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1.
Nat Commun ; 10(1): 3348, 2019 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-31350398

RESUMO

Most sponges have biomineralized spicules. Molecular clocks indicate sponge classes diverged in the Cryogenian, but the oldest spicules are Cambrian in age. Therefore, sponges either evolved spiculogenesis long after their divergences or Precambrian spicules were not amenable to fossilization. The former hypothesis predicts independent origins of spicules among sponge classes and presence of transitional forms with weakly biomineralized spicules, but this prediction has not been tested using paleontological data. Here, we report an early Cambrian sponge that, like several other early Paleozoic sponges, had weakly biomineralized and hexactine-based siliceous spicules with large axial filaments and high organic proportions. This material, along with Ediacaran microfossils containing putative non-biomineralized axial filaments, suggests that Precambrian sponges may have had weakly biomineralized spicules or lacked them altogether, hence their poor record. This work provides a new search image for Precambrian sponge fossils, which are critical to resolving the origin of sponge spiculogenesis and biomineralization.


Assuntos
Poríferos/metabolismo , Animais , Biomineralização , Fósseis , Paleontologia , Filogenia , Poríferos/classificação , Poríferos/ultraestrutura , Dióxido de Silício/metabolismo
2.
Mar Drugs ; 17(2)2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30717221

RESUMO

The bioactive bromotyrosine-derived alkaloids and unique morphologically-defined fibrous skeleton of chitin origin have been found recently in marine demosponges of the order Verongiida. The sophisticated three-dimensional (3D) structure of skeletal chitinous scaffolds supported their use in biomedicine, tissue engineering as well as in diverse modern technologies. The goal of this study was the screening of new species of the order Verongiida to find another renewable source of naturally prefabricated 3D chitinous scaffolds. Special attention was paid to demosponge species, which could be farmed on large scale using marine aquaculture methods. In this study, the demosponge Pseudoceratina arabica collected in the coastal waters of the Egyptian Red Sea was examined as a potential source of chitin for the first time. Various bioanalytical tools including scanning electron microscopy (SEM), fluorescence microscopy, FTIR analysis, Calcofluor white staining, electrospray ionization mass spectrometry (ESI-MS), as well as a chitinase digestion assay were successfully used to confirm the discovery of α-chitin within the skeleton of P. arabica. The current finding should make an important contribution to the field of application of this verongiid sponge as a novel renewable source of biologically-active metabolites and chitin, which are important for development of the blue biotechnology especially in marine oriented biomedicine.


Assuntos
Quitina/química , Poríferos/química , Animais , Quitina/isolamento & purificação , Quitina/ultraestrutura , Oceano Índico , Microscopia Eletrônica de Varredura/métodos , Poríferos/ultraestrutura , Espectrometria de Massas por Ionização por Electrospray , Espectroscopia de Infravermelho com Transformada de Fourier
3.
J Morphol ; 279(12): 1872-1886, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30506663

RESUMO

The main characteristic of sponges (Porifera) is the presence of the aquiferous system-a system formed by canals and choanocyte chambers, in which the sponges carry out most of their physiological functions. Despite of the importance for the biology of the group, the knowledge about this structure is still incipient, even when morphological investigations are taken in account. Here, we investigated the anatomy and ultrastructure of the tropical demosponge Cladocroce caelum (Haplosclerida, Demospongiae) using light and electron microscopy. In the studied region, specimens of this species were repent or repent-branched, possessing one to several oscula. A uniform and reduced atrium was found just below each osculum. There was a thin ectosome and the choanosome presented meager mesohyl, but a high number of choanocyte chambers. The choanocyte chambers were rounded, and, as in other haplosclerids, they are found separated from the mesohyl by endopinacocytes, "hanging" in the inhalant canals. Even though the utility of the general organization of the aquiferous system has been advocated as a possible tool to understand the phylogeny of the group, we found that these characters might not be as useful as expected. The size of the particles ingested by the sponge and the amount of bacteria to sustain their bodies are discussed. In addition, we found that the density of choanocyte chambers was reduced when the specimens were carrying out the spermatogenesis, indicating that the reproduction may impair the filtering activity of the sponge. Our findings consist in a first step to better comprehend the physiology, development, and adaptation to the environmental conditions where the species is found.


