Construction of the physical maps of Mycoplasma hyopneumoniae and Mycoplasma flocculare and the location of rRNA genes on these maps

1992 ◽  
Vol 38 (7) ◽  
pp. 659-663 ◽  
Author(s):  
Y. Huang ◽  
G. W. Stemke

The genomes of Mycoplasma flocculare and Mycoplasma hyopneumoniae, two mycoplasmas of the porcine respiratory system, were studied. Based upon antigenic cross-reactivity and DNA–DNA hybridization, these species have given indication of a close genetic relationship. By using field-inversion gel electrophoresis and employing the restriction digest fragments obtained from the gels as the probes, physical maps of the genomes of the two species were constructed. Mycoplasma hyopneumoniae is similar to M. flocculare in having a single set of rRNA genes and the 5S-rRNA gene is separated from the 16S and 23S rRNA genes. Based upon the location of the rRNA genes on the physical maps in both species, the distance between the 5S and the 16S and 23S rRNA genes is at least 150 kbp. Thus, there is further evidence for the close relationship between these organisms. Key words: Mycoplasma, Mollicutes, physical maps, rRNA.

2001 ◽  
Vol 183 (14) ◽  
pp. 4382-4385 ◽  
Author(s):  
Steven T. Gregory ◽  
Jamie H. D. Cate ◽  
Albert E. Dahlberg

ABSTRACT Spontaneous, erythromycin-resistant mutants of Thermus thermophilus IB-21 were isolated and found to carry the mutation A2058G in one of two 23S rRNA operons. The heterozygosity of these mutants indicates that A2058G confers a dominant or codominant phenotype in this organism. This mutation provides a valuable tool for the genetic manipulation of the 23S rRNA genes ofThermus.


1996 ◽  
Vol 47 (3) ◽  
pp. 387 ◽  
Author(s):  
B Liu ◽  
DT White ◽  
KB Walsh ◽  
PT Scott

Oligonucleotide primers complementary to regions specific to plant-pathogenic mycoplasma-like organisms (phytoplasmas) were used in polymerase chain reactions on tissue samples from dieback, yellow crinkle, and mosaic affected papaya plants. The primer pair P068/P069, which hybridise to internal regions of the 16s rRNA gene, amplified an approximately 560 bp product in dieback, yellow crinkle and mosaic affected papaya. The primer pair P3/P7, which hybridise to the spacer region between the 16s and 23s rRNA genes, amplified an approximately 300 bp fragment in yellow crinkle and mosaic affected papaya, with no product from dieback affected plants. No PCR product was obtained with either set of primers from healthy plants. An identical Alu I restriction enzyme profile was obtained with all three 560 bp products. This study provides the first evidence for the association of phytoplasmas with papaya mosaic and Australian papaya dieback.


2003 ◽  
Vol 47 (11) ◽  
pp. 3620-3622 ◽  
Author(s):  
Alistair Sinclair ◽  
Catherine Arnold ◽  
Neil Woodford

ABSTRACT Pyrosequencing was used to detect rapidly and estimate the number of 23S rRNA genes with a G2576T mutation in 43 linezolid-resistant and -susceptible clinical isolates of enterococci. The method showed 100% concordance with PCR-restriction fragment length polymorphism for detecting isolates homozygous for either G2576 or T2576 or heterozygous for this mutation. A good correlation was found between linezolid MICs and the number of 23S rRNA gene copies carrying the mutation.


2005 ◽  
Vol 187 (17) ◽  
pp. 6106-6118 ◽  
Author(s):  
Floyd E. Dewhirst ◽  
Zeli Shen ◽  
Michael S. Scimeca ◽  
Lauren N. Stokes ◽  
Tahani Boumenna ◽  
...  

ABSTRACT Analysis of 16S rRNA gene sequences has become the primary method for determining prokaryotic phylogeny. Phylogeny is currently the basis for prokaryotic systematics. Therefore, the validity of 16S rRNA gene-based phylogenetic analyses is of fundamental importance for prokaryotic systematics. Discrepancies between 16S rRNA gene analyses and DNA-DNA hybridization and phenotypic analyses have been noted in the genus Helicobacter. To clarify these discrepancies, we sequenced the 23S rRNA genes for 55 helicobacter strains representing 41 taxa (>2,700 bases per sequence). Phylogenetic-tree construction using neighbor-joining, parsimony, and maximum likelihood methods for 23S rRNA gene sequence data yielded stable trees which were consistent with other phenotypic and genotypic methods. The 16S rRNA gene sequence-derived trees were discordant with the 23S rRNA gene trees and other data. Discrepant 16S rRNA gene sequence data for the helicobacters are consistent with the horizontal transfer of 16S rRNA gene fragments and the creation of mosaic molecules with loss of phylogenetic information. These results suggest that taxonomic decisions must be supported by other phylogenetically informative macromolecules, such as the 23S rRNA gene, when 16S rRNA gene-derived phylogeny is discordant with other credible phenotypic and genotypic methods. This study found Wolinella succinogenes to branch with the unsheathed-flagellum cluster of helicobacters by 23S rRNA gene analyses and whole-genome comparisons. This study also found intervening sequences (IVSs) in the 23S rRNA genes of strains of 12 Helicobacter species. IVSs were found in helices 10, 25, and 45, as well as between helices 31′ and 27′. Simultaneous insertion of IVSs at three sites was found in H. mesocricetorum.


