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Algal and Cyanobacterial Adaptations to Low Temperature and Desiccation
Jimel, Matouš ; Elster, Josef (advisor) ; Košťál, Vladimír (referee)
Algae and cyanobacteria, due of their evolutionary antiquity, are widely distributed primary producers that can withstand extreme environmental stresses. Low temperature, freezing and melting, and desiccation and rewetting, are common stresses prevalent mainly in polar regions and in winter seasons of temperate areas. In terms of physiological effects, these types of stresses share similar effects or are closely related to one another. Low temperatures and desiccation exert a variety of stresses that need to be negated or lessened by adaptations. Specifically, adaptations to chill, freeze, and desiccation stresses will be discussed, as well as strategies that allow for stress avoidance or resistant morphological adaptations. In this thesis, characteristics, functions and mechanisms of these adaptations and stresses are reviewed, as well as potential biotechnological uses of said adaptations. Key words: algae, cyanobacteria, freezing, chill, desiccation, abiotic stress, cryoprotectants, osmoprotectants, akinetes, cryoinjury
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Microbial activity of deep subsurphace miocen sediments near Soklov
Galertová, Renata ; Frouz, Jan (advisor) ; Kryštůfek, Václav (referee)
In my diploma thesis I observed microbial activity in Miocene sediments collected at two different depths - 30 and 150 meters - in the "Družba" open-mine pit, which is located in Sokolov Brown Coal Basin. There were three different types of sediment: lamellar, amorphous and transitional. Samples were obtained under sterile conditions and following treatments were applied to the transitional sediment: addition of glucose, wetting and freezing. The aim of my study was to observe the activity of the original microflora at various depths and the impact of environmental factors that can affect the quarried claystones after being put on heaps. Microbial activity was evaluated by measuring released CO2 (titration). Obtained values of microbial activity did not show any differences between the respiration of sediments of different ages (depths), but differences between different types of sediments were significant, the highest values were found in lamellar sediment. Affection of samples then showed biota activity response suggesting that microbial communities at lower depths are limited by nutrients. Because the application of glucose did not show any noteworthy effect, we can assume that these communities are specialize on present fossil organic matter they are able to decompose, which is important especially in...
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Freezing
Ševčík, Andrej ; Chrobák, Ondřej (referee) ; Kvíčala, Petr (advisor)
The subject of diploma thesis is cycle of paintings, animation and video. This work is based on the operation system error. I focusing on well know phenomen of freezing computer and follow layering of system windows over themselves. Due to an error may arise aesthetic shape, which may refer to geometric abstraction. On this phenomenon interested me especially the elementary aspects of painting, building space on surface, geometry, movement and shape.
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Influence of Storage Conditions on Metabolic Profile of Apples
Duroňová, Kateřina ; Vávrová, Milada (referee) ; Kráčmar, Stanislav (referee) ; Márová, Ivana (advisor)
The goal of presented dissertation has been complex analysis of changes in content of fatty acids, enzymatic and low-molecular antioxidants in apples and related evaluation of perception of originators of storage diseases for apples stored in various conditions. Main part of the work has been dedicated to study of the impact of storage of apples in modified atmosphere with reduced amount of oxygen and in reference “normal” atmosphere for six months. Next part of the work has been dedicated to study how apple storage in common, consumer affordable, conditions (storage in a cellar, in a refrigerator, and in room temperature) affects content of low-molecular antioxidants. For testing has been selected apple kinds Jonagored, Golden Delicious, Idared, Šampion, and Granny Smith. Within the scope of this work has been optimized the method for determination of fatty acids in plant material with higher content of wax. The measured values imply the apples are valuable source of many important nutrition substances like vitamins, provitamins and antioxidants. During the storage process these substances exhibit considerable protective function. Long-term storage, mainly in the atmosphere with reduced amount of oxygen (FAN), enables preservation of majority of these important nutrition substances depending on the kind of apple and conditions of storage. Freezing process is conservative to apples (mainly in the presence of protective substances), while in the process of drying the values of all monitored antioxidants decrease depending on temperature and conditions of drying. Upon the choice of the storage method one must consider nutrition, sensoric characteristic and consumer demands.
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Low Temperature and Cryogenic Treatment of Casehardened Parts
Bílková, Lenka ; Juliš, Martin (referee) ; Kouřil, Miloslav (advisor)
This work deals with the assessment of the influence of low-temperature treatment on the structure and properties of casehardened surface layer of parts. The objective was to assess whether low-temperature treatment is sufficient, insufficient, or unnecessary for the given purpose. Gears which form a part of Zetor tractors gear boxes were used as samples. Thirteen pairs of frozen and non-frozen samples were used; they were taken from production batches throughout 2007, their hardness was assessed and furthermore, the experiment itself, freezing casehardened and hardened samples to different temperatures reaching as low as -196°C, was carried out. A moderate increase in hardness was registered with the majority of the frozen samples, which proved the effectiveness of the low-temperature treatment.
