Refine
Has Fulltext
- yes (67)
Is part of the Bibliography
- yes (67)
Year of publication
- 2011 (67) (remove)
Document Type
- Journal article (42)
- Doctoral Thesis (24)
- Master Thesis (1)
Language
- English (67) (remove)
Keywords
- Biene (5)
- Ameisen (3)
- Memory (3)
- Taufliege (3)
- Behavior (2)
- Biology (2)
- Cancer (2)
- DNA (2)
- Drosophila (2)
- Drosophila melanogaster (2)
- Fusion proteins (2)
- Gedächtnis (2)
- Learning (2)
- Lernen (2)
- Maus (2)
- Olfaction (2)
- Olfaktion (2)
- PALM (2)
- Pilzkörper (2)
- Proteine (2)
- Stachellose Biene (2)
- Stammzelle (2)
- Trypanosoma brucei (2)
- Verhalten (2)
- antennal lobe (2)
- dSTORM (2)
- differentiation (2)
- fluorescent proteins (2)
- mushroom body (2)
- photoswitchable organic fluorophores (2)
- super-resolution (2)
- 26S RDNA Data (1)
- AFLP (1)
- ALBA Proteine (1)
- ALBA proteins (1)
- Abwehr (1)
- Actin (1)
- Activation (1)
- Adenocarcinomas (1)
- African Trypanosomes (1)
- Aktin (1)
- Allelic loss (1)
- Allergie (1)
- Alter (1)
- Alzheimerkrankheit (1)
- Amazonian forest (1)
- Ameisengäste (1)
- Amplification (1)
- Anoplolepis gracilipes (1)
- Ant-following birds (1)
- Antennallobus (1)
- Antibody (1)
- Apis mellifera (1)
- Apoptosis (1)
- Aquaculture (1)
- Aquakultur (1)
- Araneae (1)
- Asisted Reproduction (1)
- Assemblages (1)
- Assoziatives Gedächtnis (1)
- Asthma (1)
- Attraction (1)
- Attraktion (1)
- B chromosomes (1)
- Bacillus-subtilis (1)
- Barcodes (1)
- Benin (1)
- Bestäubung (1)
- Bienenbrut (1)
- Bienenkrankheit (1)
- Biodiversität (1)
- Bioinformatik (1)
- Biological Invasions (1)
- Biological identifications (1)
- Biologie (1)
- Blattschneiderameisen (1)
- Blood-brain-barrier (1)
- Bone morphogenetic protein-2 (1)
- Bronchialasthma (1)
- Brownsche Bewegung (1)
- Brucei (1)
- Brustkrebs (1)
- Bt-Mais (1)
- Bt-maize (1)
- CYR61 (1)
- Carnica-Biene (1)
- Cataglyphis (1)
- Cataglyphis-fortis (1)
- Cell Motility (1)
- Cell surface (1)
- Cell-line (1)
- Central complex (1)
- Chemotaxis (1)
- Children (1)
- Chlamydia pneumoniae (1)
- Chlamydiales (1)
- Clarias gariepinus (1)
- Cognition (1)
- Coleoptera (1)
- Colonial volvocales chlorophyta (1)
- Components (1)
- Conservation (1)
- Counting (1)
- CrossQuery (1)
- Cyclo-AMP (1)
- Cytologie (1)
- DNA barcodes (1)
- DNA recombination (1)
- Dasycladales chlorophyta (1)
- Demökologie (1)
- Desert ant navigation (1)
- Differenzierung (1)
- Diffusionsgewichtete Bildgebung (1)
- Dorylinae (1)
- Drosophila Antennal Lobe (1)
- Drosophila Larva (1)
- Drosophila Larve (1)
- EGF (1)
- EGF Rezeptor (1)
- EGFR Transactivation (1)
- Edema formation (1)
- Embryo (1)
- Entwicklung (1)
- Environmental Risk Assessment (1)
- Epidermaler Wachstumsfaktor (1)
- Epidermaler Wachstumsfaktor-Rezeptor (1)
- Epigenetics (1)
- Epigenotypus (1)
- Epimutation (1)
- European beech (1)
- Evolution (1)
- Experimental intracerebral hemorrhage (1)
- Extensivtierhaltung (1)
- FLAMM (1)
- Factor sigma(B) (1)
- Fische (1)
- Flagellum (1)
- Fluorescence microscopy (1)
- Formicidae (1)
- Fortpflanzung (1)
- Functional diversity (1)
- Funktionelle NMR-Tomographie (1)
- G-Protein gekoppelte Rezeptoren (1)
- GAG (1)
- GPCR (1)
- Gehirn (1)
- Genanalyse (1)
- Gene-expression (1)
- Genetik (1)
- Genexpression (1)
- Genome Sequencing (1)
- Genomsequenzierung (1)
- Geruch (1)
- Geruchssinn (1)
- Geruchswahrnehmung (1)
- Geschlecht (1)
- Gesicht (1)
- Gram-positive bacteria (1)
