Refine
Year of publication
Has Fulltext
- yes (800)
Is part of the Bibliography
- no (800)
Keywords
- Heavy Ion Experiments (16)
- Hadron-Hadron scattering (experiments) (11)
- LHC (9)
- Heavy-ion collision (6)
- ALICE experiment (4)
- Hadron-Hadron Scattering (4)
- Heavy Ions (4)
- ALICE (3)
- pp collisions (3)
- Aesculus hippocastanum (2)
Institute
- Physik (790)
- Frankfurt Institute for Advanced Studies (FIAS) (728)
- Informatik (696)
- Informatik und Mathematik (3)
- Hochschulrechenzentrum (2)
- Medizin (2)
- Georg-Speyer-Haus (1)
Chemo-communication is an important mode of interaction within ecosystem. The living organism in the ecosystem can deliver signals to conspecifics, to co-organisms, and unintentionally to their enemies, by emitting the volatile organic compounds (VOCs) to the atmosphere. There are some insect-fungi-associations displaying interesting relationships. For example, some bark beetle species (PAINE et al. 1997) introduce fungi into the conifers during the attack process. Fungi take advantage by associating with the insect in transport to new trees and passage through the bark. Insects may get advantage by feeding on fungi and overcoming the tree defence. Questions arise how fungus vectoring insects can recognize the weakness of defense mechanism in the case to introduce the fungus to the host tree and successfully overcome the remaining defence mechanisms. The interspecific communication among insects, fungi and host trees are not completely clarified, but there was the evidence that a number of forest scolytids including species in the genera Scolytus, Dendroctonus, Hylurgops, Trypodendron and Tomicus can be attracted to the host volatile compounds (BYERS 1995).
Since the 80s, the popular park- and city tree Aesculus hippocastanum has been infested with the leaf miner Cameraria ohridella (DESCHKA & DIMIC 1986). Additionally, the pathogenic fungi Guignardia aesculi causes leaf blotch disease and Erysiphe flexuosa causes powdery mildew on horse chestnuts. Often, all three diseases occur in parallel at the same leaves leading to a situation of competition. Moreover, recently some endophytic fungi were isolated from the leaf tissue of A. hippocastanum. In the present study, the volatile interaction between three trophic levels plant, insect, and fungi are discussed.
The blue pine wood borer (Phaenops cyanea) and the black pine sawyer beetle (Monochamus galloprovincialis) (Fig. 1) both are pests of the white pine (Pinus silvestris) and other Pinus species. Both insects have nearly the same demands regarding their breeding site. Larval development requires a fresh, unwilted inner bark. An infestation occurs on freshly cut trees or on trees suffering from stress (e.g. after dry seasons, loss of needles caused by feeding caterpillars or damage by forest fires). Phaenops cyanea detects susceptible pines by their volatile emissions (SCHÜTZ et al. 2004) and is able to infest the trees already at a low stress level. During feeding the larvae avoid the resin ducts of the tree and thus evade the oleoresin defence. The beetle is endemic in Europe and – under favourable climatic conditions – can cause substantial damage to pine forests. It is the most significant bark-breeding beetle of white pine in the lowlands of north-eastern Germany. Monochamus galloprovincialis is found in Europe and northern Africa. The larvae tend to a more copious feeding which makes them more susceptible to the oleoresin defence of the tree. Thus, M. galloprovincialis prefers trees that are weakened by a higher degree of stress. The economic damage caused by feeding of thebeetle is low. However, the beetle has gained a special attention of forest scientists because of its association with the nematode Bursaphelenchus xylophilus which is causing the pine wilt disease (PWD) in Pinus. The only outbreak of the PWD within Europe is limited to an area of 258.000 ha in Portugal. (MOTA et al. 1999).
