Submitted by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2018-06-20T18:27:12Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação_Lívia Saraiva.pdf: 2509123 bytes, checksum: bb7298d31365da46681c004f463bd2f9 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2018-06-20T18:27:27Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação_Lívia Saraiva.pdf: 2509123 bytes, checksum: bb7298d31365da46681c004f463bd2f9 (MD5) / Made available in DSpace on 2018-06-20T18:27:27Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação_Lívia Saraiva.pdf: 2509123 bytes, checksum: bb7298d31365da46681c004f463bd2f9 (MD5) Previous issue date: 2018-05-21 / The leakage or release of diesel oil in soil and in hydric bodies, due to its composition by toxic compounds such as polycyclic aromatic hydrocarbons (PAH), may lead to changes in the environmental quality of the affected matrices. In this sense, bioremediation has been a well studied technique, considering the existence of many microorganisms that present a degradation capacity of such contaminants. The rhizobacterias, which have a high production capacity for biosurfactants, become a viable alternative because they are non-pathogenic microorganisms and thus safe to plants and animals. Therefore, considering that floodplain soils are regions that are subject to the petroleum derivatives contamination, and considering that rhizobacteria are species that are present in this soil type and can aid in the degradation process, the aim study proposed the determination of the individual PAH biodegradation potential of five isolates of rhizobacteria, and of the consortium of this five species, in samples of floodplain of amazon contaminated with diesel oil. For this, an experiment was carried out using the microbial suspension with 1 × 107 UFC.mL-1 of each bacterial type and the consortium in 500 g of autoclaved soil and diesel oil as carbon source. In addition, were done two samples control: (A) 500 g of autoclaved soil and diesel oil and (B) 500 g of natural soil and diesel oil. After the experiment was set up, the samples were collected for PAH determination at the times zero, 48 hours, 5, 10, 15 and 21 days. After 21 days of the experimentation, the bacteria INPA R574 and INPA 598 degraded 57.37% and 41.53%, respectively, of ΣPAH, while the others had an increase in concentration of ΣPAH. After 2 days, when the best degradation rates were observed, the specie INPA R574 was the microorganism that most stood out. In the treatment of ΣPAH, this bacterium degraded 62.15%, while, individually, it reduced the concentrations of acenaphtene, phenanthrene and benzo(a)pyrene in 86.47%, 44.65% and 79.72% respectively. In the same time, the consortium presented rates of degradation of 64.36%, higher value, however close to the individual rate of INPA R574. The INPA R548 microorganism did not significantly contribute to the degradation of any of the contaminants studied, as well as ΣPAH. The control sample (A) showed relevant degradation rates, suggesting the nutrients added to the control favored the growth of native soil bacteria that were able to degrade the PAH of the diesel added to the samples. / O vazamento ou derramamento de óleo diesel em solo e corpos hídricos, devido sua composição por compostos tóxicos como os hidrocarbonetos policíclicos aromático (HPA), pode levar à alteração da qualidade ambiental das matrizes atingidas. Nesse sentido a biorremediação tem sido uma técnica bastante estudada, considerando a existência de muitos microrganismos que apresentam eficiência na degradação de tais contaminantes. As rizobactérias, que possuem alto poder de produção de biossurfactantes, tornam-se uma alternativa viável por serem microrganismos não patogênicos e, assim, seguros a plantas e animais. Diante disso, considerando que os solos de várzea são regiões sujeitas à contaminação por derivados de petróleo e considerando que as rizobactérias são espécies que estão presentes nesse tipo de solo e podem auxiliar no processo de degradação, o presente estudo propôs-se a determinar o potencial individual de biodegradação de HPA de cinco