Sample records for annelid pomatoceros lamarckii

  1. An EST screen from the annelid Pomatoceros lamarckii reveals patterns of gene loss and gain in animals

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    Chen Wei-Chung


    Full Text Available Abstract Background Since the drastic reorganisation of the phylogeny of the animal kingdom into three major clades of bilaterians; Ecdysozoa, Lophotrochozoa and Deuterostomia, it became glaringly obvious that the selection of model systems with extensive molecular resources was heavily biased towards only two of these three clades, namely the Ecdysozoa and Deuterostomia. Increasing efforts have been put towards redressing this imbalance in recent years, and one of the principal phyla in the vanguard of this endeavour is the Annelida. Results In the context of this effort we here report our characterisation of an Expressed Sequence Tag (EST screen in the serpulid annelid, Pomatoceros lamarckii. We have sequenced over 5,000 ESTs which consolidate into over 2,000 sequences (clusters and singletons. These sequences are used to build phylogenetic trees to estimate relative branch lengths amongst different taxa and, by comparison to genomic data from other animals, patterns of gene retention and loss are deduced. Conclusion The molecular phylogenetic trees including the P. lamarckii sequences extend early observations that polychaetes tend to have relatively short branches in such trees, and hence are useful taxa with which to reconstruct gene family evolution. Also, with the availability of lophotrochozoan data such as that of P. lamarckii, it is now possible to make much more accurate reconstructions of the gene complement of the ancestor of the bilaterians than was previously possible from comparisons of ecdysozoan and deuterostome genomes to non-bilaterian outgroups. It is clear that the traditional molecular model systems for protostomes (e.g. Drosophila melanogaster and Caenorhabditis elegans, which are restricted to the Ecdysozoa, have undergone extensive gene loss during evolution. These ecdysozoan systems, in terms of gene content, are thus more derived from the bilaterian ancestral condition than lophotrochozoan systems like the polychaetes

  2. The development of the larval nervous system, musculature and ciliary bands of Pomatoceros lamarckii (Annelida: heterochrony in polychaetes

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    Shimeld Sebastian M


    Full Text Available Abstract Background To understand the evolution of animals it is essential to have taxon sampling across a representative spread of the animal kingdom. With the recent rearrangement of most of the Bilateria into three major clades (Ecdysozoa, Lophotrochozoa and Deuterostomia it has become clear that the Lophotrochozoa are relatively poorly represented in our knowledge of animal development, compared to the Ecdysozoa and Deuterostomia. We aim to contribute towards redressing this balance with data on the development of the muscular, nervous and ciliary systems of the annelid Pomatoceros lamarckii (Serpulidae. We compare our data with other lophotrochozoans. Results P. lamarckii develops locomotory and feeding structures that enable it to become a swimming, planktotrophic larva within 24 hours. Formation of the trochophore includes development of a prototroch, metatroch and neurotroch, development of apical and posterior nervous elements at similar times, and development of musculature around the ciliary bands and digestive tract prior to development of any body wall muscles. The adult nervous and muscular systems are essentially preformed in the late larva. Interestingly, the muscular systems of the larvae and juvenile worms do not include the circular muscles of the body wall, which are considered to be plesiomorphic for annelids, although the possibility that circular muscles develop after these stages cannot be ruled out at this point. Conclusion A comparison between polychaetes shows variability in the timing (heterochrony of development of body wall muscles and elements of the nervous system. These heterochronies are one route for evolution of different life history strategies, such as adaptations to feeding requirements.

  3. Annelid Distal-less/Dlx duplications reveal varied post-duplication fates

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    Korchagina Natalia


    Full Text Available Abstract Background Dlx (Distal-less genes have various developmental roles and are widespread throughout the animal kingdom, usually occurring as single copy genes in non-chordates and as multiple copies in most chordate genomes. While the genomic arrangement and function of these genes is well known in vertebrates and arthropods, information about Dlx genes in other organisms is scarce. We investigate the presence of Dlx genes in several annelid species and examine Dlx gene expression in the polychaete Pomatoceros lamarckii. Results Two Dlx genes are present in P. lamarckii, Capitella teleta and Helobdella robusta. The C. teleta Dlx genes are closely linked in an inverted tail-to-tail orientation, reminiscent of the arrangement of vertebrate Dlx pairs, and gene conversion appears to have had a role in their evolution. The H. robusta Dlx genes, however, are not on the same genomic scaffold and display divergent sequences, while, if the P. lamarckii genes are linked in a tail-to-tail orientation they are a minimum of 41 kilobases apart and show no sign of gene conversion. No expression in P. lamarckii appendage development has been observed, which conflicts with the supposed conserved role of these genes in animal appendage development. These Dlx duplications do not appear to be annelid-wide, as the polychaete Platynereis dumerilii likely possesses only one Dlx gene. Conclusions On the basis of the currently accepted annelid phylogeny, we hypothesise that one Dlx duplication occurred in the annelid lineage after the divergence of P. dumerilii from the other lineages and these duplicates then had varied evolutionary fates in different species. We also propose that the ancestral role of Dlx genes is not related to appendage development.

  4. Antimicrobial peptides in annelids

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    A Tasiemski


    Full Text Available Gene encoded antimicrobial peptides (AMPs are widely distributed among living organisms including plants, invertebrates and vertebrates. They constitute important effectors of the innate immune response by exerting multiple roles as mediators of inflammation with impact on epithelial and inflammatory cells influencing diverse processes such as cytokine release, cell proliferation, angiogenesis, wound healing, chemotaxis and immune induction. In invertebrates, most of the data describe the characterization and/or the function of AMPs in the numerically and economically most representative group which are arthropods. Annelids are among the first coelomates and are therefore of special phylogenetic interest. Compared to other invertebrate groups, data on annelid’s immunity reveal heavier emphasis on the cellular than on the humoral response suggesting that immune defense of annelids seems to be principally developed as cellular immunity.This paper gives an overview of the variety of AMPs identified in the three classes of annelids, i.e. polychaetes, oligochaetes and achaetes. Their functions, when they have been studied, in the humoral or cellular response of annelids are also mentioned.

  5. On some Polychaetous Annelids from Curaçao

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    Horst, R.


    Though we know already a rather large number of Polychaetous Annelids from the Caribbean Sea, hitherto, as far as I know, no Annelids have been described from the coast of the island Curaçao and I therefore was very glad, that my colleague Dr. VAN DER HORST kindly placed in my hands for identificati

  6. Hedgehog signaling regulates segment formation in the annelid Platynereis


    Dray, Nicolas; Tessmar-Raible, Kristin; Le Gouar, Martine; Vibert, Laura; Christodoulou, Foteini; Schipany, Katharina; Guillou, Aurélien; Zantke, Juliane; Snyman, Heidi; Béhague, Julien; Vervoort, Michel; Arendt, Detlev; Balavoine, Guillaume


    Annelids and arthropods share a similar segmented organization of the body whose evolutionary origin remains unclear. The Hedgehog signaling pathway, prominent in arthropod embryonic segment patterning has not been shown to have a similar function outside arthropods. We show that the ligand Hedgehog, the receptor Patched, and the transcription factor Gli are all expressed in striped patterns prior to morphological segment appearance in the annelid Platynereis dumerilii. Treatments with small ...

  7. Annelids in evolutionary developmental biology and comparative genomics

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    Mcdougall C.


    Full Text Available Annelids have had a long history in comparative embryology and morphology, which has helped to establish them in zoology textbooks as an ideal system to understand the evolution of the typical triploblastic, coelomate, protostome condition. In recent years there has been a relative upsurge in embryological data, particularly with regard to the expression and function of developmental control genes. Polychaetes, as well as other annelids such as the parasitic leech, are now also entering the age of comparative genomics. All of this comparative data has had an important impact on our views of the ancestral conditions at various levels of the animal phylogeny, including the bilaterian ancestor and the nature of the annelid ancestor. Here we review some of the recent advances made in annelid comparative development and genomics, revealing a hitherto unsuspected level of complexity in these ancestors. It is also apparent that the transition to a parasitic lifestyle leads to, or requires, extensive modifications and derivations at both the genomic and embryological levels.

  8. Is Diurodrilus an annelid?

    DEFF Research Database (Denmark)

    Worsaae, Katrine; Rouse, Greg W.


    segmentation. We assessed the systematic position of Diurodrilus among other protostome animals via light microscopy, confocal laser scanning microscopy, and transmission electron microscopy studies of anatomy, focusing on musculature, the nervous system, as well as molecular sequence data. We show that there...... is little morphological or molecular evidence to support a relationship with Dinophilidae or any other annelids. Diurodrilus has some similarities to Micrognathozoa, though the latter shows complex jaws. On the basis of the configuration of the nervous system and the cuticle we regard Diurodrilus to......Interstitial marine meiofaunal worms of the genus Diurodrilus have always been considered part of Annelida, either as basal or derived, though generally with reference to Dinophilidae. New evidence shows that Diurodrilus has a unique anatomy, and lacks key annelid features, possibly even...

  9. Lower Cambrian polychaete from China sheds light on early annelid evolution


    Liu, Jianni; Ou, Qiang; Han, Jian; Li, Jinshu; Wu, Yichen; Jiao, Guoxiang; He, Tongjiang


    We herein report a fossilized polychaete annelid, Guanshanchaeta felicia gen. et sp. nov., from the Lower Cambrian Guanshan Biota (Cambrian Series 2, stage 4). The new taxon has a generalized polychaete morphology, with biramous parapodia (most of which preserve the evidence of chaetae), an inferred prostomium bearing a pair of appendages, and a bifid pygidium. G. felicia is the first unequivocal annelid reported from the Lower Cambrian of China. It represents one of the oldest annelids among...

  10. MicroRNAs resolve an apparent conflict between annelid systematics and their fossil record


    Sperling, Erik A.; Vinther, Jakob; Moy, Vanessa N.; Wheeler, Benjamin M.; Sémon, Marie; Briggs, Derek E.G; Peterson, Kevin J


    Both the monophyly and inter-relationships of the major annelid groups have remained uncertain, despite intensive research on both morphology and molecular sequences. Morphological cladistic analyses indicate that Annelida is monophyletic and consists of two monophyletic groups, the clitellates and polychaetes, whereas molecular phylogenetic analyses suggest that polychaetes are paraphyletic and that sipunculans are crown-group annelids. Both the monophyly of polychaetes and the placement of ...

  11. The impact of fossil data on annelid phylogeny inferred from discrete morphological characters. (United States)

    Parry, Luke A; Edgecombe, Gregory D; Eibye-Jacobsen, Danny; Vinther, Jakob


    As a result of their plastic body plan, the relationships of the annelid worms and even the taxonomic makeup of the phylum have long been contentious. Morphological cladistic analyses have typically recovered a monophyletic Polychaeta, with the simple-bodied forms assigned to an early-diverging clade or grade. This is in stark contrast to molecular trees, in which polychaetes are paraphyletic and include clitellates, echiurans and sipunculans. Cambrian stem group annelid body fossils are complex-bodied polychaetes that possess well-developed parapodia and paired head appendages (palps), suggesting that the root of annelids is misplaced in morphological trees. We present a reinvestigation of the morphology of key fossil taxa and include them in a comprehensive phylogenetic analysis of annelids. Analyses using probabilistic methods and both equal- and implied-weights parsimony recover paraphyletic polychaetes and support the conclusion that echiurans and clitellates are derived polychaetes. Morphological trees including fossils depict two main clades of crown-group annelids that are similar, but not identical, to Errantia and Sedentaria, the fundamental groupings in transcriptomic analyses. Removing fossils yields trees that are often less resolved and/or root the tree in greater conflict with molecular topologies. While there are many topological similarities between the analyses herein and recent phylogenomic hypotheses, differences include the exclusion of Sipuncula from Annelida and the taxa forming the deepest crown-group divergences. PMID:27581880

  12. Lower Cambrian polychaete from China sheds light on early annelid evolution (United States)

    Liu, Jianni; Ou, Qiang; Han, Jian; Li, Jinshu; Wu, Yichen; Jiao, Guoxiang; He, Tongjiang


    We herein report a fossilized polychaete annelid, Guanshanchaeta felicia gen. et sp. nov., from the Lower Cambrian Guanshan Biota (Cambrian Series 2, stage 4). The new taxon has a generalized polychaete morphology, with biramous parapodia (most of which preserve the evidence of chaetae), an inferred prostomium bearing a pair of appendages, and a bifid pygidium. G. felicia is the first unequivocal annelid reported from the Lower Cambrian of China. It represents one of the oldest annelids among those from other early Paleozoic Lagerstätten including Sirius Passet from Greenland (Vinther et al., Nature 451: 185-188, 2008) and Emu Bay from Kangaroo island (Parry et al., Palaeontology 57: 1091-1103, 2014), and adds to our increasing roll of present-day animal phyla recognized in the early Cambrian Guanshan Biota. This finding expands the panorama of the Cambrian `explosion' exemplified by the Guanshan Biota, suggesting the presence of many more fossil annelids in the Chengjiang Lagerstätte and the Kaili Biota. In addition, this new taxon increases our knowledge of early polychaete morphology, which suggests that polychaete annelids considerably diversified in the Cambrian.

  13. Gonad establishment during asexual reproduction in the annelid Pristina leidyi. (United States)

    Özpolat, B Duygu; Bely, Alexandra E


    Animals that can reproduce by both asexual agametic reproduction and sexual reproduction must transmit or re-establish their germ line post-embryonically. Although such a dual reproductive mode has evolved repeatedly among animals, how asexually produced individuals establish their germ line remains poorly understood in most groups. We investigated germ line development in the annelid Pristina leidyi, a species that typically reproduces asexually by paratomic fission, intercalating a new tail and head in the middle of the body followed by splitting. We found that in fissioning individuals, gonads occur in anterior segments in the anterior-most individual as well as in new heads forming within fission zones. Homologs of the germ line/multipotency genes piwi, vasa, and nanos are expressed in the gonads, as well as in proliferative tissues including the posterior growth zone, fission zone, and regeneration blastema. In fissioning animals, certain cells on the ventral nerve cord express a homolog of piwi, are abundant near fission zones, and sometimes make contact with gonads. Such cells are typically undetectable near the blastema and posterior growth zone. Time-lapse imaging provides direct evidence that cells on the ventral nerve cord migrate preferentially towards fission zones. Our findings indicate that gonads form routinely in fissioning individuals, that a population of piwi-positive cells on the ventral nerve cord is associated with fission and gonads, and that cells resembling these piwi-positive cells migrate along the ventral nerve cord. We suggest that the piwi-positive ventral cells are germ cells that transmit the germ line across asexually produced individuals via migration along the ventral nerve cord. PMID:26134407

  14. Isolation of a member of ets gene family in the polychaete annelid Perinereis cultrifera. (United States)

    Bocquet-Muchembled, B; Leroux, R; Chotteau-Lelièvre, A; Fontaine, F


    Numerous genes belonging to the ets gene family have been described for a few years. The founder of this family is the v-ets proto-oncogene, which is the viral counterpart of the chicken c-ets-1 proto-oncogene. Main research was carried out both on Vertebrates, Drosophila and the nematod Caenorhabditis elegans. Previously, two genes of this family named Nd ets and Nd erg, were isolated in the polychaete annelid Hediste (Nereis) diversicolor. Here we have described the isolation of one gene from the ets family in another polychaete annelid named Perinereis cultrifera. By polymerase chain reaction using degenerated primers, we have amplified an approximatively 515 pb genomic region encoding the ETS domain and another domain designed as "R" domain by Qi et al. (1992) and which can mediate transactivation. By using this method for isolating members of the ets gene family, we are going to realize a phylogenetic study of the phylum of polychaete annelids. PMID:11761710

  15. Soil-dwelling annelids during meadow restoration on arable soil using different restoration schemes

    Czech Academy of Sciences Publication Activity Database

    Schlaghamerský, J.; Pižl, Václav

    Xalapa : Instituto de Ecología, A.C, 2010. s. 117. [International Symposium on Earthworm Ecology /9./. 05.09.2010-10.09.2010, Xalapa] Institutional research plan: CEZ:AV0Z60660521 Keywords : soil -dwelling annelids * meadow restoration * arable soil Subject RIV: EH - Ecology, Behaviour

  16. Neuromuscular Structure, Evolution and Development in Meiofaunal Annelids with Special Focus on Dinophilus gyrociliatus (Dinophilidae)

    DEFF Research Database (Denmark)

    Kerbl, Alexandra

    BACKGROUND: The majority of annelid neuromorphological studies addresses macroscopic forms such as the well-studied Platynereis dumerilii; microscopic annelids are generally neglected. Several of these animals have remarkably smaller, compact brains composed of significantly fewer cells and having...... less complex sensory structures. Yet, very little is still known on how these small brains are organized to fulfil basic functions. This study addresses the structure, evolution and development of neuromuscular systems within two exclusively meiofaunal lineages Lobatocerebridae and Dinophilidae...

  17. Evolution and adaptation of marine annelids in interstitial and cave habitats

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    Martinez Garcia, Alejandro

    The origin of anchialine and marine cave fauna is still a highly debated topic in Evolutionary Biology. Restricted and disjunct distribution and uncertain affinities of some marine cave endemic lineages have favored their interpretation as living fossils, surviving the extinction of their coastal...... relatives in cave subterranean ecological refugia. Active colonization and ecological speciation to particular cave niches has been alternatively suggested, but the evaluation of that scenario is obscured by the dominance of crustaceans in anchialine habitats, ecologically similar out and inside caves. The...... main goal of this thesis is to explore the evolutionary processes behind colonization and adaptation to submarine cave ecosystems in the Atlantic Ocean using annelids as a model, mainly when they involved ancestrally interstitial forms. In order to do that, we studied selected lineages of annelids with...

  18. Novel Crystalline SiO2 Nanoparticles via Annelids Bioprocessing of Agro-Industrial Wastes (United States)

    Espíndola-Gonzalez, A.; Martínez-Hernández, A. L.; Angeles-Chávez, C.; Castaño, V. M.; Velasco-Santos, C.


    The synthesis of nanoparticles silica oxide from rice husk, sugar cane bagasse and coffee husk, by employing vermicompost with annelids ( Eisenia foetida) is reported. The product ( humus) is calcinated and extracted to recover the crystalline nanoparticles. X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and dynamic light scattering (DLS) show that the biotransformation allows creating specific crystalline phases, since equivalent particles synthesized without biotransformation are bigger and with different crystalline structure.

  19. The loss of the hemoglobin H2S-binding function in annelids from sulfide-free habitats reveals molecular adaptation driven by Darwinian positive selection


    Bailly, Xavier; Leroy, Riwanon; Carney, Susan; Collin, Olivier; Zal, Franck; Toulmond, André; Jollivet, Didier


    The hemoglobin of the deep-sea hydrothermal vent vestimentiferan Riftia pachyptila (annelid) is able to bind toxic hydrogen sulfide (H2S) to free cysteine residues and to transport it to fuel endosymbiotic sulfide-oxidising bacteria. The cysteine residues are conserved key amino acids in annelid globins living in sulfide-rich environments, but are absent in annelid globins from sulfide-free environments. Synonymous and nonsynonymous substitution analysis from two different sets of orthologous...

  20. The role of hydrostatic pressure on developmental stages of Pomatoceros lamarcki (Polychaeta: Serpulidae) exposed to water accommodated fractions of crude oil and positive genotoxins at simulated depths of 1000-3000 m

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    The effect of high hydrostatic pressures on the ecotoxicological profile of pollutants is an unexplored research area. Using Pomatoceros lamarcki as a surrogate organism for this eco-barotoxicological study, it was found that in a 48 h larval bioassay with water accommodated fractions (WAF) of crude oil of up to 15.1 mg L-1 (total hydrocarbon content) and hydrostatic pressures up to 300 bar (3000 m), an additive response was found (p -1) at 100 bar showed no effects on mitotic fidelity or cell division rate over the 1 bar treatment. However, embryo's treated with the clastogen mitomycin-c at 100 bar exhibited a significant increase in mitotic aberrations over 1 bar treated as was the case with hypo/hypersaline treatments (p < 0.05). Conversely, an increase in hydrostatic pressure actually reduced the effects of spindle inhibition by the aneugen colchicine (p < 0.05). - The synergistic eco-barotoxicological relationship between chemical stress and elevations in hydrostatic pressure is largely a membrane integrity phenomenon.

  1. The role of hydrostatic pressure on developmental stages of Pomatoceros lamarcki (Polychaeta: Serpulidae) exposed to water accommodated fractions of crude oil and positive genotoxins at simulated depths of 1000-3000 m

    Energy Technology Data Exchange (ETDEWEB)

    Vevers, William F., E-mail: [Marine Biological Association, Laboratory, Citadel Hill, Plymouth PL1 2PB (United Kingdom); National Oceanography Centre, Empress Dock, Southampton SO14 3ZH (United Kingdom); School of Biological Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom); Dixon, David R. [Marine Biological Association, Laboratory, Citadel Hill, Plymouth PL1 2PB (United Kingdom); National Oceanography Centre, Empress Dock, Southampton SO14 3ZH (United Kingdom); Dixon, Linda R.J. [Marine Biological Association, Laboratory, Citadel Hill, Plymouth PL1 2PB (United Kingdom)


    The effect of high hydrostatic pressures on the ecotoxicological profile of pollutants is an unexplored research area. Using Pomatoceros lamarcki as a surrogate organism for this eco-barotoxicological study, it was found that in a 48 h larval bioassay with water accommodated fractions (WAF) of crude oil of up to 15.1 mg L{sup -1} (total hydrocarbon content) and hydrostatic pressures up to 300 bar (3000 m), an additive response was found (p < 0.001) rather than any synergism (p = 0.881). Comprehensive cytogenetic analysis of 6-h (15 deg. C) embryos exposed to WAF (0.19 mg L{sup -1}) at 100 bar showed no effects on mitotic fidelity or cell division rate over the 1 bar treatment. However, embryo's treated with the clastogen mitomycin-c at 100 bar exhibited a significant increase in mitotic aberrations over 1 bar treated as was the case with hypo/hypersaline treatments (p < 0.05). Conversely, an increase in hydrostatic pressure actually reduced the effects of spindle inhibition by the aneugen colchicine (p < 0.05). - The synergistic eco-barotoxicological relationship between chemical stress and elevations in hydrostatic pressure is largely a membrane integrity phenomenon.

  2. Secondary embryonic axis formation by transplantation of D quadrant micromeres in an oligochaete annelid. (United States)

    Nakamoto, Ayaki; Nagy, Lisa M; Shimizu, Takashi


    Among spiral cleaving embryos (e.g. mollusks and annelids), it has long been known that one blastomere at the four-cell stage, the D cell, and its direct descendants play an important role in axial pattern formation. Various studies have suggested that the D quadrant acts as the organizer of the embryonic axes in annelids, although this has never been demonstrated directly. Here we show that D quadrant micromeres (2d and 4d) of the oligochaete annelid Tubifex tubifex are essential for embryonic axis formation. When 2d and 4d were ablated the embryo developed into a rounded cell mass covered with an epithelial cell sheet. To examine whether 2d and 4d are sufficient for axis formation they were transplanted to an ectopic position in an otherwise intact embryo. The reconstituted embryo formed a secondary embryonic axis with a duplicated head and/or tail. Cell lineage analyses showed that neuroectoderm and mesoderm along the secondary axis were derived from the transplanted D quadrant micromeres and not from the host embryo. However, endodermal tissue along the secondary axis originated from the host embryo. Interestingly, when either 2d or 4d was transplanted separately to host embryos, the reconstituted embryos failed to form a secondary axis, suggesting that both 2d and 4d are required for secondary axis formation. Thus, the Tubifex D quadrant micromeres have the ability to organize axis formation, but they lack the ability to induce neuroectodermal tissues, a characteristic common to chordate primary embryonic organizers. PMID:21148182

  3. Gene structure and molecular phylogeny of the linker chains from the giant annelid hexagonal bilayer hemoglobins. (United States)

    Chabasse, Christine; Bailly, Xavier; Sanchez, Sophie; Rousselot, Morgane; Zal, Franck


    Giant extracellular hexagonal bilayer hemoglobin (HBL-Hb), found only in annelids, is an approximately 3500-kDa heteropolymeric structure involved in oxygen transport. The HBL-Hbs are comprised of globin and linker chains, the latter being required for the assembly of the quaternary structure. The linker chains, varying in size from 225 to 283 amino acids, have a conserved cysteine-rich domain within their N-terminal moiety that is homologous to the cysteine-rich modules constituting the ligand binding domain of the low-density lipoprotein receptor (LDLR) protein family found in many metazoans. We have investigated the gene structure of linkers from Arenicola marina, Alvinella pompejana, Nereis diversicolor, Lumbricus terrestris, and Riftia pachyptila. We found, contrary to the results obtained earlier with linker genes from N. diversicolor and L. terrestris, that in all of the foregoing cases, the linker LDL-A module is flanked by two phase 1 introns, as in the human LDLR gene, with two more introns in the 3' side whose positions varied with the species. In addition, we obtained 13 linker cDNAs that have been determined experimentally or found in the EST database LumbriBASE. A molecular phylogenetic analysis of the linker primary sequences demonstrated that they cluster into two distinct families of linker proteins. We propose that the common gene ancestor to annelid linker genes exhibited a four-intron and five-exon structure and gave rise to the two families subsequent to a duplication event. PMID:16838215

  4. Structural Characterization of Silica Particles Extracted from Grass Stenotaphrum secundatum: Biotransformation via Annelids

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    A. Espíndola-Gonzalez


    Full Text Available This study shows the structural characterization of silica particles extracted from Stenotaphrum secundatum (St. Augustine grass using an annelid-based biotransformation process. This bioprocess starts when St. Augustine grass is turned into humus by vermicompost, and then goes through calcination and acid treatment to obtain silica particles. To determine the effect of the bioprocess, silica particles without biotransformation were extracted directly from the sample of grass. The characterization of the silica particles was performed using Infrared (FTIR and Raman spectroscopy, Transmission Electron Microscopy (TEM, X-ray Diffraction (XRD, Dynamic Light Scattering (DLS, and Energy Dispersion Spectroscopy (EDS. Both types of particles showed differences in morphology and size. The particles without biotransformation were essentially amorphous while those obtained via annelids showed specific crystalline phases. The biological relationship between the metabolisms of worms and microorganisms and the organic-mineral matter causes changes to the particles' properties. The results of this study are important because they will allow synthesis of silica in cheaper and more ecofriendly ways.

  5. The loss of the hemoglobin H2S-binding function in annelids from sulfide-free habitats reveals molecular adaptation driven by Darwinian positive selection. (United States)

    Bailly, Xavier; Leroy, Riwanon; Carney, Susan; Collin, Olivier; Zal, Franck; Toulmond, Andre; Jollivet, Didier


    The hemoglobin of the deep-sea hydrothermal vent vestimentiferan Riftia pachyptila (annelid) is able to bind toxic hydrogen sulfide (H(2)S) to free cysteine residues and to transport it to fuel endosymbiotic sulfide-oxidising bacteria. The cysteine residues are conserved key amino acids in annelid globins living in sulfide-rich environments, but are absent in annelid globins from sulfide-free environments. Synonymous and nonsynonymous substitution analysis from two different sets of orthologous annelid globin genes from sulfide rich and sulfide free environments have been performed to understand how the sulfide-binding function of hemoglobin appeared and has been maintained during the course of evolution. This study reveals that the sites occupied by free-cysteine residues in annelids living in sulfide-rich environments and occupied by other amino acids in annelids from sulfide-free environments, have undergone positive selection in annelids from sulfide-free environments. We assumed that the high reactivity of cysteine residues became a disadvantage when H(2)S disappeared because free cysteines without their natural ligand had the capacity to interact with other blood components, disturb homeostasis, reduce fitness and thus could have been counterselected. To our knowledge, we pointed out for the first time a case of function loss driven by molecular adaptation rather than genetic drift. If constraint relaxation (H(2)S disappearance) led to the loss of the sulfide-binding function in modern annelids from sulfide-free environments, our work suggests that adaptation to sulfide-rich environments is a plesiomorphic feature, and thus that the annelid ancestor could have emerged in a sulfide-rich environment. PMID:12721359

  6. Novel mobbing strategies of a fish population against a sessile annelid predator. (United States)

    Lachat, Jose; Haag-Wackernagel, Daniel


    When searching for food, foraging fishes expose themselves to hidden predators. The strategies that maximize the survival of foraging fishes are not well understood. Here, we describe a novel type of mobbing behaviour displayed by foraging Scolopsis affinis. The fish direct sharp water jets towards the hidden sessile annelid predator Eunice aphroditois (Bobbit worm). We recognized two different behavioural roles for mobbers (i.e., initiator and subsequent participants). The first individual to exhibit behaviour indicating the discovery of the Bobbit directed, absolutely and per time unit, more water jets than the subsequent individuals that joined the mobbing. We found evidence that the mobbing impacted the behaviour of the Bobbit, e.g., by inducing retraction. S. affinis individuals either mob alone or form mobbing groups. We speculate that this behaviour may provide social benefits for its conspecifics by securing foraging territories for S. affinis. Our results reveal a sophisticated and complex behavioural strategy to protect against a hidden predator. PMID:27615670

  7. The impact of paralogy on phylogenomic studies - a case study on annelid relationships.

    Directory of Open Access Journals (Sweden)

    Torsten H Struck

    Full Text Available Phylogenomic studies based on hundreds of genes derived from expressed sequence tags libraries are increasingly used to reveal the phylogeny of taxa. A prerequisite for these studies is the assignment of genes into clusters of orthologous sequences. Sophisticated methods of orthology prediction are used in such analyses, but it is rarely assessed whether paralogous sequences have been erroneously grouped together as orthologous sequences after the prediction, and whether this had an impact on the phylogenetic reconstruction using a super-matrix approach. Herein, I tested the impact of paralogous sequences on the reconstruction of annelid relationships based on phylogenomic datasets. Using single-partition analyses, screening for bootstrap support, blast searches and pruning of sequences in the supermatrix, wrongly assigned paralogous sequences were found in eight partitions and the placement of five taxa (the annelids Owenia, Scoloplos, Sthenelais and Eurythoe and the nemertean Cerebratulus including the robust bootstrap support could be attributed to the presence of paralogous sequences in two partitions. Excluding these sequences resulted in a different, weaker supported placement for these taxa. Moreover, the analyses revealed that paralogous sequences impacted the reconstruction when only a single taxon represented a previously supported higher taxon such as a polychaete family. One possibility of a priori detection of wrongly assigned paralogous sequences could combine 1 a screening of single-partition analyses based on criteria such as nodal support or internal branch length with 2 blast searches of suspicious cases as presented herein. Also possible are a posteriori approaches in which support for specific clades is investigated by comparing alternative hypotheses based on differences in per-site likelihoods. Increasing the sizes of EST libraries will also decrease the likelihood of wrongly assigned paralogous sequences, and in the case

  8. Expression pattern of annelid Zic in embryonic development of the oligochaete Tubifex tubifex. (United States)

    Takahashi, Hirokazu; Shimizu, Takashi; Aruga, Jun


    Embryonic expression of a Zic homologue (Ttu-Zic) was examined in the oligochaete annelid Tubifex tubifex. The body plan of T. tubifex is characterized by obvious segmentation in the ectoderm and mesoderm. Ttu-Zic expression is detected in the mesodermal germ band and a subset of micromere descendants. Ttu-Zic is transiently expressed in primary m-blast cells (i.e., founder cells of mesodermal segments) as early as the time of their birth from M teloblasts. During its development, each mesodermal segment experiences two additional phases of Ttu-Zic expression. Ttu-Zic expression in micromere descendants is seen on the anterior surfaces of embryos undergoing teloblastogenesis; subsequently, these cells proliferate to form bilateral clusters, which then become internalized. Finally, clusters of Ttu-Zic-expressing cells are found in the center of the prostomium, corresponding to the cerebral ganglion. The Ttu-Zic expression profile in the early embryogenesis of T. tubifex may be homologous to those of evolutionarily distant animals. PMID:18810489

  9. The ontogeny of nanos homologue expression in the oligochaete annelid Tubifex tubifex. (United States)

    Mohri, Ki-Ichi; Nakamoto, Ayaki; Shimizu, Takashi


    We have cloned and characterized the expression of a nanos homologue (designated Ttu-nos) from the oligochaete annelid Tubifex tubifex. Ttu-nos mRNA is distributed broadly throughout the early cleavage stages. Ttu-nos is expressed in most if not all of the early blastomeres, in which Ttu-nos RNA associates with pole plasms. Ttu-nos transcripts are concentrated to 2d and 4d cells. Shortly after 2d(111) (derived from 2d cell) divides into a bilateral pair of NOPQ proteloblasts, Ttu-nos RNA vanishes from the embryo, which is soon followed by the resumption of Ttu-nos expression in nascent primary blast cells produced by teloblasts. The resumption of Ttu-nos expression occurs only in a subset of teloblast lineages (viz., M, N and Q). After Ttu-nos expression is retained in the germ band for a while, it disappears in anterior-to-posterior progression. At the end of embryogenesis, there is no trace of Ttu-nos expression. Thereafter, growing juveniles do not show any sign of Ttu-nos expression, either. The first sign of Ttu-nos expression is detected in oocytes in the ovary of young adults (ca 40 days after hatching), and its expression continues in growing oocytes that undergo yolk deposition and maturation in the ovisac. PMID:26577746

  10. Life history and seasonal breeding of the deep-sea annelid Ophryotrocha sp. (Polychaeta: Dorvelleidae) (United States)

    Mercier, Annie; Baillon, Sandrine; Hamel, Jean-François


    Shallow-water annelids of the genus Ophryotrocha have become a popular biological system for exploring ecological, behavioral, developmental, and toxicological questions. Here we report on the successful maintenance in holding tanks, complete life cycle, and reproductive phenology of a first deep-water representative that could be used as a model species. This Ophryotrocha, which has yet to be formally described, is large (12-16 mm long) and exhibits simultaneous hermaphroditism. Specimens collected off northeast Newfoundland (eastern Canada) between 500 and 1500 m depth were monitored under flow-through laboratory conditions for over three years. They consistently exhibited seasonal feeding from April to February, followed by a reproductive season between February and May. Gametogenesis was initiated in early January and completed in early to mid-February, followed by courtship, which mainly involved pairs of individuals attached head to tail for hours to days. Transparent gelatinous masses containing 80-110 eggs were laid from mid-February to late-March. Propagules developed in the mass to the 1-chaetiger stage and, at an ambient temperature of ~1-4 °C, offspring emerged 30-45 days post-laying. Only ~40-45% of the eggs laid developed to the 1-chaetiger stage, with evidence of adelphophagy. After emerging from the gelatinous mass, 1-chaetiger stages remained aggregated and were guarded by adults for a few days before dispersing. All parents died following the dispersal of their offspring. The new generation reached sexual maturity in 8-9 months and was ready to reproduce the following January-February. A few cases of segmenting adult worms were also observed. Three complete generations developed successively to sexual maturity over the course of this study.

  11. Mesonerilla neridae, n. sp. (Nerillidae): First meiofaunal annelid from deep-sea hydrothermal vents

    DEFF Research Database (Denmark)

    Worsaae, Katrine; Rouse, Greg W


    deep-sea hydrothermal vent associated nerillid, this is the first record of an adult meiofaunal annelid from deep-sea hydrothermal vent areas and the first record of Mesonerilla from the deep sea. Based on the new material we here describe a new species of Mesonerilla, M. neridae sp. nov., with nine......) in 2005, six specimens of a new species of Mesonerilla were collected at depths of 2234-2649 m. Samples were taken via DSV Alvin with a slurp gun collecting fine silt and volcanic glass shards in cracks, fissures, and mussel beds from 5-20 m away from active venting areas. As well as being the first...

  12. What role do annelid neoblasts play? A comparison of the regeneration patterns in a neoblast-bearing and a neoblast-lacking enchytraeid oligochaete.

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    Maroko Myohara

    Full Text Available The term 'neoblast' was originally coined for a particular type of cell that had been observed during annelid regeneration, but is now used to describe the pluripotent/totipotent stem cells that are indispensable for planarian regeneration. Despite having the same name, however, planarian and annelid neoblasts are morphologically and functionally distinct, and many annelid species that lack neoblasts can nonetheless substantially regenerate. To further elucidate the functions of the annelid neoblasts, a comparison was made between the regeneration patterns of two enchytraeid oligochaetes, Enchytraeus japonensis and Enchytraeus buchholzi, which possess and lack neoblasts, respectively. In E. japonensis, which can reproduce asexually by fragmentation and subsequent regeneration, neoblasts are present in all segments except for the eight anterior-most segments including the seven head-specific segments, and all body fragments containing neoblasts can regenerate a complete head and a complete tail, irrespective of the region of the body from which they were originally derived. In E. japonensis, therefore, no antero-posterior gradient of regeneration ability exists in the trunk region. However, when amputation was carried out within the head region, where neoblasts are absent, the number of regenerated segments was found to be dependent on the level of amputation along the body axis. In E. buchholzi, which reproduces only sexually and lacks neoblasts in all segments, complete heads were never regenerated and incomplete (hypomeric heads could be regenerated only from the anterior region of the body. Such an antero-posterior gradient of regeneration ability was observed for both the anterior and posterior regeneration in the whole body of E. buchholzi. These results indicate that the presence of neoblasts correlates with the absence of an antero-posterior gradient of regeneration ability along the body axis, and suggest that the annelid neoblasts are

  13. Transcriptome profiling of developmental and xenobiotic responses in a keystone soil animal, the oligochaete annelid Lumbricus rubellus

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    Morgan A John


    Full Text Available Abstract Background Natural contamination and anthropogenic pollution of soils are likely to be major determinants of functioning and survival of keystone invertebrate taxa. Soil animals will have both evolutionary adaptation and genetically programmed responses to these toxic chemicals, but mechanistic understanding of such is sparse. The clitellate annelid Lumbricus rubellus is a model organism for soil health testing, but genetic data have been lacking. Results We generated a 17,000 sequence expressed sequence tag dataset, defining ~8,100 different putative genes, and built an 8,000-element transcriptome microarray for L. rubellus. Strikingly, less than half the putative genes (43% were assigned annotations from the gene ontology (GO system; this reflects the phylogenetic uniqueness of earthworms compared to the well-annotated model animals. The microarray was used to identify adult- and juvenile-specific transcript profiles in untreated animals and to determine dose-response transcription profiles following exposure to three xenobiotics from different chemical classes: inorganic (the metal cadmium, organic (the polycyclic aromatic hydrocarbon fluoranthene, and agrochemical (the herbicide atrazine. Analysis of these profiles revealed compound-specific fingerprints which identify the molecular responses of this annelid to each contaminant. The data and analyses are available in an integrated database, LumbriBASE. Conclusion L. rubellus has a complex response to contaminant exposure, but this can be efficiently analysed using molecular methods, revealing unique response profiles for different classes of effector. These profiles may assist in the development of novel monitoring or bioremediation protocols, as well as in understanding the ecosystem effects of exposure.

