Browsing Artikler, rapporter og annet (arktisk og marin biologi) by Author
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Browsing Artikler, rapporter og annet (arktisk og marin biologi) by Author
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Janhunen, Matti; Rudolfsen, Geir; Kekäläinen, Jukka; Figenschou, Lars; Peuhkuri, Nina; Kortet, Raine (Journal article; Tidsskriftartikkel; Peer reviewed, 2009)[+][-]
Abstract: The modern theories of sexual selection predict that male sexual ornaments may have evolved as reliable signals of male fertilization efficiency. However, among the studies of fishes with external fertilization, the results have yielded ambiguous evidence. In the present study, we present data on the phenotypic relationships between red spawning coloration and ejaculate quality (spermatocrit, sperm motility) from Arctic charr, Salvelinus alpinus. We studied two generations (F1 and F2) of males from a large lake population, reared in a standardized hatchery environment, to determine whether differential hatchery history, or duration of hatchery selection, affected the variation in ejaculate characteristics or abdominal coloration. After controlling for body length, there was no difference between the hatchery generations in these traits. However, the degree of redness increased with fish size. We found a positive correlation between sperm velocity and sperm longevity, indicating a functional integration between these sperm features across generations. Sperm velocity was also positively correlated with male redness. Therefore, the finding obtained in the present study suggests that the carotenoid-based ornamentation in Arctic charr may provide information about differences between males in their fertilization potential URI: http://hdl.handle.net/10037/4791 File(s) in this item: 1
article.pdf (330.6Kb) -
Jensen, Louise Kiel; Carroll, Jolynn (Journal article; Tidsskriftartikkel; Peer reviewed, 30-Sep-2010)[+][-]
Abstract: Copepods of the genus Calanus are keystone species in the transfer of energy from lower to higher trophic levels of the Arctic/sub-Arctic food web. We performed experimental tests on the reproduction and feeding of Calanus spp. exposed to the water-soluble fraction (WSF) of crude oil. Fecal pellet and egg production were examined for females of C. glacialis exposed to WSF (16 EPA) concentrations of 10.4 μg l–1 (high treatment; HT), 3.6 μg l–1 (low treatment; LT) and 0 μg l–1 (control treatment; CT). We observed no significant difference in cumulative egg or fecal pellet production. Egg hatching success was examined for 2 d after transferring eggs from treatment solutions to uncontaminated seawater. Hatching success was significantly lower in the HT compared to the CT. In a second experiment, feeding of C. finmarchicus was examined after exposure for 11 and 18 d to 7.0 (HT), 3.4 (LT) or 0 (CT) μg l–1 of WSF (16-EPA). Using algae cell concentrations as a proxy for feeding success, feeding was inhibited for C. finmarchicus specimens exposed to the HT of WSF compared to the CT. Our findings indicate that adult females of C. glacialis may withstand some exposure to crude oil components but the survival of offspring is negatively affected. Reduced feeding efficiency in C. finmarchicus exposed to high concentrations of WSF provides evidence that adult specimens are sensitive to exposure to crude oil. The study expands on the limited body of knowledge of potential changes to key life history traits of Arctic Calanus species resulting from exposure to chemical compounds in crude oil. Description: This paper is part of Louise Kiel Jensen's doctoral thesis, which is available in Munin at http://hdl.handle.net/10037/3794 URI: http://hdl.handle.net/10037/2839 File(s) in this item: 1
article.pdf (274.0Kb) -
Jensen, Louise Kiel; Jæger, Iris; Honkanen, Jani O.; Caroll, JoLynn (Journal article; Tidsskriftartikkel, 2011)[+][-]
Abstract: With petroleum exploration and development expanding in the Arctic (AMAP, 2007) there is a need to obtain additional information on the ecotoxicology of Arctic organisms. Here we perform 192 hr laboratory exposure experiments on the keystone Arctic zooplankton species, Calanus finmarchicus. We trace the accumulation and depuration of two polycyclic aromatic hydrocarbons (PAHs): phenanthrene and benzo[a]pyrene (B[a]P) using 14C labeled PAH compounds. Copepods were not fed during the experiment, limiting uptake to diffusion processes alone. The lighter PAH compound, phenanthrene, accumulated rapidly in C. finmarchicus, reaching steady state within 96 h. The heavier PAH compound, B[a]P, accumulated more slowly and steady state was not reached within the 192 h exposure period. As expected, the bioconcentration factor (BCF) for B[a]P was higher than for phenanthrene in accordance with a higher octanol/water partition coefficient for B[a]P (log Kow = 6.04) compared to phenanthrene (log Kow = 4.53). However, for both compounds, log BCF was lower than log Kow that may indicate active biotransformation and excretion of the selected PAH compounds. These findings on the bio-uptake kinetics for petroleum hydrocarbons are essential for evaluating the potential consequences of an oil spill in the Arctic. Description: This is the submitted manuscript version of the paper. This paper is part of Louise Kiel Jensen's doctoral thesis, which is available in Munin at http://hdl.handle.net/10037/3794 URI: http://hdl.handle.net/10037/3802 File(s) in this item: 1
