摘要:

The relative persistence capacity in mouse spleen of 10 and 9 BCG substrains from liquid and dried vaccines, respectively, was evaluated in two studies. Recoverable BCG colony counts from mouse spleen were determined at given days on solid medium in the two studies during a period of 1–360 and 1–345 days, respectively, after the intravenous BCG vaccination, performed with two different viable units. From 36 000 (study 1) and 21 600 (study 2) recoverable BCG colony counts, 180 and 108 mean relative persistence capacity values were estimated to test the residual virulence during the follow-up time, using computerized statistical analysis. The early and late trends of mean relative persistence capacity of the BCG substrains in mouse spleen were tested by linear regression analysis and analysis of variance and covariance; then with ranked adjusted group mean relative persistence capacity, Gabriel's simultaneous test procedure was performed for multiple comparison to diminish type 1 error in statistical inference and in objective interpretation of the experimental results. The associations of the ranked mean relative persistence capacity of the BCG substrains at the different sacrifice days of mice were also analyzed by Kendall's test of concordance. The early, late, and overall relative persistence capacity reflects the residual virulence of the BCG substrains and provides information on the required protective efficacy (immunogenicity) and adverse reactions (reactogenicity), allowing the appropriate vaccination dose, expressed in viable units of the substrain used, to be determined.Key words: BCG substrains, residual virulence, relative persistence in mouse spleen, multiple comparison.

ISSN:0008-4166    

DOI:10.1139/m92-029

出版商:NRC Research Press    

年代:1992

数据来源: NRC

摘要:

Root nodules obtained fromTrevoa trinervisand its actinomyceteFrankiawere studied by electron microscopy. The microsymbiont was found in the cortical cells and it exhibits the typical actinomycetal structures: septate hyphae and symbiotic vesicles. Using the double-layer technique, twoFrankiastrains were isolated from the nodules.In vitrothese strains exhibit morphological characteristics considered specific to the genusFrankia, i.e., hyphae,Frankiavesicles, and polymorphic sporangia.Key words:Frankia, actinomycetes,Trevoa.

ISSN:0008-4166    

DOI:10.1139/m92-030

出版商:NRC Research Press    

年代:1992

数据来源: NRC

摘要:

A mixed culture of two fast-growing bacterial strains for heavy-metal solubilization of municipal sewage sludge has been developed. Strain VA-7 decreases the initial sludge pH (7–8.5) to a value between 4.0 and 4.5. Then, strain VA-4 begins growing and further reduces the pH to values below 2.0. The rapid decrease of sludge pH by a mixed culture through sulfur oxidation into sulfuric acid solubilizes the toxic metals (Cd 83–96%, Cr 16–54%, Cu 85–87%, Mn 91–94%, Ni 78–79%, Pb 28–46%, Zn 82–96%) to levels recommended for intensive use of residual sludge in agriculture. A study of the physiological and metabolic characteristics of these strains revealed that isolate VA-7 is a strain ofThiobacillus thioparus(ATCC 55127), while isolate VA-4 corresponds to aThiobacillus thiooxidans(ATCC 55128). These bacterial strains possess distinctive physiological characteristics that allow them to easily grow and solubilize heavy metals in municipal sludge.Key words: heavy metals, sewage sludge, thiobacilli, bioleaching, elemental sulfur.

ISSN:0008-4166    

DOI:10.1139/m92-031

出版商:NRC Research Press    

年代:1992

数据来源: NRC

摘要:

