Genome-Wide Identification of MADS-Box Genes in Taraxacum kok-saghyz and Taraxacum mongolicum: Evolutionary Mechanisms, Conserved Functions and New Functions Related to Natural Rubber Yield Formation.

MADS-box transcription regulators play important roles in plant growth and development. However, very few MADS-box genes have been isolated in the genus Taraxacum, which consists of more than 3000 species. To explore their functions in the promising natural rubber (NR)-producing plant Taraxacum kok-saghyz (TKS), MADS-box genes were identified in the genome of TKS and the related species Taraxacum mongolicum (TM; non-NR-producing) via genome-wide screening. In total, 66 TkMADSs and 59 TmMADSs were identified in the TKS and TM genomes, respectively. From diploid TKS to triploid TM, the total number of MADS-box genes did not increase, but expansion occurred in specific subfamilies. Between the two genomes, a total of 11 duplications, which promoted the expansion of MADS-box genes, were identified in the two species. TkMADS and TmMADS were highly conserved, and showed good collinearity. Furthermore, most TkMADS genes exhibiting tissue-specific expression patterns, especially genes associated with the ABCDE model, were preferentially expressed in the flowers, suggesting their conserved and dominant functions in flower development in TKS. Moreover, by comparing the transcriptomes of different TKS lines, we identified 25 TkMADSs related to biomass formation and 4 TkMADSs related to NR content, which represented new targets for improving the NR yield of TKS.

Controlling the shape morphology of origami-inspired photoresponsive hydrogels.

The concept of origami has influenced the development of responsive materials that can mimic complex functions performed by living organisms. An ultimate goal is to discover and design soft materials that can be remotely actuated into diverse structures. To achieve this goal, we design and synthesize here a light-responsive spiropyran hydrogel system that can display dynamic shape changes upon irradiation with local light. We use a continuum polymer model to analyze the behavior of the constructed photoactive hydrogel, which is in good agreement with the experimental results. We explore different buckling modalities and patterns in a different range of parameters. The synthesis and fabrication of these materials demonstrate that the theoretical model can be used to drive the development of responsive photoactive systems.

Supramolecular-covalent hybrid polymers for light-activated mechanical actuation.

The development of synthetic structures that mimic mechanical actuation in living matter such as autonomous translation and shape changes remains a grand challenge for materials science. In living systems the integration of supramolecular structures and covalent polymers contributes to the responsive behaviour of membranes, muscles and tendons, among others. Here we describe hybrid light-responsive soft materials composed of peptide amphiphile supramolecular polymers chemically bonded to spiropyran-based networks that expel water in response to visible light. The supramolecular polymers form a reversibly deformable and water-draining skeleton that mechanically reinforces the hybrid and can also be aligned by printing methods. The noncovalent skeleton embedded in the network thus enables faster bending and flattening actuation of objects, as well as longer steps during the light-driven crawling motion of macroscopic films. Our work suggests that hybrid bonding polymers, which integrate supramolecular assemblies and covalent networks, offer strategies for the bottom-up design of soft matter that mimics living organisms.

Structures of a glucose-tolerant ß-glucosidase provide insights into its mechanism.

Cellulose can be converted to ethanol via the fermentation of glucose, which is considered as a promising green alternative for transportation fuels. The conversion of cellulose to glucose needs three enzymes, in which ß-glucosidase (BGL) plays an essential role. However, BGL is inhibited by its own product glucose, greatly limiting its applications in industry. We previously obtained a novel BGL named Bgl6 with a high glucose tolerance. Further engineering through random mutagenesis produced a triple mutant M3 with improved thermostability. This enzyme shows promising properties for wide applications but the structural basis of the unusual properties of Bgl6 is not clear. In this study, we determined the crystal structures of Bgl6 and variants at high resolution, which provide insights into its glucose-tolerant mechanism and thermostability. Particularly, Bgl6 forms an extra channel that could be used as a secondary binding site for glucose, which may contribute to glucose tolerance. Additionally, the triple mutations could strengthen the hydrophobic interactions within the enzyme and may be responsible for the enhanced thermostability exhibited by M3, which was further confirmed by dynamic light scattering data. Lastly, structural comparison to other orthologs allows us to formulate new strategies on how to improve the catalytic efficiency of Bgl6.

Rapid formation of a supramolecular polypeptide-DNA hydrogel for in†situ three-dimensional multilayer bioprinting.

