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Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Isolated populations of northern bobwhites (Colinus virginianus) have declined causing many quail managers to attempt population restoration by releasing captive-reared bobwhites or translocating wild bobwhites. I evaluated three restoration techniques: (1) release of captive-reared bobwhites, (2) translocation of bobwhites from high densities to low densities, and (3) release of captive-reared and translocated bobwhites acclimated on site prior to release. These results show that captive-reared birds have reduced survival and fewer nesting attempts when compared to translocated birds and that acclimation time was not a factor. I hypothesized that high mortality rates were caused by captive-reared birds exhibiting different predator avoidance behavior than wild birds. Captive-reared and wild-trapped bobwhites were subjected to independent predator simulations and their responses were recorded on high definition video. Threat recognition time, reaction type, and reaction time was recorded for comparative analysis. Pen-reared birds recognized the simulated raptorial and terrestrial predator threats quicker than wild-trapped birds, but reaction times were not different among groups. However, the type of reaction was different among groups where pen-reared birds typically flushed immediately upon recognizing either simulated predator as compared to wild-trapped birds which typically ran or held when subjected to the raptorial threat and showed little to no observable reaction to the terrestrial threat. These results reveal a potential loss of a holding trait in pen-reared birds, resulting in a quicker revealing of their position in the presence of a threat, thereby increasing their risk of predation.

Pharmaceuticals are group of organic substances with significant worldwide consumption in human and veterinary medicine. These compounds may be metabolized in the organism, but in some cases they remain unchanged and both are usually excreted via renal excretion in the native form or as metabolites. Large quantities of pharmaceuticals and their metabolites contaminate municipal wastewater. The wastewater treatment plants are unable to remove these substances completely, so they contaminate surface water, groundwater and soil as well. Due to the biological activity of pharmaceuticals, long - term effect may cause bacterial resistance, endocrine influence, DNA and renal damages in non-target organisms. The phytoextraction and the translocation of radiolabeled diclofenac with 125 I were experimentally studied by using of in vitro cultivated plants Helianthus annuus and Zea mays. Efficiency od phytoextraction was monitored as decrease of radioactivity of tested substance [125 I]diclofenac in Murashige-Skoog cultivation medium. Both species are able to extract tested substance during 8 to 10 days of cultivation, with efficiency approximately 85 % using Zea mays and 79 % using Helianthus annuus. Better extraction ability of diclofenac was observed at Helianthus annuus - 80 mg/ kg of dry weight compared...

The mitochondrial control region (MCR) has played an important role as a population genetic marker in many taxa but sequencing of complete eukaryotic genomes has revealed that nuclear integrations of mitochondrial DNA (numts) are abundant and widespread across many taxa. If left undetected, numts can inflate mitochondrial diversity and mislead interpretation of phylogenetic relationships. Comparative analyses of complete genomes in humans, orangutans and chimpanzees, and preliminary studies in gorillas have revealed high numt prevalence in great apes, but rigorous comparative analyses across taxa have been lacking. The present study aimed to systematically compare the evolutionary dynamics of MCR numts in great apes. Firstly, an inventory numts derived from the region containing the MCR subdomains was carried out by genomic BLAST searches. Secondly, presence/absence of each candidate numt was determined in great ape taxa to estimate numt insertion rate. Thirdly, alternative mechanisms of numt insertion, either through direct mitochondrial integration or post-insertional duplications, were also assessed. Fourthly, the effect of nuclear and mitochondrial environment on patterns of nucleotide composition and substitution was assessed through sequence comparisons of nuclear and mitochondrial paralogous sequences. Finally, numts in the gorilla genome were identified through two experimental methods and their use as polymorphic genetic markers was then evaluated in a sample of captive gorillas from U.S. zoos. A deficit of MCR numts covering two particular mitochondrial subdomains was detected in all three apes examined, and is largely attributed to rapid loss of mitochondrial and nuclear sequence identity in the mitochondrial genome. Insertion rates have varied during the great ape evolution and exhibit substantial differences even between related taxa. The most likely mechanism of numt insertion is direct mitochondrial integration through Non-Homologous-End-Joining Repair. Transition/transversion ratios differed significantly between both mitochondrial and nuclear sequences and between numts from coding and non-coding mitochondrial regions. A previously documented upward bias in the GC content of the primate mitochondrial genome was confirmed and the extent of this bias relative to the corresponding numt sequences increased with numt age. Five gorilla-specific numts were isolated, including three exhibiting insertional polymorphisms that will be used in future population genetic studies in free-range gorilla.

