Perforation patterns in the peptidoglycan wall of filamentous cyanobacteria

Ultrastructural studies were made on seven genera of filamentous cyanobacte ria from Sections III and IV (in the Rippka classification): Oscillatoria l imosa Ag, ex Gomont, Spirulina subsalsa Turp, ex:Gomont, Crinalium epipsamm um Crow, Nostoc commune Vaucher ex Born, et Flah,, Anabaena variabilis Kutz inger ex Born. et Flah., Arthrospira maxima Stizenb, ex Gomont, Arthrospira platensis Stizenb, ex Gomont, and Cyanospira rippkae Florenzano, Perforati on types and their distribution in the peptidoglycan layer observed in Crin alium epipsammum Crow were similar to those in Oscillatoria limosa and two Arthrospira strains. In Cyanosipira and Anabaena no junctional perforations in the peptidoglycan wall layer were observed; however, intracellular perf orations were documented. Except for Spirulina, the perforations were organ ized in rows (up to 10) placed on both sides of the cross wall. In the Spir ulina cross sections, perforations were found only in the thickened, inner part of the cell wall. The perforation patterns in Spirulina and Arthrospir a strains were clearly different and justify the separation into different genera.