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Showing papers in "Canadian Journal of Microbiology in 1987"


Journal ArticleDOI
TL;DR: Inoculation of canola seeds with a nitrogen-fixing strain of Pseudomonas putida drastically increased the root length of seedlings grown in sterile growth pouches and added phosphate to the growth solution at similar concentrations stimulated root elongation of inoculated and noninoculated seedlings.
Abstract: Inoculation of canola (Brassica campestris) seeds with a nitrogen-fixing strain of Pseudomonas putida (GR12-2) drastically increased the root length of seedlings grown in sterile growth pouches. Se...

351 citations



Journal ArticleDOI
TL;DR: The killer phenomenon of yeasts was investigated in naturally occurring yeast communities and genetic study of the killer yeast P. kluyveri indicates that the mode of inheritance of killer toxin production is nuclear and not cytoplasmic as is found in Saccharomyces cerevisiae and Kluyveromyces lactis.
Abstract: The killer phenomenon of yeasts was investigated in naturally occurring yeast communities. Yeast species from communities associated with the decaying stems and fruits of cactus and the slime fluxe...

172 citations


Journal ArticleDOI
TL;DR: The bacteria and actinomycetes associated with pot cultures of the vesicular–arbuscular (VA) mycorrhizal fungi Glomus fasciculatum, Gigaspora margarita, Acaulospora laevis, Sclerocystis dussii, and of a control without VA mycor rhizal fungus were studied.
Abstract: The bacteria and actinomycetes associated with pot cultures of the vesicular–arbuscular (VA) mycorrhizal fungi Glomus fasciculatum, Gigaspora margarita, Acaulospora laevis, Sclerocystis dussii, and...

164 citations


Journal ArticleDOI
TL;DR: Results show that cellulolytic bacteria interact with noncellulolytic Treponema to promote the digestion of cellulosic materials.
Abstract: To assess the contribution of individual bacterial species to the overall process of cellulose digestion in the rumen, cellulolytic bacteria (Bacteroides succinogenes and Ruminococcus albus) were tested as pure cultures and as cocultures with noncellulolytic Treponema bryantii. In studies of in vitro barley straw digestion, Treponema cocultures surpassed pure cultures of the cellulolytic organisms in dry matter disappearance, volatile fatty acid generation, and in the production of succinic acid, lactic acid, and ethanol. Morphological examination, by electron microscopy, showed that cells of T. bryantii associate with the plant cell wall materials in straw, but that cellulose digestion occurs only when these organisms are present with cellulolytic species such as B. succinogenes. These results show that cellulolytic bacteria interact with noncellulolytic Treponema to promote the digestion of cellulosic materials.

158 citations


Journal ArticleDOI
TL;DR: Bacteria were consistently isolated from the root and crown xylem of symptomless field-grown alfalfa plants and the fluorescent pseudomonads were the most frequent bacteria isolated.
Abstract: Bacteria were consistently isolated from the root and crown xylem of symptomless field-grown alfalfa plants. Most of the plants tested contained more than one bacterial genus. Pseudomonas spp. accounted for 52% of the 387 isolates identified and the fluorescent pseudomonads were the most frequent bacteria isolated. About 23% of the isolates were Erwinia-like bacteria. Bacterial population ranged from 6.0 × 103 to 4.3 × 104 CFU/g of fresh xylem, and was not affected by plant age or cultivar or by the sampling locations. The surface-sterilized seeds of the cultivars Iroquois and Titan were bacteria free and only 3 and 5% of the seeds of the cultivars Apica and Saranac, respectively, contained bacteria. In a greenhouse experiment, double antibotic resistant bacteria were inoculated into the soil of artificially wounded and intact roots of alfalfa plants, and on the stubble. The highest incidence of bacteria in the root xylem occurred when the roots were wounded. The highest numbers of bacteria (CFU/g fresh w...

152 citations


Journal ArticleDOI
TL;DR: Gram-negative, aerobic bacteria capable of facultative growth using ferric ions or thiosulfate or sulfite as electron acceptors were readily isolated from oil field fluids.
Abstract: Gram-negative, aerobic bacteria capable of facultative growth using ferric ions or thiosulfate or sulfite as electron acceptors were readily isolated from oil field fluids. Morphological and bioche...

150 citations


Journal ArticleDOI
TL;DR: Electron microscopy showed that both strains of Pseudomonas putida and P. fluorescens were enrobed in fibrous glycocalyces and that these structures were involved in attachment of the cells to a solid surface and as structural matrices in the microcolony mode of growth.
Abstract: In this study, the adhesive exopolysaccharides of strains of Pseudomonas putida and P. fluorescens, both isolated from freshwater epilithic communities, were examined with regard to their chemical ...

