Blue-green Alga Anabaena Flos-aquae Research Articles

Growth Rates and Digestive Abilities of Bullfrog Tadpoles (Rana catesbeiana) Fed Algal Diets

Although there are many accounts of the diversity of algae consumed by anuran larvae, growth and digestive responses of tadpoles fed algae have been poorly studied. In this study, growth rates and digestive abilities of larval bullfrogs (Rana catesbeiana) fed monospecific algal diets were investigated. The four algal species used in feeding trials were Selenastrum capricornutum, Microcystis incerta, Anabaena flos-aquae, and Ulothrix coniferricola. The filamentous blue-green alga Anabaena flos-aquae was the only alga that promoted growth in tadpoles and was digested more thoroughly than the other algae. Ability of tadpoles to digest nuisance, bloom-forming algae such as Anabaena has important implications in freshwater resource management. Such results also contribute to a better understanding of the roles tadpoles play in nutrient cycling, their potential to combat eutrophication, and their influence on primary productivity in freshwater ecosystems.

A new procedure for the analysis and purification of naturally occurring anatoxin-a from the blue-green alga Anabaena flos-aquae

K. Harada, Y. Kimura, K. Ogawa, M. Suzuki, A. M. Dahlem, V. R. Beasley and W. W. Carmichael. A new procedure for the analysis and purification of naturally occurring anatoxin-a from the blue-green alga Anabaena flos-aquae. Toxicon 27, 1289–1296, 1989.— Anabaena flos-aquae produces at least two neurotoxins termed anatoxin-a (ANTX-a) and -a(s) [ANTX-a(s)]. ANTX-a is a potent postsynaptic depolarizing neuromuscular blocking agent. Its structure is the secondary amine, 2-acetyl-9-azabicyclo[4.2.1]non-2-ene. Known isolation and analysis methods have not always given satisfactory results. Therefore, an improved procedure was developed for both isolation and analysis of ANTX-a which involves four steps; extraction, clean-up, separation and determination. Extraction was efficiently done with 0.05 M acetic acid, and a reversed phase, ODS (octadecylsilanized) and a cation exchanger (COOH) organosilans bonded to silica gels were applied to a clean-up step. Separation and determination were then performed using two TLC and HPLC chromatographies.

Inhibition of growth of freshwater microalgae by long-chained aliphatic amines employed in solvent extraction processes

The influence on algal growth by six long-chained aliphatic amines, used in industrial solvent extraction processes, was investigated by a conventional algal assay and, in addition, a simple assay where algae were grown in liquid medium in 250 μl cultures on microtitration plates. Loss of solvent extractants from processes to ambient water represent a potential environmental problem. The primary, secondary, tertiary and quaternary amines (with one exception) had EC50-values based on growth rate (ECr) or algal biomass (ECb) at 0.01–0.3 mg/L (20–800 nM). This makes long-chained aliphatic amines about a thousand times more toxic than short-chained amines—on a molar basis. The difference in toxicity was interpreted as being due to different modes of action between the two groups of amines. The diatomAsterionella formosa and the blue-green algaAnabaena flos-aquae were more sensitive to the amines than the green-algaeSelen-astrum capricornutum, Monoraphidium pusillum orChlorella emersonii. The maximum ECmax/ECmin ratio recorded was 19.5, for the primary amine.Anabaena flos-aquae was more sensitive by a factor 2–4 when grown under nitrogen fixation conditions than when supplied with combined nitrogen. Compared to other aquatic organisms, the algae show a particular sensitivity to amines. The microtitration test system was less sensitive than the flask test system. The low sensitivity of the microtitration test system is not an inherent property, but due to the use of an insensitive technique (visual inspection) for detection of algal biomass. The ECr50 and ECb50-values in the flask test system were both heavily time-dependent.

Effect of microbial life stages on the fate of methylmercury in natural waters.

The transformations of methylmercury in water under a variety of conditions somewhat similar to those found in nature were studied. The transformations were studied primarily in Ottawa River water, to which had been added a natural organic-rich clay sediment, living or thermally killed bacteria (Escherichia coli and Pseudomonas fluorescens) or the blue-green alga Anabaena flos-aquae. In addition, transformations of methylmercury caused by growing bacteria were studied. Results show that growing bacterial cells can transform mercury and methylmercury to volatile form which is readily lost to the aquatic environment. Living but non-growing bacterial and algal cells cause the demethylation of methylmercury to mercury and dead bacterial cells can lead to methylation of mercury to methylmercury. (JMT)

The Role of Potassium in the Control of Turgor Pressure in a Gas-Vacuolate Blue-Green Alga

