Synthesis and Evaluation of MGB Polyamide-Oligonucleotide Conjugates as Gene Expression Control Compounds.

MGB polyamide-oligonucleotide conjugates ON 1-4 with linked MGB polyamides at the 2-exocyclic amino group of a guanine base using aminoalkyl linkers were synthesized and evaluated in terms of binding affinity for complementary DNA containing the MGB polyamide binding sequence using T m and CD analyses. The MGB polyamides comprised pyrrole polyamides (Py4- and Py3-), which possess binding affinity for A-T base pairs, and imidazole (Im3-) and pyrrole-γ-imidazole (Py3-γ-Im3-) polyamide hairpin motifs, which possess binding affinity for C-G base pairs. It was found that the stability of modified dsDNA was greatly influenced by the linker length. Py4- and Py3-oligonucleotide conjugates (ON 1 (n = 4) and ON 2 (n = 4)) containing the 4-aminobutyl linker formed stable dsDNA with complementary DNA. Although Im3-oligonucleotide conjugate ON 3 (n = 4) containing the 4-aminobutyl linker formed stable dsDNA with complementary DNA, stabilization of dsDNA by the imidazole amide moiety of ON 3 (n = 4) was lower compared with the pyrrole amide moiety of ON 2 (n = 4). The Py3-γ-Im3-oligonucleotide conjugate ON 4 (n = 2), which possesses binding affinity for C-G base pairs via a pyrrole/imidazole combination and contains a 2-aminoethyl linker, showed high binding ability for complementary DNA. Furthermore, the DNA sequence recognition of MGB polyamide-oligonucleotide conjugates was investigated using single-base mismatch DNAs, which possess a mismatch base in the MGB polyamide binding sequence. The Py3-γ-Im3-oligonucleotide conjugate ON 4 (n = 2) showed high sequence recognition ability for complementary DNA.

Potential Anti-allergic Effects of Bibenzyl Derivatives from Liverworts, Radula perrottetii.

The liverwort Radula perrottetii contains various bibenzyl derivatives which are known to possess various biological activities, such as anti-inflammatory effects. Mast cells (MC) play crucial roles in allergic and inflammatory diseases; thus, inhibition of MC activation is pivotal for the treatment of allergic and inflammatory disorders. We investigated the effects of perrottetin D (perD), isolated from Radula perrottetii, and perD diacetate (Ac-perD) on antigen-induced activation of MCs. Bone marrow-derived MCs (BMMCs) were generated from C57BL/6 mice. The degranulation ratio, histamine release, and the interleukin (IL)-4 and leukotriene B4 productions on antigen-triggered BMMC were investigated. Additionally, the effects of the bibenzyls on binding of IgE to FcεRI were observed by flow cytometry, and signal transduction proteins was examined by Western blot. Furthermore, binding of the bibenzyls to the Fyn kinase domain was calculated. At 10 µM, perD decreased the degranulation ratio (p < 0.01), whereas 10 µM Ac-perD down-regulated IL-4 production (p < 0.05) in addition to decreasing the degranulation ratio (p < 0.01). Both compounds tended to decrease histamine release at a concentration of 10 µM. Although 10 µM perD reduced only Syk phosphorylation, 10 µM Ac-perD diminished phosphorylation of Syk, Gab2, PLC-γ, and p38. PerD appeared to selectively bind Fyn, whereas Ac-perD appeared to act as a weak but broad-spectrum inhibitor of kinases, including Fyn. In conclusion, perD and Ac-perD suppressed the phosphorylation of signal transduction molecules downstream of the FcεRI and consequently inhibited degranulation, and/or IL-4 production. These may be beneficial potential lead compounds for the development of novel anti-allergic and anti-inflammatory drugs.

Proton Order toward the Surface of Ice Ih Revealed by Heterodyne-Detected Sum Frequency Generation Spectroscopy.

Using heterodyne-detected sum frequency generation (HD-SFG) spectroscopy, we investigated surface proton order at the basal, primary prism, and secondary prism faces of single-crystalline ice Ih at ca. 130 K. The complex phase of the obtained spectra clearly indicates that second-order nonlinear polarization from which the HD-SFG signal arises is generated exclusively at the surfaces. This suggests surface proton ordering along the normal, whereas the bulk remains proton-disordered, as is well known for ice Ih. A strong positive peak observed in the HD-SFG spectra enables us to determine the "direction" of the surface proton order as "H-up", that is, the hydrogen atom of the OH group pointing away from the bulk, irrespective of the ice faces. Reliable HD-SFG measurements carried out in the present study have greatly advanced our understanding of surface structure of ice Ih.

Coordination between bZIP28 and HSFA2 in the regulation of heat response signals in Arabidopsis.

Heat stress can have detrimental effects on yield production worldwide. Although bZIP28 and HSFA2 were identified as putative heat sensors in plants, coordination between them has not been uncovered. In this study, the deficiency in bZIP28 did not affect heat tolerance in plants. However, the plants lacking bZIP28 showed enhanced activation of APXs-, MBF1c-and HSPs-dependent pathways as well as higher level of HsfA2 transcripts and H2O2 accumulation, suggesting that these pathways might compensate for the deficiency in bZIP28 during heat stress. In addition, requirement of HSFA2 for the activation of APXs-dependent pathway during heat stress was supported by the analyses of plants lacking HSFA2. Our study demonstrated the flexible mode of heat response pathways involving bZIP28, HSFA2 and ROS-dependent signals.