TY - JOUR A1 - Reichardt, Joerg A1 - Alamino, Roberto A1 - Saad, David T1 - The interplay between microscopic and mesoscopic structures in complex networks N2 - Understanding a complex network’s structure holds the key to understanding its function. The physics community has contributed a multitude of methods and analyses to this cross-disciplinary endeavor. Structural features exist on both the microscopic level, resulting from differences between single node properties, and the mesoscopic level resulting from properties shared by groups of nodes. Disentangling the determinants of network structure on these different scales has remained a major, and so far unsolved, challenge. Here we show how multiscale generative probabilistic exponential random graph models combined with efficient, distributive message-passing inference techniques can be used to achieve this separation of scales, leading to improved detection accuracy of latent classes as demonstrated on benchmark problems. It sheds new light on the statistical significance of motif-distributions in neural networks and improves the link-prediction accuracy as exemplified for gene-disease associations in the highly consequential Online Mendelian Inheritance in Man database. KW - Netzwerk KW - Mesoskopisches System Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-68993 ER - TY - JOUR A1 - Rauert, H. A1 - Stühmer, T. A1 - Bargou, R. A1 - Wajant, H. A1 - Siegmund, D. T1 - TNFR1 and TNFR2 regulate the extrinsic apoptotic pathway in myeloma cells by multiple mechanisms N2 - The huge majority of myeloma cell lines express TNFR2 while a substantial subset of them failed to show TNFR1 expression. Stimulation of TNFR1 in the TNFR1-expressing subset of MM cell lines had no or only a very mild effect on cellular viability. Surprisingly, however, TNF stimulation enhanced cell death induction by CD95L and attenuated the apoptotic effect of TRAIL. The contrasting regulation of TRAIL- and CD95L-induced cell death by TNF could be traced back to the concomitant NFjBmediated upregulation of CD95 and the antiapoptotic FLIP protein. It appeared that CD95 induction, due to its strength, overcompensated a rather moderate upregulation of FLIP so that the net effect of TNF-induced NFjB activation in the context of CD95 signaling is pro-apoptotic. TRAIL-induced cell death, however, was antagonized in response to TNF because in this context only the induction of FLIP is relevant. Stimulation of TNFR2 in myeloma cells leads to TRAF2 depletion. In line with this, we observed cell death induction in TNFR1-TNFR2-costimulated JJN3 cells. Our studies revealed that the TNF-TNF receptor system adjusts the responsiveness of the extrinsic apoptotic pathway in myeloma cells by multiple mechanisms that generate a highly context-dependent net effect on myeloma cell survival. KW - Medizin KW - apoptosis KW - CD95 KW - multiple myeloma KW - NFkB KW - TNF KW - TRAIL Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-76092 ER - TY - JOUR A1 - Rauert, H. A1 - Stühmer, T. A1 - Bargou, R. A1 - Wajant, H. A1 - Siegmund, D. T1 - TNFR1 and TNFR2 regulate the extrinsic apoptotic pathway in myeloma cells by multiple mechanisms JF - Cell Death and Disease N2 - The huge majority of myeloma cell lines express TNFR2 while a substantial subset of them failed to show TNFR1 expression. Stimulation of TNFR1 in the TNFR1-expressing subset of MM cell lines had no or only a very mild effect on cellular viability. Surprisingly, however, TNF stimulation enhanced cell death induction by CD95L and attenuated the apoptotic effect of TRAIL. The contrasting regulation of TRAIL- and CD95L-induced cell death by TNF could be traced back to the concomitant NFjBmediated upregulation of CD95 and the antiapoptotic FLIP protein. It appeared that CD95 induction, due to its strength, overcompensated a rather moderate upregulation of FLIP so that the net effect of TNF-induced NFjB activation in the context of CD95 signaling is pro-apoptotic. TRAIL-induced cell death, however, was antagonized in response to TNF because in this context only the induction of FLIP is relevant. Stimulation of TNFR2 in myeloma cells leads to TRAF2 depletion. In line with this, we observed cell death induction in TNFR1-TNFR2-costimulated JJN3 cells. Our studies revealed that the TNF-TNF receptor system adjusts the responsiveness of the extrinsic apoptotic pathway in myeloma cells by multiple mechanisms that generate a highly context-dependent