  14. Transcriptome characterization via 454 pyrosequencing of the annelid Pristina leidyi, an emerging model for studying the evolution of regeneration

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    Nyberg Kevin G


    Full Text Available Abstract Background The naid annelids contain a number of species that vary in their ability to regenerate lost body parts, making them excellent candidates for evolution of regeneration studies. However, scant sequence data exists to facilitate such studies. We constructed a cDNA library from the naid Pristina leidyi, a species that is highly regenerative and also reproduces asexually by fission, using material from a range of regeneration and fission stages for our library. We then sequenced the transcriptome of P. leidyi using 454 technology. Results 454 sequencing produced 1,550,174 reads with an average read length of 376 nucleotides. Assembly of 454 sequence reads resulted in 64,522 isogroups and 46,679 singletons for a total of 111,201 unigenes in this transcriptome. We estimate that over 95% of the transcripts in our library are present in our transcriptome. 17.7% of isogroups had significant BLAST hits to the UniProt database and these include putative homologs of a number of genes relevant to regeneration research. Although many sequences are incomplete, the mean sequence length of transcripts (isotigs is 707 nucleotides. Thus, many sequences are large enough to be immediately useful for downstream applications such as gene expression analyses. Using in situ hybridization, we show that two Wnt/β-catenin pathway genes (homologs of frizzled and β-catenin present in our transcriptome are expressed in the regeneration blastema of P. leidyi, demonstrating the usefulness of this resource for regeneration research. Conclusions 454 sequencing is a rapid and efficient approach for identifying large numbers of genes in an organism that lacks a sequenced genome. This transcriptome dataset will be a valuable resource for molecular analyses of regeneration in P. leidyi and will serve as a starting point for comparisons to non-regenerating naids. It also contributes significantly to the still limited genomic resources available for annelids and

  15. Identification and Functional Characterization of a Novel Acetylcholine-binding Protein from the Marine Annelid Capitella teleta

    Energy Technology Data Exchange (ETDEWEB)

    McCormack, T.; Petrovich,; Mercier, K; DeRose, E; Cuneo, M; Williams, J; Johnson, K; Lamb, P; London, R; Yakel, J


    We identified a homologue of the molluscan acetylcholine-binding protein (AChBP) in the marine polychaete Capitella teleta, from the annelid phylum. The amino acid sequence of C. teleta AChBP (ct-AChBP) is 21-30% identical with those of known molluscan AChBPs. Sequence alignments indicate that ct-AChBP has a shortened Cys loop compared to other Cys loop receptors, and a variation on a conserved Cys loop triad, which is associated with ligand binding in other AChBPs and nicotinic ACh receptor (nAChR) {alpha} subunits. Within the D loop of ct-AChBP, a conserved aromatic residue (Tyr or Trp) in nAChRs and molluscan AChBPs, which has been implicated directly in ligand binding, is substituted with an isoleucine. Mass spectrometry results indicate that Asn122 and Asn216 of ct-AChBP are glycosylated when expressed using HEK293 cells. Small-angle X-ray scattering data suggest that the overall shape of ct-AChBP in the apo or unliganded state is similar to that of homologues with known pentameric crystal structures. NMR experiments show that acetylcholine, nicotine, and {alpha}-bungarotoxin bind to ct-AChBP with high affinity, with KD values of 28.7 {micro}M, 209 nM, and 110 nM, respectively. Choline bound with a lower affinity (K{sub D} = 163 {micro}M). Our finding of a functional AChBP in a marine annelid demonstrates that AChBPs may exhibit variations in hallmark motifs such as ligand-binding residues and Cys loop length and shows conclusively that this neurotransmitter binding protein is not limited to the phylum Mollusca.

  16. Developmental significance of D quadrant micromeres 2d and 4d in the oligochaete annelid Tubifex tubifex. (United States)

    Shimizu, Takashi; Nakamoto, Ayaki


    The annelidTubifex tubifex is a cosmopolitan freshwater oligochaete and a member of the Spiralia, a large group of invertebrate phyla displaying spiral development. Because its developing eggs are easily obtained in the laboratory, this animal has long been used as material for developmental studies, especially spiralian embryology. In spiralian embryos, it has long been known that one blastomere at the four-cell stage, the D cell, and its direct descendants play an important role in axial pattern formation. Various studies have suggested that the D quadrant functions as the organizer of the embryonic axes in molluscs and annelids, and it has recently been demonstrated that the D quadrant micromeres, 2d(11) and 4d, which had been transplanted to an ectopic position in an otherwise intact embryo induce a secondary embryonic axis to give rise to the formation of duplicated heads and/or tails. That 2d and 4d play a pivotal role in Tubifex embryonic development was first suggested from the classic cell-ablation experiments carried out in the early 1920s, and this has been confirmed by the recent cell-ablation/restoration experiments using cell-labeling with lineage tracers. These studies have also shown that in the operated embryos, none of the remaining cells can replace the missing 2d and 4d and that both 2d and 4d are determined as ectodermal and mesodermal precursors, respectively, at the time of their birth. The anteroposterior polarity of these micromeres is also specified at the time of their birth, suggesting that nascent 2d and 4d are specified in their axial properties as well as in cell fate decision. PMID:25690961

  17. Hedistin: A novel antimicrobial peptide containing bromotryptophan constitutively expressed in the NK cells-like of the marine annelid, Nereis diversicolor. (United States)

    Tasiemski, Aurélie; Schikorski, David; Le Marrec-Croq, Françoise; Pontoire-Van Camp, Christelle; Boidin-Wichlacz, Céline; Sautière, Pierre-Eric


    A novel antimicrobial peptide, named hedistin was identified from the coelomocytes of Nereis diversicolor. Hedistin shows no obvious similarities with other known peptides and constitutes the first antimicrobial peptide containing bromotryptophans demonstrated in annelids. cDNA and mass spectrometry analysis revealed that, upon bacteria challenge, this peptide is secreted following processing of a precursor containing a signal peptide and prosequences. Hedistin was shown to possess an activity against a large spectrum of bacteria including the methicillin resistant Staphylococcus aureus and Vibrio alginolyticus. The gene was demonstrated to be constitutively and exclusively expressed in circulating NK cells like known to play an important role in the immunity of the sand worm. These data contrast with those observed in another annelid, the leech, in which genes coding for antimicrobial peptides are upregulated in a specific tissue and peptides are rapidly released into the hemolymph after septic injury. PMID:17210178

  18. Polypeptide chain composition diversity of hexagonal-bilayer haemoglobins within a single family of annelids, the alvinellidae. (United States)

    Zal, F; Green, B N; Martineu, P; Lallier, F H; Toulmond, A; Vinogradov, S N; Childress, J J


    Following previous analysis of the structure of Alvinella pompejana heaxagonal-bilayer haemoglobin (HBL Hb) [1], we report in this paper the structure of three other HBL Hbs belonging to Alvinella caudata, Paralvinella grasslei and Paralvinella palmiformis, members of the Alvinellidae, annelid family strictly endemic to deep-sea hydrothermal vents located on the ridge crests in the Pacific ocean. The multi-angle laser light scattering (MALLS) and fast protein liquid chromatography (FPLC) analysis revealed a broad range of molecular masses for the extracellular Hb molecules, 3517 +/- 14 kDa (A. caudata), 3822 +/- 28 kDa (P. grasslei) and 3750 +/- 150 kDa (P. palmiformis). Native and derivative Hbs (reduced, carbamidomethylated and deglycosylated) were analysed by electrospray ionization mass spectroscopy (ESI-MS) and the data was processed by the maximum entropy deconvolution system (MaxEnt). The most important difference between alvinellid HBL Hbs was the variation in their composition, from two to four monomeric globin chains, and from one to four linker chains. Therefore, despite the fact that all these species belong to a single family, notable differences in the polypeptide chain composition of their HBL Hbs were observed, probably accounting for their different functional properties as previously reported by this group Toulmond, A., El Idrissi Slitine, F., De Frescheville, J. & Jouin, C. (1990) Biol. Bull. 179, 366-373. PMID:10931208

  19. Embryonic expression of p68, a DEAD-box RNA helicase, in the oligochaete annelid Tubifex tubifex. (United States)

    Oyama, Atsuko; Yoshida, Hiroshi; Shimizu, Takashi


    We have cloned and characterized the expression of a p68 homologue (designated Ttu-p68) from the oligochaete annelid Tubifex tubifex. Ttu-p68 mRNA is distributed broadly throughout the early stages. Ttu-p68 is expressed in all of the early blastomeres, in which Ttu-p68 RNA associates with pole plasms. Ttu-p68 transcripts are concentrated to 4d cell but not to 2d cell. During gastrulation, expression of Ttu-p68 is restricted to elongating germ bands (GBs) and an anteriormost crescent of micromere descendants on both sides of the embryo. During body elongation that follows gastrulation, expression of Ttu-p68 is further restricted to the stomodaeum (derived from the micromere crescent), ventral ganglia, lateral dots (corresponding to dorsal and ventral setal sacs), ventral large cells (that resemble presumptive primordial germ cells) in segments VIII-XII, and a bilateral pair of cell clusters at the caudal end. At the end of embryogenesis, Ttu-p68 expression persists exclusively in the tail and the lining epithelium of the pharynx. PMID:18381252

  20. Expression and evolution studies of ets genes in a primitive coelomate, the polychaete annelid, Hediste (Nereis) diversicolor. (United States)

    Bocquet-Muchembled, Béatrice; Leroux, Régine; Chotteau-Lelièvre, Anne; Vergoten, Gérard; Fontaine, François


    The Ets family includes numerous proteins with a highly conserved DNA-binding domain of 85 amino acids named the ETS domain. Phylogenetic analyses from ETS domains revealed that this family could be divided into 13 groups, among them are ETS and ERG. The ets genes are present in the Metazoan kingdom and we have previously characterized the Nd ets and Nd erg genes in the polychaete annelid Hediste diversicolor. Here, we isolated a fragment encoding the ETS domain from Nd Ets, by genomic library screening. By Northern blot analysis, we showed that this gene was transcribed as one major mRNA of 2.6 kb and one minor mRNA of 3.2 kb. By in situ hybridization, we observed that Nd ets was expressed in the intestine and oocytes and that Nd erg was expressed in cellular clumps present in the coelomic cavity, in an area of proliferating cells situated between the last metamere and the pygidium. Finally, we showed that Nd erg shared the expression pattern of Nd ets in oocytes. Molecular modeling studies have revealed that the spatial structure of ETS domain of Nd Ets and Nd Erg was conserved, in comparison to the murine Ets-1 and human Fli-1 proteins, respectively. PMID:12128055

  1. Primordial germ cells in an oligochaete annelid are specified according to the birth rank order in the mesodermal teloblast lineage. (United States)

    Kato, Yukie; Nakamoto, Ayaki; Shiomi, Inori; Nakao, Hajime; Shimizu, Takashi


    The primordial germ cells (PGCs) in the oligochaete annelid Tubifex tubifex are descentants of the mesodermal (M) teloblast and are located in the two midbody segments X and XI in which they serve as germline precursors forming the testicular gonad and the ovarian gonad, respectively. During embryogenesis, vasa-expressing cells (termed presumptive PGCs or pre-PGCs) emerge in a variable set of midbody segments including the genital segments (X and XI); at the end of embryogenesis, pre-PGCs are confined to the genital segments, where they become PGCs in the juvenile. Here, using live imaging of pre-PGCs, we have demonstrated that during Tubifex embryogenesis, pre-PGCs (defined by Vasa expression) stay in segments where they have emerged, suggesting that it is unlikely that pre-PGCs move intersegmentally during embryogenesis. Thus, it is apparent that pre-PGCs derived from the 10th and 11th M teloblast-derived primary m blast cells (designated m10 and m11) that give rise, respectively, to segments X and XI are specified in situ as PGCs and that those born in other segments become undetectable at the end of embryogenesis. To address the mechanisms for this segment-specific development of PGCs, we have performed a set of cell-transplantation experiments as well as cell-ablation experiments. When m10 and m11 that are normally located in the mid region of the embryo were placed in positions near the anterior end of the host embryo, these cells formed two consecutive segments, which exhibited Vasa-positive PGC-like cells at early juvenile stage. This suggests that in terms of PGC generation, the fates of m10 and m11 remain unchanged even if they are placed in ectopic positions along the anteroposterior axis. Nor was the fate of m10 and m11 changed even if mesodermal blast cell chains preceding or succeeding m10 and m11 were absent. In a previous study, it was shown that PGC development in segments X and XI occurs normally in the absence of the overlying ectoderm. All this

  2. atonal- and achaete-scute-related genes in the annelid Platynereis dumerilii: insights into the evolution of neural basic-Helix-Loop-Helix genes

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    Arendt Detlev


    Full Text Available Abstract Background Functional studies in model organisms, such as vertebrates and Drosophila, have shown that basic Helix-loop-Helix (bHLH proteins have important roles in different steps of neurogenesis, from the acquisition of neural fate to the differentiation into specific neural cell types. However, these studies highlighted many differences in the expression and function of orthologous bHLH proteins during neural development between vertebrates and Drosophila. To understand how the functions of neural bHLH genes have evolved among bilaterians, we have performed a detailed study of bHLH genes during nervous system development in the polychaete annelid, Platynereis dumerilii, an organism which is evolutionary distant from both Drosophila and vertebrates. Results We have studied Platynereis orthologs of the most important vertebrate neural bHLH genes, i.e. achaete-scute, neurogenin, atonal, olig, and NeuroD genes, the latter two being genes absent of the Drosophila genome. We observed that all these genes have specific expression patterns during nervous system formation in Platynereis. Our data suggest that in Platynereis, like in vertebrates but unlike Drosophila, (i neurogenin is the main proneural gene for the formation of the trunk central nervous system, (ii achaete-scute and olig genes are involved in neural subtype specification in the central nervous system, in particular in the specification of the serotonergic phenotype. In addition, we found that the Platynereis NeuroD gene has a broad and early neuroectodermal expression, which is completely different from the neuronal expression of vertebrate NeuroD genes. Conclusion Our analysis suggests that the Platynereis bHLH genes have both proneural and neuronal specification functions, in a way more akin to the vertebrate situation than to that of Drosophila. We conclude that these features are ancestral to bilaterians and have been conserved in the vertebrates and annelids lineages, but

  3. Deep transcriptome-sequencing and proteome analysis of the hydrothermal vent annelid Alvinella pompejana identifies the CvP-bias as a robust measure of eukaryotic thermostability

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    Holder Thomas


    Full Text Available Abstract Background Alvinella pompejana is an annelid worm that inhabits deep-sea hydrothermal vent sites in the Pacific Ocean. Living at a depth of approximately 2500 meters, these worms experience extreme environmental conditions, including high temperature and pressure as well as high levels of sulfide and heavy metals. A. pompejana is one of the most thermotolerant metazoans, making this animal a subject of great interest for studies of eukaryotic thermoadaptation. Results In order to complement existing EST resources we performed deep sequencing of the A. pompejana transcriptome. We identified several thousand novel protein-coding transcripts, nearly doubling the sequence data for this annelid. We then performed an extensive survey of previously established prokaryotic thermoadaptation measures to search for global signals of thermoadaptation in A. pompejana in comparison with mesophilic eukaryotes. In an orthologous set of 457 proteins, we found that the best indicator of thermoadaptation was the difference in frequency of charged versus polar residues (CvP-bias, which was highest in A. pompejana. CvP-bias robustly distinguished prokaryotic thermophiles from prokaryotic mesophiles, as well as the thermophilic fungus Chaetomium thermophilum from mesophilic eukaryotes. Experimental values for thermophilic proteins supported higher CvP-bias as a measure of thermal stability when compared to their mesophilic orthologs. Proteome-wide mean CvP-bias also correlated with the body temperatures of homeothermic birds and mammals. Conclusions Our work extends the transcriptome resources for A. pompejana and identifies the CvP-bias as a robust and widely applicable measure of eukaryotic thermoadaptation. Reviewer This article was reviewed by Sándor Pongor, L. Aravind and Anthony M. Poole.

  4. Expression of the pair-rule gene homologs runt, Pax3/7, even-skipped-1 and even-skipped-2 during larval and juvenile development of the polychaete annelid Capitella teleta does not support a role in segmentation

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    Seaver Elaine C


    Full Text Available Abstract Background Annelids and arthropods each possess a segmented body. Whether this similarity represents an evolutionary convergence or inheritance from a common segmented ancestor is the subject of ongoing investigation. Methods To investigate whether annelids and arthropods share molecular components that control segmentation, we isolated orthologs of the Drosophila melanogaster pair-rule genes, runt, paired (Pax3/7 and eve, from the polychaete annelid Capitella teleta and used whole mount in situ hybridization to characterize their expression patterns. Results When segments first appear, expression of the single C. teleta runt ortholog is only detected in the brain. Later, Ct-runt is expressed in the ventral nerve cord, foregut and hindgut. Analysis of Pax genes in the C. teleta genome reveals the presence of a single Pax3/7 ortholog. Ct-Pax3/7 is initially detected in the mid-body prior to segmentation, but is restricted to two longitudinal bands in the ventral ectoderm. Each of the two C. teleta eve orthologs has a unique and complex expression pattern, although there is partial overlap in several tissues. Prior to and during segment formation, Ct-eve1 and Ct-eve2 are both expressed in the bilaterial pair of mesoteloblasts, while Ct-eve1 is expressed in the descendant mesodermal band cells. At later stages, Ct-eve2 is expressed in the central and peripheral nervous system, and in mesoderm along the dorsal midline. In late stage larvae and adults, Ct-eve1 and Ct-eve2 are expressed in the posterior growth zone. Conclusions C. teleta eve, Pax3/7 and runt homologs all have distinct expression patterns and share expression domains with homologs from other bilaterians. None of the pair-rule orthologs examined in C. teleta exhibit segmental or pair-rule stripes of expression in the ectoderm or mesoderm, consistent with an independent origin of segmentation between annelids and arthropods.

  5. An Assessment of the Delayed Effects of Exposure to CuO Nanoparticles and CuCl2 Spiked Sediment on Mortality and Burrowing Behaviour of the Freshwater Annelid Tubifex tubifex


    Holm, Anne; Absalon, Lucas; Jørgensen, Michael; Charalambous, Nayia


    Copper nanoparticles are being used more and more frequently in our everyday life; this leads to the question of what the effects on the environment and organisms living in the contaminated ecosystems are. This report seeks to help answering this question, by researching if the sedimentassociated copper (two forms, CuO NPs or Cu-ions) exposure has a delayed effects on the mortality and burrowing behaviour of the annelid Tubifex tubifex after an exposure period of four days. This is done by ex...

  6. The effects of polycyclic aromatic hydrocarbons and heavy metals on terrestrial annelids in urban soils O efeito de hidrocarbonetos aromáticos policíclicos e metais pesados em anelídeos terrestres de solos urbanos

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    Pižl Václav


    Full Text Available The effect of soil contamination by polycyclic aromatic hydrocarbons (PAH and heavy metals on earthworms and enchytraeids was studied in urban parks, in Brno, Czech Republic. In spring and autumn 2007, annelids were collected and soil samples taken in lawns along transects, at three different distances (1, 5 and 30 m from streets with heavy traffic. In both seasons, two parks with two transects each were sampled. Earthworms were collected using the electrical octet method. Enchytraeids were extracted by the wet funnel method from soil cores. All collected annelids were counted and identified. Basic chemical parameters and concentrations of 16 PAH, Cd, Cu, Pb, and Zn were analysed from soil from each sampling point. PAH concentrations were rather low, decreasing with the distance from the street in spring but not in autumn. Heavy metal concentrations did not decrease significantly with increasing distance. Annelid densities did not significantly differ between distances, although there was a trend of increase in the number of earthworms with increasing distance. There were no significant correlations between soil content of PAH or heavy metals and earthworm or enchytraeid densities. Earthworm density and biomass were negatively correlated with soil pH; and enchytraeid density was positively correlated with soil phosphorus.O efeito da contaminação do solo por hidrocarbonetos aromáticos policíclicos (PAH e metais pesados em minhocas e enquitreídeos foi estudado em parques urbanos, em Brno, República Tcheca. Na primavera e outono de 2007, os anelídeos foram coletados, e amostras de solo foram retiradas de gramados ao longo de transectos, em três diferentes distâncias (1, 5 e 30 m de ruas com muito tráfego. Nas duas estações, foram amostrados dois parques com dois transectos cada um. As minhocas com uso do método do octeto elétrico, e os enquitreídeos foram extraídos das amostras de solo pelo método do funil úmido. Todos os anel

  7. Mechanism of wound healing in annelids

    Directory of Open Access Journals (Sweden)

    M Grdisa


    Full Text Available All animals possess some type of tissue repair mechanism. In some species, the capacity to repair tissues is limited to the healing of wounds, but others posses a striking repair capability to replace the entire organs. It has been reported that some mechanisms, namely extracellular matrix remodeling, appear to occur in most repair processes. However, it remains unclear to what extent the process of wound healing is similar to organ regeneration.

  8. The making of a branching annelid


    Aguado, M. Teresa; Glasby, Christopher J.; Schroeder, Paul C.; Weigert, Anne; Bleidorn, Christoph


    Ramisyllis multicaudata is a member of Syllidae (Annelida, Errantia, Phyllodocida) with a remarkable branching body plan. Using a next-generation sequencing approach, the complete mitochondrial genomes of R. multicaudata and Trypanobia sp. are sequenced and analysed, representing the first ones from Syllidae. The gene order in these two syllids does not follow the order proposed as the putative ground pattern in Errantia. The phylogenetic relationships of R. multicaudata are discerned usin...

  9. Myoinhibitory peptide regulates feeding in the marine annelid Platynereis


    Williams, Elizabeth A.; Conzelmann, Markus; Jékely, Gáspár


    Background During larval settlement and metamorphosis, marine invertebrates undergo changes in habitat, morphology, behavior and physiology. This change between life-cycle stages is often associated with a change in diet or a transition between a non-feeding and a feeding form. How larvae regulate changes in feeding during this life-cycle transition is not well understood. Neuropeptides are known to regulate several aspects of feeding, such as food search, ingestion and digestion. The marine ...

  10. From mowing to grazing: Does the change in grassland management affect soil annelid assemblages?

    Czech Academy of Sciences Publication Activity Database

    Schlaghamerský, J.; Šídová, A.; Pižl, Václav


    Roč. 43, Suppl. 1 (2007), S72-S78. ISSN 1164-5563 R&D Projects: GA MŽP SE/620/11/03 Institutional research plan: CEZ:AV0Z60660521 Keywords : Lumbricidae * Enchytraeidae * Tubificidae Subject RIV: EH - Ecology, Behaviour Impact factor: 0.500, year: 2007

  11. And Lophotrochozoa Makes Three: Notch/Hes Signaling in Annelid Segmentation


    Rivera, Ajna S; Weisblat, David A.


    Segmentation is unquestionably a major factor in the evoluation of complex body plans, but how this trait itself evolved is unknown. Approaching this problem requires comparing the molecular mechanisms of segmentation in diverse segmented and unsegmented taxa. Notch/Hes signaling is involved in segmentation in sequentially segmenting vertebrates and arthropods, as judged by patterns of expression of one or more genes in this network and by the disruption of segmental patterning when Notch/Hes...

  12. Complete mitochondrial genome sequence of the polychaete annelidPlatynereis dumerilii

    Energy Technology Data Exchange (ETDEWEB)

    Boore, Jeffrey L.


    Complete mitochondrial genome sequences are now available for 126 metazoans (see Boore 1999; Mitochondrial Genomics link at, but the taxonomic representation is highly biased. For example, 80 are from a single phylum, Chordata, and show little variation for many molecular features. Arthropoda is represented by 16 taxa, Mollusca by eight, and Echinodermata by five, with only 17 others from the remaining {approx}30 metazoan phyla. With few exceptions (see Wolstenholme 1992 and Boore 1999) these are circular DNA molecules, about 16 kb in size, and encode the same set of 37 genes. A variety of non-standard names are sometimes used for animal mitochondrial genes; see Boore (1999) for gene nomenclature and a table of synonyms. Mitochondrial genome comparisons serve as a model of genome evolution. In this system, much smaller and simpler than that of the nucleus, are all of the same factors of genome evolution, where one may find tractable the changes in tRNA structure, base composition, genetic code, gene arrangement, etc. Further, patterns of mitochondrial gene rearrangements are an exceptionally reliable indicator of phylogenetic relationships (Smith et al.1993; Boore et al. 1995; Boore, Lavrov, and Brown 1998; Boore and Brown 1998, 2000; Dowton 1999; Stechmann and Schlegel 1999; Kurabayashi and Ueshima 2000). To these ends, we are sampling further the variation among major animal groups in features of their mitochondrial genomes.

  13. Bioconcentration de metaux lourds chez une annelide polychete estuarienne: Nereis diversicolor


    Septier, F.; Demuynck, S; Thomas, P; Dhainaut-courtois, N


    The concentrations of twelve heavy metals in sediments and in female Nereis diversicolor collected in the estuary of the River Aa and in the little harbour of Boulogne were investigated. Concentration variations which were sometimes considerable were found according to the site, the period of the year, the age of the animals and the cations studied. In addition, numerous intermetal correlations were detected in the nereis. Cytochemical and radioautographic studies revealed that the tegument a...

  14. Vasa, PL10, and Piwi gene expression during caudal regeneration of the polychaete annelid Alitta virens. (United States)

    Kozin, Vitaly V; Kostyuchenko, Roman P


    Polychaetes are famous for their outstanding ability to regenerate lost body parts. Moreover, these worms possess a number of ancestral features in anatomy, development, and genetics, making them particularly suitable for comparative studies. Thus, fundamental as well as new undisclosed so far features of regenerative processes may be revealed, using polychaetes as a model. In the present work, we aimed to analyze the molecular basis of caudal regeneration in the nereid polychaete Alitta virens (formerly Nereis virens). We focused on homologues genes of RNA helicases Vasa and PL10 and ncRNA-binding proteins Piwi. These markers are suggested to play a significant role in maintenance of undifferentiated state of primordial germ cells and multipotent stem cells across invertebrates. In normal conditions, A. virens homologues of Vasa, PL10, and Piwi were differentially expressed in the subterminal growth zone and germline cells. Caudal amputation induced expression of studied genes de novo, which further accompanies all steps of regeneration. An early appearance of the transcripts in wound epithelium and internal blastemal cells suggests involvement of these genes in the well-known cell dedifferentiation events that assure polychaete regeneration. Provided interpretation of the gene expression dynamics implies the primary restoration of the pygidium and growth zone, which promotes following segment formation. Obtained results are valuable as a molecular fingerprint of the alterations occurring in regulatory state of locally regenerating tissues. PMID:25772273

  15. Stimulation by cadmium of myohemerythrin-like cells in the gut of the annelid Nereis diversicolor. (United States)

    Demuynck, Sylvain; Bocquet-Muchembled, Beatrice; Deloffre, Laurence; Grumiaux, Fabien; Leprêtre, Alain


    Isolated guts of Nereis diversicolor revealed the existence of a cadmium-binding protein, the MPII, belonging to the group of hemerythrins and myohemerythrins. The presence of MPII in the cells of the intestine was demonstrated by immunocytochemistry, using anti-MPII, a monoclonal antibody. In addition, using in situ hybridization and northern blotting, it was shown that MPII-cells are the site of synthesis of this molecule. Exposure of the worms to cadmium led to the cellular activation process of MPII-cells (i.e. transformation of the nucleolus, development of the endoplasmic reticulum and the Golgi apparatus), although MPII mRNA transcript levels were unchanged. Enzyme-linked immunosorbent assay (ELISA) of gut extracts revealed that MPII levels were increased after exposure to Cd, so it appears that this protein is synthesized as a response to Cd exposure without any new synthesis of mRNA. This mechanism of regulation is quite similar to that reported in the case of mammalian ferritin and may be involved in the regulation of Cd levels in this worm. PMID:14978053

  16. Experimental study of the retention of zinc 65 by sediment and polychaete annelids (Nereis diversicolor Muller)

    Energy Technology Data Exchange (ETDEWEB)

    Baudin, J.P. (CEA Centre d' Etudes Nucleaires de Cadarache, 13 - Saint-Paul-les-Durance (France). Dept. de Protection)


    Zinc 65 is a radionuclide with an intermediate half-life (245 days). It is an isotope of a biological trace element which can be found in some liquid wastes released by nuclear facilities. The first part of the paper concerns zinc 65 transfer from water to sediment. This process is essentially characterised by its rapidity and intensity. After 48 hours water loses 50% of its activity and transfer reaches 100% beyond the 20th day. Zinc 65 is strongly bound to the sediment and its desorption is almost non-existent. The second part reports the results about zinc 65 contamination of Nereis diversicolor, a species which can be considered as a vehicle of recirculation for the radionuclide fixed in the sediment. This assumption is partly verified although zinc 65 accumulation by Nereis diversicolor from water is 20 times more important than from sediment.

  17. Transplants in annelids, nemerteans and planarians: a tool for embryology, immunology, endocrinology and regeneration research

    Directory of Open Access Journals (Sweden)

    EE Zattara


    Full Text Available While transplantation procedures are often associated with biomedical applications, they are also an invaluable tool for basic research. This review focuses on how transplantation techniques have been used to understand the biology of three large lophotrochozoan phyla: Annelida, Nemertea and Platyhelmintha. I describe how transplantation paradigms have uncovered fundamental principles regarding the embryology, immunology, endocrinology and regeneration biology of representative species within these three groups. In particular, embryologists have used blastomere transplantations to show that both mosaic and regulative development occurs in animals within the phyla. Immunologists have used transplantation techniques to demonstrate that these invertebrates mount a variety of innate immune responses, some of which include surprising features that classically characterize adaptive immunity. Endocrinologists have used transplantation experiments to uncover hormonal requirements for sexual development and maturation. Meanwhile, regeneration biologists continue to address fundamental questions regarding tissue polarity, post-embryonic patterning, stem cell physiology, and the role of the nervous system in regeneration. Along with recent technical and conceptual advances, transplantation remains a powerful tool for invertebrate research.

  18. The Lophotrochozoan TGF-β signalling cassette - diversification and conservation in a key signalling pathway. (United States)

    Kenny, Nathan J; Namigai, Erica K O; Dearden, Peter K; Hui, Jerome H L; Grande, Cristina; Shimeld, Sebastian M


    TGF-β signalling plays a key role in the patterning of metazoan body plans and growth. It is widely regarded as a 'module' capable of co-option into novel functions. The TGF-β pathway arose in the Metazoan lineage, and while it is generally regarded as well conserved across evolutionary time, its components have been largely studied in the Ecdysozoa and Deuterostomia. The recent discovery of the Nodal molecule in molluscs has underlined the necessity of untangling this signalling network in lophotrochozoans in order to truly comprehend the evolution, conservation and diversification of this key pathway. Three novel genome resources, the mollusc Patella vulgata, annelid Pomatoceros lamarcki and rotifer Brachionus plicatilis, along with other publicly available data, were searched for the presence of TGF-β pathway genes. Bayesian and Maximum Likelihood analyses, along with some consideration of conserved domain structure, was used to confirm gene identity. Analysis revealed conservation of key components within the canonical pathway, allied with extensive diversification of TGF-β ligands and partial loss of genes encoding pathway inhibitors in some lophotrochozoan lineages. We fully describe the TGF-β signalling cassette of a range of lophotrochozoans, allowing firm inference to be drawn as to the ancestral state of this pathway in this Superphylum. The TGF-β signalling cascade's reputation as being highly conserved across the Metazoa is reinforced. Diversification within the activin-like complement, as well as potential wide loss of regulatory steps in some Phyla, hint at specific evolutionary implications for aspects of this cascade's functionality in this Superphylum. PMID:25690968

  19. Proteomic Changes between Male and Female Worms of the Polychaetous Annelid Neanthes arenaceodentata before and after Spawning

    KAUST Repository

    Chandramouli, Kondethimmanahalli


    The Neanthes acuminata species complex (Polychaeta) are cosmopolitan in distribution. Neanthes arenaceodentata, complex, has been widely used as toxicological test animal in the marine environment. Method of reproduction is unique in this polychaete complex. Same sexes fight and opposite sexes lie side by side until egg laying. Females lose about 75% of their weight and die after laying eggs. The male, capable of reproducing up to nine times, fertilizes the eggs and incubates the embryos for 3-4 weeks. The objective of this study was to determine if there is any set of proteins that influences this unique pattern of reproduction. Gel-based two-dimensional electrophoresis (2-DE) and gel-free quantitative proteomics methods were used to identify differential protein expression patterns before and after spawning in both male and female N. arenaceodentata. Males showed a higher degree of similarity in protein expression patterns but females showed large changes in phosphoproteme before and after spawning. There was a decrease (about 70%) in the number of detected phosphoproteins in spent females. The proteins involved in muscular development, cell signaling, structure and integrity, and translation were differentially expressed. This study provides proteomic insights of the male and female worms that may serve as a foundation for better understanding of unusual reproductive patterns in polychaete worms. © 2013 Chandramouli et al.

  20. The making of a branching annelid: an analysis of complete mitochondrial genome and ribosomal data of Ramisyllis multicaudata


    M. Teresa Aguado; Glasby, Christopher J.; Schroeder, Paul C.; Anne Weigert; Christoph Bleidorn


    Ramisyllis multicaudata is a member of Syllidae (Annelida, Errantia, Phyllodocida) with a remarkable branching body plan. Using a next-generation sequencing approach, the complete mitochondrial genomes of R. multicaudata and Trypanobia sp. are sequenced and analysed, representing the first ones from Syllidae. The gene order in these two syllids does not follow the order proposed as the putative ground pattern in Errantia. The phylogenetic relationships of R. multicaudata are discerned using a...

  1. Has .i.Tilia x euchlora./i. a detrimental effect on soil annelids in urban greens?

    Czech Academy of Sciences Publication Activity Database

    Schlaghamerský, J.; Khodabocus, J.B.; Pižl, Václav

    České Budějovice: Institute of Soil Biology BC AS CR, 2009, s. 141-145. ISBN 978-80-86525-13-6. [Contributions to Soil Zoology in Central Europe III. Central European Workshop on Soil Zoology /9./. České Budějovice (CZ), 17.04.2007-20.04.2007] R&D Projects: GA AV ČR IAA600660608 Institutional research plan: CEZ:AV0Z60660521 Keywords : Lumbricidae * Enchytraeidae * urban ecology Subject RIV: EH - Ecology, Behaviour

  2. Gamma-aminobutyric acid and 5-hydroxytryptamine in the nervous system of an annelid worm (Nereis diversicolor)

    International Nuclear Information System (INIS)

    Autoradiographic techniques have been employed to define the cellular elements involved in the elaboration of gamma-aminobutyric acid (GABA) and 5-hydroxytryptamine (5-HT) in the nervous system of Nereis. This procedure is described. Results concerning the distribution of 5-HT and GABA in Nereis are still incomplete. Nevertheless, as a result of these initial autoradiographic data, it seems possible to postulate an effect of 5-HT and GABA in the neuropil and in the peripheral nerves. 5-HT would also act in certain endplates located in the pharynx of Nereis, for instance. This monoamine, however, probably does not act the level of the infracerebral complex

  3. Spermatogenesis in Nereis diversicolor O.F. Mueller (Annelid Polychete) morphologic and autoradiographic study of nuclear evolution

    International Nuclear Information System (INIS)

    The evolution of nuclear structure was related to DNA and RNA syntheses, visualized by high resolution autoradiography. In spermatogonia, the nucleus shows chromatin clumps, irregular in shape and size. At this stage, 3H-uridine and 3H-thymidine incorporation is very low. In premeiotic interphase spermatocytes, a typical nuclear evolution is found. During the G1 period, chromatin strands constitute a regular reticulum. Autoradiography performed at this stage indicates a huge increase in RNA synthesis. During the S period, chromatin undergoes extensive dispersion. The G2 period seems to be marked by nucleolar regression and decrease in RNA synthesis. The possible relation between increase of RNA synthesis at premeiotic interphase and the differentiation of meiotic cells is discussed

  4. An experimental study of the retention of zinc 65 by sediment and polychaete annelids (Nereis diversicolor Muller)

    International Nuclear Information System (INIS)

    Zinc 65 is a radionuclide with an intermediate half-life (245 days). It is an isotope of a biological trace element which can be found in some liquid wastes released by nuclear facilities. The first part of the paper concerns zinc 65 transfer from water to sediment. This process is essentially characterised by its rapidity and intensity. After 48 hours water loses 50% of its activity and transfer reaches 100% beyond the 20th day. Zinc 65 is strongly bound to the sediment and its desorption is almost non-existent. The second part reports the results about zinc 65 contamination of Nereis diversicolor, a species which can be considered as a vehicle of recirculation for the radionuclide fixed in the sediment. This assumption is partly verified although zinc 65 accumulation by Nereis diversicolor from water is 20 times more important than from sediment

  5. Susceptibility to Heavy Metals and Characterization of Heterotrophic Bacteria Isolated from Two Hydrothermal Vent Polychaete Annelids, Alvinella pompejana and Alvinella caudata


    Jeanthon, Christian; Prieur, Daniel


    Specimens of alvinellid polychaetes and their tubes were collected in the Parigo hydrothermal vent field on the East Pacific Rise (13°N) in October and November 1987. Heterotrophic bacterial strains were isolated on metal-amended media from the tube and dorsal integument of one specimen of Alvinella pompejana, from the dorsal integument of another from the whole integument of a specimen of Alvinella caudata, and from undetermined alvinellid tubes. The strains were characterized and tested for...

