Search results for "ribosomal DNA"
showing 10 items of 137 documents
16S rDNA analysis for characterization of denitrifying bacteria isolated from three agricultural soils
2000
Bacteria capable of denitrification are spread among phylogenetically diverse groups. In the present investigation, molecular methods (amplified ribosomal DNA restriction analysis (ARDRA) and partial 16S rDNA gene sequencing) were used to determine the genetic diversity of culturable denitrifying soil bacteria. The purpose of this work was to study the microbial density and diversity of denitrifying communities isolated from two luvisols and a rendosol. The denitrifying bacterial density was significantly higher in the two luvisols (3x10(6) and 4x10(6) bacteria g(-1) dry soil) than in the rendosol (4x10(5) bacteria g(-1) dry soil). Denitrifying isolates from soils were grouped according to …
Identification of a Unique Helicobacter Species by 16S rRNA Gene Analysis in an Abdominal Abscess from a Patient with X-Linked Hypogammaglobulinemia
2000
ABSTRACT A unique Helicobacter species, MZ640285, was isolated from a patient with X-linked hypogammaglobulinemia suffering from recurrent abdominal abscesses and was identified by 16S rRNA gene sequence analysis. In the phylogenetic tree, the isolate fell into a cluster which included Flexispira rappini , Helicobacter bilis , and Helicobacter sp. strain Mainz. Helicobacters are being increasingly recognized as pathogens in immunocompromised hosts. These fastidious bacteria are not easily cultured in the routine diagnostic laboratory, and this is the first report of their identification by 16S rRNA gene sequencing performed directly from a clinical specimen.
Helicobacter sp. strain Mainz isolated from an AIDS patient with septic arthritis: case report and nonradioactive analysis of 16S rRNA sequence
1994
A campylobacter-like organism was isolated from an effusion of the left knee joint of an AIDS patient 2 weeks after bacteremia with a morphologically identical organism. Amplified genomic 16S rRNA sequences were analyzed by a nonradioactive blotting technique. The closest match was found with Helicobacter fenelliae (97.7% homology). Sequence data and phenotype suggest that the isolate may represent a so far unrecognized species of the genus Helicobacter.
New insight into the systematic position of the endemic Madagascan genus Amberiana (Hemiptera: Heteroptera: Dinidoridae) using 12S rDNA sequences
2015
The systematic position of the endemic Madagascan genus Amberiana Dist. İs studied using DNA sequences (the mitochondrial 12S rDNA subunit) for the first time. The phylogenetic relationships within the superfamily Pentatomoidea were computed using neighbor-joining, maximum parsimony, minimum evolution, and maximum likelihood methods, as well as Bayesian estimation. All results based on the mtDNA analyses stand in contrast with previous morphological data. The mtDNA analysis showed close relationships of the genus Amberiana to the genus Sehirus (Cydnidae: Sehirinae) and to species of the family Parastrachiidae, whereas the morphology indicated that the genus was a typical representative of t…
Assessing genetic structure and diversity of airborne bacterial communities by DNA fingerprinting and 16S rDNA clone library
2005
Abstract The density, genetic structure and diversity of airborne bacterial communities were assessed in the outdoor atmosphere. Two air samples were collected on the same location (north of France) at two dates (March 2003 (sample1) and May 2003 (sample 2)). Molecular culture-independent methods were used to characterise airborne bacterial communities regardless of the cell culturability. The automated-ribosomal intergenic spacer analysis (A-RISA) was performed to characterise the community structure in each sample. For both sampling dates, complex A-RISA patterns were observed suggesting a highly diverse community structure, comparable to those found in soil, water or sediment environment…
B1 Was the Ancestor B Chromosome Variant in the Western Mediterranean Area in the Grasshopper Eyprepocnemis plorans.
2014
We analyzed the distribution of 2 repetitive DNAs, i.e. ribosomal DNA (rDNA) and a satellite DNA (satDNA), on the B chromosomes found in 17 natural populations of the grasshopper Eyprepocnemis plorans plorans sampled around the western Mediterranean region, including the Iberian Peninsula, Balearic Islands, Sicily, and Tunisia. Based on the amount of these repetitive DNAs, 4 types of B variants were found: B 1 , showing an equal or higher amount of rDNA than satDNA, and 3 other variants, B 2 , B 24 and B 5 , bearing a higher amount of satDNA than rDNA. The variants B 1 and B 2 varied in size among populations: B 1 was about half the size of the X chromosome in Balearic Islands, but two-thir…
Morphological and molecular taxonomy ofPythium longisporangiumsp. nov. isolated from the Burgundian region of France
2005
During the course of an investigation on the Pythiaceous oomycetes occurring in the Burgundian vineyards, some species of Pythium possessing mainly hypogynous antheridia were found. These had been classified as oomycetes belonging to the ‘‘Pythium rostratum’’ group for a long time. Three of these isolates, having similar structures and growth, are very closely related to a recently described species, Pythium bifurcatum Paul. A close look at these, however, underlines some fundamental differences with the latter. Not all of them produce zoospores but have very large sporangia. The type specimen is F-1200 (B 76a) which is a medium-slow growing saprophyte. The sequence of the ITS region of the…
Pythium prolatumisolated from soil in the Burgundy region: a new record for Europe
1999
Pythium prolatum Hendrix and Campbell has been isolated from a soil sample taken in the Burgundy region in France. The fungus is easily recognisable by its heavily ornamented oogonia with conical to mammiform spines, elongated sporangia, and its diclinous antheridia forming or originating from a tangled mass of hyphae. Descriptions of the morphological and reproductive aspects of Pythium prolatum, the polymerase chain reaction of the internal transcribed spacer (ITS1) of the ribosomal nuclear DNA as well as the nucleotide sequences of ITS1 coding for 5.8 S rRNA are given.
Pythium segnitiumsp. nov., isolated from the Canary Islands â its taxonomy, ITS region of rDNA, and comparison with related species
2002
Pythium segnitium (CI-44) was isolated from some soil samples taken in the Canary Islands (Spain). This new species is a slow-growing fungus and is perfectly adapted to terrestrial habitat. It belongs to the group of Pythium that have smooth-walled oogonia, mostly hypogynous antheridia, and plerotic oospores. The fungus lacks sporangia, zoospores, and hyphal bodies are rarely formed. Thus the asexual reproduction, which is so common for fungi and especially for the aquatic ones, is completely lacking in this case. However the fungus reproduces sexually by the formation of oogonia, antheridia and oospores plentifully. The taxonomic description of this fungus, the nucleotide sequence of the i…
SSU rDNA Characterization of Lymnaeid Snails Transmitting Human Fascioliasis in South and Central America
1997
The small subunit (18S) rRNA gene sequences of the lymnaeid morphs I and II (Mollusca: Gastropoda: Basommatophora: Lymnaeidae) transmitting human fascioliasis in the high endemic zone of the northern Bolivian Altiplano and of Lymnaea cubensis from Mexico and Guadeloupe island (Caribbean) have been obtained by direct polymerase chain reaction PCR cycle sequencing and silver staining methods and compared to that of the 6 most common European Lymnaeidae species. Results allow us to establish definitively the distinction between the lymnaeids from the northern Bolivian Altiplano and L. cubensis. Lymnaea cubensis is a valid species distributed in North and Central America but absent in the north…