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  • 2015-2019  (24)
Schlagwörter
Erscheinungszeitraum
Jahr
  • 1
    Publikationsdatum: 2016-09-01
    Beschreibung: Resilin is an elastomeric protein typically occurring in exoskeletons of arthropods. It is composed of randomly orientated coiled polypeptide chains that are covalently cross-linked together at regular intervals by the two unusual amino acids dityrosine and trityrosine forming a stable network with a high degree of flexibility and mobility. As a result of its molecular prerequisites, resilin features exceptional rubber-like properties including a relatively low stiffness, a rather pronounced long-range deformability and a nearly perfect elastic recovery. Within the exoskeleton structures, resilin commonly forms composites together with other proteins and/or chitin fibres. In the last decades, numerous exoskeleton structures with large proportions of resilin and various resilin functions have been described. Today, resilin is known to be responsible for the generation of deformability and flexibility in membrane and joint systems, the storage of elastic energy in jumping and catapulting systems, the enhancement of adaptability to uneven surfaces in attachment and prey catching systems, the reduction of fatigue and damage in reproductive, folding and feeding systems and the sealing of wounds in a traumatic reproductive system. In addition, resilin is present in many compound eye lenses and is suggested to be a very suitable material for optical elements because of its transparency and amorphousness. The evolution of this remarkable functional diversity can be assumed to have only been possible because resilin exhibits a unique combination of different outstanding properties.
    Digitale ISSN: 2190-4286
    Thema: Chemie und Pharmazie , Maschinenbau , Physik , Technik allgemein
    Publiziert von Beilstein-Institut
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    Publikationsdatum: 2015-03-06
    Beschreibung: Copepods are dominant members of the marine zooplankton. Their diets often comprise large proportions of diatom taxa whose silicified frustules are mechanically stable and offer protection against grazers. Despite of this protection, many copepod species are able to efficiently break even the most stable frustule types. This ability requires specific feeding tools with mechanically adapted architectures, compositions and properties. When ingesting food, the copepods use the gnathobases of their mandibles to grab and, if necessary, crush and mince the food items. The morphology of these gnathobases is related to the diets of the copepods. Gnathobases of copepod species that mainly feed on phytoplankton feature compact and stable tooth-like structures, so-called teeth. In several copepod species these gnathobase teeth have been found to contain silica. Recent studies revealed that the siliceous teeth are complex microscale composites with silica-containing cap-like structures located on chitinous exoskeleton sockets that are connected with rubber-like bearings formed by structures with high proportions of the soft and elastic protein resilin. In addition, the silica-containing cap-like structures exhibit a nanoscale composite architecture. They contain some amorphous silica and large proportions of the crystalline silica type α-cristobalite and are pervaded by a fine chitinous fibre network that very likely serves as a scaffold during the silicification process. All these intricate composite structures are assumed to be the result of a coevolution between the copepod gnathobases and diatom frustules in an evolutionary arms race. The composites very likely increase both the performance of the siliceous teeth and their resistance to mechanical damage, and it is conceivable that their development has favoured the copepods’ dominance of the marine zooplankton observed today.
    Digitale ISSN: 2190-4286
    Thema: Chemie und Pharmazie , Maschinenbau , Physik , Technik allgemein
    Publiziert von Beilstein-Institut
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    Publikationsdatum: 2019-07-15
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
  • 5
  • 6
    Publikationsdatum: 2020-02-06
    Beschreibung: Gel particles—a class of abundant transparent organic particles—have increasingly gathered attention in marine research. Field studies on the bacterial colonization of marine gels however are still scarce. So far, most studies on respective particles have focused on the upper ocean, while little is known on their occurrence in the deep sea. Here, we report on the vertical distribution of the two most common gel particle types, which are polysaccharide-containing transparent exopolymer particles (TEP) and proteinaceous Coomassie stainable particles (CSP), as well as numbers of bacteria attached to gel particles throughout the water column, from the surface ocean down to the bathypelagial (〈 3,000 m). Our study was conducted in the Arctic Fram Strait during northern hemispheres' summer in 2015. Besides data on the bacterial colonization of the two gel particle types (TEP and CSP), we present bacterial densities on different gel particle size classes according to 12 different sampling depths at four sampling locations. Gel particles were frequently abundant at all sampled depths, and their concentrations decreased from the euphotic zone to the dark ocean. They were colonized by bacteria at all sampled water depths with risen importance at the deepest water layers, where fractions of bacteria attached to gel particles (%) increased within the total bacterial community. Due to the omnipresent bacterial colonization of gel particles at all sampled depths in our study, we presume that euphotic production of this type of organic matter may affect microbial species distribution within the whole water column in the Fram Strait, down to the deep sea. Our results raise the question if changes in the bacterial community composition and functioning on gel particles occur over depth, which may affect microbial respiration and remineralization rates of respective particles in different water layers.
    Materialart: Article , PeerReviewed
    Format: text
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    facet.materialart.
    Unbekannt
    In:  [Poster] In: ASLO Aquatic Sciences Meeting 2015, 22.-27.02.2015, Granada, Spain .
