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Frederiksen A, Aldag M, Solov’yov IA, Gerhards L. Activation of Cryptochrome 4 from Atlantic Herring. Biology (Basel) 2024; 13:262. [PMID: 38666874 PMCID: PMC11048568 DOI: 10.3390/biology13040262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 04/04/2024] [Accepted: 04/11/2024] [Indexed: 04/28/2024]
Abstract
Marine fish migrate long distances up to hundreds or even thousands of kilometers for various reasons that include seasonal dependencies, feeding, or reproduction. The ability to perceive the geomagnetic field, called magnetoreception, is one of the many mechanisms allowing some fish to navigate reliably in the aquatic realm. While it is believed that the photoreceptor protein cryptochrome 4 (Cry4) is the key component for the radical pair-based magnetoreception mechanism in night migratory songbirds, the Cry4 mechanism in fish is still largely unexplored. The present study aims to investigate properties of the fish Cry4 protein in order to understand the potential involvement in a radical pair-based magnetoreception. Specifically, a computationally reconstructed atomistic model of Cry4 from the Atlantic herring (Clupea harengus) was studied employing classical molecular dynamics (MD) and quantum mechanics/molecular mechanics (QM/MM) methods to investigate internal electron transfers and the radical pair formation. The QM/MM simulations reveal that electron transfers occur similarly to those found experimentally and computationally in Cry4 from European robin (Erithacus rubecula). It is therefore plausible that the investigated Atlantic herring Cry4 has the physical and chemical properties to form radical pairs that in turn could provide fish with a radical pair-based magnetic field compass sensor.
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Affiliation(s)
- Anders Frederiksen
- Institute of Physics, Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky Straße 9-11, 26129 Oldenburg, Germany; (A.F.); (M.A.); (I.A.S.)
| | - Mandus Aldag
- Institute of Physics, Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky Straße 9-11, 26129 Oldenburg, Germany; (A.F.); (M.A.); (I.A.S.)
| | - Ilia A. Solov’yov
- Institute of Physics, Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky Straße 9-11, 26129 Oldenburg, Germany; (A.F.); (M.A.); (I.A.S.)
- Research Centre for Neurosensory Sciences, Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky Straße 9-11, 26129 Oldenburg, Germany
- Center for Nanoscale Dynamics (CENAD), Carl von Ossietzky University of Oldenburg, Ammerländer Heerstr. 114-118, 26129 Oldenburg, Germany
| | - Luca Gerhards
- Institute of Physics, Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky Straße 9-11, 26129 Oldenburg, Germany; (A.F.); (M.A.); (I.A.S.)
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2
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Langebrake C, Manthey G, Frederiksen A, Lugo Ramos JS, Dutheil JY, Chetverikova R, Solov'yov IA, Mouritsen H, Liedvogel M. Adaptive evolution and loss of a putative magnetoreceptor in passerines. Proc Biol Sci 2024; 291:20232308. [PMID: 38320616 PMCID: PMC10846946 DOI: 10.1098/rspb.2023.2308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 01/08/2024] [Indexed: 02/08/2024] Open
Abstract
Migratory birds possess remarkable accuracy in orientation and navigation, which involves various compass systems including the magnetic compass. Identifying the primary magnetosensor remains a fundamental open question. Cryptochromes (Cry) have been shown to be magnetically sensitive, and Cry4a from a migratory songbird seems to show enhanced magnetic sensitivity in vitro compared to Cry4a from resident species. We investigate Cry and their potential involvement in magnetoreception in a phylogenetic framework, integrating molecular evolutionary analyses with protein dynamics modelling. Our analysis is based on 363 bird genomes and identifies different selection regimes in passerines. We show that Cry4a is characterized by strong positive selection and high variability, typical characteristics of sensor proteins. We identify key sites that are likely to have facilitated the evolution of an optimized sensory protein for night-time orientation in songbirds. Additionally, we show that Cry4 was lost in hummingbirds, parrots and Tyranni (Suboscines), and thus identified a gene deletion, which might facilitate testing the function of Cry4a in birds. In contrast, the other avian Cry (Cry1 and Cry2) were highly conserved across all species, indicating basal, non-sensory functions. Our results support a specialization or functional differentiation of Cry4 in songbirds which could be magnetosensation.
