摘要:

Growth ofcaseinate utilizinglactic streptococci in media with sodium caseinate as the nitrogen source was retarded by sodium acetate (40 mg./ml.) and by sodium citrate (10 mg./ml.). The inhibition caused by citrate was relieved by calcium or magnesium while that caused by acetate was relieved by calcium. In media with acid hydrolyzed casein as the nitrogen source, growth was inhibited in the presence of sodium citrate (10 mg./ml.) or disodium ethylene diamine tetraacetate (0.004 mg./ml.) but this inhibition was overcome by the addition of either calcium or magnesium. It appears, therefore, that these divalent ions were not required merely for activation of proteases produced by the organisms.

ISSN:0008-4166    

DOI:10.1139/m57-043

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

Two strains isolated from two cases of recurrent polyarthritis are discussed. The organisms are antigenically related and according to morphology and growth requirements they are considered to belong to the group of pleuropneumonia-like organisms.

ISSN:0008-4166    

DOI:10.1139/m57-044

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

The cells ofNavicula pelliculosa(Bréb.) Hilse, when grown in media which contained 3.5, 8.3, and 34.0 mg. Si per liter, reproduced with generation (doubling) times of 20.4, 13.7, and 13.1 hours respectively. The degree of silicification of the cells in each culture initially fell with increasing population. After exponential growth had ceased, this value varied between 0.8 × 10−9and 2.2 × 10−9 mg. Si per cell, depending on the amount of silicon originally present in the medium and on the age of the culture. When placed in a fresh silicate solution, the cells took up additional silicate with increases in silicon content of 50%, 90%, and 15%, respectively. Silica (SiO2) may represent from 4% to 22% of the dry weight of the cells. The average thickness of the frustules has been calculated to range between 200 and 600 Å.

ISSN:0008-4166    

DOI:10.1139/m57-045

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

Further studies of the phase variation ofRickettsia burnetidescribed by Stoker (12, 13) and Stoker and Fiset (14) are reported. Animals (guinea pigs and rabbits) infected or vaccinated (with killed purified suspensions) with either Phase 1 or Phase 2 ofR.burneti(Nine Mile and Christie strains) develop antibodies that are detectable very early (within 21 days after inoculation) when their sera are tested with antigens in Phase 2. Except for the group of guinea pigs vaccinated with killed purified suspensions of Nine Mile Phase 2, all the animals also produce antibodies against the Phase 1 strains but these appear much later than the anti-Phase 2 antibodies. It is believed thatR.burnetiwhen reverting from the non-reactive Phase 1 to the reactive Phase 2 through egg adaptation loses some of its surface antigens.

ISSN:0008-4166    

DOI:10.1139/m57-046

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

The bacteria isolated from the air in a series of aeroplane flights, over Canada, Alaska, and the Arctic Ocean, are discussed. All bacteria are forms commonly found in the soil and include species ofFlavobacterium,Achromobacterium,Pseudomonas,Corynebacterium,Micrococcus,Sarcina, andBacillus. An attempt is made to correlate the types of organisms found with the air masses. Air that had received no recontamination for some time tended to show death of organisms in a certain order. The first to be reduced in numbers were the Gram-negative rods, then the Gram-positive rods, followed by the micrococci, and finally the sporeformers.

ISSN:0008-4166    

DOI:10.1139/m57-047

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

Two return flights were made across the Atlantic Ocean from Montreal to London, England, and aerobiological samples were taken at intervals throughout the flights. This publication deals with the bacteria isolated during these flights. The bacteria were found to be very much like those found over land and included the following genera:Pseudomonas,Flavobacterium,Achromobacter,Corynebacterium,Micrococcus,Sarcina, andBacillus.

ISSN:0008-4166    

DOI:10.1139/m57-048

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

Cells ofPseudomonas salinariacontain a cysteine desulphydrase which, like the corresponding enzyme ofEscherichia coli, decomposes cysteine to hydrogen sulphide, pyruvic acid, and ammonia in the presence of pyridoxal phosphate. Unlike the enzyme ofE.coli, the enzyme ofP.salinariarequires high concentrations of potassium chloride for maximum activity. The enzyme is present in cells grown in media containing 15 to 30% sodium chloride.

ISSN:0008-4166    

DOI:10.1139/m57-049

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

A strain ofGliocladiumsp. and a strain ofUstilago maydisproduced approximately 400 μg./ml. of extracellular lysine in shaken Erlenmeyer flasks. InU.maydisgrowth media, most of the extracellular lysine, arginine, and histidine is in the free form. Metabolic studies show the lysine to be formed during early growth, concurrent with the formation of most of the extracellular organic nitrogen. The extracellular organic nitrogen and lysine is used during a late growth surge in experiments showing high lysine concentrations but not in those showing low lysine concentrations.None of the compounds tested as precursors or intermediates resulted in an increased concentration of extracellular lysine.

ISSN:0008-4166    

DOI:10.1139/m57-050

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

Spores ofAlternaria,Aspergillus,Fusarium,Gliocladium,Penicillium, andPestalotia, budding vegetative cells ofUstilago, and uredospores ofPuccinia graminis,P.helianthi, andMelampsora liniwere lyophilized using several techniques and various conditions. The best percentage survival of the lyophilized spores and cells was obtained when the initial freezing of the spore suspensions was just low enough to keep the suspension solid until evaporative freezing conditions were reached. Freezing to very low temperatures was unnecessary. Conditions permitting fast warming of the frozen suspension resulted in increased survival. A preliminary degassing treatment greatly enhanced percentage germination, as did the conditioning of the spores in a moist atmosphere immediately after the opening of the tubes for revival of the organisms.

ISSN:0008-4166    

DOI:10.1139/m57-051

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

The ability of strains of lactic streptococci to utilize unhydrolyzed sodium caseinate as the nitrogen source in an otherwise complete, chemically denned medium did not appear to be related to their minimal amino acid requirements. Sodium caseinate had a sparing effect on the requirement for some amino acids of some strains of streptococci that did not use caseinate, but the amino acids spared varied with the strain. However, leucine, isoleucine, methionine, and valine appeared to be essential for this group of organisms in the presence or absence of sodium caseinate.

ISSN:0008-4166    

DOI:10.1139/m57-052

出版商:NRC Research Press    

年代:1957

数据来源: NRC