Showing papers on "Chlorococcum published in 1991"
TL;DR: Cell volumes and intracellular concentrations of major solutes of Chlorococcum submarinum were determined before and after salinity shocks and these results are consistent with a decrease in efficiency of PS2.
Abstract: Cell volumes and intracellular concentrations of major solutes of Chlorococcum submarinum were determined before and after salinity shocks. Cells were found to shrink in size by about 30% following changes from 0.1 to 0.5 M NaCl, there was a transitory increase in sodium concentration and more permanent increases in concentrations of potassium, proline and glycerol (the major osmolyte). Conversely, cells doubled in size after the reciprocal downshock, there was rapid loss of about 70% of the cells' glycerol to the medium, a much smaller loss of cellular potassium and a steady disappearance of proline from the cells. The respiratory and photosynthetic responses to salinity fluctuations were also studied. Salinity downshocks stimulated respiration by 30% and inhibited photosynthesis by 16% within 5 min, but within 2 h these rates were identical to control rates. Upshocks caused a slight inhibition of respiration, but decreased photosynthesis by 40% within 5 min and recovery took 2 h. Downshocks had little effect on chlorophyll fluorescence, however, Fo strongly increased and both Fm and Fv/Fm declined within 5 min of salinity increases. This is consistent with a decrease in efficiency of PS2. Ecological and metabolic implications of the results are discussed.
22 citations
TL;DR: Chlorococcum submarinum, isolated from a tidal rockpool, was shown to be highly resistant to environmental stress, and has an extraordinarily wide pH tolerance.
Abstract: Chlorococcum submarinum, isolated from a tidal rockpool, was shown to be highly resistant to environmental stress. The alga can grow in salinities from a few mmol m-3 to 2 kmol m-3, with optimum growth occurring between 0·1 and 0·5 kmol m-3. It has an extraordinarily wide pH tolerance, growing from pH 2 to at least 10·5. C. submarinum is also resistant to copper, growing (at 10–15% of optimum rates) in the presence of 10 ppm copper.
13 citations
TL;DR: A unicellular green alga recently isolated from a Yorkshire (UK) tidal rockpool is shown to be a species of Chlorcoccum, very similar to the previously characterized species C. submarinum.
Abstract: A unicellular green alga recently isolated from a Yorkshire (UK) tidal rockpool is shown to be a species of Chlorcoccum, very similar to the previously characterized species C. submarinum. Although the original description of C. submarinum is incomplete and does not meet current taxonomic specifications, we nevertheless consider our isolate conspecific with it. Our isolate can be differentiated from all other currently recognized species of Chlorococcum. A full description of C. submarinum is given, with comments on the use of standard techniques in taxonomic assessments.
8 citations
TL;DR: The results showed that glycerol was the major internal solute and that the total measured solutes balanced the external osmotic pressure at all three salinities.
Abstract: A method is described for measuring the cell volume of the unicellular green alga Chlorococcum submarinum, which depends on measurements of bromide concentration before and after disruption of the cells by ammonium hydroxide. Simultaneous equations are derived, which along with direct determination of cell water weight, allow the calculation of the intracellular volume in three different ways. The volumes calculated are in agreement indicating the validity of the method. The cell volumes and internal concentrations of glycerol, proline, potassium and sodium were determined for algae adapted to three salinities, 0.1, 0.5 and 1.0 M NaCl. The results showed that glycerol was the major internal solute and that the total measured solutes balanced the external osmotic pressure at all three salinities.
5 citations
Journal Article•
TL;DR: The result suggests that some kinds of bacteria, algae and mixed cultural microorganisms could be good food sources for the growth of copepoda.
Abstract: Microbial organisms including yeast, Acinetobacter sp. AG-3, Chlorococcum sp., Chlorella sp. and some of their combinations were tested to evaluate growth efficiency of Tigriopus japonicus. Body length and weight of the copepoda were measured during four days experiment. Acinetobacter sp. AG-3, dried yeast(produced Wago), Chlorella sp., Chlorococcum sp. and mixed culture were used as food sources. Yeast(Y.) was the most effective food for the growth during nauplius stage and efficiencies of bacteria(Bact.)+chlorococcum sp.(RA), Chlorococcum sp.(RA), Bact.+chlorella sp.(Ch.), Bact. and Ch. decreased in odor, while for the growth of copepodite and adult, Bact.+RA was the most effective food with decreased efficiency of Y., RA, Bact. + Ch., Bact., Ch. in order. The ratio of weight gain to the food uptaken, after the weight and food units were converted to carbon, was between 21.6 and , This result suggests that some kinds of bacteria, algae and mixed cultural microorganisms could be good food sources for the growth of copepoda.
2 citations