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Iniciace pohybu byčíku, signalizace a regulace pohyblivosti spermií ryb: fyzikální a biochemické řízení
PROKOPCHUK, Galina
The current study attempted to shed light on the regulatory processes and response arrangements of fish spermatozoa during the course of maturation and motility initiation. The first intent of this study was to improve the understanding of the mechanism underlying the acquisition of potential for sperm motility in sturgeon. Up to present work, the physiological process underlying sperm maturation in this species has not been described at all. Our results showed that sperm maturation in sturgeon occurs outside the testes because of dilution of sperm by urine and involves the participation of high molecular weight substances as well as calcium ions present in seminal fluid and/or urine. The second aim of the present study was to investigate the coping mechanisms in fish spermatozoa with osmotic and ionic activating mode, as well as in spermatozoa of euryhaline fishes, to various environmental conditions. We showed that alteration of environmental osmolality might affect the fish sperm in different ways, depending on fish species and modes of spermatozoa motility activation either osmotic or ionic mode. In response to osmotic stress caused by hypotonicity, carp spermatozoa regulated the flow of water across their cell membrane and increased their cytoplasmic volume during their short motility period. In contrast, no indications of sperm volume changes were observed neither in sterlet nor in brook trout spermatozoa, both of which having an ionic mode of motility activation. We also examined the mechanism by which sperm motility triggering in euryhaline fishes can adapt to a broad range of environmental salinity. Our results demonstrated that spermatozoa of euryhaline tilapia, Sarotherodon melanotheron heudelotii, reared in fresh-, sea- or hypersaline water can be activated in hypotonic, isotonic or hypertonic conditions of swimming milieu, provided Ca2+ ions are present at various levels. It was established that the higher the fish rearing salinity or the more hypertonic ambient media at spermatozoa activation, the higher extracellular concentration of Ca2+ ions is required. The results obtained in the present study allow suggesting that osmolality is not the main factor inhibiting sperm motility inside the testis in the S. melanotheron heudelotii. A third aim of this study was investigation of the regulation of motility initiation process and description of flagellar beating initiation in chondrostean spermatozoa. We detected that K+ inhibition of sperm motility in sturgeon can be by-passed due to the pre-exposure of sperm cells to a high osmolality shock prior to its transfer to K+-rich swimming media. Thus, we hypothesized that sturgeon spermatozoa may be activated by use of an unexpected signaling pathway, independent from regular ionic stimulation. The successive activation steps in sturgeon spermatozoa were investigated by high-speed video microscopy, using specific experimental situation, where sperm motility initiation was delayed in time up to several seconds. At motility initiation, the first couple of bends formed at the basal region begins to propagate towards the flagellar tip, but gradually fades when reaching the mid-flagellum. This behavior repeats several times until a stage where the amplitudes of bends gradually reach similar value, what eventually leads to sperm progressive displacement. The total period needed for the flagellum to switch from immobility with rigid shape to full activity with regular propagating bends ranges from 0.4 to 1.2 seconds. In conclusion, the results of the current study bring valuable pieces of information into the general understanding of the processes of maturation of fish spermatozoa, their adaptability to different physical and biochemical circumstances, the extra- and intra-cellular signaling as well as the regulatory mechanisms of motility activation in fish spermatozoa.
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Computational modelling of strain and stress in spur gearing using FEM
Ševčík, Martin ; Maňas, Pavel (referee) ; Vrbka, Martin (advisor)
This diploma thesis deals with computation modeling of spur gearing using FEM. The methodology of checking calculation was suggested for gears which are not possible to check only by using standard ČSN 01 4686. The analysis of influence of vicinity of stress concentration on stress distribution in tooth root was performed. It is possibility to use the gears with thinner rim than the standard ČSN 01 4686 recommends. The main part of this work is devoted to fatigue crack propagation study in gears with thin rim. Aiding T-stress the influence of constraint and stress multiaxiality on crack propagation was taking into account. The predicted fatigue crack propagation paths were compared with certain experimental data. It is demonstrated that the considering of influence of constraint improves estimation of consequent crack propagation direction and in some cases the influence of constraint can significantly change the estimated crack propagation path.
