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Mechanismy působení nízkomolekulárních a vysokomolekulárních cyto-protektivních látek při vystavení hmyzího organismu nízkým teplotám.
HŮLA, Petr
Low temperatures limit the viability of cells, tissues and whole organisms. Temperate and polar insects overwinter with body temperatures below 0°C, sometimes with ice crystals in their hemolymph. Extracelular freezing is linked with cell osmotic dehydration. Thus, the freeze-tolerant insects had to evolve complex adaptation, including seasonal accumulation of low- and high-molecular substances, to protect their tissues against deleterious effects of cell freeze-dehydration. The mechanisms by which different substances exert their cryoprotective roles are theoretically diverse but practically poorly studied. In this thesis, I present results of metabolomic and transcriptomic analyses of putative cryoprotectants in the freeze-tolerant larvae of drosophilid fly, Chymomyza costata that accumulate in their hemolymph and tissues in response to cooling and drying. The functional aspects of low- (mainly proline and trehalose) and high- molecular substances (mainly LEA-like proteins) are considered.
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Vliv epigenetických faktorů při indukci diapauzy hmyzu
HŮLA, Petr
The aim of this study was to help answering the question whether the epigenetic modifications do influence induction of larval diapause in drosophilid fly, Chymomyza costata. The search in transcriptomic database revealed 210 genes potentially acting in epigenetic modifications. A single gene, dpy-30, showed by far most pronounced response to photoperiod. As a key component of H3K4 methyltransferase, the role of dpy-30 was examined by measuring global histone methylation (on histone 3 lysine 4, H3K4) in photoperiodically sensitive 3rd instar larvae of C. costata using three different methods. Although statistically significant difference was seen in the methylation level under two different photoperiodic conditions (long day vs. short day), the histones in cell nuclei of two tissues (muscle, fat body) showed slightly higher level of methylation under short days, which was contrary to our expectation.
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Ecohydromorphological survey of streams in nature protected areas: application in the Klíčava River catchment
Šilhánová, Věra ; Matoušková, Milada (advisor) ; Hůla, Petr (referee)
The focus of this thesis is on the application of ecohydromorphological survey of a small watercourses flowing through the Landscape Protected Area Křivoklátsko (LPA Křivoklátsko). A brief characterization of the study are, the catchment area of the Klíčava River, was written based on the study of literature as well as on the digital and analogue bases. The specificity of this region lies in the presence of the valley reservoir Klíčava, Lánská deer-park and the LPA Křivoklátsko. Two different methods of a stream habitat survey were applied, the Czech field survey method the EcoRivHab (Matoušková, 2003, 2007) and the River Habitat Survey - RHS (Environmental Agency, 1997, 2003) from the United Kingdom used in the UK and some other European states. This thesis examines the possibility of the application of these methods on a small watercourse running through a hilly country with a significant proportion of natural reaches, which are situated mainly in the Lánská deer-park. These regions were used as models for definitions of reference localities. The most anthropogenically impacted reaches were localized in the upper part of the Klíčava catchment area, which has been in the recent past intensively used for agricultural purposes, nowadays it is only used extensively. This part of the watercourse has been...
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