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Sample records for mediterranean ascidian ciona

  1. Delineating metamorphic pathways in the ascidian Ciona intestinalis.

    PubMed

    Nakayama-Ishimura, Akie; Chambon, Jean-phillippe; Horie, Takeo; Satoh, Nori; Sasakura, Yasunori

    2009-02-15

    In most ascidians, metamorphosis of tadpole-like swimming larvae is accompanied by dynamic changes in their shape to form sessile adults. The mechanisms underlying ascidian metamorphosis have been debated for a long time. Although recent molecular studies have revealed the presence of various molecules involving in this process, the basic mechanism of the metamorphic events is still unclear. For example, it has not been solved whether all metamorphic events are organized by the same single pathway or by multiple, independent pathways. In the present study, we approached this question using the ascidian Ciona intestinalis. When the papillae and preoral lobes of the larvae were cut off, the papillae-cut larvae initiated certain trunk metamorphic events such as the formation of an ampulla, body axis rotation and adult organ growth without other metamorphic events. This observation indicates that metamorphic events can be divided into at least two groups, events initiated in the papillae-cut larva and events not initiated in this larva. In addition to this observation, we have isolated a novel mutant, tail regression failed (trf), which shows similar phenotypes to those of papillae-cut larvae. The phenotypes of trf mutants are basically different from those of swimming juvenile mutants (Sasakura, Y., Nakashima, K., Awazu, S., Matsuoka, T., Nakayama, A., Azuma, J., Satoh, N., 2005. Transposon-mediated insertional mutagenesis revealed the functions of animal cellulose synthase in the ascidian Ciona intestinalis. Proc. Natl. Acad. Sci. U. S. A. 102, 15134-15139.), which also show abnormal metamorphosis. These findings suggest a model by which ascidian metamorphic events can be classified into four groups initiated by different pathways.

  2. SL RNA genes of the ascidian tunicates Ciona intestinalis and Ciona savignyi.

    PubMed

    Yeats, Brendan; Matsumoto, Jun; Mortimer, Sandra I; Shoguchi, Eiichi; Satoh, Nori; Hastings, Kenneth E M

    2010-02-01

    We characterized by bioinformatics the trans-spliced leader donor RNA (SL RNA) genes of two ascidians, Ciona intestinalis and Ciona savignyi. The Ciona intestinalis genome contains approximately 670 copies of the SL RNA gene, principally on a 264-bp tandemly repeated element. Fluorescent in-situ hybridization mapped most of the repeats to a single site on the short arm of chromosome 8. The Ciona intestinalis genome also contains approximately 100 copies of a >3.6-kb element that carries 1) an SL RNA-related sequence (possible a pseudogene) and 2) genes for the U6 snRNA and a histone-like protein. The Ciona savignyi genome contains two SL RNA gene classes having the same SL sequence as Ciona intestinalis but differing in the intron-like segments. These reside in similar but distinct repeat units of 575 bp ( approximately 410 copies) and 552 bp ( approximately 250 copies) that are arranged as separate tandem repeats. In neither Ciona species is the 5S RNA gene present within the SL RNA gene repeat unit. Although the number of SL RNA genes is similar, there is little sequence similarity between the intestinalis and savignyi repeat units, apart from the region encoding the SL RNA itself. This suggests that cis-regulatory elements involved in transcription and 3'-end processing are likely to be present within the transcribed region. The genomes of both Ciona species also include > 100 dispersed short elements containing the 16-nt SL sequence and up to 6 additional nucleotides of the SL RNA sequence.

  3. Primary genetic linkage maps of the ascidian, Ciona intestinalis.

    PubMed

    Kano, Shungo; Satoh, Nori; Sordino, Paolo

    2006-01-01

    For whole-genome analysis in a basal chordate (protochordate), we used F1 pseudo-testcross mapping strategy and amplified fragment length polymorphism (AFLP) markers to construct primary linkage maps of the ascidian tunicate Ciona intestinalis. Two genetic maps consisted of 14 linkage groups, in agreement with the haploid chromosome number, and contained 276 and 125 AFLP loci derived from crosses between British and Neapolitan individuals. The two maps covered 4218.9 and 2086.9 cM, respectively, with an average marker interval of 16.1 and 18.9 cM. We observed a high recombinant ratio, ranging from 25 to 49 kb/cM, which can explain the high degree of polymorphism in this species. Some AFLP markers were converted to sequence tagged sites (STSs) by sequence determination, in order to create anchor markers for the fragmental physical map. Our recombination tools provide basic knowledge of genetic status and whole genome organization, and genetic markers to assist positional cloning in C. intestinalis.

  4. Germ cell mutations of the ascidian Ciona intestinalis with TALE nucleases.

    PubMed

    Yoshida, Keita; Treen, Nicholas; Hozumi, Akiko; Sakuma, Tetsushi; Yamamoto, Takashi; Sasakura, Yasunori

    2014-05-01

    Targeted mutagenesis of genes-of-interest, or gene-knockout, is a powerful method to address the functions of genes. Engineered nucleases have enabled this approach in various organisms because of their ease of use. The ascidian Ciona intestinalis is an excellent organism to analyze gene functions by means of genetic technologies. In our previous study, we reported mutagenesis of Ciona somatic cells with TALE nucleases (TALENs) by electroporating expression constructs. In this study, we report germ cell mutagenesis of Ciona by microinjecting mRNAs encoding TALENs. TALEN mRNAs introduced mutations to target genes in both somatic and germ cells. TALEN-mediated mutations in the germ cell genome were inherited by the next generation. We conclude that knockout lines of Ciona that have disrupted target genes can be established through TALEN-mediated germ cell mutagenesis.

  5. CRISPR/Cas9-mediated gene knockout in the ascidian Ciona intestinalis.

    PubMed

    Sasaki, Haruka; Yoshida, Keita; Hozumi, Akiko; Sasakura, Yasunori

    2014-09-01

    Knockout of genes with CRISPR/Cas9 is a newly emerged approach to investigate functions of genes in various organisms. We demonstrate that CRISPR/Cas9 can mutate endogenous genes of the ascidian Ciona intestinalis, a splendid model for elucidating molecular mechanisms for constructing the chordate body plan. Short guide RNA (sgRNA) and Cas9 mRNA, when they are expressed in Ciona embryos by means of microinjection or electroporation of their expression vectors, introduced mutations in the target genes. The specificity of target choice by sgRNA is relatively high compared to the reports from some other organisms, and a single nucleotide mutation at the sgRNA dramatically reduced mutation efficiency at the on-target site. CRISPR/Cas9-mediated mutagenesis will be a powerful method to study gene functions in Ciona along with another genome editing approach using TALE nucleases.

  6. Transposon-mediated targeted and specific knockdown of maternally expressed transcripts in the ascidian Ciona intestinalis.

    PubMed

    Iitsuka, Takako; Mita, Kaoru; Hozumi, Akiko; Hamada, Mayuko; Satoh, Nori; Sasakura, Yasunori

    2014-05-23

    Maternal mRNAs play crucial roles during early embryogenesis of ascidians, but their functions are largely unknown. In this study, we developed a new method to specifically knockdown maternal mRNAs in Ciona intestinalis using transposon-mediated transgenesis. We found that GFP expression is epigenetically silenced in Ciona intestinalis oocytes and eggs, and this epigenetic silencing of GFP was used to develop the knockdown method. When the 5' upstream promoter and 5' untranslated region (UTR) of a maternal gene are used to drive GFP in eggs, the maternal gene is specifically knocked down together with GFP. The 5' UTR of the maternal gene is the major element that determines the target gene silencing. Zygotic transcription of the target gene is unaffected, suggesting that the observed phenotypes specifically reflect the maternal function of the gene. This new method can provide breakthroughs in studying the functions of maternal mRNAs.

  7. Time course for tail regression during metamorphosis of the ascidian Ciona intestinalis.

    PubMed

    Matsunobu, Shohei; Sasakura, Yasunori

    2015-09-01

    In most ascidians, the tadpole-like swimming larvae dramatically change their body-plans during metamorphosis and develop into sessile adults. The mechanisms of ascidian metamorphosis have been researched and debated for many years. Until now information on the detailed time course of the initiation and completion of each metamorphic event has not been described. One dramatic and important event in ascidian metamorphosis is tail regression, in which ascidian larvae lose their tails to adjust themselves to sessile life. In the present study, we measured the time associated with tail regression in the ascidian Ciona intestinalis. Larvae are thought to acquire competency for each metamorphic event in certain developmental periods. We show that the timing with which the competence for tail regression is acquired is determined by the time since hatching, and this timing is not affected by the timing of post-hatching events such as adhesion. Because larvae need to adhere to substrates with their papillae to induce tail regression, we measured the duration for which larvae need to remain adhered in order to initiate tail regression and the time needed for the tail to regress. Larvae acquire the ability to adhere to substrates before they acquire tail regression competence. We found that when larvae adhered before they acquired tail regression competence, they were able to remember the experience of adhesion until they acquired the ability to undergo tail regression. The time course of the events associated with tail regression provides a valuable reference, upon which the cellular and molecular mechanisms of ascidian metamorphosis can be elucidated.

  8. Transcriptome dynamics in early embryos of the ascidian, Ciona intestinalis.

    PubMed

    Matsuoka, Terumi; Ikeda, Tatsuro; Fujimaki, Kotaro; Satou, Yutaka

    2013-12-15

    Maternally provided mRNAs and proteins direct early development and activate the zygotic genome. Using microarrays, we examined the dynamics of transcriptomes during the early development of a basal chordate, Ciona intestinalis. Microarray analysis of unfertilized eggs, as well as 8-, and 16- and 32-cell embryos revealed that nearly half of the genes encoded in the genome were expressed maternally, and that approximately only one-fourth of these genes were expressed at similar levels among eggs obtained from different individuals. Genes encoding proteins involved in protein phosphorylation were enriched in this latter group. More than 90% of maternal RNAs were not reduced before the 16-cell stage when the zygotic developmental program begins. Additionally we obtained gene expression profiles of individual blastomeres from the 8- and 16-cell embryos. On the basis of these profiles, we concluded that the posterior-most localization, which has been reported for over 20 different transcripts, is the only major localization pattern of maternal transcripts. Our data also showed that maternal factors establish only nine distinct patterns of zygotic gene expression at the 16-cell stage. Therefore, one of the main developmental functions of maternally supplied information is to establish these nine distinct expression patterns in the 16-cell embryo. The dynamics of transcriptomes in early-stage embryos provides a foundation for studying how maternal information starts the zygotic program.

  9. Siphon regeneration capacity is compromised during aging in the ascidian Ciona intestinalis.

    PubMed

    Jeffery, William R

    2012-01-01

    The ascidian Ciona intestinalis has a short life span and powerful regeneration capacities. The regeneration of the oral siphon (OS) involves wound healing, blastema formation, cell proliferation, and replacement of 8 oral pigment organs (OPO), the latter via differentiation and migration of stem/precursor cells from localized niches in the siphon. The restoration of OPO pattern during OS regeneration occurs with a high degree of accuracy through three successive cycles of amputation. It is shown here that oral siphons of the largest and oldest members of a wild Ciona population do not completely regenerate their siphons after amputation. The loss of regeneration capacity was accompanied by reduced cell proliferation. In contrast to arrested OS outgrowth, the stem/precursor cells responsible for OPO replacement "over-differentiate" after OS amputation in the oldest animals, the typical number of OPO is increased from 8 to 12-16, and malformed OPO are produced. Also in contrast to younger animals, the oldest animals of the population show arrested OPO development after two consecutive cycles of amputation and regeneration. We conclude that there is a size and age threshold in Ciona after which the regenerative capacity of the OS is compromised due to effects of aging on cell proliferation.

  10. Establishment of enhancer detection lines expressing GFP in the gut of the ascidian Ciona intestinalis.

    PubMed

    Yoshida, Reiko; Sasakura, Yasunori

    2012-01-01

    The gut is a tubular, endodermal organ for digesting food and absorbing nutrients. In this study, we characterized eight enhancer detection lines that express green fluorescent protein (GFP) in the whole or part of the digestive tube of the ascidian Ciona intestinalis. Three enhancer detection lines for the pyloric gland, a structure associated with the digestive tube, were also analyzed. These lines are valuable markers for analyzing the mechanisms of development of the gut. Based on the GFP expression of the enhancer detection lines together with morphological characteristics, the digestive tube of Ciona can be subdivided into at least 10 compartments in which different genetic cascades operate. Causal insertion sites of the enhancer detection lines were identified, and the expression pattern of the genes near the insertion sites were characterized by means of whole-mount in situ hybridization. We have characterized four and two genes that were specifically or strongly expressed in the digestive tube and pyloric gland, respectively. The present data provide the basic information and useful resources for studying gut formation in Ciona.

  11. Siphon Regeneration Capacity is Compromised During Aging in the Ascidian Ciona intestinalis

    PubMed Central

    Jeffery, William R.

    2012-01-01

    The ascidian Ciona intestinalis has a short life span and powerful regeneration capacities. The regeneration of the oral siphon (OS) involves wound healing, blastema formation, cell proliferation, and replacement of eight oral pigment organs (OPO), the latter via differentiation and migration of stem/precursor cells from localized siphon niches in the siphon. The restoration of OPO pattern during OS regeneration occurs with a high degree of accuracy through three successive cycles of amputation. It is shown here that oral siphons of the largest and oldest members of a wild Ciona population do not completely regenerate their siphons after amputation. The loss of regeneration capacity was accompanied by reduced cell proliferation. In contrast to arrested OS outgrowth, the stem/precursor cells responsible for OPO replacement “over-differentiate” after OS amputation in the oldest animals, the typical number of OPO is increased from eight to twelve-sixteen, and malformed OPO are produced. Also in contrast to younger animals, the oldest animals of the population show arrested OPO development after two consecutive cycles of amputation and regeneration. We conclude that there is a size and age threshold in Ciona after which the regenerative capacity of the OS is compromised due to effects of aging on cell proliferation. PMID:22935550

  12. Spermiotoxicity of nickel nanoparticles in the marine invertebrate Ciona intestinalis (ascidians)

    PubMed Central

    Gallo, Alessandra; Boni, Raffaele; Buttino, Isabella; Tosti, Elisabetta

    2016-01-01

    Abstract Nickel nanoparticles (Ni NPs) are increasingly used in modern industries as catalysts, sensors, and in electronic applications. Due to this large use, their inputs into marine environment have significantly increased; however, the potential ecotoxicological effects in marine environment have so far received little attention. In particular, little is known on the impact of NPs on gamete quality of marine organisms and on the consequences on fertility potential. The present study examines, for the first time, the impact of Ni NPs exposure on sperm quality of the marine invertebrate Ciona intestinalis (ascidian). Several parameters related with sperm status such as plasma membrane lipid peroxidation, mitochondrial membrane potential (MMP), intracellular pH, DNA integrity, and fertilizing ability were assessed as toxicity end points after exposure to different Ni NPs concentrations. Ni NPs generate oxidative stress that in turn induces lipid peroxidation and DNA fragmentation, and alters MMP and sperm morphology. Furthermore, sperm exposure to Ni NPs affects their fertilizing ability and causes developmental anomalies in the offspring. All together, these results reveal a spermiotoxicity of Ni NPs in ascidians suggesting that the application of these NPs should be carefully assessed as to their potential toxic effects on the health of marine organisms that, in turn, may influence the ecological system. This study shows that ascidian sperm represent a suitable and sensitive tool for the investigation of the toxicity of NPs entered into marine environment, for defining the mechanisms of toxic action and for the environmental monitoring purpose. PMID:27080039

  13. Inducible galectins are expressed in the inflamed pharynx of the ascidian Ciona intestinalis.

    PubMed

    Vizzini, Aiti; Parrinello, Daniela; Sanfratello, Maria Antonietta; Salerno, Giuseppina; Cammarata, Matteo; Parrinello, Nicolò

    2012-01-01

    Although ascidians belong to a key group in chordate phylogenesis, amino acid sequences of Ciona intestinalis galectin-CRDs (CiLgals-a and -b) have been retained too divergent from vertebrate galectins. In the present paper, to contribute in disclosing Bi-CRD galectin evolution a novel attempt was carried out on CiLgals-a and -b CRDs phylogenetic analysis, and their involvement in ascidian inflammatory responses was shown. CiLgals resulted aligned with Bi-CRD galectins from vertebrates (Xenopus tropicalis, Gallus gallus, Mus musculus, Homo sapiens), cephalochordates (Branchiostoma floridae), echinoderms (Strongylocentrotus purpuratus) and a mono-CRD galectin from the ascidian Clavelina picta. The CiLgals-a N-terminal and C-terminal CRDs contain the signature sequence involved in carbohydrate binding, whereas the CiLgals-b C-CRD presents only three out of seven key aminoacids and it could not be suitable as sugar binding motif. Sequence similarity between clusters suggests an evolutionary model based on CRD domain gene duplication and sequence diversification. In particular CiLgals-b N-CRD and C-CRD were similar to each other and both grouped with the ascidian C. picta mono-CRD. Homology modeling process shows a CiLgals molecular structure superimposed to chicken and mouse galectins. The CiLgals-a and CiLgals-b genes were upregulated by LPS inoculation suggesting that they are inducible and expressed in the inflamed pharynx as revealed by real-time PCR analysis. Finally, in situ hybridization and immunohistochemical assays showed their localization in the inflamed tissues, while immunoblotting analysis indicated that CiLgals can form oligomers.

  14. Proteomics of ionomycin-induced ascidian sperm reaction: Released and exposed sperm proteins in the ascidian Ciona intestinalis.

    PubMed

    Nakazawa, Shiori; Shirae-Kurabayashi, Maki; Otsuka, Kei; Sawada, Hitoshi

    2015-12-01

    Sperm proteins mediating sperm-egg interaction should be exhibited on the sperm surface, or exposed or released when sperm approach an egg. In ascidians (protochordates), sperm undergo a sperm reaction, characterized by enhanced sperm motility and mitochondrial swelling and shedding on contact with the vitelline coat (VC) or by treatment with Ca(2+) ionophore. Here, proteomic analysis was conducted on sperm exudates and sperm surface proteins using ionomycin-induced sperm reaction and cell-impermeable labeling in Ciona intestinalis type A (C. robusta). In the exudate from sperm treated with ionomycin, membrane proteins including a possible VC receptor CiUrabin were abundant, indicating the release of membranous compartments during sperm reaction. Among the surface proteins XP_009859314.1 (uncharacterized protein exhibiting homology to HrTTSP-1) was most abundant before the sperm reaction, but XP_004227079.1 (unknown Ig superfamily protein) appears to be most abundantly exposed by the sperm reaction. Moreover, proteins containing a notable set of domains, astacin-like metalloprotease domain and thrombospondin type 1 repeat(s), were found in this fraction. Possible roles in fertilization as well as localizations and behaviors of these proteins are discussed.

  15. Regeneration of oral siphon pigment organs in the ascidian Ciona intestinalis

    PubMed Central

    Auger, Hélène; Sasakura, Yasunori; Joly, Jean-Stéphane; Jeffery, William R.

    2013-01-01

    Ascidians have powerful capacities for regeneration but the underlying mechanisms are poorly understood. Here we examine oral siphon regeneration in the solitary ascidian Ciona intestinalis. Following amputation, the oral siphon rapidly reforms oral pigment organs (OPO) at its distal margin prior to slower regeneration of proximal siphon parts. The early stages of oral siphon reformation include cell proliferation and re-growth of the siphon nerves, although the neural complex (adult brain and associated organs) is not required for regeneration. Young animals reform OPO more rapidly after amputation than old animals indicating that regeneration is age dependent. UV irradiation, microcautery, and cultured siphon explant experiments indicate that OPOs are replaced as independent units based on local differentiation of progenitor cells within the siphon, rather than by cell migration from a distant source in the body. The typical pattern of eight OPOs and siphon lobes is restored with fidelity after distal amputation of the oral siphon, but as many as 16 OPOs and lobes can be reformed following proximal amputation near the siphon base. Thus, the pattern of OPO regeneration is determined by cues positioned along the proximal distal axis of the oral siphon. A model is presented in which columns of siphon tissue along the proximal–distal axis below pre-existing OPO are responsible for reproducing the normal OPO pattern during regeneration. This study reveals previously unknown principles of oral siphon and OPO regeneration that will be important for developing Ciona as a regeneration model in urochordates, which may be the closest living relatives of vertebrates. PMID:20059994

  16. Adverse effect of antifouling compounds on the reproductive mechanisms of the ascidian Ciona intestinalis.

    PubMed

    Gallo, Alessandra; Tosti, Elisabetta

    2013-09-20

    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.

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

    PubMed Central

    Gallo, Alessandra; Tosti, Elisabetta

    2013-01-01

    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. PMID:24065165

  18. Closing the wounds: one hundred and twenty five years of regenerative biology in the ascidian Ciona intestinalis.

    PubMed

    Jeffery, William R

    2015-01-01

    This year marks the 125th anniversary of the beginning of regeneration research in the ascidian Ciona intestinalis. A brief note was published in 1891, reporting the regeneration of the Ciona neural complex and siphons. This launched an active period of Ciona regeneration research culminating in the demonstration of partial body regeneration: the ability of proximal body parts to regenerate distal ones, but not vice versa. In a process resembling regeneration, wounds in the siphon tube were discovered to result in the formation of an ectopic siphon. Ciona regeneration research then lapsed into a period of relative inactivity after the purported demonstration of the inheritance of acquired characters using siphon regeneration as a model. Around the turn of the present century, Ciona regeneration research experienced a new blossoming. The current studies established the morphological and physiological integrity of the regeneration process and its resemblance to ontogeny. They also determined some of the cell types responsible for tissue and organ replacement and their sources in the body. Finally, they showed that regenerative capacity is reduced with age. Many other aspects of regeneration now can be studied at the mechanistic level because of the extensive molecular tools available in Ciona.

  19. Filter-feeding ascidians ( Ciona intestinalis) in a shallow cove: Implications of hydrodynamics for grazing impact

    NASA Astrophysics Data System (ADS)

    Riisgård, Hans Ulrik; Jürgensen, Carsten; Clausen, Torben

    1996-06-01

    The grazing impact by a dense population of filter-feeding ascidians Ciona intestinalis on horizontally flowing water (driven by density circulation) in a shallow cove (Kertinge Nor, Denmark) has been described and quantified by means of a simple one-dimensional numerical model. The agreement between observations and modelled predictions was satisfactory. The applied numerical model has the following analytical solution in the idealized case: Cx = C0e -( fx/ Y2) , where Cx = algal concentration at a downstream distance x, C0 = initial concentration, f = F/ vc; F = area specific population filtration rate; vc = current velocity; Y 2 = depth of mixed layer below halocline. The numerical model quantifies the actual grazing impact while the analytical model illustrates the governing physics in well-known terms. To describe situations with no current ( i.e. stagnant water), we performed simulation studies in the laboratory and measured vertical profiles of algal cells over filter-feeding C. intestinalis. The results showed that phytoplankton became reduced in a near-bottom water layer of 20-30 cm thickness. Such water layers may develop in stagnant water (calm days and no advective currents), thus uncoupling the pelagic food and the filter feeders which within a short time will experience extremely meagre food conditions.

  20. A one-dimensional model of PCP signaling: polarized cell behavior in the notochord of the ascidian Ciona

    PubMed Central

    Kourakis, Matthew J.; Reeves, Wendy; Newman-Smith, Erin; Maury, Benoit; Abdul-Wajid, Sarah; Smith, William C.

    2014-01-01

    Despite its importance in development and physiology the planar cell polarity (PCP) pathway remains one of the most enigmatic signaling mechanisms. The notochord of the ascidian Ciona provides a unique model for investigating the PCP pathway. Interestingly, the notochord appears to be the only embryonic structure in Ciona activating the PCP pathway. Moreover, the Ciona notochord as a single-file array of forty polarized cells is a uniquely tractable system for the study of polarization dynamics and the transmission of the PCP pathway. Here, we test models for propagation of a polarizing signal, interrogating temporal, spatial and signaling requirements. A simple cell-cell relay cascading through the entire length of the notochord is not supported; instead a more complex mechanism is revealed, with interactions influencing polarity between neighboring cells, but not distant ones. Mechanisms coordinating notochord-wide polarity remain elusive, but appear to entrain general (i.e., global) polarity even while local interactions remain important. However, this global polarizer does not appear to act as a localized, spatially-restricted determinant. Coordination of polarity along the long axis of the notochord requires the PCP pathway, a role we demonstrate is temporally distinct from this pathway’s earlier role in convergent extension and intercalation. We also reveal polarity in the notochord to be dynamic: a cell’s polarity state can be changed and then restored, underscoring the Ciona notochord’s amenability for in vivo studies of PCP. PMID:25173874

  1. Metamorphosis of the invasive ascidian Ciona savignyi: environmental variables and chemical exposure.

    PubMed

    Cahill, Patrick L; Atalah, Javier; Selwood, Andrew I; Kuhajek, Jeanne M

    2016-01-01

    In this study, the effects of environmental variables on larval metamorphosis of the solitary ascidian Ciona savignyi were investigated in a laboratory setting. The progression of metamorphic changes were tracked under various temperature, photoperiod, substrate, larval density, and vessel size regimes. Metamorphosis was maximised at 18 °C, 12:12 h subdued light:dark, smooth polystyrene substrate, and 10 larvae mL(-1) in a twelve-well tissue culture plate. Eliminating the air-water interface by filling culture vessels to capacity further increased the proportion of metamorphosed larvae; 87 ± 5% of larvae completed metamorphosis within 5 days compared to 45 ± 5% in control wells. The effects of the reference antifouling compounds polygodial, portimine, oroidin, chlorothalonil, and tolylfluanid on C. savignyi were subsequently determined, highlighting (1) the sensitivity of C. savignyi metamorphosis to chemical exposure and (2) the potential to use C. savignyi larvae to screen for bioactivity in an optimised laboratory setting. The compounds were bioactive in the low ng mL(-1) to high µg mL(-1) range. Polygodial was chosen for additional investigations, where it was shown that mean reductions in the proportions of larvae reaching stage E were highly repeatable both within (repeatability = 14 ± 9%) and between (intermediate precision = 17 ± 3%) independent experiments. An environmental extract had no effect on the larvae but exposing larvae to both the extract and polygodial reduced potency relative to polygodial alone. This change in potency stresses the need for caution when working with complex samples, as is routinely implemented when isolating natural compounds from their biological source. Overall, the outcomes of this study highlight the sensitivity of C. savignyi metamorphosis to environmental variations and chemical exposure.

  2. Metamorphosis of the invasive ascidian Ciona savignyi: environmental variables and chemical exposure

    PubMed Central

    Atalah, Javier; Selwood, Andrew I.; Kuhajek, Jeanne M.

    2016-01-01

    In this study, the effects of environmental variables on larval metamorphosis of the solitary ascidian Ciona savignyi were investigated in a laboratory setting. The progression of metamorphic changes were tracked under various temperature, photoperiod, substrate, larval density, and vessel size regimes. Metamorphosis was maximised at 18 °C, 12:12 h subdued light:dark, smooth polystyrene substrate, and 10 larvae mL−1 in a twelve-well tissue culture plate. Eliminating the air-water interface by filling culture vessels to capacity further increased the proportion of metamorphosed larvae; 87 ± 5% of larvae completed metamorphosis within 5 days compared to 45 ± 5% in control wells. The effects of the reference antifouling compounds polygodial, portimine, oroidin, chlorothalonil, and tolylfluanid on C. savignyi were subsequently determined, highlighting (1) the sensitivity of C. savignyi metamorphosis to chemical exposure and (2) the potential to use C. savignyi larvae to screen for bioactivity in an optimised laboratory setting. The compounds were bioactive in the low ng mL−1 to high µg mL−1 range. Polygodial was chosen for additional investigations, where it was shown that mean reductions in the proportions of larvae reaching stage E were highly repeatable both within (repeatability = 14 ± 9%) and between (intermediate precision = 17 ± 3%) independent experiments. An environmental extract had no effect on the larvae but exposing larvae to both the extract and polygodial reduced potency relative to polygodial alone. This change in potency stresses the need for caution when working with complex samples, as is routinely implemented when isolating natural compounds from their biological source. Overall, the outcomes of this study highlight the sensitivity of C. savignyi metamorphosis to environmental variations and chemical exposure. PMID:26966668

  3. Insulin-like genes in ascidians: findings in Ciona and hypotheses on the evolutionary origins of the pancreas

    PubMed Central

    Thompson, Jordan M.; Di Gregorio, Anna

    2014-01-01

    Insulin plays an extensively characterized role in the control of sugar metabolism, growth and homeostasis in a wide range of organisms. In vertebrate chordates, insulin is mainly produced by the beta cells of the endocrine pancreas, while in non-chordate animals insulin-producing cells are mainly found in the nervous system and/or scattered along the digestive tract. However, recent studies have indicated the notochord, the defining feature of the chordate phylum, as an additional site of expression of insulin-like peptides. Here we show that two of the three insulin-like genes identified in Ciona intestinalis, an invertebrate chordate with a dual life cycle, are first expressed in the developing notochord during embryogenesis and transition to distinct areas of the adult digestive tract after metamorphosis. In addition, we present data suggesting that the transcription factor Ciona Brachyury is involved in the control of notochord expression of at least one of these genes, Ciona insulin-like 2. Lastly, we review the information currently available on insulin-producing cells in ascidians and on pancreas-related transcription factors that might control their expression. PMID:25378051

  4. Evaluation of drug toxicity profiles based on the phenotypes of ascidian Ciona intestinalis.

    PubMed

    Mizotani, Yuji; Itoh, Shun; Hotta, Kohji; Tashiro, Etsu; Oka, Kotaro; Imoto, Masaya

    2015-08-07

    In vivo toxicity evaluation using model organisms is an important step for the development of new drugs. Here, we report that Ciona intestinalis, a chordate invertebrate, is beneficial to drug toxicity evaluation for the following reasons: rapid embryonic and larval development, resemblance to vertebrates, ease of management, low cost, transparent body, and low risk of ethical issues. The dynamic phenotypic change of Ciona larvae during metamorphosis prompted us to examine the effect of cytotoxic drugs on its development by quantifying six toxicity endpoints: degenerated tail size, ampulla length, rotation of body axis, stomach size, heart rate, and body size. As a result, mitochondrial respiratory inhibitors, tubulin polymerization/depolymerization inhibitors, or DNA/RNA synthesis inhibitors showed distinct toxicity profiles against these six endpoints, but drugs with the same targets showed a similar toxicity profile in Ciona. Our results suggest Ciona is an effective animal model for profiling drug toxicity and exploring the mechanisms of drugs with unknown targets.

  5. Distal Regeneration Involves the Age Dependent Activity of Branchial Sac Stem Cells in the Ascidian Ciona intestinalis.

    PubMed

    Jeffery, William R

    2015-02-01

    Tunicates have high capacities for regeneration but the underlying mechanisms and their relationship to life cycle progression are not well understood. Here we investigate the regeneration of distal structures in the ascidian tunicate Ciona intestinalis. Analysis of regenerative potential along the proximal-distal body axis indicated that distal organs, such as the siphons, their pigmented sensory organs, and the neural complex, could only be replaced from body fragments containing the branchial sac. Distal regeneration involves the formation of a blastema composed of cells that undergo cell proliferation prior to differentiation and cells that differentiate without cell proliferation. Both cell types originate in the branchial sac and appear in the blastema at different times after distal injury. Whereas the branchial sac stem cells are present in young animals, they are depleted in old animals that have lost their regeneration capacity. Thus Ciona adults contain a population of age-related stem cells located in the branchial sac that are a source of precursors for distal body regeneration.

  6. Toxicity assessment of the antifouling compound zinc pyrithione using early developmental stages of the ascidian Ciona intestinalis.

    PubMed

    Bellas, Juan

    2005-01-01

    This study investigated the toxicity of zinc pyrithione (Zpt) on the early stages of development of the ascidian Ciona intestinalis. Larval morphological abnormalities were studied after the exposure of C. intestinalis embryos at different stages of development. The median effective concentrations (EC50) ranged from 226-590 nM. The larval settlement stage was the most sensitive to Zpt. Toxic effects of Zpt on larval settlement were detected at 9 nM (EC10). The inhibition of C. intestinalis embryonic development was also used to study the loss of toxicity in Zpt solutions exposed to direct sunlight and laboratory UV light. The results showed that the toxicity of Zpt solutions decreased but did not disappear after 4 h exposure to direct sunlight (EC50 = 484 nM) or UV light (EC50 = 453 nM), compared to control Zpt solutions prepared in dark conditions. On the basis of the present data, predicted no effect concentrations of Zpt to C. intestinalis larvae are lower than predicted environmental concentrations of Zpt in certain polluted areas and therefore, may pose a risk to C. intestinalis populations.

  7. Complete mtDNA of Ciona intestinalis reveals extensive gene rearrangement and the presence of an atp8 and an extra trnM gene in ascidians.

    PubMed

    Gissi, Carmela; Iannelli, Fabio; Pesole, Graziano

    2004-04-01

    The complete mitochondrial genome (mtDNA) of the model organism Ciona intestinalis (Urochordata, Ascidiacea) has been amplified by long-PCR using specific primers designed on putative mitochondrial transcripts identified from publicly available mitochondrial-like expressed sequence tags. The C. intestinalis mtDNA encodes 39 genes: 2 rRNAs, 13 subunits of the respiratory complexes, including ATPase subunit 8 ( atp8), and 24 tRNAs, including 2 tRNA-Met with anticodons 5'-UAU-3'and 5'-CAU-3', respectively. All genes are transcribed from the same strand. This gene content seems to be a common feature of ascidian mtDNAs, as we have verified the presence of a previously undetected atp8 and of two trnM genes in the two other sequenced ascidian mtDNAs. Extensive gene rearrangement has been found in C. intestinalis with respect not only to the common Vertebrata/Cephalochordata/Hemichordata gene organization but also to other ascidian mtDNAs, including the cogeneric Ciona savignyi. Other features such as the absence of long noncoding regions, the shortness of rRNA genes, the low GC content (21.4%), and the absence of asymmetric base distribution between the two strands suggest that this genome is more similar to those of some protostomes than to deuterostomes.

  8. Germ cell regeneration-mediated, enhanced mutagenesis in the ascidian Ciona intestinalis reveals flexible germ cell formation from different somatic cells.

    PubMed

    Yoshida, Keita; Hozumi, Akiko; Treen, Nicholas; Sakuma, Tetsushi; Yamamoto, Takashi; Shirae-Kurabayashi, Maki; Sasakura, Yasunori

    2017-03-15

    The ascidian Ciona intestinalis has a high regeneration capacity that enables the regeneration of artificially removed primordial germ cells (PGCs) from somatic cells. We utilized PGC regeneration to establish efficient methods of germ line mutagenesis with transcription activator-like effector nucleases (TALENs). When PGCs were artificially removed from animals in which a TALEN pair was expressed, somatic cells harboring mutations in the target gene were converted into germ cells, this germ cell population exhibited higher mutation rates than animals not subjected to PGC removal. PGC regeneration enables us to use TALEN expression vectors of specific somatic tissues for germ cell mutagenesis. Unexpectedly, cis elements for epidermis, neural tissue and muscle could be used for germ cell mutagenesis, indicating there are multiple sources of regenerated PGCs, suggesting a flexibility of differentiated Ciona somatic cells to regain totipotency. Sperm and eggs of a single hermaphroditic, PGC regenerated animal typically have different mutations, suggesting they arise from different cells. PGCs can be generated from somatic cells even though the maternal PGCs are not removed, suggesting that the PGC regeneration is not solely an artificial event but could have an endogenous function in Ciona. This study provides a technical innovation in the genome-editing methods, including easy establishment of mutant lines. Moreover, this study suggests cellular mechanisms and the potential evolutionary significance of PGC regeneration in Ciona.

  9. Functions of a GnRH receptor heterodimer of the ascidian, Ciona intestinalis.

    PubMed

    Sakai, T; Aoyama, M; Kusakabe, T; Tsuda, M; Satake, H

    2008-01-01

    Gonadotropin-releasing hormone (GnRH) is a ten-amino acid peptide hormone that plays pivotal roles in reproduction in vertebrates and octopus. Recently, six GnRH forms (t-GnRH-3-8) and four GnRH receptor subtypes (Ci-GnRHR-1-4) were identified in the protochordate, Ciona intestinalis. In this study, we show the functional modulation of Ci-GnRHR-1 via heterodimerization with the orphan receptor subtype, Ci-GnRHR-4. The dimerization between Ci-GnRHR-1 and R-4 was detected by co-immunoprecipitation and immunoblot analysis. Binding assays confirmed the binding of t-GnRHs to Ci-GnRHR-1 but not to R-4, and verified no alternation in ligand-binding affinity between Ci-GnRHR-1 homodimer and Ci-GnRHRI&4 heterodimer. The heterodimer was found to stimulate the elevation of intracellular calcium, time-extension of ERK phosphorylation, and up-regulation of cell proliferation, all in a ligand specific manner, compared with the Ci-GnRHR-1 homodimer. In combination, these results indicated that Ci-GnRHR-4 is not an inactive receptor, but a modulatory factor for Ci-GnRHR-1 in C. intestinalis.

  10. Genomewide gene-associated microsatellite markers for the model invasive ascidian, Ciona intestinalis species complex.

    PubMed

    Lin, Yaping; Chen, Yiyong; Xiong, Wei; Zhan, Aibin

    2016-05-01

    The vase tunicate, Ciona intestinalis species complex, has become a good model for ecological and evolutionary studies, especially those focusing on microevolution associated with rapidly changing environments. However, genomewide genetic markers are still lacking. Here, we characterized a large set of genomewide gene-associated microsatellite markers for C. intestinalis spA (=C. robusta). Bioinformatic analysis identified 4654 microsatellites from expressed sequence tags (ESTs), 2126 of which successfully assigned to chromosomes were selected for further analysis. Based on the distribution evenness on chromosomes, function annotation and suitability for primer design, we chose 545 candidate microsatellites for further characterization. After amplification validation and variation assessment, 218 loci were polymorphic in at least one of the two populations collected from the coast of Arenys de Mar, Spain (N = 24-48), and Cape Town, South Africa (N = 24-33). The number of alleles, observed heterozygosity and expected heterozygosity ranged from 2 to 11, 0 to 0.833 and 0.021 to 0.818, and from 2 to 10, 0 to 0.879 and 0.031 to 0.845 for the Spanish and African populations, respectively. When all microsatellites were tested for cross-species utility, only 60 loci (25.8%) could be successfully amplified and all loci were polymorphic in C. intestinalis spB. A high level of genomewide polymorphism is likely responsible for the low transferability. The large set of microsatellite markers characterized here is expected to provide a useful genomewide resource for ecological and evolutionary studies using C. intestinalis as a model.

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

    PubMed

    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.

  12. Structural and functional properties of CiNTH, an endonuclease III homologue of the ascidian Ciona intestinalis: critical role of N-terminal region.

    PubMed

    Kato, Seiji; Hashiguchi, Kazunari; Igarashi, Kento; Moriwaki, Takahito; Yonekura, Shin-Ichiro; Zhang-Akiyama, Qiu-Mei

    2012-01-01

    Oxidatively damaged bases in DNA can cause cell death, mutation and/or cancer induction. To overcome such deleterious effects of DNA base oxidation, cells are equipped with base excision repair (BER) initiated by DNA glycosylases. Endonuclease III (Nth), a major DNA glycosylase, mainly excises oxidatively damaged pyrimidines from DNA. The aims of this study were to obtain an overview of the repair mechanism of oxidatively damaged bases and to elucidate the function of BER in maintaining genome stability during embryogenesis and development. In this study, we used the ascidian Ciona intestinalis because at every developmental stage it is possible to observe the phenotype of individuals with DNA damage or mutations. Sequence alignment analysis revealed that the amino acid sequence of Ciona intestinalis Nth homologue (CiNTH) had high homology with those of Escherichia coli, Saccharomyces cerevisiae, Schizosaccharomyces pombe, Caenorhabditis elegans and human Nth homologues. It was evident that two domains, the Helix-hairpin-Helix and 4Fe-4S cluster domains that are critical regions for the Nth activity, are well conserved in CiNTH. CiNTH efficiently complemented the sensitivity of E. coli nth nei mutant to H(2)O(2). CiNTH was bifunctional, with DNA glycosylase and AP lyase activities. It removed thymine glycol, 5-formyluracil and 8-oxoguanine paired with G from DNA via a β-elimination reaction. Interestingly, the N-terminal 44 amino acids were essential for the DNA glycosylase activity of CiNTH.

  13. Nitric oxide affects ERK signaling through down-regulation of MAP kinase phosphatase levels during larval development of the ascidian Ciona intestinalis.

    PubMed

    Castellano, Immacolata; Ercolesi, Elena; Palumbo, Anna

    2014-01-01

    In the ascidian Ciona intestinalis larval development and metamorphosis require a complex interplay of events, including nitric oxide (NO) production, MAP kinases (ERK, JNK) and caspase-3 activation. We have previously shown that NO levels affect the rate of metamorphosis, regulate caspase activity and promote an oxidative stress pathway, resulting in protein nitration. Here, we report that NO down-regulates MAP kinase phosphatases (mkps) expression affecting positively ERK signaling. By pharmacological approach, we observed that the reduction of endogenous NO levels caused a decrease of ERK phosphorylation, whereas increasing levels of NO induced ERK activation. We have also identified the ERK gene network affected by NO, including mpk1, mpk3 and some key developmental genes by quantitative gene expression analysis. We demonstrate that NO induces an ERK-independent down-regulation of mkp1 and mkp3, responsible for maintaining the ERK phosphorylation levels necessary for transcription of key metamorphic genes, such as the hormone receptor rev-erb and the van willebrand protein vwa1c. These results add new insights into the role played by NO during larval development and metamorphosis in Ciona, highlighting the cross-talk between different signaling pathways.

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

    PubMed

    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.

  15. A pipeline for the systematic identification of non-redundant full-ORF cDNAs for polymorphic and evolutionary divergent genomes: Application to the ascidian Ciona intestinalis

    SciTech Connect

    Gilchrist, Michael J.; Sobral, Daniel; Khoueiry, Pierre; Daian, Fabrice; Laporte, Batiste; Patrushev, Ilya; Matsumoto, Jun; Dewar, Ken; Hastings, Kenneth E. M.; Satou, Yutaka; Lemaire, Patrick; Rothbächer, Ute

    2015-05-27

    Genome-wide resources, such as collections of cDNA clones encoding for complete proteins (full-ORF clones), are crucial tools for studying the evolution of gene function and genetic interactions. Non-model organisms, in particular marine organisms, provide a rich source of functional diversity. Marine organism genomes are, however, frequently highly polymorphic and encode proteins that diverge significantly from those of well-annotated model genomes. The construction of full-ORF clone collections from non-model organisms is hindered by the difficulty of predicting accurately the N-terminal ends of proteins, and distinguishing recent paralogs from highly polymorphic alleles. We also report a computational strategy that overcomes these difficulties, and allows for accurate gene level clustering of transcript data followed by the automated identification of full-ORFs with correct 5'- and 3'-ends. It is robust to polymorphism, includes paralog calling and does not require evolutionary proximity to well annotated model organisms. Here, we developed this pipeline for the ascidian Ciona intestinalis, a highly polymorphic member of the divergent sister group of the vertebrates, emerging as a powerful model organism to study chordate gene function, Gene Regulatory Networks and molecular mechanisms underlying human pathologies. Furthermore, using this pipeline we have generated the first full-ORF collection for a highly polymorphic marine invertebrate. It contains 19,163 full-ORF cDNA clones covering 60% of Ciona coding genes, and full-ORF orthologs for approximately half of curated human disease-associated genes.

  16. A pipeline for the systematic identification of non-redundant full-ORF cDNAs for polymorphic and evolutionary divergent genomes: Application to the ascidian Ciona intestinalis.

    PubMed

    Gilchrist, Michael J; Sobral, Daniel; Khoueiry, Pierre; Daian, Fabrice; Laporte, Batiste; Patrushev, Ilya; Matsumoto, Jun; Dewar, Ken; Hastings, Kenneth E M; Satou, Yutaka; Lemaire, Patrick; Rothbächer, Ute

    2015-08-15

    Genome-wide resources, such as collections of cDNA clones encoding for complete proteins (full-ORF clones), are crucial tools for studying the evolution of gene function and genetic interactions. Non-model organisms, in particular marine organisms, provide a rich source of functional diversity. Marine organism genomes are, however, frequently highly polymorphic and encode proteins that diverge significantly from those of well-annotated model genomes. The construction of full-ORF clone collections from non-model organisms is hindered by the difficulty of predicting accurately the N-terminal ends of proteins, and distinguishing recent paralogs from highly polymorphic alleles. We report a computational strategy that overcomes these difficulties, and allows for accurate gene level clustering of transcript data followed by the automated identification of full-ORFs with correct 5'- and 3'-ends. It is robust to polymorphism, includes paralog calling and does not require evolutionary proximity to well annotated model organisms. We developed this pipeline for the ascidian Ciona intestinalis, a highly polymorphic member of the divergent sister group of the vertebrates, emerging as a powerful model organism to study chordate gene function, Gene Regulatory Networks and molecular mechanisms underlying human pathologies. Using this pipeline we have generated the first full-ORF collection for a highly polymorphic marine invertebrate. It contains 19,163 full-ORF cDNA clones covering 60% of Ciona coding genes, and full-ORF orthologs for approximately half of curated human disease-associated genes.

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

    PubMed

    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.

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

    PubMed Central

    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 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. PMID:25788553

  19. Evolution of the Chordate Regeneration Blastema: Differential Gene Expression and Conserved Role of Notch Signaling During Siphon Regeneration in the Ascidian Ciona

    PubMed Central

    Hamada, Mayuko; Goricki, Spela; Byerly, Mardi S.; Satoh, Noriyuki; Jeffery, William R.

    2015-01-01

    The regeneration of the oral siphon (OS) and other distal structures in the ascidian Ciona intestinalis occurs by epimorphosis involving the formation of a blastema of proliferating cells. Despite the longstanding use of Ciona as a model in molecular developmental biology, regeneration in this system has not been previously explored by molecular analysis. Here we have employed microarray analysis and quantitative real time RT-PCR to identify genes with differential expression profiles during OS regeneration. The majority of differentially expressed genes were downregulated during OS regeneration, suggesting roles in normal growth and homeostasis. However, a subset of differentially expressed genes was upregulated in the regenerating OS, suggesting functional roles during regeneration. Among the upregulated genes were key members of the Notch signaling pathway, including those encoding the delta and jagged ligands, two fringe modulators, and to a lesser extent the notch receptor. In situ hybridization showed a complementary pattern of delta1 and notch gene expression in the blastema of the regenerating OS. Chemical inhibition of the Notch signaling pathway reduced the levels of cell proliferation in the branchial sac, a stem cell niche that contributes progenitor cells to the regenerating OS, and in the OS regeneration blastema, where siphon muscle fibers eventually re-differentiate. Chemical inhibition also prevented the replacement of oral siphon pigment organs, sensory receptors rimming the entrance of the OS, and siphon muscle fibers, but had no effects on the formation of the wound epidermis. Since Notch signaling is involved in the maintenance of proliferative activity in both the Ciona and vertebrate regeneration blastema, the results suggest a conserved evolutionary role of this signaling pathway in chordate regeneration. The genes identified in this investigation provide the foundation for future molecular analysis of OS regeneration. PMID:26206613

  20. Transposon-mediated enhancer detection reveals the location, morphology and development of the cupular organs, which are putative hydrodynamic sensors, in the ascidian Ciona intestinalis.

    PubMed

    Ohta, Naoyuki; Horie, Takeo; Satoh, Nori; Sasakura, Yasunori

    2010-11-01

    The adult of the ascidian Ciona intestinalis has cupular organs, i.e., putative hydrodynamic sensors, at the atrial epithelium. The cupular organ consists of support cells and sensory neurons, and it extends a gelatinous matrix, known as a cupula, toward the atrial cavity. These characteristics are shared with sensory hair cells in the vertebrate inner ear and lateral line neuromasts in fish and amphibians, which suggests an evolutionary link between the cupular organ and these vertebrate hydrodynamic sensors. In the present study, we have isolated and investigated two transposon-mediated enhancer detection lines that showed GFP expression in support cells of the cupular organs. Using the enhancer detection lines and neuron marker transgenic lines, we describe the position, morphology, and development of the cupular organs. Cupular organs were found at the atrial epithelium, but not in the branchial epithelium. We found that cupular organs are also present along the dorsal fold and the gonoducts. The cells lining the pre-atrial opening in juveniles are presumably precursor cells of the cupular organ. To our knowledge, the present study is the first precise description of the ascidian cupular organ, providing evidence that may help to resolve discrepancies among previous studies on the organ.

  1. Effects of the azole fungicide Imazalil on the development of the ascidian Ciona intestinalis (Chordata, Tunicata): morphological and molecular characterization of the induced phenotype.

    PubMed

    Zega, Giuliana; De Bernardi, Fiorenza; Groppelli, Silvia; Pennati, Roberta

    2009-02-19

    Imazalil (IMA) is a fungicide that is used extensively in fruit plantations and post-harvest treatments, but has teratogenic effects on vertebrate development, possibly due to the perturbation of retinoic acid (RA) levels in the embryo. Ascidians are sessile marine invertebrate chordates that develop through a tadpole larva, with a body plan that shares basic homologies with vertebrates. In this work, we tested the effects of IMA on the development of the solitary ascidian Ciona intestinalis by treating two-cell stage embryos with a range of concentrations (0.1, 0.5, 1, 2.5, 5, 10, 20 and 50microThe fungicide significantly altered ascidian development even at low concentrations and its effects were dose-dependent. Probit analysis revealed that the median lethal concentration, LC(50), was 4.87microM and the median teratogenic concentration, TC(50), was 0.73microM. Larvae developing from embryos exposed to IMA showed malformations of the anterior structures, which became more severe as IMA concentration increased. In particular, the anterior nervous system and the sensory vesicle were reduced, and the pigmented organs (the ocellus and the otolith) progressively lost their pigmentation. The larval phenotype induced by 5microM IMA exposure was further characterized by means of molecular analysis, through whole mount in situ hybridization with probes for genes related to the nervous system: Ci-Otp, Ci-GAD, Ci-POU IV, which are markers of the anterior neuro-ectoderm, the central nervous system and the peripheral nervous system respectively, and Ci-Hox-1, a gene specifically activated by RA, and Ci-Aldh2, a gene for aldehyde dehydrogenase, which is involved in RA synthesis. The altered expression of Ci-Otp, Ci-GAD, Ci-POU IV in 5microM IMA-exposed larvae compared to control larvae showed that this fungicide could affect the differentiation of the anterior nervous system, particularly of the sensory vesicle neurons. Recent studies suggest a similarity between IMA- and RA

  2. cDNA cloning, localization, and candidate binding partners of acid-extractable vitelline-coat protein Ci-v-Themis-like in the ascidian Ciona intestinalis.

    PubMed

    Otsuka, Kei; Yamada, Lixy; Sawada, Hitoshi

    2013-10-01

    Ascidians are hermaphrodites, although several ascidian species show self-sterility because of the occurrence of a self/nonself-recognition system called the self-incompatibility system. We previously reported that two pairs of sperm polycystin 1-like receptors, s-Themis-A and s-Themis-B, and egg fibrinogen-like ligands, v-Themis-A and v-Themis-B, are responsible for self-incompatibility in the ascidian Ciona intestinalis. Our previous results showed that v-Themis-A and v-Themis-B were hardly extracted from the vitelline coat (VC) by acid treatment, which is not in accordance with a report that an acid-extractable VC factor has the ability to distinguish self- from nonself-sperm. These results led us to explore a novel factor from acid-extractable VC proteins that could be involved in self-incompatibility. Here, we report cDNA cloning, expression, and localization of Ci-v-Themis-like, a major acid-extractable VC protein. This protein has a fibrinogen-like domain, as do v-Themis-A and v-Themis-B, but it showed no polymorphisms. Phylogenic analysis suggested that Ci-v-Themis-like is an ancestral protein of v-Themis-A and v-Themis-B. Whole mount in situ hybridization revealed that Ci-v-Themis-like mRNA is expressed in the ovary and testis. Western blotting and immunocytochemistry showed the occurrence of Ci-v-Themis-like in developing oocytes and on the VC of mature eggs. Yeast two-hybrid screenings using testis and ovary libraries revealed candidate interacting proteins; among these candidates, we succeeded in identifying several testis-specific proteins, including sperm proteases and coiled-coil-domain-containing proteins. The results suggest that Ci-v-Themis-like and its binding partners are involved in sperm binding to the VC prior to the allorecognition process during C. intestinalis fertilization.

  3. Differential gene regulation by V(IV) and V (V) ions in the branchial sac, intestine, and blood cells of a vanadium-rich ascidian, Ciona intestinalis.

    PubMed

    Kume, Satoshi; Ueki, Tatsuya; Matsuoka, Hiroki; Hamada, Mayuko; Satoh, Nori; Michibata, Hitoshi

    2012-10-01

    Ascidians are hyperaccumulators that have been studied in detail. Proteins and genes involved in the accumulation process have been identified, but regulation of gene expression related to vanadium accumulation remains unknown. To gain insights into the regulation of gene expression by vanadium in a genome-wide manner, we performed a comprehensive study on the effect of excess vanadium ions on a vanadium-rich ascidian, Ciona intestinalis, using a microarray. RT-PCR and enzyme activity assay were performed from the perspective of redox and accumulation of metal ions in each tissue. Glutathione metabolism-related proteins were significantly up-regulated by V(IV) treatment. Several genes involved in the transport of vanadium and protons, such as Nramp and V-ATPase, were significantly up-regulated by V(IV) treatment. We observed significant up-regulation of glutathione synthesis and degradation pathways in the intestine and branchial sac. In blood cells, expression of Ci-Vanabin4, glutathione reductase activity, glutathione levels, and vanadium concentration increased after V(IV) treatment. V(IV) treatment induced significant changes related to vanadium exclusion, seclusion, and redox pathways in the intestine and branchial sac. It also induced an enhancement of the vanadium reduction and accumulation cascade in blood cells. These differential responses in each tissue in the presence of excess vanadium ions suggest that vanadium accumulation and reduction may have regulatory functions. This is the first report on the gene regulation by the treatment of vanadium-rich ascidians with excess vanadium ions. It provided much information for the mechanism of regulation of gene expression related to vanadium accumulation.

  4. A pipeline for the systematic identification of non-redundant full-ORF cDNAs for polymorphic and evolutionary divergent genomes: Application to the ascidian Ciona intestinalis

    DOE PAGES

    Gilchrist, Michael J.; Sobral, Daniel; Khoueiry, Pierre; ...

    2015-05-27

    Genome-wide resources, such as collections of cDNA clones encoding for complete proteins (full-ORF clones), are crucial tools for studying the evolution of gene function and genetic interactions. Non-model organisms, in particular marine organisms, provide a rich source of functional diversity. Marine organism genomes are, however, frequently highly polymorphic and encode proteins that diverge significantly from those of well-annotated model genomes. The construction of full-ORF clone collections from non-model organisms is hindered by the difficulty of predicting accurately the N-terminal ends of proteins, and distinguishing recent paralogs from highly polymorphic alleles. We also report a computational strategy that overcomes these difficulties,more » and allows for accurate gene level clustering of transcript data followed by the automated identification of full-ORFs with correct 5'- and 3'-ends. It is robust to polymorphism, includes paralog calling and does not require evolutionary proximity to well annotated model organisms. Here, we developed this pipeline for the ascidian Ciona intestinalis, a highly polymorphic member of the divergent sister group of the vertebrates, emerging as a powerful model organism to study chordate gene function, Gene Regulatory Networks and molecular mechanisms underlying human pathologies. Furthermore, using this pipeline we have generated the first full-ORF collection for a highly polymorphic marine invertebrate. It contains 19,163 full-ORF cDNA clones covering 60% of Ciona coding genes, and full-ORF orthologs for approximately half of curated human disease-associated genes.« less

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

    PubMed

    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.

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

    PubMed

    Ferro, Diana; Franchi, Nicola; Mangano, Valentina; Bakiu, Rigers; Cammarata, Matteo; Parrinello, Nicolò; Santovito, Gianfranco; Ballarin, Loriano

    2013-09-15

    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 allowing the survival of C. intestinalis in continued, elevated presence of metals in the environment.

  7. Identification and localization of the sperm CRISP family protein CiUrabin involved in gamete interaction in the ascidian Ciona intestinalis.

    PubMed

    Yamaguchi, Akira; Saito, Takako; Yamada, Lixy; Taniguchi, Hisaaki; Harada, Yoshito; Sawada, Hitoshi

    2011-07-01

    Ascidians are hermaphrodites, and most release sperm and eggs nearly simultaneously. Many species, including Halocynthia roretzi and Ciona intestinalis, are self-sterile. We previously reported that the interaction between a 12 EGF-like repeat-containing vitelline-coat (VC) protein, HrVC70, and a sperm GPI-anchored CRISP, HrUrabin, in lipid rafts plays a key role in self-/nonself-recognizable gamete interaction in H. roretzi. On the other hand, we recently identified two pairs of polymorphic genes responsible for self-incompatibility in C. intestinalis by positional cloning: The sperm polycystin 1-like receptors s-Themis-A/B and its fibrinogen-like ligand v-Themis-A/B on the VC. However, it is not known if the orthologs of HrVC70 and HrUrabin also participate in gamete interaction in C. intestinalis since they are from different orders. Here, we tested for a C. intestinalis ortholog (CiUrabin) of HrUrabin by searching the genome database and proteomes of sperm lipid rafts. The identified CiUrabin belongs to the CRISP family, with a PR domain and a GPI-anchor-attachment site. CiUrabin appears to be specifically expressed in the testis and localized at the surface of the sperm head, as revealed by Northern blotting and immunocytochemistry, respectively. The specific interaction between CiVC57, a C. intestinalis ortholog of HrVC70, and CiUrabin was confirmed by Far Western analysis, similarly to the interaction between HrVC70 and HrUrabin. The molecular interaction between CiVC57 and CiUrabin may be involved in the primary binding of sperm to the VC prior to the allorecognition process, mediated by v-Themis-A/B and s-Themis-A/B, during fertilization of C. intestinalis.

  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.

    PubMed

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

    PubMed

    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.

  10. How Fast Is the Sessile Ciona?

    PubMed Central

    Berná, Luisa; Alvarez-Valin, Fernando; D'Onofrio, Giuseppe

    2009-01-01

    Genomewide analyses of distances between orthologous gene pairs from the ascidian species Ciona intestinalis and Ciona savignyi were compared with those of vertebrates. Combining this data with a detailed and careful use of vertebrate fossil records, we estimated the time of divergence between the two ascidians nearly 180 My. This estimation was obtained after correcting for the different substitution rates found comparing several groups of chordates; indeed we determine here that on average Ciona species evolve 50% faster than vertebrates. PMID:20052388

  11. Stress response in the ascidian Ciona intestinalis: transcriptional profiling of genes for the heat shock protein 70 chaperone system under heat stress and endoplasmic reticulum stress.

    PubMed

    Fujikawa, Tetsuya; Munakata, Takeo; Kondo, Shin-ichi; Satoh, Nori; Wada, Shuichi

    2010-03-01

    The genome of Ciona intestinalis contains eight genes for HSP70 superfamily proteins, 36 genes for J-proteins, a gene for a J-like protein, and three genes for BAG family proteins. To understand the stress responses of genes in the HSP70 chaperone system comprehensively, the transcriptional profiles of these 48 genes under heat stress and endoplasmic reticulum (ER) stress were studied using real-time reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. Heat stress treatment increased the messenger RNA (mRNA) levels of six HSP70 superfamily genes, eight J-protein family genes, and two BAG family genes. In the cytoplasmic group of the DnaK subfamily of the HSP70 family, Ci-HSPA1/6/7-like was the only heat-inducible gene and Ci-HSPA2/8 was the only constitutively active gene which showed striking simplicity in comparison with other animals that have been examined genome-wide so far. Analyses of the time course and temperature dependency of the heat stress responses showed that the induction of Ci-HSPA1/6/7-like expression rises to a peak after heat stress treatment at 28 degrees C (10 degrees C upshift from control temperature) for 1 h. ER stress treatment with Brefeldin A, a drug that is known to act as ER stress inducer, increased the mRNA levels of four HSP70 superfamily genes and four J-protein family genes. Most stress-inducible genes are conserved between Ciona and vertebrates, as expected from a close evolutionary relationship between them. The present study characterized the stress responses of HSP70 chaperone system genes in Ciona for the first time and provides essential data for comprehensive understanding of the functions of the HSP70 chaperone system.

  12. Cell lineage and cis-regulation for a unique GABAergic/glycinergic neuron type in the larval nerve cord of the ascidian Ciona intestinalis.

    PubMed

    Nishitsuji, Koki; Horie, Takeo; Ichinose, Aoi; Sasakura, Yasunori; Yasuo, Hitoyoshi; Kusakabe, Takehiro G

    2012-02-01

    The tunicate Ciona intestinalis larva has a simple central nervous system (CNS), consisting of fewer than 400 cells, which is homologous to the vertebrate CNS. Recent studies have revealed neuronal types and networks in the larval CNS of C. intestinalis, yet their cell lineage and the molecular mechanism by which particular types of neurons are specified and differentiate remain poorly understood. Here, we report cell lineage origin and a cis-regulatory module for the anterior caudal inhibitory neurons (ACINs), a putative component of the central pattern generator regulating swimming locomotion. The vesicular GABA⁄ glycine transporter gene Ci-VGAT, a specific marker for GABAergic ⁄ glycinergic neurons, is expressed in distinct sets of neurons, including ACINs of the tail nerve cord and others in the brain vesicle and motor ganglion. Comparative genomics analysis between C. intestinalis and Ciona savignyi and functional analysis in vivo identified the cis-regulatory module responsible for Ci-VGAT expression in ACINs. Our cell lineage analyses inferred that ACINs derive from A11.116 cells, which have been thought to solely give rise to glial ependymal cells of the lateral wall of the nerve cord. The present findings will provide a solid basis for future studies addressing the molecular mechanism underlying specification of ACINs, which play a critical role in controlling larval locomotion

  13. Application of the cis-regulatory region of a heat-shock protein 70 gene to heat-inducible gene expression in the ascidian Ciona intestinalis.

    PubMed

    Kawaguchi, Akane; Utsumi, Nanami; Morita, Maki; Ohya, Aya; Wada, Shuichi

    2015-01-01

    Temporally controlled induction of gene expression is a useful technique for analyzing gene function. To make such a technique possible in Ciona intestinalis embryos, we employed the cis-regulatory region of the heat-shock protein 70 (HSP70) gene Ci-HSPA1/6/7-like for heat-inducible gene expression in C. intestinalis embryos. We showed that Ci-HSPA1/6/7-like becomes heat shock-inducible by the 32-cell stage during embryogenesis. The 5'-upstream region of Ci-HSPA1/6/7-like, which contains heat-shock elements indispensable for heat-inducible gene expression, induces the heat shock-dependent expression of a reporter gene in the whole embryo from the 32-cell to the middle gastrula stages and in progressively restricted areas of embryos in subsequent stages. We assessed the effects of heat-shock treatments in different conditions on the normality of embryos and induction of transgene expression. We evaluated the usefulness of this technique through overexpression experiments on the well-characterized, developmentally relevant gene, Ci-Bra, and showed that this technique is applicable for inferring the gene function in C. intestinalis.

  14. Two Decades of Ascidian Developmental Biology: A Personal Research Story.

    PubMed

    Satoh, Noriyuki

    2016-01-01

    Ascidians are the closest relatives of vertebrates. Their utility in experimental embryology has been well recognized because of their simple mode of embryogenesis to form tadpole larvae with a basal chordate body plan. Approximately two decades of research, including decoding of the Ciona genome, have promoted ascidians as one of the best systems for exploring genome-wide mechanisms of developmental transcriptional control and chordate evolution.

  15. Mutation studies in ascidians: a review.

    PubMed

    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.

  16. The Ciona intestinalis cleavage clock is independent of DNA methylation.

    PubMed

    Suzuki, Miho M; Mori, Tomoko; Satoh, Noriyuki

    2016-10-01

    The initiation of embryonic gene expression in ascidian embryos appears to be tightly regulated by the number of DNA replication cycles. DNA methylation is thought to contribute to the clock mechanism that counts the rounds of DNA replication. We used mass spectrometry and whole genome bisulfite sequencing to characterize DNA methylation changes that occur in early developmental stages of the ascidian, Ciona intestinalis. We found that global DNA methylation in early Ciona development was static, and a base-wise comparison between the genomes of consecutive developmental stages found no DNA demethylation that was related to zygotic gene activation. Additionally, 5hmC was hardly detected by mass spectrometry in the developmental samples, suggesting a lack of demethylation mediated by ten eleven translocation (TET) methylcytosine dioxygenase in C. intestinalis. We conclude that DNA methylation is not involved in regulating DNA replication-dependent transcriptional activation.

  17. Identification of autophagy genes in Ciona intestinalis: a new experimental model to study autophagy mechanism.

    PubMed

    Godefroy, Nelly; Hoa, Céline; Tsokanos, Foivos; Le Goff, Emilie; Douzery, Emmanuel J P; Baghdiguian, Stephen; Martinand-Mari, Camille

    2009-08-01

    Programmed cell death (PCD) is a mechanism implicated in many physiological and pathological processes. Until recently, apoptosis (self-killing) was the most largely studied mechanism of PCD but a growing number of laboratories are now interested in autophagy (self-eating). In the past few years data showing a tight link between both pathways has accumulated. Until now our laboratory used Ciona intestinalis, a chordate model in which in vivo experiments are possible, to study apoptosis. Recently, we showed that autophagy also occurs in the development of Ciona intestinalis and that the specific markers of both types of death are found in the same tissues and/or in the same cells. These results drove us to postulate that Ciona intestinalis can be a good model to study the link between apoptosis and autophagy. In this article, we conducted an in silico study of autophagy genes. We explored the genomes of Ciona intestinalis, of the second ascidian Ciona savignyi, and those of the classical biological models (Saccharomyces cerevisiae, Drosophila melanogaster, Caenorhabditis elegans and Homo sapiens) to extract and compare autophagy gene sequences. This genomic study was completed by an analysis of: (i) mRNA profile expression during development and (ii) the localization of Beclin protein by immunofluorescent staining in the Ciona intestinalis larvae. Taken together, the results allowed us to conclude that a complex autophagic machinery is present in Ciona intestinalis. Actually, the number of autophagy genes in Ciona intestinalis is comparable to the number of autophagy genes in human.