- Habitat fragmentation (1)
- Heparan-sulfate (1)
- Hippocampus (1)
- Honey bee (1)
- Honey-bees (1)
- Honeybee (1)
- Honigbiene (1)
- Human lung-cancer (1)
- Human-immunodeficiency-virus (1)
- Hypersensibilität (1)
- IN-VIVO (1)
- Imaging (1)
- Imidacloprid (1)
- Imprinting (1)
- In vivo (1)
- In-vivo (1)
- Induced senescence (1)
- Informationsverarbeitung (1)
- Insektenlarve (1)
- Interaktion (1)
- Intrazellulärer Transport (1)
- Invasionsbiologie (1)
- Invasive Art (1)
- Ischemia (1)
- Ischemie (1)
- K-RAS (1)
- Keimzell- und Embryonalentwicklung (1)
- Kinase pathway (1)
- Kognition (1)
- Kognitives Lernen (1)
- Kohlenstoff (1)
- Kontrolle der Genexpression (1)
- Korrelation (1)
- Krebs (1)
- Krebs <Medizin> (1)
- LINC complex (1)
- Land plants (1)
- Land-use change (1)
- Landschaft (1)
- Landwirtschaft (1)
- Langzeitpotenzierung (1)
- Larve (1)
- Ligand <Biochemie> (1)
- Limit (1)
- Listeria monocytogenes (1)
- Live cells (1)
- Living cells (1)
- Logged forests (1)
- Long-term potentiation (1)
- Lov domain (1)
- Lung-cancer (1)
- MRI (1)
- Madagascar (1)
- Magnetic-resonance microscopy (1)
- Maus Modell (1)
- Mechanisms (1)
- Medizin (1)
- Melophorus-bagoti (1)
- Metalloprotease (1)
- Microarray data (1)
- Middle cerebral-artery (1)
- Mikroglomeruli (1)
- Model (1)
- Molecular systematics (1)
- Molecules (1)
- Monoklonaler Antikörper (1)
- Monte-Carlo-Simulation (1)
- Morphing (1)
- Motion (1)
- Mouse-brain (1)
- Movement (1)
- Mushroom bodies (1)
- Mutation (1)
- Myofibroblast differentiation (1)
- N-Myc (1)
- NMR-Bildgebung (1)
- NMR-Tomographie (1)
- NTP-binding-properties (1)
- Nahrungserwerb (1)
- Nanoröhre (1)
- Navigation (1)
- Nervenfaser (1)
- Netzwerkanalyse (1)
- Neuro-blastoma (1)
- Neuroethologie (1)
- Neurogenetics (1)
- Neurogenetik (1)
- Nichtzielorganismen (1)
- Non-phototrophic bacteria (1)
- Non-target effects (1)
- Nosema (1)
- Nosema apis (1)
- Nuclear RDNA (1)
- P53 (1)
- PEDF (1)
- Parasit (1)
- Parataxonomy (1)
- Partially parallel acquisitions (1)
- Path-integraton (1)
- Patterns (1)
- Photoactivated localization microscopy (1)
- Plantation forests (1)
- Plasma-membrane (1)
- Plastizität (1)
- Pluripotent stem cells (1)
- Pluripotenz (1)
- Population structure (1)
- Populationsstruktur (1)
- Prfa-mediated virulence (1)
- Profile distances (1)
- Proliferation (1)
- Prunus-africana (1)
- RBCL Gene-sequences (1)
- RFID (1)
- Rain-forest (1)
- Random-Walk (1)
- Rat spinal-cord (1)
- Ratte (1)
- Real-time (1)
- Receptor (1)
- Receptor ytva (1)
- Recurrent neural-networks (1)
- Reinforcement (1)
- Reproduktionsmedizin (1)
- Retroviren (1)
- Rotbuche (1)
- Räumliches Gedächtnis (1)
- SUN domain protein (1)
- Schlaganfall (1)
- Secondary structure (1)
- Seed dispersal (1)
- Serum autoantibodies (1)
- Sigma(B)-dependent stress-response (1)
- Smooth-muscle-cells (1)
- Soziale Insekten (1)
- Species richness (1)
- Speicher (1)
- Spinnen (1)
- Sprouting angiogenesis (1)
- Squalius alburnoides (1)
- Stimulated-emission (1)
- Stress (1)
- Stroke (1)
- Subitizing (1)
- Sun1 (1)
- Super-Resolution Microscopy (1)
- Suppressors EXT1 (1)
- Switch (1)
- Synapse (1)
- Synaptische Plastizität (1)
- Systematic search (1)
- TGF-beta (1)
- TYPE-1 (1)
- Taxonomy (1)
- Therapy (1)
- Tierökologie (1)
- Time (1)
- Toll-like Rezeptor (1)
- Toll-like receptor (1)
- Transaktivierung (1)
- Transkriptionsfaktor (1)
- Trophobiose (1)