Beginning in Belgium 1999, low mountain ranges of middle Europe were afflicted with the “European beech bark disease” (EBBD). It was first described by Hartig in 1878 as a complex disease where infestation of beech scale (Cryptococcus fagisuga; Hemiptera, Eriococcidae) is followed by fungal affection with Nectria coccinea and several white rot fungi. This often causes die back of mature beech trees, they tumble down and are colonised by woodbreeding beetles. Beside Belgium with 1 million cubic meter solid of beech wood (Fagus sylvatica); Luxembourg, France, and Southern Germany were affected in the last 6 years. In addition to known symptoms of EBBD, in all regions beech trees of an healthy appearance were surprisingly infested by the wood-breeding beetle Trypodendron domesticum. To understand mechanisms of this disease a chemo-ecological study was carried out, comparing the new phenomenon with the classical situation. A number of investigations of the involved beetles of the family of Scolytidae and Lymexylidae (BYERS 1992; KERCK 1976; KLIMETZEK 1984) suggest that the mechanisms of host-selection consist in the chemosensory differentiation of states of wood decay. The presence at the “border” between living and dying trees, T. domesticum turns out to be an interesting research object on xylobiont insects and physiological dying- and decaying-processes in trees. The underlying hypotheses of this work are: 1) Volatile organic compounds change successively during aging and decay of wood and characterise the most susceptible phase and breeding site for T. domesticum. 2) Volatiles released by trees afflicted by the new disease phenomenon are similar to volatiles of felled, susceptible deadwood
Cockchafers of the genus Melolontha (Coleoptera: Scarabaeidae) can be severe pests in forestry, agriculture and horticulture. Gradation of the two most important species, the forest cockchafer M. hippocastani FABR. and the European cockchafer M. melolontha L., occurs currently in several parts of central Europe. Orientation behaviour of the adult beetles has been the focus of recent studies (REINECKE et al. 2002 a, b, 2005). However, especially the larvae are dreaded because their belowground damage is not visible directly after feeding. There are a lot of speculations about belowground living insects and their way of living, but until now there were not that many experimental investigations. A rather unknown topic is the orientation behaviour of soil living organisms, which is also subject of some publications (HORBER 1954, HAUSS & SCHÜTTE 1976, HASLER 1986, HIBBARD et al. 1994, JEWETT & BJOSTAD 1996, BERNKLAU & BJOSTAD 1998A, BERNKLAU & BJOSTAD 1998B, BERNKLAU et al. 2005).
Pappeln wie die Zitterpappel (Populus tremula) bilden am Waldrand wichtige Habitate für Nachtfalter. Der Pappelschwärmer (Laothoe populi) und das Abendpfauenauge (Smerinthus ocellata) legen ihre Eier auf den Blättern ab. Als Nachtfalter sind sie auf andere Signale als die optischen angewiesen, um den optimalen Ovipositionsplatz zu finden. Je nach Vitalität des Baumes und seiner Exposition sind die entwicklungsbedingungen der Raupe verschieden. Diese Studie soll aufzeigen, welche Duftstoffe durch Änderungen der Vitalität des Baumes beeinflusst und welche durch die Nachtfalter wahrgenommen werden können.
The larval stages of Cameraria ohridella develop mining in leaves of the horse chestnut tree Aesculus hippocastanum. The insect establishes three generations in Central Europe. During the appearance of the first generation the horse chestnut trees bloom. Further on, parallel to the flying time of all generations other plant species bloom. The olfactory detection of flower odour compounds and the influence on oviposition of C. ohridella were examined using trace analytical and electrophysiological methods as well as bioassays.