  18. Ascidian fauna (Tunicata, Ascidiacea) of subantarctic and temperate regions of Chile.

    PubMed

    Turon, Xavier; Cañete, Juan I; Sellanes, Javier; Rocha, Rosana M; López-Legentil, Susanna

    2016-03-21

    We studied the ascidian fauna from two zones located in subantarctic (Punta Arenas, latitude 53º) and temperate Chile (Coquimbo, latitude 29º). The different oceanographic features of the two zones, with influence of the Humboldt Current in the north and the Cape Horn Current System and freshwater inputs in the south, led to markedly different ascidian faunas. A total of 22 species were recorded, with no shared species across the two areas (11 species each). The new species Polyzoa iosune is described, Lissoclinum perforatum is found for the first time in the Pacific Ocean, and Synoicum georgianum and Polyzoa minor are new to the Chilean fauna. The populations of Ciona in the Coquimbo area (formerly attributed to Ciona intestinalis) correspond to the species Ciona robusta. A total of 35 Cytochrome oxidase (COI) sequences of the standard barcode region have been obtained for 17 of the 22 species reported.

  19. Peptidomic analysis of the central nervous system of the protochordate, Ciona intestinalis: homologs and prototypes of vertebrate peptides and novel peptides.

    PubMed

    Kawada, Tsuyoshi; Ogasawara, Michio; Sekiguchi, Toshio; Aoyama, Masato; Hotta, Kohji; Oka, Kotaro; Satake, Honoo

    2011-06-01

    The phylogenetic position of ascidians as the chordate invertebrates closest to vertebrates suggests that they might possess homologs and/or prototypes of vertebrate peptide hormones and neuropeptides as well as ascidian-specific peptides. However, only a small number of peptides have so far been identified in ascidians. In the present study, we have identified various peptides in the ascidian, Ciona intestinalis. Mass spectrometry-based peptidomic analysis detected 33 peptides, including 26 novel peptides, from C. intestinalis. The ascidian peptides are largely classified into three categories: 1) prototypes and homologs of vertebrate peptides, such as galanin/galanin-like peptide, which have never been identified in any invertebrates; 2) peptides partially homologous with vertebrate peptides, including novel neurotesin-like peptides; 3) novel peptides. These results not only provide evidence that C. intestinalis possesses various homologs and prototypes of vertebrate neuropeptides and peptide hormones but also suggest that several of these peptides might have diverged in the ascidian-specific evolutionary lineage. All Ciona peptide genes were expressed in the neural complex, whereas several peptide gene transcripts were also distributed in peripheral tissues, including the ovary. Furthermore, a Ciona neurotensin-like peptide, C. intestinalis neurotensin-like peptide 6, was shown to down-regulate growth of Ciona vitellogenic oocytes. These results suggest that the Ciona peptides act not only as neuropeptides in the neural tissue but also as hormones in nonneuronal tissues and that ascidians, unlike other invertebrates, such as nematodes, insects, and sea urchins, established an evolutionary origin of the peptidergic neuroendocrine, endocrine, and nervous systems of vertebrates with certain specific molecular diversity.

  20. The repertoire of G protein-coupled receptors in the sea squirt Ciona intestinalis

    PubMed Central

    2008-01-01

    Background G protein-coupled receptors (GPCRs) constitute a large family of integral transmembrane receptor proteins that play a central role in signal transduction in eukaryotes. The genome of the protochordate Ciona intestinalis has a compact size with an ancestral complement of many diversified gene families of vertebrates and is a good model system for studying protochordate to vertebrate diversification. An analysis of the Ciona repertoire of GPCRs from a comparative genomic perspective provides insight into the evolutionary origins of the GPCR signalling system in vertebrates. Results We have identified 169 gene products in the Ciona genome that code for putative GPCRs. Phylogenetic analyses reveal that Ciona GPCRs have homologous representatives from the five major GRAFS (Glutamate, Rhodopsin, Adhesion, Frizzled and Secretin) families concomitant with other vertebrate GPCR repertoires. Nearly 39% of Ciona GPCRs have unambiguous orthologs of vertebrate GPCR families, as defined for the human, mouse, puffer fish and chicken genomes. The Rhodopsin family accounts for ~68% of the Ciona GPCR repertoire wherein the LGR-like subfamily exhibits a lineage specific gene expansion of a group of receptors that possess a novel domain organisation hitherto unobserved in metazoan genomes. Conclusion Comparison of GPCRs in Ciona to that in human reveals a high level of orthology of a protochordate repertoire with that of vertebrate GPCRs. Our studies suggest that the ascidians contain the basic ancestral complement of vertebrate GPCR genes. This is evident at the subfamily level comparisons since Ciona GPCR sequences are significantly analogous to vertebrate GPCR subfamilies even while exhibiting Ciona specific genes. Our analysis provides a framework to perform future experimental and comparative studies to understand the roles of the ancestral chordate versions of GPCRs that predated the divergence of the urochordates and the vertebrates. PMID:18452600

  1. Gene expression profiles of FABP genes in protochordates, Ciona intestinalis and Branchiostoma belcheri.

    PubMed

    Orito, Wataru; Ohhira, Fuyuko; Ogasawara, Michio

    2015-11-01

    Fatty-acid-binding proteins (FABPs) are small intracellular proteins associated with the transportation of fatty acids. Members of the FABPs share similar amino acid sequences and tertiary structures and form, together with a member of the cellular retinol-binding proteins (CRBPs), the intracellular-lipid-binding protein (iLBP) family. In vertebrates, several types of FABP have been isolated and classified into three subfamilies: 2-4. In invertebrates, several FABP-related proteins have been reported in protostomes and amphioxus; however, little is known about the relationship between their phylogenetic positions and expression patterns. We have performed a genome-wide survey of FABP-related genes in protochordates: amphioxus Branchiostoma belcheri and the ascidian Ciona intestinalis. Comprehensive BLAST searches in NCBI and the Ciona Ghost Database by using amino acid sequences of all FABPs have revealed that the ascidian C. intestinalis and amphioxus B. belcheri contain six and seven FABP-related genes in their haploid genomes, respectively. Expression pattern analyses by whole-mount in situ hybridization in Ciona transparent juveniles and serial-section in situ hybridizations in adult amphioxus have revealed that all genes are mainly expressed in the postpharyngeal digestive tract. In particular, the expression of FABP-related genes of subfamily-2 (liver/ileum type) and subfamily-3 (intestinal type) in the ascidian pyloric gland and amphioxus hepatic cecum provides insight into the evolution of hepatic-related structures of chordates and FABP-related genes.

  2. Ciona as a Simple Chordate Model for Heart Development and Regeneration

    PubMed Central

    Anderson, Heather Evans; Christiaen, Lionel

    2016-01-01

    Cardiac cell specification and the genetic determinants that govern this process are highly conserved among Chordates. Recent studies have established the importance of evolutionarily-conserved mechanisms in the study of congenital heart defects and disease, as well as cardiac regeneration. As a basal Chordate, the Ciona model system presents a simple scaffold that recapitulates the basic blueprint of cardiac development in Chordates. Here we will focus on the development and cellular structure of the heart of the ascidian Ciona as compared to other Chordates, principally vertebrates. Comparison of the Ciona model system to heart development in other Chordates presents great potential for dissecting the genetic mechanisms that underlie congenital heart defects and disease at the cellular level and might provide additional insight into potential pathways for therapeutic cardiac regeneration. PMID:27642586

  3. Cloning of ascidian homeobox genes provides evidence for a primordial chordate cluster.

    PubMed

    Di Gregorio, A; Spagnuolo, A; Ristoratore, F; Pischetola, M; Aniello, F; Branno, M; Cariello, L; Di Lauro, R

    1995-04-24

    In order to isolate genes important in controlling embryonic development in Tunicates, a genomic library from the ascidian Ciona intestinalis was screened with a degenerate oligodeoxyribonucleotide encoding the third helix of Antennapedia-type homeoboxes. Fourteen C. intestinalis homeobox genes, corresponding to several classes of homeodomains, have been identified. Five of the isolated homeoboxes show their highest homology to members of the Vertebrate HOX clusters. mRNAs for two of the isolated homeoboxes are present in unfertilized C. intestinalis eggs.

  4. Divergent mechanisms regulate conserved cardiopharyngeal development and gene expression in distantly related ascidians

    PubMed Central

    Stolfi, Alberto; Lowe, Elijah K; Racioppi, Claudia; Ristoratore, Filomena; Brown, C Titus; Swalla, Billie J; Christiaen, Lionel

    2014-01-01

    Ascidians present a striking dichotomy between conserved phenotypes and divergent genomes: embryonic cell lineages and gene expression patterns are conserved between distantly related species. Much research has focused on Ciona or Halocynthia spp. but development in other ascidians remains poorly characterized. In this study, we surveyed the multipotent myogenic B7.5 lineage in Molgula spp. Comparisons to the homologous lineage in Ciona revealed identical cell division and fate specification events that result in segregation of larval, cardiac, and pharyngeal muscle progenitors. Moreover, the expression patterns of key regulators are conserved, but cross-species transgenic assays uncovered incompatibility, or ‘unintelligibility’, of orthologous cis-regulatory sequences between Molgula and Ciona. These sequences drive identical expression patterns that are not recapitulated in cross-species assays. We show that this unintelligibility is likely due to changes in both cis- and trans-acting elements, hinting at widespread and frequent turnover of regulatory mechanisms underlying otherwise conserved aspects of ascidian embryogenesis. DOI: http://dx.doi.org/10.7554/eLife.03728.001 PMID:25209999

  5. A chemoattractant for ascidian spermatozoa is a sulfated steroid

    PubMed Central

    Yoshida, Manabu; Murata, Michio; Inaba, Kazuo; Morisawa, Masaaki

    2002-01-01

    Sperm chemotaxis toward eggs before fertilization has been demonstrated in many animals and plants, and several peptides and small organic compounds acting as chemoattractants have been identified. We previously showed that sperm of the ascidians Ciona intestinalis and Ciona savignyi are activated and then attracted toward the egg by a common factor released from the egg. In this study, we purified sperm-activating and -attracting factor (SAAF) from the egg-conditioning medium of C. intestinalis by using several steps of column chromatography. Determination of the molecular structure by NMR and MS/MS analysis revealed that SAAF is a previously uncharacterized sulfated steroid: 3,4,7,26-tetrahydroxycholestane-3,26-disulfate. Furthermore, it was shown that the SAAF of C. savignyi was indistinguishable from that of C. intestinalis in terms of the chromatographic behavior and molecular weight, indicating that the same compound might be responsible for sperm activation and chemotaxis in both the species. Furthermore, we established a method for quantitative analysis of sperm chemotaxis and showed that the chemotactic behavior of Ciona sperm is controlled by the “chemotactic turn” associated with decrease in the concentration of SAAF. PMID:12411583

  6. Metamorphosis in solitary ascidians.

    PubMed

    Karaiskou, Anthi; Swalla, Billie J; Sasakura, Yasunori; Chambon, Jean-Philippe

    2015-01-01

    Embryonic and postembryonic development in ascidians have been studied for over a century, but it is only in the last 10 years that the complex molecular network involved in coordinating postlarval development and metamorphosis has started to emerge. In most ascidians, the transition from the larval to the sessile juvenile/adult stage, or metamorphosis, requires a combination of environmental and endogenous signals and is characterized by coordinated global morphogenetic changes that are initiated by the adhesion of the larvae. Cloney was the first to describe cellular events of ascidians' metamorphosis in 1978 and only recently elements of the molecular regulation of this crucial developmental step have been revealed. This review aims to present a thorough view of this crucial developmental step by combining recent molecular data to the already established cellular events.

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

    PubMed

    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.

  8. Functional studies of the Ciona intestinalis myogenic regulatory factor reveal conserved features of chordate myogenesis.

    PubMed

    Izzi, Stephanie A; Colantuono, Bonnie J; Sullivan, Kelly; Khare, Parul; Meedel, Thomas H

    2013-04-15

    Ci-MRF is the sole myogenic regulatory factor (MRF) of the ascidian Ciona intestinalis, an invertebrate chordate. In order to investigate its properties we developed a simple in vivo assay based on misexpressing Ci-MRF in the notochord of Ciona embryos. We used this assay to examine the roles of three structural motifs that are conserved among MRFs: an alanine-threonine (Ala-Thr) dipeptide of the basic domain that is known in vertebrates as the myogenic code, a cysteine/histidine-rich (C/H) domain found just N-terminal to the basic domain, and a carboxy-terminal amphipathic α-helix referred to as Helix III. We show that the Ala-Thr dipeptide is necessary for normal Ci-MRF function, and that while eliminating the C/H domain or Helix III individually has no demonstrable effect on Ci-MRF, simultaneous loss of both motifs significantly reduces its activity. Our studies also indicate that direct interaction between CiMRF and an essential E-box of Ciona Troponin I is required for the expression of this muscle-specific gene and that multiple classes of MRF-regulated genes exist in Ciona. These findings are consistent with substantial conservation of MRF-directed myogenesis in chordates and demonstrate for the first time that the Ala/Thr dipeptide of the basic domain of an invertebrate MRF behaves as a myogenic code.

  9. The significance of Ciona intestinalis as a stem organism in integrative studies of functional evolution of the chordate endocrine, neuroendocrine, and nervous systems.

    PubMed

    Matsubara, Shin; Kawada, Tsuyoshi; Sakai, Tsubasa; Aoyama, Masato; Osugi, Tomohiro; Shiraishi, Akira; Satake, Honoo

    2016-02-01

    Ascidians are the closest phylogenetic neighbors to vertebrates and are believed to conserve the evolutionary origin in chordates of the endocrine, neuroendocrine, and nervous systems involving neuropeptides and peptide hormones. Ciona intestinalis harbors various homologs or prototypes of vertebrate neuropeptides and peptide hormones including gonadotropin-releasing hormones (GnRHs), tachykinins (TKs), and calcitonin, as well as Ciona-specific neuropeptides such as Ciona vasopressin, LF, and YFV/L peptides. Moreover, molecular and functional studies on Ciona tachykinin (Ci-TK) have revealed the novel molecular mechanism of inducing oocyte growth via up-regulation of vitellogenesis-associated protease activity, which is expected to be conserved in vertebrates. Furthermore, a series of studies on Ciona GnRH receptor paralogs have verified the species-specific regulation of GnRHergic signaling including unique signaling control via heterodimerization among multiple GnRH receptors. These findings confirm the remarkable significance of ascidians in investigations of the evolutionary processes of the peptidergic systems in chordates, leading to the promising advance in the research on Ciona peptides in the next stage based on the recent development of emerging technologies including genome-editing techniques, peptidomics-based multi-color staining, machine-learning prediction, and next-generation sequencing. These technologies and bioinformatic integration of the resultant "multi-omics" data will provide unprecedented insights into the comprehensive understanding of molecular and functional regulatory mechanisms of the Ciona peptides, and will eventually enable the exploration of both conserved and diversified endocrine, neuroendocrine, and nervous systems in the evolutionary lineage of chordates.

  10. Monoaminergic modulation of photoreception in ascidian: evidence for a proto-hypothalamo-retinal territory

    PubMed Central

    2012-01-01

    Background The retina of craniates/vertebrates has been proposed to derive from a photoreceptor prosencephalic territory in ancestral chordates, but the evolutionary origin of the different cell types making the retina is disputed. Except for photoreceptors, the existence of homologs of retinal cells remains uncertain outside vertebrates. Methods The expression of genes expressed in the sensory vesicle of the ascidian Ciona intestinalis including those encoding components of the monoaminergic neurotransmission systems, was analyzed by in situ hybridization or in vivo transfection of the corresponding regulatory elements driving fluorescent reporters. Modulation of photic responses by monoamines was studied by electrophysiology combined with pharmacological treatments. Results We show that many molecular characteristics of dopamine-synthesizing cells located in the vicinity of photoreceptors in the sensory vesicle of the ascidian Ciona intestinalis are similar to those of amacrine dopamine cells of the vertebrate retina. The ascidian dopamine cells share with vertebrate amacrine cells the expression of the key-transcription factor Ptf1a, as well as that of dopamine-synthesizing enzymes. Surprisingly, the ascidian dopamine cells accumulate serotonin via a functional serotonin transporter, as some amacrine cells also do. Moreover, dopamine cells located in the vicinity of the photoreceptors modulate the light-off induced swimming behavior of ascidian larvae by acting on alpha2-like receptors, instead of dopamine receptors, supporting a role in the modulation of the photic response. These cells are located in a territory of the ascidian sensory vesicle expressing genes found both in the retina and the hypothalamus of vertebrates (six3/6, Rx, meis, pax6, visual cycle proteins). Conclusion We propose that the dopamine cells of the ascidian larva derive from an ancestral multifunctional cell population located in the periventricular, photoreceptive field of the anterior

  11. ANISEED 2015: a digital framework for the comparative developmental biology of ascidians.

    PubMed

    Brozovic, Matija; Martin, Cyril; Dantec, Christelle; Dauga, Delphine; Mendez, Mickaël; Simion, Paul; Percher, Madeline; Laporte, Baptiste; Scornavacca, Céline; Di Gregorio, Anna; Fujiwara, Shigeki; Gineste, Mathieu; Lowe, Elijah K; Piette, Jacques; Racioppi, Claudia; Ristoratore, Filomena; Sasakura, Yasunori; Takatori, Naohito; Brown, Titus C; Delsuc, Frédéric; Douzery, Emmanuel; Gissi, Carmela; McDougall, Alex; Nishida, Hiroki; Sawada, Hitoshi; Swalla, Billie J; Yasuo, Hitoyoshi; Lemaire, Patrick

    2016-01-04

    Ascidians belong to the tunicates, the sister group of vertebrates and are recognized model organisms in the field of embryonic development, regeneration and stem cells. ANISEED is the main information system in the field of ascidian developmental biology. This article reports the development of the system since its initial publication in 2010. Over the past five years, we refactored the system from an initial custom schema to an extended version of the Chado schema and redesigned all user and back end interfaces. This new architecture was used to improve and enrich the description of Ciona intestinalis embryonic development, based on an improved genome assembly and gene model set, refined functional gene annotation, and anatomical ontologies, and a new collection of full ORF cDNAs. The genomes of nine ascidian species have been sequenced since the release of the C. intestinalis genome. In ANISEED 2015, all nine new ascidian species can be explored via dedicated genome browsers, and searched by Blast. In addition, ANISEED provides full functional gene annotation, anatomical ontologies and some gene expression data for the six species with highest quality genomes. ANISEED is publicly available at: http://www.aniseed.cnrs.fr.

  12. ANISEED 2015: a digital framework for the comparative developmental biology of ascidians

    PubMed Central

    Brozovic, Matija; Martin, Cyril; Dantec, Christelle; Dauga, Delphine; Mendez, Mickaël; Simion, Paul; Percher, Madeline; Laporte, Baptiste; Scornavacca, Céline; Di Gregorio, Anna; Fujiwara, Shigeki; Gineste, Mathieu; Lowe, Elijah K.; Piette, Jacques; Racioppi, Claudia; Ristoratore, Filomena; Sasakura, Yasunori; Takatori, Naohito; Brown, Titus C.; Delsuc, Frédéric; Douzery, Emmanuel; Gissi, Carmela; McDougall, Alex; Nishida, Hiroki; Sawada, Hitoshi; Swalla, Billie J.; Yasuo, Hitoyoshi; Lemaire, Patrick

    2016-01-01

    Ascidians belong to the tunicates, the sister group of vertebrates and are recognized model organisms in the field of embryonic development, regeneration and stem cells. ANISEED is the main information system in the field of ascidian developmental biology. This article reports the development of the system since its initial publication in 2010. Over the past five years, we refactored the system from an initial custom schema to an extended version of the Chado schema and redesigned all user and back end interfaces. This new architecture was used to improve and enrich the description of Ciona intestinalis embryonic development, based on an improved genome assembly and gene model set, refined functional gene annotation, and anatomical ontologies, and a new collection of full ORF cDNAs. The genomes of nine ascidian species have been sequenced since the release of the C. intestinalis genome. In ANISEED 2015, all nine new ascidian species can be explored via dedicated genome browsers, and searched by Blast. In addition, ANISEED provides full functional gene annotation, anatomical ontologies and some gene expression data for the six species with highest quality genomes. ANISEED is publicly available at: http://www.aniseed.cnrs.fr. PMID:26420834

  13. Expression of a single prominin homolog in the embryo of the model chordate Ciona intestinalis.

    PubMed

    Russo, Monia T; Racioppi, Claudia; Zanetti, Laura; Ristoratore, Filomena

    2014-05-01

    Prominins are a family of pentaspan transmembrane glycoproteins, expressed in various types of cells, including stem and cancer stem cells in mammals. Prominin-1 is critical in generating and maintaining the structure of the photoreceptors in the eye since mutations in the PROM1 gene are associated with retinal and macular degeneration in human. In this study, we identified a single prominin homolog, Ci-prom1/2, in the model chordate the ascidian Ciona intestinalis and characterized Ci-prom1/2 expression profile in relation to photoreceptor differentiation during Ciona embryonic development. In situ hybridization experiments show Ci-prom1/2 transcripts localized in the developing central nervous system, predominantly in photoreceptor cell precursors as early as neurula stage and expression is maintained through larva stage in photoreceptor cells around the simple eye. We also isolated the regulatory region responsible for the specific spatio-temporal expression of the Ci-prom1/2 in photoreceptor cell lineage. Collectively, we report that Ci-prom1/2 is a novel molecular marker for ascidian photoreceptor cells and might represent a potential source to enlarge the knowledge about the function of prominin family in photoreceptor cell evolution and development.

  14. Evolutionary origins of the vertebrate heart: Specification of the cardiac lineage in Ciona intestinalis

    PubMed Central

    Davidson, Brad; Levine, Michael

    2003-01-01

    Here we exploit the extensive cell lineage information and streamlined genome of the ascidian, Ciona intestinalis, to investigate heart development in a basal chordate. Several cardiac genes were analyzed, including the sole Ciona ortholog of the Drosophila tinman gene, and tissue-specific enhancers were isolated for some of the genes. Conserved sequence motifs within these enhancers facilitated the isolation of a heart enhancer for the Ciona Hand-like gene. Altogether, these studies provide a regulatory framework for the differentiation of the cardiac mesoderm, beginning at the 110-cell stage, and extending through the fusion of cardiac progenitors during tail elongation. The cardiac lineage shares a common origin with the germ line, and zygotic transcription is first detected in the heart progenitors only after its separation from the germ line at the 64-cell stage. We propose that germ-line determinants influence the specification of the cardiac mesoderm, both by inhibiting inductive signals required for the development of noncardiac mesoderm lineages, and by providing a localized source of Wnt-5 and other signals required for heart development. We discuss the possibility that the germ line also influences the specification of the vertebrate heart. PMID:14500781

  15. Ordered expression pattern of Hox and ParaHox genes along the alimentary canal in the ascidian juvenile.

    PubMed

    Nakayama, Satoshi; Satou, Kunihiro; Orito, Wataru; Ogasawara, Michio

    2016-07-01

    The Hox and ParaHox genes of bilateria share a similar expression pattern along the body axis and are known to be associated with anterior-posterior patterning. In vertebrates, the Hox genes are also expressed in presomitic mesoderm and gut endoderm and the ParaHox genes show a restricted expression pattern in the gut-related derivatives. Regional expression patterns in the embryonic central nervous system of the basal chordates amphioxus and ascidian have been reported; however, little is known about their endodermal expression in the alimentary canal. We focus on the Hox and ParaHox genes in the ascidian Ciona intestinalis and investigate the gene expression patterns in the juvenile, which shows morphological regionality in the alimentary canal. Gene expression analyses by using whole-mount in situ hybridization reveal that all Hox genes have a regional expression pattern along the alimentary canal. Expression of Hox1 to Hox4 is restricted to the posterior region of pharyngeal derivatives. Hox5 to Hox13 show an ordered expression pattern correlated with each Hox gene number along the postpharyngeal digestive tract. This expression pattern along the anterior-posterior axis has also been observed in Ciona ParaHox genes. Our observations suggest that ascidian Hox and ParaHox clusters are dispersed; however, the ordered expression patterns along the alimentary canal appear to be conserved among chordates.

  16. Transcriptional regulation of the peripheral nervous system in Ciona intestinalis.

    PubMed

    Joyce Tang, W; Chen, Jerry S; Zeller, Robert W

    2013-06-15

    The formation of the sensory organs and cells that make up the peripheral nervous system (PNS) relies on the activity of transcription factors encoded by proneural genes (PNGs). Although PNGs have been identified in the nervous systems of both vertebrates and invertebrates, the complexity of their interactions has complicated efforts to understand their function in the context of their underlying regulatory networks. To gain insight into the regulatory network of PNG activity in chordates, we investigated the roles played by PNG homologs in regulating PNS development of the invertebrate chordate Ciona intestinalis. We discovered that in Ciona, MyT1, Pou4, Atonal, and NeuroD-like are expressed in a sequential regulatory cascade in the developing epidermal sensory neurons (ESNs) of the PNS and act downstream of Notch signaling, which negatively regulates these genes and the number of ESNs along the tail midlines. Transgenic embryos mis-expressing any of these proneural genes in the epidermis produced ectopic midline ESNs. In transgenic embryos mis-expressing Pou4, and MyT1 to a lesser extent, numerous ESNs were produced outside of the embryonic midlines. In addition we found that the microRNA miR-124, which inhibits Notch signaling in ESNs, is activated downstream of all the proneural factors we tested, suggesting that these genes operate collectively in a regulatory network. Interestingly, these factors are encoded by the same genes that have recently been demonstrated to convert fibroblasts into neurons. Our findings suggest the ascidian PNS can serve as an in vivo model to study the underlying regulatory mechanisms that enable the conversion of cells into sensory neurons.

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

    PubMed

    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.

  18. Screening of ovarian steroidogenic pathway in Ciona intestinalis and its modulation after tributyltin exposure.

    PubMed

    Cangialosi, Maria Vittoria; Puccia, Egidio; Mazzola, Antonio; Mansueto, Valentina; Arukwe, Augustine

    2010-05-15

    In this study, we have identified several ovarian steroids in Ciona with high similarity to vertebrate steroids and showed that cholesterol, corticosterone, dehydroepiandrosterone, estrone, estradiol-17beta, testosterone, pregnenolone, progesterone, have identical molecular spectra with vertebrate steroids. In addition, we have studied the effects of an endocrine disruptor (tributyltin: TBT) on these sex hormones and their precursors, ovarian morphology, and gene expression of some key enzymes in steroidogenic pathway in the ovary of Ciona. Ovarian specimens were cultured in vitro using different concentrations of TBT (10(-5), 10(-4) and 10(-3)M). Ethanol was used as solvent control. Gene expression analysis was performed for adrenodoxin (ADREN) and adrenodoxin reductase (ADOX) (mediators of acute steroidogenesis) and 17beta-hydroxysteroid dehydrogenase (17beta-HSD). These transcripts were detected and measured by quantitative (real-time) polymerase chain reaction (qPCR). Sex steroids and their precursors were identified and quantified by a gas chromatography-mass spectroscopy (GC-MS) method. Exposure of Ciona ovaries to TBT produced modulations (either increased or decreased) of sterols and sex steroid levels, whereas no significant differences in ADREN, ADOX or 17beta-HSD mRNA expression patterns were observed. Histological analysis shows that TBT produced several modifications on Ciona ovarian morphology that includes irregular outline of nuclear membrane, less compacted cytoplasm, in addition to test and granulosa cells that were detached from the oocyte membrane. Given that the ascidians represent very simple experimental models for the study of endocrine disruption by environmental contaminants, our findings provide excellent models for multiple identification and quantification of sex steroid and their precursors in biological samples exposed to endocrine-disrupting chemicals and for direct extrapolation of such effects across taxonomic groups and phyla. In

  19. Screening of ovarian steroidogenic pathway in Ciona intestinalis and its modulation after tributyltin exposure

    SciTech Connect

    Cangialosi, Maria Vittoria; Puccia, Egidio; Mazzola, Antonio; Mansueto, Valentina; Arukwe, Augustine

    2010-05-15

    In this study, we have identified several ovarian steroids in Ciona with high similarity to vertebrate steroids and showed that cholesterol, corticosterone, dehydroepiandrosterone, estrone, estradiol-17beta, testosterone, pregnenolone, progesterone, have identical molecular spectra with vertebrate steroids. In addition, we have studied the effects of an endocrine disruptor (tributyltin: TBT) on these sex hormones and their precursors, ovarian morphology, and gene expression of some key enzymes in steroidogenic pathway in the ovary of Ciona. Ovarian specimens were cultured in vitro using different concentrations of TBT (10{sup -5}, 10{sup -4} and 10{sup -3} M). Ethanol was used as solvent control. Gene expression analysis was performed for adrenodoxin (ADREN) and adrenodoxin reductase (ADOX) (mediators of acute steroidogenesis) and 17beta-hydroxysteroid dehydrogenase (17beta-HSD). These transcripts were detected and measured by quantitative (real-time) polymerase chain reaction (qPCR). Sex steroids and their precursors were identified and quantified by a gas chromatography-mass spectroscopy (GC-MS) method. Exposure of Ciona ovaries to TBT produced modulations (either increased or decreased) of sterols and sex steroid levels, whereas no significant differences in ADREN, ADOX or 17beta-HSD mRNA expression patterns were observed. Histological analysis shows that TBT produced several modifications on Ciona ovarian morphology that includes irregular outline of nuclear membrane, less compacted cytoplasm, in addition to test and granulosa cells that were detached from the oocyte membrane. Given that the ascidians represent very simple experimental models for the study of endocrine disruption by environmental contaminants, our findings provide excellent models for multiple identification and quantification of sex steroid and their precursors in biological samples exposed to endocrine-disrupting chemicals and for direct extrapolation of such effects across taxonomic groups

  20. The Ciona intestinalis genome: when the constraints are off

    NASA Technical Reports Server (NTRS)

    Holland, Linda Z.; Gibson-Brown, Jeremy J.

    2003-01-01

    The recent genome sequencing of a non-vertebrate deuterostome, the ascidian tunicate Ciona intestinalis, makes a substantial contribution to the fields of evolutionary and developmental biology.1 Tunicates have some of the smallest bilaterian genomes, embryos with relatively few cells, fixed lineages and early determination of cell fates. Initial analyses of the C. intestinalis genome indicate that it has been evolving rapidly. Comparisons with other bilaterians show that C. intestinalis has lost a number of genes, and that many genes linked together in most other bilaterians have become uncoupled. In addition, a number of independent, lineage-specific gene duplications have been detected. These new results, although interesting in themselves, will take on a deeper significance once the genomes of additional invertebrate deuterostomes (e.g. echinoderms, hemichordates and amphioxus) have been sequenced. With such a broadened database, comparative genomics can begin to ask pointed questions about the relationship between the evolution of genomes and the evolution of body plans. Copyright 2003 Wiley Periodicals, Inc.

  1. Fgf genes in the basal chordate Ciona intestinalis.

    PubMed

    Satou, Yutaka; Imai, Kaoru S; Satoh, Nori

    2002-10-01

    In vertebrates, a number of fibroblast growth factors (FGFs) have been shown to play important roles in developing embryos and adult organisms. However, the molecular relationships of the vertebrate FGFs are not yet completely understood, partly due to the divergence of their amino acid sequences. To solve this problem, we have identified six FGF genes in a basal chordate, the ascidian Ciona intestinalis. A phylogenetic analysis confidently assigned two of them to vertebrate FGF8/17/18 and FGF11/12/13/14, respectively. Based on the presence of the conserved domains within or outside of the FGF domains, we speculate that three of the other genes are orthologous to vertebrate FGF3/7/10/22, FGF4/5/6 and FGF9/16/20, respectively, although we cannot assign the sixth member to any of the vertebrate FGFs. A survey of the raw whole genome shotgun sequences of C. intestinalis demonstrated the presence of no FGF genes other than the six genes in the genome. The identification of these six FGF genes in the basal chordate gave us an insight into the diversification of specific subfamilies of vertebrate FGFs.

  2. Temporal stability of bacterial symbionts in a temperate ascidian

    PubMed Central

    López-Legentil, Susanna; Turon, Xavier; Espluga, Roger; Erwin, Patrick M.

    2015-01-01

    In temperate seas, both bacterioplankton communities and invertebrate lifecycles follow a seasonal pattern. To investigate whether the bacterial community associated with the Mediterranean ascidian Didemnum fulgens exhibited similar variations, we monitored its bacterial community structure monthly for over a year using terminal restriction fragment length polymorphism and clone library analyses based on a nearly full length fragment of the 16S rRNA gene. D. fulgens harbored a bacterial consortium typical of ascidians, including numerous members of the phylum Proteobacteria, and a few members of the phyla Cyanobacteria and Acidobacteria. The overall bacterial community in D. fulgens had a distinct signature from the surrounding seawater and was stable over time and across seasonal fluctuations in temperature. Bacterial symbionts were also observed around animal cells in the tunic of adult individuals and in the inner tunic of D. fulgens larvae by transmission electron microscopy. Our results suggest that, as seen for sponges and corals, some species of ascidians host stable and unique bacterial communities that are at least partially inherited by their progeny by vertical transmission. PMID:26441944

  3. 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.

    PubMed

    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.

  4. Identification of a retinoic acid-responsive neural enhancer in the Ciona intestinalis Hox1 gene.

    PubMed

    Kanda, Miyuki; Ikeda, Taku; Fujiwara, Shigeki

    2013-02-01

    The Hox1 gene in the urochordate ascidian Ciona intestinalis (Ci-Hox1) is expressed in the nerve cord and epidermis. We identified a nerve cord enhancer in the second intron of Ci-Hox1, and demonstrated that retinoic acid (RA) plays a major role in activating this enhancer. The enhancer contained a putative retinoic acid-response element (RARE). Mutation of the RARE in the Ci-Hox1 nerve cord enhancer only partially abolished the enhancer activity. Genes encoding RA synthase and the RA receptor were knocked down using specific antisense morpholino oligos (MOs), and injection of embryos with these MOs resulted in the complete disappearance of epidermal expression of Ci-Hox1 and reduction of neural expression. However, nerve cord expression was not completely repressed. These results suggest that the nerve cord enhancer is activated by two partially redundant pathways; one RA-dependent and one RA-independent.

  5. Ciona intestinalis interleukin 17-like genes expression is upregulated by LPS challenge.

    PubMed

    Vizzini, Aiti; Di Falco, Felicia; Parrinello, Daniela; Sanfratello, Maria Antonietta; Mazzarella, Claudia; Parrinello, Nicolò; Cammarata, Matteo

    2015-01-01

    In humans, IL-17 is a proinflammatory cytokine that plays a key role in the clearance of extracellular bacteria promoting cell infiltration and production of several cytokines and chemokines. Here, we report on three Ciona intestinalis IL-17 homologues (CiIL17-1, CiIL17-2, CiIL17-3). The gene organization, phylogenetic tree and modeling supported the close relationship with the mammalian IL-17A and IL-17F suggesting that the C. intestinalis IL-17 genes share a common ancestor in the chordate lineages. Real time PCR analysis showed a prompt expression induced by LPS inoculation suggesting that they are involved in the first phase of inflammatory response. In situ hybridization assays disclosed that the genes transcription was upregulated in the pharynx, the main organ of the ascidian immune system, and expressed by hemocytes (granulocytes and univacuolar refractile granulocyte) inside the pharynx vessels.

  6. Genetic signatures of natural selection in a model invasive ascidian

    NASA Astrophysics Data System (ADS)

    Lin, Yaping; Chen, Yiyong; Yi, Changho; Fong, Jonathan J.; Kim, Won; Rius, Marc; Zhan, Aibin

    2017-03-01

    Invasive species represent promising models to study species’ responses to rapidly changing environments. Although local adaptation frequently occurs during contemporary range expansion, the associated genetic signatures at both population and genomic levels remain largely unknown. Here, we use genome-wide gene-associated microsatellites to investigate genetic signatures of natural selection in a model invasive ascidian, Ciona robusta. Population genetic analyses of 150 individuals sampled in Korea, New Zealand, South Africa and Spain showed significant genetic differentiation among populations. Based on outlier tests, we found high incidence of signatures of directional selection at 19 loci. Hitchhiking mapping analyses identified 12 directional selective sweep regions, and all selective sweep windows on chromosomes were narrow (~8.9 kb). Further analyses indentified 132 candidate genes under selection. When we compared our genetic data and six crucial environmental variables, 16 putatively selected loci showed significant correlation with these environmental variables. This suggests that the local environmental conditions have left significant signatures of selection at both population and genomic levels. Finally, we identified “plastic” genomic regions and genes that are promising regions to investigate evolutionary responses to rapid environmental change in C. robusta.

  7. Genetic signatures of natural selection in a model invasive ascidian

    PubMed Central

    Lin, Yaping; Chen, Yiyong; Yi, Changho; Fong, Jonathan J.; Kim, Won; Rius, Marc; Zhan, Aibin

    2017-01-01

    Invasive species represent promising models to study species’ responses to rapidly changing environments. Although local adaptation frequently occurs during contemporary range expansion, the associated genetic signatures at both population and genomic levels remain largely unknown. Here, we use genome-wide gene-associated microsatellites to investigate genetic signatures of natural selection in a model invasive ascidian, Ciona robusta. Population genetic analyses of 150 individuals sampled in Korea, New Zealand, South Africa and Spain showed significant genetic differentiation among populations. Based on outlier tests, we found high incidence of signatures of directional selection at 19 loci. Hitchhiking mapping analyses identified 12 directional selective sweep regions, and all selective sweep windows on chromosomes were narrow (~8.9 kb). Further analyses indentified 132 candidate genes under selection. When we compared our genetic data and six crucial environmental variables, 16 putatively selected loci showed significant correlation with these environmental variables. This suggests that the local environmental conditions have left significant signatures of selection at both population and genomic levels. Finally, we identified “plastic” genomic regions and genes that are promising regions to investigate evolutionary responses to rapid environmental change in C. robusta. PMID:28266616

  8. Three-dimensional anatomy of the Ciona intestinalis tailbud embryo at single-cell resolution.

    PubMed

    Nakamura, Mitsuru J; Terai, Jun; Okubo, Reiko; Hotta, Kohji; Oka, Kotaro

    2012-12-15

    During embryogenesis, chordates pass through a tailbud stage in which the larval tail is formed. Since acquisition of a tadpole-like tail during tailbud stage is one of the key events in the evolution of chordates, understanding the anatomy of the tailbud stage chordate embryo is of special interest. In this study, to understand comprehensively the anatomy of the tailbud embryo at single-cell-level, real microscopic image stacks of the tailbud embryo in Ciona intestinalis were reconstructed into a 3D computer model. This comprehensive 3D model of the ascidian tailbud embryo was based on real images of confocal laser scanning microscope (CLSM) and therefore, cell shape, location and cell arrangement reflect real geometries of the tailbud embryo. We found that the tailbud embryo consists of 1579 cells, including 836 epidermal cells, 228 cells in the central nervous system, 218 mesenchymal cells, four trunk ventral cells, two B/B(⁎)8.11 cells, 36 muscle cells, 40 notochord cells, four primordial germ cells, and 199 endodermal cells. Moreover, we identified for the first time two populations of previously undefined cells (a total of 12 cells) in Ciona: one located in the lateral trunk and the other located under the tail dorsal epidermis. This information provides a first step for understanding how the body plan of the chordate tailbud embryo formed and evolved.

  9. A transiently expressed connexin is essential for anterior neural plate development in Ciona intestinalis.

    PubMed

    Hackley, Christopher; Mulholland, Erin; Kim, Gil Jung; Newman-Smith, Erin; Smith, William C

    2013-01-01

    A forward genetic screen in the ascidian Ciona intestinalis identified a mutant line (frimousse) with a profound disruption in neural plate development. In embryos with the frimousse mutation, the anteriormost neural plate cells, which are products of an FGF induction at the blastula and gastrula stages, initially express neural plate-specific genes but fail to maintain the induced state and ultimately default to epidermis. The genetic lesion in the frimousse mutant lies within a connexin gene (cx-11) that is transiently expressed in the developing neural plate in a temporal window corresponding to the period of a-lineage neural induction. Using a genetically encoded calcium indicator we observed multiple calcium transients throughout the developing neural plate in wild-type embryos, but not in mutant embryos. A series of treatments at the gastrula and neurula stages that block the calcium transients, including gap junction inhibition and calcium depletion, were also found to disrupt the development of the anterior neural plate in a similar way to the frimousse mutation. The requirement for cx-11 for anterior neural fate points to a crucial role for intercellular communication via gap junctions, probably through mediation of Ca(2+) transients, in Ciona intestinalis neural induction.

  10. Porcine relaxin, a 500 million-year-old hormone? the tunicate Ciona intestinalis has porcine relaxin.

    PubMed

    Georges, D; Schwabe, C

    1999-07-01

    The fossil record of tunicates reaches back to the upper Cambrian period. Ascidians have mobile, tadpole-like juvenile forms with a notochord, which inspired the classification of tunicates as Urochordata, i.e., predecessors of vertebrates. The genome of the tunicate Ciona intestinalis contains a relaxin coding region that is organized like a mammalian gene, i.e., signal peptide, B-chain domain, connecting peptide domain, followed by the A-chain domain with a stop codon after cysteine A-22. RNA-derived cDNA encodes a relaxin that is identical to the circulating form of the porcine hormone. In contrast to the porcine gene, the ascidian gene has no intron in the C-peptide domain, and in that respect is similar to the bombyxin gene of the silkworm. During the spawning period, only enough relaxin could be extracted and isolated from gonads of C. intestinalis for a partial sequence analysis. Remarkable as it may be, these findings suggest that relaxin is identical in pigs, whales, and the tunicate C. intestinalis.

  11. A standardisation of Ciona intestinalis (Chordata, Ascidiacea) embryo-larval bioassay for ecotoxicological studies.

    PubMed

    Bellas, Juan; Beiras, Ricardo; Vázquez, Elsa

    2003-11-01

    A standardisation of the ascidian Ciona intestinalis embryo-larval bioassay for marine pollution assessment has been developed. The minimum percentage of embryogenesis success was established to assess the quality of the biological material used; minimum sample size and number of replicates per treatment were also estimated. The suitability of artificial and natural seawater for the incubation of ascidian embryos and larvae was compared, and the optimum conditions of temperature, salinity, pH, density of embryos in the vials and the sperm/egg ratio were investigated. On the basis of the 10th percentile of the distribution of larval abnormalities, we proposed a threshold of 50% normal larvae in the control in order to consider the test of acceptable biological quality. According to our results n=5 is a sufficiently high replication to detect 5% differences among treatment means with a power of P=90% and alpha=0.05, and a sampling size >/=222 allows a 95% confidence in the estimate with an error of 0.05. Egg density did not affect larval development within the range 1-20 eggs/ml, and the optimum sperm/egg ratio which fertilise 100% of the eggs was 3000-30,000 sperm/egg (i.e. 10(8)-10(7) sperm/ml). There were not significant differences between the two water types tested, and the optimum tolerance ranges were 18-23 degrees C temperature, 34-42 ppt salinity (42 ppt was the highest salinity tested), and 7.4-8.8 pH. The median effective concentration (EC(50)) of copper (Cu) causing a 50% reduction of normal hatched larvae was 54.2 microg/l (0.85 microM), which shows a sensitivity of this species similar to the commonly used bivalve and sea-urchin tests. The ascidian embryo-larval bioassay is an accurate, reliable, simple and rapid method that can be used in ecotoxicological studies.

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

    PubMed

    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.

  13. Transcript Mapping and Genome Annotation of Ascidian mtDNA Using EST Data

    PubMed Central

    Gissi, Carmela; Pesole, Graziano

    2003-01-01

    Mitochondrial transcripts of two ascidian species were reconstructed through sequence assembly of publicly available ESTs resembling mitochondrial DNA sequences (mt-ESTs). This strategy allowed us to analyze processing and mapping of the mitochondrial transcripts and to investigate the gene organization of a previously uncharacterized mitochondrial genome (mtDNA). This new strategy would greatly facilitate the sequencing and annotation of mtDNAs. In Ciona intestinalis, the assembled mt-ESTs covered 22 mitochondrial genes (∼12,000 bp) and provided the partial sequence of the mtDNA and the prediction of its gene organization. Such sequences were confirmed by amplification and sequencing of the entire Ciona mtDNA. For Halocynthia roretzi, for which the mtDNA sequence was already available, the inferred mt transcripts allowed better definition of gene boundaries (16S rRNA, ND1, ATP6, and tRNA-Ser genes) and the identification of a new gene (an additional Phe-tRNA). In both species, polycistronic and immature transcripts, creation of stop codons by polyadenylation, tRNA signal processing, and rRNA transcript termination signals were identified, thus suggesting that the main features of mitochondrial transcripts are conserved in Chordata. PMID:12915488

  14. Ciona intestinalis as an emerging model organism: its regeneration under controlled conditions and methodology for egg dechorionation.

    PubMed

    Liu, Li-ping; Xiang, Jian-hai; Dong, Bo; Natarajan, Pavanasam; Yu, Kui-jie; Cai, Nan-er

    2006-06-01

    The ascidian Ciona intestinalis is a model organism of developmental and evolutionary biology and may provide crucial clues concerning two fundamental matters, namely, how chordates originated from the putative deuterostome ancestor and how advanced chordates originated from the simplest chordates. In this paper, a whole-life-span culture of C. intestinalis was conducted. Fed with the diet combination of dry Spirulina, egg yolk, Dicrateria sp., edible yeast and weaning diet for shrimp, C. intestinalis grew up to average 59 mm and matured after 60 d cultivation. This culture process could be repeated using the artificially cultured mature ascidians as material. When the fertilized eggs were maintained under 10, 15, 20, 25 degrees C, they hatched within 30 h, 22 h, 16 h and 12 h 50 min respectively experiencing cleavage, blastulation, gastrulation, neurulation, tailbud stage and tadpole stage. The tadpole larvae were characterized as typical but simplified chordates because of their dorsal nerve cord, notochord and primordial brain. After 8 - 24 h freely swimming, the tadpole larvae settled on the substrates and metamorphosized within 1- 2 d into filter feeding sessile juvenile ascidians. In addition, unfertilized eggs were successfully dechorionated in filtered seawater containing 1% Tripsin, 0.25% EDTA at pH of 10.5 within 40 min. After fertilization, the dechorionated eggs developed well and hatched at normal hatching rate. In conclusion, this paper presented feasible methodology for rearing the tadpole larvae of C. intestinalis into sexual maturity under controlled conditions and detailed observations on the embryogenesis of the laboratory cultured ascidians, which will facilitate developmental and genetic research using this model system.

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

    PubMed

    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.

  16. Ascidian Mitogenomics: Comparison of Evolutionary Rates in Closely Related Taxa Provides Evidence of Ongoing Speciation Events

    PubMed Central

    Griggio, Francesca; Voskoboynik, Ayelet; Iannelli, Fabio; Justy, Fabienne; Tilak, Marie-Ka; Xavier, Turon; Pesole, Graziano; Douzery, Emmanuel J.P.; Mastrototaro, Francesco; Gissi, Carmela

    2014-01-01

    Ascidians are a fascinating group of filter-feeding marine chordates characterized by rapid evolution of both sequences and structure of their nuclear and mitochondrial genomes. Moreover, they include several model organisms used to investigate complex biological processes in chordates. To study the evolutionary dynamics of ascidians at short phylogenetic distances, we sequenced 13 new mitogenomes and analyzed them, together with 15 other available mitogenomes, using a novel approach involving detailed whole-mitogenome comparisons of conspecific and congeneric pairs. The evolutionary rate was quite homogeneous at both intraspecific and congeneric level, and the lowest congeneric rates were found in cryptic (morphologically undistinguishable) and in morphologically very similar species pairs. Moreover, congeneric nonsynonymous rates (dN) were up to two orders of magnitude higher than in intraspecies pairs. Overall, a clear-cut gap sets apart conspecific from congeneric pairs. These evolutionary peculiarities allowed easily identifying an extraordinary intraspecific variability in the model ascidian Botryllus schlosseri, where most pairs show a dN value between that observed at intraspecies and congeneric level, yet consistently lower than that of the Ciona intestinalis cryptic species pair. These data suggest ongoing speciation events producing genetically distinct B. schlosseri entities. Remarkably, these ongoing speciation events were undetectable by the cox1 barcode fragment, demonstrating that, at low phylogenetic distances, the whole mitogenome has a higher resolving power than cox1. Our study shows that whole-mitogenome comparative analyses, performed on a suitable sample of congeneric and intraspecies pairs, may allow detecting not only cryptic species but also ongoing speciation events. PMID:24572017

  17. The CNS connectome of a tadpole larva of Ciona intestinalis (L.) highlights sidedness in the brain of a chordate sibling.

    PubMed

    Ryan, Kerrianne; Lu, Zhiyuan; Meinertzhagen, Ian A

    2016-12-06

    Left-right asymmetries in brains are usually minor or cryptic. We report brain asymmetries in the tiny, dorsal tubular nervous system of the ascidian tadpole larva, Ciona intestinalis. Chordate in body plan and development, the larva provides an outstanding example of brain asymmetry. Although early neural development is well studied, detailed cellular organization of the swimming larva's CNS remains unreported. Using serial-section EM we document the synaptic connectome of the larva's 177 CNS neurons. These formed 6618 synapses including 1772 neuromuscular junctions, augmented by 1206 gap junctions. Neurons are unipolar with at most a single dendrite, and few synapses. Some synapses are unpolarised, others form reciprocal or serial motifs; 922 were polyadic. Axo-axonal synapses predominate. Most neurons have ciliary organelles, and many features lack structural specialization. Despite equal cell numbers on both sides, neuron identities and pathways differ left/right. Brain vesicle asymmetries include a right ocellus and left coronet cells.

  18. Upregulated transcription of phenoloxidase genes in the pharynx and endostyle of Ciona intestinalis in response to LPS.

    PubMed

    Vizzini, Aiti; Parrinello, Daniela; Sanfratello, Maria Antonietta; Trapani, Maria Rosa; Mangano, Valentina; Parrinello, Nicolò; Cammarata, Matteo

    2015-03-01

    We investigated the role of phenoloxidases (POs) in ascidians inflammatory reaction, a components of a copper-containing protein family involved in invertebrate immune system. In Ciona intestinalis two phenoloxidases (CinPO-1, CinPO-2) have been sequenced. In the present study, real time PCR analysis showed that both CinPO-1 and CinPO-2 genes were modulated by LPS inoculation suggesting that they are inducible and highly expressed in the inflamed pharynx. In situ hybridization disclosed CinPO-1 and CinPO-2 transcripts in pharynx hemocytes (granulocytes) and, mainly, in unilocular refractile granulocytes (URG) which mainly populated the inflamed tunic matrix. Interestingly, the genes are also upregulated by LPS in the endostyle (zones 7, 8 and 9) that is considered homolog to the vertebrate thyroid.

  19. Enhancer of zeste acts as a major developmental regulator of Ciona intestinalis embryogenesis.

    PubMed

    Le Goff, Emilie; Martinand-Mari, Camille; Martin, Marianne; Feuillard, Jérôme; Boublik, Yvan; Godefroy, Nelly; Mangeat, Paul; Baghdiguian, Stephen; Cavalli, Giacomo

    2015-08-14

    The paradigm of developmental regulation by Polycomb group (PcG) proteins posits that they maintain silencing outside the spatial expression domains of their target genes, particularly of Hox genes, starting from mid embryogenesis. The Enhancer of zeste [E(z)] PcG protein is the catalytic subunit of the PRC2 complex, which silences its targets via deposition of the H3K27me3 mark. Here, we studied the ascidian Ciona intestinalis counterpart of E(z). Ci-E(z) is detected by immunohistochemistry as soon as the 2- and 4-cell stages as a cytoplasmic form and becomes exclusively nuclear thereafter, whereas the H3K27me3 mark is detected starting from the gastrula stage and later. Morpholino invalidation of Ci-E(z) leads to the total disappearance of both Ci-E(z) protein and its H3K27me3 mark. Ci-E(z) morphants display a severe phenotype. Strikingly, the earliest defects occur at the 4-cell stage with the dysregulation of cell positioning and mitotic impairment. At later stages, Ci-E(z)-deficient embryos are affected by terminal differentiation defects of neural, epidermal and muscle tissues, by the failure to form a notochord and by the absence of caudal nerve. These major phenotypic defects are specifically rescued by injection of a morpholino-resistant Ci-E(z) mRNA, which restores expression of Ci-E(z) protein and re-deposition of the H3K27me3 mark. As observed by qPCR analyses, Ci-E(z) invalidation leads to the early derepression of tissue-specific developmental genes, whereas late-acting developmental genes are generally down-regulated. Altogether, our results suggest that Ci-E(z) plays a major role during embryonic development in Ciona intestinalis by silencing early-acting developmental genes in a Hox-independent manner.

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

    PubMed

    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.

  1. miR-124 function during Ciona intestinalis neuronal development includes extensive interaction with the Notch signaling pathway.

    PubMed

    Chen, Jerry S; Pedro, Matthew San; Zeller, Robert W

    2011-11-01

    The nervous system-enriched microRNA miR-124 is necessary for proper nervous system development, although the mechanism remains poorly understood. Here, through a comprehensive analysis of miR-124 and its gene targets, we demonstrate that, in the chordate ascidian Ciona intestinalis, miR-124 plays an extensive role in promoting nervous system development. We discovered that feedback interaction between miR-124 and Notch signaling regulates the epidermal-peripheral nervous system (PNS) fate choice in tail midline cells. Notch signaling silences miR-124 in epidermal midline cells, whereas in PNS midline cells miR-124 silences Notch, Neuralized and all three Ciona Hairy/Enhancer-of-Split genes. Furthermore, ectopic expression of miR-124 is sufficient to convert epidermal midline cells into PNS neurons, consistent with a role in modulating Notch signaling. More broadly, genome-wide target extraction with validation using an in vivo tissue-specific sensor assay indicates that miR-124 shapes neuronal progenitor fields by downregulating non-neural genes, notably the muscle specifier Macho-1 and 50 Brachyury-regulated notochord genes, as well as several anti-neural factors including SCP1 and PTBP1. 3'UTR conservation analysis reveals that miR-124 targeting of SCP1 is likely to have arisen as a shared, derived trait in the vertebrate/tunicate ancestor and targeting of PTBP1 is conserved among bilaterians except for ecdysozoans, while extensive Notch pathway targeting appears to be Ciona specific. Altogether, our results provide a comprehensive insight into the specific mechanisms by which miR-124 promotes neuronal development.

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

    PubMed

    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.

  3. Ammonium channel expression is essential for brain development and function in the larva of Ciona intestinalis.

    PubMed

    Marino, Rita; Melillo, Daniela; Di Filippo, Miriam; Yamada, Atsuko; Pinto, Maria Rosaria; De Santis, Rosaria; Brown, Euan R; Matassi, Giorgio

    2007-07-01

    Ammonium uptake into the cell is known to be mediated by ammonium transport (Amt) proteins, which are present in all domains of life. The physiological role of Amt proteins remains elusive; indeed, loss-of-function experiments suggested that Amt proteins do not play an essential role in bacteria, yeast, and plants. Here we show that the reverse holds true in the tunicate Ciona intestinalis. The genome of C. intestinalis contains two AMT genes, Ci-AMT1a and Ci-AMT1b, which we show derive from an ascidian-specific gene duplication. We analyzed Ci-AMT expression during embryo development. Notably, Ci-AMT1a is expressed in the larval brain in a small number of cells defining a previously unseen V-shaped territory; these cells connect the brain cavity to the external environment. We show that the knockdown of Ci-AMT1a impairs the formation of the brain cavity and consequently the function of the otolith, the gravity-sensing organ contained in it. We speculate that the normal mechanical functioning (flotation and free movement) of the otolith may require a close regulation of ammonium salt(s) concentration in the brain cavity, because ammonium is known to affect both fluid density and viscosity; the cells forming the V territory may act as a conduit in achieving such a regulation.

  4. Developmental toxicity of benzotriazole in the protochordate Ciona intestinalis (Chordata, Ascidiae).

    PubMed

    Kadar, Eniko; Dashfield, Sarah; Hutchinson, Thomas H

    2010-01-01

    Benzotriazoles (BT) are applied as anticorrosive and de-icing agents and have been detected in a variety of aquatic ecosystems and municipal wastewater effluents. We have assessed the developmental effects of benzotriazole (CAS number 95-14-7) to the marine invertebrate Ciona intestinalis (Chordata, Ascidiae). At 15 +/- 1 degrees C, the 24 h No-Observed Effect Concentration (NOEC) and Lowest Observed Effect Concentration (LOEC) values based on embryo morphological development were 100 and >100 mg L(-1), respectively (nominal concentration under static conditions). After 48 h, the NOEC and LOEC values were 10 and 32 mg L(-1), respectively. Light and electron microscopy studies on benzotriazole-exposed larva indicated that the primary target cells were the extra-embryonic test cells, which are known to play a significant apoptotic role during ascidian metamorphosis. The visible decline of test cells in benzotriazole-exposed larvae raises the possibility that the compound interferes with the regulation of embryo development in protochordates such as C. intestinalis. Further research is warranted to assess the potential longer term sublethal impacts of benzotriazole in aquatic organisms.

  5. Cortical anchorages and cell type segregations of maternal postplasmic/PEM RNAs in ascidians.

    PubMed

    Paix, Alexandre; Yamada, Lixy; Dru, Philippe; Lecordier, Helene; Pruliere, Gerard; Chenevert, Janet; Satoh, Nori; Sardet, Christian

    2009-12-01

    Ascidian postplasmic/PEM RNAs constitute a large class of cortical maternal RNAs which include developmental determinants (macho-1 and pem-1). We have analyzed the localization, cortical anchorage and cell type segregation of postplasmic/PEM RNAs in Ciona intestinalis and Phallusia mammillata using very high-resolution fluorescent in situ hybridization. We also compared RNAs extracted from whole oocytes and from isolated cortices using microarrays and localized RNAs possessing clusters of xCACx motifs in their 3'UTRs. Based on these combined approaches we conclude that: (1) the vast majority of the 39 postplasmic/PEM RNAs (including vasa) are localized in the egg cortex. (2) Many postplasmic/PEM RNAs 3'UTR are enriched in xCACx motifs, allowing us to identify 2 novel postplasmic/PEM RNAs (PSD and MnK). (3) Postplasmic/PEM RNAs anchored to cortical Endoplasmic Reticulum (cER) and those associated with granules have different cell destinations. We propose that there are 2 distinct categories of postplasmic/PEM RNAs on the basis of their cortical anchorages and cell destinations: (1) macho-1-like postplasmic/PEM RNAs anchored to cER which segregate into somatic B8.11 cells. (2) vasa-like postplasmic/PEM RNAs associated with granules which in addition to B8.11 cells segregate into B8.12 germ cells.

  6. Reprotoxicity of the Antifoulant Chlorothalonil in Ascidians: An Ecological Risk Assessment

    PubMed Central

    Gallo, Alessandra; Tosti, Elisabetta

    2015-01-01

    Chlorothalonil is a widely used biocide in antifouling paint formulation that replaces tin-based compounds after their definitive ban. Although chlorothalonil inputs into the marine environment have significantly increased in recent years, little is known about its effect on marine animals and in particular on their reproductive processes. In this line, the aim of the present study was to investigate the effects of chlorothalonil exposure on the gamete physiology, fertilization rate and transmissible damage to offspring in the marine invertebrate Ciona intestinalis (ascidians). To identify a possible mechanism of action of chlorothalonil, electrophysiological techniques were used to study the impact on oocyte membrane excitability and on the electrical events occurring at fertilization. The pre-exposure of spermatozoa and oocytes to chlorothalonil did not affect the fertilization rate but caused damage to the offspring by inducing larval malformation. The highest toxicity was observed when fertilization was performed in chlorothalonil solutions with the lowest EC50 value. In particular, it was observed that low chlorothalonil concentrations interfered with embryo development and led to abnormal larvae, whereas high concentrations arrested embryo formation. In mature oocytes, a decrease in the amplitudes of the sodium and fertilization currents was observed, suggesting an involvement of plasma membrane ion currents in the teratogenic mechanism of chlorothalonil action. The risk estimation confirmed that the predicted no-effect concentration (PNEC) exceeded the predicted effect concentration (PEC), thus indicating that chlorothalonil may pose a risk to aquatic species. PMID:25875759

  7. High-throughput sequence analysis of Ciona intestinalis SL trans-spliced mRNAs: alternative expression modes and gene function correlates.

    PubMed

    Matsumoto, Jun; Dewar, Ken; Wasserscheid, Jessica; Wiley, Graham B; Macmil, Simone L; Roe, Bruce A; Zeller, Robert W; Satou, Yutaka; Hastings, Kenneth E M

    2010-05-01

    Pre-mRNA 5' spliced-leader (SL) trans-splicing occurs in some metazoan groups but not in others. Genome-wide characterization of the trans-spliced mRNA subpopulation has not yet been reported for any metazoan. We carried out a high-throughput analysis of the SL trans-spliced mRNA population of the ascidian tunicate Ciona intestinalis by 454 Life Sciences (Roche) pyrosequencing of SL-PCR-amplified random-primed reverse transcripts of tailbud embryo RNA. We obtained approximately 250,000 high-quality reads corresponding to 8790 genes, approximately 58% of the Ciona total gene number. The great depth of this data revealed new aspects of trans-splicing, including the existence of a significant class of "infrequently trans-spliced" genes, accounting for approximately 28% of represented genes, that generate largely non-trans-spliced mRNAs, but also produce trans-spliced mRNAs, in part through alternative promoter use. Thus, the conventional qualitative dichotomy of trans-spliced versus non-trans-spliced genes should be supplanted by a more accurate quantitative view recognizing frequently and infrequently trans-spliced gene categories. Our data include reads representing approximately 80% of Ciona frequently trans-spliced genes. Our analysis also revealed significant use of closely spaced alternative trans-splice acceptor sites which further underscores the mechanistic similarity of cis- and trans-splicing and indicates that the prevalence of +/-3-nt alternative splicing events at tandem acceptor sites, NAGNAG, is driven by spliceosomal mechanisms, and not nonsense-mediated decay, or selection at the protein level. The breadth of gene representation data enabled us to find new correlations between trans-splicing status and gene function, namely the overrepresentation in the frequently trans-spliced gene class of genes associated with plasma/endomembrane system, Ca(2+) homeostasis, and actin cytoskeleton.

  8. The Ciona intestinalis immune-related galectin genes (CiLgals-a and CiLgals-b) are expressed by the gastric epithelium.

    PubMed

    Parrinello, Daniela; Sanfratello, Maria Antonietta; Vizzini, Aiti; Testasecca, Lelia; Parrinello, Nicolò; Cammarata, Matteo

    2017-03-01

    The transcription of two Ciona intestinalis galectin genes (CiLgals-a and CiLgals-b) is uparegulated by LPS in the pharynxis (hemocytes, vessel epithelium, endostilar zones) which is retained the main organ of the immunity. In this ascidian, for the first time we show, by immunohistochemistry and in situ hybridization methods, that these two immune-related genes are expressed in the gastric epithelium of naïve ascidians, whereas the galectins appear to be only contained in the intestine columnar epithelium. In addition, according to previous results on the pharynx, the genes are also expressed and galectins produced by hemocytes scattered in the connective tissue surrounding the gut. The genes expression and galectin localization in several tissues, including the previous findings on the transcription upregulation, the constitutive expression of these genes by endostylar zones and by the gastric epithelium suggest a potential multifunctional role of these galectins. In this respect, it is of interest to define where the CiLgals are normally found as related to the tissue functions. Such an approach should be a starting point for further investigations.

  9. Transmission and Scanning Electron Microscopy of the Accessory Cells and Chorion During Development of Ciona intestinalis Type B Embryos and the Impact of Their Removal on Cell Morphology.

    PubMed

    Thompson, Helen; Shimeld, Sebastian M

    2015-06-01

    Spawned ascidian oocytes are surrounded by a membrane called the chorion (or vitelline coat) and associated with two populations of maternally-supplied cells. Outside the chorion are follicle cells, which may affect the buoyancy of eggs. Inside the chorion are test cells, which during oogenesis provision the egg and which after fertilisation contribute to the larval tunic. The structure of maternal cells may vary between species. The model ascidian Ciona intestinalis has been recently split into two species, currently named type A and type B. The ultrastructure of extraembryonic cells and structures from type A embryos has been reported. Here we describe the ultrastructure of follicle and test cells from C. intestinalis type B embryos. Test cells are about 5 µm in diameter and line the inside of the chorion of developing embryos in a dense sheet. Follicle cells are large (> 100 µm long) and spike-shaped, with many large vesicles. Terminal electron dense granules are found towards the tips of spikes, adjacent to cytoplasm containing numerous small electron dense bodies connected by filaments. These are probably vesicles containing material for the terminal granules. Removal of maternal structures and cells just after fertilisation, as commonly used in many experiments manipulating C. intestinalis development, has been reported to affect embryonic patterning. We examined the impact of this on embryonic ectoderm cells by scanning electron microscopy. Cells of embryos that developed without maternal structures still developed cilia, but had indistinct cell boundaries and a more flattened appearance than those that developed within the chorion.

  10. Species specificity of symbiosis and secondary metabolism in ascidians.

    PubMed

    Tianero, Ma Diarey B; Kwan, Jason C; Wyche, Thomas P; Presson, Angela P; Koch, Michael; Barrows, Louis R; Bugni, Tim S; Schmidt, Eric W

    2015-03-01

    Ascidians contain abundant, diverse secondary metabolites, which are thought to serve a defensive role and which have been applied to drug discovery. It is known that bacteria in symbiosis with ascidians produce several of these metabolites, but very little is known about factors governing these 'chemical symbioses'. To examine this phenomenon across a wide geographical and species scale, we performed bacterial and chemical analyses of 32 different ascidians, mostly from the didemnid family from Florida, Southern California and a broad expanse of the tropical Pacific Ocean. Bacterial diversity analysis showed that ascidian microbiomes are highly diverse, and this diversity does not correlate with geographical location or latitude. Within a subset of species, ascidian microbiomes are also stable over time (R=-0.037, P-value=0.499). Ascidian microbiomes and metabolomes contain species-specific and location-specific components. Location-specific bacteria are found in low abundance in the ascidians and mostly represent strains that are widespread. Location-specific metabolites consist largely of lipids, which may reflect differences in water temperature. By contrast, species-specific bacteria are mostly abundant sequenced components of the microbiomes and include secondary metabolite producers as major components. Species-specific chemicals are dominated by secondary metabolites. Together with previous analyses that focused on single ascidian species or symbiont type, these results reveal fundamental properties of secondary metabolic symbiosis. Different ascidian species have established associations with many different bacterial symbionts, including those known to produce toxic chemicals. This implies a strong selection for this property and the independent origin of secondary metabolite-based associations in different ascidian species. The analysis here streamlines the connection of secondary metabolite to producing bacterium, enabling further biological and

  11. Species specificity of symbiosis and secondary metabolism in ascidians

    PubMed Central

    Tianero, Ma Diarey B; Kwan, Jason C; Wyche, Thomas P; Presson, Angela P; Koch, Michael; Barrows, Louis R; Bugni, Tim S; Schmidt, Eric W

    2015-01-01

    Ascidians contain abundant, diverse secondary metabolites, which are thought to serve a defensive role and which have been applied to drug discovery. It is known that bacteria in symbiosis with ascidians produce several of these metabolites, but very little is known about factors governing these ‘chemical symbioses'. To examine this phenomenon across a wide geographical and species scale, we performed bacterial and chemical analyses of 32 different ascidians, mostly from the didemnid family from Florida, Southern California and a broad expanse of the tropical Pacific Ocean. Bacterial diversity analysis showed that ascidian microbiomes are highly diverse, and this diversity does not correlate with geographical location or latitude. Within a subset of species, ascidian microbiomes are also stable over time (R=−0.037, P-value=0.499). Ascidian microbiomes and metabolomes contain species-specific and location-specific components. Location-specific bacteria are found in low abundance in the ascidians and mostly represent strains that are widespread. Location-specific metabolites consist largely of lipids, which may reflect differences in water temperature. By contrast, species-specific bacteria are mostly abundant sequenced components of the microbiomes and include secondary metabolite producers as major components. Species-specific chemicals are dominated by secondary metabolites. Together with previous analyses that focused on single ascidian species or symbiont type, these results reveal fundamental properties of secondary metabolic symbiosis. Different ascidian species have established associations with many different bacterial symbionts, including those known to produce toxic chemicals. This implies a strong selection for this property and the independent origin of secondary metabolite-based associations in different ascidian species. The analysis here streamlines the connection of secondary metabolite to producing bacterium, enabling further biological and

  12. On the evolutionary significance and metal-binding characteristics of a monolobal transferrin from Ciona intestinalis

    PubMed Central

    Tinoco, Arthur D.; Peterson, Cynthia W.; Lucchese, Baldo; Doyle, Robert P.; Valentine, Ann M.

