scholarly journals Intragenomic and intraspecific heterogeneity in rrs may surpass interspecific variability in a natural population of Veillonella

Microbiology ◽  
2010 ◽  
Vol 156 (7) ◽  
pp. 2080-2091 ◽  
Author(s):  
Anne-Laure Michon ◽  
Fabien Aujoulat ◽  
Laurent Roudière ◽  
Olivier Soulier ◽  
Isabelle Zorgniotti ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Gene Diversity ◽  
Natural Populations ◽  
Variable Region ◽  
Housekeeping Gene ◽  
Single Copy ◽  
Population Based ◽  
Rrna Gene ◽  
Gene Copies

As well as intraspecific heterogeneity, intragenomic heterogeneity between 16S rRNA gene copies has been described for a range of bacteria. Due to the wide use of 16S rRNA gene sequence analysis for taxonomy, identification and metagenomics, evaluating the extent of these heterogeneities in natural populations is an essential prerequisite. We investigated inter- and intragenomic 16S rRNA gene heterogeneity of the variable region V3 in a population of 149 clinical isolates of Veillonella spp. of human origin and in 13 type or reference Veillonella strains using PCR-temporal temperature gel electrophoresis (TTGE). 16S rRNA gene diversity was high in the studied population, as 45 different banding patterns were observed. Intragenomic heterogeneity was demonstrated for 110 (74 %) isolates and 8 (61.5 %) type or reference strains displaying two or three different gene copies. Polymorphic nucleotide positions accounted for 0.5–2.5 % of the sequence and were scattered in helices H16 and H17 of the rRNA molecule. Some of them changed the secondary structure of H17. Phylotaxonomic structure of the population based on the single-copy housekeeping gene rpoB was compared with TTGE patterns. The intragenomic V3 heterogeneity, as well as recombination events between strains or isolates of different rpoB clades, impaired the 16S rRNA-based identification for some Veillonella species. Such approaches should be conducted in other bacterial populations to optimize the interpretation of 16S rRNA gene sequences in taxonomy and/or diversity studies.

scholarly journals Extremely Acidophilic Protists from Acid Mine Drainage Host Rickettsiales-Lineage Endosymbionts That Have Intervening Sequences in Their 16S rRNA Genes

2003 ◽  
Vol 69 (9) ◽  
pp. 5512-5518 ◽  
Author(s):  
Brett J. Baker ◽  
Philip Hugenholtz ◽  
Scott C. Dawson ◽  
Jillian F. Banfield
Keyword(s):  
Acid Mine Drainage ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Mine Drainage ◽  
Close Association ◽  
Variable Region ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Acid Mine

ABSTRACT During a molecular phylogenetic survey of extremely acidic (pH < 1), metal-rich acid mine drainage habitats in the Richmond Mine at Iron Mountain, Calif., we detected 16S rRNA gene sequences of a novel bacterial group belonging to the order Rickettsiales in the Alphaproteobacteria. The closest known relatives of this group (92% 16S rRNA gene sequence identity) are endosymbionts of the protist Acanthamoeba. Oligonucleotide 16S rRNA probes were designed and used to observe members of this group within acidophilic protists. To improve visualization of eukaryotic populations in the acid mine drainage samples, broad-specificity probes for eukaryotes were redesigned and combined to highlight this component of the acid mine drainage community. Approximately 4% of protists in the acid mine drainage samples contained endosymbionts. Measurements of internal pH of the protists showed that their cytosol is close to neutral, indicating that the endosymbionts may be neutrophilic. The endosymbionts had a conserved 273-nucleotide intervening sequence (IVS) in variable region V1 of their 16S rRNA genes. The IVS does not match any sequence in current databases, but the predicted secondary structure forms well-defined stem loops. IVSs are uncommon in rRNA genes and appear to be confined to bacteria living in close association with eukaryotes. Based on the phylogenetic novelty of the endosymbiont sequences and initial culture-independent characterization, we propose the name “Candidatus Captivus acidiprotistae.” To our knowledge, this is the first report of an endosymbiotic relationship in an extremely acidic habitat.

scholarly journals Six species of nontuberculous mycobacteria carry non-identical 16S rRNA gene copies

2018 ◽  
Vol 155 ◽  
pp. 34-36
Author(s):  
Keita Takeda ◽  
Kinuyo Chikamatsu ◽  
Yuriko Igarashi ◽  
Yuta Morishige ◽  
Yoshiro Murase ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Nontuberculous Mycobacteria ◽  
Rrna Gene ◽  
Gene Copies