Assuntos
Poríferos/anatomia & histologia , Poríferos/ultraestrutura , Clima Tropical , Adaptação Fisiológica , Animais , Filogenia , Poríferos/citologia
4.
J Biol Chem ; 293(30): 11674-11686, 2018 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-29880641

RESUMO

The evolution of cell-adhesion mechanisms in animals facilitated the assembly of organized multicellular tissues. Studies in traditional animal models have revealed two predominant adhesion structures, the adherens junction (AJ) and focal adhesions (FAs), which are involved in the attachment of neighboring cells to each other and to the secreted extracellular matrix (ECM), respectively. The AJ (containing cadherins and catenins) and FAs (comprising integrins, talin, and paxillin) differ in protein composition, but both junctions contain the actin-binding protein vinculin. The near ubiquity of these structures in animals suggests that AJ and FAs evolved early, possibly coincident with multicellularity. However, a challenge to this perspective is that previous studies of sponges-a divergent animal lineage-indicate that their tissues are organized primarily by an alternative, sponge-specific cell-adhesion mechanism called "aggregation factor." In this study, we examined the structure, biochemical properties, and tissue localization of a vinculin ortholog in the sponge Oscarella pearsei (Op). Our results indicate that Op vinculin localizes to both cell-cell and cell-ECM contacts and has biochemical and structural properties similar to those of vertebrate vinculin. We propose that Op vinculin played a role in cell adhesion and tissue organization in the last common ancestor of sponges and other animals. These findings provide compelling evidence that sponge tissues are indeed organized like epithelia in other animals and support the notion that AJ- and FA-like structures extend to the earliest periods of animal evolution.


Assuntos
Poríferos/citologia , Vinculina/metabolismo , Actinas/análise , Actinas/metabolismo , Animais , Adesão Celular , Adesões Focais/metabolismo , Modelos Moleculares , Poríferos/metabolismo , Poríferos/ultraestrutura , Ligação Proteica , Conformação Proteica , Pseudópodes/metabolismo , Pseudópodes/ultraestrutura , Talina/análise , Talina/metabolismo , Vinculina/análise
5.
Mar Drugs ; 16(3)2018 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-29510493

RESUMO

The biosynthesis, structural diversity, and functionality of collagens of sponge origin are still paradigms and causes of scientific controversy. This review has the ambitious goal of providing thorough and comprehensive coverage of poriferan collagens as a multifaceted topic with intriguing hypotheses and numerous challenging open questions. The structural diversity, chemistry, and biochemistry of collagens in sponges are analyzed and discussed here. Special attention is paid to spongins, collagen IV-related proteins, fibrillar collagens from demosponges, and collagens from glass sponge skeletal structures. The review also focuses on prospects and trends in applications of sponge collagens for technology, materials science and biomedicine.


Assuntos
Produtos Biológicos/química , Colágeno/química , Poríferos/metabolismo , Tecidos Suporte , Animais , Produtos Biológicos/uso terapêutico , Colágeno/biossíntese , Colágeno/ultraestrutura , Microscopia Eletrônica de Varredura , Poríferos/ultraestrutura
6.
Proc Biol Sci ; 285(1870)2018 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-29321296

