Characterization of morphospecies and strains of Pseudanabaena (Cyanophyceae) from laboratory cultures using antibodies and lectins

Immunofluorescence assays using polyclonal and preadsorbed antibodies as we ll as FITC-labelled lectins were employed to characterize two morphospecies of the cyanophytes Pseudanabaena catenata and P. planctonica from laborato ry cultures isolated from two reservoirs in Spain and one in Denmark. Bindi ng of both antibodies and lectins was unaffected by phase of the cell divis ion cycle, growth phase and environmental factors such as culture medium, l ight or temperature. Good-quality polyclonal antibodies were obtained for s everal strains of both morphospecies. As expected, different morphospecies from the same location do not share common antigens while strains of the sa me morphospecies grown in different reservoirs do share most of their surfa ce antigens. However, P. catenata grown at La Pinilla (Spain) does not shar e common antigens with P. catenata from Bastrup (Denmark). Geographical bar riers, in this case, seem to play an important role in determining surface antigen diversity. Similar results are obtained when lectins are used, and some lectins are found to be useful tools for differentiating clones of the same morphospecies. From a genetic point of view there may be no clear spe cies boundary for some morphospecies of cyanobacteria. A 'fuzzy species' co ncept, i.e, a species that belongs in part to more than one species or has characteristics of more than one species, is speculatively considered to ex plain genospecies boundaries of cyanobacteria.