Negatively charged phospholipids accelerate the membrane fusion activity of the plant-specific insert domain of an aspartic protease.

Various plants use antimicrobial proteins/peptides to resist phytopathogens. In the potato, Solanum tuberosum, the plant-specific insert (PSI) domain of an aspartic protease performs this role by disrupting phytopathogen plasma membranes. However, the mechanism by which PSI selects target membranes has not been elucidated. Here, we studied PSI-induced membrane fusion, focusing on the effects of lipid composition on fusion efficiency. Membrane fusion by the PSI involves an intermediate state whereby adjacent liposomes share their bilayers. We found that increasing the concentration of negatively charged phosphatidylserine (PS) phospholipids substantially accelerated PSI-mediated membrane fusion. NMR data demonstrated that PS did not affect the binding between the PSI and liposomes but had seminal effects on the dynamics of PSI interaction with liposomes. In PS-free liposomes, the PSI underwent significant motion, which was suppressed on PS-contained liposomes. Molecular dynamics simulations showed that the PSI binds to PS-containing membranes with a dominant angle ranging from -31° to 30°, with respect to the bilayer, and is closer to the membrane surfaces. In contrast, PSI is mobile and exhibits multiple topological states on the surface of PS-free membranes. Taken together, our data suggested that PS lipids limit the motion of the anchored PSI, bringing it closer to the membrane surface and efficiently bridging different liposomes to accelerate fusion. As most phytopathogens have a higher content of negatively charged lipids as compared with host cells, these results indicate that the PSI selectively targets negatively charged lipids, which likely represents a way of distinguishing the pathogen from the host.

Crowded Environment Regulates the Coacervation of Biopolymers via Nonspecific Interactions.

The membrane-less organelles (MLOs) with subcompartments are formed via liquid-liquid phase separation (LLPS) in the crowded cell interior whose background molecules are up to 400 mg/mL. It is still a puzzle how the background molecules regulate the formation, dynamics, and functions of MLOs. Using biphasic coacervate droplets formed by poly(l-lysine) (PLL), quaternized dextran (Q-dextran), and single-stranded oligonucleotides (ss-oligo) as a model of MLO, we online monitored the LLPS process in Bovine Serine Albumin (BSA) solution up to 200.0 mg/mL. Negatively charged BSA is able to form complex or coacervate with positively charged PLL and Q-dextran and thus participates in the LLPS via nonspecific interactions. Results show that BSA effectively regulates the LLPS by controlling the phase distribution, morphologies, and kinetics. With increasing BSA concentration, the spherical biphasic droplets evolve in sequence into phase-inverted flower-like structure, worm-like chains, network structures, and confined coacervates. Each kind of morphology is formed via its own specific growth and fusion pathway. Our work suggests that MLOs could be controlled solely by the crowded environment and provides a further step toward understanding the life process in cell.

An arbuscular mycorrhizal fungus differentially regulates root traits and cadmium uptake in two maize varieties.

Arbuscular mycorrhizal fungi (AMF) are symbiotic fungi that colonize plant roots, and they are more common in Cd-polluted habitats. However, there is limited understanding of the response of root traits and cadmium (Cd) uptake to AMF in different crop varieties. Two maize varieties, Panyu 3 and Ludan 8, with high and low Cd uptake capacities, respectively, were cultivated as host plants in a pot experiment with Cd-polluted soil (17.1 mg/kg Cd). The effects of AMF on the growth, mineral nutrient concentration, root traits, phytohormone concentrations and Cd uptake of the two maize varieties and their comprehensive response to AMF fungal inoculation were investigated. AMF improved growth, mineral nutrient levels and root morphology and increased lignin and phytohormone concentrations in roots and Cd uptake in the two maize varieties. However, the two maize varieties, Panyu 3 and Ludan 8, had different responses to AMF, and their comprehensive response indices were 753.6% and 389.4%, respectively. The root biomass, branch number, abscisic acid concentrations, lignin concentrations and Cd uptake of maize Panyu 3 increased by 151.1%, 28.6%, 139.7%, 99.5% and 84.7%, respectively. The root biomass, average diameter, auxin concentration, lignin concentration and Cd uptake of maize Ludan 8 increased by 168.7%, 31.8%, 31.4%, 41.7% and 136.7%, respectively. Moreover, Cd uptake in roots presented very significant positive correlations with the average root diameter and abscisic acid concentration. A structural equation model indicated that the root abscisic acid concentration and root surface area had positive effects on Cd uptake by the Panyu 3 maize roots; the root abscisic acid concentration and root tip number had positive effects on Cd uptake by the Ludan 8 maize roots. Thus, AMF differentially regulated Cd uptake in the two maize varieties, and the regulatory effect was closely related to root traits and phytohormone concentrations.

