摘要:

A random selection procedure was used to isolate a temperature-sensitive (ts) mutant of human adenovirus type 4 (Mastadenovirus h 4 tsl) from nitrous acid mutagenized virus stock. The mutant displayed restricted growth at the nonpermissive temperature of 39 °C. Analysis of the mutant grown at 39 °C, by two-dimensional immunoelectrophoretic analysis, showed the mutant to be defective in the expression of the penton base and fibre structural components. The mutant was, however, capable of synthesizing immunologically reactive hexon components. Temperature-shift experiments revealed detectable fibre and penton to be present following shift-down from 39 to 32 °C. Time-sequence analysis of shift-down experiments suggested a possible defect in processing of the components, as indicated by an increase of immunologically detectable penton base. The ability of the mutant to assemble viruslike particles at 39 °C was confirmed by electron microscopy. Though the particles assembled appeared as mature virions, crystalline arrays of packed particles were less in number and somewhat smaller in size than those observed at 32 °C.

ISSN:0008-4166    

DOI:10.1139/m84-022

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

Fusariumwas recovered from only 1 of 14 Pacific Northwest coniferous forest soils but from all 7 nursery soils tested. Assays using high concentrations ofFusarium oxysporummacroconidia added to soil determined that forest soils stimulate macroconidial germinationoften followed by germ-tube lysis or the formation of stunted chlamydospores, while nursery soils support little macroconidial germination. Treatment of forest soils with aerated steam (minimum of 45 °C for 30 min), radiation, or propylene oxide reduced the amount of germination in forest soils, suggesting that the forest soil microbiota is involved in the stimulation of macroconidial germination. Bacteria isolated fromF.oxysporumhyphae placed in forest, field, or nursery soils on nylon screens did not significantly influence germ-tube lysis when combined with macroconidia in a nutrient broth. Chemical, physical, and nutritional properties of forest soils likely affect the capacity of the forest soil microbiota to influenceFusariummacroconidial germination and germ-tube lysis.

ISSN:0008-4166    

DOI:10.1139/m84-023

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

A closed test tube assay was developed for measuring the root colonization capacity of bacteria in raw soil–sand. Bacteria were coated onto seeds at inoculum levels of 103– 109colony-forming units (cfu) per seed, and root-colonizing bacterial strains successfully grew along the emerging radicle. Quantification of specific bacterial populations on roots was highly reproducible between experiments with the assay. Of 54 strains tested, 24 colonized roots at populations of 104to 106 cfu/g root. All root-colonizing strains were Gram negative. Two fluorescent pseudomonad strains that failed to colonize maize roots in raw soil did colonize in autoclaved soil. Captan seed treatment and temperature of incubation (14 and 24 °C) had no substantial effect on subsequent root colonization. Root population densities determined in the sand–soil assay were comparable with those determined with plants grown in soils under greenhouse conditions.

ISSN:0008-4166    

DOI:10.1139/m84-024

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

Conidia of the entomogenous fungusErynia variabilisgerminate vegetatively on the cuticular surface of adults of the lesser housefly,Fannia canicularis, and on a basal agar growth medium in which cuticular lipid extracts of adult flies have been incorporated. Formation and discharge of secondary spores occur on puparial cuticles and on media in which puparial cuticle lipid extracts have been included. Relative free fatty acid compositions of puparial and adult cuticle lipid extracts are nearly identical, but adults average ca. five times the concentration of free fatty acids on their cuticle surface as that found on puparia. A regulatory role for esterified fatty acids in conidial germination is suggested. Limitation ofE.variabilisto adult dipteran hosts is postulated to be due in part to characteristics of the fatty acids of this order of insects: the presence of sufficient oleic acid to induce germination; high levels of palmitoleic acid to enhance mycelial growth; and low levels of linoleic and linolenic acids, which have deleterious effects on spore germination and mycelial proliferation.

ISSN:0008-4166    

DOI:10.1139/m84-025

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

Chemical analyses of the microcyst cell wall ofDidymium iridiswere done to compare it with other well-studied organisms,Physarum polycephalumandPhysarum flavicomum. Large wall fragments were obtained by breakage in a Braun homogenizer. Chemical analyses of purified walls identified neutral sugars, protein, and hexosamine as the major components. Wall polysaccharides were mostly composed of galactosamine with smaller amounts of glucose and galactose. The protein component consisted of large quantities of threonine and aspartate–asparagine with trace amounts of the sulfur-containing amino acids. Most of the wall protein was soluble in alkaline urea. Sodium dodecyl sulfate – polyacrylamide gel electrophoresis was used to identify seven major bands, at least four of which are acidic glycoproteins. Most of the galactosamine was associated with the urea – hot alkali insoluble fraction comprised mostly of glucose. This galactosaminoglucan was partially sulfated and acetylated and arranged as microfibrils that maintain cell shape.