    2008-01-01

    Transferrins are a family of proteins that bind and transport Fe(III). Modern transferrins are typically bilobal and are believed to have evolved from an ancient gene duplication of a monolobal form. A novel monolobal transferrin, nicatransferrin (nicaTf), was identified in the primitive ascidian species Ciona intestinalis that possesses the characteristic features of the proposed ancestral Tf protein. In this work, nicaTf was expressed in Pichia pastoris. Extensive solution studies were performed on nicaTf, including UV-vis, fluorescence, CD, EPR and NMR spectroscopies, and electrospray time-of-flight mass spectrometry. The expressed protein is nonglycosylated, unlike the protein isolated from the organism. This property does not affect its ability to bind Fe(III). However, Fe(III)-bound nicaTf displays important spectral differences from other Fe(III)-bound transferrins, which are likely the consequence of differences in metal coordination. Coordination differences could also account for the weaker affinity of nicaTf for Fe(III) (log K = 18.5) compared with bilobal human serum transferrin (HsTf) (log K = 22.5 and 21.4). The Fe–nicaTf complex is not labile, as indicated by slow metal removal kinetics by the high-affinity chelator tiron at pH 7.4. The protein alternatively binds up to one equivalent of Ti(IV) or V(V), which suggests that it may transport nonferric metals. These solution studies provide insight into the structure and function of the primitive monolobal transferrin of C. intestinalis for comparison with higher order bilobal transferrins. They suggest that a major advantage for the evolution of modern transferrins, dominantly of bilobal form, is stronger Fe(III) affinity because of cooperativity. PMID:18287008

  13. Computational identification of Ciona intestinalis microRNAs.

    PubMed

    Keshavan, Raja; Virata, Michael; Keshavan, Anisha; Zeller, Robert W

    2010-02-01

    MicroRNAs (miRNAs) are conserved non-coding small RNAs with potent post-transcriptional gene regulatory functions. Recent computational approaches and sequencing of small RNAs had indicated the existence of about 80 Ciona intestinalis miRNAs, although it was not clear whether other miRNA genes were present in the genome. We undertook an alternative computational approach to look for Ciona miRNAs. Conserved non-coding sequences from the C. intestinalis genome were extracted and computationally folded to identify putative hairpin-like structures. After applying additional criteria, we obtained 458 miRNA candidates whose sequences were used to design a custom microarray. Over 100 of our predicted hairpins were identified in this array when probed with RNA from various Ciona stages. We also compared our predictions to recently deposited sequences of Ciona small RNAs and report that 170 of our predicted hairpins are represented in this data set. Altogether, about 250 of our 458 predicted miRNAs were represented in either our array data or the small-RNA sequence database. These results suggest that Ciona has a large number of genomically encoded miRNAs that play an important role in modulating gene activity in developing embryos and adults.

  14. The expression of an immune-related phenoloxidase gene is modulated in Ciona intestinalis ovary, test cells, embryos and larva.

    PubMed

    Parrinello, Daniela; Sanfratello, Maria A; Vizzini, Aiti; Cammarata, Matteo

    2015-03-01

    Two distinct Ciona intestinalis phenoloxidases (CinPO1, 2) had previously been cloned and sequenced. The CinPO2 is involved in innate immunity and is expressed by inflammatory hemocytes that populate the tunic and pharynx vessels as a response to LPS inoculation. In situ hybridization and immunohistochemistry assays on histological section, showed that the expression of this gene and the produced protein are shared with oogenesis, embryogenesis and larval morphogenesis. Intriguingly, upregulation of gene transcription was found in the test cell layer that envelopes the ovary follicle, ovulated egg, and gastrula, as well as it was modulated in the zygotic nucleus of outer balstomers of 32-cell embryo, neurula presumptive epidermis tissue and larval mesenchyme. The anti-CinPO2 antibodies, specific for adult inflammatory cells, recognize epitopes in the cytoplasm of ovarian oocytes, ovulated eggs, development stages and larval mesenchyme. The overall findings disclose the precocious activation of the CinPO2 immunity-related gene, and show a developmentally programmed expression of this phenoloxidase. Furthermore, these findings support the multifunctional roles of immunity-related genes and allows us to explore new perspectives on ascidian development and immunity.

  15. Analysis of the Transcription Regulatory Mechanism of Otx During the Development of the Sensory Vesicle in Ciona intestinalis.

    PubMed

    Oonuma, Kouhei; Hirose, Dan; Takatori, Naohito; Saiga, Hidetoshi

    2014-09-01

    Establishment of the anterior-posterior axis is an important event in the development of bilateral animals. A homeodomain transcription factor, Otx, is important for the formation of the anterior part of the embryo, and its mRNA is expressed in a continuous manner in a wide range of animals. This pattern of expression is thought to be important for the formation of anterior neural structures, but the mechanism that regulates Otx expression remains largely unknown. Towards understanding how the transcription of Otx is maintained in the cells of anterior neural structure, the sensory vesicle, during embryogenesis, we examined transcription regulatory mechanisms of Otx, using embryos of the ascidian, Ciona intestinalis, from the gastrula to tailbud stages, which have not been studied previously. We identified two genomic regions capable of mimicking the Otx expression pattern from the gastrula to tailbud stages. Putative transcription factor binding sites required for this activity were identified. Notably, distinct sets of transcription factor binding sites were required at different developmental stages for the expression of Otx, suggesting that the continuity of Otx is supported by distinct transcriptional mechanisms in the gastrula and neurula stages. Along with previous studies using Halocynthia roretzi, the present results provide insight into the evolution of transcriptional regulatory mechanism of Otx.

  16. Ciona intestinalis peroxinectin is a novel component of the peroxidase-cyclooxygenase gene superfamily upregulated by LPS.

    PubMed

    Vizzini, Aiti; Parrinello, Daniela; Sanfratello, Maria Antonietta; Mangano, Valentina; Parrinello, Nicolò; Cammarata, Matteo

    2013-09-01

    Peroxinectins function as hemoperoxidase and cell adhesion factor involved in invertebrate immune reaction. In this study, the ascidian (Ciona intestinalis) peroxinectin gene (CiPxt) and its expression during the inflammatory response have been examined. CiPxt is a new member of the peroxidase-cyclooxygenase gene superfamily that contains both the peroxidase domain and the integrin KGD (Lys-Gly-Asp) binding motif. A phylogenetic tree showed that CiPxt is very close to the chordate group and appears to be the outgroup of mammalian MPO, EPO and TPO clades. The CiPxt molecular structure model resulted superimposable to the human myeloperoxidase. The CiPxt mRNA expression is upregulated by LPS inoculation suggesting it is involved in C. intestinalis inflammatory response. The CiPxt was expressed in hemocytes (compartment/morula cells), vessel epithelium, and unilocular refractile granulocytes populating the inflamed tunic matrix and in the zones 7, 8 and 9 of the endostyle, a special pharynx organs homolog to the vertebrate thyroid gland.

  17. Transforming growth factor β (CiTGF-β) gene expression is induced in the inflammatory reaction of Ciona intestinalis.

    PubMed

    Vizzini, Aiti; Di Falco, Felicia; Parrinello, Daniela; Sanfratello, Maria Antonietta; Cammarata, Matteo

    2016-02-01

    Transforming growth factor (TGF-β) is a well-known component of a regulatory cytokines superfamily that has pleiotropic functions in a broad range of cell types and is involved, in vertebrates, in numerous physiological and pathological processes. In the current study, we report on Ciona intestinalis molecular characterisation and expression of a transforming growth factor β homologue (CiTGF-β). The gene organisation, phylogenetic tree and modelling supported the close relationship with the mammalian TGF suggesting that the C. intestinalis TGF-β gene shares a common ancestor in the chordate lineages. Functionally, real-time PCR analysis showed that CiTGF-β was transcriptionally upregulated in the inflammatory process induced by LPS inoculation, suggesting that is involved in the first phase and significant in the secondary phase of the inflammatory response in which cell differentiation occurs. In situ hybridisation assays revealed that the genes transcription was upregulated in the pharynx, the main organ of the ascidian immune system, and expressed by cluster of hemocytes inside the pharynx vessels. These data supported the view that CiTGF-β is a potential molecule in immune defence systems against bacterial infection.

  18. Ephrin-mediated restriction of ERK1/2 activity delimits the number of pigment cells in the Ciona CNS

    PubMed Central

    Haupaix, Nicolas; Abitua, Philip B.; Sirour, Cathy; Yasuo, Hitoyoshi; Levine, Michael; Hudson, Clare

    2014-01-01

    Recent evidence suggests that ascidian pigment cells are related to neural crest-derived melanocytes of vertebrates. Using live-imaging, we determine a revised cell lineage of the pigment cells in Ciona intestinalis embryos. The neural precursors undergo successive rounds of anterior-posterior (A-P) oriented cell divisions, starting at the blastula 64-cell stage. A previously unrecognized fourth A-P oriented cell division in the pigment cell lineage leads to the generation of the post-mitotic pigment cell precursors. We provide evidence that MEK/ERK signals are required for pigment cell specification until approximately 30 minutes after the final cell division has taken place. Following each of the four A-P oriented cell divisions, ERK1/2 is differentially activated in the posterior sister cells, into which the pigment cell lineage segregates. Eph/ephrin signals are critical during the third A-P oriented cell division to spatially restrict ERK1/2 activation to the posterior daughter cell. Targeted inhibition of Eph/ephrin signals results in, at neurula stages, anterior expansion of both ERK1/2 activation and a pigment cell lineage marker and subsequently, at larval stages, supernumerary pigment cells. We discuss the implications of these findings with respect to the evolution of the vertebrate neural crest. PMID:25062608

  19. Ephrin-mediated restriction of ERK1/2 activity delimits the number of pigment cells in the Ciona CNS.

    PubMed

    Haupaix, Nicolas; Abitua, Philip B; Sirour, Cathy; Yasuo, Hitoyoshi; Levine, Michael; Hudson, Clare

    2014-10-01

    Recent evidence suggests that ascidian pigment cells are related to neural crest-derived melanocytes of vertebrates. Using live-imaging, we determine a revised cell lineage of the pigment cells in Ciona intestinalis embryos. The neural precursors undergo successive rounds of anterior-posterior (A-P) oriented cell divisions, starting at the blastula 64-cell stage. A previously unrecognized fourth A-P oriented cell division in the pigment cell lineage leads to the generation of the post-mitotic pigment cell precursors. We provide evidence that MEK/ERK signals are required for pigment cell specification until approximately 30min after the final cell division has taken place. Following each of the four A-P oriented cell divisions, ERK1/2 is differentially activated in the posterior sister cells, into which the pigment cell lineage segregates. Eph/ephrin signals are critical during the third A-P oriented cell division to spatially restrict ERK1/2 activation to the posterior daughter cell. Targeted inhibition of Eph/ephrin signals results in, at neurula stages, anterior expansion of both ERK1/2 activation and a pigment cell lineage marker and subsequently, at larval stages, supernumerary pigment cells. We discuss the implications of these findings with respect to the evolution of the vertebrate neural crest.

  20. The CNS connectome of a tadpole larva of Ciona intestinalis (L.) highlights sidedness in the brain of a chordate sibling

    PubMed Central

    Ryan, Kerrianne; Lu, Zhiyuan; Meinertzhagen, Ian A

    2016-01-01

    Left-right asymmetries in brains are usually minor or cryptic. We report brain asymmetries in the tiny, dorsal tubular nervous system of the ascidian tadpole larva, Ciona intestinalis. Chordate in body plan and development, the larva provides an outstanding example of brain asymmetry. Although early neural development is well studied, detailed cellular organization of the swimming larva’s CNS remains unreported. Using serial-section EM we document the synaptic connectome of the larva’s 177 CNS neurons. These formed 6618 synapses including 1772 neuromuscular junctions, augmented by 1206 gap junctions. Neurons are unipolar with at most a single dendrite, and few synapses. Some synapses are unpolarised, others form reciprocal or serial motifs; 922 were polyadic. Axo-axonal synapses predominate. Most neurons have ciliary organelles, and many features lack structural specialization. Despite equal cell numbers on both sides, neuron identities and pathways differ left/right. Brain vesicle asymmetries include a right ocellus and left coronet cells. DOI: http://dx.doi.org/10.7554/eLife.16962.001 PMID:27921996

  1. Postplasmic/PEM RNAs: a class of localized maternal mRNAs with multiple roles in cell polarity and development in ascidian embryos.

    PubMed

    Prodon, François; Yamada, Lixy; Shirae-Kurabayashi, Maki; Nakamura, Yoriko; Sasakura, Yasunori

    2007-07-01

    Ascidian is a good model to understand the cellular and molecular mechanisms responsible for mRNA localization with the discovery of a large family of localized maternal mRNAs, called postplasmic/PEM RNAs, which includes more than 40 members in three different ascidian species (Halocynthia roretzi, Ciona intestinalis, and C. savignyi). Among these mRNAs, two types (Type I and Type II) have been identified and show two different localization patterns from fertilization to the eight-cell stage. At the eight-cell stage, both types concentrate to a macromolecular cortical structure called CAB (for Centrosome Attracting Body) in the posterior-vegetal B4.1 blastomeres. The CAB is responsible for unequal cleavages and the partitioning of postplasmic/PEM RNAs at the posterior pole of embryos during cleavage stages. It has also been suggested that the CAB region could contain putative germ granules. In this review, we discuss recent data obtained on the distribution of Type I postplasmic/PEM RNAs from oogenesis to late development, in relation to their localization and translational control. We have first regrouped localization patterns for Type I and Type II into a comparative diagram and included all important definitions in the field. We also have made an exhaustive classification of their embryonic expression profiles (Type I or Type II), and analyzed their functions after knockdown and/or overexpression experiments and the role of the 3'-untranslated region (3'UTR) controlling both their localization and translation. Finally, we propose a speculative model integrating recent data, and we also discuss the relationship between postplasmic/PEM RNAs, posterior specification, and germ cell formation in ascidians.

  2. Origin and Dispersal History of Two Colonial Ascidian Clades in the Botryllus schlosseri Species Complex

    PubMed Central

    Nydam, Marie L.

    2017-01-01

    Human-induced global warming and species introductions are rapidly altering the composition and functioning of Earth’s marine ecosystems. Ascidians (Phylum Chordata, Subphylum Tunicata, Class Ascidiacea) are likely to play an increasingly greater role in marine communities. The colonial ascidian B. schlosseri is a cryptic species complex comprising five genetically divergent clades (A-E). Clade A is a global species, and Clade E has so far been identified in European waters only. Using the largest mitochondrial cytochrome oxidase I datasets yet assembled, we determine the origin and dispersal history of these species. Nucleotide diversity and Approximate Bayesian Computation analyses support a Pacific origin for Clade A, with two likely dispersal scenarios that both show the northwestern Atlantic populations establishing early in the history of the species. Both Discrete Phylogeographic Analysis and Approximate Bayesian Computation support an origin of Clade E on the French side of the English Channel. An unsampled lineage evolved from the French lineage, which reflects the conclusion from the median joining network that not all Clade E lineages have been sampled. This unsampled lineage gave rise to the haplotypes on the English side of the English Channel, which were the ancestors to the Mediterranean and Bay of Biscay populations. Clade E has a wider geographic range than previously thought, and shows evidence of recent range expansion. Both Clade A and Clade E should be considered widespread species: Clade A globally and Clade E within Europe. PMID:28107476

  3. Invasion genetics of the Ciona intestinalis species complex: from regional endemism to global homogeneity.

    PubMed

    Zhan, Aibin; Macisaac, Hugh J; Cristescu, Melania E

    2010-11-01

    Determining the degree of population connectivity and investigating factors driving genetic exchange at various geographical scales are essential to understanding population dynamics and spread potential of invasive species. Here, we explore these issues in the highly invasive vase tunicate, Ciona intestinalis, a species whose invasion history has been obscured by its poorly understood taxonomy and population genetics. Recent phylogenetic and comparative genomic studies suggest that C. intestinalis is a cryptic species complex consisting of at least three species. We reconstructed phylogenies based on both mitochondrial (cytochrome c oxidase subunit 3--NADH dehydrogenase subunit 1 region and NADH dehydrogenase subunit 4 gene) and nuclear (internal transcribed spacer 1) sequences, results of which support four major phylogroups corresponding to the previously reported spA, spB and Ciona spp. (spC) as well as an undescribed cryptic species (spD). While spC and spD remain restricted to their native ranges in the Mediterranean Sea and Black Sea, respectively, the highly invasive species (spA and spB) have disjunct global distributions. Despite extensive interspecific divergences, we identified low phylogeographical structure within these two invasive species. Haplotype network analyses revealed comparatively limited mutation steps among haplotypes within each species. Population genetic analyses based on two mtDNA fragments and eight unlinked microsatellites illustrated relatively low population differentiation and high population connectivity at both regional and continental scales in the two invasive species. Human-mediated dispersal coupled with a high potential for natural dispersal is probably responsible for the observed genetic homogeneity.

  4. Embryo Microinjection and Electroporation in the Chordate Ciona intestinalis.

    PubMed

    Kari, Willi; Zeng, Fan; Zitzelsberger, Lena; Will, Johannes; Rothbächer, Ute

    2016-10-16

    Simple model organisms are instrumental for in vivo studies of developmental and cellular differentiation processes. Currently, the evolutionary distance to man of conventional invertebrate model systems and the complexity of genomes in vertebrates are critical challenges to modeling human normal and pathological conditions. The chordate Ciona intestinalis is an invertebrate chordate that emerged from a common ancestor with the vertebrates and may represent features at the interface between invertebrates and vertebrates. A common body plan with much simpler cellular and genomic composition should unveil gene regulatory network (GRN) links and functional genomics readouts explaining phenomena in the vertebrate condition. The compact genome of Ciona, a fixed embryonic lineage with few divisions and large cells, combined with versatile community tools foster efficient gene functional analyses in this organism. Here, we present several crucial methods for this promising model organism, which belongs to the closest sister group to vertebrates. We present protocols for transient transgenesis by electroporation, along with microinjection-mediated gene knockdown, which together provide the means to study gene function and genomic regulatory elements. We extend our protocols to provide information on how community databases are utilized for in silico design of gene regulatory or gene functional experiments. An example study demonstrates how novel information can be gained on the interplay, and its quantification, of selected neural factors conserved between Ciona and man. Furthermore, we show examples of differential subcellular localization in embryonic cells, following DNA electroporation in Ciona zygotes. Finally, we discuss the potential of these protocols to be adapted for tissue specific gene interference with emerging gene editing methods. The in vivo approaches in Ciona overcome major shortcomings of classical model organisms in the quest of unraveling conserved

  5. Embryo Microinjection and Electroporation in the Chordate Ciona intestinalis

    PubMed Central

    Kari, Willi; Zeng, Fan; Zitzelsberger, Lena; Will, Johannes; Rothbächer, Ute

    2016-01-01

    Simple model organisms are instrumental for in vivo studies of developmental and cellular differentiation processes. Currently, the evolutionary distance to man of conventional invertebrate model systems and the complexity of genomes in vertebrates are critical challenges to modeling human normal and pathological conditions. The chordate Ciona intestinalis is an invertebrate chordate that emerged from a common ancestor with the vertebrates and may represent features at the interface between invertebrates and vertebrates. A common body plan with much simpler cellular and genomic composition should unveil gene regulatory network (GRN) links and functional genomics readouts explaining phenomena in the vertebrate condition. The compact genome of Ciona, a fixed embryonic lineage with few divisions and large cells, combined with versatile community tools foster efficient gene functional analyses in this organism. Here, we present several crucial methods for this promising model organism, which belongs to the closest sister group to vertebrates. We present protocols for transient transgenesis by electroporation, along with microinjection-mediated gene knockdown, which together provide the means to study gene function and genomic regulatory elements. We extend our protocols to provide information on how community databases are utilized for in silico design of gene regulatory or gene functional experiments. An example study demonstrates how novel information can be gained on the interplay, and its quantification, of selected neural factors conserved between Ciona and man. Furthermore, we show examples of differential subcellular localization in embryonic cells, following DNA electroporation in Ciona zygotes. Finally, we discuss the potential of these protocols to be adapted for tissue specific gene interference with emerging gene editing methods. The in vivo approaches in Ciona overcome major shortcomings of classical model organisms in the quest of unraveling conserved

  6. Diversity of Actinobacteria Associated with the Marine Ascidian Eudistoma toealensis.

    PubMed

    Steinert, Georg; Taylor, Michael W; Schupp, Peter J

    2015-08-01

    Ascidians have yielded a wide variety of bioactive natural products. The colonial ascidian Eudistoma toealensis from Micronesia has been identified as the source of a series of staurosporine derivatives, though the exact origin of these derivatives is still unknown. To identify known staurosporine-producing microbes associated with E. toealensis, we analyzed with 16S rRNA gene tag pyrosequencing the overall bacterial community and focused on potential symbiotic bacteria already known from other ascidians or other marine hosts, such as sponges. The described microbiota was one of very high diversity, comprising 43 phyla: two from archaea, 34 described bacterial phyla, and seven candidate bacterial phyla. Many bacteria, which are renowned community members of other ascidians and marine holobionts, such as sponges and corals, were also part of the E. toealensis microbial community. Furthermore, two known producers of indolocarbazoles, Salinispora and Verrucosispora, were found with high abundance exclusively in the ascidian tissue, suggesting that microbial symbionts and not the organism itself may be the true producers of the staurosporines in E. toealensis.

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

    PubMed

    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.

  8. Evidence of a Native Northwest Atlantic COI Haplotype Clade in the Cryptogenic Colonial Ascidian Botryllus schlosseri.

    PubMed

    Yund, Philip O; Collins, Catherine; Johnson, Sheri L

    2015-06-01

    The colonial ascidian Botryllus schlosseri should be considered cryptogenic (i.e., not definitively classified as either native or introduced) in the Northwest Atlantic. Although all the evidence is quite circumstantial, over the last 15 years most research groups have accepted the scenario of human-mediated dispersal and classified B. schlosseri as introduced; others have continued to consider it native or cryptogenic. We address the invasion status of this species by adding 174 sequences to the growing worldwide database for the mitochondrial gene cytochrome c oxidase subunit I (COI) and analyzing 1077 sequences to compare genetic diversity of one clade of haplotypes in the Northwest Atlantic with two hypothesized source regions (the Northeast Atlantic and Mediterranean). Our results lead us to reject the prevailing view of the directionality of transport across the Atlantic. We argue that the genetic diversity patterns at COI are far more consistent with the existence of at least one haplotype clade in the Northwest Atlantic (and possibly a second) that substantially pre-dates human colonization from Europe, with this native North American clade subsequently introduced to three sites in Northeast Atlantic and Mediterranean waters. However, we agree with past researchers that some sites in the Northwest Atlantic have more recently been invaded by alien haplotypes, so that some populations are currently composed of a mixture of native and invader haplotypes.

  9. Evolution of Ciona intestinalis Tumor necrosis factor alpha (CiTNFα): Polymorphism, tissues expression, and 3D modeling.

    PubMed

    Vizzini, Aiti; Giovanna, Parisi Maria; Cardinale, Laura; Testasecca, Lelia; Cammarata, Matteo

    2017-02-01

    Although the Tumor necrosis factor gene superfamily seems to be very conserved in vertebrates, phylogeny, tissue expression, genomic and gene organization, protein domains and polymorphism analyses showed that a strong change has happened mostly in invertebrates in which protochordates were a constraint during the immune-molecules history and evolution. RT PCR was used to investigate differential gene expression in different tissues. The expression shown was greater in the pharynx. Single-nucleotide polymorphism has been investigated in Ciona intestinalis Tumor necrosis factor alpha (CiTNFα) mRNA isolated from the pharynx of 30 ascidians collected from Licata, Sicily (Italy), by denaturing gradient gel electrophoresis (DGGE). For this analysis, CiTNFα nucleotide sequence was separated into two fragments, TNF-1 and -2, respectively, of 630 and 540 bp. We defined 23 individual DGGE patterns (named 1 to 10 for TNF-1 and 1 to 13 for TNF-2). Five patterns for TNF-1 accounted for <10% of the individuals, whereas the pattern 13 of TNF-2 accounted for >20% of the individuals. All the patterns were verified by direct sequencing. Single base-pair mutations were observed mainly within COOH-terminus, leading to 30 nucleotide sequence variants and 30 different coding sequences segregating in two main different clusters. Although most of the base mutations were silent, four propeptide variants were detected and six amino acid replacements occurred within COOH-terminus. Statistical tests for neutrality indicated negative selection pressure on signal and mature peptide domains, but possible positive selection pressure on COOH-terminus domain. Lastly we displayed the in silico 3D structure analysis including the CiTNFα variable region.

  10. Morphological Differences between Larvae of the Ciona intestinalis Species Complex: Hints for a Valid Taxonomic Definition of Distinct Species.

    PubMed

    Pennati, Roberta; Ficetola, Gentile Francesco; Brunetti, Riccardo; Caicci, Federico; Gasparini, Fabio; Griggio, Francesca; Sato, Atsuko; Stach, Thomas; Kaul-Strehlow, Sabrina; Gissi, Carmela; Manni, Lucia

    2015-01-01

    The cosmopolitan ascidian Ciona intestinalis is the most common model species of Tunicata, the sister-group of Vertebrata, and widely used in developmental biology, genomics and evolutionary studies. Recently, molecular studies suggested the presence of cryptic species hidden within the C. intestinalis species, namely C. intestinalis type A and type B. So far, no substantial morphological differences have been identified between individuals belonging to the two types. Here we present morphometric, immunohistochemical, and histological analyses, as well as 3-D reconstructions, of late larvae obtained by cross-fertilization experiments of molecularly determined type A and type B adults, sampled in different seasons and in four different localities. Our data point to quantitative and qualitative differences in the trunk shape of larvae belonging to the two types. In particular, type B larvae exhibit a longer pre-oral lobe, longer and relatively narrower total body length, and a shorter ocellus-tail distance than type A larvae. All these differences were found to be statistically significant in a Discriminant Analysis. Depending on the number of analyzed parameters, the obtained discriminant function was able to correctly classify > 93% of the larvae, with the remaining misclassified larvae attributable to the existence of intra-type seasonal variability. No larval differences were observed at the level of histology and immunohistochemical localization of peripheral sensory neurons. We conclude that type A and type B are two distinct species that can be distinguished on the basis of larval morphology and molecular data. Since the identified larval differences appear to be valid diagnostic characters, we suggest to raise both types to the rank of species and to assign them distinct names.

  11. Morphological Differences between Larvae of the Ciona intestinalis Species Complex: Hints for a Valid Taxonomic Definition of Distinct Species

    PubMed Central

    Pennati, Roberta; Ficetola, Gentile Francesco; Brunetti, Riccardo; Caicci, Federico; Gasparini, Fabio; Griggio, Francesca; Sato, Atsuko; Stach, Thomas; Kaul-Strehlow, Sabrina; Gissi, Carmela; Manni, Lucia

    2015-01-01

    The cosmopolitan ascidian Ciona intestinalis is the most common model species of Tunicata, the sister-group of Vertebrata, and widely used in developmental biology, genomics and evolutionary studies. Recently, molecular studies suggested the presence of cryptic species hidden within the C. intestinalis species, namely C. intestinalis type A and type B. So far, no substantial morphological differences have been identified between individuals belonging to the two types. Here we present morphometric, immunohistochemical, and histological analyses, as well as 3-D reconstructions, of late larvae obtained by cross-fertilization experiments of molecularly determined type A and type B adults, sampled in different seasons and in four different localities. Our data point to quantitative and qualitative differences in the trunk shape of larvae belonging to the two types. In particular, type B larvae exhibit a longer pre-oral lobe, longer and relatively narrower total body length, and a shorter ocellus-tail distance than type A larvae. All these differences were found to be statistically significant in a Discriminant Analysis. Depending on the number of analyzed parameters, the obtained discriminant function was able to correctly classify > 93% of the larvae, with the remaining misclassified larvae attributable to the existence of intra-type seasonal variability. No larval differences were observed at the level of histology and immunohistochemical localization of peripheral sensory neurons. We conclude that type A and type B are two distinct species that can be distinguished on the basis of larval morphology and molecular data. Since the identified larval differences appear to be valid diagnostic characters, we suggest to raise both types to the rank of species and to assign them distinct names. PMID:25955391

  12. LPS injection reprograms the expression and the 3' UTR of a CAP gene by alternative polyadenylation and the formation of a GAIT element in Ciona intestinalis.

    PubMed

    Vizzini, Aiti; Bonura, Angela; Longo, Valeria; Sanfratello, Maria Antonietta; Parrinello, Daniela; Cammarata, Matteo; Colombo, Paolo

    2016-09-01

    The diversification of cellular functions is one of the major characteristics of multicellular organisms which allow cells to modulate their gene expression, leading to the formation of transcripts and proteins with different functions and concentrations in response to different stimuli. CAP genes represent a widespread family of proteins belonging to the cysteine-rich secretory protein, antigen 5 and pathogenesis-related 1 superfamily which, it has been proposed, play key roles in the infection process and the modulation of immune responses in host animals. The ascidian Ciona intestinalis represents a group of proto-chordates with an exclusively innate immune system that has been widely studied in the field of comparative and developmental immunology. Using this biological system, we describe the identification of a novel APA mechanism by which an intronic polyadenylation signal is activated by LPS injection, leading to the formation of a shorter CAP mRNA capable of expressing the first CAP exon plus 19 amino acid residues whose sequence is contained within the first intron of the annotated gene. Furthermore, such an APA event causes the expression of a translational controlling cis-acting GAIT element which is not present in the previously isolated CAP isoform and identified in the 3'-UTR of other immune-related genes, suggesting an intriguing scenario in which both transcriptional and post-transcriptional control mechanisms are involved in the activation of the CAP gene during inflammatory response in C. intestinalis.

  13. Toxicity of Hg, Cu, Cd, and Cr on early developmental stages of Ciona intestinalis (Chordata, Ascidiacea) with potential application in marine water quality assessment.

    PubMed

    Bellas, J; Vázquez, E; Beiras, R

    2001-08-01

    The toxicity of mercury, copper, cadmium and chromium on sperm viability, fertilisation, embryogenesis and larval attachment of Ciona intestinalis was examined. Fertilisation rate (FR) showed a small decrease even at the highest metal concentration tested. The median effective concentrations (EC50) reducing rates of embryogenesis and larval attachment by 50% were 54 microg Hg/l (0.27 microM), 46 microg Cu/l (0.72 microM), 838 microg Cd/l (7.46 microM), 10,318 microg Cr/l (198 microM), and 35 microg Hg/l (0.18 microM), 34 microg Cu/l (0.54 microM) and 11,755 microg Cr/l (226 microM), respectively. Therefore, Hg is three times more toxic than Cu (on a molar basis), ca. 30 times more toxic than Cd and ca. 1000 times more toxic than Cr to early stages of C. intestinalis. Rates of larval attachment and embryogenesis were the most sensitive endpoints, although the latter is more advisable for routine assessment of seawater quality because of its greater simplicity. In addition to bivalves and sea-urchins, ascidian embryos can provide biological criteria for seawater quality standards taking into account the sensitivity of a chordate and contributing to the detection of harmful chemicals with no marked effect on the species currently in use in seawater quality bioassays.

  14. Localization of antimicrobial peptides in the tunic of Ciona intestinalis (Ascidiacea, Tunicata) and their involvement in local inflammatory-like reactions

    PubMed Central

    Di Bella, M.A.; Fedders, H.; De Leo, G.; Leippe, M.

    2011-01-01

    Tunicates comprising a wide variety of different species synthesize antimicrobial peptides as important effector molecules of the innate immune system. Recently, two putative gene families coding for antimicrobial peptides were identified in the expressed sequence tag database of the tunicate Ciona intestinalis. Two synthetic peptides representing the cationic core region of one member of each of the families displayed potent antibacterial and antifungal activities. Moreover, the natural peptides were demonstrated to be synthesized and stored in distinct hemocyte types. Here, we investigated the presence of these natural peptides, namely Ci-MAM-A and Ci-PAP-A, in the tunic of C. intestinalis considering that the ascidian tunic is a body surface barrier exposed to constant microbial assault. Furthermore, as the tunic may represent a major route of entry for pathogen invasion after its damage we monitored the location of these peptides upon a local inflammatory-like reaction induced by injection of foreign cells. Using immunocytochemistry and electron microscopy both peptides were localized to the tunic and were massively present in granulocytes of inflamed tissue. Conclusively, antimicrobial peptides may constitute a chemical barrier within the tunic of urochordates. PMID:24371555

  15. The Comparative Organismal Approach in Evolutionary Developmental Biology: Insights from Ascidians and Cavefish.

    PubMed

    Jeffery, William R

    2016-01-01

    Important contributions to evolutionary developmental biology have been made using the comparative organismal approach. As examples, I describe insights obtained from studies of Molgula ascidians and Astyanax cavefish.

  16. A cDNA resource from the basal chordate Ciona intestinalis.

    PubMed

    Satou, Yutaka; Yamada, Lixy; Mochizuki, Yasuaki; Takatori, Naohito; Kawashima, Takeshi; Sasaki, Akane; Hamaguchi, Makoto; Awazu, Satoko; Yagi, Kasumi; Sasakura, Yasunori; Nakayama, Akie; Ishikawa, Hisayoshi; Inaba, Kazuo; Satoh, Nori

    2002-08-01

    The genome of the basal choradate Ciona intestinalis contains a basic set of genes with less redundancy compared to the vertebrate genome. Extensive EST analyses, cDNA sequencing, and clustering yielded "Ciona intestinalis Gene Collection Release 1," which contains cDNA clones for 13,464 genes, covering nearly 85% of the Ciona mRNA species. This release is ready for use in cDNA cloning, micro/macroarray analysis, and other comprehensive genome-wide analyses for further molecular studies of basal chordates.

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

    PubMed

    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.

  18. The evolution of larval morphology and swimming performance in ascidians.

    PubMed

    McHenry, Matthew J; Patek, Sheila N

    2004-06-01

    The complexity of organismal function challenges our ability to understand the evolution of animal locomotion. To meet this challenge, we used a combination of biomechanics, phylogenetic comparative analyses, and theoretical morphology to examine evolutionary changes in body shape and how those changes affected swimming performance in ascidian larvae. Results of phylogenetic comparative analyses suggest that coloniality evolved at least three times among ascidians and that colonial species have a convergent larval morphology characterized by a large trunk volume and shorter tail length in proportion to the trunk. To explore the functional significance of this evolutionary change, we first verified the accuracy of a mathematical model of swimming biomechanics in a solitary (C. intestinalis) and a colonial (D. occidentalis) species and then ran numerous simulations of the model that varied in tail length and trunk volume. The results of these simulations were used to construct landscapes of speed and cost of transport predictions within a trunk volume/tail length morphospace. Our results suggest that the reduction of proportionate tail length in colonial species resulted in improved energetic economy of swimming. The increase in the size of larvae with the origin of coloniality facilitated faster swimming with negligible energetic cost, but may have required a reduction in adult fecundity. Therefore, the evolution of ascidians appears to be influenced by a trade-off between the fecundity of the adult stage and the swimming performance of larvae.

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

    PubMed

    Dishaw, Larry J; Flores-Torres, Jaime; Lax, Simon; Gemayel, Kristina; Leigh, Brittany; Melillo, Daniela; Mueller, M Gail; Natale, Lenina; Zucchetti, Ivana; De Santis, Rosaria; Pinto, Maria Rosaria; Litman, Gary W; Gilbert, Jack A

    2014-01-01

    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. *Arsenic (+3 oxidation state) methyltransferase and the methylation of arsenicals in the invertebrate chordate ciona intestinalis

    EPA Science Inventory

    Biotransformation of inorganic arsenic (iAs) involves methylation catalyzed by arsenic (+3 oxidation state) methyltransferase (As3mt) , yielding mono-, di-, and trimethylated arsenicals. A comparative genomic approach focused on Ciona intestinaJis, an invertebrate chordate, was u...

  1. New distributional data on ascidian fauna (Tunicata: Ascidiacea) from Mandapam coast, Gulf of Mannar, India

    PubMed Central

    Akram, Soban A; Arshan, Kaleem ML

    2016-01-01

    Abstract Background Ascidians play a key role in the ecology and biodiversity of marine ecosystem. Ascidians can be transported in ship ballast water and while attached to ship and boat hulls. Heavy traffic by domestic and international ships as well as cargo vessels between the major and minor ports warrants continuous monitoring for new introductions of ascidians. The Mandapam coast is situated in the Gulf of Mannar, India, a marine hot spot area in the Indian Ocean which provides an environment suitable for the settlement of ascidians. New information A total of 30 species of ascidians were reported from Mandapam coastal waters, of which 26 species were new to the study area and five species: Ecteinascidia turbinata, Eudistoma carnosum, Trididemnum caelatum, T. vermiforme and Didemnum spadix, were new to India. PMID:27099557

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

    PubMed

    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.

  3. Prochloron-ascidian symbioses: Photosynthetic potential and productivity

    NASA Technical Reports Server (NTRS)

    Lewin, R. A.; Cheng, L.; Alberte, R. S.

    1983-01-01

    The chlorophyll content of didemnid asidians with symbiotic algae (Prochloron) from oligotropic tropical marine waters around Palau, Western Carolin Islands is discussed. Several species contain as much chlorophyll per unit dry weight as many herbaceous crop plants and more than do other symbiotic associations such as lichens, green Hydra, etc. Their chlorphyllA/B ratios (3-9) were generally much lighter than those of angiosperms (2-4). Where they abound, Prochloron - ascidian symbiosis could make a major contribution to the productivity, especially in localized areas of tropical marine waters characterized by low nutrient levels and high irradiance.

  4. Photosymbiotic ascidians from Pari Island (Thousand Islands, Indonesia).

    PubMed

    Hirose, Euichi; Iskandar, Budhi Hascaryo; Wardiatno, Yusli

    2014-01-01

    Photosymbiotic ascidian fauna were surveyed in the subtidal zone off Pari Island in the Thousand Islands (Java Sea, Indonesia). Nine species were recorded: Didemnum molle, Trididemnum miniatum, Lissoclinum patella, L. punctatum, L. timorense, Diplosoma gumavirens, D. simile, D. simileguwa, and D. virens. All of these species have been previously recorded in the Ryukyu Archipelago, Japan. Diplosoma gumavirens and D. simileguwa were originally described from the Ryukyu Archipelago in 2009 and 2005, respectively, and all of the observed species are potentially widely distributed in Indo-West Pacific coral reefs.

  5. Photosymbiotic ascidians from Pari Island (Thousand Islands, Indonesia)

    PubMed Central

    Hirose, Euichi; Iskandar, Budhi Hascaryo; Wardiatno, Yusli

    2014-01-01

    Abstract Photosymbiotic ascidian fauna were surveyed in the subtidal zone off Pari Island in the Thousand Islands (Java Sea, Indonesia). Nine species were recorded: Didemnum molle, Trididemnum miniatum, Lissoclinum patella, L. punctatum, L. timorense, Diplosoma gumavirens, D. simile, D. simileguwa, and D. virens. All of these species have been previously recorded in the Ryukyu Archipelago, Japan. Diplosoma gumavirens and D. simileguwa were originally described from the Ryukyu Archipelago in 2009 and 2005, respectively, and all of the observed species are potentially widely distributed in Indo–West Pacific coral reefs. PMID:25061385

  6. Ascidian tunicate extracts attenuate rheumatoid arthritis in a collagen-induced murine model.

    PubMed

    Hong, Seong-Ho; Kwone, Jung-Taek; Lee, Jae-Ho; Lee, Somin; Lee, Ah Young; Cho, Won-Young; Bat-Erdene, Munkhjargal; Choi, Byeong-Dae; Cho, Myung-Haing

    2014-06-01

    Murine rheumatoid arthritis models are often used to investigate the potential therapeutic effects of candidate drugs. The present study has been conducted in order to investigate the therapeutic efficacy of ascidian tunicate extracts in a collagen-induced arthritis DBA1/J mice model. Four types of formulas, ascidian tunicate extracts (ATE), crude ascidian tunicate glycans (ATEC), ascidian tunicate extracts with licorice extracts (ATEL), and crude ascidian tunicate glycans with licorice extracts (ATECL) were orally administered into DBA/1J mice for 3 weeks and paw edema and thickness were evaluated. Changes in inflammatory proteins and cytokines levels were monitored in hind leg tissues by Western blot and quantitative PCR analysis. The oral administration of ascidian tunicate extracts alleviated paw edema and improved the histological hind leg cartilage status. The extracts also reduced the matrix metalloproteinase-9 (MMP-9) protein and prostaglandin E synthase (PGES) levels. In addition, the extracts-treated groups showed increased interleukin-10 (IL-10) levels compared with the non-treated group. These findings suggest that orally administered ascidian tunicate extracts might have potential therapeutic effects for the treatment of rheumatoid arthritis.

  7. Ascidians as excellent models for studying cellular events in the chordate body plan.

    PubMed

    Ogura, Yosuke; Sasakura, Yasunori

    2013-08-01

    The larvae of non-vertebrate chordate ascidians consist of countable numbers of cells. With this feature, ascidians provide us with excellent models for studying cellular events in the construction of the chordate body. This review discusses the recent observations of morphogenetic movements and cell cycles and divisions along with tissue specifications during ascidian embryogenesis. Unequal cleavages take place at the posterior blastomeres during the early cleavage stages of ascidians, and the structure named the centrosome-attracting body restricts the position of the nuclei near the posterior pole to achieve the unequal cleavages. The most-posterior cells differentiate into the primordial germ cells. The gastrulation of ascidians starts as early as the 110-cell stage. During gastrulation, the endodermal cells show two-step changes in cell shape that are crucial for gastrulation. The ascidian notochord is composed of only 40 cells. The 40 cells align to form a single row by an event named the convergent extension, and then the notochord cells undergo vacuolation to transform the notochord into a single hollowed tube. The strictly restricted number of notochord cells is achieved by the regulated number of cell divisions coupled with the differentiation of the cells conducted by a key transcription factor, Brachyury. The dorsally located neural tube is a characteristic of chordates. During the closure of the ascidian neural tube, the epidermis surrounding the neural plate moves toward the midline to close the neural fold. This morphogenetic movement is allowed by an elongation of interphase in the epidermal cell cycles.

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

    PubMed

    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.

  9. Bioadhesion in ascidians: a developmental and functional genomics perspective

    PubMed Central

    Pennati, Roberta; Rothbächer, Ute

    2015-01-01

    The development of bioadhesives inspired from marine animals is a promising approach to generate new tissue-compatible medical components. A number of marine species, through their adhesive properties, also represent significant foulers that become increasingly problematic to aquaculture, shipping or local biodiversity. In order to develop more sophisticated man-made glues and/or efficient fouling resistant surfaces, it is important to understand the mechanical, structural and molecular properties of adhesive organs in selected species. Ascidians are marine invertebrates with larvae that opportunistically attach to almost any type of submerged surface to undergo metamorphosis into permanently sessile adults. Not only do they represent a globally important fouling organism, but they are becoming increasingly popular as model organisms for developmental biology. The latter is due to their phylogenetic position as the sister group to the vertebrates and their cellular and molecular accessibility for experimentation. In this paper, we review the mechanisms of larval adhesion in ascidians and draw conclusions from comparative analyses of selected species. We further discuss how knowledge from a developmental and functional genomics point of view can advance our understanding of cellular and molecular signatures and their hierarchical usage in animal adhesive organs. PMID:25657840

  10. Repression of Rx gene on the left side of the sensory vesicle by Nodal signaling is crucial for right-sided formation of the ocellus photoreceptor in the development of Ciona intestinalis.

    PubMed

    Yoshida, Keita; Saiga, Hidetoshi

    2011-06-01

    Nodal signaling plays an essential role in the establishment of left-right asymmetry in various animals. However, it is largely unknown how Nodal signaling is involved in the establishment of the left-right asymmetric morphology. In this study, the role of Nodal signaling in the left-right asymmetric ocellus formation in the ascidian, Ciona intestinalis was dealt with. During the development of C. intestinalis, the ocellus pigment cell forms on the midline and moves to the right side of the midline. Then, the photoreceptor cells form on the right side of the sensory vesicle (SV). Ci-Nodal is expressed on the left side of the SV in the developing tail bud embryo. When Nodal signaling is inhibited, the ocellus pigment cell form but remain on the midline, and expression of marker genes of the ocellus photoreceptor cells is ectopically detected on the left side as well as on the right side of the SV in the larva. Furthermore, Ci-Rx, which is essential for the ocellus differentiation, turns out to be negatively regulated by the Nodal signaling on the left side of the SV, even though it is required for the right-sided photoreceptor formation. These results indicate that Nodal signaling controls the left-right asymmetric ocellus formation in the development of C. intestinalis.

  11. The Whereabouts of an Ancient Wanderer: Global Phylogeography of the Solitary Ascidian Styela plicata

    PubMed Central

    Pineda, Mari Carmen; López-Legentil, Susanna; Turon, Xavier

    2011-01-01

    Genetic tools have greatly aided in tracing the sources and colonization history of introduced species. However, recurrent introductions and repeated shuffling of populations may have blurred some of the genetic signals left by ancient introductions. Styela plicata is a solitary ascidian distributed worldwide. Although its origin remains unclear, this species is believed to have spread worldwide by travelling on ship's hulls. The goals of this study were to infer the genetic structure and global phylogeography of S. plicata and to look for present-day and historical genetic patterns. Two genetic markers were used: a fragment of the mitochondrial gene Cytochrome Oxidase subunit I (COI) and a fragment of the nuclear gene Adenine Nucleotide Transporter/ADP-ATP Translocase (ANT). A total of 368 individuals for COI and 315 for ANT were sequenced from 17 locations worldwide. The levels of gene diversity were moderate for COI to high for ANT. The Mediterranean populations showed the least diversity and allelic richness for both markers, while the Indian, Atlantic and Pacific Oceans had the highest gene and nucleotide diversities. Network and phylogenetic analyses with COI and ANT revealed two groups of alleles separated by 15 and 4 mutational steps, respectively. The existence of different lineages suggested an ancient population split. However, the geographic distributions of these groups did not show any consistent pattern, indicating different phylogeographic histories for each gene. Genetic divergence was significant for many population-pairs irrespective of the geographic distance among them. Stochastic introduction events are reflected in the uneven distribution of COI and ANT allele frequencies and groups among many populations. Our results confirmed that S. plicata has been present in all studied oceans for a long time, and that recurrent colonization events and occasional shuffling among populations have determined the actual genetic structure of this species

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

    PubMed Central

    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

  13. Sensing charges of the Ciona intestinalis voltage-sensing phosphatase.

    PubMed

    Villalba-Galea, Carlos A; Frezza, Ludivine; Sandtner, Walter; Bezanilla, Francisco

    2013-11-01

    Voltage control over enzymatic activity in voltage-sensitive phosphatases (VSPs) is conferred by a voltage-sensing domain (VSD) located in the N terminus. These VSDs are constituted by four putative transmembrane segments (S1 to S4) resembling those found in voltage-gated ion channels. The putative fourth segment (S4) of the VSD contains positive residues that likely function as voltage-sensing elements. To study in detail how these residues sense the plasma membrane potential, we have focused on five arginines in the S4 segment of the Ciona intestinalis VSP (Ci-VSP). After implementing a histidine scan, here we show that four arginine-to-histidine mutants, namely R223H to R232H, mediate voltage-dependent proton translocation across the membrane, indicating that these residues transit through the hydrophobic core of Ci-VSP as a function of the membrane potential. These observations indicate that the charges carried by these residues are sensing charges. Furthermore, our results also show that the electrical field in VSPs is focused in a narrow hydrophobic region that separates the extracellular and intracellular space and constitutes the energy barrier for charge crossing.

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

    PubMed

    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.

  15. Ascidian depth zonation on sublittoral hard substrates off deer island, New Brunswick, Canada

    NASA Astrophysics Data System (ADS)

    Hatfield, C.; Logan, A.; Thomas, M. L. H.

    1992-02-01

    The upper surfaces of sublittoral hard substrates in the Deer Island region of the Bay of Fundy, New Brunswick, support diverse, depth-zoned epibenthic communities of which ascidians form a minor part. Their population density was quantitatively studied from photo-transects taken between mean low water (MLW) and 30 m depth at four sites off the Deer Island coast and from 30-140 m depth along two photo-transects in Head Harbour Passage. All photo-analyses were aided by collections from transect survey sites, wharf pilings and salmon cage floats, to yield a total of 15 ascidian species encountered. Ascidians were found at all depths at the four shallow sites. Halocynthia pyriformis and Boltenia ovifera are most common at depths of less than 20 m, while Aplidium pallidum, Didemnum albidum and other species exhibit a marked increase in abundance below this depth. Cluster analysis of ascidians shows an association between B. echinata and B. ovifera, which may reflect resource partitioning, and between A. pallidum-D. albidum and Molgula sp.— A. stellatum, the ecological significance of which are as yet unknown. The community in Head Harbour Passage is animal-dominated and in its deeper sections often shows three-dimensional bottom relief from horse mussel shells. D. albidum, the commonest ascidian, shows a close association with Modiolus modiolus, to which it is normally attached, suggesting that mussel beds may minimize the possibility of dislodgement and even confer a feeding advantage on this ascidian.

  16. Genetic Distances in Three Ascidian Species determined by PCR Technique

    PubMed Central

    Yoon, Jong-Man

    2016-01-01

    ABSTRACT Seven oligonucleotides primers were shown to generate the shared loci, specific loci, unique shared loci to each species and shared loci by the three species which could be obviously scored. In the present study, 7 oligonucleotides primers produced 401 total loci in the Styela clava (SC) species, 390 in the Halocynthia roretzi (HR) and 434 in the Styela plicata (SP), respectively. Seven oligonucleotides primers generated 275 specific loci in the SC, 341 in the HR and 364 in the SP species, respectively. The oligonucleotides primer BION-23 generated 28 unique loci to each species in the SP species. Especially, the oligonucleotides primer BION-25 produced 7 unique loci to each species, which were identifying each species in the SP species. BION-17 distinguished 21 shared loci by the three ascidian species, major and/or minor fragments of sizes, which were identical in almost all of the samples. Based on the average bandsharing values of all samples, the similarity matrix ranged from 0.519 to 0.774 in the SC species, from 0.261 to 0.683 in the HR species and from 0.346 to 0.730 in the SP species. As regards average bandsharing value (BS) results, individuals from SC species (0.661±0.081) exhibited higher bandsharing values than did individuals from HR species (0.555±0.074) (P<0.05). The dendrogram obtained by the seven oligonucleotides primers indicates three genetic groups. In three ascidian species, the shortest genetic distance (0.071) exhibiting significant molecular difference was also between individual no. 20 and no. 21 within the SP species. PMID:28144642

  17. Retroduplication and loss of parental genes is a mechanism for the generation of intronless genes in Ciona intestinalis and Ciona savignyi.

    PubMed

    Kim, Dong Seon; Wang, Yao; Oh, Hye Ji; Choi, Dongjin; Lee, Kangseok; Hahn, Yoonsoo

    2014-12-01

    Tunicates, the sister clade of vertebrates, have miniature genomes and numerous intronless genes compared to other animals. It is still unclear how the tunicates acquired such a large number of intronless genes. Here, we analyzed sequences and intron-exon organizations of homologous genes from two closely related tunicates, Ciona intestinalis and Ciona savignyi. We found seven cases in which ancestral introns of a gene were completely lost in a species after their divergence. In four cases, both the intronless copy and the intron-containing copy were present in the genome, indicating that the intronless copy was generated by retroduplication. In the other three cases, the intron-containing copy was absent, implying it was lost after retroduplication. This result suggests that retroduplication and loss of parental genes is a major mechanism for the accumulation of intronless genes in tunicates.

  18. Proteome map of the neural complex of the tunicate Ciona intestinalis, the closest living relative to vertebrates.

    PubMed

    Saxena, Sandeep; Dupont, Sam; Meghah, Vuppalapaty; Lakshmi, Mula G Meena; Singh, Sachin K; Swamy, Cherukuvada V Brahmendra; Idris, Mohammed M

    2013-03-01

    Ciona intestinalis (the common sea squirt) is the closest living chordate relative to vertebrates with cosmopolitan presence worldwide. It has a relatively simple nervous system and development, making it a widely studied alternative model system in neuroscience and developmental biology. The use of Ciona as a model organism has increased significantly after the draft genome was published. In this study, we describe the first proteome map of the neural complex of C. intestinalis. A total of 544 proteins were identified based on 1DE and 2DE FTMS/ITMSMS analyses. Proteins were annotated against the Ciona database and analyzed to predict their molecular functions, roles in biological processes, and position in constructed network pathways. The identified Ciona neural complex proteome was found to map onto vertebrate nervous system pathways, including cytoskeleton remodeling neurofilaments, cell adhesion through the histamine receptor signaling pathway, γ-aminobutyric acid-A receptor life cycle neurophysiological process, glycolysis, and amino acid metabolism. The proteome map of the Ciona neural complex is the first step toward a better understanding of several important processes, including the evolution and regeneration capacity of the Ciona nervous system.

  19. Down under the tunic: bacterial biodiversity hotspots and widespread ammonia-oxidizing archaea in coral reef ascidians

    PubMed Central

    Erwin, Patrick M; Pineda, Mari Carmen; Webster, Nicole; Turon, Xavier; López-Legentil, Susanna

    2014-01-01

    Ascidians are ecologically important components of marine ecosystems yet the ascidian microbiota remains largely unexplored beyond a few model species. We used 16S rRNA gene tag pyrosequencing to provide a comprehensive characterization of microbial symbionts in the tunic of 42 Great Barrier Reef ascidian samples representing 25 species. Results revealed high bacterial biodiversity (3 217 unique operational taxonomic units (OTU0.03) from 19 described and 14 candidate phyla) and the widespread occurrence of ammonia-oxidizing Thaumarchaeota in coral reef ascidians (24 of 25 host species). The ascidian microbiota was clearly differentiated from seawater microbial communities and included symbiont lineages shared with other invertebrate hosts as well as unique, ascidian-specific phylotypes. Several rare seawater microbes were markedly enriched (200–700 fold) in the ascidian tunic, suggesting that the rare biosphere of seawater may act as a conduit for horizontal symbiont transfer. However, most OTUs (71%) were rare and specific to single hosts and a significant correlation between host relatedness and symbiont community similarity was detected, indicating a high degree of host-specificity and potential role of vertical transmission in structuring these communities. We hypothesize that the complex ascidian microbiota revealed herein is maintained by the dynamic microenvironments within the ascidian tunic, offering optimal conditions for different metabolic pathways such as ample chemical substrate (ammonia-rich host waste) and physical habitat (high oxygen, low irradiance) for nitrification. Thus, ascidian hosts provide unique and fertile niches for diverse microorganisms and may represent an important and previously unrecognized habitat for nitrite/nitrate regeneration in coral reef ecosystems. PMID:24152714

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

    PubMed

    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.

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

    PubMed

    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.

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

    PubMed

    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. Delayed insemination results in embryo mortality in a brooding ascidian.

    PubMed

    Stewart-Savage, J; Phillippi, A; Yund, P O

    2001-08-01

    We explored the effects of temporal variation in sperm availability on fertilization and subsequent larval development in the colonial ascidian Botryllus schlosseri, a brooding hermaphrodite that has a sexual cycle linked to an asexual zooid replacement cycle. We developed a method to quantify the timing of events early in this cycle, and then isolated colonies before the start of the cycle and inseminated them at various times. Colony-wide fertilization levels (assayed by early cleavage) increased from zero to 100% during the period when the siphons of a new generation of zooids were first opening, and remained high for 24 h before slowly declining over the next 48 h. Because embryos are brooded until just before the zooids degenerate at the end of a cycle, delayed fertilization might also affect whether embryos can complete development within the cycle. Consequently, we also determined the effect of delayed insemination on successful embryo development through larval release and metamorphosis. When fertilization was delayed beyond the completion of siphon opening, there was an exponential decline in the percentage of eggs that ultimately produced a metamorphosed larva at the end of the cycle. Thus, even though the majority of oocytes can be fertilized when insemination is delayed for up to 48 h, the resulting embryos cannot complete development before the brooding zooids degenerate.

  4. Evidence for dynamic and multiple roles for huntingtin in Ciona intestinalis.

    PubMed

    Idris, Mohammed M; Thorndyke, Michael C; Brown, Euan R

    2013-12-01

    Although mutations in the huntingtin gene (HTT) due to poly-Q expansion cause neuropathology in humans (Huntington’s disease; HD), the normal function(s) of the gene and its protein (HTT) remain obscure. With new information from recently sequenced invertebrate genomes, the study of new animal models opens the possibility of a better understanding of HTT function and its evolution. To these ends, we studied huntingtin expression pattern and dynamics in the invertebrate chordate Ciona intestinalis. Ciona huntingtin (Ci-HTT) shows a biphasic expression pattern during larval development and prior to metamorphosis. A single form of huntingtin protein is present until the early larval stages, at which time two different mass proteins become evident in the metamorphically competent larva. An antibody against Ci-HTT labeled 50 cells in the trunk mesenchyme regions in pre-hatching and hatched larvae and probably represents the distribution of the light form of the protein. Dual labeling with anti-Ci-HTT and anti-aldoketoreductase confirmed the presence of Ci-HTT in mesenchyme cells. Suppression of Ci-HTT RNA by a morpholino oligonucleotide reduced the number and apparent mobility of Ci-HTT positive cells. In Ciona, HTT expression has a dynamic temporal and spatial expression pattern that in ontogeny precedes metamorphosis. Although our results may reflect a derived function for the protein in pre- and post-metamorphic events in Ciona, we also note that as in vertebrates, there is evidence for multiple differential temporal expression, indicating that this protein probably has multiple roles in ontogeny and cell migration.

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

    PubMed

    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.

  6. Initial deployment of the cardiogenic gene regulatory network in the basal chordate, Ciona intestinalis.

    PubMed

    Woznica, Arielle; Haeussler, Maximilian; Starobinska, Ella; Jemmett, Jessica; Li, Younan; Mount, David; Davidson, Brad

    2012-08-01

    The complex, partially redundant gene regulatory architecture underlying vertebrate heart formation has been difficult to characterize. Here, we dissect the primary cardiac gene regulatory network in the invertebrate chordate, Ciona intestinalis. The Ciona heart progenitor lineage is first specified by Fibroblast Growth Factor/Map Kinase (FGF/MapK) activation of the transcription factor Ets1/2 (Ets). Through microarray analysis of sorted heart progenitor cells, we identified the complete set of primary genes upregulated by FGF/Ets shortly after heart progenitor emergence. Combinatorial sequence analysis of these co-regulated genes generated a hypothetical regulatory code consisting of Ets binding sites associated with a specific co-motif, ATTA. Through extensive reporter analysis, we confirmed the functional importance of the ATTA co-motif in primary heart progenitor gene regulation. We then used the Ets/ATTA combination motif to successfully predict a number of additional heart progenitor gene regulatory elements, including an intronic element driving expression of the core conserved cardiac transcription factor, GATAa. This work significantly advances our understanding of the Ciona heart gene network. Furthermore, this work has begun to elucidate the precise regulatory architecture underlying the conserved, primary role of FGF/Ets in chordate heart lineage specification.

  7. Generation of Germ-Free Ciona intestinalis for Studies of Gut-Microbe Interactions.

    PubMed

    Leigh, Brittany A; Liberti, Assunta; Dishaw, Larry J

    2016-01-01

    Microbes associate with animal hosts, often providing shelter in a nutrient-rich environment. The gut, however, can be a harsh environment with members of the microbiome settling in distinct niches resulting in more stable, adherent biofilms. These diverse communities can provide orders of magnitude more gene products than the host genome; selection and maintenance of a functionally relevant and useful microbiome is now recognized to be an essential component of homeostasis. Germ-free (GF) model systems allow dissection of host-microbe interactions in a simple and direct way where each member of the symbiosis can be studied in isolation. In addition, because immune defenses in the gut are often naïve in GF animals, host immune recognition and responses during the process of colonization can be studied. Ciona intestinalis, a basal chordate, is a well-characterized developmental model system and holds promise for addressing some of these important questions. With transparent juveniles, Ciona can be exposed to distinct bacterial isolates by inoculating GF artificial seawater; concentrated bacteria can subsequently be visualized in vivo if fluorescent stains are utilized. Rearing GF Ciona is a first step in untangling the complex dialogue between bacteria and innate immunity during colonization.

  8. Contrasting global genetic patterns in two biologically similar, widespread and invasive Ciona species (Tunicata, Ascidiacea)

    PubMed Central

    Bouchemousse, Sarah; Bishop, John D. D.; Viard, Frédérique

    2016-01-01

    Human-mediated dispersal interplays with natural processes and complicates understanding of the biogeographical history of species. This is exemplified by two invasive tunicates, Ciona robusta (formerly Ciona intestinalis type A) and C. intestinalis (formerly Ciona intestinalis type B), globally distributed and sympatric in Europe. By gathering new mitochondrial sequences that were merged with published datasets, we analysed genetic patterns in different regions, with a focus on 1) their sympatric range and 2) allopatric populations in N and S America and southern Europe. In the sympatric range, the two species display contrasting genetic diversity patterns, with low polymorphism in C. robusta supporting the prevalent view of its recent introduction. In the E Pacific, several genetic traits support the non-native status of C. robusta. However, in the NE Pacific, this appraisal requires a complex scenario of introduction and should be further examined supported by extensive sampling efforts in the NW Pacific (putative native range). For C. intestinalis, Bayesian analysis suggested a natural amphi-North Atlantic distribution, casting doubt on its non-native status in the NW Atlantic. This study shows that both natural and human-mediated dispersal have influenced genetic patterns at broad scales; this interaction lessens our ability to confidently ascertain native vs. non-native status of populations, particularly of those species that are globally distributed. PMID:27137892

  9. Generation of Germ-Free Ciona intestinalis for Studies of Gut-Microbe Interactions

    PubMed Central

    Leigh, Brittany A.; Liberti, Assunta; Dishaw, Larry J.

    2016-01-01

    Microbes associate with animal hosts, often providing shelter in a nutrient-rich environment. The gut, however, can be a harsh environment with members of the microbiome settling in distinct niches resulting in more stable, adherent biofilms. These diverse communities can provide orders of magnitude more gene products than the host genome; selection and maintenance of a functionally relevant and useful microbiome is now recognized to be an essential component of homeostasis. Germ-free (GF) model systems allow dissection of host-microbe interactions in a simple and direct way where each member of the symbiosis can be studied in isolation. In addition, because immune defenses in the gut are often naïve in GF animals, host immune recognition and responses during the process of colonization can be studied. Ciona intestinalis, a basal chordate, is a well-characterized developmental model system and holds promise for addressing some of these important questions. With transparent juveniles, Ciona can be exposed to distinct bacterial isolates by inoculating GF artificial seawater; concentrated bacteria can subsequently be visualized in vivo if fluorescent stains are utilized. Rearing GF Ciona is a first step in untangling the complex dialogue between bacteria and innate immunity during colonization. PMID:28082961

  10. Multiple origins of the ascidian-Prochloron symbiosis: molecular phylogeny of photosymbiotic and non-symbiotic colonial ascidians inferred from 18S rDNA sequences.

    PubMed

    Yokobori, Shin-Ichi; Kurabayashi, Atsushi; Neilan, Brett A; Maruyama, Tadashi; Hirose, Euichi

    2006-07-01

    In the tropics, certain didemnid ascidians harbor the prokaryotic photosymbiont Prochloron. To date, this photosymbiosis has been found in four didemnid genera that include non-symbiotic species. Here, we report the molecular phylogeny of symbiotic and non-symbiotic didemnids based on their 18S rDNA sequences. The data cover all four genera containing symbiotic species and one other genus comprised of only non-symbiotic species. Near-complete nucleotide sequences of 18S rDNAs were determined for four non-didemnid species and 52 didemnid samples (five genera), including 48 photosymbiotic samples collected from the Ryukyu Archipelago, the Great Barrier Reef, Hawaii, and Bali. Our phylogenetic trees indicated a monophyletic origin of the family Didemnidae, as well as each of the didemnid genera. The results strongly support the hypothesis that establishment of the ascidian-Prochloron symbiosis occurred independently in the Didemnidae lineage at least once in each of the genera that possess symbiotic species.

  11. Tunic morphology and viral surveillance in diseased Korean ascidians: Soft tunic syndrome in the edible ascidian, Halocynthia roretzi (Drasche), in aquaculture.

    PubMed

    Kitamura, S-I; Ohtake, S-I; Song, J-Y; Jung, S-J; Oh, M-J; Choi, B-D; Azumi, K; Hirose, E

    2010-02-01

    'Soft tunic syndrome' causes mass mortality in the edible ascidian Halocynthia roretzi in Korean and Japanese aquaculture. In histopathological comparison, there were no specific differences between diseased specimens from Korea and Japan, indicating that soft tunic syndrome occurring in Korea and Japan is the same disease. No bacterial or protozoan cells were microscopically detected in either healthy or diseased tunics suggesting they are not the direct causes of soft tunic syndrome. Attempts were made to isolate virus from affected ascidians taking into account temperature conditions in which soft tunic syndrome is most prevalent in the field. However, no viruses were isolated from diseased or non-diseased specimens using chinook salmon embryo (CHSE-214), flounder fin (FFN) or epithelioma papillosum cyprini (EPC) cell lines.

