Breeding for resistance becomes more and more important because we want to reduce the use of pesticides. A fast and cheap alternative can be to make use of morphological or chemical markers. In... Show moreBreeding for resistance becomes more and more important because we want to reduce the use of pesticides. A fast and cheap alternative can be to make use of morphological or chemical markers. In order to do so we first need to study resistance mechanism in plants and how they may change depending on environmental conditions or plant development. Based on these ideas we developed markers for thrips resistance in gladiolus. we showed that the density of papillae and chemical traits (triterpenoids and amino acids) are useful markers for breeding programs targeted at increased resistance in Gladiolus. Epicuticular papillae are easily detected since they are located at the leaves surface. The density of papillae is highly correlated with a number of metabolites that were associated with resistance. Concentrations of triterpenoid saponins, alanine and threonine were higher in resistant varieties. Therefore, papillae density and chemical compounds may provide an easy marker in Gladiolus breeding programs targeted at increased resistance against thrips. Concentrations of metabolites associated to thrips resistant remained constant during the ontogeny of the plant and under different growing conditions. These findings provide useful information for breeders because it implies that these markers can be determined in young plants and under different conditions. In dwarf gladiolus, Gladiolus nanus, also kaempferol was associated to resistance. However, it was only found in in plants grown in the climate chamber and not in plants grown under field conditions. Further studies will be needed to understand the mechanism of thrips resistance in Gladiolus in more detail. Show less
Freshwater eels (Anguilla spp.) intrigued scientists for centuries. Their life cycle involves for example two distinct larval stages and a long distance migration, which may cover thousands of... Show moreFreshwater eels (Anguilla spp.) intrigued scientists for centuries. Their life cycle involves for example two distinct larval stages and a long distance migration, which may cover thousands of kilometers. The farming of eels is still dependent on the influx of wild glass eels, because eels do not mature naturally in captivity due to strong neural inhibition. Since the 1980s, the glass eel influx of several eel species drastically declined. The European eel (A. anguilla) was recently enlisted by the IUCN as a critically endangered species; therefore there is an urgent call for eel management and artificial reproduction. Artificial reproduction may contribute to restoration of the eel population by releasing the current fishing pressures on the wild stocks, and allowing a sustainable eel aquaculture in the future. Although, artificial reproduction by applying hormone treatments is possible to some extent, success ra tes are still far from creating a sustainable aquaculture. This thesis focuses on the spawning migration, maturation and reproduction of eels. New tools are developed that may improve current artificial maturation and reproduction protocols for eel aquaculture. Show less
The maturation of UGT2B7-mediated drug glucuronidation was studied in preterm and term neonates up to infants of three years of age using a population approach. A pharmacokinetic model was... Show moreThe maturation of UGT2B7-mediated drug glucuronidation was studied in preterm and term neonates up to infants of three years of age using a population approach. A pharmacokinetic model was developed for morphine, which was used as a paradigm compound. In this model, the maturation of morphine glucuronidation is described by a bodyweight-based exponential relationship with an exponent of 1.44. The model-derived dosing algorithm was evaluated prospectively in a clinical trial and it was shown that this dosing algorithm may reduce overdosing of neonates and exposure to ineffective doses in older infants. Additionally, it was found that the bodyweight-based exponential relationship that describes the maturation of morphine glucuronidation can be directly applied to the maturation of zidovudine, which is also a UGT2B7 substrate. This expedites the development of paediatric pharmacokinetic models and evidence-based paediatric drug dosing algorithms. Based on a study using physiologically-based pharmacokinetic modeling it was concluded that the equation for maturation of morphine glucuronidation could be applicable to all small molecular drugs and to paediatric patient populations with normal hepatic function. Finally, a framework was developed to properly validate paediatric pharmacokinetic population models and the validation of paediatric pharmacokinetic models for morphine in literature were investigated. Show less
