Submitted by LEONARDO WARZEA LIMA null (leowlima@yahoo.com.br) on 2016-05-27T12:41:13Z No. of bitstreams: 1 Dissertação. Revised.pdf: 1863234 bytes, checksum: 639af080fd660e2648e06a1ee397d972 (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-05-30T20:13:44Z (GMT) No. of bitstreams: 1 lima_lw_me_jabo.pdf: 1863234 bytes, checksum: 639af080fd660e2648e06a1ee397d972 (MD5) / Made available in DSpace on 2016-05-30T20:13:44Z (GMT). No. of bitstreams: 1 lima_lw_me_jabo.pdf: 1863234 bytes, checksum: 639af080fd660e2648e06a1ee397d972 (MD5) Previous issue date: 2016-05-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / As plantas não possuem mecanismos de defesa específicos para combater a diversidade de estresses abióticos e poluentes do ambiente, e sua sobrevivência depende da flexibilidade e adaptação dos seus próprios mecanismos de defesa naturais. Além disso, a manutenção da homeostase celular depende de vários mecanismos interligados e complexos, enquanto o sistema de defesa celular não segue um padrão específico de ação e pode ainda variar devido a vários fatores tais como a espécie do vegetal, o tempo de exposição ao estresse, o estágio de desenvolvimento da planta e também nos diferentes órgãos e tecidos analisados. Com base nessas considerações, esta dissertação teve como objetivo destacar e investigar o papel do Enxofre (S) e do Selênio (Se) contra diferentes estresses nas plantas, através das respostas enzimáticas, não enzimáticas e também outros mecanismos de defesa relacionados. No primeiro capítulo, o autor caracteriza os mecanismos bioquímicos gerais da defesa celular antioxidante, especificamente a formação das espécies reativas de oxigênio (EROs) e suas singularidades químicas e o estresse oxidativo induzido, o sistema de defesa antioxidante enzimático, especificamente as enzimas Superóxido Dismutase (SOD) e a Catalase (CAT), os mecanismos não-enzimáticas contra o estresse, incluindo o ciclo Aascorbato-Glutationa, a GSH (glutationa reduzida), as fitoquelatinas e também a formação de prolina. O estado nutricional da planta durante o estresse é crucial a fim de manter uma resposta de defesa adequada. Em vista disso, o capítulo dois apresenta uma revisão sobre a participação de Enxofre (S) na defesa contra o estresse. Este nutriente tem um papel importante em processos fundamentais, tais como o transporte de elétrons, estrutura, regulação, produção de oxigênio fotossintético, resistência a estresses abióticos e bióticos e no metabolismo secundário. Além disso, alguns elementos químicos são considerados benéficos para as plantas, no qual o Selênio (Se) é o mais relevante. No capítulo três, o autor descreve o papel do Se na amenização do estresse induzido pela contaminação por metais pesados, suas poderosas características antioxidantes, a melhoria da atividade de enzimas antioxidantes e também dos mecanismos globais de defesa. O capítulo quatro consiste em um projeto científico conduzido pelo autor. O objetivo deste estudo foi investigar se o Selênio, sob a forma de selenito (Na2SeO3), é capaz de evitar a absorção, translocação e concentração de cádmio (CdCl2), em diferentes tecidos no tomate, indicando os possíveis mecanismos para amenizar o estresse, bem como também analisar o estado geral dos frutos através das análises nutricionais, peso seco, pigmentos e concentração de Prolina livre. Os resultados demonstram que efeito atenuante do Se em tomateiro submetido ao Cd poderia estar relacionado com a restrição da absorção e translocação de Cd2+, aumentando a concentração de micronutrientes nos frutos e, finalmente, aumentando a concentração de prolina livre nos frutos. / Plants do not have specific defense mechanisms to counteract the diverse range of abiotic stresses and pollutants into the environment, and its survival depends on the flexibility and adaptability of its own natural defense mechanisms. Furthermore, the maintenance of cellular homeostasis depends on several interlinked and complex mechanisms, while the cellular defense system does not follow a specific pattern of action and may differ due to various factors such as plant species, exposure time to the stress, plant developmental stage, different organs and tissues analyzed. In the light of these considerations, this dissertation aimed to highlight and investigate the role of Sulfur and Selenium against different plant stresses, through the enzymatic and non-enzymatic plant responses and other related defense mechanisms. In the first chapter the author characterize the general biochemical mechanisms of the antioxidant cell defense, specifically the reactive oxygen species (EROs) formation and its chemical singularities and the induced oxidative stress, the enzymatic antioxidant defense system, specifically the superoxide dismutase (SOD) and Catalase (CAT) enzymes, the non-enzymatic mechanisms against the stress, including the Ascorbate-Glutathione cycle, the GSH (reduced glutathione), the phytochelatins and also proline formation. The plant nutritional status during the stress is crucial in order to maintain a proper defense response. In view of this, the chapter two is