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Summary: High serum urate levels are the major risk factor for gout. URAT1, the primary transporter for urate absorption in the kidneys, is well known as an anti-hyperuricemia drug target. However, the clinical application of URAT1-targeted drugs is limited because of their low specificity and severe side effects. The lack of structural information impedes elucidation of the transport mechanism and the development of new drugs. Here, we present the cryoelectron microscopy (cryo-EM) structures of human URAT1(R477S), its complex with urate, and its closely related homolog OAT4. URAT1(R477S) and OAT4 exhibit major facilitator superfamily (MFS) folds with outward- and inward-open conformations, respectively. Structural comparison reveals a 30° rotation between the N-terminal and C-terminal domains, supporting an alternating access mechanism. A conserved arginine (OAT4-Arg473/URAT1-Arg477) is found to be essential for chloride-mediated inhibition. The URAT1(R477S)-urate complex reveals the specificity of urate recognition. Taken together, our study promotes our understanding of the transport mechanism and substrate selection of URAT1.

Abstract Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) are two primary components of the eukaryotic membrane and play essential roles in the maintenance of membrane integrity, lipid droplet biogenesis, autophagosome formation, and lipoprotein formation and secretion. Choline/ethanolamine phosphotransferase 1 (CEPT1) catalyzes the last step of the biosynthesis of PC and PE in the Kennedy pathway by transferring the substituted phosphate group from CDP-choline/ethanolamine to diacylglycerol. Here, we present the cryo-EM structures of human CEPT1 and its complex with CDP-choline at resolutions of 3.7 Å and 3.8 Å, respectively. CEPT1 is a dimer with 10 transmembrane segments (TMs) in each protomer. TMs 1-6 constitute a conserved catalytic domain with an interior hydrophobic chamber accommodating a PC-like density. Structural observations and biochemical characterizations suggest that the hydrophobic chamber coordinates the acyl tails during the catalytic process. The PC-like density disappears in the structure of the complex with CDP-choline, suggesting a potential substrate-triggered product release mechanism.

IntroductionLaboratory teaching of medical microbiology involves highly pathogenic microorganisms, thus posing potential biosafety risks to the students and the teacher. To address these risks, non/low-pathogenic microorganisms were modified to mimic highly pathogenic ones or highly pathogenic microorganisms were attenuated directly using the CRISPR/Cas9 technology. This study describes the modification of Escherichia coli DH5α to mimic Shigella and its evaluation as a safe alternative for medical laboratory teaching.MethodsTo generate E. coli DH5α△FliC△tnaA2a, the tnaA and FliC genes in E. coli DH5α were knocked out using CRISPR/Cas9 technology; a plasmid bearing the O-antigen determinant of S. flexneri 2a was then constructed and transformed. Acid tolerance assays and guinea pig eye tests were used to assess the viability and pathogenicity, respectively. Questionnaires were used to analyze teaching effectiveness and the opinions of teachers and students.ResultsThe survey revealed that most teachers and students were inclined towards real-time laboratory classes than virtual classes or observation of plastic specimens. However, many students did not abide by the safety regulations, and most encountered potential biosafety hazards in the laboratory. E. coli DH5α△FliC△tnaA2a was biochemically and antigenically analogous to S. flexneri 2a and had lower resistance to acid than E. coli. There was no toxicity observed in guinea pigs. Most of teachers and students were unable to distinguish E. coli DH5α△FliC△tnaA2a from pure S. flexneri 2a in class. Students who used E. coli DH5α△FliC△tnaA2a in their practice had similar performance in simulated examinations compared to students who used real S. flexneri 2a, but significantly higher than the virtual experimental group.DiscussionThis approach can be applied to other high-risk pathogenic microorganisms to reduce the potential biosafety risks in medical laboratory-based teaching and provide a new strategy for the development of experimental materials.

Nano-optomechanical systems plays an indispensable role in all-optical manipulation of light but high energy losses severely limit their development. Here the authors show ultrafast all-optical manipulation in a sub-5 nm tip-supported optomechanical metasurface.

The authors present a subcutaneous power supply which coverts NIR-II light to electricity via combination of photothermal conversion and thermoelectric conversion. They demonstrate that it can recharge an implanted wireless camera upon irradiation with NIR-II light through the skin.

