Yes / The coexistence of hermaphrodites and female-sterile individuals, or androdioecy, has been documented in only a handful of plants and animals. This study reports its existence in the plant species Cardamine amara (Brassicaceae), in which female-sterile individuals have shorter pistils than seed-producing hermaphrodites. Morphological analysis, in situ manual pollination, microsatellite genotyping and differential gene expression analysis using Arabidopsis microarrays were used to delimit variation between female-sterile individuals and hermaphrodites. Female sterility in C. amara appears to be caused by disrupted ovule development. It was associated with a 2.4- to 2.9-fold increase in clonal propagation. This made the pollen number of female-sterile genets more than double that of hermaphrodite genets, which fulfils a condition of co-existence predicted by simple androdioecy theories. When female-sterile individuals were observed in wild androdioecious populations, their ramet frequencies ranged from 5 to 54 %; however, their genet frequencies ranged from 11 to 29 %, which is consistent with the theoretically predicted upper limit of 50 %. The results suggest that a combination of sexual reproduction and increased asexual proliferation by female-sterile individuals probably explains the invasion and maintenance of female sterility in otherwise hermaphroditic populations. To our knowledge, this is the first report of the coexistence of female sterility and hermaphrodites in the Brassicaceae.

According to the World Health Organization (WHO), 15% of couples in reproductive age suffer from infertility problems, and up to 60% of cases are caused by male factor. Causes of this condition could be genetic background, environmental factors and various diseases, including diabetes mellitus (DM). The aim of this study was to investigate the effects of DM on reproductive parameters and expression of selected testicular genes using mouse model (FVB inbred mouse strain). DM (type 1) was artificially induced by chemical substance streptozotocin, which causes destruction of pancreatic β cells. These mice were exposed to diabetic condition for 6 weeks and then subjected to analysis. Our results have shown that diabetic condition had an impact on body weight, weight of reproductive organs as well as kidneys and livers. We also observed decreased concentration and viability of diabetic sperm compared to control. Moreover, we noticed increased staining with apoptotic marker annexin V. Further, we evaluated changes of sperm nuclear proteins - protamines. In diabetic animals, we observed higher number of sperm with insufficient protamination. Nevertheless, protamine 1 to protamine 2 ratio (P1/P2), a marker of male fertility, was not altered in sperm of diabetic animals compared to control. Regarding the...

Depuis quelques décennies une diminution de la qualité du sperme a été constatée dans la majorité des pays occidentaux. Si les raisons de cette diminution sont encore incomplètement comprises, des facteurs environnementaux pourraient y contribuer grandement. Parmi eux, l’exposition à certains matériaux, comme les nanomatériaux et l’aluminium, a grandement augmenté durant cette même période. Notre objectif a donc été d’évaluer l’impact de ces expositions sur la fonction de reproduction masculine. Pour ce faire, nous avons réalisé deux études de la biodistribution testiculaire des particules après injection par voie intramusculaire sur un modèle de souris, une étude clinique visant à évaluer la charge du plasma séminal en nanoparticules et à la corréler avec le nombre de spermatozoïdes dans l’éjaculat et une étude clinique visant à évaluer l’impact de la charge spermatique en aluminium sur les paramètres spermatiques. Les résultats de ces travaux couplés à l’analyse de la littérature nous rassurent sur la reprotoxicité masculine des nanoparticules mais montrent l’existence d’un impact potentiellement négatif de l’aluminium. Dans les deux cas, de nouvelles études devront poursuivre l’exploration de ces questions / In recent decades a decrease in sperm quality was observed in most Western countries. While the reasons for this decline are not yet fully understood, environmental factors could greatly contribute. Among them, exposure to materials such as nanomaterials and aluminium, has greatly increased during this period. Therefore, our goal was to assess these exposures impact on male reproductive function. To do so, we conducted two studies to determine testis biodistribution of particles after intramuscular injection in a mouse model. We also conducted two clinical studies, first one to assess the burden of nanoparticles in seminal plasma and to correlate it with sperm count and the second one to evaluate the impact of the aluminum load in semen on sperm parameters. The results of these works and the analysis of literature reassure us about male reproductive toxicity of nanoparticles but revealed a potentially negative impact of aluminum. In both cases, new studies will be needed to further explore these issues

