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  • 1
    Electronic Resource
    Electronic Resource
    Ökologie von Asterocheres lilljeborgi, eines auf Henricia sanguinolenta parasitisch lebenden Copepoden (1972)
    Springer
    Marine biology 13 (1972), S. 259-266 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung 1. Asterocheres lilljeborgi (Boeck, 1859) (Copepoda: Cyclopoida) wurde auf dem Seestern Henricia sanguinolenta aus dem Gullmarfjord beobachtet. 2. Copepodide, Männchen und Weibchen leben ektoparasitisch auf dem Seestern. Sie bleiben frei beweglich und besitzen in Körperform und Extremitätenbau keine speziellen Anpassungen an den Wirt. Als Nahrung dient Seesternepidermis, die extraintestinal vorverdaut und durch den birnenförmigen Sipho aufgenommen wird. 3. Der Mitteldarm von Asterocheres lilljeborgi besitzt Blindsäcke, die sich in der Reihenfolge Copepodid, Männchen, Weibchen zunehmend verzweigen. 4. Die Eizahl pro Eisack ist niedrig, sie beträgt 7 bis 9. 5. Bei der Begattung werden die Ventralseiten der Genitalsegmente beider Partner zusammengebracht und so die Spermatophoren übertragen. 6. Alle größeren H. sanguinolenta aus dem Gullmarfjord sind von A. lilljeborgi befallen. 7. Der Vergleich zwischen Scottomyzon gibberum und A. lilljeborgi ergibt, daß Scottomyzon-Weibchen in Körperbau und Verhalten stärker als Asterocheres-Weibchen abgewandelt sind.
    Notes: Abstract Living specimens of Asterocheres lilljeborgi (Boeck, 1859) (Copepoda: Cyclopoida) were observed on the sea star Henricia sanguinolenta from the Gullmarfjord, Sweden. Copepodid stages as well as males and females live ectoparasitically on the sea star. They maintain a motile way of life and do not posses special adaptations of body form and extremity structure to the echinoderm host. A. lilljeborgi digests the skin of H. sanguinolenta extra-intestinally and sucks up the food by means of the siphon-shaped mouth. The intestine has caeca, which become increasingly branched during the development from copepodid stages to male or to female. The number of eggs is low, 7 to 9 in each egg sack. During copulation, the ventral sides of the genital segments of both male and female approach each other closely, thus facilitating transfer of spermatophores. All larger H. sanguinolenta of the Gullmarfjord are infested by A. lilljeborgi. Comparison between Scottomyzon gibberum and A. lilljeborgi shows that the female of S. gibberum has become more modified in structure and behaviour than the A. lilljeborgi female. In order to characterize the degree of parasitic life of the two species (both Cyclopoida siphonostoma) the term “parasitic” (not “semiparasitic” or “associated”) is suggested, because the nauplius larvae only are free living.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00391383
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  • 2
    Electronic Resource
    Electronic Resource
    Der kammerbauvorgang der großforaminifere Heterostegina depressa (Nummulitidae) (1973)
    Springer
    Marine biology 18 (1973), S. 146-159 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung 1. Der Kammerbauvorgang der Großforaminifere Heterostegina depressa d'Orbigny 1826 (Nummulitidae) wurde an zahlreichen Individuen untersucht. Die Individuen waren bis zu einem halben Jahr alt und stammen aus Klonkulturen. 2. Der Kammerbauvorgang beginnt gewöhnlich zum Zeitpunkt des Lichtbeginns der Hell-Dunkelperiode. 3. Als erstes dreht sich das Tier in seiner festverankerten ektoplasmatischen Hülle, die es auf diese Weise dehnt. Es schafft damit den notwendigen Platz für die neue Kammer. 4. Gleichzeitig strömt Protoplasma aus dem Gehäuse und transportiert viele organische Partikel. 5. Nach 2 bis 3 Std lagern sich die organischen Partikel in einer 30 μm breiten Zone zwischen Gehäuserand und Ektoplasmahülle zu einer Schicht zusammen. 6. Im Laufe von weiteren 2 Std verengt sich diese Schicht und wird außen durch eine organische Membran scharf abgegrenzt. Organische Schicht und organische Membran markieren den Umriß der neuen Kammer samt Unterteilung in Kämmerchen. 7. In diese Kammeranlage fließt bereits Endoplasma mit den ersten symbiontischen Algen. 8. Nach Fertigstellung der organischen Membran beginnt deren Verkalkung und der Abbau der organischen Schicht. 9. Im Laufe der nächsten Stunden werden die Wände durch weitere Kalkanlagerung verstärkt, und die Ektoplasmahülle legt sich wieder an das Gehäuse. 10. Der Kammerbauvorgang dauert 24 Std.
