Sample records for sea anemones cnidaria

  1. Sea anemones (Cnidaria: Anthozoa: Actiniaria) of Moreton Bay

    E-print Network

    Fautin, Daphne

    Sea anemones (Cnidaria: Anthozoa: Actiniaria) of Moreton Bay Daphne G. FAUTIN Department of Ecology.qm.qld.gov.au 35 Citation: Fautin, D.G., Crowther, A.L. & Wallace, C.C., 2008 12 01. Sea anemones (Cnidaria

  2. Distribution of sea anemones (Cnidaria, Actiniaria) in Korea analyzed by environmental clustering

    E-print Network

    Fautin, Daphne

    Distribution of sea anemones (Cnidaria, Actiniaria) in Korea analyzed by environmental clustering on Cnidaria and Ctenophora. Ó 2004 Kluwer Academic Publishers. Printed in the Netherlands. 497 #12;intertidal

  3. Formation of the Apical Flaps in Nematocysts of Sea Anemones (Cnidaria: Actiniaria)

    E-print Network

    Fautin, Daphne

    Formation of the Apical Flaps in Nematocysts of Sea Anemones (Cnidaria: Actiniaria) ABIGAIL J. REFT of the phylum Cnidaria (e.g., jellyfish, sea anemones, corals). Nematocysts are used in capture of prey, defense

  4. Sea Anemone (Cnidaria, Anthozoa, Actiniaria) Toxins: An Overview

    PubMed Central

    Frazão, Bárbara; Vasconcelos, Vitor; Antunes, Agostinho

    2012-01-01

    The Cnidaria phylum includes organisms that are among the most venomous animals. The Anthozoa class includes sea anemones, hard corals, soft corals and sea pens. The composition of cnidarian venoms is not known in detail, but they appear to contain a variety of compounds. Currently around 250 of those compounds have been identified (peptides, proteins, enzymes and proteinase inhibitors) and non-proteinaceous substances (purines, quaternary ammonium compounds, biogenic amines and betaines), but very few genes encoding toxins were described and only a few related protein three-dimensional structures are available. Toxins are used for prey acquisition, but also to deter potential predators (with neurotoxicity and cardiotoxicity effects) and even to fight territorial disputes. Cnidaria toxins have been identified on the nematocysts located on the tentacles, acrorhagi and acontia, and in the mucous coat that covers the animal body. Sea anemone toxins comprise mainly proteins and peptides that are cytolytic or neurotoxic with its potency varying with the structure and site of action and are efficient in targeting different animals, such as insects, crustaceans and vertebrates. Sea anemones toxins include voltage-gated Na+ and K+ channels toxins, acid-sensing ion channel toxins, Cytolysins, toxins with Kunitz-type protease inhibitors activity and toxins with Phospholipase A2 activity. In this review we assessed the phylogentic relationships of sea anemone toxins, characterized such toxins, the genes encoding them and the toxins three-dimensional structures, further providing a state-of-the-art description of the procedures involved in the isolation and purification of bioactive toxins. PMID:23015776

  5. Latitudinal Diversity of Sea Anemones (Cnidaria: Actiniaria)

    E-print Network

    Fautin, Daphne

    on terrestrial plants and animals. We plotted the empirical distribution of species occurrences in 10° bands anemone species resembles that of planktonic foraminiferans and benthic marine algae, although planktonic, and planktonic members only were inventoried by Fuhrman et al. (2008) for bacteria, and Rutherford et al. (1999

  6. Investigating the origins of triploblasty: `mesodermal' gene expression in a diploblastic animal, the sea anemone Nematostella vectensis (phylum, Cnidaria; class, Anthozoa)

    Microsoft Academic Search

    Mark Q. Martindale; Kevin Pang; John R. Finnerty

    2004-01-01

    Mesoderm played a crucial role in the radiation of the triploblastic Bilateria, permitting the evolution of larger and more complex body plans than in the diploblastic, non- bilaterian animals. The sea anemone Nematostella is a non- bilaterian animal, a member of the phylum Cnidaria. The phylum Cnidaria (sea anemones, corals, hydras and jellyfish) is the likely sister group of the

  7. Environmental sensing and response genes in Cnidaria: the chemical defensome in the sea anemone Nematostella vectensis

    PubMed Central

    Goldstone, J.V.

    2010-01-01

    The starlet sea anemone Nematostella vectensis has been recently established as a new model system for the study of the evolution of developmental processes, as cnidaria occupy a key evolutionary position at the base of the bilateria. Cnidaria play important roles in estuarine and reef communities, but are exposed to many environmental stressors. Here I describe the genetic components of a ‘chemical defensome’ in the genome of N. vectensis, and review cnidarian molecular toxicology. Gene families that defend against chemical stressors and the transcription factors that regulate these genes have been termed a ‘chemical defensome,’ and include the cytochromes P450 and other oxidases, various conjugating enyzymes, the ATP-dependent efflux transporters, oxidative detoxification proteins, as well as various transcription factors. These genes account for about 1% (266/27200) of the predicted genes in the sea anemone genome, similar to the proportion observed in tunicates and humans, but lower than that observed in sea urchins. While there are comparable numbers of stress-response genes, the stress sensor genes appear to be reduced in N. vectensis relative to many model protostomes and deuterostomes. Cnidarian toxicology is understudied, especially given the important ecological roles of many cnidarian species. New genomic resources should stimulate the study of chemical stress sensing and response mechanisms in cnidaria, and allow us to further illuminate the evolution of chemical defense gene networks. PMID:18956243

  8. Sea anemones (Cnidaria: Actiniaria) of the Faroe Islands: a preliminary list and biogeographic context

    E-print Network

    Fautin, Daphne G.; Daly, Marymegan; Cappola, Valerie A.

    2005-01-01

    We have identified 20 species of sea anemones (order Actiniaria) from BIOFAR material, eight of them new records for the Faroe Islands. This brings the total number of anemone species known thus far from the Faroes to 30. ...

  9. Distribution of sea anemones (Cnidaria, Actiniaria) in Korea analyzed by environmental clustering

    USGS Publications Warehouse

    Cha, H.-R.; Buddemeier, R.W.; Fautin, D.G.; Sandhei, P.

    2004-01-01

    Using environmental data and the geospatial clustering tools LOICZView and DISCO, we empirically tested the postulated existence and boundaries of four biogeographic regions in the southern part of the Korean peninsula. Environmental variables used included wind speed, sea surface temperature (SST), salinity, tidal amplitude, and the chlorophyll spectral signal. Our analysis confirmed the existence of four biogeographic regions, but the details of the borders between them differ from those previously postulated. Specimen-level distribution records of intertidal sea anemones were mapped; their distribution relative to the environmental data supported the importance of the environmental parameters we selected in defining suitable habitats. From the geographic coincidence between anemone distribution and the clusters based on environmental variables, we infer that geospatial clustering has the power to delimit ranges for marine organisms within relatively small geographical areas.

  10. Population structure and genetic variation in two tropical sea anemones (Cnidaria, Actinidae) with different reproductive strategies

    Microsoft Academic Search

    C. A. M. Russo; A. M. Solé-Cava; J. P. Thorpe

    1994-01-01

    Genetic variation and population structure of two tropical sea anemones, Bunodosoma caissarum Correa and Actinia bermudensis McMurrich were related to their different dispersal capabilities and reproductive modes. B. caissarum reproduces sexually and has a long-lived planktotrophic larva; A. bermudensis can reproduce both sexually and asexually, supposedly with short-range dispersal. Both species were sampled along 1150 km of Brazilian coastline between

  11. The Mitochondrial Genome of the Sea Anemone Metridium senile (Cnidaria): Introns, a Paucity of tRNA Genes, and a Near-Standard Genetic Code

    Microsoft Academic Search

    C. Timothy Beagley; Ronald Okimoto; David R. Wolstenholme

    The circular, 17,443 nucleotide-pair mitochondrial (mt) DNA molecule of the sea anemone, Metridium senile (class Anthozoa, phylum Cnidaria) is presented. This molecule contains genes for 13 energy pathway proteins and two ribosomal (r) RNAs but, relative to other metazoan mtDNAs, has two unique features: only two transfer RNAs (tRNA f-Met and tRNA Trp ) are encoded, and the cytochrome c

  12. Edwardsia sojabio sp. n. (Cnidaria: Anthozoa: Actiniaria: Edwardsiidae), a new abyssal sea anemone from the Sea ofJapan

    NASA Astrophysics Data System (ADS)

    Sanamyan, Nadya; Sanamyan, Karen

    2013-02-01

    The paper describes new deep-water edwardsiid sea anemone Edwardsia sojabio sp. n. which is very common on soft muddy bottoms at lower bathyal and upper abyssal depths in the Sea of Japan. It was recorded in high quantity in depths between 2545 and 3550 m and is the second abyssal species of the genus Edwardsia.

  13. Biological and population-genetic aspects of the sea anemone Actinia equina (Cnidaria: Anthozoa) along the Mediterranean coast of Israel

    Microsoft Academic Search

    O. Chomsky; J. Douek; N. E. Chadwick; Z. Dubinsky; B. Rinkevich

    2009-01-01

    The population genetics of most cnidarians remain poorly understood, in part due to the complexities of their modes of reproduction and hybridization among closely related species. Actiniaequina is the most common species of sea anemone along coastal areas in Europe and the Mediterranean. Members of this species vary in reproductive modes and presumably in genetic diversity among sites. Here we

  14. *Maractis rimicarivora*, a new genus and species of sea anemone (Cnidaria: Anthozoa: Actiniaria: Actinostolidae) from an Atlantic hydrothermal vent

    E-print Network

    Fautin, Daphne G.; Barber, Brian R.

    1999-01-01

    *Maractis rimicarivora* is a new genus and new species of medium-sized sea anemone (Actiniaria) from the TAG (Trans-Atlantic Geotraverse) hydrothermal vent fields (26°08.3'N, 44°49.6'W; 3650 m). The genus, which belongs to family Actinostolidae...

  15. Stylobates birtlesi sp. n., a new species of carcinoecium-forming sea anemone (Cnidaria, Actiniaria, Actiniidae) from eastern Australia

    PubMed Central

    Crowther, Andrea L.; Fautin, Daphne G.; Wallace, Carden C.

    2011-01-01

    Abstract We describe a new species of carcinoecium-forming sea anemone, Stylobates birtlesi sp. n., from sites 590–964 m deep in the Coral Sea, off the coast of Queensland, Australia. An anemone of this genus settles on a gastropod shell inhabited by a hermit crab, then covers and extends the shell to produce a chitinous structure termed a carcinoecium. Stylobates birtlesi sp. n. is symbiotic with the hermit crab Sympagurus trispinosus (Balss, 1911). The nature of marginal sphincter muscle and nematocyst size and distribution distinguish Stylobates birtlesi sp. n. from other species in the genus. The four known species of Stylobates are allopatric, each inhabiting a separate ocean basin of the Indo-West Pacific. We also extend the known range of Stylobates loisetteae in the Indian Ocean off the coast of Western Australia. PMID:21594082

  16. Stylobates birtlesi sp. n., a new species of carcinoecium-forming sea anemone (Cnidaria, Actiniaria, Actiniidae) from eastern Australia.

    PubMed

    Crowther, Andrea L; Fautin, Daphne G; Wallace, Carden C

    2011-01-01

    We describe a new species of carcinoecium-forming sea anemone, Stylobates birtlesisp. n., from sites 590-964 m deep in the Coral Sea, off the coast of Queensland, Australia. An anemone of this genus settles on a gastropod shell inhabited by a hermit crab, then covers and extends the shell to produce a chitinous structure termed a carcinoecium. Stylobates birtlesisp. n. is symbiotic with the hermit crab Sympagurus trispinosus (Balss, 1911). The nature of marginal sphincter muscle and nematocyst size and distribution distinguish Stylobates birtlesi sp. n. from other species in the genus. The four known species of Stylobates are allopatric, each inhabiting a separate ocean basin of the Indo-West Pacific. We also extend the known range of Stylobates loisetteae in the Indian Ocean off the coast of Western Australia. PMID:21594082

  17. Mitochondrial DNA of the sea anemone, Metridium senile (Cnidaria): Prokaryote-like genes for tRNA f-Met and small-subunit ribosomal RNA, and standard genetic code specificities for AGR and ATA codons

    Microsoft Academic Search

    Geneviève A. Pont-Kingdon; C. Timothy Beagley; Ronald Okimoto; David R. Wolstenholme

    1994-01-01

    The nucleotide sequence of a segment of the mitochondrial DNA (mtDNA) molecule of the sea anemone Metridium senile (phylum Cnidaria, class Anthozoa, order Actiniaria) has been determined, within which have been identified the genes for respiratory chain NADH dehydrogenase subunit 2 (ND2), the small-subunit rRNA (s-rRNA), cytochrome c oxidase subunit II(COII), ND4, ND6, cytochrome b (Cyt b), tRNAf-Met, and the

  18. A new species of the sea anemone *Megalactis* (Cnidaria: Anthozoa: Actiniaria: Actinodendridae) from Taiwan and designation of a neotype for the type species of the genus

    E-print Network

    Ardelean, Adorian; Fautin, Daphne G.

    2004-12-20

    *Megalactis comatus*, new species, from Taiwan is the third species in this genus of sea anemones with highly branched tentacles. The others are *M. hemprichii* Ehrenberg, 1834, from the Red Sea, and *M. griffithsi* ...

  19. Dynamic tuning of hair bundle mechanoreceptors in a sea anemone during predation

    Microsoft Academic Search

    Glen M. Watson; Patricia Mire

    2004-01-01

    The sea anemone Haliplanella luciae (Cnidaria, Anthozoa) detects chemical and mechanical stimuli from prey. Hair bundle mechanoreceptors on the tentacles participate in regulating discharge of microbasic \\u0009p-mastigophore nematocysts. Properly stimulated hair bundles sensitize the anemone to discharge nematocysts into objects that contact the tentacles. The hair bundle mechanoreceptors are composed of stereocilia derived from a multicellular complex. This complex consists

  20. Sea anemone exposed at low tide

    NSDL National Science Digital Library

    Katie Hale (California State University, Fullerton; Student, Biological Sciences)

    2007-01-05

    Sea anemones are sensitive to drying out. To avoid drying out during low tide and periods of intense sunlight, the anemones roll up to keep their tentacles moist. The outer body of the anemone is thick and tolerant of heat.

  1. A new genus and species of isanthid sea anemone (Cnidaria: Anthozoa: Actiniaria) from Chilean Patagonia, Anthoparactis fossii n. gen. et sp

    NASA Astrophysics Data System (ADS)

    Häussermann, Verena; Rodríguez, Estefanía

    2014-09-01

    We describe a new genus and species of sea anemone from Chilean Patagonia. Anthoparactis fossii n. gen. et sp. adds another acontiate genus and species to the family Isanthidae Carlgren, 1938. Anthoparactis n. gen. differs from the other isanthid genera in having the same number of mesenteries distally and proximally, acontia with basitrichs only, and a column with verrucae distally. Anthoparactis fossii n. sp. differs from the most similar species, Isoparactis fionae Lauretta et al., 2013, in the number of cycles of mesenteries and tentacles, structures of the column, colour pattern of the oral disc, cnidae, and geographical distribution. Isanthidae now includes seven genera and 11 species.

  2. Symbiont expulsion from the anemone Anthopleura elegantissima (Brandt) (Cnidaria; Anthozoa)

    Microsoft Academic Search

    L. R. McCloskey; Timothy G. Cove; E. Alan Verde

    1996-01-01

    Expulsion, mitotic index (MI), and density of two species of symbiotic algae (zooxanthellae and zoochlorellae) in the sea anemone Anthopleura elegantissima (Brandt) were examined under three irradiance conditions. Expulsion of algae, regardless of species, increased directly with irradiance, while algal density remained independent of irradiance. The MI of algae in hospite was not significantly correlated with irradiance, although the MI

  3. NAD(P)H-dependent epoxidation of aldrin in vitro by sea anemone microsomes

    Microsoft Academic Search

    L. M. Heffernan; H. F. Morris; G. W. Winston

    2000-01-01

    Previous studies from our laboratory indicated the presence of a functional P450-dependent mixed-function oxidase system (MFO) in the sea anemone (Phylum: Cnidaria). Further catalytic studies have demonstrated that sea anemone microsomes can metabolize aldrin to dieldrin through an epoxidation reaction in the presence of NAD(P)H. Based upon Nickel 63 ECD gas chromatography, dieldrin was the only metabolite detected. Further, the

  4. Field Guide to Anemone Fishes and their Host Sea Anemones

    NSDL National Science Digital Library

    Allen, Gerald R.

    Dr. Daphne G. Fautin of California Academy of Sciences and University of Kansas and Dr. Gerald R. Allen of Western Australian Museum wrote this fascinating field guide to anemone fishes and their sea anemone hosts. The five main chapters of this book cover classification and identification of sea anemones and anemone fishes in addition to their biologies, life histories, and the ecological interactions between them. Species-specific information includes common and scientific name, original description and color features/size, similar species, host species, and distribution. From students to clown fish enthusiasts to research scientists, offers a wealth of practical and intriguing information in this online book.

  5. Dynamic tuning of hair bundle mechanoreceptors in a sea anemone during predation

    Microsoft Academic Search

    Glen M. Watson; Patricia Mire

    The sea anemone Haliplanella luciae (Cnidaria, Anthozoa) detects chemical and mechanical stimuli from prey. Hair bundle mechanoreceptors on the tentacles participate\\u000a in regulating discharge of microbasic p-mastigophore nematocysts. Properly stimulated hair bundles sensitize the anemone to\\u000a discharge nematocysts into objects that contact the tentacles. The hair bundle mechanoreceptors are composed of stereocilia\\u000a derived from a multicellular complex. This complex consists

  6. Abyssal sea anemones (Cnidaria: Actiniaria) of the northeast Pacific symbiotic with molluscs: *Anthosactis nomados*, a new species, and *Monactis vestita* (Gravier, 1918)

    E-print Network

    White, Tracy R.; Wakefield Pagels, April K.; Fautin, Daphne G.

    1999-12-01

    We describe *Anthosactis nomados*, new species, which belongs to family Actinostolidae, and redescribe *Monactis vestita* (Gravier, 1918), a species belonging to family Hormathiidae. Anemones of both species live attached ...

  7. (photo courtesy of T. Kato) CHARACTERISTICS OF CNIDARIA

    E-print Network

    Fautin, Daphne

    Cnidaria (photo courtesy of T. Kato) CHARACTERISTICS OF CNIDARIA 1) Cnidae 2) Radial or biradial (biradial in polyps such as sea anemones and corals), single body #12;Section 12 CNIDARIA opening, and body. Nematocysts are a diagnostic featureof Cnidaria: if they are absent, the animal is not a cnidarian. However

  8. The ancestral role of COE genes may have been in chemoreception: evidence from the development of the sea anemone, Nematostella vectensis (Phylum Cnidaria; Class Anthozoa).

    PubMed

    Pang, Kevin; Matus, David Q; Martindale, Mark Q

    2004-03-01

    An orthologue of the COE family of helix-loop-helix transcription factors was recovered from the anthozoan Nematostella vectensis (Cnidaria). NvCOE has high sequence similarity to vertebrate and invertebrate orthologues in all three major functional domains of the protein. In situ hybridization studies show early expression through the cleavage period but transcripts are down regulated at gastrulation while remaining expressed at high levels only in the apical tuft of cilia at the aboral end of the planula larva. It is likely that one of the ancestral roles of the COE family of genes may have been in the development of chemosensory neurons. PMID:14752662

  9. Fission in sea anemones: integrative studies of life cycle evolution.

    PubMed

    Geller, Jonathan B; Fitzgerald, Laurie J; King, Chad E

    2005-08-01

    Sea anemones (Phylum Cnidaria; Class Anthozoa, Order Actiniaria) exhibit a diversity of developmental patterns that include cloning by fission. Because natural histories of clonal and aclonal sea anemones are quite different, the gain and loss of fission is an important feature of actiniarian lineages. We have used mitochondrial DNA and nuclear intron DNA phylogenies to investigate the evolution of longitudinal fission in sixteen species in the genus Anthopleura, and reconstructed an aclonal ancestor that has given rise at least four times to clonal descendents. For A. elegantissima from the northeastern Pacific Ocean, a transition to clonality by fission was associated with an up-shore habitat shift, supporting prior hypotheses that clonal growth is an adaptation to the upper shore. Fission in Actiniaria likely precedes its advent in Anthopleura, and its repeated loss and gain is perplexing. Field studies of the acontiate sea anemone Aiptasia californica provided insight to the mechanisms that regulate fission: subtidal Aiptasia responded to experimentally destabilized substrata by increasing rates of pedal laceration. We put forth a general hypothesis for actiniarian fission in which sustained tissue stretch (a consequence of substratum instability or intrinsic behavior) induces tissue degradation, which in turn induces regeneration. The gain and loss of fission in Anthopleura lineages may only require the gain and loss of some form of stretching behavior. In this view, tissue stretch initiates a cascade of developmental events without requiring complex gene regulatory linkages. PMID:21676808

  10. Neurotoxin localization to ectodermal gland cells uncovers an alternative mechanism of venom delivery in sea anemones

    PubMed Central

    Moran, Yehu; Genikhovich, Grigory; Gordon, Dalia; Wienkoop, Stefanie; Zenkert, Claudia; Özbek, Suat; Technau, Ulrich; Gurevitz, Michael

    2012-01-01

    Jellyfish, hydras, corals and sea anemones (phylum Cnidaria) are known for their venomous stinging cells, nematocytes, used for prey and defence. Here we show, however, that the potent Type I neurotoxin of the sea anemone Nematostella vectensis, Nv1, is confined to ectodermal gland cells rather than nematocytes. We demonstrate massive Nv1 secretion upon encounter with a crustacean prey. Concomitant discharge of nematocysts probably pierces the prey, expediting toxin penetration. Toxin efficiency in sea water is further demonstrated by the rapid paralysis of fish or crustacean larvae upon application of recombinant Nv1 into their medium. Analysis of other anemone species reveals that in Anthopleura elegantissima, Type I neurotoxins also appear in gland cells, whereas in the common species Anemonia viridis, Type I toxins are localized to both nematocytes and ectodermal gland cells. The nematocyte-based and gland cell-based envenomation mechanisms may reflect substantial differences in the ecology and feeding habits of sea anemone species. Overall, the immunolocalization of neurotoxins to gland cells changes the common view in the literature that sea anemone neurotoxins are produced and delivered only by stinging nematocytes, and raises the possibility that this toxin-secretion mechanism is an ancestral evolutionary state of the venom delivery machinery in sea anemones. PMID:22048953

  11. The Assimilation and Distribution of Dissolved Organic Matter By Planulae of Sea Anemones

    Microsoft Academic Search

    Slott Amy

    2007-01-01

    The free-living developmental stage of sea anemones (phylum Cnidaria) is the planula larva. In general the feeding biology of planulae is poorly known and there is only one report of the ability of planulae to assimilate dissolved organic materials (DaM, specifically amino acids) from seawater (Ben-David-Zaslow and Benayahu, 2000). We examined the ability of planula l arvae to assimilate dissolved

  12. Sea anemones possess dynamic mitogenome structures.

    PubMed

    Emblem, Åse; Okkenhaug, Siri; Weiss, Emily S; Denver, Dee R; Karlsen, Bård Ove; Moum, Truls; Johansen, Steinar D

    2014-06-01

    A notable feature of hexacoral mitogenomes is the presence of complex self-catalytic group I introns. We investigated mitogenome structural variations and evolutionary mechanisms in actiniarian sea anemones based on the complete mitogenome sequence of the cold-water sea anemone species Urticina eques, Bolocera tuediae, Hormathia digitata and Metridium senile, and two isolates of the sub-tropical Aiptasia pulchella. Whole genome sequencing at 50 times coverage of B. tuediae and H. digitata indicated low mtDNA copy number of per haploid nuclear genome and presence of rare haplotypes. A group I intron inserted in ND5 was found to host essential mitochondrial protein genes in all species, and an additional truncated copy of ND5 in B. tuediae. A second group I intron (inserted in COI) that contained a homing endonuclease gene (HEG) was present in all mtDNA examined. Different variants of HEGs were observed, and included expressed elements fused in-frame with upstream exons and free-standing HEGs embedded within the intron. A notable hallmark of HEGs was a high extent of overlap with ribozyme structural elements; the U. eques HEG overlapped with the entire intron. We reconstructed the evolutionary history of the COI intron from insertion at unoccupied cognate sites, through HEG degradation, to intron loss. We also identified a novel insertion element in U. eques that contained two expressed protein-coding genes. An evolutionary analysis of the sea anemone mtDNA genes revealed higher substitution rates in the HEG and the insertion sequence as compared to the other loci, indicating relaxed selective pressures in these elements. We conclude that sea anemone mitogenomes are surprisingly dynamic in structure despite the economical organization and low sequence mutation rate. PMID:24613805

  13. Sea Anemone Toxins Affecting Potassium Channels

    NASA Astrophysics Data System (ADS)

    Diochot, Sylvie; Lazdunski, Michel

    The great diversity of K+ channels and their wide distribution in many tissues are associated with important functions in cardiac and neuronal excitability that are now better understood thanks to the discovery of animal toxins. During the past few decades, sea anemones have provided a variety of toxins acting on voltage-sensitive sodium and, more recently, potassium channels. Currently there are three major structural groups of sea anemone K+ channel (SAK) toxins that have been characterized. Radioligand binding and electrophysiological experiments revealed that each group contains peptides displaying selective activities for different subfamilies of K+ channels. Short (35-37 amino acids) peptides in the group I display pore blocking effects on Kv1 channels. Molecular interactions of SAK-I toxins, important for activity and binding on Kv1 channels, implicate a spot of three conserved amino acid residues (Ser, Lys, Tyr) surrounded by other less conserved residues. Long (58-59 amino acids) SAK-II peptides display both enzymatic and K+ channel inhibitory activities. Medium size (42-43 amino acid) SAK-III peptides are gating modifiers which interact either with cardiac HERG or Kv3 channels by altering their voltage-dependent properties. SAK-III toxins bind to the S3C region in the outer vestibule of Kv channels. Sea anemones have proven to be a rich source of pharmacological tools, and some of the SAK toxins are now useful drugs for the diagnosis and treatment of autoimmune diseases.

  14. RESEARCH ARTICLE Open Access Mutualism with sea anemones triggered the

    E-print Network

    Zimmermann, Niklaus E.

    RESEARCH ARTICLE Open Access Mutualism with sea anemones triggered the adaptive radiation to access resources untapped by competitors, but evidence shows that the effect of mutualism on species mutualism with sea anemones allowed the clownfishes to radiate adaptively across the Indian and western

  15. NF-?B is required for cnidocyte development in the sea anemone Nematostella vectensis.

    PubMed

    Wolenski, Francis S; Bradham, Cynthia A; Finnerty, John R; Gilmore, Thomas D

    2013-01-01

    The sea anemone Nematostella vectensis (Nv) is a leading model organism for the phylum Cnidaria, which includes anemones, corals, jellyfishes and hydras. A defining trait across this phylum is the cnidocyte, an ectodermal cell type with a variety of functions including defense, prey capture and environmental sensing. Herein, we show that the Nv-NF-?B transcription factor and its inhibitor Nv-I?B are expressed in a subset of cnidocytes in the body column of juvenile and adult anemones. The size and distribution of the Nv-NF-?B-positive cnidocytes suggest that they are in a subtype known as basitrichous haplonema cnidocytes. Nv-NF-?B is primarily cytoplasmic in cnidocytes in juvenile and adult animals, but is nuclear when first detected in the 30-h post-fertilization embryo. Morpholino-mediated knockdown of Nv-NF-?B expression results in greatly reduced cnidocyte formation in the 5 day-old animal. Taken together, these results indicate that NF-?B plays a key role in the development of the phylum-specific cnidocyte cell type in Nematostella, likely by nuclear Nv-NF-?B-dependent activation of genes required for cnidocyte development. PMID:23063796

  16. Mechanosensitivity in the model sea anemone Nematostella vectensis

    Microsoft Academic Search

    Glen M. Watson; Patricia Mire; Katherine M. Kinler

    2009-01-01

    Tentacles of the sea anemone, Nematostella vectensis, are covered with hair bundles. Hair bundles were deflected by water jets to test whether they are mechanoreceptors. Electrophysiological\\u000a recordings confirm that deflections of hair bundles induce transients in membrane current. In a different species of anemone,\\u000a hair bundle mechanoreceptors are known to change shape and responsiveness according to the activity of chemoreceptors

  17. Biochemical and electrophysiological characterization of two sea anemone type 1 potassium toxins from a geographically distant population of Bunodosoma caissarum.

    PubMed

    Orts, Diego J B; Peigneur, Steve; Madio, Bruno; Cassoli, Juliana S; Montandon, Gabriela G; Pimenta, Adriano M C; Bicudo, José E P W; Freitas, José C; Zaharenko, André J; Tytgat, Jan

    2013-03-01

    Sea anemone (Cnidaria, Anthozoa) venom is an important source of bioactive compounds used as tools to study the pharmacology and structure-function of voltage-gated K+ channels (KV). These neurotoxins can be divided into four different types, according to their structure and mode of action. In this work, for the first time, two toxins were purified from the venom of Bunodosoma caissarum population from Saint Peter and Saint Paul Archipelago, Brazil. Sequence alignment and phylogenetic analysis reveals that BcsTx1 and BcsTx2 are the newest members of the sea anemone type 1 potassium channel toxins. Their functional characterization was performed by means of a wide electrophysiological screening on 12 different subtypes of KV channels (KV1.1-KV1.6; KV2.1; KV3.1; KV4.2; KV4.3; hERG and Shaker IR). BcsTx1 shows a high affinity for rKv1.2 over rKv1.6, hKv1.3, Shaker IR and rKv1.1, while Bcstx2 potently blocked rKv1.6 over hKv1.3, rKv1.1, Shaker IR and rKv1.2. Furthermore, we also report for the first time a venom composition and biological activity comparison between two geographically distant populations of sea anemones. PMID:23466933

  18. Biochemical and Electrophysiological Characterization of Two Sea Anemone Type 1 Potassium Toxins from a Geographically Distant Population of Bunodosoma caissarum

    PubMed Central

    Orts, Diego J. B.; Peigneur, Steve; Madio, Bruno; Cassoli, Juliana S.; Montandon, Gabriela G.; Pimenta, Adriano M. C.; Bicudo, José E. P. W.; Freitas, José C.; Zaharenko, André J.; Tytgat, Jan

    2013-01-01

    Sea anemone (Cnidaria, Anthozoa) venom is an important source of bioactive compounds used as tools to study the pharmacology and structure-function of voltage-gated K+ channels (KV). These neurotoxins can be divided into four different types, according to their structure and mode of action. In this work, for the first time, two toxins were purified from the venom of Bunodosoma caissarum population from Saint Peter and Saint Paul Archipelago, Brazil. Sequence alignment and phylogenetic analysis reveals that BcsTx1 and BcsTx2 are the newest members of the sea anemone type 1 potassium channel toxins. Their functional characterization was performed by means of a wide electrophysiological screening on 12 different subtypes of KV channels (KV1.1–KV1.6; KV2.1; KV3.1; KV4.2; KV4.3; hERG and Shaker IR). BcsTx1 shows a high affinity for rKv1.2 over rKv1.6, hKv1.3, Shaker IR and rKv1.1, while Bcstx2 potently blocked rKv1.6 over hKv1.3, rKv1.1, Shaker IR and rKv1.2. Furthermore, we also report for the first time a venom composition and biological activity comparison between two geographically distant populations of sea anemones. PMID:23466933

  19. Trench warfare on the shore: interclonalaggression in sea anemones

    E-print Network

    Bermingham, Eldredge

    Trench warfare on the shore: interclonalaggression in sea anemones mpirical research in behavioral the possibility ofretreat,the losermay die. Trench warfare is a sociallyorganized behavior,and the biology the no-man'sland between the trenches of opposing forces in World War 1. Like the Western Front

  20. Mating systems in the sea anemone genus Epiactis

    Microsoft Academic Search

    S. Edmands

    1995-01-01

    Four morphologically similar species in the sea anemone genus Epiactis exhibit overlapping distributions on the Pacific coast of North America; E. prolifera, E. lisbethae, E. ritteri and E. fernaldi. All brood their offspring up to the juvenile stage, but each has a different combination of internal versus external brooding and hermaphroditism versus gonochory (separate sexes). Specimens were collected from sites

  1. Symbiosis of sea anemones and hermit crabs: different resource utilization patterns in the Aegean Sea

    NASA Astrophysics Data System (ADS)

    Vafeiadou, Anna-Maria; Antoniadou, Chryssanthi; Chintiroglou, Chariton

    2012-09-01

    The small-scale distribution and resource utilization patterns of hermit crabs living in symbiosis with sea anemones were investigated in the Aegean Sea. Four hermit crab species, occupying shells of nine gastropod species, were found in symbiosis with the sea anemone Calliactis parasitica. Shell resource utilization patterns varied among hermit crabs, with Dardanus species utilizing a wide variety of shells. The size structure of hermit crab populations also affected shell resource utilization, with small-sized individuals inhabiting a larger variety of shells. Sea anemone utilization patterns varied both among hermit crab species and among residence shells, with larger crabs and shells hosting an increased abundance and biomass of C. parasitica. The examined biometric relationships suggested that small-sized crabs carry, proportionally to their weight, heavier shells and increased anemone biomass than larger ones. Exceptions to the above patterns are related either to local resource availability or to other environmental factors.

  2. Nematocysts of sea anemones (Actiniaria, Ceriantharia and Corallimorpharia: Cnidaria): nomenclature

    Microsoft Academic Search

    K. W. England; E. A. Robson

    1991-01-01

    A brief historical review of nematocyst terminology is given and three nomenclatural problems are discussed. It is proposed to combine the terms initiated by Weill (1934) with those of Schmidt (1969). A new mesobasic grade, intermediate between microbasic and macrobasic is proposed for amastigophores and p-mastigophores possessing a short Faltstück. A more liberal interpretation of Weill's (1934) terminology for nematocysts

  3. Nutrient Enrichment Coupled with Sedimentation Favors Sea Anemones over Corals.

    PubMed

    Liu, Pi-Jen; Hsin, Min-Chieh; Huang, Yen-Hsun; Fan, Tung-Yung; Meng, Pei-Jie; Lu, Chung-Cheng; Lin, Hsing-Juh

    2015-01-01

    Fine sediments, which account for the majority of total fluvial sediment flux, have been suggested to degrade coral reefs on a global scale. Furthermore, sediment impacts can be exacerbated by extreme rainfall events associated with global climate change and anthropogenic nutrient enrichment. We report the findings from a series of mesocosm experiments exploring the effects of short-term sedimentation and nutrient enrichment on the interactions between the hard coral Acropora muricata, the sea anemone Mesactinia ganesis, and the green macroalga Codium edule. Mesocosms were manipulated to simulate either unimpacted reefs or reefs exposed to elevated levels of fine sediments for 10 or 14 days to simulate the effects of heavy rainfall. The first and second experiments were aimed to examine the effects of inorganic and organic sediments, respectively. The third experiment was designed to examine the interactive effects of nutrient enrichment and elevated sediment loads. Neither inorganic nor organic sediment loadings significantly affected the physiological performance of the coral, but, importantly, did reduce its ability to compete with other organisms. Photosynthetic efficiencies of both the green macroalga and the sea anemone increased in response to both sediment loadings when they were simultaneously exposed to nutrient enrichment. While organic sediment loading increased the nitrogen content of the green macroalga in the first experiment, inorganic sediment loading increased its phosphorus content in the second experiment. The coral mortality due to sea anemones attack was significantly greater upon exposure to enriched levels of organic sediments and nutrients. Our findings suggest that the combined effects of short-term sedimentation and nutrient enrichment could cause replacement of corals by sea anemones on certain coral reefs. PMID:25897844

  4. Mutualism with sea anemones triggered the adaptive radiation of clownfishes

    PubMed Central

    2012-01-01

    Background Adaptive radiation is the process by which a single ancestral species diversifies into many descendants adapted to exploit a wide range of habitats. The appearance of ecological opportunities, or the colonisation or adaptation to novel ecological resources, has been documented to promote adaptive radiation in many classic examples. Mutualistic interactions allow species to access resources untapped by competitors, but evidence shows that the effect of mutualism on species diversification can greatly vary among mutualistic systems. Here, we test whether the development of obligate mutualism with sea anemones allowed the clownfishes to radiate adaptively across the Indian and western Pacific oceans reef habitats. Results We show that clownfishes morphological characters are linked with ecological niches associated with the sea anemones. This pattern is consistent with the ecological speciation hypothesis. Furthermore, the clownfishes show an increase in the rate of species diversification as well as rate of morphological evolution compared to their closest relatives without anemone mutualistic associations. Conclusions The effect of mutualism on species diversification has only been studied in a limited number of groups. We present a case of adaptive radiation where mutualistic interaction is the likely key innovation, providing new insights into the mechanisms involved in the buildup of biodiversity. Due to a lack of barriers to dispersal, ecological speciation is rare in marine environments. Particular life-history characteristics of clownfishes likely reinforced reproductive isolation between populations, allowing rapid species diversification. PMID:23122007

  5. Nanotoxicology using the sea anemone Nematostella vectensis: from developmental toxicity to genotoxicology.

    PubMed

    Ambrosone, Alfredo; Marchesano, Valentina; Mazzarella, Veronica; Tortiglione, Claudia

    2014-08-01

    Concomitant with the fast-growing advances in the synthesis and engineering of colloidal nanocrystals, an urgent evaluation of their toxicity on human beings and environment is strongly encouraged by public health organisations. Despite the in vitro approaches employed for toxicological screening of hazardous compounds, the use of simple and cost-effective living organisms may enormously contribute to solve unanswered questions related to embryotoxic and teratogenic effects of nanomaterials. Here, the sea anemone Nematostella vectensis (Cnidaria, Anthozoa) is presented as a novel model organism to profile bio/non-bio interactions and to show a comprehensive toxicological analysis performed on embryos, larvae and adults treated with fluorescent cadmium-based nanocrystals. Spanning from in vivo biodistribution to molecular investigations, different behaviours and effects depending on the composition and surface coatings are showed. Rod-shaped cadmium selenide/cadmium sulfide (CdSe/CdS) nanocrystals resulted in excellent imaging probes to track N. vectensis development with negligible adverse effects, while spherical CdTe nanocrystals severely impaired embryogenesis, resulting in aberrant phenotypes and deregulation of developmental genes, which raise severe worries for a safe use of this type of nanoparticles for human purposes and environmental contamination. PMID:23641943

  6. Structural characterization of a blue chromoprotein and its yellow mutant from the sea anemone Cnidopus japonicus.

    PubMed

    Chan, Mitchell C Y; Karasawa, Satoshi; Mizuno, Hideaki; Bosanac, Ivan; Ho, Dona; Privé, Gilbert G; Miyawaki, Atsushi; Ikura, Mitsuhiko

    2006-12-01

    Green fluorescent protein (GFP) and its relatives (GFP protein family) have been isolated from marine organisms such as jellyfish and corals that belong to the phylum Cnidaria (stinging aquatic invertebrates). They are intrinsically fluorescent proteins. In search of new members of the family of green fluorescent protein family, we identified a non-fluorescent chromoprotein from the Cnidopus japonicus species of sea anemone that possesses 45% sequence identity to dsRed (a red fluorescent protein). This newly identified blue color protein has an absorbance maximum of 610 nm and is hereafter referred to as cjBlue. Determination of the cjBlue 1.8 A crystal structure revealed a chromophore comprised of Gln(63)-Tyr(64)-Gly(65). The ring stacking between Tyr(64) and His(197) stabilized the cjBlue trans chromophore conformation along the Calpha2-Cbeta2 bond of 5-[(4-hydroxyphenyl)methylene]-imidazolinone, which closely resembled that of the "Kindling Fluorescent Protein" and Rtms5. Replacement of Tyr(64) with Leu in wild-type cjBlue produced a visible color change from blue to yellow with a new absorbance maximum of 417 nm. Interestingly, the crystal structure of the yellow mutant Y64L revealed two His(197) imidazole ring orientations, suggesting a flip-flop interconversion between the two conformations in solution. We conclude that the dynamics and structure of the chromophore are both essential for the optical appearance of these color proteins. PMID:17028187

  7. Shallow-Water Sea Anemones (Cnidaria: Anthozoa: Actiniaria) and Tube Anemones (Cnidaria: Anthozoa: Ceriantharia) of the Galápagos Islands

    E-print Network

    Fautin, Daphne G.; Hickman, Cleveland P. Jr.; Daly, Marymegan; Molodtsova, Tina

    2007-10-01

    Basitrichs (B) (11.2) 13.7–17.5 #4; 1.7–2.9 26 3/3 Basitrichs (C) 20.4–35.2 (36.3) #4; 2.2–5.5 17 2/3 Microbasic p-mastigophores (D) (20.1) 22.6–28.8 (32.3) #4; 4.1–5.7 21 2/3 Column Basitrichs (B) (14.1) 15.1–20.6 (22.1) #4; 1.8–3.1 (3.8) 29 2/2 Basitrichs...

  8. Respiratory response of the sea anemone Bunodosoma cavernata (Bosc) to changes in temperature and salinity

    E-print Network

    Retzer, Kent Arnold

    1985-01-01

    RESPIRATORY RESPONSE OF THE SEA ANEMONE BUNODOSOMA CAVERNATA (BOSE) TO CHANGES IN TEMPERATURE AND SALINITY A Thesis by KENT ARNOLD RETZER Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE May 19BS Major Subject: Biology RESPIRATORY RESPONSE OF THE SEA ANEMONE BUNODOSOMA CAVERNATA (6OSC) TO CHANGES IN TEMPERATURE AND SALINITY A Thesi s by KENT ARNOLD RETZER g7 Elenor R. Cox (Chairman of Committee...

  9. Continuous drug release by sea anemone Nematostella vectensis stinging microcapsules.

    PubMed

    Tal, Yossi; Ayalon, Ari; Sharaev, Agnesa; Kazir, Zoya; Brekhman, Vera; Lotan, Tamar

    2014-02-01

    Transdermal delivery is an attractive option for drug delivery. Nevertheless, the skin is a tough barrier and only a limited number of drugs can be delivered through it. The most difficult to deliver are hydrophilic drugs. The stinging mechanism of the cnidarians is a sophisticated injection system consisting of microcapsular nematocysts, which utilize built-in high osmotic pressures to inject a submicron tubule that penetrates and delivers their contents to the prey. Here we show, for the first time, that the nematocysts of the starlet sea anemone Nematostella vectensis can be isolated and incorporated into a topical formulation for continuous drug delivery. We demonstrate quantitative delivery of nicotinamide and lidocaine hydrochloride as a function of microcapsular dose or drug exposure. We also show how the released submicron tubules can be exploited as a skin penetration enhancer prior to and independently of drug application. The microcapsules are non-irritant and may offer an attractive alternative for hydrophilic transdermal drug delivery. PMID:24473172

  10. Continuous Drug Release by Sea Anemone Nematostella vectensis Stinging Microcapsules

    PubMed Central

    Tal, Yossi; Ayalon, Ari; Sharaev, Agnesa; Kazir, Zoya; Brekhman, Vera; Lotan, Tamar

    2014-01-01

    Transdermal delivery is an attractive option for drug delivery. Nevertheless, the skin is a tough barrier and only a limited number of drugs can be delivered through it. The most difficult to deliver are hydrophilic drugs. The stinging mechanism of the cnidarians is a sophisticated injection system consisting of microcapsular nematocysts, which utilize built-in high osmotic pressures to inject a submicron tubule that penetrates and delivers their contents to the prey. Here we show, for the first time, that the nematocysts of the starlet sea anemone Nematostella vectensis can be isolated and incorporated into a topical formulation for continuous drug delivery. We demonstrate quantitative delivery of nicotinamide and lidocaine hydrochloride as a function of microcapsular dose or drug exposure. We also show how the released submicron tubules can be exploited as a skin penetration enhancer prior to and independently of drug application. The microcapsules are non-irritant and may offer an attractive alternative for hydrophilic transdermal drug delivery. PMID:24473172

  11. Photosynthesis and respiration of two species of algal symbionts in the anemone Anthopleura elegantissima (Brandt) (Cnidaria; Anthozoa)

    Microsoft Academic Search

    E. Alan Verde; L. R. McCloskey

    1996-01-01

    In parts of its range, the anemone Anthopleura elegantissima (Brandt) is populated by two different symbiotic algae: zoochlorellae and zooxanthellae. Anemones with exclusively one or the other symbiont were compared under identical conditions. A zooxanthella was about twice the volume and carbon content of a zoochlorella, and contained more chlorophyll. Zooxanthellae population density was 24% less than zoochlorellae, consequently zooxanthellae

  12. Development of a rational nomenclature for naming peptide and protein toxins from sea anemones.

    PubMed

    Oliveira, Joacir Stolarz; Fuentes-Silva, Deyanira; King, Glenn F

    2012-09-15

    Sea anemone toxins are predominantly peptide and proteins that act mainly on sodium and potassium channels, as well as in a variety of target cells causing lysis. Over recent years, the number of sea anemone peptide toxins as well as cytolytic pore-forming proteins and phospholipase A(2) sequences submitted to databases has been rapidly increasing due to the developments in DNA sequencing technology and proteomic approaches. However, the lack of a systematic nomenclature has resulted in multiple names being assigned to the same toxins, toxins from unrelated species being designated by the same name, and ambiguous name designations. Therefore, in this work we propose a systematic nomenclature in which we adopted specific criteria, based on order of discovery and phylogenetic analysis, in order to avoid redundant sea anemone toxin names. Implementation of the nomenclature proposed here not only allowed us to rename the already published 191 anemone toxins without ambiguities, but it can be used to unambiguously name newly discovered toxins whether or not they are related to previously published sea anemone sequences. In the new nomenclature each toxin name contains information about the toxin's biological activity, origin and relationship to known isoforms. Ongoing increases in the speed of DNA sequencing will raise significantly the number of sea anemone toxin sequences in the literature. This will represent a constant challenge in their clear identification and logical classification, which could be solved using the proposed nomenclature. PMID:22683676

  13. The Culture Sexual and Asexual Reproduction and Growth of the Sea Anemone Nematostella vectensis

    Microsoft Academic Search

    Cadet Hand; Kevin R. Uhlinger

    Abstract. Nematostella vectensis, a widely distributed, burrowing sea anemone, was raised through successive sexual generations at room,temperature,in non-circulating seawater. It has separate sexes and,also reproduces,asex- ually by transverse fission. Cultures of animals,were,fed Artemia,sp. nauplii every second,day. Every eight days the culture water was changed, and the anemones were fed pieces,of Mytilus spp. tissue. This led to,regular spawning,by both sexes at

  14. Light Entrained Rhythmic Gene Expression in the Sea Anemone Nematostella vectensis: The Evolution of the Animal Circadian Clock

    PubMed Central

    Reitzel, Adam M.; Behrendt, Lars; Tarrant, Ann M.

    2010-01-01

    Background Circadian rhythms in behavior and physiology are the observable phenotypes from cycles in expression of, interactions between, and degradation of the underlying molecular components. In bilaterian animals, the core molecular components include Timeless-Timeout, photoreceptive cryptochromes, and several members of the basic-loop-helix-Per-ARNT-Sim (bHLH-PAS) family. While many of core circadian genes are conserved throughout the Bilateria, their specific roles vary among species. Here, we identify and experimentally study the rhythmic gene expression of conserved circadian clock members in a sea anemone in order to characterize this gene network in a member of the phylum Cnidaria and to infer critical components of the clockwork used in the last common ancestor of cnidarians and bilaterians. Methodology/Principal Findings We identified homologs of circadian regulatory genes in the sea anemone Nematostella vectensis, including a gene most similar to Timeout, three cryptochromes, and several key bHLH-PAS transcription factors. We then maintained N. vectensis either in complete darkness or in a 12 hour light: 12 hour dark cycle in three different light treatments (blue only, full spectrum, blue-depleted). Gene expression varied in response to light cycle and light treatment, with a particularly strong pattern observed for NvClock. The cryptochromes more closely related to the light-sensitive clade of cryptochromes were upregulated in light treatments that included blue wavelengths. With co-immunoprecipitation, we determined that heterodimerization between CLOCK and CYCLE is conserved within N. vectensis. Additionally, we identified E-box motifs, DNA sequences recognized by the CLOCK:CYCLE heterodimer, upstream of genes showing rhythmic expression. Conclusions/Significance This study reveals conserved molecular and functional components of the circadian clock that were in place at the divergence of the Cnidaria and Bilateria, suggesting the animal circadian clockwork is more ancient than previous data suggest. Characterizing circadian regulation in a cnidarian provides insight into the early origins of animal circadian rhythms and molecular regulation of environmentally cued behaviors. PMID:20877728

  15. Masquerade, mimicry and crypsis of the polymorphic sea anemone Phyllodiscus semoni and its aggregations in South Sulawesi

    Microsoft Academic Search

    B. Hoeksema; A. L. Crowther

    2011-01-01

    Phyllodiscus semoni is a morphologically variable sea anemone species from the Indo-Pacific with morphotypes ranging from upright and branched to low-lying and rounded. The apparent camouflage strategies of this sea anemone allow it to resemble other species or objects in its environment, such as stony corals, soft corals, seaweeds, or rocky boulders covered by algae, which may help it to

  16. Structural Characterization of a Blue Chromoprotein and Its Yellow Mutant from the Sea Anemone Cnidopus Japonicus*S

    E-print Network

    Ikura, Mitsuhiko

    Structural Characterization of a Blue Chromoprotein and Its Yellow Mutant from the Sea Anemone-fluores- cent chromoprotein from the Cnidopus japonicus species of sea anemone that possesses 45% sequence-fluorescent chromoproteins (CPs) (3, 4). The GFP chromophore arises through a unique autocatalytic post- translational

  17. Integrins of the starlet sea anemone Nematostella vectensis.

    PubMed

    Gong, Qizhi; Garvey, Katrina; Qian, Chenghao; Yin, Isabel; Wong, Gary; Tucker, Richard P

    2014-12-01

    Integrins are extracellular matrix receptors composed of ? and ? subunits. Here we describe two ? subunits and four ? subunits from the starlet sea anemone Nematostella vectensis. Phylogenetic analysis suggests that the ? subunits are most closely related to RGD- and LDV-dependent ? subunits of chordates. The ? subunits cluster with the previously described ? integrins of the hard coral Acropora millepora. The expression of one of the ? subunits and three of the ? subunits was confirmed by reverse transcription PCR and in situ hybridization. The ? subunit is primarily expressed in cells near muscles, by a subset of gastrodermal cells, and in the gonad. The three ? subunits each have distinctive patterns of expression: one is concentrated in the gonad and mesenteric filament, another is found in a subset of cells in the epidermis of the oral region and in a subset of gastrodermal cells in the mesenteries, and a third is expressed widely. Changes in expression were also studied 48 h after horizontal transection by quantitative reverse transcription PCR and in situ hybridization. One of the ? subunits is expressed 8-fold higher during regeneration, and its expression is observed in cells within both the epidermis and the gastrodermis at the site of regeneration. Our observations confirm that complex patterns of integrin expression were already present in basal metazoans. The integrins expressed in the gonads may play roles in mediating sperm-egg interactions in N. vectensis, while others may play a role in regulating proliferation during regeneration. PMID:25572209

  18. Sea anemone venom as a source of insecticidal peptides acting on voltage-gated Na+ channels

    PubMed Central

    Bosmans, Frank; Tytgat, Jan

    2007-01-01

    Sea anemones produce a myriad of toxic peptides and proteins of which a large group acts on voltage-gated Na+ channels. However, in comparison to other organisms, their venoms and toxins are poorly studied. Most of the known voltage-gated Na+ channel toxins isolated from sea anemone venoms act on neurotoxin receptor site 3 and inhibit the inactivation of these channels. Furthermore, it seems that most of these toxins have a distinct preference for crustaceans. Given the close evolutionary relationship between crustaceans and insects, it is not surprising that sea anemone toxins also profoundly affect insect voltage-gated Na+ channels, which constitutes the scope of this review. For this reason, these peptides can be considered as insecticidal lead compounds in the development of insecticides. PMID:17224168

  19. Cadherin-23 may be dynamic in hair bundles of the model sea anemone Nematostella vectensis.

    PubMed

    Tang, Pei-Ciao; Watson, Glen M

    2014-01-01

    Cadherin 23 (CDH23), a component of tip links in hair cells of vertebrate animals, is essential to mechanotransduction by hair cells in the inner ear. A homolog of CDH23 occurs in hair bundles of sea anemones. Anemone hair bundles are located on the tentacles where they detect the swimming movements of nearby prey. The anemone CDH23 is predicted to be a large polypeptide featuring a short exoplasmic C-terminal domain that is unique to sea anemones. Experimentally masking this domain with antibodies or mimicking this domain with free peptide rapidly disrupts mechanotransduction and morphology of anemone hair bundles. The loss of normal morphology is accompanied, or followed by a decrease in F-actin in stereocilia of the hair bundles. These effects were observed at very low concentrations of the reagents, 0.1-10 nM, and within minutes of exposure. The results presented herein suggest that: (1) the interaction between CDH23 and molecular partners on stereocilia of hair bundles is dynamic and; (2) the interaction is crucial for normal mechanotransduction and morphology of hair bundles. PMID:24465885

  20. Cadherin-23 May Be Dynamic in Hair Bundles of the Model Sea Anemone Nematostella vectensis

    PubMed Central

    Tang, Pei-Ciao; Watson, Glen M.

    2014-01-01

    Cadherin 23 (CDH23), a component of tip links in hair cells of vertebrate animals, is essential to mechanotransduction by hair cells in the inner ear. A homolog of CDH23 occurs in hair bundles of sea anemones. Anemone hair bundles are located on the tentacles where they detect the swimming movements of nearby prey. The anemone CDH23 is predicted to be a large polypeptide featuring a short exoplasmic C-terminal domain that is unique to sea anemones. Experimentally masking this domain with antibodies or mimicking this domain with free peptide rapidly disrupts mechanotransduction and morphology of anemone hair bundles. The loss of normal morphology is accompanied, or followed by a decrease in F-actin in stereocilia of the hair bundles. These effects were observed at very low concentrations of the reagents, 0.1–10 nM, and within minutes of exposure. The results presented herein suggest that: (1) the interaction between CDH23 and molecular partners on stereocilia of hair bundles is dynamic and; (2) the interaction is crucial for normal mechanotransduction and morphology of hair bundles. PMID:24465885

  1. Effects of starvation, and light and dark on the energy metabolism of symbiotic and aposymbiotic sea anemones, Anthopleura elegantissima

    Microsoft Academic Search

    W. K. Fitt; R. L. Pardy

    1981-01-01

    Rates of oxygen and carbon-dioxide exhange were measured in symbiotic and aposymbiotic specimens of the sea anemone Anthopleura elegantissima while fed and starved under light or dark conditions. Respiratory quotients indicated that fed anemones switched from a carbohydrate to a fat catabolism when starved, with the exception that symbiotic individuals starved in the light showed a pronounced carbohydrate catabolism for

  2. Comparison of developmental trajectories in the starlet sea anemone Nematostella vectensis: embryogenesis, regeneration, and two forms of asexual fission

    Microsoft Academic Search

    Adam M. Reitzel; Patrick M. Burton; Cassandra Krone; John R. Finnertya

    2007-01-01

    The starlet sea anemone, Nematostella vectensis, is a small burrowing estuarine animal, native to the Atlantic coast of North America. In recent years, this anemone has emerged as a model system in cnidarian developmental biology. Molecular studies of em- bryology and larval development in N. vectensis have provided important insights into the evolution of key metazoan traits. However, the adult

  3. Tiny Sea Anemone from the Lower Cambrian of China

    Microsoft Academic Search

    Jian Han; Shin Kubota; Hiro-omi Uchida; George D. Stanley; Xiaoyong Yao; Degan Shu; Yong Li; Kinya Yasui

    2010-01-01

    BackgroundAbundant fossils from the Ediacaran and Cambrian showing cnidarian grade grossly suggest that cnidarian diversification occurred earlier than that of other eumetazoans. However, fossils of possible soft-bodied polyps are scanty and modern corals are dated back only to the Middle Triassic, although molecular phylogenetic results support the idea that anthozoans represent the first major branch of the Cnidaria. Because of

  4. A new Fenestrulina (Bryozoa, Cheilostomata) commensal with tube-dwelling anemones (Cnidaria, Ceriantharia) in the tropical southwestern Atlantic.

    PubMed

    Vieira, Leandro M; Stampar, Sergio N

    2014-01-01

    A new species of cheilostome bryozoan, Fenestrulina commensalis n. sp., was collected in December 2008 by scuba at 5-10 meters depth at Guaibura Beach, Guarapari, Espírito Santo state, southeastern Brazil. The specimen was found associated with tubes of the cerianthid Pachycerianthus sp., representing the first commensal association between a bryozoan and a tube-dwelling anemone. Fenestrulina commensalis n. sp. is the third species of the genus found in Brazilian waters; it is distinguished from other Atlantic species of Fenestrulina by its small angular orificial condyles, a single oral spine and basal anchoring rhizoids arising from abfrontal pore chambers. Morphological adaptations to encrust the tubes of cerianthids include anchoring rootlets and weakly contiguous zooids. These morphological features allow the colony the flexibility to grow around the tube and feed relatively undisturbed by silt and detritus, being raised well above the soft-sediment substratum in which the tube-anemone grows. PMID:24871841

  5. Potential-dependent effects of sea anemone toxins and scorpion venom on crayfish giant axon

    Microsoft Academic Search

    Akira Warashina; Shozo Fujita; Mei Satake

    1981-01-01

    Effects of two kinds of sea anemone toxin (Parasicyonis actinostoloides andAnemonia sulcata) and scorpion venom (Leiurus quinquestriatus) on crayfish giant axons were examined electrophysiologically. All toxins acted on the axon in a similar manner to prolong the falling phase of the action potential. In all cases the development of toxicity was reduced when the nerve membrane was depolarized by a

  6. Do reproductive tactics vary with habitat heterogeneity in the intertidal sea anemone Actinia tenebrosa?

    Microsoft Academic Search

    Craig D. H. Sherman; Amanda J. Peucker; David J. Ayre

    2007-01-01

    Cnidarians display a diverse range of reproductive tactics including sexual and asexual modes of reproduction. Although few studies have looked for intraspecific variation in reproductive tactics, flexible expression of such life-history traits may be favoured in species that occupy a range of habitats. We tested this in the sea anemone Actinia tenebrosa by comparing cycles of reproductive activity and the

  7. Sexual Plasticity and Self-Fertilization in the Sea Anemone Aiptasia diaphana

    Microsoft Academic Search

    Ami Schlesinger; Esti Kramarsky-Winter; Hanna Rosenfeld; Rachel Armoza-Zvoloni; Yossi Loya; Ryan L. Earley

    2010-01-01

    Traits that influence reproductive success and contribute to reproductive isolation in animal and plant populations are a central focus of evolutionary biology. In the present study we used an experimental approach to demonstrate the occurrence of environmental effects on sexual and asexual reproduction, and provide evidence for sexual plasticity and inter-clonal fertilization in laboratory-cultured lines of the sea anemone Aiptasia

  8. Genetic subdivision in the subtidal, clonal sea anemone Anthothoe albocincta

    Microsoft Academic Search

    M. Billingham; D. J. Ayre

    1996-01-01

    Anthothoe albocincta, a common subtidal anemone along south-eastern Australia, reproduces both sexually through broadcast spawning and clonally through fission. Clones may be distinguished both by their electrophoretic genotypes and the colour of their tentacles and oral discs. Local populations typically consist of many, dense clonal aggregations. However, some clones appear to have locally extensive distributions, forming a series of separate

  9. Collecting, rearing, spawning and inducing regeneration of the starlet sea anemone, Nematostella vectensis.

    PubMed

    Stefanik, Derek J; Friedman, Lauren E; Finnerty, John R

    2013-05-01

    Over the past 20 years, the starlet sea anemone, Nematostella vectensis, a small estuarine animal, has emerged as a powerful model system for field and laboratory studies of development, evolution, genomics, molecular biology and toxicology. Here we describe how to collect Nematostella, culture it through its entire sexual life cycle and induce regeneration for the production of clonal stocks. In less than 1 h at a suitable field site, a researcher on foot can collect hundreds of individual anemones. In a few months, it is possible to establish a laboratory colony that will be reliable in generating hundreds or thousands of fertilized eggs on a roughly weekly schedule. By inducing regeneration roughly every 2 weeks, in less than 6 months, one can establish a clonal stock consisting of hundreds of genetically identical anemones. These results can be achieved very inexpensively and without specialized equipment. PMID:23579780

  10. The expansion behaviour of sea anemones may be coordinated by two inhibitory neuropeptides, Antho-KAamide and Antho-RIamide.