- Trypanosome (1)
- Trypanosomen (1)
- Tsetse Fliege (1)
- Tsetsefliege (1)
- UV (1)
- Umwelttoxikologie (1)
- Universitätsforst Würzburg (1)
- VASP (1)
- VSG (1)
- Vaccinia Virus (1)
- Vasodilatator-stimuliertes Phosphoprotein (1)
- Verhaltenplastizität (1)
- Verhaltensforschung (1)
- Verteidigung (1)
- Vesikeltransport (1)
- Visuelles Gedächtnis (1)
- Visuelles System (1)
- Wernicke's perpendicular fasciculus (1)
- Wernickes Assoziationsbündel (1)
- Whedos (1)
- White-matter (1)
- Wilms tumor (1)
- Wirkstoff (1)
- Würzburg University Forest (1)
- Yellow Crazy Ant (1)
- Yersinia enterocolitica (1)
- Zelldifferenzierung (1)
- Zoologie (1)
- Zählen (1)
- allergy (1)
- ant (1)
- antigen processing and recognition (1)
- ants (1)
- asexual reproduction (1)
- assistierte Reproduktion (1)
- autofluorescence (1)
- behavioral change (1)
- behavioral maturation (1)
- biodiversity (1)
- bioinformatics (1)
- brood development (1)
- cameleon (1)
- cancer stem cells (1)
- clothianidin (1)
- comparative genomics (1)
- coumaphos (1)
- cyclic nucleotide signaling (1)
- defense (1)
- diet (1)
- differential geneexpression (1)
- differenzielle Genexpression (1)
- diffusion tractography (1)
- drosophila melanogaster (1)
- ecological process (1)
- extensive Fischerei-Systeme (1)
- extensive fishery (1)
- face morphing (1)
- facial age (1)
- facial gender (1)
- flagellar sensing proteins (1)
- functional MRI (1)
- functional modules (1)
- funktionelle Module (1)
- gel electrophoresis (1)
- gene expression control (1)
- gene flow (1)
- genetically modified crops (1)
- genetically modified plants (1)
- genomic databases (1)
- glomerulus (1)
- gynogenesis (1)
- hippocampus (1)
- homologous recombination (1)
- honey bee (1)
- honey bees (1)
- honeybee (1)
- human breast cancer (1)
- hybridomas (1)
- imidacloprid (1)
- immunohistochemistry techniques (1)
- immunoprecipitation (1)
- insect pests (1)
- insects (1)
- interaction (1)
- interspecific comparison (1)
- introgression (1)
- isoform (1)
- larvae (1)
- learning and memory (1)
- macroglomerulus (1)
- maize (1)
- map (1)
- melanogaster (1)
- meningococcal disease (1)
- microdissection (1)
- microglomeruli (1)
- microsatellites (1)
- monoclonal antibodies (1)
- monoklonale Antikörper (1)
- mouse (1)
- mouse model (1)
- mtDNA (1)
- nanobiocomposites (1)
- neisseria meningitidis (1)
- nephroblastoma (1)
- networkanalysis (1)
- neurons (1)
- neuropil (1)
- nuclear envelope (1)
- olfaction (1)
- olfactory glomeruli (1)
- olfactory information (1)
- organization (1)
- parasite cycle (1)
- parasitärer Entwicklungszyklus (1)
- paternal introgression (1)
- plasticity (1)
- pollen (1)
- population genetics (1)
- primary tumor cell culture (1)
- radiofrequency identification (1)
- rat (1)
- recombinant proteins (1)
- resin (1)
- retinoic acid (1)
- retroviral proteins (1)
- reveals (1)
- silico model (1)
- silver staining (1)
- spatial representation (1)
- stingless bees (1)
- synaptic plasticity (1)
- synaptic proteins (1)
- synaptische Proteine (1)
- telomeres (1)
- transcription factors (1)
- trypanosomes (1)
- tsetse fly (1)
- tumor model (1)
- unicellular cyanobacteria (1)
- vaccinia virus (1)
- variability analysis (1)
- vesicle transport (1)
- virale Proteine (1)
- Öko-Toxikologie (1)
- Ökologische Prozesse (1)
Institute
- Theodor-Boveri-Institut für Biowissenschaften (67) (remove)
Sonstige beteiligte Institutionen
