Physiology and transcriptomics highlight the underlying mechanism of sunflower responses to drought stress and rehydration.

Drought can adversely influence the crop growth and production. Accordingly, sunflowers have strong adaptability to drought; hence, we conducted analyses for sunflower seedlings with drought stress and rehydration drought acclimation through physiological measurements and transcriptomics. It showed that drought can cause the accumulation of ROS and enhance the activity of antioxidant enzymes and the content of osmolytes. After rehydration, the contents of ROS and MDA were significantly reduced concomitant with increased antioxidant activity and osmotic adjustment. Totally, 2,589 DEGs were identified among treatments. Functional enrichment analysis showed that DEGs were mainly involved in plant hormone signal transduction, MAPK signaling, and biosynthesis of secondary metabolites. Comparison between differentially spliced genes and DEGs indicated that bHLH025, NAC53, and SINAT3 may be pivotal genes involved in sunflower drought resistance. Our results not only highlight the underlying mechanism of drought stress and rehydration in sunflower but also provide a theoretical basis for crop genetic breeding.

Study on the interaction of Zea mays L. centrin and melittin.

Zea mays L. centrin (Zmcen) is a 20 kDa calcium binding protein also known as caltractin. We used melittin as a simulated target peptide and examined its interaction with Zmcen to understand the structure of Zmcen and the mechanism of interaction with downstream target peptides. The circular dichroism spectrum was used to characterize the typical α-helix structure of Zmcen, and after combining with melittin, the α-helix content of Zmcen changed. Trp residues in melittin were used as fluorescent probes to monitor changes in the conformation of Zmcen upon melittin binding. The Trp residues in melittin gradually shifted from polar environments to nonpolar environments, fluorescence peaks were significantly blueshifted, and the intensity of the fluorescence peak increased. These results showed that Zmcen and melittin combined in a 1 : 1 ratio to form a new complex. The influence of metal ions on binding was also investigated. The combination of Ca2+ and Zmcen helped expose more hydrophobic regions of Zmcen and promoted the binding of Zmcen and melittin. In addition, 2-p-toluidinylnaphthalene-6-sulfonate (TNS) was used as a hydrophobic probe to bind to Zmcen and Zmcen occupied the hydrophobic area on the surface of Zmcen, thereby weakening the binding of Zmcen and melittin. The Biacore experiment was used to calculate the equilibrium constant (K D) for the dissociation of Zmcen and melittin. Melittin mainly binds to C-Zmcen but not to N-Zmcen, indicating that the binding site of melittin on Zmcen was mainly at the C-terminus of Zmcen.

Diversity patterns of soil microbial communities in the Sophora flavescens rhizosphere in response to continuous monocropping.

BACKGROUND: Continuous monocropping can affect the physicochemical and biological characteristics of cultivated soil. Sophora flavescens is a valuable herbal medicine and sensitive to continuous monocropping. Currently, diversity patterns of soil microbial communities in soil continuous monocropping with S. flavescens have not been extensively elucidated. RESULTS: In this study, comparative 16S rDNA and internal transcribed spacer (ITS) MiSeq sequencing analyses were used to examine the taxonomic community structure and microbial diversity in nonrhizosphere soil (CK) and rhizosphere soils (SCC, TCC, and FCC) sampled from fields that had undergone two, three, and five years of continuous monocropping, respectively. Among the microbial communities, a decreased abundance of Acidobacteria and increased abundances of Proteobacteria and Bacteroidetes were found with the increase in monocropping years of S. flavescens. As the continuous monocropping time increased, the diversity of the bacterial community decreased, but that of fungi increased. Redundancy analysis also showed that among the properties of the rhizosphere soil, the available phosphorus, organic matter, total nitrogen, and sucrase had the greatest impacts on the diversity of the rhizosphere microbial community. Moreover, a biomarker for S. flavescens soil was also identified using the most differentially abundant bacteria and fungi in soil samples. CONCLUSIONS: Our study indicates that long-term monocropping exerted great impacts on microbial community distributions and soil physicochemical properties. The relationship between microbial community and physicochemical properties of rhizosphere soil would help clarify the side effects of continuous S. flavescens monocropping. Our study may aid in uncovering the theoretical basis underlying obstacles to continuous monocropping and provide better guidance for crop production.