  12. Blood circulation in the ascidian tunicate Corella inflata (Corellidae)

    PubMed Central

    2016-01-01

    The body of the ascidian tunicate Corella inflata is relatively transparent. Thus, the circulatory system can be visualized by injecting high molecular weight fluorescein labeled dextran into the heart or the large vessels at the ends of the heart without surgery to remove the body wall. In addition, after staining with neutral red, the movement of blood cells can be easily followed to further characterize the circulatory system. The heart is two gently curved concentric tubes extending across the width of the animal. The inner myocardial tube has a partial constriction approximately in the middle. As in other tunicates, the heart is peristaltic and periodically reverses direction. During the branchial phase blood leaves the anterior end of the heart by two asymmetric vessels that connect to the two sides of the branchial basket. Blood then flows in both transverse directions through a complex system of ducts in the basket into large ventral and dorsal vessels which carry blood back to the visceral organs in the posterior of the animal. During the visceral phase blood leaves the posterior end of the heart in two vessels that repeatedly bifurcate and fan into the stomach and gonads. Blood velocity, determined by following individual cells in video frames, is high and pulsatory near the heart. A double peak in velocity at the maximum may be due to the constriction in the middle of the heart tube. Blood velocity progressively decreases with distance from the heart. In peripheral regions with vessels of small diameter blood cells frequently collide with vessel walls and cell motion is erratic. The estimated volume of blood flow during each directional phase is greater than the total volume of the animal. Circulating blood cells are confined to vessels or ducts in the visible parts of the animal and retention of high molecular weight dextran in the vessels is comparable to that seen in vertebrates. These are characteristics of a closed circulatory system. PMID:27994977

  13. Blood circulation in the ascidian tunicate Corella inflata (Corellidae).

    PubMed

    Konrad, Michael W

    2016-01-01

    The body of the ascidian tunicate Corella inflata is relatively transparent. Thus, the circulatory system can be visualized by injecting high molecular weight fluorescein labeled dextran into the heart or the large vessels at the ends of the heart without surgery to remove the body wall. In addition, after staining with neutral red, the movement of blood cells can be easily followed to further characterize the circulatory system. The heart is two gently curved concentric tubes extending across the width of the animal. The inner myocardial tube has a partial constriction approximately in the middle. As in other tunicates, the heart is peristaltic and periodically reverses direction. During the branchial phase blood leaves the anterior end of the heart by two asymmetric vessels that connect to the two sides of the branchial basket. Blood then flows in both transverse directions through a complex system of ducts in the basket into large ventral and dorsal vessels which carry blood back to the visceral organs in the posterior of the animal. During the visceral phase blood leaves the posterior end of the heart in two vessels that repeatedly bifurcate and fan into the stomach and gonads. Blood velocity, determined by following individual cells in video frames, is high and pulsatory near the heart. A double peak in velocity at the maximum may be due to the constriction in the middle of the heart tube. Blood velocity progressively decreases with distance from the heart. In peripheral regions with vessels of small diameter blood cells frequently collide with vessel walls and cell motion is erratic. The estimated volume of blood flow during each directional phase is greater than the total volume of the animal. Circulating blood cells are confined to vessels or ducts in the visible parts of the animal and retention of high molecular weight dextran in the vessels is comparable to that seen in vertebrates. These are characteristics of a closed circulatory system.

  14. Patellamide E: a new cyclic peptide from the ascidian Lissoclinum patella.

    PubMed

    McDonald, L A; Ireland, C M

    1992-03-01

    A new cyclic peptide, patellamide E [1], was isolated from the ascidian Lissoclinum patella collected at Pulau Salu, Singapore. Its structure was determined by nmr spectroscopy, and its absolute configuration by acid hydrolysis and analysis of the derivatized constituent amino acids by hplc. Patellamide E was mildly cytotoxic against human colon tumor cells in vitro.

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

    PubMed Central

    Degasperi, Valentina; Gasparini, Fabio; Shimeld, Sebastian M; Sinigaglia, Chiara; Burighel, Paolo; Manni, Lucia

    2009-01-01

    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. PMID:19737381

  16. Natural Products from Antarctic Colonial Ascidians of the Genera Aplidium and Synoicum: Variability and Defensive Role

    PubMed Central

    Núñez-Pons, Laura; Carbone, Marianna; Vázquez, Jennifer; Rodríguez, Jaime; Nieto, Rosa María; Varela, María Mercedes; Gavagnin, Margherita; Avila, Conxita

    2012-01-01

    Ascidians have developed multiple defensive strategies mostly related to physical, nutritional or chemical properties of the tunic. One of such is chemical defense based on secondary metabolites. We analyzed a series of colonial Antarctic ascidians from deep-water collections belonging to the genera Aplidium and Synoicum to evaluate the incidence of organic deterrents and their variability. The ether fractions from 15 samples including specimens of the species A. falklandicum, A. fuegiense, A. meridianum, A. millari and S. adareanum were subjected to feeding assays towards two relevant sympatric predators: the starfish Odontaster validus, and the amphipod Cheirimedon femoratus. All samples revealed repellency. Nonetheless, some colonies concentrated defensive chemicals in internal body-regions rather than in the tunic. Four ascidian-derived meroterpenoids, rossinones B and the three derivatives 2,3-epoxy-rossinone B, 3-epi-rossinone B, 5,6-epoxy-rossinone B, and the indole alkaloids meridianins A–G, along with other minoritary meridianin compounds were isolated from several samples. Some purified metabolites were tested in feeding assays exhibiting potent unpalatabilities, thus revealing their role in predation avoidance. Ascidian extracts and purified compound-fractions were further assessed in antibacterial tests against a marine Antarctic bacterium. Only the meridianins showed inhibition activity, demonstrating a multifunctional defensive role. According to their occurrence in nature and within our colonial specimens, the possible origin of both types of metabolites is discussed. PMID:23015772

  17. Ascidian (Chordata-Tunicata) glycosaminoglycans: extraction, purification, biochemical, and spectroscopic analysis.

    PubMed

    Pavão, Mauro S G

    2015-01-01

    Sulfated polysaccharides with unique structures of the chondroitin/dermatan and heparin/heparan families of sulfated glycosaminoglycans have been described in several species of ascidians (Chordata-Tunicata). These unique sulfated glycans have been isolated from-ascidians and characterized by biochemical and spectroscopic methods. The ascidian glycans can be extracted by different tissues or cells by proteolytic digestion followed by cetylpyridinium chloride/ethanol precipitation. The total glycans are then fractionated by ion-exchange chromatography on DEAE-cellulose and/or Mono Q (HR 5/5) columns. Alternatively, precipitation with different ethanol concentrations can be employed. An initial analysis of the purified ascidian glycans is carried out by agarose gel electrophoresis on diaminopropane/acetate buffer, before or after digestion with specific glycosaminoglycan lyases or deaminative cleavage with nitrous acid. The disaccharides formed by exhaustive degradation of the glycans is purified by gel-filtration chromatography on a Superdex-peptide column and analyzed by HPLC on a strong ion exchange Sax-Spherisorb column. 1H or 13C nuclear magnetic resonance spectroscopy in one or two dimensions is used to confirm the structure of the intact glycans.

  18. Mediterranean diet

    MedlinePlus

    ... provider if you should take a calcium supplement. Wine is a common part of a Mediterranean eating ... but some people should not drink alcohol. Avoid wine if you are prone to alcohol abuse, pregnant, ...

  19. Stochasticity in space, persistence in time: genetic heterogeneity in harbour populations of the introduced ascidian Styela plicata

    PubMed Central

    Pineda, Mari-Carmen; Lorente, Beatriz; López-Legentil, Susanna; Palacín, Creu

    2016-01-01

    Spatio-temporal changes in genetic structure among populations provide crucial information on the dynamics of secondary spread for introduced marine species. However, temporal components have rarely been taken into consideration when studying the population genetics of non-indigenous species. This study analysed the genetic structure of Styela plicata, a solitary ascidian introduced in harbours and marinas of tropical and temperate waters, across spatial and temporal scales. A fragment of the mitochondrial gene Cytochrome Oxidase subunit I (COI) was sequenced from 395 individuals collected at 9 harbours along the NW Mediterranean coast and adjacent Atlantic waters (> 1,200 km range) at two time points 5 years apart (2009 and 2014). The levels of gene diversity were relatively low for all 9 locations in both years. Analyses of genetic differentiation and distribution of molecular variance revealed strong genetic structure, with significant differences among many populations, but no significant differences among years. A weak and marginally significant correlation between geographic distance and gene differentiation was found. Our results revealed spatial structure and temporal genetic homogeneity in S. plicata, suggesting a limited role of recurrent, vessel-mediated transport of organisms among small to medium-size harbours. Our study area is representative of many highly urbanized coasts with dense harbours. In these environments, the episodic chance arrival of colonisers appears to determine the genetic structure of harbour populations and the genetic composition of these early colonising individuals persists in the respective harbours, at least over moderate time frames (five years) that encompass ca. 20 generations of S. plicata. PMID:27366653

  20. Amphioxus and ascidian Dmbx homeobox genes give clues to the vertebrate origins of midbrain development.

    PubMed

    Takahashi, Tokiharu; Holland, Peter W H

    2004-07-01

    The ancestral chordate neural tube had a tripartite structure, comprising anterior, midbrain-hindbrain boundary (MHB) and posterior regions. The most anterior region encompasses both forebrain and midbrain in vertebrates. It is not clear when or how the distinction between these two functionally and developmentally distinct regions arose in evolution. Recently, we reported a mouse PRD-class homeobox gene, Dmbx1, expressed in the presumptive midbrain at early developmental stages, and the hindbrain at later stages, with exclusion from the MHB. This gene provides a route to investigate the evolution of midbrain development. We report the cloning, genomic structure, phylogeny and embryonic expression of Dmbx genes from amphioxus and from Ciona, representing the two most closely related lineages to the vertebrates. Our analyses show that Dmbx genes form a distinct, ancient, homeobox gene family, with highly conserved sequence and genomic organisation, albeit more divergent in Ciona. In amphioxus, no Dmbx expression is observed in the neural tube, supporting previous arguments that the MHB equivalent region has been secondarily modified in evolution. In Ciona, the CiDmbx gene is detected in neural cells caudal to Pax2/5/8-positive cells (MHB homologue), in the Hox-positive region, but, interestingly, not in any cells rostral to them. These results suggest that a midbrain homologue is missing in Ciona, and argue that midbrain development is a novelty that evolved specifically on the vertebrate lineage. We discuss the evolution of midbrain development in relation to the ancestry of the tripartite neural ground plan and the origin of the MHB organiser.

  1. Endozoicomonas Are Specific, Facultative Symbionts of Sea Squirts

    PubMed Central

    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

  2. Dissection of a Ciona regulatory element reveals complexity of cross-species enhancer activity

    PubMed Central

    Chen, Wei-Chung; Pauls, Stefan; Bacha, Jamil; Elgar, Greg; Loose, Matthew; Shimeld, Sebastian M.

    2014-01-01

    Vertebrate genomes share numerous conserved non-coding elements, many of which function as enhancer elements and are hypothesised to be under evolutionary constraint due to a need to be bound by combinations of sequence-specific transcription factors. In contrast, few such conserved elements can be detected between vertebrates and their closest invertebrate relatives. Despite this lack of sequence identity, cross-species transgenesis has identified some cases where non-coding DNA from invertebrates drives reporter gene expression in transgenic vertebrates in patterns reminiscent of the expression of vertebrate orthologues. Such instances are presumed to reflect the presence of conserved suites of binding sites in the regulatory regions of invertebrate and vertebrate orthologues, such that both regulatory elements can correctly interpret the trans-activating environment. Shuffling of binding sites has been suggested to lie behind loss of sequence conservation; however this has not been experimentally tested. Here we examine the underlying basis of enhancer activity for the Ciona intestinalis βγ-crystallin gene, which drives expression in the lens of transgenic vertebrates despite the Ciona lineage predating the evolution of the lens. We construct an interactive gene regulatory network (GRN) for vertebrate lens development, allowing network interactions to be robustly catalogued and conserved network components and features to be identified. We show that a small number of binding motifs are necessary for Ciona βγ-crystallin expression, and narrow down the likely factors that bind to these motifs. Several of these overlap with the conserved core of the vertebrate lens GRN, implicating these sites in cross species function. However when we test these motifs in a transgenic vertebrate they prove to be dispensable for reporter expression in the lens. These results show that current models depicting cross species enhancer function as dependent on conserved binding

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

    PubMed

    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.

  4. Quinone and Hydroquinone Metabolites from the Ascidians of the Genus Aplidium

    PubMed Central

    Bertanha, Camila Spereta; Januário, Ana Helena; Alvarenga, Tavane Aparecida; Pimenta, Letícia Pereira; e Silva, Márcio Luis Andrade; Cunha, Wilson Roberto; Pauletti, Patrícia Mendonça

    2014-01-01

    Ascidians of the genus Aplidium are recognized as an important source of chemical diversity and bioactive natural products. Among the compounds produced by this genus are non-nitrogenous metabolites, mainly prenylated quinones and hydroquinones. This review discusses the isolation, structural elucidation, and biological activities of quinones, hydroquinones, rossinones, longithorones, longithorols, floresolides, scabellones, conicaquinones, aplidinones, thiaplidiaquinones, and conithiaquinones. A compilation of the 13C-NMR spectral data of these compounds is also presented. PMID:24927227

  5. The alien ascidian Styela clava now invading the Sea of Marmara (Tunicata: Ascidiacea).

    PubMed

    Çinar, Melih Ertan

    2016-01-01

    During the implementation of a large project aimed to investigate the benthic community structures of the Sea of Marmara, specimens of the invasive ascidian species Styela clava were collected on natural substrata (rocks) at 10 m depth at one locality (Karamürsel) in İzmit Bay. The specimens were mature, containing gametes, indicating that the species had become established in the area. The Sea of Marmara seems to provide suitable conditions for this species to survive and form proliferating populations.

  6. Shallow-water Ascidians from Matua Island (central Kuril Islands, NW Pacific).

    PubMed

    Sanamyan, Karen; Sanamyan, Nadya

    2017-02-16

    Fifteen species of ascidians were identified in the material collected at Matua Island. Two species are new, Botryllus flavus n. sp. and Distaplia matua n. sp. The first species occurs also at Kamchatka waters, while the second is probably an endemic of Kuril Islands. The genus Macrenteron Redikorzev, 1927 is synonymized with Aplidium Savigny, 1816 and a new name Aplidium macrenteron nom. nov. is proposed for its type species.

  7. Ammonia-oxidizing Crenarchaeota and nitrification inside the tissue of a colonial ascidian.

    PubMed

    Martínez-García, Manuel; Stief, Peter; Díaz-Valdés, Marta; Wanner, Gerhard; Ramos-Esplá, Alfonso; Dubilier, Nicole; Antón, Josefa

    2008-11-01

    Marine Crenarchaeota represent an abundant component of the oceanic microbiota that play an important role in the global nitrogen cycle. Here we report the association of the colonial ascidian Cystodytes dellechiajei with putative ammonia-oxidizing Crenarchaeota that could actively be involved in nitrification inside the animal tissue. As shown by 16S rRNA gene analysis, the ascidian-associated Crenarchaeota were phylogenetically related to Nitrosopumilus maritimus, the first marine archaeon isolated in pure culture that grows chemolithoautotrophically oxidizing ammonia to nitrite aerobically. Catalysed reporter deposition (CARD)-FISH revealed that the Crenarchaeota were specifically located inside the tunic tissue of the colony, where moreover the expression of amoA gene was detected. The amoA gene encodes the alpha-subunit of ammonia monooxygenase, which is involved in the first step of nitrification, the oxidation of ammonia to nitrite. Sequencing of amoA gene showed that they were phylogenetically related to amoA genes of N. maritimus and other putative ammonia-oxidizing marine Crenarchaeota. In order to track the suspected nitrification activity inside the ascidian colony under in vivo conditions, microsensor profiles were measured through the tunic tissue. Net NO(x) production was detected in the tunic layer 1200-1800 microm with rates of 58-90 nmol cm(-3) h(-1). Oxygen and pH microsensor profiles showed that the layer of net NO(x) production coincided with O(2) concentrations of 103-116 microM and pH value of 5.2. Together, molecular and microsensor data indicate that Crenarchaeota could oxidize ammonia to nitrite aerobically, and thus be involved in nitrification inside the ascidian tissue.

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

    PubMed

    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.

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

    PubMed Central

    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

  10. Cockles, barnacles and ascidians compose a subtidal facilitation cascade with multiple hierarchical levels of foundation species.

    PubMed

    Yakovis, Eugeniy; Artemieva, Anna

    2017-03-22

    Facilitation cascades occur when multiple foundation species in a community are involved in a hierarchy of positive interactions, and consist of a primary facilitator which positively affects secondary facilitators, each supporting a suit of dependent species. There is no theoretical limit to the number of levels in a facilitation cascade, yet the existence of more than two has rarely been examined. We manipulated biogenic substrate produced by a primary facilitator (cockle shells) and a secondary facilitator (barnacles and their empty tests) in a space-limited subtidal community to test the hypothesis that solitary ascidians would be the third-level facilitator. In the field, most ascidians were found on barnacles, and most barnacles occupied cockle shells. To produce this pattern, barnacles could nurse ascidians (a longer 'facilitation chain') or outcompete them from cockle shells (a shorter chain). Experimental results clearly supported the nursing hypothesis providing evidence for a facilitation cascade with three hierarchical levels of foundation species. Our findings confirm that like predation and competition, positive interspecific interactions nest into multi-tier hierarchies with numerous levels. While the number of foundation species should increase community stability and resilience as it increases diversity and reduces environmental stress, facilitation chain length may have the opposite effect.

  11. Gut-spilling in chordates: Evisceration in the tropical ascidian Polycarpa mytiligera

    PubMed Central

    Shenkar, Noa; Gordon, Tal

    2015-01-01

    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. PMID:25880620

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

    PubMed

    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.

  13. Matrix adhesion polarizes heart progenitor induction in the invertebrate chordate Ciona intestinalis.

    PubMed

    Norton, Jennifer; Cooley, James; Islam, A F M Tariqul; Cota, Christina D; Davidson, Brad

    2013-03-01

    Cell-matrix adhesion strongly influences developmental signaling. Resulting impacts on cell migration and tissue morphogenesis are well characterized. However, the in vivo impact of adhesion on fate induction remains ambiguous. Here, we employ the invertebrate chordate Ciona intestinalis to delineate an essential in vivo role for matrix adhesion in heart progenitor induction. In Ciona pre-cardiac founder cells, invasion of the underlying epidermis promotes localized induction of the heart progenitor lineage. We found that these epidermal invasions are associated with matrix adhesion along the pre-cardiac cell/epidermal boundary. Through targeted manipulations of RAP GTPase activity, we were able to manipulate pre-cardiac cell-matrix adhesion. Targeted disruption of pre-cardiac cell-matrix adhesion blocked heart progenitor induction. Conversely, increased matrix adhesion generated expanded induction. We were also able to selectively restore cell-matrix adhesion and heart progenitor induction through targeted expression of Ci-Integrin β2. These results indicate that matrix adhesion functions as a necessary and sufficient extrinsic cue for regional heart progenitor induction. Furthermore, time-lapse imaging suggests that cytokinesis acts as an intrinsic temporal regulator of heart progenitor adhesion and induction. Our findings highlight a potentially conserved role for matrix adhesion in early steps of vertebrate heart progenitor specification.

  14. Expression of neuropeptide- and hormone-encoding genes in the Ciona intestinalis larval brain.

    PubMed

    Hamada, Mayuko; Shimozono, Naoki; Ohta, Naoyuki; Satou, Yutaka; Horie, Takeo; Kawada, Tsuyoshi; Satake, Honoo; Sasakura, Yasunori; Satoh, Nori

    2011-04-15

    Despite containing only approximately 330 cells, the central nervous system (CNS) of Ciona intestinalis larvae has an architecture that is similar to the vertebrate CNS. Although only vertebrates have a distinct hypothalamus-the source of numerous neurohormone peptides that play pivotal roles in the development, function, and maintenance of various neuronal and endocrine systems, it is suggested that the Ciona brain contains a region that corresponds to the vertebrate hypothalamus. To identify genes expressed in the brain, we isolated brain vesicles using transgenic embryos carrying Ci-β-tubulin(promoter)::Kaede, which resulted in robust Kaede expression in the larval CNS. The associated transcriptome was investigated using microarray analysis. We identified 565 genes that were preferentially expressed in the larval brain. Among these genes, 11 encoded neurohormone peptides including such hypothalamic peptides as gonadotropin-releasing hormone and oxytocin/vasopressin. Six of the identified peptide genes had not been previously described. We also found that genes encoding receptors for some of the peptides were expressed in the brain. Interestingly, whole-mount in situ hybridization showed that most of the peptide genes were expressed in the ventral brain. This catalog of the genes expressed in the larval brain should help elucidate the evolution, development, and functioning of the chordate brain.

  15. Immune competence of the Ciona intestinalis pharynx: complement system-mediated activity.

    PubMed

    Giacomelli, Stefano; Melillo, Daniela; Lambris, John D; Pinto, Maria Rosaria

    2012-10-01

    In the tunicate Ciona intestinalis, the ciliated pharynx, which connects the external environment to a highly developed and compartmentalized gastrointestinal system, represents the natural portal of entry for a vast and diverse, potentially pathogenic microbial community. To address the role of the pharynx in immune surveillance in Ciona, we asked whether C3, the key component of the complement system, was expressed in this organ and whether the encoded protein was functionally active. We found by real-time PCR that C3, constitutively expressed in the pharynx, is up-regulated by LPS injection. Using two specific anti-CiC3 and anti-CiC3a polyclonal antibodies in immunohistochemical staining of pharynx sections, we found that the gene product was localized to hemocytes of the pharyngeal bars (identified as granular amoebocytes) and in stigmata ciliated cells. Use of the same antibodies in Western blot analysis indicated that CiC3 and its activation products CiC3b and CiC3a are present in pharynx homogenates. Our observation that the amount of the bioactive fragment CiC3a increased in the pharynx of LPS-treated animals provides the first molecular and functional evidence for complement-mediated immunological activity in the tunicate pharynx.

  16. Familial Mediterranean Fever

    MedlinePlus

    Diseases and Conditions Familial Mediterranean fever By Mayo Clinic Staff Familial Mediterranean fever is an inflammatory disorder that causes recurrent fevers and painful inflammation of your abdomen, ...

  17. Investigating sperm cryopreservation in a model tunicate, Ciona intestinalis sp. A.

    PubMed

    Sorrenti, Gerarda; Bagnoli, Anna; Miraglia, Valentina; Crocetta, Fabio; Vitiello, Valentina; Ristoratore, Filomena; Cirino, Paola; Sansone, Giovanni; Sordino, Paolo

    2014-02-01

    In cryopreservation procedures, the capacity to protect the cells from freezing and thawing processes is sensitive to the choice of the cryoprotective agent (CPA) and to its optimal concentration. The advancement of research on Tunicate model species has raised interest in liquid nitrogen cryopreservation for the storage and distribution of genetic resources. Ciona intestinalis (Linnè, 1767) consists of a complex of cryptic taxa that are central to several areas of investigation, from comparative genomics to invasive biology. Here we investigated how five CPAs, three chilling rates and two freezing rates influence semen cryopreservation in C. intestinalis sp. A. By using larval morphology and motility as endpoints, we estimated that long term semen storage requires 10% dimethyl sulfoxide as a protective agent, -1°C/min chilling rate (18°C to 5°C) and -13°C/min freezing rate (5°C to -80°C), followed by immersion in liquid nitrogen.

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

    SciTech Connect

    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.

    PubMed

    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. Dynamic changes in developmental gene expression in the basal chordate Ciona intestinalis.

    PubMed

    Kawashima, Takeshi; Satou, Yutaka; Murakami, Seiko D; Satoh, Nori

    2005-04-01

    Large-scale expressed sequence tags (EST) analysis was used to demonstrate a number of dynamic changes in the global gene expression profile of the basal chordate Ciona intestinalis over the course of its development. The fertilized egg was found to store a great variety of maternal transcripts and, as development proceeds, the organism expresses a progressively smaller repertoire of genes. In addition, a significant portion of genes involved in embryogenesis were observed to be downregulated during metamorphosis, at which point the adult appears to utilize a different set of genes to form its body. At least 25% of the genes involved in development were found to be used multiple times. This kind of information is essential to form a comprehensive understanding of the overarching expression-control plan by which the basic chordate body is formed.

  1. Arsenic (+ 3 oxidation state) methyltransferase and the methylation of arsenicals in the invertebrate chordate Ciona intestinalis.

    PubMed

    Thomas, David J; Nava, Gerardo M; Cai, Shi-Ying; Boyer, James L; Hernández-Zavala, Araceli; Gaskins, H Rex

    2010-01-01

    Biotransformation of inorganic arsenic (iAs) involves methylation catalyzed by arsenic (+ 3 oxidation state) methyltransferase (As3mt) yielding mono-, di-, and trimethylated arsenicals. To investigate the evolution of molecular mechanisms that mediate arsenic biotransformation, a comparative genomic approach focusing on the invertebrate chordate Ciona intestinalis was used. Bioinformatic analyses identified an As3mt gene in the C. intestinalis genome. Constitutive As3mt RNA expression was observed in heart, branchial sac, and gastrointestinal tract. Adult animals were exposed to 0 or 1 ppm of iAs for 1 or 5 days. Steady-state As3mt RNA expression in the gastrointestinal tract was not modulated significantly by 5 days of exposure to iAs. Tissue levels of iAs and its methylated metabolites were determined by hydride generation-cryotrapping-gas chromatography-atomic absorption spectrometry. At either time point, exposure to iAs significantly increased concentrations of iAs and its methylated metabolites in tissues. After 5 days of exposure, total speciated arsenic concentrations were highest in branchial sac (3705 ng/g), followed by heart (1019 ng/g) and gastrointestinal tract (835 ng/g). At this time point, the sum of the speciated arsenical concentrations in gastrointestinal tract and heart equaled or exceeded that of iAs; in branchial sac, iAs was the predominant species present. Ciona intestinalis metabolizes iAs to its methylated metabolites, which are retained in tissues. This metabolic pattern is consistent with the presence of an As3mt ortholog in its genome and constitutive expression of the gene in prominent organs, making this basal chordate a useful model to examine the evolution of arsenic detoxification.

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

    PubMed

    Ueda, Nobuo; Degnan, Sandie M

    2013-01-01

    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 in ascidian

  3. Nitric Oxide Acts as a Positive Regulator to Induce Metamorphosis of the Ascidian Herdmania momus

    PubMed Central

    Ueda, Nobuo; Degnan, Sandie M.

    2013-01-01

    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 in ascidian

  4. The alien ascidian Styela clava now invading the Sea of Marmara (Tunicata: Ascidiacea)

    PubMed Central

    Çinar, Melih Ertan

    2016-01-01

    Abstract During the implementation of a large project aimed to investigate the benthic community structures of the Sea of Marmara, specimens of the invasive ascidian species Styela clava were collected on natural substrata (rocks) at 10 m depth at one locality (Karamürsel) in İzmit Bay. The specimens were mature, containing gametes, indicating that the species had become established in the area. The Sea of Marmara seems to provide suitable conditions for this species to survive and form proliferating populations. PMID:27047235

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

    PubMed

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

    PubMed Central

    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. PMID:26668163

  7. Population dynamics of the solitary ascidian Herdmania momus (Savignyi, 1816) in Jeju Island, Korea

    NASA Astrophysics Data System (ADS)

    Yi, Chang Ho; Kim, Jeong Ha

    2016-09-01

    In 2007-2008, a population outbreak of the solitary ascidian Herdmania momus was observed along the coasts of Jeju Island and the ascidians became the top dominant species in macrobenthic communities. We conducted field experiments on population dynamics and demographic parameters including seasonal density fluctuation, vertical distribution, recruitment patterns, mortality, and growth rate. Recruitment continued year-round except in April following the lowest water temperature season in February. Population density was highest in August-October, concomitantly with the peak in recruitment, related to the highest water temperature. The lowest density was observed in February-April when the water temperature was lowest. In April all individuals disappeared from all permanent plots, resulting in a maximum life span of 10-12 months. Individuals of newly recruited H. momus grew to have an adult size of 4-6 cm in only 3-4 months. Higher densities were observed in the shallower areas (5 m) compared to the deeper zones. More recruitment occurred on vertical slopes than horizontal substrates, but substrate pre-occupancy caused no difference in recruitment. This is the first report on H. momus population-level investigation in Korea, which provides valuable baseline information on the current status of population demography and their potential community-level influence on Jeju coasts.

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

    PubMed

    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.

  9. Neurula rotation determines left-right asymmetry in ascidian tadpole larvae.

    PubMed

    Nishide, Kazuhiko; Mugitani, Michio; Kumano, Gaku; Nishida, Hiroki

    2012-04-01

    Tadpole larvae of the ascidian Halocynthia roretzi show morphological left-right asymmetry. The tail invariably bends towards the left side within the vitelline membrane. The structure of the larval brain is remarkably asymmetric. nodal, a conserved gene that shows left-sided expression, is also expressed on the left side in H. roretzi but in the epidermis unlike in vertebrates. We show that nodal signaling at the late neurula stage is required for stereotypic morphological left-right asymmetry at later stages. We uncover a novel mechanism to break embryonic symmetry, in which rotation of whole embryos provides the initial cue for left-sided expression of nodal. Two hours prior to the onset of nodal expression, the neurula embryo rotates along the anterior-posterior axis in a counterclockwise direction when seen in posterior view, and then this rotation stops when the left side of the embryo is oriented downwards. It is likely that epidermis monocilia, which appear at the neurula rotation stage, generate the driving force for the rotation. When the embryo lies on the left side, protrusion of the neural fold physically prevents it from rotating further. Experiments in which neurula rotation is perturbed by various means, including centrifugation and sandwiching between glass, indicate that contact of the left epidermis with the vitelline membrane as a consequence of neurula rotation promotes nodal expression in the left epidermis. We suggest that chemical, and not mechanical, signals from the vitelline membrane promote nodal expression. Neurula rotation is also conserved in other ascidian species.

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

    PubMed

    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.

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

    PubMed

    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.

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

    PubMed

    Hebras, Celine; McDougall, Alex

    2012-01-01

    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 in eggs and

  13. Bacterial diversity associated with the tunic of the model chordate Ciona intestinalis

    PubMed Central

    Blasiak, Leah C; Zinder, Stephen H; Buckley, Daniel H; Hill, Russell T

    2014-01-01

    The sea squirt Ciona intestinalis is a well-studied model organism in developmental biology, yet little is known about its associated bacterial community. In this study, a combination of 454 pyrosequencing of 16S ribosomal RNA genes, catalyzed reporter deposition-fluorescence in situ hybridization and bacterial culture were used to characterize the bacteria living inside and on the exterior coating, or tunic, of C. intestinalis adults. The 454 sequencing data set demonstrated that the tunic bacterial community structure is different from that of the surrounding seawater. The observed tunic bacterial consortium contained a shared community of <10 abundant bacterial phylotypes across three individuals. Culture experiments yielded four bacterial strains that were also dominant groups in the 454 sequencing data set, including novel representatives of the classes Alphaproteobacteria and Flavobacteria. The relatively simple bacterial community and availability of dominant community members in culture make C. intestinalis a promising system in which to investigate functional interactions between host-associated microbiota and the development of host innate immunity. PMID:24048225

  14. Bacterial diversity associated with the tunic of the model chordate Ciona intestinalis.

    PubMed

    Blasiak, Leah C; Zinder, Stephen H; Buckley, Daniel H; Hill, Russell T

    2014-02-01

    The sea squirt Ciona intestinalis is a well-studied model organism in developmental biology, yet little is known about its associated bacterial community. In this study, a combination of 454 pyrosequencing of 16S ribosomal RNA genes, catalyzed reporter deposition-fluorescence in situ hybridization and bacterial culture were used to characterize the bacteria living inside and on the exterior coating, or tunic, of C. intestinalis adults. The 454 sequencing data set demonstrated that the tunic bacterial community structure is different from that of the surrounding seawater. The observed tunic bacterial consortium contained a shared community of <10 abundant bacterial phylotypes across three individuals. Culture experiments yielded four bacterial strains that were also dominant groups in the 454 sequencing data set, including novel representatives of the classes Alphaproteobacteria and Flavobacteria. The relatively simple bacterial community and availability of dominant community members in culture make C. intestinalis a promising system in which to investigate functional interactions between host-associated microbiota and the development of host innate immunity.

  15. Molecular characterisation, evolution and expression analysis of g-type lysozymes in Ciona intestinalis.

    PubMed

    Di Falco, Felicia; Cammarata, Matteo; Vizzini, Aiti

    2017-02-01

    Lysozyme is an important defense molecule of the innate immune system. Known for its bactericidal properties, lysozyme catalyzes the hydrolysis of b-(1,4)-glycosidic bonds between the N-acetyl glucosamine and N-acetyl muramic acid in the peptidoglycan layer of bacterial cell walls. In this study, the complete coding sequence of four g-type lysozymes were identified in Ciona intestinalis. Phylogenetic analysis and modelling supported the hypothesis of a close relationship with the vertebrate g-type lysozymes suggesting that the C. intestinalis g-type lysozyme genes (CiLys-g1, Cilys-g2, CiLys-g3, CiLys-g4) share a common ancestor in the chordate lineage. Protein motif searches indicated that C. intestinalis g-type lysozymes contain a GEWL domain with a GXXQ signature, typical of goose lysozymes. Quantitative Real-Time PCR analysis results showed that transcripts are expressed in various tissues from C. intestinalis. In order to determine the involvement of C. intestinalis g-type lysozymes in immunity, their expression was analyzed in the pharynx, showing that transcripts were significantly up-regulated in response to a challenge with lipopolysaccharide (LPS). These data support the view that CiLys g-type are molecules with potential for immune defense system against bacterial infection.

  16. Isolation of a novel LPS-induced component of the ML superfamily in Ciona intestinalis.

    PubMed

    Vizzini, Aiti; Bonura, Angela; Longo, Valeria; Sanfratello, Maria Antonietta; Parrinello, Daniela; Cammarata, Matteo; Colombo, Paolo

    2015-11-01

    ML superfamily represents a group of proteins playing important roles in lipid metabolism and innate immune response. In this study, we report the identification of the first component of the ML superfamily in the invertebrate Ciona intestinalis by means of a subtractive hybridization strategy. Sequence homology and phylogenetic analysis showed that this protein forms a specific clade with vertebrate components of the Niemann-Pick type C2 protein and, for this reason, it has been named Ci-NPC2. The putative Ci-NPC2 is a 150 amino acids long protein with a short signal peptide, seven cysteine residues, three putative lipid binding site and a three-dimensional model showing a characteristic β-strand structure. Gene expression analysis demonstrated that the Ci-NPC2 protein is positively upregulated after LPS inoculum with a peak of expression 1 h after challenge. Finally, in-situ hybridization demonstrated that the Ci-NPC2 protein is preferentially expressed in hemocytes inside the vessel lumen.

  17. Mining antimicrobial peptides from small open reading frames in Ciona intestinalis.

    PubMed

    Lu, Yongzhong; Zhuang, Yu; Liu, Jie

    2014-01-01

    Though being able to encode various kinds of bioactive peptides, small open reading frames (sORFs) are poorly annotated in many genomic data. The present study was conducted to evaluate the potential of sORFs in encoding antimicrobial peptides (AMPs) in the basal chordate model Ciona intestinalis. About 4.8 m genomic sequence was first retrieved for sORFs mining by the program sORF finder, then the sORFs were translated into amino acid sequences for AMP prediction via CAMP server, and thereafter, ten putative AMPs were selected for expression and antimicrobial activity validation. In total, over 180 peptides deduced from the sORFs were predicted to be AMPs. Among the ten tested peptides, six were found to have significant expressed sequence tag matches, providing strong evidence for gene expression; five were proved to be active against the bacterial strains. These results indicate that many sORFs in C. intestinalis genome contain AMP information. This work can serve as an important initial step to investigate the role of sORFs in the innate defense of C. intestinalis.

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

    PubMed

    Nakamura, Mitsuru J; Hotta, Kohji; Oka, Kotaro

    2013-01-01

    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.

  19. Differential gene expression in notochord and nerve cord fate segregation in the Ciona intestinalis embryo.

    PubMed

    Kobayashi, Kenji; Yamada, Lixy; Satou, Yutaka; Satoh, Nori

    2013-09-01

    During early embryogenesis, embryonic cells gradually restrict their developmental potential and are eventually destined to give rise to one type of cells. Molecular mechanisms underlying developmental fate restriction are one of the major research subjects within developmental biology. In this article, this subject was addressed by combining blastomere isolation with microarray analysis. During the 6th cleavage of the Ciona intestinalis embryo, from the 32-cell to the 64-cell stage, four mother cells divide into daughter cells with two distinct fates, one giving rise to notochord precursor cells and the other to nerve cord precursors. Approximately 2,200 each of notochord and nerve cord precursor cells were isolated, and their mRNA expression profiles were compared by microarray. This analysis identified 106 and 68 genes, respectively, that are differentially expressed in notochord and nerve cord precursor cells. These included not only genes for transcription factors and signaling molecules but also those with generalized functions observed in many types of cells. In addition, whole-mount in situ hybridization showed dynamic spatial expression profiles of these genes during segregation of the two fates: partitioning of transcripts present in the mother cells into either type of daughter cells, and initiation of preferential gene expression in either type of cells.

  20. Regeneration, Stem Cells, and Aging in the Tunicate Ciona: Insights from the Oral Siphon.

    PubMed

    Jeffery, William R

    2015-01-01

    Regeneration studies in the tunicate Ciona intestinalis have recently been focused on the potential of adult stem cells to replace injured tissues and organs during the adult life cycle using the oral siphon (OS) as a model. The OS has oral siphon pigment organs (OPOs) along its rim and an underlying network of muscle fibers in its tube. Different regeneration processes are triggered by OS amputation at the tip, along the tube, or at the base. One process involves the replacement of OPOs without new cell division by direct differentiation of locally deployed stem cells or stem cells that migrate from the branchial sac. Another process involves blastema formation by the migration of progenitor cells produced from branchial sac stem cells. The capacity for complete and accurate OS regeneration declines continuously during the adult life cycle. Finally, after an age threshold is reached, OS regeneration ceases in old animals. The loss of regeneration capacity in old animals involves the depletion of stem cells in the branchial sac, the inability of branchial sac progenitor cells to migrate to the sites of regeneration, and defective oral pigment organ replacement. The significance of the OS model for studying regeneration, stem cells, and aging will be enhanced by the application of molecular methods.

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

    PubMed Central

    Chen, Xiaoshuang; Xu, Huanli; Li, Bo; Wang, Feng; Chen, Xiaoliang; Kong, Dexin; Lin, Xiukun

    2016-01-01

    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. PMID:27007382

  2. [Distribution and abundance of the ascidian Ecteinascidia turbinata (Ascidiacea: Perophoridae) in Cuba].

    PubMed

    Hernández-Zanuy, Aida; Carballo, José Luis; García-Cagide, Alida; Naranjo, Santiago; Esquivel, Macario

    2007-03-01

    Permanently submerged mangrove roots (Rhizophora mangle) are the main habitat of the ascidian Ecteinascidia turbinata in Cuba. It was occasionally found on black coral (Antiphates caribeana) between 22 and 38 meters deep. This species exhibits a wide distribution in all the mangrove keys surrounding the Island of Cuba but does not occur in riparian or fringing mangroves. Populations of this species are abundant in Cuba: in 75% of the 58 localities sampled the species was present and in 57% more than 50% of the roots held at least one colony. The highest colony densities were found in the northern coast of Pinar del Rio province with values near one colony per lineal meter of mangrove root. We found the highest density (1.46 col/m) and greatest biomass at Jutías Key, with values between 25 and 660 g/m. The average of wet biomass in the studied mangroves was 73.63 g/m.

  3. Ultrastructures and classification of circulating hemocytes in 9 botryllid ascidians (chordata: ascidiacea).

    PubMed

    Hirose, Euichi; Shirae, Maki; Saito, Yasunori

    2003-05-01

    Ultrastructures of circulating hemocytes were studied in 9 botryllid ascidians. The hemocytes are classified into five types: hemoblasts, phagocytes, granulocytes, morula cells, and pigment cells. These five types are always found in the 9 species. They should represent the major hemocyte types of the circulating cells in the blood. Hemoblasts are small hemocytes having a high nucleus/cytoplasm ratio. There are few granular or vacuolar inclusions in the cytoplasm. Phagocytes have phagocytic activity and their shape is variable depending on the amount of engulfed materials. In granulocytes, shape and size of granules are different among the species. Morula cells are characterized by several vacuoles filled with electron dense materials. In pigment cells, the bulk of the cytoplasm is occupied by one or a few vacuoles containing pigment granules. We also described some other hemocyte types found in particular species. Furthermore, we encountered free oocytes circulating in the blood in two species, Botryllus primigenus and Botrylloides lentus.

  4. Experimental allometry: effect of size manipulation on metabolic rate of colonial ascidians

    PubMed Central

    Nakaya, Fumio; Saito, Yasunori; Motokawa, Tatsuo

    2005-01-01

    The allometric scaling of metabolic rate of organisms, the three-quarters power rule, has led to a questioning of the basis for the relation. We attacked this problem experimentally for the first time by employing the modular organism, the ascidian that forms a single layered flat colony, as a model system. The metabolic rate and colony size followed the three-quarters power relation, which held even after the colony size was experimentally manipulated. Our results established that the three-quarters power relation is a real continuous function, not an imaginary statistical regression. The fact that all the hypotheses failed to explain why the two-dimensional organism adhered to the three-quarters power relation led us to propose a new hypothesis, in which the allometric relation derives from the self-organized criticality based on local interaction between modulus-comprising organisms. PMID:16191604

  5. The development of three identified motor neurons in the larva of an ascidian, Halocynthia roretzi.

    PubMed

    Okada, Toshiaki; Katsuyama, You; Ono, Fumihito; Okamura, Yasushi

    2002-04-15

    The generation of distinct classes of motor neurons underlies the development of complex motile behavior in all animals and is well characterized in chordates. Recent molecular studies indicate that the ascidian larval central nervous system (CNS) exhibits anteroposterior regionalization similar to that seen in the vertebrate CNS. To extend the understanding about the diversity of motor neurons in the ascidian larva, we have identified the number, position, and projection of individual motor neurons in Halocynthia roretzi, using a green fluorescent protein under the control of a neuron-specific promoter. Three pairs of motor neurons, each with a distinct shape and innervation pattern, were identified along the anteroposterior axis of the neural tube: the anterior and posterior pairs extend their axons toward dorsal muscle cells, whereas the middle pair project their axons toward ventral muscle. Overexpression of a dominant-negative form of a potassium channel in these cells resulted in paralysis on the injected side, thus these cells must constitute the major population of motor neurons responsible for swimming behavior. Lim class homeobox genes have been known as candidate genes that determine subtypes of motor neurons. Therefore, the expression pattern of Hrlim, which is a Lim class homeobox gene, was examined in the motor neuron precursors. All three motor neurons expressed Hrlim at the tailbud stage, although each down-regulated Hrlim at a different time. Misexpression of Hrlim in the epidermal lineage led to ectopic expression of TuNa2, a putative voltage-gated channel gene normally expressed predominantly in the three pairs of motor neurons. Hrlim may control membrane excitability of motor neurons by regulating ion channel gene expression.

  6. Antagonizing retinoic acid and FGF/MAPK pathways control posterior body patterning in the invertebrate chordate Ciona intestinalis.

    PubMed

    Pasini, Andrea; Manenti, Raoul; Rothbächer, Ute; Lemaire, Patrick

    2012-01-01

    Vertebrate embryos exploit the mutual inhibition between the RA and FGF signalling pathways to coordinate the proliferative elongation of the main body axis with the progressive patterning and differentiation of its neuroectodermal and paraxial mesodermal structures. The evolutionary history of this patterning system is still poorly understood. Here, we investigate the role played by the RA and FGF/MAPK signals during the development of the tail structures in the tunicate Ciona intestinalis, an invertebrate chordate belonging to the sister clade of vertebrates, in which the prototypical chordate body plan is established through very derived morphogenetic processes. Ciona embryos are constituted of few cells and develop according to a fixed lineage; elongation of the tail occurs largely by rearrangement of postmitotic cells; mesoderm segmentation and somitogenesis are absent. We show that in the Ciona embryo, the antagonism of the RA and FGF/MAPK signals is required to control the anteroposterior patterning of the tail epidermis. We also demonstrate that the RA, FGF/MAPK and canonical Wnt pathways control the anteroposterior patterning of the tail peripheral nervous system, and reveal the existence of distinct subpopulations of caudal epidermal neurons with different responsiveness to the RA, FGF/MAPK and canonical Wnt signals. Our data provide the first demonstration that the use of the antagonism between the RA and FGF signals to pattern the main body axis predates the emergence of vertebrates and highlight the evolutionary plasticity of this patterning strategy, showing that in different chordates it can be used to pattern different tissues within the same homologous body region.

  7. Antagonizing Retinoic Acid and FGF/MAPK Pathways Control Posterior Body Patterning in the Invertebrate Chordate Ciona intestinalis

    PubMed Central

    Pasini, Andrea; Manenti, Raoul; Rothbächer, Ute; Lemaire, Patrick

    2012-01-01

    Vertebrate embryos exploit the mutual inhibition between the RA and FGF signalling pathways to coordinate the proliferative elongation of the main body axis with the progressive patterning and differentiation of its neuroectodermal and paraxial mesodermal structures. The evolutionary history of this patterning system is still poorly understood. Here, we investigate the role played by the RA and FGF/MAPK signals during the development of the tail structures in the tunicate Ciona intestinalis, an invertebrate chordate belonging to the sister clade of vertebrates, in which the prototypical chordate body plan is established through very derived morphogenetic processes. Ciona embryos are constituted of few cells and develop according to a fixed lineage; elongation of the tail occurs largely by rearrangement of postmitotic cells; mesoderm segmentation and somitogenesis are absent. We show that in the Ciona embryo, the antagonism of the RA and FGF/MAPK signals is required to control the anteroposterior patterning of the tail epidermis. We also demonstrate that the RA, FGF/MAPK and canonical Wnt pathways control the anteroposterior patterning of the tail peripheral nervous system, and reveal the existence of distinct subpopulations of caudal epidermal neurons with different responsiveness to the RA, FGF/MAPK and canonical Wnt signals. Our data provide the first demonstration that the use of the antagonism between the RA and FGF signals to pattern the main body axis predates the emergence of vertebrates and highlight the evolutionary plasticity of this patterning strategy, showing that in different chordates it can be used to pattern different tissues within the same homologous body region. PMID:23049976

  8. Diiron centre mutations in Ciona intestinalis alternative oxidase abolish enzymatic activity and prevent rescue of cytochrome oxidase deficiency in flies.

    PubMed

    Andjelković, Ana; Oliveira, Marcos T; Cannino, Giuseppe; Yalgin, Cagri; Dhandapani, Praveen K; Dufour, Eric; Rustin, Pierre; Szibor, Marten; Jacobs, Howard T

    2015-12-17

    The mitochondrial alternative oxidase, AOX, carries out the non proton-motive re-oxidation of ubiquinol by oxygen in lower eukaryotes, plants and some animals. Here we created a modified version of AOX from Ciona instestinalis, carrying mutations at conserved residues predicted to be required for chelation of the diiron prosthetic group. The modified protein was stably expressed in mammalian cells or flies, but lacked enzymatic activity and was unable to rescue the phenotypes of flies knocked down for a subunit of cytochrome oxidase. The mutated AOX transgene is thus a potentially useful tool in studies of the physiological effects of AOX expression.

  9. Molecular and morphological discrimination between an invasive ascidian, Ascidiella aspersa, and its congener A. scabra (Urochordata: Ascidiacea).

    PubMed

    Nishikawa, Teruaki; Oohara, Ichiro; Saitoh, Kenji; Shigenobu, Yuya; Hasegawa, Natsuki; Kanamori, Makoto; Baba, Katsuhisa; Turon, Xavier; Bishop, John D D

    2014-03-01

    The solitary ascidian Ascidiella aspersa (Müller, 1776) has sometimes been regarded as conspecific with A. scabra (Müller, 1776), although previous detailed morphological comparisons have indicated that the two are distinguishable by internal structures. Resolution of this taxonomic issue is important because A. aspersa has been known as a notoriously invasive ascidian, doing much damage to aquaculture e.g. in Hokkaido, Japan. We collected many specimens from European waters (including the Swedish coast, near the type localities of these two species) and Hokkaido, Japan (as an alien population) and made molecular phylogenetic analyses using the mitochondrial cytochrome c oxidase subunit I (COI) gene, and found that in terms of COI sequences all the analyzed specimens were clustered into two distinct groups, one of which is morphologically referable to A. aspersa and the other to A. scabra. Thus, these two species should be regarded as distinct from each other.

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

    PubMed Central

    Kühl, Michael; Behrendt, Lars; Trampe, Erik; Qvortrup, Klaus; Schreiber, Ulrich; Borisov, Sergey M.; Klimant, Ingo; Larkum, Anthony W. D.

    2012-01-01

    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 minutes of darkness, while the same zone exhibited O2 super-saturation and strongly alkaline pH after a few minutes 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. PMID:23226144

  11. Isolation of an early neural maker gene abundantly expressed in the nervous system of the ascidian, Halocynthia roretzi.

    PubMed

    Yagi, K; Makabe, K W

    2001-01-01

    Ascidian tadpole larvae possess a primitive nervous system, which is a prospective prototype of the chordate nervous system. It is composed of relatively few cells but sufficient for complex larval behavior. Here we report on HrETR-1, a gene zygotically expressed in a large proportion of the developing neural cells of the ascidian, Halocynthia roretzi. HrETR-1 is an early neural marker which can be used for analyzing neural differentiation. HrETR-1 expression intensified in most neural cells of genes isolated to date, in both central and peripheral nervous systems including palps as early as the 110-cell stage. Using this gene as a probe, we characterized neural cells in the nervous system as well as confirming their origins. Also, we recognized three types of peripheral epidermal neurons which presumably correlate to the larval neurons previously reported for another ascidian. Among these, five bilateral neurons located in the anterior region of the trunk appeared to be derived from a8.26 blastomeres.

  12. Efficient targeted mutagenesis of the chordate Ciona intestinalis genome with zinc-finger nucleases.

    PubMed

    Kawai, Narudo; Ochiai, Hiroshi; Sakuma, Tetsushi; Yamada, Lixy; Sawada, Hitoshi; Yamamoto, Takashi; Sasakura, Yasunori

    2012-06-01

    Zinc-finger nucleases (ZFNs) are engineered nucleases that induce DNA double-strand breaks (DSBs) at target sequences. They have been used as tools for generating targeted mutations in the genomes of multiple organisms in both animals and plants. The DSB induced by ZFNs is repaired by non-homologous end joining (NHEJ) or by homologous recombination (HR) mechanisms. Non-homologous end joining induces some errors because it is independent of a reference DNA sequence. Through the NHEJ mechanism, ZFNs generate insertional or deletional mutations at the target sequence. We examined the usability, specificity and toxicity of ZFNs in the basal chordate Ciona intestinalis. As the target of ZFNs, we chose an enhanced green fluorescent protein (EGFP) gene artificially inserted in the C. intestinalis genome because this locus is neutral for the development and growth of C. intestinalis, and the efficiency of mutagenesis with ZFNs can thus be determined without any bias. We introduced EGFP -ZFN mRNAs into the embryos of an EGFP -transgenic line and observed the mutation frequency in the target site of EGFP . We also examined the effects of the EGFP -ZFNs at off-target sites resembling the EGFP target sequence in the C. intestinalis genome in order to examine the specificity of ZFNs. We further investigated the influence of ZFNs on embryogenesis, and showed that adequate amounts of ZFNs, which do not disrupt embryogenesis, can efficiently induce mutations on the on-target site with less effect on the off-target sites. This suggests that target mutagenesis with ZFNs will be a powerful technique in C. intestinalis.

  13. Crossing the species barrier: genomic hotspots of introgression between two highly divergent Ciona intestinalis species.

    PubMed

    Roux, Camille; Tsagkogeorga, Georgia; Bierne, Nicolas; Galtier, Nicolas

    2013-07-01

    Inferring a realistic demographic model from genetic data is an important challenge to gain insights into the historical events during the speciation process and to detect molecular signatures of selection along genomes. Recent advances in divergence population genetics have reported that speciation in face of gene flow occurred more frequently than theoretically expected, but the approaches used did not account for genome-wide heterogeneity (GWH) in introgression rates. Here, we investigate the impact of GWH on the inference of divergence with gene flow between two cryptic species of the marine model Ciona intestinalis by analyzing polymorphism and divergence patterns in 852 protein-coding sequence loci. These morphologically similar entities are highly diverged molecular-wise, but evidence of hybridization has been reported in both laboratory and field studies. We compare various speciation models and test for GWH under the approximate Bayesian computation framework. Our results demonstrate the presence of significant extents of gene flow resulting from a recent secondary contact after >3 My of divergence in isolation. The inferred rates of introgression are relatively low, highly variable across loci and mostly unidirectional, which is consistent with the idea that numerous genetic incompatibilities have accumulated over time throughout the genomes of these highly diverged species. A genomic map of the level of gene flow identified two hotspots of introgression, that is, large genome regions of unidirectional introgression. This study clarifies the history and degree of isolation of two cryptic and partially sympatric model species and provides a methodological framework to investigate GWH at various stages of speciation process.

  14. The Simple Chordate Ciona intestinalis Has a Reduced Complement of Genes Associated with Fanconi Anemia.

    PubMed

    Stanley, Edward C; Azzinaro, Paul A; Vierra, David A; Howlett, Niall G; Irvine, Steven Q

    2016-01-01

    Fanconi anemia (FA) is a human genetic disease characterized by congenital defects, bone marrow failure, and increased cancer risk. FA is associated with mutation in one of 24 genes. The protein products of these genes function cooperatively in the FA pathway to orchestrate the repair of DNA interstrand cross-links. Few model organisms exist for the study of FA. Seeking a model organism with a simpler version of the FA pathway, we searched the genome of the simple chordate Ciona intestinalis for homologs of the human FA-associated proteins. BLAST searches, sequence alignments, hydropathy comparisons, maximum likelihood phylogenetic analysis, and structural modeling were used to infer the likelihood of homology between C. intestinalis and human FA proteins. Our analysis indicates that C. intestinalis indeed has a simpler and potentially functional FA pathway. The C. intestinalis genome was searched for candidates for homology to 24 human FA and FA-associated proteins. Support was found for the existence of homologs for 13 of these 24 human genes in C. intestinalis. Members of each of the three commonly recognized FA gene functional groups were found. In group I, we identified homologs of FANCE, FANCL, FANCM, and UBE2T/FANCT. Both members of group II, FANCD2 and FANCI, have homologs in C. intestinalis. In group III, we found evidence for homologs of FANCJ, FANCO, FANCQ/ERCC4, FANCR/RAD51, and FANCS/BRCA1, as well as the FA-associated proteins ERCC1 and FAN1. Evidence was very weak for the existence of homologs in C. intestinalis for any other recognized FA genes. This work supports the notion that C. intestinalis, as a close relative of vertebrates, but having a much reduced complement of FA genes, offers a means of studying the function of certain FA proteins in a simpler pathway than that of vertebrate cells.

  15. The Simple Chordate Ciona intestinalis Has a Reduced Complement of Genes Associated with Fanconi Anemia

    PubMed Central

    Stanley, Edward C.; Azzinaro, Paul A.; Vierra, David A.; Howlett, Niall G.; Irvine, Steven Q.

    2016-01-01

    Fanconi anemia (FA) is a human genetic disease characterized by congenital defects, bone marrow failure, and increased cancer risk. FA is associated with mutation in one of 24 genes. The protein products of these genes function cooperatively in the FA pathway to orchestrate the repair of DNA interstrand cross-links. Few model organisms exist for the study of FA. Seeking a model organism with a simpler version of the FA pathway, we searched the genome of the simple chordate Ciona intestinalis for homologs of the human FA-associated proteins. BLAST searches, sequence alignments, hydropathy comparisons, maximum likelihood phylogenetic analysis, and structural modeling were used to infer the likelihood of homology between C. intestinalis and human FA proteins. Our analysis indicates that C. intestinalis indeed has a simpler and potentially functional FA pathway. The C. intestinalis genome was searched for candidates for homology to 24 human FA and FA-associated proteins. Support was found for the existence of homologs for 13 of these 24 human genes in C. intestinalis. Members of each of the three commonly recognized FA gene functional groups were found. In group I, we identified homologs of FANCE, FANCL, FANCM, and UBE2T/FANCT. Both members of group II, FANCD2 and FANCI, have homologs in C. intestinalis. In group III, we found evidence for homologs of FANCJ, FANCO, FANCQ/ERCC4, FANCR/RAD51, and FANCS/BRCA1, as well as the FA-associated proteins ERCC1 and FAN1. Evidence was very weak for the existence of homologs in C. intestinalis for any other recognized FA genes. This work supports the notion that C. intestinalis, as a close relative of vertebrates, but having a much reduced complement of FA genes, offers a means of studying the function of certain FA proteins in a simpler pathway than that of vertebrate cells. PMID:27279728

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

    PubMed

    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.

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

    PubMed

    Franchi, Nicola; Piccinni, Ester; Ferro, Diana; Basso, Giuseppe; Spolaore, Barbara; Santovito, Gianfranco; Ballarin, Loriano

    2014-07-01

    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 96h 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.

  18. A Maternal System Initiating the Zygotic Developmental Program through Combinatorial Repression in the Ascidian Embryo

    PubMed Central

    Oda-Ishii, Izumi; Kubo, Atsushi; Kari, Willi; Suzuki, Nobuhiro; Rothbächer, Ute

    2016-01-01

    Maternal factors initiate the zygotic developmental program in animal embryos. In embryos of the chordate, Ciona intestinalis, three maternal factors—Gata.a, β-catenin, and Zic-r.a—are required to establish three domains of gene expression at the 16-cell stage; the animal hemisphere, vegetal hemisphere, and posterior vegetal domains. Here, we show how the maternal factors establish these domains. First, only β-catenin and its effector transcription factor, Tcf7, are required to establish the vegetal hemisphere domain. Second, genes specifically expressed in the posterior vegetal domain have additional repressive cis-elements that antagonize the activity of β-catenin/Tcf7. This antagonizing activity is suppressed by Zic-r.a, which is specifically localized in the posterior vegetal domain and binds to DNA indirectly through the interaction with Tcf7. Third, Gata.a directs specific gene expression in the animal hemisphere domain, because β-catenin/Tcf7 weakens the Gata.a-binding activity for target sites through a physical interaction in the vegetal cells. Thus, repressive regulation through protein-protein interactions among the maternal transcription factors is essential to establish the first distinct domains of gene expression in the chordate embryo. PMID:27152625

  19. Vascular budding in Symplegma brakenhielmi and the evolution of coloniality in styelid ascidians.

    PubMed

    Gutierrez, Stefania; Brown, Federico D

    2017-03-15

    Individuals of colonial animals (e.g. zooids) are in continuous turnover. In ascidians colonial or solitary species have evolved by convergence multiple times. Colonial Botryllus and Botrylloides are well-studied genera that exhibit colony-wide developmental mechanisms that regulate synchronous and orchestrated cycles of budding and turnover of zooids. The origins of modular developmental mechanisms that facilitated the evolution of coloniality in this group remain unclear. To reconstruct ancestral states of coloniality we studied Symplegma brakenhielmi, a sister taxon of the botryllids. S. brakenhielmi zooids are embedded in a common tunic and present a similar vascular system as the botrylloides, however development and turnover of zooids occurs asynchronously and in a more independent manner. We generated a table of common stages of budding in Symplegma and Botryllus for comparative studies of asexual development. We tested dependent processes of budding among individuals of the colony by systemic bud or zooid removals. Although our results showed a higher degree of independence in bud development in S. brakenhielmi, we found a subtle colony-wide regulatory mechanism of modular development, i.e. new buds expedited development after the removal of all buds in the colony. Next, we characterized external morphology, ultrastructure, and abundance of circulatory blood cells in the vascular system of S. brakenhielmi. Macrophage-like cells (MLCs) are involved in zooid resorption and turnover. Proportions of MLCs in the blood of S. brakenhielmi corresponded to the peak of occurrence of this cell type during the budding cycle of B. schlosseri. We found several new blood cell types in S. brakenhielmi, including two cell types that resemble circulatory progenitor stem cells of other botryllid colonial ascidians. These cells showed features of undifferentiated cells and expressed mitotic marker Phospho-histone H3. Comparative studies of S. brakenhielmi and B. schlosseri

  20. Ecological observations on the colonial ascidian Didemnum sp. in a New England tide pool habitat

    USGS Publications Warehouse

    Valentine, P.C.; Carman, M.R.; Blackwood, D.S.; Heffron, E.J.

    2007-01-01

    The colonial ascidian Didemnum sp. has colonized northwestern Atlantic coastal habitats from southern Long Island, New York, to Eastport, Maine. It is also present in offshore habitats of the Georges Bank fishing grounds. It threatens to alter fisheries habitats and shellfish aquacultures. Observations in a tide pool at Sandwich, MA from December 2003 to February 2006 show that Didemnum sp. tolerates water temperatures ranging from ≤ 1 to > 24 °C, with daily changes of up to 11 °C. It attaches to pebbles, cobbles, and boulders, and it overgrows other tunicates, seaweeds, sponges, and bivalves. From May to mid July, colonies appear as small patches on the bottoms of rocks. Colonies grow rapidly from July to September, with some growth into December, and they range in color from pink to pale yellow to pale orange. Colony health declines from October through April, presumably in response to changes in water temperatures, and this degenerative process is manifested by color changes, by the appearance of small dark brown spots that represent clumps of fecal pellets in the colony, by scavenging by periwinkles, and by a peeling-away of colonies from the sides of cobbles and boulders. At Sandwich, colonies died that were exposed to air at low tide. The species does not exhibit this seasonal cycle of growth and decline in subtidal habitats (40–65 m) on the Georges Bank fishing grounds where the daily climate is relatively stable and annual water temperatures range from 4 to 15 °C. Experiments in the tide pool with small colony fragments (5 to 9 cm2) show they re-attach and grow rapidly by asexual budding, increasing in size 6- to 11-fold in the first 15 days. Didemnum sp. at Sandwich has no known predators except for common periwinkles (Littorina littorea) that graze on degenerating colonies in the October to April time period and whenever colonies are stressed by desiccation. The tendencies of the ascidian (1) to attach to firm substrates, (2) to rapidly overgrow

  1. Activation of a tunicate (Ciona intestinalis) xenobiotic receptor orthologue by both natural toxins and synthetic toxicants.

    PubMed

    Fidler, Andrew E; Holland, Patrick T; Reschly, Erica J; Ekins, Sean; Krasowski, Matthew D

    2012-02-01

    Vertebrate xenobiotic receptors are ligand-activated nuclear receptors (NRs) that bind exogenous biologically active chemicals before activating the transcription of genes involved in xenobiotic metabolism and excretion. Typically, xenobiotic receptors have ligand binding domains (LBDs) that can accommodate a structurally diverse array of molecules and in addition display high levels of inter-taxa sequence diversity suggestive of positive selection. Pursuing the idea that xenobiotic receptors may adaptively evolve to bind toxic chemicals commonly present in an organism's environment/diet, we examined ligand binding by a xenobiotic receptor orthologue of a marine filter-feeding organism. The solitary tunicate Ciona intestinalis (Phylum Chordata) genome encodes an orthologue of the vertebrate pregnane X receptor (PXR) and vitamin D receptor (VDR), here denoted CiVDR/PXRα. In a luciferase reporter assay the CiVDR/PXRα was activated, at nanomolar concentrations, by two of four natural marine microalgal biotoxins tested (okadaic acid, EC50 = 18.2 ± 0.9 nM and pectenotoxin-2, EC50 = 37.0 ± 3.5 nM) along with 1 of 11 synthetic toxicants (esfenvalerate: EC50 = 0.59 ± 0.7 μM). Two related C. intestinalis NRs, orthologous to vertebrate farnesoid X receptor and liver X receptors, respectively, along with the PXR of a freshwater fish (zebrafish, Danio rerio), were not activated by any of the 15 chemicals tested. In contrast, human PXR was activated by okadaic acid at similar concentrations to CiVDR/PXRα (EC50 = 7.2 ± 1.1 nM) but not by pectenotoxin-2. A common features pharmacophore developed for the CiVDR/PXRα ligand consisted of an off-center hydrogen bond acceptor flanked by two hydrophobic regions. The results of this study are consistent with the original hypothesis that natural toxins, present in the diet of filter-feeding marine invertebrates, may have acted as selective agents in the molecular evolution of tunicate xenobiotic receptors. Bioassays based on

  2. Fertilization in an egg-brooding colonial ascidian does not vary with population density.

    PubMed

    Phillippi, Aimee; Hamann, Ellen; Yund, Philip O

    2004-06-01

    The possibility that free-spawning marine organisms may be subject to fertilization failure at low population density (due to the effects of sperm dilution) has sparked much interest, but these effects have been demonstrated only in a few species that broadcast their eggs. Some egg-brooding species may overcome dilution effects by filtering low concentrations of sperm from seawater and fertilizing eggs throughout an extended period of time. We examined the effects of population density and size on fertilization in Botryllus schlosseri, a hermaphroditic colonial ascidian that free-spawns sperm, but broods eggs. We experimentally manipulated the size and density of mating groups and surveyed fertilization levels in natural populations that varied in density. Fertilization was not affected by variation in population size or density in either the experimental or natural populations. Near the end of the reproductive season, some eggs may have been fertilized too late to complete development, suggesting a temporal form of sperm limitation that has not been considered in other systems. We also detected greater variability in fertilization levels at lower population density. Nevertheless, these results suggest that caution must be used in extrapolating reported density effects on fertilization to all taxa of free-spawners; density effects may be reduced in brooders that have efficient sperm collection mechanisms.

