摘要:

Bacteriophage 317, which virulently infectsRhizobium leguminosarum, has an eclipse period of 60–70 min and a latent period of 100 min at 30°. Electron micrographs of the phage indicated head, tail, and tail-fiber structural components.Base analysis of phage 317 deoxyribonucleic acid (DNA) indicated the presence of equimolar amounts of adenine and thymine and of guanine and cytosine, which suggests that the DNA is double stranded. The DNA has a molecular weight of 41 × 106daltons as determined from electron micrographs.The results of14C-uracil incorporation studies showed that net ribonucleic acid (RNA) synthesis was markedly inhibited after infection. There was a slight stimulation in DNA synthesis after infection as indicated by14C-thymidine incorporation.The results of in vitro assays of enzymes involved in the biosynthesis of DNA showed that deoxyuridine 5′-triphosphate nucleotidohydrolase (dUTPase) and deoxythymidine 5′-monophosphate kinase (dTMP kinase) increased 50- and 30-fold respectively, after infection. The reason for the increased dUTPase activity is not readily apparent. Phage 317 DNA contains only the standard bases, unlike the DNA of other phages that induce an increase in this enzyme after infection. A high level of deoxythymidine 5′-monophosphatase (dTMPase) was observed in both uninfected and infected crude cell extracts. Further work is necessary to see if similar changes occur inRhizobiumduring the establishment of symbiosis with legumes.

ISSN:0008-4166    

DOI:10.1139/m72-060

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

A possible correlation between the skin test and the presence of a cellular mediated immunity has been investigated using a lymphogranuloma venereum (LGV) antigen. The macrophage inhibition (MI) and macrophage spreading inhibition (MSI) tests were used to detect evidence of a cellular mediated immunity. A positive correlation was obtained between the diameter of the skin reactions and the in vitro inhibition of macrophages. Further experimentation demonstrated that the in vitro inhibition of macrophages was not mediated by cytophilic antibodies but mediated partially or completely by a macrophage inhibition factor. Electrofocusing experiments were carried out on a sonicated LGV agent to isolate and identify the antigens which induced the cellular mediated immunity; four fractions with approximate pI (isoelectric point) values of 1.44, 1.38, 10.38, and 12.77 demonstrated a strong inhibition of macrophages in vitro. The antigen containing fractions had smaller amounts of nitrogen, higher ratios of non-reducing sugars per nitrogen content, and extremely high as well as low isoelectric point values as compared with fractions which exhibited no MSI reactions. The possibility of these antigens occurring as repeating units in the structure of the agent is discussed briefly.

ISSN:0008-4166    

DOI:10.1139/m72-061

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Cells ofMycobacterium lepraewere isolated and purified from lepromas, spleen, and liver of leprosy patients. An immunodiffusion analysis of the cytoplasms obtained from four lots ofM.lepraeand 303 strains of different Actinomycetales was performed with the aid of the cytoplasm antisera. Antigenic cross-reactions were found between the cytoplasms ofM.lepraeand certain cytoplasm determinants ofM.avium,M.gallinarum,M.tuberculosis,M.simiae,M.kansasii,Mycococcus capsulatus,Actinomyces israelii,A.naeslundii, and some strains of saprophytic mycobacteria. The results are analyzed for the light they throw on the possible evolution ofMycobacterium leprae. The possibility of developing anM.lepraebased on the antigenic similarities is also discussed.

ISSN:0008-4166    

DOI:10.1139/m72-062

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

An aqueous extract of the soft-shell clam displayed antiviral activity which protected against infection of fathead minnow (FHM) cells by the amphibian virus (LT-1). The extract did not inactivate the virus particle extracellularly, nor could a combined action on virus and cell receptor sites account for the inhibitory effect of the extract. The observed inhibition appeared to be at the intracellular level.

ISSN:0008-4166    

DOI:10.1139/m72-063

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Freeze-etching has revealed the presence of crystalline aggregates closely associated with the developing viral inclusion of vaccinia virus. These have not been observed in frozen uninfected cells or, as yet, in infected cells processed by chemical fixation. Two types apparently exist, linear aggregates composed of cubically packed units, about 10 nm in size, and curved sheets or lamellae in which the subunits, each about 7.5 nm in size, are arranged hexagonally. The precise nature of these aggregates is undetermined, although the latter type is thought by analogy with other poxvirus systems to be related to the surface component of immature virions.

