Human Virus-Derived Small RNAs Can Confer Antiviral Immunity in Mammals.

RNA interference (RNAi) functions as a potent antiviral immunity in plants and invertebrates; however, whether RNAi plays antiviral roles in mammals remains unclear. Here, using human enterovirus 71 (HEV71) as a model, we showed HEV71 3A protein as an authentic viral suppressor of RNAi during viral infection. When the 3A-mediated RNAi suppression was impaired, the mutant HEV71 readily triggered the production of abundant HEV71-derived small RNAs with canonical siRNA properties in cells and mice. These virus-derived siRNAs were produced from viral dsRNA replicative intermediates in a Dicer-dependent manner and loaded into AGO, and they were fully active in degrading cognate viral RNAs. Recombinant HEV71 deficient in 3A-mediated RNAi suppression was significantly restricted in human somatic cells and mice, whereas Dicer deficiency rescued HEV71 infection independently of type I interferon response. Thus, RNAi can function as an antiviral immunity, which is induced and suppressed by a human virus, in mammals.

K64 acetylation of heat shock protein 90 suppresses nucleopolyhedrovirus replication in Bombyx mori.

HSP90 is a highly conserved chaperone that facilitates the proliferation of many viruses, including silkworm (bombyx mori) nucleopolyhedrovirus (BmNPV), but the underlying regulatory mechanism was unclear. We found that suppression of HSP90 by 17-AAG, a HSP90-specific inhibitor, significantly reduced the expression of BmNPV capsid protein gp64 and viral genome replication, whereas overexpression of B. mori HSP90(BmHSP90) promoted BmNPV replication. Furthermore, in a recent study of the lysine acetylome of B. mori infected with BmNPV, we focused on the reduced viral proliferation due to changes of BmHSP90 lysine acetylation. Site-directed introduction of acetylated (K/Q) or deacetylated (K/R) mimic mutations into BmHSP90 revealed that lysine 64 (K64) acetylation activated the JAK/STAT pathway and reduced BmHSP90 ATPase activity, leading to diminished chaperone activity and ultimately inhibiting BmNPV proliferation. In this study, a single lysine 64 acetylation change of BmHSP90 was elucidated as a model of posttranslational modifications occurring in the wake of host-virus interactions, providing novel insights into potential antiviral strategies.

Cloning and characterization of the histone variant gene H2A.Z in Bombyx mori.

H2A.Z, the most evolutionarily conserved variant of histone H2A, plays a pivotal role in chromatin remodeling and contributes significantly to gene transcription and genome stability. However, the role of H2A.Z in the silkworm (Bombyx mori) remains unclear. In this study, we cloned the BmH2A.Z from B. mori. The open reading frame of BmH2A.Z is 390 bp, encoding 129 amino acids, with a confirmed molecular weight of 13.4 kDa through prokaryotic expression analysis. Sequence analysis revealed that BmH2A.Z has a conserved H2A.Z domain and is closely related to the systemic evolution of other known H2A.Zs. The expression profile of BmH2A.Z at various developmental stages of the B. mori exhibited the highest expression level in the 1st instar, followed by the grain stage and the 2nd instar, and the lowest expression level in the moth. The highest transcript level of BmH2A.Z was observed in the head, with relatively lower levels detected in the blood than in the other tissues under consideration. In addition, the upregulation of BmH2A.Z resulted in the amplified expression of B. mori nucleopolyhedrovirus (BmNPV) genes, thus facilitating the proliferation of BmNPV. This study establishes a foundation for investigating the role of BmH2A.Z in B. mori and its participation in virus-host interactions.

Gorham-Stout disease affecting the spine with cerebrospinal fluid leakage and Chiari-like tonsillar herniation: a rare case report and review of literature.

BACKGROUND: Gorham-Stout disease (GSD) is a very rare disorder characterized by massive osteolysis of poorly understood aetiology. The association between GSD involving the skull base and cerebrospinal fluid (CSF) leakage has been reported in the literature. However, few cases of CSF leakage and Chiari-like tonsillar herniation in GSD involving the spine have been reported. CASE PRESENTATION: We present the case of a 20-year-old man with GSD involving the thoracic and lumbar spine, which caused CSF leakage and Chiari-like tonsillar herniation. The patient underwent four spinal surgeries for osteolytic lesions of the spine over a 10-year period. Here, we discuss the possible aetiology of the development of CSF leakage. Epidural blood patch (EBP) was performed at the T11-T12 level to repair the CSF leakage. After EBP treatment, rebound intracranial hypertension (RIH) developed, and tonsillar herniation disappeared 2 months later. CONCLUSIONS: GSD involving the spine with CSF leakage and Chiari-like tonsillar herniation is relatively rare. For patients who have undergone multiple spinal surgeries, minimally invasive treatment is an alternative treatment for CSF leakage. EBP can repair CSF leakage secondary to GSD and improve chronic brain sagging, with reversibility of Chiari-like malformations.

