A novel integrated non-targeted metabolomic analysis reveals significant metabolite variations between different lettuce (Lactuca sativa. L) varieties

Lettuce is an important leafy vegetable that represents a significant dietary source of antioxidants and bioactive compounds.However,the levels of metabolites in different lettuce cultivars are poorly characterized.In this study,we used combined GC×GC-TOF/MS and UPLC-IMS-QTOF/MS to detect and relatively quantify metabolites in 30 lettuce cultivars representing large genetic diversity.Comparison with online databases,the published literature,standards as well using collision cross-section values enabled putative identification of 171 metabolites.Sixteen of these 171 metabolites(including phenolic acid derivatives,glycosylated flavonoids,and one iridoid)were present at significantly different levels in leaf and head type lettuces,which suggested the significant metabolomic variations between the leaf and head types of lettuce are related to secondary metabolism.A combination of the results and metabolic network analysis techniques suggested that leaf and head type lettuces contain not only different levels of metabolites but also have significant variations in the corresponding associated metabolic networks.The novel lettuce metabolite library and novel non-targeted metabolomics strategy devised in this study could be used to further characterize metabolic variations between lettuce cultivars or other plants.Moreover,the findings of this study provide important insight into metabolic adaptations due to natural and human selection,which could stimulate further research to potentially improve lettuce quality,yield,and nutritional value.

Supercritical Antisolvent-based Technology for Preparation of Vitamin D3 Proliposome and Its Characteristics

Vitamin D3 （VD3） proliposomes （VDP）, consisted of hydrogenated phosphatidycholine （HPC） and VD3, were prepared using supercritical anti-solvent technology （SAS）. The effects of operation conditions （temperature, pressure and components） on the VD3 loading in VDP were studied. At the optimum conditions of pressure of 8.0 MPa, temperature of 45 ℃, and the mass ratio of 15.0% between VD3 and HPC, the VD3 loading reached 12.89%. VD3 liposomes （VDL） were obtained by hydrating VDP and the entrapment efficiency of VD3 in VDL reached 98.5%. The morphology and structure of VDP and VDL were characterized by SEM （scanning electron micro-scope）, TEM （transmission electron microscope） and XRD （X-ray diffractometer）. The structure of VD3 nanoparti-cles in HPC matrix was formed. The size of VDL with an average diameter of about 1μm was determined by dynamic light scattering instrument （DLS）. The results indicated that VDP can be made by SAS and VDL with high entrapment efficiency can be formed easily via the hydration of VDP.

Metabolic Response of Pakchoi Leaves to Amino Acid Nitrogen

Different nitrogen （N） forms may cause changes in the metabolic profiles of plants. However, few studies have been conducted on the effects of amino acid-N on plant metabolic profiles. The main objective of this study was to identify primary metabolites associated with amino acid-N （Gly, Gln and Ala） through metabolic profile analysis using gas chromatography- mass spectrometry （GC-MS）. Plants of pakchoi （Brassica campestris L. ssp. chinensis L.）, Huawang and Wuyueman cultivars, were grown with different nitrogen forms （i.e., Gly, Gln, Ala, NO3-N, and N starvation） applied under sterile hydroponic conditions. The fresh weight and plant N accumulation of Huawang were greater than those of Wuyueman, which indicates that the former exhibited better N-use efficiency than the latter. The physiological performances of the applied N forms were generally in the order of NO3-N〉Gln〉Gly〉Ala. The metabolic analysis of leaf polar extracts revealed 30 amino acid N-responsive metabolites in the two pakchoi cultivars, mainly consisting of sugars, amino acids, and organic acids. Changes in the carbon metabolism of pakchoi leaves under amino acid treatments occurred via the accumulation of fructose, glucose, xylose, and arabinose. Disruption of amino acid metabolism resulted in accumulation of endogenous Gly in Gly treatment, Pro in Ala treatment, and Asn in three amino acid （Gly, Gln and Ala） treatments. By contrast, the levels of endogenous Gln and Leu decreased. However, this reduction varied among cultivars and amino acid types. Amino acid-N supply also affected the citric acid cycle, namely, the second stage of respiration, where leaves in Gly, Gln and Ala treatments contained low levels of malic, citric and succinic acids compared with leaves in NO3-N treatments. No significant difference in the metabolic responses was observed between the two cultivars which differed in their capability to use N. The response of primary metabolites in pakchoi leaves to amino acid-N supply may serve an important function in pakchoi adaptation to amino acid-N sources.

