The structure and organization of the 16S ribosomal RNA gene from the archaebacterium Thermoplasma acidophilum

1989 ◽  
Vol 35 (1) ◽  
pp. 124-133 ◽  
Author(s):  
Heesoo K. Ree ◽  
Kaiming Cao ◽  
David L. Thurlow ◽  
Robert A. Zimmermann
Keyword(s):  
Secondary Structure ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Transcription Initiation ◽  
Single Copy ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Transcription Control ◽  
Thermoplasma Acidophilum ◽  
The 16S Rrna Gene

The complete nucleotide sequence of the 16S rRNA gene from Thermoplasma acidophilum, as well as its 5′ and 3′ flanking regions, were determined by the dideoxynucleotide chain termination method. The 16S rRNA gene encodes 1471 nucleotides. The primary and secondary structures of T. acidophilum 16S rRNA both exhibit typical archaebacterial features. The sequence appears to be more closely related to 16S rRNAs of the methanogen–halophile group than to those of the thermoacidophile group. Secondary-structure comparisons generally support this relationship, although there are several examples in which the single-stranded loops in particular helices of T. acidophilum 16S rRNA more strongly resemble their counterparts in the 16S rRNA of Sulfolobus solfataricus, a member of the thermoacidophile group. In contrast to the polycistronic rRNA operons found in most organisms, the three rRNA genes from T. acidophilum occur in only a single copy per genome and appear to be physically unlinked. Consistent with this, the 16S rRNA gene is flanked by putative promoter and terminator sequences that are comparable to the transcription control signals from other archaebacterial genes. The sequence TATATATA, which is very similar to the archaebacterial promoter consensus TTTAT/AATA, is located 18 bases before the probable site of transcription initiation, TGCACAT. There is a potential transcription termination site immediately downstream from the gene that consists of a relatively stable stem and loop structure followed by stretches of Tresidues.Key words: archaebacteria, thermoacidophile, rRNA sequence, rRNA secondary structure, promoter.

Clover proliferation phytoplasma: ‘Candidatus Phytoplasma trifolii’

2004 ◽  
Vol 54 (4) ◽  
pp. 1349-1353 ◽  
Author(s):  
Chuji Hiruki ◽  
Keri Wang
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Reference Strain ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Beet Leafhopper ◽  
Signature Sequences ◽  
Elm Yellows ◽  
The 16S Rrna Gene

Clover proliferation phytoplasma (CPR) is designated as the reference strain for the CP phylogenetic group or subclade, on the basis of molecular analyses of genomic DNA, the 16S rRNA gene and the 16S–23S spacer region. Other strains related to CPR include alfalfa witches'-broom (AWB), brinjal little leaf (BLL), beet leafhopper-transmitted virescence (BLTV), Illinois elm yellows (ILEY), potato witches'-broom (PWB), potato yellows (PY), tomato big bud in California (TBBc) and phytoplasmas from Fragaria multicipita (FM). Phylogenetic analysis of the 16S rRNA gene sequences of BLL, CPR, FM and ILEY, together with sequences from 16 other phytoplasmas that belong to the ash yellows (AshY), jujube witches'-broom (JWB) and elm yellows (EY) groups that were available in GenBank, produced a tree on which these phytoplasmas clearly clustered as a discrete group. Three subgroups have been classified on the basis of sequence homology and the collective RFLP patterns of amplified 16S rRNA genes. AWB, BLTV, PWB and TBBc are assigned to taxonomic subgroup CP-A, FM belongs to subgroup CP-B and BLL and ILEY are assigned to subgroup CP-C. Genetic heterogeneity between different isolates of AWB, CPR and PWB has been observed from heteroduplex mobility assay analysis of amplified 16S rRNA genes and the 16S–23S spacer region. Two unique signature sequences that can be utilized to distinguish the CP group from others were present. On the basis of unique properties of the DNA from clover proliferation phytoplasma, the name ‘Candidatus Phytoplasma trifolii’ is proposed for the CP group.

