Host-pathogen interaction between pitaya and Neoscytalidium dimidiatum reveals the mechanisms of immune response associated with defense regulators and metabolic pathways.

BACKGROUND: Understanding how plants and pathogens regulate each other's gene expression during their interactions is key to revealing the mechanisms of disease resistance and controlling the development of pathogens. Despite extensive studies on the molecular and genetic basis of plant immunity against pathogens, the influence of pitaya immunity on N. dimidiatum metabolism to restrict pathogen growth is poorly understood, and how N. dimidiatum breaks through pitaya defenses. In this study, we used the RNA-seq method to assess the expression profiles of pitaya and N. dimidiatum at 4 time periods after interactions to capture the early effects of N. dimidiatum on pitaya processes. RESULTS: The study defined the establishment of an effective method for analyzing transcriptome interactions between pitaya and N. dimidiatum and to obtain global expression profiles. We identified gene expression clusters in both the host pitaya and the pathogen N. dimidiatum. The analysis showed that numerous differentially expressed genes (DEGs) involved in the recognition and defense of pitaya against N. dimidiatum, as well as N. dimidiatum's evasion of recognition and inhibition of pitaya. The major functional groups identified by GO and KEGG enrichment were responsible for plant and pathogen recognition, phytohormone signaling (such as salicylic acid, abscisic acid). Furthermore, the gene expression of 13 candidate genes involved in phytopathogen recognition, phytohormone receptors, and the plant resistance gene (PG), as well as 7 effector genes of N. dimidiatum, including glycoside hydrolases, pectinase, and putative genes, were validated by qPCR. By focusing on gene expression changes during interactions between pitaya and N. dimidiatum, we were able to observe the infection of N. dimidiatum and its effects on the expression of various defense components and host immune receptors. CONCLUSION: Our data show that various regulators of the immune response are modified during interactions between pitaya and N. dimidiatum. Furthermore, the activation and repression of these genes are temporally coordinated. These findings provide a framework for better understanding the pathogenicity of N. dimidiatum and its role as an opportunistic pathogen. This offers the potential for a more effective defense against N. dimidiatum.

Federated Discriminative Representation Learning for Image Classification.

Acquiring big-size datasets to raise the performance of deep models has become one of the most critical problems in representation learning (RL) techniques, which is the core potential of the emerging paradigm of federated learning (FL). However, most current FL models concentrate on seeking an identical model for isolated clients and thus fail to make full use of the data specificity between clients. To enhance the classification performance of each client, this study introduces the FDRL, a federated discriminative RL model, by partitioning the data features of each client into a global subspace and a local subspace. More specifically, FDRL learns the global representation for federated communication between those isolated clients, which is to capture common features from all protected datasets via model sharing, and local representations for personalization in each client, which is to preserve specific features of clients via model differentiating. Toward this goal, FDRL in each client trains a shared submodel for federated communication and, meanwhile, a not-shared submodel for locality preservation, in which the two models partition client-feature space by maximizing their differences, followed by a linear model fed with combined features for image classification. The proposed model is implemented with neural networks and optimized in an iterative manner between the server of computing the global model and the clients of learning the local classifiers. Thanks to the powerful capability of local feature preservation, FDRL leads to more discriminative data representations than the compared FL models. Experimental results on public datasets demonstrate that our FDRL benefits from the subspace partition and achieves better performance on federated image classification than the state-of-the-art FL models.

Gas Chromatography-Mass Spectrometry Reveals Stage-Specific Metabolic Signatures of Ankylosing Spondylitis.

Ankylosing spondylitis (AS) is a type of chronic rheumatic immune disease, and the crucial point of AS treatment is identifying the correct stage of the disease. However, there is a lack of effective diagnostic methods for AS staging. The primary objective of this study was to perform an untargeted metabolomic approach in AS patients in an effort to reveal metabolic differences between patients in remission and acute stages. Serum samples from 40 controls and 57 AS patients were analyzed via gas chromatography-mass spectrometry (GC-MS). Twenty-four kinds of differential metabolites were identified between the healthy controls and AS patients, mainly involving valine/leucine/isoleucine biosynthesis and degradation, phenylalanine/tyrosine/tryptophan biosynthesis, glutathione metabolism, etc. Furthermore, the levels of fatty acids (linoleate, dodecanoate, hexadecanoate, and octadecanoate), amino acids (serine and pyroglutamate), 2-hydroxybutanoate, glucose, etc., were lower in patients in the acute stage than those in the remission stage, which may be associated with the aggravated inflammatory response and elevated oxidative stress in the acute stage. Multiple stage-specific metabolites were significantly correlated with inflammatory indicators (CRP and ESR). In addition, the combination of serum 2-hydroxybutanoate and hexadecanoate plays a significant role in the diagnosis of AS stages. These metabolomics-based findings provide new perspectives for AS staging, treatment, and pathogenesis studies.

