| 1. |
- Eilertsen, Mariann, et al.
(författare)
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Photoreception and transcriptomic response to light during early development of a teleost with a life cycle tightly controlled by seasonal changes in photoperiod
- 2022
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Ingår i: PLOS Genetics. - : Public Library of Science. - 1553-7390 .- 1553-7404. ; 18:12
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Tidskriftsartikel (refereegranskat)abstract
- Light cues vary along the axis of periodicity, intensity and spectrum and perception of light is dependent on the photoreceptive capacity encoded within the genome and the opsins expressed. A global approach was taken to analyze the photoreceptive capacity and the effect of differing light conditions on a developing teleost prior to first feeding. The transcriptomes of embryos and alevins of Atlantic salmon (Salmo salar) exposed to different light conditions were analyzed, including a developmental series and a circadian profile. The results showed that genes mediating nonvisual photoreception are present prior to hatching when the retina is poorly differentiated. The clock genes were expressed early, but the circadian profile showed that only two clock genes were significantly cycling before first feeding. Few genes were differentially expressed between day and night within a light condition; however, many genes were significantly different between light conditions, indicating that light environment has an impact on the transcriptome during early development. Comparing the transcriptome data from constant conditions to periodicity of white light or different colors revealed overrepresentation of genes related to photoreception, eye development, muscle contraction, degradation of metabolites and cell cycle among others, and in constant light, several clock genes were upregulated. In constant white light and periodicity of green light, genes associated with DNA replication, chromatin remodeling, cell division and DNA repair were downregulated. The study implies a direct influence of light conditions on the transcriptome profile at early developmental stages, by a complex photoreceptive system where few clock genes are cycling.
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| 2. |
- Nederlof, Marit, et al.
(författare)
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Application of polychaetes in (de)coupled integrated aquaculture: an approach for fish waste bioremediation
- 2020
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Ingår i: Aquaculture Environment Interactions. - : Inter-Research Science Center. - 1869-215X .- 1869-7534. ; 12, s. 385-399
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Tidskriftsartikel (refereegranskat)abstract
- Development of benthic components within integrated multi-trophic aquaculture (IMTA) systems warrants more attention, and the development of polychaetes as an extractive component in IMTA systems is ongoing. This study estimates the bioremediation potential of Capitella sp. and Ophryotrocha craigsmithi for coupled and decoupled salmon-driven IMTA. In coupled IMTA, polychaetes receive fresh faeces, while in decoupled IMTA, preservation of faeces is applied. Respiration and ammonia excretion rates were measured for polychaetes fed fresh, oven-dried or acidified salmon faeces, and combined with nutrients incorporated into tissue growth, to estimate nutrient requirements. Nutrient requirements were subsequently used to evaluate bioremediation potential. Metabolic rates were highest for O. craigsmithi and con- tributed notably to their overall nutrient requirement (20−30%). For the 2 polychaete species, nutrient requirements ranged from 5 to 26 mg C and from 2 to 6 mg N g−1 AFDW d−1. These requirements were comparable with or higher than other polychaete species, highlighting the potential for fish waste bioremediation by Capitella sp. and O. craigsmithi. Preserved diets reduced bioremediation potential 1.5 and 3−5 times for, respectively, Capitella sp. and O. craig- smithi. Assuming that polychaetes are efficient fish-faeces convertors, the bioremediation poten- tial indicates that benthic cultivation units containing 65 000−95 000 ind. m−2 of Capitella sp. or 36 000−194 000 ind. m−2 of O. craigsmithi can convert the daily organic waste flux deposited below an average salmon farm. These densities were within ranges reported for wild populations, indi- cating that, based on the bioremediation potential, development of benthic IMTA with these 2 polychaete species seems realistic and efficient for waste conversion.
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