Effects of LEF-11 acetylation modification on the regulation of baculovirus infection.

Late expression factor 11 (LEF-11) is an essential protein in the regulation of Bombyx mori nucleopolyhedrovirus (BmNPV) DNA replication and late gene expression. Our recent quantitative analysis of protein acetylome revealed for the first time that LEF-11 can be acetylated at one lysine residue (K83) during viral infection, but the underlying mechanism is unclear. The acetylation level for K83 was down-regulated after 36 h post-infection by approximately 30%. To clarify the regulatory function of this modification, overlap PCR was used for site-specific mutagenesis for acetylated (K83Q) or deacetylated (K83R) mimic mutants of LEF-11. The results of viral titration and quantitative polymerase chain reaction showed that after K83 acetylation, budding virion production and the viral genome replication level were significantly upregulated. Meanwhile, the results of yeast two-hybrid (Y2H) system confirmed that K83 deacetylation modification inhibited the interaction between LEF-11 and immediate early gene 1 (IE-1). In conclusion, the acetylation of LEF-11 at K83 might enhance the interaction with IE-1 in the host cell nucleus to promote viral DNA replication, and might be one of the antiviral strategies of the silkworm host. The host inhibits virus proliferation by deacetylating LEF-11. Keywords: BmNPV; LEF-11; acetylation; virus replication; protein interaction.

Acetylation of citrate synthase inhibits Bombyx mori nucleopolyhedrovirus propagation by affecting energy metabolism.

Many studies have confirmed that virus infection cause changes in the expression level and post-translational modifications of tricarboxylic acid cycle (TCA) enzymes. In a previous study, we found that the acetylation level of lysine 336 of Bombyx mori citrate synthase (BmCS) was remarkably unregulated after Bombyx mori nucleopolyhedrovirus (BmNPV) infection. In the present study, we found that BmN cells infected with BmNPV could up-regulate BmCS transient expression and promote the acetylation modification of BmCS. Transient expression vectors for over-expression of wild-type Bmcs and K336 acetylation mimic mutant (K336Q) were constructed to analyze enzyme activity, revealing that acetylation of K336 significantly reduced its activity. The obtained results indicated that BmCS knock-down or K336 acetylation similarly suppressed BmN cellular ATP production and mitochondrial membrane potential. Furthermore, the acetylation of K336 and the reduction of BmCS expression contributed to weakening the replication lever of the BmNPV proliferation and the generation of progeny viruses. In sum, our study on the single lysine 336 acetylation and knock-down of Bmcs revealed the potential mechanism for inhibiting the proliferation of BmNPV, which may provide novel insights for the development of antiviral strategies.

Acetylation of fructose-bisphosphate aldolase-mediated glycolysis is essential for Bombyx mori nucleopolyhedrovirus infection.

Bombyx mori nucleopolyhedrovirus (BmNPV) is a baculovirus that infects silkworms, and its interaction with silkworm has been considered an important model in the field of insect virology. Accumulating evidence indicates that most viruses promote glycolytic metabolism in host cells to favor infection. However, similar reports are lacking in insects, especially in the area of post-translational modifications of proteins. In this study, we found that BmNPV infection induced the acetylation of fructose-bisphosphate aldolase (ALDO) on lysine 42 (K42) to promote its enzyme activity. To explore the underlying mechanisms, site-directed mutagenesis of deacetylated mimic (K/R) was performed. The results demonstrated that K42 acetylation promoted viral proliferation by exacerbating the glycolytic flux induced by BmNPV infection, which resulted in increased ATP, glucose uptake and lactate accumulation. Inhibiting glycolysis with 2-deoxygucose (2DG) revealed that glycolysis was essential for optimal BmNPV infection. Finally, we showed that BmNPV-infected cells enhanced the transcription of glycolysis-related genes, including Glut1, Hk2 and Ldh. In parallel, K42 acetylation of ALDO also promoted the expression of these genes. Therefore, acetylation of ALDO could be considered a regulator of BmNPV-induced glycolysis. These finding provide insights into the interaction between silkworm and BmNPV.

Experimental Study on the Rupture Behavior of the Liquid Bridge between Three Rigid Spheres.