Antimicrobial peptide temporin derivatives inhibit biofilm formation and virulence factor expression of Streptococcus mutans.

Introduction: Temporin-GHa obtained from the frog Hylarana guentheri showed bactericidal efficacy against Streptococcus mutans. To enhance its antibacterial activity, the derived peptides GHaR and GHa11R were designed, and their antibacterial performance, antibiofilm efficacy and potential in the inhibition of dental caries were evaluated. Methods: Bacterial survival assay, fluorescent staining assay and transmission electron microscopy observation were applied to explore how the peptides inhibited and killed S. mutans. The antibiofilm efficacy was assayed by examining exopolysaccharide (EPS) and lactic acid production, bacterial adhesion and cell surface hydrophobicity. The gene expression level of virulence factors of S. mutans was detected by qRT-PCR. Finally, the impact of the peptides on the caries induced ability of S. mutans was measured using a rat caries model. Results: It has been shown that the peptides inhibited biofilm rapid accumulation by weakening the initial adhesion of S. mutans and reducing the production of EPS. Meanwhile, they also decreased bacterial acidogenicity and aciduricity, and ultimately prevented caries development in vivo. Conclusion: GHaR and GHa11R might be promising candidates for controlling S. mutans infections.

The Pitaya Flower Tissue's Gene Differential Expression Analysis between Self-Incompatible and Self-Compatible Varieties for the Identification of Genes Involved in Self-Incompatibility Regulation.

Self-incompatible pitaya varieties have low fruit-setting rates under natural conditions, leading to higher production costs and hindering industrial prosperity. Through transcriptome sequencing, we obtained the 36,900 longest transcripts (including 9167 new transcripts) from 60 samples of flowers. Samples were collected pre- and post-pollination (at 0 h, 0.5 h, 2 h, 4 h, and 12 h) from two varieties of pitaya (self-compatible Jindu No. 1 and self-incompatible Cu Sha). Using the RNA-Seq data and comparison of reference genomes, we annotated 28,817 genes in various databases, and 1740 genes were optimized in their structure for annotation. There were significant differences in the expression of differentially expressed genes (DEGs) in the pitaya stigmas under different pollination types, especially at the late post-pollination stage, where the expression of protease genes increasedal significantly under cross-pollination. We identified DEGs involved in the ribosomal, ubiquitination-mediated, and phyto-signaling pathways that may be involved in pitaya SI regulation. Based on the available transcriptome data and bioinformatics analysis, we tentatively identified HuS-RNase2 as a candidate gynogenetic S gene in the pitaya GSI system.

Droplet Microfluidic-Based Low-Cost and High-Speed Microsphere Array Direct Writing Technology and Its Applications.

Microsphere arrays have significant applications and broad development prospects in various fields and disciplines. The simple, efficient, low-cost, automatic, and controllable preparation of microsphere arrays in multiple dimensions and morphologies is still a significant challenge. Here, a novel microsphere array direct writing technology was developed using a low-cost portable droplet microfluidic device and a high-precision XY movable platform. The proposed technology provided a powerful platform for the direct-writing preparation of microsphere arrays and was successfully applied to the precise and controllable fabrication of microsphere arrays with different sizes, shapes, structures, and arrangements. Additionally, gel microsphere arrays with metal ion patterns were fabricated using the microsphere arrays as templates and exhibited excellent performance in the visual analytical detection of heavy metal ions. Moreover, the simulated microsphere arrays offer a promising platform for rapidly generating high-viability and uniform 3D tumor spheroids. Therefore, given the superiority of this technology and the great potential of microsphere arrays, this simple high-speed microsphere array direct writing technology has a promising application in the multidisciplinary intersection of chemical, biological, and material sciences.