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Affiliation(s)
- Corinna Langebrake
- Institute of Avian Research ‘Vogelwarte Helgoland’, 26386 Wilhelmshaven, Germany
- MPRG Behavioural Genomics, MPI Evolutionary Biology, 24306 Plön, Germany
| | - Georg Manthey
- Institute of Avian Research ‘Vogelwarte Helgoland’, 26386 Wilhelmshaven, Germany
- Department of Physics, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg
| | - Anders Frederiksen
- Department of Physics, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg
| | - Juan S. Lugo Ramos
- MPRG Behavioural Genomics, MPI Evolutionary Biology, 24306 Plön, Germany
- The Francis Crick Institute, London NW1 1AT, UK
| | - Julien Y. Dutheil
- Research Group Molecular Systems Evolution, MPI Evolutionary Biology, 24306 Plön, Germany
| | - Raisa Chetverikova
- Biology and Environmental Sciences Department, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg
| | - Ilia A. Solov'yov
- Department of Physics, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg
- Research Centre for Neurosensory Sciences, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg
- Center for Nanoscale Dynamics (CENAD), Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg
| | - Henrik Mouritsen
- Biology and Environmental Sciences Department, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg
- Research Centre for Neurosensory Sciences, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg
| | - Miriam Liedvogel
- Institute of Avian Research ‘Vogelwarte Helgoland’, 26386 Wilhelmshaven, Germany
- MPRG Behavioural Genomics, MPI Evolutionary Biology, 24306 Plön, Germany
- Biology and Environmental Sciences Department, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg
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3
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Frederiksen A, Langebrake C, Hanić M, Manthey G, Mouritsen H, Liedvogel M, Solov’yov IA. Mutational Study of the Tryptophan Tetrad Important for Electron Transfer in European Robin Cryptochrome 4a. ACS Omega 2023; 8:26425-26436. [PMID: 37521624 PMCID: PMC10373462 DOI: 10.1021/acsomega.3c02963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Accepted: 06/23/2023] [Indexed: 08/01/2023]
Abstract
The ability of migratory birds to sense magnetic fields has been known for decades, although the understanding of the underlying mechanism is still elusive. Currently, the strongest magnetoreceptor candidate in birds is a protein called cryptochrome 4a. The cryptochrome 4a protein has changed through evolution, apparently endowing some birds with a more pronounced magnetic sensitivity than others. Using phylogenetic tools, we show that a specific tryptophan tetrad and a tyrosine residue predicted to be essential for cryptochrome activation are highly conserved in the avian clade. Through state-of-the-art molecular dynamics simulations and associated analyses, we also studied the role of these specific residues and the associated mutants on the overall dynamics of the protein. The analyses of the single residue mutations were used to judge how far a local change in the protein structure can impact specific dynamics of European robin cryptochrome 4a. We conclude that the replacements of each of the tryptophans one by one with a phenylalanine do not compromise the overall stability of the protein.