a published review about the participation of Sulfur (S) on the stress defense. This nutrient has a role in fundamental processes such as electron transport, structure, regulation and it is also associated with photosynthetic oxygen production, abiotic and biotic stress resistance and secondary metabolism. Moreover, few chemical elements are considered benefic to plants, while Selenium (Se) is the most relevant. In the chapter three the author describes the role of Se to detoxify the stress induced by heavy metal contamination, its powerful antioxidant characteristics and the improvement of the antioxidant enzymes activity and overall defense mechanisms. The chapter four consists of a scientific project conducted by the author. The aim of this study was to investigate whether Selenium, under the form of selenite (Na2SeO3), may avoid the uptake, translocation and concentration of Cadmium (CdCl2), in different tomato tissues, indicating possible mechanisms to counteract the stress, as well as to analyze the fruits overall status through the nutritional analyses, dry weight, pigments and proline concentration. The results demonstrate that alleviating effect of Se in tomato under Cd contamination could be related to restriction of Cd2+ uptake and translocation, enhancing micronutrient concentration in fruits and, finally, enhancing fruit proline concentration. / CAPES: 445978/2014-7

abstract: Photosynthesis is the primary source of energy for most living organisms. Light harvesting complexes (LHC) play a vital role in harvesting sunlight and passing it on to the protein complexes of the electron transfer chain which create the electrochemical potential across the membrane which drives ATP synthesis. phycobilisomes (PBS) are the most important LHCs in cyanobacteria. PBS is a complex of three light harvesting proteins: phycoerythrin (PE), phycocyanin (PC) and allophycocyanin (APC). This work has been done on a newly discovered cyanobacterium called Leptolyngbya Heron Island (L.HI). This study has three important goals: 1) Sequencing, assembly and annotation of the L.HI genome - Since this is a newly discovered cyanobacterium, its genome was not previously elucidated. Illumina sequencing, a type of next generation sequencing (NGS) technology was employed to sequence the genome. Unfortunately, the natural isolate contained other contaminating and potentially symbiotic bacterial populations. A novel bioinformatics strategy for separating DNA from contaminating bacterial populations from that of L.HI was devised which involves a combination of tetranucleotide frequency, %(G+C), BLAST analysis and gene annotation. 2) Structural elucidation of phycoerythrin - Phycoerythrin is the most important protein in the PBS assembly because it is one of the few light harvesting proteins which absorbs green light. The protein was crystallized and its structure solved to a resolution of 2Å. This protein contains two chemically distinct types of chromophores: phycourobilin and phycoerythrobilin. Energy transfer calculations indicate that there is unidirectional flow of energy from phycourobilin to phycoerythrobilin. Energy transfer time constants using Forster energy transfer theory have been found to be consistent with experimental data available in literature. 3) Effect of chromatic acclimation on photosystems - Chromatic acclimation is a phenomenon in which an organism modulates the ratio of PE/PC with change in light conditions. Our investigation in case of L.HI has revealed that the PE is expressed more in green light than PC in red light. This leads to unequal harvesting of light in these two states. Therefore, photosystem II expression is increased in red-light acclimatized cells coupled with an increase in number of PBS. / Dissertation/Thesis / Ph.D. Chemistry 2014

and keywords The aim of this work was to evaluate the effect on rat myocardial β-adrenergic system of short-term (10 hours and 3 days) and long-term (5 weeks) cold exposure of rats with possible subsequent two-week recovery at normal temperature. The subtypes of β-adrenergic receptors (β-AR), their cognate G-proteins and adenylate cyclase have been characterized. β-AR are important components of cardiac regulatory mechanisms. They are involved in stimulating G-protein (Gs) and adenylate cyclase to increase cardiac contractility and frequency during stressful situations, including cold exposure. Heart tissue contains all three β-AR subtypes (β1-AR, β2-AR, β3-AR). While β1-AR couples with only Gs, β2-AR and β3-AR interact with the inhibitory G-protein (Gi). Electrophoresis and Western blotting showed a significant increase in β1-AR after a three-day exposure to cold. There was also a significant increase in β3-AR concentrations after a five-week cold exposure and this increase lasted for two weeks. There were no significant changes in the amnounts of β-AR cognate G-proteins (Gαs, Gβ, Gαi1/2 a Gαi3). In contrast, expression of adenylyl cyclase isoform V and VI significantly decreased during short-term exposure to cold. Using the saturation experiment with the β-antagonist [3H]CGP 12177, β-AR were...

