摘要:

The altered growth of a pneumococcal mutant containing markerM, which confers ability to utilize mannitol, and a modifier gene is reported. The modifier gene is closely linked to theMgene and imposes a requirement for growth in 0.4% glucose before growth in mannitol medium. The tentative position of theMgene of pneumococcus isery-r str-r M sul-rd.

ISSN:0008-4166    

DOI:10.1139/m75-170

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

The process of sporulation was studied inBacillus stearothermophilus. A medium is described that supports good growth and sporulation of the organism. In this medium, which contains glucose, salts, and amino acids, acetate starts to accumulate before any of the glucose is catabolized. Enzymes of the tricarboxylic acid cycle are present at all times during growth and sporulation and are found in dormant spores. As the glucose in the culture is consumed, acetate rapidly increases and the pH of the medium drops. The acetate rapidly disappears during sporulation and the pH rises. Dipicolinic acid appears during sporulation and several key-enzyme activities fluctuate in a characteristic pattern.

ISSN:0008-4166    

DOI:10.1139/m75-171

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Mutation with ultraviolet light and chemical mutagens yielded strains with auxotrophic and streptomycin-resistance markers. These were used to show the existence of genetic recombination inStreptomycesspecies 3022aand to construct a linkage map for 17 marker loci.

ISSN:0008-4166    

DOI:10.1139/m75-172

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

The effects on plant growth of "bacterial fertilizers" prepared fromAzotobacterspp. and phosphate-solubilizing bacteria ("phosphobacteria") have been the subject of much controversy. Cases where no plant-growth stimulation occurred may often be accounted for by the failure to establish the bacterial inocula in the rhizosphere.Three factors that may influence inocula establishment, i.e. soil fertility, manuring, and interactions betweenAzotobacterand "phosphobacteria," were examined in pot experiments, designed for statistical analysis, in two neutral–alkaline soils, using lavender plants (Lavandula spicaL.). During the experiments the numbers ofAzotobacterand "phosphobacteria" were counted. Dry weights of roots and shoots were recorded after 16 weeks of growth.At the end of the experiments there were always moreAzotobacterand "phosphobacteria" in the rhizospheres when plants were inoculated with both groups of organisms together than when they were inoculated singly. Addition of 2% farmyard manure to the richer soil enhanced this effect.Plant growth was greatest when seedlings were inoculated with bothAzotobacterand the "phosphobacteria."

ISSN:0008-4166    

DOI:10.1139/m75-173

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

From a defective-lysogenicProteus mirabilisstrain we isolated several clones differing in the pattern of their growth on agar plates. Using electron microscopy we have shown some of the selected clones to be efficient in producing mirabilicin D-52 after UV induction, while other clones produced defective mirabilicin polysheaths and polycores. Clones producing polysheaths and polycores can be detected electron microscopically only, since these defective particles are biologically inactive.

ISSN:0008-4166    

DOI:10.1139/m75-174

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

The HEPES–saline–albumin–gelatin (HSAG) diluent found optimal for agglutination of fowl erythrocytes by rubella virus antigen is also optimal for agglutination of trypsin-treated human group O cells. Albumins from different commercial sources, however, can have varying inhibitory effects on rubella hemagglutination titers. This can have a significant effect on the hemagglutination-inhibition test since antibody titers measured by this procedure are related to the amount of antigen used.

ISSN:0008-4166    

DOI:10.1139/m75-175

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Four products derived fromStaphylococcus aureuscultures were partially purified and tested for inhibitory activity against staphylococcal phage. Phage inhibition, a specific stable phenomenon, was concentration dependent. All inhibitory products contained carbohydrate and amino acids, the most active (phage 73 lysate product) having a high carbohydrate content. Galactose, glucosamine, five or six amino acids, and possibly 3-O-methylglucose and a uronic acid were found as components in all active preparations. However, the exact nature of the active material remains undetermined.

ISSN:0008-4166    

DOI:10.1139/m75-176

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

A strain ofPseudomonas aeruginosa, which was resistant to 400 μg/ml of chloramphenicol (CM), was isolated. The generation time of the resistant strain was the same in the presence or absence of CM and similar to that of the parent strain growing in the absence of chloramphenicol. Resistance is eliminated by treatment with acridine dyes, mitomycin C, and sodium dodecyl sulfate, suggesting that resistance may be expressed by a plasmid. The resistant strain does not produce the pigment pyocyanine and the addition of pyocyanine to this strain eliminates the resistance factor. A strain sensitive to CM was isolated. This strain does not produce the enzyme acetyl CoA: chloramphenicol transacetylase whereas the resistant strain does. The sensitive strain accumulates14C-CM at a greater rate and to a greater extent than the resistant strain grown in the presence of CM. The results suggest that the resistant strain inactivates CM by acetylation and, in addition, develops a "permeability" barrier towards chloramphenicol.

ISSN:0008-4166    

DOI:10.1139/m75-177

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Spores ofBacillus cereusT prepared in a glucose – yeast extract – salts broth germinated inL-alanine or more rapidly inL-alanine plus inosine or adenosine. The nucleosides alone were not germinative. Inosine was shown to produce no pregerminative changes in spores that prepared them for more rapid germination later inL-alanine. Experiments which measured the interaction of nucleosides, heat shock, andD-alanine on germination rates suggested that nucleosides may potentiateL-alanine-induced germination by causing discrimination againstD-alanine at theL-alanine binding site(s) in the spore.D-Alanine is germinative when used with inosine probably because ofL-alanine formation by alanine racemase. Heat shock, a prerequisite toD-alanine plus inosine-induced germination, may facilitate entry of inosine into the spore in amounts needed to discriminate againstD-alanine.

ISSN:0008-4166    

DOI:10.1139/m75-178

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Ten species of non-pathogenicNeisseriawere grown in simple defined liquid media containing amino acids, biotin, nicotinic acid, calcium pantothenate, ferrous sulfate, magnesium sulfate, and potassium phosphate. Two of theseNeisseriawere induced to grow with glutamic acid as the carbon and nitrogen source. The remaining eightNeisseriagrew in glutamic acid medium supplemented with from one to four additional amino acids, lactate, or lactate and glucose. A strain ofN.flavescensgrew in the absence of added growth factors whereas the remaining nine species ofNeisseriarequired either biotin or nicotinic acid; pantothenate was required by two and was stimulatory for three of these species. Use of carbohydrates by the non-pathogenicNeisseriain synthetic medium was tested. Two strains failed to use any of the 14 carbohydrates tested; one strain used only glucose; the remaining seven strains used fructose, glucose, maltose, and sucrose to varying degrees.

ISSN:0008-4166    

DOI:10.1139/m75-179

出版商:NRC Research Press    

年代:1975

数据来源: NRC