O estresse calórico em gado leiteiro especializado torna-se um fator limitante para a produção de leite no estado do Rio Grande do Sul durante os meses de maior índice temperatura-umidade. O impacto fisiológico sobre o animal tem repercussão não somente sobre o metabolismo animal, mas também na quantidade e na qualidade do leite produzido. Não existem estudos prévios sobre o grau de impacto que o estresse por calor possa causar em gado da raça Holandesa no Rio Grande do Sul com enfoque no metabolismo e na qualidade do leite. O presente projeto estudou as alterações que o estresse calórico ocasiona em vacas leiteiras especializadas sobre indicadores clínicos, produtivos e metabólicos. Um total de 450 observações foram realizadas durante dois anos consecutivos em uma fazenda leiteira de alta produção da região do Planalto Médio do Rio Grande do Sul. O grau de estresse calórico foi considerado quando o índice temperatura-umidade (THI) ficou acima de 80. O estresse calórico foi evidente sobre os indicadores clínicos (temperatura corporal e frequência respiratória) e causou redução de 17% da produção de leite, bem como diminuição na quantidade de lactose e aumento na CCS, porém sem afetar o teor de gordura nem de proteína. Os indicadores metabólicos mais afetados foram proteínas totais, albumina e ureia, com respostas compatíveis com grau de desidratação leve, glicose com aumento atribuído à maior secreção de cortisol, e colesterol com aumento atribuído à menor secreção de tiroxina, em animais em estresse por calor. Lactato foi menor em animais estressados, sendo seu mecanismo objeto de futuros estudos. Ficou evidente uma condição de alcalose respiratória e a resposta compensatória de acidose metabólica. Conclui-se que o estresse calórico nos animais estudados repercute em mudanças clínicas, produtivas, metabólicas e ácido-básicas. / Heat stress is a limiting factor for milk production in high yielding dairy cows in Rio Grande do Sul (Brazil) during the months with the highest temperature-humidity index (THI). The physiological impact caused by high THI has not only consequences in the animal’s metabolism, but also in the animal’s milk yield and milk composition (quality). To our knowledge, there are no previous studies that related the impact of heat stress on metabolism and milk composition of high yielding Holstein cows in RG. The objective of the present study was to evaluate the effects of heat stress on clinical, productive, and metabolic parameters in high yielding dairy cows. A total of 450 observations were taken during 2 consecutive years in a commercial dairy farm in the RG’s plateau region. Heat stress was characterized as a THI greater than 80. Clinical parameters (rectal temperature and respiratory frequency) was clearly affected by heat stress as well as reduction of milk yield (17%), milk lactose, and increased milk somatic cells count However, milk fat and milk protein were not affected by heat stress. The metabolic parameters that were greatly affected by heat stressed Holstein cows were total protein, albumin, and blood urea concentrations corresponding to cow’s slight degree of dehydration; glucose concentration was increased and associated with a higher secretion of cortisol; and cholesterol concentration was increased due to lower secretion of tiroxine. Blood lactate concentration was lower in heat stressed animals when compared with non-stressed animals but the specific mechanism is still to be determined. Therefore, heat stressed cows evidently showed a state of respiratory alkalosis that was compensated by a state of metabolic acidosis. In conclusion, cows that experienced heat stress in the present study had altered clinical, productive, metabolic and acid-base parameters when compared with non-stressed cows.

