摘要:

The growth ofEscherichia coliATCC 9637 in a basal synthetic medium was very similar in cultures incubated at 35, 37, 40, and 42 °C. The inclusion in the medium of copper at concentrations of 0.1 and 0.2 μg/ml resulted in a decrease in the growth rate at each of these temperatures; the higher the temperature, the greater the decrease. Copper caused a decrease in the growth rate ofE.coliin the medium sterilized by filtration as well as in that sterilized by autoclaving. However, in the medium sterilized by heat there were alternate periods in which the optical density (O.D.) of culture increased and periods during which no increase in O.D. occurred. Decreases of 50% or more in the numbers of viable cells occurred in conjunction with the plateaus in the O.D. of the cultures. A greater delay in the initiation of growth occurred in both the copper-free and the copper-containing media sterilized by heat than in the corresponding medium sterilized by filtration; the longer the exposure of the medium to heat during the sterilization process, the greater the delay in the initiation of growth. Several theories are presented and discussed as possible explanations of the experimental data obtained.

ISSN:0008-4166    

DOI:10.1139/m67-176

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The adverse effects of hyperbaric oxygenation on the reproduction and survival of bacteria are augmented by increased hydrostatic pressure. Different bacterial species differ considerably in their tolerance of increased hydrostatic pressure as well as for increased partial pressure of oxygen. Although their generation times may be lengthened and their reproduction rates retarded by increased pressures, most species of well-known bacteria are able to grow at hydrostatic pressures as high as 200–400 atm. In closed systems at 1 atm, certain aerobic bacteria grow well, or sometimes better, in nutrient media in which the partial pressure of oxygen is 5 to 10 times higher than that in the normal atmosphere (-Po2ca. 0.2 atm, equivalent to a dissolved oxygen content of ca. 7 μg/ml), but such increased concentrations of oxygen (35–70 μg/ml) are injurious at substantially increased hydrostatic pressures, for example, 5–25 atm.Escherichia coli,Bacillus subtilis,Bacillus megaterium,Pseudomonas enalia,Pseudomonas perfectomarinus, andSerratia marinorubrawere sterilized within a day or two by compression to 100 atm in media having a dissolved oxygen content of 35 μg/ml. All six species thrived at 100 atm in nutrient media having an initial oxygen content of 7 μg/ml and they grew well in media with an oxygen content of 35 μg/ml at 1 atm.

ISSN:0008-4166    

DOI:10.1139/m67-177

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

When spores ofGlugea fumiferanaewere treated with chlorides of alkali metals at pH 10.8 at 28 ± 1 °C, the polar filament was extruded by almost 70% of them within 40 min. The effect of pH varied with the different metals, the effective range being greatest for Cs, and becoming progressively narrower for Rb, K, Na, and Li. Although KCN and NaF are normally metabolic inhibitors, both were effective in stimulating extrusion of polar filaments. Previous treatment of the spores with either AgNO3or HgCl2inhibited the stimulatory effect of CsCl, but CuSO4had no inhibitory effect. Calcium chloride interfered with the stimulatory effect of CsCl, but the effect became less as the concentration of CsCl increased.p-Chloromercuriphenylsulfonate, salyrgan, and physostigmine were all ineffective in inhibiting extrusion of polar filaments.

ISSN:0008-4166    

DOI:10.1139/m67-178

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Escherichia coliandPseudomonas aeruginosawere grown at several temperatures ranging from 0° to 37 °C and assayed at each temperature forL-serine dehydratase activity. The relationship between enzymatic activity and growth temperature is quite different for the mesophile and psychrophile. In addition, the stimulatory effect of natural plant lecithin upon serine deamination was different for each organism, suggesting that there is either a difference in permeability or that this substance has a more direct role in enzymic activity. Also included are data confirming the results of other workers.

ISSN:0008-4166    

DOI:10.1139/m67-179

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The effect of atrazine (2-chloro-4-ethylamino-6-isopropylamino-.s-triazine) on growth ofSclerotium rolfsiiandTrichoderma viridewas studied in liquid culture. The fungi were grown in Czapek solution containing 0, 8, 20, 40, and 80 μg of the herbicide per milliliter, and growth responses were measured at intervals of 3–5 days after inoculation. Mycelial dry weight ofS.rolfsiiwas little affected at concentrations below 40 μg/ml, but was decreased at the higher concentrations. Total mycelium produced byT.viridewas greater with all atrazine treatments than in the control. ForS.rolfsii, the efficiency of utilization (economic coefficient) of glucose, inorganic P, and NO3-N with atrazine at 8 μg/ml was slightly higher than that of the control, but was significantly reduced at higher concentrations. Values for glucose utilization efficiency inT.virideincreased with herbicide at 8 and 20 μg/ml, then decreased considerably at other concentrations, but remained higher than the control; a similar pattern was revealed for P and NO3-N utilization. Titratable acidity in the medium increased for both fungi with increased atrazine concentration.

