TABLE 1.

16S rRNA-targeted oligonucleotide probes used in this study

Probe	Probe sequence (5′ to 3′)a	THb	Specificity	Reference
Univ 342	CTG CTG CSY CCC GTA G	55°C	All eubacteria	39
SRB 687	TAC GGA TTT CAC TCC T	55°C	Desulfovibrio	8
SRB 660	GAA TTC CAC TTT CCC CTC TG	55°C	Desulfobulbus	8
SRB 221	TGC GCG GAC TCA TCT TCA AA	55°C	Desulfobacterium	8
SRB 129	CAG GCT TGA AGG CAG ATT	55°C	Desulfobacter	8
SRB 814	ACC TAG TGA TCA ACG TTT	55°C	Desulfococcus	8
			Desulfosarcina
			Desulfobotulus

^aS is C or G, and Y is C or T. 

^bHybridization temperature and specificity were determined empirically (8, 15, 23).