摘要:

Spores ofBacillus popilliaewere isolated from a mixture of spores and vegetative cells by enzymatic digestion of the vegetative cells. Infectivity of the enzyme-treated spores was not affected and germination was enhanced. The enzyme complex, produced extracellularly by an aerobic sporeformer, also induced spheroplasts ofB.popilliae. Vegetative cells of bacteria in 13 of 23 genera were lysed by the enzyme but sporulating forms of all sporeformers tested were not. Thus, the enzyme can be used for the discriminate selection of sporangial stages of sporulation by the specific lysis of vegetative forms.

ISSN:0008-4166    

DOI:10.1139/m69-148

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

The effects of two nutritional elements (carbon and sulfur) and two environmental factors (pH and temperature) on growth and sclerotial production ofAspergillus nigerwere determined on a synthetic agar medium. The fungus grew and produced sclerotia under laboratory conditions on media containing wide ranges of carbon and sulfur sources. Of the 20 carbohydrates tested, only ribose, mannitol, and malonic, fumaric, and citric acids failed to induce production of sclerotia. A synergistic effect was observed on the formation of sclerotia when favorable and unfavorable carbon sources were supplied in different combinations. Of the 14 sulfur compounds tested, magnesium sulfate yielded the highest and sodium sulfite the lowest number of sclerotia. Raising the concentration of magnesium sulfate to 3 g/l increased the number of sclerotium initials and the number and dry weight of those which matured. In general, no correlation occurred between the number of sclerotia formed and their dry weights on different carbon or sulfur sources. Sclerotia were most numerous at pH 7.0 and 35 °C.

ISSN:0008-4166    

DOI:10.1139/m69-149

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Light and electron microscopic studies of human adenovirus types 2, 4, 6, and 18 infected HEp-2 cells revealed the induction of virus-associated, intranuclear paracrystalline formations. None of these crystalline structures were observed in abortively infected BHK-21 cells by these viruses. By histochemical techniques, the crystals only in Ad. 2 and Ad. 6 infected cells were visualized with the phase-contrast microscope and shown to be protein in nature but devoid of detectable amounts of nucleic acids. The crystals induced by Ad. 2 and Ad. 6 were frequently large, were polygonal in shape, appeared early after infection, and consisted of parallel tubules with a periodicity of 700 Å, whereas those induced by Ad. 4 and Ad. 18 were small, were irregular in shape, appeared later after infection, and consisted of parallel filaments with periodicities of 250 Å and 400 Å, respectively. Neither crystals nor virions were found in uninfected control cells. The relationship of the virus-associated crystals reported in the present study to those observed to date in other adenovirus–host systems was discussed.

ISSN:0008-4166    

DOI:10.1139/m69-150

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Multiplication of human adenovirus type 6 was demonstrated in established cultures of bovine cells. The virus replicated, producing characteristic cytopathic effects and undiminished infectivity, through six serial passages. By means of light and electron microscopy the appearance of viral inclusion bodies were comparable to those routinely observed in infected human cells. Intranuclear paracrystalline formations were also observed in the present virus–host system. The pathogenicity and host range of human adenovirus type 6 in relation to these properties of other adenoviruses were discussed.

ISSN:0008-4166    

DOI:10.1139/m69-151

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

From results of Adansonian, deoxyribonucleic acid base composition, and fine structure studies ofPseudomonas iodinum, it is suggested that this organism be removed from the genusPseudomonas. The cell wall structure ofP.iodinumwas found to be typical of the Gram-positive bacteria. Inclusion bodies were observed in cell sections and were found to be located at or near the septum and mesosomes of the cells.

ISSN:0008-4166    

DOI:10.1139/m69-152

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

The nine typing phages of the enteropathogenicE.coli0127:B8 have been studied by negative staining. They represent five morphological types. The phages 3, 7, and 9 possess tails with contractile sheath and belong to the group A of Bradley. Phages 2, 4, 5, and 6 have long tails without sheath (group B). Phages 1 and 8 show short tails of only 190 Å length (group C). Groups A and B include both phages with elongated heads (phages 3 and 5) and isometric heads. All isometric heads are octahedra. Phage 3 resembles T-even phages.