138 citations


Journal ArticleDOI
TL;DR: The range of polysaccharide-degrading enzymes formed by three anaerobic rumen fungi (Neocallimastix patriciarum, Piromonas communis, and an unidentified isolate) was monitored following growth on seven mono-, di-, and poly- Saccharide carbohydrate substrates and their modes of action, pH optima, substrate affinities, and response to potential inhibitors were similar.
Abstract: The range of polysaccharide-degrading enzymes formed by three anaerobic rumen fungi (Neocallimastix patriciarum, Piromonas communis, and an unidentified isolate (F)) was monitored following growth ...

127 citations


Journal ArticleDOI
TL;DR: Under submerged growth in a defined medium (TKI broth), the entomopathogenic fungus, Beauveria bassiana, produced conidia; it produced only blastospores in complex media, which resembled "aerial" conidia in morphology and germination rates.
Abstract: Under submerged growth in a defined medium (TKI broth), the entomopathogenic fungus, Beauveria bassiana, produced conidia; it produced only blastospores in complex media. Production of such "submer...

123 citations


Journal ArticleDOI
TL;DR: The xylanase was purified from the culture filtrate of a thermophilic fungus Thermoascus aurantiacus C436 using a single chromatographic step on SP-Sephadex C50 and was homogeneous based on denaturing polyacrylamide and isoelectric focusing gels.
Abstract: A thermostable endo-β-D-xylanase (1,4-β-D-xylan xylanohydrolase, EC 3.2.1.8) was purified from the culture filtrate of a thermophilic fungus Thermoascus aurantiacus C436, using a single chromatogra...

Journal ArticleDOI
TL;DR: A strong protective environment was afforded to the methanogens against heavy metal toxicity in the sludge, indicating a strong protective environments was afforded the metanobacterium against heavyMetal toxicity inThe sludge.
Abstract: The effect of ammonium chloride, sodium butyrate, sodium propionate, and the heavy metals nickel, zinc, and copper on methanogenesis by pure cultures of Methanospirillum hungatei, Methanosarcina ba...

Journal ArticleDOI
TL;DR: The suggestion that bacterial attachment is necessary for the digestion of highly ordered crystalline cellulose, and that cellulolytic species differ in the nature of their attachment to this insoluble substrate and in thenature of their enzymatic attack, is supported.
Abstract: The presence of methylellulose prevents the attachment of cellulolytic rumen bacteria to cellulose fibers. The addition of methylcellulose to pure cultures of these organisms in which the cells are...

Journal ArticleDOI
TL;DR: Eighteen strains of soybean root colonizing soil bacteria were tested for interference with nodulation of soybeans grown in a field soil – perlite mix or in a soil-less p...
Abstract: Eighteen strains of soybean root colonizing soil bacteria were tested for interference with nodulation of soybeans (Glycine max (L.) Merrill) grown in a field soil – perlite mix or in a soil-less p...

Journal ArticleDOI
TL;DR: An exoglucanase, purified from a cellulase produce by the fungus Trichoderma harzianum Rifai.
Abstract: An exoglucanase, purified from a cellulase produce by the fungus Trichoderma harzianum Rifai., was successfully bound to colloidal gold and used for ultrastructural detection of intracellular cellu...

Journal ArticleDOI
TL;DR: A giant bacterium closely resembling Hyphomicrobium and a budding one similar to Pasteuria were recovered from all samples of a single spring and from some of the commercial samples.
Abstract: A quantitative study of bacterial populations in mineral water was carried out. Samples were stored at 6 and 20 °C, and the colony counts were determined on tryptone agar plates incubated at 22 and...

Journal ArticleDOI
TL;DR: The rumen fungi Neocallimastix patriciarum, Piromonas communis, and a morphologically distinct but unidentified isolate were cultivated on the polysaccharides starch, cellulose, xylan, and their principal component monosaccharide and disaccharides, and the range and specific activities of the glycoside hydrolases formed were monitored.
Abstract: The rumen fungi Neocallimastix patriciarum, Piromonas communis, and a morphologically distinct but unidentified isolate were cultivated on the polysaccharides starch, cellulose, xylan, and their pr...

