| 1. |
- Wickham, Abeni, et al.
(författare)
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Near-Infrared Emitting and Pro-Angiogenic Electrospun Conjugated Polymer Scaffold for Optical Biomaterial Tracking
- 2015
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Ingår i: Advanced Functional Materials. - : Wiley: 12 months. - 1616-301X .- 1616-3028. ; 25:27, s. 4274-4281
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Tidskriftsartikel (refereegranskat)abstract
- Noninvasive tracking of biomaterials is vital for determining the fate and degradation of an implant in vivo, and to show its role in tissue regeneration. Current biomaterials have no inherent capacity to enable tracing but require labeling with, for example, fluorescent dyes, or nanoparticles. Here a novel biocompatible fully conjugated electrospun scaffold is described, based on a semiconducting luminescent polymer that can be visualized in situ after implantation using fluorescence imaging. The polymer, poly [2,3-bis-(3-octyloxyphenyl)quinoxaline-5,8-diyl-alt -thiophene-2,5-diyl] (TQ1), is electrospun to form a fibrous mat. The fibers display fluorescence emission in the near-infrared region with lifetimes in the sub-nanosecond range, optimal for in situ imaging. The material shows no cytotoxic behaviors for embryonic chicken cardiomyocytes and mouse myoblasts, and cells migrate onto the TQ1 fibers even in the presence of a collagen substrate. Subcutaneous implantations of the material in rats show incorporation of the TQ1 fibers within the tissue, with limited inflammation and a preponderance of small capillaries around the fibers. The fluorescent properties of the TQ1 fibers are fully retained for up to 90 d following implantation and they can be clearly visualized in tissue using fluorescence and lifetime imaging, thus making it both a pro-angiogenic and traceable biomaterial.
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| 2. |
- Altenhoff, Adrian M., et al.
(författare)
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Standardized benchmarking in the quest for orthologs
- 2016
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Ingår i: Nature Methods. - 1548-7091 .- 1548-7105. ; 13:5, s. 425-
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Tidskriftsartikel (refereegranskat)abstract
- Achieving high accuracy in orthology inference is essential for many comparative, evolutionary and functional genomic analyses, yet the true evolutionary history of genes is generally unknown and orthologs are used for very different applications across phyla, requiring different precision-recall trade-offs. As a result, it is difficult to assess the performance of orthology inference methods. Here, we present a community effort to establish standards and an automated web-based service to facilitate orthology benchmarking. Using this service, we characterize 15 well-established inference methods and resources on a battery of 20 different benchmarks. Standardized benchmarking provides a way for users to identify the most effective methods for the problem at hand, sets a minimum requirement for new tools and resources, and guides the development of more accurate orthology inference methods.
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| 3. |
- Arja, Katriann, et al.
(författare)
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Enhanced Fluorescent Assignment of Protein Aggregates by an Oligothiophene-Porphyrin-Based Amyloid Ligand
- 2013
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Ingår i: Macromolecular rapid communications. - : Wiley-VCH Verlag. - 1022-1336 .- 1521-3927. ; 34:9, s. 723-730
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Tidskriftsartikel (refereegranskat)abstract
- Fluorescent probes identifying protein aggregates are of great interest, as deposition of aggregated proteins is associated with many devastating diseases. Here, we report that a fluorescent amyloid ligand composed of two distinct molecular moieties, an amyloidophilic pentameric oligothiophene and a porphyrin, can be utilized for spectral and lifetime imaging assessment of recombinant A 1-42 amyloid fibrils and A deposits in brain tissue sections from a transgenic mouse model with Alzheimers disease pathology. The enhanced spectral range and distinct lifetime diversity of this novel oligothiopheneporphyrin-based ligand allow a more precise assessment of heterogeneous amyloid morphology compared with the corresponding oligothiophene dye.
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| 4. |
- Babu Moparthi, Satish, et al.
