@phdthesis{Rueppell2000,
  author    = {R{\"u}ppell, Olav},
  title     = {Queen size dimorphism in ants},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-1914},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2000},
  abstract  = {Many polymorphisms are linked to alternative reproductive strategies. In animals, this is particularly common in males. Ant queens are an important exception. The case of ant queen size dimorphisms has not been studied in sufficient detail, and thus this thesis aimed at elucidating causes and consequences of the different size of small (microgynous) and large (macrogynous)ant queens using the North American ant species Leptothorax rugatulus as a model system. Employing neutral genetic markers, no evidence for a taxonomically relevant separation of the gene pools of macrogynes and microgynes was found. Queens in polygynous colonies were highly related to each other, supporting the hypothesis that colonies with more than one queen commonly arise by secondary polygyny, i.e. by the adoption of daughter queens into their natal colonies. These results and conclusions are also true for the newly discovered queen size polymorphism in Leptothorax cf. andrei. Several lines of evidence favor the view that macrogynes predominantly found their colonies independently, while microgynes are specialized for dependent colony founding by readoption. Under natural conditions, mother and daughter size are highly correlated and this is also true for laboratory colonies. However, the size of developing queens is influenced by queens present in the colony. Comparing populations across the distribution range, it turns out that queen morphology (head width and ovariole number) is more differentiated among populations than worker morphology (coloration, multivariate size and shape), colony characteristics (queen and worker number per colony) or neutral genetic variation. Northern and southern populations differed consistently which indicates the possibility of two different species. The queen size dimorphism in L. rugatulus did neither influence the sex ratio produced by a colony, nor its ratio of workers to gynes. However, the sex ratio covaried strongly across populations with the average number of queens per colony in accordance with sex ratio theory. At the colony level, sex ratio could not be explained by current theory and a hypothesis at the colony-level was suggested. Furthermore, queen body size has no significant influence on the amount of reproductive skew among queens. Generally, the skew in L. rugatulus is low, and supports incomplete control models, rather than the classic skew models. In eight of fourteen mixed or microgynous colonies, the relative contributions of individual queens to workers, gynes and males were significantly different. This was mainly due to the fact that relative body size was negatively correlated with the ratio of gynes to workers produced. This supports the kin conflict over caste determination hypothesis which views microgyny as a selfish reproductive tactic.},
  subject      = {Ameisen},
  language  = {en}
}
@phdthesis{Lampert2001,
  author    = {Lampert, Kathrin P.},
  title     = {Alternative life history strategies in the West African reed frog, Hyperolius nitidulus},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-1677},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2001},
  abstract  = {Distinct juvenile behaviour differences, changes in adult sizes and reproductive capacity and a long reproductive period triggered the working hypothesis of two alternative life-cycle strategies favouring aestivation or immediate reproduction. The hypothesis for the life-cycles of Hyperolius nitidulus that differed from the commonly assumed reproductive strategy for this species was confirmed by the results of this study. Aestivated juveniles start to mature at the beginning of the rainy season and reproduce subsequently. Their tadpoles grow until metamorphosis and either reproduce in this same season, in which case their offspring aestivates (one year - two generations), or they delay reproduction to the following year and aestivate themselves (one year - one generation). Juveniles trying to reproduce as fast as possible will invest in growth and differentiation and show no costly adaptations to aestivation, while juveniles delaying reproduction to the following rainy season will be well adapted to dry season conditions. Indirect