| 1. |
- Nilsen, Tom O, et al.
(författare)
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Differential expression of gill Na+,K+-ATPase alpha- and beta-subunits, Na+,K+,2Cl- cotransporter and CFTR anion channel in juvenile anadromous and landlocked Atlantic salmon Salmo salar.
- 2007
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Ingår i: The Journal of experimental biology. - : The Company of Biologists. - 0022-0949 .- 1477-9145. ; 210:Pt 16, s. 2885-96
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Tidskriftsartikel (refereegranskat)abstract
- This study examines changes in gill Na(+),K(+)-ATPase (NKA) alpha- and beta-subunit isoforms, Na(+),K(+),2Cl(-) cotransporter (NKCC) and cystic fibrosis transmembrane conductance regulator (CFTR I and II) in anadromous and landlocked strains of Atlantic salmon during parr-smolt transformation, and after seawater (SW) transfer in May/June. Gill NKA activity increased from February through April, May and June among both strains in freshwater (FW), with peak enzyme activity in the landlocked salmon being 50% below that of the anadromous fish in May and June. Gill NKA-alpha1b, -alpha3, -beta(1) and NKCC mRNA levels in anadromous salmon increased transiently, reaching peak levels in smolts in April/May, whereas no similar smolt-related upregulation of these transcripts occurred in juvenile landlocked salmon. Gill NKA-alpha1a mRNA decreased significantly in anadromous salmon from February through June, whereas alpha1a levels in landlocked salmon, after an initial decrease in April, remained significantly higher than those of the anadromous smolts in May and June. Following SW transfer, gill NKA-alpha1b and NKCC mRNA increased in both strains, whereas NKA-alpha1a decreased. Both strains exhibited a transient increase in gill NKA alpha-protein abundance, with peak levels in May. Gill alpha-protein abundance was lower in SW than corresponding FW values in June. Gill NKCC protein abundance increased transiently in anadromous fish, with peak levels in May, whereas a slight increase was observed in landlocked salmon in May, increasing to peak levels in June. Gill CFTR I mRNA levels increased significantly from February to April in both strains, followed by a slight, though not significant increase in May and June. CFTR I mRNA levels were significantly lower in landlocked than anadromous salmon in April/June. Gill CFTR II mRNA levels did not change significantly in either strain. Our findings demonstrates that differential expression of gill NKA-alpha1a, -alpha1b and -alpha3 isoforms may be important for potential functional differences in NKA, both during preparatory development and during salinity adjustments in salmon. Furthermore, landlocked salmon have lost some of the unique preparatory upregulation of gill NKA, NKCC and, to some extent, CFTR anion channel associated with the development of hypo-osmoregulatory ability in anadromous salmon.
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| 2. |
- Prunet, Patrick, et al.
(författare)
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Functional Genomics of Stress Responses in Fish
- 2008
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Ingår i: Reviews in fisheries science. - : Informa UK Limited. - 1064-1262 .- 1547-6553. ; 16, s. 157-166
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Tidskriftsartikel (refereegranskat)abstract
- Our understanding of the mechanisms underlying stress responses in fish remains fragmentary. However, new insights into these mechanisms and their biological significance have been provided by investigation at the transcriptional level. Microarray technology has allowed the unbiased analysis of the transcriptome, providing a potentially system-wide overview of stress responses. In this review, we present recently published transcriptomic studies on stress responses in fish exposed to a range of environmental, xenobiotic, social, and aquacultural stressors. Overall, these studies highlight the complexity of transcript patterns, have identified new genes whose expression is significantly modified after exposure to stressors, and have revealed both common and tissue-specific expression signatures. Some shortcomings can be identified, including lack of information on the longer-term compensatory or adaptive phases of the stress response, limitations on gene annotation, and the use of pooled mRNA preparations, which masks variation between individuals. Nonetheless, although the functional genomic analysis of stress responses in fish is still in its infancy, rapid growth in the number of studies and continued advances in technology and database content will inevitably lead to a fuller understanding of the processes involved and to the identification of novel stress indicators with diagnostic or predictive value.
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