Abstract The purpose of the study was to examine the amount of cold exposure and factors affecting it at the population level in Finland, to determine what type of cold acclimatisation, if any, develops in urban residents in winter, and to find out whether cold acclimatisation or acclimation has a functional significance on psychological or physical performance. Tasks of low physical activity requiring attention and concentration (cognition, postural control) were assessed in cold. In a cross-sectional population study Finns aged from 25 to 74 years (n=6,951) were queried of their wintertime outdoor exposure duration and factors affecting it. In experimental studies seasonal cold acclimatisation (thermal responses) and its effect on cognition were assessed in the laboratory, where 15 young urban subjects were exposed to cold in winter and summer in bright or dim light. A controlled cold acclimation trial (n=10) was performed to study the effects of repeated exposures to cold on cognitive performance and postural control in young urban subjects. In the Finnish population the average amount of cold exposure in winter represents 4% of the total time. Most of the cold exposure occurs during leisure time and in outdoor occupations (agriculture, forestry, mining, industry, construction). Factors explaining increased occupational cold exposure were: occupation, age and a lesser amount of education. Factors associated with more leisure-time cold exposure were: being employed in outdoor occupations, being a pensioner, housewife, unemployed, practising physical exercise, and reporting at least average health. The experimental studies showed seasonal differences and aggravated thermal responses in urban residents in winter, but did not detect habituation responses typical of cold acclimatisation. In both seasons, acute moderate cold exposure resulted in positive, negative or mixed effects on cognition, reflected as changes in response times and accuracy. Simple cognitive tasks were impaired in cold, and in complex tasks both negative, positive and mixed effects were observed. It is suggested that cold exposure affects cognition through different mechanisms related to either distraction or arousal. Cold exposure increased postural sway by 70-90%, suggesting impaired postural control. Repeated exposures to moderate cold, reducing stress and discomfort and dampening physiological responses, did not markedly affect cognitive performance or postural control.

Temperature variation affects most biological parameters from the molecular level to community structure and dynamics. Current studies on thermal biology assess how populations vary in response to environmental temperature, which can help determine how populations differentially respond to climate change. To date, temperature fluctuation effects on endothermic poikilotherms such as the common eastern bumblebee (Bombus impatiens) are unknown even though bumblebees are the most important natural pollinators in North America. A cold-acclimation experiment with B. impatiens colonies revealed individuals acclimated to 5°C or 10°C at night did not differ in resting metabolic rate, flight metabolic rate, wingbeat frequency, or morphological measurements, compared to the control group. Moreover, an infrared camera showed that all colonies maintained maximum nest temperature consistently above 36.8°C. A latitudinal sampling of flight metabolic rate and morphological measurements of B. impatiens from four locations spanning Ontario (N 45°; W 75°) to North Carolina (N 34°; W 77°) indicated no latitudinal trend in the measured variables. This study shows that bumblebees are well equipped to face a wide range of environmental temperatures, both in the short term and long term, and can use a combination of behavioural and physiological mechanisms to regulate body and nest temperatures. These results are reassuring on the direct effects of climate change on bumblebee ecology, but further studies on the indirect effect of temperature variation on North American bumblebees are required to predict future ecosystem dynamics.

