An emerging deep eutectic solvent based on halogen-bonds.

A new deep eutectic solvent (DES) driven by halogen bonding (XB) was exploited. A family of eutectic mixtures in the liquid state was obtained by the combination of quaternary ammonium salts and dihalogens. The formation mechanism was discussed based on experiments and DFT calculations. It not only broadens the potential DES systems but unlocks the possibility of XB complexes as solvents.

Dynamic evolution and scenario simulation of habitat quality under the impact of land-use change in the Huaihe River Economic Belt, China.

Habitat quality is an important indicator for evaluating the biodiversity provided by ecosystem. Estimating and scenario-simulating the dynamic evolution and future development trends of habitat quality under the influence of land-use change is significant in regional biodiversity conservation, formulating land-use planning, and maintaining the ecological environmental sustainability. In this article, we included the Huaihe River Economic Belt as the area of study because of its vital location in China and applied the CA-Markov and InVEST models to analyze the spatio-temporal evolution of habitat quality and to simulate the future development trends of habitat quality under three different land-use scenarios: fast urban growth scenario, farmland conservation-oriented scenario, and ecological conservation-oriented scenario. The results showed that the land-use change in the Huaihe River Economic Belt was mostly represented by the continuous increase of the built-up area, whereas other land types all declined in area from 1995 to 2015. The land-use changes under these three abovementioned alternative future scenarios with different development orientations were considerably different. The built-up area has been shown to expand rapidly to occupy other land types on a large scale under the fast urban growth scenario. Urban land increased slightly and a large area of rural residential land would be converted into farmland under the farmland conservation-oriented scenario. The built-up area and farmland might decrease while woodland, grassland and water would increase in extent of areas under the ecological conservation-oriented scenario. Habitat quality has been shown to be generally poor, continuing to decline from 1995 to 2015, while its spatial distribution was higher in the southwest and northeast areas and lower in the central regions. The future habitat quality would display a downward trend under the fast urban growth and farmland conservation-oriented scenarios with a further deterioration of the ecological environment, while the ecological conservation-oriented scenario predicted the converse trend that the ecological environment would be improved productively. This study may be useful for understanding the impact of land-use dynamics on biodiversity. The research results can provide a scientific basis for the decision-makers to formulate biodiversity conservation and land management policies.

Decreased grain size1, a C3HC4-type RING protein, influences grain size in rice (Oryza sativa L.).

KEY MESSAGE: We reported that DGS1 plays a positive role in regulating grain size in rice and was regulated by OsBZR1. Grain size is an important agronomic trait that contributes to grain yield. However, the underlying molecular mechanisms that determine final grain size are still largely unknown. We isolated a rice mutant showing reduced grain size in a 60Co-irradiated variety Nanjing 35 population. We named the mutant decreased grain size1 (dgs1). Map-based cloning and subsequent transgenic CRISPR and complementation assays indicated that a mutation had occurred in LOC_Os03g49900 and that the DGS1 allele regulated grain size. DGS1 encodes a protein with a 7-transmembrane domain and C3HC4 type RING domain. It was widely expressed, especially in young tissues. DGS1 is a membrane-located protein. OsBZR1 (BRASSINAZOLE-RESISTANT1), a core transcription activator of BR signaling, also plays a positive role in grain size. We provided preliminary evidence that OsBZR1 can bind to the DGS1 promoter to activate expression of DGS1.

Mechanistic insights into dioxygen activation by a manganese corrole complex: a broken-symmetry DFT study.

