Search results for "Base Sequence"
showing 10 items of 1146 documents
Assay for O6-alkylguanine-DNA-alkyltransferase using oligonucleotides containing O6-methylguanine in a BamHI recognition site as substrate
1992
Abstract Double-stranded oligonucleotides, 40 bases in length containing an O 6 -methylguanine in a Bam HI restriction site, were developed as substrates for the determination of human O 6 -alkylguanine-DNA-alkyltransferase (AGT). The assay proved highly sensitive and quantitative. After incubation of the 5′-end-labeled oligonucleotides with cell homogenates of peripheral blood lymphocytes, the DNA was digested with Bam HI. Cleavage with this restriction enzyme did not occur in the O 6 -methylguanine-containing oligonucleotide unless the fragment was repaired. The cleaved oligonucleotide was separated from the intact parent oligonucleotide by reverse-phase high-performance liquid chromatogr…
Molecular characterization of the zerknüllt region of the Antennapedia complex of D. subobscura.
1995
We have characterized at the molecular level the zerknullt (zen) region of the Drosophila subobscura Antennapedia complex. The sequence comparison between D. subobscura and D. melanogaster shows an irregular distribution of the conserved and diverged regions, with the homeobox and a putative activating domain completely conserved. Comparisons of the promoter sequence and pattern of expression of the gene during development suggest that the regulation of zen has been conserved during evolution. The conservation of zen expression in a subpopulation of the polar cells indicates the existence of an important role in such cells. We describe a transitory segmented pattern of expression of zen in …
Plasmid-encoded anthranilate synthase (TrpEG) in Buchnera aphidicola from aphids of the family pemphigidae
1999
Aphids are dependent on an intracellular symbiont (Buchnera aphidicola, Proteobacteria) for normal growth and reproduction (7, 19, 45). The bacteria reside in specialized cells in the aphid hemocele and are transmitted maternally through infection of eggs or embryos (11, 26). Phylogenetic studies have revealed two major characteristics of the evolutionary history of the association (37, 39); (i) the symbiosis had a single origin, dated about 150 million to 250 million years ago; and (ii) host and symbiont lineages have since diverged strictly in parallel. The association, like other symbioses in insects feeding on restricted and unbalanced diets, is thought to have a nutritional basis (5–7,…
Engineering a 2D protein-DNA crystal.
2005
(Figure Presented) Weaving with DNA: A DNA-binding protein was used to control the structure of a self-assembled 2D crystal. In the absence of protein, four oligonucleotides hybridize to form a Kagome lattice of interwoven double helices with p3 symmetry (see image). Addition of protein RuvA during assembly changes the symmetry and connectivity to give a DNA-protein crystal with an approximately square unit cell. © 2005 Wiley-VCH Verlag GmbH and Co. KGaA.
A new species of Pythium isolated from the Burgundy region in France.
1998
Pythium nodosum sp. nov. has been isolated from a soil sample taken in the Burgundy region in France. The fungus has spherical to variously shaped proliferating sporangia, smooth-walled oogonia which are crowded with different antheridial branches making a complicated knot around the former, and aplerotic oospores. Morphological and reproductive aspects of Pythium nodosum as well as the PCR of the internal transcribed spacer (ITS1) of the ribosomal nuclear DNA coupled with restriction fragment length polymorphism analysis are described here. The nucleotide sequences of ITS1 encoding 5.8S rRNA is also given.
Pythium ornacarpum: a new species with ornamented oogonia isolated from soil in France
1999
Pythium ornacarpum sp. nov. was isolated from a soil sample taken from Genlis in the Burgundy region of France. This species is unique because of its ornamented oogonia which are completely surrounded by antheridial filaments. The fungus is closely related to Pythium echinulatum Matthews. Morphological and reproductive aspects of this species as well as a study by PCR of the sequence of the internal transcribed spacer (ITS1) of the nuclear ribosomal gene and its comparison with related species are described here. The nucleotide sequence of the ITS1 region flaking the 5.8S rRNA of this species and other related species are also given here.
A new species of Pythium with filamentous sporangia having pectinolytic activities, isolated in the Burgundy region of France.
2001
A new species, Pythium pectinolyticum (F-83.1), isolated from soil samples taken in the Burgundy region is being described here. This species is characterised by its filamentous non-inflated type of sporangia, smooth-walled mostly catenulate oogonia and very rare antheridia. This fungus is a very slow-growing organism on most of the solid media, but it grows well in liquid media and also on those containing pectin as the sole source of carbon. Morphological features are described here together with the sequences of the internal transcribed spacer 1 region of the nuclear ribosomal DNA of the fungus, its comparison with related species, and its pectinolytic behaviour.
A new species of Pythium with ornamented oogonia: morphology, taxonomy, internal transcribed spacer region of its ribosomal RNA, and its comparison w…
2006
Pythium spiculum sp. nov. was isolated from soil samples taken in a vineyard in the Burgundian region of France and from different locations in Spain and Portugal. The oomycete has spiny oogonia and does not sporulate readily. It resembles Pythium mamillatum Meurs, but has its own distinguishing characteristics. It also exhibits sickle-shaped as well as spherical appressoria which at times are associated with sex organs like those found in Pythium abappressorium Paulitz and Pythium contiguanum Paul. Sequencing of the internal transcribed spacer region of its nuclear ribosomal DNA and a close look at its morphological characters have now enabled us to describe it as a new species. The intern…
Pythium terrestris, a new species isolated from France, its ITS region, taxonomy and its comparison with related species
2002
Pythium terrestris (F-78) was isolated from soil samples taken in Lille in northern France. Its morphology resembles that of Pythium rostratum, and Pythium longandrum, a recently described species. However the antheridial and sporangial characteristics of this new species are unique. The fungus does not sporulate, the sporangium germinates directly into mycelium through germ tubes. The oogonia of P. terrestris are normally provided with hypogynous and monoclinous antheridia, at times the monoclinous antheridial branches wrap around the oogonia forming a complicated knot. Morphological features of this new species, together with the sequences of the internal transcribed spacer (ITS) region o…
Putative evolutionary origin of plasmids carrying the genes involved in leucine biosynthesis in Buchnera aphidicola (endosymbiont of aphids)
1997
An 8.5-kb plasmid encoding genes (leuABCD) involved in leucine biosynthesis and a small plasmid of 1.74 kb of yet unknown function were found in the intracellular symbiont, Buchnera aphidicola, of two divergent aphid species, Thelaxes suberi and Tetraneura caerulescens, respectively. The leuABCD-carrying plasmid (pBTs1) was amplified from total aphid DNA by inverse long PCR, using outwardly oriented oligonucleotide primers specific to leuA. The resulting 8.2-kb PCR fragment as well as the 1.74-kb plasmid (pBTc1) were cloned and sequenced. pBTs1 differed from a previously described B. aphidicola plasmid (pRPE) of the aphid Rhopalosiphum padi by the presence of a small heat shock gene (ibp) a…