Nodularia Harveyana Research Articles

Cadmium adsorption by the non-living biomass of microalgae grown in axenic mass culture

The freeze-dried (extracted and non-extracted) biomass of 15 microalgal species grown in axenic mass culture and belonging to the Cyanobacteria, Chloro-, Eustigmato-, Phaeo-, Rhodo- and Tribophyceae were investigated for their ability to adsorb cadmium (Cd) ions from aqueous solutions. For comparison, other standard adsorbing materials (activated carbon, silica gel, siliceous earth) were included in the studies. The biomass of 11 microalgae exhibited a higher Cd adsorption than the standard materials. Extraction of the algal biomass increased the Cd adsorption capability of some, but not all microalgae. High Cd adsorption was found inAnabaena lutea, Nodularia harveyana, andNostoc commune (Cyanobacteria),Chlamydomonas sp. (Chlorophyceae),Bumilleriopsis filiformis (Tribophyceae), and inEctocarpus siliculosus, Halopteris scoparia andSpermatochnus paradoxus (Phaeophyceae). The specific surface (m2 cm−3) of the various microalgae was determined by means of laser diffractometry.Anabaena inaequalis andA. lutea (Cyanobacteria) and the Phaeophyceae had especially high Cd adsorption per surface unit. Most of the Cd adsorbed to these various materials could be desorbed subsequently with diluted mineral acid (pH 2).

Structure of the “heterocyst glycolipids” of the marine cyanobacterium Nodularia harveyana

The “heterocyst glycolipids” have been reported to take part in the protection of the specialized cyanobacterial cells capable of N 2 fixation against the penetration of O 2. For the first time such glycolipids have been isolated in a pure form from a cyanobacterium, Nodularia harveyana , and their structures have been established by spectroscopic and chemical means to be 1-(O-α-D-glucopyranosyl)-3R,25R-hexacosanediol, 1-(O-α-D-glucopyranosyl)-3S,25R-hexacosanediol and 1-(O-α-D-glucopyranosyl)-3-keto-25R-hexacosanol.

On the structure, cell differentiation and life cycle of blue-green alga Nodularia harveyana (THWAITES) Thuret:

On the structure, cell differentiation and life cycle of blue-green alga Nodularia harveyana (THWAITES) Thuret:

Osmotic Adjustment of Cyanobacteria: The Effects of NaCl, KCl, Sucrose and Glycine Betaine on Glutamine Synthetase Activity in a Marine and a Halotolerant Strain

The effects of NaCl, KCl and the organic osmotica sucrose or glycine betaine on glutamine synthetase (GS) transferase activity in crude extracts of the marine Nodularia harveyana and the halotolerant Synechocystis sp. DUN52, respectively, were examined. NaCl at low concentrations (≤ 0.75 M) stimulated the enzyme (up to 30%) in the halotolerant strain but was inhibitory above 0.2 M in the marine strain. In both strains KCl (0.1-1.3 M) stimulated GS activity and was inhibitory only above 1.4 M. Sucrose, the major intracellular organic osmoticum in N. harveyana, had only a slight inhibitory effect until concentrations above 0.3 M; 2.0 M sucrose caused a 60% inhibition. The quaternary ammonium compound glycine betaine, the primary organic osmoticum in Synechocystis sp. DUN52, was not inhibitory at physiologically relevant concentrations up to 1.8-2.0 M and reduced NaCl inhibition by 10-30% at NaCl concentrations from 0.8 to 2.0 M in the halotolerant strain when used at 1.0 M. At NaCl concentrations above 0.2 M, 0.2 M KCl reduced the activity of GS by 6-15%. Sucrose and KCl showed similar degrees of protection against NaCl inhibition in N. harveyana when used at concentrations similar to those measured in seawater-grown cells of N. harveyana. Increasing concentrations of glycine betaine increased protection of GS activity against NaCl inhibition at NaCl concentrations above 0.5 M. These results suggest that the extent of salt tolerance of a particular strain of cyanobacterium may depend, in part at least, on the metabolic effects of compounds that are accumulated as internal osmotica in that strain.