摘要:

Several miniaturized microbiological techniques were devised. These techniques were combined with multiple-inoculation methods for rapid characterization ofStaphylococcus aureusstrains isolated from turkey products. These procedures are applicable to a variety of other ecological investigations; they result in substantial savings of space, material, labor, and time.

ISSN:0008-4166    

DOI:10.1139/m72-251

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The nomenclature of the genusSalmonellaand the biochemical reactions given by members of this genus are reviewed. It was concluded that the three-species system is the best solution to the problem of nomenclature within the genusSalmonella. Methods are outlined by which members of the three species ofSalmonella(Salmonella cholerae-suis,Salmonella typhi, andSalmonella enteritidis) can be differentiated from each other, définitions are given for each of the species, and recommendations are made as regards usage of the system of nomenclature.

ISSN:0008-4166    

DOI:10.1139/m72-252

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The effect of liquid nitrogen storage on intragenic recombination in strains of the anther smutUstilago violaceamutant at theuvs-1 locus was analyzed. Such low temperature storage did not affect significantly recombination at this locus, and it appears to be a useful method of preserving genetic strains.

ISSN:0008-4166    

DOI:10.1139/m72-253

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

When washed suspensions ofPseudomonas aeruginosaare placed in salt solutions, the cells shrink rapidly and then swell more slowly as salt and water enter them. The rate of swelling is increased by EDTA and its calcium chelate. The effect of EDTA is antagonized by diamines; the effect of the calcium chelate by carboxylic acids. The relative effects of EDTA and the calcium chelate differ in different salts which suggests different sites of action. The evidence indicates that EDTA does not act by chelating calcium or magnesium in the membrane of these cells but that its two nitrogen atoms combine by electrostatic forces with anionic sites, and the chelate, in which the nitrogen atoms are bound to calcium, combines by the same forces to cationic sites. Barium, strontium, and magnesium chelates are inactive.

ISSN:0008-4166    

DOI:10.1139/m72-254

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The utilization of singleL-amino acids as sole source of carbon and nitrogen by bacteria was studied and was found to be very common and widely distributed over many genera. Field soil contained large numbers of such bacteria; 7.7–79.2% of the colony count obtained on nutrient agar could be achieved by using a single amino acid as sole carbon and nitrogen source. Twenty taxonomically known bacteria which could use one or more amino acids were examined for the range of amino acids over which they could grow. Organisms which grew on one amino acid usually grew on several. Some ecological aspects of these findings are discussed.

ISSN:0008-4166    

DOI:10.1139/m72-255

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Phagocytosis of toxic spores ofClostridium botulinumtype A by human polymorphonuclear leukocytes as revealed by electron microscopy involves engulfment on contact and rapid inclusion into phagocytic vacuoles, followed by a rather slow process of spore germination within the next 8 h. Once germinated, spores appear to be degraded intra-phagocytically almost instantaneously. No outgrowth of spores into vegetative cells was observed either within the leukocytes or outside. Pathogenicity ofC.botulinumspores seems to depend on germination of spores within the phagocyte, degradation of germinated spores, and release of spore-bound toxin into body fluids; thus causing potentially fatal botulism poisoning.

ISSN:0008-4166    

DOI:10.1139/m72-256

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Fluorometric methods have been used for the determination of the momentary levels of some glycolytic intermediates and adenylates during the development ofAspergillus nigerin fermenter culture and also in a medium which allows vegetative growth but not conidiation. During periods of active glycolysis the levels of the hexose monophosphates were low while the other intermediates were high; during periods of low glycolysis this pattern was reversed. The interrelations of the momentary concentrations of the intermediates indicated that the phosphofructokinase step may be a control site in glycolysis inAspergillus niger.

ISSN:0008-4166    

DOI:10.1139/m72-257

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The technique of lyophilization has been used to prepare β-lysin that can be stored in aliquots at ordinary refrigeration temperatures. It has permitted the determinations of environmental ionic strength, pH, and magnesium ion concentration favoring bactericidal and lytic activities of this agent. Killing of cells as well as lysis of protoplasts ofBacillus subtiliswere favored in environments not more than 0.2 nor less than 0.15 in ionic strength. Of the environmental pH tested (6.0, 7.0, and 7.5), lysis of cells and of protoplasts was most efficient at pH 7.5, whereas bactericidal action was relatively unaffected in this range. The effectiveness of bactericidal action and of lysis of protoplasts decreased as the amount of Mg2+in the environment increased.

ISSN:0008-4166    

DOI:10.1139/m72-258

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The release of intracellular materials from the psychrophileBacillus psychrophilusat temperatures from 5 to 50C was studied as a means of indicating possible membrane damage. RNA, protein, carbohydrate, and inorganic phosphate, but not DNA was found to leak from the cells. The rate of leakage increased as the temperature was raised. It is shown that the amount of leakage at 40C in the length of time required for 90% death could be sustained at 25C with little or no death. Therefore, death of this psychrophile at supramaximal temperatures cannot be attributed to loss of membrane integrity with resultant loss of intracellular material. Electron micrographs of the cells demonstrated a trilaminar cell wall which becomes severely damaged during heating. The damage is irreversible at 40C and may contribute to heat-induced death.

ISSN:0008-4166    

DOI:10.1139/m72-259

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The net yields of sterols in cultures ofFusarium oxysporumSchl. em Sny. et Hans, were reduced 44% by an inhibitor of cholesterol synthesis (ICS) obtained from mitochondria of starved rats' livers and 63% by glycerol. The yields of sterols were determined by weighing and the incorporation of radioactive carbon from sodium acetate-2-14C into digitonide precipitates was assayed by liquid scintillation. The major sterol was identified as ergosterol.

ISSN:0008-4166    

DOI:10.1139/m72-260

出版商:NRC Research Press    

年代:1972

数据来源: NRC