| 1. |
- Gustafsson, Lena, et al.
(författare)
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Rapid ecological response and intensified knowledge accumulation following a north European mega-fire
- 2019
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 34:4, s. 234-253
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Forskningsöversikt (refereegranskat)abstract
- Deepened knowledge on response of biota and ecological processes following fire is essential for a future with warmer climate and more disturbances. In 2014 the first mega-fire (13,100 ha) for at least a century in Scandinavia hit south-central Sweden, in a production forest landscape shaped by clearcutting forestry. Ecological dynamics is followed in >20 projects from universities, authorities and citizen science initiatives, rapidly accumulating substantial amounts of data. We outline projects and summarize their results during the first four years, demonstrating a rapid succession of fungi, lichens, vascular plants, birds, mammals, ticks, butterflies, beetles, and drastically altered carbon dynamics. We characterize forest operations including regeneration measures and point to patterns in pest and pathogen infestations. 8,000 ha is set aside for natural succession, with the rest harvested and managed for forest production, offering excellent opportunities for studies on salvage logging effects, already evident for birds. We demonstrate a strong regrowth of deciduous trees, and the protected part will in some decades likely develop into the largest deciduous-dominated area in boreal north Europe outside Russia. Continued studies of biodiversity and ecological processes are urgent for this unique area.
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| 2. |
- Wu, Siqin, et al.
(författare)
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TGF-beta enforces senescence in Myc-transformed hematopoietic tumor cells through induction of Mad1 and repression of Myc activity
- 2009
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Ingår i: Experimental Cell Research. - : Elsevier BV. - 0014-4827 .- 1090-2422. ; 315:18, s. 3099-3111
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Tidskriftsartikel (refereegranskat)abstract
- Inhibition of tumor growth factor (TGF)-beta-mediated cell cycle exit is considered an important tumorigenic function of Myc oncoproteins. Here we found that TGF-beta1 enforced G(1) cell cycle arrest and cellular senescence in human U-937 myeloid tumor cells ectopically expressing v-Myc, which contains a stabilizing mutation frequently found in lymphomas. This correlated with induced expression of the Myc antagonist Mad1, resulting in replacement of Myc for Mad1 at target promoters, reduced histone acetylation and strong repression of Myc-driven transcription. The latter was partially reversed by histone deacetylase (HDAC) inhibitors, consistent with involvement of Mad1. Importantly, knockdown of MAD1 expression prevented TGF-beta1-induced senescence, underscoring that Mad1 is a crucial component of this process. Enforced Mad1 expression sensitized U-937-myc cells to TGF-beta and restored phorbol ester-induced cell cycle exit, but could not alone induce G(1) arrest, suggesting that Mad1 is required but not sufficient for cellular senescence. Our results thus demonstrate that TGF-beta can override Myc activity despite a stabilizing cancer mutation and induce senescence in myeloid tumor cells, at least in part by induction of Mad1. TGF-beta-induced senescence, or signals mimicking this pathway, could therefore potentially be explored as a therapeutic principle for treating hematopoietic and other tumors with deregulated MYC expression.
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| 3. |
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| 4. |
- Guerra, Lina, et al.
(författare)
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Myc is required for activation of the ATM-dependent checkpoints in response to DNA damage
- 2010
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Ingår i: PLOS ONE. - : Public Library Science. - 1932-6203. ; 5:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The MYC protein controls cellular functions such as differentiation, proliferation, and apoptosis. In response to genotoxic agents, cells overexpressing MYC undergo apoptosis. However, the MYC-regulated effectors acting upstream of the mitochondrial apoptotic pathway are still unknown.PRINCIPAL FINDINGS: In this study, we demonstrate that expression of Myc is required to activate the Ataxia telangiectasia mutated (ATM)-dependent DNA damage checkpoint responses in rat cell lines exposed to ionizing radiation (IR) or the bacterial cytolethal distending toxin (CDT). Phosphorylation of the ATM kinase and its downstream effectors, such as histone H2AX, were impaired in the myc null cell line HO15.19, compared to the myc positive TGR-1 and HOmyc3 cells. Nuclear foci formation of the Nijmegen Breakage Syndrome (Nbs) 1 protein, essential for efficient ATM activation, was also reduced in absence of myc. Knock down of the endogenous levels of MYC by siRNA in the human cell line HCT116 resulted in decreased ATM and CHK2 phosphorylation in response to irradiation. Conversely, cell death induced by UV irradiation, known to activate the ATR-dependent checkpoint, was similar in all the cell lines, independently of the myc status.CONCLUSION: These data demonstrate that MYC contributes to the activation of the ATM-dependent checkpoint responses, leading to cell death in response to specific genotoxic stimuli.
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| 5. |
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| 6. |
- Södergren, Julia, et al.