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Compensatory exercising by Lumbosacralis syndrome
Telenská, Lucie ; Malá, Michaela (referee) ; Hošková, Blanka (advisor)
Title of the project: Compensatory exercising by Lumbosacralis syndrome Purphose of the project: Main load of the graduation theses is analysis and documentation of effects functional breathing exercises and balance compenzation by fit-ball by the help of logging dates from each informant, by physical metering (posture, checkup dynamic of spina column, muscular testing) and by mental characteristic (questinnaire about modification ofpain). Methodology: Used methods result from principle quantitative experimentation. Research was intent on obtaining objektive proofs by means of input and output investigation and questionnaire. Constitute experimentation was interfacing functional breathing exercises and balance compenzation with fit-ball. Finally interpratation and confrontation ofobtained dates. Findings: It has benn confirmed, that the application of functional breathing exercises and balance compenzation make for pains palliation and palliation of muscles disbalance in part of lumbar spine by monitored subjects. These changes went to a better feeling fitness and positively demonstrated in activities ofdaily living. Key words: Lumbosacralis syndrome, functional breathing exercises, balance compenzation by fit-ball.
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Production of secondary metabolites in plant tissue cultures
Provazníková, Věra ; Siatka, Tomáš (advisor) ; Kašparová, Marie (referee)
Věra Provazníková Production of secondary metabolites in plant tissue cultures Experimental work aimed at monitoring of influence of the cerium chlorid as an elicitor on the production of scopoletin in Angelica archangelica L suspension cultures. Cultivation was carried out by on Murashige and Skoog medium in the light and also in the darkness. For the quantification of scopoletin was used technique of high performance chromatography with fluorimetric detection. The findings of the work demonstrated the higher values of the scopoletin amount by the cerium iones elicitation at the cultivation in the dark.
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Vliv polynenasycených mastných kyselin na zastoupení mastných kyselin ve tkáních a hladinu cholesterolu u potkanů
Kácalová, Tereza
The aim of this work was demonstrate positive effect of n-3 polyunsaturated fatty acids EPA and DHA on the concentration of plasma triglycerides and cholesterol. According to the hypothesis, these polyunsaturated fatty acids are capable of reducing plasma cho-lesterol in mechanism, where is increased gene expression Insig-1 and simultaneously reduces the expression of genes encoding an enzyme for cholesterol synthesis (3-hydroxy-3-methylglutaryl-CoA reductase, a gene for HMG-CoA-R) and the gene for the LDL receptor, which is responsible for the entry of cholesterol from the plasma into the cells (low density lipoprotein receptor, the density, the LDL-R gene). LDL-R.The experiment was conducted on a model animal (Rattus norvegicus) fed with a standard feed mixture with the addition of 3% of salmon oil, fish oil 6% and 6% of oil from algae of the genus Schizochytrium. The control group was fed a feed mixture with the addition of 6% safflower oil, food with the addition of 3% palm oil was used as a negative control. Each group consisted of 10 animals. From the blood samples was determined levels of total cholesterol, HDL-cholesterol, LDL-cholesterol and triglycerides. The fatty acid content was determined in muscle, liver and adipose tissue. Food enriched with eicosapentaenoic acid and docosahexaenoic acid led to a reduction in total cholesterol and LDL-cholesterol levels. It was shown (P <0.05) after the addition of fish oil, salmon oil and algae of the genus Schizochytrium oil to feed mixtures of experimental rats, a decrease in total cholesterol (27%, 21%, 27% respectively) relative to controls. Our attempt partially confirmed the hypothesis. At the same time, we found that plasma lipid metabolism affects different mechanism than we thought.
