摘要:

Binary-encoded descriptions of 85 named cultures (mostly of soil origin) and of 15 unnamed soil isolates were analyzed by a two-stage principal component procedure including the condensation of the data in terms of grouping of tests and of cultures. This procedure also allowed an evaluation of the discriminative importance of the tests used. Nine clusters of cultures were found by use of a centroid clustering procedure in the space defined by the five leading principal component (P.C.) vectors, which collectively accounted for 54% of original variance. The clusters of item-points representing the cultures were plotted in the dimensions defined by the first and second P.C. vectors providing a geometrical model by which their relationships could be visualized. These P.C. vectors could be interpreted in terms of 31 important discriminative tests (many of which were concerned with the utilization of carbon compounds) from the total of 98 tests used. Fifteen clusters of tests were found as a result of Adansonian R analysis, and 37 clusters of cultures found by means of Adansonian Q analysis. The groupings of the isolates by the Q analysis and the P.C. analysis were compatible although there was some geometrical distortion. To supplement personal decisions on the acceptability of automatically derived clusterings, additional analyses were performed to investigate the homogeneity, relative sizes, and spatial relationships of the clusters of organisms found. In general, results of taxonomic interest were concordant with those of other workers, especially in respect of the generaArthrobacter,Rhizobium, andPseudomonas. It was concluded that the bacteriological and the numerical methods used would be appropriate for comparative study of heterotrophic bacterial populations from rhizosphere and corresponding soil environments.

ISSN:0008-4166    

DOI:10.1139/m69-026

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

An inhibitory substance(s) has been found in S-30 fractions fromProteus vulgariswhich prevented anEscherichia coliB cell-free system from incorporating a mixture of14C-amino acids,L-phenylalanine-14C, orL-lysine-14C into protein, as directed by natural messenger ribonucleic acid, polyuridylic acid, or polyadenylic acid respectively. Similar results were obtained when the inhibitor was isolated from S-100 fractions by using dialysis, concentration of the dialysate by flash evaporation, hydrolysis, evaporation to dryness, dissolution to the original volume in distilled water, and neutralization. The effect of the inhibitor on the various individual reactions involved in protein synthesis was examined. No effect was found on the activation of amino acids as determined by the formation ofL-phenylalanine-14C hydroxamate isolated chromatographically or by adenosine triphosphate – pyrophosphate exchange. Also no inhibition ofL-phenylalanine-14C attachment to transfer ribonucleic acid occurred. However, ribosome-dependent reactions were markedly inhibited. The mechanism of action of the inhibitor appeared to be the prevention of binding of phenylalanyl-transfer ribonucleic acid to the ribosomes.

ISSN:0008-4166    

DOI:10.1139/m69-027

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

A toxic strain ofAphanizomenon flos-aquaewas isolated and cultured in a defined medium (ASM-1). This strain fixes nitrogen, has a pH optimum of 7.5, and has maximum growth rates at 5000 lux and 26 °C. Phosphorus levels of 1.0 μMreadily supported populations of 1 × 105 cells/ml with stimulation of growth evident at a concentration of 0.1 μMP. Tris is inhibitory to growth of this alga at concentrations above 2.5 mM.Toxin production is related to age of culture, temperature, and light intensity but not nitrogen source.Intraperitoneal injection of toxic extracts intoFundulus heteroclitus,Cyprinodon variegatus, and white mice gave a LD100of 0.5 mg/kg, 0.5 mg/kg, and 8 mg/kg, respectively. Assays withNotemigonus crysoleucasandBosmina longirostrisindicate that the toxin from naturally occurring bloom populations (1 × 106 cells/ml), if released all at once, would be capable of killing certain species of fish and microcrustaceans.Daphnia catawba, however, was much more resistant to toxin (LD100 = 1.0 mg/ml) while cyclopoid copepods, ostracods, and chydorid cladocerans were completely unaffected by toxin concentrations of 2.0 mg/ml. The possible ecological significance of this toxic alga in relation to fish kills is also discussed.

ISSN:0008-4166    

DOI:10.1139/m69-028

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

The sulfatase ofCephalosporium acremoniumis regulated by exogenous sulfur compounds, repressed in cells in 0.02 Msulfate, and derepressed in 5 × 10−4 Msulfate. Organic sulfur sources, such as cysteine, homocysteine, and methionine, derepress the enzyme in varying degrees while the latter amino acid is also required for maximum synthesis of the antibiotics cephalosporin C and penicillin N. Sulfatase-repressed cells transferred from sulfate to methionine-containing medium produce a high level of these antibiotics in the culture medium and a proportionate derepression of the sulfatase. Cycloheximide inhibits sulfatase derepression in cultures transferred from sulfate to methionine medium while having negligible effect on antibiotic synthesis. Mutant cultures ofC.acremonium, with an increased potential to synthesize sulfur-containing antibiotics, have decreased ability to degrade methionine for other cellular requirements and sulfatase derepression is proportionately increased. The sulfatase is thus regulated by the biosynthesis of cephalosporin C and penicillin N at the expense of sulfur-containing compounds required for other cellular processes.

