4 Material und Umwelt
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- 4 Material und Umwelt (231)
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Eingeladener Vortrag
- nein (97)
Technical advances in the study of molecular evolution have crystallized the fundamental insight that many bee pathogens evolve and adapt over timescales that overlap with host ecology. At the same time, the role played by bee host community ecology is increasingly being appreciated in host-parasite interactions. Here, we focus on Deformed wing virus (DWV) and present recent studies exploring the link between virulence, DWV genetic diversity and changes to host ecology - namely the arrival of an invasive ectoparasite, the Varroa destructor mite, which vectors viruses between honeybees. Specifically, we show how V. destructor may have created conditions for the emergence of more virulent strains of DWV in the western honeybee, Apis mellifera. We present a molecule-to-ecology framework to help interpret findings and to guide future hypotheses, emphasizing the role of molecular interactions between viruses and host immunity as drivers of change at the bee population level.
Bee populations have declined significantly in recent years and this is thought to be attributable at least in part to the (re-)emergence of viruses. These viruses are predominantly positive single stranded (+ss) RNA viruses belonging to the Picornavirales. Managed honeybees are often infested with the invasive mite, Varroa destructor, which vectors RNA viruses including Deformed wing virus (DWV, family Iflaviridae): a leading culprit of colony losses. Many bee viruses have been sequenced and structural features are now available for viruses such as DWV. DWV consists of at least 3 distinct genotypes, two of which have been shown to be differentially virulent in honeybees. Molecular studies have demonstrated that DWV has a mean evolutionary rate of 1.35 x 10-3 per site per year. For such viruses – in contrast to their eukaryotic hosts – ecological and evolutionary timescales significantly overlap. This rapid evolution allows RNA viruses to adapt quickly to novel host environments with recombination representing an additional key source of genetic variation. Interestingly, recombination between genotypes of DWV has recently been shown to be a common occurrence in honeybees. A challenge has been to develop bioinformatics tools that can accurately reconstruct viral haplotypes – including recombinants – from heterogenous high-throughput sequence data.
The impact of blood-to-blood Varroa destructor transmission on virus evolution represents an important question in bee virus research. Due to the nature of the V. destructor life cycle, predictions can be made about the potential impact of the mite on virus virulence evolution. Specifically, the developing honeybee host pupa should remain alive until close to the completion of metamorphosis to provide sufficient time for successful mite reproduction, including offspring mating. For optimal transmission, any virus found in a mature and mated daughter mite will hold a significant selective advantage over a virus found in an immature or unmated daughter mite – placing a cost on virus virulence that impacts honeybee pupae before mites can mate. On the other side, viruses replicating too slowly and with delayed virulence effects will hold a selective handicap because fewer transmission units will be found in mated mites. I have hypothesized that the evolution of virus virulence shifted following the arrival of V. destructor, with viruses, including recombinants and/or specific viral genotypes being selected for a level of virulence in pupae (and likely also in adults) that maximises R0, which represents the basic reproductive number of the virus in the host population. R0 is defined by the number of subsequent infections caused by a single infection and it must be greater than 1 for an infection to spread in a population. It is enhanced by maximising the number of transmission units passed to uninfected susceptible vectors, and ultimately hosts (Figure 1).
Honeybee viruses are also shared with sympatric wild bees and viral prevalence and sequence data indicate frequent virus transmission between managed and wild bee species. In addition to infecting the western honeybee (Apis mellifera), DWV can infect other Asian honeybee species such as Apis ceranae. Outside of honeybees, DWV has been found widely in bumblebees, including solitary bees and wasps and there is evidence that it can actively replicate in several Bombus and solitary bee species. Whether the arrival of the V. destructor mite in A. mellifera has driven viral emergence in non-Apis bees is a target of ongoing research.
Microbially influenced corrosion (MIC) of iron is usually attributed to sulfate-reducing microorganisms (SRM) which act upon the metal by the reactiveness of hydrogen sulfide, and by withdrawal of the available electrons in electrical contact with the metal. Methanogenic archaea can also cause MIC by directly withdrawing electrons from the iron surface for methanogenesis. However, the mechanistic details and kinetics of the overall process are poorly understood. Precipitation of siderite, a by-product of methanogenesis, (4Fe + 5HCO3 + 5H+ 4FeCO3 + CH4 + 3H2O) can lead to an insulating layer on the metal surface and lower the corrosion rate. Still, the extent of FeCO3 precipitation may be significantly influenced by environmental conditions such as pH and advective processes.