Vários estudos indicam uma maior susceptibilidade ao estresse térmico de touros europeus quando criados em regiões tropicais, levando a efeitos deletérios à reprodução (e.g., diminuição da qualidade espermática, degeneração testicular). Tal fato pode causar expressivo prejuízo econômico visto que, nestas regiões, a estação de monta é realizada no verão. Um dos principais mecanismos propostos para explicar este efeito seria um aumento do estresse oxidativo. Assim, uma alternativa promissora seria o tratamento com antioxidantes e ácidos graxos poli-insaturados. O presente estudo tem como objetivo: Avaliar os possíveis efeitos benéficos da suplementação oral com ácidos graxos poli-insaturados (com vs. sem) e a ação protetora do tratamento sistêmico com vitamina E (com vs. sem) contra os danos oxidativos causados pelo estresse térmico testicular em touros taurinos insulados através das avaliações ultrassonográfica, morfométrica testicular (i.e, volume, temperatura, consistência, circunferência) e histológica dos testículos. Para isso, foram utilizados 16 touros Bos taurus taurus jovens (em torno de 2 anos de idade) divididos em 4 grupos (fatorial 2x2) com perfil espermático normal. Todos os animais foram submetidos à insulação testicular por um período de 96 horas. Foi realizada a ultrassonografia testicular a cada 13 dias por todo o período e mais dois meses após o período da insulação. Como controles foram avaliados os testículos dos touros antes da insulação. Concomitante à insulação, os animais foram divididos aleatoriamente em 4 lotes que foram submetidos a um arranjo fatorial 2x2, sendo um dos fatores a dieta rica em PUFA (Ácidos graxos poli-insaturados Megalac E®) todo o dia durante dois meses pós insulação. Já o tratamento sistêmico com Vitamina E (Monovin E®) foi realizado através da injeção subcutânea de 5 ml de α-tocoferol a cada 13 dias pós insulação com duração de dois meses pós insulação. Aos animais que não receberam a vitamina E, foi administrado o mesmo volume em placebo (óleo inerte). No final deste período, os animais foram castrados e os testículos utilizados para a histologia. Os resultados foram analisados através do SAS system for Windows e indicaram que tanto a suplementação oral de ácidos graxo poli-insaturados como o tratamento sistêmico com vitamina E, não alteraram as características ultrassonográficas, morfométricas e histológicas testiculares de touros de origem europeia submetidos a insulação testicular. / Several studies indicate an increased susceptibility to the heat stress in European bulls raised under tropical conditions, which leads to deleterious effects on reproduction (e.g., testicular degeneration, impaired sperm quality). This may cause significant economic losses since, in these regions, breeding season usually occurs during summer. The main mechanism proposed to explain such event is the oxidative stress. Therefore, an alternative to overcome this effect would be the treatment with antioxidant combined with a supplementation with poly-unsaturated fatty acids (PUFA). The present study aimed to evaluate the possible beneficial effect of the oral PUFA supplementation combined with a protective antioxidant treatment to overcome the deleterious effects of the heat stress on testicular echogenicity, morphometry (i.e., volume, circumference, consistency) and histology. Towards this aim, 16 young but sexually mature Bos taurus taurus (around 2 years old). All animals were submitted to testicular warming for 96 hours. Simultaneously to the insulation, animals were randomly allocated into 4 groups in a 2x2 fatorial design. One of the factors was a PUFA supplementation (supplemented vs. nonsupplemented; Megalac E®) everyday for two months. The other factor was a systemic treatment with a subcutaneous administration of 5 mL of α-tocopherol (treated vs. non treated) every 13 days for two months. Animal that did not receive the treatment were injected with 5 mL of inert oil. Testicular ultrasound evaluation was performed each 13 days from the beginning until two months after testicular warming. At the end of the period experimental period, animals were castrated and the testicles were submitted to histological evaluation. Data were statistically analyzed using the SAS system for Windows. Results indicated that oral PUFA supplementation combined with the systemic -tocopherol treatment had no influence on testicular echogenicity, morphometry and hystology in European bulls submitted to testicular warming.

