@article{WolfBrandstetterBeutnerHessetal.2020,
  author    = {Wolf-Brandstetter, C and Beutner, R and Hess, R and Bierbaum, S and Wagner, K and Scharnweber, D and Gbureck, U and Moseke, C},
  title     = {Multifunctional calcium phosphate based coatings on titanium implants with integrated trace elements},
  series = {Biomedical Materials},
  volume    = {15},
  journal   = {Biomedical Materials},
  number    = {2},
  doi       = {10.1088/1748-605X/ab5d7b},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-254085},
  year      = {2020},
  abstract  = {For decades, the main focus of titanium implants developed to restore bone functionality was on improved osseointegration. Additional antimicrobial properties have now become desirable, due to the risk that rising antibiotic resistance poses for implant-associated infections. To this end, the trace elements of copper and zinc were integrated into calcium phosphate based coatings by electrochemically assisted deposition. In addition to their antimicrobial activity, zinc is reported to attract bone progenitor cells through chemotaxis and thus increase osteogenic differentiation, and copper to stimulate angiogenesis. Quantities of up to 68.9 ± 0.1 μg cm\(^{-2}\) of copper and 56.6 ± 0.4 μg cm\(^{-2}\) of zinc were deposited; co-deposition of both ions did not influence the amount of zinc but slightly increased the amount of copper in the coatings. The release of deposited copper and zinc species was negligible in serum-free simulated body fluid. In protein-containing solutions, a burst release of up to 10 μg ml\(^{-1}\) was observed for copper, while zinc was released continuously for up to 14 days. The presence of zinc was beneficial for adhesion and growth of human mesenchymal stromal cells in a concentration-dependent manner, but cytotoxic effects were already visible for coatings with an intermediate copper content. However, co-deposited zinc could somewhat alleviate the adverse effects of copper. Antimicrobial tests with E. coli revealed a decrease in adherent bacteria on brushite without copper or zinc of 60\%, but if the coating contained both ions there was almost no bacterial adhesion after 12 h. Coatings with high zinc content and intermediate copper content had the overall best multifunctional properties.},
  language  = {en}
}
@article{GrubbsSurupBiedermannetal.2020,
  author    = {Grubbs, Kirk J. and Surup, Frank and Biedermann, Peter H. W. and McDonald, Bradon R. and Klassen, Jonathan L. and Carlson, Caitlin M. and Clardy, Jon and Currie, Cameron R.},
  title     = {Cycloheximide-Producing Streptomyces Associated With Xyleborinus saxesenii and Xyleborus affinis Fungus-Farming Ambrosia Beetles},
  series = {Frontiers in Microbiology},
  volume    = {11},
  journal   = {Frontiers in Microbiology},
  doi       = {10.3389/fmicb.2020.562140},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-212449},
  year      = {2020},
  abstract  = {Symbiotic microbes help a myriad of insects acquire nutrients. Recent work suggests that insects also frequently associate with actinobacterial symbionts that produce molecules to help defend against parasites and predators. Here we explore a potential association between Actinobacteria and two species of fungus-farming ambrosia beetles, Xyleborinus saxesenii and Xyleborus affinis. We isolated and identified actinobacterial and fungal symbionts from laboratory reared nests, and characterized small molecules produced by the putative actinobacterial symbionts. One 16S rRNA phylotype of Streptomyces (XylebKG-1) was abundantly and consistently isolated from the galleries and adults of X. saxesenii and X. affinis nests. In addition to Raffaelea sulphurea, the symbiont that X. saxesenii cultivates, we also repeatedly isolated a strain of Nectria sp. that is an antagonist of this mutualism. Inhibition bioassays between Streptomyces griseus XylebKG-1 and the fungal symbionts from X. saxesenii revealed strong inhibitory activity of the actinobacterium toward the fungal antagonist Nectria sp. but not the fungal mutualist R. sulphurea. Bioassay guided HPLC fractionation of S. griseus XylebKG-1 culture extracts, followed by NMR and mass spectrometry, identified cycloheximide as the compound responsible for the observed growth inhibition. A biosynthetic gene cluster putatively encoding cycloheximide was also identified in S. griseus XylebKG-1. The consistent isolation of a single 16S phylotype of Streptomyces from two species of ambrosia beetles, and our finding that a representative isolate of this phylotype produces cycloheximide, which inhibits a parasite of the system but not the cultivated fungus, suggests that these actinobacteria may play defensive roles within these systems.},
  language  = {en}
}
@article{AzzamiRitterTautzetal.2012,
  author    = {Azzami, Klara and Ritter, Wolfgang and Tautz, J{\"u}rgen and Beier, Hildburg},
  title     = {Infection of honey bees with acute bee paralysis virus does not trigger humoral or cellular immune responses},
  series = {Archives of Virology},
  volume    = {157},
  journal   = {Archives of Virology},
  number    = {4},
  doi       = {10.1007/s00705-012-1223-0},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-126863},
  pages     = {689-702},
  year      = {2012},
  abstract  = {We have studied the responses of honey bees at different life stages (Apis mellifera) to controlled infection with acute bee paralysis virus and have identified the haemolymph of infected larvae and adult worker bees as the compartment where massive propagation of ABPV occurs. Insects respond with a broad spectrum of induced innate immune reactions to bacterial infections, whereas defence mechanisms based on RNA interference play a major role in antiviral immunity. In this study, we have determined that honey bee larvae and adult workers do not produce a humoral immune reaction upon artificial infection with ABPV, in contrast to control individuals challenged with Escherichia coli. ABPV-infected bees produced neither elevated levels of specific antimicrobial peptides (AMPs), such as hymenoptaecin and defensin, nor any general antimicrobial activity, as revealed by inhibition-zone assays. Additionally, adult bees did not generate melanised nodules upon ABPV infection, an important cellular immune function activated by bacteria and viruses in some insects. Challenge of bees with both ABPV and E. coli showed that innate humoral and cellular immune reactions are induced in mixed infections, albeit at a reduced level.},
  language  = {en}
}