Previously it was reported that influenza virus stimulated, nonspecific resistance was largely due to its glycoproteins, hemagglutinin (HA) and neuraminidase (NA). The enhancement of natural killer cell activity was the intrinsic property of NA and HA. In the present study, the stimulatory effect of these glycoproteins on the murine peritoneal macrophages was studied. Electrophoretically purified glycoproteins, NA and HA, of influenza virus A/USSR/90/77 (H1N1) were administered intraperitoneally to C3H/HeN mice, with or without stearyl tyrosine (ST). Macrophages were isolated and were restimulated with phorbol myristate acetate. H2O2secretion was determined by horseradish peroxidase dependent oxidation of phenol red assay. HA enhanced H2O2secretion only in the presence of ST (60 nmol∙mg−1∙h−1), whereas NA alone stimulated H2O2secretion (83 nmol∙mg−1∙h−1), by 6-fold over control (13 nmol∙mg−1∙h−1), and this stimulation was further increased (136 nmol∙mg−1∙h−1) in the presence of ST. Interleukin 1 (IL-1) activity was determined by using D10.G4.1 cells. There was a little stimulation of IL-1 activity (<1 U/mL) of macrophages isolated from HA-primed or HA+ST-primed mice restimulated with HA. On the other hand, IL-1 activity of macrophages isolated from NA-primed mice restimulated with NA significantly increased (102 U/mL) over control (<1 U/mL), and an additional 2-fold increase (231 U/mL) resulted when macrophages from NA + ST-primed mice were used. Tumor necrosis factor (TNF) activity was examined by using L929 cells. Negligible TNF activity was observed in macrophages isolated from either HA-primed or HA + ST-primed mice restimulated with HA. Macrophages from NA-primed mice restimulated with NA increased TNF activity from 2.1 (control) to 20 U/mL, and this activity increased further to 536 U/mL in macrophages from NA + ST-primed mice. NA of N2 subtype also possessed the potential to stimulate TNF activity. ST had an enhancing effect on the stimulatory potential of proteins. Our present results supported by our earlier findings show that NA, even though enzymatically inactive, can stimulate nonspecific resistance mechanisms and probably plays an important role in the control of early influenza infection.Key words: influenza, glycoproteins, modulati

ISSN:0008-4166    

DOI:10.1139/m92-032

出版商:NRC Research Press    

年代:1992

数据来源: NRC

摘要:

The entire nucleotide sequence of thersaAgene, encoding the paracrystalline surface (S) layer protein (RsaA) ofCaulobacter crescentusCB15A, was determined. ThersaAgene encoded a protein of 1026 amino acids, with a predicted molecular weight of 98 132. Protease cleavage of mature RsaA protein and amino acid sequencing of retrievable peptides yielded two peptides: one aligned with a region approximately two-thirds the way into the predicted amino acid sequence and the second peptide corresponded to the predicted carboxy terminus. Thus, no cleavage processing of the carboxy portion of the RsaA protein occurred during export, and with the exception of the removal of the initial methionine residue, the protein was not processed by cleavage to produce the mature protein. The predicted RsaA amino acid profile was unusual, with small neutral residues predominating. Excepting aspartate, charged amino acids were in relatively low proportion, resulting in an especially acidic protein, with a predicted pI of 3.46. As with most other sequenced S-layer proteins, RsaA contained no cysteine residues. A homology scan of the Swiss Protein Bank 17 produced no close matches to the predicted RsaA sequence. However, RsaA protein shared measurable homology with some exported proteins of other bacteria, including the hemolysins. Of particular interest was a specific region of the RsaA protein that was homologous to the repeat regions of glycine and aspartate residues found in several proteases and hemolysins. These repeats are implicated in the binding of calcium for proper structure and biological activity of these proteins. Those present in the RsaA protein may perform a similar function, since S-layer assembly and surface attachment requires calcium. RsaA protein also shared some homology with 10 other S-layer proteins, with theCampylobacter fetusS-layer protein scoring highest.Key words:Caulobacter crescentus, surface layer, nucleotide sequence,rsaA, calcium.

ISSN:0008-4166    

DOI:10.1139/m92-033

出版商:NRC Research Press    

年代:1992

数据来源: NRC

摘要:

Biodegradation of soil humic acids byStreptomyces viridosporusATCC 39115 growing in a mineral salts – glucose medium was demonstrated. This biodegradation accompanies bacterial growth and is, therefore, presumed to be a primary metabolic activity, but humic acids were not used as the sole source of carbon. This bacterial activity was enhanced when cells were shaken and within a pH range of 6.5–8.5. In further experiments, the relative abilities ofS.viridosporusto mineralize [14C]melanoidin, used as synthetic humic acid, were also established. In contrast to the white rot fungusPhanerochaete chrysosporium, another microorganism exhibiting humic acid degrading activity at acidic pH, poor extracellular activities were found in culture medium ofS.viridosporus, and veratryl alcohol does not result in increased humic acid degradation. In spite of some peroxidase activity measured in culture filtrates and analyzed by polyacrylamide gel electrophoresis, the humic acid degrading system ofS.viridosporus, in these experimental conditions, seems to be cell associated.Key words: humic acid biodegradation, melanoidin mineralization,Streptomyces viridosporus, cell-bound humic acids.

