摘要:

Chlamydia psittaci(6BC) was grown in yolk sac explants and in L cells and fixed by perfusionin situto provide undamaged material for comparison with gram-negative bacteria. Reticulate, intermediate, and elementary bodies were all seen to lack a well-defined periplasmic space; intermediate and elementary bodies showed condensations of the nucleoid which differ from common bacterial configurations; and the cytoplasm of highly condensed elementary bodies was much more electron dense than that of the gram-negative bacteria, while retaining its basically particulate nature.These important morphological distinctions are interpreted as reflections of a significantly different cellular level of organization in these two groups of organisms. No important morphological differences were noted in comparisons of the chlamydial particles grown in the two different host systems.

ISSN:0008-4166    

DOI:10.1139/m75-215

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

A procedure is described for the purification of mixed populations of the three different morphological forms ofChlamydia psittaci(6BC) from infected yolk sac membranes. Elementary bodies and small intermediate bodies are not perceptibly damaged during purification which involves homogenization of the host cells, differential centrifugation, sedimentation through 20% sucrose, and treatment with trypsin. The observation that elementary bodies undergo plasmolysis in 20% sucrose is interpreted as indicating that the cytoplasmic membrane of these particles is intact at that stage in the purification. Reticulate bodies and large intermediate bodies are damaged, to a degree, by the homogenization step. This damage takes the form of discontinuities of the outer envelope membrane, and results in the loss of the regular coccobacillary shape of these particles and in an increase in their size. Treatment with a combination of RNase and DNase was found to cause profound damage to all three morphological forms of the chlamydiae.

ISSN:0008-4166    

DOI:10.1139/m75-216

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Nonlinear survivor curves were obtained when spores ofBacillus cereuswere heated in physiological saline solution. Curvilinear survivor curves did not appear to be caused by experimental artifacts but by the heterogeneity of spore population with regard to heat resistance.

ISSN:0008-4166    

DOI:10.1139/m75-217

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Axenic, washed conidia ofFusarium solanif. sp.phaseoli,Aspergillus flavus, andVerticillium albo-atrumwere placed on washed Difco purified agar discs along with an inorganic salt solution containing various levels of carbon and nitrogen substrates. These discs were exposed to volatiles from six soils (pH 5.1–8.6).Fusarium solanimacroconidial germination was inhibited mostly by volatiles from soils of pH 5.1, 6.1, 7.0, and 7.5, but high levels of glucose and NH4Cl reversed this inhibition, raising germination to that of no-soil, no-carbon or nitrogen controls. Conidial germination ofA.flavuswas inhibited mainly by volatiles from high pH (7.0, 7.8, and 8.6) soils, and increased levels of glucose plus an amino acid mixture nullified this inhibition. Volatiles from soils of pH 5.1, 6.1, and 7.5 stimulatedA.flavusconidial germination. Assays after the removal of CO2from the air above soil of pH 5.1 demonstrated that volatiles inhibitory toA.flavuswere produced by this soil. Assays indicated that a KOH-soluble compound was a fungistatic soil volatile toF.solanimacroconidial germination. The nullification by carbon and nitrogen substrates ofF.solaniandA.flavusinhibition caused by soil volatiles parallels that for soil fungistasis. Conidial germination ofV.albo-atrumwas markedly stimulated by volatiles in all soils tested, and was not affected by removal of CO2. Inhibitory soil volatiles may increase the nutritional requirements for spore germination of certain fungi.

ISSN:0008-4166    

DOI:10.1139/m75-218

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Ap-nitrophenyl α-galactoside hydrolase is partially released when whole cells ofPseudomonas atlanticaare converted to spheroplasts. Thep-nitrophenyl α-glactoside hydrolase is completely inactivated by treatment of whole cells with diazonaphthalene – disulfonic acid (NDS), a reagent which does not penetrate the cytoplasmic membrane. Under the conditions used no inactivation of lactic acid dehydrogenase was observed. A specific staining procedure for this enzyme for use in electron microscopy was developed. The results with this technique in conjunction with the results of spheroplasting and NDS localization suggest thatp-nitrophenyl α-galactoside hydrolase is located in or on the double-track membranes, primarily on the outer double track.

