| 1. |
- Aho, Seppo, et al.
(författare)
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Tourism : history
- 2016
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Ingår i: Encyclopedia of the Barents Region. - Oslo : Pax Forlag. - 9788253038599 ; , s. 401-400
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Bokkapitel (refereegranskat)
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| 2. |
- Aho, Seppo, et al.
(författare)
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Tourism in the Barents Region
- 2016
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Ingår i: Encyclopedia of the Barents Region. - Oslo : Pax Forlag. - 9788253038599 ; , s. 395-400
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Bokkapitel (refereegranskat)
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| 3. |
- Bergström, Anders, et al.
(författare)
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Grey wolf genomic history reveals a dual ancestry of dogs
- 2022
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 607:7918, s. 313-320
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Tidskriftsartikel (refereegranskat)abstract
- The grey wolf (Canis lupus) was the first species to give rise to a domestic population, and they remained widespread throughout the last Ice Age when many other large mammal species went extinct. Little is known, however, about the history and possible extinction of past wolf populations or when and where the wolf progenitors of the present-day dog lineage (Canis familiaris) lived. Here we analysed 72 ancient wolf genomes spanning the last 100,000 years from Europe, Siberia and North America. We found that wolf populations were highly connected throughout the Late Pleistocene, with levels of differentiation an order of magnitude lower than they are today. This population connectivity allowed us to detect natural selection across the time series, including rapid fixation of mutations in the gene IFT88 40,000–30,000 years ago. We show that dogs are overall more closely related to ancient wolves from eastern Eurasia than to those from western Eurasia, suggesting a domestication process in the east. However, we also found that dogs in the Near East and Africa derive up to half of their ancestry from a distinct population related to modern southwest Eurasian wolves, reflecting either an independent domestication process or admixture from local wolves. None of the analysed ancient wolf genomes is a direct match for either of these dog ancestries, meaning that the exact progenitor populations remain to be located.
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| 4. |
- Marques, André R A, et al.
(författare)
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Glucosylated cholesterol in mammalian cells and tissues: formation and degradation by multiple cellular β-glucosidases.
- 2016
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Ingår i: Journal of Lipid Research. - 1539-7262. ; 57, s. 451-463
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Tidskriftsartikel (refereegranskat)abstract
- The membrane lipid glucosylceramide (GlcCer) is continuously formed and degraded. Cells express two GlcCer-degrading β-glucosidases, GBA and GBA2, located in and outside the lysosome, respectively. Here we demonstrate that through transglucosylation both GBA and GBA2 are able to catalyze in vitro the transfer of glucosyl-moieties from GlcCer to cholesterol, and vice versa. Furthermore, the natural occurrence of 1-O-cholesteryl-β-D-glucopyranoside (GlcChol) in mouse tissues and human plasma is demonstrated using LC-MS/MS and 13C6-labelled GlcChol as internal standard. In cells the inhibition of GBA increases GlcChol, whereas inhibition of GBA2 decreases glucosylated sterol. Similarly, in GBA2-deficient mice GlcChol is reduced. Depletion of GlcCer by inhibition of GlcCer synthase decreases GlcChol in cells and likewise in plasma of inhibitor-treated Gaucher disease patients. In tissues of mice with Niemann-Pick type C, a condition characterized by intralysosomal accumulation of cholesterol, marked elevations in GlcChol occur as well. When lysosomal accumulation of cholesterol is induced in cultured cells, GlcChol is formed via lysosomal GBA. This illustrates that reversible transglucosylation reactions are highly dependent on local availability of suitable acceptors. In conclusion, mammalian tissues contain GlcChol formed by transglucosylation through β-glucosidases using GlcCer as donor. Our findings reveal a novel metabolic function for GlcCer.
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| 5. |
- Palkopoulou, Eleftheria, et al.