RESUMO

The ability to encrust in order to secure and maintain growth on a substrate is a key competitive innovation in benthic metazoans. Here we describe the substrate growth dynamics, mode of biomineralization and possible affinity of Namapoikia rietoogensis, a large (up to 1 m), robustly skeletal, and modular Ediacaran metazoan which encrusted the walls of synsedimentary fissures within microbial-metazoan reefs. Namapoikia formed laminar or domal morphologies with an internal structure of open tubules and transverse elements, and had a very plastic, non-deterministic growth form which could encrust both fully lithified surfaces as well as living microbial substrates, the latter via modified skeletal holdfasts. Namapoikia shows complex growth interactions and substrate competition with contemporary living microbialites and thrombolites, including the production of plate-like dissepiments in response to microbial overgrowth which served to elevate soft tissue above the microbial surface. Namapoikia could also recover from partial mortality due to microbial fouling. We infer initial skeletal growth to have propagated via the rapid formation of an organic scaffold via a basal pinacoderm prior to calcification. This is likely an ancient mode of biomineralization with similarities to the living calcified demosponge Vaceletia. Namapoikia also shows inferred skeletal growth banding which, combined with its large size, implies notable individual longevity. In sum, Namapoikia was a large, relatively long-lived Ediacaran clonal skeletal metazoan that propagated via an organic scaffold prior to calcification, enabling rapid, effective and dynamic substrate occupation and competition in cryptic reef settings. The open tubular internal structure, highly flexible, non-deterministic skeletal organization, and inferred style of biomineralization of Namapoikia places probable affinity within total-group poriferans.


Assuntos
Biomineralização , Fósseis , Poríferos/crescimento & desenvolvimento , Animais , Recifes de Corais , Fósseis/microbiologia , Fósseis/ultraestrutura , Sedimentos Geológicos , Poríferos/microbiologia , Poríferos/ultraestrutura
7.
Spectrochim Acta A Mol Biomol Spectrosc ; 192: 368-377, 2018 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-29179087

RESUMO

The Demospongiae is the largest Class in the phylum Porifera (sponges). Most sponge species in the Class Demospongiae have a skeleton of siliceous spicules and/or protein spongin or both. The first aim of this study was to perform the morphological and structural characterization of the siliceous spicules of four species belonging to Class Demospongiae (Suberites domuncula, Axinella polypoides, Axinella damicornis and Agelas oroides) collected around Gökçeada Island-Turkey (Northern Aegean Sea). The characterizations were carried out using a combination of Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM/EDX), Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Small Angle X-ray Scattering (SAXS) techniques. The sponge Chondrosia reniformis (Porifera, Demospongiae) lacks a structural skeleton of spicules or the spongin. It consists mainly of a collagenous tissue. The collagen with sponge origin is an important source in biomedical and pharmaceutical applications. The second aim of this study was to provide more information on the molecular structure of collagen of outer (ectosome) and inner (choanosome) regions of the Chondrosia reniformis using ATR-FTIR spectroscopy. Hierarchical clustering analysis (HCA) was also used for the discrimination of ATR-FTIR spectra of species.


Assuntos
Ilhas , Oceanos e Mares , Poríferos/ultraestrutura , Animais , Análise por Conglomerados , Filogenia , Poríferos/anatomia & histologia , Espalhamento a Baixo Ângulo , Dióxido de Silício/química , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
8.
Sci Adv ; 3(10): eaao2047, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-29057327

RESUMO

Demospongiae is a class of marine sponges that mineralize skeletal elements, the glass spicules, made of amorphous silica. The spicules exhibit a diversity of highly regular three-dimensional branched morphologies that are a paradigm example of symmetry in biological systems. Current glass shaping technology requires treatment at high temperatures. In this context, the mechanism by which glass architectures are formed by living organisms remains a mystery. We uncover the principles of spicule morphogenesis. During spicule formation, the process of silica deposition is templated by an organic filament. It is composed of enzymatically active proteins arranged in a mesoscopic hexagonal crystal-like structure. In analogy to synthetic inorganic nanocrystals that show high spatial regularity, we demonstrate that the branching of the filament follows specific crystallographic directions of the protein lattice. In correlation with the symmetry of the lattice, filament branching determines the highly regular morphology of the spicules on the macroscale.


