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- Andersson, Rebecca, et al.
(författare)
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Differential role of cytosolic Hsp70s in longevity assurance and protein quality control
- 2021
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Ingår i: PLoS Genetics. - : Public Library of Science (PLoS). - 1553-7404 .- 1553-7390. ; 17:1
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Tidskriftsartikel (refereegranskat)abstract
- 70 kDa heat shock proteins (Hsp70) are essential chaperones of the protein quality control network; vital for cellular fitness and longevity. The four cytosolic Hsp70's in yeast, Ssa1-4, are thought to be functionally redundant but the absence of Ssa1 and Ssa2 causes a severe reduction in cellular reproduction and accelerates replicative aging. In our efforts to identify which Hsp70 activities are most important for longevity assurance, we systematically investigated the capacity of Ssa4 to carry out the different activities performed by Ssa1/2 by overproducing Ssa4 in cells lacking these Hsp70 chaperones. We found that Ssa4, when overproduced in cells lacking Ssa1/2, rescued growth, mitigated aggregate formation, restored spatial deposition of aggregates into protein inclusions, and promoted protein degradation. In contrast, Ssa4 overproduction in the Hsp70 deficient cells failed to restore the recruitment of the disaggregase Hsp104 to misfolded/aggregated proteins, to fully restore clearance of protein aggregates, and to bring back the formation of the nucleolus-associated aggregation compartment. Exchanging the nucleotide-binding domain of Ssa4 with that of Ssa1 suppressed this 'defect' of Ssa4. Interestingly, Ssa4 overproduction extended the short lifespan of ssa1 Delta ssa2 Delta mutant cells to a lifespan comparable to, or even longer than, wild type cells, demonstrating that Hsp104-dependent aggregate clearance is not a prerequisite for longevity assurance in yeast. Author summary All organisms have proteins that network together to stabilize and protect the cell throughout its lifetime. One of these types of proteins are the Hsp70s (heat shock protein 70). Hsp70 proteins take part in folding other proteins to their functional form, untangling proteins from aggregates, organize aggregates inside the cell and ensure that damaged proteins are destroyed. In this study, we investigated three closely related Hsp70 proteins in yeast; Ssa1, 2 and 4, in an effort to describe the functional difference of Ssa4 compared to Ssa1 and 2 and to answer the question: What types of cellular stress protection are necessary to reach a normal lifespan? We show that Ssa4 can perform many of the same tasks as Ssa1 and 2, but Ssa4 doesn't interact in the same manner as Ssa1 and 2 with other types of proteins. This leads to a delay in removing protein aggregates created after heat stress. Ssa4 also cannot ensure that misfolded proteins aggregate correctly inside the nucleus of the cell. However, this turns out not to be necessary for yeast cells to achieve a full lifespan, which shows us that as long as cells can prevent aggregates from forming in the first place, they can reach a full lifespan.
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| 3. |
- Carlsson, Daniel O., et al.
(författare)
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Electroactive nanofibrillated cellulose aerogel composites with tunable structural and electrochemical properties
- 2012
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 22:36, s. 19014-19024
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Tidskriftsartikel (refereegranskat)abstract
- This work presents conductive aerogel composites of nanofibrillated cellulose (NFC) and polypyrrole (PPy) with tunable structural and electrochemical properties. The conductive composites are prepared by chemically polymerizing pyrrole onto TEMPO-oxidized cellulose nanofibers dispersed in water and the various nanostructures are obtained employing different drying methods. Supercritical CO2 drying is shown to generate high porosity aerogel composites with the largest surface area (246 m(2) g(-1)) reported so far for a conducting polymer-paper based material, whereas composites produced by ambient drying attain high density structures with mechanical properties significantly surpassing earlier reported values for cellulose-conducting polymer composites when normalized with respect to the content of reinforcing cellulose (Young's modulus = 0.51 GPa, tensile strength = 10.93 MPa and strain to failure = 2.5%). Electrochemical measurements clearly show that differences in the porosity give rise to dramatic changes in the voltammetric and chronoamperometric behavior of the composites. This indicates that mass transport rate limitations also should be considered, in addition to the presence of a distribution of PPy redox potentials, as an explanation for the shapes of the voltammetric peaks. A specific charge capacity of similar to 220 C g(-1) is obtained for all composites in voltammetric experiments performed at a scan rate of 1 mV s(-1) and this capacity is retained also at scan rates up to 50 mV s(-1) for the high porosity composites. The composites should be applicable as electrodes in structural batteries and as membranes in ion exchange applications requiring exchange membranes of high mechanical integrity or high porosity.
