摘要:

AMicrococcussp., similar toM.flavus, was found to reverse the inhibitory effects of 2,2-dichloropropionic acid (Dalapon) on an unidentifiedAgarbacteriumsp. Neither organism could be shown to degrade the herbicide, as determined by Cl−release or disappearance of the agent from the medium. Bioassay of the filtered micrococcal broth revealed the presence of pantothenic acid. β-Alanine, valine, and alpha-ketoisovalerate could not overcome the herbicide's inhibitory effects on theAgarbacterium, but sodium pamoate produced a slight increase in growth. Calcium pantothenate (0.05 ug/ml) allowed the same amount of growth of theAgarbacteriumin Dalapon medium as did the micrococcal filtrate. The finding suggests that an "associative action" of microorganisms may play an important role in microbial resistance to herbicides.

ISSN:0008-4166    

DOI:10.1139/m69-203

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Cell division in cells ofMycoplasma gallisepticumstrains A5969 and S6 was studied. No differences were found between the two strains.During growth young cells either increase in length, in width, or in both directions. A second bleb may develop at various sites in the cell. Division appears to be related to the position of the bleb, and may be transverse or longitudinal. In addition, a divisional form resembling "budding" occurs, which may also produce equal or unequal daughter cells. As division proceeds, new membranes are formed and the cells appear to separate.Polysomes were found in the logarithmic phase, while in the lag phase only ribosomes were observed. With the growth of the cells polysomes and ribosomes migrate to regions where protein synthesis occurs.

ISSN:0008-4166    

DOI:10.1139/m69-204

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Two toxic components (I and II) ofClostridium botulinumtype A were separated by chromatography on Sephadex G–200. The relationship between these components was investigated. Antisera prepared against either component I or II cross-neutralized both toxins. The neutralizing values of each antiserum were the same when tested at the L+/50 level against components I and II, and unfractionated toxin.Component I was associated with hemagglutinating activity. Toxin and hemagglutinin were separated by chromatography on diethylaminoethyl (DEAE) cellulose. Rechromatography of the toxin on Sephadex G–200 showed a reduction in molecular weight from 450 000 to 140 000. Component II was free of hemagglutinin, but its molecular weight shifted from 190 000 to 140 000 and its Stokes radius from 5.8 mμ to 4.8 mμ upon chromatography on DEAE cellulose.It is concluded that components I and II have similar or identical antigenic sites, and it appears that their toxic moieties are also similar or identical in composition.

ISSN:0008-4166    

DOI:10.1139/m69-205

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

The basis for determination of nodulating specificity inRhizobium–clover associations was investigated. Thirteen strains of rhizobia from eight different cross-inoculation groups were used to inoculate aseptically grown strawberry clover seedlings in slide culture. Microscopic observation revealed that each strain produced characteristic root hair deformation but infection threads and nodules were observed only in the homologous combination. It is concluded that, in rhizobia–clover combinations which nodulate via infection threads, specificity is determined at or before infection thread initiation. Observations of other workers that rhizobia produce a strain-specific substance affecting growth and morphology of legume root hairs were confirmed by results of this study.

ISSN:0008-4166    

DOI:10.1139/m69-206

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Growth of white-rot fungi was inhibited by dihydroquercetin (3,5,7,3′,4′-pentahydroxy flavanone) in a liquid medium, while brown-rot fungi were generally unaffected by the presence of this compound at concentrations up to 0.16%. Dihydroquercetin was recovered from the cultures of brown-rot fungi, but degraded by white-rot fungi, suggesting that the degradation products might be more toxic than dihydroquercetin itself. Among the stain and mold fungi,Chaetomium globosumreacted similarly to this flavonone as white-rot fungi, while the growth ofTrichoderma virgatumandAspergillus sydowiwere similar to brown-rot fungi.Cephaloascus fragransandPenicilliumsp. tolerated dihydroquercetin in the medium, but were also able to degrade it.

