Search results for "Suberites"
showing 10 items of 135 documents
The complete set of ribosomal proteins from the marine sponge Suberites domuncula
2005
The siliceous marine sponge Suberites domuncula is a member of the most ancient and simplest extant phylum of multicellular animals-Porifera, which have branched off first from the common ancestor of all Metazoa. We have determined primary structures of 79 ribosomal proteins (r-proteins) from S. domuncula: 32 proteins from the small ribosomal subunit and 47 proteins from the large ribosomal subunit. Only L39 and L41 polypeptides (51 and 25 residues long in rat, respectively) are missing. The sponge S. domuncula is, after nematode Caenorhabditis elegans and insect Drosophila melanogaster the third representative of invertebrates with known amino acid sequences of all r-proteins. The comparis…
Isolation of the silicatein-α interactor silintaphin-2 by a novel solid-phase pull-down assay.
2011
The skeleton of siliceous sponges consists of amorphous biogenous silica (biosilica). Biosilica formation is driven enzymatically by means of silicatein(s). During this unique process of enzymatic polycondensation, skeletal elements (spicules) that enfold a central proteinaceous structure (axial filament), mainly comprising silicatein, are formed. However, only the concerted action of silicatein and other proteins can explain the genetically controlled diversity of spicular morphotypes, from simple rods with pointed ends to intricate structures with up to six rays. With the scaffold protein silintaphin-1, a first silicatein interactor that facilitates the formation of the axial filament and…
The role of the silicatein-alpha interactor silintaphin-1 in biomimetic biomineralization.
2008
Biosilicification in sponges is initiated by formation of proteinaceous filaments, predominantly consisting of silicateins. Silicateins enzymatically catalyze condensation of silica nanospheres, resulting in symmetric skeletal elements (spicules). In order to create tailored biosilica structures in biomimetic approaches it is mandatory to elucidate proteins that are fundamental for the assembly of filaments. Silintaphin-1 is a core component of modularized filaments and also part of a spicule-enfolding layer. It bears no resemblance to other proteins, except for the presence of an interaction domain that is fundamental for its function as scaffold/template. In the presence of silicatein sil…
Dissection of the structure-forming activity from the structure-guiding activity of silicatein: a biomimetic molecular approach to print optical fibe…
2020
Silicateins, a group of proteins forming the proteinaceous axial filaments of the inorganic biosilica spicules of the siliceous sponges, are unique in their dual function to exhibit both structure-guiding (providing the structural platform for the biosilica product) and structure-forming activities (enzymatic function: biosilica synthesis from ortho-silicate). The primary translation product of the silicatein gene comprises a signal peptide, a pro-peptide and, separated by an autocatalytic cleavage site glutamine/aspartic acid [Q/D], the sequence of the mature silicatein protein. In order to dissect the biocatalytic, structure-forming activity of silicatein from its structure-guiding functi…
Isolation and characterization of two T-box genes from sponges, the phylogenetically oldest metazoan taxon
2003
It is now well established that all metazoan phyla derived from one common ancestor, the hypothetical Urmetazoa. Due to the basal position of Porifera (Demospongiae) in the phylogenetic tree of Metazoa, studies on the mechanisms controlling the development of these animals can provide clues on the understanding of the origin of multicellular animals and on how the first organization of the body plan evolved. In this report we describe the isolation and genomic characterization of two T-box genes from the siliceous sponge Suberites domuncula. The phylogenetic analysis classifies one into the subfamily of Brachyury, Sd-Bra, and the second into the Tbx2 subfamily, Sd-Tbx2. Analyses of the Sd-B…
Species-Specific Aggregation Factor in Sponges
1978
An aggregation receptor (AR) from the siliceous sponge Suberites domuncula has been isolated and purified by chromatography to about 55% purity. The AR consists primarily of neutral carbohydrate and is characterized by a buoyant density of 1.59 g/ml and by an apparent molecular weight of 42,500. The average density of the AR on Suberite cells is about 3.8 × 10 5 per μm 2 . The AR contains considerable amounts of hexuronic acid. The isolated AR can bind not only to receptor-depleted Suberites cells but also to receptor depleted cells from another siliceous species (Geodia cydontum) . After being charged with Suberites ARs, Geodia cells form aggregates in the presence of the species-specific …
Formation of silicones mediated by the sponge enzyme silicatein-α
2010
The sponge-restricted enzyme silicatein-α catalyzes in vivo silica formation from monomeric silicon compounds from sea water (i.e. silicic acid) and plays the pivotal role during synthesis of the siliceous sponge spicules. Recombinant silicatein-α, which was cloned from the demosponge Suberites domuncula (phylum Porifera), is shown to catalyze in vitro condensation of alkoxy silanes during a phase transfer reaction at neutral pH and ambient temperature to yield silicones like the straight-chained polydimethylsiloxane (PDMS). The reported condensation reaction is considered to be the first description of an enzymatically enhanced organometallic condensation reaction.
Molecular Mechanism of Spicule Formation in the Demosponge Suberites domuncula: Silicatein-Collagen-Myotrophin
2003
In living organisms four major groups of biominerals exist: (1) iron compounds, which are restricted primarily to Prokaryota; (2) calcium phosphates, found in Metazoa; (3) calcium carbonates, used by Prokaryota, Protozoa, Plantae, Fungi and Metazoa and (4) silica (opal) present in sponges and diatoms (reviewed in: Bengtson 1994; Baeuerlein 2000). It is surprising that the occurrence of silica as a major skeletal element is restricted to some Protozoa and to sponges (Porifera). The element silicon (Si) contributes to 28% of the earth crust and is - after oxygen - the second most abundant element on earth (Windholz 1983).
A cryptochrome-based photosensory system in the siliceous sponge Suberites domuncula (Demospongiae)
2010
Based on the light-reactive behavior of siliceous sponges, their intriguing quartz glass-based spicular system and the existence of a light-generating luciferase [Muller WEG et al. (2009) Cell Mol Life Sci 66, 537–552], a protein potentially involved in light reception has been identified, cloned and recombinantly expressed from the demosponge Suberites domuncula. Its sequence displays two domains characteristic of cryptochrome, the N-terminal photolyase-related region and the C-terminal FAD-binding domain. The expression level of S. domuncula cryptochrome depends on animal’s exposure to light and is highest in tissue regions rich in siliceous spicules; in the dark, no cryptochrome transcri…
Apposition of silica lamellae during growth of spicules in the demosponge Suberites domuncula: Biological/biochemical studies and chemical/biomimetic…
2006
Recently it has been discovered that the formation of the siliceous spicules of Demospongiae proceeds enzymatically (via silicatein) and occurs matrix guided (on galectin strings). In addition, it could be demonstrated that silicatein, if immobilized onto inorganic surfaces, provides the template for the synthesis of biosilica. In order to understand the formation of spicules in the intact organism, detailed studies with primmorphs from Suberites domuncula have been performed. The demosponge spicules are formed from several silica lamellae which are concentrically arranged around the axial canal, harboring the axial filament composed of silicatein. Now we show that the appositional growth o…