57 research outputs found

    The Physics of the B Factories

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    Genetic homogeneity and phage susceptibility of ruminal strains of Streptococcus bovis isolated in Australia

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    The genetic homogeneity of 37 strains of ruminal streptococci was investigated by comparing DNA fragment profiles on agarose gels following restriction endonuclease digestion with Hae III, Cfo I and Msp I. Thirty strains were indistinguishable from Streptococcus bovis strains, 2B, H24 and AR3. The remaining three strains were similar but not identical to a ruminal strain of Strep. intermedius (AR36). In addition, the susceptibility of these strains to infection by five bacteriophages was examined. Three of the phages (φSb02, φSb03 and φSb04) were specific to the strain of Strep. bovis from which they were isolated, while phages 2BV and φSb01 infected one and two strains, respectively, in addition to their primary host. It was concluded that although Strep. bovis is relatively homogeneous genetically, broad host range phages appear to be uncommon with this bacterial species

    Bacteriophages that infect the cellulolytic ruminal bacterium Ruminococcus albus AR67

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    Aim: To isolate bacterial viruses that infect the ruminal cellulolytic bacterium Ruminococcus albus. Methods: Four phages infecting R. albus AR67 were isolated under anaerobic conditions using the soft-agar overlay technique. The phages were characterized on morphology, solvent stability, nucleic acid type and digestion characteristics. Two phages, Ra02 and Ra04 comprised icosahedral virions with linear double-stranded DNA and appeared to belong to the family Tectiviridae. The other two phages are most likely filamentous phages with circular single-stranded DNA of the family Inoviridae. Significance of the Study: Viruses of the families Tectiviridae and Inoviridae have not previously been isolated from rumen bacteria. The phages isolated in this study are the first phages shown to infect the cellulolytic bacteria of the rumen. This suggests that the cellulolytic populations of the rumen are subject to lytic events that may impact on the ability of these bacteria to degrade plant fibre and on the nutrition of the animal
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