La plupart des études sur l’influence de la température sur la production des spermatozoïdes portent en grande partie sur les vertébrés. Néanmoins, les invertébrés constituent la majorité de la biodiversité terrestre animale, sont également plus sensibles à ces variations de température. Les travaux réalisés au cours de cette thèse ont porté sur la compréhension des capacités de reproduction, et sur l’influence d’une augmentation de température sur les fonctions mâles chez Nasonia vitripennis, un hyménoptère parasitoïde. Ce travail de thèse m’a permis de confirmer que chez cette espèce, la spermatogenèse était synchronisée et de décrire pour la première fois, un système de stockage intermédiaire des spermatozoïdes entre les testicules et les vésicules séminales. De plus, j’ai pu mettre en évidence que la spermatogénèse était sensible à une augmentation de température pendant le développement, altérant le sexe ratio de la descendance par des modifications d’allocations des sexes par les femelles. Ces résultats apportent de nouvelles connaissances sur la fertilité mâle chez cette espèce et démontrent la sensibilité de la spermatogenèse à la température. / Many studies on the impact of the temperature on spermatogenesis have largely focused on vertebrates. Nevertheless, invertebrates constitute the vast majority of terrestrial biodiversity, and are especially vulnerable to variations of temperatures. The studies realized during my thesis are focused on understanding male reproductive capacities and effects of heat stress on male fertility in a parasitic wasp Nasonia vitripennis. This work allowed to confirm that spermatogenesis was synchronized, and to describe for the first time a system of spermatozoa regulation between testis and seminal vesicles. Moreover, I was able to demonstrate that spermatogenesis was sensible to temperature variation during male development, and the offspring sex ratio was altered by modifications of sex allocation. These findings open the way to the description of male fertility in this species, and show the sensitivity of spermatogenesis to temperature variation.

No description available.

Our research aims at understanding the roles of seminolipid (sulfogalactosylglycerolipid or SGG) and its associated membrane domains in male reproduction. SGG is a sulfoglycolipid present selectively and abundantly in mammalian male germ cells. Therefore, information on its properties would be relevant towards the development of male fertility biomarkers and spermicide-based contraceptives. We have shown that SGG has direct affinity for zona pellucida (ZP, egg extracellular matrix) and plays a role in the formation of sperm lipid rafts, the ZP-binding platforms on the sperm anterior head plasma membrane (APM), the initial ZP binding site. For a better understanding of mechanisms underlying sperm-ZP interaction, I performed proteomic characterization of APM vesicles (SGG-associated membrane domains with ZP affinity) isolated from sperm before and after capacitation, a process through which sperm gain maximal ZP affinity. Proteomic results revealed that capacitated APM vesicles contained high-molecular-weight protein complexes, with higher ZP affinity and levels of ZP-binding proteins as compared with those of the non-capacitated samples. ZP-binding proteins known to exist in the acrosome (i.e., zonadhesin, proacrosin/acrosin) were found in these APM protein complexes. Immunofluorescence suggested that a fraction of these proteins trafficked from the acrosome to APM during capacitation. These findings provided a new mechanism on how sperm gain full ZP-binding ability during capacitation. Since SGG is a major component of APM, proper SGG levels at this site would be important for male fertility. Levels of sperm SGG are regulated through the synthesis and degradation. In fact, lack of SGG-synthesis enzymes causes a spermatogenesis disruption, resulting in male infertility. However, significance of SGG degradation remains unknown. SGG can be desulfated in vitro by arylsulfatase A (ARSA), an enzyme existing in the acrosomes of sperm/spermatids and lysosomes of Sertoli cells, testicular somatic cells that nurture developing germ cells. Sertoli cells also phagocytose ~50% of germ cells that become apoptotic during spermatogenesis. To understand physiological importance of SGG degradation, the fertility status and SGG levels of Arsa-/- male mice were determined. We found that Arsa-/- males became subfertile when they were older than 5 months, and when they were 8-month-old (~40-year-old men) they produced sperm at 50% wild type rate. Arsa-/- sperm had minimal in vitro fertilizing ability and a number of them showed abnormal morphology. Quantitative mass spectrometry revealed that SGG levels in Sertoli cells of 8-month-old Arsa-/- mice were increased to ~250% of the wild type level; this SGG accumulation may lead to a decrease in Sertoli cell ability to support spermatogenesis. However, SGG levels in sperm of 8-month-old Arsa-/- mice were ~50% of the wild type value, a result that partly explained the decreased fertilizing ability of these sperm. The reduced SGG level of Arsa-/- sperm was likely due to a lack of SGG’s building-block lipid (palmitylpalmitoylglycerol) putatively generated in Arsa-/- Sertoli cells and recycled to the next generation of primary spermatocytes for SGG synthesis. Hence, levels of sperm SGG are a promising bioindex for male fertility. Since Sertoli cells also regulate SGG homeostasis, their functionality should be now included in male fertility/subfertility diagnosis.

