| 1. |
- Zamora, Juan Carlos, et al.
(författare)
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Considerations and consequences of allowing DNA sequence data as types of fungal taxa
- 2018
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Ingår i: IMA Fungus. - : INT MYCOLOGICAL ASSOC. - 2210-6340 .- 2210-6359. ; 9:1, s. 167-185
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Tidskriftsartikel (refereegranskat)abstract
- Nomenclatural type definitions are one of the most important concepts in biological nomenclature. Being physical objects that can be re-studied by other researchers, types permanently link taxonomy (an artificial agreement to classify biological diversity) with nomenclature (an artificial agreement to name biological diversity). Two proposals to amend the International Code of Nomenclature for algae, fungi, and plants (ICN), allowing DNA sequences alone (of any region and extent) to serve as types of taxon names for voucherless fungi (mainly putative taxa from environmental DNA sequences), have been submitted to be voted on at the 11th International Mycological Congress (Puerto Rico, July 2018). We consider various genetic processes affecting the distribution of alleles among taxa and find that alleles may not consistently and uniquely represent the species within which they are contained. Should the proposals be accepted, the meaning of nomenclatural types would change in a fundamental way from physical objects as sources of data to the data themselves. Such changes are conducive to irreproducible science, the potential typification on artefactual data, and massive creation of names with low information content, ultimately causing nomenclatural instability and unnecessary work for future researchers that would stall future explorations of fungal diversity. We conclude that the acceptance of DNA sequences alone as types of names of taxa, under the terms used in the current proposals, is unnecessary and would not solve the problem of naming putative taxa known only from DNA sequences in a scientifically defensible way. As an alternative, we highlight the use of formulas for naming putative taxa (candidate taxa) that do not require any modification of the ICN.
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| 2. |
- Bailey, Allison, et al.
(författare)
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Regulation of gene expression is associated with tolerance of the Arctic copepod Calanus glacialis to CO2-acidified sea water
- 2017
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Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 7:18, s. 7145-7160
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Tidskriftsartikel (refereegranskat)abstract
- Ocean acidification is the increase in seawater pCO2 due to the uptake of atmospheric anthropogenic CO2, with the largest changes predicted to occur in the Arctic seas. For some marine organisms, this change in pCO2, and associated decrease in pH, represents a climate change-related stressor. In this study, we investigated the gene expression patterns of nauplii of the Arctic copepod Calanus glacialis cultured at low pH levels. We have previously shown that organismal-level performance (development, growth, respiration) of C. glacialis nauplii is unaffected by low pH. Here, we investigated the molecular-level response to lowered pH in order to elucidate the physiological processes involved in this tolerance. Nauplii from wild-caught C. glacialis were cultured at four pH levels (8.05, 7.9, 7.7, 7.5). At stage N6, mRNA was extracted and sequenced using RNA-seq. The physiological functionality of the proteins identified was categorized using Gene Ontology and KEGG pathways. We found that the expression of 151 contigs varied significantly with pH on a continuous scale (93% downregulated with decreasing pH). Gene set enrichment analysis revealed that, of the processes downregulated, many were components of the universal cellular stress response, including DNA repair, redox regulation, protein folding, and proteolysis. Sodium:proton antiporters were among the processes significantly upregulated, indicating that these ion pumps were involved in maintaining cellular pH homeostasis. C. glacialis significantly alters its gene expression at low pH, although they maintain normal larval development. Understanding what confers tolerance to some species will support our ability to predict the effects of future ocean acidification on marine organisms.
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| 3. |
- Calosi, Piero, et al.
(författare)
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Will Life find a Way? Evolution of Marine Species Under Global Change
- 2016
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Ingår i: Evolutionary Applications. - : Wiley. - 1752-4571. ; 9:9, s. 1035-1042
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Tidskriftsartikel (refereegranskat)abstract
- Projections of marine biodiversity and implementation of effective actions for its maintenance in face of current rapid global environmental change are constrained by our limited understanding of species’ adaptive responses, including, transgenerational plasticity, epigenetics, natural selection. This special issue presents 13 novel studies, which employ experimental and modeling approaches to: (1) Investigate plastic and evolutionary responses of marine species to major global change drivers; (2) ask relevant broad eco-evolutionary questions, implementing well-designed multiple species and populations studies; (3) show the advantages of using advanced experimental designs and tools; (4) construct novel model organisms for marine evolution; (5) help identifying future challenges for the field, and (6) highlight the importance of incorporating existing evolutionary theory into management solutions for the marine realm. What emerges is that at least some populations of marine species are able to adapt to future global change conditions. However, marine organisms’ capacity for adaptation appears finite, due to evolutionary trade-offs and possible rapid losses in genetic diversity. This further corroborate the idea that acquiring an evolutionary perspective on how marine life will respond to the selective pressure of future global changes will guide us in better identifying which conservation efforts will be most needed, and most effective.
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| 4. |
- De Wit, Pierre, 1978, et al.