    PubMed

    McFarlane, I D; Hudman, D; Nothacker, H P; Grimmelikhuijzen, C J

    1993-08-23

    Antho-KAamide (L-3-phenyllactyl-Phe-Lys-Ala-NH2) and Antho-RIamide (L-3-phenyllactyl-Tyr-Arg-Ile-NH2) are novel neuropeptides isolated from the sea anemone Anthopleura elegantissima. They both inhibited spontaneous contractions of isolated muscle preparations from a wide variety of anemone species (threshold around 10(-7) M). Their actions were universal in that they inhibited every muscle preparation tested, regardless of whether the muscle group was located in the ectoderm or endoderm, or was oriented in a circular or longitudinal direction. Injection of Antho-KAamide or Antho-RIamide into the coelenteron of intact sea anemones resulted in a marked expansion of the animals. Similar shape changes followed feeding or exposure to soluble food extracts. Therefore, we hypothesize that nerve cells that release Antho-KAamide and Antho-RIamide are involved in the expansion phase of feeding behaviour in sea anemones. PMID:8397415

  11. The cnidarian-bilaterian ancestor possessed at least 56 homeoboxes: evidence from the starlet sea anemone, Nematostella vectensis

    PubMed Central

    Ryan, Joseph F; Burton, Patrick M; Mazza, Maureen E; Kwong, Grace K; Mullikin, James C; Finnerty, John R

    2006-01-01

    Background Homeodomain transcription factors are key components in the developmental toolkits of animals. While this gene superclass predates the evolutionary split between animals, plants, and fungi, many homeobox genes appear unique to animals. The origin of particular homeobox genes may, therefore, be associated with the evolution of particular animal traits. Here we report the first near-complete set of homeodomains from a basal (diploblastic) animal. Results Phylogenetic analyses were performed on 130 homeodomains from the sequenced genome of the sea anemone Nematostella vectensis along with 228 homeodomains from human and 97 homeodomains from Drosophila. The Nematostella homeodomains appear to be distributed among established homeodomain classes in the following fashion: 72 ANTP class; one HNF class; four LIM class; five POU class; 33 PRD class; five SINE class; and six TALE class. For four of the Nematostella homeodomains, there is disagreement between neighbor-joining and Bayesian trees regarding their class membership. A putative Nematostella CUT class gene is also identified. Conclusion The homeodomain superclass underwent extensive radiations prior to the evolutionary split between Cnidaria and Bilateria. Fifty-six homeodomain families found in human and/or fruit fly are also found in Nematostella, though seventeen families shared by human and fly appear absent in Nematostella. Homeodomain loss is also apparent in the bilaterian taxa: eight homeodomain families shared by Drosophila and Nematostella appear absent from human (CG13424, EMXLX, HOMEOBRAIN, MSXLX, NK7, REPO, ROUGH, and UNC4), and six homeodomain families shared by human and Nematostella appear absent from fruit fly (ALX, DMBX, DUX, HNF, POU1, and VAX). PMID:16867185

  12. Seasonal gametogenesis of host sea anemone ( Entacmaea quadricolor) inhabiting Hong Kong waters

    NASA Astrophysics Data System (ADS)

    Bi, Ying; Zhang, Bin; Zhang, Zhifeng; Qiu, Jianwen

    2015-02-01

    Studying gonadal development of annual cycle can reveal the process of gametogenesis and reproductive period, and evaluate fertility and source utilization of a species. Host sea anemones are conspicuous members of tropical and subtropical reef ecosystems, but little is known about its biology including reproductive seasonality. Here we reported a one-year study on the gametogenesis and reproduction of host sea anemone ( Entacmaea quadricolor) inhabiting Hong Kong waters. E. quadricolor tissues were sampled in 12 occasions from 5 m and 15 m depths of water, respectively. Histological sectioning of the tissues showed that E. quadricolor was dioecious, and populational ratio of female to male was 1:1.6. The gonadal development was asynchronous within an annual cycle, which included proliferating, growing, maturing, spawning, and resting stages. The spawning occurred between August and October when surface seawater temperature reached the annual maximum (28°C), suggesting that temperature is an important factor modulating the gonadal development and mature of E. quadricolor.

  13. Primary site and initial products of ammonium assimilation in the symbiotic sea anemone Anemonia viridis

    Microsoft Academic Search

    J. M. Roberts; P. S. Davies; L. M. Fixter; T. Preston

    1999-01-01

    Invertebrates containing endosymbiotic dinoflagellate algae (zooxanthellae) retain excretory nitrogen, and many are able\\u000a to take up ammonium from the surrounding seawater. However, the site of assimilation and role of nitrogen recycling between\\u000a symbiont and host remains unclear. In the present study, ammonium uptake by the symbiotic sea anemone Anemonia viridis (Forskål) was examined by following the pathway of assimilation using

  14. EVects of social organization on inter-clonal dominance relationships in the sea anemone Anthopleura elegantissima

    Microsoft Academic Search

    DAVID J. AYRE; RICHARD K. GROSBERG

    1996-01-01

    In the sea anemone Anthopleura elegantissima contact between non-clonemates often elicits inter-clonal fighting, involving the application of nematocyst-laden fighting tentacles (acrorhagi) and the locomotory retreat of losing polyps. This study confirms that isoclonal aggregations of A. elegan- tissima display an inducible polymorphism, such that polyps at the inter-clonal boundaries (warriors) are typically smaller and carry more fighting tentacles (acrorhagi) than

  15. Another bipolar deep-sea anemone: new species of Iosactis (Actiniaria, Endomyaria) from Antarctica

    NASA Astrophysics Data System (ADS)

    Rodríguez, Estefanía

    2012-06-01

    A new species of deep-sea burrowing sea anemone is described and illustrated from Antarctica. Iosactis antarctica sp. nov. is characterised by easily deciduous tentacles with sphincters in the base, smooth column, endodermal marginal sphincter, same mesenteries proximally and distally, 24 perfect mesenteries regularly arranged, diffuse retractor musculature and basilar muscles well developed. Iosactis antarctica sp. nov. is the second species of the deep-sea abyssal genus Iosactis; it differs from I. vagabunda in internal anatomy, cnidae and geographic distribution. The description of I. antarctica sp. nov. provides the opportunity to revaluate the morphology of the proximal end of this genus.

  16. Vertical and horizontal distribution patterns of the giant sea anemone Heteractis crispa with symbiotic anemonefish on a fringing coral reef

    Microsoft Academic Search

    Akihisa Hattori

    2006-01-01

    The distribution patterns of the leathery sea anemone, Heteractis crispa, which contains an algal endosymbiont (zooxanthellae) and anemonefish, were investigated in relation to size distribution on a shallow fringing reef (3.2 ha, 0–4 m depth) in Okinawa, Japan. Individual growth and movements were also examined. Large individuals (>1,000 cm2) inhabited reef edges up to a depth of 4 m, while small anemone (2)

  17. Tiny Sea Anemone from the Lower Cambrian of China

    PubMed Central

    Han, Jian; Kubota, Shin; Uchida, Hiro-omi; Stanley, George D.; Yao, Xiaoyong; Shu, Degan; Li, Yong; Yasui, Kinya

    2010-01-01

    Background Abundant fossils from the Ediacaran and Cambrian showing cnidarian grade grossly suggest that cnidarian diversification occurred earlier than that of other eumetazoans. However, fossils of possible soft-bodied polyps are scanty and modern corals are dated back only to the Middle Triassic, although molecular phylogenetic results support the idea that anthozoans represent the first major branch of the Cnidaria. Because of difficulties in taxonomic assignments owing to imperfect preservation of fossil cnidarian candidates, little is known about forms ancestral to those of living groups. Methods and Findings We have analyzed the soft-bodied polypoid microfossils Eolympia pediculata gen. et sp. nov. from the lowest Cambrian Kuanchuanpu Formation in southern China by scanning electron microscopy and computer-aided microtomography after isolating fossils from sedimentary rocks by acetic acid maceration. The fossils, about a half mm in body size, are preserved with 18 mesenteries including directives bilaterally arranged, 18 tentacles and a stalk-like pedicle. The pedicle suggests a sexual life cycle, while asexual reproduction by transverse fission also is inferred by circumferential grooves on the body column. Conclusions The features found in the present fossils fall within the morphological spectrum of modern Hexacorallia excluding Ceriantharia, and thus Eolympia pediculata could be a stem member for this group. The fossils also demonstrate that basic features characterizing modern hexacorallians such as bilateral symmetry and the reproductive system have deep roots in the Early Cambrian. PMID:20967244

  18. Evidence for participation of GCS1 in fertilization of the starlet sea anemone Nematostella vectensis: implication of a common mechanism of sperm-egg fusion in plants and animals.

    PubMed

    Ebchuqin, Eerdundagula; Yokota, Naoto; Yamada, Lixy; Yasuoka, Yuuri; Akasaka, Mari; Arakawa, Mio; Deguchi, Ryusaku; Mori, Toshiyuki; Sawada, Hitoshi

    2014-09-01

    It has been reported that GCS1 (Generative Cell Specific 1) is a transmembrane protein that is exclusively expressed in sperm cells and is essential for gamete fusion in flowering plants. The GCS1 gene is present not only in angiosperms but also in unicellular organisms and animals, implying the occurrence of a common or ancestral mechanism of GCS1-mediated gamete fusion. In order to elucidate the common mechanism, we investigated the role of GCS1 in animal fertilization using a sea anemone (Cnidaria), Nematostella vectensis. Although the existence of the GCS1 gene in N. vectensis has been reported, the expression of GCS1 in sperm and the role of GCS1 in fertilization are not known. In this study, we showed that the GCS1 gene is expressed in the testis and that GCS1 protein exists in sperm by in situ hybridization and proteomic analysis, respectively. Then we made four peptide antibodies against the N-terminal extracellular region of NvGCS1. These antibodies specifically reacted to NvGCS1 among sperm proteins on the basis of Western analysis and potently inhibited fertilization in a concentration-dependent manner. These results indicate that sperm GCS1 plays a pivotal role in fertilization, most probably in sperm-egg fusion, in a starlet sea anemone, suggesting a common gamete-fusion mechanism shared by eukaryotic organisms. PMID:25111819

  19. The role of L-Dopa in the nervous system of sea anemones: a putative inhibitory transmitter in tentacles

    PubMed

    Hudman; Mcfarlane

    1995-01-01

    1. l-Dopa evokes transitory inhibition of spontaneous contractions of tentacle longitudinal muscles in sea anemones. It also modulates spontaneous contractions of the sphincter muscle in isolated preparations and whole animals. 2. Extracellular recordings from the tentacles of Calliactis parasitica show that l-Dopa evokes bursts of electrical events apparently associated with a local nerve net. 3. We propose that l-Dopa be added to the growing list of putative transmitter substances in sea anemones, its action being to coordinate local inhibition of spontaneous tentacle contractions. PMID:9318857

  20. Asexual Propagation of Sea Anemones That Host Anemonefishes: Implications for the Marine Ornamental Aquarium Trade and Restocking Programs

    PubMed Central

    Scott, Anna; Hardefeldt, Jannah M.; Hall, Karina C.

    2014-01-01

    Anemonefishes and their host sea anemones form an iconic symbiotic association in reef environments, and are highly sought after in the marine aquarium trade. This study examines asexual propagation as a method for culturing a geographically widespread and commonly traded species of host sea anemone, Entacmaea quadricolor. Two experiments were done: the first to establish whether size or colour morph influenced survival after cutting into halves or quarters; and the second to see whether feeding was needed to maximise survival and growth after cutting. Survival rates were high in both experiments, with 89.3 and 93.8% of the anemones cut in half, and 62.5 and 80.4% cut in quarters surviving in experiments 1 and 2, respectively. Anemones that were cut in half were larger in size, and healed and grew quicker than those cut in quarters. However, even though survival was lower when the individuals were cut in quarters, this treatment produced the greatest number of anemones. Feeding increased oral disc diameter growth and reduced wet weight loss, but did not significantly influence pedal disc diameter. Given that the anemones took up to 56 d to form an off-centre mouth, it is highly likely that feeding may have produced greater effect if the experiment was run for longer. This low technology method of propagation could be used to produce individuals throughout the year and the anemones could then be used to supply the aquarium trade or restock depleted habitats, thus supporting biodiversity conservation in coral reef areas. PMID:25314131

  1. Abundance and diversity of anemonefishes and their host sea anemones at two mesophotic sites on the Great Barrier Reef, Australia

    NASA Astrophysics Data System (ADS)

    Bridge, T.; Scott, A.; Steinberg, D.

    2012-12-01

    Anemonefishes and their host sea anemones are iconic inhabitants of coral reef ecosystems. While studies have documented their abundance in shallow-water reef habitats in parts of the Indo-Pacific, none have examined these species on mesophotic reefs. In this study, we used autonomous underwater vehicle imagery to examine the abundance and diversity of anemones and anemonefishes at Viper Reef and Hydrographers Passage in the central Great Barrier Reef at depths between 50 and 65 m. A total of 37 host sea anemones (31 Entacmaea quadricolor and 6 Heteractis crispa) and 24 anemonefishes (23 Amphiprion akindynos and 1 A. perideraion) were observed. Densities were highest at Viper Reef, with 8.48 E. quadricolor and A. akindynos per 100 m2 of reef substratum. These results support the hypothesis that mesophotic reefs have many species common to shallow-water coral reefs and that many taxa may occur at depths greater than currently recognised.

  2. A muscle-specific transgenic reporter line of the sea anemone, Nematostella vectensis

    E-print Network

    Gibson, Matt

    ancestor of Cnidaria and Bilateria was genetically complex, and that much of that complexity has been- velopmental biology aimed at reconstructing the last common ancestor of Bilateria and Cnidaria and identifying

  3. Cnidarian Diversity Classes of Cnidaria

    E-print Network

    Cochran-Stafira, D. Liane

    1 Cnidarian Diversity Classes of Cnidaria · Anthozoa ­ Anemones and most corals · Scyphozoa ­ Jellyfish · Hydrozoa ­ Hydroids such as Hydra · Cubozoa ­ Cube jellies #12;2 Cnidarian Classes Anthozoa through asexual reproduction, such as budding or fission ­ Not followed by physical separation. ­ Zooids

  4. Atypical Reactive Center Kunitz-Type Inhibitor from the Sea Anemone Heteractis crispa

    PubMed Central

    Gladkikh, Irina; Monastyrnaya, Margarita; Leychenko, Elena; Zelepuga, Elena; Chausova, Victoria; Isaeva, Marina; Anastyuk, Stanislav; Andreev, Yaroslav; Peigneur, Steve; Tytgat, Jan; Kozlovkaya, Emma

    2012-01-01

    The primary structure of a new Kunitz-type protease inhibitor InhVJ from the sea anemone Heteractis crispa (Radianthus macrodactylus) was determined by protein sequencing and cDNA cloning. InhVJ amino acid sequence was shown to share high sequence identity (up to 98%) with the other known Kunitz-type sea anemones sequences. It was determined that the P1 Thr at the reactive site resulted in a decrease of the Ki of InhVJ to trypsin and ?-chymotrypsin (7.38 × 10?8 M and 9.93 × 10?7 M, respectively). By structure modeling the functional importance of amino acids at the reactive site as well as at the weak contact site were determined. The significant role of Glu45 for the orientation and stabilization of the InhVJ-trypsin complex was elucidated. We can suggest that there has been an adaptive evolution of the P1 residue at the inhibitor reactive site providing specialization or functional diversification of the paralogs. The appearance of a key so-called P1 Thr residue instead of Lys might lead to refinement of inhibitor specificity in the direction of subfamilies of serine proteases. The absence of Kv channel and TRPV1-receptor modulation activity was confirmed by electrophysiological screening tests. PMID:22851925

  5. Qualitative shift to indirect development in the parasitic sea anemone Edwardsiella lineata.

    PubMed

    Reitzel, Adam M; Sullivan, James C; Finnerty, John R

    2006-12-01

    Direct development lies at 1 end of a continuum that encompasses various degrees of indirect development. Indirect development exists where a larval stage is interposed between the embryo and the adult and undergoes metamorphosis, though the ecological and morphological distinctiveness of the larval stage relative to the adult stage can vary tremendously. There are numerous empirical examples where direct development has evolved from indirect development, but little empirical evidence describing a recent transition from direct to indirect development. Here, we suggest 4 criteria for defining indirect, and therefore metamorphic, life histories. We then apply these criteria to address the planula-polyp transition in cnidarians, focusing on 2 species in the anthozoan family Edwardsiidae. The lined sea anemone, Edwardsiella lineata, has made a qualitative shift towards indirect development that coincides with, and was potentially facilitated by, the evolution of endoparasitism. We compare E. lineata's development with that of a closely related sea anemone, Nematostella vectensis, where the nonfeeding planula gradually develops the morphology of the adult polyp. In E. lineata, a novel parasitic life history stage is interposed between the planula and the polyp. We discuss how the evolution of endoparasitism could facilitate the evolution metamorphic life histories. PMID:21672788

  6. *Metridium farcimen*, the valid name of a common North Pacific sea anemone (Cnidaria: Actiniaria: Acontiaria)

    E-print Network

    Fautin, Daphne G.; Hand, Cadet

    2000-12-01

    Three older names apply to the species described by Fautin et al. in 1990 as *Metridium giganteum*. They are *Actinia pripaus* Tilesius, 1809, *Actinia farcimen* Brandt, 1835, and *Isometridium rickettsi* Carlgren, 1949. ...

  7. Taxonomy and distribution of sea anemones (Cnidaria: Actiniaria, Corallimorpharia) from deep water of the northeastern Pacific

    E-print Network

    Eash-Loucks, Wendy Ellyn

    2010-12-10

    , and Fautin, 1999…………………………………….……………… …... 40 Paractinostola faeculenta (McMurrich, 1893)……………… ..…4 2 Sicyonis careyi n. sp. ..…………………………. ………… .…….4 7 Family Bathyphellidae Carlgren, 1932 Bathyphellia australis Dunn, 1983………………………… .…...5 7...…… …………………………………………………………………………..8 2 Conclusion.………………………………………………………………………………8 6 References ……………………………… ……………………………………………….8 7 Appendices…………………… ………………………… .………………………………9 4 Appendix 1 Abbreviations of Repositories....……… ………………………………9 4 4 Appendix 2 Type Status...

  8. Direct Monitoring of Intracellular Calcium Ions in Sea Anemone Tentacles Suggests Regulation of Nematocyst Discharge by Remote, Rare Epidermal Cells

    Microsoft Academic Search

    PATRICIA MIRE-THIBODEAUX; GLEN M. WATSON

    1993-01-01

    In tentacles of sea anemones, cnidocytes and adjacent supporting cells are believed to be independent receptor-effector complexes that regulate nematocyst dis- charge in response to exogenous N-acetylated sugars. When sugar chemoreceptors on supporting cells are ac- tivated, nematocyst discharge is two- to threefold greater than discharge without chemosensitization. To examine the role of Ca*+ as a second messenger in chemodetection

  9. Increased Cell Proliferation and Mucocyte Density in the Sea Anemone Aiptasia pallida Recovering from Bleaching

    PubMed Central

    Fransolet, David; Roberty, Stéphane; Herman, Anne-Catherine; Tonk, Linda; Hoegh-Guldberg, Ove; Plumier, Jean-Christophe

    2013-01-01

    Recovery of coral after bleaching episodes is a critical period for the health of the reef ecosystem. While events such as symbiont (genus Symbiodinium) shifting/shuffling or tissue apoptosis have been demonstrated to occur following bleaching, little is known concerning tissue recovery or cell proliferation. Here, we studied the sea anemone Aiptasia pallida exposed to a transient elevation of water temperature combined with high illumination (33°C and 1900 µmolphotons.m?2.s?1 for 30h). Following such treatment bleached anemones showed a significant reduction of their Symbiodinium density. Cell proliferation in the ectodermis and gastrodermis was determined by assessing the densities of cells labeled with a thymidine analogue (EdU). Cell proliferation significantly increased during the first day following stress in both tissue types. This increased cell proliferation returned to pre-stress values after one week. Although cell proliferation was higher in the ectodermis in absence of stress, it was relatively more pronounced in the gastrodermis of stressed anemones. In addition, the ratio of ectodermal mucocytes significantly increased three weeks after induced stress. These results suggest that thermal/photic stress coupled with the loss of the symbionts is able to enhance cell proliferation in both gastrodermis and ectodermis of cnidarians. While new cells formed in the gastrodermis are likely to host new Symbiodinium, the fate of new cells in the ectodermis was only partially revealed. Some new ectodermal cells may, in part, contribute to the increased number of mucocytes which could eventually help strengthen the heterotrophic state until restoration of the symbiosis. PMID:23724115

  10. Trace element profiles of the sea anemone Anemonia viridis living nearby a natural CO2 vent

    PubMed Central

    Borell, Esther M.; Fine, Maoz; Shaked, Yeala

    2014-01-01

    Ocean acidification (OA) is not an isolated threat, but acts in concert with other impacts on ecosystems and species. Coastal marine invertebrates will have to face the synergistic interactions of OA with other global and local stressors. One local factor, common in coastal environments, is trace element contamination. CO2 vent sites are extensively studied in the context of OA and are often considered analogous to the oceans in the next few decades. The CO2 vent found at Levante Bay (Vulcano, NE Sicily, Italy) also releases high concentrations of trace elements to its surrounding seawater, and is therefore a unique site to examine the effects of long-term exposure of nearby organisms to high pCO2 and trace element enrichment in situ. The sea anemone Anemonia viridis is prevalent next to the Vulcano vent and does not show signs of trace element poisoning/stress. The aim of our study was to compare A. viridis trace element profiles and compartmentalization between high pCO2 and control environments. Rather than examining whole anemone tissue, we analyzed two different body compartments—the pedal disc and the tentacles, and also examined the distribution of trace elements in the tentacles between the animal and the symbiotic algae. We found dramatic changes in trace element tissue concentrations between the high pCO2/high trace element and control sites, with strong accumulation of iron, lead, copper and cobalt, but decreased concentrations of cadmium, zinc and arsenic proximate to the vent. The pedal disc contained substantially more trace elements than the anemone’s tentacles, suggesting the pedal disc may serve as a detoxification/storage site for excess trace elements. Within the tentacles, the various trace elements displayed different partitioning patterns between animal tissue and algal symbionts. At both sites iron was found primarily in the algae, whereas cadmium, zinc and arsenic were primarily found in the animal tissue. Our data suggests that A. viridis regulates its internal trace element concentrations by compartmentalization and excretion and that these features contribute to its resilience and potential success at the trace element-rich high pCO2 vent. PMID:25250210

  11. Short Toxin-like Proteins Abound in Cnidaria Genomes

    PubMed Central

    Tirosh, Yitshak; Linial, Itai; Askenazi, Manor; Linial, Michal

    2012-01-01

    Cnidaria is a rich phylum that includes thousands of marine species. In this study, we focused on Anthozoa and Hydrozoa that are represented by the Nematostella vectensis (Sea anemone) and Hydra magnipapillata genomes. We present a method for ranking the toxin-like candidates from complete proteomes of Cnidaria. Toxin-like functions were revealed using ClanTox, a statistical machine-learning predictor trained on ion channel inhibitors from venomous animals. Fundamental features that were emphasized in training ClanTox include cysteines and their spacing along the sequences. Among the 83,000 proteins derived from Cnidaria representatives, we found 170 candidates that fulfill the properties of toxin-like-proteins, the vast majority of which were previously unrecognized as toxins. An additional 394 short proteins exhibit characteristics of toxin-like proteins at a moderate degree of confidence. Remarkably, only 11% of the predicted toxin-like proteins were previously classified as toxins. Based on our prediction methodology and manual annotation, we inferred functions for over 400 of these proteins. Such functions include protease inhibitors, membrane pore formation, ion channel blockers and metal binding proteins. Many of the proteins belong to small families of paralogs. We conclude that the evolutionary expansion of toxin-like proteins in Cnidaria contributes to their fitness in the complex environment of the aquatic ecosystem. PMID:23202321

  12. Force-dependent discharge of nematocysts in the sea anemone Haliplanella luciae (Verrill)

    PubMed Central

    Todaro, Dustin; Watson, Glen M.

    2012-01-01

    Summary Sea anemones discharge cnidae (‘stinging capsules’ including nematocysts) to capture prey and to defend themselves. In the present study, we tested the relationship between the force of test probes striking feeding tentacles and discharge of microbasic p-mastigophore nematocysts into the test probes. In seawater alone, the response curve is bimodal with maximal discharge observed at 0.33 and 1.10 millinewtons (mN) and with minimal discharge at 1.50?mN. Upon activating chemoreceptors for N-acetylated sugars, maximal discharge is observed across a broad range of smaller forces from 0.16 to 0.9?mN before decreasing to a minimum at 1.50?mN. Likewise, in the presence of nearby vibrations at key frequencies, maximal discharge is observed over a broad range of smaller forces before decreasing to a minimum at 1.50?mN. It appears that sensory input indicating proximity of potential prey expands the range of small forces of impact that stimulate maximal discharge (i.e. to less than 1.10?mN) but not at larger forces of impact (i.e. at approximately 1.50?mN). Thus, contact by small prey would stimulate maximal discharge, and all the more so if such contact is accompanied by specific odorants or by vibrations at specific frequencies. Nevertheless, anemones would not maximally discharge nematocysts into large animals that blunder into contact with their tentacles. PMID:23213451

  13. Isolation of sea anemones.

    PubMed

    Carstensen, K; McFarlane, I D; Rinehart, K L; Hudman, D; Sun, F; Grimmelikhuijzen, C J

    1993-01-01

    Using a radioimmunoassay against the C-terminal sequence Arg-Pro-NH2 (RPamide) we have isolated the neuropeptide sea anemone Anthopleura elegantissima. Addition of low concentrations of Antho-RPamide II to a tentacle preparation of sea anemones inhibited the spontaneous, rhythmic contractions, suggesting that the peptide is a neurotransmitter or neuromodulator. PMID:8483793

  14. Familial strife on the seashore: aggression increases with relatedness in the sea anemone Actinia equina.

    PubMed

    Foster, Nicola L; Briffa, Mark

    2014-03-01

    Pairwise contests occur when two individuals compete directly over ownership of an indivisible resource. Contests vary in the degree of escalation, some encounters being settled through non-injurious behaviour while others are only resolved after dangerous fighting. Here, we investigate the role of relatedness, assessed using AFLP analysis, on the occurrence of stinging during staged contests in the beadlet sea anemone Actinia equina. Contrary to our expectations, we found that the chance of stinging, and hence the chance of inflicting damage, increased with the degree of relatedness between the two opponents. This result may be explained by the negative relationship between asymmetry in fighting ability and escalation level predicted by theory. We suggest that in order to fully understand how relatedness influences aggression, predictions from kin selection theory should be incorporated with those from contest theory. PMID:24463009

  15. Computational Insights of the Interaction among Sea Anemones Neurotoxins and Kv1.3 Channel.

    PubMed

    Sabogal-Arango, Angélica; Barreto, George E; Ramírez-Sánchez, David; González-Mendoza, Juan; Barreto, Viviana; Morales, Ludis; González, Janneth

    2014-01-01

    Sea anemone neurotoxins are peptides that interact with Na(+) and K(+) channels, resulting in specific alterations on their functions. Some of these neurotoxins (1ROO, 1BGK, 2K9E, 1BEI) are important for the treatment of about 80 autoimmune disorders because of their specificity for Kv1.3 channel. The aim of this study was to identify the common residues among these neurotoxins by computational methods, and establish whether there is a pattern useful for the future generation of a treatment for autoimmune diseases. Our results showed eight new key common residues between the studied neurotoxins interacting with a histidine ring and the selectivity filter of the receptor, thus showing a possible pattern of interaction. This knowledge may serve as an input for the design of more promising drugs for autoimmune treatments. PMID:24812496

  16. Isolation of DNA, RNA and protein from the starlet sea anemone Nematostella vectensis.

    PubMed

    Stefanik, Derek J; Wolenski, Francis S; Friedman, Lauren E; Gilmore, Thomas D; Finnerty, John R

    2013-05-01

    Among marine invertebrates, the starlet sea anemone Nematostella vectensis has emerged as an important laboratory model system. One advantage of working with this species relative to many other marine invertebrates is the ease of isolating relatively pure DNA, RNA and protein. Nematostella can be raised at high densities, under clean culture conditions, and it lacks integumentary or skeletal structures that can impede the recovery of DNA, RNA or protein. Here we describe methods used in our lab to isolate DNA, RNA and protein from Nematostella embryos, larvae and adults. The methods described here are less expensive than commercial kits and are more easily scalable to larger tissue amounts. Preparation of DNA can be completed in ?7 h, RNA preparation in ?1.5 h and protein preparation in ?1 h. PMID:23579778

  17. Characterization of Circadian Behavior in the Starlet Sea Anemone, Nematostella vectensis

    PubMed Central

    Hendricks, William D.; Byrum, Christine A.; Meyer-Bernstein, Elizabeth L.

    2012-01-01

    Background Although much is known about how circadian systems control daily cycles in the physiology and behavior of Drosophila and several vertebrate models, marine invertebrates have often been overlooked in circadian rhythms research. This study focuses on the starlet sea anemone, Nematostella vectensis, a species that has received increasing attention within the scientific community for its potential as a model research organism. The recently sequenced genome of N. vectensis makes it an especially attractive model for exploring the molecular evolution of circadian behavior. Critical behavioral data needed to correlate gene expression patterns to specific behaviors are currently lacking in N. vectensis. Methodology/Principal Findings To detect the presence of behavioral oscillations in N. vectensis, locomotor activity was evaluated using an automated system in an environmentally controlled chamber. Animals exposed to a 24 hr photoperiod (12 hr light: 12 hr dark) exhibited locomotor behavior that was both rhythmic and predominantly nocturnal. The activity peak occurred in the early half of the night with a 2-fold increase in locomotion. Upon transfer to constant lighting conditions (constant light or constant dark), an approximately 24 hr rhythm persisted in most animals, suggesting that the rhythm is controlled by an endogenous circadian mechanism. Fourier analysis revealed the presence of multiple peaks in some animals suggesting additional rhythmic components could be present. In particular, an approximately 12 hr oscillation was often observed. The nocturnal increase in generalized locomotion corresponded to a 24 hr oscillation in animal elongation. Conclusions/Significance These data confirm the presence of a light-entrainable circadian clock in Nematostella vectensis. Additional components observed in some individuals indicate that an endogenous clock of approximately 12 hr frequency may also be present. By describing rhythmic locomotor behavior in N. vectensis, we have made important progress in developing the sea anemone as a model organism for circadian rhythm research. PMID:23056482

  18. Population impacts of collecting sea anemones and anemonefish for the marine aquarium trade in the Philippines

    NASA Astrophysics Data System (ADS)

    Shuman, Craig S.; Hodgson, Gregor; Ambrose, Richard F.

    2005-12-01

    Tropical marine ornamentals comprise an increasingly important fishery worldwide. Although the potential for overexploitation of marine ornamentals is great, few studies have addressed the population-level impacts of ornamental exploitation and few ornamental fisheries are managed. Analysis of catch records obtained from collectors over a four-month period in the vicinity of Cebu, Philippines, showed that anemonefish and anemones comprised close to 60% of the total catch. Underwater visual census surveys revealed that both anemone and anemonefish densities were significantly lower in exploited areas than in protected areas. The low density of anemones on exploited reefs accounted for over 80% of the reduced density of anemonefish at those sites. There were similar numbers of anemonefish per unit area of anemone in protected and exploited sites; however, biomass of anemonefish per unit area of anemone was lower in exploited areas. Reduction of anemone removals is recommended to support the sustainable harvest of anemonefish from this region.

  19. Introduction to Cnidaria

    NSDL National Science Digital Library

    In depth site covers Cnidarian life history, ecology, morphology, systematics, and fossil record. Organisms described include corals, anemones, sea pens, box jellies, siphonophores, hydroids, fire corals, medusae, and true jellyfish. Nice explanations, diagrams, and photos.

  20. Modulation of neuronal sodium channels by the sea anemone peptide BDS-I

    PubMed Central

    Liu, Pin; Jo, Sooyeon

    2012-01-01

    Blood-depressing substance I (BDS-I), a 43 amino-acid peptide from sea anemone venom, is used as a specific inhibitor of Kv3-family potassium channels. We found that BDS-I acts with even higher potency to modulate specific types of voltage-dependent sodium channels. In rat dorsal root ganglion (DRG) neurons, 3 ?M BDS-I strongly enhanced tetrodotoxin (TTX)-sensitive sodium current but weakly inhibited TTX-resistant sodium current. In rat superior cervical ganglion (SCG) neurons, which express only TTX-sensitive sodium current, BDS-I enhanced current elicited by small depolarizations and slowed decay of currents at all voltages (EC50 ? 300 nM). BDS-I acted with exceptionally high potency and efficacy on cloned human Nav1.7 channels, slowing inactivation by 6-fold, with an EC50 of approximately 3 nM. BDS-I also slowed inactivation of sodium currents in N1E-115 neuroblastoma cells (mainly from Nav1.3 channels), with an EC50 ? 600 nM. In hippocampal CA3 pyramidal neurons (mouse) and cerebellar Purkinje neurons (mouse and rat), BDS-I had only small effects on current decay (slowing inactivation by 20–50%), suggesting relatively weak sensitivity of Nav1.1 and Nav1.6 channels. The biggest effect of BDS-I in central neurons was to enhance resurgent current in Purkinje neurons, an effect reflected in enhancement of sodium current during the repolarization phase of Purkinje neuron action potentials. Overall, these results show that BDS-I acts to modulate sodium channel gating in a manner similar to previously known neurotoxin receptor site 3 anemone toxins but with different isoform sensitivity. Most notably, BDS-I acts with very high potency on human Nav1.7 channels. PMID:22442564

  1. Anemone at the California rocky intertidal zone

    NSDL National Science Digital Library

    Katie Hale (California State University, Fullerton; Student, Biological Sciences)

    2007-01-04

    Anemones are carnivores and use their tentacles to move food into their mouths. Their tentacles contain stinging cells to kill prey. Sea anemones attach to rocks in lower and middle intertidal zones and are vulnerable to drying out.

  2. Lipid composition of beef brain, beef liver, and the sea anemone: Two approaches to quantitative fractionation of complex lipid mixtures

    Microsoft Academic Search

    George Rouser; Gene Kritchevsky; Dorothy Heller; Ellen Lieber

    1963-01-01

    Two new schemes for fractionation of complex lipid mixtures are presented. Their use for the study of lipids of beef brain,\\u000a beef liver, and the sea anemone are described. Apparatus and techniques for working in an inert atmosphere, evaporation of\\u000a solutions in the cold under nitrogen, use of infrared spectroscopy for examination of lipids and their hydrolysis products,\\u000a preparation and

  3. Changes of cellular superficial configuration of symbiotic algae during cultivation from two anemones found in the South China Sea

    Microsoft Academic Search

    Baohua Zhu; Kehou Pan; Guangce Wang

    2008-01-01

    Symbiotic algae from two anemones, Radianthus macrodactylus and Stichodactyla mertensii, found in the South China Sea, were cultivated in ASP-8A medium in this study. Changes of superficial configuration of symbiotic\\u000a algae during the cultivation were studied by means of a microscope and a scanning electron microscope (SEM). A number of small\\u000a cavities appeared on the surfaces of symbiotic algae after

  4. Reproductive biology of the sea anemone shrimp Periclimenes rathbunae (Caridea, Palaemonidae, Pontoniinae), from the Caribbean coast of Costa Rica

    PubMed Central

    Azofeifa-Solano, Juan Carlos; Elizondo-Coto, Marcelo; Wehrtmann, Ingo S.

    2014-01-01

    Abstract Caridean shrimps are a highly diverse group and many species form symbiotic relationships with different marine invertebrates. Periclimenes rathbunae is a brightly colored shrimp that lives predominantly in association with sea anemones. Information about the reproductive ecology of the species is scarce. Therefore, we collected 70 ovigerous females inhabiting the sun sea anemone Stichodactyla helianthus in coral reefs from the southern Caribbean coast of Costa Rica. Females produced on average 289 ± 120 embryos. The volume of recently-produced embryos was on average 0.038 mm3, and embryo volume increased by 192% during the incubation period. The average embryo mortality during embryogenesis was 24%. The reproductive output was 0.24 ± 0.094, considerably higher than in many other pontoniine shrimps. Females carrying embryos close to hatching showed fully developed ovaries, suggesting consecutive spawning. We assume that the sheltered habitat, living on sea anemones, allows Periclimenes rathbunae to allocate more energy in embryo production than most other free-living caridean shrimps. This is the first record of Periclimenes rathbunae for Costa Rica. PMID:25561838

  5. Algal genotype and photoacclimatory responses of the symbiotic alga Symbiodinium in natural populations of the sea anemone Anemonia viridis

    PubMed Central

    Bythell, J. C.; Douglas, A. E.; Sharp, V. A.; Searle, J. B.; Brown, B. E.

    1997-01-01

    As an approach to investigate the impact of solar radiation on an alga–invertebrate symbiosis, the genetic variation and photosynthetic responses of the dinoflagellate algal symbiosis in an intertidal and a subtidal population of the sea anemone Anemonia viridis were explored. Allozyme analysis of the anemones indicated that the two populations were genetically very similar, with a Nei's index value of genetic identity (I) of 0.998. The algae in all animals examined were identified as Symbiodinium of clade a by PCR-RFLP analysis of the small subunit ribosomal RNA gene. The symbiosis in the two populations did not differ significantly in algal population density, chlorophyll a content per algal cell or any photosynthetic parameter obtained from studies of the relationship between photosynthesis and irradiance. We conclude that there is not necessarily genetic variation or photosynthetic plasticity of the symbiotic algae in Anemonia viridis inhabiting environments characterized by the different solar irradiances of the subtidal and intertidal habitats.

  6. Sexual Plasticity and Self-Fertilization in the Sea Anemone Aiptasia diaphana

    PubMed Central

    Schlesinger, Ami; Kramarsky-Winter, Esti; Rosenfeld, Hanna; Armoza-Zvoloni, Rachel; Loya, Yossi

    2010-01-01

    Traits that influence reproductive success and contribute to reproductive isolation in animal and plant populations are a central focus of evolutionary biology. In the present study we used an experimental approach to demonstrate the occurrence of environmental effects on sexual and asexual reproduction, and provide evidence for sexual plasticity and inter-clonal fertilization in laboratory-cultured lines of the sea anemone Aiptasia diaphana. We showed that in A. diaphana, both asexual reproduction by pedal laceration, and sexual reproduction have seasonal components. The rate of pedal laceration was ten-fold higher under summer photoperiod and water temperature conditions than under winter conditions. The onset of gametogenesis coincided with the rising water temperatures occurring in spring, and spawning occurred under parameters that emulated summer photoperiod and temperature conditions. In addition, we showed that under laboratory conditions, asexually produced clones derived from a single founder individual exhibit sexual plasticity, resulting in the development of both male and female individuals. Moreover, a single female founder produced not only males and females but also hermaphrodite individuals. We further demonstrated that A. diaphana can fertilize within and between clone lines, producing swimming planula larvae. These diverse reproductive strategies may explain the species success as invader of artificial marine substrates. We suggest that these diverse reproductive strategies, together with their unique evolutionary position, make Aiptasia diaphana an excellent model for studying the evolution of sex. PMID:20686700

  7. Mercury distribution, methylation and volatilization in microcosms with and without the sea anemone Bunodosoma caissarum.

    PubMed

    Rizzini Ansari, Nafisa; Correia, Raquel Rose Silva; Fernandez, Marcos Antônio; Cordeiro, Renato Campello; Guimarães, Jean Remy Davée

    2015-03-15

    Mercury (Hg) has a complex biogeochemical cycle in aquatic environments. Its most toxic form, methylmercury (MeHg), is produced by microorganisms. This study investigated how the sea anemone Bunodosoma caissarum affects Hg distribution, methylation and volatilization in laboratory model systems. (203)Hg was added to microcosms and its distribution in seawater, specimens and air was periodically measured by gamma spectrometry. MeHg was measured by liquid scintillation. After the uptake period, specimens had a bioconcentration factor of 70 and in microcosms with and without B. caissarum, respectively 0.05% and 0.32% of the initial spike was found as MeHg. After depuration, MeHg in specimens ranged from 0.2% to 2.4% of total Hg. Microcosms with B. caissarum had higher Hg volatilization (58%) than controls (17%), possibly due to Hg(2+) reduction mediated by microorganisms associated with its tissues and mucus secretions. Marine organisms and their associated microbiota may play a role in Hg and MeHg cycling. PMID:25599628

  8. Sexual plasticity and self-fertilization in the sea anemone Aiptasia diaphana.

    PubMed

    Schlesinger, Ami; Kramarsky-Winter, Esti; Rosenfeld, Hanna; Armoza-Zvoloni, Rachel; Loya, Yossi

    2010-01-01

    Traits that influence reproductive success and contribute to reproductive isolation in animal and plant populations are a central focus of evolutionary biology. In the present study we used an experimental approach to demonstrate the occurrence of environmental effects on sexual and asexual reproduction, and provide evidence for sexual plasticity and inter-clonal fertilization in laboratory-cultured lines of the sea anemone Aiptasia diaphana. We showed that in A. diaphana, both asexual reproduction by pedal laceration, and sexual reproduction have seasonal components. The rate of pedal laceration was ten-fold higher under summer photoperiod and water temperature conditions than under winter conditions. The onset of gametogenesis coincided with the rising water temperatures occurring in spring, and spawning occurred under parameters that emulated summer photoperiod and temperature conditions. In addition, we showed that under laboratory conditions, asexually produced clones derived from a single founder individual exhibit sexual plasticity, resulting in the development of both male and female individuals. Moreover, a single female founder produced not only males and females but also hermaphrodite individuals. We further demonstrated that A. diaphana can fertilize within and between clone lines, producing swimming planula larvae. These diverse reproductive strategies may explain the species success as invader of artificial marine substrates. We suggest that these diverse reproductive strategies, together with their unique evolutionary position, make Aiptasia diaphana an excellent model for studying the evolution of sex. PMID:20686700

  9. Unexpected complexity of the Wnt gene family in a sea anemone.

    PubMed

    Kusserow, Arne; Pang, Kevin; Sturm, Carsten; Hrouda, Martina; Lentfer, Jan; Schmidt, Heiko A; Technau, Ulrich; von Haeseler, Arndt; Hobmayer, Bert; Martindale, Mark Q; Holstein, Thomas W

    2005-01-13

    The Wnt gene family encodes secreted signalling molecules that control cell fate in animal development and human diseases. Despite its significance, the evolution of this metazoan-specific protein family is unclear. In vertebrates, twelve Wnt subfamilies were defined, of which only six have counterparts in Ecdysozoa (for example, Drosophila and Caenorhabditis). Here, we report the isolation of twelve Wnt genes from the sea anemone Nematostella vectensis, a species representing the basal group within cnidarians. Cnidarians are diploblastic animals and the sister-group to bilaterian metazoans. Phylogenetic analyses of N. vectensis Wnt genes reveal a thus far unpredicted ancestral diversity within the Wnt family. Cnidarians and bilaterians have at least eleven of the twelve known Wnt gene subfamilies in common; five subfamilies appear to be lost in the protostome lineage. Expression patterns of Wnt genes during N. vectensis embryogenesis indicate distinct roles of Wnts in gastrulation, resulting in serial overlapping expression domains along the primary axis of the planula larva. This unexpectedly complex inventory of Wnt family signalling factors evolved in early multi-cellular animals about 650 million years (Myr) ago, predating the Cambrian explosion by at least 100 Myr (refs 5, 8). It emphasizes the crucial function of Wnt genes in the diversification of eumetazoan body plans. PMID:15650739

  10. Hct-A Is a New Actinoporin Family from the Heteractis Crispa Sea Anemone

    PubMed Central

    Leichenko, E. V.; Monastirnaya, M. M.; Zelepuga, E. A.; Tkacheva, E. S.; Isaeva, M. P.; Likhatskaya, G. N.; Anastyuk, S. D.; Kozlovskaya, E. P.

    2014-01-01

    Several new actinoporin isoforms with molecular weights of 18995.5 to 19398.7 Da exhibiting a high hemolytic activity were isolated from the tropical sea anemone Heteractis crispa using a combination of liquid chromatography techniques. The actinoporins were demonstrated to occur as mono-, di-, and trimers in aqueous solutions. The sequences of the genes encoding actinoporins were identified, and the amino acid sequences of the new polypeptides belonging to the Hct-A actinoporin family were obtained. The new acinoporins differ in their isoelectric points, the number and localization of charged amino acid residues at the functionally important N-terminal fragment of the molecule, as well as in the charge of a tetrapeptide (amino acid residues 74–77) involved in an electrostatic interaction with the cytoplasmic membrane. A recombinant actinoporin, rHct-A2, with a molecular weight of 19141 Da, pI of 9.64, and hemolytic activity of 4.0 × 104 HU/mg, was obtained. The conductivity of the ion channels formed by rHct-A2 in the BLM was demonstrated to be similar to that of the native actinoporin from H. crispa. The obtained data expand knowledge on the structural and functional relationships of actinoporins and contribute to our understanding of the functioning mechanism of these molecules, which is the basis for the development of compounds with a high biomedical potential. Currently, they are considered as models for obtaining antitumor, antibacterial, and cardiac-stimulating agents. PMID:25558399

  11. Interactions between the tropical sea anemone Aiptasia pallida and Serratia marcescens, an opportunistic pathogen of corals.

    PubMed

    Krediet, Cory J; Meyer, Julie L; Gimbrone, Nicholas; Yanong, Roy; Berzins, Ilze; Alagely, Ali; Castro, Herman; Ritchie, Kim B; Paul, Valerie J; Teplitski, Max

    2014-06-01

    Coral reefs are under increasing stress caused by global and local environmental changes, which are thought to increase the susceptibility of corals to opportunistic pathogens. In the absence of an easily culturable model animal, the understanding of the mechanisms of disease progression in corals remains fairly limited. In the present study, we tested the susceptibility of the tropical sea anemone Aiptasia pallida to an opportunistic coral pathogen (Serratia marcescens). A.?pallida was susceptible to S. marcescens?PDL100 and responded to this opportunistic coral pathogen with darkening of the tissues and retraction of tentacles, followed by complete disintegration of polyp tissues. Histological observations revealed loss of zooxanthellae and structural changes in eosinophilic granular cells in response to pathogen infection. A screen of S.?marcescens mutants identified a motility and tetrathionate reductase mutants as defective in virulence in the A.?pallida infection model. In co-infections with the wild-type strain, the tetrathionate reductase mutant was less fit within the surface mucopolysaccharide layer of the host coral Acropora palmata. PMID:24983533

  12. Development of a sea anemone toxin as an immunomodulator for therapy of autoimmune diseases

    PubMed Central

    Chi, Victor; Pennington, Michael W.; Norton, Raymond S.; Tarcha, Eric; Londono, Luz; Sims-Fahey, Brian; Upadhyay, Sanjeev K.; Lakey, Jonathan T.; Iadonato, Shawn; Wulff, Heike; Beeton, Christine; Chandy, K. George

    2012-01-01

    Electrophysiological and pharmacological studies coupled with molecular identification have revealed a unique network of ion channels—Kv1.3, KCa3.1, CRAC (Orai1 + Stim1), TRPM7, Clswell—in lymphocytes that initiates and maintains the calcium signaling cascade required for activation. The expression pattern of these channels changes during lymphocyte activation and differentiation, allowing the functional network to adapt during an immune response. The Kv1.3 channel is of interest because it plays a critical role in subsets of T and B lymphocytes implicated in autoimmune disorders. The ShK toxin from the sea anemone Stichodactyla helianthus is a potent blocker of Kv1.3. ShK-186, a synthetic analog of ShK, is being developed as a therapeutic for autoimmune diseases, and is scheduled to begin first-in-man phase-1 trials in 2011. This review describes the journey that has led to the development of ShK-186. PMID:21867724

  13. Fast Neurotransmission Related Genes Are Expressed in Non Nervous Endoderm in the Sea Anemone Nematostella vectensis

    PubMed Central

    Oren, Matan; Brikner, Itzchak; Appelbaum, Lior; Levy, Oren

    2014-01-01

    Cnidarian nervous systems utilize chemical transmission to transfer signals through synapses and neurons. To date, ample evidence has been accumulated for the participation of neuropeptides, primarily RFamides, in neurotransmission. Yet, it is still not clear if this is the case for the classical fast neurotransmitters such as GABA, Glutamate, Acetylcholine and Monoamines. A large repertoire of cnidarian Fast Neurotransmitter related Genes (FNGs) has been recently identified in the genome of the sea anemone, Nematostella vectensis. In order to test whether FNGs are localized in cnidarian neurons, we characterized the expression patterns of eight Nematostella genes that are closely or distantly related to human central and peripheral nervous systems genes, in adult Nematostella and compared them to the RFamide localization. Our results show common expression patterns for all tested genes, in a single endodermal cell layer. These expressions did not correspond with the RFamide expressing nerve cell network. Following these results we suggest that the tested Nematostella genes may not be directly involved in vertebrate-like fast neurotransmission. PMID:24705400

  14. Fatty Acid and Phospholipid Syntheses Are Prerequisites for the Cell Cycle of Symbiodinium and Their Endosymbiosis within Sea Anemones

    PubMed Central

    Wang, Li-Hsueh; Lee, Hsieh-He; Fang, Lee-Shing; Mayfield, Anderson B.; Chen, Chii-Shiarng

    2013-01-01

    Lipids are a source of metabolic energy, as well as essential components of cellular membranes. Although they have been shown to be key players in the regulation of cell proliferation in various eukaryotes, including microalgae, their role in the cell cycle of cnidarian-dinoflagellate (genus Symbiodinium) endosymbioses remains to be elucidated. The present study examined the effects of a lipid synthesis inhibitor, cerulenin, on the cell cycle of both cultured Symbiodinium (clade B) and those engaged in an endosymbiotic association with the sea anemone Aiptasia pulchella. In the former, cerulenin exposure was found to inhibit free fatty acid (FFA) synthesis, as it does in other organisms. Additionally, while it also significantly inhibited the synthesis of phosphatidylethanolamine (PE), it did not affect the production of sterol ester (SE) or phosphatidylcholine (PC). Interestingly, cerulenin also significantly retarded cell division by arresting the cell cycles at the G0/G1 phase. Cerulenin-treated Symbiodinium were found to be taken up by anemone hosts at a significantly depressed quantity in comparison with control Symbiodinium. Furthermore, the uptake of cerulenin-treated Symbiodinium in host tentacles occurred much more slowly than in untreated controls. These results indicate that FFA and PE may play critical roles in the recognition, proliferation, and ultimately the success of endosymbiosis with anemones. PMID:24009685

  15. Phospholipase A2 in cnidaria.

    PubMed

    Nevalainen, Timo J; Peuravuori, Heikki J; Quinn, Ronald J; Llewellyn, Lyndon E; Benzie, John A H; Fenner, Peter J; Winkel, Ken D

    2004-12-01

    Phospholipase A2 (PLA2) is an enzyme present in snake and other venoms and body fluids. We measured PLA2 catalytic activity in tissue homogenates of 22 species representing the classes Anthozoa, Hydrozoa, Scyphozoa and Cubozoa of the phylum Cnidaria. High PLA2 levels were found in the hydrozoan fire coral Millepora sp. (median 735 U/g protein) and the stony coral Pocillopora damicornis (693 U/g) that cause skin irritation upon contact. High levels of PLA2 activity were also found in the acontia of the sea anemone Adamsia carciniopados (293 U/g). Acontia are long threads containing nematocysts and are used in defense and aggression by the animal. Tentacles of scyphozoan and cubozoan species had high PLA2 activity levels: those of the multitentacled box jellyfish Chironex fleckeri contained 184 U/g PLA2 activity. The functions of cnidarian PLA2 may include roles in the capture and digestion of prey and defense of the animal. The current observations support the idea that cnidarian PLA2 may participate in the sting site irritation and systemic envenomation syndrome resulting from contact with cnidarians. PMID:15581805

  16. Changes of cellular superficial configuration of symbiotic algae during cultivation from two anemones found in the South China Sea

    NASA Astrophysics Data System (ADS)

    Zhu, Baohua; Pan, Kehou; Wang, Guangce

    2008-02-01

    Symbiotic algae from two anemones, Radianthus macrodactylus and Stichodactyla mertensii, found in the South China Sea, were cultivated in ASP-8A medium in this study. Changes of superficial configuration of symbiotic algae during the cultivation were studied by means of a microscope and a scanning electron microscope (SEM). A number of small cavities appeared on the surfaces of symbiotic algae after they were cultivated for 10 h. The cavities enlarged and the cell contents were lost with extended cultivation. Our data suggested that the presence of cavities on symbiotic algae surfaces may be one of the main reasons for failure to culture symbiotic algae in an artificial medium.

  17. Identification of hemolytic and neuroactive fractions in the venom of the sea anemone Bunodosoma cangicum.

    PubMed

    Lagos, P; Duran, R; Cerveñansky, C; Freitas, J C; Silveira, R

    2001-07-01

    Sea anemones are a rich source of biologically active substances. In crayfish muscle fibers, Bunodosoma cangicum whole venom selectively blocks the I K(Ca) currents. In the present study, we report for the first time powerful hemolytic and neuroactive effects present in two different fractions obtained by gel-filtration chromatography from whole venom of B. cangicum. A cytolytic fraction (Bcg-2) with components of molecular mass ranging from 8 to 18 kDa elicited hemolysis of mouse erythrocytes with an EC50 = 14 microg/ml and a maximum dose of 22 microg/ml. The effects of the neuroactive fraction, Bcg-3 (2 to 5 kDa), were studied on isolated crab nerves. This fraction prolonged the compound action potentials by increasing their duration and rise time in a dose-dependent manner. This effect was evident after the washout of the preparation, suggesting the existence of a reversible substance that was initially masking the effects of an irreversible one. In order to elucidate the target of Bcg-3 action, the fraction was applied to a tetraethylammonium-pretreated preparation. An additional increase in action potential duration was observed, suggesting a blockade of a different population of K+ channels or of tetraethylammonium-insensitive channels. Also, tetrodotoxin could not block the action potentials in a Bcg-3-pretreated preparation, suggesting a possible interaction of Bcg-3 with Na+ channels. The present data suggest that B. cangicum venom contains at least two bioactive fractions whose activity on cell membranes seems to differ from the I K(Ca) blockade described previously. PMID:11449308

  18. Comparative anatomy and histology of developmental and parasitic stages in the life cycle of the lined sea anemone Edwardsiella lineata.

    PubMed

    Reitzel, Adam M; Daly, Marymegan; Sullivan, James C; Finnerty, John R

    2009-02-01

    The evolution of parasitism is often accompanied by profound changes to the developmental program. However, relatively few studies have directly examined the developmental evolution of parasitic species from free-living ancestors. The lined sea anemone Edwardsiella lineata is a relatively recently evolved parasite for which closely related free-living outgroups are known, including the starlet sea anemone Nematostella vectensis. The larva of E. lineata parasitizes the ctenophore Mnemiopsis leidyi, and, once embedded in its host, the anemone assumes a novel vermiform body plan. That we might begin to understand how the developmental program of this species has been transformed during the evolution of parasitism, we characterized the gross anatomy, histology, and cnidom of the parasitic stage, post-parasitic larval stage, and adult stage of the E. lineata life cycle. The distinct parasitic stage of the life cycle differs from the post-parasitic larva with respect to overall shape, external ciliation, cnida frequency, and tissue architecture. The parasitic stage and planula both contain holotrichs, a type of cnida not previously reported in Edwardsiidae. The internal morphology of the post-parasitic planula is extremely similar to the adult morphology, with a complete set of mesenterial tissue and musculature despite this stage having little external differentiation. Finally, we observed 2 previously undocumented aspects of asexual reproduction in E. lineata: (1) the parasitic stage undergoes transverse fission via physal pinching, the first report of asexual reproduction in a pre-adult stage in the Edwardsiidae; and (2) the juvenile polyp undergoes transverse fission via polarity reversal, the first time this form of fission has been reported in E. lineata. PMID:18656992

  19. Comparison of developmental trajectories in the starlet sea anemone Nematostella vectensis: embryogenesis, regeneration,

    E-print Network

    Finnerty, John R.

    to the Atlantic coast of North America. In recent years, this anemone has emerged as a model system in cnidarian reproduction, (2) asexual reproduction via physal pinching, (3) asexual reproduction via polarity reversal many cnidarians, N. vectensis can undergo multiple developmental trajectories, i.e., the adult polyp

  20. From Sea Anemone to Homo Sapiens: The Evolution of the p53 Family of Genes

    SciTech Connect

    Levine, Arnold (Institute for Advanced Study) [Institute for Advanced Study

    2009-09-14

    The human genome contains three transcription factors termed p53, p63 and p73 which are related orthologues. The function of the p53 protein is to respond to a wide variety of stresses which can disrupt the fidelity of DNA replication and cell division in somatic cells of the body. These stress signals, such as DNA damage, increase the mutation rate during DNA duplication and so an active p53 protein responds by eliminating clones of cells with mutations employing apoptosis, senescence or cell cycle arrest. In this way the p53 protein acts as a tumor suppressor preventing the mutations that can lead to cancers. The p63 and p73 proteins act in a similar fashion to protect the germ line cells in females (eggs). In addition the p63 protein plays a central role in the formation of epithelial cell layers and p73 plays a critical role in the formation of several structures in the central nervous system. Based upon their amino acid sequences and structural considerations the oldest organisms that contain an ancestor of the p53/p63/p73 gene are the sea anemone or hydra. The present day representatives of these animals contain a p63/p73 like ancestor gene and the protein functions in germ cells of this animal to enforce the fidelity of DNA replication after exposure to ultraviolet light. Thus the structure and functions of this gene family have been preserved for over one billion years of evolution. Other invertebrates such as the worm, the fly and the clam contain a very similar ancestor gene with a similar set of functions. The withdrawal of a food source from a worm results in the p63/p73 mediated apoptosis of the eggs so that new organisms will not be hatched into a poor environment. A similar response is thought to occur in humans. Thus this ancestor gene ensures the fidelity of the next generation of organisms. The first time a clearly distinct new p53 gene arises is in the cartilaginous fish and in the bony fish a separation of the p

  1. Trioecy, a unique breeding strategy in the sea anemone Aiptasia diaphana and its association with sex steroids.

    PubMed

    Armoza-Zvuloni, Rachel; Kramarsky-Winter, Esti; Loya, Yossi; Schlesinger, Ami; Rosenfeld, Hanna

    2014-06-01

    Reproductive development of anthozoans reveals wide range of breeding strategies. Here, we report the occurrence of trioecy in the sea anemone Aiptasia diaphana (co-occurrence of males, females, and hermaphrodites), which so far was well documented only in plants. Age-homogeneous populations were obtained from pedal lacerates (asexual propagules) and cultured under control conditions. Careful documentation of growth, gamete morphology, and vertebrate-like steroid (i.e., progesterone, testosterone, and estradiol) levels were carried out over a 9-wk period between 4 and 12 wk postlaceration (wpl). First phenotypic signs of gametes development were observed in 6-wk-old anemones, pointing to the differentiation of males and hermaphrodites. While the males exhibited cellular progression of spermatogenesis, the hermaphrodites underwent a process of sex allocation, giving rise to male, female, and hermaphrodite phenotypes. Testosterone levels were relatively high prior to gamete appearance (4 wpl) and later on during gamete maturation (10 wpl). Conversely, estradiol levels steadily increased from 6 to 10 wpl, reaching their peak concomitant with oocyte maturation. Interestingly, increased oocyte atresia incidences were recorded during 9-12 wpl, coinciding with declining levels of steroid hormones. These results point to a strong similarity between the activity of sex steroids in vertebrates and that of vertebrate-like sex steroids on critical stages of A. diaphana's sexual differentiation and gametogenic cycle. The reproductive characteristics of A. diaphana make this anthozoan an important model species for the study of evolutionary drivers and processes underlying sexual development. PMID:24790160

  2. Ancient origins of axial patterning genes: Hox genes and ParaHox genes in the Cnidaria.

    PubMed

    Finnerty, J R; Martindale, M Q

    1999-01-01

    Among the bilaterally symmetrical, triploblastic animals (the Bilateria), a conserved set of developmental regulatory genes are known to function in patterning the anterior-posterior (AP) axis. This set includes the well-studied Hox cluster genes, and the recently described genes of the ParaHox cluster, which is believed to be the evolutionary sister of the Hox cluster (Brooke et al. 1998). The conserved role of these axial patterning genes in animals as diverse as frogs and flies is believed to reflect an underlying homology (i.e., all bilaterians derive from a common ancestor which possessed an AP axis and the developmental mechanisms responsible for patterning the axis). However, the origin and early evolution of Hox genes and ParaHox genes remain obscure. Repeated attempts have been made to reconstruct the early evolution of Hox genes by analyzing data from the triphoblastic animals, the Bilateria (Schubert et al. 1993; Zhang and Nei 1996). A more precise dating of Hox origins has been elusive due to a lack of sufficient information from outgroup taxa such as the phylum Cnidaria (corals, hydras, jellyfishes, and sea anemones). In combination with outgroup taxa, another potential source of information about Hox origins is outgroup genes (e.g., the genes of the ParaHox cluster). In this article, we present cDNA sequences of two Hox-like genes (anthox2 and anthox6) from the sea anemone, Nematostella vectensis. Phylogenetic analysis indicates that anthox2 (= Cnox2) is homologous to the GSX class of ParaHox genes, and anthox6 is homologous to the anterior class of Hox genes. Therefore, the origin of Hox genes and ParaHox genes occurred prior to the evolutionary split between the Cnidaria and the Bilateria and predated the evolution of the anterior-posterior axis of bilaterian animals. Our analysis also suggests that the central Hox class was invented in the bilaterian lineage, subsequent to their split from the Cnidaria. PMID:11324016

  3. Proton nuclear magnetic resonance study of the antihypertensive and antiviral protein BDS-I from the sea anemone Anemonia sulcata: Sequential and stereospecific resonance assignment and secondary structure

    Microsoft Academic Search

    Paul C. Driscoll; G. Marius Clore; Laszlo Beress; Angela M. Gronenborn

    1989-01-01

    The sequential resonance assignment of the ¹H NMR spectrum of the antihypertensive and antiviral protein BDS-I from the sea anemone Anemonia sulcata is presented. This is carried out with two-dimensional NMR techniques to identify through-bond and through-space (< 5â«) connectivities. Added spectral complexity arises from the fact that the sample is an approximately 1:1 mixture of two BDS-I isoproteins, (Leu-18)-BDS-I

  4. The Smallest Oocytes among Broadcast-Spawning Actiniarians and a Unique Lunar Reproductive Cycle in a Unisexual Population of the Sea Anemone, Aiptasia pulchella (Anthozoa: Actiniaria)

    Microsoft Academic Search

    Chienhsun Chen; Keryea Soong; Chaolun Allen Chen

    2008-01-01

    Chienhsun Chen, Keryea Soong, and Chaolun Allen Chen (2008) The smallest oocytes among broadcast- spawning actiniarians and a unique lunar reproductive cycle in a unisexual population of the sea anemone, Aiptasia pulchella (Anthozoa: Actiniaria). Zoological Studies 47(1): 37-45. Aiptasia pulchella, an aquarium species and invasive pest, is used as a common model actinarian for laboratory-based experiments to study environmental regulation

  5. Exploiting the Nephrotoxic Effects of Venom from the Sea Anemone, Phyllodiscus semoni, to Create a Hemolytic Uremic Syndrome Model in the Rat

    PubMed Central

    Mizuno, Masashi; Ito, Yasuhiko; Morgan, B. Paul

    2012-01-01

    In the natural world, there are many creatures with venoms that have interesting and varied activities. Although the sea anemone, a member of the phylum Coelenterata, has venom that it uses to capture and immobilise small fishes and shrimp and for protection from predators, most sea anemones are harmless to man. However, a few species are highly toxic; some have venoms containing neurotoxins, recently suggested as potential immune-modulators for therapeutic application in immune diseases. Phyllodiscus semoni is a highly toxic sea anemone; the venom has multiple effects, including lethality, hemolysis and renal injuries. We previously reported that venom extracted from Phyllodiscus semoni induced acute glomerular endothelial injuries in rats resembling hemolytic uremic syndrome (HUS), accompanied with complement dysregulation in glomeruli and suggested that the model might be useful for analyses of pathology and development of therapeutic approaches in HUS. In this mini-review, we describe in detail the venom-induced acute renal injuries in rat and summarize how the venom of Phyllodiscus semoni could have potential as a tool for analyses of complement activation and therapeutic interventions in HUS. PMID:22851928

  6. Predicting suitable habitat for the gold coral Savalia savaglia (Bertoloni, 1819) (Cnidaria, Zoantharia) in the South Tyrrhenian Sea

    NASA Astrophysics Data System (ADS)

    Giusti, Michela; Innocenti, Carlo; Canese, Simonepietro

    2014-06-01

    The gold coral Savalia savaglia (Cnidaria, Zoantharia) is a rare component of the mesophotic zone of the Mediterranean Sea and northeastern Atlantic Ocean. During two field campaigns along the Italian coast in the South Tyrrhenian Sea, two populations of this species were discovered. The specimens were filmed and photographed by means of a Remotely Operated Vehicle (ROV). To identify the role of local bathymetry and other derived variables on presence and distribution of S. savaglia we used a Habitat Suitability (HS) modeling technique based on Ecological Niche Factor Analysis (ENFA), utilizing high-resolution multibeam bathymetry and ROV data. Among the set of environmental variables derived from multibeam data, slope, rugosity, eastness and distance to rocks, appear to be the main variables involved in S. savaglia distribution, pointing out that the habitat differs considerably from the mean environmental conditions over the study area, and that S. savaglia ecological niche is significantly narrower than the available habitat. The HS map was developed to differentiate the sea floor into suitability classes. The comparison between suitability classes and presence data showed that the HS map is coherent with the observed spatial distribution of the species. The most suitable habitat for S. savaglia is characterized by a rough sea floor with rocks that is steeply sloped, oriented northeast, and within a water depth range of 34-77 m. Our study suggests that predictive modeling is an approach that can be applied to other deep coral species to locate areas with a suitable habitat. Considering the difficulties to reach the habitats in which these species live, this approach could be essential to planning further studies that help define areas where the species may be present.

