The efficacy and safety of perioperative glucocorticoid for total knee arthroplasty: a systematic review and meta-analysis.

BACKGROUND: An increasing number of individuals undergo total knee arthroplasty (TKA), which can result in pain, limited motor function and adverse complications such as infection, nausea and vomiting. Glucocorticoids have been shown anti-inflammatory and antiemetic effects, but can also elevate blood glucose levels and increase the risk of wound infection. Thus, it is essential to investigate the efficacy and safety of glucocorticoid usage in TKA. METHOD: A comprehensive systematic search of PubMed, Medline, EMBASE, Cochrane databases, to identify relevant randomized controlled trials (RCTs) of glucocorticoid application in TKA. The primary outcomes assessed were the postoperative pain assessment. Secondary outcomes included the range of motion in knee joint, levels of inflammatory cytokines, adverse complications, and the length of hospital stay. RESULTS: Thirty-six randomized controlled trials were included in the final analysis. The glucocorticoid group exhibited significant reduction in the resting VAS scores on postoperative days 1, 2 (POD1, 2)and postoperative 3 months (POM3), as well as decreased morphine consumption on POD1 and increased range of motion (ROM) in knee joint on POD1, 3. Additionally, the glucocorticoid group exhibited decreased levels of postoperative inflammatory cytokines and the incidence of PONV along with a shorter length of hospital stay. The blood glucose concentration was significantly increased in the glucocorticoid group on POD1 compared with the control group. While the blood glucose on POD2 and occurrence of postoperative adverse complications were similar between two groups including wound infection and venous thrombosis. The periarticular injection analgesia (PIA) group demonstrated lower VAS scores on POD2 comparing to the systemic administration (SA) group according to two studies. However, there was no significant difference of the resting VAS on POD1 and POD2 between PIA and SA group across all studies. CONCLUSION: Perioperative glucocorticoids treatment in TKA significantly reduced short-term pain score and opioid-use which was probably not patient relevant. The application of glucocorticoids in TKA implied a beneficial trend in analgesic, anti-inflammatory, and antiemetic effects, as well as improved range of motion and shortened hospital stay. While it will not increase the risk of continued high glucose, postoperative wound infection and venous thrombosis.

Solid-waste-recycled CuO/C3N4 S-scheme heterojunctions for efficient photocatalytic antibiotic degradation.

With the increasing severity of antibiotic pollution, the development of effective green photocatalysts for the degradation of organic pollutants in water has attracted extensive attention. Herein, we have prepared CuO/C3N4 S-scheme heterogeneous photocatalysts via recycling Cu resources from Cu-containing electroplating sludges. By mediating the acid leaching process, copper in electroplating sludges was dissolved selectively, while other metal species were retained in the residues. The CuO/C3N4 S-scheme heterojunction not only effectively suppressed the recombination of photogenerated charge carriers of C3N4, but also preserved the strong reducing electrons of C3N4 and the strong oxidizing holes of CuO, retaining the outstanding redox ability of CuO/C3N4. Therefore, CuO/C3N4 photocatalysts exhibited good catalytic performance in the degradation of tetracycline (over 95% in 2 h). In addition, CuO/C3N4 S-scheme heterojunctions achieved a high mineralization rate (45% in 2 hours), thus reducing secondary pollution during the degradation. This work provides a reliable direction for designing novel S-scheme heterojunction photocatalytic materials by using metal sources in solid waste.

Aspergillus fumigatus escape mechanisms from its harsh survival environments.

Aspergillus fumigatus is a ubiquitous pathogenic mold and causes several diseases, including mycotoxicosis, allergic reactions, and systemic diseases (invasive aspergillosis), with high mortality rates. In its ecological niche, the fungus has evolved and mastered many reply strategies to resist and survive against negative threats, including harsh environmental stress and deficiency of essential nutrients from natural environments, immunity responses and drug treatments in host, and competition from symbiotic microorganisms. Hence, treating A. fumigatus infection is a growing challenge. In this review, we summarized A. fumigatus reply strategies and escape mechanisms and clarified the main competitive or symbiotic relationships between A. fumigatus, viruses, bacteria, or fungi in host microecology. Additionally, we discussed the contemporary drug repertoire used to treat A. fumigatus and the latest evidence of potential resistance mechanisms. This review provides valuable knowledge which will stimulate further investigations and clinical applications for treating and preventing A. fumigatus infections. KEY POINTS: • Harsh living environment was a great challenge for A. fumigatus survival. • A. fumigatus has evolved multiple strategies to escape host immune responses. • A. fumigatus withstands antifungal drugs via intrinsic escape mechanisms.

