Sentence:  How can the results of <WSD>crossfeeding</WSD> trials be used to sequence mutant strains of the bacteria Serratia marsescens in the biosynthetic pathway for the production of prodigiosis? 
Meaning of the word marked with <WSD> tags:  To coexist on a single limiting resource where one strain or species grows on the primary resource and the second grows on the partially degraded resource excreted by the first.