Differential enumeration and in situ localization of microorganisms in the hindgut of the lower termite Mastotermes darwiniensis by hybridization with rRNA-targeted probes

We examined the abundance and spatial distribution of major phylogenetic groups of the domain Bacteria in hindguts of the Australian lower termite Mastotermes darwiniensis by using in situ hybridization with group-specific, fluorescently labeled, rRNA-targeted oligonucleotide probes. Between 32.0 +/- 7.2% and 52.3 +/- 8.2% of the DAPI-stained cells in different hindgut fractions were detected with probe EUB338, specific for members of the domain Bacteria. About 85% of the prokaryotic cells were associated with the flagellates of the thin-walled anterior region (P3a) and the thick wall of the posterior region (P3b/P4) of the hindgut, as shown by DAPI staining. At most, half of the EUB338-det…