The fate and risk of microplastic and antibiotic sulfamethoxazole coexisting in the environment.

With huge amount of plastic entering to the environment, microplastic pollution has become a great concern. Microplastic behavior in the environment is important to evaluate its harm to ecosystem and human beings. It has been found that microplastic can be used as a carrier to adsorb and enrich heavy metals or organic pollutants in water or soil. With the development of industry and medicine, antibiotics are improperly used in many countries and most of them end up in wastewater. This study investigates the adsorption behavior of sulfamethoxazole (SMX) antibiotic onto virgin and aged polyamide 6 (PA6) microplastics. The maximum adsorption amount was 0.089 mg SMX/g PA6 at 25 °C and pH 7 with initial SMX concentration of 2 mg/L. Results reveal that the adsorption was mainly due to the chemical bounding. The impact of pH, salinity, and humic acid on the adsorption have been studied, and it was found that the pH has significant impact on the adsorption. At pH 5, the adsorption amount was 0.27 mg/g which is two times higher than that at pH 7. The SMX adsorbed on PA6 tends to be more likely desorbed in reservoir water than in ultrapure water. For instance, the desorption amount of SMX from virgin PA6 was 0.15 mg/L in reservoir water but 0.10 mg/L in ultrapure water. The study indicates that microplastics have great threat to environment.

Coacervate Formed by an ATP-Binding Aptamer and Its Dynamic Behavior under Nonequilibrium Conditions.

Although numerous protocell models have been developed to explore the possible pathway of the origin of life on the early earth, few truly fulfill the roles of the DNA/RNA sequence and ATP molecules, which are keys to cell replication and evolution. The ATP-binding aptamer offers an opportunity to combine sequence and energy molecules. In this work, we choose the coacervate droplet as the protocell model and investigate the interaction of the DNA aptamer, poly(l-lysine)(PLL), and ATP under varying conditions. PLL and aptamers form solid precipitates, which spontaneously transform to coacervate droplets as ATP is introduced. The selective uptake and sequestration of exogenous molecules is achieved by the ATP-containing coacervates. As an electric field is applied to expel ATP, the portion of the droplet deficient in ATP becomes solid. The solid/liquid phase ratio is tunable by varying the electric field strength and excitation time. Together with the vacuolization process, a solid head with a soft mouth periodically opening and closing is created. Moreover, the composite coacervate droplet gradually grows as it is treated with an electric field and cannot recover to the original liquid phase after the power is turned off and replenished with ATP. Our work highlights that the proper integration of the DNA sequence, ATP, and energy input could be a powerful strategy for creating a protocell with certain living features.

Full components conversion of lignocellulose via a closed-circuit biorefinery process on a pilot scale.

This study developed a closed-circuit biorefinery process for full conversion of lignocellulose into ethanol, biogas and organic fertilizer with zero waste on a pilot scale. In the process, subcritical water pretreatment could effectively break the structure of wheat straw (WS), and ethanol was obtained from pretreated wheat straw (PWS) using two batches of simultaneous saccharification and fermentation (SSF). The pretreatment and ethanol fermentation wastes were reused for biogas and organic fertilizer production by anaerobic digestion (AD), whereas the pretreatment and ethanol conversion efficiency were reduced when supernatant after AD was recovered for next batch pretreatment. The yields of ethanol (0.08-0.09 g/g), biogas (0.05-0.10 L/g) and organic fertilizer (0.55-0.79 g/g) were demonstrated through mass balance. Furthermore, the hidden problems were exposed on pilot-scale conversion process, and several strategies were provided for optimizing the biorefinery process in the future.

