WorldWideScience

Sample records for ascidian ciona edwardsii

  1. Adverse Effect of Antifouling Compounds on the Reproductive Mechanisms of the Ascidian Ciona intestinalis

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    Alessandra Gallo

    2013-09-01

    Full Text Available Fertilization and embryo development that occur in sea water are sensitive to xenobiotics from anthropogenic sources. In this work, we evaluated the influence of two antifouling biocides, tributyltin (TBT and diuron, on the reproductive mechanisms of the marine invertebrate Ciona intestinalis. By using electrophysiological techniques, we examined the impact of these compounds on the electrical properties of the mature oocytes and of events occurring at fertilization. With different toxicity assays, we studied the effect of the two biocides on the gametes by evaluating fertilization rate and embryo development. Results show that sodium (Na+ currents were significantly reduced by either of the two biocides, whereas conductance was significantly increased. The fertilization current frequency and amplitude, fertilization rate and larval development were affected only by TBT. This study suggests that: (i the two biocides affect either the electrical properties of the oocyte plasma membrane and the reproductive success representing a risk factor for the survival of the species exposed to environmental pollution; (ii the ascidian Ciona intestinalis may represent a good model organism to test toxicity of marine pollutants. Possible mechanisms of action of the two biocides are discussed.

  2. Mind the gap – context dependency in invasive species impacts: a case study of the ascidian Ciona robusta

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    Tamara B. Robinson

    2017-01-01

    Full Text Available In the face of increasing invasions and limited resources, appropriate management of invasive species requires prioritisation of species for management action. This process often relies on knowledge of species specific impacts. However, as studies explicitly measuring impact of marine alien species are rare, prioritisation of management actions is often based on studies from outside the geographic area of interest. Further, few impact studies account for context dependency (e.g. seasonal variability or distinct environmental regimes, raising the question of how transferrable knowledge about the impact of a species is between invaded ranges. This study addressed this question by using the widespread invasive solitary ascidian Ciona robusta as a case study for assessing impacts across two invaded regions: South Africa and California, USA. We replicated a previously conducted experiment from California that showed that C. robusta depresses local species richness in San Francisco Bay. Our South African experiment showed no effect of C. robusta on species richness, the Shannon-Weiner diversity index or community composition, despite experiments being carried out over two years and at two depths. While these results may reflect strong density dependency in the impact of C. robusta, they serve to highlight context dependency in invasive species impacts. This suggests that until studies of impact in marine systems become common place, context dependency should be explicitly addressed as a source of uncertainty during the prioritisation of species for management action.

  3. Trunk lateral cells are neural crest-like cells in the ascidian Ciona intestinalis: insights into the ancestry and evolution of the neural crest.

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    Jeffery, William R; Chiba, Takuto; Krajka, Florian Razy; Deyts, Carole; Satoh, Nori; Joly, Jean-Stéphane

    2008-12-01

    Neural crest-like cells (NCLC) that express the HNK-1 antigen and form body pigment cells were previously identified in diverse ascidian species. Here we investigate the embryonic origin, migratory activity, and neural crest related gene expression patterns of NCLC in the ascidian Ciona intestinalis. HNK-1 expression first appeared at about the time of larval hatching in dorsal cells of the posterior trunk. In swimming tadpoles, HNK-1 positive cells began to migrate, and after metamorphosis they were localized in the oral and atrial siphons, branchial gill slits, endostyle, and gut. Cleavage arrest experiments showed that NCLC are derived from the A7.6 cells, the precursors of trunk lateral cells (TLC), one of the three types of migratory mesenchymal cells in ascidian embryos. In cleavage arrested embryos, HNK-1 positive TLC were present on the lateral margins of the neural plate and later became localized adjacent to the posterior sensory vesicle, a staging zone for their migration after larval hatching. The Ciona orthologues of seven of sixteen genes that function in the vertebrate neural crest gene regulatory network are expressed in the A7.6/TLC lineage. The vertebrate counterparts of these genes function downstream of neural plate border specification in the regulatory network leading to neural crest development. The results suggest that NCLC and neural crest cells may be homologous cell types originating in the common ancestor of tunicates and vertebrates and support the possibility that a putative regulatory network governing NCLC development was co-opted to produce neural crest cells during vertebrate evolution.

  4. The central nervous system of the ascidian larva: mitotic history of cells forming the neural tube in late embryonic Ciona intestinalis.

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    Cole, Alison G; Meinertzhagen, Ian A

    2004-07-15

    Ascidian larvae develop after an invariant pattern of embryonic cleavage. Fewer than 400 cells constitute the larval central nervous system (CNS), which forms without either extensive migration or cell death. We catalogue the mitotic history of these cells in Ciona intestinalis, using confocal microscopy of whole-mount embryos at stages from neurulation until hatching. The positions of cells contributing to the CNS were reconstructed from confocal image stacks of embryonic nuclei, and maps of successive stages were used to chart the mitotic descent, thereby creating a cell lineage for each cell. The entire CNS is formed from 10th- to 14th-generation cells. Although minor differences exist in cell position, lineage is invariant in cells derived from A-line blastomeres, which form the caudal nerve cord and visceral ganglion. We document the lineage of five pairs of presumed motor neurons within the visceral ganglion: one pair arises from A/A 10.57, and four from progeny of A/A 9.30. The remaining cells of the visceral ganglion are in their 13th and 14th generations at hatching, with most mitotic activity ceasing around 85% of embryonic development. Of the approximately 330 larval cells previously reported in the CNS of Ciona, we document the lineage of 226 that derive predominantly from A-line blastomeres.

  5. The diatom-derived aldehyde decadienal affects life cycle transition in the ascidian Ciona intestinalis through nitric oxide/ERK signalling.

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    Castellano, Immacolata; Ercolesi, Elena; Romano, Giovanna; Ianora, Adrianna; Palumbo, Anna

    2015-03-01

    Polyunsaturated aldehydes (PUAs) are fatty-acid-derived metabolites produced by some microalgae, including different diatom species. PUAs are mainly produced as a wound-activated defence mechanism against microalgal predators or released from senescent cells at the end of a bloom. PUAs, including 2,4-trans-decadienal (DD), induce deleterious effects on embryonic and larval development of several planktonic and benthic organisms. Here, we report on the effects of DD on larval development and metamorphosis of the ascidian Ciona intestinalis. Ciona larval development is regulated by the cross-talking of different molecular events, including nitric oxide (NO) production, ERK activation and caspase 3-dependent apoptosis. We report that treatment with DD at the competence larval stage results in a delay in metamorphosis. DD affects redox balance by reducing total glutathione and NO levels. By biochemical and quantitative gene expression analysis, we identify the NO-signalling network affected by DD, including the upregulation of ERK phosphatase mkp1 and consequent reduction of ERK phosphorylation, with final changes in the expression of downstream ERK target genes. Overall, these results give new insights into the molecular pathways induced in marine organisms after exposure to PUAs during larval development, demonstrating that this aldehyde affects key checkpoints of larval transition from the vegetative to the reproductive life stage.

  6. Molecular and functional characterization of cionin receptors in the ascidian, Ciona intestinalis: the evolutionary origin of the vertebrate cholecystokinin/gastrin family.

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    Sekiguchi, Toshio; Ogasawara, Michio; Satake, Honoo

    2012-04-01

    Cholecystokinin (CCK) and gastrin are vertebrate brain-gut peptides featured by a sulfated tyrosine residue and a C-terminally amidated tetrapeptide consensus sequence. Cionin, identified in the ascidian, Ciona intestinalis, the closest species to vertebrates, harbors two sulfated tyrosines and the CCK/gastrin consensus tetrapeptide sequence. While a putative cionin receptor, cior, was cloned, the ligand-receptor relationship between cionin and CioR remains unidentified. Here, we identify two cionin receptors, CioR1 and CioR2, which are the aforementioned putative cionin receptor and its novel paralog respectively. Phylogenetic analysis revealed that CioRs are homologous to vertebrate CCK receptors (CCKRs) and diverged from a common ancestor in the Ciona-specific lineage. Cionin activates intracellular calcium mobilization in cultured cells expressing CioR1 or CioR2. Monosulfated and nonsulfated cionin exhibited less potent or no activity, indicating that CioRs possess pharmacological features similar to the vertebrate CCK-specific receptor CCK1R, rather than its subtype CCK2R, given that a sulfated tyrosine in CCK is required for binding to CCK1R, but not to CCK2R. Collectively, the present data reveal that CioRs share a common ancestor with vertebrate CCKRs and indicate that CCK and CCK1R form the ancestral ligand-receptor pair in the vertebrate CCK/gastrin system. Cionin is expressed in the neural complex, digestive organs, oral siphon and atrial siphons, whereas the expression of ciors was detected mainly in these tissues and the ovary. Furthermore, cioninergic neurons innervate both of the siphons. These results suggest that cionin is involved in the regulation of siphonal functions.

  7. Characterization and metal-induced gene transcription of two new copper zinc superoxide dismutases in the solitary ascidian Ciona intestinalis

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    Ferro, Diana [Department of Biology, University of Padova, Padova (Italy); Institute for Evolution and Biodiversity, Westfälische Wilhelms-Universität, Münster (Germany); Franchi, Nicola [Department of Biology, University of Padova, Padova (Italy); Department of Biological, Chemical, Pharmaceutical Science and Technology, University of Palermo, Palermo (Italy); Mangano, Valentina [Department of Biological, Chemical, Pharmaceutical Science and Technology, University of Palermo, Palermo (Italy); Bakiu, Rigers [Department of Crop Production, Agricultural University of Tirana, Tirana (Albania); Cammarata, Matteo; Parrinello, Nicolò [Department of Biological, Chemical, Pharmaceutical Science and Technology, University of Palermo, Palermo (Italy); Santovito, Gianfranco, E-mail: gianfranco.santovito@unipd.it [Department of Biology, University of Padova, Padova (Italy); Ballarin, Loriano [Department of Biology, University of Padova, Padova (Italy)

    2013-09-15

    Highlights: •Ciona intestinalis express two copper-zinc superoxide dismutases (Cu,Zn SODs), one extracellular (Ci-SODa) and one intracellular isoform (Ci-SODb). •Promoters contain consensus sequences similar to mammalian MRE. •Metal exposure results in a significant increase of gene transcription: ci-soda is induced especially by copper and zinc, the increase of ci-sodb transcription is more evident after cadmium exposure. •Genes are mostly transcribed in circulating hemocytes and in ovarian follicular cells. -- Abstract: Antioxidant enzymes are known to protect living organisms against the oxidative stress risk, also induced by metals. In the present study, we describe the purification and molecular characterization of two Cu,Zn superoxide dismutases (SODs), referred to as Ci-SODa and Ci-SODb, from Ciona intestinalis, a basal chordate widely distributed in temperate shallow seawater. The putative amino acid sequences were compared with Cu,Zn SODs from other metazoans and phylogenetic analyses indicate that the two putative Ci-SODs are more related to invertebrate SODs than vertebrate ones. Both phylogenetic and preliminary homology modeling analyses suggest that Ci-SODa and Ci-SODb are extracellular and intracellular isoform, respectively. The mRNA of the two Cu,Zn SODs was localized in hemocytes and in ovarian follicular cells, as revealed by in situ hybridization. The time course of SOD mRNA levels in the presence of three different metals showed upregulation of ci-soda and inhibition of ci-sodb. Spectrophotometric analysis confirms the presence of SOD activity in Ciona tissues. Our in silico analyses of the ci-soda promoter region revealed putative consensus sequences similar to mammalian metal-responsive elements (MRE), suggesting that the transcription of these genes directly depends on metals. These data emphasize the importance of complex metal regulation of ci-soda and ci-sodb transcription, as components of an efficient detoxification pathway

  8. Reference gene selection for quantitative gene expression studies during biological invasions: A test on multiple genes and tissues in a model ascidian Ciona savignyi.

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    Huang, Xuena; Gao, Yangchun; Jiang, Bei; Zhou, Zunchun; Zhan, Aibin

    2016-01-15

    As invasive species have successfully colonized a wide range of dramatically different local environments, they offer a good opportunity to study interactions between species and rapidly changing environments. Gene expression represents one of the primary and crucial mechanisms for rapid adaptation to local environments. Here, we aim to select reference genes for quantitative gene expression analysis based on quantitative Real-Time PCR (qRT-PCR) for a model invasive ascidian, Ciona savignyi. We analyzed the stability of ten candidate reference genes in three tissues (siphon, pharynx and intestine) under two key environmental stresses (temperature and salinity) in the marine realm based on three programs (geNorm, NormFinder and delta Ct method). Our results demonstrated only minor difference for stability rankings among the three methods. The use of different single reference gene might influence the data interpretation, while multiple reference genes could minimize possible errors. Therefore, reference gene combinations were recommended for different tissues - the optimal reference gene combination for siphon was RPS15 and RPL17 under temperature stress, and RPL17, UBQ and TubA under salinity treatment; for pharynx, TubB, TubA and RPL17 were the most stable genes under temperature stress, while TubB, TubA and UBQ were the best under salinity stress; for intestine, UBQ, RPS15 and RPL17 were the most reliable reference genes under both treatments. Our results suggest that the necessity of selection and test of reference genes for different tissues under varying environmental stresses. The results obtained here are expected to reveal mechanisms of gene expression-mediated invasion success using C. savignyi as a model species.

  9. Mutation studies in ascidians: a review.

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    Crocetta, Fabio; Marino, Rita; Cirino, Paola; Macina, Alberto; Staiano, Leopoldo; Esposito, Rosaria; Pezzotti, Maria Rosa; Racioppi, Claudia; Toscano, Francesco; De Felice, Elena; Locascio, Annamaria; Ristoratore, Filomena; Spagnuolo, Antonietta; Zanetti, Laura; Branno, Margherita; Sordino, Paolo

    2015-01-01

    Historically, mutations have had a significant impact on the study of developmental processes and phenotypic evolution. Lesions in DNA are created by artificial methods or detected by natural genetic variation. Random mutations are then ascribed to genetic change by direct sequencing or positional cloning. Tunicate species of the ascidian genus Ciona represent nearly fully realized model systems in which gene function can be investigated in depth. Additionally, tunicates are valuable organisms for the study of naturally occurring mutations due to the capability to exploit genetic variation down to the molecular level. Here, we summarize the available information about how mutations are studied in ascidians with examples of insights that have resulted from these applications. We also describe notions and methodologies that might be useful for the implementation of easy and tight procedures for mutations studies in Ciona.

  10. Distribution of Centruroides edwardsii CENTRUROIDES EDWARDSII (GERVAIS, 1843 in the Aantioquia Province, Colombia

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    SEBASTIAN ESTRADA GÓMEZ

    2014-07-01

    Full Text Available  We report the distribution of the Centruroides edwardsii (Gervais, 1843 in the Antioquia province, and the urban area of the capital, Medellín, Colombia, based in the material examined in the collection of the Universidad de Antioquia Serpentarium (SUA. A sexual dimporphism were established in C. edwardsii when a multidimensional analysis and using for the statistical significance the ANOSIM model were performed founding higher measurments in males. An important colony of this scorpion is reported in the central and nor-oriental zone of Medellín, aspect that is very relevant since this scorpion is clinically importance. The species distribution rank is also expanded from the sea level, up to 2200 m. a. s. l. DISTRIBUCIÓN DE Ccentruroides edwardsii (GERVAIS, 1843 EN EL DEPARTAMENTO EN ANTIOQUIA, COLOMBIA. Se reporta la distribución de Centruroides edwardsii (Gervais, 1843 para el departamento de Antioquia, y el área urbana de su capital político-administrativa, la ciudad de Medellín, Colombia, con base a material depositado en la colección del Serpentario de la Universidad de Antioquia (SUA. Se estableció dimorfismo sexual en C. edwardsii, mediante análisis de escalamiento multidimensional y el modelo ANOSIM, encontrando que los machos son más grandes que las hembras. Se reporta para el área zona centro y nor-oriental de Medellín una importante colonia de este escorpión, hecho de gran relecvanciarelevancia debido a la importancia clínica de este escorpión. Se amplía además el rango de distribución desde el nivel del mar hasta los 2200 m.s.n.m.

  11. Inositol tri-phosphate inhuman and ascidian spermatozoa.

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    Tosti, E; Palumbo, A; Dale, B

    1993-05-01

    Using a specific protein binding assay we have shown that a spermatozoon of the ascidian Ciona intestinalis contains 1.58 +/- 0.74 x 10(-19) moles of inositol 1,4,5-tri-phosphate (InsP3), while a human spermatozoon contains 6.4 +/- 0.14 x 10(-19) moles. Induction of the acrosome reaction (AR) in both species, by exposure to the calcium ionophore A23187, does not significantly alter levels of InsP3, suggesting that phosphatidylinositol (PI) turnover is not necessary for the calcium ionophore induced AR. Furthermore, PI turnover in ascidian spermatozoa appears to be insensitive to lithium and phorbol ester. The high intracellular concentration of InsP3 in spermatozoa, corresponding to 50-200 microM, suggests it may play a role in egg activation.

  12. Effects of tributyltin chloride in ascidian embryos: modulation of kinase-mediated signalling pathways

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    F Damiani

    2009-03-01

    Full Text Available We studied the effects of various TBT concentrations by assaying the activity of ERK 1/2 (p44/42 and phospho-ERK1/2 (phospho-p44/42, proteins with a key role in ascidian development, and tyrosine kinase-dependent pathway. The effects of this xenobiotic and the role of some signalling mechanisms on ascidian embryos were examined by using Western immunoblotting. The tyrosine phosphorylation pattern in the ascidians Ciona intestinalis and Phallusia mammillata development was examined and different levels of protein phosphorylation were found as a response to TBT at μM range. To determine whether another key signalling pathway was activated, the effects of TBT on the phosphorylation state of a component of tyrosine kinase-mediated signal transduction MAPK, ERK 1/2 (p44/42 were evaluated. Embryos of Ciona intestinalis exposed to 0.1, 0.25 and 0.5 μM TBT showed a slight decrement in the level of phosphorylated ERK, while a remarkable decrement in level of phopshorylated ERK were observed at higher TBT concentrations (0.5 μM to 10 μM. These data indicated that exposures to TBT induced changes in the total pattern of phosphotyrosine and in the phosphorylation levels of ERK 1/2 but there were no changes on the overall level of total ERK in ascidian embryos.

  13. Identification of chondroitin/dermatan sulfotransferases in the protochordate, Ciona intestinalis.

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    Tetsukawa, Akira; Nakamura, Jun; Fujiwara, Shigeki

    2010-10-01

    Sulfated glycosaminoglycans are important components of connective tissues. The pattern of sulfation is important for their biological functions. Ascidians, the closest relatives of vertebrates, have a simple chordate body plan. In the present study, we identified an almost complete set of genes encoding proteins homologous to chondroitin/dermatan sulfotransferases in the genome of the ascidian Ciona intestinalis. We found eight genes encoding 4-O-sulfotransferases, eight genes encoding 6-O-sulfotransferases, and three genes encoding uronyl 2-O-sulfotransferases. The number of sulfotransferase genes was unexpectedly large, considering that ascidians do not have a well-developed endoskeleton. In addition, most of the genes within each sub-family seemed to have arisen by gene duplication events that occurred in the ascidian lineage after divergence from the main chordate lineage. This suggests that a unique pattern of sulfation independently developed during ascidian evolution. Some of the genes identified in the present study showed tissue-specific expression in the epidermis, notochord, muscle, and central nervous system. Region-specific expression in the epidermis was also observed. The present study provides useful information for further comparative and functional analyses of sulfotransferases and proteoglycans in chordate embryos.

  14. Genetic perspectives on the ascidian central nervous system

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    A Locascio

    2009-03-01

    Full Text Available In 2002, date of publication of the Ciona intestinalis genome, ascidians entered the post-genomic era. This tool had a fundamental role and has become the starting point for a series of new functional and genomic studies. Recently, great efforts have been done to characterize the genetic cascades of genes having a key role in early embryonic development and to draw the regulatory networks in which they are involved. In this review, we focused our attention on the last advances obtained in the attempt to clarify the complex molecular events governing ascidian central nervous system development with a special interest for anterior neural and sensory structures. We discussed the more recent theories on its early induction and late regionalization. In particular, we used some conserved genes fully or partially characterized as examples to compare ascidian and vertebrate central nervous system (CNS.By integrating the various results obtained with microarray, morpholino loss of function and promoter analyses, we showed that many progresses have been done to unravel the gene networks controlling early CNS induction and formation. Unfortunately, fewer advances have been done in the identification of the regulatory cascades controlling late CNS regionalization and sensory organs differentiation. Some results are discussed to point out the importance of fully characterizing also these specific regulatory cascades.

  15. Taxonomy Icon Data: Ciona intestinalis (Sea squirt) [Taxonomy Icon

    Lifescience Database Archive (English)

    Full Text Available ttp://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Ciona+intestinalis&t=L http://biosciencedbc.jp/taxonomy_icon.../icon.cgi?i=Ciona+intestinalis&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cg...i?i=Ciona+intestinalis&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Ciona+intestinalis&t=NS ... ...data Ciona_intestinalis_L.png Ciona_intestinalis_NL.png Ciona_intestinalis_S.png Ciona_intestinalis_NS.png h

  16. Diverse ETS transcription factors mediate FGF signaling in the Ciona anterior neural plate.

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    Gainous, T Blair; Wagner, Eileen; Levine, Michael

    2015-03-15

    The ascidian Ciona intestinalis is a marine invertebrate belonging to the sister group of the vertebrates, the tunicates. Its compact genome and simple, experimentally tractable embryos make Ciona well-suited for the study of cell-fate specification in chordates. Tunicate larvae possess a characteristic chordate body plan, and many developmental pathways are conserved between tunicates and vertebrates. Previous studies have shown that FGF signals are essential for neural induction and patterning at sequential steps of Ciona embryogenesis. Here we show that two different ETS family transcription factors, Ets1/2 and Elk1/3/4, have partially redundant activities in the anterior neural plate of gastrulating embryos. Whereas Ets1/2 promotes pigment cell formation in lateral lineages, both Ets1/2 and Elk1/3/4 are involved in the activation of Myt1L in medial lineages and the restriction of Six3/6 expression to the anterior-most regions of the neural tube. We also provide evidence that photoreceptor cells arise from posterior regions of the presumptive sensory vesicle, and do not depend on FGF signaling. Cells previously identified as photoreceptor progenitors instead form ependymal cells and neurons of the larval brain. Our results extend recent findings on FGF-dependent patterning of anterior-posterior compartments in the Ciona central nervous system.

  17. Natural variation of model mutant phenotypes in Ciona intestinalis.

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    Paolo Sordino

    Full Text Available BACKGROUND: The study of ascidians (Chordata, Tunicata has made a considerable contribution to our understanding of the origin and evolution of basal chordates. To provide further information to support forward genetics in Ciona intestinalis, we used a combination of natural variation and neutral population genetics as an approach for the systematic identification of new mutations. In addition to the significance of developmental variation for phenotype-driven studies, this approach can encompass important implications in evolutionary and population biology. METHODOLOGY/PRINCIPAL FINDINGS: Here, we report a preliminary survey for naturally occurring mutations in three geographically interconnected populations of C. intestinalis. The influence of historical, geographical and environmental factors on the distribution of abnormal phenotypes was assessed by means of 12 microsatellites. We identified 37 possible mutant loci with stereotyped defects in embryonic development that segregate in a way typical of recessive alleles. Local populations were found to differ in genetic organization and frequency distribution of phenotypic classes. CONCLUSIONS/SIGNIFICANCE: Natural genetic polymorphism of C. intestinalis constitutes a valuable source of phenotypes for studying embryonic development in ascidians. Correlating genetic structure and the occurrence of abnormal phenotypes is a crucial focus for understanding the selective forces that shape natural finite populations, and may provide insights of great importance into the evolutionary mechanisms that generate animal diversity.

  18. Inverse correlation of population similarity and introduction date for invasive ascidians.

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    Nathan Silva

    Full Text Available The genomes of many marine invertebrates, including the purple sea urchin and the solitary ascidians Ciona intestinalis and Ciona savignyi, show exceptionally high levels of heterozygosity, implying that these populations are highly polymorphic. Analysis of the C. savignyi genome found little evidence to support an elevated mutation rate, but rather points to a large population size contributing to the polymorphism level. In the present study, the relative genetic polymorphism levels in sampled populations of ten different ascidian species were determined using a similarity index generated by AFLP analysis. The goal was to determine the range of polymorphism within the populations of different species, and to uncover factors that may contribute to the high level of polymorphism. We observe that, surprisingly, the levels of polymorphism within these species show a negative correlation with the reported age of invasive populations, and that closely related species show substantially different levels of genetic polymorphism. These findings show exceptions to the assumptions that invasive species start with a low level of genetic polymorphism that increases over time and that closely related species have similar levels of genetic polymorphism.

  19. Characterization of a Novel Rhamnose-containing Acidic Glycosphingolipid from the Ascidian Halocynthia aurantium.

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    Kojima, Hisao; Shinohara, Ryota; Itonori, Saki; Ito, Masahiro

    2017-03-01

    Halocynthia aurantium, an edible ascidian species belonging to Urochordata, was subjected to structural characterization of acidic glycosphingolipids to investigate these molecules in ascidians: sulfatide from Ciona intestinalis and the glucuronic acid-containing acidic glycosphingolipid from H. roretzi. Acidic glycosphingolipids containing three or five sugars were isolated from soft parts of the ascidian H. aurantium by chloroform-methanol extraction, mild-alkaline hydrolysis, precipitation with cold acetone, and subsequent column chromatography using a DEAE-Sephadex A-25 column, a Florisil column, and an Iatrobead column. The structures of these glycosphingolipids were determined by methylation studies, sugar analysis, fatty acid analysis, sphingoid analysis, mass spectrometry, and proton nuclear magnetic resonance spectroscopy. A novel glucuronic acid-containing glycosphingolipid having a rhamnose residue was identified as Rhaα1-3GlcNAcβ1-3Galβ1-4(Fucα1-3)GlcAβ1-Cer (UGL-2). This novel structure is particularly unusual given that it contains both a rhamnose residue and a reducing terminal glucuronic acid residue within a single molecule. Rhamnose is a characteristic sugar, which is a component of cell wall pectin in plants and exopolysaccharides in bacteria. Ascidians acquired the cellulose synthase gene via lateral gene transfer, and therefore, it can be speculated that they also acquired the rhamnosyltransferase gene in the same manner. We also detected Galβ1-4(Fucα1-3)GlcAβ1-Cer (UGL-1), which was already identified in another ascidian, H. roretzi.

  20. Focusing on Ciona intestinalis (Tunicata innate immune system. Evolutionary implications

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    N Parrinello

    2009-03-01

    Full Text Available Phylogenetic analyses based on molecular data provide compelling evidence that ascidians are of critical importance for studying chordate immune system evolution. The Ciona intestinalis draft genome sequence allows searches for phylogenetic relationships, gene cloning and expression of immunorelevant molecules. Acidians lack of the pivotal components of the vertebrate recombinatory adaptive immunity, i.e., MHC, TCRs and dimeric immunoglobulins. However, bioinformatic sequence analyses recognized genic elements indicating the essential features of the Ig superfamily and ancestor proto-MHC genes, suggesting a primitive pre-duplication and pre-recombination status. C. intestinalis genes for individuality in the absence of MHC could encode diverse molecular markers, including a wide panel of complement factors that could be responsible for self-nonself discrimination. Genome analysis reveals a number of innate immunity vertebrate-like genes which encode Toll-like and virus receptors, complement pathways components and receptors, CD94/NK-receptor-like, lectins, TNF, IL1-R, collagens. However, pure homology seeking for vertebrate-specific immunorelevant molecules is of limited value, and functional screening methods may be a more promising approach for tracing the immune system evolution. C. intestinalis, which displays acute and chronic inflammatory reactions, is a model organism for studying innate immunity genes expression and functions.

  1. Ascidian gene-expression profiles

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    Jeffery, William R.

    2002-01-01

    With the advent of gene-expression profiling, a large number of genes can now be investigated simultaneously during critical stages of development. This approach will be particularly informative in studies of ascidians, basal chordates whose genomes and embryology are uniquely suited for mapping developmental gene networks.

  2. Further EST analysis of endocrine genes that are preferentially expressed in the neural complex of Ciona intestinalis: receptor and enzyme genes associated with endocrine system in the neural complex.

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    Sekiguchi, Toshio; Kawashima, Takeshi; Satou, Yutaka; Satoh, Nori

    2007-01-15

    Identification of orthologs of vertebrate neuropeptides and hypothalamic hormones in the neural complex of ascidians suggests integral roles of the ascidian neural complex in the endocrine system. In the present study, we investigated endocrine-related genes expressed in the neural complex of Ciona intestinalis. Comprehensive analyses of 3'-end sequences of the neural complex cDNAs placed 10,029 clones into 4051 independent clusters or genes, 1524 of them being expressed preferentially in this organ. Comparison of the 1524 genes with the human proteome databank demonstrated that 476 matched previously identified human proteins with distinct functions. Further analyses of sequence similarity of the 476 genes demonstrated that 21 genes are candidates for those involved in the endocrine system. Although we cannot detect hormone or peptide candidates, we found 21 genes such as receptors for peptide ligands, receptor-modulating proteins, and processing enzymes. We then characterized the Ciona prohormone convertase 2 (Ci-PC2) and carboxypeptidase E (Ci-CPE), which are associated with endoproteolytic processing of peptide hormone precursors. Furthermore, genes encoding these transcripts are expressed specifically in the neural complex of young adult ascidians. These data provide the molecular basis for further functional studies of the endocrine role of the neural complex of ascidians.

  3. 3D-printed microwell arrays for Ciona microinjection and timelapse imaging.

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    Clint Gregory

    Full Text Available Ascidians such as Ciona are close chordate relatives of the vertebrates with small, simple embryonic body plans and small, simple genomes. The tractable size of the embryo offers considerable advantages for in toto imaging and quantitative analysis of morphogenesis. For functional studies, Ciona eggs are considerably more challenging to microinject than the much larger eggs of other model organisms such as zebrafish and Xenopus. One of the key difficulties is in restraining the eggs so that the microinjection needle can be easily introduced and withdrawn. Here we develop and test a device to cast wells in agarose that are each sized to hold a single egg. This injection mold is fabricated by micro-resolution stereolithography with a grid of egg-sized posts that cast corresponding wells in agarose. This 3D printing technology allows the rapid and inexpensive testing of iteratively refined prototypes. In addition to their utility in microinjection, these grids of embryo-sized wells are also valuable for timelapse imaging of multiple embryos.

  4. Intraspecific Variation of Centruroides Edwardsii Venom from Two Regions of Colombia

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    Sebastián Estrada-Gómez

    2014-07-01

    Full Text Available We report the first description studies, partial characterization, and intraspecific difference of Centruroides edwardsii, Gervais 1843, venom. C. edwardsii from two Colombian regions (Antioquia and Tolima were evaluated. Both venoms showed hemolytic activity, possibly dependent of enzymatic active phospholipases, and neither coagulant nor proteolytic activities were observed. Venom electrophoretic profile showed significant differences between C. edwardsii venom from both regions. A high concentration of proteins with molecular masses between 31 kDa and 97.4 kDa, and an important concentration close or below 14.4 kDa were detected. RP-HPLC retention times between 38.2 min and 42.1 min, showed bands close to 14.4 kDa, which may correspond to phospholipases. RP-HPLC venom profile showed a well conserved region in both venoms between 7 and 17 min, after this, significant differences were detected. From Tolima region venom, 50 well-defined peaks were detected, while in the Antioquia region venom, 55 well-defined peaks were detected. Larvicidal activity was only detected in the C. edwardsii venom from Antioquia. No antimicrobial activity was observed using complete venom or RP-HPLC collected fractions of both venoms. Lethally activity (carried out on female albino swiss mice was detected at doses over 19.2 mg/kg of crude venom. Toxic effects included distress, excitability, eye irritation and secretions, hyperventilation, ataxia, paralysis, and salivation.

  5. Ultrastructural comparative analysis on the adhesive papillae of the swimming larvae of three ascidian species

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    G Dolcemascolo

    2009-03-01

    Full Text Available This paper presents a preliminary report on the papillae of the swimming larvae of three ascidian species: Ascidia malaca, Phallusia mammillata and Ciona intestinalis. The investigations, carried out at ultrastructural level and at confocal laser microscope, have evidenced, in the adhesive papillae of the three studied species, three different cell-types: axial columnar cells, collocytes, sensory cells respectively. The adhesive papillae of A. malaca and P. mammillata show central axial columnar cells with long microvilli emerging from the apical edge and extending throughout the hyaline cap. Collocytes are elongated secreting cells, lying in middle-lateral side. Sensory cells have a cilium at the apical side and an axon proceeding from the basal side. The adhesive papillae of C. intestinalis present some differences in the ultrastructure of the axial columnar cells, which bear a big digitiform protrusion, extending throughout the hyaline cap and a lot of microtubules along the cell axis. The investigations, carried out at confocal microscopy, have evidentiated a clear fluorescence in the papillae of the three studied species and a network of nervous fibers projecting from the papillar base up to cerebral vesicle of the cephalenteron. The characteristic of simple and coniforme type and the adhesive and sensorial functions of adhesive papillae of three ascidian species examined are confirmed.

  6. Ascidians (Tunicata) of the French Guiana Expedition.

    Science.gov (United States)

    Monniot, Françoise

    2016-05-24

    Ascidians were collected along the shore of Iles du Salut and deeper on the slope in a program of evaluation of the biodiversity in Guiana. Most of the samples belong to already known species from the Caribbean area and Brazilian coast. The colonial forms dominate. The 6 new species have been dredged deeper than 50m but not found by SCUBA divers. In spite of an intensive sampling, the ascidian diversity in Guiana is low with 36 species recorded. This is the result of the abundance of sediment suspended in the water and uniformly deposited on all substrates which affects filtration rate and limits the settling of the ascidian larvae.

  7. Functional Brachyury binding sites establish a temporal read-out of gene expression in the Ciona notochord.

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    Lavanya Katikala

    2013-10-01

    Full Text Available The appearance of the notochord represented a milestone in Deuterostome evolution. The notochord is necessary for the development of the chordate body plan and for the formation of the vertebral column and numerous organs. It is known that the transcription factor Brachyury is required for notochord formation in all chordates, and that it controls transcription of a large number of target genes. However, studies of the structure of the cis-regulatory modules (CRMs through which this control is exerted are complicated in vertebrates by the genomic complexity and the pan-mesodermal expression territory of Brachyury. We used the ascidian Ciona, in which the single-copy Brachyury is notochord-specific and CRMs are easily identifiable, to carry out a systematic characterization of Brachyury-downstream notochord CRMs. We found that Ciona Brachyury (Ci-Bra controls most of its targets directly, through non-palindromic binding sites that function either synergistically or individually to activate early- and middle-onset genes, respectively, while late-onset target CRMs are controlled indirectly, via transcriptional intermediaries. These results illustrate how a transcriptional regulator can efficiently shape a shallow gene regulatory network into a multi-tiered transcriptional output, and provide insights into the mechanisms that establish temporal read-outs of gene expression in a fast-developing chordate embryo.

  8. Revised lineage of larval photoreceptor cells in Ciona reveals archetypal collaboration between neural tube and neural crest in sensory organ formation.

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    Oonuma, Kouhei; Tanaka, Moeko; Nishitsuji, Koki; Kato, Yumiko; Shimai, Kotaro; Kusakabe, Takehiro G

    2016-12-01

    The Ciona intestinalis larva has two distinct photoreceptor organs, a conventional pigmented ocellus and a nonpigmented ocellus, that are asymmetrically situated in the brain. The ciliary photoreceptor cells of these ocelli resemble visual cells of the vertebrate retina. Precise elucidation of the lineage of the photoreceptor cells will be key to understanding the developmental mechanisms of these cells as well as the evolutionary relationships between the photoreceptor organs of ascidians and vertebrates. Photoreceptor cells of the pigmented ocellus have been thought to develop from anterior animal (a-lineage) blastomeres, whereas the developmental origin of the nonpigmented ocellus has not been determined. Here, we show that the photoreceptor cells of both ocelli develop from the right anterior vegetal hemisphere: those of the pigmented ocellus from the right A9.14 cell and those of the nonpigmented ocellus from the right A9.16 cell. The pigmented ocellus is formed by a combination of two lineages of cells with distinct embryonic origins: the photoreceptor cells originate from a medial portion of the A-lineage neural plate, while the pigment cell originates from the lateral edge of the a-lineage neural plate. In light of the recently proposed close evolutionary relationship between the ocellus pigment cell of ascidians and the cephalic neural crest of vertebrates, the ascidian ocellus may represent a prototypic contribution of the neural crest to a cranial sensory organ.

  9. Chondroitin 4-O-sulfotransferases are required for cell adhesion and morphogenesis in the Ciona intestinalis embryo.

    Science.gov (United States)

    Nakamura, Jun; Tetsukawa, Akira; Fujiwara, Shigeki

    2015-01-01

    Chondroitin sulfate (CS) is a carbohydrate component of proteoglycans. Several types of sulfotransferases determine the pattern of CS sulfation, and thus regulate the biological functions of proteoglycans. The protochordate ascidians are the closest relatives of vertebrates, but the functions of their sulfotransferases have not been investigated. Here, we show that two chondroitin 4-O-sulfotransferases (C4STs) play important roles in the embryonic morphogenesis of the ascidian Ciona intestinalis. Ci-C4ST-like1 is predominantly expressed in the epidermis and muscle. Epidermal and muscle cells became spherical upon the injection of a Ci-C4ST-like1-specific morpholino oligo (MO), thus suggesting weakened cell adhesion. Co-injection of a Ci-C4ST-like1-expressing transgene rescued the phenotype, suggesting that the effects of the MO were specific. Ci-C4ST-like3 was expressed in the central nervous system, muscle, and mesenchyme. A specific MO appeared to affect cell adhesion in the epidermis and muscle. Convergent extension movement of notochordal cells was also impaired. Forced expression of Ci-C4ST-like3 restored normal morphogenesis, suggesting that the effects of the MO were specific. The present study suggests that Ci-C4ST-like1 and Ci-C4ST-like3 are required for cell adhesion mainly in the epidermis and muscle.

  10. Distinctive expression patterns of Hedgehog pathway genes in the Ciona intestinalis larva: implications for a role of Hedgehog signaling in postembryonic development and chordate evolution.

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    Islam, A F M Tariqul; Moly, Pricila Khan; Miyamoto, Yuki; Kusakabe, Takehiro G

    2010-02-01

    Members of the Hedgehog (Hh) family are soluble ligands that orchestrate a wide spectrum of developmental processes ranging from left-right axis determination of the embryo to tissue patterning and organogenesis. Tunicates, including ascidians, are the closest relatives of vertebrates, and elucidation of Hh signaling in ascidians should provide an important clue towards better understanding the role of this pathway in development. In previous studies, expression patterns of genes encoding Hh and its downstream factor Gli have been examined up to the tailbud stage in the ascidian embryo, but their expression in the larva has not been reported. Here we show the spatial expression patterns of hedgehog (Ci-hh1, Ci-hh2), patched (Ci-ptc), smoothened (Ci-smo), and Gli (Ci-Gli) orthologs in larvae of the ascidian Ciona intestinalis. The expression patterns of Ci-hh2 and Ci-Gli dramatically change during the period between the late tailbud embryo and the swimming larva. At the larval stage, expression of Ci-Gli was found in a central part of the endoderm and in the visceral ganglion, while Ci-hh2 was expressed in two discrete endodermal regions, anteriorly and posteriorly adjacent to the cells expressing Gli. The expression patterns of these genes suggest that the Hh ligand controls postembryonic development of the endoderm and the central nervous system. Expression of a gene encoding Hh in the anterior and/or pharyngeal endoderm is probably an ancient chordate character; diversification of regulation and targets of the Hh signaling in this region may have played a major role in the evolution of chordate body structures.

  11. A multicassette Gateway vector set for high throughput and comparative analyses in ciona and vertebrate embryos.

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    Agnès Roure

    Full Text Available BACKGROUND: The past few years have seen a vast increase in the amount of genomic data available for a growing number of taxa, including sets of full length cDNA clones and cis-regulatory sequences. Large scale cross-species comparisons of protein function and cis-regulatory sequences may help to understand the emergence of specific traits during evolution. PRINCIPAL FINDINGS: To facilitate such comparisons, we developed a Gateway compatible vector set, which can be used to systematically dissect cis-regulatory sequences, and overexpress wild type or tagged proteins in a variety of chordate systems. It was developed and first characterised in the embryos of the ascidian Ciona intestinalis, in which large scale analyses are easier to perform than in vertebrates, owing to the very efficient embryo electroporation protocol available in this organism. Its use was then extended to fish embryos and cultured mammalian cells. CONCLUSION: This versatile vector set opens the way to the mid- to large-scale comparative analyses of protein function and cis-regulatory sequences across chordate evolution. A complete user manual is provided as supplemental material.

  12. Agonistic behaviour in juvenile southern rock lobster, Jasus edwardsii (Decapoda, Palinuridae: implications for developing aquaculture

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    Chris Carter

    2014-11-01

    Full Text Available The Southern rock lobster, Jasus edwardsii, is a temperate species of spiny lobster with established well managed fisheries in Australia and New Zealand. It has also been under consideration as a species with aquaculture potential. Agonistic behaviour has important consequences under aquaculture conditions that encompass direct effects, such as damage or death of protagonists, and indirect effects on growth that relate to resource access, principally food and refuge. This study aimed to identify and characterize behaviours and to make a preliminary investigation of their occurrence under tank culture. Juvenile Jasus edwardsii were examined in a flow-through seawater system using a remote video camera system. Twenty-nine behaviours were divided into three sub-groups: aggressive (11, avoidance (6 and others (12. Aggressive behaviours included attacks, pushing, lifting, clasping and carrying an opponent. Avoidance behaviours included moving away in a backwards-, forwards- or side-stepping motion as well as with more vigorous tail flips. These behaviours were components of twelve behavioural groups that described contact, attack and displacement between individuals. Activity was crepuscular with two clear peaks, one in the morning and the other in the evening. The occurrence of behavioural groups was not different between the morning and evening. The frequency of aggressive behaviours was not affected by changes made to stocking density or access to food. The implications of agonistic behaviours are discussed further in relation to developing aquaculture.

  13. Auto and cross regulatory elements control Onecut expression in the ascidian nervous system.

    Science.gov (United States)

    Pezzotti, Maria Rosa; Locascio, Annamaria; Racioppi, Claudia; Fucci, Laura; Branno, Margherita

    2014-06-15

    The expression pattern of Onecut genes in the central and peripheral nervous systems is highly conserved in invertebrates and vertebrates but the regulatory networks in which they are involved are still largely unknown. The presence of three gene copies in vertebrates has revealed the functional roles of the Onecut genes in liver, pancreas and some populations of motor neurons. Urochordates have only one Onecut gene and are the closest living relatives of vertebrates and thus represent a good model system to understand its regulatory network and involvement in nervous system formation. In order to define the Onecut genetic cascade, we extensively characterized the Onecut upstream cis-regulatory DNA in the ascidian Ciona intestinalis. Electroporation experiments using a 2.5kb genomic fragment and of a series of deletion constructs identified a small region of 262bp able to reproduce most of the Onecut expression profile during embryonic development. Further analyses, both bioinformatic and in vivo using transient transgenes, permitted the identification of transcription factors responsible for Onecut endogenous expression. We provide evidence that Neurogenin is a direct activator of Onecut and that an autoregulatory loop is responsible for the maintenance of its expression. Furthermore, for the first time we propose the existence of a direct connection among Neurogenin, Onecut and Rx transcription factors in photoreceptor cell formation.

  14. Ascidians from Rocas Atoll, northeast Brazil

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    Sandra Vieira Paiva

    2015-06-01

    Full Text Available Rocas Atoll is the only one of its kind in the South Atlantic—and the first Brazilian marine biological reserve. This is the first report about the ascidians from Rocas. A total of 12 species were found, 5 of them not hitherto described: Ascidia viridina sp. nov., Didemnum rochai sp. nov., Leptoclinides crocotulus sp. nov., Polysyncraton maurizeliae sp. nov., and Trididemnum rocasensis sp. nov.. One Caribbean species, Didemnum halimedae, was also discovered in the region for the first time. Further, this is the first record of Didemnum digestum in the Atlantic. The results indicate a high degree of endemism in the ascidian fauna from Rocas Atoll, where didemnids are presently the most important members.

  15. Amino Alcohols from the Ascidian Pseudodistoma sp.

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    Tae Hyung Won

    2014-06-01

    Full Text Available Seven new amino alcohol compounds, pseudoaminols A–G (1–7, were isolated from the ascidian Pseudodistoma sp. collected off the coast of Chuja-do, Korea. Structures of these new compounds were determined by analysis of the spectroscopic data and from chemical conversion. The presence of an N-carboxymethyl group in two of the new compounds (6 and 7 is unprecedented among amino alcohols. Several of these compounds exhibited moderate antimicrobial activity and cytotoxicity, as well as weak inhibitory activity toward Na+/K+-ATPase.

  16. Distinct Roles of Soluble and Transmembrane Adenylyl Cyclases in the Regulation of Flagellar Motility in Ciona Sperm

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    Kogiku Shiba

    2014-07-01

    Full Text Available Adenylyl cyclase (AC is a key enzyme that synthesizes cyclic AMP (cAMP at the onset of the signaling pathway to activate sperm motility. Here, we showed that both transmembrane AC (tmAC and soluble AC (sAC are distinctly involved in the regulation of sperm motility in the ascidian Ciona intestinalis. A tmAC inhibitor blocked both cAMP synthesis and the activation of sperm motility induced by the egg factor sperm activating and attracting factor (SAAF, as well as those induced by theophylline, an inhibitor of phoshodiesterase. It also significantly inhibited cAMP-dependent phosphorylation of a set of proteins at motility activation. On the other hand, a sAC inhibitor does not affect on SAAF-induced transient increase of cAMP, motility activation or protein phosphorylation, but it reduced swimming velocity to half in theophylline-induced sperm. A sAC inhibitor KH-7 induced circular swimming trajectory with smaller diameter and significantly suppressed chemotaxis of sperm to SAAF. These results suggest that tmAC is involved in the basic mechanism for motility activation through cAMP-dependent protein phosphorylation, whereas sAC plays distinct roles in increase of flagellar beat frequency and in the Ca2+-dependent chemotactic movement of sperm.

  17. Photosymbiotic ascidians in Singapore: turbid waters may reduce living space

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    Shih-Wei Su

    2013-05-01

    Full Text Available The photosymbiotic ascidian fauna at Changi Beach, Pulau Semakau, Sentosa and St. John’s Island, Singapore were surveyed. A total of five species, Diplosoma simile, Lissoclinum bistratum, L. punctatum, L. timorense and Trididemnum cyclops, were recorded, with L. timorense and T. cyclops being newly recorded in Singapore. However, no photosymbiotic species were found at Changi Beach probably due to the polluted waters in the region. Coastal development has caused Singapore waters to become turbid, leading to decrease in suitable habitats for photosymbiotic ascidians. Clean waters in Pulau Semakau probably provide a better environment for the growth of photosymbiotic ascidians and this area has a greater variety of these ascidians than the other areas in Singapore. Each of the five species has also been recorded in the Ryukyu Archipelago (Japan and three species (Diplosoma simile, Lissoclinum bistratum and Trididemnum cyclops have also been recorded in Taiwan.

  18. Haemolymph glucose concentrations of juvenile rock lobsters, Jasus edwardsii, feeding on different carbohydrate diets.

    Science.gov (United States)

    Radford, C A; Marsden, I D; Davison, W; Taylor, H H

    2005-02-01

    Postprandial changes in haemolymph glucose concentration ([Glc]H) were measured in 4-day-fasted juvenile intermoult spiny lobsters, Jasus edwardsii, provided with meals composed of glycogen, maltose, sucrose, glucose, or fructose in a gelatine base, or with gels of the algal glycans agar, alginate and carrageenan. Baseline [Glc]H was 0.61+/-0.02 mmol L(-1). After consumption of glycogen, maltose or sucrose, [Glc]H approximately doubled, peaked after 3 h and returned to baseline between 12 and 24 h. Glucose and fructose meals were followed by periods of sustained hyperglycaemia lasting more than 24 h (peaking at approximately 2.5 times baseline at 6 and 3 h respectively). Suggested explanations for augmented hyperglycaemic responses to glucose and fructose are: 1) these monosaccharides by-passed contact digestion and absorption in the R-cells of the digestive gland, directing them away from storage and toward transepithelial scavenging routes; or 2) glucose and fructose directly elicited release of crustacean hyperglycaemic hormone via a chemosensory reflex. Agar and alginate induced significant postprandial glycaemic responses, consistent with reports of carbohydrases in this species and indicating their potential for inclusion in artificial diets as both binders and energy sources. Carrageenan, a highly sulphated galactan, did not produce a glycaemic response. The measurement of glycaemic responses is a quick method of obtaining nutritional information on carbohydrates considered for inclusion in formulated diets prior to lengthy growth trials.

  19. The control of vascular resistance in the southern rock lobster, Jasus edwardsii (Decapoda: Palinuridae).

    Science.gov (United States)

    Wilkens, J L; Taylor, H H

    2003-07-01

    In Jasus edwardsii (Hutton) the vascular resistance of each of the seven major arterial systems leaving the heart was increased in response to several of the following neurotransmitters and neurohormones: acetylcholine, adrenalin, serotonin, dopamine, octopamine and peptides proctolin and FLRFamide-related peptide F(1). The resistance to flow through the infrabranchial sinus (IBS), part of the venous system, was also sensitive to these drugs. Unexpectedly, the responses of the IBS continued after removal of the gills. Differences in the profiles of responses of the arteries to individual hormones and in the magnitudes and the time courses of back pressure changes, eliminate a common downstream location such as the venous sinuses or gills, as the source of the arterial responses. Vasoactive drugs were effective when applied either via the lumen or, with longer delay, to the basal side of an artery via the IBS. It is concluded that the resistance of each of these sections of the vascular system is independently controllable by hormones.

  20. Investigation of genetic structure between deep and shallow populations of the southern Rock Lobster, Jasus edwardsii in Tasmania, Australia.

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    Erin M J Morgan

    Full Text Available The southern rock lobster, Jasus edwardsii, shows clear phenotypic differences between shallow water (red coloured and deeper water (pale coloured individuals. Translocations of individuals from deeper water to shallower waters are currently being trialled as a management strategy to facilitate a phenotypic change from lower value pale colouration, common in deeper waters, to the higher value red colouration found in shallow waters. Although panmixia across the J. edwardsii range has been long assumed, it is critical to assess the genetic variability of the species to ensure that the level of population connectivity is appropriately understood and translocations do not have unintended consequences. Eight microsatellite loci were used to investigate genetic differentiation between six sites (three shallow, three deep across southern Tasmania, Australia, and one from New Zealand. Based on analyses the assumption of panmixia was rejected, revealing small levels of genetic differentiation across southern Tasmania, significant levels of differentiation between Tasmania and New Zealand, and high levels of asymmetric gene flow in an easterly direction from Tasmania into New Zealand. These results suggest that translocation among Tasmanian populations are not likely to be problematic, however, a re-consideration of panmictic stock structure for this species is necessary.

  1. Investigation of genetic structure between deep and shallow populations of the southern Rock Lobster, Jasus edwardsii in Tasmania, Australia.

    Science.gov (United States)

    Morgan, Erin M J; Green, Bridget S; Murphy, Nicholas P; Strugnell, Jan M

    2013-01-01

    The southern rock lobster, Jasus edwardsii, shows clear phenotypic differences between shallow water (red coloured) and deeper water (pale coloured) individuals. Translocations of individuals from deeper water to shallower waters are currently being trialled as a management strategy to facilitate a phenotypic change from lower value pale colouration, common in deeper waters, to the higher value red colouration found in shallow waters. Although panmixia across the J. edwardsii range has been long assumed, it is critical to assess the genetic variability of the species to ensure that the level of population connectivity is appropriately understood and translocations do not have unintended consequences. Eight microsatellite loci were used to investigate genetic differentiation between six sites (three shallow, three deep) across southern Tasmania, Australia, and one from New Zealand. Based on analyses the assumption of panmixia was rejected, revealing small levels of genetic differentiation across southern Tasmania, significant levels of differentiation between Tasmania and New Zealand, and high levels of asymmetric gene flow in an easterly direction from Tasmania into New Zealand. These results suggest that translocation among Tasmanian populations are not likely to be problematic, however, a re-consideration of panmictic stock structure for this species is necessary.

  2. The ascidian pigmented sensory organs: structures and developmental programs.

    Science.gov (United States)

    Esposito, R; Racioppi, C; Pezzotti, M R; Branno, M; Locascio, A; Ristoratore, F; Spagnuolo, A

    2015-01-01

    The recent advances on ascidian pigment sensory organ development and function represent a fascinating platform to get insight on the basic programs of chordate eye formation. This review aims to summarize current knowledge, at the structural and molecular levels, on the two main building blocks of ascidian light sensory organ, i.e. pigment cells and photoreceptor cells. The unique features of these structures (e.g., simplicity and well characterized cell lineage) are indeed making it possible to dissect the developmental programs at single cell resolution and will soon provide a panel of molecular tools to be exploited for a deep developmental and comparative-evolutionary analysis.

  3. New Bioactive Alkyl Sulfates from Mediterranean Tunicates

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    Marialuisa Menna

    2012-10-01

    Full Text Available Chemical investigation of two species of marine ascidians, Aplidium elegans and Ciona edwardsii, collected in Mediterranean area, led to isolation of a series of alkyl sulfates (compounds 1–5 including three new molecules 1–3. Structures of the new metabolites have been elucidated by spectroscopic analysis. Based on previously reported cytotoxic activity of these type of molecules, compounds 1–3 have been tested for their effects on the growth of two cell lines, J774A.1 (BALB/c murine macrophages and C6 (rat glioma in vitro. Compounds 1 and 2 induced selective concentration-dependent mortality on J774A.1 cells.

  4. Latitudinal patterns in the life-history traits of three isolated Atlantic populations of the deep-water shrimp Plesionika edwardsii (Decapoda, Pandalidae)

    Science.gov (United States)

    González, José A.; Pajuelo, José G.; Triay-Portella, Raül; Ruiz-Díaz, Raquel; Delgado, João; Góis, Ana R.; Martins, Albertino

    2016-11-01

    Patterns in the life-history traits of the pandalid shrimp Plesionika edwardsii are studied for the first time in three isolated Atlantic populations (Madeira, Canaries and Cape Verde Islands) to gain an understanding of their latitudinal variations. The maximum carapace size of the populations studied, as well as the maximum weight, showed clear latitudinal patterns. The patterns observed may be a consequence of the temperature experienced by shrimps during development, 1.37 ° C higher in the Canaries and 5.96 ° C higher in the Cape Verde Islands than in Madeira. These temperature differences among populations may have induced phenotypic plasticity because the observed final body size decreased as the temperature increased. A latitudinal north-south pattern was also observed in the maximum size of ovigerous females, with larger sizes found in the Madeira area and lower sizes observed in the Cape Verde Islands. A similar pattern was observed in the brood size and maximum egg size. Females of P. edwardsii produced smaller eggs in the Cape Verde Islands than did those at the higher latitude in Madeira. P. edwardsii was larger at sexual maturity in Madeira than in the Cape Verde Islands. The relative size at sexual maturity is not affected by latitude or environmental factors and is the same in the three areas studied, varying slightly between 0.568 and 0.585. P. edwardsii had a long reproductive season with ovigerous females observed all year round, although latitudinal variations were observed. Seasonally, there were more ovigerous females in spring and summer in Madeira and from winter to summer in the Cape Verde Islands. P. edwardsii showed a latitudinal pattern in size, with asymptotic size and growth rate showing a latitudinal compensation gradient as a result of an increased growth performance in the Madeira population compared to that of the Cape Verde Islands.

  5. Valosin-containing protein/p97 interacts with sperm-activating and sperm-attracting factor (SAAF) in the ascidian egg and modulates sperm-attracting activity.

    Science.gov (United States)

    Kondoh, Eri; Konno, Aru; Inaba, Kazuo; Oishi, Tohru; Murata, Michio; Yoshida, Manabu

    2008-10-01

    Sperm chemotaxis toward an egg is observed in many animals, and the control of sperm-attracting activity is thought to play an important role in ensuring fertilization. However, the mechanism underlying the release of a sperm attractant from an egg is still obscure. In this study, we examined the systems involved in the release of sperm-activating and sperm-attracting factor (SAAF), which is the sperm attractant of the ascidian Ciona intestinalis. Here, we show that the egg acquires sperm-attracting activity after germinal vesicle breakdown. Further, since the cytoplasmic extracts of immature oocytes exhibit no sperm-attracting activity, the SAAF in oocytes may be activated after germinal vesicle breakdown. We found 13 SAAF-binding proteins in an egg plasma membrane extract and identified five proteins by proteomic analysis: valosin-containing protein (VCP)/p97, proteasome alpha 2 subunit, MGC97756 protein, proteasome subunit Y, and beta-tubulin. In particular, the interaction between VCP/p97 and SAAF was confirmed by a pull-down assay. VCP/p97 is initially localized in the germinal vesicle, and during oocyte maturation, it shifts to the endoplasmic reticulum in the cortical regions. Thus, VCP/p97 is a potential modulator of SAAF release from the egg.

  6. Refining the Ciona intestinalis model of central nervous system regeneration.

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    Carl Dahlberg

    Full Text Available BACKGROUND: New, practical models of central nervous system regeneration are required and should provide molecular tools and resources. We focus here on the tunicate Ciona intestinalis, which has the capacity to regenerate nerves and a complete adult central nervous system, a capacity unusual in the chordate phylum. We investigated the timing and sequence of events during nervous system regeneration in this organism. METHODOLOGY/PRINCIPAL FINDINGS: We developed techniques for reproducible ablations and for imaging live cellular events in tissue explants. Based on live observations of more than 100 regenerating animals, we subdivided the regeneration process into four stages. Regeneration was functional, as shown by the sequential recovery of reflexes that established new criteria for defining regeneration rates. We used transgenic animals and labeled nucleotide analogs to describe in detail the early cellular events at the tip of the regenerating nerves and the first appearance of the new adult ganglion anlage. CONCLUSIONS/SIGNIFICANCE: The rate of regeneration was found to be negatively correlated with adult size. New neural structures were derived from the anterior and posterior nerve endings. A blastemal structure was implicated in the formation of new neural cells. This work demonstrates that Ciona intestinalis is as a useful system for studies on regeneration of the brain, brain-associated organs and nerves.

  7. Geographic ranges of ascidians from Antarctica and the southeastern Pacific

    Institute of Scientific and Technical Information of China (English)

    Dirk Schories; Karen Sanamyan; Nadja Sanamyan; Mara Jos Daz; Ignacio Garrido; Thomas Heran; Jorge Holtheuer; Gesche Kohlberg

    2015-01-01

    Historical and novel data on the geographic and bathymetric distribution of ascidians from Antarctic, Magellan and Chilean waters are compiled, and an inventory of taxa comprising 162 species reported over a 150 year period from the Antarctic region South Polar Province (SPP) compiled. The ascidian fauna from the South Shetland Islands (SSI) is compared with that of the Magellan region, Patagonia and the Chilean coast. We collected 46 ascidian species along the Chilean coast, and during four expeditions to King George Island (SSI) by SCUBA between 2003–2012. About 15% of King George Island (SSI) species are observed to occur also in shallow waters of southern Chile (SCL). Few species known from warm temperate southeastern Pacific (Northern Chile, NCL) waters are absent from the Chilean part of the Magellan Province (SCL). With most data contributed from the Chilean coast coming from the SCL, and with limited sampling having been undertaken at depths exceeding 100 m in the NCL, apparent differences in species richness along the Chilean coast could be attributabed to differential sampling effort. We detail 12 species from our Antarctic and Chilean collections in detail, including one, Diplosoma listerianum, not previously reported from Chilean waters, and the genus Botryllus, previously known from them on the basis of a single record.

  8. Metabolic characteristics of muscles in the spiny lobster, Jasus edwardsii, and responses to emersion during simulated live transport.

    Science.gov (United States)

    Speed, S R; Baldwin, J; Wong, R J; Wells, R M

    2001-03-01

    The metabolic characteristics of five muscle groups in the spiny lobster Jasus edwardsii were examined in order to compare their anaerobic and oxidative capacities. Enzyme activities of phosphorylase, phosphofructokinase, pyruvate kinase, and lactate dehydrogenase were highest in abdominal muscles supporting anaerobic burst activity. Hexokinase, citrate synthase, and HOAD activities in the leg and antennal muscles indicated higher aerobic potential. Arginine kinase activities were high in all muscle groups indicating that muscle phosphagens are an important energy reserve. Arginine phosphate concentrations in 4th periopod and abdominal flexor muscle from lobsters sampled in the field were higher than any values from captive animals, and approximately five times those for ATP. Muscle lactates were high in captive animals. Responses to emersion during simulated live transport appear to exploit the capacity for functional anaerobiosis and further differentiated the muscle groups. Abdominal muscles were especially sensitive and after 24 h showed significant increases in lactate, glucose, ADP, and AMP. ATP levels appeared to be maintained by muscle phosphagens and raised doubts about the efficacy of the adenylate energy charge in evaluating the emersion response. Haemolymph glucose, lactic acid, and ammonia peaked after 24 h emersion and were largely restored following re-immersion. We propose that arginine phosphate concentrations in the 4th periopod are an appropriate index of metabolic stress, and could lead to improved commercial handling protocols.

  9. Evolution and development of brain sensory organs in molgulid ascidians.

    Science.gov (United States)

    Jeffery, William R

    2004-01-01

    The ascidian tadpole larva has two brain sensory organs containing melanocytes: the otolith, a gravity receptor, and the ocellus, part of a photoreceptor. One or both of these sensory organs are absent in molgulid ascidians. We show here that developmental changes leading to the loss of sensory pigment cells occur by different mechanisms in closely related molgulid species. Sensory pigment cells are formed through a bilateral determination pathway in which two or more precursor cells are specified as an equivalence group on each side of the embryo. The precursor cells subsequently converge at the midline after neurulation and undergo cell interactions that decide the fates of the otolith and ocellus. Molgula occidentalis and M. oculata, which exhibit a tadpole larva with an otolith but lacking an ocellus, have conserved the bilateral pigment cell determination pathway. Programmed cell death (PCD) is superimposed on this pathway late in development to eliminate the ocellus precursor and supernumerary pigment cells, which do not differentiate into either an otolith or ocellus. In contrast to molgulids with tadpole larvae, no pigment cell precursors are specified on either side of the M. occulta embryo, which forms a tailless (anural) larva lacking both sensory organs, suggesting that the bilateral pigment cell determination pathway has been lost. The bilateral pigment cell determination pathway and superimposed PCD can be restored in hybrids obtained by fertilizing M. occulta eggs with M. oculata sperm, indicating control by a zygotic process. We conclude that PCD plays an important role in the evolution and development of brain sensory organs in molgulid ascidians.

  10. Exploiting the extraordinary genetic polymorphism of ciona for developmental genetics with whole genome sequencing.

    Science.gov (United States)

    Abdul-Wajid, Sarah; Veeman, Michael T; Chiba, Shota; Turner, Thomas L; Smith, William C

    2014-05-01

    Studies in tunicates such as Ciona have revealed new insights into the evolutionary origins of chordate development. Ciona populations are characterized by high levels of natural genetic variation, between 1 and 5%. This variation has provided abundant material for forward genetic studies. In the current study, we make use of deep sequencing and homozygosity mapping to map spontaneous mutations in outbred populations. With this method we have mapped two spontaneous developmental mutants. In Ciona intestinalis we mapped a short-tail mutation with strong phenotypic similarity to a previously identified mutant in the related species Ciona savignyi. Our bioinformatic approach mapped the mutation to a narrow interval containing a single mutated gene, α-laminin3,4,5, which is the gene previously implicated in C. savignyi. In addition, we mapped a novel genetic mutation disrupting neural tube closure in C. savignyi to a T-type Ca(2+) channel gene. The high efficiency and unprecedented mapping resolution of our study is a powerful advantage for developmental genetics in Ciona, and may find application in other outbred species.

