摘要:

Data are given on two aspects of the study of fungi in glass microbead systems. Using two fungi (Penicillium decumbensandCylindrocarpon destructans) the effect of shaking on microbead–water–spore suspensions was studied and it was shown that such shaking causes extensive killing of fungal spores (this effect being much greater for spores ofP.decumbensthan for spores ofC.destructans). Using the same fungi, the effect of moisture tension on movement of spores was studied and data are given showing that the spores may move considerable distances during changes in water tension, this movement being limited by spore and pore size.

ISSN:0008-4166    

DOI:10.1139/m70-092

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

A study was made of the open windrow method of municipal solid waste composting as related to those factors that might influence cellulose decomposition. Composting temperatures reached a maximum (55–65 °C) at 3 weeks and then gradually decreased during the rest of the 49-day process. The pH values of compost samples homogenized in distilled water decreased slightly during the initial stages of the process and then increased gradually to final values of 7.0–8.5. Clarified compost extracts were assayed for cellulase activity by measuring the hydrolysis rate of carboxymethylcellulose (CMC). Maximal cellulase activity occurred at 65 °C, pH 6.0, with a CMC concentration of 2.5%. The cellulase activity of compost increased 10-fold at a logarithmic rate while the cellulose content decreased 50%. In a preliminary search for microorganisms active in cellulose degradation during the composting process, three cellulolytic species were isolated; these were identified asAspergillus fumigatus, aBacillusspecies, and aThermoactinomycesspecies of theActinobifidagroup.

ISSN:0008-4166    

DOI:10.1139/m70-093

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The animal-maintained "phase I" (Ph I) and the egg-grown "phase II" (Ph II) strain ofCoxiella burnetii(Cb) were each made up of a natural mixture of particles with different densities (23). When examined by immunofluorescence (IF), their populations behaved as if they were monophasic, both before and after separation by cesium chloride. The Ph I strain, made up of particles of both densities, showed Ph I reactivity and particles of the Ph II strain showed Ph II reactivity. When L-cells (which represent a restrictive host-system for Ph I Cb) were inoculated with large doses of either the Ph I strain of Cb or with particles of a relative density of 1.32 (Ph I), only a few L-cells contained Cb which stained with biphasic serum. The Ph II strain of Cb and particles with a density of 1.27 (Ph II) multiplied well in L-cells and stained readily with Ph II antiserum. Particles which stained with biphasic serum, however, were seen in a few L-cells which had a multiple infection with Ph II Cb. A large inoculum of artificial mixtures of Ph I and Ph II strains of Cb produced many particles in L-cells which stained predominantly with biphasic serum. Interference of growth of Cb occurred using a small inoculum of the mixtures of Ph I and Ph II.Mixtures of active particles of Ph I Cb (host-dependent) and of heat-inactivated Ph II Cb, produced enhancement of growth of Cb. The reactivated Cb were stained predominantly with Ph II antiserum. The possibility that phenotypic mixing of Cb is related to its mode of replication is discussed.

ISSN:0008-4166    

DOI:10.1139/m70-094

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The effects on nitrification as studied by soil perfusion techniques of the herbicides 3′, 4′-dichloro-propionanilide (propanil), 3-(3, 4-dichlorophenyl)-1, 1-dimethylurea (diuron), 3-(3, 4-dichlorophenyl)-1-methoxy-1-methylurea (linuron), and the compounds 3-(3, 4-dichlorophenyl)-1-methylurea (DMU), 3, 4-dichlorophenylurea (DU), 3, 4-dichloroaniline (3, 4-DCA), and 3, 3′,4, 4′-tetrachloroazobenzene (TCAB) are reported. Propanil at a concentration of 100 μg/g of soil resulted in marked retardation of the nitrification process for about 2 months. High application rates of linuron, diuron, DU, and TCAB were required to inhibit nitrification. Among the degradation products, 3, 4-DCA inhibited the oxidation of NH4-N to NO2-N, but was inactive against the organisms oxidizing NO2-N to NO3-N. DMU inhibited the oxidation of NO2-N to NO3-N byNitrobacterspp., resulting in accumulations of NO2-N in soil from NH4-N. Moreover, the presence of DMU could be detected within 1 month after application of either linuron or diuron to soil by the changes in normal nitrification patterns. The significance of antimicrobial activity of the herbicides and degradation products is discussed.