ISSN:0008-4166    

DOI:10.1139/m69-029

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Because the lipoic acid activating systems catalyze reactions which are formally expected for an energy-dependent transport system, an examination of their cellular distribution was made. The pyruvate: lipoate oxidoreductase (acceptor-acetylating) complex (E.C. No. 1.2.4.1) and the lipoic acid activating system in bothS.faecalis10 C1 andE.coli(Crookes strain) were found entirely in the membrane supernatant solution preparations (soluble enzymes). NADH oxidase was located in the solubilized membrane preparation, suggesting that the membrane preparations were representative, and glucose-6-phosphate dehydrogenase was found almost exclusively in the soluble fraction. It appears unlikely from distribution studies that the enzyme(s) of the lipoic acid activating system are involved in the transport of the lipoic acid into the cell.

ISSN:0008-4166    

DOI:10.1139/m69-030

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Certain properties of the tRNA methylases from hamster tumor tissue induced by adenovirus-12, hamster liver, and hamster connective tissue are described. The three enzyme extracts are shown to possess different substrate specificities, different responses to the presence of ammonia ions, different pH optima, and different stabilities on storage.Evidence indicates that the increased tRNA methylase in tumor extracts is not related to the T-antigen found in tumors induced by adenovirus-12.

ISSN:0008-4166    

DOI:10.1139/m69-031

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

The olfactory bulb was studied in the normal and infected adult hibernating squirrel (Citellus lateralis). Severe damage developed in the olfactory bulbs ofallthe squirrels which were inoculated into the axillary adipose pad with coxsackievirus B-3. The earliest changes were observed in the small blood vessels and the large neurons. The blood vessels showed endothelial swelling but no virus antigen. Most of the large neurons showed the presence of virus antigen by the direct fluorescent antibody method. Concurrently, the virus was recovered from the olfactory bulb at a relatively high titer (LD5010−5.25), but only traces of virus had remained in the blood. In the small neurons (the cellule nervose piccole and the granule cells) the viral antigen appeared later, by which time the large neurons had undergone complete lysis. The granule cells retained the normal morphology throughout the infection. The cellule nervose piccole showed reversible changes, and the glia cells were unaffected.

ISSN:0008-4166    

DOI:10.1139/m69-032

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

The immunological response was studied in the adult hibernating squirrel (Citellus lateralis) infected with coxsackievirus B-3. The complement activity was considerably reduced between the 4th and 9th day of infection, but was restored to the normal level by the 11th day. The neutralizing antibody was first detected in the blood on the fourth day, reached an average ND50of 10−2.62on the seventh day after inoculation, and remained at this level.Gamma globulin was demonstrated in the infected olfactory bulb by the direct fluorescent antibody method on the seventh day after inoculation. The specific fluorescence appeared as a surface staining of the infected granule cells, cellule nervose piccole, and within numerous inflammatory cells. On staining with methyl green – pyronin these cells resembled the antibody-producing cells in the spleen.A sequential correlation existed between the development and appearance of the gamma-globulin-producing cells in the spleen and the olfactory bulb which indicated that the lymphoid cells infiltrated into and contributed to the tissue destruction in the olfactory bulb of the infected squirrel.

ISSN:0008-4166    

DOI:10.1139/m69-033

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

For use in the hemagglutination–inhibition test, influenza virus antigens in the form of (a) untreated and inactivated allantoic fluids and (b) untreated and inactivated purified virus suspensions were compared. The inactivation procedures used were formaldehyde treatment and gamma irradiation. It was found that there was no significant difference in the potency and specificity of the purified virus antigens but that the formaldehyde-treated allantoic fluids lost potency during this process. The inactivated antigens can be lyophilized for stable storage and, after reconstitution, can be used in the diagnostic laboratory without risk of infection or interference with isolation procedures. For ease and speed of treatment, gamma irradiation is superior to treatment with formaldehyde.

ISSN:0008-4166    

DOI:10.1139/m69-034

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Washed cells of a strain ofPseudomonas aeruginosarapidly decrease in size when they are put in salt solutions and then upon incubation increase in size. In the presence of streptomycin (10 μg/ml) this increase is followed by a decrease but only if ammonia has been assimilated by the cells in the presence of an oxidizable substrate. The extent of the decrease caused by streptomycin is proportional to the amount of ammonia assimilated and also the concentration of the salt solution. Chlortetracycline (0.02 μg/ml), chloramphenicol (1.0 μg/ml), and cycloserine (10 μg/ml) completely inhibit the streptomycin effect when added before or after ammonia assimilation is complete.

ISSN:0008-4166    

DOI:10.1139/m69-035

出版商:NRC Research Press    

年代:1969

数据来源: NRC