(författare)
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Synchronous genetic turnovers across Western Eurasia in Late Pleistocene collared lemmings
- 2016
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 22:5, s. 1710-1721
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Tidskriftsartikel (refereegranskat)abstract
- Recent palaeogenetic studies indicate a highly dynamic history in collared lemmings (Dicrostonyx spp.), with several demographical changes linked to climatic fluctuations that took place during the last glaciation. At the western range margin of D.torquatus, these changes were characterized by a series of local extinctions and recolonizations. However, it is unclear whether this pattern represents a local phenomenon, possibly driven by ecological edge effects, or a global phenomenon that took place across large geographical scales. To address this, we explored the palaeogenetic history of the collared lemming using a next-generation sequencing approach for pooled mitochondrial DNA amplicons. Sequences were obtained from over 300 fossil remains sampled across Eurasia and two sites in North America. We identified five mitochondrial lineages of D.torquatus that succeeded each other through time across Europe and western Russia, indicating a history of repeated population extinctions and recolonizations, most likely from eastern Russia, during the last 50000years. The observation of repeated extinctions across such a vast geographical range indicates large-scale changes in the steppe-tundra environment in western Eurasia during the last glaciation. AllHolocene samples, from across the species' entire range, belonged to only one of the five mitochondrial lineages. Thus, extant D.torquatus populations only harbour a small fraction of the total genetic diversity that existed across different stages of the Late Pleistocene. In North American samples, haplotypes belonging to both D.groenlandicus and D.richardsoni were recovered from a Late Pleistocene site in south-western Canada. This suggests that D.groenlandicus had a more southern and D.richardsoni a more northern glacial distribution than previously thought. This study provides significant insights into the population dynamics of a small mammal at a large geographical scale and reveals a rather complex demographical history, which could have had bottom-up effects in the Late Pleistocene steppe-tundra ecosystem.
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| 6. |
- Pavlova, Elena V., et al.
(författare)
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Inhibition of UDP-glucosylceramide synthase in mice prevents Gaucher disease-associated B-cell malignancy
- 2015
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Ingår i: Journal of Pathology. - : Wiley. - 0022-3417. ; 235:1, s. 113-124
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Tidskriftsartikel (refereegranskat)abstract
- Clonal B-cell proliferation is a frequent manifestation of Gaucher disease-a sphingolipidosis associated with a high risk of multiple myeloma and non-Hodgkin lymphoma. Gaucher disease is caused by genetic deficiency of acid -glucosidase, the natural substrates of which (-d-glucosylceramide and -d-glucosylsphingosine) accumulate, principally in macrophages. Mice with inducible deficiency of -glucosidase [Gba(tm1Karl/tm1Karl)Tg(MX1-cre)1Cgn/0] serve as an authentic model of human Gaucher disease; we have recently reported clonal B-cell proliferation accompanied by monoclonal serum paraproteins and cognate tumours in these animals. To explore the relationship between B-cell malignancy and the biochemical defect, we treated Gaucher mice with eliglustat tartrate (GENZ 112638), a potent and selective inhibitor of the first committed step in glycosphingolipid biosynthesis. Twenty-two Gaucher mice received 300mg/kg of GENZ 112638 daily for 3-10 months from 6 weeks of age. Plasma concentrations of -d-glucosylceramide and the unacylated glycosphingolipid, -d-glucosylsphingosine, declined. After administration of GENZ 112638 to Gaucher mice for 3-10 months, serum paraproteins were not detected and there was a striking reduction in the malignant lymphoproliferation: neither lymphomas nor plasmacytomas were found in animals that had received the investigational agent. In contrast, 14 out of 60 Gaucher mice without GENZ 112638 treatment developed these tumours; monoclonal paraproteins were detected in plasma from 18 of the 44 age-matched mice with Gaucher disease that had not received GENZ 112638. Long-term inhibition of glycosphingolipid biosynthesis suppresses the development of spontaneous B-cell lymphoma and myeloma in Gaucher mice. Copyright (c) 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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| 7. |
- Pavlova, Elena
(författare)
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Vestibular control of body orientation in lamprey
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Maintenance of body orientation (postural control) is a vital motor function of the brain. The general goal of this project was to understand the organization and operation of neuronal networks responsible for postural control. The lamprey (a lower vertebrate) was used as a model animal. The postural control system in the lamprey, driven by vestibular input, maintains a definite orientation of the longitudinal body axis in relation to horizon (pitch angle) and the dorsal-side-up body orientation (roll angle is 0°). Important elements of the postural network are reticulospinal (RS) neurons, which are driven by vestibular input and transmit commands for postural corrections from the brain to the spinal cord. In in vivo studies, the activity of RS neurons was recorded from their axons in the spinal cord by chronically implanted electrodes. The animals were rotated through 3600 in the roll or pitch plane in order to stimulate vestibular organs. The activity of individual neurons was separated from the mass activity by a spike-sorting program. Rotation in the pitch plane revealed two groups of neurons (UP and DOWN), responding to nose-up and nose-down rotation, respectively. These groups presumably mediate opposing vestibular reflexes and cause downward and upward turns of the animal. 