  3. Complete DNA sequence of the mitochondrial genome of the ascidian Halocynthia roretzi (Chordata, Urochordata).

    PubMed Central

    Yokobori, S i; Ueda, T; Feldmaier-Fuchs, G; Pääbo, S; Ueshima, R; Kondow, A; Nishikawa, K; Watanabe, K

    1999-01-01

    The complete nucleotide sequence of the 14,771-bp-long mitochondrial (mt) DNA of a urochordate (Chordata)-the ascidian Halocynthia roretzi-was determined. All the Halocynthia mt-genes were found to be located on a single strand, which is rich in T and G rather than in A and C. Like nematode and Mytilus edulis mtDNAs, that of Halocynthia encodes no ATP synthetase subunit 8 gene. However, it does encode an additional tRNA gene for glycine (anticodon TCT) that enables Halocynthia mitochondria to use AGA and AGG codons for glycine. The mtDNA carries an unusual tRNA(Met) gene with a TAT anticodon instead of the usual tRNA(Met)(CAT) gene. As in other metazoan mtDNAs, there is not any long noncoding region. The gene order of Halocynthia mtDNA is completely different from that of vertebrate mtDNAs except for tRNA(His)-tRNA(Ser)(GCU), suggesting that evolutionary change in the mt-gene structure is much accelerated in the urochordate line compared with that in vertebrates. The amino acid sequences of Halocynthia mt-proteins deduced from their gene sequences are quite different from those in other metazoans, indicating that the substitution rate in Halocynthia mt-protein genes is also accelerated. PMID:10581290

  4. Complete DNA sequence of the mitochondrial genome of the ascidian Halocynthia roretzi (Chordata, Urochordata).

    PubMed

    Yokobori, S i; Ueda, T; Feldmaier-Fuchs, G; Pääbo, S; Ueshima, R; Kondow, A; Nishikawa, K; Watanabe, K

    1999-12-01

    The complete nucleotide sequence of the 14,771-bp-long mitochondrial (mt) DNA of a urochordate (Chordata)-the ascidian Halocynthia roretzi-was determined. All the Halocynthia mt-genes were found to be located on a single strand, which is rich in T and G rather than in A and C. Like nematode and Mytilus edulis mtDNAs, that of Halocynthia encodes no ATP synthetase subunit 8 gene. However, it does encode an additional tRNA gene for glycine (anticodon TCT) that enables Halocynthia mitochondria to use AGA and AGG codons for glycine. The mtDNA carries an unusual tRNA(Met) gene with a TAT anticodon instead of the usual tRNA(Met)(CAT) gene. As in other metazoan mtDNAs, there is not any long noncoding region. The gene order of Halocynthia mtDNA is completely different from that of vertebrate mtDNAs except for tRNA(His)-tRNA(Ser)(GCU), suggesting that evolutionary change in the mt-gene structure is much accelerated in the urochordate line compared with that in vertebrates. The amino acid sequences of Halocynthia mt-proteins deduced from their gene sequences are quite different from those in other metazoans, indicating that the substitution rate in Halocynthia mt-protein genes is also accelerated.

  5. Global Phylogeography of the Widely Introduced North West Pacific Ascidian Styela clava

    PubMed Central

    Goldstien, Sharyn J.; Dupont, Lise; Viard, Frédérique; Hallas, Paul J.; Nishikawa, Teruaki; Schiel, David R.; Gemmell, Neil J.; Bishop, John D. D.

    2011-01-01

    The solitary ascidian Styela clava Herdman, 1882 is considered to be native to Japan, Korea, northern China and the Russian Federation in the NW Pacific, but it has spread globally over the last 80 years and is now established as an introduced species on the east and west coasts of North America, Europe, Australia and New Zealand. In eastern Canada it reaches sufficient density to be a serious pest to aquaculture concerns. We sequenced a fragment of the cytochrome oxidase subunit I mitochondrial gene (COI) from a total of 554 individuals to examine the genetic relationships of 20 S. clava populations sampled throughout the introduced and native ranges, in order to investigate invasive population characteristics. The data presented here show a moderate level of genetic diversity throughout the northern hemisphere. The southern hemisphere (particularly New Zealand) displays a greater amount of haplotype and nucleotide diversity in comparison. This species, like many other invasive species, shows a range of genetic diversities among introduced populations independent of the age of incursion. The successful establishment of this species appears to be associated with multiple incursions in many locations, while other locations appear to have experienced rapid expansion from a potentially small population with reduced genetic diversity. These contrasting patterns create difficulties when attempting to manage and mitigate a species that continues to spread among ports and marinas around the world. PMID:21364988

  6. Immunotoxicity in ascidians: antifouling compounds alternative to organotins-IV. The case of zinc pyrithione.

    PubMed

    Cima, Francesca; Ballarin, Loriano

    2015-03-01

    New biocides such as the organometallic compound zinc pyrithione (ZnP) have been massively introduced by many countries in formulations of antifouling paints following the ban on tributyltin (TBT). The effects of sublethal concentrations (LC50=82.5 μM, i.e., 26.2 mg/l) on cultured haemocytes of the ascidian Botryllus schlosseri have been investigated and compared with TBT. The percentage of haemocytes with amoeboid morphology and containing phagocytised yeast cells were significantly (p<0.05) reduced after exposure to 0.1 (31.7 μg/l) and 0.5 μM (158 μg/l), respectively. An antagonistic interaction in inducing cytoskeletal alterations was observed when ZnP and TBT were co-present in the exposure medium. ZnP affected only the actin component. As caused by TBT, ZnP induced apoptosis and inhibited both oxidative phosphorylation and lysosomal activities. In contrast to the case of TBT, a decrement in Ca(2+)-ATPase activity and a decrease in cytosolic Ca(2+) were detected after incubation at the highest concentration (1 μM, i.e., 317.7 μg/l) used. In comparison with other antifouling compounds, ZnP shows as much toxicity as TBT to cultured haemocytes at extremely low concentrations interfering with fundamental cell activities.

  7. Multilocus genetic analyses differentiate between widespread and spatially restricted cryptic species in a model ascidian.

    PubMed

    Bock, Dan G; MacIsaac, Hugh J; Cristescu, Melania E

    2012-06-22

    Elucidating the factors that shape species distributions has long been a fundamental goal in ecology and evolutionary biology. In spite of significant theoretical advancements, empirical studies of range limits have lagged behind. Specifically, little is known about how the attributes that allow species to expand their ranges and become widespread vary across phylogenies. Here, we studied the ascidian Botryllus schlosseri, a worldwide invasive species that is also characterized by marked genetic subdivision. Our study includes phylogenetic and population genetic data based on mitochondrial and nuclear genes, as well as polymorphic microsatellites for B. schlosseri colonies sampled from the southern and northern coasts of Europe and the eastern and western coasts of North America. We demonstrate that this well-known model organism comprises three highly divergent and probably reproductively isolated cryptic species (A, D and E), with two more (B and C) being suggested by data retrieved from GenBank. Among these, species A, recovered in all of the surveyed regions, is by far the most common and widespread. By contrast, species B-E, occurring mostly in sites from northern Europe, are considerably more geographically restricted. These findings, along with inferences made on transport opportunity, suggest that divergent evolutionary histories promoted differences in invasive potential between B. schlosseri sibling species, indicating that attributes that facilitate dramatic shifts in range limits can evolve more easily and frequently than previously thought. We propose environmental disturbance as a selective force that could have shaped the evolution of invasiveness in the B. schlosseri complex.

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

    PubMed Central

    Leigh, Brittany; Karrer, Charlotte; Cannon, John P.; Breitbart, Mya; Dishaw, Larry J.

    2017-01-01

    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. PMID:28327522

  9. Mechanisms of helical swimming: asymmetries in the morphology, movement and mechanics of larvae of the ascidian Distaplia occidentalis.

    PubMed

    McHenry, M J

    2001-09-01

    A great diversity of unicellular and invertebrate organisms swim along a helical path, but it is not well understood how asymmetries in the body shape or the movement of propulsive structures affect a swimmer's ability to perform the body rotation necessary to move helically. The present study found no significant asymmetries in the body shape of ascidian larvae (Distaplia occidentalis) that could operate to rotate the body during swimming. By recording the three-dimensional movement of free-swimming larvae, it was found that the tail possessed two bends, each with constant curvature along their length. As these bends traveled posteriorly, the amplitude of curvature changes was significantly greater in the concave-left direction than in the concave-right direction. In addition to this asymmetry, the tail oscillated at an oblique angle to the midline of the trunk. These asymmetries generated a yawing moment that rotated the body in the counterclockwise direction from a dorsal view, according to calculations from hydrodynamic theory. The tails of resting larvae were bent in the concave-left direction with a curvature statistically indistinguishable from the median value for tail curvature during swimming. The flexural stiffness of the tails of larvae, measured in three-point bending, may be great enough to allow the resting curvature of the tail to have an effect on the symmetry of kinematics. This work suggests that asymmetrical tail motion is an important mechanism for generating a yawing moment during swimming in ascidian larvae and that these asymmetries may be caused by the tail's bent shape. Since helical motion requires that moments also be generated in the pitching or rolling directions, other mechanisms are required to explain fully how ascidian larvae generate and control helical swimming.

  10. The candidate Fu/HC gene in Botryllusschlosseri (Urochordata) and ascidians' historecognition--an oxymoron?

    PubMed

    Rinkevich, Buki; Douek, Jacob; Rabinowitz, Claudette; Paz, Guy

    2012-04-01

    Allorecognition, distinguishing self from non-self allogeneic tissues is the underlying basis of innate immunity. In the colonial tunicate Botryllus schlosseri this historecognition is governed at a single genetic locus, Fu/HC (for fusibility/histocompatibility), with hundreds of co-dominantly expressed alleles. Several years ago, De Tomaso et al. (2005) have revolutionized the discipline of invertebrate allorecognition by describing a novel form of immune recognition in B. schlosseri, a non-vertebrate candidate histocompatibility gene (cFu/HC), revealing that allorecognition machinery in urochordates has nothing in common with the vertebrates' MHC-based histocompatibility. The authors reported absolute concordance of fusibility and cFu/HC genotype, predicted fusion/rejection outcomes in allorecognition settings from allelic polymorphism at the cFu/HC, also claiming cFu/HC gene expressions only in tissues directly engaged in histocompatibility. Here, we raise queries for the validity of the results and conclusions of De Tomaso et al. (2005) publication. Our reservations include discrepancies in the paper's results, including the perplexing absence of key sequencing material from public domains and above all, our own impugning outcomes. These include cloning efforts, in situ hybridization results, semi quantitative PCR outcomes, and the incongruence emerged between fusion/rejection profiles and cFu/HC segregated polymorphism that separately and cumulatively contradict the original publication. We conclude that Botryllus histocompatibility properties are not signaled in the claimed cFu/HC and that cFu/HC gene is unlikely the allodeterminant for Botryllus histocompatibility locus. Hence, the molecular nature of the Fu/HC locus in botryllid ascidians is still awaiting elucidation.

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

    NASA Astrophysics Data System (ADS)

    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

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

    PubMed

    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.

  13. The invariant cleavage pattern displayed by ascidian embryos depends on spindle positioning along the cell's longest axis in the apical plane and relies on asynchronous cell divisions

    PubMed Central

    Dumollard, Rémi; Minc, Nicolas; Salez, Gregory; Aicha, Sameh Ben; Bekkouche, Faisal; Hebras, Céline; Besnardeau, Lydia; McDougall, Alex

    2017-01-01

    The ascidian embryo is an ideal system to investigate how cell position is determined during embryogenesis. Using 3D timelapse imaging and computational methods we analyzed the planar cell divisions in ascidian early embryos and found that spindles in every cell tend to align at metaphase in the long length of the apical surface except in cells undergoing unequal cleavage. Furthermore, the invariant and conserved cleavage pattern of ascidian embryos was found to consist in alternate planar cell divisions between ectoderm and endomesoderm. In order to test the importance of alternate cell divisions we manipulated zygotic transcription induced by β-catenin or downregulated wee1 activity, both of which abolish this cell cycle asynchrony. Crucially, abolishing cell cycle asynchrony consistently disrupted the spindle orienting mechanism underpinning the invariant cleavage pattern. Our results demonstrate how an evolutionary conserved cell cycle asynchrony maintains the invariant cleavage pattern driving morphogenesis of the ascidian blastula. DOI: http://dx.doi.org/10.7554/eLife.19290.001 PMID:28121291

  14. Trypsin-like enzyme from eggs of the ascidian (protochordate), Halocynthia roretzi. Purification, properties, and physiological role.

    PubMed

    Sawada, H; Kawahigashi, M; Yokosawa, H; Ishii, S

    1985-12-15

    A trypsin-like enzyme has been purified to apparent homogeneity from eggs of the ascidian, Halocynthia roretzi, by a procedure including column chromatography on diethylaminoethyl-cellulose, phenyl-Sepharose, and soybean trypsin inhibitor-immobilized Sepharose 4B. The molecular weight of the enzyme was estimated to be 31,000 and 33,000 by gel electrophoresis in sodium dodecyl sulfate under the reducing and the nonreducing conditions, respectively. The isoelectric point of the enzyme was 4.8. The pH optimum of the activity was 8.4. The enzyme was stable between pH 6 and 9 in the presence of 0.005% Brij 35 as a stabilizer. Substrate specificity of the purified enzyme was broad toward various peptidyl-arginine (or -lysine) 4-methylcoumaryl-7-amides and was similar to that of a trypsin-like enzyme found in the fertilization product. The purified enzyme was inhibited by diisopropyl fluorophosphate and a variety of trypsin inhibitors including leupeptin, but not, or scarcely, inhibited by p-chloromercuribenzoic acid, pepstatin, chymostatin, bestatin, elastatinal, and tosyl-phenylalanyl-chloromethane. The rankings in the potencies of leupeptin and its six analogs as the inhibitors of the purified enzyme were well correlated with those found in their inhibitory effects on the expansion of perivitelline space. Thus, the trypsin-like enzyme possibly present in the fertilization product participates in the expansion of perivitelline space of the egg during fertilization of the ascidian.

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

    PubMed Central

    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

  16. Transmission of cyanobacterial symbionts during embryogenesis in the coral reef ascidians Trididemnum nubilum and T. clinides (Didemnidae, Ascidiacea, Chordata).

    PubMed

    Kojima, Aoi; Hirose, Euichi

    2012-02-01

    Vertical transmission of cyanobacterial symbionts occurs in didemnid ascidians harboring Prochloron as an obligate symbiont; the photosymbionts are transferred from the parental ascidian colony to the offspring in various ways depending on host species. Although several didemnids harbor non-Prochloron cyanobacteria in their tunics, few studies have reported the processes of vertical transmission in these didemnids. Here we describe the histological processes of the transmission of cyanobacteria in two didemnids, Trididemnum nubilum harboring Synechocystis and T. clinides harboring three cyanobacterial species. In both species, the photosymbionts in the tunic of the parent colony were apparently captured by the tunic cells of the host and transferred to the embryos brooded in the tunic. The symbiont cells were then incorporated into the inner tunic of the embryo. This mode of transmission is essentially the same as that of T. miniatum harboring Prochloron in the tunic, although there are some differences among species in the timing of the release of the symbionts from the tunic cells. We suggest that the similar modes of vertical transmission are an example of convergent evolution caused by constraints in the distribution patterns of symbiont cells in the host colony.

  17. Morphological characterization of the tunic in the edible ascidian, Halocynthia roretzi (Drasche), with remarks on 'soft tunic syndrome' in aquaculture.

    PubMed

    Hirose, E; Ohtake, S-I; Azumi, K

    2009-05-01

    'Soft tunic syndrome' is a serious problem in the aquaculture of the edible ascidian, Halocynthia roretzi (Drasche), and often leads to mass mortality. Here, we describe the tunic morphology of intact and diseased ascidians to reveal structural differences between them. Morphologically, diseased tunics are not very different from intact tunics, although the former are thinner and softer than the latter. While several types of cells are distributed in the tunic, the cell types and their cytomorphologies were almost identical in both groups. As bacterial/protozoan cells were not found in either intact or diseased tunics, they are not the direct cause of soft tunic syndrome. The most remarkable difference was in the bundles of tunic fibres that compose the tunic matrix; in intact tunics, the thick bundles interlace to form a firm matrix, whereas in soft tunics, the tunic fibres do not form thick bundles. Furthermore, areas of low fibre density were found in diseased tunics. Therefore, soft tunic syndrome probably causes inhibition of bundle formation and degradation of tunic bundles, creating areas of low fibre density, although the causes remain unknown.

  18. Isolation of cDNA clones for mRNAs transcribed zygotically during cleavage in the ascidian, Halocynthia roretzi.

    PubMed

    Miya, Takahito; Nishida, Hiroki

    2002-02-01

    The ascidian larva consists of a relatively small number of different cell types, and the cell lineages during embryogenesis have been well described. The clonal restriction of developmental fate takes place considerably early in development. The fates of most of the blastomeres become tissue-restricted by the 110-cell stage, just before the onset of gastrulation. To elucidate the molecular basis of the early events of fate determination in the ascidian Halocynthia roretzi, we isolated the genes for which zygotic expression is initiated during the early cleavage stages. Here we report 18 genes isolated by subtractive hybridization screening between 110-cell embryos and fertilized eggs. The expression of most (13) of the genes was initiated at the 32-cell stage. The genes were subdivided into three groups according to their spatial expression patterns. The first group included clones expressed throughout almost the entire embryo. The second and third groups represented clones expressed mainly in the animal hemisphere and in a subset of vegetal blastomeres, respectively. One of the genes, HrHesl1, encoded a polypeptide containing the bHLH domain that is similar to those of the Hairy/Enhancer of split/Deadpan family of transcriptional repressors. HrHesl1 was expressed exclusively in epidermal precursor cells during cleavage. Another gene named HrWnt-5 beta was expressed in muscle precursors.

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

    PubMed

    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.

  20. Neural differentiation in cleavage-arrested ascidian blastomeres induced by a proteolytic enzyme.

    PubMed Central

    Okado, H; Takahashi, K

    1993-01-01

    1. As previously reported, ectodermal a4-2 blastomeres isolated from 8-cell embryos of the ascidian, Halocynthia roretzi or aurantium, and cultured under conditions of cleavage arrest always differentiated into an epidermal phenotype, showing long-lasting Ca(2+)-dependent action potentials and/or tunic on the cell surface. a4-2 blastomeres contacted by a chordamesodermal blastomere, A4-1, differentiated into a neural phenotype, characterized by fast Na(+)-dependent spikes. Differentiation to a similar neural phenotype occurred when isolated a4-2 blastomeres from H. aurantium embryos were treated with > 0.003% subtilisin for 60 min at the 32-cell stage of the control embryo. Comparisons between induction by cell contact and induction by proteolytic enzymes were made and showed them to be similar in several respects. 2. When the serine protease, subtilisin, was used as the neural inducer, neural competence of a4-2 blastomeres, measured as the percentage frequency of the induction of Na+ spikes, increased after the 32-cell stage and decreased during the gastrula stage. The time course of the neural competence was the same as that for contact with the A4-1 blastomere. 3. The neural competence of four different ectodermal blastomeres isolated from the 16-cell embryo was also examined using subtilisin as a neural inducer, and by contact with the A4-1 blastomere from the 8-cell embryo. The competence was higher in anterior blastomeres than in posterior blastomeres for both types of induction. This regional difference in neural competence along the antero-posterior axis paralleled that expected from neural cell lineage during normal development, i.e. blastomeres with more cells of neural lineage among their derivatives showed higher competence. 4. Streptomyces subtilisin inhibitor, SSI (0.1%), a specific protease inhibitor for subtilisin-type serine proteases, significantly suppressed (50%) neural induction of the ectodermal blastomere, a4-2, by contact with the

  1. Biogeography of Mediterranean Invasions

    NASA Astrophysics Data System (ADS)

    Groves, R. H.; di Castri, F.

    The Mediterranean basin, California, Chile, the western Cape of South Africa, and southern Australia share a Mediterranean climate characterized by cool, wet winters and hot, dry summers. These five regions have differing patterns of human settlement, but similarities in natural vegetation and some faunal assemblages. These likenesses are enhanced with time by an increasing level of biotic exchange among the regions. An initiative of a subcommittee of SCOPE (Scientific Committee on Problems of the Environment), which realized that the integrity of many natural ecosystems is being threatened by the ingress of invasive species, this book uniquely documents the introduced floras and faunas, especially plants, buds, and mammals, in these five regions of Mediterranean climate, and aims to increase our understanding of the ecology of biological invasions. In doing so, it points a way to more effectively manage the biota of these regions.

  2. Toxic effects of two pesticides, Imazalil and Triadimefon, on the early development of the ascidian Phallusia mammillata (Chordata, Ascidiacea).

    PubMed

    Pennati, Roberta; Groppelli, Silvia; Zega, Giuliana; Biggiogero, Maira; De Bernardi, Fiorenza; Sotgia, Cristina

    2006-09-12

    Azole compounds are fungicides used in agriculture and in clinical area and are suspected to produce craniofacial malformations in vertebrates. Toxicity tests on sperm viability, fertilization and embryogenesis of the solitary ascidian Phallusia mammillata were performed to evaluate the effects of two azole derivatives, Imazalil and Triadimefon. Ascidian (Chordata, Ascidiacea) embryos and larvae could provide biological criteria for seawater quality standards because the larvae are lecitotrophic and have a short pelagic period, allowing to run the larval toxicity tests over a short period of time. Imazalil and Triadimefon proved to have strong consequences on P. mammillata. They could influence the reproductive rate of the animal exerting their effects at different levels: acting as spermiotoxic agents, inhibiting fertilization and impairing embryological development. Fertilization rate significantly decreased after 30min exposure of sperm to 25microM Imazalil (P<0.0001) and after exposure of both gametes to 50microM Imazalil (P<0.05) and 1mM Triadimefon (P<0.0001) as compared to controls. Malformations caused by exposure of embryos to both substances were dose dependent. Imazalil median teratogenic concentration (TC50 concentration, the concentration that resulted in 50% malformed larvae) value was 0.67microM and median lethal concentration (LC50, the concentration that resulted in 50% embryos dead before completing the development) value was 10.23microM while for Triadimefon TC50 value was 29.56 and LC50 value was 173.7microM. Larvae developed from embryos treated with Imazalil and Triadimefon showed alterations of the anterior structures of the trunk: papillary nerves and the anterior central nervous system failed to correctly differentiate, as showed by immunostaining with anti-beta-tubulin antibody. Comparing the anomalies caused by retinoic acid, reported in a previous study, it was possible to hypothesize that malformations induced by Imazalil and

  3. LPS challenge regulates gene expression and tissue localization of a Ciona intestinalis gene through an alternative polyadenylation mechanism.

    PubMed

    Vizzini, Aiti; Bonura, Angela; Parrinello, Daniela; Sanfratello, Maria Antonietta; Longo, Valeria; Colombo, Paolo

    2013-01-01

    A subtractive hybridization strategy for the identification of differentially expressed genes was performed between LPS-challenged and naive Ciona intestinalis. This strategy allowed the characterization of two transcripts (Ci8short and Ci8long) generated by the use of two Alternative Polyadenylation sites. The Ci8long transcript contains a protein domain with relevant homology to several components of the Receptor Transporting Protein (RTP) family not present in the Ci8short mRNA. By means of Real Time PCR and Northern Blot, the Ci8short and Ci8long transcripts showed a different pattern of gene expression with the Ci8short mRNA being strongly activated after LPS injection in the pharynx. In situ hybridization analysis demonstrated that the activation of the APA site also influenced the tissue localization of the Ci8short transcript. This analysis showed that the Ci8long mRNA was expressed in hemocytes meanwhile the Ci8short mRNA was highly transcribed also in vessel endothelial cells and in the epithelium of pharynx. These findings demonstrated that regulation of gene expression based on different polyadenylation sites is an ancestral powerful strategy influencing both the level of expression and tissue distribution of alternative transcripts.

  4. Aquaculture fouling: Efficacy of potassium monopersulphonate triple salt based disinfectant (Virkon® Aquatic) against Ciona intestinalis.

    PubMed

    Paetzold, S Christine; Davidson, Jeff

    2011-07-01

    With the increasing spread of invasive marine species and their detrimental effects on aquaculture operations globally, mitigation strategies need to be optimized to mitigate economic impacts. The efficacy of a potassium monopersulphonate triple salt based disinfectant used in the aquaculture industry (Virkon® Aquatic at 0.5-5%) was evaluated against the solitary tunicate Ciona intestinalis, as well as the susceptibility of three different age groups of C. intestinalis to the treatment and the effect of the disinfectant on mussel mortality. Younger C. intestinalis were most affected by all treatments, and almost all immersion applications significantly decreased the biomass of C. intestinalis compared to untreated plates. Disinfectant solutions of ≥ 1% reduced biomass below pre-treatment levels. Mussel mortality was low, especially for solutions <3%. C. intestinalis should be treated 4 weeks post-settlement to maximize antifouling treatment effects. Immersion in 3% disinfectant for 30 s reduced the biomass of C. intestinalis by up to 89% and would be feasible in field applications using existing treatment equipment.

  5. A new genus of Asterocheridae (Copepoda: Siphonostomatoida) ectoassociate of the ascidian Eudistoma vannamei Millar, 1977 (Polycitoridae) from Brazil.

    PubMed

    Johnsson, Rodrigo; Bahia, Cristiano; Neves, Elizabeth

    2016-05-23

    Asterocheres Boeck, 1860 is the largest genus of the siphonostomatoid copepod family Asterocheridae, containing 63 valid species. The genus is known for its symbiotic relationships with many marine invertebrate taxa, especially sponges, cnidarians, bryozoans, and echinoderms. Recent studies have restricted the diagnosis of this genus. Consequently, many species are now considered as species inquirendae. The present paper describes a new species living externally on the tunic of Eudistoma vannamei Millar, 1977, an endemic ascidian from Brazil. As the new species does not fit Asterocheres in the strict sense, a new genus is erected to accommodate it. Setacheres gen. nov. is characterized by its possession of two distal setae on the third endopodal segment of P3, thus differing from the distal seta and spine pattern that is deemed as diagnostic of Asterocheres. A revision and comparison of Asterocheres´ species inquirendae revealed eight species sharing the same generic characteristics and were thus reallocated as members of the new genus.

  6. Interspecific hybridization between an anural and urodele ascidian: differential expression of urodele features suggests multiple mechanisms control anural development.

    PubMed

    Swalla, B J; Jeffery, W R

    1990-12-01

    Anural development in the ascidian Molgula occulta was examined using tissue-specific markers and interspecific hybridization. Unlike most ascidians, which develop into a swimming tadpole larva (urodele development), M. occulta eggs develop into a tailless slug-like larva (anural development) which metamorphoses into an adult. M. occulta embryos show conventional early cleavage patterns, gastrulation, and neurulation, but then diverge from the urodele developmental mode during larval morphogenesis. M. occulta larvae do not contain a pigmented sensory cell in their brain or form a tail with differentiated notochord and muscle cells. As shown by in situ hybridization with cloned probes and analysis of in vitro translation products, M. occulta embryos do not accumulate high levels of alpha actin or myosin heavy chain mRNA. In contrast, acetylcholinesterase is expressed in muscle lineage cells, indicating that various muscle cell features are differentially suppressed. M. occulta embryos also lack tyrosinase activity, suggesting that suppression of brain pigment cell differentiation occurs at an early step in development. M. occulta eggs fertilized with sperm from Molgula oculata (a closely related urodele species) develop into hybrid larvae exhibiting some of the missing urodele features. Some hybrid embryos develop tyrosinase activity and differentiate a brain pigment cell and a short row of notochord cells, and form a short tail. These urodele features appeared together or separately in different hybrid embryos suggesting that they develop by independent mechanisms. In contrast, alpha actin and myosin heavy chain mRNA accumulation was not enhanced in hybrid embryos. These results suggest that multiple mechanisms control anural development.

  7. Anticancer effects of brominated indole alkaloid Eudistomin H from marine ascidian Eudistoma viride against cervical cancer cells (HeLa).

    PubMed

    Rajesh, Rajaian Pushpabai; Annappan, Murugan

    2015-01-01

    Marine invertebrates called ascidians are prolific producers of bioactive substances. The ascidian Eudistoma viride, distributed along the Southeast coast of India, was investigated for its in vitro cytotoxic activity against human cervical carcinoma (HeLa) cells by the MTT assay. The crude methanolic extract of E. viride, with an IC50 of 53 μg/ml, was dose-dependently cytotoxic. It was more potent at 100 μg/ml than cyclohexamide (1 μg/ml), reducing cell viability to 9.2%. Among nine fractions separated by chromatography, ECF-8 exhibited prominent cytoxic activity at 10 μg/ml. The HPLC fraction EHF-21 of ECF-8 was remarkably dose- and time-dependently cytotoxic, with 39.8% viable cells at 1 μg/ml compared to 51% in cyclohexamide-treated cells at the same concentration; the IC50 was 0.49 μg/ml. Hoechst staining of HeLa cells treated with EHF-21 at 0.5 μg/ml revealed apoptotic events such an cell shrinkage, membrane blebbing, chromatin condensation and formation of apoptotic bodies. Cell size and granularity study showed changes in light scatter, indicating the characteristic feature of cells dying by apoptosis. The cell-cycle analysis of HeLa cells treated with fraction EHF-21 at 1 μg/ml showed the marked arrest of cells in G0/G1, S and G2/M phases and an increase in the sub G0/G1 population indicated an increase in the apoptotic cell population. The statistical analysis of the sub-G1 region showed a dose-dependent induction of apoptosis. DNA fragmentation was also observed in HeLa cells treated with EHF-21. The active EHF-21 fraction, a brominated indole alkaloid Eudistomin H, led to apoptotic death of HeLa cells.

  8. Southeastern Mediterranean Panorama

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This oblique northwestward looking panorama view shows the southeastern Mediterranean (29.0N, 33.0E) in great detail. The Sinai Peninsula, the eastern Arabian Desert, the Nile River Valley and Delta as well as the Qatara Depression in Egypt are all prominently portrayed. Even Mt. Sinai is visible in the lower left center of the view. The dusty atmosphere of the region can be seen as a general haziness in the atmosphere.

  9. The Mediterranean salinity crisis

    SciTech Connect

    Hsue, K.J.

    1988-08-01

    That the Mediterranean Sea underwent a salinity crisis during the Miocene (Messinian) is proven by the 1970 JOIDES deep sea drilling expedition. Subsequent work by ocean drilling and by studies on land have recorded the history of this crisis. Based upon the deep desiccated-basin model, the use of event-stratigraphy, calibrated by strontium-isotope dating and magnetostratigraphy, has enabled them to decipher the following events between 6.0 and 5.1 Ma: (1) deposition of marine diatom-rich sediments in a partially restricted basin, (2) first desiccation of the Mediterranean when Calcare di base was deposited at a time of isolation from the Atlantic because of a glacial eustatic drop of sea level, (3) influx of marine waters through southern Spanish basins to furnish brines for the deposition of the main salt, (4) Intra-Messinian desiccation, as evidenced by the erosional unconformity above the lower evaporite, (5) Intra-Messinian denudation, when reefs grew on Cyprus and marine sediments were deposited in basins, (6) frequency isolations due to oscillating sea level, when the upper evaporite was deposited, (7) Lago mare, formation of freshwater and brackish lakes due to influx of Paratethys water, (8) opening of the Gibraltar and Pliocene inundation of the Mediterranean.

  10. Localization and enzymatic activity profiles of the proteases responsible for tachykinin-directed oocyte growth in the protochordate, Ciona intestinalis.

    PubMed

    Aoyama, Masato; Kawada, Tsuyoshi; Satake, Honoo

    2012-03-01

    We previously substantiated that Ci-TK, a tachykinin of the protochordate, Ciona intestinalis (Ci), triggered oocyte growth from the vitellogenic stage (stage II) to the post-vitellogenic stage (stage III) via up-regulation of the gene expression and enzymatic activity of the proteases: cathepsin D, carboxypeptidase B1, and chymotrypsin. In the present study, we have elucidated the localization, gene expression and activation profile of these proteases. In situ hybridization showed that the Ci-cathepsin D mRNA was present exclusively in test cells of the stage II oocytes, whereas the Ci-carboxypeptidase B1 and Ci-chymotrypsin mRNAs were detected in follicular cells of the stage II and stage III oocytes. Double-immunostaining demonstrated that the immunoreactivity of Ci-cathepsin D was largely colocalized with that of the receptor of Ci-TK, Ci-TK-R, in test cells of the stage II oocytes. Ci-cathepsin D gene expression was detected at 2h after treatment with Ci-TK, and elevated for up to 5h, and then slightly decreased. Gene expression of Ci-carboxypeptidase B1 and Ci-chymotrypsin was observed at 5h after treatment with Ci-TK, and then decreased. The enzymatic activities of Ci-cathepsin D, Ci-carboxypeptidase B1, and Ci-chymotrypsin showed similar alterations with 1-h lags. These gene expression and protease activity profiles verified that Ci-cathepsin D is initially activated, which is followed by the activation of Ci-carboxypeptidase B1 and Ci-chymotrypsin. Collectively, the present data suggest that Ci-TK directly induces Ci-cahtepsin D in test cells expressing Ci-TK receptor, leading to the secondary activation of Ci-chymotrypsin and Ci-carboxypeptidase B1 in the follicle in the tachykininergic oocyte growth pathway.

  11. Fatty Acid and Lipid Profiles with Emphasis on n-3 Fatty Acids and Phospholipids from Ciona intestinalis.

    PubMed

    Zhao, Yadong; Wang, Miao; Lindström, Mikael E; Li, Jiebing

    2015-10-01

    In order to establish Ciona intestinalis as a new bioresource for n-3 fatty acids-rich marine lipids, the animal was fractionated into tunic and inner body tissues prior to lipid extraction. The lipids obtained were further classified into neutral lipids (NL), glycolipids (GL) and phospholipids (PL) followed by qualitative and quantitative analysis using GC-FID, GC-MS, (1)H NMR, 2D NMR, MALDI-TOF-MS and LC-ESI-MS methods. It was found that the tunic and inner body tissues contained 3.42-4.08% and 15.9-23.4% of lipids respectively. PL was the dominant lipid class (42-60%) irrespective of the anatomic fractions. From all lipid fractions and classes, the major fatty acids were 16:0, 18:1n-9, C20:1n-9, C20:5n-3 (EPA) and C22:6n-3 (DHA). The highest amounts of long chain n-3 fatty acids, mainly EPA and DHA, were located in PL from both body fractions. Cholestanol and cholesterol were the dominant sterols together with noticeable amounts of stellasterol, 22 (Z)-dehydrocholesterol and lathosterol. Several other identified and two yet unidentified sterols were observed for the first time from C. intestinalis. Different molecular species of phosphatidylcholine (34 species), sphingomyelin (2 species), phosphatidylethanolamine (2 species), phosphatidylserine (10 species), phosphatidylglycerol (9 species), ceramide (38 species) and lysophospholipid (5 species) were identified, representing the most systematic PL profiling knowledge so far for the animal. It could be concluded that C. intestinalis lipids should be a good alternative for fish oil with high contents of n-3 fatty acids. The lipids would be more bioavailable due to the presence of the fatty acids being mainly in the form of PL.

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

    PubMed

    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.

  13. SMED - Sulphur MEditerranean Dispersion

    NASA Astrophysics Data System (ADS)

    Salerno, Giuseppe G.; Sellitto, Pasquale; Corradini, Stefano; Di Sarra, Alcide Giorgio; Merucci, Luca; Caltabiano, Tommaso; La Spina, Alessandro

    2016-04-01

    Emissions of volcanic gases and particles can have profound impacts on terrestrial environment, atmospheric composition, climate forcing, and then on human health at various temporal and spatial scales. Volcanic emissions have been identified as one of the largest sources of uncertainty in our understanding of recent climate change trends. In particular, a primary role is acted by sulphur dioxide emission due to its conversion to volcanic sulphate aerosol via atmospheric oxidation. Aerosols may play a key role in the radiative budget and then in photochemistry and tropospheric composition. Mt. Etna is one of the most prodigious and persistent emitters of gasses and particles on Earth, accounting for about 10% of global average volcanic emission of CO2 and SO2. Its sulphur emissions stand for 0.7 × 106 t S/yr9 and then about 10 times bigger than anthropogenic sulphur emissions in the Mediterranean area. Centrepiece of the SMED project is to advance the understanding of volcanogenic sulphur dioxide and sulphate aerosol particles dispersion and radiative impact on the downwind Mediterranean region by an integrated approach between ground- and space-based observations and modelling. Research is addressed by exploring the potential relationship between proximal SO2 flux and aerosol measured remotely in the volcanic plume of Mt. Etna between 2000 and 2014 and distal aerosol ground-based measurements in Lampedusa, Greece, and Malta from AERONET network. Ground data are combined with satellite multispectral polar and geostationary imagers able to detect and retrieve volcanic ash and SO2. The high repetition time of SEVIRI (15 minutes) will ensure the potential opportunity to follow the entire evolution of the volcanic cloud, while, the higher spatial resolution of MODIS (1x1 km2), are exploited for investigating the probability to retrieve volcanic SO2 abundances from passive degassing. Ground and space observations are complemented with atmospheric Lagrangian model

  14. Expression of Ciona intestinalis variable region-containing chitin-binding proteins during development of the gastrointestinal tract and their role in host-microbe interactions.

    PubMed

    Liberti, Assunta; Melillo, Daniela; Zucchetti, Ivana; Natale, Lenina; Dishaw, Larry J; Litman, Gary W; De Santis, Rosaria; Pinto, Maria Rosaria

    2014-01-01

    Variable region-containing chitin-binding proteins (VCBPs) are secreted, immune-type molecules that have been described in both amphioxus, a cephalochordate, and sea squirt, Ciona intestinalis, a urochordate. In adult Ciona, VCBP-A, -B and -C are expressed in hemocytes and the cells of the gastrointestinal tract. VCBP-C binds bacteria in the stomach lumen and functions as an opsonin in vitro. In the present paper the expression of VCBPs has been characterized during development using in situ hybridization, immunohistochemical staining and quantitative polymerase chain reaction (qPCR) technologies. The expression of VCBP-A and -C is detected first in discrete areas of larva endoderm and becomes progressively localized during differentiation in the stomach and intestine, marking the development of gut tracts. In "small adults" (1-2 cm juveniles) expression of VCBP-C persists and VCBP-A gradually diminishes, ultimately replaced by expression of VCBP-B. The expression of VCBP-A and -C in stage 7-8 juveniles, at which point animals have already started feeding, is influenced significantly by challenge with either Gram-positive or -negative bacteria. A potential role for VCBPs in gut-microbiota interactions and homeostasis is indicated.

  15. The population genomics of a fast evolver: high levels of diversity, functional constraint, and molecular adaptation in the tunicate Ciona intestinalis.

    PubMed

    Tsagkogeorga, Georgia; Cahais, Vincent; Galtier, Nicolas

    2012-01-01

    Phylogenomics has revealed the existence of fast-evolving animal phyla in which the amino acid substitution rate, averaged across many proteins, is consistently higher than in other lineages. The reasons for such differences in proteome-wide evolutionary rates are still unknown, largely because only a handful of species offer within-species genomic data from which molecular evolutionary processes can be deduced. In this study, we use next-generation sequencing technologies and individual whole-transcriptome sequencing to gather extensive polymorphism sequence data sets from Ciona intestinalis. Ciona is probably the best-characterized member of the fast-evolving Urochordata group (tunicates), which was recently identified as the sister group of the slow-evolving vertebrates. We introduce and validate a maximum-likelihood framework for single-nucleotide polymorphism and genotype calling, based on high-throughput short-read typing. We report that the C. intestinalis proteome is characterized by a high level of within-species diversity, efficient purifying selection, and a substantial percentage of adaptive amino acid substitutions. We conclude that the increased rate of amino acid sequence evolution in tunicates, when compared with vertebrates, is the consequence of both a 2-6 times higher per-year mutation rate and prevalent adaptive evolution.

  16. Expression of Ciona intestinalis Variable Region-Containing Chitin-Binding Proteins during Development of the Gastrointestinal Tract and Their Role in Host-Microbe Interactions

    PubMed Central

    Liberti, Assunta; Melillo, Daniela; Zucchetti, Ivana; Natale, Lenina; Dishaw, Larry J.; Litman, Gary W.; De Santis, Rosaria; Pinto, Maria Rosaria

    2014-01-01

    Variable region-containing chitin-binding proteins (VCBPs) are secreted, immune-type molecules that have been described in both amphioxus, a cephalochordate, and sea squirt, Ciona intestinalis, a urochordate. In adult Ciona, VCBP-A, -B and -C are expressed in hemocytes and the cells of the gastrointestinal tract. VCBP-C binds bacteria in the stomach lumen and functions as an opsonin in vitro. In the present paper the expression of VCBPs has been characterized during development using in situ hybridization, immunohistochemical staining and quantitative polymerase chain reaction (qPCR) technologies. The expression of VCBP-A and -C is detected first in discrete areas of larva endoderm and becomes progressively localized during differentiation in the stomach and intestine, marking the development of gut tracts. In “small adults” (1–2 cm juveniles) expression of VCBP-C persists and VCBP-A gradually diminishes, ultimately replaced by expression of VCBP-B. The expression of VCBP-A and -C in stage 7–8 juveniles, at which point animals have already started feeding, is influenced significantly by challenge with either Gram-positive or -negative bacteria. A potential role for VCBPs in gut-microbiota interactions and homeostasis is indicated. PMID:24788831

  17. Reviving the Mediterranean Olive Community

    ERIC Educational Resources Information Center

    Zaferatos, Nicholas C.

    2011-01-01

    This article presents the findings of a collaborative investigation by six nongovernment organisations (NGOs) from five European-Mediterranean countries to identify a framework for reversing rural marginalisation in Mediterranean communities through sustainable forms of community-based agricultural development. The project brought together…

  18. [Massive mortality of marine invertebrates: an unprecedented event in northwestern Mediterranean].

    PubMed

    Perez, T; Garrabou, J; Sartoretto, S; Harmelin, J G; Francour, P; Vacelet, J

    2000-10-01

    An unprecedented mass mortality event has been observed at the end of the summer 1999 along the coasts of Provence (France) and Ligury (Italy). This event has severely affected a wide array of sessile filter-feeder invertebrates from hard-substratum communities, such as sponges (particularly the keratose sponges Hippospongia and Spongia), cnidarians (particularly the anthozoans Corallium, Paramuricea, Eunicella and Cladocora), bivalves, ascidians and bryozoans. Along the Provence coasts, the outbreak spread from east to west. Exceptionally high and constant temperatures of the whole water column (23-24 degrees C, for over one month, down to 40 m) could have determined an environmental context favourable to the mass mortality event. Like the thermal anomaly, the mortality is limited in depth. However, we cannot ascertain whether temperature had a direct effect on organisms or acted in synergy with a latent and/or waterborne agent (microbiological or chemical). Taking into account the global warming context in the NW-Mediterranean, monitoring programs of physical-chemical parameters and vulnerable populations should rapidly be set up.

  19. T-Type Ca2+ Current Activity during Oocyte Growth and Maturation in the Ascidian Styela plicata

    PubMed Central

    Gallo, Alessandra; Russo, Gian Luigi; Tosti, Elisabetta

    2013-01-01

    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. PMID:23349937

  20. Catecholamines are produced by ascidian immune cells: The involvement of PKA and PKC in the adrenergic signaling pathway.

    PubMed

    de Abreu Mello, Andressa; Fernandes de Souza, Jéssica; Nunes da Fonseca, Rodrigo; Allodi, Silvana; Monteiro de Barros, Cintia

    2017-03-01

    The stress response is a complex mechanism, which includes changes in the immune system to enable organisms to maintain homeostasis. The neurohormones dopamine, noradrenaline (NA) and adrenalin are responsible for the physiological modulations that occur during acute stress. In the present study, we analyzed the effects of NA on the immune system specific to nitric-oxide (NO) production by subpopulations of immune cells (hemocytes) of the ascidian Phallusia nigra. We also investigated the capability of immune cells to produce catecholamine (CA). Finally, we tested the involvement of protein kinase A (PKA) and C (PKC) in the NA downstream signaling pathway. The results revealed that NA can reduce NO production by P. nigra hemocytes threefold, and that signet-ring cells, univacuolar refractile granulocytes and morula cells are the cell types most involved in this event. A challenge effected with Zymosan A induced CA production, and co-incubation with both inhibitors of the second messengers PKA and PKC revealed the involvement of these molecules in the adrenergic pathway of P. nigra hemocytes. Taken together, these results suggest that NO production can be down-regulated by NA through α- and β-adrenoceptors via the second messengers PKA and PKC.

  1. Msxb is a core component of the genetic circuitry specifying the dorsal and ventral neurogenic midlines in the ascidian embryo.

    PubMed

    Roure, Agnès; Darras, Sébastien

    2016-01-01

    The tail ascidian larval peripheral nervous system is made up of epidermal sensory neurons distributed more or less regularly in ventral and dorsal midlines. Their formation occurs in two-steps: the ventral and dorsal midlines are induced as neurogenic territories by Fgf9/16/20 and Admp respectively. The Delta2/Notch interaction then controls the number of neurons that form. The genetic machinery acting between the inductive processes taking place before gastrulation and neuron specification at tailbud stages are largely unknown. The analysis of seven transcription factors expressed in the forming midlines revealed an unexpected complexity and dynamic of gene expression. Their systematic overexpression confirmed that these genes do not interact following a linear cascade of activation. However, the integration of our data revealed the distinct key roles of the two upstream factors Msxb and Nkx-C that are the earliest expressed genes and the only ones able to induce neurogenic midline and ESN formation. Our data suggest that Msxb would be the primary midline gene integrating inputs from the ventral and dorsal inducers and launching a pan-midline transcriptional program. Nkx-C would be involved in tail tip specification, in maintenance of the pan-midline network and in a posterior to anterior wave controlling differentiation.

  2. Larval adhesive organs and metamorphosis in ascidians. II. The mechanism of eversion of the papillae of Distaplia occidentalis.

    PubMed

    Cloney, R A

    1979-09-01

    The cup-shaped adhesive papillae of Distaplia occidentalis evert at the onset of metamorphosis and each transforms into a hyperboloidal configuration. The rate of transformation is a function of temperature. At 14 degrees C complete eversion takes about 30 seconds. Myoepithelial cells that extend from the rim to the base on the cup contract. Simultaneously the central part of the papilla advances 60--70 micrometers. During the last phases of eversion, collocytes (cells that secrete adhesives) on the inner wall of the cup and on the sides of the axial protrusion flow outward and form a collar-like structure. The myoepithelial cells contain arrays of thick and thin filaments. These become compacted during contraction. The surfaces of these cells become extensively folded as they shorten to about 1/3 of rest length. According to the proposed model the myoepithelial cells are the driving force in papillary eversion. Immediately after eversion is completed the papillae begin to retract. Eversion of the papillae is not inhibited by cytochalasin B, but the process of retraction is reversibly inhibited. Some histological characteristics of five types of everting papillae in four families of ascidians are compared.

  3. Lineage divergence, local adaptation across a biogeographic break, and artificial transport, shape the genetic structure in the ascidian Pyura chilensis.

    PubMed

    Segovia, Nicolás I; Gallardo-Escárate, Cristian; Poulin, Elie; Haye, Pilar A

    2017-03-16

    Marine benthic organisms inhabit a heterogeneous environment in which connectivity between populations occurs mainly through dispersive larval stages, while local selective pressures acting on early life history stages lead to non-random mortality, shaping adaptive genetic structure. In order to test the influence of local adaptation and neutral processes in a marine benthic species with low dispersal, in this study we used Genotyping by Sequencing technology to compare the neutral and putatively selected signals (neutral and outlier loci, respectively) in SNPs scattered throughout the genome in six local populations of the commercially exploited ascidian Pyura chilensis along the southeast Pacific coast (24°-42°S). This species is sessile as an adult, has a short-lived larval stage, and may also be dispersed by artificial transport as biofouling. We found that the main signal in neutral loci was a highly divergent lineage present at 39°S, and a subjacent signal that indicated a separation at 30°S (north/south), widely reported in the area. North/south separation was the main signal in outlier loci, and the linage divergence at 39°S was subjacent. We conclude that the geographic structure of the genetic diversity of outlier and neutral loci was established by different strengths of environmental, historical and anthropogenic factors.

  4. Photoadaptation and protection against active forms of oxygen in the symbiotic procaryote Prochloron sp. and its ascidian host

    SciTech Connect

    Lesser, M.P.; Stochaj, W.R. )

    1990-06-01

    Superoxide dismutase, ascorbate, peroxidase, and catalase activities were studied in the symbiotic photosynthetic procaryote Prochloron sp. and its ascidian host Lissoclinum patella. The protein-specific activities of these antioxidant enzymes in the Prochloron sp. and L. patella collected at different depths from the Great Barrier Reef, Australia, were directly proportional to irradiance, whereas the pigment concentrations in the Prochloron sp. were inversely proportional to irradiance. The presence of a cyanide-sensitive superoxide dismutase, presumably a Cu-An metalloprotein, in the Prochloron sp. extends the possible phylogenetic distribution of this protein. The concentration of UV-absorbing mycosporine-like amino acids in inversely proportional to irradiance in both the host and symbiont, suggesting that these compounds may not provide sufficient protection against UV radiation in high-irradiance environments. The significant differences in the specific activities of these antioxidant enzymes, cellular photosynthetic pigment concentrations, and UV-absorbing compounds from high- and low-irradiance habitats constitute an adaptive response to different photic environments. These photoadaptive responses are essential to prevent inhibition of photosynthesis by high fluxes of visible and UV radiation.

  5. Lineage divergence, local adaptation across a biogeographic break, and artificial transport, shape the genetic structure in the ascidian Pyura chilensis

    PubMed Central

    Segovia, Nicolás I.; Gallardo-Escárate, Cristian; Poulin, Elie; Haye, Pilar A.

    2017-01-01

    Marine benthic organisms inhabit a heterogeneous environment in which connectivity between populations occurs mainly through dispersive larval stages, while local selective pressures acting on early life history stages lead to non-random mortality, shaping adaptive genetic structure. In order to test the influence of local adaptation and neutral processes in a marine benthic species with low dispersal, in this study we used Genotyping by Sequencing technology to compare the neutral and putatively selected signals (neutral and outlier loci, respectively) in SNPs scattered throughout the genome in six local populations of the commercially exploited ascidian Pyura chilensis along the southeast Pacific coast (24°–42°S). This species is sessile as an adult, has a short-lived larval stage, and may also be dispersed by artificial transport as biofouling. We found that the main signal in neutral loci was a highly divergent lineage present at 39°S, and a subjacent signal that indicated a separation at 30°S (north/south), widely reported in the area. North/south separation was the main signal in outlier loci, and the linage divergence at 39°S was subjacent. We conclude that the geographic structure of the genetic diversity of outlier and neutral loci was established by different strengths of environmental, historical and anthropogenic factors. PMID:28300177

  6. The Hemolymph of the ascidian Styela plicata (Chordata-Tunicata) contains heparin inside basophil-like cells and a unique sulfated galactoglucan in the plasma.

    PubMed

    de Barros, Cintia M; Andrade, Leonardo R; Allodi, Silvana; Viskov, Christian; Mourier, Pierre A; Cavalcante, Moisés C M; Straus, Anita H; Takahashi, Helio K; Pomin, Vitor H; Carvalho, Vinicius F; Martins, Marco A; Pavão, Mauro S G

    2007-01-19

    The hemolymph of ascidians (Chordata-Tunicata) contains different types of hemocytes embedded in a liquid plasma. In the present study, heparin and a sulfated heteropolysaccharide were purified from the hemolymph of the ascidian Styela plicata. The heteropolysaccharide occurs free in the plasma, is composed of glucose ( approximately 60%) and galactose ( approximately 40%), and is highly sulfated. Heparin, on the other hand, occurs in the hemocytes, and high performance liquid chromatography of the products formed by degradation with specific lyases revealed that it is composed mainly by the disaccharides DeltaUA(2SO(4))-1-->4-beta-d-GlcN(SO(4)) (39.7%) and DeltaUA(2SO(4))-1-->4-beta-d-GlcN(SO(4))(6SO(4)) (38.2%). Small amounts of the 3-O-sulfated disaccharides DeltaUA(2SO(4))-1-->4-beta-d-GlcN(SO(4))(3SO(4)) (9.8%) and DeltaUA(2SO(4))-1-->4-beta-d-GlcN(SO(4))(3SO(4))(6SO(4)) (3.8%) were also detected. These 3-O-sulfated disaccharides were demonstrated to be essential for the binding of the hemocyte heparin to antithrombin III. Electron microscopy techniques were used to characterize the ultrastructure of the hemocytes and to localize heparin and histamine in these cells. At least five cell types were recognized and classified as univacuolated and multivacuolated cells, amebocytes, hemoblasts, and granulocytes. Immunocytochemistry showed that heparin and histamine co-localize in intracellular granules of only one type of hemocyte, the granulocyte. These results show for the first time that in ascidians, a sulfated galactoglucan circulates free in the plasma, and heparin occurs as an intracellular product of a circulating basophil-like cell.

  7. Qibla in the Mediterranean

    NASA Astrophysics Data System (ADS)

    Rius-Piniés, Mònica

    Orientation toward Mecca has been compulsory for Muslims in all time periods and in all places. In fact, mosques were built in such a way as to help believers to pray toward the right direction. Nevertheless, the alignment of the sacred buildings was not always exact, and many did not actually face the Kaaba. There are many reasons for this "mistake", the main one being that at the time of the construction of the most important mosques, the astronomical and geographical knowledge needed to make accurate calculations was lacking. In the Mediterranean area, the scholars who were most involved in this task were the fuqahā' (experts in Islamic jurisprudence) who were sometimes well versed in astronomical knowledge or, at least, were skilled in the practice of popular astronomy. The combination of astronomy and religion, mixed with the political and topographical conditions, produces a unique area of study which remains controversial today.

  8. A new species of photosymbiotic ascidian from the Ryukyu Archipelago, Japan, with remarks on the stability of stigma number in photosymbiotic Diplosoma species.

    PubMed

    Hirose, Euichi; Oka, Atsushi T

    2008-12-01

    Diplosoma variostigmatum sp. nov. is a photosymbiotic ascidian in the family Didemnidae. This species is characterized by the unique pattern of its stigma number, which is often variable within the same zooid, as well as within the same colony. The total number of stigmata per half branchial sac varies from 22 (five, six, six, and five stigmata from the top to bottom rows) to 27 (seven, seven, seven, and six). In contrast, the stigma patterns are constant in D. ooru, D. simile, D. simileguwa, and D. virens. Thus, the stigma number and its stability (or variability) seem to be important as characters for the taxonomy of the photosymbiotic Diplosoma species.

  9. Familial Mediterranean Fever

    PubMed Central

    Migita, Kiyoshi; Agematsu, Kazunaga; Yazaki, Masahide; Nonaka, Fumiaki; Nakamura, Akinori; Toma, Tomoko; Kishida, Dai; Uehara, Ritei; Nakamura, Yoshikazu; Jiuchi, Yuka; Masumoto, Junya; Furukawa, Hiroshi; Ida, Hiroaki; Terai, Chihiro; Nakashima, Yoshikazu; Kawakami, Atsushi; Nakamura, Tadashi; Eguchi, Katsumi; Yasunami, Michio; Yachie, Akihiro

    2014-01-01

    Abstract Familial Mediterranean fever (FMF) is an autoinflammatory disease caused by MEditerranean FeVer gene (MEFV) mutations. In Japan, patients with FMF have been previously reported, including a mild or incomplete form. Several factors are presumed to contribute to the variable penetrance and to the phenotypic variability of FMF. We conducted the current study to investigate the correlation of variable clinical presentations and MEFV genotypic distributions in Japanese FMF patients. We analyzed demographic, clinical, and genetic data for 311 FMF patients enrolled in the study. Clinically, we classified FMF into 2 phenotypes: 1) the “typical” form of FMF, and 2) the “atypical” form of FMF according to the Tel Hashomer criteria. Patients with the typical FMF phenotype had a higher frequency of febrile episodes, a shorter duration of febrile attacks, more frequent thoracic pain, abdominal pain, a family history of FMF, and MEFV exon 10 mutations. Conversely, patients with the atypical FMF phenotype had a lower frequency of fever episodes and more frequent arthritis in atypical distribution, myalgia, and MEFV exon 3 mutations. Multivariate analysis showed that the variable associated with typical FMF presentation was the presence of MEFV exon 10 mutations. Typical FMF phenotype frequencies were decreased in patients carrying 2 or a single low-penetrance mutations compared with those carrying 2 or a single high-penetrance mutations (M694I), with an opposite trend for the atypical FMF phenotype. In addition, patients having more than 2 MEFV mutations had a younger disease onset and a higher prevalence of thoracic pain than those carrying a single or no mutations. Thus, MEFV exon 10 mutations are associated with the more typical FMF phenotype. In contrast, more than half of the Japanese FMF patients without MEFV exon 10 mutations presented with an atypical FMF phenotype, indicating that Japanese FMF patients tend to be divided into 2 phenotypes by a variation

  10. Symmetrical reproductive compatibility of two species in the Ciona intestinalis (Ascidiacea) species complex, a model for marine genomics and developmental biology.

    PubMed

    Sato, Atsuko; Shimeld, Sebastian M; Bishop, John D D

    2014-06-01

    The sea squirt Ciona intestinalis species complex is a widely used model system for genomics and developmental biology, as well as ecology. Contrary to previous reports, here we show no difference in the success of development and hatching between hybrid and conspecific crosses between the two species within this complex known as types A and B, from a region in the English Channel where they are sympatric. We grew laboratory hybrids in the field for three months, and successfully obtained reproductive adults. In back-crosses of F1 laboratory hybrids to parental types, normal larvae were obtained. We conclude that hybrid crosses generate viable offspring and the resulting hybrids are interfertile with types A and B. However we also show that introgression in the natural sympatric population remains low. We discuss possible pre-zygotic and post-zygotic mechanisms which reproductively isolate these species.

  11. Orthodontics in the Mediterranean Area.

    PubMed

    Calò, Claudia; Garino, Francesco; Cozzani, Mauro

    2006-01-01

    The article describes on the results of the first Workshop that SIDO organized in December 2005 in Cairo getting together twenty Countries who discussed Orthodontics in the Mediterranean Area. The aim was to take a picture, for the first time, of the state of Orthodontics in the different Mediterranean Countries using it as basis for a further co-operation. Progress in Orthodontics (published in English, indexed in Medline, free of charge website and downloading) was offered by SIDO as the means for a scientific and organizational sharing, and to spread a Mediterranean Orthodontic culture all over the world. The first step toward mutual understanding was completed and for the first time we collected data and the Mediterranean Orthodontic Integration Project (MOIP), on which we can base a coming meeting and debate, was introduced.

  12. Genomic Inprinting of the M6P/IGF2 Receptor: A Novel Breast Cancer Susceptibility Mechanism

    DTIC Science & Technology

    2001-07-01

    Nakayama • Yutaka Satou • Nori Satoh Isolation and characterization of genes that are expressed during Ciona intestinalis metamorphosis Received: 6...phosis in Ciona intestinalis . One of the tnes, Ci-metal, that a. initiated at the moment of settlement. According encodes a polypeptide with a putative...very Keywords Ascidians . etamorphosis .Genes. short p riod of time; the tail resorption of Ciona , for Cell signaling • Cell r arrangement example, is

  13. Cancer and Mediterranean dietary traditions.

    PubMed

    Trichopoulou, A; Lagiou, P; Kuper, H; Trichopoulos, D

    2000-09-01

    The incidence of cancer overall in Mediterranean countries is lower than in Scandinavian countries, the United Kingdom, and the United States. This is mostly accounted for by the lower incidence among Mediterranean countries of cancer of the large bowel, breast, endometrium, and prostate. These forms of cancer have been linked to dietary factors, particularly low consumption of vegetables and fruit, and to a certain extent, high consumption of meat. The traditional Mediterranean diet is characterized by high consumption of foods of plant origin, relatively low consumption of red meat, and high consumption of olive oil, which in several studies has been reported to be more beneficial against cancer than other forms of added lipids. By taking into account the established or presumed nutritional causation of major forms of cancer and the composition of the traditional Mediterranean diet, estimates can be derived concerning the fraction of cancer occurrence in highly developed Western countries that could be attributed to their diets in comparison with the healthy traditional Mediterranean diet. Although estimates can only be crude, it can be calculated that up to 25% of the incidence of colorectal cancer, approximately 15% of the incidence of breast cancer, and approximately 10% of the incidence of prostate, pancreas, and endometrial cancer could be prevented if the populations of highly developed Western countries could shift to the traditional healthy Mediterranean diet.

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

    PubMed

    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.

  15. NK4 Antagonizes Tbx1/10 to Promote Cardiac versus Pharyngeal Muscle Fate in the Ascidian Second Heart Field

    PubMed Central

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

    2013-01-01

    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. PMID:24311985

  16. Purification and characterization of a 39,000-Da serine proteinase from the hemolymph of a solitary ascidian, Halocynthia roretzi.

    PubMed

    Shishikura, F; Abe, T; Ohtake, S; Tanaka, K

    1997-09-01

    A new endogenous serine proteinase from the cell-free hemolymph of a solitary ascidian, Halocythia roretzi, was purified by a combination of ammonium sulfate fractionation, hydrophobic interaction chromatography on TSKgel Toyopearl HW 65 F, ion exchange chromatography on TSKgel DEAE-Toyopearl 650 M, affinity chromatography on Arginine-Sepharose 4B, gel filtration on TSKgel Toyopearl HW 65F and hydroxyapatite chromatography on Bio-Gel HT. The serine proteinase is a single polypeptide chain whose molecular weight and isoelectric point are 39 kDa and about 7.6 pI, respectively. The most susceptible substrate was Boc-Leu-Gly-Arg-4-methyl-coumaryl-7-amide (MCA), and activity was optimal at pH 8. The enzyme was relatively stable at high temperatures; about 50% activity was retained even at 60 degrees C for 30 min in 50 mM Tris-HCl, pH 8.0, containing 0.5 M NaCl, and 0.05% Brij-35. The enzyme was characterized by the inhibitory effects of synthetic or natural inhibitors, substrate specificity toward 26 peptidyl-MCAs, proteinase activity toward natural proteins and complex formation with a serine proteinase inhibitor (58 kDa) previously found in H. roretzi hemolymph, indicating that the enzyme was a member of serine proteinases and strongly inhibited by the 58 kDa serine proteinase inhibitor as well as human antithrombin III. We also demonstrated the clotting enzyme activity of the purified serine proteinase toward bovine fibrinogen and Limulus coagulogen, a fibrinogen-like clottable protein of horseshoe crabs.

  17. Epimerization of D-glucose to L-galactose during the biosynthesis of a sulfated L-galactan in the ascidian tunic

    SciTech Connect

    Mourao, P.A.S. )

    1991-04-09

    The sulfated polysaccharides occurring in the tunic of ascidians are unique among known sulfated polysaccharides in that their major constituent sugar is galactose, which occurs exclusively in the L-enantiomeric form. In vitro incorporation experiments using tunic slices incubated with {sup 14}C-labeled sugars revealed that cells from this tissue epimerize D-isomers of hexose into L-galactose during the biosynthesis of their constituent polysaccharides. Compared with other hexoses, the precursor D-({sup 14}C)glucose has the highest rate of incorporation and produces the highest proportion of L-galactose units. This metabolic pathway is distinct from the epimerization of D-mannose to L-galactose through its guanosine 5{prime}-diphosphate nucleotide, described previously in an alga and in a snail. Therefore, the epimerization of D-glucose to L-galactose in the ascidian tunic occurs through a novel metabolic route, which involves inversion of the configuration of carbon atoms 2, 3, and 5 of the hexosyl moieties.

  18. CIPRO 2.5: Ciona intestinalis protein database, a unique integrated repository of large-scale omics data, bioinformatic analyses and curated annotation, with user rating and reviewing functionality.

    PubMed

    Endo, Toshinori; Ueno, Keisuke; Yonezawa, Kouki; Mineta, Katsuhiko; Hotta, Kohji; Satou, Yutaka; Yamada, Lixy; Ogasawara, Michio; Takahashi, Hiroki; Nakajima, Ayako; Nakachi, Mia; Nomura, Mamoru; Yaguchi, Junko; Sasakura, Yasunori; Yamasaki, Chisato; Sera, Miho; Yoshizawa, Akiyasu C; Imanishi, Tadashi; Taniguchi, Hisaaki; Inaba, Kazuo

    2011-01-01

    The Ciona intestinalis protein database (CIPRO) is an integrated protein database for the tunicate species C. intestinalis. The database is unique in two respects: first, because of its phylogenetic position, Ciona is suitable model for understanding vertebrate evolution; and second, the database includes original large-scale transcriptomic and proteomic data. Ciona intestinalis has also been a favorite of developmental biologists. Therefore, large amounts of data exist on its development and morphology, along with a recent genome sequence and gene expression data. The CIPRO database is aimed at collecting those published data as well as providing unique information from unpublished experimental data, such as 3D expression profiling, 2D-PAGE and mass spectrometry-based large-scale analyses at various developmental stages, curated annotation data and various bioinformatic data, to facilitate research in diverse areas, including developmental, comparative and evolutionary biology. For medical and evolutionary research, homologs in humans and major model organisms are intentionally included. The current database is based on a recently developed KH model containing 36,034 unique sequences, but for higher usability it covers 89,683 all known and predicted proteins from all gene models for this species. Of these sequences, more than 10,000 proteins have been manually annotated. Furthermore, to establish a community-supported protein database, these annotations are open to evaluation by users through the CIPRO website. CIPRO 2.5 is freely accessible at http://cipro.ibio.jp/2.5.

  19. Adaptive evolution of Mediterranean pines.

    PubMed

    Grivet, Delphine; Climent, José; Zabal-Aguirre, Mario; Neale, David B; Vendramin, Giovanni G; González-Martínez, Santiago C

    2013-09-01

    Mediterranean pines represent an extremely heterogeneous assembly. Although they have evolved under similar environmental conditions, they diversified long ago, ca. 10 Mya, and present distinct biogeographic and demographic histories. Therefore, it is of special interest to understand whether and to what extent they have developed specific strategies of adaptive evolution through time and space. To explore evolutionary patterns, the Mediterranean pines' phylogeny was first reconstructed analyzing a new set of 21 low-copy nuclear genes with multilocus Bayesian tree reconstruction methods. Secondly, a phylogenetic approach was used to search for footprints of natural selection and to examine the evolution of multiple phenotypic traits. We identified two genes (involved in pines' defense and stress responses) that have likely played a role in the adaptation of Mediterranean pines to their environment. Moreover, few life-history traits showed historical or evolutionary adaptive convergence in Mediterranean lineages, while patterns of character evolution revealed various evolutionary trade-offs linking growth-development, reproduction and fire-related traits. Assessing the evolutionary path of important life-history traits, as well as the genomic basis of adaptive variation is central to understanding the past evolutionary success of Mediterranean pines and their future response to environmental changes.

  20. [Endemic zoonosis in Mediterranean area].

    PubMed

    Fenga, Concettina; Pugliese, Michela

    2013-01-01

    The Mediterranean is historically considered an area of high concentration of zoonoses. Mediterranean countries socio-economic features have favoured, over time, the onset of different types of zoonosis. Many of these may affect many occupational categories, first of all farmers, people working in abattoirs and processing products of animal origin. New farming activities and technologies have generated new occupational and zoonotic risks. These changes have influenced zoonosis epidemiology and have led to a gradual decrease in the number of diseases and to a reduction of some biological risks. However, brucellosis, Q fever, bovine tuberculosis cystic echinococcosis remain a strong example of zoonosis and a real risk, in the Mediterranean area especially. Therefore, an interdisciplinary collaboration between Veterinary Service, Public Health and Occupational medicine is necessary in order to plan territorial prevention.

  1. Predicting the Eastern Mediterranean Basin

    NASA Astrophysics Data System (ADS)

    Royden, L.