EU-Project number / Contract (GA) number
- 226852 (1)
The Ecology and Population structure of the invasive Yelllow Crazy Ant Anoplolepis gracilipes
(2011)
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.
In the last decades, both the incidence and the severity of asthma have steadily increased. Furthermore, available therapies only treat the symptoms but do not cure the disease. Immune modulation induced by TLR agonists may be a promising novel approach to effectively treat asthma as it targets the underlying immunopathology directly rather than one mediator alone. The aim of this thesis was to investigate if the immunostimulatory properties of Toll-like receptor (TLR) agonists can be utilized to develop novel therapeutic intervention strategies for the treatment of asthma using murine models of allergic inflammation. For this purpose five different TLR agonists were tested in preclinical mouse models of acute and chronic asthma, both in preventive and therapeutic settings. Firstly, TLR-2, 3, 4, 7/8 and 9 agonists were delivered intratracheally at different doses before pulmonary allergen exposure in the asthma model of acute inflammation. TLR9 agonist CpG-containing oligodeoxynucleotides (CpG) > TLR7 agonist Resiquimod (R848) > TLR3 agonists poly(I:C) strongly reduced allergen induced airway eosinophilia and IL-4 levels in a dose-dependent manner. All TLR agonists increased neutrophil numbers, TLR4 agonist lipopolysaccharide (LPS) > TLR2 agonist lipoteichonic acid (LTA) > poly(I:C) > CpG > R848 and, with the exception of R848, the amount of pro-inflammatory cytokines in the airways. Suppressive effects were not dependent upon IFN-γ and IL-10 or associated with increased numbers of regulatory T cells in the airways. All TLR agonists, except LTA, similarly reduced airway eosinophilia and IL-4 levels when applied therapeutically after allergen challenge. These results show that the TLR agonists have different suppressive effects on TH2 responses in the airways which further depend on the dose and the experimental setup in which they were tested. Interestingly, all agonists induced airway neutrophilia, albeit to different degrees, raising the question if TLR ligands are safe for human use when applied directly into the lung. Different TLR agonists are also being developed for human use as adjuvants combined with allergen in specific immunotherapy. Recent clinical data suggest that this may be achieved by induction of allergen-specific TH1 responses. For this reason, the ability of different TLR agonists to induce allergen-specific TH1 and suppress allergen-specific TH2 responses in a preclinical setting was investigated in this thesis. Different doses of the TLR agonists were applied together with allergen, then mice were exposed to allergen aerosol. CpG > LPS >LTA dose-dependently strongly suppressed the development of airway eosinophilia with poly(I:C) and R848 having no effect. The decrease in eosinophilic numbers was associated withincreased neutrophils present in the airways. IL-4 and IL-5 levels in the bronchoalveolar lavage fluid were also decreased when poly(I:C), LPS, and CpG were used. All TLR agonists increased allergen-specific IgG2a, and with the exception of poly(I:C), reduced allergen-specific IgE levels in the serum. Cutaneous anaphylaxis to allergen was completely prevented when LPS or CpG were given as adjuvant. The