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Affiliation(s)
- Anders Frederiksen
- Institute
of Physics, Carl von Ossietzky Universität
Oldenburg, Carl-von-Ossietzky Strasse 9-11, Oldenburg 26129, Germany
| | - Corinna Langebrake
- Institute
of Avian Research, An der Vogelwarte 21, Wilhelmshaven 26386, Germany
| | - Maja Hanić
- Institute
of Physics, Carl von Ossietzky Universität
Oldenburg, Carl-von-Ossietzky Strasse 9-11, Oldenburg 26129, Germany
| | - Georg Manthey
- Institute
of Physics, Carl von Ossietzky Universität
Oldenburg, Carl-von-Ossietzky Strasse 9-11, Oldenburg 26129, Germany
- Institute
of Avian Research, An der Vogelwarte 21, Wilhelmshaven 26386, Germany
| | - Henrik Mouritsen
- Department
of Biology and Environmental Sciences, Carl
von Ossietzky University of Oldenburg, Carl-von-Ossietzky Strasse 9-11, Oldenburg 26129, Germany
- Research
Centre for Neurosensory Sciences, Carl von
Ossietzky University of Oldenburg, Carl-von-Ossietzky Strasse 9-11, Oldenburg 26129, Germany
| | - Miriam Liedvogel
- Institute
of Avian Research, An der Vogelwarte 21, Wilhelmshaven 26386, Germany
- Department
of Biology and Environmental Sciences, Carl
von Ossietzky University of Oldenburg, Carl-von-Ossietzky Strasse 9-11, Oldenburg 26129, Germany
- MPRG
Behavioural Genomics, Max Planck Institute
for Evolutionary Biology, August-Thienemann-Str. 2, Plön 24306, Germany
| | - Ilia A. Solov’yov
- Institute
of Physics, Carl von Ossietzky Universität
Oldenburg, Carl-von-Ossietzky Strasse 9-11, Oldenburg 26129, Germany
- Research
Centre for Neurosensory Sciences, Carl von
Ossietzky University of Oldenburg, Carl-von-Ossietzky Strasse 9-11, Oldenburg 26129, Germany
- Department
of Physics, Center for Nanoscale Dynamics (CENAD), Carl von Ossietzky University of Oldenburg, Ammerländer Heerstr. 114-118, Oldenburg 26129, Germany
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4
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Timmer D, Frederiksen A, Lünemann DC, Thomas AR, Xu J, Bartölke R, Schmidt J, Kubař T, De Sio A, Solov'yov IA, Mouritsen H, Lienau C. Tracking the Electron Transfer Cascade in European Robin Cryptochrome 4 Mutants. J Am Chem Soc 2023; 145:11566-11578. [PMID: 37195086 DOI: 10.1021/jacs.3c00442] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The primary step in the mechanism by which migratory birds sense the Earth's magnetic field is thought to be the light-induced formation of long-lived magnetically sensitive radical pairs within cryptochrome flavoproteins located in the birds' retinas. Blue-light absorption by the non-covalently bound flavin chromophore triggers sequential electron transfers along a chain of four tryptophan residues toward the photoexcited flavin. The recently demonstrated ability to express cryptochrome 4a from the night-migratory European robin (Erithacus rubecula), ErCry4a, and to replace each of the tryptophan residues by a redox-inactive phenylalanine offers the prospect of exploring the roles of the four tryptophans. Here, we use ultrafast transient absorption spectroscopy to compare wild type ErCry4a and four mutants having a phenylalanine at different positions in the chain. We find that each of the three tryptophan residues closest to the flavin adds a distinct relaxation component (time constants: 0.5, 30, and 150 ps) in the transient absorption data. The dynamics of the mutant containing a phenylalanine at the fourth position, furthest from the flavin, are very similar to those of wild type ErCry4a, except for a reduced concentration of long-lived radical pairs. The experimental results are evaluated and discussed in the framework of real-time quantum mechanical/molecular mechanical electron transfer simulations based on the density functional-based tight binding approach. This comparison between simulation results and experimental measurements provides a detailed microscopic insight into the sequential electron transfers along the tryptophan chain. Our results offer a route to the study of spin transport and dynamical spin correlations in flavoprotein radical pairs.
