NONRANDOM FRAGMENTATION OF RIBOSOMAL-RNA IN HELICOBACTER-PYLORI DURING CONVERSION TO THE COCCOID FORM

The integrity of DNA and ribosomal RNAs in exponentially growing (baci llary) and ageing stationary phase (coccoid) cultures of Helicobacter pylori type strain CCUG 17874 was investigated. Extensive non-random f ragmentation of rRNAs was observed during the conversion to the coccoi d form. Beside a small proportion of full-length 16S and 23S rRNA that was always present, the majority of both 16S and 23S rRNA molecules s howed distinct highly specific fragmentation patterns. The 16S rRNA fr agmentation was characterised in detail by means of Northern blot and primer extension analysis. One cleavage site was located within the hi ghly conserved U5 region (position about 920). The results could not b e attributed to the presence of intervening sequences in the 16S and 2 3S rRNA genes. (C) 1998 Federation of European Microbiological Societi es. Published by Elsevier Science B.V. All rights reserved.