| 11. |
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| 12. |
- Poveda-Reyes, Sara, et al.
(författare)
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Injectable composites of loose microfibers and gelatin with improved interfacial interaction for soft tissue engineering
- 2015
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Ingår i: Polymer. - : Elsevier BV. - 0032-3861 .- 1873-2291. ; 74, s. 224-234
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Tidskriftsartikel (refereegranskat)abstract
- Poly(L-lactic acid) (PLLA) microfibers were surface functionalized by graft photopolymerization of 2-hydroxyethyl methacrylate (HEMA) onto the fiber surface. Grafted fibers were easily dispersed in enzymatically gelling tyramine-substituted gelatin, forming a homogeneous dispersion without hindering subsequent gelatin crosslinking. The obtained injectable hydrogels showed improved mechanical properties compared to analogues based on non-modified fibers. The composite with 1% (w/v) of surface modified fibers had a three-fold higher shear storage modulus (535.2 +/- 90 Pa) than pure gelatin (184.9 +/- 32 Pa) while no significant increase was observed in the case of non-grafted fiber composites. Moreover, PHEMA grafting on PLLA fibers did not compromise cell viability and proliferation within the hydrogel. The new injectable hydrogels offer improved potential as substrates for the regeneration of soft tissues.
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| 13. |
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| 14. |
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| 15. |
- Edlund, Petra, et al.
(författare)
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The room temperature crystal structure of a bacterial phytochrome determined by serial femtosecond crystallography
- 2016
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Phytochromes are a family of photoreceptors that control light responses of plants, fungi and bacteria. A sequence of structural changes, which is not yet fully understood, leads to activation of an output domain. Time-resolved serial femtosecond crystallography (SFX) can potentially shine light on these conformational changes. Here we report the room temperature crystal structure of the chromophore-binding domains of the Deinococcus radiodurans phytochrome at 2.1 angstrom resolution. The structure was obtained by serial femtosecond X-ray crystallography from microcrystals at an X-ray free electron laser. We find overall good agreement compared to a crystal structure at 1.35 angstrom resolution derived from conventional crystallography at cryogenic temperatures, which we also report here. The thioether linkage between chromophore and protein is subject to positional ambiguity at the synchrotron, but is fully resolved with SFX. The study paves the way for time-resolved structural investigations of the phytochrome photocycle with time-resolved SFX.
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| 16. |
- Godoy, Patricio, et al.
(författare)
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Gene networks and transcription factor motifs defining the differentiation of stem cells into hepatocyte-like cells
- 2015
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Ingår i: Journal of Hepatology. - : Elsevier. - 0168-8278 .- 1600-0641. ; 63:4, s. 934-942
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND & AIMS: The differentiation of stem cells to hepatocyte-like cells (HLC) offers the perspective of unlimited supply of human hepatocytes. However, the degree of differentiation of HLC remains controversial. To obtain an unbiased characterization, we performed a transcriptomic study with HLC derived from human embryonic and induced stem cells (ESC, hiPSC) from three different laboratories.METHODS: Genome-wide gene expression profiles of ESC and HLC were compared to freshly isolated and up to 14days cultivated primary human hepatocytes. Gene networks representing successful and failed hepatocyte differentiation, and the transcription factors involved in their regulation were identified.RESULTS: Gene regulatory network analysis demonstrated that HLC represent a mixed cell type with features of liver, intestine, fibroblast and stem cells. The "unwanted" intestinal features were associated with KLF5 and CDX2 transcriptional networks. Cluster analysis identified highly correlated groups of genes associated with mature liver functions (n=1057) and downregulated proliferation associated genes (n=1562) that approach levels of primary hepatocytes. However, three further clusters containing 447, 101, and 505 genes failed to reach levels of hepatocytes. Key TF of two of these clusters include SOX11, FOXQ1, and YBX3. The third unsuccessful cluster, controlled by HNF1, CAR, FXR, and PXR, strongly overlaps with genes repressed in cultivated hepatocytes compared to freshly isolated hepatocytes, suggesting that current in vitro conditions lack stimuli required to maintain gene expression in hepatocytes, which consequently also explains a corresponding deficiency of HLC.CONCLUSIONS: The present gene regulatory network approach identifies key transcription factors which require modulation to improve HLC differentiation.
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| 17. |
- Liljeruhm, Josefine, et al.
