| 1. |
- Eklund, D. Magnus, et al.
(författare)
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Homologues of the Arabidopsis thaliana SHI/STY/LRP1 genes control auxin biosynthesis and affect growth and development in the moss Physcomitrella patens
- 2010
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Ingår i: Development. - : The Company of Biologists. - 0950-1991 .- 1477-9129. ; 137:8, s. 1275-1284
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Tidskriftsartikel (refereegranskat)abstract
- The plant hormone auxin plays fundamental roles in vascular plants. Although exogenous auxin also stimulates developmental transitions and growth in non-vascular plants, the effects of manipulating endogenous auxin levels have thus far not been reported. Here, we have altered the levels and sites of auxin production and accumulation in the moss Physcomitrella patens by changing the expression level of homologues of the Arabidopsis SHI/STY family proteins, which are positive regulators of auxin biosynthesis genes. Constitutive expression of PpSHI1 resulted in elevated auxin levels, increased and ectopic expression of the auxin response reporter GmGH3pro:GUS, and in an increased caulonema/chloronema ratio, an effect also induced by exogenous auxin application. In addition, we observed premature ageing and necrosis in cells ectopically expressing PpSHI1. Knockout of either of the two PpSHI genes resulted in reduced auxin levels and auxin biosynthesis rates in leafy shoots, reduced internode elongation, delayed ageing, a decreased caulonema/chloronema ratio and an increased number of axillary hairs, which constitute potential auxin biosynthesis sites. Some of the identified auxin functions appear to be analogous in vascular and non-vascular plants. Furthermore, the spatiotemporal expression of the PpSHI genes and GmGH3pro:GUS strongly overlap, suggesting that local auxin biosynthesis is important for the regulation of auxin peak formation in non-vascular plants.
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| 2. |
- Hederström, Veronica, et al.
(författare)
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White clover pollinators and seed set in relation to local management and landscape context
- 2024
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Ingår i: Agriculture, Ecosystems and Environment. - 0167-8809 .- 1873-2305. ; 365
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Tidskriftsartikel (refereegranskat)abstract
- Bees are declining, which is worrisome since they both have intrinsic conservation value and play a major role as pollinators in both natural and managed ecosystems. Land use change and lack of suitable habitats are often suggested as driving forces of bee decline. To propose mitigation measures to halt bee decline, it is important to understand how land use relates to bee abundance and diversity, and to explore consequences for their provision of pollination services. White clover, Trifolium repens, is an outcrossing mass-flowering crop, which could serve as an abundant, although ephemeral, food resource for bees. We investigated how the bee community in 39 fields of white clover grown for seed, related to local field management (organic, conventional without insecticides and conventional with insecticides) and landscape context (proportion semi-natural land), and how this pollinator community related to white clover seed set. The honey bee, Apis mellifera, was the most commonly observed bee species, and two generalist bumble bee species, Bombus terrestris and B. lapidarius, were the subsequently most common. We observed fewer non-Apis bees, and a lower bee species richness in organic white clover seed fields compared to conventional fields independent of insecticide treatment. Bee species richness in both conventional and organic fields were positively related to the proportion of semi-natural land in the landscape, likely because of a larger species pool in such landscapes. Initial seed set in immature inflorescences was positively related to bee abundance, whereas final seed set in mature inflorescences was unrelated to bee abundance, possibly as a consequence of seed-eating weevils consuming a large proportion of the seeds. We conclude that both bee visitation and seed set in white clover benefit from conventional management and that landscapes rich in semi-natural habitats will make future crop production more resilient. The observed positive relationship between bee abundance and initial seed set suggests that if we can mitigate pest impacts and increase bee abundance in clover seed fields, the final seed yield can be increased. Thus, bee decline should be considered and mitigated both to maintain biodiversity in general and for crop seed production specifically.
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| 3. |
- Olsson, Jörgen, et al.
(författare)
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Landscape and substrate properties affect species richness and community composition of saproxylic beetles
- 2012
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Ingår i: Forest Ecology and Management. - : Elsevier. - 0378-1127 .- 1872-7042. ; 286, s. 108-120
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Tidskriftsartikel (refereegranskat)abstract
- Intensive forest management has dramatically reduced the area of old-growth forest in Fennoscandia. We examined if the proportion of old forest in a landscape affects species composition, richness and abundance of saproxylic beetles. We used tube-shaped window traps in five pairs of sites, selected so that the sites within each pair differed with respect to the proportion of old forest (>125 years) in the surrounding landscape. A landscape level inventory of the wood fungi Fomitopsis rosea, as a proxy for forest with high conservation values, was used to complement the data on old forests. In addition, to testing whether mycelia-colonised wood may attract saproxylic beetles, the tube-shaped window traps were baited with wood colonised by Fomitopsis pinicola or F. rosea. Old-forest-rich landscapes supported significantly more species and a higher abundance of saproxylic beetles than old-forest-poor landscapes. The analysis revealed a clear connection between the community composition of saproxylic beetles and the proportion of old forest and number of F. rosea fruiting bodies in the surrounding landscape (radius 3 km). The local landscape species pool thus appears to be important for the beetle species that are trapped since the composition of saproxylic beetles differed between the two landscape types. The effects of the different baits were less pronounced than the effect of landscape type, although species-specific responses to the two mycelia baits were observed. This indicates that volatiles from mycelia of wood-decaying fungi and the mycelial community may affect colonisation patterns of saproxylic beetles. Our results suggest that forest fragmentation and habitat loss have resulted in depauperate beetle faunas in old-forest-poor landscapes. Our results highlight the need to invoke a landscape scale approach for preserving biodiversity, in this case the need to maintain a sufficient proportion of forest with old growth characteristics in the managed landscape.
