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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Stanovení vybraných "Musk" sloučenin v biotických vzorcích / Determination of selected musk compounds in biotic samples

Blahová, Eliška January 2008 (has links)
Musk compounds (MUSK) or synthetic fragrances are organic substances commonly used as fragrant constituents of detergents, soaps, cosmetics, personal care products, industrial and in-house cleaning agents, industrial plasticizers, chewing tobacco and fresheners. The big attention is pushed ahead studying these compounds, their fate in different parts of ecosystems and studying their characteristics at present, because musks infiltrate many environmental components, particularly aquatic and marine ecosystems, through their large application and their ability to be perzistant. This diploma thesis was focused on four synthetic “classical” fragrances used over the world. The aim of this study was to perform a method optimisation for the determination of selected fragrances in biotic matrix. There was made an evalution of ability of selected water treatment plant to clear away musks from water, these results were used for evaluating contamination measurement of aquatic ecosystem. The identification and quantification of analytes was carried out by high resolution gas chromatography - mass spectrometry (HRGC/MS).
72

Krasová polje východní Hercegoviny z perspektivy ryby rodu Telestes / Telestes perspective on the karstic poljes of eastern Herzegovina

Doulíková, Tereza January 2019 (has links)
The Dinaric karst region in the Balkans is one of the hot spots of biodiversity with a high number of endemic freshwater fish. The major cause of the high degree of endemism are numerous paleoclimatic and geological events that have affected the formation of the entire area. Flows of karst poljes represent a specific ecosystem to which some fishes have adapted. The poljes have been periodically flooded and these floods may activate different underground channels, which lead to interconnection of poljes. These fish species spend a part of the year in surface water and a part in groundwater and they may use the underground flows between poljes for migration. The aim of this thesis is to evaluate the genetic variability of two endemic fish species of the genus Telestes living in karst poljes in the region of eastern Herzegovina, and to detect a possible current gene flow between populations of these species due to the connection of underground flows. For this purpose, the DNA from 102 individuals from five different localities was isolated. The mitochondrial marker cytochrom b and 16 microsatellite loci were used for the analyses. The results point to very low variability between species and populations. Based on mitochondrial marker analysis, no link between populations of the species was detected,...
73

Srovnání kraniální skeletogeneze a odontogeneze bazálních zástupců paprskoploutvých ryb / Comparative analyses of cranial skeletogenesis and odontogenesis in basal Ray-finned fishes

Pospíšilová, Anna January 2020 (has links)
Skeletal (cartilaginous, bony, and dental) tissues undoubtedly exemplify the key innovation of vertebrates. Among all recent vertebrates, the most numerous and successful lineage is represented by the Ray-finned fishes that, accordingly, exhibit amazing variety of skeletal architectures and phenotypic adaptations. In order to depict fundamental principles of fish cranial skeletogenesis the developmental formation of skeletal architectures was described, compared and analyzed using members of early branching fish lineages, that exemplify very different strategies of skeletogenesis. While the Senegal bichirs and the Tropical gars are heavily armored forms with massive exoskeleton and hyperossified dental structures covering the whole oropharyngeal region, the European sterlets, on the contrary, possess mostly cartilaginous skeleton and reduce their dental structures during early development. Whole analysis is underpinned by the Northen pike, teleostean species with lightened skeletal architecture with comparable number of cranial elements. The present study represents the first complex comparative analysis of their skeletogenesis and odontogenesis. This allowed to define developmental strategies founding different lineage-specific skeletal architecture of vertebrates. Comparative description of...
74

Persistentní organické polutanty v životním prostředí Jihomoravského kraje / Persistent Organic Pollutants in the Environment of the Southern Moravia Region

Lána, Radim January 2008 (has links)
Byla provedena studie bioakumulace POP v potravním řetězci a historických trendů hladin POP v sedimentech Brněnské přehrady. Současné úrovně kontaminantů byly stanoveny v jelci tloušti z řeky Svratky a rovněž byla posouzena hygienická kvalita ryb z rekreačního rybolovu. Současné úrovně POP v terestrickém ekosystému byly posouzeny pomocí analýz jehličí jako přirozeného indikátoru znečištění. Studium jedinců tří druhů dravých ptáků z ČR bylo zaměřeno na zhodnocení kontaminace těchto vrcholných predátorů POP. S pomocí analýz vybraných druhů ryb ze Záhlinických rybníků byl rovněž studován proces bioakumulace. Posouzení parametrů dvou moderních extrakčních technik a jejich využitelnosti pro izolaci POP z různých matric bylo námětem poslední části dizertace.
75

Hodnocení stability rybničního ekosystému v Národní přírodní rezervaci Řežabinec / The assessment of the NPR Řežabinec pond ecosystem stability.

