NUMBER AND HETEROGENEITY OF rRNA OPERONS IN RUMEN BACTERIAL MEMBERS FROM THE GENUS Prevotella | ŠTEVILO IN HETEROGENOST rRNK OPERONOV PRI VAMPNIH BAKTERIJSKIH VRSTAH IZ RODU Prevotella

English. The number of rRNA operons and internal spacer region heterogeneities in members of the rumen genus Prevotella were analysed. Chromosomal DNA from 20 strains belonging to P.ruminicola, P.albensis, P.bryanti and P.brevis was isolated, digested by five restriction enzymes, and hybridized with 16S and 23S rDNA probes. The resulting hybridization patterns indicate that P. albensis strains possess 4 or 5 rRNA operons, strains belonging to P. brevis possess 4 rRNA operons and P. bryantii strains 6 or 7 rRNA operons. Strains belonging to P. ruminicola probably possess 4 rRNA operons, with one exception having 6 or 7 rRNA operons. 16S-23S spacer region was also PCR amplified. The results suggest that there are at least three size variable 16S-23S spacer regions in P. albensis and P. brevis, two in P. ruminicola, and only one spacer region in P. bryantii.

Slovenian. Analizirali smo število operonov ribosomskih RNK in heterogenost internih medgenskih regij pri vampnih bakterijskih vrstah iz rodu Prevotella. Izolirali smo genomsko DNK dvajsetih sevov iz vrst P.ruminicola, P.albensis, P.bryanti in P.brevis in jo razrezali s petimi restrikcijskimi endonukleazami. Hibridizacijo smo izvedli s 16S in 23S rDNK sondami. Glede na število hibridizacijskih signalov lahko sklepamo, da imajo sevi vrste P. albensis 4 ali 5 rRNK operonov, sevi vrste P. brevis 4 rRNK operone, sevi vrste P. bryantii 6 ali 7 rRNK operonov. Vrsta P. ruminicola ima 4 rRNK operone, z izjemo enega seva, ki ima 6 ali 7 rRNK operonov. Namnoževanje regije med genoma za 16S in 23S rRNK je pokazalo, da so pri vrstah P. albensis in P. brevis vsaj tri različno dolge interne medgenske regije, pri vrsti P. ruminicola dve in pri vrsti P. bryantii samo ena.