| 1. |
- Myers-Smith, Isla H., et al.
(författare)
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Complexity revealed in the greening of the Arctic
- 2020
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Ingår i: Nature Climate Change. - : Springer Science and Business Media LLC. - 1758-678X .- 1758-6798. ; 10:2, s. 106-117
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Tidskriftsartikel (refereegranskat)abstract
- As the Arctic warms, vegetation is responding, and satellite measures indicate widespread greening at high latitudes. This ‘greening of the Arctic’ is among the world’s most important large-scale ecological responses to global climate change. However, a consensus is emerging that the underlying causes and future dynamics of so-called Arctic greening and browning trends are more complex, variable and inherently scale-dependent than previously thought. Here we summarize the complexities of observing and interpreting high-latitude greening to identify priorities for future research. Incorporating satellite and proximal remote sensing with in-situ data, while accounting for uncertainties and scale issues, will advance the study of past, present and future Arctic vegetation change.
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| 2. |
- Schoch, Conrad L., et al.
(författare)
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Finding needles in haystacks: linking scientific names, reference specimens and molecular data for Fungi
- 2014
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Ingår i: Database: The Journal of Biological Databases and Curation. - : Oxford University Press (OUP). - 1758-0463. ; 2014:bau061, s. 1-21
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Tidskriftsartikel (refereegranskat)abstract
- DNA phylogenetic comparisons have shown that morphology-based species recognition often underestimates fungal diversity. Therefore, the need for accurate DNA sequence data, tied to both correct taxonomic names and clearly annotated specimen data, has never been greater. Furthermore, the growing number of molecular ecology and microbiome projects using high-throughput sequencing require fast and effective methods for en masse species assignments. In this article, we focus on selecting and re-annotating a set of marker reference sequences that represent each currently accepted order of Fungi. The particular focus is on sequences from the internal transcribed spacer region in the nuclear ribosomal cistron, derived from type specimens and/or ex-type cultures. Re-annotated and verified sequences were deposited in a curated public database at the National Center for Biotechnology Information (NCBI), namely the RefSeq Targeted Loci (RTL) database, and will be visible during routine sequence similarity searches with NR_prefixed accession numbers. A set of standards and protocols is proposed to improve the data quality of new sequences, and we suggest how type and other reference sequences can be used to improve identification of Fungi.
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| 3. |
- Mousavy Gharavy, S. Neda, et al.
(författare)
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Sexually dimorphic roles for the type 2 diabetes-associated C2cd4b gene in murine glucose homeostasis
- 2021
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Ingår i: Diabetologia. - : Springer Nature. - 0012-186X .- 1432-0428. ; 64:4, s. 850-864
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Tidskriftsartikel (refereegranskat)abstract
- Aims/hypothesis Variants close to the VPS13C/C2CD4A/C2CD4B locus are associated with altered risk of type 2 diabetes in genome-wide association studies. While previous functional work has suggested roles for VPS13C and C2CD4A in disease development, none has explored the role of C2CD4B. Methods CRISPR/Cas9-induced global C2cd4b-knockout mice and zebrafish larvae with c2cd4a deletion were used to study the role of this gene in glucose homeostasis. C2 calcium dependent domain containing protein (C2CD)4A and C2CD4B constructs tagged with FLAG or green fluorescent protein were generated to investigate subcellular dynamics using confocal or near-field microscopy and to identify interacting partners by mass spectrometry. Results Systemic inactivation of C2cd4b in mice led to marked, but highly sexually dimorphic changes in body weight and glucose homeostasis. Female C2cd4b mice displayed unchanged body weight compared with control littermates, but abnormal glucose tolerance (AUC, p = 0.01) and defective in vivo, but not in vitro, insulin secretion (p = 0.02). This was associated with a marked decrease in follicle-stimulating hormone levels as compared with wild-type (WT) littermates (p = 0.003). In sharp contrast, male C2cd4b null mice displayed essentially normal glucose tolerance but an increase in body weight (p < 0.001) and fasting blood glucose (p = 0.003) after maintenance on a high-fat and -sucrose diet vs WT littermates. No metabolic disturbances were observed after global inactivation of C2cd4a in mice, or in pancreatic beta cell function at larval stages in C2cd4a null zebrafish. Fasting blood glucose levels were also unaltered in adult C2cd4a-null fish. C2CD4B and C2CD4A were partially localised to the plasma membrane, with the latter under the control of intracellular Ca2+. Binding partners for both included secretory-granule-localised PTPRN2/phogrin. Conclusions/interpretation Our studies suggest that C2cd4b may act centrally in the pituitary to influence sex-dependent circuits that control pancreatic beta cell function and glucose tolerance in rodents. However, the absence of sexual dimorphism in the impact of diabetes risk variants argues for additional roles for C2CD4A or VPS13C in the control of glucose homeostasis in humans. Data availability The datasets generated and/or analysed during the current study are available in the Biorxiv repository (www. biorxiv.org/content/10.1101/2020.05.18.099200v1). RNA-Seq (GSE152576) and proteomics (PXD021597) data have been deposited to GEO (www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE152576) and ProteomeXchange (www.ebi.ac.uk/pride/ archive/projects/PXD021597) repositories, respectively.
