Haloquadratum walsbyi : Limited Diversity in a Global Pond
Plasmid preparations from the three strains of Haloquadratum were separated by electrophoresis on 1% agarose gels and stained with ethidium bromide. Panel A: the plasmid bands labeled PL6 are super-coiled (sc), open-circular (oc) and dimeric forms of two, closely related, ∼6 kb plasmids (see text for details). The Bajool9 isolate of Haloquadratum  is also seen to carry a similarly sized plasmid as well as a much smaller one, running near the bottom of the gel. The position of contaminating, sheared chromosomal DNA is indicated at the right of each panel (chr). Panel B: more of the plasmid preparation from isolate C23T has been loaded, revealing the large plasmid, PL100. In both panels, MW indicates the 1 kb DNA size ladder (Invitrogen), with lengths indicated in kb at the left.