Phages C-2 and J: IncC and IncJ Plasmid-Dependent Phages, Respectively

Abstract

Phages C-2 and J were isolated from sewage. Phage C-2 was filamentous and formed plaques on Salmonella typhimurium strains carrying various C plasmids. It also plated on Proteus mirabilis and Serratia marcescens strains carrying particular C plasmids, but failed to form plaques on lines of Escherichia coli K12 strains harbouring most of these plasmids, although in all cases, phage multiplication on the strains was demonstrated. No phage increase occurred in any strain which lacked a C plasmid or contained plasmids of other incompatibility groups. The phage was sensitive to chloroform and, unlike other filamentous bacterial viruses, adsorbed to shafts of conjugative pili. It had a disc-like structure at the end which attached to the pilus. Phage C-2 had a buoyant density of 1.30 g cmd3 and a single-stranded circular DNA genome of 3.0 MDal. Phage J had an hexagonal head with an inter-apical distance of 40nm and a short noncontractile tail. It was resistant to chloroform and diethyl ether. The phage formed plaques or propagated on E. coli strains harbouring some IncC plasmids and all IncJ and IncD plasmids tested. The phage did not form plaques but propagated on P. mirabilis and Ser. marcescens strains carrying these plasmids. It did not plate or propagate on S . typhimurium strains harbouring the plasmids. The plaques were very hazy and variable in size. The phage attached sparsely, at a site which appeared to be located at the base of the tail, to sides of conjugative pili.

Genomics of Bacterial and Archaeal Viruses: Dynamics within the Prokaryotic Virosphere

“…For example E. coli-infecting inoviruses and leviviruses adsorb to the tip and to the sides, respectively, of the conjugative pili encoded by the F plasmid (IncF group) (275,289), while PRD1-like tectiviruses and levivirus PRR1 are known to use the cell envelope-associated DNA transfer complex encoded by the IncP group plasmids (95,96,191). Similarly, a tailed bacteriophage, podovirus J, was reported to adsorb to the sides of plasmid-encoded pili (26). Plasmids, on the other hand, might encode factors that abolish viral replication in a number of different ways (45,69,114,282).…”

Bacteriophage X-2: a Filamentous Phage Lysing IncX-Plasmid-harbouring Bacterial Strains

“…Strain JE2571, carrying the IncFl plasmid R386 (Dennison, 1972) was the indicator for phage fd (see below). Other plasmids belonging to Inc groups C (Sirgel et al, 1981), D (Coetzee et al, 1985a), HI and HI1 (Coetzee et al, 19853), J (Bradley et al, 1982a), S (Coetzee et al, 1986) and T (Bradley et al, 1981 b ;Coetzee et al, 1987) were also used in phage host-range experiments. Constitutive production of conjugative pili by the above plasmids was assessed by the ability of corresponding plasmid-specific phages, described in the same references, to form plaques on lawns of the plasmid-bearing organisms.…”

“…Techniques for visualizing phage-pilus and bacterium-phage mixtures were as described by Bradley (1980) and Bradley et al (1981aBradley et al ( , 1982a. For immune electron microscopy, grid-labelling with antiserum to phages X, X-2 (see Results) or IKeh (anti-IKeh kindly supplied by R. B.…”

“…Apart from its specificity for IncX-harbouring bacteria, it differed from other filamentous phages in other respects: phage X has a frankly curly appearance (Bradley et al, 198 1 a ; compared to filamentous phages like f 1 (Caro & Schnos, 1966), IKe (Khatoon et af., 1972;, PR6FS (Bradley, 1983), C-2 (Bradley et al, 1982a), SF (Coetzee et al, 1986) and tf-1 (Coetzee et al, 1987). Secondly the phage had a very broad host range in that it plated on bacterial strains harbouring plasmids of Inc groups 12, M, N, P-1, U and W. This host range partially overlaps that of phages IKe and It-2 (Coetzee et al, 1982) and these phages are here named X-like for that reason (see Bradley et al, 1983).…”

Escherichia coli tolQ Mutants Are Resistant to Filamentous Bacteriophages That Adsorb to the Tips, not the Shafts, of Conjugative Pili

“…Levy; see Bradley & Whelan, 1985), pAr-32 (Bradley et al, 19826) and R687 (IncD; see Datta, 1979). Strain TPS-2(R687) gave poor clearing in spot tests with phage fd, so the plasmid could not be used in some experiments.…”