The Effects of Threonine on Population Changes and Virulence of Salmonella Typhimurium

Neisseria gonorrhoeae II. Colonial Variation and Pathogenicity During 35 Months In Vitro

“…In spite of these genotypic and phenotypic fluctuations, virulence and colonial morphology in Ti and T2 colonies remained inseparable. A relationship between virulence and colonial morphology has been observed in other genera of bacteria (1,2,7,14); however, in most cases, this has been either an association of colonial morphology with a degree of virulence or an associa-. tion of these two characteristics in which either could vary independently of the other.…”

GLYCINE RESISTANCE IN AGROBACTERIUM TUMEFACIENS

“…The effects of the selection of mutants resistant to amino acids on virulence have beeii investigated in Brucella (Goodlow, Mika, and Braun, 1950;Goodlow et al. 1952) and Salmonella typhimurium (Page, Goodlow, and Braun, 1951). The lpresent paper reports experiments designed to test the assumption that the selection of glycine-resistant mutants is involved in the attenuation of A. tumefaciens and to determine the fate of nonresistant bacteria in media containing high glycine concentrations.…”

THE EFFECT OF SALMONELLA PULLORUM INFECTION ON AMINO ACIDS OF THE CHICK

“…It was shown by Holtman and Page in 1950 (unpublished data) that an experimental increase in the blood level of threonine in guinea pigs infected with Salmonella typhimurium resulted in a marked reduction of survival time. This amino acid, in vivo, was later demonstrated by Page, Goodlow, and Braun (1951) to induce significant bacterial population changes resulting in the establishment of variants of increased virulence. Whether this type of amino acid effect occurs during the progress of natural infection has not been determined although it is evident that the free amino acid levels of the blood may be reduced during the course of disease.…”