Overestimation of Streptococcus mutans prevalence by nested PCR detection of the 16S rRNA gene

2006 ◽  
Vol 55 (1) ◽  
pp. 109-113 ◽  
Author(s):  
Ali Al-Ahmad ◽  
Thorsten Mathias Auschill ◽  
Gabriele Braun ◽  
Elmar Hellwig ◽  
Nicole Birgit Arweiler
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Streptococcus Mutans ◽  
Nested Pcr ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Direct Pcr ◽  
Specific Primers ◽  
The 16S Rrna Gene

This study was carried out in order to compare two PCR-based methods in the detection of Streptococcus mutans. The first PCR method was based on primers for the 16S rRNA gene and the second method was based on specific primers that targeted the glucosyltransferase gene (gtfB). Each PCR was performed with eight different streptococci from the viridans group, five other streptococci and 17 different non-streptococcal bacterial strains. Direct use of the S. mutans 16S rRNA gene-specific primers revealed that Streptococcus gordonii and Streptococcus infantis were also detected. After amplifying the 16S rRNA gene with universal primers and subsequently performing nested PCR, the S. mutans-specific nested primers based on the 16S rRNA gene detected all tested streptococci. There was no cross-reaction of the gtfB primers after direct PCR. Our results indicate that direct PCR and nested PCR based on 16S rRNA genes can reveal false-positive results for oral streptococci and lead to an overestimation of the prevalence of S. mutans with regards to its role as the most prevalent causative agent of dental caries.

scholarly journals Identification of Mycobacterium kansasiiby Using a DNA Probe (AccuProbe) and Molecular Techniques

1999 ◽  
Vol 37 (4) ◽  
pp. 964-970 ◽  
Author(s):  
Elvira Richter ◽  
Stefan Niemann ◽  
Sabine Rüsch-Gerdes ◽  
Sven Hoffner
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Restriction Pattern ◽  
Molecular Techniques ◽  
Rrna Genes ◽  
23S Rrna ◽  
Rrna Gene ◽  
Genetic Analyses ◽  
New Formulation ◽  
The 16S Rrna Gene

The newly formulated Mycobacterium kansasii AccuProbe was evaluated, and the results obtained with the new version were compared to the results obtained with the old version of this test by using 116 M. kansasii strains, 1 Mycobacterium gastri strain, and 19 strains of several mycobacterial species. The sensitivity of this new formulation was 97.4% and the specificity was 100%. Still, three M. kansasii strains were missed by this probe. To evaluate the variability within the species, genetic analyses of the hsp65 gene, the spacer sequence between the 16S and 23S rRNA genes, and the 16S rRNA gene of several M. kansasii AccuProbe-positive strains as well as all AccuProbe-negative strains were performed. Genetic analyses of the oneM. gastri strain from the comparative assay and of two further M. gastri strains were included because of the identity of the 16S rRNA gene in M. gastri to that inM. kansasii. The data confirmed the genetic heterogeneity of M. kansasii. Furthermore, a subspecies with an unpublished hsp65 restriction pattern and spacer sequence was described. The genetic data indicate that all M. kansasii strains missed by the AccuProbe test belong to one subspecies, the newly described subspecies VI, as determined by thehsp65 restriction pattern and the spacer sequence. Since the M. kansasii strains that are missed are rare and allM. gastri strains are correctly negative, the new formulated AccuProbe provides a useful tool for the identification ofM. kansasii.

scholarly journals Reassessment of the phylogenetic relationships of Thiomonas cuprina

2007 ◽  
Vol 57 (11) ◽  
pp. 2720-2724 ◽  
Author(s):  
Donovan P. Kelly ◽  
Yoshihito Uchino ◽  
Harald Huber ◽  
Ricardo Amils ◽  
Ann P. Wood
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Gene Sequence ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
23S Rrna ◽  
Rrna Gene ◽  
Significant Similarity ◽  
23S Rrna Gene ◽  
The 16S Rrna Gene

