Perforation patterns in the peptidoglycan wall of filamentous cyanobacteria

Abstract

Ultrastructural studies were made on seven genera of filamentous cyanobacteria from Sections HI and IV (in the Rippka classification): Oscillatoria limosa Ag. ex Gomont, Spirulina subsalsa Turp. ex Gomont, Crinalium epipsammum Crow, Nostoc commune Vaucher ex Born. et Flah., Anabaena variabilis Kutzinger ex Born. et Flah., Arthrospira maxima Stizenb. ex Gomont, Arthrospira platensis Stizenb. ex Gomont, and Cyanospira rippkae Florenzano. Perforation types and their distribution in the peptidoglycan layer observed in Crinalium epipsammum Crow were similar to those in Oscillatoria limosa and two Arthrospira strains. In Cyanospira and Anabaena no junctional perforations in the peptidoglycan wall layer were observed; however, intracellular perforations were documented. Except for Spirulina, the perforations were organized in rows (up to 10) placed on both sides of the cross wall. In the Spirulina cross sections, perforations were found only in the thickened, inner part of the cell wall. The perforation patterns in Spirulina and Arthrospira strains were clearly different and justify the separation into different genera.