Assuntos
Vidro/análise , Animais , Imageamento Tridimensional , Microscopia Eletrônica de Varredura , Morfogênese , Poríferos/ultraestrutura , Dióxido de Silício/análise , Dióxido de Silício/química , Difração de Raios X
9.
Sci Rep ; 7: 43674, 2017 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-28262822

RESUMO

From an evolutionary point of view, sponges are ideal targets to study marine symbioses as they are the most ancient living metazoans and harbour highly diverse microbial communities. A recently discovered association between the sponge Hemimycale columella and an intracellular bacterium that generates large amounts of calcite spherules has prompted speculation on the possible role of intracellular bacteria in the evolution of the skeleton in early animals. To gain insight into this purportedly ancestral symbiosis, we investigated the presence of symbiotic bacteria in Mediterranean and Caribbean sponges. We found four new calcibacteria OTUs belonging to the SAR116 in two orders (Poecilosclerida and Clionaida) and three families of Demospongiae, two additional OTUs in cnidarians and one more in seawater (at 98.5% similarity). Using a calcibacteria targeted probe and CARD-FISH, we also found calcibacteria in Spirophorida and Suberitida and proved that the calcifying bacteria accumulated at the sponge periphery, forming a skeletal cortex, analogous to that of siliceous microscleres in other demosponges. Bacteria-mediated skeletonization is spread in a range of phylogenetically distant species and thus the purported implication of bacteria in skeleton formation and evolution of early animals gains relevance.


Assuntos
Bactérias , Calcificação Fisiológica , Poríferos/microbiologia , Água do Mar/microbiologia , Simbiose , Animais , Bactérias/classificação , Bactérias/genética , Bactérias/ultraestrutura , Biodiversidade , Hibridização in Situ Fluorescente , Oceanos e Mares , Filogenia , Poríferos/ultraestrutura , RNA Ribossômico 16S
10.
J Struct Biol ; 198(3): 186-195, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28323140

RESUMO

The skeletal system of Demospongiae consists of siliceous spicules, which are composed of an axial channel containing an organic axial filament (AF) surrounded by a compact layer of hydrated amorphous silica. Here we report the ultrastructural investigations of the AF of siliceous spicules from two Demospongiae: Suberites domuncula and Tethya aurantium. Electron microscopy, electron diffraction and elemental mapping analyses on both longitudinal and transversal cross-sections yield that spicules's AF consist of a three-dimensional crystal lattice of six-fold symmetry. Its structure, which is the result of a biological growth process, is a crystalline assembly characterized by a lattice of organic cages (periodicity in the range of 6nm) filled with enzymatically-produced silica. In general, the six-fold lattice symmetry is reflected by the morphology of the AF, which is characterized by six-fold facets. This seems to be the result of a lattice energy minimization process similar to the situation found during the growth of inorganic crystals. Our structural exploitation of three-dimensional organic lattices generated by biological systems is expected to contribute for explaining the relation between axial filament's ultrastructure and spicule's ultimate morphology.


Assuntos
Poríferos/anatomia & histologia , Dióxido de Silício/química , Animais , Cristalização , Análise de Elementos Finitos , Microscopia Eletrônica , Microscopia Eletrônica de Transmissão , Morfogênese , Compostos Orgânicos/química , Poríferos/química , Poríferos/crescimento & desenvolvimento , Poríferos/ultraestrutura , Suberites/ultraestrutura
11.
J Exp Biol ; 220(Pt 6): 995-1007, 2017 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-28011822

RESUMO

Sponges (Porifera) are abundant in most marine and freshwater ecosystems, and as suspension feeders they play a crucial role in filtering the water column. Their active pumping enables them to filter up to 900 times their body volume of water per hour, recycling nutrients and coupling a pelagic food supply with benthic communities. Despite the ecological importance of sponge filter feeding, little is known about how sponges control the water flow through their canal system or how much energy it costs to filter the water. Sponges have long been considered textbook examples of animals that use current-induced flow. We provide evidence that suggests that some species of demosponge do not use current-induced flow; rather, they respond behaviourally to increased ambient currents by reducing the volume of water filtered. Using a morphometric model of the canal system, we also show that filter feeding may be more energetically costly than previously thought. Measurements of volumetric flow rates and oxygen removal in five species of demosponge show that pumping rates are variable within and between species, with the more oxygen consumed the greater the volume filtered. Together, these data suggest that sponges have active control over the volume of water they process, which may be an adaptation to reduce the energetic cost of filtration in times of high stress.