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| 4. |
- How, Penny, et al.
(författare)
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Rapidly changing subglacial hydrological pathways at a tidewater glacier revealed through simultaneous observations of water pressure, supraglacial lakes, meltwater plumes and surface velocities
- 2017
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Ingår i: The Cryosphere. - : Copernicus GmbH. - 1994-0416 .- 1994-0424. ; 11, s. 2691-2710
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Tidskriftsartikel (refereegranskat)abstract
- Subglacial hydrological processes at tidewater glaciers remain poorly understood due to the difficulty in obtaining direct measurements and lack of empirical verification for modelling approaches. Here, we investigate the subglacial hydrology of Kronebreen, a fast-flowing tidewater glacier in Svalbard during the 2014 melt season. We combine observations of borehole water pressure, supraglacial lake drainage, surface velocities and plume activity with modelled run-off and water routing to develop a conceptual model that thoroughly encapsulates subglacial drainage at a tidewater glacier. Simultaneous measurements suggest that an earlyseason episode of subglacial flushing took place during our observation period, and a stable efficient drainage system effectively transported subglacial water through the northern region of the glacier tongue. Drainage pathways through the central and southern regions of the glacier tongue were disrupted throughout the following melt season. Periodic plume activity at the terminus appears to be a signal for modulated subglacial pulsing, i.e. an internally driven storage and release of subglacial meltwater that operates independently of marine influences. This storage is a key control on ice flow in the 2014 melt season. Evidence from this work and previous studies strongly suggests that long-term changes in ice flow at Kronebreen are controlled by the location of efficient/inefficient drainage and the position of regions where water is stored and released.
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| 5. |
- Mitrofanova, A, et al.
(författare)
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SMPDL3b modulates insulin receptor signaling in diabetic kidney disease
- 2019
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Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10:1, s. 2692-
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Tidskriftsartikel (refereegranskat)abstract
- Sphingomyelin phosphodiesterase acid-like 3b (SMPDL3b) is a lipid raft enzyme that regulates plasma membrane (PM) fluidity. Here we report that SMPDL3b excess, as observed in podocytes in diabetic kidney disease (DKD), impairs insulin receptor isoform B-dependent pro-survival insulin signaling by interfering with insulin receptor isoforms binding to caveolin-1 in the PM. SMPDL3b excess affects the production of active sphingolipids resulting in decreased ceramide-1-phosphate (C1P) content as observed in human podocytes in vitro and in kidney cortexes of diabetic db/db mice in vivo. Podocyte-specific Smpdl3b deficiency in db/db mice is sufficient to restore kidney cortex C1P content and to protect from DKD. Exogenous administration of C1P restores IR signaling in vitro and prevents established DKD progression in vivo. Taken together, we identify SMPDL3b as a modulator of insulin signaling and demonstrate that supplementation with exogenous C1P may represent a lipid therapeutic strategy to treat diabetic complications such as DKD.
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| 6. |
- Bryn, V., et al.
