摘要:

A primary site of sparsomycin attack inEscherichia coliappears to be inhibition of synthesis of protein, which occurs at concentrations of sparsomycin that do not affect DNA or RNA synthesis. Sparsomycin interferes with the normal excretion of amino acids byE.coli. Some cross-resistance was observed between a culture resistant to sparsomycin and cultures resistant to other inhibitors of protein synthesis.

ISSN:0008-4166    

DOI:10.1139/m66-085

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

A method is described for determining the localization of alkaline phosphatase in the cells ofE.coliB with the electron microscope. Enzyme activity, determined by deposition of inorganic phosphate, is located in the exterior layer of the cell wall.

ISSN:0008-4166    

DOI:10.1139/m66-086

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

An examination of colonies of 51 strains ofActinobacillus malleigrown on a complex agar medium containing heart infusion broth, yeast extract, glucose, and glycerol indicated a high degree of heterogeneity in respect of colonial morphology both within and between strains. A strain possessing high virulence for hamsters (I.P. LD50for hamsters < 20 cells) was almost completely homogeneous, and colonies of this strain, when viewed microscopically using an oblique lighting technique, were buff in color and had a dull, slightly rough surface and even edges with a slightly cross-hatched appearance. The designation "typical" was given to colonies of this type. Other colonial types designated as "smooth", "intermediate", and "dense, yellow" were isolated from subcultures of this strain. Additional colony types were found upon examination of other strains; these include a "wrinkled variant and several forms of granular and rough colonies. Prolonged incubation of stationary broth cultures of several strains led to the establishment of new colonial types in several strains tested, and ""wrinkled" and "white, opaque, glistening" colonies were isolated from cultures inoculated with "typical" and "intermediate" forms. The relationship of these findings to the earlier work of Mochida is discussed.

ISSN:0008-4166    

DOI:10.1139/m66-087

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

A simple, chemically defined liquid medium containing phosphate buffer, magnesium and ferrous sulfates, glucose, and tribasic ammonium citrate supported excellent growth of a virulent strain ofActinobacillus mallei. When growth was measured turbidimetrically, a comparison of the rates of growth in media containing different initial concentrations of hydrogen ion (pH 6.3 and 6.6), phosphate buffer (0.05 Mand 0.08 M), glucose (0.05 Mand 0.10 M), and ammonium citrate (0.01 Mand 0.02 M) indicated that the lower concentration of phosphate, glucose, and citrate and pH 6.3 favored early growth. The higher concentration of glucose favored an increase in cell mass during the early stationary phase unaccompanied by a comparable increase in viable cells. The highest viable cell count was attained in a medium containing 0,08 MKH2PO4–K2HPCO4, 0.05 Mglucose, 0.02 Mammonium citrate, 0.000005 MFe++, and 0.001 MMg++after 45 hours incubation, during which time the viable cell concentration rose from 1.6 × 107to 1.5 × 1010/ml.

ISSN:0008-4166    

DOI:10.1139/m66-088

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

Twenty-three substrains representing colonial variants of 11 strains ofActinabacillus malleiwere examined for their ability to attack carbohydrates. Tests conducted in a basal liquid complex medium, containing yeast extract and proteose peptone No. 3 with bromcresol purple as indicator, showed that all strains tested produced acid from arabinose, glucose, fructose, galactose, mannose, and trehalose, while five substrains gave positive results with lactose, one with sucrose, and two with maltose. Eosin methylene blue agar of the same basal composition gave positive results for most of the strains grown on arabinose, glucose, fructose, galactose, mannose, and trehalose, and negative results for all strains grown on xylose, lactose, sucrose, and maltose. In a chemically defined medium containing ammonium chloride as nitrogen source and bromcresol purple as indicator, acid was produced by eight substrains of five of these strains from glucose, galactose, mannose, and trehalose, and by several strains from fructose and sucrose. The ability of these five selected strains to utilize carbohydrates as sole carbon sources for growth was tested in a chemically defined medium containing ammonium citrate as nitrogen source. All strains were able to grow on glucose, galactose, mannose, and trehalose, and most were able to grow on fructose. Arabinose, xylose, lactose, sucrose, and maltose did not support the growth of any of the strains tested.

ISSN:0008-4166    

DOI:10.1139/m66-089

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

Growth ofActinobacillus malleiwas inhibited by kanamycin; the minimal inhibitory concentration in a complex medium was 1.25 μg/ml and in a chemically defined medium 5 μg/ml. Higher concentrations of kanamycin had a pronounced bactericidal effect. When a suspension of cells containing 5 × 107viable cells/ml was incubated in the presence of 20 μg/ml of kanamycin in a chemically defined medium, complete sterilization resulted after 6 hours. Cells irradiated with ultraviolet light were grown in complex or supplemental minimal media, washed, and exposed to 20 μg/ml of kanamycin in minimal medium for 4 hours. Auxotrophic mutants with requirements for tryptophane, phenylalanine, proline, and uracil were detected among the survivors of kanamycin treatment. After treatment with 0.01 Mnitrous acid and growth in minimal medium supplemented with amino acids, cells were washed and then exposed to kanamycin in minimal medium. The proportion of autotrophs among the survivors varied from 1.3 to 75%. Mutants with requirements for each of the following amino acids were identified: methionine, methionine or cystine, arginine, leucine, tryptophane, histidme, and proline, with methionine-requiring mutants predominating. Exposure of mixtures of prototrophs and uracil-dependent and methionine-dependent auxotrophs to 20 μg/ml of kanamycin for 4 hours resulted in approximately 700- and 300-fold increases, respectively, in the ratio of auxotrophs to prototrophs.