strongest TH1 responses were induced by CpG and poly(I:C), characterized by the presence of IFN-γ in the bronchoalveolar lavage and the highest allergen-specific IgG2a levels in the serum. This data supports approaches to use TLR9 or TLR4 agonists for human therapy as adjuvant in combination with allergen in novel specific immunotherapy formulations. In the last part of the thesis, it was investigated if TLR activation can also affect the pathology of severe chronic asthma. Therapeutic administration of R848 or CpG reduced features of inflammation and remodeling. Both agonists showed superior effects to dexamethasone, with CpG being more efficient than R848. This result again supports a TLR9-based therapy as a viable option for the treatment of severe chronic asthma which may present a potential alternative for anti-inflammatory therapy with steroids. Taken together, the results of this thesis support the use of TLR agonists to treat asthma. The most favorable efficacy/safety ratio is to be expected from TLR-based therapies combining TLR4 or TLR9 agonists with allergen in specific immunotherapy. In regard to TLR agonist monotherapy, R848 and CpG showed the most promising profiles, CpG particularly in a model of severe chronic asthma. However, since all TLR agonists used in this study also showed pro-inflammatory potential, the safety aspect of such an approach needs to be taken into account.
Fluorescently labeled human immunodeficiency virus (HIV) derivatives, combined with the use of advanced fluorescence microscopy techniques, allow the direct visualization of dynamic events and individual steps in the viral life cycle. HIV proteins tagged with fluorescent proteins (FPs) have been successfully used for live-cell imaging analyses of HIV-cell interactions. However, FPs display limitations with respect to their physicochemical properties, and their maturation kinetics. Furthermore, several independent FP-tagged constructs have to be cloned and characterized in order to obtain spectral variations suitable for multi-color imaging setups. In contrast, the so-called SNAP-tag represents a genetically encoded non-fluorescent tag which mediates specific covalent coupling to fluorescent substrate molecules in a self-labeling reaction. Fusion of the SNAP-tag to the protein of interest allows specific labeling of the fusion protein with a variety of synthetic dyes, thereby offering enhanced flexibility for fluorescence imaging approaches. Here we describe the construction and characterization of the HIV derivative HIV(SNAP), which carries the SNAP-tag as an additional domain within the viral structural polyprotein Gag. Introduction of the tag close to the C-terminus of the matrix domain of Gag did not interfere with particle assembly, release or proteolytic virus maturation. The modified virions were infectious and could be propagated in tissue culture, albeit with reduced replication capacity. Insertion of the SNAP domain within Gag allowed specific staining of the viral polyprotein in the context of virus producing cells using a SNAP reactive dye as well as the visualization of individual virions and viral budding sites by stochastic optical reconstruction microscopy. Thus, HIV(SNAP) represents a versatile tool which expands the possibilities for the analysis of HIV-cell interactions using live cell imaging and sub-diffraction fluorescence microscopy.
