| 1. |
- Gyllenhammar, Andreas, et al.
(författare)
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Flodpärlmussla, Resultat från inventeringarna 1996-2005
- 2005
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- I denna rapport redovisas de insatser som gjorts för att kartlägga Jämtlands läns bestånd av flodpärlmussla (Margaritifera margaritifera). En kartläggning av historiska bestånd har gjorts, mestadels baserad på litteraturstudier. I rapporten redovisas resultaten från det inventeringsarbete som utförts av Länsstyrelsen i Jämtlands län åren 1996-2005. Resultaten presenteras i form av kartor, figurer och tabeller där beståndens geografiska lokalisering, storlek och reproduktionsstatus redovisas. Länet har idag 53 lokaler med bestånd av flodpärlmussla. I 30 stycken av dessa bestånd förekommer reproduktion men i över hälften (18st) är reproduktionen svag. 12 av bestånden har ett uppskattat individantal på över 10000 individer. Jämtland har i dagsläget Sveriges största bestånd av flodpärlmussla. I Storån, norr om Hammerdal, har antalet individer beräknats till 4,5 miljoner. En mer omfattande analys av läget för flodpärlmusslan i länet kommer att göras då inventeringsmaterialet datalagts i större omfattning och då ytterligare miljödata finns sammanställda. Slutsatserna pekar på vikten av att ytterligare miljödata tillgängliggörs för att möjliggöra en fördjupad analys av musselbeståndens och omgivningsparametrarnas status. Slutligen presenteras hur Länsstyrelsens arbete med flodpärlmussla kommer att fortskrida under 2006, med bl a utformning av ett miljöövervakningsprogram och planering av skyddsåtgärder.
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| 2. |
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| 3. |
- Karlsson, Roger, et al.
(författare)
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Iron-Catalyzed Polymerization of Alkoxysulfonate-Functionalized 3,4-Ethylenedioxythiophene Gives Water-Soluble Poly(3,4-ethylenedioxythiophene) of High Conductivity
- 2009
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Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 21:9, s. 1815-1821
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Tidskriftsartikel (refereegranskat)abstract
- Chemical polymerization of a 3,4-ethylenedioxythiophene derivative bearing a sulfonate group (EDOTS) is reported. The polymer, PEDOT-S, is fully water-soluble and has been produced by polymerizing EDOT-S in water, using Na2S2O8 and a catalytic amount of FeCl 3. Elemental analysis and XPS measurements indicate that PEDOT-S is a material with a substantial degree of self-doping, but also contains free sulfate ions as charge-balancing counterions of the oxidized polymer. Apart from selfdoping PEDOT-S, the side chains enable full water solubility of the material; DLS studies show an average cluster size of only 2 nm. Importantly, the solvation properties of the PEDOT-S are reflected in spin-coated films, which show a surface roughness of 1.2 nm and good conductivity (12 S/cm) in ambient conditions. The electro-optical properties of this material are shown with cyclic voltammetry and spectroelectrochemical experiment reveals an electrochromic contrast (̃48% at λmax ) 606 nm).
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| 4. |
- Li, Feng, et al.
(författare)
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Formation of nanotapes by co-assembly of triblock peptide copolymers and polythiophenes in aqueous solution
- 2009
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Ingår i: SOFT MATTER. - : Royal Society of Chemistry (RSC). - 1744-683X .- 1744-6848. ; 5:8, s. 1668-1673
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Tidskriftsartikel (refereegranskat)abstract
- Nanotapes are formed by the co-assembly of triblock peptide copolymers with an amino acid-substituted polythiophene derivative (PTT). The driving force for the assembly is ionic interaction (complex coacervation). These nanotapes were visualized by atomic force microscopy and confocal laser scanning microscopy. The interactions between the triblock peptide copolymers and the PTT are also expressed in the steady state and time resolved fluorescence spectra. The steady-state spectra indicate that upon interaction with the peptide copolymer, the backbone of the PTT adopts a rather twisted, and definitely less, aggregated conformation. The time-resolved fluorescence decay studies further confirm this interpretation. The structure of these nanotapes at the mesoscopic scale depends, among other physical chemical parameters, on the concentrations of its constituents.
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| 5. |
- Nilsson, K. Peter R., et al.
(författare)
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Imaging distinct conformational states of amyloid-beta fibrils in Alzheimer's disease using novel luminescent probes
- 2007
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Ingår i: ACS Chemical Biology. - : American Chemical Society (ACS). - 1554-8929 .- 1554-8937. ; 2:8, s. 553-560
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Tidskriftsartikel (refereegranskat)abstract
- Using luminescent conjugated polyelectrolyte probes (LCPs), we demonstrate the possibility to distinguish amyloid-β 1–42 peptide (Aβ1–42) fibril conformations, by analyzing in vitro generated amyloid fibrils of Aβ1–42 formed under quiescent and agitated conditions. LCPs were then shown to resolve such conformational heterogeneity of amyloid deposits in vivo. A diversity of amyloid deposits depending upon morphology and anatomic location was illustrated with LCPs in frozen ex vivo brain sections from a transgenic mouse model (tg-APP swe) of Alzheimer’s disease. Comparative LCP fluorescence showed that compact-core plaques of amyloid β precursor protein transgenic mice were composed of rigid dense amyloid. A more abundant form of amyloid plaque displayed morphology of a compact center with a protruding diffuse exterior. Surprisingly, the compact center of these plaques showed disordered conformations of the fibrils, and the exterior was composed of rigid amyloid protruding from the disordered center. This type of plaque appears to grow from more loosely assembled regions toward solidified amyloid tentacles. This work demonstrates how application of LCPs can prove helpful to monitor aggregate structure of in vivo formed amyloid deposits such as architecture, maturity, and origin.