The potential utilization of slag generated from iron- and steelmaking industries: a review.

Along with iron and steel production, large amount of slag is generated. Proper management on the iron- and steelmaking slag is highly demanded due to the high cost of direct disposal of the slag to landfill, which is the most adopted management approach. In this article, the potential application of iron- and steelmaking slag has been reviewed, which included the slag utilization in construction as cement and sand, in water, soil, and gas treatment, as well as in value material recovery. In addition, the challenge and required effort to be made in iron- and steelmaking slag management have been discussed.

Current advances in the development of natural meniscus scaffolds: innovative approaches to decellularization and recellularization.

The increasing rate of injuries to the meniscus indicates the urgent need to develop effective repair strategies. Irreparably damaged menisci can be replaced and meniscus allografts represent the treatment of choice; however, they have several limitations, including availability and compatibility. Another approach is the use of artificial implants but their chondroprotective activities are still not proved clinically. In this situation, tissue engineering offers alternative natural decellularized extracellular matrix (ECM) scaffolds, which have shown biomechanical properties comparable to those of native menisci and are characterized by low immunogenicity and promising regenerative potential. In this article, we present an overview of meniscus decellularization methods and discuss their relative merits. In addition, we comparatively evaluate cell types used to repopulate decellularized scaffolds and analyze the biocompatibility of the existing experimental models. At present, acellular ECM hydrogels, as well as slices and powders, have been explored, which seems to be promising for partial meniscus regeneration. However, their inferior biomechanical properties (compressive and tensile stiffness) compared to natural menisci should be improved. Although an optimal decellularized meniscus scaffold still needs to be developed and thoroughly validated for its regenerative potential in vivo, we believe that decellularized ECM scaffolds are the future biomaterials for successful structural and functional replacement of menisci.

Hierarchically Biomimetic Scaffolds with Anisotropic Micropores and Nanotopological Patterns to Promote Bone Regeneration via Geometric Modulation.

Structural engineering is an appealing means to modulate osteogenesis without the intervention of exogenous cells or therapeutic agents. In this work, a novel 3D scaffold with anisotropic micropores and nanotopographical patterns is developed. Scaffolds with oriented pores are fabricated via the selective extraction of water-soluble polyethylene oxide from its poly(ε-caprolactone) co-continuous mixture and uniaxial stretching. The plate apatite-like lamellae are subsequently hatched on the pore walls through surface-induced epitaxial crystallization. Such a unique geometric architecture yields a synergistic effect on the osteogenic capability. The prepared scaffold leads to a 19.2% and 128.0% increase in the alkaline phosphatase activity of rat bone mesenchymal stem cells compared to that of the scaffolds with only oriented pores and only nanotopographical patterns, respectively. It also induces the greatest upregulation of osteogenic-related gene expression in vitro. The cranial defect repair results demonstrate that the prepared scaffold effectively promotes new bone regeneration, as indicated by a 350% increase in collagen I expression in vivo compared to the isotropic porous scaffold without surface nanotopology after implantation for 14 weeks. Overall, this work provides geometric motifs for the transduction of biophysical cues in 3D porous scaffolds, which is a promising option for tissue engineering applications.

Oral Microbiota and Porphyromonas gingivalis Kgp Genotypes Altered in Parkinson's Disease with Mild Cognitive Impairment.