Comparative analysis of the biological characteristics and mechanisms of azole resistance of clinical Aspergillus fumigatus strains.

Aspergillus fumigatus is a common causative pathogen of aspergillosis. At present, triazole resistance of A. fumigatus poses an important challenge to human health globally. In this study, the biological characteristics and mechanisms of azole resistance of five A. fumigatus strains (AF1, AF2, AF4, AF5, and AF8) were explored. There were notable differences in the sporulation and biofilm formation abilities of the five test strains as compared to the standard strain AF293. The ability of strain AF1 to avoid phagocytosis by MH-S cells was significantly decreased as compared to strain AF293, while that of strains AF2, AF4, and AF5 were significantly increased. Fungal burden analysis with Galleria mellonella larvae revealed differences in pathogenicity among the five strains. Moreover, the broth microdilution and E-test assays confirmed that strains AF1 and AF2 were resistant to itraconazole and isaconazole, while strains AF4, AF5, and AF8 were resistant to voriconazole and isaconazole. Strains AF1 and AF2 carried the cyp51A mutations TR34/L98H/V242I/S297T/F495I combined with the hmg1 mutation S541G, whereas strains AF4 and AF8 carried the cyp51A mutation TR46/Y121F/V242I/T289A, while strain AF5 had no cyp51A mutation. Real-time quantitative polymerase chain reaction (RT-qPCR) analysis revealed differences in the expression levels of genes associated with ergosterol synthesis and efflux pumps among the five strains. In addition, transcriptomics, RT-qPCR, and the NAD+/NADH ratio demonstrated that the mechanism of voriconazole resistance of strain AF5 was related to overexpression of genes associated with energy production and efflux pumps. These findings will help to further elucidate the triazole resistance mechanism in A. fumigatus.

Effects of geo-climate factors on phenotypic variation in cone and seed traits of Pinus yunnanensis.

Evaluating variations in reproductive traits and the response of the variations to geo-climate conditions are essential for understanding the persistence, evolution, and range dynamics of plant populations. However, there are insufficient studies to attempt to analyze the importance of geo-climate factors in explaining within- or among-population variation in reproductive traits. We examined 14 traits for 2671 cones of Pinus yunnanensis collected from nine populations in the mountains of Southwest China to characterize the patterns of phenotypic variation of traits and estimate environmental effects on these trait performances and trait variation. We found the contribution of intrapopulation variation to the overall variation was greater than the interpopulation variation and the larger coefficients of variation for the populations lying at the edge of northern and southern regions. Climatic variables are more important than geographical and tree size variables in their relationships to cone and seed traits. Populations in more humid and warmer climate expressed greater cone and seed weight and seed number but lower seed abortion rate, while the larger coefficients of variation in seed weight and number were detected in northern and southern marginal regions with drier or colder climate. Our study illustrates that intraspecific trait variation should be considered when examining plant species response to changing climate and suggests that the high variability rather than high quality of seed traits in the marginal regions with drier or colder climate might foster plant-population persistence in stressful conditions.

Responses of plant carbon and nitrogen assimilations to nitrogen addition in a subtropical forest: Canopy addition vs. understory addition.