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Affiliation(s)
- Daniel Timmer
- Institut für Physik, Carl von Ossietzky Universität, 26129 Oldenburg, Germany
| | - Anders Frederiksen
- Institut für Physik, Carl von Ossietzky Universität, 26129 Oldenburg, Germany
| | - Daniel C Lünemann
- Institut für Physik, Carl von Ossietzky Universität, 26129 Oldenburg, Germany
| | - Anitta R Thomas
- Institut für Physik, Carl von Ossietzky Universität, 26129 Oldenburg, Germany
| | - Jingjing Xu
- Institut für Biologie und Umweltwissenschaften, Carl von Ossietzky Universität, 26129 Oldenburg, Germany
| | - Rabea Bartölke
- Institut für Biologie und Umweltwissenschaften, Carl von Ossietzky Universität, 26129 Oldenburg, Germany
| | - Jessica Schmidt
- Institut für Biologie und Umweltwissenschaften, Carl von Ossietzky Universität, 26129 Oldenburg, Germany
| | - Tomáš Kubař
- Department for Theoretical Chemical Biology, Institute for Physical Chemistry, Karlsruhe Institute of Technology, Kaiserstrasse 12, 76131 Karlsruhe, Germany
| | - Antonietta De Sio
- Institut für Physik, Carl von Ossietzky Universität, 26129 Oldenburg, Germany
- Center for Nanoscale Dynamics (CENAD), Carl von Ossietzky Universität Oldenburg, Institut für Physik, 26129 Oldenburg, Germany
| | - Ilia A Solov'yov
- Institut für Physik, Carl von Ossietzky Universität, 26129 Oldenburg, Germany
- Research Centre for Neurosensory Science, Carl von Ossietzky Universität, 26111 Oldenburg, Germany
- Center for Nanoscale Dynamics (CENAD), Carl von Ossietzky Universität Oldenburg, Institut für Physik, 26129 Oldenburg, Germany
| | - Henrik Mouritsen
- Institut für Biologie und Umweltwissenschaften, Carl von Ossietzky Universität, 26129 Oldenburg, Germany
- Research Centre for Neurosensory Science, Carl von Ossietzky Universität, 26111 Oldenburg, Germany
| | - Christoph Lienau
- Institut für Physik, Carl von Ossietzky Universität, 26129 Oldenburg, Germany
- Research Centre for Neurosensory Science, Carl von Ossietzky Universität, 26111 Oldenburg, Germany
- Center for Nanoscale Dynamics (CENAD), Carl von Ossietzky Universität Oldenburg, Institut für Physik, 26129 Oldenburg, Germany
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5
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Hanić M, Schuhmann F, Frederiksen A, Langebrake C, Manthey G, Liedvogel M, Xu J, Mouritsen H, Solov'yov IA. Computational Reconstruction and Analysis of Structural Models of Avian Cryptochrome 4. J Phys Chem B 2022; 126:4623-4635. [PMID: 35704801 DOI: 10.1021/acs.jpcb.2c00878] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A recent study by Xu et al. (Nature, 2021, 594, 535-540) provided strong evidence that cryptochrome 4 (Cry4) is a key protein to endow migratory birds with the magnetic compass sense. The investigation compared the magnetic field response of Cry4 from migratory and nonmigratory bird species and suggested that a difference in magnetic sensitivity could exist. This finding prompted an in-depth investigation into Cry4 protein differences on the structural and dynamic levels. In the present study, the pigeon Cry4 (ClCry4) crystal structure was used to reconstruct the missing avian Cry4 protein structures via homology modeling for carefully selected bird species. The reconstructed Cry4 structure from European robin, Eurasian blackcap, zebra finch, chicken, and pigeon were subsequently simulated dynamically and analyzed. The studied avian Cry4 structures show flexibility in analogous regions pointing to similar activation mechanisms and/or signaling interaction partners. It can be concluded that the experimentally recorded difference in the magnetic field sensitivity of Cry4 from different birds is unlikely to be due to solely intrinsic dynamics of the proteins but requires additional factors that have not yet been identified.