A rapidly formed supramolecular polypeptide-DNA hydrogel was prepared and used for in situ multilayer three-dimensional bioprinting for the first time. By alternative deposition of two complementary bio-inks, designed structures can be printed. Based on their healing properties and high mechanical strengths, the printed structures are geometrically uniform without boundaries and can keep their shapes up to the millimeter scale without collapse. 3D cell printing was demonstrated to fabricate live-cell-containing structures with normal cellular functions. Together with the unique properties of biocompatibility, permeability, and biodegradability, the hydrogel becomes an ideal biomaterial for 3D bioprinting to produce designable 3D constructs for applications in tissue engineering.

Investigation on the Effectiveness of Digital Scanning Combined with Reverse Engineering Technology in Demonstrating Full Crown Tooth Preparation.

OBJECTIVE: To investigate the effect of digital scanning combined with reverse engineering technology in the demonstration of full crown tooth preparation. METHODS: Thirty-one students were randomly divided into the two groups. The students in the control group carried out traditional demonstration by the use of eye-measurement methods. The students in the experimental group carried out improved demonstration by the use of digital intraoral scan with 3D measurement data. The students in both groups were provided with two resin teeth to conduct full crown tooth preparation on head model dental simulators. The teeth prepared before and after demonstration were scored by Chinese Stomatological Association Group Standards, with a total score of 100 points. Analysis of covariance was performed to comparatively analyze the scores related to the tooth surfaces, and convergence angle between two groups. RESULTS: Analysis of two prepared teeth (tooth #11 and #16) in two groups showed that there was a statistical significant difference in the mean score between the control group and experimental group (tooth #11, P = 0.0039) (tooth #16, P = 0.0120).The demonstration of the tooth #16 showed that there were statistical significant differences in the scores related to buccolingual surface (P = 0.0205) and proximal surface (P = 0.0023) between the control group and experimental group; There was a statistical significant difference in the score related to the convergence angle of buccolingual surface between the control group and experimental group (P = 0.0265). CONCLUSION: The digital methods can effectively improve the quality of tooth preparations and has a pedagogical advantage for posterior teeth, which present greater operational challenges.

Polydopamine-functionalized electrospun poly(vinyl alcohol)/chitosan nanofibers for the removal and determination of Cu(II).

Environmentally friendly and recycled polydopamine-functionalized electrospun poly(vinyl alcohol)/chitosan nanofibers (PVA/CS/PDA) were prepared through a low-energy-consumption procedure. The PDA coating endows PVA/CS/PDA nanofibers with good water stability. The PVA/CS/PDA nanofibers have a fibrillar and porous structure that is favorable for Cu(II) to access the active sites of the nanofibers. The adsorption isotherm and kinetics data preferably conform to the Liu isotherm and pseudo-second-order kinetic models, respectively. The maximum adsorption capacity of Cu(II) ions by PVA/CS/PDA nanofibers from the Liu isotherm model is 326.5 mg g-1. The PVA/CS/PDA nanofibers exhibit higher adsorption capacity than some other reported adsorbents. The adsorption mechanism study demonstrates that the Cu(II) adsorption is mainly ascribed to the complexation of Cu(II) with the imino, amino, and hydroxy moieties in PVA/CS/PDA nanofibers. The nanofibers can be employed for 5 cycles without significantly deteriorating performance. More interestingly, a fluorometry method based on the oxidation mimic enzyme activity of Cu(II) was developed to detect low concentrations of Cu(II) using the nanofibers as an adsorbent to preconcentrate Cu(II). The limit of detection is 0.42 mg L-1. The successful removal and detection of Cu(II) in Pearl River and mineral water samples demonstrates the great potential of PVA/CS/PDA nanofibers to remediate Cu(II)-polluted water.

Injectable isoniazid-loaded bone cement based on hydrazone bonds achieving long-term release and decent mechanical properties.

A robust and easily manufactured high-strength and long-term release hydrazone-based isoniazid acrylic (HIA) bone cement is reported. The mechanical strength of HIA bone cement is similar to that of normal polymethyl methacrylate (PMMA) bone cement, far surpassing that of traditional isoniazid-containing antibiotic-loaded bone cement (INH bone cement). Isoniazid is connected to the bone cement through bioorthogonal hydrazone chemistry, and it possesses release properties superior to those of INH bone cement, allowing for the sustained release of isoniazid for up to 12 weeks. In vivo and in vitro studies also indicate that HIA cement exhibits better biocompatibility than INH bone cement. The results of this study not only signify progress in the realm of antimicrobial bone cement for addressing bone tuberculosis but also enhance our capacity to create and comprehend high-performing antimicrobial bone cement.

Injectable self-healing chitosan-based POSS-PEG hybrid hydrogel as wound dressing to promote diabetic wound healing.