  11. Accelerated exchange of exon segments in Viperid three-finger toxin genes (Sistrurus catenatus edwardsii; Desert Massasauga

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    Mackessy Stephen P

    2008-07-01

    Full Text Available Abstract Background Snake venoms consist primarily of proteins and peptides showing a myriad of potent biological activities which have been shaped by both adaptive and neutral selective forces. Venom proteins are encoded by multigene families that have evolved through a process of gene duplication followed by accelerated evolution in the protein coding region. Results Here we report five gene structures of three-finger toxins from a viperid snake, Sistrurus catenatus edwardsii. These toxin genes are structured similarly to elapid and hydrophiid three-finger toxin genes, with two introns and three exons. Both introns and exons show distinct patterns of segmentation, and the insertion/deletion of segments may define their evolutionary history. The segments in introns, when present, are highly similar to their corresponding segments in other members of the gene family. In contrast, some segments in the exons show high similarity, while others are often distinctly different among corresponding regions of the isoforms. Conclusion Ordered, conserved exon structure strongly suggests that segments in corresponding regions in exons have been exchanged with distinctly different ones during the evolution of these genes. Such a "switching" of segments in exons may result in drastically altering the molecular surface topology and charge, and hence the molecular targets of these three-finger toxins. Thus the phenomenon of accelerated segment switch in exons to alter targeting (ASSET may play an important role in the evolution of three-finger toxins, resulting in a family of toxins with a highly conserved structural fold but widely varying biological activities.

  12. Ecology of ascidians in the macrofouling community of New Mangalore Port

    Digital Repository Service at National Institute of Oceanography (India)

    Venkat, K.; Anil, A.C.; Khandeparker, D.C.; Mokashe, S.S.

    was not observed during monsoon season (June-September). At this locality salinity does not drop substantially during monsoon months and hence the absence of ascidians during monsoon cannot be attributed to salinity stress. The only striking change...

  13. Photosymbiotic ascidians in Singapore: turbid waters may reduce living space

    Science.gov (United States)

    Su, Shih-Wei; Hirose, Euichi; Chen, Serina Lee Siew; Mok, Michael Hin-Kiu

    2013-01-01

    Abstract The photosymbiotic ascidian fauna at Changi Beach, Pulau Semakau, Sentosa and St. John’s Island, Singapore were surveyed. A total of five species, Diplosoma simile, Lissoclinum bistratum, Lissoclinum punctatum, Lissoclinum timorense and Trididemnum cyclops, were recorded, with Lissoclinum timorense and Trididemnum cyclops being newly recorded in Singapore. However, no photosymbiotic species were found at Changi Beach probably due to the polluted waters in the region. Coastal development has caused Singapore waters to become turbid, leading to decrease in suitable habitats for photosymbiotic ascidians. Clean waters in Pulau Semakau probably provide a better environment for the growth of photosymbiotic ascidians and this area has a greater variety of these ascidians than the other areas in Singapore. Each of the five species has also been recorded in the Ryukyu Archipelago (Japan) and three species (Diplosoma simile, Lissoclinum bistratum and Trididemnum cyclops) have also been recorded in Taiwan. PMID:23794913

  14. The diatom-derived aldehyde decadienal affects life cycle transition in the ascidian Ciona intestinalis through nitric oxide/ERK signalling

    OpenAIRE

    Castellano, Immacolata; Ercolesi, Elena; Romano, Giovanna; Ianora, Adrianna; Palumbo, Anna

    2015-01-01

    Polyunsaturated aldehydes (PUAs) are fatty-acid-derived metabolites produced by some microalgae, including different diatom species. PUAs are mainly produced as a wound-activated defence mechanism against microalgal predators or released from senescent cells at the end of a bloom. PUAs, including 2,4-trans-decadienal (DD), induce deleterious effects on embryonic and larval development of several planktonic and benthic organisms. Here, we report on the effects of DD on larval development and m...

  15. ANP (Atrial Natriuretic Peptide presence in the heart of a tunicate, Ciona intestinalis.

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    Aldo Gerbino

    2010-06-01

    Full Text Available Atrial natriuretic peptide was found in the heart of vertebrates, we studied the ANP presence in the heart of Ciona intestinalis. This is animal is very important because of the its evolutionary position between invertebrates and vertebrates. ANP presence was only revealed in myoepithelial cells of the myocardium. Results suggest the hypothesis that ANP is present not only in the vertebrates but also in the invertebrates and in Ciona heart ANP might play a similar role like in the heart of vertebrates.

  16. The challenges of trafficking hydrolysis prone metals and ascidians as an archetype.

    Science.gov (United States)

    Gaffney, Jean P; Valentine, Ann M

    2011-06-14

    Some of the metal ions that are required, exploited, or simply managed in biological systems are susceptible to hydrolysis and to hydrolytic precipitation in the aqueous, aerobic environment of much of biology. Organisms have evolved exquisite mechanisms for handling these metal ions, offering striking examples of biological control over inorganic coordination chemistry. This year marks the one hundredth anniversary of the discovery of remarkably high vanadium concentrations in the blood cells of the ascidian. In the ensuing years, these marine invertebrates were established as masters of the biological chemistry of very hydrolysis-prone metals, with various ascidian species accumulating high concentrations of iron, vanadium, and titanium, among others. These three metals have very different histories of biological relevance, and many questions remain about how, and ultimately why, these organisms sequester them. This Perspective addresses the aqueous coordination chemistry that organisms like ascidians must control if they are to manipulate hydrolysis-prone metal ions, and describes some of the ascidian biomolecules that have been implicated in this phenomenon. The recently available genome sequence for one ascidian species offers a glimpse into its metal-management arsenal. It offers the opportunity to map the relatively well-studied paradigm of iron management onto the genome of an organism that is intermediate in evolution between invertebrates and vertebrates. The ascidians have much to teach us about how to manage metals like iron, titanium, and vanadium and how that ability evolved.

  17. Antibacterial modified diketopiperazines from two ascidians of the genus Didemnum

    Energy Technology Data Exchange (ETDEWEB)

    Kossuga, Miriam H.; Lira, Simone P.; McHugh, Shayna; Torres, Yohandra R.; Berlinck, Roberto G.S. [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Inst. de Quimica; Lima, Bruna A.; Goncalves, Reginaldo [Universidade Estadual de Campinas, Piracicaba, SP (Brazil). Faculdade de Odontologia. Dept. de Diagnostico Oral; Veloso, Katyuscya; Ferreira, Antonio G. [Universidade Federal de Sao Carlos, SP (Brazil). Dept. de Quimica; Rocha, Rosana M. [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Centro Politecnico. Setor de Ciencias Biologicas. Dept. de Zoologia

    2009-07-01

    The chemical investigation of the crude extract of an ascidian of the genus Didemnum led to the isolation of the modified diketopiperazine rodriguesines A (1) and (2) as a mixture of homologues, which could be identified by analysis of spectroscopic data including MS/MS experiments. The investigation of a second Didemnum sp. led to the isolation of N-acetyl-rodriguesine A (3) and N-acetyl-rodriguesine B (4). The absolute configuration of compounds 1 and 2 could be established by hydrolysis and Marfey's analysis and comparison with literature data reported for compound 3, previously obtained as a synthetic product. The mixture of 1 and 2 displayed moderate antibiotic activity against a clinical isolate of Streptococcus mutans and against S. mutans UA159 and Staphylococcus aureus ATCC6538. (author)

  18. SNPs and Hox gene mapping in Ciona intestinalis

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    Biffali Elio

    2008-01-01

    Full Text Available Abstract Background The tunicate Ciona intestinalis (Enterogona, Ascidiacea, a major model system for evolutionary and developmental genetics of chordates, harbours two cryptic species. To assess the degree of intra- and inter-specific genetic variability, we report the identification and analysis of C. intestinalis SNP (Single Nucleotide Polymorphism markers. A SNP subset was used to determine the genetic distance between Hox-5 and -10 genes. Results DNA fragments were amplified from 12 regions of C. intestinalis sp. A. In total, 128 SNPs and 32 one bp indels have been identified within 8 Kb DNA. SNPs in coding regions cause 4 synonymous and 12 non-synonymous substitutions. The highest SNP frequency was detected in the Hox5 and Hox10 intragenic regions. In C. intestinalis, these two genes have lost their archetypal topology within the cluster, such that Hox10 is located between Hox4 and Hox5. A subset of the above primers was used to perform successful amplification in C. intestinalis sp. B. In this cryptic species, 62 SNPs were identified within 3614 bp: 41 in non-coding and 21 in coding regions. The genetic distance of the Hox-5 and -10 loci, computed combining a classical backcross approach with the application of SNP markers, was found to be 8.4 cM (Haldane's function. Based on the physical distance, 1 cM corresponds to 39.5 Kb. Linkage disequilibrium between the aforementioned loci was calculated in the backcross generation. Conclusion SNPs here described allow analysis and comparisons within and between C. intestinalis cryptic species. We provide the first reliable computation of genetic distance in this important model chordate. This latter result represents an important platform for future studies on Hox genes showing deviations from the archetypal topology.

  19. The gut of geographically disparate Ciona intestinalis harbors a core microbiota.

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    Larry J Dishaw

    Full Text Available It is now widely understood that all animals engage in complex interactions with bacteria (or microbes throughout their various life stages. This ancient exchange can involve cooperation and has resulted in a wide range of evolved host-microbial interdependencies, including those observed in the gut. Ciona intestinalis, a filter-feeding basal chordate and classic developmental model that can be experimentally manipulated, is being employed to help define these relationships. Ciona larvae are first exposed internally to microbes upon the initiation of feeding in metamorphosed individuals; however, whether or not these microbes subsequently colonize the gut and whether or not Ciona forms relationships with specific bacteria in the gut remains unknown. In this report, we show that the Ciona gut not only is colonized by a complex community of bacteria, but also that samples from three geographically isolated populations reveal striking similarity in abundant operational taxonomic units (OTUs consistent with the selection of a core community by the gut ecosystem.

  20. Ascidian recruitment patterns on an artificial reef in Eilat (Red Sea).

    Science.gov (United States)

    Shenkar, Noa; Zeldman, Yael; Loya, Yossi

    2008-01-01

    Although ascidians are conspicuous members of the fouling community not much is known regarding their recruitment patterns in coral reefs. A 1-year study was carried out along the Red Sea coast of Israel to examine the effects of season and spatial distribution on ascidian recruitment to artificial marine structures. In general, autumn and spring were characterized by higher coverage with a significantly higher percentage of cover of Didemnum granulatum in autumn and higher numbers of Herdmania momus in spring. These species contributed the most to similarity between treatments consequently setting the pattern for each group (colonial and solitary). Halocynthia spinosa had significantly higher numbers during winter and Phallusia nigra was absent in spring and winter. H. momus showed a preference for horizontal surfaces. P. nigra and Ascidia cannelata showed a preference for floating units. It is concluded that the ascidian recruitment patterns are species-specific and vary between seasons, orientation and position on the substrata and in the water column.

  1. Gut-spilling in chordates: evisceration in the tropical ascidian Polycarpa mytiligera.

    Science.gov (United States)

    Shenkar, Noa; Gordon, Tal

    2015-04-16

    The ejection of internal organs, i.e., evisceration, is a well-known phenomenon in sea-cucumbers. We report the ability of a member of the Chordate phyla, the tropical ascidian Polycarpa mytiligera, to eviscerate and regenerate its gut within 12 days, and to rebuild its branchial sac within 19 days. Evisceration occurred within 4-43 seconds of gentle mechanical pressure exerted on the tunic in 47% of the tested P. mytiligera. Individuals were able to discard up to 3/4 of their digestive tract via the incurrent siphon by rupture of the branchial sac in this area. Although chemical analysis revealed no significant levels of toxic compounds, the eviscerated guts were unpalatable to the triggerfish and pufferfish on which they were tested, suggesting evisceration as a defense mechanism. Given the close affinity of ascidians to vertebrates, the regeneration pathway of the viscera and branchial sac of ascidians suggests its potential beneficial application in soft tissue regeneration research.

  2. Sexual and asexual reproduction in the colonial ascidian Botryllus schlosseri.

    Science.gov (United States)

    Gasparini, Fabio; Manni, Lucia; Cima, Francesca; Zaniolo, Giovanna; Burighel, Paolo; Caicci, Federico; Franchi, Nicola; Schiavon, Filippo; Rigon, Francesca; Campagna, Davide; Ballarin, Loriano

    2015-01-01

    The colonial tunicate Botryllus schlosseri is a widespread filter-feeding ascidian that lives in shallow waters and is easily reared in aquaria. Its peculiar blastogenetic cycle, characterized by the presence of three blastogenetic generations (filtering adults, buds, and budlets) and by recurrent generation changes, has resulted in over 60 years of studies aimed at understanding how sexual and asexual reproduction are coordinated and regulated in the colony. The possibility of using different methodological approaches, from classical genetics to cell transplantation, contributed to the development of this species as a valuable model organism for the study of a variety of biological processes. Here, we review the main studies detailing rearing, staging methods, reproduction and colony growth of this species, emphasizing the asymmetry in sexual and asexual reproduction potential, sexual reproduction in the field and the laboratory, and self- and cross-fertilization. These data, opportunely matched with recent tanscriptomic and genomic outcomes, can give a valuable help to the elucidation of some important steps in chordate evolution.

  3. Ascidians as excellent chordate models for studying the development of the nervous system during embryogenesis and metamorphosis.

    Science.gov (United States)

    Sasakura, Yasunori; Mita, Kaoru; Ogura, Yosuke; Horie, Takeo

    2012-04-01

    The swimming larvae of the chordate ascidians possess a dorsal hollowed central nervous system (CNS), which is homologous to that of vertebrates. Despite the homology, the ascidian CNS consists of a countable number of cells. The simple nervous system of ascidians provides an excellent experimental system to study the developmental mechanisms of the chordate nervous system. The neural fate of the cells consisting of the ascidian CNS is determined in both autonomous and non-autonomous fashion during the cleavage stage. The ascidian neural plate performs the morphogenetic movement of neural tube closure that resembles that in vertebrate neural tube formation. Following neurulation, the CNS is separated into five distinct regions, whose homology with the regions of vertebrate CNS has been discussed. Following their larval stage, ascidians undergo a metamorphosis and become sessile adults. The metamorphosis is completed quickly, and therefore the metamorphosis of ascidians is a good experimental system to observe the reorganization of the CNS during metamorphosis. A recent study has shown that the major parts of the larval CNS remain after the metamorphosis to form the adult CNS. In contrast to such a conserved manner of CNS reorganization, most larval neurons disappear during metamorphosis. The larval glial cells in the CNS are the major source for the formation of the adult CNS, and some of the glial cells produce adult neurons.

  4. Immunobiology of compound ascidians, with particular reference to Botryllus schlosseri: state of art

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    L Ballarin

    2008-05-01

    Full Text Available The phylogenetic position of invertebrate chordates closely related to vertebrates explains the increasing interest towards tunicate immunobiology. Most of the tunicates are ascidians which, like all other invertebrates, rely only on innate immunity for their defense. Compound ascidians differ from solitary species for the presence of colony specificity, i.e. the ability for intraspecific non-self recognition. The immunobiology of compound ascidians has been particularly studied in Botryllus schlosseri, which is an emerging model organism for this kind of studies. In B. schlosseri and related species, immunocytes are represented by phagocytes and cytotoxic morula cells, the former able to ingest foreign cell and particles, the latter representing the effectors of the inflammatory reaction which follows the contact between genetically incompatible colonies. Activated phagocytes release lectins with opsonic activity and are involved in the clearance of apoptotic cells during the colonial generational change. Morula cells recognize the presence of foreign molecules as well as allogeneic soluble factors diffusing from an alien colony and as a consequence they: i release cytokines in the medium which have chemotactic activity and activate phagocytes; ii degranulate and release phenoloxidase which induces necrotic cell death by oxidative stress. A better knowledge of Botryllus genome will allow a deeper insight into open problems in immunobiology of compound ascidians.

  5. Muscle differentiation in a colonial ascidian: organisation, gene expression and evolutionary considerations

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    Burighel Paolo

    2009-09-01

    Full Text Available Abstract Background Ascidians are tunicates, the taxon recently proposed as sister group to the vertebrates. They possess a chordate-like swimming larva, which metamorphoses into a sessile adult. Several ascidian species form colonies of clonal individuals by asexual reproduction. During their life cycle, ascidians present three muscle types: striated in larval tail, striated in the heart, and unstriated in the adult body-wall. Results In the colonial ascidian Botryllus schlosseri, we investigated organisation, differentiation and gene expression of muscle beginning from early buds to adults and during zooid regression. We characterised transcripts for troponin T (BsTnT-c, adult muscle-type (BsMA2 and cytoplasmic-type (BsCA1 actins, followed by in situ hybridisation (ISH on sections to establish the spatio-temporal expression of BsTnT-c and BsMA2 during asexual reproduction and in the larva. Moreover, we characterised actin genomic sequences, which by comparison with other metazoans revealed conserved intron patterns. Conclusion Integration of data from ISH, phalloidin staining and TEM allowed us to follow the phases of differentiation of the three muscle kinds, which differ in expression pattern of the two transcripts. Moreover, phylogenetic analyses provided evidence for the close relationship between tunicate and vertebrate muscle genes. The characteristics and plasticity of muscles in tunicates are discussed.

  6. Modiolarca lateralis (Pteryomorphia: Mytilidae: bivalve associated to six species of ascidians from Bocas del Toro, Panama

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    Juan I Cañete

    2013-11-01

    Full Text Available We describe the presence of the bivalve Modiolarca lateralis (Say, 1822 in six tropical ascidians Ascidia curvata, A. sydneiensis, A. panamensis, A. interrupta, Herdmania pallida and Polycarpa spongiabilis collected at depths of 1-3 m on coral reefs, mangrove roots and dock supports in Almirante Bay, Bocas del Toro, Panama (9°18'N, 82°13'W during June-July 2011. Bivalve prevalence varied between 9-30% across species, but was mainly associated with A. panamensis, P. spongiabilis and A. interrupta. Prevalence seems to be influenced by tunic thickness rather than by the ascidian size. Bivalves varied in size (0.6-11 mm shell length, with the smallest individual found in A. sydneiensis. There were only one or two bivalves per ascidians, although a maximum of 18 was found in one A. panamensis. M. lateralis seems to behave similarly to its temperate counterparts: it has a variety of hosts, occurs mainly in the anterior region of the ascidians, and has a variable abundance per host.

  7. Sessile macro-epibiotic community of solitary ascidians, ecosystem engineers in soft substrates of Potter Cove, Antarctica

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    Clara Rimondino

    2015-01-01

    Full Text Available The muddy bottoms of inner Potter Cove, King George Island (Isla 25 de Mayo, South Shetlands, Antarctica, show a high density and richness of macrobenthic species, particularly ascidians. In other areas, ascidians have been reported to play the role of ecosystem engineers, as they support a significant number of epibionts, increasing benthic diversity. In this study, a total of 21 sessile macro-epibiotic taxa present on the ascidian species Corella antarctica Sluiter, 1905, Cnemidocarpa verrucosa (Lesson, 1830 and Molgula pedunculata Herdman, 1881 were identified, with Bryozoa being the most diverse. There were differences between the three ascidian species in terms of richness, percent cover and diversity of sessile macro-epibionts. The morphological characteristics of the tunic surface, the available area for colonization (and its relation with the age of the basibiont individuals and the pH of the ascidian tunic seem to explain the observed differences. Recent environmental changes in the study area (increase of suspended particulate matter caused by glaciers retreat have been related to observed shifts in the benthic community structure, negatively affecting the abundance and distribution of the studied ascidian species. Considering the diversity of sessile macro-epibionts found on these species, the impact of environmental shifts may be greater than that estimated so far.

  8. Seismic air gun exposure during early-stage embryonic development does not negatively affect spiny lobster Jasus edwardsii larvae (Decapoda: Palinuridae).

    Science.gov (United States)

    Day, Ryan D; McCauley, Robert D; Fitzgibbon, Quinn P; Semmens, Jayson M

    2016-03-07

    Marine seismic surveys are used to explore for sub-seafloor oil and gas deposits. These surveys are conducted using air guns, which release compressed air to create intense sound impulses, which are repeated around every 8-12 seconds and can travel large distances in the water column. Considering the ubiquitous worldwide distribution of seismic surveys, the potential impact of exposure on marine invertebrates is poorly understood. In this study, egg-bearing female spiny lobsters (Jasus edwardsii) were exposed to signals from three air gun configurations, all of which exceeded sound exposure levels (SEL) of 185 dB re 1 μPa(2) · s. Lobsters were maintained until their eggs hatched and the larvae were then counted for fecundity, assessed for abnormal morphology using measurements of larval length and width, tested for larval competency using an established activity test and measured for energy content. Overall there were no differences in the quantity or quality of hatched larvae, indicating that the condition and development of spiny lobster embryos were not adversely affected by air gun exposure. These results suggest that embryonic spiny lobster are resilient to air gun signals and highlight the caution necessary in extrapolating results from the laboratory to real world scenarios or across life history stages.

  9. Morula cells and non-self recognition in the compound ascidian Botryllus schlosseri

    Directory of Open Access Journals (Sweden)

    L Ballarin

    2005-01-01

    Full Text Available In the ascidian Botryllus schlosseri, we studied the effects of hemocyte incubation with foreigncells, such as bacteria, bacterial spores and yeast. In the presence of yeast and bacterial spores,morula cells, a common cell type in botryllid ascidians, changed their morphology, releasephenoloxidase in the medium, thus causing an increase in cytotoxicity, and express moleculesrecognised by anti-IL-1-a- and anti-TNF-a-antibodies. These effects were not observed whenhemocytes were incubated with both gram-positive (Staphylococcus aureus and gram-negative(Escherichia coli bacteria. Considering that morula cells are the main source of molecules recognisedby anti-cytokine-antibodies we suggest an immunosurveillance role of these cells, which may influenceimmune responses such as phagocytosis.

  10. Ascidian introductions through the Suez Canal: The case study of an Indo-Pacific species.

    Science.gov (United States)

    Rius, Marc; Shenkar, Noa

    2012-10-01

    Although marine biological invasions via the Suez Canal have been extensively documented, little is known about the introduction of non-indigenous ascidians (Chordata, Ascidiacea), a group containing particularly aggressive invasive species. Here, we used a multidisciplinary approach to study the introduction of the ascidian Herdmania momus into the Mediterranean Sea. We reviewed its taxonomy and global distribution, and analyzed how genetic variation is partitioned between sides of the Suez Canal. The taxonomic revision showed that H. momus currently has a wide Indo-Pacific distribution. Genetic data indicated two well-differentiated colonization histories across the eastern Mediterranean. Our findings suggest that the range expansion of H. momus has been greatly facilitated by the combined effect of human-mediated transport and the species' ability to adapt to different environments. The integrative approach presented here is critical to attain a holistic understanding of marine biological invasions, especially when studying groups with a poorly resolved taxonomy.

  11. Distribution and Localised Effects of the Invasive Ascidian Didemnum perlucidum (Monniot 1983) in an Urban Estuary

    Science.gov (United States)

    Wernberg, Thomas; McDonald, Justin I.

    2016-01-01

    Didemnid ascidians are notorious marine invaders, fouling infrastructure in many ecosystems globally. However, there have been few reports of direct interactions with native species in their natural environment. The invasive colonial ascidian Didemnum perlucidum was discovered in the Swan River estuary (Western Australia) growing on the native seagrass Halophila ovalis. Given the known effects of other related Didemnum species it was expected that D. perlucidum could adversely affect the seagrass, with possible flow on effects to the rest of the ecosystem. This study aimed to document the distribution and abundance of D. perlucidum in the estuary, and to determine whether this species had a negative impact on H. ovalis or associated flora and fauna. D. perlucidum was largely present near areas of infrastructure, particularly mooring buoys, suggesting these were the source of D. perlucidum recruits on the seagrasses. It showed a clear seasonal pattern in abundance, with highly variable cover and colony size. D. perlucidum had a measurable effect on H. ovalis, with colonies enveloping all plant tissue, likely restricting the photosynthetic ability of individual leaves and total plant biomass. There were also significantly less seagrass-associated mud snails (Batillaria australis) where D. perlucidum cover was high. These results demonstrate the ability of invasive ascidians to colonise and affect native seagrasses and associated biota. Seagrasses are pivotal to the ecological function of many urban estuaries world-wide. Biodiversity in these systems is already vulnerable to multiple stressors from human activities but the potential stress of fouling ascidians may pose an additional and increasing threat in the future. PMID:27144600

  12. Distribution and Localised Effects of the Invasive Ascidian Didemnum perlucidum (Monniot 1983) in an Urban Estuary.

    Science.gov (United States)

    Simpson, Tiffany Schenk; Wernberg, Thomas; McDonald, Justin I

    2016-01-01

    Didemnid ascidians are notorious marine invaders, fouling infrastructure in many ecosystems globally. However, there have been few reports of direct interactions with native species in their natural environment. The invasive colonial ascidian Didemnum perlucidum was discovered in the Swan River estuary (Western Australia) growing on the native seagrass Halophila ovalis. Given the known effects of other related Didemnum species it was expected that D. perlucidum could adversely affect the seagrass, with possible flow on effects to the rest of the ecosystem. This study aimed to document the distribution and abundance of D. perlucidum in the estuary, and to determine whether this species had a negative impact on H. ovalis or associated flora and fauna. D. perlucidum was largely present near areas of infrastructure, particularly mooring buoys, suggesting these were the source of D. perlucidum recruits on the seagrasses. It showed a clear seasonal pattern in abundance, with highly variable cover and colony size. D. perlucidum had a measurable effect on H. ovalis, with colonies enveloping all plant tissue, likely restricting the photosynthetic ability of individual leaves and total plant biomass. There were also significantly less seagrass-associated mud snails (Batillaria australis) where D. perlucidum cover was high. These results demonstrate the ability of invasive ascidians to colonise and affect native seagrasses and associated biota. Seagrasses are pivotal to the ecological function of many urban estuaries world-wide. Biodiversity in these systems is already vulnerable to multiple stressors from human activities but the potential stress of fouling ascidians may pose an additional and increasing threat in the future.

  13. When shape matters: strategies of different Antarctic ascidians morphotypes to deal with sedimentation.

    Science.gov (United States)

    Torre, Luciana; Abele, Doris; Lagger, Cristian; Momo, Fernando; Sahade, Ricardo

    2014-08-01

    Climate change leads to increased melting of tidewater glaciers in the Western Antarctic Peninsula region and sediment bearing glacial melt waters negatively affects filter feeding species as solitary ascidians. In previous work the erect-forms Molgula pedunculata and Cnemidocarpa verrucosa (Order Stolidobranchiata) appeared more sensitive than the flat form Ascidia challengeri (Order Phlebobranchiata). Sedimentation exposure is expected to induce up-regulation of anaerobic metabolism by obstructing the organs of gas exchange (environmental hypoxia) or causes enhanced squirting activity (functional hypoxia). In this study we evaluated the possible relationship between ascidian morphotype and their physiological response to sedimentation. Together with some behavioural observations, we analysed the response of anaerobic metabolic parameters (lactate formation and glycogen consumption) in different tissues of three Antarctic ascidians, exposed to high sediment concentrations (200 mgL(-1)). The results were compared to experimental hypoxia (10% pO2) and exercise (induced muscular contraction) effects, in order to discriminate the effect of sediment on each species and morpho-type (erect vs. flat forms). Our results suggest that the styled (erect) C. verrucosa increases muscular squirting activity in order to expulse excessive material, while the flat-form A. challengeri reacts more passively by down-regulating its aerobic metabolism under sediment exposure. Contrary, the erect ascidian M. pedunculata did not show any measurable response to the treatments, indicating that filtration and ingestion activities were not reduced or altered even under high sedimentation (low energetic material) which could be disadvantageous on the long-term and could explain why M. pedunculata densities decline in the study area.

  14. New records of Aplousobranch ascidians to Indian waters from Andaman Islands

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    Jhimli Mondal

    2017-02-01

    Full Text Available Aplousobranchia represents the largest order under the class Ascidiacea.  Two reef associated aplousobranch ascidians, Rhopalaea macrothorax Tokioka, 1953 under the family Diazonidae and Clavelina robusta Kott, 1990 under the family Clavelinidae, found from the Andaman group of islands are reported as new records to the Indian waters.  The present paper describes the taxonomic characters and distribution of these two newly recorded species.

  15. Distribution and Localised Effects of the Invasive Ascidian Didemnum perlucidum (Monniot 1983 in an Urban Estuary.

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    Tiffany Schenk Simpson

    Full Text Available Didemnid ascidians are notorious marine invaders, fouling infrastructure in many ecosystems globally. However, there have been few reports of direct interactions with native species in their natural environment. The invasive colonial ascidian Didemnum perlucidum was discovered in the Swan River estuary (Western Australia growing on the native seagrass Halophila ovalis. Given the known effects of other related Didemnum species it was expected that D. perlucidum could adversely affect the seagrass, with possible flow on effects to the rest of the ecosystem. This study aimed to document the distribution and abundance of D. perlucidum in the estuary, and to determine whether this species had a negative impact on H. ovalis or associated flora and fauna. D. perlucidum was largely present near areas of infrastructure, particularly mooring buoys, suggesting these were the source of D. perlucidum recruits on the seagrasses. It showed a clear seasonal pattern in abundance, with highly variable cover and colony size. D. perlucidum had a measurable effect on H. ovalis, with colonies enveloping all plant tissue, likely restricting the photosynthetic ability of individual leaves and total plant biomass. There were also significantly less seagrass-associated mud snails (Batillaria australis where D. perlucidum cover was high. These results demonstrate the ability of invasive ascidians to colonise and affect native seagrasses and associated biota. Seagrasses are pivotal to the ecological function of many urban estuaries world-wide. Biodiversity in these systems is already vulnerable to multiple stressors from human activities but the potential stress of fouling ascidians may pose an additional and increasing threat in the future.

  16. PSP toxins profile in ascidian Microcosmus vulgaris (Heller, 1877) after human poisoning in Croatia (Adriatic Sea).

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    Roje-Busatto, Romana; Ujević, Ivana

    2014-03-01

    Toxins known to cause Paralytic Shellfish Poisoning (PSP) syndrome in humans that can have serious economic consequences for aquaculture were determined in ascidians of the genus Microcosmus. Significant concentrations of toxins were confirmed in all tested samples collected from the western coast of Istria Peninsula (Adriatic Sea, Croatia) when six people were poisoned following the consumption of fresh ascidians. Several species of bivalves that were under continuous monitoring had not accumulated PSP toxins although they were exposed to the same environmental conditions over the survey period. In the present study, HPLC-FLD with pre-column oxidation of PSP toxins has been carried out to provide evidence for the first human intoxication due to consumption of PSP toxic ascidians (Microcosmus vulgaris, Heller, 1877) harvested from the Adriatic Sea. Qualitative analysis established the presence of six PSP toxins: saxitoxin (STX), decarbamoylsaxitoxin (dcSTX), gonyautoxins 2 and 3 (GTX2,3), decarbamoylgonyautoxins 2 and 3 (dcGTX2,3), gonyautoxin 5 (GTX5) and N-sulfocarbamoylgonyautoxins 1 and 2 (C1,2), while quantitative analysis suggested STX and GTX2,3 as dominant toxin types and the ones that contribute the most to the overall toxicity of these samples with concentrations near the regulatory limit.

  17. Occurrence and possible biological role of the endocannabinoid system in the sea squirt Ciona intestinalis.

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    Matias, Isabel; McPartland, John M; Di Marzo, Vincenzo

    2005-06-01

    A cannabinoid receptor orthologue (CiCBR) has been described in the sea squirt Ciona intestinalis. Here we report that CiCBR mRNA expression is highest in cerebral ganglion, branchial pharynx, heart and testis of C. intestinalis, and that this organism also contains cannabinoid receptor ligands and some of the enzymes for ligand biosynthesis and inactivation. Using liquid chromatography-mass spectrometry, the endocannabinoid anandamide was found in all tissues analysed (0.063-5.423 pmol/mg of lipid extract), with the highest concentrations being found in brain and heart. The endocannabinoid 2-arachidonoylglycerol (2-AG) was fivefold more abundant than anandamide, and was most abundant in stomach and intestine and least abundant in heart and ovaries (2.677-50.607 pmol/mg of lipid extract). Using phylogenomic analysis, we identified orthologues of several endocannabinoid synthesizing and degrading enzymes. In particular, we identified and partly sequenced a fatty acid amide hydrolase (FAAH) orthologue, showing 44% identity with human FAAH and containing nearly all the amino acids necessary for a functional FAAH enzyme. Ciona intestinalis also contained specific binding sites for cannabinoid receptor ligands, and an amidase enzyme with pH-dependency and subcellular/tissue distribution similar to mammalian FAAHs. Finally, a typical C. intestinalis behavioural response, siphon reopening after closure induced by mechanical stimulation, was inhibited by the cannabinoid receptor agonist HU-210, and this effect was significantly attenuated by mammalian cannabinoid receptor antagonists.

  18. A saturation screen for cis-acting regulatory DNA in the Hox genes of Ciona intestinalis

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    Keys, David N.; Lee, Byung-in; Di Gregorio, Anna; Harafuji, Naoe; Detter, Chris; Wang, Mei; Kahsai, Orsalem; Ahn, Sylvia; Arellano, Andre; Zhang, Quin; Trong, Stephan; Doyle, Sharon A.; Satoh, Noriyuki; Satou, Yutaka; Saiga, Hidetoshi; Christian, Allen; Rokhsar, Dan; Hawkins, Trevor L.; Levine, Mike; Richardson, Paul

    2005-01-05

    A screen for the systematic identification of cis-regulatory elements within large (>100 kb) genomic domains containing Hox genes was performed by using the basal chordate Ciona intestinalis. Randomly generated DNA fragments from bacterial artificial chromosomes containing two clusters of Hox genes were inserted into a vector upstream of a minimal promoter and lacZ reporter gene. A total of 222 resultant fusion genes were separately electroporated into fertilized eggs, and their regulatory activities were monitored in larvae. In sum, 21 separable cis-regulatory elements were found. These include eight Hox linked domains that drive expression in nested anterior-posterior domains of ectodermally derived tissues. In addition to vertebrate-like CNS regulation, the discovery of cis-regulatory domains that drive epidermal transcription suggests that C. intestinalis has arthropod-like Hox patterning in the epidermis.

  19. Dynamics of cell polarity in tissue morphogenesis: a comparative view from Drosophila and Ciona.

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    Veeman, Michael T; McDonald, Jocelyn A

    2016-01-01

    Tissues in developing embryos exhibit complex and dynamic rearrangements that shape forming organs, limbs, and body axes. Directed migration, mediolateral intercalation, lumen formation, and other rearrangements influence the topology and topography of developing tissues. These collective cell behaviors are distinct phenomena but all involve the fine-grained control of cell polarity. Here we review recent findings in the dynamics of polarized cell behavior in both the Drosophila ovarian border cells and the Ciona notochord. These studies reveal the remarkable reorganization of cell polarity during organ formation and underscore conserved mechanisms of developmental cell polarity including the Par/atypical protein kinase C (aPKC) and planar cell polarity pathways. These two very different model systems demonstrate important commonalities but also key differences in how cell polarity is controlled in tissue morphogenesis. Together, these systems raise important, broader questions on how the developmental control of cell polarity contributes to morphogenesis of diverse tissues across the metazoa.

  20. Introduced and native Phlebobranch and Stolidobranch solitary ascidians (Tunicata: Ascidiacea around Salvador, Bahia, Brazil

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    Rosana M. Rocha

    2012-02-01

    Full Text Available The Port of Salvador (12°58'S, 38°30'W receives cargo ships from different regions such as southeast Asia, North Atlantic, Mediterranean, Africa, North and South America. Thus, the presence of this port enhances the probability of new species arriving and establishing in Todos os Santos Bay (TSB, in which the port is located. Ascidians are sessile filter-feeding invertebrates with short lived larvae and thus are good indicators of bioinvasion. We surveyed the ascidian fauna on three different occasions: August 1999, June 2004 and December 2007. Nineteen species were identified belonging to the following families: Ascidiidae (Phallusia nigra, Ascidia cf. multitentaculata, A. nordestina, A. papillata, A. scalariforme, A. cf. tapuni, A. tenue, Corellidae (Rhodosoma turcicum, Pyuridae (Microcosmus anchylodeirus, M. exasperatus, M. helleri, Pyura vittata, Herdmania pallida, and Styelidae (Polycarpa cf. reviviscens, P. spongiabilis, P. tumida, Polycarpa sp., Styela canopus, Cnemidocarpa irene. Only A. nordestina, A. papillata, A. scalariforme and P. spongiabilis are possibly native to this region, while P. tumida and C. irene were classified as introduced. Microcosmus anchylodeirus, H. pallida, P. vittata, M. exasperatus, M. helleri, S. canopus, A. cf. multitentaculata, A. tenue and P. nigra were classified as cryptogenic. Most are widely distributed in all oceans and their native geographic distribution is unknown, while A. cf. multitentaculata and A. tenue occur only in the Atlantic, with disjunct distributions. Polycarpa cf. reviviscens, P. tumida and M. anchylodeirus are registered for the first time on the coast of Brazil. Colonial ascidians from this collection are still being studied. The large number of cryptogenic and introduced species indicates the necessity of monitoring TSB for expansion of these populations and the need for the establishment of control programs.

  1. Didemnaketals F and G, New Bioactive Spiroketals from a Red Sea Ascidian Didemnum Species

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    Lamiaa A. Shaala

    2014-09-01

    Full Text Available In continuation of our ongoing efforts to identify bioactive compounds from Red Sea marine organisms, a new collection of the ascidian Didemnum species was investigated. Chromatographic fractionation and HPLC purification of the CH2Cl2 fraction of an organic extract of the ascidian resulted in the identification of two new spiroketals, didemnaketals F (1 and G (2. The structure determination of the compounds was completed by extensive study of 1D (1H, 13C, and DEPT and 2D (COSY, HSQC, and HMBC NMR experiments in addition to high-resolution mass spectral data. Didemnaketal F (1 and G (2 differ from the previously reported compounds of this class by the lack the terminal methyl ester at C-1 and the methyl functionality at C-2. Instead, 1 and 2 possess a methyl ketone moiety instead of the terminal ester. Furthermore, didemnaketal F possesses a disubstituted double bond between C-2 and C-3, while the double bond was replaced by a secondary alcohol at C-3 in didemnaketal G. In addition, they possess the unique spiroketal/hemiketal functionality which was previously reported in didemnaketal E. Didemnaketals F (1 and G (2 displayed moderate activity against HeLa cells with of IC50s of 49.9 and 14.0 µM, respectively. In addition, didemnaketal F (1 displayed potent antimicrobial activity against E. coli and C. albicans. These findings provide further insight into the biosynthetic capabilities of this ascidian and the chemical diversity as well as the biological activity of this class of compounds.

  2. Nitric oxide acts as a positive regulator to induce metamorphosis of the ascidian Herdmania momus.

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    Nobuo Ueda

    Full Text Available Marine invertebrates commonly have a biphasic life cycle in which the metamorphic transition from a pelagic larva to a benthic post-larva is mediated by the nitric oxide signalling pathway. Nitric oxide (NO is synthesised by nitric oxide synthase (NOS, which is a client protein of the molecular chaperon heat shock protein 90 (HSP90. It is notable, then, that both NO and HSP90 have been implicated in regulating metamorphosis in marine invertebrates as diverse as urochordates, echinoderms, molluscs, annelids, and crustaceans. Specifically, the suppression of NOS activity by the application of either NOS- or HSP90-inhibiting pharmacological agents has been shown consistently to induce the initiation of metamorphosis, leading to the hypothesis that a negative regulatory role of NO is widely conserved in biphasic life cycles. Further, the induction of metamorphosis by heat-shock has been demonstrated for multiple species. Here, we investigate the regulatory role of NO in induction of metamorphosis of the solitary tropical ascidian, Herdmania momus. By coupling pharmacological treatments with analysis of HmNOS and HmHSP90 gene expression, we present compelling evidence of a positive regulatory role for NO in metamorphosis of this species, in contrast to all existing ascidian data that supports the hypothesis of NO as a conserved negative regulator of metamorphosis. The exposure of competent H. momus larvae to a NOS inhibitor or an NO donor results in an up-regulation of NOS and HSP90 genes. Heat shock of competent larvae induces metamorphosis in a temperature dependent manner, up to a thermal tolerance that approaches 35°C. Both larval/post-larval survival and the appearance of abnormal morphologies in H. momus post-larvae reflect the magnitude of up-regulation of the HSP90 gene in response to heat-shock. The demonstrated role of NO as a positive metamorphic regulator in H. momus suggests the existence of inter-specific adaptations of NO regulation

  3. Purification of mitochondrial proteins HSP60 and ATP synthase from ascidian eggs: implications for antibody specificity.

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    Janet Chenevert

    Full Text Available Use of antibodies is a cornerstone of biological studies and it is important to identify the recognized protein with certainty. Generally an antibody is considered specific if it labels a single band of the expected size in the tissue of interest, or has a strong affinity for the antigen produced in a heterologous system. The identity of the antibody target protein is rarely confirmed by purification and sequencing, however in many cases this may be necessary. In this study we sought to characterize the myoplasm, a mitochondria-rich domain present in eggs and segregated into tadpole muscle cells of ascidians (urochordates. The targeted proteins of two antibodies that label the myoplasm were purified using both classic immunoaffinity methods and a novel protein purification scheme based on sequential ion exchange chromatography followed by two-dimensional gel electrophoresis. Surprisingly, mass spectrometry sequencing revealed that in both cases the proteins recognized are unrelated to the original antigens. NN18, a monoclonal antibody which was raised against porcine spinal cord and recognizes the NF-M neurofilament subunit in vertebrates, in fact labels mitochondrial ATP synthase in the ascidian embryo. PMF-C13, an antibody we raised to and purified against PmMRF, which is the MyoD homolog of the ascidian Phallusia mammillata, in fact recognizes mitochondrial HSP60. High resolution immunolabeling on whole embryos and isolated cortices demonstrates localization to the inner mitochondrial membrane for both ATP synthase and HSP60. We discuss the general implications of our results for antibody specificity and the verification methods which can be used to determine unequivocally an antibody's target.

  4. 玻璃海鞘的营养成分分析%Analysis of Nutritional Components in Ciona intestinalis

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    时亚南; 郑秋生; 弭宝彬; 陈朋; 许波

    2011-01-01

    [Objective] The research aimed to analyze the nutritional components in Ciona intestinalis and evaluate their nutritional value. [ Method] The contents of moisture, fat, protein, and ash amino acids, fatty acids and minerals in Ciona intestinalis were determined by conventional methods. [Result] The contents of moisture, fat, protein and ash in Ciona intestinalis were 93.08% , 2.08% , 1.99% and 2.7%, respectively. 16 kinds of common amino acids in Ciona intestinalis were determined, among which glycine content was the highest, and the ratios of total essential amino acids to total amino acids and to non-essentialamino acids were 42. 51% and 73.94% , respectively. 18 kinds of common fatty acids were measured in Ciona intestinalis, including 8 saturated fatty acids, 3 non-unsaturated fatty acids and 3 poly unsaturated fatty acids . The contents of poly unsaturated fatty acids in fatty acids were 13. 8%. Fe, Zn, Mn, Cu, Ni and other elements were rich in Ciona intestinals. The detection and analysis of heavy metal elements and other toxic substances in Ciona intestinalis indicated that they met national safety and health standards. [Conclusion] Ciona intestinalis possess high nutritional value and promising prospects for further development.%[目的]分析测定了玻璃海鞘的营养成分,并对其营养价值进行了评价.[方法]采用常规方法测定了水分、脂肪、蛋白质、灰分、氨基酸、脂肪酸和矿物质含量.[结果]玻璃海鞘水分、脂肪、蛋白质和灰分分别为:93.08%、2.08%、1.99%和2.7%.共检测了16种氨基酸,其中甘氨酸含量最高,必需氨基酸占总氨基酸的比值为42.51%,必需氨基酸和非必需氨基酸的比值为73.94%,测定了玻璃海鞘中13种脂肪酸,其中饱和脂肪酸8种,单不饱和脂肪酸2种,多不饱和脂肪酸3种,多不饱和脂肪酸含量占脂肪酸总量的13.8%.玻璃海鞘中含有丰富的Fe、Zn、Mn、Cu、Ni等微量元素,对重金属等有毒有害

  5. Genome-wide identification and characterization of transcription start sites and promoters in the tunicate Ciona intestinalis.

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    Yokomori, Rui; Shimai, Kotaro; Nishitsuji, Koki; Suzuki, Yutaka; Kusakabe, Takehiro G; Nakai, Kenta

    2016-01-01

    The tunicate Ciona intestinalis, an invertebrate chordate, has recently emerged as a powerful model organism for gene regulation analysis. However, few studies have been conducted to identify and characterize its transcription start sites (TSSs) and promoters at the genome-wide level. Here, using TSS-seq, we identified TSSs at the genome-wide scale and characterized promoters in C. intestinalis. Specifically, we identified TSS clusters (TSCs), high-density regions of TSS-seq tags, each of which appears to originate from an identical promoter. TSCs were found not only at known TSSs but also in other regions, suggesting the existence of many unknown transcription units in the genome. We also identified candidate promoters of 79 ribosomal protein (RP) genes, each of which had the major TSS in a polypyrimidine tract and showed a sharp TSS distribution like human RP gene promoters. Ciona RP gene promoters, however, did not appear to have typical TATA boxes, unlike human RP gene promoters. In Ciona non-RP promoters, two pyrimidine-purine dinucleotides, CA and TA, were frequently used as TSSs. Despite the absence of CpG islands, Ciona TATA-less promoters showed low expression specificity like CpG-associated human TATA-less promoters. By using TSS-seq, we also predicted trans-spliced gene TSSs and found that their downstream regions had higher G+T content than those of non-trans-spliced gene TSSs. Furthermore, we identified many putative alternative promoters, some of which were regulated in a tissue-specific manner. Our results provide valuable information about TSSs and promoter characteristics in C. intestinalis and will be helpful in future analysis of transcriptional regulation in chordates.

  6. Differentiation of papillae and rostral sensory neurons in the larva of the ascidian Botryllus schlosseri (Tunicata).

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    Caicci, Federico; Zaniolo, Giovanna; Burighel, Paolo; Degasperi, Valentina; Gasparini, Fabio; Manni, Lucia

    2010-02-15

    During the metamorphosis of tunicate ascidians, the swimming larva uses its three anterior papillae to detect the substrate for settlement, reabsorbs its chordate-like tail, and becomes a sessile oozooid. In view of the crucial role played by the anterior structures and their nerve relations, we applied electron microscopy and immunocytochemistry to study the larva of the colonial ascidian Botryllus schlosseri, following differentiation of the anterior epidermis during late embryogenesis, the larval stage, and the onset of metamorphosis. Rudiments of the papillae appear in the early tail-bud stage as ectodermic protrusions, the apexes of which differentiate into central and peripheral bipolar neurons. Axons fasciculate into two nerves direct to the brain. Distally, the long, rod-like dendritic terminations extend during the larval stage, becoming exposed to sea water. After the larva selects and adheres to the substrate, these neurons retract and regress. Adjacent to the papillae, other scattered neurons insinuate dendrites into the tunic and form the net of rostral trunk epidermal neurons (RTENs) which fasciculate together with the papillary neurons. Our data indicate that the papillae are simple and coniform, the papillary neurons are mechanoreceptors, and the RTENs are chemoreceptors. The interpapillary epidermal area, by means of an apocrine secretion, provides sticky material for temporary adhesion of the larva to the substrate.

  7. Evolution and development of budding by stem cells: ascidian coloniality as a case study.

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    Brown, Federico D; Swalla, Billie J

    2012-09-15

    The evolution of budding in metazoans is not well understood on a mechanistic level, but is an important developmental process. We examine the evolution of coloniality in ascidians, contrasting the life histories of solitary and colonial forms with a focus on the cellular and developmental basis of the evolution of budding. Tunicates are an excellent group to study colonial transitions, as all solitary larvae develop with determinant and invariant cleavage patterns, but colonial species show robust developmental flexibility during larval development. We propose that acquiring new stem cell lineages in the larvae may be a preadaptation necessary for the evolution of budding. Brooding in colonial ascidians allows increased egg size, which in turn allows greater flexibility in the specification of cells and cell numbers in late embryonic and pre-metamorphic larval stages. We review hypotheses for changes in stem cell lineages in colonial species, describe what the current data suggest about the evolution of budding, and discuss where we believe further studies will be most fruitful.

  8. Expression and function of myc during asexual reproduction of the budding ascidian Polyandrocarpa misakiensis.

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    Fujiwara, Shigeki; Isozaki, Takaomi; Mori, Kyoko; Kawamura, Kazuo

    2011-12-01

    The budding ascidian Polyandrocarpa misakiensis proliferates asexually by budding. The atrial epithelium is a multipotent but differentiated tissue, which transdifferentiates into various tissues and organs after the bud separates from the parental body. We isolated cDNA clones homologous to the myc proto-oncogene from P. misakiensis. The cDNA, named Pm-myc, encoded a polypeptide of 639 amino acid residues, containing Myc-specific functional motifs, Myc box I and Myc box II, and the basic helix-loop-helix domain. Expression of Pm-myc was observed in the atrial epithelium in the organ-forming region of the developing bud, where the epithelial cells dedifferentiate and re-enter the cell cycle. The expression was also observed in fibroblast-like cells, which are known to participate in the organogenesis together with the epithelial cells. Unexpectedly, the atrial epithelium expressed Pm-myc more than one day before the dedifferentiation. The organogenesis was disturbed by Pm-myc-specific double-stranded RNA. In situ hybridization revealed that Pm-myc-positive fibroblast-like cells disappeared around the organ primordium of the dsRNA-treated bud. The results suggest that the mesenchymal-epithelial transition of fibroblast-like cells is important for the organogenesis in this budding ascidian species.

  9. Bacterial community in the tunic matrix of a colonial ascidian Diplosoma migrans

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    Groepler, Wolfgang; Schuett, Christian

    2003-06-01

    This paper provides the first information on the morphology of different morphotypes of bacteria in the tunic matrix of the colonial ascidian Diplosoma migrans. Ascidians were collected from waters near Helgoland (German Bight, North Sea). The dominant type is represented by extremely high numbers of long, needle-like rods (length 10-30 µm, width 0.5 µm). The bacteria are motile by means of bipolar monotrichous flagella, generating swift sigmoidal movement. Bacteria are already present during different embryonic stages. It is assumed that they are transferred during sexual propagation from the parental colony to its offspring. As a second morphotype, the tunic harbors screw-like bacteria in low numbers (length 4-10 µm, width 0.5 µm). Besides these conspicuous morphotypes, occasionally motile rods with spore-like globules at one end and additional coccoid forms in large quantities of unknown meaning (possibly spores) were found. The taxonomic status and ecological functions of these differently shaped bacterial groups are unclear.

  10. The recently-described ascidian species Molgula tectiformis is a direct developer.

    Science.gov (United States)

    Tagawa, K; Jeffery, W R; Satoh, N

    1997-04-01

    Molgula tectiformis is a new ascidian species recently described by Nishikawa (1991). In Otsuchi Bay, Iwate, Japan, they are easily obtainable from cages for culturing scallops. We report here that M. tectiformis is another example of a direct developer: their embryonic development is lacking the tadpole larva. The fertilized egg is orange and about 150 microns in diameter. At 18 degrees C, the egg cleaves at about 20 min intervals and gastrulation occurs about 5 hr after fertilization. In contrast to conventionally-developing ascidians, M. tectiformis does not form a tadpole larva. Immediately before hatching, three stolons or ampullae begin to extend from the tailless embryo. After hatching the stolons mediate the attachment of the juvenile body to the substratum. Histochemistry for tissue-specific enzyme activity did not detect muscle-specific acetyl-cholinesterase, endoderm-specific alkaline phosphatase, and pigment cell-specific tyrosinase. In addition, in situ hybridization could not prove the presence of muscle actin gene transcripts in the embryo. These results suggest that these larval tissues do not differentiate in M. tectiformis embryos. Because M. tectiformis is common and gravid year-around in Otsuchi Bay, this direct developer provides the opportunity for further analysis of molecular changes during evolution that cause an alternative mode of development.

  11. Dynamics of hemocyte subsets from ascidian Halocynthia aurantium in response to tissue damage: a comparative analysis of flow cytometry vs confocal microscopy data

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    AN Sukhachev

    2016-03-01

    Full Text Available The current study was aimed at investigating the dynamics of circulatory ascidian hemocyte subsets from Halocynthia aurantium in response to tunic damage. By using flow cytometry and confocal microscopy, it was demonstrated that the relative amount of hemoblasts and hyaline amebocytes was increased 24 h after cutting ascidian tunic and subjacent muscle layer. By applying a broad panel of fluorescently labeled monoclonal antibodies against human adhesion molecules expressed by lymphoid and stem cells both assays allowed to detect two cross-reactive epitopes (CD54 and CD90 on the surface of ascidian hemocytes. Upon that, the expression of CD54-like epitope was found to be downregulated on ascidian cells after tissue damage, whereas binding to CD90-like epitope was upregulated in all examined cell subsets.

  12. Urochordate ascidians possess a single isoform of Aurora kinase that localizes to the midbody via TPX2 in eggs and cleavage stage embryos.

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    Celine Hebras

    Full Text Available Aurora kinases are key proteins found throughout the eukaryotes that control mitotic progression. Vertebrate Aurora-A and B kinases are thought to have evolved from a single Aurora-kinase isoform closest to that found in present day urochordates. In urochordate ascidians Aurora binds both TPX2 (a vertebrate AURKA partner and INCENP (a vertebrate AURKB partner and localizes to centrosomes and spindle microtubules as well as chromosomes and midbody during both meiosis and mitosis. Ascidian Aurora also displays this localization pattern during mitosis in echinoderms, strengthening the idea that non-vertebrate deuterostomes such as the urochordates and echinoderms possess a single form of Aurora kinase that has properties of vertebrate Aurora-kinase A and B. In the ascidian, TPX2 localizes to the centrosome and the spindle poles also as in vertebrates. However, we were surprised to find that TPX2 also localized strongly to the midbody in ascidian eggs and embryos. We thus examined more closely Aurora localization to the midbody by creating two separate point mutations of ascidian Aurora predicted to perturb binding to TPX2. Both forms of mutated Aurora behaved as predicted: neither localized to spindle poles where TPX2 is enriched. Interestingly, neither form of mutated Aurora localized to the midbody where TPX2 is also enriched, suggesting that ascidian Aurora midbody localization required TPX2 binding in ascidians. Functional analysis revealed that inhibition of Aurora kinase with a pharmacological inhibitor or with a dominant negative kinase dead form of Aurora caused cytokinesis failure and perturbed midbody formation during polar body extrusion. Our data support the view that vertebrate Aurora-A and B kinases evolved from a single non-vertebrate deuterostome ancestor. Moreover, since TPX2 localizes to the midbody in ascidian eggs and cleavage stage embryos it may be worthwhile re-assessing whether Aurora A kinase or TPX2 localize to the midbody

  13. A genomic overview of short genetic variations in a basal chordate, Ciona intestinalis

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    Satou Yutaka

    2012-05-01

    Full Text Available Abstract Background Although the Ciona intestinalis genome contains many allelic polymorphisms, there is only limited data analyzed systematically. Establishing a dense map of genetic variations in C. intestinalis is necessary not only for linkage analysis, but also for other experimental biology including molecular developmental and evolutionary studies, because animals from natural populations are typically used for experiments. Results Here, we identified over three million candidate short genomic variations within a 110 Mb euchromatin region among five C. intestinalis individuals. The average nucleotide diversity was approximately 1.1%. Genetic variations were found at a similar density in intergenic and gene regions. Non-synonymous and nonsense nucleotide substitutions were found in 12,493 and 1,214 genes accounting for 81.9% and 8.0% of the entire gene set, respectively, and over 60% of genes in the single animal encode non-identical proteins between maternal and paternal alleles. Conclusions Our results provide a framework for studying evolution of the animal genome, as well as a useful resource for a wide range of C. intestinalis researchers.

  14. Raman spectroscopic imaging of the whole Ciona intestinalis embryo during development.

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    Mitsuru J Nakamura

    Full Text Available Intracellular composition and the distribution of bio-molecules play central roles in the specification of cell fates and morphogenesis during embryogenesis. Consequently, investigation of changes in the expression and distribution of bio-molecules, especially mRNAs and proteins, is an important challenge in developmental biology. Raman spectroscopic imaging, a non-invasive and label-free technique, allows simultaneous imaging of the intracellular composition and distribution of multiple bio-molecules. In this study, we explored the application of Raman spectroscopic imaging in the whole Ciona intestinalis embryo during development. Analysis of Raman spectra scattered from C. intestinalis embryos revealed a number of localized patterns of high Raman intensity within the embryo. Based on the observed distribution of bio-molecules, we succeeded in identifying the location and structure of differentiated muscle and endoderm within the whole embryo, up to the tailbud stage, in a label-free manner. Furthermore, during cell differentiation, we detected significant differences in cell state between muscle/endoderm daughter cells and daughter cells with other fates that had divided from the same mother cells; this was achieved by focusing on the Raman intensity of single Raman bands at 1002 or 1526 cm(-1, respectively. This study reports the first application of Raman spectroscopic imaging to the study of identifying and characterizing differentiating tissues in a whole chordate embryo. Our results suggest that Raman spectroscopic imaging is a feasible label-free technique for investigating the developmental process of the whole embryo of C. intestinalis.

  15. Preparation and Antitumor Activity of CS5931, A Novel Polypeptide from Sea Squirt Ciona Savignyi

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    Xiaoshuang Chen

    2016-03-01

    Full Text Available CS5931 is a novel anticancer agent isolated from the sea squirt Ciona savignyi. However, its content in the species is very low, and developing a novel approach for production of the polypeptide is promising. In the present study, we expressed and purified the polypeptide from E. coli, and the fermentation conditions were studied using response surface methodology. The yield of CS5931 was increased from 2.0 to 7.5 mg/L. The denaturing and renaturation conditions were also studied. Using the optimized renaturation condition, the anticancer activity of refolding CS5931 was increased significantly; the value of IC50 was decreased from 23.2 to 11.6 μM. In vivo study using xenograft nude mice bearing HCT116 cancer cells revealed that CS5931 was able to inhibit the growth of tumor significantly. The study provides a useful approach for obtaining enough amount of CS5931 for further study. This study is also important for developing the polypeptide as a novel anticancer agent.

  16. Two New Tryptamine Derivatives, Leptoclinidamide and (--Leptoclinidamine B, from an Indonesian Ascidian Leptoclinides dubius

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    Michio Namikoshi

    2012-02-01

    Full Text Available Two new tryptamine-derived alkaloids, named as leptoclinidamide (1 and (--leptoclinidamine B (2, were isolated from an Indonesian ascidian Leptoclinides dubius together with C2-α-D-mannosylpyranosyl-L-tryptophan (3. The structure of 1 was assigned on the basis of spectroscopic data for 1 and its N-acetyl derivative (4. Compound 1 was an amide of tryptamine with two β-alanine units. Although the planar structure of 2 is identical to that of the known compound (+-leptoclinidamine B (5, compound 2 was determined to be the enantiomer of 5 based on amino acid analysis using HPLC methods. Compounds 1 to 4 were evaluated for cytotoxicity against two human cancer cell lines, HCT-15 (colon and Jurkat (T-cell lymphoma cells, but none of the compounds showed activity.

  17. Potential speciation of morphotypes in the photosymbiotic ascidian Didemnum molle in the Ryukyu Archipelago, Japan

    Science.gov (United States)

    Hirose, M.; Yokobori, S.; Hirose, E.

    2009-03-01

    Four morphotypes are recognized in the photosymbiotic ascidian Didemnum molle in the Ryukyu Archipelago: three color morphs (white, dark gray, and brown) of small-type colonies and one large-type colony (white with gray patches). The genetic variation among these four morphotypes was investigated by constructing phylogenetic trees based on a 401-bp fragment of the cytochrome oxidase subunit I (COI) gene of 29 specimens collected from five islands (Okinawajima, Sesokojima, Ikeijima, Kumejima, and Ishigakijima). The results support the monophyly of the genus Didemnum and that of the four morphotypes of D. molle. Moreover, the phylogenetic trees discriminated four clades corresponding to each morphotype. The geographic differences of the sequences were much smaller than the differences among the morphotypes, suggesting that the four morphotypes in D. molle are discrete sibling species.

  18. Characterization and transcription studies of a phytochelatin synthase gene from the solitary tunicate Ciona intestinalis exposed to cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Franchi, Nicola [Department of Biology, University of Padova, Padova (Italy); Department of Biological, Chemical, Pharmaceutical Science and Technology, University of Palermo, Palermo (Italy); Piccinni, Ester [Department of Biology, University of Padova, Padova (Italy); Ferro, Diana [Department of Biology, University of Padova, Padova (Italy); Institute for Evolution and Biodiversity, Westfälische Wilhelms-Universität, Münster (Germany); Basso, Giuseppe [Department of Woman and Child Health, University of Padova, Padova (Italy); Spolaore, Barbara [CRIBI Biotechnology Centre, University of Padova, Padova (Italy); Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padova (Italy); Santovito, Gianfranco, E-mail: gianfranco.santovito@unipd.it [Department of Biology, University of Padova, Padova (Italy); Ballarin, Loriano [Department of Biology, University of Padova, Padova (Italy)

    2014-07-01

    Highlights: • Ciona intestinalis have a functional phytochelatin synthase (PCS) gene (cipcs). • CiPCS amino acid sequence is phylogentically related to other metazoan PCSs. • CiPCS catalyze the synthesis of PC2. • cipcs are mostly transcribed in circulating hemocytes, in both tunic and blood lacunae. • Cadmium exposure results in a significant increase of cipcs and cipcna transcription. - Abstract: The major thiol-containing molecules involved in controlling the level of intracellular ROS in eukaryotes, acting as a nonenzymatic detoxification system, are metallothioneins (MTs), glutathione (GSH) and phytochelatins (PCs). Both MTs and GSH are well-known in the animal kingdom. PC was considered a prerogative of the plant kingdom but, in 2001, a phytochelatin synthase (PCS) gene was described in the nematode Caenorhabditis elegans; additional genes encoding this enzyme were later described in the earthworm Eisenia fetida and in the parasitic nematode Schistosoma mansoni but scanty data are available, up to now, for Deuterostomes. Here, we describe the molecular characteristics and transcription pattern, in the presence of Cd, of a PCS gene from the invertebrate chordate Ciona intestinalis, a ubiquitous solitary tunicate and demonstrate the presence of PCs in tissue extracts. We also studied mRNA localization by in situ hybridization. In addition, we analyzed the behavior of hemocytes and tunic cells consequent to Cd exposure as well as the transcription pattern of the Ciona orthologous for proliferating cell nuclear antigen (PCNA), usually considered a proliferation marker, and observed that cell proliferation occurs after 96 h of Cd treatment. This matches the hypothesis of Cd-induced cell proliferation, as already suggested by previous data on the expression of a metallothionein gene in the same animal.

  19. Evaluation of antibacterial activity of crude extracts of ascidian Didemnum psammathodes Sluiter, 1895 against isolated human and fish pathogens

    Institute of Scientific and Technical Information of China (English)

    N Sri Kumaran; S Bragadeeswaran; VK Meenakshi

    2011-01-01

    Objective: To evaluate the antimicrobial activities of ascidian Didemnum psammathodes (D. psammathodes) against human and fish pathogenic organisms. Methods: In this study antimicrobial activities were carried out by standard disc diffusion method. In this experiment 40 human, fish bacterial and fungal pathogens were isolated and assayed against 7 different solvents such as methanol, acetone, ethanol, n-butanol, chloroform, ethyl acetate and dichloromethane. Each solvent were assayed at different concentrations of 25, 50, 75, 100 mg/mL. Results: From this experiment solvent having higher concentrations showed high inhibition activity and the fungi are showed more resistant than the bacterial strains used. Conclusions: These results indicate that the ascidian D. psammathodes is found to have remarkable antimicrobial activities against isolated microbes. Further studies will fulfill for purification and structural elucidation of antimicrobial drugs.