Cognitive impairment (CI) is a common complication of the non-motor symptoms in Parkinson's disease (PD), including PD with mild cognitive impairment (PD-MCI) and PD dementia. Recent studies reported the oral dysbiosis in PD and CI, respectively. Porphyromonas gingivalis (P. gingivalis), a pathogen of oral dysbiosis, plays an important role in PD, whose lysine-gingipain (Kgp) could lead to AD-type pathologies. No previous study investigated the composition of oral microbiota and role of P. gingivalis in PD-MCI. This study aimed to investigate the differences of oral microbiota composition, P. gingivalis copy number, and Kgp genotypes among PD-MCI, PD with normal cognition (PD-NC) and periodontal status-matched control (PC) groups. The oral bacteria composition, the copy number of P. gingivalis, and the Kgp genotypes in gingival crevicular fluid from PD-MCI, PD-NC, and PC were analyzed using 16S ribosomal RNA sequencing, quantitative real-time PCR, and MseI restriction. We found that the structures of oral microbiota in PD-MCI group were significantly different compared to that in PD-NC and PC group. The relative abundances of Prevotella, Lactobacillus, Megasphaera, Atopobium, and Howardella were negatively correlated with cognitive score. Moreover, there was a significant difference of Kgp genotypes among the three groups. The predominant Kgp genotypes of P. gingivalis in the PD-MCI group were primarily Kgp II, whereas in the PD-NC group, it was mainly Kgp I. The Kgp II correlated with lower MMSE and MoCA scores, which suggested that Kgp genotypes II is related to cognitive impairment in PD.

Understanding the multi-functionality and tissue-specificity of decellularized dental pulp matrix hydrogels for endodontic regeneration.

Dental pulp is the only soft tissue in the tooth which plays a crucial role in maintaining intrinsic multi-functional behaviors of the dentin-pulp complex. Nevertheless, the restoration of fully functional pulps after pulpitis or pulp necrosis, termed endodontic regeneration, remained a major challenge for decades. Therefore, a bioactive and in-situ injectable biomaterial is highly desired for tissue-engineered pulp regeneration. Herein, a decellularized matrix hydrogel derived from porcine dental pulps (pDDPM-G) was prepared and characterized through systematic comparison against the porcine decellularized nerve matrix hydrogel (pDNM-G). The pDDPM-G not only exhibited superior capabilities in facilitating multi-directional differentiation of dental pulp stem cells (DPSCs) during 3D culture, but also promoted regeneration of pulp-like tissues after DPSCs encapsulation and transplantation. Further comparative proteomic and transcriptome analyses revealed the differential compositions and potential mechanisms that endow the pDDPM-G with highly tissue-specific properties. Finally, it was realized that the abundant tenascin C (TNC) in pDDPM served as key factor responsible for the activation of Notch signaling cascades and promoted DPSCs odontoblastic differentiation. Overall, it is believed that pDDPM-G is a sort of multi-functional and tissue-specific hydrogel-based material that holds great promise in endodontic regeneration and clinical translation. STATEMENT OF SIGNIFICANCE: Functional hydrogel-based biomaterials are highly desirable for endodontic regeneration treatments. Decellularized extracellular matrix (dECM) preserves most extracellular matrix components of its native tissue, exhibiting unique advantages in promoting tissue regeneration and functional restoration. In this study, we prepared a porcine dental pulp-derived dECM hydrogel (pDDPM-G), which exhibited superior performance in promoting odontogenesis, angiogenesis, and neurogenesis of the regenerating pulp-like tissue, further showed its tissue-specificity compared to the peripheral nerve-derived dECM hydrogel. In-depth proteomic and transcriptomic analyses revealed that the activation of tenascin C-Notch axis played an important role in facilitating odontogenic regeneration. This biomaterial-based study validated the great potential of the dental pulp-specific pDDPM-G for clinical applications, and provides a springboard for research strategies in ECM-related regenerative medicine.

Amines-mediated ß-glucose pentaacetate to generate photoluminescent polymer-carbon nanodots for visual monitoring the freshness of shrimp.

In this paper, a portable fluorescence-based functional hydrogel loaded with ß-d-glucose pentaacetate (ß-D-GP) is designed for high-sensitive quantification of amine vapor and visual monitoring of freshness of shrimp. We found for the first time that amine vapor can mediate ß-D-GP to generate photoluminescent polymer-carbon nanodots (PCNDs) with good optical properties. On this basis, a functional hydrogel sensing platform is simply formed by solidifying ß-D-GP in agarose hydrogels. When exposure to the volatile amines released from the spoilage of shrimp, ß-D-GP in hydrogel is immediately mediated by amines to generate PCNDs, resulting in obvious fluorescence-based color variation of functional hydrogel. Notably, a smartphone is used to obtain digital photographs and RGB (Red/Green/Blue) information of hydrogels for on-site quantitative analysis. The gray value of G/(R + B) of hydrogel shows good linearity with trimethylamine (TMA) vapor concentration in the range of 0-59.49 × 10-9 mol dm-3. More importantly, the G/(R + B) value of functional hydrogel is successfully used to assess the freshness of shrimp. Consequently, this strategy provides a low-cost, portable fluorescence analysis device with promising applications in achieving high-sensitive, nondestructive, and on-site food safety evaluation of animal-derived aquatic products.

