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1

Latitudinal diversity of sea anemones (Cnidaria: Actiniaria).  

PubMed

We sought to determine if the global distribution of sea anemones (cnidarian order Actiniaria) conforms to the classic pattern of biogeography--taxon richness at the equator with attenuation toward the poles--a pattern that is derived almost entirely from data on terrestrial plants and animals. We plotted the empirical distribution of species occurrences in 10° bands of latitude based on published information, then, using the Chao2 statistic, inferred the completeness of that inventory. We found the greatest species richness of sea anemones at 30-40° N and S, with lower numbers at tropical latitudes and the fewest species in polar areas. The Chao2 statistic allowed us to infer that the richness pattern we found is not due to particularly poor knowledge of tropical sea anemones. No 10° band of latitude has less than 60% of the theoretical number of species known, but for only about half of them could we reject the null hypothesis (P = 0.05) that information is complete; anemone diversity is best documented at high latitudes. We infer that the 1089 valid species currently known constitute about 70% of the theoretical total of about 1500 species of Actiniaria. The distribution pattern of sea anemone species resembles that of planktonic foraminiferans and benthic marine algae, although planktonic bacteria, marine bivalves, and shallow and deep scleractinian corals show the terrestrial pattern of equatorial richness attenuating with latitude. Sea anemone species richness is complementary to that of scleractinian corals at many scales; our findings affirm it at the global scale. PMID:23677974

Fautin, Daphne Gail; Malarky, Lacey; Soberón, Jorge

2013-04-01

2

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

Microsoft Academic Search

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

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

2004-01-01

3

Sea anemones (Cnidaria, Anthozoa, Actiniaria) from coral reefs in the southern Gulf of Mexico.  

PubMed

Seven sea anemone species from coral reefs in the southern Gulf of Mexico are taxonomically diagnosed and images from living specimens including external and internal features, and cnidae are provided. Furthermore, the known distribution ranges from another 10 species are extended. No species records of sea anemones have been previously published in the primary scientific literature for coral reefs in the southern Gulf of Mexico and thus, this study represents the first inventory for the local actiniarian fauna. PMID:24146599

González-Muñoz, Ricardo; Simões, Nuno; Tello-Musi, José Luis; Rodríguez, Estefanía

2013-01-01

4

Sea anemones (Cnidaria, Anthozoa, Actiniaria) from coral reefs in the southern Gulf of Mexico  

PubMed Central

Abstract Seven sea anemone species from coral reefs in the southern Gulf of Mexico are taxonomically diagnosed and images from living specimens including external and internal features, and cnidae are provided. Furthermore, the known distribution ranges from another 10 species are extended. No species records of sea anemones have been previously published in the primary scientific literature for coral reefs in the southern Gulf of Mexico and thus, this study represents the first inventory for the local actiniarian fauna.

Gonzalez-Munoz, Ricardo; Simoes, Nuno; Tello-Musi, Jose Luis; Rodriguez, Estefania

2013-01-01

5

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

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

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

6

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

USGS Publications Warehouse

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.

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

2004-01-01

7

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

NASA Astrophysics Data System (ADS)

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.

Sanamyan, Nadya; Sanamyan, Karen

2013-02-01

8

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

Microsoft Academic Search

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

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

2009-01-01

9

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

Microsoft Academic Search

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

Ha-Rim Cha; Robert W. Buddemeier; Daphne G. Fautin; Peder Sandhei

2004-01-01

10

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

Microsoft Academic Search

Using environmental data and the geospatial clustering tools LOICZView and DISCO, we empirically tested the postulated existence\\u000a and boundaries of four biogeographic regions in the southern part of the Korean peninsula. Environmental variables used included\\u000a wind speed, sea surface temperature (SST), salinity, tidal amplitude, and the chlorophyll spectral signal. Our analysis confirmed\\u000a the existence of four biogeographic regions, but the

Ha-Rim Cha; Daphne G. Fautin; Robert W. Buddemeier; Peder Sandhei

11

Sea Anemone Genome Reveals Ancestral Eumetazoan Gene Repertoire and Genomic Organization  

Microsoft Academic Search

Sea anemones are seemingly primitive animals that, along with corals, jellyfish, and hydras, constitute the oldest eumetazoan phylum, the Cnidaria. Here, we report a comparative analysis of the draft genome of an emerging cnidarian model, the starlet sea anemone Nematostella vectensis. The sea anemone genome is complex, with a gene repertoire, exon-intron structure, and large-scale gene linkage more similar to

Nicholas H. Putnam; Mansi Srivastava; Uffe Hellsten; Bill Dirks; Jarrod Chapman; Asaf Salamov; Astrid Terry; Harris Shapiro; Erika Lindquist; Vladimir V. Kapitonov; Jerzy Jurka; Grigory Genikhovich; Igor V. Grigoriev; Susan M. Lucas; Robert E. Steele; John R. Finnerty; Ulrich Technau; Mark Q. Martindale; Daniel S. Rokhsar

2007-01-01

12

Hidden among Sea Anemones: The First Comprehensive Phylogenetic Reconstruction of the Order Actiniaria (Cnidaria, Anthozoa, Hexacorallia) Reveals a Novel Group of Hexacorals.  

PubMed

Sea anemones (order Actiniaria) are among the most diverse and successful members of the anthozoan subclass Hexacorallia, occupying benthic marine habitats across all depths and latitudes. Actiniaria comprises approximately 1,200 species of solitary and skeleton-less polyps and lacks any anatomical synapomorphy. Although monophyly is anticipated based on higher-level molecular phylogenies of Cnidaria, to date, monophyly has not been explicitly tested and at least some hypotheses on the diversification of Hexacorallia have suggested that actiniarians are para- or poly-phyletic. Published phylogenies have demonstrated the inadequacy of existing morphological-based classifications within Actiniaria. Superfamilial groups and most families and genera that have been rigorously studied are not monophyletic, indicating conflict with the current hierarchical classification. We test the monophyly of Actiniaria using two nuclear and three mitochondrial genes with multiple analytical methods. These analyses are the first to include representatives of all three currently-recognized suborders within Actiniaria. We do not recover Actiniaria as a monophyletic clade: the deep-sea anemone Boloceroides daphneae, previously included within the infraorder Boloceroidaria, is resolved outside of Actiniaria in several of the analyses. We erect a new genus and family for B. daphneae, and rank this taxon incerti ordinis. Based on our comprehensive phylogeny, we propose a new formal higher-level classification for Actiniaria composed of only two suborders, Anenthemonae and Enthemonae. Suborder Anenthemonae includes actiniarians with a unique arrangement of mesenteries (members of Edwardsiidae and former suborder Endocoelantheae). Suborder Enthemonae includes actiniarians with the typical arrangement of mesenteries for actiniarians (members of former suborders Protantheae, Ptychodacteae, and Nynantheae and subgroups therein). We also erect subgroups within these two newly-erected suborders. Although some relationships among these newly-defined groups are still ambiguous, morphological and molecular results are consistent enough to proceed with a new higher-level classification and to discuss the putative functional and evolutionary significance of several morphological attributes within Actiniaria. PMID:24806477

Rodríguez, Estefanía; Barbeitos, Marcos S; Brugler, Mercer R; Crowley, Louise M; Grajales, Alejandro; Gusmão, Luciana; Häussermann, Verena; Reft, Abigail; Daly, Marymegan

2014-01-01

13

Hidden among Sea Anemones: The First Comprehensive Phylogenetic Reconstruction of the Order Actiniaria (Cnidaria, Anthozoa, Hexacorallia) Reveals a Novel Group of Hexacorals  

PubMed Central

Sea anemones (order Actiniaria) are among the most diverse and successful members of the anthozoan subclass Hexacorallia, occupying benthic marine habitats across all depths and latitudes. Actiniaria comprises approximately 1,200 species of solitary and skeleton-less polyps and lacks any anatomical synapomorphy. Although monophyly is anticipated based on higher-level molecular phylogenies of Cnidaria, to date, monophyly has not been explicitly tested and at least some hypotheses on the diversification of Hexacorallia have suggested that actiniarians are para- or poly-phyletic. Published phylogenies have demonstrated the inadequacy of existing morphological-based classifications within Actiniaria. Superfamilial groups and most families and genera that have been rigorously studied are not monophyletic, indicating conflict with the current hierarchical classification. We test the monophyly of Actiniaria using two nuclear and three mitochondrial genes with multiple analytical methods. These analyses are the first to include representatives of all three currently-recognized suborders within Actiniaria. We do not recover Actiniaria as a monophyletic clade: the deep-sea anemone Boloceroides daphneae, previously included within the infraorder Boloceroidaria, is resolved outside of Actiniaria in several of the analyses. We erect a new genus and family for B. daphneae, and rank this taxon incerti ordinis. Based on our comprehensive phylogeny, we propose a new formal higher-level classification for Actiniaria composed of only two suborders, Anenthemonae and Enthemonae. Suborder Anenthemonae includes actiniarians with a unique arrangement of mesenteries (members of Edwardsiidae and former suborder Endocoelantheae). Suborder Enthemonae includes actiniarians with the typical arrangement of mesenteries for actiniarians (members of former suborders Protantheae, Ptychodacteae, and Nynantheae and subgroups therein). We also erect subgroups within these two newly-erected suborders. Although some relationships among these newly-defined groups are still ambiguous, morphological and molecular results are consistent enough to proceed with a new higher-level classification and to discuss the putative functional and evolutionary significance of several morphological attributes within Actiniaria.

Rodriguez, Estefania; Barbeitos, Marcos S.; Brugler, Mercer R.; Crowley, Louise M.; Grajales, Alejandro; Gusmao, Luciana; Haussermann, Verena; Reft, Abigail; Daly, Marymegan

2014-01-01

14

Sea Anemone: Investigations.  

ERIC Educational Resources Information Center

Several investigations can be undertaken with live sea anemones. A sea anemone's feeding response, fighting power, color, and symbiotic relationships to other invertebrates (such as a marine hermit crab) can be investigated in the high school classroom. Background information and laboratory procedures are provided. (Author/JN)

Hunt, John D.

1982-01-01

15

Phylogenetic Relationships among Deep-Sea and Chemosynthetic Sea Anemones: Actinoscyphiidae and Actinostolidae (Actiniaria: Mesomyaria)  

Microsoft Academic Search

Sea anemones (Cnidaria, Actiniaria) are present in all marine ecosystems, including chemosynthetic environments. The high level of endemicity of sea anemones in chemosynthetic environments and the taxonomic confusion in many of the groups to which these animals belong makes their systematic relationships obscure. We use five molecular markers to explore the phylogenetic relationships of the superfamily Mesomyaria, which includes most

Estefanía Rodríguez; Marymegan Daly; Sharyn Jane Goldstien

2010-01-01

16

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

Microsoft Academic Search

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

Glen M. Watson; Patricia Mire

2004-01-01

17

Sea anemone exposed at low tide  

NSDL National Science Digital Library

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.

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

2007-01-05

18

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

Microsoft Academic Search

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

Glen M. Watson; Patricia Mire

19

Origins of Bilateral Symmetry: Hox and Dpp Expression in a Sea Anemone  

Microsoft Academic Search

Over 99% of modern animals are members of the evolutionary lineage Bilateria. The evolutionary success of Bilateria is credited partly to the origin of bilateral symmetry. Although animals of the phylum Cnidaria are not within the Bilateria, some representatives, such as the sea anemone Nematostella vectensis, exhibit bilateral symmetry. We show that Nematostella uses homologous genes to achieve bilateral symmetry:

John R. Finnerty; Kevin Pang; Pat Burton; Dave Paulson; Mark Q. Martindale

2004-01-01

20

Phylogenetic Relationships among Deep-Sea and Chemosynthetic Sea Anemones: Actinoscyphiidae and Actinostolidae (Actiniaria: Mesomyaria)  

PubMed Central

Sea anemones (Cnidaria, Actiniaria) are present in all marine ecosystems, including chemosynthetic environments. The high level of endemicity of sea anemones in chemosynthetic environments and the taxonomic confusion in many of the groups to which these animals belong makes their systematic relationships obscure. We use five molecular markers to explore the phylogenetic relationships of the superfamily Mesomyaria, which includes most of the species that live in chemosynthetic, deep-sea, and polar sea habitats and to test the monophyly of the recently defined clades Actinostolina and Chemosynthina. We found that sea anemones of chemosynthetic environments derive from at least two different lineages: one lineage including acontiate deep-sea taxa and the other primarily encompassing shallow-water taxa.

Rodriguez, Estefania; Daly, Marymegan

2010-01-01

21

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

PubMed Central

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.

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

2012-01-01

22

Sea anemones possess dynamic mitogenome structures.  

PubMed

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

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

2014-06-01

23

Sea Anemone Toxins Affecting Potassium Channels  

NASA Astrophysics Data System (ADS)

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.

Diochot, Sylvie; Lazdunski, Michel

24

Reproduction in the Aggregating Sea Anemone, Anthopleura elegantissima  

Microsoft Academic Search

From a sample of 240 specimens of the aggregating sea anemone, Anthopleura elegantissima, collected a few miles north of the Golden Gate, males and females were shown to be distributed as unisexual aggregations on the rocks. The degree of gonadal development was measured by taking the gonad index (the ratio of volume of gonads to wet weight of anemone) every

CHARLES E. FORD

25

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

PubMed

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

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

2013-01-01

26

Cytolytic peptide and protein toxins from sea anemones (Anthozoa: Actiniaria)  

Microsoft Academic Search

More than 32 species of sea anemones have been reported to produce lethal cytolytic peptides and proteins. Based on their primary structure and functional properties, cytolysins have been classified into four polypeptide groups. Group I consists of 5–8kDa peptides, represented by those from the sea anemones Tealia felina and Radianthus macrodactylus. These peptides form pores in phosphatidylcholine containing membranes. The

Gregor Anderluh; Peter Ma?ek

2002-01-01

27

Characterizing the spatiotemporal expression of RNAs and proteins in the starlet sea anemone, Nematostella vectensis.  

PubMed

In an effort to reconstruct the early evolution of animal genes and proteins, there is an increasing focus on basal animal lineages such as sponges, cnidarians, ctenophores and placozoans. Among the basal animals, the starlet sea anemone Nematostella vectensis (phylum Cnidaria) has emerged as a leading laboratory model organism partly because it is well suited to experimental techniques for monitoring and manipulating gene expression. Here we describe protocols adapted for use in Nematostella to characterize the expression of RNAs by in situ hybridization using either chromogenic or fluorescence immunohistochemistry (?1 week), as well as to characterize protein expression by whole-mount immunofluorescence (?3 d). We also provide a protocol for labeling cnidocytes (?3 h), the phylum-specific sensory-effector cell type that performs a variety of functions in cnidarians, including the delivery of their venomous sting. PMID:23579779

Wolenski, Francis S; Layden, Michael J; Martindale, Mark Q; Gilmore, Thomas D; Finnerty, John R

2013-05-01

28

INTRASPECIFIC AGGRESSION AND ITS EFFECT ON THE DISTRIBUTION OF ANTHOPLEURA ELEGANTISSIMA AND SOME RELATED SEA ANEMONES  

Microsoft Academic Search

Contiguous aggregations of the west coast sea anemone Anthopleura elegan tissima are composed of individuals from a single clone, the products of asexual reproduction. In the field, adjacent clones of anemones are observed to be iso lated from each other by anemone-free spaces ; and in the laboratory a group of anemones of mixed clonal origins will reaggregate into isolated

LISBETH FRANCIS

1973-01-01

29

High In Situ Repeatability of Behaviour Indicates Animal Personality in the Beadlet Anemone Actinia equina (Cnidaria)  

PubMed Central

‘Animal personality’ means that individuals differ from one another in either single behaviours or suites of related behaviours in a way that is consistent over time. It is usually assumed that such consistent individual differences in behaviour are driven by variation in how individuals respond to information about their environment, rather than by differences in external factors such as variation in microhabitat. Since behavioural variation is ubiquitous in nature we might expect ‘animal personality’ to be present in diverse taxa, including animals with relatively simple nervous systems. We investigated in situ startle responses in a sea anemone, Actinia equina, to determine whether personalities might be present in this example of an animal with a simple nervous system. We found very high levels of repeatability among individuals that were re-identified in the same locations over a three week sampling period. In a subset of the data, where we used tide-pool temperature measurements to control for a key element of variation in microhabitat, these high levels of repeatability remained. Although a range of other consistent differences in micro-habitat features could have contributed to consistent differences between the behaviour of individuals, these data suggest the presence of animal personality in A. equina. Rather than being restricted to certain groups, personality may be a general feature of animals and may be particularly pronounced in species with simple nervous systems.

Briffa, Mark; Greenaway, Julie

2011-01-01

30

The nature of the symbiosis between Indo-Pacific anemone fishes and sea anemones  

Microsoft Academic Search

Under the general heading of symbiosis, defined originally to mean a “living together” of two dissimilar species, exist the sub-categories of mutualism (where both partners benefit), commensalism (where one partner benefits and the other is neutral) and parasitism (where one partner benefits and the other is harmed). The sea anemone-fish (mainly of the genus Amphiprion) symbiosis has generally been considered

R. N. Mariscal

1970-01-01

31

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

PubMed Central

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.

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

2013-01-01

32

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

PubMed

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

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

33

Clone-Specific Cellular Recognition in a Sea Anemone  

Microsoft Academic Search

A highly specific cellular recognition system, capable of distinguishing between syngeneic and allogeneic tissue, exists in Anthopleura elegantissima, a sea anemone that lives in clonal colonies and attacks foreign clones. During the attack, specialized surface protrusions (acrorhagi) are used for stinging. The recognition process was studied by presenting various tissues to the surface of inflated acrorhagi and observing whether nematocyst

Roger Lubbock

1980-01-01

34

Feeding factors for the sea anemone Anthopleura midorii  

Microsoft Academic Search

The carnivorous feeding behavior of the sea anemone Anthopleura midorii was found to be a sequence of successive feeding motions, which consisted of several separate actions: (1) tentaculation on any solid matter; (2) retention of prey by tentacles; (3) mouth opening; (4) ingestion of food; (5) digestion of food; (6) extrusion of indigestible waste material. Hot water extract of a

Y. Nagai; S. Nagai

1973-01-01

35

Adhesion in the sea anemones actinia equina L. and metridium senile (L.)  

Microsoft Academic Search

The adhesion of the sea anemones Actinia equina and Metridium senile was tested on a variety of surfaces, and the force required to remove the anemones related to the surface area of the pedal disc in contact with the substratum. In common with many other marine organisms, anemones were more strongly attached to rough surfaces and those with high free

G. A. Young; A. B. Yule; G. Walker

1988-01-01

36

Development and Characterization of Sea Anemones as Bioindicators of Offshore Resource Exploitation and Environmental Impact.  

National Technical Information Service (NTIS)

Five species of sea anemones were characterized as potential sentinels of marine pollution. Proteins of 50-60 KDa were recognized by antibodies (Ab) raised to fish or mammalian cytochromnes P450 (CYP) in microsomes of all sea anemones. Microsomal ethoxyre...

G. W. Winston L. M. Heffernan

1999-01-01

37

Report of Stingings by the Sea Anemone 'Triactis producta' Klunzinger from Red Sea.  

National Technical Information Service (NTIS)

The sea anemone Triactis producta Klunzinger is an inhabitant of the Red Sea. A clinical case history of a stinging by T. producta which occurred at Eilat, Gulf of Aqaba, Israel, is reported. The symptoms consisted mainly of pain and swelling of the affec...

S. Levy D. Masry B. W. Halstead

1970-01-01

38

Immunohistochemical targeting of sea anemone cytolysins on tentacles, mesenteric filaments and isolated nematocysts of Stichodactyla helianthus.  

PubMed

The toxicity of biomolecules obtained from sea anemones in vitro does not necessarily justify their function as toxins in the physiology of the anemone. That is why anatomical and physiological considerations must be taken into account in order to define their physiological role in the organism. In this work, antibodies generated to Sticholysin II, a cytolysin produced by the Caribbean Sea anemone Stichodactyla helianthus, are used as specific markers to explore the sites of production and storage of the cytolysin in the sea anemone. The immunoperoxidase staining developed gave specific dark-brown staining in tentacles and mesenteric filaments as well as in basitrichous nematocysts isolated from tentacles of S. helianthus. These results support the role of these proteins as toxins in the physiology of the anemone, especially in functions such as in predation, defense and digestion. PMID:16432881

Basulto, Ariel; Pérez, Viviana M; Noa, Yarielys; Varela, Carlos; Otero, Anselmo J; Pico, María C

2006-03-01

39

THE ALLOMETRY OF FEEDING, ENERGETICS, AND BODY SIZE IN THREE SEA ANEMONE SPECIES  

Microsoft Academic Search

Three sea anemone species (Anthopleura elegantissima. A. xanthogrammica, and Metridium senile) were used to examine allometric and energetic properties of body size in passive suspension feeders. Photographs of expanded anemones in the field showedthat projectedfeedingsurfacearea(tentacle crown) asa function of body size increased at, or less than, the rate expected for a geometric solid (0.45â€\\

KENNETH P. SEBENS

1981-01-01

40

Biogeography of Two Species of Symbiodinium (Freudenthal) Inhabiting the Intertidal Sea Anemone Anthopleura elegantissima (Brandt)  

Microsoft Academic Search

We have analyzed the genetic profiles of dinoflagellate populations obtained from the Pacific coast sea anemone Anthopleura elegantissima(Brandt) at collec- tion sites from Washington to California. Genetic dif- ferences within the symbiont populations of California anemones have been uncovered by restriction length polymorphism (RFLP) analysis of the small subunit (SSU) and large subunit (LSU) ribosomal RNA genes, and by denaturing

T. C. LAJEUNESSE; R. K. TRENCH

2000-01-01

41

Uptake and Assimilation of Dissolved Inorganic Nitrogen by a Symbiotic Sea Anemone  

Microsoft Academic Search

The tropical sea anemone, Aiptasia pulchella, harbours symbiotic dinoflagellates (zooxanthellae). Animals in their natural habitat in Hawaii and those maintained in the laboratory in Los Angeles took up ammonium from nutrient enriched seawater. That the uptake experiment was done in the dark did not influence uptake although prolonged (19 h) dark treatment caused the animals to release ammonium. Aposymbiotic anemones

Frances P. Wilkerson; L. Muscatine

1984-01-01

42

Host feeding and nutrient sufficiency for zooxanthellae in the sea anemone Aiptasia pallida  

Microsoft Academic Search

Nutrient sufficiency of zooxanthellae in the sea anemone Aiptasia pallida cultured in low nutrient seawater depends on the availability of particulate food to the host. Zooxanthellae in anemones unfed for 20 to 30 d exhibited the following characteristics of nutrient deficiency: cell division rates decreased; chlorophyll a content gradually decreased from 2 to -1; and C:N ratios increased from 7.5

C. B. Cook; C. F. D'Elia; G. Muller-Parker

1988-01-01

43

ATP enhances repair of hair bundles in sea anemones.  

PubMed

Hair bundle mechanoreceptors of sea anemones are similar to those of the acousticolateralis system of vertebrates (Watson, Mire and Hudson, 1997, Hear. Res. 107, 53-63). Anemone hair bundles are repaired by 'repair proteins' secreted following a complete loss of structural integrity and loss of function caused by 1 h exposure to calcium free seawater. Exogenously supplied repair proteins (RP) restore structural integrity to hair bundles and restore vibration sensitivity in 7-8 min (Watson, Mire and Hudson, 1998, Hear. Res. 115, 119-128). We here report that exogenously supplied ATP enhances the rate by which RP restore vibration sensitivity. A bimodal dose response to ATP indicates maximal enhancement at picomolar and micromolar concentrations of ATP. At these concentrations of ATP, vibration sensitivity is restored in 2 min. These data suggest that at least two ATPases exhibiting different binding affinities for ATP are involved in the repair process. Whereas the higher affinity site is specific for ATP, the lower affinity site does not discriminate between ATP and ADP. Nucleotidase cytochemistry localizes ATPase activity in isolated repair proteins. In the absence of exogenously added RP, sea anemones secrete and consume ATP during the 4 h recovery period after 1 h exposure to calcium free seawater. In the presence of exogenously added RP, ATP is secreted and then consumed within 10 min. Quinacrine cytochemistry localizes possible stores of ATP in the apical cytoplasm of sensory neurons located at the center of the hair bundle. According to our model, ATP is secreted by the sensory neuron after its hair bundle loses structural integrity. Hydrolysis of ATP by repair proteins is essential to the repair process. PMID:10511619

Watson, G M; Venable, S; Hudson, R R; Repass, J J

1999-10-01

44

Purification, sequence, and pharmacological properties of sea anemone toxins from Radianthus paumotensis. A new class of sea anemone toxins acting on the sodium channel.  

PubMed

Four new toxins have been isolated from the sea anemone Radianthus paumotensis: RpI, RpII, RpIII, and RpIV. They are polypeptides comprised of 48 or 49 amino acids; the sequence of RpII has been determined. Toxicities of these toxins in mice and crabs are similar to those of the other known sea anemone toxins, but they fall into a different immunochemically defined class. The sequence of RpII shows close similarities with the N-terminal end (up to residue 20) of the previously sequenced long sea anemone toxins, but most of the remaining part of the molecule is completely different. Like the other sea anemone toxins, Radianthus toxins are active on sodium channels; they slow down the inactivation process. Through their Na+ channel action, Radianthus toxins stimulate Na+ influx into tetrodotoxin-sensitive neuroblastoma cells and tetrodotoxin-resistant rat skeletal myoblasts. The efficiency of the toxins is similar in the two cellular systems. In that respect, Radianthus toxins behave much more like scorpion neurotoxins than sea anemone toxins from Anemonia sulcata or Anthopleura xanthogrammica. In binding experiments to synaptosomal Na+ channels, Radianthus toxins compete with toxin II from the scorpion Androctonus australis but not with toxins II and V from Anemonia sulcata. PMID:2412579

Schweitz, H; Bidard, J N; Frelin, C; Pauron, D; Vijverberg, H P; Mahasneh, D M; Lazdunski, M; Vilbois, F; Tsugita, A

1985-07-01

45

Trans -6-hexadecenoic acid and the corresponding alcohol in lipids in the sea anemone Metridium dianthus  

Microsoft Academic Search

Trans-6-hexadecenoic acid was found in polar lipids, triglycerides, was esters and diacylglyceryl ethers of the sea anemoneMetridium dianthus from Passamaquoddy Bay. The corresponding alcomaquoddy Bay. The corresponding alcohol also apparently occurs in the wax esters\\u000a of this species. The long-chain (C20, C22) monoethylenic alcohols reported for other species of sea anemones from neighboring waters were absent and the major alcohol

S. N. Hooper; R. G. Ackman

1971-01-01

46

Redescription and biological aspects of Hormathia alba (Andres, 1881), a luminescent sea anemone (Anthozoa, Actiniaria)  

NASA Astrophysics Data System (ADS)

The sea anemone Hormathia alba (Andres, 1881) is redescribed and definitely established as distinct from H. coronata. Synonymy, external morphology, anatomy and cnidom are treated in detail. Aspects of its reproduction, ecology, distribution and distinctive characteristics are also reported. The species, largely mistaken throughout literature, is rather common on Mediterranean infralittoral soft bottoms. It has also been found in the SW of Ireland. This is the only known sea anemone with luminescence, a feature that has never been reported before.

Tur, J. M.

1993-06-01

47

Genes encoding cytoplasmic intermediate filament proteins of vertebrates revisited: identification of a cytoplasmic intermediate filament protein in the sea anemone Nematostella.  

PubMed

The cytoskeleton is crucial in determining cell architecture, division, motility, transport processes and in local control of signal transduction. Relatives of actin and tubulin are expressed in all phyla, underlining the fundamental importance of conserved cytoskeletal functions. Intermediate filament proteins have evolved in parallel with tissue diversity in the animal kingdom, likely from the demand to adapt one class of cytoskeletal proteins to cell type-restricted functions. Up to now, the evolutionary origin of cytoplasmic intermediate filament proteins remains unknown. Using a known gene encoding a cytoplasmic intermediate filament protein from the hemichordate Saccoglossus kowalevskii, we have identified the first corresponding gene in the sea anemone Nematostella, tentatively named cytovec. Our data reveal a relationship of cytovec with Hydra vulgaris nematocilins A and B that also lack a CAAX box. In light of additional recent findings, our data show that cytoplasmic intermediate filament genes are present in the common ancestor of Cnidaria and Bilateria. PMID:22944282

Zimek, Alexander; Thiering, Sören; Weber, Klaus; Magin, Thomas M

2012-10-01

48

Factors affecting zooplankton feeding by the sea anemone Aiptasia pallida  

NASA Astrophysics Data System (ADS)

Effects of various treatments on prey capture, prey ingestion and ingestion time of individual Artemia salina nauplii by the sea anemone Aiptasia pallida Verrill were studied in the laboratory. Exposure to crude Artemia homogenate, 5 × 10-4 M reduced glutathione or 5 × 10-4 M proline significantly decreased the number of Artemia that were captured and ingested but had no significant effect on the ingestion time of individual Artemia. Multiple captures increased the total ingestion time but decreased ingestion time per prey item. Results suggest that, under these conditions, the prey capture phase of zooplankton feeding was somewhat distinct from the ingestion phase since chemical stimuli that significantly reduced prey capture had no significant effect on ingestion time.

Clayton, William S.

1986-03-01

49

A Study of the Muscular Anatomy and Swimming Behaviour of the Sea Anemone, Stomphia coccinea  

Microsoft Academic Search

SUMMARY The sea anemone Stomphia coccinea, when touched by certain starfishes, frees itself from the substratum, and by a series of waving motions propels itself through the water. This locomotion has been studied by means of direct observation and by analysis of time-lapse, and normal-speed motion-picture films. Ecological observations and stimulation tests made in the natural environment of the anemone

PAUL N. SUND

50

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

Microsoft Academic Search

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

Cadet Hand; Kevin R. Uhlinger

51

Influence of copper pre-exposure on biochemical responses of the sea anemone Bunodosoma cangicum to changes in oxygen availability.  

PubMed

The influence of copper on the ability of the intertidal sea anemone Bunodosoma cangicum to cope with reactive oxygen species generation associated with changes in oxygen availability was evaluated. Sea anemones were kept under control condition or pre-exposed (96 h) to dissolved copper (6.1 ?g ± 2.7 ?g/L) and then subjected to a 6-h period of hypoxia (0.5mg O?/L) followed by a 6-h period of re-oxygenation (7.5mg O?/L). Antioxidant capacity against peroxyl radicals (ACAP), superoxide dismutase (SOD) activity, reduced glutathione (GSH) concentration, lipid peroxidation (LPO) level, and ATP concentration were evaluated. Control sea anemones showed variations in SOD and LPO while copper pre-exposed sea anemones displayed changes in ACAP, GSH, LPO and ATP. However, no clear pattern of change over time was observed. ACAP was lower in copper pre-exposed sea anemones than in the control ones during hypoxia and recovery. SOD activity was increased during hypoxia and reduced shortly after recovery in control sea anemones. GSH concentration was higher in copper pre-exposed sea anemones than in the control ones in all experimental conditions. The LPO level increased shortly after recovery in both groups of sea anemones, being higher in control sea anemones than in copper pre-exposed ones. ATP concentration showed transient changes in copper pre-exposed sea anemones, being lower in these sea anemones than in control ones during recovery. These findings suggest that B. cangicum possess mechanisms to prevent oxidative stress generated by changes in oxygen availability associated with the tidal cycle, which can be disturbed by pre-exposure to copper. PMID:24667761

Abujamara, Laís Donini; Prazeres, Martina de Freitas; Borges, Vinícius Dias; Bianchini, Adalto

2014-05-01

52

Population characteristics of the intertidal green sea anemone, Anthopleura xanthogrammica, on the Oregon coast  

NASA Astrophysics Data System (ADS)

Field population censuses using a photographic quadrat method were used to describe the density and size structure of intertidal populations of the green sea anemone, Anthopleura xanthogrammica, on different types of rocky intertidal habitats on the Oregon coast. Anemone populations in marked plots were monitored for individual motility, growth, mortality and recruitment. Experiments were performed to evaluate anemone population responses to simulated harvesting. Rocky intertidal locations with dense populations of the green anemone are not abundant along the Oregon coast. No detectable fluctuations in anemone population density or size-frequency distribution were found during the 2-year study. Adult anemones showed little movement in either disturbed or undisturbed populations. No natural mortality or recruitment was found in study plots at any Oregon coastal location between July 1977 and May 1979. Removal of adult anemones from rock surfaces did not promote recruitment from the plankton onto the newly available surface, nor did individuals adjacent to depopulated plots rapidly immigrate into the cleared areas. Individual growth is inferred to be very slow in intertidal populations. Field studies indicate that A. xanthogrammica is a long-lived, slow growing species with limited, low or erratic recruitment and highly stable intertidal adult populations. This study indicates that harvest of A. xanthogrammica will probably not be possible on a continuing basis.

Batchelder, H. P.; Gonor, J. J.

1981-09-01

53

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

PubMed

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

Vieira, Leandro M; Stampar, Sergio N

2014-01-01

54

The role of symbiotic dinoflagellates in the temperature-induced bleaching response of the subtropical sea anemone Aiptasia pallida  

Microsoft Academic Search

Coral bleaching involves the loss of symbiotic dinoflagellates (zooxanthellae) from reef corals and other cnidarians and may be a stress response of the host, algae or both. To determine the role of zooxanthellae in the bleaching process, aposymbiotic sea anemones from Bermuda (Aiptasia pallida) were infected with symbionts from other sea anemones (Aiptasia pallida from Florida, Bartholomea annulata and Condylactis

Santiago F Perez; Clayton B Cook; W. Randy Brooks

2001-01-01

55

Proteomics of the neurotoxic fraction from the sea anemone Bunodosoma cangicum venom: Novel peptides belonging to new classes of toxins  

Microsoft Academic Search

In contrast to the many studies on the venoms of scorpions, spiders, snakes and cone snails, up to now there has been no report of the proteomic analysis of sea anemones venoms. In this work we report for the first time the peptide mass fingerprint and some novel peptides in the neurotoxic fraction (Fr III) of the sea anemone Bunodosoma

André Junqueira Zaharenko; Wilson Alves Ferreira; Joacir Stolarz Oliveira; Michael Richardson; Daniel Carvalho Pimenta; Katsuhiro Konno; Fernanda C. V. Portaro; José Carlos de Freitas

2008-01-01

56

Binding of a radiolabeled sea anemone cytolysin to erythrocyte membranes.  

PubMed

Stichodactyla helianthus cytolysin III, a 17 kDa basic polypeptide isolated from a Caribbean sea anemone, is one of the most potent hemolysins yet found in a living organism. This toxin has been reported to form new ion channels in artificial lipid bilayer membranes. The ability of this toxin to attack cell membranes is greatly enhanced by the presence of sphingomyelin. In order to investigate the mechanism by which the cytolysin causes cell lysis, we have prepared a highly active [3H]cytolysin derivative by reductive methylation with sodium cyanoborohydride and [3H]formaldehyde. A dimethylated toxin derivative was used to investigate the basis for the differential lytic activity of this polypeptide upon erythrocytes from six mammalian species. Using both direct [3H]toxin binding and indirect (Thron method) binding techniques, we found that the interspecies differences are due to variable membrane susceptibilities toward the bound toxin, rather than to differences in membrane affinity for the toxin. Similarly, we showed the enhanced lytic activity of the toxin for rat erythrocytes at elevated pH to be caused by enhanced activity of the bound toxin. PMID:2574996

Doyle, J W; Kem, W R

1989-12-28

57

Effects of feeding regime on growth rate in the Mediterranean Sea anemone Actinia equina (Linnaeus)  

Microsoft Academic Search

Polyps of Actinia equina are the most common sea anemones in the rocky intertidal zone of the Mediterranean coast of Israel, where they occur in one of the southernmost populations of this species in the northern hemisphere. We examined effects of feeding rate on polyp growth at ambient sea temperature for this population. Under laboratory conditions, polyps were left unfed,

O. Chomsky; Y. Kamenir; M. Hyams; Z. Dubinsky; N. E. Chadwick-Furman

2004-01-01

58

Biogeography of Antarctic sea anemones (Anthozoa, Actiniaria): What do they tell us about the origin of the Antarctic benthic fauna?  