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Affiliation(s)
- Maja Hanić
- Department of Physics, Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky Straße 9-11, Oldenburg 26129, Germany
| | - Fabian Schuhmann
- Department of Physics, Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky Straße 9-11, Oldenburg 26129, Germany
| | - Anders Frederiksen
- Department of Physics, Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky Straße 9-11, Oldenburg 26129, Germany
| | - Corinna Langebrake
- Institute of Avian Research, An der Vogelwarte 21, Wilhelmshaven 26386, Germany
| | - Georg Manthey
- Department of Physics, Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky Straße 9-11, Oldenburg 26129, Germany.,Institute of Avian Research, An der Vogelwarte 21, Wilhelmshaven 26386, Germany
| | - Miriam Liedvogel
- Institute of Avian Research, An der Vogelwarte 21, Wilhelmshaven 26386, Germany.,Department of Biology and Environmental Sciences, Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky Straße 9-11, Oldenburg 26129, Germany.,MPRG Behavioural Genomics, Max Planck Institute for Evolutionary Biology, Plön 24306, Germany
| | - Jingjing Xu
- Department of Biology and Environmental Sciences, Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky Straße 9-11, Oldenburg 26129, Germany
| | - Henrik Mouritsen
- Department of Biology and Environmental Sciences, Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky Straße 9-11, Oldenburg 26129, Germany.,Research Center for Neurosensory Sciences, Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky Straße 9-11, Oldenburg 26129, Germany
| | - Ilia A Solov'yov
- Department of Physics, Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky Straße 9-11, Oldenburg 26129, Germany.,Research Center for Neurosensory Sciences, Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky Straße 9-11, Oldenburg 26129, Germany.,Center for Nanoscale Dynamics (CENAD), Carl von Ossietzky Universität Oldenburg, Institut für Physik, Ammerländer Heerstr. 114-118, 26129 Oldenburg, Germany
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Korol V, Husen P, Sjulstok E, Nielsen C, Friis I, Frederiksen A, Salo AB, Solov’yov IA. Introducing VIKING: A Novel Online Platform for Multiscale Modeling. ACS Omega 2020; 5:1254-1260. [PMID: 31984283 PMCID: PMC6977254 DOI: 10.1021/acsomega.9b03802] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 11/29/2019] [Indexed: 05/17/2023]
Abstract
Various biochemical and biophysical processes, occurring on multiple time and length scales, can nowadays be studied using specialized software packages on supercomputer clusters. The complexity of such simulations often requires application of different methods in a single study and strong computational expertise. We have developed VIKING, a convenient web platform for carrying out multiscale computations on supercomputers. VIKING allows combining methods in standardized workflows, making complex simulations accessible to a broader biochemical and biophysical society.
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Affiliation(s)
- Vasili Korol
- Department
of Physics, Chemistry and Pharmacy, University
of Southern Denmark, Odense 5230, Denmark
| | - Peter Husen
- Department
of Physics, Chemistry and Pharmacy, University
of Southern Denmark, Odense 5230, Denmark
| | - Emil Sjulstok
- Department
of Physics, Chemistry and Pharmacy, University
of Southern Denmark, Odense 5230, Denmark
- Neuroscience, University of Texas Southwestern Medical Center at
Dallas, Dallas 75390, Texas, United States
| | - Claus Nielsen
- Department
of Physics, Chemistry and Pharmacy, University
of Southern Denmark, Odense 5230, Denmark
| | - Ida Friis
- Department
of Physics, Chemistry and Pharmacy, University
of Southern Denmark, Odense 5230, Denmark
| | - Anders Frederiksen
- Department
of Physics, Chemistry and Pharmacy, University
of Southern Denmark, Odense 5230, Denmark
| | - Adrian B. Salo
- Department
of Physics, Chemistry and Pharmacy, University
of Southern Denmark, Odense 5230, Denmark
| | - Ilia A. Solov’yov
- Department
of Physics, Chemistry and Pharmacy, University
of Southern Denmark, Odense 5230, Denmark
- Department
of Physics, Carl von Ossietzky Universität
Oldenburg, Oldenburg 26111, Germany
- E-mail:
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7