Nucleation and growth of high purity aluminum grains in directional solidification bulk sample without electromagnetic stirring

A self-made directional solidification device was used to fabricate d 80 mm high purity aluminum ingots. SEM and AFM were used to detect the shape of grain boundaries. The orientation of the grain was studied by X-ray diffractometry. The results show that the nucleation points locate at the intersections of three adjacent grains. The lattice orientation of grains does not alter in the horizontal direction, but gradually approaches the optimum growth direction in the vertical direction during the growth process. All the grains suffer the competition and only the one whose orientation is closest to the preferred direction can occupy the final growth space.

Production of Submicroparticles of β-Sitosterol Using an Aerosol Solvent Extraction System

The submicroparticles of β-sitosterol were produced by using an aerosol solvent extraction system （ASES） and characterized by scanning electronic microscope （SEM）, X-ray diffraction （XRD）, and Fourier transform infrared （FT-IR） analysis. The effects of operational parameters including pressure, temperature, solution concentration, and ratio of flow rate （CO2/solution, r） on particle size （PS）, yield, and morphology were investigated. The results showed that microparticles of β-sitosterol （less than 1000 nm size and larger than 70% yield） could be obtained at 10-15 MPa, 35 50℃, 15 mg·ml^-1, 10/1（r）; β-sitosterol particles were found to occur as three mophologies： flakes, rods, and spheres by varying ratio of flow rate or solution concentration. In contrast, the crystallinity of β-sitosterol decreased, whereas its molecular structure remained almost unchanged after being ASES-treated. Therefore, ASES was an effective method to produce submicroparticles of β-sitosterol.

Influence of multilayer coatings on AZ31 deposited by electron beam evaporation

Three different coatings, Cr, SiO2/Cr and HfO2/SiO2 were deposited by electron beam physical vapor deposition (EB-PVD). Relevant composition and mechanical properties were obtained. The results show that the surface mechanical property could be increased, and Cr coating sample possessed the highest microhardness. Cyclic oxidation in air at 773 K was applied to evaluate the oxidation resistance of the coatings, and the section morphologies of the coatings were observed by FEISEM. The results indicate that the oxidation rate of AZ31 with Cr, SiO2/Cr and HfO2/SiO2 coatings is decreased, and the SiO2/Cr coating sample exhibits the best oxidation resistance and keeps relatively good adhesion up to 96 h. Polarization results prove that the corrosion resistance of AZ31 can be improved and the SiO2/Cr coating sample has the best property.

The Edge Magnetization and Strip Phase of Graphene Quantum Dots with Long-Range Coulomb Interaction

We investigate the magnetism and optical absorption properties of charge neutral hexagonal graphene quantum dots （GODs） terminated with zigzag edges by using a tight-binding Hubbard type model for the 7r electrons. Within the Hartree Fock approximation and taking into account the long-range Coulomb interaction, our cal- culation yields a ferromagnetic ground state with magnetic moments localized on the edges for GODs, and also gives an antiferromagnetism state with the energy very c/ose to the ferromagnetism ground state. We find that both the ferromagnetic and the antiferrornagnetic states have stripe patterned charge density distributions as a result of the long-range Coulomb interaction. The optical conductivity for GQDs has an energy gap in the low frequency regime in contrast to the bulk neutral graphene sheet where a universal constant is approached.

东亚地区栓皮栎叶片表皮毛空间变异特征及其与气孔的协同关系

理解植物功能性状的地理变异对预测全球气候变化下的植物响应至关重要。叶片表皮毛由表皮细胞发育而来,具有调节叶片温度和控制气体交换的功能,然而大的地理尺度上叶片表皮毛如何变异,以及它们与气孔之间的关系仍不清楚。本研究以栓皮栎(Quercus variabilis)为研究对象,分析了东亚地区44个种群叶片表皮毛密度,并评估了它们与气候因子和气孔等性状之间的相关性。同时,为了进一步检测环境变化下的表皮毛响应特征以及与气孔之间的协同关系,本研究利用其中15个种群开展了同质园试验。研究结果发现,栓皮栎叶片表皮毛密度平均值为459.78个mm^(−2),变异范围为325.79–552.38 mm^(−2)。表皮毛密度会随纬度增加而增加,随经度减少而减少,并且与温度和降水呈负相关。同时发现,无论是在野外还是在同质园,叶片表皮毛密度均与气孔密度呈正相关,并且两者均会随干旱强度的增加而增加。这些结果表明,面对环境变化叶片表皮毛密度具有高度的适应性变异,并且可与气孔协同适应这种变化。该研究结果对加深理解气候变化下植物适应策略以及叶片功能性状之间的协同互作具有重要意义。

