x in ▁output ▁until ▁the ▁b acter ial ▁populations ▁are ▁substantial , ▁these ▁b acter ia ▁can ▁generate ▁massive ▁quantities ▁of ▁to x in ▁quickly ▁and ▁thereby ▁sw amp ▁the ▁def ences ▁of ▁the ▁host . ▁ ▁L um ines cent ▁Din of lag ell ates : ▁In ▁early ▁ 1 9 5 4 ▁at ▁North western ▁University , ▁H ast ings , ▁his ▁students ▁and ▁colle agues ▁studied ▁cell ular ▁and ▁mole cular ▁aspects ▁of ▁bi ol um ines c ence ▁in ▁din of lag ell ates ▁[ es pecially ▁L ing ul od in ium ▁poly ed rum ▁( former ly ▁G ony a ul ax ▁poly ed ra ) ]. ▁They ▁el uc id ated ▁the ▁structures ▁of ▁the ▁luc ifer ins ▁and ▁luc ifer ases , ▁the ▁organization ▁and ▁reg ulation ▁of ▁their ▁associated ▁gen es , ▁temporal ▁control ▁mechan isms , ▁and ▁the ▁actual ▁sub - cell ular ▁identity ▁and ▁location ▁of ▁the ▁light ▁em itting ▁elements , ▁which ▁they ▁term ed ▁sc int ill ons . ▁They ▁demonstrated ▁that ▁the ▁reaction ▁is ▁controlled ▁by ▁a ▁drop ▁in ▁p H ▁when ▁an ▁action ▁potential ▁leads ▁to ▁the ▁entry ▁of ▁pro tons ▁via ▁voltage - activ ated ▁memb rane ▁channels ▁in ▁the ▁sc int ill ons . ▁Through ▁imm un ol ocal ization ▁studies ▁the ▁H ast ings ▁lab ▁showed ▁that ▁sc int ill ons ▁are ▁small ▁peri pher al ▁ves icles ▁( 0 . 4 ▁ μ m ) ▁that ▁contain ▁both ▁the ▁luc ifer ase ▁and ▁the