isolados de rizobactérias e do consórcio das cinco espécies em amostras de solo de várzea da Amazônia contaminado com óleo diesel. Para isso, foi realizado um experimento utilizando suspensão microbiana com 1 × 107 UFC.mL-1 de cada espécie e do consórcio entre elas, em 500 g de solo autoclavado e óleo diesel como fonte de carbono. Além disso, foram feitas duas amostras controle: (A) 500 g de solo autoclavado e óleo diesel e (B) 500 g de solo natural e óleo diesel. Após a montagem do experimento foram realizadas coletas para determinação dos HPA nos tempos 0, 2, 5, 10, 15 e 21 dias. Após os 21 dias do experimento, as bactérias INPA R574 e INPA R598 degradaram 57,37% e 41,53%, respectivamente, do ΣHPA, enquanto as demais apresentaram aumento na concentração do ΣHPA. Após 2 dias, onde observaram-se as melhores taxas de degradação, a espécie INPA R574 foi o microrganismo que mais se destacou. Em se tratando do ΣHPA, essa bactéria degradou 62,15%, enquanto que, de maneira individual, reduziu as concentrações de acenafteno, fenantreno e benzo(a)pireno em 86,47%, 44,65% e 79,72%, respectivamente. No mesmo tempo, o consórcio apresentou taxa de 64,36%, valor superior, no entanto bem próximo à taxa individual da espécie INPA R574. O microrganismo INPA R548 foi o que não contribuiu de maneira significativa para a degradação de nenhum dos contaminantes estudados, bem como do ΣHPA. A amostra controle A apresentou taxas de degradação relevantes, sugerindo que os nutrientes adicionados ao controle favoreceram o crescimento de bactérias nativas do solo que foram capazes de degradar os HPA do diesel adicionado às amostras.

Made available in DSpace on 2014-06-12T22:57:19Z (GMT). No. of bitstreams: 2 arquivo1351_1.pdf: 1227406 bytes, checksum: fac5ecb507b7a122f0c7ed3b520c9231 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2008 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / As áreas costeiras sofrem com a grande quantidade de poluentes que chegam pelos rios. Esses poluentes, por sua vez, tendem a se acumular no sedimento, que desta forma tornamse tóxico tanto para os organismos que o utilizam como habitat quanto para os que dependem deste ambiente para sua alimentação. Os poluentes podem tornar-se disponíveis para a coluna d água através de processos como dragagens. Desta forma, o presente estudo traz uma série de testes utilizando o copépodo bentônico Tisbe biminiensis para a sua avaliação e implementação como organismo-teste em ensaios toxicológicos utilizando sedimento. Como análises preliminares, foram realizados testes utilizando sedimento coletado no estuário do rio Maracaípe para confirmar sua condição de controle. O dicromato de potássio (K2Cr2O7) foi utilizado como substância de referência para determinação da variação de sensibilidade do T. biminiensis através da análise da variação da CL50. Testes com diferentes tamanhos de grãos foram realizados com o objetivo de saber se existia alguma preferência desta espécie a alguma faixa de tamanho específico. Posteriormente, ensaios toxicológicos utilizando o sedimento da Baía de Suape em dois períodos (seco e chuvoso) do ano de 2003 foram realizados para avaliar a sua toxicidade. No período de abril de 2005 a janeiro de 2006, a avaliação toxicológica do Porto de Suape foi expandida para o estuário do rio Ipojuca, aumentando também o número de coletas (2 no período chuvoso e 2 no seco). Por último, foram realizadas coletas de sedimento no estuário do rio São Paulo (Bahia, Brasil) um local com histórico de contaminação por hidrocarbonetos. Estas amostras de sedimento foram testadas em bioensaios cujo objetivo foi a comparação da sensibilidade do copépodo T. biminiensis e de pós-larvas (PLs) de Litopenaeus vannamei. Como resultados, tivemos que o sedimento do estuário do rio Maracaípe não interfere na sobrevivência ou reprodução do T. biminiensis. A CL50-96h do K2Cr2O7 foi de 9,45 mg.L-1 e para o Cr foi de 3,19 mg.L-1. O T. biminiensis não demonstrou preferência quanto ao tamanho do grão. No primeiro ano de coleta no Porto de Suape, observou-se uma mortalidade significativamente superior em relação ao controle