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At least 73 records · Page 4Linked to original sources
PubMed2000

Lectin histochemistry and ultrastructure of microgranular cells in Cinachyra tarentina (Porifera, Demospongiae).

A histochemical study is described that characterizes microgranular cells of the demosponge Cinachyra tarentina (C. tarentina) with the use of routine staining methods for mucosubstances, lectin histochemistry and electron microscopy. Microgranular cells are rare or absent in other species of sponges, but abundant in this species. Microgranular cells are present in both ectosome and mesohyl, particularly along the canal of the aquiferous system and around spicule holes. Inclusions of microgranular cells and the extracellular matrix were particularly positive for acidic glycoproteins with abundant sulfated ester groups and glycosidic residues containing GalNAc and Galbeta1,3GalNAc. Terminal L-fucose bound to the penultimate GalNAc residues and/or difucosylated oligosaccharides were present as well. Our results suggest that soybean lectin (SBA), peanut lectin (PNA), and winged pea lectin (WPA) are valuable markers for identifying microgranular cells of C. tarentina. Electron microscopy revealed some of the microgranular cells to contain small smooth cytoplasmic vesicles originating from the Golgi complex and few electron-dense granules, others were characterized by numerous secretory granules and vacuoles formed by vesicle fusion and connected with the plasma membrane. Our results suggest that microgranular cells in C. tarentina contribute to the synthesis of glycoprotein components of the extracellular matrix.

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PubMed1986

Allograft rejection, autograft fusion and inflammatory responses to injury in Callyspongia diffusa (Porifera; Demospongia).

Sponges exhibit a variety of swift, cellular defence responses to protect self integrity. The sponge Callyspongia diffusa has been used to characterize the cytological changes that occur during allograft rejection, autograft fusion, and inflammation. Allogeneic contact results in fusion of the two exopinacoderms followed by an infiltration of mesohyl cells into the graft zone. As mesohyl cells accumulate, they form tissue bridges that span the graft interface. After a few days, the tissue bridges and the nearby cellular infiltrate become necrotic and slough off, which separates the allogeneic tissues. Autograft fusion begins similarly but cellular infiltration does not follow exopinacoderm fusion. Contacted exopinacocytes are redistributed, the endopinacoderms and choanosomes come into contact, and the grafted sponge tissues merge. Tissue damage exposes internal regions of the sponge to the external environment. In many areas of injury, exposed choanosome is sealed by infiltrating mesohyl cells. In other areas, exposed endopinacoderm appears to serve as new exopinacoderm. Cellular debris is removed by phagocytic archaeocytes and new exopinacoderm is regenerated over the damaged choanosome. No scars remain once the inflammatory infiltrate has dispersed. In general, mesohyl cells are involved in defence responses without an observed enrichment of any specific cell type. However, archaeocytes from rejecting sponges appear to line both sides of the allogeneic interface.

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PubMed1986

Allogeneic cell interactions during graft rejection in Callyspongia diffusa (Porifera, Demospongia); a study with monoclonal antibodies.

Many aspects of the cellular immune system in the marine sponge Callyspongia diffusa, have been defined by using artificially transplanted allogeneic tissues. Rejections show specificity of 'non-self' recognition, cytotoxic effector responses and short-term immunological memory. Histological investigations reveal a generalized mesohyl migration to the graft zone where archaeocytes line up at the allogeneic interface. Monoclonal antibodies (mAbs) raised to sponge cells have shown that little or no allogeneic cell mixing occurs at the graft interface and that certain mesohyl cell types do not appear to be directly involved in graft rejections. However, all mesohyl cell types are present in autograft fusion zones and in inflammatory responses to injury. The involvement of only some of the mesohyl cell types in graft rejections suggests specific interactions of an effector 'immunocyte'.

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PubMed2006

Rubritalea marina gen. nov., sp. nov., a marine representative of the phylum 'Verrucomicrobia', isolated from a sponge (Porifera).

A marine bacterium, strain Pol012(T), was isolated from the Mediterranean sponge Axinella polypoides and subsequently characterized as belonging to subphylum 1 of the phylum 'Verrucomicrobia'. Strain Pol012(T) was non-motile, Gram-negative, coccoid or rod-shaped and red in colour. The menaquinones MK-8 and MK-9 were detected. The G+C content of the genomic DNA was 50.9 mol%. Growth was possible at temperatures between 8 and 30 degrees C and at pH values between 6.8 and 8.2. The closest cultured relative of strain Pol012(T) was Akkermansia muciniphila (83 % sequence similarity), while the closest environmental 16S rRNA gene sequence was the marine clone Arctic96BD-2 (95 % sequence similarity). Strain Pol012(T) is the first marine pure-culture representative of 'Verrucomicrobia' subphylum 1 and represents a novel genus and species, for which the name Rubritalea marina gen. nov., sp. nov. is proposed. The type strain is Pol012(T) (=DSM 177716(T)=CIP 108984(T)).

