This project offers a unique solution to the problems associated with identifying, sorting and assessing the physiological status of zooplankton. Molecular techniques will be developed that can rapidly identify and quantify the level of expression of physiologically significant genes in the copepod, Calanus finmarchicus. These techniques take advantage of the specificity and sensitivity of the polymerase chain reaction (PCR) to quantitatively amplify species-specific mRNAs that encode enzymes that regulate metabolic flux. In order to design the necessary primers for PCR, the cDNAs that encode for the enzymes, hexokinase, phosphofructokinase, phosphoglucose isomerase and citrate synthetase will be cloned utilizing the phylogenetically conserved primary sequences of these enzymes. Species-specific primers will be designed from these cDNA sequences and used to quantitatively amplify each enzyme's mRNA only from C. finmarchicus to ascertain the affect of environmental parameters on the level of enzyme expression. Differences in the quantity of C. finmarchicus present in a taxonomically complex assemblage of zooplankton will be normalized by simultaneously measuring the specific concentration of a physiologically invariant gene, such as actin. The results will be equivalent to enzyme per weight of C. finmarchicus, a unit comparable to more traditional physiological studies.