The powder process is dynamic at the microscale level. Due to the capillary effect, the viscous attraction of the liquid phase between particles alters the strength and stability of wet granular materials. In this paper, experiments on the rupture behavior of the funicular liquid bridge between three rigid spheres have been presented. The results show that the peak force and rupture distance of the funicular liquid bridges are affected by the size and relative position of the spheres, volume and viscosity of the liquid, and separation rate; the coalescence of the liquid bridges causes a decrease in peak force and an increase in rupture distance, and the rupture distance shows a nonmonotonic functional correlation with the separation rate. Finally, an empirical equation of the correlation between the rupture distance and liquid volume is proposed, whose rationality is verified by comparing it with the results of the existing models.

Integrative Analysis of Expression Profiles of mRNA and MicroRNA Provides Insights of Cotton Response to Verticillium dahliae.

Cotton Verticillium wilt, caused by the notorious fungal phytopathogen Verticillium dahliae (V. dahliae), is a destructive soil-borne vascular disease and severely decreases cotton yield and quality worldwide. Transcriptional and post-transcriptional regulation of genes responsive to V. dahliae are crucial for V. dahliae tolerance in plants. However, the specific microRNAs (miRNAs) and the miRNA/target gene crosstalk involved in cotton resistance to Verticillium wilt remain largely limited. To investigate the roles of regulatory RNAs under V. dahliae induction in upland cotton, mRNA and small RNA libraries were constructed from mocked and infected roots of two upland cotton cultivars with the V. dahliae-sensitive cultivar Jimian 11 (J11) and the V. dahliae-tolerant cultivar Zhongzhimian 2 (Z2). A comparative transcriptome analysis revealed 8330 transcripts were differentially expressed under V. dahliae stress and associated with several specific biological processes. Moreover, small RNA sequencing identified a total of 383 miRNAs, including 330 unique conserved miRNAs and 53 novel miRNAs. Analysis of the regulatory network involved in the response to V. dahliae stress revealed 31 differentially expressed miRNA−mRNA pairs, and the up-regulation of GhmiR395 and down-regulation of GhmiR165 were possibly involved in the response to V. dahliae by regulating sulfur assimilation through the GhmiR395-APS1/3 module and the establishment of the vascular pattern and secondary cell wall formation through GhmiR165-REV module, respectively. The integrative analysis of mRNA and miRNA expression profiles from upland cotton lays the foundation for further investigation of regulatory mechanisms of resistance to Verticillium wilt in cotton and other crops.

Cloning and characterization of the MYB transcription factor gene GhTT2 in Gossypium hirsutum.

As one of the important secondary metabolites, proanthocyanidins (PAs) are not only a defense mechanism for plants to cope with biotic and abiotic stresses, but also a key factor affecting the development and quality of plants. Although the biosynthetic and metabolic pathways of proanthocyanidins have been basically clarified in the model plants, the regulatory mechanism in cotton has not been fully elucidated. In this work, a transcription factor gene GhTT2 (transparent testa 2) was cloned from Gossypium hirsutum. Its gene structure, expression pattern, subcellular localization, and function were further analyzed. The results show that the GhTT2 has a typical MYB domain and is predominantly expressed in fibers. Its transcription level was negatively correlated with anthocyanin content. The GhTT2-GFP fusion protein is located in the nucleus. Moreover, yeast transformation results show that GhTT2 has obvious transcriptional activation characteristics. Furthermore, the content of proanthocyanidins in GhTT2-silenced cottons is significantly reduced, indicating that GhTT2 may be involved in regulation of the proanthocyanidins biosynthesis in Gossypium hirsutum. These results provide a reference for further elucidating the molecular mechanisms of MYB transcription factors involved in the regulation of the biosynthetic pathway of PAs.

Role of the Bombyx mori nucleopolyhedrovirus LEF3 acetylation on viral replication.

Late expression factor 3 (LEF3) is a single-stranded DNA binding protein of Bombyx mori nucleopolyhedrovirus (BmNPV) with multiple functions. It is an essential factor for viral DNA replication and plays an important regulatory role during BmNPV infection. Our recent quantitative analysis of protein acetylome revealed for the first time that LEF3 can be acetylated at four lysine residues during the viral infection, but the underlying mechanism is unknown. Among the modification sites, two of them (K18 and K27) are located in the conserved nuclear localization sequence region. The acetylation level for K18 especially was up-regulated approximately 7.4 times after 36 h of post-infection. To understand the regulatory function of this modification, site-direct mutagenesis for acetylated mimic (K18Q) or deacetylated mimic (K18R) mutants was performed on LEF3. The fluorescence analysis results showed that the replication capacity of the virus was significantly reduced after K18 acetylation. Meanwhile, co-localization analysis revealed that acetylation at K18 caused LEF3 to lose its nuclear targeting ability and affected the interaction between LEF3 and P143, retaining P143 in the cytoplasm. And further Yeast two-hybrid analysis results also confirmed that the acetylation at K18 did affect the interaction between LEF3 and P143. In conclusion, the acetylation of LEF3 at K18 might act as one of the antiviral strategies for silkworm host by affecting nuclear localization of LEF3, interaction with P143, and then blocking viral replication.