(författare)
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Transient conformational remodeling of folding proteins by GroES - Individually and in concert with GroEL
- 2014
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Ingår i: Journal of chemical biology. - : Springer Berlin/Heidelberg. - 1864-6158 .- 1864-6166. ; 7:1, s. 1-15
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Forskningsöversikt (refereegranskat)abstract
- The commonly accepted dogma of the bacterial GroE chaperonin system entails protein folding mediated by cycles of several ATP-dependent sequential steps where GroEL interacts with the folding client protein. In contrast, we herein report GroES-mediated dynamic remodeling (expansion and compression) of two different protein substrates during folding: the endogenous substrate MreB and carbonic anhydrase (HCAII), a well-characterized protein folding model. GroES was also found to influence GroEL binding induced unfolding and compression of the client protein underlining the synergistic activity of both chaperonins, even in the absence of ATP. This previously unidentified activity by GroES should have important implications for understanding the chaperonin mechanism and cellular stress response. Our findings necessitate a revision of the GroEL/ES mechanism.
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| 5. |
- De Jong, Anna, et al.
(författare)
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Gastronomy Tourism : An Interdisciplinary Literature Review of Research Areas, Disciplines, and Dynamics
- 2018
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Ingår i: Journal of Gastronomy and Tourism. - 2169-2971 .- 2169-298X. ; 3:2, s. 131-146
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Tidskriftsartikel (refereegranskat)abstract
- Residing with the exponential growth of gastronomy tourism research, a number of review articles have examined the relationship of gastronomy and tourism from distinct thematic and disciplinary perspectives. What remains absent is a comprehensive overview that encapsulates the interdisciplinary dimensions of this area of research. In response, this study comprehensively investigates gastronomy tourism literature utilizing a network and content analysis, with an aim to map the main subject areas concerned with gastronomy tourism and relations between varying subject areas. In doing so, themes determining gastronomy tourism and focus for future exploration are identified. The review findings suggest that the trajectory of gastronomy tourism research is characterized by the dominance of "tourism, leisure, and hospitality management" and "geography, planning, and development." Three recommendations are proposed to assist development of gastronomy tourism research: increased dialogue across subject areas, development of critical and theoretical approaches, and greater engagement with sustainability debates.
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| 6. |
- Liberles, David A., et al.
(författare)
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The interface of protein structure, protein biophysics, and molecular evolution
- 2012
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Ingår i: Protein Science. - : Wiley. - 0961-8368 .- 1469-896X. ; 21:6, s. 769-785
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Forskningsöversikt (refereegranskat)abstract
- The interface of protein structural biology, protein biophysics, molecular evolution, and molecular population genetics forms the foundations for a mechanistic understanding of many aspects of protein biochemistry. Current efforts in interdisciplinary protein modeling are in their infancy and the state-of-the art of such models is described. Beyond the relationship between amino acid substitution and static protein structure, protein function, and corresponding organismal fitness, other considerations are also discussed. More complex mutational processes such as insertion and deletion and domain rearrangements and even circular permutations should be evaluated. The role of intrinsically disordered proteins is still controversial, but may be increasingly important to consider. Protein geometry and protein dynamics as a deviation from static considerations of protein structure are also important. Protein expression level is known to be a major determinant of evolutionary rate and several considerations including selection at the mRNA level and the role of interaction specificity are discussed. Lastly, the relationship between modeling and needed high-throughput experimental data as well as experimental examination of protein evolution using ancestral sequence resurrection and in vitro biochemistry are presented, towards an aim of ultimately generating better models for biological inference and prediction.
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| 7. |
- Magnusson, Karin, et al.