Journal ArticleDOI
TL;DR: The effect of inhibiting protein glycosylation was studied in nongrowing mycelia and protoplasts of Trichoderma reesei which secreted two endoglucanases (I and II) upon addition of sophorose.
Abstract: The effect of inhibiting protein glycosylation was studied in nongrowing mycelia and protoplasts of Trichoderma reesei which secreted two endoglucanases (I and II) upon addition of sophorose. Tunicamycin (40 μg∙mL−1) inhibited incorporation of N-acetylglucosamine into secreted protein, but had no effect on secretion of total protein or endoglucanases. The secreted endoglucanases I and II exhibited relative molecular masses of 58 and 45 kilodaltons, respectively, irrespective of the presence of tunicamycin. On the other hand 2-deoxy-D-glucose inhibited the biosynthesis of extracellular as well as intracellular protein over a wide range of concentrations; at 50 μg∙mL−1, however, it inhibited the synthesis of extracellular protein more strongly. The synthesis of endoglucanases I and II was decreased accordingly under these conditions. SDS–PAGE did not reveal the secretion of endoglucanases with smaller molecular weights. When the two endoglucanases were purified and subjected to Endo H treatment or β-elimina...

Journal ArticleDOI
TL;DR: Nonpathogenic isolates of Fusarium oxysporum were obtained from surface-disinfested, symptomless cucumber roots grown in two raw (nonautoclaved) soils and effective isolate C5 reduced the infection rate at all inoculum densities of F.o.c.
Abstract: Nonpathogenic isolates of Fusarium oxysporum were obtained from surface-disinfested, symptomless cucumber roots grown in two raw (nonautoclaved) soils. These isolates were screened for pathogenicit...

Journal ArticleDOI
TL;DR: Azospirillum brasilense Cd cell concentration of 105–107 colony-forming units (cfu)/mL applied 24 h before Rhizobium, increased nodule formation in the non root hair zone, more than twofold, in pouch-grown Medicagopolymorpha and Macroptilium atropurpureum seedlings, compared with Rhzobium alone.
Abstract: Azospirillum brasilense Cd cell concentration of 105–107 colony-forming units (cfu)/mL applied 24 h before Rhizobium (106 cfu/mL), increased nodule formation in the non root hair zone, more than tw...

Journal ArticleDOI
TL;DR: Investigating the effect of glyphosate on the root-colonizing Fusarium spp.
Abstract: Glyphosate is a broad spectrum herbicide that can lead to root rot like damage on crops. This study was undertaken to investigate the effect of glyphosate on the root-colonizing Fusarium spp. The r...

Journal ArticleDOI
TL;DR: It is concluded that bromoethanesulfonate is a specific and effective inhibitor of methanogenic bacteria, even when used at this high concentration.
Abstract: The growth of a wide variety of eubacteria, three nonmethanogenic archaebacteria, and a yeast was not significantly inhibited by 25 mM bromoethanesulfonate, whereas three methanogenic bacteria were...

Journal ArticleDOI
TL;DR: Transmission electron microscopic observations on a wide range of decaying wood samples obtained from both field situations and laboratory exposure tests have confirmed bacteria to have a capacity to degrade intact highly lignified substrates including preservative-treated and naturally durable woody tissues.
Abstract: Transmission electron microscopic observations on a wide range of decaying wood samples obtained from both field situations and laboratory exposure tests have confirmed bacteria to have a capacity to degrade intact highly lignified substrates including preservative-treated and naturally durable woody tissues. Studies have shown a number of bacterial forms to be involved and have provided morphological evidence for in situ lignin degradation confirming 14C-labelled experiments with synthetic and natural lignins. A unique type of bacterial attack (tunnelling) characterized by the development of tunnels containing peculiar cross-tunnel wall secretions has been recognized. Cytochemical studies have shown the extracellular tunnel secretions to contain negatively charged constituents, while transmission electron microscopic energy-dispersive X-ray spectroscopy has shown these tunnels to bind heavy metals during decay of timbers treated with metal-containing preservatives. The tunnelling bacteria are motile nonf...

Journal ArticleDOI
TL;DR: The results illustrate the usefulness of the leaf-disk technique for monitoring the development of the VAM symbiosis and the significance of phosphorus in the soil solution.
Abstract: A greenhouse experiment was conducted to monitor the development of symbiotic interaction between the vesicular–arbuscular mycorrhizal (VAM) fungus Glomus aggregatum and Vigna unguiculata grown in ...