Specific pupylation as IDEntity reporter(SPIDER)for the identification of protein-biomolecule interactions

Protein-biomolecule interactions play pivotal roles in almost all biological processes.For a biomolecule of interest,the identification of the interacting protein(s)is essential.For this need,although many assays are available,highly robust and reliable methods are always desired.By combining a substrate-based proximity labeling activity from the pupylation pathway of Mycobacterium tuberculosis and the streptavidin(SA)-biotin system,we developed the Specific Pupylation as IDEntity Reporter(SPIDER)method for identifying protein-biomolecule interactions.Using SPIDER,we validated the interactions between the known binding proteins of protein,DNA,RNA,and small molecule.We successfully applied SPIDER to construct the global protein interactome for m^(6)A and m RNA,identified a variety of uncharacterized m^(6)A binding proteins,and validated SRSF7 as a potential m^(6)A reader.We globally identified the binding proteins for lenalidomide and Cob B.Moreover,we identified SARS-CoV-2-specific receptors on the cell membrane.Overall,SPIDER is powerful and highly accessible for the study of proteinbiomolecule interactions.

Tapetum Degeneration Retardation is Critical for Aliphatic Metabolism and Gene Regulation during Rice Pollen Development

As a complex wall system in flowering plants, the pollen outer wall mainly contains aliphatic sporopollenin; however, the mechanism for synthesizing these lipidic precursors during pollen development remains less well understood. Here, we report on the function of the rice tapetum-expressing TDR （Tapetum Degeneration Retardation） gene in aliphatic metabolism and its regulatory role during rice pollen development. The observations of transmission electron microscopy （TEM） and scanning electron microscopy （SEM） analyses suggested that pollen wall formation was significantly altered in the tdr mutant. The contents of aliphatic compositions of anther were greatly changed in the tdr mutant revealed by GC-MS （gas chromatography-mass spectrometry） testing, particularly less accumulated in fatty acids, primary alcohols, alkanes and alkenes, and an abnormal increase in secondary alcohols with carbon lengths from C29 to C3S in tdr. Microarray data revealed that a group of genes putatively involved in lipid transport and metabolism were significantly altered in the tdr mutant, indicating the critical role of TDR in the formation of the pollen wall. Also, a wide range of genes （236 in total--154 up-regulated and 82 down-regulated） exhibited statistically significant expressional differences between wild-type and tdr. In addition to its function in promoting tapetum PCD, TDR possibly plays crucial regulatory roles in several basic biological processes during rice pollen development.

Using 2D NMR to determine the degree of branching of complicated hyperbranched polymers

Degree of branching (DB) is a crucial structure parameter of hyperbranched polymers, which can be determined by 1H NMR, quantitative 13C NMR, degradative method, etc. However, for complicated hy-perbranched polymers, intricate structure and severe overlap of spectral signals hinder the determina-tion of DB using traditional methods. In this work, the architecture of complicated hyperbranched polymers has been elucidated with the help of 2D NMR techniques. Using such a method, overlapped NMR signals can be well separated into a two-dimensional space, and additional structural information is also available. Correspondingly, quantitative analysis for complicated systems can be realized. De-termination of DBs for three types of complicated hyperbranched polymers synthesized from step-polymerization, self-condensation vinyl polymerization and self-condensation ring-opening po-lymerization is shown as examples.

