305 research outputs found

    The marine myxosporean Sigmomyxa sphaerica (Thélohan, 1895) gen. n., comb. n. (syn. Myxidium sphaericum) from garfish (Belone belone (L.)) uses the polychaete Nereis pelagica L. as invertebrate host

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    Sigmomyxa sphaerica (Thélohan, 1892) gen. n. (Myxozoa, Myxosporea) with myxosporean stages in the gall bladder of Belone belone (L.) (Teleostei, Belonidae) uses the polychaete Nereis pelagica L. (Nereidae) from shallow water in the northern Øresund, Denmark, as invertebrate host. The nearly spherical tetractinomyxon-type actinospores of S. sphaerica differ from those of two species of Ellipsomyxa which also use Nereis spp. as invertebrate host. Pansporocysts of S. sphaerica were not seen. S. sphaerica is redescribed on the basis of myxospore stages from B. belone and actinospores from N. pelagica, and the phylogenetic affinities examined on the basis of ribosomal small subunit gene sequences. S. sphaerica is closest related to Ellipsomyxa spp., and is not congeneric with morphologically similar Myxidium spp. from gadids. This is the fifth elucidated two-host life cycle of a marine myxozoan

    Salinity dependence of parasite infestation in the European eel Anguilla anguilla in northern Germany

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    The aim of the study was to examine metazoan parasite communities of European eels (Anguilla anguilla) in fresh-water, brackish water and marine localities in northern Germany. In all, 29 parasite species/taxa were found in 170 eels: eight digeneans, one monogenean, five cestodes, ten nematodes, two acanthocephalans, and three crustaceans. Measures of diversity characteristics of the helminth communities included species richness, Shannon's diversity index and its evenness, and the Berger–Parker dominance index. The highest species diversity and lowest dominance values were calculated for the helminth communities of eels from the two Baltic Sea localities. Parasite communities of European eels clearly exhibit the habitat preferences of their hosts, salinity-dependent specificities, and a clustering into fresh-water, brackish, and marine groups. The highly pathogenic parasite species Anguillicola crassus and Pseudodactylogyrus spp. were found at all sampling sites in fresh water and brackish water, with high prevalence. Basic information is provided on the risks of restocking programmes solely focusing on fresh-water sites

    A review of the Zoogonidae (Digenea: Microphalloidea) from fishes of the waters around New Caledonia, with the description of Overstreetia cribbi n. sp.

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    New and published reports of zoogonid digeneans from New Caledonian waters are recorded, including a description of Overstreetia cribbi n. sp. from Atherinomorus lacunosus. This species differs from its congeners in the detail of its circum-oral spination and some metrical features. Other new records are of: Diphterostomum plectorhynchi Machida, Kamegai & Kuramochi, 2006 in Diagramma pictum; Parvipyrum acanthuri (Pritchard, 1963) in Acanthurus dussumieri; Zoogonoides viviparus (Olsson, 1868) in Lagocephalus sceleratus; Deretrema ? combesorum (Bray & Justine, 2008a; Bray & Justine, 2008b) early ovigerous forms in Parupeneus pleurostigma; D? acutum (Pritchard, 1963) in P. barberinus; and an unidentified immature zoogonid in P. multifasciatus. The newly reported specimens are illustrated and measurements given. The distribution of New Caledonian zoogonids is listed

    In vivo and in vitro synthesis of CM-proteins (A-hordeins) from barley (Hordeum vulgare L.)

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    CM-proteins from barley endosperm (CMa, CMb, CMc, CMd), which are the main components of the A-hordein fraction, are synthesized most actively 10 to 30 d after anthesis (maximum at 15–20 d). They are synthesized by membranebound polysomes as precursors of higher apparent molecular weight (13,000–21,000) than the mature proteins (12,000–16,000). The largest in vitro product (21,000) is the putative precursor of protein CMd (16,000), as it is selected with anti-CMd monospecific IgG's, and is coded by an mRNA of greater sedimentation coefficient (9 S) than those encoding the other three proteins (7.5 S). CM-proteins always appear in the soluble fraction, following different homogenization and subcellular fractionation procedures, indicating that these proteins are transferred to the soluble fraction after processing

    Status of Biodiversity in the Baltic Sea

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    The brackish Baltic Sea hosts species of various origins and environmental tolerances. These immigrated to the sea 10,000 to 15,000 years ago or have been introduced to the area over the relatively recent history of the system. The Baltic Sea has only one known endemic species. While information on some abiotic parameters extends back as long as five centuries and first quantitative snapshot data on biota (on exploited fish populations) originate generally from the same time, international coordination of research began in the early twentieth century. Continuous, annual Baltic Sea-wide long-term datasets on several organism groups (plankton, benthos, fish) are generally available since the mid-1950s. Based on a variety of available data sources (published papers, reports, grey literature, unpublished data), the Baltic Sea, incl. Kattegat, hosts altogether at least 6,065 species, including at least 1,700 phytoplankton, 442 phytobenthos, at least 1,199 zooplankton, at least 569 meiozoobenthos, 1,476 macrozoobenthos, at least 380 vertebrate parasites, about 200 fish, 3 seal, and 83 bird species. In general, but not in all organism groups, high sub-regional total species richness is associated with elevated salinity. Although in comparison with fully marine areas the Baltic Sea supports fewer species, several facets of the system's diversity remain underexplored to this day, such as micro-organisms, foraminiferans, meiobenthos and parasites. In the future, climate change and its interactions with multiple anthropogenic forcings are likely to have major impacts on the Baltic biodiversity
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