Ensign, Jerald C. (University of Illinois, Urbana), and R. S. Wolfe. Nutritional control of morphogenesis in Arthrobacter crystallopoietes. J. Bacteriol. 87:924-932. 1964.-Arthrobacter crystallopoietes exhibits the cyclic, morphological variation which is a characteristic of this genus. A simple chemically defined medium was developed in which this organism is restricted to growth and division entirely in the coccoid form. Addition singly to this medium of l-arginine, l-phenylalanine, l-asparagine, l-lysine, succinate, malate, fumarate, lactate, or butyrate results in the formation of the rod-shaped stage. A large number of other compounds either increase, have no effect on, or inhibit growth without inducing morphological change in the organisms.