Sous un climat tropical humide, l'augmentation de la température nocturne a été associée à une diminution du rendement chez le riz. Une des hypothèses sous-tendant cette diminution est l'augmentation du taux de respiration nocturne (Rn) diminuant les ressources carbonées disponibles pour la croissance de la plante. La respiration mitochondriale est communément divisée en deux composantes fonctionnelles :- la respiration de maintenance (Rm), qui est associée à toutes les réactions biochimiques requises pour entretenir la biomasse existante. Le taux de Rm doublerait suite à une augmentation de la température ambiante de 10°C (Q10 = 2) ;- la respiration de croissance (Rg), qui est associée à tous les processus impliqués dans la création de biomasse. Cette composante de la respiration est principalement dépendante de la disponibilité en carbohydrates dans la plante, et donc de la photosynthèse.Ce travail de thèse a pour objectifs de (1) déterminer l'effet instantané (sans acclimatation) et sur le long terme (acclimatation) de l'augmentation de la température nocturne, proche de celle prédite par les scénarios climatiques, sur la respiration et la production de biomasse et de grains, (2) évaluer le coût de Rn en terme de biomasse à l'échelle de la plante entière, (3) estimer la respiration de maintenance (Rm) et sa réponse à l'augmentation de la température, et (4) évaluer l'effet de la valeur Q10 sur la modélisation de la production en biomasse. Pour atteindre ces objectifs, trois expérimentations (dont une inexploitable) ont été conduites en serre, deux en chambres de culture et une au champ, à Montpellier (France) et à la station expérimentale de l'IRRI (International Rice Research Institute, Philippines). L'augmentation modérée de la température nocturne de 1.9°C au champ et 3.5°C en chambre de culture de l'initiation paniculaire à maturité, et de 3.8 à 5.4°C en serre du repiquage à maturité, a entraîné l'augmentation significative de Rn (+13 à +35%). Dans le même temps, cette augmentation n'a pas eu d'effet significatif sur la production de biomasse et de grains des écotypes indica et aus, mais la production en grains de l'écotype japonica a été significativement plus faible. Le coût en biomasse de la respiration, en conditions de température nocturne plus élevée, a augmenté légèrement mais n'a pas été associé à une variation significative de la production de biomasse. L'augmentation de la température nocturne sur le long terme (acclimatation) a eu un impact plus faible sur Rn (facteur de 1.14 à 1.67 entre 21 et 31°C) que l'augmentation instantanée (sans acclimatation) (facteur 2.4 entre 21 et 31°C). Le coût quotidien en biomasse de Rm, a été de 0.3 à 1.2% (feuilles complètement développées) et de 1.5 à 2.5% (plantules entières). La Rm a augmenté d'un facteur 1.49 entre 21 et 31°C et représentait environ 33% de la respiration nocturne. Ce facteur est plus faible que l'hypothèse du Q10 = 2 qui surestime les effets de l'augmentation des températures sur Rm.Le modèle d'analyse de sensibilité a montré que la valeur du coefficient Q10 a un rôle significatif dans la prédiction de la production de biomasse dans les modèles de culture. Le rendement simulé diminue de 9% (Q10 = 2) et de 5% (Q10 = 1.5) lorsque la température moyenne journalière augmente de 2°C. Ainsi, prendre en compte l'acclimatation dans la réponse des plantes à l'augmentation des températures est important pour augmenter la précision des modèles. L'augmentation de la précision des modèles passera aussi par l'analyse des variations de la respiration en conditions naturelles. / In tropical climate, increasing night temperature was reported to be associated with a decline in grain yield in rice. This can be partly due to an increase in night respiration rate (Rn) which causes a depletion of carbohydrate supply available for plant growth. Mitochondrial respiration is commonly divided in two functional components; - Maintenance respiration (Rm) which is associated with all biochemical reactions required to maintain existing biomass. The rate of this respiration component would double when ambient temperature increase by 10°C (Q10 = 2). - Growth respiration which is associated with all processes involved in establishment of new biomass. This respiration component is mainly driven by carbohydrate supply and thus, by the photosynthesis rate. The present work aims to (1) determine the effects of short-term (without acclimation) and long-term (with acclimation) increase in night temperature similar to that projected by future climate scenarios on vegetative biomass production and grain yield; (2) evaluate, in terms of loss of biomass, the cost of Rn at plant scale; (3) estimate the maintenance respiration rate (Rm) and its response to temperature; and (4) evaluate the impact of Q10 value on biomass production. To achieve these objectives, three experiments (one unexploitable) were conducted in greenhouses, two in growth chambers and one in the field, at Montpellier (France) or at the experimental station of IRRI (International Rice Research Institute). The moderate increase in night temperature from panicle initiation to maturity in the field by 1.9°C and in growth chambers by 3.5°C, and form transplanting to maturity in greenhouse experiments by 3.8 to 5.4°C, did affect significantly Rn that increased by 13 to 35%. In the same time, it did not affect significantly biomass production and grain yield for indica and aus cultivars, whereas grain production decline was observed for japonica. Calculated biomass losses due to increased Rn under increased night temperature were important but were not associated with a change in biomass production or grain yield. Effect of long-term exposure to increased night temperature (acclimation) was smaller (factor 1.14 to 1.67 between 21 to 31°C) than that of short-term exposure (without acclimation) (factor 2.4 between 21 to 31°C). In this work, 0.3 to 1.2% (expanded leaves) and 1.5 to 2.5% (whole seedlings) of existing dry biomass was lost daily to Rm. The Rn was composed by about 33% of Rm, which increased by factor 1.49 between 21 and 31°C. This is below the common assumption of Q10 = 2 that thus overestimates the effect of increasing night temperature on Rm.A model sensitivity analysis showed that the Q10 value is important in the prediction of biomass production in crop models. Yield is expected to decline by 9% (Q10 = 2 assumption) and by 5% (Q10 = 1.5 assumption) with increasing mean daily temperature by 2°C. Thus, taking into account the acclimation response to temperature change is important for models accuracy. Making crop models more accurate requires more knowledge thermal effect on respiration in the field.

