FIG. 3.

Assessment of the effect of environmental conditions upon the interaction between b-MVs and exogenous DNA. MVs were incubated with DNA (see Materials and Methods for details), and the effects of concentration of DNA (▪) (A), altered pH (▴) (B), and concentration of Na⁺ (○) or Mg²⁺ (•) cations, respectively (C), upon MV-DNA interactions were assessed. Note that for panel A, the ratio on the x axis is equal to the concentration of the assayed DNA/concentration of DNA in the matrix. Quantities of DNA (ng)/20 μg MV protein for R values of 1 were 116 ± 3 (DNA concentration; MVs only), 86 ± 3 (pH; MVs only), 275 ± 3 (Na⁺; MVs plus DNA only), and 236 ± 6 (Mg²⁺; MVs plus DNA only) (means ± standard deviations; n = 60).