In this study, we sought to define an underlying molecular mechanism of how inflammation induces cancer initiation. Cancer-associated inflammation is marked by the presence of inflammatory cells and mediators including cytokines, chemokines, and reactive oxygen species. There is a growing body of evidence establishing the link between chronic inflammation and cancer. Twenty percent of cancers have been linked to chronic infections. For instance, bacterial and viral infections induce inflammation which is a known risk factor for cancer. During inflammation, Ml macrophages' production of pro-inflammatory cytokines and reactive oxygen species (ROS) drives their function as anti-microbial. Likewise, the transcription factor nuclear factor kappa B (NF-KB) is known to induce a variety of stimulators, including ROS, to contribute to the inflammatory process. Therefore, we sought to explore the relationship between Ml macrophages and NF-KB, suggesting that Ml macrophage mediates cancer initiation via a NF-KB-dependent pathway, which collectively contributes to a metastatic phenotype.

Student Number : 9906751K - MSc dissertation - School of Molecular and Cell Biology - Faculty of Science / In addition to its crucial role in cell adhesion, β-catenin is also known to augment gene expression by forming a complex with lymphoid enhancer factor/T-cell factor in the nucleus. Unregulated β-catenin expression and/or its increased nuclear presence can lead to abnormal cell proliferation, tumour invasion and metastasis. Pertinent is the fact that the actin cytoskeleton is central to the translocation of several nuclear proteins. This study investigated whether the actin cytoskeleton influences the nuclear translocation of β-catenin in human oesophageal squamous cell carcinoma (HOSCC), a metastatic disease of common occurrence in South Africa. Disruption of the actin cytoskeleton of five moderately differentiated HOSCC cell lines, with cytochalasin D (cytoD), showed that the nuclear β-catenin level was unaltered in SNO, WHCO1 and WHCO5, but decreased in WHCO3 and WHCO6. CytoD treatment did not affect the cytoplasmic/membrane β-catenin level in these cell lines. Further examination of the possible association between the actin cytoskeleton and nuclear β-catenin translocation, required the design and stable transfection, of a vector containing full-length human β-catenin cDNA into one of the HOSCC lines. Stimulation of exogenous β-catenin expression in transfected WHCO1 cells did not increase cellular β-catenin level, nor did the stimulation of endogenous β-catenin expression with DMSO. In most cases (SNO, WHCO1 and WHCO5) the nuclear distribution of β-catenin in HOSCC is independent of a functional actin cytoskeleton, nonetheless there are some exceptions (WHCO3 and WHCO6). The observed variation within the HOSCC lines is possibly due to specific underlying event/s particular to the cell line. The stable level of β-catenin expression could be a consequence of regulatory pathways in WHCO1 compensating for the induced imbalance of β-catenin expression.

A translocação recíproca é o rearranjo equilibrado mais comum em humanos. Frequentemente, indivíduos com rearranjos equilibrados não apresentam manifestações clínicas, entretanto, na meiose, o pareamento entre cromossomos translocados forma uma figura quadrivalente em forma de cruz que torna a disjunção cromossômica incerta e dependendo do rearranjo, o individuo pode vir a ser infértil, apresentar um risco aumentado de abortamento espontâneo e/ou da prole apresentar alterações fenotípicas. Neste projeto, investigamos duas famílias de pacientes inférteis, portadores de translocações cromossômicas. O objetivo foi caracterizar as alterações citogenéticas e citogenômicas relacionadas à infertilidade masculina em pacientes portadores de rearranjos aparentemente equilibrados, associando técnicas de citogenética clássica (bandeamento GTG), citogenética molecular (FISH) e citogenômica (array-CGH). Foram estudados sete indivíduos da família 1, sendo diagnosticados três portadores da translocação (X;22), sendo um deles azoospérmico. Nesta família foram ainda detectados dois casos de mosaicismo para síndrome de Turner. A família 2 foi composta por dois irmãos oligozoospérmicos, portadores de translocação (8;13). Com a aplicação da técnica de FISH, definimos o cariótipo final dos portadores dos rearranjos como 46,XX ou 46,XY,t(X;22)(p22.3;q11.2) para a família 1 e 46,XY,t(8;13)(q13;q14)para a família 2. A técnica de array-CGH (plataforma 2x400K, Agilent) detectou alterações no número de cópias de alguns genes candidatos relacionados ao fenótipo de infertilidade, sendo a sequência 132 de piRNAs, os genes DDX11, Jagged 2 e ADAM18 na família 1 e os genes candidatos ADAM18 e POTE nos pacientes da família 2. / Reciprocal translocations are the most common balanced rearrangement in humans. Often individuals with balanced rearrangements show no clinical findings. However, in meiosis, the pairing between translocated chromosomes forms a quadrivalent cross-shaped figure which has the effect of making chromosome disjunction uncertain and, depending on the rearrangement, and on the segregation of the unbalanced chromosomes, the individual can be infertile, can present with an increased risk of spontaneous abortions or can have an offspring with abnormal phenotype. We have studied two families of infertile patients, who were carriers of chromosomal translocations. The objective was to characterize the cytogenetic and cytogenomic alterations related to male infertility in patients with apparently balanced rearrangements using classical cytogenetic techniques (GTG banding), molecular cytogenetics (FISH) and cytogenomics (array-CGH). Seven subjects of the family 1 were studied, including three carriers of translocation (X;22), one azoospermic. Two cases of mosaicism for Turner syndrome were detected in this family. The second family consisted of two oligozoospermic brothers with translocation (8;13). FISH was used to characterize the karyotypes as 46, XX or 46,XY, t(X;22)(p22.3;q11.2) for the members of the family 1 and 46,XY,t(8;13)(q13;q14) for family 2. Array-CGH was also performed using the Agilent platform 2x400K, to detect associated copy number variations of some of the candidate genes that could be related to infertility. In the family 1 the candidate genes were 132 piRNAs sequences and DDX11,Jagged 2 and ADAM18 genes. The candidate genes for the family 2 were ADAM18 and POT.

