20 research outputs found

    The bubble snails (Gastropoda, Heterobranchia) of Mozambique: an overlooked biodiversity hotspot

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    This first account, dedicated to the shallow water marine heterobranch gastropods of Mozambique is presented with a focus on the clades Acteonoidea and Cephalaspidea. Specimens were obtained as a result of sporadic sampling and two dedicated field campaigns between the years of 2012 and 2015, conducted along the northern and southern coasts of Mozambique. Specimens were collected by hand in the intertidal and subtidal reefs by snorkelling or SCUBA diving down to a depth of 33 m. Thirty-two species were found, of which 22 are new records to Mozambique and five are new for the Western Indian Ocean. This account raises the total number of shallow water Acteonoidea and Cephalaspidea known in Mozambique to 39 species, which represents approximately 50 % of the Indian Ocean diversity and 83 % of the diversity of these molluscs found in the Red Sea. A gap in sampling was identified in the central swamp/mangrove bio-region of Mozambique, and therefore, we suggest that future research efforts concentrate on or at least consider this region.publishedVersio

    The influence of surface charge on serum protein interaction and cellular uptake: studies with dendritic polyglycerols and dendritic polyglycerol-coated gold nanoparticles

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    Tony Bewersdorff,1 Jonathan Vonnemann,2 Asiye Kanik,1 Rainer Haag,2 Andrea Haase1 1Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Berlin, Germany; 2Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany Abstract: Nanoparticles (NPs) have gained huge interest in the medical field, in particular for drug delivery purposes. However, binding of proteins often leads to fast NP uptake and rapid clearance, thereby hampering medical applications. Thus, it is essential to determine and control the bio–nano interface. This study investigated the serum protein interactions of dendritic polyglycerols (dPGs), which are promising drug delivery candidates by means of two dimensional gel electrophoresis (2DE) in combination with mass spectrometry. In order to investigate the influence of surface charge, sulfated (sulfated dendritic polyglycerol [dPGS]) and non-sulfated (dPGOH) surfaces were applied, which were synthesized on a gold core allowing for easier separation from unbound biomolecules through centrifugation. Furthermore, two different sizes for dPGS were included. Although size had only a minor influence, considerable differences were detected in protein affinity for dPGS versus dPGOH surfaces, with dPGOH binding much less proteins. Cellular uptake into human CD14+ monocytes was analyzed by flow cytometry, and dPGOH was taken up to a much lower extent compared to dPGS. By using a pull-down approach, possible cellular interaction partners of serum pre-incubated dPGS-Au20 NPs from the membrane fraction of THP-1 cells could be identified such as for instance the transferrin receptor or an integrin. Clathrin-mediated endocytosis was further investigated using chlorpromazine as an inhibitor, which resulted in a 50% decrease of the cellular uptake of dPGS. This study could confirm the influence of surface charge on protein interactions and cellular uptake of dPGS. Furthermore, the approach allowed for the identification of possible uptake receptors and insights into the uptake mechanism. Keywords: sulfated dendritic polyglycerols, protein corona, cellular uptake, uptake receptors, clathrin-mediated endocytosi

    Polyglycerolsulfate functionalized gold nanorods as optoacoustic signal nanoamplifiers for <em>in vivo</em> bioimaging of rheumatoid arthritis.

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    We have synthesized a targeted imaging agent for rheumatoid arthritis based on polysulfated gold nanorods. The CTAB layer on gold nanorods was first replaced with PEG-thiol and then with dendritic polyglycerolsulfate at elevated temperature, which resulted in significantly reduced cytotoxicity compared to polyanionic gold nanorods functionalized by non-covalent approaches. In addition to classical characterization methods, we have established a facile UV-VIS based BaCl2 agglomeration assay to confirm a quantitative removal of unbound ligand. With the help of a competitive surface plasmon resonance-based L-selectin binding assay and a leukocyte adhesion-based flow cell assay, we have demonstrated the high inflammation targeting potential of the synthesized gold nanorods in vitro. In combination with the surface plasmon resonance band of AuNRs at 780 nm, these findings permitted the imaging of inflammation in an in vivo mouse model for rheumatoid arthritis with high contrast using multispectral optoacoustic tomography. The study offers a robust method for otherwise difficult to obtain covalently functionalized polyanionic gold nanorods, which are suitable for biological applications as well as a low-cost, actively targeted, and high contrast imaging agent for the diagnosis of rheumatoid arthritis. This paves the way for further research in other inflammation associated pathologies, in particular, when photothermal therapy can be applied

    Barcoding Antarctic biodiversity: current status and the CAML initiative, a case study of marine invertebrates.

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    The Census of Antarctic Marine Life (CAML) aims to collate DNA barcode data for Antarctic marine species. DNA barcoding is a technique that uses a short gene sequence from a standardised region of the genome as a diagnostic 'biomarker' for species. This study aimed to quantify genetic data currently available in GenBank in order to establish whether a representative cross-section of Antarctic marine taxa and bio-geographic areas has been sequenced and to propose priorities for barcoding, with a particular emphasis on marine invertebrate species. It was found that, amongst marine invertebrate fauna, sequence information covers a limited range of taxa and areas-mainly Crustacea, Annelida and Mollusca from the Weddell Sea and the Antarctic Peninsula. Only 15% of genes sequenced in Antarctic marine invertebrates were the standard barcode gene cytochrome c oxidase subunit 1 (CO1), the majority were other nuclear and mitochondrial genes. There is an urgent need for more in-depth genetic barcoding and species identification studies in Antarctic science, from a range of taxa and areas, given the rate of climate-driven habitat changes that might lead to extinctions in the region. CAML hopes to redress the balance, by collecting and sequencing over the circum-Antarctic area, using material from voyages that occurred during 2008 and 2009, within the framework of the International Polar Year (IPY)
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