• Anabaena spiroides;
  • capsules;
  • culture;
  • fragmentation;
  • freshwater;
  • lyses;
  • TEP formation

We report the production of large numbers of transparent exopolymer particles (TEP) from polysaccharidic capsules of Anabaena spiroides Kleb. in cultures. Two biotic pathways of TEP formation were observed: (1) fragmentation of small portions of the capsules, which occurred throughout the growth phases; and (2) transformation of the whole polysaccharidic capsules into TEP, following cellular lyses in the aging culture. Photographic documentation of these processes was performed after staining small aliquots of the samples with Alcian Blue and negative staining with India ink. Concentrations of TEP were determined in distinct culture growth phases using semiquantitative Alcian Blue staining. Concentrations of TEP increased throughout the experimental time, while Alcian Blue remaining in solution decreased. Decreasing concentrations of chl a indicated cellular death, and by the end of the experiment, TEP formed by both pathways accumulate in the culture medium. These results show that virtually all dead chains of A. spiroides are transformed into TEP in the aged culture.