Transferrin polymorphism of common carp. Link with disease resistance
Patrycja Jurecka is appointed as ‘sandwich’ PhD between the Cell Biology & Immunology (CBI) group of the Wageningen University and the Institute of Ichthyobiology & Aquaculture of the Polish Academy of Sciences (IIA-PAS). She started her research in 2001. The IIA-PAS holds a carp live gene bank that contains 19 breeding lines with considerable genetic variation in survival under pond conditions (9-68% survival at one year of age).
Common carp in Central Eastern Europe are cultivated in natural ponds on a semi-intensive scale and are vulnerable to diseases caused by a wide range of pathogenic organisms. The recognition of farming ponds as valued ecosystems argues against pharmacological interventions and strongly in favour of sustainable approaches, such as genetic selection for increased resistance to disease. This could be achieved by improving the immune capacity of carp by genetic selection. Genes of prime interest for marker studies are the transferrin (Tf) genes. Carp Tf protein polymorphisms exist in the carp live gene bank. We aim to identify the complete carp Tf cDNAs and describe the polymorphic sites. We hypothesize that selecting carp lines for particular Tf alleles allows for an increased survival rate.
Iron participates as a vital element in a wide variety of metabolic processes and the coordinate control of iron uptake and storage is tightly regulated. In plasma, iron is transported by Tf, a 80-kDa glycoprotein with two globular domains each with a high-affinity binding site for a single iron molecule. These binding sites are highly conserved through evolution. Pathogens use a variety of mechanisms to acquire iron. T. brucei for example, expresses host-specific Tf receptors. Tf may also modulate the immune response. Recently, in goldfish, it was shown that Tf cleavage products initiate the differentiation of monocytes into active macrophages.
- Differences in survival rate of carp grown in ponds (as established during the past 10 years) can be caused by many factors and not necessarily be caused by genetic differences in disease resistance. Can the differences in survival rate under pond conditions between a selection of 4 carp lines with a record of high survival and 4 lines showing low survival, be correlated with differences in resistance to Trypanoplasma borreli under laboratory circumstances?
- Can correlations be established between carp lines with a record of high or low survival (cq. high or low resistance to T. borreli) and immune polymorphisms for Tf?
- Can differences between carp lines in high or low survival rate/disease resistance unequivocally be correlated with the above-studied innate differences in immune responsiveness as detected in backcrosses?