The immunoglobulin G (IgG)-containing B lymphocyte antigen receptor (IgG-BCR) transmits a signal distinct from that of IgM-BCR or IgD-BCR, although all three use the same signal-transducing ...component, Igα/Igβ. Here we demonstrate that the inhibitory coreceptor CD22 down-modulates signaling through IgM-BCR and IgD-BCR, but not that through IgG-BCR, because of the IgG cytoplasmic tail, which prevents CD22 phosphorylation. These results suggest that the cytoplasmic tail of IgG specifically enhances IgG-BCR signaling by preventing CD22-mediated signal inhibition. Enhanced signaling through IgG-BCR may be involved in efficient IgG production, which is crucial for immunity to pathogens.
The high heparin affinity subtype C of the secretory enzyme extracellular superoxide dismutase (EC-SOD) exists in the body mainly complexed with extracellular sulfated glycosaminoglycans (SGAGs).
...Addition of sulfated polysaccharides to EC-SOD C resulted in a prompt partial inhibition of the enzymic activity, in most cases amounting to 10-17%, but with the large dextran sulfate 500,000 amounting to 35%. Complex formation between heparin and EC-SOD C could also be observed as increases in apparent molecular weight of the enzyme. The findings suggest that the binding sites for SGAGs on EC-SOD C are localized far from the active site and that EC-SOD in vivo associated with SGAGs should retain the major part of its enzymic activity.
Studies with amino acid-specific reagents suggested that both lysine and arginine residues are involved in the binding of SGAGs. In particular, modification of only a few lysine residues/subunit resulted in loss of high SGAG affinity, whereas arginine modification resulted in loss of not only SGAG affinity but also enzymic activity. We propose that this is due to modification of Arg-186, which is homologous to the highly conserved arginine in the entrance to the active site of the copperzinc-SODs.
Extracellular-superoxide dismutase (EC-SOD) is one of the three SOD isozymes in humans and has affinity for heparin-like sulfated glycosaminoglycans in the extracellular matrix. The C-terminal ...portion of EC-SOD is responsible for the heparin-affinity of this enzyme, but this portion should be a target of proteinases. Recently, Oury et al. reported that EC-SOD is localized within the cytoplasm of neuronal cells, while this enzyme is found in the extracellular matrix in most other tissues. It has been speculated that the heparin-binding domain of EC-SOD in the brain is sensitive to proteolysis, which may result in a loss of extracellular immunoreactivity. This study was performed to investigate the heparin-affinity of EC-SOD in the human brain. We found that human EC-SOD in brain tissue has high heparin-affinity similar to that in the umbilical cord. Moreover, heparin-affinity of EC-SOD in brain homogenate was not decreased by incubation at 37°C for 72 h. The proteolytic activity in brain homogenate might be less than that in umbilical cord homogenates. The intracellular localization of EC-SOD could contribute to its slow clearance from the brain and maintenance of its physiological functions in the brain.
The process of recovery from mental suffering Adachi, T.; Kono, S.
Neuropsychiatrie de l'enfance et de l'adolescence,
July 2012, 2012-07-00, Letnik:
60, Številka:
5
Journal Article
Development of a PMT and DAQ system for neutron detection Hirota, K; Sakai, K; Sato, S ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2004, Letnik:
529, Številka:
1
Journal Article
Recenzirano
A scintillating detector and its data acquisition system are being developed for neutron scattering experiments. An Anger camera with a 64-channel flat panel PMT is used. The fast DAQ system ...discriminated and eliminated noise events from neutron events. WLS materials are being developed to use high quantum efficiency PMT.
We proposed a method to improve signal–noise ratio of the Fresnel-type neutron lens. The Gd mask of concentric circle thin layer reduced 80% noise, at the best, due to the Fresnel-type lens shape. As ...the transmission for
1.1
nm
neutrons decreased from 0.83 to 0.79 by using the Gd mask, the loss was 0.04.
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