Search results for "phylogeny"
showing 10 items of 1398 documents
Molecular Evolution of Apoptotic Pathways: Cloning of Key Domains from Sponges (Bcl-2 Homology Domains and Death Domains) and Their Phylogenetic Rela…
2000
Cells from metazoan organisms are eliminated in a variety of physiological and pathophysiological processes by apoptosis. In this report, we describe the cloning and characterization of molecules from the marine sponges Geodia cydonium and Suberites domuncula, whose domains show a high similarity to those that are found in molecules of the vertebrate Bcl-2 superfamily and of the death receptors. The Bcl-2 proteins contain up to four Bcl-2 homology regions (BH). Two Bcl-2-related molecules have been identified from sponges that are provided with two of those regions, BH1 and BH2, and are termed Bcl-2 homology proteins (BHP). The G. cydonium molecule, BHP1_GC, has a putative size of 28,164, w…
Caspase-mediated apoptosis in sponges: cloning and function of the phylogenetic oldest apoptotic proteases from Metazoa
2003
AbstractSponges (phylum Porifera) represent the phylogenetically oldest metazoan phylum. These animals have complex cell adhesion and powerful immune systems which allow the formation of a distinct body plan. Consequently, an apoptotic machinery has to be predicted that allows sponges to eliminate unwanted cells accumulating during development. With the marine sponge Geodia cydonium, it is shown that allografts of these animals undergo apoptosis as demonstrated by apoptotic DNA fragmentation. Extracts from allografts contain an enzymic activity characteristic for caspases; as substrate to determine the cleavage activity, Ac-DEVD-AMC was applied. cDNAs encoding predicted caspase-3-related pr…
Selection on Coding Regions Determined Hox7 Genes Evolution
2003
The important role of Hox genes in determining the regionalization of the body plan of the vertebrates makes them invaluable candidates for evolutionary analyses regarding functional and morphological innovation. Gene duplication and gene loss led to a variable number of Hox genes in different vertebrate lineages. The evolutionary forces determining the conservation or loss of Hox genes are poorly understood. In this study, we show that variable selective pressures acted on Hox7 genes in different evolutionary lineages, with episodes of positive selection occurring after gene duplications. Tests for functional divergence in paralogs detected significant differentiation in a region known to …
Cytoglobin: A Novel Globin Type Ubiquitously Expressed inVertebrate Tissues
2002
Vertebrates possess multiple respiratory globins that differ in terms of structure, function, and tissue distribution. Three types of globins have been described so far: hemoglobin facilitates the transport of oxygen in the blood, myoglobin serves oxygen transport and storage in the muscle, and neuroglobin has a yet unidentified function in nerve cells. Here we report the identification of a fourth and novel type of globin in mouse, man, and zebrafish. It is expressed in apparently all types of human tissue and therefore has been called cytoglobin (CYGB). Mouse and human CYGBs comprise 190 amino acids; the zebrafish CYGB, 174 amino acids. The human CYGB gene is located on chromosome 17q25. …
Two α subunits and one β subunit of meprin zinc-endopeptidases are differentially expressed in the zebrafish Danio rerio
2007
Abstract Meprins are members of the astacin family of metalloproteases expressed in epithelial tissues, intestinal leukocytes and certain cancer cells. In mammals, there are two homologous subunits, which form complex glycosylated disulfide-bonded homo- and heterooligomers. Both human meprin α and meprin β cleave several basement membrane components, suggesting a role in epithelial differentiation and cell migration. There is also evidence that meprin β is involved in immune defence owing to its capability of activating interleukin-1β and the diminished mobility of intestinal leukocytes in meprin β-knockout mice. Here we show for the first time by reverse transcription PCR, immunoblotting a…
A Globin Gene of Ancient Evolutionary Origin in Lower Vertebrates: Evidence for Two Distinct Globin Families in Animals
2004
Hemoglobin, myoglobin, neuroglobin, and cytoglobin are four types of vertebrate globins with distinct tissue distributions and functions. Here, we report the identification of a fifth and novel globin gene from fish and amphibians, which has apparently been lost in the evolution of higher vertebrates (Amniota). Because its function is presently unknown, we tentatively call it globin X (GbX). Globin X sequences were obtained from three fish species, the zebrafish Danio rerio, the goldfish Carassius auratus, and the pufferfish Tetraodon nigroviridis, and the clawed frog Silurana tropicalis. Globin X sequences are distinct from vertebrate hemoglobins, myoglobins, neuroglobins, and cytoglobins.…
Side-stepping secondary symbionts: widespread horizontal transfer across and beyond the Aphidoidea.
2003
To elucidate the co-evolutionary relationships between phloem-feeding insects and their secondary, or facultative, bacterial symbionts, we explore the distributions of three such microbes--provisionally named the R-type (or PASS, or S-sym), T-type (or PABS), and U-type--across a number of aphid and psyllid hosts through the use of diagnostic molecular screening techniques and DNA sequencing. Although typically maternally transmitted, phylogenetic and pairwise divergence analyses reveal that these bacteria have been independently acquired by a variety of unrelated insect hosts, indicating that horizontal transfer has helped to shape their distributions. Based on the high genetic similarity b…
Receptor protein-tyrosine phosphatases: origin of domains (catalytic domain, Ig-related domain, fibronectin type III module) based on the sequence of…
2001
Abstract Reversible tyrosine phosphorylation of proteins is one of the major regulatory physiological events in response to cell-cell- and cell-matrix contact in Metazoa. Previously it was documented that the tyrosine phosphorylating enzymes, the tyrosine kinases (TKs), are autapomorphic characters of Metazoa, including sponges. In this paper the tyrosine dephosphorylating enzymes, the protein-tyrosine phosphatases (PTPs), are studied which can be grouped into two subfamilies, the soluble PTPs and the receptor PTPs (RPTPs). PTPs are characterized by one PTPase domain which interestingly comprises sequence similarity to yeast PTPs. In contrast to the PTPs, the RPTPs – which have been found o…
Expression of one sponge Iroquois homeobox gene in primmorphs from Suberites domuncula during canal formation
2003
SUMMARY Sponges (Porifera) represent the evolutionary oldest multicellular animals. They are provided with the basic molecules involved in cell–cell and cell–matrix interactions. We report here the isolation and characterization of a complementary DNA from the sponge Suberites domuncula coding for the sponge homeobox gene, SUBDOIRX-a. The deduced polypeptide with a predicted Mr of 44,375 possesses the highly conserved Iroquois-homeodomain. We applied in situ hybridization to localize Iroquois in the sponge. The expression of this gene is highest in cells adjacent to the canals of the sponge in the medulla region. To study the expression of Iroquois during development, the in vitro primmorph…
Molecular diversity and growth features of Flavobacterium columnare strains isolated in Finland
2006
ABSTRACT: Columnaris disease caused by Flavobacterium columnare is a problem in fish farmingworldwide. During the last 15 yr, outbreaks have started to emerge in Finland. Flavobacteriumcolumnare Type Strain NCIMB 2248 T and 30 Finnish F. columnare isolates were studied usinganalysis of 16S rDNA by restriction-fragment length polymorphism (16S RFLP), length heterogeneityanalysis of polymerase chain reaction (LH-PCR) products, automated ribosomal intergenic spaceranalysis (ARISA), and 16S rDNA sequence analysis. All isolates fell into RFLP Genomovar I and hadthe same length in the LH-PCR analysis. Based on ARISA, 8 genetically different strains wereselected for further analyses. The growth of…