FIG. 2.

Whole-cell FISH analysis of novel lineages of Aquificales in subsurface hot aquifer water (A and B) and a transmission electron micrograph of negatively stained cells of new isolate strain HGM-K1 (C). Microorganisms in the hot aquifer water were concentrated by filtration and fixed with 3.7% paraformaldehyde at the sampling time. Filtered microorganisms were hybridized with a fluorescein-labeled AF175 probe as described in Materials and Methods. Arrows indicate cells with Alexa Fluor 488 (A) and DAPI (B) signals and the polar flagellum of strain HGM-K1 (C). Scale bars: 5 μm (A and B); 0.4 μm (C).