The contribution of K+ accumulation to cell turgor pressure was investigated in the gas-vacuolate blue-green alga Anabaena flos-aquae. The cell turgor pressure, measured by the gas vesicle method, drops in cells suspended in culture medium depleted of K+ but rapidly rises again, by 100 kPa or more, when K+ is resupplied. A similar though rather slower rise in turgor pressure is supported by an equivalent concentration of Rb+. The internal K+ concentration rose from 66 to 91 mM when K+ was supplied at an external concentration of 0-4 mM. This rise was light-dependent. Greater increases in internal K+ concentration and turgor pressure occurred when K+ was supplied at a higher concentration, 3-6 mM. In both cases over 60% of the observed turgor pressure rise could be accounted for by accumulation of K+. The turgor pressure rise supported by light-stimulated K+ uptake can cause collapse of enough of the alga's gas vesicles to destroy its buoyancy. The effect of K+ availability on buoyancy regulation by planktonic blue-green algae is discussed.

Regulation of glutamine synthetase in the blue-green alga Anabaena flos-aquae

Glutamine synthetase (GS) was isolated from log phase cells and purified to a single protein as evidenced by gel electrophoresis. Protamine and ammonium sulfate precipitation and chromatography on DEAE-cellulose and Bio-Gel resulted in 380-fold purification. The enzyme was most sensitive to alanine (85% inhibition at 0.1 mM) but was also inhibited by glycine, arginine and serine. Combinations of inhibitory amino acids or nucleotides (AMP, ADP, ATP) exhibited cumulative inhibition. Cooperative inhibition was noted with CTP and any single nucleotide. Inhibition by CTP alone was uncompetitive with respect to glutamine. The enzyme was also regulated by the energy charge of the cell.

The effect of two organophosphate insecticides on the growth of freshwater algae

Seven freshwater algae were grown in the presence of Abate® 4-E (O,O,O′,O′-tetramethyl-O,O′-thiodi-p-phenylene phosphorothioate) and Dursban® M-3633 (O,O-diethyl-O-(3,5,6-trichloro-2-pyridyl) phosphorothioate) at 1,10, and 100 μg/ℓ active ingredient. The response of different algal groups to the insecticides was highly variable.The growth rate of the nitrogen-fixing blue-green alga Anabaena flos-aquae was increased from 22% at 10 μg/ℓ Abate to 58% at 100 μg/ℓ Abate when grown on nitrogen-free medium. Dursban caused similar growth stimulation. The green alga Chlamydomonas reinhardii showed growth stimulation in response to 100 μg/ℓ Dursban.Significant decreases in growth rate were observed for the green alga Chlorella pyrenoidosa after treatment with 10 μg/ℓ Abate (8%) and 100 μg/ℓ Dursban (12%). The diatom Navicula pelliculosa gave decreases in growth rate of the same order with 10 μg/ℓ Abate or Dursban.No significant effect on the growth rates of the diatom Navicula minima or the blue-green algae Coccochloris peniocystis, Oscillatoria sp., and Anabaena flos-aquae grown in the presence of nitrate was detected after treatment with either insecticide.

Isolation and properties of a ferredoxin from Anabaena Flos-Aquae

Ferredoxin was isolated from the blue-green alga Anabaena flos-aquae. Its homogeneity was shown by conventional and SDS-polyacrylamide gel electrophoresis, and isoelectric focusing on polyacrylamide gel columns, the latter indicating a pI at ca pH 3·7. The absorption spectrum had, in the oxidized state, maxima at 462, 421, 327 and 276 nm, with a shoulder at 284 nm, a spectrum characteristic of plant-type ferredoxins. The 421 : 276 nm absorbance ratio was typically 0.49. The ferredoxin effectively mediated the photoreduction of NADP + by barley chloroplasts depleted of native ferredoxin. The MW obtained by sedimentation-equilibrium and sedimentation velocity-diffusion coefficient studies was ca 12 000 daltons, a value somewhat higher than suggested by amino acid composition data. The ferredoxin contained 2Fe and 2S per molecule.