The global atmospheric nitrogen (N) deposition has intensified in recent years, resulting in a complex impact on forest ecosystems. This study investigated the effects of canopy (CAN) and understory additions of N (UAN) on leaf carbon (C) and N assimilations, as well as growth parameters of representative woody plant species in an evergreen broad-leaved forest, i.e. Castanea henryi, Schefflera heptaphylla, Blastus cochinchinensis, and Lasianthus chinensis. The results showed that leaf N assimilation key enzyme nitrate reductase (NR) activities of B. cochinchinensis and S. heptaphylla were significantly decreased by UAN, and were significantly decreased by CAN for C. henryi. CAN significantly decreased the nitrite reductase activity of C. henryi, while significantly increased that of L. chinensis. However, the Amax values of each woody species were not significantly different among control (CK), CAN, and UAN. Community surveys demonstrated that CAN and UAN inhibited the growth (diameter at breast height, height, or crown width) of the representative large tree, C. henryi, while promoting the growths of understory woody species (B. cochinchinensis and L. chinensis). Overall, N addition was found to change the physiological processes of N and C metabolisms of the dominant woody species in an evergreen broad-leaved forest. The community of subtropical evergreen broad-leaved forests may further decline and its C fixation capacity may be detrimentally changed under N deposition in the future.

A multi-level analysis on the causes of train-pedestrian collisions in Southwest China 2011-2020.

Collisions between trains and pedestrians are the primary cause of railway casualties. However, there remains a lack of comprehensive understanding regarding the underlying causes of this phenomenon. This study employs a multi-level approach to investigate the factors associated with the occurrence and severity of train-pedestrian collisions. The investigation is based on 2160 independent cases that occurred in southwest China from 2011 to 2020. Multiple contributing factors related to the victim, train, track, and socio-economic status of the surrounding district were examined, utilizing information from various sources. At the county level, several risk factors were identified in predicting the occurrence rate. These factors include higher population density and a greater number of normal-speed stations. However, the presence of high-speed train stations did not exhibit any significant impact. Additionally, the study found that regulations pertaining to protective fences were highly effective in reducing the occurrence rate. Regarding the prediction of collision severity, certain factors were found to increase the death rate. These factors include young men as victims, engaging in lying down or crossing behaviors, higher train speeds, gentle downhill slopes, lower education levels, and a higher proportion of the labor force. These findings emphasize the necessity of adopting a comprehensive perspective when examining the causes of train-pedestrian collisions. Furthermore, it underscores the significance of considering the notable differences between rapidly developing countries such as China and developed countries. Based on our findings, we also provide corresponding policy suggestions.

Nitrogen addition changes the canopy biological characteristics of dominant tree species in an evergreen broad-leaved forest.

Many studies have focused on the impact of nitrogen deposition on plants, but due to technical limitations, research on the responses of forest canopy to manipulated nitrogen deposition is relatively scarce. Based on a canopy nitrogen addition (CN) platform, this study used laboratory analysis and unmanned aerial vehicle (UAV) observations to assess the impact of CN on the canopy traits of dominant tree species (Engelhardia roxburghiana, Schima superba, and Castanea henryi) in an evergreen broad-leaved forest in China. The results showed that nitrogen application at 25 kg N ha-1 y-1 (CN25) and 50 kg N ha-1 y-1 (CN50) significantly increased the actual net photosynthetic rate (An) of all the three tree species. CN25 significantly increased superoxide dismutase (SOD), catalase (CAT), and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activities in C. henryi. CN50 significantly increased the leaf area of all the three tree species and significantly reduced the leaf thickness of C. henryi, and significantly increased the POD and Rubisco activities in S. superba and C. henryi. CN significantly changed the number of forest gaps, but did not significantly change the area of forest gaps within the sample plots. CN25 significantly decreased the vertical projection area but increased the canopy flowering coverage of S. superba in dominant directions. CN25 and CN50 significantly increased the flowering coverage of C. henryi in favorable directions. It is found that under long-term (10-year) nitrogen addition, the balance between carbon fixation and antioxidant defense functions of E. roxburghiana may be broken down, but the carbon assimilation, antioxidant capacity and reproduction potential of S. superba and C. henryi may be well coordinated, which will have a potential impact on the species composition and ecological functions of the evergreen broad-leaved forest. This study may also provide scientific basis for forest management in the context of enhanced atmospheric nitrogen deposition.

The potential role of plant secondary metabolites on antifungal and immunomodulatory effect.