net effect on myeloma cell survival KW - apoptosis KW - CD95 KW - multiple myeloma KW - NFkB KW - TNF KW - TRAIL KW - NF-Kappa-B KW - Tumor-necrosis-factor KW - Factor receptor KW - Factor-alpha KW - Activation KW - Polymorphisms KW - Inhibitor KW - Promoter KW - Transcription KW - Expression Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-133486 VL - 2 ER - TY - JOUR A1 - Rantamäki, Tomi A1 - Vesa, Liisa A1 - Antila, Hanna A1 - Di Lieto, Antonio A1 - Tammela, Päivi A1 - Schmitt, Angelika A1 - Lesch, Klaus-Peter A1 - Rios, Maribel A1 - Castrén, Eero T1 - Antidepressant Drugs Transactivate TrkB Neurotrophin Receptors in the Adult Rodent Brain Independently of BDNF and Monoamine Transporter Blockade JF - PLoS ONE N2 - Background: Antidepressant drugs (ADs) have been shown to activate BDNF (brain-derived neurotrophic factor) receptor TrkB in the rodent brain but the mechanism underlying this phenomenon remains unclear. ADs act as monoamine reuptake inhibitors and after prolonged treatments regulate brain bdnf mRNA levels indicating that monoamine-BDNF signaling regulate AD-induced TrkB activation in vivo. However, recent findings demonstrate that Trk receptors can be transactivated independently of their neurotrophin ligands. Methodology: In this study we examined the role of BDNF, TrkB kinase activity and monoamine reuptake in the AD-induced TrkB activation in vivo and in vitro by employing several transgenic mouse models, cultured neurons and TrkB-expressing cell lines. Principal Findings: Using a chemical-genetic TrkB(F616A) mutant and TrkB overexpressing mice, we demonstrate that ADs specifically activate both the maturely and immaturely glycosylated forms of TrkB receptors in the brain in a TrkB kinase dependent manner. However, the tricyclic AD imipramine readily induced the phosphorylation of TrkB receptors in conditional bdnf(-/-) knock-out mice (132.4+/-8.5% of control; P = 0.01), indicating that BDNF is not required for the TrkB activation. Moreover, using serotonin transporter (SERT) deficient mice and chemical lesions of monoaminergic neurons we show that neither a functional SERT nor monoamines are required for the TrkB phosphorylation response induced by the serotonin selective reuptake inhibitors fluoxetine or citalopram, or norepinephrine selective reuptake inhibitor reboxetine. However, neither ADs nor monoamine transmitters activated TrkB in cultured neurons or cell lines expressing TrkB receptors, arguing that ADs do not directly bind to TrkB. Conclusions: The present findings suggest that ADs transactivate brain TrkB receptors independently of BDNF and monoamine reuptake blockade and emphasize the need of an intact tissue context for the ability of ADs to induce TrkB activity in brain. KW - Serotonin transporter KW - Neuronal plasticity KW - Mood disorders KW - Messenger-RNA KW - Mouse-brain KW - Rat-brain KW - Activation KW - Depression KW - Mice KW - Insensitivity Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-133746 VL - 6 IS - 6 ER - TY - JOUR A1 - Quarta, Serena A1 - Vogl, Christian A1 - Constantin, Cristina E. A1 - Üçeyler, Nurcan A1 - Sommer, Claudia A1 - Kress, Michaela T1 - Genetic evidence for an essential role of neuronally expressed IL-6 signal transducer gp130 in the induction and maintenance of experimentally induced mechanical hypersensitivity \(in\) \(vivo\) and \(in\) \(vitro\) JF - Molecular Pain N2 - Tenderness and mechanical allodynia are key symptoms of malignant tumor, inflammation and neuropathy. The proinflammatory cytokine interleukin-6 (IL-6) is causally involved in all three pathologies. IL-6 not only regulates innate immunity and inflammation but also causes nociceptor sensitization and hyperalgesia. In general and in most cell types including immune cells and sensory neurons, IL-6 binds soluble mu receptor subunits which heteromerizes with membrane bound IL-6 signal transducer gp130. In the present study, we used a conditional knock-out strategy to investigate the importance of signal transducer gp130 expressed in C nociceptors for the generation and maintenance of mechanical hypersensitivity. Nociceptors were sensitized to mechanical stimuli by experimental tumor and this nociceptor sensitization was preserved at later stages of the pathology in control mice. However, in mice with a conditional deletion of gp130 in Nav1.8 expressing nociceptors mechanical hypersensitivity by experimental tumor, nerve injury or inflammation recovery was not