(författare)
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Brain derived neurotrophic factor (BDNF) and autism spectrum disorders (ASD) in childhood
- 2015
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Ingår i: European Journal of Paediatric Neurology. - : Elsevier BV. - 1090-3798. ; 19:4, s. 411-414
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Tidskriftsartikel (refereegranskat)abstract
- Background: Neurotrophic factors are essential regulators of neuronal maturation including synaptic synthesis. Among those, Brain derived neurotrophic factor (BDNF) has been in particular focus in the understanding of autism spectrum disorders (ASD). Purpose: The aim of our study was to investigate whether BNDF could be used as diagnostic/biological marker for ASD. For this purpose we examined the plasma levels of BDNF and the precursors pro- BDNF in patients with ASD and compared it with non-autistic controls; determined whether there was a correlation between the BDNF and proBDNF levels and clinical severity. We also investigated the coding region of BDNF identify for well-variations which could be associated to ASD. Methods: The 65 ASD patients (51 boys) were enrolled from a recent completed epidemiological survey covering two counties (Oppland and Hedmark) in Norway. The mean age of the total number of children who participated in this study was 11,7 years. 30 non-autistic children were included as controls, 14 boys and 16 girls. The mean age was 11.3 years. Exclusion criteria for control group were individuals suffering from either neurological, endocrine, or immune insuffiency. Results and conclusions: Patients with ASD were characterized by moderately but significantly elevated plasma levels of BDNF compared to matched controls. No differences were observed in the proBDNF level between patients and controls. Within the ASD group, children with intellectual disability demonstrated increased BDNF, but not proBDNF levels, while the presence of ADHD had no impact on circulating proBDNF or BDNF. No further associations between plasma proBDNF or BDNF and other clinical demographics were observed. (C) 2015 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.
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| 7. |
- Bryn, V., et al.
(författare)
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Cytokine Profile in Autism Spectrum Disorders in Children
- 2017
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Ingår i: Journal of Molecular Neuroscience. - : Springer Science and Business Media LLC. - 0895-8696 .- 1559-1166. ; 61:1, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- The pathogenesis of autism spectrum disorders (ASD) is not completely understood, but there is evidence of associations with altered immune responses. The aim of this study was to determine the serum levels of various cytokines in children with ASD and in healthy controls, in order to determine their role in ASD and its diagnostic subgroups. Sixty-five ASD patients were enrolled from an epidemiological survey in Norway, of which 30 were diagnosed with childhood autism, 16 with Asperger syndrome, 12 with atypical autism, 1 with Rett syndrome, and 6 with another ASD diagnosis. The serum levels of 12 cytokines were measured in all of the patients and in 30 healthy children. The cytokine levels did not differ significantly between the ASD group and the healthy controls. However, the interleukin-8 (IL-8) level was significantly higher (6.82 vs 4.58 pg/ml, p = 0.017) while that of IL-10 was significantly lower (2.24 vs 6.49 pg/ml, p = 0.009) in patients with childhood autism than in controls. Furthermore, the IL-8 level was significantly higher in childhood autism than in Asperger syndrome (6.82 vs 4.05 pg/ml, p = 0.013). Our study shows that the cytokine profile of children diagnosed with ASD, regardless of the subdiagnosis, does not differ from healthy controls. However, differentiation into different diagnostic subgroups reveals significantly different levels of IL-8 and IL-10. This indicates that different mechanisms may underlie the different ASD subdiagnoses. Future research into the pathophysiological mechanisms of ASD should pay more attention to the different subdiagnoses of ASD.
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| 8. |
- Doyle, Samuel H., et al.
(författare)
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Amplified melt and flow of the Greenland ice sheet driven by late-summer cyclonic rainfall
- 2015
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Ingår i: Nature Geoscience. - 1752-0894 .- 1752-0908. ; 8:8, s. 647-
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Tidskriftsartikel (refereegranskat)abstract
- Intense rainfall events significantly affect Alpine and Alaskan glaciers through enhanced melting, ice-flow acceleration and subglacial sediment erosion, yet their impact on the Greenland ice sheet has not been assessed. Here we present measurements of ice velocity, subglacial water pressure and meteorological variables from the western margin of the Greenland ice sheet during a week of warm, wet cyclonic weather in late August and early September 2011. We find that extreme surface runoff from melt and rainfall led to a widespread acceleration in ice flow that extended 140 km into the ice-sheet interior. We suggest that the late-season timing was critical in promoting rapid runoff across an extensive bare ice surface that overwhelmed a subglacial hydrological system in transition to a less-efficient winter mode. Reanalysis data reveal that similar cyclonic weather conditions prevailed across southern and western Greenland during this time, and we observe a corresponding ice-flow response at all land- and marine-terminating glaciers in these regions for which data are available. Given that the advection of warm, moist air masses and rainfall over Greenland is expected to become more frequent in the coming decades, our findings portend a previously unforeseen vulnerability of the Greenland ice sheet to climate change.