Dark assimilation of acetate-14C by Anabaena flos-aquae

Acetate is assimilated in both light and dark by the blue-green alga Anabaena flos-aquae. Light uptake has an apparent Km of 6.0 mM and a maximum velocity of 6.0 μmoles/g per hour while the dark uptake rate is lower and proportional to external acetate concentration between 5 and 100 mM.Only 2 to 7% of the acetate-1-14C taken up in the dark is oxidized to 14CO2, and 4 to 5 times as much 14CO2 is released from acetate-1-14C as from -2-14C. Fluoroacetate and α-hydroxypyridyl methane sulphonate inhibit the uptake and release of 14CO2 from acetate in the dark. Radioactivity from acetate-14C is incorporated in the dark mainly into lipids and two amino acids, glutamic acid and leucine. Small amounts of radioactivity are incorporated into a restricted number of organic and α-keto-acids, and triose and hexose phosphates. These results are interpreted as indicating a lack of oxidation of acetate in the dark by a tricarboxylic acid cycle.

The Interrelations of Cell Turgor Pressure, Gas-vacuolation, and Buoyancy in a Blue-green Alga

The increase in pressure required to collapse gas vacuoles on suspending the cells of the blue green alga Anabaena flos-aquae in hypertonic sucrose solutions shows the turgor pressure to vary over the range of 265 to 459 kX m-2 under different culture conditions. The cell turgor increased at a rate of up to 94 kN m-2 h_1 on transferring the alga from low to high light intensity. This rise appears to be a result of the accumulation of photosynthate, as it is dependent on the presence of carbon dioxide in the gas phase and is inhibited by DCMU. Experiments using 14C02 indicate that the increased rate of photosynthesis during the high light exposure is easily sufficient to account for the observed turgor rise. The rise in turgor can bring about collapse of sufficient of the alga's gas vacuoles to destroy its buoyancy. Higher turgor pressures, and consequently a lower degree of gas vacuolation and buoyancy, were maintained when the alga was kept at high light intensities for a week and more. The significance of this behaviour is discussed in relation to stratification of planktonic blue-green algae in natural habitats.

The electrophoretic characterization of ribosomes from the blue-green alga Anabaena flos-aquae.

0946 09 1. Ribosomes of the blue-green alga, Anabaena flos-aquae, were isolated using a rapid lysis method and by grinding with alumina. 2. Analysis of ribosomes obtained by rapid lysis on sucrose gradients and electrophoretic gels indicated the presence of 30S, 50S, 70S, and 100S sibosomes as well as polysomes. 3. Dissociation of algal 70S and 100S ribosomes into their 30S and 50S subunits was demonstrated using a 6000xg preparation on a two-dimensional electrophoretic gel as well as a 105000xg fraction on a sucrose gradient. 4. Differences between blue-green algal and bacterial ribosomes were noted when 105000xg fractions of both were washed in ribosomal washing buffer. A major 100S or dimer peak was observed for the bacterial preparation before and after washing. The major peak in the algal preparation shifted from 100S to 70S after washing.

Chemical composition of gas vesicles isolated from Anabaena flos-aquae.

Chemical analysis of purified preparations of gas vesicles isolated from the filamentous blue-green alga Anabaena flos-aquae has shown that they are similar in composition to those isolated from the unicellular alga Microcystis aeruginosa by Jones and Jost (1970), being proteinaceous structures, free of lipid and carbohydrate. The gas vesicle protein from Anabaena contains the same 14 amino acids, in broadly the same proportions; in addition there is a small proportion of proline. No sulphur-containing amino acids are present. The empirical formula, suggested by the amino acid ratios, indicates a molecule of 15000 MW.

A study of the strength and stability of gas vesicles isolated from a blue-green alga.

The strength of intact gas vesicle membranes isolated from the bluegreen alga Anabaena flos-aquae was investigated under different physical and chemical conditions some of which might be important in determining their stability in living cells. High concentrations of urea and of divalent cations, pH's above 9 and below 7, exposure to proteolytic enzymes and temperatures over 40°C, all resulted in weakening of the gas vesicles, as indicated by changes in their range of critical-collapse pressure. Detergents gave no apparent increase in critical pressure, suggesting that the interfacial tension at the outer surface of the membrane is very small.

The fine structure of gas-vacuoles released from cells of the blue-green alga Anabaena flos-aquae

Cells of the blue-green alga Anabaena flos-aquae were ruptured and the gas-cylinders, which comprise the gas-vacuoles, were released. The gas-cylinders released retained their same shape and structure: 70 mμ or more wide, 0.2–0.9 μ long, with conical ends. Staining with phosphotungstic acid showed the membrane to be made up of particles arranged in rows, about 5 mμ apart, running round the cylinder at right angles to the long axis. Some of the cylinders became flattened during the preparation. Rounding-off of the gas-cylinders on isolation, described by others, was not encountered. However, some of the isolated gas-cylinders were considerably wider than 70 mμ and it is possible that they tend to shorten and widen on isolation from the cell.