no ponto 4 no período seco, porém não foi observado efeito letal ou subletal no período chuvoso. Correlações significativas foram observadas entre a toxicidade letal e os Σn-alcanos e Σ(C21-C34). No segundo ano de coleta no Porto de Suape e no estuário do rio Ipojuca, não foi observado efeito letal em nenhum ponto de coleta ou período amostrado, porém, efeitos subletais ocorreram em diferentes períodos e pontos de coleta. Maior toxicidade foi observada no mês de julho/agosto (2005), onde ocorreram efeitos subletais em todos os pontos. No estuário do rio São Paulo, não foi observado efeito letal em nenhuma das espécies utilizadas. Porém, efeitos subletais foram observados quando o copépodo foi utilizado, indicando presença de contaminantes no estuário do rio São Paulo em três pontos no mês de março e em apenas um no mês de outubro. Não foi observado qualquer efeito subletal quando utilizamos a PL do camarão em nenhum dos pontos ou meses de coleta. Análises de correlação de Pearson identificaram correlações significativas entre os efeitos subletais observados com o copépodo e os HRP, HTP e MCNR. Ao longo do trabalho as concentrações de metais pesados, HPAs e alifáticos são discutidos. De acordo com este estudo podemos concluir que à área estuarina de Suape, pode ser considerada como uma área com baixo potencial para causar efeitos tóxicos letal. Com relação ao estuário do rio São Paulo, apesar de ser uma área onde observa-se grande quantidade de óleo exudando do solo, é uma área com baixa probabilidade de causar efeito tóxico letal, porém, percebe-se uma variação espacial relevante, pois em um dos pontos, 2 amostras apresentaram mortalidade superior a 80% e a outra, inferior a 10%, daí a importância da realização de réplicas amostrais em campo. Com relação a utilização do copépodo T. biminiensis, podemos concluir que é um organismo promissor para ser utilizado em testes de toxicidade com sedimento, pois é uma espécie generalista quanto a granulometria do sedimento, apresenta uma constância na sua sensibilidade quanto a substância de referência e apresentou-se mais sensível do que as PLs do L. vannamei

Made available in DSpace on 2014-06-12T23:16:10Z (GMT). No. of bitstreams: 2 arquivo951_1.pdf: 2926833 bytes, checksum: 77c51212a36f0c4105a9cb1a7758188f (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2011 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Os contaminantes emergentes tem sido um assunto largamente discutido na comunidade cientifica, principalmente quando relacionado à poluição em ambientes aquáticos. Esses poluentes abrangem fármacos, cosméticos, surfactantes, aditivos para a gasolina, compostos orgânicos fluorados, corantes, hidrocarbonetos poliaromáticos, entre outros. Estes compostos, em sua maioria, são dificilmente detectados e geralmente não são degradados pelos métodos convencionais de tratamento (processos biológicos), sendo assim, mesmo após passagem pelas estações de tratamento, continuam livres no meio, podendo atingir as águas para abastecimento humano. O objetivo deste trabalho foi detectar o contaminante emergente cloridrato de histamina em solução aquosa por potenciometia direta utilizando eletrodo íon-seletivo e degradar os contaminantes HIDROCARBONETOS POLICÍCLICOS AROMÁTICOS de petróleo solubilizados em solução salina utilizando processos oxidativos avançados. Através de testes de seletividade foi possível desenvolver uma metodologia potenciométrica, utilizando um eletrodo tubular sem placa de cobre e na preparação da membrana sensora, PVC (30,4%), 2-fluorofenil 2-nitrofenil éter (68,3%), tetrakis (4- clorofenil) borato de potássio (6,4 x 10-3 mol.kg-1) e-ciclodestrina (1%). O eletrodo utilizado apresentou tempo de vida útil de 10 meses sem qualquer procedimento de condicionamento especial. O coeficiente de seletividade que mostra o acompanhamento da interferência causado por outras espécies com concentrações diferentes, apontou valores inferiores a 0,25 x 10-5 mol.L- nas condições testadas. Nesta etapa do trabalho os eletrodos íon-seletivo mostraram ter características de desempenho adequadas para o monitoramento do