Refine
Has Fulltext
- yes (65)
Is part of the Bibliography
- yes (65)
Year of publication
- 2017 (65) (remove)
Document Type
- Journal article (65) (remove)
Language
- English (65)
Keywords
- biology (8)
- Trypanosoma (4)
- ants (4)
- social systems (4)
- Apis mellifera (3)
- Drosophila melanogaster (3)
- animal sociality (3)
- fungi (3)
- Biology (2)
- DNA methylation (2)
- Drosophila (2)
- carbon dioxide (2)
- cell differentiation (2)
- ceramide (2)
- chemotherapy (2)
- comparative genomics (2)
- cytokines (2)
- foraging (2)
- genetic variation (2)
- humidity (2)
- learning (2)
- memory (2)
- methylation (2)
- mushroom bodies (2)
- nesting habits (2)
- symbiosis (2)
- toxins (2)
- 5-fluorouracil (1)
- Acyrthosiphon pisum (1)
- Aspergillus fumigatus (1)
- B cell receptors (1)
- B cells (1)
- BMP (1)
- Burkina Faso (1)
- Caenorhabditis elegans (1)
- Cell surface proteomics (1)
- Chlamydia trachomatis (1)
- Circadian rhythms and sleep (1)
- CoA (1)
- Computer software (1)
- DNA damage (1)
- Dunce isoforms (1)
- EZH2 (1)
- Enzyme Regulation (1)
- Enzyme kinetics (1)
- Enzyme metabolism (1)
- Enzyme regulation (1)
- Enzymes (1)
- Epicardium-derived cells (1)
- Genetics (1)
- HECT Ligase (1)
- HUWE1 (1)
- Human atrial stromal cells (1)
- Kryptolebias marmoratus (1)
- Latrophilin (1)
- MITE (1)
- Mcl-1 (1)
- Medicine (1)
- Megalobrama amblycephala (1)
- Megaponera analis (1)
- Meliponini (1)
- Metabolic pathways (1)
- Molecular Biophysics (1)
- N-terminal domain (1)
- NAD (1)
- NFATc1 (1)
- Neisseria (1)
- Neisseria meningitidis (1)
- Neuromuscular junctions (1)
- OGEE v2 (1)
- P14ARF (1)
- PDE4d (1)
- PER (1)
- Predictive toxicology (1)
- RNA in situ hybridization (1)
- RNA interference (1)
- Saccharomyces cerevisiae (1)
- Septins (1)
- Staphylococcus aureus (1)
- Structural Biology (1)
- Synapses (1)
- Synaptic vesicles (1)
- T cells (1)
- T-cadherin (1)
- TP53 (1)
- Toxicity (1)
- Transcriptional control (1)
- Trypanosoma brucei (1)
- Ubiquitin (1)
- Vesicles (1)
- Wilms tumour (1)
- X-Ray Chrystallography (1)
- Zebrafish (1)
- acute myeloid leukaemia (1)
- adhesion GPCR (1)
- agroecology (1)
- alcohol tolerance (1)
- alu elements (1)
- anaplasia (1)
- antimicrobials (1)
- bees (1)
- behavior (1)
- behavioural ecology (1)
- biogenic amines (1)
- bioinformatics (1)
- biomarker (1)
- biomaterials (1)
- biophysics (1)
- blood (1)
- blood platelets (1)
- bone (1)
- brain (1)
- brain development (1)
- breast cancer (1)
- cadherin-13 (CDH13) (1)
- cancer treatment (1)
- cash crops (1)
- catabolism (1)
- cell binding (1)
- cell cycle (1)
- cell cycle and cell division (1)
- cell proliferation (1)
- cell-autonomous defense (1)
- cellular function (1)
- cellular stress (1)
- central clocks (1)
- central complex (1)
- ceramide analogs (1)
- cholera (1)
- chronobiology (1)
- circadian clock (1)
- circadian mechanisms (1)
- clinical genetics (1)
- cloning (1)
- cognition (1)
- colorectal carcinoma (1)
- compound conditioning (1)
- confocal laser scanning microscopy (1)
- confocal-microscopy based automated quantification (1)
- cotton (1)
- crotonase (1)
- cryptic (1)
- cytokinesis (1)
- cytotoxic T cells (1)
- dCIRL (1)
- damped circadian clock (1)
- decision-making (1)
- deformed wing virus (1)
- dehydrogenase (1)
- desert ants (1)
- deubiquitinase (1)
- differential olfactory conditioning (1)
- division of labor (1)
- dorsal raphe (1)
- dunce (1)
- eEF1A1 (1)
- eclosion (1)
- ecological genetics (1)
- ecosystem services (1)
- epigenetics (1)
- eukaryota (1)
- evolutionary genetics (1)
- evolutionary response (1)
- fetal cord blood (1)
- fetal programming (1)
- fibroblasts (1)
- floral resource distribution (1)
