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DNA methylation, a conserved epigenetic mark, is critical for tuning temporal and spatial gene expression. The Arabidopsis thaliana DNA glycosylase/lyase REPRESSOR OF SILENCING 1 (ROS1) initiates active DNA demethylation and is required to prevent DNA hypermethylation at thousands of genomic loci. However, how ROS1 is recruited to specific loci is not well understood. Here, we report the discovery of Arabidopsis AGENET Domain Containing Protein 3 (AGDP3) as a cellular factor that is required to prevent gene silencing and DNA hypermethylation. AGDP3 binds to H3K9me2 marks in its target DNA via its AGD12 cassette. Analysis of the crystal structure of the AGD12 cassette of AGDP3 in complex with an H3K9me2 peptide revealed that dimethylated H3K9 and unmodified H3K4 are specifically anchored into two different surface pockets. A histidine residue located in the methyllysine binding aromatic cage provides AGDP3 with pH-dependent H3K9me2 binding capacity. Our results uncover a molecular mechanism for the regulation of DNA demethylation by the gene silencing mark H3K9me2.

Hybrid ablation combines the advantages of surgical and catheter ablation. Many studies have explored the efficiency and safety of hybrid ablation in patients with nonparoxysmal AF.We systematically searched for prospective controlled trials that compared hybrid ablation with catheter/surgical ablation in PubMed, Web of Science, Wiley Library, and CNKI. Our main assessment indicators included maintenance of sinus rhythm (SR) without antiarrhythmic drugs for more than 12 months, major adverse events (MAEs), procedure time and fluoroscopy time.Of 1214 identified studies, five were eligible and were included in our analysis (N = 451 participants). The pooled results showed that hybrid ablation was more effective in maintaining SR than a single procedure (surgical ablation or catheter ablation) (OR = 2.52, 95% confidence interval [CI]: 1.63-3.89, p .001). Little significant heterogeneity was revealed (p = .32 for heterogeneity, IHybrid ablation was more effective than catheter ablation and was as effective as surgical ablation in patients with nonparoxysmal AF. Meanwhile, hybrid ablation, especially concomitant hybrid ablation, increases the incidence of MAEs and prolongs the procedure time.

Commercial bone substitute, such as calcined bovine bone (CBB), is currently extensively used as an alternative to autogenous bone. However, CBB lacks osteoinductivity and merely serves as a scaffold for native bone formation. To address this issue, we designed and prepared a heptaglutamate (E7)-modified BMP2-mimicking peptide (7E) and carried out a series of comprehensive physical characterizations and in vivo and in vitro studies to evaluate its role in the repair of cranial defects. The data elucidated that the amount of peptide anchoring to the bone graft materials was remarkably increased after modified with E7. Of note, 7E had a relatively stable and durable release, which promoted the osteogenic differentiation of rat derived bone marrow mesenchymal stem cells (BMSCs) and enhanced the bone regeneration of a rabbit calvarial defect by regulating the expression of the Runx2/SP7 axis. In summary, the composite biomaterials incorporating the E7-modified BMP2-mimicking peptide and CBB prepared in this study is a novel bone augmentation material with the merits of non-immunotoxicity, convenience, and low cost. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 108B:80-93, 2020.

In article number 2001410, Chaoran Ren, Shifeng Zhou, and co‐workers report a category of tiny fiber probes with metal electrodes regularly embedded inside the double‐clad biocompatible polymer fiber. This arrangement enables a probe with excellent mechanical properties, high transmission, and low impedance, which can realize long‐term simultaneous optical stimulation and neural recording at the single‐cell level in behaving mice with high signal‐to‐noise ratio. [Image: see text]

Functional probes are a leading contender for the recognition and manipulation of nervous behavior and are characterized by substantial scientific and technological potential. Despite the recent development of functional neural probes, a flexible biocompatible probe unit that allows for long‐term simultaneous stimulation and signaling is still an important task. Here, a category of flexible tiny multimaterial fiber probes (90%), and effectively minimizes the impedance (by up to one order of magnitude) of the probe. This ability allows to realize long‐term (at least 10 weeks) simultaneous optical stimulation and neural recording at the single‐cell level in behaving mice with signal‐to‐noise ratio (SNR = 30 dB) that is more than 6 times that of the benchmark probe such as an all‐polymer fiber., A category of tiny fiber probes with metal electrodes regularly embedded inside the double‐clad biocompatible polymer fiber is realized. This arrangement enables excellent mechanical properties, high transmission (>90%), and low impedance (22.71 MΩ cm2 at 1 kHz), which can realize long‐term simultaneous optical stimulation and neural recording at the single‐cell level in behaving mice with high signal‐to‐noise ratio.

