摘要:

The effects of 20, 25, or 30 °C incubation temperatures for dilution-plates and of five plating media (Ohio Agricultural Experiment Station Medium (OAES), Liftman"s crystal-violet agar, dextrose-peptone agar, soil-extract agar, and glucose-nitrate soil-extract agar) on total numbers and types of fungi isolated from two soils (sugar beet or corn cropped) by a soil-dilution plate method were determined. The data revealed that significant differences existed among the three variables as well as their interactions. Although numbers of colonies of fungi isolated were not affected significantly, the types of fungi (number of individual genera) isolated were significantly greater in sugar beet than in corn cropped soils. In nearly all instances, the greatest total number and types of fungi were isolated at temperatures of 20 or 25 °C. Although each medium appeared to favor one or more groups of fungi, the overall frequency and distribution of fungi was essentially the same on all media. On the basis of its transparency, total number and types of fungi isolated, the elimination of bacteria and actinomycetes, and its restriction of rapidly growing fungi, the OAES medium was deemed the most suitable for use in the soil-dilution plate method.

ISSN:0008-4166    

DOI:10.1139/m63-100

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

not available

ISSN:0008-4166    

DOI:10.1139/m63-101

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

The inducible enzyme, D-alIose-6-kinase, has been purified 25-fold from cell-free extracts ofAerobacler aerogenes. The enzyme, which was free of D-phosphoall-ose isomerase activity, had an optimum pH at 6.5, and, at 0 °C, was most stable between 6.5 and 7.5. A requirement for Mg++was demonstrated, Ca++ions being only 37% as effective as Mg++at a concentration of 0.005M. The activation by 0.005MMgCl2was reduced 50% by 0.01MVersene. Of 23 sugars and related compounds tested, the kinase phosphorylated D-allose (100), D-glucose (20), D-ribose (6.3), D-galactose (3.5), and allitol (2.8). TheKmfor D-allose as substrate was 0.98X10"3M. CTP is about 50% and UTP about 43% as effective as ATP as phosphate donors. The enzyme is sensitive to Hg++ions and sulp-hydryl reagents.The product of the reaction of the enzyme with D-allose and ATP was identified as D-allose-6-phosphate by determination of acid-labile phosphate, by periodate oxidation studies, and by chromatography of the dephosphorylated sugar moiety.

ISSN:0008-4166    

DOI:10.1139/m63-102

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

The properties of the respiratory (dissimilatory) form of nitrate reductase and the assimilatory form of the same enzyme fromE. colicells were investigated. It was shown that each enzyme form was attached to cellular "particulate" material. Although each enzyme is reported in the literature to differ in its electron donor requirements, no differential assay could be established.Immunochemical investigations showed that the specific antibody against the highly purified respiratory form of enzyme could cross react with the assimilatory enzyme. Induction studies indicated that the increase in activity of the assimilatory form of nitrate reductase paralleled the increase in antigenic activity. These similarities between the respiratory and assimilatory form of nitrate reductase would indicate that few, if any, differences exist between the two forms.

ISSN:0008-4166    

DOI:10.1139/m63-103

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

The possible utility of static culture conditions for sporulation studies was evaluated. The effects of a series of potential amino acid antagonists on the growth and sporulation of a strain ofBacillus cereusin a defined medium were compared under both static and shaken culture conditions. A randomly picked series of 24 analogues was observed to produce all of the possible effects (no inhibition of growth or sporulation, inhibition of growth, inhibition of sporulation, delay of growth and sporulation) with no important qualitative differences between the shaken and static systems. The commonly accepted premise that shaken cultures must be used for sporulation studies has nogeneralvalidity; the simpler technique of static culture may have great value for observation of the developmental stages of sporulation.

ISSN:0008-4166    

DOI:10.1139/m63-104

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Pseudomonas perfectomarinusreleased nitrogen fiom nitrate in media containing a variety of amino acids, pyruvate, or urea, but only if these minimal media were supplemented with glucose or, preferably, citrate. L-Arabinose (and to a lesser degree, D-arabinose) served as electron donor in combination with glucose or citrate, whereas other sugars did not. Asparagine, however, was the most effective oxidizable substrate tested and was the only test compound supporting denitrification without supplementary glucose or citrate. Mano-metric experiments revealed that adapted resting cells liberated nitrogen very rapidly with asparagine but less rapidly with citrate. Furthermore, cell-free extracts of adapted bacteria denitrified nitrate when provided with these substrates. Flavine mononucleotide was more effective as a stimulatory cofactor for denitrification than flavine adenine dinucleotide in whole-cell experiments, but not with cell-free extracts. Experiments with dialyzed cell-free extracts revealed that the enzymes which oxidized asparagine and citrate (or actually isocitrate) were linked with triphosphopyridine nucleotide. Additional experiments with cell-free extracts revealed that oxidation of reduced triphosphopyridine nucleotide was enzymatically linked with flavine mononucleotide.