Bioactive Decellularized Extracellular Matrix Hydrogel Microspheres Fabricated Using a Temperature-Controlling Microfluidic System.

Hydrogel microspheres have drawn great attention as functional three-dimensional (3D) microcarriers for cell attachment and growth, which have shown great potential in cell-based therapies and biomedical research. Hydrogels derived from a decellularized extracellular matrix (dECM) retain the intrinsic physical and biological cues from the native tissues, which often exhibit high bioactivity and tissue-specificity in promoting tissue regeneration. Herein, a novel two-stage temperature-controlling microfluidic system was developed which enabled production of pristine dECM hydrogel microspheres in a high-throughput manner. Porcine decellularized peripheral nerve matrix (pDNM) was used as the model raw dECM material for continuous generation of pDNM microgels without additional supporting materials or chemical crosslinking. The sizes of the microspheres were well-controlled by tuning the feed ratios of water/oil phases into the microfluidic device. The resulting pDNM microspheres (pDNM-MSs) were relatively stable, which maintained a spherical shape and a nanofibrous ultrastructure for at least 14 days. Schwann cells and PC12 cells preseeded on the pDNM-MSs not only showed excellent viability and an adhesive property, but also promoted cell extension compared to the commercially available gelatin microspheres. Moreover, primary neural stem/progenitor cells attached well to the pDNM-MSs, which further facilitated their proliferation. The successfully fabricated dECM hydrogel microspheres provided a highly bioactive microenvironment for 3D cell culture and functionalization, which showed promising potential in versatile biomedical applications.

Integrating enzymatic hydrolysis into subcritical water pretreatment optimization for bioethanol production from wheat straw.

The conversion of lignocellulosic biomass to bioethanol is a potential approach to alleviate the energy crisis and environmental deterioration. To improve the conversion efficiency of bioethanol from wheat straw (WS), the optimization of subcritical water pretreatment and high solid hydrolysis were investigated in this study. Response surface methodology (RSM) accompanied with glucose concentration after enzymatic hydrolysis as a more reasonable response value was applied for the pretreatment optimization, and the optimum conditions were obtained as 220.51 °C of extraction temperature, 22.01 min of extraction time and 2.50% (w/v) of substrate loading. After pretreatment, the hemicellulose decreased by 18.37%, and the cellulose and lignin increased by 25.92% and 8.81%, respectively, which were consistent with the destroyed microstructure and raised crystallinity. The high efficiency of separate hydrolysis and fermentation (SHF) was verified by five commercial cellulases, and yields of hydrolysis and fermentation were 77.85-89.59% and 93.34-96.18%, respectively. Based on the high solid (15%) hydrolysis and fermentation, the ethanol concentration was significantly improved to 37.00 g/L. Interestingly, 64.47% of lignin was accumulated in the solid residue after enzymatic hydrolysis and it did not affect the efficiency of SHF, which further suggested that subcritical water mainly affected the structure of WS rather than the removal of lignin. Therefore, subcritical water pretreatment combined with high solid hydrolysis is a more effective solution for bioethanol conversion, which is also a promising strategy to utilize all components of lignocellulosic biomass.

The removal of microplastics in the wastewater treatment process and their potential impact on anaerobic digestion due to pollutants association.

