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Jürgen Rheinlaender Jun-Xian Shen Heiner Römer 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2006,192(4):389-397
Pair formation in the bushcricket Gampsocleis gratiosa is achieved through acoustic signalling by the male and phonotactic approaches of the female towards the calling song. On
a walking belt in the free sound field, females tracked the position of the speaker broadcasting the male calling song with
a remarkable precision, deviating by no more than 10 cm in either direction from the ideal course. Starting with stimulus
angles of 6–10° the females significantly turned to the correct side, and with stimulus angles greater than 25° no incorrect
turns were made. Using neurophysiological data on the directionality of the ear we calculated that with such stimulus angles
the available binaural intensity difference is in the order of 1–2 dB. We developed a dichotic ear stimulation device for
freely moving females with a cross-talk barrier of about 50 dB, which allowed to precisely apply small binaural intensity
differences. In such a dichotic stimulation paradigm, females on average turned to the tronger stimulated side starting with
a 1 dB difference between both ears. The significance of such a reliable lateralization behaviour with small interaural intensity
differences for phonotactic behaviour under natural conditions is discussed. 相似文献
75.
The AidB component of the Escherichia coli adaptive response to alkylating agents is a flavin-containing, DNA-binding protein 下载免费PDF全文
Upon exposure to alkylating agents, Escherichia coli increases expression of aidB along with three genes (ada, alkA, and alkB) that encode DNA repair proteins. In order to begin to identify the role of AidB in the cell, the protein was purified to homogeneity, shown to possess stoichiometric amounts of flavin adenine dinucleotide (FAD), and confirmed to have low levels of isovaleryl-coenzyme A (CoA) dehydrogenase activity. A homology model of an AidB homodimer was constructed based on the structure of a four-domain acyl-CoA oxidase. The predicted structure revealed a positively charged groove connecting the two active sites and a second canyon of positive charges in the C-terminal domain, both of which could potentially bind DNA. Three approaches were used to confirm that AidB binds to double-stranded DNA. On the basis of its ability to bind DNA and its possession of a redox-active flavin, AidB is predicted to catalyze the direct repair of alkylated DNA. 相似文献
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Appel H Loddenkemper C Grozdanovic Z Ebhardt H Dreimann M Hempfing A Stein H Metz-Stavenhagen P Rudwaleit M Sieper J 《Arthritis research & therapy》2006,8(5):R143-7
Ankylosing spondylitis (AS) is a chronic inflammatory disease which affects primarily the sacroiliac joints and the spine.
In patients with active disease, magnetic resonance imaging (MRI) of the spine shows areas of bone marrow edema, the histopathological
equivalent of which is unknown. In this study we correlate inflammation in the spine of patients with AS as revealed by histological
examination with bone marrow edema as detected by MRI. We have compared the histopathological findings of zygapophyseal joints
from 8 patients with AS (age: 30 to 64, disease duration 7 to 33 years) undergoing spinal surgery with findings in MRI. For
histopathological analysis, we quantified infiltrates of CD3+, CD4+ and CD8+ T cells as well as CD20+ B cells immunohistochemically.
Bone marrow edema was evaluated in hematoxylin and eosin stained sections and quantified as the percentage of the bone marrow
area involved. All patients with AS showed interstitial mononuclear cell infiltrates and various degrees of bone marrow edema
(range from 10% to 60%) in histopathological analysis. However, in only three of eight patients histopathological inflammation
and edema in the zygapophyseal joints correlated with bone marrow edema in zygapophyseal joints of the lumbar spine as detected
by MRI. Interestingly, two of these patients showed the highest histological score for bone marrow edema (60%). This first
study correlating histopathological changes in the spine of patients with AS with findings in MRI scans suggests that a substantial
degree of bone marrow inflammation and edema is necessary to be detected by MRI. 相似文献
78.
Barth M Rickelt S Noffz E Winter-Simanowski S Niemann H Akhyari P Lichtenberg A Franke WW 《Cell and tissue research》2012,348(2):295-307
The interstitial cells of cardiac valves represent one of the most frequent cell types in the mammalian heart. In order to provide a cell and molecular biological basis for the growth of isolated valvular interstitial cells (VICs) in cell culture and for the use in re-implantation surgery we have examined VICs in situ and in culture, in fetal, postnatal and adult hearts, in re-associations with scaffolds of extracellular matrix (ECM) material and decellularized heart valves. In all four mammalian species examined (human, bovine, porcine and ovine), the typical mesenchymal-type cell-cell adherens junctions (AJs) connecting VICs appear as normal N-cadherin based puncta adhaerentia. Their molecular ensemble, however, changes under various growth conditions insofar as plakophilin-2 (Pkp2), known as a major cytoplasmic plaque component of epithelial desmosomes, is recruited to and integrated in the plaques of VIC-AJs as a major component under growth conditions characterized by enhanced proliferation, i.e., in fetal heart valves and in cell cultures. Upon re-seeding onto decellularized heart valves or in stages of growth in association with artificial scaffolds, Pkp2 is - for the most part - lost from the AJs. As Pkp2 has recently also been detected in AJs of cardiac myxomata and diverse other mesenchymal tumors, the demonstrated return to the normal Pkp2-negative state upon re-association with ECM scaffolds and decellularized heart valves may now provide a safe basis for the use of cultured VICs in valve replacement surgery. Even more surprising, this type of transient acquisition of Pkp2 has also been observed in distinct groups of endothelial cells of the endocardium, where it seems to correspond to the cell type ready for endothelial-mesenchymal transition (EMT). 相似文献
79.
Mapping a songbird fauna with pupils How to induce pupils aged 13 to 14 years to successfully map the songbird fauna of a city park? The mapping project took place within 1.5 hours on an April morning. Pupils were organized as small working groups using maps, binoculars, and field guides produced by themselves. The project had been prepared by a 6 lesson course. Results were later discussed with nature conservancy officials. Pupils having participated in the project displayed increased knowledge of birds and motivation to observe them. 相似文献
80.
Glass TR Rotger M Telenti A Decosterd L Csajka C Bucher HC Günthard HF Rickenbach M Nicca D Hirschel B Bernasconi E Wandeler G Battegay M Marzolini C;Swiss HIV Cohort Study 《PloS one》2012,7(1):e29186