  20. Microenvironmental Ecology of the Chlorophyll b-containing Symbiotic Cyanobacterium Prochloron in the Didemnid Ascidian Lissoclinum patella

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    Michael eKühl

    2012-11-01

    Full Text Available The discovery of the cyanobacterium Prochloron was the first finding of a bacterial oxyphototroph with chlorophyll (Chl b, in addition to Chl a. It was first described as Prochloron didemni but a number of clades have since been described. Prochloron is a conspicuously large (7-25 µm unicellular cyanobacterium living in a symbiotic relationship, primarily with (sub- tropical didemnid ascidians; it has resisted numerous cultivation attempts and appears truly obligatory symbiotic. Recently, a Prochloron draft genome was published, revealing no lack of metabolic genes that could explain the apparent inability to reproduce and sustain photosynthesis in a free-living stage. Possibly, the unsuccessful cultivation is partly due to a lack of knowledge about the microenvironmental conditions and ecophysiology of Prochloron in its natural habitat. We used microsensors, variable chlorophyll fluorescence imaging and imaging of O2 and pH to obtain a detailed insight to the microenvironmental ecology and photobiology of Prochloron in hospite in the didemnid ascidian Lissoclinum patella. The microenvironment within ascidians is characterized by steep gradients of light and chemical parameters that change rapidly with varying irradiances. The interior zone of the ascidians harboring Prochloron thus became anoxic and acidic within a few min of darkness, while the same zone exhibited O2 super-saturation and strongly alkaline pH after a few min of illumination. Photosynthesis showed lack of photoinhibition even at high irradiances equivalent to full sunlight, and photosynthesis recovered rapidly after periods of anoxia. We discuss these new insights on the ecological niche of Prochloron and possible interactions with its host and other microbes in light of its recently published genome and a recent study of the overall microbial diversity and metagenome of L. patella.

  1. Comparative study on bioremediation of heavy metals by solitary ascidian, Phallusia nigra, between Thoothukudi and Vizhinjam ports of India.

    Science.gov (United States)

    Abdul Jaffar Ali, H; Tamilselvi, M; Akram, A Soban; Kaleem Arshan, M L; Sivakumar, V

    2015-11-01

    Ascidians belonging to the sub-phylum Uro-chordata are used as potential model organisms in various parts of the world for biosorption of metals. The sedentary nature, filter feeding habits, presence of vanadocytes and the absence of kidneys cause them to accumulate metals. The present study was aimed to compare biosorption of metals such as cadmium, copper, lead, mercury and vanadium in test and mantle body of solitary ascidian Phallusia nigra between two ecologically significant stations such as Thoothukudi (Station 1) and Vizhinjam (Station 2) ports of India. Monthly samplings of water and P. nigra were done for a period of one year from September 2010 to August 2011 and subjected to analysis of metal accumulation. The average metal concentrations except mercury in the Thoothukudi water were found to be higher of comparable magnitudes than the Vizhinjam water. One-way ANOVA showed significant differences between the stations. A comparison of average metal concentrations in the test and mantle body of P. nigra between two stations showed that the enrichment of V, Cd, Pb, Cu and Hg in the Thoothukudi samples may be due to high bioaccumulation factors of these elements as compared to other species of ascidians. The bioaccumulation factors were in the order of V>Pb>Cd>Cu> Hg for the test and mantle body in stations 1 and 2. Application of one-way ANOVA for the concentration of these metals between test and mantle body showed significant differences in both stations. Similarly, ANOVA for biosorption of these trace metals by P. nigra showed significant difference between stations. Metal concentrations recorded in this ascidian could effectively be used as good reference material for monitoring metal contamination in Indian sea waters.

  2. Studies on the seasonal variations in the proximate composition of ascidians from the Palk Bay, Southeast coast of India

    Institute of Scientific and Technical Information of China (English)

    Ananthan G; Karthikeyan MM; Selva Prabhu A; Raghunathan C

    2012-01-01

    To investigate the seasonal fluctuations of the proximate composition of the ascidians muscle. Methods: The moisture content was estimated by drying 1 g of fresh tissue at a constant temperature at 105 ℃ for 24 h.The loss of weight was taken as moisture content. The total protein was estimated using the Biuret method. The total carbohydrate in dried sample was estimated spectrophotometrically following the phenol- sulphuric acid method. The lipid in the dried sample tissue was gravimetrically estimated following the chloroform-methanol mixture method. Ash content was determined gravimetrically by incinerating 1 g dried sample in muffle furnace at about 550 ℃ for 6 h and results are expressed in percentage. Results: It was found very difficult to compare the monthly variations, as all the ten species, exhibited wide fluctuations in their proximate compositions. For the sake of convenience, average seasonal values were calculated by summing the monthly values. Conclusions: The proximate composition of the 10 commonly available ascidians showed high nutritive value and hence these groups especially solitary ascidians can be recommended for human consumption in terms of pickles, soup, curry and others after ensuring the safety of consumers.

  3. Studies on the seasonal variations in the proximate composition of ascidians from the Palk Bay,Southeast coast of India

    Institute of Scientific and Technical Information of China (English)

    Ananthan; G; Karthikeyan; MM; Selva; Prabhu; A; Raghunathan; C

    2012-01-01

    Objective:To investigate the seasonal fluctuations of the proximate composition of the ascidians muscle.Methods:The moisture content was estimated by drying 1 g of fresh tissue at a constant temperature at 105(?)for 24 h.The loss of weight was taken as moisture content.The total protein was estimated using the Biuret method.The total carbohydrate in dried sample was estimated spectrophotometrically following the phenol-sulphuric acid method.The lipid in the dried sample tissue was gravimetrically estimated following the chloroform-methanol mixture method.Ash content was determined gravimetrically by incinerating 1 g dried sample in muffle furnace at about 550℃for 6 h and results are expressed in percentage.Results:It was found very difficult to compare the monthly variations,as all the ten species,exhibited wide fluctuations in their proximate compositions.For the sake of convenience,average seasonal values were calculated by summing the monthly values.Conclusions:The proximate composition of the 10 commonly available ascidians showed high nutritive value and hence these groups especially solitary ascidians can be recommended for human consumption in terms of pickles,soup,curry and others after ensuring the safety of consumers.

  4. Ciona intestinalis as a Marine Model System to Study Some Key Developmental Genes Targeted by the Diatom-Derived Aldehyde Decadienal

    Directory of Open Access Journals (Sweden)

    Anna Lettieri

    2015-03-01

    Full Text Available The anti-proliferative effects of diatoms, described for the first time in copepods, have also been demonstrated in benthic invertebrates such as polychaetes, sea urchins and tunicates. In these organisms PUAs (polyunsaturated aldehydes induce the disruption of gametogenesis, gamete functionality, fertilization, embryonic mitosis, and larval fitness and competence. These inhibitory effects are due to the PUAs, produced by diatoms in response to physical damage as occurs during copepod grazing. The cell targets of these compounds remain largely unknown. Here we identify some of the genes targeted by the diatom PUA 2-trans-4-trans-decadienal (DD using the tunicate Ciona intestinalis. The tools, techniques and genomic resources available for Ciona, as well as the suitability of Ciona embryos for medium-to high-throughput strategies, are key to their employment as model organisms in different fields, including the investigation of toxic agents that could interfere with developmental processes. We demonstrate that DD can induce developmental aberrations in Ciona larvae in a dose-dependent manner. Moreover, through a preliminary analysis, DD is shown to affect the expression level of genes involved in stress response and developmental processes.

  5. Ciona intestinalis as a marine model system to study some key developmental genes targeted by the diatom-derived aldehyde decadienal.

    Science.gov (United States)

    Lettieri, Anna; Esposito, Rosaria; Ianora, Adrianna; Spagnuolo, Antonietta

    2015-03-17

    The anti-proliferative effects of diatoms, described for the first time in copepods, have also been demonstrated in benthic invertebrates such as polychaetes, sea urchins and tunicates. In these organisms PUAs (polyunsaturated aldehydes) induce the disruption of gametogenesis, gamete functionality, fertilization, embryonic mitosis, and larval fitness and competence. These inhibitory effects are due to the PUAs, produced by diatoms in response to physical damage as occurs during copepod grazing. The cell targets of these compounds remain largely unknown. Here we identify some of the genes targeted by the diatom PUA 2-trans-4-trans-decadienal (DD) using the tunicate Ciona intestinalis. The tools, techniques and genomic resources available for Ciona, as well as the suitability of Ciona embryos for medium-to high-throughput strategies, are key to their employment as model organisms in different fields, including the investigation of toxic agents that could interfere with developmental processes. We demonstrate that DD can induce developmental aberrations in Ciona larvae in a dose-dependent manner. Moreover, through a preliminary analysis, DD is shown to affect the expression level of genes involved in stress response and developmental processes.

  6. From oocyte to 16-cell stage: cytoplasmic and cortical reorganizations that pattern the ascidian embryo.

    Science.gov (United States)

    Sardet, Christian; Paix, Alexandre; Prodon, François; Dru, Philippe; Chenevert, Janet

    2007-07-01

    The dorsoventral and anteroposterior axes of the ascidian embryo are defined before first cleavage by means of a series of reorganizations that reposition cytoplasmic and cortical domains established during oogenesis. These domains situated in the periphery of the oocyte contain developmental determinants and a population of maternal postplasmic/PEM RNAs. One of these RNAs (macho-1) is a determinant for the muscle cells of the tadpole embryo. Oocytes acquire a primary animal-vegetal (a-v) axis during meiotic maturation, when a subcortical mitochondria-rich domain (myoplasm) and a domain rich in cortical endoplasmic reticulum (cER) and maternal postplasmic/PEM RNAs (cER-mRNA domain) become polarized and asymmetrically enriched in the vegetal hemisphere. Fertilization at metaphase of meiosis I initiates a series of dramatic cytoplasmic and cortical reorganizations of the zygote, which occur in two major phases. The first major phase depends on sperm entry which triggers a calcium wave leading in turn to an actomyosin-driven contraction wave. The contraction concentrates the cER-mRNA domain and myoplasm in and around a vegetal/contraction pole. The precise localization of the vegetal/contraction pole depends on both the a-v axis and the location of sperm entry and prefigures the future site of gastrulation and dorsal side of the embryo. The second major phase of reorganization occurs between meiosis completion and first cleavage. Sperm aster microtubules and then cortical microfilaments cause the cER-mRNA domain and myoplasm to reposition toward the posterior of the zygote. The location of the posterior pole depends on the localization of the sperm centrosome/aster attained during the first major phase of reorganization. Both cER-mRNA and myoplasm domains localized in the posterior region are partitioned equally between the first two blastomeres and then asymmetrically over the next two cleavages. At the eight-cell stage the cER-mRNA domain compacts and gives rise to

  7. Alpha-amylase inhibitory activities of ascidians in the treatment of diabetes mellitus

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    Antonyraj Selva Prabhu

    2014-12-01

    Full Text Available Extracts of ten selected ascidians with a reputation of usefulness in treating diabetes were examined for alpha-amylase inhibition using an in vitro model. The extract with the highest activity was selected for further characterization. From the results ethyl acetate showed predominant amylase inhibition activity for all species and the maximum level of inhibition was recorded in Phallusia mammillata (68% at 300 µg/mL and the lowest activity was noted in Microcosmus squamiger (12% at 200 µg/mL. After preliminary results, the methanolic extract of P. mammallita were further assayed for confirmation of enzyme inhibition and the maximum results (82% were obtained at 250 µg/mL and the IC50 value of P. mammillata were evidenced at 145.0 ± 0.4 µg/g. In the present study, P. mammillata indicated the maximum α-amylase activity without toxic effects. Similarly, α-glucosidase and α-amylase inhibitor bromophenol, C6H5BrO was produced by P. mammillata.

  8. Botryllus schlosseri: a model ascidian for the study of asexual reproduction.

    Science.gov (United States)

    Manni, L; Zaniolo, G; Cima, F; Burighel, P; Ballarin, L

    2007-02-01

    Botryllus schlosseri, a cosmopolitan colonial ascidian reared in the laboratory for more than 50 years, reproduces both sexually and asexually and is used as a model organism for studying a variety of biological problems. Colonies are formed of numerous, genetically identical individuals (zooids) and undergo cyclical generation changes in which the adult zooids die and are replaced by their maturing buds. Because the progression of the colonial life cycle is intimately correlated with blastogenesis, a shared staging method of bud development is required to compare data coming from different laboratories. With the present review, we aim (1) to introduce B. schlosseri as a valuable chordate model to study various biological problems and, especially, sexual and asexual development; (2) to offer a detailed description of bud development up to adulthood and the attainment of sexual maturity; (3) to re-examine Sabbadin's (1955) staging method and re-propose it as a simple tool for in vivo recognition of the main morphogenetic events and recurrent changes in the blastogenetic cycle, as it refers to the developmental stages of buds and adults.

  9. Cytotoxicity of the Ascidian Cystodytes dellechiajei Against Tumor Cells and Study of the Involvement of Associated Microbiota in the Production of Cytotoxic Compounds

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    Josefa Antón

    2007-07-01

    Full Text Available Many cytotoxic compounds of therapeutic interest have been isolated from marine invertebrates, and some of them have been reported to be of microbial origin. Pyridoacridine alkaloids are the main compounds extracted from the ascidian Cystodytes dellechiajei. Here we describe the in vitro antiproliferative activity against different tumor cell lines of the ascidian extracts and provide some insights on the role of the microbial community associated with the tunicate in the production of these compounds. C. dellechiajei extracts showed remarkably high antiproliferative activity (IC50 ≤5 μg/mL in human lung carcinoma A-549, colon adenocarcinoma H-116, pancreatic adenocarcinoma PSN-1 and breast carcinoma SKBR3 cell lines. Moreover, we found that the maximum activity was located in the tunic tissue of the colony, which harbours a microbial community. In order to ascertain the involvement of this community in the synthesis of the bioactive compounds different approachs that included culture and culture independent methods were carried out. We undertook a screening for antiproliferative activities of the bacterial isolates from the ascidian, as well as a comprative analysis of the cytotoxic activities and the microbial communities from two color morphs of the ascidian, green and blue. In addition, the changes of the antiproliferative activities and the composition of the microbial communities were studied from ascidians kept in aquaria and treated with antibiotics for one month. Our data obtained from the different experiments did not point out to bacteria as the source of the cytotoxic compounds, suggesting thus an ascidian origin.

  10. Methods to eradicate soft tunic syndrome (STS)-causing protozoa Azumiobodo hoyamushi, the highly infectious parasite from the edible ascidian (Halocynthia roretzi)

    OpenAIRE

    Ji-Hoon Lee; Jae-Geun Lee; Seung-Ryul Zeon; Kyung-Il Park; Kwan Ha Park

    2016-01-01

    Abstract Although soft tunic syndrome (STS) in the ascidian is a serious disease, helpful measures have yet not been established. It was examined in this study by applying aniti-parasitic drugs to eradicate the causative protozoa Azumiobodo hoyamushi from infected ascidians. Formalin was synergistic in killing parasites in vitro when co-treated with hydrogen peroxide (H2O2) or bronopol, but not with chloramine-T or povidone-iodine (PVP-I), when tested with in vitro parasite culture. The syner...

  11. Isolation and Characterization of a Shewanella Phage–Host System from the Gut of the Tunicate, Ciona intestinalis

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    Brittany Leigh

    2017-03-01

    Full Text Available Outnumbering all other biological entities on earth, bacteriophages (phages play critical roles in structuring microbial communities through bacterial infection and subsequent lysis, as well as through horizontal gene transfer. While numerous studies have examined the effects of phages on free-living bacterial cells, much less is known regarding the role of phage infection in host-associated biofilms, which help to stabilize adherent microbial communities. Here we report the cultivation and characterization of a novel strain of Shewanella fidelis from the gut of the marine tunicate Ciona intestinalis, inducible prophages from the S. fidelis genome, and a strain-specific lytic phage recovered from surrounding seawater. In vitro biofilm assays demonstrated that lytic phage infection affects biofilm formation in a process likely influenced by the accumulation and integration of the extracellular DNA released during cell lysis, similar to the mechanism that has been previously shown for prophage induction.

  12. Dynamics of cell polarity in tissue morphogenesis: a comparative view from Drosophila and Ciona [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Michael T. Veeman

    2016-06-01

    Full Text Available Tissues in developing embryos exhibit complex and dynamic rearrangements that shape forming organs, limbs, and body axes. Directed migration, mediolateral intercalation, lumen formation, and other rearrangements influence the topology and topography of developing tissues. These collective cell behaviors are distinct phenomena but all involve the fine-grained control of cell polarity. Here we review recent findings in the dynamics of polarized cell behavior in both the Drosophila ovarian border cells and the Ciona notochord. These studies reveal the remarkable reorganization of cell polarity during organ formation and underscore conserved mechanisms of developmental cell polarity including the Par/atypical protein kinase C (aPKC and planar cell polarity pathways. These two very different model systems demonstrate important commonalities but also key differences in how cell polarity is controlled in tissue morphogenesis. Together, these systems raise important, broader questions on how the developmental control of cell polarity contributes to morphogenesis of diverse tissues across the metazoa.

  13. Maternal determinants and mRNAs in the cortex of ascidian oocytes, zygotes and embryos.

    Science.gov (United States)

    Sardet, Christian; Dru, Philippe; Prodon, François

    2005-01-01

    The peripheral region of ascidian oocytes and zygotes contains five determinants for morphogenesis and differentiation of the embryo. The determinant for the 24 primary muscle cells of the tadpole, macho1, is one of several cortical mRNAs localized in a gradient along the animal-vegetal axis in the oocyte. After fertilization these mRNAs, together with cortical endoplasmic reticulum (cER) and a subcortical mitochondria-rich domain (myoplasm), relocate in two major reorganization phases forming the posterior plasm (postplasm) of the zygote. At the 8-cell stage cortical mRNAs concentrate in a macroscopic cortical structure called the centrosome-attracting body (CAB), forming a characteristic posterior end mark (PEM) in the two posterior vegetal blastomeres. We propose to call the numerous mRNAs showing this particular cortical localization in the posterior region of the embryo postplasmic/PEM RNAs and suggest a nomemclature. We do not know how postplasmic/PEM RNAs reach their polarized distribution in the oocyte cortex but at least PEM1 and macho1 (and probably others) bind to the network of cER retained in isolated cortical fragments. We propose that after fertilization, these postplasmic/PEM mRNAs move in the zygote cortex together with the cER network (cER/mRNA domain) via microfilament- and microtubule-driven translocations. The cER/mRNA domain is localized posteriorly at the time of first cleavage and distributed equally between the first two blastomeres. After the third cleavage, the cER/mRNA domain and dense particles compact to form the CAB in posterior vegetal blastomeres of the 8-cell stage. We discuss the identity of postplasmic/PEM RNAs, how they localize, anchor, relocate and may be translated. We also examine their roles in unequal cleavage and as a source of posterior morphogenetic and differentiation factors.

  14. Non indigenous ascidians in port and natural environments in a tropical Brazilian bay

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    Flávia O. Marins

    2010-04-01

    Full Text Available Despite limited natural dispersal, some species of ascidians can be transported vast distances via oceanic petroleum platforms, ship hulls and ballast water and therefore may be good indicators of bioinvasion. Usually non indigenous species (NIS are abundant in harbors. This is caused in part because of the higher propagule delivery rate in these areas. An alternative explanation of why invasion is enhanced in harbor and marinas is that environmental degradation commonly found in these habitats favors the establishment of NIS. Most surveys for introduced species were not comprehensive and targeted mainly ports and marinas. Angra dos Reis is an excellent system that provides an opportunity to compare the potential distribution of introduced and native species of Ascidiacea between port and natural environments. Here, we compared the colonization of experimental subtidal plates placed in harbors and marinas with the colonization of plates placed in nearby natural areas. With 27 taxa (15 identified to species, species richness was greater in port environments (25 versus 8. Six taxa were common to both environments while 19 taxa were exclusively found in ports. Among the identified species in ports, three were introduced, five were cryptogenic and only one was native. Only three species were found exclusively in the natural sites and all were cryptogenic. The presence of introduced species only in the port areas of Angra dos Reis reinforces the need for continued, periodic monitoring in the region for early detection of new, potentially invasive, species as well as for better understanding of abnormal population growth of the already known species. Management to reduce the transfer of exotics to natural habitats must be implemented.

  15. Phylogenetics, biogeography and population genetics of the ascidian Botryllus schlosseri in the Mediterranean Sea and beyond.

    Science.gov (United States)

    Reem, Eitan; Douek, Jacob; Paz, Guy; Katzir, Gadi; Rinkevich, Baruch

    2017-02-01

    The wide distribution of the ascidian Botryllus schlosseri along the Mediterranean coasts has been documented since the eighteenth century. However, despite copious documentation, analyses of dispersal modes and genetic profiles were limited to local populations or restricted regions. In order to get a pan-Mediterranean overview, 288 specimens from 11 populations of B. schlosseri from the western and eastern Mediterranean basins were sampled and analyzed using five microsatellite loci and COI sequences. Both molecular markers revealed high polymorphisms, with 182 microsatellites alleles and 54 COI haplotypes. Overall, Fst, Dest, and COI Фpt values were 0.146, 0.635 and 0.322, respectively, reflecting a high genetic diversity and a significant genetic structure as compared to other B. schlosseri populations worldwide, reflected by substantially higher values for effective number of alleles (Ne) in the Mediterranean. A phylogenetic analysis of the COI sequences resulted in four distinct clades and two molecular operational taxonomic units (OTUs). We recorded a stronger genetic structure among the populations of the eastern basin compared to the western basin (microsatellites Fst=0.217 versus 0.082; COI Фpt=0.416 versus 0.171), suggesting either a restricted connectivity between the basins or a stronger genetic drift in each basin. The occurrence of two OTUs and different ecological conditions may also contribute to this finding. Mean Nei's genetic distance in the eastern Mediterranean populations was more than three times higher compared to the western basin. No correlation was observed between geographic and genetic distances (Mantel test), suggesting that maritime transport is the main dispersal vector of B. schlosseri colonies. The possibility that the Mediterranean is a center of diversity for B. schlosseri, and probably its site of origin, is further discussed.

  16. Biology of the invasive ascidian Ascidiella aspersa in its native habitat: Reproductive patterns and parasite load

    Science.gov (United States)

    Lynch, Sharon A.; Darmody, Grainne; O'Dwyer, Katie; Gallagher, Mary Catherine; Nolan, Sinead; McAllen, Rob; Culloty, Sarah C.

    2016-11-01

    The European sea squirt Ascidiella aspersa is a solitary tunicate native to the northeastern Atlantic, commonly found in shallow and sheltered marine ecosystems where it is capable of forming large clumps and outcompeting other invertebrate fauna at settlement. To date, there have been relatively few studies looking at the reproductive biology and health status of this invasive species. Between 2006 and 2010 sampling of a native population took place to investigate gametogenesis and reproductive cycle and to determine the impact of settlement depth on reproduction. In addition, parasite diversity and impact was assessed. A staging system to assess reproductive development was determined. The study highlighted that from year to year the tunicate could change its reproductive strategy from single sex to hermaphrodite, with spawning possible throughout the year. Depth did not impact on sex determination, however, gonad maturation and spawning occurred earlier in individuals in deeper waters compared to shallow depth and it also occurred later in A. aspersa at sites further away from the open sea. Four significant parasite groups including eugregarines, ciliates, trematodes and turbellarians were detected and prevalence of parasite infections increased in A. aspersa at sites with a reduced water flow rate. This study demonstrates the high biotic potential of this ascidian bioinvader to have a negative impact on native fauna in an introduced ecosystem, due to its highly efficient reproductive and resource allocation strategies. Artificial structures such as mooring lines can harbour large aggregations of A. aspersa, however, these manmade habitats may facilitate the colonisation and establishment of this invasive species in the benthos. Additionally, the parasite communities that A. aspersa harbour may also exacerbate its negative impact, both ecologically and economically, in an introduced area by possibly leading to the emergence of new disease in native species i

  17. Localization of CiCBR in the invertebrate chordate Ciona intestinalis: evidence of an ancient role for cannabinoid receptors as axonal regulators of neuronal signalling.

    Science.gov (United States)

    Egertová, Michaela; Elphick, Maurice R

    2007-06-01

    CiCBR is a G-protein-coupled receptor in the sea-squirt Ciona intestinalis and the first ortholog of vertebrate CB(1) and CB(2) cannabinoid receptors to be identified in an invertebrate (Elphick et al. [2003] Gene 302:95-101). Here we have used Western blotting and immunocytochemistry to examine expression of CiCBR in adult Ciona, employing novel antibodies to the C-terminal tail of CiCBR. Consistent with the expected mass for CiCBR, a approximately 47-kDa band was detected in Ciona membranes, and immunocytochemical analysis of serial sections of Ciona revealed intense immunoreactivity in the cerebral ganglion localised in a dense meshwork of fibers in the neuropile. Accordingly, Western blot analysis of neural complex homogenates revealed the presence of a approximately 47-kDa band. CiCBR immunoreactivity was also observed in axons exiting the ganglion in the anterior and posterior nerves, and analysis of whole-mount preparations revealed that these axons project over the interior surface of the oral and atrial siphons. Isolated CiCBR-immunoreactive axons not associated with the anterior and posterior nerves were observed projecting through the cortical layer of the cerebral ganglion. Central and peripheral CiCBR-immunoreactive fibers were studded with intensely stained varicosities, indicative of a role for CiCBR in regulation of axonal release of neurotransmitters, neuromodulators, or neurohormones. Collectively, our data suggest that the well-established role that the CB(1) receptor has as an axonal regulator of neurotransmitter release in mammals may have originated with ancestral-type cannabinoid receptors in invertebrate chordates before the emergence of CB(1)- and CB(2)-type receptors in vertebrates.

  18. Chemotactic response with a constant delay-time mechanism in Ciona spermatozoa revealed by a high time resolution analysis of flagellar motility

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    Daisuke Miyashiro

    2015-01-01

    Full Text Available During their chemotactic swimming toward eggs, sperm cells detect their species-specific chemoattractant and sense concentration gradients by unknown mechanisms. After sensing the attractant, sperm cells commonly demonstrate a series of responses involving different swimming patterns by changing flagellar beats, gradually approaching a swimming path toward the eggs, which is the source of chemoattractants. Shiba et al. observed a rapid increase in intracellular Ca2+ concentrations in Ciona spermatozoa after sensing chemoattractants; however, the biochemical processes occurring inside the sperm cells are unclear. In the present study, we focused on the timing and sensing mechanism of chemical signal detection in Ciona. One of the most crucial problems to be solved is defining the initial epoch of chemotactic responses. We adopted a high rate of video recording (600 Hz for detailed analysis of sperm motion and a novel method for detecting subtle signs of beat forms and moving paths of sperm heads. From these analyses, we estimated a virtual sensing point of the attractant before initiation of motility responses and found that the time delay from sensing to motility responses was almost constant. To evaluate the efficiency of this constant delay model, we performed computer simulation of chemotactic behaviors of Ciona spermatozoa.

  19. Chemotactic response with a constant delay-time mechanism in Ciona spermatozoa revealed by a high time resolution analysis of flagellar motility

    Science.gov (United States)

    Miyashiro, Daisuke; Shiba, Kogiku; Miyashita, Tahahiro; Baba, Shoji A.; Yoshida, Manabu; Kamimura, Shinji

    2015-01-01

    ABSTRACT During their chemotactic swimming toward eggs, sperm cells detect their species-specific chemoattractant and sense concentration gradients by unknown mechanisms. After sensing the attractant, sperm cells commonly demonstrate a series of responses involving different swimming patterns by changing flagellar beats, gradually approaching a swimming path toward the eggs, which is the source of chemoattractants. Shiba et al. observed a rapid increase in intracellular Ca2+ concentrations in Ciona spermatozoa after sensing chemoattractants; however, the biochemical processes occurring inside the sperm cells are unclear. In the present study, we focused on the timing and sensing mechanism of chemical signal detection in Ciona. One of the most crucial problems to be solved is defining the initial epoch of chemotactic responses. We adopted a high rate of video recording (600 Hz) for detailed analysis of sperm motion and a novel method for detecting subtle signs of beat forms and moving paths of sperm heads. From these analyses, we estimated a virtual sensing point of the attractant before initiation of motility responses and found that the time delay from sensing to motility responses was almost constant. To evaluate the efficiency of this constant delay model, we performed computer simulation of chemotactic behaviors of Ciona spermatozoa. PMID:25572419

  20. Chemotactic response with a constant delay-time mechanism in Ciona spermatozoa revealed by a high time resolution analysis of flagellar motility.

    Science.gov (United States)

    Miyashiro, Daisuke; Shiba, Kogiku; Miyashita, Tahahiro; Baba, Shoji A; Yoshida, Manabu; Kamimura, Shinji

    2015-01-08

    During their chemotactic swimming toward eggs, sperm cells detect their species-specific chemoattractant and sense concentration gradients by unknown mechanisms. After sensing the attractant, sperm cells commonly demonstrate a series of responses involving different swimming patterns by changing flagellar beats, gradually approaching a swimming path toward the eggs, which is the source of chemoattractants. Shiba et al. observed a rapid increase in intracellular Ca(2+) concentrations in Ciona spermatozoa after sensing chemoattractants; however, the biochemical processes occurring inside the sperm cells are unclear. In the present study, we focused on the timing and sensing mechanism of chemical signal detection in Ciona. One of the most crucial problems to be solved is defining the initial epoch of chemotactic responses. We adopted a high rate of video recording (600 Hz) for detailed analysis of sperm motion and a novel method for detecting subtle signs of beat forms and moving paths of sperm heads. From these analyses, we estimated a virtual sensing point of the attractant before initiation of motility responses and found that the time delay from sensing to motility responses was almost constant. To evaluate the efficiency of this constant delay model, we performed computer simulation of chemotactic behaviors of Ciona spermatozoa.

  1. Methods to eradicate soft tunic syndrome (STS-causing protozoa Azumiobodo hoyamushi, the highly infectious parasite from the edible ascidian (Halocynthia roretzi

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    Ji-Hoon Lee

    2016-03-01

    Full Text Available Abstract Although soft tunic syndrome (STS in the ascidian is a serious disease, helpful measures have yet not been established. It was examined in this study by applying aniti-parasitic drugs to eradicate the causative protozoa Azumiobodo hoyamushi from infected ascidians. Formalin was synergistic in killing parasites in vitro when co-treated with hydrogen peroxide (H2O2 or bronopol, but not with chloramine-T or povidone-iodine (PVP-I, when tested with in vitro parasite culture. The synergistic effects did not change when formalin-H2O2 (or bronopol ratios were changed. It was found that treatment periods less than 60 min achieved a sub-maximal efficacy. Increasing drug concentration while keeping 30 min period improved anti-parasitic effects. Anti-parasitic effects of formalin(F + H2O2(H were also assessed in an in vivo STS model infected with cultured parasites. It was observed that combined 50 (40F + 10H and 100 (80F +20H ppm were effective in partially preventing STS-caused mortality. In horizontally transmitted artificial STS model, significant prevention of ascidian mortality was also observed after 50 ppm. Marked reduction of living parasites were noted after drug treatments in vivo. The results provide a highly useful basis to develop a preventive or treatment measure against the currently uncontrollable STS in the ascidian.

  2. Deep sequencing of mixed total DNA without barcodes allows efficient assembly of highly plastic ascidian mitochondrial genomes.

    Science.gov (United States)

    Rubinstein, Nimrod D; Feldstein, Tamar; Shenkar, Noa; Botero-Castro, Fidel; Griggio, Francesca; Mastrototaro, Francesco; Delsuc, Frédéric; Douzery, Emmanuel J P; Gissi, Carmela; Huchon, Dorothée

    2013-01-01

    Ascidians or sea squirts form a diverse group within chordates, which includes a few thousand members of marine sessile filter-feeding animals. Their mitochondrial genomes are characterized by particularly high evolutionary rates and rampant gene rearrangements. This extreme variability complicates standard polymerase chain reaction (PCR) based techniques for molecular characterization studies, and consequently only a few complete Ascidian mitochondrial genome sequences are available. Using the standard PCR and Sanger sequencing approach, we produced the mitochondrial genome of Ascidiella aspersa only after a great effort. In contrast, we produced five additional mitogenomes (Botrylloides aff. leachii, Halocynthia spinosa, Polycarpa mytiligera, Pyura gangelion, and Rhodosoma turcicum) with a novel strategy, consisting in sequencing the pooled total DNA samples of these five species using one Illumina HiSeq 2000 flow cell lane. Each mitogenome was efficiently assembled in a single contig using de novo transcriptome assembly, as de novo genome assembly generally performed poorly for this task. Each of the new six mitogenomes presents a different and novel gene order, showing that no syntenic block has been conserved at the ordinal level (in Stolidobranchia and in Phlebobranchia). Phylogenetic analyses support the paraphyly of both Ascidiacea and Phlebobranchia, with Thaliacea nested inside Phlebobranchia, although the deepest nodes of the Phlebobranchia-Thaliacea clade are not well resolved. The strategy described here thus provides a cost-effective approach to obtain complete mitogenomes characterized by a highly plastic gene order and a fast nucleotide/amino acid substitution rate.

  3. Deep Sequencing of Mixed Total DNA without Barcodes Allows Efficient Assembly of Highly Plastic Ascidian Mitochondrial Genomes

    Science.gov (United States)

    Rubinstein, Nimrod D.; Feldstein, Tamar; Shenkar, Noa; Botero-Castro, Fidel; Griggio, Francesca; Mastrototaro, Francesco; Delsuc, Frédéric; Douzery, Emmanuel J.P.; Gissi, Carmela; Huchon, Dorothée

    2013-01-01

    Ascidians or sea squirts form a diverse group within chordates, which includes a few thousand members of marine sessile filter-feeding animals. Their mitochondrial genomes are characterized by particularly high evolutionary rates and rampant gene rearrangements. This extreme variability complicates standard polymerase chain reaction (PCR) based techniques for molecular characterization studies, and consequently only a few complete Ascidian mitochondrial genome sequences are available. Using the standard PCR and Sanger sequencing approach, we produced the mitochondrial genome of Ascidiella aspersa only after a great effort. In contrast, we produced five additional mitogenomes (Botrylloides aff. leachii, Halocynthia spinosa, Polycarpa mytiligera, Pyura gangelion, and Rhodosoma turcicum) with a novel strategy, consisting in sequencing the pooled total DNA samples of these five species using one Illumina HiSeq 2000 flow cell lane. Each mitogenome was efficiently assembled in a single contig using de novo transcriptome assembly, as de novo genome assembly generally performed poorly for this task. Each of the new six mitogenomes presents a different and novel gene order, showing that no syntenic block has been conserved at the ordinal level (in Stolidobranchia and in Phlebobranchia). Phylogenetic analyses support the paraphyly of both Ascidiacea and Phlebobranchia, with Thaliacea nested inside Phlebobranchia, although the deepest nodes of the Phlebobranchia–Thaliacea clade are not well resolved. The strategy described here thus provides a cost-effective approach to obtain complete mitogenomes characterized by a highly plastic gene order and a fast nucleotide/amino acid substitution rate. PMID:23709623

  4. Perforation with and without vinegar injection as a mitigation strategy against two invasive tunicates, Ciona intestinalis and Styela clava

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    Marianne PARENT

    2011-01-01

    Full Text Available Ciona intestinalis and Styela clava, two nuisance species for Prince Edward Island’s blue mussel industry, were treated with individual perforations using nails or hypodermic needles. Other treatments using the same species included simultaneous perforations using perforation devices with low, medium and high needle density, either with or without vinegar injections. Mortality levels estimated for all ranges of individual perforations were significantly higher than mortality levels estimated in control groups during treatments conducted at laboratory facilities. Mortality of C. intestinalis reached 100% for 60 individual perforations or injection of 0.05 mL of vinegar. In S. clava, 100 individual perforations resulted in 100% mortality. Two applications of the high-density perforation device resulted in 80% mortality of C. intestinalis. During field testing, two applications of the same high-density needle device did not significantly decrease C. intestinalis wet weight, regardless of the addition of vinegar. The field applicability of perforation upon tunicates fouling mussel socks was at least in part limited by the uneven surface created by the mussels and the possible inhibition of bacterial growth caused by low water temperatures. Perforation and vinegar injection showed to be successful in laboratory trials and should be further studied with different perforation devices under field conditions.

  5. Verruculides A and B, two new protein tyrosine phosphatase 1B inhibitors from an Indonesian ascidian-derived Penicillium verruculosum.

    Science.gov (United States)

    Yamazaki, Hiroyuki; Nakayama, Wataru; Takahashi, Ohgi; Kirikoshi, Ryota; Izumikawa, Yuta; Iwasaki, Kohei; Toraiwa, Kengo; Ukai, Kazuyo; Rotinsulu, Henki; Wewengkang, Defny S; Sumilat, Deiske A; Mangindaan, Remy E P; Namikoshi, Michio

    2015-08-15

    Two new merosesquiterpenes, verruculides A (1) and B (2), were isolated from a culture broth of the Indonesian ascidian-derived Penicillium verruculosum TPU1311, together with three known congeners, chrodrimanins A (3), B (4), and H (5). The structures of 1 and 2 were assigned on the basis of their spectroscopic data (1D and 2D NMR, HRMS, UV, CD, and IR). Compound 2 had a linear sesquiterpene moiety and was considered to be the derivative of the biosynthetic precursor for 1 and 3-5. Compounds 1, 3, and 5 inhibited the activity of protein tyrosine phosphatase 1B (PTP1B) with IC50 values of 8.4, 8.5, and 14.9 μM, respectively. Compound 2 showed 40% inhibition at 23.1 μM, while 4 was not active at 20.7 μM.

  6. Identification of Eusynstyelamide B as a Potent Cell Cycle Inhibitor Following the Generation and Screening of an Ascidian-Derived Extract Library Using a Real Time Cell Analyzer

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    Michelle S. Liberio

    2014-10-01

    Full Text Available Ascidians are marine invertebrates that have been a source of numerous cytotoxic compounds. Of the first six marine-derived drugs that made anticancer clinical trials, three originated from ascidian specimens. In order to identify new anti-neoplastic compounds, an ascidian extract library (143 samples was generated and screened in MDA-MB-231 breast cancer cells using a real-time cell analyzer (RTCA. This resulted in 143 time-dependent cell response profiles (TCRP, which are read-outs of changes to the growth rate, morphology, and adhesive characteristics of the cell culture. Twenty-one extracts affected the TCRP of MDA-MB-231 cells and were further investigated regarding toxicity and specificity, as well as their effects on cell morphology and cell cycle. The results of these studies were used to prioritize extracts for bioassay-guided fractionation, which led to the isolation of the previously identified marine natural product, eusynstyelamide B (1. This bis-indole alkaloid was shown to display an IC50 of 5 µM in MDA-MB-231 cells. Moreover, 1 caused a strong cell cycle arrest in G2/M and induced apoptosis after 72 h treatment, making this molecule an attractive candidate for further mechanism of action studies.

  7. Distinguishing contemporary hybridization from past introgression with postgenomic ancestry-informative SNPs in strongly differentiated Ciona species.

    Science.gov (United States)

    Bouchemousse, Sarah; Liautard-Haag, Cathy; Bierne, Nicolas; Viard, Frédérique

    2016-11-01

    Biological introductions bring into contact species that can still hybridize. The evolutionary outcomes of such secondary contacts may be diverse (e.g. adaptive introgression from or into the introduced species) but are not yet well examined in the wild. The recent secondary contact between the non-native sea squirt Ciona robusta (formerly known as C. intestinalis type A) and its native congener C. intestinalis (formerly known as C. intestinalis type B), in the Western English Channel, provides an excellent case study to examine. To examine contemporary hybridization between the two species, we developed a panel of 310 ancestry-informative SNPs from a population transcriptomic study. Hybridization rates were examined on 449 individuals sampled in eight sites from the sympatric range and five sites from allopatric ranges. The results clearly showed an almost complete absence of contemporary hybridization between the two species in syntopic localities, with only one-first-generation hybrid and no other genotype compatible with recent backcrosses. Despite the almost lack of contemporary hybridization, shared polymorphisms were observed in sympatric and allopatric populations of both species. Furthermore, one allopatric population from SE Pacific exhibited a higher rate of shared polymorphisms compared to all other C. robusta populations. Altogether, these results indicate that the observed level of shared polymorphism is more probably the outcome of ancient gene flow spread afterwards at a worldwide scale. They also emphasize efficient reproductive barriers preventing hybridization between introduced and native species, which suggests hybridization should not impede too much the expansion and the establishment of the non-native species in its introduction range.

  8. A forkhead gene related to HNF-3beta is required for gastrulation and axis formation in the ascidian embryo.

    Science.gov (United States)

    Olsen, C L; Jeffery, W R

    1997-09-01

    We have isolated a member of the HNF-3/forkhead gene family in ascidians as a means to determine the role of winged-helix genes in chordate development. The MocuFH1 gene, isolated from a Molgula oculata cDNA library, exhibits a forkhead DNA-binding domain most similar to zebrafish axial and rodent HNF-3beta. MocuFH1 is a single copy gene but there is at least one other related forkhead gene in the M. oculata genome. The MocuFH1 gene is expressed in the presumptive endoderm, mesenchyme and notochord cells beginning during the late cleavage stages. During gastrulation, MocuFH1 expression occurs in the prospective endoderm cells, which invaginate at the vegetal pole, and in the presumptive notochord and mesenchyme cells, which involute over the anterior and lateral lips of the blastopore, respectively. However, this gene is not expressed in the presumptive muscle cells, which involute over the posterior lip of the blastopore. MocuFH1 expression continues in the same cell lineages during neurulation and axis formation, however, during the tailbud stage, MocuFH1 is also expressed in ventral cells of the brain and spinal cord. The functional role of the MocuFH1 gene was studied using antisense oligodeoxynucleotides (ODNs), which transiently reduce MocuFH1 transcript levels during gastrulation. Embryos treated with antisense ODNs cleave normally and initiate gastrulation. However, gastrulation is incomplete, some of the endoderm and notochord cells do not enter the embryo and undergo subsequent movements, and axis formation is abnormal. In contrast, the prospective muscle cells, which do not express MocuFH1, undergo involution and later express muscle actin and acetylcholinesterase, markers of muscle cell differentiation. The results suggest that MocuFH1 is required for morphogenetic movements of the endoderm and notochord precursor cells during gastrulation and axis formation. The effects of inhibiting MocuFH1 expression on embryonic axis formation in ascidians are

  9. A statistical approach for optimization of alkaline lipase production by ascidian associated—Halobacillus trueperi RSK CAS9

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    Ramamoorthy Sathishkumar

    2015-12-01

    Full Text Available A marine ascidian-associated bacterium, Halobacillus trueperi RSK CAS9, was optimized for lipase production by response surface methodology using marine waste as substrate. The central composite design was employed, and the optimal medium constituents for maximum lipase production (1355.81 U/ml were determined to be tuna powder (14.58 g/l, olive oil (5.05 ml/l; NaCl (72.42 g/l, temperature (45 °C and pH 9.0. An alkaline lipase was purified to 8.46 fold with 1193.59 U mg−1 specific activities with the molecular weight of 44 kDa. The activity was substantially inhibited by EDTA and PMSF, indicating that it was a metalloenzyme serine residue which was essential for catalytic activity. Thus, lipase production by microbial conversion of marine fish wastes in this study suggested its potential utilization for the production of high value products.

  10. Cytotoxicity of actinomycetes associated with the ascidian Eudistoma vannamei (Millar, 1977, endemic of northeastern coast of Brazil

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    Paula C Jimenez

    2013-04-01

    Full Text Available Previous studies demonstrated that the crude extract of the ascidian Eudistoma vannamei, endemic from northeasttern Brazil, strongly hinders growth of tumor cells in vitro by inducing apoptosis due to tryptophan derivatives, which are commonly found in bacteria. This study presents a bioactivity-guided screening among actinomycetes, associated with E. vannamei, aiming at recognizing active principles with biological relevance. Twenty strains of actinomycetes, designated as EVA 0101 through 0120, were isolated from colonies of E. vannamei among which 11 were selected for cytotoxicity evaluation. The extracts from EVA 0102, 0103, 0106, 0109 and 0113 were the most active, and were further studied for IC50 determination and chemical analysis by ¹H NMR. IC50 values obtained ranged from 3.62 µg mL-1 (for EVA 0109 in leukemia cells to 84.65 µg/mL (for EVA 0106 in melanoma cells. All active extracts exhibited the same TLC and spectroscopic profiles, suggesting the presence of quinones and other related secondary metabolites. Furthermore, these strains were identified and compared based on their respective 16S rRNA sequences. The results herein identified the five strains as Micromonospora spp. while phylogenetic analysis suggests that they are possibly two different Micromonospora species producing the cytotoxic compounds.

  11. From tropical to sub-tropical: Prolonged reproductive activity of the invasive ascidian Microcosmus exasperatus in the eastern Mediterranean

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    Lilach Raijman Nagar

    2016-08-01

    Full Text Available The solitary ascidian Microcosmus exasperatus is globally distributed in tropical and sub-tropical waters. In the Mediterranean it is considered an invasive species introduced through the Suez Canal, with a restricted distribution in the eastern basin. In order to understand the potential of this species to establish sustainable communities at additional sites in the Mediterranean, we studied its reproduction cycle over a 2-year period in relation to seawater temperature and chlorophyll-a data. Although M. exasperatus reproduces seasonally, with significantly greater activity in summer and early fall, mature oocytes occur throughout the year, suggesting multiple spawning periods. We found that reproductive effort significantly correlated with seawater temperature, while chlorophyll-a showed a low and insignificant explanatory power. A combined regression model of both parameters yielded the highest explained variance, suggesting a synergic effect of these two factors. Such a prolonged reproductive activity period enables repeated recruitment events. In view of the anticipated rise in seawater temperature, we predict that this species will gradually expand its distribution further across the Mediterranean.

  12. T-type Ca2+ current activity during oocyte growth and maturation in the ascidian Styela plicata.

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    Alessandra Gallo

    Full Text Available Voltage-dependent calcium currents play a fundamental role during oocyte maturation, mostly L-type calcium currents, whereas T-type calcium currents are involved in sperm physiology and cell growth. In this paper, using an electrophysiological and pharmacological approach, we demonstrated, for the first time in oocytes, that T-type calcium currents are present with functional consequences on the plasma membrane of growing immature oocytes of the ascidian Styela plicata. We classified three subtypes of immature oocytes at the germinal vesicle stage on the basis of their size, morphology and accessory cellular structures. These stages were clearly associated with an increased activity of T-type calcium currents and hyperpolarization of the plasma membrane. We also observed that T-type calcium currents oscillate in the post-fertilization embryonic stages, with minimal amplitude of the currents in the zygote and maximal at 8-cell stage. In addition, chemical inhibition of T-type calcium currents, obtained by applying specific antagonists, induced a significant reduction in the rate of cleavage and absence of larval formation. We suggest that calcium entry via T-type calcium channels may act as a potential pacemaker in regulating cytosolic calcium involved in fertilization and early developmental events.

  13. NK4 antagonizes Tbx1/10 to promote cardiac versus pharyngeal muscle fate in the ascidian second heart field.

    Science.gov (United States)

    Wang, Wei; Razy-Krajka, Florian; Siu, Eric; Ketcham, Alexandra; Christiaen, Lionel

    2013-12-01

    The heart and head muscles share common developmental origins and genetic underpinnings in vertebrates, including humans. Parts of the heart and cranio-facial musculature derive from common mesodermal progenitors that express NKX2-5, ISL1, and TBX1. This ontogenetic kinship is dramatically reflected in the DiGeorge/Cardio-Velo-Facial syndrome (DGS/CVFS), where mutations of TBX1 cause malformations in the pharyngeal apparatus and cardiac outflow tract. Cardiac progenitors of the first heart field (FHF) do not require TBX1 and segregate precociously from common progenitors of the second heart field (SHF) and pharyngeal muscles. However, the cellular and molecular mechanisms that govern heart versus pharyngeal muscle specification within this lineage remain elusive. Here, we harness the simplicity of the ascidian larva to show that, following asymmetric cell division of common progenitors, NK4/NKX2-5 promotes GATAa/GATA4/5/6 expression and cardiac specification in the second heart precursors by antagonizing Tbx1/10-mediated inhibition of GATAa and activation of Collier/Olf/EBF (COE), the determinant of atrial siphon muscle (ASM) specification. Our results uncover essential regulatory connections between the conserved cardio-pharyngeal factor Tbx1/10 and muscle determinant COE, as well as a mutual antagonism between NK4 and Tbx1/10 activities upstream of GATAa and COE. The latter cross-antagonism underlies a fundamental heart versus pharyngeal muscle fate choice that occurs in a conserved lineage of cardio-pharyngeal progenitors. We propose that this basic ontogenetic motif underlies cardiac and pharyngeal muscle development and evolution in chordates.

  14. NK4 antagonizes Tbx1/10 to promote cardiac versus pharyngeal muscle fate in the ascidian second heart field.

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    Wei Wang

    2013-12-01

    Full Text Available The heart and head muscles share common developmental origins and genetic underpinnings in vertebrates, including humans. Parts of the heart and cranio-facial musculature derive from common mesodermal progenitors that express NKX2-5, ISL1, and TBX1. This ontogenetic kinship is dramatically reflected in the DiGeorge/Cardio-Velo-Facial syndrome (DGS/CVFS, where mutations of TBX1 cause malformations in the pharyngeal apparatus and cardiac outflow tract. Cardiac progenitors of the first heart field (FHF do not require TBX1 and segregate precociously from common progenitors of the second heart field (SHF and pharyngeal muscles. However, the cellular and molecular mechanisms that govern heart versus pharyngeal muscle specification within this lineage remain elusive. Here, we harness the simplicity of the ascidian larva to show that, following asymmetric cell division of common progenitors, NK4/NKX2-5 promotes GATAa/GATA4/5/6 expression and cardiac specification in the second heart precursors by antagonizing Tbx1/10-mediated inhibition of GATAa and activation of Collier/Olf/EBF (COE, the determinant of atrial siphon muscle (ASM specification. Our results uncover essential regulatory connections between the conserved cardio-pharyngeal factor Tbx1/10 and muscle determinant COE, as well as a mutual antagonism between NK4 and Tbx1/10 activities upstream of GATAa and COE. The latter cross-antagonism underlies a fundamental heart versus pharyngeal muscle fate choice that occurs in a conserved lineage of cardio-pharyngeal progenitors. We propose that this basic ontogenetic motif underlies cardiac and pharyngeal muscle development and evolution in chordates.

  15. Suppression of cell-spreading and phagocytic activity on nano-pillared surface: in vitro experiment using hemocytes of the colonial ascidian Botryllus schlosseri

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    L Ballarin

    2015-02-01

    Full Text Available Nano-scale nipple array on the body surface has been described from various invertebrates including endoparasitic and mesoparasitic copepods, but the functions of the nipple array is not well understood. Using the hydrophilized nanopillar sheets made of polystyrene as a mimetic material of the nipple arrays on the parasites’ body surface, we assayed the cell spreading and phagocytosis of the hemocytes of the colonial ascidian Botryllus schlosseri. On the pillared surface, the number of spreading amebocytes and the number of phagocytizing hemocytes per unit area were always smaller than those on the flat surface (Mann-Whitney test, p < 0.05 - 0.001, probably because the effective area for the cell attachment on the pillared surface is much smaller than the area on the flat sheet. The present results supports the idea that the nipple array on the parasites' body surface reduces the innate immune reaction from the host hemocytes.

  16. CS5931, a Novel Polypeptide in Ciona savignyi, Represses Angiogenesis via Inhibiting Vascular Endothelial Growth Factor (VEGF and Matrix Metalloproteinases (MMPs

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    Ge Liu

    2014-03-01

    Full Text Available CS5931 is a novel polypeptide from Ciona savignyi with anticancer activities. Previous study in our laboratory has shown that CS5931 can induce cell death via mitochondrial apoptotic pathway. In the present study, we found that the polypeptide could inhibit angiogenesis both in vitro and in vivo. CS5931 inhibited the proliferation, migration and formation of capillary-like structures of HUVECs (Human Umbilical Vein Endothelial Cell in a dose-dependent manner. Additionally, CS5931 repressed spontaneous angiogenesis of the zebrafish vessels. Further studies showed that CS5931 also blocked vascular endothelial growth factor (VEGF production but without any effect on its mRNA expression. Moreover, CS5931 reduced the expression of matrix metalloproteinases (MMP-2 and MMP-9 both on protein and mRNA levels in HUVEC cells. We demonstrated that CS5931 possessed strong anti-angiogenic activity both in vitro and in vivo, possible via VEGF and MMPs. This study indicates that CS5931 has the potential to be developed as a novel therapeutic agent as an inhibitor of angiogenesis for the treatment of cancer.

  17. A Boolean Function for Neural Induction Reveals a Critical Role of Direct Intercellular Interactions in Patterning the Ectoderm of the Ascidian Embryo.

    Science.gov (United States)

    Ohta, Naoyuki; Waki, Kana; Mochizuki, Atsushi; Satou, Yutaka

    2015-12-01

    A complex system of multiple signaling molecules often produce differential gene expression patterns in animal embryos. In the ascidian embryo, four signaling ligands, Ephrin-A.d (Efna.d), Fgf9/16/20, Admp, and Gdf1/3-r, coordinately induce Otx expression in the neural lineage at the 32-cell stage. However, it has not been determined whether differential inputs of all of these signaling pathways are really necessary. It is possible that differential activation of one of these signaling pathways is sufficient and the remaining signaling pathways are activated in all cells at similar levels. To address this question, we developed a parameter-free method for determining a Boolean function for Otx expression in the present study. We treated activities of signaling pathways as Boolean values, and we also took all possible patterns of signaling gradients into consideration. We successfully determined a Boolean function that explains Otx expression in the animal hemisphere of wild-type and morphant embryos at the 32-cell stage. This Boolean function was not inconsistent with three sensing patterns, which represented whether or not individual cells received sufficient amounts of the signaling molecules. These sensing patterns all indicated that differential expression of Otx in the neural lineage is primarily determined by Efna.d, but not by differential inputs of Fgf9/16/20, Admp, and Gdf1/3-r signaling. To confirm this hypothesis experimentally, we simultaneously knocked-down Admp, Gdf1/3-r, and Fgf9/16/20, and treated this triple morphant with recombinant bFGF and BMP4 proteins, which mimic Fgf9/16/20 and Admp/Gdf1/3-r activity, respectively. Although no differential inputs of Admp, Gdf1/3-r and Fgf9/16/20 signaling were expected under this experimental condition, Otx was expressed specifically in the neural lineage. Thus, direct cell-cell interactions through Efna.d play a critical role in patterning the ectoderm of the early ascidian embryo.

  18. Combining environmental suitability and population abundances to evaluate the invasive potential of the tunicate Ciona intestinalis along the temperate South American coast

    Directory of Open Access Journals (Sweden)

    Stella M. Januario

    2015-10-01

    Full Text Available The tunicate Ciona intestinalis is an opportunistic invader with high potential for causing economic losses in aquaculture centers. Recent phylogenetic and population genetic analysis support the existence of a genetic complex described as C. intestinalis with two main dominant species (sp A and B occurring worldwide. In Chile, the species has been observed around 30°S of latitude, but no official reports exist for the presence of C. intestinalis in southern regions (above 40°S, where most of the mollusk aquaculture centers are located. Here, we used occurrences from multiple invaded regions and extensive field sampling to model and validate the environmental conditions that allow the species to persist and to find the geographic areas with the most suitable environmental conditions for the spread of C. intestinalis in the Chilean coast. By studying the potential expansion of C. intestinalis southward in the Chilean Coast, we aimed to provide valuable information that might help the development of control plans before the species becomes a significant problem, especially above 40°S. Our results highlight that, by using portions of the habitat that are apparently distinguishable, the species seem to be not only genetically distinct, but ecologically distinct as well. The two regional models fitted for sp A and for sp B showed disagreement on which sections of Chilean coastline are considered more suitable for these species. While the model for sp A identifies moderately to highly suitable areas between 30° and 40°S, the model for sp B classifies the areas around 45°S as the most appropriate. Data from field sampling show a positive linear relationship between density of C. intestinalis and the index of suitability for sp A in aquaculture centers. Understanding the relation of the distinct species with the surrounding environment provided valuable insights about probable routes of dispersion in Chile, especially into those areas considered

  19. Follicle cell trypsin-like protease HrOvochymase: Its cDNA cloning, localization, and involvement in the late stage of oogenesis in the ascidian Halocynthia roretzi.

    Science.gov (United States)

    Mino, Masako; Sawada, Hitoshi

    2016-04-01

    We previously reported that the sperm trypsin-like protease HrAcrosin and its precursor HrProacrosin participate in fertilization of the ascidian Halocynthia roretzi. The HrProacrosin gene is annotated in the H. roretzi genome database as Harore.CG.MTP2014.S89.g15383; our previously reported sequence of HrProacrosin gene appeared to include four nucleotides inserted near the 3'-end of HrProacrosin, resulting in a frame-shift mutation and a premature termination codon. The gene architecture of HrProacrosin and Harore.CG.MTP2014.S89.g15383 resembles that of Xenopus laevis ovochymase-1/OVCH1 and ovochymase-2/OVCH2, which encode egg extracellular polyproteases. Considering these new observations, we evaluated the cDNA cloning, expression, localization, and function of Harore.CG.MTP2014.S89.g15383, herein designated as HrOvochymase/HrOVCH. We found that HrOVCH cDNA consists of a single open reading frame of 1,575 amino acids, containing a signal peptide, three trypsin-like protease domains, and six CUB domains. HrOVCH was transcribed by the testis and ovary, but the majority of protein exists in ovarian follicle cells surrounding eggs. An anti-HrOVCH antibody inhibited elevation of the vitelline coat at a late stage of oogenesis, during the period when self-sterility is acquired. As trypsin inhibitors are reported to block the acquisition of self-sterility during oogenesis, whereas trypsin induces the acquisition of self-sterility and elevation of the vitelline coat in defolliculated ovarian eggs, we propose that HrOVCH may play a role in the acquisition of self-sterility by late-stage H. roretzi oocytes.

  20. The colonial ascidian Didemnum sp. A: current distribution, basic biology and potential threat to marine communities of the northeast and west coasts of North America

    Science.gov (United States)

    Bullard, S.G.; Lambert, G.; Carman, M.R.; Byrnes, J.; Whitlatch, R.B.; Ruiz, G.; Miller, R.J.; Harris, L.; Valentine, P.C.; Collie, J.S.; Pederson, J.; McNaught, D.C.; Cohen, A.N.; Asch, R.G.; Dijkstra, J.; Heinonen, K.

    2007-01-01

    Didemnum sp. A is a colonial ascidian with rapidly expanding populations on the east and west coasts of North America. The origin of Didemum sp. A is unknown. Populations were first observed on the northeast coast of the U.S. in the late 1980s and on the west coast during the 1990s. It is currently undergoing a massive population explosion and is now a dominant member of many subtidal communities on both coasts. To determine Didemnum sp. A's current distribution, we conducted surveys from Maine to Virginia on the east coast and from British Columbia to southern California on the west coast of the U.S. between 1998 and 2005. In nearshore locations Didemnum sp. A currently ranges from Eastport, Maine to Shinnecock Bay, New York on the east coast. On the west coast it has been recorded from Humboldt Bay to Port San Luis in California, several sites in Puget Sound, Washington, including a heavily fouled mussel culture facility, and several sites in southwestern British Columbia on and adjacent to oyster and mussel farms. The species also occurs at deeper subtidal sites (up to 81 m) off New England, including Georges, Stellwagen and Tillies Banks. On Georges Bank numerous sites within a 230 km2 area are 50–90% covered by Didemnum sp. A; large colonies cement the pebble gravel into nearly solid mats that may smother infaunal organisms. These observations suggest that Didemnum sp. A has the potential to alter marine communities and affect economically important activities such as fishing and aquaculture.

  1. The occurrence of the colonial ascidian Didemnum sp. on Georges Bank gravel habitat: ecological observations and potential effects on groundfish and scallop fisheries

    Science.gov (United States)

    Valentine, P.C.; Collie, J.S.; Reid, R.N.; Asch, R.G.; Guida, V.G.; Blackwood, D.S.

    2007-01-01

    The colonial ascidian Didemnum sp. is present on the Georges Bank fishing grounds in a gravel habitat where the benthic invertebrate fauna has been monitored annually since 1994. The species was not noted before 2002 when large colonies were first observed; and by 2003 and 2004 it covered large areas of the seabed at some locations. The latest survey in 2005 documented the tunicate's presence in two gravel areas that total more than 67 nm2 (230 km2). The affected area is located on the Northern Edge of the bank in United States waters near the U.S./Canada boundary ( Fig. 1). This is the first documented offshore occurrence of a species that has colonized eastern U.S. coastal waters from New York to Maine during the past 15–20 years ( U.S. Geological Survey, 2006). Video imagery shows colonies coalescing to form large mats that cover more than 50% of the seabed along some video/photo transects. The affected area is an immobile pebble and cobble pavement that lies at water depths of 40 to 65 m where strong semidiurnal tidal currents reach speeds of 1 to 2 kt (50–100 cm/s). The water column is mixed year round, ensuring a constant supply of nutrients to the seabed. Annual temperatures range from 4 to 15 °C ( Mountain and Holzwarth, 1989). The gravel areas are bounded by sand ridges whose mobile surfaces are moved daily by the strong tidal currents. Studies commenced here in 1994 to characterize the gravel habitat and to document the effects of fishing disturbance on it ( Collie et al., 2005).

  2. Variation in the composition of corals, fishes, sponges, echinoderms, ascidians, molluscs, foraminifera and macroalgae across a pronounced in-to-offshore environmental gradient in the Jakarta Bay-Thousand Islands coral reef complex.

    Science.gov (United States)

    Cleary, D F R; Polónia, A R M; Renema, W; Hoeksema, B W; Rachello-Dolmen, P G; Moolenbeek, R G; Budiyanto, A; Yahmantoro; Tuti, Y; Giyanto; Draisma, S G A; Prud'homme van Reine, W F; Hariyanto, R; Gittenberger, A; Rikoh, M S; de Voogd, N J

    2016-09-30

    Substrate cover, water quality parameters and assemblages of corals, fishes, sponges, echinoderms, ascidians, molluscs, benthic foraminifera and macroalgae were sampled across a pronounced environmental gradient in the Jakarta Bay-Thousand Islands reef complex. Inshore sites mainly consisted of sand, rubble and turf algae with elevated temperature, dissolved oxygen, pH and chlorophyll concentrations and depauperate assemblages of all taxa. Live coral cover was very low inshore and mainly consisted of sparse massive coral heads and a few encrusting species. Faunal assemblages were more speciose and compositionally distinct mid- and offshore compared to inshore. There were, however, small-scale differences among taxa. Certain midshore sites, for example, housed assemblages resembling those typical of the inshore environment but this differed depending on the taxon. Substrate, water quality and spatial variables together explained from 31% (molluscs) to 72% (foraminifera) of the variation in composition. In general, satellite-derived parameters outperformed locally measured parameters.