Epimutations in Germ-Cell and Embryo Development: Possible Consequences for Assisted Reproduction
(2011)
Assisted reproductive technologies (ART) emerged in the late 1970’s as a therapy for human infertility. Up till now more than 3 million babies have been conceived through ART, demonstrating the safety and efficiency of the technique. Published reports showed an increase in the rate of imprinting disorders (Beckwith Wiedemann Syndrome, Angelman Syndrome, etc.) in babies born after ART. What are the effects imposed through ART and should researchers reassess its safety and implications on the future offspring? Throughout this thesis, I analyzed the methylation patterns of germ cells and embryos to determine whether in vitro maturation and in vitro fertilization have a negative impact on the epigenetic patterns. Furthermore, DNA methylation was compared between sperm of infertile and presumably fertile controls in order to understand whether epigenetic disturbances lead to infertility at the first place. The occurrence of methylation aberrations in germ cells of infertile patients could be transmitted to new-borns and then cause epigenetic disorders. In order to elucidate the imprinting status within single cells, I developed a new technique based on limiting dilution where bisulfite treated DNA is distributed across several wells before amplification. This allowed methylation measurement at the single allele level as well parent of origin detection. In a total of 141 sperm samples from couples undergoing in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) including 106 with male factor or combined infertility and 28 with female infertility, I detected a significant correlation between lower quality of semen parameters (sperm count, percentage of abnormal sperm, and percentage of motile sperm) and the rate of imprinting errors. ALU repeats displayed a higher methylation in sperm DNA of patients leading to a pregnancy and live birth, compared to patients in which pregnancy was not achieved or a spontaneous abortion occurred. A discriminant analysis based on ALU methylation allowed correct classification of >70% of cases. Preliminary data from illumina methylation arrays where more than 27,000 CpGs were analyzed determined that only a single CpG site from the open reading frame C14orf93 was significantly different between the infertile and presumably fertile control group. However, further improvements on data normalization might permit detection of other differentially methylated regions. Comparison of embryos after natural conception, in vitro fertilized embryos from superovulated oocytes, and embryos achieved through fertilization of in vitro cultured oocytes revealed no dramatic effect on the imprinting patterns of Igf2r, H19, and Snrpn. Oocyte cryotop vitrification did not result in a dramatic increase of imprinting mutations in oocytes even though the rate of sporadic methylation errors in single Snrpn CpGs were higher within the in-vitrified group. Collectively, the results I will present within this thesis suggest an increase in the rate of imprinting errors within the germ cells of infertile patients, in addition to a decrease in genome wide methylation of ALU repetitive elements. I did not observe a detrimental effect on the methylation patterns of oocytes and the resulting embryos using in vitro maturation of oocytes and/or standard IVF with in vivo grown superovulated oocytes.
We review fluorescent probes that can be photoswitched or photoactivated and are suited for single-molecule localization based super-resolution microscopy. We exploit the underlying photochemical mechanisms that allow photoswitching of many synthetic organic fluorophores in the presence of reducing agents, and study the impact of these on the photoswitching properties of various photoactivatable or photoconvertible fluorescent proteins. We have identified mEos2 as a fluorescent protein that exhibits reversible photoswitching under various imaging buffer conditions and present strategies to characterize reversible photoswitching. Finally, we discuss opportunities to combine fluorescent proteins with organic fluorophores for dual-color photoswitching microscopy.
We review fluorescent probes that can be photoswitched or photoactivated and are suited for single-molecule localization based super-resolution microscopy. We exploit the underlying photochemical mechanisms that allow photoswitching of many synthetic organic fluorophores in the presence of reducing agents, and study the impact of these on the photoswitching properties of various photoactivatable or photoconvertible fluorescent proteins. We have identified mEos2 as a fluorescent protein that exhibits reversible photoswitching under various imaging buffer conditions and present strategies to characterize reversible photoswitching. Finally, we discuss opportunities to combine fluorescent proteins with organic fluorophores for dual-color photoswitching microscopy.
