| 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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Stem Cells in Asexual Reproduction of Marine Invertebrates
- 2009
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Ingår i: Stem Cells in Marine Organisms. - Netherlands : Springer. - 9789048127665 ; , s. 105-137
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- While sexual reproduction is conserved and almost ubiquitous, asexual reproduction in forms of parthenogenesis or agametic cloning from somatic tissue is less conserved. The phylogeny shows that agametic cloning is widespread but scattered with many different modes for asexual formation of a new animal. This suggests that independent forms of cloning have evolved later from sexual ancestors between and within different phyla. Here, we present an overview of agametic cloning in the marine animal kingdom and discuss molecular and evolutionary aspects of somatic stem cell usage for asexual cloning. The molecular tissue characterizations and the relative role of different stem cells involved in agametic cloning are only at its beginning with whole phyla largely uncovered. An emerging hypothesis is that the first somatic stem cells used in cloning were also able to form a germ-line and that the more limited lineage specific stem cells are derived. We discuss advantages and problems with agametic cloning from somatic tissue and propose that the levels of stem cell potential held in the tissue can have large consequences for the reproductive life cycle strategies and long-term fitness in clonal animals and strains. We finally describe suitable molecular experimental approaches for future research on this topic.
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| 3. |
- 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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| 4. |
- Thorndyke, Michael C., 1946, et al.
(författare)
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Marine ecological genomics: when genomics meets marine ecology
- 2007
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Ingår i: Marine Ecology Progress Series. - 0171-8630. ; 332, s. 257-273
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Tidskriftsartikel (refereegranskat)abstract
- Genomics, proteomics and metabolomics (the ’omic’ technologies) have revolutionized the way we work and are able to think about working, and have opened up hitherto unimagined opportunities in all research fields. In marine ecology, while ‘standard’ molecular and genetic approaches are well known, the newer technologies are taking longer to make an impact. In this review we explore the potential and promise offered by genomics, genome technologies, expressed sequence tag (EST) collections, microarrays, proteomics and bar coding for modern marine ecology. Methods are succinctly presented with both benefits and limitations discussed. Through examples from the literature, we show how these tools can be used to answer fundamental ecological questions, e.g. ‘what is the relationship between community structure and ecological function in ecosystems?’; ‘how can a species and the phylogenetic relationship between taxa be identified?’; ‘what are the factors responsible for the limits of the ecological niche?’; or ‘what explains the variations in life-history patterns among species?’ The impact of ecological ideas and concepts on genomic science is also discussed.
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| 5. |
- Andersson, Tony, 1973-, et al.
(författare)
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Phosphoinositide 3-kinase is involved in Xenopus and Labrus melanophore aggregation
- 2003
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Ingår i: Cellular Signalling. - 0898-6568 .- 1873-3913. ; 15:12, s. 1119-1127
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Tidskriftsartikel (refereegranskat)abstract
- Melanophores are pigmented cells capable of quick colour changes through coordinated transport of their intracellular pigment granules. We demonstrate the involvement of phosphoinositide 3-kinase (PI3-K) in Xenopus and Labrus aggregation by the use of the PI3-K inhibitor, LY-294002. In Xenopus, wortmannin-insensitive PI3-K was found to be essential for the aggregation, mitogen-activated protein kinase (MAPK) activation and tyrosine phosphorylation of a 280-kDa protein, and for the maintenance of low cyclic adenosine 3':5'-monophosphate (cAMP) during the aggregated state. Pre-aggregated cells disperse completely to LY-294002 at 50-100 muM, involving a transient elevation in cAMP due to adenylate cyclase (AC) stimulation or to inhibition of cyclic nucleotide phosphodiesterase (PDE). The inactive analogue LY-303511 did not induce dispersion at the same concentrations. PDE4 and/or PDE2 was found to be involved in melanosome aggregation. The similar kinetics of LY-294002 and various PDE inhibitors indicates that the elevation of cAMP might be due to inhibition of PDE. In Labrus melanophores, LY-294002 had a less dramatic effect, probably due to less dependence on PDE in regulation of cAMP levels. In Xenopus aggregation, we suggest that melatonin stimulation of the Mel1c receptor via G(betagamma) activates PI3-K that, directly or indirectly via MAPK, activates PDE. (C) 2003 Elsevier Inc. All rights reserved.
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| 6. |
- Aspengren, Sara, 1977, et al.
(författare)
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Different strategies for color change
- 2009
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Ingår i: Cellular and Molecular Life Sciences (CMLS). - : Springer Science and Business Media LLC. - 1420-682X .- 1420-9071. ; 66, s. 187-191
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Forskningsöversikt (refereegranskat)
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| 7. |
- Aspengren, Sara, 1977, et al.