article.pdf (161.7Kb) -
Jobling, Malcolm (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)[+][-]
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Jobling, Malcolm (Journal article; Tidsskriftartikkel, 2008)[+][-]
Abstract: The theme of this issue of Fiskerikandidaten is ‘The environment’; this has become a hot topic. The word environment crops up in many different contexts; in scientific literature, in the titles of meetings and conferences, in legislative and regulatory documents, in the media and popular press and on a multitude of internet sites. Discussions about the environment often revolve around ecology, although laymen that take part in these discussions may not be aware of this. We can define ecology as the study of the relationships between organisms and their physical and biological environments, or the study of the spatial and temporal patterns of the distribution and abundance of organisms, including causes and consequences. URI: http://hdl.handle.net/10037/1870 File(s) in this item: 1
article.pdf (470.4Kb) -
Jobling, Malcolm (Journal article; Tidsskriftartikkel, 2010)[+][-]
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Jobling, Malcolm (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)[+][-]
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Jobling, Malcolm (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)[+][-]
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Jobling, Malcolm (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)[+][-]
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Jobling, Malcolm (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)[+][-]
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Junttila, Olavi; Olsen, Jorunn Elisabeth; Tsegay, Berhanu Abraha (Journal article; Tidsskriftartikkel; Peer reviewed, 2005)[+][-]
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Hytönen, Timo; Junttila, Olavi; Elomaa, Paula; Moritz, Thomas (Journal article; Tidsskriftartikkel; Peer reviewed, 11-Feb-2009)[+][-]
Abstract: Background: Differentiation of long and short shoots is an important developmental trait in several species of the Rosaceae family. However, the physiological mechanisms controlling this differentiation are largely unknown. We have studied the role of gibberellin (GA) in regulation of shoot differentiation in strawberry (Fragaria × ananassa Duch.) cv. Korona. In strawberry, differentiation of axillary buds to runners (long shoot) or to crown branches (short shoot) is promoted by long-day and short-day conditions, respectively. Formation of crown branches is a prerequisite for satisfactory flowering because inflorescences are formed from the apical meristems of the crown.
Results: We found that both prohexadione-calcium and short photoperiod inhibited runner initiation and consequently led to induction of crown branching. In both cases, this correlated with a similar decline in GA1 level. Exogenous GA3 completely reversed the effect of prohexadionecalcium in a long photoperiod, but was only marginally effective in short-day grown plants. However, transfer of GA3-treated plants from short days to long days restored the normal runner formation. This did not occur in plants that were not treated with GA3. We also studied GA signalling homeostasis and found that the expression levels of several GA biosynthetic, signalling and target genes were similarly affected by prohexadione-calcium and short photoperiod in runner tips and axillary buds, respectively.
Conclusion: GA is needed for runner initiation in strawberry, and the inhibition of GA biosynthesis leads to the formation of crown branches. Our findings of similar changes in GA levels and in GA signalling homeostasis after prohexadione-calcium and short-day treatments, and photoperiod-dependent responsiveness of the axillary buds to GA indicate that GA plays a role also in the photoperiod-regulated differentiation of axillary buds. We propose that tightly regulated GA activity may control induction of cell division in subapical tissues of axillary buds, being one of the signals determining bud fate.URI: http://hdl.handle.net/10037/2163 File(s) in this item: 1
article.pdf (1.189Mb) -
Jørgensen, Marte Holten; Ehrich, Dorothee; Schmickl, Roswitha; Koch, Marcus A.; Brysting, Anne Krag (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)[+][-]
Abstract: Effects of polyploidisation on gene flow between natural populations are little known. Central European diploid and tetraploid populations of Arabidopsis arenosa and A. lyrata are here used to study interspecific and interploidal gene flow, using a combination of nuclear and plastid markers. Ploidal levels were confirmed by flow cytometry. Network analyses clearly separated diploids according to species. Tetraploids and diploids were highly intermingled within species, and some tetraploids intermingled with the other species, as well. Isolation with migration analyses suggested interspecific introgression from tetraploid A. arenosa to tetraploid A. lyrata and vice versa, and some interploidal gene flow, which was unidirectional from diploid to tetraploid in A. arenosa and bidirectional in A. lyrata. Interspecific genetic isolation at diploid level combined with introgression at tetraploid level indicates that polyploidy may buffer against negative consequences of interspecific hybridisation. The role of introgression in polyploid systems may, however, differ between plant species, and even within the small genus Arabidopsis, we find very different evolutionary fates when it comes to introgression. URI: http://hdl.handle.net/10037/3878 File(s) in this item: 1