ISSN:0008-4166    

DOI:10.1139/m70-095

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Several hypotheses explain the heat resistance of bacterial spores in terms of a hydrophobic nature of the spore surface and possibly also the spore interior. The water-sorption properties of naturally hydrated spores which had never been dehydrated before the experiment were studied. The rate of loss of water over P2O5at 50 °C was measured in a closed chamber by remote weighing with a Cahn electrobalance. The hygroscopicity expressed as percentage of water bound by the sample ataw = 1, 25 °C was as follows.(I) Chemicals:albumin, 70.5; starch, 42.9.(II)Clostridium botulinum33A, a heat-resistant strain: spores, 47.0; residue (spores heat killed at 121 °C for 30 min), 50.4; exudate (material released from heat-killed spores) 63.1; vegetative cells, 70.3.(III)C.botulinum, type E, strain Beluga, a heat-sensitive strain: spores 62.5; residue, 61.3; exudate, 77.3.It is postulated that molecular masking in the spore is responsible for low binding of water, electrical and chemical inertness, biological dormancy, and high heat resistance of bacterial spores.

ISSN:0008-4166    

DOI:10.1139/m70-096

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Aedes aegyptiwere infected with chikungunya virus by being fed on a blood–virus suspension poured over a sugar cube. The virus infection in the salivary glands was then studied with the electron microscope. In the proximal portion of the lateral lobes, 250–310 Å virus precursor particles were seen in the nucleus, in the cytoplasm, and on the membranes of cytoplasmic vesicles. Enveloped 500–580 Å virus particles with a 250–310 Å core were seen within the vesicles, in intercellular spaces, and in large numbers in the apical cavity and periductal space. In the distal portions of the lateral and median lobes precursor particles were present in the nucleus and cytoplasm, but no cytoplasmic vesicles were seen. Numerous enveloped virus particles were seen in the apical cavity and periductal space, and in the median lobe within the duct lumen as well. No evidence of virus replication was seen in the intermediate portion of the median lobe.In the distal portions, virus particles were frequently associated with a concentration of the secretory material. No other microscopically visible pathological changes were seen in the infected salivary glands.

ISSN:0008-4166    

DOI:10.1139/m70-097

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

A chemically defined medium for the cultivation ofValsa friesiiDuby (Fuckel) PRL 1736 has been developed and conditions established for accumulation of high yields ofm-cresol in the culture filtrate. Yields of 1 g per liter as determined by colorimetric assay using 4-aminoantipyrine are obtained after 10 days' incubation in shake culture at 28 °C in the absence of light on a medium containing glucose, 15 g; alanine, 2 g; K2HPO4, 0.3 g; KH2PO4, 0.2 g; salts (0.2 g MgSO4∙7H2O, 0.1 g NaCl, 0.1 g CaCl2, 0.015 g FeSO4, and 0.25 mg ZnCl2); and vitamins (4 mg each of thiamine HCl, pyridoxin HCl, 10 mg inositol, and 10 μg biotin) per liter of distilled water. The organism is shown to tolerate higher concentrations ofm-cresol than do eight other fungi teste

ISSN:0008-4166    

DOI:10.1139/m70-098

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

A total of 59 asporogenous mutants ofBacillus licheniformiswere isolated after treatment with nitrosoguanidine or ethyl methanesulfonate. Forty-one of the 59 asporogenous sites were mapped by SP-15 mediated transduction on an abbreviated genetic map ofB.licheniformiswhich contained 12 reference markers. Linkage data revealed that genes for sporulation occupied at least five separate and distinct areas of the chromosome.B.licheniformiswas noted to resembleB.subtilisin that most of the spore genes in both species mapped in a cluster to the left of an identical sequence of terminal auxotrophic markers. The terminal spore cluster inB.licheniformis, as inB.subtilis, contained a locus which when defective, blocked the synthesis of a protease believed to regulate an early function of spore formation.

ISSN:0008-4166    

DOI:10.1139/m70-099

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

A rapid and sensitive method has been developed to determine the degree of cross-reactions within the picornavirus group by the indirect method of fluorescent antibody staining in green monkey kidney cells. The viruses included in the study were poliovirus type 1, 2, and 3; echovirus type 3, 9, and 11; and coxsackievirus type A9 and B5. It has been found that the cross-reactions are in fact extensive amongst the viruses tested. The heterologous reactions were almost as strong as homologous reactions. The degree of group reactivity was unexpected and its implication and advantages are discussed.

ISSN:0008-4166    

DOI:10.1139/m70-100

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The activity of the enzyme, isocitrate lyase, was repressed in glucose cultures ofSchizophyllum communeand derepressed in acetate-grown mycelium of this basidiomycetous fungus. The maximum acetate-derepressed level of this soluble enzyme was comparable in individual homokaryotic mycelium or in the dikaryon. Addition of CO2, NaHCO3, or CaCO3did not significantly derepress isocitrate lyase activity in glucose-cultures. Neither normal dikaryotic fruiting nor its inhibition by carbon dioxide resulted in marked and sustained changes in isocitrate lyase. Thus, a fluctuation in isocitrate lyase activity does not appear to be the salient response ofS.communeto increased CO2tension.

ISSN:0008-4166    

DOI:10.1139/m70-101

出版商:NRC Research Press    

年代:1970

数据来源: NRC