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Modulace exprese alfa-synukleinu pomocí působení 5-S-cysteinyldopaminu na buňky lidského neuroblastonu SH-SY5Y: možná úloha katecholthioetherů při neurodegeneraci
Hrabáková, Rita ; Štaud, František (advisor) ; Mladěnka, Přemysl (referee)
-Synuclein is a presynaptic protein which has been demonstrated to be involved in PD etiopathogenesis.It can regulate DA homeostasis by inhibition of TH activity, by regulation of the DAT activity and finally by potential role in vesicular storage. - Synuclein is a natively unfolded protein, which can undergo overexpression and aggregation due to toxic insults or oxidative stress. The aggregation of α-synuclein leads to a loss of function, which in PD neurons may determine a dysregulation of the DA pathways with subsequent excess of cytosolic DA, that can enhance the neurotoxic effect of α-synuclein aggregates. In recent years, a catecholthioether metabolite of DA, 5-S-cysteinyl-dopamine, has been identified in certain dopaminergic regions of the brain, notably the Substantia nigra. Cys-DA seems to have a possible significance as an index of oxidative stress in aging and in neurodegenerative processes and it was recently hypothesized that this substance or its metabolites may be the endogenous neurotoxins responsible for neurodegeneration in PD. Hence, the aim of this experimental work was to determine whether Cys-DA is able to cause overexpression of -synuclein both at transcriptional and translational levels in a cellular model of PD, the human neuroblastoma dopaminergic cell line SH-SY5Y....
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Nanopositioning with detection of a standing wave
Holá, Miroslava ; Hrabina, Jan ; Číp, Ondřej ; Fejfar, A. ; Stuchlík, J. ; Kočka, J. ; Oulehla, Jindřich ; Lazar, Josef
A measuring technique is intended for displacement and position sensing over a limited range with detection of standing-wave pattern inside of a passive Fabry-Perot cavity. In this concept we consider locking of the laser optical frequency and the length of the Fabry-Perot cavity in resonance. Fixing the length of the cavity to e.g. a highly stable mechanical reference allows stabilizing wavelength of the laser in air and thus to eliminate especially the faster fluctuations of refractive index of air due to air flow and inhomogeneity. Detection of the interference maxima and minima within the Fabry-Perot cavity along the beam axis has been tested and proven with a low loss transparent photodetector with very low reflectivity. The transparent photodetector is based on a thin polycrystalline silicon layer. Reduction of losses was achieved thanks to a design as an optimized set of interference layers acting as an antireflection coating. The principle is demonstrated on an experimental setup.
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Growing Douglas-Fir in the area SLP CZU in Kostelec nad Cernymi lesy
Kubeček, Jiří ; Podrázský, Vilém (advisor) ; Marušák, Róbert (referee)
Douglas-fir (Pseudotsuga menziesii /Mirb./ Franco) is currently considered one of the most important introduced tree species in Europe; for example in Germany it is considered domesticated. By its production it surpasses significantly our domestic softwood and its importance is found both in amelioration and improving functions as well as in its ability to compensate for spruce, so far our most common species however retreating somewhere.
The work addresses the growth processes of individuals and stands of Douglas- fir and its selected environmental effects in regions of Kostelec nad Černými lesy, and Písek. The aim is to demonstrate the production potential, economic evaluation, describe the growth dynamics and the impact on soil quality in the stands. The methods applied will include dendrometric measurement, description of growth dynamics, profitability, sampling and analysis of humus and mineral soil horizons. Basic pedochemical characteristics will be analyzed: soil reaction, soil sorption complex, nutrient content in total and exchangeable forms. The results indicated a high produce ability of Douglas fir comparable to the one of Grand fir and exceeding the one of Norway spruce. In terms of stabilization and effects on soil also has better properties than spruce. In terms of amelioration resemble the qualities of deciduous trees.
The work follows on previous experimental investigation..The output provides quantification of the production and soilforming potential, yield assessment and recommendations for application in conditions of the University Forest Enterprise and the Czech Republic.
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