cloridrato de histamina em solução aquosa, alem de ser bastante versáteis em sua construção e detecção do composto proposto, permitindo assim em um futuro próximo, diversas aplicações na área ambiental. Na degradação dos hidrocarbonetos policíclicos aromáticosS (HPA) da fração solúvel do petróleo (FSA) por fotólise e processos oxidativos avançados (POA), pode-se avaliar qual o processo de maior eficiência e a melhor fonte de radiação. No processo de fotolise (UV-C) a taxa de degradação dos hidrocarbonetos poliaromaticos (HPA) do petróleo bruto foi de 89,98% ajustando o sistema em pH 5 e utilizando um tempo reacional de 4h. Com o processo Fenton o percentual de degradação dos (HPA) obtido foi de 80,86%, a partir de uma concentração de peróxido de hidrogênio igual a 0,8 mol, com o pH do sistema igual a 5 e tempo reacional. E na avaliação das fontes de radiação (luz negra, branca, UV-C e solar) do processo foto-Fenton, o melhor resultado 90,89% obteve-se utilizando luz solar, partindo da menor concentração de peróxido de hidrogênio (0,4 mol.L-1), maior tempo de exposição a radiação (6h) e com pH do sistema igual a 4. Associado a taxa de degradação, este processo apresenta baixo custo operacional

Glucocorticoid excess is associated with adverse effects on a number of physiological parameters, leading to obesity, dysfunction of the hypothalamic-pituitary- adrenal (HPA) axis and behavioural changes such as anxiety and impaired learning and memory. Circulating and local tissue glucocorticoid levels are tightly controlled by the HPA axis but an additional level of control exists in tissues such as brain, liver and adipose tissue. In these structures, enzymes including 5α-reductase 1 (5αR1), catalyse the conversion of corticosterone to A-ring reduced metabolites, which have a different spectrum of activities. This thesis investigates the role of 5αR1 in regulating central glucocorticoid actions which control HPA axis function and behaviour in a mouse model with genetic disruption of 5αR1 (5αR1-KO). Preliminary data showed 5αR1-KO mice were susceptible to developing insulin resistance and obesity and had reduced HPA axis responses to acute stress. Additionally, male 5αR1-KO mice were more prone to obesity than wild-type (WT) when fed a high-fat diet whilst female 5αR1-KO mice gained more weight than WT even on a normal chow diet. Intriguingly, female 5αR1-KO mice subjected to social isolation stress lost this extra weight and became comparable to WT controls. This study tested the hypothesis that 5αR1-KO mice are less able to inactivate glucocorticoids in the periphery and within tissues, resulting in a predisposition to metabolic disturbances and behavioural alterations. These were hypothesised to include hyperphagia, weight gain, impaired stress responses, anxiety (exacerbated by environmental stress) and cognitive deficits. It was also thought that many of these features would be more pronounced in female vs. male mice. The main aims of this study were to determine if 5αR1-KO induced weight gain and if this was correlated to altered gene expression of key hypothalamic neuropeptides which regulate appetite, to determine the central mechanisms which underpin attenuated HPA axis responses to acute stress and to determine whether behaviours such as anxiety and learning and memory ability are affected by global 5αR1 loss. It was hypothesised that female 5αR1-KO mice have increased appetite and reduced locomotor activity compared with WT and male 5αR1-KOs. However, male 5αR1- KO mice (on a mixed genetic background, C57Bl/6j/SvEv/129) were hyperphagic on a normal chow diet but did not gain extra weight, while female 5αR1-KO mice gained more weight vs. WT despite hypophagia. Free ambulatory activity was unaffected by genotype in either sex. Male 5αR1-KO mice appeared less anxious but responses of female 5αR1-KO mice in tests of anxiety did not differ from WT controls. Mice lacking 5αR1 generally had a poorer metabolic profile with impaired glucose tolerance and hyperinsulinaemia; with hepatic steatosis evident in female mice. There was evidence of compensatory changes in hypothalamic orexigenic and anorexigenic peptides. Phenotypes were sexually dimorphic such that male mice had a poorer metabolic profile vs. females, which was particularly marked in male 5αR1- KO animals. 