GROWTH OF AZOTOBACTER IN DEUTERIUM OXIDE

Johnstone , D. B. (University of Vermont, Burlington). Growth of Azotobacter in deuterium oxide. J. Bacteriol. 83: 867–870. 1962.—To the small list of bacteria that are reported to have been cultured in fully deuterated media can be added Azotobacter agilis and A. vinelandii . Moreover, these bacteria, although growing in a deuterium oxide medium with deuterated carbon sources, will fix atmospheric nitrogen. Lag periods occur prior to growth, and wide morphological variation is apparent during adaptation to a deuterated environment. A convenient method is presented for measuring, by infrared spectroscopy, the amount of water that accumulates in a D 2 O medium; during incubation this amounts to about 1% per day. Prevention of this accumulation of water indicates that growth, after a lag period, probably is not supported by accumulated hydrogen.

Blockade of Deoxyribonucleic Acid Synthesis by Deuterium Oxide

Interference with deoxyribonucleic acid replication need not be a primary mechanism in the blockade of cell division by deuterium oxide, but current hypotheses on the molecular basis of the blockade do suggest that such interference might take place under appropriate conditions. Autoradiographic experiments support the suggestion, for whereas normal sea urchin eggs incorporate H(3)-thymidine into deoxyribonucleic acid from almost the beginning of development, cells immersed in deuterium-enriched media do not. Blockade of mitosis and inhibition of thymidine incorporation are simultaneously relieved when the eggs are returned to normal water.