article.pdf (3.034Mb) -
Kekäläinen, Jukka; Figenschou, Lars; Janhunen, Matti; Kortet, Raine; Peuhkuri, Nina; Rudolfsen, Geir (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)[+][-]
Abstract: The ability of captive breeding programs to maintain genetic diversity and fitness has often been questioned. Recent studies suggest that fitness loss can be extremely rapid in various traits, but it is poorly known how captive breeding affects sperm quality and thus male fertility. We studied the potential effects of hatchery-induced selection on traits indicative of semen quality, in four generations of captive bred Arctic charr Salvelinus alpinus L. We found that the number of motile sperm cells decreased, but that the swimming velocity of the sperm increased over generations. The independent effects of inbreeding and hatchery selection on semen traits could not be separated, but since in small captive broodstocks, both of them often act together, the present results should indicate real changes of semen traits in such situations. Taken together, the present data suggest that the fitness loss in some semen traits (number of motile sperm) can be extremely rapid, but selection on other, closely related traits (swimming velocity) may delay or counteract the overall deterioration of male fertilizing ability during captivity. URI: http://hdl.handle.net/10037/4790 File(s) in this item: 1
article.pdf (196.1Kb) -
Kekäläinen, Jukka; Rudolfsen, Geir; Figenschou, Lars; Janhunen, Matti; Peuhkuri, Nina; Tamper, Nina; Kortet, Raine (Journal article; Tidsskriftartikkel; Peer reviewed, 2010)[+][-]
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Killengreen, Siw Turid; Jensvoll, Ingrid; Henden, John-André; Hamel, Sandra; Ims, Rolf Anker; Mørk, Torill; Sarre, Arne Petter; Ørjebu, Alfred; Bye, Åshild; Knutsen, Kjartan (Research report; Forskningsrapport, 2012)[+][-]
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Klemetsen, Anders (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)[+][-]
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Knutsen, Kjartan; Ims, Rolf Anker; Mørk, T.; Killengreen, Siw Turid; Langeland, K.; Yoccoz, Nigel Gilles; Henden, John-André; Ravolainen, Virve (Research report; Forskningsrapport, 2006)[+][-]
Description: Faglig årsrapport for 2006 til DN. URI: http://hdl.handle.net/10037/2521 File(s) in this item: 1
report.pdf (302.8Kb) -
Krause, Kirsten; Oetke, Svenja; Krupinska, Karin (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)[+][-]
Abstract: Changes in the developmental or metabolic state of plastids can trigger profound changes in the transcript profiles of nuclear genes. Many nuclear transcription factors were shown to be controlled by signals generated in the organelles. In addition to the many different compounds for which an involvement in retrograde signaling is discussed, accumulating evidence suggests a role for proteins in plastid-to-nucleus communication. These proteins might be sequestered in the plastids before they act as transcriptional regulators in the nucleus. Indeed, several proteins exhibiting a dual localization in the plastids and the nucleus are promising candidates for such a direct signal transduction involving regulatory protein storage in the plastids. Among such proteins, the nuclear transcription factor WHIRLY1 stands out as being the only protein for which an export from plastids and translocation to the nucleus has been experimentally demonstrated. Other proteins, however, strongly support the notion that this pathway might be more common than currently believed. URI: http://hdl.handle.net/10037/5000 File(s) in this item: 1
article.pdf (323.4Kb) -
Krause, Kirsten; Herrmann, Ullrich; Fuss, Janina; Miao, Ying; Krupinska, Karin (Journal article; Tidsskriftartikkel; Peer reviewed, 2009)[+][-]
Abstract: Whirly proteins belong to a small family of proteins with a characteristic secondary structure and a conserved DNA binding domain that is found mainly in angiosperms. At least one member of the Whirly protein family, Whirly1, is dually targeted to the nucleus and to the chloroplasts and it was shown that apart from its initially described function as a transcriptional regulator of nuclear disease resistance genes, this protein comprises many more functions. It seems to fulfil roles in nuclear telomere homeostasis and possibly chloroplast rRNA metabolism as well as chloroplast intron splicing. A homologous protein with a mitochondrial presequence, Whirly2, in contrast, is presumably involved in the replication of the mitochondrial genome and in mitochondrial gene expression. In addition, it seems to affect the expression of a small subset of nuclear genes. Both Whirly proteins show an antagonistic effect on leaf senescence. Although direct evidence for a nuclear localisation of Whirly2 has yet to be obtained, we hypothesise that all members of the Whirly family are intriguing candidates for organelle-to-nucleus crosstalk with an intricate interaction between each other. URI: http://hdl.handle.net/10037/4156 File(s) in this item: 1
article.pdf (541.8Kb)
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