  6. Investigation by electrospray ionization mass spectrometry of the extracellular hemoglobin from the polychaete annelid Alvinella pompejana: an unusual hexagonal bilayer hemoglobin. (United States)

    Zal, F; Green, B N; Lallier, F H; Toulmond, A


    Alvinella pompejana inhabits deep-sea hydrothermal vent sites along the East-Pacific Rise, where it colonizes the walls of actively venting high-temperature chimneys. This worm is the most thermophilic metazoan known to date. In Alvinella, as in other alvinellids, oxygen transport is mainly achieved by an extracellular Hb dissolved in the vascular blood. This Hb has a molecular mass of 3833 +/- 14 kDa as revealed by multiangle laser light scattering (MALLS). Native and derivative Hb (reduced, carbamidomethylated, and deglycosylated) were analyzed by electrospray ionization mass spectrometry (ESI-MS). The data were processed by the maximum entropy deconvolution system (MaxEnt). We identified three groups of peaks for Alvinella Hb, at ca. 16, 23-26, and 50 kDa corresponding to (i) four monomeric globin chains, a1 (16 633.4), a2(16 532.4), a3 (16 419.6), and a4(16 348.9); (ii) four linker chains, L1-L4 (22 887. 1, 24 230.5, 26 233.6, and 25 974.4); and (iii) one disulfide-bonded trimer T (51 431.9) composed of globin chains b (16 477.5), c (16 916.1), and d (18 048.8). These Hbs were also subjected to SDS-PAGE analysis for comparative purposes. In addition, using the ESI-MS data we propose two alternative models for the quaternary structure of Alvinella's Hb. PMID:9305968


    Institute of Scientific and Technical Information of China (English)

    张希春; 孙振钧; 高锦; 侯全民; 林桂秋; 禚如朋


    经硫酸铵沉淀、超滤和阳离子交换分离,得到了一蚯蚓抗菌肽EABP-1,该肽的最大紫外吸收在277.16 nm,SDS-PAGE结果表明其Mr≈ 20×103,精确的分子量没有确定.最小抑菌浓度(ρMIC)实验表明,EABP-1对鹑鸡肠球菌(Enterococcus gallinarum)、绿脓杆菌(Pseudomonas pyocyanea)、鲍氏不动(Acinetobacter baumanii)、土生克雷伯(Klebsiella terrigena)的ρMIC为11.4 μg/mL,对粪肠球菌(Enterococcus faecalis)的ρMIC为 22.8 μg/mL, 对真菌白色念株菌(Candida albicans)没有表现为完全的抑制作用.

  8. Do artificial structures alter marine invertebrate genetic makeup?


    Fauvelot, Cecile; Costantini, Federica; Virgilio, Massimiliano; Abbiati, Marco


    Human-made structures are increasingly built in marine coastal habitats for a variety of purposes. Offshore oil and gas production platforms are among the largest examples. Yet, biological effects of these increasing density artificial substrata are under evaluated. The objective of our study is to investigate the possible role of offshore platforms in modifying the genetic composition of populations of natural rocky shores species. The serpulid Pomatoceros triqueter was used as a model, and ...

  9. Regeneration and calcification in the Spirobranchus lamarcki operculum: development and comparative genetics of a novel appendage


    Szabó, Réka


    Regeneration, the replacement of lost or damaged body parts, and biomineralisation, the biologically controlled formation of minerals, are important and widespread abilities in the animal kingdom. Both phenomena have a complex evolutionary history; thus their study benefits from investigations in diverse animals. Spirobranchus (formerly Pomatoceros) lamarcki is a small tube-dwelling polychaete worm of the serpulid family. Serpulids have evolved a novel head appendage, the operculum, which fun...

  10. A study on the Gut contents of six Leathery Turtles Dermochelys Coriacea (Linnaeus) (Reptilia: Testudines: Dermochelyidae) from British waters and from the Netherlands


    Hartog, den, P.R.; Nierop, van, H.


    Microscopical investigations of the gut contents of six individuals of Dermochelys coriacea from southern England and the North Sea revealed the presence in all of these of numerous nematocysts, mainly scyphozoan. Only six species of Scyphozoa occur in British shallow waters and in the North Sea, viz., Pelagia noctiluca (Forskål), Chrysaora hysoscella (L.), Aurelia aurita (L.), Cyanea capillata (L.), C. lamarckii (L.) and Rhizostoma octopus (L.). For the purpose of comparison and identificati...

  11. Mangrove hybrid of Rhizophora and its parental species in Indo-Malayan region

    Directory of Open Access Journals (Sweden)



    Full Text Available Setyawan AD, Ulumuddin YI, Ragavan P. 2014. Mangrove hybrid of Rhizophora and its parental species in Indo-Malayan region. Nusantara Bioscience 6: 69-81. There was two putative hybrid species of mangrove in the Indo-Malayan region, namely Rhizophora x annamalayana Kathir. and R. x lamarckii Montrouz. Rhizophora x annamalayana is most recently known as a natural hybrid between R. apiculata and R. mucronata. At first, this plant is considered as R. x lamarckii, a well-known mangrove hybrid between R. apiculata and R. stylosa. Since R. stylosa is not distributed in India and Sri Lanka, the location where this species was firstly discovered, the name of the new hybrid species between R. apiculata and R. mucronata was corrected. Meanwhile, R. x lamarckii has long been known and is always found in habitat where its parents grew. Besides, the cross breeding of R. mucronata and R. stylosa has never been reported. Both are sibling species that have identical morphological characteristics, thus the hybrid cross-bred species was not observed visually and can only be distinguished through genetic studies.

  12. Species diversity of Rhizophora in Tambelan Islands, Natuna Sea, Indonesia

    Directory of Open Access Journals (Sweden)



    Full Text Available Research on diversity and distribution of mangroves on the small remote islands are rarely performed than on the coastal area and estuaries. Tambelan Islands is a cluster of small islands isolated in the Natuna Sea, Indonesia. On the island there are four species of Rhizophora, namely R. apiculata, R. stylosa, R. mucronata, and hybrid species R. x lamarckii. Rhizophora stylosa and R. apiculata are the most common species found. R. mucronata only found in certain places (i.e. Durian River, R. x lamarckii rare, usually grows in stands that also covered by the two parental, R. stylosa and R. apiculata. All Rhizophora species were found to have thorn on the leaf tip, and spotted brown on the underneath leaf. R. apiculata has a petal without woolly feathers, inflorescence have short stalks and cork. R. stylosa and R. mucronata are sibling species, both of them have a long-stalks and dichotomy inflorescence, but the style of R. mucronata very short ( 2.5 mm. R. x lamarckii has characters between R. apiculata and R. stylosa.

  13. Anelídeos poliquetas da plataforma continental norte do Estado de São Paulo: I - Padrões de densidade e diversidade específica Polychaetous annelids of the northern continental shelf of São Paulo State: I - Patterns of density and specific diversity


    Paulo Cesar de Paiva


    Foram estudados os padrões de densidade e diversidade específica dos anelídeos poliquetas da plataforma continental norte do Estado de São Paulo. A densidade de poliquetas foi maior na plataforma interna, especialmente na radial Sul. Nas radiais Central e Norte foram observadas variações temporais nas isóbatas de 20 e 35 m, com valores maiores no verão. Os valores de diversidade específica foram preponderantemente mais baixos na plataforma externa, no verão, e altos, no inverno, enquanto a pl...

  14. Comparative neuroanatomy suggests repeated reduction of neuroarchitectural complexity in Annelida

    Directory of Open Access Journals (Sweden)

    Todt Christiane


    Full Text Available Abstract Background Paired mushroom bodies, an unpaired central complex, and bilaterally arranged clusters of olfactory glomeruli are among the most distinctive components of arthropod neuroarchitecture. Mushroom body neuropils, unpaired midline neuropils, and olfactory glomeruli also occur in the brains of some polychaete annelids, showing varying degrees of morphological similarity to their arthropod counterparts. Attempts to elucidate the evolutionary origin of these neuropils and to deduce an ancestral ground pattern of annelid cerebral complexity are impeded by the incomplete knowledge of annelid phylogeny and by a lack of comparative neuroanatomical data for this group. The present account aims to provide new morphological data for a broad range of annelid taxa in order to trace the occurrence and variability of higher brain centers in segmented worms. Results Immunohistochemically stained preparations provide comparative neuroanatomical data for representatives from 22 annelid species. The most prominent neuropil structures to be encountered in the annelid brain are the paired mushroom bodies that occur in a number of polychaete taxa. Mushroom bodies can in some cases be demonstrated to be closely associated with clusters of spheroid neuropils reminiscent of arthropod olfactory glomeruli. Less distinctive subcompartments of the annelid brain are unpaired midline neuropils that bear a remote resemblance to similar components in the arthropod brain. The occurrence of higher brain centers such as mushroom bodies, olfactory glomeruli, and unpaired midline neuropils seems to be restricted to errant polychaetes. Conclusions The implications of an assumed homology between annelid and arthropod mushroom bodies are discussed in light of the 'new animal phylogeny'. It is concluded that the apparent homology of mushroom bodies in distantly related groups has to be interpreted as a plesiomorphy, pointing towards a considerably complex


    The chronic effects of the herbicide diuron on survival and reproduction of Daphnia pulex, and survival and growth of the amphipod Hyalella azteca, the midge Chironomus tentans, juvenile and embro/larval fathead minnows, Pimephales promelas, annelid worms, Lumbriculus variegatus,...

  16. Cellular and muscular growth patterns during sipunculan development

    DEFF Research Database (Denmark)

    Kristof, Alen; Wollesen, Tim; Maiorova, Anastassya S; Wanninger, Andreas

    Sipuncula is a lophotrochozoan taxon with annelid affinities, albeit lacking segmentation of the adult body. Here, we present data on cell proliferation and myogenesis during development of three sipunculan species, Phascolosoma agassizii, Thysanocardia nigra, and Themiste pyroides. The first...

  17. Timing and Scope of Genomic Expansion within Annelida: Evidence from Homeoboxes in the Genome of the Earthworm Eisenia fetida


    Zwarycz, Allison S.; Nossa, Carlos W.; Putnam, Nicholas H; Ryan, Joseph F.


    Annelida represents a large and morphologically diverse group of bilaterian organisms. The recently published polychaete and leech genome sequences revealed an equally dynamic range of diversity at the genomic level. The availability of more annelid genomes will allow for the identification of evolutionary genomic events that helped shape the annelid lineage and better understand the diversity within the group. We sequenced and assembled the genome of the common earthworm, Eisenia fetida. As ...

  18. An Early Cambrian problematic fossil: Vetustovermis and its possible affinities


    Chen, Jun-Yuan; Huang, Di-Ying; Bottjer, David J.


    The Early Cambrian problematic fossil Vetustovermis (Glaessner 1979 Alcheringa 3, 21–31) was described as an annelid or arthropod. Anatomical analysis of 17 new specimens from the Lower Cambrian Maotianshan Shale at Anning, Kunming (South China) does not support its affinities with annelids or arthropods. Anatomical features instead resemble other animal groups including modern flatworms, nemertines and molluscs. The presence of a pelagic slug-like form and ventral foot, as well as a head wit...

  19. Inversion of the chordate body axis: are there alternatives? (United States)

    Gerhart, J.


    One major morphological difference between chordates and annelids or arthropods is the opposite orientation of the nerve cord and heart. A long-standing proposal is that the chordate axis evolved by inverting the body of an ancestor with the annelid/arthropod orientation. However, the data can also be explained by a common ancestor with diffuse dorsoventral organization, followed by oppositely directed condensation of the nerve cord and relocation of the heart in the two lines.

  20. Inversion of the chordate body axis: Are there alternatives?


    Gerhart, J.


    One major morphological difference between chordates and annelids or arthropods is the opposite orientation of the nerve cord and heart. A long-standing proposal is that the chordate axis evolved by inverting the body of an ancestor with the annelid/arthropod orientation. However, the data can also be explained by a common ancestor with diffuse dorsoventral organization, followed by oppositely directed condensation of the nerve cord and relocation of the heart in the t...

  1. Pollen morphology of Rhizophora L. in Peninsular Malaysia

    Energy Technology Data Exchange (ETDEWEB)

    Mohd-Arrabe' , A. B.; Noraini, Talip Noraini [School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)


    Rhizophora L. are common mangrove genus in Peninsular Malaysia, it contains 3 species and 1 hybrid (R. apiculata Blume, R. mucronata Lam., R. stylosa Griff., R. x lamarckii Montrouz). This genus has some unique adaptation towards extreme environment. Rhizophora has looping aerial stilt-root and uniformly viviparous. The aim of this study is to investigate the variation in the pollen morphology of Rhizophora that can be related to their habitat. Methods include in this study is pollen observation under light and acetolysis method under scanning electron microscope. Pollen type of Rhizophora species studied except hybrid species is classified tricolporate, shape spheroidal based on ratio of length polar axis/ length of equatorial axis (1.03 - 1.09). The exine ornamentation is perforate-reticulate for R. apiculata and R. mucronata, while R. stylosa is perforate. For the only hybrid in Peninsular Malaysia, R. x lamarckii (R. apiculata x R. stylosa) differs from others, tricolpate with the absence of porate, shape is subprolate and exine ornamentation is reticulate and striate in equatorial region. Pollenkitt is present due to the salty and extreme environment. This may enhance the volume of pollenkitt present surrounding the pollen grains in Rhizophora for protection and adaptation purposes. Based on these findings, it is evident that pollen morphology is somehow related to its natural habitat.

  2. Six3

    Directory of Open Access Journals (Sweden)

    Steinmetz Patrick RH


    Full Text Available Abstract Background The heads of annelids (earthworms, polychaetes, and others and arthropods (insects, myriapods, spiders, and others and the arthropod-related onychophorans (velvet worms show similar brain architecture and for this reason have long been considered homologous. However, this view is challenged by the 'new phylogeny' placing arthropods and annelids into distinct superphyla, Ecdysozoa and Lophotrochozoa, together with many other phyla lacking elaborate heads or brains. To compare the organisation of annelid and arthropod heads and brains at the molecular level, we investigated head regionalisation genes in various groups. Regionalisation genes subdivide developing animals into molecular regions and can be used to align head regions between remote animal phyla. Results We find that in the marine annelid Platynereis dumerilii, expression of the homeobox gene six3 defines the apical region of the larval body, peripherally overlapping the equatorial otx+ expression. The six3+ and otx+ regions thus define the developing head in anterior-to-posterior sequence. In another annelid, the earthworm Pristina, as well as in the onychophoran Euperipatoides, the centipede Strigamia and the insects Tribolium and Drosophila, a six3/optix+ region likewise demarcates the tip of the developing animal, followed by a more posterior otx/otd+ region. Identification of six3+ head neuroectoderm in Drosophila reveals that this region gives rise to median neurosecretory brain parts, as is also the case in annelids. In insects, onychophorans and Platynereis, the otx+ region instead harbours the eye anlagen, which thus occupy a more posterior position. Conclusions These observations indicate that the annelid, onychophoran and arthropod head develops from a conserved anterior-posterior sequence of six3+ and otx+ regions. The six3+ anterior pole of the arthropod head and brain accordingly lies in an anterior-median embryonic region and, in consequence, the optic

  3. Uptake of curium (244Cm) by five benthic marine species (Arenicola marina, Cerastoderma edule, Corophium volutator, Nereis diversicolor and Scrobicularia plana): comparison with americium and plutonium

    International Nuclear Information System (INIS)

    Curium (244Cm) uptake from contaminated sea water was studied in five benthic marine species: two bivalve molluscs (Scrobicularia plana and Cerastoderma edule), two polychaete annelids (Arenicola marina and Nereis diversicolor) and one amphidpod crustacean (Corophium volutator). The concentrations in the whole organisms relative to the concentration in the sea water (concentration factors) were: 700 for the amphipods (after 11 d of accumulation), 140 for the cockles (after 28 d), 80 for the scrobicularia (after 23d) and approx. 30 for the two annelids (after > 20 d). All species except S. plana accumulated americium and curium similarly; S. plana accumulated similar amounts of curium and plutonium. (author)

  4. Uptake of curium (/sup 244/Cm) by five benthic marine species (Arenicola marina, Cerastoderma edule, Corophium volutator, Nereis diversicolor and Scrobicularia plana): comparison with americium and plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Miramand, P.; Germain, P.; Arzur, J.C.


    Curium (/sup 244/Cm) uptake from contaminated sea water was studied in five benthic marine species: two bivalve molluscs (Scrobicularia plana and Cerastoderma edule), two polychaete annelids (Arenicola marina and Nereis diversicolor) and one amphidpod crustacean (Corophium volutator). The concentrations in the whole organisms relative to the concentration in the sea water (concentration factors) were: 700 for the amphipods (after 11 d of accumulation), 140 for the cockles (after 28 d), 80 for the scrobicularia (after 23d) and approx. 30 for the two annelids (after > 20 d). All species except S. plana accumulated americium and curium similarly; S. plana accumulated similar amounts of curium and plutonium.

  5. Terebella lapilloides Münster, 1833 from the Upper Jurassic-Lower Cretaceous İnaltı carbonates, northern Turkey: its taxonomic position and paleoenvironmental-paleoecological significance


    KAYA, Mustafa Yücel; ALTINER, Demir


    The agglutinating annelid Terebella lapilloides Münster, 1833 is commonly encountered in reefal deposits from the Late Jurassic. This annelid is described and documented for the first time from the Upper Jurassic-Lower Cretaceous carbonates of the İnaltı Formation in the Central Pontides, Turkey. The whole İnaltı formation, 395 m in thickness, was studied near Bürnük village and 105 samples were collected along the section. The investigated thin sections reveal the shallow water and the reefa...

  6. The phylogenetic odyssey of the erythrocyte. II. The early or invertebrate prototypes


    Glomski, Chester A.; Tamburlin, Judith


    Freely existing hemoglobin-bearing cells suspended in a plasmic milieu (erythrocytes) are found in a relatively small number of taxanomically scattered invertebrates. These species include some annelids, echiurids, molluscs, phoronids, nemerteans and echinoderms, e.g. Pista pacifica, Urechis caupo, Noetia ponderosa, Phoronis australis, Lineus fuscoviridis and Cucumaria miniata respectively. The typical invertebrate erythrocyte (hemocyte, coelomocyte) can be des...

  7. Why do Oystercatchers Haematopus ostralegus switch from feeding on Baltic tellin Macoma balthica to feeding on the ragworm Nereis diversicolor during the breeding season?

    NARCIS (Netherlands)

    Bunskoeke, EJ; Ens, BJ; Hulscher, JB; DeVlas, SJ


    Oystercatchers Haematopus ostralegus breeding on the isle of Schiermonnikoog in the Dutch Wadden Sea: switched from a diet dominated by the bivalve Macoma balthica in late spring to a diet dominated by the annelid worm Nereis diversicolor in early summer. Although all Oystercatchers switched, the ti

  8. Neurogenesis suggests independent evolution of opercula in serpulid polychaetes

    DEFF Research Database (Denmark)

    Brinkmann, Nora; Wanninger, Andreas


    BACKGROUND: The internal phylogenetic relationships of Annelida, one of the key lophotrochozoan lineages, are still heavily debated. Recent molecular analyses suggest that morphologically distinct groups, such as the polychaetes, are paraphyletic assemblages, thus questioning the homology of a nu...... neurogenesis provide a novel set of characters that highlight the developmental plasticity of the segmented annelid nervous system....

  9. Environ: E00510 [KEGG MEDICUS

    Lifescience Database Archive (English)

    Full Text Available E00510 Leech Hirudo Crude drug Hirudin Hirudo nipponia [TAX:42736], Whitmania pigra... [TAX:486152], Whitmania acranulata, Whitmania [TAX:307843] Hirudidae Hirudo nipponia, Whitmania pigra, Whitmania acranulata Crude drugs [BR:br08305] Animals Annelids E00510 Leech ...

  10. Evolution of cave Axiokebuita and Speleobregma (Scalibregmatidae, Annelida)

    DEFF Research Database (Denmark)

    Martinez Garcia, Alejandro; Di Domenico, Maikon; Worsaae, Katrine


    The evolutionary history of Axiokebuita and Speleobregma, two poorly known lineages of annelids exclusive from deep-sea or marine caves but always from crevicular habitats, is explored here. Speleobregma lanzaroteum Bertelsen, 1986, and Axiokebuita cavernicola sp. n. are described from anchialine...

  11. Molecular identification of differentially regulated genes in the hydrothermal-vent species Bathymodiolus thermophilus and Paralvinella pandorae in response to temperature

    Directory of Open Access Journals (Sweden)

    Shillito Bruce


    Full Text Available Abstract Background Hydrothermal vents and cold seeps represent oases of life in the deep-sea environment, but are also characterized by challenging physical and chemical conditions. The effect of temperature fluctuations on vent organisms in their habitat has not been well explored, in particular at a molecular level, most gene expression studies being conducted on coastal marine species. In order to better understand the response of hydrothermal organisms to different temperature regimes, differentially expressed genes (obtained by a subtractive suppression hybridization approach were identified in the mussel Bathymodiolus thermophilus and the annelid Paralvinella pandorae irlandei to characterize the physiological processes involved when animals are subjected to long term exposure (2 days at two contrasting temperatures (10° versus 20°C, while maintained at in situ pressures. To avoid a potential effect of pressure, the experimental animals were initially thermally acclimated for 24 hours in a pressurized vessel. Results For each species, we produced two subtractive cDNA libraries (forward and reverse from sets of deep-sea mussels and annelids exposed together to a thermal challenge under pressure. RNA extracted from the gills, adductor muscle, mantle and foot tissue were used for B. thermophilus. For the annelid model, whole animals (small individuals were used. For each of the four libraries, we sequenced 200 clones, resulting in 78 and 83 unique sequences in mussels and annelids (about 20% of the sequencing effort, respectively, with only half of them corresponding to known genes. Real-time PCR was used to validate differentially expressed genes identified in the corresponding libraries. Strong expression variations have been observed for some specific genes such as the intracellular hemoglobin, the nidogen protein, and Rab7 in P. pandorae, and the SPARC protein, cyclophilin, foot protein and adhesive plaque protein in B. thermophilus

  12. Variable intron/exon structure in the oligochaete lombricine kinase gene. (United States)

    Doumen, Chris


    Lombricine kinase is an annelid enzyme that belongs to the phosphagen kinase family of which creatine kinase and arginine kinase are the typical representatives. The enzymes play important roles in the cellular energy metabolism of animals. Biochemical, physiological and molecular information with respect to lombricine kinase is limited compared to other phosphagen kinases. This study presents data on the cDNA sequences of lombricine kinase from two smaller oligochaetes, Enchytraeus sp. and Stylaria sp. The deduced amino acid sequences are analyzed and compared with other selected phosphagen kinases. The intron/exon structure of the lombricine kinase gene was determined for these two species as well as two additional oligochaetes, Lumbriculus variegatus and Tubifex tubifex, and compared with available data for annelid phosphagen kinases. The data indicate the existence of a variable organization of the proposed 8-intron/9-exon gene structure. The results provide further insights in the evolution and position of these enzymes within the phosphagen kinase family. PMID:22705027

  13. 陸奥湾におけるマクロベントスの時空間分布


    高橋, 豊美; 前田, 辰昭; 中谷, 敏邦; 柳川, 延之


    In order to elucidate the conditions of food environments for righteye flounders Limanda herzensteini and L. yokohamae in Mutsu Bay, Aomori Prefecture, the distributions of macrobenthos were investigated by analyzing grab samples obtained at approximately 300 stations chiefly from March 1980 to February 1983. Faunal composition in the bay was correlated with the mud contents in the bottom sediments. In the extensive mud bottom in offshore area polychaete annelids predominated, representing 82...

  14. Phylogeny of Myzostomida (Annelida) and their relationships with echinoderm hosts


    Summers, Mindi M; Rouse, Greg W.


    Background Myzostomids are marine annelids, nearly all of which live symbiotically on or inside echinoderms, chiefly crinoids, and to a lesser extent asteroids and ophiuroids. These symbionts possess a variety of adult body plans and lifestyles. Most described species live freely on the exterior of their hosts as adults (though starting life on the host inside cysts), while other taxa permanently reside in galls, cysts, or within the host’s mouth, digestive system, coelom, or gonads. Myzostom...

  15. Multidisciplinary study of trophic diversity and functional role of amphipod crustaceans associated to Posidonia oceanica meadows


    Michel, Loïc


    Posidonia oceanica is the most abundant seagrass of the Mediterranean Sea. It can cover extensive areas with monospecific formations, called meadows. These meadows, whose extent is estimated to about 40,000 km2, are critical features of the Mediterranean coastal zones. Moreover, they shelter important biomass and biodiversity of vagile invertebrates. Among these invertebrates, amphipod crustaceans are, alongside gastropod mollusks and polychaete annelids, one of the dominant groups. Amphip...

  16. Fossil traces of the bone-eating worm Osedax in early Oligocene whale bones


    Kiel, Steffen; Goedert, James L; Kahl, Wolf-Achim; Rouse, Greg W.


    Osedax is a recently discovered group of siboglinid annelids that consume bones on the seafloor and whose evolutionary origins have been linked with Cretaceous marine reptiles or to the post-Cretaceous rise of whales. Here we present whale bones from early Oligocene bathyal sediments exposed in Washington State, which show traces similar to those made by Osedax today. The geologic age of these trace fossils (∼30 million years) coincides with the first major radiation of whales, consistent wit...

  17. Osedax borings in fossil marine bird bones


    Kiel, Steffen; Kahl, Wolf-Achim; Goedert, James


    The bone-eating marine annelid Osedax consumes mainly whale bones on the deep-sea floor, but recent colonization experiments with cow bones and molecular age estimates suggesting a possible Cretaceous origin of Osedax indicate that this worm might be able grow on a wider range of substrates. The suggested Cretaceous origin was thought to imply that Osedax could colonize marine reptile or fish bones, but there is currently no evidence that Osedax consumes bones other than those of mammals. We ...

  18. [Determination of apparent mean mass of proteins associated with heme in the hemoglobin molecule of Arenicola marina (L.), Annelida, Polychaeta]. (United States)

    Toulmond, A


    Protein and iron concentrations and maximum combined oxygen concentration were measured in the blood of the lugworm Arenicola marina. The calculated mean molecular mass of the heme-associated proteins was higher than that reported for known invertebrate and vertebrate intracellular hemoglobins. The difference is probably due to the presence of polypeptide chains not linked to heme groups in the extracellular annelid hemoglobins. PMID:111865

  19. Image analysis platforms for exploring genetic and neuronal mechanisms regulating animal behavior


    Asadulina, Albina


    An important aim of neuroscience is to understand how gene interactions and neuronal networks regulate animal behavior. The larvae of the marine annelid Platynereis dumerilii provide a convenient system for such integrative studies. These larvae exhibit a wide range of behaviors, including phototaxis, chemotaxis and gravitaxis and at the same time exhibit relatively simple nervous system organization. Due to its small size and transparent body, the Platynereis larva is compatible with whole-b...

  20. On the Temperature Behavior of Pulse Propagation and Relaxation in Worms, Nerves and Gels


    Christian Fillafer; Schneider, Matthias F.


    The effect of temperature on pulse propagation in biological systems has been an important field of research. Environmental temperature not only affects a host of physiological processes e.g. in poikilotherms but also provides an experimental means to investigate the thermodynamic phenomenology of nerves and muscle. In the present work, the temperature dependence of blood vessel pulsation velocity and frequency was studied in the annelid Lumbriculus variegatus. The pulse velocity was found to...

  1. The nucleotide sequences of 5S rRNAs from a sea-cucumber, a starfish and a sea-urchin.


    Ohama, T; Hori, H; Osawa, S


    The nucleotide sequences of 5S rRNA from three echinoderms, a sea-cucumber Stichopus oshimae, a starfish Asterina pectinifera and a sea-urchin Hemicentrotus pulcherrimus have been determined. These 5S rRNAs are all 120 nucleotides long. The echinoderm sequences are more related to the sequences of proterostomes animals such as mollusc, annelids and some others (87% identity on average) than to those of vertebrates (82% identity on average).

  2. Origin of the metazoan phyla: Molecular clocks confirm paleontological estimates


    Ayala, Francisco José; Rzhetsky, Andrey; Ayala, Francisco J.


    The time of origin of the animal phyla is controversial. Abundant fossils from the major animal phyla are found in the Cambrian, starting 544 million years ago. Many paleontologists hold that these phyla originated in the late Neoproterozoic, during the 160 million years preceding the Cambrian fossil explosion. We have analyzed 18 protein-coding gene loci and estimated that protostomes (arthropods, annelids, and mollusks) diverged from deuterostomes (echinoderms and chordates) about 670 milli...

  3. Phylogenomic analyses of lophophorates (brachiopods, phoronids and bryozoans) confirm the Lophotrochozoa concept


    Helmkampf, Martin; Bruchhaus, Iris; Hausdorf, Bernhard


    Based on embryological and morphological evidence, Lophophorata was long considered to be the sister or paraphyletic stem group of Deuterostomia. By contrast, molecular data have consistently indicated that the three lophophorate lineages, Ectoprocta, Brachiopoda and Phoronida, are more closely related to trochozoans (annelids, molluscs and related groups) than to deuterostomes. For this reason, the lophophorate groups and Trochozoa were united to Lophotrochozoa. However, the relationships of...

  4. Alvinella pompejana gen. sp. nov., Ampharetidae aberrant des sources hydrothermales de la ride Est-Pacifique


    Desbruyeres, Daniel; Laubier, Lucien


    Several unknown animal forms have recently been collected in the immediate vicinity of hot hydrothermal vents in the Eastern Pacific Ocean, forming a flourishing community of organisms. A tubicolous polychaete builds parchment like tubes around some of the hydrothermal vents. The tubes are covered with particles of metallic sulfur. This annelid is a new species, and is called Alvinella pompejana, new genus and species. The new sub-family Alvinellinae, erected to contain this new species, can ...

  5. Early development of the aplacophoran mollusc Chaetoderma

    DEFF Research Database (Denmark)

    Nielsen, Claus; Haszprunar, Gerhard; Ruthensteiner, Bernhard; Wanninger, Andreas Wilhelm Georg


    The early development of the trochophore larva of the aplacophoran Chaetoderma nitidulum (Mollusca: Caudofoveata = Chaetodermomorpha) is described using scanning and transmission electron microscopy and using fluorescence staining and confocal laser scanning microscopy of the muscle system. The...... early anlagen of the circular body wall muscles does not show the anterior-posterior mode of formation that is typical for annelids, thus strengthening the hypothesis of a non-segmented ancestry of Mollusca....

  6. Leech Therapeutic Applications


    Abdualkader, A. M.; A M Ghawi; M Alaama; Awang, M.; Merzouk, A.


    Hematophagous animals including leeches have been known to possess biologically active compounds in their secretions, especially in their saliva. The blood-sucking annelids, leeches have been used for therapeutic purposes since the beginning of civilization. Ancient Egyptian, Indian, Greek and Arab physicians used leeches for a wide range of diseases starting from the conventional use for bleeding to systemic ailments, such as skin diseases, nervous system abnormalities, urinary and reproduct...

  7. Not whale-fall specialists, Osedax worms also consume fishbones


    Rouse, Greg W.; Goffredi, Shana K.; Johnson, Shannon B.; Vrijenhoek, Robert C.


    Marine annelid worms of the genus Osedax exploit sunken vertebrate bones for food. To date, the named species occur on whale or other mammalian bones, and it is argued that Osedax is a whale-fall specialist. To assess whether extant Osedax species could obtain nutrition from non-mammalian resources, we deployed teleost bones and calcified shark cartilage at approximately 1000 m depth for five months. Although the evidence from shark cartilage was inconclusive, the teleost bones hosted three s...

  8. Cleavage pattern and fate map of the mesentoblast, 4d, in the gastropod Crepidula: a hallmark of spiralian development


    Lyons Deirdre C; Perry Kimberly J; Lesoway Maryna P; Henry Jonathan Q


    Abstract Background Animals with a spiral cleavage program, such as mollusks and annelids, make up the majority of the superphylum Lophotrochozoa. The great diversity of larval and adult body plans in this group emerges from this highly conserved developmental program. The 4d micromere is one of the most conserved aspects of spiralian development. Unlike the preceding pattern of spiral divisions, cleavages within the 4d teloblastic sublineages are bilateral, representing a critical transition...

  9. Alike but different : the evolution of the Tubifex tubifex species complex (Annelida, Clitellata) through polyploidization


    Marotta, R.; A. Crottini; Raimondi, E.; C. Fondello; Ferraguti, M.


    Background Tubifex tubifex is a widespread annelid characterized by considerable variability in its taxonomic characteristics and by a mixed reproductive strategy, with both parthenogenesis and biparental reproduction. In a molecular phylogenetic analysis, we detected substantial genetic variability among sympatric Tubifex spp. from the Lambro River (Milano, Italy), which we suggested comprise several cryptic species. To gain insights into the evolutionary events that generated this different...

  10. Studies on chaetognaths off Ubatuba region, Brazil: II. Feeding habits


    Tsui Hua Liang; Luz Amélia Vega-Pérez


    The diet of chaetognath species were studied by examining the gut contents of 9466 specimens collected off Ubatuba region, São Paulo State. The greatest proportion of chaetognaths (7119 individuals) showed their gut contents empty. Copepods, mollusc eggs, appendicularians, cladocerans and annelids were the most common food items in the gut contents of juveniles and mature stages. Cannibalism occurred in low frequency. In Summer the copepods Temora stylifera and Paracalanus spp were more abund...

  11. Identification and cloning of an invertebrate-type lysozyme from Eisenia andrei

    Czech Academy of Sciences Publication Activity Database

    Josková, Radka; Šilerová, Marcela; Procházková, Petra; Bilej, Martin


    Roč. 33, č. 8 (2009), s. 932-938. ISSN 0145-305X R&D Projects: GA ČR GA206/07/0378; GA ČR GD310/08/H077; GA AV ČR IAA600200704; GA AV ČR KJB500200613 Institutional research plan: CEZ:AV0Z50200510 Keywords : Annelids * Invertebrates * Antimicrobial protein Subject RIV: EC - Immunology Impact factor: 3.290, year: 2009

  12. Cartap poisoning: A rare case report

    Directory of Open Access Journals (Sweden)

    A S Praveen Kumar


    Full Text Available Cartap is a pesticide commonly used to control weevil and caterpillars. It is an analogue of nereistoxin, a neurotoxic substance isolated from the marine annelid Lumbriconereis heteropoda. It causes neuromuscular blockade. Poisoning with cartap is very rare and not yet reported from India. We report a 35-year-old lady with cartap poisoning who presented with nausea, vomiting, and dyspnea. She improved with N-acetyl cysteine and symptomatic management.

  13. Decoding the fossil record of early lophophorates : Systematics and phylogeny of problematic Cambrian Lophotrochozoa


    Butler, Aodhán D.


    The evolutionary origins of animal phyla are intimately linked with the Cambrian explosion, a period of radical ecological and evolutionary innovation that begins approximately 540 Mya and continues for some 20 million years, during which most major animal groups appear. Lophotrochozoa, a major group of protostome animals that includes molluscs, annelids and brachiopods, represent a significant component of the oldest known fossil records of biomineralised animals, as disclosed by the enigmat...

  14. Articulated Wiwaxia from the Cambrian Stage 3 Xiaoshiba Lagerstätte.


    Yang, J.; Smith, M. R.; Lan, T.; Hou, J.-B.; Zhang, X.-G.


    Wiwaxia is a bizarre metazoan that has been interpreted as a primitive mollusc and as a polychaete annelid worm. Extensive material from the Burgess Shale provides a detailed picture of its morphology and ontogeny, but the fossil record outside this lagerstätte is scarce, and complete wiwaxiids are particularly rare. Here we report small articulated specimens of Wiwaxia foliosa sp. nov. from the Xiaoshiba fauna (Cambrian Stage 3, Hongjingshao Formation, Kunming, south China). Although spines ...

