摘要:

Forty-live cultures of thermophilic aerobic sporeforming bacilli isolated from samples of herring stickwater have been identified as strains ofBacillus stearothermophilusDonk.

ISSN:0008-4166    

DOI:10.1139/m57-103

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

The estimation of the numbers of aerobic thermophilic bacteria by the plate count method was found to be greatly influenced by the composition of the diluent and by its temperature. A satisfactory diluent consisted of 0.8% KCl inM/200 pH 7.2 potassium phosphate buffer. The need of maintaining the temperature at 37 °C. and using the special diluent was demonstrated with pure cultures and with mixed cultures obtained by the enrichment procedure. In some cases, the new condition of plating gave counts 100 times those obtained by conventional means. Cultures which were almost completely free of spores were used in determining the optimum plating conditions.

ISSN:0008-4166    

DOI:10.1139/m57-104

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

L-Erythrulose was dissimulated anaerobically byAerobacter aerogenesPRL R4 producing acetic acid, formic acid, succinic acid, glycolic acid, ethanol, erythritol, hydrogen, carbon dioxide, and traces of acetone and 2,3-butanediol.D-Erythrose andD-threose were also dissimilated to form the same products. Resting cells metabolized the tetroses, whereas cell-free preparations were inactive. Phosphorylation of the tetroses was not found with cell-free preparations.

ISSN:0008-4166    

DOI:10.1139/m57-105

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

Antifungal preparations were obtained from cultures ofStreplomycesPRL 1642 by solvent extraction of the solids collected after the pH was adjusted to 3.5. The active factor, named amidomycin, was purified by repeated crystallization from aqueous ethanol or petrol (b.p. 60°–80 °C.) to give stable, colorless, optically active needles, m.p. 192 °C.Amidomycin suspended in agar media retarded the growth of many filamentous fungi and noticeably inhibited the plant pathogensUstilago maydis,Ustilago trebouxii, as well as the human pathogen,Hormodendrum pedrosoi. It also inhibited the germination of uredospores ofPuccinia graminisat low concentrations. Certain yeasts were completely inhibited by small concentrations of amidomycin; the quantity required was affected by the number of cells in the inoculum.None of the bacteria examined was inhibited by this antibiotic. At certain concentrations it was lethal toCandida albicansas determined by the inability of previously exposed and washed cells to grow on nutrient agar.Although a few isolated colonies ofCandida albicansusually developed on plates containing approximately double the concentration required to inhibit growth of the inoculum streak, serial transfer of progeny from such colonies onto agar containing amidomycin did not produce cultures having progressively increasing resistance.Two degradation products of amidomycin, D(–)-valine and 3,6-diisopropyl-2,5-diketomorpholine, are inactive.

ISSN:0008-4166    

DOI:10.1139/m57-106

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

Cystine, cysteinesulphinic acid (CSA), and other closely related sulphur-containing amino acids inhibited growth ofEscherichia coli113-3, particularly in aerobic conditions. The cystine inhibition was completely prevented by aspartic acid, partially reversed by pantothenic acid or β-alanine and slightly reversed by lysine or thiamine. The inhibitory effect of CSA was completely or partially reversed by aspartic acid, lysine, glutamic acid, proline, ornithine, or homoserine. Aspartic acid and glutamic acid appeared to reverse the inhibition competitively while lysine seemed to reverse the inhibition in a noncompetitive manner. Reversal of the inhibitory effect of relatively high concentrations of CSA by lysine was not complete, however, unless methionine was also present. Possible mechanisms of the cystine and CSA inhibition are discussed.

ISSN:0008-4166    

DOI:10.1139/m57-107

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

Employing physical and chemical methods eight antigenic fractions were isolated fromHistoplasma capsulatumas determined by complement fixation technique. Two of the fractions were found to cross-react with coccidioidal antisera, two with coccidioidal andBlastomycesantisera, one withBlastomycesantisera, while the remaining three displayed specificity by reacting withHistoplasmaantisera only. Some evidence is presented to indicate that the isolated fractions are antigenically distinct.

ISSN:0008-4166    

DOI:10.1139/m57-108

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

An extracellular hydrolase, specific for agar, was prepared fromPseudomonas atlantica. This enzyme hydrolyzed commercial American Difco agar, New Zealand Davis agar, and extracts fromGelidium cartilagineum,G.coulteri,G.pristoides,Pterocladia pyramidale,Gracilaria confervoides, andSuhria vittata. Extracts from algae which contain carrageenin as structural polysaccharide were not hydrolyzed. The products of enzymic hydrolysis were sugars withRgalactosoof 1.35, 0.75, 0.32, 0.12, 0.07. These sugars constituted a homologous series of oligosaccharides of which neoagarobiose was the basic unit.

ISSN:0008-4166    

DOI:10.1139/m57-109

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

When added to aqueous suspensions ofPseudomonas aeruginosa(Schroeter) Migula, an organism pathogenic to grasshoppers in the laboratory, a number of test agents allowed no survival after 24 hours' desiccation in air; others, 0.001 to 10%; 5% sucrose, 30%. A combination of 1% casein, 5% sucrose, and 1% granular mucin supported the growth of the bacteria and gave 29% survival after 24 hours' drying. Survival rates in this investigation compare favorably to those obtained by other investigators when drying was carried out under complex conditions, such as freeze-drying.

ISSN:0008-4166    

DOI:10.1139/m57-110

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

The purification and certain properties ofL-asparagine deamidase ofBacillus coagulansandBacillus stearothermophilusare described. Maximum enzyme activity was obtained at 55 °C. over a pH range of 7.5 to 8.5. The purified deamidase hyclrolyzed theL-isomer of asparagine quantitatively to aspartic acid and ammonia and did not attack theD-isomer.D-Asparagine inhibited the hydrolysis of theL-isomer. TheKmfor the inhibition reaction was found to be 1.87 × 10−2 M. The enzyme did not catalyze transamidation or hydroxylamine transfer reactions. Enzyme activity was inhibited by N-ethylmaleimide andp-chloromercuribenzoate. The inhibition by these agents was reversed by glutathione. In the absence of substrate the deamidase of both organisms was relatively heat labile at 55 °C. The heat lability of this enzyme is discussed in relation to the heat stability of other enzyme systems of thermophilic microorganisms.

ISSN:0008-4166    

DOI:10.1139/m57-111

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

A variation in plaque type ofBacillus megateriumphage ψ16Bcl is described. The host culture for this study was an asporogenic strain ofB.megateriumNo. 1. The investigation revealed that the cause of the variation is lysogenization, which gives rise to two variants calledM-1 andM-2. Some of their characteristics are described. The results suggest that the parent-type phage perpetuates itself during lytic cycles of reproduction, and gives rise to variant phage when it lysogenizes the host.

ISSN:0008-4166    

DOI:10.1139/m57-112

出版商:NRC Research Press    

年代:1957

数据来源: NRC