2010 ◽  
Vol 76 (10) ◽  
pp. 3071-3081 ◽  
Author(s):  
Si Ming Man ◽  
Nadeem O. Kaakoush ◽  
Sophie Octavia ◽  
Hazel Mitchell

ABSTRACT The Campylobacter genus consists of a number of important human and animal pathogens. Although the 16S rRNA gene has been used extensively for detection and identification of Campylobacter species, there is currently limited information on the 23S rRNA gene and the internal transcribed spacer (ITS) region that lies between the 16S and 23S rRNA genes. We examined the potential of the 23S rRNA gene and the ITS region to be used in species differentiation and delineation of systematic relationships for 30 taxa within the Campylobacter genus. The ITS region produced the highest mean pairwise percentage difference (35.94%) compared to the 16S (5.34%) and 23S (7.29%) rRNA genes. The discriminatory power for each region was further validated using Simpson's index of diversity (D value). The D values were 0.968, 0.995, and 0.766 for the ITS region and the 23S and 16S rRNA genes, respectively. A closer examination of the ITS region revealed that Campylobacter concisus, Campylobacter showae, and Campylobacter fetus subsp. fetus harbored tRNA configurations not previously reported for other members of the Campylobacter genus. We also observed the presence of strain-dependent intervening sequences in the 23S rRNA genes. Neighbor-joining trees using the ITS region revealed that Campylobacter jejuni and Campylobacter coli strains clustered in subgroups, which was not observed in trees derived from the 16S or 23S rRNA gene. Of the three regions examined, the ITS region is by far the most cost-effective region for the differentiation and delineation of systematic relationships within the Campylobacter genus.


1997 ◽  
Vol 41 (12) ◽  
pp. 2621-2628 ◽  
Author(s):  
D E Taylor ◽  
Z Ge ◽  
D Purych ◽  
T Lo ◽  
K Hiratsuka

In this study, two identical copies of a 23S-5S gene cluster, which are separately situated within the Helicobacter pylori UA802 chromosome, were cloned and sequenced. Comparison of the DNA sequence of the H. pylori 23S rRNA gene with known sequences of other bacterial 23S rRNA genes indicated that the H. pylori UA802 23S rRNA genes are closely related to those of Campylobacter spp. and therefore belong in the proposed Proteobacteria subdivision. The 5'-terminal nucleotide T or A of the 23S rRNA is close to a Pribnow box which could be a -10 region of the transcription promoter for the 23S rRNA gene, suggesting that a posttranscriptional process is likely not involved in the maturation of the H. pylori 23S rRNA. Clinical isolates of H. pylori resistant to clarithromycin were examined by using natural transformation and pulsed-field gel electrophoresis. Cross-resistance to clarithromycin and erythromycin, which was transferred by natural transformation from the Cla(r) Ery(r) donor strain H. pylori E to the Cla(s) Ery(s) recipient strain H. pylori UA802, was associated with an single A-to-G transition mutation at position 2142 of both copies of the 23S rRNA in UA802 Cla(r) Ery(r) mutants. The transformation frequency for Cla(r) and Ery(r) was found to be approximately 2 x 10(-6) transformants per viable cell, and the MICs of both clarithromycin and erythromycin for the Cla(r) Ery(r) mutants were equal to those for the donor isolate. Our results confirmed the previous findings that mutations at positions 2142 and 2143 of the H. pylori 23S rRNA gene are responsible for clarithromycin resistance and suggest that acquisition of clarithromycin resistance in H. pylori could also result from horizontal transfer.


2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Christophe Djemiel ◽  
Samuel Dequiedt ◽  
Battle Karimi ◽  
Aurélien Cottin ◽  
Thibault Girier ◽  
...  

Abstract Background The ability to compare samples or studies easily using metabarcoding so as to better interpret microbial ecology results is an upcoming challenge. A growing number of metabarcoding pipelines are available, each with its own benefits and limitations. However, very few have been developed to offer the opportunity to characterize various microbial communities (e.g., archaea, bacteria, fungi, photosynthetic microeukaryotes) with the same tool. Results BIOCOM-PIPE is a flexible and independent suite of tools for processing data from high-throughput sequencing technologies, Roche 454 and Illumina platforms, and focused on the diversity of archaeal, bacterial, fungal, and photosynthetic microeukaryote amplicons. Various original methods were implemented in BIOCOM-PIPE to (1) remove chimeras based on read abundance, (2) align sequences with structure-based alignments of RNA homologs using covariance models, and (3) a post-clustering tool (ReClustOR) to improve OTUs consistency based on a reference OTU database. The comparison with two other pipelines (FROGS and mothur) and Amplicon Sequence Variant definition highlighted that BIOCOM-PIPE was better at discriminating land use groups. Conclusions The BIOCOM-PIPE pipeline makes it possible to analyze 16S, 18S and 23S rRNA genes in the same packaged tool. The new post-clustering approach defines a biological database from previously analyzed samples and performs post-clustering of reads with this reference database by using open-reference clustering. This makes it easier to compare projects from various sequencing runs, and increased the congruence among results. For all users, the pipeline was developed to allow for adding or modifying the components, the databases and the bioinformatics tools easily, giving high modularity for each analysis.


1995 ◽  
Vol 41 (4-5) ◽  
pp. 424-427 ◽  
Author(s):  
Y. Huang ◽  
G. W. Stemke ◽  
J. A. Robertson

The macro-restriction map of Mycoplasma fermentans (incognitus strain) was constructed and its rRNA genes were located on the map. It was found that this organism contains two sets of rRNA genes. The 16S and 23S rRNA genes were closely linked as two clusters. However, both 5S rRNA genes were separated from the 16S and 23S genes. The two 16S–23S rRNA gene clusters were arranged in an unusual tail to tail orientation.Key words: physical map, rRNA, Mycoplasma fermentans, genome, gene organization.


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