DRUG RESISTANCE OF ENTERIC BACTERIA. IV. ACTIVE TRANSDUCING BACTERIOPHAGE P1 CM PRODUCED BY THE COMBINATION OF R FACTOR WITH BACTERIOPHAGE P1

Kondo, Eiko (Gunma University, Maebashi, Japan), and Susumu Mitsuhashi. Drug resistance of enteric bacteria. IV. Active transducing phage P1 CM produced by the combination of R factor with phage P1. J. Bacteriol. 88:1266-1276. 1964.-During an investigation of the transduction of R factors with phage P1, a phage lysate capable of transducing the character of chloramphenicol resistance (CM(r)) in extremely high frequency was obtained. The transduction of the CM(r) character with the lysate was consistently accompanied by lysogenization with the phage used for transduction. This lysate exhibits no beneficial effect with normal P1, and no effect is produced by decreasing the multiplicity of infection. A single infection with the phage allows the formation of plaques as well as CM(r) lysogenic cells at the center of the plaque. Both the transducing and plaque-forming activities of the lysate were lost by neutralization with anti-P1 phage serum, and its absorption to the host bacteria was enhanced by the addition of Ca(++). Thus, it was concluded that a derivative of P1 phage (P1 CM) was isolated which had not only the ability to transduce the CM(r) character but also the capacity to form plaques; i.e., the CM(r) gene of R factor is specifically associated with the genome of phage P1. No detectable differences were noted between P1 CM and normal P1 phage in density-gradient analyses in CsCl, in stability of lysogenization, in ability to transduce chromosomal markers, and in the mode of induction from lysogenic cells by ultraviolet irradiation. The instance of transduction of the CM(r) character described here may also be considered as an example of lysogenic conversion, in the sense that the alteration in CM(r) character is inseparable from lysogenicity.

THE EVOLUTION OF THE IMMUNE RESPONSE. 3. IMMUNOLOGIC RESPONSES IN THE LAMPREY

1. Studies of the immune response have been carried out in more than 1700 lampreys representing three stages in the life cycle of these animals. 2. Lampreys used in this study were unable to clear certain soluble protein antigens and bacteriophage and were unable to make antibodies to these antigens. Hemocyanin was cleared from the circulation. 3. The immune responses demonstrated in lampreys include the production of specific antibody to killed Brucella cells, the rejection of skin homografts, and the development of a delayed allergic response to old tuberculin. 4. A responsive proliferation of lymphoid cells occurred in the protovertebral arch following antigen-adjuvant stimulation. 5. Electrophoretic and immunoelectrophoretic analysis of lamprey serum revealed gamma globulin. Ultracentrifugal analysis of serum revealed proteins with sedimentation coefficients of 17S, 8S, 7S, and 3S. 6. The antibodies thus far observed in the lamprey are of relatively high molecular weight and destroyed by 2-mercaptoethanol. 7. In the lamprey it would appear that there is reflected the coordinate evolution of a primitive thymus, primitive spleen containing lymphoid foci, a family of lymphocytes in the peripheral blood and capacity for gamma globulin synthesis and expression of adaptive immunity.