La présence de taureaux sub-fertiles sur le marché de l’Insémination Animale (IA) influence négativement l’efficacité des élevages. L’évaluation de la fertilité des taureaux, basée sur l’analyse combinée de marqueurs génétiques, morphologiques, cinétiques et métaboliques de la semence, n’est pas suffisante pour identifier les taureaux sub-fertiles avant leur entrée en production. Cela suggère l’implication d’autres facteurs, notamment d’origines épigénétiques. Parmi les marques épigénétiques, la méthylation de l’ADN tient une place essentielle : son remaniement est en effet indispensable aux processus fondamentaux que sont la différenciation des cellules germinales, la spermatogénèse et le développement embryonnaire précoce. Alors que chez l’Homme, de nombreuses études ont montré que des altérations des profils de méthylation spermatiques sont associées à la sub-fertilité, très peu de données existent chez le bovin. L’objectif de ce travail de thèse est la caractérisation du méthylome de la semence bovine et l’identification de nouveaux marqueurs fiables de la fertilité mâle à un stade précoce. Cette étude s’inscrit dans un large projet intitulé SeQuaMol (pour « Qualité Moléculaire de la Semence »), mis en place au sein d’un laboratoire commun entre l’INRA et la fédération ALLICE. La caractérisation du méthylome spermatique bovin a été réalisée en utilisant une approche multi-échelle (globale, pangénomique et séquence-spécifique). Les analyses ont permis de révéler l’hypométhylation très marquée du spermatozoïde bovin. L’hypométhylation affecte des gènes importants pour la différenciation de la lignée germinale, les fonctions spermatiques, ainsi que des séquences satellites. L’identification de biomarqueurs de la fertilité a été réalisée en utilisant une approche pangénomique (Reduced Representation Bisulfite Sequencing, RRBS). L’analyse a été effectuée sur une cohorte de 94 taureaux, dont les individus de races Holstein et Montbéliard ont été catégorisés en fonction de l’adéquation entre un indicateur génétique de la fertilité et leur fertilité réelle. Le dispositif inclus également des taureaux de 4 autres races pour obtenir une estimation de la variabilité épigénétique liée à la race. Cette analyse a nécessité l’optimisation et l’automatisation du protocole pour la préparation des banques RRBS à haut-débit, ainsi que la mise au point de l’ensemble de la procédure de traitement bio-informatique et statistique des données. Plusieurs milliers de biomarqueurs de la fertilité ont été identifiés et permettent de prédire de façon robuste le statut de fertilité. De plus, une démarche d’intégration des données de génotype et d’épigénotype a été amorcée, soulignant les interactions potentielles en ces strates d’informations. Enfin, nous avons mis en évidence l’influence de l’âge à la production de semence sur le méthylome. L’ensemble de ces données souligne que les modifications du méthylome spermatique peuvent affecter des gènes impliqués dans les processus précoces et plus tardifs du développement, ainsi que quelques voies du fonctionnement du spermatozoïde. L’ensemble des biomarqueurs identifiés serviront de base à la poursuite du projet SeQuaMol, dont l’aboutissement sera le développement d’outils technologiques et statistiques pouvant être utilisés en routine pour améliorer la prédiction de la fertilité mâle. / The presence of subfertile bulls in the market of Animal Insemination negatively influences the efficacy of breeding farms. The evaluation of bull fertility, based on the combined analysis of genetic, morphological, kinetic and metabolic markers of the semen, is not sufficient to identify subfertile bulls before entering semen production. It suggests the implication of other factors, especially epigenetic ones. Within the epigenetic markers, DNA methylation holds a crucial position: indeed, its reprogramming is indispensable to the fundamental processes that are germinal cell differentiation, spermatogenesis and the embryonic development. Whereas several studies have showed that the alteration of spermatic methylation profiles are associated with subfertility in humans, only a little data exists concerning bovines. The aim of this thesis is the characterization of the methylome of bovine semen and the identification of new reliable markers of male fertility at an early stage. This study is part of a larger project called SeQuaMol (Molecular Quality of Semen) which rely on a common laboratory between INRA and the ALLICE federation. The characterization of the bovine sperm methylome was achieved by using a multiscale approach (global, pangenomic and sequencespecific). The analyses made it possible to observe the hypomethylation of the bovine semen. Hypomethylation affects genes that are crucial for the differentiation of the germline, spermatic functions, and also on satellite sequences.The identification fertility biomarkers was carried out by using a pangenomic approach (Reduced Representation Bisulfite Sequencing, RRBS). The analysis has been performed on a cohort of 94 bulls, including subjects of the Holstein race and Montbeliard race, categorized according to the adequacy between a genetic indicator of fertility and their actual fertility. The process also includes bulls from 4 other breeds in order to obtain an estimate of the genetic variability linked to the breed. This analysis has required the optimization and the automation of the protocol for the high throughput preparation of RRBS libraries, as well as the development of the whole bioinformatic pipeline and data statistics. Several thousands of biomarkers of fertility have been identified, which allow to predict in a robust way the fertility status. Furthermore, a process of integration of genotype and epigenotype data has been started, which underlines the potential interaction between these levels of information. Finally, we have highlighted the influence of the age of semen production on the methylome. Altogether, theses data suggest that modifications of the semen methylome can affect genes that are involved in the process of early and late embryo development, and parts of the functioning of the sperm cell. The biomarkers identified will form a basis for the pursuit of the SeQuaMol project, of which the completion will be the development of technological and statistical tools that may be used routinely to improve male’s fertility prediction.