evidence for the existence of a second generation was found in all three investigation years: adult size decreased abruptly towards the end of the rainy season, mainly due to the arrival of very small individuals, and clutch size decreased abruptly. Also at the end of the rainy season juveniles had two behavioural types: one hiding on the ground and clearly avoiding direct sunlight and another sitting freely above ground showing higher tolerance towards dry season conditions (high air temperatures and low humidity). Skin morphology differed between the types showing many more purine crystals in a higher order in the dry-season adapted juveniles. The final proof for the existence of a second generation came with the recapture of individuals marked as juveniles when they left the pond. The 45 recaptured frogs definitely came back to the pond to reproduce during the same season in 1999. Second generation frogs (males and females) were significantly smaller than the rest of all adults and egg diameter was reduced. Clutch size did not differ significantly. It was found that females did not discriminate against second generation males when coming to the ponds to reproduce. Second generation males had a similar chance to be found in amplexus as first generation males. Indirect and direct evidence for a second generation matched very well. The sudden size decrease in adults occurred just at the time when the first marked frogs returned. The observation that freshly metamorphosed froglets were able to sit in the sun directly after leaving the water led to the assumption that the decision whether to aestivate or to reproduce already happens during the frogs' larval period. Water chemistry and the influence of light was investigated to look for the factors triggering the decision, but only contaminated water increased the number of juveniles ready for aestivation. Whether the life history polymorphism observed in Hyperolius nitidulus is due to phenotypic plasticity or genetic polymorphism is still not known. Despite this uncertainty, there is no doubt that the optimal combination of different life histories is profitable and may be a reason for the wide range and high local abundance of Hyperolius nitidulus.},
  subject      = {Westafrika},
  language  = {en}
}
@phdthesis{Endler2006,
  author    = {Endler, Annett},
  title     = {Regulation of reproductive division of labor in the ant Camponotus floridanus : behavioral mechanisms and pheromonal effects},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-18872},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2006},
  abstract  = {A hitherto unresolved problem is how workers are prevented from reproducing in large insect societies. The queen informs about her fertility and health which ensures sufficient indirect fitness benefits for workers. In the ant Camponotus floridanus, I found such a signal located on eggs of highly fertile queens. Groups of workers were regularly provided with different sets of brood. Only in groups with queen eggs workers refrain from reproducing. Thus, the eggs seem to inform the workers about queen presence. The signal on queen eggs is presumably the same that enables workers to distinguish between queen and worker-laid eggs, latter are destroyed by workers. Queen and worker-laid eggs differ in their surface hydrocarbons in a similar way as fertile queens differ from workers in the composition of their cuticular hydrocarbons. When I transferred hydrocarbons from the queen cuticle to worker eggs the eggs were no longer destroyed, indicating that they now carry the signal. These hydrocarbons thus represent a queen signal that regulates worker reproduction in this species. But the signal is not present in all fertile queens. Founding queens with low egg-laying rates differ in the composition of cuticular hydrocarbons from queens with high productivity. Similar differences in the composition of surface hydrocarbons were present on their eggs. The queen signal develops along with an increasing fertility and age of the queen, and this is perceived by the workers. Eggs from founding queens were destroyed like worker eggs. This result shows that founding queens lack the appropriate signal. In these little colony foundations chemical communication of queen status may not be necessary to prevent workers from reproducing, since workers may benefit more from investing in colony growth and increased productivity of large