preserved in the maintenance phase and nociceptors exhibited normal mechanical thresholds comparable to untreated mice. Together, the results argue for IL-6 signal transducer gp130 as an essential prerequisite in nociceptors for long-term mechanical hypersensitivity associated with cancer, inflammation and nerve injury. KW - Leukemia Inhibitory Factor KW - Mediated Inflammatory Hyperalgesia KW - Necrosis-factor-Alpha KW - Oncostatin-M-Receptor KW - Rat Sensory Neurons KW - Rheumatoid-Arthritis KW - Interleukin-6-Deficient mice KW - Peripheral Inflammation KW - Thermal Hyperalgesia KW - Heat Hyperalgesia KW - proinflammatory cytokine KW - Interleukin-6 KW - chronic pain KW - nociceptor sensitization KW - hyperalgesia KW - allodynia Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-140380 VL - 7,73 ER - TY - JOUR A1 - Puschmann, Anne-Katrin A1 - Sommer, Claudia T1 - Hypervigilance or avoidance of trigger related cues in migraineurs? - A case-control study using the emotional stroop task N2 - Background: “Negative affect” is one of the major migraine triggers. The aim of the study was to assess attentional biases for negative affective stimuli that might be related to migraine triggers in migraine patients with either few or frequent migraine and healthy controls. Methods: Thirty-three subjects with frequent migraine (FM) or with less frequent episodic migraine, and 20 healthy controls conducted two emotional Stroop tasks in the interictal period. In task 1, general affective words and in task 2, pictures of affective faces (angry, neutral, happy) were used. For each task we calculated two emotional Stroop indices. Groups were compared using one-way ANOVAs. Results: The expected attentional bias in migraine patients was not found. However, in task 2 the controls showed a significant attentional bias to negative faces, whereas the FM group showed indices near zero. Thus, the FM group responded faster to negative than to positive stimuli. The difference between the groups was statistically significant. Conclusions: The findings in the FM group may reflect a learned avoidance mechanism away from affective migraine triggers. KW - Migräne Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-69103 ER - TY - JOUR A1 - Puschmann, Anne-Katrin A1 - Sommer, Claudia T1 - Hypervigilance or avoidance of trigger related cues in migraineurs? - A case-control study using the emotional stroop task JF - BMC Neurology N2 - Background "Negative affect" is one of the major migraine triggers. The aim of the study was to assess attentional biases for negative affective stimuli that might be related to migraine triggers in migraine patients with either few or frequent migraine and healthy controls. Methods Thirty-three subjects with frequent migraine (FM) or with less frequent episodic migraine, and 20 healthy controls conducted two emotional Stroop tasks in the interictal period. In task 1, general affective words and in task 2, pictures of affective faces (angry, neutral, happy) were used. For each task we calculated two emotional Stroop indices. Groups were compared using one-way ANOVAs. Results The expected attentional bias in migraine patients was not found. However, in task 2 the controls showed a significant attentional bias to negative faces, whereas the FM group showed indices near zero. Thus, the FM group responded faster to negative than to positive stimuli. The difference between the groups was statistically significant. Conclusions The findings in the FM group may reflect a learned avoidance mechanism away from affective migraine triggers. KW - migraineur KW - cue Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-137750 VL - 11 IS - 141 ER - TY - JOUR A1 - Pimentel-Elardo, Sheila M. A1 - Buback, Verena A1 - Gulder, Tobias A. M. A1 - Bugni, Tim S. A1 - Reppart, Jason A1 - Bringmann, Gerhard A1 - Ireland, Chris M. A1 - Schirmeister, Tanja A1 - Hentschel, Ute T1 - New Tetromycin Derivatives with Anti-Trypanosomal and Protease Inhibitory Activities JF - Marine drugs N2 - Four new tetromycin derivatives, tetromycins 1-4 and a previously known one, tetromycin B (5) were isolated from Streptomyces axinellae Pol001(T) cultivated from the Mediterranean sponge Axinella polypoides. Structures were assigned using extensive 1D and 2D NMR spectroscopy as well as HRESIMS analysis. The compounds were tested for antiparasitic activities against Leishmania major and Trypanosoma brucei, and for protease inhibition against several