ISSN:0008-4166    

DOI:10.1139/m81-084

出版商:NRC Research Press    

年代:1981

数据来源: NRC

ISSN:0008-4166    

DOI:10.1139/m81-085

出版商:NRC Research Press    

年代:1981

数据来源: NRC

ISSN:0008-4166    

DOI:10.1139/m81-086

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Sporulating colonies ofStreptomyces ipomoeawere observed using light and scanning electron microscopy. In addition to the open loops and spiral chains of spores characteristic ofS.ipomoea, globose structures resembling sporangia of the genusStreptosporangiumwere found. The "sporangia" had a smooth surface, were 5–6 μm in diameter, and consisted of an unbranched coiled hypha within an enveloping sheath. As the sporangia matured, septa formed in the internal sporogenous hypha forming coiled chains of spores morphologically similar to those formed on the typical spore chains. The sporangia germinated on agar, without releasing the nonmotile spores, by formation of several germ tubes at several locations on the sporangia.

ISSN:0008-4166    

DOI:10.1139/m81-087

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Changes in the identity and quantity of proteins synthesized during morphogenesis may result from alterations in gene expression in the dimorphic yeastCandida albicans. Stationary phase yeast cells, upon resuming growth at 25 °C, form budding yeast and at 37 °C form germ tubes. In order to identify proteins associated with morphogenesis, we compared cytoplasmic proteins synthesized during germ tube and bud formation. Proteins synthesized during this period were labeled at four intervals with either [3H]leucine or [35S]methionine and separated by two-dimensional polyacrylamide gel electrophoresis. This study shows that, of the 230 proteins resolved on each gel, 5 were specific to the yeast morphology and 2 proteins showed reduction in net synthesis in the mycelial phase. There were, however, no mycelium-specific proteins at any labeling period. The majority of proteins were common to both morphologies and showed no major shift in number during resumption of growth. The observations reported here suggest that differential gene expression occurs during morphogenesis ofC.albicans.

ISSN:0008-4166    

DOI:10.1139/m81-088

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

The direct agglutination of erythrocytes byNeisseria meningitidiswas studied as a marker for adherence. Hemagglutination (HA) was studied by slide test (5-min incubation) and by dilutions in microtitre plates (20-h incubation). Meningococci that were freshly isolated from subjects agglutinated only human cells by slide test but human, dog, rabbit, guinea pig, and rat cells were agglutinated in the microtitre system. Newly isolated strains were piliated and HA positive but pili were lost after 10 passages on agar, and bacteria became HA negative. HA could be maintained by "affinity culturing," which selected markedly adhesive bacteria: erythrocytes with adherent meningococci were isolated and cultured on agar. This procedure was repeated daily. HA titres were unaffected by mannose but were reduced by sonic disruption, trypsinization, ultraviolet irradiation, heating (65 °C), and formaldehyde. Encapsulated (serogroupable) bacteria had low HA titres compared with nongroupable strains, and purified capsular polysaccharides A and C inhibited HA. Meningococcal HA is probably mediated by pili and modified by other factors such as encapsulation. Colonial variation was not a reliable indicator of piliation, and HA is best used for this purpose.

ISSN:0008-4166    

DOI:10.1139/m81-089

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Marion's anerobic culture/set-A (Bio-Bag A) and the Baltimore Biological Laboratory (BBL) Gaspak anaerobic system were evaluated for their efficiency in the cultivation and recovery of anaerobes and capnophilic organisms from human dental plaque samples. Both culture systems were relatively efficient in supporting the growth of pure cultures of various bacterial species recently isolated from the human dental plaques. When the dental plaque samples were cultured the organisms commonly found were cultivatable in both culture systems. However, the counts and proportions ofFusobacterium nucleatumfrom the samples were significantly higher in Marion's culture system, whereas the proportions of black-pigmentedBacteroidessp. were significantly higher in the BBL anaerobic system.

ISSN:0008-4166    

DOI:10.1139/m81-090

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

An extracellular, acidic polysaccharide has been isolated from the culture medium of a spontaneous cellulose-negative strain ofAcetobacter xylinum. Chemical analysis shows that the polymer is composed of glucose, mannose, rhamnose, and glucuronic acid in a molar ratio approximating 3:1:1:1. No evidence for the presence of cellobiose units as structural parts in the polysaccharide has been found.

ISSN:0008-4166    

DOI:10.1139/m81-091

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Studies using Sephadex gel filtration indicated that the α and β2components of theBacillus subtilistryptophan synthase associate to form complexes under the appropriate conditions of buffer, pH, and temperature. Monovalent cations, glycerol, and the cofactor, pyridoxal-5′-phosphate, were required to maintain an active β2component, and in turn, affected the association of the α and β2components. Under conditions that stabilized the individual components during their purification, the affinity of the subunits for each other was weak. Under the same buffer conditions, but at the higher pH of 7.8 at which the enzymatic activities are assayed, the individual components readily associated. The substrate serine appeared to affect complex formation but there was no effect from the indole moiety. When the temperature was raised from 4 to 22–25 °C, complex formation was observed at both pH 6.6 and 7.8. The results of these experiments are consistent with the formation of αβ2and α2β2species as the associated tryptophan synthase complexes ofB.subtilis.

ISSN:0008-4166    

DOI:10.1139/m81-092

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

The effect of amino acids and derivatives, Krebs cycle acids and related compounds, fatty acids, and vitamins and related compounds on the toxicity of 8-quinolinol and bis(8-quinolinolato)copper(II) toAspergillus oryzae(ATCC 1011) was studied. Only aliphatic thiol-containing compounds (cysteine, glutathione, dithioerythritol, and dithiothreitol) and DL-α-lipoic acid protected against 8-quinolinol but not its copper(II) bischelate.It is suggested that 8-quinolinol inhibits lipoic acid biosynthesis, and the mode of fungitoxicity of 8-quinolinol is different from that of bis(8-quinolinolato)copper(II).

ISSN:0008-4166    

DOI:10.1139/m81-093

出版商:NRC Research Press    

年代:1981

数据来源: NRC