  3. Endozoicomonas Are Specific, Facultative Symbionts of Sea Squirts

    Science.gov (United States)

    Schreiber, Lars; Kjeldsen, Kasper U.; Funch, Peter; Jensen, Jeppe; Obst, Matthias; López-Legentil, Susanna; Schramm, Andreas

    2016-01-01

    Ascidians are marine filter feeders and harbor diverse microbiota that can exhibit a high degree of host-specificity. Pharyngeal samples of Scandinavian and Mediterranean ascidians were screened for consistently associated bacteria by culture-dependent and -independent approaches. Representatives of the Endozoicomonas (Gammaproteobacteria, Hahellaceae) clade were detected in the ascidian species Ascidiella aspersa, Ascidiella scabra, Botryllus schlosseri, Ciona intestinalis, Styela clava, and multiple Ascidia/Ascidiella spp. In total, Endozoicomonas was detected in more than half of all specimens screened, and in 25–100% of the specimens for each species. The retrieved Endozoicomonas 16S rRNA gene sequences formed an ascidian-specific subclade, whose members were detected by fluorescence in situ hybridization (FISH) as extracellular microcolonies in the pharynx. Two strains of the ascidian-specific Endozoicomonas subclade were isolated in pure culture and characterized. Both strains are chemoorganoheterotrophs and grow on mucin (a mucus glycoprotein). The strains tested negative for cytotoxic or antibacterial activity. Based on these observations, we propose ascidian-associated Endozoicomonas to be commensals, living off the mucus continuously secreted into the pharynx. Members of the ascidian-specific Endozoicomonas subclade were also detected in seawater from the Scandinavian sampling site, which suggests acquisition of the symbionts by horizontal transmission. The combined results indicate a host-specific, yet facultative symbiosis between ascidians and Endozoicomonas. PMID:27462299

  4. 薄荷醇麻醉剥离参苗与玻璃海鞘分离的研究%Detaching effect of menthol on the attachment of sea cucumber (Apostichopus japonicus) apart from sea squirt (Ciona intes-tinalis)

    Institute of Scientific and Technical Information of China (English)

    张艳萍; 韩莎; 李成林; 赵斌; 胡炜

    2016-01-01

    在刺参苗种工厂化生产期间,以体积浓度为0.1%~0.5%薄荷醇作为麻醉剂,通过对玻璃海鞘和不同规格参苗进行麻醉剥离实验,研究参苗与敌害生物——玻璃海鞘分离的效果,从而达到高效清除玻璃海鞘的目的。结果表明:薄荷醇溶液对玻璃海鞘无剥离和杀除的作用效果;大规格(0.58 g±0.05 g)刺参选用浓度0.4%~0.5%薄荷醇溶液麻醉20 min,中规格(0.32 g±0.05 g)刺参选用浓度0.2%~0.5%薄荷醇溶液麻醉20min,小规格(0.17 g±0.01 g)刺参选用浓度0.4%~0.5%薄荷醇溶液麻醉10min以及选用浓度0.1%~0.3%薄荷醇溶液麻醉20 min,抖动脱落率均可达90%以上,麻醉剥离效果显著。麻醉剥离后的刺参经1h 的恢复即可达到自然状态,营正常活动附着,无排脏或化皮等不良应激反应。因此,采用薄荷醇麻醉剥离参苗可为安全高效清除玻璃海鞘及分苗的生产环节提供省工省力、高效便捷的方法。%This study aims to develop an efficient method for removing sea squirtCiona intestinalisfrom the sea cucumber nursery system. The detaching effects of menthol (0.1%~0.5% in volume) on the attachment of sea squirt C. intestinalis and different-sized sea cucumber (Apostichopus japonicus) were tested. The results showed that menthol was ineffective in killing or detachingC. intestinalisfrom the attachment. The detaching effect of menthol on different-sized sea cucumbers significantly differed. Over 90% of detachment shaking from settlement substrate was found in the large-sized (0.58 g ± 0.05 g) juveniles exposed to 0.4%~0.5% of menthol for 20 min, me-dium-sized (0.32 g ± 0.05 g) juveniles exposed to 0.2%~0.5% of menthol for 20 min, and small-sized (0.17 g ± 0.01g) exposed to 0.4%~0.5% of menthol for 10 min or exposed to 0.1%~0.3% of menthol for 20 min. These juve-niles, after being detached from the attachment, recovered to reattach after 1 h without ulceration and evisceration. Therefore, this method is

  5. Isolation and biological activities of secondary metabolites from the sponges monanchora aff. arbuscula, aplysina sp. petromica ciocalyptoides and topsentia ophiraphidies, from the ascidian didemnum ligulum and from the octocoral carijoa riisei; Isolamento e atividades biologicas de produtos naturais das esponjas monanchora arbuscula, aplysina sp., petromica ciocalyptoides e topsentia ophiraphidites, da ascidia didemnum ligulum e do octocoral carijoa riisei

    Energy Technology Data Exchange (ETDEWEB)

    Kossuga, Miriam H.; Lira, Simone P. de; Nascimento, Andrea M.; Gambardella, Maria Teresa P.; Berlinck, Roberto G.S. [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Inst. de Quimica]. E-mail: rgsberlinck@iqsc.usp.br; Torres, Yohandra R. [Universidade Estadual do Centro-Oeste, Guarapuava, PR (Brazil). Dept. de Quimica; Nascimento, Gislene G.F. [Universidade Metodista de Piracicaba (UNIMEP), SP (Brazil). Faculdade de Ciencias da Saude; Pimenta, Eli F.; Silva, Marcio; Thiemann, Otavio H.; Oliva, Glaucius [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Inst. de Fisica; Tempone, Andre G.; Melhem, Marcia S.C. [Instituto Adolfo Lutz, Sao Paulo, SP (Brazil). Div. de Biologia Medica; Souza, Ana O. de; Galetti, Fabio C.S.; Silva, Celio L. [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Dept. de Bioquimica e Imunologia; Cavalcanti, Bruno; Pessoa, Claudia O.; Moraes, Manoel O. [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Faculdade de Medicina. Dept. de Fisiologia e Farmacologia; Hajdu, Eduardo [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Museu Nacional; Peixinho, Solange [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Dept. de Biologia; Rocha, Rosana M. [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Setor de Ciencias Biologicas. Dept. de Zoologia

    2007-09-15

    The investigation of extracts from six species of marine invertebrates yielded one new and several known natural products. Isoptilocaulin from the sponge Monanchora aff. arbuscula displayed antimicrobial activity at 1.3 mg/mL against an oxacillin-resistant strain of Staphylococcus aureus. Five inactive known dibromotyrosine derivatives, 2 6, were isolated from a new species of marine sponge, Aplysina sp. The sponges Petromica ciocalyptoides and Topsentia ophiraphidites yielded the known halistanol sulfate A (7) as an inhibitor of the antileishmanial target adenosine phosphoribosyl transferase. The ascidian Didemnum ligulum yielded asterubin (10) and the new N,N-dimethyl-O-methylethanolamine (11). The octocoral Carijoa riisei yielded the known 18-acetoxypregna-1,4,20-trien-3-one (12), which displayed cytotoxic activity against the cancer cell lines SF295, MDA-MB435, HCT8 and HL60. (author)

  6. ACAM, a novel member of the neural IgCAM family, mediates anterior neural tube closure in a primitive chordate.

    Science.gov (United States)

    Morales Diaz, Heidi; Mejares, Emil; Newman-Smith, Erin; Smith, William C

    2016-01-01

    The neural IgCAM family of cell adhesion molecules, which includes NCAM and related molecules, has evolved via gene duplication and alternative splicing to allow for a wide range of isoforms with distinct functions and homophilic binding properties. A search for neural IgCAMs in ascidians (Ciona intestinalis, Ciona savignyi, and Phallusia mammillata) has identified a novel set of truncated family members that, unlike the known members, lack fibronectin III domains and consist of only repeated Ig domains. Within the tunicates this form appears to be unique to the ascidians, and it was designated ACAM, for Ascidian Cell Adhesion Molecule. In C. intestinalis ACAM is expressed in the developing neural plate and neural tube, with strongest expression in the anterior sensory vesicle precursor. Unlike the two other conventional neural IgCAMs in C. intestinalis, which are expressed maternally and throughout the morula and blastula stages, ACAM expression initiates at the gastrula stage. Moreover, C. intestinalis ACAM is a target of the homeodomain transcription factor OTX, which plays an essential role in the development of the anterior central nervous system. Morpholino (MO) knockdown shows that ACAM is required for neural tube closure. In MO-injected embryos neural tube closure was normal caudally, but the anterior neuropore remained open. A similar phenotype was seen with overexpression of a secreted version of ACAM. The presence of ACAM in ascidians highlights the diversity of this gene family in morphogenesis and neurodevelopment.

  7. Protein hydrolysates produced from rock lobster (Jasus edwardsii) Head: emulsifying capacity and food safety.

    Science.gov (United States)

    He, Shan; Nguyen, Trung T; Su, Peng; Zhang, Wei

    2016-11-01

    Lobster protein hydrolysates (LPH) were produced by an enzymatic process using a proteinase Alcalase, and a chemical process at strong alkaline condition (pH of 14), from rock lobster head (RLH), respectively. The chemical process recovered about 30% more protein than the enzymatic process (84.9% recovery of total protein in RLH by the chemical process and 54.5% recovery of total protein in RLH by the enzymatic process). The emulsifying capacity of LPH produced by the chemical process (69.7 m(2)/g) was significantly higher than the emulsifying capacity of the LPH produced by the enzymatic process (20.7 m(2)/g), and also exceeds the emulsifying capacity of cow gelatine (50.3 m(2)/g), a commercial emulsifier in the food industry. LPH produced by the chemical process possess 30.3% essential amino acids. This content is comparable with the essential amino acid content of fish protein, a commonly recognized food resource for essential amino acid supplement for human. The content of heavy metals, including inorganic arsenic, of LPH is lower than the standard levels regulated by Food Standard Australia and New Zealand (FSANZ). These results demonstrated the potential value of LPH used as a safe emulsifier with significant nutritional value for the food industry.

  8. Natural products from the ascidian Botrylloides giganteum, from the sponges Verongula gigantea, Ircinia felix, Cliona delitrix and from the nudibranch Tambja eliora, from the Brazilian coastline; Produtos naturais da ascidia Botrylloides giganteum, das esponjas Verongula gigantea, Ircinia felix, Cliona delitrix e do nudibranquio Tambja eliora, da costa do Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Granato, Ana Claudia; Oliveira, Jaine H.H.L. de; Seleghim, Mirna H.R.; Berlinck, Roberto G.S. [Sao Paulo Univ., Sao Carlos, SP (Brazil). Inst. de Quimica]. E-mail: rgsberlinck@iqsc.usp.br; Macedo, Mario L.; Ferreira, Antonio G. [Sao Carlos Univ., SP (Brazil). Dept. de Quimica; Rocha, Rosana M. da [Parana Univ., Curitiba, PR (Brazil). Setor de Ciencias Biologicas. Dept. de Zoologia; Hajdu, Eduardo [Universidade Federal, Rio de Janeiro, RJ (Brazil). Museu Nacional; Peixinho, Solange [Bahia Univ., Salvador, BA (Brazil). Dept. de Biologia; Pessoa, Claudia O.; Moraes, Manoel O.; Cavalcanti, Bruno C. [Ceara Univ., Fortaleza, CE (Brazil). Dept. de Fisiologia e Farmacologia

    2005-04-01

    Two new marine metabolites, 3Z, 6Z, 9Z-dodecatrien-1-ol (1) from the ascidian Botrylloides giganteum and 4H-pyran-2ol acetate from the sponge Ircinia felix (4) are herein reported. The known bromotyrosine compounds, 2-(3,5-dibromo-4-methoxyphenyl)-N,N,Ndimethylethanammonium (2) and 2,6-dibromo-4-(2-(trimethylammonium)ethyl)phenol (3), have been isolated from the sponge Verongula gigantea. Serotonin (5) is reported for the first time from the sponge Cliona delitrix, and tambjamines A (15) and D (16) isolated as their respective salts from the nudibranch Tambja eliora. Only tambjamine D presented cytotoxicity against CEM (IC{sub 5})0 12.2 {mu}g/mL) and HL60 (IC{sub 50} 13.2 {mu}g/mL) human leukemia cells, MCF-7 breast cancer cells (IC{sub 50} 13.2 {mu}g/mL), colon HCT-8 cancer cells (IC{sub 50} 10.1 {mu}g/mL) and murine melanoma B16 cancer cells (IC{sub 50} 6.7 {mu}g/mL). (author)

  9. Produtos naturais da ascídia Botrylloides giganteum, das esponjas Verongula gigantea, Ircinia felix, Cliona delitrix e do nudibrânquio Tambja eliora, da costa do Brasil Natural products from the ascidian Botrylloides giganteum, from the sponges Verongula gigantea, Ircinia felix, Cliona delitrix and from the nudibranch Tambja eliora, from the Brazilian coastline

    Directory of Open Access Journals (Sweden)

    Ana Claudia Granato

    2005-03-01

    Full Text Available Two new marine metabolites, 3Z, 6Z, 9Z-dodecatrien-1-ol (1 from the ascidian Botrylloides giganteum and 4H-pyran-2ol acetate from the sponge Ircinia felix (4 are herein reported. The known bromotyrosine compounds, 2-(3,5-dibromo-4-methoxyphenyl-N,N,N-dimethylethanammonium (2 and 2,6-dibromo-4-(2-(trimethylammoniumethylphenol (3, have been isolated from the sponge Verongula gigantea. Serotonin (5 is reported for the first time from the sponge Cliona delitrix, and tambjamines A (15 and D (16 isolated as their respective salts from the nudibranch Tambja eliora. Only tambjamine D presented cytotoxicity against CEM (IC50 12.2 µg/mL and HL60 (IC50 13.2 µg/mL human leukemya cells, MCF-7 breast cancer cells (IC50 13.2 µg/mL, colon HCT-8 cancer cells (IC50 10.1 µg/mL and murine melanoma B16 cancer cells (IC50 6.7 µg/mL.

  10. Recruitment and colonization of colonial ascidians (Tunicata: Ascidiacea on intertidal rocks in Northeastern Brazil Recrutamento e colonização de ascídias coloniais (Tunicata: Ascidiacea em rochas de entre-marés no nordeste do Brasil

    Directory of Open Access Journals (Sweden)

    Petrônio Bezerra Gama

    2006-06-01

    Full Text Available Recruitment and colonization of colonial ascidians, starting on natural scraped substratum, was observed throughout one year, in quadrats marked on sea- and continental-rock faces in the sublittoral fringe of an exposed beach in the Northeast of Brazil. The species of the Didemnidae, Didemnum duplicatum Monniot, 1983, D. psammathodes Sluiter, 1895, and Polysyncraton amethysteum Van Name, 1902, and an unidentified species of Polycitoridae, Eudistoma sp. 1, were recruited. Presenting continuous recruitment of all species, the density of living and dead recruits and colonies was similar on both faces of the rocks. The highest rainfall during winter, affected significantly the recruits density of D. duplicatum and D. psammathodes. Different permanence periods were observed for colonies of each species. The longest permanence periods were assigned to the colonies of P. amethysteum and D. psammathodes, extending up to four and five months, respectively.A partir de substrato natural raspado, o recrutamento e a colonização de ascídias coloniais foi observado ao longo de um ano, em unidades amostrais delimitadas sobre as faces mar e continente de rochas situadas na franja do infralitoral de uma praia exposta no nordeste do Brasil. Foram recrutadas as espécies de Didemnidae, Didemnum duplicatum Monniot, 1983, D. psammathodes Sluiter, 1895 e Polysyncraton amethysteum Van Name, 1902 e uma espécie não-identificada de Polycitoridae, Eudistoma sp. 1. Apresentando recrutamento contínuo de todas as espécies, a densidade de colônias e de recrutas vivos e mortos foi similar nas duas faces das rochas. Durante o inverno, a densidade de recrutas de D. duplicatum e de D. psammathodes foi significativamente afetada pela intensa pluviosidade. As colônias de cada espécie apresentaram diferentes períodos de permanência sobre as rochas. Com duração de quatro e cinco meses, os maiores períodos de permanência foram assinalados para as colônias de P

  11. Vessel generator noise as a settlement cue for marine biofouling species.

    Science.gov (United States)

    McDonald, J I; Wilkens, S L; Stanley, J A; Jeffs, A G

    2014-01-01

    Underwater noise is increasing globally, largely due to increased vessel numbers and international ocean trade. Vessels are also a major vector for translocation of non-indigenous marine species which can have serious implications for biosecurity. The possibility that underwater noise from fishing vessels may promote settlement of biofouling on hulls was investigated for the ascidian Ciona intestinalis. Spatial differences in biofouling appear to be correlated with spatial differences in the intensity and frequency of the noise emitted by the vessel's generator. This correlation was confirmed in laboratory experiments where C. intestinalis larvae showed significantly faster settlement and metamorphosis when exposed to the underwater noise produced by the vessel generator. Larval survival rates were also significantly higher in treatments exposed to vessel generator noise. Enhanced settlement attributable to vessel generator noise may indicate that vessels not only provide a suitable fouling substratum, but vessels running generators may be attracting larvae and enhancing their survival and growth.

  12. Desiccation as a mitigation tool to manage biofouling risks: trials on temperate taxa to elucidate factors influencing mortality rates.

    Science.gov (United States)

    Hopkins, Grant A; Prince, Madeleine; Cahill, Patrick L; Fletcher, Lauren M; Atalah, Javier

    2016-01-01

    The desiccation tolerance of biofouling taxa (adults and early life-stages) was determined under both controlled and 'realistic' field conditions. Adults of the ascidian Ciona spp. died within 24 h. Mortality in the adult blue mussel Mytilus galloprovincialis occurred within 11 d under controlled conditions, compared with 7 d when held outside. The Pacific oyster Crassostrea gigas was the most desiccation-tolerant taxon tested (up to 34 d under controlled conditions). Biofouling orientated to direct sunlight showed faster mortality rates for all the taxa tested. Mortality in Mytilus juveniles took up to 24 h, compared with 8 h for Ciona, with greater survival at the higher temperature (18.5°C) and humidity (~95% RH) treatment combination. This study demonstrated that desiccation can be an effective mitigation method for a broad range of fouling taxa, especially their early life-stages. Further work is necessary to assess risks from other high-risk species such as algae and cyst forming species.

  13. Toll-like receptors of deuterostome invertebrates

    Directory of Open Access Journals (Sweden)

    Honoo eSatake

    2012-02-01

    Full Text Available Defensive systems against pathogens are responsible not only for survival or lifetime of an individual but also for the evolution of a species. Innate immunity is expected to be more important for invertebrates than mammals, given that adaptive immunity has not been acquired in the former. Toll-like receptors (TLRs have been shown to play a crucial role in host defense of pathogenic microbes in innate immunity of mammals. Recent genome-wide analyses have suggested that TLR or their related genes are conserved in invertebrates. In particular, numerous TLR-related gene candidates were detected in deuterostome invertebrates including a sea urchin (222 TLR-related gene candidates and amphioxus (72 TLR-related gene candidates. Molecular phylogenetic analysis verified that most of sea urchin or amphioxus TLR candidates are paralogous, suggesting that these organisms expanded TLR-related genes in a species-specific manner. In contrast, another deuterostome invertebrate, an ascidian, Ciona intestinalis, was found to possess only two TLR genes. Moreover, Ciona TLRs, Ci-TLR1 and -2, were shown to possess hybrid functionality of mammalian TLRs. Such functionality of Ci-TLRs could not be predicted by sequence comparison with vertebrate TLRs, indicating the confounding evolutionary lineages of deuterostome invertebrate TLRs or their candidates. In this review article, we present recent advances in studies of TLRs or their candidates of deuterostome invertebrates, and provide insight into an evolutionary process of TLRs.

  14. Seasonal, annual, and spatial variation in the development of hard bottom communities

    Science.gov (United States)

    Harms, J.; Anger, K.

    1983-06-01

    The development of hard bottom communities has been studied on test panels in Helgoland Harbour (German Bight) since 1977. Settlement and growth of epibenthic species was examined monthly. Natural variation in different seasons, years, and at three stations (the latter, only in 1981 and 1982) was investigated. At Station A (Binnenhafen), barnacles (Balanus crenatus) and polychaetes (Polydora ciliata) were always among the first settlers in spring. They were followed by other barnacles (Elminius modestus, Balanus improvisus) and by colonial ascidians (Botryllus schlosseri). The latter species often dominated from August to October, and tended to overgrow the barnacle populations. E. modestus showed strong annual variation, probably due to extremely low winter temperatures: after the cold winter of 1978/79, its populations were less dense than in previous years. In 1981 they recovered, and settlement increased again, but the cold winter 1981/82 damaged the population again. At Station B (Nordosthafen), mussels (Mytilus edulis) soon covered barnacles and empty space. By October they had monopolized the fouling community. At Station C (Südhafen), barnacle settlement in spring was followed by an overgrowth of hydrozoans ( Laomedea spec.). In summer, ascidians ( Ciona intestinalis and Ascidiella aspersa) settled and began to dominate. Barnacles were weaker in the competition for space as opposed to later colonizers at all three stations.

  15. Two New Cholic Acid Derivatives from the Marine Ascidian-Associated Bacterium Hasllibacter halocynthiae

    Directory of Open Access Journals (Sweden)

    Sung Hun Kim

    2012-10-01

    Full Text Available The investigation of secondary metabolites in liquid cultures of a recently discovered marine bacterium, Hasllibacter halocynthiae strain KME 002T, led to the isolation of two new cholic acid derivatives. The structures of these compounds were determined to be 3,3,12-trihydroxy-7-ketocholanic acid (1 and 3,3,12-trihydroxy-7-deoxycholanic acid (2 through HRFABMS and NMR data analyses.

  16. Fungicidal compounds from a marine Ascidian-associated fungus Trichoderma harzianum

    Digital Repository Service at National Institute of Oceanography (India)

    PrabhaDevi; Ciavatta, M.L.; Wahidullah, S.; Vuppala, S.; DeSouza, L.

    . Of the five isolated secondary metabolites, compounds 2 and 5 are being reported here for the first time from T. harzianum. Compounds 1 and 4 inhibited the growth of Sclerotium rolfsii causing sclerotium wilt or rot disease in tropical plants. Compound 2 and 5...

  17. Intense predation on ascidians by a trunk fish, Ostracion immaculatus (Temminck et Schlege) (Pisces:Ostracidae)

    Digital Repository Service at National Institute of Oceanography (India)

    Raveendran, T.V; Harada, E.

    stream_size 9 stream_content_type text/plain stream_name Publ_Seto_Mar_Biol_Lab_37_193.pdf.txt stream_source_info Publ_Seto_Mar_Biol_Lab_37_193.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset=ISO-8859-1 ...

  18. Dermatan sulfate in tunicate phylogeny: Order-specific sulfation pattern and the effect of [→4IdoA(2-Sulfateβ-1→3GalNAc(4-Sulfateβ-1→] motifs in dermatan sulfate on heparin cofactor II activity

    Directory of Open Access Journals (Sweden)

    Sugahara Kazuyuki

    2011-05-01

    Full Text Available Abstract Background Previously, we have reported the presence of highly sulfated dermatans in solitary ascidians from the orders Phlebobranchia (Phallusia nigra and Stolidobranchia (Halocynthia pyriformis and Styela plicata. Despite the identical disaccharide backbone, consisting of [→4IdoA(2Sβ-1→3GalNAcβ-1→], those polymers differ in the position of sulfation on the N-Acetyl galactosamine, which can occur at carbon 4 or 6. We have shown that position rather than degree of sulfation is important for heparin cofactor II activity. As a consequence, 2,4- and 2,6-sulfated dermatans have high and low heparin cofactor II activities, respectively. In the present study we extended the disaccharide analysis of ascidian dermatan sulfates to additional species of the orders Stolidobranchia (Herdmania pallida, Halocynthia roretzi and Phlebobranchia (Ciona intestinalis, aiming to investigate how sulfation evolved within Tunicata. In addition, we analysed how heparin cofactor II activity responds to dermatan sulfates containing different proportions of 2,6- or 2,4-disulfated units. Results Disaccharide analyses indicated a high content of disulfated disaccharide units in the dermatan sulfates from both orders. However, the degree of sulfation decreased from Stolidobranchia to Phlebobranchia. While 76% of the disaccharide units in dermatan sulfates from stolidobranch ascidians are disulfated, 53% of disulfated disaccharides are found in dermatan sulfates from phlebobranch ascidians. Besides this notable difference in the sulfation degree, dermatan sulfates from phlebobranch ascidians contain mainly 2,6-sulfated disaccharides whereas dermatan sulfate from the stolidobranch ascidians contain mostly 2,4-sulfated disaccharides, suggesting that the biosynthesis of dermatan sulfates might be differently regulated during tunicates evolution. Changes in the position of sulfation on N-acetylgalactosamine in the disaccharide [→4IdoA(2-Sulfateβ-1→3GalNAcβ-1

  19. A glycine receptor is involved in the organization of swimming movements in an invertebrate chordate

    Directory of Open Access Journals (Sweden)

    Okamura Yasushi

    2010-01-01

    Full Text Available Abstract Background Rhythmic motor patterns for locomotion in vertebrates are generated in spinal cord neural networks known as spinal Central Pattern Generators (CPGs. A key element in pattern generation is the role of glycinergic synaptic transmission by interneurons that cross the cord midline and inhibit contralaterally-located excitatory neurons. The glycinergic inhibitory drive permits alternating and precisely timed motor output during locomotion such as walking or swimming. To understand better the evolution of this system we examined the physiology of the neural network controlling swimming in an invertebrate chordate relative of vertebrates, the ascidian larva Ciona intestinalis. Results A reduced preparation of the larva consisting of nerve cord and motor ganglion generates alternating swimming movements. Pharmacological and genetic manipulation of glycine receptors shows that they are implicated in the control of these locomotory movements. Morphological molecular techniques and heterologous expression experiments revealed that glycine receptors are inhibitory and are present on both motoneurones and locomotory muscle while putative glycinergic interneurons were identified in the nerve cord by labeling with an anti-glycine antibody. Conclusions In Ciona intestinalis, glycine receptors, glycinergic transmission and putative glycinergic interneurons, have a key role in coordinating swimming movements through a simple CPG that is present in the motor ganglion and nerve cord. Thus, the strong association between glycine receptors and vertebrate locomotory networks may now be extended to include the phylum chordata. The results suggest that the basic network for 'spinal-like' locomotion is likely to have existed in the common ancestor of extant chordates some 650 M years ago.

  20. An expanded Notch-Delta model exhibiting long-range patterning and incorporating MicroRNA regulation.

    Directory of Open Access Journals (Sweden)

    Jerry S Chen

    2014-06-01

    Full Text Available Notch-Delta signaling is a fundamental cell-cell communication mechanism that governs the differentiation of many cell types. Most existing mathematical models of Notch-Delta signaling are based on a feedback loop between Notch and Delta leading to lateral inhibition of neighboring cells. These models result in a checkerboard spatial pattern whereby adjacent cells express opposing levels of Notch and Delta, leading to alternate cell fates. However, a growing body of biological evidence suggests that Notch-Delta signaling produces other patterns that are not checkerboard, and therefore a new model is needed. Here, we present an expanded Notch-Delta model that builds upon previous models, adding a local Notch activity gradient, which affects long-range patterning, and the activity of a regulatory microRNA. This model is motivated by our experiments in the ascidian Ciona intestinalis showing that the peripheral sensory neurons, whose specification is in part regulated by the coordinate activity of Notch-Delta signaling and the microRNA miR-124, exhibit a sparse spatial pattern whereby consecutive neurons may be spaced over a dozen cells apart. We perform rigorous stability and bifurcation analyses, and demonstrate that our model is able to accurately explain and reproduce the neuronal pattern in Ciona. Using Monte Carlo simulations of our model along with miR-124 transgene over-expression assays, we demonstrate that the activity of miR-124 can be incorporated into the Notch decay rate parameter of our model. Finally, we motivate the general applicability of our model to Notch-Delta signaling in other animals by providing evidence that microRNAs regulate Notch-Delta signaling in analogous cell types in other organisms, and by discussing evidence in other organisms of sparse spatial patterns in tissues where Notch-Delta signaling is active.

  1. Voltage sensitive phosphatases: emerging kinship to protein tyrosine phosphatases from structure-function research

    Directory of Open Access Journals (Sweden)

    Kirstin eHobiger

    2015-02-01

    Full Text Available The transmembrane protein Ci-VSP from the ascidian Ciona intestinalis was described as first member of a fascinating family of enzymes, the voltage sensitive phosphatases (VSPs. Ci-VSP and its voltage-activated homologs from other species are stimulated by positive membrane potentials and dephosphorylate the head groups of negatively charged phosphoinositide phosphates (PIPs. In doing so, VSPs act as control centers at the cytosolic membrane surface, because they intervene in signaling cascades that are mediated by PIP lipids. The characteristic motif CX5RT/S in the active site classifies VSPs as members of the huge family of cysteine-based protein tyrosine phosphatases (PTPs. Although PTPs have already been well characterized regarding both, structure and function, their relationship to VSPs has drawn only limited attention so far. Therefore, the intention of this review is to give a short overview about the extensive knowledge about PTPs in relation to the facts known about VSPs. Here, we concentrate on the structural features of the catalytic domain which are similar between both classes of phosphatases and their consequences for the enzymatic function. By discussing results obtained from crystal structures, molecular dynamics simulations, and mutagenesis studies, a possible mechanism for the catalytic cycle of VSPs is presented based on that one proposed for PTPs. In this way, we want to link the knowledge about the catalytic activity of VSPs and PTPs.

  2. Biomixing generated by benthic filterfeeders: A diffusion model for near-bottom phytoplankton depletion

    DEFF Research Database (Denmark)

    Scheel Larsen, Poul; Riisgård, H.U.

    1997-01-01

    -feeders, the polychaete Nereis diversicolor and the ascidian Ciona intestinalis, respectively. The model is based on sinks located at inhalant openings and Fick's law with an effective diffusivity that decreases with distance above the bottom due to the biomixing generated by exhalant and inhalant feeding currents. For N....... diversicolor, having inhalant and exhalant openings flush with the sediment surface and a moderate exhalant jet velocity of about 0.01 m s-1, concentration boundary layer growth is retarded and limited by the low values of diffusivity prevailing at heights greater than about 0.05 m above the bottom. For C....... intestinalis, having inhalant and exhalant openings situated about 0.05-0.1 m above the bottom and a higher and inclined exhalant jet velocity of about 0.1-0.2 m s-1, the concentration distributions show a nearly uniform depletion over a layer reaching a thickness of 0.2-0.3 m above the bottom due to high...

  3. β‐catenin‐driven binary cell fate decisions in animal development

    Science.gov (United States)

    2016-01-01

    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. WIREs Dev Biol 2016, 5:377–388. doi: 10.1002/wdev.228 For further resources related to this article, please visit the WIREs website. PMID:26952169

  4. Ciona intestinalis as a Marine Model System to Study Some Key Developmental Genes Targeted by the Diatom-Derived Aldehyde Decadienal

    OpenAIRE

    Anna Lettieri; Rosaria Esposito; Adrianna Ianora; Antonietta Spagnuolo

    2015-01-01

    The anti-proliferative effects of diatoms, described for the first time in copepods, have also been demonstrated in benthic invertebrates such as polychaetes, sea urchins and tunicates. In these organisms PUAs (polyunsaturated aldehydes) induce the disruption of gametogenesis, gamete functionality, fertilization, embryonic mitosis, and larval fitness and competence. These inhibitory effects are due to the PUAs, produced by diatoms in response to physical damage as occurs during copepod grazin...

  5. Two mannose-binding lectin homologues and an MBL-associated serine protease are expressed in the gut epithelia of the urochordate species Ciona intestinalis

    DEFF Research Database (Denmark)

    Skjoedt, Mikkel-ole; Palarasah, Yaseelan; Rasmussen, Karina

    2010-01-01

    interchain disulphide bridges between N-terminal cysteine residues and cysteines located between the neck region and the CRD. RT-PCR showed a tissue specific expression of CioMBL in the gut and by immunohistochemistry analysis we also demonstrated that CioMBL co-localize with an MBL-associated serine...... protease in the epithelia cells lining the stomach and intestine. In conclusion we present two urochordate MBLs and identify an associated serine protease, which support the concept of an evolutionary ancient origin of the lectin complement pathway....

  6. The apoptotic initiator caspase-8: its functional ubiquity and genetic diversity during animal evolution.

    Science.gov (United States)

    Sakamaki, Kazuhiro; Shimizu, Kouhei; Iwata, Hiroaki; Imai, Kenichiro; Satou, Yutaka; Funayama, Noriko; Nozaki, Masami; Yajima, Mamiko; Nishimura, Osamu; Higuchi, Mayura; Chiba, Kumiko; Yoshimoto, Michi; Kimura, Haruna; Gracey, Andrew Y; Shimizu, Takashi; Tomii, Kentaro; Gotoh, Osamu; Akasaka, Koji; Sawasaki, Tatsuya; Miller, David J

    2014-12-01

    The caspases, a family of cysteine proteases, play multiple roles in apoptosis, inflammation, and cellular differentiation. Caspase-8 (Casp8), which was first identified in humans, functions as an initiator caspase in the apoptotic signaling mediated by cell-surface death receptors. To understand the evolution of function in the Casp8 protein family, casp8 orthologs were identified from a comprehensive range of vertebrates and invertebrates, including sponges and cnidarians, and characterized at both the gene and protein levels. Some introns have been conserved from cnidarians to mammals, but both losses and gains have also occurred; a new intron arose during teleost evolution, whereas in the ascidian Ciona intestinalis, the casp8 gene is intronless and is organized in an operon with a neighboring gene. Casp8 activities are near ubiquitous throughout the animal kingdom. Exogenous expression of a representative range of nonmammalian Casp8 proteins in cultured mammalian cells induced cell death, implying that these proteins possess proapoptotic activity. The cnidarian Casp8 proteins differ considerably from their bilaterian counterparts in terms of amino acid residues in the catalytic pocket, but display the same substrate specificity as human CASP8, highlighting the complexity of spatial structural interactions involved in enzymatic activity. Finally, it was confirmed that the interaction with an adaptor molecule, Fas-associated death domain protein, is also evolutionarily ancient. Thus, despite structural diversity and cooption to a variety of new functions, the ancient origins and near ubiquitous distribution of this activity across the animal kingdom emphasize the importance and utility of Casp8 as a central component of the metazoan molecular toolkit.

  7. The evolving proteome of a complex extracellular matrix, the Oikopleura house.

    Directory of Open Access Journals (Sweden)

    Julia Hosp

    Full Text Available Extracellular matrices regulate biological processes at the level of cells, tissues, and in some cases, entire multicellular organisms. The subphylum Urochordata exemplifies the latter case, where animals are partially or completely enclosed in "houses" or "tunics". Despite this common strategy, we show that the house proteome of the appendicularian, Oikopleura, has very little in common with the proteome of the sister class, ascidian, Ciona. Of 80 identified house proteins (oikosins, ∼half lack domain modules or similarity to known proteins, suggesting de novo appearance in appendicularians. Gene duplication has been important in generating almost 1/3 of the current oikosin complement, with serial duplications up to 8 paralogs in one family. Expression pattern analyses revealed that individual oikosins are produced from specific fields of cells within the secretory epithelium, but in some cases, migrate up to at least 20 cell diameters in extracellular space to combine in defined house structures. Interestingly, peroxidasin and secretory phospholipase A(2 domains, implicated in innate immune defence are secreted from the anlage associated with the food-concentrating filter, suggesting that this extra-organismal structure may play, in part, such a role in Oikopleura. We also show that sulfation of proteoglycans is required for the hydration and inflation of pre-house rudiments into functional houses. Though correct proportioning in the production of oikosins would seem important in repetitive assembly of the complex house structure, the genomic organization of oikosin loci appears incompatible with common enhancers or locus control regions exerting such a coordinate regulatory role. Thus, though all tunicates employ extracellular matrices based on a cellulose scaffold as a defining feature of the subphylum, they have evolved radically different protein compositions associated with this common underlying structural theme.

  8. Evolutionary embryology resurrected in Japan with a new molecular basis: Nori Satoh and the history of ascidian studies originating in Kyoto during the 20th century.

    Science.gov (United States)

    Kuratani, Shigeru; Wada, Hiroshi; Kusakabe, Rie; Agata, Kiyokazu

    2006-01-01

    This article briefly summarizes the scientific contributions of Nori Satoh, the winner of the 2005 edition of the Kowalevsky Medal, to Developmental Biology and especially to Evo-Devo with his 30 years of research on tunicates - a primitive chordate species. His research began with his pure developmental interest in the clock mechanism of cell differentiation and later expanded into various aspects of evolutionary and developmental phenomena. He is not only known as a founder of molecular biology-based tunicate studies, but also for his world-wide service to education and his prestigious publications in international scientific journals.

  9. Construction and characterization of large-insert genomic libraries (BAC and fosmid) from the Ascidian Botryllus schlosseri and initial physical mapping of a histocompatibility locus.

    Science.gov (United States)

    de Tomaso, Anthony W; Weissman, Irving L

    2003-01-01

    The colonial protochordate Botryllus schlosseri is genetically manipulable and represents a potential model organism for a variety of biological disciplines, including immunology, stem cell biology and development. This article presents the construction and characterization of both BAC and fosmid genomic libraries of the 725-Mbp B. schlosseri genome. The BAC library currently consists of 2x genome coverage with an average insert size of 80 kb. The fosmid library is at 11x genome coverage with an average insert of 40 kb. B. schlosseri is a small organism containing a large number of compounds that hinder DNA purification. Thus a number of protocols had to be modified in order to make purified, high molecular weight inserts for cloning, including both gel purification and insert concentration techniques. Both libraries were characterized by using them in initial physical mapping of a single histocompatibility locus, and were found to be representative and functional. These libraries are important tools for physical mapping and positional cloning in the B. schlosseri genome, and the techniques adapted to make them are suitable for use on other organisms in which high molecular weight DNA is difficult to purify.

  10. 海鞘脂肪含量及其脂肪酸组成%Determination of Content of Fat and Composition of Fatty Acids in Ascidian

    Institute of Scientific and Technical Information of China (English)

    许波; 张秀妍; 金海珠; 王长海

    2003-01-01

    对烟台渤海湾的柄海鞘和玻璃海鞘的脂肪含量及其脂肪酸组成进行了分析,并对其提取工艺进行了研究.结果表明,海鞘中的脂肪以乙醚为溶剂,提取3h较为理想.脂肪总含量,玻璃海鞘为干重的6.16%;柄海鞘的含量为干重的5.02%,其中内囊的含量占10.68%、海鞘皮中的含量为1.14%.气相色谱及色-质谱分析的结果表明,柄海鞘内囊中的不饱和脂肪酸(UFA)占脂肪酸总量的56.44%,其中多不饱和脂肪酸(PUFA)为37.57%,EPA+DHA占18.98%;玻璃海鞘中UFA占脂肪酸总量的36.68%,其中PUFA为23.34%,EPA+DHA占9.8%.

  11. Reproductive protein evolution in two cryptic species of marine chordate

    Directory of Open Access Journals (Sweden)

    Harrison Richard G

    2011-01-01

    Full Text Available Abstract Background Reproductive character displacement (RCD is a common and taxonomically widespread pattern. In marine broadcast spawning organisms, behavioral and mechanical isolation are absent and prezygotic barriers between species often operate only during the fertilization process. Such barriers are usually a consequence of differences in the way in which sperm and egg proteins interact, so RCD can be manifest as faster evolution of these proteins between species in sympatry than allopatry. Rapid evolution of these proteins often appears to be a consequence of positive (directional selection. Here, we identify a set of candidate gamete recognition proteins (GRPs in the ascidian Ciona intestinalis and showed that these GRPs evolve more rapidly than control proteins (those not involved in gamete recognition. Choosing a subset of these gamete recognition proteins that show evidence of positive selection (CIPRO37.40.1, CIPRO60.5.1, CIPRO100.7.1, we then directly test the RCD hypothesis by comparing divergence (omega and polymorphism (McDonald-Kreitman, Tajima's D, Fu and Li's D and F, Fay and Wu's H statistics in sympatric and allopatric populations of two distinct forms of C. intestinalis (Types A and B between which there are strong post-zygotic barriers. Results Candidate gamete recognition proteins from two lineages of C. intestinalis (Type A and B are evolving more rapidly than control proteins, consistent with patterns seen in insects and mammals. However, ω (dN/dS is not significantly different between the sympatric and allopatric populations, and none of the polymorphism statistics show significant differences between sympatric and allopatric populations. Conclusions Enhanced prezygotic isolation in sympatry has become a well-known feature of gamete recognition proteins in marine broadcast spawners. But in most cases the evolutionary process or processes responsible for this pattern have not been identified. Although gamete

  12. Dicty_cDB: VHA612 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available inalis cDNA, clone:cits45g14, 5' end, single read. 80 4e-13 2 BW503370 |BW503370.1 Ciona intestinalis early ...9, 5' end, single read. 80 5e-13 2 BW505135 |BW505135.1 Ciona intestinalis early juvenile cDNA, clone: cijm0

  13. Adaptive behaviour of fishers to external perturbations: simulation of the Tasmanian rock lobster fishery

    NARCIS (Netherlands)

    Hamon, K.G.; Frusher, S.D.; Little, L.R.; Thebaud, O.; Punt, A.E.

    2014-01-01

    The rock lobster, Jasus edwardsii, lies on a global "hotspot" for climate change in the southeastern Australian state of Tasmania. The short-term effects of climate change are predicted to lead to an increasing exploitable biomass in the south and declining biomass in the north of the state. The fut

  14. NCBI nr-aa BLAST: CBRC-OANA-01-2119 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available factor) (ADF) (Ascidian gelsolin) dbj|BAA28674.1| ascidian cytoplasmic gelsolin [Halocynthia roretzi] O61270 0.89 32% ... ...CBRC-OANA-01-2119 sp|O61270|GELS_HALRO Gelsolin, cytoplasmic (Actin-depolymerizing

  15. Larvae of fouling organisms and macrofouling at New Mangalore Port, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Khandeparker, D.C.; Anil, A.C.; Venkat, K.

    throughout the year, their representation in the macrofouling community was not prominent and yielded a poor correlation with recruitment. Bryozoan and ascidian larvae were sparsely encountered but indicated as significant correlation with their recruitment...

  16. Mechanisms of biotic resistance across complex life cycles.

    Science.gov (United States)

    Rius, Marc; Potter, Elaine E; Aguirre, J David; Stachowicz, John J

    2014-01-01

    Biotic resistance is the ability of communities to inhibit the establishment, spread or impact of novel species. However, the interactions that underlie biotic resistance depend heavily on the contexts in which species interact. Consequently, studies of biotic resistance that consider single processes, patches, species or life-history stages may provide an incomplete picture of the capacity for communities to resist invasion. Many organisms have multiphasic life cycles, where individuals can occupy distinct niches at different stages of the life history. Generally, studies of biotic resistance focus on interactions within a single life-history stage, and interactions at other life-history stages are overlooked. Here, we demonstrate that different mechanisms of biotic resistance occur across the life history and together limit the invasion success of an introduced marine invertebrate (Ciona intestinalis) in Northern California. We tested the role of interactions (competition and predation) with the resident community in limiting the abundance of Ciona through experiments conducted on fertilization, larval survival, settlement, early postsettlement survival, and the survival of juveniles and adults. Under some circumstances, Ciona became abundant in mid-successional stages and showed more rapid growth rates than a morphologically similar native species, Ascidia ceratodes. However, predators reduced Ciona abundance much more than that of Ascidia at several life stages. Furthermore, Ciona appeared to be a weaker competitor at the adult stage. Early life-history interactions with other sessile species at the fertilization, larval and recruit stages had modest to no effects on Ciona abundance. The presence of biotic resistance mechanisms acting at multiple life stages, and potentially under different conditions, suggests that different components of biotic resistance interact to enhance the resident community's resistance to invasion.

  17. Field assessment of the predation risk-food availability trade-off in crab megalopae settlement.

    Directory of Open Access Journals (Sweden)

    Sebastián Tapia-Lewin

    Full Text Available Settlement is a key process for meroplanktonic organisms as it determines distribution of adult populations. Starvation and predation are two of the main mortality causes during this period; therefore, settlement tends to be optimized in microhabitats with high food availability and low predator density. Furthermore, brachyuran megalopae actively select favorable habitats for settlement, via chemical, visual and/or tactile cues. The main objective in this study was to assess the settlement of Metacarcinus edwardsii and Cancer plebejus under different combinations of food availability levels and predator presence. We determined, in the field, which factor is of greater relative importance when choosing a suitable microhabitat for settling. Passive larval collectors were deployed, crossing different scenarios of food availability and predator presence. We also explore if megalopae actively choose predator-free substrates in response to visual and/or chemical cues. We tested the response to combined visual and chemical cues and to each individually. Data was tested using a two-way factorial design ANOVA. In both species, food did not cause significant effect on settlement success, but predator presence did, therefore there was not trade-off in this case and megalopae respond strongly to predation risk by active aversion. Larvae of M. edwardsii responded to chemical and visual cues simultaneously, but there was no response to either cue by itself. Statistically, C. plebejus did not exhibit a differential response to cues, but reacted with a strong similar tendency as M. edwardsii. We concluded that crab megalopae actively select predator-free microhabitat, independently of food availability, using chemical and visual cues combined. The findings in this study highlight the great relevance of predation on the settlement process and recruitment of marine invertebrates with complex life cycles.

  18. Dicty_cDB: VHJ883 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available omosome 2 map 3879572... 127 2e-25 1 ( BJ442734 ) Dictyostelium discoideum cDNA clone:ddv50f22, 3' ... 127 2...e-25 1 ( BJ423915 ) Dictyostelium discoideum cDNA clone:ddv50f22, 5' ... 98 2e-16 1 ( BP018838 ) Ciona intes

  19. Dicty_cDB: Contig-U03756-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available s panic... 38 2e-06 4 ( BW587469 ) Ciona savignyi cDNA, clone:csef030d09, 3'end, sin... 40 3e-06 3 ( AF435805 ) Malus micromalus...tis elegans cosmid F09C12, ... 97 7e-53 AF435805_1( AF435805 |pid:none) Malus micromalus mitogen-activated..

  20. Dicty_cDB: Contig-U12072-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available tein 1 ... 59 3e-07 S00670( S00670 ;A26637) neurogenic repetitive locus delta protein ... 59 3e-07 (Q9NYJ7) ...Q900934 |pid:none) Ciona intestinalis gamma-carboxygl... 59 3e-07 A31246( A31246 )neurogenic protein Delta p

  1. Protein: FBA5 [TP Atlas

    Lifescience Database Archive (English)

    Full Text Available FBA5 VSOP(voltage sensor-only protein1) HVCN1 VSOP, VSX1 Voltage-gated hydrogen cha...nnel 1 Hydrogen voltage-gated channel 1, Voltage sensor domain-only protein 7719 Ciona intestinalis 778897 Q1JV40 ...

  2. Isolation of C11 Cyclopentenones from Two Didemnid Species, Lissoclinum sp. and Diplosoma sp.

    Directory of Open Access Journals (Sweden)

    Katsuhiro Ueda

    2009-12-01

    Full Text Available A series of new C11 cyclopentenones 1-7 was isolated, together with four known metabolites 9/10, 12 and 13, from the extract of the didemnid ascidian Lissoclinum sp. The other didemnid ascidian Diplosoma sp. contained didemnenones 1, 2 and 5, and five known metabolites 8-12. The structures of 1-7 were elucidated by spectroscopic analyses. Cytotoxicity of the isolated compounds was evaluated against three human cancer cell lines (HCT116, A431 and A549.

  3. Highly Connected Populations and Temporal Stability in Allelic Frequencies of a Harvested Crab from the Southern Pacific Coast

    Science.gov (United States)

    Rojas-Hernandez, Noemi; Veliz, David; Riveros, Marcela P; Fuentes, Juan P.; Pardo, Luis M.

    2016-01-01

    For marine invertebrates with a benthic adult form and a planktonic larva phase, the connectivity among populations is mainly based on larval dispersal. While an extended larval phase will promote gene flow, other factors such as an intensive fishery and geographical barriers could lead to changes in genetic variability. In this study, the population genetic structure of the commercial crab Metacarcinus edwardsii was analyzed along 700 km of the Chilean coast. The analysis, based on eight microsatellite loci genotyped from megalopae and adult crabs, considered temporal and spatial patterns of genetic variation. The results showed no evidence of spatial patterns in genetic structure, suggesting high connectivity among the sampling sites. The temporal analysis showed no evidence of changes in allele frequencies and no evidence of a recent bottleneck. The lack of spatial structure and allele variation over time could be explained by the interaction of factors such as i) low reproductive variance due to the capability of females to store sperm in the seminal receptacle, which can be used for successive broods, ii) high larval dispersal and iii) high individual reproductive output. Using our data as priors, a genetic modelling approach coincided, predicting this temporal and spatial stability. The same analysis showed that a reduction in population size leads to the loss of genetic variability in populations, as well as of the genetic cohesiveness between populations, pointing out the importance management for species under exploitation, such as M. edwardsii. PMID:27814382

  4. A new species of Streblosoma Sars, 1872 (Polychaeta, Terebellidae, Thelepodinae) from Brazil, with comments on Streblosoma oligobranchiatum Nogueira & Amaral, 2001

    NARCIS (Netherlands)

    Matos Nogueira, de João Miguel; Garraffoni, André Rinaldo Senna; Montrezoro Alves, Tarsila

    2004-01-01

    A new species of Streblosoma is described and the diagnosis of S. oligobranchiatum is emended, based on material collected on intertidal rocky shores along the State of São Paulo, Brazil, associated with algae, sponges, ascidians and other sedentary polychaetes. Streblosoma porchatensis n. sp. is ch

  5. Viscosity and not biological mechanisms often controls the effects of temperature on ciliary activity and swimming velocity of small aquatic organisms

    DEFF Research Database (Denmark)

    Larsen, Poul Scheel; Riisgård, H. U.

    2009-01-01

    A number of studies have shown that temperature-dependent viscosity of the ambient water controls or strongly affects bio-mechanical activity such as beat frequency of water-pumping cilia in mussels and ascidians, swimming velocity of sperm cells, ciliates and small (micro- and meso-scale) aquatic...

  6. Particle-capture mechanisms in suspension-feeding invertebrates

    DEFF Research Database (Denmark)

    Riisgård, Hans Ulrik; Larsen, Poul Scheel

    2010-01-01

    A large number of suspension-feeding animals (e.g. bivalves, polychaetes, ascidians, bryozoans, crustaceans, sponges, echinoderms, cnidarians) have specialized in grazing on not only the 2 to 200 µm phytoplankton but frequently also the 0.5 to 2 µm free-living bacteria in the aquatic environment...

  7. Ecology: a niche for cyanobacteria containing chlorophyll d

    DEFF Research Database (Denmark)

    Kühl, Michael; Chen, Min; Ralph, Peter J

    2005-01-01

    we demonstrate photosynthetic activity in Acaryochloris-like phototrophs that live underneath minute coral-reef invertebrates (didemnid ascidians) in a shaded niche enriched in near-infrared light. This discovery clarifies how these cyanobacteria are able to thrive as free-living organisms...

  8. ONR Tokyo Scientific Bulletin. Volume 5, Number 3, July-September 1980,

    Science.gov (United States)

    1980-09-01

    Australia - Dr. R. W. George Crustacean taxonomy Western Australian Museum Francis Street Perth. Western Australia 6000 Australia - Dr. P. Mather Ascidian...Arzew, Algeria - Nobuyori Kodaira Energy problems and measures taken to promote wider Deputy Director use of LNG in Japan Development Division Petroleum

  9. The mitochondrial genome of Phallusia mammillata and Phallusia fumigata (Tunicata, Ascidiacea: high genome plasticity at intra-genus level

    Directory of Open Access Journals (Sweden)

    Pesole Graziano

    2007-08-01

    Full Text Available Abstract Background Within Chordata, the subphyla Vertebrata and Cephalochordata (lancelets are characterized by a remarkable stability of the mitochondrial (mt genome, with constancy of gene content and almost invariant gene order, whereas the limited mitochondrial data on the subphylum Tunicata suggest frequent and extensive gene rearrangements, observed also within ascidians of the same genus. Results To confirm this evolutionary trend and to better understand the evolutionary dynamics of the mitochondrial genome in Tunicata Ascidiacea, we have sequenced and characterized the complete mt genome of two congeneric ascidian species, Phallusia mammillata and Phallusia fumigata (Phlebobranchiata, Ascidiidae. The two mtDNAs are surprisingly rearranged, both with respect to one another and relative to those of other tunicates and chordates, with gene rearrangements affecting both protein-coding and tRNA genes. The new data highlight the extraordinary variability of ascidian mt genome in base composition, tRNA secondary structure, tRNA gene content, and non-coding regions (number, size, sequence and location. Indeed, both Phallusia genomes lack the trnD gene, show loss/acquisition of DHU-arm in two tRNAs, and have a G+C content two-fold higher than other ascidians. Moreover, the mt genome of P. fumigata presents two identical copies of trnI, an extra tRNA gene with uncertain amino acid specificity, and four almost identical sequence regions. In addition, a truncated cytochrome b, lacking a C-terminal tail that commonly protrudes into the mt matrix, has been identified as a new mt feature probably shared by all tunicates. Conclusion The frequent occurrence of major gene order rearrangements in ascidians both at high taxonomic level and within the same genus makes this taxon an excellent model to study the mechanisms of gene rearrangement, and renders the mt genome an invaluable phylogenetic marker to investigate molecular biodiversity and speciation

  10. Unigene BLAST: CBRC-CINT-01-0104 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-CINT-01-0104 gnl|UG|Cin#S6625795 BW185180 Nori Satoh unpublished cDNA library,... heart Ciona intestinalis cDNA clone rciht031o24 3', mRNA sequence /clone=rciht031o24 /clone_end=3' /gb=BW185180 /gi=24575512 /ug=Cin.18758 /len=771 0.32 29% ...

  11. Unigene BLAST: CBRC-CINT-01-0093 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-CINT-01-0093 gnl|UG|Cin#S6625795 BW185180 Nori Satoh unpublished cDNA library,... heart Ciona intestinalis cDNA clone rciht031o24 3', mRNA sequence /clone=rciht031o24 /clone_end=3' /gb=BW185180 /gi=24575512 /ug=Cin.18758 /len=771 0.45 37% ...

  12. Dicty_cDB: Contig-U15926-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available Y875327 ) AresSEQ2501 Amorphotheca resinae pBluescript (Eco... 44 2e-08 5 ( GE416681 ) 294498490 Nasonia vit...omplete s... 44 5e-06 2 ( DY878641 ) AresSEQ6757 Amorphotheca resinae pBluescript (Eco... 44 5e-06 4 ( DR689...6 3 ( BW436239 ) Ciona intestinalis cDNA, clone:cijv034b09, 5'end,... 40 9e-06 3 ( DY876305 ) AresSEQ3731 Amorphotheca resina

  13. Dicty_cDB: Contig-U09330-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ylem planings - daytime a... 60 1e-04 1 ( EX331539 ) GQ02903.B7_A06 GQ029 - Xylem scrapings - AT NITE ... 60... 1e-04 1 ( EX323057 ) GQ02819.SP6_M07 GQ028 - Cambium / phloem scrappin... 60 1e-04 1 ( EX322713 ) GQ02819.B...7_M07 GQ028 - Cambium / phloem scrapping... 60 1e-04 1 ( AV999726 ) Ciona intesti

  14. Dicty_cDB: Contig-U11222-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 77510 ) Ciona intestinalis cDNA, clone:cign079c11, 5' end... 44 3e-06 2 ( FF601093 ) Le_emcl1_06F12_M13Reverse Little Skate (Leucoraj...us laevis ... 58 7e-04 1 ( FF599758 ) Le_emcl1_11O22_M13Reverse Little Skate (Leucoraja... 58 7e-04 1 ( EJ48

  15. Molecular signatures that are distinctive characteristics of the vertebrates and chordates and supporting a grouping of vertebrates with the tunicates.

    Science.gov (United States)

    Gupta, Radhey S

    2016-01-01

    Members of the phylum Chordata and the subphylum Vertebrata are presently distinguished solely on the basis of morphological characteristics. The relationship of the vertebrates to the two non-vertebrate chordate subphyla is also a subject of debate. Analyses of protein sequences have identified multiple conserved signature indels (CSIs) that are specific for Chordata or for Vertebrata. Five CSIs in 4 important proteins are specific for the Vertebrata, whereas two other CSIs are uniquely found in all sequenced chordate species including Ciona intestinalis and Oikapleura dioica (Tunicates) as well as Branchiostoma floridae (Cephalochordates). The shared presence of these molecular signatures by all vertebrates/chordate species, but in no other animal taxa, strongly indicates that the genetic changes represented by the identified CSIs diagnose monophyletic groups. Two other discovered CSIs are uniquely shared by different vertebrate species and by either one (Ciona intestinalis) or both tunicate (Ciona and Oikapleura) species, but they are not found in Branchiostoma or other animal species. Specific presence of these CSIs in different vertebrates and either one or both tunicate species provides strong independent evidence that the vertebrate species are more closely related to the urochordates (tunicates) than to the cephalochordates.

  16. Dicty_cDB: Contig-U08397-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available se ... 50 5e-06 U83814_3( U83814 |pid:none) Notiomys edwardsii NADH dehydrogenase.... 50 1e-05 AF224593_4( AF224593 |pid:none) Lepilemur edwardsi isolate JP163 c... 50 1e-05 AM904728_10( AM904...d:none) Neophoca cinerea complete mitocho... 50 2e-05 DQ529606_4( DQ529606 |pid:none) Lepilemur edwards...i isolate MAR1 cy... 49 2e-05 DQ529613_4( DQ529613 |pid:none) Lepilemur edwardsi isola...te MAR27 c... 49 2e-05 AF224595_4( AF224595 |pid:none) Lepilemur edwardsi isolate JP259 c... 49 2e-05 AB2910

  17. Predation Risk within Fishing Gear and Implications for South Australian Rock Lobster Fisheries.

    Directory of Open Access Journals (Sweden)

    Felipe Briceño

    Full Text Available Depredation of southern rock lobster (Jasus edwardsii within fishing gear by the Maori octopus (Pinnoctopus cordiformis has economic and ecological impacts on valuable fisheries in South Australia. In addition, depredation rates can be highly variable resulting in uncertainties for the fishery. We examined how in-pot lobster predation was influenced by factors such as lobster size and sex, season, fishing zone, and catch rate. Using mixed modelling techniques, we found that in-pot predation risk increased with lobster size and was higher for male lobsters. In addition, the effect of catch rate of lobsters on predation risk by octopus differed among fishing zones. There was both a seasonal and a spatial component to octopus predation, with an increased risk within discrete fishing grounds in South Australia at certain times of the year. Information about predation within lobster gear can assist fishery management decision-making, potentially leading to significant reduction in economic losses to the fishery.

  18. Predation Risk within Fishing Gear and Implications for South Australian Rock Lobster Fisheries

    Science.gov (United States)

    Briceño, Felipe; Linnane, Adrian Joseph; Quiroz, Juan Carlos; Gardner, Caleb; Pecl, Gretta Tatyana

    2015-01-01

    Depredation of southern rock lobster (Jasus edwardsii) within fishing gear by the Maori octopus (Pinnoctopus cordiformis) has economic and ecological impacts on valuable fisheries in South Australia. In addition, depredation rates can be highly variable resulting in uncertainties for the fishery. We examined how in-pot lobster predation was influenced by factors such as lobster size and sex, season, fishing zone, and catch rate. Using mixed modelling techniques, we found that in-pot predation risk increased with lobster size and was higher for male lobsters. In addition, the effect of catch rate of lobsters on predation risk by octopus differed among fishing zones. There was both a seasonal and a spatial component to octopus predation, with an increased risk within discrete fishing grounds in South Australia at certain times of the year. Information about predation within lobster gear can assist fishery management decision-making, potentially leading to significant reduction in economic losses to the fishery. PMID:26489035

  19. Predation Risk within Fishing Gear and Implications for South Australian Rock Lobster Fisheries.

    Science.gov (United States)

    Briceño, Felipe; Linnane, Adrian Joseph; Quiroz, Juan Carlos; Gardner, Caleb; Pecl, Gretta Tatyana

    2015-01-01

    Depredation of southern rock lobster (Jasus edwardsii) within fishing gear by the Maori octopus (Pinnoctopus cordiformis) has economic and ecological impacts on valuable fisheries in South Australia. In addition, depredation rates can be highly variable resulting in uncertainties for the fishery. We examined how in-pot lobster predation was influenced by factors such as lobster size and sex, season, fishing zone, and catch rate. Using mixed modelling techniques, we found that in-pot predation risk increased with lobster size and was higher for male lobsters. In addition, the effect of catch rate of lobsters on predation risk by octopus differed among fishing zones. There was both a seasonal and a spatial component to octopus predation, with an increased risk within discrete fishing grounds in South Australia at certain times of the year. Information about predation within lobster gear can assist fishery management decision-making, potentially leading to significant reduction in economic losses to the fishery.

  20. Long-term coexistence of non-indigenous species in aquaculture facilities.

    Science.gov (United States)

    Rius, Marc; Heasman, Kevin G; McQuaid, Christopher D

    2011-11-01

    Non-indigenous species (NIS) are a growing problem globally and, in the sea, aquaculture activities are critical vectors for their introduction. Aquaculture introduces NIS, intentionally or unintentionally, and can provide substratum for the establishment of other NIS. Little is known about the co-occurrence of NIS over long periods and we document the coexistence over decades of a farmed NIS (a mussel) with an accidently introduced species (an ascidian). Both are widespread and cause serious fouling problems worldwide. We found partial habitat segregation across depth and the position of rafts within the studied farm, which suggests competitive exclusion of the mussel in dark, sheltered areas and physiological exclusion of the ascidian elsewhere. Both species exhibit massive self-recruitment, with negative effects on the industry, but critically the introduction of NIS through aquaculture facilities also has strong detrimental effects on the natural environment.

  1. Effects of simulated eutrophication and overfishing on algae and invertebrate settlement in a coral reef of Koh Phangan, Gulf of Thailand.

    Science.gov (United States)

    Stuhldreier, Ines; Bastian, Pepe; Schönig, Eike; Wild, Christian

    2015-03-15

    Coral reefs in the Gulf of Thailand are highly under-investigated regarding responses to anthropogenic stressors. Thus, this study simulated overfishing and eutrophication using herbivore exclosure cages and slow-release fertilizer to study the in-situ effects on benthic algae and invertebrate settlement in a coral reef of Koh Phangan, Thailand. Settlement of organisms and the development of organic matter on light-exposed and shaded tiles were quantified weekly/biweekly over a study period of 12 weeks. Simulated eutrophication did not significantly influence response parameters, while simulated overfishing positively affected dry mass, turf algae height and fleshy macroalgae occurrence on light-exposed tiles. On shaded tiles, settlement of crustose coralline algae decreased, while abundances of ascidians increased compared to controls. An interactive effect of both stressors was not observed. These results hint to herbivory as actual key controlling factor on the benthic community, and fleshy macroalgae together with ascidians as potential bioindicators for local overfishing.

  2. Engineering of Nanoscale Antifouling and Hydrophobic Surfaces on Naval Structural Steel HY-80 by Anodizing

    Science.gov (United States)

    2015-06-01

    bryozoans, barnacles, polychaete tubeworms, mollusks, and ascidians on artificial surfaces by adhesion, growth, and reproduction . Biofouling can...chemicals in the environment: Lessons from TBT,” Mar. Pollut. Bull ., vol. 22, no. 1,pp. 8–10, 1991. [6] R. Vasudevan et al., “Microscale patterned...M. Minor, “Focused ion beam microscopy and micromachining,” MRS Bull ., vol. 32, no. 5, pp. 389–399, 2007. [43] M. N. Mowry, “In situ Raman

  3. Significance of investigating allelopathic interactions of marine organisms in the discovery and development of cytotoxic compounds

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, A.; Thakur, N.L.

    to drug discovery for sustainable utilization of marine natural resources with special reference to the marine sponges. 2. Strategies to compete for space Marine invertebrates acquire living space by using various offensive and defensive strategies... common in marine hard substratum communities [32]. Amongst above four defensive strategies discussed, allelopathy or chemical defence is the most important in case of soft–bodied sessile invertebrates such as sponges, octocorals and ascidians which...

  4. Acidification effects on biofouling communities: winners and losers.

    Science.gov (United States)

    Peck, Lloyd S; Clark, Melody S; Power, Deborah; Reis, João; Batista, Frederico M; Harper, Elizabeth M

    2015-05-01

    How ocean acidification affects marine life is a major concern for science and society. However, its impacts on encrusting biofouling communities, that are both the initial colonizers of hard substrata and of great economic importance, are almost unknown. We showed that community composition changed significantly, from 92% spirorbids, 3% ascidians and 4% sponges initially to 47% spirorbids, 23% ascidians and 29% sponges after 100 days in acidified conditions (pH 7.7). In low pH, numbers of the spirorbid Neodexiospira pseudocorrugata were reduced ×5 compared to controls. The two ascidians present behaved differently with Aplidium sp. decreasing ×10 in pH 7.7, whereas Molgula sp. numbers were ×4 higher in low pH than controls. Calcareous sponge (Leucosolenia sp.) numbers increased ×2.5 in pH 7.7 over controls. The diatom and filamentous algal community was also more poorly developed in the low pH treatments compared to controls. Colonization of new surfaces likewise showed large decreases in spirorbid numbers, but numbers of sponges and Molgula sp. increased. Spirorbid losses appeared due to both recruitment failure and loss of existing tubes. Spirorbid tubes are comprised of a loose prismatic fabric of calcite crystals. Loss of tube materials appeared due to changes in the binding matrix and not crystal dissolution, as SEM analyses showed crystal surfaces were not pitted or dissolved in low pH conditions. Biofouling communities face dramatic future changes with reductions in groups with hard exposed exoskeletons and domination by soft-bodied ascidians and sponges.

  5. Phallusiasterol C, A New Disulfated Steroid from the Mediterranean Tunicate Phallusia fumigata

    Directory of Open Access Journals (Sweden)

    Concetta Imperatore

    2016-06-01

    Full Text Available A new sulfated sterol, phallusiasterol C (1, has been isolated from the Mediterranean ascidian Phallusia fumigata and its structure has been determined on the basis of extensive spectroscopic (mainly 2D NMR analysis. The possible role in regulating the pregnane X receptor (PXR activity of phallusiasterol C has been investigated; although the new sterol resulted inactive, this study adds more items to the knowledge of the structure-PXR regulating activity relationships in the case of sulfated steroids.