  15. Croissance de juvéniles de Nereis diversicolor nourris avec des détritus d'halophytes


    Meziane, T; Retiere, C


    The comparative effect of the uptake of fresh and degraded detritus of halophytic plants, harvested from salt marches of the Mont Saint-Michel Bay (France), on the growth of a juvenile population of the annelid polychaete N. diversicolor (L.) was studied under experimental conditions in summer 1993. Fresh and degraded detritus of Spartina anglica, Halimione portulacoides and Salicornia europeae, as well as the green algae Enteromorpha sp. were distributed separately to homogenous set of juven...

  16. Cycle de développement d'une population intertidale de Nereis virens (Polychaeta Nereidae) de l'estuaire maritime du Saint-Laurent


    Desrosiers, G; Caron, A; Olivier, M; Miron, G


    An intensive study was conducted from 1986 to 1988 to schematize the life history of the intertidal population of the annelid Nereis virens. Spawning occurred between late April and early June on the south shore of the Lower St. Lawrence estuary. Then, epitokous males leave the sediment and move towards female burrows, displaying heteronereid movements before releasing gametes. Femalesremain in their burrow and release oocytes which adhere to sediment surface where they will be fertilized. Al...

  17. Hemoglobins from deep-sea hydrothermal vent scaleworms of the genus Branchipolynoe: a new type of quaternary structure. (United States)

    Hourdez, S; Lallier, F H; Green, B N; Toulmond, A


    Branchipolynoe symmytilida and B. seepensis are two scaleworms (Polychaeta; Polynoidae) living commensally in the mantle cavity of deep-sea hydrothermal vent and cold-seep mussels. In contrast with littoral members of this family, the two species exhibit a large amount of extracellular hemoglobin (Hb) in their coelomic fluid. Gel filtration revealed the existence of four different Hbs: one minor, high molecular mass (3x10(6) Da) Hb, V1-Hb, reminiscent of a vascular hexagonal bilayer annelid Hb; two major coelomic Hbs, C1-Hb, and C2-Hb, with unusual masses for extracellular annelid Hbs of 153 and 124 kDa respectively; and a minor probably coelomic Hb of 23 kDa (C3-Hb). Using electrospray ionization mass spectrometry, SDS-PAGE after subtilisin treatment, and tandem mass spectrometry, we showed that C1-Hb is a trimer of a 57,996 Da chain and C2-Hb is a dimer of a 57,648 Da chain, each chain being a four-domain/four-heme polypeptide. This multimeric, multidomain arrangement is unique among annelid Hbs and appears different from that of other known multidomain Hbs. PMID:10081955

  18. Polychaetes and oligochaetes associated with intertidal rocky shores in a semi-enclosed industrial and urban embayment, with the description of two new species (United States)

    Parapar, Julio; Martínez-Ansemil, Enrique; Caramelo, Carlos; Collado, Rut; Schmelz, Rüdiger


    The species composition and relative abundance of the annelid benthic macrofauna (Polychaeta and Oligochaeta) inhabiting the rocky intertidal zone of the ria of Ferrol (Galicia, NW Spain) were studied during field collections, from 2000 to 2002. A total of 14,619 specimens (11,585 polychaetes belonging to 76 species and 24 families and 3,034 oligochaetes belonging to 18 species and two families) were collected from 98 quantitative samples taken from 13 sampling sites. The general spatial distribution of the annelid fauna reflects an increase of the diversity from the inner to the outer part of the ria. The general patterns found in the annelid composition suggest that the assemblages were dominated by oligochaetes in the inner sheltered sampling sites and polychaetes in the outer more exposed sites. Several faunistical and taxonomical remarks on selected species are presented. Two new species of oligochaetes are described: Coralliodrilus artabrensis sp. n. and Pirodrilus fungithecatus sp. n. (Naididae, Phallodrilinae). A new biological index, based on the oligochaete/polychaete ratio (O/P), is proposed as tool to evaluate environmental quality and to monitor future changes in the environment.

  19. Growth patterns in Onychophora (velvet worms: lack of a localised posterior proliferation zone

    Directory of Open Access Journals (Sweden)

    Landman Kerry A


    Full Text Available Abstract Background During embryonic development of segmented animals, body segments are thought to arise from the so-called "posterior growth zone" and the occurrence of this "zone" has been used to support the homology of segmentation between arthropods, annelids, and vertebrates. However, the term "posterior growth zone" is used ambiguously in the literature, mostly referring to a region of increased proliferation at the posterior end of the embryo. To determine whether such a localised posterior proliferation zone is an ancestral feature of Panarthropoda (Onychophora + Tardigrada + Arthropoda, we examined cell division patterns in embryos of Onychophora. Results Using in vivo incorporation of the DNA replication marker BrdU (5-bromo-2'-deoxyuridine and anti-phospho-histone H3 immunolabelling, we found that a localised posterior region of proliferating cells does not occur at any developmental stage in onychophoran embryos. This contrasts with a localised pattern of cell divisions at the posterior end of annelid embryos, which we used as a positive control. Based on our data, we present a mathematical model, which challenges the paradigm that a localised posterior proliferation zone is necessary for segment patterning in short germ developing arthropods. Conclusions Our findings suggest that a posterior proliferation zone was absent in the last common ancestor of Onychophora and Arthropoda. By comparing our data from Onychophora with those from annelids, arthropods, and chordates, we suggest that the occurrence of a "posterior growth zone" currently cannot be used to support the homology of segmentation between these three animal groups.

  20. Pierisins and CARP-1: ADP-ribosylation of DNA by ARTCs in butterflies and shellfish. (United States)

    Nakano, Tsuyoshi; Takahashi-Nakaguchi, Azusa; Yamamoto, Masafumi; Watanabe, Masahiko


    The cabbage butterfly, Pieris rapae, and related species possess a previously unknown ADP-ribosylating toxin, guanine specific ADP-ribosyltransferase. This enzyme toxin, known as pierisin, consists of enzymatic N-terminal domain and receptor-binding C-terminal domain, or typical AB-toxin structure. Pierisin efficiently transfers an ADP-ribosyl moiety to the N(2) position of the guanine base of dsDNA. Receptors for pierisin are suggested to be the neutral glycosphingolipids, globotriaosylceramide (Gb3), and globotetraosylceramide (Gb4). This DNA-modifying toxin exhibits strong cytotoxicity and induces apoptosis in various human cell lines, which can be blocked by Bcl-2. Pierisin also produces detrimental effects on the eggs and larvae of the non-habitual parasitoids. In contrast, a natural parasitoid of the cabbage butterfly, Cotesia glomerata, was resistant to this toxin. The physiological role of pierisin in the butterfly is suggested to be a defense factor against parasitization by wasps. Other type of DNA ADP-ribosyltransferase is present in certain kinds of edible clams. For example, the CARP-1 protein found in Meretrix lamarckii consists of an enzymatic domain without a possible receptor-binding domain. Pierisin and CARP-1 are almost fully non-homologous at the amino acid sequence level, but other ADP-ribosyltransferases homologous to pierisin are present in different biological species such as eubacterium Streptomyces. Possible diverse physiological roles of the DNA ADP-ribosyltransferases are discussed. PMID:25033755

  1. Classification and evaluation of some endemic plants from Turkey using Grime’s CSR strategies

    Directory of Open Access Journals (Sweden)

    Cengiz Yildirim


    Full Text Available Background: Functional traits play important roles in plant growth and survival. According to functional traits, there are several classification types for plants such as adaptive and demographic strategies. Material and Methods: In this study, eight endemic taxa were collected from the Amasya K�rklar Mountain in Turkey and were classified and evaluated by Grime’s CSR (Competitive, Stress tolerant, Ruderal strategy scheme. Results: These plants are in the LR(lc (Lower risk/least concern red list category and they are hemicryptophytes according to Raunkiaer’s life forms. The CSR strategies of Asyneuma limonifolium subsp. pestalozzae, Digitalis lamarckii, and Paracaryum ancyritanum were CR, Linaria corifolia and Scutellaria salviifolia were CR/CSR, Phlomis armeniaca was C/CR, and Sideritis dichotoma and Jurinea pontica were SC. Conclusions: CR, CR/CSR, and C/CR plants are resistant to competition and disturbance such as grazing, trampling, mowing, soil erosion, and fire, whereas, SC are resistant to competition and stress, for example drought.

  2. Taxonomic Study of Edible Bivalve from Selected Division of Sarawak, Malaysia

    Directory of Open Access Journals (Sweden)

    M.K. Abu Hena


    Full Text Available The diversity of edible bivalve was conducted from August 2010 to July 2011 covering eight divisions i.e., Kuching, Sarikei, Sibu, Mukah, Bintulu, Miri, Limbang and Lawas of Sarawak, Malaysia. Samples were collected from native market and fishing village during the study period. All edible bivalves inhabit either in brackish or marine environment and comprised 19 species from 10 families namely Meretrix meretrix, M. lyrata, Paphia undulata, Circe scripta, Solen regularies, Solen lamarckii, Pharella acutidens, Amusium pleuronectes, Anadara granosa, Pholas orientalis, Gluconome virens, Placuna placenta, Crassotrea lugubris, Isognomon ephippium, Polymesoda erosa, P. bengalensis, P. expansa, Anadonta woodina and Pilsbryoconcha exilis. The diversity of edible bivalves was found highest in Kuching and Bintulu compared to other divisions studied in Sarawak. The bivalve species at Sarawak could have economic potentiality in terms of protein source, livelihoods of local tribes and economic value. Study suggests that if the high conservation and management of edible bivalve diversity could establish in the coastal and wetland area of Sarawak, a remarkable and vast economic return could achieve.

  3. Field experiments on the role of epibenthic predators in determining prey densities in an estuarine mudflat (United States)

    Gee, J. M.; Warwick, R. M.; Davey, J. T.; George, C. L.


    A series of caging experiments was performed on an estuarine mudflat at three seasons of the year, in which Carcinus maenas L. and Pomatoschistus microps (Kroyer) were either excluded from, or allowed to prey upon, the benthos in order to determine to what extent infaunal abundance and mortality was a result of predation by epibenthic predators. The difficulties of conducting and interpreting the results of such experiments are recognized. The benthic macrofauna of this mudflat is dominated numerically by small annelids and there is evidence that adult C. maenas can cause significant increases in the oligochaete component of this assemblage, probably as a result of disturbance caused by its burrowing activity. Juvenile C. maenas on the other hand significantly reduced the abundance of small annelids, particularly the dominant polychaete Manayunkia aestuarina (Bourne) and could be responsible for year-to-year variations in abundance of this species. The role of fish predators (in this case P. microps) is more problematical but it is suggested that in the densities at which they occur naturally on the mudflat they have little direct effect on the abundance of prey species. There is no evidence that seasonal mortality of small annelids is reduced in the absence of predation and this is taken to indicate that not all mortality is due to epibenthic predation. Certain changes in relative abundance of the component species of the harpacticoid copepod community were discerned but it is suggested that the plasticity of their reproductive potential is such that the effect of predation on the group as a whole is usually masked.

  4. Long-term ecological consequences of herbicide treatment to control the invasive grass, Spartina anglica, in an Australian saltmarsh (United States)

    Shimeta, Jeff; Saint, Lynnette; Verspaandonk, Emily R.; Nugegoda, Dayanthi; Howe, Steffan


    Invasive plants acting as habitat modifiers in coastal wetlands can have extensive ecological impacts. Control of invasive plants often relies on herbicides, although little is known about subsequent environmental impacts. Studying effects of herbicides on non-target species and long-term cascading consequences may yield insights into the ecology of invasive species by revealing interactions with native species. We conducted a long-term field experiment measuring effects of treating the invasive saltmarsh grass, Spartina anglica, with the herbicide Fusilade Forte®. No changes in sedimentary macrofaunal abundances or species richness, diversity, or assemblages were detected 1-2 months after spraying, despite known toxicity of Fusilade Forte® to fauna. This lack of impact may have been due to low exposure, since the herbicide was taken up primarily by plant leaves, with the small amount that reached the sediment hydrolyzing rapidly. Six months after spraying, however, total macrofauna in treated plots was more than four times more abundant than in unsprayed control plots, due to a fifteen-fold increase in annelids. This population growth correlated with increased sedimentary organic matter in treated plots, likely due to decomposition of dead S. anglica leaves serving as food for annelids. After another year, no differences in macrofauna or organic matter remained between treatments. The indirect effect on annelid populations from herbicide treatment could benefit management efforts by providing greater food resources for wading birds, in addition to improving birds' access to sediments by reducing plant cover. This study shows that an invasive grass can have a significant impact on native fauna through food-web interactions, influenced by herbicide usage.

  5. Larval nervous systems

    DEFF Research Database (Denmark)

    Nielsen, Claus


    The apical organ of ciliated larvae of cnidarians and bilaterians is a true larval organ that disappears before or at metamorphosis. It appears to be sensory, probably involved in metamorphosis, but knowledge is scant. The ciliated protostome larvae show ganglia/nerve cords that are retained as the...... ‘deuterostomian’ blastopore fates both in an annelid and in a mollusk, which are both placed in families with the ‘normal’ spiralian gastrulation type, and in the chaetognaths demonstrates that the chordate type of gastrulation could easily have evolved from the spiralian type. This indicates that the latest...

  6. Two-dimensional electrophoresis of Arenicola marina extracellular hemoglobin: separation of chains with identical molecular mass but different isoelectric point. (United States)

    Slitine, F E; Toulmond, A


    1. On the basis of their molecular masses, four types of polypeptides (A, B, C, D) were obtained by SDS-PAGE of the extracellular hemoglobin of the polychaete annelid Arenicola marina. 2. On 2-dimensional polyacrylamide gel electrophoresis, the erythrocruorin dissociated into six different types of polypeptide chains; A1, A2, B1, B2, C and D. 3. A1 and B1 migrate in 2-dimensional electrophoresis at the same position as alpha and beta chains of human hemoglobin. PMID:1814687

  7. The mitochondrial genome of the sipunculid Phascolopsis gouldii supports its association with Annelida rather than Mollusca

    Energy Technology Data Exchange (ETDEWEB)

    Boore, Jeffrey L.; Staton, Joseph


    We have determined the sequence of about half (7470 nts) of the mitochondrial genome of the sipunculid Phascolopsis gouldii, the first representative of this phylum to be so studied. All of the 19 identified genes are transcribed from the same DNA strand. The arrangement of these genes is remarkably similar to that of the oligochaete annelid Lumbricus terrestris. Comparison of both the inferred amino acid sequences and the gene arrangements of a variety of diverse metazoan taxa reveals that the phylum Sipuncula is more closely related to Annelida than to Mollusca. This requires reinterpretation of the homology of several embryological features and of patterns of animal body plan evolution.

  8. A new species of myxosporean (Sphaeromyxidae), a parasite of lined seahorses, Hippocampus erectus, from the Gulf of Mexico. (United States)

    Sears, B F; Anderson, P; Greiner, E C


    Sphaeromyxa cannolii sp. n. is described from the bile ducts of aquaria-maintained lined seahorses (Hippocampus erectus) from the Gulf of Mexico. Spores of the new species are linear, 17-18 µm long and 5-6 µm wide, with flattened tips; polar capsules measure 4 × 3 µm. Routine necropsies of H. erectus following planned death revealed liver inflammation, bile duct obstruction, bile accumulation, and myxozoan parasites in the bile ducts of 11 of 40 animals sampled (27.5%). The presence of S. cannolii in an aquaculture setting should prompt keepers to carefully quarantine new animals and exclude annelid fauna, a potential intermediate host of myxozoans. PMID:21506813

  9. Dermal exposure of Eisenia andrei earthworms: Effects of heavy metals on metallothionein and phytochelatin synthase gene expressions in coelomocytes. (United States)

    Homa, Joanna; Rorat, Agnieszka; Kruk, Jerzy; Cocquerelle, Claude; Plytycz, Barbara; Vandenbulcke, Franck


    Parameters such as total number of coelomocytes, riboflavin content in coelomocytes, expression of genes implied in metal homeostasis, and detoxification mechanisms can be used as biomarkers to assess the impact of metals on annelids. Defense biomarkers (detoxification gene expressions and coelomocyte parameters) were investigated in the ecotoxicologically important species Eisenia andrei following in vivo exposure to 5 different metals (zinc, copper, nickel, lead, and cadmium) at known concentrations. Coelomocyte numbers and riboflavin content were not affected by metallic exposure, but metal-specific gene expression variations were evidenced. PMID:25693738

  10. Integrative analysis of polychaete ontogeny: cell proliferation patterns and myogenesis in trochophore larvae of Sabellaria alveolata

    DEFF Research Database (Denmark)

    Brinkmann, Nora; Wanninger, Andreas


    this crucial mesoderm-derived organ system, particularly in indirect developing representatives of the Lophotrochozoa. Here, we document the temporal and spatial patterns of muscle formation and cell proliferation in the polychaete Sabellaria alveolata during planktotrophic larval development in order...... metamerically arranged organ systems in polychaetes. The occurrence of three clusters of proliferating cells in the trunk region of the metatrochophore indicates synchronous subdivision of the larval mesoderm in the first three segments. Assuming a polychaete-like ancestor at the base of the annelid tree...

  11. Megascopic Symmetrical Metazoans from the Ediacaran Doushantuo Formation in the Northeastern Guizhou, South China

    Institute of Scientific and Technical Information of China (English)

    Wang Yue; Wang Xunlian; Huang Yuming


    In South China, various megascopic symmetrical metazoan fossils were found in the upper Doushantuo (陡山沱)Formation of the Neoproterozoic Ediacaran.The worm-like fossil is characterized by modern taxological annelid, for many metameres, parapodia, one possible tentale, an alimentary canal, and a dorsal vessel. The triradiate discoidal fossil is belong to Trilobozoa, and the octaradiate discoidal fossil might be Ctenophora. All these fossils indicate that the megascopic metazoans have appeared in the Doushantuoian of Eidacaran and imply that the symmetrical metazoans must have originated at least 550 Ma ago.

  12. Not all jellyfish are equal: isotopic evidence for inter- and intraspecific variation in jellyfish trophic ecology. (United States)

    Fleming, Nicholas E C; Harrod, Chris; Newton, Jason; Houghton, Jonathan D R


    Jellyfish are highly topical within studies of pelagic food-webs and there is a growing realisation that their role is more complex than once thought. Efforts being made to include jellyfish within fisheries and ecosystem models are an important step forward, but our present understanding of their underlying trophic ecology can lead to their oversimplification in these models. Gelatinous zooplankton represent a polyphyletic assemblage spanning >2,000 species that inhabit coastal seas to the deep-ocean and employ a wide variety of foraging strategies. Despite this diversity, many contemporary modelling approaches include jellyfish as a single functional group feeding at one or two trophic levels at most. Recent reviews have drawn attention to this issue and highlighted the need for improved communication between biologists and theoreticians if this problem is to be overcome. We used stable isotopes to investigate the trophic ecology of three co-occurring scyphozoan jellyfish species (Aurelia aurita, Cyanea lamarckii and C. capillata) within a temperate, coastal food-web in the NE Atlantic. Using information on individual size, time of year and δ (13)C and δ (15)N stable isotope values, we examined: (1) whether all jellyfish could be considered as a single functional group, or showed distinct inter-specific differences in trophic ecology; (2) Were size-based shifts in trophic position, found previously in A. aurita, a common trait across species?; (3) When considered collectively, did the trophic position of three sympatric species remain constant over time? Differences in δ (15)N (trophic position) were evident between all three species, with size-based and temporal shifts in δ (15)N apparent in A. aurita and C. capillata. The isotopic niche width for all species combined increased throughout the season, reflecting temporal shifts in trophic position and seasonal succession in these gelatinous species. Taken together, these findings support previous assertions

  13. Ecosystem relevance of variable jellyfish biomass in the Irish Sea between years, regions and water types (United States)

    Bastian, Thomas; Lilley, Martin K. S.; Beggs, Steven E.; Hays, Graeme C.; Doyle, Thomas K.


    Monitoring the abundance and distribution of taxa is essential to assess their contribution to ecosystem processes. For marine taxa that are difficult to study or have long been perceived of little ecological importance, quantitative information is often lacking. This is the case for jellyfish (medusae and other gelatinous plankton). In the present work, 4 years of scyphomedusae by-catch data from the 2007-2010 Irish Sea juvenile gadoid fish survey were analysed with three main objectives: (1) to provide quantitative and spatially-explicit species-specific biomass data, for a region known to have an increasing trend in jellyfish abundance; (2) to investigate whether year-to-year changes in catch-biomass are due to changes in the numbers or in the size of medusa (assessed as the mean mass per individual), and (3) to determine whether inter-annual variation patterns are consistent between species and water masses. Scyphomedusae were present in 97% of samples (N = 306). Their overall annual median catch-biomass ranged from 0.19 to 0.92 g m-3 (or 8.6 to 42.4 g m-2). Aurelia aurita and Cyanea spp. (Cyanea lamarckii and Cyanea capillata) made up 77.7% and 21.5% of the total catch-biomass respectively, but species contributions varied greatly between sub-regions and years. No consistent pattern was detected between the distribution and inter-annual variations of the two genera, and contrasting inter-annual patterns emerged when considering abundance either as biomass or as density. Significantly, A. aurita medusae were heavier in stratified than in mixed waters, which we hypothesize may be linked to differences in timing and yield of primary and secondary productions between water masses. These results show the vulnerability of time-series from bycatch datasets to phenological changes and highlight the importance of taking species- and population-specific distribution patterns into account when integrating jellyfish into ecosystem models.

  14. Timing and Scope of Genomic Expansion within Annelida: Evidence from Homeoboxes in the Genome of the Earthworm Eisenia fetida. (United States)

    Zwarycz, Allison S; Nossa, Carlos W; Putnam, Nicholas H; Ryan, Joseph F


    Annelida represents a large and morphologically diverse group of bilaterian organisms. The recently published polychaete and leech genome sequences revealed an equally dynamic range of diversity at the genomic level. The availability of more annelid genomes will allow for the identification of evolutionary genomic events that helped shape the annelid lineage and better understand the diversity within the group. We sequenced and assembled the genome of the common earthworm, Eisenia fetida. As a first pass at understanding the diversity within the group, we classified 363 earthworm homeoboxes and compared them with those of the leech Helobdella robusta and the polychaete Capitella teleta. We inferred many gene expansions occurring in the lineage connecting the most recent common ancestor (MRCA) of Capitella and Eisenia to the Eisenia/Helobdella MRCA. Likewise, the lineage leading from the Eisenia/Helobdella MRCA to the leech H. robusta has experienced substantial gains and losses. However, the lineage leading from Eisenia/Helobdella MRCA to E. fetida is characterized by extraordinary levels of homeobox gain. The evolutionary dynamics observed in the homeoboxes of these lineages are very likely to be generalizable to all genes. These genome expansions and losses have likely contributed to the remarkable biology exhibited in this group. These results provide a new perspective from which to understand the diversity within these lineages, show the utility of sub-draft genome assemblies for understanding genomic evolution, and provide a critical resource from which the biology of these animals can be studied. PMID:26659921

  15. Mitochondrial genome sequence and gene order of Sipunculus nudus give additional support for an inclusion of Sipuncula into Annelida

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    Bartolomaeus Thomas


    Full Text Available Abstract Background Mitochondrial genomes are a valuable source of data for analysing phylogenetic relationships. Besides sequence information, mitochondrial gene order may add phylogenetically useful information, too. Sipuncula are unsegmented marine worms, traditionally placed in their own phylum. Recent molecular and morphological findings suggest a close affinity to the segmented Annelida. Results The first complete mitochondrial genome of a member of Sipuncula, Sipunculus nudus, is presented. All 37 genes characteristic for metazoan mtDNA were detected and are encoded on the same strand. The mitochondrial gene order (protein-coding and ribosomal RNA genes resembles that of annelids, but shows several derivations so far found only in Sipuncula. Sequence based phylogenetic analysis of mitochondrial protein-coding genes results in significant bootstrap support for Annelida sensu lato, combining Annelida together with Sipuncula, Echiura, Pogonophora and Myzostomida. Conclusion The mitochondrial sequence data support a close relationship of Annelida and Sipuncula. Also the most parsimonious explanation of changes in gene order favours a derivation from the annelid gene order. These results complement findings from recent phylogenetic analyses of nuclear encoded genes as well as a report of a segmental neural patterning in Sipuncula.

  16. Co-evolution of marine worms and their chemoautotrophic bacterial symbionts: unexpected host switches explained by ecological fitting? (United States)

    Brune, A


    Mutualistic associations of bacteria and invertebrates are widespread and encompass an enormous diversity on the side of both partners. The advantages gained from the symbiosis favour reciprocal adaptations that increase the stability of the association and can lead to codiversification of symbiont and host. While numerous examples of a strictly vertical transfer of the symbionts from parent to offspring among intracellular associations abound, little is known about the fidelity of the partners in extracellular associations, where symbionts colonize the surface or body cavity of their host. In this issue of Molecular Ecology, Zimmermann et al. () investigated the evolutionary history of the symbiotic association between a monophyletic clade of sulphur-oxidizing Gammaproteobacteria and two distantly related lineages of marine worms (nematodes and annelids). The study supports the surprising conclusion that partner fidelity does not necessarily increase with the intimacy of the association. Ectosymbionts on the cuticle of the nematodes seem to be cospeciating with their hosts, whereas endosymbionts housed in the body cavity of the annelids must have originated multiple times, probably by host switching, from ectosymbionts of sympatric nematodes. This excellent case study on the evolutionary history of invertebrate-microbe interactions supports the emerging concept that the co-evolutionary processes shaping such mutualistic symbioses include both codiversification and ecological fitting. PMID:27373707

  17. Expression of segment polarity genes in brachiopods supports a non-segmental ancestral role of engrailed for bilaterians. (United States)

    Vellutini, Bruno C; Hejnol, Andreas


    The diverse and complex developmental mechanisms of segmentation have been more thoroughly studied in arthropods, vertebrates and annelids-distantly related animals considered to be segmented. Far less is known about the role of "segmentation genes" in organisms that lack a segmented body. Here we investigate the expression of the arthropod segment polarity genes engrailed, wnt1 and hedgehog in the development of brachiopods-marine invertebrates without a subdivided trunk but closely related to the segmented annelids. We found that a stripe of engrailed expression demarcates the ectodermal boundary that delimits the anterior region of Terebratalia transversa and Novocrania anomala embryos. In T. transversa, this engrailed domain is abutted by a stripe of wnt1 expression in a pattern similar to the parasegment boundaries of insects-except for the expression of hedgehog, which is restricted to endodermal tissues of the brachiopod embryos. We found that pax6 and pax2/5/8, putative regulators of engrailed, also demarcate the anterior boundary in the two species, indicating these genes might be involved in the anterior patterning of brachiopod larvae. In a comparative phylogenetic context, these findings suggest that bilaterians might share an ancestral, non-segmental domain of engrailed expression during early embryogenesis. PMID:27561213

  18. Neuronal development in larval chiton Ischnochiton hakodadensis (Mollusca: Polyplacophora). (United States)

    Voronezhskaya, Elena E; Tyurin, Sergei A; Nezlin, Leonid P


    Chitons are the most primitive molluscs and, thus, a matter of considerable interest for understanding both basic principles of molluscan neurogenesis and phylogeny. The development of the nervous system in trochophores of the chiton Ischnochiton hakodadensis from hatching to metamorphosis is described in detail by using confocal laser scanning microscopy and antibodies raised against serotonin, FMRFamide, and acetylated alpha tubulin. The earliest nervous elements detected were peripheral neurons located in the frontal hemisphere of posthatching trochophores and projecting into the apical organ. Among them, two pairs of unique large lateral cells appear to pioneer the pathways of developing adult nervous system. Chitons possess an apical organ that contains the largest number of neurons among all molluscan larvae investigated so far. Besides, many pretrochal neurons are situated outside the apical organ. The prototroch is not innervated by larval neurons. The first neurons of the developing adult central nervous system (CNS) appear later in the cerebral ganglion and pedal cords. None of the neurons of the larval nervous system are retained in the adult CNS. They cease to express their transmitter content and disintegrate after settlement. Although the adult CNS of chitons resembles that of polychaetes, their general scenario of neuronal development resembles that of advanced molluscs and differs from annelids. Thus, our data demonstrate the conservative pattern of molluscan neurogenesis and suggest independent origin of molluscan and annelid trochophores. PMID:11835180

  19. Dietary partitioning by five sympatric species of stingray (Dasyatidae) on coral reefs. (United States)

    O'Shea, O R; Thums, M; van Keulen, M; Kempster, R M; Meekan, M G


    Dietary characteristics and the degree of dietary partitioning by five species of sympatric stingray were assessed using stomach content and sediment analyses within a coral reef lagoon at Ningaloo Reef, Western Australia (the cowtail Pastinachus atrus, blue-spotted fantail Taeniura lymma, blue-spotted mask Neotrygon kuhlii, porcupine Urogymnus asperrimus rays and the reticulate whipray Himantura uarnak). A total of 2804 items were recovered from the stomachs of 170 rays and 3215 individual taxa from the environment, which were used in selectivity analyses. Twenty-four prey taxa were identified from stomach contents and pooled into 10 taxonomic categories for analysis, of which annelids, prawns, brachyurans and bivalves were the most abundant, together accounting for 96% of the diet. Himantura uarnak had the greatest interspecific dissimilarity in diet, consuming a larger proportion of crustaceans, notably penaeids (41% of total diet) than the other four species of rays, all of which had diets dominated by annelids (71-82% of total diet). Crustacean specialization by H. uarnak may exist to maximize resources and reduce competition among sympatric species. The remaining species may partition resources on the basis of space, rather than diet. PMID:23731138

  20. Oxygen Requirements for the Cambrian Explosion

    Institute of Scientific and Technical Information of China (English)

    Xingliang Zhang; Linhao Cui


    Hypoxic tolerance experiments may be helpful to constrain the oxygen requirement for animal evolution. Based on literature review, available data demonstrate that fishes are more sensitive to hypoxia than crustaceans and echinoderms, which in turn are more sensitive than annelids, whilst mollusks are the least sensitive. Mortalities occur where O2 concentrations are below 2.0 mg/L, equivalent to saturation with oxygen content about 25% PAL (present atmospheric level). Therefore, the minimal oxygen requirement for maintaining animal diversity since Cambrian is determined as 25% PAL. The traditional view is that a rise in atmospheric oxygen concentrations led to the oxygenation of the ocean, thus triggering the evolution of animals. Geological and geochemical studies suggest a constant increase of the oxygen level and a contraction of anoxic oceans during Ediacaran–Cambrian transition when the world oceans experienced a rapid diversification of metazoan lineages. However, fossil first appearances of animal phyla are obviously asynchronous and episodic, showing a sequence as:basal metazoans>lophotrochozoans>ecdysozoans and deuterostomes. According to hitherto known data of fossil record and hypoxic sensitivity of animals, the appearance sequence of different animals is broadly consistent with their hypoxic sensitivity:animals like molluscs and annelids that are less sensitive to hypoxia appeared earlier, while animals like echinoderms and fishes that are more sensitive to hypoxia came later. Therefore, it is very likely that the appearance order of animals is corresponding to the increasing oxygen level and/or the contraction of anoxic oceans during Ediacaran–Cambrian transition.

  1. Molecular cloning and expression of TLR in the Eisenia andrei earthworm. (United States)

    Škanta, František; Roubalová, Radka; Dvořák, Jiří; Procházková, Petra; Bilej, Martin


    Toll-like receptors (TLRs) play an important role in defense responses to pathogens in invertebrates. Here we characterize the first TLR isolated from an oligochaete annelid, namely, Eisenia andrei (EaTLR) and show its expression pattern. The full-length EaTLR cDNA consists of 2615 bp encoding a putative protein of 675 amino acids. The predicted amino acid sequence comprises of an extracellular domain containing 31 amino acid signal peptide and seven leucine-rich repeats (LRR), capped with cysteine-rich N- and C-terminal LRRs followed by a transmembrane domain and cytoplasmic Toll/IL-1R domain (TIR). TIR domains of twenty individual earthworms were sequenced and the variability suggesting the presence of a high number of TLR genes in the genome of E. andrei was observed. Phylogenetic analysis revealed the highest similarity of EaTLR with polychaete annelid, Capitella teleta and TLRs of mollusks and echinoderms. Finally, the highest constitutive expression of EaTLR was observed in the digestive tract. Gene expression was significantly increased in coelomocytes of E. andrei after the challenge with Gram-positive bacteria. PMID:23969138

  2. Evolution of the notochord. (United States)

    Annona, Giovanni; Holland, Nicholas D; D'Aniello, Salvatore


    A notochord is characteristic of developing chordates (which comprise amphioxus, tunicates and vertebrates), and, more arguably, is also found in some other animals. Although notochords have been well reviewed from a developmental genetic point of view, there has heretofore been no adequate survey of the dozen or so scenarios accounting for their evolutionary origin. Advances in molecular phylogenetics and developmental genetics have, on the one hand, failed to support many of these ideas (although, it is not impossible that some of these rejects may yet, at least in part, return to favor). On the other hand, current molecular approaches have actually stimulated the revival of two of the old proposals: first that the notochord is a novelty that arose in the chordates, and second that it is derived from a homologous structure, the axochord, that was present in annelid-like ancestors. In the long term, choosing whether the notochord is a chordate novelty or a legacy from an ancient annelid (or perhaps an evolutionary derivative from precursors yet to be proposed) will probably require descriptions of gene regulatory networks involved in the development of notochords and notochord-like structures in a wide spectrum of animals. For now, one-way forward will be studies of all aspects of the biology of enteropneust hemichordates, a group widely thought to be the key to understanding the evolutionary origin of the chordates. PMID:26446368

  3. Expression pattern of Piwi-like genes in adult Myzostoma cirriferum (Annelida). (United States)

    Weigert, Anne; Helm, Conrad; Hausen, Harald; Zakrzewski, Anne-C; Bleidorn, Christoph


    Piwi-like genes are a subgroup of Argonaute genes which participate as gene regulators by gene silencing. In most bilaterians, such as mouse, human, insects, and zebrafish, their expression is mostly limited to gonadal stem cells. But there are some striking exceptions to this pattern; flatworms and acoels also express Piwi-like genes in somatic stem cells, due to their unique replacement system. Annelid species like Capitella teleta and Platynereis dumerilii express these genes in cells of the posterior growth zone as well as in gonadal stem cells. To investigate the expression pattern of Piwi-like genes in another annelid, we established in situ hybridization for adult Myzostoma cirriferum. Piwi-like gene transcripts recovered in an mRNA-seq library of pooled adult stages of M. cirriferum were expanded using RACE PCR, cloned and sequenced. ML analysis confirmed the identity of both transcripts as part of the Piwi1-like or Piwi2-like subfamily of Argonaute proteins. The results of in situ hybridization studies show that the expression of both Piwi-like genes, Mc-Piwi1 and Mc-Piwi2, is clearly located only in gonadal stem cells, and as such we did not find any evidence for the existence of a posterior growth zone nor expression in somatic stem cells. PMID:23609434

  4. Primary structure of the common polypeptide chain b from the multi-hemoglobin system of the hydrothermal vent tube worm Riftia pachyptila: an insight on the sulfide binding-site. (United States)

    Zal, F; Suzuki, T; Kawasaki, Y; Childress, J J; Lallier, F H; Toulmond, A


    The deep-sea tube worm Riftia pachyptila Jones possesses a multi-hemoglobin system with three different extracellular Hbs: two dissolved in the vascular blood, V1 (ca. 3,500 kDa) and V2 (ca. 400 kDa), and one in the coelomic fluid, C1 (ca. 400 kDa). V1 Hb consists of four heme-containing, globin chains (b-e) and four linker chains (L1-L4). V2 and C1 Hbs are exclusively built from globin chains, six for V2 (a-f) and five for C1 (a-e). The complete amino acid sequence of the isolated monomeric globin chain b, common to all Riftia Hbs, has been determined by automated Edman degradation sequencing of the peptides derived by digestion with trypsin, chymotrypsin, thermolysin, and CNBr. This polypeptide chain is composed of 144 amino acid residues, providing a M(r) of 16, 135.0 Da. Moreover, the primary sequence of chain b revealed 3 Cys residues at position 4, 75, and 134. Cys-4 and Cys-134 are located at positions where an intra-chain disulfide bridge is formed in all annelid, vestimentiferan, or pogonophoran chains, but Cys-75 is located at a unique position only found in three globin chains belonging to Lamellibrachia and Oligobrachia, a vestimentiferan and a pogonophoran. In both groups, Hbs can bind sulfide reversibly to fuel the chemosynthetic process of the symbiotic bacteria they harbor. Sulfide-binding experiments performed on purified Hb fractions (i.e., V1, V2, and C1 Hbs) suggest that free Cys residues on globin chains, and the numerous Cys found in linker chains, as determined previously by ESI-MS, may be the sulfide binding-sites. Blocking the free Cys by N-ethylmaleimide, we confirmed that free cysteines were involved in sulfide-binding but did not account for the whole sulfide-binding capacity of V1 Hb. Furthermore, a phylogenetic tree was constructed from 18 globin-like chains of annelid, vestimentiferan, and pogonophoran extracellular Hbs to clarify the systematic position of tubeworms. Riftia chain b clearly belongs to the "strain A" family with 30 to

  5. Evolution of the sulfide-binding function within the globin multigenic family of the deep-sea hydrothermal vent tubeworm Riftia pachyptila. (United States)

    Bailly, Xavier; Jollivet, Didier; Vanin, Stephano; Deutsch, Jean; Zal, Franck; Lallier, François; Toulmond, André


    The giant extracellular hexagonal bilayer hemoglobin (HBL-Hb) of the deep-sea hydrothermal vent tube worm Riftia pachyptila is able to transport simultaneously O(2) and H(2)S in the blood from the gills to a specific organ: the trophosome that harbors sulfide-oxidizing endosymbionts. This vascular HBL-Hb is made of 144 globins from which four globin types (A1, A2, B1, and B2) coevolve. The H(2)S is bound at a specific location (not on the heme site) onto two of these globin types. In order to understand how such a function emerged and evolved in vestimentiferans and other related annelids, six partial cDNAs corresponding to the six globins known to compose the multigenic family of R. pachyptila have been identified and sequenced. These partial sequences (ca. 120 amino acids, i.e., 80% of the entire protein) were used to reconstruct molecular phylogenies in order to trace duplication events that have led to the family organization of these globins and to locate the position of the free cysteine residues known to bind H(2)S. From these sequences, only two free cysteine residues have been found to occur, at positions Cys + 1 (i.e., 1 a.a. from the well-conserved distal histidine) and Cys + 11 (i.e., 11 a.a. from the same histidine) in globins B2 and A2, respectively. These two positions are well conserved in annelids, vestimentiferans, and pogonophorans, which live in sulfidic environments. The structural comparison of the hydrophobic environment that surrounds these cysteine residues (the sulfide-binding domain) using hydrophobic cluster analysis plots, together with the cysteine positions in paralogous strains, suggests that the sulfide-binding function might have emerged before the annelid radiation in order to detoxify this toxic compound. Moreover, globin evolutionary rates are highly different between paralogous strains. This suggests that either the two globin subfamilies involved in the sulfide-binding function (A2 and B2) have evolved under strong directional

  6. Phylogeny of Eunicida (Annelida) and exploring data congruence using a partition addition bootstrap alteration (PABA) approach. (United States)

    Struck, Torsten H; Purschke, Günter; Halanych, Kenneth M


    Even though relationships within Annelida are poorly understood, Eunicida is one of only a few major annelid lineages well supported by morphology. The seven recognized eunicid families possess sclerotized jaws that include mandibles and a maxillary apparatus. The maxillary apparatuses vary in shape and number of elements, and three main types are recognized in extant taxa: ctenognath, labidognath, and prionognath. Ctenognath jaws are usually considered to represent the plesiomorphic state of Eunicida, whereas taxa with labidognath and prionognath are thought to form a derived monophyletic assemblage. However, this hypothesis has never been tested in a statistical framework even though it holds considerable importance for understanding annelid phylogeny and possibly lophotrochozoan evolution because Eunicida has the best annelid fossil record. Therefore, we used maximum likelihood and Bayesian inference approaches to reconstruct Eunicida phylogeny using sequence data from nuclear 18S and 28S rDNA genes and mitochondrial 16S rDNA and cytochrome c oxidase subunit I genes. Additionally, we conducted three different tests to investigate suitability of combining data sets. Incongruence length difference (ILD) and Shimodaira-Hasegawa (SH) test comparisons of resultant trees under different data partitions have been widely used previously but do not give a good indication as to which nodes may be causing the conflict. Thus, we developed a partition addition bootstrap alteration (PABA) approach that evaluates congruence or conflict for any given node by determining how bootstrap scores are altered when different data partitions are added. PABA shows the contribution of each partition to the phylogeny obtained in the combined analysis. Generally, the ILD test performed worse than the other approaches in detecting incongruence. Both PABA and the SH approach indicated the 28S and COI data sets add conflicting signal, but PABA is more informative for elucidating which data

  7. The normal development of Platynereis dumerilii (Nereididae, Annelida

    Directory of Open Access Journals (Sweden)

    Henrich Thorsten


    Full Text Available Abstract Background The polychaete annelid Platynereis dumerilii is an emerging model organism for the study of molecular developmental processes, evolution, neurobiology and marine biology. Annelids belong to the Lophotrochozoa, the so far understudied third major branch of bilaterian animals besides deuterostomes and ecdysozoans. P. dumerilii has proven highly relevant to explore ancient bilaterian conditions via comparison to the deuterostomes, because it has accumulated less evolutionary change than conventional ecdysozoan models. Previous staging was mainly referring to hours post fertilization but did not allow matching stages between studies performed at (even slightly different temperatures. To overcome this, and to provide a first comprehensive description of P. dumerilii normal development, a temperature-independent staging system is needed. Results Platynereis dumerilii normal development is subdivided into 16 stages, starting with the zygote and ending with the death of the mature worms after delivering their gametes. The stages described can be easily identified by conventional light microscopy or even by dissecting scope. Developmental landmarks such as the beginning of phototaxis, the visibility of the stomodeal opening and of the chaetae, the first occurrence of the ciliary bands, the formation of the parapodia, the extension of antennae and cirri, the onset of feeding and other characteristics are used to define different developmental stages. The morphology of all larval stages as well as of juveniles and adults is documented by light microscopy. We also provide an overview of important steps in the development of the nervous system and of the musculature, using fluorescent labeling techniques and confocal laser-scanning microscopy. Timing of each developmental stage refers to hours post fertilization at 18 ± 0.1°C. For comparison, we determined the pace of development of larvae raised at 14°C, 16°C, 20°C, 25°C, 28°C and

  8. The preliminary data on the Aeronian (Silurian) machaerids from Lithuania (Baltic Basin) (United States)

    Radzevičius, S.; Ekleris, A.