Two old (Huangsedadou and Longxixiaohuangpi (LX)) and two new (Jindou 19 (JD) and Zhonghuang 30 (ZH)) soya bean (Glycine max (L.) Merr.) cultivars were used to investigate the influence of soil drying on the abscisic acid (ABA) accumulation in leaves, stomatal conductance (gs), leaf water relations, osmotic adjustment (OA), leaf desiccation tolerance, yield and yield components. The greater ABA accumulation was induced by soil drying, which also inducing gs decreased at higher soil water contents (SWC) and leaf relative water content (RWC) significantly decreased at lower SWC in the new soya bean cultivars than in the old soya bean cultivars. The soil water threshold between the value at which stomata began to close and the RWC began to decrease was significantly broader in the new cultivars than in the old cultivars. The new cultivars had significantly higher OA and lower lethal leaf water potential than old cultivars when the soil dried. The old cultivars had greater biomass, but lower grain yield than the new cultivars in well-watered, moderate stress and severe stress conditions. Thus with soil drying, the new soya bean cultivars demonstrated greater adaptation to drought by inducing greater ABA accumulation, stomatal closure at higher SWC, enhanced OA and better water relations, associated with increased leaf desiccation tolerance, greater water use efficiency and higher yield.

The preference of phytoplankton for ammonium over nitrate has traditionally been explained by the greater metabolic cost of reducing oxidized forms of nitrogen. This "metabolic cost hypothesis" implies that there should be a growth disadvantage on nitrate compared to ammonium or other forms of reduced nitrogen such as urea, especially when light limits growth, but in a variety of phytoplankton taxa, this predicted difference has not been observed. Our experiments with three strains of marine Synechococcus (WH7803, WH7805, and WH8112) did not reveal consistently faster growth (cell division) on ammonium or urea as compared to nitrate. Urease and glutamine synthetase (GS) activities varied with nitrogen source in a manner consistent with regulation by cellular nitrogen status via NtcA (rather than by external availability of nitrogen) in all three strains and indicated that each strain experienced some degree of nitrogen insufficiency during growth on nitrate. At light intensities that strongly limited growth, the composition (carbon, nitrogen, and pigment quotas) of WH7805 cells using nitrate was indistinguishable from that of cells using ammonium, but at saturating light intensities, cellular carbon, nitrogen, and pigment quotas were significantly lower in cells using nitrate than ammonium. These and similar results from other phytoplankton taxa suggest that a limitation in some step of nitrate uptake or assimilation, rather than the extra cost of reducing nitrate per se, may be the cause of differences in growth and physiology between cells using nitrate and ammonium.

Background Apelin is a peptide ligand of the G-protein-coupled receptor APJ and exhibits anti-diabetes and anti-heart failure activities. However, short serum half-life of the apelin peptide limits its potential clinical applications. This study aimed to develop a long-acting apelin analog. Methods To extend apelin's in vivo half-life, we made a recombinant protein by fusing the IgG Fc fragment to apelin-13 (Fc-apelin-13), conducted pharmacokinetics studies in mice, and determined in vitro biological activities in suppressing cyclic adenosine monophosphate and activating extracellular signal-regulated kinase signalling by reporter assays. We investigated the effects of Fc-apelin-13 on food intake, body weight, fasting blood glucose and insulin levels, glucose tolerance test, hepatic steatosis, and cardiac function and fibrosis by subcutaneous administration of Fc-apelin-13 in diet-induced obese mice for 4 weeks. Results The estimated half-life of Fc-apelin-13 in blood was approximately 33 hours. Reporter assays showed that Fc-apelin-13 was active in suppressing cyclic adenosine monophosphate response element and activating serum response element activities. Four weeks of Fc-apelin-13 treatment in obese mice did not affect food intake and body weight, but resulted in a significant improvement of glucose tolerance, and a decrease in hepatic steatosis and fibrosis, as well as in serum alanine transaminase levels. Moreover, cardiac stroke volume and output were increased and cardiac fibrosis was decreased in the treated mice. Conclusions Fc-apelin-13 fusion protein has an extended in vivo half-life and exerts multiple benefits on obese mice with respect to the improvement of glucose disposal, amelioration of liver steatosis and heart fibrosis, and increase of cardiac output. Hence, Fc-apelin-13 is potentially a therapeutic for obesity-associated disease conditions.