ISSN:0008-4166    

DOI:10.1139/m72-064

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

A partially purified preparation of the constitutive alkaline phosphatase fromNeurospora crassa, containing two electrophoretically distinct activities was used in initial studies of product inhibition patterns. Inorganic phosphate was shown to be a linear competitive inhibitor, andp-nitrophenol to be a non-linear, non-competitive inhibitor ofp-nitrophenyl phosphate hydrolysis. Glycerol was shown to be a linear non-competitive inhibitor of β-glycerophosphate hydrolysis.A purification procedure whereby one enzyme activity could be obtained free of the second was devised. The purified enzyme catalyzed the hydrolysis of a wide range of substrates and had a molecular weight of 111 000. Its hydrolysis of glucose 6-phosphate was competitively inhibited by phosphate and non-competitively inhibited by glucose. Both inhibitions were linear. Hydrolysis ofp-nitrophenyl phosphate was competitively inhibited by phosphate in a linear manner, butp-nitrophenol was a non-linear, non-competitive inhibitor. Alternate product inhibition by glucose was linear competitive. No inhibition byp-nitrophenol of glucose 6-phosphate hydrolysis could be detected.The inhibition data for glucose 6-phosphate and β-glycerophosphate may be consistent with an ordered Uni-Bi mechanism expanded to include one or more isomerizations of enzyme complexes. The postulation of a different mechanism involving alternate pathways is probably required to explain the data obtained whenp-nitrophenyl phosphate was the substrate.

ISSN:0008-4166    

DOI:10.1139/m72-065

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Growth ofRhodotorula aurantiacain a medium supplemented with sulfur amino acids led to the synthesis and accumulation ofS-adenosylmethionine, which was accompanied by a reduction in the total contents of carotenoid pigments and an increased sensitivity of the cell walls to snail gut enzymes (Helix pomatia) as judged by spheroplast formation. Walls isolated from supplemented cultures contained increased amounts of lipid and mannan but had a reduced content of protein and alkali-insoluble carbohydrate. The chemical modifications of the cell wall, which resulted as an indirect consequence of excessiveS-adenosylmethionine synthesis, are interpreted to explain the ease with which sulfur amino acid-supplemented cultures ofR.aurantiacaare converted to spheroplasts as well as their tendency to aggregate.

ISSN:0008-4166    

DOI:10.1139/m72-066

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Strains U9(pase,tet,ery,nov)and U9(pase,tet,ol,nov) ofStaphylococcus aureuswere used as donors of theeryandolmarkers, respectively, to strain 152. Thirty-three erythromycin-sensitive (ery-s) mutants of strain 152(ery) and 19 oleandomycin-sensitive (ol-s) mutants of strain 152(ol) were isolated following diethyl sulfate mutagenesis. The results of reciprocal transductions involving these mutants are as follows: (a) the frequency at which theeryandolmarkers were transduced into each mutant varied greatly, and was especially low in those mutants which yielded recombinants in reciprocal transductions between the mutants; (b) 13 of the 19ol-smutants yielded recombinants in reciprocal transductions between theol-smutants; (c) no recombinants were detected in reciprocal transductions betweenery-smutants; (d) antibiotic-resistant recombinants were obtained in reciprocal transductions between threeery-smutants and threeol-smutants. The results of this study demonstrate that there is only one genetic locus which controls resistance to erythromycin and oleandomycin in these strains, and that it exists in an inducible state (theerymarker) and a constitutive state (theolmarker).

ISSN:0008-4166    

DOI:10.1139/m72-067

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The replication of simian adenovirus (SV15) in green-monkey kidney cells (GMK) and hamster embryo cells (HE) was compared. In addition, the ability of these virus-cell systems to enhance the growth of adenovirus-associated virus type 1 (AAV-1) was studied. Simian virus 15 infectious progeny was undetectable from infected HE cells even though the cell monolayer was destroyed by viral cytopathology (CPE) similar to that observed in GMK cell cultures. Also, when SV15 was serially passed in HE cells, infectivity was undetectable after two passages. Serological analysis by complement fixation and immunofluorescent staining indicated that some SV15 antigens, which were unrelated to the viral capsid antigens, were produced in HE cell cultures. These antigens were presumably the early antigens found in adenovirus infections.Simian virus 15 productively infected GMK cells and also abortive infected HE cells were capable of enhancing AAV-1 growth. However, other known adenovirus abortive infections, e.g., adenovirus type 2 or 7 infected GMK cells, adenovirus type 12 infected or transformed HE cells, did not display "helper" activity for AAV-1 replication. The results indicate that the termination of adenovirus growth in an abortive type of infection occurs at different stages in the replication cycle, which is apparently dependent upon the virus-cell system.

ISSN:0008-4166    

DOI:10.1139/m72-068

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Cytoplasm preparations obtained from 42 non-photochromogenic strains of mycobacteria were examined with the cytoplasm antisera by a cellulose-acetate immunodiffusion test. Seven cytoplasm serogroups of these mycobacteria were distinguished by the presence or absence of the characteristic, major antigenic determinants; and immunological relationships existing between the different species were described.

ISSN:0008-4166    

DOI:10.1139/m72-069

出版商:NRC Research Press    

年代:1972

数据来源: NRC