摘要:

The administration of 6-mercaptopurine (6-MP) to rabbits in dosages of 6 or 12 mg per kg per day resulted in complete blocking of the immuno-conglutinin and antibody responses provided the injections were continued for 5 days after the last inoculation of antigen. However, if the administration of 6-MP was discontinued 1 day after the last antigen injection, the immune mechanism escaped from this inhibition and both antibody and immuno-conglutinin were produced. Rabbits injected with the 12 mg dosage level took longer to overcome the inhibition of the immune response and showed weaker responses than rabbits injected with the 6 mg dosage level. Immuno-conglutinin production by heterostimulation and by autostimulation showed a similar pattern to treatment with 6-MP but the immuno-conglutinin response to autostimulation was quantitatively weaker.Rabbits injected with colchicine gave a slightly higher immuno-conglutinin response in heterostimulation experiments but a somewhat lower response in autostimulation experiments when compared with animals not receiving the drug.

ISSN:0008-4166    

DOI:10.1139/m65-011

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

Four phages ofA.radiobacter, isolated from sewage and soil, required divalentions for multiplication. Chelating agents inactivated free phage irreversibly. With citrate and phosphate the order of decreasing sensitivity of the phages was PR-590a > PS-192 > PsR-1012 > PR-1001. EDTA was the most inhibitory. Phage growth was promoted by the addition of 10−3 Mof Ca++or Mg++in a divalent ion-free medium. These ions were required for the adsorption step in the growth cycle of phage PR-1001. Latent periods of the four phages in nutrient broth ranged from 35 to 37 minutes for PsR-1012 and 42 to 45 minutes for PR-590a. Burst sizes were 65, 27, 56, and 69, and percentage adsorptions after 5 minutes were 35, 12, 36, and 43 for PR-1001, PS-192, PR-590a, and PsR-1012, respectively. The optimum temperature for adsorption and yield of phage PS-192 was 25 °C while the shortest latent period occurred at 30–32 °C. At 35 °C this phage failed to multiply.

ISSN:0008-4166    

DOI:10.1139/m65-012

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

The fine structure of phage-infectedStreptomyces griseushyphae was examined using ultrathin sections and electron microscopy. The intracellular phage was observed to be uniformly distributed throughout the cytoplasm. The diameter and hexagonal shape of the head compared well with shadowed phage preparations. Alterations in fine structure centered on irregular cell wall disintegration, plasma membrane disruption, and leakage of cytoplasmic components.

ISSN:0008-4166    

DOI:10.1139/m65-013

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

Soil organisms belonging to the myxobacter group and predatory on molds, yeasts, nematodes, and streptomycetes as well as on a wide range of bacteria elaborate at least two extracellular enzymes: a protease and a lysin. The protease hydrolyzes casein and haemoglobin and is inactive against bacterial cell walls while the lysin hydrolyzes bacterial cell walls but is inactive on proteins. These enzymes have been separated on hydroxylapatite columns and some of their properties are described. The predatory action of many of the isolates may be explained by the secretion and subsequent action of these two enzymes.

ISSN:0008-4166    

DOI:10.1139/m65-014

出版商:NRC Research Press    

年代:1965

数据来源: NRC

ISSN:0008-4166    

DOI:10.1139/m65-015

出版商:NRC Research Press    

年代:1965

数据来源: NRC

ISSN:0008-4166    

DOI:10.1139/m65-016

出版商:NRC Research Press    

年代:1965

数据来源: NRC

ISSN:0008-4166    

DOI:10.1139/m65-017

出版商:NRC Research Press    

年代:1965

数据来源: NRC