摘要:

A Gram-negative rod isolated from flounder eggs grows in the temperature range 0–19 °C. At 21 °C there is no growth and at higher temperatures death occurs rapidly in, both seawater and seawater growth medium. After death, the cells lyse, as shown by decreased turbidity and the release of ultraviolet-absorbing substances. Lysis of non-growing cultures initiated at 25 °C can be retarded but not halted by lowering the temperature to 5 °C or 15 °C, temperatures at which cells not previously exposed to 25 °C remain viable and do not lyse. Lysis was not inhibited by a number of metabolic inhibitors, or by spermine. A small percentage of the total hexosamine is released by lysing cells, but the greatest change noted was the disappearance of most of the lipid phosphorus, probably representing the lipids of the cytoplasmic membrane. The breakdown of phosphatidyl ethanolamine, the major phospholipid in the cells, was demonstrated. Isolated cell envelopes also lyse at 25 °C, losing lipid phosphorus in the process. No evidence was found for a soluble lytic enzyme.

ISSN:0008-4166    

DOI:10.1139/m64-106

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

Lysostaphin, an antibiotic that is unique inasmuch as it lyses all strains ofStaphylococcus aureus, has been tested against 252 strains obtained from clinical sources. The clinical isolates were phage typed and tested for in vitro susceptibility to lysostaphin and seven other antistaphylococcal antibiotics.The resistant strains, found generally in phage groups I, III, and Insensitive, were most susceptible to vancomycin, lysostaphin, ristocetin, and kanamycin. The antibiotics least effective were penicillin G, tetracycline, phenethicillin, and erythromycin. As an attempt to quantitate the susceptibility of various clinical strains of 5.S.aureusto lysostaphin, a "lysostaphin index" was devised in which, by an arbitrary criterion, the susceptibility of a clinical isolate was related to the sensitivity ofS.aureus, strain FDA 209P. It was found that all isolates were lysed by lysostaphin.

ISSN:0008-4166    

DOI:10.1139/m64-107

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

A.aerogenesproduces an inducible enzyme system that converts allose to fructose-6-phosphate. The first step is a phosphorylation to yield allose-6-phos-phate. Evidence is presented that indicates an isomerase transforms allose-6-phosphate to allulose-6-phosphate which is subsequently converted to fructose-6-phosphate by a 3-epimerase.

ISSN:0008-4166    

DOI:10.1139/m64-108

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

A marine bacterium, isolated by an enrichment technique, is able to utilize choline as the sole carbon and nitrogen source in a medium containing various salts. The morphological and biochemical characteristics of the organism indicate that it is a new species. Substrate feeding coupled with culture filtrate analyses indicate that choline is metabolized as follows: choline → betaine → dimethylglycine + formaldehyde → sarcosine + formaldehyde → serine → pyruvate + ammonia without transmethylation being involved. This pathway has not previously been reported for other bacteria or for animal tissues.

ISSN:0008-4166    

DOI:10.1139/m64-109

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

The microbial degradation of 2,2-dichloropropionic acid (dalapon) in five soils was observed under greenhouse and laboratory conditions. Oat plant bioassays revealed that under greenhouse conditions (28 °C) dalapon persisted only 4–8 days in a muck soil, 8–16 days in loam and silty clay loam soils, 16–32 days in sandy loam soil, and 32–64 days in a silty clay soil. An enrichment technique was used to isolate microorganisms effective in the degradation of dalapon from each soil. Although differences in microbial populations among the five soils examined were evident, each soil possessed one or more organisms capable of rapidly degrading dalapon under pure culture conditions. Dalapon degradation by effective microorganisms was affected by organic matter level, pH, cation exchange capacity, and aeration.

ISSN:0008-4166    

DOI:10.1139/m64-110

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

The specificity and sensitivity of a fluorescent antibody technique applied to growing microcolonies has been investigated using serotypes ofEscherichia coliresponsible for infective enteritis as a model. Microcolonies of 10E.coliserotypes showed bright fluorescence when treated with homologous conjugated antiserum but no fluorescence when treated with heterologous conjugated antisera. Microcolonies of Enterobacteriaceae strains of other genera or ofE.colistrains not associated with infective enteritis showed no fluorescence when treated with conjugated antisera prepared against the enteritis serotypes.Experiments with artificially infected faecal suspensions showed that the sensitivity of the microcolony technique was approximately one hundred times greater than that of the direct smear method. A number of other advantages and possible disadvantages of the microcolony technique are discussed and its usefulness in epidemiological work is suggested.