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| 6. |
- Garemark, Jonas
(författare)
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Integrated Cellulosic Wood Aerogel Structures
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Highly porous aerogels based on renewable materials that possess structural functionality are appealing for sustainable energy regulation and harvesting. Achieving structural anisotropy provides advantageous directional diffusion and mechanical strength, however, introduces great engineering challenges, such as complex, costly, and time-consuming processing. Direct use of wood, where nanocellulose is favorably orientated, offers the opportunity of forming low-cost, scalable, and eco-friendly aerogels.This thesis explores a new type of nanostructured wood material design by filling the empty wood space with cellulosic aerogel structures based on its intrinsic biopolymers. The structure control is achieved through selective reassembly of the cell wall nanocomponents by cell wall partial dissolution and regeneration. The resultant structures, named integrated wood aerogels, show a unique combination of high specific surface area and strength due to partial retention of the wood hierarchical structure and formation of mesoporous nanofibrillated networks occupying the lumen. Different chemical systems are investigated, including DMAc/LiCl, ionic liquid (IL), and aqueous NaOH, and the processing-structure-property relationships are investigated. DMAc/LiCl is successfully used as proof of concept for integrated wood aerogel formation, but moisture sensitivity and toxicity of the system hinder further development. The IL [MTBD][MMP] is developed to solve the issues and to improve the structure control in cell wall dissolution and regeneration. An aqueous NaOH system advances the integrated cellulosic wood aerogel preparation further, considering low cost and greener chemistry. Wood composition, lignin in particular, is critical to the processing and final properties of the integrated wood aerogel. The influence of lignin content is investigated based on IL and NaOH systems. The influence of processing (such as chemical system, time and temperature) on the structure and properties (e.g. porosity, specific surface area, mechanical performance, thermal conductivity and charge density) of the aerogels are studied. Ascribing to the structure-property profile, the application of the integrated aerogel for efficient thermal insulation is demonstrated. Inspired by the water uptake in plants, high-performing pH-responsive wood power generators are formed based on water evaporation-induced electricity. The integrated aerogel structure greatly increases the solid/liquid interphase while allowing excellent mass diffusion.The methodologies presented in this thesis for selective nanoscale reassembly of the wood cell wall pave the way for advanced wood nanostructure control. The integrated wood aerogel structure reported here provides a universal material platform for advanced material design, such as a self-sustaining wood power generator. The facile and scalable processing contribute toward sustainable high-performing bioaerogels which can compete with fossil-based materials.
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| 7. |
- Gudehn, Ann
(författare)
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Miljöpåverkan från små lackeringsföretag
- 1997
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Under 1996 genomförde nio av Gävleborgs kommuner en gemensam inventerings-och tillsynskampanj. Kampanjen omfattade små företag som lackerar bilar, metall eller trä sammanlagt besöktes 75 företag.Syftet var att:Skaffa en uppfattning om den totala lösningsmedelsandningen hos relativt små användare för att kunna jämföra detta med övriga lösningsmedelsutsläpp i länet.Bedriva tillsyn hos lösningsmedelsanvändare i syfte att minska utsläpp av lösningsmedel till luft och vatten samt att förbättra hanteringen av avfall hos de aktuella företagen.
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| 8. |
- Hamedi, Mahiar, et al.
(författare)
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Nanocellulose Aerogels Functionalized by Rapid Layer-by-Layer Assembly for High Charge Storage and Beyond
- 2013
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Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 52:46, s. 12038-12042
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Tidskriftsartikel (refereegranskat)abstract
- Step by step: A robust and rapid method for the layer-by-layer assembly of polymers and nanoparticles on strong and elastic aerogels has been developed. Thin films of biomolecules, conducting polymers, and carbon nanotubes were assembled, which resulted in aerogels with a number of functions, including a high charge-storage capacity.
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| 10. |
- Jonsson, Gustav, et al.
(författare)
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Integrating yoga with psychological group-treatment for mixed depression and anxiety in primary healthcare: An explorative pilot study
- 2020
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Ingår i: Complementary Therapies in Clinical Practice. - : Elsevier. - 1744-3881 .- 1873-6947. ; 41
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose: Yoga has shown promise as a treatment for depression and anxiety. The present pilot study investigated the feasibility of an eight-week grouptreatment integrating emotion-focused psychoeducation, compassion-focused therapy, and Virya yoga for depression and anxiety in primary healthcare.Materials and methods: Patients seeking treatment for depression and anxiety in a primary healthcare centre completed either an integrative group-treatment (N = 14) or treatment as usual (TAU, N = 17). Outcome measures were analysed pre- and posttreatment. Correlations in the intervention group were investigated between treatment outcomes and amount of yoga practice between sessions.Results: Large within-group effect sizes on all outcome measures were found at posttreatment. Symptom reduction did not differ between groups (p = 0.155). Improvement in alexithymia correlated significantly (p < 0.05) with amount of yoga practice between sessions.Conclusion: Integrating yoga with a psychological group-treatment is a somewhat feasible approach to treatment for depression and anxiety in primary healthcare.
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