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PubMed1993

A six-armed, tenascin-like protein extracted from the Porifera Oscarella tuberculata (Homosclerophorida).

A six-armed complex could be extracted from the marine sponge Oscarella tuberculata by a two-step incubation, first in Tris-buffered saline containing EDTA, then in Tris-buffered saline containing urea. The crude extracts contained, in addition, collagen fibrils with surface filaments, individual filaments resembling collagen molecules, and laminin/nidogen-like complexes. The extracts were subsequently purified by gel-filtration chromatography and low-pressure ion-exchange chromatography on DEAE-cellulose, then analyzed by SDS/PAGE and immunoblotting methods. A glycoprotein of high molecular mass was isolated, and reduced to subunits of 230 kDa. After transfer to nitrocellulose, both the complex and its subunits were faintly stained by antibodies against amphibian tenascin. Electron microscopy of the purified extracts demonstrated the presence of a large population of tenascin-like molecules and complexes of several molecules interacting with each other by their central globule.

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PubMed1970

Porifera: sudden sperm release by tropical Demonspongiae.

Three tropical marine demosponges inhabiting the deep coral reefs of Jamaica expel immense clouds of milky fluid from exhalant apertures. Analysis of samples shows this fluid to contain mature male gametes. The behavior is an individual or a population event in different species.

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PubMed2004

Kinetics and rhythm of body contractions in the sponge Tethya wilhelma (Porifera: Demospongiae).

Sponges of the species Tethya wilhelma display rhythmic body contractions, which were analyzed by digital timelapse imaging and semi-automated image analysis. For the first time, differential, quantitative data on sponge behaviour could be obtained. The sponges are able to reduce their body volume by up to 73.3% during regular contractions. Each contraction cycle follows a characteristic pattern of four phases, permitting analysis of the kinetics of contraction and expansion. Long-term observations (for >7 days) reveal that the sponge contractions display a day-night periodicity in which contraction cycles are significantly longer during the dark hours. The contractions seem to be mediated by the pinacoderm; they are triggered locally and spread over the sponge surface at 12.5 microm s(-1). If two individuals of a clone are fused, the individual contraction rhythm of both sponges persists for several days, until a single new individual sponge is formed with a synchronized rhythm. The reported results and techniques establish T. wilhelma as a model organism for research on the development of aneural signal transduction and integration during early Metazoan evolution.

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PubMed1997

Polyphyly of "sclerosponges" (Porifera, Demospongiae) supported by 28S ribosomal sequences.

To test the competing hypotheses of polyphyly and monophyly of "sclerosponges," sequences from the 5' end of 28S ribosomal RNA were obtained for Astrosclera willeyana, Acanthochaetetes wellsi, and six other demosponge species. Phylogenetic relationships deduced from parsimony and neighbor-joining analyses suggest that these sclerosponges belong to two different orders of Demospongiae: Astrosclera willeyana, being closely related to the Agelasidae, belongs to the Agelasida, Acanthochaetetes wellsi, being closely related to the Spirastrellidae, belongs to the Hadromerida. These results contradict the hypothesis that sclerosponges are monophyletic and imply that a massive calcareous skeleton has evolved independently in several lineages of sponges.

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PubMed2003

Effect of disturbance on assemblages: an example using porifera.

Extensive sponge assemblages are found in a number of habitats at Lough Hyne Marine Nature Reserve. These habitats are unusual in experiencing a range of environmental conditions, even though they are only separated by small geographic distances (1-500 m), reducing the possibility of confounding effects between study sites (e.g., silica concentrations and temperature). Sponge assemblages were examined on ephemeral (rocks), stable (cliffs), and artificial (slate panels) hard substrata from high- and low-energy environments that were used to represent two measures of disturbance (flow rate and habitat stability). Sponge assemblages varied considerably between habitat types such that only 26% (25 species) of species reported were common to both rock and cliff habitats. Seven species (of a total of 96 species) were found in the least-developed assemblages (slate panels) and were common to all habitats. Sponge assemblages on rocks and panels varied little between high- and low-energy environments, whereas assemblages inhabiting cliffs varied considerably. Assemblage composition was visualized using Bray-Curtis similarity analysis and Multi-Dimensional Scaling, which enabled differences and similarities between sponge assemblages to be visualized. Cliffs from high- and low-energy sites had different assemblage compositions compared to large rocks, small rocks, and panels, all of which had similar assemblages irrespective of environmental conditions. Differences in assemblages were partially attributed to sponge morphology (shape), as certain morphologies (e.g., arborescent species) were excluded from 2-D rock habitats. Other mechanisms were also considered responsible for the sponge assemblages associated with different habitats.