HSP/HSC70 activity is required for Bombyx mori nucleopolyhedrovirus replication at the early infectious phase.

Bombyx mori nucleopolyhedrovirus caused large amounts of silk loss annually, although it also could be used as silkworm bioreactor expression vector effectively and efficiently. Many heat shock (cognate) proteins 70 (HSP/HSC70) were induced by baculovirus and found existence in viral structure assembly. However, the concrete mechanism still need further elucidation for understanding host and virus interaction. In this study, the application of HSP/HSC70 inhibitor VER155008 is virus infectious phase-dependent for figuring out the role of intact molecular chaperone HSP/HSC70 activity in different stages of BmNPV proliferation progress. All the data had shown that HSP/HSC70 played a vital role in viral genome replication, virus protein abundance, BmNPV proliferation and budded virus production at the early infectious phase. This finding may provide new insights to unravel the interaction between baculovirus and silkworm in the initial infectious stage.

Light Runs Across Iron Catalysts in Organic Transformations.

Over the past decades, organometallic complexes with precious elements, such as ruthenium and iridium, are widely used as visible-light photoredox catalysts. Recently, more and more complexes based on earth-abundant and inexpensive elements have been used as sensitizers in photochemistry. Although the photoexcited state lifetimes of iron complexes are typically shorter than those of traditional photosensitizers, the utilization of iron catalysts in photochemistry has sprung up owing to their abundance, low price, nontoxicity, and novel properties, including exhibiting ligand to metal charge transfer states. This concept focuses on recent advances in light-driven iron catalysis in organic transformations, including iron/photoredox dual catalysis, light-induced iron photoredox catalysis and light-induced generation of active iron catalysts. The prospect for the future of this field is also discussed.

Spray-inlet microwave plasma torch ionization tandem mass spectrometry for the direct detection of drug samples in liquid solutions.

RATIONALE: Drug abuse or dependence results in a series of social problems, including crime and traffic accidents. Spray-inlet microwave plasma torch tandem mass spectrometry (MPT-MS/MS) was developed and used for the direct detection of such drugs in liquid solutions. METHODS: Drug sample solutions were directly sprayed into the flame of an MPT by a sampling pump and the ions produced by Penning ionization and ion-molecule reactions were guided into a quadrupole time-of-flight (QTOF) tandem mass spectrometer for mass analysis. The MPT was operated at 40 W and 2.45 GHz in a 700 mL/min argon flow both for the inner and middle plasma. RESULTS: Intact quasi-molecular and molecular ions of various drugs were successfully characterized by spray-inlet MPT-MS/MS. The analysis of one sample was finished within 30 s. Furthermore, the method exhibited excellent efficiency, precision and sensitivity, and the limits of detection and limits of quantification of the samples in methanol were in the range of 5.25-60.0 and 17.5-200 ng g-1 , respectively. Excellent linearities with coefficients of determination (R2 ) of 0.9627-0.9980 were verified in the range 0.05-50 µg g-1 . Four different beverages purchased locally were also analyzed with spray-inlet MPT-MS/MS, and caffeine was directly determined in two of the beverages. By adding six standard drug samples to sport drinks (each drug was 1 µg g-1 ) and Chinese spirit (each drug was 0.1 µg g-1 ), all the drugs except for caffeine were detected successfully. CONCLUSIONS: This study indicates that spay-inlet MPT-MS/MS is an effective method for direct and rapid identification of drug solutions, and it has substantial potential for fast and sensitive drug residue detection.

Visible-Light-Driven Iron-Promoted Thiocarboxylation of Styrenes and Acrylates with CO2.

The first thiocarboxylation of styrenes and acrylates with CO2 was realized by using visible light as a driving force and catalytic iron salts as promoters. A variety of important ß-thioacids were obtained in high yields. This multicomponent reaction proceeds in an atom- and redox-economical manner with broad substrate scope under mild reaction conditions. Notably, high regio-, chemo-, and diasteroselectivity are observed. Mechanistic studies indicate that a radical pathway can account for the unusual regioselectivity.

Programming Effects of Prenatal Glucocorticoid Exposure with a Postnatal High-Fat Diet in Diabetes Mellitus.