The role of fibronectin in multiple sclerosis and the effect of drug delivery across the blood-brain barrier.

Remyelination failure is one of the main characteristics of multiple sclerosis and is potentially correlated with disease progression. Previous research has shown that the extracellular matrix is associated with remyelination failure because remodeling of the matrix often fails in both chronic and progressive multiple sclerosis. Fibronectin aggregates are assembled and persistently exist in chronic multiple sclerosis, thus inhibiting remyelination. Although many advances have been made in the mechanisms and treatment of multiple sclerosis, it remains very difficult for drugs to reach pathological brain tissues; this is due to the complexity of brain structure and function, especially the existence of the blood-brain barrier. Therefore, herein, we review the effects of fibronectin aggregates on multiple sclerosis and the efficacy of different forms of drug delivery across the blood-brain barrier in the treatment of this disease.

Temporin-GHb-Derived Peptides Exhibit Potent Antibacterial and Antibiofilm Activities against Staphylococcus aureus In Vitro and Protect Mice from Acute Infectious Pneumonia.

With the continuous development of drug resistance in bacteria to traditional antibiotics, the demand for novel antibacterial agents is urgent. Antimicrobial peptides (AMPs) are promising candidates because of their unique mechanism of action and low tendency to induce drug resistance. Previously, we cloned temporin-GHb (hereafter referred to simply as "GHb") from Hylarana guentheri. In this study, a series of derived peptides were designed, namely, GHbR, GHbK, GHb3K, GHb11K, and GHbK4R. The five derived peptides had stronger antibacterial activities against Staphylococcus aureus than the parent peptide GHb and could effectively inhibit the formation of biofilms and eradicate mature biofilms in vitro. GHbR, GHbK, GHb3K, and GHbK4R exerted bactericidal effects by disrupting membrane integrity. However, GHb11K exhibited bacteriostatic efficacy with toroidal pore formation on the cell membrane. In comparison to GHbK4R, GHb3K showed much lower cytotoxicity against A549 alveolar epithelial cells, with an IC50 > 200 µM, which was much higher than its minimal inhibitory concentration (MIC = 3.1 µM) against S. aureus. The anti-infection potential of GHbK4R and GHb3K was investigated in vivo. Compared with vancomycin, the two peptides displayed significant efficacy in a mouse model of acute pneumonia infected with S. aureus. Both GHbK4R and GHb3K also had no obvious toxicity to normal mice after intraperitoneal administration (15 mg/kg) for 8 days. Our results indicate that GHb3K and GHbK4R might be promising candidates for the treatment of bacterial pneumonia infected with S. aureus.

Molecular integrative study on interaction domains of nuclear factor erythroid 2-related factor 2 with sirtuin 6.

Oxidative stress is one of the elements causing aging and related diseases. Inhibiting Nrf2 activity or increasing oxidative pressure can replicate the deficits of premature aging. SIRT6 is one of the few proteins that can regulate both life span and aging. Deletion of SIRT6 in human cells impairs the antioxidant capacity of cells, which results in the accumulation of intracellular reactive oxygen species and DNA oxidation products. Characterization of the binding of Nrf2 with SIRT6 is critical for understanding the modulation of Nrf2-correlated cell activities by SIRT6. The yeast two-hybrid experiments showed that the binding of Nrf2 with SIRT6 is mediated by Neh1 and Neh3 domains. The elimination of the Neh1 and Neh3 domains decreased the binding stability and free energy, according to the molecular dynamic analysis. The roles of theses domains in mediating the binding were confirmed by co-immunoprecipitation. In cells transfected with the small interfering RNA (siRNA) targeting the Nrf2 Neh1 domain and plasmids overexpressing domain-mutant Nrf2, it was discovered that Nrf2 lost its activity to stimulate the transcription of antioxidant genes in the absence of Neh1 and Neh3 domains.

A Temporin Derived Peptide Showing Antibacterial and Antibiofilm Activities against Staphylococcus aureus.