ISSN:0008-4166    

DOI:10.1139/m67-180

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

A chloroform extract of the mycelium ofFusarium oxysporumSchl. em. Sny. et Hans, was analyzed for sterols; three major components were identified as ergosterol, ergosterol peroxide, and cerevisterol. The ratio of ergosterol to ergosterol peroxide formed was variable. Palmitic, stearic, oleic, and linoleic acids were identified by gas–liquid chromatography as the principal fatty acids of this organism.Fusaric acid, a phytotoxin previously obtained by other investigators from a number of forms ofF.oxysporum, was isolated from the culture medium.

ISSN:0008-4166    

DOI:10.1139/m67-181

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Six hundred and sixteen Gram-negative bacterial isolates were obtained from trees and orchards diseased with fire blight. By serological means, 194Erwinia amylovoraisolates were distinguished from 57 nonpigmented isolates of miscellaneous colonial types. One hundred and eighty-nine isolates were distinguished by yellow colony color. In addition, 176 isolates produced a fluorescent pigment. Four other biochemical tests were applied to the isolates.All of theE.amylovoraisolates, 26 'miscellaneous white' isolates, and 94 'yellow' isolates were lysed by one or more of seven phages. Two phages, 1507 and 1508, lysed many isolates from all three groups, and in this way relationships were indicated. Phage sensitivity was not correlated with other characteristics, although phage P19 lysed most of theE.amylovoraisolates and none of the yellow. Phage P17 lysed a majority of the 'yellow' isolates and none of theE.amylovora. Both phages lysed some 'miscellaneous white' isolates.

ISSN:0008-4166    

DOI:10.1139/m67-182

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Forty-two cultures, representing 22 genera of bacteria, were tested for 123 properties. The data obtained were coded and subjected to Adansonian analysis by electronic computer. At 80% or greater similarity levels, six distinct groups were present: group 1, which contained the enterobacteria andAeromonas; group 2 containedPseudomonas,Vibrio cuneatus,Achromobacter, andAcinetobacter; group 3 containedAgrobacterium; group 4, the largest cluster, had two subgroups, 4a, containing the Gram-positive cocci,Nocardia,Mycobacterium, andArthrobacterspp., and 4b, containing the streptomycetes; group 5 containedCytophagaand group 6, containingBacillusspp.,Bacillus pantothenticus, andProtaminobacter alboflavus, did not share a high phenetic similarity with any of the above cultures and the clusters were regarded as isolated and single-item. The results confirmed earlier indications that the evaluation of taxonomic relationships by numerical methods can indicate areas in need of closer examination.

ISSN:0008-4166    

DOI:10.1139/m67-183

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Diffusible external antigens of whole cells ofRhizobium melilotiPDD1322 lost the capacity to precipitate with homologous antibodies in the gel diffusion test, when the cells were disrupted by ultrasonic oscillation. Sonicated cell preparations caused diminution of the homologous precipitin reaction when mixed with suspensions of whole cells. Sonicates contained a new, faster-diffusing antigen component, probably of intracellular origin. The serological inactivity of these sonicates was reversed by boiling. Diffusible antigens of whole cells ofR.melilotiSU388, a strain closely related serologically to PDD1322, behaved similarly, whereas the cross-reacting antigens of strain CC8, of distant serological relationship to PDD 1322, were not affected by sonication. It is suggested that the external antigens and some intracellular compound released by sonication form a heat-labile, relatively nonspecific complex which will not take part in the precipitin reaction. Antibodies to sonicates of PDD1322 reacted strongly with the diffusible external antigens of whole cells of this strain. The same antigens of homologous sonicates reacted very feebly, but the new faster-diffusing component was evident.

ISSN:0008-4166    

DOI:10.1139/m67-184

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

A two-stage multivariate procedure for analysis and condensation of large sets of +/− data has been tested on data derived from application of 75 tests to 59 named cultures ofAerobacter,Aeromonas,Bacillus,Escherichia, andPseudomonas. Seventeen clusters of associated attributes (attribute-complexes) were found by Adansonian R-analysis. As a result of successive separate principal component analyses, 47 principal component vectors were found which cumulatively accounted for 88% of aggregate variance and collectively defined an attribute-complex subspace. Four leading principal component vectors were extracted from attribute-complex space and accounted for 43% of the original variance; cultures were allotted 4-part ordination scores in respect of these vectors and these scores were treated as coordinates of item-points for purposes of cluster analysis. Cultures were separated into appropriate major categories but minor groupings were not entirely satisfactory; deficiences in the data and geometrical distortion during condensation were implicated. Major discriminants were defined in terms of important individual attributes, of combinations of attributes, and of attribute complexes.

ISSN:0008-4166    

DOI:10.1139/m67-185

出版商:NRC Research Press    

年代:1967

数据来源: NRC