BackgroundDrug resistance is a prominent problem in the treatment of tuberculosis, so it is urgent to develop new anti- tuberculosis drugs. Here, we investigated the effects and mechanisms of cisplatin (DDP) on intracellular Mycobacterium smegmatis to tap the therapeutic potential of DDP in mycobacterial infection.ResultsMacrophages infected with Mycobacterium smegmatis were treated with DDP alone or combined with isoniazid or rifampicin. The results showed that the bacterial count in macrophages decreased significantly after DDP (≤ 6 μg/mL) treatment. When isoniazid or rifampicin was combined with DDP, the number of intracellular mycobacteria was also significantly lower than that of isoniazid or rifampicin alone. Apoptosis of infected cells increased after 24 h of DDP treatment, as shown by flow cytometry and transmission electron microscopy detection. Transcriptome sequencing showed that there were 1161 upregulated and 645 downregulated differentially expressed genes (DEGs) between the control group and DDP treatment group. A Trp53-centered protein interaction network was found based on the top 100 significant DEGs through STRING and Cytoscape software. The expression of phosphorylated p53, Bax, JAK, p38 MAPK and PI3K increased after DDP treatment, as shown by Western blot analysis. Inhibitors of JAK, PI3K or p38 MAPK inhibited the increase in cell apoptosis and the reduction in the intracellular bacterial count induced by DDP. The p53 promoter Kevetrin hydrochloride scavenges intracellular mycobacteria. If combined with DDP, Kevetrin hydrochloride could increase the effect of DDP on the elimination of intracellular mycobacteria. In conclusion, DDP at low concentrations could activate the JAK, p38 MAPK and PI3K pathways in infected macrophages, promote the phosphorylation of p53 protein, and increase the ratio of Bax to Bcl-2, leading to cell apoptosis, thus eliminating intracellular bacteria and reducing the spread of mycobacteria.ConclusionDDP may be a new host-directed therapy for tuberculosis treatment, as well as the p53 promoter Kevetrin hydrochloride.

BackgroundThe Enterovirus D68 (EV-D68) epidemic has increased knowledge of the virus as a pathogen capable of causing serious respiratory and neurological illnesses. It has been shown that long noncoding RNAs (lncRNAs) regulate viral replication and infection via multiple mechanisms or signaling pathways. However, the precise function of lncRNAs in EV-D68 infection remains unknown.MethodsThe differential expression profiles of lncRNA in EV-D68-infected and uninfected rhabdomyosarcoma (RD) cells were studied using high-throughput sequencing technology. The knockdown through small interfering RNA (siRNA) and overexpression of lncRNA SNHG9 (small ribonucleic acid host gene 9) were applied to investigate how lncRNA SNHG9 regulates EV-D68 propagation. The targeted interactions of lncRNA SNHG9 with miR-150-5p and miR-150-5p with c-Fos were validated using dual luciferase reporter system. LncRNA SNHG9 knockdown and miR-150-5p inhibitor were co-transfected with RD cells. QRT-PCR and western blot were used to detect RNA and protein levels, of c-Fos and VP1, respectively. Median tissue culture infectious dose (TCID50) was applied to detect viral titers.ResultsThe results demonstrated that a total of 375 lncRNAs were highly dysregulated in the EV-D68 infection model. In the EV-D68 infection model, lncRNA SNHG9 and c-Fos were increased in EV-D68-infected RD cells. However, the expression level of miR-150-5p was downregulated. In addition, overexpression of SNHG9 in RD cells resulted in decreased viral replication levels and viral titers following infection with EV-D68, and further experiments revealed that overexpression of SNHG9 inhibited the viral replication by targeting increased miR-150-5p binding and significantly increased c-Fos expression in RD cells.ConclusionOur findings indicate that the SNHG9/miR-150-5p/c-Fos axis influences EV-D68 replication in host cells and that SNHG9 may be a possible target for anti-EV-D68 infection therapies.