(författare)
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Multimodal fluorescene microscopy of prion strain specific PrP deposits stained by thiophene-bassed amyloid ligands
- 2014
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Ingår i: Prion. - : Taylor & Francis. - 1933-6896 .- 1933-690X. ; 8:4, s. 319-329
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Tidskriftsartikel (refereegranskat)abstract
- The disease-associated prion protein (PrP) forms aggregates which vary in structural conformation yet share identical primary sequence. These variations in PrP conformation are believed to manifest in prion strains exhibiting distinctly different periods of disease incubation as well as regionally specific aggregate deposition within the brain. The anionic luminescent conjugated polythiophene (LCP), polythiophene acetic acid (PTAA) has previously been used to distinguish PrP deposits associated with distinct mouse adapted strains via distinct fluorescence emission profiles from the dye. Here we employed PTAA and 3 structurally related chemically defined luminescent conjugated oligothiophenes (LCOs) to stain brain tissue sections from mice inoculated with 2 distinct prion strains. Our results showed that in addition to emission spectra, excitation, and fluorescence lifetime imaging microscopy (FLIM) can fruitfully be assessed for optical distinction of PrP deposits associated with distinct prion strains. Our findings support the theory that alterations in LCP/LCO fluorescence are due to distinct conformational restriction of the thiophene backbone upon interaction with PrP aggregates associated with distinct prion strains. We foresee that LCP and LCO staining in combination with multimodal fluorescence microscopy might aid in detecting structural differences among discrete protein aggregates and in linking protein conformational features with disease phenotypes for a variety of neurodegenerative proteinopathies.
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| 8. |
- Mishra, Rajesh, et al.
(författare)
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Spectroscopic characterization of diverse amyloid fibrils in vitro by the fluorescent dye Nile red
- 2011
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Ingår i: MOLECULAR BIOSYSTEMS. - : Royal Society of Chemistry. - 1742-206X .- 1742-2051. ; 7:4, s. 1232-1240
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Tidskriftsartikel (refereegranskat)abstract
- The fluorescence of Nile red (9-diethylamino-5H-benzophenoxazine-5-one) is quenched in aqueous solutions but shows augmented fluorescence in hydrophobic environments. Nile red fluorescence was blue shifted and strongly augmented in the presence of various amyloid fibrils assayed under acidic as well as neutral pH conditions. Fibrils grown from lysozyme and insulin (at pH 1.6 and 65 degrees C), transthyretin (TTR) fibrils grown from the acid unfolded monomer (pH 2.0, 21 degrees C) or from the dissociated tetramer starting from native protein under less acidic conditions (pH 4.4, 37 degrees C) were detected. Nile red was also successfully employed in detecting A beta 1-42 and human prion protein (PrP90-231) amyloid fibrils grown at neutral pH. Nile red was amyloid fibril specific and did not fluoresce appreciably in the presence of the monomeric precursor proteins. Stokes shifts of the wavelength maximum of Nile red bound to various fibrils were different (ranging from 615 nm to 638 nm) indicating sensitivity to the tertiary structure in its respective binding sites of different amyloid proteins. A polarity assay using ethanol-water mixtures and pure octanol ranging from dielectric constants between 10 and 70 showed a linear correlation of Nile red Stokes shift and allowed assignment of amyloid fibril binding site polarity. Fluorescence resonance energy transfer between Thioflavin T (ThT) and Nile red was proven to be efficient and co-staining was employed to discriminate between conformational isoforms of A beta 1-42 amyloid fibrils grown under agitated and quiescent conditions. This paper demonstrates the complementary use of this fluorometric method for conformational typing of amyloid structures.
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| 9. |
- Nordeman, Patrik, et al.
(författare)
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C-11 and F-18 Radiolabeling of Tetra- and Pentathiophenes as PET-Ligands for Amyloid Protein Aggregates
- 2016
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Ingår i: ACS Medicinal Chemistry Letters. - : American Chemical Society (ACS). - 1948-5875. ; 7:4, s. 368-373
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Tidskriftsartikel (refereegranskat)abstract
- Three oligothiophenes were evaluated as PET ligands for the study of local and systemic amyloidosis ex vivo using tissue from patients with amyloid deposits and in vivo using healthy animals and PET-CT. The ex vivo binding studies revealed that all three labeled compounds bound specifically to human amyloid deposits. Specific binding was found in the heart, kidney, liver, and spleen. To verify the specificity of the oligothiophenes toward amyloid deposits, tissue sections with amyloid pathology were stained using the fluorescence exhibited by the compounds and evaluated with multiphoton microscopy. Furthermore, a in vivo monkey PET-CT study showed very low uptake in the brain, pancreas, and heart of the healthy animal indicating low nonspecific binding to healthy tissue. The biological evaluations indicated that this is a promising group of compounds for the visualization of systemic and localized amyloidosis.
