Phytohemagglutinin And Light-induced Charge Density Effects On Plasma Membrane Of Plectonema Boryanum

Effects of the plant lectin phytohemagglutinin M (PHA-M) and illumination on the electrophoretic mobility (EPM) and 90°-light scattering of suspension of spheroplasts obtained by lysis of the unicellular diazothrophic cyanobacterium Plectonema boryanum were studied. Cells cultures were grown on media with different iron content: an iron-deficient (denominated as “Fe-starved” culture), an iron-sufficient (“Fesufficient”), and a twentyfold iron excess medium (“Fe-excess”). Lectin addition led to a decrease of the membrane charge density and aggregation of the vesicles. Our results indicate significant influence of the Fe and illumination on the lectin-induced decreasing of EPM and light scattering intensity. *Corresponding author: E-mail: virjird@biofac.uni-sofia.bg ; Tel.: (00 359 2) 2 8167 281 ; Fax: (00 359 2) 2 865 66 41