NASA Astrophysics Data System (ADS)

The present study of the biogeography of the Antarctic sea anemone fauna is based on new records and redescriptions of material collected from the Weddell Sea and Peninsula Antarctica, and on an update of the bibliographic data of the Antarctic and sub-Antarctic regions. The faunal compositions at different levels, the geographic and bathymetric distributions of the sea anemone fauna, and the affinities within the continent and with the sub-Antarctic fauna have been studied. Furthermore, the relationships of the sea anemone fauna, of the Southern Ocean, the Mediterranean Sea and Hawaii have been analysed. In this context, the origin of the Antarctic benthic fauna is discussed.

Rodríguez, E.; López-González, P. J.; Gili, J. M.

2007-08-01

59

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

PubMed Central

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.

Bosmans, Frank; Tytgat, Jan

2007-01-01

60

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

PubMed

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

Tang, Pei-Ciao; Watson, Glen M

2014-01-01

61

Catch-tentacles in sea anemones: occurrence in Haliplanella luciae (Verrill) and a review of current knowledge  

Microsoft Academic Search

The occurrence of catch-tentacles or Fangtentakeln in the sea anemone Haliplanella luciae is reported for the first time, and some aspects of their anatomy and behaviour are noted. Provision is made for this discovery in the diagnoses of the family Haliplanellidae and the genus Haliplanella. The species of acontiarian anemones at present known to possess catch-tentacles are listed. The cnidom

R. B. Williams

1975-01-01

62

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

Microsoft Academic Search

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

W. K. Fitt; R. L. Pardy

1981-01-01

63

A polypeptide toxin in the sea anemone Actinia equina homologous with other sea anemone sodium channel toxins: Isolation and amino acid sequence  

Microsoft Academic Search

The sea anemone (Actinia equina) was newly established to contain a polypeptide toxin (named Ae I) having lethal activity to crabs, besides the well-known cytolytic toxins (equinatoxins) of proteinic nature. Ae I, with a minimum lethal dose against crabs of 25 ?g\\/kg, was easily isolated by gel filtration on Sephadex G-50 and reverse-phase HPLC on Nucleosil 300-7C18. Its amino acid

Xin-yu Lin; Masami Ishida; Yuji Nagashima; Shiomi Kazuo

1996-01-01

64

Feeding behavior and acquisition of zooxanthellae by planula larvae of the sea anemone Anthopleura elegantissima  

Microsoft Academic Search

Symbiotic associations between cnidarians and photosynthetic dinoflagellates (i.e., zooxanthellae) are common in the marine environment. Many symbiotic cnidarians produce offspring that are initially nonsymbiotic. These new hosts must acquire symbiotic algae from environmental sources. We examined zooxanthella acquisition by laboratory-reared planula larvae of the temperate sea anemone Anthopleura elegantissima. Larvae ingested zooxanthellae while they were feeding. However, the signal that

J. A. Schwarz; V. M. Weis; D. C. Potts

2002-01-01

65

Copper accumulation and oxidative stress in the sea anemone, Aiptasia pallida, after waterborne copper exposure  

Microsoft Academic Search

Copper is a common marine pollutant yet its effects on symbiotic cnidarians are largely understudied. To further understand the impact of elevated copper concentrations on marine symbiotic organisms, toxicity tests were conducted using the model sea anemone, Aiptasia pallida, with and without its zooxanthellae symbiont. Symbiotic and aposymbiotic A. pallida were exposed to sublethal copper concentrations (0, 5, 15, and

W. P. L. Main; C. Ross; G. K. Bielmyer

2010-01-01

66

Effects of temperature on growth rate and body size in the Mediterranean Sea anemone Actinia equina  

Microsoft Academic Search

Actinia equina is the most common sea anemone in the rocky intertidal zone of the Mediterranean coast of Israel, yet little is known about its biology in this habitat. We examined variation in polyp growth at several temperatures within the local range. Under laboratory conditions, only polyps at low temperatures (15 and 20 °C) grew, whereas those at higher temperatures

O. Chomsky; Y. Kamenir; M. Hyams; Z. Dubinsky; N. E. Chadwick-Furman

2004-01-01

67

Cardiovascular effects of equinatoxin III from the sea anemone Actinia equina (L.)  

Microsoft Academic Search

Equinatoxin III is the most hemolytic, and the least lethal of the three basic proteins isolated from the sea anemone Actinia equina (L.). Its LD50 in mice is 83?g\\/kg. Preliminary results on Wistar rats have suggested cardiorespiratory arrest as a putative cause of death, but the mechanism of its action has not yet been studied. So far only equinatoxin II

Dušan Šuput; Robert Frangež; Matjaž Bunc

2001-01-01

68

The sea anemone Actinia equina tolerates allogeneic juveniles but alters their phenotype  

Microsoft Academic Search

Actinia equina is a variably coloured sea anemone that broods juveniles within its body cavity. Male, female and non-sexual individuals can produce juveniles, even after periods of isolation, and it has been suggested that this species is capable of reproducing by asexual or parthenogenetic means. Further evidence in favour of this hypothesis has been derived from similarities in coloration and

Roger Lubbock; Catherine Allbut

1981-01-01

69

Cloning and sequencing of cDNA encoding glutamine synthetase from the sea anemone Aiptasia pallida  

Microsoft Academic Search

Glutamine synthetase (GS) catalyzes the addition of ammonium to glutamic acid to form glutamine and plays a crucial role in the nitrogen assimilation of the sea anemone Aiptasiapallida and its endosymbiotic algae. We describe the cDNA cloning and sequence analysis of GS mRNA from A. pallida based on polymerase chain reaction (PCR) technology that employed a combination of degenerate and

Oney P. Smith; Anthony D. Marinov; Karen M. Chan; M. Drew Ferrier

2004-01-01

70

Accumulation of Glutamate in Sea Anemones Exposed to Heavy Metals and Organic Amines.  

National Technical Information Service (NTIS)

In the present study, the Gulf Coast sea anemone, Bunodosoma cavernata, was used as the test animal and free amino acid levels of whole animals were measured following stressed conditions. While free glycine in B. cavernata generally shows a reduction in ...

M. R. Kasschau M. M. Skaggs E. C. M. Chen

1980-01-01

71

MECHANICAL DIVERSITY OF CONNECTIVE TISSUE OF THE BODY WALL OF SEA ANEMONES  

Microsoft Academic Search

SUMMARY Techniques for analysing polymer mechanics were used to describe quantitatively the time-dependent mechanical properties of the body-wall connective tissue (mesogloea) and to indicate macromolecular mechanisms responsible for the mechanical behaviour of two species of sea anemones, Metridium senile and Anthopleura xanthogrammica. 1. The mesogloea of M. senile is more extensible and less resilient than that of A. xanthogrammica when

M. A. R. KOEHL

1977-01-01

72

OBSERVATIONS ON THE SYMBIOSIS OF THE SEA ANEMONE STOICHACTIS AND THE POMACENTRID FISH, AMPHIPRION PERCULA  

Microsoft Academic Search

The partnership between certain tropical damselfishes and sea anemones has excited the interest of students of natural history for almost a century. The most significant investigations of the symbiosis have been those of Sluiter (1888), Ver wey (1930) and Gohar (1948), who have given us some knowledge of the ecology and behavioral characteristics of the animals. In 1947 Gudger reviewed

DEMOREST DAVENPORT; KENNETH S. NORRIS

73

Characterization of a potassium channel toxin from the Caribbean sea anemone Stichodactyla helianthus  

Microsoft Academic Search

A peptide toxin, ShK, that blocks voltage-dependent potassium channels was isolated from the whole body extract of the Caribbean sea anemone Stichodactyla helianthus. It competes with dendrotoxin I and ?-dendrotoxin for binding to synaptosomal membranes of rat brain, facilitates acetylcholine release at an avian neuromuscular junction and suppresses K+ currents in rat dorsal root ganglion neurones in culture. Its amino

Olga Castañeda; Vivian Sotolongo; Ana Maria Amor; Reto Stöcklin; Amanda J. Anderson; Alan L. Harvey; Åke Engström; Christer Wernstedt; Evert Karlsson

1995-01-01

74

SOCIAL ORGANIZATION WITHIN CLONES OF THE SEA ANEMONE ANTHOPLEURA ELEGANTISSIMA  

Microsoft Academic Search

The aggregating form of the anemone Anthopleura elegantissinla often lives at tached to large boulders and rocky outcroppings in closely packed groups. These are composed of genetically identical individuals, the products of asexual reproduc tion ( Francis, 1973a) . Contact between the tentacles of genetically different (non clonemate) members of the species elicits aggression in one or both animals, while

LISBETH FRANCIS

1976-01-01

75

Identity between cytolysins purified from two morphos of the Caribbean sea anemone Stichodactyla helianthus.  

PubMed

Stichodactyla helianthus is a sea anemone relatively abundant along Cuban coasts appearing in two morphos with different colors in their tentacles: green or brownish, probably due to their association with algal symbionts. Traditionally, the brownish morpho has been used as a source of sticholysins I and II, the most characterized cytolysins from this anemone, but the green morpho is the most abundant along the western coasts of Havana. The present work is aimed to establish if the cytolysins purified from the green morpho (StIg and StIIg) are similar to those purified from brownish anemones (StI and StII). Following the same chromatographic procedure used to purify the toxins from morphos, the electrophoretic mobilities, amino acid compositions, amino terminal sequences and molecular masses were practically identical between analogal cytolysins. In conclusion, homologous sticholysins purified from the green and brownish variants of Stichodactyla helianthus are the same molecular entities. PMID:12165325

Martínez, Diana; Morera, Vivian; Alvarez, Carlos; Tejuca, Mayra; Pazos, Fabiola; García, Yairet; Raida, Manfred; Padrón, Gabriel; Eliana Lanio, María

2002-08-01

76

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

PubMed

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

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

2013-05-01

77

Short Toxin-like Proteins Abound in Cnidaria Genomes  

PubMed Central

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.

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

2012-01-01

78

Short toxin-like proteins abound in Cnidaria genomes.  

PubMed

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

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

2012-11-01

79

Characterization of a potassium channel toxin from the Caribbean Sea anemone Stichodactyla helianthus.  

PubMed

A peptide toxin, ShK, that blocks voltage-dependent potassium channels was isolated from the whole body extract of the Caribbean sea anemone Stichodactyla helianthus. It competes with dendrotoxin I and alpha-dendrotoxin for binding to synaptosomal membranes of rat brain, facilities acetylcholine release at an avian neuromuscular junction and suppresses K+ currents in rat dorsal root ganglion neurones in culture. Its amino acid sequence is R1SCIDTIPKS10RCTAFQCKHS20MKYRLSFCRK30TCGTC35. There is no homology with other K+ channel-blocking peptides, except for BgK from the sea anemone Bunodosoma granulifera. ShK and BgK appear to be in a different structural class from other toxins affecting K+ channels. PMID:7660365

Castañeda, O; Sotolongo, V; Amor, A M; Stöcklin, R; Anderson, A J; Harvey, A L; Engström, A; Wernstedt, C; Karlsson, E

1995-05-01

80

[Polypeptide toxin from sea anemone inhibiting proton-sensitive channel ASIC3].  

PubMed

Polypeptide toxin pi-AnmTX Hcr 1b-1 with a molecular weight 4537 Da was isolated from the whole body extract of sea anemone by a multistage liquid chromatography. The BLAST search algorithm revealed homology of the novel toxin amino acid sequence to the group of the known sea anemone toxins including BDS and APETx with similarity less then 50%. The toxin pi-AnmTX Hcr 1b-1 inhibited the amplitude of the fast component of integral ASIC3 current in electrophysiological studies on receptors expressed in Xenopus laevis oocytes. The calculated IC50 value was 5.5 +/- 1.0 microM. Among the known polypeptide toxins interacted with ASICs channels, the micro-AnmTX Hcr 1b-1 toxin is the least potent inhibitor that in our opinion correlates with a small amount of charged amino acid residues in its structure. PMID:23547468

Kozlov, S A; Osmakov, D I; Andreev, Ia A; Koshelev, S G; Gladkikh, I N; Monastyrnaia, M M; Kozlovskaia, E P; Grishin, E V

2012-01-01

81

Primary structure of a potassium channel toxin from the sea anemone Actinia equina  

Microsoft Academic Search

A potassium channel toxin (AeK) was isolated from the sea anemone Actinia equina by gel filtration on Sephadex G-50 and reverse-phase HPLC on TSKgel ODS-120T. AeK and ?-dendrotoxin inhibited the binding of 125I-?-dendrotoxin to rat synaptosomal membranes with IC50 of 22 and 0.34 nM, respectively, indicating that AeK is about sixty-five times less toxic than ?-dendrotoxin. The complete amino acid

Sonomi Minagawa; Masami Ishida; Yuji Nagashima; Kazuo Shiomi

1998-01-01

82

Novel peptide toxins from acrorhagi, aggressive organs of the sea anemone Actinia equina  

Microsoft Academic Search

Two peptide toxins, acrorhagin I (50 residues) and II (44 residues), were isolated from special aggressive organs (acrorhagi) of the sea anemone Actinia equina by gel filtration on Sephadex G-50 and reverse-phase HPLC on TSKgel ODS-120T. The LD50 against crabs of acrorhagin I and II were estimated to be 520 and 80?g\\/kg, respectively. 3?- and 5?-RACE established the amino acid

Tomohiro Honma; Sonomi Minagawa; Hiroshi Nagai; Masami Ishida; Yuji Nagashima; Kazuo Shiomi

2005-01-01

83

Equinatoxins, pore-forming proteins from the sea anemone Actinia equina, belong to a multigene family  

Microsoft Academic Search

The multigene family of equinatoxins, pore-forming proteins from sea anemone Actinia equina, has been studied at the protein and gene levels. We report the cDNA sequence of a new, sphingomyelin inhibited equinatoxin, EqtIV. The N-terminal sequences of natural Eqt I and III were also determined, confirming two isoforms of EqtI, differing at position 13. The number of Eqt genes determined

Gregor Anderluh; Igor Križaj; Borut Štrukelj; Franc Gubenšek; Peter Ma?ek; Jože Punger?ar

1999-01-01

84

Cloning and sequencing of cDNA encoding glutamine synthetase from the sea anemone Aiptasia pallida  

Microsoft Academic Search

Glutamine synthetase (GS) catalyzes the addition of ammonium to glutamic acid to form glutamine and plays a crucial role in\\u000a the nitrogen assimilation of the sea anemone Aiptasia pallida and its endosymbiotic algae. We describe the cDNA cloning and sequence analysis of GS mRNA from A. pallida based on polymerase chain reaction (PCR) technology that employed a combination of degenerate

Oney P. Smith; Anthony D. Marinov; Karen M. Chan; M. Drew Ferrier

85

THE CYTOTOXIC AND CYTOLYTIC ACTIVITY OF EQUINATOXIN II FROM THE SEA ANEMONE Actinia epina  

Microsoft Academic Search

The cytotoxic and cytolytic effects of equinatoxin II (EqT II from the sea anemone Actinia equina L. were studied on exponenti ad y growing and synchronized V-79-379 A cell line in culture. The cell viability test and the determination of the cytolytic effect by cell counting confirmed both cytotoxic and cytolytic activity of EqT II. Additionally, cytocidal and cytostatic effects

PETER MAcEK; BOJAN SEDMAK

86

Photosynthesis-irradiance responses and photosynthetic periodicity in the sea anemone Aiptasia pulchella and its zooxanthellae  

Microsoft Academic Search

Sea anemones (Aiptasia pulchella) containing zooxanthellae (Symbiodinium microadriaticum) were maintained in a long-term laboratory culture on a 12 h light (100 µE m-2 s-1):12 h dark cycle. Photosynthetic oxygen production was measured for the symbiotic association and for freshlyisolated zooxanthellae. Light utilization efficiencies (a) were similar for both sets of zooxanthellae, suggesting negligible shading of zooxanthellae by animal tissue in

G. Muller-Parker

1984-01-01

87

LOW TEMPERATURE EVOKES RAPID EXOCYTOSIS OF SYMBIOTIC ALGAE BY A SEA ANEMONE  

Microsoft Academic Search

Darknessevokes expulsion ofzooxanthellae from the sea anemone Aiptasia pu! chella, but brief exposure to low temperature(4°C, 4 h) increasesthe expulsion rate four-fold. Ninety-eight percent of the zooxanthellae are expelled within four days. Low temperature incubation had no detectable effect on host animal survival or be havior, but the effect on zooxanthellae was profound. Low temperaturereduced the rateofphotosynthesis, increasedthe rateofrelease offixed

R. GRANT STEEN; L MUSCATINE

88

A novel sea anemone peptide that inhibits acid-sensing ion channels.  

PubMed

Sea anemones produce ion channels peptide toxins of pharmacological and biomedical interest. However, peptides acting on ligand-gated ion channels, including acid-sensing ion channel (ASIC) toxins, remain poorly explored. PhcrTx1 is the first compound characterized from the sea anemone Phymanthus crucifer, and it constitutes a novel ASIC inhibitor. This peptide was purified by gel filtration, ion-exchange and reversed-phase chromatography followed by biological evaluation on ion channels of isolated rat dorsal root ganglia (DRG) neurons using patch clamp techniques. PhcrTx1 partially inhibited ASIC currents (IC50?100 nM), and also voltage-gated K(+) currents but the effects on the peak and on the steady state currents were lower than 20% in DRG neurons, at concentrations in the micromolar range. No significant effect was observed on Na(+) voltage-gated currents in DRG neurons. The N-terminal sequencing yielded 32 amino acid residues, with a molecular mass of 3477 Da by mass spectrometry. No sequence identity to other sea anemone peptides was found. Interestingly, the bioinformatic analysis of Cys-pattern and secondary structure arrangement suggested that this peptide presents an Inhibitor Cystine Knot (ICK) scaffold, which has been found in other venomous organisms such as spider, scorpions and cone snails. Our results show that PhcrTx1 represents the first member of a new structural group of sea anemones toxins acting on ASIC and, with much lower potency, on Kv channels. Moreover, this is the first report of an ICK peptide in cnidarians, suggesting that the occurrence of this motif in venomous animals is more ancient than expected. PMID:23764262

Rodríguez, Armando Alexei; Salceda, Emilio; Garateix, Anoland Georgina; Zaharenko, André Junqueira; Peigneur, Steve; López, Omar; Pons, Tirso; Richardson, Michael; Díaz, Maylín; Hernández, Yasnay; Ständker, Ludger; Tytgat, Jan; Soto, Enrique

2014-03-01

89

Secondary Structure of Sea Anemone Cytolysins in Soluble and Membrane Bound Form by Infrared Spectroscopy  

Microsoft Academic Search

Attenuated total reflection (ATR) Fourier transform infrared spectroscopy (FTIR) was used to investigate the secondary structure of two pore-forming cytolysins from the sea anemoneStichodactyla helianthusand their interaction with lipid membranes. Frequency component analysis of the amide I' band indicated that these peptides are composed predominantly of beta structure, comprising 44–50% ?-sheet, 18–20% ?-turn, 12–15% ?-helix, and 19–22% random coil. Upon

Gianfranco Menestrina; Veronique Cabiaux; Mayra Tejuca

1999-01-01

90

Spontaneous contractions and nerve net activity in the sea anemone calliactis parasitica  

Microsoft Academic Search

Suction electrodes attached to tentacles of the sea anemone Calliactis parasitica record regular bursts of activity associated with the through?conducting nerve net. Most bursts consist of 10–15 pulses at a frequency of 1 every 4 sec to 1 every 10 sec. The interval between bursts is usually 10–20 min. Regularity in pulse number and frequency in successive bursts suggests that

I. D. McFarlane

1973-01-01

91

Short-term stability of genetic structure in populations of the sea anemone Metridium senile  

Microsoft Academic Search

Populations of the sea anemone Metridium senile (L.) were sampled from several locations in eastern North America in two series, one collected from 1977–1979 and the other from 1981–1985. Fourteen populations were sampled twice at one- to six-year intervals. Samples were analyzed for temporal differences in genetic composition at both the single locus and multiple locus levels. Overall patterns of

R. J. Hoffmann; Mount Desert; Salsbury Cove

1987-01-01

92

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

NASA Astrophysics Data System (ADS)

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.

Rodríguez, Estefanía

2012-06-01

93

The influence of irradiance on the severity of thermal bleaching in sea anemones that host anemonefish  

NASA Astrophysics Data System (ADS)

Entacmaea quadricolor is a geographically widespread species of sea anemone that forms a three-way symbiosis with anemonefish and Symbiodinium. This species dominates the reef substrata at North Solitary Island, Australia, which is located in a region identified as a climate change hot spot. Their geographic location places these anemones under significant threat from rising ocean temperatures, although their upper thermal limit and risk of bleaching are unknown. To address this knowledge gap, anemones were exposed to one of four temperatures (23, 25, 27, or 29°C) and one of two irradiance treatments (high or low light) over 6 days. At moderate temperatures (27°C, 1°C above summer average), anemone bleaching was characterised by symbiont expulsion, while extreme temperatures (29°C) resulted in an additional loss of photosynthetic pigments from within symbionts, and in some cases, host mortality. Irradiance influenced the susceptibility to thermal stress with high light promoting the bleaching response, along with significant reductions in the effective quantum yield of anemone symbionts. The long-term loss of photosystem II photochemical efficiency within in hospite symbionts was observed during exposure to temperatures exceeding the summer average, indicating photosynthetic damage. The resident Symbiodinium, identified as clade C using 28S rRNA gene sequences, therefore represents the partner within the symbiosis that is likely to be most vulnerable to rising seawater temperatures. Results suggest that E. quadricolor is living within approximately 1°C of the upper thermal maximum at the Solitary Islands, and given the predictions for rising seawater temperature on Australia's east coast, the thermal threshold at which bleaching will occur is expected to be reached and exceeded more frequently in the future.

Hill, R.; Scott, A.

2012-03-01

94

Tiny Sea Anemone from the Lower Cambrian of China  

PubMed Central

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.

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

2010-01-01

95

Relationships between host and symbiont cell cycles in sea anemones and their symbiotic dinoflagellates.  

PubMed

The processes by which cnidarians and their algal endosymbionts achieve balanced growth and biomass could include coordination of host and symbiont cell cycles. We evaluated this theory with natural populations of sea anemones hosting symbiotic dinoflagellates, focusing on the temperate sea anemone Anthopleura elegantissima symbiotic with Symbiodinium muscatinei in Washington State, USA, and the tropical anemone Stichodactyla helianthus associating with unknown Symbiodinium spp. in Belize. By extruding symbiont-containing gastrodermal cells from the relatively large tentacles of these species and using nuclear staining and flow cytometry, we selectively analyzed cell cycle distributions of the symbionts and the host gastrodermal cells that house them. We found no indications of diel synchrony in host and symbiont G2/M phases, and we observed evidence of diel periodicity only in Symbiodinium spp. associated with S. helianthus but not in the anemone itself. Seasonally, S. muscatinei showed considerable G2/M phase variability among samples collected quarterly over an annual period, while the G2/M phase of its host varied much less. Within samples taken at different times of the year, correlations between host and symbiont G2/M phases ranged from very weakly to very strongly positive, with significant correlations in only half of the samples (two of four A. elegantissima samples and one of two S. helianthus samples). Overall, the G2/M phase relationships across species and sampling periods were positive. Thus, while we found no evidence of close cell cycle coupling, our results suggest a loose, positive relationship between cell cycle processes of the symbiotic partners. PMID:24243963

Dimond, James L; Pineda, Rea R; Ramos-Ascherl, Zullaylee; Bingham, Brian L

2013-10-01

96

Isolation and biological characterization of neurotoxic compounds from the sea anemone Lebrunia danae (Duchassaing and Michelotti, 1860)  

Microsoft Academic Search

This paper describes two neurotoxic proteins obtained from the Caribbean sea anemone Lebrunia danae. To assess the neurotoxic activity of the venom of L. danae, several bioassays were carried out, and to evaluate the effect of the toxin, Median Lethal Doses (LD50) were determined in vivo using sea crabs (Ocypode quadrata) and Artemia salina nauplii with the crude extract of

J. Sánchez-Rodríguez; Karina Cruz-Vazquez

2006-01-01

97

Chemical modification of equinatoxin II, a lethal and cytolytic toxin from the sea anemone Actinia equina L  

Microsoft Academic Search

T.TURK, P.MALEx and F.GuBEN~EK .Chemical modification of equinatoxin II,a lethaland cytolytictoxin from the sea anemone ActiniaequinaL .Toxicon 27,37384, 1989 .-The role of arginineand tyrosinein cytolyticpropertiesof equinatoxin II,isolatedfrom the sea anemone ActiniaequinaL.,was studied by means of chemical modifications.The toxin was modified with 2,3 butane- dione and tetranitromethane, respectively. The extent of modification and physico-chemical propertiesof the modified proteinswere checked with amino

TOM TURK; P MACEK; F GUBENSEK

1989-01-01

98

Concerted evolution of sea anemone neurotoxin genes is revealed through analysis of the Nematostella vectensis genome.  

PubMed

Gene families, which encode toxins, are found in many poisonous animals, yet there is limited understanding of their evolution at the nucleotide level. The release of the genome draft sequence for the sea anemone Nematostella vectensis enabled a comprehensive study of a gene family whose neurotoxin products affect voltage-gated sodium channels. All gene family members are clustered in a highly repetitive approximately 30-kb genomic region and encode a single toxin, Nv1. These genes exhibit extreme conservation at the nucleotide level which cannot be explained by purifying selection. This conservation greatly differs from the toxin gene families of other animals (e.g., snakes, scorpions, and cone snails), whose evolution was driven by diversifying selection, thereby generating a high degree of genetic diversity. The low nucleotide diversity at the Nv1 genes is reminiscent of that reported for DNA encoding ribosomal RNA (rDNA) and 2 hsp70 genes from Drosophila, which have evolved via concerted evolution. This evolutionary pattern was experimentally demonstrated in yeast rDNA and was shown to involve unequal crossing-over. Through sequence analysis of toxin genes from multiple N. vectensis populations and 2 other anemone species, Anemonia viridis and Actinia equina, we observed that the toxin genes for each sea anemone species are more similar to one another than to those of other species, suggesting they evolved by manner of concerted evolution. Furthermore, in 2 of the species (A. viridis and A. equina) we found genes that evolved under diversifying selection, suggesting that concerted evolution and accelerated evolution may occur simultaneously. PMID:18222944

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

2008-04-01

99

Accumulation of glutamate in sea anemones exposed to heavy metals and organic amines  

SciTech Connect

Stress has been reported to accelerate protein catabolism in man and animals and as a result one can expect to observe changes in certain amino acids pools of these organisms. In the present study, the Gulf Coast sea anemone, Bunodosoma cavernata, was used as the test animal and free amino acid levels of whole animals were measured following stressed conditions. Sea anemones were chosen as the test animals since they are sessile and, due to the nature of their morphology, they have few mechanisms by which they can escape environmental stress. The animals were exposed to sublethal concentrations of mercuric chloride and cadmium chloride and the organic amines, aniline, diethanol amine (DEA), and ethylene diamine (EDA). Chloride salts of mercury and cadmium were chosen rather than other anions since chloride is the most abundant anion in seawater. These two particular metals were chosen as challenge compounds due to their high toxicity in aquatic systems. The three organic amines were chosen for their relatively high water solubility and low vapor pressure in an aqueous solution, thus insuring that the toxic compound is retained in the test solution. Since organic amines are used extensively in the Gulf Coast industrial complex, there is a high probability of these compounds contaminating the marine environment. Results indicate that the reaction of B. cavernata to stress from organic amines is similar to the response to heavy metals, only more extensive.

Kasschau, M.R.; Skaggs, M.M.; Chen, E.C.M.

1980-12-01

100

Bacterial aggregates in the tentacles of the sea anemone Metridium senile  

NASA Astrophysics Data System (ADS)

This paper provides first information on organ-like bacterial aggregates in the tentacles of the sea anemone Metridium senile. The specimens were collected from waters near Helgoland (German Bight, North Sea) and the Orkney Islands. Tentacles were prepared for morphological inspection by light and scanning electron microscopy as well as for the phylogenetic analysis of endocytic bacteria. Bacterial aggregates are located in caverns of the tentacles’ epidermis. The aggregates are enwrapped in thin envelopes, which contain coccoid and/or rod-shaped tightly packed bacteria of different division states. Most of the bacterial cells are connected by fine filamentous structures. The phylogenetic determination is based on the sequence data of the 16S rDNA derived from tentacle material. Sequence analysis revealed three different subgroups of intratentacular proteobacteria. The dominant band, detected in all of the samples tested, showed a close relationship (98%) to a gram-negative Endozoicimonas elysicola. Two bands, only detected in tentacles of M. senile from Helgoland were assigned to Pseudomonas saccherophilia (99%), a knallgas bacterium, and to Ralstonia pickettii (100%). The bacteria represent a specific bacterial community. Their DGGE profiles do not correspond to the profiles of the planktonic bacteria generated from seawater close to the habitats of the anemones. The allocation of DNA sequences to the different morphotypes, their isolation, culturing and the elucidation of the physiological functions of intratentacular bacteria are in progress.

Schuett, Christian; Doepke, Hilke; Grathoff, Annette; Gedde, Michael

2007-09-01

101

Effects of sea anemone ( heteractis magnifica and actinia equina) cytolysins on synaptosomal uptake of gaba and choline  

Microsoft Academic Search

Magnificalysin I and II (HMg I and II) and equinatoxin II (EqTx II) are cytolytic toxins extracted from sea anemones Heteractis magnifica and Actinia equina, respectively. They induced haemolysis in rat red blood cells and inhibited gamma amino butyric acid (GABA) and choline uptake into rat brain synaptosomes. These effects were concentration dependent. The inhibition of GABA and choline uptake

H. E Khoo; J. P. C Lim; C. H Tan

1995-01-01

102

Effects of Lipid Composition on Membrane Permeabilization by Sticholysin I and II, Two Cytolysins of the Sea Anemone Stichodactyla helianthus  

Microsoft Academic Search

Sticholysin I and II (St I and St II), two basic cytolysins purified from the Caribbean sea anemone Stichodactyla helianthus, efficiently permeabilize lipid vesicles by forming pores in their membranes. A general characteristic of these toxins is their preference for membranes containing sphingomyelin (SM). As a consequence, vesicles formed by equimolar mixtures of SM with phosphatidylcholine (PC) are very good

Carlos Alvarez Valcarcel; Mauro Dalla Serra; Cristina Potrich; Ivonne Bernhart; Mayra Tejuca; Diana Martinez; Fabiola Pazos; Maria E. Lanio; Gianfranco Menestrina

2001-01-01

103

Programmed cell death and cell necrosis activity during hyperthermic stress-induced bleaching of the symbiotic sea anemone Aiptasia sp  

Microsoft Academic Search

Different cell death pathways were investigated during bleaching in the sea anemone Aiptasia sp. in response to hyperthermic treatment. Using a suite of techniques, (haematoxylin and eosin staining of paraffin wax-embedded tissue sections, in-situ end labelling (ISEL) of fragmented DNA, agarose gel electrophoresis electron microscopy) both necrotic and programmed cell death (PCD) activity were indicated. After a treatment period of

Simon R Dunn; John C Bythell; Martin D. A Le Tissier; William J Burnett; Jeremy C Thomason

2002-01-01

104

A natural point mutation changes both target selectivity and mechanism of action of sea anemone toxins.  

PubMed

APETx3, a novel peptide isolated from the sea anemone Anthopleura elegantissima, is a naturally occurring mutant from APETx1, only differing by a Thr to Pro substitution at position 3. APETx1 is believed to be a selective modulator of human ether-á-go-go related gene (hERG) potassium channels with a K(d) of 34 nM. In this study, APETx1, 2, and 3 have been subjected to an electrophysiological screening on a wide range of 24 ion channels expressed in Xenopus laevis oocytes: 10 cloned voltage-gated sodium channels (Na(V) 1.2-Na(V)1.8, the insect channels DmNa(V)1, BgNa(V)1-1a, and the arachnid channel VdNa(V)1) and 14 cloned voltage-gated potassium channels (K(V)1.1-K(V)1.6, K(V)2.1, K(V)3.1, K(V)4.2, K(V)4.3, K(V)7.2, K(V)7.4, hERG, and the insect channel Shaker IR). Surprisingly, the Thr3Pro substitution results in a complete abolishment of APETx3 modulation on hERG channels and provides this toxin the ability to become a potent (EC(50) 276 nM) modulator of voltage-gated sodium channels (Na(V)s) because it slows down the inactivation of mammalian and insect Na(V) channels. Our study also shows that the homologous toxins APETx1 and APETx2 display promiscuous properties since they are also capable of recognizing Na(V) channels with IC(50) values of 31 nM and 114 nM, respectively, causing an inhibition of the sodium conductance without affecting the inactivation. Our results provide new insights in key residues that allow these sea anemone toxins to recognize distinct ion channels with similar potency but with different modulatory effects. Furthermore, we describe for the first time the target promiscuity of a family of sea anemone toxins thus far believed to be highly selective. PMID:22972919

Peigneur, Steve; Béress, László; Möller, Carolina; Marí, Frank; Forssmann, Wolf-Georg; Tytgat, Jan

2012-12-01

105

Screening and cDNA Cloning of Kv1 Potassium Channel Toxins in Sea Anemones  

PubMed Central

When 21 species of sea anemones were screened for Kv1 potassium channel toxins by competitive inhibition of the binding of 125I-?-dendrotoxin to rat synaptosomal membranes, 11 species (two species of Actiniidae, one species of Hormathiidae, five species of Stichodactylidae and three species of Thalassianthidae) were found to be positive. Furthermore, full-length cDNAs encoding type 1 potassium channel toxins from three species of Stichodactylidae and three species of Thalassianthidae were cloned by a combination of RT-PCR, 3?RACE and 5?RACE. The precursors of these six toxins are commonly composed of signal peptide, propart and mature peptide portions. As for the mature peptide (35 amino acid residues), the six toxins share more than 90% sequence identities with one another and with ?1.3-SHTX-She1a (Shk) from Stichodactyla helianthus but only 34–63% identities with the other type 1 potassium channel toxins.

Yamaguchi, Yoshikazu; Hasegawa, Yuichi; Honma, Tomohiro; Nagashima, Yuji; Shiomi, Kazuo

2010-01-01

106

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

PubMed Central

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.

Sabogal-Arango, Angelica; Barreto, George E; Ramirez-Sanchez, David; Gonzalez-Mendoza, Juan; Barreto, Viviana; Morales, Ludis; Gonzalez, Janneth

2014-01-01

107

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

PubMed

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

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

2014-01-01

108

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

PubMed

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

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

2013-05-01

109

Edwardsiella andrillae, a new species of sea anemone from Antarctic ice.  

PubMed

Exploration of the lower surface of the Ross Ice Shelf in Antarctica by the Submersible Capable of under-Ice Navigation and Imaging (SCINI) remotely operated vehicle discovered a new species of sea anemone living in this previously undocumented ecosystem. This discovery was a significant outcome of the Coulman High Project's geophysical and environmental fieldwork in 2010-2011 as part of the ANDRILL (ANtarctic geologic DRILLing) program. Edwardsiella andrillae n. sp., lives with most of its column in the ice shelf, with only the tentacle crown extending into the seawater below. In addition to being the only Antarctic representative of the genus, Edwardsiella andrillae is distinguished from all other species of the genus in the number of tentacles and in the size and distribution of cnidae. The anatomy and histology of Edwardsiella andrillae present no features that explain how this animal withstands the challenges of life in such an unusual habitat. PMID:24349517

Daly, Marymegan; Rack, Frank; Zook, Robert

2013-01-01

110

New record of the sea anemone Kadosactis antarctica (Carlgren, 1928): re-description of an Antarctic deep-sea sea anemone, and a discussion of its generic and familial placement  

NASA Astrophysics Data System (ADS)

Sagartiogeton antarcticus Carlgren, 1928 is an Antarctic deep-sea species of sea anemone only known from its holotype. The species has been assigned to the genera Sagartiogeton and Kadosactis, and is currently placed within the family Kadosactidae Riemann-Zürneck, 1991. Kadosactis antarctica is re-described based on 11 specimens collected during the cruise of the R/V Polarstern ANT XIX/3 (ANDEEP-I) to the Scotia Sea and off the South Shetland Islands (Antarctica). The description includes a complete account of cnidae and photographs. Because the mesogloea is thickened on the aboral surface on the base of the tentacles, this feature becomes a generic character of Kadosactis rather than a differential specific character among the species of the genus as previously proposed. Furthermore, the known distribution of the species is enlarged to include the southern branch of the Scotia Sea.