ISSN:0008-4166    

DOI:10.1139/m69-207

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Particulate antigens were prepared in the form of mycelial fragments and spores, or as cell walls from 24 strains ofDermatophilusand from 22 strains of other actinomycetes. The antigen preparations were tested with either non-labeled or fluorescein isothiocyanate labeled antisera or antiserum globulins. Seven particulate antigen groups ofDermatophiluswere distinguished. The particulate antigen preparations ofDermatophilusrevealed considerable similarity to the serological reaction patterns of endoplasms and exoantigens. No serological relationship was discovered between the particulate antigens ofDermatophilusand of other actinomycetes.

ISSN:0008-4166    

DOI:10.1139/m69-208

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Several mutants with elevated maximal growth temperature (MGT) were developed from an obligate psychrophile,Micrococcus cryophilusATCC 15174, by ultraviolet irradiation. Two of the mutants, T8 and M19, have the most similar characteristics to those of their parent. The mutants lost the ability to grow well at 0 °C and showed changes in metabolic pathways while acquiring the ability to grow at elevated temperatures. Heat resistance and deoxyribonucleic acid thermal denaturation temperature were shown to be unrelated to maximum growth temperature. The significance of the mutants is discussed.

ISSN:0008-4166    

DOI:10.1139/m69-209

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

The temperature characteristic for growth (μ) has been determined for an obligate psychrophile,Micrococcus cryophilusATCC 15174, and its mesophilic mutants. The use of μ. for characterizing psychrophiles and mesophiles is discussed.Solute-transporting and energy-yielding systems were shown to be unrelated to maximum growth temperature.Endogenous respiration and the temperature characteristic of substrate oxidation were both found to be unsuitable as a means of characterizing mesophiles and psychrophiles. The temperature coefficient of substrate oxidation (Q10), with reference temperatures set at 10 and 30 °C is suggested for this purpose, mesophiles having a higher value than psychrophiles.

ISSN:0008-4166    

DOI:10.1139/m69-210

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Growth ofHalobacterium cutirubrum,H.salinarium, andH.halobiumwas followed by viable counts and optical density measurements. The last species, which grows most vigorously, was most intensively studied.The increase of optical densities and the increase in viable counts corresponded through the exponential growth phase. Dead cells did not lyse, and viable counts were needed to show that after the stationary phase was reached some cultures died off rapidly. Others remained stable for several days. Potassium can limit growth in synthetic media; in all media abundant growth could be obtained only when about 1 mg/ml K+was present. Growth was stimulated by glycerol, certain carbohydrates, related metabolites, and vitamins. The most effective growth-promoting vitamins tested were thiamine, folic acid, biotin, and vitamin B12. Metabolites that stimulated growth were galactose, glucose, sodium lactate, and glutamine. One-tenth percent glycerol, sodium succinate, and sodium pyruvate were stimulatory, although 2.0% concentrations were inhibitory. Though carbohydrates may stimulate growth, the medium does not become acid; this may explain why standard bacteriological tests indicate that many extreme halophiles do not "utilize" carbohydrates.H.halobiumproduced considerable acid only when grown in the presence of 2% glycerol.

ISSN:0008-4166    

DOI:10.1139/m69-211

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Gel filtration has been investigated as a method for purifying adenovirus antigens in tissue culture fluid. It was found that by molecular sieving through the agarose Sepharose 4B, most of the infectivity, hemagglutinins, and nonspecific complement-fixing (CF) activity could be separated from a second fraction which contained some hemagglutinin but only a low titer of viable virus and from a third fraction which contained the group-specific complement-fixing antigen but was relatively free of hemagglutinin, viable virus, and nonspecific reactants.For the routine production of a noninfective, purified group-specific diagnostic antigen for adenovirus, the bulk infected fluid is inactivated by heating at 56 °C for 3 hours at pH 5.5 or by gamma irradiation with 2.5 megarads, concentrated about 20-fold by pervaporation or by pressure filtration, purified by gel filtration using Sepharose 4B, concentrated to desired potency, and then lyophilized for stable storage.

ISSN:0008-4166    

DOI:10.1139/m69-212

出版商:NRC Research Press    

年代:1969

数据来源: NRC