摘要:

Four phages isolated from carrier strains ofClostridium perfringenstype C belong to two classes. The three phages of class I, c1, c3, and c4, are homoimmune and serologically closely related. The phage of class II, c5, is heteroimmune to the class I phages and not related to them serologically. Transduction experiments with several of the phages were negative. Mutants of the indicator strain with surface alterations occurred spontaneously in stock cultures. Electron micrographs show the phages of each class to be distinct yet similar, having polyhedral heads of about the same diameter 55 nm, and long, flexible tails without sheaths or collars. Phages c4 and c5 were characterized for their lysogenic properties. Phage c4 was inducible with mitomycin C. Both c4 and c5 were temperate viruses by the test of stability of their respective lysogens to phage-specific antisera.

ISSN:0008-4166    

DOI:10.1139/m76-090

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Azotobacter chroococcum(ATCC 7493) was grown in continuous culture with intense vortex aeration (stirring rate 1750 rpm) with up to 50% O2in the gas phase. Under these conditions the dissolved O2generally remained at zero while the cell growth rose to about twice the normally accepted value. The meaning of the term "O2-limitation" in N2-fixingA.chroococcumcultures is critically examined.

ISSN:0008-4166    

DOI:10.1139/m76-091

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The filament, that is helically arranged to form the bacterial spina, is composed of morphological subunits (oligomers) about 5.6 nm in width and 11 nm in length. The oligomers are asymmetrical in that the inner surface is grooved. Image analysis of negative-stained spinae ribbons indicates that the oligomers are paired, possibly beaded structures, the arrangement of which is easily distorted during preparation. In intact spinae, the oligomer orientation may be normal to the filament axis, but in collapsed freeze-etched spinae, the oligomers are inclined at a constant angle of about 72° to the filament axis.

ISSN:0008-4166    

DOI:10.1139/m76-092

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Four coliform estimation procedures were compared as to their ability to enumerate coliform bacteria (oxidase-negative lactose fermenters) from sewage, effluent, and various fresh waters in the lower Great Lakes Region of Canada. Two of the procedures used and which are cited in the American Public Health Association (APHA) Standard Methods were a most probable number (MPN) technique using lauryl tryptose broth (LST) and brilliant green bile 2% broth (BGB), and a membrane filtration (MF) technique using m Endo agar LES. The other two procedures were an MPN technique using Parhad chemically defined synthetic medium (PCDS) and BGB developed for Indian fresh waters and an MF (mC agar) technique developed for seawater.Data indicate that within the survey area, maximum population estimates were achieved by the MF procedure using m Endo agar LES and that each procedure was selective for different genera of the Enterobacteriaceae. Discussions concerning standard versus reference procedures are presented.

ISSN:0008-4166    

DOI:10.1139/m76-093

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Fusarium oxysporum albediniswas grown in the presence of 20 different sugars or their derivatives. The results obtained were correlated with the stereochemical structure of the main oses. Osmotic phenomena as well as active and selective transport were used to explain differences in utilization of oses of very near structure. Based on the affinity of the fungus for mannose, a hypothesis is formulated concerning the fungus action in the host. [Journal translation]

ISSN:0008-4166    

DOI:10.1139/m76-094

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Phleomycin-stimulated solubilization ofEscherichia coliDNA is inhibited by infecting the cells with mutants of bacteriophage T4 before treatment with the antibiotic, inhibition requiring phage-specified protein synthesis. Two different modes of inhibition can be differentiated by infecting with mutants which are defective in an early state (genedenA−; endonuclease II-independent inhibition) or a late stage (gene 46−; endonuclease II-dependent inhibition) of phage-directed degradation of host DNA. Endonuclease II-independent inhibition results from interference with phleomycin-induced release of host DNA from the cytoplasmic membrane. In the presence of endonuclease II, the host DNA is converted to fragments, with average molecular weights of 106daltons, the further degradation of which is not promoted by continuous exposure of the cells to phleomycin.

ISSN:0008-4166    

DOI:10.1139/m76-095

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

A procedure involving the use of citrate-buffered lactose broth (pH 6.5) containing an analogue of a β-galactoside (4-chloro-2-cyclopentylphenyl β-D-galactopyranoside) has been developed for the enrichment ofShigellain competition with a 100-fold higher population ofEscherichia coli. The system makes use of the β-galactosidase activity ofE.coliwhich hydrolyzes the phenolic derivative of β-galactoside to galactose and an aglycone moiety (4-chloro-2-cyclopentylphenol) which is toxic toE.colibut is tolerated byShigella. The procedure is particularly effective in the enrichment ofS.sonneiandS.flexneri;S.dysenteriaeandS.boydiiare enriched to a lesser extent.

ISSN:0008-4166    

DOI:10.1139/m76-096

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

About 95 microorganisms, mainly streptomycetes, were examined for prodiginine pigments. The test methods, including some media for stimulating pigment production, are given. All nine strains which produced prodiginine pigments were characterized and the pigments identified. The results were used to propose structures for five prodigiosin-like pigments from actinomycetes reported in the literature between 1947 and 1964.Streptoverticilliumsp. 26-1 furnished good yields of butylcycloheptylprodiginine (I), whose antimicrobial activity is given.

ISSN:0008-4166    

DOI:10.1139/m76-097

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Several chemicals used as nitrification inhibitors were tested to determine their effect on denitrification by aPseudomonassp. and in soil. Denitrification by the bacterium was suppressed by 2-chloro-6-(trichloromethyl)-pyridine (N-Serve) at a concentration of 50 ppm, while 2,5-dichloroaniline caused the accumulation of nitrite in the culture medium. The nitrification inhibitors had little effect on the denitrifying activity in soil under anaerobic conditions. 2-Sulfanilamidothiazole inhibited denitrification to some extent and samples supplied with potassium azide produced N2O rather than N2as the predominant gas.

ISSN:0008-4166    

DOI:10.1139/m76-098

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Twenty-seven of 37 non-toxigenic, urease-negative strains originally identified asClostridium bifermentansthat were isolated in the Antarctic were reidentified asC.sordelliiby the tests for DNA–DNA homology, by the absence of mannose in the cell wall, and by growth inhibition of mannose. The test for cell wall sugar components of urease-negative and -positive strains ofC.sordelliirevealed that glucose, mannose, and rhamnose could not be detected in any of eight urease-negative strains used but galactose was detectable in seven of the eight strains and that glucose or galactose or both of the two sugars were present in the urease-positive strains tested.

ISSN:0008-4166    

DOI:10.1139/m76-099

出版商:NRC Research Press    

年代:1976

数据来源: NRC