colonies rather than from producing male eggs in incipient colonies. If the queen is missing or the productivity of the queen decreases, workers start laying eggs. There is some evidence from correlative studies that, under queenless conditions, worker police each other because of differences in individual odors as a sign of social status. It can be expressed as either aggressive inhibition of ovarian activity, workers with developed ovaries are attacked by nest-mates, or destruction by worker-laid eggs. I found that in C. floridanus workers, in contrast to known studies, police only by egg eating since they are able to discriminate queen- and worker-laid eggs. Workers with developed ovaries will never attacked by nest-mates. This is further supported by qualitative and quantitative differences in the cuticular hydrocarbon profile of queens and workers, whereas profiles of workers with and without developed ovaries show a high similarity. I conclude that workers discriminate worker eggs on the basis of their hydrocarbon profile, but they are not able to recognize egg-laying nest-mates. Improving our knowledge of the proximate mechanisms of the reproductive division of labor in evolutionary derived species like C. floridanus will help to understand the evolution of extreme reproductive altruism involving sterility as a characteristic feature of advanced eusocial systems.},
  subject      = {Camponotus floridanus},
  language  = {en}
}
@phdthesis{Drescher2011,
  author    = {Drescher, Jochen},
  title     = {The Ecology and Population structure of the invasive Yelllow Crazy Ant Anoplolepis gracilipes},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-57332},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {The invasive Yellow Crazy Ant Anoplolepis gracilipes is a widespread tropical ant species which is particularly common in anthropogenically disturbed habitats in South-East Asia and the Indopacific region. Its native range is unknown, and there is little information concerning its social structure as a potential mechanism facilitating invasion as well as its ecology in one of the putative native ranges, South-East Asia. Using mitochondrial DNA sequences, I demonstrated that the majority of the current Indopacific colonies were likely introduced from South-East Asian populations, which in turn may have been introduced much earlier from a yet unidentified native range. By conducting behavioral, genetic and chemical analyses, I found that A. gracilipes supercolonies contain closely related individuals, thus resembling enlarged versions of monogynous, polydomous colonies of other ant species. Furthermore, mutually aggressive A. gracilipes supercolonies were highly differentiated both genetically and chemically, suggesting limited or even absent gene flow between supercolonies. Intranidal mating and colony-budding are most likely the predominant, if not the exclusive mode of reproduction and dispersal strategy of A. gracilipes. Consequently, a positive feedback between genetic, chemical and behavioral traits may further enhance supercolony differentiation though genetic drift and neutral evolution. This potential scenario led to the hypothesis that absent gene flow between different A. gracilipes supercolonies may drive them towards different evolutionary pathways, possibly including speciation. Thus, I examined one potential way by which gene flow between supercolonies of an ant species without nuptial flights may be maintained, i.e. the immigration of sexuals into foreign supercolonies. The results suggest that this option of maintaining gene flow between different supercolonies is likely impaired by severe aggression of workers towards allocolonial sexuals. Moreover, breeding experiments involving males and queens from different supercolonies suggest that A. gracilipes supercolonies may already be on the verge of reproductive isolation, which might lead to the diversification of A. gracilipes into different species. Regarding the ecological consequences of its potential introduction to NE-Borneo, I could show that A. gracilipes supercolonies may affect the local ant fauna. The ant community within supercolonies was less diverse and differed in species composition from areas outside supercolonies. My data suggest that the ecological dominance of A. gracilipes within local ant communities was facilitated by monopolization of food sources within its supercolony territory, achieved