Phylogenetic and Molecular Characterization of a 23S Ribosomal-Rna Gene Positions the Genus Campylobacter in the Epsilon-Subdivision of the Proteobacteria and Shows That the Presence of Transcribed Spacers Is Common in Campylobacter Spp

The nucleotide sequence of a 23S rRNA gene of Campylobacter coli VC167 was determined. The primary sequence of the C. coli 23S rRNA was deduced, and a secondary-structure model was constructed. Comparison with Escherichia coli 23S rRNA showed a major difference in the C. coli rRNA at approximately position 1170 (E. coli numbering) in the form of an extra sequence block approximately 147 bp long. PCR analysis of 31 other strains of C. coli and C. jejuni showed that 69% carried a transcribed spacer of either ca, 147 or ca. 37 bp. Comparison of all sequenced Campylobacter transcribed spacers showed that the Campylobacter inserts were related in sequence and percent G+C content. All Campylobacter strains carrying transcribed spacers in their 23S rRNA genes produced fragmented 23S rRNAs. Other strains which produced unfragmented 23S rRNAs did not appear to carry transcribed spacers at this position in their 23S rRNA genes. At the 1850 region (E. coli numbering), Campylobacter 23S rRNA displayed a base pairing signature most like that of the beta and gamma subdivisions of the class Proteobacteria, but in the 270 region, Campylobacter 23S rRNA displayed a helix signature which distinguished it from the alpha, beta, and gamma subdivisions. Phylogenetic analysis comparing C. coli VC167 23S rRNA and a C. jejuni TGH9011 (ATCC 43431) 23S rRNA with 53 other completely sequenced (eu)bacterial 23S rRNAs showed that the two campylobacters form a sister group to the alpha, beta, and gamma proteobacterial 23S rRNAs, a positioning consistent with the idea that the genus Campylobacter belongs to the epsilon subdivision of the class Proteobacteria

Techniques for production and detection of 23S positronium

In this work, we show recent measurements of 23S long-lived positronium production via spontaneous decay from the 33P level. The possibility to tune the velocity of the 23S positronium, excited following this scheme, is presented. In the light of these results, we discuss the use of the 33P→23S transition to realize a monochromatic pulsed 23S positronium beam with low angular divergence. Preliminary tests of 23S beam production are presented. The possibility to overcome the natural 33P→23S branching ratio via stimulated emission, and thus increasing the intensity of the 23S source, is also shown. A position-sensitive detector for a pulsed beam of positronium, with spatial resolution of ≈ 90 μm, is finally described in view of its possible application for the spatial characterization of the 23S beam

Evaluation of nickel-hydrogen battery for space application

Results of electrical space qualification tests of nickel-hydrogen battery type HR 23S are presented. The results obtained for the nickel-cadmium battery type VO 23S are similar except that the voltage level and the charge conservation characteristics vary significantly. The electrical and thermal characteristics permit predictions of the following optimal applications: charge coefficient in the order of 1.3 to 1.4 at 20C; charge current density higher than C/10 at 20C; discharge current density from C/10 to C/3 at 20C; maximum discharge temperature: OC; storage temperature: -20C

Diversity of 23S rRNA Genes within Individual Prokaryotic Genomes

The concept of ribosomal constraints on rRNA genes is deduced primarily based on the comparison of consensus rRNA sequences between closely related species, but recent advances in whole-genome sequencing allow evaluation of this concept within organisms with multiple rRNA operons. was the only species in which intragenomic diversity >3% was observed among 4 paralogous 23S rRNA genes.These findings indicate tight ribosomal constraints on individual 23S rRNA genes within a genome. Although classification using primary 23S rRNA sequences could be erroneous, significant diversity among paralogous 23S rRNA genes was observed only once in the 184 species analyzed, indicating little overall impact on the mainstream of 23S rRNA gene-based prokaryotic taxonomy

Recognition of Ribosomal RNA Sites in DNA, I. Analysis of the E. coli System

The evidence recently presented of specific hybridization between bacterial ribosomal RNA and homologous DNA1-3 has indicated the possibility of a biochemical approach to the problem of the identification of ribosomal RNA sites in DNA. A difficulty in this approach is that while the specific role of the RNA in the hybridization is open to experimental test, the critical evidence of the unique involvement of presumptive DNA sites is not easily attainable

Novel Ribosome Biogenesis in the Lyme Disease Spirochete Borrelia burgdorferi

Here we demonstrate the first characterization of an RNase III enzyme from a spirochete and its role in processing rRNA transcripts from the unusual rRNA gene operons of Borrelia burgdorferi. In most bacteria, the three rRNA transcripts (16S, 23S, and 5S rRNAs) that form the ribosome are produced as a single transcript from an operon with minimal spacing between genes. In the B. burgdorferi genome, however, a single 16S rRNA gene is encoded more than 3 kb from the bicistronic 23S-5S rRNA operons. The 23S-5S operons are tandemly duplicated, yielding an uneven number of rRNA genes, a feature unique to Lyme disease Borrelia. Additionally, the 16S and tandem 23S-5S operons appear to be synthesized as two separate transcripts. Our data show that B. burgdorferi RNase III processes the 3´ end of the 16S, 23S, but not the 5S, rRNA transcripts, as in other bacteria. However, 16S rRNA 5´ end processing proceeds by an as yet unidentified mechanism, which is an unprecedented finding. We hypothesize that this deviation from the canonical 16S rRNA processing pathway is likely an adaptation of B. burgdorferi to rRNA gene rearrangement during genome reduction and transition to a host-restricted lifestyle. In agreement with this finding, the 16S rRNA gene is transcribed as part of a larger operon containing unrelated genes, suggesting alternative regulation of the rRNA transcripts. Additionally, we show that the 23S rRNA is transcribed from identical promoters present in front of both tandem 23S rRNA genes and that this creates our observed 2.5 to 3-fold excess of 23S rRNA compared to 16S rRNA. Finally, single deletion mutants in each of the 23S rRNA genes were constructed. Surprisingly, deletion of the first 23S rRNA gene produces a severe growth phenotype and increased erythromycin susceptibility in vitro and a strain that is non-infectious in vivo. A mutant with a deletion in the second 23S rRNA gene shows no phenotype. The 23S rRNA genes have begun to acquire single nucleotide polymorphisms. However, their pattern currently indicates that they are the products of genetic drift. We conclude that the mechanism of rRNA transcription is unique in B. burgdorferi