Unexpectedly, the ''military'' lineages were also marked by the loss of catalase activity, whose presence is an identifying feature of both B. subtilis and B. atrophaeus [13] . This activity was present in a separate lineage of in vitro passaged organisms, so it is not immediately clear why ''military'' isolates, i.e. those subjected to selection within the early days of the development of BG as a simulant organism, would have lost the catalase activity characteristic of the parental isolate. Because the KatA gene product is not found in spores [41, 71] , we consider it unlikely that the absence of this activity would impact the resistance of spores to decontamination reagents, and thus any antioxidant resistance phenotype exhibited by spores of ''military'' isolates would likely have gone unnoticed. However, direct comparisons of the ''military'' B. atrophaeus lineages to the progenitor strains have not been done, and pleiotropic effects of a spo0F mutation on spore physiology cannot currently be excluded.