| 1. |
|
|
| 2. |
- Ruzzante, D. E., et al.
(författare)
-
Biocomplexity in a highly migratory pelagic marine fish, Atlantic herring
- 2006
-
Ingår i: Proceedings of the Royal Society B-Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 273:1593, s. 1459-1464
-
Tidskriftsartikel (refereegranskat)abstract
- The existence of biologically differentiated populations has been credited with a major role in conferring sustainability and in buffering overall productivity of anadromous fish population complexes where evidence for spatial structure is uncontroversial. Here, we describe evidence of correlated genetic and life history (spawning season linked to spawning location) differentiation in an abundant and highly migratory pelagic fish, Atlantic herring, Clupea harengus, in the North Sea (NS) and adjacent areas. The existence of genetically and phenotypically diverse stocks in this region despite intense seasonal mixing strongly implicates natal homing in this species. Based on information from genetic markers and otolith morphology, we estimate the proportional contribution by NS, Skagerrak (SKG) and Kattegat and western Baltic (WBS) fish to mixed aggregations targeted by the NS fishery. We use these estimates to identify spatial and temporal differences in life history (migratory behaviour) and habitat use among genetically differentiated migratory populations that mix seasonally. Our study suggests the existence of more complex patterns of intraspecific diversity than was previously recognized. Sustainability may be compromised if such complex patterns are reduced through generalized management (e.g. area closures) that overlooks population differences in spatial use throughout the life cycle.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Hammarstedt, Lilian, et al.
(författare)
-
Human papillomavirus as a risk factor for the increase in incidence of tonsillar cancer
- 2006
-
Ingår i: Int J Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 119:11, s. 2620-3
-
Tidskriftsartikel (refereegranskat)abstract
- Smoking and alcohol are well-known etiological factors in tonsillar cancer. However, as in cervical cancer, human papillomavirus (HPV) is currently found in a sizable proportion of tonsillar cancer. Recent reports from the U.S. and Finland show an increase in the incidence of tonsillar cancer, without a parallel rise in smoking and alcohol consumption. This study investigates whether the incidence of tonsillar cancer has also changed in Sweden and whether a possible explanation of the increase is a higher proportion of HPV-positive tonsillar cancer. The incidence of tonsillar cancer between 1970 and 2002 in the Stockholm area was obtained from the Swedish Cancer Registry. In parallel, 203 pretreatment paraffin-embedded tonsillar cancer biopsies taken during 1970-2002 from patients in the Stockholm area were tested for presence of HPV DNA by PCR. The incidence of tonsillar cancer increased 2.8-fold (2.6 in men and 3.5 in women) from 1970 to 2002. During the same period, a significant increase in the proportion of HPV-positive tonsillar cancer cases was observed, as it increased 2.9-fold (p < 0.001). The distribution of HPV-positive cases was 7/30 (23.3%) in the 1970s, 12/42 (29%) in the 1980s, 48/84 (57%) in the 1990s and 32/47 (68%) during 2000-2002. We have demonstrated a highly significant and parallel increase both in the incidence of tonsillar cancer and the proportion of HPV-positive tumors. Hence, HPV may play an important role for the increased incidence of tonsillar cancer. This should definitely influence future preventive strategies as well as treatment for this type of cancer.
|
|
| 7. |
- Mariani, S., et al.
(författare)
-
North Sea herring population structure revealed by microsatellite analysis
- 2005
-
Ingår i: Marine Ecology-Progress Series. - 0171-8630. ; 303, s. 245-257
-
Tidskriftsartikel (refereegranskat)abstract
- The Atlantic herring Clupea harengus has played a pivotal role in the formulation of ideas relating to population structuring in marine fishes, yet considerable uncertainty remains as to the extent to which phenotypic and genetic differentiation coincide in such a highly mobile species. In this study, we examined genetic population structure across the major herring spawning aggregations in the North Sea and adjacent waters over 2 years, 2002 and 2003. We analysed 1660 spawning individuals across 9 microsatellite loci. Data were analysed using several approaches, taking into account the effect of location, year-class and sex, as well as pooling all individuals together, making no assumption as to the number of populations present in the data set. The results suggest the presence of a genetically homogeneous unit off Northern Scotland, and a temporally stable pattern of isolation by distance determined predominantly by the divergence of the English Channel samples and, in 2003, by the Norwegian spring spawners. Our data suggest that the current view of North Sea herring as a unit-stock might be adequate, but confirm the considerable degree of demographic independence of the herring populations in the English Channel. Despite major recent population collapses, genetic data indicated no evidence of bottlenecks affecting the genetic diversity of extant North Sea herring populations. Finally, despite evidence of weak population structuring, we discuss the risks of underestimating population differentiation in marine fish of large population sizes, and with reference to herring population history and dynamics, we attempt to reconcile the existing theories on herring population structure.
|
|
| 8. |
- Stet, R. J. M., et al.
