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The importance of monitoring post-mortem game meat changes
Santajová, Markéta ; Bušová, Milena (advisor) ; Daniel, Daniel (referee)
The main aim of the thesis is to discover the significance of parameters of postmortal changes of game, on which we may well base for the further appraisal in practice.
The theoretical part describes company for processing game, from which the samples for the experiment were taken. Furthermore, it incorporates the composition and the qualities of meat and the factors that affect the meat of game. A significant chapter describes postmortal processes and ways of meat spoilage.
The experimental part of the thesis measures both the pH and ammoniac postmortal indicators. As for the experiment, the measurement was carried out on two groups of samples coming from the ham of wild boar.
With regard to the results the indicators were proved to be measurable postmortal parameters by postmortal changes and consequent process ripening of meat. The figures between individual measurements increased, but the dependence on time cannot be made on grounds of the results. The figure of ammoniac increased during the measurement too, and we gained a concrete image of its content in the meat thanks to photometric method. The results were compared with the measurement of ammoniac of slaughter animals. For analysis volume of ammoniac in specimen of lean flesh was used traditional micro method according to Conway.
More profound analysis ought to be made for the appraisal of postmortal indicators. Next interesting parametres for determination of significance postmortal changes could be also enzymatic substance.
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Intracellular distribution of hydrogen sulfide releasing enzymes in maturing porcine oocytes
Vondráková, Veronika ; Hošková, Kristýna (advisor) ; Tomáš, Tomáš (referee)
The study of the molecular mechanisms regulating reproductive processes is crucial for increasing the efficiency of reproductive biotechnologies that are often used in animal breeding. A key part of many biotechnological methods is the cultivation of oocytes, which simulates natural conditions in the ovaries. However this simulation is still imperfect and presents a limiting factor for successful formation of mammalian oocytes.capable of fertilization.
Meiotic maturation is influenced by many factors including for example gasotransmiter hydrogen sulfide (H2S). Until recently, hydrogen sulfide was known only as toxic gas polluting the environment. It was found that the hydrogen sulfide is at low concentrations important signaling molecule with a lot of physiological functions. Hydrogen sulfide is produced by enzymes CBS, CTH and 3-MPST in various tissues of the body, including the reproductive system.
We hypothesised that enzymes responsible for the endogenous production of hydrogen sulfide, CBS, CTH and 3-MPST, are present in porcine oocytes and their presence varies during meiotic maturation in cellular organelles. The goal of this study was to prove this hypothesis by cultivating porcine oocytes, detection of mitochondria, endoplasmic reticulum and hydrogen sulfide-releasing enzymes using imunocytochemistry and colocalization analysis.
Our results showed that enzymes releasing hydrogen sulfide, CBS, CTH and 3-MPST, are present in GV porcine oocytes and also in the oocytes matured to the MII stage, after 48 hours in vitro cultivation. We found that the distribution of these enzymes in cellular organelles in oocyte changed during meiotic maturation. There were significant changes in the distribution of enzymes 3-MPST and CBS in the mitochondria, levels of colocalization coefficients for enzyme 3-MPST increased, these coefficients for enzyme CBS decreased during meiotic maturation. In endoplasmic reticulum we found significant changes in the distribution of all three hydrogen sulfide-releasing enzymes. Levels of colocalitazion coefficients for CBS and 3-MPST increased, while levels of these coefficients for enzyme CTH decreased. Results of our experiments on porcine oocytes can help to clarify the role of gasotransmitter hydrogen sulfide during meiotic maturaion mammals of oocytes and are highly valueable because their possible application in breeding of farm animals and in human assisted reproduction.
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Molecular mechanism of hydrogen sulfide action during meiotic maturation of porcine oocytes
Veselá, Andrea ; Hošková, Kristýna (advisor) ; Tomáš, Tomáš (referee)
At present reproductive biotechnology methods are on the rise, but their development and application in the broader management of reproduction is dependent on obtaining a sufficient number of quality oocytes cultured in vitro. The prerequisite for this requirement is the creation of the optimal conditions in the course of culturing oocytes.
Understanding and knowledge of the processes that occur in oocyte during maturation is an important and necessary condition for optimizing the process of culturing oocytes in vitro and gaining a sufficient number of good quality oocytes in metaphase II of meiotic division. A large number of mechanisms that affect and control oocyte maturation are known, however it cannot be claimed that this process has been fully explained and studied. One factor which has a potential role in the regulation of meiotic maturation of oocytes is gasotransmitter hydrogen sulfide (H2S), a critical signaling molecule of endogenous origin.
The study of H2S led to the hypothesis that H2S actively influences the course of meiotic maturation of pig oocytes by regulating key signaling cascades. The aim of this work was to determine the involvement of H2S in the regulation of the MEK1-MAPK signaling cascade, responsible for the initiation and progress of the meiotic maturation of oocytes and the MEK1-PARP-1 cascade as signaling that supports cell viability. For this purpose, pig oocytes cultured in modified media were used, supplemented with a specific combination of enzyme inhibitors (3Ki) or in a culture medium with donor H2S. The ocytes were then subjected to immunocytochemistry staining, fluorescence microscopy and image analysis.
The results show that H2S is involved in the regulation of meiotic maturation. It confirmed the hypothesis of the endogenous production of H2S in the course of the meiotic maturation of pig oocytes and the influence of the MAPK signaling cascade. Based on the results, it is however likely that the MEK1-PARP-1 signaling cascade is not affected by H2S, unlike MAPK signaling, comprising the mentioned MEK1 as superior kinase. MAPK kinase activity is significantly lower in oocytes after treatment 3Ki. Further experiments are for a detailed understanding of these regulatory pathways and for the proper verification of the mechanism of the effects of H2S necessary, in particular for a full understanding of the target control factors by the post-translational modification of S-sulfhydration.
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Problems with sulphur and silicon in biogas
Holub, Radim ; Jecha, David (referee) ; Beňo, Zdeněk (advisor)
The main objective of this bachelor’s thesis is a description of a composition of biogas (BG) and contained undesirable components, which include especially sulphur and silicon compounds. In an introductory chapter is given a definition of the biogas, principle of its creation, chemical composition and a share of undesirable components. In following chapters are described single undesirable components, their properties and negative impact on parts of equipment using biogas. The following are the methods to reduce the critical concentration values of these components or their complete removal from biogas. In the thesis are also given practical solutions to eliminate these undesirable components.
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