Assuntos
Poríferos/fisiologia , Poríferos/ultraestrutura , Água/metabolismo , Animais , Comportamento Animal , Ecossistema , Metabolismo Energético , Filtração , Oxigênio/metabolismo , Consumo de Oxigênio , Poríferos/anatomia & histologia
12.
Zootaxa ; 4208(4): zootaxa.4208.4.3, 2016 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-28006812

RESUMO

We used both morphological and genetic approaches to investigate and to describe a new Mediterranean sponge species of the genus Protosuberites from the estuarine-anchialine Bue Marino Cave of Sardinia (Tyrrhenian Sea). The morphotraits of the specimens were compared versus congeneric species with the strongest affinities, covering the genus geographic range worldwide. Protosuberites mereui sp. nov. is light yellow, thinly encrusting, devoid of any special ectosomal skeleton, with spicular complement of tylostyles of three size classes, single or arranged in bundles/tufts, with round to suboval heads. The new species is characterized by an exclusive diagnostic trait recorded for any cave-dwelling Protosuberites i.e. suboval and basally plated resting bodies with a foraminal aperture ornate by a collar. Resting bodies were found in the basal spongin plate firmly adhering to the substratum singly or in small groups. Also the rare, small tylostyles with a sinuous shaft and a typical mushroom-like head were never recorded in the Western Mediterranean and Atlantic species of the genus. The phylogenetic reconstruction using maximum likelihood (ML) and Bayesian Inference (BI) analyses (COI, 18S rRNA, and 28S rRNA) recovered a robustly supported sister relationship between the Mediterranean P. mereui sp. nov. and Protosuberites sp. 'Panama' from the Eastern Pacific Ocean. The genetic distances based on COI sequences between all compared Protosuberites species were always higher than 2%, a value sufficient to confirm that P. mereui sp. nov. is a distinct species within the genus. Morphological and genetic analyses confirm unanimously P. mereui sp. nov. as a new species. Our results contribute to the assessment of biodiversity in anchialine/estuarine caves and increase data on sponge adaptive strategies in these extreme ecosystems.


Assuntos
Poríferos/classificação , Poríferos/genética , Animais , Cavernas , Complexo IV da Cadeia de Transporte de Elétrons/genética , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Itália , Microscopia Eletrônica de Varredura , Filogenia , Poríferos/anatomia & histologia , Poríferos/ultraestrutura , RNA Ribossômico 18S/genética , RNA Ribossômico 18S/metabolismo , RNA Ribossômico 28S/genética , RNA Ribossômico 28S/metabolismo , Águas Salinas , Análise de Sequência de DNA
13.
Zootaxa ; 4173(6): 501-529, 2016 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-27811812

RESUMO

We present additional taxonomic descriptions, with Scanning Electron Microscopy (SEM) illustrations, field observations documented by colour photographs, and notes on habitats and ecology of Corvospongilla ultima (Annandale), Eunapius crassissimus (Annandale), Stratospongilla bombayensis (Carter), S. gravelyi (Annandale) and S. indica (Annandale) from recent sponge collections made in western Maharashtra, India. Stratospongilla gravelyi is rediscovered after a century, and along with it, C. ultima and S. indica are illustrated with SEM images for the first time, unequivocally differentiating these two species. Additional taxonomic, ecological data and illustrations of Corvospongilla lapidosa (Annandale), Dosilia plumosa (Carter), Ephydatia meyeni (Carter), Eunapius carteri (Bowerbank) and Radiospongilla cerebellata (Bowerbank) are also provided to supplement the previously published SEM illustrations. All ten spongillid species treated here were originally described from India and three of them are known to be endemic to the Indian region. Present study is the first re-examination of these Indian spongillid species using SEM, providing greater resolution of their important taxonomic characters and careful documentation of their habitats.