- fluorescence imaging (1)
- forager (1)
- foraging behaviour (1)
- functional complementarity (1)
- functional redundancy (1)
- fungal infection (1)
- fungal physiology (1)
- fungal structure (1)
- gambiense (1)
- gene essentiality database (1)
- gene expression (1)
- gene regulation (1)
- genetic loci (1)
- genome collection (1)
- genome integrity (1)
- genome sequencing (1)
- genomic libraries (1)
- genomic sequence (1)
- genomics research (1)
- gestational diabetes mellitus (1)
- glioblastoma multiforme (1)
- glycoprotein Ib (1)
- gut microflora (1)
- habitat information (1)
- hangover (1)
- herbivorous diet (1)
- herpes virus (1)
- high-throughput screening (1)
- histones (1)
- honey bees (1)
- honeybees (1)
- human cancer cell lines (1)
- hyperexpression techniques (1)
- ichthyology (1)
- image analysis (1)
- imaging the immune system (1)
- immune cells (1)
- immune evasion (1)
- infectious diseases (1)
- infectious-disease diagnostics (1)
- infrared radiation (1)
- insect (1)
- insulin treatment (1)
- intermuscular bone (1)
- kinesin (1)
- landscape ecology (1)
- leaves (1)
- light pulses (1)
- lipids (1)
- look-back behavior (1)
- lung cancer (1)
- lymphocyte activation (1)
- macrophages (1)
- mass spectrometry (1)
- mating success (1)
- mechanobiology (1)
- mechanotransduction (1)
- megakaryocytes (1)
- membrane receptor signaling (1)
- messenger RNA (1)
- metabolism (1)
- metabotropic signalling (1)
- metagenomics (1)
- microRNAs (1)
- microRNA–target interaction (1)
- microbiome (1)
- microswimmer (1)
- migration (1)
- mitochondria (1)
- molecular neuroscience (1)
- molting (1)
- morphometry (1)
- multiple myeloma (1)
- mushroom body (1)
- natural killer cells (1)
- neisseria meningitidis (1)
- nephroblastoma (1)
- nesting habit (1)
- networks (1)
- neuroanatomy (1)
- neurodevelopment (1)
- neuronal development (1)
- neuropeptide pathway (1)
- none (1)
- nurse bee (1)
- nutrition (1)
- nutritional ecology (1)
- octopamine (1)
- optogenetics (1)
- orientation (1)
- osteocytes (1)
- oxaliplatin (1)
- parasitic cell cycles (1)
- parasitic diseases (1)
- pattern recognition receptors (1)
- perception (1)
- peripheral clocks (1)
- plant-insect interactions (1)
- plant–insect interactions (1)
- pollen (1)
- pollination (1)
- pollinator decline (1)
- population structure (1)
- prefrontal cortex (1)
- proGenomes (1)
- proboscis extension reflex (1)
- prokaryotic clade (1)
- prokaryotic subspecies (1)
- protein structure (1)
- proteins (1)
- proteomes (1)
- psychiatric disorders (1)
- quality control (1)
- radial glia (1)
- reactivating p53 and inducing tumor apoptosis (RITA) (1)
- recruitment (1)
- regulation (1)
- regulatory T cells (1)
- regulatory circuit downstream (1)
- relA (1)
- replication (1)
- reproductive asynchrony (1)
- rescue behavior (1)
- resin (1)
- retinal development (1)
- sacbrood virus (1)
- season (1)
- sensory physiology (1)
- sept3 (1)
- sept5a (1)
- sept5b (1)
- septin (1)
- sequence assembly tools (1)
- serotonin (1)
- sesame (1)
- sex-specific mortality (1)
- sexual dimorphism in timing (1)
- signal transduction (1)
- signaling (1)
- sky-compass pathway (1)
- sleeping sickness (1)
- small interfering RNAs (1)
- social immunity (1)
- sphingomyelinase (1)
- spider (1)
- spidroin (1)
- string database (1)
- stringent response (1)
- structural biology (1)
- substrate channeling (1)
- super-resolution microscopy (1)
- systems biology (1)
- taxonomic description (1)
- tetracyclines (1)
- therapeutic strategy (1)
- throat (1)
- transcriptome (1)
- treatment (1)
- tsetse fly (1)
- tumour heterogeneity (1)
- vector navigation (1)
- video recording (1)
