Search results for "PHYLOGENY"
showing 10 items of 1398 documents
Characterization of Gibberella fujikuroi complex isolates by fumonisin B-1 and B-2 analysis and by RAPD and restriction analysis of PCR-amplified int…
2000
Summary Twenty nine isolates of Fusarium spp. (twenty four of them belonging to the Gibberella fujikuroi complex) isolated from banana and corn from different geographical regions were analyzed for their ability to produce fumonisins B 1 and B 2 and for genetic relatedness using random amplified polymorphic DNA (RAPD) and restriction analysis of PCR amplification products of the 5.8s ribosomal DNA-intervening internal transcribed spacer regions (ITS I-5.8S-ITS II). For RAPD analysis, six of twenty oligonucleotide primers were selected after testing with five Fusarium spp. isolates and used to characterize 24 additional isolates. DNA fragments from the 29 isolates of Fusarium spp., which wer…
Ancient human DNA.
2011
The contribution of palaeogenetic data to the study of various aspects of hominin biology and evolution has been significant, and has the potential to increase substantially with the widespread implementation of next generation sequencing techniques. Here we discuss the present state-of-the-art of ancient human DNA analysis and the characteristics of hominin aDNA that make sequence validation particularly complex. A brief overview of the development of anthropological palaeogenetic analysis is given to illustrate the technical challenges motivating recent technological advancements.
Isolation and characterisation of Nocardioides sp. SP12, an atrazine-degrading bacterial strain possessing the gene trzN from bulk- and maize rhizosp…
2003
International audience; We report the characterisation of Nocardioides sp. SP12, an atrazine-degrading bacteria isolated from atrazine-treated bulk- and maize rhizosphere soil. Based on 16S rDNA alignment, strain SP12 showed close phylogenic relationships with Nocardioides sp. C157 and Nocardioides simplex. Internal transcribed spacer (ITS) sequences of strain SP12 were longer than those of other Nocardioides sp. and present Ala- and Ile-tRNA unlike Actinomycetales. Nocardioides sp. SP12 presents a novel atrazine catabolic pathway combining trzN with atzB and atzC. Atrazine biodegradation ends in a metabolite that co-eluted in HPLC with cyanuric acid. This metabolite shows an absorption spe…
Pythium burgundicum sp. nov. isolated from soil samples taken in French vineyards.
2009
During the course of investigation on pythiaceous fungi occurring in the Burgundian vineyards, a new species of Pythium has been isolated. This oomycete is characterized by its nonproliferating and nonsporulating, spherical to cylindrical type of sporangia (hyphal bodies) germinating through germ tubes, smooth-walled oogonia that are supplied with hypogynous, monoclinous or rarely diclinous antheridia, and smooth-walled oospores. The antheridial cells are very prominent and are reminiscent of Pythium bifurcatum, Pythium segnitium and Pythium longandrum described previously by the author. The internal transcribed spacer region of the rRNA of this new species is composed of 883 bases, which i…
On the Age of Leprosy
2014
Leprosy is a chronic infection of the skin and nerves caused by Mycobacterium leprae and the newly discovered Mycobacterium lepromatosis. Human leprosy has been documented for millennia in ancient cultures. Recent genomic studies of worldwide M. leprae strains have further traced it along global human dispersals during the past ∼ 100,000 years. Because leprosy bacilli are strictly intracellular, we wonder how long humans have been affected by this disease-causing parasite. Based on recently published data on M. leprae genomes, M. lepromatosis discovery, leprosy bacilli evolution, and human evolution, it is most likely that the leprosy bacilli started parasitic evolution in humans or early h…
Polymorphism of mytilin B mRNA is not traslated into mature peptide
2008
Diversity of mRNAs from mytilin B, one of the five mytilins identified in the Mediterranean mussel, Mytilus galloprovincialis, has been investigated from circulating hemocytes. One mussel expressed simultaneously two to ten different mytilin B mRNAs as observed in denaturing gradient gel electrophoresis (DGGE), defining 10 individual DGGE patterns (named A to J) within the mussels from Messina, Sicily (Italy). Three patterns accounted for 79% of the individuals whereas other patterns were found in only 2-7% of the 57 analyzed mussels. Base mutations were observed at specific locations, mainly within COOH-terminus and 3'UTR, leading to 36 nucleotide sequence variants and 21 different coding …
Isolation of Desulfovibrio intestinalis sp. nov. from the hindgut' of the lower termite Mastotermes darwiniensis.
1999
A Gram-negative, anaerobic sulfate-reducing bacterium was isolated from hindgut contents of the lower termite Mastotermes darwiniensis Froggatt (strain KMS2). Strain KMS2 is motile by a single polar flagellum. The isolate possesses desulfoviridin and catalase activity. The G+C content of its DNA is in the range of 54.5-55.5 mol% (strain KMS2). It respires hydrogen and different low molecular weight organic compounds in the presence of sulfate, thiosulfate, and sulfite, and also oxygen. The isolated strain ferments pyruvate. Fastest growth with a doubling time of 12.5 h was obtained at 37°C and not at 28°C, the temperature at which the termites were grown. The isolate showed a 16S rDNA seque…
The evolution of the heat-shock protein GroEL from Buchnera, the primary endosymbiont of aphids, is governed by positive selection
2002
The heat-shock protein GroEL is a double-ring-structured chaperonin that assists the folding of many newly synthesized proteins in Escherichia coli and the refolding in vitro, with the cochaperonin GroES, of conformationally damaged proteins. This protein is constitutively overexpressed in the primary symbiotic bacteria of many insects, constituting approximately 10% of the total protein in Buchnera, the primary endosymbiont of aphids. In the present study, we perform a maximum likelihood (ML) analysis to unveil the selective constraints in GroEL. In addition, we apply a new statistical approach to determine the patterns of evolution in this highly interesting protein. The main conclusion d…
Phylogeography and genetic variation of Triatoma dimidiata, the main Chagas disease vector in Central America, and its position within the genus Tria…
2008
Background Among Chagas disease triatomine vectors, the largest genus, Triatoma, includes species of high public health interest. Triatoma dimidiata, the main vector throughout Central America and up to Ecuador, presents extensive phenotypic, genotypic, and behavioral diversity in sylvatic, peridomestic and domestic habitats, and non-domiciliated populations acting as reinfestation sources. DNA sequence analyses, phylogenetic reconstruction methods, and genetic variation approaches are combined to investigate the haplotype profiling, genetic polymorphism, phylogeography, and evolutionary trends of T. dimidiata and its closest relatives within Triatoma. This is the largest interpopulational …
Molecular Apomorphies in the Secondary and Tertiary Structures of Length-Variable Regions (LVRs) of 18S rRNA Shed Light on the Systematic Position of…
2023
The SSU nrDNA, a small subunit of the nuclear ribosomal DNA (coding 18S rRNA), is one of the most frequently sequenced genes in molecular studies in Hexapoda. In insects, including true bugs (Hemiptera: Heteroptera), only its primary structures (i.e., aligned sequences) are predominantly used in phylogenetic reconstructions. It is known that including RNA secondary structures in the alignment procedure is essential for improving accuracy and robustness in phylogenetic tree reconstruction. Moreover, local plasticity in rRNAs might impact their tertiary structures and corresponding functions. To determine the systematic position of Thaumastellidae within the superfamily Pentatomoidea, the sec…