Validation of reference genes for quantitative RT-qPCR studies of gene expression in Atlantic cod (Gadus morhua l.) during temperature stress

<p>Abstract</p> <p>Background</p> <p>One important physiological response to environmental stress in animals is change in gene expression. To obtain reliable data from gene expression studies using RT-qPCR it is important to evaluate a set of possible reference genes as normalizers for expression. The expression of these candidate genes should be analyzed in the relevant tissues during normal and stressed situations. To find suitable reference genes it was crucial that the genes were stably expressed also during a situation of physiological stress. For poikilotermic animals like cod, changes in temperature are normal, but if the changes are faster than physiological compensation, the animals respond with typical stress responses. It has previously been shown that Atlantic cod show stress responses when elevation of water temperature is faster than 1 degree/day, for this reason we chose hyperthermia as stress agent for this experiment.</p> <p>Findings</p> <p>We here describe the expression of eight candidate reference genes from Atlantic cod (<it>Gadus morhua l</it>.) and their stability during thermal stress (temperature elevation of one degree C/day for 5 days). The genes investigated were: Eukaryotic elongation factor 1 alpha, <it>ef1a</it>; 18s ribosomal RNA; <it>18s</it>, Ubiquitin conjugate protein; <it>ubiq</it>, cytoskeletal beta-actin; <it>actb</it>, major histcompatibility complex I; MHC-I light chain, beta-2 -microglobulin; <it>b2m</it>, cytoskeletal alpha-tubulin; <it>tba1c</it>, acidic ribosomal phosphoprotein; <it>rplp1</it>, glucose-6-phosphate dehydrogenase; <it>g6pd</it>. Their expression were analyzed in 6 tissues (liver, head kidney, intestine, spleen, heart and gills) from cods exposed to elevated temperature and compared to a control group. Although there were variations between tissues with respect to reference gene stability, four transcripts were more consistent than the others: <it>ubiq</it>, <it>ef1a</it>, <it>18s </it>and <it>rplp1</it>. We therefore used these to analyze the expression of stress related genes (heat shock proteins) induced during hyperthermia. We found that both transcripts were significantly upregulated in several tissues in fish exposed to increased temperature.</p> <p>Conclusion</p> <p>This is the first study comparing reference genes for RT-qPCR analyses of expression during hyperthermia in Atlantic cod. <it>ef1a, 18s, rplp1 </it>and <it>ubiq </it>transcripts were found to be well suited as reference genes during these experimental conditions.</p

The ocean sampling day consortium

Ocean Sampling Day was initiated by the EU-funded Micro B3 (Marine Microbial Biodiversity, Bioinformatics, Biotechnology) project to obtain a snapshot of the marine microbial biodiversity and function of the world’s oceans. It is a simultaneous global mega-sequencing campaign aiming to generate the largest standardized microbial data set in a single day. This will be achievable only through the coordinated efforts of an Ocean Sampling Day Consortium, supportive partnerships and networks between sites. This commentary outlines the establishment, function and aims of the Consortium and describes our vision for a sustainable study of marine microbial communities and their embedded functional traits

The Ocean Sampling Day Consortium

Ocean Sampling Day was initiated by the EU-funded Micro B3 (Marine Microbial Biodiversity, Bioinformatics, Biotechnology) project to obtain a snapshot of the marine microbial biodiversity and function of the world’s oceans. It is a simultaneous global mega-sequencing campaign aiming to generate the largest standardized microbial data set in a single day. This will be achievable only through the coordinated efforts of an Ocean Sampling Day Consortium, supportive partnerships and networks between sites. This commentary outlines the establishment, function and aims of the Consortium and describes our vision for a sustainable study of marine microbial communities and their embedded functional traits

Gåseregistreringer i Vestfold; en vurdering av samlede bestander i fylket

Tombre, I. M., Andersen, G. E. B., Axelsen, T., Brandt, M., Hauge, F., Soglo, E., Syvert-sen, R., Karlsen, H. E., Kræmer, F., Lassen, M., Meyer, R., Moholt, Ø., Nilsen, R. N., Sondbø, S., Tjønnås, T. 2019. Gåseregistreringer i Vestfold; en vurdering av samlede be-stander i fylket. NINA rapport 1709. Norsk institutt for naturforskning. Denne rapporten presenterer resultater fra to koordinerte totaltellinger av gjess i Vestfold fylke sommeren 2019. Observatørene delte regionen i registreringssoner og gjennomførte systematiske tellinger av grågås (Anser anser) og hvitkinngås (Branta leucopsis). Det ble også registrert kanadagås (Branta canadensis) der denne ble sett. Grågås og hvitkinngås har økt i antall de siste tiårene, men samlede vurderinger i Norge er begrenset. Hvitkinngjessene i Vestfold anses å stamme fra den russiske bestanden som i løpet av de siste tiårene har etablert en egen hekkebestand både i indre og ytre Oslofjord. Grå- gjessene i Vestfold tilhører nordvest/sørvest bestanden som om vinteren trekker til det Europeiske kontinentet og mange helt til det sørlige Spania. For Vestfold ble det 28. juni 2019 registrert 3 632 grågjess og 553 hvitkinngjess. Den 8. august samme år var tilsvarende tall 5 288 grågjess og 795 hvitkinngjess. I noen tilfeller ble individene også aldersbestemt (voksenfugl (adulte) og ungfugler). Basert på disse registreringene anslås ungeproduksjonen/rekrutteringen å være et sted mellom 20 og 30 % i 2019. Arealbruk og fordeling av gjess var ikke fokus for registreringene i 2019, men gjessene ble registrert på alle typer habitater; fra holmer og skjær, til våtmarks- og friluftsområder og på dyrkede arealer (på grønnsakåkrer, høstede og uhøstede kornåkrer, o.a.)