摘要:

The ability of a variety of soluble factors, alone or in combination, to endow murine resident peritoneal macrophages with listericidal activity was assessed. Inhibition of growth and (or) killing ofListeriain infected macrophages was determined by the uptake of [3H]uracil following lysis of the infected macrophage monolayers. Interferon-γ was shown to induce modest listericidal activity in murine resident macrophages as compared with untreated monolayers. Treatment with tumour necrosis factor alpha also induced significant listericidal activity in this system. Among other cytokines tested, IL-4 induced an ability to inhibit growth ofListeriain resident macrophages. The ability of cytokines to act in an additive or synergistic fashion with IFN-γ was also investigated. Combinations of IFN-γ and IL-4 and IFN-γ and IL-2 induced listericidal activity not greater than that seen with IFN-γ alone. IFN-γ and TNF-α were shown to increase bactericidal activity in an additive fashion. However, elicited macrophages were shown to spontaneously exert a significant listericidal activity that was not enhanced by cytokine treatment. Collectively, these findings show that cytokine treatment induced rather modest enhancement in listericidal activity in murine resident peritoneal macrophages and no enhancement whatsoever in elicited macrophages. Thus, inin vivosituations whereListeriaorganisms are completely cleared from the infected organs, mechanisms other than lymphokine-induced listericidal activity of resident macrophages would seem to be operating.Key words:Listeria, macrophages, cytokines.

ISSN:0008-4166    

DOI:10.1139/m90-114

出版商:NRC Research Press    

年代:1990

数据来源: NRC

摘要:

Two bacterial strains were isolated from a bacterial community formed of nine strains, selected from a marine sediment on a seawater medium with naphthalene as sole carbon source. The two strains studied in the present work were the only strains of this community able to grow in pure culture on naphthalene; therefore, they were called "primary" strains. The seven other strains were maintained in the community by using metabolic intermediates of the two primary strains; they were called "auxiliary" strains. Regulation of naphthalene metabolism was studied for the two primary strains. They oxidized naphthalene into catechol, which was degraded only by themetapathway. ForPseudomonasLav. 4, naphthalene oxygenase and salicylate hydroxylase were inducible; catechol 2,3-dioxygenase was constitutive. ForMoraxellaLav. 7, naphthalene oxygenase was constitutive; salicylate hydroxylase and catechol 2,3-oxygenase were inducible. TheMoraxellastrain carries two cryptic plasmids, about 63-and 85-kb in molecular size. In the bacterial community culture medium,MoraxellaLav. 7 prevented accumulation of 2-hydroxymuconate semialdehyde formed byPseudomonasLav. 4. The auxiliary strains take up formic, acetic, pyruvic, propionic, and succinic acids released by the two primary strains.Key words: marine bacterial community, naphthalene metabolism.

ISSN:0008-4166    

DOI:10.1139/m90-115

出版商:NRC Research Press    

年代:1990

数据来源: NRC

摘要:

Analyses of ergosterol and activities of arginine decarboxylase (ADC) and ornithine decarboxylase (ODC) were used as estimates of fungal mass and metabolic activity, respectively, in aerial mycelia ofHebeloma crustuliniforme(Bull.: St. Amans) Quel. Omission of inorganic P from the medium decreased the ergosterol concentration of perimeter mycelia by 15–30% and increased ADC and ODC activities up to 6-fold. The magnitude of changes with omission of glucose C were similar but the trend was reversed. Ergosterol content and enzyme activities differed among colony locations; perimeter mycelia contained up to 1.8 times more ergosterol and up to 3.6 times more ADC and ODC activity per gram than mycelia at the core. Ergosterol mass and colony mass were positively correlated; the equationY = −5.46 + 0.38(X), whereY= mycelia mass (mg) andX= ergosterol mass (μg), accounted for 77% of the variance in colony mass. The ratio of ODC:ADC activity was 21 at the perimeter and 30 at the core; activity ratios may be used to infer maturation state of a fungal colony. Potential application of ergosterol content and activities of ADC and ODC as biochemical indices in mycological research is discussed.Key words: arginine decarboxylase, colony development, ergosterol,Hebeloma, ornithine decarboxylase.