The published sequence of the 16S rRNA gene of Thiomonas cuprina strain Hö5 (=DSM 5495T) (GenBank accession no. U67162) was found to be erroneous. The 16S rRNA genes from the type strain held by the DSMZ since 1990 (DSM 5495T =NBRC 102145T) and strain Hö5 maintained frozen in the Universität Regensburg for 23 years (=NBRC 102094) were sequenced and found to be identical, but to show no significant similarity to the U67162 sequence. This also casts some doubt on the previously published 5S and 23S rRNA gene sequences (GenBank accession nos U67171 and X75567). The correct 16S rRNA gene sequence showed 99.8 % identity to those from Thiomonas delicata NBRC 14566T and ‘Thiomonas arsenivorans’ DSM 16361. The properties of these three species are re-evaluated, and emended descriptions are provided for the genus Thiomonas and the species Thiomonas cuprina.

scholarly journals Horizontal Transfer of Segments of the 16S rRNA Genesbetween Species of the Streptococcus anginosusGroup

2003 ◽  
Vol 185 (24) ◽  
pp. 7241-7246 ◽  
Author(s):  
Leo M. Schouls ◽  
Corrie S. Schot ◽  
Jan A. Jacobs
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Horizontal Transfer ◽  
Blot Hybridization ◽  
Reverse Line Blot ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Streptococcus Anginosus ◽  
The 16S Rrna Gene

ABSTRACT The nature in variation of the 16S rRNA gene of members of the Streptococcus anginosus group was investigated by hybridization and DNA sequencing. A collection of 708 strains was analyzed by reverse line blot hybridization. This revealed the presence of distinct reaction patterns representing 11 different hybridization groups. The 16S rRNA genes of two strains of each hybridization group were sequenced to near-completion, and the sequence data confirmed the reverse line blot hybridization results. Closer inspection of the sequences revealed mosaic-like structures, strongly suggesting horizontal transfer of segments of the 16S rRNA gene between different species belonging to the Streptococcus anginosus group. Southern blot hybridization further showed that within a single strain all copies of the 16S rRNA gene had the same composition, indicating that the apparent mosaic structures were not PCR-induced artifacts. These findings indicate that the highly conserved rRNA genes are also subject to recombination and that these events may be fixed in the population. Such recombination may lead to the construction of incorrect phylogenetic trees based on the 16S rRNA genes.

scholarly journals Comparative Genetic Diversity of the narG, nosZ, and 16S rRNA Genes in Fluorescent Pseudomonads

2003 ◽  
Vol 69 (2) ◽  
pp. 1004-1012 ◽  
Author(s):  
Sandrine Delorme ◽  
Laurent Philippot ◽  
Veronique Edel-Hermann ◽  
Chrystel Deulvot ◽  
Christophe Mougel ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Pairwise Comparison ◽  
Fluorescent Pseudomonads ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Bacterial Strains ◽  
Good Correspondence ◽  
The 16S Rrna Gene

ABSTRACT The diversity of the membrane-bound nitrate reductase (narG) and nitrous oxide reductase (nosZ) genes in fluorescent pseudomonads isolated from soil and rhizosphere environments was characterized together with that of the 16S rRNA gene by a PCR-restriction fragment length polymorphism assay. Fragments of 1,008 bp and 1,433 bp were amplified via PCR with primers specific for the narG and nosZ genes, respectively. The presence of the narG and nosZ genes in the bacterial strains was confirmed by hybridization of the genomic DNA and the PCR products with the corresponding probes. The ability of the strains to either reduce nitrate or totally dissimilate nitrogen was assessed. Overall, there was a good correspondence between the reductase activities and the presence of the corresponding genes. Distribution in the different ribotypes of strains harboring both the narG and nosZ genes and of strains missing both genes suggests that these two groups of strains had different evolutionary histories. Both dissimilatory genes showed high polymorphism, with similarity indexes (Jaccard) of between 0.04 and 0.8, whereas those of the 16S rRNA gene only varied from 0.77 to 0.99. No correlation between the similarity indexes of 16S rRNA and dissimilatory genes was seen, suggesting that the evolution rates of ribosomal and functional genes differ. Pairwise comparison of similarity indexes of the narG and nosZ genes led to the delineation of two types of strains. Within the first type, the similarity indexes of both genes varied in the same range, suggesting that these two genes have followed a similar evolution. Within the second type of strain, the range of variations was higher for the nosZ than for the narG gene, suggesting that these genes have had a different evolutionary rate.

