▁curve , ▁and ▁the ▁imm ature ▁sp ore ▁is ▁surrounded ▁by ▁a ▁double ▁memb rane ▁of ▁the ▁mother ▁cell ▁in ▁an ▁eng ulf ment ▁process , ▁similar ▁to ▁ph ag oc yt osis , ▁and ▁the ▁smaller ▁for esp ore ▁becomes ▁entirely ▁contained ▁within ▁the ▁mother ▁cell . ▁ ▁Stage ▁IV : ▁The ▁mother ▁cell ▁medi ates ▁the ▁development ▁of ▁the ▁for esp ore ▁into ▁the ▁sp ore . ▁The ▁inner ▁and ▁outer ▁protein ace ous ▁layers ▁of ▁the ▁sp ore ▁are ▁assemble d , ▁and ▁the ▁sp ore ▁cor tex , ▁consisting ▁of ▁a ▁thick ▁layer ▁of ▁pe pt id og ly c ans ▁contained ▁between ▁the ▁inner ▁and ▁outer ▁sp ore ▁memb ran es , ▁is ▁synth es ized . ▁Furthermore , ▁calci um ▁dip icol inate ▁accum ul ates ▁in ▁the ▁nucle us . ▁ ▁Stage ▁V : ▁The ▁sp ore ▁coat ▁is ▁synth es ized , ▁consisting ▁of ▁ ∼ 8 0 ▁prote ins ▁depos ited ▁by ▁the ▁mother ▁cell , ▁and ▁is ▁arranged ▁in ▁inner ▁and ▁outer ▁layers . ▁ ▁Stage ▁VI : ▁Sp ore ▁m atur ation ▁occurs ▁during ▁this ▁stage , ▁and ▁the ▁sp ores ▁become ▁resist ant ▁to ▁heat ▁and ▁organ ic ▁sol vent s . ▁ ▁Stage ▁VII : ▁L yt ic ▁en zym es ▁dis rupt ▁the ▁mother ▁cell , ▁re le asing ▁the ▁m ature ▁sp ore ▁( Err ington , ▁ 2 0 0 3 , ▁H igg ins ▁and ▁D work in , ▁ 2 0 1 2 , ▁Set