(författare)
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Selection on oxidative phosphorylation and ribosomal structure as a multigenerational response to ocean acidification in the common copepod Pseudocalanus acuspes
- 2016
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Ingår i: Evolutionary Applications. - : Wiley. - 1752-4571. ; 9:9, s. 1112-1223
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Tidskriftsartikel (refereegranskat)abstract
- Ocean acidification is expected to have dramatic impacts on oceanic ecosystems, yet surprisingly few studies currently examine long-term adaptive and plastic responses of marine invertebrates to pCO2 stress. Here, we exposed populations of the common copepod Pseudocalanus acuspes to three pCO2 regimes (400, 900 and 1550 μatm) for two generations, after which we conducted a reciprocal transplant experiment. A de novo transcriptome was assembled, annotated, and gene expression data revealed that genes involved in RNA transcription were strongly down-regulated in populations with long-term exposure to a high pCO2 environment, even after transplantation back to control levels. In addition, 747,000 SNPs were identified, out of which 1513 showed consistent changes in nucleotide frequency between replicates of control and high pCO2 populations. Functions involving RNA transcription and ribosomal function, as well as ion transport and oxidative phosphorylation were highly overrepresented. We thus conclude that pCO2 stress appears to impose selection in copepods on RNA synthesis and translation, possibly modulated by helicase expression. Using a physiological hypothesis-testing strategy to mine gene expression data, we herein increase the power to detect cellular targets of ocean acidification. This novel approach seems promising for future studies of effects of environmental changes in ecologically important non- model organisms.
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| 5. |
- Thor, Peter, 1965, et al.
(författare)
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Contrasting physiological responses to future ocean acidification among Arctic copepod populations : Contrasting responses to ocean acidification
- 2018
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 24:1
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Tidskriftsartikel (refereegranskat)abstract
- Widespread ocean acidification (OA) is modifying the chemistry of the global ocean, and the Arctic is recognised as the region where the changes will progress at the fastest rate. Moreover, Arctic species show lower capacity for cellular homeostasis and acid-base regulation rendering them particularly vulnerable to OA. In the present study, we found physiological differences in OA response across geographically separated populations of the keystone Arctic copepod Calanus glacialis. In copepodite stage CIV, measured reaction norms of ingestion rate and metabolic rate showed severe reductions in ingestion and increased metabolic expenses in two populations from Svalbard (Kongsfjord and Billefjord) whereas no effects were observed in a population from the Disko Bay, West Greenland. At pHT 7.87, which has been predicted for the Svalbard west coast by year 2100, these changes resulted in reductions in scope for growth of 19% in the Kongsfjord and a staggering 50% in the Billefjord. Interestingly, these effects were not observed in stage CV copepodites from any of the three locations. It seems that CVs may be more tolerant to OA perhaps due to a general physiological reorganisation to meet low intracellular pH during hibernation. Needless to say, the observed changes in the CIV stage will have serious implications for the C. glacialis population health status and growth around Svalbard. However, OA tolerant populations such as the one in the Disko Bay could help to alleviate severe effects in C. glacialis as a species.
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| 6. |
- Thor, Peter, 1965, et al.
(författare)
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Transgenerational effects alleviate severe fecundity loss during ocean acidification in a ubiquitous planktonic copepod
- 2015
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 21:6, s. 2261-2271
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Tidskriftsartikel (refereegranskat)abstract
- Ocean acidification (OA) caused by anthropogenic CO2 emission is projected for thousands of years to come, and significant effects are predicted for many marine organisms. While significant evolutionary responses are expected during such persistent environmental change, most studies consider only short term effects. Little is known about the transgenerational effects of parental environments or natural selection on the capacity of populations to counter detrimental OA effects. In the present study, six laboratory populations of the calanoid copepod Pseudocalanus acuspes were established at three different CO2 partial pressures (pCO2 of 400, 900 and 1550 μatm) and grown for two generations at these conditions. Our results show evidence of alleviation of OA effects as a result of transgenerational effects in P. acuspes. Second generation adults showed a 29% decrease in fecundity at 900 μatm CO2 compared to 400 μatm CO2. This was accompanied by a 10% increase in metabolic rate indicative of metabolic stress. Reciprocal transplant tests demonstrated that this effect was reversible and the expression of phenotypic plasticity. Furthermore, these tests showed that at a pCO2 exceeding the natural range experienced by P. acuspes (1550 μatm), fecundity would have decreased by as much as 67% compared to at 400 μatm CO2 as a result of this plasticity. However, transgenerational effects partly reduced OA effects so that the loss of fecundity remained at a level comparable to that at 900 μatm CO2. This also relieved the copepods from metabolic stress, and respiration rates were lower than at 900 μatm CO2. These results highlight the importance of tests for transgenerational effects to avoid over-estimation of the effects of OA.
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| 7. |
- Wendt, Ida, 1981, et al.
(författare)
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INFLUENCE OF PREY SPECIES AND CONCENTRATION ON EGG PRODUCTION EFFICIENCY AND HATCHING SUCCESS IN ACARTIA TONSA DANA (COPEPODA, CALANOIDA)
- 2015
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Ingår i: Crustaceana. - : Brill. - 0011-216X .- 1568-5403. ; 88:6, s. 675-687
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Tidskriftsartikel (refereegranskat)abstract
- We measured ingestion rate (IR), egg production rate (EPR) and egg hatching success (EHS) at increasing prey concentrations and calculated egg production efficiency (EPE) and maintenance rate (MR) in the estuarine copepod Acartia tonsa fed three different algal diets. EPR and EHS were relatively more affected by prey species than by prey concentration. EPEs were constant among carbon concentrations (C) on a diet of Rhodomonas baltica (0.202 +/- 0.055, mean +/- SD) and Dunaliella tertiolecta (0.034 +/- 0.015), but decreased significantly from 0.371 +/- 0.062 (mean of two lowest prey concentrations) to 0.200 +/- 0.019 at the highest concentration of Thalassiosira weissflogii. In general it seems that other requirements than C demand limit EPE and EHS in A. tonsa. The MR (IR when EPR = 0) was significantly higher on D. tertiolecta, which also yielded the lowest EPEs, and it seems that variations in maintenance requirements may have been instrumental in evoking EPE variations as well.
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