FIG. 1.

The p-vac region and phenotypes of various H. volcanii transformants. (A) The 14 gvp genes constituting the p-vac region are shown as boxes (A and C through O). The four endogenous p-vac promoters are indicated by arrows underneath. The bars above represent the A, FG, and LM probes used for Northern analyses. The lines underneath represent colonies grown according to the gvp fragment(s) present in the cells. The M-O (entire p-vac region), L-O (ΔM), ΔA, and ΔC transformants harbor the p-vac region on a single construct (plus pJAS35 as a second construct); all other transformants contain the p-vac region on two constructs. Vac⁺ colonies appear turbid and white; orange, turbid colonies possess fewer gas vesicles, and dark red translucent colonies are Vac⁻. The Δ designations to the right of the plate indicate the deleted gvp genes. The constructs used for transformation are shown further to the right. The construction of transformants M-O, ΔA, ΔC, ΔN, and ΔO has been described previously (28, 29). (B) Various gene deletion transformants (top) in comparison to the respective control transformants (bottom). The colonies are arranged according to the respective gene deletion given underneath (i.e., M = ΔM transformant on top and cΔM control transformant underneath).