- virulenceregulatory evolution (1)
- visual orientation (1)
- whole genome (1)
- yellow fluorescent protein (1)
Institute
- Theodor-Boveri-Institut für Biowissenschaften (65) (remove)
Blood platelets are produced by large bone marrow (BM) precursor cells, megakaryocytes (MKs), which extend cytoplasmic protrusions (proplatelets) into BM sinusoids. The molecular cues that control MK polarization towards sinusoids and limit transendothelial crossing to proplatelets remain unknown. Here, we show that the small GTPases Cdc42 and RhoA act as a regulatory circuit downstream of the MK-specific mechanoreceptor GPIb to coordinate polarized transendothelial platelet biogenesis. Functional deficiency of either GPIb or Cdc42 impairs transendothelial proplatelet formation. In the absence of RhoA, increased Cdc42 activity and MK hyperpolarization triggers GPIb-dependent transmigration of entire MKs into BM sinusoids. These findings position Cdc42 (go-signal) and RhoA (stop-signal) at the centre of a molecular checkpoint downstream of GPIb that controls transendothelial platelet biogenesis. Our results may open new avenues for the treatment of platelet production disorders and help to explain the thrombocytopenia in patients with Bernard–Soulier syndrome, a bleeding disorder caused by defects in GPIb-IX-V.
The human ubiquitin ligase HUWE1 has key roles in tumorigenesis, yet it is unkown how its activity is regulated. We present the crystal structure of a C-terminal part of HUWE1, including the catalytic domain, and reveal an asymmetric auto-inhibited dimer. We show that HUWE1 dimerizes in solution and self-associates in cells, and that both occurs through the crystallographic dimer interface. We demonstrate that HUWE1 is inhibited in cells and that it can be activated by disruption of the dimer interface. We identify a conserved segment in HUWE1 that counteracts dimer formation by associating with the dimerization region intramolecularly. Our studies reveal, intriguingly, that the tumor suppressor p14ARF binds to this segment and may thus shift the conformational equilibrium of HUWE1 toward the inactive state. We propose a model, in which the activity of HUWE1 underlies conformational control in response to physiological cues—a mechanism that may be exploited for cancer therapy.
Timing seasonal events, like reproduction or diapause, is crucial for the survival of many species. Global change causes phenologies worldwide to shift, which requires a mechanistic explanation of seasonal time measurement. Day length (photoperiod) is a reliable indicator of winter arrival, but it remains unclear how exactly species measure day length. A reference for time of day could be provided by a circadian clock, by an hourglass clock, or, as some newer models suggest, by a damped circadian clock. However, damping of clock outputs has so far been rarely observed. To study putative clock outputs of Acyrthosiphon pisum aphids, we raised individual nymphs on coloured artificial diet, and measured rhythms in metabolic activity in light-dark illumination cycles of 16:08 hours (LD) and constant conditions (DD). In addition, we kept individuals in a novel monitoring setup and measured locomotor activity. We found that A. pisum is day-active in LD, potentially with a bimodal distribution. In constant darkness rhythmicity of locomotor behaviour persisted in some individuals, but patterns were mostly complex with several predominant periods. Metabolic activity, on the other hand, damped quickly. A damped circadian clock, potentially driven by multiple oscillator populations, is the most likely explanation of our results.