  6. Self/non-self recognition mechanisms in sexual reproduction: new insight into the self-incompatibility system shared by flowering plants and hermaphroditic animals.

    Science.gov (United States)

    Sawada, Hitoshi; Morita, Masaya; Iwano, Megumi

    2014-08-01

    Sexual reproduction is an essential process for generating a genetic variety in the next generation. However, most flowering plants and hermaphroditic animals potentially allow self-fertilization. Approximately 60% of angiosperms possess a self-incompatibility (SI) system to avoid inbreeding. The SI system functions at a process of interaction between pollen (or pollen tube) and the pistil. These SI-responsible factors (S-determinants) in pollen and the pistil are encoded by highly polymorphic multiallelic genes in the S-locus, which are tightly linked making a single haplotype. Different taxonomic families utilize different types of S-determinant proteins. In contrast to the plant system, the mechanisms of SI in simultaneously hermaphroditic animals are largely unknown. Among them, promising candidates for SI in ascidians (primitive chordates) were recently identified. The SI system in the ascidian Cionaintestinalis was found to be very similar to those in flowering plants: The products of sperm- and egg-side multiallelic SI genes, which are tight linked and highly polymorphic, appear to be responsible for the SI system as revealed by genetic analysis. These findings led us to speculate that the SI systems in plants and animals evolved in a manner of convergent evolution. Here, we review the current understanding of the molecular mechanisms of the SI system in flowering plants, particularly Brassicacea, and in ascidians from the viewpoint of common mechanisms shared by plants and animals.

  7. Recruitment Variability of Coral Reef Sessile Communities of the Far North Great Barrier Reef.

    Directory of Open Access Journals (Sweden)

    Heidi M Luter

    Full Text Available One of the key components in assessing marine sessile organism demography is determining recruitment patterns to benthic habitats. An analysis of serially deployed recruitment tiles across depth (6 and 12 m, seasons (summer and winter and space (meters to kilometres was used to quantify recruitment assemblage structure (abundance and percent cover of corals, sponges, ascidians, algae and other sessile organisms from the northern sector of the Great Barrier Reef (GBR. Polychaetes were most abundant on recruitment titles, reaching almost 50% of total recruitment, yet covered <5% of each tile. In contrast, mean abundances of sponges, ascidians, algae, and bryozoans combined was generally less than 20% of total recruitment, with percentage cover ranging between 15-30% per tile. Coral recruitment was very low, with <1 recruit per tile identified. A hierarchal analysis of variation over a range of spatial and temporal scales showed significant spatio-temporal variation in recruitment patterns, but the highest variability occurred at the lowest spatial scale examined (1 m-among tiles. Temporal variability in recruitment of both numbers of taxa and percentage cover was also evident across both summer and winter. Recruitment across depth varied for some taxonomic groups like algae, sponges and ascidians, with greatest differences in summer. This study presents some of the first data on benthic recruitment within the northern GBR and provides a greater understanding of population ecology for coral reefs.

  8. Evolution and the origin of the visual retinoid cycle in vertebrates.

    Science.gov (United States)

    Kusakabe, Takehiro G; Takimoto, Noriko; Jin, Minghao; Tsuda, Motoyuki

    2009-10-12

    Absorption of a photon by visual pigments induces isomerization of 11-cis-retinaldehyde (RAL) chromophore to all-trans-RAL. Since the opsins lacking 11-cis-RAL lose light sensitivity, sustained vision requires continuous regeneration of 11-cis-RAL via the process called 'visual cycle'. Protostomes and vertebrates use essentially different machinery of visual pigment regeneration, and the origin and early evolution of the vertebrate visual cycle is an unsolved mystery. Here we compare visual retinoid cycles between different photoreceptors of vertebrates, including rods, cones and non-visual photoreceptors, as well as between vertebrates and invertebrates. The visual cycle systems in ascidians, the closest living relatives of vertebrates, show an intermediate state between vertebrates and non-chordate invertebrates. The ascidian larva may use retinochrome-like opsin as the major isomerase. The entire process of the visual cycle can occur inside the photoreceptor cells with distinct subcellular compartmentalization, although the visual cycle components are also present in surrounding non-photoreceptor cells. The adult ascidian probably uses RPE65 isomerase, and trans-to-cis isomerization may occur in distinct cellular compartments, which is similar to the vertebrate situation. The complete transition to the sophisticated retinoid cycle of vertebrates may have required acquisition of new genes, such as interphotoreceptor retinoid-binding protein, and functional evolution of the visual cycle genes.

  9. Territoriality and Conflict Avoidance Explain Asociality (Solitariness of the Endosymbiotic Pea Crab Tunicotheres moseri.

    Directory of Open Access Journals (Sweden)

    Louis J Ambrosio

    Full Text Available Host monopolization theory predicts symbiotic organisms inhabiting morphologically simple, relatively small and scarce hosts to live solitarily as a result of territorial behaviors. We tested this prediction with Tunicotheres moseri, an endosymbiotic crab dwelling in the atrial chamber of the morphologically simple, small, and relatively scarce ascidian Styela plicata. As predicted, natural populations of T. moseri inhabit ascidian hosts solitarily with greater frequency than expected by chance alone. Furthermore, laboratory experiments demonstrated that intruder crabs take significantly longer to colonize previously infected compared to uninfected hosts, indicating as expected, that resident crabs exhibit monopolization behaviors. While territoriality does occur, agonistic behaviors employed by T. moseri do not mirror the overt behaviors commonly reported for other territorial crustaceans. Documented double and triple cohabitations in the field coupled with laboratory observations demonstrating the almost invariable success of intruder crabs colonizing occupied hosts, suggest that territoriality is ineffective in completely explaining the solitary social habit of this species. Additional experiments showed that T. moseri juveniles and adults, when searching for ascidians use chemical cues to avoid hosts occupied by conspecifics. This conspecific avoidance behavior reported herein is a novel strategy most likely employed to preemptively resolve costly territorial conflicts. In general, this study supports predictions central to host monopolization theory, but also implies that alternative behavioral strategies (i.e., conflict avoidance may be more important than originally thought in explaining the host use pattern of symbiotic organisms.

  10. Dicty_cDB: Contig-U15836-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 23, 5'-en... 44 0.40 2 ( EE001618 ) ROE00012490 Rhizopus oryzae Company Rhizopus oryz... 38 0.48 2 ( DX80105...OE00012886 Rhizopus oryzae Company Rhizopus oryz... 38 0.52 2 ( CF611828 ) laf05h12.y1 Gastric Epithelial Pr...BW408568 ) Ciona intestinalis cDNA, clone:cima803m04, 3'end,... 44 0.64 2 ( EE008462 ) ROE00004420 Rhizopus oryzae Company...Brassica oleracea genom... 38 0.66 3 ( EE009624 ) ROE00004013 Rhizopus oryzae Company Rhizopus oryz... 38 0.

  11. Gridded genomic libraries of different chordate species: a reference library system for basic and comparative genetic studies of chordate genomes.

    Science.gov (United States)

    Burgtorf, C; Welzel, K; Hasenbank, R; Zehetner, G; Weis, S; Lehrach, H

    1998-09-01

    The use of genomic libraries maintained in arrayed format is becoming a more and more popular tool for the analysis of molecular evolution and comparative molecular development. Being able to use already existing reference libraries considerably reduces the work load, and if results are made publicly available, it will facilitate in silica experiments in the future. Here we describe the construction and preliminary characterization of six cosmid libraries of different chordate species, Ciona intestinalis (Hemichordate), Branchiostoma floridae (Cephalochordate), Lampetra fluviatilis (Cyclostoma), Xiphophorus maculatus, and Danio rerio (Osteichthyes) in Lawrist7 and Fugu rubripes in Lawrist4.

  12. Dicty_cDB: Contig-U01152-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available BP002118 ) Ciona intestinalis cDNA, clone:ciad25e20, 5' end,... 48 0.001 3 ( CU617458 ) Theobroma cacao, mR...NA sequence (KZ0AAN4YE07FM1). 44 0.001 2 ( CU617341 ) Theobroma cacao, mRNA sequence (KZ0AAN3YE07FM1). 44 0....001 2 ( CU616827 ) Theobroma cacao, mRNA sequence (KZ0AAN11YB02FM1). 44 0.001 2 (

  13. Benthic faunal assemblages from the Holocene middle shelf of the South Evoikos Gulf, central Greece, and their palaeoenvironmental implications

    Science.gov (United States)

    Asimina Louvari, Markella; Tsourou, Theodora; Drinia, Hara; Anastasakis, George

    2013-04-01

    intermediate percentages of organic matter in which at least some sand fraction is present. A strict interpretation based on the known modern distribution of A. beccarii would confine the species to upper shoreface environments (Hayward et al. 2004). The relatively high frequency values of B. marginata indicate a correlation with organic matter enrichment, with seasonal low oxygen content. This hypothesis is testified also by the increase of the opportunistic species V. bradyana. The temporal presence of V. bradyana assemblage indicates a strong influence of Asopos River run-off, with interplay of increasing food availability and low oxygen concentration Three main ostracod assemblages were distinguished from the bottom to the top of the sediment core: At the lower part of the core ostracod assemblage consists mainly of Costa edwardsii, Cytheridea neapolitana, Callistocythere spp., Pterygocythereis jonesii and Leptocythere spp. At the middle part, Costa edwardsii is the dominant species with relative abundances up to 80% of the total ostracod fauna. At the upper part Costa edwardsii is the most abundant species (20-40% of the total fauna) accompanied mainly by Loxoconcha spp., Xestoleberis spp. and Cyprideis torosa. Ostracod abundance and diversity decrease towards the upper unit of the studied core. These data, and AMS radiocarbon ages determined for foraminifera and ostracods, provide evidence of a change from oceanic influence to estuarine influence. This event is also contemporaneous with the period which is generally characterized by increased evaporation rate (initially at the tropic seas), retreat of glaciers and increased rainfalls (Fairbanks, 1989). Fairbanks, R.G., 1989. A 17,000 year glacio-eustatic sea level record: influence of glacial melting rates on the Younger Dryas event and deep ocean circulation. Nature, 342, 637-642. Hayward, B.W., Sabaa, A.T., Grenfell, H.R., 2004. Benthic foraminifera and the Late Quaternary (last 150 ka) palaeoceanographic and

  14. Back to solitude: Solving the phylogenetic position of the Diazonidae using molecular and developmental characters.

    Science.gov (United States)

    Shenkar, Noa; Koplovitz, Gil; Dray, Liran; Gissi, Carmela; Huchon, Dorothée

    2016-07-01

    The order Aplousobranchia (Chordata, Ascidiacea) contains approximately 1500 species distributed worldwide. Their phylogeny, however, remains unclear, with unresolved family relationships. While most Aplousobranchia are colonial, debates exist concerning the phylogenetic position of families such as the Diazonidae and Cionidae, which exhibit a solitary lifestyle and share morphological characteristics with both Aplousobranchia and Phlebobranchia orders. To clarify the phylogenetic position of the Diazonidae and Cionidae, we determined the complete mitochondrial sequence of the solitary diazonid Rhopalaea idoneta. The phylogenetic reconstruction based on the 13 mitochondrial protein coding genes strongly supports a positioning of Diazonidae well-nested within the Aplousobranchia rather than a positioning as a sister clade of the Aplousobranchia. In addition, we examined the regenerative ability of R. idoneta. Similar to colonial Aplousobranchia, R. idoneta was found to be able to completely regenerate its thorax. Ciona, also known to possess high regenerative abilities, is the Aplousobranchia sister clade rather than a member of the Phlebobranchia. Our results thus indicate that the colonial lifestyle was acquired in the Aplousobranchia, starting from a Ciona-like solitary ancestor and secondarily lost in Diazonidae representatives such as Rhopalaea. The solitary lifestyle of Rhopalaea is thus a derived characteristic rather than an ancestral trait.

  15. It's a wrap: encapsulation as a management tool for marine biofouling.

    Science.gov (United States)

    Atalah, Javier; Brook, Rosemary; Cahill, Patrick; Fletcher, Lauren M; Hopkins, Grant A

    2016-01-01

    Encapsulation of fouled structures is an effective tool for countering incursions by non-indigenous biofoulers. However, guidelines for the implementation of encapsulation treatments are yet to be established. This study evaluated the effects of temperature, biomass, community composition, treatment duration and the biocide acetic acid on biofoulers. In laboratory trials using the model organisms Ciona spp. and Mytilus galloprovincialis, increasing the temperature or biomass speeded up the development of a toxic environment. Total mortality for Ciona spp. occurred within 72 and 24 h at 10 and 19°C, respectively. M. galloprovincialis survived up to 18 days, with high biomass increasing mortality at 10°C only. In a field study, three-month-old and four-year-old communities were encapsulated with and without acetic acid. Mortality took up to 10 days for communities encapsulated without acetic acid, compared to 48 h with acetic acid. The insights gained from this study will be useful in developing standardised encapsulation protocols.

  16. Mechanical constraint converts planar waves into helices on tunicate and sea urchin sperm flagella.

    Science.gov (United States)

    Ishijima, Sumio

    2012-01-01

    The change in the flagellar waves of spermatozoa from a tunicate and sea urchins was examined using high-speed video microscopy to clarify the regulation of localized sliding between doublet microtubules in the axoneme. When the tunicate Ciona spermatozoa attached to a coverslip surface by their heads in seawater or they moved in seawater with increased viscosity, the planar waves of the sperm flagella were converted into left-handed helical waves. On the other hand, conversion of the planar waves into helical waves in the sea urchin Hemicentrotus spermatozoa was not seen in seawater with an increased viscosity as well as in ordinary seawater. However, the sea urchin Clypeaster spermatozoa showed the conversion, albeit infrequently, when they thrust their heads into seawater with an increased viscosity. The chirality of the helical waves of the Clypeaster spermatozoa was right-handed. When Ciona spermatozoa swam freely near a glass surface, they moved in relatively large circular paths (yawing motion). There was no difference in the proportion of spermatozoa yawing in either a clockwise or counterclockwise direction when viewed from above, which was also different from that of the sea urchin spermatozoa. These observations suggest that the planar waves generally observed on the sperm flagella are mechanically regulated, although their stability must depend on the Ca(2+) concentration in the cell. Furthermore, the chirality of the helical waves may be determined by the intracellular Ca(2+) concentration and changed by transmitting the localized active sliding between the doublet microtubules around the axoneme in an alternative direction.

  17. The truth about mouse, human, worms and yeast

    Directory of Open Access Journals (Sweden)

    Nelson David R

    2004-01-01

    Full Text Available Abstract Genome comparisons are behind the powerful new annotation methods being developed to find all human genes, as well as genes from other genomes. Genomes are now frequently being studied in pairs to provide cross-comparison datasets. This 'Noah's Ark' approach often reveals unsuspected genes and may support the deletion of false-positive predictions. Joining mouse and human as the cross-comparison dataset for the first two mammals are: two Drosophila species, D. melanogaster and D. pseudoobscura; two sea squirts, Ciona intestinalis and Ciona savignyi; four yeast (Saccharomyces species; two nematodes, Caenorhabditis elegans and Caenorhabditis briggsae; and two pufferfish (Takefugu rubripes and Tetraodon nigroviridis. Even genomes like yeast and C. elegans, which have been known for more than five years, are now being significantly improved. Methods developed for yeast or nematodes will now be applied to mouse and human, and soon to additional mammals such as rat and dog, to identify all the mammalian protein-coding genes. Current large disparities between human Unigene predictions (127,835 genes and gene-scanning methods (45,000 genes still need to be resolved. This will be the challenge during the next few years.

  18. Isolation of polymorphic microsatellite loci for the marine invader Microcosmus squamiger (Ascidiacea).

    Science.gov (United States)

    Rius, Marc; Turon, Xavier; Pascual, Marta

    2008-11-01

    The ascidian Microcosmus squamiger is native to Australia and has recently spread worldwide. It has become a pest in some littoral communities within its introduced range. An enriched genomic library of M. squamiger resulted in a total of eight polymorphic loci that were genotyped in 20 individuals from a population within its introduced range, and 20 individuals more from a native population. The mean number of alleles per locus was 5.33 and mean observed heterozygosity was 0.432. No significant linkage disequilibrium was found among loci pairs. Significant genetic differentiation was observed between populations.

  19. A new species of the genus Rhopalaea (Class: Ascidiacea) from the Red Sea.

    Science.gov (United States)

    Shenkar, Noa

    2013-01-03

    During regular surveys and collection of ascidians along the Red Sea coast of Israel, several specimens of an undescribed species of Rhopalaea were collected. Samples were collected by SCUBA from the natural coral reef and man-made structures at depths between 10 to 40m. This is the first species of the genus Rhopalaea described from the Red Sea, which is characterized by a transparent, uncolored gelatinous tunic with elongated attachment extensions, and is distinguished by its eight atrial lobes, thoracic muscle arrangement, and branchial sac structure.

  20. Recruitment Variability of Coral Reef Sessile Communities of the Far North Great Barrier Reef.

    Science.gov (United States)

    Luter, Heidi M; Duckworth, Alan R; Wolff, Carsten W; Evans-Illidge, Elizabeth; Whalan, Steve

    2016-01-01

    One of the key components in assessing marine sessile organism demography is determining recruitment patterns to benthic habitats. An analysis of serially deployed recruitment tiles across depth (6 and 12 m), seasons (summer and winter) and space (meters to kilometres) was used to quantify recruitment assemblage structure (abundance and percent cover) of corals, sponges, ascidians, algae and other sessile organisms from the northern sector of the Great Barrier Reef (GBR). Polychaetes were most abundant on recruitment titles, reaching almost 50% of total recruitment, yet covered reefs.

  1. Recent Advances on the Total Syntheses of Communesin Alkaloids and Perophoramidine.

    Science.gov (United States)

    Trost, Barry M; Osipov, Maksim

    2015-11-09

    The communesin alkaloids are a diverse family of Penicillium-derived alkaloids. Their caged-polycyclic structure and intriguing biological profiles have made these natural products attractive targets for total synthesis. Similarly, the ascidian-derived alkaloid, perophoramidine, is structurally related to the communesins and has also become a popular target for total synthesis. This review serves to summarize the many elegant approaches that have been developed to access the communesin alkaloids and perophoramidine. Likewise, strategies to access the communesin ring system are reviewed.

  2. Haplostoma dudleyae sp. nov. (Cyclopoida: Ascidicolidae), parasitic in Eudistoma olivaceum from the Indian River in southern Florida

    Science.gov (United States)

    Ooishi, S.

    1998-06-01

    Haplostoma dudleyae sp. nov. is described and illustrated on the basis of females found in a compound ascidian ( Eudistoma olivaceum) collected from the Indian River in southern Florida, USA. Each parasitized zooid has a single female copepod. The egg sacs of the female are paired and, when laid, are almost U-shaped and folded against the dorsal side of the body. Haplostoma dudleyae and two other species ( H. canui Chatton and Harant, 1924, and H. humesi Ooishi, 1995) constitute a subgroup within the genus Haplostoma.

  3. Intracellular coagulation inhibits the extraction of proteins from Prochloron

    Science.gov (United States)

    Fall, R.; Lewin, R. A.; Fall, L. R.

    1983-01-01

    Protein extraction from the prokaryotic alga Prochloron LP (isolated from the ascidian host Lissoclinum patella) was complicated by an irreversible loss of cell fragility in the isolated algae. Accompanying this phenomenon, which is termed intracellular coagulation, was a redistribution of thylakoids around the cell periphery, a loss of photosynthetic O2 production, and a drastic decrease in the extractability of cell proteins. Procedures are described for the successful preparation and transport of cell extracts yielding the enzymes glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase as well as other soluble proteins.

  4. Small carnivores of Biligiri Rangaswamy Temple Tiger Reserve, Karnataka, India

    Directory of Open Access Journals (Sweden)

    Honnavalli N. Kumara

    2014-11-01

    Full Text Available During the present study in Biligiri Rangaswamy Temple Tiger Reserve (BRT, nine species of small carnivores viz., Jungle Cat Felis chaus, Rusty-spotted Cat Prionalilurus rubiginosus, Leopard Cat Prionailurus bengalensis, Small Indian Civet Viverricula indica, Asian Palm Civet Paradoxurus hermaphroditus, Striped-necked Mongoose Herpestes vitticollis, Ruddy Mongoose Herpestes smithii, Common Mongoose Herpestes edwardsii and Smooth-coated Otter Lutrogale perspicillata, were recorded using camera-trapping technique, transect walks, and night surveys. Vegetation type strongly influences the presence and abundance of each species. The most sightings of small carnivores occurred in dry deciduous forests. Among all the species, the Asian Palm Civet was the most abundant and was followed by the small Indian Civet. Compared to many other forests or regions in India, the sight records of the Rusty-spotted Cat were relatively higher in BRT. Although we were unable to use statistical methods to search for higher levels of interdependencies between forest types and small carnivore abundance, our study sheds light on patterns of small carnivore distribution in this unique habitat which bridges the Western Ghats and the Eastern Ghats.

  5. Marine reserves demonstrate trophic interactions across habitats.

    Science.gov (United States)

    Langlois, Timothy J; Anderson, Marti J; Babcock, Russell C; Kato, Shin

    2006-02-01

    Several infaunal bivalve taxa show patterns of decreased biomass in areas with higher densities of adjacent reef-associated predators (the snapper, Pagrus auratus and rock lobster, Jasus edwardsii). A caging experiment was used to test the hypothesis that patterns observed were caused by predation, using plots seeded with a known initial density of the bivalve Dosinia subrosea to estimate survivorship. The caging experiment was replicated at several sites inside and outside two highly protected marine reserves: predators are significantly more abundant inside these reserves. Survivorship in fully caged, partially caged and open plots were then compared at sites having either low (non reserve) or high (reserve) predator density. The highest rates of survivorship of the bivalve were found in caged plots inside reserves and in all treatments outside reserves. However, inside reserves, open and partially caged treatments exhibited low survivorship. It was possible to specifically attribute much of this mortality to predation by large rock lobsters, due to distinctive marks on the valves of dead D. subrosea. This suggests that predation by large rock lobster could indeed account for the distributional patterns previously documented for certain bivalve populations. Our results illustrate that protection afforded by marine reserves is necessary to investigate how depletion through fishing pressure can change the role of upper-level predators and trophic processes between habitats.

  6. Testing morphologically based phylogenetic theories within the cartilaginous fishes with molecular data, with special reference to the catshark family (Chondrichthyes; Scyliorhinidae) and the interrelationships within them.

    Science.gov (United States)

    Human, Brett A; Owen, E Patricia; Compagno, Leonard J V; Harley, Eric H

    2006-05-01

    A molecular phylogenetic investigation was conducted to examine phylogenetic relationships between various members of the catsharks (Chondrichthyes; Carcharhiniformes; Scyliorhinidae), and is the largest chondrichthyan data set yet analysed, consisting of nearly 130,000 nucleotides. Three mitochondrial DNA genes were used to construct the phylogenies, cytochrome b, NADH-2, and NADH-4, with 41 sequences from 18 taxa being novel. These sequences were either used separately or combined into a single data set, and phylogenies were constructed using various methods, however, only the Bayesian inference tree derived from the cytochrome b data set was resolved sufficiently for phylogenetic inferences to be made. Interestingly, the family Scyliorhinidae was not supported by the results and was found to be paraphyletic. The Scyliorhininae and Pentanchinae were supported, whereas the Pentanchini clade was present, but not well supported. The Halaelurini hypothesis was supported with Holohalaelurus identified as the basal genus of that clade, and Haploblepharus edwardsii identified as the basal taxon for that genus. Elsewhere within the Chondrichthyes, the Carcharhiniformes and the Lamniformes were found to be monophyletic, and the Heterodontiformes was placed within the Squalimorphs. The placement of the skates and rays in these analyses support the Batoidea as being sister to the Elasmobranchii.

  7. Vertical distribution and seasonality of peracarid crustaceans associated with intertidal macroalgae

    Science.gov (United States)

    Guerra-García, J. M.; Baeza-Rojano, E.; Cabezas, M. P.; García-Gómez, J. C.

    2011-02-01

    Spatial patterns and seasonal fluctuations of intertidal peracarids from Tarifa Island, Strait of Gibraltar, were studied over a two-year period (December 2005-December 2007). A total of 25,749 individuals were collected, comprising 46 species. Amphipods were best represented in the total number of species (32) and individuals (89% of numerical abundance) followed by isopods (12 species and 11% abundance) and tanaids (2 species and 1%). The highest number of species was registered in intermediate levels (1-1.5 m) dominated by Corallina elongata, although the highest abundances of peracarids were associated to seaweeds of lower levels (0-1 m) such as Gelidium corneum, Osmundea pinnatifida, Valonia utricularis and a turf of Caulacanthus ustulatus. The most abundant peracarids, Hyale stebbingi, H. schmidti, H. perieri, Stenothoe monoculoides, Caprella penantis, C. grandimana, Dynamene edwardsii and Ischyromene lacazei, were present throughout the whole year during 2006 and 2007. The highest peracarid densities were measured in April-August coinciding with the highest development of seaweeds, just before the maximum values of water temperature measured at the end of summer. Multivariate analyses confirmed a clear zonation of algae and associated peracarids in a vertical gradient, which was maintained stable during the two-year study. Several physical and biological factors may regulate such patterns of peracarid abundance and future experimental studies are necessary to explore the importance of factors such as competition, predation or weather conditions.

  8. Asentamiento diario de megalopas de jaibas del género Cancer en un estuario micromareal Daily settlement of Cancer crab megalopae in a microtidal estuary

    Directory of Open Access Journals (Sweden)

    Luis Miguel Pardo

    2012-03-01

    Full Text Available El asentamiento de crustáceos decápodos en ambientes estuarinos, es la última etapa de un complejo proceso en que las especies meroplanctónicas cierran la fase de vida pelágica. Este proceso tiene etapas sucesivas, que comienza con la formación de parches larvales frente a la costa, su transporte hacia las zonas de crianza, exploración de sustrato en busca de un lugar adecuado para el asentamiento y la metamorfosis a juvenil. Las interacciones entre los factores físicos y el comportamiento de las larvas competentes regulan las diversas etapas de este proceso, determinando finalmente las tasas de asentamiento locales. En este estudio se analiza la importancia relativa de las forzantes físicas que actúan a meso-escala (i.e. estrés del viento, nivel del mar y caudal del río y micro-escala (condiciones locales de temperatura, salinidad y tipo de sustrato sobre el asentamiento de megalopas de los braquiuros Cancer edwardsii y C. coronatus, principales jaibas comerciales en la pesca artesanal chilena. Para esto se instalaron colectores larvales pasivos de fondo por 73 días consecutivos en el periodo de máximo reclutamiento (i.e. abundancia de juvenil I, en la desembocadura del estuario del río Valdivia y se dispuso de arena gruesa y un símil de tapiz algal como sustrato. Los resultados mostraron que: a el asentamiento está caracterizado por extensos periodos de escasos asentados alternados por pulsos de máximos, que no necesariamente coinciden entre las especies estudiadas, b el asentamiento de C. edwardsii mostró estar relacionado con múltiples forzantes que generan la advección de aguas cálidas hacia la costa, c el asentamiento de C. coronatus tuvo relación con las forzantes que generan la surgencia costera, d las larvas de ambas especies no difieren en el asentamiento sobre sustratos heterogéneos. Este estudio mostró que los patrones de asentamiento larval son especie específicos, incluso en especies simpátricas y

  9. Overfishing reduces resilience of kelp beds to climate-driven catastrophic phase shift.

    Science.gov (United States)

    Ling, S D; Johnson, C R; Frusher, S D; Ridgway, K R

    2009-12-29

    A key consideration in assessing impacts of climate change is the possibility of synergistic effects with other human-induced stressors. In the ocean realm, climate change and overfishing pose two of the greatest challenges to the structure and functioning of marine ecosystems. In eastern Tasmania, temperate coastal waters are warming at approximately four times the global ocean warming average, representing the fastest rate of warming in the Southern Hemisphere. This has driven range extension of the ecologically important long-spined sea urchin (Centrostephanus rodgersii), which has now commenced catastrophic overgrazing of productive Tasmanian kelp beds leading to loss of biodiversity and important rocky reef ecosystem services. Coincident with the overgrazing is heavy fishing of reef-based predators including the spiny lobster Jasus edwardsii. By conducting experiments inside and outside Marine Protected Areas we show that fishing, by removing large predatory lobsters, has reduced the resilience of kelp beds against the climate-driven threat of the sea urchin and thus increased risk of catastrophic shift to widespread sea urchin barrens. This shows that interactions between multiple human-induced stressors can exacerbate nonlinear responses of ecosystems to climate change and limit the adaptive capacity of these systems. Management actions focused on reducing the risk of catastrophic phase shift in ecosystems are particularly urgent in the face of ongoing warming and unprecedented levels of predator removal from the world's oceans.

  10. A mongoose remain (Mammalia: Carnivora) from the Upper Irrawaddy sediments, Myanmar and its significance in evolutionary history of Asian herpestids

    Science.gov (United States)

    Egi, Naoko; Thaung-Htike; Zin-Maung-Maung-Thein; Maung-Maung; Nishioka, Yuichiro; Tsubamoto, Takehisa; Ogino, Shintaro; Takai, Masanaru

    2011-11-01

    A tooth of a mongoose (Mammalia: Carnivora: Herpestidae) was discovered from the Upper Irrawaddy sediments in central Myanmar. The age of the fauna is not older than the mid-Pliocene. It is identified as a right first upper molar of a small species of Urva (formally included in the genus Herpestes) based on its size and shape. The present specimen is the first carnivoran from the Upper Irrawaddy sediments and is the first record of mongooses in the Pliocene and early Pleistocene of Asia. It confirms that mongooses had already dispersed into Southeast Asia by the late Pliocene, being consistent with the previous molecular phylogenetic analyses. The fossil may belong to one of the extant species, but an assignment to a specific species is difficult due to the fragmentary nature of the specimen and the small interspecific differences in dental shape among the Asian mongooses. The size of the tooth suggests that the Irrawaddy specimen is within or close to the clade of Urva auropunctata + javanica + edwardsii, and this taxonomic assignment agrees with the geographical distribution.

  11. Ecotoxicological evaluation of polycyclic aromatic hydrocarbons using marine invertebrate embryo-larval bioassays.

    Science.gov (United States)

    Bellas, Juan; Saco-Alvarez, Liliana; Nieto, Oscar; Beiras, Ricardo

    2008-01-01

    The toxicity of polycyclic aromatic hydrocarbons (PAHs) was determined using mussel, sea-urchin and ascidian embryo-larval bioassays. Fluorescent light exposure enhanced phenanthrene, fluoranthene, pyrene and hydroxypyrene toxicity in comparison with dark conditions, but not naphthalene and fluorene toxicity. The toxicity of PAHs was inversely related to their K(OW) values following QSAR models derived for baseline toxicity of general narcotics, whereas the obtained regression using toxicity data from photoactivated PAHs significantly departed from the general narcosis model. Also, the mixture toxicity of five PAHs to the larval growth of the sea-urchin was compared with predictions derived from the concentration addition concept, indicating less than additive effects. Finally, we compared our toxicity data with worst-case environmental concentrations in order to provide a preliminary estimate of the risk to the marine environment. Naphthalene, fluorene and pyrene are not considered to pose a risk to sea-urchin, mussel or ascidian larvae, whilst phenanthrene and fluoranthene may pose a risk for mussel and sea-urchin. Moreover, a higher risk for those species is expected when we consider the photoactivation of the PAHs.

  12. Cyanobacterial diversity and a new acaryochloris-like symbiont from Bahamian sea-squirts.

    Directory of Open Access Journals (Sweden)

    Susanna López-Legentil

    Full Text Available Symbiotic interactions between ascidians (sea-squirts and microbes are poorly understood. Here we characterized the cyanobacteria in the tissues of 8 distinct didemnid taxa from shallow-water marine habitats in the Bahamas Islands by sequencing a fragment of the cyanobacterial 16S rRNA gene and the entire 16S-23S rRNA internal transcribed spacer region (ITS and by examining symbiont morphology with transmission electron (TEM and confocal microscopy (CM. As described previously for other species, Trididemnum spp. mostly contained symbionts associated with the Prochloron-Synechocystis group. However, sequence analysis of the symbionts in Lissoclinum revealed two unique clades. The first contained a novel cyanobacterial clade, while the second clade was closely associated with Acaryochloris marina. CM revealed the presence of chlorophyll d (chl d and phycobiliproteins (PBPs within these symbiont cells, as is characteristic of Acaryochloris species. The presence of symbionts was also observed by TEM inside the tunic of both the adult and larvae of L. fragile, indicating vertical transmission to progeny. Based on molecular phylogenetic and microscopic analyses, Candidatus Acaryochloris bahamiensis nov. sp. is proposed for this symbiotic cyanobacterium. Our results support the hypothesis that photosymbiont communities in ascidians are structured by host phylogeny, but in some cases, also by sampling location.

  13. Vanadium-Binding Ability of Nucleoside Diphosphate Kinase from the Vanadium-Rich Fan Worm, Pseudopotamilla occelata.

    Science.gov (United States)

    Yamaguchi, Nobuo; Yoshinaga, Masafumi; Kamino, Kei; Ueki, Tatsuya

    2016-06-01

    Polychaete fan worms and ascidians accumulate high levels of vanadium ions. Several vanadiumbinding proteins, known as vanabins, have been found in ascidians. However, no vanadium-binding factors have been isolated from the fan worm. In the present study, we sought to identify vanadiumbinding proteins in the branchial crown of the fan worm using immobilized metal ion affinity chromatography. A nucleoside diphosphate kinase (NDK) homolog was isolated and determined to be a vanadium-binding protein. Kinase activity of the NDK homologue, PoNDK, was suppressed by the addition of V(IV), but was unaffected by V(V). The effect of V(IV) on PoNDK precedes its activation by Mg(II). This is the first report to describe the relationship between NDK and V(IV). PoNDK is located in the epidermis of the branchial crown, and its distribution is very similar to that of vanadium. These results suggest that PoNDK is associated with vanadium accumulation and metabolism in P. occelata.

  14. La influencia de la convivencia escolar en el nivel de inclusión educativa, en estudiantes de bachiller

    Directory of Open Access Journals (Sweden)

    MSc. Rolando Medina Peña

    2016-04-01

    Full Text Available La inclusión educativa muchas veces no es bien entendida y se interpreta de diversas formas en el mundo. Desde el campo educativo se connota, a la manera en que la ins­titución educacional da respuesta a la diversidad y, tiene relación directa con el término necesidades educativas es­peciales (NEE. La investigación examina la influencia del código de convivencia escolar en el nivel de inclusión edu­cativa, a partir de la asunción de las necesidades educati­vas especiales de algunos de sus estudiantes. Se perfec­ciona la comprensión de las NEE, de inclusión educativa y los recursos educativos que se ajustan a las peculiaridades del desarrollo humano.

  15. AcEST: DK957108 [AcEST

    Lifescience Database Archive (English)

    Full Text Available ase 39.9) Link to BlastX Result : TrEMBL tr_hit_id A7R8E7 Definition tr|A7R8E7|A7R8E7_VITVI Chromosome undetermined... alignments: (bits) Value tr|A7R8E7|A7R8E7_VITVI Chromosome undetermined scaffold_2493, wh... 135 2e-30 tr|A...7QZU9|A7QZU9_VITVI Chromosome undetermined scaffold_288, who... 135 2e-30 tr|A7QZ...ein OS=Vitis... 94 8e-18 tr|A7QTI9|A7QTI9_VITVI Chromosome undetermined scaffold_...L83_CIOIN Zinc finger protein OS=Ciona intestinalis... 34 9.4 >tr|A7R8E7|A7R8E7_VITVI Chromosome undetermined

  16. Early Chordate Origins of the Vertebrate Second Heart Field

    Science.gov (United States)

    Stolfi, Alberto; Gainous, T. Blair; Young, John J.; Mori, Alessandro; Levine, Michael; Christiaen, Lionel

    2016-01-01

    The vertebrate heart is formed from diverse embryonic territories, including the first and second heart fields. The second heart field (SHF) gives rise to the right ventricle and outflow tract, yet its evolutionary origins are unclear. We found that heart progenitor cells of the simple chordate Ciona intestinalis also generate precursors of the atrial siphon muscles (ASMs). These precursors express Islet and Tbx1/10, evocative of the splanchnic mesoderm that produces the lower jaw muscles and SHF of vertebrates. Evidence is presented that the transcription factor COE is a critical determinant of ASM fate. We propose that the last common ancestor of tunicates and vertebrates possessed multipotent cardiopharyngeal muscle precursors, and that their reallocation might have contributed to the emergence of the SHF. PMID:20671188

  17. La mente mecánica

    OpenAIRE

    Suay Belenguer, Juan Miguel

    2012-01-01

    La mente humana es capaz de razonar, de manera similar que lo haría un ordenador, sobre cuestiones que son formuladas algorítmicamente, pero tam¬bién es capaz de realizar otras funciones que algunos autores consideran que son imposibles de simular por una máquina. Los diferentes respuestas a cómo fun-ciona la mente han sido abordadas por la filosofía de la mente, la lógica, la psico-logía y la neurología, incluso hoy en día por la mecánica cuántica. En este trabajo intentaré realizar un compe...

  18. Monitoring biofouling communities could reduce impacts to mussel aquaculture by allowing synchronisation of husbandry techniques with peaks in settlement.

    Science.gov (United States)

    Sievers, Michael; Dempster, Tim; Fitridge, Isla; Keough, Michael J

    2014-02-01

    Fouling organisms in bivalve aquaculture cause significant economic losses for the industry. Managing biofouling is typically reactive, and involves time- and labour-intensive removal techniques. Mussel spat settlement and biofouling were documented over 20 months at three mussel farms within Port Phillip Bay (PPB), Australia to determine if knowledge of settlement patterns could assist farmers in avoiding biofouling. Mussel spat settlement was largely confined to a 2-month period at one farm. Of the problematic foulers, Ectopleura crocea settlement varied in space and time at all three farms, whilst Ciona intestinalis and Pomatoceros taeniata were present predominantly at one farm and exhibited more distinct settlement periods. Within PPB, complete avoidance of biofouling is impossible. However, diligent monitoring may help farmers avoid peaks in detrimental biofouling species and allow them to implement removal strategies such as manual cleaning, and postpone grading and re-socking practices, until after these peaks.

  19. Dicty_cDB: Contig-U09124-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available EST_lsal_evj_936284 lsalevj mixed_tissue_mixed_st... 62 2e-09 2 ( DR713622 ) Le_lv0_06c01_SP6 Little Skate L...iver, Normalized L... 64 2e-09 2 ( DR713276 ) Le_lv0_02a12_SP6 Little Skate Liver, Normalized L... 64 2e-09 ...2 ( DR713314 ) Le_lv0_02e09_SP6 Little Skate Liver, Normalized L... 64 2e-09 2 ( ... librar... 64 4e-10 2 ( BW031100 ) Ciona intestinalis cDNA, clone:cibd017e13, 5' end... 64 4e-10 2 ( DR713623 ) Le_lv0_06c02_SP6 Litt...le Skate Liver, Normalized L... 64 2e-09 2 ( FK922007 )

  20. Reciprocal and dynamic polarization of planar cell polarity core components and myosin.

    Science.gov (United States)

    Newman-Smith, Erin; Kourakis, Matthew J; Reeves, Wendy; Veeman, Michael; Smith, William C

    2015-04-13

    The Ciona notochord displays planar cell polarity (PCP), with anterior localization of Prickle (Pk) and Strabismus (Stbm). We report that a myosin is polarized anteriorly in these cells and strongly colocalizes with Stbm. Disruption of the actin/myosin machinery with cytochalasin or blebbistatin disrupts polarization of Pk and Stbm, but not of myosin complexes, suggesting a PCP-independent aspect of myosin localization. Wash out of cytochalasin restored Pk polarization, but not if done in the presence of blebbistatin, suggesting an active role for myosin in core PCP protein localization. On the other hand, in the pk mutant line, aimless, myosin polarization is disrupted in approximately one third of the cells, indicating a reciprocal action of core PCP signaling on myosin localization. Our results indicate a complex relationship between the actomyosin cytoskeleton and core PCP components in which myosin is not simply a downstream target of PCP signaling, but also required for PCP protein localization.

  1. Brachyury, Foxa2 and the cis-Regulatory Origins of the Notochord.

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    Diana S José-Edwards

    2015-12-01

    Full Text Available A main challenge of modern biology is to understand how specific constellations of genes are activated to differentiate cells and give rise to distinct tissues. This study focuses on elucidating how gene expression is initiated in the notochord, an axial structure that provides support and patterning signals to embryos of humans and all other chordates. Although numerous notochord genes have been identified, the regulatory DNAs that orchestrate development and propel evolution of this structure by eliciting notochord gene expression remain mostly uncharted, and the information on their configuration and recurrence is still quite fragmentary. Here we used the simple chordate Ciona for a systematic analysis of notochord cis-regulatory modules (CRMs, and investigated their composition, architectural constraints, predictive ability and evolutionary conservation. We found that most Ciona notochord CRMs relied upon variable combinations of binding sites for the transcription factors Brachyury and/or Foxa2, which can act either synergistically or independently from one another. Notably, one of these CRMs contains a Brachyury binding site juxtaposed to an (AC microsatellite, an unusual arrangement also found in Brachyury-bound regulatory regions in mouse. In contrast, different subsets of CRMs relied upon binding sites for transcription factors of widely diverse families. Surprisingly, we found that neither intra-genomic nor interspecific conservation of binding sites were reliably predictive hallmarks of notochord CRMs. We propose that rather than obeying a rigid sequence-based cis-regulatory code, most notochord CRMs are rather unique. Yet, this study uncovered essential elements recurrently used by divergent chordates as basic building blocks for notochord CRMs.

  2. Do settlement dynamics influence competitive interactions between an alien tunicate and its native congener?

    Science.gov (United States)

    Bouchemousse, Sarah; Lévêque, Laurent; Viard, Frédérique

    2017-01-01

    Variation in density of early stages, that is, larvae and juveniles, is a major determinant of the distribution and abundance of the adult population of most marine invertebrates. These early stages thus play a key role in competitive interactions, and, more specifically, in invasion dynamics when biologically similar native and non-native species (NNS) come into contact in the same habitat. We examined the settlement dynamics and settlement rate of two important members of the fouling community that are common on human-made infrastructures around the world: Ciona robusta (formerly known as Ciona intestinalis type A) and C. intestinalis (formerly known as C. intestinalis type B). In the western English Channel, the two species live in close syntopy following the recent introduction of C. robusta in the native European range of C. intestinalis. Using settlement panels replaced monthly over 2 years in four marinas (including one studied over 4 years) and species-diagnostic molecular markers to distinguish between juveniles of both species (N = 1,650), we documented similar settlement dynamics of both species, with two settlement periods within a calendar year. With one exception, settlement times were highly similar in the congeners. Although the NNS showed lower settlement density than that of the native congener, its juvenile recruitment was high during the second settlement period that occurs after the warm season, a pattern also observed in adult populations. Altogether, our results suggest that species' settlement dynamics do not lead to the dominance of one species over the other through space monopolization. In addition, we showed that changes over time are more pronounced in the NNS than in the native species. This is possibly due to a higher sensitivity of the NNS to changes of environmental factors such as temperature and salinity. Environmental changes may thus eventually modify the strength of competitive interactions between the two species as

  3. Parallel evolution of chordate cis-regulatory code for development.

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    Laura Doglio

    2013-11-01

    Full Text Available Urochordates are the closest relatives of vertebrates and at the larval stage, possess a characteristic bilateral chordate body plan. In vertebrates, the genes that orchestrate embryonic patterning are in part regulated by highly conserved non-coding elements (CNEs, yet these elements have not been identified in urochordate genomes. Consequently the evolution of the cis-regulatory code for urochordate development remains largely uncharacterised. Here, we use genome-wide comparisons between C. intestinalis and C. savignyi to identify putative urochordate cis-regulatory sequences. Ciona conserved non-coding elements (ciCNEs are associated with largely the same key regulatory genes as vertebrate CNEs. Furthermore, some of the tested ciCNEs are able to activate reporter gene expression in both zebrafish and Ciona embryos, in a pattern that at least partially overlaps that of the gene they associate with, despite the absence of sequence identity. We also show that the ability of a ciCNE to up-regulate gene expression in vertebrate embryos can in some cases be localised to short sub-sequences, suggesting that functional cross-talk may be defined by small regions of ancestral regulatory logic, although functional sub-sequences may also be dispersed across the whole element. We conclude that the structure and organisation of cis-regulatory modules is very different between vertebrates and urochordates, reflecting their separate evolutionary histories. However, functional cross-talk still exists because the same repertoire of transcription factors has likely guided their parallel evolution, exploiting similar sets of binding sites but in different combinations.

  4. Fishery induces sperm depletion and reduction in male reproductive potential for crab species under male-biased harvest strategy.

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    Luis Miguel Pardo

    Full Text Available Sperm depletion in males can occur when polygynous species are intensively exploited under a male-biased management strategy. In fisheries involving crabs species, the effects of this type of management on the reproductive potential is far from being understood. This study tests whether male-biased management of the principal Chilean crab fishery is able to affect the potential capacity of Metacarcinus edwardsii males to transfer sperm to females. Five localities in southern Chile, recording contrasting crab fishery landing, were selected to assess the potential of sperm depletion triggered by fishery. Seasonally, male crabs from each locality were obtained. Dry weight and histological condition of vasa deferentia and the Vaso-Somatic Index (VSI were determined in order to use them as proxies for sperm depletion and male reproductive condition. A manipulative experiment was performed in the laboratory to estimate vasa deferentia weight and VSI from just-mated males in order to obtain a reference point for the potential effects of the fishery on sperm reserves. Sperm storage capacity is significantly affected by fisheries; during the mating season vasa deferentia from localities with low fishery intensity were heavier than those from high intensity fisheries, and these differences were even more evident in large males. Histological section showed that this disparity in vasa deferentia weight was explained principally by differences in the quantity of spermatophores rather than other seminal material. VSI was always higher in males from localities with low fishery intensity. Males from localities with high fishery intensity showed little capacity to recover sperm reserves and the VSI of these males remained below the values of the just-mated males. Detriment in the capacity of males to transfer sperm is the first step to sperm limitation in an exploited population, thus detection of sperm depletion can be an alert to introduce changes in the

  5. Effects of near-future ocean acidification, fishing, and marine protection on a temperate coastal ecosystem.

    Science.gov (United States)

    Cornwall, Christopher E; Eddy, Tyler D

    2015-02-01

    Understanding ecosystem responses to global and local anthropogenic impacts is paramount to predicting future ecosystem states. We used an ecosystem modeling approach to investigate the independent and cumulative effects of fishing, marine protection, and ocean acidification on a coastal ecosystem. To quantify the effects of ocean acidification at the ecosystem level, we used information from the peer-reviewed literature on the effects of ocean acidification. Using an Ecopath with Ecosim ecosystem model for the Wellington south coast, including the Taputeranga Marine Reserve (MR), New Zealand, we predicted ecosystem responses under 4 scenarios: ocean acidification + fishing; ocean acidification + MR (no fishing); no ocean acidification + fishing; no ocean acidification + MR for the year 2050. Fishing had a larger effect on trophic group biomasses and trophic structure than ocean acidification, whereas the effects of ocean acidification were only large in the absence of fishing. Mortality by fishing had large, negative effects on trophic group biomasses. These effects were similar regardless of the presence of ocean acidification. Ocean acidification was predicted to indirectly benefit certain species in the MR scenario. This was because lobster (Jasus edwardsii) only recovered to 58% of the MR biomass in the ocean acidification + MR scenario, a situation that benefited the trophic groups lobsters prey on. Most trophic groups responded antagonistically to the interactive effects of ocean acidification and marine protection (46%; reduced response); however, many groups responded synergistically (33%; amplified response). Conservation and fisheries management strategies need to account for the reduced recovery potential of some exploited species under ocean acidification, nonadditive interactions of multiple factors, and indirect responses of species to ocean acidification caused by declines in calcareous predators.

  6. A quantitative metric to identify critical elements within seafood supply networks.

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    Éva E Plagányi

    Full Text Available A theoretical basis is required for comparing key features and critical elements in wild fisheries and aquaculture supply chains under a changing climate. Here we develop a new quantitative metric that is analogous to indices used to analyse food-webs and identify key species. The Supply Chain Index (SCI identifies critical elements as those elements with large throughput rates, as well as greater connectivity. The sum of the scores for a supply chain provides a single metric that roughly captures both the resilience and connectedness of a supply chain. Standardised scores can facilitate cross-comparisons both under current conditions as well as under a changing climate. Identification of key elements along the supply chain may assist in informing adaptation strategies to reduce anticipated future risks posed by climate change. The SCI also provides information on the relative stability of different supply chains based on whether there is a fairly even spread in the individual scores of the top few key elements, compared with a more critical dependence on a few key individual supply chain elements. We use as a case study the Australian southern rock lobster Jasus edwardsii fishery, which is challenged by a number of climate change drivers such as impacts on recruitment and growth due to changes in large-scale and local oceanographic features. The SCI identifies airports, processors and Chinese consumers as the key elements in the lobster supply chain that merit attention to enhance stability and potentially enable growth. We also apply the index to an additional four real-world Australian commercial fishery and two aquaculture industry supply chains to highlight the utility of a systematic method for describing supply chains. Overall, our simple methodological approach to empirically-based supply chain research provides an objective method for comparing the resilience of supply chains and highlighting components that may be critical.

  7. The good, the bad and the recovery in an assisted migration.

    Directory of Open Access Journals (Sweden)

    Bridget S Green

    Full Text Available BACKGROUND: Assisted migration or translocation of species to ameliorate effects of habitat loss or changing environment is currently under scrutiny as a conservation tool. A large scale experiment of assisted migration over hundreds of kilometres was tested on a morph from a commercial fishery of southern rock lobster Jasus edwardsii, to enhance depleted populations, improve the yield and sustainability of the fishery, and test resilience to a changing climate. METHODOLOGY AND PRINCIPAL FINDINGS: Approximately 10,000 lower-valued, pale-coloured lobsters were moved from deep water to inshore sites (2 in Tasmania [TAS] and 2 in South Australia [SA] where the high-value, red morph occurs. In TAS this was a northwards movement of 1° latitude. Growth was measured only in TAS lobsters, and reproductive status was recorded in lobsters from all locations. Pale females (TAS grew 4 times faster than resident pale lobsters from the original site and twice as fast as red lobsters at their new location. Approximately 30% of translocated pale lobsters deferred reproduction for one year after release (SA and TAS, and grew around 1 mm yr(-1 less compared to translocated pale lobsters that did not defer reproduction. In spite of this stress response to translocation, females that deferred reproduction still grew 2-6 mm yr(-1 more than lobsters at the source site. Lobsters have isometric growth whereby volume increases as a cube of length. Consequently despite the one-year hiatus in reproduction, increased growth increases fecundity of translocated lobsters, as the increase in size provided a larger volume for producing and incubating eggs in future years. CONCLUSIONS AND SIGNIFICANCE: Assisted migration improved egg production and growth, despite a temporary stress response, and offers a tool to improve the production, sustainability and resilience of the fishery.

  8. A quantitative metric to identify critical elements within seafood supply networks.

    Science.gov (United States)

    Plagányi, Éva E; van Putten, Ingrid; Thébaud, Olivier; Hobday, Alistair J; Innes, James; Lim-Camacho, Lilly; Norman-López, Ana; Bustamante, Rodrigo H; Farmery, Anna; Fleming, Aysha; Frusher, Stewart; Green, Bridget; Hoshino, Eriko; Jennings, Sarah; Pecl, Gretta; Pascoe, Sean; Schrobback, Peggy; Thomas, Linda

    2014-01-01

    A theoretical basis is required for comparing key features and critical elements in wild fisheries and aquaculture supply chains under a changing climate. Here we develop a new quantitative metric that is analogous to indices used to analyse food-webs and identify key species. The Supply Chain Index (SCI) identifies critical elements as those elements with large throughput rates, as well as greater connectivity. The sum of the scores for a supply chain provides a single metric that roughly captures both the resilience and connectedness of a supply chain. Standardised scores can facilitate cross-comparisons both under current conditions as well as under a changing climate. Identification of key elements along the supply chain may assist in informing adaptation strategies to reduce anticipated future risks posed by climate change. The SCI also provides information on the relative stability of different supply chains based on whether there is a fairly even spread in the individual scores of the top few key elements, compared with a more critical dependence on a few key individual supply chain elements. We use as a case study the Australian southern rock lobster Jasus edwardsii fishery, which is challenged by a number of climate change drivers such as impacts on recruitment and growth due to changes in large-scale and local oceanographic features. The SCI identifies airports, processors and Chinese consumers as the key elements in the lobster supply chain that merit attention to enhance stability and potentially enable growth. We also apply the index to an additional four real-world Australian commercial fishery and two aquaculture industry supply chains to highlight the utility of a systematic method for describing supply chains. Overall, our simple methodological approach to empirically-based supply chain research provides an objective method for comparing the resilience of supply chains and highlighting components that may be critical.

  9. Radioimmunoassay in Ascidiella aspersa of a gonadoliberin (GnRH)-like factor with an apparent molecular weight higher than that of mammalian decapeptide

    Energy Technology Data Exchange (ETDEWEB)

    Dufour, S.; Monniot, F.; Monniot, C. and others

    1988-02-21

    A radioimmunoassay (RIA) for mammalian gonadoliberin (mGnRH) showed the presence of a GnRH-like factor in the neural complex of a Protochordate, Ascidiella aspersa (about 0.6 pg eq mGnRH/complex). The slope of the displacement curves was slightly lower than with mGnRH indicating antigene differences. No cross reactive material was found in mantle and siphonal area. The KD on Sephadex G25 was 0.45 versus 0.90 with mGnRH. That suggests that the molecular weight of the Ascidian GnRH-like factor is higher than that of known Vertebrate GnRH's, possibly due to a different processing of the precursor.

  10. Clinical marine toxicology: a European perspective for clinical toxicologists and poison centers.

    Science.gov (United States)

    Schmitt, Corinne; De Haro, Luc

    2013-08-02

    Clinical marine toxicology is a rapidly changing area. Many of the new discoveries reported every year in Europe involve ecological disturbances--including global warming--that have induced modifications in the chorology, behavior, and toxicity of many species of venomous or poisonous aquatic life including algae, ascidians, fish and shellfish. These changes have raised a number of public issues associated, e.g., poisoning after ingestion of contaminated seafood, envenomation by fish stings, and exposure to harmful microorganism blooms. The purpose of this review of medical and scientific literature in marine toxicology is to highlight the growing challenges induced by ecological disturbances that confront clinical toxicologists during the everyday job in the European Poison Centers.

  11. Clinical Marine Toxicology: A European Perspective for Clinical Toxicologists and Poison Centers

    Directory of Open Access Journals (Sweden)

    Luc De Haro

    2013-08-01

    Full Text Available Clinical marine toxicology is a rapidly changing area. Many of the new discoveries reported every year in Europe involve ecological disturbances—including global warming—that have induced modifications in the chorology, behavior, and toxicity of many species of venomous or poisonous aquatic life including algae, ascidians, fish and shellfish. These changes have raised a number of public issues associated, e.g., poisoning after ingestion of contaminated seafood, envenomation by fish stings, and exposure to harmful microorganism blooms. The purpose of this review of medical and scientific literature in marine toxicology is to highlight the growing challenges induced by ecological disturbances that confront clinical toxicologists during the everyday job in the European Poison Centers.

  12. [Distribution of Ecteinascidia turbinata (Ascidiacea: Perophoridae) in mangroves of the Yucatán Peninsula, Mexico].

    Science.gov (United States)

    Carballo, J L

    2000-01-01

    The ascidian Ecteinascidia turbinata synthesizes some of the most promising substances against solid-type tumors, but the only available source are the natural populations of this tunicate, which is reared or collected in different parts of the world. A total of 33 locations were sampled in the Gulf of Mexico and the Yucatan Peninsula. The tunicate was not found in Veracruz, Tabasco and Campeche, but it was well established on mangrove roots in the Yucatan Peninsula where we estimated densities more or less equal to one colony and an average production of 115 g of biomass per lineal meter of mangrove coastline in one location (Río Lagartos). Sustainable management appears to be possible.

  13. [Morphofunctional organization of reserve stem cells providing for asexual and sexual reproduction of invertebrates].

    Science.gov (United States)

    Isaeva, V V; Akhmadieva, A V; Aleksandriova, Ia N; Shukaliuk, A I

    2009-01-01

    Published and original data indicating evolutionary conservation of the morphofunctional organization of reserve stem cells providing for asexual and sexual reproduction of invertebrates are reviewed. Stem cells were studied in representatives of five animal types: archeocytes in sponge Oscarella malakhovi (Porifera), large interstitial cells in colonial hydroid Obelia longissima (Cnidaria), neoblasts in an asexual race of planarian Girardia tigrina (Platyhelmintes), stem cells in colonial rhizocephalans Peltogasterella gracilis, Polyascus polygenea, and Thylacoplethus isaevae (Arthropoda), and colonial ascidian Botryllus tuberatus (Chordata). Stem cells in animals of such diverse taxa feature the presence of germinal granules, are positive for proliferating cell nuclear antigen, demonstrate alkaline phosphatase activity (at marker of embryonic stem cells and primary germ cells in vertebrates), and rhizocephalan stem cells express the vasa-like gene (such genes are expressed in germline cells of different metazoans). The self-renewing pool of stem cells is the cellular basis of the reproductive strategy including sexual and asexual reproduction.

  14. Evaluation of the sea anemone Anthothoe albocincta as an augmentative biocontrol agent for biofouling on artificial structures.

    Science.gov (United States)

    Atalah, Javier; Bennett, Holly; Hopkins, Grant A; Forrest, Barrie M

    2013-01-01

    Augmentative biocontrol, defined as the use of indigenous natural enemies to control pest populations, has not been explored extensively in marine systems. This study tested the potential of the anemone Anthothoe albocincta as a biocontrol agent for biofouling on submerged artificial structures. Biofouling biomass was negatively related to anemone cover. Treatments with high anemone cover (>35%) led to significant changes in biofouling assemblages compared to controls. Taxa that contributed to these changes differed among sites, but included reductions in cover of problematic fouling organisms, such as solitary ascidians and bryozoans. In laboratory trials, A. albocincta substantially prevented the settlement of larvae of the bryozoan Bugula neritina when exposed to three levels of larval dose, suggesting predation as an important biocontrol mechanism, in addition to space pre-emption. This study demonstrated that augmentative biocontrol using anemones has the potential to reduce biofouling on marine artificial structures, although considerable further work is required to refine this tool before its application.

  15. Mycalamide A Shows Cytotoxic Properties and Prevents EGF-Induced Neoplastic Transformation through Inhibition of Nuclear Factors

    Science.gov (United States)

    Dyshlovoy, Sergey A.; Fedorov, Sergey N.; Kalinovsky, Anatoly I.; Shubina, Larisa K.; Bokemeyer, Carsten; Stonik, Valentin A.; Honecker, Friedemann

    2012-01-01

    Mycalamide A, a marine natural compound previously isolated from sponges, is known as a protein synthesis inhibitor with potent antitumor activity. However, the ability of this compound to prevent malignant transformation of cells has never been examined before. Here, for the first time, we report the isolation of mycalamide A from ascidian Polysincraton sp. as well as investigation of its cancer preventive properties. In murine JB6 Cl41 P+ cells, mycalamide A inhibited epidermal growth factor (EGF)-induced neoplastic transformation, and induced apoptosis at subnanomolar or nanomolar concentrations. The compound inhibited transcriptional activity of the oncogenic nuclear factors AP-1 and NF-κB, a potential mechanism of its cancer preventive properties. Induction of phosphorylation of the kinases MAPK p38, JNK, and ERK was also observed at high concentrations of mycalamide A. The drug shows promising potential for both cancer-prevention and cytotoxic therapy and should be further developed. PMID:22822368

  16. Developmental Control of Cell-Cycle Compensation Provides a Switch for Patterned Mitosis at the Onset of Chordate Neurulation.

    Science.gov (United States)

    Ogura, Yosuke; Sasakura, Yasunori

    2016-04-18

    During neurulation of chordate ascidians, the 11th mitotic division within the epidermal layer shows a posterior-to-anterior wave that is precisely coordinated with the unidirectional progression of the morphogenetic movement. Here we show that the first sign of this patterned mitosis is an asynchronous anterior-to-posterior S-phase length and that mitotic synchrony is reestablished by a compensatory asynchronous G2-phase length. Live imaging combined with genetic experiments demonstrated that compensatory G2-phase regulation requires transcriptional activation of the G2/M regulator cdc25 by the patterning genes GATA and AP-2. The downregulation of GATA and AP-2 at the onset of neurulation leads to loss of compensatory G2-phase regulation and promotes the transition to patterned mitosis. We propose that such developmentally regulated cell-cycle compensation provides an abrupt switch to spatially patterned mitosis in order to achieve the coordination between mitotic timing and morphogenesis.

  17. Cyanobactins from Cyanobacteria: Current Genetic and Chemical State of Knowledge

    Directory of Open Access Journals (Sweden)

    Joana Martins

    2015-11-01

    Full Text Available Cyanobacteria are considered to be one of the most promising sources of new, natural products. Apart from non-ribosomal peptides and polyketides, ribosomally synthesized and post-translationally modified peptides (RiPPs are one of the leading groups of bioactive compounds produced by cyanobacteria. Among these, cyanobactins have sparked attention due to their interesting bioactivities and for their potential to be prospective candidates in the development of drugs. It is assumed that the primary source of cyanobactins is cyanobacteria, although these compounds have also been isolated from marine animals such as ascidians, sponges and mollusks. The aim of this review is to update the current knowledge of cyanobactins, recognized as being produced by cyanobacteria, and to emphasize their genetic clusters and chemical structures as well as their bioactivities, ecological roles and biotechnological potential.

  18. Cyanobactins from Cyanobacteria: Current Genetic and Chemical State of Knowledge.

    Science.gov (United States)

    Martins, Joana; Vasconcelos, Vitor

    2015-11-13

    Cyanobacteria are considered to be one of the most promising sources of new, natural products. Apart from non-ribosomal peptides and polyketides, ribosomally synthesized and post-translationally modified peptides (RiPPs) are one of the leading groups of bioactive compounds produced by cyanobacteria. Among these, cyanobactins have sparked attention due to their interesting bioactivities and for their potential to be prospective candidates in the development of drugs. It is assumed that the primary source of cyanobactins is cyanobacteria, although these compounds have also been isolated from marine animals such as ascidians, sponges and mollusks. The aim of this review is to update the current knowledge of cyanobactins, recognized as being produced by cyanobacteria, and to emphasize their genetic clusters and chemical structures as well as their bioactivities, ecological roles and biotechnological potential.

  19. Screening Of Marine Bacteria For Pharmacological Activities

    Directory of Open Access Journals (Sweden)

    S. Vijayalakshmi

    2015-08-01

    Full Text Available Abstract The symbiotic and associated four marine bacteria BR1 Flavobacterium sp. isolated from Barnacle Balanus amphitriteEM13 Micrococus sp. from Seaweed Enteromorpha compressaPC4 Alcaligenes sp. from Ascidian Polyclinum constellatum and SW12 Bacillus sp. from seawater were cultured and extracted for pharmacological activities. The ethyl acetate extracts of these marine bacterial culture supernatants were screened for pharmacological activities such as Anti inflammatory Analgesic and CNS depressant activities using experimental animal model. In this studySW12 exhibited high activity for both Anti inflammatory and Analgesic. Especially which exhibited highest analgesic activity than standard drug pethidine. Another one PC4 showed highest analgesic activity similar to standard drug. Other two extracts EM13 and BR1 showed high activity in CNS depressant. Based on the result SW12 is a highly potent strain it may produce novel compound for pharmacological drug.

  20. Diversity of Nonribosomal Peptide Synthetase Genes in the Microbial Metagenomes of Marine Sponges

    Directory of Open Access Journals (Sweden)

    Ute Hentschel

    2012-05-01

    Full Text Available Genomic mining revealed one major nonribosomal peptide synthetase (NRPS phylogenetic cluster in 12 marine sponge species, one ascidian, an actinobacterial isolate and seawater. Phylogenetic analysis predicts its taxonomic affiliation to the actinomycetes and hydroxy-phenyl-glycine as a likely substrate. Additionally, a phylogenetically distinct NRPS gene cluster was discovered in the microbial metagenome of the sponge Aplysina aerophoba, which shows highest similarities to NRPS genes that were previously assigned, by ways of single cell genomics, to a Chloroflexi sponge symbiont. Genomic mining studies such as the one presented here for NRPS genes, contribute to on-going efforts to characterize the genomic potential of sponge-associated microbiota for secondary metabolite biosynthesis.