    Notes: Abstract Chamber formation of Heterostegina depressa d'Orbigny 1826 mostly starts with the beginning of the daily light period. First, the necessary space for the construction of the new chamber (“Kammerhof”) is provided by rotation of the test inside the ectoplasm sheath, which is well fixed to the substrate. At the same time, protoplasm flows out of the aperture and out of the pores of the last chamber transporting organic particles. Three to 4 h after beginning of chamber formation, these particles coalesce to an organic layer between the ectoplasm sheath and the edge of the test. A short time later, this layer is bound on the outside by an organic membrane. Organic layer and organic membrane indicate the contour of the new chamber together with its chamberlets; they represent the “anlage” of the new chamber. Calcification takes place at this membrane. After the beginning of calcification, which lasts 15 to 20 h, the organic layer is removed and the ectoplasm sheath is retracted to the test.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00348689
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  • 3
    Electronic Resource
    Electronic Resource
    Light and Electron Microscopic Observations of Gametogenesis in Hastigerina pelagica (Foraminifera) (1978)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 25 (1978), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. During gametogenesis mother individuals of Hastigerina pelagica (d'Orbigny) undergo significant morphological changes. Thirty h before gamete release, the cytoplasm changes from pale orange to bright red, possibly due to transport of stored lipids from the inner region to more peripheral parts of the cytoplasm. During the next 10 to 15 h the bubble capsule which surounds the calcareous shell is discarded. After all bubbles have disappeared, the individual sheds its spines by resorbing the spine bases close to the shell surface.A single mother nucleus divides into some hundreds of thousands of gamete nuclei within a span of ∼ 20 h. A bulge of cytoplasm is extruded from the aperture and increases in size during the next 5 to 10 h. This bulge consists of cytoplasmic strands in which gametes and spherical bodies are embedded. The gametes and spherical bodies mature and are released during the afternoon and early evening. The gametes have 2 unequal acronematic flagella. A previously undescribed structure in foraminiferal reproduction is the spherical body which consists of a large vacuole surrounded by a thin cytoplasmic layer in which several nuclei, various typical cell organelles and multiple flagella are present. The spherical bodies are believed to play a role as receptacles of waste material, possibly including residual digestive enzymes, thereby protecting the gametes from lysis during the reproductive process. Fusion of gametes and further development into the next generation have not been observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1978.tb04164.x
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  • 4
    Electronic Resource
    Electronic Resource
    Formation and possible function of annulate lamellae in a planktic foraminifer
    Amsterdam : Elsevier
    Journal of Ultrasructure Research 81 (1982), S. 341-350 
    Details
    ISSN: 0022-5320
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/S0022-5320(82)90062-4
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  • 5
    Electronic Resource
    Electronic Resource
    Zur biogenese des aza-oxa-spiran-systems der steroidalkaloide vom spirosolan-typ in Solanaceen
    Amsterdam : Elsevier
    Phytochemistry 17 (1978), S. 251-255 
    Details
    ISSN: 0031-9422
    Keywords: S. laciniatum ; Solanaceae ; Solanum dulcamara ; biosynthesis ; soladulcidine ; solasodine ; steroidal alkaloids.