by a combination of rapid recruitment, numerical dominance and pronounced interspecific aggression. A. gracilipes' distribution is almost exclusively limited to anthropogenically altered habitat, such as residential and agricultural areas. The rate at which habitat conversion takes place in NE-Borneo will provide A. gracilipes with a rapidly increasing abundance of suitable habitats, thus potentially entailing significant population growth. An potentially increasing population size and ecological dominance, however, are not features that are limited to invasive alien species, but may also occur in native species that become 'pests' in an increasing abundance of anthropogenically altered habitat. Lastly, I detected several ant guests in supercolonies of A. gracilipes. I subsequently describe the relationship between one of them (the cricket Myrmecophilus pallidithorax) and its ant host. By conducting behavioral bioassays and analyses of cuticular hydrocarbon (CHC) profiles, I revealed that although M. pallidithorax is attacked and consumed by A. gracilipes whenever possible, it may evade aggression from its host by a combination of supreme agility and, possibly, chemical deception. This thesis adds to our general understanding of biological invasions by contributing species-specific data on a previously understudied invasive organism, the Yellow Crazy Ant Anoplolepis gracilipes. Introductions which may have occurred a long time ago may make it difficult to determine whether a given species is an introduced invader or a native pest species, as both may have pronounced ecological effects in native species communities. Furthermore, this thesis suggests that supercolonialism in invasive ants may not be an evolutionary dead end, but that it may possibly give rise to new species due to reproductive boundaries between supercolonies evoked by peculiar mating and dispersal strategies.},
  subject      = {Dem{\"o}kologie},
  language  = {en}
}
@phdthesis{Schuster2013,
  author    = {Schuster, Ruth},
  title     = {Die Auseinandersetzung um die moderne Fortpflanzungsmedizin in Deutschland und die Perspektiven des j{\"u}dischen Religionsgesetzes dazu},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-135701},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2013},
  abstract  = {Die Felder und Techniken der modernen Fortpflanzungsmedizin sind im Laufe der Jahre weit fortgeschritten. Um dem Wunsch eines kinderlosen Ehepaares nach Nachwuchs nachzugehen, haben sich Methoden entwickelt, um diesen zu erf{\"u}llen. Hierbei haben sich die In-Vitro-Fertilisation und die daraus entwickelte Modifikation, die Intracytoplasmatische Spermieninjektion etabliert. Auch wenn die seit dem Jahre 2004 durchgef{\"u}hrten IVF-Geburten, aufgrund mangelnder Krankenkassenleistungen, entschieden gesunken sind und die kumulative Schwangerschaftsrate nach drei durchgef{\"u}hrten Embryotransfers maximal bei 50-70 \% liegt, ist die In-Vitro-Fertilisation und mit ihr verwandten Intracytoplasmatischen Spermieninjektion (im Falle mangelnder Spermienqualit{\"a}t) neben der homologen und heterologen Insemination das {\"a}lteste und das neuste reproduktionsmedizinische Verfahren, das zur Behandlung des unerf{\"u}llten Kinderwunsches eingesetzt wird. Des Weiteren haben sich die Pr{\"a}implantations- und Pr{\"a}nataldiagnostik einen weit verbreiten Ruf verschafft, um Erbkrankheiten und Fehlentwicklungen des Embryos noch in fr{\"u}hester Entwicklungszeit aufzudecken. Dass hierbei der Embryo und das noch ungeborene Leben in eine Zwickm{\"u}hle ethischer und rechtlicher Beurteilungen rutschen, scheint offensichtlich. Denn das seit 1990 in Kraft getretene Embryonenschutzgesetz regelt zwar weite Bereiche rund um den Schutz des Embryos, hinterl{\"a}sst aber auch L{\"u}cken. Somit werden Rufe laut nach der Schaffung eines eigenen Fortpflanzungsmedizingesetzes, um die ungeregelten Aspekte der Fortpflanzungsmedizin zu kl{\"a}ren [457]. Die rechtliche Lage der modernen Fortpflanzungsmedizin in Deutschland ist recht komplex. F{\"u}r die vielen verschiedenen Methoden herrschen unterschiedlich rechtliche Regelungen. So wird zum Beispiel die In-Vitro-Fertilisation rechtlich anders geregelt als die Pr{\"a}natal- und die Pr{\"a}implantaionsdiagnostik. In Hinsicht auf die In-Vitro-Fertilisation dient als rechtliche Grundlage das Embryonenschutzgesetz, welches besagt, dass „bereits die befruchtete, entwicklungsf{\"a}hige menschliche Eizelle