| 1. |
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| 2. |
- Gunnarsson, S., et al.
(författare)
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Effects of short-day treatment on long-term growth performance and maturation of farmed Arctic charr Salvelinus alpinus reared in brackish water
- 2014
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112. ; 85:4, s. 1211-1226
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Tidskriftsartikel (refereegranskat)abstract
- The effects of a 6 week short-day photoperiod followed by continuous light, applied during the juvenile phase of Arctic charr Salvelinus alpinus in fresh water on smoltification and on the long-term growth andmaturity following transfer to brackish water (BW) (constant salinity of either 17 and 27 or increasing salinity in steps from 17 to 27) were investigated. Prior to salinity transfer, the juveniles were either reared at continuous light (C group) or reared for 6 weeks on a short day (8L: 16D, S group) followed by continuous light (24L: 0D). Increased salinity had negative effect on growth, with female fish reared at 17 salinity weighing 19 and 27% more than the salinity-step group (17-27) and the 27 salinity group, respectively. The stepwise acclimation to salinity had limited advantage in terms of growth rate. Short photoperiod for 6 weeks (November to January) followed by continuous light improved growth, but not seawater (SW) tolerance. Gill Na+, K+-ATPase activity and plasma Na+ levels changed with time, indicating some variation in osmoregulatory capacity during the experimental period. Overall, there appear to be interactive effects on maturation from applying short-day photoperiod followed by rearing at higher salinities. Plasma leptin varied with time and may be linked to stress caused by the observed variations in osmoregulatory ability. It is concluded that changes in growth rates observed in this study are mainly related to rearing salinity with higher growth rates at lower salinities. Short-day photoperiod has some growth-inducing effects but did not improve SW tolerance. Farmers of S. alpinus using BW for land-based rearing should keep salinity at moderate and stable levels according to these results to obtain best growth.
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| 3. |
- Moum, T, et al.
(författare)
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Mitochondrial DNA sequence evolution and phylogeny of the Atlantic Alcidae, including the extinct great auk (Pinguinus impennis)
- 2002
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Ingår i: Molecular biology and evolution. - 0737-4038. ; 19:9, s. 1434-1439
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Tidskriftsartikel (refereegranskat)abstract
- The Atlantic auk assemblage includes four extant species, razorbill (Alca torda), dovekie (Alle alle), common murre (Uria aalge), and thick-billed murre (U. lomvia), and one recently extinct species, the flightless great auk (Pinguinus impennis). To determine the phylogenetic relationships among the species, a contiguous 4.2-kb region of the mitochondrial genome from the extant species was amplified using PCR. This region included one ribosomal RNA gene, four transfer RNA genes, two protein-coding genes, the control region, and intergenic spacers. Sets of PCR primers for amplifying the same region from great auk were designed from sequences of the extant species. The authenticity of the great auk sequence was ascertained by alternative amplifications, cloning, and separate analyses in an independent laboratory. Phylogenetic analyses of the entire assemblage, made possible by the great auk sequence, fully resolved the phylogenetic relationships and split it into two primary lineages, Uria versus Alle, Alca, and Pinguinus. A sister group relationship was identified between Alca and Pinguinus to the exclusion of Alle. Phylogenetically, the flightless great auk originated late relative to other divergences within the assemblage. This suggests that three highly divergent species in terms of adaptive specializations, Alca, Alle, and Pinguinus, evolved from a single lineage in the Atlantic Ocean, in a process similar to the initial adaptive radiation of alcids in the Pacific Ocean.
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| 4. |
- Arnason, T., et al.
(författare)
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Effects of salinity and temperature on growth, plasma ions, cortisol and immune parameters of juvenile Atlantic cod (Gadus morhua)
- 2013
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486. ; 380-383, s. 70-79
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Tidskriftsartikel (refereegranskat)abstract
- The effects of salinity and temperature on growth, plasma ions, cortisol and immune parameters were investigated in two experiments. In the first experiment small, medium and large juvenile Atlantic cod Gadus morhua (initial average weights of 1.9, 8 and 83 g, respectively) were reared at four constant salinities (6 to 32 parts per thousand) for a short period (19-57 days, depending on size), then returned to seawater (32 parts per thousand) without acclimation and reared for another period (20-391 days). The highest growth rates were found at 10 parts per thousand in all size-classes. After the fish were returned to seawater the growth rates were inversely related to the salinity change in all size-classes and long-term rearing of the medium-sized fish revealed that abrupt salinity increase from 6 and 10 parts per thousand to seawater may permanently reduce the growth capacity of juvenile cod. In another long-term experiment, there was no significant difference in the growth rate of cod (initial average weight 3.4 g) reared at either 13.5 or 32 parts per thousand for 187 days. Rearing at 13.5 parts per thousand neither enhanced growth rate at 6.3 degrees C nor at 10 degrees C in larger juveniles (>245 g) compared with rearing in seawater. The study shows that rearing salinity and abrupt salinity changes have limited or no effects on stress and immune-related parameters, and there are no indications of ion regulatory disturbances at salinities as low as 6 parts per thousand. This shows that the Atlantic cod is an extremely euryhaline marine teleost species, and indicates that commercial Atlantic cod aquaculture can just as well be carried out in locations with low as with high environmental salinity. (C) 2012 Published by Elsevier B.V.