ISSN:0008-4166    

DOI:10.1139/m66-090

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

Characteristics of the hemadsorbing enteric (HADEN) virus were studied in bovine embryonic kidney (BEK) cell cultures. The virus was found to be resistant to both ethyl ether and sodium desoxycbolate. The growth of the virus was not inhibited by 5-iodo-2′-deoxyuridine, but guanidine hydrochloride completely inhibited its multiplication. Virus infectivity was not affected by heating at 56 C for 4 hours. No loss in titer occurred after a 30-minute exposure to pH 2.0; however, very little infective virus remained after a 2-hour exposure to this acidity. Of nine cell culture systems tested, HADEN virus produced cytopathic changes only in BEK and bovine lymph node cultures. Cytological studies on infected cells were conducted using fluorescent antibody, acridine orange, and inclusion body staining techniques. The fluorescent antibody staining first revealed viral antigen in the cytoplasm (6 hours) followed by nuclear invasion, which was pronounced by 48 hours. Acridine orange staining showed an increase in cytoplasmic ribonucleic acid staining 72 hours postinfection. The virus produced type A intranuclear inclusions which were fully formed by 72 hours. Electron micrographs of negatively stained virus preparations showed spherical particles approximately 28 mμ in diameter with a capsomeric structure. It is suggested that HADEN virus is a member of the bovine enterovirus group.

ISSN:0008-4166    

DOI:10.1139/m66-091

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

Studies were undertaken to elucidate factors which promote growth ofArthrobacter citremon nutrient agar at 37 °C. It was shown that nutrient agar was not actively inhibitory toA.citreusat this temperature. In nutrient medium, neither yeast extract, Casamino acids, nor fermentable sugars promoted growth at 37 °C. However, the ash of trypticase soy broth when added to nutrient broth supported growth at 37 °C. Na+and K+were found to have a similar growth-promoting effect. Mg++, Ca++, and Fe+++had no activity while Mn++was inhibitory. Buffered cell-suspensions ofA.citreusshowed a higher rate of leakage of ultraviolet-absorbing (260 mμ) materials at 37 than at 25°C. It appears that cell lysis and release of intracellular materials occur at 37 °C. Data from paper chromatographic and tracer techniques suggested that these released substances are nucleotides.

ISSN:0008-4166    

DOI:10.1139/m66-092

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

Cultures ofStaphylococcus aureuswere grown in the presence of five different antimetabolites (5-fluorodeoxyuridine, aminopterin, 8-azaguanine, mitomycm-C, 5-fluorouracil) active against ceil walls and (or) nucleic acids. Fluorescence microscopy of smears stained with acridine orange revealed reddish and green cells in both treated and untreated cultures. There were less than 20% of reddish cells in untreated cultures and more than 40% in treated cultures. Treated cultures contained fewer viable organisms. All antimetabolites except mitomycin-C produced a diminution in the nucleic acids, chemically determined as percentage of dry weight of bacteria. Only 5-fluorouracil increased the RNA/DNA ratio. However, with ultraviolet microscopy at 260 mμ wavelength the absorption of reddish cells is much higher than that of the green cells, which, at the cellular level, seemed to indicate a greater nucleic acid content. With ultraviolet or with fluorescence microscopy we have obtained similar evidence of the cellular heterogeneity produced by antimetabolites in bacterial populations.

ISSN:0008-4166    

DOI:10.1139/m66-093

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

A microcolony method of measuring antibiotic sensitivity requiring 4 hours incubation, was adapted to testing of organisms obtained directly from swabs, urines, and blood cultures. The results of the "direct" 4-hour test were compared with those obtained by prolonging incubation to 20 hours and with results obtained by carrying Out similar tests on the individual organisms isolated in pure culture ("indirect" tests). All of 12 urine samples and 6 infected blood specimens proved suitable for testing but only 35 of 68 swabs were suitable. Unequivocal results in direct tests were obtained in 94.3% of 4-hour tests and 95% of 20-hour tests. The result of the 4-hour direct test differed from that of the 20-hour direct test on 2.8% of occasions, and from those of the 4-hour indirect and the 20-hour indirect test on more than 5% of occasions. Discrepancies occurred about twice as often with staphylococci as with enterobacteria.

ISSN:0008-4166    

DOI:10.1139/m66-094

出版商:NRC Research Press    

年代:1966

数据来源: NRC