    Machaerids are stem-Lophotrochozoans, closely related to the Annelids, and known from the Early Ordovician to Middle Permian. Machaerids is a group of worm-like benthic marine, bilaterally symmetrical, armoured invertebrate. Their body is covered by an external scleritome. The scleritome is imbricated of longitudinally arranged series of plates or sclerites. Completely articulated specimens of machaeridians are very rare, yet the systematic position of machaerids is controversial. Machaeridians had been assigned to different groups, such as barnacles, mollusks, echinoderms and annelids. The latter is prevailing, however their exact place within the annelids still remains unresolved. New findings of disarticulated Silurian machaerids have been recorded in western Lithuania, Geniai-1 core. This well has been drilled with exploration purposes regarding the Cambrian oil reservoir; therefore the biggest part of the Silurian core has not been collected. The exceptions are some parts of the Llandovery and Ludlow, which have partially recovered well core, but the identification of the precise stratigraphical position is complicated. Disarticulated sclerites of machaeridians have been found at the 1756.4 m depth, in the argillite, together with some graptolites and brachiopods. Several rhabdosome fragments of Normalograptus scalaris (Hisinger) were found together with the machaenid sclerites as well. N. scalaris has wide biostratigraphical distribution from the Rhudanian to the lower part of Telychian, which comprises the convolutus - triangulates graptolite biozones, corresponding to the 1756.8 - 1756 m depth. Convolutus - triangulates biozones represent Aeronian, and the machaeridian sclerites come from this interval, together with the Jonsea grayi (Davidson) brachiopod shells, which are very common and correspond to the BA 5-6 benthic assemblage, as well as do the graptolites found together. In previous studies, two orders of machaerids have been recognized: the

  9. Expression of the Lhx genes apterous and lim1 in an errant polychaete: implications for bilaterian appendage evolution, neural development, and muscle diversification

    Directory of Open Access Journals (Sweden)

    Winchell Christopher J


    Full Text Available Abstract Background Arthropod and vertebrate appendages appear to have evolved via parallel co-option of a plesiomorphic gene regulatory network. Our previous work implies that annelids evolved unrelated appendage-forming mechanisms; we therefore found no support for homology of parapodia and arthropodia at the level of the whole appendage. We expand on that study here by asking whether expression of the LIM homeobox (Lhx genes apterous and lim1 in the annelid Neanthes arenaceodentata supports homology of the dorsal branches as well as the proximodistal axes of parapodia and arthropodia. In addition, we explore whether the neural expression of apterous and lim1 in Neanthes supports the putative ancestral function of the Lhx gene family in regulating the differentiation and maintenance of neuronal subtypes. Results Both genes exhibit continuous expression in specific portions of the developing central nervous system, from hatching to at least the 13-chaetiger stage. For example, nerve cord expression occurs in segmentally iterated patterns consisting of diffuse sets of many lim1-positive cells and comparatively fewer, clustered pairs of apterous-positive cells. Additionally, continuous apterous expression is observed in presumed neurosecretory ganglia of the posterior brain, while lim1 is continuously expressed in stomatogastric ganglia of the anterior brain. apterous is also expressed in the jaw sacs, dorsal parapodial muscles, and a presumed pair of cephalic sensory organs, whereas lim1 is expressed in multiple pharyngeal ganglia, the segmental peripheral nervous system, neuropodial chaetal sac muscles, and parapodial ligules. Conclusions The early and persistent nervous system expression of apterous and lim1 in Neanthes juveniles supports conservation of Lhx function in bilaterian neural differentiation and maintenance. Our results also suggest that diversification of parapodial muscle precursors involves a complementary LIM code similar to

  10. Insights into metazoan evolution from alvinella pompejana cDNAs

    Directory of Open Access Journals (Sweden)

    Thierry Jean-Claude


    Full Text Available Abstract Background Alvinella pompejana is a representative of Annelids, a key phylum for evo-devo studies that is still poorly studied at the sequence level. A. pompejana inhabits deep-sea hydrothermal vents and is currently known as one of the most thermotolerant Eukaryotes in marine environments, withstanding the largest known chemical and thermal ranges (from 5 to 105°C. This tube-dwelling worm forms dense colonies on the surface of hydrothermal chimneys and can withstand long periods of hypo/anoxia and long phases of exposure to hydrogen sulphides. A. pompejana specifically inhabits chimney walls of hydrothermal vents on the East Pacific Rise. To survive, Alvinella has developed numerous adaptations at the physiological and molecular levels, such as an increase in the thermostability of proteins and protein complexes. It represents an outstanding model organism for studying adaptation to harsh physicochemical conditions and for isolating stable macromolecules resistant to high temperatures. Results We have constructed four full length enriched cDNA libraries to investigate the biology and evolution of this intriguing animal. Analysis of more than 75,000 high quality reads led to the identification of 15,858 transcripts and 9,221 putative protein sequences. Our annotation reveals a good coverage of most animal pathways and networks with a prevalence of transcripts involved in oxidative stress resistance, detoxification, anti-bacterial defence, and heat shock protection. Alvinella proteins seem to show a slow evolutionary rate and a higher similarity with proteins from Vertebrates compared to proteins from Arthropods or Nematodes. Their composition shows enrichment in positively charged amino acids that might contribute to their thermostability. The gene content of Alvinella reveals that an important pool of genes previously considered to be specific to Deuterostomes were in fact already present in the last common ancestor of the Bilaterian

  11. A replicated climate change field experiment reveals rapid evolutionary response in an ecologically important soil invertebrate. (United States)

    Bataillon, Thomas; Galtier, Nicolas; Bernard, Aurelien; Cryer, Nicolai; Faivre, Nicolas; Santoni, Sylvain; Severac, Dany; Mikkelsen, Teis N; Larsen, Klaus S; Beier, Claus; Sørensen, Jesper G; Holmstrup, Martin; Ehlers, Bodil K


    Whether species can respond evolutionarily to current climate change is crucial for the persistence of many species. Yet, very few studies have examined genetic responses to climate change in manipulated experiments carried out in natural field conditions. We examined the evolutionary response to climate change in a common annelid worm using a controlled replicated experiment where climatic conditions were manipulated in a natural setting. Analyzing the transcribed genome of 15 local populations, we found that about 12% of the genetic polymorphisms exhibit differences in allele frequencies associated to changes in soil temperature and soil moisture. This shows an evolutionary response to realistic climate change happening over short-time scale, and calls for incorporating evolution into models predicting future response of species to climate change. It also shows that designed climate change experiments coupled with genome sequencing offer great potential to test for the occurrence (or lack) of an evolutionary response. PMID:27109012

  12. Sipunculans and segmentation

    DEFF Research Database (Denmark)

    Wanninger, Andreas; Kristof, Alen; Brinkmann, Nora


    Comparative molecular, developmental and morphogenetic analyses show that the three major segmented animal groups- Lophotrochozoa, Ecdysozoa and Vertebrata-use a wide range of ontogenetic pathways to establish metameric body organization. Even in the life history of a single specimen, different...... mechanisms may act on the level of gene expression, cell proliferation, tissue differentiation and organ system formation in individual segments. Accordingly, in some polychaete annelids the first three pairs of segmental peripheral neurons arise synchronously, while the metameric commissures of the ventral...... nervous system form in anterior-posterior progression. Contrary to traditional belief, loss of segmentation may have occurred more often than commonly assumed, as exemplified in the sipunculans, which show remnants of segmentation in larval stages but are unsegmented as adults. The developmental...

  13. Metagenomic Analysis of Microbial Symbionts in a Gutless Worm

    Energy Technology Data Exchange (ETDEWEB)

    Woyke, Tanja; Teeling, Hanno; Ivanova, Natalia N.; Hunteman, Marcel; Richter, Michael; Gloeckner, Frank Oliver; Boeffelli, Dario; Barry, Kerrie W.; Shapiro, Harris J.; Anderson, Iain J.; Szeto, Ernest; Kyrpides, Nikos C.; Mussmann, Marc; Amann, Rudolf; Bergin, Claudia; Ruehland, Caroline; Rubin, Edward M.; Dubilier, Nicole


    Symbioses between bacteria and eukaryotes are ubiquitous, yet our understanding of the interactions driving these associations is hampered by our inability to cultivate most host-associated microbes. Here we use a metagenomic approach to describe four co-occurring symbionts from the marine oligochaete Olavius algarvensis, a worm lacking a mouth, gut and nephridia. Shotgun sequencing and metabolic pathway reconstruction revealed that the symbionts are sulphur-oxidizing and sulphate-reducing bacteria, all of which are capable of carbon fixation, thus providing the host with multiple sources of nutrition. Molecular evidence for the uptake and recycling of worm waste products by the symbionts suggests how the worm could eliminate its excretory system, an adaptation unique among annelid worms. We propose a model that describes how the versatile metabolism within this symbiotic consortium provides the host with an optimal energy supply as it shuttles between the upper oxic and lower anoxic coastal sediments that it inhabits.

  14. Symbiosis insights through metagenomic analysis of a microbialconsortium

    Energy Technology Data Exchange (ETDEWEB)

    Woyke, Tanja; Teeling, Hanno; Ivanova, Natalia N.; Hunteman,Marcel; Richter, Michael; Gloeckner, Frank Oliver; Boffelli, Dario; Barry, Kerrie W.; Shapiro, Harris J.; Anderson, Iain J.; Szeto, Ernest; Kyrpides, Nikos C.; Mussmann, Marc; Amann, Rudolf; Bergin, Claudia; Ruehland, Caroline; Rubin, Edward M.; Dubilier, Nicole


    Symbioses between bacteria and eukaryotes are ubiquitous, yet our understanding of the interactions driving these associations is hampered by our inability to cultivate most host-associated microbes. Here, we used a metagenomic approach to describe four co-occurring symbionts from the marine oligochaete Olavius algarvensis, a worm lacking a mouth, gut, and nephridia. Shotgun sequencing and metabolic pathway reconstruction revealed that the symbionts are sulfur-oxidizing and sulfate-reducing bacteria, all of which are capable of carbon fixation, providing the host with multiple sources of nutrition. Molecular evidence for the uptake and recycling of worm waste products by the symbionts suggests how the worm could eliminate its excretory system, an adaptation unique among annelid worms. We propose a model which describes how the versatile metabolism within this symbiotic consortium provides the host with an optimal energy supply as it shuttles between the upper oxic and lower anoxic coastal sediments which it inhabits.

  15. A new Fridericia species (Clitellata, Enchytraeidae and the enchytraeid fauna of the Őrség National Park (Hungary

    Directory of Open Access Journals (Sweden)

    Dózsa-Farkas, K.


    Full Text Available The enchytraeid fauna of the Őrség National Park (Western Hungary, hitherto unknown, was investigated in this study. 14 enchytraeid genera including 47 species and one other annelid worm (Hrabeiella periglandulata were identified. One enchytraeid species was found to be new to science and is described in this paper as Fridericia zicsii sp. nov. The new species is distinguishable based on both morphological characters and molecular data (mitochondrial cytochrome c oxidase subunit I, nuclear histone 3 genes and nuclear ribosomal ITS region sequences from similar species. The enchytraeid fauna of Őrség NP indicated well the subalpine nature of this area. The most species-rich site was the hay meadow (32 species and interestingly, the species number in the Sphagnum bog of Szőce was unusually high (19 species.

  16. A critical analysis of the biological impacts of plasticizers on wildlife

    DEFF Research Database (Denmark)

    Oehlmann, J.; Schulte-Oehlmann, U.; Kloas, W.;


    ), molluscs, crustaceans, insects, fish and amphibians. Moreover, the paper provides novel data on the biological effects of some of these plasticizers in invertebrates, fish and amphibians. Phthalates and BPA have been shown to affect reproduction in all studied animal groups, to impair development in......This review provides a critical analysis of the biological effects of the most widely used plasticizers, including dibutyl phthalate, diethylhexyl phthalate, dimethyl phthalate, butyl benzyl phthalate and bisphenol A (BPA), on wildlife, with a focus on annelids ( both aquatic and terrestrial...... crustaceans and amphibians and to induce genetic aberrations. Molluscs, crustaceans and amphibians appear to be especially sensitive to these compounds, and biological effects are observed at environmentally relevant exposures in the low ng l(-1) to mg l(-1) range. In contrast, most effects in fish ( except...

  17. Evolution of the 2'-5'-Oligoadenylate Synthetase family in eukaryotes and bacteria

    DEFF Research Database (Denmark)

    Kjær, Karina Hansen; Poulsen, Jesper Buchhave; Reitamm, Tonu;


    The 2′-5′-oligoadenylate synthetase (OAS) belongs to a nucleotidyl transferase family that includes poly(A) polymerases and CCA-adding enzymes. In mammals and birds, the OAS functions in the interferon system but it is also present in an active form in sponges, which are devoid of the interferon...... system. In view of these observations, we have pursued the idea that OAS genes could be present in other metazoans and in unicellular organisms as well. We have identified a number of OAS1 genes in annelids, mollusks, a cnidarian, chordates, and unicellular eukaryotes and also found a family of proteins...... the OASL may have evolved from an ancestor of cartilaginous fishes, and that the OAS2 and the OAS3 genes evolved from a mammalian ancestor. OAS proteins function in the interferon system in mammals. This system is only found in jawed vertebrates. We therefore suggest that the original function of OAS...

  18. Burrowing mechanics: burrow extension by crack propagation. (United States)

    Dorgan, Kelly M; Jumars, Peter A; Johnson, Bruce; Boudreau, B P; Landis, Eric


    Until now, the analysis of burrowing mechanics has neglected the mechanical properties of impeding, muddy, cohesive sediments, which behave like elastic solids. Here we show that burrowers can progress through such sediments by using a mechanically efficient, previously unsuspected mechanism--crack propagation--in which an alternating 'anchor' system of burrowing serves as a wedge to extend the crack-shaped burrow. The force required to propagate cracks through sediment in this way is relatively small: we find that the force exerted by the annelid worm Nereis virens in making and moving into such a burrow amounts to less than one-tenth of the force it needs to use against rigid aquarium walls. PMID:15690029

  19. The combined effect of freeze thaw events and heavy metal pollution leads to distinct lethal synergy in Enchytraeus albidus

    DEFF Research Database (Denmark)

    Boas, Sara Wincentz; Slotsbo, Stine; Holmstrup, Martin

    Europe, and recent interest in increasing mineral deposit mining activity in arctic regions further emphasizes the need for focus on the environmental impact in these areas. In the present study it was investigated how the combination of freeze-thaw events and copper contamination of soil affected the....... Bioaccumulation of copper was also quantified to expose any increase in body burden in freeze-thaw treated worms. Regardless of the physiological responses, it is evident that arctic organisms are negatively affected by the environmental impact of global warming and exploitation of mineral deposits through mining....... Icelandic, freeze tolerant annelid worm, Enchytraeus albidus. Worms were exposed to one of three temperature treatments (constant +1.5⁰C, constant -6⁰C, or daily cycles between +1.5 and -6⁰C) in combination with one of several different copper (CuCl2) concentrations in soil. The results showed a distinct...

  20. Lophotrochozoan mitochondrial genomes

    Energy Technology Data Exchange (ETDEWEB)

    Valles, Yvonne; Boore, Jeffrey L.


    Progress in both molecular techniques and phylogeneticmethods has challenged many of the interpretations of traditionaltaxonomy. One example is in the recognition of the animal superphylumLophotrochozoa (annelids, mollusks, echiurans, platyhelminthes,brachiopods, and other phyla), although the relationships within thisgroup and the inclusion of some phyla remain uncertain. While much ofthis progress in phylogenetic reconstruction has been based on comparingsingle gene sequences, we are beginning to see the potential of comparinglarge-scale features of genomes, such as the relative order of genes.Even though tremendous progress is being made on the sequencedetermination of whole nuclear genomes, the dataset of choice forgenome-level characters for many animals across a broad taxonomic rangeremains mitochondrial genomes. We review here what is known aboutmitochondrial genomes of the lophotrochozoans and discuss the promisethat this dataset will enable insight into theirrelationships.

  1. Effect factors for marine eutrophication in LCIA based on species sensitivity to hypoxia

    DEFF Research Database (Denmark)

    Cosme, Nuno Miguel Dias; Hauschild, Michael Zwicky


    -observed-effect-concentrations (LOEC), were compiled from literature for 91 demersal species of fish, crustaceans, molluscs, echinoderms, annelids, and cnidarians, and converted to temperature-specific benthic (100 m depth) LOEC values. Species distribution and LOEC values were combined using a species sensitivity distribution (SSD...... climate zones (CZ) to represent the change in effect due to a variation of the stressor intensity, or EF = ΔPAF/ΔDO = 0.5/HC50LOEC. Results range from 218 (PAF) m3 kgO2 -1 (polar CZ) to 306 (PAF) m3 kgO2 -1 (tropical CZ). Variation between CZs was modest so a site-generic global EF of 264 (PAF) m3 kgO2 -1...

  2. Downstream collecting in ciliary suspension feeders: the catch-up principle

    DEFF Research Database (Denmark)

    Riisgård, Hans Ulrik; Nielsen, Claus; Larsen, Poul Scheel


    Based on observations of feeding structures and currents in the polychaete Spirorbis tridentatus, the entoproct Loxosoma pectinaricola and the cycliophore Symbion pandora, which all possess compound cilia, it is hypothesized that their capture mechanism is based on the catch-up principle. According...... to this principle, the compound cilia constitute the pump which generates a flow with suspended particles that enters the ciliary region. In this region the same cilia, during their power stroke, catch up with suspended particles and transfer the particles to a food groove, or a mouth cavity. In the...... the ciliary bands of some rotifers and of the various types of trochophora larvae of annelids, molluscs and entoprocts, it is hypothesized that the feeding mechanisms of these organisms are based on the catch-up principle....


    Institute of Scientific and Technical Information of China (English)

    Christian F. Kammerer


    New replacement names for the preoccupied mite genera Absentia Huang, 2001 and Venilia Kuznetsov, 1979 are proposed (Huangiella nom. nov. and Kuznetsovia nom. nov. , respectively. ). Fourteen further new replacement names are proposed for additional preoccupied generic names in the Arthropoda. These names are: Vailimia nom. nov. , Millidgella nom. nov., and Nolavia nom. nov. in Araneae, Vadumasonium nom. nov. in Hymenoptera, Gridellia nom. nov.,Vanstaronia nom. nov. and Veraniella nom. nov. in Coleoptera, Poletaevega nom. nov. in Trilobita, Vandelia nom. Isopoda, Gandoa nom. nov. and Vanuachela nom. nov. in Decapoda, and Crasquinia nom. nov. , Oertlia nom. nov. ,and Soleaua nom. nov. in Ostracoda. Additionally, one new annelid replacement name, Omodeodrilus nom. nov., is proposed.

  4. β-catenin-driven binary cell fate decisions in animal development. (United States)

    Bertrand, Vincent


    The Wnt/β-catenin pathway plays key roles during animal development. In several species, β-catenin is used in a reiterative manner to regulate cell fate diversification between daughter cells following division. This binary cell fate specification mechanism has been observed in animals that belong to very diverse phyla: the nematode Caenorhabditis elegans, the annelid Platynereis, and the ascidian Ciona. It may also play a role in the regulation of several stem cell lineages in vertebrates. While the molecular mechanism behind this binary cell fate switch is not fully understood, it appears that both secreted Wnt ligands and asymmetric cortical factors contribute to the generation of the difference in nuclear β-catenin levels between daughter cells. β-Catenin then cooperates with lineage specific transcription factors to induce the expression of novel sets of transcription factors at each round of divisions, thereby diversifying cell fate. For further resources related to this article, please visit the WIREs website. PMID:26952169

  5. Diet of the freshwater stingray Potamotrygon motoro (Chondrichthyes: Potamotrygonidae) on Marajó Island (Pará, Brazil). (United States)

    Almeida, M P; Lins, P M O; Charvet-Almeida, P; Barthem, R B


    The stomach contents of 137 examples of Potamotrygon motoro caught in 3 locations (Muaná, Afuá and Lake Arari) on Marajó Island were analysed. The values of the Index of Relative Importance (IRI) and its respective percentage (%IRI) were calculated. The level of repletion 1 (1/4 full) was the most representative for both sexes, as well as for immature and mature specimens. Most of the food items found were well-digested. The food items identification indicated the presence of 15 orders, including insects, mollusks, crustaceans, annelids and fish. Differences in diet were observed among the locations studied when comparing %IRI, crustaceans being the most preferred in Afuá, fish in Lake Arari and mollusks in Muaná. PMID:20231973

  6. Macrozoobenthos of the danubean lake Crivoe in the conditions of anthropogenous influence

    Directory of Open Access Journals (Sweden)

    Y. M. Dzhurtubaev


    Full Text Available In the summer of 2009 macrozoobenthos of the danubean Lake Crivoe, located in the Odessaarea was studied. 26 species of sponges, annelids, crustaceans, insects, gastropods and bivalves were revealed. In the upper and middle part of the lake 24 were found, in the lower one 9 species were detected. Oligochetes, and larvae of dragonflies and chironomids are characterised by the greatest number (up to 300 spec/m², the greatest biomass was found for gastropod molluscs (to 17 g/m². The total maximal number of the macrozoobenthos reached 880 spec/m² and biomass – 40.2 g/m². Benthic faunas of two lakes, Crivoe and Lung, were compared.

  7. Not whale-fall specialists, Osedax worms also consume fishbones. (United States)

    Rouse, Greg W; Goffredi, Shana K; Johnson, Shannon B; Vrijenhoek, Robert C


    Marine annelid worms of the genus Osedax exploit sunken vertebrate bones for food. To date, the named species occur on whale or other mammalian bones, and it is argued that Osedax is a whale-fall specialist. To assess whether extant Osedax species could obtain nutrition from non-mammalian resources, we deployed teleost bones and calcified shark cartilage at approximately 1000 m depth for five months. Although the evidence from shark cartilage was inconclusive, the teleost bones hosted three species of Osedax, each of which also lives off whalebones. This suggests that rather than being a whale-fall specialist, Osedax has exploited and continues to exploit a variety of food sources. The ability of Osedax to colonize and to grow on fishbone lends credibility to a hypothesis that it might have split from its siboglinid relatives to assume the bone-eating lifestyle during the Cretaceous, well before the origin of marine mammals. PMID:21490008

  8. An oligochaete homologue of the Brachyury gene is expressed transiently in the third quartette of micromeres. (United States)

    Kitakoshi, Tomohito; Shimizu, Takashi


    We have isolated a Brachyury homologue (Ttu-Bra) from the oligochaete annelid Tubifex tubifex which displays a direct mode of development. Developmental RT-PCR analysis showed that Ttu-Bra transcripts are present in embryos at stages 9-11, 16 and 17, but undetectable at the remaining embryonic stages. Whole-mount in situ hybridization demonstrated that Ttu-Bra is expressed transiently in the third quartette of micromeres, which are located at the prospective stomodaeum (at stages 9-11). The second burst of Ttu-Bra expression occurs at the posterior end of stage 16 embryo that undergoes body elongation. Ttu-Bra-expressing cells, which are organized in a circle at stage 16, become aggregated at the proctodaeum at stage 17. Consistent with the results of the RT-PCR analysis, there is no sign of Ttu-Bra-expressing cells in embryos that undergo gastrulation during stages 12-15. PMID:20603182

  9. Southern hemisphere deep-water stylasterid corals including a new species, Errina labrosa sp. n. (Cnidaria, Hydrozoa, Stylasteridae, with notes on some symbiotic scalpellids (Cirripedia, Thoracica, Scalpellidae

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    Daniela Pica


    Full Text Available A number of stylasterid corals are known to act as host species and create refuges for a variety of mobile and sessile organisms, which enhances their habitat complexity. These include annelids, anthozoans, cirripeds, copepods, cyanobacteria, echinoderms, gastropods, hydroids and sponges. Here we report the first evidence of a diverse association between stylasterids and scalpellid pedunculate barnacles and describe a new stylasterid species, Errina labrosa, from the Tristan da Cunha Archipelago. Overall, five stylasterid species are found to host eight scalpellid barnacles from several biogeographic regions in the southern hemisphere (Southern Ocean, temperate South America and the southern Indo-Pacific realms. There is an apparent lack of specificity in this kind of association and different grades of reaction to the symbiosis have been observed in the coral. These records suggest that the association between pedunculate barnacles and hard stylasterid corals has a wide distribution among different biogeographic realms and that it is relatively rare and confined largely to deep water.

  10. Multigene analysis of lophophorate and chaetognath phylogenetic relationships. (United States)

    Helmkampf, Martin; Bruchhaus, Iris; Hausdorf, Bernhard


    Maximum likelihood and Bayesian inference analyses of seven concatenated fragments of nuclear-encoded housekeeping genes indicate that Lophotrochozoa is monophyletic, i.e., the lophophorate groups Bryozoa, Brachiopoda and Phoronida are more closely related to molluscs and annelids than to Deuterostomia or Ecdysozoa. Lophophorates themselves, however, form a polyphyletic assemblage. The hypotheses that they are monophyletic and more closely allied to Deuterostomia than to Protostomia can be ruled out with both the approximately unbiased test and the expected likelihood weights test. The existence of Phoronozoa, a putative clade including Brachiopoda and Phoronida, has also been rejected. According to our analyses, phoronids instead share a more recent common ancestor with bryozoans than with brachiopods. Platyhelminthes is the sister group of Lophotrochozoa. Together these two constitute Spiralia. Although Chaetognatha appears as the sister group of Priapulida within Ecdysozoa in our analyses, alternative hypothesis concerning chaetognath relationships could not be rejected. PMID:17937996

  11. A study of radionuclide transfer between invertebrates and their marine sedimentary environment

    International Nuclear Information System (INIS)

    Exchanges between sediment and marine organisms were studied in some benthic marine invertebrates, especially Arenicola marina L. (an Annelid). Experiments were carried out on the transfer of 60Co, 137Cs and accessorily 59Fe and 144Ce. Water was the chief vector for benthic marine invertebrates. These invertebrates seemed to act mainly in sedimentary areas on the redistribution of adsorbed radionuclides within the sediment. Radioactive contamination of the invertebrates was affected by various physiological or ecological factors. Benthic marine invertebrates were then studied as links in food chains. The transfer of 60Co was studied in three food chains or fractions of food chains. The procedure allowed interesting observations from the health protection point of view and more fundamental investigations on cobalt metabolism (regulation, excretion) in a mollusc, a crustacea and a teleost

  12. Articulated Wiwaxia from the Cambrian Stage 3 Xiaoshiba Lagerstätte (United States)

    Yang, Jie; Smith, Martin R.; Lan, Tian; Hou, Jin-Bo; Zhang, Xi-Guang


    Wiwaxia is a bizarre metazoan that has been interpreted as a primitive mollusc and as a polychaete annelid worm. Extensive material from the Burgess Shale provides a detailed picture of its morphology and ontogeny, but the fossil record outside this lagerstätte is scarce, and complete wiwaxiids are particularly rare. Here we report small articulated specimens of Wiwaxia foliosa sp. nov. from the Xiaoshiba fauna (Cambrian Stage 3, Hongjingshao Formation, Kunming, south China). Although spines are absent, the fossils' sclerites - like those of W. corrugata - are symmetrically arranged in five distinct zones. They form rows across the body, and were individually added and shed throughout growth to retain an approximately symmetrical body shape. Their development pattern suggests a molluscan affinity. The basic body plan of wiwaxiids is fundamentally conserved across two continents through Cambrian Stages 3-5 - revealing morphological stasis in the wake of the Cambrian explosion.

  13. New species of Pisionidens (Sigalionidae, Annelida) from Akumal, México. (United States)

    Petersen, H Cecilie B; Gonzalez, Brett C; Martínez, Alejandro; Worsaae, Katrine


    Pisionidens Aiyar & Alikuhni, 1943 is a genus of small scale-less annelids formerly belonging to the family 'Pisionidae', now synonymized with the scale worm family Sigalionidae. A new species from Akumal, México, Pisionidens ixazaluohae n. sp., is herein described, including a genetic barcode, and diagnosed by parapodia from segment 8, males having a continuous line of midventral pores, and the presence of a single copulatory segment without parapodia. The new species differs in morphology from the three previously described species, including P. indica (Aiyar & Alikuhni, 1940), representing the only other species previously reported from the Caribbean Sea and Gulf of Mexico. A comparative table with a summary of the main taxonomic characters of all described species of the genus, including information on distribution, is provided. PMID:27395710

  14. Benthic community structure in the Gorgan Bay (Southeast of the Caspian Sea, Iran: Correlation to water physiochemical factors and heavy metal concentration of sediment

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    Mahmood Saghali


    Full Text Available Macrobentos frequency and biomass was investigated in the Gorgan Bay in 2011. Five sampling sites were chosen to collect benthos and sediment from the Bay using a Van Veen grab sampler. Samples were collected seasonally. Macrobenthos were indentified and their biomass was recorded. Sediment heavy metals concentration were measured using Atomic Absorption Spectroscopy. A total of 11 families belonging to three phyla of invertebrates were found. The phyla were Annelids (Nereidae, Naididae, Ampharetidae, Lumbriculidae, Tubificidae and Amphiporidae, Arthropods (Pontogammaridae, Balanidae and Chironomidae and Mollusks (Cardiidae and Scrobicularidae. Lumbriculidae (413 individuals m-2, corresponding to 18.7% and Cardiidae (55.2 g m-2, corresponding to 82.4% had the highest frequency and biomass, respectively. Annelids with an average of 1557 individuals m-2 was the most frequent groups, while, mollusks with the average of 141 g per m2 had the highest biomass. Results showed that macrobenthos frequency in summer was significantly higher than those of the other seasons, however, in the case of biomass, there was a significantly higher biomass in the spring than the other seasons. The maximum metal concentration was related to Zn and Pb, whereas, Cr and Cd had the lowest values. There was no significant difference in Zn and Cr concentrations among the sampling seasons. Pb concentration in winter was significantly lower than the other seasons, whereas, Cd concentrations in the spring and summer were significantly lower than the autumn and winter. There were some correlations between benthos frequency and water physiochemical characteristics and sediment heavy metal levels. This study indicated that benthic fauna of the Gorgan Bay and the Caspian Sea are not similar. Also, results showed that benthic fauna communities are affected by sediment heavy metal concentrations and water physiochemical characteristics, however, different benthos groups show

  15. Closely coupled evolutionary history of ecto- and endosymbionts from two distantly related animal phyla. (United States)

    Zimmermann, Judith; Wentrup, Cecilia; Sadowski, Miriam; Blazejak, Anna; Gruber-Vodicka, Harald R; Kleiner, Manuel; Ott, Jörg A; Cronholm, Bodil; De Wit, Pierre; Erséus, Christer; Dubilier, Nicole


    The level of integration between associated partners can range from ectosymbioses to extracellular and intracellular endosymbioses, and this range has been assumed to reflect a continuum from less intimate to evolutionarily highly stable associations. In this study, we examined the specificity and evolutionary history of marine symbioses in a group of closely related sulphur-oxidizing bacteria, called Candidatus Thiosymbion, that have established ecto- and endosymbioses with two distantly related animal phyla, Nematoda and Annelida. Intriguingly, in the ectosymbiotic associations of stilbonematine nematodes, we observed a high degree of congruence between symbiont and host phylogenies, based on their ribosomal RNA (rRNA) genes. In contrast, for the endosymbioses of gutless phallodriline annelids (oligochaetes), we found only a weak congruence between symbiont and host phylogenies, based on analyses of symbiont 16S rRNA genes and six host genetic markers. The much higher degree of congruence between nematodes and their ectosymbionts compared to those of annelids and their endosymbionts was confirmed by cophylogenetic analyses. These revealed 15 significant codivergence events between stilbonematine nematodes and their ectosymbionts, but only one event between gutless phallodrilines and their endosymbionts. Phylogenetic analyses of 16S rRNA gene sequences from 50 Cand. Thiosymbion species revealed seven well-supported clades that contained both stilbonematine ectosymbionts and phallodriline endosymbionts. This closely coupled evolutionary history of marine ecto- and endosymbionts suggests that switches between symbiotic lifestyles and between the two host phyla occurred multiple times during the evolution of the Cand. Thiosymbion clade, and highlights the remarkable flexibility of these symbiotic bacteria. PMID:26826340

  16. The spatial and temporal expression of Ch-en, the engrailed gene in the polychaete Chaetopterus, does not support a role in body axis segmentation (United States)

    Seaver, E. C.; Paulson, D. A.; Irvine, S. Q.; Martindale, M. Q.