With the widespread use of antibiotic drugs worldwide and the global increase in the number of immunodeficient patients, fungal infections have become a serious threat to global public health security. Moreover, the evolution of fungal resistance to existing antifungal drugs is on the rise. To address these issues, the development of new antifungal drugs or fungal inhibitors needs to be targeted urgently. Plant secondary metabolites are characterized by a wide variety of chemical structures, low price, high availability, high antimicrobial activity, and few side effects. Therefore, plant secondary metabolites may be important resources for the identification and development of novel antifungal drugs. However, there are few studies to summarize those contents. In this review, the antifungal modes of action of plant secondary metabolites toward different types of fungi and fungal infections are covered, as well as highlighting immunomodulatory effects on the human body. This review of the literature should lay the foundation for research into new antifungal drugs and the discovery of new targets. KEY POINTS: • Immunocompromised patients who are infected the drug-resistant fungi are increasing. • Plant secondary metabolites toward various fungal targets are covered. • Plant secondary metabolites with immunomodulatory effect are verified in vivo.

Preparation and Properties of Natural Polysaccharide-Based Drug Delivery Nanoparticles.

In recent years, natural polysaccharides have been widely used in the preparation of drug delivery systems. In this paper, novel polysaccharide-based nanoparticles were prepared by layer-by-layer assembly technology using silica as a template. The layers of nanoparticles were constructed based on the electrostatic interaction between a new pectin named NPGP and chitosan (CS). The targeting ability of nanoparticles was formed by grafting the RGD peptide, a tri-peptide motif containing arginine, glycine, and aspartic acid with high affinity to integrin receptors. The layer-by-layer assembly nanoparticles (RGD-(NPGP/CS)3NPGP) exhibited a high encapsulation efficiency (83.23 ± 6.12%), loading capacity (76.51 ± 1.24%), and pH-sensitive release property for doxorubicin. The RGD-(NPGP/CS)3NPGP nanoparticles showed better targeting to HCT-116 cells, the integrin αvß3 high expression human colonic epithelial tumor cell line with higher uptake efficiency than MCF7 cells, the human breast carcinoma cell line with normal integrin expression. In vitro antitumor activity tests showed that the doxorubicin-loaded nanoparticles could effectively inhibit the proliferation of the HCT-116 cells. In conclusion, RGD-(NPGP/CS)3NPGP nanoparticles have potential as novel anticancer drug carriers because of their good targeting and drug-carrying activity.

In Situ Polymerized Flame Retardant Gel Electrolyte for High-Performance and Safety-Enhanced Lithium Metal Batteries.

A flame retardant gel electrolyte (FRGE) is deemed as one of the most promising electrolytes to relieve the problems of safety hazards and interfacial incompatibility of Li metal batteries. Herein, a novel solvent triethyl 2-fluoro-2-phosphonoacetate (TFPA) with outstanding flame retardancy is introduced in the polymer skeleton synthesized by in situ polymerization of the monomer polyethylene glycol dimethacrylate (PEGDMA) and the cross-linker pentaerythritol tetraacrylate (PETEA). The FRGE exhibits superb interfacial compatibility with Li metal anodes and inhibits uncontrolled Li dendrite growth. This can be ascribed to the restriction of free phosphate molecules by the polymer skeleton, thus realizing a stable cycling performance over 500 h at 1 mA cm-2 and 1 mAh cm-2 in the Li||Li symmetric cell. In addition, the high ionic conductivity (3.15 mS cm-1) and Li+ transference number (0.47) of the FRGE further enhance the electrochemical performance of the correspondent battery. As a result, the LiFePO4|FRGE|Li cell exhibits excellent long-term cycling life with a capacity retention of 94.6% after 700 cycles. This work points to a new pathway for the practical development of high-safety and high-energy-density Li metal-based batteries.

Construction and Performance Evaluation of Nicandra physalodes (Linn.) Gaertn. Polysaccharide-Based Nanogel.