Mammalian Sun1 belongs to an evolutionarily conserved family of inner nuclear membrane proteins, which are known as SUN domain proteins. SUN domain proteins interact with KASH domain partners to form bridging complexes, so-called LINC complexes, that physically connect the nuclear interior to the cytoskeleton. LINC complexes are critical for nuclear integrity and play fundamental roles in nuclear positioning, shaping and movement. The mammalian genome codes for at least five different SUN domain proteins used for the formation of a number of different LINC complexes. Recently, we reported on the identification of everal Sun1 isoforms, which tremendously enlarges the alternatives to form functional LINC complexes. We now confirmed that Sun1 actually exists in at least seven distinct splice variants. Besides that, we observed that expression of individual Sun1 isoforms remarkably depends on the cell type, suggesting a cell type-specific adaption of Sun1 dependent LINC complexes to specific cellular and physiological requirements.
For a large fraction of the proteins expressed in the human brain only the primary structure is known from the genome project. Proteins conserved in evolution can be studied in genetic models such as Drosophila. In this doctoral thesis monoclonal antibodies (mAbs) from the Wuerzburg Hybridoma library are produced and characterized with the aim to identify the target antigen. The mAb ab52 was found to be an IgM which recognized a cytosolic protein of Mr ~110 kDa on Western blots. The antigen was resolved by two-dimensional gel electrophoresis (2DE) as a single distinct spot. Mass spectrometric analysis of this spot revealed EPS-15 (epidermal growth factor receptor pathway substrate clone 15) to be a strong candidate. Another mAb from the library, aa2, was already found to recognize EPS-15, and comparison of the signal of both mAbs on Western blots of 1D and 2D electrophoretic separations revealed similar patterns, hence indicating that both antigens could represent the same protein. Finally absence of the wild-type signal in homozygous Eps15 mutants in a Western blot with ab52 confirmed the ab52 antigen to be EPS-15. Thus both the mAbs aa2 and ab52 recognize the Drosophila homologue of EPS-15. The mAb aa2, being an IgG, is more suitable for applications like immunoprecipitation (IP). It has already been submitted to the Developmental Studies Hybridoma Bank (DSHB) to be easily available for the entire research community. The mAb na21 was also found to be an IgM. It recognizes a membrane associated antigen of Mr ~10 kDa on Western blots. Due to the membrane associated nature of the protein, it was not possible to resolve it by 2DE and due to the IgM nature of the mAb it was not possible to enrich the antigen by IP. Preliminary attempts to biochemically purify the endogenously expressed protein from the tissue, gave promising results but could not be completed due to lack of time. Thus biochemical purification of the protein seems possible in order to facilitate its identification by mass spectrometry. Several other mAbs were studied for their staining pattern on cryosections and whole mounts of Drosophila brains. However, many of these mAbs stained very few structures in the brain, which indicated that only a very limited amount of protein would be available as starting material. Because these antibodies did not produce signals on Western blots, which made it impossible to enrich the antigens by electrophoretic methods, we did not attempt their purification. However, the specific localization of these proteins makes them highly interesting and calls for their further characterization, as they may play a highly specialized role in the development and/or function of the neural circuits they are present in. The purification and identification of such low expression proteins would need novel methods of enrichment of the stained structures.