(författare)
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Food waste to new food : Risk assessment and microbial community analysis of anaerobic digestate as a nutrient source in hydroponic production of vegetables
- 2022
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Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526 .- 1879-1786. ; 333
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Tidskriftsartikel (refereegranskat)abstract
- In this study, the microbiological food safety of using anaerobic digestate as a fertilizer in hydroponic production of vegetables was evaluated. The used anaerobic digestate was a liquid residue obtained from the digestion of food waste in the production of biogas. Replacing the customary inorganic fertilizer used in hydroponic production with this recycled fertilizer (biofertilizer) could allow for sustainable urban food production close to retailers and consumers. However, in striving for circular food production, it is vital that the food safety of utilizing recycled resources is ensured. Especially in the application of hydroponic farming, where the nutrient loop is shorter than on arable land, a microbiological food safety risk assessment is crucial when adopting new and recycled fertilizers. The biofertilizer based on anaerobic digestate was therefore studied with regard to its microbial community (16S rRNA gene amplicon sequencing) during production of vegetables in a hydroponic system. The biofertilizer was also challenge tested with food borne pathogens (Salmonella enterica, Listeria monocytogenes and Bacillus cereus). Furthermore, the microbial activity of the biofertilizer was studied using isothermal calorimetry. The results showed that the microbial community of the biofertilizer changed distinctly through a necessary initial nitrification process, and that the most abundant genus was Mycobacterium. Deliberate contaminations with 5 log10 CFU mL−1 of either S. enterica or L. monocytogenes in the nitrified biofertilizer were no longer detectable with selective plating after 48 h of incubation at 20 °C. Selective plating for B. cereus revealed that the biofertilizer contained low levels (∼10 CFU mL−1) of the bacterium, and an inoculation of 5 log10 CFU mL−1 B. cereus decreased to these levels within 24 h of incubation at 20 °C. Analysis of the microbial activity of the biofertilizer indicated that the biofertilizer does not seem to support microbial activity without the addition of an external nutrient source that contains an accessible carbon source and trace elements. The type of biofertilizer investigated in this study is thus regarded as microbiologically safe for use in hydroponic cultivation. The constant presence of viable B. cereus, however, emphasizes the fundamental importance of continuous risk assessment in case of any modifications or supplementations of the biofertilizer, since it clearly can act as a reservoir for bacterial endospores.
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| 7. |
- Larsson, Stefan, et al.
(författare)
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Effects of muscle lipid concentration on wild and hatchery brown trout (Salmo trutta) smolt migration
- 2012
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Ingår i: Canadian Journal of Fisheries and Aquatic Sciences. - 0706-652X .- 1205-7533. ; 69:1, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- Annually, hatchery programs are releasing millions of salmonid smolts into the Baltic Sea. Recent estimations indicate a decline in smolt sea survival, questioning the ecological and socioeconomic values of these programs. Concurrently, hatchery smolts have increased in lipid concentration. Salmonids display partial migration, and it is suggested that the ratio of migrants/residents is affected by individual smolt energetic status. To test whether the increased energetic status of hatchery smolts could explain the noted decrease in survival, we released wild trout smolts, conventional hatchery smolts, and hatchery smolts of low energetic status into a Baltic Sea river. Using telemetry, we obtained data on the number of successful migrants, their swimming speed, and diel migratory behaviour. A much lower proportion of conventional smolts (30%) successfully migrated to the coast. No difference was found between wild (74%) and hatchery smolts of low energetic status (64%). Furthermore, conventional smolts migrated slower and showed no diel migratory pattern. The results are of high relevance for hatchery programs producing partially migrating fish.
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| 8. |
- Serrano Gonzalez, Ignacio, et al.
(författare)
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Migration performance of wild and hatchery sea trout (Salmo trutta L.) smolts : implications for compensatory hatchery programs
- 2009
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Ingår i: Fisheries Research. - : Elsevier BV. - 0165-7836 .- 1872-6763. ; 9:3, s. 210-215
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Tidskriftsartikel (refereegranskat)abstract
- Migration success of hatchery-reared and wild sea trout smolts through the lower stretches and the estuary of a Baltic Sea river were studied. During 3 years, wild and hatchery trout smolts were implanted with acoustic transmitters and released 14 km upstream from the river mouth. In order to monitor their out-migration pattern, acoustic receivers were deployed along the migratory route. Data on number of fish detected and date and time of detections were analysed and the migratory performance of wild and hatchery-reared fish was compared. A significantly higher proportion of wild fish (80%) successfully migrated to the coast compared to fish of hatchery origin (27.5%) and migration was faster in wild smolts. Hatchery fish were larger and had a higher condition factor and lipid concentrations, which are proposed as possible reasons for the poorer migratory performance of the hatchery-reared fish.
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| 9. |
- Carrick, Christopher, et al.
(författare)
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Lightweight, Highly Compressible, Noncrystalline Cellulose Capsules
- 2014
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 30:26, s. 7635-7644
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate how to prepare extraordinarily deformable, gas-filled, spherical capsules from nonmodified cellulose. These capsules have a low nominal density, ranging from 7.6 to 14.2 kg/m(3), and can be deformed elastically to 70% deformation at 50% relative humidity. No compressive strain-at-break could be detected for these dry cellulose capsules, since they did not rupture even when compressed into a disk with pockets of highly compressed air. A quantitative constitutive model for the large deformation compression of these capsules is derived, including their high-frequency mechanical response and their low-frequency force relaxation, where the latter is governed by the gas barrier properties of the dry capsule. Mechanical testing corroborated these models with good accuracy. Force relaxation measurements at a constant compression rendered an estimate for the gas permeability of air through the capsule wall, calculated to 0.4 mL mu m/m(2) days kPa at 50% relative humidity. These properties taken together open up a large application area for the capsules, and they could most likely be used for applications in compressible, lightweight materials and also constitute excellent model materials for adsorption and adhesion studies.
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| 10. |
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