BACKGROUND: Temporin is one family of the shortest antimicrobial peptides found in Ranidae frogs. Staphylococcus aureus is one of the main pathogens of suppurative diseases and food contamination, causing severe local or systemic infections in humans. Temporin-GHa (GHa) was previously obtained from Hylarana guentheri, showing weak antibacterial activity against S. aureus. Most temporin peptides are positively charged by arginine and lysine; however, GHa contains histidine. OBJECTIVE: In order to investigate the impact of positively charged amino acid on its antibacterial and antibiofilm activity, GHa4R was designed and synthesized by replacing histidine with arginine in GHa. METHODS: The antibacterial activity and efficacy against S. aureus were detected by minimum inhibitory concentration, minimum bactericidal concentration, and time-killing kinetics assays. The action mechanism was determined by propidium iodide uptake and scanning electron microscopy assays. The antibiofilm activity was measured by the MTT method. Eradication of biofilm was observed by fluorescence microscope. RESULTS: Compared to GHa, GHa4R had stronger antibacterial activity and bactericidal efficacy against S. aureus. Impressively, GHa4R presented antibacterial activity against methicillin-resistant S. aureus (MRSA). It was barely affected by temperature, pH, and storage period, showing high stability. Furthermore, it increased the permeability of the cell membrane and damaged the membrane integrity, leading to cell death. In addition, GHa4R did not induce antibiotic resistance in S. aureus in 30 days, but the MIC of vancomycin was doubled. It not only inhibited S. aureus biofilm formation but also eradicated 24 h-biofilms. CONCLUSION: The above-mentioned characteristics make GHa4R a promising candidate for the treatment of S. aureus infections.

Identification of RT-qPCR reference genes suitable for gene function studies in the pitaya canker disease pathogen Neoscytalidium dimidiatum.

Neoscytalidium dimidiatum is the main causal agent of pitaya canker. Most studies of virulence and pathogenicity genes have measured expression levels using real-time quantitative polymerase chain reaction (RT-qPCR). Suitable reference genes are essential for ensuring that estimates of gene expression levels by RT-qPCR are accurate. However, no reference genes can be robustly applied across all contexts and species. No studies to date have evaluated the most effective reference genes for normalizing gene expression levels estimated by RT-qPCR in N. dimidiatum. In this study, RT-qPCR data for individual candidate reference genes were analyzed using four different methods: the delta Ct method and the geNorm, NormFinder, and BestKeeper algorithms. We evaluated the utility of eight candidate reference genes (18S rRNA, Actin (1), Actin (2), Actin, GAPDH (1), GAPDH (2), UBQ, and Tubulin) for normalizing expression levels estimated by RT-qPCR in N. dimidiatum at different developmental stages, at different temperatures, and during interaction with pitaya. All candidate reference genes were suitable for gene expression analysis except for Actin (2). Tubulin and Actin (1) were the most stably expressed reference genes under different temperatures. Actin (1) and Actin were the most stably expressed reference genes in N. dimidiatum at different developmental stages. Tubulin and UBQ were the most stably expressed reference genes during interaction with pitaya. Actin and 18s rRNA were the most stably expressed across all experimental conditions. Subsequently, Tubulin and UBQ were further investigated in analyses of pectinase expression during the pitaya-N. dimidiatum interaction. Our results provide insights that will aid future RT-qPCR studies of gene expression in N. dimidiatum.

Arginine replacement of histidine on temporin-GHa enhances the antimicrobial and antibiofilm efficacy against Staphylococcus aureus.

Antimicrobial peptides (AMPs) show broad-spectrum microbicidal activity against bacteria, fungi, and viruses, and have been considered as one of the most promising candidates to overcome bacterial antimicrobial resistance. Structural modification of AMPs is an effective strategy to develop high-efficiency and low-toxicity antibacterial agents. A series of peptides GHaR6R, GHaR7R, GHaR8R, and GHaR9W with arginine replacement of histidine (His) derived from temporin-GHa of Hylarana guentheri were designed and synthesized. These derived peptides exhibit antibacterial activity against Staphylococcus aureus, and GHaR8R exerts bactericidal effect within 15 min at 4 × MIC (25 µm). The derived peptides caused rapid depolarization of bacteria, and the cell membrane damage was monitored using quartz crystal microbalance with dissipation assay, which suggests that they target cell membranes to exert antibacterial effects. The derived peptides can effectively eradicate mature biofilms of S. aureus. Taken together, the derived peptides are promising antibacterial agent candidates against S. aureus.

Studies on HBcAg-rBlo t 5-21 Fusion Protein Vaccine That Alleviates Blomia tropicalis Airway Inflammation.