The nanogels made from these polysaccharides and their derivatives are often used to construct drug delivery systems owing to their biocompatible, biodegradable, non-toxic, water-soluble, and bioactive characteristics. In this work, a novel pectin with unique gelling properties was extracted from the seed of Nicandra physalodes (NPGP). The structural research indicated that NPGP was a low methoxyl pectin with a high content of galacturonic acid. NPGP-based nanogels (NGs) were accomplished employing the water in oil (W/O) nano-emulsion method. The cysteamine containing reduction-responsive bond and integrin-targeting RGD peptide were also grafted onto NPGP. The anti-tumor drug doxorubicin hydrochloride (DOX) was loaded during the formation of NGs, and the performance of DOX delivery was studied. The NGs were characterized by UV-vis, DLS, TEM, FT-IR, and XPS. The results showed that the prepared NGs were nanosized (167.6 ± 53.86 nm), had excellent encapsulation efficiency (91.61 ± 0.85%), and possessed a fine drug loading capacity (8.40 ± 0.16%). The drug release experiment showed that DOX@NPGP-SS-RGD had good redox-responsive performance. Furthermore, the results of cell experiments revealed good biocompatibility of prepared NGs, along with selective absorption by HCT-116 cells through integrin receptor-mediated endocytosis to play an anti-tumor effect. These studies indicated the potential application of NPGP-based NGs as targeted drug delivery systems.

Integrating surface structure via triphenyl phosphate treatment to stabilize Li-rich Mn-based cathode materials.

Li-rich Mn-based layered oxides (LLOs) have emerged as one of the most promising cathode materials for the next-generation lithium-ion batteries (LIBs) because of their high energy density, high specific capacity, and environmental friendliness. These materials, however, have drawbacks such as capacity degradation, low initial coulombic efficiency (ICE), voltage decay, and poor rate performance due to irreversible oxygen release and structural deterioration during cycling. Herein, we present a facile method of triphenyl phosphate (TPP) surface treatment to create an integrated surface structure on LLOs that includes oxygen vacancies, Li3PO4, and carbon. When used for LIBs, the treated LLOs show an increased initial coulombic efficiency (ICE) of 83.6% and capacity retention of 84.2% at 1C after 200 cycles. It is suggested that the enhanced performance of the treated LLOs can be attributed to the synergetic functions of each component in the integrated surface, such as the oxygen vacancy and Li3PO4 being able to inhibit the evolution of oxygen and accelerate the transport of lithium ions, while the carbon layer can restrain undesirable interfacial side reactions and reduce the dissolution of transition metals. Furthermore, electrochemical impedance spectroscopy (EIS) and galvanostatic intermittent titration technique (GITT) prove an enhanced kinetic property of the treated LLOs cathode, and ex-situ X-ray diffractometer shows a suppressed structural transformation of TPP-treated LLOs during the battery reaction. This study provides an effective strategy for constructing an integrated surface structure on LLOs to achieve high-energy cathode materials in LIBs.

Secretions from Serratia marcescens Inhibit the Growth and Biofilm Formation of Candida spp. and Cryptococcus neoformans.

Candida spp. and Cryptococcus are conditional pathogenic fungi that commonly infect immunocompromised patients. Over the past few decades, the increase in antifungal resistance has prompted the development of new antifungal agents. In this study, we explored the potential antifungal effects of secretions from Serratia marcescens on Candida spp. and Cryptococcus neoformans. We confirmed that the supernatant of S. marcescens inhibited fungal growth, suppressed hyphal and biofilm formation, and downregulated the expression of hyphae-specific genes and virulence-related genes in Candida spp. and C. neoformans. Furthermore, the S. marcescens supernatant retained biological stability after heat, pH, and protease K treatment. The chemical profile of the S. marcescens supernatant was characterized by ultra-high-performance liquid chromatography-linear ion trap/orbitrap high resolution mass spectrometry analysis and a total of 61 compounds with an mzCloud best match of greater than 70 were identified. In vivo, treatment with the S. marcescens supernatant reduced the mortality of fungi-infected Galleria mellonella. Taken together, our results revealed that the stable antifungal substances in the supernatant of S. marcescens have promising potential applications in the development of new antifungal agents.

Riboflavin Targets the Cellular Metabolic and Ribosomal Pathways of Candida albicans In Vitro and Exhibits Efficacy against Oropharyngeal Candidiasis.

