摘要:

Spore counts and heat resistance ofBacillus stearothermophilusand thermophilic actinomycetes were influenced by types of crops and were correlated positively with Mn, Ca, P, pHw, and pHsof soil from Sanborn Field, Columbia, Mo. In greenhouse soil, positive correlations were found between thermophilic aerobes and Mg, Ca, K, and cation-exchange capacity. Also, in the greenhouse soil, negative correlations occurred between counts for thermophilic aerobes and pHwand pHs. Spores in soils in Sanborn Field were more heat- resistant than spores in greenhouse soil. The number of germinating spores in dry soil stored at 25Cand 1.1C increased after 1 month and remained at the same relative number for 9 months at which time counts declined at both temperatures.

ISSN:0008-4166    

DOI:10.1139/m74-253

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

In a young culture, photosynthetic-oxygen evolution byGloeocapsais at a low level while nitrogenase activity is at its greatest. When the culture ages, there is a rapid increase in photosynthetic pigments and oxygen evolution, and nitrogenase activity decreases. The temporal separation of nitrogen fixation and photosynthesis may serve to protect nitrogenase from oxygen denaturation.

ISSN:0008-4166    

DOI:10.1139/m74-254

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Marine sediments inoculated into cooked meat medium were enriched for 5 months at 0–5 °C. Organisms isolated and purified were tested for growth at low temperatures, and those growing only anaerobically at 5 °C and below were retained for further study. The growth–temperature range was determined by growing 18 isolates on a temperature-gradient incubator over a temperature range of 0 to 34 °C. On the bases of minimum, optimum, and maximum growth temperatures, the 18 isolates were separated into obligate and facultative psychrophilic and psychrotrophic clostridia. The DNA was extracted from cells grown at 12 °C and the percentage of G + C for all the isolates fell within the range characteristic ofClostridiumspecies. The volatile alcohols and acids produced on a glucose medium were detected by gas chromatography. Ten of the isolates produced no alcohols and only acetic and butyric acids. One isolate produced butanol and acetic and butyric acids. The remaining seven isolates produced one or two alcohols, ethanol and butanol, and up to six acids. The 18 isolates fell into distinct groups with a close relationship between growth–temperature range and volatile alcoholic and acidic products. Biochemical tests showed that the isolates resembledClostridiumspecies described in the literature; however, they were not like any known species and were not named.

ISSN:0008-4166    

DOI:10.1139/m74-255

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The parameters for iron oxidation by isolated cell envelopes ofThiobacillus ferrooxidanswere studied using a Clark oxygen electrode. Envelopes were obtained by breaking thoroughly washed cells in a French pressure cell and by sedimenting the envelope fraction by ultracentrifugation. The envelopes were partially purified by sucrose density-gradient centrifugation. A broad band was separated at a specific gravity of about 1.21 g/cm3which coincided with the major protein peak and iron oxidation activity. Electron micrographs confirmed that the active preparations were cell envelopes consisting of the cytoplasmic membrane, peptidoglycan layer, and the outer lipopolysaccharide–lipoprotein double track layer of gram-negative bacteria. Numerous membrane vesicles were also present. Lysozyme had little effect upon iron oxidation activity whereas treating cell envelopes with Triton X-100 destroyed activity. Iron oxidation by cell envelopes was completely inhibited by heating in boiling water or by adding 1% trichloroacetic acid to the reaction cuvette.Kinetic analysis of iron oxidation by envelopes in β-alanine-SO42−buffer (pH 3.5) showed an apparentKmof 5.4 × 10−3 M. The apparentKmwith whole cells was 2.1 × 10−3 M. The pH optimum for iron oxidation by cell envelopes was between pH 3.0 and 3.5 while for whole cells the optimum was pH 2.0–2.5.Spectrophotometric studies identified the membrane-bound cytochromes as cytochromescanda; cytochromebwas also present but its function is unknown at this time.

