▁cell ▁wall , ▁and ▁one ▁side ▁then ▁eng ul fs ▁the ▁other . ▁They ▁are ▁not ▁true ▁sp ores ▁( i . e ., ▁not ▁an ▁off spring ). ▁ ▁End osp ore ▁formation ▁originally ▁defined ▁the ▁genus , ▁but ▁not ▁all ▁such ▁species ▁are ▁closely ▁related , ▁and ▁many ▁species ▁have ▁been ▁moved ▁to ▁other ▁gener a ▁of ▁the ▁F irm ic utes . ▁Only ▁one ▁end osp ore ▁is ▁formed ▁per ▁cell . ▁The ▁sp ores ▁are ▁resist ant ▁to ▁heat , ▁cold , ▁radiation , ▁des ic cation , ▁and ▁dis in fect ants . ▁Bac ill us ▁anth rac is ▁needs ▁o xygen ▁to ▁sp or ulate ; ▁this ▁constraint ▁has ▁important ▁consequences ▁for ▁ep ide mi ology ▁and ▁control . ▁In ▁v ivo , ▁B . ▁anth rac is ▁produces ▁a ▁pol ype pt ide ▁( poly gl ut am ic ▁acid ) ▁caps ule ▁that ▁protect s ▁it ▁from ▁ph ag oc yt osis . ▁The ▁gener a ▁Bac ill us ▁and ▁Clo str id ium ▁const itute ▁the ▁family ▁Bac il lace ae . ▁Species ▁are ▁identified ▁by ▁using ▁morph olog ic ▁and ▁bio chem ical ▁criteria . ▁ ▁Because ▁the ▁sp ores ▁of ▁many ▁Bac ill us ▁species ▁are ▁resist ant ▁to ▁heat , ▁radiation , ▁dis in fect ants , ▁and ▁des ic cation , ▁they ▁are ▁difficult ▁to ▁eliminate ▁from ▁medical ▁and ▁ph arma ce ut ical ▁materials ▁and ▁are ▁a ▁frequent ▁cause ▁of ▁cont am ination . ▁Bac ill us ▁species ▁are