  7. The effect of sea anemone (H. magnifica) venom on two human breast cancer lines: death by apoptosis.

    PubMed

    Ramezanpour, Mahnaz; da Silva, Karen Burke; Sanderson, Barbara J S

    2014-10-01

    Venom from the sea anemone, Heteractis magnifica, has multiple biological effects including, cytotoxic, cytolytic and hemolytic activities. In this study, cytotoxicity induced by H. magnifica venom was investigated using the crystal violet assay on human breast cancer T47D and MCF7 cell lines and normal human breast 184B5 cell line. Apoptosis was also assayed via Annexin V-flourescein isothiocyanate and propidium iodide (PI) staining followed by flow cytometric analysis. Cell cycle progression and mitochondria membrane potential were studied via flow cytometry following PI and JC-1 staining respectively. H. magnifica venom induced significant reductions in viable cell numbers and increases in apoptosis in T47D and MCF7 in dose-dependent manners. A significant apoptosis-related increase in the sub G1 peak of the cell cycle in both breast cancer cell lines was also observed. Moreover, treatment by venom cleaved caspase-8, caspase-9, and activated caspase-3. Overall, H. magnifica venom was highly cytotoxic to T47D and MCF7 human breast cancer cells, and the phenomenon could be the killing phenomenon via the death receptor-mediated and the mitochondria-mediated apoptotic pathways. Consequently, H. magnifica venom has potential for the development of a breast cancer therapeutic. PMID:23989939

  8. In silico assessment of interaction of sea anemone toxin APETx2 and acid sensing ion channel 3.

    PubMed

    Rahman, Taufiq; Smith, Ewan St John

    2014-07-18

    Acid sensing ion channels (ASICs) are proton-gated cation channels that are expressed throughout the nervous system and have been implicated in mediating sensory perception of noxious stimuli. Amongst the six ASIC isoforms, ASIC1a, 1b, 2a and 3 form proton-gated homomers, which differ in their activation and inactivation kinetics, expression profiles and pharmacological modulation; protons do not gate ASIC2b and ASIC4. As with many other ion channels, structure-function studies of ASICs have been greatly aided by the discovery of some toxins that act in isoform-specific ways. ASIC3 is predominantly expressed by sensory neurons of the peripheral nervous system where it acts to detect acid as a noxious stimulus and thus plays an important role in nociception. ASIC3 is the only ASIC subunit that is inhibited by the sea anemone (Anthopleura elegantissima)-derived toxin APETx2. However, the molecular mechanism by which APETx2 interacts with ASIC3 remains largely unknown. In this study, we made a homology model of ASIC3 and used extensive protein-protein docking to predict for the first time, the probable sites of APETx2 interaction on ASIC3. Additionally, using computational alanine scanning, we also suggest the 'hot-spots' that are likely to be critical for ASIC3-APETx2 interaction. PMID:24942880

  9. Sequence-specific H NMR assignments and secondary structure in the sea anemone polypeptide Stichodactyla helianthus neurotoxin I

    SciTech Connect

    Fogh, R.H.; Mabbutt, B.C.; Kem, W.R.; Norton, R.S. (Univ. of New South Wales, Kensington (Australia))

    1989-02-21

    Sequence-specific assignments are reported for the 500-MHz H nuclear magnetic resonance (NMR) spectrum of the 48-residue polypeptide neurotoxin I from the sea anemone Stichodactyla helianthus (Sh I). Spin systems were first identified by using two-dimensional relayed or multiple quantum filtered correlation spectroscopy, double quantum spectroscopy, and spin lock experiments. Specific resonance assignments were then obtained from nuclear Overhauser enhancement (NOE) connectivities between protons from residues adjacent in the amino acid sequence. Of a total of 265 potentially observable resonances, 248 (i.e., 94%) were assigned, arising from 39 completely and 9 partially assigned amino acid spin systems. The secondary structure of Sh I was defined on the basis of the pattern of sequential NOE connectivities. NOEs between protons on separate strands of the polypeptide backbone, and backbone amide exchange rates. Sh I contains a four-stranded antiparallel {beta}-sheet encompassing residues 1-5, 16-24, 30-33, and 40-46, with a {beta}-bulge at residues 17 and 18 and a reverse turn, probably a type II {beta}-turn, involving residues 27-30. No evidence of {alpha}-helical structure was found.

  10. Embryonic and larval development of the host sea anemones Entacmaea quadricolor and Heteractis crispa.

    PubMed

    Scott, Anna; Harrison, Peter L

    2007-10-01

    Little information is available on the sexual reproductive biology of anemones that provide essential habitat for anemonefish. Here we provide the first information on the surface ultrastructural and morphological changes during development of the embryos and planula larvae of Entacmaea quadricolor and Heteractis crispa, using light and scanning electron microscopy. Newly spawned eggs of E. quadricolor and H. crispa averaged 794 microm and 589 microm diameter, respectively, and were covered by many spires of microvilli that were evenly distributed over the egg surface, except for a single bare patch. Eggs of both species contained abundant zooxanthellae when spawned, indicating vertical transmission of symbionts. Fertilization was external, and the resulting embryos displayed superficial cleavage. As development continued, individual blastomeres became readily distinguishable and a round-to-ovoid blastula was formed, which flattened with further divisions. The edges of the blastula thickened, creating a concave-convex dish-shaped gastrula. The outer margins of the gastrula appeared to roll inward, leading to the formation of an oral pore and a ciliated planula larva. Larval motility and directional movement were first observed 36 h after spawning. E. quadricolor larval survival remained high during the first 4 d after spawning, then decreased rapidly. PMID:17928518

  11. Optimization of preservation and processing of sea anemones for microbial community analysis using molecular tools.

    PubMed

    Rocha, Joana; Coelho, Francisco J R C; Peixe, Luísa; Gomes, Newton C M; Calado, Ricardo

    2014-01-01

    For several years, knowledge on the microbiome associated with marine invertebrates was impaired by the challenges associated with the characterization of bacterial communities. With the advent of culture independent molecular tools it is possible to gain new insights on the diversity and richness of microorganisms associated with marine invertebrates. In the present study, we evaluated if different preservation and processing methodologies (prior to DNA extraction) can affect the bacterial diversity retrieved from snakelocks anemone Anemonia viridis. Denaturing gradient gel electrophoresis (DGGE) community fingerprints were used as proxy to determine the bacterial diversity retrieved (H'). Statistical analyses indicated that preservation significantly affects H'. The best approach to preserve and process A. viridis biomass for bacterial community fingerprint analysis was flash freezing in liquid nitrogen (preservation) followed by the use of a mechanical homogenizer (process), as it consistently yielded higher H'. Alternatively, biomass samples can be processed fresh followed by cell lyses using a mechanical homogenizer or mortar &pestle. The suitability of employing these two alternative procedures was further reinforced by the quantification of the 16S rRNA gene; no significant differences were recorded when comparing these two approaches and the use of liquid nitrogen followed by processing with a mechanical homogenizer. PMID:25384534

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

    PubMed

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

    2013-01-01

    Augmentative biocontrol, defined as the use of indigenous natural enemies to control pest populations, has not been explored extensively in marine systems. This study tested the potential of the anemone Anthothoe albocincta as a biocontrol agent for biofouling on submerged artificial structures. Biofouling biomass was negatively related to anemone cover. Treatments with high anemone cover (>35%) led to significant changes in biofouling assemblages compared to controls. Taxa that contributed to these changes differed among sites, but included reductions in cover of problematic fouling organisms, such as solitary ascidians and bryozoans. In laboratory trials, A. albocincta substantially prevented the settlement of larvae of the bryozoan Bugula neritina when exposed to three levels of larval dose, suggesting predation as an important biocontrol mechanism, in addition to space pre-emption. This study demonstrated that augmentative biocontrol using anemones has the potential to reduce biofouling on marine artificial structures, although considerable further work is required to refine this tool before its application. PMID:23682610

  13. Differential accumulation of heavy metals in the sea anemone Anthopleura elegantissima as a function of symbiotic state

    E-print Network

    to either cadmium, copper, nickel or zinc chloride (0, 10, 100 mg l(1 for Cd, Cu and Ni; 0, 100, 1000 mg l(1 reserved. Keywords: Anemone; Cadmium; Copper; Nickel; Zinc; Cnidarian; Symbiosis * Corresponding author

  14. Ecological and developmental dynamics of a host-parasite system involving a sea anemone and two ctenophores.

    PubMed

    Reitzel, Adam M; Sullivan, James C; Brown, Briana K; Chin, Diana W; Cira, Emily K; Edquist, Sara K; Genco, Brandon M; Joseph, Oliver C; Kaufman, Christian A; Kovitvongsa, Kathryn; Muñoz, Martha M; Negri, Tiffany L; Taffel, Jonathan R; Zuehlke, Robert T; Finnerty, John R

    2007-12-01

    The lined sea anemone Edwardsiella lineata has evolved a derived parasitic life history that includes a novel body plan adapted for life inside its ctenophore hosts. Reputedly its sole host is the sea walnut, Mnemiopsis leidyi, a voracious planktivore and a seasonally abundant member of many pelagic ecosystems. However, we have observed substantially higher E. lineata prevalence in a second ctenophore species, the ctenophore predator Beroë ovata. The interplay among these 3 species has important conservation consequences as M. leidyi introductions are thought to be responsible for the severe depletion of numerous commercial fisheries in the Mediterranean basin, and both E. lineata and B. ovata have been proposed as biological controls for invasive M. leidyi. Over a 3-yr period (2004-2006), we collected 8,253 ctenophores from Woods Hole, Massachusetts, including M. leidyi, B. ovata, and a third ctenophore, Pleurobrachia pileus, and we recorded E. lineata infection frequencies, parasite load, and parasite location. We also conducted laboratory experiments to determine the likely mechanisms for parasite introduction and the effect of each host on parasite development. We observed peak E. lineata infection frequencies of 0% in P. pileus, 59% in M. leidyi, and 100% in B. ovata, suggesting that B. ovata could be an important natural host for E. lineata. However, in laboratory experiments, E. lineata larvae proved far more successful at infecting M. leidyi than B. ovata, and E. lineata parasites excised from M. leidyi exhibited greater developmental competence than parasites excised from B. ovata. Although we show that E. lineata is efficiently transferred from M. leidyi to B. ovata when the latter preys upon the former, we conclude that E. lineata larvae are not well adapted for parasitizing the latter species and that the E. lineata parasite is not well adapted for feeding in B. ovata; these developmental and ecological factors underlie the host specificity of this recently evolved parasite. PMID:18314686

  15. Autotrophy versus heterotrophy: The origin of carbon determines its fate in a symbiotic sea anemone

    Microsoft Academic Search

    Ami Bachar; Yair Achituv; Zohar Pasternak; Zvy Dubinsky

    2007-01-01

    Cnidarians – corals and their relatives – dominate the shallow, illuminated sea-floor in tropical nutrient-poor seas, mainly because their food sources are both heterotrophic, by predation, and autotrophic, from their intracellular symbiotic microalgae, the zooxanthellae. This trophic flexibility is rare in the animal kingdom, and the cellular usage and biological lifetime of the organic food molecules derived from both sources

  16. Nme Gene Family Evolutionary History Reveals Pre-Metazoan Origins and High Conservation between Humans and the Sea Anemone, Nematostella vectensis

    PubMed Central

    Desvignes, Thomas; Pontarotti, Pierre; Bobe, Julien

    2010-01-01

    Background The Nme gene family is involved in multiple physiological and pathological processes such as cellular differentiation, development, metastatic dissemination, and cilia functions. Despite the known importance of Nme genes and their use as clinical markers of tumor aggressiveness, the associated cellular mechanisms remain poorly understood. Over the last 20 years, several non-vertebrate model species have been used to investigate Nme functions. However, the evolutionary history of the family remains poorly understood outside the vertebrate lineage. The aim of the study was thus to elucidate the evolutionary history of the Nme gene family in Metazoans. Methodology/Principal Findings Using a total of 21 eukaryote species including 14 metazoans, the evolutionary history of Nme genes was reconstructed in the metazoan lineage. We demonstrated that the complexity of the Nme gene family, initially thought to be restricted to chordates, was also shared by the metazoan ancestor. We also provide evidence suggesting that the complexity of the family is mainly a eukaryotic innovation, with the exception of Nme8 that is likely to be a choanoflagellate/metazoan innovation. Highly conserved gene structure, genomic linkage, and protein domains were identified among metazoans, some features being also conserved in eukaryotes. When considering the entire Nme family, the starlet sea anemone is the studied metazoan species exhibiting the most conserved gene and protein sequence features with humans. In addition, we were able to show that most of the proteins known to interact with human NME proteins were also found in starlet sea anemone. Conclusion/Significance Together, our observations further support the association of Nme genes with key cellular functions that have been conserved throughout metazoan evolution. Future investigations of evolutionarily conserved Nme gene functions using the starlet sea anemone could shed new light on a wide variety of key developmental and cellular processes. PMID:21085602

  17. Spatial gene expression quantification: a tool for analysis of in situ hybridizations in sea anemone Nematostella vectensis

    PubMed Central

    2012-01-01

    Background Spatial gene expression quantification is required for modeling gene regulation in developing organisms. The fruit fly Drosophila melanogaster is the model system most widely applied for spatial gene expression analysis due to its unique embryonic properties: the shape does not change significantly during its early cleavage cycles and most genes are differentially expressed along a straight axis. This system of development is quite exceptional in the animal kingdom. In the sea anemone Nematostella vectensis the embryo changes its shape during early development; there are cell divisions and cell movement, like in most other metazoans. Nematostella is an attractive case study for spatial gene expression since its transparent body wall makes it accessible to various imaging techniques. Findings Our new quantification method produces standardized gene expression profiles from raw or annotated Nematostella in situ hybridizations by measuring the expression intensity along its cell layer. The procedure is based on digital morphologies derived from high-resolution fluorescence pictures. Additionally, complete descriptions of nonsymmetric expression patterns have been constructed by transforming the gene expression images into a three-dimensional representation. Conclusions We created a standard format for gene expression data, which enables quantitative analysis of in situ hybridizations from embryos with various shapes in different developmental stages. The obtained expression profiles are suitable as input for optimization of gene regulatory network models, and for correlation analysis of genes from dissimilar Nematostella morphologies. This approach is potentially applicable to many other metazoan model organisms and may also be suitable for processing data from three-dimensional imaging techniques. PMID:23039089

  18. Neptunomonas phycophila sp. nov. isolated from a culture of Symbiodinium sp., a dinoflagellate symbiont of the sea anemone Aiptasia tagetes.

    PubMed

    Frommlet, Jörg; Guimarães, Bárbara; Sousa, Lígia; Serôdio, João; Alves, Artur

    2015-03-01

    A Gram-stain-negative, facultatively anaerobic, oxidase- and catalase-positive, rod-shaped bacterium, strain SYM1(T), was isolated from a culture of Symbiodinium sp., an algal symbiont of the sea anemone Aiptasia tagetes collected in Puerto Rico. Growth was observed at 4-40 °C (optimum 30 °C), at pH 5.0-11.0 (optimum pH 8.0) and with 0.5-8?% (optimum 2?%) (w/v) NaCl. Phylogenetic analyses of 16S rRNA gene sequences showed that strain SYM1(T) was a member of the genus Neptunomonas with the type strain of Neptunomonas naphthovorans as the closest phylogenetic relative with a pairwise sequence similarity of 98.15?%. However, DNA-DNA relatedness between strain SYM1(T) and N. naphthovorans CIP 106451(T) was 24?%. Moreover, strain SYM1(T) could be distinguished from its closest relative by several phenotypic characteristics such as NaCl, pH and temperature tolerance, nitrate reduction and utilization of carbon substrates. The major cellular fatty acids were C16?:?0, C18?:?1?7c and summed feature 3 (comprising C16?:?1?7c and/or iso-C15?:?0 2-OH). The genomic DNA G+C content of strain SYM1(T) was 45 mol%. Ubiquinone-8 (Q-8) was the only respiratory quinone detected. Based on a polyphasic taxonomic characterization, strain SYM1(T) represents a novel species of the genus Neptunomonas, for which the name Neptunomonas phycophila sp. nov. is proposed. The type strain is SYM1(T) (?=?LMG 28329(T)?=?CECT 8716(T)). PMID:25563909

  19. Employing BAC-reporter constructs in the sea anemone Nematostella vectensis.

    PubMed

    Fischer, Antje H L; Tulin, Sarah; Fredman, David; Smith, Joel

    2013-11-01

    Changes in the expression and function of genes drive evolutionary change. Comparing how genes are regulated in different species is therefore becoming an important part of evo-devo studies. A key tool for investigating the regulation of genes is represented by bacterial artificial chromosomes (BAC)-reporter constructs. BACs are large insert libraries, often >100 kb, which thus capture the genomic sequences surrounding a gene of interest, including all, or nearly all, of the elements underpinning regulation. Recombinant BACs, containing a reporter gene in place of the endogenous coding sequence of genes, can be utilized to drive the expression of reporter genes under the regulatory control of the gene of interest while still embedded within its genomic context. Systematic deletions within the BAC-reporter construct can be used to identify the minimal reporter in an unbiased way, avoiding the risk of overlooking regulatory elements that may be many kilobases away from the transcription start-site. Nematostella vectensis (Edwardsiidae, Anthozoa, Cnidaria) has become an important model in regenerative biology, ecology, and especially in studies of evo-devo and gene-regulatory networks due to its interesting phylogenetic position and amenability to molecular techniques. The increasing interest in this rising model system also led to a demand for methods that can be used to study the regulation of genes in Nematostella. Here, we present our progress in employing BAC-reporter constructs to visualize gene-expression in Nematostella. Using a new Nematostella-specific recombination cassette, we made nine different BAC-reporter constructs. Although five BAC recombinants gave variable effects, three constructs, namely Nv-bra:eGFP::L10 BAC, Nv-dpp:eGFP::L10 BAC, and Nv-grm:eGFP::L10 BAC delivered promising results. We show that these three constructs express the reporter gene eGFP in 10.4-17.2% of all analyzed larvae, out of which 26.2-41.9% express GFP in a mosaic fashion within the expected domain. In addition to the expression within the known domains, we also observed cases of misexpression of eGFP and examples that could represent actual expression outside the described domain. Furthermore, we deep-sequenced and assembled five different BACs containing Nv-chordin, Nv-foxa, Nv-dpp, Nv-wnta, and Nv-wnt1, to improve assembly around these genes. The use of BAC-reporter constructs will foster cis-regulatory analyses in Nematostella and thus help to improve our understanding of the regulatory network in this cnidarian system. Ultimately, this will advance the comparison of gene-regulation across species and lead to a much better understanding of evolutionary changes and novelties. PMID:23956207

  20. Purification and inflammatory edema induced by two PLA2 (Anch TX-I and Anch TX-II) from sea anemone Anthothoe chilensis (Actiniaria: Sagartiidae).

    PubMed

    Landucci, Elen Cristina Teizem; Dias, Queila Cristina; Marangoni, Fábio André; Vilca-Quispe, Augusto; Valeriano-Zapana, José Antonio; Torres-Huaco, Frank Denis; Martins-de-Souza, Daniel; Marangoni, Sergio; Ponce-Soto, Luis Alberto

    2012-02-01

    The Anch TX-I and II PLA(2) were purified from Anthothoe chilensis (Lesson, 1830) from the extract of the anemone after only two chromatographic step using molecular exclusion chromatography (Sephadex G-75) and reverse phase HPLC on ?-Bondapak C18 column. Both PLA(2) showed a molecular mass of ~14kDa determined by MALDI-TOF mass spectrometry and showed a high catalytic activity (data not showed). Although homologous with mammalian or snake venom group I PLA(2)s, Anch TX-I and II is sufficiently structurally different for the question of its placement into the existing PLA(2) classification scheme to arise. In addition, Anch TX-I and II, despite possessing many common structural features, also differ in some important structural properties. The amino acid sequence of both PLA(2) (Anch TX-I and III) showed high amino acid sequence identity with PLA(2)Rhopilema nomadica and Bunodosoma caissarum Cnidaria and PLA(2) of group III protein isolated from the Mexican lizard Heloderma horridum horridum and Heloderma suspectum. In addition, Anch TX-I and Anch TX-II showed high amino acid sequence identity with PLA(2) from group III also showed significant overall homology to bee Apis dorsata, Bombus terrestris and Bombus pennsylvanicus and PLA(2). We also investigated the in vivo edematogenic activity of Anch TX-I and Anch TX-II in a model of paw and skin edema in rats and observed that both are able to induce dose-dependent edema. PMID:22100907

  1. Early evolution of a homeobox gene: the parahox gene Gsx in the Cnidaria and the Bilateria.

    PubMed

    Finnerty, John R; Paulson, David; Burton, Pat; Pang, Kevin; Martindale, Mark Q

    2003-01-01

    Homeobox transcription factors are commonly involved in developmental regulation in diverse eukaryotes, including plants, animals, and fungi. The origin of novel homeobox genes is thought to have contributed to many evolutionary innovations in animals. We perform a molecular phylogenetic analysis of cnox2, the best studied homeobox gene from the phylum Cnidaria, a very ancient lineage of animals. Among three competing hypotheses, our analysis decisively favors the hypothesis that cnox2 is orthologous to the gsx gene of Bilateria, thereby establishing the existence of this specific homeobox gene in the eumetazoan stem lineage, some 650-900 million years ago. We assayed the expression of gsx in the planula larva and polyp of the sea anemone Nematostella vectensis using in situ hybridization and reverse transcriptase polymerase chain reaction. The gsx ortholog of Nematostella, known as anthox2, is expressed at high levels in the posterior planula and the corresponding "head" region of the polyp. It cannot be detected in the anterior planula or the corresponding "foot" region of the polyp. We have attempted to reconstruct the evolution of gsx spatiotemporal expression in cnidarians and bilaterians using a phylogenetic framework. Because of the surprisingly high degree of variability in gsx expression within the Cnidaria, it is currently not possible to infer unambiguously the ancestral cnidarian condition or the ancestral eumetazoan condition for gsx expression. PMID:12823450

  2. The Evolution of MicroRNA Pathway Protein Components in Cnidaria

    PubMed Central

    Moran, Yehu; Praher, Daniela; Fredman, David; Technau, Ulrich

    2013-01-01

    In the last decade, it became evident that posttranscriptional regulation of gene expression by microRNAs is a central biological process in both plants and animals. Yet, our knowledge about microRNA biogenesis and utilization in animals stems mostly from the study of Bilateria. In this study, we identified genes encoding the protein components of different parts of the microRNA pathway in Cnidaria, the likely sister phylum of Bilateria. These genes originated from three cnidarian lineages (sea anemones, stony corals, and hydras) that are separated by at least 500 My from one another. We studied the expression and phylogeny of the cnidarian homologs of Drosha and Pasha (DGCR8) that compose the microprocessor, the RNAse III enzyme Dicer and its partners, the HEN1 methyltransferase, the Argonaute protein effectors, as well as members of the GW182 protein family. We further reveal that whereas the bilaterian dicer partners Loquacious/TRBP and PACT are absent from Cnidaria, this phylum contains homologs of the double-stranded RNA-binding protein HYL1, the Dicer partner found in plants. We also identified HYL1 homologs in a sponge and a ctenophore. This finding raises questions regarding the independent evolution of the microRNA pathway in plants and animals, and together with the other results shed new light on the evolution of an important regulatory pathway. PMID:24030553

  3. Development of Highly Selective Kv1.3-Blocking Peptides Based on the Sea Anemone Peptide ShK

    PubMed Central

    Pennington, Michael W.; Chang, Shih Chieh; Chauhan, Satendra; Huq, Redwan; Tajhya, Rajeev B.; Chhabra, Sandeep; Norton, Raymond S.; Beeton, Christine

    2015-01-01

    ShK, from the sea anemone Stichodactyla helianthus, is a 35-residue disulfide-rich peptide that blocks the voltage-gated potassium channel Kv1.3 at ca. 10 pM and the related channel Kv1.1 at ca. 16 pM. We developed an analog of this peptide, ShK-186, which is currently in Phase 1b-2a clinical trials for the treatment of autoimmune diseases such as multiple sclerosis and rheumatoid arthritis. While ShK-186 displays a >100-fold improvement in selectivity for Kv1.3 over Kv1.1 compared with ShK, there is considerable interest in developing peptides with an even greater selectivity ratio. In this report, we describe several variants of ShK that incorporate p-phophono-phenylalanine at the N-terminus coupled with internal substitutions at Gln16 and Met21. In addition, we also explored the combinatorial effects of these internal substitutions with an alanine extension at the C-terminus. Their selectivity was determined by patch-clamp electrophysiology on Kv1.3 and Kv1.1 channels stably expressed in mouse fibroblasts. The peptides with an alanine extension blocked Kv1.3 at low pM concentrations and exhibited up to 2250-fold selectivity for Kv1.3 over Kv1.1. Analogs that incorporates p-phosphono-phenylalanine at the N-terminus blocked Kv1.3 with IC50s in the low pM range and did not affect Kv1.1 at concentrations up to 100 nM, displaying a selectivity enhancement of >10,000-fold for Kv1.3 over Kv1.1. Other potentially important Kv channels such as Kv1.4 and Kv1.6 were only partially blocked at 100 nM concentrations of each of the ShK analogs. PMID:25603346

  4. The partial purification and bioassay of a toxin present in extracts of the sea anemone, Tealia felina (L.).

    PubMed Central

    Aldeen, S. I.; Elliott, R. C.; Sheardown, M.

    1981-01-01

    1. Column chromatography with Agarose A50m followed by Sephadex G100 was used to separate a fraction (extract II) in the molecular weight range 12,000 to 14,000 daltons from saline extracts of the sea anemone, Tealia felina. 2. Extract II inhibited histamine-induced contractions of the guinea-pig ileum and produced haemolysis of human blood, effects on which bioassays were based. 3. The potency of extracts was assayed. A standard unit of activity (= AU) was defined such that 100 AU produced 90% inhibition of histamine-induced contractions of the guinea-pig ileum after 30 to 35 min exposure. 4. The relationship between activity of the extracts measured on the ileum and their haemolytic activity was studied, providing a second assay method based on the latter property. 5 Based on values from both methods of assay, the calculated yield in AU at the end of the separation procedure was 0.53 AU for each AU present in the original extract. In crude extract there were 5.0 AU/mg dry weight and 36.7 AU/mg protein, and after separation (extract II) there were 11.2 AU/mg dry weight and 312.2 AU/mg protein. 6 The acute LD50 values determined in mice (i.v.) were: for crude extract 124 mg/kg for extract I, 76 mg/kg and for extract II, 69 mg/kg. 7 Extract II (0.18 to 0.72 AU/ml) produced a slowly developing contraction of guinea-pig ileum. Indomethacin (2.8 x 10(-5) M) substantially reduced this response. 8 Extract II (0.03 AU/ml) reduced the contractile response of the guinea-pig ileum to acetylcholine by 39 +/- 8%, n = 6, and the response to histamine by 26 +/- 6.6%, n = 6. The response to 5-hydroxytryptamine (5-HT) was not reduced by 0.08 AU/ml of extract II, a concentration that actually increased the contractile response to KC1 by 32 +/- 11.2% n = 7. 9 It is proposed that for future work on the extract a new AU should be used. This AU is defined such that 50 AU produce 50% inhibition of histamine-induced contractions of the guinea-pig ileum after 30 to 35 min exposure. PMID:6111370

  5. Population dynamics of Eudendrium glomeratum (Cnidaria: Anthomedusae) on the Portofino Promontory (Ligurian Sea)

    Microsoft Academic Search

    F. Boero; A. Balduzzi; G. Bavestrello; B. Caffa; R. Cattaneo Vietti

    1986-01-01

    Eudendrium glomeratum Picard, in the Ligurian Sea, is one of the major components of hard-bottom sessile zoobenthos in the cold season. It settles mainly between 10 and 40 m depth, forming a seasonal facies. The presence of E. glomeratum has been evaluated by measuring in situ the height of the colonies present within a standard surface of 1 m2. Observations

  6. Hydralysins, a New Category of -Pore-forming Toxins in Cnidaria*S

    E-print Network

    Lebendiker, Mario

    of action. Cnidarians (corals, sea anemones, jellyfish, and hydrae) are an evolutionarily ancient group in the life threatening stings of the Portuguese Man- O-War (Physalia physalis) and of box jellyfish (4

  7. Reproduction of the colonial hydroid Obelia geniculata (L., 1758) (Cnidaria, Hydrozoa) in the White Sea

    Microsoft Academic Search

    Sergei A. Slobodov; Nickolai N. Marfenin

    Populations of the colonial hydroid Obelia geniculata in the White Sea reproduce asexually by frustule formation. Young medusae appear in the plankton during July and August.\\u000a The number of medusae rarely exceeds 36 per m3, and the average number varies every year from 0.4 to 10 per m3. The size of medusae is smaller than reported from other regions. The

  8. Structure-function relationships of the major neurotoxin from the sea anemone Stichodactyla helianthus with a new sodium channel receptor site

    SciTech Connect

    Pennington, M.W.

    1988-01-01

    We have determined that ShN I, a 48-residue type 2 sea anemone toxin, delays the inactivation of the Na channel in lobster olfactory somas. The receptor for ShN I was identified in vesicle preparations of neuronal tissues from both crustaceans and mammals; however, the K{sub D} values for the former is more than 1,000 fold lower for the later. The binding of ({sup 125}I)-ShN I to this receptor was determined to be unaffected by Anemonia sulcata II, depolarization of the membrane, or veratridine. ShN I was unable to displace ({sup 125}I)-Androctonus austrialis Hector II, whereas unlabeled AaH II and As II displaced the labeled scorpion toxin from rat brain synaptosomes. This is the first characterization of a new Na channel receptor site which specifically binds type 2 anemone toxins. To study the interactions that specific amino acid residues of ShN I have with this receptor, we developed a strategy using solid phase peptide synthesis. Prior to the synthesis of analogs to ShN I, we assembled the native ShN I sequence and reoxidized the three intramolecular disulfide bonds. Chemical, physical, and pharmacological characterization of the purified synthetic ShN I showed it to be indistinguishable from the natural toxin.

  9. Assemblage and interaction structure of the anemonefish-anemone mutualism across the Manado

    E-print Network

    Northampton, University of

    Assemblage and interaction structure of the anemonefish-anemone mutualism across the Manado region of anemonefish and sea anemones--allows us to test different hypotheses focused on the obligate mutualism between specialist. Keywords Coral reef fish . Anemone . Symbiosis . Mutualism . Interaction structure . Nestedness

  10. Evidence for involvement of TRPA1 in the detection of vibrations by hair bundle mechanoreceptors in sea anemones

    Microsoft Academic Search

    Janna L. Mahoney; Erin M. Graugnard; Patricia Mire; Glen M. Watson

    2011-01-01

    A homolog of TRPA1 was identified in the genome of the anemone, Nematostella vectensis (nv-TRPA1a), and predicted to possess six ankyrin repeat domains at the N-terminus and an ion channel domain near the C-terminus.\\u000a Transmembrane segments of the ion channel domain are well conserved among several known TRPA1 polypeptides. Inhibitors of\\u000a TRPA1 including ruthenium red decrease vibration-dependent discharge of nematocysts

  11. Multiple components in ink of the sea hare Aplysia californica are aversive to the sea anemone Anthopleura sola

    Microsoft Academic Search

    Cynthia E. Kicklighter; Charles D. Derby

    2006-01-01

    Sea hares of the genus Aplysia rely on an array of behavioral and chemical defenses, including the release of ink and opaline, to protect themselves from predation. While many studies have demonstrated that ink and opaline are repellent to predators, very little is known about which components of these secretions are active against predators. Ink was previously shown to facilitate

  12. Detrimental effects of host anemone bleaching on anemonefish populations

    Microsoft Academic Search

    P. Saenz-Agudelo; G. P. Jones; S. R. Thorrold; S. Planes

    2011-01-01

    Coral bleaching and related reef degradation have caused significant declines in the abundance of reef-associated fishes. Most attention on the effects of bleaching has focused on corals, but bleaching is also prevalent in other cnidarians, including sea anemones. The consequences of anemone bleaching are unknown, and the demographic effects of bleaching on associated fish recruitment, survival, and reproduction are poorly

  13. Accepted by M. Daly: 10 Apr. 2012; published: 4 Jul. 2012 ISSN 1175-5326 (print edition)

    E-print Network

    Fautin, Daphne

    .mapress.com/zootaxa/ Monograph ZOOTAXA Taxonomy and distribution of sea anemones (Cnidaria: Actiniaria and Corallimorpharia) from-LOUCKS& DAPHNE G. FAUTIN Taxonomy and distribution of sea anemones (Cnidaria: Actiniaria and Corallimorpharia

  14. Increasing pCO2 correlates with low concentrations of intracellular dimethylsulfoniopropionate in the sea anemone Anemonia viridis.

    PubMed

    Borell, Esther M; Steinke, Michael; Horwitz, Rael; Fine, Maoz

    2014-02-01

    Marine anthozoans maintain a mutualistic symbiosis with dinoflagellates that are prolific producers of the algal secondary metabolite dimethylsulfoniopropionate (DMSP), the precursor of the climate-cooling trace gas dimethyl sulfide (DMS). Surprisingly, little is known about the physiological role of DMSP in anthozoans and the environmental factors that regulate its production. Here, we assessed the potential functional role of DMSP as an antioxidant and determined how future increases in seawater pCO2 may affect DMSP concentrations in the anemone Anemonia viridis along a natural pCO2 gradient at the island of Vulcano, Italy. There was no significant difference in zooxanthellae genotype and characteristics (density of zooxanthellae, and chlorophyll a) as well as protein concentrations between anemones from three stations along the gradient, V1 (3232 ?atm CO2), V2 (682 ?atm) and control (463 ?atm), which indicated that A.?viridis can acclimate to various seawater pCO2. In contrast, DMSP concentrations in anemones from stations V1 (33.23?±?8.30 fmol cell(-1)) and V2 (34.78?±?8.69 fmol cell(-1)) were about 35% lower than concentrations in tentacles from the control station (51.85?±?12.96 fmol cell(-1)). Furthermore, low tissue concentrations of DMSP coincided with low activities of the antioxidant enzyme superoxide dismutase (SOD). Superoxide dismutase activity for both host (7.84?±?1.37?U·mg(-1) protein) and zooxanthellae (2.84?±?0.41?U·mg(-1) protein) at V1 was 40% lower than at the control station (host: 13.19?±?1.42; zooxanthellae: 4.72?±?0.57?U·mg(-1) protein). Our results provide insight into coastal DMSP production under predicted environmental change and support the function of DMSP as an antioxidant in symbiotic anthozoans. PMID:24634728

  15. Increasing pCO2 correlates with low concentrations of intracellular dimethylsulfoniopropionate in the sea anemone Anemonia viridis

    PubMed Central

    Borell, Esther M; Steinke, Michael; Horwitz, Rael; Fine, Maoz

    2014-01-01

    Marine anthozoans maintain a mutualistic symbiosis with dinoflagellates that are prolific producers of the algal secondary metabolite dimethylsulfoniopropionate (DMSP), the precursor of the climate-cooling trace gas dimethyl sulfide (DMS). Surprisingly, little is known about the physiological role of DMSP in anthozoans and the environmental factors that regulate its production. Here, we assessed the potential functional role of DMSP as an antioxidant and determined how future increases in seawater pCO2 may affect DMSP concentrations in the anemone Anemonia viridis along a natural pCO2 gradient at the island of Vulcano, Italy. There was no significant difference in zooxanthellae genotype and characteristics (density of zooxanthellae, and chlorophyll a) as well as protein concentrations between anemones from three stations along the gradient, V1 (3232 ?atm CO2), V2 (682 ?atm) and control (463 ?atm), which indicated that A.?viridis can acclimate to various seawater pCO2. In contrast, DMSP concentrations in anemones from stations V1 (33.23?±?8.30 fmol cell?1) and V2 (34.78?±?8.69 fmol cell?1) were about 35% lower than concentrations in tentacles from the control station (51.85?±?12.96 fmol cell?1). Furthermore, low tissue concentrations of DMSP coincided with low activities of the antioxidant enzyme superoxide dismutase (SOD). Superoxide dismutase activity for both host (7.84?±?1.37?U·mg?1 protein) and zooxanthellae (2.84?±?0.41?U·mg?1 protein) at V1 was 40% lower than at the control station (host: 13.19?±?1.42; zooxanthellae: 4.72?±?0.57?U·mg?1 protein). Our results provide insight into coastal DMSP production under predicted environmental change and support the function of DMSP as an antioxidant in symbiotic anthozoans. PMID:24634728

  16. Determination of the three-dimensional solution structure of the antihypertensive and antiviral protein BDS-I from the sea anemone Anemonia sulcata: A study using nuclear magnetic resonance and hybrid distance geometry-dynamical simulated annealing

    Microsoft Academic Search

    Paul C. Driscoll; Angela M. Gronenborn; Laszlo Beress; G. Marius Clore

    1989-01-01

    The three-dimensional solution structure of the antihypertensive and antiviral protein BDS-I from the sea anemone Anemonia sulcata has been determined on the basis of 489 interproton and 24 hydrogen-bonding distance restraints supplemented by 23 Ï backbone and 21 {sub Ï1} side-chain torsion angle restraints derived from nuclear magnetic resonance (NMR) measurements. A total of 42 structures is calculated by a

  17. Nervous systems of the sea anemone Nematostella vectensis are generated by ectoderm and endoderm and shaped by distinct mechanisms.

    PubMed

    Nakanishi, Nagayasu; Renfer, Eduard; Technau, Ulrich; Rentzsch, Fabian

    2012-01-01

    As a sister group to Bilateria, Cnidaria is important for understanding early nervous system evolution. Here we examine neural development in the anthozoan cnidarian Nematostella vectensis in order to better understand whether similar developmental mechanisms are utilized to establish the strikingly different overall organization of bilaterian and cnidarian nervous systems. We generated a neuron-specific transgenic NvElav1 reporter line of N. vectensis and used it in combination with immunohistochemistry against neuropeptides, in situ hybridization and confocal microscopy to analyze nervous system formation in this cnidarian model organism in detail. We show that the development of neurons commences in the ectoderm during gastrulation and involves interkinetic nuclear migration. Transplantation experiments reveal that sensory and ganglion cells are autonomously generated by the ectoderm. In contrast to bilaterians, neurons are also generated throughout the endoderm during planula stages. Morpholino-mediated gene knockdown shows that the development of a subset of ectodermal neurons requires NvElav1, the ortholog to bilaterian neural elav1 genes. The orientation of ectodermal neurites changes during planula development from longitudinal (in early-born neurons) to transverse (in late-born neurons), whereas endodermal neurites can grow in both orientations at any stage. Our findings imply that elav1-dependent ectodermal neurogenesis evolved prior to the divergence of Cnidaria and Bilateria. Moreover, they suggest that, in contrast to bilaterians, almost the entire ectoderm and endoderm of the body column of Nematostella planulae have neurogenic potential and that the establishment of connectivity in its seemingly simple nervous system involves multiple neurite guidance systems. PMID:22159579

  18. Prolonged exposure to elevated CO2 promotes growth of the algal symbiont Symbiodinium muscatinei in the intertidal sea anemone Anthopleura elegantissima

    PubMed Central

    Towanda, Trisha; Thuesen, Erik V.

    2012-01-01

    Summary Some photosynthetic organisms benefit from elevated levels of carbon dioxide, but studies on the effects of elevated PCO2 on the algal symbionts of animals are very few. This study investigated the impact of hypercapnia on a photosynthetic symbiosis between the anemone Anthopleura elegantissima and its zooxanthella Symbiodinium muscatinei. Anemones were maintained in the laboratory for 1 week at 37?Pa PCO2 and pH?8.1. Clonal pairs were then divided into two groups and maintained for 6 weeks under conditions naturally experienced in their intertidal environment, 45?Pa PCO2, pH?8.1 and 231?Pa PCO2, pH?7.3. Respiration and photosynthesis were measured after the 1-week acclimation period and after 6 weeks in experimental conditions. Density of zooxanthellal cells, zooxanthellal cell size, mitotic index and chlorophyll content were compared between non-clonemate anemones after the 1-week acclimation period and clonal anemones at the end of the experiment. Anemones thrived in hypercapnia. After 6 weeks, A. elegantissima exhibited higher rates of photosynthesis at 45?Pa (4.2?µmol O2 g?1 h?1) and 231?Pa (3.30?µmol O2 g?1 h?1) than at the initial 37?Pa (1.53?µmol O2 g?1 h?1). Likewise, anemones at 231?Pa received more of their respiratory carbon from zooxanthellae (CZAR ?=?78.2%) than those at 37?Pa (CZAR ?=?66.6%) but less than anemones at 45?Pa (CZAR ?=?137.3%). The mitotic index of zooxanthellae was significantly greater in the hypercapnic anemones than in anemones at lower PCO2. Excess zooxanthellae were expelled by their hosts, and cell densities, cell diameters and chlorophyll contents were not significantly different between the groups. The response of A. elegantissima to hypercapnic acidification reveals the potential adaptation of an intertidal, photosynthetic symbiosis for high PCO2. PMID:23213455

  19. Is boldness a resource-holding potential trait? Fighting prowess and changes in startle response in the sea anemone, Actinia equina

    PubMed Central

    Rudin, Fabian S.; Briffa, Mark

    2012-01-01

    Contest theory predicts the evolution of a stable mixture of different strategies for fighting. Here, we investigate the possibility that stable between-individual differences in startle-response durations influence fighting ability or ‘resource-holding potential’ (RHP) in the beadlet sea anemone, Actinia equina. Both winners and losers showed significant repeatability of pre-fight startle-response durations but mean pre-fight startle-response durations were greater for eventual losers than for eventual winners, indicating that RHP varies with boldness. In particular, individuals with short startle responses inflicted more attacks on their opponent. Both repeatability and mean-level responses were changed by the experience of fighting, and these changes varied with outcome. In losers, repeatability was disrupted to a greater extent and the mean startle-response durations were subject to a greater increase than in winners. Thus, following a fight, this behavioural correlate of RHP behaves in a way similar to post-fight changes in physiological status, which can also vary between winners and losers. Understanding the links between aggression and boldness therefore has the potential to enhance our understanding of both the evolution of animal personality and the ‘winner and loser effects’ of post-fight changes in RHP. PMID:22171080

  20. Two-dimensional crystallization on lipid monolayers and three-dimensional structure of sticholysin II, a cytolysin from the sea anemone Stichodactyla helianthus.

    PubMed Central

    Martín-Benito, J; Gavilanes, F; de Los Ríos, V; Mancheño, J M; Fernández, J J; Gavilanes, J G

    2000-01-01

    Sticholysin II (Stn II), a potent cytolytic protein isolated from the sea anemone Stichodactyla helianthus, has been crystallized on lipid monolayers. With Fourier-based methods, a three-dimensional (3D) model of Stn II, up to a resolution of 15 A, has been determined. The two-sided plane group is p22(1)2, with dimensions a = 98 A, b = 196 A. The 3D model of Stn II displays a Y-shaped structure, slightly flattened, with a small curvature along its longest dimension (51 A). This protein, with a molecular mass of 19. 2 kDa, is one of the smallest structures reconstructed with this methodology. Two-dimensional (2D) crystals of Stn II on phosphatidylcholine monolayers present a unit cell with two tetrameric motifs, with the monomers in two different orientations: one with its longest dimension lying on the crystal plane and the other with this same axis leaning at an angle of approximately 60 degrees with the crystal plane. PMID:10827995

  1. Nitric oxide mediates coral bleaching through an apoptotic-like cell death pathway: evidence from a model sea anemone-dinoflagellate symbiosis.

    PubMed

    Hawkins, Thomas D; Bradley, Benjamin J; Davy, Simon K

    2013-12-01

    Coral bleaching (involving the loss of symbiotic algae from the cnidarian host) is a major threat to coral reefs and appears to be mediated at the cellular level by nitric oxide (NO). In this study, we examined the specific role of NO in bleaching using the sea anemone Aiptasia pulchella, a model system for the study of corals. Exposure of A. pulchella to high-temperature shock (26-33°C over <1 h) or an NO donor (S-nitrosoglutathione) resulted in significant increases in host caspase-like enzyme activity. These responses were reflected in the intensities of bleaching, which were significantly higher in heat- or NO-treated specimens than in controls maintained in seawater at 26°C. Notably, the inhibition of caspase-like activity prevented bleaching even in the presence of an NO donor or at elevated temperature. The additional use of an NO scavenger controlled for effects mediated by agents other than NO. We also exposed A. pulchella to a more ecologically relevant treatment (an increase from 26 to 33°C over 6-7 d). Again, host NO synthesis correlated with the activation of caspase-like enzyme activity. Therefore, we conclude that NO's involvement in cnidarian bleaching arises through the regulation of host apoptotic pathways. PMID:23934282

  2. Improved purification and enzymatic properties of a mixture of Sticholysin I and II: isotoxins with hemolytic and phospholipase A(2) activities from the sea anemone Stichodactyla helianthus.

    PubMed

    del Monte-Martínez, Alberto; González-Bacerio, Jorge; Romero, Lázara; Aragón, Carlos; Martínez, Diana; de Los Á Chávez, María; Álvarez, Carlos; Lanio, María E; Guisán, José M; Díaz, Joaquín

    2014-03-01

    Sticholysin I and Sticholysin II (StI and StII) are two potent hemolysins which form pores in natural and model membranes at nanomolar concentrations. These proteins were purified from the aqueous extract of the sea anemone Stichodactyla helianthus, Ellis 1768, by gel filtration and ionic exchange chromatography. This procedure rendered StI and StII with high purity (purification factors: 36 and 50, respectively) but a low yield of hemolytic activity, HA (<3%). Additionally, these toxins exhibited very low phospholipase activity (10(-3)U/mg of protein). In this work, a mixture StI-StII was obtained (yield >95%, with an increase in specific activity: 14 times) from the animal extract using an oxidized phospholipid-based affinity chromatographic matrix binding phospholipases. Cytolysin identification in the mixture was performed by immunoblotting and N-terminal sequence analyses. Phospholipase A2 (PLA2) activity of StI-StII was relatively high (1.85U/mg) and dependent of Ca(2+). The activity resulted optimum when was measured with the mostly unsaturated soybean phosphatidylcholine (PC), when compared to the less unsaturated egg PC or completely saturated dipalmitoyl PC, in the presence of 40mM Ca(2+) at pH 8.0. This Ca(2+) concentration did not exert any effect on binding of StI-StII with soybean PC monolayers. Then, PLA2 activity seems not be required to binding to membranes. PMID:24326193

  3. The p53 Tumor Suppressor-Like Protein nvp63 Mediates Selective Germ Cell Death in the Sea Anemone Nematostella vectensis

    PubMed Central

    Pankow, Sandra; Bamberger, Casimir

    2007-01-01

    Here we report the identification and molecular function of the p53 tumor suppressor-like protein nvp63 in a non-bilaterian animal, the starlet sea anemone Nematostella vectensis. So far, p53-like proteins had been found in bilaterians only. The evolutionary origin of p53-like proteins is highly disputed and primordial p53-like proteins are variably thought to protect somatic cells from genotoxic stress. Here we show that ultraviolet (UV) irradiation at low levels selectively induces programmed cell death in early gametes but not somatic cells of adult N. vectensis polyps. We demonstrate with RNA interference that nvp63 mediates this cell death in vivo. Nvp63 is the most archaic member of three p53-like proteins found in N. vectensis and in congruence with all known p53-like proteins, nvp63 binds to the vertebrate p53 DNA recognition sequence and activates target gene transcription in vitro. A transactivation inhibitory domain at its C-terminus with high homology to the vertebrate p63 may regulate nvp63 on a molecular level. The genotoxic stress induced and nvp63 mediated apoptosis in N. vectensis gametes reveals an evolutionary ancient germ cell protective pathway which relies on p63-like proteins and is conserved from cnidarians to vertebrates. PMID:17848985

  4. Effects of Cd, Co, Cu, Ni and Zn on asexual reproduction and early development of the tropical sea anemone Aiptasia pulchella.

    PubMed

    Howe, Pelli L; Reichelt-Brushett, Amanda J; Clark, Malcolm W

    2014-11-01

    Currently few studies present sub-lethal toxicity data for tropical marine species, and there are no routine toxicity tests using marine cnidarians. The symbiotic sea anemone Aiptasia pulchella has been identified as a useful species for ecotoxicological risk assessment, and would provide a tropical marine cnidarian representative. Chronic sub-lethal toxicity tests assessing the effects of 28-day trace metal exposure on asexual reproduction in A. pulchella were investigated, and concentration-dependant reductions in the number of offspring that were produced were evident for all metal exposures. Metal concentration estimates causing 50% reductions in the numbers of asexually-reproduced juveniles after 28-day exposures (28-day effect concentrations 50%: EC50s) were 14 µg/L for copper, 63 µg/L for zinc, 107 µg/L for cobalt, 145 µg/L for cadmium, and 369 µg/L for nickel. Slightly higher 28-day EC50s of 16 µg/L for copper, 192 µg/L for zinc, 172 µg/L for cobalt, 185 µg/L for cadmium, and 404 µg/L for nickel exposures and were estimated based on reductions in the total number of live developed and undeveloped offspring. These sensitive and chronic sub-lethal toxicity estimates help fill the knowledge gap related to metal effects on cnidarians over longer exposure periods, and this newly-developed bioassay may provide a much needed tool for ecotoxicological risk assessment relevant to tropical marine environments. PMID:25119449

  5. The 2.0-A crystal structure of eqFP611, a far red fluorescent protein from the sea anemone Entacmaea quadricolor.

    PubMed

    Petersen, Jan; Wilmann, Pascal G; Beddoe, Travis; Oakley, Aaron J; Devenish, Rodney J; Prescott, Mark; Rossjohn, Jamie

    2003-11-01

    We have crystallized and subsequently determined to 2.0-A resolution the crystal structure of eqFP611, a far red fluorescent protein from the sea anemone Entacmaea quadricolor. The structure of the protomer, which adopts a beta-can topology, is similar to that of the related monomeric green fluorescent protein (GFP). The quaternary structure of eqFP611, a tetramer exhibiting 222 symmetry, is similar to that observed for the more closely related red fluorescent protein DsRed and the chromoprotein Rtms5. The unique chromophore sequence (Met63-Tyr64-Gly65) of eqFP611, adopts a coplanar and trans conformation within the interior of the beta-can fold. Accordingly, the eqFP611 chromophore adopts a significantly different conformation in comparison to the chromophore conformation observed in GFP, DsRed, and Rtms5. The coplanar chromophore conformation and its immediate environment provide a structural basis for the far red, highly fluorescent nature of eqFP611. The eqFP611 structure extends our knowledge on the range of conformations a chromophore can adopt within closely related members of the green fluorescent protein family. PMID:12909624

  6. Production of a reference transcriptome and transcriptomic database (EdwardsiellaBase) for the lined sea anemone, Edwardsiella lineata, a parasitic cnidarian

    PubMed Central

    2014-01-01

    Background The lined sea anemone Edwardsiella lineata is an informative model system for evolutionary-developmental studies of parasitism. In this species, it is possible to compare alternate developmental pathways leading from a larva to either a free-living polyp or a vermiform parasite that inhabits the mesoglea of a ctenophore host. Additionally, E. lineata is confamilial with the model cnidarian Nematostella vectensis, providing an opportunity for comparative genomic, molecular and organismal studies. Description We generated a reference transcriptome for E. lineata via high-throughput sequencing of RNA isolated from five developmental stages (parasite; parasite-to-larva transition; larva; larva-to-adult transition; adult). The transcriptome comprises 90,440 contigs assembled from >15 billion nucleotides of DNA sequence. Using a molecular clock approach, we estimated the divergence between E. lineata and N. vectensis at 215–364 million years ago. Based on gene ontology and metabolic pathway analyses and gene family surveys (bHLH-PAS, deiodinases, Fox genes, LIM homeodomains, minicollagens, nuclear receptors, Sox genes, and Wnts), the transcriptome of E. lineata is comparable in depth and completeness to N. vectensis. Analyses of protein motifs and revealed extensive conservation between the proteins of these two edwardsiid anemones, although we show the NF-?B protein of E. lineata reflects the ancestral structure, while the NF-?B protein of N. vectensis has undergone a split that separates the DNA-binding domain from the inhibitory domain. All contigs have been deposited in a public database (EdwardsiellaBase), where they may be searched according to contig ID, gene ontology, protein family motif (Pfam), enzyme commission number, and BLAST. The alignment of the raw reads to the contigs can also be visualized via JBrowse. Conclusions The transcriptomic data and database described here provide a platform for studying the evolutionary developmental genomics of a derived parasitic life cycle. In addition, these data from E. lineata will aid in the interpretation of evolutionary novelties in gene sequence or structure that have been reported for the model cnidarian N. vectensis (e.g., the split NF-?B locus). Finally, we include custom computational tools to facilitate the annotation of a transcriptome based on high-throughput sequencing data obtained from a “non-model system.” PMID:24467778

  7. Crustaceans associated with Cnidaria, Bivalvia, Echinoidea and Pisces at São Tomé and Príncipe islands

    Microsoft Academic Search

    PETER WIRTZ

    Symbiotic crustaceans were searched for at sea anemones (Actiniaria), encrusting anemones (Zoantharia), horny coral (Gorgonaria), black coral (Antipatharia), bivalves (Bivalvia), and sea urchins (Echinoidea) at São Tomé and Príncipe Islands (Gulf of Guinea, eastern central Atlantic). Sixteen species of crustaceans were found in association with these invertebrate hosts; eleven of them were new records for the area and two species,

  8. Different visible colors and green fluorescence were obtained from the mutated purple chromoprotein isolated from sea anemone.

    PubMed

    Chiang, Cheng-Yi; Chen, Yi-Lin; Tsai, Huai-Jen

    2014-08-01

    Green fluorescent protein (GFP)-like proteins have been studied with the aim of developing fluorescent proteins. Since the property of color variation is understudied, we isolated a novel GFP-like chromoprotein from the carpet anemone Stichodactyla haddoni, termed shCP. Its maximum absorption wavelength peak (?(max)) is located at 574 nm, resulting in a purple color. The shCP protein consists of 227 amino acids (aa), sharing 96 % identity with the GFP-like chromoprotein of Heteractis crispa. We mutated aa residues to examine any alteration in color. When E63, the first aa of the chromophore, was replaced by serine (E63S), the ?(max) of the mutated protein shCP-E63S was shifted to 560 nm and exhibited a pink color. When Q39, T194, and I196, which reside in the surrounding 5 Å of the chromophore's microenvironment, were mutated, we found that (1) the ?(max) of the mutated protein shCP-Q39S was shifted to 518 nm and exhibited a red color, (2) shCP-T194I exhibited a purple-blue color, and (3) an additional mutation at I196H of the mutated protein shCP-E63L exhibited green fluorescence. In contrast, when the aa located neither at the chromophore nor within its microenvironment were mutated, the resultant proteins shCP-L122H, -E138G, -S137D, -T95I, -D129N, -T194V, -E138Q, -G75E, -I183V, and -I70V never altered their purple color, suggesting that mutations at the shCP chromophore and the surrounding 5 Å microenvironment mostly control changes in color expression or cause fluorescence to develop. Additionally, we found that the cDNAs of shCP and its mutated varieties are faithfully and stably expressed both in Escherichia coli and zebrafish embryos. PMID:24488042

  9. Detrimental effects of host anemone bleaching on anemonefish populations

    Microsoft Academic Search

    P. Saenz-Agudelo; G. P. Jones; S. R. Thorrold; S. Planes

    2011-01-01

    Coral bleaching and related reef degradation have caused significant declines in the abundance of reef-associated fishes.\\u000a Most attention on the effects of bleaching has focused on corals, but bleaching is also prevalent in other cnidarians, including\\u000a sea anemones. The consequences of anemone bleaching are unknown, and the demographic effects of bleaching on associated fish\\u000a recruitment, survival, and reproduction are poorly

  10. Giant Caribbean Anemone (Condylactis gigantea)

    USGS Multimedia Gallery

    Condylactis gigantea fluourescing on rocks. The anemones are in a tank illuminated by ultraviolet (black) light. The anemones absorb the invisible ultraviolet light and reflect it back as visible bright green light....

  11. The specificity of Av3 sea anemone toxin for arthropods is determined at linker DI/SS2-S6 in the pore module of target sodium channels.

    PubMed

    Gur Barzilai, Maya; Kahn, Roy; Regev, Noa; Gordon, Dalia; Moran, Yehu; Gurevitz, Michael

    2014-10-15

    Av3 is a peptide neurotoxin from the sea anemone Anemonia viridis that shows specificity for arthropod voltage-gated sodium channels (Navs). Interestingly, Av3 competes with a scorpion ?-toxin on binding to insect Navs and similarly inhibits the inactivation process, and thus has been classified as 'receptor site-3 toxin', although the two peptides are structurally unrelated. This raises questions as to commonalities and differences in the way both toxins interact with Navs. Recently, site-3 was partly resolved for scorpion ?-toxins highlighting S1-S2 and S3-S4 external linkers at the DIV voltage-sensor module and the juxtaposed external linkers at the DI pore module. To uncover channel determinants involved in Av3 specificity for arthropods, the toxin was examined on channel chimaeras constructed with the external linkers of the mammalian brain Nav1.2a, which is insensitive to Av3, in the background of the Drosophila DmNav1. This approach highlighted the role of linker DI/SS2-S6, adjacent to the channel pore, in determining Av3 specificity. Point mutagenesis at DI/SS2-S6 accompanied by functional assays highlighted Trp404 and His405 as a putative point of Av3 interaction with DmNav1. His405 conservation in arthropod Navs compared with tyrosine in vertebrate Navs may represent an ancient substitution that explains the contemporary selectivity of Av3. Trp404 and His405 localization near the membrane surface and the hydrophobic bioactive surface of Av3 suggest that the toxin possibly binds at a cleft by DI/S6. A partial overlap in receptor site-3 of both toxins nearby DI/S6 may explain their binding competition capabilities. PMID:25055135

  12. Phylum Cnidaria Origin of Diversity

    E-print Network

    Cochran-Stafira, D. Liane

    1 Phylum Cnidaria Origin of Diversity How has so much diversity been possible in the Phylum Cnidaria 1. Polyp and medusa forms ­ Provide the basic diversity by offering two different ways of life diversity been possible in the Phylum Cnidaria 2. Colony formation ­ Most common results of budding ability

  13. Insights into the Toxicological Properties of a Low Molecular Weight Fraction from Zoanthus sociatus (Cnidaria)

    PubMed Central

    Domínguez-Pérez, Dany; Diaz-Garcia, Carlos Manlio; García-Delgado, Neivys; Sierra-Gómez, Yusvel; Castañeda, Olga; Antunes, Agostinho

    2013-01-01

    The phylum Cnidaria is an ancient group of venomous animals, specialized in the production and delivery of toxins. Many species belonging to the class Anthozoa have been studied and their venoms often contain a group of peptides, less than 10 kDa, that act upon ion channels. These peptides and their targets interact with high affinity producing neurotoxic and cardiotoxic effects, and even death, depending on the dose and the administration pathway. Zoanthiniaria is an order of the Subclass Hexacorallia, class Anthozoa, and unlike sea anemone (order Actiniaria), neither its diversity of toxins nor the in vivo effects of the venoms has been exhaustively explored. In this study we assessed some toxicological tests on mice with a low molecular weight fraction obtained by gel filtration in Sephadex G-50 from Zoanthus sociatus crude extract. The gel filtration chromatogram at 280 nm revealed two major peaks, the highest absorbance corresponding to the low molecular weight fraction. The toxicological effects seem to be mostly autonomic and cardiotoxic, causing death in a dose dependent manner with a LD50 of 792 ?g/kg. Moreover, at a dose of 600 ?g/kg the active fraction accelerated the KCl-induced lethality in mice. PMID:23945599

  14. Two Alleles of NF-?B in the Sea Anemone Nematostella vectensis Are Widely Dispersed in Nature and Encode Proteins with Distinct Activities

    PubMed Central

    Sullivan, James C.; Wolenski, Francis S.; Reitzel, Adam M.; French, Courtney E.; Traylor-Knowles, Nikki; Gilmore, Thomas D.; Finnerty, John R.