Intercropping systems have been studied as a sustainable agricultural planting pattern to increase soil quality and crop yields. However, the relationships between metabolites and soil physicochemical properties remain poorly understood under sugarcane/peanut intercropping system. Thus, we determined the rhizosphere soil physicochemical properties, and analyzed rhizosphere soil metabolites and root metabolites by metabolomics method under monoculture and intercropping patterns of sugarcane and peanut. The results showed that pH, the contents of total phosphorus (P), total potassium (K), available nitrogen (N), available phosphorus (P), and available potassium (K) were higher in rhizosphere soil of intercropping peanut than monoculture peanut, and the content of total P was higher in rhizosphere soil of intercropping sugarcane than monoculture sugarcane. Sugarcane/peanut intercropping also significantly increased the activities of acid phosphatase and urease in rhizosphere soil. The metabolomics results showed that 32 metabolites, mainly organic acids and their derivatives (25.00%), nucleotides and their metabolites (18.75%), were detected in root and rhizosphere soil samples. In the MP-S (rhizosphere soil of monoculture peanut) vs. IP-S (rhizosphere soil of intercropping peanut) comparison, 47 differential metabolites (42 upregulated) were screened, including glycerolipids (19.15%), organic acids and their derivatives (17.89%), and amino acids and their metabolites (12.77%). In the MS-S (rhizosphere soil of monoculture sugarcane) vs. IS-S (rhizosphere soil of intercropping sugarcane) comparison, 51 differential metabolites (26 upregulated) were screened, including heterocyclic compounds (15.69%), glycerolipids (11.76%), and organic acids and their derivatives (9.80%). The metabolite species from MP-S, MS-S, IP-S, and IS-S were similar, but some metabolite contents were significantly different, such as adenine, adenosine, maltotriose, thermozeaxanthin-13 and PE-NMe (20:0/24:0). Adenine and adenosine were detected in root and rhizosphere soils, and their levels were increased in the intercropping treatment, which were mainly related to enhanced purine metabolism in root and rhizosphere soils under the sugarcane/peanut intercropping system. Importantly, adenine and adenosine were significantly positively correlated with total P and total K contents, acid phosphatase and urease activities, and pH. This study clarified that the sugarcane/peanut intercropping system could improve soil nutrients and enzymes and was related to purine metabolism.

Abstract Background With the advancement of sequencing technologies, a plethora of noncoding RNA (ncRNA) species have been widely discovered, including microRNAs (miRNAs), circular RNAs (circRNAs), and long ncRNAs (lncRNAs). However, the mechanism of these non-coding RNAs in diseases caused by enterovirus d68 (EV-D68) remains unclear. The goal of this research was to identify significantly altered circRNAs, lncRNAs, miRNAs, and mRNAs pathways in RD cells infected with EV-D68, analyze their target relationships, demonstrate the competing endogenous RNA (ceRNA) regulatory network, and evaluate their biological functions. Methods The total RNAs were sequenced by high-throughput sequencing technology, and differentially expressed genes between control and infection groups were screened using bioinformatics method. We discovered the targeting relationship between three ncRNAs and mRNA using bioinformatics methods, and then built a ceRNA regulatory network centered on miRNA. The biological functions of differentially expressed mRNAs (DEmRNAs) were discovered through GO and KEGG enrichment analysis. Create a protein interaction network (PPI) to seek for hub mRNAs and learn more about protein–protein interactions. The relative expression was verified using RT-qPCR. The effects of Fos and ARRDC3 on virus replication were confirmed using RT-qPCR, virus titer (TCID50/ml), Western blotting. Results 375 lncRNAs (154 upregulated and 221 downregulated), 33 circRNAs (32 upregulated and 1 downregulated), 96 miRNAs (49 upregulated and 47 downregulated), and 239 mRNAs (135 upregulated and 104 downregulated) were identified as differently in infected group compare to no-infected group. A single lncRNA or circRNA can be connected with numerous miRNAs, which subsequently coregulate additional mRNAs, according to the ceRNA regulatory network. The majority of DEmRNAs were shown to be connected to DNA binding, transcription regulation by RNA polymerase II, transcription factor, MAPK signaling pathways, Hippo signal pathway, and apoptosis pathway, according to GO and KEGG pathway enrichment analysis. The hub mRNAs with EGR1, Fos and Jun as the core were screened through PPI interaction network. We preliminarily demonstrated that the Fos and ARRDC3 genes can suppress EV-D68 viral replication in order to further verify the results of full transcriptome sequencing. Conclusion The results of whole transcriptome analysis after EV-D68 infection of RD cells were first reported in this study, and for the first time, a ceRNA regulation network containing miRNA at its center was established for the first time. The Fos and ARRDC3 genes were found to hinder viral in RD cells. This study establishes a novel insight host response during EV-D68 infection and further investigated potential drug targets.

Osteosarcoma is one of the most common primary malignant bone tumors, mainly occurring in children and adolescents, and is characterized by high morbidity and poor prognosis. MicroRNAs, a class of noncoding RNAs consisting of 19 to 25 nucleotides, are involved in cell proliferation, invasion, metastasis, and apoptosis to regulate the development and progression of osteosarcoma. Studies have found that microRNAs are closely related to the diagnosis, treatment, and prognosis of osteosarcoma patients and have an important role in improving drug resistance in osteosarcoma. This paper reviews the role of microRNAs in the pathogenesis of osteosarcoma and their clinical value, aiming to provide a new research direction for diagnosing and treating osteosarcoma and achieving a better prognosis.

