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Role of tetraspanin network during sperm-egg interaction and fusion
Černá, Pavlína ; Hortová, Kateřina (advisor) ; Petelák, Aleš (referee)
Fusion of sperm and egg is a crucial moment of the fertilization process which is fundamentally urged by tetraspanin superfamily proteins whose interactions allow mutual interaction of gamets and their subsequent fusion. Tetraspanins are 25-50 kD transmembrane proteins whose various kinds are found in most mammalian cells. Four transmembrane domains containing key amino acid residues indicating their function are their specificity. The essential feature of tetraspanins is their ability to form membranes lateral bonds which are reached thanks to large complexes with other proteins that form the so-called tetraspanin network. The interaction with other proteins and tetraspanins is important for a cell adhesion to the extracellular matrix, adhesion to the other cells, and it plays a role in signal transduction. This bachelor thesis describes and summarizes the role of tetraspanin networks during fusion of egg and sperm. A general introduction of tetraspanins, their structure and functions in cellular processes and interactions leading to the formation of tetraspanin networks which are the key point in fertilization, are given. A description of the fertilization process itself, the protein interactions and changes which precede it in included. The latest findings of the topic from the viewpoint of...
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Factors affecting deposition of selected antimicrobial substances into the egg structures
Pokorná, Monika ; Javůrková, Veronika (advisor) ; Svobodová, Jana (referee)
Both during the ovogenesis and immediately after the laying is a bird egg exposed to strong pressure from the microorganisms which are able to penetrate the egg through eggshell pores and infect its inner structures. With regard to the proved negative effects on hatchability, viability and phenotype of offspring, a cascade of obstacles has evolved which are able to minimize the risk of bacterial infection. The deposition of antimicrobial components into the eggshell and the egg white is considered to be one of them. A whole group of egg white proteins belong to them, among which lysozyme and ovotransferrin, which are also partially deposited into the eggshell and cuticular layer of the eggshell, dominate with their antimicrobial effect. The implication of the newest studies is that the microbial protection of the egg can be also performed by the eggshell pigments - biliverdin and protoporphyrin, which protect the egg from being colonized by microorganisms with an increased UV light and regulation of conductivity and water vapour condensation on the egg surface. Even though the presence of these antimicrobial components in different structures of the egg has been proved, there is no known comparative study which addresses the relation between deposition of selected antimicrobial components into...
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Study of the reproductive biology of the crayfish - mating, laying eggs and morphological structure of the male and female gametes
KUBEC, Jan
In the nature, crayfish are represented like predators or a part of food base of some fish. Also in free waters they acts as detrivors and are an important element in the nutrient and energy circle in aquatic ecosystem. The crayfish weren't able to avoid negative impacts of anthropogenic activities such as water pollution and devastation of habitats. For these reasons reproduction of the crayfish is necessary in hatcheries and farms. The main aim of my work was to study the reproductive biology of the crayfish focused on the process of mating, the interval between mating and laying eggs, fertilization and morphological structure of the male and female gametes. Among the secondary objectives there was included using of repeated electrostimulation of the crayfish and the possibility of hybrids of the noble crayfish (Astacus astacus) and the narrow-clawed crayfish (Astacus leptodactylus). The observation of the period of reproduction was realized on representativies of the noble crayfish and the narrow-clawed crayfish throughout natural mating in the tanks. The structure of gametes was observed on the samples taken from thenoble crayfish (Astacus astacus), the narrow-clawed crayfish (Astacus leptodactylus), the signal crayfish (Pacifastacus leniusculus), the red swamp crayfish (Procambarus clarkii) and spinycheek crayfish (Orconectes limosus). The experiments were carried out during the autumn season in 2012 and 2013. The results of observations of the reproduction of crayfish made us clear as for the period and intervals for all phases of the process of mating crayfish. For females the noble crayfish and the narrow-clawed crayfish was found oviposition without the presence of males. Their individual components have been described by using ultrastructure of males and female gametes. Repeated electrostimulation showed at the family Astacidae as a suitable tool for collecting large mass of sperm material. Hybridization experiment proved that it can occur to mate the two species of crayfish in areas where they occur simultaneously. These experiments helped to further knowledge of reproductive biology of crayfish.
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The adjustment of the feed ration for laying hens in order to improve the strength and the hardness of eggshells
HEINDL, Jakub
This major thesis expands the issue of the bachelor thesis "The issue of raising laying hens considering on introduction of enriched cages" and adds new knowledge relating to the topic feed rations and their influence on the final production. The theoretical part of the thesis analyses the basic theoretical concepts cohering with this topic, focused on creating a comprehensive overview of the structure and quality of the eggs, the basic ingredients in the feed rations, qualitative parameters of grapes as the modified additive provided by us and last but not least there is processed the recent overview of the current state of large-scale farmers in the Czech republic. The practical part of the thesis aims to test the effect of the proposed feed with an additive in the form of the crushed grape seeds, on the strength of the eggshell, by homogeneous samples of the breeds through from us proposed measuring instrument. Subsequently, a statistical evaluation of measured results is realized. In conclusion, the consideration is extended to the economic evaluation of costs and profits in case of the implementation of the suggested feed ration into practice in order to quantify the difference compared to the commonly used feed ration.