5αR1-KO mice were previously shown to have attenuated HPA axis responses to acute stress and it was hypothesised that disruption of 5αR1 would result in altered expression of genes related HPA axis regulation with a view to increased negative feedback. Here, male and female 5αR1-KO mice demonstrated altered corticosteroid receptor expression within the hippocampus and the pituitary, two key structures in the HPA cascade. In situ hybridisation showed reduced mRNA for MR in the hippocampus and for Crh in the hypothalamus of 5αR1-KO mice. These modifications along with decreased Crhr-1 mRNA (CRH‘s main receptor) may be due to a lack of corticosterone metabolism within the brain resulting in enhanced negative feedback and reduced HPA axial drive. In order to study behaviour in detail and also to test whether potential central glucocorticoid excess may predispose to cognitive decline with ageing, a separate cohort of female 5αR1-KO backcrossed onto a uniform C57Bl/6j background was studied both when young (6 months) and when aged (14-15 months). Additionally, mice were housed in either groups or singly (social isolation) to investigate the potentially additive effects of environmental stress. It was hypothesised that local glucocorticoid increases in the brains of 5αR1-KO mice would be associated with anxiety and cognitive deficiencies and that these phenotypes would be exaggerated by the stress of social isolation as well as ageing. Behavioural differences were not observed at 6 months of age. However aged, 5αR1-KO mice housed singly showed increased anxiety and had higher plasma corticosterone levels than group-housed mice. Moreover, aged mice lacking 5αR1 performed less well than WT in tests of memory and had a marginally greater cognitive decline when learning ability at 14- 15 months old was compared to that of the same animals tested at 6 months old. Overall, mice with global 5αR1 loss appeared susceptible to anxiety as well as some degree of age-associated cognitive impairment, but only when subjected to social isolation stress which is a known chronic stressor. The final set of experiments aimed to determine the effect of mouse strain on 5αR1- KO phenotypes. It was hypothesised that glucocorticoid clearance would be attenuated to a lesser degree in 5αR1-KO mice bred onto a congenic C57Bl/6j strain compared to those of the mixed strain and that this would manifest as less disruption of metabolism and less suppression of HPA axis stress responses. Although social isolation again induced weight-loss in female mice and more so in 5αR1-KO animals, mice on the C57Bl/6j background strain did not show dampened HPA axis responses to acute stress as seen previously. It was subsequently shown in adrenalectomised mice that animals bred on the C57Bl/6j strain cleared active corticosterone from plasma and liver faster than mixed strain mice. This may have rendered mixed strain 5αR1-KO mice more susceptible to excessive corticosterone levels producing a more exaggerated phenotype in this group. In conclusion, these data suggest a role for the enzyme 5αR1 in modifying glucocorticoid concentrations in the brain and liver, influencing not only metabolic and peripheral effects such as weight gain and insulin resistance, but also in modifying cognition, appetite stimulation and affective behaviours. It has been highlighted that outside factors such as housing and age can modify these phenotypes and are important considerations for future studies. This study has also highlighted the importance of choosing an appropriate genetic background for genetically modified animals since phenotypes can be enhanced or attenuated depending on strain. Finally, 5αR inhibitors are used to treat disorders such as benign prostatic hyperplasia in men, and it is important to consider that these drugs may have a wide array of associated side effects both systemically and in the central nervous system.