Assuntos
Ecossistema , Poríferos/anatomia & histologia , Poríferos/classificação , Animais , Água Doce , Índia , Microscopia Eletrônica de Varredura , Poríferos/ultraestrutura , Especificidade da Espécie
14.
Zootaxa ; 4144(3): 365-82, 2016 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-27470862

RESUMO

Two new species, Hamacantha (Vomerula) cassanoi n. sp. and Prosuberites salgadoi n. sp., are described from the eastern Gulf of Alaska in the North Pacific Ocean. These are the first records of the genera Hamacantha and Prosuberites from Alaska. We also report two geographic range extensions for the region. Geodia japonica Sollas, 1888 was previously known only from Japan and is now recorded from the Gulf of Alaska. We also document the first record of Rhizaxinella cervicornis Thiele, 1898 from the Gulf of Alaska. Our comprehensive inventory of the sponge fauna of the Gulf of Alaska confirms the presence of 52 taxa with an additional 38 taxa suspected of occurring in the region. This is a much lower number of species than that recorded from neighbouring regions like the Aleutian Islands and British Columbia.


Assuntos
Poríferos/classificação , Alaska , Distribuição Animal/fisiologia , Animais , Oceano Pacífico , Poríferos/fisiologia , Poríferos/ultraestrutura , Especificidade da Espécie
15.
Biol Bull ; 230(3): 220-32, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27365417

RESUMO

The sponge Chondrosia reniformis selectively engulfs siliceous particles that, when in crystalline form, become quickly dissolved in its ectosome. The molecular mechanism, identity, and physiological significance of the cells involved in this process are not completely understood. In the present study, we applied light and electronic microscopic techniques to show how the quartz particles in C. reniformis are enveloped through collagen fibers and host cells near the surface of these organisms. As various aquaporins from bacteria, animals, and plants bidirectionally conduct metalloids-including silicon ions--through the cell membrane, the presence and potential involvement of aquaporins in quartz dissolution in C. reniformis have been investigated. An aquaporin-like transcript (CrAQP) was isolated according to the transcriptome sequencing results in C. reniformis The full-length CrAQP cDNA is 907 nucleotides long, with a 795-base pair (bp), open reading frame encoding a protein of 265 amino acids, a 29-bp, 5'-non-coding region, and a 83-bp, 3'-untranslated region. The Bayesian phylogenetic inference suggests that CrAqp is closely related to the Aqp8L grade, which is also implicated in H2O2 transport. Quantification of CrAQP mRNA through qPCR indicated that the transcript level was higher in the ectosome than in the choanosome. Immunofluorescence of a mammalian AQP8 in C. reniformis showed positivity in some cells near the quartz particles, a finding that may support the initial hypothesis of the potential involvement of CrAQP in quartz erosion. However, the features of the primary structure of this protein offer a new viewpoint about the functional role of these molecules in this process: that CrAQP may be involved in the permeation of H2O2 released during silica erosion.


