Mitochondrial respiration Mitochondrial dysfunction is responsible for >30 pathological conditions. Some of which can be detected by changes to oxidative phosphorylation patterns e.g. by changes in P/O ratios.
Apoptosis Since mitochondria are highly implicated in apoptosis, changes to cellular respiratory metabolism can be used as an important indicator of apoptosis mechanisms.
Cytotoxicity The potential role of respirometry in cytotoxicity research on drug discovery, development of novel bacteriocides etc is only just being realized. Almost any drug-induced change to a metabolic pathway will theoretically result in a change in energy metabolism. Respirometry can therefore be used, for instance, to establish time/dosage responses over very short timeframes.
New product toxicity In order to obtain a production license, all chemical manufacturers have to establish the toxicity of any new chemical to be manufactured for bulk use, using the OECD 209 test. This measures the respiration inhibition of activated sludge bacteria when exposed to a range of concentrations of the chemical.
Environmental toxicity Present tests of toxicity of effluents discharged to rivers and oceans, use LC50 tests on target aquatic organisms. A more useful test is the EC50 test of respiration inhibition. This is a rigorous test and has the advantage that the test organisms do not need to be killed.