    2011-12-01

    From ~30 Ma onwards, the evolution of the Mediterranean region has been dominated by the rapid migration of thin-skinned thrust-belts. Thrust belt migration has been accommodated by the opening of "back arc type" basins within the upper plate of the thrust belts. Migration of these thrust belts is associated with the migration of subduction systems where subduction and thrusting are driven largely by negative slab buoyancy. Where the subducting slab has large negative buoyancy, thrust belt migration is commonly rapid. Where buoyant continental lithosphere enters the subduction system, subduction ceases quickly. Hence the large-scale tectonic evolution of the Mediterranean basin is largely pre-conditioned by its paleogeography. This can be quantitatively illustrated for the Hellenic subduction system where the post Eocene evolution of the Hellenic thrust belt can be ascribed to the buoyancy of the lithosphere subducted. Entry of the Ionian oceanic lithosphere into a slow-moving trench at 10-15 Ma explains the increase in subduction rate along the central part of the trench, to ~35 mm/yr at present, while subduction rates along strike to the northeast, where continental/transitional crust is subducted, remain less than ~10 mm/yr. Using quantitative modeling of the Hellenic subduction system in post Eocene time, it is possible to approximate how this thrust belt, and the active subduction belt of the eastern Mediterranean, will evolve over the next 10 m.y. This exercise suggests that the large-scale evolution of the eastern Mediterranean basin will be strikingly similar to that of the western Mediterranean basin from 20-0 Ma. This highlights the common dynamic mechanism that shapes the large scale deformation and morphology of the Mediterranean basin.

  2. Establishment and succession of an epibiotic community on chromated copper arsenate-treated wood in Mediterranean waters.

    PubMed

    Karayanni, Hera; Kormas, Konstantinos Ar; Cragg, Simon; Nicolaidou, Artemis

    2010-01-01

    Colonization and succession of an epibiotic animal community on chromated copper arsenate (CCA)-treated wood were studied for 18 months in the eastern Mediterranean (Saronikos Gulf, Aegean Sea). Pine wood panels, 200 x 100 x 25 mm, impregnated with CCA at retentions of 0, 12, 24, and 48 kg m(-3) were used. The abundance or surface coverage of the most characteristic taxa (polychaetes, mollusca, crustacea bryozoa, sponges, ascidians) was measured in situ, while 12 months after submersion two panels of each retention were removed and examined in the laboratory. A total of 26 taxa were identified, among which polychaetes of the family Serpulidae dominated. The controls carried the largest number of species (17) but the lowest number of individuals. On panels with CCA retentions of 12 and 24 kg m(-3), 14 and 16 species were observed, respectively, while at 48 kg m(-3), only 9 species were found. Only the controls were affected by boring bivalves of the family Teredinidae and started to break up within 3 months of submersion. Statistically significant differences in barnacle and polychaete abundance were found between treated and untreated panels. There were no significant differences among panels treated at the three CCA loadings. Ordination by nonmetric multidimensional scaling showed a seasonal effect on the colonization of the treated panels, with the highest recruitment during the warmer months of the study.

  3. Assessment of coastal marine pollution in Galicia (NW Iberian Peninsula); metal concentrations in seawater, sediments and mussels (Mytilus galloprovincialis) versus embryo-larval bioassays using Paracentrotus lividus and Ciona intestinalis.

    PubMed

    Beiras, R; Bellas, J; Fernández, N; Lorenzo, J I; Cobelo-García, A

    2003-10-01

    Sediments from three Galician Rias were tested for toxicity using sea-urchin and ascidian sediment elutriate embryo-larval bioassays. Trace metal contents in seawater, sediments and mussels were also determined and subjected to multidimensional scaling methods which grouped stations according to chemical contamination. High metal contents were found in seawater, sediments and mussels from the Ria of Pontevedra, and moderate levels were detected in the Ria of Vigo and Ria of Arousa. The results revealed that samples assessed as toxic, according to the sea-urchin and ascidian embryo-larval bioassays, were among the most polluted by trace metals. A good agreement was reported between ordination plots resulting from applying multidimensional scaling to the chemical data, and the results of the biological endpoints tested.

  4. Postfire chaparral regeneration under mediterranean and non-mediterranean climates

    USGS Publications Warehouse

    Keeley, Jon E.; Fotheringham, Connie J.; Rundel, Philip W.

    2012-01-01

    This study compares postfire regeneration and diversity patterns in fire-prone chaparral shrublands from mediterranean (California) and non-mediterranean-type climates (Arizona). Vegetation sampling was conducted in tenth hectare plots with nested subplots for the first two years after fire. Floras in the two regions were compared with Jaccard's Index and importance of families and genera compared with dominance-diversity curves. Although there were 44 families in common between the two regions, the dominant families differed; Poaceae and Fabaceae in Arizona and Hydrophyllaceae and Rosaceae in California. Dominance diversity curves indicated in the first year a more equable distribution of families in Arizona than in California. Woody plants were much more dominant in the mediterranean climate and herbaceous plants more dominant in the bimodal rainfall climate. Species diversity was comparable in both regions at the lowest spatial scales but not at the tenth hectare scale. Due to the double growing season in the non-mediterranean region, the diversity for the first year comprised two different herbaceous floras in the fall and spring growing seasons. The Mediterranean climate in California, in contrast, had only a spring growing season and thus the total diversity for the first year was significantly greater in Arizona than in California for both annuals and herbaceous perennials. Chaparral in these two climate regimes share many dominant shrub species but the postfire communities are very different. Arizona chaparral has both a spring and fall growing season and these produce two very different postfire floras. When combined, the total annual diversity was substantially greater in Arizona chaparral.

  5. Mediterranean Diet and Diabetes: Prevention and Treatment

    PubMed Central

    Georgoulis, Michael; Kontogianni, Meropi D.; Yiannakouris, Nikos

    2014-01-01

    The aim of the present review is to examine current scientific knowledge on the association between the Mediterranean diet and diabetes mellitus (mostly type 2 diabetes). A definition of the Mediterranean diet and the tools widely used to evaluate adherence to this traditional diet (Mediterranean diet indices) are briefly presented. The review focuses on epidemiological data linking adherence to the Mediterranean diet with the risk of diabetes development, as well as evidence from interventional studies assessing the effect of the Mediterranean diet on diabetes control and the management of diabetes-related complications. The above mentioned data are explored on the basis of evaluating the Mediterranean diet as a whole dietary pattern, rather than focusing on the effect of its individual components. Possible protective mechanisms of the Mediterranean diet against diabetes are also briefly discussed. PMID:24714352

  6. [Mediterranean diet: not only food].

    PubMed

    da Vico, Letizia; Agostini, Susanna; Brazzo, Silvia; Biffi, Barbara; Masini, Maria Luisa

    2012-09-01

    The proposal of a Mediterranean way of life is much more than advise how to eat. The Mediterranean Diet, a model of Sustainable Diet, is an example of how to combine personal choices, economic, social and cultural rights, protective of human health and the ecosystem. There is in fact fundamental interdependence between dietary requirements, nutritional recommendations, production and consumption of food. In literature studies and nutritional and epidemiological monitoring activities at national and international level have found a lack of adherence to this lifestyle, due to the spread of the economy, lifestyles of the Western type and globalization of the production and consumption. To encourage the spread of a culture and a constant practice of the Mediterranean Diet, there are some tools that are presented in this article. The Mediterranean Diet Pyramid in addition to the recommendations on the frequency and portions of food, focuses on the choice of how to cook and eat food. The "Double Food Pyramid" encourages conscious food choices based on "healthy eating and sustainability. All the nutrition professionals and dietitians in particular should be constantly striving to encourage the adoption of a sustainable and balanced nutrition.

  7. PON1 and Mediterranean Diet.

    PubMed

    Lou-Bonafonte, José M; Gabás-Rivera, Clara; Navarro, María A; Osada, Jesús

    2015-05-27

    The Mediterranean diet has been proven to be highly effective in the prevention of cardiovascular diseases. Paraoxonase 1 (PON1) has been implicated in the development of those conditions, especially atherosclerosis. The present work describes a systematic review of current evidence supporting the influence of Mediterranean diet and its constituents on this enzyme. Despite the differential response of some genetic polymorphisms, the Mediterranean diet has been shown to exert a protective action on this enzyme. Extra virgin olive oil, the main source of fat, has been particularly effective in increasing PON1 activity, an action that could be due to low saturated fatty acid intake, oleic acid enrichment of phospholipids present in high-density lipoproteins that favor the activity, and increasing hepatic PON1 mRNA and protein expressions induced by minor components present in this oil. Other Mediterranean diet constituents, such as nuts, fruits and vegetables, have been effective in modulating the activity of the enzyme, pomegranate and its compounds being the best characterized items. Ongoing research on compounds isolated from all these natural products, mainly phenolic compounds and carotenoids, indicates that some of them are particularly effective, and this may enhance the use of nutraceuticals and functional foods capable of potentiating PON1 activity.

  8. PON1 and Mediterranean Diet

    PubMed Central

    Lou-Bonafonte, José M.; Gabás-Rivera, Clara; Navarro, María A.; Osada, Jesús

    2015-01-01

    The Mediterranean diet has been proven to be highly effective in the prevention of cardiovascular diseases. Paraoxonase 1 (PON1) has been implicated in the development of those conditions, especially atherosclerosis. The present work describes a systematic review of current evidence supporting the influence of Mediterranean diet and its constituents on this enzyme. Despite the differential response of some genetic polymorphisms, the Mediterranean diet has been shown to exert a protective action on this enzyme. Extra virgin olive oil, the main source of fat, has been particularly effective in increasing PON1 activity, an action that could be due to low saturated fatty acid intake, oleic acid enrichment of phospholipids present in high-density lipoproteins that favor the activity, and increasing hepatic PON1 mRNA and protein expressions induced by minor components present in this oil. Other Mediterranean diet constituents, such as nuts, fruits and vegetables, have been effective in modulating the activity of the enzyme, pomegranate and its compounds being the best characterized items. Ongoing research on compounds isolated from all these natural products, mainly phenolic compounds and carotenoids, indicates that some of them are particularly effective, and this may enhance the use of nutraceuticals and functional foods capable of potentiating PON1 activity. PMID:26024295

  9. Two new species of photosymbiotic ascidians of the genus Diplosoma from the Ryukyu Archipelago, with partial sequences of the COI gene.

    PubMed

    Hirose, Euichi; Oka, Atsushi T; Hirose, Mamiko

    2009-05-01

    Two new species of Diplosoma are described from coral reefs in the Ryukyu Archipelago, Japan: D. watanabei sp. nov. and D. gumavirens sp. nov. Colonies of both species are green due to algal symbionts of Prochloron, which are distributed in the common cloacal cavity. Both species are characterized by the point of emergence of the retractor muscle and a unique combination of stigma numbers among the four rows of the branchial sac. There are three adhesive papillae in the embryos of D. watanabei, as in most ascidian embryos and larvae, whereas the pre-hatching embryos of D. gumavirens sp. nov. posses 12-16 adhesive papillae. Partial sequences of the cytochrome c oxidase subunit I (COI) gene discriminated the new species from each other and from congeners.

  10. An ultraviolet-sensitive maternal mRNA encoding a cytoskeletal protein may be involved in axis formation in the ascidian embryo

    SciTech Connect

    Jeffery, W.R. )

    1990-09-01

    Ultraviolet (uv) irradiation of the vegetal hemisphere of fertilized eggs during ooplasmic segregation inhibits subsequent gastrulation and axis formation in ascidian embryos. The molecular basis of this phenomenon was investigated in by comparing in vivo protein synthesis and in vitro mRNA translation in normal and uv-irradiated embryos of the ascidian Styela clava. Analysis of protein synthesis by (35S)methionine incorporation, two-dimensional (2D) gel electrophoresis, and autoradiography showed that only 21 of 433 labeled polypeptides were missing or decreased in labeling intensity in uv-irradiated embryos. The most prominent of these was a 30,000 molecular weight (pI 6.0) polypeptide (p30). Extraction of gastrulae with the nonionic detergent Triton X-100 showed that p30 is retained in the detergent insoluble residue, suggesting that it is associated with the cytoskeleton. Several lines of evidence suggest that p30 may be involved in axis formation. First, p30 labeling peaks during gastrulation, when the embryonic axis is being established. Second, axis formation and p30 labeling are abolished by the same threshold uv dose, which is distinct from that required to inactivate muscle cell development. Third, the uv sensitivity period for abolishing p30 labeling and axis formation are both restricted to ooplasmic segregation. In vitro translation of egg RNA followed by 2D gel electrophoresis and autoradiography of the protein products showed that p30 is encoded by a maternal mRNA. The translation of p30 mRNA was abolished by uv irradiation of fertilized eggs during ooplasmic segregation suggesting that this message is a uv-sensitive target. The results are consistent with the hypothesis that uv irradiation blocks gastrulation and axis formation by inhibiting the translation of maternal mRNA localized in the vegetal hemisphere of the fertilized egg.

  11. Structural investigations of the p53/p73 homologs from the tunicate species Ciona intestinalis reveal the sequence requirements for the formation of a tetramerization domain.

    PubMed

    Heering, Jan; Jonker, Hendrik R A; Löhr, Frank; Schwalbe, Harald; Dötsch, Volker

    2016-02-01

    Most members of the p53 family of transcription factors form tetramers. Responsible for determining the oligomeric state is a short oligomerization domain consisting of one β-strand and one α-helix. With the exception of human p53 all other family members investigated so far contain a second α-helix as part of their tetramerization domain. Here we have used nuclear magnetic resonance spectroscopy to characterize the oligomerization domains of the two p53-like proteins from the tunicate Ciona intestinalis, representing the closest living relative of vertebrates. Structure determination reveals for one of the two proteins a new type of packing of this second α-helix on the core domain that was not predicted based on the sequence, while the other protein does not form a second helix despite the presence of crucial residues that are conserved in all other family members that form a second helix. By mutational analysis, we identify a proline as well as large hydrophobic residues in the hinge region between both helices as the crucial determinant for the formation of a second helix.

  12. Characterization of the teneurin C-terminal associated peptide (TCAP) in the vase tunicate, Ciona intestinalis: A novel peptide system associated with energy metabolism and reproduction.

    PubMed

    Colacci, Michael; De Almeida, Reuben; Chand, Dhan; Lovejoy, Sabine R; Sephton, Dawn; Vercaemer, Benedikte; Lovejoy, David A

    2015-05-15

    The vase tunicate, Ciona intestinalis, is a protochordate and is considered a sister lineage to the chordates. The recent sequencing of its genome has made this species a particularly important model to understand the genetic basis of vertebrate evolution. However, C. intestinalis is also a highly invasive species along the Atlantic coast of North America and other regions of the world which have caused considerable economic stress due to its biofouling actions and, in particular, negative impacts on the mussel- and oyster-based aquaculture industry. Despite this background, little is known about C. intestinalis physiology. The teneurin C-terminal associated peptides (TCAP) are a family of highly conserved peptide hormones found in most metazoans. Moreover, these peptides have been implicated in the inhibition of stress and stimulation of feeding-based metabolism. We have, therefore, identified this peptide using an in silico approach and characterized its immunological expression in tissues using a mouse polyclonal antiserum. These data indicate that its primary structure is more similar to invertebrate TCAPs relative to vertebrate TCAPs. Immunological expression indicates that it is highly expressed in the digestive tract and gonads consistent with findings in vertebrates. Synthetic mouse TCAP-1 administered into the brachial basket significantly increases the incidence of non-stress contractile behaviors. These findings support the hypothesis that TCAP is a bioactive peptide in C. intestinalis. Thus, C. intestinalis and tunicates in general may offer a simple model to investigate peptide interaction while providing information on how to control this invasive species.

  13. Ciona intestinalis galectin (CiLgals-a and CiLgals-b) genes are differentially expressed in endostyle zones and challenged by LPS.

    PubMed

    Parrinello, Daniela; Sanfratello, Maria Antonietta; Vizzini, Aiti; Parrinello, Nicolò; Cammarata, Matteo

    2015-01-01

    Immunohistochemical and in situ hybridization assays were performed to answer the question whether the endostyle, that is the initial gastro-intestinal trait of Ciona intestinalis pharynx, is involved in galectin (CiLgals-a and CiLgals-b) production during the pharynx inflammatory response to LPS inoculation. Specific anti-CiLgal-a and anti-CiLgals-b antibodies, and oligonucleotide probes, that mark inflammatory hemocytes inside the pharynx vessels and vessel epithelium as shown by a previous paper, were assayed on endostyle histological sections. For the first time, we show that galectins are produced by endostyle zones, and both CiLgals-a and -b genes are upregulated by LPS. CiLgals-a and CiLgals-b are constitutively expressed in the endostyle zone 2 and 3, respectively, both genes are upregulated by LPS in the zone 2, and CiLgals-b in the zone 3 and 4. The antibody-reacting material contained in intracellular and extracellular large vesicles suggest an unexpected vesicle-dependent transporting mechanism of galectins not provided with signal peptide. Differential expression and gene upregulation in not-treated and LPS-treated specimens, support the role of endostyle galectins both in filter feeding and defense responses.

  14. Fire regime in Mediterranean ecosystem

    NASA Astrophysics Data System (ADS)

    Biondi, Guido; Casula, Paolo; D'Andrea, Mirko; Fiorucci, Paolo

    2010-05-01

    The analysis of burnt areas time series in Mediterranean regions suggests that ecosystems characterising this area consist primarily of species highly vulnerable to the fire but highly resilient, as characterized by a significant regenerative capacity after the fire spreading. In a few years the area burnt may once again be covered by the same vegetation present before the fire. Similarly, Mediterranean conifer forests, which often refers to plantations made in order to reforest the areas most severely degraded with high erosion risk, regenerate from seed after the fire resulting in high resilience to the fire as well. Only rarely, and usually with negligible damages, fire affects the areas covered by climax species in relation with altitude and soil types (i.e, quercus, fagus, abies). On the basis of these results, this paper shows how the simple Drossel-Schwabl forest fire model is able to reproduce the forest fire regime in terms of number of fires and burned area, describing whit good accuracy the actual fire perimeters. The original Drossel-Schwabl model has been slightly modified in this work by introducing two parameters (probability of propagation and regrowth) specific for each different class of vegetation cover. Using model selection methods based on AIC, the model with the optimal number of classes with different fire behaviour was selected. Two different case studies are presented in this work: Regione Liguria and Regione Sardegna (Italy). Both regions are situated in the center of the Mediterranean and are characterized by a high number of fires and burned area. However, the two regions have very different fire regimes. Sardinia is affected by the fire phenomenon only in summer whilst Liguria is affected by fires also in winter, with higher number of fires and larger burned area. In addition, the two region are very different in vegetation cover. The presence of Mediterranean conifers, (Pinus Pinaster, Pinus Nigra, Pinus halepensis) is quite spread in

  15. Handbook for Forecasters in the Mediterranean. Part 2. Regional Forecasting Aids for the Mediterranean Basin.

    DTIC Science & Technology

    1980-12-01

    Occurrences.....................11-7 3. Forecasting Rules.........................11-11 III. TYRRHENIAN SEA - CENTRAL MEDITERRANEAN AREA...the Tyrrhenian Sea -Central Mediterranean Area addressed in Section II1. A complex coastal topography characterizes the north and the south coasts of...is only 3 n mi. 11-25 III. TYRRHENIAN SEA - CENTRAL MEDITERRANEAN AREA 1. OVERVIEW 1.1 REGIONAL GEOGRAPHY The Tyrrhenian Sea -Central Mediterranean

  16. Mediterranean outflow mixing and dynamics.

    PubMed

    Price, J F; Baringer, M O; Lueck, R G; Johnson, G C; Ambar, I; Parrilla, G; Cantos, A; Kennelly, M A; Sanford, T B

    1993-02-26

    The Mediterranean Sea produces a salty, dense outflow that is strongly modified by entrainment as it first begins to descend the continental slope in the eastern Gulf of Cadiz. The current accelerates to 1.3 meters per second, which raises the internal Froude number above 1, and is intensely turbulent through its full thickness. The outflow loses about half of its density anomaly and roughly doubles its volume transport as it entrains less saline North Atlantic Central water. Within 100 kilometers downstream, the current is turned by the Coriolis force until it flows nearly parallel to topography in a damped geostrophic balance. The mixed Mediterranean outflow continues westward, slowly descending the continental slope until it becomes neutrally buoyant in the thermocline where it becomes an important water mass.

  17. Treatment of Mediterranean visceral leishmaniasis.

    PubMed Central

    Gradoni, L.; Bryceson, A.; Desjeux, P.

    1995-01-01

    Up-to-date information is given on the epidemiological situation of zoonotic visceral leishmaniasis (ZVL) in nine Mediterranean countries, and on drug regimens adopted in the management of ZVL patients in each country. Results of experimental and clinical trials on the efficacy and tolerability of liposomal amphotericin B in laboratory animals and in patients with ZVL are presented, as well as conclusions and recommendations on drug regimens to be used in the treatment of ZVL. PMID:7743590

  18. [Amyloidosis and familial Mediterranean fever].

    PubMed

    Pras, M

    1986-01-01

    Familial Mediterranean Fever (F. M. F.) is an autosomal recessive disorder occurring most commonly in Sepharadi Jews and Armenians. Two phenotypic features characterize the disease: brief episodic febrile attacks of peritonitis, pleuritis or synovitis recurring from childhood or adolescence and the development of systemic amyloidosis. Attacks are accompanied by striking elevations of acute phase proteins, including serum amyloid A protein. The amyloidosis of Familial Mediterranean Fever is of the AA type, and manifest clinically as a nephropathy that passes through proteinuria, nephrotic and uremic stages to renal death. Although there is ethnic variation in the incidence of amyloidosis of F. M. F. in our patient population--predominantly Sepharadi Jews of North African extraction--an amyloidotic death at an early age is their genetic destiny. Since the introduction in 1972 of colchicine to prevent the febrile attacks, the drug has been proven and become the main stay of therapy. Today, colchicine has been shown to be effective in preventing amyloidosis as well as the febrile attacks in Familial Mediterranean Fever. End stage renal disease is not the end of the road for patients with F.M.F. because of improving outlook for dialysis and renal transplantation in these patients.

  19. Mantle dynamics in the Mediterranean

    NASA Astrophysics Data System (ADS)

    Faccenna, Claudio; Becker, Thorsten W.

    2016-04-01

    The Mediterranean offers a unique avenue to study the driving forces of tectonic deformation within a complex mobile belt. Lithospheric dynamics are affected by slab rollback and collision of two large, slowly moving plates, forcing fragments of continental and oceanic lithosphere to interact. Here, we review the rich and growing set of constraints from geological reconstructions, geodetic data, and crustal and upper mantle heterogeneity imaged by structural seismology. We discuss a conceptual and quantitative framework for the causes of surface deformations. Exploring existing and newly developed tectonic and numerical geodynamic models, we illustrate the role of mantle convection on surface geology. A coherent picture emerges which can be outlined by two, almost symmetric, upper mantle convection cells. The down-wellings are found in the centre of the Mediterranean, and are associated with the descent of the Tyrrhenian and the Hellenic slabs. During plate convergence, these slabs migrated, driving return flow of the asthenosphere from the backarc regions. These currents can be found at large distance from the subduction zones, and are at present expressed in two upwellings beneath Anatolia and eastern Iberia. This convection system provides an explanation for the general pattern of seismic anisotropy in the Mediterranean, the first-order Anatolia and Adria microplate kinematics, and the positive dynamic topography of Anatolia and Eastern Iberia. More generally, it is an illustration of upper mantle, small-scale convection leading to intraplate deformation and complex plate boundary reconfiguration at the westernmost terminus of the Tethyan collision.

  20. Mediterranean Ocean Colour Chlorophyll trend

    NASA Astrophysics Data System (ADS)

    rinaldi, eleonora; colella, simone; santoleri, rosalia

    2014-05-01

    Monitoring chlorophyll (Chl) concentration, seen as a proxy for phytoplankton biomass, is an efficient tool in order to understand the response of marine ecosystem to human pressures. This is particularly important along the coastal regions, in which the strong anthropization and the irrational exploitation of resources represent a persistent threat to the biodiversity. The aim of this work is to assess the effectiveness and feasibility of using Ocean Color (OC) data to monitor the environmental changes in Mediterranean Sea and to develop a method for detecting trend from OC data that can constitute a new indicator of the water quality within the EU Marine Strategy Framework Directive implementation. In this study the Mediterranean merged Case1-Case2 chlorophyll product, produced by CNR-ISAC and distributed in the framework of MyOcean, is analyzed. This product is obtained by using two different bio-optical algorithms for open ocean (Case1) and coastal turbid (Case2) waters; this improves the quality of the Chl satellite estimates, especially near the coast. In order to verify the real capability of the this product for estimating Chl trend and for selecting the most appropriated statistical test to detect trend in the Mediterranean Sea, a comparison between OC and in situ data are carried out. In-situ Chl data are part of the European Environment Information and Observation Network (Eionet) of the European Environmental Agency (EEA). Four different statistical approaches to estimate trend have been selected and used to compare trend values obtained with in-situ and OC data. Results show that the best agreement between in-situ and OC trend is achieved using the Mann- Kendall test. The Mediterranean trend map obtained applying this test to the de-seasonalized OC time series shows that, in accordance with the results of many authors, the case 1 waters of Mediterranean sea are characterized by a negative trend. However, the most intense trend signals, both negative

  1. The formation and positioning of cilia in Ciona intestinalis embryos in relation to the generation and evolution of chordate left-right asymmetry.

    PubMed

    Thompson, Helen; Shaw, Michael K; Dawe, Helen R; Shimeld, Sebastian M

    2012-04-15

    In the early mouse embryo monocilia on the ventral node rotate to generate a leftward flow of fluid. This nodal flow is essential for the left-sided expression of nodal and pitx2, and for subsequent asymmetric organ patterning. Equivalent left fluid flow has been identified in other vertebrates, including Xenopus and zebrafish, indicating it is an ancient vertebrate mechanism. Asymmetric nodal and Pitx expression have also been identified in several invertebrates, including the vertebrates' nearest relatives, the urochordates. However whether cilia regulate this asymmetric gene expression remains unknown, and previous studies in urochordates have not identified any cilia prior to the larval stage, when asymmetry is already long established. Here we use Scanning and Transmission Electron Microscopy and immunofluorescence to investigate cilia in the urochordate Ciona intestinalis. We show that single cilia are transiently present on each ectoderm cell of the late neurula/early tailbud stage embryo, a time point just before onset of asymmetric nodal expression. Mapping the position of each cilium on these cells shows they are posteriorly positioned, something also described for mouse node cilia. The C. intestinalis cilia have a 9+0 ring ultrastructure, however we find no evidence of structures associated with motility such as dynein arms, radial spokes or nexin. Furthermore the 9+0 ring structure becomes disorganised immediately after the cilia have exited the cell, indicative of cilia which are not capable of motility. Our results indicate that although cilia are present prior to molecular asymmetries, they are not motile and hence cannot be operating in the same way as the flow-generating cilia of the vertebrate node. We conclude that the cilia may have a role in the development of C. intestinalis left-right asymmetry but that this would have to be in a sensory capacity, perhaps as mechanosensors as hypothesised in two-cilia physical models of vertebrate cilia

  2. Plate tectonics of the Mediterranean region.

    PubMed

    McKenzie, D P

    1970-04-18

    The seismicity and fault plane solutions in the Mediterranean area show that two small rapidly moving plates exist in the Eastern Mediterranean, and such plates may be a common feature of contracting ocean basins. The results show that the concepts of plate tectonics apply to instantaneous motions across continental plate boundaries.

  3. Gadolinium, a mechano-sensitive channel blocker, inhibits osmosis-initiated motility of sea- and freshwater fish sperm, but does not affect human or ascidian sperm motility.

    PubMed

    Krasznai, Zoltán; Morisawa, Masaaki; Krasznai, Zoárd Tibor; Morisawa, Sachiko; Inaba, Kazuo; Bazsáné, Zsuzsa Kassai; Rubovszky, Bálint; Bodnár, Béla; Borsos, Antal; Márián, Teréz

    2003-08-01

    Exposure to hypo-osmotic or hyperosmotic environment triggers the initiation of fish sperm motility. In this article, we report that calcium and potassium channel blockers do not influence motility of puffer fish sperm but calmodulin antagonists reversibly decrease it, suggesting that calmodulin-Ca(2+) interactions are prerequisite for the initiation of sperm motility in this species. Gadolinium (a stretch activated ion channel blocker) decreased the motility of puffer fish sperm from 92 +/- 3% to 6 +/- 3% and that of carp sperm from 91 +/- 7% to 3.5 +/- 4.3% in a dose-dependent manner (10-40 micro M). The effect of gadolinium was reversible, suggesting that stretch activated ion channels participate in the initiation of sperm motility of the two species. Gadolinium inhibits changes in the isoelectric point of certain proteins of puffer fish sperm, which occur when sperm motility is initiated in a hypertonic solution. Anisotropy measurements showed that hypo-osmotic treatment, which initiates carp sperm motility, increased membrane fluidity. When hypo-osmotic treatment was given in the presence of gadolinium, the sperm membrane remained as rigid as in quiescent cells, while motility was blocked. By contrast, gadolinium did not influence the motility parameters of Ciona or human sperm. Based on these lines of evidence, we suggest that conformational changes of mechanosensitive membrane proteins are involved in osmolality-dependent but not osmolality-independent sperm.

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

    PubMed Central

    Mochizuki, Atsushi; Satou, Yutaka

    2015-01-01

    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. PMID:26714026

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

    PubMed

    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.

  6. The Mediterranean Plastic Soup: synthetic polymers in Mediterranean surface waters.

    PubMed

    Suaria, Giuseppe; Avio, Carlo G; Mineo, Annabella; Lattin, Gwendolyn L; Magaldi, Marcello G; Belmonte, Genuario; Moore, Charles J; Regoli, Francesco; Aliani, Stefano

    2016-11-23

    The Mediterranean Sea has been recently proposed as one of the most impacted regions of the world with regards to microplastics, however the polymeric composition of these floating particles is still largely unknown. Here we present the results of a large-scale survey of neustonic micro- and meso-plastics floating in Mediterranean waters, providing the first extensive characterization of their chemical identity as well as detailed information on their abundance and geographical distribution. All particles >700 μm collected in our samples were identified through FT-IR analysis (n = 4050 particles), shedding for the first time light on the polymeric diversity of this emerging pollutant. Sixteen different classes of synthetic materials were identified. Low-density polymers such as polyethylene and polypropylene were the most abundant compounds, followed by polyamides, plastic-based paints, polyvinyl chloride, polystyrene and polyvinyl alcohol. Less frequent polymers included polyethylene terephthalate, polyisoprene, poly(vinyl stearate), ethylene-vinyl acetate, polyepoxide, paraffin wax and polycaprolactone, a biodegradable polyester reported for the first time floating in off-shore waters. Geographical differences in sample composition were also observed, demonstrating sub-basin scale heterogeneity in plastics distribution and likely reflecting a complex interplay between pollution sources, sinks and residence times of different polymers at sea.

  7. The Mediterranean Plastic Soup: synthetic polymers in Mediterranean surface waters

    PubMed Central

    Suaria, Giuseppe; Avio, Carlo G.; Mineo, Annabella; Lattin, Gwendolyn L.; Magaldi, Marcello G.; Belmonte, Genuario; Moore, Charles J.; Regoli, Francesco; Aliani, Stefano

    2016-01-01

    The Mediterranean Sea has been recently proposed as one of the most impacted regions of the world with regards to microplastics, however the polymeric composition of these floating particles is still largely unknown. Here we present the results of a large-scale survey of neustonic micro- and meso-plastics floating in Mediterranean waters, providing the first extensive characterization of their chemical identity as well as detailed information on their abundance and geographical distribution. All particles >700 μm collected in our samples were identified through FT-IR analysis (n = 4050 particles), shedding for the first time light on the polymeric diversity of this emerging pollutant. Sixteen different classes of synthetic materials were identified. Low-density polymers such as polyethylene and polypropylene were the most abundant compounds, followed by polyamides, plastic-based paints, polyvinyl chloride, polystyrene and polyvinyl alcohol. Less frequent polymers included polyethylene terephthalate, polyisoprene, poly(vinyl stearate), ethylene-vinyl acetate, polyepoxide, paraffin wax and polycaprolactone, a biodegradable polyester reported for the first time floating in off-shore waters. Geographical differences in sample composition were also observed, demonstrating sub-basin scale heterogeneity in plastics distribution and likely reflecting a complex interplay between pollution sources, sinks and residence times of different polymers at sea. PMID:27876837

  8. The Mediterranean Plastic Soup: synthetic polymers in Mediterranean surface waters

    NASA Astrophysics Data System (ADS)

    Suaria, Giuseppe; Avio, Carlo G.; Mineo, Annabella; Lattin, Gwendolyn L.; Magaldi, Marcello G.; Belmonte, Genuario; Moore, Charles J.; Regoli, Francesco; Aliani, Stefano

    2016-11-01

    The Mediterranean Sea has been recently proposed as one of the most impacted regions of the world with regards to microplastics, however the polymeric composition of these floating particles is still largely unknown. Here we present the results of a large-scale survey of neustonic micro- and meso-plastics floating in Mediterranean waters, providing the first extensive characterization of their chemical identity as well as detailed information on their abundance and geographical distribution. All particles >700 μm collected in our samples were identified through FT-IR analysis (n = 4050 particles), shedding for the first time light on the polymeric diversity of this emerging pollutant. Sixteen different classes of synthetic materials were identified. Low-density polymers such as polyethylene and polypropylene were the most abundant compounds, followed by polyamides, plastic-based paints, polyvinyl chloride, polystyrene and polyvinyl alcohol. Less frequent polymers included polyethylene terephthalate, polyisoprene, poly(vinyl stearate), ethylene-vinyl acetate, polyepoxide, paraffin wax and polycaprolactone, a biodegradable polyester reported for the first time floating in off-shore waters. Geographical differences in sample composition were also observed, demonstrating sub-basin scale heterogeneity in plastics distribution and likely reflecting a complex interplay between pollution sources, sinks and residence times of different polymers at sea.

  9. Importance of United States Naval Forward Presence in Mediterranean Affairs

    DTIC Science & Technology

    2001-06-01

    Mediterranean Region, and beyond. 24 This theme is developed by Fernand Braudel , The Mediterranean and...Relations,” Janes Intelligence Review, v. 13, no. 2, February 2000. Braudel , Fernand , “The Mediterranean and the Mediterranean World in the Age of

  10. Mitochondrial inhibitor sodium azide inhibits the reorganization of mitochondria-rich cytoplasm and the establishment of the anteroposterior axis in ascidian embryo.

    PubMed

    Ishii, Hirokazu; Shirai, Takuma; Makino, Chisato; Nishikata, Takahito

    2014-02-01

    In ascidian eggs, cytoplasmic and cortical reorganization, previously called ooplasmic segregation, occurs in two phases during the first cell cycle. In the second phase of reorganization, the mitochondria-rich cytoplasm (myoplasm) moves to the future posterior side, concurrent with sperm aster migration along the egg cortex. Although this reorganization is the critical step for establishing the anteroposterior axis, its molecular mechanism is not fully understood. In this study, we showed that low concentrations of the mitochondrial inhibitor sodium azide (NaN3 ), which showed the low toxicity in sperm, inhibited the second phase of reorganization without the microtubule depolymerization. In the NaN3 -treated embryo, the sperm aster was not attracted to the cortex and altered its migration pathway; therefore, the myoplasm remained at the vegetal pole. Consequently, the anteroposterior axis was not established. Another mitochondrial inhibitor, oligomycin, did not affect these processes. These results suggest that NaN3 inhibits unknown molecules that are important for the second phase of reorganization. Identifying the target molecule of NaN3 will lead to a molecular understanding of cytoplasmic and cortical reorganization.

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

    PubMed Central

    Estay, Sergio A.; Labra, Fabio A.; Lima, Mauricio

    2015-01-01

    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 suitable for

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

    PubMed

    Januario, Stella M; Estay, Sergio A; Labra, Fabio A; Lima, Mauricio

    2015-01-01

    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 suitable for

  13. Metagenomes of Mediterranean coastal lagoons.

    PubMed

    Ghai, Rohit; Hernandez, Claudia Mella; Picazo, Antonio; Mizuno, Carolina Megumi; Ininbergs, Karolina; Díez, Beatriz; Valas, Ruben; DuPont, Christopher L; McMahon, Katherine D; Camacho, Antonio; Rodriguez-Valera, Francisco

    2012-01-01

    Coastal lagoons, both hypersaline and freshwater, are common, but still understudied ecosystems. We describe, for the first time, using high throughput sequencing, the extant microbiota of two large and representative Mediterranean coastal lagoons, the hypersaline Mar Menor, and the freshwater Albufera de Valencia, both located on the south eastern coast of Spain. We show there are considerable differences in the microbiota of both lagoons, in comparison to other marine and freshwater habitats. Importantly, a novel uncultured sulfur oxidizing Alphaproteobacteria was found to dominate bacterioplankton in the hypersaline Mar Menor. Also, in the latter prokaryotic cyanobacteria were almost exclusively comprised by Synechococcus and no Prochlorococcus was found. Remarkably, the microbial community in the freshwaters of the hypertrophic Albufera was completely in contrast to known freshwater systems, in that there was a near absence of well known and cosmopolitan groups of ultramicrobacteria namely Low GC Actinobacteria and the LD12 lineage of Alphaproteobacteria.

  14. Familial Mediterranean fever: current perspectives

    PubMed Central

    Sönmez, Hafize Emine; Batu, Ezgi Deniz; Özen, Seza

    2016-01-01

    Familial Mediterranean fever (FMF) is the most frequent monogenic autoinflammatory disease, and it is characterized by recurrent attacks of fever and polyserositis. The disease is associated with mutations in the MEFV gene encoding pyrin, which causes exaggerated inflammatory response through uncontrolled production of interleukin 1. The major long-term complication of FMF is amyloidosis. Colchicine remains the principle therapy, and the aim of treatment is to prevent acute attacks and the consequences of chronic inflammation. With the evolution in the concepts about the etiopathogenesis and genetics of the disease, we have understood that FMF is more complicated than an ordinary autosomal recessive monogenic disorder. Recently, recommendation sets have been generated for interpretation of genetic testing and genetic diagnosis of FMF. Here, we have reviewed the current perspectives in FMF in light of recent recommendations. PMID:27051312

  15. Metagenomes of Mediterranean Coastal Lagoons

    PubMed Central

    Ghai, Rohit; Hernandez, Claudia Mella; Picazo, Antonio; Mizuno, Carolina Megumi; Ininbergs, Karolina; Díez, Beatriz; Valas, Ruben; DuPont, Christopher L.; McMahon, Katherine D.; Camacho, Antonio; Rodriguez-Valera, Francisco

    2012-01-01

    Coastal lagoons, both hypersaline and freshwater, are common, but still understudied ecosystems. We describe, for the first time, using high throughput sequencing, the extant microbiota of two large and representative Mediterranean coastal lagoons, the hypersaline Mar Menor, and the freshwater Albufera de Valencia, both located on the south eastern coast of Spain. We show there are considerable differences in the microbiota of both lagoons, in comparison to other marine and freshwater habitats. Importantly, a novel uncultured sulfur oxidizing Alphaproteobacteria was found to dominate bacterioplankton in the hypersaline Mar Menor. Also, in the latter prokaryotic cyanobacteria were almost exclusively comprised by Synechococcus and no Prochlorococcus was found. Remarkably, the microbial community in the freshwaters of the hypertrophic Albufera was completely in contrast to known freshwater systems, in that there was a near absence of well known and cosmopolitan groups of ultramicrobacteria namely Low GC Actinobacteria and the LD12 lineage of Alphaproteobacteria. PMID:22778901

  16. Mediterranean Ocean Colour Chlorophyll Trends

    PubMed Central

    Colella, Simone; Falcini, Federico; Rinaldi, Eleonora; Sammartino, Michela; Santoleri, Rosalia

    2016-01-01

    In being at the base of the marine food web, phytoplankton is particularly important for marine ecosystem functioning (e.g., biodiversity). Strong anthropization, over-exploitation of natural resources, and climate change affect the natural amount of phytoplankton and, therefore, represent a continuous threat to the biodiversity in marine waters. In particular, a concerning risks for coastal waters is the increase in nutrient inputs of terrestrial/anthropogenic origin that can lead to undesirable modifications of phytoplankton concentration (i.e., eutrophication). Monitoring chlorophyll (Chl) concentration, which is a proxy of phytoplankton biomass, is an efficient tool for recording and understanding the response of the marine ecosystem to human pressures and thus for detecting eutrophication. Here, we compute Chl trends over the Mediterranean Sea by using satellite data, also highlighting the fact that remote sensing may represent an efficient and reliable solution to synoptically control the “good environmental status” (i.e., the Marine Directive to achieve Good Environmental Status of EU marine waters by 2020) and to assess the application of international regulations and environmental directives. Our methodology includes the use of an ad hoc regional (i.e., Mediterranean) algorithm for Chl concentration retrieval, also accounting for the difference between offshore (i.e., Case I) and coastal (i.e., Case II) waters. We apply the Mann-Kendall test and the Sens’s method for trend estimation to the Chl concentration de-seasonalized monthly time series, as obtained from the X-11 technique. We also provide a preliminary analysis of some particular trends by evaluating their associated inter-annual variability. The high spatial resolution of our approach allows a clear identification of intense trends in those coastal waters that are affected by river outflows. We do not attempt to attribute the observed trends to specific anthropogenic events. However, the

  17. Night Views Over the Mediterranean Sea

    NASA Video Gallery

    This video over the Mediterranean Sea was taken by the crew of Expedition 29 aboard the International Space Station. This sequence of shots was taken on Oct. 6, 2011, from 22:58:09 to 23:13:15 GMT,...

  18. New hexactinellid sponges from deep Mediterranean canyons.

    PubMed

    Boury-Esnault, Nicole; Vacelet, Jean; Dubois, Maude; Goujard, Adrien; Fourt, Maïa; Pérez, Thierry; Chevaldonné, Pierre

    2017-02-21

    During the exploration of the NW Mediterranean deep-sea canyons (MedSeaCan and CorSeaCan cruises), several hexactinellid sponges were observed and collected by ROV and manned submersible. Two of them appeared to be new species of Farrea and Tretodictyum. The genus Farrea had so far been reported with doubt from the Mediterranean and was listed as "taxa inquirenda" for two undescribed species. We here provide a proper description for the specimens encountered and sampled. The genus Tretodictyum had been recorded several times in the Mediterranean and in the near Atlantic as T. tubulosum Schulze, 1866, again with doubt, since the type locality is the Japan Sea. We here confirm that the Mediterranean specimens are a distinct new species which we describe. We also provide18S rDNA sequences of the two new species and include them in a phylogenetic tree of related hexactinellids.

  19. Genetics Home Reference: familial Mediterranean fever

    MedlinePlus

    ... health and development? More about Mutations and Health Inheritance Pattern Familial Mediterranean fever is almost always inherited in ... in an autosomal dominant pattern . An autosomal dominant inheritance pattern describes cases in which one copy of the ...

  20. The Strategic Importance of the Mediterranean

    DTIC Science & Technology

    1990-03-26

    Mediterranean and the straits of Bosphorus. From ancient times, man has struggled to control thebe vital maritime waterways. This geographic analysis shows that...axis to Greece and Italy. From the American’s viewpoint, the sea joins the United * States Central Command (USCENTCOM) and the United States European...separated southern flank nations, Turkey and Greece . An American control over the Mediterranean accomplishes the following: o Maintains maritime control in an

  1. Towards the advancement of the Mediterranean food cultures.

    PubMed

    Dernini, Sandro

    2006-02-01

    The Forum on Mediterranean Food Cultures has the purpose to foster an interdisciplinary dialogue to acknowledge the underestimated role of the Mediterranean diet and of the Mediterranean food cultures for an effective sustainable development in the Mediterranean. It is addressed towards the achievement of food security and a broader nutritional well-being in the entire Mediterranean area. The Forum uses a creative approach for the development of community-based programmes to manage the emerging trend of childhood overweight and obesity, as well as to reduce the increasing erosion of the Mediterranean food cultural heritage.

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

    USGS Publications Warehouse

    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).

  3. 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

    USGS Publications Warehouse

    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.

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

    PubMed

    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.

  5. The maternal genes Ci-p53/p73-a and Ci-p53/p73-b regulate zygotic ZicL expression and notochord differentiation in Ciona intestinalis embryos.

    PubMed

    Noda, Takeshi

    2011-12-01

    I isolated a Ciona intestinalis homolog of p53, Ci-p53/p73-a, in a microarray screen of rapidly degraded maternal mRNA by comparing the transcriptomes of unfertilized eggs and 32-cell stage embryos. Higher expression of the gene in eggs and lower expression in later embryonic stages were confirmed by whole-mount in situ hybridization (WISH) and quantitative reverse transcription-PCR (qRT-PCR); expression was ubiquitous in eggs and early embryos. Knockdown of Ci-p53/p73-a by injection of antisense morpholino oligonucleotides (MOs) severely perturbed gastrulation cell movements and expression of notochord marker genes. A key regulator of notochord differentiation in Ciona embryos is Brachyury (Ci-Bra), which is directly activated by a zic-like gene (Ci-ZicL). The expression of Ci-ZicL and Ci-Bra in A-line notochord precursors was downregulated in Ci-p53/p73-a knockdown embryos. Maternal expression of Ci-p53/p73-b, a homolog of Ci-p53/p73-a, was also detected. In Ci-p53/p73-b knockdown embryos, gastrulation cell movements, expression of Ci-ZicL and Ci-Bra in A-line notochord precursors, and expression of notochord marker gene at later stages were perturbed. The upstream region of Ci-ZicL contains putative p53-binding sites. Cis-regulatory analysis of Ci-ZicL showed that these sites are involved in expression of Ci-ZicL in A-line notochord precursors at the 32-cell and early gastrula stages. These results suggest that p53 genes are maternal factors that play a crucial role in A-line notochord differentiation in C. intestinalis embryos by regulating Ci-ZicL expression.

  6. The Eratosthenes Seamount - Eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Ehrhardt, A.; Schnabel, M.; Damm, V.

    2012-04-01

    The Eratosthenes Seamount forms a prominent landmark in the Eastern Mediterranean. It is located south of Cyprus with the Levantine Basin on its eastern side, the Herodotus Basin on its western side and the Nile Cone south of the seamount. The Eratosthenes Seamount rises up to 750 m below sea surface and is about 1200 m higher than the surrounding seafloor of the Levantine Basin and the Nile Cone sediments. The Eratosthenes Seamount is considered as a continental fragment of the former African-Nubian Plate that was rifted to its present position relative to Africa during the formation of the Tethyan Ocean. In 2010 a detailed geophysical survey was carried out in the area of the Eratosthenes Seamount by the Federal Institute for Geosciences and Natural Resources of Germany including multichannel seismic (MCS), refraction seismics, magnetic, gravity and magnetotelluric data acquisition. First results show a highly deformed seamount, with a plateau-like top that is impacted by west-east trending graben formation. The slopes of the seamount are eroded showing deep incised ripple patterns and recent submarine landslides. The Eratosthenes Seamount produces also a prominent magnetic and gravity anomaly, both supporting its uniqueness in the area of the Eastern Mediterranean. Velocity information by refraction seismic modeling, as well as the models of the magnetic and gravity data show evidence for a volcanic core of the seamount with carbonate layers on top of the volcanic core. The slopes of the seamount terminate against a conspicuous rim-like escarpment that forms in addition the northern and western termination of the Messinian Evaporites in the study area. The MCS and refraction seismic data show a very deep Levantine Basin with maximum acoustic basement depths of 12 to 14 km very close to the slope of the Eratosthenes Seamount. The deepest sediments resolved by the MCS data are of Lower Cretaceous to Jurassic age. The refraction seismic model shows a 14 km thick

  7. Summer fire predictability in a Mediterranean environment

    NASA Astrophysics Data System (ADS)

    Marcos, Raül; Turco, Marco; Bedía, Joaquín; Llasat, Maria Carmen; Provenzale, Antonello

    2015-04-01

    Each year approximately 500000 hectares burn in Europe. Most of them are consequence of Mediterranean summer fires that lead to damages to the natural environment causing important economic and life losses. In order to allow the preparedness of adequate prevention measures in European Mediterranean regions, a better understanding of the summer fire predictability is crucial. Climate is a primary driver of the interannual variability of fires in Mediterranean-type ecosystems, controlling fuel flammability and fuel structure [1, 2]. That is, summer fires are linked to current-year climate values (proxies for the climatic factors that affect fuel flammability) and to antecedent climate variables (proxies for the climatic factors influencing fine fuel availability and connectivity). In our contribution we explore the long-term predictability of wildfires in a Mediterranean region (NE Spain), driving a multiple linear regression model with observed antecedent climate variables and with predicted variables from the ECMWF System-4 seasonal forecast. The approaches are evaluated through a leave-one-out cross-validation over the period 1983-2010. While the ECMWF System-4 proved of limited usefulness due to its limited skill, the model driven with antecedent climate variables alone allowed for satisfactory long-term prediction of above-normal fire activity, suggesting the feasibility of successful seasonal prediction of summer fires in Mediterranean-type regions. *References [1] M. Turco, M. C. Llasat, J. von Hardenberg, and A. Provenzale. Impact of climate variability on summer fires in a mediterranean environment (northeastern iberian peninsula). Climatic Change, 116:665-678, 2013. [2] M. Turco, M. C. Llasat, J. von Hardenberg, and A. Provenzale. Climate change impacts on wildfires in a Mediterranean environment. Climatic Change, 125: 369-380, 2014.

  8. Atlantic forcing of the Mediterranean oligotrophy

    NASA Astrophysics Data System (ADS)

    Huertas, I. E.; RíOs, A. F.; GarcíA-Lafuente, J.; Navarro, G.; Makaoui, A.; SáNchez-RomáN, A.; Rodriguez-Galvez, S.; Orbi, A.; RuíZ, J.; PéRez, F. F.

    2012-06-01

    The Mediterranean Sea shows a peculiar anomaly in its nutrient pattern compared to the global ocean, as there is decrease in nutrient concentration from west to east. This feature has been attributed to the antiestuarine circulation at the Strait of Gibraltar, where an eastward flow of Atlantic nutrient-poor surface waters is compensated by a westward countercurrent of Mediterranean nutrient-rich deep waters. This water exchange has been suggested as the ultimate cause for the oligotrophy of the Mediterranean basin, even though only a few studies have accurately examined the magnitude of the nutrient flux through the Strait of Gibraltar. In this work, data from the Gibraltar Fixed Time series (GIFT) between 2005 and 2008 were used to assess nutrient distributions. Applying a two-layer model of water mass exchange and using the Mediterranean outflow recorded in situ, the net export of nutrients from the Mediterranean to the Atlantic was calculated as 139 and 4.8 Gmol yr-1 of nitrate and phosphate, respectively. The results also demonstrated that the Atlantic inflow is not nutrient depleted and in particular contains significant levels of phosphate, which is the limiting factor for biological productivity in the eastern Mediterranean. The distribution of the quasi-conservative parameter N* in the western and eastern basins indicated that nitrate-deficient surface waters are transformed into phosphate-deficient bottom waters by internal cycling processes. Therefore, phosphate depletion in the Mediterranean does not have its origin in the entry of a phosphorus-impoverished Atlantic inflow through the Strait of Gibraltar.

  9. Myxozoan infections in Mediterranean mariculture.

    PubMed

    Palenzuela, O

    2006-06-01

    Fish mariculture has dramatically expanded in recent years in Mediterranean countries. In this scenario, several pathological problems have logically arisen and parasitological etiologies are increasingly being reported, either as primary or secondary pathogens. Myxozoa is the most diverse and economically important group of fish parasites, and several species are known to cause or contribute to losses in mariculture. Species of the genus Enteromyxum currently constitute the most serious parasitological threat. Some unusual biological characters, such as wide host spectrum and direct fish-to-fish transmission, together with high virulence for some host species, combine a dangerous cocktail which is emerging in recent years. Closed-system (recirculation) and heated-water locations are especially sensitive to chronic infections by these parasites, which can cause serious mortality and even discourage culture of some fish species at certain locations (i.e, Diplodus puntazzo). The presentation presents an overview of recent advances in research of marine myxozoans, focusing mainly in the most pathogenic, Enteromyxum spp. The incidence of these and other emerging infections, and the design of potential strategies for control will be introduced.

  10. Seasonality of Arctic Mediterranean Exchanges

    NASA Astrophysics Data System (ADS)

    Rieper, Christoph; Quadfasel, Detlef

    2015-04-01

    The Arctic Mediterranean communicates through a number of passages with the Atlantic and the Pacific Oceans. Most of the volume exchange happens at the Greenland-Scotland-Ridge: warm and saline Atlantic Water flows in at the surface, cold, dense Overflow Water flows back at the bottom and fresh and cold Polar Water flows out along the East Greenland coast. All surface inflows show a seasonal signal whereas only the outflow through the Faroe Bank Channel exhibits significant seasonality. Here we present a quantification of the seasonal cycle of the exchanges across the Greenland-Scotland ridge based on volume estimates of the in- and outflows within the last 20 years (ADCP and altimetry). Our approach is comparatistic: we compare different properties of the seasonal cycle like the strength or the phase between the different in- and outflows. On the seasonal time scale the in- and outflows across the Greenland-Scotland-Ridge are not balanced. The net flux thus has to be balanced by the other passages on the Canadian Archipelago, Bering Strait as well as runoff from land.

  11. [Sacroiliitis in familial Mediterranean fever].

    PubMed

    Connemann, B J; Steinhoff, J; Benstein, R; Sack, K

    1991-11-22

    A 15-year-old girl of Turkish descent had for one year complained of severe recurrent fever-associated deep back pains. Since she was three years of age she had suffered from repeated attacks of fever and severe abdominal pain which ceased spontaneously in 1-3 days. On physical examination the sacrum and iliosacral joints were very painful to percussion, and she limped. Radiography revealed symmetric destructive sacroiliitis. Despite the unusual location of the arthritis, the triad of fever, abdominal pain and arthritis, as well as her belonging to an ethnic "at risk" group, pointed to the diagnosis of familial mediterranean fever (FML) or recurrent hereditary polyserositis. This diagnosis was confirmed by a positive metaraminol provocation test in that infusion of metaraminol reproduced the typical pains. Collagen diseases, rheumatic disease, acute porphyria and chronic infectious processes were excluded. The sacroiliitis quickly responded to long-term administration of colchicine, 0.5 mg twice daily. The patient also has Hageman factor deficiency whose significance remains unclear.

  12. Woodlands Grazing Issues in Mediterranean Basin

    NASA Astrophysics Data System (ADS)

    Campos, P.

    2009-04-01

    In Mediterranean basin, woodlands grazing still continue to be important commercial owners' benefits. These owners manage woodlands vegetations as if they were not at risk of degradation and declining. Frequently, no temporally grazing set-aside is taken into account to avoid overgrazing of annual and perennial vegetations. Although less common, in the northern shore of Mediterranean basin undergrazing might increase the frequency and the number of catastrophic forest fires. This under/over grazing regime occurs in the Mediterranean basin woodlands with contrasted differences on land property rights, local economies and government livestock policy incentives. Spain and Tunisia are examples of these Mediterranean livestock contrasts. Most of Spanish Mediterranean woodlands and livestock herds are large private ownerships and owners could maintain their lands and livestock herds properties on the basis of moderate cash-income compensation against land revaluation and exclusive amenity self-consumption. The later is less tangible benefit and it could include family land legacy, nature enjoyment, country stile of life development, social status and so on. In public woodlands, social and environmental goals -as they are cultural heritage, biodiversity loss mitigation, soil conservation and employment- could maintain market unprofitable woodlands operations. Last three decades Spanish Mediterranean woodlands owners have increased the livestock herds incentivized by government subsidies. As result, grazing rent is pending on the level of European Union and Spanish government livestock subsidies. In this context, Spanish Mediterranean woodlands maintain a high extensive livestock stoking population, which economy could be called fragile and environmentally unsustainable because forest degradation and over/under grazing practices. Tunisian Mediterranean woodlands are state properties and livestock grazing is practice as a free private regimen. Livestock herds are small herd

  13. Mediterranean Diet Plus Olive Oil a Boost to Heart Health?

    MedlinePlus

    ... gov/news/fullstory_163557.html Mediterranean Diet Plus Olive Oil a Boost to Heart Health? It enhances ... HealthDay News) -- A Mediterranean diet high in virgin olive oil may boost the protective effects of "good" ...

  14. The features of a "Mediterranean" Bioethics.

    PubMed

    Leone, Salvino

    2012-11-01

    Even if somebody considers inappropriate any geographic adjective for Bioethics, nevertheless we think that there are some specific features of "Mediterranean" Bioethics that could distinguish it from a "Northern-European and Northern-American" one. First of all we must consider that medical ethics was born and grew in Mediterranean area. First by the thought of great Greek philosophers as Aristotle (that analyse what ethics is), then by Hippocrates, the "father" of medical ethics. The ethical pattern of Aristotle was based on "virtues" and their practice. In this perspective we can already note a strong difference with actual North-European or American principialist ethics. But a second consideration concerns the role that great Mediterranean religions (Judaism, Christianity and Islam) had in the construction of the ethical thought especially on the matter of life and its respect. So, in our pluralistic and multicultural society is absolutely necessary to rescue an approach that considers both "lungs" of ethical thought (Mediterranean and Northern one) and highlights the role that Mediterranean Ethics still has in this way.

  15. Mediterranean diet pyramids: towards the Italian model.

    PubMed

    del Balzo, V; Diolordi, L; Pinto, A; Giusti, A M; Vitiello, V; Cannella, C; Dernini, S; Donini, L M; Berry, E M

    2012-01-01

    There is a long history to the representation of the Mediterranean Diet Pyramid which may be seen as a form of cultural--culinary evolution as each country applies the foods best suited to its national diet. Different Mediterranean Diet pyramids have been designed for the population of Greece, Spain and Italy, tailored for their different food habits. These refer variously to portion sizes and frequency of consumption--daily, weekly and monthly and are not standardized. The 3rd CIISCAM Conference held in Parma, Italy was devoted to highlight the overall biodiversity and nutritional well being values and the sustainable benefits of the Mediterranean diet, recognised as one of the healthiest dietary pattern, and to reduce the rapid erosion of "lifestyle and food habits. It is necessary, therefore, to refer more to a Mediterranean Lifestyle of which diet is only a part. It should include physical and social activity, recreation and rest. It may be possible to construct a Mediterranean food lifestyle index both to assess such a holistic aspect and to correlate with improved morbidity & mortality.

  16. Climate Optimum rejuvenates the Mediterranean marine world.

    PubMed

    Por, Francis D

    2010-06-01

    The Mediterranean, a sea with an already eventful history, is again undergoing an extreme change. A combination of general warming of the Mediterranean Sea and contact with the Indopacific world through the Suez Canal has set the stage for massive changes in the biota that inhabit this sea. For over a century, tropical species of all taxa have been migrating back into the Mediterranean, suggesting a duplication or restoration of a mid-Pliocene Piacenzian or late Miocene Tortonian situation. Test cases are presented in three major taxa. It is not a serial invasion by individual rogue exotic and damaging species, as often wrongly assumed and asserted. Despite its unique biogeographic magnitude being recognized, an opportunity to study the progress of this phenomenon is being missed. This is because of the changed priorities in research, the acute taxonomic impediment and to the geopolitical difficulties in cooperation. Nonetheless, the limitations of the restoration process are defined and a careful future outlook is presented.

  17. Decreasing Fires in Mediterranean Europe.

    PubMed

    Turco, Marco; Bedia, Joaquín; Di Liberto, Fabrizio; Fiorucci, Paolo; von Hardenberg, Jost; Koutsias, Nikos; Llasat, Maria-Carmen; Xystrakis, Fotios; Provenzale, Antonello

    2016-01-01

    Forest fires are a serious environmental hazard in southern Europe. Quantitative assessment of recent trends in fire statistics is important for assessing the possible shifts induced by climate and other environmental/socioeconomic changes in this area. Here we analyse recent fire trends in Portugal, Spain, southern France, Italy and Greece, building on a homogenized fire database integrating official fire statistics provided by several national/EU agencies. During the period 1985-2011, the total annual burned area (BA) displayed a general decreasing trend, with the exception of Portugal, where a heterogeneous signal was found. Considering all countries globally, we found that BA decreased by about 3020 km2 over the 27-year-long study period (i.e. about -66% of the mean historical value). These results are consistent with those obtained on longer time scales when data were available, also yielding predominantly negative trends in Spain and France (1974-2011) and a mixed trend in Portugal (1980-2011). Similar overall results were found for the annual number of fires (NF), which globally decreased by about 12600 in the study period (about -59%), except for Spain where, excluding the provinces along the Mediterranean coast, an upward trend was found for the longer period. We argue that the negative trends can be explained, at least in part, by an increased effort in fire management and prevention after the big fires of the 1980's, while positive trends may be related to recent socioeconomic transformations leading to more hazardous landscape configurations, as well as to the observed warming of recent decades. We stress the importance of fire data homogenization prior to analysis, in order to alleviate spurious effects associated with non-stationarities in the data due to temporal variations in fire detection efforts.

  18. Decreasing Fires in Mediterranean Europe

    PubMed Central

    Turco, Marco; Bedia, Joaquín; Di Liberto, Fabrizio; Fiorucci, Paolo; von Hardenberg, Jost; Koutsias, Nikos; Llasat, Maria-Carmen; Xystrakis, Fotios; Provenzale, Antonello

    2016-01-01

    Forest fires are a serious environmental hazard in southern Europe. Quantitative assessment of recent trends in fire statistics is important for assessing the possible shifts induced by climate and other environmental/socioeconomic changes in this area. Here we analyse recent fire trends in Portugal, Spain, southern France, Italy and Greece, building on a homogenized fire database integrating official fire statistics provided by several national/EU agencies. During the period 1985-2011, the total annual burned area (BA) displayed a general decreasing trend, with the exception of Portugal, where a heterogeneous signal was found. Considering all countries globally, we found that BA decreased by about 3020 km2 over the 27-year-long study period (i.e. about -66% of the mean historical value). These results are consistent with those obtained on longer time scales when data were available, also yielding predominantly negative trends in Spain and France (1974-2011) and a mixed trend in Portugal (1980-2011). Similar overall results were found for the annual number of fires (NF), which globally decreased by about 12600 in the study period (about -59%), except for Spain where, excluding the provinces along the Mediterranean coast, an upward trend was found for the longer period. We argue that the negative trends can be explained, at least in part, by an increased effort in fire management and prevention after the big fires of the 1980’s, while positive trends may be related to recent socioeconomic transformations leading to more hazardous landscape configurations, as well as to the observed warming of recent decades. We stress the importance of fire data homogenization prior to analysis, in order to alleviate spurious effects associated with non-stationarities in the data due to temporal variations in fire detection efforts. PMID:26982584

  19. Dsp in Moroccan Mediterranean Sea.

    NASA Astrophysics Data System (ADS)

    Rachid, Fadel

    At sea temperate, there is usually a sole major floraison of the phytoplancton (in the spring) that exhausts the available stock of nutritious salt. This phenomenon is natural. It's more known under the name of "red tide or colored waters", it brings about a danger, with hazardous consequences on the wildlife water wildlife. The toxins emitted by certain seaweeds, of this phytoplancton, are transmitted through the trophic chain to man. Sometimes the contamination of these sea fruits provokes empoisoning to the consumers. Sometimes phytoplanctonics efflorescences do not present any significant coloring but can generate an increased liberation of toxins in sea water. The relative concentration of the one here then is detected in the shellfishes. These organisms concentrate the phocotoxines in their hepatopancreas. These are therefore bio potential indicators of the sea environment. We studied, in parallel, the variation of the characteristic abiotics of the Mediterranean sites previously choosen (physico-chimicals parameters and oceanographics parameters) and the variation of the relative toxicity of the bio indicators in every site. It in springs that the zones navies, subjected to important water provisions coming from a river, undergo several excessive floraisons during the spring and the summer, thanks to their continuous supplying in nutriments. We noted that the arrival new water masses. We draw from this that the coastal areas, due to the precipitations of the winter, translates itself at the level of the embouchure of the estuary Oued Laou by the maximum concentration of contained toxins in the shellfishes and that these waters were loaded with drifts of the olive waste, liquid loss abandoned to himself after extraction of the oil of the renowned olives of this region.

  20. Solar dimming/brightening in the Mediterranean

    NASA Astrophysics Data System (ADS)

    Kambezidis, Harry; Demetriou, Dora; Kaskaoutis, Dimitris; Nastos, Panagiotis

    2010-05-01

    Early analyses of solar radiation records have pointed to a widespread decline of surface solar radiation from the 1950s up to the 1980s in various parts of the world. This phenomenon was attributed to increasing air pollution and has been named "global dimming". More recent analyses with data records updated to near present suggested that surface solar radiation shows no sign of decrease anymore since the 1980s or even started to recover at many locations. This recovery has been named "solar brightening". Air pollution control and the economic breakdown of the former communist countries are the major influential factors for this transition. Further the influence of the recovery from the dimming caused by Mt. Pinatubo volcanic eruption in 1991 and internal climate variability with associated cloud variations were suggested to contribute to the brightening in the 1990s. Despite the interest in the solar dimming/brightening phenomenon the Mediterranean area has not attracted the attention of the scientists in this respect so far. Therefore, the present work tries to fill this gap by providing spatio-temporal analysis of the incoming short-wave solar radiation in the whole area of the Mediterranean Sea in the period 1979-2004 taken from satellites. To give better spatial information about the phenomenon the Mediterranean region has been divided into three sub-regions: the West Mediterranean, from Gibraltar to Corsica, the Central Mediterranean, from Corsica to the Ionian Sea, and the East Mediterranean, from the Ionian Sea to the shores of Syria. The analysis shows that the three sub-regions have not undergone the same spatio-temporal pattern of the phenomenon probably due to the different distribution of aerosols in the region.

  1. Severe Weather Guide, Mediterranean Ports. 20. Livorno

    DTIC Science & Technology

    1988-05-01

    SUBJECT TERMS (Continue on reverse if necessary and identify by block number) Storm haven Mediterranean meteorology Livorno port Mediterranean...Storrvi haven , Livorno iDort, i’ledi terranean meteorology, i^ie d 11 e r’ r’ a n e a n oc e a D O Q r a o !"i v H ( i e IS ) (U) 01 •Naval...Evaluation of the Harbor as a Haven . .3-5 3.3 Currents and Tides 3-6 3.4 Visibility 3-7 3.5 Hazardous Conditions 3-7 3.6 Harbor Protection 3-12

  2. Evidence by a voltage clamp study of an electrically mediated block to polyspermy in the egg of the ascidian Phallusia mammillata.

