Unveiling secrets of anoxia tolerance in bearded goby

Bearded gobies from the Benguela system off Namibia are remarkable for their tolerance of low-oxygen conditions. Anne Gro Vea Salvanes from EvoFish has supervised a number of master projects to better understand the biology of this fascinating fish species. In his thesis, Moritz Pohl is taking these investigations to molecular level, in a project that is jointly supervised with Anders Goksøyr and Roger Lille-Langøy from the Environmental Toxicology group. Here Moritz himselves describes the project:

After life first appeared under anoxia, the rise in atmospheric oxygen level is regarded as the trigger of appearance of eukaryotes and still has it´s impact on evolution and diversity of vertebrates. Once the adaption was directed towards dealing with higher concentrations of oxygen, todays´ challenge depicts to deal with limiting concentrations when hypoxia newly originates. The predominant principle of metabolic energy gain has evolved to be aerobic respiration. Therefore changes in oxygen availability can affect the complete composition of an ecosystem and lead to dramatic impacts on all represented taxa and the complete foodweb. This has recently been shown for the Benguela upwelling ecosystem.

Here the Bearded goby (Sufflogobius bibarbatus) shows an unprecedented successful adaption resulting in an increase in population size.

As a student from Germany in the final term of my biology master program I decided to take the opportunity of researching in Norway when the chance arose. I started to work with S. bibarbatus samples taken in 2011/2012 in front of the Namibian coast. In this six-month masterthesis-project we began to look at the genetic disposition of the gobies by molecular approach. The objective was to obtain the unknown DNA sequence of the Hypoxia-inducible factor 1 (HIF-1a). The HIF-1a protein is a highly conserved oxygen sensing system that is acting as a transcription factor and induces a huge variety of target genes. This regulates the metabolic response to hypoxia. Reference genes with stable expression levels are used as internal stadards. Once the DNA sequences are elicited and validated, gene-specific oligonucleotide primer are designed for real-time polymerase chain reaction (qPCR). This technique allows  detection of the amount of transcribed HIF. The quantification would enable comparison between populations of gobies catched at hypoxic and normoxic sites. Differences in HIF expression can be linked to oxygen level, tissue, daytime and every evaluated parameter. This will give a better understanding of the ability of Sufflogobius bibarbatus to benefit from the usually disadvantageous factor hypoxia.