Fig 3.

Expression of virulence proteins and the hyaluronic acid capsule. (a) SpeB production was detected in stationary-phase culture supernatants. Lanes: 1, 5448; 2, SF370-Sm^r; 3, SF370-Sm^r(ϕ5448.3 Cm^r); 4, SF370-Sm^r(ϕ5448.3 Sda⁺). (b) SpeC expression in mid-log-phase (A₆₀₀, 0.4) culture supernatants. All lysogens expressed both SpeB and SpeC, as expected. (c) Sda1 expression in mid-log-phase (A₆₀₀, 0.4) culture supernatants. (d) Hyaluronic acid capsule production was examined using the Stains-All method (29). The three M1 strains SF370-Sm^r, SF370-Sm^r(ϕ5448.3 Cm^r), and SF370-Sm^r(ϕ5448.3 Sda⁺) produced comparable amounts of hyaluronic acid capsule, greater than the amount produced by the M1T1 strain 5448. Bars indicate means; error bars, standard deviations (n = 3).