ISSN:0008-4166    

DOI:10.1139/m80-128

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Germination of isolated spores ofSchizosaccharomyces pombe, measured by loss of refractility and of resistance to ethanol, was induced in a simple solution of glucose. The subsequent outgrowth steps (swelling and germ-tube formation), however, did not occur in the glucose solution. Normal outgrowth required almost all nutrients essential to vegetative growth. Germination was also induced by sucrose and mannose but only weakly by fructose. Glucose-germinated spores normally outgrew in the fructose-containing nutrient medium. Generation of CO2from exogenous fructose by ungerminated spores was only 10% of that from exogenous glucose. These facts suggested that ungerminated spores were defective in the ability to utilize fructose and that germinated spores acquired this ability.

ISSN:0008-4166    

DOI:10.1139/m80-129

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

The genusHalomonas(type speciesH.elongata) is a new bacterial genus composed of salt tolerant bacteria. The growth characteristics and morphology of the type strain of this bacterial group were studied using both complex and defined media. The salt tolerance of the bacterium decreased significantly on defined medium, suggesting that the type of growth medium used has a great effect on bacterial salt tolerance. Experiments on the effect of temperature on salt tolerance indicate that a temperature of 30 °C permits the greatest salt tolerance. In all of these experiments 0.375 and 1.37 MNaCl yielded the most rapid growth rates while 1.37 and 2.5 MNaCl permitted the greatest temperature tolerance. TheHalomonasstrain was found to have an absolute requirement for the Na+cation. While NaNO3and NaBr would substitute for NaCl in the growth medium, when LiCl, NH4Cl, MgCl2∙6H2O, or KCl was substituted for NaCl, the medium would not support growth. The bacterium consistently retained its rod shape regardless of the NaCl concentration in both complex and defined media. The data indicate that even though this bacterium has been in culture for over 5 years it is still well adapted to life in its natural environmen

ISSN:0008-4166    

DOI:10.1139/m80-130

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

The use and performance of an improved diagnostic and selective medium, PEMBA (polymyxin pyruvate egg yolk mannitol bromothymol blue agar), for the detection ofBacillus cereusin foods is described. The distinct colonial appearance ofB.cereuson PEMBA permitted the recognition of both strains: those that do precipitate egg yolk and those that do not react with egg yolk. A staining procedure, used to demonstrate microscopically both the presence of lipid globules in vegetative cells and spore morphology of isolates, proved a rapid and reliable confirmatory test which gave complete agreement with a battery of biochemical tests used for this purpose. The quantitative recovery ofB.cereuson PEMBA from 143 food samples was not significantly different from counts on KG (Kim and Goepfert), MYP (mannitol egg yolk phenol red), and McClung's media, and the selectivity of PEMBA was generally superior.

ISSN:0008-4166    

DOI:10.1139/m80-131

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Acetivibrio cellulolyticus, an isolate from an established sewage sludge culture, degraded cellulose powder, Avicel cellulose, and cellobiose. The organism showed maximum cellulose degradation in a medium containing 10 g/L of cellulose and it could also degrade cellulose in media containing up to 75 g/L of cellulose. During the exponential growth phase, large quantities of cellulolytic enzymes were found extracellularly whereas cellobiase activity was cell associated. The crude culture supernate contained endo- and exo-glucanase activities with a pH optimum at 5.0 and a temperature optimum at 50 °C. Maximum cellulase activities were detected in 2- to 3-day-old cultures grown on 1 g/L of cellulose. Cellulose concentration above 10 g/L caused the adsorption of these enzymes to the substrate and consequently lowered their detection in the supernate. The activities at 50 °C for endoglucanase, exoglucanase, and filter paper degrading ability, expressed as micrograms of glucose equivalents released per minute per milligram of protein culture supernate, were 510, 135, and 40 respectively.

ISSN:0008-4166    

DOI:10.1139/m80-132

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

The metabolites produced whenMonocillium nordinii(Bourchier) W. Gams, a destructive mycoparasite of pine stem rusts, is grown in liquid culture have been separated and identified. The metabolites include the known compound monorden (1) and five new substances, monocillin I (2), monocillin II (4), monocillin III (3), monocillin IV (5), and monocillin V (6). Structural assignments and chemical correlations of the five new compounds are reported and the absolute configuration of monorden is assigned. The antifungal spectra of the three major metabolites are reported. Monorden and monocillin I show pronounced activity against a wide variety of fungi, includingCeratocystis ulmi, the cause of Dutch elm disease. Extraction of the mycelium yielded averufin (13), along with a pigment C18H12O6, as yet unidentified.