    We are interested in understanding whether the annelids and arthropods shared a common segmented ancestor and have approached this question by characterizing the expression pattern of the segment polarity gene engrailed (en) in a basal annelid, the polychaete Chaetopterus. We have isolated an en gene, Ch-en, from a Chaetopterus cDNA library. Genomic Southern blotting suggests that this is the only en class gene in this animal. The predicted protein sequence of the 1.2-kb cDNA clone contains all five domains characteristic of en proteins in other taxa, including the en class homeobox. Whole-mount in situ hybridization reveals that Ch-en is expressed throughout larval life in a complex spatial and temporal pattern. The Ch-en transcript is initially detected in a small number of neurons associated with the apical organ and in the posterior portion of the prototrochophore. At later stages, Ch-en is expressed in distinct patterns in the three segmented body regions (A, B, and C) of Chaetopterus. In all segments, Ch-en is expressed in a small set of segmentally iterated cells in the CNS. In the A region, Ch-en is also expressed in a small group of mesodermal cells at the base of the chaetal sacs. In the B region, Ch-en is initially expressed broadly in the mesoderm that then resolves into one band/segment coincident with morphological segmentation. The mesodermal expression in the B region is located in the anterior region of each segment, as defined by the position of ganglia in the ventral nerve cord, and is involved in the morphogenesis of segment-specific feeding structures late in larval life. We observe banded mesodermal and ectodermal staining in an anterior-posterior sequence in the C region. We do not observe a segment polarity pattern of expression of Ch-en in the ectoderm, as is observed in arthropods. Copyright 2001 Academic Press.

  17. Animal-sediment interactions: the effect of ingestion and excretion by worms on mineralogy (United States)

    Needham, S. J.; Worden, R. H.; McIlroy, D.


    By controlled experiments that simulate marine depositional environments, it is shown that accelerated weathering and clay mineral authigenesis occur during the combined process of ingestion, digestion and excretion of fine-grained sediment by two species of annelid worms. Previously characterized synthetic mud was created using finely ground, low-grade metamorphic slate (temperature approximately 300°C) containing highly crystalline chlorite and muscovite. This was added to experiment and control tanks along with clean, wind-blown sand. Faecal casts were collected at regular intervals from the experimental tanks and, less frequently, from the control tanks. Over a period of many months the synthetic mud (slate) proved to be unchanged in the control tanks, but was significantly different in faecal casts from the experimental tanks that contained the worms Arenicola marina and Lumbricus terrestris. Chlorite was preferentially destroyed during digestion in the gut of A. marina. Both chlorite and muscovite underwent XRD peak broadening with a skew developing towards higher lattice spacing, characteristic of smectite formation. A neoformed Fe-Mg-rich clay mineral (possibly berthierine) and as-yet undefined clay minerals with very high d-spacing were detected in both A. marina and L. terrestris cast samples. We postulate that a combination of the low pH and bacteria-rich microenvironment in the guts of annelid worms may radically accelerate mineral dissolution and clay mineral precipitation processes during digestion. These results show that macrobiotic activity significantly accelerates weathering and mineral degradation as well as mineral authigenesis. The combined processes of sediment ingestion and digestion thus lead to early diagenetic growth of clay minerals in clastic sediments.

  18. Development of the excretory system in a polyplacophoran mollusc: stages in metanephridial system development

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    Baeumler Natalie


    Full Text Available Abstract Background Two types of excretory systems, protonephridia and metanephridial systems are common among bilaterians. The homology of protonephridia of lophotrochozoan taxa has been widely accepted. In contrast, the homology of metanephridial systems – including coelomic cavities as functional units – among taxa as well as the homology between the two excretory systems is a matter of ongoing discussion. This particularly concerns the molluscan kidneys, which are mostly regarded as being derived convergently to the metanephridia of e.g. annelids because of different ontogenetic origin. A reinvestigation of nephrogenesis in polyplacophorans, which carry many primitive traits within molluscs, could shed light on these questions. Results The metanephridial system of Lepidochitona corrugata develops rapidly in the early juvenile phase. It is formed from a coelomic anlage that soon achieves endothelial organization. The pericardium and heart are formed from the central portion of the anlage. The nephridial components are formed by outgrowth from lateral differentiations of the anlage. Simultaneously with formation of the heart, podocytes appear in the atrial wall of the pericardium. In addition, renopericardial ducts, kidneys and efferent nephroducts, all showing downstream ciliation towards the internal lumen, become differentiated (specimen length: 0.62 mm. Further development consists of elongation of the kidney and reinforcement of filtration and reabsorptive structures. Conclusions During development and in fully formed condition the metanephridial system of Lepidochitona corrugata shares many detailed traits (cellular and overall organization with the protonephridia of the same species. Accordingly, we suggest a serial homology of various cell types and between the two excretory systems and the organs as a whole. The formation of the metanephridial system varies significantly within Mollusca, thus the mode of formation cannot be used

  19. Hox and ParaHox gene expression in early body plan patterning of polyplacophoran mollusks. (United States)

    Fritsch, Martin; Wollesen, Tim; Wanninger, Andreas


    Molecular developmental studies of various bilaterians have shown that the identity of the anteroposterior body axis is controlled by Hox and ParaHox genes. Detailed Hox and ParaHox gene expression data are available for conchiferan mollusks, such as gastropods (snails and slugs) and cephalopods (squids and octopuses), whereas information on the putative conchiferan sister group, Aculifera, is still scarce (but see Fritsch et al., 2015 on Hox gene expression in the polyplacophoran Acanthochitona crinita). In contrast to gastropods and cephalopods, the Hox genes in polyplacophorans are expressed in an anteroposterior sequence similar to the condition in annelids and other bilaterians. Here, we present the expression patterns of the Hox genes Lox5, Lox4, and Lox2, together with the ParaHox gene caudal (Cdx) in the polyplacophoran A. crinita. To localize Hox and ParaHox gene transcription products, we also investigated the expression patterns of the genes FMRF and Elav, and the development of the nervous system. Similar to the other Hox genes, all three Acr-Lox genes are expressed in an anteroposterior sequence. Transcripts of Acr-Cdx are seemingly present in the forming hindgut at the posterior end. The expression patterns of both the central class Acr-Lox genes and the Acr-Cdx gene are strikingly similar to those in annelids and nemerteans. In Polyplacophora, the expression patterns of the Hox and ParaHox genes seem to be evolutionarily highly conserved, while in conchiferan mollusks these genes are co-opted into novel functions that might have led to evolutionary novelties, at least in gastropods and cephalopods. PMID:27098677

  20. Development of the excretory system in a polyplacophoran mollusc: stages in metanephridial system development (United States)


    Background Two types of excretory systems, protonephridia and metanephridial systems are common among bilaterians. The homology of protonephridia of lophotrochozoan taxa has been widely accepted. In contrast, the homology of metanephridial systems – including coelomic cavities as functional units – among taxa as well as the homology between the two excretory systems is a matter of ongoing discussion. This particularly concerns the molluscan kidneys, which are mostly regarded as being derived convergently to the metanephridia of e.g. annelids because of different ontogenetic origin. A reinvestigation of nephrogenesis in polyplacophorans, which carry many primitive traits within molluscs, could shed light on these questions. Results The metanephridial system of Lepidochitona corrugata develops rapidly in the early juvenile phase. It is formed from a coelomic anlage that soon achieves endothelial organization. The pericardium and heart are formed from the central portion of the anlage. The nephridial components are formed by outgrowth from lateral differentiations of the anlage. Simultaneously with formation of the heart, podocytes appear in the atrial wall of the pericardium. In addition, renopericardial ducts, kidneys and efferent nephroducts, all showing downstream ciliation towards the internal lumen, become differentiated (specimen length: 0.62 mm). Further development consists of elongation of the kidney and reinforcement of filtration and reabsorptive structures. Conclusions During development and in fully formed condition the metanephridial system of Lepidochitona corrugata shares many detailed traits (cellular and overall organization) with the protonephridia of the same species. Accordingly, we suggest a serial homology of various cell types and between the two excretory systems and the organs as a whole. The formation of the metanephridial system varies significantly within Mollusca, thus the mode of formation cannot be used as a homology criterion

  1. Preliminary studies of quality assessment of aquatic environments from Cluj suburban areas, based on some invertebrates bioindicators and chemical indicators

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    Gheorghe Stan


    Full Text Available Systematic categories of invertebrates bioindicators correlated with some chemical parameters,were an effective way to characterize the quality of lotic (Someş River and lentic (Lake Gilău aquatic environment from Cluj-Napoca area. Invertebrate fauna was represented by species belonging to the following dominant systematic categories: Nematoda, Annelida, Crustacea and Insecta. This paper containsalso some preliminary data on the bioindicators species belonging to Protozoa phylum. Dominant groups were crustaceans (the sampling points in Lake Gilău and annelids (Somes River and among species Gammarus pulex, Daphnia pulex, Tubifex tubifex. The fauna composition shows the β-α mesosaprobic character of the water, with an evolution from β mesosaprobity upstream the Cluj-Napoca city to polysaprobic downstream of the city. This aspect has been observed and analyzed according to chemical parameters (pH, TDS, ORP, EC, t and indices of saprobity (relative cleanliness, state of relative pollution, the deficit of species, saprobiological index.Systematic categories of invertebrates bioindicators correlated with some chemical parameters, were an effective way to characterize the quality of lotic (Someş River and lentic (Lake Gilău aquatic environment from Cluj-Napoca area. Invertebrate fauna was represented by species belonging to the following dominant systematic categories: Nematoda, Annelida, Crustacea and Insecta. This paper contains also some preliminary data on the bioindicators species belonging to Protozoa phylum. Dominant groups were crustaceans (the sampling points in Lake Gilău and annelids (Somes River and among species Gammarus pulex, Daphnia pulex, Tubifex tubifex. The fauna composition shows the β-α mesosaprobic character of the water, with an evolution from β mesosaprobity upstream the Cluj-Napoca city to polysaprobic downstream of the city. This aspect has been observed and analyzed according to chemical parameters (pH, TDS, ORP

  2. The biogeochemistry of carbon in continental slope sediments: The North Carolina margin

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    Blair, N.; Levin, L.; DeMaster, D.; Plaia, G.; Martin, C.; Fornes, W.; Thomas, C.; Pope, R.


    The responses of the continental slope benthos to organic detritus deposition were studied with a multiple trace approach. Study sites were offshore of Cape Fear (I) and Cape Hatteras (III), N.C. (both 850 m water depth) and were characterized by different organic C deposition rates, macrofaunal densities (III>I in both cases) and taxa. Natural abundances of {sup 13}C and {sup 12}C in particulate organic carbon (POC), dissolved inorganic carbon (DIC) and macrofauna indicate that the reactive organic detritus is marine in origin. Natural abundance levels of {sup 14}C and uptake of {sup 13}C-labeled diatoms by benthic animals indicate that they incorporate a relatively young component of carbon into their biomass. {sup 13}C-labeled diatoms (Thalassiorsira pseudonana) tagged with {sup 210}Pb, slope sediment tagged with {sup 113}Sn and {sup 228}Th-labeled glass beads were emplaced in plots on the seafloor at both locations and the plots were sampled after 30 min., 1-1.5 d and 14 mo. At Site I, tracer diatom was intercepted at the surface primarily by protozoans and surface-feeding annelids. Little of the diatom C penetrated below 2 cm even after 14 months. Oxidation of organic carbon appeared to be largely aerobic. At Site III, annelids were primarily responsible for the initial uptake of tracer. On the time scale of days, diatom C was transported to a depth of 12 cm and was found in animals collected between 5-10 cm. The hoeing of tracer from the surface by the maldanid Praxillela sp. may have been responsible for some of the rapid nonlocal transport. Oxidation of the diatom organic carbon was evident to at least 10 cm depth. Anaerobic breakdown of organic matter is more important at Site III. Horizontal transport, which was probably biologically mediated, was an order of magnitude more rapid than vertical displacement over a year time scale. If the horizontal transport was associated with biochemical transformations of the organic matter, it may represent an

  3. Macrofauna of shallow hydrothermal vents on the Arctic Mid-Ocean Ridge at 71N (United States)

    Schander, C.; Rapp, H. T.; Pedersen, R. B.


    Deep-sea hydrothermal vents are usually associated with a highly specialized fauna and since their discovery in 1977, more than 400 species of animals have been described. Specialized vent fauna includes various animal phyla, but the most conspicuous and well known are annelids, mollusks and crustaceans. We have investigated the fauna collected around newly discovered hydrothermal vents on the Mohns Ridge north of Jan Mayen. The venting fields are located at 71°N and the venting takes place within two main areas separated by 5 km. The shallowest vent area is at 500-550 m water depth and is located at the base of a normal fault. This vent field stretches approximately 1 km along the strike of the fault, and it is composed of 10-20 major vent sites each with multiple chimney constructions discharging up to 260°C hot fluids. A large area of diffuse, low- temperature venting occurs in the area surrounding the high-temperature field. Here, partly microbial mediated iron-oxide-hydroxide deposits are abundant. The hydrothermal vent sites do not show any high abundance of specialized hydrothermal vent fauna. Single groups (i.e. Porifera and Mollusca) have a few representatives but groups otherwise common in hydrothermal vent areas (e.g. vestimentifera, Alvinellid worms, mussels, clams, galathaeid and brachyuran crabs) are absent. Up until now slightly more than 200 species have been identified from the vent area. The macrofauna found in the vent area is, with few exceptions, an assortment of bathyal species known in the area. One endemic, yet undescribed, species of mollusc has been found so far, an gastropod related to Alvania incognita Warén, 1996 and A. angularis Warén, 1996 (Rissoidae), two species originally described from pieces of sunken wood north and south of Iceland. It is by far the most numerous mollusc species at the vents and was found on smokers, in the bacterial mats, and on the ferric deposits. A single specimen of an undescribed tanaidacean has also

  4. Cleavage pattern and fate map of the mesentoblast, 4d, in the gastropod Crepidula: a hallmark of spiralian development

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    Lyons Deirdre C


    Full Text Available Abstract Background Animals with a spiral cleavage program, such as mollusks and annelids, make up the majority of the superphylum Lophotrochozoa. The great diversity of larval and adult body plans in this group emerges from this highly conserved developmental program. The 4d micromere is one of the most conserved aspects of spiralian development. Unlike the preceding pattern of spiral divisions, cleavages within the 4d teloblastic sublineages are bilateral, representing a critical transition towards constructing the bilaterian body plan. These cells give rise to the visceral mesoderm in virtually all spiralians examined and in many species they also contribute to the endodermal intestine. Hence, the 4d lineage is an ideal one for studying the evolution and diversification of the bipotential endomesodermal germ layer in protostomes at the level of individual cells. Little is known of how division patterns are controlled or how mesodermal and endodermal sublineages diverge in spiralians. Detailed modern fate maps for 4d exist in only a few species of clitellate annelids, specifically in glossiphoniid leeches and the sludge worm Tubifex. We investigated the 4d lineage in the gastropod Crepidula fornicata, an established model system for spiralian biology, and in a closely related direct-developing species, C. convexa. Results High-resolution cell lineage tracing techniques were used to study the 4d lineage of C. fornicata and C. convexa. We present a new nomenclature to name the progeny of 4d, and report the fate map for the sublineages up through the birth of the first five pairs of teloblast daughter cells (when 28 cells are present in the 4d sublineage, and describe each clone’s behavior during gastrulation and later stages as these undergo differentiation. We identify the precise origin of the intestine, two cells of the larval kidney complex, the larval retractor muscles and the presumptive germ cells, among others. Other tissues that arise

  5. Análisis filogenético de Paepalanthus (Eriocaulaceae Andinos seleccionados con énfasis en las especies presentes en Colombia

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    González Favio


    Full Text Available El género Paepalanthus Kunth, el más grande de la familia Eriocaulaceae, comprende aproximadamente 485 especies
    distribuidas en el neotrópico con unos pocos representantes en las regiones tropicales de África. En América, se encuentra desde México hasta Bolivia y Brasil, con una distribución altitudinal disyunta entre tierras bajas como los llanos de Colombia y Venezuela, los tepuyes de Venezuela y Guyana y la región amazónica de Colombia, Venezuela y Brasil, y regiones de alta montaña como los páramos de Costa Rica, Colombia, Venezuela, Ecuador y Perú. Estudios recientes con base en especies brasileñas y caracteres tanto morfológicos como anatómicos, sugieren que Paepalanthus es un grupo polifilético. El presente estudio se realizó con el propósito de integrar en un análisis filogenético tanto especies de zonas altas como de zonas bajas de Paepalanthus con el fin de evaluar la monofilia del grupo mediante un muestreo más riguroso, y de explorar las posibles relaciones biogeográficas de las especies de páramo. Los resultados confirman que Paepalanthus es un grupo polifilético, con P. saxicola en la
    base de las eriocaulaceae muestreadas, seguida por un grado conformado en su orden por especies de Philodice, Leiothrix y Blastocaulon. Enseguida, se encuentra el clado mayor formado por un subclado donde están (P. subtilis (P. barkleyi-P. lamarckii-P. tortilis. El segundo subclado presenta a P. fasciculatus en la base, seguida de dos subclados menores, uno de ellos conformado por especies de Paepalanthus, Tonina y Lachnocaulon, y el otro por especies de los géneros Actinocephalus, Leiothrix, Syngonanthus, Eriocaulon y la mayoría de las especies de Paepalanthus propias de los páramos. De esta forma, el subgénero Psilandra representado por la especie P. saxicola se propone como el más basal y el subgénero Platycaulon, que resulta monofilético con el muestreo disponible, es el grupo más anidado dentro de la

  6. Fossil worm burrows reveal very early terrestrial animal activity and shed light on trophic resources after the end-cretaceous mass extinction. (United States)

    Chin, Karen; Pearson, Dean; Ekdale, A A


    The widespread mass extinctions at the end of the Cretaceous caused world-wide disruption of ecosystems, and faunal responses to the one-two punch of severe environmental perturbation and ecosystem collapse are still unclear. Here we report the discovery of in situ terrestrial fossil burrows from just above the impact-defined Cretaceous-Paleogene (K/Pg) boundary in southwestern North Dakota. The crisscrossing networks of horizontal burrows occur at the interface of a lignitic coal and silty sandstone, and reveal intense faunal activity within centimeters of the boundary clay. Estimated rates of sedimentation and coal formation suggest that the burrows were made less than ten thousand years after the end-Cretaceous impact. The burrow characteristics are most consistent with burrows of extant earthworms. Moreover, the burrowing and detritivorous habits of these annelids fit models that predict the trophic and sheltering lifestyles of terrestrial animals that survived the K/Pg extinction event. In turn, such detritus-eaters would have played a critical role in supporting secondary consumers. Thus, some of the carnivorous vertebrates that radiated after the K/Pg extinction may owe their evolutionary success to thriving populations of earthworms. PMID:23951041

  7. High Rates of Species Accumulation in Animals with Bioluminescent Courtship Displays. (United States)

    Ellis, Emily A; Oakley, Todd H


    One of the great mysteries of evolutionary biology is why closely related lineages accumulate species at different rates. Theory predicts that populations undergoing strong sexual selection will more quickly differentiate because of increased potential for genetic isolation [1-6]. Whether or not these population genetic processes translate to more species at macroevolutionary scales remains contentious [7]. Here we show that lineages with bioluminescent courtship, almost certainly a sexually selected trait, have more species and faster rates of species accumulation than their non-luminous relatives. In each of ten distantly related animal lineages from insects, crustaceans, annelid worms, and fishes, we find more species in lineages with bioluminescent courtship compared to their sister groups. Furthermore, we find under a Yule model that lineages with bioluminescent courtship displays have significantly higher rates of species accumulation compared to a larger clade that includes them plus non-luminous relatives. In contrast, we do not find more species or higher rates in lineages that use bioluminescence for defense, a function presumably not under sexual selection. These results document an association between the origin of bioluminescent courtship and increased accumulation of species, supporting theory predicting sexual selection increases rates of speciation at macroevolutionary scales to influence global patterns of biodiversity. PMID:27345160

  8. Morphogenesis defects are associated with abnormal nervous system regeneration following roboA RNAi in planarians. (United States)

    Cebrià, Francesc; Newmark, Phillip A


    The process by which the proper pattern is restored to newly formed tissues during metazoan regeneration remains an open question. Here, we provide evidence that the nervous system plays a role in regulating morphogenesis during anterior regeneration in the planarian Schmidtea mediterranea. RNA interference (RNAi) knockdown of a planarian ortholog of the axon-guidance receptor roundabout (robo) leads to unexpected phenotypes during anterior regeneration, including the development of a supernumerary pharynx (the feeding organ of the animal) and the production of ectopic, dorsal outgrowths with cephalic identity. We show that Smed-roboA RNAi knockdown disrupts nervous system structure during cephalic regeneration: the newly regenerated brain and ventral nerve cords do not re-establish proper connections. These neural defects precede, and are correlated with, the development of ectopic structures. We propose that, in the absence of proper connectivity between the cephalic ganglia and the ventral nerve cords, neurally derived signals promote the differentiation of pharyngeal and cephalic structures. Together with previous studies on regeneration in annelids and amphibians, these results suggest a conserved role of the nervous system in pattern formation during blastema-based regeneration. PMID:17251262

  9. Reconfirmation of antimicrobial activity in the coelomic fluid of the earthworm Eisenia fetida andrei by colorimetric assay

    Indian Academy of Sciences (India)

    Weidong Pan; Xianghui Liu; Feng Ge; Tao Zheng


    A novel tetrazolium salt, 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulphophenyl)-2Htetrazolium (MTS) was used in the assessment of antimicrobial activity in earthworm in the presence of phenazine methosulphate (PMS) as an electron coupling reagent. This activity was purified from the coelomic fluid of the earthworm (ECF), Eisenia fetida andrei (Oligochaeta, Lumbricidae, annelids) using a series of column chromatography techniques and was tested against three Gram-negative strains of Escherichia coli, Pseudomonas aeruginosa, Aeromonas hydrophila and three Gram-positive strains of Staphylococcus aureus, Bacillus megaterium, Arthrobacter sp., respectively. Only the pigment-free eluate of coelomic fluid of the earthworm (ECFPE) showed activity against B. megaterium amongst three isolated active fractions. The anion (DEAE-52) exchange effluent of the ECFPE was reported to have the strongest activity against P. aeruginosa amongst the three active fractions. The 20% acetonitrile eluate (AE) by Sep-Pak C18 cartridge was also tested and showed fair resistance against E. coli, P. aeruginosa and Arthrobacter sp., respectively.

  10. Ecotoxicological evaluation of the short term effects of fresh and stabilized textile sludges before application in forest soil restoration

    International Nuclear Information System (INIS)

    The short term (eco)toxicity potential of fresh and stabilized textile sludges, as well as the short term (eco)toxicity of leachates obtained from both fresh and stabilized textile sludges, was evaluated by a battery of toxicity tests carried out with bacteria, algae, daphnids, fish, earthworms, and higher plants. The (eco)toxicological results showed that, after 120 d of stabilization, the experimental loading ratio of 25% sludge:75% soil (v/v) (equivalent to 64.4 ton/ha) did not significantly increase toxicity effects and increased significantly the biomass yield for earthworms and higher plants. The rank of biological sensitivity endpoints was: Algae ∼ Plant biomass > Plant germination ∼ Daphnids > Bacteria ∼ Fish > Annelids. The lack of short term toxicity effects and the stimulant effect observed with higher plants and earthworms are good indications of the fertilizer/conditioner potential of this industrial waste, which after stabilization can be used in the restoration of a non-productive forest soil. - Short term ecotoxicity evaluation of textile sludge showed that stabilized sludge can be used in the restoration of a non-productive forest soil

  11. Biodiversity of the white coral bank off Cape Santa Maria di Leuca (Mediterranean Sea): An update (United States)

    Mastrototaro, F.; D'Onghia, G.; Corriero, G.; Matarrese, A.; Maiorano, P.; Panetta, P.; Gherardi, M.; Longo, C.; Rosso, A.; Sciuto, F.; Sanfilippo, R.; Gravili, C.; Boero, F.; Taviani, M.; Tursi, A.


    The biodiversity of the Santa Maria di Leuca (SML) coral bank is summarized and its description is updated using data collected by means of underwater video systems, benthic samplers and fishing gears. A total of 222 living species have been recorded within the coral bank area in the depth range 280-1121 m. The most abundant benthic taxa recorded are Porifera (36 species) followed by Mollusca (35) and Cnidaria (31). The scleractinian corals Madrepora oculata and Lophelia pertusa are the main colonial species in the structure of the SML bank. Annelida, Crustacea and Bryozoa have been found with 24, 23 and 19 species, respectively. A total of 40 species of demersal fish have been recorded. Other faunal taxa were found with small numbers of species. One hundred and thirty-five species are new for the SML bank, 31 of which represent new records for the north-western Ionian Sea (2 Porifera, 17 Cnidaria, 1 Mollusca, 3 Annelida, 2 Crustacea, 4 Bryozoa and 4 Echinodermata). The finding of the annelid Harmothoë vesiculosa represents the first record for the Mediterranean Sea. The SML coral bank represents a biodiversity "hot-spot" on the bathyal bottoms of the Mediterranean Sea.

  12. The ascidian prophenoloxidase activating system

    Directory of Open Access Journals (Sweden)

    M Cammarata


    Full Text Available Phenoloxidases/tyrosinases initiate melanin synthesis in almost all organisms, and are involved in different biological activities such as the colour change of human hair and the browning or blackening of fruit skin etc. In many invertebrates, defence reactions are linked to phenoloxidase activity and/or melanization. Contacts with foreign molecules are able to trigger the prophenoloxidase (proPO system that requires serine protease cleavage for activating the zymogen to phenoloxidase (PO. It is generally accepted that the proPO system is fully expressed in arthropods, and, recently, progress in the regulation of crustacean and insect proPO activation steps have been achieved. After cells were stimulated by components of pathogen associated molecular pattern (PAMP, proPO activation takes place via zimogenic serine proteinase in turn activated by PAMPs followed by cascade, spatial and temporal control.The proPO activating system plays a defensive role in arthropods, molluscs, annelids, ascidians and the cephalochordate Branchiostoma belcheri.In the present paper, we report on ascidian proPO system and related molecules, with particular focus on the biochemical, cellular and molecular aspects of the Ciona intestinalis, proPO system of circulating hemocytes from naïve ascidians as well as of body wall following LPS inflammatory challenge.

  13. Review of experimental and natural invertebrate hosts of sealworm (Pseudoterranova decipiens and its distribution and abundance in macroinvertebrates in eastern Canada

    Directory of Open Access Journals (Sweden)

    David J Marcogliese


    Full Text Available Experimental and natural invertebrate intermediate hosts of sealworm (Pseudoterranova decipiens as well as transmission experiments of sealworm from invertebrates to fish are reviewed and summarized. Experimental hosts include copepods, mysids, cumaceans, isopods, amphipods, decapods, annelids, and molluscs. Invertebrates collected from eastern Canada between 1989 and 1995 were checked for nematode infections by microscopic examination of dissected animals or enzymatic digestion of bulk samples. Third-stage larval sealworm were found in mysids (Neomysis americana, Mysis stenolepis from Passamaquoddy Bay, the Bras d’Or Lakes, inshore Cape Breton, Sable Island and Sable Island Bank. Infected amphipods (Amphiporeia virginiana, Americorchestia megalophthalma, Gammarus spp. were found only on Sable Island. Typical infection rates in macroinvertebrates were 1-4/1000. No sealworm infections were found in approximately 18,000 amphipods examined from Sable Island Bank, the site of the most heavily infected fishes in eastern Canada. In Wallace Lake, a brackish pond on Sable Island, infection rates were much higher in mysids than in amphipods. Estimates of rates of transmission of sealworm from invertebrates to fish were derived from infection levels in Wallace Lake and feeding experiments involving sticklebacks and invertebrate prey. It is concluded that mysids may be much more important than amphipods in transmitting sealworm to fish hosts.

  14. Proteomic Changes Associated with Successive Reproductive Periods in Male Polychaetous Neanthes arenaceodentata

    KAUST Repository

    Chandramouli, Kondethimmanahalli


    The polychaetous annelid Neanthes acuminata complex has a widespread distribution, with the California population referred to as N. arenaceodentata. The reproductive pattern in this complex is unique, in that the female reproduces once and then dies, whereas the male can reproduce up to nine times. The male incubates the embryos until the larvae leave the male’s tube 21–28 days later and commences feeding. Reproductive success and protein expression patterns were measured over the nine reproductive periods. The percent success of the male in producing juveniles increased during the first three reproductive periods and then decreased, but the number of juveniles produced was similar through all nine periods. iTRAQ based quantitative proteomics were used to analyze the dynamics of protein expression patterns. The expression patterns of several proteins were found to be altered. The abundant expression of muscular and contractile proteins may have affected body weight and reproductive success. Sperm have never been observed; fertilization occurs within the parent’s tube. Proteins associated with sperm maturation and fertilization were identified, including ATPase, clathrin, peroxiredoxins and enolase, which may provide clues to the molecular mechanisms enabling males to reproduce multiple times.

  15. Genetic assessment of meiobenthic community composition and spatial distribution in coastal sediments along northern Gulf of Mexico. (United States)

    Brannock, Pamela M; Wang, Lei; Ortmann, Alice C; Waits, Damien S; Halanych, Kenneth M


    Meiobenthic (meiofauna and micro-eukaryotes) organisms are important contributors to ecosystem functioning in aquatic environments through their roles in nutrient transport, sediment stability, and food web interactions. Despite their ecological importance, information pertaining to variation of these communities at various spatial and temporal scales is not widely known. Many studies in the Gulf of Mexico (GOM) have focused either on deep sea or continental shelf areas, while little attention has been paid to bays and coastal regions. Herein, we take a holistic approach by using high-throughput sequencing approaches to examine spatial variation in meiobenthic communities within Alabama bays and the coastal northern GOM region. Sediment samples were collected along three transects (Mississippi Sound: MS, FOCAL: FT, and Orange Beach: OB) from September 2010 to April 2012 and community composition was determined by metabarcoding the V9 hypervariable region of the nuclear18S rRNA gene. Results showed that Stramenopiles (diatoms), annelids, arthropods (copepods), and nematodes were the dominate groups within samples, while there was presence of other phyla throughout the dataset. Location played a larger role than time sampled in community composition. However, samples were collected over a short temporal scale. Samples clustered in reference to transect, with the most eastern transect (OB) having a distinct community composition in comparison to the other two transects (MS and FT). Communities also differed in reference to region (Bay versus Shelf). Bulk density and percent inorganic carbon were the only measured environmental factors that were correlated with community composition. PMID:27299291

  16. Shape optimization of a sheet swimming over a thin liquid layer

    Energy Technology Data Exchange (ETDEWEB)

    Wilkening, J.; Hosoi, A.E.


    Motivated by the propulsion mechanisms adopted by gastropods, annelids and other invertebrates, we consider shape optimization of a flexible sheet that moves by propagating deformation waves along its body. The self-propelled sheet is separated from a rigid substrate by a thin layer of viscous Newtonian fluid. We use a lubrication approximation to model the dynamics and derive the relevant Euler-Lagrange equations to simultaneously optimize swimming speed, efficiency and fluid loss. We find that as the parameters controlling these quantities approach critical values, the optimal solutions become singular in a self-similar fashion and sometimes leave the realm of validity of the lubrication model. We explore these singular limits by computing higher order corrections to the zeroth order theory and find that wave profiles that develop cusp-like singularities are appropriately penalized, yielding non-singular optimal solutions. These corrections are themselves validated by comparison with finite element solutions of the full Stokes equations, and, to the extent possible, using recent rigorous a-priori error bounds.

  17. Charles Darwin's Observations on the Behaviour of Earthworms and the Evolutionary History of a Giant Endemic Species from Germany, Lumbricus badensis (Oligochaeta: Lumbricidae)

    International Nuclear Information System (INIS)

    The British naturalist Charles Darwin (1809/1882) began and ended his almost 45-year-long career with observations, experiments, and theories related to earthworms. About six months before his death, Darwin published his book on The Formation of Vegetable Mould, through the Actions of Worms, With Observations on their Habits (1881). Here we describe the origin, content, and impact of Darwin's last publication on earthworms (subclass Oligochaeta, family Lumbricidae) and the role of these annelids as global ecosystem re workers (concept of bioturbation). In addition, we summarize our current knowledge on the reproductive behaviour of the common European species Lumbricus terrestris. In the second part of our account we describe the biology and evolution of the giant endemic species L. badensis from south western Germany with reference to the principle of niche construction. Bio geographic studies have shown that the last common ancestor of L. badensis, and the much smaller sister-taxon, the Atlantic-Mediterranean L. friendi, lived less than 10000 years ago. Allopatric speciation occurred via geographically isolated founder populations that were separated by the river Rhine so that today two earthworm species exist in different areas.

  18. Tetractinomyxon stages genetically consistent with Sphaerospora dicentrarchi (Myxozoa: Sphaerosporidae) found in Capitella sp. (Polychaeta: Capitellidae) suggest potential role of marine polychaetes in parasite's life cycle. (United States)

    Rangel, Luis F; Castro, Ricardo; Rocha, Sónia; Severino, Ricardo; Casal, Graça; Azevedo, Carlos; Cavaleiro, Francisca; Santos, Maria J


    Known life cycles of myxosporean parasites have two hosts, but very few life cycles have been disclosed, especially in the marine environment. Sphaerospora dicentrarchi Sitjà-Bobadilla and Álvarez-Pellitero, 1992 is a systemic parasite from the European seabass, Dicentrarchus labrax (Linnaeus, 1758), a highly valuable commercial fish. It affects its health, leading to aquaculture production losses. During 2013 and 2014, an actinospore survey was conducted in a total of 5942 annelids collected from a fish farm in Algarve and from the Aveiro Estuary, in Portugal. A new tetractinomyxon actinospore was found in a capitellid polychaete, belonging to the genera Capitella collected at the fish farm. The tetractinomyxons were pyriform measuring 11·1 ± 0·7 µm in length and 7·2 ± 0·4 µm in width, and presented three rounded polar capsules measuring 2·4 ± 0·3 µm in diameter. The molecular analysis of the 18S rRNA gene sequences from the tetractinomyxons revealed a similarity of 100% with the DNA sequences deposited in the GenBank from S. dicentrarchi myxospores collected from the European seabass and the spotted seabass in the same fish farm and 99·9% similarity with the DNA sequence obtained from the myxospores found infecting the European seabass in the Aveiro Estuary. Therefore, the new tetractinomyxons are inferred to represent the actinospore phase of the S. dicentrarchi life cycle. PMID:27041279

  19. Pyrosequencing assessment of prokaryotic and eukaryotic diversity in biofilm communities from a French river. (United States)

    Bricheux, Geneviève; Morin, Loïc; Le Moal, Gwenaël; Coffe, Gérard; Balestrino, Damien; Charbonnel, Nicolas; Bohatier, Jacques; Forestier, Christiane


    Despite the recent and significant increase in the study of aquatic microbial communities, little is known about the microbial diversity of complex ecosystems such as running waters. This study investigated the biodiversity of biofilm communities formed in a river with 454 Sequencing™. This river has the particularity of integrating both organic and microbiological pollution, as receiver of agricultural pollution in its upstream catchment area and urban pollution through discharges of the wastewater treatment plant of the town of Billom. Different regions of the small subunit (SSU) ribosomal RNA gene were targeted using nine pairs of primers, either universal or specific for bacteria, eukarya, or archaea. Our aim was to characterize the widest range of rDNA sequences using different sets of polymerase chain reaction (PCR) primers. A first look at reads abundance revealed that a large majority (47-48%) were rare sequences (<5 copies). Prokaryotic phyla represented the species richness, and eukaryotic phyla accounted for a small part. Among the prokaryotic phyla, Proteobacteria (beta and alpha) predominated, followed by Bacteroidetes together with a large number of nonaffiliated bacterial sequences. Bacillariophyta plastids were abundant. The remaining bacterial phyla, Verrucomicrobia and Cyanobacteria, made up the rest of the bulk biodiversity. The most abundant eukaryotic phyla were annelid worms, followed by Diatoms, and Chlorophytes. These latter phyla attest to the abundance of plastids and the importance of photosynthetic activity for the biofilm. These findings highlight the existence and plasticity of multiple trophic levels within these complex biological systems. PMID:23520129

  20. Interplay between a Wnt-dependent organiser and the Notch segmentation clock regulates posterior development in Periplaneta americana

    Directory of Open Access Journals (Sweden)

    John E. Chesebro


    Sequential addition of segments in the posteriorly growing end of the embryo is a developmental mechanism common to many bilaterians. However, posterior growth and patterning in most animals also entails the establishment of a ‘posterior organiser’ that expresses the Caudal and Wnt proteins and has been proposed to be an ancestral feature of animal development. We have studied the functional relationships between the Wnt-driven organiser and the segmentation mechanisms in a basal insect, the cockroach Periplaneta americana. Here, posteriorly-expressed Wnt1 promotes caudal and Delta expression early in development to generate a growth zone from which segments will later bud off. caudal maintains the undifferentiated growth zone by dampening Delta expression, and hence Notch-mediated segmentation occurs just outside the caudal domain. In turn, Delta expression maintains Wnt1, maintaining this posterior gene network until all segments have formed. This feedback between caudal, Wnt and Notch-signalling in regulating growth and segmentation seems conserved in other arthropods, with some aspects found even in vertebrates. Thus our findings not only support an ancestral Wnt posterior organiser, but also impinge on the proposals for a common origin of segmentation in arthropods, annelids and vertebrates.