For persistent infections of the mammalian host, African trypanosomes limit their population size by quorum sensing of the parasite-excreted stumpy induction factor (SIF), which induces development to the tsetse-infective stumpy stage. We found that besides this cell density-dependent mechanism, there exists a second path to the stumpy stage that is linked to antigenic variation, the main instrument of parasite virulence. The expression of a second variant surface glycoprotein (VSG) leads to transcriptional attenuation of the VSG expression site (ES) and immediate development to tsetse fly infective stumpy parasites. This path is independent of SIF and solely controlled by the transcriptional status of the ES. In pleomorphic trypanosomes varying degrees of ES-attenuation result in phenotypic plasticity. While full ES-attenuation causes irreversible stumpy development, milder attenuation may open a time window for rescuing an unsuccessful antigenic switch, a scenario that so far has not been considered as important for parasite survival.
Intracellular pathogenic microorganisms and toxins exploit host cell mechanisms to enter, exert their deleterious effects as well as hijack host nutrition for their development. A potential approach to treat multiple pathogen infections and that should not induce drug resistance is the use of small molecules that target host components. We identifed the compound 1-adamantyl (5-bromo-2-methoxybenzyl) amine (ABMA) from a cell-based high throughput screening for its capacity to protect human cells and mice against ricin toxin without toxicity. This compound efciently protects cells against various toxins and pathogens including viruses, intracellular bacteria and parasite. ABMA provokes Rab7-positive late endosomal compartment accumulation in mammalian cells without affecting other organelles (early endosomes, lysosomes, the Golgi apparatus, the endoplasmic reticulum or the nucleus). As the mechanism of action of ABMA is restricted to host-endosomal compartments, it reduces cell infection by pathogens that depend on this pathway to invade cells. ABMA may represent a novel class of broad-spectrum compounds with therapeutic potential against diverse severe infectious diseases.
Theory predicts that males and females should often join the mating pool at different times (sexual dimorphism in timing of emergence [SDT]) as the degree of SDT affects female mating success. We utilize an analytical model to explore (1) how important SDT is for female mating success, (2) how mating success might change if either sex's mortality (abruptly) increases, and (3) to what degree evolutionary responses in SDT may be able to mitigate the consequences of such mortality increase. Increasing male pre‐mating mortality has a non‐linear effect on the fraction of females mated: The effect is initially weak, but at some critical level a further increase in male mortality has a stronger effect than a similar increase in female mortality. Such a change is expected to impose selection for reduced SDT. Increasing mortality during the mating season has always a stronger effect on female mating success if the mortality affects the sex that emerges first. This bias results from the fact that enhancing mortality of the earlier emerging sex reduces female–male encounter rates. However, an evolutionary response in SDT may effectively mitigate such consequences. Further, if considered independently for females and males, the predicted evolutionary response in SDT could be quite dissimilar. The difference between female and male evolutionary response in SDT leads to marked differences in the fraction of fertilized females under certain conditions. Our model may provide general guidelines for improving harvesting of populations, conservation management of rare species under altered environmental conditions, or maintaining long‐term efficiency of pest‐control measures.
Epigenetic alterations may contribute to the generation of cancer cells in a multi-step process of tumorigenesis following irradiation of normal body cells. Primary human fibroblasts with intact cell cycle checkpoints were used as a model to test whether X-ray irradiation with 2 and 4 Gray induces direct epigenetic effects (within the first cell cycle) in the exposed cells. ELISA-based fluorometric assays were consistent with slightly reduced global DNA methylation and hydroxymethylation, however the observed between-group differences were usually not significant. Similarly, bisulfite pyrosequencing of interspersed LINE-1 repeats and centromeric α-satellite DNA did not detect significant methylation differences between irradiated and non-irradiated cultures. Methylation of interspersed ALU repeats appeared to be slightly increased (one percentage point; p = 0.01) at 6 h after irradiation with 4 Gy. Single-cell analysis showed comparable variations in repeat methylation among individual cells in both irradiated and control cultures. Radiation-induced changes in global repeat methylation, if any, were much smaller than methylation variation between different fibroblast strains. Interestingly, α-satellite DNA methylation positively correlated with gestational age. Finally, 450K methylation arrays mainly targeting genes and CpG islands were used for global DNA methylation analysis. There were no detectable methylation differences in genic (promoter, 5' UTR, first exon, gene body, 3' UTR) and intergenic regions between irradiated and control fibroblast cultures. Although we cannot exclude minor effects, i.e. on individual CpG sites, collectively our data suggest that global DNA methylation remains rather stable in irradiated normal body cells in the early phase of DNA damage response.