ISSN:0008-4166    

DOI:10.1139/m75-219

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Earlier work showed thatEscherichia colicontains at least two enzymes which reduce nitrofurazone and other nitrofuran derivatives. One of these enzymes is lacking in some nitrofurazone-resistant mutant strains. We now report that there are three separable nitrofuran reductases in this organism: reductase I (mol. wt. ~50 000, insensitive to O2), reductase IIa(mol. wt. ~120 000, inhibited by oxygen), reductase IIb(mol. wt. ~700 000, inhibited by O2).Unstable metabolites formed during the reduction of nitrofurazone by preparations containing reductases IIaand IIbproduce breaks in DNA in vitro. In vivo experiments with nitrofurazone-resistant strains, which lack reductase II but contain reductases IIaand IIb, demonstrated that lethality, mutation, and DNA breakage are all greatly increased when cultures are incubated under anaerobic conditions, i.e., conditions such that reductase II is active. These results provide further evidence for the importance of reductive activation of nitrofurazone.

ISSN:0008-4166    

DOI:10.1139/m75-220

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Levels of antituberculous immunity similar to those induced by live BCG vaccine were detected in CF1 mice immunized with ribosomal fractions isolated fromMycobacterium tuberculosisvar.bovis, strain BCG, and challenged 3 weeks later with the virulent H37Rv strain ofMycobacterium tuberculosisvar.hominis. The activity of the crude ribosomal preparations was found to be a function of the immunizing doses and the immunity induced by 1.0-mg doses remained at the same high level after 4 weeks of storage at 4 °C but decreased markedly thereafter. Dialysis and lyophilization had no detrimental effects on the activity of the crude preparations whereas purification by column chromatography on Sephadex G-200 annihilated their biological activity. Crude low-polysaccharide-containing preparations were found inactive even at the 1.0-mg dose level and results of experiments performed with crude ribosomal fractions of varying polysaccharide contents strongly suggest that polysaccharides, or RNA-polysaccharide complexes, may play an important role in the induction of immunity with crude ribosomal fractions isolated from the BCG strain ofMycobacterium tuberculosisvar.bovis.

ISSN:0008-4166    

DOI:10.1139/m75-221

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

An actinomycete, isolated as a contaminant of a culture medium containing 25% NaCl, has been classified asActinopolyspora halophilagen. et sp. nov. in the family Nocardiaceae. The morphology and biochemical characteristics of this organism distinguish it from other members of the family Nocardiaceae and other genera possessing a type IV cell wall. It requires high NaCl concentrations for growth and can grow in saturated NaCl. The lowest concentration permitting growth in liquid medium is 12%, and on solid medium, 10%. Colonies developing at lower salt concentrations contain holes resembling viral plaques. No growth occurred in a medium containing 30% KCl instead of NaCl. This organism can grow in simple media with NH4+salts as nitrogen source and different sugars and other compounds as carbon source. Though it has a salt requirement almost as great as the extremely halophilic rods and cocci, it differs from these in containing diaminopimelic acid and in sensitivity to lysozyme; both properties suggest that it has a mucopeptide cell wall. It also contains some phospholipids common to other actinomycetes, but does not contain any phytanyl ether linked lipids characteristic of other extremely halophilic bacteria.

ISSN:0008-4166    

DOI:10.1139/m75-222

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

The mixture of polysaccharides in the gelling component of agar (agarose) is hydrolyzed toD-galactose and 3,6-anhydro-L-galactose by a series of hydrolytic enzymes obtained fromPseudomonas atlantica. The final degradative step in the pathway of agarose decomposition is the hydrolysis of the α-linkage in the dissaccharide neoagarobiose yieldingD-galactose and 3,6-anhydro-L-galactose.Pseudomonas atlanticawhen grown on agar produces two specific enzymes,p-nitrophenyl α-galactose hydrolase and neoagarobiose hydrolase. The purification and partial characterization of both enzymes are presented.

ISSN:0008-4166    

DOI:10.1139/m75-223

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

The proteins of the cell envelope ofNeisseria siccastrain ATCC 9913 have been examined by SDS – polyacrylamide gel electrophoresis. Some 20 proteins were resolved from the total envelope fraction, and nearly all of these were found to be localized in the outer membrane. Preparations of the "free-endotoxin" fraction differ from the outer membrane only in lacking a few minor proteins.The behavior of several of the envelope proteins on electrophoresis can be modified by changing the temperature of sample solubilization, and also by alteration of the growth medium. Experiments with phosphate-limited cultures showed that certain periplasmic proteins are closely associated with free endotoxin.Mutations which result in altered outer membrane permeability to antibiotics were found to cause changes in cell envelope protein composition.A comparison of the envelope proteins of eight species of non-pathogenicNeisseriashowed that each had a characteristic composition. A classification of the organisms based on the relatedness of the protein patterns seen on SDS-polyacrylamide gels was in close agreement with classifications based on more usual methods.

ISSN:0008-4166    

DOI:10.1139/m75-224

出版商:NRC Research Press    

年代:1975

数据来源: NRC