Algal production of extra and intra-cellular polysaccharides as an adaptive response to the toxin crude extract of Microcystis aeruginosa

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 microcystisaeruginosa (kützing). the effects of four different concentrations, 25, 50, 100 and 200 ?g ml-1 of microcystins crudeextract of m. aeruginosa, on both intra and extra-cellular polysaccharide levels, in log phase, of the four tested algaewere studied. the obtained results showed differential increase in the production levels for both intra andextra-cellular polysaccharides by the tested algae, compared with the control. s. obliquus and c. vulgaris showed aresistance to crude toxin higher than anabaena pcc 7120 and o. angustissima. the highly production ofpolysaccharides by green algal species under this toxic stress indicated the involvement of these polysaccharides inprotecting the algal cells against toxic species and, reflect the biological behavior of particular algal species to theenvironmental stresses.