摘要:

Acetylene (0.1 atm) prevented rapid increase of CO2evolution in glucose-amended anaerobically incubated sandy loam soil. This effect was explainable in terms of an effect of C2H2on nitrogen-fixing Clostridia.In a N2ase-repressedClostridium pasteurianumculture growing on a medium supplemented with 339 μg NH4-N/ml, C2H2caused 60 to 100% inhibition of cell proliferation and of cell-nitrogen accumulation, and prevented the increase in rate of CO2evolution normally associated with growth. In N2ase-containing cultures the competitive inhibition of nitrogen fixation by C2H2was relieved when C2H2reduction brought thepC2H2to near 0.025 atm. The C2H2inhibition of the NH4-grown culture, however, was not reversed by removal of the C2H2after 11 h of exposure. Ethylene showed no inhibitory effect.Variation of NH4-N concentration and addition, to the medium, of casein hydrolysate and of pyruvate separately and in combination had no marked effect on the inhibition pattern.The effect of C2H2reported here suggests that, until more information is available, the results of long-term C2H2assays of low-activity materials such as soils should be interpreted with some caution.

ISSN:0008-4166    

DOI:10.1139/m71-238

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The cellular fatty acid composition of 33 strains representing 15 species of nonpathogenicNeisseriawas examined by gas–liquid chromatography. Each isolate was characterized by standard biochemical and cultural methods. Media composition influenced both the qualitative and quantitative fatty acid content of some strains examined. However, on the basis of their fatty acid composition, the species formed the same general groups regardless of the media used.N.flavescens,N.canis,N.subflava,N.flava,N.sicca,N.perflava.N.cuniculi,N.mucosa, andN.cinereaformed one fairly homogeneous group with similar fatty acid composition. Palmitic, a monoenoic 16-carbon, a monoenoic 18-carbon, β-hydroxylauric, lauric, and myristic acids were the major fatty acids present and constituted 85–90% of the total fatty acids found.N.lactamicusgrown in trypticase soy broth (TSB) could be included with this general group, but it differed from all other species when grown on plates of Difco GC medium base with 1% defined supplement (GCBDS).N.catarrhalis,N.caviae, andN.ovisformed a second homogeneous group which was characterized by the presence of decanoic acid in addition to the fatty acids found in the other species. The members of this second group were further characterized after growth on GCBDS plates by the presence of large amounts of monoenoic 17-carbon acid.N.denitrificansandN.haemolysanslacked β-hydroxylauric acid, a fatty acid which has been found in relatively large amounts in over 100 isolates of variousNeisseriaspecies examined in this laboratory.

ISSN:0008-4166    

DOI:10.1139/m71-239

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

A comparative study was made of the fatty acids of several gram-positive, -variable, and -negative micrococci. The fatty acids detected inM.diversus,M.denitrificans, andM.cerificans(Acinetobacter cerificans) were similar to those previously reported in gram-negative cocci and bacilli. The major fatty acid was oleic acid and the next most abundant acids were palmitic and palmitoleic.Micrococcus agilis, a gram-positive bacterium, was shown to have a branched-chain methyltetradecanoic acid as the major component (72%). Branched-chain and odd-numbered carbon acids as well as copious amounts of palmitic and palmitoleic acids were found inM.roseus, a gram-variable organism. Correlations were made between fatty acid composition, cell wall structure, and gram reaction ofM.agilis,M.roseus, andM.cerificans. Micrococcus agilisdemonstrated a typical amorphous gram-positive wall,M.roseuswas shown to have a layered wall, andM.cerificanshad a cell wall characteristic of gram-negative bacteria. The relationship of fatty acid composition and ultrastructure to the taxonomic position of the "problematic" micrococci was discussed.

ISSN:0008-4166    

DOI:10.1139/m71-240

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

A hemagglutinogen was isolated from the soluble antigens of a 6BC strain of psittacosis grown in cell culture. The antigen, which was purified by chromatography and electrophoresis, has a molecular weight of 100 000 to 120 000 and a density of 1.235 at 4 °C. The serologic activity of the hemagglutinogen was not affected by acid hydrolysis but was decreased by neuraminidase treatment. It reacted more strongly with homologous than with heterologous antiserum, which might suggest the presence of more than one antigen in the preparation not separable on the basis of molecular weight, density, or electro-phoretic mobility in polyacrylamide gel. A possible alternative explanation would be the presence of a group- and type-specific activity on the same molecule.