scholarly journals Towards a Genome-Based Taxonomy for Prokaryotes

2005 ◽  
Vol 187 (18) ◽  
pp. 6258-6264 ◽  
Author(s):  
Konstantinos T. Konstantinidis ◽  
James M. Tiedje
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Gene Content ◽  
Rrna Genes ◽  
23S Rrna ◽  
Rrna Gene ◽  
Protein Coding ◽  
Protein Coding Genes ◽  
A Genome ◽  
The 16S Rrna Gene

ABSTRACT The ranks higher than the species in the prokaryotic taxonomy are primarily designated based on phylogenetic analysis of the 16S rRNA gene sequences, but no definite standards exist for the absolute relatedness (measured by 16S rRNA or other means) between the ranks. Accordingly, it remains unknown how comparable the ranks are between different organisms. To gain insights into this question, we studied the relationship between shared gene content and genetic relatedness for 175 fully sequenced strains, using as a robust measure of relatedness the average amino acid identity (AAI) of the shared genes. Our results reveal that adjacent ranks (e.g., phylum versus class) frequently show extensive overlap in terms of genetic and gene content relatedness of the grouped organisms, and hence, the current system is of limited predictive power in this respect. The overlap between nonadjacent ranks (e.g., phylum versus family) is generally limited and attributable to clear inconsistencies of the taxonomy. In addition to providing means for standardizing taxonomy, our AAI-based approach provides a means to evaluate the robustness of alternative genetic markers for phylogenetic purposes. For instance, the 23S rRNA gene was found to be as good a marker as the 16S rRNA gene, while several of the widely distributed protein-coding genes, such as the RNA polymerase and gyrase subunits, show a strong phylogenetic signal, albeit less strong than the rRNA genes (0.78 > R 2 > 0.69 for the protein-coding genes versus R 2 = 0.84 for the rRNA genes). The AAI approach outlined here could contribute significantly to a genome-based taxonomy for all microbial organisms.

scholarly journals Mutations in the 16S rRNA Genes of Helicobacter pylori Mediate Resistance to Tetracycline

2002 ◽  
Vol 184 (8) ◽  
pp. 2131-2140 ◽  
Author(s):  
Catharine A. Trieber ◽  
Diane E. Taylor
Keyword(s):  
Helicobacter Pylori ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Tetracycline Resistance ◽  
Clinical Isolates ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Nucleotide Substitutions ◽  
The 16S Rrna Gene

ABSTRACT Low-cost and rescue treatments for Helicobacter pylori infections involve combinations of several drugs including tetracycline. Resistance to tetracycline has recently emerged in H. pylori. The 16S rRNA gene sequences of two tetracycline-resistant clinical isolates (MIC = 64 μg/ml) were determined and compared to the consensus H. pylori 16S rRNA sequence. One isolate had four nucleotide substitutions, and the other had four substitutions and two deletions. Natural transformation with the 16S rRNA genes from the resistant organisms conferred tetracycline resistance on susceptible strains. 16S rRNA genes containing the individual mutations were constructed and tested for the ability to confer resistance. Only the 16S rRNA gene containing the triple mutation, AGA965-967TTC, was able to confer tetracycline resistance on H. pylori 26695. The MICs of tetracycline for the transformed strains were equivalent to those for the original clinical isolates. The two original isolates were also metronidazole resistant, but this trait was not linked to the tetracycline resistance phenotype. Serial passage of several H. pylori strains on increasing concentrations of tetracycline yielded mutants with only a very modest increase in tetracycline resistance to a MIC of 4 to 8 μg/ml. These mutants all had a deletion of G942 in the 16S rRNA genes. The mutations in the 16S rRNA are clearly responsible for tetracycline resistance in H. pylori.

