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Karlsen, O.

Publications and source records attributed to Karlsen, O..

2 recordsLinked to original sources
bioRxiv2020

Untangling mechanisms of crude oil toxicity in a cold water fish via gene expression, morphology and PAHs at two developmental stages

Early life stages of fish are highly sensitive to crude oil exposure and thus, short term exposures during critical developmental periods could have detrimental consequences for juvenile survival. Here we administered crude oil to Atlantic haddock (Melanogrammus aeglefinus) in short term (3-day) exposures at two developmental time periods: before first heartbeat, from gastrulation to cardiac cone stage (early), and from first heartbeat to one day before hatching (late). A frequent sampling regime enabled us to determine immediate PAH uptake, metabolite formation and gene expression changes. In general, the embryotoxic consequences of an oil exposure were more severe in the early exposure animals. Oil droplet fouling in the highest doses resulted in severe cardiac and craniofacial abnormalities. Gene expression changes of Cytochrome 1 a,b,c and d (cyp1a,b,c,d), Bone morphogenetic protein 10 (bmp10), ABC transporter b1 (abcb1) and Rh-associated G-protein (rhag) were linked to PAH uptake, occurrence of metabolites of phenanthrene and developmental and functional abnormalities. We detected circulation-independent, oil-induced gene expression changes and separated phenotypes linked to proliferation, growth and disruption of formation events at early and late developmental stages. Our study gives an increased knowledge about developmentally dependent effects of crude oil toxicity. Thus, providing more knowledge and detail to new and several existing adverse outcome pathways of crude oil toxicity. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=93 SRC="FIGDIR/small/288852v2_ufig1.gif" ALT="Figure 1"> View larger version (35K): org.highwire.dtl.DTLVardef@106fe07org.highwire.dtl.DTLVardef@f8d7borg.highwire.dtl.DTLVardef@1118852org.highwire.dtl.DTLVardef@ccc59_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIOil droplet fouling occurred in the whole water column and increased the oil toxicity. C_LIO_LIEarly exposure resulted in higher PAH uptake due to lower metabolism resulting in more severe abnormalities. C_LIO_LIA rapid and circulation-indepenent regulation of bmp10 suggested a direct oil-induced effect on calcium homeostasis. C_LIO_LIExpression of rhag indicated a direct oil-induced effect on osmoregulatory cells and osmoregulation. C_LIO_LISevere eye abnormalities especially in the late exposure was linked to inappropriate overexpression of cyp1b in the eyes. C_LI

biochemistry↗
bioRxiv2020

RADSex: a computational workflow to study sex determination using Restriction Site-Associated DNA Sequencing data

The study of sex determination and sex chromosome organisation in non-model species has long been technically challenging, but new sequencing methodologies are now enabling precise and high-throughput identification of sex-specific genomic sequences. In particular, Restriction Site-Associated DNA Sequencing (RAD-Seq) is being extensively applied to explore sex determination systems in many plant and animal species. However, software designed to specifically search for sex-biased markers using RAD-Seq data is lacking. Here, we present RADSex, a computational analysis workflow designed to study the genetic basis of sex determination using RAD-Seq data. RADSex is simple to use, requires few computational resources, makes no prior assumptions about type of sex-determination system or structure of the sex locus, and offers convenient visualization through a dedicated R package. To demonstrate the functionality of RADSex, we re-analyzed a published dataset of Japanese medaka, Oryzias latipes, where we uncovered a previously unknown Y chromosome polymorphism. We then used RADSex to analyze new RAD-Seq datasets from 15 fish species spanning multiple systematic orders. We identified the sex determination system and sex-specific markers in six of these species, five of which had no known sex-markers prior to this study. We show that RADSex greatly facilitates the study of sex determination systems in non-model species and outperforms the commonly used RAD-Seq analysis software STACKS. RADSex in speed, resource usage, ease of application, and visualization options. Furthermore, our analysis of new datasets from 15 species provides new insights on sex determination in fish.

bioinformatics↗