The mesocorticolimbic system is involved in fundamental processes that drive motivational behaviors essential for survival (feeding, reproduction and sexual behavior, etc.), as well as neurochemical activity involved in mood regulation. Stressful life events are an important cause of dysregulated psychological functioning, which in some leads to a pathophysiology of mood disorders. A source of such disorder could be, among other underlying factors, an impairment of synaptic plasticity induced by alterations in the levels of neurotrophins and/or aberrant glucocorticoid responses. The role of the brain derived neurotrophic factor (BDNF) and its high affinity receptor tyrosine-related kinase B (TrkB) in the mesocorticolimbic reward circuitry has been largely studied in adulthood, yet a possible role of this system in mediating memory and emotional responses induced by stress during the juvenile, adolescence period has not been elucidated. The proposed set of thesis studies are designed to investigate the roles of BDNF and TrkB signaling, via the selective and non-competitive TrkB antagonist, ANA-12 (N-[2-[[(Hexahydro-2-oxo-1H-azepin-3-yl)amino]carbonyl]phenyl] benzo[b]thiophene-2-carboxamide), in the expression of stress-induced changes in the brain stress circuitry (including the medial prefrontal cortex (mPFC), hypothalamic-pituitary-adrenal (HPA) axis, and hippocampus) and reward signaling systems of the brain (including the nucleus accumbens (NAc) and ventral tegmental area (VTA)). In addition, experiments aim to determine behavioral changes following stress exposure in male and female Wistar rats. Finally, the possible interplay between BDNF, dopamine, glutamate and orexins in response to repeated stress is examined. Articles 1 and 2, aimed to assess the biochemical and behavioral effects of direct ANA-12 infusion (0.25 µg/ 0.5µl) into the nucleus accumbens shell during exposure to a 10-day heterotypic stress paradigm in male rats. Specifically, Article 1 demonstrated a key role for BDNF/TrkB signaling to regulate stress-induced effects. Notably, the impact of ANA-12 to attenuate anxiety-like behavior in repeatedly stressed rats while increasing anxiety behavior in non-stress rats suggest an interesting behavioral and neurochemical state-dependent process induced by TrkB receptor signaling. Article 2 supports the key role for BDNF secretion in basal and stress-induced behaviors in rats suggesting an influence of TrkB in sociability, motivation and passive avoidance. Furthermore, this role of TrkB extended to increased expression of orexin A in the Perifornical area (PfA) and a decrease in the ventral CA1 of the hippocampus, and in stress-induced elevations in orexinergic projections to the VTA, of which reductions were observed in non-stress groups treated with ANA-12. Article 3 demonstrated gender-specific behavioral and biochemical responses in different developmental periods and the impact of TrkB activation, dependent on stress exposure, to affect the regulation of TrkB receptor isoforms (full length and truncated TrkB, TrkB.FL and TrkB.T1, respectively) in adulthood. Results revealed increased CORT responses in adolescent females relative to males and attenuated CORT secretions in both genders by TrkB inhibition. Elevated activity levels in young adult females and increased passive coping behavior in the forced swim in stress-naïve females were also noted, in addition to novel observations on brain region and sex differences in TrkB receptor isoforms. Taken together, thesis findings derived from applications of ANA-12, shall foster knowledge on the contribution of BDNF in regulation of mood upon stress exposure at times when the brain is undergoing important maturation and remodelling, as well as on the relationship of stress exposure during adolescence and lasting brain and behavioral disorders in adulthood.