Background: Mycobacterium tuberculosis (M. tuberculosis) is the causative agent of tuberculosis. As an important component of host immunity, macrophages are not only the first line of defense against M. tuberculosis but also the parasitic site of M. tuberculosis in the host. Glucocorticoids can cause immunosuppression, which is considered to be one of the major risk factors for active tuberculosis, but the mechanism is unclear. Objective: To study the effect of methylprednisolone on the proliferation of mycobacteria in macrophages and try to find key molecules of this phenomenon. Methods: The macrophage line RAW264.7 infected by M. smegmatis was treated with methylprednisolone, and the intracellular bacterial CFU, Reactive Oxygen Species (ROS), cytokine secretion, autophagy, and apoptosis were measured. After the cells were treated with NF-κB inhibitor BAY 11-7082 and DUSP1 inhibitor BCI, respectively, the intracellular bacterial CFU, ROS, IL-6, and TNF-α secretion were detected. Results: After treatment with methylprednisolone, the CFU of intracellular bacteria increased, the level of ROS decreased, and the secretion of IL-6 and TNF-α decreased in infected macrophages. After BAY 11-7082 treatment, the CFU of M. smegmatis in macrophages increased, and the level of ROS production and the secretion of IL-6 by macrophages decreased. Transcriptome high-throughput sequencing and bioinformatics analysis suggested that DUSP1 was the key molecule in the above phenomenon. Western blot analysis confirmed that the expression level of DUSP1 was increased in the infected macrophages treated with methylprednisolone and BAY 11-7082, respectively. After BCI treatment, the level of ROS produced by infected macrophages increased, and the secretion of IL-6 increased. After the treatment of BCI combined with methylprednisolone or BAY 11-7082, the level of ROS produced and the secretion of IL-6 by macrophages were increased. Conclusion: methylprednisolone promotes the proliferation of mycobacteria in macrophages by suppressing cellular ROS production and IL-6 secretion through down-regulating NF-κB and up-regulating DUSP1 expression. BCI, an inhibitor of DUSP1, can reduce the level of DUSP1 in the infected macrophages and inhibit the proliferation of intracellular mycobacteria by promoting cellular ROS production and IL-6 secretion. Therefore, BCI may become a new molecule for host-directed therapy of tuberculosis, as well as a new strategy for the prevention of tuberculosis when treated with glucocorticoids.

Amid the rapid development of nanosciences and nanotechnologies, plasmonics has emerged as an essential and fascinating discipline. Surface plasmons (SPs) lay solid physical foundations for plasmonics and have been broadly applied to ultrahigh-resolution spectroscopy, optical modulation, renewable energy, communication technology, etc. Sensitive optical characterizations for SPs, including far/near-field optics, spatial-resolved spectroscopy, and time-resolved behaviors of SPs, have prompted intense interest in diverse fields. In this Research Update, the ultrasensitive optical characterization for sub-radiant SPs is first introduced. Then, distinct characterization methods of nonlinear plasmonics, including plasmon-enhanced second harmonic generation and plasmon-enhanced sum frequency generation, are demonstrated in some classical nanostructures. Transient optical characterizations of SPs are also demonstrated in some well-defined nanostructures, enabling the deep realization of time-resolved behaviors. Finally, future prospects and efforts of optical characterization for SPs are proposed.

Abstract Due to the strong liquid intermolecular force, feasible sensing‐detection methods in liquid environments are absent. Inspired by fish swim bladder, herein, a hollow‐structured microfiber is designed to realize high‐performance sensing in liquid environments. It composes of 2D polypyrrole (2DPPy) and reduced graphene oxide (rGO), and its wall has a porous skeleton of 2DPPy/rGO/2DPPy (2DPrG2DP). The internal cavities of porous skeleton will be filled by the liquid, while leaving a bubble inside the hollow micropipe due to the liquid surface tension, thus forming a solid/liquid/gas triple‐phase interface. This hollow microfiber transforms the unmanageable liquid‐phase sensing into gas‐phase sensing. During this process, the good mechanical strength of 2DPPy enables the high sensing operability, and the reversible gas extrusion‐withdraw process enables the high sensitivity. The hollow 2DPrG2DP microfiber‐based sensor can be potentially used to machine trouble shooting, water level monitoring, ocean current monitoring, tsunami warning, body fluid and blood monitoring, and oil transportation monitoring.

The development of novel liquid-based electronics requires a new class of liquid electronic materials with combined fluidic, freestanding, and conducting properties. Here, the authors demonstrate a self-healing crystal-confined ionic liquid that shows fluidic and solid-like functionality.