Oropharyngeal candidiasis (OPC), which has a high incidence in immunocompromised and denture stomatitis patients, is commonly caused by Candida albicans infection and in some cases develops into disseminated candidiasis throughout the throat and esophagus, resulting in high mortality. New drugs are needed to combat OPC because of the limited treatment options currently available and increasing resistance to existing drugs. Here, we confirmed that riboflavin (RF), a cofactor of flavin adenine mononucleotide and flavin adenine dinucleotide, has broad-spectrum anti-Candida activity. The formation of C. albicans hyphae and biofilm was inhibited by RF. Mechanistically, RF disrupted membrane and cell wall integrity, as well as promoting reactive oxygen species and pyruvate accumulation. Furthermore, RF targeted multiple essential pathways via functional disruption of thiamine and RF metabolic pathways, central carbon metabolism, and ribosome metabolism. Similar to the results in vitro, the inhibitory effect of RF on C. albicans hyphae was confirmed in a mouse model of OPC. Moreover, after 5 consecutive days of intraperitoneal injection, RF exhibited therapeutic efficacy, as demonstrated by phenotype investigation, the fungal burden, and histopathological analysis. These findings revealed that RF exerts a multifaceted anti-Candida effect and has potential benefits in the treatment of OPC. IMPORTANCE Candida species are common pathogens in fungal infections, causing mucosal infection and invasive infection in immunodeficient patients. Given the limited classes of drugs and resistance to these drugs, new antifungal agents need to be developed. Drug repurposing is a potential method for antifungal drug development. This study demonstrated that riboflavin (RF) exhibited broad-spectrum anti-Candida activity. RF affected multiple targets involving the membrane and cell wall integrity, the accumulation of reactive oxygen species and pyruvate, and the altered metabolic pathways in C. albicans. Moreover, RF exhibited efficacy in the treatment of C. albicans in an oropharyngeal candidiasis mouse model. Taken together, the antifungal activity and the promising clinical application of RF were highlighted.

Simulated nitrogen deposition promotes the carbon assimilation of shrubs rather than tree species in an evergreen broad-leaved forest.

Although understory addition of nitrogen (UAN) is commonly used to simulate nitrogen deposition in field studies in forest ecosystems, it ignores the effects of atmospheric nitrogen deposition on the canopy. We studied the effects of nitrogen deposition simulated by UAN and by canopy addition of nitrogen (CAN) on leaf structure, chemical properties, Calvin cycle, and photosynthate distribution strategy of representative woody plant species in a subtropical evergreen broadleaved forest in South China. The results showed that maximum photosynthetic rate (Amax) of shrub species Blastus cochinchinensis and Ardisia quinquegona under CAN treatments was significantly higher than that of UAN treatments at the same N addition concentration. The concentrations of intermediates (PGK, DPGA and G3P) in Calvin cycle of B. cochinchinensis and A. quinquegona, and Castanea henryi were significantly increased with CAN treatments, but the opposite was true with UAN treatments. CAN25 significantly increased starch concentrations of shrub species Lasianthus chinensis and B. cochinchinensis, and significantly decreased sucrose concentrations of shrub species A. quinquegona and tree species C. henryi. Correlation analyses showed that nitrogen application amount under different modes helped explain the changes in Amax and Calvin cycle intermediates. In summary, nitrogen deposition may promote the Amax and Calvin cycle of shrub species, and the adaptability of shrub species to nitrogen deposition is higher than that of tree species, which may help to explain the degradation of subtropical evergreen broad-leaved forest.

Antifungal activity of vitamin D3 against Candida albicans in vitro and in vivo.

The incidence of intra-abdominal candidiasis (IAC), characterized by high morbidity and mortality, has become a serious concern. The limitations of current antifungal drugs on the market underscores the importance of the development of novel antifungal agents. In the present study, the antifungal activity of vitamin D3 (VD3) against various Candida species was investigated. In vitro, the broth microdilution method and solid plate assay confirmed that VD3 inhibited the growth of Candida spp. in a broad-spectrum, dose-dependent manner. VD3 also had a significant antifungal effect on the initiation, development, and maturation phases of biofilm formation in Candida albicans. The mechanism of VD3 action was explored by transcriptomics and reverse transcription quantitative PCR (RT-qPCR) analysis, and showed that VD3 affects ribosome biogenesis, coenzyme metabolism, and carbon metabolism. These results suggested that VD3 may have multitarget effects against C. albicans. In the murine IAC model, VD3 reduced the fungal burden in the liver, kidneys, and small intestine. Further histopathological analysis and quantification of plasma cytokine levels confirmed that VD3 treatment significantly decreased the infiltration of inflammatory cells and the levels of plasma interferon (IFN)-γ and tumor necrosis factor (TNF)-α. Taken together, these findings suggest a new antifungal mechanism for VD3 and indicate that VD3 could be an effective therapeutic agent for use in IAC treatment.