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Frahs S, Reeck JC, Yocham KM, Frederiksen A, Fujimoto K, Scott CM, Beard RS, Brown RJ, Lujan TJ, Solov’yov IA, Estrada D, Oxford JT. Prechondrogenic ATDC5 Cell Attachment and Differentiation on Graphene Foam; Modulation by Surface Functionalization with Fibronectin. ACS Appl Mater Interfaces 2019; 11:41906-41924. [PMID: 31639302 PMCID: PMC6858527 DOI: 10.1021/acsami.9b14670] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 10/22/2019] [Indexed: 05/25/2023]
Abstract
Graphene foam holds promise for tissue engineering applications. In this study, graphene foam was used as a three-dimension scaffold to evaluate cell attachment, cell morphology, and molecular markers of early differentiation. The aim of this study was to determine if cell attachment and elaboration of an extracellular matrix would be modulated by functionalization of graphene foam with fibronectin, an extracellular matrix protein that cells adhere well to, prior to the establishment of three-dimensional cell culture. The molecular dynamic simulation demonstrated that the fibronectin-graphene interaction was stabilized predominantly through interaction between the graphene and arginine side chains of the protein. Quasi-static and dynamic mechanical testing indicated that fibronectin functionalization of graphene altered the mechanical properties of graphene foam. The elastic strength of the scaffold increased due to fibronectin, but the viscoelastic mechanical behavior remained unchanged. An additive effect was observed in the mechanical stiffness when the graphene foam was both coated with fibronectin and cultured with cells for 28 days. Cytoskeletal organization assessed by fluorescence microscopy demonstrated a fibronectin-dependent reorganization of the actin cytoskeleton and an increase in actin stress fibers. Gene expression assessed by quantitative real-time polymerase chain reaction of 9 genes encoding cell attachment proteins (Cd44, Ctnna1, Ctnnb1, Itga3, Itga5, Itgav, Itgb1, Ncam1, Sgce), 16 genes encoding extracellular matrix proteins (Col1a1, Col2a1, Col3a1, Col5a1, Col6a1, Ecm1, Emilin1, Fn1, Hapln1, Lamb3, Postn, Sparc, Spp1, Thbs1, Thbs2, Tnc), and 9 genes encoding modulators of remodeling (Adamts1, Adamts2, Ctgf, Mmp14, Mmp2, Tgfbi, Timp1, Timp2, Timp3) indicated that graphene foam provided a microenvironment conducive to expression of genes that are important in early chondrogenesis. Functionalization of graphene foam with fibronectin modified the cellular response to graphene foam, demonstrated by decreases in relative gene expression levels. These findings illustrate the combinatorial factors of microscale materials properties and nanoscale molecular features to consider in the design of three-dimensional graphene scaffolds for tissue engineering applications.
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Affiliation(s)
- Stephanie
M. Frahs
- Center
of Biomedical Research Excellence in Matrix Biology, Biomolecular
Research Center, Boise State University, Boise, Idaho 83725, United States
| | - Jonathon C. Reeck
- Center
of Biomedical Research Excellence in Matrix Biology, Biomolecular
Research Center, Boise State University, Boise, Idaho 83725, United States
| | - Katie M. Yocham
- Department
of Mechanical and Biomedical Engineering, Boise State University, Boise, Idaho 83725, United States
- Micron
School of Materials Science and Engineering, Boise State University, Boise, Idaho 83725, United States
| | - Anders Frederiksen
- University
of Southern Denmark, Department of Physics,
Chemistry and Pharmacy, Campusvej 55, 5230 Odense M, Denmark
| | - Kiyo Fujimoto
- Micron
School of Materials Science and Engineering, Boise State University, Boise, Idaho 83725, United States
| | - Crystal M. Scott
- Center
of Biomedical Research Excellence in Matrix Biology, Biomolecular
Research Center, Boise State University, Boise, Idaho 83725, United States
| | - Richard S. Beard
- Center
of Biomedical Research Excellence in Matrix Biology, Biomolecular
Research Center, Boise State University, Boise, Idaho 83725, United States
| | - Raquel J. Brown
- Center
of Biomedical Research Excellence in Matrix Biology, Biomolecular
Research Center, Boise State University, Boise, Idaho 83725, United States
| | - Trevor J. Lujan
- Department
of Mechanical and Biomedical Engineering, Boise State University, Boise, Idaho 83725, United States
| | - Ilia A. Solov’yov
- Department
of Physics, Carl von Ossietzky Universität
Oldenburg, Carl-von-Ossietzky-Straße
9-11, 26129 Oldenburg, Germany
| | - David Estrada
- Micron