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Submitted by Luis Ricardo Andrade da Silva (lrasilva@uefs.br) on 2015-12-02T20:10:10Z No. of bitstreams: 1 v.final DISSERTA??O B?RBARA PAULA DOS SANTOS BORGES DOS SANTOS BORGES.pdf: 1253496 bytes, checksum: b385afcd4779d54bd2a324ab4f1f5b5f (MD5) / Made available in DSpace on 2015-12-02T20:10:10Z (GMT). No. of bitstreams: 1 v.final DISSERTA??O B?RBARA PAULA DOS SANTOS BORGES DOS SANTOS BORGES.pdf: 1253496 bytes, checksum: b385afcd4779d54bd2a324ab4f1f5b5f (MD5) Previous issue date: 2015-08-26 / Funda??o de Amparo ? Pesquisa do Estado da Bahia - FAPEB / Vellozia sincorana Ayensu & SMITHis endemic of Rupestres Fields of Chapada Diamantina, popularly known as Candomb?. This species has a highly flammable resin, and the stem used to ignite wood stoves and roots to produce incense. Candomb? presents few studies in the literature, there are no studies of propagation of the species. This study aimed to develop in vitro multiplication protocol of V. sincorana, analyzing the behavior of in vitro shoots subjected to stress, and its influence on multiplication. They were used as explants in vitro shoots obtained, inoculated with concentrations of BAP (0.0; 2.22; 4.44 ?M), CIN (0.0; 2.32; 4.64 ?M) and IBA (0.0; 1.48 ?M) in MS ? medium supplemented with 87.64 mM sucrose, 1g.L-1activated carbon, and 0.7% agar (basic medium). Subsequently, it tested concentrations of cytokinins BAP or KIN (0.0; 5.0; 10.0; 15.0; 20.0 ?M). In experiments with thermal stress, flame shoots were exposed for different periods (0.0; 2.0; 4.0; 6.0; 8.0; 10 seconds), and the next tested whether the periods (0.0; 4.5; 6.0; 7.5; 9.0 min) exposure of the shoots 105 ? 1 ? C in sterilize. For drought stress basic medium was agar supplemented with different concentrations (7.0; 14.0; 21.0; 28.0 g) and the following experiment different sucrose concentrations (87.64; 175.28; 262. 92; 350.56 mM). The KIN showed greater efficacy in the multiplication in relation to BAP. The highest average for number of shoots and responsive% explants were in the periods 6, 8 or 10 seconds, being observed tolerance to water and thermal stress. / Vellozia sincorana AYENSU & SMITH ? end?mica dos Campos Rupestres da Chapada Diamantina, conhecida popularmente como Candomb?. Essa esp?cie possui resina altamente inflam?vel, sendo o caule utilizado para acender fog?es a lenha e as ra?zes para produzir incenso. O Candomb? apresenta poucos trabalhos na literatura, n?o havendo estudos de propaga??o da esp?cie. Esse trabalho teve como objetivo desenvolver protocolo de multiplica??o in vitro de V. sincorana, analisando o comportamento dos brotos in vitro submetidos ao estresse, e sua influ?ncia na multiplica??o. Foram utilizados como explantes brotos obtidos in vitro, inoculados em concentra??es de BAP (0,0; 2,22; 4,44 ?M), CIN (0,0; 2,32; 4,64 ?M) e AIB (0,0; 1,48 ?M) em meio MS ?suplementado com 87,64mM de sacarose, 1g.L-1 de carv?o ativado, e0,7% de ?gar (meio b?sico).No experimento seguinte, testou-se concentra??es das citocininas BAP ou CIN (0,0; 5,0; 10,0; 15,0; 20,0 ?M). Nos experimentos com estresse t?rmico, os brotos foram expostos a flambagem por diferentes per?odos (0, 2, 4, 6, 8; 10 segundos), e no seguinte testou-se os per?odos (0,0, 4,5, 6,0, 7,5; 9,0 min.) de exposi??o dos brotos a 105?1?C, em estufa. Para estresse h?drico o meio b?sico foi suplementado com diferentes concentra??es de ?gar (7,0, 14,0, 21,0, 28,0 g) e no experimento seguinte diversas concentra??es de sacarose (87,64, 175,28, 262,92; 350,56 mM).O CIN apresentou maior efic?cia na multiplica??o, em rela??o ao BAP. As maiores m?dias para n?mero de brotos e % explantes responsivos foram nos per?odos 6, 8 e 10 segundos, sendo observada toler?ncia aos estresses h?drico e t?rmico.

