A sensitive method for measuring oxygen consumption

A technique is presented whereby oxygen consumption rates of the order of 10⁻⁶ μl/hr can be measured, thus providing a means for studying the respiration rates of single cells, even slowly respiring ones. The technique is based on the principle of incubating cells in extremely small chambers containing highly concentrated hemoglobin solutions. The absorbance shift occurring when hemoglobin is transformed from its oxygenated to its deoxygenated form is recorded microspectrophotometrically. The results obtained by this technique seem to be well in accordance with those of the Warburg manometric method. The technique is convenient and easy to handle and the sensitivity can be varied within wide limits, permitting different types of materials to be studied. In experiments using yeast cells, respiration rates from 1.0 × 10⁻⁶ to 1.8 × 10⁻⁶ μl O₂/cell/hr were revealed.