School of Materials Science and Engineering, Boise State University, Boise, Idaho 83725, United States
| | - Julia Thom Oxford
- Center
of Biomedical Research Excellence in Matrix Biology, Biomolecular
Research Center, Boise State University, Boise, Idaho 83725, United States
- Department
of Biological Sciences, Boise State University, Boise, Idaho 83725, United States
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8
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Frederiksen A, Abrahamsen B, Johansen PB, Sørensen HA. Danish, national cross-sectional observational study on the prevalence of prior major osteoporotic fractures in adults presenting with hip fracture-limitations and scope for fracture liaison services in prevention of hip fracture. Osteoporos Int 2018; 29:109-114. [PMID: 28965215 DOI: 10.1007/s00198-017-4247-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 09/25/2017] [Indexed: 11/26/2022]
Abstract
UNLABELLED Fracture liaison services prevent hip fractures by identifying other osteoporotic fractures that generally debut at a younger age. However, this study showed that a minority of hip fracture patients are already known to the health services through having had prior osteoporotic fractures. Identification of vertebral fractures in particular is lacking. INTRODUCTION The purpose of this study was to examine the prevalence of prior major osteoporotic fractures (MOF) in the prior 10 years preceding hip fracture in order to provide information about the potential for prevention of hip fractures by fracture liaison services (FLS). METHODS We included all patients aged 50+ with surgically treated hip fracture in one calendar year (N = 8158) in the Danish Hospital Discharge Register. Prior fractures were identified using the same data source. A prior hip fracture was only included as a prior fracture if occurring more than 6 months before the present fracture. RESULTS A total of 28% of hip fracture patients (32% of women and 19% of men) had at least one recognized MOF in the preceding 10 years. Forearm and humerus fractures constituted > 70% of prior MOF. In both genders, vertebral fractures only represented a small percentage (2.6%) of previously recognized MOF. Men were less likely than women to have experienced a prior MOF, chiefly due to fewer forearm and humerus fractures. CONCLUSION The majority of hip fractures-and in particular hip fractures in men-occur without a previously treated MOF that could have resulted in early detection and treatment of osteoporosis. With current treatment modalities, a maximum of one in six hip fractures in Denmark can be prevented through FLS initiatives. Identification of patients with vertebral fractures for assessment and treatment is therefore critical for successful prevention of hip fractures using this strategy.
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Affiliation(s)
- A Frederiksen
- Department of Medicine, Holbæk Hospital, 4300, Holbæk, Denmark
| | - B Abrahamsen
- Department of Medicine, Holbæk Hospital, 4300, Holbæk, Denmark.
- Department of Clinical Research, Odense Patient Data Explorative Network, University of Southern Denmark, 5000, Odense, Denmark.
| | - P B Johansen
- Department of Medicine, Holbæk Hospital, 4300, Holbæk, Denmark
| | - H A Sørensen
- Department of Medicine, Holbæk Hospital, 4300, Holbæk, Denmark
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Abstract
In this article I study how companies can use their personnel data and information from job satisfaction surveys to predict employee quits. An important issue discussed at length in the article is how employers can ensure the anonymity of employees in surveys used for management and human resources (HR) analytics. I argue that a simple mechanism whereby the company delegates the implementation of job satisfaction surveys to an external consulting company can be optimal. In the subsequent empirical analysis, I use a unique combination of firm-level data (personnel records) and information from job satisfaction surveys to assess the benefits for companies using data in their decision-making. Moreover, I aim to show how companies can move from a descriptive to a predictive approach.
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Frederiksen A. [Nursing supervision at a psychiatric outpatient department]. Sairaanhoitaja 1975; 50:18-9. [PMID: 1043202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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