    2009-01-01

    Background NF-?B is an evolutionarily conserved transcription factor that controls the expression of genes involved in many key organismal processes, including innate immunity, development, and stress responses. NF-?B proteins contain a highly conserved DNA-binding/dimerization domain called the Rel homology domain. Methods/Principal Findings We characterized two NF-?B alleles in the sea anemone Nematostella vectensis that differ at nineteen single-nucleotide polymorphisms (SNPs). Ten of these SNPs result in amino acid substitutions, including six within the Rel homology domain. Both alleles are found in natural populations of Nematostella. The relative abundance of the two NF-?B alleles differs between populations, and departures from Hardy-Weinberg equilibrium within populations indicate that the locus may be under selection. The proteins encoded by the two Nv-NF-?B alleles have different molecular properties, in part due to a Cys/Ser polymorphism at residue 67, which resides within the DNA recognition loop. In nearly all previously characterized NF-?B proteins, the analogous residue is fixed for Cys, and conversion of human RHD proteins from Cys to Ser at this site has been shown to increase DNA-binding ability and increase resistance to inhibition by thiol-reactive compounds. However, the naturally-occurring Nematostella variant with Cys at position 67 binds DNA with a higher affinity than the Ser variant. On the other hand, the Ser variant activates transcription in reporter gene assays more effectively, and it is more resistant to inhibition by a thiol-reactive compound. Reciprocal Cys<->Ser mutations at residue 67 of the native Nv-NF-?B proteins affect DNA binding as in human NF-?B proteins, e.g., a Cys->Ser mutation increases DNA binding of the native Cys variant. Conclusions/Significance These results are the first demonstration of a naturally occurring and functionally significant polymorphism in NF-?B in any species. The functional differences between these alleles and their uneven distribution in the wild suggest that different genotypes could be favored in different environments, perhaps environments that vary in their levels of peroxides or thiol-reactive compounds. PMID:19806194

  15. Pachyseris inattesa sp. n. (Cnidaria, Anthozoa, Scleractinia): a new reef coral species from the Red Sea and its phylogenetic relationships

    PubMed Central

    Terraneo, Tullia I.; Berumen, Michael L.; Arrigoni, Roberto; Waheed, Zarinah; Bouwmeester, Jessica; Caragnano, Annalisa; Stefani, Fabrizio; Benzoni, Francesca

    2014-01-01

    Abstract A new scleractinian coral species, Pachyseris inattesa sp. n., is described from the Red Sea. Despite a superficial resemblance with some species in the agariciid genus Leptoseris with which it has been previously confused, P. inattesa sp. n. has micro-morphological characters typical of the genus Pachyseris. This genus, once part of the Agariciidae, is comprised of five extant species and is widely distributed throughout the tropical Indo-Pacific. It is currently incertae sedis as a result of recent molecular analysis and appears to be closely related to the Euphylliidae. A molecular phylogenetic reconstruction including P. inattesa sp. n., the genus type species P. rugosa, and P. speciosa, all present in the Red Sea, was performed using the mitochondrial intergenic spacer between COI and 16S-rRNA. The results confirm that P. inattesa sp. n. is a monophyletic lineage closely related to the other Pachyseris species examined. PMID:25152672

  16. Phylogenetic Relationships within the Class Anthozoa (Phylum Cnidaria) Based on Nuclear 18S rDNA Sequences

    Microsoft Academic Search

    Ewann A. Berntson; Scott C. France; Lauren S. Mullineaux

    1999-01-01

    Taxonomic relationships within the corals and anemones (Phylum Cnidaria: Class Anthozoa) are based upon few morphological characters. The significance of any given character is debatable, and there is little fossil record available for deriving evolutionary relationships. We analyzed complete 18S ribosomal sequences to examine subclass-level and ordinal-level organization within the Anthozoa. We suggest that the Subclass Ceriantipatharia is not an

  17. Taxonomic, Spatial and Temporal Patterns of Bleaching in Anemones Inhabited by Anemonefishes

    PubMed Central

    Hobbs, Jean-Paul A.; Frisch, Ashley J.; Ford, Benjamin M.; Thums, Michele; Saenz-Agudelo, Pablo; Furby, Kathryn A.; Berumen, Michael L.

    2013-01-01

    Background Rising sea temperatures are causing significant destruction to coral reef ecosystems due to coral mortality from thermally-induced bleaching (loss of symbiotic algae and/or their photosynthetic pigments). Although bleaching has been intensively studied in corals, little is known about the causes and consequences of bleaching in other tropical symbiotic organisms. Methodology/Principal Findings This study used underwater visual surveys to investigate bleaching in the 10 species of anemones that host anemonefishes. Bleaching was confirmed in seven anemone species (with anecdotal reports of bleaching in the other three species) at 10 of 19 survey locations spanning the Indo-Pacific and Red Sea, indicating that anemone bleaching is taxonomically and geographically widespread. In total, bleaching was observed in 490 of the 13,896 surveyed anemones (3.5%); however, this percentage was much higher (19–100%) during five major bleaching events that were associated with periods of elevated water temperatures and coral bleaching. There was considerable spatial variation in anemone bleaching during most of these events, suggesting that certain sites and deeper waters might act as refuges. Susceptibility to bleaching varied between species, and in some species, bleaching caused reductions in size and abundance. Conclusions/Significance Anemones are long-lived with low natural mortality, which makes them particularly vulnerable to predicted increases in severity and frequency of bleaching events. Population viability will be severely compromised if anemones and their symbionts cannot acclimate or adapt to rising sea temperatures. Anemone bleaching also has negative effects to other species, particularly those that have an obligate relationship with anemones. These effects include reductions in abundance and reproductive output of anemonefishes. Therefore, the future of these iconic and commercially valuable coral reef fishes is inextricably linked to the ability of host anemones to cope with rising sea temperatures associated with climate change. PMID:23951056

  18. Metamorphosis in the Cnidaria

    Microsoft Academic Search

    Werner A. Müller; Thomas Leitz

    2002-01-01

    The free-living stages of sedentary organisms are an adaptation that enables immobile species to exploit scattered or transient ecological niches. In the Cnidaria the task of prospecting for and identifying a congenial habitat is consigned to tiny planula larvae or larva-like buds, stages that actually transform into the sessile polyp. However, the sensory equipment of these larvae does not qualify

  19. Phylum Cnidaria Introduction

    E-print Network

    Cochran-Stafira, D. Liane

    live. #12;7 Cnidocyte before discharge. Cnidocil and operculum with the coiled tube still contained found in the tube- building anemones, · used to "spin" the fiberglass-like tube in which these animals with discharged nematocyst Discharged cnidocyte showing the everted stinging tube cnidocyte Mechanism of Firing

  20. Ecological and morphological characteristics of Ephelota gemmipara (Ciliophora, Suctoria), epibiontic on Eudendrium racemosum (Cnidaria, Hydrozoa) from the Adriatic Sea.

    PubMed

    Tazioli, Silvia; Di Camillo, Cristina Gioia

    2013-11-01

    The relationship between the suctorian Ephelota gemmipara and the large hydroid Eudendrium racemosum from the North Adriatic Sea has been studied over its full annual cycle. Ephelota gemmipara settles on the perisarc of the hydroid, usually close to the hydranths in order to exploit the hydroid's food discharges. The life cycle of E. gemmipara is influenced by temperature variations and by its relationship with the host. The hydroid shows an active phase in the summer, and it gets through the adverse winter season forming resting stages. In April, when temperature increases, the hydroid starts its active phase and it is colonized by suctorians. From May to September the suctorians produce multiple buds (swarmers) that detach from the parental cells to settle on an Eudendrium colony. The abundance of the suctorian peaks in September, with more than 1.2 million ind. m(-2). Their proliferation coincides with the maximal abundance of their host and the highest water temperatures. On the contrary, sexual reproduction and the encystment occur when the temperature and the abundance of E. racemosum decrease. Lastly, we also report the presence of symbionts such as bacteria and the parasitic protozoans Tachyblaston ephelotensis and Enigmocoma acinetarum. PMID:23711377

  1. The differentiation of nematocysts and associated structures in the cnidaria

    Microsoft Academic Search

    Jane A. Westfall

    1966-01-01

    The differentiation of nematocysts and associated structures in the tentacles of the sea anemone Metridium senile fimbriatum and in the tentacles of medusae of the hydroid Obelia longissima was studied by electron microscopy. Stages in the morphogenesis of nematocysts are: 1. transformation of an interstitial cell into a cnidoblast in which the primordium of the nematocyst arises from Golgi vacuoles,

  2. Evolutionary crossroads in developmental biology: Cnidaria

    PubMed Central

    Technau, Ulrich; Steele, Robert E.

    2011-01-01

    There is growing interest in the use of cnidarians (corals, sea anemones, jellyfish and hydroids) to investigate the evolution of key aspects of animal development, such as the formation of the third germ layer (mesoderm), the nervous system and the generation of bilaterality. The recent sequencing of the Nematostella and Hydra genomes, and the establishment of methods for manipulating gene expression, have inspired new research efforts using cnidarians. Here, we present the main features of cnidarian models and their advantages for research, and summarize key recent findings using these models that have informed our understanding of the evolution of the developmental processes underlying metazoan body plan formation. PMID:21389047

  3. Two new species of deep-water Corallimorpharia (Cnidaria: Anthozoa) from the Northeast Pacific, *Corallimorphus denhartogi* and *C. pilatus*

    E-print Network

    Fautin, Daphne G.; White, Tracy R.; Pearson, Katherine E.

    2002-04-01

    Corallimorpharia is currently considered an order of hexacorallian anthozoans. Being skeletonless, its members are sometimes referred to as sea anemones, but they are morphologically more similar to members of Scleractinia ...

  4. Understanding the molecular basis of toxin promiscuity: the analgesic sea anemone peptide APETx2 interacts with acid-sensing ion channel 3 and hERG channels via overlapping pharmacophores.

    PubMed

    Jensen, Jonas E; Cristofori-Armstrong, Ben; Anangi, Raveendra; Rosengren, K Johan; Lau, Carus H Y; Mobli, Mehdi; Brust, Andreas; Alewood, Paul F; King, Glenn F; Rash, Lachlan D

    2014-11-13

    The sea anemone peptide APETx2 is a potent and selective blocker of acid-sensing ion channel 3 (ASIC3). APETx2 is analgesic in a variety of rodent pain models, but the lack of knowledge of its pharmacophore and binding site on ASIC3 has impeded development of improved analogues. Here we present a detailed structure-activity relationship study of APETx2. Determination of a high-resolution structure of APETx2 combined with scanning mutagenesis revealed a cluster of aromatic and basic residues that mediate its interaction with ASIC3. We show that APETx2 also inhibits the off-target hERG channel by reducing the maximal current amplitude and shifting the voltage dependence of activation to more positive potentials. Electrophysiological screening of selected APETx2 mutants revealed partial overlap between the surfaces on APETx2 that mediate its interaction with ASIC3 and hERG. Characterization of the molecular basis of these interactions is an important first step toward the rational design of more selective APETx2 analogues. PMID:25337890

  5. Comparative depth distribution of corallimorpharians and scleractinians (Cnidaria: Anthozoa)

    E-print Network

    Fautin, Daphne G.; Guinotte, John M.; Orr, James C.

    2009-11-17

    · Scleractinia · Corals · Sea anemones Resale or republication not permitted without written consent of the publisher OPEN ACCESS Contribution to the Theme Section ‘Conservation and management of deep-sea corals and coral reefs’ Mar Ecol Prog Ser 397: 63... of the Challenger Expedition include 2 chapters on sclerac- tinians, one by Moseley (1881) on deep-sea corals and one by Quelch (1886) on shallow-water, reef-building corals. Although most specimens dealt with in the chapter by Quelch (1886) seem to have been...

  6. Ammonia flux, physiological parameters, and Symbiodinium diversity in the anemonefish symbiosis on Red Sea coral reefs

    Microsoft Academic Search

    Modi Roopin; Daniel J. Thornhill; Scott R. Santos; Nanette E. Chadwick

    2011-01-01

    Despite the ecological importance of anemonefish symbioses, little is known about how nutritional contributions from anemonefish\\u000a interact with sea anemone physiology and Symbiodinium (endosymbiotic dinoflagellate) genetic identity under field conditions. On Red Sea coral reefs, we measured variation in\\u000a ammonia concentrations near anemones, excretion rates of anemonefish, physiological parameters of anemones and Symbiodinium, and genetic identity of Symbiodinium within anemones.

  7. Invertebrate introductions in marine habitats: two species of hydromedusae (Cnidaria) native to the Black Sea, Maeotias inexspectata and Blackfordia virginica , invade San Francisco Bay

    Microsoft Academic Search

    C. E. Mills; F. Sommer

    1995-01-01

    The hydrozoans Maeotias inexspectata Ostroumoff, 1896 and Blackfordia virginica Mayer, 1910, believed to be native to the Black Sea (i.e. Sarmatic) and resident in a variety of estuarine habitats worldwide, were found as introduced species in the Petaluma River and Napa River, California, in 1992 and 1993. These rivers are mostly-estuarine tributaries that flow into north San Francisco Bay. Both

  8. Sympagohydra tuuli (Cnidaria, Hydrozoa): Wrst report from sea ice of the central Arctic Ocean and insights into histology, reproduction and locomotion

    Microsoft Academic Search

    Stefan Siebert; Friederike Anton-Erxleben; Rainer Kiko; Maike Kramer

    2008-01-01

    Various cnidarians have adapted their life style to interstitial habitats of marine sediments. Recently, for the Wrst time a hydroid was reported from the interstitial brine channel system of Arctic fast ice. Due to its derived fea- tures, the new genus and species Sympagohydra tuuli was introduced. Here we describe Wndings of S. tuuli in sea ice at several sites

  9. Phospholipase A2 in Cnidaria

    Microsoft Academic Search

    Timo J. Nevalainen; Heikki J. Peuravuori; Ronald J. Quinn; Lyndon E. Llewellyn; John A. H. Benzie; Peter J. Fenner; Ken D. Winkel

    2004-01-01

    Phospholipase A2 (PLA2) is an enzyme present in snake and other venoms and body fluids. We measured PLA2 catalytic activity in tissue homogenates of 22 species representing the classes Anthozoa, Hydrozoa, Scyphozoa and Cubozoa of the phylum Cnidaria. High PLA2 levels were found in the hydrozoan fire coral Millepora sp. (median 735 U\\/g protein) and the stony coral Pocillopora damicornis

  10. Sympagohydra tuuli (Cnidaria, Hydrozoa): first report from sea ice of the central Arctic Ocean and insights into histology, reproduction and locomotion

    Microsoft Academic Search

    Stefan Siebert; Friederike Anton-Erxleben; Rainer Kiko; Maike Kramer

    2009-01-01

    Various cnidarians have adapted their life style to interstitial habitats of marine sediments. Recently, for the first time\\u000a a hydroid was reported from the interstitial brine channel system of Arctic fast ice. Due to its derived features, the new\\u000a genus and species Sympagohydra tuuli was introduced. Here we describe findings of S. tuuli in sea ice at several sites within

  11. Acrorhagi, catch tentacles and sweeper tentacles: a synopsis of ‘aggression’ of actiniarian and scleractinian Cnidaria

    Microsoft Academic Search

    R. B. Williams

    1991-01-01

    Three types of organ (acrorhagi and catch tentacles in sea anemones, and sweeper tentacles in corals) are described with regard to both morphology and ‘aggressive’ function. Species known to possess such organs are listed. Research on the functions of these particular organs is reviewed and some exceptions to their usual behaviour patterns are highlighted. Further research on allogeneic recognition might

  12. Movements of anemones symbiotic with hermit crabs: Effects of light, gravity, flow and conspecifics

    Microsoft Academic Search

    Dan Rittschof; Sarah M. McFarland; Erin M. Stocker; W. Randall Brooks

    1999-01-01

    Anemones, Calliactis tricolor (Le Sueur, 1817), are common symbionts associated with several genera of hermit crabs on the South East and Gulf Coasts of the United States. Anemones are reported to be mutualistic symbionts. Crabs protect anemones from anemone predators and anemones protect crabs by stinging crab predators. Previous studies show protection afforded by anemones is dependent upon their location

  13. Interannual variability, growth, reproduction and feeding of Pelagia noctiluca (Cnidaria: Scyphozoa) in the Straits of Messina (Central Mediterranean Sea): Linkages with temperature and diet

    NASA Astrophysics Data System (ADS)

    Rosa, S.; Pansera, M.; Granata, A.; Guglielmo, L.

    2013-02-01

    To identify some of the possible environmental factors stimulating the increasingly frequent outbreaks of the scyphomedusa Pelagia noctiluca in the Straits of Messina, we investigated its abundance, growth, reproduction and feeding over a 4-year period, from 2007 to 2011, at two coastal sites. Using either field investigations and manipulative experiments we show that, among the various factors considered, shifts in water temperature (influencing medusae metabolism, growth and reproduction rates) and the size structure of the zooplankton community (their natural preys) can promote the proliferation of P. noctiluca. In particular, we show that increased temperature let jellyfishes to grow more rapidly and reach exceptional sizes. We also report a peculiar opportunistic behavior of P. noctiluca, which makes this species a potentially strong competitor in the pelagic trophic web of the Straits ecosystem. We therefore propose that more frequent P. noctiluca outbreaks stimulated by increasing sea surface temperature and shifts in their prey availability and composition would become, in the near future, a major cause of ecosystem shift.

  14. StellaBase: The Nematostella vectensis Genomics Database

    E-print Network

    Finnerty, John R.

    , it is necessary to consult non-bilaterian outgroups taxa such as the phylum Cnidaria (sea anemones, corals, hydras is the first member of the basal animal phylum Cnidaria, and the first basal animal generally, to have its in the laboratory (8­10). An important advantage of Nematostella and other Cnidaria relative to the major animal

  15. Evolutionary Diversification of Banded Tube-Dwelling Anemones (Cnidaria; Ceriantharia; Isarachnanthus) in the Atlantic Ocean

    PubMed Central

    Stampar, Sergio N.; Maronna, Maximiliano M.; Vermeij, Mark J. A.; Silveira, Fabio L. d.; Morandini, André C.

    2012-01-01

    The use of molecular data for species delimitation in Anthozoa is still a very delicate issue. This is probably due to the low genetic variation found among the molecular markers (primarily mitochondrial) commonly used for Anthozoa. Ceriantharia is an anthozoan group that has not been tested for genetic divergence at the species level. Recently, all three Atlantic species described for the genus Isarachnanthus of Atlantic Ocean, were deemed synonyms based on morphological simmilarities of only one species: Isarachnanthus maderensis. Here, we aimed to verify whether genetic relationships (using COI, 16S, ITS1 and ITS2 molecular markers) confirmed morphological affinities among members of Isarachnanthus from different regions across the Atlantic Ocean. Results from four DNA markers were completely congruent and revealed that two different species exist in the Atlantic Ocean. The low identification success and substantial overlap between intra and interspecific COI distances render the Anthozoa unsuitable for DNA barcoding, which is not true for Ceriantharia. In addition, genetic divergence within and between Ceriantharia species is more similar to that found in Medusozoa (Hydrozoa and Scyphozoa) than Anthozoa and Porifera that have divergence rates similar to typical metazoans. The two genetic species could also be separated based on micromorphological characteristics of their cnidomes. Using a specimen of Isarachnanthus bandanensis from Pacific Ocean as an outgroup, it was possible to estimate the minimum date of divergence between the clades. The cladogenesis event that formed the species of the Atlantic Ocean is estimated to have occured around 8.5 million years ago (Miocene) and several possible speciation scenarios are discussed. PMID:22815928

  16. Analysis of complete mitochondrial DNA sequences of three members of the Montastraea annularis coral species complex (Cnidaria, Anthozoa, Scleractinia)

    Microsoft Academic Search

    Hironobu Fukami; Nancy Knowlton

    2005-01-01

    Complete mitochondrial nucleotide sequences of two individuals each of Montastraea annularis, Montastraea faveolata, and Montastraea franksi were determined. Gene composition and order differed substantially from the sea anemone Metridium senile, but were identical to that of the phylogenetically distant coral genus Acropora. However, characteristics of the non-coding regions differed between the two scleractinian genera. Among members of the M. annularis

  17. The spermatozoon of Carybdea marsupialis (Cubozoa, Cnidaria)

    Microsoft Academic Search

    A. CORBELLI; M. AVIAN; R. MAROTTA; M. FERRAGUTI

    2003-01-01

    The spermatozoon of Carybdea marsupialis (Cnidaria, Cubozoa, Carybdeidae) is a primitive sperm with a short pear-shaped head and a long tail. The head contains a pyriform nucleus, six mitochondria, two centrioles aligned on the major axis of the sperm, and an anchoring apparatus formed by a complex pericentriolar system and a pyramid-like appendix (spur). The pericentriolar system is formed by

  18. A comparative analysis of the photobiology of zooxanthellae and zoochlorellae symbiotic with the temperate clonal anemone Anthopleura elegantissima (Brandt). III. Seasonal effects of natural light and temperature on photosynthesis and respiration

    Microsoft Academic Search

    E. Alan Verde; L. R. McCloskey

    2007-01-01

    The sea anemone Anthopleura elegantissima hosts two phylogenetically different symbiotic microalgae, a dinoflagellate Symbiodinium (zooxanthellae, ZX) and a chlorophyte (zoochlorellae, ZC). The photosynthetic productivity (P), respiration (R), and contribution\\u000a of algal carbon translocated to the host (CZAR) in response to a year’s seasonal ambient changes of natural light and temperature\\u000a are documented for both ZX- and ZC-bearing anemones. Light and

  19. On Some Features of Early Embryonic Development Stages of Cnidaria

    Microsoft Academic Search

    Z. S. Kaufman

    2004-01-01

    Division of the life cycle of Cnidaria (except for Anthozoa) into two independent generations, polypoid and medusoid, i.e., metagenesis, is considered to be unjustified. Like other Metazoa, their life cycle can be divided into three periods: embryonic, postembryonic, and definitive, i.e., according to the age [9, 10]. An important feature of Cnidaria is the transition of some postembryonic stages to

  20. Statolith formation in Cnidaria: effects of cadmium on Aurelia statoliths

    NASA Technical Reports Server (NTRS)

    Spangenberg, D. B.

    1986-01-01

    Statolith formation in Cnidaria was reviewed with an emphasis on Aurelia statoliths. The review provides information on the chemical composition, mechanisms of initiation of mineralization, and effects of environmental factors on Cnidarian statolith formation. Environmental factors discussed included modified sea water ingredients, X-irradiation, clinostat rotation, and petroleum oil ingredients. A detailed account of the effects of cadmium on mineralization and demineralization of Aurelia statoliths is given. Cadmium at dosages of 2 to 4 micromoles significantly reduces statolith numbers in developing ephyrae. At a dosage of 3 micromoles, cadmium accelerates statolith loss in unfed ephyrae studied at 4 and 8 days following ephyrae release from strobilae. Cadmium, therefore, is shown to reduce statolith numbers in developing ephyrae and to cause greater reduction of statolith numbers in unfed ephyrae after 4 and 8 days than occurred in controls. Supplementation of Cd(2+)-containing artificial sea water (ASW) with calcium (3X and 5X ASW calcium content) results in higher numbers of statoliths at day 4 as compared with cadmium-treated ephyrae. At 8 days only the 5X calcium supplemented ASW is effective in enhancing statolith numbers in Cd(2+)-treated ephyrae. These results suggest that cadmium competes in some manner with calcium at the mineralizing sites of Aurelia.

  1. Intron retention as a posttranscriptional regulatory mechanism of neurotoxin expression at early life stages of the starlet anemone Nematostella vectensis.

    PubMed

    Moran, Yehu; Weinberger, Hagar; Reitzel, Adam M; Sullivan, James C; Kahn, Roy; Gordon, Dalia; Finnerty, John R; Gurevitz, Michael

    2008-07-11

    Sea anemones use an arsenal of peptide neurotoxins accumulated in special stinging cells (nematocytes) for defense and predation. Intriguingly, genomic analysis of Nematostella vectensis revealed only a single toxin, Nv1 (N. vectensis toxin 1), encoded by multiple extremely conserved genes. We examined the toxic potential of Nv1 and whether it is produced by the three developmental stages (embryo, planula, and polyp) of Nematostella. Nv1 was expressed in recombinant form and, similarly to Type I sea anemone toxins, inhibited the inactivation of voltage-gated sodium channels. However, in contrast to the other toxins, Nv1 revealed high specificity for insect over mammalian voltage-gated sodium channels. Transcript analysis indicated that multiple Nv1 loci are transcribed at all developmental stages of N. vectensis, whereas splicing of these transcripts is restricted to the polyp stage. This finding suggests that regulation of Nv1 synthesis is posttranscriptional and that the embryo and planula stages do not produce the Nv1 toxin. This rare phenomenon of intron retention at the early developmental stages is intriguing and raises the question as to the mechanism enabling such differential expression in sea anemones. PMID:18538344

  2. Calibration of stable oxygen isotopes in Siderastrea radians (Cnidaria:Scleractinia): Implications for slow-growing corals

    E-print Network

    Swart, Peter K.

    Calibration of stable oxygen isotopes in Siderastrea radians (Cnidaria:Scleractinia): Implications. Swart, and R. E. Dodge (2006), Calibration of stable oxygen isotopes in Siderastrea radians (Cnidaria

  3. Deep-water Hydrozoa (Cnidaria: Medusozoa) in the Sea of Japan, collected during the 51st Cruise of R/V Akademik M.A. Lavrentyev, with description Opercularella angelikae, sp. nov.

    NASA Astrophysics Data System (ADS)

    Stepanjants, Sofia D.

    2013-02-01

    A report is given about Hydrozoa collected at depths between 455 and 3666 m in the Sea of Japan during the Russian-German expedition on R/V Akademik M.A. Lavrentyev. Ten species were found, with four of them being typical bathyal-abyssal and abyssal zones. A new species, Opercularella angelikae, is described, and it was the dominant hydroid in samples from 970 to 3660 m. Four eurybathic species characteristics of the Sea of Japan were sampled between 455 and 582 m. Abyssal (pseudoabyssal after Andriashev, 1979) hydroid fauna in the Sea of Japan is reported. The hypothesis that an exclusively deep-water fauna is lacking in abyssal regions of the Sea of Japan is disputed. The author's personal opinion considered concerning the borders of 1000 m between shallow and deep hydrozoan species in the Sea of Japan.

  4. Photosynthetic symbioses in animals

    Microsoft Academic Search

    A. A. Venn; J. E. Loram; A. E. Douglas

    2008-01-01

    Animals acquire photosynthetically-fixed carbon by forming symbioses with algae and cyanobacteria. These associations are widespread in the phyla Por- ifera (sponges) and Cnidaria (corals, sea anemones etc.) but otherwise uncommon or absent from animal phyla. It is suggested that one factor contributing to the distribution of animal symbioses is the morpholog- ically-simple body plan of the Porifera and Cnidaria with

  5. Macrofouling of deep-sea instrumentation after three years at 3690 m depth in the Charlie Gibbs fracture zone, mid-Atlantic ridge, with emphasis on hydroids (Cnidaria: Hydrozoa)

    NASA Astrophysics Data System (ADS)

    Blanco, R.; Shields, M. A.; Jamieson, A. J.

    2013-12-01

    Macrofouling is a common problem when deploying underwater instrumentation for long periods of time. It is a problem which can effect scientific experiments and monitoring missions though the creation of artificial reefs (thus increasing local biological activity) and reduce the quality of scientific data. Macrofouling is an issue typically considered to be restricted to the photic zones and is absent or negligible in the deep sea. To the contrary, the recovery of an accidentally lost deep-sea lander after 3 years submergence at 3960 m on the Mid-Atlantic Ridge (North Atlantic) revealed dense colonisation of macrofouling organisms. These organisms were found attached to all surfaces of the lander regardless of orientation and materials. The occurrence of such deep-sea macrofouling should be carefully investigated given the recent developments in long-term deep-sea observatory networks.

  6. PHYLOGENETIC SYSTEMATICS, TAXONOMY, AND BIOGEOGRAPHY OF JELLYFISH (CNIDARIA: MEDUSOZOA)

    E-print Network

    Bentlage, Bastian

    2012-08-31

    The coastal shelf inhabiting box jellyfish (Cubozoa) represent the smallest class within Cnidaria with some 50 described species. A robust phylogenetic framework had been missing for Cubozoa. Herein, a molecular phylogeny for Cubozoa is presented...

  7. The European athecate hydroids and their medusae (Hydrozoa, Cnidaria): Filifera Part 5

    E-print Network

    Schuchert, Peter

    The European athecate hydroids and their medusae (Hydrozoa, Cnidaria): Filifera Part 5 Peter.Schuchert@ville-ge.ch The European athecate hydroids and their medusae (Hydrozoa, Cnidaria): Filifera Part 5. - This study reviews. Keywords: Cnidaria - marine - Hydrozoa - revision - taxonomy - north- eastern Atlantic - Mediterranean

  8. The European athecate hydroids and their medusae (Hydrozoa, Cnidaria): Capitata Part 1

    E-print Network

    Schuchert, Peter

    The European athecate hydroids and their medusae (Hydrozoa, Cnidaria): Capitata Part 1 Peter.Schuchert@ville-ge.ch The European athecate hydroids and their medusae (Hydrozoa, Cnidaria): Capitata Part 1. - This study reviews used since their original introduction by Haeckel. Keywords: Marine invertebrates - Cnidaria - Hydrozoa

  9. Differential Gene Expression in the Siphonophore Nanomia bijuga (Cnidaria) Assessed with Multiple Next-

    E-print Network

    Dunn, Casey

    Differential Gene Expression in the Siphonophore Nanomia bijuga (Cnidaria) Assessed with Multiple polyps and swimming medusae in the siphonophore Nanomia bijuga (Cnidaria) with a hybrid long (Cnidaria) Assessed with Multiple Next-Generation Sequencing Workflows. PLoS ONE 6(7): e22953. doi:10

  10. The European athecate hydroids and their medusae (Hydrozoa, Cnidaria): Filifera Part 2

    E-print Network

    Schuchert, Peter

    The European athecate hydroids and their medusae (Hydrozoa, Cnidaria): Filifera Part 2 Peter.Schuchert@ville-ge.ch The European athecate hydroids and their medusae (Hydrozoa, Cnidaria): Filifera Part 2. - This study reviews affinis (Hartlaub, 1914). Keywords: Cnidaria - Hydrozoa - Bougainvilliidae - Pandeidae - Cytaeididae

  11. The European athecate hydroids and their medusae (Hydrozoa, Cnidaria): Filifera Part 4

    E-print Network

    Schuchert, Peter

    The European athecate hydroids and their medusae (Hydrozoa, Cnidaria): Filifera Part 4 Peter.Schuchert@ville-ge.ch The European athecate hydroids and their medusae (Hydrozoa, Cnidaria): Filifera Part 4. - This study reviews not replace M. hargitti or M. amboinense. Keywords: Cnidaria - marine - Hydrozoa ­ Eudendriidae - revision

  12. Morphological revision of the genus Aiptasia and the family Aiptasiidae (Cnidaria, Actiniaria, Metridioidea).

    PubMed

    Grajales, Alejandro; Rodríguez, Estefanía

    2014-01-01

    Sea anemones of the genus Aiptasia Gosse, 1858 are conspicuous members of shallow-water environments worldwide and serve as a model system for studies of cnidarian-dinoflagellate symbiosis. However, to date there have been no comprehensive analyses investigating the systematics of the group. In addition, previously published phylogenetic studies of sea anemones have shown that the genus is not monophyletic. Herein we revise the genus Aiptasia and the family Aiptasiidae Carlgren, 1924 using newly-collected material. We find that the formerly-named A. pallida (Agassiz in Verrill, 1864) (now Exaiptasia pallida comb. nov.) encompasses a single, widespread species from the tropics and subtropics; we erect a new genus, Exaiptasia gen. nov., for this species primarily based on cnidae, mode of asexual reproduction and symbionts. We also find morphological evidence that supports splitting A. mutabilis into two species: A. couchii (Cocks, 1851) and A. mutabilis. In addition, we find Bellactis Dube, 1983 (formerly placed within Sagartiidae Gosse, 1858) and Laviactis gen. nov. (formerly known Ragactis Andres, 1883, whose familial placement was previously uncertain) belonging within Aiptasiidae. Aiptasiidae is a morphologically homogeneous family whose members (those species in genera Aiptasia, Aiptasiogeton Schmidt, 1972, Bartholomea Duchassaing de Fombressin & Michelotti, 1864, Bellactis, Exaiptasia gen. nov., and Laviactis gen. nov.) are characterized by ectodermal longitudinal muscles in the distal column, rows of cinclides in mid-column, microbasic b-mastigophores in the column, and acontia with basitrichs and microbasic p-amastigophores. PMID:24990039

  13. Mitochondrial DNA of Hydra attenuata (Cnidaria): A Sequence That Includes an End of One Linear Molecule and the Genes for l-rRNA,

    E-print Network

    Warrior, Rahul

    Mitochondrial DNA of Hydra attenuata (Cnidaria): A Sequence That Includes an End of One Linear linear mitochondrial (mt) DNA molecules of Hydra attenuata (phylum Cnidaria, class Hydrozoa, order distinct helical elements. Key words: Hydra attenuata -- Cnidaria -- Mito- chondrial genes -- Nucleotide

  14. Searching for a Toxic Key to Unlock the Mystery of Anemonefish and Anemone Symbiosis

    PubMed Central

    Nedosyko, Anita M.; Young, Jeanne E.; Edwards, John W.; Burke da Silva, Karen

    2014-01-01

    Twenty-six species of anemonefish of the genera Amphiprion and monospecific Premnas, use only 10 species of anemones as hosts in the wild (Families: Actiniidae, Stichodactylidae and Thalassianthidae). Of these 10 anemone species some are used by multiple species of anemonefish while others have only a single anemonefish symbiont. Past studies have explored the different patterns of usage between anemonefish species and anemone species; however the evolution of this relationship remains unknown and has been little studied over the past decade. Here we reopen the case, comparing the toxicity of crude venoms obtained from anemones that host anemonefish as a way to investigate why some anemone species are used as a host more than others. Specifically, for each anemone species we investigated acute toxicity using Artemia francisca (LC50), haemolytic toxicity using ovine erythrocytes (EC50) and neurotoxicity using shore crabs (Ozius truncatus). We found that haemolytic and neurotoxic activity varied among host anemone species. Generally anemone species that displayed greater haemolytic activity also displayed high neurotoxic activity and tend to be more toxic on average as indicated by acute lethality analysis. An overall venom toxicity ranking for each anemone species was compared with the number of anemonefish species that are known to associate with each anemone species in the wild. Interestingly, anemones with intermediate toxicity had the highest number of anemonefish associates, whereas anemones with either very low or very high toxicity had the fewest anemonefish associates. These data demonstrate that variation in toxicity among host anemone species may be important in the establishment and maintenance of anemonefish anemone symbiosis. PMID:24878777

  15. Hydrocoryne iemanja (Cnidaria), a new species of Hydrozoa with unusual

    E-print Network

    Morandini, Andre C.

    Hydrocoryne iemanja (Cnidaria), a new species of Hydrozoa with unusual mode of asexual reproduction gonads 5­7 days after release. Asexual reproduction by longitudinal fission was observed of cnidarians. Further studies of this process may shed light on the understanding of the evolutionary pathways

  16. Bioindication Potential of Carbonic Anhydrase Activity in Anemones

    E-print Network

    Bermingham, Eldredge

    Bioindication Potential of Carbonic Anhydrase Activity in Anemones and Corals AUBREY L. GILBERT describing coral CA activity for potential application in bioindication. Published by Elsevier Sci- ence Ltd bioindication. While oysters and many other bivalves are predisposed to accumulate heavy metal pollutants

  17. The European athecate hydroids and their medusae (Hydrozoa, Cnidaria): Filifera Part 3

    E-print Network

    Schuchert, Peter

    of Turritopsis polycirrha (Keferstein, 1862). Hydractinia areolata Alder, 1862 is selected as type species belonging to Turritopsis dohrnii (Weismann, 1883). Keywords: Cnidaria - marine - Hydrozoa - Hydractiniidae

  18. STATISTICAL STUDY OF CHROMOSPHERIC ANEMONE JETS OBSERVED WITH HINODE/SOT

    SciTech Connect

    Nishizuka, N. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 229-8510 (Japan); Nakamura, T.; Kawate, T.; Singh, K. A. P.; Shibata, K., E-mail: nishizuka.naoto@jaxa.jp [Kwasan and Hida observatories, Kyoto University, Yamashina, Kyoto 607-8471 (Japan)

    2011-04-10

    The Solar Optical Telescope on board Hinode has revealed numerous tiny jets in all regions of the chromosphere outside of sunspots. A typical chromospheric anemone jet has a cusp-shaped structure and bright footpoint, similar to the shape of an X-ray anemone jet observed previously with the Soft X-ray Telescope on board Yohkoh. The similarity in the shapes of chromospheric and X-ray anemone jets suggests that chromospheric anemone jets are produced as a result of the magnetic reconnection between a small bipole (perhaps a tiny emerging flux) and a pre-existing uniform magnetic field in the lower chromosphere. We examine various chromospheric anemone jets in the solar active region near the solar limb and study the typical features (e.g., length, width, lifetime, and velocity) of the chromospheric anemone jets. Statistical studies show that chromospheric anemone jets have: (1) a typical length {approx}1.0-4.0 Mm, (2) a width {approx}100-400 km, (3) a lifetime {approx}100-500 s, and (4) a velocity {approx}5-20 km s{sup -1}. The velocity of the chromospheric anemone jets is comparable to the local Alfven speed in the lower solar chromosphere ({approx}10 km s{sup -1}). The histograms of chromospheric anemone jets near the limb and near the disk center show similar averages and shapes of distributions, suggesting that the characteristic behavior of chromospheric anemone jets is independent of whether they are observed on the disk or at the limb. The observed relationship between the velocity and length of chromospheric anemone jets shows that the jets do not follow ballistic motion but are more likely accelerated by some other mechanism. This is consistent with numerical simulations of chromospheric anemone jets.

  19. The mitochondrial genome of Hydra oligactis (Cnidaria, Hydrozoa) sheds new light on animal mtDNA evolution and cnidarian phylogeny

    E-print Network

    Lavrov, Dennis V.

    The mitochondrial genome of Hydra oligactis (Cnidaria, Hydrozoa) sheds new light on animal mt of Hydra oligactis (Cnidaria, Hydrozoa) ­ the first from the class Hydrozoa ­ has been determined that Anthozoa is paraphyletic and that the polyp (rather than a medusa) is the ancestral body type in Cnidaria

  20. Ordered progression of nematogenesis from stem cells through differentiation stages in the tentacle bulb of Clytia hemisphaerica (Hydrozoa, Cnidaria)

    E-print Network

    Gibson, Matt

    bulb of Clytia hemisphaerica (Hydrozoa, Cnidaria) Elsa Denker, Michaël Manuel, Lucas Leclère, Hervé Le, the production of stinging cells (nematocytes) in Cnidaria, can be considered as a model neurogenic process. Most: Cnidaria; Clytia hemisphaerica; Nematocyte; Nematogenesis; Medusa; Tentacle bulb; Minicollagens; Piwi; NOWA

  1. Chromospheric Anemone Jets as Evidence of Ubiquitous Reconnection

    E-print Network

    Kazunari Shibata; Tahei Nakamura; Takuma Matsumoto; Kenichi Otsuji; Takenori J. Okamoto; Naoto Nishizuka; Tomoko Kawate; Hiroko Watanabe; Shin'ichi Nagata; Satoru UeNo; Reizaburo Kitai; Satoshi Nozawa; Saku Tsuneta; Yoshinori Suematsu; Kiyoshi Ichimoto; Toshifumi Shimizu; Yukio Katsukawa; Theodore D. Tarbell; Thomas E. Berger; Bruce W. Lites; Richard A. Shine; Alan M. Title

    2008-10-22

    The heating of the solar chromosphere and corona is a long-standing puzzle in solar physics. Hinode observations show the ubiquitous presence of chromospheric anemone jets outside sunspots in active regions. They are typically 3 to 7 arc seconds = 2000 to 5000 kilometers long and 0.2 to 0.4 arc second = 150 to 300 kilometers wide, and their velocity is 10 to 20 kilometers per second. These small jets have an inverted Y-shape, similar to the shape of x-ray anemone jets in the corona. These features imply that magnetic reconnection similar to that in the corona is occurring at a much smaller spatial scale throughout the chromosphere and suggest that the heating of the solar chromosphere and corona may be related to small-scale ubiquitous reconnection.

  2. Chromospheric anemone jets as evidence of ubiquitous reconnection.

    PubMed

    Shibata, Kazunari; Nakamura, Tahei; Matsumoto, Takuma; Otsuji, Kenichi; Okamoto, Takenori J; Nishizuka, Naoto; Kawate, Tomoko; Watanabe, Hiroko; Nagata, Shin'ichi; Ueno, Satoru; Kitai, Reizaburo; Nozawa, Satoshi; Tsuneta, Saku; Suematsu, Yoshinori; Ichimoto, Kiyoshi; Shimizu, Toshifumi; Katsukawa, Yukio; Tarbell, Theodore D; Berger, Thomas E; Lites, Bruce W; Shine, Richard A; Title, Alan M

    2007-12-01

    The heating of the solar chromosphere and corona is a long-standing puzzle in solar physics. Hinode observations show the ubiquitous presence of chromospheric anemone jets outside sunspots in active regions. They are typically 3 to 7 arc seconds = 2000 to 5000 kilometers long and 0.2 to 0.4 arc second = 150 to 300 kilometers wide, and their velocity is 10 to 20 kilometers per second. These small jets have an inverted Y-shape, similar to the shape of x-ray anemone jets in the corona. These features imply that magnetic reconnection similar to that in the corona is occurring at a much smaller spatial scale throughout the chromosphere and suggest that the heating of the solar chromosphere and corona may be related to small-scale ubiquitous reconnection. PMID:18063790

  3. Mitochondrial genome of the moon jelly Aurelia aurita (Cnidaria, Scyphozoa): A linear DNA molecule

    E-print Network

    Lavrov, Dennis V.

    Mitochondrial genome of the moon jelly Aurelia aurita (Cnidaria, Scyphozoa): A linear DNA molecule sequence of the linear mitochondrial DNA (mt-DNA) molecule of the moon jelly Aurelia aurita (Cnidaria polarities; transcription proceeding toward the ends of the molecule. The determined sequences at the ends

  4. Larval development in Cnidaria: a connection to Bilateria?

    PubMed

    Gröger, H; Schmid, V

    2001-03-01

    Among the basal animal phyla, the Cnidaria display many characteristics similar to the Bilateria (the higher Metazoa). However, the relation of that outgroup phyla to the Bilateria is still equivocal. Additionally to morphological and genetic data, studies on cnidarian embryogenesis are essential to clarify the Cnidaria-Bilateria relationship. We analyzed cellular differentiation during planula larvae development of the jellyfish Podocoryne carnea. Within 24 to 30 h postfertilization, the diploblastic body structure and all cell types found in polyps have already differentiated in the larva. Whereas the differentiating smooth muscles, RFamide-positive nerve cells, or nematocytes (stinging cells) express no axial polarity, a newly discovered tyrosine-tubulin-positive nervous system develops gradually in repetitive patterns from anterior to posterior. These data demonstrate that part of the cnidarian nervous system develops from anterior to posterior in serially repeated patterns. This developmental mechanism seems to follow the bilaterian pattern and would have antedated the Cambrian explosion. PMID:11252050

  5. Interannual variability in abundance of North Sea jellyfish and links to the North Atlantic Oscillation

    Microsoft Academic Search

    Christopher P. Lynam; Stephen J. Hay; Andrew S. Brierley

    2004-01-01

    Pronounced interannual variability in the abundance of medusae of the jellyfish species Aurelia aurita, Cyanea lamarckii, and Cyanea capillata (Phylum Cnidaria, Class Scyphozoa) in the North Sea was evident in data arising from the International Council for the Exploration of the Seas International 0-group Gadoid Surveys between 1971 and 1986. Possible climatic forcing of jellyfish abundance, via the North Atlantic

  6. Lipids of gelatinous antarctic zooplankton: Cnidaria and Ctenophora

    Microsoft Academic Search

    Matthew M. Nelson; Charles F. Phleger; Ben D. Mooney; Peter D. Nichols

    2000-01-01

    Antarctic gelatinous zooplankton, including Cnidaria (Calycopsis borchgrevinki, Diphyes antarctica, Stygiomedusa gigantea, Atolla wyvillei, Dimophyes arctica) and Ctenophora (Beroe cucumis, B. forskalii, Pleurobrachia pileus, Bolinopsis infundibulum) were collected near Elephant Island, South Shetland Islands, during January and February 1997 and 1998. Total lipid was\\u000a low in all zooplankton (0.1–5 mg g?1 wet mass) and included primarily polar lipids (59–96% of total

  7. Structural rearrangements, including parallel inversions, within the chloroplast genome of Anemone and related genera

    Microsoft Academic Search

    Sara B. Hoot; Jeffrey D. Palmer

    1994-01-01

    Chloroplast DNA cleavage sites for 10 restriction enzymes were mapped for 46 species representing all sections of Anemone, four closely related genera (Clematis, Pulsatilla, Hepatica, and Knowltonia), and three more distantly related outgroups (Caltha, Ranunculus, and Adonis). Comparison of the maps revealed that the chloroplast genomes of Anemone and related genera have sustained an unusual number and variety of rearrangements.

  8. Is dimethylsulfoniopropionate (DMSP) produced by the symbionts or the host in an anemone-zooxanthella symbiosis?

    NASA Astrophysics Data System (ADS)

    van Alstyne, K. L.; Dominique, V. J.; Muller-Parker, G.

    2009-03-01

    Many groups of tropical cnidarians including scleractinian corals, octocorals, corallimorphs, and anemones contain the tertiary sulfonium compound dimethylsulfoniopropionate (DMSP). It is not known if the compound is synthesized by the animals, their microalgal symbionts, or derived through their diet. We determined the source of the DMSP in several species of tropical and temperate anemones using three approaches: (1) conducting comparative measurements of DMSP in aposymbiotic and zooxanthellate anemones of three species that harbor zooxanthellae, and similar measurements in one species that can harbor both zooxanthellae and zoochlorellae, (2) manipulating the presence or absence of zooxanthellae by inoculating juvenile aposymbiotic anemones ( Aiptasia pallida) with their symbiont, Symbiodinium bermudense, and (3) manipulating the numbers of S. bermudense by growing aposymbiotic and zooxanthellate A. pallida in the light and the dark. DMSP was present in zooxanthellate anemones in concentrations of 3.4-15 ?mol g-1 fresh mass (FM). In aposymbiotic Aiptasia spp. and Anthopleura elegantissima that lacked large numbers of zooxanthellae, concentrations ranged from being undetectable to 0.43 ?mol g-1 FM. When aposymbiotic A. pallida were inoculated with zooxanthellae, concentrations of DMSP were an average of 4.24 ?mol g-1 FM after 5 weeks; DMSP was undetectable in uninoculated control animals. Aposymbiotic anemones maintained in the light or the dark for 6 weeks contained no DMSP or zooxanthellae. Zooxanthellate anemones in the light contained five times as many zooxanthellae and approximately 7.5 times as much DMSP as zooxanthellate anemones maintained in the dark. Taken together, these data show that the zooxanthellae are the sole source of DMSP in A. pallida. The trends in DMSP concentrations in other species of zooxanthellate anemones suggest that this phenomenon is not limited to A. pallida but may be more generally true for other anemones or even other cnidarians hosting species of Symbiodinium.

  9. @Sea

    NSDL National Science Digital Library

    This site describes the Harbor Branch Oceanographic Institution's at-sea research expeditions and presents both current and archived expeditions from 1999 to the present. Each expedition is described in a feature story with background, definitions, research technology and sampling equipment, maps, photos, daily logs, some videos and virtual tours, researcher profiles, and related links. HBOI scientists have studied maritime history, pharmaceuticals from the sea, sharks, behavior and physiology of marine life, marine sanctuaries and submersible technology.

  10. Evolution of Anemone AR NOAA 10798 and the Related Geo-Effective Flares and CMEs

    E-print Network

    Ayumi Asai; Kazunari Shibata; Takako T. Ishii; Mitsuo Oka; Ryuho Kataoka; Ken'ichi Fujiki; Nat Gopalswamy

    2008-12-11

    We present a detailed examination of the features of the Active Region (AR) NOAA 10798. This AR generated coronal mass ejections (CMEs) that caused a large geomagnetic storm on 24 August 2005 with the minimum Dst index of -216 nT. We examined the evolution of the AR and the features on/near the solar surface and in the interplanetary space. The AR emerged in the middle of a small coronal hole, and formed a {\\it sea anemone} like configuration. H$\\alpha$ filaments were formed in the AR, which have southward axial field. Three M-class flares were generated, and the first two that occurred on 22 August 2005 were followed by Halo-type CMEs. The speeds of the CMEs were fast, and recorded about 1200 and 2400 km s$^{-1}$, respectively. The second CME was especially fast, and caught up and interacted with the first (slower) CME during their travelings toward Earth. These acted synergically to generate an interplanetary disturbance with strong southward magnetic field of about -50 nT, which was followed by the large geomagnetic storm.

  11. Phylogenetics of Trachylina (Cnidaria: Hydrozoa) with new insights on the evolution of some problematical taxa

    E-print Network

    Collins, Allen G.; Bentlage, Bastian; Lindner, Alberto; Lindsay, Dhugal; Haddock, Steven H. D.; Jarms, Gerhard; Norenburg, Jon L.; Jankowski, Thomas; Cartwright, Paulyn

    2008-09-08

    ¨lder. Miglietta M.P., Piraino S., Kubato S. and Schuchert P. (2007) Species in the genus Turritopsis (Cnidaria, Hydrozoa): a molecular evaluation. Journal of Zoological Systematics and Evolutionary Research 45, 11–19. Mu¨hlhardt C. (2003)Molekularbiologie...

  12. Analysis of complete mitochondrial DNA sequences of three members of the Montastraea annularis coral species complex (Cnidaria, Anthozoa, Scleractinia)

    NASA Astrophysics Data System (ADS)

    Fukami, Hironobu; Knowlton, Nancy

    2005-11-01

    Complete mitochondrial nucleotide sequences of two individuals each of Montastraea annularis, Montastraea faveolata, and Montastraea franksi were determined. Gene composition and order differed substantially from the sea anemone Metridium senile, but were identical to that of the phylogenetically distant coral genus Acropora. However, characteristics of the non-coding regions differed between the two scleractinian genera. Among members of the M. annularis complex, only 25 of 16,134 base pair positions were variable. Sixteen of these occurred in one colony of M. franksi, which (together with additional data) indicates the existence of multiple divergent mitochondrial lineages in this species. Overall, rates of evolution for these mitochondrial genomes were extremely slow (0.03 0.04% per million years based on the fossil record of the M. annularis complex). At higher taxonomic levels, patterns of genetic divergence and synonymous/nonsynonymous substitutions suggest non-neutral and unequal rates of evolution between the two lineages to which Montastraea and Acropora belong.

  13. A dinoflagellate symbiont of the coral Oculina diffusa Lamarck (Cnidaria : Anthozoa)

    E-print Network

    Gouldy, Ralph Roland

    1978-01-01

    A DINOFLAGELLATE SYMBIONT OF THE CORAL Oculina diffusa LAMARCK (CNIDARIA : ANTHOZOA) A Thesis by RALPH ROLAND GOULDY Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MASTER... OF SCIENCE August 1978 Major Subject: Biology A DINOFLAGELLATE SYMBIONT OF THE CORAL Oculina diffusa LAMARCK (CNIDARIA: ANTHOZOA) A Thesis By RALPH ROLAND GOULDY Approved as to style and content by: Chairman of Committee Head of Department Membe Me...

  14. RESEARCH ARTICLE Open Access Developing the anemone Aiptasia as a tractable

    E-print Network

    Pringle, John

    RESEARCH ARTICLE Open Access Developing the anemone Aiptasia as a tractable model for cnidarian://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided

  15. CHARACTERIZATION OF MICROSATELLITE LOCI IN THE WIDELY INTRODUCED ESTUARINE ANEMONE NEMATOSTELLA VECTENSIS

    EPA Science Inventory

    We characterized ten polymorphic microsatellite loci from Nematostella vectensis, a burrowing anemone recently introduced to estuaries along the Pacific coast of North America and the southeast coast of England. Preliminary results indicate high variability and significant depar...

  16. Circadian Clocks in the Cnidaria: Environmental Entrainment, Molecular Regulation, and Organismal Outputs

    PubMed Central

    Reitzel, Adam M.; Tarrant, Ann M.; Levy, Oren

    2013-01-01

    The circadian clock is a molecular network that translates predictable environmental signals, such as light levels, into organismal responses, including behavior and physiology. Regular oscillations of the molecular components of the clock enable individuals to anticipate regularly fluctuating environmental conditions. Cnidarians play important roles in benthic and pelagic marine environments and also occupy a key evolutionary position as the likely sister group to the bilaterians. Together, these attributes make members of this phylum attractive as models for testing hypotheses on roles for circadian clocks in regulating behavior, physiology, and reproduction as well as those regarding the deep evolutionary conservation of circadian regulatory pathways in animal evolution. Here, we review and synthesize the field of cnidarian circadian biology by discussing the diverse effects of daily light cycles on cnidarians, summarizing the molecular evidence for the conservation of a bilaterian-like circadian clock in anthozoan cnidarians, and presenting new empirical data supporting the presence of a conserved feed-forward loop in the starlet sea anemone, Nematostella vectensis. Furthermore, we discuss critical gaps in our current knowledge about the cnidarian clock, including the functions directly regulated by the clock and the precise molecular interactions that drive the oscillating gene-expression patterns. We conclude that the field of cnidarian circadian biology is moving rapidly toward linking molecular mechanisms with physiology and behavior. PMID:23620252

  17. Circadian clocks in the cnidaria: environmental entrainment, molecular regulation, and organismal outputs.

    PubMed

    Reitzel, Adam M; Tarrant, Ann M; Levy, Oren

    2013-07-01

    The circadian clock is a molecular network that translates predictable environmental signals, such as light levels, into organismal responses, including behavior and physiology. Regular oscillations of the molecular components of the clock enable individuals to anticipate regularly fluctuating environmental conditions. Cnidarians play important roles in benthic and pelagic marine environments and also occupy a key evolutionary position as the likely sister group to the bilaterians. Together, these attributes make members of this phylum attractive as models for testing hypotheses on roles for circadian clocks in regulating behavior, physiology, and reproduction as well as those regarding the deep evolutionary conservation of circadian regulatory pathways in animal evolution. Here, we review and synthesize the field of cnidarian circadian biology by discussing the diverse effects of daily light cycles on cnidarians, summarizing the molecular evidence for the conservation of a bilaterian-like circadian clock in anthozoan cnidarians, and presenting new empirical data supporting the presence of a conserved feed-forward loop in the starlet sea anemone, Nematostella vectensis. Furthermore, we discuss critical gaps in our current knowledge about the cnidarian clock, including the functions directly regulated by the clock and the precise molecular interactions that drive the oscillating gene-expression patterns. We conclude that the field of cnidarian circadian biology is moving rapidly toward linking molecular mechanisms with physiology and behavior. PMID:23620252

  18. Two new triterpenoid saponins from rhizome of Anemone amurensis.

    PubMed

    Lv, Chong-Ning; Fan, Li; Wang, Jing; Qin, Ru-Lan; Xu, Tan-Ye; Lei, Tian-Li; Lu, Jin-Cai

    2015-02-01

    Two new triterpenoid saponins were isolated from the 70% ethanol extract of the rhizome of Anemone amurensis, they are oleanolic acid 28-O-?-d-glucopyranosyl-(1 ? 3)-?-l-rhamnopyranosyl-(1 ? 4)-?-d-glucopyranosyl-(1 ? 6)-?-d-glucopyranosyl ester (1) and 23,27-dihydroxy oleanolic acid 3-O-?-l-arabinopyranoside (2). The structures of 1 and 2 were elucidated on the basis of chemical and spectral analysis, including 1D and 2D NMR data and HR-ESI-MS. Compounds 1 and 2 were tested for cytotoxicities against three human cancer cell lines (A549, Hep-G2, and MCF-7). Compound 1 showed potent cytotoxicity with IC50 values of 34.76, 41.17, and 28.92 ?M, respectively, while compound 2 with IC50>100 ?M. PMID:25486328

  19. Transmission genetics of allorecognition in Hydractinia symbiolongicarpus (Cnidaria: Hydrozoa)

    SciTech Connect

    Mokady, O.; Buss, L.W. [Yale Univ., New Haven, CT (United States)

    1996-06-01

    Allorecognition is ubiquitous, or nearly so, amongst colonial invertebrates. Despite the prominent role that such phenomena have played both in evolutionary theory and in speculations on the origin of the vertebrate immune system, unambiguous data on the transmission genetics of fusibility (i.e., the ability of two individuals to fuse upon tissue contact) is lacking for any metazoan outside of the phylum Chordata. We have developed lines of the hydroid Hydractinia symbiolongicarpus (Phylum Cnidaria) inbred for fusibility and here report results of breeding experiments establishing that fusibility segregates as expected for a single locus with codominantly expressed alleles, with one shared allele producing a fusible phenotype. Surveys of fusibility in field populations and additional breeding experiments indicate the presence of an extensive allele series. 21 refs., 1 fig., 3 tabs.

  20. Benthic Community Composition and Seabed Characteristics of a Chukchi Sea Pockmark

    NASA Astrophysics Data System (ADS)

    MacDonald, I. R.; Bluhm, B.; Iken, K.; Gagaev, S.; Robinson, S.

    2005-12-01

    Several dozen seafloor features were mapped by Larry Mayer and his colleagues using swath bathymetry during a 2003 cruise with the USCGC HEALY near the eastern edge of the Chukchi Plateau (Chukchi Sea 76.6N, 163.9W). These were sub-circular depressions ranging from approximately 250 to over 1000m in width, with depths of up to 50m below the surrounding seabed, and situated in water depths from 500 to 950m. The origin of these features was undetermined, but one possibility was that they were pockmarks formed as a result of gas or fluid expulsion processes. We report here on benthic sampling undertaken at one of these pockmarks on 18 July 2005, also from USCGC HEALY. This elongated feature had maximum water depth of approximately 940m, was 1200m in maximum width, and was depressed approximately 40m below the surrounding seabed. The ocean in the vicinity of the pockmark was heavily ice-covered, which tightly restricted the ship's mobility during sampling operations. We used an ROV to collect and photograph the benthic epifauna during a 6h transit that crossed from the outside of the pockmark to near the center over a distance of 900m. We used a down-looking digital camera to collect over 800 pictures of the benthos at altitudes of 2 to 3m above the seabed. We also collected three cores with a 25x25cm box corer. Our investigations did not provide any direct evidence for gas or fluid flux through the seabed of this feature. Neither did we see any secondary indications of methane flux such as authigenic carbonates or bacterial mats. The abundance and diversity of benthic epifauna at this station was the highest among 8 stations sampled using similar methods during a 30 day cruise. The ROV observed brittle stars, various types of anemones, shrimps, eel pouts, stalked crinoids, benthic ctenophore (likely new species), burrows and mounts, gooseneck barnacles, mysids. Holothurians (c.f. Peneagone sp.) were the single most abundant group and were often photographed in densities of over 50 individuals per square meter. Preliminary analysis of the box core samples: Polychaetes (e.g. Chaetozone setose, Aricidea sp., Ophelina sp., Progoniada sp., Proclea graffi, Protula globifera), Foraminifera, Nemertini, Coronata (Cnidaria tubes), Sipunculida (Golfingia), Bivalvia, Anthozoa.

  1. New phylogenomic and comparative analyses provide corroborating evidence that Myxozoa is Cnidaria.

    PubMed

    Feng, Jin-Mei; Xiong, Jie; Zhang, Jin-Yong; Yang, Ya-Lin; Yao, Bin; Zhou, Zhi-Gang; Miao, Wei

    2014-12-01

    Myxozoa, a diverse group of morphologically simplified endoparasites, are well known fish parasites causing substantial economic losses in aquaculture. Despite active research, the phylogenetic position of Myxozoa remains ambiguous. After obtaining the genome and transcriptome data of the myxozoan Thelohanellus kitauei, we examined the phylogenetic position of Myxozoa from three different perspectives. First, phylogenomic analyses with the newly sequenced genomic data strongly supported the monophyly of Myxozoa and that Myxozoa is sister to Medusozoa within Cnidaria. Second, we detected two homologs to cnidarian-specific minicollagens in the T. kitauei genome with molecular characteristics similar to cnidarian-specific minicollagens, suggesting that the minicollagen homologs in T. kitauei may have functions similar to those in Cnidaria and that Myxozoa is Cnidaria. Additionally, phylogenetic analyses revealed that the minicollagens in myxozoans and medusozoans have a common ancestor. Third, we detected 11 of the 19 proto-mesodermalgenes in the T. kitauei genome, which were also present in the cnidarian Hydra magnipapillata, indicating Myxozoa is within Cnidaria. Thus, our results robustly support Myxozoa as a derived cnidarian taxon with an affinity to Medusozoa, helping to understand the diversity of the morphology, development and life cycle of Cnidaria and its evolution. PMID:25192780

  2. Influence of host anemone (Stichodactyla haddoni, saville-kent, 1893) locomotion on its resident anemonefish reproduction.