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| 9. |
- Keetz, Lasse T., et al.
(författare)
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Climate–ecosystem modelling made easy : The Land Sites Platform
- 2023
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Ingår i: Global Change Biology. - 1354-1013. ; 29:15, s. 4440-4452
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Tidskriftsartikel (refereegranskat)abstract
- Dynamic Global Vegetation Models (DGVMs) provide a state-of-the-art process-based approach to study the complex interplay between vegetation and its physical environment. For example, they help to predict how terrestrial plants interact with climate, soils, disturbance and competition for resources. We argue that there is untapped potential for the use of DGVMs in ecological and ecophysiological research. One fundamental barrier to realize this potential is that many researchers with relevant expertize (ecology, plant physiology, soil science, etc.) lack access to the technical resources or awareness of the research potential of DGVMs. Here we present the Land Sites Platform (LSP): new software that facilitates single-site simulations with the Functionally Assembled Terrestrial Ecosystem Simulator, an advanced DGVM coupled with the Community Land Model. The LSP includes a Graphical User Interface and an Application Programming Interface, which improve the user experience and lower the technical thresholds for installing these model architectures and setting up model experiments. The software is distributed via version-controlled containers; researchers and students can run simulations directly on their personal computers or servers, with relatively low hardware requirements, and on different operating systems. Version 1.0 of the LSP supports site-level simulations. We provide input data for 20 established geo-ecological observation sites in Norway and workflows to add generic sites from public global datasets. The LSP makes standard model experiments with default data easily achievable (e.g., for educational or introductory purposes) while retaining flexibility for more advanced scientific uses. We further provide tools to visualize the model input and output, including simple examples to relate predictions to local observations. The LSP improves access to land surface and DGVM modelling as a building block of community cyberinfrastructure that may inspire new avenues for mechanistic ecosystem research across disciplines.
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| 10. |
- Ormstad, H., et al.
(författare)
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Serum Tryptophan, Tryptophan Catabolites and Brain-derived Neurotrophic Factor in Subgroups of Youngsters with Autism Spectrum Disorders
- 2018
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Ingår i: Cns & Neurological Disorders-Drug Targets. - : Bentham Science Publishers Ltd.. - 1871-5273. ; 17:8, s. 626-639
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Tidskriftsartikel (refereegranskat)abstract
- Background: There is evidence that changes in neuro-immune responses coupled with dysfunctions in serotonin metabolism underpin the pathophysiology of autism spectrum disorders (ASD). Objective: This study aimed to delineate whether ASD subgroups or characteristics show aberrations in tryptophan and brain-derived neurotrophic factor (BDNF) metabolism. Methods: 65 individuals with ASD (diagnosed according to ICD criteria) and 30 healthy control patients were included. Measured were serum levels of tryptophan, kynurenine (KYN), kynurenic acid (KA), quinolinic acid (QA), BDNF and PRO-BDNF and total blood 5-HT and 5-OH-tryptophan (5-HTP). Results: Elevated BDNF levels and lower tryptophan and KA levels were characteristics of both childhood autism and intellectual disability disorder, whilst elevated tryptophan and lower 5-HT synthesis were hallmarks of Asperger syndrome. A pathological MRI was associated with elevated tryptophan and lowered KA. Abnormal EEG results and dysmorphology were both associated with an elevated BDNF/ PRO-BDNF ratio. Any brain pathology and gastro-intestinal symptoms were accompanied by lowered KA. Conclusions: Increased BDNF production and changes in the metabolism of tryptophan are associated with many ASD characteristics, showing particularly strong associations with childhood autism and Intellectual and Developmental Disabilities. Peripheral BDNF and tryptophan metabolism appear to take part in the pathophysiology of autism spectrum disorders and their phenotypes.
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