Search results for "homology"
showing 10 items of 770 documents
External derivations of internal groupoids
2008
If His a G-crossed module, the set of derivations of Gin H is a monoid under the Whitehead product of derivations. We interpret the Whitehead product using the correspondence between crossed modules and internal groupoids in the category of groups. Working in the general context of internal groupoids in a finitely complete category, we relate derivations to holomorphisms, translations, affine transformations, and to the embedding category of a groupoid. (C) 2007 Elsevier B.V. All rights reserved.
Origin of neuronal-like receptors in Metazoa: cloning of a metabotropic glutamate/GABA-like receptor from the marine sponge Geodia cydonium.
1999
To date, no conclusive evidence has been presented for the existence of neuronal-like elements in Porifera (sponges). In the present study, isolated cells from the marine sponge Geodia cydonium are shown to react to the excitatory amino acid glutamate with an increase in the concentration of intracellular calcium [Ca2+]i. This effect can also be observed when the compounds L-quisqualic acid (L-QA) or L-(+)-2-amino-4-phosphonobutyric acid (L-AP-4) are used. The effect of L-QA and L-AP-4, both agonists for metabotropic glutamate receptors (mGluRs), can be abolished by the antagonist of group I mGluRs, (RS)-alpha-methyl-4-carboxyphenylglycine. These data suggest that sponge cells contain an mG…
Vimentin and desmin of a cartilaginous fish, the shark Scyliorhinus stellaris: Sequence, expression patterns and in vitro assembly
2002
In the shark Scyliorhinus stellaris we have biochemically identified and cDNA-cloned orthologs of human vimentin and desmin, SstV and SstD, as deduced from immunoblotting and sequence alignment with teleost, frog and human vimentin and desmin, respectively. This allowed us to further clarify the relationship of previously identified lower vertebrate intermediate filament proteins to mammalian vimentin and desmin. Immunofluorescence microscopy with antibodies H5 and VIM13.2 showed vimentin expression in shark eye and brain and absence in epithelia, which resembles the situation in higher vertebrates. In addition, SstV is expressed in many mesenchymal cell types which corresponds to the case …
Differentiation capacity of epithelial cells in the sponge Suberites domuncula.
2004
Sponges (phylum Porifera) represent the oldest metazoans. Their characteristic metazoan adhesion molecules and transcription factors enable them to establish a complex "Bauplan" ; three major differentiated cell types (epithelial cells, skeletal cells/sclerocytes, and contractile cells) can be distinguished. Since no molecular markers are as yet available to distinguish these somatic cells or the corresponding embryonic cells from which they originate, we have selected the following three genes for their characterization: noggin (a signaling molecule in development), a caspase that encodes an apoptotic molecule, and silicatein. Silicatein is an enzyme that is involved in the synthesis of si…
Zebrafish vimentin: molecular characterization, assembly properties and developmental expression
1998
To provide a basis for the investigation of the intermediate filament (IF) protein vimentin in one of the most promising experimental vertebrate systems, the zebrafish (Danio rerio), we have isolated a cDNA clone of high sequence identity to and with the characteristic features of human vimentin. Using this clone we produced recombinant zebrafish vimentin and studied its assembly behaviour. Unlike other vimentins, zebrafish vimentin formed unusually thick filaments when assembled at temperatures below 21 degrees C. At 37 degrees C few filaments were observed, which often also terminated in aggregated masses, indicating that its assembly was severely disturbed at this temperature. Between 21…
The cohomology of a variation of polarized Hodge structures over a quasi-compact Kähler manifold
2007
In this article, we consider the cohomologies with coefficients in a variation of polarized Hodge structures on a quasi-compact Kaehler manifold. We show that the L 2 L^2 -Dolbeault cohomology can be identified with the L 2 L^2 cohomology; we also give several direct applications of the result above.
Algebraic de Rham Cohomology
2017
Let k be a field of characteristic zero. We are going to define relative algebraic de Rham cohomology for general varieties over k, not necessarily smooth.
Sponge Bcl-2 homologous protein (BHP2-GC) confers distinct stress resistance to human HEK-293 cells
2001
It is established that sponges, the phylogenetically oldest still extant phylum of Metazoa, possess key molecules of the apoptotic pathways, that is members from the Bcl-2 family and a pro-apoptotic molecule with death domains. Here we report on transfection studies of human cells with a sponge gene, GCBHP2. Sponge tissue was exposed to heat shock and tributyltin, which caused an upregulation of gene expression of GCBHP2. The cDNA GCBHP2 was introduced into human HEK-293 cells and mouse NIH-3T3 cells; the stable transfection was confirmed by the identification of the transcripts, by Western blotting as well as by immunofluorescence using antibodies raised against the recombinant polypeptide…
Genetic rearrangement of the atzAB atrazine-degrading gene cassette from pADP1::Tn5 to the chromosome of Variovorax sp. MD1 and MD2
2007
International audience; We report the characterization of the rearrangement phenomena responsible for the movement of the atrazine-degrading atzA and B genes from pADP1::Tn5 to the chromosome of Variovorax sp. MD1 and MD2. Long PCRs and Southern blot analyses revealed that the two genes forming a gene cassette moved in a unique rearrangement event. It also revealed that the boundaries of the plasmid sequence inserted in the chromosome correspond to IS1071or to sequences close to IS1071. It suggests that this genetic rearrangement could result from the transposition of the composite transposon delimited by IS1071 insertion sequences and containing atzA and atzB genes. In addition, for MD1 an…
Mutilation of RNA phage Qβ virus-like particles: from icosahedrons to rods
2000
Icosahedral virus-like particles (VLPs) of RNA phage Qbeta are stabilized by four disulfide bonds of cysteine residues 74 and 80 within the loop between beta-strands F and G (FG loop) of the monomeric subunits, which determine the five-fold and quasi-six-fold symmetry contacts of the VLPs. In order to reduce the stability of Qbeta VLPs, we mutationally converted the amino acid stretch 76-ANGSCD-81 within the FG loop into the 76-VGGVEL-81 sequence. It led to production in Escherichia coli cells of aberrant rod-like Qbeta VLPs, along with normal icosahedral capsids. The length of the rod-like particles exceeded 4-30 times the diameter of icosahedral Qbeta VLPs.