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| 10. |
- Sjölander, Daniel, et al.
(författare)
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Establishing the fluorescent amyloid ligand h-FTAA for studying human tissues with systemic and localized amyloid
- 2016
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Ingår i: Amyloid. - : Informa UK Limited. - 1350-6129 .- 1744-2818. ; 23:2, s. 98-108
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Tidskriftsartikel (refereegranskat)abstract
- Rapid and accurate detection of amyloid deposits in routine surgical pathology settings are of great importance. The use of fluorescence microscopy in combination with appropriate amyloid specific dyes is very promising in this regard. Here we report that a luminescent conjugated oligothiophene, h-FTAA, rapidly and with high sensitivity and selectivity detects amyloid deposits in verified clinical samples from systemic amyloidosis patients with AA, AL and ATTR types; as well as in tissues laden with localized amyloidosis of AANF, AIAPP and ASem1 type. The probe h-FTAA emitted yellow red fluorescence on binding to amyloid deposits, whereas no apparent staining was observed in surrounding tissue. The only functional structure stained with h-FTAA showing the amyloidotypic fluorescence spectrum was Paneth cell granules in intestine. Screening of 114 amyloid containing tissues derived from 107 verified (Congo red birefringence and/or immunohistochemistry) amyloidosis patients revealed complete correlation between h-FTAA and Congo red fluorescence (107/107, 100% sensitivity). The majority of Congo red negative control cases (27 of 32, 85% specificity) were negative with h-FTAA. Small Congo red negative aggregates in kidney, liver, pancreas and duodenum were found by h-FTAA fluorescence in five control patients aged 72-83 years suffering from diverse diseases. The clinical significance of these false-positive lesions is currently not known. Because h-FTAA fluorescence is one magnitude brighter than Congo red and as the staining is performed four magnitudes lower than the concentration of dye, we believe that these inclusions are beyond detection by Congo red. We conclude that h-FTAA is a fluorescent hypersensitive, rapid and powerful tool for identifying amyloid deposits in tissue sections. Use of h-FTAA can be exploited as a rapid complementary technique for accurate detection of amyloid in routine surgical pathology settings. Our results also implicate the potential of the technique for detection of prodromal amyloidosis as well as for discovery of new amyloid-like protein aggregates in humans.
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| 11. |
- Sjölander, Daniel, et al.
(författare)
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Evaluation of the fluorescent amyloid ligand h-FTAA in human tissues with systemic and localized amyloid
- 2014
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Rapid and accurate detection of amyloid deposits in routine surgical pathology settings are of great importance. The use of fluorescence microscopy in combination with appropriate amyloid specific dyes is very promising in this regard. Most systemic amyloidosis are progressive and lethal. Disease specific therapy depends on the identification of the offending proteins. Here we report that a luminescent conjugated oligothiophene, h-FTAA, rapidly and with high sensitivity and selectivity detects amyloid deposits in verified clinical samples from systemic amyloidosis patients with AA, AL, and ATTR types; as well as in tissues laden with localized amyloidosis of AANF, AIAPP and ASem1 type. The probe h-FTAA emitted yellow red fluorescence on binding to amyloid deposits, whereas no apparent staining was observed in surrounding tissue. Screening of 114 amyloid containing tissues derived from §07 verified (Congo red birefringence and immunohistochemistry) amyloidosis patients revealed complete correlation between h-FTAA and Congo red fluorescence. We conclude that h-FTAA is a fluorescent hypersensitive, rapid and powerful tool for identifying amyloid deposits in tissue sections. H-FTAA staining can be utilized as a rapid complementary technique for accurate detection of amyloid in routine surgical pathology settings. It was also revealed that within 5 of 15 age matched Congo red negative control samples h-FTAA detects microdeposits of amyloid-like protein aggregates in liver and kidney. The results emphasize the potential of the dye for detection of prodromal amyloidosis as well as for discovery of novel amyloid-like protein aggregates in humans.