vom Zeitpunkt der Kernverschmelzung an" einem Embryo mit all seinen Rechten entspricht. Die Pr{\"a}nataldiagnostik st{\"u}tzt sich zum großen Teil auf die von der Bundes{\"a}rztekammer verabschiedeten „Richtlinien zur pr{\"a}natalen Diagnostik von Krankheiten und Krankheitsdispositionen" sowie auf eine „Erkl{\"a}rung zum Schwangerschaftsabbruch nach Pr{\"a}nataldiagnostik". In diesen Richtlinien wird darauf hingewiesen, dass zum einen das Lebensrecht des Ungeborenen, zum anderen die Handlungsfreiheit der Eltern in die jeweiligen Entscheidungen einbezogen werden muss. Die in Deutschland zwischen Zulassung und Nichtzulassung befindliche Pr{\"a}implantationsdiagnostik beruft sich auf das Embryonenschutzgesetz, welches den Verbrauch von Embryonen verbietet, da nach dem Gesetz eine Blastomere einem ganzen Embryo gleichgestellt sei. Ebenso besagt das ESchG, dass eine Eizelle nur zum Zweck der Herbeif{\"u}hrung einer Schwangerschaft befruchtet werden darf, da aber die Pr{\"a}implantationsdiagnostik die genetische Analyse beabsichtigt, steht dies in einem Widerspruch. Jedoch wird in und außerhalb von Europa der Umgang mit IVF, Pr{\"a}implantations- und Pr{\"a}nataldiagnostik verschieden gehandhabt. W{\"a}hrend sich Deutschland und {\"O}sterreich f{\"u}r ein klares Verbot der Pr{\"a}implantationsdiagnostik aussprechen, ist diese in Frankreich und Großbritannien grunds{\"a}tzlich m{\"o}glich. Wenn man sich die halachischen Grundlagen im Umgang mit der modernen Fortpflanzungsmedizin vor Augen f{\"u}hrt, ist es im Kern der Status des Embryos, der Juden und Christen in zwei v{\"o}llig verschiedene Richtungen laufen l{\"a}sst. Die Halacha spricht von menschlichem Leben erst von der Geburt an und geht von mehreren unterscheidbaren Stadien in der Entwicklung des vorgeburtlichen Lebens im Mutterleib aus. Ganz anders die christliche Ethik, sie erkennt bereits dem Embryo die Schutzw{\"u}rdigkeit menschlichen Lebens zu. Wenn das j{\"u}dische Recht die Schutzw{\"u}rdigkeit eines Embryos nach der entscheidenden Frage differenziert, ob er j{\"u}nger oder {\"a}lter als vierzig Tage ist, wird deutlich, dass die IVF als grunds{\"a}tzlich rechtm{\"a}ßig gelten muss, da die Embryonen, die im Zuge jeder IVF zerst{\"o}rt oder weitergehend genutzt werden, keinen besonderen Schutz in Anspruch nehmen k{\"o}nnen. Ebenso fallen jene Vorg{\"a}nge und Maßnahmen einer modernen PID in jenen Zeitraum von vierzig Tagen nach der Empf{\"a}ngnis, innerhalb dessen nach jahrtausendalter Einstellung des j{\"u}dischen Rechts noch kein menschliches Leben im Mutterleib existiert. Somit steht die Halacha einer begr{\"u}ndeten PID nicht im Wege. Eine zweite große Kernaussage dieser Dissertation ist die, dass sich das j{\"u}dische Religionsgesetz (die Halacha), welche unter anderem die Anleitungen zum Umgang mit der modernen Reproduktionsmedizin liefert, stets darauf bedacht ist, neu ausgelegt zu werden. Die Halacha ist ein immerw{\"a}hrend andauernder Prozess von Erneuerung, welche sich den aktuellen und {\"o}rtlichen Gegebenheiten kritisch anpassen muss. So auch der Umgang mit der modernen Fortpflanzungsmedizin, der einem immerw{\"a}hrenden Prozess von Erneuerungen unterlegen ist.},
  subject      = {Reproduktionsmedizin},
  language  = {de}
}
@phdthesis{Schuster2013,
  author    = {Schuster, Ruth},
  title     = {Die Auseinandersetzung um die moderne Fortpflanzungsmedizin in Deutschland und die Perspektiven des j{\"u}dischen Religionsgesetzes dazu},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-92822},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2013},
  abstract  = {Die Felder und Techniken der modernen Fortpflanzungsmedizin sind im Laufe der Jahre weit fortgeschritten. Um dem Wunsch eines kinderlosen Ehepaares nach Nachwuchs nachzugehen, haben sich Methoden entwickelt, um diesen zu erf{\"u}llen. Hierbei haben sich die In-Vitro-Fertilisation und die daraus entwickelte Modifikation, die Intracytoplasmatische Spermieninjektion etabliert. Auch wenn die seit dem Jahre 2004 durchgef{\"u}hrten IVF-Geburten, aufgrund mangelnder Krankenkassenleistungen, entschieden gesunken sind und die kumulative Schwangerschaftsrate nach drei durchgef{\"u}hrten Embryotransfers maximal bei 50-70 \% liegt, ist die In-Vitro-Fertilisation und mit ihr verwandten Intracytoplasmatischen Spermieninjektion (im Falle mangelnder Spermienqualit{\"a}t) neben der homologen und heterologen Insemination das {\"a}lteste und das neuste reproduktionsmedizinische