Search

The study explores the osteogenic differentiation mechanism and immune response of biodegradable calcium phosphate/calcium sulfate cements reinforced with cellulose.

Japanese encephalitis virus (JEV), an important neurotropic pathogen, belongs to the genus Flavivirus of the family Flaviviridae and has caused huge threat to public health. It is still obscure regarding the functions of stem-loop (SL) and dumbbell (DB) domains of JEV 3��� UTR in viral replication and virulence. In the current study, using the infectious clone of JEV SA14 strain as a backbone, we constructed a series of deletion mutants of 3��� UTR to investigate their effects on virus replication. The results showed that partial deletions within SL or DB domain had no apparent effects on virus replication in both mammalian (BHK-21) and mosquito (C6/36) cells, suggesting that they were not involved in viral host-specific replication. However, the entire SL domain deletion (��VR) significantly reduced virus replication in both cell lines, indicating the important role of the complete SL domain in virus replication. The revertant of ��VR mutant virus was obtained by serial passage in BHK-21 cells that acquired a duplication of DB domain (DB-dup) in the 3��� UTR, which greatly restored virus replication as well as the capability to produce the subgenomic flavivirus RNAs (sfRNAs). Interestingly, the DB-dup mutant virus was highly attenuated in C57BL/6 mice despite replicating similar to WT JEV. These findings demonstrate the significant roles of the duplicated structures in 3��� UTR in JEV replication and provide a novel strategy for the design of live-attenuated vaccines.

The extremely high transmission rate of SARS-CoV-2 and severe cases of COVID-19 pose the two critical challenges in the battle against COVID-19. Increasing evidence has shown that the viral spike (S) protein-driven syncytia may be responsible for these two events. Intensive attention has thus been devoted to seeking S-guided syncytium inhibitors. However, the current screening campaigns mainly rely on either live virus-based or plasmid-based method, which are always greatly limited by the shortage of high-level biosafety BSL-3 facilities or too much labour-intensive work. Here, we constructed a new hybrid VEEV-SARS-CoV-2-S-eGFP reporter vector through replacement of the structural genes of Venezuelan equine encephalitis virus (VEEV) with the S protein of SARS-CoV-2 as the single structural protein. VEEV-SARS-CoV-2-S-eGFP can propagate steadily through cell-to-cell transmission pathway in S- and ACE2-dependent manner, forming GFP positive syncytia. In addition, a significant dose-dependent decay in GFP signals was observed in VEEV-SARS-CoV-2-S-eGFP replicating cells upon treatment with SARS-CoV-2 antiserum or entry inhibitors, providing further evidence that VEEV-SARS-CoV-2-S-eGFP system is highly sensitive to characterize the anti-syncytium-formation activity of antiviral agents. More importantly, the assay is able to be performed in a BSL-2 laboratory without manipulation of live SARS-CoV-2. Taken together, our work establishes a more convenient and efficient VEEV-SARS-CoV-2-S-eGFP replicating cells-based method for rapid screening of inhibitors blocking syncytium formation.

A high-efficiency regeneration and genetic transformation system is indispensable for generating desirable traits in important trees such as Eucalyptus. However, lower regeneration efficiency is common for most varieties because of the recalcitrance of this genus. Here, a stable and highly efficient in vitro organogenesis protocol and Agrobacterium-mediated genetic transformation system of Eucalyptus were developed, and transgenic plants were obtained. In this protocol, the preferred explants were the top and middle stem internodes from in vitro micro-shoots of the E. urophylla × E. tereticornis hybrid. Modified Woody Plant Medium (mWPM) containing 0.025 mg·L-1 thidiazuron (TDZ) and 0.10 mg·L-1 indole-3-butyric acid (IBA) was used to induce multiple adventitious buds that allowed 85.6% shoot formation. The binary vector pBI121 carrying the neomycin phosphotransferase II (nptII) and β-glucuronidase (uidA) genes was applied for transformation. The preferred internodes were precultured for 0 to 3 d and infected with A. tumefaciens strain GV3101 grown to a bacterial density of 0.5 (OD600). Then, they were transferred to a co-culture medium supplemented with 50 μM acetosyringone (AS) and co-cultured for 2 d in the dark. The transgenic adventitious buds formed in regeneration medium, which was replaced by the same medium with a 2-wk subculture interval through kanamycin selection. Using the aforementioned method, transgenic plantlets can be obtained within 3 mo with a transformation frequency of 3.8%, which was verified by polymerase chain reaction amplification (PCR) and histochemical analysis of GUS activity. The constructed genetic transformation system will lay a foundation for mining gene functions and further molecular breeding of Eucalyptus.