(författare)
-
Characterization of a major histocompatibility class II A gene (Clha-DAA) with an embedded microsatellite marker in Atlantic herring (Clupea harengus L.)
- 2008
-
Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 73:2, s. 367-381
-
Tidskriftsartikel (refereegranskat)abstract
- An Atlantic herring major histocompatibility class II A (Clha-DAA) cDNA sequence has been characterized and was shown to encode a leader peptide, alpha-1 domain, alpha-2 domain, connecting peptide, transmembrane and cytoplasmic region. The Clha-DAA protein sequence has all the characteristics of a teleost class II A protein with conserved cysteines in both the alpha-1 and the alpha-2 domains and two potential N-linked glycosylation sites. Exon 2 sequences encoding the polymorphic alpha-1 domain from different individuals were analysed and revealed the presence of at least two loci. The Clha-DAA gene consists of four exons and three short introns. Four unique intron 3 sequences from multiple individuals were obtained and were shown to contain a (TG)(n) microsatellite sequence. Primers were optimized such that only a single microsatellite locus designated Clha-DAA-INTR3 was amplified. Four herring populations from the North Sea and the Baltic Sea were genotyped for Clha-DAA-INTR3. In total, 16 Clha-DAA-INTR3 alleles were detected; the distribution of the alleles showed no deviation from Hardy-Weinberg expectation. Levels of genetic differentiation among samples were of similar magnitude as have been reported earlier for neutral microsatellite loci between northern North Sea and Baltic Sea herring populations. (C) 2008 The Authors Journal compilation (C) 2008 The Fisheries Society of the British Isles.
|
|
| 9. |
- Björkman, Lena, 1965, et al.
(författare)
-
Serum amyloid A mediates human neutrophil production of reactive oxygen species through a receptor independent of formyl peptide receptor like-1
- 2008
-
Ingår i: Journal of Leukocyte Biology. - : Oxford University Press (OUP). - 0741-5400 .- 1938-3673. ; 83:2, s. 245-53
-
Tidskriftsartikel (refereegranskat)abstract
- Serum amyloid A (SAA) is one of the acute-phase reactants, a group of plasma proteins that increases immensely in concentration during microbial infections and inflammatory conditions, and a close relationship between SAA levels and disease activity in rheumatoid arthritis (RA) has been observed. RA is an inflammatory disease, where neutrophils play important roles, and SAA is thought to participate in the inflammatory reaction by being a neutrophil chemoattractant and inducer of proinflammatory cytokines. The biological effects of SAA are reportedly mediated mainly through formyl peptide receptor like-1 (FPRL1), a G protein-coupled receptor (GPCR) belonging to the formyl peptide receptor family. Here, we confirmed the affinity of SAA for FPRL1 by showing that stably transfected HL-60 cells expressing FPRL1 were activated by SAA and that the response was inhibited by the use of the FPRL1-specific antagonist WRWWWW (WRW4). We also show that SAA activates the neutrophil NADPH-oxidase and that a reserve pool of receptors is present in storage organelles mobilized by priming agents such as TNF-alpha and LPS from Gram-negative bacteria. The induced activity was inhibited by pertussis toxin, indicating the involvement of a GPCR. However, based on FPRL1-specific desensitization and use of FPRL1 antagonist WRW4, we found the SAA-mediated effects in neutrophils to be independent of FPRL1. Based on these findings, we conclude that SAA signaling in neutrophils is mediated through a GPCR, distinct from FPRL1. Future identification and characterization of the SAA receptor could lead to development of novel, therapeutic targets for treatment of RA.
|
|
| 10. |
- Björstad, Åse, 1976, et al.
(författare)
-
The host defense peptide LL-37 selectively permeabilizes apoptotic leukocytes.
