| 1. |
- Tuskan, G A, et al.
(författare)
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The genome of black cottonwood, Populus trichocarpa (Torr. & Gray).
- 2006
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 313:5793, s. 1596-604
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Tidskriftsartikel (refereegranskat)abstract
- We report the draft genome of the black cottonwood tree, Populus trichocarpa. Integration of shotgun sequence assembly with genetic mapping enabled chromosome-scale reconstruction of the genome. More than 45,000 putative protein-coding genes were identified. Analysis of the assembled genome revealed a whole-genome duplication event; about 8000 pairs of duplicated genes from that event survived in the Populus genome. A second, older duplication event is indistinguishably coincident with the divergence of the Populus and Arabidopsis lineages. Nucleotide substitution, tandem gene duplication, and gross chromosomal rearrangement appear to proceed substantially more slowly in Populus than in Arabidopsis. Populus has more protein-coding genes than Arabidopsis, ranging on average from 1.4 to 1.6 putative Populus homologs for each Arabidopsis gene. However, the relative frequency of protein domains in the two genomes is similar. Overrepresented exceptions in Populus include genes associated with lignocellulosic wall biosynthesis, meristem development, disease resistance, and metabolite transport.
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| 2. |
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| 3. |
- Haas, K., et al.
(författare)
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Influence of fish on habitat choice of water birds : A whole system experiment
- 2007
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Ingår i: Ecology. ; 88:11, s. 2915-2925
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Tidskriftsartikel (refereegranskat)abstract
- It is notoriously difficult to study population interactions among highly mobile animals that cannot be meaningfully confined to experimental plots of limited size. For example, migratory water birds are believed to suffer from competition with resident fish populations for shared food resources. While observational evidence in support of this hypothesis is accumulating, replicated experiments addressing this issue at the proper spatial scale are lacking. Here, we report from a replicated whole-system experiment in which we stocked large (0.07 km(2)), shallow (<= 2.5 m deep), highly eutrophic ponds in the bird protection area "Ismaninger Speichersee mit Fischteichen'' with different densities of carp and assessed the responses of water birds and their food resources during summer over several years. In all years, the biomasses of benthic macroinvertebrates, macroalgae, and macrophytes as well as the densities of herbivorous, carnivorous, and omnivorous water birds were reduced in carp ponds compared to fishshless ponds. The negative effects of carp on food resources and on the numbers of water birds feeding in carp ponds increased over the season (May-September) and were stronger at high than at low stocking densities of carp. Consequently, differences in resource densities between ponds with and without carp increased, and the ranking of ponds with respect to resource densities became more predictable over the season. These factors may have contributed to a seasonal improvement of the birds' abilities to track resource densities across ponds, as suggested by tight correlations of bird numbers on ponds with resource densities late, but not early, in the season.
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| 4. |
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| 5. |
- Petersen, AH, et al.
(författare)
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The effect of exercise on the absorption of inhaled human insulin in healthy volunteers
- 2008
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Ingår i: British Journal of Clinical Pharmacology. - : Wiley. - 1365-2125 .- 0306-5251. ; 65:2, s. 165-171
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Tidskriftsartikel (refereegranskat)abstract
- What is already known about this subject * Exercise is known to affect absorption of other inhaled substances, but so far there are no reports on the effect of exercise on the absorption of inhaled insulin in humans. What this paper adds * This report is the first to investigate the effect of exercise on the absorption of inhaled insulin. * In this study in healthy volunteers we found that exercise early after dosing increased absorption (15-20%) of inhaled insulin over the first 2 h after start of exercise, with an approximately 30% increase in maximal insulin concentration, and unchanged overall absorption. Aims To investigate the effect of moderate exercise on the absorption of inhaled insulin. Methods A single-centre, randomized, open-label, three-period cross-over trial was carried out in 12 nonsmoking healthy subjects. A dose of 3.5 mg inhaled human insulin was administered via a nebulizer and followed in random order by either 1) no exercise (NOEX), 2) 30 min exercise starting immediately after dosing (EX0), or 3) 30 min exercise starting 30 min after dosing (EX30). The study was carried out as a 10 h euglycaemic glucose clamp (90 mg dl(-1) (5.0 mmol l(-1))). Results The absorption of insulin over the first 2 h after start of exercise was 16% increased for EX0 (ratio (95%CI) 1.16 (1.04, 1.30), P = 0.01) and 20% increased for EX30 (1.20 (1.05, 1.36), P < 0.01), both compared with NOEX; the overall insulin absorption during 6 h and 10 h after dosing was not influenced by exercise. The maximum insulin concentration (C(max)) increased by 32% for EX0 and 35% for EX30 (both P < 0.01) compared with NOEX, while the time to C(max) was 31 min faster for EX0 (P < 0.01), but not significantly different after EX30, compared with NOEX. Conclusions A significant and clinically relevant increase of insulin absorption over the first 2 h after the beginning of exercise was observed. Until data from studies using the specific insulin inhalers exists, patients using inhaled insulin should be made aware of a potential increased absorption and higher concentration of insulin in connection with exercise.
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| 6. |
- Skogsberg, J., et al.