ŠRÁMEK, Pavel January 2014 (has links)
The first part is characterized by a pond ecosystem and National Nature Reserve Řežabinec in terms of its historical development and creation. Are mentioned methods , the method and system of protection of the site. The paper describes a method of fish farming during the period of the individual plans of care farming in the last five years and the water conditions in the area . The ecosystem is assessed on the basis of available data in the literature to me In our own work we focus on monitoring water chemistry and state recovery tank , especially in terms of development and biomass of zooplankton species representation in the course of one growing season. He also details the fishing and agricultural management and water management conditions in the locality. Marginally judging submerged and littoral vegetation and the presence of water birds. This work demonstrated the dependence of the size of the fish stock on the frequency of a generic representation of zooplankton and the positive impact of lower stocking on the development and stability of the entire ecosystem. Contributes to the stability and sensitive farming in the last period.
76

Vliv pyrethroidových pesticidů na ryby / The effect of pyrethroid based pesticides on fish

RICHTEROVÁ, Zuzana January 2016 (has links)
Pyrethroids are ones of the most used pesticides worldwides. The widespread use and high stability of pyrethroids lead to the assumption of that their occurrence in the environment could be quite frequent. They can reach water ecosystem as pollutants. Residues of pyrethroids are not only detected in the water column, but also in sediments and in fish tissues. The first study was devoted to the product Nexide containing 60 g.l-1 of active substance gamma-cyhalothrin. Tested Nexide concentrations were 5, 25, 50, 100, and 250 &microg.l-1. Early life stage test was used.Common carp (Cyprinus carpio) was tested. There were significant mortalities in all concentrations except the lowest concentration during the trial. The lowest concentration tested 5 &microg.l-1 only caused a slightly increased mortality. This lowest concentration influenced the growth in length and weight negatively, decelerated ontogenetic development, and made the body surface of the individuals darker. Histopathology of individuals from this concentration revealed dystrophy in liver. Examination of kidney, intestine and gills did not show significant histopathological differences compared with control. The evaluation of selected parameters of oxidative stress demonstrated a significantly higher activity of detoxification enzyme glutathione-S.transferase (GST) and a significantly lower activity of defensive enzyme glutathione peroxidase (GPx) compared with the control group. The other examined parameters of oxidative stress such as catalase (CAT), glutation reductase (GR), and lipid peroxidation determined by using the thiobarbituric acid-reactive substances (TBARs) were comparable to the control group. Changes in oxidative stress parameters suggest that exposure of the organism to the product Nexide in the given concentration leads to dysbalance of defensive enzymes. The second study was devoted to the product Cyperkill 25 EC containing 250 g.l-1. Tested Cyperkill 25 EC concentrations were 7.2, 36, 72, 144, and 360 &microg.l-1. The procedure of the trial was the same as the preceded one. There were 100% mortalities in all concentrations except the lowest concentration during the trial. The lowest tested concentration 7.2 &microg.l-1 allowed 90% of individuals to stay alive till the end of experiment. The lowest concentration influenced the growth in length and weight negatively and decelerated ontogenetic development compared with the control. Any individual exposed to this concentration did not reach juvenile stage until the end of the trial. Dark pigmentation was visible in 68% of these exposed individuals on the last day. Similar darkening was visible in individuals from higher concentrations shortly before death too. Histological examination did not revealed significant changes in intestine, liver, kidney, and gills compared with the control group. Evaluation of selected parameters of oxidative stress demonstrated significantly lower activities of GST, GR, and GPx. Activities of CAT and TBARS were comparable with the control group. Changes in oxidative stress parameters suggest that exposure of the organism to the product Cyperkill 25 EC in the given concentration could induce oxidative stress and interfere with the activities of antioxidant enzymes. The presented thesis summarises actual data about pyrethroids and their influence on fish. The demonstrated effects confirm high susceptibility of early developmental stages of fish to tested pesticides. When interpreting the results, we have to take into account the fact that studies showed this risk even on single pyrethroid substances. But water organisms are exposed to many other more or less toxic products and substances in a real environment. These xenobiotics could react with each other and their mixture could even potentiate negative effects. The performed studies also clearly show the significant differences in the sensitivity of embryonic and embryolarval tests.
77