    PubMed

    Balamurugan, R J; Kumar, T T Ajith; Balasubramanian, T

    2013-07-01

    Anemonefish are found commonly in reef habitats and they select only limited anemone species to exist their life. This study describes the movement of anemone, Stichodactyla haddoni and its impact on the reproduction of anemonefishes in captivity. The anemone movement was found to be creeping and in straight-line between successive positions (based on overlay mapping). The distance traveled by the host with (60%) and without substrate (20%) varied significantly (P<0.05) at a random direction. Spawning interval of the resident fish (3-4 days) increased significantly to 8-12 days (P<0.001) because of anemone mobility. Furthermore, host locomotion affected the embryonic development of harbored fish clutches. Percentage of egg maturity (3.5-35.3%) showed an exponential decrease with increase in the distance of substrate from the clutches, from 98 to 100% in the absence of host mobility to 3.5-35% with movement of >60cm. This study concludes that the sedentary habitat would enhance the reproduction value of the harbored fish. Further, in captivity providing with a substrate, supplying regular feed and good light intensity could prevent anemone migration and its implications on the reproductive success of the anemonefish. PMID:23701833

  3. Structural rearrangements, including parallel inversions, within the chloroplast genome of Anemone and related genera.

    PubMed

    Hoot, S B; Palmer, J D

    1994-03-01

    Chloroplast DNA cleavage sites for 10 restriction enzymes were mapped for 46 species representing all sections of Anemone, four closely related genera (Clematis, Pulsatilla, Hepatica, and Knowltonia), and three more distantly related outgroups (Caltha, Ranunculus, and Adonis). Comparison of the maps revealed that the chloroplast genomes of Anemone and related genera have sustained an unusual number and variety of rearrangements. A single inversion of a 42-kb segment was found in the large single-copy region of Adonis aestivalis. Two types of rearrangements were found in the chloroplast genome of Clematis, Anemone, Pulsatilla, Hepatica, and Knowltonia: An approximately 4-kb expansion of the inverted repeat and four inversions within the large single-copy region. These rearrangements support the monophyletic status of these genera, clearly separating them from Caltha, Ranunculus, and Adonis. Two further inversions were found in two Clematis species and three Anemone species. While appearing to support a monophyletic grouping for these taxa, these two inversions conflict with data from both chloroplast restriction sites and morphology and are better interpreted as having occurred twice independently. These are the first two documented cases of homoplastic inversions in chloroplast DNA. Finally, the second intron of the chloroplast rps 12 gene was shown to have been lost in the common ancestor of the same three Anemone species that feature the two homoplastic inversions. PMID:8006994

  4. Oregon Sea Grant Marine Education Program at Hatfield Marine Science Center Animal Adaptations

    E-print Network

    Wright, Dawn Jeannine

    and rocky shores also have to deal with the physical stresses of pounding waves. Because of these harsh are often sessile or attached to rocks to resist wave action and maintain advantageous positions for feeding and reproduction. Some examples of rocky shore creatures are sea stars, barnacles, limpets, urchins, and anemones

  5. Are Hox Genes Ancestrally Involved in Axial Patterning? Evidence from the Hydrozoan Clytia hemisphaerica (Cnidaria)

    PubMed Central

    Chiori, Roxane; Jager, Muriel; Denker, Elsa; Wincker, Patrick; Da Silva, Corinne; Le Guyader, Hervé; Manuel, Michaël; Quéinnec, Eric

    2009-01-01

    Background The early evolution and diversification of Hox-related genes in eumetazoans has been the subject of conflicting hypotheses concerning the evolutionary conservation of their role in axial patterning and the pre-bilaterian origin of the Hox and ParaHox clusters. The diversification of Hox/ParaHox genes clearly predates the origin of bilaterians. However, the existence of a “Hox code” predating the cnidarian-bilaterian ancestor and supporting the deep homology of axes is more controversial. This assumption was mainly based on the interpretation of Hox expression data from the sea anemone, but growing evidence from other cnidarian taxa puts into question this hypothesis. Methodology/Principal Findings Hox, ParaHox and Hox-related genes have been investigated here by phylogenetic analysis and in situ hybridisation in Clytia hemisphaerica, an hydrozoan species with medusa and polyp stages alternating in the life cycle. Our phylogenetic analyses do not support an origin of ParaHox and Hox genes by duplication of an ancestral ProtoHox cluster, and reveal a diversification of the cnidarian HOX9-14 genes into three groups called A, B, C. Among the 7 examined genes, only those belonging to the HOX9-14 and the CDX groups exhibit a restricted expression along the oral-aboral axis during development and in the planula larva, while the others are expressed in very specialised areas at the medusa stage. Conclusions/Significance Cross species comparison reveals a strong variability of gene expression along the oral-aboral axis and during the life cycle among cnidarian lineages. The most parsimonious interpretation is that the Hox code, collinearity and conservative role along the antero-posterior axis are bilaterian innovations. PMID:19156208

  6. Chromospheric anemone jets and magnetic reconnection in partially ionized solar atmosphere

    SciTech Connect

    Singh, K. A. P.; Shibata, K. [Kwasan and Hida Observatories, Kyoto University, Yamashina, Kyoto 607-8471 (Japan); Nishizuka, N. [Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency, 3-1-1, Yoshinodai, Chuo-ku, Sagamihara-shi, Kanagawa (Japan); Isobe, H. [Unit for Synergetic Studies for Space, Kyoto University, Yamashina, Kyoto 607-8471 (Japan)

    2011-11-15

    The solar optical telescope onboard Hinode with temporal resolution of less than 5 s and spatial resolution of 150 km has observed the lower solar atmosphere with an unprecedented detail. This has led to many important findings, one of them is the discovery of chromospheric anemone jets in the solar chromosphere. The chromospheric anemone jets are ubiquitous in solar chromosphere and statistical studies show that the typical length, life time and energy of the chromospheric anemone jets are much smaller than the coronal events (e.g., jets/flares/CMEs). Among various observational parameters, the apparent length and maximum velocity shows good correlation. The velocity of chromospheric anemone jets is comparable to the local Alfven speed in the lower solar chromosphere. Since the discovery of chromospheric anemone jets by Hinode, several evidences of magnetic reconnection in chromospheric anemone jets have been found and these observations are summarized in this paper. These observations clearly suggest that reconnection occurs quite rapidly as well as intermittently in the solar chromosphere. In the solar corona ({lambda}{sub i} > {delta}{sub SP}), anomalous resistivity arises due to various collisionless processes. Previous MHD simulations show that reconnection becomes fast as well as strongly time-dependent due to anomalous resistivity. Such processes would not arise in the solar chromosphere which is fully collisional and partially-ionized. So, it is unclear how the rapid and strongly time-dependent reconnection would occur in the solar chromosphere. It is quite likely that the Hall and ambipolar diffusion are present in the solar chromosphere and they could play an important role in driving such rapid, strongly time-dependent reconnection in the solar chromosphere.

  7. Reaction of the mussel Mytilus galloprovincialis (Bivalvia) to Eugymnanthea inquilina (Cnidaria) and Urastoma cyprinae (Turbellaria) concurrent infestation.

    PubMed

    Mladineo, Ivona; Petri?, Mirela; Hrabar, Jerko; Bo?ina, Ivana; Peharda, Melita

    2012-05-01

    In total 480 individuals of Mytilus galloprovincialis were sampled monthly from October 2009 to September 2010, at the shellfish farm in the Mali Ston Bay, south Adriatic Sea (Croatia) in order to assess the extent of pathology imposed by two parasites, Eugymnanthea inquilina (Cnidaria) and Urastoma cyprinae (Turbellaria). Although a deteriorating impact on host reproduction or condition index was lacking, we evidenced ultrastructural and functional alteration in host cells at the attachment site. Ultrastructural changes included hemocytic encapsulation of the turbellarian and cell desquamation in medusoid infestation. Caspase positive reaction inferred by immunohistochemistry (IHC) was triggered in cases of turbellarian infestation, in contrast with hydroids, suggesting that the former exhibits more complex host-parasite interaction, reflected in the persistent attempts of the parasite to survive bivalve reaction. We have evidenced that both organisms trigger specific host reaction that although not costly in terms of host reproductive cycle or growth, results in mild tissue destruction and hemocyte activation. A lower degree of tissue reaction was observed in cases of hydroid infestation, compared to turbellarian. PMID:22426355

  8. Morphology and morphodynamics of the stenotele nematocyst of Hydra attenuata Pall. (Hydrozoa, Cnidaria)

    Microsoft Academic Search

    Pierre Tardent; Thomas Holstein

    1982-01-01

    This light- and electron-microscopic study has investigated the structure, the morphodynamics of discharge, and the impact of the stenotele cyst of Hydra attenuata (Hydrozoa, Cnidaria) on the prey's integument. The triggered capsule, which is ejected from the cell, discharges its tubular content (shaft, stylets and tubule) by a process of evagination. In doing so the three joined stylets punch a

  9. Carbon metabolism and strobilation in Cassiopea andromedea (Cnidaria: Scyphozoa): Significance of endosymbiotic dinoflagellates

    Microsoft Academic Search

    D. K. Hofmann; B. P. Kremer

    1981-01-01

    Scyphopolyps and scyphomedusae of Cassiopea andromeda Forskål (Cnidaria, Scyphozoa) containing dinoflagellate endosymbionts (zooxanthellae) were investigated for rates and pathways of carbon fixation. Photosynthesis by the algae, accounting for 80 and 15 µmol C h-1 on a dry weight basis in medusae and polyps, respectively, by far exceeds dark incorporation of inorganic carbon by the intact association. Photosynthetic carbon fixation is

  10. Bud formation and metamorphosis in Cassiopea andromeda (Cnidaria: Scyphozoa): A developmental and ultrastructural study

    Microsoft Academic Search

    D. K. Hofmann; T. G. Honegger

    1990-01-01

    Asexual reproduction by formation of swimming buds which metamorphose directly into polyps plays a most important role in the propagation ofCassiopea andromeda (Cnidaria: Scyphozoa). (C. andromeda polyps, originally supplied by the Löbbecke Museum and Aquarium Düsseldorf, FRG, were cultured in our laboratories.) We have defined five budding stages and investigated epithelial recruitment and dynamics during bud formation using intracellular vital

  11. Behind anemone lines: factors affecting division of labour in the social cnidarian Anthopleura elegantissima

    E-print Network

    Grosberg, Rick

    Behind anemone lines: factors affecting division of labour in the social cnidarian Anthopleura and (2) larger `reproductive' polyps that are more likely to carry ripe gonads. Here we show immediately adjacent to scouts); `free-edge' polyps; and in the centres of clones, large `reproductives

  12. !Yes~igation of the Matina Svstem and Reproduction in The Pasque Flower (Anemone patens)

    Microsoft Academic Search

    Anne Mein

    Klein Anne The buttercup family (Ranunculaceae) exhlbits a lot of variation in pollination methods and breeding strategies, where outcrossing (xenogamy) is typical, but self-fertilization (autogamy) has been observed. This study is an investigation of the breeding system and the pollination biology of Anemone patens, which exhibits both xenogamy and autogamy. Treatment groups were set up and analyzed to look at

  13. Inferring distributions of chirodropid box-jellyfishes (Cnidaria: Cubozoa) in geographic and ecological space using ecological niche modeling

    E-print Network

    Bentlage, Bastian; Peterson, A. Townsend; Cartwright, Paulyn

    2009-05-29

    the potential distributions of these species as well. We explored the utility of ENM to investigate potential distributions of chirodropid box-jellyfishes (Cnidaria: Cubozoa), a group of highly toxic invertebrates whose biogeography is poorly understood. We were...

  14. NUMERICAL SIMULATIONS OF CHROMOSPHERIC ANEMONE JETS ASSOCIATED WITH MOVING MAGNETIC FEATURES

    SciTech Connect

    Yang, Liping; He, Jiansen; Tu, Chuanyi; Zhang, Lei [School of Earth and Space Sciences, Peking University, 100871 Beijing (China); Peter, Hardi [Max Planck Institute for Solar System Research, D-37191 Katlenburg-Lindau (Germany); Feng, Xueshang [SIGMA Weather Group, State Key Laboratory for Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, 100871 Beijing (China); Zhang, Shaohua, E-mail: jshept@gmail.com [Institute of Geology and Geophysics, Chinese Academy of Sciences, 100871 Beijing (China)

    2013-11-01

    Observations with the space-based solar observatory Hinode show that small-scale magnetic structures in the photosphere are found to be associated with a particular class of jets of plasma in the chromosphere called anemone jets. The goal of our study is to conduct a numerical experiment of such chromospheric anemone jets related to the moving magnetic features (MMFs). We construct a 2.5 dimensional numerical MHD model to describe the process of magnetic reconnection between the MMFs and the pre-existing ambient magnetic field, which is driven by the horizontal motion of the magnetic structure in the photosphere. We include thermal conduction parallel to the magnetic field and optically thin radiative losses in the corona to account for a self-consistent description of the evaporation process during the heating of the plasma due to the reconnection process. The motion of the MMFs leads to the expected jet and our numerical results can reproduce many observed characteristics of chromospheric anemone jets, topologically and quantitatively. As a result of the tearing instability, plasmoids are generated in the reconnection process that are consistent with the observed bright moving blobs in the anemone jets. An increase in the thermal pressure at the base of the jet is also driven by the reconnection, which induces a train of slow-mode shocks propagating upward. These shocks are a secondary effect, and only modulate the outflow of the anemone jet. The jet itself is driven by the energy input due to the reconnection of the MMFs and the ambient magnetic field.

  15. Neuronal cell death during metamorphosis of Hydractina echinata (Cnidaria, Hydrozoa).

    PubMed

    Seipp, Stefanie; Schmich, Jürgen; Will, Britta; Schetter, Eva; Plickert, Günter; Leitz, Thomas

    2010-12-01

    In planula larvae of the invertebrate Hydractinia echinata (Cnidaria, Hydrozoa), peptides of the GLWamide and the RFamide families are expressed in distinct subpopulations of neurons, distributed in a typical spatial pattern through the larval body. However, in the adult polyp GLWamide or RFamide-expressing cells are located at body parts that do not correspond to the prior larval regions. Since we had shown previously that during metamorphosis a large number of cells are removed by programmed cell death (PCD), we aimed to analyze whether cells of the neuropeptide-expressing larval nerve net are among those sacrificed. By immunohistochemical staining and in situ hybridization, we labeled GLWamide- and RFamide-expressing cells. Double staining of neuropeptides and degraded DNA (TUNEL analysis) identified some neurosensory cells as being apoptotic. Derangement of the cytoplasm and rapid destruction of neuropeptide precursor RNA indicated complete death of these particular sensory cells in the course of metamorphosis. Additionally, a small group of RFamide-positive sensory cells in the developing mouth region of the primary polyp could be shown to emerge by proliferation. Our results support the idea that during metamorphosis, specific parts of the larval neuronal network are subject to neurodegeneration and therefore not used for construction of the adult nerve net. Most neuronal cells of the primary polyp arise by de novo differentiation of stem cells commited to neural differentiation in embryogenesis. At least some nerve cells derive from proliferation of progenitor cells. Clarification of how the nerve net of these basal eumetazoans degenerates may add information to the understanding of neurodegeneration by apoptosis as a whole in the animal kingdom. PMID:21104287

  16. Development of the rhopalial nervous system in Aurelia sp.1 (Cnidaria, Scyphozoa)

    Microsoft Academic Search

    Nagayasu Nakanishi; Volker Hartenstein; David K. Jacobs

    2009-01-01

    We examined the development of the nervous system in the rhopalium, a medusa-specific sensory structure, in Aurelia sp.1 (Cnidaria, Scyphozoa) using confocal microscopy. The rhopalial nervous system appears primarily ectodermal and contains\\u000a neurons immunoreactive to antibodies against tyrosinated tubulin, taurine, GLWamide, and FMRFamide. The rhopalial nervous\\u000a system develops in an ordered manner: the presumptive gravity-sensing organ, consisting of the lithocyst

  17. Agent of whirling disease meets orphan worm: phylogenomic analyses firmly place Myxozoa in Cnidaria.

    PubMed

    Nesnidal, Maximilian P; Helmkampf, Martin; Bruchhaus, Iris; El-Matbouli, Mansour; Hausdorf, Bernhard

    2013-01-01

    Myxozoa are microscopic obligate endoparasites with complex live cycles. Representatives are Myxobolus cerebralis, the causative agent of whirling disease in salmonids, and the enigmatic "orphan worm" Buddenbrockia plumatellae parasitizing in Bryozoa. Originally, Myxozoa were classified as protists, but later several metazoan characteristics were reported. However, their phylogenetic relationships remained doubtful. Some molecular phylogenetic analyses placed them as sister group to or even within Bilateria, whereas the possession of polar capsules that are similar to nematocysts of Cnidaria and of minicollagen genes suggest a close relationship between Myxozoa and Cnidaria. EST data of Buddenbrockia also indicated a cnidarian origin of Myxozoa, but were not sufficient to reject a closer relationship to bilaterians. Phylogenomic analyses of new genomic sequences of Myxobolus cerebralis firmly place Myxozoa as sister group to Medusozoa within Cnidaria. Based on the new dataset, the alternative hypothesis that Myxozoa form a clade with Bilateria can be rejected using topology tests. Sensitivity analyses indicate that this result is not affected by long branch attraction artifacts or compositional bias. PMID:23382916

  18. Agent of Whirling Disease Meets Orphan Worm: Phylogenomic Analyses Firmly Place Myxozoa in Cnidaria

    PubMed Central

    Nesnidal, Maximilian P.; Helmkampf, Martin; Bruchhaus, Iris; El-Matbouli, Mansour; Hausdorf, Bernhard

    2013-01-01

    Myxozoa are microscopic obligate endoparasites with complex live cycles. Representatives are Myxobolus cerebralis, the causative agent of whirling disease in salmonids, and the enigmatic “orphan worm” Buddenbrockia plumatellae parasitizing in Bryozoa. Originally, Myxozoa were classified as protists, but later several metazoan characteristics were reported. However, their phylogenetic relationships remained doubtful. Some molecular phylogenetic analyses placed them as sister group to or even within Bilateria, whereas the possession of polar capsules that are similar to nematocysts of Cnidaria and of minicollagen genes suggest a close relationship between Myxozoa and Cnidaria. EST data of Buddenbrockia also indicated a cnidarian origin of Myxozoa, but were not sufficient to reject a closer relationship to bilaterians. Phylogenomic analyses of new genomic sequences of Myxobolus cerebralis firmly place Myxozoa as sister group to Medusozoa within Cnidaria. Based on the new dataset, the alternative hypothesis that Myxozoa form a clade with Bilateria can be rejected using topology tests. Sensitivity analyses indicate that this result is not affected by long branch attraction artifacts or compositional bias. PMID:23382916

  19. The Antitumor Effects of Triterpenoid Saponins from the Anemone flaccida and the Underlying Mechanism

    PubMed Central

    Han, Lin-Tao; Fang, Ying; Li, Ming-Ming; Yang, Hong-Bing; Huang, Fang

    2013-01-01

    Anemone flaccida Fr. Schmidt, a family of ancient hopanoids, have been used as traditional Asian herbs for the treatments of inflammation and convulsant diseases. Previous study on HeLa cells suggested that triterpenoid saponins from Anemone flaccida Fr. Schmidt may have potential antitumor effect due to their apoptotic activities. Here, we confirmed the apoptotic activities of the following five triterpenoid saponins: glycoside St-I4a (1), glycoside St-J (2), anhuienoside E (3), hedera saponin B (4), and flaccidoside II (5) on human BEL-7402 and HepG2 hepatoma cell lines, as well as the model of HeLa cells treated with lipopolysaccharide (LPS). We found that COX-2/PGE2 signaling pathway, which plays key roles in the development of cancer, is involved in the antitumor activities of these saponins. These data provide the evidence that triterpenoid saponins can induce apoptosis via COX-2/PGE2 pathway, implying a preventive role of saponins from Anemone flaccida in tumor. PMID:24191167

  20. The effects of sexual and asexual reproduction on geographic variation in the sea anemone Actinia tenebrosa

    Microsoft Academic Search

    D. J. Ayre

    1984-01-01

    Allelic and genotypic frequencies were determined for samples from 35 widely distributed Australasian colonies of Actinia tenebrosa and 2 South African colonies of A. equina. These data provided no evidence of gene flow between Australisian and South African Actinia colonies and indicated that there may be some restriction of gene flow between widely separated Australasian colonies.

  1. Sexual reproduction of two intertidal sea anemones (Coelenteria: Actiniaria) in Malaysia

    E-print Network

    Fautin, Daphne G.

    1982-01-01

    Sexual reproduction in the actinians *Anthopleura handi* Dunn and *Haliplanella luciae* (Verrill) was studied through one year at Jeram, on the Malacca Straits. No evidence could be marshalled to support periodicity in gametogenesis of either...

  2. From Sea Anemone to Homo sapiens: The Evolution of the p53 Family of Genes

    SciTech Connect

    Arnold Levine

    2009-09-14

    Levine, a leading authority on the molecular basis of cancer, gives a lecture on how the genes for p53 (genes that prevent cancer and preserve life) and related proteins have survived through a billion years of evolution.

  3. Development and epithelial organisation of muscle cells in the sea anemone Nematostella vectensis

    PubMed Central

    2014-01-01

    Introduction Nematostella vectensis, a member of the cnidarian class Anthozoa, has been established as a promising model system in developmental biology, but while information about the genetic regulation of embryonic development is rapidly increasing, little is known about the cellular organization of the various cell types in the adult. Here, we studied the anatomy and development of the muscular system of N. vectensis to obtain further insights into the evolution of muscle cells. Results The muscular system of N. vectensis is comprised of five distinct muscle groups, which are differentiated into a tentacle and a body column system. Both systems house longitudinal as well as circular portions. With the exception of the ectodermal tentacle longitudinal muscle, all muscle groups are of endodermal origin. The shape and epithelial organization of muscle cells vary considerably between different muscle groups. Ring muscle cells are formed as epitheliomuscular cells in which the myofilaments are housed in the basal part of the cell, while the apical part is connected to neighboring cells by apical cell-cell junctions. In the longitudinal muscles of the column, the muscular part at the basal side is connected to the apical part by a long and narrow cytoplasmic bridge. The organization of these cells, however, remains epitheliomuscular. A third type of muscle cell is represented in the longitudinal muscle of the tentacle. Using transgenic animals we show that the apical cell-cell junctions are lost during differentiation, resulting in a detachment of the muscle cells to a basiepithelial position. These muscle cells are still located within the epithelium and outside of the basal matrix, therefore constituting basiepithelial myocytes. We demonstrate that all muscle cells, including the longitudinal basiepithelial muscle cells of the tentacle, initially differentiate from regular epithelial cells before they alter their epithelial organisation. Conclusions A wide range of different muscle cell morphologies can already be found in a single animal. This suggests how a transition from an epithelially organized muscle system to a mesenchymal could have occurred. Our study on N. vectensis provides new insights into the organisation of a muscle system in a non-bilaterian organism. PMID:25009575

  4. OXYGEN RADICAL PRODUCTION IN THE SEA ANEMONE ANTHOPLEURA ELEGANTISSIMA AND ITS ENDOSYMBIOTIC ALGAE

    Microsoft Academic Search

    JAMES A. DYKENS; J. MALCOLM SHICK; CRAIG BENOIT; GARRY R. BUETTNER; GARY W. WINSTON

    1992-01-01

    Summary Host animals in algal-invertebrate endosymbiotic associations are exposed to photosynthetically generated hyperoxia while in sunlight, conditions conducive to photodynamic excitations and production of cytotoxic oxygen-derived radicals such as the superoxide anion (O 2 T ) and the hydroxyl radical ('OH). All previous evidence of oxyradical production in symbiotic associations has been circumstan- tial. We here present direct evidence, from

  5. Regulation of spirocyst discharge in the model sea anemone, Nematostella vectensis

    Microsoft Academic Search

    Sherry L. Krayesky; Janna L. Mahoney; Katherine M. Kinler; Stacey Peltier; Warnesha Calais; Kate Allaire; Glen M. Watson

    2010-01-01

    Test probes were touched to tentacles to investigate whether discharge of spirocysts likely is regulated by hair bundle mechanoreceptors.\\u000a Significantly more spirocysts discharge onto test probes in the presence of vibrations at 11–15 Hz as compared to 0 Hz. Adding\\u000a N-acetylneuraminic acid, NANA, shifts maximal discharge of spirocysts upwards to 36–40 Hz, and possibly to 21–25 Hz. In contrast,\\u000a NANA shifts maximal discharge of

  6. Properties of a toxin from the sea anemone Stoichacis helianthus, including specific binding to sphingomyelin.

    PubMed Central

    Bernheimer, A W; Avigad, L S

    1976-01-01

    Stoichactis helianthus toxin, a protein derived presumably from the nematocysts, was purified to homogeneity. It has a molecular weight of about 16,000, an isoelectric pH of 9.8, and it contains approximately 3.7% carbohydrate. It is powerfully hemolytic for erythrocytes derived from a variety of animal species, those of the cat being the most sensitive and those of the guinea pig the most resistant. The toxin is lytic also for rabbit blood platelets, and it destroys cultured fibroblasts but is inactive for several kinds of bacterial protoplasts and spheroplasts. The hemolytic activity is specifically inhibited by sphingomyelin, and it is proposed that this phospholipid is the constituent of the membrane which functions as receptor for the toxin. Supporting evidence includes the findings that enzymes known to destroy sphingomyelin (a) prevent erythrocyte membranes from inhibiting hemolysis, and (b) render erythrocytes resistant to lysis by the toxin. The mechanism underlying hemolysis may involve translocation of membrane sphingomyelin by virtue of a specific affinity of the coelenterate protein for this phospholipid. PMID:1757

  7. Functional Characterisation of a TRPM2 orthologue from the sea anemone Nematostella vectensis in human cells

    PubMed Central

    Kühn, Frank J. P.; Kühn, Cornelia; Lückhoff, Andreas

    2015-01-01

    The human non-selective cation channel TRPM2 represents a mediator of apoptosis triggered by oxidative stress. The principal agonist ADP-ribose binds to the cytosolic domain of TRPM2, which is homologous to the human ADP-ribose pyrophosphatase NUDT9. To further elucidate the structure-function relationship of this channel, we characterised a TRPM2 orthologue from the cnidarian Nematostella vectensis, after its expression in a human cell line. This far distant relative shows only 31% total sequence similarity to hTRPM2, while its C-terminal domain has a greater resemblance to the NUDT9 enzyme. Current through nvTRPM2 was induced by ADPR, with a more pronounced sensitivity and faster kinetics than in hTRPM2. In contrast to hTRPM2, there was no response to H2O2 and hardly any modulatory effect by intracellular Ca2+. The deletion of a stretch of 15 residues from the NUDT9 domain of nvTRPM2, which is absent in hTRPM2, did not change the response to ADPR but enabled activation of the channel by H2O2 and increased the effects of intracellular Ca2+. These findings shed new light on the evolution of TRPM2 and establish nvTRPM2 as a promising tool to decipher its complex gating mechanisms. PMID:25620041

  8. Die Nesselkapseln der Cnidaria, mit besonderer Berücksichtigung der Hydroida

    Microsoft Academic Search

    Bernhard Werner

    1965-01-01

    Long-term investigations on the ecology, morphology and systematics of hydroids, both of the North Sea and the Mediterranean, confirmed the results of earlier authors that most species differ in number and quality of their nematocysts. The classification byWeill (1934) facilitates a satisfactory diagnosis of the different types of nematocysts present in marine Cnidarians; it is based on morphological characteristics of

  9. Active Nematocyst Isolation Via Nudibranchs

    Microsoft Academic Search

    Ami Schlesinger; Esti Kramarsky-Winter; Yossi Loya

    2009-01-01

    Cnidarian venoms are potentially valuable tools for biomedical research and drug development. They are contained within nematocysts,\\u000a the stinging organelles of cnidarians. Several methods exist for the isolation of nematocysts from cnidarian tissues; most\\u000a are tedious and target nematocysts from specific tissues. We have discovered that the isolated active nematocyst complement\\u000a (cnidome) of several sea anemone (Cnidaria: Anthozoa) species is

  10. MULTIPLE PLASMA EJECTIONS AND INTERMITTENT NATURE OF MAGNETIC RECONNECTION IN SOLAR CHROMOSPHERIC ANEMONE JETS

    SciTech Connect

    Singh, K. A. P.; Nishida, K.; Shibata, K. [Kwasan and Hida Observatories, Graduate School of Science, Kyoto University, Yamashina, Kyoto 607-8471 (Japan); Isobe, H. [Unit of Synergetic Study for Space, Kyoto University, Yamashina, Kyoto 607-8471 (Japan); Nishizuka, N., E-mail: singh@kwasan.kyoto-u.ac.jp, E-mail: nishida@kwasan.kyoto-u.ac.jp, E-mail: shibata@kwasan.kyoto-u.ac.jp, E-mail: isobe@kwasan.kyoto-u.ac.jp, E-mail: nishizuka.naoto@jaxa.jp [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara-shi, Kanagawa 229-8510 (Japan)

    2012-11-01

    The recent discovery of chromospheric anemone jets with the Solar Optical Telescope (SOT) on board Hinode has shown an indirect evidence of magnetic reconnection in the solar chromosphere. However, the basic nature of magnetic reconnection in chromosphere is still unclear. We studied nine chromospheric anemone jets from SOT/Hinode using Ca II H filtergrams, and we found multiple bright, plasma ejections along the jets. In most cases, the major intensity enhancements (larger than 30% relative to the background intensity) of the loop correspond to the timing of the plasma ejections. The typical lifetime and size of the plasma ejecta are about 20-60 s and 0.3-1.5 Mm, respectively. The height-time plot of jet shows many sub-structures (or individual jets) and the typical lifetime of the individual jet is about one to five minutes. Before the onset of the jet activity, a loop appears in Ca II H and gradually increases in size, and after few minutes several jets are launched from the loop. Once the jet activity starts and several individual jets are launched, the loop starts shrinking with a speed of {approx}4 km s{sup -1}. In some events, a downward moving blob with a speed of {approx}35 km s{sup -1} was observed, associated with the upward moving plasma along one of the legs of the loop hosting the jets. The upward moving plasma gradually developed into jets. Multiple plasma ejections in chromospheric anemone jet show the strongly time-dependent as well as intermittent nature of magnetic reconnection in the solar chromosphere.

  11. Correction: Phylogenetic placement of the enigmatic parasite, Polypodium hydriforme, within the Phylum Cnidaria

    E-print Network

    Evans, Nathaniel M.; Lindner, Alberto; Raikova, Ekaterina V.; Collins, Allen G.; Cartwright, Paulyn

    2009-07-15

    that Polypodium hydriforme is a cnidarian (Figure ThreeB and Additional file ThreeB [1]) this placement should be viewed as tentative due to low bootstrap sup- port (83% supporting a monophyletic Cnidaria that includes Polypodium) (Additional file ThreeB [1..., distribution, and reproduction in any medium, provided the original work is properly cited.Page 1 of 2 (page number not for citation purposes) dataset including the Polypodium 18S and Obelia 28S as separate samples. The topologies with regards to the 28S r...

  12. Modeling the Structure of the Sea Anemone, Stomphia Coccinea and the Sea Star, Dermasterias Imbricata Using Implicit Surfaces

    E-print Network

    Wyvill, Brian

    Imbricata Using Implicit Surfaces Xikun Liang xkliang@cpsc.ucalgary.ca Mai Ali Nur mnur@cpsc.ucalgary.ca Brian Wyvill blob@cpsc.ucalgary.ca Department of Computer Science University of Calgary 2500 University

  13. Global diversity and review of Siphonophorae (Cnidaria: Hydrozoa).

    PubMed

    Mapstone, Gillian M

    2014-01-01

    In this review the history of discovery of siphonophores, from the first formal description by Carl Linnaeus in 1785 to the present, is summarized, and species richness together with a summary of world-wide distribution of this pelagic group within the clade Hydrozoa discussed. Siphonophores exhibit three basic body plans which are briefly explained and figured, whilst other atypical body plans are also noted. Currently, 175 valid siphonophore species are recognized in the latest WoRMS world list, including 16 families and 65 genera. Much new information since the last review in 1987 is revealed from the first molecular analysis of the group, enabling identification of some new morphological characters diagnostic for physonect siphonophores. Ten types of nematocysts (stinging cells) are identified in siphonophores, more than in any other cnidarian; these are incorporated into batteries in the side branches of the tentacles in most species (here termed tentilla), and tentilla are reviewed in the last section of this paper. Their discharge mechanisms are explained and also how the tentilla of several physonect siphonophores are modified into lures. Of particular interest is the recent discovery of a previously unknown red fluorescent lure in the tentilla of the deep sea physonect Erenna, the first described example of emission of red light by an invertebrate to attract prey. PMID:24516560

  14. Global Diversity and Review of Siphonophorae (Cnidaria: Hydrozoa)

    PubMed Central

    Mapstone, Gillian M.

    2014-01-01

    In this review the history of discovery of siphonophores, from the first formal description by Carl Linnaeus in 1785 to the present, is summarized, and species richness together with a summary of world-wide distribution of this pelagic group within the clade Hydrozoa discussed. Siphonophores exhibit three basic body plans which are briefly explained and figured, whilst other atypical body plans are also noted. Currently, 175 valid siphonophore species are recognized in the latest WoRMS world list, including 16 families and 65 genera. Much new information since the last review in 1987 is revealed from the first molecular analysis of the group, enabling identification of some new morphological characters diagnostic for physonect siphonophores. Ten types of nematocysts (stinging cells) are identified in siphonophores, more than in any other cnidarian; these are incorporated into batteries in the side branches of the tentacles in most species (here termed tentilla), and tentilla are reviewed in the last section of this paper. Their discharge mechanisms are explained and also how the tentilla of several physonect siphonophores are modified into lures. Of particular interest is the recent discovery of a previously unknown red fluorescent lure in the tentilla of the deep sea physonect Erenna, the first described example of emission of red light by an invertebrate to attract prey. PMID:24516560

  15. New records of Primnoidae (Cnidaria: Octocorallia) in Brazilian deep waters

    NASA Astrophysics Data System (ADS)

    Arantes, Renata C. M.; Loiola, Livia L.

    2014-01-01

    The knowledge of octocorals occurring in Brazilian deep waters is still lacking, with only a few studies conducted so far, most of which focused on large-scale marine habitats characterization. Primnoidae are common and characteristic of seamounts and deepwater coral banks, often providing habitat for other marine species. Although primnoids occur in all ocean basins, only Primnoella and Plumarella species were recorded along the Brazilian coast before this study. Primnoid specimens were obtained through dredging and remotely operated vehicles (ROV) sampling, collected by research projects conducted off the Brazilian coast, between 15 and 34°S. Taxonomic assessment resulted in 5 new records of Primnoidae genera in Brazil: Calyptrophora, Candidella, Dasystenella, Narella and Thouarella. The occurrences of Narella-off Salvador and Vitória, and in Campos Basin (935-1700 m), and Calyptrophora-in Campos Basin (1059-1152 m), are herein reported for the first time in the South Atlantic. Calyptrophora microdentata was previously known in Lesser Antilles, New England and Corner Rise Seamounts, between 686 and 2310 m. Candidella imbricata geographical distribution includes Western and Eastern Atlantic (514-2063 m and 815-2139 m, respectively), being registered herein in Campos Basin, between 1059 and 1605 m. Dasystenella acanthina collected off Rio Grande do Sul state (810 m) and occurs also off Argentina and Southern Ocean, between 150 and 5087 m. Plumarella diadema, which type locality is off São Sebastião, Brazil, has its geographical range extended northwards, occurring in Campos Basin (650 m). Thouarella koellikeri previously known for Patagonia and Antartic Peninsula, is registered for the off Brazil for the first time, in Campos Basin and off São Sebastião (609-659 m). There is a lot of work yet to be done in terms of taxonomic knowledge of Brazilian deep-sea octocorals. Research projects focusing on the investigations, including ROV sampling, of other geographical regions and depth ranges along Brazilian coast will certainly reveal other new octocorals occurrences and species.

  16. Growth of the Antarctic octocoral Primnoella scotiae and predation by the anemone Dactylanthus antarcticus

    NASA Astrophysics Data System (ADS)

    Peck, Lloyd S.; Brockington, Simon

    2013-08-01

    Growth rates in Antarctic marine ectotherms have been demonstrated to be slowed by two to five times compared to shallow-water temperate species, with no previous reports for octocorals. Here growth rates were estimated in the single axis, non-branching Antarctic octocoral Primnoella scotiae using repeated in situ length measures covering both summer and winter periods, for tagged colonies from three sites at Signy Island over a two year period. Mean rates of length increase at the different sites ranged from 0.96 mm yr-1 to 55.3 mm yr-1. The fastest individual colony growth rate at any site ranged from 2.55 mm yr-1 to 175.6 mm yr-1. The mean of the fastest growth rates across all sites was 33.0 mm yr-1±14.7 (s.e.). Growth was significantly different between sites, and also between seasons and years. The mean overall increase in diameter of the average sized colony in the study (222.5 mm in axis length) was 0.053 mm yr-1. This is the slowest reported growth rate of any octocoral to date, and is five times slower than growth in most cold water octocorals. During the study it was noted that colonies were being attacked and consumed by the anemone Dactylanthus antarcticus. At one of the sites studied, between 5% and 8% of colonies surveyed were attacked each month. Anemone dispersal was via whole body inflation and drifting to new prey colonies that were attached to using tentacle-like column protuberances.

  17. Phylogenetic placement of the enigmatic parasite, Polypodium hydriforme, within the Phylum Cnidaria

    PubMed Central

    2008-01-01

    Background Polypodium hydriforme is a parasite with an unusual life cycle and peculiar morphology, both of which have made its systematic position uncertain. Polypodium has traditionally been considered a cnidarian because it possesses nematocysts, the stinging structures characteristic of this phylum. However, recent molecular phylogenetic studies using 18S rDNA sequence data have challenged this interpretation, and have shown that Polypodium is a close relative to myxozoans and together they share a closer affinity to bilaterians than cnidarians. Due to the variable rates of 18S rDNA sequences, these results have been suggested to be an artifact of long-branch attraction (LBA). A recent study, using multiple protein coding markers, shows that the myxozoan Buddenbrockia, is nested within cnidarians. Polypodium was not included in this study. To further investigate the phylogenetic placement of Polypodium, we have performed phylogenetic analyses of metazoans with 18S and partial 28S rDNA sequences in a large dataset that includes Polypodium and a comprehensive sampling of cnidarian taxa. Results Analyses of a combined dataset of 18S and partial 28S sequences, and partial 28S alone, support the placement of Polypodium within Cnidaria. Removal of the long-branched myxozoans from the 18S dataset also results in Polypodium being nested within Cnidaria. These results suggest that previous reports showing that Polypodium and Myxozoa form a sister group to Bilateria were an artifact of long-branch attraction. Conclusion By including 28S rDNA sequences and a comprehensive sampling of cnidarian taxa, we demonstrate that previously conflicting hypotheses concerning the phylogenetic placement of Polypodium can be reconciled. Specifically, the data presented provide evidence that Polypodium is indeed a cnidarian and is either the sister taxon to Hydrozoa, or part of the hydrozoan clade, Leptothecata. The former hypothesis is consistent with the traditional view that Polypodium should be placed in its own cnidarian class, Polypodiozoa. PMID:18471296

  18. Internal and external relationships of the Cnidaria: implications of primary and predicted secondary structure of the 5'-end of the 23S-like rDNA.

    PubMed Central

    Odorico, D M; Miller, D J

    1997-01-01

    Since both internal (class-level) and external relationships of the Cnidaria remain unclear on the basis of analyses of 18S and (partial) 16S rDNA sequence data, we examined the informativeness of the 5'-end of the 23S-like rDNA. Here we describe analyses of both primary and predicted secondary structure data for this region from the ctenophore Bolinopsis sp., the placozoan Trichoplax adhaerens, the sponge Hymeniacidon heliophila, and representatives of all four cnidarian classes. Primary sequence analyses clearly resolved the Cnidaria from other lower Metazoa, supported sister group relationships between the Scyphozoa and Cubozoa and between the Ctenophora and the Placozoa, and confirmed the basal status of the Anthozoa within the Cnidaria. Additionally, in the ctenophore, placozoan and sponge, non-canonical base pairing is required to maintain the secondary structure of the B12 region, whereas amongst the Cnidaria this is not the case. Although the phylogenetic significance of this molecular character is unclear, our analyses do not support the close relationship between Cnidaria and Placozoa suggested by previous studies. PMID:9061962

  19. Shallow-water zoantharians (Cnidaria, Hexacorallia) from the Central Indo-Pacific.

    PubMed

    Reimer, James D; Poliseno, Angelo; Hoeksema, Bert W

    2014-01-01

    Despite the Central Indo-Pacific (CIP) and the Indonesian Archipelago being a well-known region of coral reef biodiversity, particularly in the 'Coral Triangle', little published information is available on its zoantharians (Cnidaria: Hexacorallia: Zoantharia). In order to provide a basis for future research on the Indo-Pacific zoantharian fauna and facilitate comparisons between more well-studied regions such as Japan and the Great Barrier Reef, this report deals with CIP zoantharian specimens in the Naturalis collection in Leiden, the Netherlands; 106 specimens were placed into 24 morpho-species and were supplemented with 88 in situ photographic records from Indonesia, the Philippines, and Papua New Guinea. At least nine morpho-species are likely to be undescribed species, indicating that the region needs more research in order to properly understand zoantharian diversity within the CIP. The Naturalis' zoantharian specimens are listed by species, as well as all relevant collection information, and in situ images are provided to aid in future studies on zoantharians in the CIP. PMID:25349499

  20. Gross and microscopic morphology of lesions in Cnidaria from Palmyra Atoll, Central Pacific.

    PubMed

    Williams, Gareth J; Work, Thierry M; Aeby, Greta S; Knapp, Ingrid S; Davy, Simon K

    2011-02-01

    We conducted gross and microscopic characterizations of lesions in Cnidaria from Palmyra Atoll, Central Pacific. We found growth anomalies (GA) to be the most commonly encountered lesion. Cases of discoloration and tissue loss were rare. GAs had a focal or multi-focal distribution and were predominantly nodular, exophytic, and umbonate. In scleractinians, the majority of GAs manifested as hyperplasia of the basal body wall (52% of cases), with an associated absence or reduction of polyp structure (mesenteries and filaments, actinopharynx and tentacles), and depletion of zooxanthellae in the gastrodermis of the upper body wall. In the soft corals Sinularia sp. and Lobophytum sp., GAs exclusively manifested as prominent hyperplasia of the coenenchyme with an increased density of solenia. In contrast to scleractinians, soft coral GAs displayed an inflammatory and necrotizing component with marked edema of the mesoglea, accompanied by infiltrates of variably-sized granular amoebocytes. Fungi, algae, sponges, and Crustacea were present in some scleractinian GAs, but absent in soft coral GAs. Fragmentation of tissues was a common finding in Acropora acuminata and Montipora cf. dilatata colonies with tissue loss, although no obvious causative agents were seen. Discoloration in the zoanthid, Palythoa tuberculosa, was found to be the result of necrosis, while in Lobophytum sp. discoloration was the result of zooxanthellar depletion (bleaching). Soft corals with discoloration or tissue loss showed a marked inflammatory response, however no obvious causative organisms were seen. Lesions that appeared similar at the gross level were revealed to be distinct by microscopy, emphasizing the importance of histopathology. PMID:20709072

  1. Early development, pattern, and reorganization of the planula nervous system in Aurelia (Cnidaria, Scyphozoa).

    PubMed

    Nakanishi, Nagayasu; Yuan, David; Jacobs, David K; Hartenstein, Volker

    2008-10-01

    We examined the development of the nervous system in Aurelia (Cnidaria, Scyphozoa) from the early planula to the polyp stage using confocal and transmission electron microscopy. Fluorescently labeled anti-FMRFamide, antitaurine, and antityrosinated tubulin antibodies were used to visualize the nervous system. The first detectable FMRFamide-like immunoreactivity occurs in a narrow circumferential belt toward the anterior/aboral end of the ectoderm in the early planula. As the planula matures, the FMRFamide-immunoreactive cells send horizontal processes (i.e., neurites) basally along the longitudinal axis. Neurites extend both anteriorly/aborally and posteriorly/orally, but the preference is for anterior neurite extension, and neurites converge to form a plexus at the aboral/anterior end at the base of the ectoderm. In the mature planula, a subset of cells in the apical organ at the anterior/aboral pole begins to show FMRFamide-like and taurine-like immunoreactivity, suggesting a sensory function of the apical organ. During metamorphosis, FMRFamide-like immunoreactivity diminishes in the ectoderm but begins to occur in the degenerating primary endoderm, indicating that degenerating FMRFamide-immunoreactive neurons are taken up by the primary endoderm. FMRFamide-like expression reappears in the ectoderm of the oral disc and the tentacle anlagen of the growing polyp, indicating metamorphosis-associated restructuring of the nervous system. These observations are discussed in the context of metazoan nervous system evolution. PMID:18850237

  2. Evolution of box jellyfish (Cnidaria: Cubozoa), a group of highly toxic invertebrates

    PubMed Central

    Bentlage, Bastian; Cartwright, Paulyn; Yanagihara, Angel A.; Lewis, Cheryl; Richards, Gemma S.; Collins, Allen G.

    2010-01-01

    Cubozoa (Cnidaria: Medusozoa) represents a small clade of approximately 50 described species, some of which cause serious human envenomations. Our understanding of the evolutionary history of Cubozoa has been limited by the lack of a sound phylogenetic hypothesis for the group. Here, we present a comprehensive cubozoan phylogeny based on ribosomal genes coding for near-complete nuclear 18S (small subunit) and 28S (large subunit) and partial mitochondrial 16S. We discuss the implications of this phylogeny for our understanding of cubozoan venom evolution, biogeography and life-history evolution. Our phylogenetic hypothesis suggests that: (i) the last common ancestor of Carybdeida probably possessed the mechanism(s) underlying Irukandji syndrome, (ii) deep divergences between Atlantic and Indo-Pacific clades may be explained by ancient vicariant events, and (iii) sexual dimorphism evolved a single time in concert with complex sexual behaviour. Furthermore, several cubozoan taxa are either para- or polyphyletic, and we address some of these taxonomic issues by designating a new family, Carukiidae, a new genus, Copula, and by redefining the families Tamoyidae and Tripedaliidae. Lastly, cubozoan species identities have long been misunderstood and the data presented here support many of the recent scientific descriptions of cubozoan species. However, the results of a phylogeographic analysis of Alatina moseri from Hawai'i and Alatina mordens from Australia indicate that these two nominal species represent a single species that has maintained metapopulation cohesion by natural or anthropogenic dispersal. PMID:19923131

  3. Gross and microscopic morphology of lesions in Cnidaria from Palmyra Atoll, Central Pacific

    USGS Publications Warehouse

    Williams, Gareth J.; Work, Thierry M.; Aeby, Greta S.; Knapp, Ingrid S.; Davy, Simon K.

    2011-01-01

    We conducted gross and microscopic characterizations of lesions in Cnidaria from Palmyra Atoll, Central Pacific. We found growth anomalies (GA) to be the most commonly encountered lesion. Cases of discoloration and tissue loss were rare. GAs had a focal or multi-focal distribution and were predominantly nodular, exophytic, and umbonate. In scleractinians, the majority of GAs manifested as hyperplasia of the basal body wall (52% of cases), with an associated absence or reduction of polyp structure (mesenteries and filaments, actinopharynx and tentacles), and depletion of zooxanthellae in the gastrodermis of the upper body wall. In the soft corals Sinularia sp. and Lobophytum sp., GAs exclusively manifested as prominent hyperplasia of the coenenchyme with an increased density of solenia. In contrast to scleractinians, soft coral GAs displayed an inflammatory and necrotizing component with marked edema of the mesoglea, accompanied by infiltrates of variably-sized granular amoebocytes. Fungi, algae, sponges, and Crustacea were present in some scleractinian GAs, but absent in soft coral GAs. Fragmentation of tissues was a common finding in Acropora acuminata and Montipora cf. dilatata colonies with tissue loss, although no obvious causative agents were seen. Discoloration in the zoanthid, Palythoa tuberculosa, was found to be the result of necrosis, while in Lobophytum sp. discoloration was the result of zooxanthellar depletion (bleaching). Soft corals with discoloration or tissue loss showed a marked inflammatory response, however no obvious causative organisms were seen. Lesions that appeared similar at the gross level were revealed to be distinct by microscopy, emphasizing the importance of histopathology.

  4. Shallow-water zoantharians (Cnidaria, Hexacorallia) from the Central Indo-Pacific

    PubMed Central

    Reimer, James D.; Poliseno, Angelo; Hoeksema, Bert W.

    2014-01-01

    Abstract Despite the Central Indo-Pacific (CIP) and the Indonesian Archipelago being a well-known region of coral reef biodiversity, particularly in the ‘Coral Triangle’, little published information is available on its zoantharians (Cnidaria: Hexacorallia: Zoantharia). In order to provide a basis for future research on the Indo-Pacific zoantharian fauna and facilitate comparisons between more well-studied regions such as Japan and the Great Barrier Reef, this report deals with CIP zoantharian specimens in the Naturalis collection in Leiden, the Netherlands; 106 specimens were placed into 24 morpho-species and were supplemented with 88 in situ photographic records from Indonesia, the Philippines, and Papua New Guinea. At least nine morpho-species are likely to be undescribed species, indicating that the region needs more research in order to properly understand zoantharian diversity within the CIP. The Naturalis’ zoantharian specimens are listed by species, as well as all relevant collection information, and in situ images are provided to aid in future studies on zoantharians in the CIP. PMID:25349499

  5. A conserved cluster of three PRD-class homeobox genes (homeobrain, rx and orthopedia) in the Cnidaria and Protostomia

    PubMed Central

    2010-01-01

    Background Homeobox genes are a superclass of transcription factors with diverse developmental regulatory functions, which are found in plants, fungi and animals. In animals, several Antennapedia (ANTP)-class homeobox genes reside in extremely ancient gene clusters (for example, the Hox, ParaHox, and NKL clusters) and the evolution of these clusters has been implicated in the morphological diversification of animal bodyplans. By contrast, similarly ancient gene clusters have not been reported among the other classes of homeobox genes (that is, the LIM, POU, PRD and SIX classes). Results Using a combination of in silico queries and phylogenetic analyses, we found that a cluster of three PRD-class homeobox genes (Homeobrain (hbn), Rax (rx) and Orthopedia (otp)) is present in cnidarians, insects and mollusks (a partial cluster comprising hbn and rx is present in the placozoan Trichoplax adhaerens). We failed to identify this 'HRO' cluster in deuterostomes; in fact, the Homeobrain gene appears to be missing from the chordate genomes we examined, although it is present in hemichordates and echinoderms. To illuminate the ancestral organization and function of this ancient cluster, we mapped the constituent genes against the assembled genome of a model cnidarian, the sea anemone Nematostella vectensis, and characterized their spatiotemporal expression using in situ hybridization. In N. vectensis, these genes reside in a span of 33 kb with the same gene order as previously reported in insects. Comparisons of genomic sequences and expressed sequence tags revealed the presence of alternative transcripts of Nv-otp and two highly unusual protein-coding polymorphisms in the terminal helix of the Nv-rx homeodomain. A population genetic survey revealed the Rx polymorphisms to be widespread in natural populations. During larval development, all three genes are expressed in the ectoderm, in non-overlapping territories along the oral-aboral axis, with distinct temporal expression. Conclusion We report the first evidence for a PRD-class homeobox cluster that appears to have been conserved since the time of the cnidarian-bilaterian ancestor, and possibly even earlier, given the presence of a partial cluster in the placozoan Trichoplax. Very similar clusters comprising these three genes exist in Nematostella and diverse protostomes. Interestingly, in chordates, one member of the ancestral cluster (homeobrain) has apparently been lost, and there is no linkage between rx and orthopedia in any of the vertebrates. In Nematostella, the spatial expression of these three genes along the body column is not colinear with their physical order in the cluster but the temporal expression is, therefore, using the terminology that has been applied to the Hox cluster genes, the HRO cluster would appear to exhibit temporal but not spatial colinearity. It remains to be seen whether the mechanisms responsible for the evolutionary conservation of the HRO cluster are the same mechanisms responsible for cohesion of the Hox cluster and other ANTP-class homeobox clusters that have been widely conserved throughout animal evolution. PMID:20849646

  6. A new species of antipatharian coral (Cnidaria: Anthozoa: Antipatharia: Schizopathidae) from the Pacific coast of Costa Rica

    SciTech Connect

    Opresko, Dennis M [ORNL; Breedy, Odalisca [University of Costa Rica

    2010-09-01

    A new species of black coral, Aphanipathes colombiana (Cnidaria:Antipatharia) from the Caribbean coast of Colombia is described. The species forms small flabellate colonies with anisomorphic polypar spines. It is morphologically similar to the western Atlantic species A. thyoides (Pourtales) but its hypostomal polypar spines are not reduced in size. The new species also resembles the Indo-Pacific species A. reticulata van Pesch but it has smooth-surfaced polypar spines, whereas in A. reticulata these spines have small tubercles on their surface

  7. A molecular phylogenetic analysis of the Octocorallia (Cnidaria: Anthozoa) based on mitochondrial protein-coding sequences

    Microsoft Academic Search

    Catherine S. McFadden; Scott C. France; Juan A. Sánchez; Phil Alderslade

    2006-01-01

    Despite their abundance and ecological importance in a wide variety of shallow and deep water marine communities, octocorals (soft corals, sea fans, and sea pens) are a group whose taxonomy and phylogenetic relationships remain poorly known and little studied. The group is currently divided into three orders (O: Alcyonacea, Pennatulacea, and Helioporacea); the large O. Alcyonacea (soft corals and sea

  8. Character evolution in light of phylogenetic analysis and taxonomic revision of the zooxanthellate sea anemone families Thalassianthidae and Aliciidae

    E-print Network

    Crowther, Andrea Louise

    2013-05-31

    Aliciidae and Thalassianthidae look similar because they possess both morphological features of branched outgrowths and spherical defensive structures, and their identification can be confused because of their similarity. ...

  9. vasa and nanos expression patterns in a sea anemone and the evolution of bilaterian germ cell specification mechanisms

    E-print Network

    Extavour, Cassandra

    ctenophores, acoelomorph flatworms, and cnidarians are ca- pable of asexual reproduction by budding, but also germ cells very differently from most extant bilaterians. Cnidarians and sponges have been reported to generate germ cells continuously throughout reproductive life, but previous studies on members

  10. Introducing the starlet sea anemone Nematostella vectensis as a model for investigating microbial mediation of health and disease in hexacorals

    E-print Network

    Har, Jia Yi

    2009-01-01

    All animals in their natural state harbor complex communities of microbes including those that are beneficial (symbionts), neutral, or harmful (pathogens). The dynamic interactions between animals and their microbiota often ...

  11. Nanoporous TiO2 nanoparticle assemblies with mesoscale morphologies: nano-cabbage versus sea-anemone.

    PubMed

    Darbandi, Masih; Gebre, Tesfaye; Mitchell, Lucas; Erwin, William; Bardhan, Rizia; Levan, M Douglas; Mochena, Mogus D; Dickerson, James H

    2014-06-01

    We report the novel synthesis of nanoporous TiO2 nanoparticle ensembles with unique mesoscale morphologies. Constituent nanoparticles evolved into multifaceted assemblies, exhibiting excellent crystallinity and enhanced photocatalytic activity compared with commercial TiO2. Such materials could be exploited for applications, like organic pollutant degradation. PMID:24760418

  12. Internal anatomy of Haliclystus antarcticus (Cnidaria, Staurozoa) with a discussion on histological features used in Staurozoan taxonomy.

    PubMed

    Miranda, Lucília S; Collins, Allen G; Marques, Antonio C

    2013-12-01

    Stauromedusae have relatively few macromorphological characters, making both their taxonomy and identification difficult. For this reason, histological characters are also employed in the taxonomy of the group. This study presents a detailed description of the histomorphology of Haliclystus antarcticus Pfeffer, 1889 (Cnidaria, Staurozoa). We make new observations for the species and for the class, and address functional, taxonomical, and evolutionary aspects of staurozoan histo-anatomy. A complete reconstruction of H. antarcticus body plan is used to guide a more detailed observation, based on light microscopy, of structures rarely cited in the literature, such as the intertentacular lobules, the ostia between adjacent perradial pockets, and the male and female gonadal vesicles. Two possible regions of nematocyst formation are hypothesized and discussed. We also provide a review of the current use of histological characters in the taxonomy of the group. Understanding the body plan of stauromedusae is a challenge, because each single individual presents characters found in medusae and in polyps of other medusozoans. Comprehensive histological descriptions are important to establish relations of homology within Staurozoa and Cnidaria, providing crucial data on their evolution. PMID:24072690

  13. Anemone-like nanostructures for non-lithographic, reproducible, large-area, and ultra-sensitive SERS substrates.

    PubMed

    Daglar, Bihter; Demirel, Gokcen Birlik; Khudiyev, Tural; Dogan, Tamer; Tobail, Osama; Altuntas, Sevde; Buyukserin, Fatih; Bayindir, Mehmet

    2014-11-01

    The melt-infiltration technique enables the fabrication of complex nanostructures for a wide range of applications in optics, electronics, biomaterials, and catalysis. Here, anemone-like nanostructures are produced for the first time under the surface/interface principles of melt-infiltration as a non-lithographic method. Functionalized anodized aluminum oxide (AAO) membranes are used as templates to provide large-area production of nanostructures, and polycarbonate (PC) films are used as active phase materials. In order to understand formation dynamics of anemone-like structures finite element method (FEM) simulations are performed and it is found that wetting behaviour of the polymer is responsible for the formation of cavities at the caps of the structures. These nanostructures are examined in the surface-enhanced-Raman-spectroscopy (SERS) experiment and they exhibit great potential in this field. Reproducible SERS signals are detected with relative standard deviations (RSDs) of 7.2-12.6% for about 10,000 individual spots. SERS measurements are demonstrated at low concentrations of Rhodamine 6G (R6G), even at the picomolar level, with an enhancement factor of ?10(11). This high enhancement factor is ascribed to the significant electric field enhancement at the cavities of nanostructures and nanogaps between them, which is supported by finite difference time-domain (FDTD) simulations. These novel nanostructured films can be further optimized to be used in chemical and plasmonic sensors and as a single molecule SERS detection platform. PMID:25220106

  14. Anemone-like nanostructures for non-lithographic, reproducible, large-area, and ultra-sensitive SERS substrates

    NASA Astrophysics Data System (ADS)

    Daglar, Bihter; Demirel, Gokcen Birlik; Khudiyev, Tural; Dogan, Tamer; Tobail, Osama; Altuntas, Sevde; Buyukserin, Fatih; Bayindir, Mehmet

    2014-10-01

    The melt-infiltration technique enables the fabrication of complex nanostructures for a wide range of applications in optics, electronics, biomaterials, and catalysis. Here, anemone-like nanostructures are produced for the first time under the surface/interface principles of melt-infiltration as a non-lithographic method. Functionalized anodized aluminum oxide (AAO) membranes are used as templates to provide large-area production of nanostructures, and polycarbonate (PC) films are used as active phase materials. In order to understand formation dynamics of anemone-like structures finite element method (FEM) simulations are performed and it is found that wetting behaviour of the polymer is responsible for the formation of cavities at the caps of the structures. These nanostructures are examined in the surface-enhanced-Raman-spectroscopy (SERS) experiment and they exhibit great potential in this field. Reproducible SERS signals are detected with relative standard deviations (RSDs) of 7.2-12.6% for about 10 000 individual spots. SERS measurements are demonstrated at low concentrations of Rhodamine 6G (R6G), even at the picomolar level, with an enhancement factor of ~1011. This high enhancement factor is ascribed to the significant electric field enhancement at the cavities of nanostructures and nanogaps between them, which is supported by finite difference time-domain (FDTD) simulations. These novel nanostructured films can be further optimized to be used in chemical and plasmonic sensors and as a single molecule SERS detection platform.The melt-infiltration technique enables the fabrication of complex nanostructures for a wide range of applications in optics, electronics, biomaterials, and catalysis. Here, anemone-like nanostructures are produced for the first time under the surface/interface principles of melt-infiltration as a non-lithographic method. Functionalized anodized aluminum oxide (AAO) membranes are used as templates to provide large-area production of nanostructures, and polycarbonate (PC) films are used as active phase materials. In order to understand formation dynamics of anemone-like structures finite element method (FEM) simulations are performed and it is found that wetting behaviour of the polymer is responsible for the formation of cavities at the caps of the structures. These nanostructures are examined in the surface-enhanced-Raman-spectroscopy (SERS) experiment and they exhibit great potential in this field. Reproducible SERS signals are detected with relative standard deviations (RSDs) of 7.2-12.6% for about 10 000 individual spots. SERS measurements are demonstrated at low concentrations of Rhodamine 6G (R6G), even at the picomolar level, with an enhancement factor of ~1011. This high enhancement factor is ascribed to the significant electric field enhancement at the cavities of nanostructures and nanogaps between them, which is supported by finite difference time-domain (FDTD) simulations. These novel nanostructured films can be further optimized to be used in chemical and plasmonic sensors and as a single molecule SERS detection platform. Electronic supplementary information (ESI) available: SEM images of the AAO membrane and bare polymer film, FEM simulations of anemone-like polymeric nanopillars depending on the time and pressure, and detailed calculation of the enhancement factor both including experimental and theoretical approaches. See DOI: 10.1039/c4nr03909b

  15. Sea Education Association (SEA)

    NSDL National Science Digital Library

    The Sea Education Association (SEA) in Woods Hole, MA provides undergraduates with an opportunity to participate in an academic study-abroad program called the SEA Semester. The program combines intensive research in the areas of oceanography, maritime studies, and nautical science with hands-on experience aboard a traditional sailing ship. Piloting, celestial navigation, and practical seamanship are learned together with oceanographic sampling techniques and marine laboratory procedures. Critical thinking, problem-solving, team-building and leadership skills are emphasized throughout the program. SEA Semester is appropriate for students in marine biology, geology and physical science, environmental studies, American studies, and most other areas within the liberal arts and sciences. Academic credit for SEA Semester is obtained through Boston University.