cysteine proteases such as falcipain, rhodesain, cathepsin L, cathepsin B, and viral proteases SARS-CoV M(pro), and PL(pro). The compounds showed antiparasitic activities against T. brucei and time-dependent inhibition of cathepsin L-like proteases with K(i) values in the low micromolar range. KW - cysteine protease KW - drugs KW - streptomyces KW - discovery KW - anti-trypanosomal KW - protease inhibition KW - Streptomyces axinellae KW - marine sponge KW - tetromycin Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-141171 VL - 9 IS - 10 ER - TY - JOUR A1 - Pimentel-Elardo, Sheila M. A1 - Buback, Verena A1 - Gulder, Tobias A. M. A1 - Bugni, Tim S. A1 - Reppart, Jason A1 - Bringmann, Gerhard A1 - Ireland, Chris M. A1 - Schirmeister, Tanja A1 - Hentschel, Ute T1 - New Tetromycin Derivatives with Anti-Trypanosomal and Protease Inhibitory Activities N2 - Four new tetromycin derivatives, tetromycins 1–4 and a previously known one, tetromycin B (5) were isolated from Streptomyces axinellae Pol001T cultivated from the Mediterranean sponge Axinella polypoides. Structures were assigned using extensive 1D and 2D NMR spectroscopy as well as HRESIMS analysis. The compounds were tested for antiparasitic activities against Leishmania major and Trypanosoma brucei, and for protease inhibition against several cysteine proteases such as falcipain, rhodesain, cathepsin L, cathepsin B, and viral proteases SARS-CoV Mpro, and PLpro. The compounds showed antiparasitic activities against T. brucei and time-dependent inhibition of cathepsin L-like proteases with Ki values in the low micromolar range. KW - Biologie KW - tetromycin KW - anti-trypanosomal KW - protease inhibition KW - Streptomyces axinellae KW - marine sponge Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-75465 ER - TY - JOUR A1 - Pillai, Deepu R. A1 - Heidemann, Robin M. A1 - Kumar, Praveen A1 - Shanbhag, Nagesh A1 - Lanz, Titus A1 - Dittmar, Michael S. A1 - Sandner, Beatrice A1 - Beier, Christoph P. A1 - Weidner, Norbert A1 - Greenlee, Mark W. A1 - Schuierer, Gerhard A1 - Bogdahn, Ulrich A1 - Schlachetzki, Felix T1 - Comprehensive Small Animal Imaging Strategies on a Clinical 3 T Dedicated Head MR-Scanner; Adapted Methods and Sequence Protocols in CNS Pathologies JF - PLoS ONE N2 - Background: Small animal models of human diseases are an indispensable aspect of pre-clinical research. Being dynamic, most pathologies demand extensive longitudinal monitoring to understand disease mechanisms, drug efficacy and side effects. These considerations often demand the concomitant development of monitoring systems with sufficient temporal and spatial resolution. Methodology and Results: This study attempts to configure and optimize a clinical 3 Tesla magnetic resonance scanner to facilitate imaging of small animal central nervous system pathologies. The hardware of the scanner was complemented by a custom-built, 4-channel phased array coil system. Extensive modification of standard sequence protocols was carried out based on tissue relaxometric calculations. Proton density differences between the gray and white matter of the rodent spinal cord along with transverse relaxation due to magnetic susceptibility differences at the cortex and striatum of both rats and mice demonstrated statistically significant differences. The employed parallel imaging reconstruction algorithms had distinct properties dependent on the sequence type and in the presence of the contrast agent. The attempt to morphologically phenotype a normal healthy rat brain in multiple planes delineated a number of anatomical regions, and all the clinically relevant sequels following acute cerebral ischemia could be adequately characterized. Changes in blood-brain-barrier permeability following ischemia-reperfusion were also apparent at a later time. Typical characteristics of intracerebral haemorrhage at acute and chronic stages were also visualized up to one month. Two models of rodent spinal cord injury were adequately characterized and closely mimicked the results of histological studies. In the employed rodent animal handling system a mouse model of glioblastoma was also studied with unequivocal results. Conclusions: The implemented customizations including extensive sequence protocol modifications resulted in images of high diagnostic quality. These results prove that lack of dedicated animal scanners shouldn't discourage conventional small animal imaging studies. KW - Rat spinal-cord KW - Middle cerebral-artery KW - Blood-brain-barrier KW - Experimental intracerebral hemorrhage KW - Partially parallel acquisitions KW - Magnetic-resonance microscopy KW - IN-VIVO KW - Mouse-brain KW - Edema formation KW - White-matter Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-134193 VL - 6 IS - 2 ER - TY - JOUR A1 - Pham, Mirko A1 - Helluy, Xavier A1 - Kleinschnitz, Christoph A1 - Kraft, Peter A1 - Bartsch, Andreas J. A1 - Jakob, Peter A1 - Nieswandt, Bernhard A1 - Bendszus, Martin A1 - Guido, Stoll T1 - Sustained Reperfusion after Blockade of Glycoprotein-Receptor-Ib in Focal Cerebral Ischemia: An MRI Study at 17.6 Tesla JF - PLoS ONE N2 - Background: Inhibition of early platelet adhesion by blockade of glycoprotein-IB (GPIb) protects mice from ischemic stroke. To elucidate underlying mechanisms in-vivo, infarct development was followed by ultra-high field MRI at 17.6 Tesla. Methods: Cerebral infarction was induced by transient-middle-cerebral-artery-occlusion (tMCAO) for 1 hour in C57/BL6 control mice (N = 10) and mice treated with 100 mg Fab-fragments of the GPIb blocking antibody p0p/B 1 h after tMCAO (N = 10). To control for the effect of reperfusion, additional mice underwent permanent occlusion and received anti-GPIb treatment (N = 6; pMCAO) or remained without treatment (N = 3; pMCAO). MRI 2 h and 24 h after MCAO measured cerebral-blood-flow (CBF) by continuous arterial-spin labelling, the apparent-diffusion-coefficient (ADC), quantitative-T2 and T2-weighted imaging. All images were registered to a standard mouse brain MRI atlas and statistically analysed voxel-wise, and by cortico-subcortical ROI analysis. Results: Anti-GPIb treatment led to a relative increase of postischemic CBF vs. controls in the cortical territory of the MCA (2 h: 44.2 +/- 6.9 ml/100g/min versus 24 h: 60.5 +/- 8.4; p = 0.0012, F((1,18)) = 14.63) after tMCAO. Subcortical CBF 2 h after tMCAO was higher in anti-GPIb treated animals (45.3 +/- 5.9 vs. controls: 33.6 +/- 4.3; p = 0.04). In both regions, CBF findings were clearly related to a lower probability of infarction (Cortex/Subcortex of treated group: 35%/65% vs. controls: 95%/100%) and improved quantitative-T2 and ADC. After pMCAO, anti-GPIb treated mice developed similar infarcts preceded by severe irreversible hypoperfusion as controls after tMCAO indicating dependency of stroke protection on reperfusion. Conclusion: Blockade of platelet adhesion by anti-GPIb-Fab-fragments results in substantially improved CBF early during reperfusion. This finding was in exact spatial correspondence with the prevention of cerebral infarction and indicates in-vivo an increased patency of the microcirculation. Thus, progression of infarction during early ischemia and reperfusion can be mitigated by anti-platelet treatment. KW - Von-Willebrand-factor KW - Experimental stroke KW - Magnetic-resonance KW - Arterial water KW - Brain KW - Perfusion KW - Mice KW - Inflammation KW - Coefficient KW - mechanisms Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-142608 VL - 6 IS - 4 ER - TY - JOUR A1 - Pfister, Roland T1 - Wardrobe Malfunctions and the Measurement of Internet Behaviour N2 - The wardrobe malfunction—an unanticipated exposure of bodily parts in the public—has become a prevailing issue in concerts, shows and other celebrity events that is reliably reported by the media. The internet as the fastest source for celebrity gossip allows measuring the impact of such wardrobe malfunctions on the public in-terest in a celebrity. This measurement in turn allows conclusions about intention, motivation, and internet be-haviour of a wide variety of internet users. The present study exemplifies the use of an innovative non-reactive measure of active interest—the Search Volume Index—to assess the impact of a variety of internet-related phe-nomena, including wardrobe malfunctions. Results indicate that interest in a celebrity increases immediately af-ter such an event and stays at a high level for about three weeks (the wardrobe plateau). This special form of ce-lebrity gossip thus meets a constant interest of a substantial proportion of internet users. KW - Psychologie KW - Internet Behaviour KW - Search Volume Index KW - Non-reactive Measurement KW - Wardrobe Malfunction Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-69067 ER - TY - JOUR A1 - Petritsch, Bernhard A1 - Goltz, Jan Peter A1 - Hahn, Dietbert A1 - Wendel, Frank T1 - Extensive craniocervical bone pneumatization JF - Diagnostic and Interventional Radiology N2 - We report a case of extensive abnormal craniocervical bone pneumatization accidentally found in a patient without any history of trauma or surgery. The patient had only mild unspecific thoracic pain and bilateral paresthesia that did not correlate with computed tomography findings. KW - vertebral pneumaticity KW - sauropod dinosaurs KW - bone KW - skull KW - cervical vertebrae pneumatization Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-139349 VL - 17 IS - 4 ER - TY - JOUR A1 - Partho, Halder A1 - Chen, Yi-chun A1 - Brauckhoff, Janine A1 - Hofbauer, Alois A1 - Dabauvalle, Marie-Christine A1 - Lewandrowski, Urs A1 - Winkler, Christiane A1 - Sickmann, Albert A1 - Buchner, Erich T1 - Identification of Eps15 as Antigen Recognized by the Monoclonal Antibodies aa2 and ab52 of the Wuerzburg Hybridoma Library against Drosophila Brain JF - PLoS One N2 - The Wuerzburg Hybridoma Library against the Drosophila brain represents a collection of around 200 monoclonal antibodies that bind to specific structures in the Drosophila brain. Here we describe the immunohistochemical staining patterns, the Western blot signals of one- and two-dimensional electrophoretic separation, and the mass spectrometric characterization of the target protein candidates recognized by the monoclonal antibodies aa2 and ab52 from the library. Analysis of a mutant of a candidate gene identified the Drosophila homolog of the Epidermal growth factor receptor Pathway Substrate clone 15 (Eps15) as the antigen for these two antibodies. KW - neuropil KW - immunohistochemistry techniques KW - gel electrophoresis KW - immunoprecipitation KW - silver staining KW - drosophila melanogaster KW - antigen processing and recognition KW - hybridomas Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-137957 VL - 6 IS - 12 ER - TY - JOUR A1 - Pahl, Mario A1 - Zhu, Hong A1 - Tautz, Jürgen A1 - Zhang, Shaowu T1 - Large Scale Homing in Honeybees N2 - Honeybee foragers frequently fly several kilometres to and from vital resources, and communicate those locations to their nest mates by a symbolic dance language. Research has shown that they achieve this feat by memorizing landmarks and the skyline panorama, using the sun and polarized skylight as compasses and by integrating their outbound flight paths. In order to investigate the capacity of the honeybees’ homing abilities, we artificially displaced foragers to novel release spots at various distances up to 13 km in the four cardinal directions. Returning bees were individually registered by a radio frequency identification (RFID) system at the hive entrance. We found that homing rate, homing speed and the maximum homing distance depend on the release direction. Bees released in the east were more likely to find their way back home, and returned faster than bees released in any other direction, due to the familiarity of global landmarks seen from the hive. Our findings suggest that such large scale homing is facilitated by global landmarks acting as beacons, and possibly the entire skyline panorama. KW - Biene Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-68985 ER - TY - JOUR A1 - Ondrusch, Nicolai A1 - Kreft, Jürgen T1 - Blue and Red Light Modulates SigB-Dependent Gene Transcription, Swimming Motility and Invasiveness in Listeria monocytogenes N2 - Background: In a number of gram-positive bacteria, including Listeria, the general stress response is regulated by the alternative sigma factor B (SigB). Common stressors which lead to the activation of SigB and the SigB-dependent regulon are high osmolarity, acid and several more. Recently is has been shown that also blue and red light activates SigB in Bacillus subtilis. Methodology/Principal Findings: By qRT-PCR we analyzed the transcriptional response of the pathogen L. monocytogenes to blue and red light in wild type bacteria and in isogenic deletion mutants for the putative blue-light receptor Lmo0799 and the stress sigma factor SigB. It was found that both blue (455 nm) and red (625 nm) light induced the transcription of sigB and SigB-dependent genes, this induction was completely abolished in the SigB mutant. The blue-light effect was largely dependent on Lmo0799, proving that this protein is a genuine blue-light receptor. The deletion of lmo0799 enhanced the red-light effect, the underlying mechanism as well as that of SigB activation by red light remains unknown. Blue light led to an increased