Rodríguez, Estefanía; López-González, Pablo J.

2005-11-01

111

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

NASA Astrophysics Data System (ADS)

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.

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

2005-12-01

112

Anemone at the California rocky intertidal zone  

NSDL National Science Digital Library

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.

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

2007-01-04

113

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

PubMed Central

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.

Liu, Pin; Jo, Sooyeon

2012-01-01

114

The sea anemone toxin AdE-1 modifies both sodium and potassium currents of rat cardiomyocytes.  

PubMed

AdE-1, a cardiotonic peptide recently isolated from the sea anemone Aiptasia diaphana, contains 44 amino acids and has a molecular mass of 4907 Da. It was previously found to resemble other sea anemone type 1 and 2 Na+ channel toxins, enhancing contractions of rat cardiomyocytes and slowing their twitch relaxation; however, it did not induce spontaneous twitches. AdE-1 increased the duration of the cardiomyocyte action potential and decreased its amplitude and its time-to-peak in a concentration-dependent manner, without affecting its threshold and cell resting potential. Nor did it generate the early and delayed after-depolarizations characteristic of sea anemone Na+ channel toxins. To further understand its mechanism of action we investigated the effect of AdE-1 on the major ion currents of rat cardiomyocytes. In the present study we show that AdE-1 markedly slowed inactivation of the Na+ current, enhancing and prolonging the current influx with no effect on current activation, possibly through direct interaction with the site 3 receptor of the Na+ channel. No significant effect of AdE-1 on the Ca2+ current was observed, but, unexpectedly, AdE-1 significantly increased the amplitude of the transient component of the K+ current, shifting the current threshold to more negative membrane potentials. This effect on the K+ current has not been found in any other sea anemone toxin and may explain the exclusive reduction in action potential amplitude and the absence of the action potential disorders found with other toxins, such as early and delayed after-depolarizations. PMID:24749540

Nesher, Nir; Zlotkin, Eliahu; Hochner, Binyamin

2014-07-01

115

Subconductance states of single sodium channels modified by chloramine-T and sea anemone toxin in neuroblastoma cells  

Microsoft Academic Search

Single channel currents of chloramine-T (Chl-T) and sea anemone toxin (ATX-II) modified sodium channels were studied in neuroblastoma cells. With both substances similar subconductance states have been observed. The conductances of the sublevels were multiples of the “unit” step which was about onefourth of the most frequently occurring main conductance. Thus, the current levels observed were one fourth, half and

K. Nagy

1987-01-01

116

Mechanism of inactivation of single sodium channels after modification by chloramine-T, sea anemone toxin and scorpion toxin  

Microsoft Academic Search

Summary Single sodium-channel currents were measured in neuroblastoma cells after inhibition of inactivation by chloramine-T (CHL-T), sea anemone toxin II (ATX-II) and scorpion toxin (SCT). The decaying phase of the averaged single-channel currents recorded with 90-msec pulses in cell-attached patches was clearly slower than that of the unmodified channels, suggesting inhibition of macroscopic inactivation. Each substance caused repetitive openings and

Karoly Nagy

1988-01-01

117

The feeding habits of three Mediterranean sea anemone species, Anemonia viridis (Forskål), Actinia equina (Linnaeus) and Cereus pedunculatus (Pennant)  

Microsoft Academic Search

The feeding habits of the Mediterranean sea anemonesCereus pedunculatus, Actinia equina andAnemonia viridis were examined mainly by analysing their coelenteron contents. The three species are opportunistic omnivorous suspension feeders.\\u000a Main source of food forA. viridis andC. pedunculatus are crustaceans (mainly amphipods and decapods, respectively), while for the midlittoral speciesA. equina, it is organic detritus. Using the same method, the temporal

Ch. Chintiroglou; A. Koukouras

1992-01-01

118

Equistatin, a Protease Inhibitor from the Sea Anemone Actinia equina, Is Composed of Three Structural and Functional Domains  

Microsoft Academic Search

A cDNA encoding a precursor of equistatin, a potent cysteine and aspartic proteinase inhibitor, was isolated from the sea anemone Actinia equina. The deduced amino acid sequence of a 199-amino-acid residue mature protein with 20 cysteine residues, forming three structurally similar thyroglobulin type-1 domains, is preceded by a typical eukaryotic signal peptide. The mature protein region and those coding for

Borut Štrukelj; Brigita Lenar?i?; Kristina Gruden; Jože Punger?ar; Boris Rogelj; Vito Turk; Dirk Bosch; Maarten A Jongsma

2000-01-01

119

The importance of hemolysis in the lethal effects of equnatoxin II, a protein from the sea anemone Actinia equina (L.)  

Microsoft Academic Search

Equinatoxin II (EqT II) is one of the three isotoxins isolated from the sea anemone Actinia equina (L.). The cause of death due to i.v. application of Eq T II was attributed to its hemolytic activity and hiperkaliemia, and the direct cardio-respiratory effects of the toxin. The toxin also binds to plasma lipids and forms toxic conglomerates with them. In

Matjaž Bunc; Renata Bregar; Dušan Šuput

2000-01-01

120

Upgrades to StellaBase facilitate medical and genetic studies on the starlet sea anemone, Nematostella vectensis  

Microsoft Academic Search

The starlet sea anemone, Nematostella vectensis, is a basal metazoan organism that has recently emerged as an important model system in develop- mental biology and evolutionary genomics. StellaBase, the Nematostella Genomics Database (http:\\/\\/stellabase.org), was developed in 2005 as a resource to support the Nematostella research community. Recently, it has become apparent that Nematostella may be a particularly useful system for

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

2008-01-01

121

Mechanism of Membrane Permeabilization by Sticholysin I, a Cytolysin Isolated from the Venom of the Sea Anemone Stichodactyla helianthus †  

Microsoft Academic Search

Actinaria cytolysins are very potent basic toxins isolated from the venom of sea anemones, which are supposed to exert their toxic activity through formation of oligomeric pores in the host plasma membrane. To gain insight into their mechanism of action, the interaction of Stichodactyla helianthus sticholysin I (St-I) with lipid bilayers was studied. St-I increased the permeability of calcein-loaded lipid

Mayra Tejuca; Mauro Dalla Serra; Mercedes Ferreras; Maria E. Lanio; Gianfranco Menestrina

1996-01-01

122

Analgesic compound from sea anemone Heteractis crispa is the first polypeptide inhibitor of vanilloid receptor 1 (TRPV1).  

PubMed

Venomous animals from distinct phyla such as spiders, scorpions, snakes, cone snails, or sea anemones produce small toxic proteins interacting with a variety of cell targets. Their bites often cause pain. One of the ways of pain generation is the activation of TRPV1 channels. Screening of 30 different venoms from spiders and sea anemones for modulation of TRPV1 activity revealed inhibitors in tropical sea anemone Heteractis crispa venom. Several separation steps resulted in isolation of an inhibiting compound. This is a 56-residue-long polypeptide named APHC1 that has a Bos taurus trypsin inhibitor (BPTI)/Kunitz-type fold, mostly represented by serine protease inhibitors and ion channel blockers. APHC1 acted as a partial antagonist of capsaicin-induced currents (32 +/- 9% inhibition) with half-maximal effective concentration (EC(50)) 54 +/- 4 nm. In vivo, a 0.1 mg/kg dose of APHC1 significantly prolonged tail-flick latency and reduced capsaicin-induced acute pain. Therefore, our results can make an important contribution to the research into molecular mechanisms of TRPV1 modulation and help to solve the problem of overactivity of this receptor during a number of pathological processes in the organism. PMID:18579526

Andreev, Yaroslav A; Kozlov, Sergey A; Koshelev, Sergey G; Ivanova, Ekaterina A; Monastyrnaya, Margarita M; Kozlovskaya, Emma P; Grishin, Eugene V

2008-08-29

123

Isolation and characterisation of five neurotoxic and cardiotoxic polypeptides from the sea anemone Anthopleura elegantissima.  

PubMed

Five toxins (APE 1 to APE 5) of the sea anemone species Anthopleura elegantissima (Brandt) have been isolated from a toxic by-product fraction of its concentrated crude watery-methanolic extract, prepared previously for the isolation of a neuropeptide (the head-activator) by Schaller and Bodenmüller (Proc. Natl. Acad. Sci. USA 78 (1981) 7000) from 200kg sea anemones. Toxin purification was performed by desalting of the starting material by dialysis (MWCO 3500) against distilled water, anion exchange chromatography on QAE-Sephadex A25 at pH 8, twice gel filtration on Sephadex G50 m, repeated chromatography on QAE-Sephadex at pH 10 and chromatography on the cation exchanger Fractogel EMD SO(3)(-)-650 M.Final purification of the toxins was achieved by HPLC on MN SP 250/10 Nucleosil 500-5 C(18) PPN and MN SP 250/21 Nucleosil 300-7 C(18). Each toxin was composed of at least two isotoxins of which APE 1-1, APE 1-2, APE 2-1, APE 2-2 and APE 5-3 were isolated in preparative scale. With exception of APE 5-3 the sequences of the isotoxins have been elucidated. They resemble the 47 residue type-I long polypeptide toxins native to Anemonia sulcata (Pennant). All isotoxins paralyse the shore crab (Carcinus maenas) by tetanic contractions after i.m. application. The toxins modify current passing through the fast Na(+) channel in neuroblastoma cells, leading to delayed and incomplete inactivation. APE 1-1, APE 2-1 and APE 5-3 produce a positive inotropic effect in mammalian heart muscle, although they differ in potency. The order of potency is APE 2-1>APE 1-1>APE 5-3 (i.e. threshold concentrations are 1, 10 and 300nM, respectively). In addition, they enhance the spontaneous beating frequency in isolated right atria (guinea pig). The most potent cardiotoxic isotoxin is APE 2-1, its sequence is identical with that of AP-C, a toxin isolated and characterised previously by Norton et al. (Drugs and Foods from the Sea, 1978, University of Oklahoma Press, p. 37-50).LD50 APE 2-1:1 micro g/kg b.w. C. maenas (i.m.). LD50 APE 1-1:10 microg/kg b.w. C. maenas (i. m.). LD50 APE 5-3:50 microg/kg b.w. C. maenas (i.m.). PMID:11072049

Bruhn, T; Schaller, C; Schulze, C; Sanchez-Rodriguez, J; Dannmeier, C; Ravens, U; Heubach, J F; Eckhardt, K; Schmidtmayer, J; Schmidt, H; Aneiros, A; Wachter, E; Béress, L

2001-05-01

124

Outcomes of Infections of Sea Anemone Aiptasia pallida with Vibrio spp. Pathogenic to Corals.  

PubMed

Incidents of coral disease are on the rise. However, in the absence of a surrogate animal host, understanding of the interactions between coral pathogens and their hosts remains relatively limited, compared to other pathosystems of similar global importance. A tropical sea anemone, Aiptasia pallida, has been investigated as a surrogate model to study certain aspects of coral biology. Therefore, to test whether the utility of this surrogate model can be extended to study coral diseases, in the present study, we tested its susceptibility to common coral pathogens (Vibrio coralliilyticus and Vibrio shiloi) as well as polymicrobial consortia recovered from the Caribbean Yellow Band Disease (CYBD) lesions. A. pallida was susceptible to each of the tested pathogens. A. pallida responded to the pathogens with darkening of the tissues (associated with an increased melanization) and retraction of tentacles, followed by complete disintegration of polyp tissues. Loss of zooxanthellae was not observed; however, the disease progression pattern is consistent with the behavior of necrotizing pathogens. Virulence of some coral pathogens in Aiptasia was paralleled with their glycosidase activities. PMID:24619233

Zaragoza, William J; Krediet, Cory J; Meyer, Julie L; Canas, Gabriela; Ritchie, Kim B; Teplitski, Max

2014-08-01

125

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

PubMed

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

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

2014-01-01

126

Membrane insertion of the N-terminal ?-helix of equinatoxin II, a sea anemone cytolytic toxin  

PubMed Central

Equinatoxin II (Eqt-II) is a member of the actinoporins, a unique family of cytotoxins comprising 20 kDa pore-forming proteins isolated from sea anemones. Actinoporins bind preferentially to lipid membranes containing sphingomyelin, and create cation-selective pores by oligomerization of three to four monomers. Previous studies have shown that regions of Eqt-II crucial for its cytolytic mechanism are an exposed aromatic cluster and the N-terminal region containing an amphipathic ?-helix. In the present study, we have investigated the transfer of the N-terminal ?-helix into the lipid membrane by the use of three mutants containing an additional tryptophan residue in different positions within the amphipathic ?-helix (Ile18?Trp, Val22?Trp and Ala25?Trp). The interaction of the mutants with different model systems, such as lipid monolayers, erythrocytes and ghost membranes, was extensively characterized. Intrinsic fluorescence measurements and the use of vesicles containing brominated phospholipids indicated a deep localization of the N-terminal amphipathic helix in the lipid bilayer, except for the case of Val22?Trp. This mutant is stabilized in a state immediately prior to final pore formation. The introduction of additional tryptophan residues in the sequence of Eqt-II has proved to be a suitable approach to monitor the new environments that surround defined regions of the molecule upon membrane interaction.

2004-01-01

127

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

PubMed

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

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

128

Purification and Characterization of Gigantoxin-4, a New Actinoporin from the Sea Anemone Stichodactyla Gigantea  

PubMed Central

A new Cytolysin, termed as Gigantoxin-4, was isolated from the sea anemone Stichodactyla gigantea and found to be highly homologous with Cytolysin-3 (HMg III) from Heteractis magnifica, RTX-A from Radianthus macrodactylus, and Sticholysin-1 (St I) and Sticholysin-2 (St II) from Stichodactyla helianthus (homology 82%, 86%, 82% and 86% respectively). Its 20 N-terminal residues were identified and the full-length cDNA sequence was obtained by reverse transcription-polymerase chain reaction (RT-PCR). Multiple sequence alignments with other Cytolysins of the actinoporin family clearly indicated that Gigantoxin-4 belongs to this protein family. SDS-PAGE electrophoresis showed that this new actinoporin had a molecular mass of about 19 kDa, and possessed a high hemolytic activity to human erythrocytes (HA50= 40 ng/ml), which was inhibited by pre-incubation with sphingomyelin (SM) or SM-cholesterol mixtures. Our in vivo experiments showed that Gigantoxin-4 had wide toxicity to the rat cardiovascular system and the respiratory system. A concentration of 30?g/kg Gigantoxin-4, i.v. produced a positive inotropic effect on the rat heart although final cardiovascular failure was inevitable, and 60?g/kg Gigantoxin-4 caused respiratory arrest rapidly resulting in rat death. HE staining indicated pathological changes in various organs and tissues after i.v. administration of Gigantoxin-4.

Hu, Bo; Guo, Wei; Wang, Liang-hua; Wang, Jian-guang; Liu, Xiao-yu; Jiao, Bing-hua

2011-01-01

129

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

PubMed Central

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.

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

2014-01-01

130

Extensive genetic divergence between populations of the common intertidal sea anemone Actinia equina from Britain, the Mediterranean and the Cape Verde Islands  

Microsoft Academic Search

Samples of apparently similar red morphs of the common beadlet sea anemone Actinia equina (L.) were collected from rocky shores on the Isle of Man (Irish Sea), on the French Mediterranean coast near Marseille and\\u000a on the Cape Verde Island of Sal (off West Africa). For additional comparison an orange morph and the green A. prasina were also collected from

F. A. Monteiro; A. M. Solé-Cava; J. P. Thorpe

1997-01-01

131

Fatty acid and phospholipid syntheses are prerequisites for the cell cycle of Symbiodinium and their endosymbiosis within sea anemones.  

PubMed

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

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

2013-01-01

132

Viable algae released by the seastar Dermasterias imbricata feeding on the symbiotic sea anemone Anthopleura elegantissima  

Microsoft Academic Search

Echinoderms are major predators of anemones in temperate ecosystems. The fate of two algae, zooxanthellae and zoochlorellae,\\u000a after their host anemone (Anthopleura elegantissima Brandt) was consumed by the leather star Dermasterias imbricata Grube was determined in experiments conducted in July and August 2004. Productivity, photosynthetic pigments, and mitotic\\u000a index (percent of cells dividing) were used as indicators of algal health;

Sarah Bachman; Gisèle Muller-Parker

2007-01-01

133

Bacillus neizhouensis sp. nov., a halophilic marine bacterium isolated from a sea anemone.  

PubMed

A novel Gram-stain-positive, slightly halophilic, facultatively alkaliphilic, non-motile, catalase- and oxidase-positive, endospore-forming, rod-shaped, aerobic bacterium, strain JSM 071004(T), was isolated from a sea anemone collected from Neizhou Bay in the South China Sea. Growth occurred with 0.5-10 % (w/v) total salts (optimum 2-4 %) and at pH 6.5-10.0 (optimum pH 8.5) and 4-30 degrees C (optimum 25 degrees C). meso-Diaminopimelic acid was present in the cell-wall peptidoglycan. The predominant respiratory quinone was menaquinone 7 (MK-7) and the polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The major cellular fatty acids were anteiso-C(15 : 0) and iso-C(15 : 0). The genomic DNA G+C content was 39.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain JSM 071004(T) belongs to the genus Bacillus, being related most closely to the type strain of Bacillus agaradhaerens (sequence similarity 97.3 %), followed by the type strains of Bacillus cellulosilyticus (96.2 %), Bacillus clarkii (96.1 %) and Bacillus polygoni (96.0 %). The combination of phylogenetic analysis, DNA-DNA hybridization, phenotypic characteristics and chemotaxonomic data support the proposal that strain JSM 071004(T) represents a novel species of the genus Bacillus, for which the name Bacillus neizhouensis sp. nov. is proposed, with JSM 071004(T) (=CCTCC AB 207161(T) =DSM 19794(T) =KCTC 13187(T)) as the type strain. PMID:19643899

Chen, Yi-Guang; Zhang, Yu-Qin; Wang, Yong-Xia; Liu, Zhi-Xiong; Klenk, Hans-Peter; Xiao, Huai-Dong; Tang, Shu-Kun; Cui, Xiao-Long; Li, Wen-Jun

2009-12-01

134

Effect of High Ionic Strength and Inhibitors of H,K-ATPase on the Ouabain-Sensitive K- p-Nitrophenylphosphatase Activity in the Sea Anemone Stichodactyla helianthus  

Microsoft Academic Search

The ouabain-sensitive, K-stimulated p-nitrophenyl phosphatase (K-pNPPase) activity, an associated activity of the Na,K-ATPase, was assayed in tentacles of the sea anemone Stichodactyla helianthus to investigate the possibility that the sea anemone Na,K-ATPase activity is an associated activity of an H,K-ATPase. Activity was maximal at pH 6.5–7.0, decreasing only slightly in acidic medium but falling abruptly in alkaline medium to 60%

Susan Corey Specht; Cynthia Rodriguez; Luis Quiñones; Sonia Velazquez

1997-01-01

135

Isolation, characterization, and amino acid sequence of a polypeptide neurotoxin occurring in the sea anemone Stichodactyla helianthus.  

PubMed

An aqueous exudate collected from frozen and thawed bodies of a Caribbean sea anemone, Stichodactyla (formerly Stoichactis) helianthus, contained a polypeptide neurotoxin (Sh I) selectively toxic to crustaceans. The polypeptide was purified by G-50 Sephadex, phosphocellulose, and sulfopropyl-Sephadex chromatography and shown to have a molecular size of 5200 daltons and a pI of 8.3. The amino acid sequence determined by automatic Edman degradations of whole RCM Sh I and of its clostripain, staphylococcal protease, and cyanogen bromide digest peptides is A1ACKC5DDEGP10DIRTA15PLTGT20VDLGS25CNAGW30EKCAS35YYTII40ADCCR45KKK . Only 33% of this sequence is identical with the sequence of Anemonia sulcata toxin II, a sea anemone toxin isolated from the taxonomic family Actiniidae. The six half-cystines are located in equivalent positions to those of the actiniid toxins and account for nearly half of the residues common to all of the toxins. However, 69% of the Sh I sequence is identical with that of toxin II from Heteractis paumotensis, another sea anemone belonging to the family Stichodactylidae. Stichodactylid toxins lack the initial N-terminal residue of actiniid toxins and possess three consecutive acidic residues at positions 6-8, a single tryptophan at position 30, and four consecutive basic residues at positions 45-48 (C-terminus). A rabbit IgG prepared by Sh I immunization bound Sh I with a K0.5 of 4.7 nM but failed to bind homologous actiniid (Anemonia sulcata II, Condylactis gigantea III) or bolocerid (Bolocera tuedae II) polypeptide neurotoxins.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2568126

Kem, W R; Parten, B; Pennington, M W; Price, D A; Dunn, B M

1989-04-18

136

Separation and characterization of four different amino acid sequence variants of a sea anemone (Stichodactyla helianthus) protein cytolysin.  

PubMed

A basic protein cytolysin previously isolated from the Caribbean sea anemone Stichodactyla helianthus was shown by CM cellulose chromatography to consist of four isotoxins possessing different N-terminal amino acid sequences. These are designated as toxins I-IV in order of increasing isoelectric point. The estimated molecular sizes (17,400-18,200) of toxins I-III were very similar; toxins I and II posses one additional amino acid at their amino terminus relative to toxin III. Under denaturing conditions, toxin IV behaved as a significantly larger (19,600) polypeptide; Edman sequencing established that it possesses a seven residue extension at the N-terminal end relative to toxin III. None of the variants contained half-cystines or reducing sugars. Toxin III contributed 83% of the total purified cytolytic (hemolytic) activity, toxin II 14%, and the relatively insoluble toxins I and IV together only contributed about 3% of the total cytolytic activity. Cytolysin III lysed Ehrlich ascitic tumour cells, but when administered intraperitoneally in nonlethal doses to mice already inoculated with this tumour, it failed to protect the mice against the tumour. Comparison of the partial amino acid sequence of equinatoxin, another sea anemone protein cytolysin, with that of Stichodactyla cytolysin III indicates they are highly homologous. Many other cytolytic proteins isolated from sea anemones share these properties with Stichodactyla cytolysins: (1) selective inhibition of hemolytic activity by preincubation with sphingomyelin, (2) a molecular size of 10,000-20,000, and (3) an isoelectric point of 9 or above. PMID:2907688

Kem, W R; Dunn, B M

1988-01-01

137

The anticancer effects of actinoporin RTX-A from the sea anemone Heteractis crispa (=Radianthus macrodactylus)  

PubMed Central

Four isoforms of actinoporins were isolated in 2002-2004 from the tropical sea anemone Heteractis crispa (=Radianthus macrodactylus). Their potent hemolytic activities and effects on Ehrlich ascites carcinoma bearing mice were also studied. In this study, the individual actinoporin (RTX-A) demonstrated potential cancer-preventive activity at extremely low and non-cytotoxic concentrations. The substance suppressed the malignant transformation of mouse JB6 P+ Cl41 cells stimulated by epidermal growth factor (EGF) in soft agar with the inhibition of number of the colonies C50 (INCC50) = 0.034 nM. Actinoporin RTX-A also was shown to inhibit the phenotype expression of HeLa human cancer cells with an INCC50 = 0.03 nM. The cytotoxic effect of RTX-A against JB6 P+ Cl41 cells and HeLa, THP-1, MDA-MB-231, and SNU-C4 human tumor cell lines was high (IC50 = 0.57, 2.26, 1.11, 30.0 and 4.66 nM), but significantly less than their capacity to suppress tumor cell colony formation or phenotype expression. RTX-A also induced apoptosis and inhibited basal AP-1, NF-?B, and p53-dependent transcriptional activity in JB6 Cl41 cells. These results confirmed that actinoporin RTX-A from H. crispa, at least partially, might exhibit cancer-preventive and anticancer cytotoxic properties through the induction of p53-independent apoptosis and inhibition of the oncogenic AP-1 and NF-?B nuclear factors activity.

Fedorov, Sergey; Dyshlovoy, Sergey; Monastyrnaya, Margarita; Shubina, Larisa; Leychenko, Elena; Kozlovskaya, Emma; Jin, Jun-O; Kwak, Jong-Young; Bode, Ann M.; Dong, Zigang; Stonik, Valentin

2010-01-01

138

The behavior of sea anemone actinoporins at the water-membrane interface.  

PubMed

Actinoporins constitute a group of small and basic ?-pore forming toxins produced by sea anemones. They display high sequence identity and appear as multigene families. They show a singular behaviour at the water-membrane interface: In aqueous solution, actinoporins remain stably folded but, upon interaction with lipid bilayers, become integral membrane structures. These membranes contain sphingomyelin, display phase coexistence, or both. The water soluble structures of the actinoporins equinatoxin II (EqtII) and sticholysin II (StnII) are known in detail. The crystalline structure of a fragaceatoxin C (FraC) nonamer has been also determined. The three proteins fold as a ?-sandwich motif flanked by two ?-helices, one of them at the N-terminal end. Four regions seem to be especially important: A cluster of aromatic residues, a phosphocholine binding site, an array of basic amino acids, and the N-terminal ?-helix. Initial binding of the soluble monomers to the membrane is accomplished by the cluster of aromatic amino acids, the array of basic residues, and the phosphocholine binding site. Then, the N-terminal ?-helix detaches from the ?-sandwich, extends, and lies parallel to the membrane. Simultaneously, oligomerization occurs. Finally, the extended N-terminal ?-helix penetrates the membrane to build a toroidal pore. This model has been however recently challenged by the cryo-EM reconstruction of FraC bound to phospholipid vesicles. Actinoporins structural fold appears across all eukaryotic kingdoms in other functionally unrelated proteins. Many of these proteins neither bind to lipid membranes nor induce cell lysis. Finally, studies focusing on the therapeutic potential of actinoporins also abound. PMID:21621507

García-Ortega, Lucía; Alegre-Cebollada, Jorge; García-Linares, Sara; Bruix, Marta; Martínez-Del-Pozo, Alvaro; Gavilanes, José G

2011-09-01

139

Sea anemone peptide with uncommon ?-hairpin structure inhibits acid-sensing ion channel 3 (ASIC3) and reveals analgesic activity.  

PubMed

Three novel peptides were isolated from the venom of the sea anemone Urticina grebelnyi. All of them are 29 amino acid peptides cross-linked by two disulfide bridges, with a primary structure similar to other sea anemone peptides belonging to structural group 9a. The structure of the gene encoding the shared precursor protein of the identified peptides was determined. One peptide, ?-AnmTX Ugr 9a-1 (short name Ugr 9-1), produced a reversible inhibition effect on both the transient and the sustained current of human ASIC3 channels expressed in Xenopus laevis oocytes. It completely blocked the transient component (IC50 10 ± 0.6 ?M) and partially (48 ± 2%) inhibited the amplitude of the sustained component (IC50 1.44 ± 0.19 ?M). Using in vivo tests in mice, Ugr 9-1 significantly reversed inflammatory and acid-induced pain. The other two novel peptides, AnmTX Ugr 9a-2 (Ugr 9-2) and AnmTX Ugr 9a-3 (Ugr 9-3), did not inhibit the ASIC3 current. NMR spectroscopy revealed that Ugr 9-1 has an uncommon spatial structure, stabilized by two S-S bridges, with three classical ?-turns and twisted ?-hairpin without interstrand disulfide bonds. This is a novel peptide spatial structure that we propose to name boundless ?-hairpin. PMID:23801332

Osmakov, Dmitry I; Kozlov, Sergey A; Andreev, Yaroslav A; Koshelev, Sergey G; Sanamyan, Nadezhda P; Sanamyan, Karen E; Dyachenko, Igor A; Bondarenko, Dmitry A; Murashev, Arkadii N; Mineev, Konstantin S; Arseniev, Alexander S; Grishin, Eugene V

2013-08-01

140

Arrhythmogenic effect of a crude extract from sea anemone Condylactis gigantea: possible involvement of rErg1 channels.  

PubMed

Sea anemones possess a number of peptide toxins that target ion channels which provide powerful tools to study the molecular basis of diverse signaling pathways. It is also acknowledged that currents through Erg1 K(+) channels in cardiac myocytes are important for electrical stability of the heart and alterations in its activity has been linked to the onset of a potentially life-threatening heart condition named long QT syndrome type 2. Here, we report that a crude extract from sea anemone Condylactis gigantea significantly increases the QT interval and has arrhythmogenic effects in the rat heart. Furthermore, a bioassay-guided purification procedure allowed the isolation of a chromatographic fraction containing a major component with a molecular mass of 4478 Da from the crude extract, which causes a significant inhibition of whole-cell patch-clamp currents through recombinant Erg1 channels, responsible of the rapid delayed rectifying current crucial for electrical activity in the heart. Further studies could provide relevant information on the molecular mechanism of C. gigantea peptide toxins which represent promising tools in studying the physiology of diverse ion channels. PMID:23499927

Santos, Yúlica; Martínez, Martín; Sandoval, Alejandro; Rodríguez, Armando A; Falcón, Andrés; Heimer de la Cotera, Edgar P; Aguilar, Manuel B; Flores, Pedro; Felix, Ricardo; Arreguín, Roberto

2013-06-01

141

Intrinsic Tryptophan Fluorescence of Equinatoxin II, a PoreForming Polypeptide from the Sea Anemone Actinia Equina L, Monitors its Interaction with Lipid Membranes  

Microsoft Academic Search

Equinatoxin 11 is a cytolytic polypeptide from the sea anemone Actiniu equinu L. which forms pores in natural and artificial membranes. The intrinsic fluorescence of its five tryptophanyl residues was used to monitor the conformational changes induced by denaturing agents, pH and lipids. In the presence of denaturants, the emitted fluorescence peak, normally occurring at 335 nm, was reduced in

Peter Macek; Marialucia Zecchini; Cecilia Pederzolli; Mauro Dalla Serra; Gianfranco Menestrina

1995-01-01

142

Antibacterial Properties of Isolated Amoebocytes From the Sea Anemone Actinia equina  

Microsoft Academic Search

The antimicrobial defenses of anthozoans were investigated in vitro by extracting amoebocytes from the mesenteric filaments of the beadlet anemone, Actinia equina, and testing for their ability to phagocy- tose and kill the gram-negative bacterium Psychrobacter immobilis. Only the hyaline amoebocytes exhibited phagocytosis in vitro, with about 40% seen to ingest one or more bacteria over 45 min. Mixed cultures

DANIELLE M. C. HUTTON; VALERIE J. SMITH

1996-01-01

143

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

NASA Astrophysics Data System (ADS)

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.

Giusti, Michela; Innocenti, Carlo; Canese, Simonepietro

2014-06-01

144

Trioecy, a Unique Breeding Strategy in the Sea Anemone Aiptasia diaphana and Its Association with Sex Steroids.  

PubMed

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

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

2014-06-01

145

Metal accumulation and sublethal effects in the sea anemone, Aiptasia pallida, after waterborne exposure to metal mixtures.  

PubMed

The marine environment is subjected to contamination by a complex mixture of metals from various anthropogenic sources. Measuring the biological responses of organisms to a complex mixture of metals allows for examination of metal-specific responses in an environmentally realistic exposure scenario. To address this issue, the sea anemone, Aiptasia pallida was exposed to a control and a metal mixture (copper, zinc, nickel, and cadmium) at three exposure levels (10, 50, and 100 ?g/L) for 7 days. Anemones were then transferred to metal-free seawater for an additional 7 days after the metal exposure to assess metal depuration and recovery. Metal accumulation, activity of the enzymes catalase, glutathione reductase, and carbonic anhydrase, as well as, cell density of the symbiotic zooxanthellae were measured over 14 days. Metal accumulation in A. pallida occurred in a concentration dependent manner over the 7-day exposure period. Altered enzyme activity and tentacle retraction of the host, as well as decreased zooxanthellae cell density were observed responses over the 7 days, after exposure to a metal concentration as low as 10 ?g/L. Metal depuration and physiological recovery were dependent on both the metal and the exposure concentration. Understanding how A. pallida and their symbionts are affected by metal exposures in the laboratory may allow better understanding about the responses of symbiotic cnidarians in metal polluted aquatic environments. PMID:23845877

Brock, J R; Bielmyer, G K

2013-09-01

146

Symbiodinium diversity in the sea anemone Entacmaea quadricolor on the east Australian coast  

NASA Astrophysics Data System (ADS)

The diversity of Symbiodinium spp. in Entacmaea quadricolor was analysed from five locations along ~2,100 km on the east coast of Australia using denaturing gradient gel electrophoresis (DGGE) of the internal transcribed spacer 2 region (ITS2) combined with bacterial cloning. DGGE revealed that E. quadricolor predominantly associated with six types of clade C (four of which are novel) and that most anemones harboured multiple types simultaneously. Anemones from southern locations associated with a mixed assemblage of C25 and a variant of C3. This assemblage also dominated the central location, but was absent at the northern location. At central and northern sites, two novel variants of C42(type2) and C1 were found. Anemones hosting C42(type2) also showed a low abundance of variants of C3 and C1, and E1 was found in one sample, as revealed by bacterial cloning. The occurrence of geographically distinct ITS2 types or a consortium of types might reflect a need to optimise physiological performance of the symbiosis at different latitudes.

Pontasch, S.; Scott, A.; Hill, R.; Bridge, T.; Fisher, P. L.; Davy, S. K.

2014-06-01

147

The feeding habits of three Mediterranean sea anemone species, Anemonia viridis (Forskål), Actinia equina (Linnaeus) and Cereus pedunculatus (Pennant)  

NASA Astrophysics Data System (ADS)

The feeding habits of the Mediterranean sea anemones Cereus pedunculatus, Actinia equina and Anemonia viridis were examined mainly by analysing their coelenteron contents. The three species are opportunistic omnivorous suspension feeders. Main source of food for A. viridis and C. pedunculatus are crustaceans (mainly amphipods and decapods, respectively), while for the midlittoral species A. equina, it is organic detritus. Using the same method, the temporal and spatial changes in the diet of A. viridis were examined. During the whole year, crustaceans seem to be the main source of food for A. viridis. The diet composition of this species, however, differs remarkably in space, possibly reflecting the different composition of the macrobenthic organismic assemblages in different areas. The data collected are compared with the limited bibliographical information.

Chintiroglou, Ch.; Koukouras, A.

1992-03-01

148

Crystallization and preliminary crystallographic analysis of fragaceatoxin C, a pore-forming toxin from the sea anemone Actinia fragacea  

PubMed Central

Sea anemones produce water-soluble toxins that have the ability to interact with cell membranes and form pores within them. The mechanism of pore formation is based on an initial binding step followed by oligomerization and membrane insertion. Although the final structure of the pore remains unclear, biochemical studies indicate that it consists of a tetramer with a functional radius of ?1.1?nm. Since four monomers seem to be insufficient to build a pore of this size, the currently accepted model suggests that lipids might also participate in its structure. In this work, the crystallization and preliminary crystallographic analysis of two crystal forms of fragaceatoxin C (FraC), a newly characterized actinoporin from Actinia fragacea, are described. The crystals diffracted up to 1.8?Å resolution and the preliminary molecular-replacement solution supports an oligomeric structure of about 120?Å in diameter.

Mechaly, A. E.; Bellomio, A.; Morante, K.; Gonzalez-Manas, J. M.; Guerin, D. M. A.

2009-01-01

149

Digital marine bioprospecting: mining new neurotoxin drug candidates from the transcriptomes of cold-water sea anemones.  