- 2009
-
Ingår i: Antimicrobial agents and chemotherapy. - 1098-6596. ; 53:3, s. 1027-38
-
Tidskriftsartikel (refereegranskat)abstract
- LL-37 is a cationic host defense peptide that is highly expressed during acute inflammation and that kills bacteria by poorly defined mechanisms, resulting in permeabilization of microbial membranes. High concentrations of LL-37 have also been reported to have cytotoxic effects against eukaryotic cells, but the peptide is clearly capable of differentiating between membranes with different compositions (eukaryotic versus bacterial membranes). Eukaryotic cells such as leukocytes change their membrane composition during apoptotic cell death, when they are turned into nonfunctional but structurally intact entities. We tested whether LL-37 exerted specific activity on apoptotic cells and found that the peptide selectively permeabilized the membranes of apoptotic human leukocytes, leaving viable cells unaffected. This activity was seemingly analogous to the direct microbicidal effect of LL-37, in that it was rapid, independent of known surface receptors and/or active cell signaling, and inhibitable by serum components such as high-density lipoprotein. A similar selective permeabilization of apoptotic cells was recorded for both NK cells and neutrophils. In the latter cell type, LL-37 permeabilized both the plasma and granule membranes, resulting in the release of both lactate dehydrogenase and myeloperoxidase. Apoptosis is a way for inflammatory cells to die silently and minimize collateral tissue damage by retaining tissue-damaging and proinflammatory substances within intact membranes. Permeabilization of apoptotic leukocytes by LL-37, accompanied by the leakage of cytoplasmic as well as intragranular molecules, may thus shift the balance between pro- and anti-inflammatory signals and in this way be of importance for the termination of acute inflammation.
|
|
| 11. |
|
|
| 12. |
- Dahlgren, Curt, et al.
(författare)
-
Ashes: Sweden
- 2005
-
Ingår i: Encyclopedia of Cremation. - 0754637735 ; , s. 60-64
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The article presents results from an investigation made in southern Sweden in 2001. Ten relatives of people whose remains were scattered were interviewed about the circumstances of the scattering. The forms for scattering the ashes varied depending on the locality. In several cases relatives scattered the ashes alone or together, and in some cases funeral directors and a minister did it. Reciting poems, singing hymns or traditional songs are not uncommon. Overall, the ceremony was a positive experience for the relatives, and it was seen as a terminal point of a long process. Several of the relatives also recognized the scattering of ashes as an option for the disposal of their own bodies after death. It is suggested that the scattering of ashes can be seen as a post-modern way of relating to rites of death.
|
|
| 13. |
- Dahlgren, Curt, et al.
(författare)
-
Changing Customs in the late 1990s
- 2005
-
Ingår i: Encyclopedia of Cremation. - 0754637735 ; , s. 60-64
-
Bokkapitel (populärvet., debatt m.m.)abstract
- In the late 1990s in Sweden a growing number of people chose to scatter the ashes of their cremated relatives in places other than public or private burial grounds. The option of scattering was, itself, made possible in 1957, and is strictly regulated. It is possible to see the private taking care of the ashes as a post-modern way of relating to rites of death. The purposes of these acts are to handle and structure a process, an event, an important value, or to create a meaning-shaping situation, which involves a considering of the will and intention of the deceased.
|
|
| 14. |
- Dahlgren, Hanna, et al.
(författare)
-
First direct optical observations of plasma flows using afterglow of O+ in discrete aurora
- 2009
-
Ingår i: Journal of Atmospheric and Solar-Terrestrial Physics. - : Elsevier BV. - 1364-6826 .- 1879-1824. ; 71:2, s. 228-238
-
Tidskriftsartikel (refereegranskat)abstract
- Imaging of active structured aurora in the forbidden O+ ion line at 732.0 nm provides a possibility of direct observation of plasma drifts in the topside ionosphere. The metastable O+ P-2 state has a radiative lifetime of 5 s, so the oxygen ions can be detected after the precipitation creating them has ceased. The decay time of the O+ emission is studied and modelled with a time-dependent electron transport and ion chemistry model. Four examples are given of O+ afterglow observed with the multi-spectral imager, auroral structure and kinetics (ASK), which was located near Tromso, Norway, in 2006. Estimates are given of drift velocities resulting from the analysis of the afterglow motions. Bulk plasma velocities of 340 and 720 m/s directed eastwards were found for two afterglowing arc filaments, corresponding to southward electric fields of 18 and 40 mV/m, respectively.
|
|
| 15. |
- Dahlgren, Hanna, 1980-, et al.