The Mn-oxygen species have been implicated as key intermediates in various Mn-mediated oxidation reactions. However, artificial oxidants were often used for the synthesis of the Mn-oxygen intermediates. Remarkably, the Mn(v)-oxo and Mn(iv)-peroxo species have been observed in the activation of O2 by Mn(iii) corroles in the presence of base (OH-) and hydrogen donors. In this work, density functional theory methods were used to get insight into the mechanism of dioxygen activation and formation of Mn(v)-oxo. The results demonstrated that the dioxygen cannot bind to Mn without the axial OH- ligand. Upon the addition of the axial OH- ligand, the dioxygen can bind to Mn in an end-on fashion to give the Mn(iv)-superoxo species. The hydrogen atom transfer from the hydrogen donor (substrate) to the Mn(iv)-superoxo species is the rate-limiting step, having a high reaction barrier and a large endothermicity. Subsequently, the O-C bond formation is concerted with an electron transfer from the substrate radical to the Mn and a proton transfer from the hydroperoxo moiety to the nearby N atom of the corrole ring, generating an alkylperoxo Mn(iii) complex. The alkylperoxo O-O bond cleavage affords a Mn(v)-oxo complex and a hydroxylated substrate. This novel mechanism for the Mn(v)-oxo formation via an alkylperoxo Mn(iii) intermediate gives insight into the O-O bond activation by manganese complexes.

Rice OsBT1 regulates seed dormancy through the glycometabolism pathway.

Seed dormancy and germination in rice (Oryza sativa L.) are complex and important agronomic traits that involve a number of physiological processes and energy. A mutant named h470 selected from a60Co-radiated indica cultivar N22 population had weakened dormancy that was insensitive to Gibberellin (GA) and Abscisic acid (ABA). The levels of GA4 and ABA were higher in h470 than in wild-type (WT) plants. The gene controlling seed dormancy in h470 was cloned by mut-map and transgenesis and confirmed to encode an ADP-glucose transporter protein. A 1 bp deletion in Os02g0202400 (OsBT1) caused the weaker seed dormancy in h470. Metabolomics analyses showed that most sugar components were higher in h470 seeds than the wild type. The mutation in h470 affected glycometabolism.

Ginkgo biloba extract improves brain uptake of ginsenosides by increasing blood-brain barrier permeability via activating A1 adenosine receptor signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Ginkgo biloba leaves and Panax ginseng are Chinese medicine commonly used in combination for cerebral disease. AIM OF THE STUDY: To investigate the effect of standard extract of Ginkgo biloba leaves (EGb) on facilitating brain uptake of ginsenoside and its underlying mechanisms. MATERIALS AND METHODS: The increasing uptake of ginsenosides in the brain of rats by EGb were detected by LC-MS/MS analysis. Evans blue and FITC-dextran leakage were determined to evaluate blood-brain barrier (BBB) permeability in vivo. Transendothelial electrical resistance (TEER) and Na-F penetration rate were measured with a co-culture of the human cerebral microvascular endothelial cell line (hCMEC/D3) and human normal glial cell line (HEB) in vitro BBB model. WB were used to analyzed the expression of BBB tight junctions (TJs) related protein (ZO-1, Occludin, Claudin-3, p-ERM, and p-MLC), ultrastructure of TJs was determined by transmission electron microscope. RESULTS: LC-MS/MS analysis demonstrated that EGb could improve brain uptake of ginsenoside Rg1, Re, Rd and Rb1. In vivo study showed that, BBB permeability was significantly increased after EGb administration, evidenced by the markedly increased penetration of FITC-dextran and Evans Blue into the mice brain parenchyma. In the in vitro BBB model, reduced TEER and increased Na-F penetration rate was observed in EGb group, which was associated with alteration of TJs ultrastructure. Furthermore, the expression of p-ERM and p-MLC in hCMEC/D3 as well as mice brain microvessels were significantly upregulated, but no significant change on the expression of TJs proteins (ZO-1, Occludin and Claudin-3). Moreover, the effect of EGb on in vitro BBB permeability and ERM, MLC phosphorylation was counteracted by DPCPX, an A1 adenosine receptor (A1R) antagonist. CONCLUSIONS: EGb might induce ERM/MLC phosphorylation and increase the cell-cell junction gaps to cause a reversible increase of the BBB permeability via A1R signaling pathway. Our results may contribute to better use of EGb in the treatment of brain diseases.