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/S0031-9422(00)94157-8
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  • 6
    Electronic Resource
    Electronic Resource
    The multiaxial creep ductility of austenitic stainless steels (2004)
    PO Box 1354, 9600 Garsington Road, Oxford OX4 2XG, UK. : Blackwell Science Ltd
    Fatigue & fracture of engineering materials & structures 27 (2004), S. 0 
    Details
    ISSN: 1460-2695
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Calculations of creep damage under conditions of strain control are often carried out using either a time fraction approach or a ductility exhaustion approach. In practice, calculations of creep damage are further complicated by the presence of multiaxial states of stress. In the case of the time fraction approach, there are a number of models that can be used to predict the effect of state of stress on creep rupture strength. In particular, Huddleston developed a model from data on stainless steels. The R5 procedure uses a ductility exhaustion approach to calculate creep damage and includes a model for use under triaxial states of stress. The aim of this paper is to describe the development of this model, which is based on considerations of cavity nucleation and growth and was developed from multiaxial creep data on Type 304 and 316 steels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-2695.2004.00732.x
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  • 7
    Electronic Resource
    Electronic Resource
    A Code of Practice for conducting notched bar creep tests and for interpreting the data (2004)
    PO Box 1354, 9600 Garsington Road, OxfordOX4 2XG, UK. : Blackwell Science Ltd
    Fatigue & fracture of engineering materials & structures 27 (2004), S. 0 
    Details
    ISSN: 1460-2695
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-2695.2004.00765.x
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  • 8
    Electronic Resource
    Electronic Resource
    Die Chemie der Insektizide, ihre Entwicklung und ihr heutiger Stand (1954)
    Springer
    Cellular and molecular life sciences 10 (1954), S. 91-131 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02158514
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  • 9
    Electronic Resource
    Electronic Resource
    On the structure and development of Arctic pack ice communities in Fram Strait: a multivariate approach (1992)
    Springer
    Polar biology 12 (1992), S. 727-733 
    Details
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The distribution of ice organisms was investigated in Fram Strait in May 1988 during the ARK V/1 expedition on RV Polarstern. Over a 3 week period the abundances of bacteria, diatoms, auto- and heterotrophic flagellates as well as various groups of meiofauna organisms were observed in the lowermost 30 cm of an ice floe. Data were obtained from three experimental fields under three different light regimes as a result of manipulations of the snow cover. The application of multivariate factor analysis on this time series data set resulted in the characterization of four succession stages of an Arctic sea ice community: 1) the diatom bottom assemblage, 2) the mixed autotrophic assemblage, 3) the mixed auto- and heterotrophic supra-bottom assemblage, and 4) the heterotrophic supra-bottom assemblage. The two most abundant meiofauna groups (Turbellaria, Ciliata) showed different preferences according to algal distribution. While turbellarians were most abundant in samples with mixed populations of diatoms and flagellates, ciliates reached their abundance maxima in samples dominated by diatoms, suggesting different prey selections. We have developed a model for the explanation of the spatial separation of auto- and heterotrophic organisms, highlighting the possible role of DOC production by ice algae and DOC transport with brine flow.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238874
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  • 10
    Electronic Resource
    Electronic Resource
    The role of the rock cod Notothenia coriiceps Richardson, 1844 in the life-cycle of Antarctic parasites (1998)
    Springer
    Polar biology 19 (1998), S. 399-406 
    Details
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Fifty specimens of Notothenia coriiceps caught in Potter Cove, King George Island, were examined for ecto- and endoparasites. Of the 22 parasite species found, 18 were helminths, 2 were hirudineans and 2 were crustaceans. The isopod Aega antarctica and an unidentified hirudinean are reported for the first time from this fish host. Dominant parasites were the adults of Aspersentis megarhynchus, the invasive stage of Corynosoma spp. (cystacanth) and the adults of Macvicaria pennelli, with respective prevalences of infestation of 94, 76 and 74%. The preferred sites of infestation were the pylorus and intestine, where five different larval (nematodes and cestodes) and eight adult (digeneans and acanthocephalans) parasite species were found. No adult nematodes and cestodes were found and no parasites could be isolated from the musculature. The results of the present study are related to previous findings on the parasite fauna of N. coriiceps. The comparison implies a high parasite diversity in this benthic Antarctic fish species. Most parasites found appear to have a wide range of distribution within Antarctic waters together with a low host specificity. Besides its role as final host for several species of trematodes and acanthocephalans, N. coriiceps serves as transmitter of parasite larvae to piscivorous birds and seals. It is concluded that the parasite fauna in Antarctic fish species provides important insights into the different habitat use and trophic relationship of their fish hosts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003000050265
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