PGC-1 é uma família de coativadores de fatores de transcrição que controlam a expressão de diversos genes envolvidos na homeostase energética celular. As isoformas PGC-1 e estão presente em tecidos com alto metabolismo oxidativo e são capazes de aumentar biogênese mitocondrial, -oxidação de ácidos graxos e gliconeogênese em resposta à exposição ao frio, jejum e exercício. Inicialmente mostramos que macrófagos in vitro aumentaram a expressão de PGC-1 após 1h da exposição à zymosan. Com isso, hipotetizamos que PGC-1 poderia ter sua expressão aumentada em resposta a um insulto bacteriano. Para verificar nossa hipótese analisamos a expressão de PGC-1 em um modelo de pancreatite aguda (PA), caracterizada por uma forte resposta inflamatória estéril inicial, seguida, após poucos dias, por translocação bacteriana intestinal e infecção disseminada. PA foi induzida por infusão retrograda de taurocolato de sódio (2,5%). Também analisamos PGC-1 em um modelo de sepse por ligadura e perfuração cecal (CLP), cujo conteúdo intestinal é depositado no peritôneo, causando infecção grave local e disseminada. Animais tratados com Imipenem durante 48h após PA também foram analisados, bem como a interferência de PGC-1 ASO no processo de fagocitose. A expressão de PGC-1 e foi medida por PCR quantitativo. PA foi confirmada pelo aumento da amilase sérica e a inflamação sistêmica ratificada por leucocitose. PGC1 aumentou no baço e nos leucócitos circulantes 48h após PA e no lavado peritoneal 24h após PA e CLP. No entanto, PGC1 diminuiu no baço 24h após PA. Tratamento com Imipenem diminuiu PGC- 1. A diminuição de PGC-1 após transfecção com ASO levou à redução do processo de fagocitose. Assim, concluímos que ocorre aumento de PGC-1 na presença de bactérias e esse aumento está relacionado com fagocitose / PGC1 is a family of transcriptional coactivators that controls the expression of several genes involved in cell energy homeostasis. PGC1 isoforms and are present in tissues with high oxidative metabolism and are able to enhance mitochondrial biogenesis, -oxidation of fatty acids and gluconeogenesis in response to exposure to cold, fasting and exercise. Initial results showed macrophages in vitro present increased PGC-1 expression after 1h exposure to zymosan. Thus, we hypothesized that PGC-1 could be up-regulated in response to bacterial insult. We tested our hypothesis following PGC-1 expression in an acute pancreatitis (AP) model, characterized initially by a strong sterile inflammatory response, followed, few days later, by bacterial intestinal translocation and disseminated infection. AP was induced by retrograde infusion of sodium taurocholate (2.5%). We also analysed PGC-1 in a model of sepsis by cecal ligation and puncture (CLP), whose intestinal content is deposited in the peritoneum, causing a severe local and disseminated infection. Animals submitted to PA and treated with Imipenem for 48 hours were also analyzed, as well as the interference of PGC-1 ASO in phagocytosis process. PGC-1 and expression were measured by quantitative PCR. AP was confirmed by increased blood amylase and the systemic inflammation was noted by leukocytosis after 48h. PGC1 was increased in spleen and circulating leukocytes 48h after AP and in peritoneal lavage 24h after AP and CLP. On the other hand, PGC1 was decreased in spleen 24h after AP induction. Imipenem treatment decreased PGC-1. The decreased of PGC-1 after ASO transfection led to a reduction of phagocytosis process. Thus, we conclude there is a PGC-1 increase in bacterial presence and this increase is related to phagocytosis