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| 5. |
- Arnason, T., et al.
(författare)
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Impact of temperature and growth hormone on growth physiology of juvenile Atlantic wolffish (Anarhichas lupus)
- 2019
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486. ; 504, s. 404-413
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Tidskriftsartikel (refereegranskat)abstract
- The effects of temperature and growth hormone (GH) implantation on growth of juvenile Atlantic wolffish (Anarhichas lupus) were investigated. The year-long study had three sequential experimental phases (EP) termed EP1, EP2 and EP3, lasting for 6, 9 and 37 weeks, respectively. The experimental fish were divided into four groups and reared at different target temperatures (3, 7, 11 and 15 degrees C) during EP1 and EP2, but at a constant temperature of 7 degrees C during EP3. At the beginning of EP2, half of the fish from each group was implanted with formulation of recombinant bovine GH (Posilac (R)), while the other half was sham-implanted with vehicle. The optimal temperature for growth (T-opt.G) of early juveniles (geometric mean weight 7.5 g) was determined as 12.1 degrees C during EP1, while the upper critical temperature (Tc) was concluded to be very close to 15 degrees C, as fish at that temperature had stunted growth, increased mortality and showed external signs of skeletal deformities. Thus, the species was found to be relatively stenothermic during the early juvenile stages and therefore vulnerable to relatively modest increases in environmental temperature above T-opt.G At 15 degrees C, GH implantation had no effects on growth rate. This indicates that the high allostatic load at this temperature leaves no scope for increased growth. In contrast, at lower rearing temperatures, the GH implantation had substantial, long-term effects on growth rate and induced remarkably similar relative growth stimulation at 3, 7 and 11 degrees C, suggesting a temperature-independent mechanism for the growth-promoting effects of GH.
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| 6. |
- Arnason, T., et al.
(författare)
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Long-term rearing of Arctic charr Salvelinus alpinus under different salinity regimes at constant temperature
- 2014
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112. ; 85:4, s. 1145-1162
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Tidskriftsartikel (refereegranskat)abstract
- Arctic charr Salvelinus alpinus of the Holar strain (mean+/- s. e. body mass= 152.1+/-3.1g) were reared at four different salinity regimes at a constant temperature of 7.4 degrees C. Two groups were given a three-month acclimation in salinity 18 before the salinity was increased to either 25 or 29 (groups called A25 and A29), and two groups were reared in salinities 25 or 29 over the full experimental period of 409 days (groups called F25 and F29). In the first 3months, the A25 and A29 groups had the highest growth rates. By October 2011, there were no significant differences (two-way nested ANOVA, P> 0.05) in the mean body masses among A25, F25 and F29 (c. 1450 g), whereas A29 had a lower mean mass (1282 g). The growth in the last period from October 2011 to January 2012 was reduced by sexual maturation in the highest salinity regimes (A29 and F29), whereas fish in groups A25 and F25 showed high growth throughout the study. Males in all salinity groups had higher growth rates than females for the most part of the study, but the divergence between the sexes was most pronounced in the highest salinity regimes. All salinity groups showed distinct changes in Na+, K+-ATPase activity, with high activity in spring and summer, and lower activity in the autumn. Plasma sodium (Na+) levels were stable indicating that none of the experimental groups had problems in maintaining hydromineral balance during the study. While plasma leptin levels were not affected by salinity regimes, it was noted that these levels were 13-30% higher in fish with empty guts compared with those having food in their gut at the time of sampling. This suggests a link between leptin levels and food intake, indicating that this hormone may play a role in food intake and energy allocation in fishes.
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| 7. |
- Elmerot, Christian, et al.
