FIG. 1.

Integrons in SGI1 and variants. The map of In104, the integron in the original SGI1, was generated from the sequence in GenBank accession no. AF261825. For SGI1-H, the cassettes from AY458224 were substituted on the left. The complete sequence of the integron in SGI1-K and its immediate surroundings is from this study (AY463797.3). Dashed lines represent the surrounding SGI1 backbone, and the medium-width line on the right represents the adjacent chromosome. Narrow vertical bars represent the inverted repeats (IRi and IRt) of class 1 integrons. The 5′-CS, 3′-CS, and tni regions of class 1 integrons are indicated by lines of different thicknesses, with attI1 as a tall open box and gene cassettes as open boxes with a black bar at one end, indicating the 59-base element (59-be). IS6100 and the central, non-integron-derived region are open boxes. Arrows indicate the position and orientation of genes and open reading frames, which are named or numbered.