摘要:

Some observations have been made on the infectious agent, the histopathology, and the incubation period of a polyhedrosis in western hemlock looper larvae. External and internal symptoms are generally similar to nuclear polyhedrosis in other Lepidoptera. Infection is first detectable in fat body nuclei, other susceptible tissues being blood, hypodermis, and tracheal matrix. Larvae subjected to a short period of starvation just prior to oral infection show a shorter incubation period than non-starved larvae. The polyhedral inclusion bodies range from 0.5 μ to 5.0 μ in diameter. Electron micrographs of dissolved polyhedra show their contents to be largely rod-shaped viruses measuring approximately 40 mμ × 290 mμ.

ISSN:0008-4166    

DOI:10.1139/m57-089

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

This study was designed to determine whether the method of preparing an inoculum could influence the results obtained from comparative nutritional experiments.The quantity of inoculum used to start cultures ofClaviceps purpureaclearly affected the rate of growth, and to a lesser extent total growth on mannitol, and growth rate varied directly with increasing inoculum size.The quantity of inoculum used to start cultures also affected the uniformity of growth among replicas. As the amount of inoculum decreased, the variation among replicas increased and this affected the power of the experiment to distinguish between similar mean growth responses. These observations suggested that standardization of the quantity of inoculum might be profitable. It is proposed that the smallest amount of inoculum represented by a coefficient of variation of about 10% be considered an acceptable inoculum. Such an inoculum is large enough that growth among replicas is not too irregular and small enough that nutrients are not unnecessarily added to the experimental medium through the inoculum.The effect of heterokaryosis on uniformity of growth is demonstrated withIsaria cretaceavan Beyma.

ISSN:0008-4166    

DOI:10.1139/m57-090

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

Dense, felt-like growth of aerial mycelium ofMelampsora lini(Pers.) Lév. was obtained when surface-sterilized, rust-infected cotyledons of flax were put on a modified Knop medium, containing fresh, ripe coconut milk, sucrose, and Difco Bacto-Agar. The mycelium remained fully dependent on the living host tissue, but could easily be collected free from host material in quantities sufficient for respiration and small scale chemical studies. Slight modification of the method allowed production of appreciable quantities of uredospores free from contaminating microorganisms.

ISSN:0008-4166    

DOI:10.1139/m57-091

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

A newAchromobacterspecies which decomposed 2,4-dichlorophenoxyacetic acid (2,4-D), apparently to small molecules, was isolated from a soil treated with successive closes of the herbicide. The organism grew poorly or not at all on common laboratory media in the presence or absence of 2,4-D. Investigation of its carbon, nitrogen, mineral, and vitamin requirements in agar containing 2,4-D showed that the best growth stimulants were the dicarboxylic acids of the tricarboxylic acid cycle, bicarbonate, formate, urea, andL-histidine. Calcium or magnesium and probably iron were required for maximum growth. Some aryloxy acids, phenolic compounds, and an ester were tested for their ability to replace 2,4-D as growth substrate or to inhibit growth in the presence of 2, 4-D, and it was found that the ethyl ester of 2,4-D and chlorophenolic substances were most toxic. Only 2-methyl-4-chlorophenoxyacetic acid (MCPA) and less readily, 4-chlorophenoxyacetic acid, phenoxyacetic acid, and resorcinol could substitute for 2,4-D. Good cell multiplication and herbicide decomposition were obtained in an aerated mineral salts medium containing 2,4-D, yeast extract, and 0.005 ML-malic acid. Maximum growth (ca. 109cells/ml.) occurred in 4 to 5 days and 2,4-D decomposition was essentially complete in 6 to 7 days. Resting cells were able to oxidize 2,4-D, MCPA, 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), and 2,4-dichlorophenol (2,4-DCP) and to release 94% of the 2,4-D chlorine as chloride. High concentrations of yeast extract caused growing cells to accumulate 2,4-DCP.

ISSN:0008-4166    

DOI:10.1139/m57-092

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

Studies of the microbial conversion of progesterone to Δ1,4-androstadiene-3,17-dione byStreptomyces lavendulaeand to 16α-hydroxyprogesterone byStreptomycessp. ATCC 11,009 have shown that a lag in metabolism of the steroid occurs when the progesterone is added to washed cells of these organisms grown in a medium containing soybean meal, glucose, and calcium carbonate. No lag was observed when the cells were grown in this medium supplemented with a trace of progesterone. Addition to the cell suspensions of sufficient quantities of streptomycin sulphate, viomycin sulphate, dihydrostreptomycin sulphate, neomycin B sulphate, or tetracycline hydrochloride (to give a concentration of 10 μg. per ml.) coincident with the addition of the progesterone resulted in complete inhibition of steroid oxidation. When addition of the antibiotics was delayed until 12 hours after addition of the progesterone or the cells were grown in a medium containing a trace of progesterone, practically no inhibition was observed. These experiments suggest that the enzymes formed in these two streptomycetes which carry out the transformation of progesterone are adaptive in origin.