PubMed

Marine bioprospecting is the search for new marine bioactive compounds and large-scale screening in extracts represents the traditional approach. Here, we report an alternative complementary protocol, called digital marine bioprospecting, based on deep sequencing of transcriptomes. We sequenced the transcriptomes from the adult polyp stage of two cold-water sea anemones, Bolocera tuediae and Hormathia digitata. We generated approximately 1.1 million quality-filtered sequencing reads by 454 pyrosequencing, which were assembled into approximately 120,000 contigs and 220,000 single reads. Based on annotation and gene ontology analysis we profiled the expressed mRNA transcripts according to known biological processes. As a proof-of-concept we identified polypeptide toxins with a potential blocking activity on sodium and potassium voltage-gated channels from digital transcriptome libraries. PMID:23170083

Urbarova, Ilona; Karlsen, Bård Ove; Okkenhaug, Siri; Seternes, Ole Morten; Johansen, Steinar D; Emblem, Ase

2012-10-01

150

A venom extract from the sea anemone Bartholomea annulata produces haemolysis and lipid peroxidation in mouse erythrocytes.  

PubMed

The haemolytic and peroxidative effects of crude extracts from Bartholomea annulata, a common Caribbean sea anemone, were investigated in erythrocytes isolated from NIH male albino mice. Significant concentration-dependent effects were found on both haemolysis (evaluated as release of haemoglobin) and lipid peroxidation (as a common index of oxidative damage to membrane lipids) in red blood cells. Moreover, the incubation of erythrocytes in the presence of either a general antioxidant, reduced glutathione (GSH, 50 microM), or an iron chelator, desferrioxamine (DFA, 10 microM), resulted in a significant attenuation of haemolysis in both cases. In light of these findings, the in vitro toxicological characterization of the venom, as well as the involvement of oxygen radical-mediated membrane damage as a potential mechanism of toxicity associated with haemolysis are discussed. PMID:11960675

Santamaría, Abel; Sánchez-Rodríguez, Judith; Zugasti, Alejandro; Martínez, Argelia; Galván-Arzate, Sonia; Segura-Puertas, Lourdes

2002-05-01

151

Digital Marine Bioprospecting: Mining New Neurotoxin Drug Candidates from the Transcriptomes of Cold-Water Sea Anemones  

PubMed Central

Marine bioprospecting is the search for new marine bioactive compounds and large-scale screening in extracts represents the traditional approach. Here, we report an alternative complementary protocol, called digital marine bioprospecting, based on deep sequencing of transcriptomes. We sequenced the transcriptomes from the adult polyp stage of two cold-water sea anemones, Bolocera tuediae and Hormathia digitata. We generated approximately 1.1 million quality-filtered sequencing reads by 454 pyrosequencing, which were assembled into approximately 120,000 contigs and 220,000 single reads. Based on annotation and gene ontology analysis we profiled the expressed mRNA transcripts according to known biological processes. As a proof-of-concept we identified polypeptide toxins with a potential blocking activity on sodium and potassium voltage-gated channels from digital transcriptome libraries.

Urbarova, Ilona; Karlsen, Bard Ove; Okkenhaug, Siri; Seternes, Ole Morten; Johansen, Steinar D.; Emblem, Ase

2012-01-01

152

Microinjection of mRNA or morpholinos for reverse genetic analysis in the starlet sea anemone, Nematostella vectensis.  

PubMed

We describe a protocol for microinjection of embryos for an emerging model system, the cnidarian sea anemone, Nematostella vectensis. In addition, we provide protocols for carrying out overexpression and knockdown of gene function through microinjection of in vitro-translated mRNAs or gene-specific oligonucleotide morpholinos (MOs), respectively. Our approach is simple, and it takes advantage of the natural adherence properties of the early embryo to position them in a single layer on a polystyrene dish. Embryos are visualized on a dissecting microscope equipped with epifluorescence and injected with microinjection needles using a picospritzer forced-air injection system. A micromanipulator is used to guide the needle to impale individual embryos. Injection takes ?1.5 h, and an experienced researcher can inject ?2,000 embryos in a single session. With the availability of the published Nematostella genome, the entire protocol, including cloning and transcription of mRNAs, can be carried out in ?1 week. PMID:23579781

Layden, Michael J; Röttinger, Eric; Wolenski, Francis S; Gilmore, Thomas D; Martindale, Mark Q

2013-05-01

153

Crystallization and preliminary crystallographic analysis of fragaceatoxin C, a pore-forming toxin from the sea anemone Actinia fragacea.  

PubMed

Sea anemones produce water-soluble toxins that have the ability to interact with cell membranes and form pores within them. The mechanism of pore formation is based on an initial binding step followed by oligomerization and membrane insertion. Although the final structure of the pore remains unclear, biochemical studies indicate that it consists of a tetramer with a functional radius of approximately 1.1 nm. Since four monomers seem to be insufficient to build a pore of this size, the currently accepted model suggests that lipids might also participate in its structure. In this work, the crystallization and preliminary crystallographic analysis of two crystal forms of fragaceatoxin C (FraC), a newly characterized actinoporin from Actinia fragacea, are described. The crystals diffracted up to 1.8 A resolution and the preliminary molecular-replacement solution supports an oligomeric structure of about 120 A in diameter. PMID:19342779

Mechaly, A E; Bellomio, A; Morante, K; González-Mañas, J M; Guérin, D M A

2009-04-01

154

Inhibition of voltage-gated Na+ currents in sensory neurones by the sea anemone toxin APETx2  

PubMed Central

BACKGROUND AND PURPOSE APETx2, a toxin from the sea anemone Anthropleura elegantissima, inhibits acid-sensing ion channel 3 (ASIC3)-containing homo- and heterotrimeric channels with IC50 values < 100 nM and 0.1–2 µM respectively. ASIC3 channels mediate acute acid-induced and inflammatory pain response and APETx2 has been used as a selective pharmacological tool in animal studies. Toxins from sea anemones also modulate voltage-gated Na+ channel (Nav) function. Here we tested the effects of APETx2 on Nav function in sensory neurones. EXPERIMENTAL APPROACH Effects of APETx2 on Nav function were studied in rat dorsal root ganglion (DRG) neurones by whole-cell patch clamp. KEY RESULTS APETx2 inhibited the tetrodotoxin (TTX)-resistant Nav 1.8 currents of DRG neurones (IC50, 2.6 µM). TTX-sensitive currents were less inhibited. The inhibition of Nav 1.8 currents was due to a rightward shift in the voltage dependence of activation and a reduction of the maximal macroscopic conductance. The inhibition of Nav 1.8 currents by APETx2 was confirmed with cloned channels expressed in Xenopus oocytes. In current-clamp experiments in DRG neurones, the number of action potentials induced by injection of a current ramp was reduced by APETx2. CONCLUSIONS AND IMPLICATIONS APETx2 inhibited Nav 1.8 channels, in addition to ASIC3 channels, at concentrations used in in vivo studies. The limited specificity of this toxin should be taken into account when using APETx2 as a pharmacological tool. Its dual action will be an advantage for the use of APETx2 or its derivatives as analgesic drugs.

Blanchard, Maxime G; Rash, Lachlan D; Kellenberger, Stephan

2012-01-01

155

BcsTx3 is a founder of a novel sea anemone toxin family of potassium channel blocker.  

PubMed

Sea anemone venoms have become a rich source of peptide toxins which are invaluable tools for studying the structure and functions of ion channels. In this work, BcsTx3, a toxin found in the venom of a Bunodosoma caissarum (population captured at the Saint Peter and Saint Paul Archipelago, Brazil) was purified and biochemically and pharmacologically characterized. The pharmacological effects were studied on 12 different subtypes of voltage-gated potassium channels (K(V)1.1-K(V)1.6; K(V)2.1; K(V)3.1; K(V)4.2; K(V)4.3; hERG and Shaker IR) and three cloned voltage-gated sodium channel isoforms (Na(V)1.2, Na(V)1.4 and BgNa(V)1.1) expressed in Xenopus laevis oocytes. BcsTx3 shows a high affinity for Drosophila Shaker IR channels over rKv1.2, hKv1.3 and rKv1.6, and is not active on NaV channels. Biochemical characterization reveals that BcsTx3 is a 50 amino acid peptide crosslinked by four disulfide bridges, and sequence comparison allowed BcsTx3 to be classified as a novel type of sea anemone toxin acting on K(V) channels. Moreover, putative toxins homologous to BcsTx3 from two additional actiniarian species suggest an ancient origin of this newly discovered toxin family. PMID:23895459

Orts, Diego J B; Moran, Yehu; Cologna, Camila T; Peigneur, Steve; Madio, Bruno; Praher, Daniela; Quinton, Loic; De Pauw, Edwin; Bicudo, José E P W; Tytgat, Jan; de Freitas, José C

2013-10-01

156

The Evolution of MicroRNA Pathway Protein Components in Cnidaria  

PubMed Central

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.

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

2013-01-01

157

Modeling habitat distribution from organism occurrences and environmental data: Case study using anemonefishes and their sea anemone hosts  

USGS Publications Warehouse

We demonstrate the KGSMapper (Kansas Geological Survey Mapper), a straightforward, web-based biogeographic tool that uses environmental conditions of places where members of a taxon are known to occur to find other places containing suitable habitat for them. Using occurrence data for anemonefishes or their host sea anemones, and data for environmental parameters, we generated maps of suitable habitat for the organisms. The fact that the fishes are obligate symbionts of the anemones allowed us to validate the KGSMapper output: we were able to compare the inferred occurrence of the organism to that of the actual occurrence of its symbiont. Characterizing suitable habitat for these organisms in the Indo-West Pacific, the region where they naturally occur, can be used to guide conservation efforts, field work, etc.; defining suitable habitat for them in the Atlantic and eastern Pacific is relevant to identifying areas vulnerable to biological invasions. We advocate distinguishing between these 2 sorts of model output, terming the former maps of realized habitat and the latter maps of potential habitat. Creation of a niche model requires adding biotic data to the environmental data used for habitat maps: we included data on fish occurrences to infer anemone distribution and vice versa. Altering the selection of environmental variables allowed us to investigate which variables may exert the most influence on organism distribution. Adding variables does not necessarily improve precision of the model output. KGSMapper output distinguishes areas that fall within 1 standard deviation (SD) of the mean environmental variable values for places where members of the taxon occur, within 2 SD, and within the entire range of values; eliminating outliers or data known to be imprecise or inaccurate improved output precision mainly in the 2 SD range and beyond. Thus, KGSMapper is robust in the face of questionable data, offering the user a way to recognize and clean such data. It also functions well with sparse datasets. These features make it useful for biogeographic meta-analyses with the diverse, distributed datasets that are typical for marine organisms lacking direct commercial value. ?? Inter-Research 2006.

Guinotte, J. M.; Bartley, J. D.; Iqbal, A.; Fautin, D. G.; Buddemeier, R. W.

2006-01-01

158

Isolation of L-3-phenyllactyl-Leu-Arg-Asn-NH sub 2 (Antho-RNamide), a sea anemone neuropeptide containing an unusual amino-terminal blocking group  

SciTech Connect

Using a radioimmunoassay for the carboxyl-terminal sequence Arg-Asn-NH{sub 2}, the authors have purified a peptide from acetic acid extracts of the sea anemone Anthopleura elegantissima. By classical amino acid analyses, mass spectrometry, and {sup 1}H NMR spectroscopy, the structure of this peptide was determined as 3-phenyllactyl-Leu-Arg-Asn-NH{sub 2}. By using reversed-phase HPLC and a chiral mobile phase, it was shown that the 3-phenyllactyl group had the L configuration. Immunocytochemical staining with antiserum against Arg-Asn-NH{sub 2} showed that L-3-phenyllactyl-Leu-Arg-Asn-NH{sub 2} (Antho-RNamide) was localized in neutrons of sea anemones. The L-3-phenyllactyl group has not been found earlier in neuropeptides of vertebrates or higher invertebrates. They propose that this residue renders Antho-RNamide resistant to nonspecific aminopeptidases, thereby increasing the stability of the peptide after neuronal release.

Grimmelikhuijzen, C.J.P.; Jacob, E.; Graff, D.; Reinscheid, R.K.; Nothacker, H.P. (Univ. of Hamburg (West Germany)); Rinehart, K.L.; Staley, A.L. (Univ. of Illinois, Urbana (USA))

1990-07-01

159

Cytotoxicity of equinatoxin II from the sea anemone Actinia equina involves ion channel formation and an increase in intracellular calcium activity  

Microsoft Academic Search

Summary Equinatoxin Il is a 20-kDa basic protein isolated from the sea anemoneActinia equina. The aim of our work was to investigate the primary molecular basis for the cytotoxic effects of equinatoxin II in two model systems: single bovine lactotrophs and planar lipid bilayers. Previous work has shown that equinatoxin II produces rapid changes in cell morphology, which are dependent

R. Zorec; M. TesterS; P. Maeekw; W. T. Mason

1990-01-01

160

Mechanism of action of equinatoxin II, a cytolysin from the sea anemone Actinia equina L. belonging to the family of actinoporins  

Microsoft Academic Search

Actinia equina equinatoxin II (EqT-II) is a representative of a family of pore-forming, basic, polypeptide toxins from sea anemones, now called actinoporins. This family comprises at least 27 members, which are all hemolytic at rather low concentrations. Red blood cell (RBC) hemolysis by EqT-II is the result of a colloid-osmotic shock caused by the opening of toxin- induced pores. Using

Peter Ma?ek; Giovanna Belmonte; Cecilia Pederzolli; Gianfranco Menestrina

1994-01-01

161

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

PubMed Central

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.

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

2012-01-01

162

Isolation and biological characterization of neurotoxic compounds from the sea anemone Lebrunia danae (Duchassaing and Michelotti, 1860).  

PubMed

This paper describes two neurotoxic proteins obtained from the Caribbean sea anemone Lebrunia danae. To assess the neurotoxic activity of the venom of L. danae, several bioassays were carried out, and to evaluate the effect of the toxin, Median Lethal Doses (LD(50)) were determined in vivo using sea crabs (Ocypode quadrata) and Artemia salina nauplii with the crude extract of the proportion of 2.82 mg/m. The proteins with neurotoxic effects were isolated using low-pressure liquid chromatography. The fractions containing the neurotoxic activity were analyzed by SDS-PAGE and showed protein bands with an apparent molecular weight of 62.50 kDa (LdNt1) and 58 kDa (LdNt2). To demonstrate that these proteins were indeed responsible for the neurotoxic activity observed, we injected a small fraction of the purified protein into the third walking leg of a crab and observed the typical convulsions, paralysis and death provoked by neurotoxins. Hemolytic activity was also tested for 0.238 mg of crude extract; the hemolytic value was 39.5, 49.6 and 50.1% for cow, sheep and pig erythrocytes, respectively. PMID:16474963

Sánchez-Rodríguez, J; Cruz-Vazquez, Karina

2006-07-01

163

Invasion and Persistence of a Selfish Gene in the Cnidaria  

PubMed Central

Background Homing endonuclease genes (HEGs) are superfluous, but are capable of invading populations that mix alleles by biasing their inheritance patterns through gene conversion. One model suggests that their long-term persistence is achieved through recurrent invasion. This circumvents evolutionary degeneration, but requires reasonable rates of transfer between species to maintain purifying selection. Although HEGs are found in a variety of microbes, we found the previous discovery of this type of selfish genetic element in the mitochondria of a sea anemone surprising. Methods/Principal Findings We surveyed 29 species of Cnidaria for the presence of the COXI HEG. Statistical analyses provided evidence for HEG invasion. We also found that 96 individuals of Metridium senile, from five different locations in the UK, had identical HEG sequences. This lack of sequence divergence illustrates the stable nature of Anthozoan mitochondria. Our data suggests this HEG conforms to the recurrent invasion model of evolution. Conclusions Ordinarily such low rates of HEG transfer would likely be insufficient to enable major invasion. However, the slow rate of Anthozoan mitochondrial change lengthens greatly the time to HEG degeneration: this significantly extends the periodicity of the HEG life-cycle. We suggest that a combination of very low substitution rates and rare transfers facilitated metazoan HEG invasion.

Goddard, Matthew R.; Leigh, Jessica; Roger, Andrew J; Pemberton, Andrew J

2006-01-01

164

Anemonefish oxygenate their anemone hosts at night.  

PubMed

Many stony coral-dwelling fishes exhibit adaptations to deal with hypoxia among the branches of their hosts; however, no information exists on the respiratory ecophysiology of obligate fish associates of non-coral organisms such as sea anemones and sponges. This study investigated metabolic and behavioral interactions between two-band anemonefish (Amphiprion bicinctus) and bulb-tentacle sea anemones (Entacmaea quadricolor) at night. We measured the net dark oxygen uptake ( , ?mol O2 h(-1)) of fish-anemone pairs when partners were separate from each other, together as a unit, and together as a unit but separated by a mesh screen that prevented physical contact. We also measured the effects of water current on sea anemone and quantified the nocturnal behaviors of fish in the absence and presence of host anemones in order to discern the impacts of anemone presence on fish behavior. Net of united pairs was significantly higher than that of both separated pairs and united pairs that were separated by a mesh screen. Anemone increased with flow rate from 0.5 to 2.0 cm s(-1), after which remained constant up to a water flow rate of 8.0 cm s(-1). Furthermore, the percentage time and bout frequency of flow-modulating behaviors by fish increased significantly when anemones were present. We conclude that physical contact between anemonefish and sea anemones elevates the of at least one of the partners at night, and anemonefish behavior at night appears to oxygenate sea anemone hosts and to augment the metabolism of both partners. PMID:23447664

Szczebak, Joseph T; Henry, Raymond P; Al-Horani, Fuad A; Chadwick, Nanette E

2013-03-15

165

Sticholysins, two pore-forming toxins produced by the Caribbean Sea anemone Stichodactyla helianthus: their interaction with membranes.  

PubMed

Sticholysins (Sts) I and II (StI/II) are pore-forming toxins (PFTs) produced by the Caribbean Sea anemone Stichodactyla helianthus belonging to the actinoporin family, a unique class of eukaryotic PFTs exclusively found in sea anemones. As for the rest of the members of this family, Sts are cysteine-less proteins, with molecular weights around 20 kDa, high isoelectric points (>9.5), and a preference for sphingomyelin-containing membranes. A three-dimensional structure of StII, solved by X-ray crystallography, showed that it is composed of a hydrophobic beta-sandwich core flanked on the opposite sides by two alpha helices comprising residues 14-23 and 128-135. A variety of experimental results indicate that the first thirty N-terminal residues, which include one of the helices, are directly involved in pore formation. This region contains an amphipathic stretch, well conserved in all actinoporins, which is the only portion of the molecule that can change conformation without perturbing the general protein fold; in fact, binding to model membranes only produces a slight increase in the regular secondary structure content of Sts. Sts are produced in soluble form but they readily bind to different cell and model membrane systems such as lipidic monolayers, micelles, and lipid vesicles. Remarkably, both the binding and pore-formation steps are critically dependent on the physico-chemical nature of the membrane. In fact, a large population of toxin irreversibly binds with high affinity in membranes containing sphingomyelin whereas binding in membranes lacking this sphingolipid is relatively low and reversible. The joint presence of SM and cholesterol largely promotes binding and pore formation. Minor amounts of lipids favoring a non-lamellar organization also augment the efficiency of pore formation. The functional pore formed in cellular and model membranes has a diameter of approximately 2.0 nm and is presumably formed by the N-terminal alpha helices of four monomers tilted 31 degrees in relation to the bilayer normal. Experimental evidence supports the hypothesis that sticholysins, as well as equinatoxin II, another actinoporin, form a toroidal pore in membranes in which the polypeptide chains as well as the polar head groups of phospholipids are involved. PMID:19268489

Alvarez, Carlos; Mancheño, José M; Martínez, Diana; Tejuca, Mayra; Pazos, Fabiola; Lanio, María E

2009-12-15

166

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

Microsoft Academic Search

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

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

1986-01-01

167

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

PubMed

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

Rahman, Taufiq; Smith, Ewan St John

2014-07-18

168

Internal brooding favours pre-metamorphic chimerism in a non-colonial cnidarian, the sea anemone Urticina felina.  

PubMed

The concept of intraorganismal genetic heterogeneity resulting from allogeneic fusion (i.e. chimerism) has almost exclusively been explored in modular organisms that have the capacity to reproduce asexually, such as colonial ascidians and corals. Apart from medical conditions in mammals, the natural development of chimeras across ontogenetic stages has not been investigated in any unitary organism incapable of asexual propagation. Furthermore, chimerism was mainly studied among gregarious settlers to show that clustering of genetically similar individuals upon settlement promotes the occurrence of multi-chimeras exhibiting greater fitness. The possible occurrence of chimeric embryos and larvae prior to settlement has not received any attention. Here we document for the first time the presence of natural chimeras in brooded embryos and larvae of a unitary cnidarian, the sea anemone Urticina felina. Rates of visible bi- and multi-chimerism of up to 3.13 per cent were measured in the broods of 16 females. Apart from these sectorial chimeras, monitored fusion events also yielded homogeneous chimeric entities (mega-larvae) suggesting that the actual rates of natural chimerism in U. felina are greater than predicted by visual assessment. In support of this assumption, the broods of certain individuals comprised a dominant proportion (to 90%) of inexplicably large embryos and larvae (relative to oocyte size). Findings of fusion and chimerism in a unitary organism add a novel dimension to the framework within which the mechanisms and evolutionary significance of genetic heterogeneity in animal taxa can be explored. PMID:21508035

Mercier, Annie; Sun, Zhao; Hamel, Jean-François

2011-12-01

169

Analogs of the Sea Anemone Potassium Channel Blocker ShK for the Treatment of Autoimmune Diseases  

PubMed Central

CCR7? effector memory T (TEM) lymphocytes are involved in autoimmune diseases such as multiple sclerosis, type 1 diabetes mellitus and rheumatoid arthritis. These cells express Kv1.3 potassium channels that play a major role in their activation. Blocking these channels preferentially inhibits the activation of CCR7? TEM cells, with little or no effects on CCR7+ naïve and central memory T cells. Blockers of lymphocyte Kv1.3 channels therefore show considerable potential as therapeutics for autoimmune diseases. ShK, a 35-residue polypeptide isolated from the Caribbean sea anemone Stichodactyla helianthus, blocks Kv1.3 channels at picomolar concentrations. Although ShK was effective in treating rats with delayed type hypersensitivity and a model of multiple sclerosis, it lacks selectivity for Kv1.3 channels over closely-related Kv1 channels. Extensive mutagenesis studies combined with elucidation of the structure of ShK led to models of ShK docked with the channel. This knowledge was valuable in the development of new ShK analogs with improved selectivity and increasing stability, which have proven efficacious in preventing and/or treating animal models of delayed type hypersensitivity, type 1 diabetes, rheumatoid arthritis, and multiple sclerosis without inducing generalized immunosuppression. They are currently undergoing further evaluation as potential immunomodulators for the treatment of autoimmune diseases.

Beeton, Christine; Pennington, Michael W.; Norton, Raymond S.

2012-01-01

170

The NMR solution structure of a Kunitz-type proteinase inhibitor from the sea anemone Stichodactyla helianthus.  

PubMed

The solution structure of a 55-amino-acid Kunitz-type proteinase inhibitor, ShPI, purified from the Caribbean sea anemone Stichodactyla helianthus, was determined by NMR spectroscopy. Nearly complete sequence-specific 1H-NMR assignments were obtained at pH 4.6 and 36 degrees C, and stereo-specific assignments were determined for 23 pairs of diastereotopic substituents. A data set of 666 upper distance limit constraints and 122 dihedral angle constraints collected on this basis was used as input for a structure calculation with the program DIANA. Following energy minimization with the program OPAL, the average root-mean-square diviation (RMSD) of the 20 DIANA conformers used to represent the solution structure relative to the mean structure is 61 pm for all backbone atoms N, C alpha and C', and 106 pm for all heavy atoms of residues 2-53. This high-quality solution structure of ShPI has a nearly identical molecular architecture as the bovine pancreatic trypsin inhibitor (BPTI), despite a mere 35% of sequence similarity between the two proteins. Exchange rates measured for 48 out of the 51 backbone amide protons showed that the positions of 20 slowly exchanging amide protons correlate well with hydrogen bonds involving these protons in the energy-minimized solution structure. The solution structure of ShPI is compared to the four homologous proteins for which the three-dimensional structure is also available. PMID:8462542

Antuch, W; Berndt, K D; Chávez, M A; Delfín, J; Wüthrich, K

1993-03-15

171

Analogs of the sea anemone potassium channel blocker ShK for the treatment of autoimmune diseases.  

PubMed

CCR7- effector memory T (TEM) lymphocytes are involved in autoimmune diseases such as multiple sclerosis, type 1 diabetes mellitus and rheumatoid arthritis. These cells express Kv1.3 potassium channels that play a major role in their activation. Blocking these channels preferentially inhibits the activation of CCR7- TEM cells, with little or no effects on CCR7+ naïve and central memory T cells. Blockers of lymphocyte Kv1.3 channels therefore show considerable potential as therapeutics for autoimmune diseases. ShK, a 35-residue polypeptide isolated from the Caribbean sea anemone Stichodactyla helianthus, blocks Kv1.3 channels at picomolar concentrations. Although ShK was effective in treating rats with delayed type hypersensitivity and a model of multiple sclerosis, it lacks selectivity for Kv1.3 channels over closely-related Kv1 channels. Extensive mutagenesis studies combined with elucidation of the structure of ShK led to models of ShK docked with the channel. This knowledge was valuable in the development of new ShK analogs with improved selectivity and increasing stability, which have proven efficacious in preventing and/or treating animal models of delayed type hypersensitivity, type 1 diabetes, rheumatoid arthritis, and multiple sclerosis without inducing generalized immunosuppression. They are currently undergoing further evaluation as potential immunomodulators for the treatment of autoimmune diseases. PMID:21824083

Beeton, Christine; Pennington, Michael W; Norton, Raymond S

2011-10-01

172

Changes in microbial communities associated with the sea anemone Anemonia viridis in a natural pH gradient.  

PubMed

Ocean acidification, resulting from rising atmospheric carbon dioxide concentrations, is a pervasive stressor that can affect many marine organisms and their symbionts. Studies which examine the host physiology and microbial communities have shown a variety of responses to the ocean acidification process. Recently, several studies were conducted based on field experiments, which take place in natural CO(2) vents, exposing the host to natural environmental conditions of varying pH. This study examines the sea anemone Anemonia viridis which is found naturally along the pH gradient in Ischia, Italy, with an aim to characterize whether exposure to pH impacts the holobiont. The physiological parameters of A. viridis (Symbiodinium density, protein, and chlorophyll a+c concentration) and its microbial community were monitored. Although reduction in pH was seen to have had an impact on composition and diversity of associated microbial communities, no significant changes were observed in A. viridis physiology, and no microbial stress indicators (i.e., pathogens, antibacterial activity, etc.) were detected. In light of these results, it appears that elevated CO(2) does not have a negative influence on A. viridis that live naturally in the site. This suggests that natural long-term exposure and dynamic diverse microbial communities may contribute to the acclimation process of the host in a changing pH environment. PMID:23011286

Meron, Dalit; Buia, Maria-Cristina; Fine, Maoz; Banin, Ehud

2013-02-01

173

Membrane insertion of the N-terminal alpha-helix of equinatoxin II, a sea anemone cytolytic toxin.  

PubMed

Equinatoxin II (Eqt-II) is a member of the actinoporins, a unique family of cytotoxins comprising 20 kDa pore-forming proteins isolated from sea anemones. Actinoporins bind preferentially to lipid membranes containing sphingomyelin, and create cation-selective pores by oligomerization of three to four monomers. Previous studies have shown that regions of Eqt-II crucial for its cytolytic mechanism are an exposed aromatic cluster and the N-terminal region containing an amphipathic alpha-helix. In the present study, we have investigated the transfer of the N-terminal alpha-helix into the lipid membrane by the use of three mutants containing an additional tryptophan residue in different positions within the amphipathic alpha-helix (Ile18-->Trp, Val22-->Trp and Ala25-->Trp). The interaction of the mutants with different model systems, such as lipid monolayers, erythrocytes and ghost membranes, was extensively characterized. Intrinsic fluorescence measurements and the use of vesicles containing brominated phospholipids indicated a deep localization of the N-terminal amphipathic helix in the lipid bilayer, except for the case of Val22-->Trp. This mutant is stabilized in a state immediately prior to final pore formation. The introduction of additional tryptophan residues in the sequence of Eqt-II has proved to be a suitable approach to monitor the new environments that surround defined regions of the molecule upon membrane interaction. PMID:15317486

Gutiérrez-Aguirre, Ion; Barlic, Ariana; Podlesek, Zdravko; Macek, Peter; Anderluh, Gregor; González-Mañas, Juan M

2004-12-01

174

Purification, cloning and characterization of fragaceatoxin C, a novel actinoporin from the sea anemone Actinia fragacea.  

PubMed

Actinia fragacea is commonly called the "strawberry" anemone because of the distinctive yellow or green spots displayed on its red column. Its venom contains several haemolytic proteins with a molecular mass of approximately 20 kDa that can be separated by ion-exchange column chromatography. One of them was purified to homogeneity and was named fragaceatoxin C (FraC). Its 15 N-terminal residues were identified by Edman degradation and served to obtain its complete DNA coding sequence by RT-PCR. The coding region of FraC was amplified and cloned in the expression vector pBAT-4. Purified recombinant FraC consists of 179 amino acids and multiple sequence alignment with other actinoporins clearly indicates that FraC belongs to this protein family. The secondary structure, thermal stability and lytic activity of native and recombinant FraC were practically identical and exhibit the same basic features already described for equinatoxin-II and sticholysin-II. PMID:19563820

Bellomio, Augusto; Morante, Koldo; Barlic, Ariana; Gutiérrez-Aguirre, Ion; Viguera, Ana Rosa; González-Mañas, Juan Manuel

2009-11-01

175

Pelagia benovici sp. nov. (Cnidaria, Scyphozoa): a new jellyfish in the Mediterranean Sea.  

PubMed

A bloom of an unknown semaestome jellyfish species was recorded in the North Adriatic Sea from September 2013 to early 2014. Morphological analysis of several specimens showed distinct differences from other known semaestome species in the Mediterranean Sea and unquestionably identified them as belonging to a new pelagiid species within genus Pelagia. The new species is morphologically distinct from P. noctiluca, currently the only recognized valid species in the genus, and from other doubtful Pelagia species recorded from other areas of the world. Molecular analyses of mitochondrial cytochrome c oxidase subunit I (COI) and nuclear 28S ribosomal DNA genes corroborate its specific distinction from P. noctiluca and other pelagiid taxa, supporting the monophyly of Pelagiidae. Thus, we describe Pelagia benovici sp. nov. Piraino, Aglieri, Scorrano & Boero. PMID:24870334

Piraino, Stefano; Aglieri, Giorgio; Martell, Luis; Mazzoldi, Carlotta; Melli, Valentina; Milisenda, Giacomo; Scorrano, Simonetta; Boero, Ferdinando

2014-01-01

176

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

PubMed

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

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

2013-01-01

177

The influence of UV radiation on number and ultrastructure of the endosymbiotic dinoflagellates in the sea anemone Cereus pedunculatus (Anthozoa: Actiniaria)  

NASA Astrophysics Data System (ADS)

The sea anemone Cereus pedunculatus was artificially UV-irradiated to test the effect of UV-light on the number of endosymbiotic dinoflagellates in its gastrodermis and on their ultrastructure. Anemones were kept in the laboratory in a light: dark cycle (LD 12?12; 13 W m-2) at 18 °C and briefly (2, 5 and 9 d) exposed to UV radiation at quasisolar intensities, 0.5 or 1 W m-2. Their tentacles were then examined in the electron microscope for qualitative and quantitative changes in the zooxanthellae. There was an intensity-dependent decrease in the number of symbionts, which in some cases were lost altogether (bleaching). Irradiated anemones contained a larger proportion of symbionts with ultrastructural abnormalities, namely diminished starch, some mitochondria with altered matrix and, in particular, characteristic changes in the chloroplasts; instead of being densely stacked, the thylakoids were spread apart and swollen at the ends of their membranes to form vesicle-like structures. Relatively large vesicles also appeared in the cytoplasm. The resulting enlargement of the whole dinoflagellate cell was documented morphometrically. Another intensity-dependent effect was a significant decrease in mitosis rate, established by counting dividing symbiont cells in TEM micrographs. *** DIRECT SUPPORT *** A03B6037 00006

Hannack, K.; Kestler, P.; Sicken, O.; Westheide, W.

1998-02-01

178

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

PubMed

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

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

2013-11-01

179

Mechanical and electrophysiological effects of sea anemone (Anemonia sulcata) toxins on rat innervated and denervated skeletal muscle.  

PubMed Central

1 Some effects of the sea-anemone toxin ATX-II on mammalian nerve-muscle preparations have been described. 2 When ATX-II (10(-8)-10(-6) M) was applied to rat hemidiaphragm preparations, both directly and indirectly generated twitch responses were potentiated and prolonged. At the same time the resting tension of the preparations increased. 3 The increase in resting tension caused by ATX-II in innervated muscles was not prevented by curarization, but was reversed by exposure to tetrodotoxin. The increase in denervated muscles was not completely reversed by tetrodotoxin. 4 At concentrations exceeding 1 x 10(-7) M, ATX-II caused a sodium-dependent depolarization of both normal and denervated muscles. The depolarization of the denervated muscles was only partially reversed by tetrodotoxin. 5 In the presence of ATX-II repetitive endplate potentials (e.p.ps) were evoked by single shocks to the motor nerves in many fibres, and in those in which a single e.p.p. was still observed, the quantum content (m) was increased. Miniature e.p.p. frequency was not increased by ATX-II, even when muscle fibres were depolarized by 30 mV. 6 The indirectly and directly elicited action potentials of normal and denervated muscle fibres were much prolonged by ATX-II. The action potentials remained sodium-dependent. The sodium-dependent tetrodotoxin-resistant action potential of the denervated muscle fibre was also prolonged by ATX-II. 7 It is concluded that ATX-II both activates, and delays inactivation of, sodium channels in mammalian skeletal muscle fibres, probably in interacting with the channel "gate'.

Alsen, C.; Harris, J. B.; Tesseraux, I.

1981-01-01

180

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

PubMed Central

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.

2012-01-01

181

Reproduction in two deep-sea anemones (Actiniaria); Phelliactis hertwigi and P. robusta  

NASA Astrophysics Data System (ADS)

Bathymetric distribution, abundance, substrate choice and gametogenesis have been investigated in two species of deep-sea actiniarians found in the northeast Atlantic Ocean. Phelliactis hertwigi occurs at 719-1448m in the Porcupine Seabight, usually encloses a bolus of sediment within its highly concave pedal disc (79.7%), and has abundances of up to 14.5 individuals 1000m -2. Phelliactis robusta occurs at 1600-2173m in the Porcupine Seabight, but extends deeper in the Bay of Biscay. In areas of soft sediment it is associated strongly with clinker (92.7%) and attains densities of 2.9 individuals 1000m -2. Both species are dioecious. Their sperm appear similar to those of the related intertidal Calliactis spp. Previtellogenesis and vitellogenesis of the oocytes have been defined by ultrastructural and histochemical studies. In P. hertwigi mature oocytes measure up to 180?m, and to 210?m in P. robusta. In P. hertwigi oogenesis takes 8-9 months, with spawning in October/November, whereas in the deeper-living P. robusta oogenesis occupies 15 to 19 months and spawning occurs in April/ May. Evidence is produced to suggest that these two contrasting cycles are related to the rate and seasonality of deposition of organic matter to the deep-sea floor.

van Praët, M.; Rice, A. L.; Thurston, M. H.