ISSN:0008-4166    

DOI:10.1139/m71-241

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Production of sporangia ofPhytophthora cinnamomion agar–mycelial disks in a mineral salts solution was induced by extracts of a soil pseudomonad. Acetone extracts of soil and of mixed populations of microorganisms from soil solution also stimulated the formation of these asexual reproductive structures. Active extracts stimulated sporangium production in aqueous dilutions as high as 10−9. Some extracts of the bacterium were less active at dilutions above or below a certain optimum concentration range. The unidentified, active substance was characterized as a nonvolatile, polar, heat-stable compound that is soluble in water and several organic solvents. Salts of Ca, Mg, K, and Fe in the suspending medium favored a limited production of sporangia in the absence of active substance, and abundant sporangia in its presence. Ca2+was essential for maximum response. The substance was detected by bioassay on paper and thin-layer chromatograms, and it was obtained partially purified.

ISSN:0008-4166    

DOI:10.1139/m71-242

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

PolyI: C (complexed polyinosinic and polycytidylic acids) has been demonstrated to protect mice against infection with lethal doses of a highly virulent mutant of Mengo virus. However, the serum interferon titers it induced were considerably lower and of much shorter duration than the interferon titers induced by infection with the Mengo virus mutant. Evidence has been obtained that the interferon induced by polyI: C is as effective against Mengo virus infection as polyI: C itself. It has also been shown that, unit for unit (measured by the plaque reduction of vesicular stomatitis virus), the polyI: C-induced interferon is much more effective against Mengo virus infection than the Mengo virus-induced interferon itself.

ISSN:0008-4166    

DOI:10.1139/m71-243

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Hyphae ofV.albo-atrumunderwent morphological changes resulting in the death, by autolysis, of about 90% of the hyphae comprising the colony. The remaining hyphae became vacuolate and exhibited an increase in endoplasmic reticulum and mitochondria and extruded melanizing particles through the thickened cell wall to give rise to resting mycelium. These observations are characteristic of the fungus. Resting mycelium resulted from a modification of single, unbranched hyphae and not from repeated budding of single or contiguous hyphae. This confirms thatV.albo-atrumis morphologically distinct from the microsclerotial form of the genus.

ISSN:0008-4166    

DOI:10.1139/m71-244

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Cytoplasms, capsules, cell walls, and extracellular antigens orMycococcuswere prepared and examined by selected chemical and immunological methods. Soluble components were separated and purified by the isoelectrofocusing and polyacrylamide electrophoresis. Chemical analysis revealed that the cell walls were composed of phosphatide–mucopolysaccharides. The cytoplasm consisted mainly of nucleoprotein–polysaccharides, and the capsular material was composed of phosphatide–muconucleo-proteins. The culture filtrate antigen consisted mainly of polysaccharide–proteins. The antigen preparations were found to share at least one major antigenic component. The cytoplasm ofMycococcusrevealed close immunological relationships to seven cytoplasm serogroups of nocardiae, four serogroups of scotochromogenic mycobacteria, and one cytoplasm serogroup ofDermatophilus. In an overall scheme of biological relationships,Mycococcusappears to be situated between the "lower" (fast-growing) mycobacteria and the "higher" (slow-growing) nocardiae.

ISSN:0008-4166    

DOI:10.1139/m71-245

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

A cell-free protein-synthesizing system fromProteus vulgariswas developed and characterized. Initially, a very low activity was found to occur; it was shown to be due to a deficiency in the endogenous transfer ribonucleic acid (tRNA) content of the cell extracts. When tRNA was added to the polyuridylic acid (poly U) directed system, incorporation of14C-phenylalanine into polypeptide readily occurred. This incorporation was dependent on ribosomes and supernatant fraction and the optimum concentrations of the various components of the system were found to be as follows: 120 μg/ml tRNA, 30 mMmagnesium, 0.5 mMspermidine, 60 mMpotassium, 50 mMadenosine triphosphate (ATP), 5 mMguanosine triphosphate (GTP), 0.03 mMcytosine triphosphate (CTP) and uridine triphosphate (UTP), 5 mMphosphoenolpyruvate (PEP), 50 μg/ml poly U, and 30 mM2-mercaptoethanol.

ISSN:0008-4166    

DOI:10.1139/m71-246

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Pseudomonassp. was isolated from sewage effluent by elective culture with nitrilotriacetic acid (NTA) as its sole nitrogen and carbon source for growth. NTA-nitrogen was converted to biomass and ammonium by growing cultures with small quantities of nitrite (< 1 ppm) being produced. Washed cell suspensions degraded all of the NTA-nitrogen to ammonium before total conversion of the NTA-carbon to carbon dioxide and water. Resting cell suspensions grown from NTA oxidized NTA, aminodiacetic acid, and glycine immediately, whereas methylaminodiacetic acid was oxidized only after an adaptive lag period, and sarcosine was not oxidized at all. Oxidation of aminodiacetic acid was always more rapid than NTA. Nitrosamines or other nitroso compounds were not found in culture or resting cell supernatants incubated with NTA.

ISSN:0008-4166    

DOI:10.1139/m71-247

出版商:NRC Research Press    

年代:1971

数据来源: NRC