  1. Bone-eating Osedax worms lived on Mesozoic marine reptile deadfalls. (United States)

    Danise, Silvia; Higgs, Nicholas D


    We report fossil traces of Osedax, a genus of siboglinid annelids that consume the skeletons of sunken vertebrates on the ocean floor, from early-Late Cretaceous (approx. 100 Myr) plesiosaur and sea turtle bones. Although plesiosaurs went extinct at the end-Cretaceous mass extinction (66 Myr), chelonioids survived the event and diversified, and thus provided sustenance for Osedax in the 20 Myr gap preceding the radiation of cetaceans, their main modern food source. This finding shows that marine reptile carcasses, before whales, played a key role in the evolution and dispersal of Osedax and confirms that its generalist ability of colonizing different vertebrate substrates, like fishes and marine birds, besides whale bones, is an ancestral trait. A Cretaceous age for unequivocal Osedax trace fossils also dates back to the Mesozoic the origin of the entire siboglinid family, which includes chemosynthetic tubeworms living at hydrothermal vents and seeps, contrary to phylogenetic estimations of a Late Mesozoic-Cenozoic origin (approx. 50-100 Myr). PMID:25878047

  2. Osedax borings in fossil marine bird bones (United States)

    Kiel, Steffen; Kahl, Wolf-Achim; Goedert, James L.


    The bone-eating marine annelid Osedax consumes mainly whale bones on the deep-sea floor, but recent colonization experiments with cow bones and molecular age estimates suggesting a possible Cretaceous origin of Osedax indicate that this worm might be able grow on a wider range of substrates. The suggested Cretaceous origin was thought to imply that Osedax could colonize marine reptile or fish bones, but there is currently no evidence that Osedax consumes bones other than those of mammals. We provide the first evidence that Osedax was, and most likely still is, able to consume non-mammalian bones, namely bird bones. Borings resembling those produced by living Osedax were found in bones of early Oligocene marine flightless diving birds (family Plotopteridae). The species that produced these boreholes had a branching filiform root that grew to a length of at least 3 mm, and lived in densities of up to 40 individuals per square centimeter. The inclusion of bird bones into the diet of Osedax has interesting implications for the recent suggestion of a Cretaceous origin of this worm because marine birds have existed continuously since the Cretaceous. Bird bones could have enabled this worm to survive times in the Earth's history when large marine vertebrates other than fish were rare, specifically after the disappearance of large marine reptiles at the end-Cretaceous mass extinction event and before the rise of whales in the Eocene.

  3. Cloning, Expression and Activity Analysis of a Novel Fibrinolytic Serine Protease fromArenicola cristata

    Institute of Scientific and Technical Information of China (English)

    ZHAO Chunling; JU Jiyu


    The full-length cDNA of a protease gene from a marine annelid Arenicola cristata was amplified through rapid amplifi-cation of cDNA ends technique and sequenced. The size of the cDNA was 936 bp in length, including an open reading frame encod-ing a polypeptide of 270 amino acid residues. The deduced amino acid sequnce consisted of pro- and mature sequences. The protease belonged to the serine protease family because it contained the highly conserved sequence GDSGGP. This protease was novel as it showed a low amino acid sequence similarity (<40%) to other serine proteases. The gene encoding the active form ofA. cristata serine protease was cloned and expressed inE. coli. Purified recombinant protease in a supernatant could dissolve an artificial fibrin plate with plasminogen-rich fibrin, whereas the plasminogen-free fibrin showed no clear zone caused by hydrolysis. This result sug-gested that the recombinant protease showed an indirect fibrinolytic activity of dissolving fibrin, and was probably a plasminogen activator. A rat model with venous thrombosis was established to demonstrate that the recombinant protease could also hydrolyze blood clotin vivo. Therefore, this recombinant protease may be used as a thrombolytic agent for thrombosis treatment. To our knowledge, this study is the first of reporting the fibrinolytic serine protease gene inA. cristata.

  4. Characterization of GnRH-related peptides from the Pacific oyster Crassostrea gigas. (United States)

    Bigot, Laetitia; Zatylny-Gaudin, Céline; Rodet, Franck; Bernay, Benoit; Boudry, Pierre; Favrel, Pascal


    Gonadotropin-releasing hormone (GnRH), a key neuropeptide regulating reproduction in vertebrates has now been characterized in a number of non-vertebrate species. Despite the demonstration of its ancestral origin, the structure and the function of this family of peptides remain poorly known in species as distant as lophotrochozoans. In this study, two GnRH-related peptides (Cg-GnRH-a and CgGnRH-G) were characterized by mass spectrometry from extracts of the visceral ganglia of the Pacific oyster Crassostrea gigas. These peptides showed a high degree of sequence identity with GnRHs of other mollusks and annelids and to a lesser extent with those of vertebrates or with AKH and corazonins of insects. Both the mature peptides and the transcript encoding the precursor protein were exclusively expressed in the visceral ganglia. Significant differences in transcriptional activity of Cg-GnRH encoding gene were recorded in the ganglia along the reproductive cycle and according to trophic conditions with a higher level in fed animals compared to starved animals. This suggests the involvement of Cg-GnRHs as synchronizers of nutritional status with energy requirements during reproduction in oyster. Evidence for a role of Cg-GnRHs as neuroregulators and as neuroendocrine factors in bivalve is discussed. PMID:22306476

  5. Leech therapeutic applications

    Directory of Open Access Journals (Sweden)

    A M Abdualkader


    Full Text Available Hematophagous animals including leeches have been known to possess biologically active compounds in their secretions, especially in their saliva. The blood-sucking annelids, leeches have been used for therapeutic purposes since the beginning of civilization. Ancient Egyptian, Indian, Greek and Arab physicians used leeches for a wide range of diseases starting from the conventional use for bleeding to systemic ailments, such as skin diseases, nervous system abnormalities, urinary and reproductive system problems, inflammation, and dental problems. Recently, extensive researches on leech saliva unveiled the presence of a variety of bioactive peptides and proteins involving antithrombin (hirudin, bufrudin, antiplatelet (calin, saratin, factor Xa inhibitors (lefaxin, antibacterial (theromacin, theromyzin and others. Consequently, leech has made a comeback as a new remedy for many chronic and life-threatening abnormalities, such as cardiovascular problems, cancer, metastasis, and infectious diseases. In the 20 th century, leech therapy has established itself in plastic and microsurgery as a protective tool against venous congestion and served to salvage the replanted digits and flaps. Many clinics for plastic surgery all over the world started to use leeches for cosmetic purposes. Despite the efficacious properties of leech therapy, the safety, and complications of leeching are still controversial.

  6. Three-dimensional reconstruction by cryoelectron microscopy of the giant hemoglobin of the polychaete worm Alvinella pompejana. (United States)

    de Haas, F; Zal, F; You, V; Lallier, F; Toulmond, A; Lamy, J N


    A frozen-hydrated specimen of the hexagonal bilayer hemoglobin (HBL Hb) from the deep-sea hydrothermal vent polychaete worm Alvinella pompejana, the most thermophilic metazoan known to date, was observed in the electron microscope and subjected to three-dimensional (3D) reconstruction by the method of random conical tilt series. At a resolution of 34.6 A by the differential phase residual method and 27.7 A by the Fourier shell correlation method, the 3D volume possesses a D6 point-group symmetry. While in previous 3D reconstructions of annelid and vestimentiferan Hbs the vertices of the upper layer were 16 degrees rotated compared with those of the lower layer, in Alvinella Hb the vertices of the two hexagonal layers are almost perfectly eclipsed when viewed along the 6-fold axis. As in the HBL Hbs of Riftia pachyptila and Macrobdella decora, a central linker complex is decorated by 12 hollow globular substructures (HGS). The linker complex comprises (1) a central hexagonal toroid, (2) two internal bracelets onto which the HGSs are built, and (3) six connections between the two hexagonal layers. Each HGS is composed of six masses, which are separated when the volume is displayed at high threshold, plus one additional mass involved in the bracelet connecting the six HGSs in both hexagonal layers. The HGSs have a local pseudo 3-fold symmetry and a disposition of the high-density masses different from those of Riftia V1 Hb. PMID:8950271

  7. The multi-hemoglobin system of the hydrothermal vent tube worm Riftia pachyptila. I. Reexamination of the number and masses of its constituents. (United States)

    Zal, F; Lallier, F H; Wall, J S; Vinogradov, S N; Toulmond, A


    The deep-sea tube worm Riftia pachyptila Jones possesses a well developed circulatory system and a large coelomic compartment, both containing extracellular hemoglobins. Fresh vascular blood is heterogeneous and contains two different hemoglobins (V1 and V2), whereas the coelomic fluid is homogeneous and comprises only one hemoglobin (C1). Their molecular weights have been determined by scanning transmission electron microscopy mass mapping (STEM) and by multi-angle laser light scattering (MALLS). Both methods yielded approximately the same molecular weights with masses significantly higher than the literature data for V1. V1, V2, and C1 had Mr of 3396 +/- 540 x 10(3), 393 +/- 71 x 10(3), and 410 +/- 51 x 10(3) by STEM, and 3503 +/- 13 x 10(3), 433 +/- 8 x 10(3), and 380 +/- 4 x 10(3) by MALLS, respectively. Transmission electron micrographs of V1 are typical of an hexagonal bilayer hemoglobin (HBL Hb). When submitted to dilution or osmotic shock, V1 dissociates into halves and one-twelfth subunits like annelid HBL Hbs. V1 is resistant to urea treatment, indicating that hydrophobic interactions play a small role in its quaternary structure. Conversely, V1 Hb is rather unstable in solution without denaturant, a property which seems to be characteristic of vestimentiferan HBL Hbs and could be explained by an important number of hydrogen bonds. PMID:8621528


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    Adesh Kumar


    Full Text Available Diversity refers variety in nature i.e. the variety of life on Earth and its biological diversity is commonly referred to as biodiversity. Sandi Bird sanctuary was developed and conserved in the year 1990 as natural biodiversity hub for aquatic vegetation as well as local residents and migratory birds. This Sanctuary has an area of 309 hectares. A study of faunal diversity in Sandi Bird Sanctuary was done during January 2013 to March 2014. Sandi Bird Sanctuary is well known as popular tourist destination because of the diverse assemblage of avifauna especially migratory water birds that congregate at the Sandi Bird Sanctuary in winter. The result includes 3 species of annelids belonging to 3 orders, 10 orders of insects with 61 species, 4 species of mollusks belonging to 3 orders, 11 species of fishes belonging to 5 families, 3 species of amphibians and 15 species of reptiles belonging to 13 families, 157 species of birds, and 12 species of mammals belonging to 09 families from Sandi Bird Sanctuary. The sanctuary is an envoy area of the Indo-gangetic eco-system. Wetland vegetation is also found in the sanctuary.

  9. Phylogeny of forkhead genes in three spiralians and their expression in Pacific oyster Crassostrea gigas (United States)

    Yang, Mei; Xu, Fei; Liu, Jun; Que, Huayong; Li, Li; Zhang, Guofan


    The Fox genes encode a group of transcription factors that contain a forkhead domain, which forms a structure known as a winged helix. These transcription factors play a crucial role in several key biological processes, including development. High-degree identity in the canonical forkhead domain has been used to divide Fox proteins into 23 families (FoxA to FoxS). We surveyed the genome of three spiralians, the oyster Crassostrea gigas, the limpet Lottia gigantea, and the annelid Capitella teleta. We identified 25 C. gigas fox genes, 21 L. gigantea fox genes, and 25 C. teleta fox genes. The C. gigas fox and L. gigantea fox genes represented 19 of the 23 families, whereas FoxI, Q1, R, and S were missing. The majority of the Fox families were observed within the C. teleta fox genes, with the exception of FoxR and S. In addition, the foxAB-like gene, foxY-like gene, and foxH gene were also present in the three genomes. The conserved FoxC-FoxL1 cluster, observed in mammals, was also found in C. gigas. The diversity of temporal expression patterns observed across the developmental process implies the C. gigas fox genes exert a wide range of functions. Further functional studies are required to gain insight into the evolution of Fox genes in bilaterians.

  10. Phylogeny and mitochondrial gene order variation in Lophotrochozoa in the light of new mitogenomic data from Nemertea

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    von Döhren Jörn


    Full Text Available Abstract Background The new animal phylogeny established several taxa which were not identified by morphological analyses, most prominently the Ecdysozoa (arthropods, roundworms, priapulids and others and Lophotrochozoa (molluscs, annelids, brachiopods and others. Lophotrochozoan interrelationships are under discussion, e.g. regarding the position of Nemertea (ribbon worms, which were discussed to be sister group to e.g. Mollusca, Brachiozoa or Platyhelminthes. Mitochondrial genomes contributed well with sequence data and gene order characters to the deep metazoan phylogeny debate. Results In this study we present the first complete mitochondrial genome record for a member of the Nemertea, Lineus viridis. Except two trnP and trnT, all genes are located on the same strand. While gene order is most similar to that of the brachiopod Terebratulina retusa, sequence based analyses of mitochondrial genes place nemerteans close to molluscs, phoronids and entoprocts without clear preference for one of these taxa as sister group. Conclusion Almost all recent analyses with large datasets show good support for a taxon comprising Annelida, Mollusca, Brachiopoda, Phoronida and Nemertea. But the relationships among these taxa vary between different studies. The analysis of gene order differences gives evidence for a multiple independent occurrence of a large inversion in the mitochondrial genome of Lophotrochozoa and a re-inversion of the same part in gastropods. We hypothesize that some regions of the genome have a higher chance for intramolecular recombination than others and gene order data have to be analysed carefully to detect convergent rearrangement events.

  11. Active microrheology reveals molecular-level variations in the viscoelastic properties of Chaetopterus mucus (United States)

    Weigand, William; Messmore, Ashley; Anderson, Rae

    The sea annelid, Chaetopterus Variopedatus, secretes a bioluminescent mucus that also exhibits complex viscoelastic properties. The constituents of the mucus are relatively unknown but it does play an important role in the development of the worms' parchment-like housing tubes. In order to determine how and why this mucus can exhibit material properties ranging from fluidity to rigidity we perform microrheology experiments. We determine the microscale viscoelastic properties by using optical tweezers to produce small oscillations in the mucus which allow us to determine both the linear storage and loss moduli (G',G'') along with the viscosity of the fluid. By varying the size of the microspheres (2-10 µm) and oscillation amplitude (.5-10 µm) we are able to determine the dominant intrinsic length scales of the molecular mesh comprising the mucus. By varying the oscillation frequency (1-15Hz) we determine the crossover frequency at which G' surpasses G'', to quantify the longest relaxation time of the mesh network. Initial results show a strong dependence on bead size which indicate that the dominant entanglement lengthscale of the mucus mesh is ~5 um. Microspheres of this size exhibit a wide variety of stress responses in different regions of the mucus demonstrating the substantial microscale heterogeneity of the mucus. We carry out measurements on a population of worms of varying size and age to determine mucus variability between worms.

  12. Neuroanatomy of the vestimentiferan tubeworm Lamellibrachia satsuma provides insights into the evolution of the polychaete nervous system.

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    Norio Miyamoto

    Full Text Available Vestimentiferan tubeworms are marine invertebrates that inhabit chemosynthetic environments, and although recent molecular phylogenetic analyses have suggested that vestimentiferan tubeworms are derived from polychaete annelids, they show some morphological features that are different from other polychaetes. For example, vestimentiferans lack a digestive tract and have less body segments and comparative neuroanatomy can provide essential insight into the vestimentiferan body plan and its evolution. In the present study, we investigated the adult nervous system in the vestimentiferan Lamellibrachia satsuma using antibodies against synapsin, serotonin, FMRMamide and acetylated α-tubulin. We also examined the expressions of neural marker genes, elav and synaptotagmin to reveal the distribution of neuronal cell bodies. Brain anatomy shows simple organization in Lamellibrachia compared to other polychaetes. This simplification is probably due to the loss of the digestive tract, passing through the body between the brain and the subesophageal ganglion. In contrast, the ventral nerve cord shows a repeated organizational structure as in the other polychaetes, despite the absence of the multiple segmentation of the trunk. These results suggest that the brain anatomy is variable depending on the function and the condition of surrounding tissues, and that the formation of the rope ladder-like nervous system of the ventral nerve cord is independent from segmentation in polychaetes.

  13. Neurogenesis in the mossy chiton, Mopalia muscosa (Gould) (Polyplacophora): evidence against molluscan metamerism. (United States)

    Friedrich, Stefan; Wanninger, Andreas; Brückner, Martin; Haszprunar, Gerhard


    Neurogenesis in the chiton Mopalia muscosa (Gould, 1846) was investigated by applying differential interference contrast microscopy, semithin serial sectioning combined with reconstruction techniques, as well as confocal laser scanning microscopy for the detection of fluorescence-conjugated antibodies against serotonin and FMRFamide. The ontogeny of serotonergic nervous structures starts with cells of the apical organ followed by those of the cerebral commissure, whereas the serotonergic prototroch innervation, pedal system, and the lateral cords develop later. In addition, there are eight symmetrically arranged serotonergic sensory cells in the dorsal pretrochal area of the larva. FMRFamide-positive neural elements include the cerebral commissure, specific "ampullary" sensory cells in the pretrochal region, as well as the larval lateral and pedal system. In the early juvenile the cerebral system no longer stains with either of the two antibodies and the pedal system lacks anti-FMRFamide immunoreactivity. Outgroup comparison with all other molluscan classes and related phyla suggests that the cord-like, nonganglionized cerebral system in the Polyplacophora is a reduced condition rather than a primitive molluscan condition. The immunosensitivity of the pedal commissures develops from posterior to anterior, suggesting independent serial repetition rather than annelid-like conditions and there is no trace of true segmentation during nervous system development. Polyplacophoran neurogenesis and all other available data on the subject contradict the idea of a segmented molluscan stem species. PMID:12112126

  14. Chiton myogenesis: perspectives for the development and evolution of larval and adult muscle systems in molluscs. (United States)

    Wanninger, Andreas; Haszprunar, Gerhard


    We investigated muscle development in two chiton species, Mopalia muscosa and Chiton olivaceus, from embryo hatching until 10 days after metamorphosis. The anlagen of the dorsal longitudinal rectus muscle and a larval prototroch muscle ring are the first detectable muscle structures in the early trochophore-like larva. Slightly later, a ventrolaterally situated pair of longitudinal muscles appears, which persists through metamorphosis. In addition, the anlagen of the putative dorsoventral shell musculature and the first fibers of a muscular grid, which is restricted to the pretrochal region and consists of outer ring and inner diagonal muscle fibers, are generated. Subsequently, transversal muscle fibers form underneath each future shell plate and the ventrolateral enrolling muscle is established. At metamorphic competence, the dorsoventral shell musculature consists of numerous serially repeated, intercrossing muscle fibers. Their concentration into seven (and later eight) functional shell plate muscle bundles starts after the completion of metamorphosis. The larval prototroch ring and the pretrochal muscle grid are lost at metamorphosis. The structure of the apical grid and its atrophy during metamorphosis suggests ontogenetic repetition of (parts of) the original body-wall musculature of a proposed worm-shaped molluscan ancestor. Moreover, our data show that the "segmented" character of the polyplacophoran shell musculature is a secondary condition, thus contradicting earlier theories that regarded the Polyplacophora (and thus the entire phylum Mollusca) as primarily eumetameric (annelid-like). Instead, we propose an unsegmented trochozoan ancestor at the base of molluscan evolution. PMID:11748697

  15. Mesoderm patterning and morphogenesis in the polychaete Alitta virens (Spiralia, Annelida): Expression of mesodermal markers Twist, Mox, Evx and functional role for MAP kinase signaling. (United States)

    Kozin, Vitaly V; Filimonova, Daria A; Kupriashova, Ekaterina E; Kostyuchenko, Roman P


    Mesoderm represents the evolutionary youngest germ layer and forms numerous novel tissues in bilaterian animals. Despite the established conservation of the gene regulatory networks that drive mesoderm differentiation (e.g. myogenesis), mechanisms of mesoderm specification are highly variable in distant model species. Thus, broader phylogenetic sampling is required to reveal common features of mesoderm formation across bilaterians. Here we focus on a representative of Spiralia, the marine annelid Alitta virens, whose mesoderm development is still poorly investigated on the molecular level. We characterize three novel early mesodermal markers for A. virens - Twist, Mox, and Evx - which are differentially expressed within the mesodermal lineages. The Twist mRNA is ubiquitously distributed in the fertilized egg and exhibits specific expression in endomesodermal- and ectomesodermal-founder cells at gastrulation. Twist is expressed around the blastopore and later in a segmental metameric pattern. We consider this expression to be ancestral, and in support of the enterocoelic hypothesis of mesoderm evolution. We also revealed an early pattern of the MAPK activation in A. virens that is different from the previously reported pattern in spiralians. Inhibition of the MAPK pathway by U0126 disrupts the metameric Twist and Mox expression, indicating an early requirement of the MAPK cascade for proper morphogenesis of endomesodermal tissues. PMID:27000638

  16. Myxozoan infections of caecilians demonstrate broad host specificity and indicate a link with human activity. (United States)

    Hartigan, Ashlie; Wilkinson, Mark; Gower, David J; Streicher, Jeffrey W; Holzer, Astrid S; Okamura, Beth


    Myxozoans are parasitic cnidarians that infect a wide variety of hosts. Vertebrates typically serve as intermediate hosts whereas definitive hosts are invertebrates, including annelids and bryozoans. Myxozoans are known to exploit species in two of the three extant amphibian orders (Anura: frogs and toads; Caudata: newts and salamanders). Here we use museum collections to determine, to our knowledge for the first time, whether myxozoans also exploit the third amphibian order (Gymnophiona: caecilians). Caecilians are a poorly known group of limbless amphibians, the ecologies of which range from aquatic to fully terrestrial. We examined 12 caecilian species in seven families (148 individuals total) characterised by a diversity of ecologies and life histories. Using morphological and molecular surveys, we discovered the presence of the myxozoan Cystodiscus axonis in two South American species (one of seven examined families) of aquatic caecilians - Typhlonectes natans and Typhlonectes compressicauda. All infected caecilians had been maintained in captivity in the United Kingdom prior to their preservation. Cystodiscus axonis is known from several Australian frog species and its presence in caecilians indicates a capacity for infecting highly divergent amphibian hosts. This first known report of myxozoan infections in caecilians provides evidence of a broad geographic and host range. However, the source of these infections remains unknown and could be related to exposure in South America, the U.K. or to conditions in captivity. PMID:26945641

  17. Spiral cleavage and early embryology of a loxosomatid entoproct and the usefulness of spiralian apical cross patterns for phylogenetic inferences

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    Merkel Julia


    Full Text Available Abstract Background Among the four major bilaterian clades, Deuterostomia, Acoelomorpha, Ecdysozoa, and Lophotrochozoa, the latter shows an astonishing diversity of bodyplans. While the largest lophotrochozoan assemblage, the Spiralia, which at least comprises Annelida, Mollusca, Entoprocta, Platyhelminthes, and Nemertea, show a spiral cleavage pattern, Ectoprocta, Brachiopoda and Phoronida (the Lophophorata cleave radially. Despite a vast amount of recent molecular phylogenetic analyses, the interrelationships of lophotrochozoan phyla remain largely unresolved. Thereby, Entoprocta play a key role, because they have frequently been assigned to the Ectoprocta, despite their differently cleaving embryos. However, developmental data on entoprocts employing modern methods are virtually non-existent and the data available rely exclusively on sketch drawings, thus calling for thorough re-investigation. Results By applying fluorescence staining in combination with confocal microscopy and 3D-imaging techniques, we analyzed early embryonic development of a basal loxosomatid entoproct. We found that cleavage is asynchronous, equal, and spiral. An apical rosette, typical for most spiralian embryos, is formed. We also identified two cross-like cellular arrangements that bear similarities to both, a "molluscan-like" as well as an "annelid-like" cross, respectively. Conclusions A broad comparison of cleavage types and apical cross patterns across Lophotrochozoa shows high plasticity of these character sets and we therefore argue that these developmental traits should be treated and interpreted carefully when used for phylogenetic inferences.

  18. Benthos response following petroleum exploration in the southern Caspian Sea: Relating effects of nonaqueous drilling fluid, water depth, and dissolved oxygen. (United States)

    Tait, R D; Maxon, C L; Parr, T D; Newton, F C


    The effects of linear alpha olefin (LAO) nonaqueous drilling fluid on benthic macrofauna were assessed over a six year period at a southern Caspian Sea petroleum exploration site. A wide-ranging, pre-drilling survey identified a relatively diverse shelf-depth macrofauna numerically dominated by amphipods, cumaceans, and gastropods that transitioned to a less diverse assemblage dominated by hypoxia-tolerant annelid worms and motile ostracods with increasing depth. After drilling, a similar transition in macrofauna assemblage was observed with increasing concentration of LAO proximate to the shelf-depth well site. Post-drilling results were consistent with a hypothesis of hypoxia from microbial degradation of LAO, supported by the presence of bacterial mats and lack of oxygen penetration in surface sediment. Chemical and biological recoveries at ≥200m distance from the well site were evident 33months after drilling ceased. Our findings show the importance of monitoring recovery over time and understanding macrofauna community structure prior to drilling. PMID:27417570

  19. Parasitic infections in the Mediterranean needlefish Tylosurus acus imperialis (Teleostei:Belonidae) off Tunisian coast

    Institute of Scientific and Technical Information of China (English)

    Manel Châari; Lassâd Neifar


    Objective: To provide a current survey of parasitic infections in the Mediterranean needlefish Tylosurus acus imperialis (T. acus imperialis). The impact of host’s size and sex on some characteristics of the infection was also examined. Methods: Between 2004 and 2009, 126 specimens of T. acus imperialis were necropsied to study their parasites. Results: Fifteen species of metazoan parasites were collected including 3 monogeneans (Aspinatrium gallieni, Nudaciraxine imperium and Axinoides sp.), 4 digeneans (Lecithostaphylus tylosuri, Tetrochetus coryphaenae, Oesophagotrema mediterranea and Sclerodistomoides pacificus), 1 cestode (Ptychobothrium sp.), 3 copepods (Lernanthropus tylosuri, Caligodes laciniatus and Caligus sp.), 1 isopod (Irona nana), 1 acanthocephalan (Rhadinorhynchus sp.), 1 nematode (anisakid larvae) and 1 annelid (piscicolid). Cestoda Ptychobothrium sp. was the most frequent species (72%). Prevalence and abundance of infection with Ptychobothrium sp. and Rhadinorhynchus sp. were positively correlated with the total length of the host. Host’s sex did not seem to affect the infection parameters of parasites in T. acus imperialis. Conclusions: This study provides first information on parasitic infections in the Mediterranean needlefish T. acus imperialis off Tunisia. Parasites can be used to understand phylogeny, biology and ecology of fish host and also as bioindicators of water quality.

  20. Expression and characterization of a recombinant i-type lysozyme from the harlequin ladybird beetle Harmonia axyridis. (United States)

    Beckert, A; Wiesner, J; Schmidtberg, H; Lehmann, R; Baumann, A; Vogel, H; Vilcinskas, A


    Lysozymes are enzymes that destroy bacterial cell walls by hydrolysing the polysaccharide component of peptidoglycan. In insects, there are two classes of lysozymes, the c-type with muramidase activity and the i-type whose prototypical members from annelids and molluscs possess both muramidase and isopeptidase activities. Many insect genes encoding c-type and i-type lysozymes have been identified during genome and transcriptome analyses, but only c-type lysozymes have been functionally characterized at the protein level. Here we produced one of five i-type lysozymes represented in the immunity-related transcriptome of the invasive harlequin ladybird beetle Harmonia axyridis as recombinant protein. This was the only one containing the serine and histidine residues that are thought to be required for isopeptidase activity. This i-type lysozyme was recombinantly expressed in the yeast Pichia pastoris, but the purified protein was inactive in both muramidase and isopeptidase assays. Transcription and immunofluorescence analysis revealed that this i-type lysozyme is produced in the fat body but is not inducible by immune challenge. These data suggest that i-type lysozymes in insects may have acquired novel and as yet undetermined functions in the course of evolution. PMID:26778648

  1. Evolution of retinoic acid receptors and retinoic acid signaling. (United States)

    Gutierrez-Mazariegos, Juliana; Schubert, Michael; Laudet, Vincent


    Retinoic acid (RA) is a vitamin A-derived morphogen controlling important developmental processes in vertebrates, and more generally in chordates, including axial patterning and tissue formation and differentiation. In the embryo, endogenous RA levels are controlled by RA synthesizing and degrading enzymes and the RA signal is transduced by two retinoid receptors: the retinoic acid receptor (RAR) and the retinoid X receptor (RXR). Both RAR and RXR are members of the nuclear receptor superfamily of ligand-activated transcription factors and mainly act as heterodimers to activate the transcription of target genes in the presence of their ligand, all-trans RA. This signaling pathway was long thought to be a chordate innovation, however, recent findings of gene homologs involved in RA signaling in the genomes of a wide variety of non-chordate animals, including ambulacrarians (sea urchins and acorn worms) and lophotrochozoans (annelids and mollusks), challenged this traditional view and suggested that the RA signaling pathway might have a more ancient evolutionary origin than previously thought. In this chapter, we discuss the evolutionary history of the RA signaling pathway, and more particularly of the RARs, which might have experienced independent gene losses and duplications in different animal lineages. In sum, the available data reveal novel insights into the origin of the RA signaling pathway as well as into the evolutionary history of the RARs. PMID:24962881

  2. Identification, isolation and expansion of myoendothelial cells involved in leech muscle regeneration.

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    Annalisa Grimaldi

    Full Text Available Adult skeletal muscle in vertebrates contains myoendothelial cells that express both myogenic and endothelial markers, and which are able to differentiate into myogenic cells to contribute to muscle regeneration. In spite of intensive research efforts, numerous questions remain regarding the role of cytokine signalling on myoendothelial cell differentiation and muscle regeneration. Here we used Hirudo medicinalis (Annelid, leech as an emerging new model to study myoendothelial cells and muscle regeneration. Although the leech has relative anatomical simplicity, it shows a striking similarity with vertebrate responses and is a reliable model for studying a variety of basic events, such as tissue repair. Double immunohistochemical analysis were used to characterize myoendothelial cells in leeches and, by injecting in vivo the matrigel biopolymer supplemented with the cytokine Vascular Endothelial Growth Factor (VEGF, we were able to isolate this specific cell population expressing myogenic and endothelial markers. We then evaluated the effect of VEGF on these cells in vitro. Our data indicate that, similar to that proposed for vertebrates, myoendothelial cells of the leech directly participate in myogenesis both in vivo and in vitro, and that VEGF secretion is involved in the recruitment and expansion of these muscle progenitor cells.

  3. Mechanics of cocoon secretion in a segmented worm (Annelida: Hirudinidae). (United States)

    Rossi, Anthony M; Saidel, William M; Gravante, Christopher J; Sayers, Charlene W; Shain, Daniel H


    Clitellate annelids (e.g., segmented earthworms, leeches) secrete proteinaceous cocoons into which eggs are deposited. The process of cocoon production is characterized by the coordinated release of micro-granules from secretory cells positioned asymmetrically within the clitellum. Collectively, these assemble into a tubular cocoon sheath that is sealed at either end by globular opercula. By transmission electron microscopy (TEM), we show here that granules destined to the cocoon operculum in the leech, Erpodbdella obscura, display a series of concentric rings surrounding a structureless core with dimensions approximating a single nanoglobule found in the operculum. Upon their channeling to the surface through narrow tubules, granules are secreted into the cocoon lumen where they appear to fragment upon contact with the operculum matrix. The distribution of partial concentric ring structures throughout the operculum suggests that granular fusion causes dynamic fragmentation of outer surface material, which thereafter integrates into operculum nanoglobules and cavities. Other granules within the same secretory cell display a punctate pattern and likely fuse with the cocoon sheath prior to crystallization. PMID:27129037

  4. Guanidine hydrochloride and urea effects upon thermal stability of Glossoscolex paulistus hemoglobin (HbGp). (United States)

    Carvalho, Francisco A O; Alves, Fernanda R; Carvalho, José W P; Tabak, Marcel


    Glossoscolex paulistus hemoglobin (HbGp) has a molecular mass of 3600kDa. It belongs to the hexagonal bilayer hemoglobin class, which consists of highly cooperative respiratory macromolecules found in mollusks and annelids. The present work focusses on oxy-HbGp thermal stability, in the presence of urea and guanidine hydrochloride (GuHCl), monitored by several techniques. Initially, dynamic light scattering data show that the presence of GuHCl induces the protein oligomeric dissociation, followed by a significant 11-fold increase in the hydrodynamic diameter (DH) values, due to the formation of protein aggregates in solution. In contrast, urea promotes the HbGp oligomeric dissociation, followed by unfolding process at high temperatures, without aggregation. Circular dichroism data show that unfolding critical temperature (Tc) of oxy-HbGp decreases from 57°C, at 0.0 mol/L of the denaturant, to 45°C, in the presence of 3.5 mol/L of urea, suggesting the reduction of HbGp oligomeric stability. Moreover, differential scanning calorimetry results show that at lower GuHCl concentrations, some thermal stabilization of the hemoglobin is observed, whereas at higher concentrations, the reduction of stability takes place. Besides, HbGp is more stable in the presence of urea when compared with the guanidine effect, as deduced from the differences in the concentration range of denaturants. PMID:25433131

  5. Amyloid/Melanin distinctive mark in invertebrate immunity

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    A Grimaldi


    Full Text Available Protostomes and Deuterostomes show the same nexus between melanin production, and amyloid fibril production, i.e., the presence of melanin is indissolubly linked to amyloid scaffold that, in turn, is conditioned by the redox status/cytoplasmic pH modification, pro-protein cleavage presence, adrenocorticotropin hormone (ACTH, melanocyte-stimulating hormone (α-MSH, and neutral endopeptidase (NEP overexpressions. These events represent the crucial component of immune response in invertebrates, while in vertebrates these series of occurrences could be interpreted as a modest and very restricted innate immune response. On the whole, it emerges that the mechanisms involving amyloid fibrils/pigment synthesis in phylogenetically distant metazoan (viz, cnidaria, molluscs, annelids, insects, ascidians and vertebrates are evolutionary conserved. Furthermore, our data show the relationship between immune and neuroendocrine systems in amyloid/melanin synthesis. Indeed the process is closely associated to ACTH-α-MSH production, and their role in stress responses leading to pigment production reflects and confirms again their ancient phylogeny.