182

Molecular analysis of the sea anemone toxin Av3 reveals selectivity to insects and demonstrates the heterogeneity of receptor site-3 on voltage-gated Na+ channels  

PubMed Central

Av3 is a short peptide toxin from the sea anemone Anemonia viridis shown to be active on crustaceans and inactive on mammals. It inhibits inactivation of Navs (voltage-gated Na+ channels) like the structurally dissimilar scorpion ?-toxins and type I sea anemone toxins that bind to receptor site-3. To examine the potency and mode of interaction of Av3 with insect Navs, we established a system for its expression, mutagenized it throughout, and analysed it in toxicity, binding and electrophysiological assays. The recombinant Av3 was found to be highly toxic to blowfly larvae (ED50=2.65±0.46 pmol/100 mg), to compete well with the site-3 toxin Lqh?IT (from the scorpion Leiurus quinquestriatus) on binding to cockroach neuronal membranes (Ki=21.4±7.1 nM), and to inhibit the inactivation of Drosophila melanogaster channel, DmNav1, but not that of mammalian Navs expressed in Xenopus oocytes. Moreover, like other site-3 toxins, the activity of Av3 was synergically enhanced by ligands of receptor site-4 (e.g. scorpion ?-toxins). The bioactive surface of Av3 was found to consist mainly of aromatic residues and did not resemble any of the bioactive surfaces of other site-3 toxins. These analyses have portrayed a toxin that might interact with receptor site-3 in a different fashion compared with other ligands of this site. This assumption was corroborated by a D1701R mutation in DmNav1, which has been shown to abolish the activity of all other site-3 ligands, except Av3. All in all, the present study provides further evidence for the heterogeneity of receptor site-3, and raises Av3 as a unique model for design of selective anti-insect compounds.

Moran, Yehu; Kahn, Roy; Cohen, Lior; Gur, Maya; Karbat, Izhar; Gordon, Dalia; Gurevitz, Michael

2007-01-01

183

Effects of lipid composition on membrane permeabilization by sticholysin I and II, two cytolysins of the sea anemone Stichodactyla helianthus.  

PubMed Central

Sticholysin I and II (St I and St II), two basic cytolysins purified from the Caribbean sea anemone Stichodactyla helianthus, efficiently permeabilize lipid vesicles by forming pores in their membranes. A general characteristic of these toxins is their preference for membranes containing sphingomyelin (SM). As a consequence, vesicles formed by equimolar mixtures of SM with phosphatidylcholine (PC) are very good targets for St I and II. To better characterize the lipid dependence of the cytolysin-membrane interaction, we have now evaluated the effect of including different lipids in the composition of the vesicles. We observed that at low doses of either St I or St II vesicles composed of SM and phosphatidic acid (PA) were permeabilized faster and to a higher extent than vesicles of PC and SM. As in the case of PC/SM mixtures, permeabilization was optimal when the molar ratio of PA/SM was ~1. The preference for membranes containing PA was confirmed by inhibition experiments in which the hemolytic activity of St I was diminished by pre-incubation with vesicles of different composition. The inclusion of even small proportions of PA into PC/SM LUVs led to a marked increase in calcein release caused by both St I and St II, reaching maximal effect at ~5 mol % of PA. Inclusion of other negatively charged lipids (phosphatidylserine (PS), phosphatidylglycerol (PG), phosphatidylinositol (PI), or cardiolipin (CL)), all at 5 mol %, also elicited an increase in calcein release, the potency being in the order CL approximately PA >> PG approximately PI approximately PS. However, some boosting effect was also obtained, including the zwitterionic lipid phosphatidylethanolamine (PE) or even, albeit to a lesser extent, the positively charged lipid stearylamine (SA). This indicated that the effect was not mediated by electrostatic interactions between the cytolysin and the negative surface of the vesicles. In fact, increasing the ionic strength of the medium had only a small inhibitory effect on the interaction, but this was actually larger with uncharged vesicles than with negatively charged vesicles. A study of the fluidity of the different vesicles, probed by the environment-sensitive fluorescent dye diphenylhexatriene (DPH), showed that toxin activity was also not correlated to the average membrane fluidity. It is suggested that the insertion of the toxin channel could imply the formation in the bilayer of a nonlamellar structure, a toroidal lipid pore. In this case, the presence of lipids favoring a nonlamellar phase, in particular PA and CL, strong inducers of negative curvature in the bilayer, could help in the formation of the pore. This possibility is confirmed by the fact that the formation of toxin pores strongly promotes the rate of transbilayer movement of lipid molecules, which indicates local disruption of the lamellar structure.

Valcarcel, C A; Dalla Serra, M; Potrich, C; Bernhart, I; Tejuca, M; Martinez, D; Pazos, F; Lanio, M E; Menestrina, G

2001-01-01

184

Molluscicidal activities of aqueous extract of the sea anemone Parasicyonis actinostoloides against vector snails Bulinus truncatus and Lymnaea natalensis.  

PubMed

The aqueous extract of the sea anemone Parasicyonis actinostoloides showed molluscicidal effect against vector snails of Schistosoma hacematobium and Fasciola gigantica after 24 hours of exposure. LC50) and LC90 values for P. actinostoloides were 40 & 78.6 ppm for B. runcatus and 46.6 & 86.5 ppm for L. natalensis respectively. The effect of continuously exposure of B. truncatits and L. naltlensis to sublethal aqueous extract concentrations (LC0, LC10 & LC25) on survival rate, egg production and on infectivity of miracidia to infection with S. haematobium and F. gigantica were studied. The data showed that no B. truncatus survived more than 42, 32 & 27 days after exposure with a mean life span of 18.5, 13.3 & 11.1 days respectively. The death rate of B. truncatus with LC0 was highly significant as compared to treatment with LC10 & LC25 (p < 0.01). L. natalensis were more susceptible to the effect of aqueous extract than B. truncatus. LC0, LC10 & LC25, extract killed all L. natalensis through 32, 27 & 22 days. The mean life span of those exposed to LC0 was 12.37 days, high significant when compared with treated LC10 & LC25 ones (p < 0.01). The cumulative mortality rates of B. truncatus and L. natalensis in controls during the experimental study (52 days) was 60% & 75%, respectively. Egg production of B. truncatius and L. natalensis was not affected by sublethal concentrations. Control snails layed significantly higher no. of eggs than treated ones. B. truncatus stopped egg laying 17 days after exposure to LC25. those treated with LC10 & LC0 ceased to deposit eggs after 22 & 27 days respectively. The percent reduction in egg laying capacity of B. truncatus treated with LC0, LC10 & LC25 compared to controls was 77.1%, 93.2% & 92.8% respectively (p < 0.01). Similar reduction in egg production of treated L. natalensis cornpared to controls occurred, the percent reduction in egg production of snails treated with LC0, LC10 & LC25 in relation to controls was 78.4%, 92.4% & 94.7% respectively. Sublethal concentrations of aqueous extract of P. actinostoloides affected hatchability of B. truncatus and L. natalensis eggs. The data showed that eggs of B. truncatus and L. natalensis can hatch in all tested concentrations but with different rates. The eggs' hatchability in snails exposed to LC0, LCIo & LC25 extract at 5 days old was 44%, 38% & 30% in B. truncatus respectively. In L. natalensis eggs, the corresponding rates were lower 28%, 24% & 18% respectively. The infection of B. truncatuts and L. natalensis with S. haematobium n and F. giganlica miracidia was greatly reduced by the sublethal concentrations of aqueous extract of P. actinostoloides. The reduction of infection rate increased with the increased of sublethal concentrations. In B. truncatus the reduction was 43.2%, 57.6% & 76.6% compared to controls and in L. natalensis was 56.3%, 70.2% & 77.4%, respectively. PMID:16927866

el-Sayed, Kamelia Abass

2006-08-01

185

Effects of lipid composition on membrane permeabilization by sticholysin I and II, two cytolysins of the sea anemone Stichodactyla helianthus.  

PubMed

Sticholysin I and II (St I and St II), two basic cytolysins purified from the Caribbean sea anemone Stichodactyla helianthus, efficiently permeabilize lipid vesicles by forming pores in their membranes. A general characteristic of these toxins is their preference for membranes containing sphingomyelin (SM). As a consequence, vesicles formed by equimolar mixtures of SM with phosphatidylcholine (PC) are very good targets for St I and II. To better characterize the lipid dependence of the cytolysin-membrane interaction, we have now evaluated the effect of including different lipids in the composition of the vesicles. We observed that at low doses of either St I or St II vesicles composed of SM and phosphatidic acid (PA) were permeabilized faster and to a higher extent than vesicles of PC and SM. As in the case of PC/SM mixtures, permeabilization was optimal when the molar ratio of PA/SM was ~1. The preference for membranes containing PA was confirmed by inhibition experiments in which the hemolytic activity of St I was diminished by pre-incubation with vesicles of different composition. The inclusion of even small proportions of PA into PC/SM LUVs led to a marked increase in calcein release caused by both St I and St II, reaching maximal effect at ~5 mol % of PA. Inclusion of other negatively charged lipids (phosphatidylserine (PS), phosphatidylglycerol (PG), phosphatidylinositol (PI), or cardiolipin (CL)), all at 5 mol %, also elicited an increase in calcein release, the potency being in the order CL approximately PA > PG approximately PI approximately PS. However, some boosting effect was also obtained, including the zwitterionic lipid phosphatidylethanolamine (PE) or even, albeit to a lesser extent, the positively charged lipid stearylamine (SA). This indicated that the effect was not mediated by electrostatic interactions between the cytolysin and the negative surface of the vesicles. In fact, increasing the ionic strength of the medium had only a small inhibitory effect on the interaction, but this was actually larger with uncharged vesicles than with negatively charged vesicles. A study of the fluidity of the different vesicles, probed by the environment-sensitive fluorescent dye diphenylhexatriene (DPH), showed that toxin activity was also not correlated to the average membrane fluidity. It is suggested that the insertion of the toxin channel could imply the formation in the bilayer of a nonlamellar structure, a toroidal lipid pore. In this case, the presence of lipids favoring a nonlamellar phase, in particular PA and CL, strong inducers of negative curvature in the bilayer, could help in the formation of the pore. This possibility is confirmed by the fact that the formation of toxin pores strongly promotes the rate of transbilayer movement of lipid molecules, which indicates local disruption of the lamellar structure. PMID:11371451

Valcarcel, C A; Dalla Serra, M; Potrich, C; Bernhart, I; Tejuca, M; Martinez, D; Pazos, F; Lanio, M E; Menestrina, G

2001-06-01

186

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

PubMed Central

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.

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

2014-01-01

187

CgNa, a type I toxin from the giant Caribbean sea anemone Condylactis gigantea shows structural similarities to both type I and II toxins, as well as distinctive structural and functional properties(1).  

PubMed

CgNa (Condylactis gigantea neurotoxin) is a 47-amino-acid- residue toxin from the giant Caribbean sea anemone Condylactis gigantea. The structure of CgNa, which was solved by 1H-NMR spectroscopy, is somewhat atypical and displays significant homology with both type I and II anemone toxins. CgNa also displays a considerable number of exceptions to the canonical structural elements that are thought to be essential for the activity of this group of toxins. Furthermore, unique residues in CgNa define a characteristic structure with strong negatively charged surface patches. These patches disrupt a surface-exposed cluster of hydrophobic residues present in all anemone-derived toxins described to date. A thorough characterization by patch-clamp analysis using rat DRG (dorsal root ganglion) neurons indicated that CgNa preferentially binds to TTX-S (tetrodotoxin-sensitive) voltage-gated sodium channels in the resting state. This association increased the inactivation time constant and the rate of recovery from inactivation, inducing a significant shift in the steady state of inactivation curve to the left. The specific structural features of CgNa may explain its weaker inhibitory capacity when compared with the other type I and II anemone toxins. PMID:17506725

Salceda, Emilio; Pérez-Castells, Javier; López-Méndez, Blanca; Garateix, Anoland; Salazar, Hector; López, Omar; Aneiros, Abel; Ständker, Ludger; Béress, Lászlo; Forssmann, Wolf-Georg; Soto, Enrique; Jiménez-Barbero, Jesús; Giménez-Gallego, Guillermo

2007-08-15

188

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

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

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

1989-01-01

189

Rho participates in chemoreceptor-induced changes in morphology to hair bundle mechanoreceptors of the sea anemone, Nematostella vectensis.  

PubMed

Adjustable hair bundle mechanoreceptors located on anemone tentacles detect movements of nearby, swimming prey. The hair bundles are formed by numerous actin-based stereocilia that converge onto a single, central kinocilium. Interestingly, morphological and functional changes to the hair bundles are induced by activating chemoreceptors that bind prey-derived N-acetylated sugars and proline, respectively. Morphological changes to the hair bundles involve alterations to the actin cytoskeleton of stereocilia. A pharmacological activation of Rho induces hair bundles to elongate to lengths comparable to those normally induced by exposure to N-acetylneuraminic acid (NANA) and prevents shortening of hair bundles normally induced by proline. Rho inhibition prevents NANA-induced elongation, but does not prevent proline-induced shortening of hair bundles. Western blots feature a band similar in mass to that predicted for a Rho homolog in the genome of Nematostella. Immunocytochemistry localizes Rho in stereocilia of the hair bundle. Anemone hair bundles arise from multicellular complexes. Data from experiments using heptanol, a gap junction uncoupler, indicate that cell-cell communication is required in order for activated chemoreceptors to induce morphological changes to the hair bundles. PMID:23474255

Allaire, Kathryn M; Watson, Glen M

2013-06-01

190

A new species of sea anemone ( Saccactis coliumensis n. sp.) living under hypoxic conditions on the central Chilean shelf  

NASA Astrophysics Data System (ADS)

The new species Saccactis coliumensis is described with an emendation of genus Saccactis lager, 1911 (family Actiniidae). The taxonomic relations of the genus are discussed giving additional information on Isoulactis chilensis Carlgren, 1959 and Isocradactis magna sensu Carlgren, 1924. The terms “verrucae”, “vesicles” and “acrorhagi” are discussed and taxonomically valuated. The anemone S. coliumensis lives in eutrophicated sediments on the central Chilean shelf that is at least temporarily under the impact of deoxygenated waters from the Peru-Chile-Subsurface-Current. The most conspicuous features of the new species (the ruff of delicate, gill-like vesicles beneath the tentacles and its thick pedal disc ectoderm with small, fragile spirocysts and cilia-like structures) may be considered adaptive in this peculiar habitat.

Riemann-Zürneck, Karin; Gallardo, Victor A.

1990-09-01

191

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

PubMed Central

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.

Towanda, Trisha; Thuesen, Erik V.

2012-01-01

192

Nutrients, Signals, and Photosynthate Release by Symbiotic Algae (The Impact of Taurine on the Dinoflagellate Alga Symbiodinium from the Sea Anemone Aiptasia pulchella).  

PubMed Central

Exogenous concentrations of 10 [mu]M to 1 mM of the nonprotein amino acid taurine stimulated photosynthate release from the dinoflagellate alga Symbiodinium, which had been freshly isolated from the sea anemone Aiptasia pulchella. Photosynthate release, as induced by taurine and animal extract, was metabolically equivalent at both concentrations in that they (a) stimulated photosynthate release to the same extent and (b) induced the selective release of photosynthetically derived organic acids. A complex mixture of amino acids at 75 mM also promoted photosynthate release, but the release rate was reduced by 34% after the omission of taurine (3 mM) from the mixture, suggesting that much of the effect of amino acids was largely attributable to taurine. Exogenous 14C-labeled taurine was taken up by the cells, and more than 95% of the internalized 14C was recovered as taurine, indicating that taurine-induced photosynthate release was not dependent on taurine metabolism. Both taurine uptake and taurine-induced photosynthate release by Symbiodinium exhibited saturation kinetics, but with significantly different Km values of 68 and 21 [mu]M, respectively. The difference in Km values is compatible with the hypothesis that Symbiodinium has a taurine signal transducer that is responsible for photosynthate release and is distinct from the taurine transporter.

Wang, J. T.; Douglas, A. E.

1997-01-01

193

A Protein Toxin from the Sea Anemone Phyllodiscus semoni Targets the Kidney and Causes a Severe Renal Injury with Predominant Glomerular Endothelial Damage  

PubMed Central

Envenomation by the sea anemone Phyllodiscus semoni causes fulminant dermatitis and, rarely, acute renal failure in humans. Here, we investigated whether the venom extracted from the nematocysts (PsTX-T) was nephrotoxic when administered intravenously in rats and whether PsTX-T induced activation of the complement system. Although small dose of PsTX-T induced acute tubular necrosis in rats resembling pathology seen in patients, kidneys displayed glomerular injury with glomerular endothelial damage, thrombus formation, mesangiolysis, and partial rupture of glomerular basement membrane, accompanied by severe tubular necrosis at 24 hours after administration of 0.03 mg of PsTX-T per animal, similar to the glomerular findings typical of severe hemolytic uremic syndrome. The early stage injury was accompanied by specific PsTX-T binding, massive complement C3b, and membrane attack complex deposition in glomeruli in the regions of injury and decreased glomerular expression of complement regulators. A pathogenic role for complement was confirmed by demonstrating that systemic complement inhibition reduced renal injury. The isolated nephrotoxic component, a 115-kd protein toxin (PsTX-115), was shown to cause identical renal pathology. The demonstration that PsTX-T and PsTX-115 were highly nephrotoxic acting via induction of complement activation suggests that inhibition of complement might be used to prevent acute renal damage following envenomation by P. semoni.

Mizuno, Masashi; Nozaki, Masatoshi; Morine, Nobuya; Suzuki, Norihiko; Nishikawa, Kazuhiro; Morgan, B. Paul; Matsuo, Seiichi

2007-01-01

194

Effects of a toxin from the mucus of the Caribbean sea anemone (Bunodosoma granulifera) on the ionic currents of single ventricular mammalian cardiomyocytes.  

PubMed

The effects were studied of a toxin (Bainh) isolated from the secretion of the Caribbean sea anemone Bunodosoma granulifera on electrical and mechanical activities of rat ventricular muscle. The effects on the ionic currents of single rat and dog ventricular cardiomyocytes were studied using the whole-cell recording patch-clamp technique. In the concentration range from 1 to 10 mg/ml, Bainh increased the force of contraction and induced an increase in action potential duration of ventricular multicellular preparations. In single cardiomyocytes, at concentrations up to 10 mg/ml Bainh showed no significant effects on the sodium current. However, at 0.5-1 mg/ml it increased the L-type Ca current (ICaL) by 25-50%. This increase in ICaL was not voltage dependent and was reversible after washout. The transient outward current was not significantly affected by Bainh (1-10 mg/ml). In this concentration range, Bainh markedly (approximately 75%) increased the inward-going rectifier current, IKI. This effect that was not voltage dependent and was fully reversible upon returning to control solution. It is suggested that these effects on ionic currents could explain the positive inotropic action of Bainh on cardiac multicellular preparations. PMID:9481812

Salinas, E M; Cebada, J; Valdés, A; Garateix, A; Aneiros, A; Alvarez, J L

1997-12-01

195

The sea anemone actinoporin (Arg-Gly-Asp) conserved motif is involved in maintaining the competent oligomerization state of these pore-forming toxins.  

PubMed

Sea anemone actinoporins constitute an optimum model to investigate mechanisms of membrane pore formation. All actinoporins of known structure show a general fold of a ?-sandwich motif flanked by two ?-helices. The crucial structure for pore formation seems to be the helix located at the N-terminal end. The role of several other protein regions in membrane attachment is also well established. However, not much is known about the protein residues involved in the oligomerization required for pore formation. Previous detailed analysis of the soluble three-dimensional structures of different wild-type and mutant actinoporins from Stychodactyla helianthus suggested residues which could be involved in this oligomerization. One of these stretches contains a conserved sequence compatible with an integrin-binding RGD motif. The results presented now deal with mutants affecting this motif in the well-characterized actinoporin sticholysin II. Small modifications along this three-residue sequence had profound effects on its solubility. Just a single methyl group yielded an RAD mutant version with a highly diminished haemolytic activity and altered oligomerization behaviour. The results obtained are discussed in terms of a key role for the RGD motif in maintaining the actinoporins' pore-competent state of protein oligomerization. PMID:24418371

García-Linares, Sara; Richmond, Ryan; García-Mayoral, María F; Bustamante, Noemí; Bruix, Marta; Gavilanes, José G; Martínez-Del-Pozo, Alvaro

2014-03-01

196

Cyclisation Increases the Stability of the Sea Anemone Peptide APETx2 but Decreases Its Activity at Acid-Sensing Ion Channel 3  

PubMed Central

APETx2 is a peptide isolated from the sea anemone Anthopleura elegantissima. It is the most potent and selective inhibitor of acid-sensing ion channel 3 (ASIC3) and it is currently in preclinical studies as a novel analgesic for the treatment of chronic inflammatory pain. As a peptide it faces many challenges in the drug development process, including the potential lack of stability often associated with therapeutic peptides. In this study we determined the susceptibility of wild-type APETx2 to trypsin and pepsin and tested the applicability of backbone cyclisation as a strategy to improve its resistance to enzymatic degradation. Cyclisation with either a six-, seven- or eight-residue linker vastly improved the protease resistance of APETx2 but substantially decreased its potency against ASIC3. This suggests that either the N- or C-terminus of APETx2 is involved in its interaction with the channel, which we confirmed by making N- and C-terminal truncations. Truncation of either terminus, but especially the N-terminus, has detrimental effects on the ability of APETx2 to inhibit ASIC3. The current work indicates that cyclisation is unlikely to be a suitable strategy for stabilising APETx2, unless linkers can be engineered that do not interfere with binding to ASIC3.

Jensen, Jonas E.; Mobli, Mehdi; Brust, Andreas; Alewood, Paul F.; King, Glenn F.; Rash, Lachlan D.

2012-01-01

197

Generation and analysis of transcriptomic resources for a model system on the rise: the sea anemone Aiptasia pallida and its dinoflagellate endosymbiont  

PubMed Central

Background The most diverse marine ecosystems, coral reefs, depend upon a functional symbiosis between cnidarian hosts and unicellular dinoflagellate algae. The molecular mechanisms underlying the establishment, maintenance, and breakdown of the symbiotic partnership are, however, not well understood. Efforts to dissect these questions have been slow, as corals are notoriously difficult to work with. In order to expedite this field of research, we generated and analyzed a collection of expressed sequence tags (ESTs) from the sea anemone Aiptasia pallida and its dinoflagellate symbiont (Symbiodinium sp.), a system that is gaining popularity as a model to study cellular, molecular, and genomic questions related to cnidarian-dinoflagellate symbioses. Results A set of 4,925 unique sequences (UniSeqs) comprising 1,427 clusters of 2 or more ESTs (contigs) and 3,498 unclustered ESTs (singletons) was generated by analyzing 10,285 high-quality ESTs from a mixed host/symbiont cDNA library. Using a BLAST-based approach to predict which unique sequences derived from the host versus symbiont genomes, we found that the contribution of the symbiont genome to the transcriptome was surprisingly small (1.6–6.4%). This may reflect low levels of gene expression in the symbionts, low coverage of alveolate genes in the sequence databases, a small number of symbiont cells relative to the total cellular content of the anemones, or failure to adequately lyse symbiont cells. Furthermore, we were able to identify groups of genes that are known or likely to play a role in cnidarian-dinoflagellate symbioses, including oxidative stress pathways that emerged as a prominent biological feature of this transcriptome. All ESTs and UniSeqs along with annotation results and other tools have been made accessible through the implementation of a publicly accessible database named AiptasiaBase. Conclusion We have established the first large-scale transcriptomic resource for Aiptasia pallida and its dinoflagellate symbiont. These data provide researchers with tools to study questions related to cnidarian-dinoflagellate symbioses on a molecular, cellular, and genomic level. This groundwork represents a crucial step towards the establishment of a tractable model system that can be utilized to better understand cnidarian-dinoflagellate symbioses. With the advent of next-generation sequencing methods, the transcriptomic inventory of A. pallida and its symbiont, and thus the extent of AiptasiaBase, should expand dramatically in the near future.

Sunagawa, Shinichi; Wilson, Emily C; Thaler, Michael; Smith, Marc L; Caruso, Carlo; Pringle, John R; Weis, Virginia M; Medina, Monica; Schwarz, Jodi A

2009-01-01

198

Seasonal changes in the biochemical composition and oxygen consumption of the sea anemone Actinia equina as related to body size and shore level  

Microsoft Academic Search

Seasonal changes of respiratory metabolism and biochemical composition were studied in Actinia equina L. (Cnidaria: Anthozoa) collected in 1982 and 1983 from two shore locations in Spain. Changes of metabolic activity follow closely those of biochemical constituents, particularly carbohydrates and lipids, showing maxima in late fall and spring. Weight dependence, established according to the exponential equation y=a xb (x=weight), results

M. M. Ortega; J. M. Lopez de Pariza; E. Navarro

1988-01-01

199

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

PubMed

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

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

2014-08-01

200

Molecular determinants of high affinity binding of alpha-scorpion toxin and sea anemone toxin in the S3-S4 extracellular loop in domain IV of the Na+ channel alpha subunit.  

PubMed

alpha-Scorpion toxins and sea anemone toxins bind to a common extracellular site on the Na+ channel and inhibit fast inactivation. Basic amino acids of the toxins and domains I and IV of the Na+ channel alpha subunit have been previously implicated in toxin binding. To identify acidic residues required for toxin binding, extracellular acidic amino acids in domains I and IV of the type IIa Na+ channel alpha subunit were converted to neutral or basic amino acids using site-directed mutagenesis, and altered channels were transiently expressed in tsA-201 cells and tested for 125I-alpha-scorpion toxin binding. Conversion of Glu1613 at the extracellular end of transmembrane segment IVS3 to Arg or His blocked measurable alpha-scorpion toxin binding, but did not affect the level of expression or saxitoxin binding affinity. Conversion of individual residues in the IVS3-S4 extracellular loop to differently charged residues or to Ala identified seven additional residues whose mutation caused significant effects on binding of alpha-scorpion toxin or sea anemone toxin. Moreover, chimeric Na+ channels in which amino acid residues at the extracellular end of segment IVS3 of the alpha subunit of cardiac Na+ channels were substituted into the type IIa channel sequence had reduced affinity for alpha-scorpion toxin characteristic of cardiac Na+ channels. Electrophysiological analysis showed that E1613R has 62- and 82-fold lower affinities for alpha-scorpion and sea anemone toxins, respectively. Dissociation of alpha-scorpion toxin is substantially accelerated at all potentials compared to wild-type channels. alpha-Scorpion toxin binding to wild type and E1613R had similar voltage dependence, which was slightly more positive and steeper than the voltage dependence of steady-state inactivation. These results indicate that nonidentical amino acids of the IVS3-S4 loop participate in alpha-scorpion toxin and sea anemone toxin binding to overlapping sites and that neighboring amino acid residues in the IVS3 segment contribute to the difference in alpha-scorpion toxin binding affinity between cardiac and neuronal Na+ channels. The results also support the hypothesis that this region of the Na+ channel is important for coupling channel activation to fast inactivation. PMID:8663157

Rogers, J C; Qu, Y; Tanada, T N; Scheuer, T; Catterall, W A

1996-07-01

201

Phyla- and Subtype-Selectivity of CgNa, a Na+ Channel Toxin from the Venom of the Giant Caribbean Sea Anemone Condylactis Gigantea  

PubMed Central

Because of their prominent role in electro-excitability, voltage-gated sodium (NaV) channels have become the foremost important target of animal toxins. These toxins have developed the ability to discriminate between closely related NaV subtypes, making them powerful tools to study NaV channel function and structure. CgNa is a 47-amino acid residue type I toxin isolated from the venom of the Giant Caribbean Sea Anemone Condylactis gigantea. Previous studies showed that this toxin slows the fast inactivation of tetrodotoxin-sensitive NaV currents in rat dorsal root ganglion neurons. To illuminate the underlying NaV subtype-selectivity pattern, we have assayed the effects of CgNa on a broad range of mammalian isoforms (NaV1.2–NaV1.8) expressed in Xenopus oocytes. This study demonstrates that CgNa selectively slows the fast inactivation of rNaV1.3/?1, mNaV1.6/?1 and, to a lesser extent, hNaV1.5/?1, while the other mammalian isoforms remain unaffected. Importantly, CgNa was also examined on the insect sodium channel DmNaV1/tipE, revealing a clear phyla-selectivity in the efficacious actions of the toxin. CgNa strongly inhibits the inactivation of the insect NaV channel, resulting in a dramatic increase in peak current amplitude and complete removal of fast and steady-state inactivation. Together with the previously determined solution structure, the subtype-selective effects revealed in this study make of CgNa an interesting pharmacological probe to investigate the functional role of specific NaV channel subtypes. Moreover, further structural studies could provide important information on the molecular mechanism of NaV channel inactivation.

Billen, Bert; Debaveye, Sarah; Beress, Laszlo; Tytgat, Jan

2010-01-01

202

Phyla- and Subtype-Selectivity of CgNa, a Na Channel Toxin from the Venom of the Giant Caribbean Sea Anemone Condylactis Gigantea.  

PubMed

Because of their prominent role in electro-excitability, voltage-gated sodium (Na(V)) channels have become the foremost important target of animal toxins. These toxins have developed the ability to discriminate between closely related Na(V) subtypes, making them powerful tools to study Na(V) channel function and structure. CgNa is a 47-amino acid residue type I toxin isolated from the venom of the Giant Caribbean Sea Anemone Condylactis gigantea. Previous studies showed that this toxin slows the fast inactivation of tetrodotoxin-sensitive Na(V) currents in rat dorsal root ganglion neurons. To illuminate the underlying Na(V) subtype-selectivity pattern, we have assayed the effects of CgNa on a broad range of mammalian isoforms (Na(V)1.2-Na(V)1.8) expressed in Xenopus oocytes. This study demonstrates that CgNa selectively slows the fast inactivation of rNa(V)1.3/?(1), mNa(V)1.6/?(1) and, to a lesser extent, hNa(V)1.5/?(1), while the other mammalian isoforms remain unaffected. Importantly, CgNa was also examined on the insect sodium channel DmNa(V)1/tipE, revealing a clear phyla-selectivity in the efficacious actions of the toxin. CgNa strongly inhibits the inactivation of the insect Na(V) channel, resulting in a dramatic increase in peak current amplitude and complete removal of fast and steady-state inactivation. Together with the previously determined solution structure, the subtype-selective effects revealed in this study make of CgNa an interesting pharmacological probe to investigate the functional role of specific Na(V) channel subtypes. Moreover, further structural studies could provide important information on the molecular mechanism of Na(V) channel inactivation. PMID:21833172

Billen, Bert; Debaveye, Sarah; Béress, Lászlo; Garateix, Anoland; Tytgat, Jan

2010-01-01

203

Characterization and localization of mitochondrial DNA-encoded tRNAs and nuclear DNA-encoded tRNAs in the sea anemone Metridium senile.  

PubMed

The mitochondrial (mt) genome of the sea anemone Metridium senile contains genes for only two transfer RNAs (tRNAs), tRNAf-Met and tRNATrp. Experiments were conducted to seek evidence for the occurrence of functional tRNAs corresponding to these genes and for the participation of nuclear DNA-encoded tRNAs in mt-protein synthesis. RNA sequences corresponding to the two mt-tRNA genes were located in mitochondria and it was shown that 3'-CC (and possibly A, but no other nucleotide) is added post-transcriptionally to the 3' end of at least 50 % of mt-tRNAf-Met molecules and to a small fraction of the mt-tRNATrp molecules. Using specific oligonucleotide primers based on expected nuclear DNA-encoded tRNAs in a series of RACE experiments, we located the nuclear genes for tRNAGln, tRNAIle, tRNAi-Met, tRNAVal and tRNAThr. Data from Northern blot analyses indicated that mtDNA-encoded tRNAf-Met is limited to mitochondria but that nuclear DNA-encoded tRNAVal and tRNAi-Met are present in the cytoplasm and in mitochondria. These data provide direct evidence that in M. senile, mature, functional tRNAs are transcribed from the mtDNA-encoded tRNAf-Met and tRNATrp genes, and are consistent with the interpretation that both nuclear DNA-encoded tRNAVal and tRNAi-Met are utilized in mitochondrial and cytosolic protein synthesis. PMID:23801360

Beagley, C Timothy; Wolstenholme, David R

2013-08-01

204

Characteristics of Anemone Active Regions Appearing in Coronal Holes Observed with the Yohkoh Soft X-Ray Telescope  

NASA Astrophysics Data System (ADS)

Coronal structure of active regions appearing in coronal holes is studied, using data that were obtained with the Soft X-Ray Telescope (SXT) aboard Yohkoh between 1991 November and 1993 March. The following characteristics are found. Many of the active regions (ARs) appearing in coronal holes show a structure that looks like a sea anemone. Such active regions are called anemone ARs. About one-fourth of all active regions that were observed with SXT from their births showed the anemone structure. For almost all the anemone ARs, the order of the magnetic polarities is consistent with the Hale-Nicholson polarity law. These anemone ARs also showed, to a greater or lesser extent, an east-west asymmetry in the X-ray intensity distribution, such that the following (eastern) part of the AR was brighter than its preceding (western) part. This, as well as the anemone shape itself, is consistent with the magnetic polarity distribution around the anemone ARs. These observations also suggest that an active region appearing in coronal holes has a simpler (less sheared) and more preceding-spot-dominant magnetic structure than those appearing in other regions.

Asai, Ayumi; Shibata, Kazunari; Hara, Hirohisa; Nitta, Nariaki V.

2008-02-01

205

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)

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.

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

2013-02-01

206

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

Microsoft Academic Search

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

Hironobu Fukami; Nancy Knowlton

2005-01-01

207

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

PubMed Central

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.

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

2012-01-01

208

High In Situ Repeatability of Behaviour Indicates Animal Personality in the Beadlet Anemone Actinia equina (Cnidaria)  

Microsoft Academic Search

‘Animal personality’ means that individuals differ from one another in either single behaviours or suites of related behaviours in a way that is consistent over time. It is usually assumed that such consistent individual differences in behaviour are driven by variation in how individuals respond to information about their environment, rather than by differences in external factors such as variation

Mark Briffa; Julie Greenaway

2011-01-01

209

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

NASA Astrophysics Data System (ADS)

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 3960m 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.

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

2013-12-01

210

Biochemical-genetic and ecological evidence that red\\/brown individuals of the anemone Actinia equina comprise two morphs in Britain  

Microsoft Academic Search

A study of the sea anemone Actinia equina L. displaying red to brown column coloration was conducted on British shores in 1981 and 1982 in order to assess the ecological significance of discontinuous variation in pedal disc colour. Two ecologically distinct morphs have been revealed. One is characterised by having a red\\/pink pedal disc, and by being homozygous slow or

D. L. J. Quicke; A. M. Donoghue; R. C. Brace

1983-01-01

211

Global population genetic structure of the starlet anemone Nematostella vectensis : multiple introductions and implications for conservation policy  

Microsoft Academic Search

Distinguishing natural versus anthropogenic dispersal of organisms is essential for determining the native range of a species\\u000a and implementing an effective conservation strategy. For cryptogenic species with limited historical records, molecular data\\u000a can help to identify introductions. Nematostella vectensis is a small, burrowing estuarine sea anemone found in tidally restricted salt marsh pools. This species’ current distribution\\u000a extends over three

Adam M. Reitzel; John A. Darling; James C. Sullivan; John R. Finnerty

2008-01-01

212

AdE-1, a new inotropic Na(+) channel toxin from Aiptasia diaphana, is similar to, yet distinct from, known anemone Na(+) channel toxins.  

