摘要:

Micrococcus variansssp.halophilusATCC 21971 showed abundant growth in complex media containing 1 MNaCl, NaBr, NaI, NaNO3, Na2SO4, KCl, KBr, KI, or KNO3, and 2 MRbCl or RbBr at 30 °C.Spontaneous mutants were isolated which were able to grow in a medium of 1.5 MLiCl (strain Li-5) or 2.5 MCsCl (strain Cs-7-Cs). Determination of cell-associated cation concentration at the exponential phase of growth showed that the cells contained monovalent cations of almost equivalent concentration as that in the medium: 0.570 mLi++ 0.951 mNa+in 1.5 MLiCl grown cells; 2.88 mNa+in 3.0 MNaCl grown cells; 2.66 mK+in 3.0 MKCl grown cells; 1.57 mRb+in 2.0 MRbCl grown cells; 1.44 mCs+in 1.5 MCsCl grown cells.

ISSN:0008-4166    

DOI:10.1139/m82-020

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

Nodulation ofPisum sativumcv. Afghanistan byRhizobium leguminosarumstrain Tom can be blocked byR.leguminosarumstrain PF2(isolated fromP.sativumcv. Rondo) which does not form nodules of Afghanistan peas. We tested PF2for its ability to produce bacteriocins and other compounds inhibitory to the growth of Tom. Neither strain was antagonistic toward the other. Similarly, there was no evidence for the production of inhibitors as the rhizobia grew in the plant rhizosphere. Apart from an already noted (Broughtonet al. 1980. Can. J. Microbiol. 26: 562–565) ability of PF2to accumulate on the root surfaces two to three times faster than Tom, we could not find a reason to explain the complete blocking of nodulation. In other experiments using PF2(and Tom) killed by exposure to massive doses of gamma irradiation, dead cells still bound to the roots but they were incapable of blocking nodulation by living Tom. Finally, when both rhizobia were used to inoculateP.sativumcv. Rondo (they both form nodules on this plant), roughly one third of the nodules contained Tom, one third contained PF2, and one third contained both strains (i.e.,there was no evidence for competition). We conclude, therefore, that competition in this system is dependent upon live bacteria and requires cooperation from the plant.

ISSN:0008-4166    

DOI:10.1139/m82-021

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

The role of the outer membrane (OM) was investigated in relation to the high level of intrinsic antibiotic resistance ofPseudomonas aeruginosaATCC 9027. OM penetration barriers were measured by comparing turbidimetric growth curves of EDTA-treated and normal cells exposed to carbenicillin, moxalactam (LY 127935), gentamicin, tobramycin, rifampin, novobiocin, and vancomycin. OM barriers were also measured for carbenicillin and moxalactam inP.aeruginosastrain K 799/61, a hypersusceptible mutant presumed to have lost its penetration barrier in the cell envelope. Most antibiotics penetrated the OM efficiently and there was little difference between the two strains. The evidence therefore suggests that intrinsic resistance ofP.aeruginosa, especially to the beta-lactam antibiotics, is not mainly due to the OM. A penetration barrier situated deeper within the cell envelope is hypothesized, the size of which in relation to any antibiotic may be estimated by comparing the IC50values of EDTA-treated cells of the two strains.

ISSN:0008-4166    

DOI:10.1139/m82-022

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

Klebsiella pneumoniaewas found to effect the reductive dechlorination of methoxychlor (2,2-bis(p-mefhoxyphenyl)-1,1,1-trichloroethane) and its dihydroxy derivative (2,2-bis(p-hydroxyphenyl)-1,1,1-trichloroethane) to dichloro derivatives 2,2-bis(p-methoxyphenyl)-1,1-dichloroethane and 2,2-bis(p-hydroxyphenyl)-1,1-dichloroethane, respectively. Dehydrohalogenation to the corresponding diaryl dichloroethylenes, which themselves were not further degraded by this bacterium, was not observed. Cleavage of the methoxy groups to form the hydroxy compounds did not take place.

ISSN:0008-4166    

DOI:10.1139/m82-023

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

Fifteen specific bacteriophages, each active on particular strains ofRhizobium meliloti, have been selected from those isolated by enrichment of local soils. Variables affecting phage–host interaction have been examined and standardized. The differential susceptibility of individualR.melilotistrains to each phage produces a distinctive pattern of response which allows the segregation of each strain into one of the 80 different groups identified to date. Discrimination between strains with this typing system is reproducible with no change in phage type following extended subculture or plant infection and reisolation of strains from root nodules of alfalfa. The large number of different strains recognized by the system should make it very useful in experimentally controlled tests of selected strains in the nodulation of alfalfa plants.