  6. Effective activation of antioxidant system by immune-relevant factors reversely correlates with apoptosis of Eisenia andrei coelomocytes. (United States)

    Homa, J; Stalmach, M; Wilczek, G; Kolaczkowska, E


    Oxidative stress is harmful to the microbes but also to the host, and may result in bystander damage or death. Because of this, respiratory burst triggered in phagocytes by pathogens is counteracted by production of antioxidative factors. The aim of this work was to examine effectiveness of the latter system in earthworms Eisenia andrei by induction of reactive oxygen species, lipofuscin and phenoloxidase by natural (LPS, zymosan, Micrococus luteus) and synthetic (phorbol ester, PMA) stimulants. The compounds impaired numbers, viability (increased apoptosis) and composition of coelomocytes, and triggered the antioxidant activity of catalase and selenium-dependent glutathione peroxidase. The natural pathogenic compounds, unlike PMA, strongly activated antioxidative responses that diminished cell apoptosis. Moreover, repeated exposure to the same or different pathogenic compounds did not induce respiratory burst exhausted phenotype showing that coelomocytes are constantly at bay to withstand numerous infections. The current study reveals importance and efficiency of the oxidative-antioxidative systems in annelids but also confirms its evolutionary conservatism and complexity even in lower taxa of the animal kingdom. PMID:26922789

  7. [Diversity, abundance and distribution of benthic macrofauna on rocky shores from North Sucre State, Venezuela]. (United States)

    Fernandez, Johanna; Jiménez, Mayré; Allen, Thays


    The rocky intertidal zone is among the most extreme physical environments on Earth. Organisms living in this area are constantly stricken by physico-chemical and biological factors. Due to the ecological importance of these areas, we studied the diversity, abundance and distribution of the rocky coastline benthic macrofauna, from the North coast of Sucre State, Venezuela. We performed bimonthly samplings from November 2008 to September 2009. The collection of biological material in the littoral zone (supra, mid and infralittoral) was done manually with a grid of 0.25m2. Organisms were preserved in 10% formalin for later identification and analysis (ecological parameters and Kruskal-Wallis test to the abundance and diversity). We found a total 19,020 organisms (86 spp.), in 8 phyla, 45 families and 47 genera. Mollusks were the most abundant and diverse (58 spp.), followed by arthropods (12 spp.), annelids (7 spp.), echinoderms (5 spp.), and the less represented cnidarians, sipunculids, nemertinids and urochordates (1 sp.). The zonation found coincided with the universal scheme of zonation. The towns of Rio Boca and Rio Caribe presented the highest values of ecological parameters, and the lowest were found in Playa Grande. Statistical significant differences were found in the abundance and diversity of macrofauna among the three zones. The little information on the composition and distribution of macrobenthic rocky coastline, prevents a better comparison, however the results contribute to the knowledge of the marine biodiversity in this region. PMID:25412527

  8. Radiation sensitivity and gene expression in Enchytraeus japonensis, a species of earth worm

    International Nuclear Information System (INIS)

    The importance of radiological protection of the environment based on scientific principles is gaining international recognition as environment issues garner more attention. Earthworm (annelids) is a ubiquitous soil invertebrate known to play an important role in the maintenance of the soil ecosystem and thus selected as one of 12 kinds of reference animals and plants by the ICRP. In the present study, radiation sensitivity and gene expression in a recently described terrestrial oligochaete, Enchytraeus japonensis (E. japonensis) were studied. E. japonensis worms were acutely irradiated at increasing doses of gamma radiation, and the number of worms after 30 days of radiation was examined. The dose effectively inhibiting 50% of proliferation was approximately 22 Gy, which was comparable to the dose required to elicit growth inhibition in other earthworm species. In order to seek other biological endpoints for more sensitive and/or quicker assessment of radiation effects, gene expression profiling in E. japonensis was also performed, and poly (ADP-ribose) polymerase I (PARP I) was identified as a radiation-responsive gene. PARP I transcript level increased dose-dependently. (author)

  9. Lineage analysis of micromere 4d, a super-phylotypic cell for Lophotrochozoa, in the leech Helobdella and the sludgeworm Tubifex. (United States)

    Gline, Stephanie E; Nakamoto, Ayaki; Cho, Sung-Jin; Chi, Candace; Weisblat, David A


    The super-phylum Lophotrochozoa contains the plurality of extant animal phyla and exhibits a corresponding diversity of adult body plans. Moreover, in contrast to Ecdysozoa and Deuterostomia, most lophotrochozoans exhibit a conserved pattern of stereotyped early divisions called spiral cleavage. In particular, bilateral mesoderm in most lophotrochozoan species arises from the progeny of micromere 4d, which is assumed to be homologous with a similar cell in the embryo of the ancestral lophotrochozoan, more than 650 million years ago. Thus, distinguishing the conserved and diversified features of cell fates in the 4d lineage among modern spiralians is required to understand how lophotrochozoan diversity has evolved by changes in developmental processes. Here we analyze cell fates for the early progeny of the bilateral daughters (M teloblasts) of micromere 4d in the leech Helobdella sp. Austin, a clitellate annelid. We show that the first six progeny of the M teloblasts (em1-em6) contribute five different sets of progeny to non-segmental mesoderm, mainly in the head and in the lining of the digestive tract. The latter feature, associated with cells em1 and em2 in Helobdella, is seen with the M teloblast lineage in a second clitellate species, the sludgeworm Tubifex tubifex and, on the basis of previously published work, in the initial progeny of the M teloblast homologs in molluscan species, suggesting that it may be an ancestral feature of lophotrochozoan development. PMID:21295566

  10. [Macrobenthos community structure and its relations with environmental factors in Taihu River basin]. (United States)

    Gao, Xin; Niu, Cui-Juan; Hu, Zhong-Jun


    An investigation was conducted on the macrobenthos at 37 sampling sites in the Taihu River basin in August 2009 and May 2010. A total of 69 macrobenthos species were collected, of which, 15 species (21.7% of the total) were oligochaetas, 16 species (23.2%) were mollusks, 5 species (7.2%) were crustaceans, 27 species (39.1%) were aquatic insects, and 6 species (8.7%) were polychaetes. Based on the species composition and relative abundance, and by using two-way indicators species analysis (TWINSPAN) and detrended correspondence analysis (DCA), the 37 sampling sites were divided into four groups. In the first group, polychaetes and mollusks such as Nephthys sp. and Corbicula fluminea were the indicator species; in the second group, polychaetes and mollusks such as Grandidierella aihuensis and Semisulcospira libertina were the indicator species; in the third and fourth groups, the indicator species were the annelids such as Limnodrilus hoffmeisteri and the Tubifex tubifex and chironomidae larvae, respectively. The canonical correspondence analysis (CCA) indicated that water conductivity and total nitrogen were the main environmental factors affecting the distribution of macrobenthos, and the factors water depth, diaphaneity, COD(Cr), ammonium nitrogen, nitrate nitrogen, and chlorophyll a also had definite effects. PMID:22384605

  11. The complete mitochondrial genome of Watersipora subtorquata (Bryozoa, Gymnolaemata, Ctenostomata) with phylogenetic consideration of Bryozoa. (United States)

    Sun, Ming'an; Wu, Zhigang; Shen, Xin; Ren, Jianfeng; Liu, Xixing; Liu, Huilian; Liu, Bin


    The phylogenetic position of the Bryozoa has long been controversial. In this paper, we have determined the complete mitochondrial genome of the Watersipora subtorquata (Bryozoa, Gymnolaemata, Ctenostomata). It is a circular molecule of 14,144 bp, relatively small compared with most other metazoan mitochondrial genomes, and bears some unusual features. All genes in the W. subtorquata mtDNA, unlike those in two bryozoan mtDNAs and most other metazoan mtDNAs published previously, are transcribed from the same strand. It has a unique gene order which differs radically from that of other metazoans. Drastic gene rearrangements were also found among bryozoan mtDNAs. To investigate the phylogenetic position of Bryozoa, analyses based on amino acid sequences of 11 protein-coding genes (excluding atp6 and atp8) from 25 metazoan mtDNAs were made utilizing ML and Bayesian methods. Lophotrochozoa was recovered as monophyletic with strong support in our analyses. Lophophorate was undoubted within Lophotrochozoa, but appears as polyphyletic, which indicates that the lophophores of this group may be of different origin. The existence of Phoronozoa was rejected. Our analyses indicated that Phoronida is more closely related to Annelid instead of Brachiopod. Chaetognatha appeared as the sister group of Bryozoa and they formed a clade together with strong support. More evidence is needed to clarify the relationship of these two phyla. PMID:19289161

  12. Cloning, expression and activity analysis of a novel fibrinolytic serine protease from Arenicola cristata (United States)

    Zhao, Chunling; Ju, Jiyu


    The full-length cDNA of a protease gene from a marine annelid Arenicola cristata was amplified through rapid amplification of cDNA ends technique and sequenced. The size of the cDNA was 936 bp in length, including an open reading frame encoding a polypeptide of 270 amino acid residues. The deduced amino acid sequnce consisted of pro- and mature sequences. The protease belonged to the serine protease family because it contained the highly conserved sequence GDSGGP. This protease was novel as it showed a low amino acid sequence similarity (cloned and expressed in E. coli. Purified recombinant protease in a supernatant could dissolve an artificial fibrin plate with plasminogen-rich fibrin, whereas the plasminogen-free fibrin showed no clear zone caused by hydrolysis. This result suggested that the recombinant protease showed an indirect fibrinolytic activity of dissolving fibrin, and was probably a plasminogen activator. A rat model with venous thrombosis was established to demonstrate that the recombinant protease could also hydrolyze blood clot in vivo. Therefore, this recombinant protease may be used as a thrombolytic agent for thrombosis treatment. To our knowledge, this study is the first of reporting the fibrinolytic serine protease gene in A. cristata.

  13. Ichnofossils and their significance in the Cambrian successions of the Parahio Valley in the Spiti Basin, Tethys Himalaya, India (United States)

    Parcha, S. K.; Pandey, Shivani


    The Spiti Basin exposes well preserved Cambrian successions in the Tethys Himalaya. The present ichnofossil assemblage is reported from the Debsakhad Member of the Kunzum La Formation. The ichnofossils includes the ichnogenera Bergaueria, Chondrites, Cruziana, Didymaulichnus, Dimorphichnus, Diplichnites, Helminthorhaphe, Merostomichnites, ?Monocraterion, Monomorphichnus, Nereites, Palaeopascichnus, Palaeophycus, Phycodes, Planolites, Rusophycus, Skolithos, Scolicia, Treptichnus, etc. along with annelid worm, burrow and scratch marks. These ichnogenera can be assigned to cubichnial, repichnial, pascichnial to fodinichnial behaviors. The ichnofossils reported from this section provide evidence regarding the developmental patterns during the early phase of life. In absence of trilobites, the present assemblage of ichnofossils is very significant in assigning the age of the Debsakhad Member. The abundance of ichnofossils in sandstone, siltstone and in shale beds indicate that the ichnocenosis is dominated by a high behavioral diversity ranging from the suspension to deposit feeders. Three lithofacies were observed in this section, they show a vertical disposition, which further reflects general upward coarsening trend. Ichnofossils are mostly produced by arthropods along with crustacean, polychaetes and polyphyletic vermiforms. Due to the paucity of body fossil, as well as microbiota in the lowermost beds of the Debsakhad Member, the Precambrian-Cambrian boundary could not be demarcated. However, the presence of Treptichnus and Phycodes can be considered as a horizon marker for the beginning of Lower Cambrian in this section.

  14. [Macrobenthic faunal diversity in Xiangshan Bay]. (United States)

    Gu, Xiao-Ying; Tao, Lei; Shi, Hui-Xiong; Lou, Dan; Jiao, Hai-Feng; You, Zhong-Jie


    In order to understand the community pattern and biodiversity of macrobenthic fauna in Xiangshan Bay, an eight cruises survey was made at thirteen stations of the Bay from July 2006 to August 2007, with the dominant species composition, richness, biomass, secondary productivity, and P/B value of macrobenthic fauna investigated, and the species diversity of the macrobenthic fauna analyzed. A total of 123 macrobenthos species were recorded, including 48 species Mollusc, 33 species Crustacea, 12 species fish, 12 species annelid polychaete, 8 species echinoderms, and some coelenterates and nematodes. The dominant species were more concentrated, and the dominance index was higher. The average secondary productivity of the macrobenthic fauna was 16.70 g x m(-2) x a(-1), and the average P/B value was 0.60. There existed distinct variations (P diversity index (D), and Shannon diversity index (H) among different survey stations, and distinct variations (P < 0.01) in the indices except evenness index (J) between years. PMID:20873634

  15. Preventing overexploitation in a mutualism: partner regulation in the crayfish-branchiobdellid symbiosis. (United States)

    Farrell, Kaitlin J; Creed, Robert P; Brown, Bryan L


    For a symbiosis to be a mutualism, benefits received must exceed costs incurred for both partners. Partners can prevent costly overexploitation through behaviors that moderate interactions with the other symbiont. In a symbiosis between crayfish and branchiobdellidan annelids, the worms can increase crayfish survival and growth by removing fouling material from the gills. However, overexploitation by the worms is possible and results in damage to host gills. We used behavioral observations to assess the degree to which two species of crayfish (Cambarus chasmodactylus and Orconectes cristavarius) use grooming to moderate their interaction with branchiobdellids. We found that grooming could effectively reduce worm numbers, and the proportion of total grooming directed at worms differed between crayfish species and as a function of worm number. O. cristavarius increased grooming in response to the addition of a single worm, while C. chasmodactylus only increased grooming in response to ten worms. These differences in the number of worms that trigger grooming behavior reflect differences between crayfish species in field settings. We also assessed whether antibacterial compounds in circulating crayfish hemolymph could limit bacterial gill fouling. O. cristavarius hemolymph inhibited some test bacteria more effectively than C. chasmodactylus did. Differences in the antibacterial properties of crayfish hemolymph may therefore help explain differences in both worm-directed grooming and worm loads in the field. We conclude that crayfish can use grooming to reduce worm numbers, which could lower the potential for gill damage, and that the level of grooming varies between crayfish species. PMID:24072440

  16. The use of lipid markers to define sources of organic matter in sediment and food web of the intertidal salt-marsh-flat ecosystem of Mont-Saint-Michel Bay, France (United States)

    Meziane, Tarik; Bodineau, Laurent; Retiere, Christian; Thoumelin, Guy


    Salt marsh plants and seven surface sediment samples along a transect in the intertidal flat area of Mont-Saint-Michel Bay were analysed for fatty acids and sterols. The presence of lipid markers of halophytes (long-chain fatty acids, 18:3ω3, and phytosterols) in the surface layers of the sediment confirms the export of organic matter from the salt marsh to the intertidal flat. The spatial distribution of this organic matter over the tidal-flat area was controlled by the tidal currents and the presence of mussel beds. Lipid markers of diatoms (20:5ω3 and brassicasterol) and bacteria (18:1ω7 and odd, linear and branched, fatty acids) were also found in the surface sediments. Diatoms and benthic bacteria as well as organic matter from the salt marsh were the significant food sources available to the macrozoobenthos on the intertidal flat. The ingestion of these food types by the dominant species of the macrozoobenthos was confirmed by the presence of their respective lipid markers in the animals. The presence of these markers in animals subjected to a starvation experiment confirmed that these food types are really assimilated. The lipid composition of the starved animals indicated that the species studied were able to accumulate the fatty acid 20:5ω3 (considered to be a diatom marker), and that the annelid Nereis diversicolor supported an internal bacterial population.

  17. Tolerance and biomarkers as useful tools for assessing environmental quality in the Oued Souss estuary (Bay of Agadir, Morocco). (United States)

    Ait Alla, A; Mouneyrac, C; Durou, C; Moukrim, A; Pellerin, J


    The aim of this study was to assess aquatic environmental quality of Oued Souss (Agadir, Morocco). This estuary has been subjected for a long time to large amounts of sewage discharges and industrial effluents. Since November 2002, no waste outlets have been discharged in this site due to their connection to a wastewater purification plant. Firstly, we have compared metal tolerance of the annelid polychaete (Nereis diversicolor) originating from Oued Souss and a relatively clean site (Oualidia, Morocco). Secondly, we have evaluated with a multi-marker approach (acetylcholinesterase [AChE], glutathione-S-transferases [GSTs], catalase, thiobarbituric acid reactive substances [TBARs]) responses of worms to the pollution gradient. Results have shown that worms from Oued Souss have acquired tolerance to copper and zinc due to a long-term sub-lethal metal exposure and this metal tolerance was maintained in spite of the end of wastewater discharges in this site. Higher catalase, GSTs and TBARs values have been observed in worms from Oued Souss sampled before implantation of wastewater treatment. The multi-marker approach confirms that these worms have been submitted to various contaminants. In contrast, high inhibition in AChE activities measured in worms from Oued Souss could be explained by the continuous agricultural influence of nearest areas. The level of contamination was probably maintained since biomarker values were generally higher in worms from Oued Souss when compared to Oualidia. PMID:16413830

  18. Characterization of a novel EF-hand homologue, CnidEF, in the sea anemone Anthopleura elegantissima. (United States)

    Hauck, Laura L; Phillips, Wendy S; Weis, Virginia M


    The superfamily of EF-hand proteins is comprised of a large and diverse group of proteins that contain one or more characteristic EF-hand calcium-binding domains. This study describes and characterizes a novel EF-hand cDNA, CnidEF, from the sea anemone Anthopleura elegantissima (Phylum Cnidaria, Class Anthozoa). CnidEF was found to contain two EF-hand motifs near the C-terminus of the deduced amino acid sequence and two regions near the N-terminus that could represent degenerate EF-hand motifs. CnidEF homologues were also identified from two other sea anemone species. A combination of bioinformatic and molecular phylogenetic analyses was used to compare CnidEF to EF-hand proteins in other organisms. The closest homologues identified from these analyses were a luciferin binding protein (LBP) involved in the bioluminescence of the anthozoan Renilla reniformis, and a sarcoplasmic calcium-binding protein (SARC) involved in fluorescence of the annelid worm Nereis diversicolor. Predicted structure and folding analysis revealed a close association with bioluminescent aequorin (AEQ) proteins from the hydrozoan cnidarian Aequorea aequorea. Neighbor-joining analyses grouped CnidEF within the SARC lineage along with AEQ and other cnidarian bioluminescent proteins rather than in the lineage containing calmodulin (CAM) and troponin-C (TNC). PMID:17280859

  19. Molecular cloning and characterization of a gene encoding a 13.1 kDa antigenic protein of Naegleria fowleri. (United States)

    Shin, H J; Cho, M S; Jung, S U; Kim, H I; Park, S; Kim, H J; Im, K I


    An antigen-related gene was cloned from a cDNA expression library of Naegleria fowleri by immunoscreening with sera obtained from mice that were either immunized with an amoebic lysate or infected with trophozoites. The coding nucleotide sequence of the cloned gene consisted of 357 bases that were translated into 119 amino acids. This gene was designated as nfa1. The predicted amino acid sequence of Nfa1 protein has two potential glycosylation and three potential phosphorylation sites, and its predicted secondary structure consists of four helices and three corners. The deduced amino acid sequence of Nfa1 protein shares 43% identity with the myohemerythrin (myoHr) protein from a marine annelid, Nereis diversicolor, including 100% identity in conserved regions and iron-binding residues. A phylogenetic tree constructed from amino acid sequences placed the N. fowleri Nfa1 protein outside of a cluster of myoHr proteins from eight invertebrates. A purified recombinant protein that migrated as a 13.1 kDa species in SDS-PAGE was produced. This recombinant protein exhibited a strong immunoreactivity with infected, immune, and anti-Nfal sera. In addition, an anti-Nfa1 serum reacted with an amoeba lysate in immunoblotting analysis. The present nfal gene encoding the myoHr-like protein is the first myoHr gene cloned from protozoa, and the Nfal antigen may be useful in diagnostic studies PMID:11831780

  20. Dynamic organization of microtubules and microtubule-organizing centers during the sexual phase of a parasitic protozoan, Lecudina tuzetae (Gregarine, Apicomplexa). (United States)

    Kuriyama, Ryoko; Besse, Colette; Gèze, Marc; Omoto, Charlotte K; Schrével, Joseph


    Lecudina tuzetae is a parasitic protozoan (Gregarine, Apicomplexa) living in the intestine of a marine polychaete annelid, Nereis diversicolor. Using electron and fluorescence microscopy, we have characterized the dynamic changes in microtubule organization during the sexual phase of the life cycle. The gametocyst excreted from the host worm into seawater consists of two (one male and one female) gamonts in which cortical microtubule arrays are discernible. Each gamont undergoes multiple nuclear divisions without cytokinesis, resulting in the formation of large multinucleate haploid cells. After cellularization, approximately 1000 individual gametes are produced from each gamont within 24 h. Female gametes are spherical and contain interphase cytoplasmic microtubule arrays emanating from a gamma-tubulin-containing site. In male gametes, both interphase microtubules and a flagellum with "6 + 0" axonemal microtubules extend from the same microtubule-organizing site. At the beginning of spore formation, each zygote secretes a wall to form a sporocyst. Following meiotic and mitotic divisions, each sporocyst gives rise to eight haploid cells that ultimately differentiate into sporozoites. The ovoid shaped sporocyst is asymmetric and forms at least two distinctive microtubule arrays: spindle microtubules and microtubule bundles originating from the protruding apical end corresponding to the dehiscence pole of the sporocyst. Because antibodies raised against mammalian centrosome components, such as gamma-tubulin, pericentrin, Cep135, and mitosis-specific phosphoproteins, react strongly with the microtubule-nucleating sites of Lecudina, this protozoan is likely to share common centrosomal antigens with higher eukaryotes. PMID:16240430

  1. Insights into bilaterian evolution from three spiralian genomes

    Energy Technology Data Exchange (ETDEWEB)

    Simakov, Oleg; Marletaz, Ferdinand; Cho, Sung-Jin; Edsinger-Gonzales, Eric; Havlak, Paul; Hellsten, Uffe; Kuo, Dian-Han; Larsson, Tomas; Lv, Jie; Arendt, Detlev; Savage, Robert; Osoegawa, Kazutoyo; de Jong, Pieter; Grimwood, Jane; Chapman, Jarrod A.; Shapiro, Harris; Otillar, Robert P.; Terry, Astrid Y.; Boore, Jeffrey L.; Grigoriev, Igor V.; Lindberg, David R.; Seaver, Elaine C.; Weisblat, David A.; Putnam, Nicholas H.; Rokhsar, Daniel S.; Aerts, Andrea


    Current genomic perspectives on animal diversity neglect two prominent phyla, the molluscs and annelids, that together account for nearly one-third of known marine species and are important both ecologically and as experimental systems in classical embryology1, 2, 3. Here we describe the draft genomes of the owl limpet (Lottia gigantea), a marine polychaete (Capitella teleta) and a freshwater leech (Helobdella robusta), and compare them with other animal genomes to investigate the origin and diversification of bilaterians from a genomic perspective. We find that the genome organization, gene structure and functional content of these species are more similar to those of some invertebrate deuterostome genomes (for example, amphioxus and sea urchin) than those of other protostomes that have been sequenced to date (flies, nematodes and flatworms). The conservation of these genomic features enables us to expand the inventory of genes present in the last common bilaterian ancestor, establish the tripartite diversification of bilaterians using multiple genomic characteristics and identify ancient conserved long- and short-range genetic linkages across metazoans. Superimposed on this broadly conserved pan-bilaterian background we find examples of lineage-specific genome evolution, including varying rates of rearrangement, intron gain and loss, expansions and contractions of gene families, and the evolution of clade-specific genes that produce the unique content of each genome.

  2. Fossil worm burrows reveal very early terrestrial animal activity and shed light on trophic resources after the end-cretaceous mass extinction.

    Directory of Open Access Journals (Sweden)

    Karen Chin

    Full Text Available The widespread mass extinctions at the end of the Cretaceous caused world-wide disruption of ecosystems, and faunal responses to the one-two punch of severe environmental perturbation and ecosystem collapse are still unclear. Here we report the discovery of in situ terrestrial fossil burrows from just above the impact-defined Cretaceous-Paleogene (K/Pg boundary in southwestern North Dakota. The crisscrossing networks of horizontal burrows occur at the interface of a lignitic coal and silty sandstone, and reveal intense faunal activity within centimeters of the boundary clay. Estimated rates of sedimentation and coal formation suggest that the burrows were made less than ten thousand years after the end-Cretaceous impact. The burrow characteristics are most consistent with burrows of extant earthworms. Moreover, the burrowing and detritivorous habits of these annelids fit models that predict the trophic and sheltering lifestyles of terrestrial animals that survived the K/Pg extinction event. In turn, such detritus-eaters would have played a critical role in supporting secondary consumers. Thus, some of the carnivorous vertebrates that radiated after the K/Pg extinction may owe their evolutionary success to thriving populations of earthworms.

  3. Community characteristics and secondary production of macrozoobenthos in intertidal zone of the Yellow River Estuary%黄河入海口潮间带大型底栖动物群落组成及次级生产力

    Institute of Scientific and Technical Information of China (English)

    王志忠; 张金路; 陈述江; 杜兴华; 段登选; 刘艳春; 蒋万钊; 赵磊


    为了解黄河入海口潮间带大型底栖生物现状,于2008年和2009年黄河枯水期的5月和丰水期的8月分别对黄河入海口5条潮间带断面大型底栖动物进行了采样调查.结果表明,采集到大型底栖动物65种,其中软体动物26种、甲壳动物22种、多毛类12种、腔肠动物2种、腕足动物、棘皮动物和鱼类各1种.软体动物和甲壳动物是构成潮间带底栖动物的主要类群.黄河入海口潮间带大型底栖动物平均栖息密度为(929.60±356.53)/m2,平均生物量(湿重)为(169.92±7.31)g/m2.在栖息密度组成中,软体动物占绝对优势,其次甲壳动物和多毛类,其他类群较低.Shannon-Weiner多样性指数为1.44±0.44,Margalef物种丰富度指数1.57±0.15,Pielou均匀度指数0.42±0.11.年平均去灰干重(13.96±0.61)g(AFDW)/m2,年次级生产力(11.26±0.62)g( AFDW)/( m2·a),P/B值平均(0.89±0.11)/a,表明黄河入海口潮间带个体较大、生活史较长的大型底栖动物种类所占比例较高.%In order to understand the present status of macrozoobenthic fauna in the intertidal zone of Yellow River Estuary, four surveys were made at 5 sections of the zone in May and Aug. of 2008 and 2009. A total of 65 maerozoobenthos species were recorded, including 26 species Mollusc, 22 species Crustacea, 12 species annelid polychaete, 2 species Coelenterate, 1 species Brachiopoda, 1 species Echinoderm and 1 species fish. The dominant species were Mollusc and Crustacea. The inhabit density and biomass (fresh weight) of maerozoobenthos were (929. 60 ± 356. 53 )/m2 and (169. 92 ±7.31) g/m2 respectively. The dominant inhabit density species were as follows: Mollusc > Crustacea and annelid polychaete > the other kinds. The mean Shannon-Weiner index was 1.44 ±0.44 when the mean Margalef species richness index and the mean Pielou evenness index were 1. 57 ±0. 15 and 0.42 ±0. 11 respectively. The mean ash free dry mass per year was (13. 96 ±0. 61 )g( AFDW)/m2 with the

  4. Effects of natural and human-induced hypoxia on coastal benthos

    Directory of Open Access Journals (Sweden)

    L. A. Levin


    Full Text Available Coastal hypoxia (<1.42 ml L−1; 62.5 μM; 2 mg L−1, approx. 30% oxygen saturation occurs seasonally in many estuaries, fjords, and along open coasts subject to upwelling or excessive riverine nutrient input, and permanently in some isolated seas and marine basins. Underlying causes of hypoxia include enhanced nutrient input from natural causes (upwelling or anthropogenic origin (eutrophication and reduction of mixing by limited circulation or enhanced stratification; combined these lead to higher surface water production, microbial respiration and eventual oxygen depletion. Advective inputs of low-oxygen waters may initiate or expand hypoxic conditions. Responses of estuarine, enclosed sea, and open shelf benthos to hypoxia depend on the duration, predictability, and intensity of oxygen depletion and on whether H2S is formed. Under suboxic conditions, large mats of filamentous sulfide oxidizing bacteria cover the seabed and consume sulfide, thereby providing a detoxified microhabitat for eukaryotic benthic communities. Calcareous foraminiferans and nematodes are particularly tolerant of low oxygen concentrations and may attain high densities and dominance, often in association with microbial mats. When oxygen is sufficient to support metazoans, small, soft-bodied invertebrates (typically annelids, often with short generation times and elaborate branchial structures, predominate. Large taxa are more sensitive than small taxa to hypoxia. Crustaceans and echinoderms are typically more sensitive to hypoxia, with lower oxygen thresholds, than annelids, sipunculans, molluscs and cnidarians. Mobile fish and shellfish will migrate away from low-oxygen areas. Within a species, early life stages may be more subject to oxygen stress than older life stages.

    Hypoxia alters both the structure and function of benthic communities, but effects may differ with regional hypoxia history. Human-caused hypoxia is generally

  5. The inter-annual variation trend of intertidal biodiversity in August in the ecology-monitoring area of Changli in Hebei%河北昌黎生态监控区8月潮间带生物多样性年际变化趋势

    Institute of Scientific and Technical Information of China (English)

    张月明; 梁晓林; 赵志楠; 韩晓庆; 金照光; 高伟明


    依据国家海洋环境监测中心2009~2013年测得的数据和资料,对河北昌黎生态监控区潮间带生物的种类组成、栖息密度、生物量、优势种以及多样性指数进行统计运算,分析该监控区5年时间尺度的潮间带生物多样性变化趋势。结果表明:监控区共鉴定出潮间带生物5门,包括节肢动物、环节动物、软体动物、棘皮动物和脊索动物,共17科,26种,类型较少,年际种数呈逐年下降趋势;栖息密度与生物量较低,保持低潮带>中潮带>高潮带的特征;优势种群变化显著,节肢动物、环节动物和软体动物交替出现,优势种数逐年减少,优势度上升,对其他物种抑制作用增强;均匀度指数(J)呈微上升趋势,变化范围为0.64~0.81,状况良好,物种多样性指数(H′)和丰富度指数(dMa)水平较低,分别为0.81~3.23和0.48~3.96,生物多样性水平呈下降态势。%According to the monitoring data and information obtained from National Marine Environmental Monitoring Center, the species composition, density, biomass, dominant species andthe trend of biodiversity variation in the ecology-monitoring area of Changli in Hebei Province from 2009 to 2013 were analyzed. The results showed that 5 phylum including arthropods, annelid, mollusks, echinodermata and chordata, totally 17 family and 26 species were identified. The types and number of species were declined annually. The density and biomass were consistent with the characteristics of low tidal zone>medium tidal zone>high tidal zone. The dominant species were changed significantly, by which arthropods, annelid and mollusks appearing alternately. As the decreasing of the number of dominant species, the dominance index went up which suppressed the other species. The Shannon-Wiener’s index(H’), Margalef’s richness index (dMa) were low, and their variation ranges were 0.81~3.23 and 0.48~3.96, respectively. The variation range of Pielou’s evenness index (J) was

  6. Glacier Ecosystems of Himalaya (United States)

    Kohshima, S.; Yoshimura, Y.; Takeuchi, N.; Segawa, T.; Uetake, J.


    Biological activity on glaciers has been believed to be extremely limited. However, we found various biotic communities specialized to the glacier environment in various part of the world, such as Himalaya, Patagonia and Alaska. Some of these glacier hosted biotic communities including various cold-tolerant insects, annelids and copepods that were living in the glacier by feeding on algae and bacteria growing in the snow and ice. Thus, the glaciers are simple and relatively closed ecosystems sustained by the primary production in the snow and ice. In this presentation, we will briefly introduce glacier ecosystems in Himalaya; ecology and behavior of glacier animals, altitudinal zonation of snow algal communities, and the structure of their habitats in the glacier. Since the microorganisms growing on the glacier surface are stored in the glacial strata every year, ice-core samples contain many layers with these microorganisms. We showed that the snow algae in the ice-core are useful for ice core dating and could be new environmental signals for the studies on past environment using ice cores. These microorganisms in the ice core will be important especially in the studies of ice core from the glaciers of warmer regions, in which chemical and isotopic contents are often heavily disturbed by melt water percolation. Blooms of algae and bacteria on the glacier can reduce the surface albedo and significantly affect the glacier melting. For example, the surface albedo of some Himalayan glaciers was significantly reduced by a large amount of dark-colored biogenic material (cryoconite) derived from snow algae and bacteria. It increased the melting rates of the surfaces by as much as three-fold. Thus, it was suggested that the microbial activity on the glacier could affect the mass balance and fluctuation of the glaciers.

  7. Biodiversity of Macrofauna Associated with Sponges across Ecological Gradients in the Central Red Sea

    KAUST Repository

    Kandler, Nora


    Between 33 and 91 percent of marine species are currently undescribed, with the majority occurring in tropical and offshore environments. Sponges act as important microhabitats and promote biodiversity by harboring a wide variety of macrofauna and microbiota, but little is known about the relationships between the sponges and their symbionts. This study uses DNA barcoding to examine the macrofaunal communities associated with sponges of the central Saudi Arabian Red Sea, a drastically understudied ecosystem with high biodiversity and endemism. In total, 185 epifaunal and infaunal operational taxonomic units (OTUs) were distinguished from the 1399 successfully-sequenced macrofauna individuals from 129 sponges representing seven sponge species, one of which (Stylissa carteri) was intensively studied. A significant difference was found in the macrofaunal community composition of Stylissa carteri along a cross-shelf gradient using relative OTU abundance (Bray-Curtis diversity index). The abundance of S. carteri also follows a cross-shelf gradient, increasing with proximity to shore. The difference in macrofaunal communities of several species of sponges at one location was found to be significant as well, using OTU presence (binary Jaccard diversity index). Four of the seven sponge species collected were dominated by a single annelid OTU, each unique to one sponge species. A fifth was dominated by four arthropod OTUs, all species-specific as well. Region-based diversity differences may be attributed to environmental factors such as reef morphology, water flow, and sedimentation, whereas species-based differences may be caused by sponge morphology, microbial abundances, and chemical defenses. As climate change and ocean acidification continue to modify coral reef ecosystems, understanding the ecology of sponges and their role as microhabitats may become more important. This thesis also includes a supplemental document in the form of a spreadsheet showing the number of

  8. Molecular cloning and characterization of taurocyamine kinase from Clonorchis sinensis: a candidate chemotherapeutic target.

    Directory of Open Access Journals (Sweden)

    Jing-Ying Xiao


    Full Text Available BACKGROUND: Adult Clonorchis sinensis lives in the bile duct and causes endemic clonorchiasis in East Asian countries. Phosphagen kinases (PK constitute a highly conserved family of enzymes, which play a role in ATP buffering in cells, and are potential targets for chemotherapeutic agents, since variants of PK are found only in invertebrate animals, including helminthic parasites. This work is conducted to characterize a PK from C. sinensis and to address further investigation for future drug development. METHODOLOGY/PRINCIPAL FINDINGS: [corrected] A cDNA clone encoding a putative polypeptide of 717 amino acids was retrieved from a C. sinensis transcriptome. This polypeptide was homologous to taurocyamine kinase (TK of the invertebrate animals and consisted of two contiguous domains. C. sinensis TK (CsTK gene was reported and found consist of 13 exons intercalated with 12 introns. This suggested an evolutionary pathway originating from an arginine kinase gene group, and distinguished annelid TK from the general CK phylogenetic group. CsTK was found not to have a homologous counterpart in sequences analysis of its mammalian hosts from public databases. Individual domains of CsTK, as well as the whole two-domain enzyme, showed enzymatic activity and specificity toward taurocyamine substrate. Of the CsTK residues, R58, I60 and Y84 of domain 1, and H60, I63 and Y87 of domain 2 were found to participate in binding taurocyamine. CsTK expression was distributed in locomotive and reproductive organs of adult C. sinensis. Developmentally, CsTK was stably expressed in both the adult and metacercariae stages. Recombinant CsTK protein was found to have low sensitivity and specificity toward C. sinensis and platyhelminth-infected human sera on ELISA. CONCLUSION: CsTK is a promising anti-C. sinensis drug target since the enzyme is found only in the C. sinensis and has a substrate specificity for taurocyamine, which is different from its mammalian counterpart

  9. A Tale of Two Drug Targets: The Evolutionary History of BACE1 and BACE2

    Directory of Open Access Journals (Sweden)

    Christopher eSouthan


    Full Text Available The beta amyloid (APP cleaving enzyme (BACE1 has been a drug target for Alzheimer's Disease (AD since 1999 with lead inhibitors now entering clinical trials. In 2011, the paralogue, BACE2, became a new target for type II diabetes (T2DM having been identified as a TMEM27 secretase regulating pancreatic β cell function. However, the normal roles of both enzymes are unclear. This study outlines their evolutionary history and new opportunities for functional genomics. We identified 30 homologues (UrBACEs in basal phyla including Placozoans, Cnidarians, Choanoflagellates, Porifera, Echinoderms, Annelids, Mollusks and Ascidians (but not Ecdysozoans. UrBACEs are predominantly single copy, show 35% to 45% protein sequence identity with mammalian BACE1, are approximately 100 residues longer than cathepsin paralogues with an aspartyl protease domain flanked by a signal peptide and a C-terminal transmembrane domain. While multiple paralogues in Trichoplax and Monosiga pre-date the nervous system, duplication of the UrBACE in fish gave rise to BACE1 and BACE2 in the vertebrate lineage. The latter evolved more rapidly as the former maintained the emergent neuronal role. In mammals, Ka/Ks for BACE2 is higher than BACE1 but low ratios for both suggest purifying selection. The 5’ exons show higher Ka/Ks than the catalytic section. Model organism genomes show the absence of certain BACE human substrates when the UrBACE is present. Experiments could thus reveal undiscovered substrates and roles. The human protease double-target status means that evolutionary trajectories and functional shifts associated with different substrates will have implications for the development of clinical candidates for both AD and T2DM. A rational basis for inhibition specificity ratios and assessing target-related side effects will be facilitated by a more complete picture of BACE1 and BACE2 functions informed by their evolutionary context.

  10. [Demography and the phenomenon of intraspecific competition of Gymnophallidae Morozov, 1955 in the second intermediate hosts (Trematoda, Digenea)]. (United States)

    Bartoli, P


    In Gymnophallidae life-cycle, the primary host is very often a Lamelli-branch, rarely a Prosobranch; the second intermediate host is usually a Pelecypod, rarely a Prosobranch or an Annelid. The first host is generally sedentary; consequently, cercariae are not widely spread. The second intermediate host cannot explore all the environment. These characters are not in favour of the parasite. Adaptation of Gymnophallid cycle consists in a very large cercarial productivity (several millions for only one first host). The recruiting modalities of Gymnophallid larvae by the second intermediate host are not always the same. Two different mechanisms have been discovered. The first one consists of a limited recruiting. The number of metacercariae is not always growing up during the host-life. This number depends on the volume of microhabitat. The top number is reached when microhabitat is saturated. The second one consists of a illimited recruiting. The number of parasites increases during all the second host life. This peculiarity is possible because the metacercariae are permanently carried out of the microhabitat where they had settled. Parasites are indeed progressively surrounded by pallial proliferations and become enclosed inside pockets of host tissues. Thus, microhabitat is always free of parasites and infection can go on. There must be a correlation between the mechanism of the recruitment of Gymnophallid larvae by a given second host and the characteristics of the environment where the life cycle unfolds. In confined environment (almost closed lagoons, brackish ponds) the number of cercariae is very large and the recruitment observed is limited. Then, the host-life is preserved. In wide open stations, where hydrodynamism is important, cercariae are scattered. The recruitment observed is illimited. This peculiarity is probably an adaptative factor permitting concentration of larvae in the second intermediate host. PMID:7258994