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The hydrophobicity of Streptococcus salivarius strain HB and mutants deficient in adhesion to saliva-coated hydroxyapatite 总被引:1,自引:1,他引:0
The hydrophobicity and adhesion to saliva-coated hydroxyapatite of Streptococcus salivarius HB and the mutants HB7, HBV5 and HBV51 were measured. The mutants HB7 and HBV51 showed a significant reduction in adhesion to salivacoated hydroxyapatite and hydrophobicity compared with the mutant HBV5 and the parent strain. This supports the view that hydrophobic interactions are important for bacterial attachment in the oral cavity and is in contrast to previous studies on the hydrophobicity of these strains. 相似文献
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Haemagglutinins and Fimbriae in Different Serotypes and Biotypes of Yersinia enterocolitica 总被引:2,自引:2,他引:0
When cultured in static broth at 20°C, 46 of 115 strains of Yersinia enterocolitica , diverse in biotype and serotype, produced a broad-spectrum mannose-resistant (MR) adhesin that agglutinated the erythrocytes of all of 10 animal species examined. The production of haemagglutinin (HA) was associated with the presence of fimbriae of S nm diameter. Culture of HA+ strains at 37° resulted in the disappearance of haemagglutinating ability and loss of fimbrial production. Strains of Y. enterocolitica with K1 antigen produced an MR adhesin that agglutinated only fowl erythrocytes and was associated with fimbriae of 4–4.5 nm diameter. None of 14 strains of Y. pseudotuberculosis was haemagglutinating. 相似文献
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1. Thirteen Erwinia carotovora strains produced mannose-sensitive haemagglutinins associated with the presence of type-1 fimbriae.
2. Three fimbriate Er. rhapontici strains produced haemagglutinins of the mannose-resistant and eluting (MRE) type.
3. There were 12 Er. carotovora , 12 Er. atroseptica and 2 Er. chrysanthemi strains that produced no detectable haemagglutinins and were non-fimbriate. 相似文献
2. Three fimbriate Er. rhapontici strains produced haemagglutinins of the mannose-resistant and eluting (MRE) type.
3. There were 12 Er. carotovora , 12 Er. atroseptica and 2 Er. chrysanthemi strains that produced no detectable haemagglutinins and were non-fimbriate. 相似文献
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Sixty-two wild-type Salmonella typhimurium strains were characterized for their D-xylose enzyme activities. Strains from the xylose strong biogroup synthesized high levels of D-xylose isomerase and D-xylulokinase and transported D-xylose. Strains from the xylose weak biogroup synthesized only low levels of D-xylulokinase and low, or no, levels of D-xylose isomerase and were deficient in the ability to transport D-xylose. These findings are discussed in the light of known phylogenetic relationships among the biotypes of Salm. typhimurium. 相似文献
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ABSTRACT. An amoeba isolated from a wheatfield and a forest soil in Australia has been identified as Trichamoeba mycophaga n. sp. Trophozoites of this amoeba are palmate to elongate and measure 45–136 μm in length and 25–94 μm in width. Amoebae in continuous locomotion may be limax with a villous-bulb uroid. Both the lobose pseudopodia and the advancing margin of a limax trophozoite bear an ectoplasmic crescent. The plasma membrane is coated with an electron-dense amorphous layer ca. 100 nm thick. Endoplasm is granular with elongate to bipyramidal crystals and contains bacterial endosymbionts. Trophozoites have a single, spherical to oval nucleus, 4–10 μm in diameter, which contains a centrally located, spherical to oval nucleolus, 2.8–5.0 μm in diameter. The nucleoplasm contains aggregations of filaments distributed radially within the nuclear membrane. Cysts are 21–60 μm in diameter, with ecto- and endocyst walls separated by an amorphous layer. 相似文献
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Serological Identification of Hamster Oncornaviruses 总被引:12,自引:0,他引:12
ROBERT C. NOWINSKI LLOYD J. OLD PAUL V. O'DONNELL F. KINGSLEY SANDERS 《Nature: New biology》1971,230(17):282-284
CATS, mice and chickens have indigenous oncornaviruses (oncogenic RNA viruses) which induce leukaemias and sarcomas1,2. Mouse sarcoma virus (MuSV), like avian sarcoma virus, can induce sarcomas in the hamster3,4 but some of these MuSV hamster sarcomas release virus that differs both antigenically and with regard to its host range from the original5—it can be neutralized by antisera prepared against isolates of virus released from MuSV-transformed cells but not by antisera against murine leukaemia virus (MuLV) and it is sarcomagenic in hamsters but not in mice. Such a virus could be: (a) an indigenous hamster sarcoma virus “activated” by the inoculation of MuSV; (b) an MuSV genome that has acquired a new viral envelope from an indigenous hamster leukaemia virus (HaLV) during its sojourn in hamsters; or (c) a recombinant between HaLV and the sarcomagenic portion of the MuSV genome. In fact, it is known that the hamster possesses a virus (HaLV) which is morphologically similar to MuLV6,7. This virus lacks8 the group-specific (gs) internal MuLV-gs1 antigen characteristic of MuLV9,10 although it does have the gs antigen (MuLV-gs3) which is common to all mammalian leukaemia viruses investigated so far8. 相似文献
7.
RICHARD RODGERS THOMAS C. MERIGAN WILLIAM D. HARDYJUN. LLOYD J. OLD ROBERT KASSEL 《Nature: New biology》1972,237(78):270-271
TRANSMISSION of feline leukaemia can be accomplished with tissue extracts from cases which occur naturally1. Virus particles which are morphologically indistinguishable from the murine and avian C-type viruses are present in cats with the transmitted disease2. Feline leukaemia virus (FeLV) replicates in cat cell cultures3 and infected cells are demonstrable by the indirect immunofiuorescent antibody test which detects FeLV group-specific antigen as granular punctate fluorescence in the cytoplasm of acetone fixed cells4; this method allows easy quantitation of the antiviral effect of interferon. We report the production and assay of feline interferon using the fluorescent antibody test with FeLV infected cat cell cultures. 相似文献
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