Aquaculture for all
The Fish Site presents: The Vienna Sessions - Conversations about aquaculture. 9 video interviews with aquaculture thought leaders. Watch here.

Using Cells to Model Fish Nutrition and Development

SWEDEN - Cultures of stem cells and other cells are useful tools for studying the impacts of environmental pollutants and nutrients on fish health and development.

Capture: The picture shows liver cells 18 hours after being isolated from Atlantic salmon.
Photo: NIFES

Researchers from NIFES will present results related to this topic at the fifteenth ESTIV 2008 conference in Stockholm, Sweden, the 25th of September.

The conference is for scientists from all over the world who study the biological effects of environmental pollutants.

The National Institute of Nutrition and Seafood Research (NIFES) in Bergen, Norway, will present work carried out in two cell models at the conference; one cell model based on liver cells from Atlantic salmon, and one model based on embryonic stem cells from Atlantic cod. Studying cells exposed to nutrients and toxic substances enable researchers to evaluate the effect of environmental pollutants and nutrients on fish embryos and adult fish. The results are from the project "Integrating in vitro cellular models and Genomic techniques for investigating the impacts of diets" supported by the Norwegian Research Council. This is a 4 year project, which will end in 2010.

Cells from salmon are affected by the environmental pollutant PFOS

It is common to use liver cells as a model system due to the liver´s high metabolic activity and that it is the major detoxifying organ in the body. In this study, liver cells from Atlantic salmon were exposed to the perfluorinated compound, PFOS. PFOS is commonly used in materials which are water repellent, and the compounds accumulate both in the environment and in organisms ranging from algae to humans. Anne Krøvel will present results which show that genes known to respond to PFOS in other species are also responding in Atlantic salmon liver cells.

Improved risk assessment

In an experiment done by Liv Søfteland and Pål Olsvik, liver cells from Atlantic salmon was exposed to a mixture of different persistent organic pollutants. This cell model can help us understand how several environmental pollutants combined affect the cells. Several gene markers were used in order to examine how cells are affected by the mix of environmental pollutants.

"The model can for example show whether the presence of two different environmental pollutants have a greater toxic effect in combination than on their own," says Søfteland.

New method developed to grow embryonic stem cells

Capture: The picture shows fertilized fish eggs, containing embryonic stem cells in the blastula stage (less than 1000 cells). The eggs are about 1mm in diameter.
Photo: NIFES

Elisabeth Holen and Kaja Skjærven will present a new method developed to grow embryonic stem cells. Stem cells are unspecialised cells which can divide many times, and give rise to specialised cells through differentiation. Embryonic stem cells are present in the embryo until it reaches a specific stage of development. These cells also have the unique property of being able to develop into any cell, such as for example muscle cells or nerve cells.

"Research at NIFES shows that the gene ac-pou2 is a marker for embryonic stem cells in Atlantic cod. When the stem cells start to differentiate, the gene ac-pou2 is "turned off"," says Holen.

The gene marker ac-pou2 is only tuned on during the developmental stage called the blastula stage, which is the two first days after fertilization at 6oC. The marker is isolated and cloned at NIFES.

New method to determine eicosanoids in cell cultures

Pedro Araujo has developed a new method for determining eicosanoids (such as prostaglandin E2 (PGE2)) from liver cells isolated from rat and head kidney cells isolated from Atlantic salmon and Atlantic cod. Eicosanoids are local hormones which are involved in inflammatory reactions in mammals.

"The cell culture model might be a suitable substitute for animal experiments, where exposure to a toxic compound and the subsequent inflammatory reaction is measured," says Araujo.

The determination is done by using direct injection of the redissolved cell culture sample into a single liquid chromatography column coupled to mass spectrometry (LCMS).

"To our knowledge," says Araujo, "this is the first time that direct injection of redissolved cell cultures has been applied to study eicosanoids in cell cultures by LCMS. The proposed method is an effective, simple and rapid strategy for the analysis of PGE2 in cell cultures and the method has potential for broad implementation in monitoring biomarkers in cell cultures".

Araujo will present the results at the international conference Biomarker Discovery Europe 2008 in Dublin, Ireland the 2nd – 3rd October.