  1. Tunicate mitogenomics and phylogenetics: peculiarities of the Herdmania momus mitochondrial genome and support for the new chordate phylogeny

    Directory of Open Access Journals (Sweden)

    Loya Yossi

    2009-11-01

    Full Text Available Abstract Background Tunicates represent a key metazoan group as the sister-group of vertebrates within chordates. The six complete mitochondrial genomes available so far for tunicates have revealed distinctive features. Extensive gene rearrangements and particularly high evolutionary rates have been evidenced with regard to other chordates. This peculiar evolutionary dynamics has hampered the reconstruction of tunicate phylogenetic relationships within chordates based on mitogenomic data. Results In order to further understand the atypical evolutionary dynamics of the mitochondrial genome of tunicates, we determined the complete sequence of the solitary ascidian Herdmania momus. This genome from a stolidobranch ascidian presents the typical tunicate gene content with 13 protein-coding genes, 2 rRNAs and 24 tRNAs which are all encoded on the same strand. However, it also presents a novel gene arrangement, highlighting the extreme plasticity of gene order observed in tunicate mitochondrial genomes. Probabilistic phylogenetic inferences were conducted on the concatenation of the 13 mitochondrial protein-coding genes from representatives of major metazoan phyla. We show that whereas standard homogeneous amino acid models support an artefactual sister position of tunicates relative to all other bilaterians, the CAT and CAT+BP site- and time-heterogeneous mixture models place tunicates as the sister-group of vertebrates within monophyletic chordates. Moreover, the reference phylogeny indicates that tunicate mitochondrial genomes have experienced a drastic acceleration in their evolutionary rate that equally affects protein-coding and ribosomal-RNA genes. Conclusion This is the first mitogenomic study supporting the new chordate phylogeny revealed by recent phylogenomic analyses. It illustrates the beneficial effects of an increased taxon sampling coupled with the use of more realistic amino acid substitution models for the reconstruction of animal

  2. Sperm motility parameters and spermatozoa morphometric characterization in marine species: a study of swimmer and sessile species.

    Science.gov (United States)

    Gallego, V; Pérez, L; Asturiano, J F; Yoshida, M

    2014-09-15

    The biodiversity of marine ecosystems is diverse and a high number of species coexist side by side. However, despite the fact that most of these species share a common fertilization strategy, a high variability in terms of the size, shape, and motion of spermatozoa can be found. In this study, we have analyzed both the sperm motion parameters and the spermatozoa morphometric features of two swimmer (pufferfish and European eel) and two sessile (sea urchin and ascidian) marine species. The most important differences in the sperm motion parameters were registered in the swimming period. Sessile species sperm displayed notably higher values than swimmer species sperm. In addition, the sperm motilities and velocities of the swimmer species decreased sharply once the sperm was activated, whereas the sessile species were able to maintain their initial values for a long time. These results are linked directly to the species-specific lifestyles. Although sessile organisms, which show limited or no movement, need sperm with a capacity to swim for long distances to find the oocytes, swimmer organisms can move toward the female and release gametes near it, and therefore the spermatozoa does not need to swim for such a long time. At the same time, sperm morphology is related to sperm motion parameters, and in this study an in-depth morphometric analysis of ascidian, sea urchin, and pufferfish spermatozoa, using computer-assisted sperm analysis software, has been carried out for the first time. A huge variability in shapes, sizes, and structures of the studied species was found using electron microscopy.

  3. Real-time PCR detection of Didemnum perlucidum (Monniot, 1983) and Didemnum vexillum (Kott, 2002) in an applied routine marine biosecurity context.

    Science.gov (United States)

    Simpson, Tiffany J S; Dias, P Joana; Snow, Michael; Muñoz, Julieta; Berry, Tina

    2016-08-02

    Prevention and early detection are well recognized as the best strategies for minimizing the risks posed by nonindigenous species (NIS) that have the potential to become marine pests. Central to this is the ability to rapidly and accurately identify the presence of NIS, often from complex environmental samples like biofouling and ballast water. Molecular tools have been increasingly applied to assist with the identification of NIS and can prove particularly useful for taxonomically difficult groups like ascidians. In this study, we have developed real-time PCR assays suited to the specific identification of the ascidians Didemnum perlucidum and Didemnum vexillum. Despite being recognized as important global pests, this is the first time specific molecular detection methods have been developed that can support the early identification and detection of these species from a broad range of environmental sample types. These fast, robust and high-throughput assays represent powerful tools for routine marine biosecurity surveillance, as detection and confirmation of the early presence of species could assist in the timely establishment of emergency responses and control strategies. This study applied the developed assays to confirm the ability to detect Didemnid eDNA in water samples. While previous work has focused on detection of marine larvae from water samples, the development of real-time PCR assays specifically aimed at detecting eDNA of sessile invertebrate species in the marine environment represents a world first and a significant step forwards in applied marine biosecurity surveillance. Demonstrated success in the detection of D. perlucidum eDNA from water samples at sites where it could not be visually identified suggests value in incorporating such assays into biosecurity survey designs targeting Didemnid species.

  4. Evolution and origin of merlin, the product of the Neurofibromatosis type 2 (NF2 tumor-suppressor gene

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    Omelyanchuk Leonid V

    2005-12-01

    Full Text Available Abstract Background Merlin, the product of the Neurofibromatosis type 2 (NF2 tumor suppressor gene, belongs to the ezrin-radixin-moesin (ERM subgroup of the protein 4.1 superfamily, which links cell surface glycoproteins to the actin cytoskeleton. While merlin's functional activity has been examined in mammalian and Drosophila models, little is understood about its evolution, diversity, and overall distribution among different taxa. Results By combining bioinformatic and phylogenetic approaches, we demonstrate that merlin homologs are present across a wide range of metazoan lineages. While the phylogenetic tree shows a monophyletic origin of the ERM family, the origin of the merlin proteins is robustly separated from that of the ERM proteins. The derivation of merlin is thought to be in early metazoa. We have also observed the expansion of the ERM-like proteins within the vertebrate clade, which occurred after its separation from Urochordata (Ciona intestinalis. Amino acid sequence alignment reveals the absence of an actin-binding site in the C-terminal region of all merlin proteins from various species but the presence of a conserved internal binding site in the N-terminal domain of the merlin and ERM proteins. In addition, a more conserved pattern of amino acid residues is found in the region containing the so-called "Blue Box," although some amino acid substitutions in this region exist in the merlin sequences of worms, fish, and Ciona. Examination of sequence variability at functionally significant sites, including the serine-518 residue, the phosphorylation of which modulates merlin's intra-molecular association and function as a tumor suppressor, identifies several potentially important sites that are conserved among all merlin proteins but divergent in the ERM proteins. Secondary structure prediction reveals the presence of a conserved α-helical domain in the central to C-terminal region of the merlin proteins of various species. The

  5. Antibiotic, cytotoxic and enzyme inhibitory activity of crude extracts from Brazilian marine invertebrates Atividade antibiótica, citotóxica e de inibição enzimática de extratos brutos de invertebrados marinhos do Brasil

    Directory of Open Access Journals (Sweden)

    Mirna H. R. Seleghim

    2007-09-01

    Full Text Available Herein we present the results of a screening with 349 crude extracts of Brazilian marine sponges, ascidians, bryozoans and octocorals, against 16 strains of susceptible and antibiotic-resistant bacteria, one yeast (Candida albicans, Mycobacterium tuberculosis H37Rv, three cancer cell lines MCF-7 (breast, B16 (murine melanoma and HCT8 (colon, and Leishmania tarentolae adenine phosphoribosyl transferase (L-APRT enzyme. Less than 15% of marine sponge crude extracts displayed antibacterial activity, both against susceptible and antibiotic-resistant bacteria. Up to 40% of marine sponge crude extracts displayed antimycobacterial activity against M. tuberculosis H37Rv. Cytotoxicity was observed for 18% of marine sponge crude extracts. Finally, less than 3% of sponge extracts inhibited L-APRT. Less than 10% of ascidian crude extracts displayed antibacterial activity. More than 25% of ascidian crude extracts were active against M. tuberculosis and the three cancer cell lines. Only two crude extracts from the ascidian Polysyncraton sp. collected in different seasons (1995 and 1997 displayed activity against L-APRT. Less than 2% of bryozoan and octocoral crude extracts presented antibacterial activity, but a high percentage of crude extracts from bryozoan and octororal displayed cytotoxic (11% and 30%, respectively and antimycobacterial (60% activities. The extract of only one species of bryozoan, Bugula sp., presented inhibitory activity against L-APRT. Overall, the crude extracts of marine invertebrates herein investigated presented a high level of cytotoxic and antimycobacterial activities, a lower level of antibacterial activity and only a small number of crude extracts inhibited L-APRT. Taxonomic analysis of some of the more potently active crude extracts showed the occurrence of biological activity in taxa that have been previously chemically investigated. These include marine sponges belonging to genera Aaptos, Aplysina, Callyspongia, Haliclona

  6. The Foraging Ecology of the Endangered Cape Verde Shearwater, a Sentinel Species for Marine Conservation off West Africa.

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    Vitor H Paiva

    Full Text Available Large Marine Ecosystems such as the Canary Current system off West Africa sustains high abundance of small pelagic prey, which attracts marine predators. Seabirds are top predators often used as biodiversity surrogates and sentinel species of the marine ecosystem health, thus frequently informing marine conservation planning. This study presents the first data on the spatial (GPS-loggers and trophic (stable isotope analysis ecology of a tropical seabird-the endangered Cape Verde shearwater Calonectris edwardsii-during both the incubation and the chick-rearing periods of two consecutive years. This information was related with marine environmental predictors (species distribution models, existent areas of conservation concern for seabirds (i.e. marine Important Bird Areas; marine IBAs and threats to the marine environment in the West African areas heavily used by the shearwaters. There was an apparent inter-annual consistency on the spatial, foraging and trophic ecology of Cape Verde shearwater, but a strong alteration on the foraging strategies of adult breeders among breeding phases (i.e. from incubation to chick-rearing. During incubation, birds mostly targeted a discrete region off West Africa, known by its enhanced productivity profile and thus also highly exploited by international industrial fishery fleets. When chick-rearing, adults exploited the comparatively less productive tropical environment within the islands of Cape Verde, at relatively close distance from their breeding colony. The species enlarged its trophic niche and increased the trophic level of their prey from incubation to chick-rearing, likely to provision their chicks with a more diversified and better quality diet. There was a high overlap between the Cape Verde shearwaters foraging areas with those of European shearwater species that overwinter in this area and known areas of megafauna bycatch off West Africa, but very little overlap with existing Marine Important Bird

  7. The Foraging Ecology of the Endangered Cape Verde Shearwater, a Sentinel Species for Marine Conservation off West Africa.

    Science.gov (United States)

    Paiva, Vitor H; Geraldes, Pedro; Rodrigues, Isabel; Melo, Tommy; Melo, José; Ramos, Jaime A

    2015-01-01

    Large Marine Ecosystems such as the Canary Current system off West Africa sustains high abundance of small pelagic prey, which attracts marine predators. Seabirds are top predators often used as biodiversity surrogates and sentinel species of the marine ecosystem health, thus frequently informing marine conservation planning. This study presents the first data on the spatial (GPS-loggers) and trophic (stable isotope analysis) ecology of a tropical seabird-the endangered Cape Verde shearwater Calonectris edwardsii-during both the incubation and the chick-rearing periods of two consecutive years. This information was related with marine environmental predictors (species distribution models), existent areas of conservation concern for seabirds (i.e. marine Important Bird Areas; marine IBAs) and threats to the marine environment in the West African areas heavily used by the shearwaters. There was an apparent inter-annual consistency on the spatial, foraging and trophic ecology of Cape Verde shearwater, but a strong alteration on the foraging strategies of adult breeders among breeding phases (i.e. from incubation to chick-rearing). During incubation, birds mostly targeted a discrete region off West Africa, known by its enhanced productivity profile and thus also highly exploited by international industrial fishery fleets. When chick-rearing, adults exploited the comparatively less productive tropical environment within the islands of Cape Verde, at relatively close distance from their breeding colony. The species enlarged its trophic niche and increased the trophic level of their prey from incubation to chick-rearing, likely to provision their chicks with a more diversified and better quality diet. There was a high overlap between the Cape Verde shearwaters foraging areas with those of European shearwater species that overwinter in this area and known areas of megafauna bycatch off West Africa, but very little overlap with existing Marine Important Bird Areas. Further

  8. Identification, expression, and characterization of the highly conserved D-xylose isomerase in animals

    Institute of Scientific and Technical Information of China (English)

    Ming Ding; Yigang Teng; Qiuyu Yin; Wei Chen; Fukun Zhao

    2009-01-01

    D-xylose is a necessary sugar for animals. The xylanase from a mollusk, Ampullaria crossean, was previously reported by our laboratory. This xylanase can degrade the xylan into D-xylose. But there is still a gap in our knowledge on its metabolic pathway. The question is how does the xylose enter the pentose pathway? With the help of genomic databases and bioinformatic tools, we found that some animals, such as bacteria, have a highly conserved D-xylose isomerase (EC 5.3.1.5). The xylose isomerase from a sea squirt, Ciona intestinali, was heterogeneously expressed in Escherichia coli and purified to confirm its function. The recombinant enzyme had good thermal stability in the presence of Mg2+. At the optimum temperature and optimum pH environment, its specific activity on D-xylose was 0.331μmol/mg/min. This enzyme exists broadly in many animals, but it disappeared in the genome of Amphibia-like Xenopus laevis. Its sequence was highly conserved. The xylose isomerases from animals are very interesting proteins for the study of evolution.

  9. Quantifying Mosaic Development: Towards an Evo-Devo Postmodern Synthesis of the Evolution of Development via Differentiation Trees of Embryos.

    Science.gov (United States)

    Alicea, Bradly; Gordon, Richard

    2016-08-18

    Embryonic development proceeds through a series of differentiation events. The mosaic version of this process (binary cell divisions) can be analyzed by comparing early development of Ciona intestinalis and Caenorhabditis elegans. To do this, we reorganize lineage trees into differentiation trees using the graph theory ordering of relative cell volume. Lineage and differentiation trees provide us with means to classify each cell using binary codes. Extracting data characterizing lineage tree position, cell volume, and nucleus position for each cell during early embryogenesis, we conduct several statistical analyses, both within and between taxa. We compare both cell volume distributions and cell volume across developmental time within and between single species and assess differences between lineage tree and differentiation tree orderings. This enhances our understanding of the differentiation events in a model of pure mosaic embryogenesis and its relationship to evolutionary conservation. We also contribute several new techniques for assessing both differences between lineage trees and differentiation trees, and differences between differentiation trees of different species. The results suggest that at the level of differentiation trees, there are broad similarities between distantly related mosaic embryos that might be essential to understanding evolutionary change and phylogeny reconstruction. Differentiation trees may therefore provide a basis for an Evo-Devo Postmodern Synthesis.

  10. Combinatorial mutagenesis of the voltage-sensing domain enables the optical resolution of action potentials firing at 60 Hz by a genetically encoded fluorescent sensor of membrane potential.

    Science.gov (United States)

    Piao, Hong Hua; Rajakumar, Dhanarajan; Kang, Bok Eum; Kim, Eun Ha; Baker, Bradley J

    2015-01-07

    ArcLight is a genetically encoded fluorescent voltage sensor using the voltage-sensing domain of the voltage-sensing phosphatase from Ciona intestinalis that gives a large but slow-responding optical signal in response to changes in membrane potential (Jin et al., 2012). Fluorescent voltage sensors using the voltage-sensing domain from other species give faster yet weaker optical signals (Baker et al., 2012; Han et al., 2013). Sequence alignment of voltage-sensing phosphatases from different species revealed conserved polar and charged residues at 7 aa intervals in the S1-S3 transmembrane segments of the voltage-sensing domain, suggesting potential coil-coil interactions. The contribution of these residues to the voltage-induced optical signal was tested using a cassette mutagenesis screen by flanking each transmembrane segment with unique restriction sites to allow for the testing of individual mutations in each transmembrane segment, as well as combinations in all four transmembrane segments. Addition of a counter charge in S2 improved the kinetics of the optical response. A double mutation in the S4 domain dramatically reduced the slow component of the optical signal seen in ArcLight. Combining that double S4 mutant with the mutation in the S2 domain yielded a probe with kinetics voltage-sensing domain could potentially lead to fluorescent sensors capable of optically resolving neuronal inhibition and subthreshold synaptic activity.

  11. Voltage-dependent motion of the catalytic region of voltage-sensing phosphatase monitored by a fluorescent amino acid.

    Science.gov (United States)

    Sakata, Souhei; Jinno, Yuka; Kawanabe, Akira; Okamura, Yasushi

    2016-07-05

    The cytoplasmic region of voltage-sensing phosphatase (VSP) derives the voltage dependence of its catalytic activity from coupling to a voltage sensor homologous to that of voltage-gated ion channels. To assess the conformational changes in the cytoplasmic region upon activation of the voltage sensor, we genetically incorporated a fluorescent unnatural amino acid, 3-(6-acetylnaphthalen-2-ylamino)-2-aminopropanoic acid (Anap), into the catalytic region of Ciona intestinalis VSP (Ci-VSP). Measurements of Anap fluorescence under voltage clamp in Xenopus oocytes revealed that the catalytic region assumes distinct conformations dependent on the degree of voltage-sensor activation. FRET analysis showed that the catalytic region remains situated beneath the plasma membrane, irrespective of the voltage level. Moreover, Anap fluorescence from a membrane-facing loop in the C2 domain showed a pattern reflecting substrate turnover. These results indicate that the voltage sensor regulates Ci-VSP catalytic activity by causing conformational changes in the entire catalytic region, without changing their distance from the plasma membrane.

  12. Intra-species sequence comparisons for annotating genomes

    Energy Technology Data Exchange (ETDEWEB)

    Boffelli, Dario; Weer, Claire V.; Weng, Li; Lewis, Keith D.; Shoukry, Malak I.; Pachter, Lior; Keys, David N.; Rubin, Edward M.

    2004-07-15

    Analysis of sequence variation among members of a single species offers a potential approach to identify functional DNA elements responsible for biological features unique to that species. Due to its high rate of allelic polymorphism and ease of genetic manipulability, we chose the sea squirt, Ciona intestinalis, to explore intra-species sequence comparisons for genome annotation. A large number of C. intestinalis specimens were collected from four continents and a set of genomic intervals amplified, resequenced and analyzed to determine the mutation rates at each nucleotide in the sequence. We found that regions with low mutation rates efficiently demarcated functionally constrained sequences: these include a set of noncoding elements, which we showed in C intestinalis transgenic assays to act as tissue-specific enhancers, as well as the location of coding sequences. This illustrates that comparisons of multiple members of a species can be used for genome annotation, suggesting a path for the annotation of the sequenced genomes of organisms occupying uncharacterized phylogenetic branches of the animal kingdom and raises the possibility that the resequencing of a large number of Homo sapiens individuals might be used to annotate the human genome and identify sequences defining traits unique to our species. The sequence data from this study has been submitted to GenBank under accession nos. AY667278-AY667407.

  13. Anthropogenic transport of species across native ranges: unpredictable genetic and evolutionary consequences.

    Science.gov (United States)

    Hudson, Jamie; Viard, Frédérique; Roby, Charlotte; Rius, Marc

    2016-10-01

    Human activities are responsible for the translocation of vast amounts of organisms, altering natural patterns of dispersal and gene flow. Most research to date has focused on the consequences of anthropogenic transportation of non-indigenous species within introduced ranges, with little research focusing on native species. Here, we compared genetic patterns of the sessile marine invertebrate, Ciona intestinalis, which has highly restricted dispersal capabilities. We collected individuals in a region of the species' native range where human activities that are known to facilitate the artificial spread of species are prevalent. Using microsatellite markers, we revealed highly dissimilar outcomes. First, we found low levels of genetic differentiation among sites separated by both short and large geographical distances, indicating the presence of anthropogenic transport of genotypes, and little influence of natural geographical barriers. Second, we found significant genetic differentiation in pairwise comparisons among certain sites, suggesting that other factors besides artificial transport (e.g. natural dispersal, premodern population structure) may be shaping genetic patterns. Taken together, we found dissimilar patterns of population structure in a highly urbanized region that could not be predicted by artificial transport alone. We conclude that anthropogenic activities alter genetic composition of native ranges, with unknown consequences for species' evolutionary trajectories.

  14. Organization and evolution of a gene-rich region of the mouse genome: a 12.7-Mb region deleted in the Del(13)Svea36H mouse.

    Science.gov (United States)

    Mallon, Ann-Marie; Wilming, Laurens; Weekes, Joseph; Gilbert, James G R; Ashurst, Jennifer; Peyrefitte, Sandrine; Matthews, Lucy; Cadman, Matthew; McKeone, Richard; Sellick, Chris A; Arkell, Ruth; Botcherby, Marc R M; Strivens, Mark A; Campbell, R Duncan; Gregory, Simon; Denny, Paul; Hancock, John M; Rogers, Jane; Brown, Steve D M

    2004-10-01

    Del(13)Svea36H (Del36H) is a deletion of approximately 20% of mouse chromosome 13 showing conserved synteny with human chromosome 6p22.1-6p22.3/6p25. The human region is lost in some deletion syndromes and is the site of several disease loci. Heterozygous Del36H mice show numerous phenotypes and may model aspects of human genetic disease. We describe 12.7 Mb of finished, annotated sequence from Del36H. Del36H has a higher gene density than the draft mouse genome, reflecting high local densities of three gene families (vomeronasal receptors, serpins, and prolactins) which are greatly expanded relative to human. Transposable elements are concentrated near these gene families. We therefore suggest that their neighborhoods are gene factories, regions of frequent recombination in which gene duplication is more frequent. The gene families show different proportions of pseudogenes, likely reflecting different strengths of purifying selection and/or gene conversion. They are also associated with relatively low simple sequence concentrations, which vary across the region with a periodicity of approximately 5 Mb. Del36H contains numerous evolutionarily conserved regions (ECRs). Many lie in noncoding regions, are detectable in species as distant as Ciona intestinalis, and therefore are candidate regulatory sequences. This analysis will facilitate functional genomic analysis of Del36H and provides insights into mouse genome evolution.

  15. A specialized molecular motion opens the Hv1 voltage-gated proton channel.

    Science.gov (United States)

    Mony, Laetitia; Berger, Thomas K; Isacoff, Ehud Y

    2015-04-01

    The Hv1 proton channel is unique among voltage-gated channels for containing the pore and gate within its voltage-sensing domain. Pore opening has been proposed to include assembly of the selectivity filter between an arginine (R3) of segment S4 and an aspartate (D1) of segment S1. We determined whether gating involves motion of S1, using Ciona intestinalis Hv1. We found that channel opening is concomitant with solution access to the pore-lining face of S1, from the cytoplasm to deep inside the pore. Voltage- and patch-clamp fluorometry showed that this involves a motion of S1 relative to its surroundings. S1 motion and the S4 motion that precedes it are each influenced by residues on the other helix, thus suggesting a dynamic interaction between S1 and S4. Our findings suggest that the S1 of Hv1 has specialized to function as part of the channel's gate.

  16. Exploration of genetically encoded voltage indicators based on a chimeric voltage sensing domain

    Directory of Open Access Journals (Sweden)

    Yukiko eMishina

    2014-09-01

    Full Text Available Deciphering how the brain generates cognitive function from patterns of electrical signals is one of the ultimate challenges in neuroscience. To this end, it would be highly desirable to monitor the activities of very large numbers of neurons while an animal engages in complex behaviours. Optical imaging of electrical activity using genetically encoded voltage indicators (GEVIs has the potential to meet this challenge. Currently prevalent GEVIs are based on the voltage-sensitive fluorescent protein (VSFP prototypical design or on the voltage dependent state transitions of microbial opsins.We recently introduced a new VSFP design in which the voltage-sensing domain (VSD is sandwiched between a FRET pair of fluorescent proteins (termed VSFP-Butterflies and also demonstrated a series of chimeric VSD in which portions of the VSD of Ciona intestinalis voltage-sensitive phosphatase (Ci-VSP are substituted by homologous portions of a voltage-gated potassium channel subunit. These chimeric VSD had faster sensing kinetics than that of the native Ci-VSD. Here, we describe a new set of VSFPs that combine chimeric VSD with the Butterfly structure. We show that these chimeric VSFP-Butterflies can report membrane voltage oscillations of up to 200 Hz in cultured cells and report sensory evoked cortical population responses in living mice. This class of GEVIs may be suitable for imaging of brain rhythms in behaving mammalians.

  17. Transcript mapping of mitochondrial genome and its application%动物线粒体基因组的转录物作图与应用

    Institute of Scientific and Technical Information of China (English)

    姚杨; 黄原

    2010-01-01

    线粒体转录物作图是研究线粒体基因组表达、调控和序列主要有表达序列标签(expressed sequence tag,EST)文库测序、5'和3'cDNA末端快速扩增(rapid amplification of cDNA ends,RACE)技术和RT-PCR方法,采用这些方法已经对果蝇(Drosophila melanogaster)、按蚊(Anopheles funestus)、玻璃海鞘(Ciona intestinalis)、猪(Sus scrofa domestica)等线粒体转录组进行了分析.研究显示,脊椎动物和无脊椎动物的线粒体基因组分别产生3个和5个多顺反子的初级转录物,并通过tRNA间断模型(tRNA punctuation model)加工.线粒体转录物的分析结果为正确注释线粒体基因组序列提供了重要信息.

  18. The amphioxus genome provides unique insight into the evolution of immunity.

    Science.gov (United States)

    Dishaw, Larry J; Haire, Robert N; Litman, Gary W

    2012-03-01

    Immune systems evolve as essential strategies to maintain homeostasis with the environment, prevent microbial assault and recycle damaged host tissues. The immune system is composed of two components, innate and adaptive immunity. The former is common to all animals while the latter consists of a vertebrate-specific system that relies on somatically derived lymphocytes and is associated with near limitless genetic diversity as well as long-term memory. Deuterostome invertebrates provide a view of immune repertoires in phyla that immediately predate the origins of vertebrates. Genomic studies in amphioxus, a cephalochordate, have revealed homologs of genes encoding most innate immune receptors found in vertebrates; however, many of the gene families have undergone dramatic expansions, greatly increasing the innate immune repertoire. In addition, domain-swapping accounts for the innovation of new predicted pathways of receptor function. In both amphioxus and Ciona, a urochordate, the VCBPs (variable region containing chitin-binding proteins), which consist of immunoglobulin V (variable) and chitin binding domains, mediate recognition through the V domains. The V domains of VCBPs in amphioxus exhibit high levels of allelic complexity that presumably relate to functional specificity. Various features of the amphioxus immune repertoire reflect novel selective pressures, which likely have resulted in innovative strategies. Functional genomic studies underscore the value of amphioxus as a model for studying innate immunity and may help reveal how unique relationships between innate immune receptors and both pathogens and symbionts factored in the evolution of adaptive immune systems.

  19. Branchial Cilia and Sperm Flagella Recruit Distinct Axonemal Components

    Science.gov (United States)

    Konno, Alu; Shiba, Kogiku; Cai, Chunhua; Inaba, Kazuo

    2015-01-01

    Eukaryotic cilia and flagella have highly conserved 9 + 2 structures. They are functionally diverged to play cell-type-specific roles even in a multicellular organism. Although their structural components are therefore believed to be common, few studies have investigated the molecular diversity of the protein components of the cilia and flagella in a single organism. Here we carried out a proteomic analysis and compared protein components between branchial cilia and sperm flagella in a marine invertebrate chordate, Ciona intestinalis. Distinct feature of protein recruitment in branchial cilia and sperm flagella has been clarified; (1) Isoforms of α- and β-tubulins as well as those of actins are distinctly used in branchial cilia or sperm flagella. (2) Structural components, such as dynein docking complex, tektins and an outer dense fiber protein, are used differently by the cilia and flagella. (3) Sperm flagella are specialized for the cAMP- and Ca2+-dependent regulation of outer arm dynein and for energy metabolism by glycolytic enzymes. Our present study clearly demonstrates that flagellar or ciliary proteins are properly recruited according to their function and stability, despite their apparent structural resemblance and conservation. PMID:25962172

  20. Branchial cilia and sperm flagella recruit distinct axonemal components.

    Directory of Open Access Journals (Sweden)

    Alu Konno

    Full Text Available Eukaryotic cilia and flagella have highly conserved 9 + 2 structures. They are functionally diverged to play cell-type-specific roles even in a multicellular organism. Although their structural components are therefore believed to be common, few studies have investigated the molecular diversity of the protein components of the cilia and flagella in a single organism. Here we carried out a proteomic analysis and compared protein components between branchial cilia and sperm flagella in a marine invertebrate chordate, Ciona intestinalis. Distinct feature of protein recruitment in branchial cilia and sperm flagella has been clarified; (1 Isoforms of α- and β-tubulins as well as those of actins are distinctly used in branchial cilia or sperm flagella. (2 Structural components, such as dynein docking complex, tektins and an outer dense fiber protein, are used differently by the cilia and flagella. (3 Sperm flagella are specialized for the cAMP- and Ca2+-dependent regulation of outer arm dynein and for energy metabolism by glycolytic enzymes. Our present study clearly demonstrates that flagellar or ciliary proteins are properly recruited according to their function and stability, despite their apparent structural resemblance and conservation.

  1. Transfer of Kv3.1 voltage sensor features to the isolated Ci-VSP voltage-sensing domain.

    Science.gov (United States)

    Mishina, Yukiko; Mutoh, Hiroki; Knöpfel, Thomas

    2012-08-22

    Membrane proteins that respond to changes in transmembrane voltage are critical in regulating the function of living cells. The voltage-sensing domains (VSDs) of voltage-gated ion channels are extensively studied to elucidate voltage-sensing mechanisms, and yet many aspects of their structure-function relationship remain elusive. Here, we transplanted homologous amino acid motifs from the tetrameric voltage-activated potassium channel Kv3.1 to the monomeric VSD of Ciona intestinalis voltage-sensitive phosphatase (Ci-VSP) to explore which portions of Kv3.1 subunits depend on the tetrameric structure of Kv channels and which properties of Kv3.1 can be transferred to the monomeric Ci-VSP scaffold. By attaching fluorescent proteins to these chimeric VSDs, we obtained an optical readout to establish membrane trafficking and kinetics of voltage-dependent structural rearrangements. We found that motifs extending from 10 to roughly 100 amino acids can be readily transplanted from Kv3.1 into Ci-VSP to form engineered VSDs that efficiently incorporate into the plasma membrane and sense voltage. Some of the functional features of these engineered VSDs are reminiscent of Kv3.1 channels, indicating that these properties do not require interactions between Kv subunits or between the voltage sensing and the pore domains of Kv channels.

  2. Functional evolution of ADAMTS genes: Evidence from analyses of phylogeny and gene organization

    Directory of Open Access Journals (Sweden)

    Van Meir Erwin G

    2005-02-01

    Full Text Available Abstract Background The ADAMTS (A Disintegrin-like and Metalloprotease with Thrombospondin motifs proteins are a family of metalloproteases with sequence similarity to the ADAM proteases, that contain the thrombospondin type 1 sequence repeat motifs (TSRs common to extracellular matrix proteins. ADAMTS proteins have recently gained attention with the discovery of their role in a variety of diseases, including tissue and blood disorders, cancer, osteoarthritis, Alzheimer's and the genetic syndromes Weill-Marchesani syndrome (ADAMTS10, thrombotic thrombocytopenic purpura (ADAMTS13, and Ehlers-Danlos syndrome type VIIC (ADAMTS2 in humans and belted white-spotting mutation in mice (ADAMTS20. Results Phylogenetic analysis and comparison of the exon/intron organization of vertebrate (Homo, Mus, Fugu, chordate (Ciona and invertebrate (Drosophila and Caenorhabditis ADAMTS homologs has elucidated the evolutionary relationships of this important gene family, which comprises 19 members in humans. Conclusions The evolutionary history of ADAMTS genes in vertebrate genomes has been marked by rampant gene duplication, including a retrotransposition that gave rise to a distinct ADAMTS subfamily (ADAMTS1, -4, -5, -8, -15 that may have distinct aggrecanase and angiogenesis functions.

  3. Phenotypic rescue of a Drosophila model of mitochondrial ANT1 disease

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    Suvi Vartiainen

    2014-06-01

    Full Text Available A point mutation in the Drosophila gene that codes for the major adult isoform of adenine nuclear translocase (ANT represents a model for human diseases that are associated with ANT insufficiency [stress-sensitive B1 (sesB1]. We characterized the organismal, bioenergetic and molecular phenotype of sesB1 flies then tested strategies to compensate the mutant phenotype. In addition to developmental delay and mechanical-stress-induced seizures, sesB1 flies have an impaired response to sound, defective male courtship, female sterility and curtailed lifespan. These phenotypes, excluding the latter two, are shared with the mitoribosomal protein S12 mutant, tko25t. Mitochondria from sesB1 adults showed a decreased respiratory control ratio and downregulation of cytochrome oxidase. sesB1 adults exhibited ATP depletion, lactate accumulation and changes in gene expression that were consistent with a metabolic shift towards glycolysis, characterized by activation of lactate dehydrogenase and anaplerotic pathways. Females also showed downregulation of many genes that are required for oogenesis, and their eggs, although fertilized, failed to develop to the larval stages. The sesB1 phenotypes of developmental delay and mechanical-stress-induced seizures were alleviated by an altered mitochondrial DNA background. Female sterility was substantially rescued by somatic expression of alternative oxidase (AOX from the sea squirt Ciona intestinalis, whereas AOX did not alleviate developmental delay. Our findings illustrate the potential of different therapeutic strategies for ANT-linked diseases, based on alleviating metabolic stress.

  4. New developments in the second heart field.

    Science.gov (United States)

    Zaffran, Stéphane; Kelly, Robert G

    2012-07-01

    During cardiac looping the heart tube elongates by addition of progenitor cells from adjacent pharyngeal mesoderm to the arterial and venous poles. This cell population, termed the second heart field, was first identified ten years ago and many studies in the intervening decade have refined our understanding of how heart tube elongation takes place and identified signaling pathways that regulate proliferation and differentiation during progressive contribution of second heart field cells to the embryonic heart. It has also become apparent that defective second heart field development results in common congenital heart anomalies affecting both the conotruncal region and venous pole of the heart, including atrial and atrioventricular septal defects. In this review we focus on a series of recent papers that have identified new regulators of second heart field development, in particular the retinoic acid signaling pathway and HOX, SIX and EYA transcription factors. We also discuss new findings concerning the regulation of fibroblast growth factor signaling during second heart field deployment and studies that have implicated FGF10 and FGF3 in outflow tract development in addition to FGF8. Second heart field derived parts of the heart share common progenitor cells in pharyngeal mesoderm with craniofacial skeletal muscles and recent findings from xenopus, zebrafish and the protochordate Ciona intestinalis provide insights into the evolution of the second heart field during vertebrate radiation.

  5. Expression of the alternative oxidase mitigates beta-amyloid production and toxicity in model systems.

    Science.gov (United States)

    El-Khoury, Riyad; Kaulio, Eveliina; Lassila, Katariina A; Crowther, Damian C; Jacobs, Howard T; Rustin, Pierre

    2016-07-01

    Mitochondrial dysfunction has been widely associated with the pathology of Alzheimer's disease, but there is no consensus on whether it is a cause or consequence of disease, nor on the precise mechanism(s). We addressed these issues by testing the effects of expressing the alternative oxidase AOX from Ciona intestinalis, in different models of AD pathology. AOX can restore respiratory electron flow when the cytochrome segment of the mitochondrial respiratory chain is inhibited, supporting ATP synthesis, maintaining cellular redox homeostasis and mitigating excess superoxide production at respiratory complexes I and III. In human HEK293-derived cells, AOX expression decreased the production of beta-amyloid peptide resulting from antimycin inhibition of respiratory complex III. Because hydrogen peroxide was neither a direct product nor substrate of AOX, the ability of AOX to mimic antioxidants in this assay must be indirect. In addition, AOX expression was able to partially alleviate the short lifespan of Drosophila models neuronally expressing human beta-amyloid peptides, whilst abrogating the induction of markers of oxidative stress. Our findings support the idea of respiratory chain dysfunction and excess ROS production as both an early step and as a pathologically meaningful target in Alzheimer's disease pathogenesis, supporting the concept of a mitochondrial vicious cycle underlying the disease.

  6. The evolution and comparative neurobiology of endocannabinoid signalling.

    Science.gov (United States)

    Elphick, Maurice R

    2012-12-05

    CB(1)- and CB(2)-type cannabinoid receptors mediate effects of the endocannabinoids 2-arachidonoylglycerol (2-AG) and anandamide in mammals. In canonical endocannabinoid-mediated synaptic plasticity, 2-AG is generated postsynaptically by diacylglycerol lipase alpha and acts via presynaptic CB(1)-type cannabinoid receptors to inhibit neurotransmitter release. Electrophysiological studies on lampreys indicate that this retrograde signalling mechanism occurs throughout the vertebrates, whereas system-level studies point to conserved roles for endocannabinoid signalling in neural mechanisms of learning and control of locomotor activity and feeding. CB(1)/CB(2)-type receptors originated in a common ancestor of extant chordates, and in the sea squirt Ciona intestinalis a CB(1)/CB(2)-type receptor is targeted to axons, indicative of an ancient role for cannabinoid receptors as axonal regulators of neuronal signalling. Although CB(1)/CB(2)-type receptors are unique to chordates, enzymes involved in biosynthesis/inactivation of endocannabinoids occur throughout the animal kingdom. Accordingly, non-CB(1)/CB(2)-mediated mechanisms of endocannabinoid signalling have been postulated. For example, there is evidence that 2-AG mediates retrograde signalling at synapses in the nervous system of the leech Hirudo medicinalis by activating presynaptic transient receptor potential vanilloid-type ion channels. Thus, postsynaptic synthesis of 2-AG or anandamide may be a phylogenetically widespread phenomenon, and a variety of proteins may have evolved as presynaptic (or postsynaptic) receptors for endocannabinoids.

  7. A conserved non-reproductive GnRH system in chordates.

    Directory of Open Access Journals (Sweden)

    Takehiro G Kusakabe

    Full Text Available Gonadotropin-releasing hormone (GnRH is a neuroendocrine peptide that plays a central role in the vertebrate hypothalamo-pituitary axis. The roles of GnRH in the control of vertebrate reproductive functions have been established, while its non-reproductive function has been suggested but less well understood. Here we show that the tunicate Ciona intestinalis has in its non-reproductive larval stage a prominent GnRH system spanning the entire length of the nervous system. Tunicate GnRH receptors are phylogenetically closest to vertebrate GnRH receptors, yet functional analysis of the receptors revealed that these simple chordates have evolved a unique GnRH system with multiple ligands and receptor heterodimerization enabling complex regulation. One of the gnrh genes is conspicuously expressed in the motor ganglion and nerve cord, which are homologous structures to the hindbrain and spinal cord of vertebrates. Correspondingly, GnRH receptor genes were found to be expressed in the tail muscle and notochord of embryos, both of which are phylotypic axial structures along the nerve cord. Our findings suggest a novel non-reproductive role of GnRH in tunicates. Furthermore, we present evidence that GnRH-producing cells are present in the hindbrain and spinal cord of the medaka, Oryzias latipes, thereby suggesting the deep evolutionary origin of a non-reproductive GnRH system in chordates.

  8. Syntax compensates for poor binding sites to encode tissue specificity of developmental enhancers.

    Science.gov (United States)

    Farley, Emma K; Olson, Katrina M; Zhang, Wei; Rokhsar, Daniel S; Levine, Michael S

    2016-06-07

    Transcriptional enhancers are short segments of DNA that switch genes on and off in response to a variety of intrinsic and extrinsic signals. Despite the discovery of the first enhancer more than 30 y ago, the relationship between primary DNA sequence and enhancer activity remains obscure. In particular, the importance of "syntax" (the order, orientation, and spacing of binding sites) is unclear. A high-throughput screen identified synthetic notochord enhancers that are activated by the combination of ZicL and ETS transcription factors in Ciona embryos. Manipulation of these enhancers elucidated a "regulatory code" of sequence and syntax features for notochord-specific expression. This code enabled in silico discovery of bona fide notochord enhancers, including those containing low-affinity binding sites that would be excluded by standard motif identification methods. One of the newly identified enhancers maps upstream of the known enhancer that regulates Brachyury (Ci-Bra), a key determinant of notochord specification. This newly identified Ci-Bra shadow enhancer contains binding sites with very low affinity, but optimal syntax, and therefore mediates surprisingly strong expression in the notochord. Weak binding sites are compensated by optimal syntax, whereas enhancers containing high-affinity binding affinities possess suboptimal syntax. We suggest this balance has obscured the importance of regulatory syntax, as noncanonical binding motifs are typically disregarded by enhancer detection methods. As a result, enhancers with low binding affinities but optimal syntax may be a vastly underappreciated feature of the regulatory genome.

  9. Assembly and positioning of actomyosin rings by contractility and planar cell polarity.

    Science.gov (United States)

    Sehring, Ivonne M; Recho, Pierre; Denker, Elsa; Kourakis, Matthew; Mathiesen, Birthe; Hannezo, Edouard; Dong, Bo; Jiang, Di

    2015-10-21

    The actomyosin cytoskeleton is a primary force-generating mechanism in morphogenesis, thus a robust spatial control of cytoskeletal positioning is essential. In this report, we demonstrate that actomyosin contractility and planar cell polarity (PCP) interact in post-mitotic Ciona notochord cells to self-assemble and reposition actomyosin rings, which play an essential role for cell elongation. Intriguingly, rings always form at the cells' anterior edge before migrating towards the center as contractility increases, reflecting a novel dynamical property of the cortex. Our drug and genetic manipulations uncover a tug-of-war between contractility, which localizes cortical flows toward the equator and PCP, which tries to reposition them. We develop a simple model of the physical forces underlying this tug-of-war, which quantitatively reproduces our results. We thus propose a quantitative framework for dissecting the relative contribution of contractility and PCP to the self-assembly and repositioning of cytoskeletal structures, which should be applicable to other morphogenetic events.

  10. Institutciones estatales y orden político. Diseño, prácticas y representaciones de la Justicia Federal en la ‘Confederación’ (1854-1861.

    Directory of Open Access Journals (Sweden)

    Ana Laura Lanteri

    2011-01-01

    Full Text Available El artículo estudia algunos avatares de la organización y el funcionamiento de la justicia federal en la “Confederación” (1854-1861. El análisis contempla problemas que han sido soslayados por los estudios existentes. El enfoque escogido vincula la problemática con las redefi niciones del rol y de los vín- culos político-institucionales de los poderes provinciales y el nacional y rela- ciona al poder judicial con los otros dos poderes estatales. En primer lugar se analiza la ley que, al disponer los requisitos de habilitación de los “abogados nacionales”, permitió la conformación de la justicia federal. Luego, se exami- na su dinámica desde el accionar de las provincias y de la Cámara Superior de Justicia (que suplió a la Corte Suprema de Justicia. Finalmente, se reali- zan algunas consideraciones fi nales en las que se proyecta la experiencia ha- cia el período abierto en 1862.

  11. The evolution and comparative neurobiology of endocannabinoid signalling

    Science.gov (United States)

    Elphick, Maurice R.

    2012-01-01

    CB1- and CB2-type cannabinoid receptors mediate effects of the endocannabinoids 2-arachidonoylglycerol (2-AG) and anandamide in mammals. In canonical endocannabinoid-mediated synaptic plasticity, 2-AG is generated postsynaptically by diacylglycerol lipase alpha and acts via presynaptic CB1-type cannabinoid receptors to inhibit neurotransmitter release. Electrophysiological studies on lampreys indicate that this retrograde signalling mechanism occurs throughout the vertebrates, whereas system-level studies point to conserved roles for endocannabinoid signalling in neural mechanisms of learning and control of locomotor activity and feeding. CB1/CB2-type receptors originated in a common ancestor of extant chordates, and in the sea squirt Ciona intestinalis a CB1/CB2-type receptor is targeted to axons, indicative of an ancient role for cannabinoid receptors as axonal regulators of neuronal signalling. Although CB1/CB2-type receptors are unique to chordates, enzymes involved in biosynthesis/inactivation of endocannabinoids occur throughout the animal kingdom. Accordingly, non-CB1/CB2-mediated mechanisms of endocannabinoid signalling have been postulated. For example, there is evidence that 2-AG mediates retrograde signalling at synapses in the nervous system of the leech Hirudo medicinalis by activating presynaptic transient receptor potential vanilloid-type ion channels. Thus, postsynaptic synthesis of 2-AG or anandamide may be a phylogenetically widespread phenomenon, and a variety of proteins may have evolved as presynaptic (or postsynaptic) receptors for endocannabinoids. PMID:23108540

  12. Sexual and asexual reproduction in Didemnum rodriguesi (Ascidiacea, Didemnidae Reprodução sexuada e assexuada em Didemnum rodriguesi (Ascidiacea, Didemnidae

    Directory of Open Access Journals (Sweden)

    Nicole F. Ritzmann

    2009-03-01

    Full Text Available Sexual and asexual reproduction and associated population dynamics were investigated in the colonial ascidian Didemnum rodriguesi Rocha & Monniot, 1993 (Didemnidae in southern Brazil. Investment in sexual (production of new individuals and asexual (colony growth reproduction was compared between seasons. Permanently marked quadrats were repeatedly photographed to measure changes in colonies. Eggs and larvae were counted monthly in collected colonies. This species alternates seasonally between sexual (summer and asexual (winter reproduction. In summer, colonies were smaller, brooded eggs and larvae and recruitment rates were greater, while in winter, colony size was larger and eggs and larvae were absent. There is a relationship between fecundity and colony area. Fragmentation and fusion of colonies were similar in summer and winter, as well as mortality. In conclusion, D. rodriguesi has a lifecycle usual for high latitude ascidians with a limited time length for sexual reproduction and alternate investment in sexual and asexual reproduction along the year.Reprodução sexuada e assexuada, mortalidade e a dinâmica de fusões e fissões de colônias de Didemnum rodriguesi Rocha & Monniot, 1993 foram investigados e comparados no sul do Brasil, no inverno e verão. Tais eventos foram analisados por fotografias de áreas permanentemente demarcadas e coletas mensais de colônias. Os resultados indicam que esta espécie alterna sazonalmente a reprodução sexuada (verão e assexuada (inverno. Durante o verão as colônias são mais abundantes e menores, com ovos e larvas incubados e taxas de recrutamento maiores. No inverno há um menor número de colônias, porém de maior tamanho e inférteis. Existe uma relação entre fecundidade e tamanho da colônia. Não foram encontradas diferenças estatísticas no número de eventos de fragmentação e fusão entre o verão e inverno, bem como para mortalidade. Conclui-se que esta espécie tem um ciclo de

  13. Specific sulfation and glycosylation—a structural combination for the anticoagulation of marine carbohydrates

    Science.gov (United States)

    Pomin, Vitor H.; Mourão, Paulo A. S.

    2014-01-01

    Based on considered achievements of the last 25 years, specific combinations of sulfation patterns and glycosylation types have been proved to be key structural players for the anticoagulant activity of certain marine glycans. These conclusions were obtained from comparative and systematic analyses on the structure-anticoagulation relationships of chemically well-defined sulfated polysaccharides of marine invertebrates and red algae. These sulfated polysaccharides are known as sulfated fucans (SFs), sulfated galactans (SGs) and glycosaminoglycans (GAGs). The structural combinations necessary for the anticoagulant activities are the 2-sulfation in α-L-SGs, the 2,4-di-sulfation in α-L-fucopyranosyl units found as composing units of certain sea-urchin and sea-cucumber linear SFs, or as branching units of the fucosylated chondroitin sulfate, a unique GAG from sea-cucumbers. Another unique GAG type from marine organisms is the dermatan sulfate isolated from ascidians. The high levels of 4-sulfation at the galactosamine units combined with certain levels of 2-sulfation at the iduronic acid units is the anticoagulant structural requirements of these GAGs. When the backbones of red algal SGs are homogeneous, the anticoagulation is proportionally dependent of their sulfation content. Finally, 4-sulfation was observed to be the structural motif required to enhance the inhibition of thrombin via heparin cofactor-II by invertebrate SFs. PMID:24639954

  14. Plant-like mating in an animal: sexual compatibility and allocation trade-offs in a simultaneous hermaphrodite with remote transfer of sperm.

    Science.gov (United States)

    Pemberton, A J; Sommerfeldt, A D; Wood, C A; Flint, H C; Noble, L R; Clarke, K R; Bishop, J D D

    2004-05-01

    The importance of sexual compatibility between mates has only recently been realized in zoological research into sexual selection, yet its study has been central to botanical research for many decades. The reproductive characteristics of remote mating, an absence of precopulatory mate screening, internal fertilization and embryonic brooding are shared between passively pollinated plants and a phylogenetically diverse group of sessile aquatic invertebrates. Here, we further characterize the sexual compatibility system of one such invertebrate, the colonial ascidian Diplosoma listerianum. All 66 reciprocal pairings of 12 genetic individuals were carried out. Fecundities of crosses varied widely and suggested a continuous scale of sexual compatibility. Of the 11 animals from the same population c. 40% of crosses were completely incompatible with a further c. 20% having obvious partial compatibility (reduced fecundity). We are unaware of other studies documenting such high levels of sexual incompatibility in unrelated individuals. RAPD fingerprinting was used to estimate relatedness among the 12 individuals after a known pedigree was successfully reconstructed to validate the technique. In contrast to previous results, no correlation between genetic similarity and sexual compatibility was detected. The blocking of many genotypes of sperm is expected to severely modify realized paternity away from 'fair raffle' expectations and probably reduce levels of intra-brood genetic diversity in this obligatorily promiscuous mating system. One adaptive benefit may be to reduce the bombardment of the female reproductive system by outcrossed sperm with conflicting evolutionary interests, so as to maintain female control of somatic : gametic investment.

  15. Shells and heart: are human laterality and chirality of snails controlled by the same maternal genes?

    Science.gov (United States)

    Oliverio, Marco; Digilio, Maria Cristina; Versacci, Paolo; Dallapiccola, Bruno; Marino, Bruno

    2010-10-01

    The body of most animals display left-right asymmetry of internal organs. Alteration of such asymmetry results in severe congenital defects particularly affecting the cardiovascular system. The earliest known genes involved in asymmetry, the Nodal signalling cascade, are expressed asymmetrically during embryonic development. Nodal was discovered in the mouse, but orthologs (also involved in left-right specification) were reported in ascidians, sea-urchins, and snails. Mutations in Nodal-pathway genes cause alteration of several aspects of chirality, but not entirely mirror phenotypes of the body. Other factors upstream of nodal must be involved in the generation of left-right asymmetry. In snails, breeding experiments have demonstrated that chirality is controlled by a nuclear gene with maternal effect. Given the available evidence, we propose that an evolutionarily conserved genetic basis of chirality (the same that controls left-right asymmetry in snails) is a major synapomorphy of the Bilateria. This hypothesis fits with the observation that: (a) the proportion of patients with heterotaxy and a detected mutation in a gene of the Nodal cascade is actually low, and (b) horizontal recurrence of laterality defects is remarkably more frequent than vertical recurrence, and includes a notable number of affected sibs and/or repeated abortions from unaffected mothers. Identification of the maternal gene(s) involved will allow for the identification of homozygous females at risk of having affected children and spontaneous abortions, and would provide a general medical framework for understanding the genetics of most alterations of chirality.

  16. An epizootic of Florida manatees associated with a dinoflagellate bloom

    Science.gov (United States)

    O'Shea, T.J.; Rathbun, G.B.; Bonde, R.K.; Buergelt, C.D.; Odell, D.K.

    1991-01-01

    Over a 10-wk period in early 1982, 39 Florida manatees (Trichechus manatus latirostris) were found dead in the lower Caloosahatchee River and nearby waters of southwestern Florida. Two were killed by boats. The remainder showed no evidence of trauma. Lesions indicative of infectious agents were not identified, and bacteriological and contaminant residue findings were unremarkable. Nonspecific lesions of congestion and hemorrhage were identified in brain tissue. Numerous reports were also received of manatee morbidity. Some distressed manatees showed no biochemical lesions in clinical analyses of blood samples and recovered quickly. Timing of manatee illnesses coincided with fish and double-crested cormorant (Phalacrocorax auritus) mortality and morbidity. A widespread bloom of the dinoflagellate red tide organism (Gymnodinium breve) also coincided with these incidents. G. breve produces potent neurotoxins (brevetoxins). Circumstantial evidence links these events, and possible routes of exposure may include ingestion of filter-feeding ascidians. Ecological conditions that magnified the extent of the epizootic included an early dispersal of manatees into the area from a nearby winter aggregation site and unusually high salinities that facilitated the inshore spread of the red tide bloom. Management responses to future episodes of red tide in manatee areas are suggested.

  17. Investigation of indolglyoxamide and indolacetamide analogues of polyamines as antimalarial and antitrypanosomal agents.

    Science.gov (United States)

    Wang, Jiayi; Kaiser, Marcel; Copp, Brent R

    2014-05-28

    Pure compound screening has previously identified the indolglyoxy lamidospermidine ascidian metabolites didemnidine A and B (2 and 3) to be weak growth inhibitors of Trypanosoma brucei rhodesiense (IC50 59 and 44 μM, respectively) and Plasmodium falciparum (K1 dual drug resistant strain) (IC50 41 and 15 μM, respectively), but lacking in selectivity (L6 rat myoblast, IC50 24 μM and 25 μM, respectively). To expand the structure-activity relationship of this compound class towards both parasites, we have prepared and biologically tested a library of analogues that includes indoleglyoxyl and indoleacetic "capping acids", and polyamines including spermine (PA3-4-3) and extended analogues PA3-8-3 and PA3-12-3. 7-Methoxy substituted indoleglyoxylamides were typically found to exhibit the most potent antimalarial activity (IC50 10-92 nM) but with varying degrees of selectivity versus the L6 rat myoblast cell line. A 6-methoxyindolglyoxylamide analogue was the most potent growth inhibitor of T. brucei (IC50 0.18 μM) identified in the study: it, however, also exhibited poor selectivity (L6 IC50 6.0 μM). There was no apparent correlation between antimalarial and anti-T. brucei activity in the series. In vivo evaluation of one analogue against Plasmodium berghei was undertaken, demonstrating a modest 20.9% reduction in parasitaemia.

  18. Biochemical and toxicological evaluation of nano-heparins in cell functional properties, proteasome activation and expression of key matrix molecules.

    Science.gov (United States)

    Piperigkou, Zoi; Karamanou, Konstantina; Afratis, Nikolaos A; Bouris, Panagiotis; Gialeli, Chrysostomi; Belmiro, Celso L R; Pavão, Mauro S G; Vynios, Dimitrios H; Tsatsakis, Aristidis M

    2016-01-05

    The glycosaminoglycan heparin and its derivatives act strongly on blood coagulation, controlling the activity of serine protease inhibitors in plasma. Nonetheless, there is accumulating evidence highlighting different anticancer activities of these molecules in numerous types of cancer. Nano-heparins may have great biological significance since they can inhibit cell proliferation and invasion as well as inhibiting proteasome activation. Moreover, they can cause alterations in the expression of major modulators of the tumor microenvironment, regulating cancer cell behavior. In the present study, we evaluated the effects of two nano-heparin formulations: one isolated from porcine intestine and the other from the sea squirt Styela plicata, on a breast cancer cell model. We determined whether these nano-heparins are able to affect cell proliferation, apoptosis and invasion, as well as proteasome activity and the expression of extracellular matrix molecules. Specifically, we observed that nano-Styela compared to nano-Mammalian analogue has higher inhibitory role on cell proliferation, invasion and proteasome activity. Moreover, nano-Styela regulates cell apoptosis, expression of inflammatory molecules, such as IL-6 and IL-8 and reduces the expression levels of extracellular matrix macromolecules, such as the proteolytic enzymes MT1-MMP, uPA and the cell surface proteoglycans syndecan-1 and -2, but not on syndecan-4. The observations reported in the present article indicate that nano-heparins and especially ascidian heparin are effective agents for heparin-induced effects in critical cancer cell functions, providing an important possibility in pharmacological targeting.

  19. Biosynthetic origin of natural products isolated from marine microorganism-invertebrate assemblages.

    Science.gov (United States)

    Simmons, T Luke; Coates, R Cameron; Clark, Benjamin R; Engene, Niclas; Gonzalez, David; Esquenazi, Eduardo; Dorrestein, Pieter C; Gerwick, William H

    2008-03-25

    In all probability, natural selection began as ancient marine microorganisms were required to compete for limited resources. These pressures resulted in the evolution of diverse genetically encoded small molecules with a variety of ecological and metabolic roles. Remarkably, many of these same biologically active molecules have potential utility in modern medicine and biomedical research. The most promising of these natural products often derive from organisms richly populated by associated microorganisms (e.g., marine sponges and ascidians), and often there is great uncertainty about which organism in these assemblages is making these intriguing metabolites. To use the molecular machinery responsible for the biosynthesis of potential drug-lead natural products, new tools must be applied to delineate their genetic and enzymatic origins. The aim of this perspective is to highlight both traditional and emerging techniques for the localization of metabolic pathways within complex marine environments. Examples are given from the literature as well as recent proof-of-concept experiments from the authors' laboratories.

  20. Observations on the morphology of embryonic and larval development in Styela canopus Savigny

    Institute of Scientific and Technical Information of China (English)

    Huang Ying; Ke Caihuan; Feng Danqing; Zhou Shiqiang; Li Fuxue

    2003-01-01

    The morphological characters on different developmental phases of embryo and larva and the schedule of the whole early developmental process in Styela canopus were observed and described.The types of reproduction and early development as well as the morphology of egg and larva in different ascidian species were compared. Styela canopus is oviparous. Its egg, 230.4~336.0 μm in diameter, is equipped with extraembryonic cell layers measured 43.2~ 63.0 μm thick. The early development of Styela canopus is typical urodele development, including fertilization, cleavage, gastrulation, tadpole in membrane, tadpole, initiating metamorphosis and juvenile. The tadpole of Styela canopus, with a length of 0.6~0.9 mm, consists of trunk and tail. There are obvious notochord, ocellus and adhesive papillae in the tadpole. Under the water temperature of (25 ± 0.5)℃ and the salinity of 27.0, the larva was hatched after 9.5~ 11.0 h since the fertilization.

  1. Halistanol sulfate A and rodriguesines A and B are antimicrobial and antibiofilm agents against the cariogenic bacterium Streptococcus mutans

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    Bruna de A. Lima

    2014-12-01

    Full Text Available In the present investigation we report the antibacterial activity of halistanol sulfate A isolated from the sponge Petromica ciocalyptoides, as well as of rodriguesines A and B isolated from the ascidian Didemnum sp., against the caries etiologic agent Streptococcus mutans. The transcription levels of S. mutans virulence genes gtfB, gtfC and gbpB, as well as of housekeeping genes groEL and 16S, were evaluated by sqRT-PCR analysis of S. mutans planktonic cells. There were no alterations in the expression levels of groEL and 16S after antimicrobial treatment with halistanol sulfate A and with rodriguesines A and B, but the expression of the genes gtfB, gtfC and gbpB was down-regulated. Halistanol sulfate A displayed the most potent antimicrobial effect against S. mutans, with inhibition of biofilm formation and reduction of biofilm-associated gene expression in planktonic cells. Halistanol sulfate A also inhibited the initial oral bacteria colonizers, such as Streptococcus sanguinis, but at much higher concentrations. The results obtained indicate that halistanol sulfate A may be considered a potential scaffold for drug development in Streptococcus mutans antibiofilm therapy, the main etiologic agent of human dental caries.

  2. Global diversity of Ascidiacea.

    Science.gov (United States)

    Shenkar, Noa; Swalla, Billie J

    2011-01-01

    The class Ascidiacea presents fundamental opportunities for research in the fields of development, evolution, ecology, natural products and more. This review provides a comprehensive overview of the current knowledge regarding the global biodiversity of the class Ascidiacea, focusing in their taxonomy, main regions of biodiversity, and distribution patterns. Based on analysis of the literature and the species registered in the online World Register of Marine Species, we assembled a list of 2815 described species. The highest number of species and families is found in the order Aplousobranchia. Didemnidae and Styelidae families have the highest number of species with more than 500 within each group. Sixty percent of described species are colonial. Species richness is highest in tropical regions, where colonial species predominate. In higher latitudes solitary species gradually contribute more to the total species richness. We emphasize the strong association between species richness and sampling efforts, and discuss the risks of invasive species. Our inventory is certainly incomplete as the ascidian fauna in many areas around the world is relatively poorly known, and many new species continue to be discovered and described each year.

  3. Global diversity of Ascidiacea.

    Directory of Open Access Journals (Sweden)

    Noa Shenkar

    Full Text Available The class Ascidiacea presents fundamental opportunities for research in the fields of development, evolution, ecology, natural products and more. This review provides a comprehensive overview of the current knowledge regarding the global biodiversity of the class Ascidiacea, focusing in their taxonomy, main regions of biodiversity, and distribution patterns. Based on analysis of the literature and the species registered in the online World Register of Marine Species, we assembled a list of 2815 described species. The highest number of species and families is found in the order Aplousobranchia. Didemnidae and Styelidae families have the highest number of species with more than 500 within each group. Sixty percent of described species are colonial. Species richness is highest in tropical regions, where colonial species predominate. In higher latitudes solitary species gradually contribute more to the total species richness. We emphasize the strong association between species richness and sampling efforts, and discuss the risks of invasive species. Our inventory is certainly incomplete as the ascidian fauna in many areas around the world is relatively poorly known, and many new species continue to be discovered and described each year.

  4. In Vitro Acylation of Okadaic Acid in the Presence of Various Bivalves’ Extracts

    Directory of Open Access Journals (Sweden)

    Mari Yotsu-Yamashita

    2013-01-01

    Full Text Available The dinoflagellate Dinophysis spp. is responsible for diarrhetic shellfish poisoning (DSP. In the bivalves exposed to the toxic bloom of the dinoflagellate, dinophysistoxin 3 (DTX3, the 7-OH acylated form of either okadaic acid (OA or DTX1, is produced. We demonstrated in vitro acylation of OA with palmitoyl CoA in the presence of protein extract from the digestive gland, but not other tissues of the bivalve Mizuhopecten yessoensis. The yield of 7-O-palmitoyl OA reached its maximum within 2 h, was the highest at 37 °C followed by 28 °C, 16 °C and 4 °C and was the highest at pH 8 in comparison with the yields at pH 6 and pH 4. The transformation also proceeded when the protein extract was prepared from the bivalves Corbicula japonica and Crassostrea gigas. The OA binding protein OABP2 identified in the sponge Halichondria okadai was not detected in the bivalve M. yessoensis, the bivalve Mytilus galloprovincialis and the ascidian Halocynthia roretzi, though they are known to accumulate diarrhetic shellfish poisoning toxins. Since DTX3 does not bind to protein phosphatases 1 and 2A, the physiological target for OA and DTXs in mammalian cells, the acylation of DSP toxins would be related to a detoxification mechanism for the bivalve species.

  5. Immunohistochemical analysis of adhesive papillae of Clavelina lepadiformis (Müller, 1776 and Clavelina phlegraea (Salfi, 1929 (Tunicata, Ascidiacea

    Directory of Open Access Journals (Sweden)

    R Pennati

    2009-08-01

    Full Text Available Almost all ascidian larvae bear three mucus secreting and sensory organs, the adhesive papillae, at the anterior end of the trunk, which play an important role during the settlement phase. The morphology and the cellular composition of these organs varies greatly in the different species. The larvae of the Clavelina genus bear simple bulbous papillae, which are considered to have only a secretory function. We analysed the adhesive papillae of two species belonging to this genus, C. lepadiformis and C. phlegraea, by histological sections and by immunolocalisation of b-tubulin and serotonin, in order to better clarify the cellular composition of these organs.We demonstrated that they contain at least two types of neurons: central neurons, bearing microvilli, and peripheral ciliated neurons. Peripheral neurons of C. lepadiformis contain serotonin. We suggest that these two neurons play different roles during settlement: the central ones may be chemo- or mechanoreceptors that sense the substratum, and the peripheral ones may be involved in the mechanism that triggers metamorphosis.