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PubMed2003

[Organic extracts with antimicrobian activity from Penicillium sp. (Moniliales) isolated from the sponge Ircinia felix (Porifera: Demospongiae)].

This research expresses the potential of the bacterial activity present in the organic extracts obtained from Penicillium sp., isolated from the esponge Irciniafelix. This activity was evaluated through agar diffusion test and Minimal Inhibitory Concentration (MIC). The susceptibility trials of organic fractions were carried out against Staphylococcus aureus, S. epidermidis, Bacillus cereus and B. subtilis. The use of the chromatographic techniques (CLV and TLC), permitted to obtain bioactive organic extracts of different polarities, of which only the EtOAc and MeOH fractions inhibited the growth of the bacteria used. Of the EtOAc fractionation, only fraction number 3 EtOAc/Hex presented greatest activity against the Gram-positive bacteria. Number 1 EtOAc/Hex fraction increased its activity against S. aureus (24 mm) and S. epidermidis (25 mm), which can be explained by the loss of possible antagonistic effect during the fractionation process. The CMI trials were carried out for the EtOAc number I subfraction against S. aureus, S. epidermidis, B. cereus and B. subtilis, wich was clinical interest, and shows the potential of this organic extract as antimicrobial agent.

Animals↗
PubMed1990

The role of microtubules for the movement of mitochondria in pinacocytes of fresh-water sponges (Spongillidae, Porifera).

In pinacocytes around the base of fresh-water sponges (Spongillidae) mitochondria move over long, straight paths, at an average speed of 1.3 micron/s. The application of colcemid (10(-4) M) has a distinct influence on mitochondrial movement: after 45 min the paths are dramatically shortened, after 90 min the periphery is devoid of mitochondria, and after 180 min all the mitochondria have aggregated in the perinuclear region. Three hours upon removal of colcemid, most mitochondria start to migrate away from the nuclear region along new paths and reach the boundary of the cell after 4 h of reculturing. These dynamics were analyzed in serial video frames. Immunocytochemical staining of comparable pinacocytes with a monoclonal tubulin-antibody reveals a characteristic system of unbranched, radially arranged microtubules extending from the nucleus to the boundary of the cell. After the application of colcemid (10(-4) M), progressively fewer and shorter microtubules are labeled. Four hours after removal of colcemid, the microtubular system is restored. The results of the present paper imply that mitochondrial movement in pinacocytes is dependent on the existence of an intact microtubular system.

Animals↗
PubMed1990

Condensation rhythm of fresh-water sponges (Spongillidae, Porifera).

The mesenchyme continuum of spongillids exhibits rhythmic changes that at first glance appear to be contractions. Actually, however, the process is a condensation initiated by the formation of punctate cell contacts and a rapid swelling of all mesenchymal cells. As the cells come into closer contact and the spaces between them are constricted, the volume of the mesenchyme shrinks, giving the impression of a contraction. It seems likely that rhythmic mesenchyme condensation assists the choanocyte chambers in pumping water through the sponge.

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PubMed1989

[Caroteno-protein complexes in Axinella verrucosa (Porifera: Demospongae)].

Carotenoproteins are common to a wide variety of animals, most notably invertebrates although other animal groups have been shown to have these complexes as well. In a previous paper alpha-carotene, renieratene, isorenieratene and an unknown isomer of renieratene were isolated, but at present nothing is known about nature of the carotenoid-protein complexes in A. verrucosa. In this paper we report our results about a carotenoid-protein complex extracted by TRITON X-100 and purified by Sephadex G 200 Fine and DEAE-Sephacel chromatography. This carotenoprotein had a molecular weight of ca. 390,000 dalton (Gel electrophoresis). SDS PAGE plate showed only a single polypeptide chain of ca. 50,000 dalton. The proteic band separated by PAGE plate electrophoresis showed the presence of lipids and glycids when stained respectively by Sudan Black B and by Schiff's reagent. The extract obtained without TRITON X-100 showed the presence of a similar carotenoid-protein complex, but because of the low proteic concentration this result should be confirmed.

Animals↗
PubMed1987

Structural and ultrastructural aspects of growth in Oscarella lobularis (Porifera, Demospongiae).

Light and electron microscopy were used to study projections emerging from areas of the sponge Oscarella lobularis. These projections seem to arise from foldings of the exopinacoderm, a process also involving mesohyl cells. Besides folding, exopinacocytes invaginate giving rise to small pockets. These may open directly to the outside and represent the precursors of flagellated chambers. Exopinacocytes lining pockets and spaces between projections transform into endopinacocytelike cells. As pockets become isolated from the exterior, cells further differentiate into choanocytes. Remodeling processes, involving fusion of adjacent protrusions and transformation of the intervening spaces into canals, eventually realize a functional aquiferous system. Allowing the sponge to increase its size, these events represent the steps of a growth mechanism.

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