Promoting the healing of diabetic wounds remains a major challenge in scientific research today. A star-like eight-arm cross-linker octafunctionalized POSS of benzaldehyde-terminated polyethylene glycol (POSS-PEG-CHO) was synthesized, and crosslinked with hydroxypropyltrimethyl ammonium chloride chitosan (HACC) via Schiff base reaction to obtain Chitosan-based POSS-PEG hybrid hydrogels. The designed composite hydrogels exhibited strong mechanical strength, injectability, excellent self-healing efficiency, good cytocompatibility and antibacterial properties. Furthermore, the composite hydrogels could accelerate cells migration and proliferation, as expected by remarkably promoting wound healing in diabetic mice. The wounds treated with the composite hydrogels displayed faster regeneration of epithelial tissue, fewer inflammatory cells, more collagen deposition and higher expression level of VEGF. Therefore, Chitosan-based POSS-PEG hybrid hydrogel has great application potential as a dressing for promoting the healing of diabetic wounds.

Fabrication of eco-friendly calcium crosslinked alginate electrospun nanofibres for rapid and efficient removal of Cu(II).

The preparation of low-cost adsorbents using naturally available biomaterials to realize the efficient removal of Cu(II) is urgently needed. Herein, low-cost and recyclable calcium crosslinked alginate electrospun nanofibres (SA-Ca) were prepared using low-cost materials via a low-energy-consumption process. The prepared SA-Ca possesses a porous network structure, and its average diameter, specific surface area, and tensile strength are approximately 129.6 nm, 3.409 m2 g-1, and 2.73MPa, respectively. The maximum adsorption capacity of SA-Ca for Cu(II) in aqueous solution is 285.5 mg g-1, and the adsorption can be completed in 0.5 h. The adsorption kinetics were well described by the general-order kinetic model, and the adsorption isotherm fitted to the Liu model. The study of the adsorption mechanism suggested that electrostatic attraction, ion exchange, and complexation cooperated to exert effects. More important, SA-Ca can be regenerated using CaCl2/HCl solutions based on the ion-exchange mechanism without destroying the morphology of the nanofibres. Furthermore, a low concentration of Cu(II) (10 mg L-1) and other heavy metal ions [Pb(II) and Cd(II), each 10 mg L-1] were successfully removed from water, demonstrating that economical biocarbohydrate polymer-based nanofibres have great application prospects in the removal of heavy metal ions.

Surface Modification of Decellularized Heart Valve by the POSS-PEG Hybrid Hydrogel to Prepare a Composite Scaffold Material with Anticalcification Potential.

Tissue-engineered heart valves (TEHVs) are the most promising replacement for heart valve transplantation. Decellularized heart valve (DHV) is one of the most common scaffold materials for TEHVs. In actual clinical applications, the most widely used method for treating DHV is cross-linking it with glutaraldehyde, but this method could cause serious problems such as calcification. In this study, we introduced polyhedral oligomeric silsesquioxane (POSS) nanoparticles into a poly(ethylene glycol) (PEG) hydrogel to prepare a POSS-PEG hybrid hydrogel, and then coated them on the surface of DHV to prepare the composite scaffold. The chemical structures, microscopic morphologies, cell compatibilities, blood compatibilities, and anticalcification properties were further investigated. Experimental results showed that the composite scaffold had good blood compatibility and excellent cell compatibility and could promote cell adhesion and proliferation. In vivo and in vitro anticalcification experiments showed that the introduction of POSS nanoparticles could reduce the degree of calcification significantly and the composite scaffold had obvious anticalcification ability. The DHV surface-coated with the POSS-PEG hybrid hydrogel is an alternative scaffold material with anticalcification potential for an artificial heart valve, which provides an idea for the preparation of TEHVs.

Injectable and Degradable PEG Hydrogel with Antibacterial Performance for Promoting Wound Healing.

Injectable and degradable PEG hydrogel was prepared via Michael-type addition between cross-linking monomer 4-arm-PEG-MAL and two cross-linkers of hydrolysis degradable PEG-diester-dithiol and non-degradable PEG-dithiol, and it had a porous structure with the uniform pore size. The biocompatibility assays in vitro indicated that PEG hydrogel had excellent biocompatibility and can be degraded naturally without leading to any negative impact on cells. The results of antibacterial experiments showed that PEG hydrogel can inhibit the growth of bacteria. Furthermore, the Cell Counting Kit-8 (CCK-8) assay, LIVE/DEAD cell staining, and scratch healing experiments proved that PEG hydrogel can promote cell proliferation and migration, which had been further confirmed in in vivo experiments on the rat wound models. All experimental results demonstrated that PEG hydrogel is an injectable antibacterial dressing, which can promote the process of wound healing and has great potential in the field of wound healing.

