| 1. |
- Carney Almroth, Bethanie, 1974, et al.
(författare)
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Gender differences in health and aging of Atlantic cod subject to size selective fishery
- 2012
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Ingår i: Biology Open. - : The Company of Biologists. - 2046-6390. ; 1:9, s. 922-928
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Tidskriftsartikel (refereegranskat)abstract
- We have analyzed health and physiological aging parameters in male and female Atlantic cod, Gadus morhua, captured in Kattegat, Skagerrak and in Öresund. Gender differences were clearly evident in a number of variables. Males had longer liver telomeres and higher catalase activities than females, while females had higher superoxide dismutase activity, liver somatic index and condition factor. Effects of age were found for males where levels of the antioxidant glutathione and telomere length declined with age, indicating physiological aging. Liver somatic index increased and percentage oxidized glutathione decreased with age. Between-site comparisons of males show that percentage oxidized glutathione and catalase were lowest in Kattegat, whereas protein carbonyls and condition factor were higher in Skagerrak. Females, on the other hand, showed no differences between sites or indications of somatic aging or age-related effects in egg quality, indicating that older and larger female cod are healthy and show no changes in eggs with age. In contrast, males showed indications of physiological aging and lower condition than females. The results emphasize the importance of conserving old mature fish, in particular high egg-productive females, when managing fisheries.
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| 2. |
- Nilsson Sköld, Helen, 1970, et al.
(författare)
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Telomerase deficiency in a colonial ascidian after prolonged asexual propagation
- 2011
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Ingår i: Journal of experimental zoology B (Mol Dev Evol). ; 314B
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT In organisms that propagate by agametic cloning, the parental body is the reproductive unit and fitness increases with clonal size, so that colonial metazoans, despite lack of experimental data, have been considered potentially immortal. Using asexual propagation rate as a measure of somatic performance, and telomerase activity and relative telomere length as molecular markers of senescence, old (7-12 yr) asexual strains of a colonial ascidian, Diplosoma listerianum, were compared with their recent sexually produced progeny. We report for the first time evidence for long-term molecular senescence in asexual lineages of a metazoan, and that only passage between sexual generations provides total rejuvenation permitting indefinite propagation and growth. Thus, this colonial ascidian has not fully escaped ageing. The possibility of somatic replicative senescence also potentially helps to explain why metazoans with the capacity for asexual propagation through gametic cloning commonly undergo cycles of sexual reproduction in the wild.
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| 3. |
- Hernroth, Bodil, 1951, et al.
(författare)
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Possibility of Mixed Progenitor Cells in Sea Star Arm Regeneration
- 2010
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Ingår i: Journal of Experimental Zoology Part B-Molecular and Developmental Evolution. - : Wiley. - 1552-5007 .- 1552-5015. ; 314B:6, s. 457-468
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Tidskriftsartikel (refereegranskat)abstract
- In contrast to most vertebrates, invertebrate deuterostome echinoderms, such as the sea star Asterias rubens, undergo regeneration of lost body parts. The current hypothesis suggests that differentiated cells are the main source for regenerating arm in sea stars, but there is little information regarding the origin and identity of these cells. Here, we show that several organs distant to the regenerating arm responded by proliferation, most significantly in the coelomic epithelium and larger cells of the pyloric caeca. Analyzing markers for proliferating cells and parameters indicating cell ageing, such as levels of DNA damage, pigment, and lipofuscin contents as well as telomere length and telomerase activity, we suggest that cells contributing to the new arm likely originate from progenitors rather than differentiated cells. This is the first study showing that cells of mixed origin may be recruited from more distant sources of stem/progenitor cells in a sea star, and the first described indication of a role for pyloric caeca in arm regeneration. Data on growth rate during arm regeneration further indicate that regeneration is at the expense of whole animal growth. We propose a new working hypothesis for arm regeneration in sea stars involving four phases: wound healing by coelomocytes, migration of distant progenitor cells of mixed origin including from pyloric caeca, proliferation in these organs to compensate for cell loss, and finally, local proliferation in the regenerating arm J. Exp. Zool. (Mol. Dev. Evol.) 3148:457-468, 2010. (C) 2010 Wiley-Liss, Inc.
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| 4. |
- Hernroth, Bodil, 1951, et al.