(författare)
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Engineering a palette of eukaryotic chromoproteins for bacterial synthetic biology
- 2018
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Ingår i: Journal of Biological Engineering. - : BIOMED CENTRAL LTD. - 1754-1611. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Background: Coral reefs are colored by eukaryotic chromoproteins (CPs) that are homologous to green fluorescent protein. CPs differ from fluorescent proteins (FPs) by intensely absorbing visible light to give strong colors in ambient light. This endows CPs with certain advantages over FPs, such as instrument-free detection uncomplicated by ultra-violet light damage or background fluorescence, efficient Forster resonance energy transfer (FRET) quenching, and photoacoustic imaging. Thus, CPs have found utility as genetic markers and in teaching, and are attractive for potential cell biosensor applications in the field. Most near-term applications of CPs require expression in a different domain of life: bacteria. However, it is unclear which of the eukaryotic CP genes might be suitable and how best to assay them.Results: Here, taking advantage of codon optimization programs in 12 cases, we engineered 14 CP sequences (meffRed, eforRed, asPink, spisPink, scOrange, fwYellow, amilGFP, amajLime, cjBlue, mefiBlue, aeBlue, amilCP, tsPurple and gfasPurple) into a palette of Escherichia coil BioBrick plasmids. BioBricks comply with synthetic biology's most widely used, simplified, cloning standard. Differences in color intensities, maturation times and fitness costs of expression were compared under the same conditions, and visible readout of gene expression was quantitated. A surprisingly large variation in cellular fitness costs was found, resulting in loss of color in some overnight liquid cultures of certain high-copy-plasmid-borne CPs, and cautioning the use of multiple CPs as markers in competition assays. We solved these two problems by integrating pairs of these genes into the chromosome and by engineering versions of the same CP with very different colors.Conclusion: Availability of 14 engineered CP genes compared in E coil, together with chromosomal mutants suitable for competition assays, should simplify and expand CP study and applications. There was no single plasmid-borne CP that combined all of the most desirable features of intense color, fast maturation and low fitness cost, so this study should help direct future engineering efforts.
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| 18. |
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| 19. |
- O'Reilly, Ciarán J., et al.
(författare)
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Life cycle energy optimisation : A proposed methodology for integrating environmental considerations early in the vehicle engineering design process
- 2016
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Ingår i: Journal of Cleaner Production. - : Elsevier Ltd. - 0959-6526 .- 1879-1786. ; 135, s. 750-759
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Tidskriftsartikel (refereegranskat)abstract
- To enable the consideration of life cycle environmental impacts in the early stages of vehicle design, a methodology using the proxy of life cycle energy is proposed in this paper. The trade-offs in energy between vehicle production, operational performance and end-of-life are formulated as a mathematical problem, and simultaneously balanced with other transport-related functionalities, and may be optimised. The methodology is illustrated through an example design study, which is deliberately kept simple in order to emphasise the conceptual idea. The obtained optimisation results demonstrate that there is a unique driving-scenario-specific design solution, which meets functional requirements with a minimum life cycle energy cost. The results also suggest that a use-phase focussed design may result in a solution, which is sub-optimal from a life cycle point-of-view. © 2016 The Authors
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| 20. |
- Shcherbina, L, et al.
(författare)
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Endogenous beta-cell CART regulates insulin secretion and transcription of beta-cell genes
- 2017
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Ingår i: Molecular and Cellular Endocrinology. - : Elsevier BV. - 1872-8057 .- 0303-7207. ; 447, s. 52-60
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Tidskriftsartikel (refereegranskat)abstract
- Impaired beta-cell function is key to the development of type 2 diabetes. Cocaine- and amphetamine-regulated transcript (CART) is an islet peptide with insulinotropic and glucagonostatic properties. Here we studied the role of endogenous CART in beta-cell function. CART silencing in INS-1 (832/13) beta-cells reduced insulin secretion and production, ATP levels and beta-cell exocytosis. This was substantiated by reduced expression of several exocytosis genes, as well as reduced expression of genes important for insulin secretion and processing. In addition, CART silencing reduced the expression of a network of transcription factors essential for beta-cell function. Moreover, in RNAseq data from human islet donors, CARTPT expression levels correlated with insulin, exocytosis genes and key beta-cell transcription factors. Thus, endogenous beta-cell CART regulates insulin expression and secretion in INS-1 (832/13) cells, via actions on the exocytotic machinery and a network of beta-cell transcription factors. We conclude that CART is important for maintaining the beta-cell phenotype.
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