摘要:

Manometric studies were carried out on the metabolic activity of different rhizosphere and non-rhizosphere soils from the greenhouse and the field. Oxygen consumption was distinctly greater with the rhizosphere soils. On the addition of substrates such as casamino acids or a mixture of carbohydrates and organic acids, greater oxygen uptake again occurred with the rhizosphere soils and was particularly striking with the amino acids. Chromatographic studies of extracts of rhizosphere and non-rhizosphere soil incubated with casamino acids suggested that certain amino acids such as arginine, proline, and tyrosine may be preferentially utilized in the rhizosphere.

ISSN:0008-4166    

DOI:10.1139/m57-074

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

Three approaches were used in attempting to improve the method of isolatingSpirillum sputigenumfrom the human oral cavity:(1) attempts to induce spreading surface growth;(2) selective inhibition of interfering organisms;(3) adjustment of oxidation–reduction potentials.Five of eight strains ofSpirillum sputigenumgrew as spreading surface films on a blood agar medium in which the base was a veal heart infusion. Increase in the amount of spread could not be induced by varying the agar content of the medium. Sodium lauryl sulphate (0.01%) was found to have a marked inhibitory effect on the human oral flora but did not inhibitSpirillum sputigenum.A method of recording potentials of the surface layer of solidified media using a gold foil electrode is described. Changes in potential of the surface layer of a number of media during reduction in a Brewer jar are recorded. Media in which the potential was rapidly reduced supported growth ofSpirillum sputigenum. Of several reducing substances added to media, sheep's serum was the most effective in accelerating a drop in potential. Using a medium compounded of veal heart infusion, sodium lauryl sulphate, and sheep's serum,Spirillum sputigenumwas recovered in pure culture from 16 out of 21 samples of gingival scrapings.

ISSN:0008-4166    

DOI:10.1139/m57-075

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

Labelled non-viscous cells ofMicrococcus halodenitrificanswere obtained in media containing P32and 2 Msodium chloride and their growth then followed in salt concentrations ranging from 0.55 M, the lower limit of growth, to 3 M. At concentrations of 0.7 Mand above, cells remained non-viscous and only traces of extracellular nucleic acids (NA) could be detected. At lower concentrations of salt, cells became viscous and the amount of extracellular NA increased as the concentration decreased. The distribution of P32indicated that the source of the extracellular NA was intracellular. At the salt concentrations studied, the loss of NA was prevented by the addition of calcium or magnesium ions. However, sodium chloride seemed necessary to maintain the cell wall ofM.halodenitrificansand the effect was supplemented by divalent ions. It is suggested that this may explain the salt requirement of this organism and possibly that of other halophilic bacteria.

ISSN:0008-4166    

DOI:10.1139/m57-076

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

A newly discovered bacterial disease of larvae ofMalacosoma pluviale(Dyar) (Lep.) is caused by infection of the gut with a large, motile, sporeforming bacterium,Bacillussp., that increases in size before sporulation and bears the spore without bulging. It has not been cultivated. The bacterium invades the host with the food and multiplies in the midgut and foregut, producing changes in the pH and causing dysentery in the host. Sporulation occurs in the gut and both rods and spores are passed in the faeces and spread the disease. The infected larva loses its appetite, regurgitates excessively, produces wet faeces, decreases markedly in length, and dies in a characteristic, short, dry, mummified condition after about a week. Small ingested doses of spores initiate infection in laboratory populations ofM.pluvialein all instars.M.americana(F.) also is susceptible to the disease butM.disstriaHbn. is resistant, only a few individuals dying from it.

ISSN:0008-4166    

DOI:10.1139/m57-077

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

The numbers of bacteria, with actinomycetes, were found to be significantly correlated with organic matter in field plots treated annually with straw, and straw with phosphate, followed by the ploughed-in crop of each plot. The treatment with straw significantly increased the numbers of microorganisms as well as the organic matter content in the plots during 3 years.

ISSN:0008-4166    

DOI:10.1139/m57-078

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

An investigation has been made of methods to remove the non-specific complement-fixing components which sometimes occur in the routine preparation of virus soluble antigens. It was found possible to remove such components from influenza soluble antigens by (1) centrifugation for 1 hour at 36,000 gor (2) treatment of the antigen with 10% Norit, followed by uf. filtration. With mumps soluble antigen, this purification was accomplished by (1) centrifugation as above or (2) heating the antigen for 30 minutes at 70 °C. at pH 9, followed by centrifugation at 9000 g.

ISSN:0008-4166    

DOI:10.1139/m57-079

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

The cells of 19 species of bacteria, actinomyces, and yeasts were analyzed for protein and essential amino acids. A rapid quantitative method for amino acid determination using one-dimensional paper chromatography was developed. The cellular protein from all species contained relatively high concentrations of lysine, somewhat lower concentrations of tryptophan and threonine, and very low concentrations of methionine. All of the 10 essential amino acids were found in each species tested, although individual differences in the relative and absolute amounts were observed.

ISSN:0008-4166    

DOI:10.1139/m57-080

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

An unusual form of colloidal sulphur is precipitated when dilute solutions of cysteine hydrochloride and ferric ammonium citrate are mixed and autoclaved. The intravenous injection of this relatively insoluble particulate material is associated with a retardation in the progress of tuberculosis in guinea pigs and rabbits, and a change in the histology of the tubercle to a more proliferative and less destructive form. A considerable therapeutic effect is seen when infected rabbits are treated with a combination of streptomycin and this form of colloidal sulphur.

ISSN:0008-4166    

DOI:10.1139/m57-081

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

Dipicolinic acid constitutes 12% of the dry weight of spores ofBacillus cereusvar.terminalis.Following a heat-shock treatment at 65 °C. glucose is oxidized by the ungerminated spores, the amount of oxidation increasing with time of heating from 10 μl. per hour at zero time to 230 μl. per hour after heating for 60 minutes. Also during this treatment there is an increase in the amount of dipicolinic acid released from 2% of the total at zero time to 12.5% of the total after 60 minutes.The possible relationship between this material and the enzymes of resting spores is discussed.

ISSN:0008-4166    

DOI:10.1139/m57-082

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

2-Ketogluconate, gluconate, and fructose specifically labeled with C14were fermented byLeuconostoc mesenteroides. Radioactive carbon dioxide was recovered from the fermentation of the C-1 labeled substrates, while methyl labeled lactic acid was recovered from the C-6 labeled compounds. The results indicate that the metabolism of these compounds and that previously reported for glucose are similar. This organism can be used to degrade these compounds for the determination of C14distribution.

ISSN:0008-4166    

DOI:10.1139/m57-083

出版商:NRC Research Press    

年代:1957

数据来源: NRC