Observation of symbiotic conformation by SEM. Mixed culture of C. sorokiniana with CSSB-1 (panel A), with CSSB-2 (panel B), with CSSB-3 (panel C), with CSSF-1 (panel D). Symbols: C. sorokiniana (a), CSSB-1 (b), CSSB-2 (c), sheath (d), CSSB-3 (e) and CSSF-1 (f). The size of the white bar is 2 μm.