FIG. 3.

Neighbor-joining tree showing the phylogenetic affiliation of the Thiomicrospira isolates (strain Milos-T1 and Milos-T2), and of Thiomicrospira spp. present in MPN cultures (indicated by the annotation Tms-MPN/Milos), both from the shallow-water hydrothermal vent site near Milos. ML-1 is the sequence from the excised DGGE band, which had the same position in the gel as the band of Thiomicrospira sp. strain Milos-T2. Tms-MPN/JB sequences were obtained from Thiomicrospira spp. present in MPN cultures of an intertidal mud flat of Jadebusen Bay, Germany, and are published elsewhere (3). The tree is created after comparison of partial (700-nucleotide) 16S rRNA sequences. Sequences marked with an asterisk are molecular isolates. The sequences determined in this study are shown in bold; A to D refer to the different zones around the vent (30 cm, 117 cm [core I], 117 cm [core II] and 200 cm [Fig. 1]); Roman numerals I to IV refer to the different layers (from surface to 16 to 26 mm deep); and Arabic numbers refer to the different MPN dilutions.