A high incidence of spontaneous lower-limb paralysis occurred in a population of wild mice (Mus musculus) which had a high incidence of naturally occurring lymphoma and elevated indigenous type-C virus activity. Experimental transmission evidence indicated that both the neurologic and lymphomatous disorders almost certainly were caused by the indigenous type-C virus. The virus appeared to have a direct neurotropic effect on anterior horn neurons in the lower spinal cord.

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JULIUS E. OFFICER. Inhibition of the growth of agents of the psittacosis group by D-cycloserine and its specific reversal by D-alanine. J. Bacteriol. 85:707-711. 1963.-D-Cycloserine inhibited multiplication of four members of the psittacosis group in chick embryo yolk sac. D-Alanine reversed each inhibition. In infections with the agent of mouse pneumonitis, the most sensitive member of the psittacosis group tested, D-alanine competitively antagonized the growth inhibition produced bv D-cycloserine. Of a number of other potential reversing agents, only DL-alanyl-DLalanine reversed the effect of D-cycloserine on mouse pneumonitis agent. The significance of the susceptibility of the psittacosis group to D-cycloserine is discussed in light of the known mode of action of this antibiotic on bacteria. The growth-inhibiting effect of D-cycloserine (D-4-amino-3-isoxazolidone) on bacteria is competitively reversed by its structural analogue, D-alanine (Bondi, Kornblum, and Forte, 1957; Shockman, 1959; Morrison, 1962; Zygmunt, 1962). This relationship may be explained by the findings of Strominger, Ito, and Threnn (1960) that D-cycloserine inhibits both the alanine racemase and the D-alanyl-D-alanine synthetase of Staphylococcus aureus and that D-alanine competitively reverses the D-cycloserine inhibition of both reactions. Neuhaus and Lynch (1962) recently reported similar observations. Since D-1 A preliminary account of this work was presented at the Annual Meeting of the American Society for Microbiology, Kansas City, Mo.,

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A neurogenic paralysis of the lower limb can be induced and serially transmitted in mice by a nontransforming type C virus strain that originated in an embryo of a wild mouse. The virus exerted a neurotropic effect on the anterior horn neurons.