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  • 1
    Keywords: Forschungsbericht ; Thermoelement
    Type of Medium: Online Resource
    Pages: 1 Online-Ressource (63 Seiten, 3,97 MB) , Illustrationen, Diagramme
    Language: German
    Note: Förderkennzeichen BMBF 03X3552G. - Verbund-Nummer 01084066 , "Laufzeit des Vorhabens: 01.05.2011 - 31.12.2014" - Rückseite der Titelseite , Unterschiede zwischen dem gedruckten Dokument und der elektronischen Ressource können nicht ausgeschlossen werden
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  • 2
    Keywords: Forschungsbericht
    Type of Medium: Online Resource
    Pages: Online-Ressource (33 S., 1,47 MB) , Ill., graph. Darst.
    Language: German
    Note: Förderkennzeichen BMBF 03IN2V5A. - Verbund-Nr. 01122925 , Unterschiede zwischen dem gedruckten Dokument und der elektronischen Ressource können nicht ausgeschlossen werden , Systemvoraussetzungen: Acrobat reader.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Oecologia 69 (1986), S. 628-630 
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary I assayed phenolic and tannin concentrations in a number of species of temperate and tropical brown algae of the genera Sargassum and Turbinaria. Tropical species in both genera contained consistently low levels of phenolics and tannins (species means ranged between 0 and 1.6% [measured as % dry weight of the thallus]). Levels of phenolics in temperate species of Sargassum were variable and consistently much higher than in tropical species (species means ranged between 3 and 12% by dry weight). This pattern of latitudinal variation in phenolic levels in Sargassum conflicts with previous predictions for latitudinal variation in the chemical defenses of marine organisms. The low levels of phenolics present in the tropical species that I analyzed may also explain recent results (Hay 1984; Lewis 1985) demonstrating that tropical Sargassum and Turbinaria are often preferentially consumed by herbivorous fishes and echinoids.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-1939
    Keywords: Brown algae ; Polyphenolics ; Chemical defenses ; Herbivory ; Biogeography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Polyphloroglucinol phenolics are the best known example of chemical deterrents against herbivores in temperate marine systems. However, most of the research on these compounds has been done in North America, where phenolic levels in algae are often low. I show here that algae in the Orders Fucales and Laminariales in temperate Australia and New Zealand typically contain very high levels of polyphenolics-much higher than species in these orders in North America. The median value for the distribution of mean phenolic levels for 25 North American species is 1.33% total phenolics (dry wt.); for 37 Australasian species, the median is 6.20%. Significant spatial, temporal, and intraplant variation in phenolic content occurs in a number of species in Australasia, but this does not significantly alter my major conclusion. Phenolic levels in drift algae (an important food source for some herbivores) detached for up to two weeks are also not significantly different from living, attached plants. Many species in the Fucales in Australasia also contain non-polyphenolic secondary metabolites that are not found in North American species. Thus herbivores in Australasia face greater amounts, and a greater range,of putative chemical defenses in brown algae than do herbivores in similar systems in North America. Any general theory for the evolution of marine plant/herbivore interactions must take into account such broad-scale biogeographical (and taxonomic) patterns.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Biodegradation 8 (1997), S. 211-220 
    ISSN: 1572-9729
    Keywords: antifouling ; homoserine lactones ; bacterial colonization ; biofilms ; furanones ; seaweeds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Any living or non-living surface immersed in seawaterrapidly acquires a bacterial biofilm. For living marineorganisms, biofilm formation can result in the death ofthe host, and thus there is strong evolutionary pressure formarine eukaryotes to evolve mechanisms which inhibit orcontrol the development of biofilms on their surfaces.Some marine eukaryotes are indeed successful incontrolling biofilms on their surfaces, and in manyinstances this control is achieved by the production ofinhibitory chemicals which act at or near the surface ofthe organism. In some cases these natural inhibitors aresimply toxic to bacteria. However, increasingly it appearsthat at least some of these compounds act by interferingspecifically with bacterial characteristics which effect theability of bacteria to colonize their hosts, such asattachment, surface spreading, or the production ofextracellular macromolecules. As an example, theAustralian seaweed Delisea pulchra appears tocontrol bacterial colonization by interfering with abacterial regulatory system (the acylated homoserinelactone system) that regulates several colonizationrelevant bacterial traits. Understanding how marineorganisms control specific bacterial colonization traitsshould provide us with insights into new technologies forthe control of biofilms on artificial surfaces.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 22 (1996), S. 1877-1899 
    ISSN: 1573-1561