Patients with ataxia-telangiectasia (A-T) suffer from progressive cerebellar ataxia, immunodeficiency, respiratory failure, and cancer susceptibility. From a clinical point of view, A-T patients with IgA deficiency show more symptoms and may have a poorer prognosis. In this study, we analyzed mortality and immunity data of 659 A-T patients with regard to IgA deficiency collected from the European Society for Immunodeficiencies (ESID) registry and from 66 patients with classical A-T who attended at the Frankfurt Goethe-University between 2012 and 2018. We studied peripheral B- and T-cell subsets and T-cell repertoire of the Frankfurt cohort and survival rates of all A-T patients in the ESID registry. Patients with A-T have significant alterations in their lymphocyte phenotypes. All subsets (CD3, CD4, CD8, CD19, CD4/CD45RA, and CD8/CD45RA) were significantly diminished compared to standard values. Patients with IgA deficiency (n = 35) had significantly lower lymphocyte counts compared to A-T patients without IgA deficiency (n = 31) due to a further decrease of naïve CD4 T-cells, central memory CD4 cells, and regulatory T-cells. Although both patient groups showed affected TCR-ß repertoires compared to controls, no differences could be detected between patients with and without IgA deficiency. Overall survival of patients with IgA deficiency was significantly diminished. For the first time, our data show that patients with IgA deficiency have significantly lower lymphocyte counts and subsets, which are accompanied with reduced survival, compared to A-T patients without IgA deficiency. IgA, a simple surrogate marker, is indicating the poorest prognosis for classical A-T patients. Both non-interventional clinical trials were registered at clinicaltrials.gov 2012 (Susceptibility to infections in ataxia-telangiectasia; NCT02345135) and 2017 (Susceptibility to Infections, tumor risk and liver disease in patients with ataxia-telangiectasia; NCT03357978)
Colorectal carcinoma (CRC) is a major cause of morbidity and mortality in Western countries. It has so far been molecularly defined mainly by alterations of the Wnt pathway. We show here for the first time that aberrant activities of the signal transducer and activator of transcription STAT3 actively contribute to this malignancy and, thus, are a potential therapeutic target for CRC. Constitutive STAT3 activity was found to be abundant in dedifferentiated cancer cells and infiltrating lymphocytes of CRC samples, but not in non-neoplastic colon epithelium. Cell lines derived from malignant colorectal tumors lost persistent STAT3 activity in culture. However, implantation of colon carcinoma cells into nude mice resulted in restoration of STAT3 activity, suggesting a role of an extracellular stimulus within the tumor microenvironment as a trigger for STAT activation. STAT3 activity in CRC cells triggered through interleukin-6 or through a constitutively active STAT3 mutant promoted cancer cell multiplication, whereas STAT3 inhibition through a dominant-negative variant impaired IL-6-driven proliferation. Blockade of STAT3 activation in CRCderived xenograft tumors slowed down their development, arguing for a contribution of STAT3 to colorectal tumor growth.
Anaphylactic shock is a severe allergic reaction involving multiple organs including the bronchial and cardiovascular system. Most anaphylactic mediators, like platelet-activating factor (PAF), histamine, and others, act through G protein – coupled receptors, which are linked to the heterotrimeric G proteins Gq /G 11 , G12/G13 , and Gi . The role of downstream signaling pathways activated by anaphylactic mediators in defi ned organs during anaphylactic reactions is largely unknown. Using genetic mouse models that allow for the conditional abrogation of G q /G 11 - and G 12 /G 13 -mediated signaling pathways by inducible Cre/loxP-mediated mutagenesis in endothelial cells (ECs), we show that Gq /G11 -mediated signaling in ECs is required for the opening of the endothelial barrier and the stimulation of nitric oxide formation by various infl ammatory mediators as well as by local anaphylaxis. The systemic effects of anaphylactic mediators like histamine and PAF, but not of bacterial lipopolysaccharide (LPS), are blunted in mice with endothelial G alpha q/G alpha 11 deficiency. Mice with endothelium-specific G alpha q /G alpha 11 deficiency, but not with G alpha 12/G alpha 13 deficiency, are protected against the fatal consequences of passive and active systemic anaphylaxis. This identifies endothelial Gq/G11 -mediated signaling as a critical mediator of fatal systemic anaphylaxis and, hence, as a potential new target to prevent or treat anaphylactic reactions.