Microplastics are abundant in municipal wastewater which is mainly from personal care products and laundry. In recent years, great attention has been given to microplastics removal in wastewater treatment. In this article, the study focusing on microplastics in wastewater has been evaluated with VOSviewer. It was found that the major interest was in identification, quantification and pollution of the microplastics in the wastewater, and their transportation and final destination during wastewater treatment processes. The major microplastics and their shapes in wastewater were reviewed. Our evaluation results were consistent with other reported that fibers and fragment were the majority in terms of shape and polyethylene terephthalare (PET), polyethylene (PE), polypropylene (PP), and polystyrene (PS) are the most presented microplastics in wastewater. During wastewater treatment, the removal route of microplastics from wastewater includes settling, adsorption, entrapment, interception, etc. It confirms that microplastics are just simply transferred from wastewater to sludge. It could then bring problems to anaerobic digestion as microplastics are great vector for toxic substances such as antibiotics and persistence organic pollutants. The key to determine the microplastics effect on anaerobic digestion is the desorption behavior of the toxic substances such as antibiotics, persistent organic pollutants and heavy metals from microplastics in digestion condition. Toxic compounds which are commonly presenting in sludge have shown the tendency to release from microplastics. It indicates that microplastics in sludge have great possibility to impact on methane production.

Materials and Designs for Wearable Photodetectors.

Photodetectors (PDs), as an indispensable component in electronics, are highly desired to be flexible to meet the trend of next-generation wearable electronics. Unfortunately, no in-depth reviews on the design strategies, material exploration, and potential applications of wearable photodetectors are found in literature to date. Thus, this progress report first summarizes the fundamental design principles of turning "hard" photodetectors "soft," including 2D (polymer and paper substrate-based devices) and 1D PDs (fiber shaped devices). In short, the flexibility of PDs is realized through elaborate substrate modification, material selection, and device layout. More importantly, this report presents the current progress and specific requirements for wearable PDs according to the application: monitoring, imaging, and optical communication. Challenges and future research directions in these fields are proposed at the end. The purpose of this progress report is not only to shed light on the basic design principles of wearable PDs, but also serve as the roadmap for future exploration in wearable PDs in various applications, including health monitoring and Internet of Things.

Desktop-stereolithography 3D printing of a radially oriented extracellular matrix/mesenchymal stem cell exosome bioink for osteochondral defect regeneration.

Mitochondrial dysfunction and oxidative stress damage are hallmarks of osteoarthritis (OA). Mesenchymal stem cell (MSC)-derived exosomes are important in intercellular mitochondria communication. However, the use of MSC exosomes for regulating mitochondrial function in OA has not been reported. This study aimed to explore the therapeutic effect of MSC exosomes in a three dimensional (3D) printed scaffold for early OA therapeutics. Methods: We first examined the mitochondria-related proteins in normal and OA human cartilage samples and investigated whether MSC exosomes could enhance mitochondrial biogenesis in vitro. We subsequently designed a bio-scaffold for MSC exosomes delivery and fabricated a 3D printed cartilage extracellular matrix (ECM)/gelatin methacrylate (GelMA)/exosome scaffold with radially oriented channels using desktop-stereolithography technology. Finally, the osteochondral defect repair capacity of the 3D printed scaffold was assessed using a rabbit model. Results: The ECM/GelMA/exosome scaffold effectively restored chondrocyte mitochondrial dysfunction, enhanced chondrocyte migration, and polarized the synovial macrophage response toward an M2 phenotype. The 3D printed scaffold significantly facilitated the cartilage regeneration in the animal model. Conclusion: This study demonstrated that the 3D printed, radially oriented ECM/GelMA/exosome scaffold could be a promising strategy for early OA treatment.

Periosteum Extracellular-Matrix-Mediated Acellular Mineralization during Bone Formation.

Cell-mediated mineralization is essential for bone formation and regeneration. In this study, it is proven that extracellular matrix (ECM) of decellularized periosteum can play an initiative and independent role in bone-like apatite formation. Using decellularized periosteum scaffold, it is revealed that ECM scaffold itself can promote critical bone defect regeneration and nude mouse ectopic ossification. The natural collagen matrix of decellularized periosteum can serve as a 3D structural template for Ca-P nuclei initiation, controlling the size and orientation of bone-like mineral crystals. The naturally cross-linked and highly ordered 3D fibrillar network of decellularized periosteum not only provides a model for mimicking mineralization in vitro and in vivo to elucidate the important functions of ECM in bone formation and regeneration, but also can be a promising biomaterial for bone tissue engineering and clinical application.