(författare)
-
Morphology and dynamics of aurora at fine scale : first results for the ASK instrument
- 2008
-
Ingår i: Annales Geophysicae. - : Copernicus GmbH. - 0992-7689 .- 1432-0576. ; 26:5, s. 1041-1048
-
Tidskriftsartikel (refereegranskat)abstract
- The ASK instrument (Auroral Structure and Kinetics) is a narrow field auroral imager, providing simultaneous images of aurora in three different spectral bands at multiple frames per second resolution. The three emission species studied are O-2(+) (5620 angstrom), O+ (7319 angstrom) and O (7774 angstrom). ASK was installed and operated for the first time in an observational campaign on Svalbard, from December 2005 to March 2006. The measurements were supported by data from the Spectrographic Imaging Facility (SIF). The relation between the morphology and dynamics of the visible aurora and its spectral characteristics is studied for selected events from this period. In these events it is found that dynamic aurora is coupled to high energy electron precipitation. By studying the O-2(+)/O intensity ratio we find that some auroral filaments are caused by higher energy precipitation within regions of lower energy precipitation, whereas other filaments are the result of a higher particle flux compared to the surroundings.
|
|
| 16. |
- Dahlgren, Hanna, 1980-, et al.
(författare)
-
Using spectral characteristics to interpret auroral imaging in the 731.9 nm 0+ line
- 2008
-
Ingår i: Annales Geophysicae. - : Copernicus GmbH. - 0992-7689 .- 1432-0576. ; 26:7, s. 1905-1917
-
Tidskriftsartikel (refereegranskat)abstract
- Simultaneous observations were made of dynamic aurora during substorm activity on 26 January 2006 with three high spatial and temporal resolution instruments: the ASK (Auroral Structure and Kinetics) instrument, SIF (Spectrographic Imaging Facility) and ESR (EISCAT Svalbard Radar), all located on Svalbard (78° N, 16.2° E). One of the narrow field of view ASK cameras is designed to detect O+ ion emission at 731.9 nm. From the spectrographic data we have been able to determine the amount of contaminating N2 and OH emission detected in the same filter. This is of great importance to further studies using the ASK instrument, when the O+ ion emission will be used to detect flows and afterglows in active aurora. The ratio of O+ to N2 emission is dependent on the energy spectra of electron precipitation, and was found to be related to changes in the morphology of the small-scale aurora. The ESR measured height profiles of electron densities, which allowed estimates to be made of the energy spectrum of the precipitation during the events studied with optical data from ASK and SIF. It was found that the higher energy precipitation corresponded to discrete and dynamic features, including curls, and low energy precipitation corresponded to auroral signatures that were dominated by rays. The evolution of these changes on time scales of seconds is of importance to theories of auroral acceleration mechanisms.
|
|
| 17. |
- Dahlgren, Thomas G., 1963, et al.
(författare)
-
First record of Antarctic whale-fall species.
- 2009
-
Ingår i: 4th International Symposium on Chemosynthesis-Based Ecosystems (4th CBE). Okinawa June 28 - July 3 2009..
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
|
|
| 18. |
- Fabel, D., et al.
(författare)
-
Retreat rate of the northern Fennoscandian Ice Sheet margin
- 2007
-
Ingår i: Geophysical Research Abstracts.
-
Konferensbidrag (refereegranskat)abstract
- The deglaciation chronologies of the northern and north-eastern margins of the Fennoscandian Ice Sheet are relatively poorly constrained. This is because the principal methodological tool to trace and date the deglaciation pattern, the occurrence of deglaciation varves, does not apply in the northernmost regions of Fennoscandia. Moreover, a paucity of radiocarbon dates allows for only a most generalised pattern for the post-Younger Dryas shrinkage of the ice sheet to its final deglaciation configuration in the northern Swedish mountains. We are tracing the deglaciation of the Fennoscandian Ice Sheet from its Younger Dryas terminal moraines in northern Norway and eastern Finland towards the northern Swedish mountains, using cosmogenic nuclide apparent exposure ages of depositional and erosional features related to the former ice sheet margin. Because the ice sheet had initially warm-based conditions close to its margin, the dominant morphology is one of eskers and aligned lineation systems such as crag-and-tails. Abundant meltwater has locally eroded bedrock to considerable depth and deposited fans or deltas perched above current local base levels. Subglacial conditions during final deglaciation close to the mountain range were cold-based, thus inhibiting the formation of eskers and lineation systems. However, there is a ubiquity of meltwater erosional imprints and occasional plucking scars where, locally, pressure-melting conditions were reached. Surface exposure ages from these different geomorphological settings should yield true deglaciation ages provided the following conditions are met, (i) erosion on crags of crag-and-tails, across transverse erosional scarps, and in meltwater channels has exposed bedrock surfaces without a prior exposure history, and (ii) depositional features contain exposed boulders without a prior exposure history. Results show that transverse erosional scarps and erratics yield reliable deglaciation ages, but that bedrock samples from meltwater channels and crag-and-tails and sediment samples from eskers occasionally yield unreliable deglaciation ages due to cosmogenic nuclide inheritance and potential shielding by snow. Apparent deglaciation ages range from _14 ka at the Younger Dryas moraine to _8 ka approximately 500 km to the south in the northern Swedish Mountains. The spread of ages do not deviate from what would be expected for a regular uninterrupted retreat by the ice margin
|
|
| 19. |
|
|
| 20. |
|
|
| 21. |
|
|
| 22. |
- Magnuson Osborn, Teresia, 1977, et al.
