Le syndrome des ovaires polykystiques (SOPK) touche entre 5 à 10 % des femmes en âge de procréer et est associé à de nombreuses complications. Ce désordre endocrinien est caractérisé par des niveaux circulants élevés d’androgènes, dont la production est principalement modulée par la P450c17 et son cofacteur, soit la P450oxydoréductase (POR). Plusieurs études démontrent que l’hyperandrogénie présente chez les femmes SOPK pourrait être causée par la formation de phénomènes toxiques survenant à la suite de l’exposition des tissus non adipeux à un excès d’acides gras non estérifiés (AGNE), appelé lipotoxicité. Ainsi, l’objectif de cette étude est de déterminer les mécanismes cellulaires sous-jacents à l’hyperandrogénie induite par la surexposition des cellules productrices d’androgènes aux AGNE. Pour y arriver, les cellules surrénaliennes bovines (CSB) ont été exposées en présence de forskoline (Fsk; 1X/2 jours; 10 µM; activateur des adénylates cyclases) et d’oléate (acide gras monoinsaturé, 2X/jour; 200 µM) durant 48 heures. Par la suite, le milieu de culture a été prélevé afin de doser le DHEA (principal androgène surrénalien) par ELISA. De plus, les protéines ont été récoltées afin de déterminer l’expression protéique de la P450c17 et de POR par Western blot. Finalement, pour déterminer les activités 17αhydroxylase et 17,20-lyase de la P450c17, la concentration de plusieurs stéroïdes a été déterminé par LC-MS/MS et le ratio produit/substrat a été effectué. Les résultats sont présentés en moyenne ± SEM. Ainsi, sous stimulation à la Fsk, la présence de 200 µM d’oléate (vs absence d’oléate) augmente la production de DHEA de 114% par les CSB (n=17; 214 ± 20% vs 100 ± 0%; p<0,0001). De plus, l’ajout d’oléate n’affecte pas l’expression de la P450c17 (n=8; 98 ± 6% vs 100 ± 0%; p=0,74) et de POR (n=7; 119 ± 13% vs 100 ± 0%; p= 0,22). Finalement, la présence d’oléate augmente l’activité 17αhydroxylase de la P450c17 de 124% (n=7; 224 ± 19% vs 100 ± 0%; p= 0,02) et tends à augmenter l’activité 17,20-lyase de la P450c17 de 81% (n=7; 181 ± 28% vs 100 ± 0%; p= 0,08). Ainsi, l’augmentation de la production des androgènes induite par les AGNE pourrait être due principalement à leurs effets sur l’augmentation des deux activités enzymatiques de la P450c17, sans effet significatifs sur l’expression de la P450c17 ni de son cofacteur POR. Les mécanismes sous-jacents à l’augmentation des activités de la P450c17 demeurent à élucider.

