Effects of vitamin K deficiency and its mechanisms in vertebrate's early development: zebrafish as a model

Disertação de mestrado, Ciências Biomédicas, Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, 2015

Development and standardization of a protocol for sperm cryopreservation of two important commercial oyster species

Dissertação de mestrado, Aquacultura e Pescas, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015

The effect of stress on egg quality in farmed Atlantic Cod (Gadus morhua L.)

Dissertação de mestrado, Aquacultura, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2011

Contribuição da ecografia cerebral transfontanelar para a avaliação do crescimento cerebral do recém-nascido pré-termo

Tese de doutoramento, Medicina (Pediatria), Universidade de Lisboa, Faculdade de Medicina, 2013

How hydrogen peroxide and CXCL8 modulate neutrophil recruitment "in vivo"

Tese de doutoramento, Ciências Biomédicas (Biologia Celular e Molecular), Universidade de Lisboa, Faculdade de Medicina, 2014

Serum estradiol: oocyte ratio as a predictor of reproductive outcome: an analysis of data from >9000 IVF cycles in the Republic of Ireland

Purpose The purpose of this study was to evaluate the serum estradiol (E2) per oocyte ratio (EOR) as a function of selected embryology events and reproductive outcomes with IVF. Methods This retrospective analysis included all IVF cycles where oocyte collection and fresh transfer occurred between January 2001 and November 2012 at a single institution. Patients were divided by three age groups (<35, 35–39, and ≥40 years) and further stratified into nine groups based on EOR (measured in pmol/L/oocyte). Terminal serum E2 (pmol/mL) was recorded on day of hCG trigger administration, and fertilization rate, cleavage rate, number of good quality embryos, and reproductive outcomes were recorded for each IVF cycle. Results During the study interval, 9109 oocyte retrievals were performed for 5499 IVF patients (mean = 1.7 cycles/patient). A total of 63.4 % of transfers were performed on day 3 (n = 4926), while 36.6 % were carried out on day 5 (n = 2843). Clinical pregnancy rates were highest in patients with EOR of 250–750 and declined as this ratio increased, independent of patient age. While the odds ratio (OR) for clinical pregnancy where EOR = 250–750 vs. EOR > 1500 was 3.4 (p < 0.001; 95 % CI 2.67–4.34), no statistically significant correlation was seen in fertilization, cleavage rates or number of good quality embryos as a function of EOR. Conclusions Predicting reproductive outcomes with IVF has great utility both for patients and providers. The former have the opportunity to build realistic expectations, and the latter are better able to counsel according to measured clinical parameters. A better understanding of follicular dynamics and ovarian response to gonadotropin stimulation could optimize IVF treatments going forward.

Lights and Shadows about the Effectiveness of IVF in HIV Infected Women: A Systematic Review

Background. HIV infected women have higher rates of infertility. Objective. The purpose of this literature review is to evaluate the effectiveness of fresh IVF/ICSI cycles in HIV infected women. Materials and Methods. A search of the PubMed database was performed to identify studies assessing fresh nondonor oocyte IVF/ICSI cycle outcomes of serodiscordant couples with an HIV infected female partner. Results and Discussion. Ten studies met the inclusion criteria. Whenever a comparison with a control group was available, with the exception of one case, ovarian stimulation cancelation rate was higher and pregnancy rate (PR) was lower in HIV infected women. However, statistically significant differences in both rates were only seen in one and two studies, respectively. A number of noncontrolled sources of bias for IVF outcome were identified. This fact, added to the small size of samples studied and heterogeneity in study design and methodology, still hampers the performance of a meta-analysis on the issue. Conclusion. Prospective matched case-control studies are necessary for the understanding of the specific effects of HIV infection on ovarian response and ART outcome.

O Ne bis in idem no Espaço de Liberdade, Segurança e Justiça e no Direito Europeu da Concorrência

Ne bis in idem, understood as a procedural guarantee in the EU assumes different features in the AFSJ and in european competition law. Despite having a common origin (being, in both sectors the result of the case law of the same jurisdictional organ) its components are quite distintic in each area of the integration. In the AFSJ, the content of bis and idem are broader and addressed at a larger protection of individuals. Its axiological ground is based on the freedom of movements and human dignity, whereas in european competition law its closely linked to defence rights of legal persons and the concept of criminal punishment of anticompetitive sanctions as interpreted by the ECHR´s jurisprudence. In european competition law, ne bis in idem is limited by the systemic framework of competition law and the need to ensure parallel application of both european and national laws. Nonetheless, the absence of a compulsory mechanism to allocate jurisdiction in the EU (both in the AFSJ and in the field of anti-trust law) demands a common axiological framework. In this context, ne bis in idem must be understood as a defence right based on equity and proportionality. As far as its international dimension is concerned, ne bis in idem also lacks an erga omnes effect and it is not considered to be a rule of ius cogens. Consequently, the model which the ECJ has built regarding the application of the ne bis in idem in transnational and supranational contexts should be replicated by other courts through cross fertilization, in order to internationalize that procedural guarantee and broaden its scope of application.