(författare)
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The mitochondrial genome of the pufferfish, Fugu rubripes, and ordinal teleostean relationships
- 2002
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Ingår i: Gene. - 1879-0038. ; 295:2, s. 163-172
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Tidskriftsartikel (refereegranskat)abstract
- The small nuclear genome of the pufferfish, Fugu rubripes (order Tetraodontiformes), makes this species highly interesting for genome research. In order to establish the phylogenetic position of the Tetraodontiformes relative to other teleostean orders that might also have a reduced nuclear genome size, we have sequenced the mitochondrial (mt) genome of the pufferfish. The gene order, nucleotide composition and evolutionary rate of the mt genome of the fugu correspond to those of other teleosts. This suggests that the evolution of this genome has not been affected by the processes that led to the dramatic reduction of the size of the nuclear genome of the fugu. The phylogenetic analyses, which were based on the concatenated amino acid sequences of twelve protein-coding rut genes, placed the fugu among the percomorphs. The affinities between the Tetraodontiformes and either the Perciformes or the Zeiformes were limited, however. The common notion of a separate euteleostean clade remained unsupported. The analyses did not support the traditional systematic understanding that the Clupei-formes constitute a basal teleostean lineage. In addition the findings strongly suggest that three teleostean orders, the Perciformes, Zeiformes and Scorpaeniformes, are paraphyletic. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 8. |
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| 9. |
- Jäderkvist Fegraeus, Kim, et al.
(författare)
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The DMRT3 'Gait keeper' mutation affects performance of Nordic and Standardbred trotters
- 2014
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Ingår i: Journal of Animal Science. - : Oxford University Press (OUP). - 0021-8812 .- 1525-3163. ; 92:10, s. 4279-4286
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Tidskriftsartikel (refereegranskat)abstract
- In a previous study it was shown that a nonsense mutation in the DMRT3 gene alters the pattern of locomotion in horses and that this mutation has a strong positive impact on trotting performance of Standardbreds. One aim of this study was to test if racing performance and trotting technique in the Nordic (Coldblood) trotters are also influenced by the DMRT3 genotype. Another aim was to further investigate the effect of the mutation on performance in Standardbreds, by using a within-family analysis and genotype-phenotype correlations in a larger horse material than in the previous study. We genotyped 427 Nordic trotters and 621 Standardbreds for the DMRT3 nonsense mutation and a SNP in strong linkage disequilibrium with it. In Nordic trotters, we show that horses homozygous for the DMRT3 mutation (A) had significantly higher EBV for trotting performance traits than heterozygous (CA) or homozygous wild-type (CC) horses (P = 0.001). Furthermore, AA homozygotes had a higher proportion of victories and top 3 placings than horses heterozygous or homozygous wild-type, when analyzing performance data for the period 3 to 6 yr of age (P = 0.06 and P = 0.05, respectively). Another finding in the Nordic trotters was that the DMRT3 mutation influenced trotting technique (P = 2.1 x 10(-8)). Standardbred horses homozygous AA had significantly higher EBV for all traits than horses with at least 1 wild-type allele (CA and CC; P = 1.6 x 10(-16)). In a within-family analysis of Standardbreds, we found significant differences in several traits (e. g., earnings, P = 0.002; number of entered races, P = 0.004; and fraction of offspring that entered races, P = 0.002) among paternal half-sibs with genotype AA or CA sired by a CA stallion. For most traits, we found significant differences at young ages. For Nordic trotters, most of the results were significant at 3 yr of age but not for the older ages, and for the Standardbreds most of the results for the ages 3 to 5 were significant. For Nordic trotters, the proportion of victories and placings were the only traits that were significant for other ages than 3 yr.
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| 10. |
- Jäderkvist Fegraeus, Kim, et al.
(författare)
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To pace or not to pace : a pilot study of four- and five-gaited Icelandic horses homozygous for the DMRT3 'Gait Keeper' mutation
- 2017
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Ingår i: Animal Genetics. - : Wiley. - 0268-9146 .- 1365-2052. ; 48:6, s. 694-697
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Tidskriftsartikel (refereegranskat)abstract
- The Icelandic horse is a breed known mainly for its ability to perform the ambling four-beat gait 'tolt' and the lateral two-beat gait pace. The natural ability of the breed to perform these alternative gaits is highly desired by breeders. Therefore, the discovery that a nonsense mutation (C>A) in the DMRT3 gene was the main genetic factor for horses' ability to perform gaits in addition to walk, trot and canter was of great interest. Although several studies have demonstrated that homozygosity for the DMRT3 mutation is important for the ability to pace, only about 70% of the homozygous mutant (AA) Icelandic horses are reported to pace. The aim of the study was to genetically compare four-and five-gaited (i.e. horses with and without the ability to pace) AA Icelandic horses by performing a genome-wide association (GWA) analysis. All horses (n = 55) were genotyped on the 670K Axiom Equine Genotyping Array, and a GWA analysis was performed using the GENABEL package in R. No SNP demonstrated genome-wide significance, implying that the ability to pace goes beyond the presence of a single gene variant. Despite its limitations, the current study provides additional information regarding the genetic complexity of pacing ability in horses. However, to fully understand the genetic differences between four-and five-gaited AA horses, additional studies with larger sample materials and consistent phenotyping are needed.
