摘要:

Among a number of carbohydrates studied, glucose, fructose, and sucrose were found to support adequate growth in fiveStaphylococcus aureusstrains selected for their different properties: toxinogenic Wood 46, auxotrophic Wood 46 thy−, encapsulated Smith, penicillin-resistant Saskatchewan 755, and non-toxinogenic and coagulase-negative SA-13.In all these strains, the analog 2-deoxy-D-glucose (deGlc), when included in the culture medium inhibited growth by blocking the use of sucrose or fructose almost completely;D-glucose restored normal growth. A Wood 46 thy−strain was more specifically used to study the effects of deGlc on "balanced and unbalanced" growth and formation of toxin. When added at the beginning of the logarithmic phase of growth in the presence of thymine, deGlc lowered the growth rate of the cells; on the other hand, as expected, penicillin (affecting formation of cell wall and used here for comparison purposes) had a truly killing effect. Thymineless death associated with "unbalanced" growth was inhibited by deGlc and this inhibition was not significantly reversed by glucose. The cells were observed under the fluorescence microscope, after staining with conjugates of rhodamine and lysozyme, as well as with those of fluorescein and anti-Staphylococcus aureusrabbit serum. When grown in the presence of deGlc, the cells were seen as unevenly stained fluorescent dots, while some of those treated with penicillin or undergoing thymineless death appeared as large and amorphous fluorescent bodies, unlike the untreated cells; such changes due to deGlc or penicillin could possibly involve carbohydrate-containing antigens (e.g., mucopeptide and teichoic acid). The results obtained with the use of various standard techniques to detect toxin indicated that toxin formation is inhibited by deGlc, apparently not selectively but proportionately with growth.

ISSN:0008-4166    

DOI:10.1139/m71-215

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Several concentrations of yeast extract, beef extract, and fetal bovine serum were compared for ability to elute adsorbed coxsackievirus B5 and poliovirus 1 from HA cellulose nitrate Millipore membrane filters. Elution improved with increases in concentration of eluting agent and volume of eluent. The eluent of choice was undiluted fetal bovine serum because it was compatible with cells and showed a high degree of elution. A 5-ml serum eluate resulted in the recovery of 80–90% of the virus adsorbed by a filter from an infected buffered saline sample.

ISSN:0008-4166    

DOI:10.1139/m71-216

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

From a population of cells ofPseudomonas aeruginosasensitive to 33 parts per million (ppm) of quaternary ammonium compound (QAC) and to 0.1 mg/ml of chloramphenicol (CAP), pure strains resistant to 750 ppm and 2.5 mg/ml of these antibacterial substances were isolated. Lipids from the sensitive and resistant cells grown under various conditions were extracted and characterized. Increased lipid biosynthesis was investigated as a possible factor in the resistance of this bacterium to CAP and QAC.Resistant cells grown in medium containing 207 ppm QAC at 25C averaged 77% more total lipid than sensitive cells. Resistant cells grown in the absence of QAC at 25C retained their resistance and averaged 27% more total lipid than sensitive cells. Cells grown at 32C in the presence of QAC contained 8% more total lipid than sensitive cells but less than cells grown at 25C under the same conditions. There was no increased lipid production by QAC-resistant cells grown at 37C in a Fermacell fermentor. Cells grown in CAP-containing medium (2.5 mg/ml) at 25C developed 28% more total lipid than sensitive cells grown in antibiotic-free medium.Gas–liquid chromatograms of the phospholipid, free fatty acid, and triglyceride fractions of the various cell types indicated that the same fatty acids were present. There was a 10% increase of the C18:1 fatty acid in both the phospholipid and free fatty acid fractions of the free lipids of cells grown in a Fermacell fermentor in the presence of CAP or QAC. However, there was no compensatory decrease in any single fatty acid, but rather a general decrease.SensitiveP.aeruginosacontained 14% free lipid and 3% to 6% bound lipid. The major phospholipid was phosphatidyl ethanolamine, which constituted 59% of the total phospholipid fraction of the sensitive cells. Analysis of fatty acids revealed that C16 amounted to 34%, C18:1 19%, and C16:1 and C18 each about 5% of the total present. These four fatty acids accounted for 63% of the free lipid present in the sensitive cells.

ISSN:0008-4166    

DOI:10.1139/m71-217

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Purified enterotoxin C2was fractionated by isoelectric focusing into three toxic and immunologically identical components having isoelectric points of 6.65, 5.90, and 5.50.