transcription of the internalin A/B genes and of bacterial invasiveness for Caco-2 enterocytes. Exposure to blue light also strongly inhibited swimming motility of the bacteria in a Lmo0799- and SigB-dependent manner, red light had no effect there. Conclusions/Significance: Our data established that visible, in particular blue light is an important environmental signal with an impact on gene expression and physiology of the non-phototrophic bacterium L. monocytogenes. In natural environments these effects will result in sometimes random but potentially also cyclic fluctuations of gene activity, depending on the light conditions prevailing in the respective habitat. KW - Listeria monocytogenes Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-75451 ER - TY - JOUR A1 - Ondrusch, Nicolai A1 - Kreft, Jürgen T1 - Blue and Red Light Modulates SigB-Dependent Gene Transcription, Swimming Motility and Invasiveness in \(Listeria\) \(monocytogenes\) JF - PLoS ONE N2 - Background: In a number of gram-positive bacteria, including Listeria, the general stress response is regulated by the alternative sigma factor B (SigB). Common stressors which lead to the activation of SigB and the SigB-dependent regulon are high osmolarity, acid and several more. Recently is has been shown that also blue and red light activates SigB in Bacillus subtilis. Methodology/Principal Findings: By qRT-PCR we analyzed the transcriptional response of the pathogen L. monocytogenes to blue and red light in wild type bacteria and in isogenic deletion mutants for the putative blue-light receptor Lmo0799 and the stress sigma factor SigB. It was found that both blue (455 nm) and red (625 nm) light induced the transcription of sigB and SigB-dependent genes, this induction was completely abolished in the SigB mutant. The blue-light effect was largely dependent on Lmo0799, proving that this protein is a genuine blue-light receptor. The deletion of lmo0799 enhanced the red-light effect, the underlying mechanism as well as that of SigB activation by red light remains unknown. Blue light led to an increased transcription of the internalin A/B genes and of bacterial invasiveness for Caco-2 enterocytes. Exposure to blue light also strongly inhibited swimming motility of the bacteria in a Lmo0799- and SigB-dependent manner, red light had no effect there. Conclusions/Significance: Our data established that visible, in particular blue light is an important environmental signal with an impact on gene expression and physiology of the non-phototrophic bacterium L. monocytogenes. In natural environments these effects will result in sometimes random but potentially also cyclic fluctuations of gene activity, depending on the light conditions prevailing in the respective habitat. KW - Gram-positive bacteria KW - Sigma(B)-dependent stress-response KW - Non-phototrophic bacteria KW - Prfa-mediated virulence KW - NTP-binding-properties KW - Bacillus-subtilis KW - Receptor ytva KW - Lov domain KW - Factor sigma(B) Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-134050 VL - 6 IS - 1 ER - TY - JOUR A1 - Ochman, S. A1 - Vordemvenne, T. A1 - Paletta, J. A1 - Raschke, M. J. A1 - Meffert, R. H. A1 - Doht, S. T1 - Experimental Fracture Model versus Osteotomy Model in Metacarpal Bone Plate Fixation JF - The Scientific World Journal N2 - Introduction Osteotomy or fracture models can be used to evaluate mechanical properties of fixation techniques of the hand skeleton in vitro. Although many studies make use of osteotomy models, fracture models simulate the clinical situation more realistically. This study investigates monocortical and bicortical plate fixation on metacarpal bones considering both aforementioned models to decide which method is best suited to test fixation techniques. Methods Porcine metacarpal bones (n =40) were randomized into 4 groups. In groups I and II bones were fractured with a modified 3-point bending test. The intact bones represented a further control group to which the other groups after fixation were compared. In groups III and IV a standard osteotomy was carried out. Bones were fixated with plates monocortically (group I, III) and bicortically (group II, IV) and tested for failure. Results Bones fractured at a mean maximum load of 482.8N±104.8N with a relative standard deviation (RSD) of 21.7%, mean stiffness was 122.3±35 N/mm. In the fracture model, there was a significant difference (P = 0.01) for maximum load of monocortically and