This work delves into the recently developed ‘Whedo’-aquaculture-system in the rural community of Malanville (North Benin)and aims on providing a closer insight on this – for the area--recent system including the ecological but also the sociological and economical aspects in order to develop this extensive traditional fishery to a more productive semi-intensive aquaculture system. With the retreat of the flood ‘Whedos’ usually become infested with numerous hydato-and tenagophytes, while the presence and density of the free-floating macrophytes were positively related to the nutrient content of the ‘Whedo’. Extensive plant infestation also affects water quality through the decomposition of organic material and its accumulation in thick mud layers on the pond bottom as well as through the nocturnal oxygen consumption. Unfavourable water quality, especially low dissolved oxygen as well as high conductivity and nitrite levels, was identified to be the main factor determining which fish species were able to survive the harsh conditions prevailing in the ‘Whedos’ during the dry season. With the deteriorating water quality with advancing dry season, fish diversity decreased significantly leaving only species that are highly adapted to such unfavourable conditions. The most abundant species were Clarias gariepinus, Heterotis niloticus, Oreochromis niloticus L., Hemichromis c.f. letourneauxi, Polypterus senegalus and Epiplatys spilargyreius. Besides, the investigations also concentrated on the fish diversity of the rivers Niger and Sota with the results that for three species distribution gaps could be closed and for further three species their already known distribution could be expanded. But otherwise it could also be detected that some economically important species that were abundant in the past. In regard to the ‘Whedo’-management, the investigations showed that the owners lack most of the knowledge on appropriate management strategies, e.g. the feeding and stocking regime. The exploitation period depends on the extent of the previous annual flood and the location of the ‘Whedo’ within the floodplain, but the main season is from February to April. The biomass harvested on a hectare basis separated for each of the ‘Whedos’ averaged 17 tons/ha in 2008 and 8.6 tons/ha in 2009. However, 72 percent of the total biomass of Clarias only had an average weight of 40 grams. Therefore, two separated feeding trials were conducted and in total 6 supplementary feeds were tested on Clarias gariepinus. Groundnut cake, fish trash, rice bran, blood meal and azolla meal were used in different combination and rations to formulate the experimental diets. Diet containing 19 percent blood meal resulted in the best economical benefits showing that the use of high quality feed ingredients such as groundnut cake is not recommendable because local fish prices are too low to compensate the additional feeding costs. Instead of high quality feed farmers should focus on ingredients that are free of charge and easy to process. The supplementation based on 19 percent blood meal resulted in the doubling of the net profit compared to the income based on feeding only rice bran, thus provided higher additional income, enhancing the livelihood of the fish farmers. Concluding, the ‘Whedo’-aquaculture system is still in its infancy but nevertheless is an attractive system for the rural population because of existing knowledge of post-flood wetland fisheries as well as the low investment needed for its installation. Additionally, the local fish supply will increase and hence not only contribute to a better provision of protein-rich food and reduced pressure on the wild fish stocks but might also prevent fish prices to increase in a way that the poor won’t be able anymore to afford their most important source of animal protein. But fish farmers need more knowledge on appropriate management strategies and thus should be provided with technical support to guarantee a successful development and not to discourage the owners as a consequence of avoidable failures. Furthermore, the use of supplementary feed offers a cheap and effective means to increase the biomass production and thus enhance the extensive fishery to a semi-intensive aquaculture system.
Non-target effects of a multiple insect resistant Bt-maize on the honey bee (Apis mellifera L.)
(2011)
Honey bee pollination is an ecologically and economically important ecosystem service. New methodological developments are needed to research the underlying factors of globally observed bee losses. The honey bee (Apis mellifera) is a key non-target arthropod species for environmental risk assessment of genetically modified (GM) crops. For GM-crop risk assessments, mainly methods for monitoring adult honey bees under laboratory conditions are documented. However, protocols with robust methods for standardized colonies or in vitro reared honey bee larvae are currently lacking. Within the research, presented in this this dissertation, multiple methodological developments are achieved; a mortality trap (Chapter II), a ‘full life cycle test’ (III), a novel in vitro rearing methodology (IV), a standardized in vitro test for Bt-pollen (V), a mixed toxicity test for purified transgenic proteins (VI), and a bacterial flora test with pollen digestion rate monitoring (VII). Overall, the studies did not indicate a detrimental effect caused by Bt-maize pollen, or by purified Bt-proteins at worst case exposure levels. Considering the risk for honey bees and larvae, we conclude that the tested Bt-maize Mon89034xMon88017 is not likely to cause harm to honey bee colonies. The study methods presented are highly recommended for future environmental risk assessment studies testing GM-crop biosafety on honey bees.