PubMed

Heart failure is one of the most prevalent causes of death in the western world. Sea anemone contains a myriad of short peptide neurotoxins affecting many pharmacological targets, several of which possess cardiotonic activity. In the present study we describe the isolation and characterization of AdE-1 (ion channel modifier), a novel cardiotonic peptide from the sea anemone Aiptasia diaphana, which differs from other cnidarian toxins. Although AdE-1 has the same cysteine residue arrangement as sea anemone type 1 and 2 Na(+) channel toxins, its sequence contains many substitutions in conserved and essential sites and its overall homology to other toxins identified to date is low (<36%). Physiologically, AdE-1 increases the amplitude of cardiomyocyte contraction and slows the late phase of the twitch relaxation velocity with no induction of spontaneous twitching. It increases action potential duration of cardiomyocytes with no effect on its threshold and on the cell's resting potential. Similar to other sea anemone Na(+) channel toxins such as Av2 (Anemonia viridis toxin II), AdE-1 markedly inhibits Na(+) current inactivation with no significant effect on current activation, suggesting a similar mechanism of action. However, its effects on twitch relaxation velocity, action potential amplitude and on the time to peak suggest that this novel toxin affects cardiomyocyte function via a more complex mechanism. Additionally, Av2's characteristic delayed and early after-depolarizations were not observed. Despite its structural differences, AdE-1 physiologic effectiveness is comparable with Av2 with a similar ED(50) value to blowfly larvae. This finding raises questions regarding the extent of the universality of structure-function in sea anemone Na(+) channel toxins. PMID:23356888

Nesher, Nir; Shapira, Eli; Sher, Daniel; Moran, Yehu; Tsveyer, Liora; Turchetti-Maia, Ana Luiza; Horowitz, Michal; Hochner, Binyamin; Zlotkin, Eliahu

2013-04-01

213

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

PubMed

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

Grajales, Alejandro; Rodríguez, Estefanía

2014-01-01

214

Size-dependent dominance hierarchy in the anemone Actinia equina  

Microsoft Academic Search

THERE are many examples of aggression among anthozoan coelenterates: corals show interspecific interaction in which ranking may be obvious1, and inter-clonal aggression occurs in the anemone Anthopleura elegantissima2. Aggressive behaviour is also exhibited by some solitary anemones, such as Actinia equina L. Both these species possess special structures bearing batteries of nematocysts, the acrorhagi which are used solely for offence3.

R. C. Brace; Janis Pavey

1978-01-01

215

Searching for a toxic key to unlock the mystery of anemonefish and anemone symbiosis.  

PubMed

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

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

2014-01-01

216

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

PubMed Central

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.

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

2014-01-01

217

Comprehensive EST analysis of the symbiotic sea anemone, Anemonia viridis  

Microsoft Academic Search

BACKGROUND: Coral reef ecosystems are renowned for their diversity and beauty. Their immense ecological success is due to a symbiotic association between cnidarian hosts and unicellular dinoflagellate algae, known as zooxanthellae. These algae are photosynthetic and the cnidarian-zooxanthellae association is based on nutritional exchanges. Maintenance of such an intimate cellular partnership involves many crosstalks between the partners. To better characterize

Cécile Sabourault; Philippe Ganot; Emeline Deleury; Denis Allemand; Paola Furla

2009-01-01

218

Amino acid synthesis in the symbiotic sea anemone Aiptasia pulchella  

Microsoft Academic Search

Symbiotic Aiptasia pulchella and freshly isolated zooxanthellae were incubated in NaH14CO3 and NH4Cl for 1 to 240?min, and samples were analysed by reverse-phase high-performance liquid chromatography (HPLC) and an online\\u000a radiochemical detector. NH4\\u000a \\u000a + was first assimilated into 14C-glutamate and 14C-glutamine in the zooxanthellae residing in A. pulchella. The specific activities (dpm?nmol?1) of 14C-glutamate and 14C-glutamine in vivo, were far

R. Swanson; O. Hoegh-Guldberg

1998-01-01

219

Experimental habituation of aggression in the sea anemone Actinia equina  

Microsoft Academic Search

Behavioural plasticity in Actinia equina (L.) was examined in experimental contests using a range of pedal disc colour phenotypes, which characterize 3 known, ecologically distinct morphs. With repeated pairing of individuals in auto-phenotypic encounters, habituation was easily induced in the 2 mid-shore morphs, but was not obvious in the less aggressive, low-shore form. Subsequent pairing with a different partner revealed

R. C. Brace; S.-J. Santer

1991-01-01

220

Mechanisms of tentacle morphogenesis in the sea anemone Nematostella vectensis.  

PubMed

Evolution of the capacity to form secondary outgrowths from the principal embryonic axes was a crucial innovation that potentiated the diversification of animal body plans. Precisely how such outgrowths develop in early-branching metazoan species remains poorly understood. Here we demonstrate that three fundamental processes contribute to embryonic tentacle development in the cnidarian Nematostella vectensis. First, a pseudostratified ectodermal placode forms at the oral pole of developing larvae and is transcriptionally patterned into four tentacle buds. Subsequently, Notch signaling-dependent changes in apicobasal epithelial thickness drive elongation of these primordia. In parallel, oriented cell rearrangements revealed by clonal analysis correlate with shaping of the elongating tentacles. Taken together, our results define the mechanism of embryonic appendage development in an early-branching metazoan, and thereby provide a novel foundation for understanding the diversification of body plans during animal evolution. PMID:23633514

Fritz, Ashleigh E; Ikmi, Aissam; Seidel, Christopher; Paulson, Ariel; Gibson, Matthew C

2013-05-01

221

Slideshow: Deep-sea Spiders Have a Snack  

NSDL National Science Digital Library

Three thousand meters below the ocean's surface, a remotely operated vehicle has captured never-before seen images of deep-sea spiders feeding in their natural habitat. These sluggish, long-legged spiders, which occupy a distinct class of arthropods from land spiders, survive on sea anemones in a submarine canyon off the Central California coast.

Janelle Weaver (AAAS;)

2009-12-24

222

The form and function of Cnidarian spirocysts  

Microsoft Academic Search

The commonest intracellular organelle characteristic of the Phylum Cnidaria or Coelenterata (Subclass Zoantharia) is the spirocyst. Based on scanning and transmission electron microscopy of the tentacles of sea anemones and corals, it appears that the tip of the spirocyst is either exposed to the environment or covered by a thin plasma membrane and often has a pebbled or knobby appearance.

Richard N. Mariscal; Charles H. Bigger; Richard B. McLean

1976-01-01

223

Chromospheric anemone jets as evidence of ubiquitous reconnection.  

PubMed

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

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

224

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

NASA Astrophysics Data System (ADS)

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.

Fukami, Hironobu; Knowlton, Nancy

2005-11-01

225

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

PubMed Central

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.

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

2013-01-01

226

Benthic Community Composition and Seabed Characteristics of a Chukchi Sea Pockmark  

NASA Astrophysics Data System (ADS)

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.

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

2005-12-01

227

DYNAMICS OF SOMATIC CELL-LINEAGE COMPETITION IN CHIMERAS OF Hydractinia symbiolongicarpus (CNIDARIA: HYDROZOA) Dinámica de competencia entre líneas celulares somáticas en quimeras de Hydractinia symbiolongicarpus (Cnidaria: Hydrozoa)  

Microsoft Academic Search

Sessile colonial invertebrates often fuse with conspecifics to form chimeras. Chimerism represents an unequivocal instance of within-individual selection where genetically different cell-lineages compete for representation in the somatic and gametic pools. We analyzed temporal and spatial variations in somatic cell-lineage composition of laboratory-established chimeras of the hydroid Hydractinia symbiolongicarpus (Cnidaria: Hydrozoa). Using three clones with different allotypic specificities (i.e., two

RYAN S. SCHWARZ; LUIS F. CADAVID

228

Evolution of the anemone AR NOAA 10798 and the related geo-effective flares and CMEs  

NASA Astrophysics Data System (ADS)

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 sea anemone like configuration. H? 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.

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

2009-02-01

229

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...

230

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

PubMed

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

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

2013-01-01

231

Ecological speciation in anemone-associated snapping shrimps (Alpheus armatus species complex).  

PubMed

Divergent natural selection driven by competition for limited resources can promote speciation, even in the presence of gene flow. Reproductive isolation is more likely to result from divergent selection when the partitioned resource is closely linked to mating. Obligate symbiosis and host fidelity (mating on or near the host) can provide this link, creating ideal conditions for speciation in the absence of physical barriers to dispersal. Symbiotic organisms often experience competition for hosts, and host fidelity ensures that divergent selection for a specific host or host habitat can lead to speciation and strengthen pre-existing reproductive barriers. Here, we present evidence that diversification of a sympatric species complex occurred despite the potential for gene flow and that partitioning of host resources (both by species and by host habitat) has contributed to this diversification. Four species of snapping shrimps (Alpheus armatus, A. immaculatus, A. polystictus and A. roquensis) are distributed mainly sympatrically in the Caribbean, while the fifth species (A. rudolphi) is restricted to Brazil. All five species are obligate commensals of sea anemones with a high degree of fidelity and ecological specificity for host species and habitat. We analysed sequence data from 10 nuclear genes and the mitochondrial COI gene in 11-16 individuals from each of the Caribbean taxa and from the only available specimen of the Brazilian taxon. Phylogenetic analyses support morphology-based species assignments and a well-supported Caribbean clade. The Brazilian A. rudolphi is recovered as an outgroup to the Caribbean taxa. Isolation-migration coalescent analysis provides evidence for historical gene flow among sympatric sister species. Our data suggest that both selection for a novel host and selection for host microhabitat may have promoted diversification of this complex despite gene flow. PMID:23859595

Hurt, C; Silliman, K; Anker, A; Knowlton, N

2013-09-01

232

Phylogenetic analysis with multiple markers indicates repeated loss of the adult medusa stage in Campanulariidae (Hydrozoa, Cnidaria)  

Microsoft Academic Search

The Campanulariidae is a group of leptomedusan hydroids (Hydrozoa, Cnidaria) that exhibit a diverse array of life cycles ranging from species with a free medusa stage to those with a reduced or absent medusa stage. Perhaps the best-known member of the taxon is Obelia which is often used as a textbook model of hydrozoan life history. However, Obelia medusae have

Annette F. Govindarajan; Ferdinando Boero; Kenneth M. Halanych

2006-01-01

233

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

Microsoft Academic Search

Nematogenesis, the production of stinging cells (nematocytes) in Cnidaria, can be considered as a model neurogenic process. Most molecular data concern the freshwater polyp Hydra, in which nematocyte production is scattered throughout the body column ectoderm, the mature cells then migrating to the tentacles. We have characterized tentacular nematogenesis in the Clytia hemisphaerica hydromedusa and found it to be confined

Elsa Denker; Michaël Manuel; Lucas Leclère; Hervé Le Guyader; Nicolas Rabet

2008-01-01

234

A new species of Pseudomacrochiron Reddiah, 1969 (Crustacea: Copepoda: Macrochironidae) associated with scyphistomae of the moon jellyfish Aurelia sp. (Cnidaria: Scyphozoa) off Japan.  

PubMed

A new species of the Macrochironidae Humes & Boxshall, 1996 (Copepoda: Cyclopoida), Pseudomacrochiron aureliae n. sp., is described based on adult specimens extracted from the gastrovacular cavity of the scyphistomae of Aurelia sp. (Cnidaria: Scyphozoa) collected in the Seto Inland Sea and Ise Bay off the coast of Japan. The new species differs from its congeners by having the following combination of characters: a caudal ramus with a length to width ratio of 3.1; an accessory flagellum on caudal setae II, III and VI; three apical setae on the maxillule; only setae I and II on the maxillary basis; two short spines on the female maxilliped claw (endopod); an armature of III, I, 4 on the terminal exopodal segment of leg 3; an armature of I, II, 2 on the terminal endopodal segment of leg 3; an armature of II, I, 4 on the terminal exopodal segment of leg 4; and a short free exopodal segment of leg 5 (length to width ratio of 1.4) armed with a long seta and short spine. P. aureliae n. sp. is the first member of the genus reported from off Japan and from the scyphistomae of its scyphozoan host. PMID:22183922

Tang, Danny; Yasuda, Akira; Yamada, Satoshi; Nagasawa, Kazuya

2012-02-01

235

Biological community and sediment fatty acids associated with the deep-sea whale skeleton at the Torishima Seamount  

Microsoft Academic Search

A whale skeleton was discovered on the flat-topped summit of the Torishima Seamount, 4037 m deep, northwest Pacific Ocean, during a dive by the submersibleShinkai 6500 in 1992. The skeleton was encrusted with mytilid mussels and harbored benthic animals such as galatheid crabs, echinoderms, sea anemones, and unidentifiable tube worms. The whale skeleton was revisited in 1993. Sediment samples were

Takeshi Naganuma; Hideki Wada; Kantaro Fujioka

1996-01-01

236

Similar specificities of symbiont uptake by adults and larvae in an anemone model system for coral biology.  

PubMed

Reef-building corals depend for much of their energy on photosynthesis by symbiotic dinoflagellate algae (genus Symbiodinium) that live within their gastrodermal cells. However, the cellular mechanisms underpinning this ecologically critical symbiosis, including those governing the specificity of symbiont uptake by the host, remain poorly understood, in part because of the difficulties of working with corals in the laboratory. Here, we used the small symbiotic sea anemone Aiptasia as an experimentally tractable model system to analyze the specificity and timing of symbiosis onset in larval and adult animals under controlled laboratory conditions. Using four clonal, axenic Symbiodinium strains, we found no difference in uptake specificity between larvae (even when very young) and adults. Although both compatible and incompatible algal strains were found within the larval guts, only the former appeared to be internalized by gastrodermal cells, and they (but not incompatible algae) proliferated rapidly within the larvae in the absence of detectable exchange with other larvae. Older larvae showed reduced ingestion of both compatible and incompatible algae, and the addition of food failed to promote the uptake of an incompatible algal strain. Thus, Aiptasia adults and larvae appear to have similar mechanisms for discriminating between compatible and incompatible dinoflagellate types prior to phagocytosis by host gastrodermal cells. Whether a particular algal strain is compatible or incompatible appears to be stable during years of axenic culture in the absence of a host. These studies provide a foundation for future analyses of the mechanisms of symbiont-uptake specificity in this emerging model system. PMID:24526722

Hambleton, Elizabeth A; Guse, Annika; Pringle, John R

2014-05-01

237

Numerical Simulations of Chromospheric Anemone Jets Associated with Moving Magnetic Features  

NASA Astrophysics Data System (ADS)

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.

Yang, Liping; He, Jiansen; Peter, Hardi; Tu, Chuanyi; Zhang, Lei; Feng, Xueshang; Zhang, Shaohua

2013-11-01

238

The mitochondrial genome of Acropora tenuis (Cnidaria; Scleractinia) contains a large group I intron and a candidate control region.  

PubMed

The complete nucleotide sequence of the mitochondrial genome of the coral Acropora tenuis has been determined. The 18,338 bp A. tenuis mitochondrial genome contains the standard metazoan complement of 13 protein-coding and two rRNA genes, but only the same two tRNA genes (trnM and trnW) as are present in the mtDNA of the sea anemone, Metridium senile. The A. tenuis nad5 gene is interrupted by a large group I intron which contains ten protein-coding genes and rns; M. senile has an intron at the same position but this contains only two protein-coding genes. Despite the large distance (about 11.5 kb) between the 5?-exon and 3?-exon boundaries, the A. tenuis nad5 gene is functional, as we were able to RT-PCR across the predicted intron splice site using total RNA from A. tenuis. As in M. senile, all of the genes in the A. tenuis mt genome have the same orientation, but their organization is completely different in these two zoantharians: The only common gene boundaries are those at each end of the group I intron and between trnM and rnl. Finally, we provide evidence that the rns-cox3 intergenic region in A. tenuis may correspond to the mitochondrial control region of higher animals. This region contains repetitive elements, and has the potential to form secondary structures of the type characteristic of vertebrate D-loops. Comparisons between a wide range of Acropora species showed that a long hairpin predicted in rns-cox3 is phylogenetically conserved, and allowed the tentative identification of conserved sequence blocks. PMID:12165838

van Oppen, Madeleine J H; Catmull, Julian; McDonald, Brenda J; Hislop, Nikki R; Hagerman, Paul J; Miller, David J

2002-07-01

239

Observations on the feeding behaviour of Paratrichodorus anemones in relation to tobravirus transmission.  

PubMed

Feeding by P. anemones, an efficient vector of tobacco rattle virus (TRV), was investigated by video-enhanced interference light microscopy. Four stages were observed after transfer of individual nematodes, extracted from soil, to Nicotiana tabacum seedling roots in agar: i) acclimatisation; ii) approach and scrutiny; iii) preparation; and iv) feeding. Prior to commencement of stage 'iv' about 4 cells perforated by rapid onchiostyle thrusting remained alive, each having been almost immediately abandoned by the nematode. During the stage iv) approximately 5% of perforated cells remained alive. Feeding on individual cells was similar to that previously reported for Trichodorus similis: cells from which cytoplasm was ingested after a prolonged period of salivation were invariably killed, with adjacent cells being unaffected. During feeding a number of cells perforated but soon afterwards abandoned by P. anemones remained alive, providing an effective pathway for successful transmission of TRV to plants by the nematode. PMID:12425083

Karanastasi, E; Wyss, U; Brown, D

2001-01-01

240

Shared antigenicity between the polar filaments of myxosporeans and other Cnidaria.  

PubMed

Nematocysts containing coiled polar filaments are a distinguishing feature of members of the phylum Cnidaria. As a first step to characterizing the molecular structure of polar filaments, a polyclonal antiserum was raised in rabbits against a cyanogen bromide-resistant protein extract of mature cysts containing spores of Myxobolus pendula. The antiserum reacted only with proteins associated with extruded polar filaments. Western blot and whole-mount immunohistochemical analyses indicated a conservation of polar filament epitopes between M. pendula and 2 related cnidarians, i.e., the anthozoan, Nematostella vectensis, and the hydrozoan, Hydra vulgaris. This conservation of polar filament epitopes lends further support to a shared affinity between Myxozoa and cnidarians. PMID:21348629

Ringuette, Maurice J; Koehler, Anne; Desser, Sherwin S

2011-02-01

241

Isolation and identification of chitin in the black coral Parantipathes larix (Anthozoa: Cnidaria).  

PubMed

Until now, there is a lack of knowledge about the presence of chitin in numerous representatives of corals (Cnidaria). However, investigations concerning the chitin-based skeletal organization in different coral taxa are significant from biochemical, structural, developmental, ecological and evolutionary points of view. In this paper, we present a thorough screening for the presence of chitin within the skeletal formations of a poorly investigated Mediterranean black coral, Parantipathes larix (Esper, 1792), as a typical representative of the Schizopathidae family. Using a wide array variety of techniques ((13)C solid state NMR, Fourier transform infrared (FTIR), Raman, NEXAFS, Morgan-Elson assay and Calcofluor White Staining), we unambiguously show for the first time that chitin is an important component within the skeletal stalks as well as pinnules of this coral. PMID:22546360

Bo, Marzia; Bavestrello, Giorgio; Kurek, Denis; Paasch, Silvia; Brunner, Eike; Born, René; Galli, Roberta; Stelling, Allison L; Sivkov, Viktor N; Petrova, Olga V; Vyalikh, Denis; Kummer, Kurt; Molodtsov, Serguei L; Nowak, Dorota; Nowak, Jakub; Ehrlich, Hermann

2012-01-01

242

Molecular structure and chromosome distribution of three repetitive DNA families in Anemone hortensis L. (Ranunculaceae)  

Microsoft Academic Search

The structure, abundance and location of repetitive DNA sequences on chromosomes can characterize the nature of higher plant\\u000a genomes. Here we report on three new repeat DNA families isolated from Anemone hortensis L.; (i) AhTR1, a family of satellite DNA (stDNA) composed of a 554–561 bp long EcoRV monomer; (ii) AhTR2, a stDNA family composed of a 743 bp long HindIII monomer

Jelena Mlinarec; Mike Chester; Sonja Siljak-Yakovlev; Dražena Papeš; Andrew R. Leitch; Višnja Besendorfer

2009-01-01

243

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

PubMed Central

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.

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

2013-01-01

244

Chromospheric Anemone Jets Observed with Hinode/SOT and Hida Ca II Spectroheliograph  

NASA Astrophysics Data System (ADS)

We present the first simultaneous observations of chromospheric “anemone” jets in active regions with the Ca II H broadband filetergram on the Hinode/SOT and with the Ca II K spetroheliogram on the Domeless Solar Telescope (DST) at the Hida Observatory. During coordinated observation period, 9 chromospheric anemone jets were simultaneously observed with the two instruments. These observations revealed: (1) the jets are generated in the low chromosphere because these cannot be seen in Ca II K3, (2) these jets are associated with mixed polarity regions which are either small emerging flux regions or moving magnetic features, (3) the Ca II K line often show red or blue asymmetry in K2/K1 component; the footpoint of the jets associated with emerging flux regions often show red asymmetry (2-16 km s-1), while the one with moving magnetic features show blue asymmetry (˜5 km s-1). The magnetic cancellations were observed at the footpoint of the jets. The canceling rates are of order of 1016 Mx s-1, and the resulting magnetic energy release rate (1.1-10)×1024 erg s-1, with the total energy release (1-13)×1026 erg for the duration of the magnetic cancellations, ˜130 s. These are comparable to the estimated total energy, ˜1026 erg, in a single chromospheric anemone jet.

Morita, S.; Shibata, K.; Ueno, S.; Ichimoto, K.; Kitai, R.; Otsuji, K.

2012-08-01

245

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

NASA Astrophysics Data System (ADS)

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.

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

2014-01-01

246

Cytotoxicity of the nematocyst venom from the sea anemone Aiptasia mutabilis  

Microsoft Academic Search

Crude extracts of the coelenterate Aiptasia mutabilis (Anthozoa, Aiptasiidae) nematocysts have been tested for their cytotoxicity of Vero and HEp-2 cells monolayers. The results indicate that the nematocyte venom contains one or more toxins with an extremely powerful cytolytic activity. An extract containing the equivalent of as little as 0.6 nematocysts\\/?L is sufficient to induce significant cellular necrosis, and IC50

Angela Marino; Vincenza Valveri; Carmelo Muià; Rosalia Crupi; Gianluca Rizzo; Giovanni Musci; Giuseppa La Spada

2004-01-01

247

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

PubMed Central

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.

2014-01-01

248

Expression of Sea Anemone Equistatin in Potato. Effects of Plant Proteases on Heterologous Protein Production1  

PubMed Central

Plants are increasingly used as production platforms of various heterologous proteins, but rapid protein turnover can seriously limit the steady-state expression level. Little is known about specific plant proteases involved in this process. In an attempt to obtain potato (Solanum tuberosum cv Desirée) plants resistant to Colorado potato beetle (Leptinotarsa decemlineata Say) larvae, the protease inhibitor equistatin was expressed under the control of strong, light-inducible and constitutive promoters and was targeted to the secretory pathway with and without endoplasmic reticulum retention signal. All constructs yielded similar stepwise protein degradation patterns, which considerably reduced the amount of active inhibitor in planta and resulted in insufficient levels for resistance against Colorado potato beetle larvae. Affinity purification of the degradation products and N-terminal sequencing allowed the identification of the amino acid P1-positions (asparagine [Asn]-13, lysine-56, Asn-82, and arginine-151) that were cleaved in planta. The proteases involved in the equistatin degradation were characterized with synthetic substrates and inhibitors. Kininogen domain 3 completely inhibited equistatin degradation in vitro. The results indicate that arginine/lysine-specific and legumain-type Asn-specific cysteine proteases seriously impede the functional accumulation of recombinant equistatin in planta. General strategies to improve the resistance to proteases of heterologous proteins in plants are proposed.

Outchkourov, Nikolay S.; Rogelj, Boris; Strukelj, Borut; Jongsma, Maarten A.

2003-01-01

249

On the expansion-contraction rhythm of the sea anemone, Actinia equina L  

Microsoft Academic Search

Riassunto È stato studiato il ritmo di espansione-contrazione di esemplari diActinia equina L. della zona interoctidale del Mar Tirreno, sottoposti a condizioni differenti di illuminazione e di livello d'acqua. Gli autori ritengono che il ritmo sia direttamente dipendente dall'illuminazione ambientale e dallo stato di copertura o scopertura conseguente alle maree. Una luce di intensità pari a quella lunare non esercita

A. Milia; L. Geppetti

1964-01-01

250

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

SciTech Connect

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.

Arnold Levine

2009-09-14

251

Unexpected complexity of the Wnt gene family in a sea anemone  

Microsoft Academic Search

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

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

2005-01-01

252

Protection of a hermit crab by its symbiotic sea anemone Calliactis tricolor  

Microsoft Academic Search

Zusammenfassung Experimenteller Nachweis, dass Einsiedlerkrebse,Pagurus pollicaris, mit symbiontischer Seeanemone,Calliactis tricolor, anf ihrer Schale vom natürlichen Feind der Krabbe,Calappa flammea, weitgehend gemieden werden.

R. B. McLean; R. N. Mariscal

1973-01-01

253

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

Microsoft Academic Search

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

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

1992-01-01

254

ADAPTATIONS TO ENVIRONMENTAL OXYGEN LEVELS IN INFATJNAL AND EPIFAUNAL SEA ANEMONES  

Microsoft Academic Search

Numerous investigators have shown correhatioius between various physiological properties of aquatic organisms amidthe chuaracteristic levels of oxygemuin which the aninuals are foumud. Older studies omusurvival timuueumuder how oxygen coiuditions gemuerally imudicate that, withimu closely related groups, burrowimug species are more resistamut to oxygen deprivatiomu thamu epifaunal forms (Packard, 1905). Sinuilarly, animals living imufast-moving streanus are less resistant than those living

CLAY SASSAMAN; CHARLOTTE P. MANGUM

1972-01-01

255

The Association between the Hermit Crab Dardanus arrosor (Herbst) and the Sea Anemone Calliactis parasitica (Couch)  

Microsoft Academic Search

The association between Calliactis parasitica and the Mediterranean hermit crab, Dardanus arrosor, has been re-examined. It was confirmed that, unlike the Atlantic crab, Pagurus bernhardus, Dardanus arrosor can display an active behaviour pattern which assists the transfer of Calliactis to its shell. Extensive trials showed, however, a marked tendency for crabs to divide into two groups: 'performers', which show this

D. M. Ross; L. Sutton

1961-01-01

256

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

Microsoft Academic Search

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.

D. J. Ayre

1984-01-01

257

The Response of the Sea Anemone Calliactis parasitica to Shells of the Hermit Crab Pagurus bernhardus  

Microsoft Academic Search

The five stages in the behaviour pattern by which Calliactis parasitica transfers to shells of Buccinum, normally occupied by Pagurus bernhardus, are described. The first of these, the clinging of tentacles to shell, is a trigger for the pattern as a whole; it occurs in Calliactis already settled on glass or plastic, and more consistently, in Calliactis whose pedal disks

D. M. Ross; L. Sutton

1961-01-01

258

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

SciTech Connect

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

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

2010-09-01

259

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

PubMed Central

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.

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

2010-01-01

260

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

USGS Publications Warehouse

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.

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

2011-01-01

261

Seasonal changes in photosynthetic characteristics of Anemone raddeana , a spring-active geophyte, in the temperate region of Japan  

Microsoft Academic Search

Seasonal changes in the photosynthetic characteristics of intact involucral leaves of Anemone raddeana were investigated under laboratory conditions. Net photosynthesis and constant water vapor pressure deficit showed almost the same seasonal trend. They increased rapidly from mid-April immediately after unfolding of the leaves and reached the maximum in late-April, before the maximum expansion of the leaves. They retained the maximum

F. Yoshie; S. Yoshida

1987-01-01

262

A new species of Hormathia (Actiniaria, Hormathiidae) from the eastern Weddell Sea, Antarctica  

NASA Astrophysics Data System (ADS)

A new species of sea anemone in the genus Hormathia, is described and illustrated based on forty-two specimens collected during the Polarstern cruises ANT XV/3 and ANT XVII/3 in the Weddell Sea. The main features of the new taxon are the crown of flattened and hooked tubercles at the distal end of the scapus, the regular arrangement of pointed tubercles along the column and the cnidom. The new species shares the pointed tubercles, at least in the upper part of the scapus, with two other species of Hormathia in the southern hemisphere: Hormathia spinosa Hertwig 1882 and H. pectinata Hertwig 1882

Rodríguez, Estefanía; López-González, Pablo

2001-04-01

263

Cnidarian microRNAs frequently regulate targets by cleavage.  

PubMed

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

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

2014-04-01

264

Anti-hepatoma activity in mice of a polysaccharide from the rhizome of Anemone raddeana.  

PubMed

A neutral polysaccharide fraction (ARP) prepared from the rhizome of Anemone raddeana was tested for its anticancer activity in H22 tumor-bearing mice by oral administration. ARP could not only significantly inhibit the growth of H22 transplantable tumor, but also remarkably promote splenocytes proliferation, NK cell and CTL activity, as well as serum IL-2 and TNF-? production in tumor-bearing mice. In addition, ARP treatment to tumor bearing mice had no toxicity to body weight, the liver and kidney. Moreover it could reverse the hematological parameters induced by 5-fluorouracil (5-FU) to near normal. The above results suggested that the antitumor activity of ARP might be achieved by improving immune response, and they could act as antitumor agent with immunomodulatory activity. PMID:22301002

Liu, Yang; Li, Yiming; Yang, Wenbin; Zhang, Li; Cao, Gang

2012-04-01

265

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

NASA Astrophysics Data System (ADS)

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.

Peck, Lloyd S.; Brockington, Simon

2013-08-01

266

Observations of Chromospheric Anemone Jets with Hinode CaII Broadband Filtergraph and Hida CaII Spectroheliograph  

NASA Astrophysics Data System (ADS)

We report on the first simultaneous observations of chromospheric ``anemone'' jets in solar active regions with the Hinode Solar Optical Telescope (SOT) CaII H broadband filtergraph and the CaII K spetroheliograph on the Domeless Solar Telescope (DST) at Hida Observatory. During the period of coordinated observations, nine chromospheric anemone jets were simultaneously observed with the two instruments. These observations revealed three important features: (1) the jets are generated in the lower chromosphere; i.e., these cannot be seen in CaII K3; (2) the length and lifetime of the jets are 0.4-5 Mm and 40-320 s, respectively; (3) the apparent velocity of the jets observed with the SOT is 3-24 km s-1, while the CaII K3 component at the jets shows a blueshift (in 5 events) in the range of 2-6 km s-1. The chromospheric anemone jets are associated with mixed polarity regions, which are either small emerging flux regions or moving magnetic features. It is found that the CaII K line often shows red or blue asymmetry in the K2/K1 component; the footpoint of the jets associated with emerging flux regions often shows a redshift (2-16 km s-1), while the one with moving magnetic features shows a blueshift (˜5 km s-1). A detailed analysis of the magnetic evolution of the jet-forming regions revealed that the reconnection rate (or canceling rate) of the total magnetic flux at the footpoint of the jets is on the order of 1016 Mx s-1, and the resulting magnetic energy release rate is (1.1-10) × 1024 erg s-1, with a total energy release of (1-13) × 1026 erg for the duration of the magnetic cancellation, ˜130 s. These are comparable to the estimated total energy, ˜1026 erg, in a single chromospheric anemone jet. In addition to the DST CaII K spectroheliogram and the SOT CaII H broadband filtergram, we also used for analysis an SOT magnetogram as well as a Hida H? filtergram. We present a physical model of the jet based on the observation, and discuss the relation between chromospheric anemone jets and Ellerman bombs.

Morita, Satoshi; Shibata, Kazunari; Ueno, Satoru; Ichimoto, Kiyoshi; Kitai, Reizaburo; Otsuji, Ken-Ichi

2010-08-01

267

Unravelling the nature of Waiparaconus, a pennatulacean (Cnidaria: Octocorallia) from the Late Mesozoic-Early Cainozoic of the Southern Hemisphere.  

PubMed

Enigmatic calcareous conical fossils have been known from marine Paleocene-Eocene sequences of New Zealand since the early 1870s. More recently, similar fossils have been recorded from both Late Cretaceous marine sequences of Western Australia, New Caledonia and Antarctica, and possibly from the Eocene of South America. The present paper extends the record to the late Cretaceous of New Caledonia. These remains are unlike any living taxa, and have been variously interpreted as molluscs (rudistid bivalves), cirripedes (stalked barnacles), annelids and inorganic structures. Assignation to the Cirripedia has been refuted by Buckeridge (1983, 1993), who proposed that the material would be better placed within the Cnidaria. We investigate this hypothesis in light of the New Caledonian material and by comparison with living gorgonians and pennatulaceans, and demonstrate that Waiparaconus is best placed within the Pennatulacea. Waiparaconus zelandicus varies in form somewhat, with 3 morphotypes defined and reinforced by geography. Comment is provided on the imperative to fit organic remains into known groups, with reflection on what may happen if taxa are left in insertae sedis. PMID:24673757

Buckeridge, John S; Campbell, Hamish J; Maurizot, Pierre

2014-03-01

268

Structure-function studies of tryptophan mutants of equinatoxin II, a sea anemone pore-forming protein.  

PubMed Central

Equinatoxin II (EqtII) is a eukaryotic cytolytic toxin that avidly creates pores in natural and model lipid membranes. It contains five tryptophan residues in three different regions of the molecule. In order to study its interaction with the lipid membranes, three tryptophan mutants, EqtII Trp(45), EqtII Trp(116/117) and EqtII Trp(149), were prepared in an Escherichia coli expression system [here, the tryptophan mutants are classified according to the position of the remaining tryptophan residue(s) in each mutated protein]. They all possess a single intrinsic fluorescent centre. All mutants were less haemolytically active than the wild-type, although the mechanism of erythrocyte damage was the same. EqtII Trp(116/117) resembles the wild-type in terms of its secondary structure content, as determined from Fourier-transform infrared (FTIR) spectra and its fluorescent properties. Tryptophans at these two positions are buried within the hydrophobic interior of the protein, and are transferred to the lipid phase during the interaction with the lipid membrane. The secondary structure of the other two mutants, EqtII Trp(45) and EqtII Trp(149), was altered to a certain extent. EqtII Trp(149) was the most dissimilar from the wild-type, displaying a higher content of random-coil structure. It also retained the lowest number of nitrogen-bound protons after exchange with (2)H(2)O, which might indicate a reduced compactness of the molecule. Tryptophans in EqtII Trp(45) and EqtII Trp(149) were more exposed to water, and also remained as such in the membrane-bound form.

Malovrh, P; Barlic, A; Podlesek, Z; MaCek, P; Menestrina, G; Anderluh, G

2000-01-01

269

Early development of young brooded in the enteron of the beadlet sea anemone Actinia equina (Anthozoa: Actiniaria) from Japan  

Microsoft Academic Search

Histological observations were made to reveal the origin of young brooded in the enteron of adult Actinia equina from Japan. A total of 295 specimens were collected from four rocky intertidal areas of Sagami Bay and eastern Suruga Bay, Pacific coast of Japan, during the period from February 1994 to January 1995. In the enteron of adults, regardless of sex,

KENSUKE YANAGI; SUSUMU SEGAWA; KOTARO TSUCHIYA

1999-01-01

270

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

PubMed

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

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

2014-06-01

271

Pore formation by the sea anemone cytolysin equinatoxin II in red blood cells and model lipid membranes  

Microsoft Academic Search

The interaction ofActinia equina equinatoxin II (EqT-II) with human red blood cells (HRBC) and with model lipid membranes was studied. It was found that HRBC hemolysis by EqT-II is the result of a colloid-osmotic shock caused by the opening of toxin-induced ionic pores. In fact, hemolysis can be prevented by osmotic protectants of adequate size. The functional radius of the

Giovanna Belmonte; Cecilia Pederzolli; Peter Ma?ek; Gianfranco Menestrina

1993-01-01

272

Sea Anemone Toxin: A Tool to Study Molecular Mechanisms of Nerve Conduction and Excitation-Secretion Coupling  

Microsoft Academic Search

The effects of a polypeptide neurotoxin from Anemonia sulcata on nerve conduction in crayfish giant axons and on frog myelinated fibers have been analyzed. The main features of toxin action are the following: (i) the toxin acts at very low doses and its action is apparently irreversible. (ii) The toxin selectively affects the closing (inactivation) of the Na+ channel by

G. Romey; J. P. Abita; H. Schweitz; G. Wunderer; M. Lazdunski

1976-01-01

273

Crystal Structure of the Soluble Form of Equinatoxin II, a PoreForming Toxin from the Sea Anemone Actinia equina  

Microsoft Academic Search

Background: Membrane pore–forming toxins have a remarkable property: they adopt a stable soluble form structure, which, when in contact with a membrane, undergoes a series of transformations, leading to an active, membrane-bound form. In contrast to bacterial toxins, no structure of a pore-forming toxin from an eukaryotic organism has been determined so far, an indication that structural studies of equinatoxin

Alekos Athanasiadis; Gregor Anderluh; Peter Ma?ek; Dušan Turk

2001-01-01

274

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

NASA Astrophysics Data System (ADS)

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.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. Electronic supplementary information (ESI) available: Synthesis and characterization procedures, TEM/XRD of samples prepared at different temperature and water content, table of nitrogen adsorption-desorption values of different samples. See DOI: 10.1039/c3nr06154j

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

2014-05-01

275

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.