Orientador: João Carlos Pinheiro Ferreira / Coorientador: Elizabeth Moreira dos Santos Schmidt / Banca: Fabiana Ferreira de Souza / Banca: Gisele Zoccal Mingoti / Banca: Lindsay Unno Gimenes / Banca: Roberto Sartori Filho / Resumo: O estresse térmico reduz a eficiência reprodutiva em vacas leiteiras. O fluido folicular (FF) contém proteínas envolvidas na atividade e diferenciação celular do folículo e maturação oocitária. A caracterização das proteínas do FF pode contribuir para melhor compreensão dos mecanismos fisiológicos envolvidos na foliculogênese e comprometimento da função reprodutiva durante o estresse térmico. No primeiro experimento avaliou-se o perfil proteomico do FF de vacas em diferentes estágios do desenvolvimento folicular (pré-desvio, desvio, dominância e pré-ovulatório) e foi testada a associação das proteínas com as concentrações intrafoliculares de hormônios esteroides. Foram encontradas 22 proteínas diferentemente expressas (P < 0.05) entre as categorias foliculares, sendo o desvio um momento-chave na determinação da expressão das proteínas. Além disso, três proteínas foram correlacionadas (P < 0.05) com as concentrações intrafoliculares de estradiol, enquanto dezesseis foram correlacionadas (P < 0.05) com as concentrações locais de progesterona. A análise de vias canônicas identificou a ativação/inibição das vias associadas com a resposta de fase aguda, sistema de coagulação, sistema complemento, receptor X do fígado e retinóide e produção de óxido nítrico e espécies reativas de oxigênio. No segundo experimento, testou-se o efeito do estresse térmico sobre a expressão das proteínas do FF de vacas. Na validação do modelo experimental, foi observado que a exposição contínua ao estre... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Heat stress reduces the reproductive efficiency in dairy cows. Follicular fluid (FF) contains proteins involved in the follicle activity and cell differentiation and oocyte maturation. The characterization of the proteome of FF may contribute to a better understanding of the physiological mechanisms involved in folliculogenesis and impairment of reproductive function during heat stress. In the first experiment, the FF proteomic profile of cows at different stages of follicle development (predeviation, deviation, dominance and pre-ovulatory) was evaluated and the association of proteins with intrafollicular concentrations of steroid hormones was tested. Twenty-two differentially expressed proteins (P < 0.05) were found among the follicular categories, with deviation being a critical time-point in the determination of protein expression. In addition, three proteins were correlated (P < 0.05) with the intrafollicular concentrations of estradiol, while sixteen were correlated (P < 0.05) with the local concentrations of progesterone. The canonical pathway analysis identified the activation/inhibition of the pathways associated with acute phase response, coagulation system, complement system, liver X receptor and retinoid, and production of nitric oxide and reactive oxygen species. In the second experiment, the effect of heat stress on the expression of cow FF proteins was tested. In the experimental model validation, we observed that the continuous exposure to heat stress affected thermoregulatory mechanisms, 4 leading to a marked increase in respiratory rate, followed by an increase in rectal temperature. The influence of environmental variables from the previous day on physiological parameters and dry matter intake were more important than the immediate effect and ambient temperature represented the most determinant factor for heat exchange. Although prolonged exposures to heat stress... (Complete abstract electronic access below) / Doutor

Le contrôle de l’expression des gènes est un processus crucial pour le développement, la reproduction ou les mécanismes d’acclimatation aux stress environnementaux et met en jeu des voies de régulation post-transcriptionnelles agissant sur les ARN messagers (ARNm). Ces molécules portent des modifications chimiques dont l’une des plus abondantes est la N6-méthyladénosine ou m6A. Cette modification permet notamment d’attirer des protéines spécifiques qualifiées de « lecteurs » qui, chez les mammifères, agissent principalement pour favoriser la dégradation et/ou la traduction des ARNm. Mes travaux de thèse ont eu pour objectif de caractériser les fonctions d’un de ces lecteurs, nommé ECT2, chez la plante modèle Arabidopsis thaliana. Dans un premier temps, sa fonction de liaison aux ARNm méthylés ainsi que son rôle dans le développement de la plante ont