Assuntos
Aquaporinas/metabolismo , Poríferos/metabolismo , Poríferos/ultraestrutura , Sequência de Aminoácidos , Animais , Aquaporinas/química , Aquaporinas/genética , Aquaporinas/isolamento & purificação , Sequência de Bases , Teorema de Bayes , DNA Complementar , Peróxido de Hidrogênio/metabolismo , Filogenia , Poríferos/classificação , Poríferos/genética
16.
J Morphol ; 277(7): 925-34, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27091517

RESUMO

Every large clade of Eukarya has its own pattern of kinetid (flagellar apparatus) structure, which is stable and specific within the group, thereby being a good phylogenetic marker. The kinetid structure of sponge choanocytes might be a candidate for such marker for the phylogeny of Porifera. Kinetids of two heteroscleromorphs, Halichondria sp. (Suberitida) and Crellomima imparidens (Poecilosclerida), have been investigated here for the first time, and a reconstruction of the kinetid for each species is provided. The kinetids of both species comprise a flagellar kinetosome with a nuclear fibrillar root, a basal foot and satellite producing microtubules; a centriole is absent. Good resolution images reveal a new thin structure, the axial granule, in the flagellar transition zone which might be present in other sponges. The comparison of kinetids in investigated sponges revealed three types of kinetid in Demospongiae, and their distribution in the taxon has been shown on a molecular phylogenetic tree. Kinetid characters of the common ancestor of Demospongiae are discussed. J. Morphol. 277:925-934, 2016. © 2016 Wiley Periodicals, Inc.


Assuntos
Evolução Biológica , Centríolos/ultraestrutura , Microtúbulos/ultraestrutura , Poríferos/ultraestrutura , Animais , Filogenia , Poríferos/classificação
17.
J Exp Zool A Ecol Genet Physiol ; 325(2): 158-77, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26863993

RESUMO

Sponges (phylum Porifera) are one of the most ancient extant multicellular animals and can provide valuable insights into origin and early evolution of Metazoa. High plasticity of cell differentiations and anatomical structure is characteristic feature of sponges. Present study deals with sponge cell reaggregation after dissociation as the most outstanding case of sponge plasticity. Dynamic of cell reaggregation and structure of multicellular aggregates of three demosponge species (Halichondria panicea (Pallas, 1766), Haliclona aquaeductus (Sсhmidt, 1862), and Halisarca dujardinii Johnston, 1842) were studied. Sponge tissue dissociation was performed mechanically. Resulting cell suspensions were cultured at 8-10°C for at least 5 days. Structure of multicellular aggregates was studied by light, transmission and scanning electron microscopy. Studied species share common stages of cell reaggregation-primary multicellular aggregates, early-stage primmorphs and primmorphs, but the rate of reaggregation varies considerably among species. Only cells of H. dujardinii are able to reconstruct functional and viable sponge after primmorphs formation. Sponge reconstruction in this species occurs due to active cell locomotion. Development of H. aquaeductus and H. panicea cells ceases at the stages of early primmorphs and primmorphs, respectively. Development of aggregates of these species is most likely arrested due to immobility of the majority of cells inside them. However, the inability of certain sponge species to reconstruct functional and viable individuals during cell reaggregation may be not a permanent species-specific characteristic, but depends on various factors, including the stage of the life cycle and experimental conditions.


Assuntos
Morfogênese , Poríferos/citologia , Poríferos/crescimento & desenvolvimento , Animais , Agregação Celular , Movimento Celular , Estruturas Celulares/citologia , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Poríferos/ultraestrutura , Especificidade da Espécie
18.
J Struct Biol ; 194(1): 124-8, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26853498

RESUMO

Sponge glass spicules have solicited great interest due to their mechanical and optical properties. Herein we use ptychographic nanotomography to obtain detailed insights into the internal structure of an anchor spicule from the Venus flower basket. The obtained dataset has 90nm resolution in 3D and provides quantitative determination of the electron density. The data reveal significant variations in electron density across the spicule. The central organic filament is found to be slightly but significantly displaced from the spicule central axis. Analysis of the electron density affords an estimate of a protein volume fraction in the organic filament of about 70%. In the highly mineralized part of the spicule, the electron density is seen to display circular symmetry and be neigh independent of position along the spicule long axis. Variations in the electron density beyond those included in current models of spicule mechanics are observed.


