 (1) ◽  
pp. 23-33 ◽  
Author(s):  
J. S. Craigie ◽  
J. McLachlan

Normal, healthy thalli of Fucus vesiculosus have been shown to release into the surrounding medium yellow compounds which absorb ultraviolet light. A study of this phenomenon revealed that brief exposure to elevated temperatures (20 °C) increased the amount of pigment released. There was no difference in the production in light or darkness and only a small decrease with reduced salinity. The amount of pigmentation observed in the medium was directly proportional to the degree of alkalinity from pH 7 to pH 9.A number of other macrophytes and microphytes were examined and only those possessing physodes released substances giving a spectrum similar to that of F. vesiculosus.Isolation of the material, alkaline hydrolysis, and chromatography revealed phloroglucinol and several unidentified fluorescent substances. It appears that these materials were flavonols or catechin-type tannins.


1967 ◽  
Vol 45 (9) ◽  
pp. 1557-1565 ◽  
Author(s):  
R. G. S. Bidwell

Samples of Fucus vesiculcsus fronds were permitted to assimilate 14CO2 for 5 h and were then maintained in alternating periods of light and darkness for 3 days. Samples were collected at intervals, and the radioactivity of various simple and complex compounds was measured. The major product of photosynthesis was mannitol; relatively small amounts of 14C entered other compounds. From its behavior, it appears that mannitol is the major substrate of respiration in these plants; there may be secondary substrates among the complex polysaccharides. The complex polysaccharides are not formed directly from mannitol in light, but from some common precursors, or else from a small isolated pool of mannitol which is separated from the main cellular supplies. In darkness, the complex polysaccharides appear to be derived from stored mannitol. One of the more active metabolites, judged from its behavior, is a component of the residue left after dilute acid and sodium carbonate extraction. This component undergoes turnover, i.e. breakdown and resynthesis from newly-acquired photosynthate in the light, and is formed from stored photosynthate in the darkness.


1972 ◽  
Vol 50 (1) ◽  
pp. 191-197 ◽  
Author(s):  
R. G. S. Bidwell ◽  
Elizabeth Percival ◽  
Berit Smestad

Samples of Fucus vesiculosus fronds were allowed to assimilate 14CO2 for 10 min and 3 h. In a second experiment fronds were allowed to grow for 10 min in 14CO2 and were then transferred to fresh medium containing 12CO2. Samples were taken immediately, after 30 min, and after 2 h. Sequential extraction and fractionation of the polysaccharides from each of the five samples gave 14C-labeled laminaran, xylogalactofucoglucuronan (A), xyloglucuronogalactofucan (B) (these polysaccharides are named in the order of the increasing proportions of their constituent sugars), fucoidan (C), alginic acid, and residual polysaccharide material containing mainly glucose with some galactose. The activities of each of the polysaccharides, the residual material, and their constituent sugars were measured. Highly active low molecular weight carbohydrates, present in the acid extract, are the suggested precursors of the polysaccharides. The fucose-containing polysaccharides represent the extremes of a family of polymers; it is postulated from these studies that (A) is transformed into fucoidan via polysaccharide (B) in this alga.


1962 ◽  
Vol 40 (6) ◽  
pp. 803-807 ◽  
Author(s):  
R. G. S. Bidwell ◽  
N. R. Ghosh

C14-mannitol was supplied to fronds of F. vesiculosus, and its conversion into CO2 and other compounds was studied. Only small amounts of the mannitol taken in were metabolized. Mannitol is apparently not an immediate substrate of respiration, but in time it may be converted into some other substances which are. Dilute acid-soluble polysaccharides acquired small amounts of radioactivity, but most of the mannitol which underwent metabolism was eventually converted to residual carbohydrates. It is concluded that mannitol is probably a storage compound rather than an active metabolite.


2018 ◽  
Vol 10 ◽  
pp. 01007
Author(s):  
Ewa Jachniak ◽  
Joanna Chmura ◽  
Mariusz Kuglarz ◽  
Józef Wiktor

The aim of the research was to try to obtain of the biogas on a laboratory scale from marine algae biomass and water plant biomass. The research was conducted in 2016 year and samples were taken from the Polish coast of the Baltic Sea. In laboratory work, algae and plant species were first identified. The next, in order to subject them to methane fermentation processes and to obtain biogas,partial mechanical treatment of the biomass was conducted. Dry matter content and dry organic matter content were also determined. The research has shown different production of the biogas depending on the various species of the algae and plants. The percentage composition of the biogas was also determined (% CO2 and % CH4). In this research some kinds and species of algae and aquatic plants were distinguished: Scytosiphon cf. S. tortilis, Fucus vesiculosus, Cladophora, Audouinella, Potamogeton perfoliatus. Production of biogas from selected algae and water plants oscillated between 0.023 dm3·g-1 and 0.303 dm3·g-1. The highest content of the methane in biogas was obtained from the mixture of Ectocarpus from spring and autumn harvest (values oscillated from 80.7 % to 81.2 %), while the highest percentage share of carbon dioxide in the biogas was characterized by the mixture Fucus vesiculosus and Audouinella (22 %). Due to a small amount of the research in this field, more research is needed.


1972 ◽  
Vol 15 (3) ◽  
Author(s):  
HISAYOSHI AKAGAWA ◽  
TOMOYOSHI IKAWA ◽  
KAZUTOSI NISIZAWA

1965 ◽  
Vol 43 (2) ◽  
pp. 281-285 ◽  
Author(s):  
Kenneth L. Webb ◽  
J. W. A. Burley

After dark fixation of C14O2 by salt marsh obligate halophytes, most of the 80% ethanol-soluble label appeared in the amino acid fraction. Species tested were Batis maritima L., Salicornia europaea L., Salicornia virginica L., and Borrichia frutescens (L.) D.C.A time study was made of the dark fixation products of C14O2 by Spartina alterniflora Loisel, a facultative halophyte, cultured with and without NaCl in the nutrient medium. In this species the greater proportion of label was recovered from amino acids (principally aspartic and glutamic acids) at times of 1 hour and less, the pattern changing to favor organic acids at longer times, mainly malic acid in NaCl-free plants. The shift to organic acids was slower in plus NaCl plants with aconitic and an unidentified acid appearing along with malic as the principal labelled acids.NaCl reduced the rate of C14O2 assimilation by Spartina alterniflora. Initially, the fixation pattern resembled that of obligate halophytes, becoming more like that of terrestial plants (glycophytes) after 1 hour.


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