(författare)
-
Modifications of cellular responses to lysophosphatidic acid and platelet-activating factor by plasma gelsolin
- 2007
-
Ingår i: Am J Physiol Cell Physiol. - : American Physiological Society. - 0363-6143 .- 1522-1563. ; 292:4
-
Tidskriftsartikel (refereegranskat)abstract
- Gelsolin is a highly conserved intracellular actin-binding protein with an extracellular isoform, plasma gelsolin (pGSN). Blood concentrations of pGSN decrease in response to diverse tissue injuries. Depletion of pGSN to critical levels precedes and often predicts complications of injuries such as lung permeability changes and death. Administration of recombinant pGSN ameliorates such complications and reduces mortality in animal models. One proposed mechanism for pGSN's protective effects is that it inhibits inflammatory mediators generated during primary injuries, since pGSN binds bioactive mediators, including lysophospatidic acid (LPA) and endotoxin in vitro. However, no direct evidence in support of this hypothesis has been available. Here we show that recombinant pGSN modestly inhibited LPA-induced P-selectin upregulation by human platelets in the presence of albumin (P < 0.0001). However, physiologically relevant pGSN concentrations inhibit platelet-activating factor (PAF)-mediated P-selectin expression by up to 77% (P < 0.0001). pGSN also markedly inhibited PAF-induced superoxide anion (O(2)(-)) production of human peripheral neutrophils (PMN) in a concentration-dependent manner (P < 0.0001). A phospholipid-binding peptide derived from pGSN (QRLFQVKGRR) also inhibited PAF-mediated O(2)(-) generation (P = 0.024). Therefore, pGSN interferes with PAF- and LPA-induced cellular activation in vitro, suggesting a mechanism for the protective role of pGSN in vivo.
|
|
| 23. |
|
|
| 24. |
- Martner, Anna, 1979, et al.
(författare)
-
Pneumolysin released during Streptococcus pneumoniae autolysis is a potent activator of intracellular oxygen radical production in neutrophils
- 2008
-
Ingår i: Infection and Immunity. - 1098-5522. ; 76:9, s. 4079-87
-
Tidskriftsartikel (refereegranskat)abstract
- Streptococcus pneumoniae is a major cause of otitis media, pneumonia, meningitis, and septicemia in humans. The host defense against this pathogen largely depends on bacterial killing by neutrophils. A peculiar property of pneumococci is their tendency to undergo autolysis, i.e., autoinduced disruption of the bacterial cell wall mediated by activation of the enzyme LytA, under stationary growth conditions. LytA is a virulence factor, but the molecular background for this has not been fully clarified. Here we examine how bacterial compounds released upon autolysis affect the production of reactive oxygen species (ROS) in neutrophils. We found that the S. pneumoniae strains A17 and D39 induced activation of the NADPH oxidase and the production of ROS in human neutrophils and that this activation was blocked when LytA was inactivated. The ROS-inducing bacterial substance released from autolyzed bacteria was identified as the cytoplasmic toxin pneumolysin. Further screening of clinical pneumococcal strains of various sero- and genotypes revealed that selected strains expressing toxins with reduced pneumolysin-dependent hemolytic activity had decreased abilities to induce ROS in neutrophils. Furthermore, a mutated form of purified pneumolysin lacking hemolytic and complement binding functions (PdT) did not induce any oxygen radical production. The ROS produced in response to pneumolysin formed mainly intracellularly, which may explain why this production was not detected previously. ROS released intracellularly may function as signaling molecules, modifying the function of neutrophils in bacterial defense.
|
|
| 25. |
|
|
