3 research outputs found
New strategies in Bioconjugation : chemical modification of nucleic acids and peptides
No full textOne of the open challenges in chemical biology is to identify reactions that proceed with large rate constants in water at neutral pH values. Once assembled, these conjugates may be used for a broad variety of applications (e.g., therapeutics, imaging probes or as a catalytic system). Herein we describe a novel approach for the chemical modification of nucleic acids using guided organometallic-catalysts. Customized dirhodium complexes were prepared using modular ligands bearing various functional groups and connected to peptide nucleic acids through stable oxime linkages. The final constructs have been optimized for aqueous catalysis and were tested in preliminary alkylation studies of single-stranded DNA via dirhodium-carbenoids generated from alpha-diazocarbonyl compounds. During the course of optimizing the rather slow kinetics of oxime formation, we have developed two highly efficient methods for rapid oxime-based bioconjugations. (1) Dialdehydes were found to react with O-alkylhydroxylamines at rates of 500 M-1 s-1 in neutral aqueous buffer in the absence of a catalyst. The key to these conjugations is an unusually stable cyclic intermediate, which ultimately undergoes dehydration to yield an oxime. The scope and limitations of this method are outlined, as well as its application in bioconjugation with a DNA 41-mer and a mechanistic interpretation that will facilitate further developments of reactions with O-alkylhydroxylamines at low substrate concentrations. (2) Oximes proximal to boronic acids form in neutral aqueous buffer with rate constants of more than 104 M−1 s−1, the largest to date for any oxime condensation. The reaction tolerates a variety of biological interfering additives and is suitable for the rapid modification of short peptide sequences. Once formed, the oxime products are stable for days and undergo slow interconversion through a hydrolysis-based mechanism. Boron's dynamic coordination chemistry confers an adaptability that seems to aid a number of elementary steps in the oxime condensation.
In conclusion both methods represent important improvements for oxime-based bioconjugations in water (pH 7) at low equimolar concentrations. The high reaction kinetics are achieved without the need for additional reagents, catalysts or variations of the reaction conditions. In addition, the possibility of using reacting pairs that are commercially available will greatly enhance the applicability of these methods for efficient conjugations of precious biomolecules in the future
Arctic ecosystem services: challenges and opportunities (co-sponsored by AMAP, EU-PolarNet, and ICES)
No full textNo abstracts are to be cited without prior reference to the author.Conveners: Candace Nachman (USA), Susanne Kortsch (Norway).CM 2016/P:248. A Bioeconomic Model of Ocean Acidification Challenges in the Baffin Bay/Davis Straight Shrimp Fishery. Brooks A. Kaiser, Lars Ravn-JonsenCM 2016/P:122. An overview of the adequacy of Arctic sea basin data. Belinda J. Kater, Nathalie Steins, Martine J. van den Heuvel‐Greve, Peter Thijsse, CJ Beegle‐Krause, Oscar Bos, Bart Grasmeijer, Le Griffin, Eline van Onselen, Harriet van Overzee, Gerjan Piet, Andrea Sneekes, Arjan Tuijnder, Pepijn de Vries, Jan Tjalling van der WalCM 2016/P:624. Ballast water of domestic ships as a pathway for the introduction of non-indigenous mesozooplankton in coastal Nunavik, Canada. Pascal Tremblay, André Rochon, Gesche Winkler, Kimberly Howland, Nathalie Simard, Sarah BaileyCM 2016/P:445. Benthic non-indigenous species in ports of the Canadian Arctic: risks associated with global warming and shipping activity. Kimberly Howland, Jesica Goldsmit, Philippe Archambault, David Barber, Guillem Chust, George Liu, Jennifer Lukovich, Chris McKindsey, Ernesto VillarinoCM 2016/P:644. Climate change impacts on the ecosystem services of Arctic cod (Boreogadus saida). Benjamin J. Laurel, Louise A. CopemanCM 2016/P:178. Cod response to past and current warm phases in the seas of Iceland, a time series analysis. Marcos Llope, Niall McGinty, Joël Durant, Leif C. Stige, Guðrún Marteinsdóttir, Nils Chr. StensethCM 2016/P:450. Modelling spatio-temporal variation of surface hydrography in an Arctic shelf sea. Jussi Mäkinen, Jarno VanhataloCM 2016/P:129. Pink salmon as sentinels for climate change in the Arctic. Ed Farley, Wess Strasburger, Jeanette Gann, Kris CiecielCM 2016/P:433. Regional heterogeneity in climate change impacts on the living marine resources of the Arctic. Anne B. Hollowed, Wei Cheng, Harald Loeng, Libby Logerwell, Franz Mueter, James ReistCM 2016/P:268. Socio-economic impacts of ocean acidification and warming on Barents Sea Cod. Martina H. Stiasny, Martin Hänsel, Catriona Clemmesen, Flemming Dahlke, Felix H. Mittermayer, Martin Quaas, Thorsten Reusch, Daniela Storch, Rudi VossCM 2016/P:502. Structure and resilience of the benthic food web across the Canadian Arctic Ocean and the Chukchi sea. Noémie Friscourt, Christian Nozais, Philippe ArchambaultCM 2016/P:647. SYMBIOSES - a practical risk management tool to integrate fisheries and hydrocarbon activities in the Lofotens and Barents Sea, Norway. Daniel Howell, JoLynn Caroll, Frode VikebøCM 2016/P:405. The Missing Middle: The Need for International Collaboration to Fill Gaps in Central Arctic Ocean Science. Henry P. Huntington, Thomas Van Pelt, Hyoung Chul ShinCM 2016/P:280. Towards quantitative oil spill risk assessment in the Arctic sea areas. Maisa Nevalainen, Inari Helle, Jarno VanhataloCM 2016/P:556. Trophodynamics of Atlantic cod (Gadus morhua) on the Greenland continental shelf 2006-2010 and Spitsbergen 2010. Karl‐Michael Werner, Sophia Kochalski, Jerome Chladek, Corinna Schendel, Heino O. FockCM 2016/P:559. Unique insights from historical fisheries survey logbooks in the Arctic. John K. Pinnegar, Bryony L. Townhill, Georg H. Engelhard</p
PSA 009: Gendered Leader
No full textA Multi-Country Test of a Gender Fair Language Intervention for Stereotype Bia