276

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)

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.

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

2008-01-01

277

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.

278

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

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

279

Mitochondrial DNA of Hydra attenuata (Cnidaria): A Sequence That Includes an End of One Linear Molecule and the Genes for l-rRNA, tRNA f-Met , tRNA Trp , COII, and ATPase8  

Microsoft Academic Search

.   The 3231-nucleotide-pair (ntp) sequence of one end of one of the two linear mitochondrial (mt) DNA molecules of Hydra attenuata (phylum Cnidaria, class Hydrozoa, order Anthomedusae) has been determined. This segment contains complete genes for tRNAf-Met, l-rRNA, tRNATrp, subunit 2 of cytochrome c oxidase (COII), subunit 8 of ATP synthetase (ATPase8), and the 5? 136 ntp of ATPase6. These

Genevieve Pont-Kingdon; Cecile G. Vassort; Rahul Warrior; Ronald Okimoto; C. Timothy Beagley; David R. Wolstenholme

2000-01-01

280

Atlantic Leptolida (Hydrozoa, Cnidaria) of the families Aglaopheniidae, Halopterididae, Kirchenpaueriidae and Plumulariidae collected during the CANCAP and Mauritania-II expeditions of the National Museum of Natural History, Leiden, the Netherlands  

Microsoft Academic Search

Forty-six species of the superfamily Plumularioidea (Hydrozoa, Cnidaria) and some material identified to the generic level, collected by the CANCAP and Mauritania-II expeditions of the Rijkmuseum van Natuurlijke Historie (now Nationaal Natuurhistorisch Museum) in the period 1976-1988, are described, as well as two other species that were used in the present study. In addition to the descriptions, synonymy, variability and

J. Ansín Agís; W. Vervoort; F. Ramil

2001-01-01

281

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

PubMed

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

Bergmann, Melanie; Klages, Michael

2012-12-01

282

Sea urchin  

NSDL National Science Digital Library

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.

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

2004-12-23

283

Red Sea  

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 and the Saudi Arabian peninsula, the Red Sea got its name because the blooms of a type of algae,  Trichodesmium ...

2013-04-16

284

Sea Turtles  

NSDL National Science Digital Library

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.

Productions, Jonathan B.

2010-03-29

285

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).

2008-01-01

286

A purified Palythoa venom fraction delays sodium current inactivation in sympathetic neurons.  

PubMed

Palythoa caribaeorum is a zoanthid (Phylum Cnidaria, class Anthozoa) commonly found in shallow waters of coral reefs along the Mexican Atlantic coast. Little is known on the pharmacological and biochemical properties of the venom components of this animal group. Toxin peptides from other cnidarian venoms, like sea anemones, target sodium and potassium voltage-gated channels. In this study, we tested the activity of a low molecular weight fraction from the venom of P. caribaeorum on voltage-gated sodium channels of the superior cervical ganglion (SCG) neurons of the rat. Our results showed that this fraction delays tetrodotoxin (TTX)-sensitive sodium channel inactivation indicated by a reversible 2-fold increase of the current at the decay. A peptide responsible for this activity was isolated and characterized. Its sequence showed that it does not resemble any previously reported toxin. Together, these results evidence the presence of neurotoxins in P. caribaeorum that act on sodium channels. PMID:24593961

Lazcano-Pérez, Fernando; Vivas, Oscar; Román-González, Sergio A; Rodríguez-Bustamante, Eduardo; Castro, Héctor; Arenas, Isabel; García, David E; Sánchez-Puig, Nuria; Arreguín-Espinosa, Roberto

2014-05-01

287

New taxa and revisionary systematics of alcyonacean octocorals from the Pacific coast of North America (Cnidaria, Anthozoa)  

PubMed Central

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.

Williams, Gary C.

2013-01-01

288

Venom present in sea anemone (Heteractis magnifica) induces apoptosis in non-small-cell lung cancer A549 cells through activation of mitochondria-mediated pathway.  

PubMed

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

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

2014-03-01

289

Sea-anemone toxin ATX-II elicits A-fiber-dependent pain and enhances resurgent and persistent sodium currents in large sensory neurons  

PubMed Central

Background Gain-of-function mutations of the nociceptive voltage-gated sodium channel Nav1.7 lead to inherited pain syndromes, such as paroxysmal extreme pain disorder (PEPD). One characteristic of these mutations is slowed fast-inactivation kinetics, which may give rise to resurgent sodium currents. It is long known that toxins from Anemonia sulcata, such as ATX-II, slow fast inactivation and skin contact for example during diving leads to various symptoms such as pain and itch. Here, we investigated if ATX-II induces resurgent currents in sensory neurons of the dorsal root ganglion (DRGs) and how this may translate into human sensations. Results In large A-fiber related DRGs ATX-II (5 nM) enhances persistent and resurgent sodium currents, but failed to do so in small C-fiber linked DRGs when investigated using the whole-cell patch-clamp technique. Resurgent currents are thought to depend on the presence of the sodium channel ?4-subunit. Using RT-qPCR experiments, we show that small DRGs express significantly less ?4 mRNA than large sensory neurons. With the ?4-C-terminus peptide in the pipette solution, it was possible to evoke resurgent currents in small DRGs and in Nav1.7 or Nav1.6 expressing HEK293/N1E115 cells, which were enhanced by the presence of extracellular ATX-II. When injected into the skin of healthy volunteers, ATX-II induces painful and itch-like sensations which were abolished by mechanical nerve block. Increase in superficial blood flow of the skin, measured by Laser doppler imaging is limited to the injection site, so no axon reflex erythema as a correlate for C-fiber activation was detected. Conclusion ATX-II enhances persistent and resurgent sodium currents in large diameter DRGs, whereas small DRGs depend on the addition of ?4-peptide to the pipette recording solution for ATX-II to affect resurgent currents. Mechanical A-fiber blockade abolishes all ATX-II effects in human skin (e.g. painful and itch-like paraesthesias), suggesting that it mediates its effects mainly via activation of A-fibers.

2012-01-01

290

Genetic divergence between colour morphs in populations of the common intertidal sea anemones Actinia equina and A. prasina (Anthozoa: Actiniaria) in the Isle of Man  

Microsoft Academic Search

A distinctive morph ofActinia equina (L.) is found at low frequency among populations on intertidal hard substrata on some shores on the Isle of Man. This morph is red with rows of green oval spots or elongate markings running longitudinally down the column. Starch gel electrophoresis of 21 allozyme loci was used to compare samples of this morph from two

A. M. Solé-Cava; J. P. Thorpe

1992-01-01

291

Sizing the Radius of the Pore Formed in Erythrocytes and Lipid Vesicles by the Toxin Sticholysin I from the Sea Anemone Stichodactyla helianthus  

Microsoft Academic Search

.   The radius of the pore formed by sticholysin I and II (StI, StII) in erythrocytes and sticholysin I in lipid vesicles was\\u000a investigated. The rate of colloid osmotic lysis of human erythrocytes, exposed to one of the toxins in the presence of sugars\\u000a of different size, was measured. The relative permeability of each sugar was derived and the pore

M. Tejuca; M. Dalla Serra; C. Potrich; C. Alvarez; G. Menestrina

2001-01-01

292

The effects of asexual reproduction and inter-genotypic aggression on the genotypic structure of populations of the sea anemone Actinia tenebrosa  

Microsoft Academic Search

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

D. J. Ayre

1983-01-01

293

Ion and nonelectrolyte permeability properties of channels formed in planar lipid bilayer membranes by the cytolytic toxin from the sea anemone, Stoichactis helianthus  

Microsoft Academic Search

Summary When present at nanomolar concentrations on one side of a lipid bilayer membrane,helianthus toxin (a protein of mol wt?16,000) increases enormously membrane permeability to ions and nonelectrolytes by forming channels in the membrane. Membranes containing sphingomyelin are especially sensitive to toxin, but sphingomyelin isnot required for toxin action. Conductance is proportional to about the 4th power of toxin concentration.

Wamberto Varanda; Alan Finkelstein

1980-01-01

294

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.

295

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)

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.

Bianchelli, S.; Gambi, C.; Zeppilli, D.; Danovaro, R.

2010-03-01

296

A vertical wall dominated by Acesta excavata and Neopycnodonte zibrowii, part of an undersampled group of deep-sea habitats.  

PubMed

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

Johnson, Mark P; White, Martin; Wilson, Annette; Würzberg, Laura; Schwabe, Enrico; Folch, Helka; Allcock, A Louise

2013-01-01

297

Black Sea  

NASA Technical Reports Server (NTRS)

The Black Sea in eastern Russia is experiencing an ongoing phytoplankton bloom. This image, the most recent in a series that began in early may, shows the waters to be even more colorful than before. part of the increased brightness may be due to the presence of sun glint , especially in the center of the sea. However, more organisms appear to be present as well, their photosynthetic pigments reflecting different wavelengths of light.This Moderate Resolution Imaging Spectroradiometer (MODIS) image was captured on June 15, 2002.

2002-01-01

298

Sea Ice  

NASA Technical Reports Server (NTRS)

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.

Perovich, D.; Gerland, S.; Hendricks, S.; Meier, Walter N.; Nicolaus, M.; Richter-Menge, J.; Tschudi, M.

2013-01-01

299

Aiptasia pulchella: a tropical cnidarian representative for laboratory ecotoxicological research.  

PubMed

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

Howe, Pelli Louise; Reichelt-Brushett, Amanda Jean; Clark, Malcolm William

2012-11-01

300

Sea World  

NSDL National Science Digital Library

This is an 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.

2012-09-07

301

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

NASA Astrophysics Data System (ADS)

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.

Moses, Christopher S.; Swart, Peter K.; Dodge, Richard E.

2006-09-01

302

First Evidence of Inbreeding, Relatedness and Chaotic Genetic Patchiness in the Holoplanktonic Jellyfish Pelagia noctiluca (Scyphozoa, Cnidaria)  

PubMed Central

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.

Aglieri, Giorgio; Papetti, Chiara; Zane, Lorenzo; Milisenda, Giacomo; Boero, Ferdinando; Piraino, Stefano

2014-01-01

303

Natural Selection and Neutral Evolution Jointly Drive Population Divergence between Alpine and Lowland Ecotypes of the Allopolyploid Plant Anemone multifida (Ranunculaceae)  

PubMed Central

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.

McEwen, Jamie R.; Vamosi, Jana C.; Rogers, Sean M.

2013-01-01

304

Sea Cucumbers  

NSDL National Science Digital Library

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? Itâs 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.

2009-01-01

305

Regulation of intracellular pH in cnidarians: response to acidosis in Anemonia viridis.  

PubMed

The regulation of intracellular pH (pHi) is a fundamental aspect of cell physiology that has received little attention in studies of the phylum Cnidaria, which includes ecologically important sea anemones and reef-building corals. Like all organisms, cnidarians must maintain pH homeostasis to counterbalance reductions in pHi, which can arise because of changes in either intrinsic or extrinsic parameters. Corals and sea anemones face natural daily changes in internal fluids, where the extracellular pH can range from 8.9 during the day to 7.4 at night. Furthermore, cnidarians are likely to experience future CO?-driven declines in seawater pH, a process known as ocean acidification. Here, we carried out the first mechanistic investigation to determine how cnidarian pHi regulation responds to decreases in extracellular and intracellular pH. Using the anemone Anemonia viridis, we employed confocal live cell imaging and a pH-sensitive dye to track the dynamics of pHi after intracellular acidosis induced by acute exposure to decreases in seawater pH and NH?Cl prepulses. The investigation was conducted on cells that contained intracellular symbiotic algae (Symbiodinium sp.) and on symbiont-free endoderm cells. Experiments using inhibitors and Na?-free seawater indicate a potential role of Na?/H? plasma membrane exchangers (NHEs) in mediating pHi recovery following intracellular acidosis in both cell types. We also measured the buffering capacity of cells, and obtained values between 20.8 and 43.8 mM per pH unit, which are comparable to those in other invertebrates. Our findings provide the first steps towards a better understanding of acid-base regulation in these basal metazoans, for which information on cell physiology is extremely limited. PMID:24256552

Laurent, Julien; Venn, Alexander; Tambutté, Éric; Ganot, Philippe; Allemand, Denis; Tambutté, Sylvie

2014-02-01

306

The macrofauna of a stony sand area in the German Bight (North Sea)  

NASA Astrophysics Data System (ADS)

The sublittoral macrofauna of the Steingrund, a stony area east-northeast of Helgoland, was investigated from May till October 1991 using a van Veen grab and a small dredge. The diverse endo- and epifauna of the sandy bottoms, pebbles and boulders of this Saalian end moraine comprised 289 taxa, whereby the polychaetes Magelona papillicornis, Lanice conchilega and Spiophanes bombyx dominated in terms of abundance. Species rare in the German Bight, such as the sponge Leucandra fistulosa, the sea urchin Echinus esculentus, and the sea anemone Haliplanella lineata, were also found. The two sample sets were processed separately with multivariate techniques, and differentiated on the basis of occurrence and numbers of the abundant species. The analysis of the grab samples revealed two types of the Tellina-fabula-community. These associations were differentiated by the presence of species of the coarse-sand-inhabiting Goniadella-Spisula-community and were related to the distribution of the grain size of the sediment. Likewise, two epifaunal assemblages were distinguished. Sandy bottoms were characterized by Ophiura albida, Liocarcinus holsatus and Pagurus bernhardus, while boulders and pebbles were covered by a varied sessile and mobile epifauna dominated by the sessile bryozoan Flustra foliacea and the mobile pantopode Aechelia echinata. Numerical density, biomass and annual production estimates are in the range of values determined for the macrobenthos of the German Bight, while annual P/B ratios mounted up to 5.

Kühne, S.; Rachor, E.

1996-12-01

307

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....

308

Mammals of the Sea.  

ERIC Educational Resources Information Center

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)

Naturescope, 1986

1986-01-01

309

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. ...

310

Sea Ice  

NASA Technical Reports Server (NTRS)

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.

Parkinson, Claire L.; Cavalieri, Donald J.

2005-01-01

311

The Discovery of New Deep-Sea Hydrothermal Vent Communities in the Southern Ocean and Implications for Biogeography  

PubMed Central

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.

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

312

Colorful Underwater Sea Creatures  

ERIC Educational Resources Information Center

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…

McCutcheon, Heather

2011-01-01

313

The Baltic Sea.  

National Technical Information Service (NTIS)

The Baltic Sea is one of the largest internal seas in Europe. The Baltic's significance in the history of our Motherland is great. The following questions are presented in the brochure: A political map of the Baltic Sea, NATO and the Baltic Sea; the strug...

L. P. Altman

1971-01-01

314

Beaufort Sea: information update  

SciTech Connect

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.

Becker, P.R.

1988-04-01

315

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.

316

Age, Growth, Reproduction and Feeding of the Spurdog ( Squalus acanthias Linnaeus, 1758) in the South-eastern Black Sea  

NASA Astrophysics Data System (ADS)

Life-history parameters and diet of spurdog ( Squalus acanthias) sampled from the SE Black Sea were studied. Spurdog from age classes I to XIV were identified, with a dominance of age class VIII for both sexes. The length-weight relationship was W=0·0040*L 2·95and the mean annual growth rates in length and weight were 7·2 cm and 540·1 g, respectively. The estimated von Bertalanffy growth parameters were: W ?=12021 (g), L ?=157 (cm), K=0·12 (year -1) and t 0=-1·30 (year). The size at first maturity was 82 cm for males and 88 cm for females. Mean biennial fecundity was also found to be 8 pups/female. The relationships between fecundity-length, fecundity-weight and fecundity-age were found to be: F=-17·0842+0·2369*L (R=0·93), F=0·3780+0·0018*W (R=0·89) and F =-0·7859+1·1609*A (R=0·94) respectively. The spurdog can be considered an opportunistic feeder. Their natural diet was composed mainly of teleost fishes, followed by Crustaceans, Nematodes and Actinarians (=sea anemones). Whiting ( Merlangius merlangus euxinus) was the predominant prey item among their fish prey. Demersal teleosts formed the majority of the diet, and there was no difference ( P>0·05) among the food items of immature, maturing and mature individuals of both sexes.

Avsar, D.

2001-02-01

317

Sea Surface Temperatures  

NSDL National Science Digital Library

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.

1999-10-30

318

Sea Turtle Populations  

NSDL National Science Digital Library

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.

Twin Cities Public Television, Inc.

2007-01-01

319

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....

320

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.

321

All That Unplowed Sea  

ERIC Educational Resources Information Center

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)

MOSAIC, 1975

1975-01-01

322

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.

323

NOAA Sea Level Trends  

NSDL National Science Digital Library

The NOAA Sea Level Trends map illustrates U.S. regional and some international trends in sea level, with arrows representing the direction and magnitude of change. Students can investigate sea level changes around the U.S. and some worldwide using an interactive map interface with supporting data plots and tables.

Center For Operational Oceanographic Products And Services, Noaa

324

Sea level changes  

SciTech Connect

The paper develops an approach to the issues relating to sea level change that will assist the non-scientist and the applied scientist in making the most effective use of our existing and developing knowledge. The human perception of ''sea level'' and how that changes as societies change and develop are discussed. After some practical perspectives on the relationships between societies and sea levels are developed, an approach to developing the best available local prediction of sea level changes is outlined, and finally present knowledge and uncertainties about the future course of events that will influence ''sea level'' as defined in the practical sense is discussed.

Buddemeier, R.W.

1987-08-21

325

Dust Storm, Aral Sea  

NASA Technical Reports Server (NTRS)

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

2002-01-01

326

Variability of Sea Surface Circulation in the Japan Sea  

Microsoft Academic Search

Composite sea surface dynamic heights (CSSDH) are calculated from both sea surface dynamic heights that are derived from altimetric data of ERS-2 and mean sea surface that is calculated by a numerical model. The CSSDH are consistent with sea surface temperature obtained by satellite and observed water temperature. Assuming the geostrophic balance, sea surface current velocities are calculated. It is

Akihiko Morimoto; Tetsuo Yanagi

2001-01-01

327

Sea Ice Variability in the Bering Sea  

NASA Astrophysics Data System (ADS)

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.

Li, L.; Miller, A. J.; McClean, J.; Eisenman, I.; Hendershott, M.

2013-12-01

328

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.

329

National Sea Grant Library  

NSDL National Science Digital Library

The National Sea Grant Library (NSGL) is the digital library and official archive for NOAA Sea Grant documents. It is the only comprehensive collection of Sea Grant Âfunded documents from over 30 programs and projects across the country. This collection encompasses a wide variety of subjects, including oceanography, marine education, aquaculture, fisheries, aquatic nuisance species, coastal hazards, seafood safety, limnology, coastal zone management, marine recreation, and law.

330

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.

331

Recovery of Benthic Megafauna from Anthropogenic Disturbance at a Hydrocarbon Drilling Well (380 m Depth in the Norwegian Sea)  

PubMed Central

Recovery from disturbance in deep water is poorly understood, but as anthropogenic impacts increase in deeper water it is important to quantify the process. Exploratory hydrocarbon drilling causes physical disturbance, smothering the seabed near the well. Video transects obtained by remotely operated vehicles were used to assess the change in invertebrate megafaunal density and diversity caused by drilling a well at 380 m depth in the Norwegian Sea in 2006. Transects were carried out one day before drilling commenced and 27 days, 76 days, and three years later. A background survey, further from the well, was also carried out in 2009. Porifera (45% of observations) and Cnidaria (40%) dominated the megafauna. Porifera accounted for 94% of hard-substratum organisms and cnidarians (Pennatulacea) dominated on the soft sediment (78%). Twenty seven and 76 days after drilling commenced, drill cuttings were visible, extending over 100 m from the well. In this area there were low invertebrate megafaunal densities (0.08 and 0.10 individuals m?2) in comparison to pre-drill conditions (0.21 individuals m?2). Three years later the visible extent of the cuttings had reduced, reaching 60 m from the well. Within this area the megafaunal density (0.05 individuals m?2) was lower than pre-drill and reference transects (0.23 individuals m?2). There was a significant increase in total megafaunal invertebrate densities with both distance from drilling and time since drilling although no significant interaction. Beyond the visible disturbance there were similar megafaunal densities (0.14 individuals m?2) to pre-drilling and background surveys. Species richness, Shannon-Weiner diversity and multivariate techniques showed similar patterns to density. At this site the effects of exploratory drilling on megafaunal invertebrate density and diversity seem confined to the extent of the visible cuttings pile. However, elevated Barium concentration and reduced sediment grain size suggest persistence of disturbance for three years, with unclear consequences for other components of the benthic fauna.

Gates, Andrew R.; Jones, Daniel O. B.

2012-01-01

332

Semi-Automated Image Analysis for the Assessment of Megafaunal Densities at the Arctic Deep-Sea Observatory HAUSGARTEN  

PubMed Central

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.

Schoening, Timm; Bergmann, Melanie; Ontrup, Jorg; Taylor, James; Dannheim, Jennifer; Gutt, Julian; Purser, Autun; Nattkemper, Tim W.

2012-01-01

333

Semi-automated image analysis for the assessment of megafaunal densities at the Arctic deep-sea observatory HAUSGARTEN.  

PubMed

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

Schoening, Timm; Bergmann, Melanie; Ontrup, Jörg; Taylor, James; Dannheim, Jennifer; Gutt, Julian; Purser, Autun; Nattkemper, Tim W

2012-01-01

334

Red sea drillings  

USGS Publications Warehouse

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.

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

335

Getting Your Sea Legs  

PubMed Central

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.

Stoffregen, Thomas A.; Chen, Fu-Chen; Varlet, Manuel; Alcantara, Cristina; Bardy, Benoit G.

2013-01-01

336

Kara Sea radioactivity assessment  

Microsoft Academic Search

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

Iolanda Osvath; Pavel P Povinec; Murdoch S Baxter

1999-01-01

337

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.

338

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...

339

Sea Level Changes.  

National Technical Information Service (NTIS)

The paper develops an approach to the issues relating to sea level change that will assist the non-scientist and the applied scientist in making the most effective use of our existing and developing knowledge. The human perception of ''sea level'' and how...

R. W. Buddemeier

1987-01-01

340

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...

341

Sea Level Viewer  

NSDL National Science Digital Library

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.

Jackson, Randall; Nasa, For

342

White Sea - Russia  

NASA Technical Reports Server (NTRS)

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.

2002-01-01

343

Bering Sea Expedition  

NSDL National Science Digital Library

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.

Curriculum, Alaska S.; Grant, Alaska S.

344

Anemone: adaptive network memory engine  

Microsoft Academic Search

There is a constant battle to break-even between continuing improvements in DRAM capacities and the demands for even more memory by modern memory-intensive high-performance applications. Such applications do not take long to hit the physical memory limit and start paging to disk, which in turn considerably slows down their performance. We tackle this problem in the Adaptive Network Memory Engine

Michael R. Hines; Mark Lewandowski; Kartik Gopalan

2005-01-01

345

Epibenthic assemblages in the Celtic Sea and associated with the Jones Bank  

NASA Astrophysics Data System (ADS)

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.

Ellis, J. R.; Martinez, I.; Burt, G. J.; Scott, B. E.

2013-10-01

346

Global sea level rise  

SciTech Connect

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.

Douglas, B.C. (NOAA, Rockville, MD (USA))

1991-04-15

347

Distribution of coccolithophores in marginal seas along the western Pacific Ocean and in the Red Sea  

Microsoft Academic Search

The distribution of coccolithophores was studied in the neritic environment along the western margin of the Pacific Ocean: the Inland Sea of Seto, Yellow Sea, East China Sea, South China Sea, Java Sea, Timor Sea, Arafura Sea and Gulf of Carpentaria. The coccolithophore community in the Red Sea was also studied for comparison with the Pacific marginal seas. With minor

H. Okada; S. Honjo

1975-01-01

348

Is the Sea Level?  

NSDL National Science Digital Library

In this video-based activity, students learn that sea level is an average measurement of the height of the ocean, and sea level changes with the seasons and over time. El Niño and La Ninña events are compared, demonstrating that sea height is a function of temperature.Summary background information, data and images supporting the activity are available on the Earth Update data site. To complete the activity, students will need to access the Space Update multimedia collection, which is available for download and purchase for use in the classroom.

349

Is The Sea Level?  

NSDL National Science Digital Library

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).

2007-12-12

350

Dead sea water intoxication.  

PubMed

Near drowning in the Dead Sea is associated with both respiratory manifestations and severe electrolyte abnormalities. It is often difficult to distinguish between the contributions of sea water aspiration or ingestion to clinical manifestations. We present a unique case of accidental ingestion of a large amount of Dead Sea water through a gastrostomy tube in which a patient with familial dysautonomia presented with severe electrolyte disturbances. Forced diuresis with large amounts of intravenous fluids resulted in clinical and biochemical improvement. Full recovery was achieved after 2 days of treatment. PMID:22863826

Levy-Khademi, Floris; Brooks, Rebecca; Maayan, Channa; Tenenbaum, Ariel; Wexler, Isaiah D

2012-08-01

351

Arctic Sea Ice  

NSDL National Science Digital Library

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.

Meier, Beverly L.

2012-06-26

352

Sea level variation  

NASA Technical Reports Server (NTRS)

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.

Douglas, Bruce C.

1992-01-01

353

The north Sulu Sea productivity  

NASA Astrophysics Data System (ADS)

The Sulu Sea is a part of the western North Pacific. It is a closed sea for its deep water and a semi-closed sea for its upper layer. The Sulu Sea exchanges mainly surface waters with the South China Sea and the Celebes Sea. The Sulu Sea is more productive than the adjacent South China Sea (Jones, 2002). On the basis of MERIS satellite observations from 2002 to 2008, we focus on the high-chlorophyll area as an indicator of the abundance of primary productivity in the Sulu Sea. Strong chlorophyll concentration in the north Sulu Sea close to the Mindoro Strait mainly occurs from December to March and low chlorophyll concentration happens in April to November. The adjacent South China Sea on the other side of Mindoro Strait has shown persistent signs of low chlorophyll concentration. Based on 1/8° Global Navy Coastal Ocean Model, the intrusion of the South China Sea waters through the Mindoro Strait to the Sulu Sea from April to November is the main reason for the low chlorophyll concentration observed in the north Sulu Sea. During April to November, the South China Sea waters flow through the Mindoro Strait and stay on the surface of the north Sulu Sea because of their low density. The north Sulu Sea waters mix with fresher waters coming from the South China Sea without new nutrients supply. When the inflow from South China Sea to Sulu Sea ceases in December to March, the upwelling due to the summer monsoon wind becomes an important mechanism supplying deep nutrients to the surface water which lead to high chlorophyll concentration. Jones, I.S.F., 2002. Primary production in the Sulu Sea. Proceedings of the Indian Academy of Sciences-Earth and Planetary Sciences 111, 209-213.

Xiao, Z.

2009-12-01

354

The rotifer fauna of arctic sea ice from the Barents Sea, Laptev Sea [2pt] and Greenland Sea  

Microsoft Academic Search

Samples from arctic sea ice were studied for their rotifer fauna. Ice core samples were collected in the northern Barents Sea and the Laptev Sea from August to October 1993 and in the Greenland Sea from July to August 1994. Eight rotifer taxa, Encentrum graingeri, Proales reinhardti, Synchaeta bacillifera, S. cecilia, S. glacialis, S. hyperborea, S. tamara and S. sp.,

Christine Friedrich; Willem H. De Smet

2000-01-01

355

Drag of the sea surface  

Microsoft Academic Search

It is shown how the drag of the sea surface can be computed from the wind speed and the sea state. The approach, applicable both for fully developed and for developing seas, is based on conservation of momentum in the boundary layer above the sea, which allows one to relate the drag to the properties of the momentum exchange between

V. K. Makin; V. N. Kudryavtsev; C. Mastenbroek

1995-01-01

356

USACE Extreme Sea levels.  

National Technical Information Service (NTIS)

HR Wallingford and Southampton University are supporting the USACE in the development of an Engineering Technical Letter (ETL), in relation to extreme sea levels and climate impact adaptation. Lead personnel responsible for the USACE are Dr Kathleen White...

2014-01-01

357

Dead Sea Scrolls  

NASA Technical Reports Server (NTRS)

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.

1994-01-01

358

Purple sea urchin swarm  

NSDL National Science Digital Library

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.

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

2007-01-04

359

Science at Sea.  

ERIC Educational Resources Information Center

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)

Phillips, Mary Nied

2001-01-01

360

Teacher at Sea.  

ERIC Educational Resources Information Center

Outlines the experiences of a teacher in the National Oceanic and Atmospheric Administration's (NOAA) Teacher At Sea Program in which teachers are placed on NOAA vessels to work with professional scientists doing critical, real world research. (DDR)

Beighley, Karl

1998-01-01

361

Sea Ice Ecosystems  

NASA Astrophysics Data System (ADS)

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.

Arrigo, Kevin R.

2014-01-01

362

Sea ice ecosystems.  

PubMed

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

Arrigo, Kevin R

2014-01-01

363

The Dead Sea monster  

Microsoft Academic Search

For a very large part of human history, the Dead Sea has been considered a prime example of an environment completely devoid\\u000a of life, a condition which during the Greco-Roman period was ascribed to natural causes—the bitterness of the water and the\\u000a hydrogen sulphide stench associated with the area. In the Middle Ages, however, attitudes towards the Dead Sea changed

Arie Nissenbaum

1992-01-01

364

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.

365

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.

2011-07-15

366

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.

367

Sea Level rise contributors  

NSDL National Science Digital Library

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.

Meier, M. F.; Dyurgerov, Mark; Center, National S.

368

Sea Level Viewer  

NSDL National Science Digital Library

This website presents ocean topography as measured by sea surface heights taken from space by NASA and CNES. Ocean heat circulation impacts weather and causes events such as Large El Nino, Hurricane Katrina, Indian Ocean Tsunami and La Nina. These events and the latest view of sea surface height are depicted with this 3D interactive viewer. Objectives of NASA missions TOPEX/Poseiden, Jason 1, and Jason 2/OSTM are charted. Closed Captioning is available.

369

Simulation and observations of annual density banding in skeletons of Montastraea (Cnidaria: Scleractinia) growing under thermal stress associated with ocean warming  

USGS Publications Warehouse

We present a model of annual density banding in skeletons of Montastraea coral species growing under thermal stress associated with an ocean-warming scenario. The model predicts that at sea-surface temperatures (SSTs) <29??C, high-density bands (HDBs) are formed during the warmest months of the year. As temperature rises and oscillates around the optimal calcification temperature, an annual doublet in the HDB (dHDB) occurs that consists of two narrow HDBs. The presence of such dHDBs in skeletons of Montastraea species is a clear indication of thermal stress. When all monthly SSTs exceed the optimal calcification temperature, HDBs form during the coldest, not the warmest, months of the year. In addition, a decline in mean-annual calcification rate also occurs during this period of elevated SST. A comparison of our model results with annual density patterns observed in skeletons of M. faveolata and M. franksi, collected from several localities in the Mexican Caribbean, indicates that elevated SSTs are already resulting in the presence of dHDBs as a first sign of thermal stress, which occurs even without coral bleaching. ?? 2007, by the American Society of Limnology and Oceanography, Inc.

Worum, F. P.; Carricart-Ganivet, J. P.; Benson, L.; Golicher, D.

2007-01-01

370

The genesis of sea level variability in the Barents Sea  

NASA Astrophysics Data System (ADS)

The regional variability of sea level is an integral indicator of changing oceanographic conditions due to different processes of oceanic, atmospheric, and terrestrial origin. The present study explores the nature of sea level variability in the Barents Sea—a marginal shelf sea of the Arctic Ocean. A characteristic feature that distinguishes this sea from other Arctic shelf seas is that it is largely ice free throughout the year. This allows continuous monitoring of sea level by space-borne altimeters. In this work we combine satellite altimetry, ocean gravity measurements by GRACE satellites, available hydrography data, and a high-resolution ocean data synthesis product to estimate the steric and mass-related components of sea level in the Barents Sea. We present one of the first observational evidence of the local importance of the mass-related sea level changes. The observed 1-3 month phase lag between the annual cycles of sea level in the Barents Sea and in the Nordic seas (Norwegian, Iceland, Greenland seas) is explained by the annual mass-related changes. The analysis of the barotropic vorticity budget shows that the mass-related sea level variability in the central part of the Barents Sea is determined by the combined effect of wind stress, flow over the varying bottom topography, and dissipation, while the impact of vorticity fluxes is negligible. Overall, the steric sea level has smaller amplitudes and mainly varies on the seasonal time scale. The thermosteric sea level is the main contributor to the steric sea level along the pathways of the Atlantic inflow into the Barents Sea. The relative contribution of the halosteric sea level is dominant in the southeastern, eastern, and northern parts of the Barents Sea, modulated by the seasonal sea ice formation/melt as well as by continental runoff. The variability of the thermosteric sea level in the Barents Sea is mostly driven by variations in the net surface heat flux, whereas the contribution of heat advection becomes as important as the ocean-atmosphere heat exchange at interannual time scales.

Volkov, Denis L.; Landerer, Felix W.; Kirillov, Sergey A.

2013-09-01

371

The White Sea, Russia  

NASA Technical Reports Server (NTRS)

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.

2002-01-01

372

Jellyfish as prey: frequency of predation and selective foraging of Boops boops (Vertebrata, Actinopterygii) on the mauve stinger Pelagia noctiluca (Cnidaria, Scyphozoa).  

PubMed

In recent years, jellyfish blooms have attracted considerable scientific interest for their potential impacts on human activities and ecosystem functioning, with much attention paid to jellyfish as predators and to gelatinous biomass as a carbon sink. Other than qualitative data and observations, few studies have quantified direct predation of fish on jellyfish to clarify whether they may represent a seasonally abundant food source. Here we estimate predation frequency by the commercially valuable Mediterranean bogue, Boops boops on the mauve stinger jellyfish, Pelagia noctiluca, in the Strait of Messina (NE Sicily). A total of 1054 jellyfish were sampled throughout one year to quantify predation by B. boops from bite marks on partially eaten jellyfish and energy density of the jellyfish. Predation by B. boops in summer was almost twice that in winter, and they selectively fed according to medusa gender and body part. Calorimetric analysis and biochemical composition showed that female jellyfish gonads had significantly higher energy content than male gonads due to more lipids and that gonads had six-fold higher energy content than the somatic tissues due to higher lipid and protein concentrations. Energetically, jellyfish gonads represent a highly rewarding food source, largely available to B. boops throughout spring and summer. During the remainder of the year, when gonads were not very evident, fish predation switched towards less-selective foraging on the somatic gelatinous biomass. P. noctiluca, the most abundant jellyfish species in the Mediterranean Sea and a key planktonic predator, may represent not only a nuisance for human leisure activities and a source of mortality for fish eggs and larvae, but also an important resource for fish species of commercial value, such as B. boops. PMID:24727977

Milisenda, Giacomo; Rosa, Sara; Fuentes, Veronica L; Boero, Ferdinando; Guglielmo, Letterio; Purcell, Jennifer E; Piraino, Stefano

2014-01-01

373

Jellyfish as Prey: Frequency of Predation and Selective Foraging of Boops boops (Vertebrata, Actinopterygii) on the Mauve Stinger Pelagia noctiluca (Cnidaria, Scyphozoa)  

PubMed Central

In recent years, jellyfish blooms have attracted considerable scientific interest for their potential impacts on human activities and ecosystem functioning, with much attention paid to jellyfish as predators and to gelatinous biomass as a carbon sink. Other than qualitative data and observations, few studies have quantified direct predation of fish on jellyfish to clarify whether they may represent a seasonally abundant food source. Here we estimate predation frequency by the commercially valuable Mediterranean bogue, Boops boops on the mauve stinger jellyfish, Pelagia noctiluca, in the Strait of Messina (NE Sicily). A total of 1054 jellyfish were sampled throughout one year to quantify predation by B. boops from bite marks on partially eaten jellyfish and energy density of the jellyfish. Predation by B. boops in summer was almost twice that in winter, and they selectively fed according to medusa gender and body part. Calorimetric analysis and biochemical composition showed that female jellyfish gonads had significantly higher energy content than male gonads due to more lipids and that gonads had six-fold higher energy content than the somatic tissues due to higher lipid and protein concentrations. Energetically, jellyfish gonads represent a highly rewarding food source, largely available to B. boops throughout spring and summer. During the remainder of the year, when gonads were not very evident, fish predation switched towards less-selective foraging on the somatic gelatinous biomass. P. noctiluca, the most abundant jellyfish species in the Mediterranean Sea and a key planktonic predator, may represent not only a nuisance for human leisure activities and a source of mortality for fish eggs and larvae, but also an important resource for fish species of commercial value, such as B. boops.