The Mechanism of Centriole Inactivation in Starfish Oocytes

The centrosome is the major organizing center in a cell, composed by two centrioles, one mother and one daughter, and surrounded by a pericentriolar material, which nucleates microtubules. Centriole duplication and segregation is tightly coupled to cell cycle, which guarantees that centriole number is maintained over generations. During the somatic cell cycle, a pair of centrioles duplicates, after which each daughter cell receives a pair, forming a closed cycle. However, during fertilization, if both cells were to contribute with their pair of centrioles, gamete fusion would result in the double of the normal centriole number.(...)

Multiple paternity and its consequences in the white campion " Silene latifolia "

Summary Several studies have demonstrated that the number of pollen donors siring seeds of individual fruits is frequently greater than one and, consequently, that plants have multiple mates. Multiple paternity can have important consequences at the population level. It influences the genetic variability of a population, the reproductive success of males and the fitness of females and future generations. It also influences male-male interactions for fertilization and it is fundamental in providing opportunity of female choice. I investigated the occurrence and the importance of multiple paternity within fruits in natural populations of the dioecious Silene latifolia using microsatellite DNA markers, especially developed for this study. I found that multiple paternity occurs in all populations investigated in the European range of the species, varying from one to nine sires per fruit with a mean of three, suggesting that multiple paternity is highly prevalent in natural populations. In the presence of multiple paternity I investigated if there was a female genotype influence on siring success of the males. I used the same pollen mixture from two males and applied it to three replicate females of different relatedness (two full sisters and one unrelated). I found female genotype influence in one of the two populations investigated, which might reflect different population history. Since these results suggested some degree of female choice, we investigated whether the occurrence of multiple paternity and post-pollination selection could provide opportunity for inbreeding avoidance. First, I measured inbreeding depression at different life-cycle stages for offspring obtained by single-donor crosses with brothers or unrelated males replicated on distinct flowers on the same female plant. To address inbreeding avoidance, I determined paternity in crosses using mixed pollen loads of the two males. I found significant inbreeding depression in the studied population, even under benign experimental conditions, and although the unrelated male did not sire significantly more offspring, there was an effect of genetic dissimilarity on paternity. This suggests that paternity is affected by relatedness among mates, but maybe additionally affected by other factors such as pollen competitive ability or male-female interactions. Using inbred and outbred crosses, I further investigated sex ratio bias inheritance in this species, and found that sex ratio bias of the parental generation was significantly correlated to pollen germination success of the F2 generation, which suggests that sex ratio bias in this species results from the specific X/Y combination and not only on Y performance. An effect of X and Y is consistent with sex chromosome meiotic drive. In conclusion, I found multiple paternity to be widespread in the study species and that females of similar genotype produce similar paternity shares. I found that inbreeding depression is substantial, therefore receiving pollen from several donors might lead to fewer inbred offspring, I also found an effect of genetic dissimilarity on paternity shares, which indicates that there is some ability to discriminate against related pollen, although this seems not to be the only determinant of paternity outcome. Finally I found sex ratio bias to be dependent on both X and Y chromosomes as predicted by sex chromosome meiotic drive. Résumé Plusieurs études ont démontré qu'il n'était pas rare que les graines contenues dans un même fruit soient issues de la fécondation par plusieurs pollens provenant de mâles différents, ce qui sous-entend que les plantes peuvent avoir plusieurs partenaires sexuels. La paternité multiple peut avoir d'importantes