ISSN:0008-4166    

DOI:10.1139/m74-256

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

An identification system was developed for enterobacteria isolated frequently from hospital patients, involving a set of biochemical reactions on agar media. The media were inoculated by a replication apparatus also used for setting up antibiotic sensitivity tests. Cultures in a control series showed a close correlation between reactions on the agar media and classical tests in a fluid medium. Of a series of 2668 laboratory isolates of enterobacteria, 2292 were identified outright by the selected reactions, 160 required one further test, and 216 could be identified only after repeating the reactions or the performance of additional tests. The identification has the advantages of speed, economy, and simplicity and is recommended for hospital laboratories handling large numbers of enterobacterial cultures.

ISSN:0008-4166    

DOI:10.1139/m74-257

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The paper describes the materials and procedures presently used at the American Type Culture Collection (ATCC) for the long-term preservation of living fungi pathogenic for man and animals by freeze-drying and by freezing and subsequent storage in liquid nitrogen. Longevity storage data for the strains available for distribution is presented.

ISSN:0008-4166    

DOI:10.1139/m74-258

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Samples of two streams, a primary oxidation product and a main recycle stream, were obtained from a large industrial plant oxidizing butane. These are not wastes, but streams within the production process, containing mixtures of oxidation products of butane. Their suitability as substrates for yeast growth was studied. Generation times and cell yields were determined for 11 different yeasts. The recycle stream gave unexpectedly low cell yields. Growth rates and yields were accordingly determined for 17 pure compounds representing the principal components of the two streams: alcohols, acids, esters, ketones, and an aldehyde, all of five carbon atoms or less. The 11 yeasts showed great variation in their ability to use these components. Yields of yeast based on the carbon content of the two samples were as expected from the individual components, but the recycle stream sample, which was rich in unutilizable ketones, was a poor substrate. The ketones may also have slowed the growth of the yeasts somewhat.

ISSN:0008-4166    

DOI:10.1139/m74-259

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Previous studies reported that nontumorigenic 6C3HED tissue-culture cells induced strong tumor-specific immunoprotection against 6C3HED tumors. However, in the in vitro test, sera from C3H mice immunized with nontumorigenic 6C3HED tissue-culture cells failed to lyse 6C3HED ascites tumor cells when fresh guinea pig serum was incorporated as the complement source. A number of serum samples from different animal species were assayed as a complement source. With the exception of fresh rabbit serum, all other sera were either by themselves toxic to 6C3HED ascites tumor cells, or did not function as a complement source. The rabbit serum, by itself, was not toxic to 6C3HED tumor cells, but when incorporated with the isogeneic mouse-immune serum, killed more than 95% tumor cells. The facilitating activity exhibited by rabbit serum was characterized as classical complement and was not due to the presence of heterophile antibodies in the rabbit serum. By using this immunolytic testing system, the sera from mice bearing 6C3HED, S-180, TA-3, and Ehrlich solid tumors for an extensive time were found toxic to homologous ascites tumor cells. The cross-reactivity of the sera from tumor-bearing animals suggests that these four murine tumors, 6C3HED, S-180, TA-3, and Ehrlich, share some common tumor-specific antigen(s).

ISSN:0008-4166    

DOI:10.1139/m74-260

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The hypothesis that chlorpromazine inhibition of bacterial endospore germination acts at the level of hexose monophosphate shunt (HMP) dehydrogenases was tested and substantiated forBacillus cereusT andBacillus megaterium. However, this cannot be an exclusive mechanism of action in bacterial systems because inhibitory effects on growth and respiration are caused by the drug even when these HMP enzymes are not present in the organisms.

ISSN:0008-4166    

DOI:10.1139/m74-261

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Mutation sites in five Aro−strains ofStreptomyces coelicolorA3(2) were mapped. None of the mutants use quinate or shikimate. Results from mapping, complementation, and growth response to aromatic amino acids and vitamins indicate that at least three different genes are affected in these five mutants.

ISSN:0008-4166    

DOI:10.1139/m74-262

出版商:NRC Research Press    

年代:1974

数据来源: NRC