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Changes in selected local fruits during freezing.
Matějková, Markéta ; Melounová, Jitka (referee) ; Márová, Ivana (advisor)
This diploma thesis was focused on study of low-molecular antioxidants present in various kinds of fruits, namely berries. In theoretical part detailed characterization of antioxidants studied in presented work and their biological effects are introduced. Further, principals of processing and storage of specified species of fruits are discussed. Changes observed during storage of specific fruits are described too. In practical part changes in content of selected antioxidants in berries were followed. As studied material strawberries, raspberries, blueberries, red and black currants were used. All kind of these fruits was stored in fridge for six months using several different kind of processing. Berries were stored as whole fruits, whole osmotically processed fruits by sucrose, raw pulp and sweetened pulp. At first, starting values of selected antioxidant parameters were measured in fresh fruits (ascorbate, total antioxidant activity, total phenolics, catechins and individual flavonoids). After freezing the same parameters were measured regularly in two month periods. As the most suitable method of fruit processing, with regard to antioxidant content, storage of the whole fruits or pulp can be recommended. Content of ascorbate decreased in all forms and species of the processed fruits during all the time of storage. Oppositely, the content of other studied antioxidants exhibited fluctuations or increasing trend. Sensory analysis was proved for the whole fruits and also for whole sweetened fruits.
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Changes of enzyme activities in fruits during long-term storage
Ferdová, Jitka ; Melounová,, Jitka (referee) ; Márová, Ivana (advisor)
This study is focused on study of changes of enzyme and low-molecular weight antioxidants in different fruits during long-term storage. In theoretical part individual low-molecular weight antioxidants and enzymes are described. The main causes of fruit decay and some possibilities of fruit preservation and storage are summarized. As biological material some common fruits were chosen - green and red apples, peaches, plums and white grapes. The fruits were stored in laboratory, cellar, in refrigerator and in freezer. In freezing experiments some ways of fruit preparation and processing were tested and their influence on fruit antioxidant status was compared. Shortened storage experiment was applied on blueberries, cranberries, raspberries and strawberries too. In fruits some group parameters – total antioxidant status, dry mass content, ascorbate level, total flavonoids and total phenolics were analyzed spectrophotometrically. Individual flavonoids and phenolics were determined by RP-HPLC/UV-VIS and on-line LC/PDA/ESI-MS. Antioxidant enzyme activities (superoxide dismutase SOD, catalase CAT, polyphenol oxidase PPO and lipoxygenase LOX) were measured by spectrophotometry. The surface microscopy and cultivation of moulds from fruit surface were performed too. Influence of storage conditions on biological activities is dependent on fruit sort. Freezing is the most suitable procedure for long-term storage without significant changes of active substance content. Long-term storage in controlled temperature conditions and/or atmosphere is usable for fruits with longer storage period. In these fruits stabile levels of antioxidant enzymes are stored for relatively long time. Some of enzymes act synergistically. Enzyme activities differed according to storage phase; at the beginning mainly high SOD and LOX activities were observed. CAT and PPO are probably activated as defence systems in rippened and/or damaged fruits. Levels of total as well as individual low molecular weight antioxidants varied during storage in all sorts, generally, increased course with longer storage period can be observed.
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Funktional Effects Improve of Artifical Casings in Meat Production.
BURIAN, Rudolf
The aim of this work is to capture the evolution of functional characteristics of plastic casings used in the meat industry. The first part deals with the history and development of casings as a packaging material and the functional characteristics of plastic casings in general. The second part introduces plastic casings produced by Viscofan Ltd. České Budejovice, focusing on their functional properties, methods for detecting these properties, possibilities of their usage in the meat industry, their processing and influence on extending shelf-life of meat products during storage at low temperatures.
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Possibilities affection the texture of meat common carp (Cyprinus carpio)
SUCHÁNEK, David
Texture was measured on texture analyzer TA.XT plus the manufacturer's Stable Micro System, using the methods of texture profile analysis (TPA) in the general carp fillets (Cyprinus carpio). Were measured basic textural properties such as hardness, chewiness, springiness and cohesiveness. Course of change of these textural characteristics were monitored during the freezing and marinating. In both cases, the differences statistically substantiating some textural properties.
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