No description available.

Reports of endocrine disrupting potential of common environmental chemicals and the effects on reproductive health are well documented in literature. It has been suggested that deteriorating male reproductive health could be due to in utero exposures to these chemicals. The effects mediated through endocrine disrupting chemicals (EDCs) are on the fetus and may therefore be trans-generational. Ultimately, these chemicals land up in aquatic systems and affect wildlife and humans. Humans are exposed to these chemicals through multiple routes including atmosphere, water, occupational, domestic and food consumption. South Africa (SA) is an important livestock producer with about 13.8 million cattle within the feedlot industry contributing up to 80% of the total beef production. Veterinary growth stimulants (VGS) are used by beef producers to enhance growth in cattle. In SA, the following five VGS have been approved for use in beef products under the Register Act 36 of 1947, estradiol, progesterone and testosterone (natural), α'-zearalanol and trenbolone (synthetic). These VGS and their metabolites are environmentally stable compounds. The excretions from the animals are not treated and land up in the local aquatic systems, indirectly posing a health risk. In SA no research has been done on VGS associated with feedlot activities. The aim of this study was to investigate the effects of a mixture of VGS, as possible EDCs on the reproductive health and thyroid function in male rats in utero, during lactation and life-time exposure. The (anti)estrogenic and (anti)androgenic activity in water from specific feedlots was determined by using a battery of screening bio-assays. Water samples were collected over a period of a year and assessed for EDC activity in the recombinant yeast screen (YES), the T47D-KBluc (estrogenic) and the MDA-Kb2 (androgenic) bioassays. The OECD (Organization for Economic Co-operation and Development) 415 protocol, (1983) for a one-generation reproduction toxicity study, was modified to accommodate one control and three experimental groups. The experimental groups were orally gavaged with mixtures of: zilpaterol, diethylstilbestrol (DES) and α-zearalanol (Group 2; estogenic); with β'-trenbolone and methyltestosterone (MT) (Group 3; androgenic); a combination of compounds (Group 4; estrogenic and androgenic) and the Control group received cottonseed oil only. The bio-assay results indicated that water samples analysed from selected feedlots contained compounds with estrogenic activity. The shorter anogenital distance (AGD) (Group 3), decreased seminal vesicle mass (Group 4), decreased prostate mass (Group 4), increased lumen diameter (Group 3 and 4), lowered sperm concentration (Group 3), and increased T4 (Group 2 and 3) differed significantly from the control. The body weight of the males in Group 2 in the F2 generation was significantly lower than the control. The F2 females in Group 2, 3 and 4 were also significantly lower than the control. The reduced AGD, decreased seminal vesicle and increased T4 (thyroxine) might be the result of an estrogenic effect. The reduced sperm concentration might be the result of in utero and lactation exposure to these VGS. The bio-assays confirmed estrogenic activity in the feedlot water sources. The reproductive toxicology study findings confirm the hypothesis that VGS can act as EDCs and could therefore be responsible for negative reproductive effects and thyroid function. More research is needed to investigate the effects of VGS mixtures at different concentrations on male reproductive