Une grande diversité dans la réponse adaptative au stress est observée entre les individus favorisant une sensibilité variable face aux stresseurs et pouvant conduire à une vulnérabilité à développer divers troubles et pathologies. Cette diversité est sous tendue par les caractéristiques propres de chaque individu, déterminées par le patrimoine génétique en interaction avec les facteurs environnementaux. Des études génétiques menées au laboratoire ont permis de placer le gène de la Cbg comme un candidat important influençant les réponses de stress. L’équipe a alors développé un modèle de souris déficiente pour le gène Cbg (k.o. total). La CBG est une glycoprotéine plasmatique responsable de la biodisponibilité et du transport jusqu’à leur cible des glucocorticoïdes, produits finaux de l’axe corticotrope. A l’aide de ce modèle original, l’objectif de mon travail de thèse a été d’étudier les conséquences fonctionnelles de la déficience en CBG sur les réponses de stress. Nous avons ainsi analysé l’activité et la réactivité de l’axe corticotrope ainsi que les comportements émotionnels des mâles et des femelles k.o. Cbg dans des conditions de repos, de stress aigu et dans un contexte mimant l’effet d’un style de vie occidentale (modélisé par une alimentation enrichie en gras, associée à un stress chronique). Nous présentons ainsi un modèle murin unique d’hypo-réponse des glucocorticoïdes au stress associé à une réponse comportementale adaptative ralentie au niveau émotionnel et cognitif. L’ensemble de ces travaux contribue à placer la CBG et son gène comme acteur majeur de la variabilité individuelle des réponses de stress. / A great diversity in the adaptive response to stress is observed between individuals favoring a variable sensitivity to face stressors and leading to a vulnerability to develop various disorders and diseases. This diversity is due to the characteristics of each individual, as determined by the genetic background in interaction with environmental factors. Genetic studies conducted in the laboratory demonstrated that the Cbg gene is an important candidate influencing stress responses. The team then developed a mouse model deficient for the gene Cbg (total k.o.). CBG is a plasma glycoprotein responsible for the bioavailability and the transport of glucocorticoids, the final products of the HPA axis, to their target.Using this original model, the objective of my thesis was to study the functional consequences of CBG deficiency on responses to stress exposure. We have analyzed the activity and reactivity of the HPA axis and the emotional behaviors of males and females k.o. Cbg in resting conditions, acute stress and in a context that mimics the effect of a Western life style (modeled by a high fat diet, associated with chronic stress). We present an unique mouse model of glucocorticoid hyposignaling in response to stress associated with behavioral responses slowed down at the emotional and cognitive levels. Overall, this work contributes to place CBG and its gene as major actor of individual variability to stress.

Det är känt att humant trombocytantigen (HPA) kan innebära komplikationer vid transfusion av trombocyter. Om en patient erhåller trombocyter med humant trombocytantigen som personen redan utvecklat antikroppar emot kan komplikationer som feber, påskyndad nedbrytning av trombocyter som ger trombocytopeni samt post-transfusion purpura uppstå eftersom immunförsvaret då ser trombocyterna som fientliga. Från den 14:e veckan under graviditeten kan alloantikroppar från modern passera placentabarriären över till fostret. Om humant trombocytantigen skiljer mellan moder och foster kan modern utveckla antikroppar. Dessa antikroppar kan då förstöra fostrets trombocyter. Detta leder till en lägre koncentration av trombocyter hos barnet. I värsta fall kan detta leda till hjärnblödning med dödlighet på ca.20%. Om barnet överlever födseln kommer denne födas med fetal/neonatal alloimmuniserad trombocytopeni (FNAIT), d.v.s. medfödd trombocytopeni. Målet med denna studie var att utveckla en multiplex PCR-screen, snabbt positivt/negativt svar för högfrekventa Humant trombocytantigen alleler baserat på de mest frekventa som förekommer i dansk befolkning: HPA 1a, -2a, -3a, -5a, -15a och -15b med Extract-N-AmpTMblood kit. Negativa prov från screening genomgick allelic discrimination real-tids PCR för konfirmering av sann HPA- genotyp. En lyckad multiplex screenmix innehållande HPA 1a, -2a, -5a samt -15a genomfördes. Då HPA - 3a bildade ospecifika band fick denna plockas bort ur mixen. För HPA 15b bildades ingen PCR- produkt och kunde därför inte inkluderas. Totalt screenades 44 blodgivare från Region Skåne varav fyra var negativa för 15a. Detta konfirmerades med allelic discrimination där dessa genotypades till 15b och i likhet med den multipla screeningen inte visade amplifiering av 15a. Vidare optimering krävs där nya primers för 3a samt 15b måste designas för att skapa en komplett högfrekvent human trombocytantigen screen.