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| 12. |
- Sjölander, Daniel, et al.
(författare)
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Luminescent conjugated oligothiophenes: A novel dye for amyloid diagnostics
- 2013
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Ingår i: XIIIth International Symposium on Amyloidosis. - : GUARD (Groningen Unit for Amyloidosis Research & Development). - 9789082159301 - 9789082159318 ; , s. 179-182
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Konferensbidrag (refereegranskat)abstract
- The alkaline Congo red staining method has, for almost half a century, been the gold standard of amyloid diagnosis. Unfortunately, the method is both laborious and requires great skill to achieve proper diagnosis. In this study we are presenting an alternative method that is compatible with immunofluorescence typing. We used a novel dye, h-FTAA, designed and synthesized by us. The dye belongs to the novel class of conformation sensitive dyes known as Luminescent conjugated oligothiophenes (LCOs). We examined 37 different cases of systemic amyloidoses from various tissues. It was found that h-FTAA binds to amyloid with higher sensitivity and greater selectivity than Congo red, as was determined by both fluorescence- and light polarization microscopy. Due to the methods ease of use and performance compared to Congo red, it is concluded that h-FTAA is a better first choice for screening of systemic amyloidoses.
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| 13. |
- Sjölander, Daniel
(författare)
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Luminescent molecular recognition of pathognomonic and aging associated protein aggregates
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Various protein inclusions have been recognized to be associated with aging and pathogenic conditions, such as in Alzheimer’s disease, Parkinson’s disease, Type 2 diabetes, and the prionoses Creutzfeldt-Jakob disease, Chronic wasting disease (CWD), and Mad cow disease. The causative transition of protein aggregation is the alteration in the conformation of the protein that renders the protein susceptible towards self-assembly. Variations in the physico-chemical ultrastructure of the protein deposit, i.e. the conformation and the chemical nature of the fibril constituent protein monomers, translate into specific structure-property phenotype, hence clinicopathology. Upon transmission and/or propagation this phenomenon gives rise to specific protein aggregate strains. Today most potential treatments of the protein conformational diseases have been a huge failure, effectively due to late diagnosis and subsequent therapeutic intervention. An imperative for efficient treatment is early detection and accurate identification for proper clinical diagnosis.The purpose of the studies in this thesis was to develop highly sensitive methods for detection and discrimination of age- and disease associated protein deposits both for in vitro and ex vivo utilization.Herein we have shown that, for in vitro usage, Nile red will bind to amyloid-like protein aggregates derived from a plethora of precursor proteins. It was also found that the fluorescence was insensitive to acidic assay conditions in contrast to the standard in vitro dye Thioflavin T (ThT). Further, Nile red was shown to discriminate between conformational isoforms thus enabling conformational typing of amyloid structures.For the development of ex vivo detection methods we employed luminescent conjugated oligothiophenes (LCOs) and utilized the structure-conformation induced optical properties of this class of protein aggregate ligands. The heptameric oligothiophene h-FTAA was successfully used to detect, with high sensitivity, protein deposits from various systemic amyloidoses (ATTR, AA, AL-λ/κ, and the local amyloidosis AIAPP) derived from biopsy specimens. Also aging-associated protein deposits were detected which was found promising for early detection of potentially pathogenic protein inclusions. Further, LCO staining of tissue sections was found compatible with immunolabeling enabling subtyping of involved proteins. Early detection of amyloidosis also requires relatively non-invasive methods, why h-FTAA staining was directed towards fine-needle-aspirated (FNA) abdominal fat tissue smears. Staining of protein deposits and detection with high sensitivity was also found in the fat tissue smears.In addition to the relatively rare prionoses it has lately been shown that Alzheimer’s, Parkinson’s diseases share similar properties as the prion pathologies. Hence the urgent need for ligands that will recognize specific disease specific strain aggregates. Using an established murine model for prion strain propagation we were able to discriminate two different prion strains, murine adapted Sheep Scrapie (mSS) and murine adapted Chronic wasting disease (mCWD) from each other by using multimodal fluorescence microscopy entailing emission/excitation spectral imaging and fluorescent lifetime imaging (FLIM).In conclusion we have shown that the LCOs will recognize protein aggregates with high sensitivity and selectivity. In addition we have shown that the LCOs detect protein aggregates that Congo red failed to recognize thus allowing potentially early diagnosis. Last, we show that the LCOs will recognize and discriminate between different protein aggregate strains which potentially will allow disease specific therapeutic targeting.