(författare)
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Simulated climate change causes immune suppression and protein damage in the crustacean Nephrops norvegicus
- 2012
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Ingår i: Fish & Shellfish Immunology. - : Elsevier BV. - 1050-4648 .- 1095-9947. ; 33:5, s. 1095-1101
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Tidskriftsartikel (refereegranskat)abstract
- Rising atmospheric carbon dioxide concentration is causing global warming, which affects oceans by elevating water temperature and reducing pH. Crustaceans have been considered tolerant to ocean acidification because of their retained capacity to calcify during subnormal pH. However, we report here that significant immune suppression of the Norway lobster, Nephrops norvegicus, occurs after a 4-month exposure to ocean acidification (OA) at a level predicted for the year 2100 (hypercapnic seawater with a pH lowered by 0.4 units). Experiments carried out at different temperatures (5, 10, 12, 14, 16, and 18 °C) demonstrated that the temperature within this range alone did not affect lobster immune responses. In the OA-treatment, hemocyte numbers were reduced by almost 50% and the phagocytic capacity of the remaining hemocytes was inhibited by 60%. The reduction in hemocyte numbers was not due to increased apoptosis in hematopoetic tissue. Cellular responses to stress were investigated through evaluating advanced glycation end products (AGE) and lipid oxidation in lobster hepatopancreata, and OA-treatment was shown to significantly increase AGEs', indicating stress-induced protein alterations. Furthermore, the extracellular pH of lobster hemolymph was reduced by approximately 0.2 units in the OA-treatment group, indicating either limited pH compensation or buffering capacity. The negative effects of OA-treatment on the nephropidae immune response and tissue homeostasis were more pronounced at higher temperatures (12–18 °C versus 5 °C), which may potentially affect disease severity and spread. Our results signify that ocean acidification may have adverse effects on the physiology of lobsters, which previously had been overlooked in studies of basic parameters such as lobster growth or calcification.
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| 7. |
- Nilsson Sköld, Helen, 1970, et al.
(författare)
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Rapid color change in fish and amphibians - function, regulation, and emerging applications.
- 2013
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Ingår i: Pigment Cell & Melanoma Research. - : Wiley. - 1755-1471 .- 1755-148X. ; 26:1, s. 29-38
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Forskningsöversikt (refereegranskat)abstract
- Physiological color change is important for background matching, thermoregulation as well as signaling and is in vertebrates mediated by synchronous intracellular transport of pigmented organelles in chromatophores. We describe functions of and animal situations where color change occurs. A summary of endogenous and external factors that regulate this color change in fish and amphibians is provided, with special emphasis on extracellular stimuli. We describe not only color change in skin, but also highlight studies on color change that occurs using chromatophores in other areas such as iris and on the inside of the body. In addition, we discuss the growing field that applies melanophores and skin color in toxicology and as biosensors, and point out research areas with future potential.
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| 8. |
- Nilsson Sköld, Helen, 1970
(författare)
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Sexuell eller klonal förökning, det är frågan!
- 2013
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Ingår i: Havsutsikt. - 1104-0513. ; 1, s. 18-19
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Att föröka sig sexuellt är krångligt och bryter lyckosamma genkombinationer. Trots det är det den absolut vanligaste formen av reproduktion i både djur- och växtriket. Att klona sig verkar dock vara bra på kort sikt och för enskilda individer. Varför sexuell reproduktion dominerar är en av de gamla klassiska frågorna inom biologin. Jag har här gett mig ut i naturen för att fråga några marina arter varför de gör som de gör !
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| 9. |
- Nilsson Sköld, Helen, 1970, et al.
(författare)
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Skin Biopsies as Tools to Measure Fish Coloration and Colour Change
- 2011
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Ingår i: InTech. ; , s. 1-18
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- A biopsy is a link between the whole organism and its cells. Many recent advances in the field of fish coloration have been gained through experimentation on skin biopsies. In particular, this strategy has allowed the in-depth knowledge from pigment cell physiology to be applied to wider topics, such as behavioral ecology. Moreover, melanophores from fish and frogs have long served as models for a general understanding of intracellular transport and organelle positioning. For this purpose, fish skin biopsies have frequently been used for isolation of pigment cells but also for isolation of fibroblasts. In fish pigmentation research, skin biopsies have also been used to understand what causes changes in the skin's overall appearance, especially in the context of short or long-term modulation of tissue coloration. Examples of this are how many fishes rapidly change their colour during courtship or aggressive displays. Here, we review our methodology for the use of skin biopsies in research on fish coloration – from pigment cell physiology to animal behavior. We also highlight some of the most significant findings from this research, and present unsolved issues and suggestions for future directions. In this chapter, we will provide a description of the experimental procedures we have used to manipulate and analyze fish skin biopsies in the context of fish coloration - from chromatophores to animal behavior. Since our research has mainly focused on marine fishes, the protocols (e.g. the choice of buffers) were chosen to suit such animals. However, with minor modifications, these methods will likely work also on most fresh water species. Many of the experimental procedures are fast to assess and easy to perform, and we therefore encourage the experimentation on fish biopsies for use in education. The protocols described in this chapter are also suitable for such exercises.
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