ISSN:0008-4166    

DOI:10.1139/m79-096

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Thymidine is rapidly catabolized to thymine, β-aminoisobutyric acid, and carbon dioxide byRhizobium meliloticells. The incorporation of labelled thymidine into the DNA ofR.meliloticells can be enhanced by the addition of low concentrations (10–20β μg/mL) of deoxyadenosine or other nucleosides (adenosine, uridine, guanosine). However, at high concentrations (>50 μg/mL) these compounds inhibit thymidine incorporation. Conditions to obtain highly radioactive DNA ofRhizobiumare described.

ISSN:0008-4166    

DOI:10.1139/m79-097

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

A Vero cell adapted Green strain of canine distemper virus (CDV) was tested for its plaque-forming capacity in different cell lines. Plaque formation was observed in HEp-2, BS-C-I, and HeLa cells but not in Vero or dog kidney cells even though replication and cytopathology were observed in the latter cell types. In the cells in which the virus was capable of producing plaques, the plaques were observed within 24 h post infection and continued to increase in size with subsequent cellular destruction such that by 72 h postinfection the size of the plaques approached 0.5 mm. With the use of the plaquing technique, it was possible to demonstrate the thermal lability of the virus as well as the kinetics of adsorption. Thus, it was shown that the half-life of the virus was 125 min at 25 °C, 75 min at 35 °C, and 65 min at 37 °C. The rate of adsorption of CDV to HEp-2 cells was 17.2% in 30 min at 37 °C and continued slowly for 4 h before completion. Application of this rapid plaque-forming assay to plaque-reduction tests for CDV antibody and for CDV-infected cells by the infectious center assay are described.

ISSN:0008-4166    

DOI:10.1139/m79-098

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Antibodies to staphylococcal alpha toxin were separated into two distinct populations. One population prevented binding of alpha toxin onto erythrocyte membranes. The other population neutralized after the toxin was bound onto erythrocytes and thereby brought about an indirect hemagglutination reaction.The data suggest that alpha toxin has a membrane-binding region.

ISSN:0008-4166    

DOI:10.1139/m79-099

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

We have isolatedAzospirillum(Spirillum lipoferum) from roots of grasses of several genera collected from a number of tropical and subtropical-temperate locations. Pure cultures were obtained from a small percentage of samples; no higher percentage was secured from tropical than from other grasses. Acetylene reduction and distinctive growth in N-free soft agar deeps were inadequate to identify this genus, although helpful in intial screening. Fluorescent antibody tests with antiserum against characterized strains were helpful. There is some evidence that this genus of bacteria may be favored in the rhizoplane.

ISSN:0008-4166    

DOI:10.1139/m79-100

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

A water-soluble monocytosis-producing activity (MPA) extracted fromListeria monocytogeneswas found to stimulate proliferation of promonocytesin vivo. Mice were pulse-labelled for 2 h with tritiated thymidine ([3H]TdR) at various times after intraperitoneal injection of MPA. Autoradiography of bone marrow cells revealed an increased labelling index of promonocytes of MPA-treated mice which was maximum 8 h after the MPA injection. Mice labelled with [3H]TdR 8 h after MPA injection developed a monocytosis at the expected time (peak at 48 h) and the blood monocytes were found to be highly labelled. Both the generation time of monocyte precursors and the halftime of blood monocytes were found to be shorter than the corresponding values in control mice.

ISSN:0008-4166    

DOI:10.1139/m79-101

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

A fraction rich in a monocytosis-producing activity (MPA) has been obtained by a two-stage chromatographic separation from a saline extract (SE) ofListeria monocytogenes. Like SE, the purified material elicits monocytosis and decreases the halftime of circulating monocytes. The purification of MPA eliminates the following found in SE: thein vitromitogenic activity, thein vitroadjuvant activity, the immunosuppressive activity, and the granulocytosis-promoting and the lymphopenia-inducing activities.

ISSN:0008-4166    

DOI:10.1139/m79-102

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

A DNA–DNA hybridization study was carried out on a new group of enterobacteria (group H1) previously studied by numerical taxonomy work on the genusEnterobacter. This group showed a very high genetic homogeneity since the average relative binding ratio of nine analysed strains is equal to 91%. The taxonomic position of this group into the family of enterobacteria is discussed with the speciesE.cloacae(37 to 61%),K.pneumoniae(44 to 60%),K.oxytoca(57–58%),L.malonatica(syn.Citrobacter intermedius,a: 46 to 54%),L.amalonatica(syn.C.intermedius, b: 51%), and the group H3(52–61%). The group H1is defined on phenotypic and genetic data.

ISSN:0008-4166    

DOI:10.1139/m79-103

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

During growth ofClostridium pasteurianumon sulfite, approximately half the sulfite was reduced to sulfide and half to thiosulfate. Sulfide was enriched in32S or34S at different stages of growth and thiosulfate was enriched in32S, particularly in the sulfane atom.It is suggested that thiosulfate in these bacterial cultures arose from a secondary chemical reaction. The chemical formation of thiosulfate from sulfide and sulfite was also accompanied by sulfur isotope fractionation. The implications of these results with respect to 'inverse' isotopic effects are discussed.

ISSN:0008-4166    

DOI:10.1139/m79-104

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Large numbers of minute, flat, long, straight, but often broken structures were observed in aqueous extracts of soil. We have applied the purely descriptive term 'tubules' to these structures, because they apparently became flattened during preparation for electron-microscopic viewing. The tubules appared to be composed of parallel fibers held together by protein. Most of the tubules fell within a range of 10 to 50 nm in width. Lengths (of broken pieces) ranged from 0.2 to 1 μm or more. A few unbroken ends were found. They were rounded. Tubular structures of similar dimensions were found surrounding lysed cells in sectioned preparations of bacteria that had been separated from soil. The tubules were present in surface soils but not a subsurface sample. Their numbers decreased during bacterial multiplication in soil or broth containing soil. No evidence was found of cleared areas or increase in number of tubules when the tubules were plated with a heterogeneous microbial flora from soil.

ISSN:0008-4166    

DOI:10.1139/m79-105

出版商:NRC Research Press    

年代:1979

数据来源: NRC