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| 14. |
- Sjölander, Daniel, et al.
(författare)
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Sensitive and rapid assessment of amyloid by oligothiophene fluorescence in subcutaneous fat tissue
- 2015
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Ingår i: Amyloid. - : Informa Healthcare. - 1350-6129 .- 1744-2818. ; 22:1, s. 19-25
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Tidskriftsartikel (refereegranskat)abstract
- Systemic amyloidosis (SA) is often diagnosed late. Combining clinical and biochemical biomarkers is necessary for raising suspicion of disease. Fine needle aspiration (FNA) of subcutaneous fat enables SA detection by Congo red staining. The luminescent conjugated probe heptameric formic thiophene acetic acid (h-FTAA) is a sensitive alternative to Congo red-staining of tissue samples. Our objective was to compare h-FTAA fluorescence with the Congo red stain for amyloid detection in FNA-obtained fat tissue. Herein, we studied samples from 57 patients with established SA (19 with AA, 20 with AL, and 18 with ATTR) and 17 age-matched controls (34–75 years). Positivity for h-FTAA was graded according to a Congo red-based grading scale ranging from 0 to 4+. Amyloid grading by both methods correlated strongly (r = 0.87). Here h-FTAA was positive in 53 of 54 Congo red-positive cases (sensitivity 98%) and h-FTAA was negative in 7 of 17 Congo red-negative controls (specificity 41%), but was also positive for 3 Congo red-negative SA cases. We conclude that h-FTAA fluorescence is more sensitive than Congo red staining in this small exploratory study of fat tissue samples, implicating potential sensitivity for prodromal amyloidosis, but is less specific for clinical amyloidosis defined by Congo red positivity. Given its simplicity h-FTAA staining may therefore be the most appropriate method for rapid screening of fat tissue samples but should presently treat grade 1+ as only suggestive, whereas 2+ or higher as positive for amyloidosis. Parallel assessment of h-FTAA and Congo red staining appears highly promising for clinical applications.
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| 15. |
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| 16. |
- Sjölander Lindqvist, Annelie, 1970, et al.
(författare)
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Craft beer – building social terroir through connecting people, place and business
- 2020
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Ingår i: Journal of Place Management and Development. - : Emerald Group Publishing Limited. - 1753-8335 .- 1753-8343. ; 13:2, s. 149-162
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Tidskriftsartikel (refereegranskat)abstract
- © 2019, Emerald Publishing Limited. Purpose: This paper aims to propose the concept of social terroir to help navigate phenomenological and epistemological conditions of small-scale food entrepreneurship. Design/methodology/approach: This study used a qualitative research approach and was implemented in the peripheral region of Jämtland in northern Sweden. The study interrogated the ambitions of craft brewers when starting up, their long-term goals and visions, including questions about the reason for starting up a brewery, how the different brewers cooperate and how and why the products are designed and labelled the way they are. Findings: This study shows that the production of craft beer is an inherently social practice that is part of a particular sociocultural milieu. This milieu informs production in distinct and interrelated ways: through connecting to place and locality in the different aspects of production and marketing, through cooperation to develop production and overcome barriers, and through embedding their work in sustainability discourses. Originality/value: The study addresses how, in the context of craft beer, terroir or taste of place, is a matter of social ties to place and community–social terroir. What is novel is the way in which social terroir becomes a critical ingredient in the production of craft beer. This illustrates how small-scale food production and gastronomic efforts can link people, places and businesses.
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