Nos últimos anos é crescente o número de estudos que preocupam-se em compreender como as mudanças climáticas podem interferir no equilíbrio dos ecossistemas globais. Dentre as linhas de pesquisa destacam-se as avaliações de toxicidade química termo-dependente (TQTD) já que uma das principais previsões é o aumento da temperatura global. Esta variável ambiental por si só, pode influenciar processos biológicos essenciais de organismos aquáticos ectotérmicos modificando a sensibilidade frente ao estresse ambiental. No entanto, não se deve subestimar a capacidade dos organismos a lidar com condições ambientais adversas, por isso, estudos atuais estão considerando aspectos de aclimatação e adaptação a cenários desfavoráveis. A partir deste contexto, o presente trabalho teve como objetivo geral avaliar o efeito da aclimatação na toxicidade química termo-dependente para uma substância de referência (NaCl) e um herbicida (AKB®) que tem como princípio ativo o Glifosato, substância mais utilizada em agroquímicos no país. O organismo-teste utilizado foi o cladócero Ceriodaphnia silvestrii, organismo padronizado para testes ecotoxicológicos e que possui papel chave na cadeia trófica e ciclo de energia do sistema. Os experimentos foram realizados combinando a metodologia de testes padronizados utilizando três temperaturas (20ºC, 25ºC e 30ºC). A aclimatação foi avaliada através da exposição direta e parental a condições diferenciadas de temperatura. O endpoint foi a imobilidade dos organismos, sendo que a toxicidade e os efeitos da aclimatação foram analisados no programa R 3.3.2. Os resultados obtidos demonstraram um efeito significativo da temperatura na toxicidade de NaCl e do herbicida AKB® para Ceriodaphnia silvestrii. A tendência geral observada foi de TQTD positiva, com exceção da temperatura de origem 25ºC nos testes com o herbicida. A aclimatação promoveu diferenças tanto na toxicidade como na distribuição da sensibilidade dos organismos, evidenciando a importância de incorporá-la na avaliação da toxicidade termo-dependente de xenobióticos. / In recent years there has been a growing number of studies that are concerned with understanding how climate change can interfere with the balance of global ecosystems. Among the lines of research are the evaluations of temperature-dependent chemical toxicity (TDCT), since one of the main predictions is the increase in global temperature. This environmental variable alone can influence the essential biological processes of aquatic ectothermic organisms by modifying the sensitivity to environmental stress. However, the ability of organisms to deal with adverse environmental conditions should not be underestimated, so current studies are considering aspects of acclimation and adaptation to unfavorable scenarios. The objective of this study was to evaluate the effect of acclimation on the temperature-dependent chemical toxicity of a reference substance (NaCl) and an herbicide (AKB®) which has as its active ingredient glyphosate, the most used substance in agrochemicals in the country. The organism used was the cladoceran Ceriodaphnia silvestrii, standardized organism for ecotoxicological tests and which has key role in the trophic chain and energy cycle of the system. The experiments were performed by combining the standardized test methodology using three temperatures (20ºC, 25ºC and 30ºC). The acclimation was evaluated through direct and parental exposure to different temperature conditions. The endpoint was the immobility of the organisms, and the toxicity and effects of acclimation were analyzed in software R 3.3.2. The results showed a significant effect of temperature on the toxicity of NaCl and the herbicide AKB® for Ceriodaphnia silvestrii. The overall trend observed was positive TDCT, except for the 25°C source temperature in the tests with the herbicide. The acclimation promoted differences in the toxicity and the distribution of the sensitivity of the organisms, evidencing the importance of incorporating it in the evaluation of the temperature-dependent toxicity of xenobiotics.