Chronic stress exposure is hypothesized to increase the risk for developing a mental or physical disease, which can be summarized as an overall increased vulnerability to adverse health conditions. This thesis shows one potential pathway of stress exposure entering the body via activation of the hypothalamus pituitary adrenal (HPA) axis and the interaction between HPA axis and immune activation. Chronic stress caused by work overload or the experience of stressful life events was associated with altered levels of cortisol, the main effector hormone of the HPA axis. Further, chronic stress was shown to effect the distribution of neutrophils, a leukocyte subtype known for its defence properties as well as for its side effects of tissue damage. Additional analyses support a theory that HPA axis and immune cells work in synergy to adapt the organism to chronic stress exposure and therefore represent one pathway how stress can cause altered immune defence toward an increased vulnerability to disease.

Purpose: Moderate-intensity aerobic exercise (MAE) has been shown to elicit improvements in cognition and subsequent academic performance among preadolescents. Aerobic exercise has also shown to increase cortisol release in response to increasing exercise intensity. However, it is unknown if increased cortisol levels following exercise are related to acute improvements in executive function following a bout of MAE in preadolescents. The purpose of this study was to examine the potential effects of increased cortisol release after acute MAE on attention and working memory among preadolescents. Methods: Eleven preadolescents [6 males, 5 females] volunteered to participate in this study (age=9.45±1.03). Participants were randomized in a counterbalanced fashion to 30 minutes of rest or 30 minutes of treadmill MAE (60-70% HR max). Immediately pre-post each condition, participants completed a cognitive battery consisting of tests of attention (Flanker Test) and working memory (List Sorting Working Memory Test), as well as salivary samples for the analysis of cortisol. Linear Regression models were used to assess significance of covariates. Generalized linear models were used to assess significance of changes in each dependent variable against time, condition, time*condition and change in cortisol. Tukey’s HSD post-hoc tests for multiple comparisons were used to assess the effect of condition on working memory, attention, and salivary cortisol. Results: There was a significant effect of condition on working memory (F=3.16, p =0.04), with no change from pre-post rest (p=0.93) and improving from pre-post exercise (p=0.04). There was no effect of condition on attention or salivary cortisol, most likely due to a small sample size. Multiple linear regression models showed a significant effect of age (p=0.03) and change in cortisol (p=0.007) on working memory. Conclusion: Exercise had a positive effect on working memory, however, we were unable to relate this improvement to changes in salivary cortisol due to a lack of statistical power. This study could provide insight into the physiological effects of increased cortisol release on cognition, specifically in regard to working memory. However, more data are needed to achieve sufficient statistical power to detect these relationships.

Animal personality is a fairly new branch of biology and has been defined as a difference in behaviour between individuals that is relatively consistent across time and/or context. What researchers now are interested in is to find out what it is that creates and maintains this relatively consistent difference between individuals. One possibility is the stress hormone, corticosterone. I have in this report summed up some of the available studies regarding animal personality and its possible correlation to corticosterone. The personality traits that have been reviewed in this report are boldness, exploration, activity, aggressiveness and sociability. The result of these studies show that boldness have both a negative and a positive correlation; exploration showed different correlations between studies; aggressiveness showed different correlation between different animal types and sociability showed both a negative and none correlations. The only one that I could not determent the correlation for was activity. The research regarding animal personality and corticosterone can be of use when looking at animal welfare and how stress affects different individuals. This can give us a direction in our work to reduce stress for animals in research facilities and food production.