Verfahren, das zur Behandlung des unerf{\"u}llten Kinderwunsches eingesetzt wird. Des Weiteren haben sich die Pr{\"a}implantations- und Pr{\"a}nataldiagnostik einen weit verbreiten Ruf verschafft, um Erbkrankheiten und Fehlentwicklungen des Embryos noch in fr{\"u}hester Entwicklungszeit aufzudecken. Dass hierbei der Embryo und das noch ungeborene Leben in eine Zwickm{\"u}hle ethischer und rechtlicher Beurteilungen rutschen, scheint offensichtlich. Denn das seit 1990 in Kraft getretene Embryonenschutzgesetz regelt zwar weite Bereiche rund um den Schutz des Embryos, hinterl{\"a}sst aber auch L{\"u}cken. Somit werden Rufe laut nach der Schaffung eines eigenen Fortpflanzungsmedizingesetzes, um die ungeregelten Aspekte der Fortpflanzungsmedizin zu kl{\"a}ren [457]. Die rechtliche Lage der modernen Fortpflanzungsmedizin in Deutschland ist recht komplex. F{\"u}r die vielen verschiedenen Methoden herrschen unterschiedlich rechtliche Regelungen. So wird zum Beispiel die In-Vitro-Fertilisation rechtlich anders geregelt als die Pr{\"a}natal- und die Pr{\"a}implantaionsdiagnostik. In Hinsicht auf die In-Vitro-Fertilisation dient als rechtliche Grundlage das Embryonenschutzgesetz, welches besagt, dass „bereits die befruchtete, entwicklungsf{\"a}hige menschliche Eizelle vom Zeitpunkt der Kernverschmelzung an" einem Embryo mit all seinen Rechten entspricht. Die Pr{\"a}nataldiagnostik st{\"u}tzt sich zum großen Teil auf die von der Bundes{\"a}rztekammer verabschiedeten „Richtlinien zur pr{\"a}natalen Diagnostik von Krankheiten und Krankheitsdispositionen" sowie auf eine „Erkl{\"a}rung zum Schwangerschaftsabbruch nach Pr{\"a}nataldiagnostik". In diesen Richtlinien wird darauf hingewiesen, dass zum einen das Lebensrecht des Ungeborenen, zum anderen die Handlungsfreiheit der Eltern in die jeweiligen Entscheidungen einbezogen werden muss. Die in Deutschland zwischen Zulassung und Nichtzulassung befindliche Pr{\"a}implantationsdiagnostik beruft sich auf das Embryonenschutzgesetz, welches den Verbrauch von Embryonen verbietet, da nach dem Gesetz eine Blastomere einem ganzen Embryo gleichgestellt sei. Ebenso besagt das ESchG, dass eine Eizelle nur zum Zweck der Herbeif{\"u}hrung einer Schwangerschaft befruchtet werden darf, da aber die Pr{\"a}implantationsdiagnostik die genetische Analyse beabsichtigt, steht dies in einem Widerspruch. Jedoch wird in und außerhalb von Europa der Umgang mit IVF, Pr{\"a}implantations- und Pr{\"a}nataldiagnostik verschieden gehandhabt. W{\"a}hrend sich Deutschland und {\"O}sterreich f{\"u}r ein klares Verbot der Pr{\"a}implantationsdiagnostik aussprechen, ist diese in Frankreich und Großbritannien grunds{\"a}tzlich m{\"o}glich. Wenn man sich die halachischen Grundlagen im Umgang mit der modernen Fortpflanzungsmedizin vor Augen f{\"u}hrt, ist es im Kern der Status des Embryos, der Juden und Christen in zwei v{\"o}llig verschiedene Richtungen laufen l{\"a}sst. Die Halacha spricht von menschlichem Leben erst von der Geburt an und geht von mehreren unterscheidbaren Stadien in der Entwicklung des vorgeburtlichen Lebens im Mutterleib aus. Ganz anders die christliche Ethik, sie erkennt bereits dem Embryo die Schutzw{\"u}rdigkeit menschlichen Lebens zu. Wenn das j{\"u}dische Recht die Schutzw{\"u}rdigkeit eines Embryos nach der entscheidenden Frage differenziert, ob er j{\"u}nger oder {\"a}lter als vierzig Tage ist, wird deutlich, dass die IVF als grunds{\"a}tzlich rechtm{\"a}ßig gelten muss, da die Embryonen, die im Zuge jeder IVF zerst{\"o}rt oder weitergehend genutzt werden, keinen besonderen Schutz in Anspruch nehmen k{\"o}nnen. Ebenso fallen jene Vorg{\"a}nge und Maßnahmen einer modernen PID in jenen Zeitraum von vierzig Tagen nach der Empf{\"a}ngnis, innerhalb dessen nach jahrtausendalter Einstellung des j{\"u}dischen Rechts noch kein menschliches Leben im Mutterleib existiert. Somit steht die Halacha einer begr{\"u}ndeten PID nicht im Wege. Eine zweite große Kernaussage dieser Dissertation ist die, dass sich das j{\"u}dische Religionsgesetz (die Halacha), welche unter anderem die Anleitungen zum Umgang mit der modernen Reproduktionsmedizin liefert, stets darauf bedacht ist, neu ausgelegt zu werden. Die Halacha ist ein immerw{\"a}hrend andauernder Prozess von Erneuerung, welche sich den aktuellen und {\"o}rtlichen Gegebenheiten kritisch anpassen muss. So auch der Umgang mit der modernen Fortpflanzungsmedizin, der einem immerw{\"a}hrenden Prozess von Erneuerungen unterlegen ist.},
