In situprobing of Gram-positive bacteria with high DNA G + C content using 23S rRNA-targeted oligonucleotides Roller, Carsten and Wagner, Michael and Amann, Rudolf and Ludwig, Wolfgang and Schleifer, Karl-Heinz,, 140, 2849-2858 (1994), doi = https://doi.org/10.1099/00221287-140-10-2849, publicationName = Microbiology Society, issn = 1350-0872, abstract= 23S-rRNA-targeted oligonucleotide probes were designed for the phylogenetic group ‘Gram-positive bacteria with high G + C content of DNA’ (GPBHGC). A sequence idiosyncrasy in two adjacent base pairs in the stem of helix 69 in domain IV of the 23S rRNA is present in all hitherto analysed strains of GPBHGC. An oligonucleotide probe targeted to this region hybridized only with strains of GPBHGC and was successfully used for in situmonitoring of these cells in activated sludge. Another unique feature of the 23S rRNA molecules of GPBHGC is a large insertion in domain III. Fluorescent oligonucleotides targeted to the highly variable regions of the rRNA within the insertions of Corynebacterium glutamicumDSM 20300T, Aureobacterium testaceumDSM 20166 and Brevibacteriumsp. DSM 20165 hybridized specifically to their target strains, whereas probing with oligonucleotides complementary to the rRNA-coding strand of the 23S rDNA and to the spacer between 16S and 23S rRNA of C. glutamicumdid not result in detectable fluorescence. This confirmed that the large 23S insertions are indeed present in 23S rRNAs of GPBHGC and provide potential target sites for highly specific nucleic acid probes., language=, type=