Osteoporosis is a growing public health concern worldwide. To avoid extra surgeries, developing biodegradable bone cement is critical for the treatment of osteoporosis. Herein, we designed calcium phosphate/calcium sulfate cement reinforced with sodium carboxymethyl cellulose (CMC/OPC). It presents an appropriate physicochemical performance for clinical handling. Meanwhile, CMC/OPC bone cement promotes osteogenic differentiation

The Omicron variant is sweeping the world, which displays striking immune escape potential through mutations at key antigenic sites on the spike protein, making broad-spectrum SARS-CoV-2 prevention or therapeutical strategies urgently needed. Previously, we have reported a hACE2-targeting neutralizing antibody 3E8, which could efficiently block both prototype SARS-CoV-2 and Delta variant infections in prophylactic mouse models, having the potential of broad-spectrum to prevent SARS-CoV-2. However, preparation of monoclonal neutralizing antibodies is severely limited by the time-consuming process and the relative high cost. Here, we utilized a modified VEEV replicon with two subgenomic (sg) promoters engineered to express the light and heavy chains of the 3E8 mAb. The feasibility and protective efficacy of replicating mRNA encoding 3E8 against Omicron infection in the hamster were demonstrated through the lung targeting delivery with the help of VEEV-VRP. Overall, we developed a safe and cost-effective platform of broad-spectrum to prevent SARS-CoV-2 infection.

Carboxymethyl konjac glucomannan (CMKGM) is an anionic derivative of konjac glucomannan (KGM). Its coacervation with ovalbumin (OVA) was investigated through turbidity and coacervate yield measurem...

Sustained expression of B-cell receptor (BCR) critically contributes to the development of diffuse large B-cell lymphoma (DLBCL). However, little is known on the mechanism regulating BCR expression. In the present study, we explored the biological significance of functional intergenic repeating RNA element (FIRRE) in DLBCL and its regulation on BCR. Functional impacts of FIRRE on cell viability, transformation, and apoptosis were examined by MTT, colony formation, and flow cytometry, respectively. The interaction between FIRRE and polypyrimidine tract binding protein 1 (PTBP1) was identified by RNA pull-down and verified using RNA immunoprecipitation (RIP) assays. The effects of FIRRE and PTBP1 on Smurf2 mRNA were examined by RIP, RNA pull-down, and mRNA stability assays. Smurf2-mediated BCR ubiquitination was investigated using co-immunoprecipitation, ubiquitination, and protein stability assays. In vivo, xenograft models were used to assess the impacts of targeting FIRRE on DLBCL growth. FIRRE was specifically up-regulated in and essentially maintained multiple malignant behaviors of BCR-dependent DLBCL cells. Through the interaction with PTBP1, FIRRE promoted the mRNA decay of Smurf2, a ubiquitin ligase for the degradation BCR protein. Targeting FIRRE was sufficient to regulat Smurf2 and BCR expressions and inhibit DLBCL malignancy both in vivo and in vitro. FIRRE-PTBP1 interaction, by simulating Smurf2 mRNA decay and stabilizing BCR, promotes the development of DLBCL. Consequently, targeting this signaling mechanism may provide therapeutic benefits for DLBCL.

