摘要:

Pseudomonas syringae,P.phaseolicola, andP.glycineaproduced and were sensitive to bacteriocins. Both solid and liquid media were used in the detection procedures. The bacteriocins were classified into 11 groups on the basis of activity spectra against strains of the same species, related and unrelated species, and unrelated genera. Heat, chloroform, trypsin, and pronase sensitivity were useful in subdividing some of the groups. AllP.syringaestrains produced bacteriocins, as did 55% of theP.glycineastrains and 8% of theP.phaseolicolastrains.Bacteriocins fromP.syringaehad the broadest spectrum of activity, those fromP.glycineawere more restricted in activity, and those fromP.phaseolicolahad the narrowest range of activity.Bacteriocin production was affected by agar depth, age of plates, age of culture, colony type, amount of inoculum, proximity to producers of bacteriocin inhibitors, and temperature. In many cases, detection of bacteriocin production depended on the choice of these conditions.

ISSN:0008-4166    

DOI:10.1139/m72-113

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The acetylene reduction assay was used to determine nitrogenase activity in a waterlogged soil–straw system. Nitrogenase activity was related to the number of nitrogen-fixing Clostridia. The patterns of respiration, microbial numbers, and nitrogenase activity indicated a change in the microbial activity at about the 8th day of incubation. This was attributed to the sequential use of the different straw components, with a short lag in activity between the periods of maximum hemicellulose and cellulose utilization.Two layers of microbial activity were observed in waterlogged soil–straw mixtures, an aerobic layer extending from the surface to a depth of 2 mm, and an anaerobic layer below this. The organisms in the aerobic layer were responsible for the partial degradation of straw and the release of metabolites; the metabolites were used by the nitrogen-fixing organisms in the anaerobic layer.Anaerobic organisms of the genusClostridiumwere found to be the only active nitrogen fixers in the waterlogged systems. The physiological and morphological characteristics of the organisms isolated from the waterlogged soil are similar to those ofC.butylicum.

ISSN:0008-4166    

DOI:10.1139/m72-114

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The antiviral activity of interferon was found to be related to the amount of interferon that became cell-associated. Reduction in the amount of interferon uptake by cells by sulfhydryl-binding compounds (p-chloromercuribenzoate andN-ethylmaleimide) reduced the level of antiviral activity of the cells. Interferon, inactivated by heat or trypsin did not affect the ability of active interferon to induce an interferon uptake system. Trypsin-inactivated interferon was, however, shown to compete with active interferon for the interferon uptake system while heat-inactivated interferon was without effect.

ISSN:0008-4166    

DOI:10.1139/m72-115

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Cytoplasm preparations were obtained from 30 different strains of typical or Runyon's group I mycobacteria. Immunological activities of the cytoplasms were examined with immune globulins of cytoplasm antisera by an immunodiffusion test on cellulose–acetate membranes. Patterns of immunological activity of the cytoplasms were found to be relatively simple. Six different serogroups of the mycobacteria have been distinguished by the presence of one or two characteristic antigenic factors in the cytoplasm. The cytoplasm serogroups correlated with the cultural types and species designations. The serogroup and serotype chart was recommended for immunological identification and differentiation of the typical and group I mycobacteria.

ISSN:0008-4166    

DOI:10.1139/m72-116

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The sulfur metabolism ofThiobacillus ferrooxidans,Ferrobacillus ferrooxidans, andFerrobacillus sulfooxidanswas found to differ in the rate of utilization of thiosulfate and tetrathionate, with tetrathionate showing the most significant difference between the three organisms. The apparentKmvalues of the three organisms ranged from 2–5 × 10−2 MforT.ferrooxidansandF.sulfooxidansto 5–7 × 10−3 MforF.ferrooxidans. Increasing the temperature caused a greater effect on thiosulfate oxidation byF.ferrooxidansthan with the other two as shown by the apparentEavalues (Ea′ forF.ferrooxidans, 18 000;F.sulfooxidans, 11 400;T.ferrooxidans, 11 000).The initial pH of the medium determined the rate of thiosulfate oxidation. If the initial pH was 4.0–4.5, a sharp break in oxygen uptake was shown byT.ferrooxidansandF.sulfooxidansafter 20–30 min, but not withF.ferrooxidans.When the disappearance of thiosulfate and tetrathionate from the medium was used as an indicator of the affinity of the three test organisms for the sulfur compounds,F.ferrooxidansdemonstrated the highest net loss of both compounds from the medium.