  subject      = {Reproduktionsmedizin},
  language  = {de}
}
@phdthesis{vonMeyer2021,
  author    = {von Meyer, Katharina},
  title     = {Molecular characterization of defensin-like proteins in the fertilization process of \(Nicotiana\) \(tabacum\)},
  doi       = {10.25972/OPUS-19214},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-192141},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2021},
  abstract  = {Flowering plants or angiosperms have developed a fertilization mechanism that involves a female egg and central cell, as well as two male sperm cells. A male gametophyte carries the two non-mobile sperm cells, as they need to be delivered to the female gametophyte, the embryo sac. This transport is initiated by a pollen grain that is transmitted onto the stigma of the angiosperm flower. Here it hydrates, germinates, and forms a pollen tube, which navigates through the female plant tissue towards the ovary. The pollen tube grows into an ovule through the funiculus and into one of the two synergid cells. There, growth arrests and the pollen tube bursts, releasing the two sperm cells. One of the sperm cells fuses with the egg cell, giving rise to the embryo, the other one fuses with the central cell, developing into the endosperm, which nourishes the embryo during its development. After a successful fertilization, each ovule develops into a seed and a fruit is formed. This usually consists of several fertilized ovules. The directional growth of the pollen tube through the maternal tissues towards the ovule, as well as sperm cell release, requires a complex communication between the male and the female gametophyte to achieve reproductive success. Over the last years many studies have been performed, contributing to the understanding of cell-cell communication events between the two gametophytes, nevertheless still many aspects remain to be elucidated. This work focused on two topics: i.) Analysis of biological processes affected by pollination and fertilization in the Nicotiana tabacum flower and identification of cysteine rich proteins (CRPs) expressed via isolating and sequencing RNA from the tissue and analyzing the resulting data. ii.) Identification of the defensin-like protein (DEFL) responsible for pollen tube attraction towards the ovule in tobacco. First, tissue samples of pollen tubes and mature ovules were taken at different stages of the fertilization process (unpollinated ovules, after pollination, and after fertilization of the flower). RNA was then isolated and a transcriptome was created. The resulting reads were assembled and transcriptome data analysis was performed. Results showed that pollen tubes and mature ovules differ severely from each other, only sharing about 23 \% of the transcripts, indicating that different biological processes are dominant in the two gametophytes. A MapMan analysis revealed that in the pollen tube the most relevant biological processes are related to the cell wall, signaling, and transport, which supports the fact that the pollen tube grows fast to reach the ovule. On the other hand, in the ovule the values of highest significance were obtained for processes related to protein synthesis and regulation. Upon comparing the transcripts in the ovule before and after pollination, as well as after fertilization, it showed that pollination of the flower causes a bigger alteration in the ovule on the transcriptomic level compared to the step from pollination to fertilization. A total of 953 CRPs were identified in Nicotiana tabacum, including 116 DEFLs. Among those, the peptide responsible for pollen tube attraction towards the ovule should be found. Based on in-silico analysis four candidate peptides were chosen for further analysis, two of which had increased expression levels upon pollination and fertilization and the other two displayed an opposite expression. Quantitative real time PCR experiments were performed for the candidates, confirming the in-silico data in vivo. The candidate transcripts were then expressed in a cell free system and applied to pollen tubes in order to test their effect on the growing cells. Positive controls were used, where pollen tubes grew towards freshly dissected ovules. The four candidates did not provoke a pollen tube attraction towards the peptide, leaving open the chance to work on the 112 remaining DEFLs in the future.},
  subject      = {Samenpflanzen},
  language  = {en}
}