  6. Cyanobacteria in Coral Reef Ecosystems: A Review

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    L. Charpy

    2012-01-01

    Full Text Available Cyanobacteria have dominated marine environments and have been reef builders on Earth for more than three million years (myr. Cyanobacteria still play an essential role in modern coral reef ecosystems by forming a major component of epiphytic, epilithic, and endolithic communities as well as of microbial mats. Cyanobacteria are grazed by reef organisms and also provide nitrogen to the coral reef ecosystems through nitrogen fixation. Recently, new unicellular cyanobacteria that express nitrogenase were found in the open ocean and in coral reef lagoons. Furthermore, cyanobacteria are important in calcification and decalcification. All limestone surfaces have a layer of boring algae in which cyanobacteria often play a dominant role. Cyanobacterial symbioses are abundant in coral reefs; the most common hosts are sponges and ascidians. Cyanobacteria use tactics beyond space occupation to inhibit coral recruitment. Cyanobacteria can also form pathogenic microbial consortia in association with other microbes on living coral tissues, causing coral tissue lysis and death, and considerable declines in coral reefs. In deep lagoons, coccoid cyanobacteria are abundant and are grazed by ciliates, heteroflagellates, and the benthic coral reef community. Cyanobacteria produce metabolites that act as attractants for some species and deterrents for some grazers of the reef communities.

  7. Pyridinoacridine alkaloids of marine origin: NMR and MS spectral data, synthesis, biosynthesis and biological activity

    Directory of Open Access Journals (Sweden)

    Louis P. Sandjo

    2015-09-01

    Full Text Available This review focuses on pyridoacridine-related metabolites as one biologically interesting group of alkaloids identified from marine sources. They are produced by marine sponges, ascidians and tunicates, and they are structurally comprised of four to eight fused rings including heterocycles. Acridine, acridone, dihydroacridine, and quinolone cores are features regularly found in these alkaloid skeletons. The lack of hydrogen atoms next to quaternary carbon atoms for two or three rings makes the chemical shift assignment a difficult task. In this regard, one of the aims of this review is the compilation of previously reported, pyridoacridine 13C NMR data. Observations have been made on the delocalization of electrons and the presence of some functional groups that lead to changes in the chemical shift of some carbon resonances. The lack of mass spectra information for these alkaloids due to the compactness of their structures is further discussed. Moreover, the biosynthetic pathways of some of these metabolites have been shown since they could inspire biomimetic synthesis. The synthesis routes used to prepare members of these marine alkaloids (as well as their analogues, which are synthesized for biological purposes are also discussed. Pyridoacridines were found to have a large spectrum of bioactivity and this review highlights and compares the pharmacophores that are responsible for the observed bioactivity.

  8. Tunicates: exploring the sea shores and roaming the open ocean. A tribute to Thomas Huxley.

    Science.gov (United States)

    Lemaire, Patrick; Piette, Jacques

    2015-06-01

    This review is a tribute to the remarkable contributions of Thomas Huxley to the biology of tunicates, the likely sister group of vertebrates. In 1851, the great biologist and philosopher published two landmark papers on pelagic tunicates in the Philosophical Transactions of the Royal Society. They were dedicated to the description of the adult anatomy and life cycle of thaliaceans and appendicularians, the pelagic relatives of ascidians. In the first part of this review, we discuss the novel anatomical observations and evolutionary hypotheses made by Huxley, which would have a lasting influence on tunicate biology. We also briefly comment on the more philosophical reflections of Huxley on individuality. In the second part, we stress the originality and relevance of past and future studies of tunicates in the resolution of major biological issues. In particular, we focus on the complex relationship between genotype and phenotype and the phenomenon of developmental system drift. We propose that more than 150 years after Huxley's papers, tunicate embryos are still worth studying in their own right, independently of their evolutionary proximity to vertebrates, as they provide original and crucial insights into the process of animal evolution. Tunicates are still at the forefront of biological research.

  9. Climate change and glacier retreat drive shifts in an Antarctic benthic ecosystem.

    Science.gov (United States)

    Sahade, Ricardo; Lagger, Cristian; Torre, Luciana; Momo, Fernando; Monien, Patrick; Schloss, Irene; Barnes, David K A; Servetto, Natalia; Tarantelli, Soledad; Tatián, Marcos; Zamboni, Nadia; Abele, Doris

    2015-11-01

    The Antarctic Peninsula (AP) is one of the three places on Earth that registered the most intense warming in the last 50 years, almost five times the global mean. This warming has strongly affected the cryosphere, causing the largest ice-shelf collapses ever observed and the retreat of 87% of glaciers. Ecosystem responses, although increasingly predicted, have been mainly reported for pelagic systems. However, and despite most Antarctic species being benthic, responses in the Antarctic benthos have been detected in only a few species, and major effects at assemblage level are unknown. This is probably due to the scarcity of baselines against which to assess change. We performed repeat surveys of coastal benthos in 1994, 1998, and 2010, analyzing community structure and environmental variables at King George Island, Antarctica. We report a marked shift in an Antarctic benthic community that can be linked to ongoing climate change. However, rather than temperature as the primary factor, we highlight the resulting increased sediment runoff, triggered by glacier retreat, as the potential causal factor. The sudden shift from a "filter feeders-ascidian domination" to a "mixed assemblage" suggests that thresholds (for example, of tolerable sedimentation) and alternative equilibrium states, depending on the reversibility of the changes, could be possible traits of this ecosystem. Sedimentation processes will be increasing under the current scenario of glacier retreat, and attention needs to be paid to its effects along the AP.

  10. First record of massive blooming of benthic diatoms and their association with megabenthic filter feeders on the shallow seafloor of an Antarctic Fjord: Does glacier melting fuel the bloom?

    Science.gov (United States)

    Ahn, In-Young; Moon, Hye-Won; Jeon, Misa; Kang, Sung-Ho

    2016-03-01

    We report a conspicuous benthic diatom bloom on an Antarctic fjord shallow seafloor, which has not been reported elsewhere in Antarctica. A thick and massive growth of benthic diatoms was covering or being entangled with a variety of common benthic megafauna such as stalked ascidians, sponges, tubedwelling polychaetes, gastropods, bryozoans, and others. This finding is an outcome of recent investigations on benthic communities in Marian Cove, King George Island, where glacier retreat has been proceeding quickly for the past several decades. Dominance of benthic diatoms during the austral summer has been frequently reported in shallow Antarctic nearshore waters, which in turn indicates their potential as a primary food item for secondary producers living in this harsh environment. However, previous blooming records of the benthic diatoms were primarily based on data from water column samples. We are the first to report observational evidence of shallow seafloor substrates, including the massive blooming of benthic diatoms and their associations with common benthic megafauna in an Antarctic fjord.

  11. Effects of fertilization distance on male gain curves in a free-spawning marine invertebrate: a combined empirical and theoretical approach.

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    Johnson, Sheri L; Yund, Philip O

    2009-12-01

    Male gain curves describe the relationship between allocation to sperm production and male reproductive success and are central to models of sex allocation in hermaphrodites. Sperm competition is expected to result in more linear gains and select for increased allocation. We hypothesized that high sperm production in passively mating systems may also be the result of selection to enhance the ability to fertilize distant ova. Consequently, we explored the effect of distance on male gain curves in a free-spawning colonial ascidian. The performance of focal males that varied in sperm production was assayed at three distances via microsatellite markers. An advection-diffusion model was used to estimate sperm concentration gradients, to predict male reproductive gain integrated across multiple downstream females, and explore effects of hydrodynamic conditions. As distance increased, male reproductive success decreased and empirical gain curves became increasingly linear. Our model predicted that the expected net gain curve is relatively insensitive to variation in flow regime and will saturate much more slowly than if only a single, nearby distance is considered. Thus, high levels of sperm production may enhance fitness both in competitive situations and with increasing fertilization distance, highlighting the need to consider distance effects when evaluating gain curves.

  12. Discovery of a marine bacterium producing 4-hydroxybenzoate and its alkyl esters, parabens.

    Science.gov (United States)

    Peng, Xue; Adachi, Kyoko; Chen, Choryu; Kasai, Hiroaki; Kanoh, Kaneo; Shizuri, Yoshikazu; Misawa, Norihiko

    2006-08-01

    Chemically synthesized 4-hydroxybenzoate (4HBA) is widely used in the chemical and electrical industries as a material for producing polymers such as those of the liquid crystal type. Its alkyl esters, called parabens, have been the most widely used preservatives by the food and cosmetic industries. We report here for the first time a microorganism, a marine bacterium, which biosynthesizes these petrochemical products. The marine bacterial strain, A4B-17, which was found to belong to the genus Microbulbifer on the basis of its rRNA and gyrB sequences, was isolated from an ascidian in the coastal waters of Palau. Strain A4B-17 was, surprisingly, found to produce 10 mg/liter of 4HBA, together with its butyl (24 mg/liter), heptyl (0.4 mg/liter), and nonyl (6 mg/liter) esters. We therefore characterized 23 other marine bacteria belonging to the genus Microbulbifer, which our institute had previously isolated from various marine environments, and found that these bacteria also produced 4HBA, although with low production levels (less than one-fifth of that produced by A4B-17). We also show that the alkyl esters of 4HBA produced by strain A4B-17 were effective in preventing the growth of yeasts, molds, and gram-positive bacteria.

  13. The cult of amphioxus in German Darwinism; or, our gelatinous ancestors in Naples' blue and balmy bay.

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    Hopwood, Nick

    2015-01-01

    Biologists having rediscovered amphioxus, also known as the lancelet or Branchiostoma, it is time to reassess its place in early Darwinist debates over vertebrate origins. While the advent of the ascidian-amphioxus theory and challenges from various competitors have been, documented, this article offers a richer account of the public appeal of amphioxus as a primitive ancestor. The focus is on how the 'German Darwin' Ernst Haeckel persuaded general magazine and newspaper readers to revere this "flesh of our flesh and blood of our blood", and especially on Das neue Laienbrevier des Haeckelismus (The new lay breviary of Haeckelism) by Moritz Reymond with cartoons by Fritz Steub. From the late 1870s these successful little books of verse introduced the Neapolitan discoveries that made the animal's name and satirized Haeckel's rise as high priest of its cult. One song is reproduced and translated here, with a contemporary "imitation" by the Canadian palaeontologist Edward John Chapman, and extracts from others. Predating the American "It's a long way from amphioxus" by decades, these rhymes dramatize neglected 'species politics' of Darwinism and highlight the roles of humour in negotiating evolution.

  14. Genetic Compatibility Underlies Benefits of Mate Choice in an External Fertilizer.

    Science.gov (United States)

    Aguirre, J David; Blows, Mark W; Marshall, Dustin J

    2016-05-01

    Mate choice is a common feature of sexually reproducing species. In sessile or sedentary external fertilizers, however, direct interactions between reproductive partners are minimal, and instead mate recognition and choice must occur at the level of gametes. It is common for some sperm and egg combinations to have higher fertilization success than others, but it remains unclear whether differences in fertilization reflect gamete-level mate choice (GMC) for paternal quality or parental compatibility. Here, we examine the mechanisms underlying GMC in an externally fertilizing ascidian. A manipulative mate-choice assay confirmed that offspring viability was greater in clutches where we allowed GMC than in clutches where we precluded GMC. A complementary quantitative genetic experiment then revealed that paternal quality effects were generally weaker than parental compatibility effects, particularly for the trait combination underlying the benefits of GMC. Overall, our data suggest that gametes that are more compatible at fertilization produce more viable offspring than gametes that are less compatible at fertilization. Therefore, although the regalia we typically associate with sexual selection are absent in external fertilizers, mechanisms that allow females to bias fertilization in favor of some males over others produce significant fitness benefits in organisms reproducing via the ancestral strategy.

  15. Nodal signalling and asymmetry of the nervous system.

    Science.gov (United States)

    Signore, Iskra A; Palma, Karina; Concha, Miguel L

    2016-12-19

    The role of Nodal signalling in nervous system asymmetry is still poorly understood. Here, we review and discuss how asymmetric Nodal signalling controls the ontogeny of nervous system asymmetry using a comparative developmental perspective. A detailed analysis of asymmetry in ascidians and fishes reveals a critical context-dependency of Nodal function and emphasizes that bilaterally paired and midline-unpaired structures/organs behave as different entities. We propose a conceptual framework to dissect the developmental function of Nodal as asymmetry inducer and laterality modulator in the nervous system, which can be used to study other types of body and visceral organ asymmetries. Using insights from developmental biology, we also present novel evolutionary hypotheses on how Nodal led the evolution of directional asymmetry in the brain, with a particular focus on the epithalamus. We intend this paper to provide a synthesis on how Nodal signalling controls left-right asymmetry of the nervous system.This article is part of the themed issue 'Provocative questions in left-right asymmetry'.

  16. Modelling distribution of marine benthos from hydroacoustics and underwater video

    Science.gov (United States)

    Holmes, K. W.; Van Niel, K. P.; Radford, B.; Kendrick, G. A.; Grove, S. L.

    2008-08-01

    Broad-scale mapping of marine benthos is required for marine resource management and conservation. This study combines textural derivatives based on bathymetry from multibeam hydroacoustics with underwater video observations to model and map sessile biota between 10- and 60-m water depth over 35 km 2 in Point Addis Marine National Park (MNP), Vic., Australia. Classification tree models and maps were developed for macroalgae (all types, mixed red algae, Ecklonia, and rhodoliths) and sessile invertebrates (all types, sponges, and ascidians). Model accuracy was tested on 25% of the video observation dataset reserved from modelling. Models fit well for most macroalgae categories (correct classification rates of 67-84%), but are not as good for sessile invertebrate classes (correct classification rates of 57-62%). The poor fit of the sessile invertebrate models may be the combined result of grouping organisms with different environmental requirements and the effect of false absences recorded during video interpretation due to poor image quality. Probability maps, binary single-class maps, and multi-class maps supply spatially explicit, detailed information on the distribution of sessile benthic biota within the MNP and provide information at a landscape-scale for ecological investigations and marine management.

  17. Marine actinobacteria associated with marine organisms and their potentials in producing pharmaceutical natural products.

    Science.gov (United States)

    Valliappan, Karuppiah; Sun, Wei; Li, Zhiyong

    2014-09-01

    Actinobacteria are ubiquitous in the marine environment, playing an important ecological role in the recycling of refractory biomaterials and producing novel natural products with pharmic applications. Actinobacteria have been detected or isolated from the marine creatures such as sponges, corals, mollusks, ascidians, seaweeds, and seagrass. Marine organism-associated actinobacterial 16S rRNA gene sequences, i.e., 3,003 sequences, deposited in the NCBI database clearly revealed enormous numbers of actinobacteria associated with marine organisms. For example, RDP classification of these sequences showed that 112 and 62 actinobacterial genera were associated with the sponges and corals, respectively. In most cases, it is expected that these actinobacteria protect the host against pathogens by producing bioactive compounds. Natural products investigation and functional gene screening of the actinobacteria associated with the marine organisms revealed that they can synthesize numerous natural products including polyketides, isoprenoids, phenazines, peptides, indolocarbazoles, sterols, and others. These compounds showed anticancer, antimicrobial, antiparasitic, neurological, antioxidant, and anti-HIV activities. Therefore, marine organism-associated actinobacteria represent an important resource for marine drugs. It is an upcoming field of research to search for novel actinobacteria and pharmaceutical natural products from actinobacteria associated with the marine organisms. In this review, we attempt to summarize the present knowledge on the diversity and natural products production of actinobacteria associated with the marine organisms, based on the publications from 1991 to 2013.

  18. Immunohistochemical analysis of adhesive papillae of Clavelina lepadiformis (Müller, 1776 and Clavelina phlegraea (Salfi, 1929 (Tunicata, Ascidiacea

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    G Zega

    2009-03-01

    Full Text Available Almost all ascidian larvae bear three mucus secreting and sensory organs, the adhesive papillae, at the anterior end of the trunk, which play an important role during the settlement phase. The morphology and the cellular composition of these organs varies greatly in the different species. The larvae of the Clavelina genus bear simple bulbous papillae, which are considered to have only a secretory function. We analysed the adhesive papillae of two species belonging to this genus, C. lepadiformis and C. phlegraea, by histological sections and by immunolocalisation of b-tubulin and serotonin, in order to better clarify the cellular composition of these organs.We demonstrated that they contain at least two types of neurons: central neurons, bearing microvilli, and peripheral ciliated neurons. Peripheral neurons of C. lepadiformis contain serotonin. We suggest that these two neurons play different roles during settlement: the central ones may be chemo- or mechanoreceptors that sense the substratum, and the peripheral ones may be involved in the mechanism that triggers metamorphosis.

  19. Role of hemocytes in invertebrate adult neurogenesis and brain repair

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    PG Chaves da Silva

    2015-05-01

    Full Text Available The repair of lesions of the central nervous system (CNS varies widely throughout the animal kingdom. At the level of neuronal replacement lie the major differences in CNS regeneration. At one extreme are the amniote vertebrates (reptile, avian and mammalian groups, which have very limited capacity for neuronal replacement, and therefore for neural regeneration; at the other extreme, animals such as planarians (flatworms and colonial tunicates can repair their entire CNS after major injuries. These differences can be attributed to the abundance of multipotent and/or pluripotent stem cells and/or undifferentiated precursors among the general cell population. In this review we discuss recent advancements in knowledge of regeneration of the CNS of invertebrates. We focus on ascidians, which are a sister group of vertebrates, but we also address other invertebrate groups. Because neurogenesis is central to the events that allow regeneration of the adult CNS, we address this issue focusing on crustaceans, which have provided a paradigm to study the mechanisms underlying this phenomenon. The attraction of hemocytes toward a neurogenic niche and respecification of these cells toward a neural fate has been strongly suggested. Based on recent and emerging research, we suggest that cells of the blood lineage are not only associated with the roles that are generally attributed to them, but are the cells that either signal other cell types to differentiate into neural cells, or even eventually themselves transdifferentiate into neural cells.

  20. Characteristics of the mesophotic megabenthic assemblages of the vercelli seamount (north tyrrhenian sea.

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    Marzia Bo

    Full Text Available The biodiversity of the megabenthic assemblages of the mesophotic zone of a Tyrrhenian seamount (Vercelli Seamount is described using Remotely Operated Vehicle (ROV video imaging from 100 m depth to the top of the mount around 61 m depth. This pinnacle hosts a rich coralligenous community characterized by three different assemblages: (i the top shows a dense covering of the kelp Laminaria rodriguezii; (ii the southern side biocoenosis is mainly dominated by the octocorals Paramuricea clavata and Eunicella cavolinii; while (iii the northern side of the seamount assemblage is colonized by active filter-feeding organisms such as sponges (sometimes covering 100% of the surface with numerous colonies of the ascidian Diazona violacea, and the polychaete Sabella pavonina. This study highlights, also for a Mediterranean seamount, the potential role of an isolated rocky peak penetrating the euphotic zone, to work as an aggregating structure, hosting abundant benthic communities dominated by suspension feeders, whose distribution may vary in accordance to the geomorphology of the area and the different local hydrodynamic conditions.

  1. Contribution to the knowledge of cotylean flatworms (Turbellaria, Polycladida) from Iranian coasts: Introducing a new species, with remarks on new records.

    Science.gov (United States)

    Maghsoudlou, Abdolvahab; Rahimian, Hassan

    2014-09-08

    Very little information is available regarding marine free-living flatworms not only from Iran, but throughout the countries surrounding the Persian Gulf and the Gulf of Oman. The present study first introduces a new euryleptid species, and then reports four pseudocerotid polyclads which inhabit Iranian shallow rocky shores of the Persian Gulf and the Gulf of Oman. Maritigrella makranica sp. nov. is characterized dorsally by a medial cream or white reticulated appearance containing pale orange spots in a honeycomb pattern, a distinct orange submarginal band around the entire body margin and between the marginal tentacles, black spots scattered around mid-dorsal surface, becoming more sparse on raised median region and towards body margin, surrounded by a dark-grey halo around the body midline and orange-black halo towards margin. Three of the four pseudocerotids species belonging to the genera Pseudobiceros Faubel, 1984; Pseudoceros Lang, 1884; and Thysanozoon Grube, 1840, are new records for the studied areas, while the other has been reported in the Persian Gulf previously. Comments on Iranian species are provided and associations of flatworms with ascidians and sponges were observed. 

  2. Specific sulfation and glycosylation - a structural combination for the anticoagulation of marine carbohydrates

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    Vitor Hugo Pomin

    2014-03-01

    Full Text Available Based on considered achievements of the last 25 years, specific combinations of sulfation patterns and glycosylation types have been proved to be key structural players for the anticoagulant activity of certain marine glycans. These conclusions were obtained from comparative and systematic analyses on the structure-anticoagulation relationships of chemically well-defined sulfated polysaccharides of marine invertebrates and red algae. These sulfated polysaccharides are known as sulfated fucans (SFs, sulfated galactans (SGs and glycosaminoglycans (GAGs. The structural combinations necessary for the anticoagulant activities are the 2-sulfation in α-L-SGs, the 2,4-di-sulfation in α-L-fucopyranosyl units found as composing units of certain sea-urchin and sea-cucumber linear SFs, or as branching units of the fucosylated chondroitin sulfate, a unique GAG from sea-cucumbers. Another unique GAG type from marine organisms is the dermatan sulfate isolated from ascidians. The high levels of 4-sulfation at the galactosamine units combined with certain levels of 2-sulfation at the iduronic acid units is the anticoagulant structural requirements of these GAGs. When the backbones of red algal SGs are homogeneous, the anticoagulation is proportionally dependent of their sulfation content. Finally, 4-sulfation was observed to be the structural motif required to enhance the inhibition of thrombin via heparin cofactor-II by invertebrate SFs.

  3. Specific sulfation and glycosylation-a structural combination for the anticoagulation of marine carbohydrates.

    Science.gov (United States)

    Pomin, Vitor H; Mourão, Paulo A S

    2014-01-01

    Based on considered achievements of the last 25 years, specific combinations of sulfation patterns and glycosylation types have been proved to be key structural players for the anticoagulant activity of certain marine glycans. These conclusions were obtained from comparative and systematic analyses on the structure-anticoagulation relationships of chemically well-defined sulfated polysaccharides of marine invertebrates and red algae. These sulfated polysaccharides are known as sulfated fucans (SFs), sulfated galactans (SGs) and glycosaminoglycans (GAGs). The structural combinations necessary for the anticoagulant activities are the 2-sulfation in α-L-SGs, the 2,4-di-sulfation in α-L-fucopyranosyl units found as composing units of certain sea-urchin and sea-cucumber linear SFs, or as branching units of the fucosylated chondroitin sulfate, a unique GAG from sea-cucumbers. Another unique GAG type from marine organisms is the dermatan sulfate isolated from ascidians. The high levels of 4-sulfation at the galactosamine units combined with certain levels of 2-sulfation at the iduronic acid units is the anticoagulant structural requirements of these GAGs. When the backbones of red algal SGs are homogeneous, the anticoagulation is proportionally dependent of their sulfation content. Finally, 4-sulfation was observed to be the structural motif required to enhance the inhibition of thrombin via heparin cofactor-II by invertebrate SFs.

  4. Macrofauna associated to Mycale microsigmatosa (Porifera, Demospongiae) in Rio de Janeiro State, SE Brazil

    Science.gov (United States)

    Ribeiro, Suzi M.; Omena, Elianne P.; Muricy, Guilherme

    2003-08-01

    The macrofauna (endo- and epi-biotic) associated to the sponge Mycale ( Carmia) microsigmatosa Arndt, 1927 was studied at three sites in Rio de Janeiro State, Brazil (Arraial do Cabo, Niterói, and Rio de Janeiro). A total of 2235 individuals (over 1 mm long) of 75 invertebrate species were found associated to 19 specimens of the sponge. The most abundant and diverse taxa were the crustaceans (83%, 31 spp.), polychetes (10%, 18 spp.), and molluscs (3.7%, 15 spp.). Cnidarians, platyhelminthes, ascidians, echinoderms, pycnogonids, bryozoans, and sponges were also represented. Amphipod crustaceans were the dominant group, comprising 61% of all individuals collected. Species richness and abundance of associated fauna were highly correlated with sponge volume, but diversity and evenness were not. The site of collection influenced the species composition of the fauna associated to M. microsigmatosa but did not change significantly its diversity, abundance, richness, and dominance patterns of higher taxa. Pregnant females and juvenile stages of 29% of the species associated, including crustaceans, molluscs, echinoderms, and pycnogonids were frequently found inside M. microsigmatosa. Although many of these organisms do occur and reproduce in other habitats outside the sponge as well, M. microsigmatosa is also important for their reproduction and survivorship, thus contributing for the maintenance of biodiversity in Southwestern Atlantic sublittoral rocky shores.

  5. New Mediterranean Biodiversity Records (December 2012

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    M. THESSALOU-LEGAKI

    2013-01-01

    Full Text Available This paper presents records extending or confirming the distribution of Mediterranean species. Three alien algae are included, namely Codium taylorii reported for the first time from the Aegean and Turkey (Izmir Gulf, Caulerpa racemosa var. cylindracea (Karpathos and Chalki Isl., Aegean Sea and Ganonema farinosum (Karpathos Isl., Aegean Sea. As far as animals are concerned, Litarachna divergens (Acari: Hydrachnidia was recorded (Side, Eastern Mediterranean and represents a new amendment at genus level for Turkish fauna. Other invertebrates include alien species such as the crabs Dyspanopeus sayi (Lago Fusaro, SW Italy, Percnon gibbesi (Larnaca, Cyprus; Karpathos and Chalki Isl., Aegean Sea and Callinectes sapidus (Voda estuary, NW Greece, the nudibranch Aplysia dactylomela (Boka Kotorska Bay, Montenegro, the gastropod Conomurex persicus (Karpathos and ChalkiIsl., Aegean Sea and the bryozoan Electra tenella (Livorno harbour and Messina Straits area. The alien fish Siganus luridus, Siganus rivulatus, Fistularia commersonii, Sphyraena chrysotaenia and Sargocentron rubrum are also reported from the islands of Karpathos and Chalki, and Pteragogus pelycus from Heraklion Bay, Crete. In addition, new localities for four rare Mediterranean inhabitants are given: the cephalopod Thysanoteuthis rhombus (NW Sardinia and the fish: Lampris guttatus (Calabria, S Italy, Petromyzon marinus (Gokova Bay and Remora australis (Saronikos Gulf, while the opisthobranch gastropod Cerberilla bernadettae is reported for the first time from the E Mediterranean (Cyprus. Finally, three species of the Aegean ascidiofauna are recorded for the first time: Lissoclinum perforatum, Ciona roulei and Ecteinascidia turbinata. Furthermore, it was established that Phallusia nigra has extended its distributional range to the north of the Aegean Sea.

  6. The atypical calpains: evolutionary analyses and roles in Caenorhabditis elegans cellular degeneration.

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    Peter I Joyce

    Full Text Available The calpains are physiologically important Ca(2+-activated regulatory proteases, which are divided into typical or atypical sub-families based on constituent domains. Both sub-families are present in mammals, but our understanding of calpain function is based primarily on typical sub-family members. Here, we take advantage of the model organism Caenorhabditis elegans, which expresses only atypical calpains, to extend our knowledge of the phylogenetic evolution and function of calpains. We provide evidence that a typical human calpain protein with a penta EF hand, detected using custom profile hidden Markov models, is conserved in ancient metazoans and a divergent clade. These analyses also provide evidence for the lineage-specific loss of typical calpain genes in C. elegans and Ciona, and they reveal that many calpain-like genes lack an intact catalytic triad. Given the association between the dysregulation of typical calpains and human degenerative pathologies, we explored the phenotypes, expression profiles, and consequences of inappropriate reduction or activation of C. elegans atypical calpains. These studies show that the atypical calpain gene, clp-1, contributes to muscle degeneration and reveal that clp-1 activity is sensitive to genetic manipulation of [Ca(2+](i. We show that CLP-1 localizes to sarcomeric sub-structures, but is excluded from dense bodies (Z-disks. We find that the muscle degeneration observed in a C. elegans model of dystrophin-based muscular dystrophy can be suppressed by clp-1 inactivation and that nemadipine-A inhibition of the EGL-19 calcium channel reveals that Ca(2+ dysfunction underlies the C. elegans MyoD model of myopathy. Taken together, our analyses highlight the roles of calcium dysregulation and CLP-1 in muscle myopathies and suggest that the atypical calpains could retain conserved roles in myofilament turnover.

  7. The atypical calpains: evolutionary analyses and roles in Caenorhabditis elegans cellular degeneration.

    Science.gov (United States)

    Joyce, Peter I; Satija, Rahul; Chen, Maozi; Kuwabara, Patricia E

    2012-01-01

    The calpains are physiologically important Ca(2+)-activated regulatory proteases, which are divided into typical or atypical sub-families based on constituent domains. Both sub-families are present in mammals, but our understanding of calpain function is based primarily on typical sub-family members. Here, we take advantage of the model organism Caenorhabditis elegans, which expresses only atypical calpains, to extend our knowledge of the phylogenetic evolution and function of calpains. We provide evidence that a typical human calpain protein with a penta EF hand, detected using custom profile hidden Markov models, is conserved in ancient metazoans and a divergent clade. These analyses also provide evidence for the lineage-specific loss of typical calpain genes in C. elegans and Ciona, and they reveal that many calpain-like genes lack an intact catalytic triad. Given the association between the dysregulation of typical calpains and human degenerative pathologies, we explored the phenotypes, expression profiles, and consequences of inappropriate reduction or activation of C. elegans atypical calpains. These studies show that the atypical calpain gene, clp-1, contributes to muscle degeneration and reveal that clp-1 activity is sensitive to genetic manipulation of [Ca(2+)](i). We show that CLP-1 localizes to sarcomeric sub-structures, but is excluded from dense bodies (Z-disks). We find that the muscle degeneration observed in a C. elegans model of dystrophin-based muscular dystrophy can be suppressed by clp-1 inactivation and that nemadipine-A inhibition of the EGL-19 calcium channel reveals that Ca(2+) dysfunction underlies the C. elegans MyoD model of myopathy. Taken together, our analyses highlight the roles of calcium dysregulation and CLP-1 in muscle myopathies and suggest that the atypical calpains could retain conserved roles in myofilament turnover.

  8. Evolution of the insulin-like growth factor binding protein (IGFBP) family.

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    Daza, Daniel Ocampo; Sundström, Görel; Bergqvist, Christina A; Duan, Cunming; Larhammar, Dan

    2011-06-01

    The evolution of the IGF binding protein (IGFBP) gene family has been difficult to resolve. Both chromosomal and serial duplications have been suggested as mechanisms for the expansion of this gene family. We have identified and annotated IGFBP sequences from a wide selection of vertebrate species as well as Branchiostoma floridae and Ciona intestinalis. By combining detailed sequence analysis with sequence-based phylogenies and chromosome information, we arrive at the following scenario: the ancestral chordate IGFBP gene underwent a local gene duplication, resulting in a gene pair adjacent to a HOX cluster. Subsequently, the gene family expanded in the two basal vertebrate tetraploidization (2R) resulting in the six IGFBP types that are presently found in placental mammals. The teleost fish ancestor underwent a third tetraploidization (3R) that further expanded the IGFBP repertoire. The five sequenced teleost fish genomes retain 9-11 of IGFBP genes. This scenario is supported by the phylogenies of three adjacent gene families in the HOX gene regions, namely the epidermal growth factor receptors (EGFR) and the Ikaros and distal-less (DLX) transcription factors. Our sequence comparisons show that several important structural components in the IGFBPs are ancestral vertebrate features that have been maintained in all orthologs, for instance the integrin interaction motif Arg-Gly-Asp in IGFBP-2. In contrast, the Arg-Gly-Asp motif in IGFBP-1 has arisen independently in mammals. The large degree of retention of IGFBP genes after the ancient expansion of the gene family strongly suggests that each gene evolved distinct and important functions early in vertebrate evolution.

  9. Distribution and diversity of tunicates utilizing eelgrass as substrate in the western North Atlantic between 39° and 47° north latitude (New Jersey to Newfoundland)

    Science.gov (United States)

    Carman, M R; Colarusso, Phillip D; Nelson, Eric P; Grunden, David W; Wong, Melisa C; McKenzie, Cynthia; Matheson, Kyle; Davidson, Jeffrey G.; Fox, Sophia; Neckles, Hilary A.; Bayley, Holly; Schott, Stephen; Dijkstra, Jennifer A; Stewart-Clark, Sarah

    2016-01-01

    Seagrass meadows are ecologically important habitats that are declining globally at an accelerating rate due to natural and anthropogenic stressors. Their decline is a serious concern as this habitat provides many ecosystem services. Eelgrass (Zostera marina) is the dominant seagrass species in the western North Atlantic. It has recently been established that invasive tunicate species possibly threaten the health of eelgrass beds. Colonization of eelgrass leaves by tunicates can inhibit eelgrass growth and may cause shoot mortality. To document the distribution and diversity of tunicate species that attach to eelgrass in the western North Atlantic, we surveyed twenty-one eelgrass sites from New Jersey to Newfoundland. Eight species of tunicates were found to be colonizing eelgrass, of which 6 are considered invasive. Botrylloides violaceus and Botryllus schlosseri were most commonly attached to eelgrass, with B. schlosseri having the largest latitudinal range of any species. Tunicate faunas attached to eelgrass were less diverse north of Gloucester, Massachusetts, where individual survey sites exhibited two species at most and only 4 of the 8 species observed in this study. Percent tunicate cover on eelgrass tended to fall within the 1–25 range, with occasional coverage up to >75–100. Density of eelgrass was highly variable among sites, ranging from <1 to 820 shoots/m². The solitary tunicate Ciona intestinalis was only found on eelgrass at the highest latitude sampled, in Newfoundland, where it is a new invader. The tunicates observed in this study, both solitary and colonial, are viable when attached to eelgrass and pose a potential threat to overgrow and weaken seagrass shoots and reduce the sustainability of seagrass meadows.

  10. ESTADO NACIONAL Y COMUNIDAD ANDINA. DISCIPLINAMIENTO Y ARTICULACIÓN SOCIAL EN ARICA, 1880-1929

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    Claudio Aguirre Munizaga

    2011-06-01

    Full Text Available El presente estudio desarrolla una aproximación historiográfica al período conocido comúnmente como de chilenización del norte de Chile, que comprende los años 1880-1929. En él se analiza la relación entre la articulación social de la sociedad andina y el disciplinamiento del Estado nacional chileno, en el espacio sociocultural que en la actualidad comprende el sector rural de la provincia de Arica, con sus valles bajos, precordillera y sector altiplánico. El estudio se posi-ciona en un análisis historiográfico de interés regional y nacional, a partir de la revisión de fuentes históricas provenientes de archivos locales, donde se aborda históricamente la caracterización de la estructura política, económica, social y cultural en este territorio.This study develops an historiographical approach to the period commonly known as the Chilenization of northern Chile covering the years between 1880-1929. It examines the relationship of the social organization of Andean society with the Chilean State disciplining of the socio-cultural space including the current rural sector in the province of Arica with its low valleys, foothills and Altiplano sector. The study is a historiographical analysis of regional and national interest, using historical sources from local archives that deal with the historical characterization of the political, economic, social and cultural structures in this area.

  11. Identifying single copy orthologs in Metazoa.

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    Christopher J Creevey

    2011-12-01

    Full Text Available The identification of single copy (1-to-1 orthologs in any group of organisms is important for functional classification and phylogenetic studies. The Metazoa are no exception, but only recently has there been a wide-enough distribution of taxa with sufficiently high quality sequenced genomes to gain confidence in the wide-spread single copy status of a gene.Here, we present a phylogenetic approach for identifying overlooked single copy orthologs from multigene families and apply it to the Metazoa. Using 18 sequenced metazoan genomes of high quality we identified a robust set of 1,126 orthologous groups that have been retained in single copy since the last common ancestor of Metazoa. We found that the use of the phylogenetic procedure increased the number of single copy orthologs found by over a third more than standard taxon-count approaches. The orthologs represented a wide range of functional categories, expression profiles and levels of divergence.To demonstrate the value of our set of single copy orthologs, we used them to assess the completeness of 24 currently published metazoan genomes and 62 EST datasets. We found that the annotated genes in published genomes vary in coverage from 79% (Ciona intestinalis to 99.8% (human with an average of 92%, suggesting a value for the underlying error rate in genome annotation, and a strategy for identifying single copy orthologs in larger datasets. In contrast, the vast majority of EST datasets with no corresponding genome sequence available are largely under-sampled and probably do not accurately represent the actual genomic complement of the organisms from which they are derived.

  12. Genomic analysis of the TRIM family reveals two groups of genes with distinct evolutionary properties

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    Fontanella Bianca

    2008-08-01

    Full Text Available Abstract Background The TRIM family is composed of multi-domain proteins that display the Tripartite Motif (RING, B-box and Coiled-coil that can be associated with a C-terminal domain. TRIM genes are involved in ubiquitylation and are implicated in a variety of human pathologies, from Mendelian inherited disorders to cancer, and are also involved in cellular response to viral infection. Results Here we defined the entire human TRIM family and also identified the TRIM sets of other vertebrate (mouse, rat, dog, cow, chicken, tetraodon, and zebrafish and invertebrate species (fruitfly, worm, and ciona. By means of comparative analyses we found that, after assembly of the tripartite motif in an early metazoan ancestor, few types of C-terminal domains have been associated with this module during evolution and that an important increase in TRIM number occurred in vertebrate species concomitantly with the addition of the SPRY domain. We showed that the human TRIM family is split into two groups that differ in domain structure, genomic organization and evolutionary properties. Group 1 members present a variety of C-terminal domains, are highly conserved among vertebrate species, and are represented in invertebrates. Conversely, group 2 is absent in invertebrates, is characterized by the presence of a C-terminal SPRY domain and presents unique sets of genes in each mammal examined. The generation of independent sets of group 2 genes is also evident in the other vertebrate species. Comparing the murine and human TRIM sets, we found that group 1 and 2 genes evolve at different speeds and are subject to different selective pressures. Conclusion We found that the TRIM family is composed of two groups of genes with distinct evolutionary properties. Group 2 is younger, highly dynamic, and might act as a reservoir to develop novel TRIM functions. Since some group 2 genes are implicated in innate immune response, their evolutionary features may account for

  13. Cloning, characterization and functional expression of Taenia solium 17 beta-hydroxysteroid dehydrogenase.

    Science.gov (United States)

    Aceves-Ramos, A; de la Torre, P; Hinojosa, L; Ponce, A; García-Villegas, R; Laclette, J P; Bobes, R J; Romano, M C

    2014-07-01

    The 17β-hydroxysteroid dehydrogenases (17β-HSD) are key enzymes involved in the formation (reduction) and inactivation (oxidation) of sex steroids. Several types have been found in vertebrates including fish, as well as in invertebrates like Caenorhabditis elegans, Ciona intestinalis and Haliotis diversicolor supertexta. To date limited information is available about this enzyme in parasites. We showed previously that Taenia solium cysticerci are able to synthesize sex steroid hormones in vitro when precursors are provided in the culture medium. Here, we identified a T. solium 17β-HSD through in silico blast searches in the T. solium genome database. This coding sequence was amplified by RT-PCR and cloned into the pcDNA 3.1(+) expression vector. The full length cDNA contains 957bp, corresponding to an open reading frame coding for 319 aa. The highest identity (84%) at the protein level was found with the Echinococcus multilocularis 17β-HSD although significant similarities were also found with other invertebrate and vertebrate 17β-HSD sequences. The T. solium Tsol-17βHSD belongs to the short-chain dehydrogenase/reductase (SDR) protein superfamily. HEK293T cells transiently transfected with Tsol17β-HSD induced expression of Tsol17β-HSD that transformed 3H-androstenedione into testosterone. In contrast, 3H-estrone was not significantly transformed into estradiol. In conclusion, T. solium cysticerci express a 17β-HSD that catalyzes the androgen reduction. The enzyme belongs to the short chain dehydrogenases/reductase family and shares motifs and activity with the type 3 enzyme of some other species.

  14. A study of helical and planar waves on sea urchin sperm flagella, with a theory of how they are generated.

    Science.gov (United States)

    Woolley, D M; Vernon, G G

    2001-04-01

    previously for spermatozoa of Ciona intestinalis and of the quail Coturnix coturnix.

  15. Functional mapping of cannabinoid receptor homologs in mammals, other vertebrates, and invertebrates.

    Science.gov (United States)

    McPartland, John M; Glass, Michelle

    2003-07-17

    Over the past decade, several putative homologs of cannabinoid receptors (CBRs) have been identified by homology screening. Homology screening utilizes sequence alignment search engines to recognize homologs. We investigated these putative CBR homologs further by 'functional mapping' of their deduced amino acid sequences. The entire pharmacophore of a CBR has not yet been elucidated, but point-mutation studies have identified over 20 amino acid residues that impart CBR specificity for ligand recognition and/or signal transduction. Twenty point-mutation studies were used to construct a CBR functionality matrix. Sixteen putative CBR homologs were then mapped over the matrix. Several putative homologs did not hold up to this analysis: human GPR3, GPR6, GPR12, and Caenorhabditis elegans C02H7.2 expressed a series of crippling substitutions in the matrix, strongly suggesting they do not encode functional CBRs. Mapping the contested leech (Hirudo medicinalis) CBR sequence suggests that it encodes a functional CB1; it expresses fewer substitutions than the sea squirt (Ciona intestinalis) CB1 sequence. Mapping a putative CB2 ortholog in the puffer fish (Fugu rubripes T012234) suggests it may encode a CBR other than CB2. These findings are consistent with the lack of experimental data proving these putative CBRs have affinity for cannabinoid ligands. Matrix analysis also reveals that SR144528, a 'CB2-specific' synthetic antagonist, has affinity for non-mammalian CB1 receptors, and that L3.45 appears to be CB2-specific, its cognate in CB1 receptors is F3.45. In conclusion, functional mapping, utilizing point-mutation studies, may improve the specificity of homology screening performed by sequence alignment search engines.

  16. Evolutionary Analysis and Classification of OATs, OCTs, OCTNs, and Other SLC22 Transporters: Structure-Function Implications and Analysis of Sequence Motifs.

    Science.gov (United States)

    Zhu, Christopher; Nigam, Kabir B; Date, Rishabh C; Bush, Kevin T; Springer, Stevan A; Saier, Milton H; Wu, Wei; Nigam, Sanjay K

    2015-01-01

    The SLC22 family includes organic anion transporters (OATs), organic cation transporters (OCTs) and organic carnitine and zwitterion transporters (OCTNs). These are often referred to as drug transporters even though they interact with many endogenous metabolites and signaling molecules (Nigam, S.K., Nature Reviews Drug Discovery, 14:29-44, 2015). Phylogenetic analysis of SLC22 supports the view that these transporters may have evolved over 450 million years ago. Many OAT members were found to appear after a major expansion of the SLC22 family in mammals, suggesting a physiological and/or toxicological role during the mammalian radiation. Putative SLC22 orthologs exist in worms, sea urchins, flies, and ciona. At least six groups of SLC22 exist. OATs and OCTs form two Major clades of SLC22, within which (apart from Oat and Oct subclades), there are also clear Oat-like, Octn, and Oct-related subclades, as well as a distantly related group we term "Oat-related" (which may have different functions). Based on available data, it is arguable whether SLC22A18, which is related to bacterial drug-proton antiporters, should be assigned to SLC22. Disease-causing mutations, single nucleotide polymorphisms (SNPs) and other functionally analyzed mutations in OAT1, OAT3, URAT1, OCT1, OCT2, OCTN1, and OCTN2 map to the first extracellular domain, the large central intracellular domain, and transmembrane domains 9 and 10. These regions are highly conserved within subclades, but not between subclades, and may be necessary for SLC22 transporter function and functional diversification. Our results not only link function to evolutionarily conserved motifs but indicate the need for a revised sub-classification of SLC22.

  17. The synapsin gene family in basal chordates: evolutionary perspectives in metazoans

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    De Bernardi Fiorenza

    2010-01-01

    Full Text Available Abstract Background Synapsins are neuronal phosphoproteins involved in several functions correlated with both neurotransmitter release and synaptogenesis. The comprehension of the basal role of the synapsin family is hampered in vertebrates by the existence of multiple synapsin genes. Therefore, studying homologous genes in basal chordates, devoid of genome duplication, could help to achieve a better understanding of the complex functions of these proteins. Results In this study we report the cloning and characterization of the Ciona intestinalis and amphioxus Branchiostoma floridae synapsin transcripts and the definition of their gene structure using available C. intestinalis and B. floridae genomic sequences. We demonstrate the occurrence, in both model organisms, of a single member of the synapsin gene family. Full-length synapsin genes were identified in the recently sequenced genomes of phylogenetically diverse metazoans. Comparative genome analysis reveals extensive conservation of the SYN locus in several metazoans. Moreover, developmental expression studies underline that synapsin is a neuronal-specific marker in basal chordates and is expressed in several cell types of PNS and in many, if not all, CNS neurons. Conclusion Our study demonstrates that synapsin genes are metazoan genes present in a single copy per genome, except for vertebrates. Moreover, we hypothesize that, during the evolution of synapsin proteins, new domains are added at different stages probably to cope up with the increased complexity in the nervous system organization. Finally, we demonstrate that protochordate synapsin is restricted to the post-mitotic phase of CNS development and thereby is a good marker of postmitotic neurons.

  18. 黄河口海域无脊椎动物群落结构及其变化%Community structure of invertebrate and its change in Huanghe (Yellow River) Estuary

    Institute of Scientific and Technical Information of China (English)

    张焕君; 李凡; 丛日翔; 丛旭日; 任中华; 吕振波

    2014-01-01

    根据2012年5月、6月、7月上旬、7月下旬、8月、9月在黄河口海域进行的3断面15站位弓子网调查数据,对该海域无脊椎动物群落组成、优势种、生物量、多样性、群落相似性等群落特征进行了研究。结果表明,调查共出现无脊椎动物45种,隶属于9目29科39属,各航次调查种类数在28种至35种之间。纵肋织纹螺(Nassarius variciferus)、口虾蛄(Oratosquilla oratoria)、艾氏活额寄居蟹(Diogenes edwardsii)、葛氏长臂虾(Palaemon gravieri)和扁玉螺(Neverita didyma)是黄河口无脊椎动物群落的主要优势种。调查期间生物量和丰度的变化趋势基本相似,均呈现下降-上升-下降的趋势,生物量最高值出现在8月,丰度最高值出现在7月下旬。各航次调查Shannon-Wiener多样性在1.482~1.719,5月最低,6月最高。Bray-Curtis相似性和ANOSIM相似性分析表明相近航次间群落相似性较高,5月、6月群落与8月、9月群落差异显著。根据研究结果,可以得出以下结论:1)黄河口无脊椎动物群落以小型、低质种类为主,与20世纪80年代相比,资源质量进一步下降;2)与20世纪80年代相比,生物量月间分布发生明显变化;3)与断面A(距河口10 km)、断面C(距河口40 km)相比,断面B(距河口20 km)无脊椎动物生物量和多样性在各航次间波动剧烈且规律性较差,表明断面 B 的无脊椎动物群落受黄河水沙输入影响更大;4)调水调沙虽对黄河口无脊椎动物群落结构产生一定程度的影响,但不是导致无脊椎动物群落更替的主要因素。%The Yellow River is the largest river in north China which greatly affects the environment of Bohai Sea. The freshwater input and suspended sediments have sustained the morphology and ecology of the river mouth, located in the northeastern modern Yellow River subaerial delta and was formed after the Yellow River shifted again at the north bank of the Qingshuigou course in June

  19. The substantial first impact of bottom fishing on rare biodiversity hotspots: a dilemma for evidence-based conservation.

    Science.gov (United States)

    Cook, Robert; Fariñas-Franco, Jose M; Gell, Fiona R; Holt, Rohan H F; Holt, Terry; Lindenbaum, Charles; Porter, Joanne S; Seed, Ray; Skates, Lucie R; Stringell, Thomas B; Sanderson, William G

    2013-01-01

    This study describes the impact of the first passage of two types of bottom-towed fishing gear on rare protected shellfish-reefs formed by the horse mussel Modiolus modiolus (L.). One of the study sites was trawled and the other was scallop-dredged. Divers collected HD video imagery of epifauna from quadrats at the two study sites and directed infaunal samples from one site. The total number of epifaunal organisms was significantly reduced following a single pass of a trawl (90%) or scallop dredge (59%), as was the diversity of the associated community and the total number of M. modiolus at the trawled site. At both sites declines in anthozoans, hydrozoans, bivalves, echinoderms and ascidians accounted for most of the change. A year later, no recovery was evident at the trawled site and significantly fewer infaunal taxa (polychaetes, malacostracans, bivalves and ophuroids) were recorded in the trawl track. The severity of the two types of impact reflected the undisturbed status of the habitats compared to previous studies. As a 'priority habitat' the nature of the impacts described on M. modiolus communities are important to the development of conservation management policy and indicators of condition in Marine Protected Areas (EU Habitats Directive) as well as indicators of 'Good Environmental Status' under the European Union Marine Strategy Framework Directive. Conservation managers are under pressure to support decisions with good quality evidence. Elsewhere, indirect studies have shown declines of M. modiolus biogenic communities in fishing grounds. However, given the protected status of the rare habitat, premeditated demonstration of direct impact is unethical or illegal in Marine Protected Areas. This study therefore provides a unique opportunity to investigate the impact from fishing gear whilst at the same time reflecting on the dilemma of evidence-based conservation management.

  20. Tango waves in a bidomain model of fertilization calcium waves

    Science.gov (United States)

    Li, Yue-Xian

    2003-12-01

    Fertilization of an egg cell is marked by one or several Ca 2+ waves that travel across the intra-cellular space, called fertilization Ca 2+ waves. Patterns of Ca 2+ waves observed in mature or immature oocytes include traveling fronts and pulses as well as concentric and spiral waves. These patterns have been studied in other excitable media in physical, chemical, and biological systems. Here, we report the discovery of a new wave phenomenon in the numerical study of a bidomain model of fertilization Ca 2+ waves. This wave is a front that propagates in a back-and-forth manner that resembles the movement of tango dancers, thus is called a tango wave. When the medium is excitable, a forward-moving tango wave can generate traveling pulses that propagate down the space without reversal. The study shows that the occurrence of tango waves is related to spatial inhomogeneity in the local dynamics. This is tested and confirmed by simulating similar waves in a medium with stationary spatial inhomogeneity. Similar waves are also obtained in a FitzHugh-Nagumo system with a linear spatial ramp. In both the bidomain model of Ca 2+ waves and the FitzHugh-Nagumo system, the front is stable when the slope of a linear ramp is large. As the slope decreases beyond a critical value, front oscillations occur. The study shows that tango waves facilitate the dispersion of localized Ca 2+. Key features of the bidomain model underlying the occurrence of tango waves are revealed. These features are commonly found in egg cells of a variety of species. Thus, we predict that tango waves can occur in real egg cells provided that a slowly varying inhomogeneity does occur following the sperm entry. The observation of tango wave-like waves in nemertean worm and ascidian eggs seems to support such a prediction.

  1. Tough adults, frail babies: an analysis of stress sensitivity across early life-history stages of widely introduced marine invertebrates.

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    M Carmen Pineda

    Full Text Available All ontogenetic stages of a life cycle are exposed to environmental conditions so that population persistence depends on the performance of both adults and offspring. Most studies analysing the influence of abiotic conditions on species performance have focussed on adults, while studies covering early life-history stages remain rare. We investigated the responses of early stages of two widely introduced ascidians, Styela plicata and Microcosmus squamiger, to different abiotic conditions. Stressors mimicked conditions in the habitats where both species can be found in their distributional ranges and responses were related to the selection potential of their populations by analysing their genetic diversity. Four developmental stages (egg fertilisation, larval development, settlement, metamorphosis were studied after exposure to high temperature (30°C, low salinities (26 and 22‰ and high copper concentrations (25, 50 and 100 µg/L. Although most stressors effectively led to failure of complete development (fertilisation through metamorphosis, fertilisation and larval development were the most sensitive stages. All the studied stressors affected the development of both species, though responses differed with stage and stressor. S. plicata was overall more resistant to copper, and some stages of M. squamiger to low salinities. No relationship was found between parental genetic composition and responses to stressors. We conclude that successful development can be prevented at several life-history stages, and therefore, it is essential to consider multiple stages when assessing species' abilities to tolerate stress. Moreover, we found that early development of these species cannot be completed under conditions prevailing where adults live. These populations must therefore recruit from elsewhere or reproduce during temporal windows of more benign conditions. Alternatively, novel strategies or behaviours that increase overall reproductive success

  2. Tough adults, frail babies: an analysis of stress sensitivity across early life-history stages of widely introduced marine invertebrates.

    Science.gov (United States)

    Pineda, M Carmen; McQuaid, Christopher D; Turon, Xavier; López-Legentil, Susanna; Ordóñez, Víctor; Rius, Marc

    2012-01-01

    All ontogenetic stages of a life cycle are exposed to environmental conditions so that population persistence depends on the performance of both adults and offspring. Most studies analysing the influence of abiotic conditions on species performance have focussed on adults, while studies covering early life-history stages remain rare. We investigated the responses of early stages of two widely introduced ascidians, Styela plicata and Microcosmus squamiger, to different abiotic conditions. Stressors mimicked conditions in the habitats where both species can be found in their distributional ranges and responses were related to the selection potential of their populations by analysing their genetic diversity. Four developmental stages (egg fertilisation, larval development, settlement, metamorphosis) were studied after exposure to high temperature (30°C), low salinities (26 and 22‰) and high copper concentrations (25, 50 and 100 µg/L). Although most stressors effectively led to failure of complete development (fertilisation through metamorphosis), fertilisation and larval development were the most sensitive stages. All the studied stressors affected the development of both species, though responses differed with stage and stressor. S. plicata was overall more resistant to copper, and some stages of M. squamiger to low salinities. No relationship was found between parental genetic composition and responses to stressors. We conclude that successful development can be prevented at several life-history stages, and therefore, it is essential to consider multiple stages when assessing species' abilities to tolerate stress. Moreover, we found that early development of these species cannot be completed under conditions prevailing where adults live. These populations must therefore recruit from elsewhere or reproduce during temporal windows of more benign conditions. Alternatively, novel strategies or behaviours that increase overall reproductive success might be

  3. COPI vesicle transport is a common requirement for tube expansion in Drosophila.

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    Satish Arcot Jayaram

    Full Text Available BACKGROUND: Tube expansion defects like stenoses and atresias cause devastating human diseases. Luminal expansion during organogenesis begins to be elucidated in several systems but we still lack a mechanistic view of the process in many organs. The Drosophila tracheal respiratory system provides an amenable model to study tube size regulation. In the trachea, COPII anterograde transport of luminal proteins is required for extracellular matrix assembly and the concurrent tube expansion. PRINCIPAL FINDINGS: We identified and analyzed Drosophila COPI retrograde transport mutants with narrow tracheal tubes. gammaCOP mutants fail to efficiently secrete luminal components and assemble the luminal chitinous matrix during tracheal tube expansion. Likewise, tube extension is defective in salivary glands, where it also coincides with a failure in the luminal deposition and assembly of a distinct, transient intraluminal matrix. Drosophila gammaCOP colocalizes with cis-Golgi markers and in gammaCOP mutant embryos the ER and Golgi structures are severely disrupted. Analysis of gammaCOP and Sar1 double mutants suggests that bidirectional ER-Golgi traffic maintains the ER and Golgi compartments and is required for secretion and assembly of luminal matrixes during tube expansion. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate the function of COPI components in organ morphogenesis and highlight the common role of apical secretion and assembly of transient organotypic matrices in tube expansion. Intraluminal matrices have been detected in the notochord of ascidians and zebrafish COPI mutants show defects in notochord expansion. Thus, the programmed deposition and growth of distinct luminal molds may provide distending forces during tube expansion in diverse organs.

  4. Regional connectivity and coastal expansion: differentiating pre-border and post-border vectors for the invasive tunicate Styela clava.

    Science.gov (United States)

    Goldstien, S J; Schiel, D R; Gemmell, N J

    2010-03-01

    The dramatic increase in marine bio-invasions, particularly of non-indigenous ascidians, has highlighted the vulnerability of marine ecosystems and the productive sectors that rely on them. A critical issue in managing invasive species is determining the relative roles of ongoing introductions, versus the local movement of propagules from established source populations. Styela clava (Herdman, 1882), the Asian clubbed tunicate, once restricted to the Pacific shores of Asia and Russia, is now abundant throughout the northern and southern hemispheres and has had significant economic impact in at least one site of incursion. In 2005 S. clava was identified in New Zealand. The recent introduction of this species, coupled with its restricted distribution, provided an ideal model to compare and contrast the introduction and expansion process. In this study, the mitochondrial DNA cytochrome oxidase subunit I gene (COI) gene and 11 microsatellite markers were used to test the regional genetic structure and diversity of 318 S. clava individuals from 10 populations within New Zealand. Both markers showed significant differentiation between the northern and southern populations, indicative of minimal pre- or post-border connectivity. Additional statistics further support pre- and post-border differentiation among Port and Harbour populations (i.e. marinas and aquaculture farms). We conclude that New Zealand receives multiple introductions, and that the primary vector for pre-border incursions and post-border spread is most likely the extensive influx of recreational vessels that enter northern marinas independent of the Port. This is a timely reminder of the potential for hull-fouling organisms to expand their range as climates change and open new pathways.

  5. Unusual symbiotic cyanobacteria association in the genetically diverse intertidal marine sponge Hymeniacidon perlevis (Demospongiae, Halichondrida.

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    Anoop Alex

    Full Text Available Cyanobacteria represent one of the most common members of the sponge-associated bacterial community and are abundant symbionts of coral reef ecosystems. In this study we used Transmission Electron Microscopy (TEM and molecular techniques (16S rRNA gene marker to characterize the spatial distribution of cyanobionts in the widely dispersed marine intertidal sponge Hymeniacidon perlevis along the coast of Portugal (Atlantic Ocean. We described new sponge associated cyanobacterial morphotypes (Xenococcus-like and we further observed Acaryochloris sp. as a sponge symbiont, previously only reported in association with ascidians. Besides these two unique cyanobacteria, H. perlevis predominantly harbored Synechococcus sp. and uncultured marine cyanobacteria. Our study supports the hypothesis that the community of sponge cyanobionts varies irrespective of the geographical location and is likely influenced by seasonal fluctuations. The observed multiple cyanobacterial association among sponges of the same host species over a large distance may be attributed to horizontal transfer of symbionts. This may explain the absence of a co-evolutionary pattern between the sponge host and its symbionts. Finally, in spite of the short geographic sampling distance covered, we observed an unexpected high intra-specific genetic diversity in H. perlevis using the mitochondrial genes ATP6 (π = 0.00177, COI (π = 0.00241 and intergenic spacer SP1 (π = 0.00277 relative to the levels of genetic variation of marine sponges elsewhere. Our study suggests that genotypic variation among the sponge host H. perlevis and the associated symbiotic cyanobacteria diversity may be larger than previously recognized.

  6. Predation limits spread of Didemnum vexillum into natural habitats from refuges on anthropogenic structures.

    Science.gov (United States)

    Forrest, Barrie M; Fletcher, Lauren M; Atalah, Javier; Piola, Richard F; Hopkins, Grant A

    2013-01-01

    Non-indigenous species can dominate fouling assemblages on artificial structures in marine environments; however, the extent to which infected structures act as reservoirs for subsequent spread to natural habitats is poorly understood. Didemnum vexillum is one of few colonial ascidian species that is widely reported to be highly invasive in natural ecosystems, but which in New Zealand proliferates only on suspended structures. Experimental work revealed that D. vexillum established equally well on suspended artificial and natural substrata, and was able to overgrow suspended settlement plates that were completely covered in other cosmopolitan fouling species. Fragmentation led to a level of D. vexillum cover that was significantly greater than was achieved as a result of ambient larval recruitment. The species failed to establish following fragment transplants onto seabed cobbles and into beds of macroalgae. The establishment success of D. vexillum was greatest in summer compared with autumn, and on the underside of experimental settlement plates that were suspended off the seabed to avoid benthic predators. Where benthic predation pressure was reduced by caging, D. vexillum establishment success was broadly comparable to suspended treatments; by contrast, the species did not establish on the face-up aspect of uncaged plates. This study provides compelling evidence that benthic predation was a key mechanism that prevented D. vexillum's establishment in the cobble habitats of the study region. The widespread occurrence of D. vexillum on suspended anthropogenic structures is consistent with evidence for other sessile invertebrates that such habitats provide a refuge from benthic predation. For invasive species generally, anthropogenic structures are likely to be most important as propagule reservoirs for spread to natural habitats in situations where predation and other mechanisms do not limit their subsequent proliferation.

  7. Predation limits spread of Didemnum vexillum into natural habitats from refuges on anthropogenic structures.

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    Barrie M Forrest

    Full Text Available Non-indigenous species can dominate fouling assemblages on artificial structures in marine environments; however, the extent to which infected structures act as reservoirs for subsequent spread to natural habitats is poorly understood. Didemnum vexillum is one of few colonial ascidian species that is widely reported to be highly invasive in natural ecosystems, but which in New Zealand proliferates only on suspended structures. Experimental work revealed that D. vexillum established equally well on suspended artificial and natural substrata, and was able to overgrow suspended settlement plates that were completely covered in other cosmopolitan fouling species. Fragmentation led to a level of D. vexillum cover that was significantly greater than was achieved as a result of ambient larval recruitment. The species failed to establish following fragment transplants onto seabed cobbles and into beds of macroalgae. The establishment success of D. vexillum was greatest in summer compared with autumn, and on the underside of experimental settlement plates that were suspended off the seabed to avoid benthic predators. Where benthic predation pressure was reduced by caging, D. vexillum establishment success was broadly comparable to suspended treatments; by contrast, the species did not establish on the face-up aspect of uncaged plates. This study provides compelling evidence that benthic predation was a key mechanism that prevented D. vexillum's establishment in the cobble habitats of the study region. The widespread occurrence of D. vexillum on suspended anthropogenic structures is consistent with evidence for other sessile invertebrates that such habitats provide a refuge from benthic predation. For invasive species generally, anthropogenic structures are likely to be most important as propagule reservoirs for spread to natural habitats in situations where predation and other mechanisms do not limit their subsequent proliferation.

  8. Role of Recruitment Processes in Structuring Coralligenous Benthic Assemblages in the Northern Adriatic Continental Shelf

    Science.gov (United States)

    Abbiati, Marco

    2016-01-01

    Coralligenous biogenic reefs are among the most diverse marine habitats in the Mediterranean Sea. The northern Adriatic mesophotic coralligenous outcrops host very rich and diverse epibenthic assemblages. Several studies quantified the low temporal variability and high spatial heterogeneity of these habitats, while processes driving structuring and differentiation are still poorly understood. To shed light on these processes, temporal and spatial patterns of colonisation were investigated using travertine tiles deployed on three coralligenous outcrops, corresponding to the main typologies of benthic assemblages described in previous studies. Three years after deployment, assemblages colonising travertine tiles resembled the differentiation among sites revealed by the natural assemblages in terms of major ecological groups. Processes structuring and maintaining species diversity have been explored. Pioneer species with high reproduction rate, long distance larval dispersal and fast growth (e.g. the serpulid polychaete Spirobranchus triqueter and the bivalve Anomia ephippium), were the most abundant in the early stages of recruitment on the two outcrops further away from the coast and with lower sedimentation. Their success may vary according to larval availability and environmental conditions (e.g., sedimentation rates). At these sites early-stage lasted 10–12 months, during which even species from natural substrates began colonising tiles by settlement of planktonic propagules (e.g., encrusting calcareous Rhodophyta) and lateral encroachment (e.g., sponges and ascidians). On coastal outcrop, exposed to a higher sedimentation rates, tiles were colonised by fast-growing algal turfs. Resilience of northern Adriatic coralligenous assemblages, and maintenance of their diversity, appeared largely entrusted to asexual reproduction. Exploring the mechanisms that underlie the formation and maintenance of the species diversity is crucial to improve our understanding of

  9. An efficient method to find potentially universal population genetic markers, applied to metazoans

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    Chenuil Anne

    2010-09-01

    Full Text Available Abstract Background Despite the impressive growth of sequence databases, the limited availability of nuclear markers that are sufficiently polymorphic for population genetics and phylogeography and applicable across various phyla restricts many potential studies, particularly in non-model organisms. Numerous introns have invariant positions among kingdoms, providing a potential source for such markers. Unfortunately, most of the few known EPIC (Exon Primed Intron Crossing loci are restricted to vertebrates or belong to multigenic families. Results In order to develop markers with broad applicability, we designed a bioinformatic approach aimed at avoiding multigenic families while identifying intron positions conserved across metazoan phyla. We developed a program facilitating the identification of EPIC loci which allowed slight variation in intron position. From the Homolens databases we selected 29 gene families which contained 52 promising introns for which we designed 93 primer pairs. PCR tests were performed on several ascidians, echinoderms, bivalves and cnidarians. On average, 24 different introns per genus were amplified in bilaterians. Remarkably, five of the introns successfully amplified in all of the metazoan genera tested (a dozen genera, including cnidarians. The influence of several factors on amplification success was investigated. Success rate was not related to the phylogenetic relatedness of a taxon to the groups that most influenced primer design, showing that these EPIC markers are extremely conserved in animals. Conclusions Our new method now makes it possible to (i rapidly isolate a set of EPIC markers for any phylum, even outside the animal kingdom, and thus, (ii compare genetic diversity at potentially homologous polymorphic loci between divergent taxa.