ISSN:0008-4166    

DOI:10.1139/m84-026

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

Histochemical techniques were used to determine the nature and distribution of nutrient reserves and other materials in sclerotia of two isolates ofBotrytis cinereaand one isolate ofB.fabae. All isolates showed similar staining reactions. Hyphal walls contained chitin and β-glucans, including β-1,3-glucans, while rind cell walls also contained a melanic pigment. Medullary hyphae were surrounded by a continuous matrix of β-glucans. The intracellular nutrient reserves found were protein, glycogen, polyphosphate, and lipid.

ISSN:0008-4166    

DOI:10.1139/m84-027

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

Investigations were conducted to compare the forest soil microflora of three "ecologically analagous" sites, 1, 2, and 3, situated 2.8, 6.0, and 9.6 km, respectively, downwind of a sour gas plant emitting SO2. Bacteria and fungal propagules were isolated by dilution plating, and relative tolerance to the dissociation products of SO2was tested by plating onto media also amended with Na2SO3or NaHSO3. There were significant reductions both in total numbers of bacteria and starch-utilizing bacteria from the organic soil (F/H horizon) of site 1. A greater proportion of the bacteria from site 1 were spore formers compared with sites 2 and 3. There was no significant difference between sites in the number of fungal propagules isolated from the organic soil, but a smaller proportion of fungi recovered from site 3 were tolerant to sulphite or bisulphite compared with sites 1 and 2. No differences between sites were detected in terms of bacterial tolerance to the dissociation products of SO2. There were no major differences in the numbers of microorganisms isolated from the mineral soil or in their tolerance to bisulphite or sulphite, although in September, fewer bacteria were isolated from site 1, and a greater proportion of these were spore formers.

ISSN:0008-4166    

DOI:10.1139/m84-028

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

Persistent diabetes was induced in male Slc: ddY mice by a single intraperitoneal injection of 200 mg/kg streptozotocin (STZ). In these mice, the numbers of aerobic gram-negative bacilli, staphylococci (including micrococci), and streptococci increased, while those of other bacteria were almost unchanged in both oral and caecal floras. The mice were vulnerable to oral infection ofSalmonella enteritidis, intranasal infection ofKlebsiella pneumoniaeandSerratia marcescens, and contact infection with mice infected withS.enteritidisandK.pneumoniae. These findings suggest that STZ-treated mice might be a useful model for investigating opportunistic infection.

ISSN:0008-4166    

DOI:10.1139/m84-029

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

The mean size and percentage of budded and unbudded cells ofCandida albicansgrown in batch culture over a wide range of doubling times have been measured. Cell volume decreased with increased doubling time and a nonlinear approach to an asymptotic minimum was observed. When cells were separated by age according to bud scars, each age showed a similar decrease. During each cell division cycle, size increased slowly during both budded and unbudded periods so that each generation was significantly larger than the preceeding. There was no difference in size between the parent portion of budded cells and unbudded cells of the same age. Time-lapse photomicroscopy of cells growing on solid medium showed that cells divide asymmetrically with larger parents having a shorter subsequent cycle time than the smaller daughter, although the time utilized for bud formation was similar. When cells were shifted from a medium supporting a low growth rate and small size to a medium supporting a faster growth rate and larger size, both budded and unbudded cells increased significantly in size. As the doubling time increased, both the budded and unbudded portions of parental and daughter cycles increased.

ISSN:0008-4166    

DOI:10.1139/m84-030

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

The peptidoglycan ofEscherichia coliK-12 strain AB264 was isolated by treating whole cells with sodium dodecyl sulfate and was purified by deoxyribonuclease, ribonuclease, and trypsin treatment. Like the peptidoglycan ofBacillus subtilis, this peptidoglycan proved able to bind substantial amounts of metallic ions from aqueous solution. In particular, most metals of the transition I series were bound from solution in amounts ≥ 1 μmol/mg dry weight peptidoglycan.

ISSN:0008-4166    

DOI:10.1139/m84-031

出版商:NRC Research Press    

年代:1984

数据来源: NRC