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Origin, degeneration and detection of sex chromosomes
Jílková, Klára ; Král, Jiří (advisor) ; Kratochvíl, Lukáš (referee)
Sex chromosomes evolved from a pair of autosomes and they are differentiated as a result of supression of recombination. This process leads to a successive degradation of odd sex chromosome (alosome), which is becoming genetically inert finally or even excluded. Fundamental processes taking part in degeneration of alosome are Muller's ratchet, genetic hitchhiking, background selection, accumulation of transposable elements and constitutive heterochromatin. Indeed, these processes take part in either degeneration of both Y or W chromosomes. Remarkably, these alosomes show different rates of degeneration, most probably due to 1) different structure of male and female gonads as well as 2) different course of gametogenesis in both sexes. Furthermore, rate of alosome degeneration is usually lower in plants because they are haploid during the major part of life cycle. Other mechanisms of sex chromosome evolution involve rearrangements between autosomes and gonosomes, nondisjunctions and fissions of original sex chromosomes, transformation of B chromosomes into sex chromosomes or non-random segregation of autosomes with sex chromosomes. Other phenomenon that appears in sex chromosome evolution is transition between XY/XX and ZW/ZZ systems or transition between chromosomal sex determination and epigamy. Actually,...
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The impact of Fam84b in retinal homeostasis
Raishbrook, Miles Joseph ; Procházka, Jan (advisor) ; Mašek, Jan (referee)
Fam84b is a largely unstudied protein, where its function in eukaryotic cells is unclear. This thesis work presents a FAM84B knockout mouse model and characterises the resulting retinal phenotype in detail. FAM84B KO mice were morphologically assessed by optical coherence tomography and histological processing, revealing dynamic changes stemming from the photoreceptor and pigmented epithelial layers. This potent phenotype progresses with age, spreading inwards towards the inner retinal layers, as well as laterally to adjacent retinal regions. Comparative localisation of standard retinal cell markers demonstrates that FAM84B KO retinal layering becomes increasingly disorganised, together with deformation of the retinal macrostructure. Due to this, KO mice experience reducing responses to light, as demonstrated by electroretinography, where overall retinal efficiency falls. Fam84b shows homology to the HRASLS enzyme family, which are capable of attenuating Ras-associated signalling. To investigate whether Fam84b possesses a similar function, the level of phosphorylated and activated downstream Ras effectors were compared between wild type and FAM84B KO mouse retinal lysates. A reduction of pERK1 (pY204) in KO lysates suggests that Fam84b holds some function related to this pathway downstream of Ras....
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Origin, degeneration and detection of sex chromosomes
Jílková, Klára ; Král, Jiří (advisor) ; Kratochvíl, Lukáš (referee)
Sex chromosomes evolved from a pair of autosomes and they are differentiated as a result of supression of recombination. This process leads to a successive degradation of odd sex chromosome (alosome), which is becoming genetically inert finally or even excluded. Fundamental processes taking part in degeneration of alosome are Muller's ratchet, genetic hitchhiking, background selection, accumulation of transposable elements and constitutive heterochromatin. Indeed, these processes take part in either degeneration of both Y or W chromosomes. Remarkably, these alosomes show different rates of degeneration, most probably due to 1) different structure of male and female gonads as well as 2) different course of gametogenesis in both sexes. Furthermore, rate of alosome degeneration is usually lower in plants because they are haploid during the major part of life cycle. Other mechanisms of sex chromosome evolution involve rearrangements between autosomes and gonosomes, nondisjunctions and fissions of original sex chromosomes, transformation of B chromosomes into sex chromosomes or non-random segregation of autosomes with sex chromosomes. Other phenomenon that appears in sex chromosome evolution is transition between XY/XX and ZW/ZZ systems or transition between chromosomal sex determination and epigamy. Actually,...
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Eugenics in the Czech Countries in the First Half of the 20th Century
MEZEROVÁ, Kristýna
The thesis defines Czech eugenics in the 1. half of the 20. of the century. For understanding Czech eugenics, I outlined the development eugenics from its beginnings. The work presents main themes czech eugenics, for example degeneration of the human race, ways for its regeneration, establishment of eugenic marital revision or the importace of medical examinations before marriage. The thesis also presents most famous Czech eugenics. The thesis focuses on the German racial, its main Themis such as sterilization and euthanasia. The thesis compares the Czech eugenics and other similar movements. It is a theoretical work, the research here is applied primarily to the historical method, in particular, the analysis of the literary sources, which are primarily works of Czech, published in the 1. half of the 20. of the century. Also uses the comparative method when comparing the eugenics of the Czech and other similar movements. In the work are used in particular in Czech, but also an literary sources. The work attempts to answer the following research questions: 1. How was the Czech the eugenic movement and who led him? 2. What were the main themes of the Czech eugenic movement? 3. What were the similarities, or of the cooperation of the Czech movement with foreign eugenics associations? She worked on the Czech eugenic movement German racial hygiene? 4. That circumstances contributed to the demise of the Czech eugennic movement?
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Vliv teploty při krátkodobém uchování jiker jesetera malého, Acipenser ruthenus, in vitro
LET, Marek
The effects of temperature (7°C, 11°C, 15°C, and 19°C) and egg storage time (Control = time 0 h, 2.5 h, 5.0 h, 7.5 h and 10.0 h) on the fertilization and hatching success of sterlet, Acipenser ruthenus, eggs were studied. Ovulation and spermiation were stimulated by using CPE in two dosages for females (first dose 0.5 mg.kg-1 b.w. and second dose 4.0 mg.kg-1 b.w.) and one dosage for males (4.0 mg.kg-1 b.w.), respectivelly. The ovulated eggs were collected from three females (age 68 years) through a small surgery, than mixed together. The good quality semen was selected from three males (age 68 years) and was stored in polystyrene ice box during the experiment. The eggs were placed separately into four incubators, where were stored in above-mentioned temperature conditions. Four grams of eggs from each temperature treatment groups were inseminated with 200 ?l of the semen in dechlorinated water at 15°C. Then, eggs were placed into experimental cage incubation system with separate chambers at 15°C and a small sample of fertilized eggs was allocated in triplicate to plastic petri dishes for evaluation of fertilization rate during neuralization phase. Approximately, 56 days post-fertilization, the total number of succesfully hatched larvae was acurately calculated for the final evaluation of storage success. All data were analyzed using STATISTICA v 12 software. Hatching success was analyzed using a factorial ANOVA model containing the egg storage time and storage temperatures. Eggs retained their hatchability when stored at 7°C and 11°C for up to 10 hours. Egg viability was noticeably reduced at 7.5-h storage at 19°C compared to cooler temperatures, moreover the viability decreased significantly after 10 hours at 19°C. In contrast with the one previous study about shor-term storage of sterlet eggs, this experiment probably dealt with better quality eggs which can be a reason why they retained their hatchability for significantly longer time period.
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