ISSN:0008-4166    

DOI:10.1139/m71-218

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

A species ofCephalosporiumand another ofFusariumwere grown for 5 years on a medium devoid of any known, complex, organic carbon source. The organisms were grown on a solid as well as in a liquid medium and the growth rates under various conditions, based on increase in spore number and dry weight, were recorded. At initial stages of growth, there was a linear relationship between the rate of growth and CO2gas and (or) HCO3−supplied. Direct evidence for assimilation of C14from C14O2was demonstrated through combustion analyses. Nitrogen supplied as either NH4Cl or KNO3supported growth and C14O2fixation. Although grown as heterotrophs, both species of fungi retained their ability to grow autotrophically or mixotrophically. Laboratory air, purged through sulfuric acid to eliminate trace organic contaminants from the air, supported growth of theCephalosporiumsp.

ISSN:0008-4166    

DOI:10.1139/m71-219

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Stationary-phase cultures ofStreptococcus lactis(strain 1) ere used to produce basic peptides which had no antibiotic activity but which contained material electrophoretically similar to nisin. Cells ofS.lactis(strain 354/07) which produce nisin in late log phase and stationary phase were harvested in early log phase and used for preparing cell extracts (C.E.). Incubation of C.E. with basic peptide preparations from strain 1 generated an antibiotic believed to be nisin. The amount generated was directly related to one of the peak areas in the electrophoretograms of the basic peptide preparations. It is suggested that material in this peak is similar to or is a precursor of nisin. The specific activity of the C.E. was highest when a mild disruption method was used which affected neither the phase-contrast appearance nor the Gram reaction of the organism.

ISSN:0008-4166    

DOI:10.1139/m71-220

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The polysaccharide moieties of the lipopolysaccharides of serotyped strains ofProteushave been examined. The strains were selected to provide a wide range of serotypes. The primary acetic acid extracts of different strains ofProteuswere fractionated on Sephadex G-50 and yielded three main components: a peak (I), which was composed mainly of polysaccharide; a second peak (II), the core polysaccharide, which contained heptose and phosphate; and a third component (III), which corresponded to a low molecular weight fraction and contained KDO and phosphate as well as other components. Peak I was not encountered in rough strains ofProteus. The chemical composition of the peaks obtained for S, SR, and R strains is discussed in relation to their agglutinating ability to homologous antiserum.

ISSN:0008-4166    

DOI:10.1139/m71-221

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Antibiotic activity ofArmillaria mellea(Vahl ex Fr.) Kummer towards many fungi and bacteria, including some very important plant pathogens, was clearly established. Preliminary extraction trials have been negative. No direct relationship was found between the bioluminescence ofA.melleaand its antibiotic activity.Clitocybe tabescens(Scop, ex Fr.) Bres. also possesses antibiotic capability, but to a much lower degree.

ISSN:0008-4166    

DOI:10.1139/m71-222

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The fungusCyathus helenaeBrodie (Gasteromycetes) produces a complex of antibiotic substances collectively called cyathin. Highest yields were obtained when the fungus was grown at room temperature for 25 days on a chemically defined liquid medium in static culture. The action spectrum of cyathin (and its components) was determined by placing cyathin-bearing paper discs on agar plates seeded with the microorganisms being tested. The cyathin complex is active against actinomycetes, bacteria (gram-positive as well as gram-negative), and some fungi, including dermatophytes. Weaker antimicrobial activity is also shown byC.striatus(Huds.) Willd. ex Pers.,C.poeppigiiL., andC.limbatusL. Seven different compounds have been isolated from the cyathin complex: 2,4,5-trihydroxybenzaldehyde (C7H6O4),cyathin A3(C20H30O3), cyathin A4(C20H30O4),allocyathinA4(C20H30O4),cyathin B3(C20H28O3), cyathin B4(C20H28O4), and cyathin C5(C20H26O5). Aside from 2,4,5-trihydroxybenzaldehyde, these compounds appear not to have been previously described. A discussion of some of the structural features of cyathin A4and cyathin A3is presented

ISSN:0008-4166    

DOI:10.1139/m71-223

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Cell-free culture filtrates ofAgrobacterium rhizogenessignificantly increased adventitious root initiation in a mung bean hypocotyl bioassay. These filtrates were most active from cultures at their maximum cell density; the root-inducing activity declined rapidly after this time. The contents of cells disrupted by sonification were not active nor did they increase the activity of a 6-day-old culture filtrate. The root-inducing factor was heat stable, apparently dialyzable, and antagonized by kinetin. The 3-indole-acetic acid concentration of the culture filtrates was not high enough to account for the number of roots formed.

ISSN:0008-4166    

DOI:10.1139/m71-224

出版商:NRC Research Press    

年代:1971

数据来源: NRC