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Browsing by Subject "geenitoiminta"

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  • Poikimista edeltävän ruokinnan vaikutus lypsylehmien rasvakudoksen energia-aineenvaihduntaan liittyvien geenien toimintaan 
    Vara, Katariina (2012)
    The main objective of this thesis was to analyse the impact of dry period energy intake on the intensity of metabolic stress and insulin resistance through changes in gene expression in dairy cows. Calving and beginning of lactation cause a negative energy balance which increases fat mobilization, metabolic stress and insulin resistance. These are intensified by high milk yield and excess energy intake from feed during the dry period. 14 genes were selected for the analysis. These genes encode proteins that are linked to lipogenesis, lipolysis and insulin signaling. The changes in the gene expression of subcutaneous adipose tissue were compared between two groups of eight cows. The control group was fed according to the energy requirements while the test group was fed ad libitum. The biopsies were taken -8d, +1d and +9d from parturition, cDNA was synthesized from them and they were analysed by quantitative PCR and 2-??CT-method. There Expression differences were observed in seven genes within the whole data between biopsy dates. During the period from before to after parturition, differences were identified in the expression of 11 genes within the whole data and the control group, and one gene in the test group. The most significant differences were observed in LEP and SCD genes. Between the groups there was a difference in the gene expression of IRS1 before parturition. This refers to the test group being more insulin resistant. After parturition there were no significant differences found in the gene expressions. The most significant changes observed in this study were as expected in early lactation. In the period between before and after parturition there were bigger changes in the gene expression observed in the control group than in the test group. The results indicate that cows getting more energy from their feed during the dry period are more insulin resistant before parturition.
  • Vitellogeniini ja sen sukulaisgeenit mehiläisellä 
    Stark, Taina (2015)
    The honey bee is ecologically important and nowadays, it is intensively studied species because of its decline worldwide. Vitellogenin (vg) is a pleiotropic gene that affects especially yolk formation but also e.g. longevity, immunity and labour division in honey bee. Recently, three vitellogenin-like genes have been found, but their functions are not yet discovered. They are named vitellogenin-like-A, vitellogenin-like-B and vitellogenin-like-C. Objectives of this MSc thesis were: i) Are vg and vg-like-genes expressed when the bee is exposed to oxidative stress, ii) Is Vg protein removed from the bee’s hemolymph after shielding her, and iii) Are vg-like-genes expressed abundantly in overwintering bees, like vg is. Oxidative stress was induced by injecting Paraquat. Sham injection was done with physiological saline. Control group had no injections. We found that inflammation by injection (both sham and Paraquat) had a surprisingly strong upregulating effect on vg and vg-like-A expression. Vg-like-B was only significantly upregulated by Paraquat, and vg-like-C had very low expression level with no treatment effect. When measuring Vg protein from fat body and hemolymph samples, no differences were found between treatments. Winter bees expressed high amounts of vg and vg-like-A. Taken together, it looks like vg-like-A works the same shielding way as vg, and vg-like-B slightly too, but vg-like-C might have specialized in other functions.

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