ISSN:0008-4166    

DOI:10.1139/m82-024

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

A spontaneous mutant ofStreptococcus salivariusATCC 25975 was isolated by inoculating an agar medium containing 11 mMlactose and 0.5 mM2-deoxyglucose. This mutant grew poorly on 5 mMglucose but almost as well as the parental strain on 110 mMglucose. Uptake of 2-deoxyglucose was abolished by the mutation, and phosphoenolpyruvate:glucose phosphotransferase activity could not be detected with toluenized cells under normal conditions when the glucose concentration was below 5 mM. Data from growth experiments, glycolysis, and uptake studies indicated the presence of a second phosphoenolpyruvate: glucose phosphotransferase system that could catalyze the phosphorylation of α-methyl glucoside. The activity of this system was detected by a spectrophotometric assay coupled with lactate dehydrogenase and by a radioactive isotope method using methyl α-D-[U-14C]glucoside. The phosphorylation was phosphoenolpyruvate dependent. The apparentKmof the system for glucose and α-methyl glucoside was approximately 20 mM. Studies with energy poisons ruled out the possibility of an active transport system, and accumulation of α-methyl glucoside argued against facilitated diffusion. It was concluded that the other glucose transport system which allowed growth of the mutant strain ofS.salivariuswas a second phosphoenolpyruvate:glucose phosphotransferase system.

ISSN:0008-4166    

DOI:10.1139/m82-025

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

Wild and domestic animals of New Brunswick were tested serologically for antibodies to the California group (CAL) of arboviruses. Deer (Odocoileus virginianus) blood collected during 1976 showed 6 of 129 (4.7%) sera with neutralizing antibodies to the snowshoe hare strain (SSH) of CAL. Neutralization tests on moose (Alces alces americanaClinton) sera collected during 1979 indicated 94 of 127 (74%) with antibodies to SSH, 4 of 127 (3.2%) with antibodies to the Jamestown Canyon strain (JC) of CAL, and 17 of 127 (13.4%) with equal antibody titers to SSH and JC. Hemagglutination inhibition tests on horse blood collected during 1977 showed 54 of 204 (26.5 %) with antibodies to SSH; of these, 36 also had neutralizing antibodies to SSH. This study is the first indication of CAL activity in New Brunswick and supports evidence of JC activity in northeastern North America.

ISSN:0008-4166    

DOI:10.1139/m82-026

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

Xanthomonas campestrispv.undulosadid not inhibit growth or spore germination ofSeptoria nodorumon wheat leaf extract agar, whereasPseudomonas cepaciaproduced a zone of complete inhibition of spore germination up to 17.5 mm and reduced germination up to 5 cm from the bacterial front. Culture filtrates of the two bacteria grown in 'Blueboy' or 'Arthur' wheat leaf extract broth were incorporated into fresh wheat leaf extract broth. These filtrates caused a reduction in growth (dry weight) ofS.nodorumcompared with growth in unamended extract. Fungal mass was considerably lower inP.cepaciafiltrate of 'Arthur' wheat than in theX.campestrispv.undulosafiltrate or the control. The extent of reduction byP.cepaciafiltrate suggests an antibiotic effect. In phosphate buffer,X.campestrispv.undulosareduced spore germination and germ tube length ofS.nodorum, whileP.cepaciainhibited germination and germ tube growth completely.In vivo,X.campestrispv.undulosahad no effect on spore germination but did reduce germ tube length whereasP.cepaciainhibited both parameters.

ISSN:0008-4166    

DOI:10.1139/m82-027

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

The ultrastructure of yeast, intermediate transitional forms, and mycelia ofBlastomyces dermatitidiscultured in brain heart infusion (BHI) was compared with that of like forms grown in leucine–glucose (LG) medium.Blastomyces dermatitidisyeasts were also grown in yeast extract – peptone (YP) medium and in glucose – yeast extract – peptone (GYP) medium, and their ultrastructures were compared with BHI-grown yeasts. Yeast, intermediate, and mycelial cells cultured in LG had more granular cytoplasm and better defined membranes than analogous BHI-grown cells. Yeasts grown in LG contained more glycogen and fewer lipid bodies and had no visible intracytoplasmic membrane systems. Some yeasts from LG cultures had bizarre shapes and structure. Intermediate and mycelial forms from LG cultures contained more glycogen and lipid bodies than analogous cells from BHI. Yeasts grown in YP had a more highly defined internal structure than BHI-grown yeasts. Some cells were doubly budded, and some were elongated. Similar elongated yeasts were found growing in GYP. Yeasts grown in GYP lacked a well-defined internal structure and had less glycogen than BHI-grown yeasts. They had no visible lipid bodies, but large vacuoles were present. Intrayeast hyphae were observed only in BHI-grown intermediate cells.

ISSN:0008-4166    

DOI:10.1139/m82-028

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

Normal and trypsinized human erythrocyte membranes were used as a model in the study of host cell receptors forNeisseria gonorrhoeae. Receptor sites were identified by adherence inhibition assays of fractions of membranes eluted from polyacrylamide gel electrophoresis columns. Results indicated that inhibition of gonococcus T1and T4adherence was associated with erythrocyte protein bands 3 and 4 and glycophorin A, the major sialoglycoprotein. Further investigation revealed that band 3 preparations isolated by affinity chromatography on concanavalin A – Sepharose 4B columns continued to inhibit T1adherence to erythrocytes but did not inhibit adherence of T4organisms. It is suggested that protein band 3 is the receptor on erythrocytes for T1gonococci and that glycophorin A may be the receptor for T4cells.

ISSN:0008-4166    

DOI:10.1139/m82-029

出版商:NRC Research Press    

年代:1982

数据来源: NRC