John J. Sasner

Comparison of the toxins of the blue-green alga Aphanizomenon flos-aquae with the Gonyaulax toxins

A toxic strain of Aphanizomenon flos-aquae (NH-1), isolated from a toxic bloom in a pond in Durham, New Hampshire, has been mass cultured in the laboratory. The toxin was extracted by ultrasonic disruption of the cells and purified by; (a) filtration through a 10 kilodalton filter, and (b) chromatography on a strong cation exchange resin column using 0.01 M, then 0.1 M, pH 5, sodium acetate buffer followed by 0.75 M hydrochloric acid. Mouse assays and fluorescence generated by hydrogen peroxide oxidation were used to monitor the fractions. Only a nonfluorescent toxic peak followed immediately by a fluorescent less-toxic peak were detected, both eluting with the hydrochloric acid fractions. The toxins were identical in behavior to neosaxitoxin and saxitoxin, respectively, when compared with elution profiles of the paralytic shellfish poisons from Gonyaulax tamarensis var. excavata and by paper electrophoretic and thin-layer chromatographic comparisons. The toxin profile appears to be different from that of a previously isolated strain of A. flos-aquae from Kezar Lake.

Activity of cyanobacterial and algal odor compounds found in lake waters on green alga Chlorella pyrenoidosa growth

Volatile organic compounds produced by cyanobacteria and algae in freshwater lakes and contributing to the odour of lakes were tested for their ability to inhibit the growth of the green alga Chlorella pyrenoidosa by the paper disk-agar plate method. Geosmin, β-cyclocitral, α- and β-ionones, and geranylacetone exhibited inhibitory activity by diffusion in the 2-5 mg ml−1 range. α- and β-Ionones and geranylacetone showed inhibition through the vapor phase at 10 mg ml−1. Dimethyl disulfide showed no inhibition at 10 mg ml−1. The norcarotenoids, which are prominent contributors to the odour of lake waters, were not significantly active in inhibiting the growth of Chlorella, with activity in the same range as monoterpene alcohols in general.

Physiological and chemical studies on Gymnodinium breve davis toxin

The marine dinoflagellate Gymnodinium breve was cultured under defined conditions and provided toxic material for chemical and physiological studies. Bioassay on mice and fish of ether extracts from cultures, confirmed that potency was related to numbers of cells extracted. A toxic component was isolated from these extracts and partially characterized by chromatographic and spectral methods. A molecular weight of 279 was determined by both osmometry and mass spectrometric analysis. The active material blocks neuromuscular transmission in frog sartorius preparations before rendering the nerve and then the muscle inexcitable to stimuli, but does not alter the transmembrane potential. Synaptic effects are blocked by curare. The primary site of action appears to be at the end plate although the specific mode of action is not clear. Physiological and pharmacological studies using mammalian intestine, vertebrate and invertebrate heart preparations and human serum, indicate anticholinesterase-like activity.

Purification of Aphanizomenon flos-aquae toxin and its chemical and physiological properties

Abstract A toxin in chromatographically pure form has been isolated from natural blooms of the blue-green alga Aphanizomenon flos-aquae . The toxin is a strongly basic substance, which gives a positive ninhydrin reaction and appears to be a guanidine derivative. A dose of 2·7 μg injected intraperitoneally into 20 g mice caused death in 4·9 min. The purified toxin reversibly blocks action potentials and tension development in amphibian nerve-muscle preparations without alteration of the resting potential. The toxin differs from saxitoxin in some of its chemical and physical properties, and some of its effects on neuromuscular systems.

Inhibition of Chlorella growth by the lipids of cyanobacterium Microcystis aeruginosa

The total lipids of the cyanobacterium Microcystis aeruginosa have been isolated and fractionated into its components. Of these lipid components, only the fatty acid-containing fraction inhibited the growth of the green alga Chlorella pyrenoidosa. The inhibitory activity appears to be due to linoleic and linolenic acids, which are both present in significants quantities. These acids may be the substances responsible for the reported toxicity of Microcystis aeruginosa to Chlorella.

Sodium channels blocked by aphantoxin obtained from the blue-green alga, Aphanizomenon flos-aquae.

Abstract Aphantoxin, an agent contained in some New Hampshire strains of the cyanobacteria, Aphanizomenon flos-aquae , blocks the sodium conductance of the squid axon membrane with no effect on the potassium conductance. Channel blockage by aphantoxin follows a dose-response curve representative of 1:1 stoichiometry, similar to the action of tetrodotoxin and saxitoxin. The blocking effect of aphantoxin appears to be completely reversible.

Reinvestigation of the toxins from the blue‐green alga, Aphanizomenon flos‐aquae, by a high performance chromatographic method

Abstract Toxic red tides due to blue green alga‐Aphanizomenon flos‐aquae are becomming common occurrence in the lakes of New Hampshire. The toxins from Aphaizomenon flos‐aquae were purified by a high performance chromatographic method. One of the toxins was identified as saxitoxin; the other three gave reactions indicating their structural similarity to toxins isolated from Gonyaulax tamarensis.

Inhibition of Chlorella growth by degradation and related products of linoleic and linolenic acids and the possible significance of polyunsaturated fatty acids in phytoplankton ecology

The activity of the degradation products of linoleic and linolenic acids in inhibiting the growth of the green alga Chlorella pyrenoidosa was determined using the paper disk-agar plate method. Although hydroperoxides derived from these acids and aldehyde biodegradation products and other related aldehydes and alcohols showed inhibitory activity, it is concluded from the weakness of the activities that the inhibitory effects of polyunsaturated fatty acids(PUFAs) on Chlorella growth is due mainly to the acids themselves and not their degradation products. The evidence for the possible ecological role of PUFAs as toxic agents against phytoplankton is presented.

Pterins of the cyanobacterium Aphanizomenon flos-aquae

The cyanobacterium Alphanizomenon flos-aquae contains various glycosides of a pterin that had previously been tentatively identified as 6-(threo-1,2-dihydroxypropyl)-pterin. The pterin is now identified as 6-(l-threo-1,2-dihydroxypropyl)pterin(6-l-threo-biopterin) by NMR and mass spectrometry, thinchromatographic comparisons with authentic samples and by optical rotation. The 6-l-threo-biopterin glycoside-1 from toxic strain NH-1 gave rise to xylose and glucose on hydrolysis, whereas its glycoside-2 from Cambridge Collection and nontoxic NH-1 strains gave mannose and glucose. This pterin may be a useful marker for certain species of cyanobacteria.

Lipids of cyanobacteriumAphanizomenon flos-aquae and inhibition ofChlorella growth.

The inhibition of the growth of the green algaChlorella pyrenoidosa by the lipids of the cyanobacteriumAphanizomenon flos-aquae is associated with the fractions containing long-chain unsaturated fatty acids. A sterol present inAphanizomenon has been identified as poriferasterol.