Background: In tropical and subtropical areas, allergens from the dust mite species Blomia tropicalis are common causes of allergic rhinitis and asthma. Blomia tropicalis has two main allergens: Blo t 5 and Blo t 21. Aim: To generate a chimeric virus-like particle containing HBcAg, Blo t 5 and Blo t 21 that can treat allergies caused by Blomia tropicalis. Methods: To produce allergic asthma in mice, prokaryotic expression and purification of Blomia tropicalis allergens rBlo t 5, rBlo t 21, and recombinant fusion allergen rBlo t 5-21 were utilized in the study. We created a hepatitis B core antigen (HBcAg) and rBlo t 5-21 fusion prokaryotic expression plasmid. HBcAg-rBlo t 5-21 was purified after expression and tested by transmission electron microscopy (TEM). Furthermore, the protein HBcAg-rBlo t 5-21 was employed as a protein vaccination. Results: In allergy-induced mouse model experiments, the fusion allergen rBlo t 5-21 was more effective than the individual allergens rBlo t 5 and rBlo t 21 at inducing allergy. We found that vaccinating allergic mice with the recombinant fusion protein vaccine HBcAg-rBlo t 5-21 alleviated allergy symptoms elicited by the rBlo t 5-21 allergen. Vaccination with HBcAg-rBlo t 5-21 resulted in a decrease in total serum IgE levels, suppression of anaphylaxis, and reduction of inflammatory cell infiltration into lung tissue as compared to the PBS group. Conclusion: HBcAg-rBlo t 5-21, a protein vaccine containing both the hepatitis B core antigen and the Blomia tropicalis fusion allergen rBlo t 5-21, could be a suitable vaccination for preventing allergy disorders caused by Blomia tropicalis.

Tuning the Micro-coordination Environment of Al in Dealumination Y Zeolite to Enhance Electron Transfer at the Cu-Mn Oxides Interface for Highly Efficient Catalytic Ozonation of Toluene at Low Temperatures.

The development of stable, highly active, and inexpensive catalysts for the ozone catalytic oxidation of volatile organic compounds (VOCs) is challenging but of great significance. Herein, the micro-coordination environment of Al in commercial Y zeolite was regulated by a specific dealumination method and then the dealuminated Y zeolite was used as the support of Cu-Mn oxides. The optimized catalyst Cu-Mn/DY exhibited excellent performance with around 95% of toluene removal at 30 °C. Besides, the catalyst delivered satisfactory stability in both high-humidity conditions and long-term reactions, which is attributed to more active oxygen vacancies and acidic sites, especially the strong Lewis acid sites newly formed in the catalyst. The decrease in the electron cloud density around aluminum species enhanced electron transfer at the interface between Cu-Mn oxides. Moreover, extra-framework octahedrally coordinated Al in the support promoted the electronic metal-support interaction (EMSI). Compared with single Mn catalysts, the incorporation of the Cu component changed the degradation pathway of toluene. Benzoic acid, as the intermediate of toluene oxidation, can directly ring-open on Cu-doped catalysts rather than being further oxidized to other byproducts, which increased the rate of the catalytic reaction. This work provides a new insight and theoretical guidance into the rational design of efficient catalysts for the catalytic ozonation of VOCs.

Effects of a redox-active diketone on the photochemical transformation of roxarsone: Mechanisms and environmental implications.

Organoarsenical antibiotics pose a severe threat to the environment and human health. In aquatic environment, dissolved organic matter (DOM)-mediated photochemical transformation is one of the main processes in the fate of organoarsenics. Dicarbonyl is a typical redox-active moiety in DOM. However, the knowledge on the photoconversion of organoarsenics by DOM, especially the contributions of dicarbonyl moieties is still limited. Here, we systematically investigated the photochemical transformation of three organoarsenics with the simplest ß-diketone, acetylacetone (AcAc), as a model dicarbonyl moiety of DOM. The presence of AcAc significantly enhanced the photochemical conversion of roxarsone (ROX), whereas only minor effects were observed for 3-amino-4-hydroxyphenylarsonic acid (HAPA) and arsanilic acid (ASA), because the latter two (with an amino (-NH2) group) are more photoactive than ROX (with a nitro (-NO2) group). The results demonstrate that AcAc was a potent photo-activator and the reduction of -NO2 to -NH2 might be a rate-limiting step in the phototransformation of ROX. At a 1:1 M ratio of AcAc to ROX, the photochemical transformation rate of ROX was increased by 7 folds. In O2-rich environment, singlet oxygen, peroxide radicals, and ·OH were the main reactive species that led to the breakage of the C-As bond in ROX and the oxidation of the released arsono group to arsenate, whereas the triplet-excited state of AcAc (3AcAc*) and carbon-centered radicals from the photolysis of AcAc dominated in the reductive transformation of ROX. In anoxic environment, 3-amino-4-hydroxyphenylarsonic acid was one of the main reductive transformation intermediates of ROX, whose photolysis rate was about 35 times that of ROX. The knowledge obtained here is of great significance to better understand the fate of organoarsenics in natural environment.