  16. Cnidarian microRNAs frequently regulate targets by cleavage

    PubMed Central

    Moran, Yehu; Fredman, David; Praher, Daniela; Li, Xin Z.; Wee, Liang Meng; Rentzsch, Fabian; Zamore, Phillip D.; Technau, Ulrich; Seitz, Hervé

    2014-01-01

    In bilaterians, which comprise most of extant animals, microRNAs (miRNAs) regulate the majority of messenger RNAs (mRNAs) via base-pairing of a short sequence (the miRNA “seed”) to the target, subsequently promoting translational inhibition and transcript instability. In plants, many miRNAs guide endonucleolytic cleavage of highly complementary targets. Because little is known about miRNA function in nonbilaterian animals, we investigated the repertoire and biological activity of miRNAs in the sea anemone Nematostella vectensis, a representative of Cnidaria, the sister phylum of Bilateria. Our work uncovers scores of novel miRNAs in Nematostella, increasing the total miRNA gene count to 87. Yet only a handful are conserved in corals and hydras, suggesting that microRNA gene turnover in Cnidaria greatly exceeds that of other metazoan groups. We further show that Nematostella miRNAs frequently direct the cleavage of their mRNA targets via nearly perfect complementarity. This mode of action resembles that of small interfering RNAs (siRNAs) and plant miRNAs. It appears to be common in Cnidaria, as several of the miRNA target sites are conserved among distantly related anemone species, and we also detected miRNA-directed cleavage in Hydra. Unlike in bilaterians, Nematostella miRNAs are commonly coexpressed with their target transcripts. In light of these findings, we propose that post-transcriptional regulation by miRNAs functions differently in Cnidaria and Bilateria. The similar, siRNA-like mode of action of miRNAs in Cnidaria and plants suggests that this may be an ancestral state. PMID:24642861

  17. Long-term fluctuations of Pelagia noctiluca (Cnidaria, Scyphomedusa) in the western Mediterranean Sea. Prediction by climatic variables

    NASA Astrophysics Data System (ADS)

    Goy, Jacquelinn; Morand, Pierre; Etienne, Michéle

    1989-02-01

    The archives of the Station Zoologique at Villefranche-sur-Mer contain records of "years with Pelagia noctiluca" and 'years without Pelagia". These records, plus additional data, indicate that over the past 200 years (1785-1985) outburst of Pelagia have occured about every 12 years. Using a forecasting model, climatic variables, notably temperature, rainfall and atmospheric pressure, appear to predict "years with Pelagia".

  18. Leptohelia flexibilis gen. nov. et sp. nov., a remarkable deep-sea stylasterid (Cnidaria: Hydrozoa: Stylasteridae) from the southwest Pacific.

    PubMed

    Lindner, Alberto; Cairns, Stephen D; Zibrowius, Helmut

    2014-01-01

    Leptohelia flexibilis gen. nov. et sp. nov., the first stylasterid with a combined calcified and non-calcified skeleton, is described from seamounts and the slope off the islands of New Caledonia, in the southwestern Pacific. The new species is distinguished from all other species of the family Stylasteridae by having a non-calcified organic axis, internal to the basal portion of the calcified corallum. The internal axis is flexible and enclosed by a series of up to 10 calcified annuli, allowing passive lateral bending of the colony. Molecular phylogenetic analyses confirm that Leptohelia flexibilis is a stylasterid coral and reveal that the species is closely related to Leptohelia microstylus comb. nov., a southwestern Pacific stylasterid that lacks an internal axis. PMID:25543758

  19. Substrate choice and settlement preferences of planula larvae of five Scyphozoa (Cnidaria) from German Bight, North Sea

    Microsoft Academic Search

    Sabine Holst; Gerhard Jarms

    2007-01-01

    The settlement behaviour of planula larvae and their development to young polyps was investigated in laboratory experiments\\u000a in five scyphozoan species [Aurelia aurita (L.), Cyanea capillata (L.), Cyanea lamarckii Péron and Leseur, Chrysaora hysoscella (L.), and Rhizostoma octopus (L.)]. The undersides of settling plates were strongly preferred for settlement. Shells, the only natural substrate type\\u000a offered, were less attractive than

  20. Sea Turtles

    NSDL National Science Digital Library

    Sea World informational resource on all eight species of sea turtles. Excellent introduction to sea turtles including information on their classification, habitat, diet, reproduction, and much more. Includes photographs and illustrations throughout. Features two teaching activities for grades K-2.

  1. Yolk formation in a stony coral Euphyllia ancora (Cnidaria, Anthozoa): insight into the evolution of vitellogenesis in nonbilaterian animals.

    PubMed

    Shikina, Shinya; Chen, Chieh-Jhen; Chung, Yi-Jou; Shao, Zi-Fan; Liou, Jhe-Yu; Tseng, Hua-Pin; Lee, Yan-Horn; Chang, Ching-Fong

    2013-09-01

    Vitellogenin (Vg) is a major yolk protein precursor in numerous oviparous animals. Numerous studies in bilateral oviparous animals have shown that Vg sequences are conserved across taxa and that Vgs are synthesized by somatic-cell lineages, transported to and accumulated in oocytes, and eventually used for supporting embryogenesis. In nonbilateral animals (Polifera, Cnidaria, and Ctenophora), which are regarded as evolutionarily primitive, although Vg cDNA has been identified in 2 coral species from Cnidaria, relatively little is known about the characteristics of yolk formation in their bodies. To address this issue, we identified and characterized 2 cDNA encoding yolk proteins, Vg and egg protein (Ep), in the stony coral Euphyllia ancora. RT-PCR analysis revealed that expression levels of both Vg and Ep increased in the female colonies as coral approached the spawning season. In addition, high levels of both Vg and Ep transcripts were detected in the putative ovarian tissue, as determined by tissue distribution analysis. Further analyses using mRNA in situ hybridization and immunohistochemistry determined that, within the putative ovarian tissue, these yolk proteins are synthesized in the mesenterial somatic cells but not in oocytes themselves. Furthermore, Vg proteins that accumulated in eggs were most likely consumed during the coral embryonic development, as assessed by immunoblotting. The characteristics of Vg that we identified in corals were somewhat similar to those of Vg in bilaterian oviparous animals, raising the hypothesis that such characteristics were likely present in the oogenesis of some common ancestor prior to divergence of the cnidarian and bilaterian lineages. PMID:23766130

  2. Mitochondrial genome of the moon jelly Aurelia aurita (Cnidaria, Scyphozoa): A linear DNA molecule encoding a putative DNA-dependent DNA polymerase

    Microsoft Academic Search

    Zhiyong Shao; Shannon Graf; Oleg Y. Chaga; Dennis V. Lavrov

    2006-01-01

    The 16,937-nuceotide sequence of the linear mitochondrial DNA (mt-DNA) molecule of the moon jelly Aurelia aurita (Cnidaria, Scyphozoa) – the first mtDNA sequence from the class Scypozoa and the first sequence of a linear mtDNA from Metazoa – has been determined. This sequence contains genes for 13 energy pathway proteins, small and large subunit rRNAs, and methionine and tryptophan tRNAs.

  3. Red Sea

    Atmospheric Science Data Center

    2013-04-16

    article title:  The Red Sea     View Larger Image ... Multi-angle Imaging SpectroRadiometer (MISR) image of the Red Sea was acquired on August 13, 2000. Located between the East African coast ... the Red Sea got its name because the blooms of a type of algae,  Trichodesmium erythraeum , found in the sea turn reddish-brown when ...

  4. SEA TURTLES Sea Turtles

    E-print Network

    in the United States are currently listed either as endangered or threatened under the Endangered Species Act, Malaysia Hawksbill Endangered Hawaii 1Status under the Endangered Species Act (ESA). 2Sea turtles in the U the world's oceans. Of the seven species found worldwide, six are found in U.S. waters and include

  5. A Comprehensive Phylogenetic Analysis of the Scleractinia (Cnidaria, Anthozoa) Based on Mitochondrial CO1 Sequence Data

    PubMed Central

    Kitahara, Marcelo V.; Cairns, Stephen D.; Stolarski, Jaros?aw; Blair, David; Miller, David J.

    2010-01-01

    Background Classical morphological taxonomy places the approximately 1400 recognized species of Scleractinia (hard corals) into 27 families, but many aspects of coral evolution remain unclear despite the application of molecular phylogenetic methods. In part, this may be a consequence of such studies focusing on the reef-building (shallow water and zooxanthellate) Scleractinia, and largely ignoring the large number of deep-sea species. To better understand broad patterns of coral evolution, we generated molecular data for a broad and representative range of deep sea scleractinians collected off New Caledonia and Australia during the last decade, and conducted the most comprehensive molecular phylogenetic analysis to date of the order Scleractinia. Methodology Partial (595 bp) sequences of the mitochondrial cytochrome oxidase subunit 1 (CO1) gene were determined for 65 deep-sea (azooxanthellate) scleractinians and 11 shallow-water species. These new data were aligned with 158 published sequences, generating a 234 taxon dataset representing 25 of the 27 currently recognized scleractinian families. Principal Findings/Conclusions There was a striking discrepancy between the taxonomic validity of coral families consisting predominantly of deep-sea or shallow-water species. Most families composed predominantly of deep-sea azooxanthellate species were monophyletic in both maximum likelihood and Bayesian analyses but, by contrast (and consistent with previous studies), most families composed predominantly of shallow-water zooxanthellate taxa were polyphyletic, although Acroporidae, Poritidae, Pocilloporidae, and Fungiidae were exceptions to this general pattern. One factor contributing to this inconsistency may be the greater environmental stability of deep-sea environments, effectively removing taxonomic “noise” contributed by phenotypic plasticity. Our phylogenetic analyses imply that the most basal extant scleractinians are azooxanthellate solitary corals from deep-water, their divergence predating that of the robust and complex corals. Deep-sea corals are likely to be critical to understanding anthozoan evolution and the origins of the Scleractinia. PMID:20628613

  6. Increase of litter at the Arctic deep-sea observatory HAUSGARTEN.

    PubMed

    Bergmann, Melanie; Klages, Michael

    2012-12-01

    Although recent research has shown that marine litter has made it even to the remotest parts of our planet, little information is available about temporal trends on the deep ocean floor. To quantify litter on the deep seafloor over time, we analysed images from the HAUSGARTEN observatory (79°N) taken in 2002, 2004, 2007, 2008 and 2011 (2500 m depth). Our results indicate that litter increased from 3635 to 7710 items km?² between 2002 and 2011 and reached densities similar to those reported from a canyon near the Portuguese capital Lisboa. Plastic constituted the majority of litter (59%) followed by a black fabric (11%) and cardboard/paper (7%). Sixty-seven percent of the litter was entangled or colonised by invertebrates such as sponges (41%) or sea anemones (15%). The changes in litter could be an indirect consequence of the receding sea ice, which opens the Arctic Ocean to the impacts of man's activities. PMID:23083926

  7. Sea urchin

    NSDL National Science Digital Library

    N/A N/A (NOAA; Channel Islands National Marine Sanctuary)

    2004-12-23

    The sea urchin is a type of echinoderm. It is a consumer because it cannot make its own food and must eat other organisms to get energy. Sea urchins are omnivores, meaning they eat both plants and other animals to gain energy. Sea urchins have been known to eat algae, mussels, and sponges.

  8. Differences in the protein profiles of cultured and endosymbiotic symbiodinium sp. (pyrrophyta) from the anemone aiptasia pallida (anthozoa)

    SciTech Connect

    Stochaj, W.R.; Grossman, A.R. [Carnegie Institution of Washington, Stanford, CA (United States)

    1997-02-01

    One- and two-dimensional sodium dodecylsulfate-polyacrylamide gel electrophoresis and immunological analyses were used to visualize differences in polypeptides synthesized by Symbiodinium sp. from the anemone Aiptasia pallida when grown in the cultured and endosymbiotic states (freshly isolated zooxanthellae). Surprisingly, a comparison of proteins in cultured and endosymbiotic Symbiodinium sp. revealed only four major polypeptides with similar isoelectric and molecular mass characteristics. Using monospecific antibodies, we demonstrated differences in specific proteins synthesized by the dinoflagellate in the two different growth states. The dimeric, 14 kDa form of the peripheral membrane peridinin-chlorophyll a binding protein predominates under endosymbiotic conditions, whereas the monomeric, 35 kDa form predominates under the culture conditions used in this study. Antibodies to form II ribulose-1,5-bisphosphate carboxylase revealed 62 and 60 kDa forms of this protein in the alga grown as an endosymbiont and in culture, respectively. Differences in the integral membrane peridinin-chlorophyll a-c-binding proteins were also observed. These results demonstrate that there are major changes in the populations of proteins synthesized by Symbiodinium sp. in response to the conditions in hospite. Such changes may reflect a developmental switch that tailors the physiology of the alga to the conditions encountered in the endosymbiotic state. 77 refs., 6 figs.

  9. The impact of invasive grasses on the population growth of Anemone patens, a long-lived native forb.

    PubMed

    Williams, Jennifer L; Crone, Elizabeth E

    2006-12-01

    Negative impacts of invasive plants on natives have been well documented, but much less is known about whether invasive plants can cause population level declines. We used demographic models to investigate the effects of two invasive grasses on the demography and population growth of Anemone patens, a long-lived native perennial of North American grasslands. Demographic data of A. patens growing in patches characterized by Bromus inermis, Poa pratensis, or native grasses were used to parameterize integral projection models. Models based on both average conditions and those allowing for environmental stochasticity indicate that A. patens is slowly increasing in patches of native grass (lambda = 1.02) and declining in patches of invasive grasses, particularly those dominated by B. inermis (lambda = 0.93). Extinction probabilities indicate that A. patens should persist in native grass patches, but has a much higher probability of extinction in Bromus patches compared to Poa patches. While sensitivity analyses showed that survival had the biggest effect on population growth rates in all habitats, results of a Life Table Response Experiment (LTRE) revealed that slower individual growth rates in patches of invasive grasses contributed the most to the observed reduction in population growth. These results suggest that invasive grasses may cause slow declines in A. patens, despite short-term coexistence, and that controlling B. inermis only would not be sufficient to ensure A. patens persistence. PMID:17249243

  10. Wnt signaling in the early sea urchin embryo.

    PubMed

    Kumburegama, Shalika; Wikramanayake, Athula H

    2008-01-01

    Wnt signaling regulates a remarkably diverse array of cellular and developmental events during animal embryogenesis and homeostasis. The crucial role that Wnt signaling plays in regulating axial patterning in early embryos has been particularly striking. Recent work has highlighted the conserved role that canonical Wnt signaling plays in patterning the animal-vegetal (A-V) axis in sea urchin and sea anemone embryos. In sea urchin embryos, the canonical Wnt signaling pathway is selectively turned on in vegetal cells as early as the 16-cell stage embryo, and signaling through this pathway is required for activation of the endomesodermal gene regulatory network. Loss of nuclear beta-catenin signaling animalizes the sea urchin embryo and blocks pattern formation along the entire A-V axis. Nuclear entry of beta-catenin into vegetal cells is regulated cell autonomously by maternal information that is present at the vegetal pole of the unfertilized egg. Analysis of Dishevelled (Dsh) regulation along the A-V axis has revealed the presence of a cytoarchitectural domain at the vegetal pole of the unfertilized sea urchin egg. This vegetal cortical domain appears to be crucial for the localized activation of Dsh at the vegetal pole, but the precise mechanisms are unknown. The elucidation of how Dsh is selectively activated at the vegetal cortical domain is likely to provide important insight into how this enigmatic protein is regulated during canonical Wnt signaling. Additionally, this information will shed light on the origins of embryonic polarity during animal evolution. This chapter examines the roles played by the canonical Wnt signaling pathway in the specification and patterning of the A-V axis in the sea urchin. These studies have led to the identification of a novel role for canonical Wnt signaling in regulating protein stability, and continued studies of Wnt signaling in this model system are likely to reveal additional roles for this pathway in regulating early patterning events in embryos. PMID:19109711

  11. Expression of Wnt pathway genes in polyps and medusa-like structures of Ectopleura larynx (Cnidaria: Hydrozoa).

    PubMed

    Nawrocki, Annalise M; Cartwright, Paulyn

    2013-01-01

    The canonical Wnt signaling pathway is conserved in its role in axial patterning throughout Metazoa. In some hydrozoans (Phylum Cnidaria), Wnt signaling is implicated in oral-aboral patterning of the different life cycle stages-the planula, polyp and medusa. Unlike most hydrozoans, members of Aplanulata lack a planula larva and the polyp instead develops directly from a brooded or encysted embryo. The Aplanulata species Ectopleura larynx broods such embryos within gonophores. These gonophores are truncated medusae that remain attached to the polyps from which they bud, and retain evolutionary remnants of medusa structures. In E. larynx, gonophores differ between males and females in their degree of medusa truncation, making them an ideal system for examining truncated medusa development. Using next-generation sequencing, we isolated genes from Wnt signaling pathways and examined their expression in E. larynx. Our data are consistent with the Wnt pathway being involved in axial patterning of the polyp and truncated medusa. Changes in the spatial expression of Wnt pathway genes are correlated with the development of different oral structures in male and female gonophores. The absence of expression of components of the Wnt pathway and presence of a Wnt pathway antagonist SFRP in the developing anterior end of the gonophore suggest that downregulation of the Wnt pathway could play a role in medusa reduction in E. larynx. PMID:24074282

  12. A new species of hydra (Cnidaria: Hydrozoa: Hydridae) and molecular phylogenetic analysis of six congeners from China.

    PubMed

    Wang, An-Tai; Deng, Li; Liu, Hong-Tao

    2012-12-01

    A new species of genus Hydra (Cnidaria: Hydrozoa: Hydridae), Hydra shenzhensis sp. nov. from Guangdong Province, China, is described and illustrated. Most polyps have five tentacles. Column length reaches 11 mm when relaxed. Buds do not acquire tentacles synchronously. Stenotele is broad and pyriform in shape, 1.2 times as long as its width. Holotrichous isorhiza is asymmetrical and slender (more than 2.7 times as long as its width), with transverse and slanting coils. Atrichous isorhiza is long, resembling a melon-seed in shape. Desmoneme is asymmetrically pyriform in shape. The new species, belonging to the vulgaris group, is dioecious; sexual reproduction was found to occur mostly during November and December under conditions of dense culture or food shortage. Two to thirteen testes, cone-like shape with papilla, formed beneath the tentacles. One to three ovaries, with an egg cup, milky white in color, formed on body column. Ninety percent of individuals developed only one ovum. On a mother polyp, a fertilized ovum developed an embryonic theca covering its surface. The embryotheca is brown, with a spine-like structure, covering a layer of transparent, membrane-like material. For phylogenetic analysis, the mitochondrial cytochrome oxidase subunit I gene (COI) of six hydra species collected from China was amplified by polymerase chain reaction (PCR) and sequenced. Morphological characters in combination with molecular evidence support the hydra described here as a new species. PMID:23215978

  13. A Diploblastic Radiate Animal at the Dawn of Cambrian Diversification with a Simple Body Plan: Distinct from Cnidaria?

    PubMed Central

    Yasui, Kinya; Reimer, James D.; Liu, Yunhuan; Yao, Xiaoyong; Kubo, Daisuke; Shu, Degan; Li, Yong

    2013-01-01

    Background Microfossils of the genus Punctatus include developmental stages such as blastula, gastrula, and hatchlings, and represent the most complete developmental sequence of animals available from the earliest Cambrian. Despite the extremely well-preserved specimens, the evolutionary position of Punctatus has relied only on their conical remains and they have been tentatively assigned to cnidarians. We present a new interpretation of the Punctatus body plan based on the developmental reconstruction aided by recent advances in developmental biology. Results Punctatus developed from a rather large egg, gastrulated in a mode of invagination from a coeloblastura, and then formed a mouth directly from the blastopore. Spiny benthic hatchlings were distinguishable from swimming or crawling ciliate larvae found in cnidarians and sponges. A mouth appeared at the perihatching embryonic stage and was renewed periodically during growth, and old mouths transformed into the body wall, thus elongating the body. Growing animals retained a small blind gut in a large body cavity without partitioning by septa and did not form tentacles, pedal discs or holdfasts externally. A growth center at the oral pole was sufficient for body patterning throughout life, and the body patterning did not show any bias from radial symmetry. Conclusions Contrary to proposed cnidarian affinity, the Punctatus body plan has basic differences from that of cnidarians, especially concerning a spacious body cavity separating ectoderm from endoderm. The lack of many basic cnidarian characters in the body patterning of Punctatus leads us to consider its own taxonomic group, potentially outside of Cnidaria. PMID:23840375

  14. Reproduction of Dendronephthya hemprichi (Cnidaria: Octocorallia): year-round spawning in an azooxanthellate soft coral

    Microsoft Academic Search

    M. Dahan; Y. Benayahu

    1997-01-01

    Sexual reproduction in the azooxanthellate octocoral Dendronephthya hemprichi Klunzinger, 1877 was studied in Eilat (Red Sea) for 2 years beginning March 1989. D. hemprichi is a gonochoric broadcasting species. Gonads at all developmental stages were found throughout the year. Small-sized oocytes\\u000a and sperm sacs, 51 to 100 ?m in diameter, are highly abundant, accompanied by numerous smaller primordial gonads. These

  15. Small-scale distribution of deep-sea demersal nekton and other megafauna in the Charlie-Gibbs Fracture Zone of the Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Felley, J. D.; Vecchione, M.; Wilson, R. R., Jr.

    2008-01-01

    Videotapes from manned submersibles diving in the area of the Charlie-Gibbs Fracture Zone of the Mid-Atlantic Ridge were used to investigate the distribution of fishes, large crustaceans, epifaunal and sessile organisms, and environmental features along a series of transects. Submersibles MIR 1 and MIR 2 conducted paired dives in an area of mixed sediment and rock (beginning depth ca. 3000 m) and on a large pocket of abyssal-like sediments (depth ca. 4000 m). In the shallower area, the submersibles passed over extremely heterogeneous terrain with a diversity of nekton, epifaunal forms and sessile forms. In the first pair of dives, MIR 1 rose along the Mid-Atlantic Ridge from 3000 to 1700 m, while MIR 2 remained near the 3000 m isobath. Nekton seen in these relatively shallow dives included large and small macrourids (genus Coryphaenoides), shrimp (infraorder Penaeidea), Halosauropsis macrochir, Aldrovandia sp., Antimora rostrata, and alepocephalids. The last two were more characteristic of the upper areas of the slope reached by MIR 1, as it rose along the Mid-Atlantic Ridge to depths less than 3000 m. Distributions of some forms seemed associated with depth and/or the presence of hard substrate. Sessile organisms such as sponges and large cnidaria were more likely to be found in rocky areas. The second pair of dives occurred in an abyssal area and the submersibles passed over sediment-covered plains, with little relief and many fewer countable organisms and features. The most evident of these were holes, mounds, small cerianthid anemones, small macrourids and the holothurian Benthodytes sp. A few large macrourids and shrimp also were seen in these deeper dives, as well as squat lobsters ( Munidopsis sp.). Sponges and larger cnidaria were mostly associated with a few small areas of rocky substrate. Holes and mounds showed distributions suggesting large-scale patterning. Over all dives, most sessile and epifaunal forms showed clumped distributions. However, large holothurians and large nekton often had distributions not significantly different from random.

  16. Sea Stars

    NSDL National Science Digital Library

    2012-07-28

    At first glance, starfish, more properly called sea stars, aren’t doing much of anything. In this video, Jonathan’s investigations reveal a slow-motion predator that hunts and attacks its prey. Traveling the world, Jonathan investigates sea stars from the tropics to the Antarctic and uses time-lapse photography to reveal an amazing complexity to the world of the sea star. Please see the accompanying study guide for educational objectives and discussion points.

  17. Sea Chest

    NSDL National Science Digital Library

    By exploring life at sea for sailors and passengers, the Maritime Museum of San Diego offers insight into the history of maritime exploration, emigration, and commerce. Background and classroom activities are applicable to history, geography, social studies, science, art and other subjects. Emphasis on 19th Century sea travel and sailing ships, with topics including navigation techniques and technology, sailor's crafts, health and medicine at sea, shipboard life and social interactions.

  18. Comparison of morphological and genetic analyses reveals cryptic divergence and morphological plasticity in Stylophora (Cnidaria, Scleractinia)

    NASA Astrophysics Data System (ADS)

    Stefani, Fabrizio; Benzoni, F.; Yang, S.-Y.; Pichon, M.; Galli, P.; Chen, C. A.

    2011-12-01

    A combined morphological and genetic study of the coral genus Stylophora investigated species boundaries in the Gulf of Aden, Yemen. Two mitochondrial regions, including the hypervariable IGS9 spacer and the control region, and a fragment of rDNA were used for phylogenetic analysis. Results were compared by multivariate analysis on the basis of branch morphology and corallite morphometry. Two species were clearly discriminated by both approaches. The first species was characterised by small corallites and a low morphological variability and was ascribed to a new geographical record of Stylophora madagascarensis on the basis of its phylogenetic distinction and its morphological similarity to the type material. The second species was characterised by larger corallite size and greater morphological variability and was ascribed to Stylophora pistillata. The analysis was extended to the intrageneric level for other S. pistillata populations from the Red Sea and the Pacific Ocean. Strong internal divergence was evident in the genus Sty lophora. S. pistillata populations were split into two highly divergent Red Sea/Gulf of Aden and western Pacific lineages with significant morphological overlap, which suggests they represent two distinct cryptic species. The combined use of morphological and molecular approaches, so far proved to be a powerful tool for the re-delineation of species boundaries in corals, provided novel evidence of cryptic divergence in this group of marine metazoans.

  19. Development of Microsatellite Markers in the Deep-Sea Cup Coral Desmophyllum dianthus by 454 Sequencing and Cross-Species Amplifications in Scleractinia Order.

    PubMed

    Addamo, Anna M; García-Jiménez, Ricardo; Taviani, Marco; Machordom, Annie

    2015-01-01

    Microsatellite loci were isolated for the first time for the deep-sea coral Desmophyllum dianthus, using 454 GS-FLX Titanium pyrosequencing. We developed conditions for amplifying 24 markers in 10 multiplex reactions. Three to 16 alleles per locus were detected across 25 samples analyzed from Santa Maria di Leuca coral province (Mediterranean Sea). For the 24 polymorphic loci, observed and expected heterozygosities ranged from 0.211 to 0.880 and 0.383 to 0.910, respectively; 3 loci deviated from Hardy-Weinberg equilibrium, after null allele and sequential Holm-Bonferroni corrections. These newly isolated microsatellites are very useful genetic markers that provide data for future conservation strategies. Cross-amplification of these microsatellites, tested in 46 coral species, representing 40 genera, and 10 families of the phylum Cnidaria, produced informative allelic profiles for 1 to 24 loci. The utility of extending analyses to cross-species amplifications is also discussed. PMID:25810120

  20. Sea Turtles

    NSDL National Science Digital Library

    2012-07-26

    In Malaysia there is an island known for more sea turtles than virtually anywhere on Earth. In this video, Jonathan visits this amazing ecosystem to learn about the life cycle of sea turtles. He is surprised to discover an amazingly complex and competitive environment. Please see the accompanying study guide for educational objectives and discussion points.

  1. Sea turtles

    Microsoft Academic Search

    Catherine M. F. Lohmann; Kenneth J. Lohmann

    2006-01-01

    odern sea turtles are an important component of a wide range of tropical, temperate, and cold water marine ecosystems . Their inclusion on various lists of endangered specie s reflects past over-exploitation and the current need for better management . Today, seven or eight species of sea turtles are recognised, in two families and six genera. Adults typically migrate between

  2. SYSTEMATIC MOTION OF FINE-SCALE JETS AND SUCCESSIVE RECONNECTION IN SOLAR CHROMOSPHERIC ANEMONE JET OBSERVED WITH THE SOLAR OPTICAL TELESCOPE/HINODE

    SciTech Connect

    Singh, K. A. P.; Nishida, K.; Shibata, K. [Kwasan and Hida Observatories, Graduate School of Science, Kyoto University, Yamashina, Kyoto 607-8471 (Japan); Isobe, H., E-mail: singh@kwasan.kyoto-u.ac.jp [Unit for Synergetic Study for Space, Kyoto University, Yamashina, Kyoto 607-8471 (Japan)

    2012-11-20

    The Solar Optical Telescope (SOT) on board Hinode allows observations with high spatiotemporal resolution and stable image quality. A {lambda}-shaped chromospheric anemone jet was observed in high resolution with SOT/Hinode. We found that several fine-scale jets were launched from one end of the footpoint to the other. These fine-scale jets ({approx}1.5-2.5 Mm) gradually move from one end of the footpoint to the other and finally merge into a single jet. This process occurs recurrently, and as time progresses the jet activity becomes more and more violent. The time evolution of the region below the jet in Ca II H filtergram images taken with SOT shows that various parts (or knots) appear at different positions. These bright knots gradually merge into each other during the maximum phase. The systematic motion of the fine-scale jets is observed when different knots merge into each other. Such morphology would arise due to the emergence of a three-dimensional twisted flux rope in which the axial component (or the guide field) appears in the later stages of the flux rope emergence. The partial appearance of the knots could be due to the azimuthal magnetic field that appears during the early stage of the flux rope emergence. If the guide field is strong and reconnection occurs between the emerging flux rope and an ambient magnetic field, this could explain the typical feature of systematic motion in chromospheric anemone jets.

  3. Cnidarian phylogenetic relationships as revealed by mitogenomics

    PubMed Central

    2013-01-01

    Background Cnidaria (corals, sea anemones, hydroids, jellyfish) is a phylum of relatively simple aquatic animals characterized by the presence of the cnidocyst: a cell containing a giant capsular organelle with an eversible tubule (cnida). Species within Cnidaria have life cycles that involve one or both of the two distinct body forms, a typically benthic polyp, which may or may not be colonial, and a typically pelagic mostly solitary medusa. The currently accepted taxonomic scheme subdivides Cnidaria into two main assemblages: Anthozoa (Hexacorallia?+?Octocorallia) – cnidarians with a reproductive polyp and the absence of a medusa stage – and Medusozoa (Cubozoa, Hydrozoa, Scyphozoa, Staurozoa) – cnidarians that usually possess a reproductive medusa stage. Hypothesized relationships among these taxa greatly impact interpretations of cnidarian character evolution. Results We expanded the sampling of cnidarian mitochondrial genomes, particularly from Medusozoa, to reevaluate phylogenetic relationships within Cnidaria. Our phylogenetic analyses based on a mitochogenomic dataset support many prior hypotheses, including monophyly of Hexacorallia, Octocorallia, Medusozoa, Cubozoa, Staurozoa, Hydrozoa, Carybdeida, Chirodropida, and Hydroidolina, but reject the monophyly of Anthozoa, indicating that the Octocorallia?+?Medusozoa relationship is not the result of sampling bias, as proposed earlier. Further, our analyses contradict Scyphozoa [Discomedusae?+?Coronatae], Acraspeda [Cubozoa?+?Scyphozoa], as well as the hypothesis that Staurozoa is the sister group to all the other medusozoans. Conclusions Cnidarian mitochondrial genomic data contain phylogenetic signal informative for understanding the evolutionary history of this phylum. Mitogenome-based phylogenies, which reject the monophyly of Anthozoa, provide further evidence for the polyp-first hypothesis. By rejecting the traditional Acraspeda and Scyphozoa hypotheses, these analyses suggest that the shared morphological characters in these groups are plesiomorphies, originated in the branch leading to Medusozoa. The expansion of mitogenomic data along with improvements in phylogenetic inference methods and use of additional nuclear markers will further enhance our understanding of the phylogenetic relationships and character evolution within Cnidaria. PMID:23302374

  4. Sea Level

    NSDL National Science Digital Library

    This problem provides an opportunity to increase familiarity with negative and positive numbers on a number line. The vertical number line is presented as black markings every one meter all the way up a lighthouse and on the underwater support going down to the sea bed, with sea level being "0". In answering the nine questions, children begin to calculate with negative numbers in the context of the distances between the sea creatures. The Teachers' Notes page offers suggestions for implementation, discussion questions, ideas for extension and support, and a link to a related resource, Swimming Pool (cataloged separately).

  5. The evolution of the four subunits of voltage-gated calcium channels: ancient roots, increasing complexity, and multiple losses.

    PubMed

    Moran, Yehu; Zakon, Harold H

    2014-09-01

    The alpha subunits of voltage-gated calcium channels (Ca(v)s) are large transmembrane proteins responsible for crucial physiological processes in excitable cells. They are assisted by three auxiliary subunits that can modulate their electrical behavior. Little is known about the evolution and roles of the various subunits of Ca(v)s in nonbilaterian animals and in nonanimal lineages. For this reason, we mapped the phyletic distribution of the four channel subunits and reconstructed their phylogeny. Although alpha subunits have deep evolutionary roots as ancient as the split between plants and opistokonths, beta subunits appeared in the last common ancestor of animals and their close-relatives choanoflagellates, gamma subunits are a bilaterian novelty and alpha2/delta subunits appeared in the lineage of Placozoa, Cnidaria, and Bilateria. We note that gene losses were extremely common in the evolution of Ca(v)s, with noticeable losses in multiple clades of subfamilies and also of whole Ca(v) families. As in vertebrates, but not protostomes, Ca(v) channel genes duplicated in Cnidaria. We characterized by in situ hybridization the tissue distribution of alpha subunits in the sea anemone Nematostella vectensis, a nonbilaterian animal possessing all three Ca(v) subfamilies common to Bilateria. We find that some of the alpha subunit subtypes exhibit distinct spatiotemporal expression patterns. Further, all six sea anemone alpha subunit subtypes are conserved in stony corals, which separated from anemones 500 MA. This unexpected conservation together with the expression patterns strongly supports the notion that these subtypes carry unique functional roles. PMID:25146647

  6. Sea Legs

    NASA Astrophysics Data System (ADS)

    Macdonald, Kenneth C.

    Forty-foot, storm-swept seas, Spitzbergen polar bears roaming vast expanses of Arctic ice, furtive exchanges of forbidden manuscripts in Cold War Moscow, the New York city fashion scene, diving in mini-subs to the sea floor hot srings, life with the astronauts, romance and heartbreak, and invading the last bastions of male exclusivity: all are present in this fast-moving, non-fiction account of one woman' fascinating adventures in the world of marine geology and oceanography.

  7. Functional analysis of Wnt signaling in the early sea urchin embryo using mRNA microinjection.

    PubMed

    Bince, Joanna M; Wikramanayake, Athula H

    2008-01-01

    The Wnt pathway is a highly conserved signal transduction pathway that plays many critical roles in early animal development. Recent studies have shown that this pathway plays a conserved role in the specification and patterning of the animal-vegetal (A-V) axis in sea urchins and sea anemones. These observations have suggested that the common ancestor to cnidarians and bilaterians used the Wnt signaling pathway for specifying and patterning this maternally established axis. Because the A-V axis plays a critical role in germ layer segregation, a better understanding of how the Wnt pathway is regulated along the A-V axis will provide key insight into the molecular mechanisms regulating germ layer segregation and germ layer evolution in animal embryos. Here, we provide a detailed protocol for using mRNA microinjection that can be used to analyze Wnt signaling in early sea urchin embryos. This protocol can also be adapted to introduce morpholino anti-sense oligonucleotides into sea urchin embryos. PMID:19109713

  8. Marine Biodiversity ISSN 1867-1616

    E-print Network

    Benayahu, Yehuda

    of Saudi Arabian Red Sea octocorals (Cnidaria: Alcyonacea) Roxanne D. Haverkort-Yeh, Catherine S. Mc at link.springer.com". #12;ORIGINAL PAPER A taxonomic survey of Saudi Arabian Red Sea octocorals (Cnidaria

  9. Spatiotemporal characteristics and mechanisms of intracellular Ca(2+) increases at fertilization in eggs of jellyfish (Phylum Cnidaria, Class Hydrozoa).

    PubMed

    Deguchi, Ryusaku; Kondoh, Eri; Itoh, Junko

    2005-03-15

    We have clarified, for the first time, the spatiotemporal patterns of intracellular Ca(2+) increases at fertilization and the Ca(2+)-mobilizing mechanisms in eggs of hydrozoan jellyfish, which belong to the evolutionarily old diploblastic phylum, Cnidaria. An initial Ca(2+) increase just after fertilization took the form of a Ca(2+) wave starting from one cortical region of the egg and propagating to its antipode in all of four hydrozoan species tested: Cytaeis uchidae, Cladonema pacificum, Clytia sp., and Gonionema vertens. The initiation site of the Ca(2+) wave was restricted to the animal pole, which is known to be the only area of sperm-egg fusion in hydrozoan eggs, and the wave propagating velocity was estimated to be 4.2-5.9 mum/s. After a Ca(2+) peak had been attained by the initial Ca(2+) wave, the elevated Ca(2+) gradually declined and returned nearly to the resting value at 7-10 min following fertilization. Injection of inositol 1,4,5-trisphosphate (IP(3)), an agonist of IP(3) receptors (IP(3)R), was highly effective in inducing a Ca(2+) increase in unfertilized eggs; IP(3) at a final intracellular concentration of 12-60 nM produced a fully propagating Ca(2+) wave equivalent to that observed at fertilization. In contrast, a higher concentration of cyclic ADP-ribose (cADPR), an agonist of ryanodine receptors (RyR), only generated a localized Ca(2+) increase that did not propagate in the egg. In addition, caffeine, another stimulator of RyR, was completely without effect. Sperm-induced Ca(2+) increases in Gonionema eggs were severely affected by preinjection of heparin, an inhibitor of Ca(2+) release from IP(3)R. These results strongly suggest that there is a well-developed IP(3)R-, but not RyR-mediated Ca(2+) release mechanism in hydrozoan eggs and that the former system primarily functions at fertilization. Our present data also demonstrate that the spatial characteristics and mechanisms of Ca(2+) increases at fertilization in hydrozoan eggs resemble those reported in higher triploblastic animals. PMID:15733659

  10. Student Experiments at Sea (SEAS)

    NSDL National Science Digital Library

    Interdisciplinary curriculum introduces the scientific process, experimental design and data analysis. Units on plate tectonics, hydrothermal vents, ridge visualization, surveying deep sea organisms. Students become the scientists, developing proposals for at-sea investigations, teacher coordinates submission to researchers studying the East Pacific Rise. Students retrieve, organize, analyze and report data from their experiment. Past experimental journals are posted. Free registration required to access curriculum and submit proposal.

  11. Sea level trends in South East Asian Seas (SEAS)

    NASA Astrophysics Data System (ADS)

    Strassburg, M. W.; Hamlington, B. D.; Leben, R. R.; Manurung, P.; Lumban Gaol, J.; Nababan, B.; Vignudelli, S.; Kim, K.-Y.

    2014-10-01

    Southeast Asian Seas (SEAS) span the largest archipelago in the global ocean and provide a complex oceanic pathway connecting the Pacific and Indian Oceans. The SEAS regional sea level trends are some of the highest observed in the modern satellite altimeter record that now spans almost two decades. Initial comparisons of global sea level reconstructions find that 17 year sea level trends over the past 60 years exhibit good agreement in areas and at times of strong signal to noise associated decadal variability forced by low frequency variations in Pacific trade winds. The SEAS region exhibits sea level trends that vary dramatically over the studied time period. This historical variation suggests that the strong regional sea level trends observed during the modern satellite altimeter record will abate as trade winds fluctuate on decadal and longer time scales. Furthermore, after removing the contribution of the Pacific Decadal Oscillation (PDO) to sea level trends in the past twenty years, the rate of sea level rise is greatly reduced in the SEAS region. As a result of the influence of the PDO, the SEAS regional sea level trends during 2010s and 2020s are likely to be less than the global mean sea level (GMSL) trend if the observed oscillations in wind forcing and sea level persist. Nevertheless, long-term sea level trends in the SEAS will continue to be affected by GMSL rise occurring now and in the future.

  12. The biology and ecology of black corals (Cnidaria: Anthozoa: Hexacorallia: Antipatharia).

    PubMed

    Wagner, Daniel; Luck, Daniel G; Toonen, Robert J

    2012-01-01

    Antipatharians, commonly known as black corals, are treasured by many cultures for medicinal purposes and to produce jewellery. Despite their economic and cultural importance, very little is known about the basic biology and ecology of black corals because most species inhabit deeper-water environments (>50m) which are logistically challenging to study. There has been a recent increase of studies focusing on antipatharians; however, these have not yet been comprehensively reviewed. This literature review seeks to summarize the available information on the biology and ecology of antipatharians. Although black corals occur throughout all oceans and from subtidal to abyssal depths, they are particularly common in tropical and subtropical regions at depths below 50m. Antipatharians are generally found in areas with hard substrates, low-light and strong currents. Under favourable conditions, some black coral species form dense aggregations to the point of becoming ecologically dominant. Zooplankton appears to be the major component of the diet of black corals, which feed as suspension feeders and use mucus and nematocysts to capture their prey. Previously categorized as azooxanthellate corals, recent research has revealed that many antipatharians appear capable of harbouring symbionts, but unlike other corals, dinoflagellates of the genus Symbiodinium are generally not important to the nutrition of black corals. Antipatharians reproduce through both sexual and asexual processes. In general, polyps and colonies are gonochoric, with fertilization and larval development likely occurring externally; however, to date antipatharian larvae have only been observed for a single species. Antipatharians are generally slow-growing and long-lived organisms with maximum longevities ranging from decades to millennia. Black corals are more abundant with depth, a pattern which has been hypothesized to avoid competition with obligate photosynthetic fauna. Additionally, antipatharians may compete for space by using sweeper tentacles and secondary metabolites. With the exception of a few predators such as gastropods and green sea turtles, antipatharians appear to be little impacted by predation. Like other corals, antipatharians can be habitat engineers of importance to a myriad of associated organisms including arthropods, annelids, echinoderms, mollusks, sponges and cnidarians, several of which are adapted to live exclusively on black corals. Given that most black coral species inhabit remote environments, our understanding of these organisms will depend on our ability to effectively sample and study them. Future collections, particularly in deeper waters (>50m), will be needed to determine whether antipatharian species have limited biogeographical distributions or whether this has simply been an artefact of low sampling efforts away from population centres and taxonomic uncertainties within this group. Additionally, biological and ecological studies require increased sample sizes because most information is currently derived from the examination of only a handful of specimens. PMID:22877611

  13. Biomass of Scyphozoan Jellyfish, and Its Spatial Association with 0-Group Fish in the Barents Sea

    PubMed Central

    Eriksen, Elena; Prozorkevich, Dmitry; Trofimov, Aleksandr; Howell, Daniel

    2012-01-01

    An 0-group fish survey is conducted annually in the Barents Sea in order to estimate fish population abundance. Data on jellyfish by-catch have been recorded since 1980, although this dataset has never been analysed. In recent years, however, the ecological importance of jellyfish medusae has become widely recognized. In this paper the biomass of jellyfish (medusae) in 0–60 m depths is calculated for the period 1980–2010. During this period the climate changed from cold to warm, and changes in zooplankton and fish distribution and abundance were observed. This paper discusses the less well known ecosystem component; jellyfish medusae within the Phylum Cnidaria, and their spatial and temporal variation. The long term average was ca. 9×108 kg, with some years showing biomasses in excess of 5×109 kg. The biomasses were low during 1980s, increased during 1990s, and were highest in early 2000s with a subsequent decline. The bulk of the jellyfish were observed in the central parts of the Barents Sea, which is a core area for most 0-group fishes. Jellyfish were associated with haddock in the western area, with haddock and herring in the central and coastal area, and with capelin in the northern area of the Barents Sea. The jellyfish were present in the temperature interval 1°CSea jellyfish medusae; however their biomass has showed a recent moderate decline during years with record high temperatures in the Barents Sea. Jellyfish are undoubtedly an important component of the Barents Sea ecosystem, and the data presented here represent the best summary of jellyfish biomass and distribution yet published for the region. PMID:22457732

  14. Biomass of scyphozoan jellyfish, and its spatial association with 0-group fish in the Barents Sea.

    PubMed

    Eriksen, Elena; Prozorkevich, Dmitry; Trofimov, Aleksandr; Howell, Daniel

    2012-01-01

    An 0-group fish survey is conducted annually in the Barents Sea in order to estimate fish population abundance. Data on jellyfish by-catch have been recorded since 1980, although this dataset has never been analysed. In recent years, however, the ecological importance of jellyfish medusae has become widely recognized. In this paper the biomass of jellyfish (medusae) in 0-60 m depths is calculated for the period 1980-2010. During this period the climate changed from cold to warm, and changes in zooplankton and fish distribution and abundance were observed. This paper discusses the less well known ecosystem component; jellyfish medusae within the Phylum Cnidaria, and their spatial and temporal variation. The long term average was ca. 9×10? kg, with some years showing biomasses in excess of 5×10? kg. The biomasses were low during 1980s, increased during 1990s, and were highest in early 2000s with a subsequent decline. The bulk of the jellyfish were observed in the central parts of the Barents Sea, which is a core area for most 0-group fishes. Jellyfish were associated with haddock in the western area, with haddock and herring in the central and coastal area, and with capelin in the northern area of the Barents Sea. The jellyfish were present in the temperature interval 1°CSea jellyfish medusae; however their biomass has showed a recent moderate decline during years with record high temperatures in the Barents Sea. Jellyfish are undoubtedly an important component of the Barents Sea ecosystem, and the data presented here represent the best summary of jellyfish biomass and distribution yet published for the region. PMID:22457732

  15. Savage Seas

    NSDL National Science Digital Library

    This companion site to the new PBS series offers a collection of informative pieces and activities centered around the world's oceans. The site is divided into four principal sections, each of which features an article, brief sidebars, video clips, and in some cases, animations. The first, The Captain's Bridge, explores shipwrecks, stormy seas, and ocean rescues. The second, The Crow's Nest, dives into the power of waves. The Deep Sea section takes users to the nether regions of the ocean, while The Weather Factory touches on cyclones, ice and icebergs, and El Nino. Additional features at the site include Ask the Expert, Facts from the Sea, an annotated collection of related sites, and information about the series.

  16. Comparative analysis of nuclear ribosomal DNA from the moon jelly Aurelia sp.1 (Cnidaria: Scyphozoa) with characterizations of the 18S, 28S genes, and the intergenic spacer (IGS)

    Microsoft Academic Search

    Jang-Seu Ki; Il-Chan Kim; Jae-Seong Lee

    Nuclear ribosomal DNAs (rDNA) constitute a multi-gene family with tandemly arranged units linked by an intergenic spacer (IGS).\\u000a Here we present the complete DNA sequence (7,731 bp) of a single repeat unit of an rDNA sequence from the moon jelly Aurelia sp.1 (Cnidaria: Scypozoa). The tandemly repeated rDNA units consisted of coding and non- coding regions, whose arrangement\\u000a was 18S

  17. Sea Ice

    NASA Technical Reports Server (NTRS)

    Perovich, D.; Gerland, S.; Hendricks, S.; Meier, Walter N.; Nicolaus, M.; Richter-Menge, J.; Tschudi, M.

    2013-01-01

    During 2013, Arctic sea ice extent remained well below normal, but the September 2013 minimum extent was substantially higher than the record-breaking minimum in 2012. Nonetheless, the minimum was still much lower than normal and the long-term trend Arctic September extent is -13.7 per decade relative to the 1981-2010 average. The less extreme conditions this year compared to 2012 were due to cooler temperatures and wind patterns that favored retention of ice through the summer. Sea ice thickness and volume remained near record-low levels, though indications are of slightly thicker ice compared to the record low of 2012.

  18. Sea Launch

    NSDL National Science Digital Library

    Sea Launch is an international satellite launch service company that has a unique way of delivering payloads into space. With the launch platform situated on the equator in the middle of the Pacific Ocean, a specially designed rocket propels satellites into orbit with very good accuracy. The Sea Launch home page has plenty of information about its operation, including an overview of the technology, statistics about its successes and failures, and Webcasts of many of its launches. A 200+ page user's guide goes into detail about all the various stages of a mission; everything from design considerations for the spacecraft to transportation to the launch site is mentioned in the document.

  19. Aral Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This series of MODIS images shows the dwindling Aral Sea. Once one of the world's largest freshwater lakes, the Aral Sea has decreased by as much as 60% over the past few decades due to diversion of the water to grow cotton and rice. These diversion have dropped the lake levels, increased salinity, and nearly decimated the fishing industry. The previous extent of the lake is clearly visible as a whitish perimeter in these image from April 16, May 18, and June 3, 2002. s. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  20. The effects of asexual reproduction and inter-genotypic aggression on the genotypic structure of populations of the sea anemone Actinia tenebrosa

    Microsoft Academic Search

    D. J. Ayre

    1983-01-01

    Genotype frequencies of adult and juvenile Actinia tenebrosa from 2 populations showed that settlement and recruitment predominantly involved the localised asexual (ameiotic) proliferation of established genotypes. However, there is strong indirect evidence that the genotypic variation was generated by sexual reproduction. Genotypic structuring of these populations was detected at 2 levels. First, coarse clumping of genotypically identical adults and juveniles

  1. Venom present in sea anemone (Heteractis magnifica) induces apoptosis in non-small-cell lung cancer A549 cells through activation of mitochondria-mediated pathway.

    PubMed

    Ramezanpour, Mahnaz; da Silva, Karen Burke; Sanderson, Barbara J S

    2014-03-01

    Lung cancer is a major cause of cancer deaths throughout the world and the complexity of apoptosis resistance in lung cancer is apparent. Venom from Heteractis magnifica caused dose-dependent decreases in survival of the human non-small-cell lung cancer cell line, as determined by the MTT and Crystal Violet assays. The H. magnifica venom induced cell cycle arrest and induced apoptosis of A549 cells, as confirmed by annexin V/propidium iodide staining. The venom-induced apoptosis in A549 cells was characterized by cleavage of caspase-3 and a reduction in the mitochondrial membrane potential. Interestingly, crude extracts from H. magnifica had less effect on the survival of non-cancer cell lines. In the non-cancer cells, the mechanism via which cell death occurred was through necrosis not apoptosis. These findings are important for future work using H. magnifica venom for pharmaceutical development to treat human lung cancer. PMID:24190482

  2. Stylobates birtlesi sp. n., a new species of carcinoecium-forming sea anemone... 33 Stylobates birtlesi sp. n., a new species of carcinoecium-

    E-print Network

    Fautin, Daphne

    , and reproduction in any medium, provided the original author and source are credited. RESEARCH ARTICLE Launched as many species of cnidarians (e.g. Williams and McDermott 2004), including hydrozoans (e.g. Millard 1975

  3. Revision of sea anemone genus *Epiactis* (Coelenterata: Actiniaria) on the Pacific coast of North America, with descriptions of two new brooding species

    E-print Network

    Fautin, Daphne G.; Chia, Fu-Shiang

    1986-01-01

    *, and its type species, *C. ritteri*, is restored to the genus in which it was originally described. Thus, four species of *Epiactis* are known on the Pacific coast of North America: external brooders *E. prolifera* (type species of the genus) and *E...

  4. Sea ice in the China Sea

    SciTech Connect

    Deng Shuqi [National Research Center for Marine Environmental Forecasts, Beijing (China)

    1993-12-31

    In every winter, sea ice occurring in Bohai Sea and the North Yellow Sea is the first-year ice which is going through generating, developing and thawing processes. Therefore, it is necessary to spatially and temporally describe ice period, freezing range, thickness variations and general motion of sea ice. The purpose of this paper is to provide initial general situation and features of sea ice for forecasting and researching sea ice.

  5. Two streptomyces species producing antibiotic, antitumor, and anti-inflammatory compounds are widespread among intertidal macroalgae and deep-sea coral reef invertebrates from the central cantabrian sea.

    PubMed

    Braña, Afredo F; Fiedler, Hans-Peter; Nava, Herminio; González, Verónica; Sarmiento-Vizcaíno, Aida; Molina, Axayacatl; Acuña, José L; García, Luis A; Blanco, Gloria

    2015-04-01

    Streptomycetes are widely distributed in the marine environment, although only a few studies on their associations to algae and coral ecosystems have been reported. Using a culture-dependent approach, we have isolated antibiotic-active Streptomyces species associated to diverse intertidal marine macroalgae (Phyllum Heterokontophyta, Rhodophyta, and Chlorophyta), from the central Cantabrian Sea. Two strains, with diverse antibiotic and cytotoxic activities, were found to inhabit these coastal environments, being widespread and persistent over a 3-year observation time frame. Based on 16S rRNA sequence analysis, the strains were identified as Streptomyces cyaneofuscatus M-27 and Streptomyces carnosus M-40. Similar isolates to these two strains were also associated to corals and other invertebrates from deep-sea coral reef ecosystem (Phyllum Cnidaria, Echinodermata, Arthropoda, Sipuncula, and Anelida) living up to 4.700-m depth in the submarine Avilés Canyon, thus revealing their barotolerant feature. These two strains were also found to colonize terrestrial lichens and have been repeatedly isolated from precipitations from tropospheric clouds. Compounds with antibiotic and cytotoxic activities produced by these strains were identified by high-performance liquid chromatography (HPLC) and database comparison. Antitumor compounds with antibacterial activities and members of the anthracycline family (daunomycin, cosmomycin B, galtamycin B), antifungals (maltophilins), anti-inflamatory molecules also with antituberculosis properties (lobophorins) were identified in this work. Many other compounds produced by the studied strains still remain unidentified, suggesting that Streptomyces associated to algae and coral ecosystems might represent an underexplored promising source for pharmaceutical drug discovery. PMID:25319239

  6. Aral Sea

    Atmospheric Science Data Center

    2013-04-16

    ... The retreating shoreline leaves the surface encrusted with salt and with agrochemicals brought in by the rivers. As the Sea's moderating ... Large Aral, and may be associated with windblown snow and/or salt particles carried aloft. The Multi-angle Imaging SpectroRadiometer ...

  7. Surficial geology of the sea floor in Long Island Sound offshore of Orient Point, New York

    USGS Publications Warehouse

    McMullen, K.Y.; Poppe, L.J.; Danforth, W.W.; Blackwood, D.S.; Schaer, J.D.; Guberski, M.R.; Wood, D.A.; Doran, E.F.

    2011-01-01

    The U.S. Geological Survey (USGS), the National Oceanic and Atmospheric Administration (NOAA), and the Connecticut Department of Environmental Protection (CT DEP) are working cooperatively to map and interpret features of the sea floor along the northeastern coast of the United States. This report presents multibeam bathymetry and sidescan-sonar data obtained during NOAA survey H11446, which was conducted in a 12-km2 area in Long Island Sound offshore of Orient Point, NY. In addition, sediment and photographic data from 26 stations obtained during a USGS verification cruise are presented. Overall, the sea floor slopes gently seaward, but topography is more complex in sand-wave and boulder areas, which are evident in the multibeam and sidescan-sonar data from the study area. Sand waves generally have north-south-oriented crests with 10- to 20-m wavelengths. Sand-wave asymmetry indicates eastward net sediment transport in the east and westward net sediment transport in the northern and western parts of the study area. Areas with boulders on the sea floor are typically hummocky and are part of a glacial moraine system. Boulders are typically encrusted with seaweed, sponges, and anemones as shown in the bottom photography.

  8. A vertical wall dominated by Acesta excavata and Neopycnodonte zibrowii, part of an undersampled group of deep-sea habitats.

    PubMed

    Johnson, Mark P; White, Martin; Wilson, Annette; Würzberg, Laura; Schwabe, Enrico; Folch, Helka; Allcock, A Louise

    2013-01-01

    We describe a novel biotope at 633 to 762 m depth on a vertical wall in the Whittard Canyon, an extensive canyon system reaching from the shelf to the deep sea on Ireland's continental margin. We explored this wall with an ROV and compiled a photomosaic of the habitat. The assemblage contributing to the biotope was dominated by large limid bivalves, Acesta excavata (mean shell height 10.4 cm), and deep-sea oysters, Neopycnodonte zibrowii, at high densities, particularly at overhangs. Mean density of N. zibrowii increased with depth, with densities of the most closely packed areas of A. excavata also increasing with depth. Other taxa associated with the assemblage included the solitary coral Desmophyllum dianthus, cerianthid anemones, comatulid crinoids, the trochid gastropod Margarites sp., the portunid crab Bathynectes longispina and small fish of the family Bythitidae. The scleractinian coral Madrepora oculata, the pencil urchin Cidaris cidaris and a species of Epizoanthus were also common. Prominent but less abundant species included the flytrap anemone Actinoscyphia saginata, the carrier crab Paramola cuvieri, and the fishes Lepidion eques and Conger conger. Observations of the hydrography of the canyon system identified that the upper 500 m was dominated by Eastern North Atlantic Water, with Mediterranean Outflow Water beneath it. The permanent thermocline is found between 600 and 1000 m depth, i.e., in the depth range of the vertical wall and the dense assemblage of filter feeders. Beam attenuation indicated nepheloid layers present in the canyon system with the greatest amounts of suspended material at the ROV dive site between 500 and 750 m. A cross-canyon CTD transect indicated the presence of internal waves between these depths. We hypothesise that internal waves concentrate suspended sediment at high concentrations at the foot of the vertical wall, possibly explaining the large size and high density of filter-feeding molluscs. PMID:24260319

  9. A Vertical Wall Dominated by Acesta excavata and Neopycnodonte zibrowii, Part of an Undersampled Group of Deep-Sea Habitats

    PubMed Central

    Johnson, Mark P.; White, Martin; Wilson, Annette; Würzberg, Laura; Schwabe, Enrico; Folch, Helka; Allcock, A. Louise

    2013-01-01

    We describe a novel biotope at 633 to 762 m depth on a vertical wall in the Whittard Canyon, an extensive canyon system reaching from the shelf to the deep sea on Ireland’s continental margin. We explored this wall with an ROV and compiled a photomosaic of the habitat. The assemblage contributing to the biotope was dominated by large limid bivalves, Acesta excavata (mean shell height 10.4 cm), and deep-sea oysters, Neopycnodonte zibrowii, at high densities, particularly at overhangs. Mean density of N. zibrowii increased with depth, with densities of the most closely packed areas of A. excavata also increasing with depth. Other taxa associated with the assemblage included the solitary coral Desmophyllum dianthus, cerianthid anemones, comatulid crinoids, the trochid gastropod Margarites sp., the portunid crab Bathynectes longispina and small fish of the family Bythitidae. The scleractinian coral Madrepora oculata, the pencil urchin Cidaris cidaris and a species of Epizoanthus were also common. Prominent but less abundant species included the flytrap anemone Actinoscyphia saginata, the carrier crab Paramola cuvieri, and the fishes Lepidion eques and Conger conger. Observations of the hydrography of the canyon system identified that the upper 500 m was dominated by Eastern North Atlantic Water, with Mediterranean Outflow Water beneath it. The permanent thermocline is found between 600 and 1000 m depth, i.e., in the depth range of the vertical wall and the dense assemblage of filter feeders. Beam attenuation indicated nepheloid layers present in the canyon system with the greatest amounts of suspended material at the ROV dive site between 500 and 750 m. A cross-canyon CTD transect indicated the presence of internal waves between these depths. We hypothesise that internal waves concentrate suspended sediment at high concentrations at the foot of the vertical wall, possibly explaining the large size and high density of filter-feeding molluscs. PMID:24260319

  10. Biomass of Scyphozoan Jellyfish, and Its Spatial Association with 0-Group Fish in the Barents Sea

    E-print Network

    Elena Eriksen; Dmitry Prozorkevich; R Trofimov; Daniel Howell

    2011-01-01

    An 0-group fish survey is conducted annually in the Barents Sea in order to estimate fish population abundance. Data on jellyfish by-catch have been recorded since 1980, although this dataset has never been analysed. In recent years, however, the ecological importance of jellyfish medusae has become widely recognized. In this paper the biomass of jellyfish (medusae) in 0–60 m depths is calculated for the period 1980–2010. During this period the climate changed from cold to warm, and changes in zooplankton and fish distribution and abundance were observed. This paper discusses the less well known ecosystem component; jellyfish medusae within the Phylum Cnidaria, and their spatial and temporal variation. The long term average was ca. 9610 8 kg, with some years showing biomasses in excess of 5610 9 kg. The biomasses were low during 1980s, increased during 1990s, and were highest in early 2000s with a subsequent decline. The bulk of the jellyfish were observed in the central parts of the Barents Sea, which is a core area for most 0-group fishes. Jellyfish were associated with haddock in the western area, with haddock and herring in the central and coastal area, and with capelin in the northern area of the Barents Sea. The jellyfish were present in the temperature interval 1uC,T,10uC, with peak densities at ca. 5.5uC, and the greatest proportion of the jellyfish occurring between 4.0–7.0uC. It seems that the ongoing warming trend may be favourable for Barents Sea jellyfish medusae; however their biomass has showed a recent moderate decline during years with record high temperatures in the Barents Sea. Jellyfish are undoubtedly an important component of the Barents

  11. Anthozoa -Corals and Anemones

    E-print Network

    Cochran-Stafira, D. Liane

    the original cnidarians all medusae and pelagic, with the medusa being lost in the anthozoans and most later? Anthozoa · Reproduction ­ Asexual · Longitudinal or transverse fission · Pedal laceration ­ Parts

  12. From Sea to Shining Sea

    ERIC Educational Resources Information Center

    Scott, Beverly

    2005-01-01

    Deep down in the depths of the sea, beautiful fish, mysterious ocean life, and unusual plants glimmer and glow in the eerie atmosphere of an ever-changing ocean. This article describes how, with this vision and a purpose in mind, three teachers pulled open classroom walls and joined forces so their second graders could create a mammoth 30 x 75"…

  13. Sea Ice

    NSDL National Science Digital Library

    In this resource, students will discover that there are notable differences between sea ice and fresh-water ice, such as density. In on segment, students learn that the first sign of freezing on the sea is an oily appearance of the water caused by the formation of needle-like crystals. The site explains the relationship between growth and the rate at which heat flows from the water and that the ice pack can alter its shape and dimension due to the movement of winds, currents, thermal expansion, and contraction of the ice. Types of ice described here include new ice, nilas, young ice, first-year ice, and old ice while the forms of ice covered include pancake ice, brash ice, ice cake, floe, and fast ice. The site also explains the meteorological and oceanographic factors that control the amount and movement of ice.