A dual-receptor interaction with a polysialoganglioside and synaptic vesicle glycoprotein 2 (SV2) is required for botulinum neurotoxin A (BoNT) toxicity. Here, we review what is currently known about the BoNT/A-SV2 interaction based on structural studies. Currently, five crystal structures of the receptor-binding domain (Hc) of BoNT subtypes A1 and A2 complexed to the large luminal domain (LD4) of SV2C have been determined. On the basis of the available structures, we will discuss the importance of protein-protein and protein-carbohydrate interactions for BoNT/A toxicity as well as the high plasticity of BoNT/A for receptor recognition by tolerating a variety of side-chain interactions at the interface. A plausible explanation how receptor-binding specificity of BoNT/A may be achieved without an extensive and conserved side chain-side chain interaction network will be provided.

AIM:To observe the changes of retinal and choroid tissue structure in SD rats exposed to blue light from 455nm-470nm array, and to analyze the relationship between irradiation time and tissue structure changes. METHODS: Totally 24 healthy SD male rats of 6wk were selected and randomly divided into normal control group(n=6)and experimental group(n=18). The normal control group was fed for 6wk without any intervention. The experimental group was divided into three groups, which were exposed to the array blue light emitting apparatus(455nm-470nm, 391Lx)for 3, 6 and 12h each day for 6wk.RESULTS: The fundus tissue structure was intact and the cell morphology was normal in the control group. With the extension of blue light irradiation time, the choroid fiber connective tissue of rats in all experimental groups presented hyaline changes, local loose edema, proliferation of small blood vessels, thinning of pigment layer, thinning of cells, gradual reduction of the number of visual cells, and local disappearance. At 3h, the nucleus staining of the experimental group was clear, and no definite changes were observed in the bipolar cell layer and ganglion cell layer. In the 6h and 12h groups, nucleus pyknosis was observed, bipolar cell layer was mildly proliferated, and local cytoplasm was formed in the ganglion cell layer.CONCLUSION: The photoreceptor cells of retina become thinner, atrophy and disappear with the extension of blue light irradiation time. There was no significant relationship between the injury of pigment epithelial cells and the prolonged exposure time of blue light.

In our previous study, we found that a new type of Chikungunya virus particle with a complete capsid deletion (ΔC-CHIKV) is still infectious in BHK-21 cells and demonstrated its potential as a live attenuated vaccine candidate. However, the low yield as well as the disability to propagate in vaccine production cell line Vero of ΔC-CHIKV are not practical for commercial vaccine development. In this study, we not only achieved the successful propagation of the viral particle in Vero cells, but significantly improved its yield through construction of a chimeric VEEV-ΔC-CHIKV and extensive passage in Vero cells. Mechanistically, high production of VEEV-ΔC-CHIKV is due to the improvement of viral RNA packaging efficiency conferred by adaptive mutations, especially those in envelope proteins. Similar to ΔC-CHIKV, the passaged VEEV-ΔC-CHIKV is safe, immunogenic, and efficacious, which protects mice from CHIKV challenge after only one shot of immunization. Our study demonstrates that the utilization of infectious capsidless viral particle of CHIKV as a vaccine candidate is a practical strategy for the development of alphavirus vaccine. IMPORTANCE Chikungunya virus (CHIKV) is one of important emerging alphaviruses. Currently, there are no licensed vaccines against CHIKV infection. We have previously found a new type of Chikungunya virus particle with a complete capsid deletion (ΔC-CHIKV) as a live attenuated vaccine candidate that is not suitable for commercial vaccine development with the low viral titer production. In this study, we significantly improved its production through construction of a chimeric VEEV-ΔC-CHIKV. Our results proved the utilization of infectious capsidless viral particle of CHIKV as a safe and practical vaccine candidate.

