摘要:

A soluble NAD+-dependent β-hydroxybutyrate (βHB) dehydrogenase was shown to appear 3 to 4 h after the onset of sporulation ofBacillus cereusT. The enzyme was stable in Tris-chloride buffer when frozen, but required 0.05 to 0.1 M of MgCl2or other divalent cation such as Mn2+, Ba2+, or Ca2+for stability at 4C. In the presence of phosphate buffer or EDTA, the enzyme lost all activity within 2 min. βHB dehydrogenase was partially purified and shown to have a molecular weight of about 93 000, pH optimum of 8.0 in 0.1 M Tris-chloride buffer, Michaelis constants,Km, of 2.3 × 10−3 M for β-hydroxybutyrate and 9.5 × 10−4 M for NAD+, and was inhibited 40% by 1 × 10−3 Mp-hydroxymercuribenzoate. The enzyme fromB.cereusT was compared in these respects with βHB dehydrogenases isolated from several non-sporeforming bacteria.

ISSN:0008-4166    

DOI:10.1139/m73-110

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Forty erythromycin-resistant mutants ofBacillus subtilisstrain 168 were isolated as spontaneous mutants or after induction with 2-aminopurine. They showed different levels of resistance and six of these mutants were studied genetically using transformation reactions. Recombination of some pairs of mutations has a synergistic effect on resistance. All six mutants are clustered on theB.subtilischromosome between the genesstrconferring streptomycin resistance andpurB determining purine biosynthesis. Some mutations overlap at the same site. The genetic order of theseerymutations with respect to one another and a streptomycin-resistant mutationstrhas been determined.

ISSN:0008-4166    

DOI:10.1139/m73-111

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

When samples of fresh dung from pigs, horses, sheep, or cattle were enriched to encourage the growth ofCaryophanon latum, the organism was found to be specifically associated with cattle dung. Several sheep dung samples were found to be positive forC.latum, but all were taken from a pasture where sheep and cattle were grazed together. All samples taken from sheep not pastured with cattle were negative. Autoclaved samples of cattle, horse, and sheep dung all supported growth and natural morphology ofC.latumwhen inoculated with pure or mixed cultures of this organism. A large proportion of autoclaved cattle dung samples left open to the air of cattle barns or occupied cattle pastures showed the presence ofC.latumafter 1–4 days exposure. Control samples exposed to air in areas far removed from cattle were uniformly negative. Aseptically collected "free catch" samples from cattle were mainly negative, as were samples collected from the fistulated rumen. Enrichment of various other sources was undertaken. Our total findings support the hypothesis thatC.latumis a natural, specific, and temporary resident of cattle dung and is dispersed to new droppings by contaminated air and also probably by flying insects or cattle movement.

ISSN:0008-4166    

DOI:10.1139/m73-112

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Eight morphological variants, the product of colonial dissociation, were isolated from cultures of the marine pseudomonad B-16. Features which distinguished the variants were smooth versus rough colony type, the presence or absence of color, and differences in colony diameter. The variants differed in their capacity to form stable protoplasts and to grow at suboptimal Na+concentrations in defined medium. All, however, required Na+for growth. The ability of the organism to accumulate α-aminoisobutyric acid (AIB) and the requirement for Na+for this process was not affected by dissociation.

ISSN:0008-4166    

DOI:10.1139/m73-113

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Thirteen species ofNeisseriawere examined for the presence of extracellular carbohydrate antigens. Of three media tested for optimum growth of the bacteria, yield of antigens, and ease of isolation of antigens, dialyzed tryptic soy broth was the best. Seven species,N.catarrhalis,N.cinerea,N.flava,N.flavescens,N.lactamicus,N.subflava, andN.winogradski, yielded extracellular antigens that were extractable into phenol and hence were probably proteinaceous. The remaining six species,N.canis,N.caviae,N.cuniculi,N.cuniculisubsp.gigantea,N.denitrificans, andN.sicca, yielded carbohydrate antigens that were purified by a sequence of phenol extraction, chromatography, enzymic digestion, and membrane filtration. These antigens were polymers of 2-acetamido-2-deoxy-D-glucose and 2-acetamido-2-deoxy-D-galactose, the latter being the only constituent of the antigens fromN.caviaeandN.sicca. Cross-reactivities of the carbohydrate antigens in the homologous antisera showed that there were close relations between the antigens fromN.canisandN.cuniculisubsp.giganteaand also between those fromN.caviaeandN.sicca.

ISSN:0008-4166    

DOI:10.1139/m73-114

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

A method was developed for the elimination of viableMycoplasmain reference seed virus stocks. It was found that various species ofMycoplasma(such asM.pneumoniae,M.arthritidis,M.hominis,M.salivarium,M.oraletypes I and II,M.meleagridis, and several unidentified species isolated from tissue cultures) were inactivated more rapidly by gamma radiation than all viruses tested. By the use of selected radiation doses, high concentrations ofMycoplasmaspecies could be inactivated in virus suspensions of polioviruses types I and III, coxsackie viruses types A-7, A-9, B-3, and B-6, echoviruses types 1, 9, 12, and 20, herpes simplex, rubella, measles, and adenovirus type 7a, without inactivating all viable virus. After irradiation, the remaining viable virus could be propagated as well as the original strain and showed no change in reactivity with homologous or heterologous antisera. After storage for 2 months at −70 °C, the irradiated virus showed no decrease either in viability or in specific reactivity. By this method, reference seed virus stocks could be prepared free of viableMycoplasmaspecies, without dependence on tissue cultures free ofMycoplasma.

