Compact x-ray microscope for the water window based on a high brightness laser plasma source.

We present a laser plasma based x-ray microscope for the water window employing a high-average power laser system for plasma generation. At 90 W laser power a brightness of 7.4 x 10(11) photons/(s x sr x μm(2)) was measured for the nitrogen Lyα line emission at 2.

Modulation of inositol 1,4,5-trisphosphate binding to the various inositol 1,4,5-trisphosphate receptor isoforms by thimerosal and cyclic ADP-ribose.

Three different genes encode the inositol 1,4,5-trisphosphate (IP3) receptor (IP3R), an intracellular Ca2+ channel involved in cellular Ca2+ signaling. The IP3-binding characteristics of the various IP3R isoforms differ, but until now no specific activators or inhibitors of IP3 binding have been described. We compared the effects of oxidizing reagents, in particular thimerosal, and of cyclic ADP-ribose (cADPR) on IP3 binding to the various IP3R isoforms.

Ca2+ and calmodulin differentially modulate myo-inositol 1,4, 5-trisphosphate (IP3)-binding to the recombinant ligand-binding domains of the various IP3 receptor isoforms.

We have expressed the N-terminal 581 amino acids of type 1 myo-inositol 1,4,5-trisphosphate receptor (IP(3)R1), IP(3)R2 and IP(3)R3 as recombinant proteins [ligand-binding site 1 (lbs-1), lbs-2, lbs-3] in the soluble fraction of Escherichia coli. These recombinant proteins contain the complete IP(3)-binding domain and bound IP(3) and adenophostin A with high affinity. Ca(2+) and calmodulin were previously found to maximally inhibit IP(3) binding to lbs-1 by 42+/-6 and 43+/-6% respectively, and with an IC(50) of approx.

Modulation of type 1, 2 and 3 inositol 1,4,5-trisphosphate receptors by cyclic ADP-ribose and thimerosal.

The binding of inositol 1,4,5-trisphosphate (IP3) to the IP3 receptor (IP3R) is modulated by various compounds. Until now, limited progress has been made concerning the isoform-specific effects of these modulators. In this study, we examined how [3H]IP3 binding to the three IP3R isoforms is modulated by cyclic ADP-ribose (cADPR) and by the SH-reagent thimerosal.

The bell-shaped Ca2+ dependence of the inositol 1,4, 5-trisphosphate-induced Ca2+ release is modulated by Ca2+/calmodulin.

Calmodulin inhibits inositol 1,4,5-trisphosphate (IP3) binding to the IP3 receptor in both a Ca2+-dependent and a Ca2+-independent way. Because there are no functional data on the modulation of the IP3-induced Ca2+ release by calmodulin at various Ca2+ concentrations, we have studied how cytosolic Ca2+ and Sr2+ interfere with the effects of calmodulin on the IP3-induced Ca2+ release in permeabilized A7r5 cells. We now report that calmodulin inhibited Ca2+ release through the IP3 receptor with an IC50 of 4.