ISSN:0008-4166    

DOI:10.1139/m72-117

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

After intrathoracic injection of 3.2 dex Bunyamwera (BUN) virus into groups of wild caughtAedes vexansandA.canadensis, increments of infectivity were first detected in salivary glands and gut at 3 days and maximum titers of 5.2 dex per organ were attained in the salivary glands at 10 days. Virus transmission by mosquito bite was demonstrated in suckling mice 10 days after the mosquitoes were injected, but not after shorter intervals. Virus replication was not demonstrable after the ingestion of 4.0 dex in a blood meal.Aedes aegyptimosquitoes readily supported the replication of BUN virus following injection with 3.3 dex or imbibing of 4.6 dex. After injection virus titers of whole mosquitoes declined to 1.7 dex at 12 h, followed by a peak of 5.2 dex at 4 days. After feeding, virus was first detected in the hemolymph and salivary glands at 4 days and attained maximum titers of 5.0 dex in salivary glands at 10 days. Transmission of virus to mice was accomplished 10 days after feeding, but not earlier.Enveloped viruses with 45 nm cores and 80 to 120 nm external diameter were observed within vacuoles and lining vacuolar membranes of salivary glands and gut cells ofA.aegyptimosquitoes 10 days or more after infection with BUN virus. The dimensions and appearance of these particles correlated well with those of virions seen in chick embryo fibroblasts during the peak of the BUN virus infection cycle.

ISSN:0008-4166    

DOI:10.1139/m72-118

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The presence of 3 mMguanidine between the 2nd and 4th h of the poliovirus growth cycle results in a 4-h delay in viral growth, rather than the anticipated 2-h delay. For the first 90 min after removing guanidine the rate of synthesis of viral RNA is the same at both 35C and 39C. This is characteristic of the first 2 h of standard infection and suggests that a second latent period occurs after removal of inhibitor. However, the second latent period is not completely new because infective centers are very resistant to uv. light immediately after guanidine treatment. This shows that viral products synthesized during the initial latent period are used following guanidine treatment. The use of products that were formed before guanidine treatment can account for the accelerated rates of synthesis of viral RNA, viral polymerase, and viral protein that were also observed.

ISSN:0008-4166    

DOI:10.1139/m72-119

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Thirty percent of 325 sera from Athapaskan Indians in five villages in east-central Alaska were found to be positive for antibodies of California encephalitis virus (CEV) by means of the hemagglutination-inhibition (HI) test, using CEV prototype strain 283 for hemagglutination (HA) preparation. Neutralizing antibodies were detected in 72% of the sera by means of a plaque reduction method, using CEV Jamestown Canyon strain 2235. In these tests, CEV-neutralizing substances were present in all but 1 of 94 persons tested over age 30. The serum of the single exceptional individual was positive in the HI test. Since most of the persons tested had not traveled outside Alaska, serological evidence indicates that exposure to CEV had occurred within the state. Evidence for the occurrence of arboviruses in Alaska has not been reported previously.

ISSN:0008-4166    

DOI:10.1139/m72-120

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Analysis of 390 sediment samples from the Gulf of St. Lawrence and the lower reaches of the St. Lawrence River showedC.botulinumtype E to be present in high incidence in some areas while it appeared to be absent from others. No other types ofC.botulinumwere encountered. The observed distribution of type E could be correlated with patterns of terrigenous sedimentation in the region.

ISSN:0008-4166    

DOI:10.1139/m72-121

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Long-term tissue cultures derived from the TA3 ascites tumor of the mouse became nontransplantable but induced a high degree of immunoprotection against challenge with as many as 106virulent cells. Intraperitoneal immunization proved more effective than the intravenous or intramuscular routes. After chemical and physical treatments virulent TA3 cells showed no immunoprotective capacity. After similar treatments the nontumorigenic TA3 tissue-culture cells showed a moderate immunoprotective capacity. Nontumorigenic cells of the 6C3HED and TA3 lines induced a high degree of immunoprotection against solid tumor development produced by the subcutaneous injection of as many as 107virulent cells. Protection against solid tumor development could be demonstrated provided immunization with nontumorigenic cells was begun within 2 weeks of implantation of the virulent cells.

ISSN:0008-4166    

DOI:10.1139/m72-122

出版商:NRC Research Press    

年代:1972

数据来源: NRC