    PubMed

    Goudeau, H; Depresle, Y; Rosa, A; Goudeau, M

    1994-12-01

    Eggs of the ascidian Phallusia mammillata were voltage clamped (from -100 to +60 mV) and inseminated with a low or heavy sperm concentration. From inseminations with low sperm concentration (1 x 10(6) sp/ml), we found that fertilization currents occurred between -100 and +40 mV: they were always inward and displayed an analogous pattern whatever the clamped voltage. We established that the percentages of inseminated eggs that produced a fertilization current varied as a function of the clamped voltage. These percentages were not statistically different from 100% at clamped voltages between -100 and -30 mV, they decreased to 68 and 56% at clamped Vm of -10 and 0 mV, respectively, but were not statistically different from 0% at clamped Vm between +10 and +40 mV. We never obtained any egg electrical response at a clamped voltage of +50 mV. Almost all eggs (96%) which responded electrically were penetrated by one or several spermatozoa. These eggs were resuming meiosis (81 to 50%) at values of clamped Vm between -100 and 0 mV, respectively. At clamped Vm between +10 and +50 mV, the percentages of eggs resuming meiosis were not statistically different from 0. These results indicate that in P. mammillata eggs, the occurrence of an electrical response is voltage dependent and consequently that the initial depolarizing shift of the fertilization potential constitutes a fast block to polyspermy. However, in this species, the sperm penetration is not voltage dependent, since it occurred at clamped Vm from -100 to +40 mV. On the other hand, when eggs were clamped from -100 to +60 mV and inseminated with a heavy sperm concentration (2 x 10(7) sp/ml), the curves expressing, respectively, the percentages of eggs which responded electrically, the percentages of eggs which were penetrated by one or several spermatozoa, and the percentages of eggs resuming meiosis, as functions of the clamped Vm, were shifted by approximately 35 mV toward more positive voltages, compared to the

  3. Dust Shrouds the Eastern Mediterranean

    NASA Technical Reports Server (NTRS)

    2002-01-01

    On October 18, 2002, a large dust plume extended across countries bordering the eastern Mediterranean Sea. Information on the horizontal and vertical extent of the dust are provided by these views from the Multi-angle Imaging SpectroRadiometer (MISR). The left-hand panel portrays the scene as viewed by the instrument's vertical-viewing (nadir) camera. Here only some of the dust over eastern Syria and southeastern Turkey can be discerned. The dust is much more obvious in the center panel, which is a view from MISR's most steeply forward-looking camera. In addition, this perspective makes shadows cast by clouds onto the dust layer more apparent, providing a visual clue that the dust is at a lower altitude than these clouds.

    The right-hand panel is an elevation field derived from automated MISR stereoscopic processing, in which the heights of clouds and certain parts of the dust plume are retrieved. Because the stereoscopic approach makes use of features within the images that exhibit spatial contrast, heights for much of the dust plume (as well as the ocean surface) could not be retrieved, and these areas are shown in dark gray. Clouds within the image area are situated between about 2 and 5.5 kilometers above sea level, and the dust is located below most of the cloud, at heights of about 1.5 kilometers or less. When the stereo retrieval determines that a location is at a near-surface altitude, digital terrain elevation data are displayed instead. The highest clouds in this scene appear as the orange and red areas, and mountainous regions are displayed in light blue and green.

    The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously from pole to pole, and every 9 days views the entire globe between 82 degrees north and 82 degrees south latitude. These data products were generated from a portion of the imagery acquired during Terra orbit 15072. The panels cover an area of about 380 kilometers x 827 kilometers, and utilize data from

  4. Plastic accumulation in the Mediterranean sea.

    PubMed

    Cózar, Andrés; Sanz-Martín, Marina; Martí, Elisa; González-Gordillo, J Ignacio; Ubeda, Bárbara; Gálvez, José Á; Irigoien, Xabier; Duarte, Carlos M

    2015-01-01

    Concentrations of floating plastic were measured throughout the Mediterranean Sea to assess whether this basin can be regarded as a great accumulation region of plastic debris. We found that the average density of plastic (1 item per 4 m2), as well as its frequency of occurrence (100% of the sites sampled), are comparable to the accumulation zones described for the five subtropical ocean gyres. Plastic debris in the Mediterranean surface waters was dominated by millimeter-sized fragments, but showed a higher proportion of large plastic objects than that present in oceanic gyres, reflecting the closer connection with pollution sources. The accumulation of floating plastic in the Mediterranean Sea (between 1,000 and 3,000 tons) is likely related to the high human pressure together with the hydrodynamics of this semi-enclosed basin, with outflow mainly occurring through a deep water layer. Given the biological richness and concentration of economic activities in the Mediterranean Sea, the affects of plastic pollution on marine and human life are expected to be particularly frequent in this plastic accumulation region.

  5. Dolphin Morbillivirus Epizootic Resurgence, Mediterranean Sea

    PubMed Central

    Raga, Juan-Antonio; Domingo, Mariano; Corteyn, Mandy; Van Bressem, Marie-Françoise; Fernández, Mercedes; Aznar, Francisco-Javier; Barrett, Thomas

    2008-01-01

    In July 2007, >100 striped dolphins, Stenella coeruleoalba, were found dead along the coast of the Spanish Mediterranean. Of 10 dolphins tested, 7 were positive for a virus strain closely related to the dolphin morbillivirus that was isolated during a previous epizootic in 1990. PMID:18325265

  6. Plastic Accumulation in the Mediterranean Sea

    PubMed Central

    Cózar, Andrés; Sanz-Martín, Marina; Martí, Elisa; González-Gordillo, J. Ignacio; Ubeda, Bárbara; Gálvez, José Á.; Irigoien, Xabier; Duarte, Carlos M.

    2015-01-01

    Concentrations of floating plastic were measured throughout the Mediterranean Sea to assess whether this basin can be regarded as a great accumulation region of plastic debris. We found that the average density of plastic (1 item per 4 m2), as well as its frequency of occurrence (100% of the sites sampled), are comparable to the accumulation zones described for the five subtropical ocean gyres. Plastic debris in the Mediterranean surface waters was dominated by millimeter-sized fragments, but showed a higher proportion of large plastic objects than that present in oceanic gyres, reflecting the closer connection with pollution sources. The accumulation of floating plastic in the Mediterranean Sea (between 1,000 and 3,000 tons) is likely related to the high human pressure together with the hydrodynamics of this semi-enclosed basin, with outflow mainly occurring through a deep water layer. Given the biological richness and concentration of economic activities in the Mediterranean Sea, the affects of plastic pollution on marine and human life are expected to be particularly frequent in this plastic accumulation region. PMID:25831129

  7. Meteotsunami occurrence frequency along the Mediterranean coasts

    NASA Astrophysics Data System (ADS)

    Masina, Marinella; Archetti, Renata; Lamberti, Alberto

    2016-04-01

    A number of research studies describe exceptional destructive meteotsunami events since long time whereas no systematic database is available of moderate events because sea level data were recorded with insufficient resolution. Sea level measurements recently collected with high sampling rate, one per minute or less, by tide gauges positioned along the Mediterranean coasts are examined, aiming to analyze the occurrence of oscillation events in the tsunami frequency range. Sea level data from operating tide stations inside the Mediterranean basin are made publicly available through the Intergovernmental Oceanographic Commission Sea Level Monitoring Facility web site (http://www.ioc-sealevelmonitoring.org/). After the implementation of a rigorous quality check procedure to the raw water level time series, Hilbert transform is applied to two hour high-pass filtered observations to identify tsunami-like oscillation events. Events of seismic origin are identified by consistency between earthquake occurrence and tsunami wave travel time from the earthquake epicenter to the specific tide gauge. Similar analyses are performed to exclude sea waves induced harbor seiches events. A list of probable meteotsunami episodes occurred in the Mediterranean region is so compiled and their occurrence frequency and intensity statistics are evaluated at the different tide gauge sites over the time period of high frequency water level data availability ranging from five to seven years. The effects of atmospheric conditions and seabed topography are discussed. Detection and characterization of meteotsunamis, both of exceptional character and of weak intensity, represent an essential step toward improved assessments of coastal flooding risk along the Mediterranean coasts.

  8. Climatic Feedbacks and Desertification: The Mediterranean Model.

    NASA Astrophysics Data System (ADS)

    Millán, M. M.; Estrela, M. J.; Sanz, M. J.; Mantilla, E.; Martín, M.; Pastor, F.; Salvador, R.; Vallejo, R.; Alonso, L.; Gangoiti, G.; Ilardia, J. L.; Navazo, M.; Albizuri, A.; Artíñano, B.; Ciccioli, P.; Kallos, G.; Carvalho, R. A.; Andrés, D.; Hoff, A.; Werhahn, J.; Seufert, G.; Versino, B.

    2005-03-01

    Mesometeorological information obtained in several research projects in southern Europe has been used to analyze perceived changes in the western Mediterranean summer storm regime. A procedure was developed to disaggregate daily precipitation data into three main components: frontal precipitation, summer storms, and Mediterranean cyclogenesis. Working hypotheses were derived on the likely processes involved. The results indicate that the precipitation regime in this Mediterranean region is very sensitive to variations in surface airmass temperature and moisture. Land-use perturbations that accumulated over historical time and greatly accelerated in the last 30 yr may have induced changes from an open, monsoon-type regime with frequent summer storms over the mountains inland to one dominated by closed vertical recirculations where feedback mechanisms favor the loss of storms over the coastal mountains and additional heating of the sea surface temperature during summer. This, in turn, favors Mediterranean cyclogenesis and torrential rains in autumn-winter. Because these intense rains and floods can occur anywhere in the basin, perturbations to the hydrological cycle in any part of the basin can propagate to the whole basin and adjacent regions. Furthermore, present levels of air pollutants can produce greenhouse heating, amplifying the perturbations and pushing the system over critical threshold levels. The questions raised are relevant for the new European Union (EU) water policies in southern Europe and for other regions dominated by monsoon-type weather systems.

  9. Morbillivirus and Pilot Whale Deaths, Mediterranean Sea

    PubMed Central

    Esperón, Fernando; Herraéz, Pedro; de los Monteros, Antonio Espinosa; Clavel, Cristina; Bernabé, Antonio; Sánchez-Vizcaino, J. Manuel; Verborgh, Philippe; DeStephanis, Renaud; Toledano, Francisco; Bayón, Alejandro

    2008-01-01

    An outbreak of a lethal morbillivirus infection of long-finned pilot whales occurred in the Mediterranean Sea from the end of October 2006 through April 2007. Sequence analysis of a 426-bp conserved fragment of the morbillivirus phosphoprotein gene indicates that the virus is more closely related to dolphin morbillivirus than to pilot whale morbillivirus. PMID:18439363

  10. Mineral dust deposition in Western Mediterranean basin

    NASA Astrophysics Data System (ADS)

    Vincent, Julie; Laurent, Benoit; Bergmatti, Gilles; Losno, Rémi; Bon Nguyen, Elisabeth; Chevaillier, Servanne; Roulet, Pierre; Sauvage, Stéphane; Coddeville, Patrice; Ouboulmane, Noura; Siour, Guillaume; Tovar Sanchez, Antonio; Massanet, Ana; Morales Baquero, Rafael; Di Sarra, Giogio; Sferlazzo, Damiano; Dulac, François; Fornier, Michel; Coursier, Cyril

    2014-05-01

    North African deserts are the world's largest sources of atmospheric mineral dust produced by aeolian erosion. Saharan dust is frequently transported toward Europe over the Mediterranean basin. When deposited in oceanic areas, mineral dust can constitute a key input of nutrients bioavailable for the oceanic biosphere. For instance, Saharan dust deposited in the in the Mediterranean Sea can be a significant source of nutrient like Fe, P and N during summer and autumn. Our objective is to study the deposition Saharan mineral dust in the western Mediterranean basin and to improve how deposition processes are parameterized in 3D regional models. To quantify the deposition flux of Saharan dust in the western Mediterranean region a specific collector (CARAGA) to sample automatically the insoluble atmospheric particle deposition was developed (LISA-ICARE) and a network of CARAGA collectors have been set up. Since 2011, eight CARAGA are then deployed in Frioul, Casset, Montandon and Ersa in France, Mallorca and Granada in Spain, Lampedusa in Italia, and Medenine in Tunisia, along a South-North gradient of almost 2000km from the North African coast to the South of Europe. We observe 10 well identified dust Saharan deposition events at Lampedusa and 6 at Mallorca for a 1-yr sampling period. These dust events are sporadic and the South-North gradient of deposition intensity and frequency is observed (the highest dust mass sampled at the stations are : 2,66 g.m-2 at Lampedusa ; 0,54 g.m-2 at Majorque ; 0,33 g.m-2 at Frioul ; 0,16 g.m-2 at Casset). The ability of the CHIMERE model to reproduce the deposition measurements is tested. The mineral dust plumes simulated over the western Mediterranean basin are also compared to satellite observations (OMI, MODIS) and in-situ measurements performed during the ChArMEx campaign and in the AERONET stations.

  11. Erosion and Land Degradation in Mediterranean areas as a adaptive response to Mediterranean agriiculture

    NASA Astrophysics Data System (ADS)

    Imeson, Anton

    2014-05-01

    The motivation for this session is the statement or claim that Mediterranean areas are sensitive to erosion and desertification. One result of the LEDDRA Approach, which is applying the Complex Adaptive (CAS)paradigm at study sites in Mediterranean Spain, Greece and Italy is that there is just a single socio-environmental system in which land degradation is being caused by the actions of people and the Mediterranean soils have co-eveolved with people under the influence of fire and grazing. They are therefore resilient, and this was demonstrated by Naveh and Thornes. Also the Medalus field sites showed very low rates of erosion. With examples from different Mediterranean landscapes, it is considered that Mediterranean landscapes went through an initial phase of being sensitive to erosion which ended up with the original soils before ploughing or deforestation, being eroded from most of the areas, In some places these are found. LEDDRA The Leddra approach is to consider different states which are separated by transitions. The first state is that of the deforestaion and destruction of the forest that took place 6000 10000 years ago, in the Eastern and Northern Mediterranean, and 2000 to 4,000 years ago in large areas of the Western Mediterranean, and 100 to 400 years ago in California. Australia, New Zealand and Chile. The second state involves appropriating and settling the land from indigenous people and introducing cattle and sheep and Mediterranean crops. The current state of desertification is one in which erosion occurs because of the use of specific cultivation methods and subsidies for irrigating and producing crops outside of their range. In the Mediterranean landscape State, such as found near Santiago in Chile and in Crete, society gains many cultural benefits from grazing. However, the consequences of this are that the whole ecosystem is maintained in an arid state, so that areas in Crete receiving 800-1100 mm rainfall have a semi arid vegetation, instead

  12. 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.

    PubMed

    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.

  13. Transcription regulatory mechanism of Pitx in the papilla-forming region in the ascidian, Halocynthia roretzi, implies conserved involvement of Otx as the upstream gene in the adhesive organ development of chordates.

    PubMed

    Yoshida, Keita; Ueno, Motoko; Niwano, Tomoko; Saiga, Hidetoshi

    2012-08-01

    Pitx genes play important roles in a variety of developmental processes in vertebrates. In an ascidian species, Halocynthia roretzi, Hr-Pitx, the only Pitx gene of this species, has been reported to be expressed in the left epidermis at the tailbud stage. In the present study, first, we have shown that Hr-Pitx is also expressed in the papilla-forming region at the neurula to tailbud stages, and then we addressed transcription regulatory mechanisms for the expression of Hr-Pitx in the papilla-forming region. We have identified the genomic region ranging from 850 to 1211 bp upstream from the translation start site of the Hr-Pitx gene as an enhancer region that drives the transcription of Hr-Pitx in the papilla-forming region. Within the enhancer region, putative transcriptional factor binding sites for Otx as well as Fox were shown to be required for its activity. Finally, we carried out knocking down experiments of Hr-Otx function using an antisense morpholino oligonucleotide, in which the knocking down of Hr-Otx function resulted in reduction of the enhancer activity and loss of the expression of Hr-Pitx in the papilla-forming region. In Xenopus laevis, it has been reported that Pitx genes are expressed downstream of Otx function during development of the cement gland, an adhesive organ of its larva. Taken together, it is suggested that the expression regulatory mechanism of Pitx, involving Otx as the upstream gene, in the developing adhesive organ is conserved between ascidians and vertebrates.

  14. Hydrometeorological extremes in the Mediterranean area

    NASA Astrophysics Data System (ADS)

    Llasat, M. C.; Rigo, T.

    2003-04-01

    Between the 9th and 18th of November of 2001, a succession of hydrometeorological hazards affected the West of the Mediterranean area. High rainfalls above 200mm /24 h gave place to catastrophic floods in Algeria, Balearic Islands, Morocco and the Northeast of the Iberian Peninsula; extreme winds of more than 30 m/s of sustained speed uprooted thousands of trees, removed up to 50 per cent of the sand in a great number of beaches of the Balearic Islands and Catalonia and made waves over 11 m high; combined with the wind, the hail destroyed the crops in the littoral region of Catalonia, whereas a cold wave affected the rest of Spain, with the snow arriving to Catalonia. Over 600 people died in Algeria and up to 10 in Spain, with material damage up to 150M euros. In this case a strong cyclone was identified as one of the main causes of the severe weather produced. A study developed into the framework of the MEDEX project shows that the Gulf of Genoa (mainly medium and deep cyclones) and the Iberian Peninsula (mainly shallow cyclones) are the most cyclogenesis prone areas in the West Mediterranean (Campins et al, 2002). Although the West part of the Mediterranean shows the maximum number of cyclones, it is also important in the Eastern part (smoothed values are, respectively, 437 and 353, following the results of Gil et al, 2002). Although the events of November 2001 are not usual in the Mediterranean area, hydrometeorological hazards that affect more than one country (usually Spain, France and Italy) are frequent. But not all the catastrophic events are so vast. On the 25th of September of 1962 a catastrophic flash-flood produced 815 casualties in less than 150 km2 and on the 10th of June of 2000, more than 200 mm were recorded in less than 3 hours. Although the Mediterranean climate is identified with dry summers, that season shows the greatest rate of convective events (Llasat, 2001) that can lead to flash floods in little catchments, usually in mountain and coastal

  15. Benefits of the Mediterranean diet beyond the Mediterranean Sea and beyond food patterns.

    PubMed

    Martínez-González, Miguel A

    2016-10-14

    Abundant and growing evidence has accrued to demonstrate that the traditional Mediterranean diet is likely to be the ideal dietary pattern for the prevention of cardiovascular disease. A landmark randomized trial (PREDIMED) together with many well-conducted long-term observational prospective cohort studies support this causal effect.A new, large British cohort study by Tong et al. assessing the association between adherence to the Mediterranean diet and cardiovascular disease was recently published in BMC Medicine. Using a superb methodology, they followed-up 23,902 participants for 12.2 years on average and observed several thousand incident cases.The results of this cohort study showed a significant beneficial effect of the Mediterranean diet on cardiovascular events. These findings support the transferability of this dietary pattern beyond the shores of the Mediterranean Sea. The authors provided measures of population impact in cardiovascular prevention and estimated that 19,375 cases of cardiovascular death would be prevented each year in the UK by promoting the Mediterranean Diet.Please see related article: http://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-016-0677-4 .

  16. Food Processing and the Mediterranean Diet

    PubMed Central

    Hoffman, Richard; Gerber, Mariette

    2015-01-01

    The benefits of the Mediterranean diet (MD) for protecting against chronic disorders such as cardiovascular disease are usually attributed to high consumption of certain food groups such as vegetables, and low consumption of other food groups such as meat. The influence of food processing techniques such as food preparation and cooking on the nutrient composition and nutritional value of these foods is not generally taken into consideration. In this narrative review, we consider the mechanistic and epidemiological evidence that food processing influences phytochemicals in selected food groups in the MD (olives, olive oil, vegetables and nuts), and that this influences the protective effects of these foods against chronic diseases associated with inflammation. We also examine how the pro-inflammatory properties of meat consumption can be modified by Mediterranean cuisine. We conclude by discussing whether food processing should be given greater consideration, both when recommending a MD to the consumer and when evaluating its health properties. PMID:26393643

  17. Early Spring Dust over the Mediterranean Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Sea-viewing Wide Field-of-view Sensor (SeaWiFS) observed this large cloud of dust (brownish pixels) blowing from northern Africa across the Mediterranean Sea on March 4, 2002. The dust can be seen clearly blowing across Southern Italy, Albania, Greece, and Turkey-all along the Mediterranean's northeastern shoreline. Notice that there also appears to be human-made aerosol pollution (greyish pixels) pooling in the air just south of the Italian Alps and blowing southeastward over the Adriatic Sea. The Alps can be easily identified as the crescent-shaped, snow-capped mountain range in the top center of this true-color scene. There also appears to be a similar haze over Austria, Hungary, and Yugoslavia to the north and east of Italy. Image courtesy the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  18. Food Processing and the Mediterranean Diet.

    PubMed

    Hoffman, Richard; Gerber, Mariette

    2015-09-17

    The benefits of the Mediterranean diet (MD) for protecting against chronic disorders such as cardiovascular disease are usually attributed to high consumption of certain food groups such as vegetables, and low consumption of other food groups such as meat. The influence of food processing techniques such as food preparation and cooking on the nutrient composition and nutritional value of these foods is not generally taken into consideration. In this narrative review, we consider the mechanistic and epidemiological evidence that food processing influences phytochemicals in selected food groups in the MD (olives, olive oil, vegetables and nuts), and that this influences the protective effects of these foods against chronic diseases associated with inflammation. We also examine how the pro-inflammatory properties of meat consumption can be modified by Mediterranean cuisine. We conclude by discussing whether food processing should be given greater consideration, both when recommending a MD to the consumer and when evaluating its health properties.

  19. Major tomato viruses in the Mediterranean basin.

    PubMed

    Hanssen, Inge M; Lapidot, Moshe

    2012-01-01

    Tomato (Solanum lycopersicum L.) originated in South America and was brought to Europe by the Spaniards in the sixteenth century following their colonization of Mexico. From Europe, tomato was introduced to North America in the eighteenth century. Tomato plants show a wide climatic tolerance and are grown in both tropical and temperate regions around the world. The climatic conditions in the Mediterranean basin favor tomato cultivation, where it is traditionally produced as an open-field plant. However, viral diseases are responsible for heavy yield losses and are one of the reasons that tomato production has shifted to greenhouses. The major tomato viruses endemic to the Mediterranean basin are described in this chapter. These viruses include Tomato yellow leaf curl virus, Tomato torrado virus, Tomato spotted wilt virus, Tomato infectious chlorosis virus, Tomato chlorosis virus, Pepino mosaic virus, and a few minor viruses as well.

  20. Sediment transport in two mediterranean regulated rivers.

    PubMed

    Lobera, G; Batalla, R J; Vericat, D; López-Tarazón, J A; Tena, A

    2016-01-01

    Mediterranean climate is characterized by highly irregular rainfall patterns with marked differences between wet and dry seasons which lead to highly variable hydrological fluvial regimes. As a result, and in order to ensure water availability and reduce its temporal variability, a high number of large dams were built during the 20th century (more than 3500 located in Mediterranean rivers). Dams modify the flow regime but also interrupt the continuity of sediment transfer along the river network, thereby changing its functioning as an ecosystem. Within this context, the present paper aims to assess the suspended sediment loads and dynamics of two climatically contrasting Mediterranean regulated rivers (i.e. the Ésera and Siurana) during a 2-yr period. Key findings indicate that floods were responsible for 92% of the total suspended sediment load in the River Siurana, while this percentage falls to 70% for the Ésera, indicating the importance of baseflows on sediment transport in this river. This fact is related to the high sediment availability, with the Ésera acting as a non-supply-limited catchment due to the high productivity of the sources (i.e. badlands). In contrast, the Siurana can be considered a supply-limited system due to its low geomorphic activity and reduced sediment availability, with suspended sediment concentration remaining low even for high magnitude flood events. Reservoirs in both rivers reduce sediment load up to 90%, although total runoff is only reduced in the case of the River Ésera. A remarkable fact is the change of the hydrological character of the River Ésera downstream for the dam, shifting from a humid mountainous river regime to a quasi-invariable pattern, whereas the Siurana experiences the opposite effect, changing from a flashy Mediterranean river to a more constant flow regime below the dam.

  1. The alarming decline of Mediterranean fish stocks.

    PubMed

    Vasilakopoulos, Paraskevas; Maravelias, Christos D; Tserpes, George

    2014-07-21

    In recent years, fisheries management has succeeded in stabilizing and even improving the state of many global fisheries resources [1-5]. This is particularly evident in areas where stocks are exploited in compliance with scientific advice and strong institutional structures are in place [1, 5]. In Europe, the well-managed northeast (NE) Atlantic fish stocks have been recovering in response to decreasing fishing pressure over the past decade [3-6], albeit with a long way to go for a universal stock rebuild [3, 7]. Meanwhile, little is known about the temporal development of the European Mediterranean stocks, whose management relies on input controls that are often poorly enforced. Here, we perform a meta-analysis of 42 European Mediterranean stocks of nine species in 1990-2010, showing that exploitation rate has been steadily increasing, selectivity (proportional exploitation of juveniles) has been deteriorating, and stocks have been shrinking. We implement species-specific simulation models to quantify changes in exploitation rate and selectivity that would maximize long-term yields and halt stock depletion. We show that stocks would be more resilient to fishing and produce higher long-term yields if harvested a few years after maturation because current selectivity is far from optimal, especially for demersal stocks. The European Common Fisheries Policy that has assisted in improving the state of NE Atlantic fish stocks in the past 10 years has failed to deliver similar results for Mediterranean stocks managed under the same policy. Limiting juvenile exploitation, advancing management plans, and strengthening compliance, control, and enforcement could promote fisheries sustainability in the Mediterranean.

  2. box modeling of the eastern mediterranean sea

    NASA Astrophysics Data System (ADS)

    Ashkenazy, Y.; Stone, P. H.

    2003-04-01

    Recently (~1990) a new source of deep water formation in the Eastern Mediterranean was found in the southern part of the Aegean sea. Till then, the only source of deep water formation in the Eastern Mediterranean was in the Adriatic sea; the rate of the deep water formation of the new Aegean source is 1Sv=10^6m^3/s, three times larger then the Adriatic source. We develop a simple 3 box-model to study the stability of the thermohaline circulation of the Eastern Mediterranean sea. The 3 boxes represent the Adriatic sea, Aegean sea, and the Ionian sea. The boxes exchange heat and salinity and may be described by a set of nonlinear differential equations. We analytically analyze these equations and find that the system may have one, two, or four stable flux states. We consider two cases for which the temperatures of the boxes are (i) fixed or (ii) variable. After setting the parameters to correspond to the Eastern Mediterranean we find that the system has two stable states, one with (i) two thermally dominant sources of deep water formation in the Adriatic and Aegean and the other with (ii) a salinity dominant source of deep water formation in the Adriatic and a thermally dominant source in the Aegean. While the Adriatic thermally dominant source is comparable to the observed flux of 0.3Sv the Aegean source has much smaller flux than the observed value. This situation is analogous to the state of the thermohaline circulation pre 1990 where the only source of deep water formation was in the Adriatic. If we decrease the atmospheric temperature of the Aegean box by 2C in accordance with recent observations, we find that the deep water formation of the Aegean increases significantly to a value comparable to the recently observed flux.

  3. Detecting slab structure beneath the Mediterranean

    NASA Astrophysics Data System (ADS)

    Miller, Meghan S.; Sun, Daoyuan; Piana Agostinetti, Nicola

    2013-04-01

    The presence of subducted slabs in the Mediterranean has been well documented with seismic tomography, however, these images, which are produced by smoothed, damped inversions, underestimate the sharpness of the structures. The position and extent of the slabs and the presence possible tears or gaps in the subducted lithosphere are still debated, yet the shape and location these structures are important for kinematic reconstructions and evolution of the entire subduction zone system. Extensive distribution of broadband seismic instrumentation in the Mediterranean (Italian National Seismic Network in Italy and the NSF-PICASSO project in Spain and Morocco) has allowed us to use alternative methodologies to detect the position of the slabs and slab tears beneath the Central and Western Mediterranean. Using S receiver functions we are able to identify S-to-p conversions from the bottom of the subducted slab and a lack of these signals where there are gaps or tears in the slab. We also analyze broadband waveforms for changes in P wave coda from deep (> 300 km depth) local earthquakes. The waveform records for stations in southern Italy and around the Betic-Rif show large amplitude, high frequency (f > 5 Hz) late arrivals with long coda after relatively low-frequency onset. High frequency arrivals are the strongest from events whose raypaths travel within the slab to the stations where they are recorded allowing for mapping of where the subducted material is located within the upper mantle. These two methods, along with inferring the slab position from fast P-wave velocity perturbations in tomography and intermediate depth seismicity, provide additional geophysical evidence to aid in interpretation of the complex, segmented slab structure beneath the Mediterranean.

  4. Toxicity of Mediterranean Scyphomedusae: An Overview.

    PubMed

    Negro, Paola Del; Saul, Ciriaco; Bruno, Cataletto; Maria, Delogu G; Franco, Kokelj

    2016-01-01

    Following in-depth analysis and examination, jellyfish toxins have been found to consist of a mixture of proteins, carbohydrates, and other non-proteinaceous components. What remains to be clarified is the specific chemical nature of jellyfish toxins due to their heat lability. This paper reviews current knowledge of the toxic properties of the most common Mediterranean scyphozoans (A. aurita, C. hysoscella, C. tuberculata, P. noctiluca, R. pulmo) and the activity of their venom.

  5. Women and epilepsy in the Mediterranean cultures.

    PubMed

    Vanzan Paladin, A

    1997-08-01

    Women and epilepsy have been sharing many prejudices since the beginning of human history. Epileptic seizures have been often mistaken for hysteria and hysteria is mainly a disease of women: in the past, the physicians even proclaimed the existence of a form of epilepsy originated from the uterus. This paper briefly examines the relation women-epilepsy in the Mediterranean cultures through historical and literary examples.

  6. Environmentally driven synchronies of Mediterranean cephalopod populations

    NASA Astrophysics Data System (ADS)

    Keller, Stefanie; Quetglas, Antoni; Puerta, Patricia; Bitetto, Isabella; Casciaro, Loredana; Cuccu, Danila; Esteban, Antonio; Garcia, Cristina; Garofalo, Germana; Guijarro, Beatriz; Josephides, Marios; Jadaud, Angelique; Lefkaditou, Evgenia; Maiorano, Porzia; Manfredi, Chiara; Marceta, Bojan; Micallef, Reno; Peristeraki, Panagiota; Relini, Giulio; Sartor, Paolo; Spedicato, Maria Teresa; Tserpes, George; Hidalgo, Manuel

    2017-03-01

    The Mediterranean Sea is characterized by large scale gradients of temperature, productivity and salinity, in addition to pronounced mesoscale differences. Such a heterogeneous system is expected to shape the population dynamics of marine species. On the other hand, prevailing environmental and climatic conditions at whole basin scale may force spatially distant populations to fluctuate in synchrony. Cephalopods are excellent case studies to test these hypotheses owing to their high sensitivity to environmental conditions. Data of two cephalopod species with contrasting life histories (benthic octopus vs nectobenthic squid), obtained from scientific surveys carried out throughout the Mediterranean during the last 20 years were analyzed. The objectives of this study and the methods used to achieve them (in parentheses) were: (i) to investigate synchronies in spatially separated populations (decorrelation analysis); (ii) detect underlying common abundance trends over distant regions (dynamic factor analysis, DFA); and (iii) analyse putative influences of key environmental drivers such as productivity and sea surface temperature on the population dynamics at regional scale (general linear models, GLM). In accordance with their contrasting spatial mobility, the distance from where synchrony could no longer be detected (decorrelation scale) was higher in squid than in octopus (349 vs 217 km); for comparison, the maximum distance between locations was 2620 km. The DFA revealed a general increasing trend in the abundance of both species in most areas, which agrees with the already reported worldwide proliferation of cephalopods. DFA results also showed that population dynamics are more similar in the eastern than in the western Mediterranean basin. According to the GLM models, cephalopod populations were negatively affected by productivity, which would be explained by an increase of competition and predation by fishes. While warmer years coincided with declining octopus

  7. Severe Weather Guide Mediterranean Ports - 32. Taranto

    DTIC Science & Technology

    1990-11-01

    Swell and seas out of phase in outer harbor, cause great disturbance to ships, boating generally cancelled. * Anomalous radar and radio propagation...southeasterly winds, visibility near zero for a few hours during morning likely a couple times per year in May early June. * Anomalous radar and radio ...in the northern Mediterranean. Extremely anomalous radar and radio propagations are likely because of the strong low level inversion over the water

  8. The Mediterranean Diet: A History of Health

    PubMed Central

    ALTOMARE, Roberta; CACCIABAUDO, Francesco; DAMIANO, Giuseppe; PALUMBO, Vincenzo Davide; GIOVIALE, Maria Concetta; BELLAVIA, Maurizio; TOMASELLO, Giovanni; LO MONTE, Attilio Ignazio

    2013-01-01

    The Mediterranean tradition offers a cousine rich in colors, aromas and memories, which support the taste and the spirit of those who live in harmony with nature. Everyone is talking about the Mediterranean diet, but few are those who do it properly, thus generating a lot of confusion in the reader. And so for some it coincides with the pizza, others identified it with the noodles with meat sauce, in a mixture of pseudo historical traditions and folklore that do not help to solve the question that is at the basis of any diet: combine and balance the food so as to satisfy the qualitative and quantitative needs of an individual and in a sense, preserves his health through the use of substances that help the body to perform normal vital functions. The purpose of our work is to demonstrate that the combination of taste and health is a goal that can be absolutely carried out by everybody, despite those who believe that only a generous caloric intake can guarantee the goodness of a dish and the satisfaction of the consumers. That should not be an absolute novelty, since the sound traditions of the Mediterranean cuisine we have used for some time in a wide variety of tasty gastronomic choices, from inviting colors and strong scents and absolutely in line with health. PMID:23802101

  9. The mediterranean diet: a history of health.

    PubMed

    Altomare, Roberta; Cacciabaudo, Francesco; Damiano, Giuseppe; Palumbo, Vincenzo Davide; Gioviale, Maria Concetta; Bellavia, Maurizio; Tomasello, Giovanni; Lo Monte, Attilio Ignazio

    2013-01-01

    The Mediterranean tradition offers a cousine rich in colors, aromas and memories, which support the taste and the spirit of those who live in harmony with nature. Everyone is talking about the Mediterranean diet, but few are those who do it properly, thus generating a lot of confusion in the reader. And so for some it coincides with the pizza, others identified it with the noodles with meat sauce, in a mixture of pseudo historical traditions and folklore that do not help to solve the question that is at the basis of any diet: combine and balance the food so as to satisfy the qualitative and quantitative needs of an individual and in a sense, preserves his health through the use of substances that help the body to perform normal vital functions. The purpose of our work is to demonstrate that the combination of taste and health is a goal that can be absolutely carried out by everybody, despite those who believe that only a generous caloric intake can guarantee the goodness of a dish and the satisfaction of the consumers. That should not be an absolute novelty, since the sound traditions of the Mediterranean cuisine we have used for some time in a wide variety of tasty gastronomic choices, from inviting colors and strong scents and absolutely in line with health.

  10. Bioethics in Mediterranean culture: the Spanish experience.

    PubMed

    Busquets, Ester; Roman, Begoña; Terribas, Núria

    2012-11-01

    This article presents a view of bioethics in the Spanish context. We may identify several features common to Mediterranean countries because of their relatively similar social organisation. Each country has its own distinguishing features but we would point two aspects which are of particular interest: the Mediterranean view of autonomy and the importance of Catholicism in Mediterranean culture. The Spanish experience on bioethics field has been marked by these elements, trying to build a civic ethics alternative, with the law as an important support. So, Spanish bioethics has been developed in two parallel levels: in the academic and policy maker field (University and Parliament) and in clinical practice (hospitals and healthcare ethics committees), with different paces and methods. One of the most important changes in the paternalistic mentality has been promoted through the recognition by law of the patient's rights and also through the new generation of citizens, clearly aware on the exercise of autonomy. Now, the healthcare professionals have a new challenge: adapt their practice to this new paradigm.

  11. Adaptive Radiation in Mediterranean Cistus (Cistaceae)

    PubMed Central

    Guzmán, Beatriz; Lledó, María Dolores; Vargas, Pablo

    2009-01-01

    Background Adaptive radiation in Mediterranean plants is poorly understood. The white-flowered Cistus lineage consists of 12 species primarily distributed in Mediterranean habitats and is herein subject to analysis. Methodology/Principal Findings We conducted a “total evidence” analysis combining nuclear (ncpGS, ITS) and plastid (trnL-trnF, trnK-matK, trnS-trnG, rbcL) DNA sequences and using MP and BI to test the hypothesis of radiation as suggested by previous phylogenetic results. One of the five well-supported lineages of the Cistus-Halimium complex, the white-flowered Cistus lineage, comprises the higher number of species (12) and is monophyletic. Molecular dating estimates a Mid Pleistocene (1.04±0.25 Ma) diversification of the white-flowered lineage into two groups (C. clusii and C. salviifolius lineages), which display asymmetric characteristics: number of species (2 vs. 10), leaf morphologies (linear vs. linear to ovate), floral characteristics (small, three-sepalled vs. small to large, three- or five-sepalled flowers) and ecological attributes (low-land vs. low-land to mountain environments). A positive phenotype-environment correlation has been detected by historical reconstructions of morphological traits (leaf shape, leaf labdanum content and leaf pubescence). Ecological evidence indicates that modifications of leaf shape and size, coupled with differences in labdanum secretion and pubescence density, appear to be related to success of new species in different Mediterranean habitats. Conclusions/Significance The observation that radiation in the Cistus salviifolius lineage has been accompanied by the emergence of divergent leaf traits (such as shape, pubescence and labdanum secretion) in different environments suggets that radiation in the group has been adaptive. Here we argued that the diverse ecological conditions of Mediterranean habitats played a key role in directing the evolution of alternative leaf strategies in this plant group. Key

  12. Droughts and forest fires in Mediterranean Europe

    NASA Astrophysics Data System (ADS)

    Turco, Marco; Llasat, Maria-Carmen; von Hardenberg, Jost; Provenzale, Antonello

    2015-04-01

    Most of the total burned area in Europe occurs in Mediterranean regions, with severe economic and environmental damage, life loss and an average of about 4500 km2 burned every year. A better understanding of the impacts on wildfires of environmental and socioeconomic changes is crucial to develop adequate measures of prevention, adaptation and mitigation in this area. Here we focus on the impact of droughts on fires in European Mediterranean regions (Portugal, Spain, the south of France, Italy, Greece). This goal will be achieved through three specific supporting objectives: (1) Understanding past changes in fires in this region (extending the study of [1]); (2) Comparing and analyzing different drought indices (e.g. SPI, SPEI and SSI; see [2, 3] for more details on those indices); (3) Modeling the interaction between drought and fires (following and extending the study of [4]). We develop relatively simple regression models that link the fire activity to the key climate drivers. These models could be used to estimate fire responses to different climate change projections and environmental and socioeconomic scenarios ([5]). *References [1] Turco M., Llasat M. C., Tudela A., Castro X., and Provenzale A. Brief communication Decreasing fires in a Mediterranean region (1970-2010, NE Spain). Natural Hazards and Earth System Science, 13(3):649-652, 2013. [2] Zengchao H., AghaKouchak A., Nakhjiri N., and Farahmand A. Global Integrated Drought Monitoring and Prediction System. Scientific Data, 1:1-10, 2014. [3] Vicente-Serrano, S. M., Beguería, S. and López-Moreno, J. I. A multiscalar drought index sensitive to global warming: The standardized precipitation evapotranspiration index. Journal of Climate, 23:1696-1718, 2010. [4] Turco M., Llasat M. C., von Hardenberg J., and Provenzale A. Impact of climate variability on summer fires in a Mediterranean environment (northeastern Iberian Peninsula). Climatic Change, 116:665-678, 2013. [5] Turco M., Llasat M. C., von

  13. The chaotic properties of western mediterranean climate

    NASA Astrophysics Data System (ADS)

    Pérez-Lluch, M.; Pascual-Aguilar, J. A.; Andreu, V.

    2009-04-01

    The behaviour of rainfall in the Mediterranean region has been target of multiple studies because of its social economic and environmental implications. Mediterranean rainfalls are characterized by great variability between years combined whit recurrent drought periods and highly intense rain events. These circumstances favour the intensification of erosion processes and the incidence of landslides, floods, etc. Western Mediterranean zones show these facts more acute, which could become more critical in a near future according to climate change scenarios. Within such environments, see facing lands of Spain present most contrasting rainfall regimes within the western Mediterranean climates. Under such conditions, it is of paramount importance to determine rainfall behaviour according not only to general climate trends but also to specific microscale, or local, conditions -such as topograpy- that could be reflected in a random behaviour of rainfall. The objective of this work is to establish rainfall characteristics due to local topographic conditions according to the possible existence of chaotic dynamics. The methodology applies the correlation dimension method to analyse the presence of chaotic dynamics to rainfall time serie. This technique allows calculating the necessary variables to explain the rain behaviour and to establish suitable models that assume their complexity. The methodology have been applied to two monthly rainfall series (1950-1990) belonging to neighbouring stations with different topographic locations. Both rainfall stations, Elche and Novelda, are located in Alicante, eastern Spain, along the littoral mountain system. Elche with a SE orientation has a major marine influence, while Novelda, with a NW orientation, presents different local conditions with less Mediterranean sea influences. Results show a chaotic trend of low dimensionality in the two series analysed, having a clear saturation of correlation exponent for Elche rainfall records

  14. Eutrophication and environmental policy in the Mediterranean Sea: a review.

    PubMed

    Karydis, Michael; Kitsiou, Dimitra

    2012-08-01

    The Mediterranean Sea is a semienclosed basin connected with the open sea mainly through the Strait of Gibraltar. Due to the circulation pattern and the long residence time ranging between 80 and 100 years, the Mediterranean Sea is a sensitive environment to eutrophication pressures. The main body of water of the Mediterranean is characterized by very low nutrient concentrations, and therefore, the Mediterranean is classified among the most oligotrophic (very poor waters in nutrients) seas of the world's oceans. However, some coastal areas, mainly in the northern part of the basin, receive excessive loads of nutrients from sewage effluents, river fluxes, aquaculture farms, fertilizers, and industrial facilities, showing intense eutrophic phenomena with many adverse effects for the marine ecosystem and humans. Various national and international authorities, in addition to monitoring, have taken legal and administrative measures to mitigate eutrophication trends in the area. The Mediterranean environment is a good paradigm of integration of extensive legal framework, scientific knowledge, and administrative practices. The Barcelona Convention, the Mediterranean Action Plan, and European Union Directives on water quality and coastal management, together with scientific information derived from international research programs in the Mediterranean, provide a sound background for practical actions in eutrophication problems. In the present work, the problem of coastal eutrophication in the Mediterranean is reviewed in connection with public policies of the Mediterranean States based on national and international legislation and scientific knowledge on Mediterranean oceanography-ecology and actions coordinated by international bodies. These common actions and practices on coastal management are also discussed in relation to the need for sustainable development and protection of the coastal zone in the Mediterranean Sea.

  15. Measuring Implicit European and Mediterranean Landscape Identity: A Tool Proposal

    PubMed Central

    Fornara, Ferdinando; Dentale, Francesco; Troffa, Renato; Piras, Simona

    2016-01-01

    This study presents a tool – the Landscape Identity Implicit Association Test (LI-IAT) – devoted to measure the implicit identification with European and Mediterranean landscapes. To this aim, a series of prototypical landscapes was selected as stimulus, following an accurate multi-step procedure. Participants (N = 174), recruited in two Italian cities, performed two LI-IATs devoted to assess their identification with European vs. Not-European and Mediterranean vs. Not-Mediterranean prototypical landscapes. Psychometric properties and criterion validity of these measures were investigated. Two self-report measures, assessing, respectively, European and Mediterranean place identity and pleasantness of the target landscapes, were also administered. Results showed: (1) an adequate level of internal consistency for both LI-IATs; (2) a higher identification with European and Mediterranean landscapes than, respectively, with Not-European and Not-Mediterranean ones; and (3) a significant positive relationship between the European and Mediterranean LI-IATs and the corresponding place identity scores, also when pleasantness of landscapes was controlled for. Overall, these findings provide a first evidence supporting the reliability and criterion validity of the European and Mediterranean LI-IATs. PMID:27642284

  16. INTRODUCTION: DESERTIFICATION AND SECURITY - PERSPECTIVES FOR THE MEDITERRANEAN REGION

    EPA Science Inventory

    This book focuses on two basic concepts: security and desertification in the Mediterranean Region and their linkages. It emerged from a single meeting of the "Workshop on Desertification in the Mediterranean Region. A Security Issue" held in Valencia, Spain on 2-5 December 2003...

  17. The multidecadal component of the Mediterranean summer variability

    NASA Astrophysics Data System (ADS)

    OrtizBevia, M. J.; RuizdeElvira, A.; Alvarez-Garcia, F. J.; Tasambay-Salazar, M.

    2016-11-01

    This study targets the low frequency components of the anomalous Mediterranean summer climatic variability. This last is characterised here by two indexes obtained from a statistical analysis of Mediterranean sea surface temperature anomalies. The evolution of the first of them, the Western Mediterranean Index, is dominated by a multidecadal timescale. This Index has a strong statistical impact on the summer air temperature anomalies in the European region. In the other index, the Mediterranean Dipole Index, the decadal timescale plays a major part. This last Index is linked to anomalous summer precipitations in some central European regions. A statistical methodology is used in order to identify some feedback relationships between the two Mediterranean indexes and other climate indexes which characterise some global or regional variability. In the case of the Western Mediterranean Index, the analysis reveals significant feedback relationships with two of these indexes. The selected predictors are introduced as variables in a statistical feedback model. The cross-skills scored in a cross-validation hindcast experiment reveals an important potential predictability. In this way, the multidecadal Mediterranean summer sea surface temperature variability appears as the result of two forcings, one related to the north-western Atlantic processes and the other connected to the north tropical Atlantic, and to a weak feedback onto the Atlantic. In the case of the Mediterranean Dipole Mode Index we have not found enough predictive potential in the feedback relationships identified.

  18. Comparison of Mediterranean diet compliance between European and non-European populations in the Mediterranean basin.

    PubMed

    Benhammou, Samira; Heras-González, Leticia; Ibáñez-Peinado, Diana; Barceló, Carla; Hamdan, May; Rivas, Ana; Mariscal-Arcas, Miguel; Olea-Serrano, Fatima; Monteagudo, Celia

    2016-12-01

    Fruit, vegetables, cereals, and olive oil are common elements of the Mediterranean diet (MD), but each country in the Mediterranean basin has its own gastronomic customs influenced by socio-cultural, religious, and economic factors. This study compared the dietary habits of three Mediterranean populations with different cultures and lifestyles, a total of 600 adults (61.9% females) between 25 and 70 yrs from Spain, Morocco, and Palestine. All participants completed a self administered questionnaire, including sociodemographic and anthropometric items, a validated semi-quantitative food frequency questionnaire adapted to the foods consumed in each country, and three 24-h recalls. MD adherence was estimated with the MD Serving Score (MDSS). All populations showed a moderate adherence to the Mediterranean dietary pattern. In comparison to the Palestine population, MDSS-assessed adherence to the MD was 6.36-fold higher in the Spanish population and 3.88-fold higher in the Moroccan population. Besides the country of origin, age was another predictive factor of MD adherence, which was greater (higher MDSS) in participants aged over 50 yrs than in those aged 30 yrs or younger. This preliminary study contributes initial data on dietary differences between European and non-European countries in the Mediterranean basin. The Spanish diet was shown to be closer to MD recommendations than the diet of Morocco or Palestine. Given the impact of good dietary habits on the prevention of chronic non-transmittable diseases, health policies should focus on adherence to a healthy diet, supporting traditional dietary patterns in an era of intense commercial pressures for change.

  19. Medieval iconography of watermelons in Mediterranean Europe

    PubMed Central

    Paris, Harry S.; Daunay, Marie-Christine; Janick, Jules

    2013-01-01

    Background and Aims The watermelon, Citrullus lanatus (Cucurbitaceae), is an important fruit vegetable in the warmer regions of the world. Watermelons were illustrated in Mediterranean Antiquity, but not as frequently as some other cucurbits. Little is known concerning the watermelons of Mediterranean Europe during medieval times. With the objective of obtaining an improved understanding of watermelon history and diversity in this region, medieval drawings purportedly of watermelons were collected, examined and compared for originality, detail and accuracy. Findings The oldest manuscript found that contains an accurate, informative image of watermelon is the Tractatus de herbis, British Library ms. Egerton 747, which was produced in southern Italy, around the year 1300. A dozen more original illustrations were found, most of them from Italy, produced during the ensuing two centuries that can be positively identified as watermelon. In most herbal-type manuscripts, the foliage is depicted realistically, the plants shown as having long internodes, alternate leaves with pinnatifid leaf laminae, and the fruits are small, round and striped. The manuscript that contains the most detailed and accurate image of watermelon is the Carrara Herbal, British Library ms. Egerton 2020. In the agriculture-based manuscripts, the foliage, if depicted, is not accurate, but variation in the size, shape and coloration of the fruits is evident. Both red-flesh and white-flesh watermelons are illustrated, corresponding to the typical sweet dessert watermelons so common today and the insipid citron watermelons, respectively. The variation in watermelon fruit size, shape and coloration depicted in the illustrations indicates that at least six cultivars of watermelon are represented, three of which probably had red, sweet flesh and three of which appear to have been citrons. Evidently, citron watermelons were more common in Mediterranean Europe in the past than they are today. PMID:23904443

  20. Proposal of a Mediterranean Diet Serving Score

    PubMed Central

    Monteagudo, Celia; Mariscal-Arcas, Miguel; Rivas, Ana; Lorenzo-Tovar, María Luisa; Tur, Josep A.; Olea-Serrano, Fátima

    2015-01-01

    Background and Aims Numerous studies have demonstrated a relationship between Mediterranean Diet (MD) adherence and the prevention of cardiovascular diseases, cancer, and diabetes, etc. The study aim was to validate a novel instrument to measure MD adherence based on the consumption of food servings and food groups, and apply it in a female population from southern Spain and determining influential factors. Methods and Results The study included 1,155 women aged 12-83 yrs, classified as adolescents, adults, and over-60-yr-olds. All completed a validated semi-quantitative food frequency questionnaire (FFQ). The Mediterranean Dietary Serving Score (MDSS) is based on the latest update of the Mediterranean Diet Pyramid, using the recommended consumption frequency of foods and food groups; the MDSS ranges from 0 to 24. The discriminative power or correct subject classification capacity of the MDSS was analyzed with the Receiver Operating Characteristic (ROC) curve, using the MDS as reference method. Predictive factors for higher MDSS adherence were determined with a logistic regression model, adjusting for age. According to ROC curve analysis, MDSS evidenced a significant discriminative capacity between adherents and non-adherents to the MD pattern (optimal cutoff point=13.50; sensitivity=74%; specificity=48%). The mean MDSS was 12.45 (2.69) and was significantly higher with older age (p<0.001). Logistic regression analysis showed highest MD adherence by over 60-year-olds with low BMI and no habit of eating between meals. Conclusions The MDSS is an updated, easy, valid, and accurate instrument to assess MD adherence based on the consumption of foods and food groups per meal, day, and week. It may be useful in future nutritional education programs to prevent the early onset of chronic non-transmittable diseases in younger populations. PMID:26035442

  1. Hyperglycaemia in pregnancy in Mediterranean women.

    PubMed

    Savona-Ventura, Charles; Vassallo, Josanne; Marre, Michel; Karamanos, Basil G

    2012-12-01

    New diagnostic criteria have recently been proposed that will result in a higher proportion of individuals being diagnosed as suffering from gestational diabetes mellitus (GDM) than previously. The present circum-Mediterranean study sets out to identify the relevance of the new criteria in this population. The study was a prospective, non-interventional, multicentre study in the Mediterranean region. A convenient sample of 1,368 pregnant women was recruited. All participants underwent a 75 g oGTT subdivided into five different glycaemic categories. The women's anthropomorphic and biological data, together with obstetric and infant outcomes, were collected. There was a threefold increase in diagnosis using the new criteria. Most of the biological characteristics generally associated with GDM showed high specificity and low sensitivity values. The biological characteristics, including maternal age, BMI and FBG, showed a progressive increase as a function of maternal glycaemia with moderate sensitivity and specificity values. Using these latter characteristics in combination ensures that 72.3 % of the GDM population would be correctly identified, while an oGTT would only be required in 18.7 % of the population. The progressive relationship of increasing glycaemia to adverse characteristics suggests that the new IADPSG criteria are reasonable provided that dietary advice is given to all pregnant women. In situations of economic restraints, it appears possible to screen Mediterranean women for GDM risk using a composite model using FBG >5.0 mmol/l combined with the performance of an oGTT in women with a low FBG but who are overweight and aged >30 years.

  2. Relationships between deep-sea tunicate populations west and east of the Straits of Gibraltar

    NASA Astrophysics Data System (ADS)

    Monniot, Claude; Monniot, Françoise

    Twenty-four species of tunicates were collected from deep bottoms on each side of the Gibraltar sill, in the adjacent Mediterranean Sea and Atlantic Ocean. In the Atlantic, stations bathed by Atlantic and Mediterranean waters were both sampled. No transport of ascidian taxa by the outflow of Mediterranean water into the Atlantic is apparent. The alternative hypothesis of an Atlantic origin of bathyal ascidian species in the Mediterranean Sea is proposed.

  3. Human health benefits supplied by Mediterranean marine biodiversity.

    PubMed

    Lloret, Josep

    2010-10-01

    This paper summarizes the overall benefits supplied by Mediterranean marine biodiversity to human health and highlights the anthropogenic and environmental causes that are threatening these benefits. First, the Mediterranean Sea is a valuable source of seafood, which is an important component of the so-called "Mediterranean diet". This type of diet has several health benefits, including cardio and cancer protective effects, which are attributed to the high intake of seafood-derived n-3 (omega-3) fatty acids. Second, the Mediterranean marine organisms, particularly the benthic ones, have furnished a large variety of bioactive metabolites, some of which are being developed into new drugs to threat major human diseases such as cancer. Third, the Mediterranean coastal areas provide environments for practising maritime leisure activities that provide physical and psychological benefits to users. Despite all this, fishing, tourism, contamination and sea warming are deteriorating this rich marine ecosystem, which needs to be protected to assure human welfare.

  4. Nutritional and cultural aspects of the Mediterranean diet.

    PubMed

    Serra-Majem, Lluis; Bach-Faig, Anna; Raidó-Quintana, Blanca

    2012-06-01

    The recent recognition by United Nations Educational, Scientific and Cultural Organization (UNESCO) of the Mediterranean diet as an Intangible Cultural Heritage of Humanity reinforces, together with the scientific evidence, the Mediterranean diet as a cultural and health model. The Mediterranean diet has numerous beneficial effects on among others the immune system, against allergies, on the psyche, or even on quality of life, topics that are currently fields of research. The Mediterranean diet has an international projection; it is regarded as the healthiest and the most sustainable eating pattern on the planet and is a key player in the public health nutrition field globally, but especially in the Mediterranean area. Moreover, this ancient cultural heritage should be preserved and promoted from different areas: public health, agriculture, culture, politics, and economic development.

  5. Study of Anticyclogenesis Affecting the Mediterranean

    NASA Astrophysics Data System (ADS)

    Hatzaki, M.; Flocas, H. A.; Simmonds, I.; Kouroutzoglou, J.; Garde, L.; Keay, K.; Bitsa, E.

    2014-12-01

    A comprehensive climatology of migratory anticyclones affecting the Mediterranean was generated by the University of Melbourne finding and tracking algorithm (MS algorithm), applied to 34 years (1979-2012) of ERA-Interim MSLP on a 1.5°x1.5° resolution. The algorithm was employed for the first time for anticyclones in this region, thus, its robustness and reliability in efficiently capturing the individual characteristics of the anticyclonic tracks in such a closed basin with complex topography were checked and verified. Then, the tracks and the statistical properties of the migratory systems were calculated and analyzed. Considering that cold-core anticyclones are shallow and weaken with height contrary to the warm-core that exhibit a vertically well-organized structure, the vertical thermal extend of the systems was studied with an algorithm developed as an extension module of the MS algorithm using ERA-Interim temperatures on several isobaric levels from 1000hPa to 100hPa on an 1.5°x1.5° resolution. The results verified that during both cold and warm period, cold-core anticyclones mainly affect the northern parts of the Mediterranean basin, with their behavior to be strongly regulated by cyclonic activity from the main storm track areas of the North Atlantic and Europe. On the other hand, warm-core anticyclones were found mainly in the southern Mediterranean and North African areas. Here, in order to get a perspective on the dynamic and thermodynamic processes in anticyclonic formation, a dynamical analysis at several vertical levels is performed. The study of mean fields of potential vorticity, temperature advection, vorticity advection at various levels can elucidate the role of upper and low levels during anticyclogenesis and system evolvement and help to further understand the dynamic mechanisms which are responsible for the anticyclogenesis over the Mediterranean region. Acknowledgement: This research project is implemented within the framework of the

  6. Phytotoxic activities of Mediterranean essential oils.

    PubMed

    de Almeida, Luiz Fernando Rolim; Frei, Fernando; Mancini, Emilia; De Martino, Laura; De Feo, Vincenzo

    2010-06-14

    Twelve essential oils from Mediterranean aromatic plants were tested for their phytotoxic activity, at different doses, against the germination and the initial radicle growth of seeds of Raphanus sativus, Lactuca sativa and Lepidium sativum. The essential oils were obtained from Hyssopus officinalis, Lavandula angustifolia, Majorana hortensis, Melissa officinalis, Ocimum basilicum, Origanum vulgare, Salvia officinalis and Thymus vulgaris (Lamiaceae), Verbena officinalis (Verbenaceae), Pimpinella anisum, Foeniculum vulgare and Carum carvi (Apiaceae). The germination and radicle growth of tested seeds were affected in different ways by the oils. Thyme, balm, vervain and caraway essential oils were more active against both germination and radicle elongation.

  7. Severe Weather Guide - Mediterranean Ports - 24. Cartagena

    DTIC Science & Technology

    1988-08-01

    number) This handbook for the port of Cartagena, one in a series of severe weather guides for Mediterranean ports, provides decision-making guidance for... handbook is organized in four sections for ready reference: general guidance on handbook content and use; a quick-look captain’s summary; a more...34 R - 8 8 - RC (20) Un c lass i -f i ed rep or t DE (23) *PORTS, (FACILITIES), *1A|EA! HER, HANDBOOKS , HAZARDS, riED I 1 ::;;.;■ :H.:i:;;.HN EiEA

  8. Mediterranean Holocene climate, environment and human societies

    NASA Astrophysics Data System (ADS)

    Holmgren, Karin; Gogou, Alexandra.; Izdebski, Adam.; Luterbacher, Juerg.; Sicre, Marie-Alexandrine; Xoplaki, Elena

    2016-03-01

    This paper introduces the reader to a special issue of articles that explores links and processes behind societal change, climate change and environmental change in a Holocene perspective in the Mediterranean region. All papers are, by purpose, co-authored by scientists representing different disciplines. The cross-cutting theme has been to reach beyond simple explanations of potential climate-society relationships and advance our understanding on how to improve research methods and theories in the field. The thirteen papers in this issue address these questions in three different ways, by i) conceptual/methodological approaches; ii) review papers; and iii) case studies.

  9. Familial Mediterranean fever: An updated review

    PubMed Central

    Sarı, İsmail; Birlik, Merih; Kasifoğlu, Timuçin

    2014-01-01

    Familial Mediterranean Fever (FMF) is a hereditary autoinflammatory disorder characterised by acute attacks of fever and serosal inflammation. FMF primarily affects Jewish, Armenian, Turkish, and Arab populations. The disease is accompanied by a marked decrease in quality of life due to the effects of attacks and subclinical inflammation in the attack-free periods. Untreated or inadequately treated patients run the risk of amyloidosis, which is an important cause of morbidity and mortality. In this review, the current information available on FMF is summarised. PMID:27708867

  10. Mediterranean Diet and Its Correlates among Adolescents in Non-Mediterranean European Countries: A Population-Based Study

    PubMed Central

    Novak, Dario; Štefan, Lovro; Prosoli, Rebeka; Emeljanovas, Arunas; Mieziene, Brigita; Milanović, Ivana; Radisavljević-Janić, Snežana

    2017-01-01

    Little is known about the factors which might influence the adherence to a Mediterranean diet in non-Mediterranean European countries. Thus, the main purpose of this study was to determine the associations between socioeconomic, psychological, and physical factors on a Mediterranean diet. In this cross-sectional study, participants were 14–18-year-old adolescents (N = 3071) from two non-Mediterranean countries: Lithuania (N = 1863) and Serbia (N = 1208). The dependent variable was Mediterranean diet, and was assessed with the Mediterranean Diet Quality Index for children and adolescents questionnaire. Independent variables were gender, body-mass index, self-rated health, socioeconomic status, psychological distress, physical activity, and sedentary behavior. The associations between dependent and independent variables were analyzed by using logistic regression. Results showed that higher adherence to a Mediterranean diet was associated with higher self-rated health, socioeconomic status, and physical activity, yet low adherence to a Mediterranean diet was associated with being female, having higher body-mass index, psychological distress, and sedentary behavior. Our findings suggest that future studies need to explore associations between lifestyle habits—especially in target populations, such as primary and secondary school students. PMID:28241432

  11. [Wheat, bread and pasta in Mediterranean diets].

    PubMed

    Pérez Rodrigo, Carmen; Ruiz Vadillo, Virginia

    2004-06-01

    Cereals in diets have varied along evolution trends in food patterns. Cereals are starchy foods and are the main source of polysacharides in the diet. In Mediterranean countries, cereals have been used in different ways, though they are mainly used as refined cereals. Wheat bread is one of the most commonly used. In the average Spanish diet, considerable changes have taken place since 1961 leading to a significant decrease in percent energy from carbohydrate. At the same time, percent energy from fat has increased as web as protein intake. These changes in the nutritional pattern reflect a continuous decrease in consumption of grains and cereals, pulses and potatoes. In the last decades, consumption of pasta however has increased as web as consumption of processed bakery products and biscuits. Scientific and epidemiological evidence show that cereals should be the main source of energy in the diet, in line with the so-called Mediterranean Diet. Polysacharides should provide 50-55% energy. In order to reach that goal, cereal, legumes and potatoes should be included in the daily diet as 4-6 portions. Whole grain cereales should be preferred or food preparations combining pasta, potatoes or rice with vegetables in order to reduce the glycemic index. Processed bakery products and biscuits should be consumed in moderation.

  12. Tsunami Catalogues for the Eastern Mediterranean - Revisited.

    NASA Astrophysics Data System (ADS)

    Ambraseys, N.; Synolakis, C. E.

    2008-12-01

    We critically examine examine tsunami catalogues of tsunamis in the Eastern Mediterranean published in the last decade, by reference to the original sources, see Ambraseys (2008). Such catalogues have been widely used in the aftermath of the 2004 Boxing Day tsunami for probabilistic hazard analysis, even to make projections for a ten year time frame. On occasion, such predictions have caused panic and have reduced the credibility of the scientific community in making hazard assessments. We correct classification and other spurious errors in earlier catalogues and posit a new list. We conclude that for some historic events, any assignment of magnitude, even on a six point intensity scale is inappropriate due to lack of information. Further we assert that any tsunami catalogue, including ours, can only be used in conjunction with sedimentologic evidence to quantitatively infer the return period of larger events. Statistical analyses correlating numbers of tsunami events derived solely from catalogues with their inferred or imagined intensities are meaningless, at least when focusing on specific locales where only a handful of tsunamis are known to have been historically reported. Quantitative hazard assessments based on scenario events of historic tsunamis for which -at best- only the size and approximate location of the parent earthquake is known should be undertaken with extreme caution and only with benefit of geologic studies to enhance the understanding of the local tectonics. Ambraseys N. (2008) Earthquakes in the Eastern Mediterranean and the Middle East: multidisciplinary study of 2000 years of seimicity, Cambridge Univ. Press, Cambridge (ISBN 9780521872928).

  13. Sprite climatology in the Eastern Mediterranean Region

    NASA Astrophysics Data System (ADS)

    Yair, Yoav; Price, Colin; Katzenelson, Dor; Rosenthal, Neta; Rubanenko, Lior; Ben-Ami, Yuval; Arnone, Enrico

    2015-04-01

    We present statistical analysis of 436 sprites observed in 7 winter campaigns from 2006/7-2012/13. Results show a clear peak in the frequency of sprite detections, with maximum values (< 40% of events) between 00:30 and 02:15 LST (22:30-00:15 UT; LST = UT + 2). The detection times of sprites are well-correlated with a relative increase in the fraction of + CG strokes, which exhibit maxima between 00:00 and 02:00 LST. The morphological distribution of 339 sprites, that we were able to clearly identify, is dominated by column sprites (49.3%), with angels (33.0%) and carrots (25.7%) being less frequent. This is similar to reports of winter sprites over the Sea of Japan and summer ones in Central Europe. Other shapes such as trees, wishbones, etc. appear quite rarely. Single element events constitute 16.5% of observations, with 83.5% containing 2 elements or more. Clusters of homogenous types are slightly more frequent than mixed ones (55%). Our observations suggest winter Mediterranean thunderstorms to have a vertical structure in between high tropical convective systems and the lower cloud-top cells in Japan. The climatology shows the Eastern Mediterranean to be a major sprite producer in Northern Hemisphere winter, and offers ground-based coverage for future space missions.

  14. Sprite Climatology in the Eastern Mediterranean Region

    NASA Astrophysics Data System (ADS)

    Yair, Yoav; Price, Colin; Katzenelson, Dor; Rosenthal, Neta; Rubanenko, Lior; Ben-Ami, Yuval; Arnone, Enrico

    2015-04-01

    We present statistical analysis of 436 sprites observed in 7 winter campaigns from 2006/7-2012/13. Results show a clear peak in the frequency of sprite detections, with maximum values (< 40% of events) between 00:30-02:15 LST (22:30-00:15 UT; LST=UT+2). The detection times of sprites are well-correlated with a relative increase in the fraction of +CG strokes, which exhibit maxima between 00:00-02:00 LST. The morphological distribution of 339 sprites, that we were able to clearly identify, is dominated by column sprites (49.3%), with angels (33.0%) and carrots (25.7%) being less frequent. This is similar to reports of winter sprites over the Sea of Japan and summer ones in central Europe. Other shapes such as trees, wishbones, etc. appear quite rarely. Single element events constitute 16.5% of observations, with 83.5% containing 2 elements or more. Clusters of homogeneous types are slightly more frequent than mixed ones (55%). Our observations suggest winter East Mediterranean thunderstorms to have a vertical structure that is an intermediate type between high tropical convective systems and the lower cloud-top cells in winter thunderstorms over the Sea of Japan. The climatology shows that the Eastern Mediterranean is a major sprite producer during Northern Hemisphere winter, and thus the existing and future optical observation infrastructure in Israel offers ground-based coverage for upcoming space missions that aim to map global sprite activity.

