THE OXIDATION OF CARBON MONOXIDE BY FERTILIZED EGGS OF URECHIS CAUPO SHOWN BY USE OF A C LABEL

¹ Division of Biology, California Institute of Technology, Pasadena, California

1. The fertilized eggs of Urechis caupo have been found to oxidize CO to CO₂ both in the light and in the dark. This has been shown by the use of C¹³-labelled CO. In the light there is a previously described increase in gas-uptake in 80% CO/O₂ as compared with air. All of this excess gas-uptake can be attributed to the oxidation of CO.

2. In the dark the percentage of respiratory CO₂ derived from CO is less than in the light. If the oxidation of CO is subtracted from the total gas uptake, the "ordinary" respiration is shown to be inhibited about 29% in the dark by 80% CO/O₂.