The high-order harmonic generation (HHG) in ZnO is investigated by numerically solving semiconductor Bloch equations (SBEs), which can be explained well by a four-step model. In this model, preacceleration is the first step, in which the electron is accelerated in the valence band until it reaches the point of the minimum band gap. To prove the existence of the preacceleration process, SBE-based k-resolved harmonic spectra and the transient conduction-band population are presented. The results show that the contribution of crystal-momentum channels away from the minimum band gap via preacceleration is non-negligible. Furthermore, the X-shaped distribution in the k-resolved spectra can be described well by the preacceleration process. Based on the above analysis, we can conclude that the preacceleration process plays an important role in HHG.

Summary: Effective thermal regulation has shown great impacts on tremendous aspects of our life and manufacture. However, the invisible nature of thermal field brings us inconvenience or even security hazard. Herein, we present a method to visualize thermal distribution with the aid of a thermally active material. An ionic liquid with lower critical solution temperature is mixed within hydrogel to demonstrate a hydrogel confined ionic system (HCIS). This particular system turns turbid as the temperature exceeds an established temperature threshold, which is adjustable through applying different concentrations of HCl or NaCl. The system offers straightforward images of the spatial thermal distribution whether simple or sophisticated, which is fully in line with computational simulation. The system is further demonstrated with great promise for the application in fire warning to lower the threat induced by electrical failure. The HCIS opens a practical avenue to visualize thermal distribution and improve our thermal regulation efficiency.

Bamboo shoot, the young culms of bamboo plants, has been utilized as a food item in Asian countries. Bamboo shoots are rich in protein, fiber, vitamins and minerals as well as plenty of nutraceuticals including phenols and phytosterols. Bamboo shoots were historically used in medications and recently identified with the diverse health benefits such as hypolipidemic, prebiotic and anti-diabetic activities. However, the rapid postharvest lignification deteriorated the nutritional quality and palatability of fresh bamboo shoots, and the presence of cyanogenic glycosides made them inapplicable being eaten raw. To these ends, physical and chemical regimes were invented for their postharvest storage and various processing methods were adopted to eliminate the toxins and achieve a year-round supply. With their consumption spreading over the continents, bamboo shoots become more important in human diet. The sustainable development, food safety control and the clarification of their potential health effects are suggested in future consideration.

This study revealed the underlying mechanisms involved in the puffing process of dried cassava starch gel by exploring the development of the puffed structure of gel upon sand-frying, chiefly focused on the changes in the multi-scale structure and the physicochemical properties of starch. The results suggested that the sand-frying-induced puffing proceeded very fast, completed in about twenty seconds, which could be described as a two-phase pattern including the warming up (0~6 s) and puffing (7~18 s) stages. In the first stage, no significant changes occurred to the structure or appearance of the starch gel. In the second stage, the cells in the gel network structure were expanded until burst, which brought about a decrease in moisture content, bulk density, and hardness, as well as the increase in porosity and crispness when the surface temperature of gel reached glass transition temperature of 125.28 °C. Upon sand-frying puffing, the crystalline melting and molecular degradation of starch happened simultaneously, of which the latter mainly occurred in the first stage. Along with the increase of puffing time, the thermal stability, peak viscosity, and final viscosity of starch gradually decreased, while the water solubility index increased. Knowing the underlying mechanisms of this process might help manufacturers produce a better quality of starch-based puffed products.

Photothermal therapy has aroused great attention and showed promising potential in minimally invasive tumor ablation, but the clinical translation is still stifled by the concerns of unwanted injury to normal tissues. The safety concerns might be completely solved only when the two security obstacles of "material-toxicity" and "photo-toxicity" were overcome simultaneously. Herein, a completely non-toxic food-grade photothermal transduction agent (PTA) with double safety guarantees was invented, which shows an absolute transformation of the photothermal effect from "0" to "1" after being triggered by an acidic tumor microenvironment. Inspired by the classical starch-iodine test, a preprogrammed [starch-KI-KIO3] complex was prepared in large quantities through a modified wet-milling procedure. It's demonstrated that a macroscopic consecutive reaction could be triggered by low pH to produce the starch-iodine complex which can generate lethal temperature under the near-infrared light irradiation. Meanwhile, the PTA shows excellent biocompatibility with no "material-toxicity" owing to the raw materials drawn from our daily food. Animal experiments reveal that the tumor microenvironment can activate the switch of photothermal effect from "0" to "1" successfully, which is thus responsible for the discriminative photo-damage to the tumor region while no "photo-toxicity" to normal tissue. The good treatment efficacy confirms the feasibility of such photothermal transduction agents with double safety guarantees in clinical applications. [ABSTRACT FROM AUTHOR]