  14. Sea World

    NSDL National Science Digital Library

    Excellent resource for information and teaching activities on marine life, designed primarily for elementary level. Teachers can sign up for a monthly e-newsletter (or access archived newsletters) filled with classroom activities, current information, and special links. Also features a searchable database of Sea World education materials and information on camps, marine science careers, and Shamu TV, an award-winning series broadcast around the country via satellite and cable.

  15. Corallimorphus niwa new species (Cnidaria: Anthozoa), New Zealand members of Corallimorphus, and redefinition of Corallimorphidae and its members

    E-print Network

    Fautin, Daphne G.

    2011-02-24

    The new species of anthozoan Corallimorphus niwa occurs at depths of 926–1773 m in seas around New Zealand. This new species shares with other members of Corallimorphus stiff and hyaline mesoglea, short column relative to its broad oral disc...

  16. Reproduction of Cnidaria

    E-print Network

    Fautin, Daphne G.

    2002-01-01

    of Eucheilota paradoxica (see Carré and Carré 1990), and in Turritopsis nutricula a medusa can settle and transform entirely into tissue that gives rise to polyps (Bavestrello et al. 1992). In some species the sexual phase is brief to non-existent (e...

  17. Reproduction of Cnidaria

    Microsoft Academic Search

    Daphne Gail Fautin

    2002-01-01

    Empirical and experimental data on cnidarian reproduction show it to be more variable than had been thought, and many patterns that had previously been deduced hold up poorly or not at all in light of additional data. The border between sexual and asexual reproduction appears to be faint. This may be due to analytical tools being in- sufficiently powerful to

  18. Sea Cucumbers

    NSDL National Science Digital Library

    2009-01-01

    What reef animal comes in a rainbow of crazy colors, can throw out its innards to immobilize predators, then creep away and regrow a brand-new stomach? It’s the sea cucumber, prized as a gastronomic delight by some cultures and beginning to yield some of its secrets to scientists. Follow host Ari Daniel Shapiro from a Chinatown market to the reefs of Fiji to learn more about this amazing creature. Also included is a Learn More section that provides background information on the scientists recorded in the podcast, lessons, images, and cool facts.

  19. Mammals of the Sea.

    ERIC Educational Resources Information Center

    Naturescope, 1986

    1986-01-01

    Presents information on sea mammals, including definitions and characteristics of cetaceans, pinnipeds, and sirenians. Contains descriptions of the teaching activities "Whale Music,""Draw A Whale to Scale,""Adopt a Sea Mammal," and "Sea Mammal Sleuths." (TW)

  20. Tracking Sea Otters

    USGS Multimedia Gallery

    USGS sea otter researcher Tim Tinker drives the boat on an expedition to track and observe sea otters in Monterey Bay, California. USGS scientists study sea otters in efforts to help the threatened species continue to recover from near extinction....

  1. Studying Sea Otters

    USGS Multimedia Gallery

    Sea otter researcher Michelle Staedler, of the Monterey Bay Aquarium, records sea otter behavior in her logbook as part of a study with the USGS and the University of California at Santa Cruz on sea otter behavior. ...

  2. Sea Ice

    NASA Technical Reports Server (NTRS)

    Parkinson, Claire L.; Cavalieri, Donald J.

    2005-01-01

    Sea ice covers vast areas of the polar oceans, with ice extent in the Northern Hemisphere ranging from approximately 7 x 10(exp 6) sq km in September to approximately 15 x 10(exp 6) sq km in March and ice extent in the Southern Hemisphere ranging from approximately 3 x 10(exp 6) sq km in February to approximately 18 x 10(exp 6) sq km in September. These ice covers have major impacts on the atmosphere, oceans, and ecosystems of the polar regions, and so as changes occur in them there are potential widespread consequences. Satellite data reveal considerable interannual variability in both polar sea ice covers, and many studies suggest possible connections between the ice and various oscillations within the climate system, such as the Arctic Oscillation, North Atlantic Oscillation, and Antarctic Oscillation, or Southern Annular Mode. Nonetheless, statistically significant long-term trends are also apparent, including overall trends of decreased ice coverage in the Arctic and increased ice coverage in the Antarctic from late 1978 through the end of 2003, with the Antarctic ice increases following marked decreases in the Antarctic ice during the 1970s. For a detailed picture of the seasonally varying ice cover at the start of the 21st century, this chapter includes ice concentration maps for each month of 2001 for both the Arctic and the Antarctic, as well as an overview of what the satellite record has revealed about the two polar ice covers from the 1970s through 2003.

  3. Raddeanin A, a triterpenoid saponin isolated from Anemone raddeana, suppresses the angiogenesis and growth of human colorectal tumor by inhibiting VEGFR2 signaling.

    PubMed

    Guan, Ying-Yun; Liu, Hai-Jun; Luan, Xin; Xu, Jian-Rong; Lu, Qin; Liu, Ya-Rong; Gao, Yun-Ge; Zhao, Mei; Chen, Hong-Zhuan; Fang, Chao

    2015-01-15

    Raddeanin A (RA) is an active triterpenoid saponin from a traditional Chinese medicinal herb, Anemone raddeana Regel. It was previously reported that RA possessed attractive antitumor activity through inhibiting proliferation and inducing apoptosis of multiple cancer cells. However, whether RA can inhibit angiogenesis, an essential step in cancer development, remains unknown. In this study, we found that RA could significantly inhibit human umbilical vein endothelial cell (HUVEC) proliferation, motility, migration, and tube formation. RA also dramatically reduced angiogenesis in chick embryo chorioallantoic membrane (CAM), restrained the trunk angiogenesis in zebrafish, and suppressed angiogenesis and growth of human HCT-15 colorectal cancer xenograft in mice. Western blot assay showed that RA suppressed VEGF-induced phosphorylation of VEGFR2 and its downstream protein kinases including PLC?1, JAK2, FAK, Src, and Akt. Molecular docking simulation indicated that RA formed hydrogen bonds and hydrophobic interactions within the ATP binding pocket of VEGFR2 kinase domain. Our study firstly provides the evidence that RA has high antiangiogenic potency and explores its molecular basis, demonstrating that RA is a potential agent or lead candidate for antiangiogenic cancer therapy. PMID:25636878

  4. Natural Selection and Neutral Evolution Jointly Drive Population Divergence between Alpine and Lowland Ecotypes of the Allopolyploid Plant Anemone multifida (Ranunculaceae)

    PubMed Central

    McEwen, Jamie R.; Vamosi, Jana C.; Rogers, Sean M.

    2013-01-01

    Population differentiation can be driven in large part by natural selection, but selectively neutral evolution can play a prominent role in shaping patters of population divergence. The decomposition of the evolutionary history of populations into the relative effects of natural selection and selectively neutral evolution enables an understanding of the causes of population divergence and adaptation. In this study, we examined heterogeneous genomic divergence between alpine and lowland ecotypes of the allopolyploid plant, Anemone multifida. Using peak height and dominant AFLP data, we quantified population differentiation at non-outlier (neutral) and outlier loci to determine the potential contribution of natural selection and selectively neutral evolution to population divergence. We found 13 candidate loci, corresponding to 2.7% of loci, with signatures of divergent natural selection between alpine and lowland populations and between alpine populations (Fst ?=?0.074–0.445 at outlier loci), but neutral population differentiation was also evident between alpine populations (FST ?=?0.041–0.095 at neutral loci). By examining population structure at both neutral and outlier loci, we determined that the combined effects of selection and neutral evolution are associated with the divergence of alpine populations, which may be linked to extreme abiotic conditions and isolation between alpine sites. The presence of outlier levels of genetic variation in structured populations underscores the importance of separately analyzing neutral and outlier loci to infer the relative role of divergent natural selection and neutral evolution in population divergence. PMID:23874801

  5. Self/nonself recognition in Cnidaria: contact to allogeneic tissue does not result in elimination of nonself cells in Hydra vulgaris.

    PubMed

    Kuznetsov, Sergey G; Bosch, Thomas C G

    2003-01-01

    Although Cnidaria have no specialised immune cells, some colonial forms possess a genetic system to discriminate between self and nonself. Allorecognition is thought to protect them from fusion with genetically different individuals and to prevent germ line parasitism. Surprisingly, when grafting tissue of two species of the solitary freshwater polyp Hydra, we found within the contact zone phagocytozing epithelial cells which selectively eliminated cells from the other species (Bosch and David, 1986). This led us to speculate that Hydra, which never undergoes "natural transplantation", can differentiate between self and nonself (Bosch and David, 1986). In a previous paper (Kuznetsov et al., 2002) we described that cells which accumulate in the contact region of these interspecies grafts are apoptotic and that apoptosis is induced by impaired cell matrix contact. Thus, observations in such interspecies grafts did not give hints concerning the presence of a discriminative allorecognition system. To clarify whether this fundamental aspect of immunity is present in these phylogenetically old animals, we examined epithelial interactions between different strains of Hydra vulgaris. Here, we show that contact to allogeneic tissue does not evoke any response in terms of phagocytosis and elimination of allogeneic cells. We, therefore, question Hydra's ability to discriminate between self and nonself and propose that, in contrast to colonial cnidarians, the solitary polyp Hydra has either lost or substantially reduced this ability. PMID:16351896

  6. California Sea Grant 1 California Sea Grant

    E-print Network

    Jaffe, Jules

    California Sea Grant 1 California Sea Grant Strategic Plan 2010­2013 #12;2 Strategic Plan 2010­2013 The National Sea Grant College Program, U.S. Department of Commerce, National Oceanic and Atmospheric Administration, supported this publication under NOAA grant number NA08OAR4170669, project number C/P-1 through

  7. Climate-mediated changes in zooplankton community structure for the eastern Bering Sea

    NASA Astrophysics Data System (ADS)

    Eisner, Lisa B.; Napp, Jeffrey M.; Mier, Kathryn L.; Pinchuk, Alexei I.; Andrews, Alexander G.

    2014-11-01

    Zooplankton are critical to energy transfer between higher and lower trophic levels in the eastern Bering Sea ecosystem. Previous studies from the southeastern Bering Sea shelf documented substantial differences in zooplankton taxa in the Middle and Inner Shelf Domains between warm and cold years. Our investigation expands this analysis into the northern Bering Sea and the south Outer Domain, looking at zooplankton community structure during a period of climate-mediated, large-scale change. Elevated air temperatures in the early 2000s resulted in regional warming and low sea-ice extent in the southern shelf whereas the late 2000s were characterized by cold winters, extensive spring sea ice, and a well-developed pool of cold water over the entire Middle Domain. The abundance of large zooplankton taxa such as Calanus spp. (C. marshallae and C. glacialis), and Parasagitta elegans, increased from warm to cold periods, while the abundance of gelatinous zooplankton (Cnidaria) and small taxa decreased. Biomass followed the same trends as abundance, except that the biomass of small taxa in the southeastern Bering Sea remained constant due to changes in abundance of small copepod taxa (increases in Acartia spp. and Pseudocalanus spp. and decreases in Oithona spp.). Statistically significant changes in zooplankton community structure and individual species were greatest in the Middle Domain, but were evident in all shelf domains, and in both the northern and southern portions of the eastern shelf. Changes in community structure did not occur abruptly during the transition from warm to cold, but seemed to begin gradually and build as the influence of the sea ice and cold water temperatures persisted. The change occurred one year earlier in the northern than the southern Middle Shelf. These and previous observations demonstrate that lower trophic levels within the eastern Bering Sea respond to climate-mediated changes on a variety of time scales, including those shorter than the commonly accepted quasi-decadal time periods. This lack of resilience or inertia at the lowest trophic levels affects production at higher trophic levels and must be considered in management strategy evaluations of living marine resources.

  8. Surficial geology of the sea floor in Central Rhode Island Sound Southeast of Point Judith, Rhode Island

    USGS Publications Warehouse

    McMullen, K.Y.; Poppe, L.J.; Ackerman, S.D.; Blackwood, D.S.; Schaer, J.D.; Nadeau, M.A.; Wood, D.A.

    2011-01-01

    The U.S. Geological Survey (USGS) and the National Oceanic and Atmospheric Administration (NOAA) are working together to study sea-floor environments off the northeast coast of the United States. During 2008, NOAA survey H11996 collected multibeam echosounder data in a 65-square kilometer area in central Rhode Island Sound, southeast of Point Judith, Rhode Island. During 2010, the USGS collected bottom photographs and sediment samples from 25 stations in this study area. The bathymetry, photography, and sediment data are used to interpret sea-floor features including scour depressions, sand waves, trawl marks, and dredge spoils. Scour depressions cover the bathymetric highs in much of the study area. Sand waves are located mostly in the southwest, and trawl marks tend to be in the northern regions. Dredge spoils are located at a disposal site in a bathymetric low in the western end of the study area. Most stations have a sea-floor surface of sand or silty sand, but eight of the stations have boulders to pea-sized gravel or gravelly sediment on the surface. Photographs show sandy areas typically have scattered burrows, shells, amphipod communities, and worm tubes. Boulders and cobbles are commonly overgrown with hydrozoans and anemones.

  9. Mini-review: the evolution of neuropeptide signaling.

    PubMed

    Grimmelikhuijzen, Cornelis J P; Hauser, Frank

    2012-08-10

    Neuropeptides and their G protein-coupled receptors (GPCRs) have an early evolutionary origin and are already abundant in basal animals with primitive nervous systems such as cnidarians (Hydra, jellyfishes, corals, and sea anemones). Most animals emerging after the Cnidaria belong to two evolutionary lineages, the Protostomia (to which the majority of invertebrates belong) and Deuterostomia (to which some minor groups of invertebrates, and all vertebrates belong). These two lineages split about 700 million years (Myr) ago. Many mammalian neuropeptide GPCRs have orthologues in the Protostomia and this is also true for some of the mammalian neuropeptides. Examples are oxytocin/vasopressin, GnRH, gastrin/CCK, and neuropeptide Y and their GPCRs. These results implicate that protostomes (for example insects and nematodes) can be used as models to study the biology of neuropeptide signaling. PMID:22726357

  10. The Discovery of New Deep-Sea Hydrothermal Vent Communities in the Southern Ocean and Implications for Biogeography

    PubMed Central

    Rogers, Alex D.; Tyler, Paul A.; Connelly, Douglas P.; Copley, Jon T.; James, Rachael; Larter, Robert D.; Linse, Katrin; Mills, Rachel A.; Garabato, Alfredo Naveira; Pancost, Richard D.; Pearce, David A.; Polunin, Nicholas V. C.; German, Christopher R.; Shank, Timothy; Boersch-Supan, Philipp H.; Alker, Belinda J.; Aquilina, Alfred; Bennett, Sarah A.; Clarke, Andrew; Dinley, Robert J. J.; Graham, Alastair G. C.; Green, Darryl R. H.; Hawkes, Jeffrey A.; Hepburn, Laura; Hilario, Ana; Huvenne, Veerle A. I.; Marsh, Leigh; Ramirez-Llodra, Eva; Reid, William D. K.; Roterman, Christopher N.; Sweeting, Christopher J.; Thatje, Sven; Zwirglmaier, Katrin

    2012-01-01

    Since the first discovery of deep-sea hydrothermal vents along the Galápagos Rift in 1977, numerous vent sites and endemic faunal assemblages have been found along mid-ocean ridges and back-arc basins at low to mid latitudes. These discoveries have suggested the existence of separate biogeographic provinces in the Atlantic and the North West Pacific, the existence of a province including the South West Pacific and Indian Ocean, and a separation of the North East Pacific, North East Pacific Rise, and South East Pacific Rise. The Southern Ocean is known to be a region of high deep-sea species diversity and centre of origin for the global deep-sea fauna. It has also been proposed as a gateway connecting hydrothermal vents in different oceans but is little explored because of extreme conditions. Since 2009 we have explored two segments of the East Scotia Ridge (ESR) in the Southern Ocean using a remotely operated vehicle. In each segment we located deep-sea hydrothermal vents hosting high-temperature black smokers up to 382.8°C and diffuse venting. The chemosynthetic ecosystems hosted by these vents are dominated by a new yeti crab (Kiwa n. sp.), stalked barnacles, limpets, peltospiroid gastropods, anemones, and a predatory sea star. Taxa abundant in vent ecosystems in other oceans, including polychaete worms (Siboglinidae), bathymodiolid mussels, and alvinocaridid shrimps, are absent from the ESR vents. These groups, except the Siboglinidae, possess planktotrophic larvae, rare in Antarctic marine invertebrates, suggesting that the environmental conditions of the Southern Ocean may act as a dispersal filter for vent taxa. Evidence from the distinctive fauna, the unique community structure, and multivariate analyses suggest that the Antarctic vent ecosystems represent a new vent biogeographic province. However, multivariate analyses of species present at the ESR and at other deep-sea hydrothermal vents globally indicate that vent biogeography is more complex than previously recognised. PMID:22235194

  11. The discovery of new deep-sea hydrothermal vent communities in the southern ocean and implications for biogeography.

    PubMed

    Rogers, Alex D; Tyler, Paul A; Connelly, Douglas P; Copley, Jon T; James, Rachael; Larter, Robert D; Linse, Katrin; Mills, Rachel A; Garabato, Alfredo Naveira; Pancost, Richard D; Pearce, David A; Polunin, Nicholas V C; German, Christopher R; Shank, Timothy; Boersch-Supan, Philipp H; Alker, Belinda J; Aquilina, Alfred; Bennett, Sarah A; Clarke, Andrew; Dinley, Robert J J; Graham, Alastair G C; Green, Darryl R H; Hawkes, Jeffrey A; Hepburn, Laura; Hilario, Ana; Huvenne, Veerle A I; Marsh, Leigh; Ramirez-Llodra, Eva; Reid, William D K; Roterman, Christopher N; Sweeting, Christopher J; Thatje, Sven; Zwirglmaier, Katrin

    2012-01-01

    Since the first discovery of deep-sea hydrothermal vents along the Galápagos Rift in 1977, numerous vent sites and endemic faunal assemblages have been found along mid-ocean ridges and back-arc basins at low to mid latitudes. These discoveries have suggested the existence of separate biogeographic provinces in the Atlantic and the North West Pacific, the existence of a province including the South West Pacific and Indian Ocean, and a separation of the North East Pacific, North East Pacific Rise, and South East Pacific Rise. The Southern Ocean is known to be a region of high deep-sea species diversity and centre of origin for the global deep-sea fauna. It has also been proposed as a gateway connecting hydrothermal vents in different oceans but is little explored because of extreme conditions. Since 2009 we have explored two segments of the East Scotia Ridge (ESR) in the Southern Ocean using a remotely operated vehicle. In each segment we located deep-sea hydrothermal vents hosting high-temperature black smokers up to 382.8°C and diffuse venting. The chemosynthetic ecosystems hosted by these vents are dominated by a new yeti crab (Kiwa n. sp.), stalked barnacles, limpets, peltospiroid gastropods, anemones, and a predatory sea star. Taxa abundant in vent ecosystems in other oceans, including polychaete worms (Siboglinidae), bathymodiolid mussels, and alvinocaridid shrimps, are absent from the ESR vents. These groups, except the Siboglinidae, possess planktotrophic larvae, rare in Antarctic marine invertebrates, suggesting that the environmental conditions of the Southern Ocean may act as a dispersal filter for vent taxa. Evidence from the distinctive fauna, the unique community structure, and multivariate analyses suggest that the Antarctic vent ecosystems represent a new vent biogeographic province. However, multivariate analyses of species present at the ESR and at other deep-sea hydrothermal vents globally indicate that vent biogeography is more complex than previously recognised. PMID:22235194

  12. Diversity, Distribution and Nature of Faunal Associations with Deep-Sea Pennatulacean Corals in the Northwest Atlantic

    PubMed Central

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

    2014-01-01

    Anthoptilum grandiflorum and Halipteris finmarchica are two deep-sea corals (Octocorallia: Pennatulacea) common on soft bottoms in the North Atlantic where they are believed to act as biogenic habitat. The former also has a worldwide distribution. To assist conservation efforts, this study examines spatial and temporal patterns in the abundance, diversity, and nature of their faunal associates. A total of 14 species were found on A. grandiflorum and 6 species on H. finmarchica during a multi-year and multi-site sampling campaign in eastern Canada. Among those, 7 and 5 species, respectively, were attached to the sea pens and categorized as close associates or symbionts. Rarefaction analyses suggest that the most common associates of both sea pens have been sampled. Biodiversity associated with each sea pen is analyzed according to season, depth and region using either close associates or the broader collection of species. Associated biodiversity generally increases from northern to southern locations and does not vary with depth (?100–1400 m). Seasonal patterns in A. grandiflorum show higher biodiversity during spring/summer due to the transient presence of early life stages of fishes and shrimps whereas it peaks in fall for H. finmarchica. Two distinct endoparasitic species of highly modified copepods (families Lamippidae and Corallovexiidae) commonly occur in the polyps of A. grandiflorum and H. finmarchica, and a commensal sea anemone frequently associates with H. finmarchica. Stable isotope analyses (?13C and ?15N) reveal potential trophic interactions between the parasites and their hosts. Overall, the diversity of obligate/permanent associates of sea pens is moderate; however the presence of mobile/transient associates highlights an ecological role that has yet to be fully elucidated and supports their key contribution to the enhancement of biodiversity in the Northwest Atlantic. PMID:25369515

  13. Colorful Underwater Sea Creatures

    ERIC Educational Resources Information Center

    McCutcheon, Heather

    2011-01-01

    In this article, the author describes a project wherein students created colorful underwater sea creatures. This project began with a discussion about underwater sea creatures and how they live. The first step was making the multi-colored tissue paper that would become sea creatures and seaweed. Once students had the shapes of their sea creatures…

  14. Beaufort Sea: information update

    SciTech Connect

    Becker, P.R.

    1988-04-01

    The report is based on a multi-disciplinary meeting held March 6-7, 1985, as part of preparations for the Beaufort Sea Sale 97. The chapters are based on presentations given: The causeway effect: Modification of nearshore thermal regime resulting from causeways; Summertime sea ice intrusions in the Chukchi Sea; The deepwater limit of ice gouging on the Beaufort Sea shelf; Distribution, abundance, migration, harvest, and stock identity of Belukha Whales in the Beaufort Sea; Ringed seals in the Beaufort Sea; Beaufort Sea socioeconomics; The Baffin Island Oil Spill, (BIOS) Project.

  15. New taxa and revisionary systematics of alcyonacean octocorals from the Pacific coast of North America (Cnidaria, Anthozoa)

    PubMed Central

    Williams, Gary C.

    2013-01-01

    Abstract A taxonomic assessment of four species of octocorals from the northeastern Pacific Ocean (British Columbia to California) is provided. Included here are a new species of clavulariid stolonifieran Cryptophyton, a new species of the nephtheid soft coral Gersemia, an undetermined species of soft coral in the genus Alcyonium that has been referred in the literature by several other names, and a new genus is named for a plexaurid sea fan originally described in the Indo-Pacific genus Euplexaura. Discussions are included that compare the species to related taxa, or provide revisionary assessments. PMID:23794840

  16. Benthic meiofaunal composition and community structure in the Sethukuda mangrove area and adjacent open sea, East coast of India

    NASA Astrophysics Data System (ADS)

    Thilagavathi, Balasubramanaian; Das, Bandana; Saravanakumar, Ayyappan; Raja, Kuzhanthaivel

    2011-06-01

    The ecological aspects of meiofaunal communities in the Muthupettai mangrove forest, East coast of India, has not been investigated in the last two decades. Surface water temperature ranged from 23.5 °C to 31.8 °C. Salinity varied from 24 to 34 ppt, while water pH fluctuated from 7.4 to 8.3. Dissolved oxygen concentration ranged from 3.86 to 5.33 mg/l. Meiofauna analysis in this study identified a total of 106 species from the mangrove and adjacent open sea area of Sethukuda. Among these, 56 species of foraminiferans, 20 species of nematodes, 7 species of harpacticoid copepods, 4 species of ostrocodes, and 2 species of rotifers were identified. Furthermore, a single species was identified from the following groups: ciliophora, cnidaria, gnathostomulida, insecta, propulida, bryozoa and polychaete larvae. Meiofaunal density varied between 12029 to 23493 individuals 10 cm/m2. The diversity index ranged from 3.515 to 3.680, species richness index varied from 6.384 to 8.497, and evenness index varied from 0.839 to 0876 in the mangrove area and adjacent open sea.

  17. Metazoan meiofauna in deep-sea canyons and adjacent open slopes: A large-scale comparison with focus on the rare taxa

    NASA Astrophysics Data System (ADS)

    Bianchelli, S.; Gambi, C.; Zeppilli, D.; Danovaro, R.

    2010-03-01

    Metazoan meiofaunal abundance, total biomass, nematode size and the richness of taxa were investigated along bathymetric gradients (from the shelf break down to ca. 5000-m depth) in six submarine canyons and on five adjacent open slopes of three deep-sea regions. The investigated areas were distributed along >2500 km, on the Portuguese to the Catalan and South Adriatic margins. The Portuguese and Catalan margins displayed the highest abundances, biomass and richness of taxa, while the lowest values were observed in the Central Mediterranean Sea. The comparison between canyons and the nearby open slopes showed the lack of significant differences in terms of meiofaunal abundance and biomass at any sampling depth. In most canyons and on most slopes, meiofaunal variables did not display consistent bathymetric patterns. Conversely, we found that the different topographic features were apparently responsible for significant differences in the abundance and distribution of the rare meiofaunal taxa (i.e. taxa accounting for <1% of total meiofaunal abundance). Several taxa belonging to the temporary meiofauna, such as larvae/juveniles of Priapulida, Holothuroidea, Ascidiacea and Cnidaria, were encountered exclusively on open slopes, while others (including the Tanaidacea and Echinodea larvae) were found exclusively in canyons sediments. Results reported here indicate that, at large spatial scales, differences in deep-sea meiofaunal abundance and biomass are not only controlled by the available food sources, but also by the region or habitat specific topographic features, which apparently play a key role in the distribution of rare benthic taxa.

  18. Aiptasia pulchella: a tropical cnidarian representative for laboratory ecotoxicological research.

    PubMed

    Howe, Pelli Louise; Reichelt-Brushett, Amanda Jean; Clark, Malcolm William

    2012-11-01

    An urgent need exists to identify suitable tropical marine species for use in the development of sensitive and reliable test methods for routine laboratory ecotoxicological testing. Corals are a group of organisms not represented in routine ecotoxicology due to inherent difficulties in laboratory husbandry, and sea anemones from the same phylum (cnidaria) may be useful proxies. Aiptasia pulchella is a tropical symbiotic sea anemone with a wide geographic range. It is well suited to laboratory conditions and has been used extensively in research. However, its suitability as a toxicity test species has not been investigated. Assessment of juvenile recruitment in laboratory and semi-outdoor conditions showed higher production in semi-outdoor conditions; however, laboratory rearing produced enough recruits to run routine toxicity tests. In investigations of the sensitivity of A. pulchella to contaminants, acute tests were conducted on 1- to 2-mm juveniles using copper. Lethal concentration, 50% (LC50) values at 96 h estimated from tests using five and 10 replicates ranged from 30 to 83 and 60 to 90 µg/L, respectively, and a 28-d LC50 of 26 µg/L was estimated. During the present study, sublethal endpoints were investigated; chronic assessment of inhibited asexual reproduction looks promising (12-d effective concentration, 50% [EC50] 15 µg/L) and should be assessed further. Aiptasia pulchella is a species worthy of investigation as a cnidarian representative, and will be an invaluable contribution to tropical marine ecotoxicologists. PMID:22927090

  19. Tree litter and forest understorey vegetation: a conceptual framework to understand the effects of tree litter on a perennial geophyte, Anemone nemorosa

    PubMed Central

    Baltzinger, Marie; Archaux, Frédéric; Dumas, Yann

    2012-01-01

    Background and Aims Litter is a key factor in structuring plant populations, through positive or negative interactions. The litter layer forms a mechanical barrier that is often strongly selective against individuals lacking hypocotyle plasticity. Litter composition also interacts with plant growth by providing beneficial nutrients or, inversely, by allowing harmful allelopathic leaching. As conspicuous litter fall accumulation is often observed under deciduous forests, interactions between tree litter and understorey plant populations are worthy of study. Methods In a 1-year ex-situ experiment, the effects of tree litter on the growth of Anemone nemorosa, a small perennial forest geophyte, were investigated. Three ‘litter quantity’ treatments were defined, representative of forest floor litter (199, 356·5 and 514 g m?2), which were crossed with five ‘litter composition’ treatments (Quercus petraea, Fagus sylvatica, Carpinus betulus, Q. petraea + F. sylvatica and Q. petraea + C. betulus), plus a no-litter control. Path analysis was then used to investigate the pathways linking litter characteristics and components of adult plant growth. Key Results As expected, the heavier the litter, the longer the petiole; rhizome growth, however, was not depreciated by the litter-induced petiole lengthening. Both rhizome mass increment and number of initiated buds marginally increased with the amount of litter. Rhizome mass increment was in fact determined primarily by leaf area and leaf life span, neither of which was unequivocally correlated with any litter characteristics. However, the presence of litter significantly increased leafing success: following a late frost event, control rhizomes growing in the absence of litter experienced higher leaf mortality before leaf unfolding. Conclusions The study questions the role of litter as a physical or chemical barrier to ground vegetation; to better understand this role, there is a need for ex-situ, longer-term experiments coupled with in-situ observations in the forest. PMID:22419760

  20. NUMERICAL INVESTIGATION OF A CORONAL MASS EJECTION FROM AN ANEMONE ACTIVE REGION: RECONNECTION AND DEFLECTION OF THE 2005 AUGUST 22 ERUPTION

    SciTech Connect

    Lugaz, N.; Shibata, K. [Kwasan Observatory, Kyoto University, Kyoto (Japan); Downs, C.; Roussev, I. I. [Institute for Astronomy, University of Hawaii, Honolulu, HI (United States); Asai, A. [Unit of Synergetic Studies for Space, Kyoto University, Kyoto (Japan); Gombosi, T. I. [Center for Space Environment Modeling, University of Michigan, MI (United States)

    2011-09-10

    We present a numerical investigation of the coronal evolution of a coronal mass ejection (CME) on 2005 August 22 using a three-dimensional thermodynamic magnetohydrodynamic model, the space weather modeling framework. The source region of the eruption was anemone active region (AR) 10798, which emerged inside a coronal hole. We validate our modeled corona by producing synthetic extreme-ultraviolet (EUV) images, which we compare to EIT images. We initiate the CME with an out-of-equilibrium flux rope with an orientation and chirality chosen in agreement with observations of an H{alpha} filament. During the eruption, one footpoint of the flux rope reconnects with streamer magnetic field lines and with open field lines from the adjacent coronal hole. It yields an eruption which has a mix of closed and open twisted field lines due to interchange reconnection and only one footpoint line-tied to the source region. Even with the large-scale reconnection, we find no evidence of strong rotation of the CME as it propagates. We study the CME deflection and find that the effect of the Lorentz force is a deflection of the CME by about 3{sup 0} R{sup -1}{sub sun} toward the east during the first 30 minutes of the propagation. We also produce coronagraphic and EUV images of the CME, which we compare with real images, identifying a dimming region associated with the reconnection process. We discuss the implication of our results for the arrival at Earth of CMEs originating from the limb and for models to explain the presence of open field lines in magnetic clouds.

  1. Sea Turtle Conservancy

    NSDL National Science Digital Library

    The Caribbean Conservation Corporation (CCC) was founded in 1959 by sea turtle champions such as ecologist Dr. Archie Carr, who served as the CCC's Scientific Director for nearly three decades. As the oldest sea turtle organization on the globe, the CCC "works to enact protective laws and establish refuges for the preservation of sea turtle habitats and coastal environments." The CCC created the Sea Turtle Survival League (STSL) in 1993 "as a public education and advocacy program to begin addressing the threats that face U.S. sea turtle populations." The CCC & STSL website contains information about a number of sea turtle programs and projects, tracking sea turtles, different sea turtle species, and ways to become a sea turtle conservationist. CCC also offers a public discussion board, a variety of downloadable publications (including activities for kids), and a collection of related links.

  2. Syst. Biol. 54(6):916935, 2005 Copyright c Society of Systematic Biologists

    E-print Network

    Dunn, Casey

    / 1076-836X online DOI: 10.1080/10635150500354837 Molecular Phylogenetics of the Siphonophora (Cnidaria@hawaii.edu Abstract.-- Siphonophores are a group of pelagic colonial hydrozoans (Cnidaria) that have long been of short-stemmed taxa, are polyphyletic. [Cnidaria; colonial animals; deep sea; division of labor

  3. Origins of Bilateral Symmetry: Hox and Dpp Expression

    E-print Network

    Finnerty, John R.

    of bilateral symmetry. Although animals of the phylum Cnidaria are not within the Bilateria, some arose before the evolutionary split of Cnidaria and Bilateria. The Bilateria is an evolutionary lineage is the phylum Cnidaria (sea anem- ones, corals, hydras, and jellyfishes). Mod- ern cnidarians resemble

  4. Sea Surface Temperatures

    NSDL National Science Digital Library

    1999-10-30

    Users can search for and view sea surface temperature imagery. They may choose from the latest image, or browse archived imagery that dates back approximately two weeks. Links to other sea surface temperature datasets are included.

  5. Sea Turtle Populations

    NSDL National Science Digital Library

    Twin Cities Public Television, Inc.

    2007-01-01

    In this activity, learners will model how a sea turtle population changes over time, from eggs to adults, using puffed rice. Learners create a chart, calculate population fluctuation for each transitional stage of sea turtles' lives, and graph the population at each stage. Learners investigate different factors including migration and human fishing that affect the size of the sea turtle population. Relates to the linked video, DragonflyTV GPS: Sea Turtles.

  6. Sea Education Association

    NSDL National Science Digital Library

    Headquartered in Woods Hole, Massachusetts, SEA offers a variety of science programs at sea for high school and college students. Site features information on the vessels, the crew, current voyages, admissions information, and a wealth of photographs from past expeditions. Also includes a section where you can track the progress of the SEA boats and hear daily, and archived, audio reports.

  7. Tracking Sea Otters

    USGS Multimedia Gallery

    Sea otter researchers Michelle Staedler, Monterey Bay Aquarium, and Tim Tinker, USGS, work together to locate sea otters in their study project. USGS scientists and their partners study sea otters in efforts to help the threatened species continue to recover from near extinction....

  8. Alaska: Beaufort Sea

    Atmospheric Science Data Center

    2014-05-15

    ... Imaging SpectroRadiometer (MISR), illustrate different methods that may be used to assess sea ice type. Sea ice in the Beaufort Sea ... scattering. The MISR map at right was generated using a statistical classification routine (called ISODATA) and analyzed using ice ...

  9. All That Unplowed Sea

    ERIC Educational Resources Information Center

    MOSAIC, 1975

    1975-01-01

    Hunting and gathering at sea may fast be approaching their productive limits. Aquaculture - farming at sea - linked to conservation represents the sea's promise. If the system works, it might prove to be the key to supplying large amounts of food and fresh water at no cost in nonrenewable energy resources. (BT)

  10. Deep-Sea Technology

    NSDL National Science Digital Library

    In this lesson plan students will learn about special vehicles used in recent Black Sea research and the theory that the Black Sea during the Ice Age was an isolated freshwater lake surrounded by farmland that was eventually flooded. Students will describe the purpose of the research vehicles by writing newspaper articles pretending they have just returned from the Black Sea expedition.

  11. Sea Level Rise

    NSDL National Science Digital Library

    Geophysical Institute of University of Fairbanks

    In this activity, students will learn the difference between sea ice and glaciers in relation to sea level rise. They will create and explore topographic maps as a means of studying sea level rise and how it will affect Alaska's coastline.

  12. The non-Siphonophoran Hydrozoa (Cnidaria) of Salento, Italy with notes on their life-cycles: an illustrated guide.

    PubMed

    Gravili, Cinzia; Vito, Doris De; Camillo, Cristina Gioia Di; Martell, Luis; Piraino, Stefano; Boero, Ferdinando

    2015-01-01

    The majority of Hydrozoa is represented by not readily noticeable, small species. In recent decades, however, taxonomic knowledge of the group has increased worldwide, with a significant number of investigations focused on the Mediterranean Sea. Over more than two decades, 115 species of hydrozoans were recorded from coastal waters along nearly 300 km of the Salento Peninsula (Apulia, Italy). For each species, records from different collections were merged into single sheets of a general database.        For each species, the following information is reported: description, cnidome, biology, occurrence in Salento, worldwide distribution, and bibliography. Descriptions refer to the benthic hydroid stage and, when present, also to the planktonic medusa stage. The 115 species of Hydrozoa, recorded along the Salento coastline, represent 25% of the Mediterranean Hydrozoa fauna (totaling 461 species), and nearly 3% of 3,702 world's known species covered in a recent monograph. Four species are non-indigenous, three of them with invasive behavior (Clytia hummelincki, Clytia linearis, and Eudendrium carneum), and one species now very common (Eudendrium merulum) in Salento. The complete life cycle of Clytia paulensis (Vanhöffen, 1910) is described for the first time.  PMID:25661429

  13. Calibration of stable oxygen isotopes in Siderastrea radians (Cnidaria:Scleractinia): Implications for slow-growing corals

    NASA Astrophysics Data System (ADS)

    Moses, Christopher S.; Swart, Peter K.; Dodge, Richard E.

    2006-09-01

    Geochemical proxies in the skeletons of corals used for the purpose of reconstructing environmental records have typically been obtained from relatively fast-growing corals (usually >8 mm yr-1) and from only a few key genera (most commonly Porites and Montastraea). In many areas, however, there are no suitable fast-growing corals available for such reconstructions. Here, we investigate the potential of Siderastrea radians, a slow-growing Atlantic and Caribbean zooxanthellate coral, as an archive of sea surface temperature (SST) and salinity over the period from 1891 to 2002. Sampling the skeleton of three corals from the Cape Verde Islands, we were able to reproduce a clear seasonal signal, but with limited correlation to monthly SST, arising from inadequate chronologic constraint of the individual samples. The SST-?18O calibration slopes for different sampling scales on several cores can range from about -9°C ‰-1 to +2°C ‰-1 (compared to other published values of around -5 to -4°C ‰-1). Careful treatment produced a ?18O-SST calibration equation where SST(°C) = 12.56(±1.20) - 3.86(±0.39)*(?c-?w). The recognition of the limitations of calibration at such small growth rates due to skeletal complexity and suspicion of environmental interferences suggests the need for careful consideration in the interpretation of climate proxy results from S. radians and other slow-growing corals.

  14. Sea-floor geology in central Rhode Island Sound south of Sakonnet Point, Rhode Island

    USGS Publications Warehouse

    McMullen, K.Y.; Poppe, L.J.; Ackerman, S.D.; Worley, C.R.; Nadeau, M.A.; Van Hoy, M. V.

    2012-01-01

    The U.S. Geological Survey (USGS) and the National Oceanic and Atmospheric Administration (NOAA) are working together to study the sea floor along the northeastern coast of the United States. NOAA collected multibeam-echosounder data during hydrographic survey H11995 in a 63-square-kilometer area in central Rhode Island Sound, south of Sakonnet Point, Rhode Island. The USGS collected sediment samples, bottom video, and still photographs from 27 stations in this study area to verify an interpretation of the bathymetric data. Collected data are used to map areas of scour depressions and erosional outliers, megaripples, boulders, and relatively undisturbed modern marine sediments. In general, much of the eastern part of the study area, a submerged segment of the Harbor Hill-Roanoke Point-Charlestown-Buzzards Bay moraine, is bouldery. Bottom photography shows boulders are generally encrusted with hydrozoans, algae, and anemone. Scour depressions, presumably formed by long-period storm waves, and erosional outliers of Holocene sediments dominate the western part of the study area and several large areas in the east. The scour depressions tend to have coarser grained sediment than intervening erosional outliers. The coarseness likely creates turbulence in the water over these areas, which prevents fine-grained sediment deposition. Several small areas of megaripples are visible in the bathymetry data in the west. Other sandy areas are typically rippled, with burrows, worm tubes, and starfish present.

  15. Evolution and functional diversity of jellyfish opsins.

    PubMed

    Suga, Hiroshi; Schmid, Volker; Gehring, Walter J

    2008-01-01

    Cnidaria are the most basal animal phylum possessing complex eyes [1]. Their eyes predominantly use ciliary photoreceptor cells (c-PRCs) like vertebrates, whereas insect eyes use rhabdomeric photoreceptor cells (r-PRCs) [1-4]. These two cell types show not only different cytoarchitectures but distinct phototransduction cascades, which are triggered by the respective types of opsins (e.g., [5]), ciliary opsins (c-opsins) and rhabdomeric opsins (r-opsins) [6]. Recent reports suggested that the c- and r-PRCs and their respective opsins diverged at least before the deuterostome-protostome split [7-9]. To study the earlier evolution of animal PRCs and opsins, we investigated two hydrozoan jellyfishes. We report here the first-characterized cnidarian opsins. Molecular phylogeny revealed that the cloned 20 jellyfish opsins, together with all the opsins from a hydra and some from a sea anemone, are more closely related to the c-opsins than to any other major opsin subfamily, indicating that the divergence of c- and r-opsins antedates the Cnidaria-Bilateria split. Possible scenarios of animal PRC evolution are discussed. Furthermore, Cladonema opsins show several distinct tissue- and stage-specific expression patterns. The expression of specific opsins in the eyes suggests a role in vision, whereas that in the gonads suggests a role in light-controlled release of gametes. PMID:18160295

  16. Adhesion networks of cnidarians: a postgenomic view.

    PubMed

    Tucker, Richard P; Adams, Josephine C

    2014-01-01

    Cell-extracellular matrix (ECM) and cell-cell adhesion systems are fundamental to the multicellularity of metazoans. Members of phylum Cnidaria were classified historically by their radial symmetry as an outgroup to bilaterian animals. Experimental study of Hydra and jellyfish has fascinated zoologists for many years. Laboratory studies, based on dissection, biochemical isolations, or perturbations of the living organism, have identified the ECM layer of cnidarians (mesoglea) and its components as important determinants of stem cell properties, cell migration and differentiation, tissue morphogenesis, repair, and regeneration. Studies of the ultrastructure and functions of intercellular gap and septate junctions identified parallel roles for these structures in intercellular communication and morphogenesis. More recently, the sequenced genomes of sea anemone Nematostella vectensis, Hydra magnipapillata, and coral Acropora digitifera have opened up a new frame of reference for analyzing the cell-ECM and cell-cell adhesion molecules of cnidarians and examining their conservation with bilaterians. This chapter integrates a review of literature on the structure and functions of cell-ECM and cell-cell adhesion systems in cnidarians with current analyses of genome-encoded repertoires of adhesion molecules. The postgenomic perspective provides a fresh view on fundamental similarities between cnidarian and bilaterian animals and is impelling wider adoption of species from phylum Cnidaria as model organisms. PMID:24411175

  17. Characterisation of Nitric Oxide Synthase in Three Cnidarian-Dinoflagellate Symbioses

    PubMed Central

    Safavi-Hemami, Helena; Young, Neil D.; Doyle, Jason; Llewellyn, Lyndon; Klueter, Anke

    2010-01-01

    Background Nitric oxide synthase (NOS) is an enzyme catalysing the conversion of L-arginine to L-citrulline and nitric oxide (NO), the latter being an essential messenger molecule for a range of biological processes. Whilst its role in higher vertebrates is well understood little is known about the role of this enzyme in early metazoan groups. For instance, NOS-mediated signalling has been associated with Cnidaria-algal symbioses, however controversy remains about the contribution of enzyme activities by the individual partners of these mutualistic relationships. Methodology/Principal Findings Using a modified citrulline assay we successfully measured NOS activity in three cnidarian-algal symbioses: the sea anemone Aiptasia pallida, the hard coral Acropora millepora, and the soft coral Lobophytum pauciflorum, so demonstrating a wide distribution of this enzyme in the phylum Cnidaria. Further biochemical (citrulline assay) and histochemical (NADPH-diaphorase) investigations of NOS in the host tissue of L. pauciflorum revealed the cytosolic and calcium dependent nature of this enzyme and its in situ localisation within the coral's gastrodermal tissue, the innermost layer of the body wall bearing the symbiotic algae. Interestingly, enzyme activity could not be detected in symbionts freshly isolated from the cnidarians, or in cultured algal symbionts. Conclusions/Significance These results suggest that NOS-mediated NO release may be host-derived, a finding that has the potential to further refine our understanding of signalling events in cnidarian-algal symbioses. PMID:20442851

  18. Dust Storm, Aral Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Aral Sea has shrunk to less than half its size since 1985. The Aral Sea receives little water (sometimes no water) from the two major rivers that empty into it-the Syr Darya and Amu Darya. Instead, the river water is diverted to support irrigation for the region's extensive cotton fields. Recently, water scarcity has increased due to a prolonged drought in Central Asia. As the Aral Sea recedes, its former sea bed is exposed. The Aral's sea bed is composed of fine sediments-including fertilizers and other agricultural chemicals-that are easily picked up by the region's strong winds, creating thick dust storms. The International Space Station crew observed and recorded a large dust storm blowing eastward from the Aral Sea in late June 2001. This image illustrates the strong coupling between human activities (water diversions and irrigation), and rapidly changing land, sea and atmospheric processes-the winds blow across the

  19. First Evidence of Inbreeding, Relatedness and Chaotic Genetic Patchiness in the Holoplanktonic Jellyfish Pelagia noctiluca (Scyphozoa, Cnidaria)

    PubMed Central

    Aglieri, Giorgio; Papetti, Chiara; Zane, Lorenzo; Milisenda, Giacomo; Boero, Ferdinando; Piraino, Stefano

    2014-01-01

    Genetic drift and non-random mating seldom influence species with large breeding populations and high dispersal potential, characterized by unstructured gene pool and panmixia at a scale lower than the minimum dispersal range of individuals. In the present study, a set of nine microsatellite markers was developed and used to investigate the spatio-temporal genetic patterns of the holoplanktonic jellyfish Pelagia noctiluca (Scyphozoa) in the Southern Tyrrhenian Sea. Homozygote excess was detected at eight loci, and individuals exhibited intra-population relatedness higher than expected by chance in at least three samples. This result was supported by the presence of siblings in at least 5 out 8 samples, 4 of which contained full-sib in addition to half-sib dyads. Having tested and ruled out alternative explanations as null alleles, our results suggest the influence of reproductive and behavioural features in shaping the genetic structure of P. noctiluca, as outcomes of population genetics analyses pointed out. Indeed, the genetic differentiation among populations was globally small but highlighted: a) a spatial genetic patchiness uncorrelated with distance between sampling locations, and b) a significant genetic heterogeneity between samples collected in the same locations in different years. Therefore, despite its extreme dispersal potential, P. noctiluca does not maintain a single homogenous population, but rather these jellyfish appear to have intra-bloom localized recruitment and/or individual cohesiveness, whereby siblings more likely swarm together as a single group and remain close after spawning events. These findings provide the first evidence of family structures and consequent genetic patchiness in a species with highly dispersive potential throughout its whole life cycle, contributing to understanding the patterns of dispersal and connectivity in marine environments. PMID:24977703

  20. Evolution of the tetraploid Anemone multifida (2n = 32) and hexaploid A. baldensis (2n = 48) (Ranunculaceae) was accompanied by rDNA loci loss and intergenomic translocation: evidence for their common genome origin

    PubMed Central

    Mlinarec, J.; Šatovi?, Z.; Malenica, N.; Ivan?i?-Ba?e, I.; Besendorfer, V.

    2012-01-01

    Background and Aims In the genus Anemone two small groups of taxa occur with the highest ploidy levels 2n = 6x = 48, belonging to the closely related clades: the montane/alpine Baldensis clade and the more temperate Multifida clade. To understand the formation of polyploids within these groups, the evolution of allohexaploid A. baldensis (AABBDD, 2n = 6x = 48) from Europe and allotetraploid Anemone multifida (BBDD, 2n = 4x = 32) from America was analysed. Methods Internal transcribed spacer and non-transcribed spacer sequences were used as molecular markers for phylogenetic analyses. Cytogenetic studies, including genomic in situ hybridization with genomic DNA of potential parental species as probe, fluorescence in situ hybridization with 5S and 18S rDNA as probes and 18S rDNA restriction analyses, were used to identify the parental origin of chromosomes and to study genomic changes following polyploidization. Key Results This study shows that A. multifida (BBDD, 2n= 4x = 32) and A. baldensis (AABBDD, 2n = 6x = 48) are allopolyploids originating from the crosses of diploid members of the Multifida (donor of the A and B subgenomes) and Baldensis groups (donor of the D subgenome). The A and B subgenomes are closely related to the genomes of A. sylvestris, A. virginiana and A. cylindrica, indicating that these species or their progeny might be the ancestral donors of the B subgenome of A. multifida and A and B subgenomes of A. baldensis. Both polyploids have undergone genomic changes such as interchromosomal translocation affecting B and D subgenomes and changes at rDNA sites. Anemone multifida has lost the 35S rDNA loci characteristic of the maternal donor (B subgenome) and maintained only the rDNA loci of the paternal donor (D subgenome). Conclusions It is proposed that A. multifida and A. baldensis probably had a common ancestor and their evolution was facilitated by vegetation changes during the Quaternary, resulting in their present disjunctive distribution. PMID:22711694

  1. The organizer in evolution-gastrulation and organizer gene expression highlight the importance of Brachyury during development of the coral, Acropora millepora.

    PubMed

    Hayward, David C; Grasso, Lauretta C; Saint, Robert; Miller, David J; Ball, Eldon E

    2015-03-15

    Organizer activity, once thought to be restricted to vertebrates, has ancient origins. However, among non-bilaterians, it has only been subjected to detailed investigation during embryonic development of the sea anemone, Nematostella vectensis. As a step toward establishing the extent to which findings in Nematostella can be generalized across the large and diverse phylum Cnidaria, we examined the expression of some key organizer and gastrulation genes during the embryonic development of the coral Acropora millepora. Although anemones and corals both belong to the cnidarian class Anthozoa, the two lineages diverged during the Cambrian and the morphological development of Acropora differs in several important respects from that of Nematostella. While the expression patterns of the key genes brachyury, bmp2/4, chordin, goosecoid and forkhead are broadly similar, developmental differences between the two species enable novel observations, and new interpretations of their significance. Specifically, brachyury expression during the flattened prawnchip stage before gastrulation, a developmental peculiarity of Acropora, leads us to suggest that it is the key gene demarcating ectoderm from endoderm in Acropora, and by implication in other cnidarians, whereas previous studies in Nematostella proposed that forkhead plays this role. Other novel observations include the transient expression of Acropora forkhead in scattered ectodermal cells shortly after gastrulation, and in the developing mesenterial filaments, with no corresponding expression reported in Nematostella. In addition, the expression patterns of goosecoid and bmp2/4 confirm the fundamental bilaterality of the Anthozoa. PMID:25601451

  2. Sea level extremes in the Caribbean Sea

    NASA Astrophysics Data System (ADS)

    Torres, R. Ricardo; Tsimplis, Michael N.

    2014-08-01

    Sea level extremes in the Caribbean Sea are analyzed on the basis of hourly records from 13 tide gauges. The largest sea level extreme observed is 83 cm at Port Spain. The largest nontidal residual in the records is 76 cm, forced by a category 5 hurricane. Storm surges in the Caribbean are primarily caused by tropical storms and stationary cold fronts intruding the basin. However, the seasonal signal and mesoscale eddies also contribute to the creation of extremes. The five stations that have more than 20 years of data show significant trends in the extremes suggesting that flooding events are expected to become more frequent in the future. The observed trends in extremes are caused by mean sea level rise. There is no evidence of secular changes in the storm activity. Sea level return periods have also been estimated. In the south Colombian Basin, where large hurricane-induced surges are rare, stable estimates can be obtained with 30 years of data or more. For the north of the basin, where large hurricane-induced surges are more frequent, at least 40 years of data are required. This suggests that the present data set is not sufficiently long for robust estimates of return periods. ENSO variability correlates with the nontidal extremes, indicating a reduction of the storm activity during positive ENSO events. The period with the highest extremes is around October, when the various sea level contributors' maxima coincide.

  3. THE SEALS, SEA-LIONS, AND SEA OTTER OF

    E-print Network

    THE SEALS, SEA-LIONS, AND SEA OTTER OF THE PACIFIC COAST Marine Biological Laboratory OODS HOLE, SEA-LIONS, AND SEA OTTER OF THE PACIFIC COAST Descriptions, Life History Notes, Photographs, and sea otter of the Pacific from Mexico to Point Barrow and the Hawaiian Islands. For each of twelve

  4. Sea Ice Variability in the Bering Sea

    NASA Astrophysics Data System (ADS)

    Li, L.; Miller, A. J.; McClean, J.; Eisenman, I.; Hendershott, M.

    2013-12-01

    The Bering Sea consists of a shallow continental shelf in the northeast and a deep basin in the southwest. Sea ice in the Bering Sea concentrating in the shelf region exhibits large seasonal and interannual variations, which significantly impact the local marine ecosystem. Understanding of the physical mechanisms governing this sea-ice variability, however, remains incomplete. To better understand regional sea-ice variability we use a fine resolution (1/10-degree) global ocean and sea-ice model and available observations. The simulation consists of the Los Alamos National Laboratory Parallel Ocean Program (POP) and CICE models, and was run with Coordinated Ocean-ice Reference Experiment (CORE2) interannually varying atmospheric forcing for 1970-1989. Here we analyze 1980-1989; the first 10 years are treated as the spin-up period. We examine the partitioning of the ice volume tendencies into thermodynamic and dynamic components, as well as corresponding surface atmospheric and oceanic variables, in order to understand the relationship between sea ice variability and varying atmospheric and oceanic conditions. Focusing on the seasonal cycle first, we find that sea ice is mainly formed in the northern Bering Sea with the maximum ice growth rate occurring along the coast. Winds cause sea ice to drift southwestward from the north to the western ice edge. Along the ice edge, ice is melted by warm waters carried by the Bering Slope Current, especially in the west in winter; while in fall and spring, basal melting of sea ice spreads into the interior of ice pack. The ice growth rate is larger in winter than in fall and spring. Ice transport from the north to the southwest becomes weaker in fall and spring than in winter. The Bering Sea is ice free in summer. Surface melting is insignificant in all seasons. The interannual variability of sea ice in the Bering Sea can be largely explained by thermodynamics on the large scale. The dynamic ice transport, however, is often important locally, especially around the ice margins with ocean and land. Local dynamic and thermodynamic ice volume changes usually have opposite signs with similar magnitudes, implying a negative feedback between them. Through the surface heat flux budget, we find that sensible heat flux dominates the surface heat exchange with the atmosphere, which controls the ice growth in the north. Ocean-ice heat flux largely determines the basal melting along the ice edge in the south. Through the force balance analysis, we find that the ice motion is in steady state on the monthly timescale. Ice velocity correlates well with the wind stress, which is nearly balanced by the opposite ocean stress. Internal ice stress is not substantial except near the land boundaries in the north.

  5. East Siberian Sea, Russia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The winter sea ice in the east Siberian Sea is looking a bit like a cracked windshield in these true-color Moderate Resolution Imaging Spectroradiometer (MODIS) images from June 16 and 23, 2002. North of the thawing tundra, the sea ice takes on its cracked, bright blue appearance as it thins, which allows the reflection of the water to show through. Numerous still-frozen lakes dot the tundra. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  6. Focus on Sea Otters

    NSDL National Science Digital Library

    A Monterey Bay Aquarium website where you can learn about the biology and population recovery of sea otters. Features include the opportunity to "meet" the otters on exhibit at the aquarium and viewing them through the live otter cam. Many sea otter-related games, activities, and resources. Links to other fascinating exhibits at the Aquarium. Several downloadable videos available, each with their own enjoyable sea otter antics.

  7. SeaWIFS Project

    NSDL National Science Digital Library

    SeaWIFS (Sea-viewing Wide Field-of-view Sensor), a NASA project using satellites to collect ocean color data to quantify phytoplankton abundance. Provides background information on SeaWIFS project, technology and data. Teacher Resource section has: online presentation on how and why scientists study ocean color; Living Ocean Teacher's Guide with brief information on ocean color, carbon cycle and greenhouse gas effect; and, links to other websites with ocean color activities.

  8. Sea Turtle Science

    NSDL National Science Digital Library

    This packet includes background information, quick facts, links to additional sea turtle resources, and a classroom modeling activity that demonstrates population estimation, life history, and hatching success rates.

  9. Pelagic sea snakes dehydrate at sea.

    PubMed

    Lillywhite, Harvey B; Sheehy, Coleman M; Brischoux, François; Grech, Alana

    2014-05-01

    Secondarily marine vertebrates are thought to live independently of fresh water. Here, we demonstrate a paradigm shift for the widely distributed pelagic sea snake, Hydrophis (Pelamis) platurus, which dehydrates at sea and spends a significant part of its life in a dehydrated state corresponding to seasonal drought. Snakes that are captured following prolonged periods without rainfall have lower body water content, lower body condition and increased tendencies to drink fresh water than do snakes that are captured following seasonal periods of high rainfall. These animals do not drink seawater and must rehydrate by drinking from a freshwater lens that forms on the ocean surface during heavy precipitation. The new data based on field studies indicate unequivocally that this marine vertebrate dehydrates at sea where individuals may live in a dehydrated state for possibly six to seven months at a time. This information provides new insights for understanding water requirements of sea snakes, reasons for recent declines and extinctions of sea snakes and more accurate prediction for how changing patterns of precipitation might affect these and other secondarily marine vertebrates living in tropical oceans. PMID:24648228

  10. Hawksbill Sea Turtle (Eretmochelys imbricata)

    USGS Multimedia Gallery

    Hawksbill Sea Turtles (Eretmochelys imbricata), such as the one hiding here under a boulder, and Green Sea Turtles (Chelonia mydas) are occasionally seen in Hurricane Hole. Hawksbills feed mostly on sponges while Greens eat mostly sea grasses....

  11. Kara Sea radioactivity assessment

    Microsoft Academic Search

    Iolanda Osvath; Pavel P Povinec; Murdoch S Baxter

    1999-01-01

    Investigations following five international expeditions to the Kara Sea have shown that no radiologically significant contamination has occurred outside of the dumping sites in Novaya Zemlya bays. Increased levels of radionuclides in sediment have only been observed in Abrosimov and Stepovoy Bays very close to dumped containers. Evaluations of radionuclide inventories in water and sediment of the open Kara Sea

  12. Bering Sea Expedition

    NSDL National Science Digital Library

    Alaska Seas and Rivers Curriculum

    In this investigation learners research the effects of melting sea ice in the Bering Sea Ecosystem. They create research proposals to earn a place on the scientific research vessel Healy and present their findings and proposals to a Research Board committee.

  13. Tracking Sea Otters

    USGS Multimedia Gallery

    USGS wildlife biologist Alisha Kage holds out a VHF receiver, hoping to hear the tell-tale beep that helps her locate sea otters that are part of study to monitor and learn more about the species. USGS scientists study sea otters in efforts to help the threatened species continue to recover from nea...

  14. Spotting Sea Otters

    USGS Multimedia Gallery

    USGS wildlife biologist Alisha Kage looks through a telescope to help her locate and identify tagged sea otters, then records the otter's location for a study aimed at learning more about the species. USGS scientists study sea otters in efforts to help the threatened species continue to recover from...

  15. Sea wave energy conversion

    Microsoft Academic Search

    Perkins; C. A. Jr

    1978-01-01

    A fixed structure encloses a vertically spaced plurality of superimposed channels that are open at one end of the sea to receive deep sea waves approaching a shoreline. Each of the channels has an entrance ramp that slopes upwardly shorewardly to induce breaking of a wave at and over an apex of the ramp that merges into a shorewardly downwardly

  16. Getting Your Sea Legs

    PubMed Central

    Stoffregen, Thomas A.; Chen, Fu-Chen; Varlet, Manuel; Alcantara, Cristina; Bardy, Benoît G.

    2013-01-01

    Sea travel mandates changes in the control of the body. The process by which we adapt bodily control to life at sea is known as getting one's sea legs. We conducted the first experimental study of bodily control as maritime novices adapted to motion of a ship at sea. We evaluated postural activity (stance width, stance angle, and the kinematics of body sway) before and during a sea voyage. In addition, we evaluated the role of the visible horizon in the control of body sway. Finally, we related data on postural activity to two subjective experiences that are associated with sea travel; seasickness, and mal de debarquement. Our results revealed rapid changes in postural activity among novices at sea. Before the beginning of the voyage, the temporal dynamics of body sway differed among participants as a function of their (subsequent) severity of seasickness. Body sway measured at sea differed among participants as a function of their (subsequent) experience of mal de debarquement. We discuss implications of these results for general theories of the perception and control of bodily orientation, for the etiology of motion sickness, and for general phenomena of perceptual-motor adaptation and learning. PMID:23840560

  17. Red sea drillings

    USGS Publications Warehouse

    Ross, D.A.; Whitmarsh, R.B.; Ali, S.A.; Boudreaux, J.E.; Coleman, R.; Fleisher, R.L.; Girdler, R.; Manheim, F.; Matter, A.; Nigrini, C.; Stoffers, P.; Supko, P.R.

    1973-01-01

    Recent drilling in the Red Sea has shown that much of the basin is underlain by evaporites of a similar age to that of evaporites found in the Mediterranean Sea. These evaporites and their structural positions indicate that other brine areas are present - and, indeed, several others have been discovered.

