Nitrogenous compounds as substrates for endogenous respiration in microorganisms.

The endogenous substrate of Pseudomonas aeruginosa has been reported to be nitrogenous in nature, as was evident by the marked and quantitatively predictable production of ammonia during endogenous respiration and it was concluded that amino acids were the nitrogenous substrates involved. Further, it was shown that on the addition of an oxidizable substrate, the ammonia which had accumulated in the medium was rapidly assimilated by the resting cells (Warren, Ells, and Campbell, 1960). Although Lamanna and Mallette (1953) state that endogenous substrates vary with the different bacterial species, little definite information as to their actual nature is available. It was felt that an indication of the general distribution and importance of nitrogenous endogenous substrates could be established by correlating ammonia production with the endogenous oxygen consumption of a number of bacterial species. In addition, the general significance of the observation that endogenously produced ammonia was reincorporated into the cell on the addition of oxidizable substrate, could be determined.