Summary auto-generated
This study analyzed the 16S–23S rDNA spacer regions of three bacterial genera (Pectinatus, Selenomonas, and Zymophilus) isolated from breweries to clarify their phylogenetic relationships. Researchers amplified and sequenced these spacer regions from five bacterial species and discovered that each contained two types of spacer regions differing in size: long fragments (approximately 1.6 kb) and short fragments (approximately 1.4 kb). The long spacer regions contained one or two tRNA genes (alanine and/or isoleucine), while short spacer regions contained no tRNA genes. Notably, Pectinatus and Selenomonas species exhibited a reverse order of tRNA genes compared to previously documented patterns in other bacteria—with alanine tRNA preceding isoleucine tRNA rather than the opposite. Sequence homology analysis showed Pectinatus species were more closely related to Selenomonas lacticifex than to Zymophilus species based on long spacer analysis. However, short spacer analysis suggested different relationships, conflicting with both long spacer and 16S rRNA sequence data. These findings suggest that taxonomic classifications of anaerobic brewing bacteria warrant re-examination, as the long spacer tRNA gene order and sequences may provide more accurate phylogenetic information than short spacer regions or 16S rRNA sequences alone.
Key findings
- Two types of 16S–23S rDNA spacer regions (long and short) were identified in Pectinatus, Selenomonas, and Zymophilus species, with long spacers containing one or two tRNA genes and short spacers containing none
- Pectinatus and Selenomonas species displayed a previously unreported reverse order of alanine and isoleucine tRNA genes in their long spacer regions
- Long spacer sequence analysis indicated Pectinatus species are more closely related to Selenomonas lacticifex than to Zymophilus species, conflicting with 16S rRNA sequence analysis
- The tRNA gene order and long spacer DNA sequences may provide more accurate phylogenetic information than traditional 16S rRNA or short spacer analyses for these anaerobic brewing bacteria
This summary was generated automatically from the article PDF and is not part of the original publication. Refer to the PDF for the authoritative text.
Abstract
The 16S--23S rDNA spacer regions of two Pectinatus species, two Zymophilus species and one Selenomonas species were cloned after PCR amplification. The results of PCR amplification showed that these species had two types of spacer regions which differ in molecular size (long and short). Only the long spacer regions in these bacteria contained one or two tRNA genes (alanine and/or isoleucine). The spacer regions in these bacteria had a relatively high level of homology. Homology was particularly high for bacteria belonging to the same genus. Interestingly, the order of the two tRNA genes present in the long spacer regions of Pectinatus and Selenomonas was the reverse of that which had been previously reported for other bacteria. The results of spacer homology analysis and the order of the tRNA genes suggest that the taxonomic classification of anaerobic bacteria isolated from the brewing process should be re-examined.