bicortically fixed bones in contrast to the osteotomy model (P = 0.9). Discussion. In the fracture model, because one can use the same bone for both measurements in the intact state and the bone-plate construct states, the impact of inter-individual differences is reduced. In contrast to the osteotomy model there are differences between monocortical and bicortical fixations in the fracture model. Thus simulation of the in vivo situation is better and seems to be suitable for the evaluation of mechanical properties of fixation techniques on metacarpals KW - biomechanics KW - fracture model KW - metacarpal KW - osteotomy KW - plate fixation Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-178840 N1 - http://dx.doi.org/10.1100/2011/465371 VL - 11 ER - TY - JOUR A1 - Oberländer, Uwe A1 - Pletinckx, Katrien A1 - Dähler, Anja A1 - Müller, Nora A1 - Lutz, Manfred A1 - Arzberger, Thomas A1 - Riederer, Peter A1 - Gerlach, Manfred A1 - Koutsilieri, Eleni A1 - Scheller, Carsten T1 - Neuromelanin is an Immune Stimulator for Dendritic Cells in vitro N2 - Background: Parkinson’s disease (PD) is characterized at the cellular level by a destruction of neuromelanin (NM)-containing dopaminergic cells and a profound reduction in striatal dopamine. It has been shown recently that antimelanin antibodies are increased in sera of Parkinson patients, suggesting that NM may act as an autoantigen. In this study we tested whether NM is being recognized by dendritic cells (DCs), the major cell type for inducing Tand B-cell responses in vivo. This recognition of NM by DCs is a prerequisite to trigger an adaptive autoimmune response directed against NM-associated structures. Results: Murine DCs were treated with NM of substantia nigra (SN) from human subjects or with synthetic dopamine melanin (DAM). DCs effectively phagocytized NM and subsequently developed a mature phenotype (CD86high/MHCIIhigh). NM-activated DCs secreted the proinflammatory cytokines IL-6 and TNF-a. In addition, they potently triggered T cell proliferation in a mixed lymphocyte reaction, showing that DC activation was functional to induce a primary T cell response. In contrast, DAM, which lacks the protein and lipid components of NM but mimics the dopamine-melanin backbone of NM, had only very little effect on DC phenotype and function. Conclusions: NM is recognized by DCs in vitro and triggers their maturation. If operative in vivo, this would allow the DC-mediated transport and presentation of SN antigens to the adaptive immune system, leading to autoimmmunity in susceptible individuals. Our data provide a rationale for an autoimmune-based pathomechanism of PD with NM as the initial trigger. KW - Immunstimulation KW - Dendritische Zelle Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-69210 ER - TY - JOUR A1 - Niewalda, Thomas A1 - Völler, Thomas A1 - Eschbach, Claire A1 - Ehmer, Julia A1 - Wen-Chuang, Chou A1 - Timme, Marc A1 - Fiala, André A1 - Gerber, Bertram T1 - A Combined Perceptual, Physico-Chemical, and Imaging Approach to 'Odour-Distances' Suggests a Categorizing Function of the Drosophila Antennal Lobe JF - PLoS One N2 - How do physico-chemical stimulus features, perception, and physiology relate? Given the multi-layered and parallel architecture of brains, the question specifically is where physiological activity patterns correspond to stimulus features and/or perception. Perceived distances between six odour pairs are defined behaviourally from four independent odour recognition tasks. We find that, in register with the physico-chemical distances of these odours, perceived distances for 3octanol and n-amylacetate are consistently smallest in all four tasks, while the other five odour pairs are about equally distinct. Optical imaging in the antennal lobe, using a calcium sensor transgenically expressed in only first-order sensory or only second-order olfactory projection neurons, reveals that 3-octanol and n-amylacetate are distinctly represented in sensory neurons, but appear merged in projection neurons. These results may suggest that within-antennal lobe processing funnels sensory signals into behaviourally meaningful categories, in register with the physico-chemical relatedness of the odours. KW - organization KW - cameleon KW - honeybee KW - map KW - neurons KW - reveals KW - melanogaster KW - mushroom body KW - spatial representation KW - olfactory information Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-133510 VL - 6 IS - 9 ER -