  15. Floating debris in the Mediterranean Sea.

    PubMed

    Suaria, Giuseppe; Aliani, Stefano

    2014-09-15

    Results from the first large-scale survey of floating natural (NMD) and anthropogenic (AMD) debris (>2 cm) in the central and western part of the Mediterranean Sea are reported. Floating debris was found throughout the entire study area with densities ranging from 0 to 194.6 items/km(2) and mean abundances of 24.9 AMD items/km(2) and 6.9 NMD items/km(2) across all surveyed locations. On the whole, 78% of all sighted objects were of anthropogenic origin, 95.6% of which were petrochemical derivatives (i.e. plastic and styrofoam). Maximum AMD densities (>52 items/km(2)) were found in the Adriatic Sea and in the Algerian basin, while the lowest densities (<6.3 items/km(2)) were observed in the Central Tyrrhenian and in the Sicilian Sea. All the other areas had mean densities ranging from 10.9 to 30.7 items/km(2). According to our calculations, more than 62 million macro-litter items are currently floating on the surface of the whole Mediterranean basin.

  16. Sexual dimorphism and age of Mediterranean salamanders.

    PubMed

    Reinhard, Sandy; Renner, Sandra; Kupfer, Alexander

    2015-02-01

    We analysed sexual size dimorphism (SSD) for two Mediterranean species of the "true" salamander clade possessing distinct life histories (Salamandra algira and Mertensiella caucasica) and equilibrated the morphometric approach to individual age by using skeletochronology. For species that have a short breeding season and live at high altitudes, such as Mediterranean amphibians, the fecundity advantage hypothesis predicts female-biased SSD to maximise reproductive success. Our results showed no SSD in either species; however, morphometric data indicated a male-biased dimorphism in limb (arm and leg) dimensions in both species when compared to body size. Limb dimorphisms are likely related to the particular mating system, which involves an amplexus during spermatophore transfer. Arm length appeared sexually dimorphic during ontogeny both in viviparous S. algira and oviparous M. caucasica. A review on SSD indicated monomorphy of body size as a common lineage-specific pattern among the "true" salamander clade, but also the common presence of other traits such as sexually dimorphic limb proportions.

  17. Thermohaline circulation in the Arctic Mediterranean Seas

    NASA Astrophysics Data System (ADS)

    Aagaard, K.; Swift, J. H.; Carmack, E. C.

    1985-05-01

    The renewal of the deep North Atlantic by the various overflows of the Greenland-Scotland ridges is only one manifestation of the convective and mixing processes which occur in the various basins and shelf areas to the north: the Arctic Ocean and the Greenland, Iceland, and Norwegian seas, collectively called the Arctic Mediterranean. The traditional site of deep ventilation for these basins is the Greenland Sea, but a growing body of evidence also points to the Arctic Ocean as a major source of deep water. This deep water is relatively warm and saline, and it appears to be a mixture of dense, brine-enriched shelf water with intermediate strata in the Arctic Ocean. The deep water exits the Arctic Ocean along the Greenland slope to mix with the Greenland Sea deep water. Conversely, very cold low-salinity deep water from the Greenland Sea enters the Arctic Ocean west of Spitsbergen. Within the Arctic Ocean, the Lomonosov Ridge excludes the Greenland Sea deep water from the Canadian Basin, leaving the latter warm, saline, and rich in silica. In general, the entire deep-water sphere of the Arctic Mediterranean is constrained by the Greenland-Scotland ridges to circulate internally. Therefore it is certain of the intermediate waters formed in the Greenland and Iceland seas which ventilate the North Atlantic. These waters have a very short residence time in their formation areas and are therefore able to rapidly transmit surface-induced signals into the deep North Atlantic.

  18. Tracking rainfall in the northern Mediterranean borderlands during sapropel deposition

    NASA Astrophysics Data System (ADS)

    Toucanne, Samuel; Angue Minto'o, Charlie Morelle; Fontanier, Christophe; Bassetti, Maria-Angela; Jorry, Stephan J.; Jouet, Gwenaël

    2015-12-01

    The role of mid-latitude precipitation in the hydrological forcing leading to the deposition of sapropels in the Mediterranean Sea remains unclear. The new GDEC-4-2 borehole, East Corsica margin (northern Tyrrhenian Sea), provides the first precisely dated evidence for enhanced rainfall in the Western Mediterranean during warm intervals of interglacial periods over the last 547 kyr. Comparison of GDEC-4-2 proxy records with pollen sequences and speleothems from the central and eastern Mediterranean reveals that these pluvial events were regional in character and occurred probably in response to the intensification of the Mediterranean storm track along the northern Mediterranean borderlands in autumn/winter. Our dataset suggests that the timing of maxima of the Mediterranean autumn/winter storm track precipitation coincide with that of the North African summer monsoon and sapropel deposition. Besides highlighting a close coupling between mid- and low-latitude hydrological changes, our findings suggest that during warm intervals of interglacial periods the reduced sea-surface water salinities, together with the high flux of nutrient and organic matter, produced by the monsoonal Nile (and wadi-systems) floods, were maintained throughout the winter by the Mediterranean rainfall. This provides an important additional constraint on the hydrological perturbation causing sapropel formation.

  19. Occurrence of Diopatra marocensis (Annelida, Onuphidae) in the eastern Mediterranean

    PubMed Central

    Çinar, Melih Ertan; Fauchald, Kristian; Dagli, Ertan

    2014-01-01

    Abstract The present study deals with the presence of Diopatra marocensis in the eastern Mediterranean. This species is small-sized and inhabited muddy bottom near the opening of rivers or lagoons [salinity range: 33−39‰] in the Aegean and Levantine Seas, and reached a maximum density of 90 ind.m-2 in Mersin Bay. This species might be an alien species that was introduced from the East Atlantic (near Gibraltar) to the eastern Mediterranean via ballast water of ships, as it has never been reported from the western Mediterranean Sea. PMID:25349504

  20. Global and Mediterranean climate change: a short summary.

    PubMed

    Ciardini, Virginia; Contessa, Gian Marco; Falsaperla, Rosaria; Gómez-Amo, José Luis; Meloni, Daniela; Monteleone, Francesco; Pace, Giandomenico; Piacentino, Salvatore; Sferlazzo, Damiano; di Sarra, Alcide

    2016-01-01

    Observed changes at the global scale. An increase of the annual mean global temperature and changes of other climate parameters have been observed in the last century. The global temperature and the atmospheric concentration of greenhouse gases are changing at a very fast pace compared to those found in palaeoclimate records. Changes in the Mediterranean. Variations of some climate change indicators can be much larger at the local than at the global scale, and the Mediterranean has been indicated among the regions most sensitive to climate change, also due to the increasing anthropogenic pressure. Model projections for the Mediterranean foresee further warming, droughts, and long-lasting modifications.

  1. Diversity, distribution and population size structure of deep Mediterranean gorgonian assemblages (Menorca Channel, Western Mediterranean Sea)

    NASA Astrophysics Data System (ADS)

    Grinyó, Jordi; Gori, Andrea; Ambroso, Stefano; Purroy, Ariadna; Calatayud, Clara; Dominguez-Carrió, Carlos; Coppari, Martina; Lo Iacono, Claudio; López-González, Pablo J.; Gili, Josep-Maria

    2016-06-01

    Gorgonians are a key group of organisms in benthic marine communities with a wide bathymetric and geographical distribution. Although their presence on continental shelves and slopes has been known for more than 100 years, knowledge concerning the ecology of deep gorgonian species is still in a very preliminary stage. To overcome this situation, gorgonian assemblages located at 40-360 m depth were studied over a large geographical area on the continental shelf and upper slope of the Menorca Channel (Western Mediterranean Sea). A quantitative analysis of video transects recorded by a manned submersible and a remotely operated vehicle, were used to examine the diversity, distribution and demography of gorgonian species. Results showed high gorgonian diversity within this depth range (a total of nine species were observed) compared to Mediterranean coastal areas. Gorgonian assemblages on the continental shelf and upper slope were mostly monospecific (respectively 73% and 76% of occupied sampling units contained one single species), whereas shelf edge assemblages were highly multispecific (92% of occupied sampling units contained several species). This contrasts with the monospecificity of Mediterranean coastal gorgonian assemblages. Gorgonian populations on the continental shelf were mostly dominated by small colonies (88% of measured colonies) with few intermediate and large colonies (12% of measured colonies). In deeper areas small colonies were still dominant (60% of measured colonies), but intermediate and large colonies were much more abundant (40% of measured colonies). This suggests high recruitment rates on the continental shelf, but perturbations (trammel nets, long lines and strong storms) may limit the presence of intermediate and large colonies. Conversely, on the shelf edge and upper slope a more stable environment may allow colonies to reach larger dimensions. The identification and ecological characterization of these deep assemblages further extends

  2. Niche relations among three sympatric Mediterranean carnivores.

    PubMed

    Fedriani, Jose M; Palomares, Francisco; Delibes, Miguel

    1999-10-01

    Previous studies carried out in the Doñana National Park reported that red foxes (Vulpes vulpes) were killed by Iberian lynxes (Lynx pardinus), whereas similar-sized Eurasian badgers (Meles meles) were not. Therefore, we predicted that fox would avoid lynx predation risk by niche segregation whereas we did not expect such a segregation between badger and lynx. As an approach for evaluating our predictions, we compared their diet, activity patterns, and habitat use in an area of Doñana where the three carnivores are sympatric. Lynxes preyed almost uniquely on European rabbits (Oryctolagus cuniculus), and though badgers and foxes were omnivorous, rabbits also were a major prey, resulting in high overlaps throughout the year. However, badgers preyed largely on small rabbits, whereas lynxes and foxes preyed mainly on medium-sized rabbits. There were also interspecific differences in activity patterns. Maximum levels of activity among lynxes were during sunrise and dusk (49-67%). Foxes were most active during dusk and night (34-67%), and badgers were mainly nocturnal (53-87%). Though there were seasonal differences in the amount of activity of each species, specific activity patterns changed little throughout the year. There was a strong difference in annual habitat use by the three species (P < 0.0001). Lynxes used mainly the Mediterranean scrubland during both the active (PMAX) and the resting (PMIN) periods. During PMIN, foxes used the Mediterranean scrubland intensively (40% of locations on average), but during PMAX, they used the pastureland much more intensively despite this habitat being poorer in their main prey (rabbits). As a consequence, foxes and lynxes exhibited segregation in their habitat use during the active period. Badgers also used the Mediterranean scrubland intensively, especially during PMIN. There were no seasonal differences in habitat use for lynx and fox, but there was for badgers (P < 0.015). Within the study area, the three species

  3. The Mediterranean Forecasting System: recent developments

    NASA Astrophysics Data System (ADS)

    Tonani, Marina; Oddo, Paolo; Korres, Gerasimos; Clementi, Emanuela; Dobricic, Srdjan; Drudi, Massimiliano; Pistoia, Jenny; Guarnieri, Antonio; Romaniello, Vito; Girardi, Giacomo; Grandi, Alessandro; Bonaduce, Antonio; Pinardi, Nadia

    2014-05-01

    Recent developments of the Mediterranean Monitoring and Forecasting Centre of the EU-Copernicus marine service, the Mediterranean Forecasting System (MFS), are presented. MFS provides forecast, analysis and reanalysis for the physical and biogeochemical parameters of the Mediterranean Sea. The different components of the system are continuously updated in order to provide to the users the best available product. This work is focus on the physical component of the system. The physical core of MFS is composed by an ocean general circulation model (NEMO) coupled with a spectral wave model (Wave Watch-III). The NEMO model provides to WW-III surface currents and SST fields, while WW-III returns back to NEMO the neutral component of the surface drag coefficient. Satellite Sea Level Anomaly observations and in-situ T & S vertical profiles are assimilated into this system using a variational assimilation scheme based on 3DVAR (Dobricic, 2008) . Sensitive experiments have been performed in order to assess the impact of the assimilation of the latest available SLA missions, Altika and Cryosat together with the long term available mission of Jason2. The results show a significant improvement of the MFS skill due to the multi-mission along track assimilation. The primitive equations module has been recently upgraded with the introduction of the atmospheric pressure term and a new, explicit, numerical scheme has been adopted to solve the barotropic component of the equations of motion. The SLA satellite observations for data assimilation have been consequently modified in order to account for the new atmospheric pressure term introduced in the equations. This new system has been evaluated using tide gauge coastal buoys and the satellite along track data. The quality of the SSH has improved significantly while a minor impact has been observed on the other state variables (temperature, salinity and currents). Experiments with a higher resolution NWP (numerical weather prediction

  4. Sclerites in different tissues of Mediterranean Echinodermata.

    PubMed

    Ocaña Martín, Amelia; Tierno de Figueroa, J Manuel; Palomino-Morales, Rogelio J

    2006-06-01

    The presence of sclerites in different mesodermal tissues was studied in thirteen species of Mediterranean echinoderms representing the five living classes. In the species of Asteroidea and Crinoidea examined, sclerites were present only in specific tissues. In the species of Ophiuroidea and, especially, Echinoidea and Holothuroidea examined, sclerites were present in almost every tissue, but with considerable variation among species and tissues. Data on sclerite shape, size, and relative abundance (measured as tissue abundance) are presented. The data support the possible functional role of sclerites as reinforcing structures, as well as their possible use as taxonomic characters. Finally, the need of more studies to elucidate the ontogenetic and phylogenetic implications of sclerites is discussed.

  5. Least Disturbed Condition for European Mediterranean rivers.

    PubMed

    Feio, M J; Aguiar, F C; Almeida, S F P; Ferreira, J; Ferreira, M T; Elias, C; Serra, S R Q; Buffagni, A; Cambra, J; Chauvin, C; Delmas, F; Dörflinger, G; Erba, S; Flor, N; Ferréol, M; Germ, M; Mancini, L; Manolaki, P; Marcheggiani, S; Minciardi, M R; Munné, A; Papastergiadou, E; Prat, N; Puccinelli, C; Rosebery, J; Sabater, S; Ciadamidaro, S; Tornés, E; Tziortzis, I; Urbanič, G; Vieira, C

    2014-04-01

    The present report describes a three-step approach that was used to characterize and define thresholds for the Least Disturbed Condition in Mediterranean streams of four different types, regarding organic pollution and nutrients, hydrological and morphological alterations, and land use. For this purpose, a common database composed of national reference sites (929 records) from seven countries, sampled for invertebrates, diatoms and macrophytes was used. The analyses of reference sites showed that small (catchment <100 km(2)) siliceous and non-siliceous streams were mainly affected by channelization, bank alteration and hydropeaking. Medium-sized siliceous rivers were the most affected by stressors: 25-43% of the samples showed at least slight alterations regarding channelization, connectivity, upstream dam influence, hydropeaking and degradation of riparian vegetation. Temporary streams were the least affected by hydromorphological changes, but they were nevertheless affected by alterations in riparian vegetation. There were no major differences between all permanent stream types regarding water quality, but temporary streams showed lower values for oxygenation (DO) and wider ranges for other variables, such as nitrates. A lower threshold value for DO (60%) was determined for this stream type and can be attributed to the streams' natural characteristics. For all other river types, common limits were found for the remaining variables (ammonium, nitrate, phosphate, total P, % of artificial areas, % of intensive and extensive agriculture, % of semi-natural areas in the catchment). These values were then used to select the list of reference sites. The biological communities were characterized, revealing the existence of nine groups of Mediterranean invertebrate communities, six for diatoms and five for macrophytes: each group was characterized by specific indicator taxa that highlighted the differences between groups.

  6. More Signs Mediterranean Diet May Boost Your Brain

    MedlinePlus

    ... habits common in Mediterranean countries -- lots of fruits, vegetables, olive oil and beans -- retained more brain volume compared to ... diet is an eating style that emphasizes fruits, vegetables, olive oil instead of butter, beans and cereal grains, such ...

  7. Mediterranean Sea level variations during the Messinian salinity crisis

    NASA Astrophysics Data System (ADS)

    Gargani, Julien; Rigollet, Christophe

    2007-05-01

    The Mediterranean Basin has not always been connected to the Atlantic Ocean. During the Messinian salinity crisis (MSC), the Mediterranean Sea became progressively isolated by a complex combination of tectonic and glacio-eustatic processes. When isolated, the Mediterranean water level depends on the hydrological flux and is expected to vary significantly. The amplitude and number of large water level fluctuations in the isolated Mediterranean is still controversial, despite numerous geological investigations. The observation of 3-5 surfaces of erosion in the Nile delta (Eastern Basin) provides new elements for understanding the dynamics of the MSC. Our model demonstrates that numerous water level falls of short duration may explain the preservation of a discontinuous river profile at ~-500 m and ~-1500 m in the Western Basin, as well as the existence of deep surfaces of erosion in the Eastern Basin.

  8. Mediterranean Diet: Choose This Heart-Healthy Diet Option

    MedlinePlus

    ... of healthy eating — plus a splash of flavorful olive oil and perhaps a glass of red wine — ... eat a Mediterranean diet supplemented with extra-virgin olive oil and mixed nuts may have a reduced ...

  9. [The mediterranean diet model in inflammatory rheumatic diseases].

    PubMed

    Sales, C; Oliviero, F; Spinella, P

    2009-01-01

    The Mediterranean diet is based on a pattern of eating closely tied to the Mediterranean region, which includes Greece and southern Italy. Essentially, the traditional diet emphasizes foods from plant sources, limited meat consumption, small amounts of wine and olive oil as the main fat source. The beneficial effects of the Mediterranean diet has been proven not only to cardiovascular diseases but also for diabetes, obesity, arthritis and cancer. Its anti-inflammatory and protective properties are linked to the large presence of omega-3 polyunsaturated fatty acids, vitamins, but especially to the constituents of extra virgin olive oil: oleic acid, phenolic compounds olecanthal, a new recently discovered molecule, with natural anti-inflammatory properties. It has been shown that the Mediterranean diet can reduce disease activity, pain and stiffness in patients with inflammatory arthritis and may thus constitute a valuable support for patients suffering from these diseases.

  10. Visceral Leishmaniasis and HIV Coinfection in the Mediterranean Region

    PubMed Central

    Monge-Maillo, Begoña; Norman, Francesca F.; Cruz, Israel; Alvar, Jorge; López-Vélez, Rogelio

    2014-01-01

    Visceral leishmaniasis is hypoendemic in Mediterranean countries, where it is caused by the flagellate protozoan Leishmania infantum. VL cases in this area account for 5%–6% of the global burden. Cases of Leishmania/HIV coinfection have been reported in the Mediterranean region, mainly in France, Italy, Portugal, and Spain. Since highly active antiretroviral therapy was introduced in 1997, a marked decrease in the number of coinfected cases in this region has been reported. The development of new diagnostic methods to accurately identify level of parasitemia and the risk of relapse is one of the main challenges in improving the treatment of coinfected patients. Clinical trials in the Mediterranean region are needed to determine the most adequate therapeutic options for Leishmania/HIV patients as well as the indications and regimes for secondary prophylaxis. This article reviews the epidemiological, diagnostic, clinical, and therapeutic aspects of Leishmania/HIV coinfection in the Mediterranean region. PMID:25144380

  11. The Mediterranean interannual variability in MEDRYS, a Mediterranean Sea reanalysis over 1992-2013

    NASA Astrophysics Data System (ADS)

    Beuvier, Jonathan; Hamon, Mathieu; Lellouche, Jean-Michel; Greiner, Eric; Alias, Antoinette; Arsouze, Thomas; Benkiran, Mounir; Béranger, Karine; Drillet, Yann; Sevault, Florence; Somot, Samuel

    2015-04-01

    The French research community on the Mediterranean Sea and the French operational ocean forecasting center Mercator Océan are gathering their skills and expertises in physical oceanography, ocean modelling, atmospheric forcings and data assimilation, to carry out a MEDiterranean Sea ReanalYsiS (MEDRYS) at high resolution for the period 1992-2013. The reanalysis is used to have a realistic description of the ocean state over the recent decades and it will help to understand the long-term water cycle over the Mediterranean basin in terms of variability and trends, contributing thus to the HyMeX international program. The ocean model used is NEMOMED12 [Lebeaupin Brossier et al., 2011, Oc. Mod., 2012, Oc. Mod.; Beuvier et al., 2012a, JGR, 2012b, Mercator Newsl.], a Mediterranean configuration of NEMO [Madec and the NEMO Team, 2008], with a 1/12° (about 7 km) horizontal resolution and 75 vertical z-levels with partial steps. It is forced by the 3-hourly atmospheric fluxes coming from an ALADIN-Climate simulation at 12 km of resolution [Herrmann et al., 2011, NHESS], driven by the ERA-Interim atmospheric reanalysis. The exchanges with the Atlantic Ocean are performed through a buffer zone, with a damping on 3D theta-S and on sea level towards the ORA-S4 oceanic reanalysis [Balmaseda et al., 2012, QJRMS]. This model configuration is used to carry a 34-year free simulation over the period 1979-2013. This free simulation is the initial state of the reanalysis in October 1992. It is also used to compute anomalies from which the data assimilation scheme derives required characteristic covariances of the ocean model. MEDRYS1 uses the current Mercator Océan operational data assimilation system [Lellouche et al., 2013, Oc.Sci.]. It uses a reduced order Kalman filter with a 3D multivariate modal decomposition of the forecast error. A 3D-Var scheme corrects biases in temperature and salinity for the slowly evolving large-scale. In addition, some modifications dedicated to the

  12. A Phylogenetic Perspective on the Evolution of Mediterranean Teleost Fishes

    PubMed Central

    Meynard, Christine N.; Mouillot, David; Mouquet, Nicolas; Douzery, Emmanuel J. P.

    2012-01-01

    The Mediterranean Sea is a highly diverse, highly studied, and highly impacted biogeographic region, yet no phylogenetic reconstruction of fish diversity in this area has been published to date. Here, we infer the timing and geographic origins of Mediterranean teleost species diversity using nucleotide sequences collected from GenBank. We assembled a DNA supermatrix composed of four mitochondrial genes (12S ribosomal DNA, 16S ribosomal DNA, cytochrome c oxidase subunit I and cytochrome b) and two nuclear genes (rhodopsin and recombination activating gene I), including 62% of Mediterranean teleost species plus 9 outgroups. Maximum likelihood and Bayesian phylogenetic and dating analyses were calibrated using 20 fossil constraints. An additional 124 species were grafted onto the chronogram according to their taxonomic affinity, checking for the effects of taxonomic coverage in subsequent diversification analyses. We then interpreted the time-line of teleost diversification in light of Mediterranean historical biogeography, distinguishing non-endemic natives, endemics and exotic species. Results show that the major Mediterranean orders are of Cretaceous origin, specifically ∼100–80 Mya, and most Perciformes families originated 80–50 Mya. Two important clade origin events were detected. The first at 100–80 Mya, affected native and exotic species, and reflects a global diversification period at a time when the Mediterranean Sea did not yet exist. The second occurred during the last 50 Mya, and is noticeable among endemic and native species, but not among exotic species. This period corresponds to isolation of the Mediterranean from Indo-Pacific waters before the Messinian salinity crisis. The Mediterranean fish fauna illustrates well the assembly of regional faunas through origination and immigration, where dispersal and isolation have shaped the emergence of a biodiversity hotspot. PMID:22590545

  13. Miocene to Pleistocene osmium isotopic records of the Mediterranean sediments

    NASA Astrophysics Data System (ADS)

    Kuroda, Junichiro; Jiménez-Espejo, Francisco J.; Nozaki, Tatsuo; Gennari, Rocco; Lugli, Stefano; Manzi, Vinicio; Roveri, Marco; Flecker, Rachel; Sierro, Francisco J.; Yoshimura, Toshihiro; Suzuki, Katsuhiko; Ohkouchi, Naohiko

    2016-01-01

    In the late Miocene the Mediterranean Sea experienced a salinity crisis and thick sequences of evaporites precipitated across the deep and marginal basins. In this study we report Os isotopic records from Deep Sea Drilling Project and Ocean Drilling Project cores in the Mediterranean: the Balearic Sea (Site 372), the Tyrrhenian Sea (Site 654), the Ionian Basin (Site 374), and the Florence Rise (Sites 375-376), as well as Integrated Ocean Drilling Project Site U1387 in Gulf of Cadiz, North Atlantic. Pliocene-Pleistocene sediments at all sites show 187Os/188Os values close to that of the coeval ocean water, indicating that the Mediterranean was connected to the North Atlantic. Evaporitic sediments deposited during the latest Miocene, however, have 187Os/188Os values significantly lower than coeval ocean water values. The offset of the Mediterranean evaporite 187Os/188Os is attributed to limited exchange with the North Atlantic during the Messinian salinity crisis. The source of unradiogenic Os is likely to be weathering of ultramafic rocks (ophiolites) cropping out in the Mediterranean's drainage basins. Based on a box model we estimated the amount of unradiogenic Os and the Atlantic-Mediterranean exchange rate to explain this offset. Os isotopic ratios of the pre-evaporite sediments in the western Mediterranean are almost identical to that of the coeval ocean water. In contrast, equivalent sediments from the Florence Rise have significantly lower 187Os/188Os values. The offset in the Os isotopic ratio on the Florence Rise is attributed either to limited water exchange between eastern and western Mediterranean or to local effects associated with exhumation of the Troodos ophiolites (Cyprus).

  14. Bayesian Hierarchical Models to Augment the Mediterranean Ocean Forecast System

    DTIC Science & Technology

    2006-06-15

    vector. Conversely, in low wind speed events (e.g. see the Tyrrhenian Sea ), the wind direction is arbitrary as reflected in the distributions that span a...every other BHM prediction grid location (prediction grid resolution is 0.25◦) in the western basin of the Mediterranean Sea . A green vector within...winds do not influence the ECMWF analyses at the resolution of the oceanic mesoscale in the Mediterranean Sea (Milliff and Morzel, 2003). Conversely

  15. Circulation in the Southeastern Mediterranean Sea (EGITTO-NICOP)

    DTIC Science & Technology

    2007-09-30

    Circulation in the Southeastern Mediterranean Sea (EGITTO-NICOP) Pierre-Marie Poulain Istituto Nazionale di Oceanografia e di Geofisica...marine environmental evolution, with particular emphasis on the eddy dynamics in marginal seas where the effect of bottom morphology, the forcing by...variability in the southeastern Mediterranean waters using low-cost satellite-tracked drifters in concert with satellite observations of sea surface

  16. Bayesian Hierarchical Models to Augment the Mediterranean Forecast System

    DTIC Science & Technology

    2006-09-30

    case for SSH uncertainty. Relative minima in SST initial condition uncertainty occur east of Majorca, in the northern Tyrrhenian Sea , and in the...demonstrate forecast uncertainties during difficult to predict regime transitions in the Mediterranean Sea (e.g. the Fall transition, deep water formation...variance, or “spread” at each MFS-Wind-BHM output grid location in a blow-up of the western Mediterranean Sea , centered on the Gulf of Lions (Fig 1

  17. Climatic factors in resurgence of Mediterranean spotted fever

    SciTech Connect

    Arenas, E.E.; Creus, B.F.; Cueto, F.B.; Porta, F.S.

    1986-06-07

    There has been a recent resurgence of Mediterranean spotted fever in areas bordering the Mediterranean Sea. This disease is caused by Rickettsia conorii, the dog tick being the vector and main reservoir. Ticks prefer warm weather and their activity increases with rising temperature. In the Valles Occidental, Spain, the incidence of the disease is correlated with hotter and drier summers in the past ten years.

  18. The Mediterranean and Black Sea Fisheries at Risk from Overexploitation

    PubMed Central

    Tsikliras, Athanassios C.; Dinouli, Anny; Tsiros, Vasileios-Zikos; Tsalkou, Eleni

    2015-01-01

    The status of the Mediterranean and Black Sea fisheries was evaluated for the period 1970-2010 on a subarea basis, using various indicators including the temporal variability of total landings, the number of recorded stocks, the mean trophic level of the catch, the fishing-in-balance index and the catch-based method of stock classification. All indicators confirmed that the fisheries resources of the Mediterranean and Black Sea are at risk from overexploitation. The pattern of exploitation and the state of stocks differed among the western (W), central (C) and eastern (E) Mediterranean subareas and the Black Sea (BS), with the E Mediterranean and BS fisheries being in a worst shape. Indeed, in the E Mediterranean and the BS, total landings, mean trophic level of the catch and fishing-in-balance index were declining, the cumulative percentage of overexploited and collapsed stocks was higher, and the percentage of developing stocks was lower, compared to the W and C Mediterranean. Our results confirm the need for detailed and extensive stock assessments across species that will eventually lead to stocks recovering through conservation and management measures. PMID:25793975

  19. Cyclone contribution to the Mediterranean Sea water budget

    NASA Astrophysics Data System (ADS)

    Flaounas, E.; Di Luca, A.; Drobinski, P.; Mailler, S.; Arsouze, T.; Bastin, S.; Beranger, K.; Lebeaupin Brossier, C.

    2016-02-01

    This paper analyzes the impact of cyclones to the atmospheric components on the Mediterranean Sea Water Budget, namely the cyclones contribution to precipitation and evaporation over the Mediterranean Sea. Three regional simulations were performed with the WRF model for the period 1989-2008. The model was run (1) as a standalone model, (2) coupled with the oceanic model NEMO-MED12 and (3) forced by the smoothed Sea Surface Temperature (SST) fields from the second simulation. Cyclones were tracked in all simulations, and their contribution to the total rainfall and evaporation was quantified. Results show that cyclones are mainly associated with extreme precipitation, representing more than 50 % of the annual rainfall over the Mediterranean Sea. On the other hand, we found that cyclone-induced evaporation represents only a small fraction of the annual total, except in winter, when the most intense Mediterranean cyclones take place. Despite the significant contribution of cyclones to rainfall, our results show that there is a balance between cyclone-induced rainfall and evaporation, suggesting a weak net impact of cyclones on the Mediterranean Sea water budget. The sensitivity of our results with respect to rapid SST changes during the development of cyclones was also investigated. Both rainfall and evaporation are affected in correlation with the SST response to the atmosphere. In fact, air feedbacks to the Mediterranean Sea during the cyclones occurrence were shown to cool down the SST and consequently to reduce rainfall and evaporation at the proximity of cyclone centers.

  20. The Mediterranean and Black Sea fisheries at risk from overexploitation.

    PubMed

    Tsikliras, Athanassios C; Dinouli, Anny; Tsiros, Vasileios-Zikos; Tsalkou, Eleni

    2015-01-01

    The status of the Mediterranean and Black Sea fisheries was evaluated for the period 1970-2010 on a subarea basis, using various indicators including the temporal variability of total landings, the number of recorded stocks, the mean trophic level of the catch, the fishing-in-balance index and the catch-based method of stock classification. All indicators confirmed that the fisheries resources of the Mediterranean and Black Sea are at risk from overexploitation. The pattern of exploitation and the state of stocks differed among the western (W), central (C) and eastern (E) Mediterranean subareas and the Black Sea (BS), with the E Mediterranean and BS fisheries being in a worst shape. Indeed, in the E Mediterranean and the BS, total landings, mean trophic level of the catch and fishing-in-balance index were declining, the cumulative percentage of overexploited and collapsed stocks was higher, and the percentage of developing stocks was lower, compared to the W and C Mediterranean. Our results confirm the need for detailed and extensive stock assessments across species that will eventually lead to stocks recovering through conservation and management measures.

  1. TERENO-MED: Terrestrial Environmental Observatories in the Mediterranean Region

    NASA Astrophysics Data System (ADS)

    Krueger, Elisabeth; Friesen, Jan; Kallioras, Andreas; Bogena, Heye; Devaraju, Anusuriya; Vereecken, Harry; Teutsch, Georg

    2013-04-01

    The Mediterranean region is one of the most imperilled regions in the world concerning present and future water scarcity. The region is delicately positioned at the crossroads between East and West, interlinking Europe, Asia and Africa. Societal and economic changes causing population growth, industrialisation and urbanisation lead to significant increases in food, water and energy demand. Hence, natural resources, such as water and soils, as well as ecosystems are put under pressure and water availability and quality will be severely affected in the future. At the same time, climate and extreme event projections from climate models for the Mediterranean are, unlike for most regions worldwide, consistent in their trends based on various scenarios. This consistency in the model predictions shows that the Mediterranean will face some of the most severe increases in dryness worldwide (based on consecutive dry days and soil moisture), and indicate a decrease of up to 50 % in available water resources within the next 50-100 years. These developments are accentuated by the fact that in many of the Mediterranean countries, natural renewable water resources are fully exploited or over-exploited already today, mainly due to agricultural irrigation, but also touristic activities. At the same time, the Mediterranean region is a global hot spot of freshwater biodiversity, with a high proportion of endemic and endangered species. While trend projections for water availability and climate change derived from global studies are consistent, regional patterns and heterogeneities, as well as local adaptation measures will largely determine the functioning of societies and the health of ecosystems. However, a lack of environmental data prohibits the development of sustainable adaptation measures to water scarcity on a scientific basis. Building on the experiences gained in the national TERENO network, a Mediterranean observatory network will be set-up, coordinated by two Helmholtz

  2. Multi-Model approach to reconstruct the Mediterranean Freshwater Evolution

    NASA Astrophysics Data System (ADS)

    Simon, Dirk; Marzocchi, Alice; Flecker, Rachel; Lunt, Dan; Hilgen, Frits; Meijer, Paul

    2016-04-01

    Today the Mediterranean Sea is isolated from the global ocean by the Strait of Gibraltar. This restricted nature causes the Mediterranean basin to react more sensitively to climatic and tectonic related phenomena than the global ocean. Not just eustatic sea-level and regional river run-off, but also gateway tectonics and connectivity between sub-basins are leaving an enhanced fingerprint in its geological record. To understand its evolution, it is crucial to understand how these different effects are coupled. The Miocene-Pliocene sedimentary record of the Mediterranean shows alternations in composition and colour and has been astronomically tuned. Around the Miocene-Pliocene Boundary the most extreme changes occur in the Mediterranean Sea. About 6% of the salt in the global ocean deposited in the Mediterranean Region, forming an approximately 2 km thick salt layer, which is still present today. This extreme event is named the Messinian Salinity Crisis (MSC, 5.97-5.33 Ma). The gateway and climate evolution is not well constrained for this time, which makes it difficult to distinguish which of the above mentioned drivers might have triggered the MSC. We, therefore, decided to tackle this problem via a multi-model approach: (1) We calculate the Mediterranean freshwater evolution via 30 atmosphere-ocean-vegetation simulations (using HadCM3L), to which we fitted to a function, using a regression model. This allows us to directly relate the orbital curves to evaporation, precipitation and run off. The resulting freshwater evolution can be directly correlated to other sedimentary and proxy records in the late Miocene. (2) By feeding the new freshwater evolution curve into a box/budget model we can predict the salinity and strontium evolution of the Mediterranean for a certain Atlantic-Mediterranean gateway. (3) By comparing these results to the known salinity thresholds of gypsum and halite saturation of sea water, but also to the late Miocene Mediterranean strontium

  3. Observing Mean Annual Mediterranean Maquis Ecosystem Respiration

    NASA Astrophysics Data System (ADS)

    Marras, S.; Bellucco, V.; Mereu, S.; Sirca, C.; Spano, D.

    2014-12-01

    In semi arid ecosystems, extremely low Soil Water Content (SWC) values may limit ecosystem respiration (Reco) to the point of hiding the typical exponential response of respiration to temperature. This work is aimed to understand and model the Reco of an evergreen Mediterranean maquis ecosystem and to estimate the contribution of soil CO2 efflux to Reco. The selected site is located in the center of the Mediterranean sea in Sardinia (Italy). Mean annual precipitation is 588 mm and mean annual temperature is 15.9 °C. Vegetation cover is heterogeneous: 70% covered by shrubs and 30% of bare soil. Net Ecosystem Exchange (NEE) is monitored with an Eddy Covariance (EC) tower since April 2004. Soil collars were placed underneath the dominant species (Juniperus phoenicea and Pistacia lentiscus) and over the bare soil. Soil CO2 efflux was measured once a month since April 2012. Soil temperature and SWC were monitored continuously at 5 cm depth in 4 different positions close to the soil collars. Six years of EC measurements (2005-2010) and two years of soil CO2 efflux (2012-2013) measurements were analysed. Reco was estimated from the measured EC fluxes at night after filtering for adequate turbulence (u* > 1.5). Reco measurements were then binned into 1°C intervals and median values were first fitted using the Locally Estimated Scatterplot Smoothing (LOESS) method (to determine the dominant trend of the experimental curve) Reco shows an exponential increase with air and soil temperature, until SWC measured at 0.2 m depth remains above 19% vol. Secondly, the coefficients of the selected Lloyd and Taylor (1994) were estimated through the nonlinear least square (nls) method: Rref (ecosystem respiration rate at a reference temperature of 10 °C was equal to 1.65 μmol m-2 s-1 and E0 (activation energy parameter that determines the temperature sensitivity) was equal to 322.46. In addition, bare and drier soils show a reduced response of measured CO2 efflux to increasing

  4. Medclic: the Mediterranean in one click

    NASA Astrophysics Data System (ADS)

    Troupin, Charles; Frontera, Biel; Sebastián, Kristian; Pau Beltran, Joan; Krietemeyer, Andreas; Gómara, Sonia; Gomila, Mikel; Escudier, Romain; Juza, Mélanie; Mourre, Baptiste; Garau, Angels; Cañellas, Tomeu; Tintoré, Joaquín

    2016-04-01

    "Medclic: the Mediterranean in one click" is a research and dissemination project focused on the scientific, technological and societal approaches of the Balearic Islands Coastal Observing and Forecasting System ({SOCIB}{www.socib.es}) in a collaboration with "la Caixa" Foundation. SOCIB aims at research excellence and the development of technology which enables progress toward the sustainable management of coastal and marine environments, providing solutions to meet the needs of society. Medclic goes one step forward and has two main goals: at the scientific level, to advance in establishing and understanding the mesoscale variability at the regional scale and its interaction, and thus improving the characterisation of the "oceanic weather" in the Mediterranean; at the outreach level: to bring SOCIB and the new paradigm of multi-platform observation in real time closer to society, through scientific outreach. SOCIB Data Centre is the core of the new multi-platform and real time oceanography and is responsible for directing the different stages of data management, ranging from data acquisition to its distribution and visualization through web applications. The system implemented relies on open source solutions and provides data in line with international standards and conventions (INSPIRE, netCDF Climate and Forecast, ldots). In addition, the Data Centre has implemented a REST web service, called Data Discovery. This service allows data generated by SOCIB to be integrated into applications developed by the Data Centre itself or by third parties, as it is the case with Medclic. Relying on this data distribution, the new web Medclic, www.medclic.es, constitutes an interactive scientific and educational area of communication that contributes to the rapprochement of the general public with the new marine and coastal observing technologies. Thanks to the Medclic web, data coming from new observing technologies in oceanography are available in real time and in one clic

  5. Mediterranean diet, olive oil and cancer.

    PubMed

    Colomer, Ramón; Menéndez, Javier A

    2006-01-01

    Olive oil is an integral ingredient of the "Mediterranean diet" and accumulating evidence suggests that it may have a potential role in lowering the risk of several types of cancers. The mechanisms by which the cancer-preventing effects of olive oil can be performed, however, are not known. We recently hypothesized that a novel molecular explanation concerning the anti-cancer actions of olive oil may relate to the ability of its monounsaturated fatty acid (MUFA) oleic acid (OA; 18:1n-9) to specifically regulate cancer-related oncogenes. Supporting our hypothesis, exogenous supplementation of cultured breast cancer cells with physiological concentrations of OA was found to suppress the overexpression of HER2 (Her-2/neu, erbB-2), a well-characterized oncogene playing a key role in the etiology, progression and response to chemotherapy and endocrine therapy in approximately 20% of breast carcinomas. OA treatment was also found to synergistically enhance the efficacy of trastuzumab, a humanized monoclonal antibody binding with high affinity to the ectodomain (ECD) of the Her2-coded p185(HER2) oncoprotein. Moreover, OA exposure significantly diminished the proteolytic cleavage of the ECD of HER2 and, consequently, its activation status, a crucial molecular event that determines both the aggressive behavior and the response to trastuzumab of Her2-overexpressing breast carcinomas. Our most recent findings further reveal that OA exposure may suppresses HER2 at the transcriptional level by up-regulating the expression of the Ets protein PEA3 -a DNA-binding protein that specifically blocks HER2 promoter activity- in breast, ovarian and stomach cancer cell lines. This anti-HER2 property of OA offers a previously unrecognized molecular mechanism by which olive oil may regulate the malignant behavior of cancer cells. From a clinical perspective, it could provide an effective means of influencing the outcome of Her-2/neu-overexpressing human carcinomas with poor prognosis

  6. Circulation dynamics of Mediterranean precipitation variability 1948-98

    NASA Astrophysics Data System (ADS)

    Dünkeloh, A.; Jacobeit, J.

    2003-12-01

    Canonical correlation analysis is used to identify main coupled circulation-rainfall patterns and to relate recent variability and trends of Mediterranean precipitation to large-scale circulation dynamics. Analyses are based on geopotential heights (500 and 1000 hPa levels) for the North Atlantic-European area (National Centers for Environmental Prediction-National Center for Atmospheric Research reanalysis) and on highly resolved (0.5° × 0.5° ) monthly rainfall grids (Climatic Research Unit, Norwich) selected for the Mediterranean area during the 1948-98 period. Combining monthly analyses with similar characteristics to seasonal samples yields winter (October-March), spring (April-May) and summer (June-September) types of coupled variability; a particular autumn type for the whole Mediterranean does not occur on the monthly time scale. Coupled patterns specifically linked to one or two seasons include an east Atlantic jet (EA-Jet) related pattern for summer and a Mediterranean meridional circulation (MMC) pattern for winter and spring. The most important pattern recurring with dynamical adjustments throughout the whole year reflects the seasonal cycle of the Mediterranean oscillation (MO), which is linked (with seasonal dependence) to the Northern Hemisphere teleconnection modes of the Arctic oscillation (AO) and North Atlantic oscillation (NAO). Winter rainfall trends of the recent decades marked by widespread decreases in the Mediterranean area and by opposite conditions in the southeastern part are linked to particular changes over time in several of the associated circulation patterns. Thus, different regional rainfall changes are integrated into an overall interrelation between Mediterranean rainfall patterns and large-scale atmospheric circulation dynamics.

  7. Environmental Changes in the pre-Messinian Mediterranean Region

    NASA Astrophysics Data System (ADS)

    Mayser, J. P.; Marzocchi, A.; Lunt, D. J.; Pancost, R. D.; Sierro, F. J.; Flecker, R.

    2015-12-01

    The Messinian Salinity Crisis (MSC) is an extreme event which occurred in the Mediterranean Basin at the end of the Miocene (5.97 to 5.33 Ma) resulting in thick evaporite deposits. There is evidence of restriction of the Atlantic-Mediterranean corridor several million years before the first evaporites. These pre-MSC successions are dominated by precession-controlled lithological variations which are putative responses to changing fluvial runoff. Recent climate simulations indicate that runoff into the Eastern Mediterranean is influenced by monsoonal precipitation from the North African continent. The Sorbas Basin in Spain and the Pissouri Section on Cyprus both contain pre-MSC successions from the margins of the Mediterranean Basin. We analysed biomarkers in conjunction with existing faunal records to understand whether simulated runoff changes were manifested in the sedimentological record and organic matter assemblages. This multi-proxy dataset allows us to compare the environmental evolution of the western vs. eastern basins prior to the MSC and allows us to test both climate models for Messinian climate variabitly and conceptual models for sedimentation. In the Sorbas Basin, pronounced orbital changes in faunal assemblages reflect Mediterrannean influences into the local Sorbas system; however, these are not manifested in biomarker assemblages, which are likely governed by more local hydrological processes, which in the Western Mediterranean lacked a strong precessional control. In the Pissouri Basin, however, terrigeous OM inputs sources exhibit strong orbital variations, suggesting a close link to precessionally driven changes in rainfall. Together, these results validate the sapropel formation hypothesis in the Mediterranean and confirm a strong precessional control on the African monsoon during the late Miocene; however, they also reveal the complex controls on the hydrology and sedimentology of marginal Mediterranean basins, such as the Sorbas Basin.

  8. Setting Priorities for Regional Conservation Planning in the Mediterranean Sea

    PubMed Central

    Micheli, Fiorenza; Levin, Noam; Giakoumi, Sylvaine; Katsanevakis, Stelios; Abdulla, Ameer; Coll, Marta; Fraschetti, Simonetta; Kark, Salit; Koutsoubas, Drosos; Mackelworth, Peter; Maiorano, Luigi; Possingham, Hugh P.

    2013-01-01

    Spatial prioritization in conservation is required to direct limited resources to where actions are most urgently needed and most likely to produce effective conservation outcomes. In an effort to advance the protection of a highly threatened hotspot of marine biodiversity, the Mediterranean Sea, multiple spatial conservation plans have been developed in recent years. Here, we review and integrate these different plans with the goal of identifying priority conservation areas that represent the current consensus among the different initiatives. A review of six existing and twelve proposed conservation initiatives highlights gaps in conservation and management planning, particularly within the southern and eastern regions of the Mediterranean and for offshore and deep sea habitats. The eighteen initiatives vary substantially in their extent (covering 0.1–58.5% of the Mediterranean Sea) and in the location of additional proposed conservation and management areas. Differences in the criteria, approaches and data used explain such variation. Despite the diversity among proposals, our analyses identified ten areas, encompassing 10% of the Mediterranean Sea, that are consistently identified among the existing proposals, with an additional 10% selected by at least five proposals. These areas represent top priorities for immediate conservation action. Despite the plethora of initiatives, major challenges face Mediterranean biodiversity and conservation. These include the need for spatial prioritization within a comprehensive framework for regional conservation planning, the acquisition of additional information from data-poor areas, species or habitats, and addressing the challenges of establishing transboundary governance and collaboration in socially, culturally and politically complex conditions. Collective prioritised action, not new conservation plans, is needed for the north, western, and high seas of the Mediterranean, while developing initial information

  9. Setting priorities for regional conservation planning in the Mediterranean Sea.

    PubMed

    Micheli, Fiorenza; Levin, Noam; Giakoumi, Sylvaine; Katsanevakis, Stelios; Abdulla, Ameer; Coll, Marta; Fraschetti, Simonetta; Kark, Salit; Koutsoubas, Drosos; Mackelworth, Peter; Maiorano, Luigi; Possingham, Hugh P

    2013-01-01

    Spatial prioritization in conservation is required to direct limited resources to where actions are most urgently needed and most likely to produce effective conservation outcomes. In an effort to advance the protection of a highly threatened hotspot of marine biodiversity, the Mediterranean Sea, multiple spatial conservation plans have been developed in recent years. Here, we review and integrate these different plans with the goal of identifying priority conservation areas that represent the current consensus among the different initiatives. A review of six existing and twelve proposed conservation initiatives highlights gaps in conservation and management planning, particularly within the southern and eastern regions of the Mediterranean and for offshore and deep sea habitats. The eighteen initiatives vary substantially in their extent (covering 0.1-58.5% of the Mediterranean Sea) and in the location of additional proposed conservation and management areas. Differences in the criteria, approaches and data used explain such variation. Despite the diversity among proposals, our analyses identified ten areas, encompassing 10% of the Mediterranean Sea, that are consistently identified among the existing proposals, with an additional 10% selected by at least five proposals. These areas represent top priorities for immediate conservation action. Despite the plethora of initiatives, major challenges face Mediterranean biodiversity and conservation. These include the need for spatial prioritization within a comprehensive framework for regional conservation planning, the acquisition of additional information from data-poor areas, species or habitats, and addressing the challenges of establishing transboundary governance and collaboration in socially, culturally and politically complex conditions. Collective prioritised action, not new conservation plans, is needed for the north, western, and high seas of the Mediterranean, while developing initial information-based plans

  10. Mediterranean Diet and Cardiodiabesity: A Review

    PubMed Central

    García-Fernández, Elena; Rico-Cabanas, Laura; Rosgaard, Nanna; Estruch, Ramón; Bach-Faig, Anna

    2014-01-01

    Cardiodiabesity has been used to define and describe the well-known relationship between type 2 Diabetes Mellitus (T2DM), obesity, the metabolic syndrome (MetS) and cardiovascular disease (CVD). The objective of this study was to perform a scientific literature review with a systematic search to examine all the cardiovascular risk factors combined and their relationship with adherence to the Mediterranean Diet (MedDiet) pattern as primary prevention against cardiodiabesity in a holistic approach. Research was conducted using the PubMed database including clinical trials, cross-sectional and prospective cohort studies. Thirty-seven studies were reviewed: fourteen related to obesity, ten to CVD, nine to MetS, and four to T2DM. Indeed 33 provided strong evidence on the association between adherence to a MedDiet and a reduced incidence of collective cardiodiabesity risk in epidemiological studies. This scientific evidence makes the MedDiet pattern very useful for preventive strategies directed at the general population and also highlights the need to consider all these diet-related risk factors and health outcomes together in daily primary care. PMID:25192027

  11. Endemic strongyloidiasis on the Spanish Mediterranean coast.

    PubMed

    Sánchez, P R; Guzman, A P; Guillen, S M; Adell, R I; Estruch, A M; Gonzalo, I N; Olmos, C R

    2001-07-01

    Diagnosis and treatment of Strongyloides stercoralis infection can be difficult, and a high degree of clinical suspicion in patients who have visited an endemic area is required. We describe the epidemiology and clinical features of 152 prospectively identified cases of strongyloidiasis in an European region, and identify risk factors for the development of severe forms of the disease. This was a prospective study of all patients admitted to a single institution over an 8-year period. Patients (n=152) were mainly elderly male farmers (79%) who had acquired the disease by working barefoot in contact with soil and ingesting non-drinking water. Eosinophilia was a sensitive marker for the infection (82%). Twenty patients (13%) developed severe forms of the illness and six patients (4%) died. A significant association was found between severe forms of strongyloidiasis and steroid usage (OR 9.0, 95%CI 2.1-37.6), immunodebilitating illness (OR 10.1, 95%CI 3.2-32.3) and other immunosuppressive therapy (OR 13.7, 95%CI 2.9-58.7), but by logistic regression analysis, only immunodebilitating disease was as a risk factor (OR 2.1, 95%CI 1.78-2.43). S. stercolaris infection is endemic in the Spanish Mediterranean coast. The frequent development of severe forms of the disease, with a high mortality, makes early recognition and treatment essential.

  12. Lightning activity and aerosols over the Mediterranean

    NASA Astrophysics Data System (ADS)

    Proestakis, Emmanouil; Kazadzis, Stelios; Kotroni, Vassiliki; Lagouvardos, Kostas; Kazantzidis, Andreas

    2015-04-01

    Lightning activity has received extended scientific attention over the past decades. Several international studies on lightning activity and initiation mechanisms have related the increased aerosol concentrations to lightning enhancement. In the frame of TALOS project, we investigated the effect of aerosols on lightning activity over the Mediterranean Sea. Cloud to ground lightning activity data from ZEUS lightning detection network operated and maintained by the National Observatory of Athens, were used along with atmospheric optical depth (AOD) data retrieved by MODIS, on board Aqua satellite. The analysis covers a period of nine years, spanning from 2005 up to 2013. The results show the importance of aerosols in lightning initiation and enhancement. It is shown that the mean AOD of the days with lightning activity per season is larger than the mean seasonal AOD in 90% of the under study domain. Furthermore, lightning activity increase with increasing aerosol loading was found to be more pronounced during summertime and for atmospheric optical depth values up to 0.4. Additionally, during summertime, the spatial analysis showed that the percentage of days with lightning activity is increasing with increasing aerosol loading. Finally, time series for the period 2005-2013 of the days with lightning activity and AOD differences showed similar temporal behavior. Overall, both the spatial and temporal analysis showed that lightning activity is correlated to aerosol loading and that this characteristic is consistent for all seasons.

  13. Potential vorticity patterns in Mediterranean hurricanes

    NASA Astrophysics Data System (ADS)

    Laviola, Sante; Marcello Miglietta, M.; Cerrai, Diego; Cattani, Elsa; Levizzani, Vincenzo

    2016-04-01

    Two new variables have been introduced to better identify the potential vorticity (PV) anomalies due to the intrusion of dry stratospheric air from those induced by the diabatic latent heating. This new approach has been applied to the analysis of three Mediterranean tropical-like cyclones characterized by heavy precipitation patterns. Model simulations show that the interaction between an upper level PV streamer, located on the left exit of a jet stream and a middle-low level PV anomaly, induced by the convection development around the low level vortex, plays a key role in the intensification of cyclones in all cases. These anomalies, despite their strong mutual interaction, do not form a fully developed PV tower. In the mature stage, the shape of the upper level PV anomaly around the cyclone is different for each case and appears somehow dependent on the lifetime of the vortex. A first comparison with satellite-derived products seems to confirm the initial results from model simulations.

  14. Index medicus for the Eastern Mediterranean region

    PubMed Central

    Al-Shorbaji, Najeeb

    2008-01-01

    The study provides the rationale, history and current status of the Index Medicus for the World Health Organization Eastern Mediterranean Region. The Index is unique in combining the geographic coverage of peer-reviewed health and biomedical journals (408 titles) from the 22 countries of the Region. Compiling and publishing the Index coupled with a document delivery service is an integral part of the WHO Regional Office's knowledge management and sharing programme. In this paper, bibliometric indicators are presented to demonstrate the distribution of journals, articles, languages, subjects and authors as well as availability in printed and electronic formats. Two countries in the Region (Egypt and Pakistan) contribute over 50% of the articles in the Index. About 90% of the articles are published in English. Epidemiology articles represent 8% of the entire Index. 15% of the journals in the Index are also indexed in MEDLINE, while 7% are indexed in EMBASE. Future developments of the Index will include covering more journals and adding other types of health and biomedical literature, including reports, theses, books and current research. The challenges and lessons learnt are discussed. PMID:18826568

  15. View of Mediterranean coast of France

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A vertical view of the Mediterranean coast of France is seen in this Skylab 3 Earth Resources Experiments Package S190-B (five-inch earth terrain camera) photograph taken from the Skylab space station in Earth orbit. This view includes the port cities of Marseilles (near center) and Toulon (far right). The mouth of the Rhone River is on the left. The irregular L-shaped inland body of water is Etang de Berre and is connected to the sea by a narrow canal. The city of Martiques is on the inland side of the canal. Cloud formations form narrow bands or streets along the coast east of Martiques and over the water. Cultural features such as major highways are indicated by thin white lines. Harbor facilities (wharves) and inner city patterns are distinctive in Marseilles and Toulon. The light tan areas in the regions inland from the major cities represent farming communities. The patterns are well shown in the vicinity of the Rhone River. The geology of the region is complex as illustrated by

  16. Eddy generation in the Mediterranean undercurrent

    NASA Astrophysics Data System (ADS)

    Serra, Nuno; Ambar, Isabel

    In the framework of the European Union MAST III project Canary Islands Gibraltar Azores Observations, 24 RAFOS floats were deployed in the Mediterranean Water (MW) undercurrent off south Portugal between September 1997 and September 1998. A preliminary analysis of this Lagrangian approach, complemented with XBT and current-meter data, show some of the major aspects of the flow associated with the undercurrent as well as associated eddy activity. Floats that stayed in the undercurrent featured a downstream deceleration and a steering by bottom topography. Three meddy formations at Cape St. Vincent could be isolated from the float data. The dynamical coupling of meddies and cyclones was observed for a considerable period of time. The generation of two dipolar structures in the Portimão Canyon region also was observed with the float data. A major bathymetric relief—Gorringe Bank—was not only an important constraint to the eddy trajectories and of the flow at the MW levels but also a site for meddy formation.

  17. Architectural plasticity in a Mediterranean winter annual.

    PubMed

    Shemesh, Hagai; Zaitchik, Benjamin; Acuña, Tania; Novoplansky, Ariel

    2012-04-01

    Size variability in plants may be underlain by overlooked components of architectural plasticity. In annual plants, organ sizes are expected to depend on the availability and reliability of resources and developmental time. Given sufficient resources and developmental time, plants are expected to develop a greater number of large branches, which would maximize fitness in the long run. However, under restrictive growth conditions and environmental reliability, developing large branches might be risky and smaller branches are expected to foster higher final fitness. Growth and architecture of Trifolium purpureum (Papilionaceae) plants from both Mediterranean (MED) and semi-arid (SAR) origins were studied, when plants were subjected to variable water availability, photoperiod cues and germination timing. Although no clear architectural plasticity could be found in response to water availability, plants subjected to photoperiod cuing typical to late spring developed fewer basal branches. Furthermore, plants that germinated late were significantly smaller, with fewer basal branches, compared with plants which grew for the same time, starting at the beginning of the growing season. The results demonstrate an intricate interplay between size and architectural plasticities, whereby size modifications are readily induced by environmental factors related to prevalent resource availability but architectural plasticity is only elicited following the perception of reliable anticipatory cues.

  18. Recent nutrient dynamics in the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Lee, Kitack; Moon, Ji-Young

    2016-04-01

    The concentrations of nitrate (N) and phosphate (P), and the N:P ratio in the upper water column of the Mediterranean Sea (MED) were examined using observational data (~173,000 data points) collected since 1980s. The observed trends were found to distinctly evolve in the western and eastern MED. In the western MED the N and P concentrations have rapidly increased over time and was broadly consistent with the riverine input history from the populated areas surrounding the western MED. Contrarily, the N and P concentrations in the eastern MED markedly increased up until the mid-1995 and briefly remained high between 1995 and 2000. The N concentration rapidly decreased thereafter. In particular, the three-phase temporal transition of N and P in the eastern MED (increase-constant-decline) was more consistent with the emission history of pollutant nitrogen from the western European continent, in which regulation of emissions of pollutant nitrogen has been in place since 1970s. Our analysis implies that the recent N dynamics in the upper MED appeared to be sensitive to input dynamics of anthropogenic N, via atmospheric deposition and river. This conclusion is further strengthened by good agreement between the integrated rate of increase in the upper-water N inventory and the total anthropogenic N input during the past 30 years.

  19. Study of the impact of cyclogenesis at the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Ribo, M.; Llasat, C.

    2009-09-01

    The Mediterranean Basin is usually affected by high impact weather events, generating high impacts in all Mediterranean countries and causing important damages. This basin is surrounded by mountains and arid regions, and the interaction of the air flow with the orography barriers produces many effects, the most important is the formation of low pressure centers. This is one of the reasons why the Mediterranean Sea is considered to be the most cyclogenetic area in the world (Jansà, 1997). Floods are also one of the most important natural hazards in the Mediterranean Basin. Flood events occur when soil absorption, runoff or drainage cannot adequately disperse intense rainfall from quasi-stationary or stationary weather systems in short time periods. In some occasions these floods produce high social impact in the affected areas. Our work presents the study of the relationship between the flood episodes and the presence of cyclones in the Mediterranean Basin during those episodes, between 1990 and 2004. Information about social impact of each event has also been considered. To do these analyses the MEDEX database (MEDiterranean EXperiment on cyclones that produce high impact weather in the Mediterranean) has been improved in the frame work of the European FLASH project, and information about cyclones and rainfall has been extracted from the MEDEX cyclones database. A total of 217 flood events had been identified. Once the presence of one or more cyclones during each flood episode has been identified, temporal and regional analyses were made to determine the distribution of the cyclonic centers and to study the evolution of the events. Mediterranean cyclogenesis is leaded by influence of external systems (along the African coast, from the Atlantic Ocean, and from the west of Europe), although the majority of the cyclones (87% of the studied cases) are generated in the Mediterranean Basin, under influence of preexistent systems. There are different Mediterranean

  20. Clastic depositional styles and reservoir potential of Mediterranean basins

    SciTech Connect

    Bouma, A.H. )

    1990-05-01

    A variety of tectonic styles and activities throughout the late Mesozoic and younger epochs influenced sediment transport to the Mediterranean basins and, consequently, the approach needed to finding reservoir-type clastics. The style of the present-day basins varies from west to east, with large basinal depressions and continental rises in the western province, more elongate shapes in the central area, and numerous small basins and trenches in the eastern Mediterranean. In general terms, all these basins contain a similar fill: a deep-water sequence older than late Miocene, overlain by upper Miocene evaporites, and topped by Pliocene-Quaternary clastics. The exact type of fill depends on several factors, including proximity to the sediment source, climatic conditions, subsidence and tectonic activity, and tectono-eustatic or glacio-eustatic oscillations. Investigations on many of the clastic reservoirs in Mediterranean basins should emphasize submarine fans. The modern Mediterranean Sea contains several mid-sized fans (Rhone, Ebro, Valencia, and Nile fans) and many small ones (e.g., Crati Fan). There are several well-studied Tertiary subsurface and outcropping turbidite systems. The concept of deep-water marine sands, and many of the initial studies, began with some of the now classic outcrops in Italy, France, and Spain. A well-integrated study of both modern and ancient turbidite series is needed to construct basic exploration models for the Mediterranean region. 9 figs., 1 tab.

  1. Syndrome-driven diversification in a Mediterranean ecosystem.

    PubMed

    Verdú, Miguel; Pausas, Juli G

    2013-06-01

    Phylogenetic methods to detect lineage diversification have been traditionally used within a particular taxonomic clade, but rarely applied to detect local diversification. For understanding in situ diversification triggered by novel conditions it is necessary to focus on the time slice where such conditions occur. These new conditions may differentially affect the diversification rate of lineages with different morpho-functional syndromes. A prominent example of these processes occurs in the Mediterranean Basin, where climate arising along the Tertiary/Quaternary transition acted as an environmental filter. In this context, lineages with different syndromes (sclerophyllous and nonsclerophyllous) are hypothesized to have different local diversification rates after the rise of the Mediterranean conditions. We used macroevolutionary methods of time-dependent diversification on a calibrated local phylogeny accommodating topological and chronological uncertainty to test syndrome-driven diversification in Mediterranean shrublands from the eastern Iberian Peninsula. We found phylogenetic evidence of higher speciation associated with the nonsclerophyllous syndrome, although extinction rates were similar between syndromes. Consequently a syndrome-driven local diversification has occurred in shrublands under Mediterranean conditions. The results provide an example of how the integration of the environmental filter in a dated phylogeny may recreate the local history of lineages and help to explain assembly processes in Mediterranean ecosystems.

  2. Evaluation of Rainfall-Runoff Models for Mediterranean Subcatchments

    NASA Astrophysics Data System (ADS)

    Cilek, A.; Berberoglu, S.; Donmez, C.

    2016-06-01

    The development and the application of rainfall-runoff models have been a corner-stone of hydrological research for many decades. The amount of rainfall and its intensity and variability control the generation of runoff and the erosional processes operating at different scales. These interactions can be greatly variable in Mediterranean catchments with marked hydrological fluctuations. The aim of the study was to evaluate the performance of rainfall-runoff model, for rainfall-runoff simulation in a Mediterranean subcatchment. The Pan-European Soil Erosion Risk Assessment (PESERA), a simplified hydrological process-based approach, was used in this study to combine hydrological surface runoff factors. In total 128 input layers derived from data set includes; climate, topography, land use, crop type, planting date, and soil characteristics, are required to run the model. Initial ground cover was estimated from the Landsat ETM data provided by ESA. This hydrological model was evaluated in terms of their performance in Goksu River Watershed, Turkey. It is located at the Central Eastern Mediterranean Basin of Turkey. The area is approximately 2000 km2. The landscape is dominated by bare ground, agricultural and forests. The average annual rainfall is 636.4mm. This study has a significant importance to evaluate different model performances in a complex Mediterranean basin. The results provided comprehensive insight including advantages and limitations of modelling approaches in the Mediterranean environment.

  3. [Origin, components and mechanisms of action of the Mediterranean diet].

    PubMed

    Urquiaga, Inés; Echeverría, Guadalupe; Dussaillant, Catalina; Rigotti, Attilio

    2017-01-01

    The Mediterranean diet is currently considered a healthy dietary pattern. It includes a great variety of foods, which are eaten in moderation and within a positive social environment. The generic term "Mediterranean diet" was born after the "Seven Countries Study" led by Ancel Keys around 1960. This dietary pattern is characterized by a high intake of fruits and vegetables, whole grains, legumes, nuts, fish, white meats and olive oil. It also includes moderate consumption of fermented dairy products, low intake of red meat and drinking wine with moderation during meals. Nutritionally, this diet is low in saturated fats and animal protein, high in antioxidants, fiber and monounsaturated fats, and exhibits an adequate omega-6/omega-3 fatty acid balance. The main bioactive compounds, which explain the health benefits of this dietary pattern, are antioxidants, fiber, monounsaturated and omega-3 fatty acids, phytosterols and probiotics. This diet is not exclusively confined to the Mediterranean Basin. Central Chile has a Mediterranean climate and our agriculture and culinary traditions are similar to those found in Mediterranean countries. Therefore, it is fundamental to increase awareness about the richness of our natural produce as well as our culinary culture, which may bring many health benefits and improve the quality of life in our population.

  4. Discrimination of common Mediterranean plant species using field spectroradiometry

    NASA Astrophysics Data System (ADS)

    Manevski, Kiril; Manakos, Ioannis; Petropoulos, George P.; Kalaitzidis, Chariton

    2011-12-01

    Field spectroradiometry of land surface objects supports remote sensing analysis, facilitates the discrimination of vegetation species, and enhances the mapping efficiency. Especially in the Mediterranean, spectral discrimination of common vegetation types, such as phrygana and maquis species, remains a challenge. Both phrygana and maquis may be used as a direct indicator for grazing management, fire history and severity, and the state of the wider ecosystem equilibrium. This study aims to investigate the capability of field spectroradiometry supporting remote sensing analysis of the land cover of a characteristic Mediterranean area. Five common Mediterranean maquis and phrygana species were examined. Spectra acquisition was performed during an intensive field campaign deployed in spring 2010, supported by a novel platform MUFSPEM@MED (Mobile Unit for Field SPEctral Measurements at the MEDiterranean) for high canopy measurements. Parametric and non-parametric statistical tests have been applied to the continuum-removed reflectance of the species in the visible to shortwave infrared spectral range. Interpretation of the results indicated distinct discrimination between the studied species at specific spectral regions. Statistically significant wavelengths were principally found in both the visible and the near infrared regions of the electromagnetic spectrum. Spectral bands in the shortwave infrared demonstrated significant discrimination features for the examined species adapted to Mediterranean drought. All in all, results confirmed the prospect for a more accurate mapping of the species spatial distribution using remote sensing imagery coupled with in situ spectral information.

  5. Climate change in Mediterranean mountains during the 21st century.

    PubMed

    Nogués Bravo, David; Araújo, Miguel B; Lasanta, Teodoro; López Moreno, Juan Ignacio

    2008-06-01

    Mediterranean mountain biomes are considered endangered due to climate change that affects directly or indirectly different key features (biodiversity, snow cover, glaciers, run-off processes, and water availability). Here, we provide an assessment of temperature, precipitation, and spring precipitation changes in Mediterranean mountains under different emission scenarios (Special Report on Emission Scenarios) and Atmosphere-Ocean-Coupled General Circulation Models for two periods: 2055 (2040-2069 period) and 2085 (2070-2099). Finally, the future climate trends projected for Mediterranean mountains are compared with those trends projected for non-Mediterranean European mountain ranges. The range of projected warming varies between +1.4 degrees C and 5.1 degrees C for 2055 (+1.6 degrees C and +8.3 degrees C for 2085). Climate models also project a reduction of precipitation, mainly during spring (-17% under Alfi and -4.8% under B1 for 2085). On the contrary, non-Mediterranean European mountains will n