été démontrés. Au niveau moléculaire, une approche de protéomique a permis d’identifier de nombreux partenaires d’ECT2 dont la majorité est impliquée dans le métabolisme des ARNm parmi lesquels des facteurs inhibiteurs de traduction. Les résultats d’une analyse de translatomique permettent de proposer un modèle où ECT2 jouerait un rôle de répresseur de la traduction d’ARNm en coopération avec ses partenaires LARP1 et DCP5, deux facteurs évolutivement conservés qui agissent dans le contrôle de la traduction des ARNm. Enfin, j’ai également découvert que la protéine ECT2 est dynamiquement modifiée via des phosphorylations en réponse à un stress thermique, ce qui semble notamment affecter sa capacité à reconnaitre les résidus m6A. Ces travaux suggèrent pour la première fois que l’activité d’un lecteur peut être régulée par des phosphorylations en réponse à des variations environnementales. / Control of gene expression is a crucial process for development, reproduction or acclimation to environmental stresses and involves post-transcriptional regulatory pathways acting on messenger RNAs (mRNAs). These molecules carry chemical modifications of which N6-methyladenosine (m6A) is one of the most abundant. This modification allows notably the recruitment of specific proteins qualified as “readers” which, in mammals, mostly act to promote decay and/or translation of mRNAs. My thesis aimed to characterize the functions of one of these readers, named ECT2, in the model plant Arabidopsis thaliana. First, its binding function to methylated mRNAs and its role in plant development was demonstrated. At the molecular level, a proteomic approach identified numerous ECT2’s protein partners, mainly involved in mRNA metabolism including translation inhibition factors. Results obtained from a translatome analysis suggest a model where ECT2 could play a repressive role on the translation of methylated mRNAs cooperatively with its partners LARP1 and DCP5, two evolutionarily conserved factors acting in translational control of mRNAs. Finally, I also discovered that ECT2 is dynamically modified with phosphorylations in response to heat stress affecting especially its ability to recognize m6A residues. These works suggests for the first time that the activity of an m6A reader could be regulated by phosphorylations in response to environmental changes.

Physical activity results in various types of stress in skeletal muscle including energetic, oxidative, and heat stress. Acute exposure to stress impairs skeletal muscle mitochondrial function. In contrast, chronic intermittent exposure to mild stress through exercise training results in increased mitochondrial content and respiratory capacity. While oxidative and energetic stress have received much attention regarding their long-term effect on skeletal muscle mitochondria, heat stress is not well understood. The purpose of this work was to investigate the effects of localized heat therapy on human skeletal muscle mitochondria, and to compare these effects to those of high-intensity interval exercise training. To accomplish this purpose, 35 subjects were assigned to receive 6 weeks of sham therapy, heat therapy, or exercise training; all localized to the quadriceps muscles of the right leg. Two-hour sessions of short-wave diathermy were used for the heat therapy, and identical sessions were used for sham therapy, but the diathermy units were not activated. Forty-minute sessions of single-leg extension, high-intensity interval training were used for the exercise intervention. All interventions took place three times per week. Muscle biopsies were performed at baseline, and after three and six weeks of intervention. Muscle fiber bundles were isolated and permeabilized for measurement of oxygen consumption via high-resolution respirometry. The primary finding of this work was that heat therapy improves mitochondrial respiratory capacity by 24.8 ± 6.2% compared to a 27.9 ± 8.7% improvement following exercise training. Both heat and exercise significantly increased mitochondrial respiration compared to baseline measures (p<0.05). Fatty acid oxidation and citrate synthase activity were also increased following exercise training by 29.5 ± 6.8% and 19.0 ± 7.4%, respectively (p<0.05). However, contrary to our hypothesis, heat therapy did not increase fatty acid oxidation or citrate synthase activity. Neither heat nor exercise training increased mitochondrial respiratory protein content. Overall these results suggest that heat therapy significantly improves mitochondrial function, but not to the same degree as exercise training.

