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Abstract
Summary: Some general characteristics of five phages (Mm1, ϕM2, ϕM3, Mm4 and Mm5) infecting Micromonospora are presented. All were naked, showing an icosahedral head and long non-contractile tail; they differed in their size and the presence of specific structures at the end of the tail. The phages were temperate, and four immunity groups were delimited (Mm4 and Mm5 were in the same group). Mm4 and Mm5 produced plaques on 13 of 20 strains of Micromonospora tested, whereas the remaining three phages could infect only Micromonospora sp. IMET 8002. No phage was able to infect any of four Streptomyces strains tested. Phages Mm4 and Mm5 both exhibited a buoyant density of 1.513 ± 0.002 g ml−1 in CsCl density gradients, and showed a similar pattern of structural polypeptides. All five phages had a single molecule of double-stranded DNA; their sizes (kb) were 50.6 (Mm1), 18.9 (ϕM2), 65.5 (ϕM3), 44.0 (Mm4) and 44.4 (Mm5), as determined after digestion with 13 restriction enzymes. The restriction patterns of Mm4 and Mm5 showed the presence of common size fragments.
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