conséquences au niveau populationnel dans la mesure où elle peut influencer le degré de variabilité génétique de la population, le succès reproducteur des mâles, la fitness des femelles et des futures générations. La paternité multiple peut également avoir un impact sur les interactions mâle-mâle lors de la fertilisation et peut être considérée comme fondamentale vis-à-vis de la femelle, qui y trouve alors une opportunité de choisir son ou ses partenaires. Dans le cadre de ce travail de thèse j'ai cherché à déterminer si la paternité multiple était un phénomène observable et important dans les populations naturelles de l'espèce dioïque, Silene latifolia. Pour ce faire, j'ai utilisé des marqueurs microsatellites, spécialement développés pour cette étude. J'ai observé des phénomènes de paternité multiple dans toutes les populations de l'étude, réparties dans l'aire de distribution européenne de l'espèce. Le nombre de pères par fruit varie de un à neuf, avec un nombre moyen de trois, ce qui signifie que la paternité multiple est très répandue dans les populations naturelles. En raison de ces résultats, je me suis demandée si le génotype de la femelle influence le succès de paternité des mâles. J'ai alors réalisé des pollinisations manuelles sur la base d'un mélange de pollens issus de deux mâles, que j'ai appliqué sur trois femelles (réplicats) présentant différents degrés d'apparentement (deux soeurs. et une femelle étrangère). Il ressort de cette expérience que le génotype de la femelle peut influencer la paternité dans l'une des deux populations étudiées, ce qui pourrait refléter des différences en terme d'histoire des populations. Dans la mesure où ces résultats suggèrent un certain degré de choix chez la femelle, j'ai cherché à savoir si la paternité multiple et la sélection post-pollinisation pouvaient être des moyens d'éviter les croisements consanguins. Dans un premier temps, j'ai évalué la dépression de consanguinité à différentes étapes du cycle de vie chez des descendants issus de croisements à un seul donneur, celui-ci étant alternativement un frère ou un étranger, répliqués sur plusieurs fleurs d'une même plante femelle. Afin d'estimer l'évitement de croisements consanguins, j'ai effectué des croisements dont le pollen était un mélange des deux mâles (frère et étranger), puis j'ai déterminé la paternité dans les fruits obtenus. J'ai pu mettre en évidence un effet de dépression de consanguinité- significatif dans les populations étudiées, même dans des conditions expérimentales moins rudes qu'à l'extérieur. Bien que le mâle étranger n'ait pas engendré un nombre significativement plus important de graines, il y avait un effet de dissimilarité génétique sur la paternité. Ceci suggère que la paternité est affectée par le degré d'apparentement entre les partenaires, mais qu'elle peut aussi être affectée par d'autres facteurs tels que la compétitivité du pollen ou encore par les interactions mâles-femelles. L'utilisation de croisements consanguins et hybrides m'a également permis d'étudier l'héritabilité du biais de sex ratio chez cette espèce. Il s'est avéré que le biais de sex ratio de la génération parentale était significativement corrélé au succès de germination du pollen de la génération F2, ce qui signifie que, chez cette espèce, le biais de sex ratio résulte d'une combinaison spécifique de X/Y et non uniquement de la performance de Y. Un effet de X et Y est compatible avec l'hypothèse de distorsion de ségrégation méiotique des chromosomes sexuels. En conclusion, il ressort de mes résultats que la paternité multiple est un phénomène largement répandu chez S. latifolia et la paternité accomplie par un mâle est plus similaire entre soeurs qu'avec une femelle étrangère J'ai également mis en évidence que la dépression de consanguinité a un impact considérable; aussi, recevoir du pollen de plusieurs donneurs différents pourrait permettre à la femelle de produire moins de descendants consanguins. J'ai aussi trouvé un effet de la dissimilarité génétique sur le partage de paternité, ce qui indique que la discrimination contre le pollen d'apparentés est possible, bien que cela ne semble pas être le seul facteur déterminant dans le résultat de la paternité. Enfin, j'ai trouvé que le biais de sex ratio est dépendant des deux chromosomes X et Y, conformément à la théorie de distorsion de ségrégation méiotique des chromosomes sexuels.

Adiponectin isoform distribution in serum and in follicular fluid of women undergoing treatment by ICSI.

