Biology subjects

Vik, J. O.

Publications and source records attributed to Vik, J. O..

4 recordsLinked to original sources

bioRxiv2017

Transcriptional development of phospholipid and lipoprotein metabolism in different intestinal regions of Atlantic salmon (Salmo salar) fry

BackgroundIt has been suggested that the high phospholipid (PL) requirement in Atlantic salmon (Salmo salar) fry is due to insufficient intestinal de-novo synthesis causing low lipoprotein (LP) production and reduced transport capacity of dietary lipids. However, there has not been performed any in-depth ontological analysis of intestinal PL and LP synthesis with development of salmon. Therefore in this paper we used RNA-seq technology to test the hypothesis that the high PL requirement in salmon fry was associated with undeveloped PL synthesis and LP formation pathways in intestine. There was a special focus on the understanding homologous genes, especially from salmonid-specific fourth vertebrate whole-genome duplication (Ss4R), contribution to salmonid specific features of regulation of PL metabolic pathways. The study was performed in stomach, pyloric caeca and hindgut at 0.16g (1 day before first-feeding), 2.5g and 10g of salmon.\n\nResultsIn general, we found an up-regulation of de-novo phosphatidylcholine (PtdCho) synthesis, phosphatidylethanolamine (PtdEtn) and LP formation pathways in pyloric caeca of salmon between 0.16g and 10g. Thirteen genes in these pathways were highly (q<0.05) up-regulated in 2.5g salmon compared to 0.16g, while only five more significant (q<0.05) genes were found when the fish grew up to 10g. Different homologous genes were found dominating in stomach, pyloric caeca and hindgut. However, the expression of dominating genes in PL and LP synthesis pathways was much higher in pyloric caeca than stomach and hindgut. Salmon-specific homologous (Ss4R) genes had similar expression during development, while other homologs had more diverged expression.\n\nConclusionsAn increasing capacity for PL synthesis and LP formation was confirmed in pyloric caeca. The up-regulation of the de-novo PtdCho pathway confirms that the salmon fry have increasing requirement for dietary PtdCho compared to adult. The similar expressions between Ss4R homologous genes suggest that the functional divergence of these genes was incomplete compared to homologs derived from other whole genome duplication. The results of the present study have provided new information on the molecular mechanisms of phospholipid synthesis and lipoprotein formation in fish.

molecular biology↗

bioRxiv2017

Interoperable genome annotation with GBOL, an extendable infrastructure for functional data mining

BackgroundA standard structured format is used by the public sequence databases to present genome annotations. A prerequisite for a direct functional comparison is consistent annotation of the genetic elements with evidence statements. However, the current format provides limited support for data mining, hampering comparative analyses at large scale.\n\nResultsThe provenance of a genome annotation describes the contextual details and derivation history of the process that resulted in the annotation. To enable interoperability of genome annotations, we have developed the Genome Biology Ontology Language (GBOL) and associated infrastructure (GBOL stack). GBOL is provenance aware and thus provides a consistent representation of functional genome annotations linked to the provenance. GBOL is modular in design, extendible and linked to existing ontologies. The GBOL stack of supporting tools enforces consistency within and between the GBOL definitions in the ontology (OWL) and the Shape Expressions (ShEx) language describing the graph structure. Modules have been developed to serialize the linked data (RDF) and to generate a plain text format files.\n\nConclusionThe main rationale for applying formalized information models is to improve the exchange of information. GBOL uses and extends current ontologies to provide a formal representation of genomic entities, along with their properties and relations. The deliberate integration of data provenance in the ontology enables review of automatically obtained genome annotations at a large scale. The GBOL stack facilitates consistent usage of the ontology.

genomics↗

bioRxiv2017

Diet And Life Stage Associated Remodeling Of Lipid Metabolism Regulation In The Duplicated Atlantic Salmon Genome

Atlantic salmon migrates from rivers to sea to feed, grow and develop gonads before returning to spawn in freshwater. These habitat shifts require great phenotypic plasticity. To address the unresolved question of how the shift in diet between fresh and saltwater affects the regulation of metabolic function, we fed salmon contrasting diets in each of the two life stages. Combining transcriptomics with comparative genomics, we found that lipid metabolism undergoes a concerted shift between fresh- and saltwater stages. Lipogenesis and lipid transport become less active in liver after transition to saltwater, while genes for lipid uptake in gut are more expressed in lipid-rich seawater environments. We assess how the whole-genome duplication that gave rise to the salmonids has impacted the evolution of lipid metabolism, and find signatures of pathway-specific selection pressure on gene duplicates, as well as a limited number of cases of increased gene dosage.

evolutionary biology↗

bioRxiv2016

Functional Analysis of All Salmonid Genomes (FAASG): an international initiative supporting future salmonid research, conservation and aquaculture

We describe an emerging initiative - the Functional Analysis of All Salmonid Genomes (FAASG), which will leverage the extensive trait diversity that has evolved since a whole genome duplication event in the salmonid ancestor, to develop an integrative understanding of the functional genomic basis of phenotypic variation. The outcomes of FAASG will have diverse applications, ranging from improved understanding of genome evolution, through to improving the efficiency and sustainability of aquaculture production, supporting the future of fundamental and applied research in an iconic fish lineage of major societal importance.

genomics↗