scholarly journals Pyrosequencing ofmcrAand Archaeal 16S rRNA Genes Reveals Diversity and Substrate Preferences of Methanogen Communities in Anaerobic Digesters

2014 ◽  
Vol 81 (2) ◽  
pp. 604-613 ◽  
Author(s):  
David Wilkins ◽  
Xiao-Ying Lu ◽  
Zhiyong Shen ◽  
Jiapeng Chen ◽  
Patrick K. H. Lee
Keyword(s):  
Anaerobic Digestion ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Methanogenic Archaea ◽  
16S Rrna Gene Sequencing ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Content Type ◽  
The 16S Rrna Gene

ABSTRACTMethanogenic archaea play a key role in biogas-producing anaerobic digestion and yet remain poorly taxonomically characterized. This is in part due to the limitations of low-throughput Sanger sequencing of a single (16S rRNA) gene, which in the past may have undersampled methanogen diversity. In this study, archaeal communities from three sludge digesters in Hong Kong and one wastewater digester in China were examined using high-throughput pyrosequencing of the methyl coenzyme M reductase (mcrA) and 16S rRNA genes.Methanobacteriales,Methanomicrobiales, andMethanosarcinaleswere detected in each digester, indicating that both hydrogenotrophic and acetoclastic methanogenesis was occurring. Two sludge digesters had similar community structures, likely due to their similar design and feedstock. Taxonomic classification of themcrAgenes suggested that these digesters were dominated by acetoclastic methanogens, particularlyMethanosarcinales, while the other digesters were dominated by hydrogenotrophicMethanomicrobiales. The proposed euryarchaeotal orderMethanomassiliicoccalesand the uncultured WSA2 group were detected with the 16S rRNA gene, and potentialmcrAgenes for these groups were identified. 16S rRNA gene sequencing also recovered several crenarchaeotal groups potentially involved in the initial anaerobic digestion processes. Overall, the two genes produced different taxonomic profiles for the digesters, while greater methanogen richness was detected using themcrAgene, supporting the use of this functional gene as a complement to the 16S rRNA gene to better assess methanogen diversity. A significant positive correlation was detected between methane production and the abundance ofmcrAtranscripts in digesters treating sludge and wastewater samples, supporting themcrAgene as a biomarker for methane yield.

scholarly journals Taxonomic note: speciation within the operational group Bacillus amyloliquefaciens based on comparative phylogenies of housekeeping genes

2020 ◽  
pp. 19-26
Author(s):  
Mohamad Syazwan Ngalimat ◽  
Suriana Sabri
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Phylogenetic Analyses ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Ratio Test ◽  
Group B ◽  
The 16S Rrna Gene ◽  
Operational Group

Many of the publically available Bacillus 16S rRNA genes and genomes in the NCBI database are inconsistently assigned as B. amyloliquefaciens. The highly conserved nature of the 16S rRNA gene makes it fail to differentiate species within the operational group B. amyloliquefaciens. Here, comparative phylogenies of the complete 16S rRNA, gyrB, rpoB, trpB, recA, and cheA nucleotide sequences of bacterial strains within the operational group were analyzed. As the result, the gyrB, rpoB, and trpB phylogenetic analyses showed stable topology that comprised three monophyletic clades: (i) B. amyloliquefaciens; (ii) B. siamensis; and (iii) B. velezensis. Phylogenies derived by comparison of the gyrB, rpoB, trpB, recA, and cheA with the 16S rRNA gene-derived phylogeny was significant as evaluated by the likelihood ratio test. The trpB, rpoB, and trpB gene-derived phylogenies provide a tool for speciation within the operational group B. amyloliquefaciens.

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