health, thyroid function and their offspring. AFRIKAANS : Goed gedokumenteerde literatuur dui aan dat chemikalieë wat algemeen in die omgewing gevind word, die potensiaal het om die manlike voortplantingstelsel aan te tas. Dit word gespekuleer dat in utero blootstelling verantwoordelik kan wees vir hierdie agteruitgang. Die fetus en daarop- volgende geslagte se gesondheid kan ook beÏnvloed word deur chemikalieë. Hierdie chemikalieë het die potensiaal om die watersisteme te bereik en gevolglik dier en menslike gesondheid te beÏnvloed. Blootstelling kan plaasvind deur verskeie roetes wat die atmosfeer, water, werksomstandighede, huishoudelike produkte en gekontamineerde voedsel insluit. Suid-Afrika (SA) is 'n belangrike produsent van vleisprodukte met omtrent 13.8 miljoen beeste wat bydra tot 80% van die vleisproduksie. Veterinêre-groei-stimulante (VGS) word gebruik om die vleisproduksie te verbeter. Vyf groei stimulante naamlik estradiol, progesteroon, testosteroon (natuurlike), α-zearalanol en trenboloon (sinteties) is goedgekeur onder die Wet 36 van 1947, vir groei produksie van beeste. Hierdie VGS en hul metaboliete is stabiel in die natuur. Die fekale en urinere uitskeidingsprodukte van die diere word nie behandel nie en eindig op in ons waterstelsels. Geen navorsing is nog in SA gedoen om die potensiële bydraes wat voerkrale tot die besoedeling van water lewer, te bestudeer nie. Die doel van die studie was om die gesamentlike effekte van mengsels VGS as moontlike endokrien-ontwrigtende chemicalieë (EOC) op die manlike voortplantingstelsel en tiroïdhormone van mannetjiesrotte na in utero-, gedurende laktasie- en na 'n leeftyd-blootstelling te bepaal. Die (anti)estrogeniese en (anti)androgeniese aktiwiteit in water vanaf spesifieke voerkrale is met behulp van 'n reeks biologiese seltoetse bepaal. Watermonsters is geanaliseer met die gisseltoets (YES)(estrogenies), die T47D-KBluc (estrogenies) en die MDA-Kb2 (androgenies). Die OECD 415 protokol (1983) vir een generasie reproduktiewe toksologie toets was aangepas om een kontrole en drie eksperimentele groepe te huisves. Die eksperimentele groepe rotte is oraal gedoseer met 'n mengsel van zilpaterol, dietielstilbestrol (DES) en α-zearalanol (Groep 2); β-trenboloon en metieltestosteroon (Groep 3); 'n kombinasie van al bogenoemde (Groep 4); en 'n kontrole groep wat katoensaad olie VGS ontvang het nie. Estrogeniese aktiwiteit en sitotoksisiteit was teenwoordig in die water vanaf die voerkrale. Die verkorte anogenitale afstand (AGD) (Groep 3), kleiner seminale vesikel (SV) massa (Groep 4), kleiner prostaat massa (Groep 4), groter lumen deursneë (Groep 3 en 4), laer spermtelling (Groep 3), verhoogde T4 (Groep 2 en 3), het almal statisties-betekenisvol van die kontrole groep verskil. In die F2 generasie het die liggaamsmassas van die mannetjies in Groep 2 en liggaamsmassas van die wyfies in Groepe 2, 3 , 4, almal statisties-betekenisvol laer as die kontrole Groep. Die verkorte AGD, kleiner SV en verhoogde T4 kan moonlik wees as gevolg van 'n estrogeniese effek en die verlaagde sperm konsentrasie weens 'n in utero en laktasie blootstelling. Die biologiese seltoetse het die teenwoordigheid van estrogeniese aktiwiteit in voerkrale se water bevestig. Die gevolge van die blootstelling van EOC mengsels op voortplantings-parameters bevestig die moontlikheid van EOC effek geassosieer met VGS. Verdere navorsing is nodig om die dosisresponsverhoudings van verskillende VGS te ondersoek. Copyright / Dissertation (MSc)--University of Pretoria, 2011. / School of Health Systems and Public Health (SHSPH) / Unrestricted

No description available.