  18. Sea Level Viewer

    NSDL National Science Digital Library

    Randall Jackson

    Video and animations of sea level from NASA's Climate website. Since 1992, NASA and CNES have studied sea surface topography as a proxy for ocean temperatures. NASA Missions TOPEX/Poseidon, Jason 1 and Jason 2 have been useful in predicting major climate, weather, and geologic events including El Nino, La Nina, Hurricane Katrina, and the Indian Ocean Tsunami.

  19. White Sea - Russia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    At bottom center of this true-color Moderate Resolution Imaging Spectroradiometer (MODIS) image from April 13, 2001, the White Sea in western Russia is becoming free of ice in its southern extent. Meanwhile, the blue-green waters along the coast of the peninsula jutting out into the Barents Sea to the northeast could be due to a phytoplankton bloom.

  20. Antarctica: Sea Ice

    NSDL National Science Digital Library

    This video segment, adapted from a NOVA broadcast, shows how sea ice forms in the Southern Ocean around Antarctica and how its seasonal fluctuation dramatically changes the continent. The segment, two minutes thirty-five seconds in length, includes rare footage of the destruction of the British ship 'Endurance', trapped and crushed by sea ice in 1914.

  1. Tracking Sea Turtles

    NSDL National Science Digital Library

    Classroom activity introduces the biology of sea turtles, population status, human impacts. Focuses on Kemp's ridley (Lepidochelys kempii), smallest and more endangered of sea turtle species. This teacher's guide provides NOAA tracking data and instructions for students to follow the migration routes of six turtles in the Gulf of Mexico. Links to related activities using satellite data.

  2. Sea Lion Skeleton - Skull

    NSDL National Science Digital Library

    Ketan Patel (California State University, Fullerton; Student, Biological Sciences)

    2007-07-26

    The carnivorous sea lion uses its sharp pointed teeth and large mouth to shred and tear its prey. The large nose and large eyes on either side of the skull help the sea lion to detect prey. The skull protects the brain from damage and injury.

  3. Sea Lion Skeleton - Nostrils

    NSDL National Science Digital Library

    Ketan Patel (California State University, Fullerton; Student, Biological Sciences)

    2007-07-26

    The carnivorous sea lion uses its sharp pointed teeth and large mouth to shred and tear its prey. The large nose and large eyes on either side of the skull help the sea lion to detect prey. The skull protects the brain from damage and injury.

  4. Black Sea in Bloom

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This true-color image shows bright, turquoise-colored swirls across the surface of the Black Sea, signifying the presence of a large phytoplankton bloom. Scientists have observed similar blooms recurring annually, roughly this same time of year. The Sea of Azov, which is the smaller body of water located just north of the Black Sea in this image, also shows a high level of biological activity currently ongoing. The brownish pixels in the Azov are probably sediments carried in from high waters upstream. This scene was acquired by the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), flying aboard the OrbView-2 satellite, on May 4, 2002. According to the Black Sea Environment Programme's Marine Hydrophysical Institute, the Black Sea is 'one of the marine areas of the world most damaged by human activities.' The coastal zone around these Eastern European inland water bodies is densely populated-supporting a permanent population of roughly 16 million people and another 4 million tourists each year. Six countries border with the Black Sea, including Ukraine to the north, Russia and Georgia to the east, Turkey to the south, and Bulgaria and Romania to the west. Because it is isolated from the world's oceans, and because there is an extensive drainage network of rivers that empty into it, the Black Sea has a unique and delicate water balance which is very important for supporting its marine ecosystem. Of particular concern to scientists is the salinity, water level, and nutrient levels of the Black Sea's waters, all of which are, unfortunately, being impacted by human activities. Within the last three decades the combination of increased nutrient loads from human sources together with pollution and over-harvesting of fisheries has resulted in a sharp decline in water quality. Scientists from each of the Black Sea's bordering nations are currently working together to study the issues and formulate a joint, international strategy for saving this unique marine ecosystem. Working with a spirit of placing more emphasis on joint ownership of the Black Sea's resources, and less emphasis on blame, it is hoped that the cooperating countries can strike an effective balance between both enjoying and preserving the Black Sea. Image courtesy the SeaWiFS Project, NASA GSFC, and ORBIMAGE

  5. Semi-Automated Image Analysis for the Assessment of Megafaunal Densities at the Arctic Deep-Sea Observatory HAUSGARTEN

    PubMed Central

    Schoening, Timm; Bergmann, Melanie; Ontrup, Jörg; Taylor, James; Dannheim, Jennifer; Gutt, Julian; Purser, Autun; Nattkemper, Tim W.

    2012-01-01

    Megafauna play an important role in benthic ecosystem function and are sensitive indicators of environmental change. Non-invasive monitoring of benthic communities can be accomplished by seafloor imaging. However, manual quantification of megafauna in images is labor-intensive and therefore, this organism size class is often neglected in ecosystem studies. Automated image analysis has been proposed as a possible approach to such analysis, but the heterogeneity of megafaunal communities poses a non-trivial challenge for such automated techniques. Here, the potential of a generalized object detection architecture, referred to as iSIS (intelligent Screening of underwater Image Sequences), for the quantification of a heterogenous group of megafauna taxa is investigated. The iSIS system is tuned for a particular image sequence (i.e. a transect) using a small subset of the images, in which megafauna taxa positions were previously marked by an expert. To investigate the potential of iSIS and compare its results with those obtained from human experts, a group of eight different taxa from one camera transect of seafloor images taken at the Arctic deep-sea observatory HAUSGARTEN is used. The results show that inter- and intra-observer agreements of human experts exhibit considerable variation between the species, with a similar degree of variation apparent in the automatically derived results obtained by iSIS. Whilst some taxa (e. g. Bathycrinus stalks, Kolga hyalina, small white sea anemone) were well detected by iSIS (i. e. overall Sensitivity: 87%, overall Positive Predictive Value: 67%), some taxa such as the small sea cucumber Elpidia heckeri remain challenging, for both human observers and iSIS. PMID:22719868

  6. Sea Cucumbers (Holothuroidea)

    NSDL National Science Digital Library

    This Report's Topic in Depth explores the world of sea cucumbers, or Holothuroidea, a diverse group of intriguing marine animals. The first site (1), from the Tree of Life Web Project, provides nice clear images of sea cucumbers and brief concise sections on Characteristics, The Orders of Holothuroidea, Fossil History, and Discussion of Phylogenetic Relationships. The second site (2), from the Charles Darwin Research Station, displays short answers to commonly asked questions about sea cucumbers like: What is their importance within the marine communities?; How do sea cucumbers reproduce?; and What is the potential environment impact of overexploiting sea cucumber populations? From Enchanted Learning, the third site (3) features a diagrammed print-out of a s ea cucumber along with short descriptions of Holothuroidea anatomy, diet, classification, and predators. Hosted by the Royal BC Museum, the fourth site (4) contains a brief research paper by curator Philip Lambert on taxonomy issues concerning sea cucumbers. The fifth site (5), developed by Richard Fox of Lander University, contains detailed instructions for a laboratory exercise with Sclerodactyla briareus, a species of sea cucumber. From MoonDragon's Health & Wellness website, the sixth site (6) contains a sea cucumber recipe and briefly discusses sea cucumber cuisine and health benefits. Hosted by the Secretariat of the Pacific Community, the seventh site (7) provides information about an international conference titled: Conservation of s ea cucumbers in Malaysia, their Taxonomy, Ecology and Trade. The site contains concluding remarks, abstracts from papers presented at the conference, and a list of email contacts for conference participants. The final (8) site from the Environmental News Network'features a short article about an Ecuadorian court upholding sea cucumber fishing limits in the Galapagos islands.

  7. KILLER WHALES PURSUE SEA LIONS IN BERING SEA DRAMA

    E-print Network

    KILLER WHALES PURSUE SEA LIONS IN BERING SEA DRAMA Jim Branson NMFS Fisheries Management Agent a pod of 7 killer whales ( rampus vectipinna) pursue a band of 20 to ~' 5 Steller sea lions (Eumetopias E of N from Bogoslof Island, a very large sea lion rookery. At the time, there were 9 SRTMs

  8. SEAS Safety Program SEAS SAFETY PROGRAM 2012-2103

    E-print Network

    Streeto · Biosafety Manager: Sid Paula · Laser Safety Officer: Xiaowei Yan · Radiation Safety: StephenSEAS Safety Program SEAS SAFETY PROGRAM 2012-2103 Program Structure and Responsibilities Dr. Anas Chalah #12;SEAS Safety Program SEAS Safety Program Structure We have developed a great model

  9. Global sea level rise

    SciTech Connect

    Douglas, B.C. (NOAA, Rockville, MD (USA))

    1991-04-15

    Published values for the long-term, global mean sea level rise determined from tide gauge records exhibit considerable scatter, from about 1 mm to 3 mm/yr. This disparity is not attributable to instrument error; long-term trends computed at adjacent sites often agree to within a few tenths of a millimeter per year. Instead, the differing estimates of global sea level rise appear to be in large part due to authors' using data from gauges located at convergent tectonic plate boundaries, where changes of land elevation give fictitious sea level trends. In addition, virtually all gauges undergo subsidence or uplift due to postglacial rebound (PGR) from the last deglaciation at a rate comparable to or greater than the secular rise of sea level. Modeling PGR by the ICE-3G model of Tushingham and Peltier (1991) and avoiding tide gauge records in areas of converging tectonic plates produces a highly consistent set of long sea level records. The value for mean sea level rise obtained from a global set of 21 such stations in nine oceanic regions with an average record length of 76 years during the period 1880-1980 is 1.8 mm/yr {plus minus} 0.1. This result provides confidence that carefully selected long tide gauge records measure the same underlying trend of sea level and that many old tide gauge records are of very high quality.

  10. Arctic Sea Ice

    NSDL National Science Digital Library

    Beverly L. Meier

    2012-06-26

    In this activity, learners explore how the area of Arctic sea ice has changed over recent years. First, learners graph the area of Arctic sea ice over time from 1979 to 2007. Then, learners use this information to extrapolate what the area will be in 2018 and graph their predictions. In part two of the activity, learners make a flip book to simulate the sea changes they just graphed. This resource includes background information related to the Northwest Passage and questions for learners to answer after completing this activity.

  11. Is The Sea Level?

    NSDL National Science Digital Library

    2007-12-12

    In this activity students will observe that the sea level changes and will hypothesize what causes this change. They will then check their hypothesis with a data set. Many students are surprised to learn that sea level is not the same everywhere on earth and that it changes with the seasons. The main cause of this change is the temperature change in the ocean - warmer waters are higher than colder waters. Students will discover this information as they complete the activity and then see if the temperature effect holds true on another data set showing temperature and sea height changes caused by the El Nino/Southern Oscillation (ENSO).

  12. Sea level variation

    NASA Technical Reports Server (NTRS)

    Douglas, Bruce C.

    1992-01-01

    Published values for the long-term, global mean sea level rise determined from tide gauge records range from about one to three mm per year. The scatter of the estimates appears to arise largely from the use of data from gauges located at convergent tectonic plate boundaries where changes of land elevation give fictitious sea level trends, and the effects of large interdecadal and longer sea level variations on short (less than 50+ years) or sappy records. In addition, virtually all gauges undergo subsidence or uplift due to isostatic rebound from the last deglaciation at a rate comparable to or greater than the secular rise of sea level. Modeling rebound by the ICE-3G model of Tushingham and Peltier (1990) and avoiding tide gauge records in areas of converging tectonic plates produces a highly consistent set of long sea level records. A global set of 21 such stations in nine oceanic regions with an average record length of 76 years during the period 1880-1980 yields the global sea level rise value 1.8 mm/year +/- 0.1. Greenhouse warming scenarios commonly forecast an additional acceleration of global sea level in the next 5 or 6+ decades in the range 0.1-0.2 mm/yr2. Because of the large power at low frequencies in the sea level spectrum, very long tide gauge records (75 years minimum) have been examined for past apparent sea level acceleration. For the 80-year period 1905-1985, 23 essentially complete tide gauge records in 10 geographic groups are available for analysis. These yielded the apparent global acceleration -0.011 (+/- 0.012) mm/yr2. A larger, less uniform set of 37 records in the same 10 groups with 92 years average length covering the 141 years from 1850-1991 gave 0.001 (+/- 0.008) mm/yr2. Thus there is no evidence for an apparent acceleration in the past 100+ years that is significant either statistically, or in comparison to values associated with global warming. Unfortunately, the large interdecadal fluctuations of sea level severely affect estimates of global sea level acceleration for time spans of less than about 50 years. This means that tide gauges alone cannot serve as a reliable leading indicator of climate change in less than many decades. This time required can be significantly reduced if the interdecadal fluctuations of sea level can be understood in terms of their forcing mechanisms, and then removed from the tide gauge records.

  13. Epibenthic assemblages in the Celtic Sea and associated with the Jones Bank

    NASA Astrophysics Data System (ADS)

    Ellis, J. R.; Martinez, I.; Burt, G. J.; Scott, B. E.

    2013-10-01

    The epibenthic assemblages in the Celtic Sea are described from the catches from 2 m beam trawl surveys undertaken from 2000 to 2009. During this period 154 samples were collected. The most ubiquitous species in the study area were the natantid shrimps Processa spp. and Crangon allmanni, the hermit crabs Pagurus prideaux and Anapagurus laevis, sand star Astropecten irregularis and spotted dragonet Callionymus maculatus. Multivariate community analyses indicated that catches (numbers per tow) were distributed across six assemblages, two of which were predominant in the study area. Most catches were attributed to either a 'shelf edge assemblage', which was widespread in deeper waters (114-423 m water depth) or an 'outer shelf assemblage' that occurred across much of the Celtic Sea north of 49°N in waters 49-175 m deep. The dominant species along the edge of the continental shelf were the hormathid anemome Actinauge richardi, sea spider Pycnogonum littorale (which associated with A. richardi), Devonshire cup coral Caryophyllia smithii and the swimming crab Macropipus tuberculatus. The dominant species in the outer shelf assemblage included P. prideaux, C. allmanni, A. laevis and common starfish Asterias rubens. Stations closer to shore were relatively distinct and catches in this 'inner shelf assemblage' were composed primarily of an inshore fauna (e.g. Ophiura ophiura, C. allmanni and Liocarcinus holsatus). Stations in the southern part of the survey grid were also relatively distinct ('southern Celtic Sea assemblage'), and several large echinoderms (Porania pulvillus, Stichastrella rosea and Anseropoda placenta) dominated at these sites. Three of the deepest stations were also relatively distinct, as were a group of stations in the muddy habitat of the Celtic Deep and comparable grounds elsewhere in the region, where Nucula sulcata and Alpheus glaber were characteristic. Catches on the shallower parts of the Jones Bank (and on another bank in the region) were dominated by the anemone Paraphellia expansa, with off-bank sites comprising a greater number of species. In contrast to beam trawl sampling, baited camera observations on the Jones Bank showed a greater richness of species on the shallower part of the bank, and provided information on the nocturnal feeding behaviour of scavenging isopods.

  14. Sea Level: On The Rise

    NSDL National Science Digital Library

    2013-11-26

    Learners will understand the relationship between climate change and sea-level rise. In the first activity, they will learn that heated water causes sea level to rise through a process called thermal expansion. They will also perform an experiment to learn that melting land-based ice contributes to greater sea-level rise than melting sea ice.

  15. A Sea Experience.

    ERIC Educational Resources Information Center

    Glickstein, Neil

    1989-01-01

    Described is a teacher education program organized by the Sea Education Association in Woods Hole (Massachusetts). The experience, including activities and examples of studies conducted, is discussed. Contact information for future cruises is included. (CW)

  16. Dead Sea Scrolls

    NASA Technical Reports Server (NTRS)

    1994-01-01

    A consortium of researchers from Jet Propulsion Laboratory and three other organizations used charged coupled devices (CCDs) and other imaging enhancement technology to decipher previously unreadable portions of the Dead Sea Scrolls. The technique has potentially important implications for archeology.

  17. Sea level change

    SciTech Connect

    Meier, M.F. [Univ. of Colorado, Boulder, CO (United States)

    1996-12-31

    The IPCC (Intergovernmental Panel on Climate Change) 1995 Scientific Assessment, Chapter 7. Sea Level Change, presents a modest revision of the similar chapter in the 1990 Assessment. Principal conclusions on observed sea-level change and the principal terms in the sea-level equation (ocean thermal expansion, glaciers, ice sheets, and land hydrology), including our knowledge of the present-day (defined as the 20th Century) components of sea-level rise, and projections of these for the future, are presented here. Some of the interesting glaciological problems which are involved in these studies are discussed in more detail. The emphasis here is on trends over decades to a century, not on shorter variations nor on those of the geologic past. Unfortunately, some of the IPCC projections had not been agreed at the time of writing of this paper, and these projections will not be given here. 15 refs., 2 figs.

  18. Purple sea urchin swarm

    NSDL National Science Digital Library

    Katie Hale (California State University, Fullerton; Student, Biological Sciences)

    2007-01-04

    Sea urchins live in low tide regions and eat seaweed. Urchins have no arms but have five rows of tube feet for movement. They are found in holes and use their spines for protection and to burrow into the rocks.

  19. Sea Floor Spreading I

    NSDL National Science Digital Library

    Activity and Starting Point page by R.M. MacKay. Clark College, Physics and Meteorology.

    In this introductory Excel tutorial (Activity I) students use Excel to explore the geodynamics model equation for ocean depth around a sea-floor spreading center. For students with no prior Excel experience.

  20. Record Sea Ice Minimum

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Arctic sea ice reached a record low in September 2007, below the previous record set in 2005 and substantially below the long-term average. This image shows the Arctic as observed by the Advanced Microwave Scanning Radiometer for EOS (AMSR-E) aboard NASA's Aqua satellite on September 16, 2007. In this image, blue indicates open water, white indicates high sea ice concentration, and turquoise indicates loosely packed sea ice. The black circle at the North Pole results from an absence of data as the satellite does not make observations that far north. Three contour lines appear on this image. The red line is the 2007 minimum, as of September 15, about the same time the record low was reached, and it almost exactly fits the sea ice observed by AMSR-E. The green line indicates the 2005 minimum, the previous record low. The yellow line indicates the median minimum from 1979 to 2000.

  1. Sea ice ecosystems.

    PubMed

    Arrigo, Kevin R

    2014-01-01

    Polar sea ice is one of the largest ecosystems on Earth. The liquid brine fraction of the ice matrix is home to a diverse array of organisms, ranging from tiny archaea to larger fish and invertebrates. These organisms can tolerate high brine salinity and low temperature but do best when conditions are milder. Thriving ice algal communities, generally dominated by diatoms, live at the ice/water interface and in recently flooded surface and interior layers, especially during spring, when temperatures begin to rise. Although protists dominate the sea ice biomass, heterotrophic bacteria are also abundant. The sea ice ecosystem provides food for a host of animals, with crustaceans being the most conspicuous. Uneaten organic matter from the ice sinks through the water column and feeds benthic ecosystems. As sea ice extent declines, ice algae likely contribute a shrinking fraction of the total amount of organic matter produced in polar waters. PMID:24015900

  2. Sea Ice Ecosystems

    NASA Astrophysics Data System (ADS)

    Arrigo, Kevin R.

    2014-01-01

    Polar sea ice is one of the largest ecosystems on Earth. The liquid brine fraction of the ice matrix is home to a diverse array of organisms, ranging from tiny archaea to larger fish and invertebrates. These organisms can tolerate high brine salinity and low temperature but do best when conditions are milder. Thriving ice algal communities, generally dominated by diatoms, live at the ice/water interface and in recently flooded surface and interior layers, especially during spring, when temperatures begin to rise. Although protists dominate the sea ice biomass, heterotrophic bacteria are also abundant. The sea ice ecosystem provides food for a host of animals, with crustaceans being the most conspicuous. Uneaten organic matter from the ice sinks through the water column and feeds benthic ecosystems. As sea ice extent declines, ice algae likely contribute a shrinking fraction of the total amount of organic matter produced in polar waters.

  3. Sensing the sea bed

    NASA Astrophysics Data System (ADS)

    2009-07-01

    William Wilcock and a team of scientists and engineers drilled holes in the sea floor, and inadvertently provided a breeding ground for octopuses, in their attempt to understand deep-ocean hydrothermal venting.

  4. Smart Sea Lions

    NSDL National Science Digital Library

    2009-08-27

    This video segment adapted from NOVA scienceNOW explores whether animals and humans are more similar than we think. Meet Rio, a sea lion who demonstrates to researchers reasoning skills once thought limited to humans.

  5. Science at Sea.

    ERIC Educational Resources Information Center

    Phillips, Mary Nied

    2001-01-01

    Describes a three-week inservice teacher education program that involves two sessions of preparatory classes ashore in nautical science and oceanography, and concludes with a nine-day sea voyage. (ASK)

  6. Stellar Sea Lion Research

    NSDL National Science Digital Library

    The phenomenon is the decline in population of western Stellar Sea Lions from 1969 to 1986, shown in a series of three images. The accompanying text describes the possible factors that may be contributing to the change in population.

  7. South China Sea.

    PubMed

    Morton, B; Blackmore, G

    2001-12-01

    The South China Sea is poorly understood in terms of its marine biota, ecology and the human impacts upon it. What is known is most often contained in reports and workshop and conference documents that are not available to the wider scientific community. The South China Sea has an area of some 3.3 million km2 and depths range from the shallowest coastal fringe to 5377 m in the Manila Trench. It is also studded with numerous islets, atolls and reefs many of which are just awash at low tide. It is largely confined within the Tropic of Cancer and, therefore, experiences a monsoonal climate being influenced by the Southwest Monsoon in summer and the Northeast Monsoon in winter. The South China Sea is a marginal sea and, therefore, largely surrounded by land. Countries that have a major influence on and claims to the sea include China, Malaysia, the Philippines and Vietnam, although Thailand, Indonesia and Taiwan have some too. The coastal fringes of the South China Sea are home to about 270 million people that have had some of the fastest developing and most vibrant economies on the globe. Consequently, anthropogenic impacts, such as over-exploitation of resources and pollution, are anticipated to be huge although, in reality, relatively little is known about them. The Indo-West Pacific biogeographic province, at the centre of which the South China Sea lies, is probably the world's most diverse shallow-water marine area. Of three major nearshore habitat types, i.e., coral reefs, mangroves and seagrasses, 45 mangrove species out of a global total of 51, most of the currently recognised 70 coral genera and 20 of 50 known seagrass species have been recorded from the South China Sea. The island groups of the South China Sea are all disputed and sovereignty is claimed over them by a number of countries. Conflicts have in recent decades arisen over them because of perceived national rights. It is perhaps because of this that so little research has been undertaken on the South China Sea. What data are available, however, and if Hong Kong is used, as it is herein, as an indicator of what the perturbations of other regional cities upon the South China Sea are like, then it is impacted grossly and an ecological disaster has probably already, but unknowingly, happened. PMID:11827109

  8. Black Sea Becomes Turquoise

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This true-color image shows bright, turquoise-colored swirls across the surface of the Black Sea, signifying the presence of a large phytoplankton bloom. Scientists have observed similar blooms recurring annually, roughly this same time of year. The Sea of Azov, which is the smaller body of water located just north of the Black Sea in this image, also shows a high level of color variance. The brownish pixels in the Azov are probably due to sediments carried in from high waters and snowmelt from upstream. This scene was acquired by the Moderate Resolution Imaging Spectroradiometer, flying aboard NASA's Terra satellite, on May 14, 2002. According to the Black Sea Environment Programme's Marine Hydrophysical Institute, the Black Sea is ?one of the marine areas of the world most damaged by human activities.? The coastal zone around these Eastern European inland water bodies is densely populated'supporting a permanent population of roughly 16 million people and another 4 million tourists each year. Six countries border with the Black Sea, including Ukraine to the north, Russia and Georgia to the east, Turkey to the south, and Bulgaria and Romania to the west. Because it is isolated from the world's oceans, and because there is an extensive drainage network of rivers that empty into it, the Black Sea has a unique and delicate water balance which is very important for supporting its marine ecosystem. Of particular concern to scientists is the salinity, water level, and nutrient levels of the Black Sea's waters, all of which are, unfortunately, being impacted by human activities. Within the last three decades the combination of increased nutrient loads from human sources together with pollution and over-harvesting of fisheries has resulted in a sharp decline in water quality. Scientists from each of the Black Sea's bordering nations are currently working together to study the issues and formulate a joint, international strategy for saving this unique marine ecosystem. Working with a spirit of placing more emphasis on joint ownership of the Black Sea's resources, and less emphasis on blame, it is hoped that the cooperating countries can strike an effective balance between both enjoying and preserving the Black Sea.

  9. Green Sea Turtles

    NSDL National Science Digital Library

    Detailed information on the biology, natural history, factors influencing the population, and protection measures of green sea turtles (Chelonia mydas). Included are three in-class activities and one field activity all designed to raise awareness of the green sea turtle and what humans are doing to affect the population. The site is geared towards the Hawaiian sub-species, however, most of the facts and activities are applicable elsewhere.

  10. National Sea Grant Library

    NSDL National Science Digital Library

    Only facility housing complete collection of Sea Grant funded work. An archive and lending library for reprints, books, reports, maps, newsletters, handbooks, videos, CD-roms and computer programs regarding: oceanography; marine education; aquaculture; fisheries; limnology; coastal zone management; marine recreation and law. Lends documents worldwide, aiding scientists, teachers, students, fishermen and others in research and study. Bibliographic database is searchable from the website, obtain citations, abstracts and over 20,000 downloadable texts of Sea Grant publications.

  11. Sea Urchin Embryology

    NSDL National Science Digital Library

    Advanced high school level laboratory activities using sea urchins to observe fertilization and early developmental stages. This is a comprehensive site complete with multiple labs, support lessons, background information, animated graphics illustrating lab techniques, printable overheads (also available in Spanish and French), and a glossary of terms. A one-stop site for sea urchin information, experiments, suppliers, and research. Links to additional resources are available.

  12. All About Sea Ice

    NSDL National Science Digital Library

    This comprehensive site is an introduction to sea ice: what it is, how it forms, how it is studied, how it affected historical expedition in the polar regions, and what role it plays in the global climate. The site contains a glossary of sea ice terms and references to additional information, which all serve as an excellent introduction. Data are also available from various collection methods for student interpretation.

  13. Sea Level rise contributors

    NSDL National Science Digital Library

    M.F. Meier

    This web page from the National Snow and Ice Data Center contains two related visualizations. The first visualization gives an estimate of the percent contribution to sea level change since the 1990s from three contributors - small glaciers and ice caps, the Greenland Ice Sheet and the Antarctic Ice Sheet. The second visualization shows the cumulative contribution to sea level from small glaciers and ice caps plotted with the annual global surface air temperature anomaly.

  14. Contemporary sea level rise.

    PubMed

    Cazenave, Anny; Llovel, William

    2010-01-01

    Measuring sea level change and understanding its causes has considerably improved in the recent years, essentially because new in situ and remote sensing observations have become available. Here we report on most recent results on contemporary sea level rise. We first present sea level observations from tide gauges over the twentieth century and from satellite altimetry since the early 1990s. We next discuss the most recent progress made in quantifying the processes causing sea level change on timescales ranging from years to decades, i.e., thermal expansion of the oceans, land ice mass loss, and land water-storage change. We show that for the 1993-2007 time span, the sum of climate-related contributions (2.85 +/- 0.35 mm year(-1)) is only slightly less than altimetry-based sea level rise (3.3 +/- 0.4 mm year(-1)): approximately 30% of the observed rate of rise is due to ocean thermal expansion and approximately 55% results from land ice melt. Recent acceleration in glacier melting and ice mass loss from the ice sheets increases the latter contribution up to 80% for the past five years. We also review the main causes of regional variability in sea level trends: The dominant contribution results from nonuniform changes in ocean thermal expansion. PMID:21141661

  15. Nucleotide sequence of the histone gene cluster in the coral acropora formosa (cnidaria; scleractinia): Features of histone gene structure and organization are common to diploblastic and triploblastic metazoans

    Microsoft Academic Search

    D. J. Miller; P. L. Harrison; T. J. Mahony; J. P. McMillan; A. Miles; D. M. Odorico; M. R. ten Lohuis

    1993-01-01

    We report the nucleotide sequence of the core histone gene cluster from the Cnidarian Acropora formosa. This is the first histone gene cluster to be sequenced from a diploblastic organism and the predicted amino acid sequences most resemble those of sea urchin equivalents. Each of the Cnidarian histone genes has two conserved regions 3' of the coding sequences and these

  16. Phylogenetics of Hydroidolina (Hydrozoa: Cnidaria)

    E-print Network

    Cartwright, Paulyn; Evans, Nathaniel M.; Dunn, Casey W.; Marques, Antonio C.; Miglietta, Maria Pia; Schuchert, Peter; Collins, Allen G.

    2008-05-08

    183131 MHNG INVE 34436 Oceaniidae Cordylophora caspia EU272556 EU272612 EU305472 Oceaniidae Corydendrium sp. EU272557 EU272613 KUNHM 2764 Oceaniidae Rhizogeton nudus EU272592 EU272635 AY787883 MHNG INVE 35757 Oceaniidae Turritopsis dohrnii EU272596 EU...272638 AY787889 MHNG INVE 29753 Oceaniidae Turritopsis nutricula EU305538 EU305504 EU305486 KUNHM 2817 Pandeidae Hydrichthys boycei EU272570 EU305496 EU448102 MHNG INVE 37417 Pandeidae Leuckartiara octona EU272573 EU272624 AM411421 Pandeidae Neoturris...

  17. The White Sea, Russia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Editor's Note: The caption below, published on May 10, 2001, is incorrect. According to Masha Vorontsova, director of the International Fund for Animal Welfare in Moscow, the situation with the seal pups in the White Sea is normal. There is no disaster and there never was. For more details, refer to the article entitled 'No Danger' on the New Scientist home page. The Earth Observatory regrets the earlier errant report. Original Caption According to the Russian Polar Research Institute for Fisheries and Oceanography, between 250,000 and 300,000 Greenland seal pups face death by starvation over the next two months due to a cruel trick by mother nature. The seals, most of them less than two months old, are trapped on ice sheets that remain locked in the White Sea, located near Archangel in Northern Russia. Typically, during the spring thaw the ice sheets break up and flow with the currents northward into the Barents Sea, the seals' spring feeding grounds. The seal pups hitch a ride on the ice floes, living on their own individual stores of fat until they arrive in the Barents Sea. Their mothers departed for the Barents Sea weeks ago. In a normal year, the seal pups' trip from the White Sea out to the Barents takes about six weeks and the seals have adapted to rely upon this mechanism of mother nature. During their yearly migration, the mother seals usually stay with their pups and feed them until their pelts turn from white to grey--a sign that the pups are mature enough to swim and feed themselves. Unfortunately, this year unusually strong northerly winds created a bottleneck of ice near the mouth of the white sea, thus blocking the flow of ice and trapping the pups. These true-color images of the White Sea were acquired by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra spacecraft. This image, taken May 2, 2000 that there is usually much less ice in the White Sea this time of year as most of it is typically en route to the Barents Sea.

  18. The Dead Sea

    NASA Technical Reports Server (NTRS)

    2006-01-01

    The Dead Sea is the lowest point on Earth at 418 meters below sea level, and also one of the saltiest bodies of water on Earth with a salinity of about 300 parts-per-thousand (nine times greater than ocean salinity). It is located on the border between Jordan and Israel, and is fed by the Jordan River. The Dead Sea is located in the Dead Sea Rift, formed as a result of the Arabian tectonic plate moving northward away from the African Plate. The mineral content of the Dead Sea is significantly different from that of ocean water, consisting of approximately 53% magnesium chloride, 37% potassium chloride and 8% sodium chloride. In the early part of the 20th century, the Dead Sea began to attract interest from chemists who deduced that the Sea was a natural deposit of potash and bromine. From the Dead Sea brine, Israel and Jordan produce 3.8 million tons potash, 200,000 tons elemental bromine, 45,000 tons caustic soda, 25, 000 tons magnesium metal, and sodium chloride. Both countries use extensive salt evaporation pans that have essentially diked the entire southern end of the Dead Sea.

    With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

    Size: 18.5 by 48.1 kilometers (11.5 by 29.8 miles) Location: 31.4 degrees North latitude, 35.4 degrees East longitude Orientation: North at top Image Data: ASTER bands 3, 2, and 1 Original Data Resolution: 15 meters (49.2 feet) Dates Acquired: May 3, 2005

  19. The relationship of the abundance and distribution of the sea anemone Bunodosoma cavernata bosc to variations in the physical environment in the rocky intertidal habitats of the north Texas coast

    E-print Network

    Anderson, Elise Marie

    1988-01-01

    on the upper surfaces as well. Below the algae are barnacles in a thin layer. Rarely do the barnacles form a solid layer with individuals touching. B. cavernata is patchily distributed, occurring in cracks and crevices formed by the sides of adjacent blocks.... harrisii and P. armatus are common under most larger rocks while C. vittatus and M. mercenaria occur infrequently around the bases of the granite. S 11 st di11s (thai ~ht ) ho f d gth barnacles. In the outer third of the site all permanent surfaces...

  20. Bioprospecting / Deep Sea Research

    NSDL National Science Digital Library

    The first portion of the radio broadcast discusses the relatively new field of bioprospecting, the exploration of the sea floor for novel compounds and processes that may have industrial or medical applications. Bioprospectors are trying to collect samples of deep-sea organisms which may yield new pharmaceutical compounds, as in the case of Conus magnus, a sea snail whose venom has yielded a painkiller 1000 times more potent than morphine. There is also discussion of who owns these resources and what can be done to protect them. This segment is 12 minutes in length. The second segment of the broadcast traces the history of undersea exploration, including methods of measuring ocean depth, the bathysphere used by William Beebe and Otis Barton, the modern Alvin submersible, and remotely operated vehicles. There is also discussion of the motives and inspiration for ocean exploration; the deep sea knowledge of whalers; and comparisons of deep sea research with space exploration. This segment is 34 minutes and 40 seconds in length.

  1. Late Holocene radiocarbon and aspartic acid racemization dating of deep-sea octocorals

    NASA Astrophysics Data System (ADS)

    Sherwood, Owen A.; Scott, David B.; Risk, Michael J.

    2006-06-01

    Primnoa resedaeformis is a deep-sea gorgonian coral with a two-part skeleton of calcite and gorgonin (a fibrillar protein), potentially containing long-term records of valuable paleo-environmental information. For various reasons, both radiocarbon and U/Th dating of these corals is problematic over the last few centuries. This paper explores aspartic acid racemization dating of the gorgonin fraction in modern and fossil specimens collected from the NW Atlantic Ocean. Radiocarbon dating of the fossil specimen indicates a lifespan of 700 ± 100 years, the longest yet documented for any octocoral. Gorgonin amino acid compositions were identical in the fossil and modern specimens, indicating resistance to organic diagenesis. Similar to bone collagen, the fibrillar protein of gorgonin may impose conformational constraints on the racemization of Asp at low temperatures. The rate of racemization of aspartic acid ( D/ L-Asp) was similar to previously published results from an 1800 year old anemone ( Gerardia). The age equation was: age (years BP 2000 AD) = [( D/ L - 0.020 (±.002))/.0011 (±.0001)] 2 ( r2 = 0.97, p < .001). The error in an age estimate calculated by D/ L-Asp was marginally better than that for 14C dating over the most recent 50-200 years, although the dating error may be improved by inclusion of more samples over a broader time range. These results suggest that D/ L-Asp dating may be useful in augmenting 14C dating in cases where 14C calibrations yield two or more intercept ages, or in screening samples for further 14C or U/Th dating.

  2. Microdistribution of faunal assemblages at deep-sea hydrothermal vents in the Southern Ocean.

    PubMed

    Marsh, Leigh; Copley, Jonathan T; Huvenne, Veerle A I; Linse, Katrin; Reid, William D K; Rogers, Alex D; Sweeting, Christopher J; Tyler, Paul A

    2012-01-01

    Chemosynthetic primary production by microbes supports abundant faunal assemblages at deep-sea hydrothermal vents, with zonation of invertebrate species typically occurring along physico-chemical gradients. Recently discovered vent fields on the East Scotia Ridge (ESR) in the Southern Ocean represent a new province of vent biogeography, but the spatial dynamics of their distinct fauna have yet to be elucidated. This study determines patterns of faunal zonation, species associations, and relationships between faunal microdistribution and hydrothermal activity in a vent field at a depth of 2,400 m on the ESR. Remotely operated vehicle (ROV) dives obtained high-definition imagery of three chimney structures with varying levels of hydrothermal activity, and a mosaic image of >250 m(2) of seafloor co-registered with temperature measurements. Analysis of faunal microdistribution within the mosaiced seafloor reveals a consistent pattern of faunal zonation with increasing distance from vent sources and peak temperatures. Assemblages closest to vent sources are visibly dominated by a new species of anomuran crab, Kiwa n. sp. (abundance >700 individuals m(-2)), followed by a peltospiroid gastropod (>1,500 individuals m(-2)), eolepadid barnacle (>1,500 individuals m(-2)), and carnivorous actinostolid anemone (>30 individuals m(-2)). Peripheral fauna are not dominated by a single taxon, but include predatory and scavenger taxa such as stichasterid seastars, pycnogonids and octopus. Variation in faunal microdistribution on chimneys with differing levels of activity suggests a possible successional sequence for vent fauna in this new biogeographic province. An increase in ?(34)S values of primary consumers with distance from vent sources, and variation in their ?(13)C values also indicate possible zonation of nutritional modes of the vent fauna. By using ROV videography to obtain a high-resolution representation of a vent environment over a greater extent than previous studies, these results provide a baseline for determining temporal change and investigations of processes structuring faunal assemblages at Southern Ocean vents. PMID:23144754

  3. Microdistribution of Faunal Assemblages at Deep-Sea Hydrothermal Vents in the Southern Ocean

    PubMed Central

    Marsh, Leigh; Copley, Jonathan T.; Huvenne, Veerle A. I.; Linse, Katrin; Reid, William D. K.; Rogers, Alex D.; Sweeting, Christopher J.; Tyler, Paul A.

    2012-01-01

    Chemosynthetic primary production by microbes supports abundant faunal assemblages at deep-sea hydrothermal vents, with zonation of invertebrate species typically occurring along physico-chemical gradients. Recently discovered vent fields on the East Scotia Ridge (ESR) in the Southern Ocean represent a new province of vent biogeography, but the spatial dynamics of their distinct fauna have yet to be elucidated. This study determines patterns of faunal zonation, species associations, and relationships between faunal microdistribution and hydrothermal activity in a vent field at a depth of 2,400 m on the ESR. Remotely operated vehicle (ROV) dives obtained high-definition imagery of three chimney structures with varying levels of hydrothermal activity, and a mosaic image of >250 m2 of seafloor co-registered with temperature measurements. Analysis of faunal microdistribution within the mosaiced seafloor reveals a consistent pattern of faunal zonation with increasing distance from vent sources and peak temperatures. Assemblages closest to vent sources are visibly dominated by a new species of anomuran crab, Kiwa n. sp. (abundance >700 individuals m?2), followed by a peltospiroid gastropod (>1,500 individuals m?2), eolepadid barnacle (>1,500 individuals m?2), and carnivorous actinostolid anemone (>30 individuals m?2). Peripheral fauna are not dominated by a single taxon, but include predatory and scavenger taxa such as stichasterid seastars, pycnogonids and octopus. Variation in faunal microdistribution on chimneys with differing levels of activity suggests a possible successional sequence for vent fauna in this new biogeographic province. An increase in ?34S values of primary consumers with distance from vent sources, and variation in their ?13C values also indicate possible zonation of nutritional modes of the vent fauna. By using ROV videography to obtain a high-resolution representation of a vent environment over a greater extent than previous studies, these results provide a baseline for determining temporal change and investigations of processes structuring faunal assemblages at Southern Ocean vents. PMID:23144754

  4. Total saponin from Anemone flaccida Fr. Schmidt abrogates osteoclast differentiation and bone resorption via the inhibition of RANKL-induced NF-?B, JNK and p38 MAPKs activation.

    PubMed

    Kong, Xiangying; Wu, Wenbin; Yang, Yue; Wan, Hongye; Li, Xiaomin; Zhong, Michun; Zhao, Hongyan; Su, Xiaohui; Jia, Shiwei; Ju, Dahong; Lin, Na

    2015-12-01

    Osteoclasts, bone-specialized multinucleated cells, are responsible for bone destructive diseases such as rheumatoid arthritis and osteoporosis. Natural plant-derived products have received substantial attention given their potential therapeutic and preventive activities against bone destructive diseases. In the present study, we investigated the effects of total saponin (TS) from Anemone flaccida Fr. Schmidt, on receptor activator of nuclear factor-?B ligand (RANKL)-induced in vitro osteoclast differentiation. We observed that TS concentration-dependently inhibited RANKL-induced osteoclast formation from RAW 264.7 cell and bone marrow-derived macrophages (BMMs), as well as decreased extent of actin ring formation and lacunar resorption. The RANKL-stimulated expression of osteoclast-related transcription factors were also diminished by TS. Moreover, TS blocked the RANKL-triggered TRAF6 expression, phosphorylation of mitogen-activated protein kinases (MAPKs) and IkB-?, and inhibited NF-?B p65 DNA binding activity. Furthermore, TS almost abrogated the nuclear factor of activated T cells (NFATc1) and c-Fos expression. Taken together, our results demonstrated that TS suppresses RANKL-induced osteoclast differentiation and inflammatory bone loss via the down-regulation of TRAF6 level, suppression of JNK and p38 MAPKs and NF-?B activation, and subsequent decreased expression of c-Fos and NFATc1. Therefore, TS may be a potential agent and needs to be more evaluated in vivo or in clinical trials to become a therapeutic for lytic bone diseases. PMID:25779147

  5. Geology of Barents Sea

    SciTech Connect

    Riis, F.; Vollset, J.

    1984-09-01

    The Barents Sea is situated on the continental shelf between Norway, the Spitsbergen Islands, and Novaya Zemlya. The main structural framework of the area was formed during the Caledonian and Hercynian orogenies, whereas the western parts were reactivated by the Kimmerian and Alpine orogenies. Because of the complex opening of the Greenland Norwegian Sea, important tertiary reactivation of Mesozoic normal faults occurred along southwest-northeast-trending systems of wrench faults. Owing to substantial erosion in the late Tertiary, the subsidence history and thermal development are more difficult to unravel in this area than in other places along the Norwegian Shelf. The erosion products were deposited in a huge sedimentary wedge extending onto the oceanic crust. The hydrocarbon discoveries in the Troms area in the southern part of the Barents Sea are encouraging for further exploration. However, the petroleum potential for large areas is not well known at this stage.

  6. SeaWeb

    NSDL National Science Digital Library

    SeaWeb is a nonprofit organization aimed at raising awareness of the ocean and marine life that play "a critical role in our everyday life and in the future of our planet." SeaWeb employs a team of professionals from biology, exploration, and various communication disciplines. The current campaigns include an effort to protect the declining Caspian Sea Sturgeon ("the source of most of the world's caviar"), an attempt to reduce overfishing of swordfish, and a report about the changes occurring in the world's oceans. This Web site is a robust source of information about many threats that are facing marine ecosystems, and an attempt to reduce the dangers by educating the public about the impacts of their behavior.

  7. New York Sea Grant

    NSDL National Science Digital Library

    The National Sea Grant program was established in 1966, and a few years later, the state of New York sponsored the program's first outpost. Currently, the New York Sea Grant (NYSG) is a cooperative program of the State University of New York (SUNY) and Cornell University. On the homepage, visitors can look over sections that include "Extension", "Research", "Education", "Publications", and "Theme Areas". The "Theme Areas" is a good place to start, as it features topical material on coastal processes and hazards, fisheries, and aquatic invasive species. Their helpful publication "Currents" is also worth a look, and it contains materials on grant opportunities, research materials, fact sheets, and public awareness programs. Moving on, the "Related Sites" area contains links to "Hot Topics" (topical news items related to the sea and such) and affiliated organizations.

  8. Caribbean Sea Level Network

    NASA Astrophysics Data System (ADS)

    von Hillebrandt-Andrade, C.; Crespo Jones, H.

    2012-12-01

    Over the past 500 years almost 100 tsunamis have been observed in the Caribbean and Western Atlantic, with at least 3510 people having lost their lives to this hazard since 1842. Furthermore, with the dramatic increase in population and infrastructure along the Caribbean coasts, today, millions of coastal residents, workers and visitors are vulnerable to tsunamis. The UNESCO IOC Intergovernmental Coordination Group for Tsunamis and other Coastal Hazards for the Caribbean and Adjacent Regions (CARIBE EWS) was established in 2005 to coordinate and advance the regional tsunami warning system. The CARIBE EWS focuses on four areas/working groups: (1) Monitoring and Warning, (2) Hazard and Risk Assessment, (3) Communication and (4) Education, Preparedness and Readiness. The sea level monitoring component is under Working Group 1. Although in the current system, it's the seismic data and information that generate the initial tsunami bulletins, it is the data from deep ocean buoys (DARTS) and the coastal sea level gauges that are critical for the actual detection and forecasting of tsunamis impact. Despite multiple efforts and investments in the installation of sea level stations in the region, in 2004 there were only a handful of sea level stations operational in the region (Puerto Rico, US Virgin Islands, Bermuda, Bahamas). Over the past 5 years there has been a steady increase in the number of stations operating in the Caribbean region. As of mid 2012 there were 7 DARTS and 37 coastal gauges with additional ones being installed or funded. In order to reach the goal of 100 operational coastal sea level stations in the Caribbean, the CARIBE EWS recognizes also the importance of maintaining the current stations. For this, a trained workforce in the region for the installation, operation and data analysis and quality control is considered to be critical. Since 2008, three training courses have been offered to the sea level station operators and data analysts. Other requirements and factors have been considered for the sustainability of the stations. The sea level stations have to potentially sustain very aggressive conditions of not only tsunamis, but on a more regular basis, hurricanes. Given the requirement that the data be available in near real time, for tsunami and other coastal hazard application, robust communication systems are also essential. For the local operator, the ability to be able to visualize the data is critical and tools like the IOC Sea level Monitoring Facility and the Tide Tool program are very useful. It has also been emphasized the need for these stations to serve multiple purposes. For climate and other research applications the data need to be archived, QC'd and analyzed. Increasing the user base for the sea level data has also been seen as an important goal to gain the local buy in; local weather and meteorological offices are considered as key stakeholders but for whom applications still need to be developed. The CARIBE EWS continues to look forward to working with other IOC partners including the Global Sea Level Observing System (GLOSS) and Sub-Commission for the Caribbean and Adjacent Regions (IOCARIBE)/GOOS, as well as with local, national and global sea level station operators and agencies for the development of a sustainable sea level network.

  9. Understanding Sea Level Changes

    NASA Technical Reports Server (NTRS)

    Chao, Benjamin F.

    2004-01-01

    Today more than 100 million people worldwide live on coastlines within one meter of mean sea level; any short-term or long-term sea level change relative to vertical ground motion is of great societal and economic concern. As palm-environment and historical data have clearly indicated the existence and prevalence of such changes in the past, new scientific information regarding to the nature and causes and a prediction capability are of utmost importance for the future. The 10-20 cm global sea-level rise recorded over the last century has been broadly attributed to two effects: (1) the steric effect (thermal expansion and salinity-density compensation of sea water) following global climate; (2) mass-budget changes due to a number of competing geophysical and hydrological processes in the Earth-atmosphere-hydrosphere-cryosphere system, including water exchange from polar ice sheets and mountain glaciers to the ocean, atmospheric water vapor and land hydrological variations, and anthropogenic effects such as water impoundment in artificial reservoirs and extraction of groundwater, all superimposed on the vertical motions of solid Earth due to tectonics, rebound of the mantle from past and present deglaciation, and other local ground motions. As remote-sensing tools, a number of space geodetic measurements of sea surface topography (e.g., TOPEX/Poseidon, Jason), ice mass (e.g., ICESat), time-variable gravity (e.g. GRACE), and ground motions (SLR, VLBI, GPS, InSAR, Laser altimetry, etc.) become directly relevant. Understanding sea level changes "anywhere, anytime" in a well-defined terrestrial reference frame in terms of climate change and interactions among ice masses, oceans, and the solid Earth, and being able to predict them, emerge as one of the scientific challenges in the Solid Earth Science Working Group (SESWG, 2003) conclusions.

  10. RADIOCARBON RESERVOIR AGES IN THE MEDITERRANEAN SEA AND BLACK SEA

    Microsoft Academic Search

    Nadine Tisnerat; Franck Bassinot

    We measured apparent marine radiocarbon ages for the Mediterranean Sea, Black Sea, and Red Sea by accel- erator mass spectrometry radiocarbon analyses of 26 modern, pre-bomb mollusk shells collected living between AD 1837 and 1950. The marine reservoir (R(t)) ages were estimated at some 390 ± 85 yr BP, 415 ± 90 yr BP and 440 ± 40 yr BP,

  11. Deep Drilling at Sea

    NSDL National Science Digital Library

    Kate Ramsayer

    This Science News for Kids article provides an image-rich overview of a deep-sea drilling project off the coast of British Columbia. The article guides students through the exploration, explaining how deep sediment cores are taken, what researchers find in the cores, and details of what life is like on a research ship. It features links to an online poll, an opportunity for students to submit comments, a deep-sea drilling word find, and links to supplementary reading questions and related sites.

  12. Melting Sea Ice

    NSDL National Science Digital Library

    WGBH Educational Foundation Teachers' Domain

    This activity uses a mix of multimedia resources and hands-on activities to support a storyline of investigation into melting sea ice. The lesson begins with a group viewing of a video designed to get students to consider both the local and global effects of climate change. The class then divides into small groups for inquiry activities on related topics followed by a presentation of the findings to the entire class. A final class discussion reveals a more complex understanding of both the local and global impacts of melting sea ice.

  13. Lighting Up the Sea

    NSDL National Science Digital Library

    National Geographic Xpeditions

    This National Geographic lesson plan explores bioluminescent organisms in the sea. In this activity, students explore the benefits of bioluminescence by conducting a simulation and viewing pictures of bioluminescent marine animals on the Web. The conclusion of the activity entails students pretending to be deep-sea divers and writing journal entries about their impressions of a bioluminescent animal they have encountered. In addition to a detailed procedure, the lesson plan includes suggestions for assessment, ideas for extending the lesson, and links to related websites.

  14. Melting Sea Ice

    NSDL National Science Digital Library

    2007-01-01

    This activity uses a mix of multimedia resources and hands-on activities to support a storyline of investigation into melting sea ice. The lesson begins with a group viewing of a video designed to get students to consider both the local and global effects of climate change. The class then divides into small groups for inquiry activities on related topics followed by a presentation of the findings to the entire class. A final class discussion reveals a more complex understanding of both the local and global impacts of melting sea ice.

  15. National Sea Grant Library

    NSDL National Science Digital Library

    This is the website for the only facility housing a complete collection of Sea Grant funded work. An archive and lending library for reprints, books, reports, maps, newsletters, handbooks, videos, CD-roms and computer programs regarding: oceanography; marine education; aquaculture; fisheries; limnology; coastal zone management; marine recreation and law. Lends documents worldwide, aiding scientists, teachers, students, fishermen and others in research and study. Bibliographic database is searchable from the website, where users may obtain citations, abstracts and access to over 20,000 downloadable texts of Sea Grant publications.

  16. Spectacled Eiders Wintering in Northern Bering Sea

    USGS Multimedia Gallery

    Large flock of Spectacled Eiders aggregated in a sea ice lead and on sea ice in the northern Bering Sea, south of St. Lawrence Island, Alaska.  Aerial photograph from a helicopter deployed from the USCG Cutter Polar Sea....

  17. Seafloor Control on Sea Ice

    NASA Technical Reports Server (NTRS)

    Nghiem, S. V.; Clemente-Colon, P.; Rigor, I. G.; Hall, D. K.; Neumann, G.

    2011-01-01

    The seafloor has a profound role in Arctic sea ice formation and seasonal evolution. Ocean bathymetry controls the distribution and mixing of warm and cold waters, which may originate from different sources, thereby dictating the pattern of sea ice on the ocean surface. Sea ice dynamics, forced by surface winds, are also guided by seafloor features in preferential directions. Here, satellite mapping of sea ice together with buoy measurements are used to reveal the bathymetric control on sea ice growth and dynamics. Bathymetric effects on sea ice formation are clearly observed in the conformation between sea ice patterns and bathymetric characteristics in the peripheral seas. Beyond local features, bathymetric control appears over extensive ice-prone regions across the Arctic Ocean. The large-scale conformation between bathymetry and patterns of different synoptic sea ice classes, including seasonal and perennial sea ice, is identified. An implication of the bathymetric influence is that the maximum extent of the total sea ice cover is relatively stable, as observed by scatterometer data in the decade of the 2000s, while the minimum ice extent has decreased drastically. Because of the geologic control, the sea ice cover can expand only as far as it reaches the seashore, the continental shelf break, or other pronounced bathymetric features in the peripheral seas. Since the seafloor does not change significantly for decades or centuries, sea ice patterns can be recurrent around certain bathymetric features, which, once identified, may help improve short-term forecast and seasonal outlook of the sea ice cover. Moreover, the seafloor can indirectly influence cloud cover by its control on sea ice distribution, which differentially modulates the latent heat flux through ice covered and open water areas.

  18. National Sea Grant Educators Network

    NSDL National Science Digital Library

    Compilation of Sea Grant marine education resources. Site includes the latest news, a pdf file discussing Sea Grant education initiatives, links to all Sea Grant Education websites, several teaching and learning resources, and several interactive classroom activities. An excellent site to begin preparations for a marine science or oceanography course.

  19. 3, 637669, 2006 Mediterranean Sea

    E-print Network

    Paris-Sud XI, Université de

    OSD 3, 637­669, 2006 Central Mediterranean Sea forecast S. Natale et al. Title Page Abstract Mediterranean Sea forecast: effects of high-resolution atmospheric forcings S. Natale1 , R. Sorgente2 , S­669, 2006 Central Mediterranean Sea forecast S. Natale et al. Title Page Abstract Introduction Conclusions

  20. Tides & Currents: Sea Level Trends

    NSDL National Science Digital Library

    2010-01-01

    The Center for Operational Oceanographic Products and Services has been measuring sea level for over 150 years. This resource illustrates regional trends in sea level, with arrows representing the direction and magnitude of change including national and global stations. Impacts on changing sea levels in relation to atmospheric and oceanic processes as well as other Earth systems are explained and supported with educations resources.

  1. Sea Level : Frequently Asked Questions and Answers

    NSDL National Science Digital Library

    2007-12-12

    Visitors can find answers to frequently asked questions regarding sea level and sea level changes. Topics addressed include how mean sea level is defined, how much sea level would rise if all the worlds ice were to melt, differences in sea level between oceans and at different latitudes, the meaning of altitude above sea level, and others.

  2. Steller Sea Lion

    NSDL National Science Digital Library

    A comprehensive site featuring the threatened Steller Sea Lion. Site includes information on its critical habitat, protection measures, distribution information, and much more. Explore the Literature, Presentations, and Images section for an abundance of information from conferences, workshops, and research. Site features a wealth of photographs and video, as well as contact information for the program.

  3. Sea Turtles Coloring Book

    NSDL National Science Digital Library

    Using excellent line drawings, this coloring book provides great background information about sea turtles in both English and Spanish. Species profiles, biology and life cycle, ecology, distribution, uses and threats, like fishing and habitat destruction, are covered. Measures for protection and conservation are introduced.

  4. Farming the Sea

    ERIC Educational Resources Information Center

    Morgan, William

    1971-01-01

    Florida has initiated a training program in an entirely new dimension--Sea Farming. Presented is a description of the vocational agriculture program designed to teach propagation, cultivation, harvesting, marketing, and conservation practices related to production of oysters, shrimp, scallops, crabs, and fin fishes. (Editor/GB)

  5. Labour Flexibilization at Sea

    Microsoft Academic Search

    Christine B. N. Chin

    2008-01-01

    Cruise line employment of men and women contract seafarers from all over the world since the late twentieth century has produced what is called multinational or ‘mini UN’ crew on board large modern cruise ships. This phenomenon is encouraged by open ship registries that legally endorse and affirm the flexibilization of labour at sea. Labour flexibilization processes, however, are not

  6. Redlands Institute: Salton Sea

    NSDL National Science Digital Library

    The Salton Sea Database Program (SSDP) at the University of Redlands, Redlands Institute (RI) was a project administered by the U.S. Environmental Protection Agency (EPA), Center for Special Programs. The purpose behind the SSDP was to bring a wide range of data management and analysis tools and professionals "to support multi-disciplinary and coordinated decision-making across all the professional and scientific teams and stakeholders involved in the restoration of California's largest inland body of water, the Salton Sea." Part of their outreach work includes this fine website, which includes sections titled "Ecological Issues", "Data & Research", and "Exploring the Area". First-time visitors may want to start by clicking on the "Ecological Issues" area. Here they can learn about the science of the area, the contemporary issues facing the survival of the Salton Sea, and some of the proposed solutions to restore the Sea. Journalists and scientists will appreciate the "Data & Research" area, as it features digital maps of the area, GIS data, public policy documents, and an image database. The casual traveler will enjoy the "Exploring the Area" section, and here they will find information about current weather conditions, fishing reports, and California State park materials.

  7. Solomon's Sea and [Pi

    ERIC Educational Resources Information Center

    Simoson, Andrew J.

    2009-01-01

    This paper is a whimsical survey of the various explanations which might account for the biblical passage in I Kings 7:23 that describes a round object--a bronze basin called Solomon's Sea--as having diameter ten cubits and circumference thirty cubits. Can the biblical pi be any number other than 3? We offer seven different perspectives on this…

  8. Whither Arctic Sea Ice?

    NSDL National Science Digital Library

    Betsy Youngman

    In this activity students work with real datasets to investigate a real situation regarding disappearing Arctic sea ice. The case study has students working side-by-side with a scientist from the National Snow and Ice Data Center and an Inuit community in Manitoba.

  9. SeaDiscovery.com

    NSDL National Science Digital Library

    SeaDiscovery.com is an online source for "underwater tech and ocean science news." The site presents not only news, but information about maritime technology employment which includes featured jobs and resumes. It also allows access to the Maritime Technology Reporter magazine and provides links to a number of important directories.

  10. Classroom of the Sea

    NSDL National Science Digital Library

    Denise Monte

    2000-03-01

    Although most students do not have the opportunity to conduct in situ research projects until college, the Classroom of the Sea program at the American School for the Deaf (ASD) provides an unusual opportunity for students to work directly with scientists

  11. Sea Grant's Education Mission.

    ERIC Educational Resources Information Center

    Sherman, Douglas

    1998-01-01

    Considers the status of the education agenda of the Sea Grant Program as it turns 30. Projects described include Operation Pathfinder, which aims to educate minority teachers and/or teachers of minority students. Also described are a program in which seafood processors and resellers are trained in safety and health areas, and programs to train…

  12. Black Sea Battle

    NSDL National Science Digital Library

    Story of the invasion of jellyfish into the Black Sea and the resulting affects on the native fish population. An excellent introduction into introduced species and their effects on an ecosystem. Site features an abundance of information on alien species and the delicacy that goes into eradicating them. Also links to additional non-traditional science-related news events.

  13. Egyptian Sea Cave

    ERIC Educational Resources Information Center

    Journal of College Science Teaching, 2005

    2005-01-01

    This brief article describes an archaeological expedition to the Red Sea coast area of Egypt in 2004. Kathryn Bard, an associate professor of archaeology at Boston University, along with her team, discovered the well-preserved cedar timbers of an ancient Egyptian seafaring vessel near the entrance to a large man-made cave. Limestone tablets with…

  14. Solar Sea Power

    ERIC Educational Resources Information Center

    Zener, Clarence

    1976-01-01

    In their preoccupation with highly complex new energy systems, scientists and statesmen may be overlooking the possibilities of Ocean Thermal Energy Conversion (OTEC). That is the view of a Carnegie-Mellon University physicist who is in the forefront of solar sea power investigation. (Author/BT)

  15. Autophagy at sea.

    PubMed

    Martens, Sascha; Rusten, Tor Erik; Kraft, Claudine

    2013-09-01

    The 3rd EMBO Conference on, "Autophagy: Molecular mechanism, physiology and pathology" organized by Anne Simonsen and Sharon Tooze, was held in May 2013 on a sea cruise along the Norwegian coastline from Bergen to Tromsø. Researchers from all corners of the world presented work covering autophagosome biogenesis, physiological regulation of autophagy, selective autophagy and disease. PMID:23917436

  16. Under the Sea

    NSDL National Science Digital Library

    This activity integrates art and science as students use books and other sources to learn more about the creatures that live in the ocean. Once they have learned about various sea creatures and their habitats, they will construct an undersea environment in their classroom.

  17. Sea Surface Temperature Climatology

    NSDL National Science Digital Library

    Earth Education Online

    This interactive animation shows global sea surface temperature averages for the same months over a number of years. Click on the map to see values for a particular month. This takes leads to a viewer that allows users to manipulate the figure, zooming in to a particular spot, altering the size, or changing the format.

  18. Harvesting the Sea.

    ERIC Educational Resources Information Center

    Markle, Sandra

    1989-01-01

    Information on commercial fishing is provided, and a board game is described which requires students to watch for ocean signs of good fishing, choose equipment to catch specific types of fish, and consider effects of weather on working at sea. A reproducible copy of the game, with instructions, is included. (IAH)

  19. Rising Sea Levels

    NSDL National Science Digital Library

    NBC Learn

    2010-10-07

    In the past century, as the climate has warmed, sea level rise has accelerated. Scientists predict it will only increase, and they're studying changes in the ocean and land to better understand how and why the water is rising. "Changing Planet" is produced in partnership with the National Science Foundation.

  20. Sea Level Viewer

    NSDL National Science Digital Library

    This interactive program focuses on the role of sea level in climate change. Sections include an overview and a list of relevant NASA satellite missions and their objectives. A third section, entitled Global View, covers the following 5 topics: Latest View, Large El Niño, Hurricane Katrina, Indian Ocean Tsunami, and La Niña.