Tvorba biogenních aminů v mase vybraných druhů ryb / The formation of biogenic amines in flesh of selected fish species

MATĚJKOVÁ, Kateřina January 2013 (has links)
The thesis deals with the use and effectiveness of some less common methods of conservation of fish meat. The formation of biogenic amines in meat is observed in connection with the non-traditional preservative methods. Amines can serve as indicators of protein degradation. The quality of fish was considered in connection with the increasing content of selected biogenic amines (putrescine, cadaverine, spermidine, spermine, 2-fenylathylamine, histamine, tyramine and tryptamine). Ultra performance liquid chromatography (UPLC) was used as the method for determination of biogenic amines. Amines were derivatized by dansylchloride before their UPLC separation. The fish flesh was vacuum-packed. Samples were stored for several weeks in a thermostat at the selected storage temperature after the application of selected preservative technique. Beta-irradiation and high hydrostatic pressure were used for the preservation of fish flesh. Control samples were not exposed to the â-irradiation and high pressure. The organoleptic properties were studied for all samples (smell/odor, insight and shape). Beta-irradiation was applied to fish meat of common carp (Cyprinus carpio) and rainbow trout (Oncorhynchus mykiss). Both these species of freshwater fish are economically significant. Carp and trout are the species being mostly consumed in the Czech Republic. Fish meat is considered to be provided the flesh is fresh. A testing series of samples was created with common carp to determine the appropriate dose of â-irradiation. The maximum permissible dose of irradiation for fish meat is 3 kGy. Fish samples were exposed this dose in the first experiment. The dose of irradiation was reduced in following experiments based on the experience from the initial experiment. The doses of 0.25, 0.5, 0.75, 1.0 and 2.0 kGy were applied to rainbow trout. The value of 0.75 kGy of â-irradiation or higher (1.0, 2.0 and 3.0 kGy) prolonged the shelf life of fish meat, which was stored for three months (98 days). Prolonging of the shelf life of fish meat to approximately 98 days at 3.5 °C is redundant from technical point of view. For that reason lower doses 0.25, 0.5 and 0.75 kGy were tested in more detail in the repeated experiment with carp meat. Lower doses of â-irradiation are considered to be more acceptable and-at the same time-sufficiently effective for delaying the beginning of degradation processes. 6 High hydrostatic pressure was applied to meat of common carp (Cyprinus carpio), rainbow trout (Oncorhynchus mykiss) and pike (Exos lucius). Pike is another very popular kind of freshwater fish. Pike flesh is very tasty, but in spite of this, pike is not so much popular among consumers compared to carp and trout. The cause is its high price. Samples of pike were stored at standard temperature 3.5 °C and also at higher temperature 12 °C (unlike experiments with â-irradiation). Lower temperature of storage (3.5 °C) followed the conditions of storing of fish meat in industrial refrigeration facilities and households. The high pressure might not be sufficient for preservation at higher storage temperatures. This assumption was based on available information. Samples were treated by high pressure and stored at both 3.5 °C and 12 °C to verify this assumption. Higher temperature simulated either failure of refrigeration equipment or unsuitable store temperature of meat. In all species selected freshwater fish two levels of high pressure were applied ? 300 and 500 MPa. Both levels had significantly reduced the formation of biogenic amines, especially in samples stored at 3.5 °C. At this temperature, the effect of 300 and 500 MPa delayed start of degradation processes in fish meat by 3?4 weeks. At 12 °C and 500 MPa, high pressure extended the sustainability of meat by no more than one week. 500 MPa is effective treatment at the lower temperature of 3.5 °C. High pressure is not reliable preservative techniques at higher temperature.
78

Vývoj a dynamika palatální a faryngeální dentice u jesetera malého / Development and dynamics of the palatal and pharyngeal dentition in sterlet