Wie Länder mit ihren Abfällen umgehen, hängt nicht nur von der Wirtschaftskraft eines Landes ab. Selbst in einem reichen Land wie Australien werden unbehandelte Abfälle einfach deponiert. Im Rahmen der Travelling Conference, einer vom Bundesministerium für Bildung und Forschung (BMBF) geförderten Vortragsreihe, besuchten Fachleute die Länder Südkorea, Vietnam und Australien, um mit Experten vor Ort Fragestellungen aus der Abfallwirtschaft zu diskutieren. Zu den Schwerpunktthemen zählte die Steigerung der Ressourceneffizienz im Spannungsfeld von ökonomischen und umweltpolitischen Interessen. Eine Frage war beispielsweise die Bewertung der Umweltverträglichkeit von mineralischen Abfällen, wenn diese als Ersatzbaustoffe eingesetzt werden. In diesem Beitrag werden Ähnlichkeiten und Unterschiede bei der Entsorgung von Siedlungsabfällen, beim Recycling und bei der Bewertung der Umweltverträglichkeit der Wiederverwertung von Abfällen in den drei besuchten Ländern im Vergleich zu Deutschland aufgezeigt. Dabei ist man sich in Deutschland und den drei besuchten Ländern einig, dass die Abfallbeseitigung auf Deponien ohne Rückgewinnung von Ressourcen oder Energie die schlechteste Abfallentsorgungsoption ist. Einigkeit besteht auch darin, dass die Ziele einer nachhaltigen Abfallwirtschaft der Schutz der menschlichen Gesundheit und der Umwelt sowie die Schonung von Ressourcen sind. In allen drei Ländern werden große Mengen an mineralischen Abfällen erzeugt, die bei Nachweis der Umweltverträglichkeit einen Teil von natürlichem Sand und Kies für die Bauindustrie ersetzen könnten. Ähnlich wie in Deutschland werden recycelte Abfälle im Tiefbau jedoch nur in geringem Maße eingesetzt. Gründe dafür sind fehlende Behandlungsanlagen für mineralische Abfälle und Bedenken im Hinblick auf die Umweltverträglichkeit.
A new sewage sludge ordinance was set in force in Germany in 2017 that makes phosphorus recovery from sewage sludge mandatory. The technological possibilities for P-recovery from waste water, sewage sludge and sewage sludge ash were presented.
Normativ ist der Holzschutz in Deutschland durch die DIN 68800-Reihe geregelt. Die Normungsarbeit in CEN/TC 38 bildet dafür den Rahmen, der national angepasst und fachspezifisch erweitert wurde. Zusammen mit dem Kommentar ergeben beide ein in Europa einzigartiges Regelkompendium im Holzschutz. In Zukunft wird die Regelsetzung noch stärker durch internationale Zusammenarbeit bestimmt sein. Der interkontinentalen Marktöffnung sollten Verständigungen auf gemeinsame Qualitätsstandards vorausgehen.
The Cairo Geniza is an “archive” discovered in the 19th century in Ben Ezra Synagogue in Fustat, a district in Old Cairo (Egypt). The collection of mostly Jewish documents that vary in genres, languages and writing supports contains a large number of early medieval Hebrew manuscripts.
The Geniza provides sources for the literary, linguistic, historical studies of the various aspects Jewish life. As the documents attest, at least two Jewish communities co-existed in Fustat up to 11th century: a so-called Babylonian and Palestinian. These communities had different leaders, different traditions and lived independently. The differences seem to manifest themselves also in the paleographical, codicological and some material properties of the manuscripts produced by each community.
The aim of this project is to compare the inks used in the Jewish documents depending on different variables: support (paper, parchment), purpose of the manuscript (legal, private, religious), provenance of the scribe. For the determination of the inks type and composition we had to choose non-invasive, non-destructive and portable techniques to analyze the corpus directly on-situ.
The analyses were carried out with a micro-X-ray spectrometer ArtTAX® (Bruker GmbH) and a digital stereomicroscope features built-in LED illumination at 395 nm and 940nm, Dino Lite.
We would like to stress that though the methods of material analysis listed above have been successfully employed in the field of cultural heritage and conservation including ancient and medieval manuscripts they have not yet been used to study fragments from the Cairo Genizah. Therefore, we believe that this research project is a pioneering study that will provide new insights into the history of Hebrew writing materials, their production techniques and materials and, thus, contribute new data to the field of Hebrew paleography.
L'archéométrie est une discipline riche qui peut nous apporter beaucoup d'informations sur l'étude des manuscrits et qui, conjuguée à la paléographie et la codicologie, peut s'apporter un outil précieux pour mieux appréhender les sociétés qui ont produits ces manuscrits.
Nous verrons ici quelques exemples de techniques scientifiques non destructives, principalement appliqués à la Génizah du Caire, appliquées à l'étude des manuscrits.