Figure 3. The application of common approaches designed to ameliorate non-specific fluorescence in situ hybridization (FISH) probe binding failed to inhibit hybridization to granular gland cells (Gc) and spirocysts (Sp).

Cy3 (A), Cy5-labelled NonEUB338 (B) and Atto 647-labelled Vib-GV (C) FISH probes all hybridized to spirocysts. Blocking solution also failed to prevent non-specific binding of oligonucleotide probes to granular gland cells (D). Scale bars represent 100 µm in (A)–(C) and 50 µm in (D). Abbreviations: Gc, granular gland cell; Sp, spirocysts; and Symb, Symbiodinium.