ISSN:0008-4166    

DOI:10.1139/m64-111

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

L-Methionine-methyl-C14orL-serine-3-C14was added in substrate amount to a medium containingD-quinic acid, glycerol,L-alanine, and salts.Pseudomonas aeruginosawas grown on this medium, and the pyocyanine synthesized by the organism was isolated and degraded to give an estimate of radioactivity in the N-methyl carbon atoms. The methyl carbon atoms of methionine added to the medium supplied 66% of the N-methyl carbon atoms of pyocyanine and were not incorporated to any extent into the rest of the pyocyanine molecule. This was true even though this strain ofP.aeruginosadid not require an exogenous supply of methionine to synthesize pyocyanine. The addition of unlabelled serine to the medium did not decrease the incorporation of the methyl carbon atoms of methionine into the N-methyl carbon atoms of pyocyanine. The labelled carbon atoms of serine-3-C14were incorporated to a lesser extent and less specifically into the N-methyl carbon atoms of pyocyanine than were the methyl carbon atoms of methionine.

ISSN:0008-4166    

DOI:10.1139/m64-112

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

Cultures ofAgrobacterium tumefaciensgrown on a synthetic medium containing glucose plus a pyrimidine produced a pyrimidine riboside with unusual chemical properties. This substance was isolated in crystalline form and identified as 5-ribosyluracil (pseudouridine) on the basis of data obtained from ion exchange and paper chromatography, electrophoresis, ultraviolet and infrared spectrophotometry, color reactions, melting point, elementary analysis, hydrazinolysis, and periodate oxidation followed by bromine treatment.

ISSN:0008-4166    

DOI:10.1139/m64-113

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

Aerosols ofEscherichia coliB were subjected to 250 kv X-rays. It was found that maximal X-ray damage occurred at 70 to 80% relative humidity (R.H.). At these R.H. values only the water bound directly to cell macromolecules remains, and if the water layers were increased by using higher humidities, X-ray damage decreased. Also, at R.H. levels below 70% a sharp decrease in the sensitivity of the cells to the radiation occurred. Several chemicals known to protect cells against desiccation, ultraviolet, and X-ray damage were examined and of thesei-inositol proved the most successful. The difference in the protective ability of these various compounds indicated that some protect cells against desiccation damage by retaining water, others by replacing bound-water molecules in macromolecular structure but those retaining water will not protect against X-rays. The results suggest that the physical removal or ionization of a strategic bound-water molecule by X-rays causes most of the cell deaths rather than ionizations occurring in the free water as the presence of the latter appears to offer cells a measure of protection.

ISSN:0008-4166    

DOI:10.1139/m64-114

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

Forty glucosamine derivatives were tested for antimicrobial properties. Five of these were shown to possess significant activity against a number of bacteria, yeasts, and fungi in vitro. These were 5-bromosalicylidene-D-glucosamine (No. 103), cinnamylidene-D-glucosamine (No. 112), 3,5-dibromosalicylidene-D-glucosamine (No. 104), 3,5-dibromosalicylidene-D-glucosamine oxime (No. 130), and 3-nitro-5-chlorosalicylidene-D-glucosamine (No. 119). The acute LD50of each compound in mice was approximately 200, 400, 400, 600, and > 1000 mg/kg for 119, 104, 130, 103, and 112, respectively. Studies on mode of action indicated that 103, 104, and 130 may interfere with glucosamine metabolism inCandida albicans; ultrastructural changes in this organism were also produced by these three derivatives. Numbers 103, 104, 119, and 112 were phosphorylated by yeast hexokinase, and all except 112 depressed the rate of glycolysis in a cell-free extract.

ISSN:0008-4166    

DOI:10.1139/m64-115

出版商:NRC Research Press    

年代:1964

数据来源: NRC