Figure 1 (Upper) A fanciful diagram to represent all members of the Inoviridae family (from A. Kornberg and T.A. Baker (1991). DNA Replication, 2nd edn. W.H. Freeman, New York; with permission); the gene numbering is for the closely related inoviruses f1, fd and M13 (often referred to, collectively or individually, as Ff phage). (Center) Negative contrast electron micrograph E. coli phage fd showing the differing end morphologies. Bar represents 100 nm; magnification about 180,000× (from C. Gray et al. (1981). J. Mol. Biol., 146, 621–627). (Lower) Electron micrograph of innumerable copies of the plectrovirus species Spiroplasma phage SpV1 extruding from the membrane of S. citri; magnification 60,000×
(reproduced from Renaudin, J. and Bove, J.M. (1994). Adv. Virus Res., 44, 429–463; with permission of Elsevier).
Figure 2 Linear presentations of circular genomes of non-integrative E. coli phage M13 (Upper, 6.4 kb), and integrative Vibrio phage CTXϕ (Lower; 6.9 kb). They are organized in modules of replication genes (red), structural genes (green) and morphogenesis genes (blue). Gene numbers and names are from classical genetic mapping studies Gene 10 (DNA replication) and gene 11 (morphogenesis) are derived translationally from the C-terminal thirds of genes 2 and 1, respectively. Note the loci of the cholera toxin subunits A and B correspond to the locus of g4 in M13 and that the repressor RstR is expressed from the complementary strand.
(Adapted from Faruque, S.M. and Mekalanos, J.J. (2005). J. Bacteriol., 187, 4095–4103; with permission).