Tomlinson, Geraldine A. (University of British Columbia, Vancouver, B.C., Canada) and J. J. R. Campbell. Patterns of oxidative assimilation in strains of Pseudomonas and Achromobacter. J. Bacteriol. 86:434–444. 1963.—Oxidative assimilation of glucose-U-C14 in the absence of added nitrogen was studied by use of washed-cell suspensions of Pseudomonas aeruginosa, P. fluorescens, Achromobacter strain B81, and Achromobacter viscosus (Alcaligenes viscolactis). The suggestion that oxidative assimilation in these organisms is the reincorporation of endogenously produced ammonia by way of α-ketoglutarate is tenable. Each of the four organisms accumulated intermediate compounds which acted as pacemakers for the oxidation of glucose. This phenomenon, partly because it ensured the availability of additional ammonia, undoubtedly increased the degree of oxidative assimilation. Products accumulating in the supernatant fluids during glucose oxidation were α-ketoglutarate, pyruvate, gluconate, a low molecular weight carbohydrate, and dicarboxylic acids. No two bacteria formed the same products. Assimilation of radioactivity into the cells, which accounted for 12 to 26% of the available C14, continued as long as an oxidizable substrate was present, and was paralleled by uptake of endogenously produced ammonia. During the early stages of glucose oxidation, compounds of the cold trichloroacetic acid-soluble pool constituted a major portion of the total radioactivity of the cells. The lipid fractions of P. aeruginosa and Achromobacter B81 were also of high relative activity during this time. The labeling of the nucleic acid fractions of all four bacteria increased with time, more radioactivity being found in fractions from the two Achromobacter species than in those from the pseudomonads. At the completion of the experiment, the largest percentage of incorporated radioactivity was present in the protein fractions. One of the organisms, Achromobacter B81, synthesized a high molecular weight carbohydrate material.