Fuentes, Veronica L.; Boero, Ferdinando; Guglielmo, Letterio; Purcell, Jennifer E.; Piraino, Stefano

2014-01-01

374

Two new UV-absorbing mycosporine-like amino acids from the sea anemone Anthopleura elegantissima and the effects of zooxanthellae and spectral irradiance on chemical composition and content  

Microsoft Academic Search

Many tropical cnidarians living in shallow water contain a class of ultraviolet-A (UV-A, 320 to 400 nm) and ultraviolet-B (UV-B, 280 to 320 nm) absorbing compounds known as mycosporine-like amino acids (MAAs). These compounds may provide protection from the deleterious effects of solar UV radiation. Using a novel application of reverse-phase high performance liquid chromatography, we find that the temperate

W. R. Stochaj; W. C. Dunlap; J. M. Shick

1994-01-01

375

The Dead Sea  

NASA Technical Reports Server (NTRS)

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

2006-01-01

376

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.

377

Geology of Barents Sea  

SciTech Connect

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.

Riis, F.; Vollset, J.

1984-09-01

378

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.

1996-01-01

379

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.

380

Mountains in the Sea  

NSDL National Science Digital Library

In this 6-7 day investigation, learners begin with an introduction to seamounts that are present in the Gulf of Alaska. They learn how seamounts were formed and look at a bathymetric map of a seamount. In Activity 3A, learners explore sea floor mapping techniques as they participate in an activity to create a map of a sea feature they have molded out of clay. In Activity 3B, learners watch a short animated presentation, "Who cares about Sea Floor Mapping?" and create a model of a seamount found in Alaska. They use pre-sonar techniques to collect data and create a graph of their seamount using Excel. This detailed lesson plan includes learner hand-outs, evaluation questions, curricular connections, and tips.

Grant, Alaska S.

2011-01-01

381

RADIOCARBON RESERVOIR AGES IN THE MEDITERRANEAN SEA AND BLACK SEA  

Microsoft Academic Search

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,

Nadine Tisnerat; Franck Bassinot

382

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.

2011-05-05

383

Melting Sea Ice  

NSDL National Science Digital Library

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.

Domain, Wgbh E.

384

Lighting Up the Sea  

NSDL National Science Digital Library

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.

2009-07-09

385

Electromagnetic Phenomena in the Sea.  

National Technical Information Service (NTIS)

Contents: Gyrocompass for magnetometric operations in the sea; Measuring the magnetic field in the sea by towed magnetometers; Errors of the ferrosonde component of a magnetometer; Tidal variation of the geomagnetic field on Franz Josef Land; Shock waves ...

V. V. Shuleikin

1970-01-01

386

Sea Gravimetry and Eotvos Correction.  

National Technical Information Service (NTIS)

A physical model for sea gravimetry, which includes the Eotvos effect, is derived. An error model for sea gravimetry, which includes Eotvos correction errors, cross coupling errors and off level errors is shown. The possibilities of obtaining ship velocit...

J. H. M. Smit

1988-01-01

387

Arctic Sea Ice Maximum 2011  

NASA Video Gallery

AMSR-E Arctic Sea Ice: September 2010 to March 2011: Scientists tracking the annual maximum extent of Arctic sea ice said that 2011 was among the lowest ice extents measured since satellites began ...

388

Seafloor Control on Sea Ice  

NASA Technical Reports Server (NTRS)

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.

Nghiem, S. V.; Clemente-Colon, P.; Rigor, I. G.; Hall, D. K.; Neumann, G.

2011-01-01

389

A deep-sea hydrothermal vent community dominated by Stauromedusae  

Microsoft Academic Search

A dense population of stauromedusan scyphozoans (morphologically similar to previously described species within the genus Lucernaria) was encountered in a previously undocumented area of hydrothermal activity along the crest of the East Pacific Rise (Lat. 20°50.304?N; Long. 109°05.422?W; depth of 2605m). A few galatheid (Munidopsis subsquamosa) and bythograeid (Bythograea thermydron) crabs and occasional anemones (Cyananthea sp.) were the only other

Richard A. Lutz; Daniel Desbruyères; Timothy M. Shank; Robert C. Vrijenhoek

1998-01-01

390

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.

391

Sea Level : Frequently Asked Questions and Answers  

NSDL National Science Digital Library

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.

2007-12-12

392

Ceramide Phosphoethanolamine Biosynthesis in Drosophila Is Mediated by a Unique Ethanolamine Phosphotransferase in the Golgi Lumen?  

PubMed Central

Sphingomyelin (SM) is a vital component of mammalian membranes, providing mechanical stability and a structural framework for plasma membrane organization. Its production involves the transfer of phosphocholine from phosphatidylcholine onto ceramide, a reaction catalyzed by SM synthase in the Golgi lumen. Drosophila lacks SM and instead synthesizes the SM analogue ceramide phosphoethanolamine (CPE) as the principal membrane sphingolipid. The corresponding CPE synthase shares mechanistic features with enzymes mediating phospholipid biosynthesis via the Kennedy pathway. Using a functional cloning strategy, we here identified a CDP-ethanolamine:ceramide ethanolamine phosphotransferase as the enzyme responsible for CPE production in Drosophila. CPE synthase constitutes a new branch within the CDP-alcohol phosphotransferase superfamily with homologues in Arthropoda (insects, spiders, mites, scorpions), Cnidaria (Hydra, sea anemones), and Mollusca (oysters) but not in most other animal phyla. The enzyme resides in the Golgi complex with its active site facing the lumen, contrary to the membrane topology of other CDP-alcohol phosphotransferases. Our findings open up an important new avenue to address the biological role of CPE, an enigmatic membrane constituent of a wide variety of invertebrate and marine organisms.

Vacaru, Ana M.; van den Dikkenberg, Joep; Ternes, Philipp; Holthuis, Joost C. M.

2013-01-01

393

Evolutionary conservation of the eumetazoan gene regulatory landscape.  

PubMed

Despite considerable differences in morphology and complexity of body plans among animals, a great part of the gene set is shared among Bilateria and their basally branching sister group, the Cnidaria. This suggests that the common ancestor of eumetazoans already had a highly complex gene repertoire. At present it is therefore unclear how morphological diversification is encoded in the genome. Here we address the possibility that differences in gene regulation could contribute to the large morphological divergence between cnidarians and bilaterians. To this end, we generated the first genome-wide map of gene regulatory elements in a nonbilaterian animal, the sea anemone Nematostella vectensis. Using chromatin immunoprecipitation followed by deep sequencing of five chromatin modifications and a transcriptional cofactor, we identified over 5000 enhancers in the Nematostella genome and could validate 75% of the tested enhancers in vivo. We found that in Nematostella, but not in yeast, enhancers are characterized by the same combination of histone modifications as in bilaterians, and these enhancers preferentially target developmental regulatory genes. Surprisingly, the distribution and abundance of gene regulatory elements relative to these genes are shared between Nematostella and bilaterian model organisms. Our results suggest that complex gene regulation originated at least 600 million yr ago, predating the common ancestor of eumetazoans. PMID:24642862

Schwaiger, Michaela; Schönauer, Anna; Rendeiro, André F; Pribitzer, Carina; Schauer, Alexandra; Gilles, Anna F; Schinko, Johannes B; Renfer, Eduard; Fredman, David; Technau, Ulrich

2014-04-01

394

An ancient role for nuclear beta-catenin in the evolution of axial polarity and germ layer segregation  

NASA Technical Reports Server (NTRS)

The human oncogene beta-catenin is a bifunctional protein with critical roles in both cell adhesion and transcriptional regulation in the Wnt pathway. Wnt/beta-catenin signalling has been implicated in developmental processes as diverse as elaboration of embryonic polarity, formation of germ layers, neural patterning, spindle orientation and gap junction communication, but the ancestral function of beta-catenin remains unclear. In many animal embryos, activation of beta-catenin signalling occurs in blastomeres that mark the site of gastrulation and endomesoderm formation, raising the possibility that asymmetric activation of beta-catenin signalling specified embryonic polarity and segregated germ layers in the common ancestor of bilaterally symmetrical animals. To test whether nuclear translocation of beta-catenin is involved in axial identity and/or germ layer formation in 'pre-bilaterians', we examined the in vivo distribution, stability and function of beta-catenin protein in embryos of the sea anemone Nematostella vectensis (Cnidaria, Anthozoa). Here we show that N. vectensis beta-catenin is differentially stabilized along the oral-aboral axis, translocated into nuclei in cells at the site of gastrulation and used to specify entoderm, indicating an evolutionarily ancient role for this protein in early pattern formation.

Wikramanayake, Athula H.; Hong, Melanie; Lee, Patricia N.; Pang, Kevin; Byrum, Christine A.; Bince, Joanna M.; Xu, Ronghui; Martindale, Mark Q.

2003-01-01

395

Evolutionary conservation of the eumetazoan gene regulatory landscape  

PubMed Central

Despite considerable differences in morphology and complexity of body plans among animals, a great part of the gene set is shared among Bilateria and their basally branching sister group, the Cnidaria. This suggests that the common ancestor of eumetazoans already had a highly complex gene repertoire. At present it is therefore unclear how morphological diversification is encoded in the genome. Here we address the possibility that differences in gene regulation could contribute to the large morphological divergence between cnidarians and bilaterians. To this end, we generated the first genome-wide map of gene regulatory elements in a nonbilaterian animal, the sea anemone Nematostella vectensis. Using chromatin immunoprecipitation followed by deep sequencing of five chromatin modifications and a transcriptional cofactor, we identified over 5000 enhancers in the Nematostella genome and could validate 75% of the tested enhancers in vivo. We found that in Nematostella, but not in yeast, enhancers are characterized by the same combination of histone modifications as in bilaterians, and these enhancers preferentially target developmental regulatory genes. Surprisingly, the distribution and abundance of gene regulatory elements relative to these genes are shared between Nematostella and bilaterian model organisms. Our results suggest that complex gene regulation originated at least 600 million yr ago, predating the common ancestor of eumetazoans.

Schwaiger, Michaela; Schonauer, Anna; Rendeiro, Andre F.; Pribitzer, Carina; Schauer, Alexandra; Gilles, Anna F.; Schinko, Johannes B.; Renfer, Eduard; Fredman, David; Technau, Ulrich

2014-01-01

396

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.

397

Sea Fighter Analysis.  

National Technical Information Service (NTIS)

The U.S. Coast Guard (CG) Research & Development Center (R&DC) evaluated the U.S. Navy's Sea Fighter vessel (FSF-1) for potential applicability for CG missions. For this evaluation, the project team used a combination of engagement modeling and simulation...

M. Hammond

2007-01-01

398

Open sea skimmer barge  

SciTech Connect

An open sea skimmer barge for use as a dredge comprising a hull having a bow, bottom, side walls, stern having a substantially horizontal elongate slot extending across a portion thereof and a deck, a spill suction tunnel, a collection tank, secondary oil separation means and tertiary oil separation means.

Ayers, W.M.

1983-04-05

399

Open sea skimmer barge  

SciTech Connect

An open sea skimmer barge comprising a hull having a bow, bottom, side walls, stern having a substantially horizontal elongate slot extending across a portion thereof and a deck, a spill suction tunnel, a collection tank, secondary oil separation means and tertiary oil separation means.

Ayers, W.M.; Maheshwary, A.K.; Young, P.J.

1984-10-16

400

Open sea skimmer barge  

SciTech Connect

An open sea skimmer barge is disclosed comprising a hull having a bow, bottom, side walls, stern having a substantially horizontal elongate slot extending across a portion thereof and a deck, a suction tunnel, a collection tank, secondary oil separation means and tertiary oil separation means.

Ayers, W.M.

1983-08-16

401

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.

402

Classroom of the Sea  

NSDL National Science Digital Library

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

Monte, Denise; Hupper, Mary L.; Scheifele, Peter

2000-03-01

403

Sea Surface Temperature  

NSDL National Science Digital Library

Explore the relationship between sea surface temperature (SST) and Earth's climate system, and consider the effects that changes in SST are having in the Arctic and beyond in this interactive activity produced for Teachers' Domain featuring data and visualization from NOAA.

Foundation, Wgbh E.

2009-08-28

404

Rising Sea Levels  

NSDL National Science Digital Library

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.

Learn, Nbc

2010-10-07

405

Alboran Sea Modeling.  

National Technical Information Service (NTIS)

A study of circulation in the Alboran Sea begins by using simplest model capable of simulating major features of the circulation. This is a reduced gravity model in a semi-enclosed rectangular domain. It is essentially a model of the first baroclinic mode...

R. H. Preller

1983-01-01

406

Classroom of the Sea.  

ERIC Educational Resources Information Center

Introduces the Sea Program in which participant students were deaf and collaborated with a bioacoustician. Studies the underwater noise levels of the Gulf of Maine and the possible impacts on marine life. Explains implementing this project in the science curriculum. (YDS)

Hupper, Mary Laporta; Monte, Denise; Scheifele, Peter

2000-01-01

407

SeaWeb  

NSDL National Science Digital Library

A multimedia public education project designed to raise awareness of the world ocean and the life within it. Find articles on the latest ocean issues, links to resources and audio clips of the radio show Ocean Report. Also features information on SeaWeb programs, such as aquaculture initiatives for both fish and their eggs (caviar), and publications.

408

Solar Sea Power  

ERIC Educational Resources Information Center

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)

Zener, Clarence

1976-01-01

409

Space Invaders at Sea  

NSDL National Science Digital Library

This radio broadcast discusses the recent issue of the increase and spread of tunicates (or 'sea squirts'), who have suddenly proliferated off the Atlantic Coast of the United States and Canada. The creatures, an invasive species likely from Asia or Europe, have carpeted the ocean floor and are smothering valuable shellfish.

Hoops, Richard

2010-10-13

410

Ships to the Sea.  

ERIC Educational Resources Information Center

This lesson contains materials for the U.S. Navy Museum's "Ships to the Sea" program. The program is appropriate for students in grades 2-4 and was designed in accordance with local and national social studies standards. The materials introduce students to the world of ship technology and naval terminology. The lesson is presented in five…

Department of the Navy, Washington, DC.

411

Farming the Sea  

ERIC Educational Resources Information Center

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)

Morgan, William

1971-01-01

412

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.

413

Autophagy at sea.  

PubMed

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

Martens, Sascha; Rusten, Tor Erik; Kraft, Claudine

2013-09-01

414

Yellow Sea Thermal Structure.  

National Technical Information Service (NTIS)

There exists a need in the oceanography community to be able to produce climatologies of remote or poorly sampled shallow water areas through remote sensing techniques. Our goal was to construct a three-dimensional thermal structure of the Yellow Sea base...

C. R. Fralick

1994-01-01

415

Sea floor magnetic observatory  

NASA Astrophysics Data System (ADS)

The electromagnetic precursors of seismic hazards are widely accepted as strong evidence of the approaching earthquake or volcano eruption. The monitoring of these precursors are of main interest in densely populated areas, what creates serious problems to extract them at the strong industrial noise background. An interesting possibility to improve signal-to-noise ratio gives the installation of the observation points in the shelf zones near the possible earthquake places, what is fairly possible in most seismically active areas in Europe, e. g. in Greece and Italy. The serious restriction for this is the cost of the underwater instrumentation. To realize such experiments it requires the unification of efforts of several countries (e. g., GEOSTAR) or of the funds of some great companies (e. g., SIO magnetotelluric instrument). The progress in electronic components development as well as the appearance of inexpensive watertight glass spheres made it possible to decrease drastically the price of recently developed sea floor magnetic stations. The autonomous vector magnetometer LEMI-301 for sea bed application is described in the report. It is produced on the base of three-component flux-gate sensor. Non-magnetic housing and minimal magnetism of electronic components enable the instrument to be implemented as a monoblock construction where the electronic unit is placed close to the sensor. Automatic circuit provides convenient compensation of the initial field offset and readings of full value (6 digits) of the measured field. Timing by internal clock provides high accuracy synchronization of data. The internal flash memory assures long-term autonomous data storage. The system also has two-axes tilt measurement system. The methodological questions of magnetometer operation at sea bed were studied in order to avoid two types of errors appearing at such experimental cases. First is sea waving influence and second one magnetometer orientation at its random positioning on the sea floor in order to get experimental data in geomagnetic coordinates frames. The analysis executed showed that first error source can not be avoided at shallow water experiments but can be easily taken into account. The special methodology and the developed software allowed to solve the second problem. It was shown that it is possible to reduce the magnetometer data collected in randomly oriented coordinate system at arbitrary position on the sea floor to the data in the frame system connected with geomagnetic coordinates. The parameters of LEMI-302 sea bed magnetometer are discussed and the experimental results of its application are presented. The research work in Ukraine was partly supported by INTAS grant 99-1102.

Korepanov, V.; Prystai, A.; Vallianatos, F.; Makris, J.

2003-04-01

416

Sea-Level Projections from the SeaRISE Initiative  

NASA Technical Reports Server (NTRS)

SeaRISE (Sea-level Response to Ice Sheet Evolution) is a community organized modeling effort, whose goal is to inform the fifth IPCC of the potential sea-level contribution from the Greenland and Antarctic ice sheets in the 21st and 22nd century. SeaRISE seeks to determine the most likely ice sheet response to imposed climatic forcing by initializing an ensemble of models with common datasets and applying the same forcing to each model. Sensitivity experiments were designed to quantify the sea-level rise associated with a change in: 1) surface mass balance, 2) basal lubrication, and 3) ocean induced basal melt. The range of responses, resulting from the multi-model approach, is interpreted as a proxy of uncertainty in our sea-level projections. http://websrv.cs .umt.edu/isis/index.php/SeaRISE_Assessment.

Nowicki, Sophie; Bindschadler, Robert

2011-01-01

417

Northern Sand Sea  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

Our topic for the weeks of April 4 and April 11 is dunes on Mars. We will look at the north polar sand sea and at isolated dune fields at lower latitudes. Sand seas on Earth are often called 'ergs,' an Arabic name for dune field. A sand sea differs from a dune field in two ways: 1) a sand sea has a large regional extent, and 2) the individual dunes are large in size and complex in form.

This VIS image was taken at 82 degrees North latitude during Northern spring. The image is completely dominated by dunes. In sand seas, it is very common for a single type of dune to occur, and for a single predominate wind to control the alignment of the dunes.

Image information: VIS instrument. Latitude 82.2, Longitude 152.5 East (207.5 West). 19 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

2005-01-01

418

Sea ice radiative forcing, sea ice area, and climate sensitivity  

NASA Astrophysics Data System (ADS)

Changes in sea ice cover affect climate sensitivity by modifying albedo and surface heat flux exchange, which in turn affect the absorbed solar radiation at the surface as well as cloud cover, atmospheric water content and poleward atmospheric heat transport. Here, we use a configuration of the Community Earth System Model 1.0.4 with a slab ocean model and a thermodynamic-dynamic sea ice model to investigate the overall net effect of feedbacks associated with the sea ice loss. We analyze the strength of the overall sea ice feedback in terms of two factors: the sensitivity of sea ice area to changes in temperature, and the sensitivity of sea ice radiative forcing to changes in sea ice area. In this model configuration, sea ice area decreases by ~3 × 1012 m2 per K of global warming, while the effective global radiative forcing per square meter of sea ice loss is ~0.1 × 10-12 W m-2. The product of these two terms (~0.3 W m-2 K-1) approximately equals the difference in climate feedback parameter found in simulations with sea ice response (1.05 W m-2 K-1) and simulations without sea ice response (1.31 W m-2 K-1 or 1.35 W m-2 K-1, depending on the method used to disable changes in sea ice cover). Thus, we find that in our model simulations, sea ice response accounts for about 20% to 22% of the climate sensitivity to an imposed change in radiative forcing. In our model, the additional radiative forcing resulting from a loss of all sea ice in the 'pre-industrial' state is comparable to but somewhat less than the radiative forcing from a doubling of atmospheric CO2 content.

Caldeira, Ken; Cvijanovic, Ivana

2014-05-01

419

North Sea Sediment Dynamics  

NASA Astrophysics Data System (ADS)

The North Sea is a semi-enclosed shelf sea attached to the North-east Atlantic and in its south-eastern part receives significant matter from river discharge and atmospheric deposition: Anthropogenic nutrients, dissolved carbon and organic compounds have elevated pristine background concentrations in the coastal strip of the North Sea since about 250 years as a consequence of intensified agriculture and industrialisation since then, In such a marine environment the legacy of old inputs and the influence of processes in the sediment on the biogeochemistry of the overlying water column increases with decreasing water depth. On the other hand the flux of particulate organic matter into the surface sediment (~15 cm depth) also increases with decreasing water depth or distance from the coast. Both effects are also described by results of ECOHAM-M simulations, the coupled pelagic-benthic ecosystem model that includes a prognostic multi-layer sediment module adopted from the global biogeochemical model HAMOCC as part of the MPI-earth-system model (MPI-ESM).The transfer from deep sea to coastal applications required different adaptations, such as changes in porosity values, in dissolution and organic matter remineralisation rates, and stoichiometries. In the model, two pelagic detritus pools, one slowly sinking with semi-labile organic matter, and one fast sinking with labile organic matter are collected in one sediment pool. After a spin-up of several hundred years the 3d-coupled model for the southern and central North Sea attains equilibrium, where the local inputs and outputs of the pelagic and benthic module are balanced. From this equilibrium state we initialised a realistic decadal run (2000-2009). Analysing the seasonal and interannual model results we found that the variability of sediment efflux in the model is low compared to the more dynamic pelagic system components, but simulated (and observed) sediment pore water profiles clearly show concentration gradients from the coast into the central North Sea. Data on organic matter concentration and quality in surface sediments along a comparable transect suggest that not only the loading with POM decreases with distance to land, but also the reactivity of organic matter, indicated by amino acid composition as a measure of the degree of protein degradation. This ageing or degradation effect can also be seen in a near-shore surface sediment core where the C/N ratio increases with depth, while the relative concentration of labile material in sedimentary organic matter decreases. We discuss how the quality of organic particulate matter could be integrated into the sediment model equations.

Paetsch, Johannes; Kuehn, Wilfried; Serna, Alexandra; Lahajnar, Niko; Emeis, Kay

2014-05-01

420

Sea Ice 1987 - 2012  

NSDL National Science Digital Library

This site features a video that illustrates both seasonal patterns and long-term changes in sea ice distribution across the Arctic Ocean. It draws data from two satellite instruments that measure emitted microwave radiation, which helps distinguish open ocean from ice. It shows that during the winter months, a layer of ice forms across vast expanses of the Arctic Ocean and each summer, more than half of that ice vanishes. Students discover that this natural cycle of freezing and thawing is influenced both by seasonal temperature variations and long-term climate change and that scientists are using satellite images to measure the distribution of Arctic sea ice in order to gain a better understanding of how it is linked to Earth's climate system.

421

Dauphin Island Sea Lab  

NSDL National Science Digital Library

Dauphin Island Sea Lab is Alabama's marine education and research center. Lab also provides a public aquarium that focuses solely on the native eco-systems of the Mobile Bay estuary. Site provides information on graduate programs, undergraduate opportunities, faculty, facilities, and news and events. Explore the Education and Aquarium sections for teacher resources and information on workshops, student summer camps, and academic-year programs.

422

Salish Sea Expeditions  

NSDL National Science Digital Library

At-sea education program combines classroom study with shipboard science studies in Puget Sound, Washington. Offers spring programs for schools and home schoolers, summer programs for families and youngsters; expeditions of 1 to 5 days involve oceanographic sampling activities, navigation and sailing responsibilities aboard a 61-foot sailing vessel. Teachers can join a preview sail to evaluate; site provides details on water quality, plankton and other studies and equipment used.

423

A Silurian sea spider  

Microsoft Academic Search

Pycnogonids (sea spiders) are marine arthropods numbering some 1,160 extant species. They are globally distributed in depths of up to 6,000metres, and locally abundant; however, their typically delicate form and non-biomineralized cuticle has resulted in an extremely sparse fossil record that is not accepted universally. There are two opposing views of their phylogenetic position: either within Chelicerata as sister group

Derek J. Siveter; Mark D. Sutton; Derek E. G. Briggs; David J. Siveter

2004-01-01

424

Dead Sea rhodopsins revisited.  

PubMed

The Dead Sea is a unique hypersaline ecosystem with near toxic magnesium levels (?2?M), dominance of divalent cations and a slightly acidic pH. Previously, we reported a haloarchaeon related to Halobacterium salinarum to dominate in a microbial bloom that developed in 1992 in the upper water layers of the lake following massive freshwater runoff. Whether this clade also dominated an earlier bloom in 1980-1982 cannot be ascertained as no samples for cultivation-independent analysis were preserved. The presence of the light-driven proton pump bacteriorhodopsin was reported in the 1980-1982 bloom of prokaryotes that had developed in the Dead Sea. To test the hypothesis that bacteriorhodopsin proton pumping may play a major role in determining what type of haloarchaea may dominate in specific bloom conditions, we compared rhodopsin genes recovered from Dead Sea biomass collected in different periods with genes coding for retinal proteins in isolated haloarchaea. Novel bacteriorhodopsin and sensory rhodopsin genes were found in samples collected in 2007 and 2010. The fact that no rhodopsin genes were recovered from samples collected during the 1992 bloom, which was dominated by a single species, suggests that different clades were present in the 1980-1982 and 1992 blooms, and that bacteriorhodopsin proton pumping did not necessarily play a determinative role in the dominance of specific halophiles in the blooms. PMID:23760932

Bodaker, Idan; Suzuki, Marcelino T; Oren, Aharon; Béjà, Oded

2012-12-01

425

Curonian Spit, Baltic Sea  

NASA Technical Reports Server (NTRS)

On July 25, 2006, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), flying on NASA's Terra satellite, captured this image of the Curonian (or Courland)spit, the Curonian Lagoon (also known as the Courland Lagoon) it encloses, and part of the Baltic Sea. Just 3,800 meters (about 12,460 feet) at its widest point, the spit encloses a lagoon of some 1,620 square kilometers (625 square miles). In this image, dark blue indicates deep water, and lighter blue indicates shallow and/or sediment-laden water. Different shades of blue distinguish the deeper Baltic Sea and the shallower Curonian Lagoon. Vegetation appears in varying shades of green, paved surfaces and bare ground appear in shades of beige and gray, and sandy areas appear off-white. Obvious sandy areas appear along the length of the spit. On the Baltic Sea side, a thin off-white band of beach runs the length of the spit; on the Curonian Lagoon side, intermittent beaches carve their way into the narrow strip of land.

2006-01-01

426

Kara Sea radioactivity assessment.  

PubMed

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 and Novaya Zemlya bays as well as soil from the shore of Abrosimov bay have shown that radionuclide contamination of the open Kara Sea is mainly due to global fallout, with smaller contributions from the Sellafield reprocessing plant, the Chernobyl accident run-off from the Ob and Yenisey rivers and local fallout. Computer modelling results have shown that maximum annual doses of approximately 1 mSv are expected for a hypothetical critical group subsisting on fish caught in the Novaya Zemlya bays whereas populations living on the mainland can be expected to receive doses at least three orders of magnitude lower. PMID:10568274

Osvath, I; Povinec, P P; Baxter, M S

1999-09-30

427

Aral Sea Evaporation (WMS)  

NSDL National Science Digital Library

The Aral Sea is actually not a sea at all, but an immense fresh water lake. In the last thirty years, more than sixty percent of the lake has disappeared because much of the river flow feeding the lake was diverted to irrigate cotton fields and rice paddies. Concentrations of salts and minerals began to rise in the shrinking body of water, leading to staggering alterations in the lakes ecology and precipitous drops in the Arals fish population. Powerful winds that blow across this part of Asia routinely pick up and deposit the now exposed lake bed soil. This has contributed to a significant reduction in breathable air quality, and crop yields have been appreciably affected due to heavily salt laden particles falling on arable land. This series of Landsat images taken in 1973, 1987 and 2000 show the profound reduction in overall area at the north end of the Aral, and a commensurate increase in land area as the floor of the sea now lies exposed.

Thomson, Joycelyn; Mitchell, Horace; Williams, Darrel

2005-02-15

428

Bering Sea in Bloom  

NASA Technical Reports Server (NTRS)

The surface waters of the Bering Sea around the Pribilof Islands, off Alaska's west coast, exhibited a dark green color on May 15, 2002, in this SeaWiFS true-color image. The green color of the currents there suggests the presence of a large phytoplankton bloom. Careful inspection reveals some a reddish tinges of light reflected by this bloom, particularly in a long east to west band just south of the Pribilof Islands, and just north of the Aleutian Island chain (disappearing toward the lower righthand corner of this scene beneath the cloud bank). Some scientists speculate this could be another Phaeocystis bloom, similar to the bloom of this species that was observed in these waters roughly this time last year. Such blooms are typically accompanied by a strong, unpleasant odor in the immediate vicinity. The light brown color of the surface waters along the Alaskan shoreline are probably due to suspended sediments washed off from the land. Image courtesy the SeaWiFS Project, NASA GSFC, and ORBIMAGE

2002-01-01

429

Sea & Ships: Explore Online  

NSDL National Science Digital Library

The National Maritime Museum (NMM) in England notes that its goal is "working to illustrate for everyone the importance of the sea, ships, time and the stars and their relationship with people." There is so much to explore in the "Sea and Ships" portion of the NMM website, but a great way to see everything it has to offer is by using the "Sea and Ships Directory" at the bottom of the homepage. It divides the material up by "Subjects", "People", "Collections", "Online Galleries", and "Games and Interactives". Visitors interested in lessons about the ocean that come in the form of games, quizzes and stories, should definitely check out the "Your Ocean" link from the "Games and Interactives". The "Your Waste" lesson gives visitors the opportunity to test their skills at "managing an oil spill clean-up operation", in the game "Oil Crisis!" Keeping waste to a minimum is what the quiz "Pollution Solutions" addresses, and is also on the "Your Waste" page. Other lessons include "Your Energy", "Your Stuff" and "Your Climate".

2010-05-04

430

Long Term Variability of Sea Surface Temperature in Mediterranean Sea  

NASA Astrophysics Data System (ADS)

The long term variability of the sea surface temperature (SST) of the Mediterranean basin and its sub-basins for the period 1869-2006 (138 years) is investigated using the International Comprehensive Ocean-Atmosphere Data Set (I-COADS). Analysis of the SST time-series revealed a positive trend in both basin and sub-basin scale. During the last century, the highest positive SST trend is found in the Adriatic Sea (0.0141° C/y) and the lowest one in the Aegean sea (0.0011° C/y). This difference in the SST evolution in the two sub-basins can be related to the shift of the Eastern Mediterranean deep water formation site during the 90s, known as Eastern Mediterranean Transient (EMT). The SST variations of the Eastern Mediterranean sub-basins (Adriatic Sea, Ionian Sea, Aegean Sea, Levantine Sea) are highly correlated to each other, in contrast to the poor correlation of the SST variations between the Eastern and Western Mediterranean Sea. Harmonic analysis has shown that a dominant period of the Mediterranean variability is similar to the deep water turnover time of the basin. Comparison with climatic indices points out a high correlation of the Western Mediterranean and Adriatic Sea SST with the NAO index, while the Eastern Mediterranean SST variations are highly correlated to the Indian Summer Monsoon Index.

Axaopoulos, P.; Sofianos, S.

2010-01-01

431

Light and vision in the deep-sea benthos: I. Bioluminescence at 500-1000 m depth in the Bahamian islands.  

PubMed

Bioluminescence is common and well studied in mesopelagic species. However, the extent of bioluminescence in benthic sites of similar depths is far less studied, although the relatively large eyes of benthic fish, crustaceans and cephalopods at bathyal depths suggest the presence of significant biogenic light. Using the Johnson-Sea-Link submersible, we collected numerous species of cnidarians, echinoderms, crustaceans, cephalopods and sponges, as well as one annelid from three sites in the northern Bahamas (500-1000 m depth). Using mechanical and chemical stimulation, we tested the collected species for light emission, and photographed and measured the spectra of the emitted light. In addition, in situ intensified video and still photos were taken of different benthic habitats. Surprisingly, bioluminescence in benthic animals at these sites was far less common than in mesopelagic animals from similar depths, with less than 20% of the collected species emitting light. Bioluminescent taxa comprised two species of anemone (Actinaria), a new genus and species of flabellate Parazoanthidae (formerly Gerardia sp.) (Zoanthidea), three sea pens (Pennatulacea), three bamboo corals (Alcyonacea), the chrysogorgiid coral Chrysogorgia desbonni (Alcyonacea), the caridean shrimp Parapandalus sp. and Heterocarpus ensifer (Decapoda), two holothuroids (Elasipodida and Aspidochirota) and the ophiuroid Ophiochiton ternispinus (Ophiurida). Except for the ophiuroid and the two shrimp, which emitted blue light (peak wavelengths 470 and 455 nm), all the species produced greener light than that measured in most mesopelagic taxa, with the emissions of the pennatulaceans being strongly shifted towards longer wavelengths. In situ observations suggested that bioluminescence associated with these sites was due primarily to light emitted by bioluminescent planktonic species as they struck filter feeders that extended into the water column. PMID:22956246

Johnsen, Sönke; Frank, Tamara M; Haddock, Steven H D; Widder, Edith A; Messing, Charles G

2012-10-01

432

Isotope studies in the Caspian Sea  

Microsoft Academic Search

Oceanographic and isotopic investigations in the Caspian Sea and the analyses of the available data on the discharge to the sea and the observed sea level changes suggest that climatically caused changes of river inflow are the major cause of the sea level fluctuations over the last century. Hydrogen-3 and 3H–3He data indicate that the deep basins of the sea

K. Froehlich; K. Rozanski; P. Povinec; B. Oregioni; J. Gastaud

1999-01-01

433

The USGS Salton Sea Science Office  

USGS Publications Warehouse

The U.S. Geological Survey's (USGS) Salton Sea Science Office (SSSO) provides scientific information and evaluations to decisionmakers who are engaged in restoration planning and actions associated with the Salton Sea. The primary focus is the natural resources of the Salton Sea, including the sea?s ability to sustain biological resources and associated social and economic values.

Case, Harvey Lee, III; Barnum, Douglas A.

2007-01-01

434

Sea Otter, River Otter. The Wonder Series.  

ERIC Educational Resources Information Center

This curriculum guide is all about otters and provides information on both sea and river otters. Included are activities related to the diet of sea otters, the adaptations sea otters have made to live in the sea, their tool-using abilities, where they live and how to spot them, comparative anatomy of sea and river otters, and otter movement. The…

Robinson, Sandra Chisholm

435

The Baltic Sea Basin: Introduction  

Microsoft Academic Search

\\u000a The Baltic Sea Basin serves as an example of a region where the use of natural resources and the need of environmental protection\\u000a require a comprehensive and holistic approach in terms of geosciences, environmental sciences, and socio-economics. In this\\u000a book, authors from countries around the Baltic Sea and overseas shed light on the Baltic Sea Basin with respect to (1)

Jan Harff; Svante Björck; Peer Hoth

436

Sea Scallop Shell Lab Handout  

NSDL National Science Digital Library

Used in combination with the Sea Scallop Shell Lab teacher's guide, students will examine sea scallop shells to figure out as much as possible about the scallops living on the sea floor in one three important fishery grounds, Hudson Canyon, off New Bedford, MA, and George's Bank. The activity emphasizes observation, measurements, and basic calculations. The teacher's guide is available from the COSEE-NE OSEI resource site.