ISSN:0008-4166    

DOI:10.1139/m92-034

出版商:NRC Research Press    

年代:1992

数据来源: NRC

摘要:

Conidia and mycelial cells ofFonsecaea pedrosoiATCC 46428 were obtained for analyses of lipid composition. Total lipids, phospholipids, sterols, and qualitative sterols and fatty acid composition were determined. A higher lipid content was detected in conidia than in mycelial cells ofFonsecaea pedrosoi, which could not be attributed to total sterols and phospholipids. In both forms of this fungus, ergosterol was the only sterol detected. The minimal inhibitory concentration of amphotericin B was lower for conidia than for mycelium.Key words:Fonsecaea pedrosoi, chromoblastomycosis, sterol, amphotericin B, lipid composition.

ISSN:0008-4166    

DOI:10.1139/m92-035

出版商:NRC Research Press    

年代:1992

数据来源: NRC

摘要:

One hundred strains ofClostridium perfringensand 52 strains of other Clostridia of human and animal origins were screened for tetracycline resistance. Fifty-six strains were resistant to tetracycline in theC.perfringensgroup. Ten strains were selected for their high level of resistance. In all of them, the tetracycline-resistance genes were found to be residing in large plasmids of about 50 kb, all showing homologies. Several tetracycline-resistance genes from plasmids of various strains ofC.perfringenswere cloned in plasmid pUC19 and the resistance was expressed inEscherichia coli. Hybridization analysis showed these genes to be homologous among themselves and also totetPgene from the PCW3-type plasmid.Key words: tetracycline resistance,Clostridium perfringens, gene cloning, recombinant plasmids.

ISSN:0008-4166    

DOI:10.1139/m92-036

出版商:NRC Research Press    

年代:1992

数据来源: NRC

摘要:

This article deals with the culture of grass carp (Ctenopharyngodon idellus) lip and embryo cells on Cytodex 3 and GT-2 microcarriers in a 1.5-L cell culture bioreactor to propagate grass carp hemorrhage virus. The cells and viruses were successfully cultivated at 26 °C, pH 7.0, and dissolved oxygen 40% of air saturation. The cell density achievedwas as high as 7.4 × 106 cells/mL, and the virus titre reached 6.75 log LD50/0.5 mL from an initial 3.00 log LD50/0.5 mL. The results present broad prospects for fish virus vaccine production.Key words: fish cell, hemorrhage virus, microcarrier, cell culture.

ISSN:0008-4166    

DOI:10.1139/m92-037

出版商:NRC Research Press    

年代:1992

数据来源: NRC

摘要:

Over a period of 14 years (1973–1987), 3165 specimens submitted to the microbiology laboratory demonstrated the recovery of anaerobic bacteria. A total of 988Bacteroides fragilisgroup isolates were recovered (0.3 isolates per specimen).Bacteroides fragilisaccounted for 62% of the total of allB.fragilisgroup isolates,Bacteroides thetaiotaomicronfor 15%,Bacteroides vulgatusfor 8%,Bacteroides ovatusfor 7%,Bacteroides distasonisfor 6%, andBacteroides uniformisfor 2%. Of the 988B.fragilisgroup isolates, 310 (31%) were recovered after the administration of antimicrobial therapy, and 129 (13%) were the single isolate recovered from the infected site at that time. The recovery rate of all members ofB.fragilisgroup after the administration of antimicrobial therapy, when isolated alone or when mixed with other bacteria, was similar. The data illustrate the equal ability of all members of theB.fragilisgroup to persist in and to contribute to the inflammatory process; and provide further support for their pathogenic role.Key words:Bacteroides fragilis, bacteremia, abscesses, antimicrobials.

ISSN:0008-4166    

DOI:10.1139/m92-038

出版商:NRC Research Press    

年代:1992

数据来源: NRC