Generation of trans-arachidonic acid under nitrative stress is associated with upregulation of thromponsdin-1 in diabetic rats

Background Trans-arachidonic acids （TAAs）, newly discovered markers of nitrative stress and the major products of nitrogen dioxide （NO2）-mediated isomerization of arachidonic acid （AA）, represent a new mechanism of NO2-induced toxicity. It has been reported that TAAs were generated in oxygen-induced microvascular degeneration model and TAAs were also generated in a diabetic retinopathy （DR） model. In this study, we examined high glucose-induced nitrative stress damage and TAAs levels and explored the possible mechanisms for DR caused by reactive nitrogen species. Methods Diabetic rats were induced by intraperitoneal injection of streptozotocin （BTZ） at 60 mg/kg. Bovine retinal capillary endothelial cells （BRECs） were selectively cultured and incubated with normal or high glucose. The serum TAAs and AA in diabetic rats were measured by the gas chromatography and mass spectrometry （GC/MS） method. The ratio of peak area of TAAs to AA with selected ion of 79 was estimated by a group t-test. Thrombospondin-1 （TSP-1） in the rat retinas and BRECs extracts were examined by Western blotting. The phosphorylation of extracellular signal-regulated kinase 1/2 （ERK1/2） protein was examined by Western blotting in BRECs incubated with high glucose. Results The TAAs to AA ratio （TAAs/AA） was significantly increased in the serum at 8, 12 and 16 weeks after BTZ injection （P 〈0.05）, with no noticeable change found at 2 or 4 weeks （P 〉0.05）. Expression of TSP-1 in the retina of diabetic rats was progressively elevated according to the duration of diabetes. TSP-1 expression was increased in BRECs incubated with high glucose all 48 hours. Moreover, high glucose also increased ERK1/2 expression, which peaked at 30 minutes and then decreased in the following 48 hours. Conclusion An elevation of TAAs/AA is associated with high glucose-induced nitrative stress, which probably involves upregulation of TSP-1 through activating ERK1/2.

Aggregation-induced Emission of Non-conjugated Poly(amido amine)s:Discovering,Luminescent Mechanism Understanding and Bioapplication

It is found that the fluorescence of aliphatic poly（amido amine）s including linear and hyperbranched ones can be dramatically enhanced by simple aggregation of polymer chains, attributing to the formation of a variety of intra- and interchain clusters with shared lone-pair electrons and the restriction of intramolecular motions. Thanks to the combination of strong solid fluorescence and excellent biocompatibility, these non-conjugated polymers become promising candidates for bioimaging such as bacterial detection. This finding not only extends the aggregation-induced emission（AIE） systems from conjugated compounds to non-conjugated materials, which expands the bioapplication range of AIE systems, but also sheds light on the exploration of novel unconventional luminogens.

Facile Preparation of Water-Soluble and Cytocompatible Small-Sized Chitosan-Polydopamine Nanoparticles

In this paper, a kind of novel water-soluble chitosan-polydopamine （CHT-PDA） nanoparticles with a hydrody- namic diameter （Dh） around 10 nm were reported by the combination of self-polymerization of PDA and electro- static complexation between PDA and CHT in water/DMSO （W/D） mixture at the molar fraction of DMSO （XDMSO =0.37）. The preparation method was efficient with a yield of 98% around. The as-prepared water-soluble CHT-PDA nanoparticles exhibited effective UV-screen ability, enhanced visible-light transmittance and good cyto- compatibility via MTT assay, which might be used in transparent formulation for UV protection usage, especially in biological field including sun care application.

Fabrication of porous scaffolds with protein nanogels

A novel type of porous scaffold was fabricated from single protein nanogels. The nanogels with single protein as core and crosslinked polymer network as shell were prepared through a two-step procedure including surface acryloylation and in situ radical polymerization. The formation of single protein nanogels was verified by matrix assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometer, transmission electron microscopy (TEM) and dynamic light scattering (DLS) analyses. Subsequently, the porous scaffolds were fabricated through a solvent evaporating process of aqueous nanogel solutions. The porous scaffolds were characterized by Fourier transform infrared (FTIR), scanning electronic microscopy (SEM), atomic force microscopy (AFM), and fluorescence microscopy. Interestingly, the obtained porous nanogel scaffolds presented multi-level porous morphologies with macro and nano scale pores, providing better spaces and microenvironments than normal macro porous scaffolds. Cell proliferation assay of nanogels showed low cytotoxicity. Considering that both the protein species and polymer constitutes can be pre-designed and adjusted, these multi-level porous nanogel scaffolds are promising candidates for tissue culture applications.