Heterogeneity between 16S ribosomal RNA gene copies borne by one Desulfitobacterium strain is caused by different 100-200 bp insertions in the 5´ region

2007 ◽  
Vol 53 (1) ◽  
pp. 116-128 ◽  
Author(s):  
Richard Villemur ◽  
Philippe Constant ◽  
Annie Gauthier ◽  
Martine Shareck ◽  
Réjean Beaudet
Keyword(s):  
In Situ Hybridization ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Ribosomal Rna ◽  
16S Ribosomal Rna ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Gene Copies

Strains of Desulfitobacterium hafniense, such as strains PCP-1, DP7, TCE1, and TCP-A, have unusual long 16S ribosomal RNA (rRNA) genes due to an insertion of approximately 100 bp in the 5' region. In this report, we analyzed the 16S rRNA genes of different Desulfitobacterium strains to determine if such an insertion is a common feature of desulfitobacteria. We amplified this region by polymerase chain reaction (PCR) from eight Desulfitobacterium strains (D. hafniense strains PCP-1, DP7, TCP-A, TCE1, and DCB-2; D. dehalogenans; D. chlororespirans; and Desulfitobacterium sp. PCE1) and resolved each PCR product by denaturing gradient gel electrophoresis (DGGE). All strains had from two to seven DGGE- migrating bands, suggesting heterogeneity in their 16S rRNA gene copies. For each strain, the 5' region of the 16S rRNA genes was amplified and a clone library was derived. Clones corresponding to most PCR–DGGE migration bands were isolated. Sequencing of representative clones revealed that the heterogeneity was generated by insertions of 100–200 bp. An insertion was found in at least one copy of the 16S rRNA gene in all examined strains. In total, we found eight different types of insertions (INS1–INS8) that varied from 123 to 193 nt in length. Two-dimensional structural analyses of transcribed sequences predicted that all insertions would form an energetically stable loop. Reverse transcriptase – PCR experiments revealed that most of the observed insertions in the Desulfitobacterium strains were excised from the mature 16S rRNA transcripts. Insertions were not commonly found in bacterial 16S rRNA genes, and having a different insertion in several 16S rRNA gene copies borne by a single bacterial species was rarely observed. The function of these insertions is not known, but their occurrence can have an important impact in deriving 16S rRNA oligonucleotidic fluorescence in situ hybridization probes, as these insertions can be excised from 16S rRNA transcripts.Key words: Desulfitobacterium, 16S ribosomal RNA genes, heterogeneity, gene insertions, fluorescence in situ hybridization.

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.

scholarly journals Direct Quantification of Campylobacter jejuni and Campylobacter lanienae in Feces of Cattle by Real-Time Quantitative PCR

2004 ◽  
Vol 70 (4) ◽  
pp. 2296-2306 ◽  
Author(s):  
G. Douglas Inglis ◽  
Lisa D. Kalischuk
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Real Time ◽  
Campylobacter Jejuni ◽  
Single Copy ◽  
Mitigation Strategies ◽  
Rrna Gene ◽  
Limit Of Quantification ◽  
Cattle Feces ◽  
The Impact

ABSTRACT Campylobacter species are fastidious to culture, and the ability to directly quantify biomass in microbiologically complex substrates using real-time quantitative (RTQ) PCR may enhance our understanding of their biology and facilitate the development of efficacious mitigation strategies. This study reports the use of nested RTQ-PCR to directly quantify Campylobacter jejuni and Campylobacter lanienae in cattle feces. For C. jejuni, the single-copy mapA gene was selected. For C. lanienae, the three-copy 16S rRNA gene was targeted. RTQ-PCR primers were tested alone or they were nested with species-specific primers, and amplification products were detected using the intercalating dye SYBR Green. Nesting did not increase the specificity or sensitivity of C. jejuni quantification, and the limit of quantification was 19 to 25 genome copies (≈3 × 103 CFU/g of feces). In contrast, nested RTQ-PCR was necessary to confer specificity on C. lanienae by targeting the 16S rRNA gene. The limit of quantification was 1.8 genome copies (≈250 CFU/g of feces), and there was no discernible difference between the two C. lanienae secondary primer sets evaluated. Detection and quantification of C. jejuni in naturally infested cattle feces by RTQ-PCR were comparable to the results of culture-based methods. In contrast, culturing did not detect C. lanienae in 6 of 10 fecal samples positive for the bacterium and substantially underestimated cell densities relative to nested RTQ-PCR. The results of this study illustrate that RTQ-PCR can be used to directly quantify campylobacters, including very fastidious species, in a microbiologically and chemically complex substrate. Furthermore, targeting of a multicopy universal gene provided highly sensitive quantification of C. lanienae, but nested RTQ-PCR was necessary to confer specificity. This method will facilitate subsequent studies to elucidate the impact of this group of bacteria within the gastrointestinal tracts of livestock and studies of the factors that influence colonization success and shedding.

