The SLRC – located at The Norwegian University of Life Sciences (NMBU) in Oslo, The Institute of Marine Research (IMR) and The University of Bergen (UIB) – is organised into six different work packages (WP) that each focus on different areas of salmon louse research to achieve a common goal- to generate knowledge about the salmon louse for future parasite control.

Single fish tank system

In order for the researchers at the SRLC to study the biology of the salmon louse they depend on access to live specimens of the louse. This is achieved by the Licelab (WP 6), a wet lab facility located at the UIB. Here, salmon louse are continuously cultivated on salmon in order to provide the other WPs with lice for their research. The LiceLab facility also facilitates studies of interactions between salmon louse and salmon (host) and functional studies of the lice. Another important part of the SLRC is the LiceBase (WP 5), a database where genomic information about the salmon louse are stored and shared among SLRC researchers. The database is an important tool as understanding the biology of the salmon louse requires access to its genetic information. The other WPs of the SLRC aims to gain knowledge about the biology of the salmon louse on a molecular level, how the louse interacts with and affects its host and also how the louse reacts to different medicines.

The aim of the SLRC is to be world leading on research on salmon louse and related parasites. By close collaboration between the different WPs and the industrial partners of the centre, short and long term solutions to control the salmon louse problem and to improve sustainability of the salmon farming industry, are made a reality.

From gene sequence to functional studies.

Knowledge about an organisms gene sequences is vital in order to perform basic biological research and understand an organism. The salmon louse genome has been fully sequenced and is available for the researchers at the SLRC in the LiceBase genome database. The genes, defined loci on the DNA encoding for functional proteins can be investigated and the gene sequence encoding a protein of interest can be found and the researchers can use it to among other things study the function of the gene.

LiceBase

One type of experiment scientists at the SLRC use in order to study the function of a gene is by knocking the gene down in a process called RNA interference (RNAi). RNAi is a natural biological process first discovered in the roundworm Caenorhabditis elegans, where specific types of RNA molecules inhibit gene expression by destruction of targeted mRNA.

In order to use RNAi as a method to study gene function in the salmon louse, a double stranded RNA (dsRNA) fragment that has the same sequence as the gene of interest, have to be made in the lab. The dsRNA fragment is a copy of a part of the gene the scientists are interested to study and it is made from DNA by a specific enzyme called RNA polymerase. When the dsRNA fragment enters the salmon louse, it is chopped-up by different enzymes into short and single stranded (ss) pieces of RNA. These pieces bind to the genes mRNA and destroys it so the mRNA cannot be translated into protein. The gene is then knocked down and the organism can get seriously affected and even die dependent of the importance of the gene.                                   

Injection of sea lice

The dsRNA fragment is injected into the salmon louse underneath its exoskeleton with a custom-made glass syringe. A colour is added to the dsRNA fragment to visualize the injection. Usually, pre-adult II female lice are injected with dsRNA fragment. By injecting pre-adult females, one can find out if the gene of interest are important both in general biological processes in the louse as well as in reproduction and generation of offspring.

In order to determine if the female lice is affected by the injected dsRNA, another group of lice are injected with a dsRNA fragment NOT targeted to any gene found in the salmon louse genome. These lice are called the control group.

Male sea lice and a female with eggstrings

After injection, the female lice is put on a salmon together with adult males and left on the salmon until the females are adults and produce egg strings. The salmon is kept in single fish tanks so that the lice injected with dsRNA targeted to the gene of interest are separated from the control group. After about one month the female lice have produced two sets of egg strings, and are together with the male lice, removed from the fish. The female lice are photographed and their “looks” or phenotype are investigated and compared to the control group.