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| 6. |
- Nilsson, Peter, et al.
(författare)
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Imaging distinct conformational states of amyloid-β fibrils in Alzheimer's disease using novel luminescent probes
- 2007
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Ingår i: ACS Chemical Biology. - : American Chemical Society (ACS). - 1554-8929 .- 1554-8937. ; 2:8, s. 553-560
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Tidskriftsartikel (refereegranskat)abstract
- Using luminescent conjugated polyelectrolyte probes (LCPs), we demonstrate the possibility to distinguish amyloid-β 1-42 peptide (Aβ1-42) fibril conformations, by analyzing in vitro generated amyloid fibrils of Aβ1-42 formed under quiescent and agitated conditions. LCPs were then shown to resolve such conformational heterogeneity of amyloid deposits in vivo. A diversity of amyloid deposits depending upon morphology and anatomic location was illustrated with LCPs in frozen ex vivo brain sections from a transgenic mouse model (tg-APPswe) of Alzheimer's disease. Comparative LCP fluorescence showed that compact-core plaques of amyloid β precursor protein transgenic mice were composed of rigid dense amyloid. A more abundant form of amyloid plaque displayed morphology of a compact center with a protruding diffuse exterior. Surprisingly, the compact center of these plaques showed disordered conformations of the fibrils, and the exterior was composed of rigid amyloid protruding from the disordered center. This type of plaque appears to grow from more loosely assembled regions toward solidified amyloid tentacles. This work demonstrates how application of LCPs can prove helpful to monitor aggregate structure of in vivo formed amyloid deposits such as architecture, maturity, and origin.
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| 7. |
- Åslund, Andreas, 1978-
(författare)
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Designing thiophene-based fluorescent probes for the study of neurodegenerative protein aggregation diseases : From test tube to in vivo experiments
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Protein aggregation is an event related to numerous neurodegenerative diseases, such as Alzhemier’s disease and prion diseases. However little is known as to how and why the aggregates form and furthermore, the toxic specie may not be the mature fibril but an on route or off route specie towards mature aggregates. During this project molecular probes were synthesized that may shed some light to these questions. The probes are thiophene based and the technique used for detection was mainly fluorescence. It was shown that the previously established thiophene based in vitro staining technique is valid ex vivo and in vivo. This would not have been possible without the synthesis of a variety of functionalized polymeric thiophene based probes; their in vitro and ex vivo staining properties were taken into consideration when the design of the small oligomeric probes were decided upon. These probes were shown to spectrally distinguish different types of amyloid, pass the bloodbrain barrier within minutes and specifically and selectively stain protein aggregates in the brains of mice.
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| 8. |
- Åslund, Andreas, et al.
(författare)
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Novel Pentameric Thiophene Derivatives for in Vitro and in Vivo Optical Imaging of a Plethora of Protein Aggregates in Cerebral Amyloidoses
- 2009
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Ingår i: ACS CHEMICAL BIOLOGY. - : American Chemical Society (ACS). - 1554-8929 .- 1554-8937. ; 4:8, s. 673-684
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Tidskriftsartikel (refereegranskat)abstract
- Molecular probes for selective Identification of protein aggregates are important to advance our understanding of the molecular pathogenesis underlying cerebral amyloidoses. Here we report the chemical design of pentameric thiophene derivatives, denoted luminescent conjugated oligothiophenes (LCOs), which could be used for real-time visualization of cerebral protein aggregates in transgenic mouse models of neurodegenerative diseases by multiphoton microscopy. One of the LCOs, p-FTAA, could be utilized for ex vivo spectral assignment of distinct prion deposits from two, mouse-adapted prion strains. p-FTAA also revealed a transient soluble pre-fibrillar non-thioflavinophilic A beta-assemblies during in vitro fibrillation of A beta peptides. In brain tissue samples, A beta deposits and neurofibrillary tangles (NFTs) were readily identified by a strong fluorescence from p-FTAA and the LCO staining showed complete co-localliation with conventional antibodies (6E10 and AT8). In addition, a patchy islet-like staining of individual A beta plaque was unveiled by the anti-oligomer A11 antibody during co-staining with p-FTAA. The major hallmarks of Alzheimers disease, namely, A beta aggregates versus NFTs, could also be distinguished because of distinct emission spectra from p-FTAA. Overall, we demonstrate that LCOs can be utilized as powerful practical research tools for studying protein aggregation diseases and facilitate the study of amyloid origin, evolution and maturation, A beta-tau interactions, and pathogenesis both ex vivo and in vivo.
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| 9. |
- Åslund, Andreas, et al.
(författare)
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Studies of luminescent conjugated polythiophene derivatives-Enhanced spectral discrimination of protein conformational states
- 2007
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Ingår i: Bioconjugate chemistry. - : American Chemical Society (ACS). - 1043-1802 .- 1520-4812. ; 18:6, s. 1860-1868
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Tidskriftsartikel (refereegranskat)abstract
- Improved probes for amyloid fibril formation are advantageous for the early detection and better understanding of this disease-associated process. Here, we report a comparative study of eight luminescent conjugated polythiophene derivates (LCPs) and their discrimination of a protein (insulin) in the native or amyloid-like fibrillar state. For two of the LCPs, the synthesis is reported. Compared to their monomer-based analogues, trimer-based LCPs showed significantly better optical signal specificity for amyloid-like fibrils, seen from increased quantum yield and spectral shift. The trimer-based LCPs alone were highly quenched and showed little interaction with native insulin, as seen from analytical ultracentrifugation and insignificant spectral differences from the trimer-based LCP in buffered and native protein solution. Hence, the trimer-based LCPs showed enhanced discrimination between the amyloid-like fibrillar state and the corresponding native protein.
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