Increasing evidence has shown that many chronic diseases originate from early life, even before birth, through what are termed as fetal programming effects. Glucocorticoids are frequently used prenatally to accelerate the maturation of the lungs of premature infants. High-fat diets are associated with insulin resistance, but the effects of prenatal glucocorticoid exposure plus a postnatal high-fat diet in diabetes mellitus remain unclear. We administered pregnant Sprague-Dawley rats' intraperitoneal dexamethasone (0.1 mg/kg body weight) or vehicle at gestational days 14-20. Male offspring were administered a normal or high-fat diet starting from weaning. We assessed the effects of prenatal steroid exposure plus postnatal high-fat diet on the liver, pancreas, muscle and fat at postnatal day 120. At 15 and 30 min, sugar levels were higher in the dexamethasone plus high-fat diet (DHF) group than the vehicle plus high-fat diet (VHF) group in the intraperitoneal glucose tolerance test (IPGTT). Serum insulin levels at 15, 30 and 60 min were significantly higher in the VHF group than in the vehicle and normal diet group. Liver insulin receptor and adenosine monophosphate-activated protein kinase mRNA expressions and protein levels were lower in the DHF group. Insulin receptor and insulin receptor substrate-1 mRNA expressions were lower in the epididymal adipose tissue in the VHF and DHF groups. "Programming" of liver or epididymal adipose tissue resulted from prenatal events. Prenatal steroid exposure worsened insulin resistance in animals fed a high-fat diet.

The Ti4 cluster activates water dissociation on defective graphene.

Activation of the Ti4 cluster on defective graphene for water adsorption and dissociation was investigated via density functional theory. Both the vacancy and the Ti cluster can promote the water dissociation reaction. The vacancy can efficiently enhance the adsorption of Ti atoms to stabilize the cluster. However, compared to the role of the vacancy, the cluster plays a more important role in activating water dissociation. A single water molecule and a second one can almost freely dissociate with (or without) a low barrier on the Ti4 cluster, the barriers are substantially lower than that on a single Ti atom. The Ti4 cluster decorated graphene is a promising candidate for activation of the dissociation of water molecules.

Cross-modal missing time-series imputation using dense spatio-temporal transformer nets.

Due to irregular sampling or device failure, the data collected from sensor network has missing value, that is, missing time-series data occurs. To address this issue, many methods have been proposed to impute random or non-random missing data. However, the imputation accuracy of these methods are not accurate enough to be applied, especially in the case of complete data missing (CDM). Thus, we propose a cross-modal method to impute time-series missing data by dense spatio-temporal transformer nets (DSTTN). This model embeds spatial modal data into time-series data by stacked spatio-temporal transformer blocks and deployment of dense connections. It adopts cross-modal constraints, a graph Laplacian regularization term, to optimize model parameters. When the model is trained, it recovers missing data finally by an end-to-end imputation pipeline. Various baseline models are compared by sufficient experiments. Based on the experimental results, it is verified that DSTTN achieves state-of-the-art imputation performance in the cases of random and non-random missing. Especially, the proposed method provides a new solution to the CDM problem.

Metal-Free Nitrogen-Doped Mesoporous Carbons for the Mild and Selective Synthesis of Pyrroles from Nitroarenes via Cascade Reaction.

The cascade synthesis of pyrroles from nitroarenes is an attractive alternative strategy. However, metal catalysts and relatively high temperatures cover the existing reported catalytic systems for this strategy. The development of nonmetallic heterogeneous catalytic systems for the one-pot synthesis of pyrrole from nitroarenes under mild conditions is both worthwhile and challenging. Herein, we describe an exceptionally efficient method for the synthesis of N-substituted pyrroles by the reductive coupling of nitroarenes and diketones over heterogeneous metal-free catalysts under mild conditions. Nonmetallic NC-X catalysts with high activity were prepared from the pyrolysis of well-defined ligands via simple sacrificing hard template methods. Hydrazine hydrate, formic acid, and molecular hydrogen can all be used as reducing agents in the hydrogenation/Paal-Knorr reaction sequence to efficiently synthesize various N-substituted pyrroles, including drugs and bioactive molecules. The catalytic system was featured with good tolerance to sensitive functional groups and no side reactions such as dehalogenation and aromatics hydrogenation. Hammett correlation studies have shown that the electron-donating substituents are beneficial for the one-pot synthesis of N-substituted pyrroles. The results established that the outstanding performance of the catalyst is mainly attributed to the contribution of graphitic N in the catalyst as well as the promotion effect of the mesoporous structure on the reaction.