Four temporin-derived peptides exhibit antimicrobial and antibiofilm activities against methicillin-resistant.

Temporin-GHa (GHa) was cloned from , showing a weak antimicrobial activity. In order to improve its bactericidal efficacy, GHaR6R, GHaR7R, GHaR8R and GHaR9W were designed and synthesized. Compared to the parent peptide, the GHa-derived peptides show potent antimicrobial activities against methicillin-resistant (MRSA), which is the main pathogen with high morbidity and mortality that causes various infections in humans. These peptides exert bactericidal actions on MRSA by permeabilizing the cytoplasmic membranes and damaging membrane integrity. All of the four peptides exhibit excellent stability under harsh conditions, including extreme temperature and salts. Furthermore, they inhibit the formation of biofilm and eradicate mature biofilm of MRSA. The GHa-derived peptides decrease bacterial surface hydrophobicity, autoaggregation and polysaccharide intercellular adhesion synthesis in concentration-dependent manner. Real-time quantitative reverse transcription PCR analysis revealed that the peptides downregulate the expression of adhesion genes involved in biofilm formation. Except for GHaR7R, the other three peptides have low hemolytic toxicity against human erythrocytes. In the presence of human erythrocytes, GHaR7R, GHaR8R and GHaR9W interact with MRSA preferentially. GHaR6R, GHaR8R and GHaR9W show less toxicity toward normal cells HL-7702 and hFOB1.19. These results suggest that the GHa-derived peptides may be promising antimicrobial candidates against MRSA infections.

Genetic characterization of nuclear export factor NXT1 and its paralog NXT2 in primates and murine rodents.

Translocation of RNA across the nuclear envelope relies on transport receptors. Receptor nuclear transport factor 2 (NTF2)-like export protein 1 (NXT1 [also called p15 or p15-1]) shuttles between the nucleus and cytoplasm of metazoan cells and contributes to the nuclear export of a diverse spectrum of RNAs. NXT2 (also called p15-2), a paralog of NXT1 in eutherians, also has implications for RNA nuclear export. A comprehensive description is currently lacking as to the genetic signature of these molecules. In this study, we analyzed genetic changes in the NXT1 and NXT2 genes in primates and murine rodents, including the commonly used model organisms Macaca spp., Mus musculus, and Rattus norvegicus. The results show that NXT1 has been subject to functional constraints in both phylogenetic lineages. Conversely, NXT2 exhibits discrepant patterns of genetic changes between these taxa. Murine NXT2 has evolved conservatively; by contrast, adaptive selection has frequently contributed to genetic changes in primate NXT2. The genetic discrepancy of the NXT2 orthologs leads to the suggestion that they had experienced quite different evolutionary fates potentially constituting different functional implementations in these taxa. These findings raise awareness of further study on different organisms to comprehensively understand their functional characteristics.

Molecular dynamic and pharmacological studies on protein-engineered hirudin variants of Hirudinaria manillensis and Hirudo medicinalis.

