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  • 1
    Electronic Resource
    Electronic Resource
    Chemical aspects of mass spawning in corals. I. Sperm-attractant molecules in the eggs of the scleractinian coral Montipora digitata (1994)
    Springer
    Marine biology 118 (1994), S. 177-182 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This paper provides the first evidence for sperm chemotaxis in the Scleractinia. Montipora digitata Dana, 1845 (Scleractinia: Coelenterata) is a hermaphroditic coral which reproduces bi-annually, releasing egg-sperm bundles during the mass spawning at Magnetic Island (19°10′S; 146°52′E) in late spring-early summer, and autumn each year. The buoyant egg-sperm bundles float to the surface where they break apart, releasing eggs and sperm into the ocean. Fertilisation occurs after ∼30 min. Unfertilized eggs were collected, washed free of sperm, and freeze-dried. The eggs were extracted with dichloromethane, fractionated by chromatography on silica gel, and the fractions assayed for their ability to attract M. digitata sperm. The active fraction was further fractionated by high-performance liquid chromatography, resulting in the isolation of three highly unsaturated fatty alcohols: (1) dodeca-2,4-diynol; (2) tetradec-13-ene-2,4-diynol; (3) (14Z)-heptadeca-14,16-diene-2,4-diynol. Of these three compounds, only Compound 1 attracted sperm of M. digitata. Synthetic Compound 1, produced from simple precursors by known reactions, possessed sperm-attracting activity comparable to the naturally derived attractant. Preliminary experiments suggest that the natural mixture of Compounds 1, 2 and 3 in the ratio 1:4:9 is more effective in attracting sperm from M. digitata than sperm from other Montipora species. Sperm attractants may act to reduce the incidence of hybridisation between different species of Montipora.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349783
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  • 2
    Electronic Resource
    Electronic Resource
    Chemical aspects of mass spawning in corals. II. (-)-Epi-thunbergol, the sperm attractant in the eggs of the soft coral Lobophytum crassum (Cnidaria: Octocorallia) (1995)
    Springer
    Marine biology 123 (1995), S. 137-143 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The eggs of Lobophytum crassum Von Marenzeller, 1886, collected at Magnetic Island (19°10′S; 146°52′E) in October or November between 1983 and 1993, contained significant amounts (6% dry weight) of (-)-epi-thunbergol, in addition to other terpenoid metabolites also present in the parent colony. (-)-Epi-thunbergol was not present in the tissues of the releasing colony. Using fluorocarbon droplets impregnated with the chemotactic molecules and a videomicroscopic technique for the direct observation of sperm under the influence of attractant molecules, we showed that (-)-epi-thunbergol, whether isolated from L. crassum or from a gorgonian octocoral (Briareum sp.), significantly attracts sperm from L. crassum colonies. Attraction could be detected using direct observation at concentrations as low as 3.25 μg ml-1. This is the first evidence for sperm chemotaxis in the Alcyonacea. Eggs from L compactum, a common alcyonacean coral at Orpheus Island (18°36′S; 146°29′E) contained (-)-thunbergol as the egg-specific compound. L. compactum was not found at Magnetic Island. (-)-Thunbergol from L. compactum and (+)-thunbergol from a Douglas fir tree both showed levels of attraction similar to (-)-epi-thunbergol against L. crassum sperm. Although L. crassum sperm were apparently neither stereo- nor enantio-specific in their selectivity for chemotactic molecules, (-)-epi-thunbergol was identified as the natural sperm attractant in the eggs of L. crassum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00350332
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  • 3
    Electronic Resource
    Electronic Resource
    (48) Systemic lupus erythematosus (1989)
    Oxford, UK : Blackwell Publishing Ltd
    British journal of dermatology 121 (1989), S. 0 
    Details
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2133.1989.tb06024.x
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  • 4
    Electronic Resource
    Electronic Resource
    The effect of spermine on the thermal denaturation profiles of ribosomal RNA and of ribosomes fromBacillus stearothermophilus in the presence of physiological concentrations of cations (1972)
    Springer
    Cellular and molecular life sciences 28 (1972), S. 785-787 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Zusammenfassung Nachweis, dass Spermin die rRNS vonB. stearothermophilus bei Thermaldenaturierung in Gegenwart physiologischer Konzentrationen von Kaliumund Magnesiumionen stabilisiert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01923129
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  • 5
    Electronic Resource
    Electronic Resource
    Structures and possible functions of epoxypukalide and pukalide (1989)
    Springer
    Journal of chemical ecology 15 (1989), S. 1177-1191 
    Details
    ISSN: 1573-1561
    Keywords: Sinularia spp. ; spawning ; soft coral ; pukalide ; epoxypukalide ; structure determination ; diterpene ; octocorals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Chemical analysis of the eggs spawned by fiveSinularia soft corals (Octocorallia, Alcyoniidae) collected in the central region of the Great Barrier Reef, Australia, revealed the presence of the known cembranoid diterpenes epoxypukalide and/or pukalide in all cases. Examination of the colonies from which the eggs were released one month before spawning and also some time after spawning failed to detect either diterpene in the coral tissue. The three dimensional structures of pukalide and epoxypukalide, as determined by the single-crystal X-ray technique, are reported for the first time. The wide distribution of pukalide and epoxypukalide and of related compounds within the octocorallia is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01014821
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  • 6
    Electronic Resource
    Electronic Resource
    Position of water in vitrified plants visualised by NMR imaging (1998)
    Springer
    Protoplasma 201 (1998), S. 110-114 
    Details
    ISSN: 1615-6102
    Keywords: Nuclear magnetic resonance imaging ; Plant tissue culture ; Vitrification ; Gypsophila paniculata ; Intercellular air spaces
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Vitrification of plants in vitro is a physiological abnormality of tissue-cultured plants which causes significant losses in the micropropagation industry. Vitrified plants are waterlogged but the position of water within plants has not been identified. Nuclear magnetic resonance (NMR) imaging of normal tissue-cultured, vitrified tissue-cultured, and glasshouse-grown leaves ofGypsophila paniculata showed the distribution of water within the leaves. Normal tissue-cultured and glasshouse-grown leaves had a high concentration of water within leaf vascular bundles and lower concentrations elsewhere. In contrast, vitrified leaves had a relatively even distribution of high water concentration throughout the leaves. When imaging parameters were changed, so that only water associated with cell membranes was shown, the images of normal tissue-cultured and glasshouse-grown leaves did not change. However, the image of the vitrified leaves showed a general lowering of intensity across the whole of the leaf. The appearance of the NMR images, together with those obtained by light microscopy, suggest that the excess water associated with vitrified plants is located in the intercellular air spaces. The blockage of these spaces may lead to a cycle of perturbations in the plant's physiology culminating in the development of vitrification.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01280717
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