High bacterial 16S rRNA gene diversity above the atmospheric boundary layer

Aerobiologia ◽  
2012 ◽  
Vol 28 (4) ◽  
pp. 481-498 ◽  
Author(s):  
Ulla Li Zweifel ◽  
Åke Hagström ◽  
Karin Holmfeldt ◽  
Runar Thyrhaug ◽  
Camilla Geels ◽  
...  
Keyword(s):  
Boundary Layer ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Atmospheric Boundary Layer ◽  
Gene Diversity ◽  
Rrna Gene ◽  
Bacterial 16S Rrna Gene

scholarly journals Bacterial DNAemia is associated with serum zonulin levels in older subjects

2020 ◽  
Author(s):  
Giorgio Gargari ◽  
Valentina Taverniti ◽  
Cristian Del Bo’ ◽  
Stefano Bernardi ◽  
Cristina Andres-Lacueva ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Serum Levels ◽  
Gene Profiling ◽  
Rrna Gene ◽  
Bacterial Dna ◽  
Blood Samples ◽  
Gene Copies ◽  
Older Subjects ◽  
Pcr Targeting

AbstractThe increased presence of bacteria in blood is a plausible contributing factor in the development and progression of aging-associated diseases. In this context, we performed the quantification and the taxonomic profiling of the bacterial DNA in blood samples collected from a group of forty-three older subjects enrolled in a nursing home. Quantitative PCR targeting the 16S rRNA gene revealed that all the older volunteers contained detectable amounts of bacterial DNA in their blood. The total amount of 16S rRNA gene copies varied considerably between subjects. Correlation analyses revealed that the bacterial DNAemia (expressed as concentration of 16S rRNA gene copies in blood) significantly correlated with the serum levels of zonulin, an emerging marker of intestinal permeability. This result was confirmed by the analysis of a second set of blood samples collected after approximately four months from the same subjects. Analyses of 16S rRNA gene profiling revealed that most of the bacterial DNA detected in blood was ascribable to the phylum Proteobacteria with a predominance of Pseudomonadaceae and Enterobacteriaceae. Several control samples were also analyzed to assess the influence exerted by contaminant bacterial DNA potentially originating from reagents and materials. The date reported here suggest that para-cellular permeability of epithelial (and potentially also endothelial) cell layers may play an important role in bacterial migration into the bloodstream. Bacterial DNAemia is likely to impact on several aspects of host physiology and could underpin the development and prognosis of various diseases in older subjects.

scholarly journals Six species of non-tuberculosis mycobacteria carry non-identical 16S rRNA gene copies

2018 ◽  
Author(s):  
Keita Takeda ◽  
Kinuyo Chikamatsu ◽  
Yuriko Igarashi ◽  
Yuta Morishige ◽  
Yoshiro Murase ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Rrna Gene ◽  
Target Sequence ◽  
Nucleotide Polymorphisms ◽  
16S Rrna Gene Sequences ◽  
Cloning And Sequencing ◽  
Single Nucleotide ◽  
Gene Copies ◽  
The 16S Rrna Gene

AbstractNon-tuberculosis mycobacteria (NTM) can carry two or more 16S rRNA gene copies that are, in some instances, non-identical. In this study, we used a combined cloning and sequencing approach to analyze the 16S rRNA gene sequences of six NTM species,Mycobacterium cosmeticum, M. pallens, M. hodleri, M. crocinum, M. flavescens, andM. xenopi. The approach facilitated the identification of two distinct gene copies in each species. The twoM. cosmeticumgenes had a single nucleotide difference, whereas two nucleotide polymorphisms were identified inM. hodleri, M. flavescens, andM. xenopi. M. pallenshad a difference in four nucleotides andM. crocinumin 23. Hence, we showed that the six NTM species possess at least two non-identical 16S rRNA gene copies.ImportanceThe presence of multiple 16S rRNA gene copies with nucleotide polymorphisms represents a challenge for species identification using 16S rRNA as the target sequence. Our analysis was focused on six NTM species,M. cosmeticum, M. pallens, M. hodleri, M. crocinum, M. flavescens, andM. xenopi. As a result, we generated the full-length sequences of two non-identical 16S rRNA copies for each NTM species. The data will be helpful for the sequence analysis of specimens or other samples.

Sign in / Sign up

Export Citation Format

Share Document