Maturation of subtilisin-like protease NbSLP1 from microsporidia Nosema bombycis.

Microsporidia are obligate intracellular parasites and possess a unique way of invading hosts, namely germination. Microsporidia are able to infect almost all animal cells by germination. During the process, the polar tube extrudes from the spores within, thus injecting infectious sporoplasm into the host cells. Previous studies indicated that subtilisin-like protease 1 (NbSLP1) of microsporidia Nosema bombycis were located at the polar cap of germinated spores where the polar tube extrusion. We hypothesized that NbSLP1 is an essential player in the germination process. Normally, SLP need to be activated by autoproteolysis under conditions. In this study, we found that the signal peptide of NbSLP1 affected the activation of protease, two self-cleavage sites were involved in NbSLP1 maturation between Ala104Asp105 and Ala124Asp125 respectively. Mutants at catalytic triad of NbSLP1 confirmed the decreasing of autoproteolysis. This study demonstrates that intramolecular proteolysis is required for NbSLP1 maturation. The protease undergoes a series of sequential N-terminal cleavage events to generate the mature enzyme. Like other subtilisin-like enzymes, catalytic triad of NbSLP1 are significant for the self-activation of NbSLP1. In conclusion, clarifying the maturation of NbSLP1 will be valuable for understanding the polar tube ejection mechanism of germination.

Robust route to H2O2 and H2 via intermediate water splitting enabled by capitalizing on minimum vanadium-doped piezocatalysts.

H2O2 is an environmentally friendly chemical for a wide range of water treatments. The industrial production of H2O2 is an anthraquinone oxidation process, which, however, consumes extensive energy and produces pollution. Here we report a green and sustainable piezocatalytic intermediate water splitting process to simultaneously obtain H2O2 and H2 using single crystal vanadium (V)-doped NaNbO3 (V-NaNbO3) nanocubes as catalysts. The introduction of V improves the specific surface area and active sites of NaNbO3. Notably, V-NaNbO3 piezocatalysts of 10 mg exhibit 3.1-fold higher piezocatalytic efficiency than the same catalysts of 50 mg, as more piezocatalysts lead to higher probability of aggregation. The aggregation causes reducing active sites and decreased built-in electric field due to the neutralization between different nano-catalysts. Remarkably, piezocatalytic H2O2 and H2 production rates of V-NaNbO3 (10 mol%) nanocubes (102.6 and 346.2 µmol·g-1·h-1, respectively) are increased by 2.2 and 4.6 times compared to the as-prepared pristine NaNbO3 counterparts, respectively. This improved catalytic efficiency is attributed to the promoted piezo-response and more active sites of NaNbO3 catalysts after V doping, as uncovered by piezo-response force microscopy (PFM) and density functional theory (DFT) simulation. More importantly, our DFT results illustrate that inducing V could reduce the dynamic barrier of water dissociation over NaNbO3, thus enhancing the yield of H2O2 and H2. This facile yet robust piezocatalytic route using minimal amounts of catalysts to obtain H2O2 and H2 may stand out as a promising candidate for environmental applications and water splitting. Electronic Supplementary Material: Supplementary material (typical Raman spectra of NaNbO3 and V-NaNbO3 with various doping concentrations (Fig. S1). XPS spectra of Na 1s (Fig. S2). PL spectra of solution obtained from the piezocatalytic system using NaNbO3 and V-NaNbO3 (10 mol%) as the catalysts after 1 h (Fig. S3). The length of NaNbO3 and V-NaNbO3 nanocubes calculated from XRD data of their (101) planes (Table S1)) is available in the online version of this article at 10.1007/s12274-022-4506-0.