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| 11. |
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| 12. |
- Kutschera, Verena E., et al.
(författare)
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High genetic variability of vagrant polar bears illustrates importance of population connectivity in fragmented sea ice habitats
- 2016
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Ingår i: Animal Conservation. - : Wiley. - 1367-9430 .- 1469-1795. ; 19:4, s. 337-349
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Tidskriftsartikel (refereegranskat)abstract
- Projections by the Intergovernmental Panel on Climate Change (IPCC) and sea ice forecasts suggest that Arctic sea ice will decline markedly in coming decades. Expected effects on the entire ecosystem include a contraction of suitable polar bear habitat into one or few refugia. Such large-scale habitat decline and fragmentation could lead to reduced genetic diversity. Here we compare genetic variability of four vagrant polar bears that reached Iceland with that in recognized subpopulations from across the range, examining 23 autosomal microsatellites, mitochondrial control region sequences and Y-chromosomal markers. The vagrants' genotypes grouped with different genetic clusters and showed similar genetic variability at autosomal microsatellites (expected heterozygosity, allelic richness, and individual heterozygosity) as individuals in recognized subpopulations. Each vagrant carried a different mitochondrial haplotype. A likely route for polar bears to reach Iceland is via Fram Strait, a major gateway for the physical exportation of sea ice from the Arctic basin. Vagrant polar bears on Iceland likely originated from more than one recognized subpopulation, and may have been caught in sea ice export during long-distance movements to the East Greenland area. Although their potentially diverse geographic origins might suggest that these vagrants encompass much higher genetic variability than vagrants or dispersers in other regions, the four Icelandic vagrants encompassed similar genetic variability as any four randomly picked individuals from a single subpopulation or from the entire sample. We suggest that this is a consequence of the low overall genetic variability and weak range-wide genetic structuring of polar bears - few dispersers can represent a large portion of the species' gene pool. As predicted by theory and our demographic simulations, continued gene flow will be necessary to counteract loss of genetic variability in increasingly fragmented Arctic habitats. Similar considerations will be important in the management of other taxa that utilize sea ice habitats.
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| 13. |
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| 14. |
- Palsdottir, A, et al.
(författare)
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Study of restriction fragment length polymorphism in the cystatin C gene of elderly patients with dementia and aged Down's syndrome patients
- 1989
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Ingår i: Progress in Clinical and Biological Research. - 0361-7742. ; 317, s. 235-239
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Tidskriftsartikel (refereegranskat)abstract
- Using a full length cystatin C cDNA probe and the Alu I restriction enzyme a total of 33 patients with senile dementia, Alzheimer type and 31 Down's syndrome patients have been investigated for the presence of the 630 bp Alu I restriction fragment length polymorphism in the cystatin C gene detected in Icelandic patients with hereditary cystatin C amyloid angiopathy. Results showed that all the patients had normal cystatin C fragment length of 600 bp.
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| 15. |
- Slack, Kerryn, et al.
(författare)
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Early penguin fossils, plus mitochondrial genomes, calibrate avian evolution
- 2006
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Ingår i: Molecular biology and evolution. - : Oxford University Press (OUP). - 0737-4038 .- 1537-1719. ; 23:6, s. 1144-1155
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Tidskriftsartikel (refereegranskat)abstract
- Testing models of macroevolution, and especially the sufficiency of microevolutionary processes, requires good collaboration between molecular biologists and paleontologists. We report such a test for events around the Late Cretaceous by describing the earliest penguin fossils, analyzing complete mitochondrial genomes from an albatross, a petrel, and a loon, and describe the gradual decline of pterosaurs at the same time modern birds radiate. The penguin fossils comprise four naturally associated skeletons from the New Zealand Waipara Greensand, a Paleocene (early Tertiary) formation just above a well-known Cretaceous/Tertiary boundary site. The fossils, in a new genus (Waimanu), provide a lower estimate of 61-62 Ma for the divergence between penguins and other birds and thus establish a reliable calibration point for avian evolution. Combining fossil calibration points, DNA sequences, maximum likelihood, and Bayesian analysis, the penguin calibrations imply a radiation of modern (crown group) birds in the Late Cretaceous. This includes a conservative estimate that modern sea and shorebird lineages diverged at least by the Late Cretaceous about 74 +/- 3 Ma (Campanian). It is clear that modern birds from at least the latest Cretaceous lived at the same time as archaic birds including Hesperornis, Ichthyornis, and the diverse Enantiornithiformes. Pterosaurs, which also coexisted with early crown birds, show notable changes through the Late Cretaceous. There was a decrease in taxonomic diversity, and small- to medium-sized species disappeared well before the end of the Cretaceous. A simple reading of the fossil record might suggest competitive interactions with birds, but much more needs to be understood about pterosaur life histories. Additional fossils and molecular data are still required to help understand the role of biotic interactions in the evolution of Late Cretaceous birds and thus to test that the mechanisms of microevolution are sufficient to explain macroevolution.
