Nitric oxide (NO) is an important signaling molecule involved in many physiological processes in plants. Nitric oxide generation and flavonoid accumulation are two early reactions of plants to ultraviolet-B (UV-B) irradiation. However, the source of UV-B-triggered NO generation and the role of NO in UV-B-induced flavonoid accumulation are not fully understood. In order to evaluate the origin of UV-B-triggered NO generation, we examined the responses of nitrate reductase (NR) activity and the expression levels of NIA1 and NIA2 genes in leaves of Betula pendula Roth (silver birch) seedlings to UV-B irradiation. The data show that UV-B irradiation stimulates NR activity and induces up-regulation of NIA1 but does not affect NIA2 expression during UV-B-triggered NO generation. Pretreatment of the leaves with NR inhibitors tungstate (TUN) and glutamine (Gln) abolishes not only UV-B-triggered NR activities but also UV-B-induced NO generation. Furthermore, application of TUN and Gln suppresses UV-B-induced flavonoid production in the leaves and the suppression of NR inhibitors on UV-B-induced flavonoid production can be reversed by NO via its donor sodium nitroprusside. Together, the data indicate that NIA1 in the leaves of silver birch seedlings is sensitive to UV-B and the UV-B-induced up-regulation of NIA1 may lead to enhancement of NR activity. Furthermore, our results demonstrate that NR is involved in UV-B-triggered NO generation and NR-mediated NO generation is essential for UV-B-induced flavonoid accumulation in silver birch leaves.
A fluorogenic and visual probe was devised to detect diethyl chlorophosphate (DCP), a nerve agent simulant. The probe, N-(rhodamine B)-lactam-2-aminoethanol (RB-AE), undergoes oxazoline formation following phosphorylation in the presence of DCP, which gives rapid and clear fluorescence and color change in the assay solutions.
Two electroactive materials, M1 and M2, are synthesized and their fluorescent electropolymerized (EP) films are prepared and used to detect metal ions. From the tested metal ions, M1 and M2 are demonstrated to be sensitive and selective for Fe(3+) ions. In particular, M2 exhibits higher sensitivity towards Fe(3+) ions. The fluorescent detection ranges from 10(-5) M to 4×10(-4) M. The excellent performance of the EP fluorescent films is mainly due to the strong metal-chelated properties of M2 and the intrinsic porous cross-linked-network microstructure of the EP films. This study, thus, provides a promising Fe(3+) sensing candidate and a potential preparation method for fluorescent sensing films.
Urolithiasis is a common disease that affects more than 5% to 8.8% of the world population with high recurring frequency. There are urgent needs for rapid and efficient diagnostics of...
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