| 1. |
- Lind, Ulrika, et al.
(författare)
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Molecular Characterization of the alpha-Subunit of Na+/K+ ATPase from the Euryhaline Barnacle Balanus improvisus Reveals Multiple Genes and Differential Expression of Alternative Splice Variants
- 2013
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 8:10
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Tidskriftsartikel (refereegranskat)abstract
- The euryhaline bay barnacle Balanus improvisus has one of the broadest salinity tolerances of any barnacle species. It is able to complete its life cycle in salinities close to freshwater (3 PSU) up to fully marine conditions (35 PSU) and is regarded as one of few truly brackish-water species. Na+/K+ ATPase (NAK) has been shown to be important for osmoregulation when marine organisms are challenged by changing salinities, and we therefore cloned and examined the expression of different NAKs from B. improvisus. We found two main gene variants, NAK1 and NAK2, which were approximately 70% identical at the protein level. The NAK1 mRNA existed in a long and short variant with the encoded proteins differing only by 27 N-terminal amino acids. This N-terminal stretch was coded for by a separate exon, and the two variants of NAK1 mRNAs appeared to be created by alternative splicing. We furthermore showed that the two NAK1 isoforms were differentially expressed in different life stages and in various tissues of adult barnacle, i.e the long isoform was predominant in cyprids and in adult cirri. In barnacle cyprid larvae that were exposed to a combination of different salinities and pCO(2) levels, the expression of the long NAK1 mRNA increased relative to the short in low salinities. We suggest that the alternatively spliced long variant of the Nak1 protein might be of importance for osmoregulation in B. improvisus in low salinity conditions.
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| 2. |
- Wrange, Anna-Lisa, 1981
(författare)
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From geography to genes: evolutionary perspectives on salinity tolerance in the brackish water barnacle Balanus improvisus
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- How species respond to changes in their environment is a fundamental question in biology. This has become an increasingly important issue as anthropogenic effects of climate change and biological invasions have major impacts on marine ecosystems worldwide. In this thesis I investigated the role of salinity tolerance from an evolutionary perspective, using a wide range of techniques, spanning from population genetics and common-garden experiments to characterizing potential genes involved in osmoregulation in barnacles. I used the acorn barnacle species Balanus (Amphibalanus) improvisus, which displays a remarkably broad salinity tolerance, to investigate how this trait has influenced the species' potential to establish in new environments, and respond to projected near-future salinity reductions in coastal seas. I also examined physiological and molecular mechanisms that may be involved in osmoregulation in B. improvisus. I further analysed population genetic structure using microsatellites and mitochondrial DNA, and related the results to anthropogenic and natural dispersal dynamics on both global and regional (Baltic Sea) scales. I found high genetic diversity in most populations, with many shared haplotypes between distant populations. This supports the hypothesis that maritime shipping is an important vector for the dispersal of the cosmopolitan species B. improvisus. Nonetheless, natural larval dispersal is also important on smaller geographical scales, such as within the Baltic Sea. Marked genetic differentiation between northern and southern Baltic Sea populations raises the question whether there is restricted gene flow within the Baltic Sea, creating potential for local adaptations to evolve. To investigate the extent to which the broad distribution of B. improvisus along the Baltic Sea salinity gradient is explained by local adaptation versus physiological plasticity, I performed a common-garden experiment in which multiple populations were exposed to different salinities and multiple fitness-related phenotypic traits were recorded. The experiment confirmed that phenotypic plasticity, rather than local adaptation, explained the broad distribution of the species along the salinity gradient. Interestingly, all populations of B. improvisus performed best at low and intermediate salinities in many fitness-related traits (survival, growth and reproduction), although other traits (e.g. shell strength an juvenile growth) indicated higher costs associated with low salinity. A candidate gene approach was used to investigate the molecular basis of broad salinity tolerance in B. improvisus by characterizing the Na+/K+ ATPase (NAK) of B. improvisus – an ion transporter commonly involved in active osmoregulation in many species. We identified two main gene variants in B. improvisus (NAK1 and NAK2), and found that NAK1 mRNA existed in two isoforms that were differentially expressed in different life stages and adult tissues, suggesting an active role in osmoregulation. Lastly, I summarise current knowledge about salinity tolerance in barnacles and outline new research directions to further our understanding of the physiological and molecular mechanisms involved in salinity tolerance in barnacles.