    Keywords: Tannin-protein interaction ; tannins ; hydrogen bonding ; protein precipitation ; marine brown algae ; phlorotannins ; Carpophyllum maschalocarpum ; Ecklonia radiata ; Lobophora variegata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Tannins are one of the most broadly distributed types of plant secondary compounds, and have been the focal point for many studies of plant/herbivore interactions. Tannins interact strongly with proteins, so that the fate and effects of ingested tannins are in part dependent on the mode of interaction of the tannin with dietary and endogenous proteins in an herbivore's gut. We investigated the factors affecting the precipitation of proteins by phlorotannins from three species of marine brown algae:Carpophyllum maschalocarpum, Ecklonia radiata, andLobophora variegata. Phlorotannins were precipitated by proteins in a pH-dependent and concentration-dependent fashion. Precipitation also varied as a function of the presence of reducing agent, the type of phlorotannin or protein used, and the presence of organic solvents such as hydrogen bond inhibitors. Of particular significance was the ability of some phlorotannins to oxidize and form covalent bonds with some proteins. In contrast, under similar experimental conditions three types of terrestrial tannins (procyanidins, profisetinidins, and gallotannins) apparently did not form covalent complexes with proteins. Our results suggest several ways in which the biological activity of phlorotannins may vary as a function of the properties of the gut environment of marine herbivores. Moreover, we identify specific structural characteristics of phlorotannins which affect their tendency to oxidize, and thus, their potential effects on marine herbivores.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1573-1561
    Keywords: Phlorotannins ; DMBA ; Folin-Denis assay ; brown algae ; seaweeds ; phenolics ; PVPP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Quantitative measurement of phlorotannins (polyphenolics) in brown algae (Phaeophyta) by colorimetric assays can be confounded because: (1) most such assays also react to nonphlorotannin substances (interferences) and (2) the appropriate reference compound for such assays is not always clear, although phloroglucinol is typically used. We developed a new assay in which 2,4-dimethoxybenzaldehyde (DMBA) reacts specifically with 1,3-and 1,3,5-substituted phenols (e.g., phlorotannins) to form a colored product. This new assay, as well as eliminating the problem of measuring interferences, is inexpensive, rapid, and can be used with small sample volumes. We recommend it for all assays of phlorotannins from one or a set of closely related species where the structural types of phlorotannins present are likely to be similar among samples. It is also appropriate for broader surveys of phlorotannin levels across many species, but in this case a reference must be chosen with care. We also compared the DMBA assay to existing assays, including the Folin-Denis [both before and after the samples were mixed with polyvinylpolypyrrolidone (PVPP)] and the Prussian blue assays. PVPP was not 100% efficient (and often much less) at removing phlorotannins from solution, and its effectiveness varied among different phlorotannins. Thus, in contrast to previous studies, measuring phenolic levels in extracts before and after treatment with PVPP will not necessarily result in an interference-free measure of phlorotannins. Based on an analysis of reactive substances in red and green algae (which do not contain phlorotannins) in the Folin-Denis and Prussian blue assays, we estimate that the average level of interferences (nonphlorotannins) in brown algae measured in these two assays is on the order of 0.5% by dry weight.
    Type of Medium: Electronic Resource
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  • 8
    Publication Date: 2020-02-06
    Description: Our growing awareness of the microbial world’s importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about microbial life on Earth. Here we present a meta-analysis of microbial community samples collected by hundreds of researchers for the Earth Microbiome Project. Coordinated protocols and new analytical methods, particularly the use of exact sequences instead of clustered operational taxonomic units, enable bacterial and archaeal ribosomal RNA gene sequences to be followed across multiple studies and allow us to explore patterns of diversity at an unprecedented scale. The result is both a reference database giving global context to DNA sequence data and a framework for incorporating data from future studies, fostering increasingly complete characterization of Earth’s microbial diversity.
    Type: Article , PeerReviewed
    Format: text
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  • 9
    Publication Date: 2019-09-23
    Description: In many temperate regions, brown macroalgae fulfil essential ecosystem services such as the provision of structure, the fixation of nutrients and carbon, and the production of biomass and oxygen. Their populations in many regions around the globe have declined and/or spatially shifted in recent decades. In this review we highlight the potential global and regional drives of these changes, describe the status of regionally particularly important brown macroalgal species, and describe the capacity of interactions among abiotic and biotic factors to amplify or buffer environmental pressure on brown macroalgae. We conclude with a consideration of possible management and restoration measures.
    Type: Article , NonPeerReviewed
    Format: text
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  • 10
    Publication Date: 2015-09-26
    Description: The Journal of Physical Chemistry B DOI: 10.1021/acs.jpcb.5b06361
    Electronic ISSN: 1520-5207
    Topics: Chemistry and Pharmacology , Physics
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