Anticalcification Potential of POSS-PEG Hybrid Hydrogel as a Scaffold Material for the Development of Synthetic Heart Valve Leaflets.

Calcification of bioprosthetics is a primary challenge in the field of artificial heart valves and a main reason for biological heart valve prostheses failure. Recent advances in nanomaterial science have promoted the development of polymers with advantageous properties that are likely suitable for artificial heart valves. In this work, we developed a nanocomposite polymeric biomaterial POSS-PEG (polyhedral oligomeric silsesquioxane-polyethylene glycol) hybrid hydrogel, which not only has improved mechanical and surface properties but also excellent biocompatibility. The results of atomic force microscopy and in vivo animal experiments indicated that the content of POSS in the PEG matrix plays an important role on the surface and contributes to its biological properties, compared to the decellularized porcine aortic valve scaffold. Additionally, this modification leads to enhanced protection of the hydrogel from thrombosis. Furthermore, the introduction of POSS nanoparticles also gives the hydrogel a better calcification resistance efficacy, which was confirmed through in vitro tests and animal experiments. These findings indicate that POSS-PEG hybrid hydrogel is a potential material for functional heart valve prosthetics, and the use of POSS nanocomposites in artificial valves may offer potential long-term performance and durability advantages.

Fast and programmable locomotion of hydrogel-metal hybrids under light and magnetic fields.

The design of soft matter in which internal fuels or an external energy input can generate locomotion and shape transformations observed in living organisms is a key challenge. Such materials could assist in productive functions that may range from robotics to smart management of chemical reactions and communication with cells. In this context, hydrated matter that can function in aqueous media would be of great interest. Here, we report the design of hydrogels containing a scaffold of high-aspect ratio ferromagnetic nanowires with nematic order dispersed in a polymer network that change shape in response to light and experience torques in rotating magnetic fields. The synergistic response enables fast walking motion of macroscopic objects in water on either flat or inclined surfaces and also guides delivery of cargo through rolling motion and light-driven shape changes. The theoretical description of the response to the external energy input allowed us to program specific trajectories of hydrogel objects that were verified experimentally.

Codelivery for Paclitaxel and Bcl-2 Conversion Gene by PHB-PDMAEMA Amphiphilic Cationic Copolymer for Effective Drug Resistant Cancer Therapy.

Antiapoptotic Bcl-2 protein's upregulated expression is a key reason for drug resistance leading to failure of chemotherapy. In this report, a series of biocompatible amphiphilic cationic poly[(R)-3-hydroxybutyrate] (PHB)-b-poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) copolymer, comprising hydrophobic PHB block and cationic PDMAEMA block, is designed to codeliver hydrophobic chemotherapeutic paclitaxel and Bcl-2 converting gene Nur77/ΔDBD with enhanced stability, due to the micelle formation by hydrophobic PHB segment. This copolymer shows less toxicity but similar gene transfection efficiency to polyethyenimine (25k). More importantly, this codelivery approach by PHB-PDMAEMA leads to increased drug resistant HepG2/Bcl-2 cancer cell death, by increased expression of Nur77 proteins in the Bcl-2 present intracellular mitochondria. This work signifies for the first time that cationic amphiphilic PHB-b-PDMAEMA copolymers can be utilized for the drug and gene codelivery to drug resistant cancer cells with high expression of antiapoptosis Bcl-2 protein and the positive results are encouraging for the further design of codelivery platforms for combating drug resistant cancer cells.

Spatiotemporally Controlled Release of Rho-Inhibiting C3 Toxin from a Protein-DNA Hybrid Hydrogel for Targeted Inhibition of Osteoclast Formation and Activity.

In osteoporosis, bone structure can be improved by the introduction of therapeutic molecules inhibiting bone resorption by osteoclasts. Here, biocompatible hydrogels represent an excellent option for the delivery of pharmacologically active molecules to the bone tissue because of their biodegradability, injectability, and manifold functionalization capacity. The present study reports the preparation of a multifunctional hybrid hydrogel from chemically modified human serum albumin and rationally designed DNA building blocks. The hybrid hydrogel combines advantageous characteristics, including rapid gelation through DNA hybridization under physiological conditions and a self-healing and injectable nature with the possibility of specific loading and spatiotemporally controlled release of active proteins, making it an advanced biomaterial for the local treatment of bone diseases, for example, osteoporosis. The hydrogels are loaded with a recombinant Rho-inhibiting C3 toxin, C2IN-C3lim-G205C. This toxin selectively targets osteoclasts and inhibits Rho-signaling and, thereby, actin-dependent processes in these cells. Application of C2IN-C3lim-G205C toxin-loaded hydrogels effectively reduces osteoclast formation and resorption activity in vitro, as demonstrated by tartrate-resistant acid phosphatase staining and the pit resorption assay. Simultaneously, osteoblast activity, viability, and proliferation are unaffected, thus making C2IN-C3lim-G205C toxin-loaded hybrid hydrogels an attractive pharmacological system for spatial and selective modulation of osteoclast functions to reduce bone resorption.

