The inner open tubular structures that appear to be at least partially detached from the exosporium may represent remnant spore coats which were left behind following germination and emergence.
TEM studies have shown that a considerable portion of the spore coat remained within the exosporium following cell emergence of C. pasteurianum ATCC 6013,
C. botulinum Group I ATCC 3502 and C. botulinum Group II Eklund17B.
Interestingly, as the hole of the tubular spore coat structure is aligned with the opening in the exosporiumstructure, this alignment may be genetically predetermined.
The findings presented here establish the role of the exosporium
and spore coats in germination and cell emergence in