Anpassungsprozesse in der Frühentwicklung von Weizenpopulationen über 11 Generationen an das Anbausystem

Eine wichtige Anpassung an den ökologischen Anbau ist eine zügige Frühentwicklung und ein Wurzelsystem, das an organische Düngung angepasst ist. Eine Halbdiallelkreuzung aus insgesamt 20 europäischen Winterweizensorten wurde 2001 hergestellt und insgesamt drei Subpopulationen aus neun Hochertragseltern (CY), eine mit 12 Backqualitätseltern (CQ) und eine aus allen Eltern (CYQ) zusammengestellt. Seit der F5 wird Saatgut unter konventionellen und ökologischen Anbaubedingungen in jeweils zwei parallelen Populationen getrennt nachgebaut. Saat jeder Generation wird bei -20o C aufbewahrt. Für die Versuche wurden Generationen F6, F10, F11, F15 in einem Feld zu F6.1, F10.1, F11.1, F15.1 vermehrt. Frisches Saatgut wurde im Hydrokultursystem zwei Wochen bei 18/12 oC (Tag/Nacht) angebaut und die Wurzel- und Sproßlängen und Gewichte gemessen. Von der F6.1 zur F15.1 verlängerten sich die Seminalwurzeln unter ökologischen aber nicht unter konventionellen Bedingungen signifikant. Eine Ausnahme stellt die F11.1 Generation dar, die in der F11 extremem Kahlfrost durchlitten hatte und unter beiden Anbaubedingungen deutlich kürzere Wurzeln produzierte als ein Jahr zuvor oder vier Jahre später. Die Seminalwurzellänge in den konventionell angebauten Y CCPs signifikant kürzer als in den ökologisch angebauten. Im Gegensatz dazu unterschieden sich die Q Populationen nicht, während sich die YQ Populationen unter ökologischen Bedingungen wie die Q CCPs verhielten, unter konventionellen Bedingungen aber eine Zwischenposition zwischen Y und Q einnahmen. Insgesamt nahmen die Sproßlängen in allen Populationen leicht zu in den ersten vier Generationen und blieben danach gleich. Die CCPs zeigen auch nach 15 Generationen konsistent ihre ursprünglichen genetischen Unterschiede. Der Nachbau in großen Parzellen kann die genetische Breite der CCPs auch durch einmaligen Extremereignisse grundsätzlich erhalten

Scalable Preparation and Differential Pharmacologic and Toxicologic Profiles of Primaquine Enantiomers

Hematotoxicity in individuals genetically deficient in glucose-6-phosphate dehydrogenase (G6PD) activity is the major limitation of primaquine (PQ), the only antimalarial drug in clinical use for treatment of relapsing Plasmodium vivax malaria. PQ is currently clinically used in its racemic form. A scalable procedure was developed to resolve racemic PQ, thus providing pure enantiomers for the first time for detailed preclinical evaluation and potentially for clinical use. These enantiomers were compared for antiparasitic activity using several mouse models and also for general and hematological toxicities in mice and dogs. (+)-(S)-PQ showed better suppressive and causal prophylactic activity than (−)-(R)-PQ in mice infected with Plasmodium berghei. Similarly, (+)-(S)-PQ was a more potent suppressive agent than (−)-(R)-PQ in a mouse model of Pneumocystis carinii pneumonia. However, at higher doses, (+)-(S)-PQ also showed more systemic toxicity for mice. In beagle dogs, (+)-(S)-PQ caused more methemoglobinemia and was toxic at 5 mg/kg of body weight/day given orally for 3 days, while (−)-(R)-PQ was well tolerated. In a novel mouse model of hemolytic anemia associated with human G6PD deficiency, it was also demonstrated that (−)-(R)-PQ was less hemolytic than (+)-(S)-PQ for the G6PD-deficient human red cells engrafted in the NOD-SCID mice. All these data suggest that while (+)-(S)-PQ shows greater potency in terms of antiparasitic efficacy in rodents, it is also more hematotoxic than (−)-(R)-PQ in mice and dogs. Activity and toxicity differences of PQ enantiomers in different species can be attributed to their different pharmacokinetic and metabolic profiles. Taken together, these studies suggest that (−)-(R)-PQ may have a better safety margin than the racemate in human

Genotoxicity of metal oxide nanomaterials: review of recent data and discussion of possible mechanisms

Nanotechnology has rapidly entered into human society, revolutionized many areas, including technology, medicine and cosmetics. This progress is due to the many valuable and unique properties that nanomaterials possess. In turn, these properties might become an issue of concern when considering potentially uncontrolled release to the environment. The rapid development of new nanomaterials thus raises questions about their impact on the environment and human health. This review focuses on the potential of nanomaterials to cause genotoxicity and summarizes recent genotoxicity studies on metal oxide/silica nanomaterials. Though the number of genotoxicity studies on metal oxide/silica nanomaterials is still limited, this endpoint has recently received more attention for nanomaterials, and the number of related publications has increased. An analysis of these peer reviewed publications over nearly two decades shows that the test most employed to evaluate the genotoxicity of these nanomaterials is the comet assay, followed by micronucleus, Ames and chromosome aberration tests. Based on the data studied, we concluded that in the majority of the publications analysed in this review, the metal oxide (or silica) nanoparticles of the same core chemical composition did not show different genotoxicity study calls (i.e. positive or negative) in the same test, although some results are inconsistent and need to be confirmed by additional experiments. Where the results are conflicting, it may be due to the following reasons: (1) variation in size of the nanoparticles; (2) variations in size distribution; (3) various purities of nanomaterials; (4) variation in surface areas for nanomaterials with the same average size; (5) differences in coatings; (6) differences in crystal structures of the same types of nanomaterials; (7) differences in size of aggregates in solution/media; (8) differences in assays; (9) different concentrations of nanomaterials in assay tests. Indeed, due to the observed inconsistencies in the recent literature and the lack of adherence to appropriate, standardized test methods, reliable genotoxicity assessment of nanomaterials is still challenging