Tracing drug release process with dual-modal hyperbranched polymer-gold nanoparticle complexes

Dual-modal surface enhanced Raman spectrum(SERS)-fluorescence polymer/metal hybrid complexes have been prepared for tracing drug release process in tumor cells. Firstly, the hyperbranched poly((S-(4-vinyl) benzyl S′-propyltrithiocarbonate)-co-(poly(ethylene glycol) methacrylate))(HPVBEG) was synthesized via the combination of reversible addition-fragmentation chain-transfer(RAFT) polymerization and self-condensing vinyl polymerization(SCVP). Subsequently, the anticancer drug doxorubicin(DOX) was linked to HPVBEG via pH sensitive Schiff base bonds to form HPVBEG-g-DOX conjugates.Through aminolysis reaction, HPVBEG-g-DOX was coordinated with gold nanoparticles(GNP), resulting in the formation of HPVBEG-g-DOX/GNP complexes. In neutral condition, the HPVBEG-g-DOX/GNP complexes were stable, and DOX was bound to the surface of GNPs. Therefore, the SERS of DOX could be observed, while the fluorescence of DOX was quenched by GNPs. Under an acidic environment, DOX was released from the surface of GNPs with breakage of Schiff base bonds.Thus, the SERS signal of DOX was gradually reduced. Correspondingly, the fluorescence signal of DOX was enhanced.Through dual-modal SERS-fluorescence technique, the DOX delivery and release process was traced in tumor cells. Moreover,the viability of MCF-7 cells incubated with HPVBEG-g-DOX/GNP complexes was investigated by Cell Counting Kit-8(CCK-8) assay. The experimental results showed that HPVBEG-g-DOX/GNP complexes had similar proliferation inhibition effect compared with free DOX. Definitely, the dual-modal SERS-fluorescence complexes for tracing drug delivery and release will have promising prospects on tumor diagnosis and therapy.

Tunable construction of transition metal-coordinated helicene cages

We report a facile and tailored method to prepare globally twisted chiral molecular cages through tunable coordination of bis-bipyridine-terminated helicene ligands to a series of transition metals including Fe(Ⅱ), Co(Ⅱ), Ni(Ⅱ) and Zn(Ⅱ). This system shows an efficient remote transfer of stereogenecity from the helicene core to the bipyridine-metal coordination sites and subsequently the entire cages. While the Fe(Ⅱ), Co(Ⅱ) and Ni(Ⅱ)-derived M_(2)L_(3)(M for metal and L for ligand) cages exhibit quasi-reversible redox features, the Zn(Ⅱ) analogues reveal prominent yellow circularly polarized luminescence. Interestingly,with the addition of Na_(2)SO_(4), the Zn_(2)L_(3)cages reassemble into sextuple-stranded Zn_(6)L_(6)(SO_(4))_(4)cages in which three Zn_(2)L_(2) units are bound together by four sulfates and further coalesced by offset inter-ligandπ-π interactions.

Bioinspired Activation of N_(2) on Asymmetrical Coordinated Fe Grafted 1T MoS_(2) at Room Temperature

Main observation and conclusion Inspired by the nitrogen fixation process on MoFe nitrogenase,asymmetrical coordinated Fe grafted onto 1T MoS_(2) were successfully synthesized.The unique electron-rich structure with asymmetrical coordination made the 1T Fe_(0.1)Mo_(0.9)S_(2) layered material actively react with water and dinitrogen at room temperature and atmosphere pressure.

Effect of Branching Architecture on Glass Transition Behavior of Hyperbranched Copolystyrenes:the Experiment and Simulation Studies

By controlling the feed ratio of CMS/styrene and the polymerization time, a series of hyperbranched copolystyrenes（HBCPS） were synthesized with comparable weight-averaged molecular weights（Mw） but different degree of branching（DB） through atom transfer radical self-condensing vinyl copolymerization（ATR-SCVCP） with Cu Br/2,2？-bipyridyl as the catalyst. The resulting HBCPS samples were used to investigate the effect of branching architecture on their glass transition behavior. With the DB increased, the glass transition temperatures（Tg） of HBCPS samples measured by DMA and DSC both decreased. Their spin-lattice relaxation times（1H T1r） of protons displayed the same downtrend with increasing DB. Besides, a correlation between the Tgs and the DB was well established by all-atom molecular dynamics（MD） simulations. The values of MD-determined Tgs are little higher than the corresponding experimental ones. However, the dependence of Tgs on DB is in good agreement with the experimental results, i.e., Tg decreases both in experiments and simulations with increasing DB.