Assuntos
Vidro/química , Poríferos/química , Dióxido de Silício/química , Microtomografia por Raio-X/métodos , Animais , Diagnóstico por Imagem/métodos , Imageamento Tridimensional/métodos , Microscopia Eletrônica de Varredura , Poríferos/ultraestrutura
19.
J Biol Chem ; 291(18): 9425-37, 2016 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-26917726

RESUMO

Early metazoans had to evolve the first cell adhesion mechanism addressed to maintain a distinctive multicellular morphology. As the oldest extant animals, sponges are good candidates for possessing remnants of the molecules responsible for this crucial evolutionary innovation. Cell adhesion in sponges is mediated by the calcium-dependent multivalent self-interactions of sulfated polysaccharides components of extracellular membrane-bound proteoglycans, namely aggregation factors. Here, we used atomic force microscopy to demonstrate that the aggregation factor of the sponge Desmapsamma anchorata has a circular supramolecular structure and that it thus belongs to the spongican family. Its sulfated polysaccharide units, which were characterized via nuclear magnetic resonance analysis, consist preponderantly of a central backbone composed of 3-α-Glc1 units partially sulfated at 2- and 4-positions and branches of Pyr(4,6)α-Gal1→3-α-Fuc2(SO3)1→3-α-Glc4(SO3)1→3-α-Glc→4-linked to the central α-Glc units. Single-molecule force measurements of self-binding forces of this sulfated polysaccharide and their chemically desulfated and carboxyl-reduced derivatives revealed that the sulfate epitopes and extracellular calcium are essential for providing the strength and stability necessary to sustain cell adhesion in sponges. We further discuss these findings within the framework of the role of molecular structures in the early evolution of metazoans.


Assuntos
Evolução Biológica , Cálcio/química , Polissacarídeos/química , Poríferos/química , Sulfatos/química , Animais , Cálcio/metabolismo , Microscopia de Força Atômica , Polissacarídeos/metabolismo , Polissacarídeos/ultraestrutura , Poríferos/metabolismo , Poríferos/ultraestrutura , Sulfatos/metabolismo
20.
J Struct Biol ; 194(1): 29-37, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26821342

RESUMO

Siliceous sponges are the most primitive multicellular animals whose skeleton consists of spicules - needle-like constructions from silicon dioxide surrounding organic axial filaments. Mechanisms of spicule formation have been intensively studied due to the high ecological importance of sponges and their interest to materials science. Light and electron microscopy are not appropriate enough to display the process from silicon-enriched cells to mature spicules because of composite structure of the sponge tissues. In this article, spiculogenesis in the siliceous sponge has been studied for the first time with the use of fluorescent microscopy. Fluorescent vital dye NBD-N2 was applied to stain growing siliceous structures in the sponge and primmorph cell system. The main stages of spicule growth in the fresh-water sponge Lubomirskia baicalensis (Pallas, 1773) were visualized: silicon accumulation in sclerocytes; formation of an organic filament protruding from the cell; further elongation of the filament and growth of the spicule in a spindle-like form with enlargement in the center; merger with new sclerocytes and formation of the mature spicule. Fluorescent microscopy combined with SEM allows us to overcome the virtual differentiation between intra- and extracellular mechanisms of spicule growth. The growing spicule can capture silicic acid from the extracellular space and merge with new silicon-enriched cells. Visualization of the growing spicules with the fluorescent dye allows us to monitor sponge viability in ecological or toxicological experiments and to apply genomic, proteomic and biochemical techniques.


Assuntos
Corantes Fluorescentes/química , Poríferos/química , Poríferos/citologia , Dióxido de Silício/química , 4-Cloro-7-nitrobenzofurazano/análogos & derivados , 4-Cloro-7-nitrobenzofurazano/química , Animais , Citoesqueleto/química , Citoesqueleto/ultraestrutura , Lagos , Microscopia Eletrônica de Varredura , Microscopia de Fluorescência , Poríferos/ultraestrutura , Propilaminas/química
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