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Comperison quality of eggs depending on form of feeding
PROCHÁZKOVÁ, Alice
The topic of my dissertation is Comparison of the quality of eggs depending on the method of feeding. The aim of this study was to investigate whether the quality of hen eggs changes after adding crushed grape seeds in the compound feed of the hens. Grape seeds are formed as a side product during wine making processes and contain large amounts of biologically active substances and suitable acids, which can improve the feed conversion and subsequently also improve the technological properties of eggs. With processing of grape seeds the effective utilization of crop residues in vineyards comes about. The experiment was conducted in two experimental periods and in each period 100 laying hens were surveyed. They were separated into two groups an experimental and a control one. In the control group the hens were fed with a standard mixture of N2 feed and in the experimental group there was a supplement of 5 weight percent of crushed grape seeds in the compound feed. Eggs were collected daily and once every two weeks an analysis of technological properties of eggs was conducted. The results of the experiment showed that the addition of crushed grape seeds containing a biologically active substance did not have a statistically significant effect on the quality and selected technological parameters of eggs.
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Morphological analysis of the tapeworms eggs of the order Diphyllobothriidea
LEŠTINOVÁ, Kateřina
The order Diphyllobothriidea is a unique group of tapeworms in terms of the wide spectrum of definitive hosts involving all groups of tetrapods including man. They are almost globally distributed in both freshwater and marine ecosystems, but there are also terrestrial species. It is very difficult to identify species of diphyllobothriid cestodes to the species level. Morphology of the eggs might represent a new method in the differential diagnosis of these parasites. Besides the size and shape of the eggs, the structure of egg surface might play a significant role in the determination of different taxa. For the analysis of these characteristics Scanning Electron Microscopy (SEM) was used. Experimental infections in hamsters and man were done.
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Analysis of the commercial properties of an ostrich
KULÍK, Pavel
This thesis deals with the problem of commercial properties of an African ostrich collected on farms in the Czech Republic. Literature review focuses on the history, origin, economic benefits and also the breeding conditions. This work evaluates the utility of selected properties of ostrich farms in the Czech Republic. The values obtained were well described and evaluated by appropriate methods. Egg-laying farms was observed in the range from 15 to 50 pieces (mean 29.07 pieces), the weight of eggs ranged from 1.22 to 1.89 kg (mean 1.51 kg), fertilization of eggs were in the range from 54.55?86.00% (mean 76.36%) and a hatching rate was in the range of 31.82?52.77% (mean 44.61%). Weight of meat obtained from slaughter ostrich ranged from 30 to 50 kg (mean 39.74 kg), the skin area was in the range from 1.10 to 1.50 m2 (mean 1,34 m2) and the production of feathers was from 1.36 to 1.50 kg.
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Location of Balbani cytoplasm in sturgeon eggs as primordial gonocytes precursor during fertilization
DVOŘÁK, Matěj
The oocytes of many organisms, including fish, contain germ plasm. Germ plasm is maternally inherited determinants of germ cells. New-found germ plasm has been also described in previtellogenic sturgeon oocytes as Balbani cytoplasm. It contains precursors of germinal granules so called nuage. Germinal granules have been detected as a part of primordial gonocytes (PGCs) and according to some studies it play the role in the formation PGCs. PGCs are embryonic cells from which the gametes are differentiated. These cells has potential to transmit genetic information to the next generation. PGCs or subsequently spermatogonia therefore have the potential to be of value for gene banking and cryopreservation, particularly via the production of donor gametes with germ?line chimeras. Nevertheless the first step for successfully transplantation is visualization of PGCs. It is usually done using injection of GFP (green fluorescent protein) mRNA conjugated with mRNA, such as vasa and nanos, to the area of egg with PGC precursor localization (nuage) early after fertilization. Electron microscopic observation at this study revealed three main principal layers (a topmost alveolar layer, a zona radiata externa and a downmost layer as an zona radiata interna), a layer of cortical granules in unfertilized eggs and a perivitelline space in fertilized eggs; then germ plasm, containing nuage, which was dispersed only in the vegetal pole of ovulated sturgeon eggs. In addition, we observed formation interspace between the zona radiata externa and zona radiata interna. Sturgeon eggs have too strong envelopes for injection by glass needle. The glass capillary needle penetration could be facilitated by separation of parts of the egg envelopes as the alveolar layer and the zona radiata externa from interspace, which created by separation of the zona radiata externa and zona radiate interna by tweezers.
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