Certain fatty acids and sphingoid bases found at mucosal surfaces are known to have antibacterial activity and are thought to play a more direct role in innate immunity against bacterial infections. Herein, we analysed the antibacterial activity of sphingolipids, including the sphingoid base sphingosine as well as short-chain C\(_{6}\) and long-chain C\(_{16}\)-ceramides and azido-functionalized ceramide analogs against pathogenic Neisseriae. Determination of the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) demonstrated that short-chain ceramides and a ω-azido-functionalized C\(_{6}\)-ceramide were active against Neisseria meningitidis and N. gonorrhoeae, whereas they were inactive against Escherichia coli and Staphylococcus aureus. Kinetic assays showed that killing of N. meningitidis occurred within 2 h with ω–azido-C\(_{6}\)-ceramide at 1 X the MIC. Of note, at a bactericidal concentration, ω–azido-C\(_{6}\)-ceramide had no significant toxic effect on host cells. Moreover, lipid uptake and localization was studied by flow cytometry and confocal laser scanning microscopy (CLSM) and revealed a rapid uptake by bacteria within 5 min. CLSM and super-resolution fluorescence imaging by direct stochastic optical reconstruction microscopy demonstrated homogeneous distribution of ceramide analogs in the bacterial membrane. Taken together, these data demonstrate the potent bactericidal activity of sphingosine and synthetic short-chain ceramide analogs against pathogenic Neisseriae.
Plants initially accepted by foraging leaf-cutting ants are later avoided if they prove unsuitable for their symbiotic fungus. Plant avoidance is mediated by the waste produced in the fungus garden soon after the incorporation of the unsuitable leaves, as foragers can learn plant odors and cues from the damaged fungus that are both present in the recently produced waste particles. We asked whether avoidance learning of plants unsuitable for the symbiotic fungus can take place entirely at the colony dump. In order to investigate whether cues available in the waste chamber induce plant avoidance in naïve subcolonies, we exchanged the waste produced by subcolonies fed either fungicide-treated privet leaves or untreated leaves and measured the acceptance of untreated privet leaves before and after the exchange of waste. Second, we evaluated whether foragers could perceive the avoidance cues directly at the dump by quantifying the visits of labeled foragers to the waste chamber. Finally, we asked whether foragers learn to specifically avoid untreated leaves of a plant after a confinement over 3 hours in the dump of subcolonies that were previously fed fungicide-treated leaves of that species. After the exchange of the waste chambers, workers from subcolonies that had access to waste from fungicide-treated privet leaves learned to avoid that plant. One-third of the labeled foragers visited the dump. Furthermore, naïve foragers learned to avoid a specific, previously unsuitable plant if exposed solely to cues of the dump during confinement. We suggest that cues at the dump enable foragers to predict the unsuitable effects of plants even if they had never been experienced in the fungus garden.
Bee pollination increases yield quantity and quality of cash crops in Burkina Faso, West Africa
(2017)
Mutualistic biotic interactions as among flowering plants and their animal pollinators are a key component of biodiversity. Pollination, especially by insects, is a key element in ecosystem functioning, and hence constitutes an ecosystem service of global importance. Not only sexual reproduction of plants is ensured, but also yields are stabilized and genetic variability of crops is maintained, counteracting inbreeding depression and facilitating system resilience. While experiencing rapid environmental change, there is an increased demand for food and income security, especially in sub-Saharan communities, which are highly dependent on small scale agriculture. By combining exclusion experiments, pollinator surveys and field manipulations, this study for the first time quantifies the contribution of bee pollinators to smallholders’ production of the major cash crops, cotton and sesame, in Burkina Faso. Pollination by honeybees and wild bees significantly increased yield quantity and quality on average up to 62%, while exclusion of pollinators caused an average yield gap of 37% in cotton and 59% in sesame. Self-pollination revealed inbreeding depression effects on fruit set and low germination rates in the F1-generation. Our results highlight potential negative consequences of any pollinator decline, provoking risks to agriculture and compromising crop yields in sub-Saharan West Africa.