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| 4. |
- Persson, Erik, 1972-, et al.
(författare)
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Very Low Energy High Yield Pulping
- 2022
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Ingår i: Proceedings of the International Mechanical Pulping Conference. ; , s. 41-46
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The project goal was to efficiently separate spruce fibers with preserved fiber stiffness and a low content of unsepa-rated fibers (shive content max~1%) using minimal amounts of electricity. The project tested process variants based on the .HT-CTMP-process concept. Above room temperature, the mechanical properties of water saturated wood are pri-marily determined by the lignin, which softens with increas-ing temperature and water content. The lignin is not evenly distributed in the wood structure, and the pattern of fiber separation in wood will therefore to a large extent be de-pendent on the properties of the lignin. The relative softening temperature increases with increasing strain rate. In me-chanical defibration at temperatures below the lignin soften-ing temperature, a large proportion of the fibers will frac-ture across the fiber direction. At elevated temperatures, above the lignin softening interval, an increasing proportion of the fibers will be separated in the middle lamella along the fiber axis, i.e. with a higher fiber separation selectivity. Sulfonation of wood reduces the degree of crosslinking in lignin and increases the charge. The structural change makes the wood softer at a certain temperature. In a pilot trial Norway spruce (Picea abies (L.) Karst.) chips were re-fined at 130, 160 or 180 degrees C after impregnation with 25 or 50 kg/ton sodium sulfite in a pH range from 4,5 to 12. The temperature was the most important factor affecting the shives/energy relation. The sulfite charge and the pH-level also affect the results, but less than the temperature within the evaluated range. The results show there is a potential to produce pulps with a shive content of about 1% using less than 200 kWh/ton at 180 °C in the pre-heater and inlet of the refiner. Producing a high yield, fiber material with pre-served fiber dimensions and low content of shives using a few hundred kWh/ton opens for new opportunities both in paper and board production, but also in new applications where the bonding between fibers is achieved by other means than in traditional paper and paperboard products.
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| 5. |
- Rönnberg, Jonas, et al.
(författare)
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Incidence of Heterobasidion spp. following different thinning regimes in Norway spruce in southern Sweden
- 2013
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 289, s. 409-415
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Tidskriftsartikel (refereegranskat)abstract
- The incidence of Heterobasidion spp. infections following different thinning regimes in Norway spruce was evaluated on 12 plots in a trial in southern Sweden. The plots were established in 1961 and followed until final felling in 2001. The treatments ranged from one light thinning at the experimental set-up to six thinnings. The average incidence of decay was 44% across all thinning regimes of which Heterobasidion spp. was identified in 85% of the cases. There was no difference in the incidence of infections, decayed volumes, and the size or number of Heterobasidion spp. genets among the thinning regimes. The largest genet was though found on the plot with just one light thinning and encompassed 25 trees. On average, 11.1% of the stem volume was decayed and the average height of the decay column was 4 m. Decay incidence was 3.7 times the decayed volume and the height of the decay columns was 19 times the diameter of the decay at stump height. Conclusively, early thinning appears to be more important for disease development than subsequent multiple thinning. To restrict the disease development in the stand later during the rotation period, it is of utmost importance that the earlier thinnings are made during winter conditions or otherwise properly protected against spore infection of Heterobasidion. (C) 2012 Elsevier B.V. All rights reserved.
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| 6. |
- Zhu, Yajing, et al.
(författare)
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The role of serum thymidine kinase 1 activity in neoadjuvant-treated HER2-positive breast cancer : biomarker analysis from the Swedish phase II randomized PREDIX HER2 trial
- 2024
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Ingår i: Breast Cancer Research and Treatment. - : Springer. - 0167-6806 .- 1573-7217. ; 204:2, s. 299-308
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundThymidine kinase 1 (TK1) plays a pivotal role in DNA synthesis and cellular proliferation. TK1 has been studied as a prognostic marker and as an early indicator of treatment response in human epidermal growth factor 2 (HER2)-negative early and metastatic breast cancer (BC). However, the prognostic and predictive value of serial TK1 activity in HER2-positive BC remains unknown.MethodsIn the PREDIX HER2 trial, 197 HER2-positive BC patients were randomized to neoadjuvant trastuzumab, pertuzumab, and docetaxel (DPH) or trastuzumab emtansine (T-DM1), followed by surgery and adjuvant epirubicin and cyclophosphamide. Serum samples were prospectively collected from all participants at multiple timepoints: at baseline, after cycle 1, 2, 4, and 6, at end of adjuvant therapy, annually for a total period of 5 years and/or at the time of recurrence. The associations of sTK1 activity with baseline characteristics, pathologic complete response (pCR), event-free survival (EFS), and disease-free survival (DFS) were evaluated.ResultsNo association was detected between baseline sTK1 levels and all the baseline clinicopathologic characteristics. An increase of TK1 activity from baseline to cycle 2 was seen in all cases. sTK1 level at baseline, after 2 and 4 cycles was not associated with pCR status. After a median follow-up of 58 months, 23 patients had EFS events. There was no significant effect between baseline or cycle 2 sTK1 activity and time to event. A non-significant trend was noted among patents with residual disease (non-pCR) and high sTK1 activity at the end of treatment visit, indicating a potentially worse long-term prognosis.ConclusionsTK1 activity increased following neoadjuvant therapy for HER2-positive BC but was not associated with patient outcomes or treatment benefit. However, the post-surgery prognostic value in patients that have not attained pCR warrants further investigation.Trial registrationClinicalTrials.gov, NCT02568839. Registered on 6 October 2015.
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