ISSN:0008-4166    

DOI:10.1139/m90-116

出版商:NRC Research Press    

年代:1990

数据来源: NRC

摘要:

The array ofBacteroides gingivalisW83 antigens revealed by crossed Immunoelectrophoresis includes one antigen that is associated with an erythrocyte-binding capacity, termed the hemagglutinating adhesin HA-Ag2. This antigen was excised from crossed-immunoelectrophoresis plates to produce two polyclonal antisera, VL 011 and WL 303, whose restricted specificity for HA-Ag2 was assessed using crossed Immunoelectrophoresis, crossed Immunoelectrophoresis with an intermediate gel, and crossed imunoaffinoelectrophoresis. Both antisera, when used to probe blots of an EDTA cell surface extract ofB.gingivalisW83, reacted with two bands, at 33 and 38 kDa, which were also detected by a monoclonal antibody (Naito et al. 1985. Infect. Immun. 50:231–235), specific for a hemagglutinin ofB.gingivalis. Antiserum WL 303 was used to examine by immunoblotting the distribution of HA-Ag2 among a variety of human and animal strains ofB.gingivalis. All human strains tested showed two major bands at 33 and 38 kDa in the EDTA cell surface extract, and at 43 and 49 kDa in outer membrane preparations. Only one band, at 29 kDa, was detected in EDTA cell surface extracts from the animal strains, while the outer membrane preparation of a single strain showed a positive reaction. We concluded that HA-Ag2 is an antigen common to human and animal strains ofB.gingivalisand that its subunits may show heterogeneity in apparent molecular mass.Key words:Bacteroides, EDTA extract, outer membranes, crossed immunoelectrophoresis, immunoblot.

ISSN:0008-4166    

DOI:10.1139/m90-117

出版商:NRC Research Press    

年代:1990

数据来源: NRC

摘要:

Several strains ofListeriaspecies formed petite-sized colonies from parent stock cultures when grown on agar media containing 0.2 – 1% (w/v) esculin. This was observed inListeria monocytogenes(7/22 strains),L.innocua(1/3),L.grayi(1/1),L.seeligeri(1/3), andL.welshimeri(1/1), but not inL.ivanovii(0/1) andL.murrayi(0/1). This phenomenon was only observed on agar media that contained esculin. All petite isolates had biotyping profiles identical to their larger, normal-sized counterpart isolates. Normal and petite-sized isolates from twoL.monocytogenesstrains, Scott A and V7, were pathogenic to immunosuppressed white mice. On media containing 0.5% (w/v) esculin + ferric iron,Listeriacultures produced colony diameters intermediate in size between those of normal and petite cultures. When pregrown in glucose broth, all petite isolates demonstrated visible β-glucosidase (esculinase) activity within 5 min, while the normal-sized isolates showed β-glucosidase activity only after at least 20–70 min. This evidence suggests that cells forming petite colonies are β-glucosidase constitutive variants within the parent population, while cells that form normal-sized colonies are inducible for β-glucosidase (esculinase) activity. A possible role for the esculin hydrolysis product, esculetin, in causing petite colony formation is discussed.Key words:Listeriaspecies, petite colonies, esculinase, pathogenicity.

ISSN:0008-4166    

DOI:10.1139/m90-118

出版商:NRC Research Press    

年代:1990

数据来源: NRC

摘要:

The accumulation of radioactive Cs by fungi was studied by analysis of fruit bodies (n(total) = 205,n ≥ 5 for 22 species) collected in 1988 in a Norwegian mountain area with high deposition of radiocaesium from the Chernobyl accident. To account for site variation, the radiocaesium content of soil and plants was determined for each sampling spot. The soil contained 5–600 kBq/m2(median = 50 kbq/m2,134Cs +137Cs). The plant content ranged from 0.25 to 23 Bq/g dry weight (median = 3.1 Bq/g) and was positively correlated with radiocaesium concentration in the soil (r = 0.56) and negatively correlated with soil pH (r = −0.28). The ratio between radiocaesium content in fungi and that in plants at the same spot (F/P) differed among species: 25 species hadF/Pvalues between 30 and 270, 12 species hadF/Pvalues between 10 and 30, and the rest (16 species) hadF/Pvalues below 10 (only four samples had values below 1). The concentration of nonradioactive Cs in fruit bodies was positively correlated with their radiocaesium content. Certain species selectively accumulated one or several trace elements (V, Cd, Hg, Pb, Th).Key words: radioactivity, caesium, fungi, plants, soil.