Coacervation of the lipase from Aspergillus oryzae (AOL) with chitosan was a feasible way to fabricate lipase-loaded particles and the optimum conditions were phase separation pH 5.5, chitosan to AOL mass ratio 1:5, and temperature 25 °C in the absence of NaCl, which conferred an AOL loading efficiency of up to 95.48% and activity recovery of 69.60%. The AOL-chitosan coacervates were highly porous and more susceptible to weight loss upon heating. Coacervation with chitosan increased the activity of AOL and shifted its optimum pH from 7.0 to 6.0, but exerted no effect on its optimum temperature (45 °C). Thermal deactivation kinetics analysis revealed that the coacervated AOL was more thermal stable, while the Michaelis-Menten kinetics analysis indicated that coacervation with chitosan increased the V

The lung is the prophylaxis target against SARS-CoV-2 infection, and neutralizing antibodies are a leading class of biological products against various infectious viral pathogen. In this study, we develop a safe and cost-effective platform to express neutralizing antibody in the lung with replicating mRNA basing on alphavirus replicon particle (VRP) delivery system, to prevent SARS-CoV-2 infections. First, a modified VEEV replicon with two subgenomic (sg) promoters was engineered to translate the light and heavy chains of antibody simultaneously, for expression and assembly of neutralizing anti-SARS-CoV-2 antibody CB6. Second, the feasibility and protective efficacy of replicating mRNA against SARS-CoV-2 infection were demonstrated through both in vitro and in vivo assays. The lung target delivery with the help of VRP system resulted in efficiently block SARS-CoV-2 infection with reducing viral titer and less tissue damage in the lung of mice. Overall, our data suggests that expressing neutralizing antibodies in the lungs with the help of self-replicating mRNA could potentially be a promising prophylaxis approach against SARS-CoV-2 infection.

Introduction Pain management modalities after proximal femoral fracture are variable and have been studied extensively. Regional anesthesia, specifically femoral nerve (FNB) and fascia iliaca compartment blocks (FICB), can be used to provide analgesia preoperatively. Methods Systematic searches of all related literature were conducted in the Medline, Embase, and Cochrane Central Register of Controlled Trials databases. Randomized controlled trials (RCTs) of proximal femoral fractures were included. The pain scores at different time points, opioid requirement in 24 h, mean arterial pressure, time for spinal anesthesia, patient satisfaction, and incidence of side effects between the 2 groups were extracted throughout the study. Results Fifteen RCTs including 1240 patients met the inclusion criteria. The present meta-analysis indicated that compared with FNB, FICB could decrease the visual analog scale (VAS) scores at 4 h after surgery (P < .05). The incidence of side effects (nausea, vomiting, and sedation) was lower in the FNB group (P < .05). Compared to the FICB, no significant difference was found at any other observed time point. Additionally, no difference was found in opioid requirement at 24 h, mean arterial pressure, time for spinal anesthesia, or patient satisfaction (P > .05). Conclusions FICB demonstrates a reduction in VAS score at 4 while FNB decreases the risk of several adverse events. More high-quality RCTs are necessary for proper comparison of the efficacy and safety of FNB and FICB.

The suitability of the perilla seed oil Pickering emulsion stabilized by the ovalbumin (OVA) - gum Arabic (GA) polyelectrolyte complex for spray drying was investigated and the resultant powder was characterized. The OVA - GA complex conferred enhanced stability to the emulsion than OVA, GA, and their mixture. The viscosity of the Pickering emulsion was highly sensitive to stabilizer concentration and that fabricated by 2% OVA - GA complex showed acceptable viscosity and powder yield. The Pickering emulsion was more effective in preventing oil leakage during spray drying than the OVA-stabilized emulsion and the resultant powder possessed an oil content of up to 77.7%. Besides, the spray-dried Pickering emulsion powder showed greater rehydration and better flowability than that of the OVA-stabilized emulsion powder. Hence, the Pickering emulsion stabilized by the OVA - GA polyelectrolyte complex is promising as a novel feed for the production of oil powders by spray drying.