Separation, concentration and determination of trace chloramphenicol in shrimp from different waters by using polyoxyethylene lauryl ether-salt aqueous two-phase system coupled with high-performance liquid chromatography.

Polyoxyethylene lauryl ether (POELE10)-NaH2PO4 aqueous two-phase extraction system (ATPES) is coupled with HPLC to analyze chloramphenicol (CAP) in aquatic product. Response surface methodology (RSM) was adopted in the multi-factor experiment to determine the optimized conditions. The extraction efficiency of CAP (E%) is up to 99.42% under the optimal conditions, namely, the concentration of NaH2PO4, the concentration of POELE10, pH and temperature were 0.186 g · mL(-1), 0.033 g · mL(-1), 3.8 and 25 °C respectively. The optimal value of enrichment factor of CAP (F) was 22.56 when the concentration of NaH2PO4 was 0.192 g · mL(-1), the concentration of POELE10 was 0.024 g/ml, pH was 4.2 and temperature was 30 °C. The limit of detection (LOD) and limit of quantification (LOQ) of this method are 0.8 µg · kg(-1) and 1 µg · kg(-1), which meet the needs of determining trace or ultratrace CAP in food. The E% and F of this technique are much better than other extraction methods.

Reversibly tuning the mechanical properties of a DNA hydrogel by a DNA nanomotor.

By integrating a DNA motor based on an i-motif sequence that undergoes a pH-dependent conformational transition into a DNA hydrogel network, such microscopic transition leads to a macroscopic change in mechanical properties. This strategy allows reversible tuning of the mechanical strength of the hydrogel ranging from 250 Pa to 1000 Pa.

Bioactive sesquiterpene polyol esters from the leaves of Tripterygium wilfordii.

Tripterygium wilfordii, a member of Celastraceae family, has been used as a traditional plant insecticide and a medicinal plant. Phytochemical investigation of the leaves of T. wilfordii has resulted in the isolation of eight sesquiterpene polyol esters triptersinines M-T (1-8) and one sesquiterpene pyridine alkaloid (9). The structures of the compounds were elucidated on the basis of spectroscopic data analyses, including UV, IR, MS, and NMR experiments. The inhibitory effects on nitric oxide production in LPS-induced macrophages of 1-9 were also evaluated.

[Biomechanical study on a novel injectable calcium phosphate cement containing poly (latic-co-glycolic acid) in repairing tibial plateau fractures].

OBJECTIVE: To investigate the biomechanics of a novel injectable calcium phosphate cement (CPC) composited by poly (lactic-co-glycolic acid) (PLGA) combined with double-screw fixation in repairing Schatzker II type tibial plateau fracture, so as to provide the mechanical basis for the clinical minimally invasive treatment. METHODS: Ten matched pairs of proximal tibia specimens were harvested from 10 elderly cadavers to prepare Schatzker II type tibial plateau fracture model. Fracture was fixed by forcing injection of CPC (experimental group) or autologous cancellous bone (control group) combined with double-screw fixation. The samples underwent axial compression on MTS 858 material testing machine to measure the load-displacement, the maximum load, and compressive stiffness. RESULTS: The novel CPC had good injectable property at room temperature, which could fill in bone defect fully and permeated into the surrounding cancellous bone. The average bone mineral density of tibial metaphysis was (0.639 +/- 0.081) g/cm2 in the experimental group and (0.668 +/- 0.083) g/cm2 in the control group, showing no significant difference (t=1.012, P=0.331). The maximum load in the experimental group [(4 101 +/- 813) N] was significantly higher than that in the control group [(692 +/- 138) N] (t=3.932, P=0.001). The compressive stiffness was (1 363 +/- 362) N/mm in the experimental group and was (223 +/- 54) N/mm in the control group, showing significant difference (t=3.023, P=0.013). CONCLUSION: The novel CPC can effectively restore the biomechanical properties of tibilal plateau in repairing Schatzker II type tibial plateau fracture by means of forcing injection combining with double-screw fixation. It could be used as an effective bone substitute in the clinical application.