ISSN:0008-4166    

DOI:10.1139/m90-119

出版商:NRC Research Press    

年代:1990

数据来源: NRC

摘要:

Antibody and complement immobilize (kill)Treponema pallidumin vitro. Recent evidence also documents immobilization by soluble factors released by activated macrophages and lymphocytes. Immune-mediated lysis of treponemes, however, has not been reported. The findings in this paper focus on apparent treponemal lysis by rabbit splenic cell preparations. Using cells from animals infected testicularly for 9 to 12 days, unfractionated splenic preparations, as well as adherent and nonadherent preparations, killed and lysedT.pallidum. Phagocytosis alone could not explain the detrimental effects of adherent cells. When cytochalasin B was used to block phagocytosis, decreases in treponemal numbers were still detected. In related studies, immune rabbit sera did not enhance treponemicidal activity of the adherent cells. To assess the specificity of these reactions,T.pallidumwas incubated with two monocyte-like cell lines (human U937 and mouse P388D1). Neither cell line was detrimental, and treponemal numbers were not lowered. The soluble nature of the treponemicidal factors from adherent and nonadherent preparations was shown by physically separating these cells from the organisms and demonstrating treponemal killing and lysis. In summary, clearance ofT.pallidumfrom infected tissues is probably at least partially attributed to macrophage phagocytosis. Our findings suggest another mechanism involving lytic factors secreted by activated adherent and nonadherent cells.Key words: syphilis, splenic treponemicidal activity,Treponema pallidum.

ISSN:0008-4166    

DOI:10.1139/m90-120

出版商:NRC Research Press    

年代:1990

数据来源: NRC

摘要:

The genes encoding dibenzothiophene (DBT) degradation inPseudomonas alcaligenesstrain DBT2 were cloned into plasmid pC1 by other workers. This plasmid was conjugally transferred into a spontaneous variant ofPseudomonassp. HL7b (designated HL7bR) incapable of oxidizing DBT (Dbt−phenotype). Acquisition of plasmid pC1 simultaneously restored oxidation of DBT and naphthalene to the transconjugant, although the primary DBT metabolite produced by transconjugant HL7bR(pC1) corresponded to that produced by wild-type strain DBT2 rather than that from wild-type strain HL7b. Inducers of the naphthalene pathway (naphthalene, salicylic acid, and 2-aminobenzoate) stimulated DBT oxidation in transconjugant HL7bR(pC1) when present at 0.1 mM concentrations but had no effect on wild-type strain HL7b. Higher concentrations (5 mM) of salicylic acid and naphthalene were inhibitory to DBT oxidation in all strains. DNA–DNA hybridization was not observed between plasmid pC1 and genomic DNA from strains HL7b or HL7bR, nor between authentic naphthalene-degradative genes (plasmid NAH2) and either plasmid pC1 or strain HL7b, despite the observation that the degradative genes encoded on plasmid pC1 functionally resembled broad-specificity naphthalene-degradative genes. Transconjugant HL7bR(pC1) is a mosaic of the parental types regarding DBT metabolite production, regulation, and use of carbon sources.Key words: dibenzothiophene, naphthalene, degradation, regulation, hybridization.

ISSN:0008-4166    

DOI:10.1139/m90-121

出版商:NRC Research Press    

年代:1990

数据来源: NRC

摘要:

7α-Hydroxysteroid dehydrogenase (EC 1.1.1.159) production byEscherichia colistrain 080 was highest when the organism was grown in brain heart infusion broth at pH 6.5 for 72–96 h with shaking at 37 °C. The oxygen consumption rate had a strong effect on the production of this constitutive enzyme. Glucose and lactose at 0.2–0.4%, detergents, and ethylenediaminetetraacetic acid were found to increase the enzyme production.Key words: 7α-hydroxysteroid dehydrogenase,Escherichia coli080, optimal conditions for 7α-hydroxysteroid dehydrogenase production.

ISSN:0008-4166    

DOI:10.1139/m90-122

出版商:NRC Research Press    

年代:1990

数据来源: NRC

摘要:

Catalase activities in crude extracts of exponential and stationary phase cultures of various bacteria were visualized following gel electrophoresis for comparison with the enzymes fromEscherichia coli.Citrobacter freundii,Edwardsiella tarda,Enterobacter aerogenes,Klebsiella pneumoniae, andSalmonella typhimuriumexhibited patterns of catalase activity similar toE.coli, including bifunctional HPI-like bands and a monofunctional HPII-like band.Proteus mirabilis,Erwinia carotovora, andSerratia marcescenscontained a single band of monofunctional catalase with a mobility intermediate between the HPI-like and HPII-like bands. The cloned genes for catalases HPI (katG) and HPII (katE) fromE.coliwere used as probes in Southern hybridization analyses for homologous sequences in genomic DNA of the same bacteria.katGwas found to hybridize with fragments fromC.freundii,Ent.aerogenes,Sal.typhimurium, andK.pneumoniaebut not at all withEd.tarda,P.mirabilis,S.marcesens, orEr.carotovora.katEhydridized withC.freundiiandK.pneumoniaeDNAs and not with the other bacterial DNAs.Key words: catalase genes, bacteria, homology.

ISSN:0008-4166    

DOI:10.1139/m90-123

出版商:NRC Research Press    

年代:1990

数据来源: NRC