A peptide hepatotoxin was isolated by reversed phase liquid chromatography from the cyanobacterium Oscillatoria agardhii and characterized structurally and toxicologically. Amino acid analyses, proton nuclear magnetic resonance and fast atom bombardment mass spectrometry showed that the toxin is a cyclic heptapeptide (mol. wt 1023.5) with the structure cyclo-(Ala-Arg-Asp-Arg-Adda-Glu-N-methylde...

Glycolate dehydrogenase activity was detected in cell-free extracts of Oscillatoria sp. prepared by osmotic lysis of spheroplasts in 0.05 m potassium phosphate buffer, pH 7.5, containing 0.3 m mannitol. Most of the enzyme activity was found in a particulate fraction and localized in the photosynthetic lamellae after centrifugation in a discontinuous sucrose density gradient. Enzyme activity was...

Article history: Received 29 December 2006 Received in revised form 11 November 2007 Accepted 4 December 2007 In the context of this study two concepts were applied for the development of rule-based agents of algal populations: (1) rule discovery by means of a hybrid evolutionary algorithms (HEA) and rigorous k-fold cross-validation, and (2) rule generalisation by means of merged time-series da...

In recent years there has been a considerable increase in our knowledge of the respiratory metabolism in higher plants. The lower plants, however, have received little attention. This is particularly true of the blue-green algae where the amount of available information on their respiration is almost negligible. The only known investigation has been that of EMERSON (1) who reported that respira...

This is an investigation concerned with studying the possible adaptive response of four different unicellular algae, Anabaena PCC 7120, Oscillatoria angustissima, Scendesmus obliquus and Chlorella vulgaris, to the toxin of Microcystis aeruginosa (Kützing). The effects of four different concentrations, 25, 50, 100 and 200 μg mL-1 of microcystins crude extract of M. aeruginosa, on both intra and ...

A comparative study on the cyanobacterial isolates, Anabaena ambigua Rao (A100) and Oscillatoria foreaui Fremy (A1340) were carried out to investigate the response of an organophosphorus insecticide Divap 100 at different concentrations of 1, 5 and 10ppm on the growth and release of extracellular products such as protein, nitrogen, ammonia, carbohydrates, amino acids and phenols. The experiment...