ISSN:0008-4166    

DOI:10.1139/m69-153

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

A homothallic isolate ofFusarium solaniproduced red perithecia when illuminated and grown on a simple basal medium containingL-tyrosine;L-phenylalanine; orD-glucose + NaNO3as a sole carbon and nitrogen source. Few or no perithecia formed in darkness on these media. Quantitative comparisons of perithecial formation in illuminated treatments indicated thatL-tyrosine was a significantly better sole source of carbon and nitrogen than eitherL-phenylalanine orD-glucose + NaNO3. There was no significant difference between the responses on media containingL-phenylalanine and D-glucose + NaNO3. If dark-grown treatments were subsequently illuminated, perithecia formed on media containingL-tyrosine andD-glucose + NaNO3but not onL-phenylalanine. The initial pH of the medium containingL-tyrosine did not seem to affect the fruiting response in illuminated cultures. A reduction in the amount ofL-tyrosine in the basal medium resulted in a corresponding decrease in perithecial formation.The results are discussed in connection with a possible relationship of sexual reproduction, the light requirement, and tyrosine metabolism.

ISSN:0008-4166    

DOI:10.1139/m69-154

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Polyporus versicolordegrades rutin by a route differing from that established inAspergillus flavus. Carbon monoxide is not a product of the reaction and hydrolysis of the glycosidic bond is not a prerequisite for oxidative attack of the flavonol nucleus.Culture filtrates ofPolyporus versicolorreadily degrade rutin, producing a dark brown pigment. This degradation of rutin appears to be mediated by a polyphenol oxidase type of enzyme as all attempts to separate flavonol oxidation from pigment production were unsuccessful. The results indicated that both activities were associated with a single protein. Other enzymes involved in rutin breakdown by theAspergillussystem (i.e. the hydrolases: glycosidase and the depside esterase) were not present in rutin-grown filtrates ofPolyporus versicolor.

ISSN:0008-4166    

DOI:10.1139/m69-155

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Working with dwarf bean plants, the authors studied changes in the lengths of fungal mycelium in rhizosphere and non-rhizosphere soil at different stages of plant growth, using the soil-agar film technique. In general it appears that the stimulation of microbial growth in the rhizosphere was slight in the early stages of plant growth; the length of mycelium in rhizosphere soil increased with increase in vegetative growth of the plants, and decreased markedly at senescence of the plants.Respirometric studies on rhizosphere and non-rhizosphere soil samples indicated greater activity in rhizosphere soil. The degree of stimulation of activity in rhizosphere soil varied according to the stage of plant growth, with maximum activity corresponding to the stage of maximum vegetative growth of the plants.

ISSN:0008-4166    

DOI:10.1139/m69-156

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Coagulase-negative pathogenic staphylococci were studied physiologically and serologically to determine their relationship toStaphylococcus aureus. When 46 characters were studied and tallied, the 21 coagulase-negative pathogenic strains made up a heterogeneous intermediate group sharing not all the characters ofS.aureusbut appreciably more thanS.epidermidis. Some characters among the coagulase-negative pathogens indicating a relationship toS.aureuswere serotyping, lysostaphin sensitivity, growth rates, and endogenous respiration. Seventy-one percent of the coagulase-negative pathogenic strains were resistant to penicillin; of these, 80% were multiple antibiotic resistant.From these results it would appear that the genusStaphylococcuscannot be divided satisfactorily into demarcated species but that strains within this genus form a continuous spectrum between the two presently recognizable extremes with new subtypes evolving as characters are lost. If a species must be designated under the existing system of classification, a strain producing coagulase can be calledS.aureus. However, coagulase-negative pathogenic strains cannot be classified with accuracy asS.epidermidison the basis of the absence of this single character, coagulase.

ISSN:0008-4166    

DOI:10.1139/m69-157

出版商:NRC Research Press    

年代:1969

数据来源: NRC