Journal ArticleDOI
TL;DR: The influence of low sulfide concentrations on nitrous oxide (N2O) reduction by resting cells of denitrifying Pseudomonas fluorescens was studied.
Abstract: The influence of low sulfide concentrations on nitrous oxide (N2O) reduction by resting cells of denitrifying Pseudomonas fluorescens was studied. Nitrous oxide reduction was inhibited by sulfide with an apparent Ki value of 1 μM. The inhibition was immediate and was readily alleviated by a short treatment of the cells with O2. In the absence of sulfide, addition of acetylene (0.2 kPa C2H2 or more) caused an immediate and complete inhibition of N2O reduction. However, when the sulfide concentration was higher than 2 μM, addition of C2H2 (range of 0.7–13 kPa tested) gave incomplete inhibition of the N2O reduction. Complete inhibition was in this case only obtained after prolonged exposure to the C2H2. The transition period with incomplete C2H2 blockage was shortest (about 20 min) for relatively high C2H2 applications (about 10 kPa). Incomplete C2H2 blockage was seen only when sulfide was added to the cell suspensions before C2H2. The data may relate to the low efficacy of the "acetylene blockage technique"...

Journal ArticleDOI
TL;DR: An α-L-arabinofuranosidase (EC 3.55) has been purified from the extracellular culture fluid of Clostridium acetobutylicum ATCC 824 and characterized and exhibited no activity on carboxymethylcellulose, arabinogalactan,Arabinoxylan, or oat spelt xylan.
Abstract: An α-L-arabinofuranosidase (EC 3.2.1.55) has been purified from the extracellular culture fluid of Clostridium acetobutylicum ATCC 824 and characterized. The enzyme was a single polypeptide with a molecular weight of 94 000, an isoelectric point of 8.15, and a pH optimum between pH 5.0 and 5.5. The Km and Vmax values for p-nitrophenyl-α-L-arabinofuranoside were 4.0 mM and 36.4 μmol∙min−1·mg protein−1, respectively. The enzyme had practically no activity against other p-nitrophenylglycosides with the exception of p-nitrophenyl-α-D-glucoside which it hydrolysed at 9% of the rate exhibited on p-nitrophenyl-α-L-arabinofuranoside. It degraded arabinan in an exo-manner, but exhibited no activity on carboxymethylcellulose, arabinogalactan, arabinoxylan, or oat spelt xylan. However, when it was incubated with the purified xylanase B, also obtained from C. acetobutylicum, it acted cooperatively to increase the rate of hydrolysis of oat spelt xylan. Arabinose was detected as one of the hydrolysis products.

Journal ArticleDOI
TL;DR: The amounts of lactic acid produced by the community increased as the environmental pH was lowered, and the levels of S. mutans, S. sanguis, and S. mitior populations began to increase and the S.Mitior population began to decline.
Abstract: Strains of Streptococcus mutans (biotype 1), Streptococcus sanguis, and Streptococcus mitior have been grown in mixed continuous culture in a semidefined medium under glucose limitation at a growth rate of D = 0.1 h−1. The effect of varying the environmental pH on the proportions of the different populations within the community has been determined. Initially the populations were allowed to reach steady state at pH 7.0 when S. sanguis was dominant with S. mutans and "S. mitior" maintaining similar populations. The medium pH was then lowered in steps of 0.5 pH units from pH 7.0 to 4.5, and the community was grown at each step for at least 15 generations. Viable counts of each species were made at 24-h intervals. The population ratios established at pH 7.0 remained relatively stable when the environmental pH was set at pH 6.5. However, after the medium pH was lowered to 6.0 (days 18–27), the population of S. mutans began to increase and the S. mitior population began to decline. A further change was seen at...

Journal ArticleDOI
TL;DR: Forty-two microorganisms were tested as biological control agents against Alternaria raphani and A. brassicicola for in vitro antagonistic ability, for ability to control the pathogens on naturally infected seeds germinated on moistened blotters, and in planting mix in growth chamber studies.
Abstract: Forty-two microorganisms were tested as biological control agents against Alternaria raphani and A. brassicicola. Tests were conducted for in vitro antagonistic ability, for ability to control the ...

Journal ArticleDOI
TL;DR: Industrial-scale winemaking confirmed the ability of two hybrid strains to produce similar amounts of glycerol to those observed in laboratory-scale fermentations and observed activities were lower in the products of the hybridization programme than in the original wine yeast strains.
Abstract: Wines that are lacking in body may be improved by the presence of greater amounts of glycerol. Wine yeast strains vary in their ability to produce glycerol. A programme of hybridizing yeast strains...

Journal ArticleDOI
TL;DR: The fungistatic compound viridin, produced by the fungus Gliocladium virens, was found to be irreversibly reduced to the phytotoxin viridiol in liquid culture.
Abstract: The fungistatic compound viridin, produced by the fungus Gliocladium virens, was found to be irreversibly reduced to the phytotoxin viridiol in liquid culture. Conversion occurred only in the prese...