ISSN:0008-4166    

DOI:10.1139/m73-115

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The effect of carbon dioxide on propionate formation during lactate and pyruvate metabolism by intact cells and cell-free preparations ofVeillonella parvulaM4was examined. While the overall rate of lactate-U-14C degradation by intact cells was not altered, concentrations of unlabeled CO2(to 50%) stimulated the evolution of14CO2, and increased the absolute quantity of the propionate formed, while decreasing its specific activity. Acetate production from the labeled lactate, however, was not affected. Furthermore, propionate formation was not dependent on the presence of CO2in the gas phase. The principle product of pyruvate-3-14C metabolism by extracts of the organism was acetate, although minor amounts of labeled propionate were also formed. Small quantities of oxaloacetate were detected during this metabolism by direct enzymatic assay and by separation of its hydrazone by thin-layer chromatography. Dialyzed crude extracts of the organism, treated with protamine sulfate and charcoal, were shown to catalyze the formation of oxaloacetate from pyruvate and CO2in the presence of ATP when assayed both enzymatically with malic dehydrogenase and NADH, and with pyruvate-3-14C. This CO2-fixing activity could be attributed to pyruvate carboxylase, since the activity was Mg2+-dependent, was inhibited by avidin and aspartate, and was stimulated by biotin and CoA. Furthermore, the same extract preparation was capable of converting pyruvate-3-14C and CO2to malate in the presence of NADH and NADPH indicating the presence of malic enzyme in the organism; this activity was confirmed by spectrophotometric means. As is the case withV.alcalescens, dialyzed extracts ofV.parvulaM4catalyzed the exchange reaction between the carboxyl group of pyruvate and CO2; this exchange activity was stimulated by ATP.

ISSN:0008-4166    

DOI:10.1139/m73-116

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Zearalenone or F-2 [2,4-dihydroxy-6-(10-hydroxy-6-oxo-trans-1-undecenyl)-benzoic acid lactone] is an estrogenic mycotoxin synthesized byFusarium roseum(Link emend.) Sny. & Hans. 'Graminearum.' In addition to its estrogenic activity in animals, it acts as a sex-regulating hormone inF.roseum, and this is the subject of this paper. When amounts of F-2 ranging from 0.1 ng to 10.0 ng were applied to a 1.0-cm diameter disk of Coons' synthetic medium in agar, perithecial formation was enhanced by as much as 100%. Amounts in excess of 10.0 μg inhibited perithecial formation. F-2 has a periodicity of action relative to both enhancement and inhibition of perithecial formation. The ability of F-2 to enhance was greatest up to 4 days of culture age when amounts optimum (0.1 ng and 1.0 ng) for enhancement were used. Optimum inhibition of perithecial formation with inhibitory amounts (10.0 μg and 100.0 μg) occurred when the culture was from 3 to 4 days old. Dichlorvos (2,2-dichlorovinyl dimethyl phosphate), also called VAPONA, inhibited F-2 biosynthesis as well as production of perithecia. Moreover, when F-2 was applied simultaneously with dichlorvos, the inhibition caused by dichlorvos was reduced. A limited study on structure activity relationships was done with the conclusion that the hydroxyl or ketone in the 6′ position of the undecenyl ring is necessary for activity. Further, unsaturation at the 1′,2′ position on the undecenyl ring of F-2 is associated with inhibitory activity at the higher concentrations.

ISSN:0008-4166    

DOI:10.1139/m73-117

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Ninety strains ofClostridium perfringenswere tested with 8 to 10 different antibiotics by the Kirby-Bauer disc method for determining bacterial sensitivity. The results of these tests were compared with previously established bacteriocin sensitivities of these strains. Twenty-three of the above strains were converted to L-forms by growth in soft agar overlays on plates containing a bacteriocin ofC.perfringensand these were tested with eight antibiotics. A marked resistance to penicillin, ampicillin, and methicillin was apparent in the L-form growth as compared to the degree of sensitivity obtained with the normal growth ofC.perfringens.

ISSN:0008-4166    

DOI:10.1139/m73-118

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Soluble antigens were obtained from the liver of myelocytic and congenital human leukemia cases by hyaluronidase treatment of tissues, extraction with 1 M KCl, and purification by isoelectrofocusing and prolonged gel electrophoresis. The extracts and one isoelectrofocusing fraction obtained from organs of myeloid leukemia, but not those from lymphoid leukemia, reacted with an antiserum produced against the pI 4.85 isoelectrofocusing fraction. A single antigen, which was purified additionally by a prolonged gel electrophoresis, and migrated slightly towards the cathode, was found to react with the rabbit antisera produced against leukemic fractions, absorbed with normal tissues. This antigen was identified as a galactopolypeptide.

ISSN:0008-4166    

DOI:10.1139/m73-119

出版商:NRC Research Press    

年代:1973

数据来源: NRC