Novotná, Štěpánka January 2021 (has links)
Dentition is a key vertebrate innovation showing not only great morphological diversity, but also different maintenance or replacement of functional teeth. Most extant vertebrates replace their dentition through addition of new teeth from deeply invaginated epithelium, i.e. the successional dental lamina, due to presence of dental stem cells. However, in some early branching lineages of ray-finned fishes (Actinopterygii), new tooth germs arise from the adjacent superficial epithelium without the presence of the successional dental lamina. Whether the two types of dental development in vertebrates are equivalent and whether comparable dental stem cells play role in tooth replacement is currently not satisfactorily evaluated. This Master thesis aims at describing the development of palatal and pharyngeal dentition of a member of an early branching lineage of ray-finned fishes, the sterlet sturgeon (Acipenser ruthenus). The sterlet dentition is fairly dynamic. The teeth are replaced without the successional dental lamina, however, this replacement shows characteristics similar to those described in vertebrates with the successional dental lamina. A marker of dental stem/progenitor cells, Sox2, is localized in the outer dental epithelium of the predecessor tooth in the vicinity of the adjacent taste...
79

Stanovení musk sloučenin v biotických matricích / Determination of musk compounds in biotic matrices

Soukupová, Alena January 2011 (has links)
This diploma thesis deals with actual issues of the contamination in the environment with synthetic fragrances. Musk compounds are infiltrated to many environmental components (especially an aquatic ecosystem) because of their biological persistence and the ability of accumulation. This diploma thesis is focused on the selection and the optimization of method for the determination of musk compounds in real biotic matrices (fish). The isolation of analytes was realized by PSE method and the purification of extract was realized by the method of the adsorption column chromatography. Identification and quantification of individual musk compounds was carried out by GC-MS. In conclusion were results and the contamination of fish from the river Svratka disscissed and evaluated. These fish were caught at the inflow and at the outflow of the wastewater treatment plant.
80

Studium průniku „musk“ sloučenin do abiotických a biotických složek vodních ekosystémů / Study of Transfer of Musk Compounds in Abiotic and Biotic Components of Aquatic Ecosystems

Zouhar, Libor January 2013 (has links)
This work was focused on the determination of musk compounds in various components of the environment. Synthetic musk compounds are organic substances commonly used as fragrant constituents of detergents, perfumes, cosmetics and other personal care products (PCPs). These compounds contaminate the aquatic environment through municipal wastewater from sewage treatment plants. The result is accumulation of these analytes in the environment and their occurrence in food chain. Synthetic fragrances are commonly detected also in human body; these substances generally belong among relatively new persistent organic pollutants (POPs) because of their persistence, bioaccumulation, and potential toxicity. The aim of this work was to optimize the methods for the determination of selected synthetic fragrances in wastewater (municipal, industrial) and in fish muscle. These analytes were determined in wastewater [the wastewater treatment plant (WWTP) Brno – Modřice, cosmetic manufacturing plant] and in fish Squalius cephalus that had been caught in the river Svratka. The selected analytes (14 substances) originate from the group of nitromusk, polycyclic musk and linear musk compounds. Solid phase microextraction (SPME) [for wastewater samples] and pressurized solvent extraction (PSE) [for fish samples] were used for isolation of analytes from real samples. The identification and quantification of analytes were carried out by high resolution gas chromatography coupled with mass spectrometry detection (GC-MS). The results show that galaxolide (g.L-1) and tonalide (tenths of g.L-1) were polycyclic musk compounds which were found at the highest concentration level in influent and also in effluent samples from the WWTP Brno – Modřice. The most extended nitromusk compound was musk ketone (hundredths of g.L-1). Linear musk compounds were detected in all influent samples (g.L-1). The overall removal efficiency of synthetic musk compounds from wastewater in the WWTP varies within the following ranges: nitromusk compounds 34.4 % – 85.4 %, polycyclic musk compounds 36.7 % – 53.3 % and linear musk compounds 90.5 % – 99.9 %. On the basis of the results it can be stated that wastewater (effluent from the WWTP) is the primary source of musk compounds, especially of the polycyclic ones in the environment. It has been also shown that ultrafiltration used in a cosmetic plant is a highly efficient technology for removing nitromusk and polycyclic musk compounds from industry wastewater. The results from evaluation of the fish contamination by musk compounds show that galaxolide was the substance which reached the highest concentration levels (tens of g.kg-1 l.w.). The results corroborate ubiquitous occurrence of musk compounds in the environment and reduction of using of nitromusk compounds due to their potential toxic properties. It has been shown that the insufficiency of the purifying procedures used in the WWTP Brno – Modřice has a significant influence on the concentration level of polycyclic musk compounds (tonalide, galaxolide) in fish caught from the river Svratka.

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