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| 16. |
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| 17. |
- Tetarenko, B. E., et al.
(författare)
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The First Low-Mass Black Hole X-Ray Binary Identified in Quiscence Outside of a Globular Cluster
- 2016
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Ingår i: Astrophysical Journal. - 1538-4357 .- 0004-637X. ; 825:1
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Tidskriftsartikel (refereegranskat)abstract
- The observed relation between the X-ray and radio properties of low-luminosity accreting black holes (BHs) has enabled the identification of multiple candidate black hole X-ray binaries (BHXBs) in globular clusters (GCs). Here, we report an identification of the radio source VLA J213002.08+120904 (aka M15 S2), recently reported in Kirsten et al., as a BHXB candidate. They showed that the parallax of this flat-spectrum variable radio source indicates a - + 2.2 0.30.5 kpc distance, which identifies it as lying in the foreground of the GC M15. We determine the radio characteristics of this source and place a deep limit on the X-ray luminosity of ∼4 × 1029 erg s.1. Furthermore, we astrometrically identify a faint red stellar counterpart in archival Hubble images with colors consistent with a foreground star; at 2.2 kpc, its inferred mass is 0.1-0.2Me. We rule out that this object is a pulsar, neutron star X-ray binary, cataclysmic variable, or planetary nebula, concluding that VLA J213002.08+120904 is the first accreting BHXB candidate discovered in quiescence outside of a GC. Given the relatively small area over which parallax studies of radio sources have been performed, this discovery suggests a much larger population of quiescent BHXBs in our Galaxy, 2.6 ± 104-1.7 × 108 BHXBs at 3× confidence, than has been previously estimated (∼102-104) through population synthesis.The observed relation between the X-ray and radio properties of low-luminosity accreting black holes (BHs) has enabled the identification of multiple candidate black hole X-ray binaries (BHXBs) in globular clusters (GCs). Here, we report an identification of the radio source VLA J213002.08+120904 (aka M15 S2), recently reported in Kirsten et al., as a BHXB candidate. They showed that the parallax of this flat-spectrum variable radio source indicates a - + 2.2 0.30.5 kpc distance, which identifies it as lying in the foreground of the GC M15. We determine the radio characteristics of this source and place a deep limit on the X-ray luminosity of ∼4 × 1029 erg s.1. Furthermore, we astrometrically identify a faint red stellar counterpart in archival Hubble images with colors consistent with a foreground star; at 2.2 kpc, its inferred mass is 0.1-0.2Me. We rule out that this object is a pulsar, neutron star X-ray binary, cataclysmic variable, or planetary nebula, concluding that VLA J213002.08+120904 is the first accreting BHXB candidate discovered in quiescence outside of a GC. Given the relatively small area over which parallax studies of radio sources have been performed, this discovery suggests a much larger population of quiescent BHXBs in our Galaxy, 2.6 ± 104-1.7 × 108 BHXBs at 3× confidence, than has been previously estimated (∼102-104) through population synthesis.
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| 18. |
- Wettergren, Yvonne, 1957, et al.
(författare)
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C-band-positive double minutes have kinetochore proteins.
- 1995
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Ingår i: Cytogenetics and cell genetics. - : S. Karger AG. - 0301-0171. ; 68:1-2, s. 54-6
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Tidskriftsartikel (refereegranskat)abstract
- Double minutes (DMs) have been shown generally to lack centromeres. In the present paper we report on C-band-positive DMs in Colcemid-resistant SEWA cells. These DMs were heavily labeled after in situ hybridization with mouse major satellite DNA and, furthermore, reacted positively with antikinetochore antibodies. Upon antikinetochore antibody labeling, the immunofluorescent signals of some DMs were strong, indicating that they had functional centromeres.
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