Crystal structure of 4-meth-oxy-N-phenyl-benzamide.

In the title mol-ecule, C14H13NO2, the dihedral angle between the planes of the benzene rings is 65.18 (4)°. The central amide group has about the same degree of twist with respect to both ring planes, as indicated by the dihedral angles of 34.70 (8) and 30.62 (8)° between its plane and that of the phenyl and 4-meth-oxy-benzene rings, respectively. The C atom of the meth-oxy group is close to being coplanar with its attached ring [deviation = -0.112 (2) Å]. In the crystal, mol-ecules are linked by inter-amide N-H⋯O hydrogen bonds, which generate C(4) chains propagating in the [100] direction. Adajcent mol-ecules in the chain are related by translational symmetry.

Combined use of NGF/BDNF/bFGF promotes proliferation and differentiation of neural stem cells in vitro.

Neurotrophic factors can promote the proliferation and differentiation of neural stem cells (NSCs). Here we report that the possibility of using bFGF in combination with BDNF and NGF to promote proliferation and differentiation of NSCs in vitro. C57BL/6 mouse NSCs were cultured, passaged and stained by immunofluorescence for nestin and GFP. According to different neurotrophic factors added to NSCs, seven experiment groups (NGF, BDNF, bFGF, bFGF+NGF, bFGF+BDNF, NGF+BDNF and NGF+BDNF+bFGF) and a blank control group were established. One week after induction and differentiation, results showed that there was significant difference in the percentage of NSCs differentiating into neurons among the experiment groups. The percentage in the multi-factor groups was significantly higher than that in the single-factor groups (p<0.05), among which the percentage was the highest in NGF+BDNF+bFGF group. In the two-factor groups, the percentage in bFGF+NGF and bFGF+BDNF groups was significantly higher than that in NGF+BDNF group (p<0.05). The NSCs growth curves showed that cells proliferated continuously with the time of culture prolonging, but there was significant difference between the group containing bFGF and that without bFGF. Our results demonstrate that combined use of NGF/BDNF/bFGF significantly improved the ability of NSCs proliferation and differentiation.

A facile channel for D-glucose detection in aqueous solution.

Three facile ensembles for sensing D-glucose are designed and constructed. The ensembles are comprised of fluorescent dye (NAHBDS) and boronic acid substituted viologens (BBVs) quenchers/receptors. The sensing processes of three ensembles (NAHBDS/o-BBV, NAHBDS/m-BBV and NAHBDS/p-BBV) to D-glucose were determined by fluorescence spectra at pH 7.4 buffer solution. The results show that NAHBDS/o-BBV and NAHBDS/m-BBV ensembles embody higher sensitivity for D-glucose with reversible "on-off" fluorescence response. More importantly, the recovery of relative intensity has good linear relation to low concentration of D-glucose. The action between the ensemble with D-glucose is dynamically reversible equilibrium process. The research results provide a new mode to design highly selective probe.

Highly selective ensembles for D-fructose based on fluorescent method in aqueous solution.

Three highly sensitive and selective switches for monosaccharides were composed by anionic polyelectrolyte PPPSO(3)Na and cationic viologen quencheres BBVs. The sensing processes of three ensembles (PPPSO(3)Na/o-BBV, PPPSO(3)Na/m-BBV and PPPSO(3)Na/p-BBV) to common seven monosaccharides have been determined by fluorescence spectra at pH 7.4 buffer solution. The results show that the three sensing ensembles all embody higher selectivity and sensitivity for d-fructose with reversible "on-off-on" fluorescence response. The research results can provide a new mode for developing highly selective probes.