Adiponectin is an adipokine, present in the circulation in comparatively high concentrations and different molecular weight isoforms. For the first time, the distribution of these isoforms in serum and follicular fluid (FF) and their usefulness as biological markers for infertility investigations was studied. In vitro study. University based hospital. Fifty-four women undergoing intracytoplasmic sperm injection (ICSI). Oocytes were retrieved, fertilized in vitro using ICSI, and the resulting embryos transferred. Serum was collected immediately prior to oocyte retrieval. Adiponectin isoforms (high molecular weight (HMW), medium and low molecular weight) were determined in serum and FF. Total adiponectin and the different isoform levels were compared with leptin and ovarian steroid concentrations. Adiponectin isoforms in serum and FF. Adiponectin isoform distribution differed between serum and FF; the HMW fraction made up half of all adiponectin in the serum but only 23.3% in the FF. Total and HMW adiponectin in both serum and FF correlated negatively with the body mass index and the concentration of leptin. No correlations were observed for total adiponectin or its isoforms with estradiol, progesterone, anti-Mullerian hormone, inhibin B, or the total follicle stimulating hormone (FSH) dose administered during the ovarian stimulation phase. This study shows for the first time that adiponectin isoform distribution varies between the serum and FF compartments in gonadotropin stimulated patients. A trend towards higher HMW adiponectin serum levels in successful ICSI cycles compared to implantation failures was observed; studies with larger patient groups are required to confirm this observation.

pH como un trazador de la variabilidad biogeoquímica en el Sistema de Humboldt

Se analizó información sobre parámetros biogeoquímicos como pH, CO2 parcialmente disuelto, clorofila-a, oxígeno, salinidad y temperatura, obtenidos en el Sistema de Humboldt frente a Perú en los años 2007-2009, a fin de comprender la importancia del pH como una variable clave para trazar la variabilidad biogeoquímica del Sistema de Afloramiento de Humboldt. Las Aguas Costeras Frías (ACF) ricas en nutrientes evidencian una relación inversa con el pH, en ese sentido valores de 7,6 a 8,0 se encontraron asociados a la ocurrencia de eventos de afloramiento; en condiciones frías como La Niña 2007 el pH predominante se encuentra por debajo de 8,0, y en el caso de las Aguas Subtropicales Superficiales presentan un pH entorno a 8,3. La productividad en los veranos se incrementa debido a factores como la intensidad de luz generándose núcleos de clorofila-a superiores a 10,0 μg.L-1; como constituyentes de la reacción bioquímica de fotosíntesis se tiene en cuenta la forma inmediata del compuesto CO2 y el consumo de iones hidronio; en situaciones extremas de fertilización, se tiene elevado pH entre 8,2 e inclusive 9,0, en donde los contenidos de oxígeno disuelto superan los 6,0 mL.L-1.

Male body size and breeding tubercles are both linked to intra-sexual dominance and reproductive success in the minnow

Male dominance hierarchies are usually linked to relative body size and to weapon size, that is, to determinants of fighting ability. Secondary sexual characters that are not directly used as weapons could still be linked to dominance if they reveal determination or overall health and vigour and hence, indirectly, fighting ability. We studied the mating behaviour of the minnow, Phoxinus phoxinus, a cyprinid fish in which males develop breeding tubercles during the spawning season. The function of these breeding tubercles is still not clear. Using microsatellite markers, we determined male reproductive success under controlled conditions. The minnows were territorial and quickly established a dominance hierarchy at the beginning of the spawning season. Dominance was strongly and positively linked to fertilization success. Although body size and number of breeding tubercles were not significantly correlated in our sample, both large males and males with many breeding tubercles were more dominant and achieved higher fertilization success than small males or males with few tubercles. We found multimale fertilization in most clutches, suggesting that sperm competition is important in this species. Females showed behaviour that may be linked to spawning decision, that is, male dominance might not be the only determinant of male reproductive success in minnows

Evolution of the mating system in colonizing plants.

Colonization is likely to be more successful for species with an ability to self-fertilize and thus to establish new populations as single individuals. As a result, self-compatibility should be common among colonizing species. This idea, labelled 'Baker's law', has been influential in discussions of sexual-system and mating-system evolution. However, its generality has been questioned, because models of the evolution of dispersal and the mating system predict an association between high dispersal rates and outcrossing rather than selfing, and because of many apparent counter examples to the law. The contrasting predictions made by models invoking Baker's law versus those for the evolution of the mating system and dispersal urges a reassessment of how we should view both these traits. Here, I review the literature on the evolution of mating and dispersal in colonizing species, with a focus on conceptual issues. I argue for the importance of distinguishing between the selfing or outcrossing rate and a simple ability to self-fertilize, as well as for the need for a more nuanced consideration of dispersal. Colonizing species will be characterized by different phases in their life pattern: dispersal to new habitat, implying an ecological sieve on dispersal traits; establishment and a phase of growth following colonization, implying a sieve on reproductive traits; and a phase of demographic stasis at high density, during which new trait associations can evolve through local adaptation. This dynamic means that the sorting of mating-system and dispersal traits should change over time, making simple predictions difficult.