(författare)
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Transcriptional profiling uncovers a network of cholesterol-responsive atherosclerosis target genes
- 2008
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Ingår i: PLoS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 4:3
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Tidskriftsartikel (refereegranskat)abstract
- Despite the well-documented effects of plasma lipid lowering regimes halting atherosclerosis lesion development and reducing morbidity and mortality of coronary artery disease and stroke, the transcriptional response in the atherosclerotic lesion mediating these beneficial effects has not yet been carefully investigated. We performed transcriptional profiling at 10-week intervals in atherosclerosis-prone mice with human-like hypercholesterolemia and a genetic switch to lower plasma lipoproteins (Ldlr-/-Apo 100/100 Mttpflox/flox Mx1-Cre). Atherosclerotic lesions progressed slowly at first, then expanded rapidly, and plateaued after advanced lesions formed. Analysis of lesion expression profiles indicated that accumulation of lipid-poor macrophages reached a point that led to the rapid expansion phase with accelerated foam-cell formation and inflammation, an interpretation supported by lesion histology. Genetic lowering of plasma cholesterol (e.g., lipoproteins) at this point all together prevented the formation of advanced plaques and parallel transcriptional profiling of the atherosclerotic arterial wall identified 37 cholesterol-responsive genes mediating this effect. Validation by siRNA-inhibition in macrophages incubated with acetylated-LDL revealed a network of eight cholesterol-responsive atherosclerosis genes regulating cholesterol-ester accumulation. Taken together, we have identified a network of atherosclerosis genes that in response to plasma cholesterol-lowering prevents the formation of advanced plaques. This network should be of interest for the development of novel atherosclerosis therapies. © 2008 Skogsberg et al.
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| 8. |
- Felten, Judith, et al.
(författare)
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The ectomycorrhizal fungus laccaria bicolor stimulates lateral root formation in poplar and arabidopsis through auxin transport and signaling
- 2009
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Ingår i: Plant Physiology. - Rockville : American society of plant biologists. - 0032-0889 .- 1532-2548. ; 151:4, s. 1991-2005
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Tidskriftsartikel (refereegranskat)abstract
- The early phase of the interaction between tree roots and ectomycorrhizal fungi, prior to symbiosis establishment, is accompanied by a stimulation of lateral root (LR) development. We aimed to identify gene networks that regulate LR development during the early signal exchanges between poplar (Populus tremula x Populus alba) and the ectomycorrhizal fungus Laccaria bicolor with a focus on auxin transport and signaling pathways. Our data demonstrated that increased LR development in poplar and Arabidopsis (Arabidopsis thaliana) interacting with L. bicolor is not dependent on the ability of the plant to form ectomycorrhizae. LR stimulation paralleled an increase in auxin accumulation at root apices. Blocking plant polar auxin transport with 1-naphthylphthalamic acid inhibited LR development and auxin accumulation. An oligoarray-based transcript profile of poplar roots exposed to molecules released by L. bicolor revealed the differential expression of 2,945 genes, including several components of polar auxin transport (PtaPIN and PtaAUX genes), auxin conjugation (PtaGH3 genes), and auxin signaling (PtaIAA genes). Transcripts of PtaPIN9, the homolog of Arabidopsis AtPIN2, and several PtaIAAs accumulated specifically during the early interaction phase. Expression of these rapidly induced genes was repressed by 1-naphthylphthalamic acid. Accordingly, LR stimulation upon contact with L. bicolor in Arabidopsis transgenic plants defective in homologs of these genes was decreased or absent. Furthermore, in Arabidopsis pin2, the root apical auxin increase during contact with the fungus was modified. We propose a model in which fungus-induced auxin accumulation at the root apex stimulates LR formation through a mechanism involving PtaPIN9-dependent auxin redistribution together with PtaIAA-based auxin signaling.
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| 9. |
- Gustafson, Johan, et al.
(författare)
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Structure of a thin oxide film on Rh(100)
- 2005
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Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 71:11
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Tidskriftsartikel (refereegranskat)abstract
- The initial oxidation of Rh(100) has been studied using high resolution core level spectroscopy, low energy electron diffraction, surface x-ray diffraction, scanning tunneling microscopy, and density functional theory. We report a structural study of an oxygen induced structure displaying a c(8x2) periodicity at an oxygen pressure above 10(-5) mbar and using a sample temperature of 700 K. Our experimental and theoretical data demonstrate that this structure is due to the formation of a thin surface oxide with a hexagonal trilayer O-Rh-O structure.
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| 10. |
- Kohler, A, et al.
(författare)
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Reducing inter-replicate variation in fourier transform infrared spectroscopy by extended multiplicative signal correction.
- 2009
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Ingår i: Applied spectroscopy. - 0003-7028. ; 63:3, s. 296-305
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Tidskriftsartikel (refereegranskat)abstract
- Fourier transform infrared (FT-IR) spectroscopy is a powerful tool for characterizing biological tissues and organisms, but it is plagued by replicate variation of various sources. Here, a method for estimating and correcting unwanted replicate variation in multivariate measurement signals, based on extended multiplicative signal correction (EMSC), is presented. Systematic patterns of unwanted methodological variations are estimated from replicate spectra, modeled by a linear subspace model, and implemented into EMSC. The method is applied to FT-IR spectra of two different sets of microorganisms (different double gene knockout strains of Saccharomyces cerevisiae and different species of Listeria) and compared to other preprocessing methods used in FT-IR absorption spectroscopy of microorganisms. The EMSC replicate correction turns out to perform best among the compared methods.
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