BACKGROUND AND PURPOSE: Hirudin variants are the most powerful thrombin inhibitors discovered to date, with a lower risk of bleeding than heparin. For anticoagulation, the C-termini of hirudin variants bind to the exocite I of thrombin. Anticoagulant effects of gene-recombinant hirudin are weaker than natural hirudin for the reason of lacking tyrosine O-sulfation at C-terminus. EXPERIMENTAL APPROACH: An integrative pharmacological study was carried out using molecular dynamic, molecular biological and in vivo and in vitro experiments to elucidate the anticoagulant effects of protein-engineered hirudins. KEY RESULTS: Molecular dynamic analysis showed that modifications of the C-termini of hirudin variant 1 of Hirudo medicinalis (HV1) and hirudin variant 2 of Hirudinaria manillensis (HM2) changed the binding energy of the C-termini to human thrombin. The study indicated that Asp61 of HM2 that corresponds to sulfated Tyr63 of HV1 is critical for inhibiting thrombin activities. Further, the anticoagulant effects of HV1 and HM2 were improved when the amino acid residues adjacent to Asp61 were mutated to Asp. These improvements were prolongation of the activated partial thromboplastin time, prothrombin time and thrombin time of human blood, and decreased Ki and IC50 values. In the in vivo experiments, mutations at C-termini of HV1 and HM2 significantly changed partial thromboplastin time, prothrombin and thrombin time CONCLUSION AND IMPLICATIONS: The study indicated that the anticoagulant effects of gene-engineered HM2 are stronger than gene-engineered HV1 and HM2-E60D-I62D has the strongest effects and could be an antithrombotic with better therapeutic effects.

Predicting signaling pathways regulating demyelination in a rat model of lithium-pilocarpine-induced acute epilepsy: A proteomics study.

Demyelination is observed in animal models of intractable epilepsy (IE). Epileptogenesis damages the myelin sheath and dysregulates oligodendrocyte precursor cell (OPC) development. However, the molecular pathways regulating demyelination in epilepsy are unclear. Here, we predicted the molecular mechanisms regulating demyelination in a rat model of lithium-pilocarpine hydrochloride-induced epilepsy. We identified DGKA/Mboat2/Inpp5j and NOS/Keratin 28 as the main target molecules that regulate demyelination via glycerolipid and glycerophospholipid metabolism, phosphatidylinositol signaling, and estrogen signaling in demyelinated forebrain slice cultures (FSCs). In seizure-like FCSs, the actin cytoskeleton was regulated by Cnp and MBP via Pak4/Tmsb4x (also known as Tß4) and Kif5c/Kntc1. Tß4 possibly prevented OPC differentiation and maturation and inhibited MBP phosphorylation via the p38MAPK/ERK1/JNK1 pathway. The MAPK signaling pathway was more likely activated in seizure-like FCSs than in demyelinated FCSs. pMBP expression was decreased in the hippocampus of lithium-pilocarpine hydrochloride-induced acute epilepsy rats. The expression of remyelination-related factors was suppressed in the hippocampus and corpus callosum in lithium-pilocarpine hydrochloride-induced epilepsy rats. These findings suggest that the actin cytoskeleton, Tß4, and MAPK signaling pathways regulate the decrease in pMBP in the hippocampus in a rat model of epilepsy. Our results indicate that regulating the actin cytoskeleton, Tß4, and MAPK signaling pathways may facilitate the prevention of demyelination in IE.

An all-in-one approach for synthesis and functionalization of nano colloidal gold with acetylacetone.

Controllable synthesis, proper dispersion, and feasible functionalization are crucial requirements for the application of nanomaterials in many scenarios. Here, we report an all-in-one approach for the synthesis and functionalization of gold nanoparticles (AuNPs) with the simplestß-diketone, acetylacetone (AcAc). With this approach, the particle size of the resultant AuNPs was tunable by simply adjusting the light intensity or AcAc dosage. Moreover, owing to the capping role of AcAc, the resultant AuNPs could be stably dispersed in water for a year without obvious change in morphology and photochemical property. Formation of ligand to metal charge transfer complexes was found to play an important role in the redox conversion of Au with AcAc. Meanwhile, the moderate complexation ability enables the surface AcAc on the AuNPs to undergo ligand exchange reactions (LER). With the aid of Ag+, the AuNPs underwent LER with glutathione and exhibited enhanced photoluminescence (PL) with a maximum of 22-fold increase in PL intensity. The PL response was linear to the concentration of glutathione in the range of 0-500µM. Such a LER makes the obtained AuNPs being good imaging probes. To the best of our knowledge, this is the first work on illustrating the roles of AcAc as a multifunctional ligand in fabrication of NPs, which sheds new light on the surface modulation in synthesis of nanomaterials.