    Publikationsdatum: 2019-09-23
    Beschreibung: Although microplastics have dramatically accumulated in the marine environment, knowledge of their impact on organisms and biological processes in marine ecosystems is very scarce. The present study aimed at testing the hypothesis that microplastics participate in biogenic particle aggregation processes within the marine water column. For this purpose, interactions of polystyrene microplastics (700-900 µm) with biogenic particles, primarily phytoplankton, were investigated in laboratory experiments. Together with biogenic particles, microplastics formed relatively large aggregates. In the presence of microplastics, particle aggregation was faster and more pronounced compared to aggregation between biogenic particles only. At the end of the experiments, microplastics were covered by biofilms containing bacteria and microalgae. No aggregate formation took place in control experiments with microplastics and either filtered or artificial seawater. The aggregation of biogenic particles with biofilm-covered microplastics was much faster than that of biogenic particles with microplastics without biofilms. These results suggest that (1) microplastics interact with biogenic particles and are strongly involved in natural particle aggregation processes in the water column and (2) biofilm formation increases the microplastics’ aggregation potential.
    Materialart: Conference or Workshop Item , NonPeerReviewed
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    facet.materialart.
    Unbekannt
    Beilstein-Institut
    In:  Beilstein Journal of Nanotechnology, 6 (1). pp. 674-685.
    Publikationsdatum: 2017-04-13
    Beschreibung: Copepods are dominant members of the marine zooplankton. Their diets often comprise large proportions of diatom taxa whose silicified frustules are mechanically stable and offer protection against grazers. Despite of this protection, many copepod species are able to efficiently break even the most stable frustule types. This ability requires specific feeding tools with mechanically adapted architectures, compositions and properties. When ingesting food, the copepods use the gnathobases of their mandibles to grab and, if necessary, crush and mince the food items. The morphology of these gnathobases is related to the diets of the copepods. Gnathobases of copepod species that mainly feed on phytoplankton feature compact and stable tooth-like structures, so-called teeth. In several copepod species these gnathobase teeth have been found to contain silica. Recent studies revealed that the siliceous teeth are complex microscale composites with silica-containing cap-like structures located on chitinous exoskeleton sockets that are connected with rubber-like bearings formed by structures with high proportions of the soft and elastic protein resilin. In addition, the silica-containing cap-like structures exhibit a nanoscale composite architecture. They contain some amorphous silica and large proportions of the crystalline silica type α-cristobalite and are pervaded by a fine chitinous fibre network that very likely serves as a scaffold during the silicification process. All these intricate composite structures are assumed to be the result of a coevolution between the copepod gnathobases and diatom frustules in an evolutionary arms race. The composites very likely increase both the performance of the siliceous teeth and their resistance to mechanical damage, and it is conceivable that their development has favoured the copepods’ dominance of the marine zooplankton observed today.
    Materialart: Article , PeerReviewed
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 9
    facet.materialart.
    Unbekannt
    Elsevier
    In:  Zoology, 118 (3). pp. 141-146.
    Publikationsdatum: 2017-04-12
    Beschreibung: Copepods belong to the dominant marine zooplankton taxa and play an important role in particle and energy fluxes of the marine water column. Their mandibular gnathobases possess tooth-like structures, so-called teeth. In species feeding on large proportions of diatoms these teeth often contain silica, which is very probably the result of a coevolution with the siliceous diatom frustules. Detailed knowledge of the morphology and composition of the siliceous teeth is essential for understanding their functioning and their significance in the context of feeding interactions between copepods and diatoms. Based on analyses of the gnathobases of the Antarctic copepod Rhincalanus gigas, the present study clearly shows, for the first time, that the silica in the siliceous teeth features large proportions of crystalline silica that is consistent with the mineral α-cristobalite and is doped with aluminium. The siliceous structures have internal chitinous fibre networks, which are assumed to serve as scaffolds during the silicification process. The compact siliceous teeth of R. gigas are accompanied by structures with large proportions of the elastic protein resilin, likely reducing the mechanical damage of the teeth when the copepods feed on diatoms with very stable frustules. The results indicate that the coevolution with diatom frustules has resulted in gnathobases exhibiting highly sophisticated composite structures.
    Materialart: Article , PeerReviewed
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 10
    facet.materialart.
    Unbekannt
    The Royal Society
    In:  Interface: Journal of the Royal Society, 12 (104). p. 20141107.
    Publikationsdatum: 2017-09-28
    Beschreibung: Intergenomic evolutionary conflicts increase biological diversity. In sexual conflict, female defence against males is generally assumed to be resistance, which, however, often leads to trait exaggeration but not diversification. Here, we address whether tolerance, a female defence mechanism known from interspecific conflicts, exists in sexual conflict. We examined the traumatic insemination of female bed bugs via cuticle penetration by males, a textbook example of sexual conflict. Confocal laser scanning microscopy revealed large proportions of the soft and elastic protein resilin in the cuticle of the spermalege, the female defence organ. Reduced tissue damage and haemolymph loss were identified as adaptive female benefits from resilin. These did not arise from resistance because microindentation showed that the penetration force necessary to breach the cuticle was significantly lower at the resilin-rich spermalege than at other cuticle sites. Furthermore, a male survival analysis indicated that the spermalege did not impose antagonistic selection on males. Our findings suggest that the specific spermalege material composition evolved to tolerate the traumatic cuticle penetration. They demonstrate the importance of tolerance in sexual conflict and genitalia evolution, extend fundamental coevolution and speciation models and contribute to explaining the evolution of complexity. We propose that tolerance can drive trait diversity.
    Materialart: Article , PeerReviewed
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
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