(författare)
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New Insights into Melanosome Transport in Vertebrate Pigment Cells
- 2008
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Ingår i: INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY, Vol 272 (edited by Kwang W. Jeon). - : Elsevier. - 9780123747471 ; 272, s. 245-302
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Pigment cells of lower vertebrates provide an excellent model to study organelle transport as they specialize in the translocation of pigment granules in response to defined chemical cues. This review will focus on the well-studied melanophore/melanocyte systems in fish, amphibians, and mammals. We will describe the roles of melanin, melanophores, and melanocytes in animals, current views on how the three motor proteins dynein, kinesin, and myosin-V are involved in melanosome transport along microtubules and actin filaments, and how signal transduction pathways regulate the activities of the motors to achieve aggregation and dispersion of melanosomes. We will also describe how melanosomes are transferred to surrounding skin cells in amphibians and mammals. Comparative studies have revealed that the ability of physiological color change is lost during evolution while the importance of morphological color change, mainly via transfer of pigment to surrounding skin cells, increases. In humans, pigment mainly has a role in protection against ultraviolet radiation, but also perhaps in the immune system.
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| 8. |
- Aspengren, Sara, 1977, et al.
(författare)
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Noradrenaline- and melatonin-mediated regulation of pigment aggregation in fish melanophores
- 2003
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Ingår i: Pigment Cell Research. - : Wiley. - 0893-5785. ; 16:1, s. 59-64
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Tidskriftsartikel (refereegranskat)abstract
- The effects of melatonin and noradrenaline (NA) on bi-directional melanosome transport were analysed in primary cultures of melanophores from the Atlantic cod. Both agents mediated rapid melanosome aggregation, and by using receptor antagonists, melatonin was found to bind to a melatonin receptor whereas NA binds to an α2-adrenoceptor. It has previously been stated that melatonin-mediated melanosome aggregation in Xenopus is coupled with tyrosine phosphorylation of a so far unidentified high molecular weight protein and we show that although acting through different receptors and through somewhat different downstream signalling events, tyrosine phosphorylation is of the utmost importance for melanosome aggregation mediated by both NA and melatonin in cod melanophores. Together with cyclic adenosine 3-phosphate-fluctuations, tyrosine phosphorylation functions as a switch signal for melanosome aggregation and dispersion in these cells.
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| 9. |
- Cortesi, F., et al.
(författare)
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Phenotypic Plasticity Confers Multiple Fitness Benefits to a Mimic
- 2015
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Ingår i: Current Biology. - : Elsevier BV. - 0960-9822. ; 25:7, s. 949-954
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Tidskriftsartikel (refereegranskat)abstract
- Animal communication is often deceptive; however, such dishonesty can become ineffective if it is used too often, is used out of context, or is too easy to detect [1-3]. Mimicry is a common form of deception, and most mimics gain the greatest fitness benefits when they are rare compared to their models [3, 4]. If mimics are encountered too frequently or if their model is absent, avoidance learning of noxious models is disrupted (Batesian mimicry [3]), or receivers become more vigilant and learn to avoid perilous mimics (aggressive mimicry [4]). Mimics can moderate this selective constraint by imperfectly resembling multiple models [5], through polymorphisms [6], or by opportunistically deploying mimetic signals [1, 7]. Here we uncover a novel mechanism to escape the constraints of deceptive signaling: phenotypic plasticity allows mimics to deceive targets using multiple guises. Using a combination of behavioral, cell histological, and molecular methods, we show that a coral reef fish, the dusky dottyback (Pseudochromis fuscus), flexibly adapts its body coloration to mimic differently colored reef fishes and in doing so gains multiple fitness benefits. We find that by matching the color of other reef fish, dottybacks increase their success of predation upon juvenile fish prey and are therefore able to deceive their victims by resembling multiple models. Furthermore, we demonstrate that changing color also increases habitat-associated crypsis that decreases the risk of being detected by predators. Hence, when mimics and models share common selective pressures, flexible imitation of models might inherently confer secondary benefits to mimics. Our results show that phenotypic plasticity can act as a mechanism to ease constraints that are typically associated with deception.
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| 10. |
- Franco-Belussi, Lilian, et al.
(författare)
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Internal pigment cells respond to external UV radiation in frogs
- 2016
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Ingår i: Journal of Experimental Biology. - : The Company of Biologists. - 0022-0949 .- 1477-9145. ; 219:9, s. 1378-1383
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Tidskriftsartikel (refereegranskat)abstract
- Fish and amphibians have pigment cells that generate colorful skins important for signaling, camouflage, thermoregulation and protection against ultraviolet radiation (UVR). However, many animals also have pigment cells inside their bodies, on their internal organs and membranes. In contrast to external pigmentation, internal pigmentation is remarkably little studied and its function is not well known. Here, we tested genotoxic effects of UVR and its effects on internal pigmentation in a neotropical frog, Physalaemus nattereri. We found increases in body darkness and internal melanin pigmentation in testes and heart surfaces and in the mesenterium and lumbar region after just a few hours of UVR exposure. The melanin dispersion in melanomacrophages in the liver and melanocytes in testes increased after UV exposure. In addition, the amount of melanin inside melanomacrophages cells also increased. Although mast cells were quickly activated by UVR, only longer UVR exposure resulted in genotoxic effects inside frogs, by increasing the frequency of micronuclei in red blood cells. This is the first study to describe systemic responses of externalUVRon internal melanin pigmentation, melanomacrophages and melanocytes in frogs and thus provides a functional explanation to the presence of internal pigmentation.
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