Search results for "homology"

On operads, bimodules and analytic functors

2017

We develop further the theory of operads and analytic functors. In particular, we introduce a bicategory that has operads as 0-cells, operad bimodules as 1-cells and operad bimodule maps as 2-cells, and prove that this bicategory is cartesian closed. In order to obtain this result, we extend the theory of distributors and the formal theory of monads.

HP2-bundles and elliptic homology

1993

Real quadrics in C n , complex manifolds and convex polytopes

2006

In this paper, we investigate the topology of a class of non-Kähler compact complex manifolds generalizing that of Hopf and Calabi-Eckmann manifolds. These manifolds are diffeomorphic to special systems of real quadrics Cn which are invariant with respect to the natural action of the real torus (S1)n onto Cn. The quotient space is a simple convex polytope. The problem reduces thus to the study of the topology of certain real algebraic sets and can be handled using combinatorial results on convex polytopes. We prove that the homology groups of these compact complex manifolds can have arbitrary amount of torsion so that their topology is extremely rich. We also resolve an associated wall-cros…

Sequences of isopenicillin N synthetase genes suggest horizontal gene transfer from prokaryotes to eukaryotes

1990

Evolutionary distances between bacterial and fungal isopenicillin N synthetase (IPNS) genes have been compared to distances between the corresponding 5S rRNA genes. The presence of sequences homologous to the IPNS gene has been examined in DNAs from representative prokaryotic organisms and Ascomycotina. The results of both analyses strongly support two different events of horizontal transfer of the IPNS gene from bacteria to filamentous fungi. This is the first example of such a type of transfer from prokaryotes to eukaryotes.

Genome organization and nucleotide sequence of human papillomavirus type 39

1991

The 7833-bp nucleotide sequence of human papillomavirus type 39 (HPV39), which is associated with genital intraepithelial neoplasias and invasive carcinomas, has been determined. The genome organization deduced from the sequence shares characteristic features with other genital papillomaviruses. According to sequence comparisons, HPV39 most closely resembles HPV18 and may be a member of a subgroup of genital papillomaviruses distinct from the HPV16/31/33 group. As a novel feature, we report a 1.3-kb open reading frame on the DNA strand which lacks major open reading frames in the other sequenced HPV genomes.

Sequence and evolution of the gene for the monomeric globin I and its linkage to genes coding for dimeric globins in the insect Chironomus thummi.

1995

We isolated genomic clones containing sequences encoding globins I and IA from a Chironomus thummi thummi genomic library. Three clones contain globin IA (ctt-1A) genes, while one contains a globin I (ctt-1) gene. The coding regions of the four genes are identical except for the single base substitution accounting for the globin I/IA polymorphism. The noncoding DNA flanking the coding region is more than 98% similar, confirming a previous hypothesis that the globin ctt-1 and ctt-1A genes are alleles. Hemoglobins I and IA are monomeric in the insect hemolymph. Earlier in situ hybridization studies suggested that monomeric and dimeric globin genes are clustered at different chromosomal loci. …

Cloning and Expression of the mRNA of Human Galectin-4, an S-type Lectin Down-Regulated in Colorectal Cancer

1997

We are interested in the characterization of genes whose expressions in the colon are modified during colorectal carcinogenesis. Our approach was to establish the phenotype of a colon tumor by partial sequencing of a large number of transcripts, then to select mRNAs of potential interest by differential screening with complex probes from normal or cancerous colon. In this paper, we report the cloning and sequencing of a mRNA strongly underexpressed in colorectal cancer. It corresponded to a protein comprising 323 amino acids, that appeared to be human galectin-4 on the basis of 76% and 79% amino acid identity to the rat and pig counterparts, respectively. Tissue distribution analysis showed…

Mutations in the β-tropomyosin (TPM2) gene – a rare cause of nemaline myopathy

2002

Nemaline myopathy is a clinically and genetically heterogeneous muscle disorder. In the nebulin gene we have detected a number of autosomal recessive mutations. Both autosomal dominant and recessive mutations have been detected in the genes for alpha -actin and alpha -tropomyosin 3. A recessive mutation causing nemaline myopathy among the Old Order Amish has recently been identified in the gene for slow skeletal muscle troponin T. As linkage studies had shown that at least one further gene exists for nemaline myopathy, we investigated another tropomyosin gene expressed in skeletal muscle, the beta -tropomyosin 2 gene. Screening 66 unrelated patients, using single strand conformation polymor…

Minisatellite DNA Probe MZ 1.3: Application in Paternity Testing and Estimate of the Number of Genetic Loci

1990

The use of hypervariable DNA minisatellite probes recognizing repetitive genomic DNA sequences has become a valuable and powerful tool in paternity testing as well as in forensic stain analysis (Jeffreys et al. 1985, 1987; Werrett et al. 1988). It has been shown that bacteriophage Ml3 DNA can also be used to obtain hypervariable DNA restriction fragment patterns in humans and other species (Vassart et al. 1987). To obtain more informative and specific fragment patterns for the DNA ‘fingerprint’ analysis in man, we have used Ml3 DNA as a probe to screen a human genomic library. Thus, we have isolated the minisatellite DNA probe MZ 1.3 (Schacker et al., in press). MZ 1.3 is a 1.9 kb fragment …

A variable intron distribution in globin genes of Chironomus: evidence for recent intron gain

1998

The intron positions found in globin genes of plants, protozoa and invertebrates have been interpreted as evidence for a three-intron-four-exon structure of the ancestral globin gene. In particular, the so-called 'central' introns, which are not found in vertebrate globin genes but are present in a variety of invertebrate and plant species, have been used as an argument for an ancestral gene structure featuring three introns. We have analyzed the presence or absence of central introns in the Gb genes 2beta, 9 and 7A of various European and Australasian species of the insect Chironomus. We find unrelated central introns at different positions in some of the species investigated, while other …