Chinese Academy of Sciences

About: Chinese Academy of Sciences is a government organization based out in Beijing, Beijing, China. It is known for research contribution in the topics: Catalysis & Population. The organization has 421602 authors who have published 634849 publications receiving 14894293 citations. The organization is also known as: CAS.

MicroRNA Directs mRNA Cleavage of the Transcription Factor NAC1 to Downregulate Auxin Signals for Arabidopsis Lateral Root Development

Abstract: Although several plant microRNAs (miRNAs) have been shown to play a role in plant development, no phenotype has yet been associated with a reduction or loss of expression of any plant miRNA. Arabidopsis thaliana miR164 was predicted to target five NAM/ATAF/CUC (NAC) domain‐encoding mRNAs, including NAC1, which transduces auxin signals for lateral root emergence. Here, we show that miR164 guides the cleavage of endogenous and transgenic NAC1 mRNA, producing 39specific fragments. Cleavage was blocked by NAC1 mutations that disrupt base pairing with miR164. Compared with wildtype plants, Arabidopsis mir164a and mir164b mutant plants expressed less miR164 and more NAC1 mRNA and produced more lateral roots. These mutant phenotypes can be complemented by expression of the appropriate MIR164a and MIR164b genomic sequences. By contrast, inducible expression of miR164 in wild-type plants led to decreased NAC1 mRNA levels and reduced lateral root emergence. Auxin induction of miR164 was mirrored by an increase in the NAC1 mRNA 39 fragment, which was not observed in the auxin-insensitive mutants auxin resistant1 (axr1-12), axr2-1, and transport inhibitor response1. Moreover, the cleavage-resistant form of NAC1 mRNA was unaffected by auxin treatment. Our results indicate that auxin induction of miR164 provides a homeostatic mechanism to clear NAC1 mRNA to downregulate auxin signals.

Direct observation of catch bonds involving cell-adhesion molecules

Abstract: Bonds between adhesion molecules are often mechanically stressed. A striking example is the tensile force applied to selectin-ligand bonds, which mediate the tethering and rolling of flowing leukocytes on vascular surfaces(1-3). It has been suggested that

Photoassisted Degradation of Dye Pollutants. V. Self-Photosensitized Oxidative Transformation of Rhodamine B under Visible Light Irradiation in Aqueous TiO2 Dispersions

Abstract: Chemical oxygen demand (CODCr) and proton NMR, UV−vis, and spin trapping EPR spectroscopic evidence is presented to demonstrate the inverse photosensitized oxidative transformation of tetraethylated rhodamine (RhB) under visible illumination of aqueous titania dispersions. Both de-ethylation and oxidative degradation take place with the former proceeding in a stepwise manner to yield mono-, di-, tri-, and tetra-de-ethylated rhodamine species. Intermediates present after each de-ethylation step remain in a fast dynamic equilibrium between the titania particle surface and the bulk solution. The concentration of •OH radicals, formed from the inverse photosensitization process through the superoxide radical anion, increases upon addition of the anionic dodecylbenzene sulfonate surfactant (DBS) because a larger number of RhB excited states are able to inject an electron into the conduction band of the TiO2 particles. Also, intermediates that can no longer absorb the visible light, (i.e., once the dye solution ...