  10. A single and rapid calcium wave at egg activation in Drosophila

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    Anna H. York-Andersen

    2015-03-01

    Full Text Available Activation is an essential process that accompanies fertilisation in all animals and heralds major cellular changes, most notably, resumption of the cell cycle. While activation involves wave-like oscillations in intracellular Ca2+ concentration in mammals, ascidians and polychaete worms and a single Ca2+ peak in fish and frogs, in insects, such as Drosophila, to date, it has not been shown what changes in intracellular Ca2+ levels occur. Here, we utilise ratiometric imaging of Ca2+ indicator dyes and genetically encoded Ca2+ indicator proteins to identify and characterise a single, rapid, transient wave of Ca2+ in the Drosophila egg at activation. Using genetic tools, physical manipulation and pharmacological treatments we demonstrate that the propagation of the Ca2+ wave requires an intact actin cytoskeleton and an increase in intracellular Ca2+ can be uncoupled from egg swelling, but not from progression of the cell cycle. We further show that mechanical pressure alone is not sufficient to initiate a Ca2+ wave. We also find that processing bodies, sites of mRNA decay and translational regulation, become dispersed following the Ca2+ transient. Based on this data we propose the following model for egg activation in Drosophila: exposure to lateral oviduct fluid initiates an increase in intracellular Ca2+ at the egg posterior via osmotic swelling, possibly through mechano-sensitive Ca2+ channels; a single Ca2+ wave then propagates in an actin dependent manner; this Ca2+ wave co-ordinates key developmental events including resumption of the cell cycle and initiation of translation of mRNAs such as bicoid.

  11. Discovery and Evaluation of Thiazinoquinones as Anti-Protozoal Agents

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    Marcel Kaiser

    2013-09-01

    Full Text Available Pure compound screening has identified the dioxothiazino-quinoline-quinone ascidian metabolite ascidiathiazone A (2 to be a moderate growth inhibitor of Trypanosoma brucei rhodesiense (IC50 3.1 μM and Plasmodium falciparum (K1 dual drug resistant strain (IC50 3.3 μM while exhibiting low levels of cytotoxicity (L6, IC50 167 μM. A series of C-7 amide and Δ2(3 analogues were prepared that explored the influence of lipophilicity and oxidation state on observed anti-protozoal activity and selectivity. Little variation in anti-malarial potency was observed (IC50 0.62–6.5 μM, and no correlation was apparent between anti-malarial and anti-T. brucei activity. Phenethylamide 7e and Δ2(3-glycine analogue 8k exhibited similar anti-Pf activity to 2 but with slightly enhanced selectivity (SI 72 and 93, respectively, while Δ2(3-phenethylamide 8e (IC50 0.67 μM, SI 78 exhibited improved potency and selectivity towards T. brucei rhodesiense compared to the natural product hit. A second series of analogues were prepared that replaced the quinoline ring of 2 with benzofuran or benzothiophene moieties. While esters 10a/10b and 15 were once again found to exhibit cytotoxicity, carboxylic acid analogues exhibited potent anti-Pf activity (IC50 0.34–0.035 μM combined with excellent selectivity (SI 560–4000. In vivo evaluation of a furan carboxylic acid analogue against P. berghei was undertaken, demonstrating 85.7% and 47% reductions in parasitaemia with ip or oral dosing respectively.

  12. Evolution of neural crest and placodes: amphioxus as a model for the ancestral vertebrate?

    Science.gov (United States)

    Holland, L. Z.; Holland, N. D.

    2001-01-01

    Recent studies of protochordates (ascidian tunicates and amphioxus) have given insights into possible ancestors of 2 of the characteristic features of the vertebrate head: neural crest and placodes. The neural crest probably evolved from cells on either side of the neural plate-epidermis boundary in a protochordate ancestral to the vertebrates. In amphioxus, homologues of several vertebrate neural crest marker genes (BMP2/4, Pax3/7, Msx, Dll and Snail) are expressed at the edges of the neural plate and/or adjacent nonneural ectoderm. Some of these markers are also similarly expressed in tunicates. In protochordates, however, these cells, unlike vertebrate neural crest, neither migrate as individuals through embryonic tissues nor differentiate into a wide spectrum of cell types. Therefore, while the protochordate ancestor of the vertebrates probably had the beginnings of a genetic programme for neural crest formation, this programme was augmented in the earliest vertebrates to attain definitive neural crest. Clear homologues of vertebrate placodes are lacking in protochordates. However, both amphioxus and tunicates have ectodermal sensory cells. In tunicates these are all primary neurons, sending axons to the central nervous system, while in amphioxus, the ectodermal sensory cells include both primary neurons and secondary neurons lacking axons. Comparisons of developmental gene expression suggest that the anterior ectoderm in amphioxus may be homologous to the vertebrate olfactory placode, the only vertebrate placode with primary, not secondary, neurons. Similarly, biochemical, morphological and gene expression data suggest that amphioxus and tunicates also have homologues of the adenohypophysis, one of the few vertebrate structures derived from nonneurogenic placodes. In contrast, the origin of the other vertebrate placodes is very uncertain.

  13. Short-term post-mortality predation and scavenging and longer-term recovery after anoxia in the northern Adriatic Sea

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    M. Blasnig

    2013-03-01

    Full Text Available In the Mediterranean, the northern Adriatic Sea shows most features known to promote late-summer hypoxia and anoxia. These features, along with anthropogenic eutrophication and marine snow events, have led to repeated benthic mortalities here. The present study was designed to document the post-anoxia macrofauna dynamics. We deployed an underwater instrument to induce small-scale anoxia in situ (total area 0.5 m2. Two time-lapse camera deployments examined short-term scavenging of the moribund and dead organisms (multi-species clumps consisting of sponges and ascidians over a 3-day period (August 2008: 71.5 h, September 2008: 67.5 h. Longer-term recovery (2 yr in the same two plots was examined with an independent photo-series. Predators and scavengers arrived in a distinct sequence. The first to arrive were demersal (Gobius niger, Serranus hepatus and benthopelagic fishes (Diplodus vulgaris, Pagellus erythrinus, followed by hermit crabs (Paguristes eremita, showing a clear day/night rhythm in presence and gastropods (Hexaplex trunculus. This sequence of arrival is attributed to the relative speeds of the organisms and their densities. The scavengers remained in dense aggregations (e.g. up to 33 P. eremita individuals at one time as long as the dead organisms were available. The whole sessile fauna was largely removed or consumed within 7 (August plot and 13 (September plot days after anoxia. No macroepibenthic recovery took place in the experimental plots one and two years after anoxia. This study underlines the sensitivity of this soft-bottom community and supports calls for reducing additional anthropogenic disturbances such as damaging commercial fishing practices that impede recolonization and threaten benthic community structure and function over the long-term.

  14. Tolerance of sponge assemblages to temperature anomalies: resilience and proliferation of sponges following the 1997-8 El-Nino southern oscillation.

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    Francisco Kelmo

    Full Text Available Coral reefs across the world are under threat from a range of stressors, and while there has been considerable focus on the impacts of these stressors on corals, far less is known about their effect on other reef organisms. The 1997-8 El-Niño Southern Oscillation (ENSO had notable and severe impacts on coral reefs worldwide, but not all reef organisms were negatively impacted by this large-scale event. Here we describe how the sponge fauna at Bahia, Brazil was influenced by the 1997-8 ENSO event. Sponge assemblages from three contrasting reef habitats (reef tops, walls and shallow banks at four sites were assessed annually from 1995 to 2011. The within-habitat sponge diversity did not vary significantly across the study period; however, there was a significant increase in density in all habitats. Multivariate analyses revealed no significant difference in sponge assemblage composition (ANOSIM between pre- and post-ENSO years for any of the habitats, suggesting that neither the 1997-8 nor any subsequent smaller ENSO events have had any measurable impact on the reef sponge assemblage. Importantly, this is in marked contrast to the results previously reported for a suite of other taxa (including corals, echinoderms, bryozoans, and ascidians, which all suffered mass mortalities as a result of the ENSO event. Our results suggest that of all reef taxa, sponges have the potential to be resilient to large-scale thermal stress events and we hypothesize that sponges might be less affected by projected increases in sea surface temperature compared to other major groups of reef organisms.

  15. The substantial first impact of bottom fishing on rare biodiversity hotspots: a dilemma for evidence-based conservation.

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    Robert Cook

    Full Text Available This study describes the impact of the first passage of two types of bottom-towed fishing gear on rare protected shellfish-reefs formed by the horse mussel Modiolus modiolus (L.. One of the study sites was trawled and the other was scallop-dredged. Divers collected HD video imagery of epifauna from quadrats at the two study sites and directed infaunal samples from one site. The total number of epifaunal organisms was significantly reduced following a single pass of a trawl (90% or scallop dredge (59%, as was the diversity of the associated community and the total number of M. modiolus at the trawled site. At both sites declines in anthozoans, hydrozoans, bivalves, echinoderms and ascidians accounted for most of the change. A year later, no recovery was evident at the trawled site and significantly fewer infaunal taxa (polychaetes, malacostracans, bivalves and ophuroids were recorded in the trawl track. The severity of the two types of impact reflected the undisturbed status of the habitats compared to previous studies. As a 'priority habitat' the nature of the impacts described on M. modiolus communities are important to the development of conservation management policy and indicators of condition in Marine Protected Areas (EU Habitats Directive as well as indicators of 'Good Environmental Status' under the European Union Marine Strategy Framework Directive. Conservation managers are under pressure to support decisions with good quality evidence. Elsewhere, indirect studies have shown declines of M. modiolus biogenic communities in fishing grounds. However, given the protected status of the rare habitat, premeditated demonstration of direct impact is unethical or illegal in Marine Protected Areas. This study therefore provides a unique opportunity to investigate the impact from fishing gear whilst at the same time reflecting on the dilemma of evidence-based conservation management.

  16. Biofouling of inlet pipes affects water quality in running seawater aquaria and compromises sponge cell proliferation

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    Brittany E. Alexander

    2015-12-01

    Full Text Available Marine organism are often kept, cultured, and experimented on in running seawater aquaria. However, surprisingly little attention is given to the nutrient composition of the water flowing through these systems, which is generally assumed to equal in situ conditions, but may change due to the presence of biofouling organisms. Significantly lower bacterial abundances and higher inorganic nitrogen species (nitrate, nitrite, and ammonium were measured in aquarium water when biofouling organisms were present within a 7-year old inlet pipe feeding a tropical reef running seawater aquaria system, compared with aquarium water fed by a new, biofouling-free inlet pipe. These water quality changes are indicative of the feeding activity and waste production of the suspension- and filter-feeding communities found in the old pipe, which included sponges, bivalves, barnacles, and ascidians. To illustrate the physiological consequences of these water quality changes on a model organism kept in the aquaria system, we investigated the influence of the presence and absence of the biofouling community on the functioning of the filter-feeding sponge Halisarca caerulea, by determining its choanocyte (filter cell proliferation rates. We found a 34% increase in choanocyte proliferation rates following the replacement of the inlet pipe (i.e., removal of the biofouling community. This indicates that the physiological functioning of the sponge was compromised due to suboptimal food conditions within the aquarium resulting from the presence of the biofouling organisms in the inlet pipe. This study has implications for the husbandry and performance of experiments with marine organisms in running seawater aquaria systems. Inlet pipes should be checked regularly, and replaced if necessary, in order to avoid excessive biofouling and to approach in situ water quality.

  17. RNA-seq-based metatranscriptomic and microscopic investigation reveals novel metalloproteases of Neobodo sp. as potential virulence factors for soft tunic syndrome in Halocynthia roretzi.

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    Ho Bin Jang

    Full Text Available Bodonids and trypanosomatids are derived from a common ancestor with the bodonids being a more primitive lineage. The Neobodonida, one of the three clades of bodonids, can be free-living, commensal or parasitic. Despite the ecological and evolutionary significance of these organisms, however, many of their biological and pathological features are currently unknown. Here, we employed metatranscriptomics using RNA-seq technology combined with field-emission microscopy to reveal the virulence factors of a recently described genus of Neobodonida that is considered to be responsible for ascidian soft tunic syndrome (AsSTS, but whose pathogenesis is unclear. Our microscopic observation of infected tunic tissues suggested putative virulence factors, enabling us to extract novel candidate transcripts; these included cysteine proteases of the families C1 and C2, serine proteases of S51 and S9 families, and metalloproteases grouped into families M1, M3, M8, M14, M16, M17, M24, M41, and M49. Protease activity/inhibition assays and the estimation of expression levels within gene clusters allowed us to identify metalloprotease-like enzymes as potential virulence attributes for AsSTS. Furthermore, a multimarker-based phylogenetic analysis using 1,184 concatenated amino acid sequences clarified the order Neobodo sp. In sum, we herein used metatranscriptomics to elucidate the in situ expression profiles of uncharacterized putative transcripts of Neobodo sp., combined these results with microscopic observation to select candidate genes relevant to pathogenesis, and used empirical screening to define important virulence factors.

  18. Rubrolides as model for the development of new lactones and their aza analogs as potential photosynthesis inhibitors.

    Science.gov (United States)

    Pereira, Ulisses A; Barbosa, Luiz C A; Demuner, Antônio J; Silva, Antônio A; Bertazzini, Michele; Forlani, Giuseppe

    2015-07-01

    Natural phytotoxins and their synthetic analogs are a potential source of new bioactive compounds for agriculture. Analogs of rubrolides, a class of γ-alkylidene-γ-lactones isolated from different ascidians, have been shown to interfere with the photosynthetic electron-transport chain, yet their activity needs to be improved. With this aim, ten 5-aryl-6-benzyl-4-bromopyridazin-3(2H)-ones were prepared in yields ranging from 44 to 88% by reaction of their correspondent γ-alkylidene-γ-lactones with NH2 NH2 . The structures of these rubrolide analogs were determined by (1) H- and (13) C-NMR, 2D-NMR (COSY and HETCOR), NOE difference, and MS techniques. These compounds were evaluated for their abilities of interfering with the light-driven reduction of ferricyanide by isolated spinach chloroplasts. Lactones with electron-withdrawing substituents in the para-position of the benzylidene ring were the most effective inhibitors. Characterization of the activity of 11b/11b' suggested a mechanism based on the interaction with the plastoquinone binding site of photosystem II. Addition of several compounds to the culture medium of a cyanobacterial model strain was found to inhibit algal growth. However, the relative effectiveness was not consistent with their activity in vitro, suggesting the occurrence of multiple targets and/or detoxyfication mechanisms. Indeed, the compounds showed differential effects on the heterotrophic growth of some crop species, Cucumis sativus and Sorghum bicolor. Pyridazin-3(2H)-ones 12e, 12i, and 12j, which have been found poorly active against the photosynthetic electron transport, were the most effective in inhibiting the growth of some weeds, Ipomoea grandifolia and Brachiaria decumbens, under greenhouse conditions.

  19. Carbonate production and deposition in a warm-temperate macroalgal environment, Investigator Strait, South Australia

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    James, Noel P.; Bone, Yvonne

    2011-08-01

    The prolific macroalgal forests in shallow (red algae that are grazed by herbivorous gastropods, 2) an intermediate, 5-20 cm-high community of fleshy red algae, and 3) a 20-100 cm+-high canopy of large phaeophytes (especially Ecklonia, Cystophora and Xiophora) whose blades are locally encrusted with bryozoans, such as Membranipora membranacea, and spirorbids. Concealed surfaces of subvertical rock walls and cryptic habitats behind the macroalgal curtain have two tiers; 1) a cornucopia of encrusting plants and animals, especially crustose and geniculate corallines in shallow water, that give way in water depths > 4 m to numerous bryozoans (especially fenestrates), serpulid worms, numerous and diverse demosponges, ascidians, small solitary corals, epifaunal echinoids, and gastropods, and 2) a veil of macroalgae (mainly Cystophora and Ecklonia) that drapes down and shades the rock walls. Most carbonate sediment production does not come from calcareous epiphytes on the macroalgae but comes from the coralline algae and calcareous invertebrates living on the rock walls and in concealed depressions. Mollusks (gastropods and bivalves) and geniculate coralline algae with numerous lithoclasts, crustose coralline fragments, barnacle plates, serpulid worms, bryozoans, and large benthic foraminifers (especially Amphistegina) dominate the resultant gravels and sands; but there is little or no mud. This is because carbonate sediment is the result of production not only in the macrophyte factory but also in adjacent seagrass factories. Particles produced in the macroalgal factory are shed onto the adjacent seafloor, where they form the requisite sandy substrates for quick colonization by seagrasses. Thus, over time the sediment in this shallow but hydrodynaically energetic environment becomes a mixture of materials from the two sources with seagrasses contributing gastropods, large benthic foraminifers, spirorbids, bryozoans and articulated corallines to the sediment milieu. If

  20. New Mediterranean Biodiversity Records (October, 2014

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    S. KATSANEVAKIS

    2014-09-01

    Full Text Available The Collective Article ‘New Mediterranean Biodiversity Records’ of the Mediterranean Marine Science journal offers the means to publish biodiversity records in the Mediterranean Sea. The current article is divided in two parts, for records of alien and native species respectively. The new records of alien species include: the red alga Asparagopsis taxiformis (Crete and Lakonicos Gulf (Greece; the red alga Grateloupia turuturu (along the Israeli Mediterranean shore; the mantis shrimp Clorida albolitura (Gulf of Antalya, Turkey; the mud crab Dyspanopeus sayi (Mar Piccolo of Taranto, Ionian Sea; the blue crab Callinectes sapidus (Chios Island, Greece; the isopod Paracerceis sculpta (northern Aegean Sea, Greece; the sea urchin Diadema setosum (Gökova Bay, Turkey; the molluscs Smaragdia souverbiana, Murex forskoehlii, Fusinus verrucosus, Circenita callipyga, and Aplysia dactylomela (Syria; the cephalaspidean mollusc Haminoea cyanomarginata (Baia di Puolo, Massa Lubrense, Campania, southern Italy; the topmouth gudgeon Pseudorasbora parva (Civitavecchia, Tyrrhenian Sea; the fangtooth moray Enchelycore anatine (Plemmirio marine reserve, Sicily; the silver-cheeked toadfish Lagocephalus sceleratus (Saros Bay, Turkey; and Ibiza channel, Spain; the Indo-Pacific ascidian Herdmania momusin Kastelorizo Island (Greece; and the foraminiferal Clavulina multicam erata (Saronikos Gulf, Greece. The record of L. sceleratus in Spain consists the deepest (350-400m depth record of the species in the Mediterranean Sea. The new records of native species include: first record of the ctenophore Cestum veneris in Turkish marine waters; the presence of Holothuria tubulosa and Holothuria polii in the Bay of Igoumenitsa (Greece; the first recorded sighting of the bull ray Pteromylaeus bovinus in Maltese waters; and a new record of the fish Lobotes surinamensis from Maliakos Gulf. 

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

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    Christopher eSouthan

    2013-12-01

    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.

  2. Sediment Burial Intolerance of Marine Macroinvertebrates.

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    Vicki J Hendrick

    Full Text Available The marine environment contains suspended particulate matter which originates from natural and anthropogenic sources. Settlement of this material can leave benthic organisms susceptible to smothering, especially if burial is sudden i.e. following storms or activities such as dredging. Their survival will depend on their tolerance to, and their ability to escape from burial. Here we present data from a multi-factorial experiment measuring burial responses incorporating duration, sediment fraction and depth. Six macroinvertebrates commonly found in sediment rich environments were selected for their commercial and/or conservation importance. Assessments revealed that the brittle star (Ophiura ophiura, the queen scallop (Aequipecten opercularis and the sea squirt (Ciona intestinalis were all highly intolerant to burial whilst the green urchin (Psammichinus miliaris and the anemone (Sagartiogeton laceratus, showed intermediate and low intolerance respectively, to burial. The least intolerant, with very high survival was the Ross worm (Sabellaria spinulosa. With the exception of C. intestinalis, increasing duration and depth of burial with finer sediment fractions resulted in increased mortality for all species assessed. For C. intestinalis depth of burial and sediment fraction were found to be inconsequential since there was complete mortality of all specimens buried for more than one day. When burial emergence was assessed O. ophiura emerged most frequently, followed by P. miliaris. The former emerged most frequently from the medium and fine sediments whereas P. miliaris emerged more frequently from coarse sediment. Both A. opercularis and S. laceratus showed similar emergence responses over time, with A. opercularis emerging more frequently under coarse sediments. The frequency of emergence of S. laceratus increased with progressively finer sediment and C. intestinalis did not emerge from burial irrespective of sediment fraction or depth. Finally

  3. Localization of neuropeptide gene expression in larvae of an echinoderm, the starfish Asterias rubens

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    Tatiana D Mayorova

    2016-12-01

    Full Text Available Neuropeptides are an ancient class of neuronal signaling molecules that regulate a variety of physiological and behavioral processes in animals. The life cycle of many animals includes a larval stage(s that precedes metamorphic transition to a reproductively active adult stage but, with the exception of Drosophila melanogaster and other insects, research on neuropeptide signaling has hitherto largely focused on adult animals. However, recent advances in genome/transcriptome sequencing have facilitated investigation of neuropeptide expression/function in the larvae of protostomian (e.g. the annelid Platynereis dumerilii and deuterostomian (e.g. the urochordate Ciona intestinalis invertebrates. Accordingly, here we report the first multi-gene investigation of larval neuropeptide precursor expression in a species belonging to the phylum Echinodermata - the starfish Asterias rubens. Whole-mount mRNA in situ hybridization was used to visualize in bipinnaria and brachiolaria stage larvae the expression of eight neuropeptide precursors: L-type SALMFamide (S1, F-type SALMFamide (S2, vasopressin/oxytocin-type, NGFFYamide, thyrotropin-releasing hormone-type, gonadotropin-releasing hormone-type, calcitonin-type and corticotropin-releasing hormone-type. Expression of only three of the precursors (S1, S2, NGFFYamide was observed in bipinnaria larvae but by the brachiolaria stage expression of all eight precursors was detected. An evolutionarily conserved feature of larval nervous systems is the apical organ and in starfish larvae this comprises the bilaterally symmetrical lateral ganglia, but only the S1 and S2 precursors were found to be expressed in these ganglia. A prominent feature of brachiolaria larvae is the attachment complex, comprising the brachia and adhesive disk, which mediates larval attachment to a substratum prior to metamorphosis. Interestingly, all of the neuropeptide precursors examined here are expressed in the attachment complex, with

  4. A manual collection of Syt, Esyt, Rph3a, Rph3al, Doc2, and Dblc2 genes from 46 metazoan genomes - an open access resource for neuroscience and evolutionary biology

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    Craxton Molly

    2010-01-01

    Full Text Available Abstract Background Synaptotagmin proteins were first identified in nervous tissue, residing in synaptic vesicles. Synaptotagmins were subsequently found to form a large family, some members of which play important roles in calcium triggered exocytic events. These members have been investigated intensively, but other family members are not well understood, making it difficult to grasp the meaning of family membership in functional terms. Further difficulty arises as families are defined quite legitimately in different ways: by common descent or by common possession of distinguishing features. One definition does not necessarily imply the other. The evolutionary range of genome sequences now available, can shed more light on synaptotagmin gene phylogeny and clarify family relationships. The aim of compiling this open access collection of synaptotagmin and synaptotagmin-like sequences, is that its use may lead to greater understanding of the biological function of these proteins in an evolutionary context. Results 46 metazoan genomes were examined and their complement of Syt, Esyt, Rph3a, Rph3al, Doc2 and Dblc2 genes identified. All of the sequences were compared, named, then examined in detail. Esyt genes were formerly named Fam62. The species in this collection are Trichoplax, Nematostella, Capitella, Helobdella, Lottia, Ciona, Strongylocentrotus, Branchiostoma, Ixodes, Daphnia, Acyrthosiphon, Tribolium, Nasonia, Apis, Anopheles, Drosophila, Caenorhabditis, Takifugu, Tetraodon, Gasterosteus, Oryzias, Danio, Xenopus, Anolis, Gallus, Taeniopygia,Ornithorhynchus, Monodelphis, Mus and Homo. All of the data described in this paper is available as additional files. Conclusions Only a subset of synaptotagmin proteins appear able to function as calcium triggers. Syt1, Syt7 and Syt9 are ancient conserved synaptotagmins of this type. Some animals carry extensive repertoires of synaptotagmin genes. Other animals of no less complexity, carry only a small

  5. Cellulose Synthesis in Agrobacterium tumefaciens

    Energy Technology Data Exchange (ETDEWEB)

    Alan R. White; Ann G. Matthysse

    2004-07-31

    We have cloned the celC gene and its homologue from E. coli, yhjM, in an expression vector and expressed the both genes in E. coli; we have determined that the YhjM protein is able to complement in vitro cellulose synthesis by extracts of A. tumefaciens celC mutants, we have purified the YhjM protein product and are currently examining its enzymatic activity; we have examined whole cell extracts of CelC and various other cellulose mutants and wild type bacteria for the presence of cellulose oligomers and cellulose; we have examined the ability of extracts of wild type and cellulose mutants including CelC to incorporate UDP-14C-glucose into cellulose and into water-soluble, ethanol-insoluble oligosaccharides; we have made mutants which synthesize greater amounts of cellulose than the wild type; and we have examined the role of cellulose in the formation of biofilms by A. tumefaciens. In addition we have examined the ability of a putative cellulose synthase gene from the tunicate Ciona savignyi to complement an A. tumefaciens celA mutant. The greatest difference between our knowledge of bacterial cellulose synthesis when we started this project and current knowledge is that in 1999 when we wrote the original grant very few bacteria were known to synthesize cellulose and genes involved in this synthesis were sequenced only from Acetobacter species, A. tumefaciens and Rhizobium leguminosarum. Currently many bacteria are known to synthesize cellulose and genes that may be involved have been sequenced from more than 10 species of bacteria. This additional information has raised the possibility of attempting to use genes from one bacterium to complement mutants in another bacterium. This will enable us to examine the question of which genes are responsible for the three dimensional structure of cellulose (since this differs among bacterial species) and also to examine the interactions between the various proteins required for cellulose synthesis. We have carried out one

  6. Epitope of titin A-band-specific monoclonal antibody Tit1 5 H1.1 is highly conserved in several Fn3 domains of the titin molecule. Centriole staining in human, mouse and zebrafish cells

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    Mikelsaar Aavo-Valdur

    2012-09-01

    Full Text Available Abstract Background Previously we have reported on the development of a new mouse anti-titin monoclonal antibody, named MAb Titl 5 H1.1, using the synthetic peptide N-AVNKYGIGEPLESDSVVAK-C which corresponds to an amino acid sequence in the A-region of the titin molecule as immunogen. In the human skeletal muscles, MAb Titl 5 H1.1 reacts specifically with titin in the A-band of the sarcomere and in different non-muscle cell types with nucleus and cytoplasm, including centrioles. In this report we have studied the evolutionary aspects of the binding of MAb Tit1 5 H1.1 with its target antigen (titin. Results We have specified the epitope area of MAb Tit1 5 H1.1 by subpeptide mapping to the hexapeptide N-AVNKYG-C. According to protein databases this amino acid sequence is located in the COOH-terminus of several different Fn3 domains of the A-region of titin molecule in many organisms, such as human being, mouse, rabbit, zebrafish (Danio rerio, and even in sea squirt (Ciona intestinalis. Our immunohisto- and cytochemical studies with MAb Tit1 5 H1.1 in human, mouse and zebrafish tissues and cell cultures showed a striated staining pattern in muscle cells and also staining of centrioles, cytoplasm and nuclei in non-muscle cells. Conclusions The data confirm that titin can play, in addition to the known roles in striated muscle cells also an important role in non-muscle cells as a centriole associated protein. This phenomenon is highly conserved in the evolution and is related to Fn3 domains of the titin molecule. Using titin A-band-specific monoclonal antibody MAb Tit1 5 H1.1 it was possible to locate titin in the sarcomeres of skeletal muscle cells and in the centrioles, cytoplasm and nuclei of non-muscle cells in phylogenetically so distant organisms as Homo sapiens, Mus musculus and zebrafish (Danio rerio.

  7. Identification and correction of abnormal, incomplete and mispredicted proteins in public databases

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    Bányai László

    2008-08-01

    Full Text Available Abstract Background Despite significant improvements in computational annotation of genomes, sequences of abnormal, incomplete or incorrectly predicted genes and proteins remain abundant in public databases. Since the majority of incomplete, abnormal or mispredicted entries are not annotated as such, these errors seriously affect the reliability of these databases. Here we describe the MisPred approach that may provide an efficient means for the quality control of databases. The current version of the MisPred approach uses five distinct routines for identifying abnormal, incomplete or mispredicted entries based on the principle that a sequence is likely to be incorrect if some of its features conflict with our current knowledge about protein-coding genes and proteins: (i conflict between the predicted subcellular localization of proteins and the absence of the corresponding sequence signals; (ii presence of extracellular and cytoplasmic domains and the absence of transmembrane segments; (iii co-occurrence of extracellular and nuclear domains; (iv violation of domain integrity; (v chimeras encoded by two or more genes located on different chromosomes. Results Analyses of predicted EnsEMBL protein sequences of nine deuterostome (Homo sapiens, Mus musculus, Rattus norvegicus, Monodelphis domestica, Gallus gallus, Xenopus tropicalis, Fugu rubripes, Danio rerio and Ciona intestinalis and two protostome species (Caenorhabditis elegans and Drosophila melanogaster have revealed that the absence of expected signal peptides and violation of domain integrity account for the majority of mispredictions. Analyses of sequences predicted by NCBI's GNOMON annotation pipeline show that the rates of mispredictions are comparable to those of EnsEMBL. Interestingly, even the manually curated UniProtKB/Swiss-Prot dataset is contaminated with mispredicted or abnormal proteins, although to a much lesser extent than UniProtKB/TrEMBL or the EnsEMBL or GNOMON

  8. Etude comparative des conditions environnementales potentiellement limitantes dans l'etablissement d'une espece aquatique envahissante Clona intestinalis (Linnaeus, 1767) dans deux systemes de bassins versants a l'ile-du Prince-Edouard, Canada

    Science.gov (United States)

    Mclaughlin, Janelle

    rate, larval establishment and survival of juvenile tunicates. All these elements can potentially be key factors on limiting the establishment of a population of C. intestinalis in the Orwell Bay aquatic system. Keywords: Invasive species, watershed, biogeography, tunicate, Ciona intestinalis, universal soil loss equation, hydrodynamic modeling, correspondence analysis, turbidity, environmental tolerance.

  9. Synaptotagmin gene content of the sequenced genomes

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    Craxton Molly

    2004-07-01

    Full Text Available Abstract Background Synaptotagmins exist as a large gene family in mammals. There is much interest in the function of certain family members which act crucially in the regulated synaptic vesicle exocytosis required for efficient neurotransmission. Knowledge of the functions of other family members is relatively poor and the presence of Synaptotagmin genes in plants indicates a role for the family as a whole which is wider than neurotransmission. Identification of the Synaptotagmin genes within completely sequenced genomes can provide the entire Synaptotagmin gene complement of each sequenced organism. Defining the detailed structures of all the Synaptotagmin genes and their encoded products can provide a useful resource for functional studies and a deeper understanding of the evolution of the gene family. The current rapid increase in the number of sequenced genomes from different branches of the tree of life, together with the public deposition of evolutionarily diverse transcript sequences make such studies worthwhile. Results I have compiled a detailed list of the Synaptotagmin genes of Caenorhabditis, Anopheles, Drosophila, Ciona, Danio, Fugu, Mus, Homo, Arabidopsis and Oryza by examining genomic and transcript sequences from public sequence databases together with some transcript sequences obtained by cDNA library screening and RT-PCR. I have compared all of the genes and investigated the relationship between plant Synaptotagmins and their non-Synaptotagmin counterparts. Conclusions I have identified and compared 98 Synaptotagmin genes from 10 sequenced genomes. Detailed comparison of transcript sequences reveals abundant and complex variation in Synaptotagmin gene expression and indicates the presence of Synaptotagmin genes in all animals and land plants. Amino acid sequence comparisons indicate patterns of conservation and diversity in function. Phylogenetic analysis shows the origin of Synaptotagmins in multicellular eukaryotes and their

  10. FAM20: an evolutionarily conserved family of secreted proteins expressed in hematopoietic cells

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    Cobos Everardo

    2005-01-01

    Full Text Available Abstract Background Hematopoiesis is a complex developmental process controlled by a large number of factors that regulate stem cell renewal, lineage commitment and differentiation. Secreted proteins, including the hematopoietic growth factors, play critical roles in these processes and have important biological and clinical significance. We have employed representational difference analysis to identify genes that are differentially expressed during experimentally induced myeloid differentiation in the murine EML hematopoietic stem cell line. Results One identified clone encoded a previously unidentified protein of 541 amino acids that contains an amino terminal signal sequence but no other characterized domains. This protein is a member of family of related proteins that has been named family with sequence similarity 20 (FAM20 with three members (FAM20A, FAM20B and FAM20C in mammals. Evolutionary comparisons revealed the existence of a single FAM20 gene in the simple vertebrate Ciona intestinalis and the invertebrate worm Caenorhabditis elegans and two genes in two insect species, Drosophila melanogaster and Anopheles gambiae. Six FAM20 family members were identified in the genome of the pufferfish, Fugu rubripes and five members in the zebrafish, Danio rerio. The mouse Fam20a protein was ectopically expressed in a mammalian cell line and found to be a bona fide secreted protein and efficient secretion was dependent on the integrity of the signal sequence. Expression analysis revealed that the Fam20a gene was indeed differentially expressed during hematopoietic differentiation and that the other two family members (Fam20b and Fam20c were also expressed during hematcpoiesis but that their mRNA levels did not vary significantly. Likewise FAM20A was expressed in more limited set of human tissues than the other two family members. Conclusions The FAM20 family represents a new family of secreted proteins with potential functions in regulating

  11. Observations of recruitment and colonization by tunicates and associated invertebrates using giant one-meter2 recruitment plates at Woods Hole, Massachusetts

    Science.gov (United States)

    Valentine, Page C.; Carman, M.R.; Blackwood, Dann S.

    2016-01-01

    Large recruitment plates measuring 1 × 1 m were deployed over an 18-month period from September 2013 to March 2015 for the purpose of documenting recruitment and colonization processes of marine invertebrate species at Woods Hole, Massachusetts. Each side of two plates was subdivided into 16 subareas (25 × 25 cm), and an observational strategy was developed whereby, at approximately two-week intervals, a different subarea was cleaned. Using this approach, we were able to photographically document species recruitment and growth interactions. Water temperature records from the site show that steady warming and cooling between 3 and 20° C changed at a mean rate of 0.2 ° C d-1. However, temperature changes during the coolest and warmest parts of the temperature cycle were highly variable. In 2014, between the first and last occurrence of 0° C, temperatures were ≤0° C 15 percent of the time, but in 2015 temperatures were ≤0° C 93 percent of the time. In 2014, between the first and last occurrence of 21° C, temperatures were ≥21° C 88 percent of the time, and this warm period correlated with the disappearance of the hydroid Ectopleura crocea, the solitary tunicates Ascidiella aspersa and Ciona intestinalis, and the 2013 generation of Botrylloides violaceus. In Woods Hole, large plates provided enough space to accommodate both fast- and slow-colonizing species, resulting in the establishment of a diverse assemblage that was observed over a long time period. The most successful colonizing species had relatively long reproductive and recruitment periods, grew rapidly, repelled settlement onto their surfaces by larvae of any species, defended themselves against overgrowth by any species, overwintered, and lived a long time. Of the three dominant species observed in this study, the colonial tunicates Didemnum vexillum and Botrylloides violaceus had these qualities; the encrusting colonial bryozoan Schizoporella unicornis had all but one, it grew more slowly

  12. Comparative genomics of the syndecans defines an ancestral genomic context associated with matrilins in vertebrates

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    Adams Josephine C

    2006-04-01

    between tetrapods and fish. In vertebrates, each of the four family members are encoded from paralogous genomic regions in which members of the matrilin family are also syntenic between tetrapods and fish. This genomic organization appears to have been set up after the divergence of urochordates (Ciona and vertebrates. The syndecan-1 gene appears to have been lost relatively early in the fish lineage. These conclusions provide the basis for a new model of syndecan evolution in vertebrates and a new perspective for analyzing the roles of syndecans in cells and whole organisms.

  13. Localization of Neuropeptide Gene Expression in Larvae of an Echinoderm, the Starfish Asterias rubens

    Science.gov (United States)

    Mayorova, Tatiana D.; Tian, Shi; Cai, Weigang; Semmens, Dean C.; Odekunle, Esther A.; Zandawala, Meet; Badi, Yusef; Rowe, Matthew L.; Egertová, Michaela; Elphick, Maurice R.

    2016-01-01

    Neuropeptides are an ancient class of neuronal signaling molecules that regulate a variety of physiological and behavioral processes in animals. The life cycle of many animals includes a larval stage(s) that precedes metamorphic transition to a reproductively active adult stage but, with the exception of Drosophila melanogaster and other insects, research on neuropeptide signaling has hitherto largely focused on adult animals. However, recent advances in genome/transcriptome sequencing have facilitated investigation of neuropeptide expression/function in the larvae of protostomian (e.g., the annelid Platynereis dumerilii) and deuterostomian (e.g., the urochordate Ciona intestinalis) invertebrates. Accordingly, here we report the first multi-gene investigation of larval neuropeptide precursor expression in a species belonging to the phylum Echinodermata—the starfish Asterias rubens. Whole-mount mRNA in situ hybridization was used to visualize in bipinnaria and brachiolaria stage larvae the expression of eight neuropeptide precursors: L-type SALMFamide (S1), F-type SALMFamide (S2), vasopressin/oxytocin-type, NGFFYamide, thyrotropin-releasing hormone-type, gonadotropin-releasing hormone-type, calcitonin-type and corticotropin-releasing hormone-type. Expression of only three of the precursors (S1, S2, NGFFYamide) was observed in bipinnaria larvae but by the brachiolaria stage expression of all eight precursors was detected. An evolutionarily conserved feature of larval nervous systems is the apical organ and in starfish larvae this comprises the bilaterally symmetrical lateral ganglia, but only the S1 and S2 precursors were found to be expressed in these ganglia. A prominent feature of brachiolaria larvae is the attachment complex, comprising the brachia and adhesive disk, which mediates larval attachment to a substratum prior to metamorphosis. Interestingly, all of the neuropeptide precursors examined here are expressed in the attachment complex, with distinctive

  14. Antimicrobial (including antimollicutes, antioxidant and anticholinesterase activities of Brazilian and Spanish marine organisms – evaluation of extracts and pure compounds

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    Éverson Miguel Bianco

    2015-12-01

    Full Text Available Abstract This work describes the antimicrobial, antioxidant and anticholinesterase activities in vitro of organic extracts from fourteen seaweeds, eleven sponges, two ascidians, one bryozoan, and one sea anemone species collected along the Brazilian and Spanish coast, as well as the isolation of the diterpene (4R, 9S, 14S-4α-acetoxy-9β,14α-dihydroxydolast-1(15,7-diene (1 and halogenated sesquiterpene elatol (2. The most promising antimicrobial results for cell wall bacteria were obtained by extracts from seaweeds Laurencia dendroidea and Sargassum vulgare var. nanun (MIC 250 μg/ml, and by the bryozoan Bugula neritina (MIC 62.5 μg/ml, both against Staphylococcus aureus. As for antimollicutes, extracts from seaweeds showed results better than the extracts from invertebrates. Almost all seaweeds assayed (92% exhibited some antimicrobial activity against mollicutes strains (Mycoplasma hominis,Mycoplasma genitalium,Mycoplasma capricolum and Mycoplasma pneumoniae strain FH. From these seaweeds, A1 (Canistrocarpus cervicornis, A11 (Gracilaria sp. and A4 (Lobophora variegata showed the best results for M. pneumoniae strain FH (MIC 250 μg/ml. Furthermore, compounds 1 and 2 were also assayed against mollicutes strains M. hominis,M. genitalium,M. capricolum,M. pneumoniae strain 129 and M. pneumoniae strain FH, which showed MIC > 100 μg/ml. Antioxidant activities of extracts from these marine organisms were inactive, except for E7 (from sponge Ircinia sp., which exhibited moderated antioxidant activities for two methods assayed (IC50 83.0 ± 0.1 μg/ml, and 52.0 ± 0.8 mg AA/g, respectively. Finally, for the anticholinesterase activity, all the 29 samples evaluated (100% exhibited some level of activity, with IC50 < 1000 μg/ml. From these, seaweeds extracts were considered more promising than marine invertebrate extracts [A10 (IC50 14.4 ± 0.1 μg/ml, A16 (IC50 16.4 ± 0.4 μg/ml and A8 (IC50 14.9 ± 0.5 μg/ml]. The findings of this work are useful

  15. Hemichordates and the Origin of Chordates

    Science.gov (United States)

    Gerhart, John; Kirschner, Marc; Lowe, Chris

    2002-01-01

    At the start of the period of the NASA grant three years ago, we had no information on the organization and development of the body axis of the hemichordate, Saccoglossus kowalevskii. Now we have substantial findings about the anteroposterior axis and dorsoventral axis, and based on this information, we have new insights about the origin of chordates from ancestral deuterostomes. We found ways to obtain and preserve large numbers of embryos and hatched juveniles. We can now collect about 40,000 embryos in the month of September, the time of S. kowalevskii spawning at Woods Hole. Excellent cDNA libraries were prepared from three developmental stages. From these libraries, we directly isolated about 30 gene ortholog sequences by screening and pcr techniques, all of these sequences of interest in the inquiry about the animal's organization and development. We also performed a mid-sized EST project (60,000 randomly picked clones, many of these arrayed). About half of these have been analyzed so far by blastx and are suitable for direct use of clones. We have obtained about 50 interesting sequences from this set. The rest still await analysis. Thus, at this time we have isolated orthologs of 80 genes that are known to be expressed in chordates in conserved domains and known to have interesting roles in chordate organization and development. The orthology of the S. kowalevskii sequences has been verified by neighbor joining and parsimony methods, with bootstrap estimates of validity. The S. kowalevskii sequences cluster with other deuterostome sequences, namely, other hemichordates, echinoderms, ascidians, amphioxus, or vertebrates, depending on what sequences are available in the database for comparison. We have used these sequences to do high quality in situ hybridization on S. kowalevskii embryos, and the results can be divided into three sections-those concerning the anteroposterior axis of S. kowalevskii in comparison to the same axis of chordates, those concerning

  16. Sperm proteasomes degrade sperm receptor on the egg zona pellucida during mammalian fertilization.

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    Shawn W Zimmerman

    Full Text Available Despite decades of research, the mechanism by which the fertilizing spermatozoon penetrates the mammalian vitelline membrane, the zona pellucida (ZP remains one of the unexplained fundamental events of human/mammalian development. Evidence has been accumulating in support of the 26S proteasome as a candidate for echinoderm, ascidian and mammalian egg coat lysin. Monitoring ZP protein degradation by sperm during fertilization is nearly impossible because those few spermatozoa that penetrate the ZP leave behind a virtually untraceable residue of degraded proteins. We have overcome this hurdle by designing an experimentally consistent in vitro system in which live boar spermatozoa are co-incubated with ZP-proteins (ZPP solubilized from porcine oocytes. Using this assay, mimicking sperm-egg interactions, we demonstrate that the sperm-borne proteasomes can degrade the sperm receptor protein ZPC. Upon coincubation with motile spermatozoa, the solubilized ZPP, which appear to be ubiquitinated, adhered to sperm acrosomal caps and induced acrosomal exocytosis/formation of the acrosomal shroud. The degradation of the sperm receptor protein ZPC was assessed by Western blotting band-densitometry and proteomics. A nearly identical pattern of sperm receptor degradation, evident already within the first 5 min of coincubation, was observed when the spermatozoa were replaced with the isolated, enzymatically active, sperm-derived proteasomes. ZPC degradation was blocked by proteasomal inhibitors and accelerated by ubiquitin-aldehyde(UBAL, a modified ubiquitin protein that stimulates proteasomal proteolysis. Such a degradation pattern of ZPC is consistent with in vitro fertilization studies, in which proteasomal inhibitors completely blocked fertilization, and UBAL increased fertilization and polyspermy rates. Preincubation of intact zona-enclosed ova with isolated active sperm proteasomes caused digestion, abrasions and loosening of the exposed zonae, and

  17. Impacts of trawling on benthic macro-fauna and -flora of the Spencer Gulf prawn fishing grounds

    Science.gov (United States)

    Svane, Ib; Hammett, Zoe; Lauer, Peter

    2009-05-01

    The overall effects of trawling on benthic habitats and their assemblages are dependent on the distribution and intensity of trawl effort. The benthic habitats of the Spencer Gulf prawn trawling grounds are subjected to known variable levels of trawling disturbance recorded from fisher's logbooks. These habitats have not been quantitatively investigated. The aim of the study was firstly to characterise the macro-faunal and -floral assemblages and secondly, to comparatively assess trawl impact by testing the null hypothesis of no differences between five sites exposed to different intensity of trawl effort. The distribution and abundance of benthic macro-fauna and -flora were studied at two sampling resolutions by using beam trawl sampling (˜10,000 m 2) and underwater stereophotography (˜4.5 m 2) at five sites with different levels of trawl disturbance (effort). The results showed that the Spencer Gulf prawn trawling grounds are characterised by sandy sediments with a low content of silt and clay, with the exception of one site with very fine gravel. Biomass, abundance and cover of macro-fauna and -flora were generally low throughout, but with large differences among sites. Biomass, abundance and cover were found to be negatively correlated to both trawl hours from 1994-1998 and during the period of study. ANOSIM and SIMPER analyses using biomass, abundance and percentage cover as variables showed significant differences between sites with eight species or taxonomic groups contributing more than 10% to the observed similarity within sites. The two northern sites were dominated by sponges and the bearded mussel, Trichomya hirsutus, and the southern hammer oyster, Malleus meridianus. Other species that contributed to the similarity within sites were the ascidian, Polycarpa viridis, mobile epifauna (the blue swimmer crab, Portunus pelagicus, and the western king prawn, Penaeus (Melicertus) latisulcatus) and demersal fish species (Degens leatherjacket, Thamnaconus

  18. Differential responses of emergent intertidal coral reef fauna to a large-scale El-Niño southern oscillation event: sponge and coral resilience.

    Science.gov (United States)

    Kelmo, Francisco; Bell, James J; Moraes, Simone Souza; Gomes, Rilza da Costa Tourinho; Mariano-Neto, Eduardo; Attrill, Martin J

    2014-01-01

    There is a paucity of information on the impacts of the 1997-8 El Niño event and subsequent climatic episodes on emergent intertidal coral reef assemblages. Given the environmental variability intertidal reefs experience, such reefs may potentially be more resilient to climatic events and provide important insights into the adaptation of reef fauna to future ocean warming. Here we report the results of a 17-year (1995-2011) biodiversity survey of four emergent coral reef ecosystems in Bahia, Brazil, to assess the impact of a major El Niño event on the reef fauna, and determine any subsequent recovery. The densities of two species of coral, Favia gravida and Siderastrea stellata, did not vary significantly across the survey period, indicating a high degree of tolerance to the El Niño associated stress. However, there were marked decreases in the diversity of other taxa. Molluscs, bryozoans and ascidians suffered severe declines in diversity and abundance and had not recovered to pre-El Niño levels by the end of the study. Echinoderms were reduced to a single species in 1999, Echinometra lucunter, although diversity levels had recovered by 2002. Sponge assemblages were not impacted by the 1997-8 event and their densities had increased by the study end. Multivariate analysis indicated that a stable invertebrate community had re-established on the reefs after the El Niño event, but it has a different overall composition to the pre-El Niño community. It is unclear if community recovery will continue given more time, but our study highlights that any increase in the frequency of large-scale climatic events to more than one a decade is likely to result in a persistent lower-diversity state. Our results also suggest some coral and sponge species are particularly resilient to the El Niño-associated stress and therefore represent suitable models to investigate temperature adaptation in reef organisms.

  19. Sperm proteasomes degrade sperm receptor on the egg zona pellucida during mammalian fertilization.

    Science.gov (United States)

    Zimmerman, Shawn W; Manandhar, Gaurishankar; Yi, Young-Joo; Gupta, Satish K; Sutovsky, Miriam; Odhiambo, John F; Powell, Michael D; Miller, David J; Sutovsky, Peter

    2011-02-23

    Despite decades of research, the mechanism by which the fertilizing spermatozoon penetrates the mammalian vitelline membrane, the zona pellucida (ZP) remains one of the unexplained fundamental events of human/mammalian development. Evidence has been accumulating in support of the 26S proteasome as a candidate for echinoderm, ascidian and mammalian egg coat lysin. Monitoring ZP protein degradation by sperm during fertilization is nearly impossible because those few spermatozoa that penetrate the ZP leave behind a virtually untraceable residue of degraded proteins. We have overcome this hurdle by designing an experimentally consistent in vitro system in which live boar spermatozoa are co-incubated with ZP-proteins (ZPP) solubilized from porcine oocytes. Using this assay, mimicking sperm-egg interactions, we demonstrate that the sperm-borne proteasomes can degrade the sperm receptor protein ZPC. Upon coincubation with motile spermatozoa, the solubilized ZPP, which appear to be ubiquitinated, adhered to sperm acrosomal caps and induced acrosomal exocytosis/formation of the acrosomal shroud. The degradation of the sperm receptor protein ZPC was assessed by Western blotting band-densitometry and proteomics. A nearly identical pattern of sperm receptor degradation, evident already within the first 5 min of coincubation, was observed when the spermatozoa were replaced with the isolated, enzymatically active, sperm-derived proteasomes. ZPC degradation was blocked by proteasomal inhibitors and accelerated by ubiquitin-aldehyde(UBAL), a modified ubiquitin protein that stimulates proteasomal proteolysis. Such a degradation pattern of ZPC is consistent with in vitro fertilization studies, in which proteasomal inhibitors completely blocked fertilization, and UBAL increased fertilization and polyspermy rates. Preincubation of intact zona-enclosed ova with isolated active sperm proteasomes caused digestion, abrasions and loosening of the exposed zonae, and significantly reduced

  20. Evolution of the interaction between Runx2 and VDR, two transcription factors involved in osteoblastogenesis

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    Barriga Elias H

    2010-03-01

    , using pull-down experiments between recombinant proteins, we show that the VDR homologue from teleosts, but not from ascidians, is able to directly interact with the mammalian Runx2 homologue. Conclusions We propose an evolutionary scenario for the assembly of the molecular machinery involving Runx2 and VDR in vertebrates. In the last common ancestor of actinopterygians and sacropterygians, the three Runx paralogues possessed the potential to physically and functionally interact with the VDR protein. Therefore, 1α,25-dihydroxyvitamin D3 might have been able to modulate the transcriptional activity of Runx1, Runx2 or Runx3 in the tissues expressing VDR. After the split from amphibians, in the lineage leading to amniotes, Runx2 and VDR became robustly co-expressed in developing skeletal elements, and their regulatory interaction was incorporated in the genetic program involved in the specification and differentiation of osteoblasts.

  1. A review of contemporary patterns of endemism for shallow water reef fauna in the Red Sea

    KAUST Repository

    DiBattista, Joseph

    2015-11-03

    Aim The Red Sea is characterised by a unique fauna and historical periods of desiccation, hypersalinity and intermittent isolation. The origin and contemporary composition of reef-associated taxa in this region can illuminate biogeographical principles about vicariance and the establishment (or local extirpation) of existing species. Here we aim to: (1) outline the distribution of shallow water fauna between the Red Sea and adjacent regions, (2) explore mechanisms for maintaining these distributions and (3) propose hypotheses to test these mechanisms. Location Red Sea, Gulf of Aden, Arabian Sea, Arabian Gulf and Indian Ocean. Methods Updated checklists for scleractinian corals, fishes and non-coral invertebrates were used to determine species richness in the Red Sea and the rest of the Arabian Peninsula and assess levels of endemism. Fine-scale diversity and abundance of reef fishes within the Red Sea were explored using ecological survey data. Results Within the Red Sea, we recorded 346 zooxanthellate and azooxanthellate scleractinian coral species of which 19 are endemic (5.5%). Currently 635 species of polychaetes, 211 echinoderms and 79 ascidians have been documented, with endemism rates of 12.6%, 8.1% and 16.5% respectively. A preliminary compilation of 231 species of crustaceans and 137 species of molluscs include 10.0% and 6.6% endemism respectively. We documented 1071 shallow fish species, with 12.9% endemic in the entire Red Sea and 14.1% endemic in the Red Sea and Gulf of Aden. Based on ecological survey data of endemic fishes, there were no major changes in species richness or abundance across 1100 km of Saudi Arabian coastline. Main conclusions The Red Sea biota appears resilient to major environmental fluctuations and is characterized by high rates of endemism with variable degrees of incursion into the Gulf of Aden. The nearby Omani and Arabian Gulfs also have variable environments and high levels of endemism, but these are not consistently distinct

  2. Zoogeografia storica e attuale dei carnivori e degli ungulati italiani

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    Marco Masseti

    2003-10-01

    futuro a preservare inalterate le caratteristiche genetiche dei taxa "nativi" del territorio italiano. A parte alcuni casi di ampliamento spontaneo degli areali di distribuzione, anche le attuali composizioni a carnivori mostrano spesso le evidenze di un'alterazione preoccupante dei quadri biogeografici originari. L'eredità della ridefinizione globale degli equilibri ecologici originari italiani, condotta dall'uomo a partire dalle epoche preistoriche e continuata in quelle storiche senza apparente soluzione di continuità, suscita problemi di conservazione e di gestione non indifferenti. Fra di essi, deve essere tenuta in particolare conto la constatazione del fatto che, nella maggior parte dei casi, è impossibile ricostruire gli ecosistemi naturali del passato, poiché questi sono andati definitivamente distrutti e perduti da millenni. Riguardo, poi, alla vulnerabilità degli ecosistemi è anche piuttosto difficile riuscire a scongiurare in forma preventiva il rischio di nuove, future introduzioni. Va infine notato che in più di un caso le definizioni tassonomiche di cui disponiamo sono state basate su caratteri spesso inconsistenti e variabili, suscitando ancora oggi perplessità sulla validità sistematica di certi taxa, soprattutto se considerati a livello subspecifico. Carnivori Canis aureus (L., 1758 Canis lupus L., 1758 Vulpes vulpes (L., 1758 Nyctereutes procyonoides (Gray, 1834 Ursus arctos (L., 1758 Procion lotor (L., 1758 Mustela erminea L., 1758 Mustela nivalis L., 1766 Mustela putorius L., 1758 Mustela vison Schreber, 1777 Martes foina (Erxleben, 1777 Martes martes (L., 1758 Meles meles (L., 1758 Lutra lutra (L., 1758 Genetta genetta (L., 1758 Herpestes edwardsii (E. Geoffroy, 1818 Felis silvestris Schreber, 1775 Lynx lynx (L., 1758 Artiodattili Sus scrofa

  3. Mercado global y ciudadanía civil. La recuperación del horizonte de la emancipación humana en la filosofía política de Franz Hinkelammert

    Directory of Open Access Journals (Sweden)

    Estela Fernández Nadal

    2004-01-01

    Full Text Available A par tir del aná li sis crí ti co de las obras fun da men ta les de Hin ke lam mert, pro cu ra mos sis te ma ti zar su pen sa mien to éti co y po lí ti co en tor no de la opo si ción “mer ca do glo bal/ciu da da - nía ci vil”. Des ta ca mos el es fuer zo por res ca tar las po ten cia li da des li ber ta rias de la ca te go ría de ciu da da nía sin des co no cer sus lí mi tes ideo ló gi - cos y prác ti cos. Por una par te, está cla ro que la apa ri ción del “ciu da da no” es el re sul ta do his tó ri - co de las re vo lu cio nes bur gue sas y el pro duc to de una ope ra ción de ho mo lo ga ción que pone en tre pa rén te sis las de si gual da des rea les, sin su pri mir - las. Pero por otro, la “ciu da da nía” en cie rra una pa ra do ja con al can ces eman ci pa to rios, pues re - mi te a la fun da ción del es pa cio pú bli co, que se le - gi ti ma como an te rior a las de man das e in te re ses pri va dos. A par tir de allí, nues tro fi ló so fo con - clu ye la ne ce si dad de in te grar la crí ti ca mar xis ta a la ley del va lor como re gu la do ra de las re la cio - nes so cia les y a la igual dad con trac tual como pro duc to ra de dis cri mi na cio nes al in te rior de la so cie dad bur gue sa, con el ho ri zon te de la ciu da - da nía ci vil que pro ce de de la tra di ción del ra ciona lismoliberal. Sinembargo Hin ke lam mert no se con ten ta con pos tu lar una síntesis en tre dos tradiciones diferentes; por el contrario, propone una reflexión inquietante, completamente discordante en el contexto actual de la filosofía política y ajena a la preocupación por legitimar la democracia como forma de organización política acotada en el ejercicio de procedimientos de representación y delegación, y ciega ante las interpelaciones del sujeto real.

  4. A Microscopic Capacitor Model of Voltage Coupling in Membrane Proteins: Gating Charge Fluctuations in Ci-VSD.

    Science.gov (United States)

    Kim, Ilsoo; Warshel, Arieh

    2016-01-28

    The voltage sensitivity of membrane proteins is reflected in the response of the voltage sensing domains (VSDs) to the changes in membrane potential. This response is implicated in the displacement of positively charged residues, associated with the conformational changes of VSDs. The displaced charges generate nonlinear (i.e., voltage-dependent) capacitance current called the gating current (and its corresponding gating charge), which is a key experimental quantity that characterizes voltage activation in VSMP. However, the relevant theoretical/computational approaches, aimed to correlate the structural information on VSMP to electrophysiological measurements, have been rather limited, posing a broad challenge in computer simulations of VSMP. Concomitant with the development of our coarse-graining (CG) model of voltage coupling, we apply our theoretical framework for the treatments of voltage effects in membrane proteins to modeling the VSMP activation, taking the VSDs (Ci-VSD) derived from the Ciona intestinalis voltage sensitive phosphatase (Ci-VSP) as a model system. Our CG model reproduces the observed gating charge of Ci-VSD activation in several different perspectives. In particular, a new closed-form expression of the gating charge is evaluated in both nonequilibrium and equilibrium ways, while considering the fluctuation-dissipation relation that connects a nonequilibrium measurement of the gating charge to an equilibrium measurement of charge fluctuations (i.e., the voltage-independent linear component of membrane capacitance). In turn, the expression uncovers a novel link that connects an equilibrium measurement of the voltage-independent linear capacitance to a nonequilibrium measurement of the voltage-dependent nonlinear capacitance (whose integral over voltage is equal to the gating charge). In addition, our CG model yields capacitor-like voltage dependent free energy parabolas, resulting in the free energy difference and the free energy barrier for

  5. Causes and consequences of hypoxia on the Western Black Sea Shelf

    Science.gov (United States)

    Friedrich, Jana; Gomoiu, Marian-Trajan; Naeher, Sebastian; Secrieru, Dan; Teaca, Adrian

    2013-04-01

    opportunistic species such as worms. Following the economic collapse of eastern European countries during the 1990s, riverine nutrient loads decreased and the ecosystem is showing signs of slow recovery, such as a decrease in the frequency and duration of hypoxic events. However, nutrient fluxes from the sediments did not decrease significantly (Friedrich et al. 2010). We observe slight recovery of the macrobenthic community structure in terms of species numbers in the Romanian pre-Danubian sector. Opportunistic species, e.g., ascidians, worms and fast growing filamentous algae are currently filling ecologic niches left by the past ecosystem collapse. References Friedrich, J., Cociasu, A., & Mee, L. D. (2010). Historical legacy of Danube River nutrient discharge and eutrophication in the North-Western Black Sea - Nutrient recycling in the shelf sediments. Danube News, 12(22), 7-9. Friedrich J., Dinkel C., Friedl G., Pimenov N., Wijsman J., Gomoiu M.T., Cociasu A., Popa L. & Wehrli B. (2002). Benthic Nutrient Cycling and Diagenetic Pathways in the North-western Black Sea. Estuarine, Coastal and Shelf Science, 54, 369-383. Jones G.A. & Gagnon A.R. (1994). Radiocarbon chronology of Black Sea sediments. Deep Sea Research Part I: Oceanographic Research Papers, 41, 531-557. Mee L.D., Friedrich J. & Gomoiu M.-T. (2005). Restoring the Black Sea in times of uncertainty. Oceanography, 18, 32-43. Oguz, T. and Gilbert, D. (2007). Abrupt transitions of the top-down controlled Black Sea pelagic ecosystem during 1960-2000: Evidence for regime-shifts under strong fishery exploitation and nutrient enrichment modulated by climate-induced variations. Deep-Sea Research I: doi:10.1016/j.dsr.200609.200010.

  6. Variabilidad genética y estructura poblacional del tunicado Pyura chilensis Molina, 1782, en la costa de Chile Genetic variability and population structure in tunicate Pyura chilensis Molina, 1782, in the coast of Chile

    Directory of Open Access Journals (Sweden)

    MARCELA P ASTORGA

    2006-12-01

    Full Text Available El tunicado Pyura chilensis se ha considerado una especie de importancia ecológica, por concentrar una gran diversidad biológica en sus agregaciones y de importancia económica por ser un recurso de extracción por pescadores artesanales. Sin embargo, se han detectado cambios en la distribución y abundancia de sus poblaciones adjudicados a su sobreexplotación. Para llegar a establecer medidas de conservación de un recurso, es necesario entre otras cosas, conocer su variabilidad genética y su estructura poblacional, estimando los patrones y sus causas. Por lo tanto, en el presente trabajo se determinó el grado de variabilidad genética aloenzimática del piure P. chilensis y su estructura poblacional en base a tres localidades (Antofagasta, Talcahuano y Puerto Montt en la costa chilena. Los loci polimórficos obtenidos fueron Mdh-1 y Pgi-1. Los valores de Fst mostraron leve estructuración poblacional entre localidades (Fst 0,019 al igual que la prueba exacta de diferenciación genética (P = 0,031. Se observó diferenciación para la localidad de Puerto Montt en relación a las otras dos localidades en algunos de los dos loci. Los niveles de variabilidad observados en esta especie corresponden a lo esperados para otras ascidias. La estructuración genética poblacional puede ser explicada por una combinación de diferentes factores, entre los que destacan: (i el tiempo del periodo larval de 12 a 24 h, lo cual no facilitaría una amplia dispersión a lo largo de 2.500 km de costa y (ii las condiciones oceanográficas diferenciales entre localidades, junto a patrones de circulación cerrados que podrían llegar a restringir el flujo génico. Por último, proponemos que un conocimiento adecuado del grado de variabilidad, estructura y dinámica genética de las poblaciones son aspectos esenciales para tomar medidas de conservación de recursos explotados, tanto en ambientes abiertos como en áreas de manejoThe ascidian Pyura chilensis is an

  7. 刺参苗期附着基更换频率对刺参生长及其养殖系统菌群结构的影响%Effects of substrate change frequency on growth and variation of the microflora structure in a seedling cultivation system of sea cucumber Apostichopus japonicus

    Institute of Scientific and Technical Information of China (English)

    王印庚; 张文泽; 廖梅杰; 李彬; 荣小军; 张正; 李华; 范瑞用; 宁鲁光

    2016-01-01

    V. alginolyticus was the dominant bacteria.V. alginolyticus is an etiological pathogen for A. japonicus; therefore, it might have a close relationship with the occurrence of skin ul-cerative syndrome in the CF50group. Harmful animals, such asCiona intestinalis,Grantia nipponica, andHydroides ezoensis, compete for living space and food, causing slow growth of sea cucumbers. These animals emerged when the substrates had not been changed for a long time. The above results indicated that the optimal substrate change was once every 20 d in summer (July to September). Taking the production cost in consideration, it was suggested that the sub-strate should normally be changed once between 20 d and 30 d. These results will help to optimize breeding processes and health management for sea cucumbers.