ISSN:0008-4166    

DOI:10.1139/m80-133

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Cell extracts of hyphae ofFusarium oxysporumf. sp.lycopersicirapidly transferred the methyl group ofS-[methyl-3H]adenosyl-L-methionine (Ado-Met) to endogenous phosphatidylethanolamine (PE). About 80% of the radioactivity incorporated into the phospholipid fraction was found in phosphatidylcholine (PC) while the rest of the radioactivity was present in the intermediates monomethylphosphatidylethanolamine (MePE) and dimethylphosphatidylethanolamine (DiMePE). The phospholipid methylating system had a pH optimum of 8.5, aKmof 30 μm for Ado-Met, and aVmaxof 10 nmol/h per milligram protein. The specific activity of the methylating system was highest in early log phase and lowest in the late log phase of growth.The activity of the cell-free methylating system was reduced by incubation at temperatures above 25 °C, and at 37 °C about 50% of the initial methylating activity remained after incubation for 15 min. In contrast, the activity of thein vivomethylation system almost doubled when the incubation temperature was raised from 25 to 37 °C.

ISSN:0008-4166    

DOI:10.1139/m80-134

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Ten of the 14 strains ofBacillus cereusstudied were isolated from pasteurized soil samples by a new selective technique which consists of the use of anaerobic enrichment cultures in peptone medium containing 0.5% KNO3. The 19 strains ofB.megateriumuse the following 21 sources of carbon and energy:D-glucose,D-galactose,D-fructose,D-mannose,D-glucosamine,D-gluconate,D-ribose, sucrose, cellobiose, maltose, raffinose,D-mannitol, glycerol, glycerate, pyruvate, fumarate,trans-aconitate,DL-aspartate, asparagine,L-glutamate, andL-glutamine. The 14 strains ofB.cereususe the following 11 compounds:D-glucose,D-fructose,D-mannose,D-glucosamine,D-ribose, maltose, trehalose, glycerol, acetate, pyruvate, andL-glutamine. The eight strains ofB.cereusvar.mycoidesuse the following nine compounds:D-glucose, salicin,D-ribose, cellobiose, maltose, trehalose, glycerol, acetate, and pyruvate. Numerical taxonomy based on 151 characters shows that the 41 strains form two distinct groups. Group A includes the 19 strains ofB.magateriurn; group B includes the 14 strains ofB.cereusand the 8 strains ofB.cereusvar.mycoides. The guanine + cytosine content of the DNA of each strain was determined. The following mean values were obtained:B.megaterium, 40.6% ± 0.8;B.cereus, 38% ± 0.9;B.cereusvar.mycoides, 38.4% ± 1.1.

ISSN:0008-4166    

DOI:10.1139/m80-135

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Thirty-one denitrifying strains ofBacilluswere isolated from soils of diverse origin by anaerobic enrichment culture at 32 °C in peptone medium containing nitrite. One strain was isolated when nitric oxide was provided as the sole terminal acceptor of electrons. All 32 belong to the second morphological group of the genusBacillus. They denitrify NO3−and NO2−, are mesophilic, auxotrophic, and oxidase-positive. The numerical taxonomy of these 32 strains plus that of 15 strains isolated previously under the same conditions from tropical soils was done on the basis of 108 morphological, physiological, and biochemical characters. It reveals great heterogeneity. The DNA base composition, on the other hand, varies little from one strain to the other: the mean percentage of guanine + cytosineis40.5 ± 1.1. Two strains are related toBacillus azotoformans. The other strains are clearly distinct from that species as well as fromB.brevis. These results do not allow us to draw any final taxonomic conclusion. They are of some ecological interest because such bacteria seem to be ubiquitous in both temperate and tropical soils.

ISSN:0008-4166    

DOI:10.1139/m80-136

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

The growth temperature of the axenic strain ofDictyostelium discoideum, Ax-2, influences its subsequent rate of development. Despite the fact that many other microorganisms exhibit homeoviscous adaptation in response to temperature, the altered rates ofD.discoideumdevelopment are not due to a response to modified membrane fluidity. Growth temperature does not affect the fluidity of the cell membranes as determined by electron paramagnetic resonance and there are no systematic temperature dependent variations in fatty acid composition or sterol:phospholipid ratio.

ISSN:0008-4166    

DOI:10.1139/m80-137

出版商:NRC Research Press    

年代:1980

数据来源: NRC