The agriculture sectors in Canada are highly vulnerable to a wide range of inter-related weather risks linked to seasonal climate variability (e.g., El Ni ̃no Southern Oscillation(ENSO)), short-term extreme weather events (e.g., heatwaves), and emergent disease(e.g., grape powdery mildew). All of these weather-related risks can cause severe crop losses to agricultural crop yield and crop quality as Canada grows a wide range of farm products, and the changing weather conditions mainly drive farming practices. This dissertation presents three machine learning-based statistical models to assess the weather risks on the Canadian agriculture regions and to provide reliable risk forecasting to improve the decision-making of Canadian agricultural producers in farming practices. The first study presents a multi-scale, cluster-based Principal Component Analysis(PCA) approach to assess the potential seasonal impacts of ENSO to spring wheat and barley on agricultural census regions across the Canada prairies areas. Model prediction skills for annual wheat and barley yield have examined in multi-scale from spatial cluster approaches. The ’best’ spatial models were used to define spatial patterns of ENSO forcing on wheat and barley yields. The model comparison of our spatial model to non-spatial models shows spatial clustering and ENSO forcing have increase model performance of prediction skills in forecasting future cereal crop production. The second study presents a copula-Bayesian network approach to assess the impact of extreme high-temperature events (heatwave events) on the developments of regional crops across the Canada agricultural regions at the eco-district-scale. Relevantweather variables and heatwave variables during heatwave periods have identified and used as input variables for model learning. Both a copula-Bayesian network and Gaussian-based network modeling approach is evaluated and inter-compared. The copula approach based on ’vine copulas’ generated the most accurate predictions of heatwave occurrence as a driver of crop heat stress. The last study presents a stochastic, hybrid-Bayesian machine-learning approach to explore the complex causal relationships between weather, pathogen, and host for grape powdery mildew in an experimental farm in Quebec, Canada. This study explores a high-performance network model for daily disease risk forecast by using estimated development factors of pathogen and host from recorded daily weather variables. A fungicide strategy for disease control has presented by using the model outputs and forecasted future weather variability. The dissertation findings are beneficial to Canada’s agricultural sector. The inter-related weather risks explored by the three separate studies in multi-scales provide a better understanding of the interactions between changing weather conditions, extreme weather, and crop production. The research showcases new insights, methods, and tools for minimizing risk in agricultural decision-making / Graduate / 2021-08-19

Exposure to high heat and humidity can lead to serious health risks, including heat exhaustion and heat stroke. Wet Bulb Globe Temperature (WBGT) and heat index have historically been used to predict heat stress events, but individualized factors are not included in the measurement. It has been shown that there is a relationship between cardiovascular measurements and heat stress, which could be used to measure heat stress risk on an individual level. Research has been done to find relationships between cardiovascular metrics in a workplace environment, however the study did not include the use of a controlled environment as a baseline. This study provides measurements of transepidermal water loss (TEWL), heart rate, body core temperature, and blood pressure in a controlled environment when human subjects are exposed to high heat and humidity. Thirty subjects (n=17 females, 13 males) were asked to self-express their activity level (active vs. sedentary), gender, and age. The subjects performed a 30-minute moderate exercise routine on a stationary stepper machine in a heated environmental chamber (average WBGT of 26ºC). TEWL, heart rate, tympanic temperature, and blood pressure were recorded at every 10-minute increment of the exercise protocol per subject. The data was analyzed using JMP® software to find significant (P

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