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| 3. |
- Wrange, Anna-Lisa
(författare)
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Havstulpanprojektet på västkusten 2012 : En studie om påväxtdynamik i norra Bohuslän under båtsäsongen 2012
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Ett vanligt sätt att motverka problem med påväxt på båtar är att måla med båtbottenfärger. Men det finns många miljörelaterade problem med användandet av dessa färger och trots omfattande forskning under de senaste åren finns inget effektivt och helt miljövänligt färgalternativ på marknaden idag. Alternativa metoder omfattar mekanisk rengöring, exempelvis med hjälp av högtryckstvätt på spolplatta, eller landförvaring. Sedan år 2001 har Skärgårdsstiftelsen i Stockholm drivit ett projekt som syftar till att minska användandet av giftiga båtbottenfärger genom ett övervakningsprogram med information till allmänheten om när det har satt sig havstulpaner och det är dags att tvätta båten. Längs stora delar av Östersjökusten, där påväxten av havstulpaner är begränsad till ett fåtal tillfällen under båtsäsongen, har detta fungerat relativt bra. På västkusten däremot, är påväxtdynamiken generellt mer komplex, med fler påväxtarter och tätare larvsettlingsperioder under båtsäsongen. Dock finns få studier som kvantitativt har undersökt påväxten längs västkusten samt hur detta varierar under en hel båtsäsong. Syftet med denna studie var därför att i fält dokumentera påväxtdynamiken längs den svenska västkusten under båtsäsongen 2012 samt utvärdera potentialen för att använda mekanisk rengöring av båtar i större utsträckning längs västkusten. Som förväntat, observerades högre artrikedom av påväxt längs västkusten jämfört med vad som normalt förekommer längs ostkusten. Påväxten dominerades av havstulpaner, sjöpungar och musslor, men även mossdjur, hydroider och fintrådiga alger etablerade sig på panelerna. Stor variation i artsammansättning och intensitet av påväxt observerades mellan olika närliggande lokaler, men främst på paneler som hängt i fält i minst fyra veckor. Nysettlade havstulpaner observerades vid varje undersökningstillfälle (d.v.s. varannan vecka) under hela båtsäsongen (dock främst i juni-augusti) vilket indikerar kontinuerlig rekrytering under hela perioden. Påväxten på panelerna överensstämde relativt väl med båtskroven, särskilt under den första tiden efter utplacering i havet. Utifrån resultaten i denna studie skulle rengöring av båtskrov i norra Bohuslän behövas varannan till var fjärde vecka för att hålla svårhanterlig påväxt borta och underlätta rengöring med enklare mekaniska metoder. Projektet var ett samarbete mellan Skärgårdsstiftelsen i Stockholms län och Göteborgs Universitet, med finansiering genom Hav- och vattenmyndigheten.
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| 4. |
- Wrange, Anna-Lisa, 1981, et al.
(författare)
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Importance of plasticity and local adaptation for coping with changing salinity in coastal areas: a test case with barnacles in the Baltic Sea
- 2014
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Ingår i: BMC Evolutionary Biology. - : Springer Science and Business Media LLC. - 1471-2148. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Salinity plays an important role in shaping coastal marine communities. Near-future climate predictions indicate that salinity will decrease in many shallow coastal areas due to increased precipitation; however, few studies have addressed this issue. The ability of ecosystems to cope with future changes will depend on species’ capacities to acclimatise or adapt to new environmental conditions. Here, we investigated the effects of a strong salinity gradient (the Baltic Sea system – Baltic, Kattegat, Skagerrak) on plasticity and adaptations in the euryhaline barnacle Balanus improvisus. We used a common-garden approach, where multiple batches of newly settled barnacles from each of three different geographical areas along the Skagerrak-Baltic salinity gradient were exposed to corresponding native salinities (6, 15 and 30 PSU), and phenotypic traits including mortality, growth, shell strength, condition index and reproductive maturity were recorded. Results We found that B. improvisus was highly euryhaline, but had highest growth and reproductive maturity at intermediate salinities. We also found that low salinity had negative effects on other fitness-related traits including initial growth and shell strength, although mortality was also lowest in low salinity. Overall, differences between populations in most measured traits were weak, indicating little local adaptation to salinity. Nonetheless, we observed some population-specific responses – notably that populations from high salinity grew stronger shells in their native salinity compared to the other populations, possibly indicating adaptation to differences in local predation pressure. Conclusions Our study shows that B. improvisus is an example of a true brackish-water species, and that plastic responses are more likely than evolutionary tracking in coping with future changes in coastal salinity.
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