ISSN:0008-4166    

DOI:10.1139/m57-093

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

A paper chromatographic method suitable for identification of the small amounts of coumarins and phenolic acids present in the uredospores of wheat stem rust was developed. By the use of the circular technique and a combination of three different solvent systems an adequate separation of all the substances was achieved. A preliminary development of the chromatogram with a solvent in which the test compounds were non-mobile facilitated identification and avoided the need for extensive preliminary fractionation of the extracts.Using this method the following compounds were identified in spore extracts: coumarin, umbelliferone, daphnetin, aesculetin,p-hydroxybenzoic acid, vanillic acid, protocatechuic acid,o-coumaric acid,p-coumaric acid, ferulic acid, and caffeic acid; coumarin,p-hydroxybenzoic acid, vanillic acid, protocatechuic acid,o-coumaric acid, and ferulic acid were also present as glycosides; in addition scopoletin, gallic acid, syringic acid, and sinapic acid were detected after hydrolysis and are assumed to be present only in a bound form.In order to obtain some information about the role of these substances in the physiology of wheat stem rust, uredospores were germinated by being floated en masse on dilute aqueous solutions. Of the compounds tested, indoleacetic acid, coumarin,o-coumaric acid, protocatechuic acid, umbelliferone, and daphnetin gave a marked stimulation of germination at concentrations of 10–200 μg./ml. Caffeic acid, vanillic acid,p-hydroxybenzoic acid, ferulic acid, and ferulic acid β-glucoside had little effect or were strongly inhibitory.The stimulation of germination is attributed to the counteraction of a self-inhibitor released from the spores, and the possible significance of the compounds on the physiology of the rust and the host–parasite relationship is discussed.

ISSN:0008-4166    

DOI:10.1139/m57-094

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

The use of beta-propiolactone (BPL) for the destruction of infectivity of influenza, mumps, and poliomyelitis virus suspensions has been investigated. It was found that: (1) the infectivity was destroyed more rapidly as the pH was increased from 6 to 8, and (2) the hemagglutination titers of influenza and mumps virus suspensions were most stable to BPL treatment at pH 7. Since the pH of the medium decreases with the hydrolysis of BPL, it was found desirable to use a buffered medium for BPL treatment. Influenza and mumps vaccines prepared with BPL have been lyophilized successfully for stable storage by the addition of 5% arginine or 5% peptone prior to lyophilization. Vaccines prepared from chick allantoic fluid, which had not been frozen, required dialysis of the virus concentrate prior to BPL treatment. Reaction conditions have been selected which render the virus suspensions non infective while preserving most of thein vitroserological activity. Antigenicity tests of the virus suspensions treated with BPL are discussed in the second section (II) of this paper.

ISSN:0008-4166    

DOI:10.1139/m57-095

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

An investigation has been made of the antigenicity of influenza virus suspensions rendered noninfective with beta-propiolactone (BPL). By treatment with BPL under various conditions, influenza vaccines could be prepared which were antigenic as indicated by production of specific antibody response in mice and guinea pigs. These vaccines were also immunizing as evidenced by their capacity to protect mice against challenge with live virus.

ISSN:0008-4166    

DOI:10.1139/m57-096

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

The ability of effective and ineffective strains of rhizobia to degrade 6-phosphogluconate directly to pyruvate and the metabolic activity of these strains in relation to the glycolytic, and hexose monophosphate oxidative pathways of carbohydrate break down were studied. No distinct relationship between metabolic activity, pyruvate production, and effectiveness was obtained although it was found that effective strains of rhizobia oxidized succinate more rapidly than ineffective strains. The organisms possess certain enzymes involved in glycolysis as well as alternate pathways for hexose phosphate utilization via the oxidative route.

ISSN:0008-4166    

DOI:10.1139/m57-097

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

Isolated cases and family epidemics of mouse favus were found in the lower St. Lawrence Valley, especially in the Kamouraska County. The specific agent of mouse favus was repeatedly isolated from animals (mice, cats, dogs, fox) and children and adults (smooth skin and scalp). The mouse is the normal host of the dermatophyte. Cats and dogs acquire the disease from mice and transmit it to man.Cultures of the isolated dermatophytes resembled in all respects Quincke's α-Pilz (Achorion quinckeanum). The formation of elongate microconidia and pedicellate, spindle-shaped, thick-walled macroconidia with pointed tips was observed in slide cultures made with wort agar (Difco). These morphological features place the fungus in the genusMicrosporum. Therefore, the specific agent of lavus of mice should be named forthwith.Microsporum quinckeanum.

ISSN:0008-4166    

DOI:10.1139/m57-098

出版商:NRC Research Press    

年代:1957

数据来源: NRC