Table 1.

Probes used for FISH.

Probe	Standard probe namea	Specificity	Sequence/5′ modification	Target RNA	Positionb,c	Formamide percentage/ incubation time (h)/probe concentration (ng µl−1)	Reference
EUB338	S-*-BactV-0338-a-A-18	Most bacteria	5′-GCT GCC TCC CGT AGG AGT-3′/fluorescein	16S	338–355	35–40%/1.5–o.n./3	Amann et al. (1990)
GAM42a	L-C-gProt-1027-a-A-17	Gammaproteobacteria	5′-GCC TTC CCA CAT CGT TT-3′/Cy5	23S	1027–1043	35–40%/1.5–o.n./3	Manz et al. (1992)
Rcas470	S-Rob1s-0471-a-A-21	Robbea sp.1 symbiont	5′-TGC GTA ACG TCA AGA CCC TGG-3′/Cy3	16S	471–491	25%/1.5/3.8	This study
Rss456	S-*-Rob2s-0457-a-A-21	Robbea sp.2 symbiont, Inanidrilus leukodermatus endosymbiont 1 (GenBank Accession No. AJ890100)	5′-ACC CTG AGC TAT TAA CCC AAG-3′/Cy3	16S	457–477	35%/o.n./4	This study
Rhs465	S-Rob3s-a-A-21	Robbea sp.3 symbiont	5′-AAC GTC AGG ATC CCG AGC TAT-3′/Cy3	16S	466–486	40%/3/2.3	This study
NON338	Not named	Negative control	5′-ACT CCT ACG GGA GGC AGC-3′/Cy3	16S	338–355	35–40%/1.5–o.n./3	Wallner et al. (1993)
BET42a	L-C-bProt-1027-a-A-17	Betaproteobacteria	5′-GCC TTC CCA CTT CGT TT-3′/fluorescein	16S	1027–1043	35–40%/1.5–o.n./3	Manz et al. (1992)

^aAccording to Alm and colleagues (1996).

^b16S rRNA position, Escherichia coli numbering (Brosius et al., 1978).

^c23S rRNA position, E. coli numbering (Brosius et al., 1981).

o.n., overnight.