Dans le contexte du changement climatique, l’augmentation de la fréquence et de l’intensité des canicules a un impact négatif sur la physiologie des plantes, du fait de la perturbation structurale des protéines et des membranes par les fortes températures. Au cours de cette thèse, nous avons développé et caractérisé un système expérimental original dans lequel des plantules d’Arabidopsis thaliana sont arrêtées dans leur développement du fait d’une carence minérale. Ces plantules présentent une grande plasticité métabolique, notamment au niveau énergétique, qui leur permet de survivre pendant des semaines en état stationnaire. Nous avons ensuite réalisé une étude intégrative des processus qui permettent à ces plantules de survivre à un stress thermique normalement létal (43°C, 2 h), grâce à l’application d’un prétraitement à une température non létale (38°C, 2 h). Le pré-traitement à 38°C permet la protection du métabolisme énergétique ainsi que la reprise de la dynamique des organites lors de la phase de récupération. Au niveau transcriptionnel, les plantules pré-acclimatées surexpriment notamment des protéines chaperones et des gènes impliqués dans la photosynthèse et la régulation de l’expression des génomes mitochondriaux et plastidiaux. Au niveau protéique, l’accumulation d’HSPs et d’autres protéines de stress favorisent la récupération des plantules, tandis qu’en l’absence d’acclimatation, le choc thermique provoque la diminution des protéines ribosomales et l’accumulation de protéines impliquées dans la dégradation des protéines. Cette étude illustre l’intérêt de l’analyse multi-échelle pour décrypter les mécanismes de réponse des plantes aux stress. / In the context of climate change, the increased frequency and intensity of heat waves will likely have a negative impact on plant physiology, due to the structural destabilization of proteins and membranes caused by high temperatures. As part of this thesis, we developed and characterized an original experimental setup in which Arabidopsis thaliana seedlings are arrested in their development because of mineral starvation. These seedlings exhibit a high metabolic plasticity, especially for energy metabolism, which allows them to survive in a steady state for weeks. Then, we performed an integrative analysis of the processes that allow these seedlings to survive an otherwise lethal heat stress (43°C, 2 h), thanks to a priming treatment at a nonlethal temperature (38°C, 2 h). Priming protects the energy metabolism and permits the recovery of organelle dynamics after stress. At the transcriptional level, primed seedlings overexpress many chaperone proteins and genes involved in photosynthesis, and in the regulation of the expression of mitochondrial and plastidial genomes. At the protein level, the accumulation of HSPs and other stress proteins favour seedling recovery, whereas in the absence of acclimation, heat shock provokes the decrease of ribosomal proteins and the accumulation of proteins implicated in protein degradation. This study highlights the relevance of multi-scale analysis to decipher mechanisms of stress response in plants.

No description available.

Acute cold exposure is a significant stressor activating heat production by shivering after the prolonged exposure cellular oxidative stress increases. Chronic exposure to cold lasting at least 2 weeks leads to the development of cold acclimatization. The main thermogenic role is taken over by non-shivering thermogenesis taking place in brown adipose tissue, which significantly increases its weight due to cold. Cardiac hypertrophy, hypertension and impaired renal function are frequently observed pathologies of acclimatization at 4-5 řC. Our laboratory recently introduced a model of mild chronic cold acclimatization at 8 řC, during which no damage to the heart or kidneys occurs and has proven cardioprotective effect on reducing infarct size. Hence, the influence of this cold acclimatization model on the other cellular and molecular processes needs to be investigated. The cardioprotective effect of cold acclimatization includes changes in β-AR signaling, activation of anti-apoptotic pathways or augmentation of the antioxidant system. The aim of this thesis was to investigate the effect of cold acclimation and subsequent reacclimation on proteins regulating Ca2+ levels in the rat heart (SERCA2 and phospholamban) and on the stimulation of regulatory proteins β-arrestin 1/2 and protein kinase PDPK1. The...