Made available in DSpace on 2014-08-20T14:38:48Z (GMT). No. of bitstreams: 1 dissertacao_diego_andres_velasco_acosta.pdf: 554045 bytes, checksum: 4c51ec170f50997dc62e7caef5c6f9d2 (MD5) Previous issue date: 2012-02-28 / Negative energy balance (NEB) has been associated with changes in hormones that support follicular development in early lactation. Prepartum recombinant bovine somatotropin (rbST) injection led to reduced non-esterified fatty acids (NEFA) and β-hydroxybutyrate (BHBA) in the early postpartum period. Therefore, prepartum administration of somatotropin may result in metabolic changes that benefit the energetic balance of the postpartum dairy cows. The aim of this study was to determine the effect of prepartum injections of somatotropin in dairy heifers with high BCS on the markers of NEB, resumption of ovarian activity and milk production. Holstein heifers (n=20) with high body condition score (scale 1-5; BCS>3.5) were randomly divided into two groups: somatotropin group (n=10) that received two doses of 500 mg of rbST at -28 and -14 days from calving; and control group (n=10) that received applications of placebo in a similar manner to somatotropin group. Blood samples were collected weekly from 28 to 42 d after calving to evaluate BHBA and NEFA concentrations. Follicular development was also monitored via ultrasound examinations starting at days 10 postpartum and every 3 days until ovulation. Prepartum somatotropin administration did not affect (P =0.28) the moment of the first postpartum ovulation. The proportion of cows ovulating the first follicular wave postpartum was not different between groups (P=0.49). There was no effect (P>0.05) of prepartum treatment on the diameter of the first postpartum dominant follicle. There was a interaction days by group for plasma NEFA concentrations during the prepartum period (P= 0.03) and a tendency for the day (P=0.07) but no effect on the group (P=0.35). There was only an effect of the week (P<0.001) for postpartum NEFA concentrations. Postpartum NEFA concentration was higher at days 0, 7 and 14 than at 21, 28, 35 and 42 (P<0.05). For pre and postpartum BHBA there was not effect of days (P>0.05), group (P>0.05) or days by group (P=0.05). In conclusion, prepartum somatotropin treatment in dairy heifers with high body condition did not improve parameters that indicate that these heifers had a less severe NEB during the early postpartum period,had not affect development of the first follicular wave in the postpartum period and milk production. / O balanço energético negativo (BEN) tem sido associado com alterações nos hormônios que auxiliam o desenvolvimento folicular no início da lactação. A aplicação pré-parto de somatotropina recombinante bovina (rbST) pode levar a uma redução sérica dos ácidos graxos não esterificados (AGNE) e β-hidroxibutirato (BHBA) no período pós-parto. Portanto, a administração pré-parto de somatotropina pode resultar em alterações metabólicas que beneficiam o equilíbrio energético da vaca leiteira após o parto. O objetivo deste estudo foi determinar o efeito da administração pré-parto de somatotropina em novilhas leiteiras com elevado escore de condição corporal (ECC) sobre marcadores BEN, a retomada da atividade ovariana e produção de leite. Foram utilizadas novilhas da raça Holandês (n = 20) com ECC elevada (Escala 1-5; ECC > 3,5), foram divididos aleatoriamente em dois grupos: grupo somatotropina (n = 10) que recebeu duas aplicações de 500 mg de rbST nos dias -28 e -14 referente ao parto e grupo controle (n = 10) que recebeu aplicações de placebo no mesmo local e forma do grupo somatotropina. Amostras de sangue foram coletadas entre os dias -28 a 42 relativos ao parto para a avaliação das concentrações de BHBA e AGNE. O desenvolvimento folicular também foi monitorado através de exames de ultrassom a partir do dia 10 pós-parto, e cada 3 dias até o momento da primeira ovulação. A administração pré-parto de somatotropina não afetou (P = 0,28) o momento da primeira ovulação pós-parto. A proporção de vacas que ovularam na primeira onda folicular pós-parto não foi diferente entre os grupos (P = 0,49). Não houve efeito (P> 0,05) do tratamento pré-parto de somatotropina sobre o diâmetro do folículo dominante da primeira onda folicular pós-parto. Houve interação entre o dia e grupo para as concentrações plasmáticas de AGNE durante o período pré-parto (P = 0,03) e uma tendência para o dia (P = 0,07), mas nenhum efeito sobre o grupo (P = 0,35). Houve apenas um efeito da semana (P <0,001) para as concentrações de AGNE no pós-parto. As concentrações de AGNE pós-parto foram maiores nos dias 0, 7 e 14 do que em 21, 28, 35 e 42 (P <0,05). Para BHBA pré e pós-parto não houve efeito de dias (P> 0,05), grupo (P > 0,05) ou dias por grupo (P>0,05). Em conclusão, o tratamento pré-parto de somatotropina em novilhas leiteiras com condição corporal elevada não melhorou os parâmetros que indicam que estas novilhas tiveram um BEN menos grave durante o período pós-parto, não teve efeito sobre o desenvolvimento da primeira onda folicular pós-parto e produção leiteira.

Argonautes are conserved RNA-binding proteins that can regulate gene expression post transcriptionally through a process known as RNA interference (RNAi). This is done through the use of small RNAs, e.g. sRNAs that act as a guide for the argonautes, allowing for sequence-specific binding to the target site. This interaction has been studied in many organisms, one of which is the model organism Dictyostelium discoideum. D. discoideum is an amoeba that has been used extensively in genetic experiments due to its unique lifestyle, and ease of use. Being a eukaryotic, unicellular organism, it proves to be a great tool for the study of regulatory systems in eukaryotes, allowing us to study this argonaute-sRNA interaction in detail. By analysing which RNAs bind to the argonautes, we can better understand which genes these proteins regulate and what role RNAi has in the organisms as a whole.  In this study, I investigate three of the five argonautes found in D. discoideum, namely agnA, agnC and agnE. By transforming FLAG-tagged versions of these genes into the amoeba, I successfully express two of these modified proteins in D. discoideum and verified expression by using antibodies designed specifically to recognise the FLAG-tags. This opens up the possibility for the characterisation of the argonaute proteins to better understand their role and function in the regulation of genes. / <p>The Biology Education Centre (IBG) is the responsible department. </p><p></p><p>Presentation has been made through Zoom. </p>

Genom en innehållslig idéanalys av Gustaf Auléns bok ‘Den kristna försoningstanken’ och Agne Nordlanders bok ‘Korsets mysterium’ med C. Baxter Krugers teologiska ståndpunkt i hans bok ‘Jesus and the Undoing of Adam’ som den vetenskapliga utgångspunkten för min analys ger jag mig i kast med ett tidlöst ämne som ställer mig i en mångtusenårig tradition. Jag hoppas kunna göra en teologisk analys och bedömning av vad litteraturvalet har att säga om begreppet Guds vrede och därigenom ge exempel på hur försoningslära kan förankras i patristisk teologi. / Through a thematic analysis of Gustaf Aulén's book 'Den kristna försoningstanken' and Agne Nordlander's book 'Korsets mysterium', using C. Baxter Kruger's theological standpoint in his book 'Jesus and the Undoing of Adam' as the scholarly foundation for my analysis, I delve into a timeless subject that places me within a tradition spanning millennia. I aim to conduct a theological analysis and assessment of what the choice of literature has to say about the concept of ‘the wrath of God’, thereby providing examples of how atonement theology can be anchored in patristic theology.