ISSN:0008-4166    

DOI:10.1139/m63-105

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Pseudomonas aeruginosawas grown on a basal medium composed of glycerol, L-alanine, and salts. The utilization of glycerol and alanine for the biosynthesis of pyocyanine was measured by labeling them with C14, and the utilization of other compounds added to the basal medium was measured by the isotope competition technique. The carbon atoms of pyocyanine were derived more from glycerol than from L-alanine, even when the phosphate concentration of the medium was changed. Supplementary compounds which supplied more of the carbon atoms in pyocyanine than in cell material were fructose, ribose, calcium a-keto gluconate, glucose, glyceric acid, iV-acetyl glucosamine, and quinic and shikimic acids. Quin-ic acid was metabolized to a greater extent, and supplied more of the carbon atoms in pyocyanine and cell material than shikimic acid tested under similar conditions. When quinic acid and glucose were added together to the basal medium they were equally good precursors of pyocyanine, but glucose was used less specifically, supplying more of the carbon in cell material as well. The ratio for the carbon atoms entering a-hydroxyphenazine from carbons 1 plus 3 of glycerol as compared to carbon 2 of glycerol was compatible with that expected, assuming that glycerol was used to synthesize shikimic acid and that 2 molecules of shikimic acid (or a closely related compound which could be derived from quinic acid) condensed to form the aromatic rings of pyocyanine. The other findings were compatible with this hypothesis.

ISSN:0008-4166    

DOI:10.1139/m63-106

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Fourteen bacterial strains representing eight so-called species of phytopathogenic xanthomonads were tested for lysogeny both before and after treatments known to induce phage development in lysogenic bacteria. Only a single temperate phage, of restricted host range, was found. Evidence suggestive of defective lysogeny was found in a number of cases.Strain P165,Xanthomonas campestris, when treated with antibiotic Mitomycin C at a concentration of 0.1,ug/ml in nutrient broth, produced phage particles active on strain P12S,X. campestris. No other sensitive strains were found among the 81 tested, representing 22 species ofXanthomonas. This phage (P165/P125) produced small turbid plaques, 0.6 mm to 0.8 mm in diameter, with indefinite margins. Evidence for the lysogenization of P125 strain by this phage was found. Clear plaques were sometimes found in lawns of lysogenized cells of P12S. These were presumably derived from phage mutants with increased virulence. When examined under the electron microscope, the phage particles were semispherical, approximately 65 m/x in diameter with rudimentary tails.

ISSN:0008-4166    

DOI:10.1139/m63-107

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Strains ofPasteurella pestis, grown on Fildes" or sulphite agar, or on a selective medium, at 30 °C formed microcolonies containing from 20 to 50 bacilli in 5 to 6 hours. These microcolonies were treated with aP. pestisbacteriophage and subsequently incubated at 18 °C. Lytic changes in the microcolonies began about 3 hours after application of the phage and the microcolonies were largely destroyed 2 hours later. The phage lysed microcolonies of several strains ofPasteurella pseudotuberculosis, two ofEscherichia coli, and one ofShigella dysenteriaeat 30 °C but at 18 °C it was active only onE. coli K12 C600besidesP. pestis. The susceptibleE. colistrain did not growonthe selective medium, which could therefore be used to increase the specificity of the test. Methods for performing this test in practice are discussed. The technique would allowP. pestisto be identified about 10 hours after inoculation of an agar plate with infected material. Although slower than a fluorescent antibody reaction performed on a direct smear of infected material, this phage-lysis procedure may find a place as a semirapid confirmatory test forP. pestis.

ISSN:0008-4166    

DOI:10.1139/m63-108

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Studies were made comparing aspartase synthesis byAerobacter aerogentsgrown in the presence and in the absence of glucose, and with or without agitation. It was observed that when a sufficient initial glucose concentration was employed, enzyme synthesis was not resumed to maximum levels even after complete utilization of the sugar. At a lower glucose concentration, however, synthesis did occur, suggesting that the specific repressor metabolite(s) produced from the glucose was not accumulated to inhibitory concentrations after the sugar was metabolized. A difference between stationary and aerobic (shaken) cultures was noted, perhaps affording a suitable system for investigating the molecular mechanism of glucose repression.

ISSN:0008-4166    

DOI:10.1139/m63-109

出版商:NRC Research Press    

年代:1963

数据来源: NRC