A Review on the Radioisotopic Methods for Measuring Bacterial Production in Aquatic Environments

Advantages and disadvantages of four radioisotopic methods, $^{3}H$-thymidine, $^{3}H$-adenine, $^{3}H$-leucine, and $^{35}S$-sulfate, for measuring bacterial production were reviewed. The maior issues discussed in production methods were: (1) whether all the actively growing bacteria take up the radiolabeled (organic) tracers; (2) how each target molecule should be purified (nonspecific labeling); and (3) how important the determination of the precursor pool specific activity is (internal isotope dilution). Since all the radioisotoic methods have their own advantages and disadvantages, careful consideration must be paid in choosing the radioisotope according to the conditions of each environment investigated.