摘要:

The introduction of growing microplasmodia into a balanced salt solution induces the formation of hard-walled units (spherules) within 24 h to 36 h. The respiration rate was followed throughout differentiation and was found to decrease from a starting value of 62 μl O2/mg protein per hour to 17.5 μl O2/mg protein per hour after 40 h in the salt solution. The use of exogenous glucose and protein catabolism was also studied, and the results indicate that proteins are a major energy source during spherulation. On the basis of the data from this study and the results of other investigators, the process of spherulation has been divided into three developmental periods.

ISSN:0008-4166    

DOI:10.1139/m74-017

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Direct extraction of nucleic acid from mycelium ofPenicillium stoloniferumyielded five viral double-stranded ribonucleic acid (dsRNA) components, transfer RNA (tRNA), and a deoxyribonuclease-sensitive fraction of deoxyribonucleic acid. Analysis of fungal cells from a submerged fermentation demonstrated detectable viral dsRNA and both types of virus-like particles (VLP) at 36 h with an increase in viral RNA synthesis for both VLP parallel to fungal growth up to 72 h followed by mycelial autolysis and loss of viral RNA. Replication of nucleic acid from VLP was measured by (i) incorporation of14C-2-uracil into viral dsRNA, (ii) purification of viral dsRNA by cellulose column chromatography and subsequent ultraviolet absorption determination, and (iii) analysis of nucleic acid species by poly-acrylamide gel electrophoresis.

ISSN:0008-4166    

DOI:10.1139/m74-018

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The relationship between inoculum density and the number of colonies ofVerticillium dahliaeKleb./unit length of root from plants growing in naturally infested soils is shown to be linear. The evidence supports the contention that the propagules giving rise to these colonies are microsclerotia or small groups of microsclerotia embedded in fragments of plant tissue. Thus the colonies growing on plant roots are a quantitative measure of the number of these propagules in soil. The data show that plant roots are an extremely sensitive trap and can be used to measure low numbers of microsclerotia.

ISSN:0008-4166    

DOI:10.1139/m74-019

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Cultures ofParamecium caudatumincubated with 7 × 10−7 M 2-naphthylamine were rapidly killed when exposed to light of 366 nm. Cultures not exposed to the amine were unaffected by the light; cultures kept in the dark were unaffected by the amine.Escherichia coliK-12 populations were markedly reduced after irradiation of suspensions in water containing 3 × 10−4 M 2-naphthylamine with light simulating natural sunlight in intensity and wavelength distribution. Suspensions ofE.coliin deionized water were unaffected by the light andE.colisuspended in solutions of the amine but kept in the dark were also unaffected. Since 2-naphthylamine is a known water pollutant these results may be of ecological importance.

ISSN:0008-4166    

DOI:10.1139/m74-020

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

An extremely stable, particulate, bacteriocin, namely xanthacin, has been found inMyxococcus xanthusf b after mitomycin C induction. Xanthacin is resistant to trypsin, protease type VI, RNase, DNase, sodium dodecyl sulfate (SDS), acetone, ether, ultraviolet irradiation, and autoclaving. A high-titer preparation was obtained after partial purification by pervaporative concentration, differential centrifugation, molecular sieve chromatography, and density gradient centrifugation. Electron microscopy of platinum-shadowed and uranyl acetate stained preparations revealed the presence of circular bodies of varied size which resembled membrane fragments.

ISSN:0008-4166    

DOI:10.1139/m74-021

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The fluorescent antibody technique was found to be highly promising as a new approach to the study of mycorrhizae. Fluorescent antibodies prepared against two mycorrhizal fungi,Thelephora terrestrisandPisolithus tinctorius, were effective and specific as microscopic stains for those fungi and their corresponding mycorrhizae.Thelephora terrestrisantibody gave zero, andP.tinctoriusantibody gave five cross-reactions of moderate intensity, in tests with 31 diverse nonmycorrhizal fungi.Armillaria melleareacted nonspeciflcally with several fluorescent antibodies.

ISSN:0008-4166    

DOI:10.1139/m74-022

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Thiobacillus ferrooxidans, grown on either ferrous sulfate, lead sulfide concentrate, or chalcopyrite concentrate demonstrated oxygen uptake and CO2fixation in the presence of ferrous sulfate, chalcopyrite ore, pyrite ore, and red antimony trisulfide. Lead suifide-grown cells could oxidize lead sulfide ore and galena, using the energy obtained for CO2fixation. All three cell types could oxidize nickel sulfide, but could not fix CO2in the presence of this substrate. The solubilization of metals from the substrates and the crystallographic changes in the insoluble residues are reported.

ISSN:0008-4166    

DOI:10.1139/m74-023

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

There was no significant difference in serological titers when different groups of guinea pigs (Hartley strain) infected with varying doses of mycelial phase ofHistoplasma duboisii(one, two, seven, and no injections) were superinfected withListeria monocytogenes6 months later. The immunological response of infected animals which received two biweekly intraperitoneal injections ofHistoplasma duboisiiand were superinfected after 40 days with homologous and heterologous organisms was used for comparison. In general, animals receiving a single injection ofHistoplasma duboisiihad no complement-fixing antibodies against this antigen; however, positive skin and precipitin reactions did occur. Animals receiving several injections ofHistoplasma duboisiihad a higher complement-fixation titer (1:16 to 1:256) than those with two injections (1:8 to 1:32). After superinfection withListeria monocytogenes, animals which received seven injections ofHistoplasma duboisiishowed a slight reduction in the number of rosette-forming cells againstListeria monocytogenesantigens when compared with the controls.

ISSN:0008-4166    

DOI:10.1139/m74-024

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

A strain ofMyxococcus xanthus, referred to asM.xanthusTA, has been isolated which produces an antibiotic capable of inhibiting growth of certain Gram-positive and Gram-negative bacteria. Antibiotic production was significantly inhibited when the concentration of protein hydrolysate in the production medium exceeded 1%. The antibiotic was purified over 1000 times to apparent homogeneity by silicic acid chromatography and by a variety of preparative alumina thin-layer chromatographic procedures. The purified antibiotic was partially characterized by its chromatographic behavior in six solvent systems, stability to acid, alkali and heat, infrared, ultraviolet, and mass spectra. The antibiotic has a λmaxof 242 nm in methanol.

ISSN:0008-4166    

DOI:10.1139/m74-025

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The morphology of resting mycelium in isolates ofVerticillium albo-atrumvaried according to cultural conditions; on natural media hyphae were modified to form unbranched, swollen, pigmented, resting mycelium whereas on artificial media the hyphae became highly segmented, torulose, and intertwined to form mycelial knots. In one isolate, aerial hyphae sometimes developed external bands, or 'blisters,' of electron-dense material deposited in discrete regions along the length of the hyphae. The function of these modified aerial hyphae is probably different from that of resting mycelium and might represent an early stage in the formation of some hitherto undescribed structure.

ISSN:0008-4166    

DOI:10.1139/m74-026

出版商:NRC Research Press    

年代:1974

数据来源: NRC