22% of the RS neurons responding to pitch tilts also responded to roll tilts. This overlap suggests that the RS pathways are partly shared by the pitch and roll control systems. A unilateral labyrinthectomy (UL) caused continuous rolling of the lamprey. Testing in the roll plane has shown that UL slightly affected responses on the UL side, whereas those on the opposite side disappeared. This asymmetry is the likely cause for the loss of equilibrium. Eye illumination led to a restoration of responses on the side contraleteral to UL, and to a reduction of responses on the opposite side. The restoration of symmetry of RS responses allows one to explain the behavioral effect of eye illumination . restoration of equilibrium. When animals were tested in the pitch plane before and after UL, in the group UP responses on the UL side changed only slightly, and on the opposite side they disappeared. In the group DOWN, the UL caused only minor changes in vestibular responses. Thus left and right UP subgroups receive their main input from the contralateral labyrinth. By contrast, neurons of group DOWN receive input from both labyrinths. The UL-induced changes in vestibular responses to pitch tilt will disturb the normal activity of the pitch control system. Normally, a few weeks after UL lampreys restore postural equilibrium (.vestibular compensation.). When behaviorally compensated animals were tested in the roll plane, it was found that vestibular responses on the side contralateral to UL reappeared, partly restoring symmetry in RS responses. These findings support the hypothesis that the recovery of postural control after UL is due to a restoration of symmetry in the RS motor commands. In vitro experiments were performed on the brainstem-spinal cord preparation, with intracellular stimulation of individual RS and vestibulospinal (VS) neurons, and recording the responses to these stimuli from spinal motoneurons. Most of the neurons produced effects on motor output, enhancing or suppressing it. The effects of VS neurons on different groups of motoneurons were weaker and less diverse than those of RS neurons. The RS and VS patterns of responses and the extent of neuronal projections suggest that VS neurons are responsible for flexion of the rostral part of the body and turns of the head in different planes, whereas RS neurons are responsible for formation of gross motor synergies.
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| 8. |
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| 9. |
- Sinding, Mikkel-Holger S., et al.
(författare)
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Arctic-adapted dogs emerged at the Pleistocene-Holocene transition
- 2020
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 368:6498
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Tidskriftsartikel (refereegranskat)abstract
- Although sled dogs are one of the most specialized groups of dogs, their origin and evolution has received much less attention than many other dog groups. We applied a genomic approach to investigate their spatiotemporal emergence by sequencing the genomes of 10 modern Greenland sled dogs, an similar to 9500-year-old Siberian dog associated with archaeological evidence for sled technology, and an similar to 33,000-year-old Siberian wolf. We found noteworthy genetic similarity between the ancient dog and modern sled dogs. We detected gene flow from Pleistocene Siberian wolves, but not modern American wolves, to present-day sled dogs. The results indicate that the major ancestry of modern sled dogs traces back to Siberia, where sled dog-specific haplotypes of genes that potentially relate to Arctic adaptation were established by 9500 years ago.
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| 10. |
- Tonkov, Spassimir, et al.
(författare)
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On the Holocene vegetation history of the Central Rila Mountains, Bulgaria : The palaeoecological record of peat bog Vodniza (2113 m)
- 2018
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Ingår i: Review of Palaeobotany and Palynology. - : ELSEVIER SCIENCE BV. - 0034-6667 .- 1879-0615. ; 250, s. 16-26
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Tidskriftsartikel (refereegranskat)abstract
- Information on the Holocene vegetation history of the Central Rila Mountains for the last 10,000 years was obtained by means of pollen and fossil stomata analyses of a 500 cm core retrieved from peat bog Vodniza (2113 ma.s.l.), and supported by radiocarbon chronology. The early Holocene afforestation started with an initial Betula phase with stands of Juniperus and Pinus which occupied barren soils (10,000-8300 cal. yrs. BP) while deciduous oak forests with abundant Tilia, Ulmus, Acer, and later on Corylus, spread at lower elevations. During the Holocene climatic optimum (8300-6000 cal. yrs. BP) the conifers Pious (Pious sylvestris, Pinus mugo, Pinus peuce) and Abies expanded at the expense of the birch and oak forests. The tree line was running above 2100 m comparable to the present-day situation and started to descend after ca. 3200 cal. yrs. BP mostly due to human impact. The last tree which penetrated into the coniferous belt after 3400 cal. yrs. BP and reached altitudes of 2000-2100 m, confirmed by the find of fossil stomata, was Picea abies. Its maximal distribution was achieved between 2250 and 1100 cal. yrs. BP, alongside with some enlargement of beech communities. The first indications of stockbreeding and other human activities in the Central Rila Mountains were recorded since 3400-3200 cal. yrs. BP (Late Bronze Age). The vegetation reconstruction during the Holocene followed a pattern coherent with the information from the Northern Pirin and partly from the Western Rhodopes Mountains. The palaeoecological evidence from the Rila Mountains could be compared in broad lines with the high quality data obtained from the Romanian Carpathians by the application of multi-proxy research approach.
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