The genus Flavivirus comprises numerous emerging and re‐emerging arboviruses causing human illness. Vaccines are the best approach to prevent flavivirus diseases. But pathogen diversities are always one of the major hindrances for timely development of new vaccines when confronting unpredicted flavivirus outbreaks. We used West Nile virus (WNV) as a model to develop a new live‐attenuated vaccine (LAV), WNV‐poly(A), by replacing 5ʹ portion (corresponding to SL and DB domains in WNV) of 3ʹ‐UTR with internal poly(A) tract. WNV‐poly(A) not only propagated efficiently in Vero cells, but also was highly attenuated in mouse model. A single‐dose vaccination elicited robust and long‐lasting immune responses, conferring full protection against WNV challenge. Such “poly(A)” vaccine strategy may be promising for wide application in the development of flavivirus LAVs because of its general target regions in flaviviruses., West Nile virus (WNV) is one of the many members of the genus Flavivirus known to cause human diseases. Here we present a novel live attenuated WNV vaccine, WNV‐poly(A), that protects against WNV infections in a mouse model.

Background. Femoral nerve block (FNB) and fascia iliac compartment block (FICB) are alternative methods of pain relief during hip surgery. Nevertheless, the effectiveness and safety of FNB compared with FICB are yet to be fully determined. Methods. Electronic databases were systematically searched. Only randomized controlled trials (RCTs) on hip surgery were included. Postoperatively, the pain scores at different time points, narcotic requirements in 24 h, mean arterial pressure, spinal anesthesia (SA) time, patient satisfaction, and adverse effect rates between the two groups were extracted throughout the study. Results. Fourteen RCTs including 1179 patients were included. Compared to the FICB, FNB decreased the VAS scores postoperatively at 24 h at rest ( P < 0.05 ) and the incidence rate of some side effects (nausea, vomiting, and sedation) ( P < 0.05 ). However, compared to the FICB, no significant difference was found in the FNB regarding the VAS scores postoperatively at any of the other time points (2 min, 20 min, 2 h, 24 h at movement, 48 h at rest, and 48 h at movement). Patients in both groups had similar narcotic needs after 24 h, mean arterial pressure, SA time, and patient satisfaction ( P > 0.05 ). Conclusions. FNB has more advantages in reducing VAS scores postoperatively at 24 h at rest and the odds of some adverse effects. A better quality RCT is needed to properly compare FNB with FICB.

The evolutionary conserved YidC is a unique dual-function protein that adopts insertase and chaperone conformations. The TM1 helix of Escherichia coli YidC mediates the interaction between the YidC chaperone and the Sec translocon. Here, we report the first crystal structure of Thermotoga maritima YidC (TmYidC) including the TM1 helix (PDB ID: 6Y86). The TM1 helix lies on the periplasmic side of the bilayer forming an angle of about 15 degrees with the membrane surface. Our functional studies suggest a role of TM1 for the species-specific interaction with the Sec translocon. The reconstitution data and the superimposition of TmYidC with known YidC structures suggest an active insertase conformation for YidC. Molecular dynamics (MD) simulations of TmYidC provide evidence that the TM1 helix acts as a membrane anchor for the YidC insertase and highlight the flexibility of the C1 region underlining its ability to switch between insertase and chaperone conformations. A structure-based model is proposed to rationalize how YidC performs the insertase and chaperone functions by re-positioning of the TM1 helix and the other structural elements.

Mayaro virus (MAYV) is a neglected mosquito-borne alphavirus that causes illness similar to Chikungunya (CHIKV), Dengue (DENV) and Zika virus (ZIKV). Currently, there is no specific treatment or vaccine against MAYV infection. To develop an efficient antiviral screening assay for MAYV, we constructed the infectious clones of MAYV strain BeAr 20290 and its eGFP reporter virus. The reporter virus exhibited high replication capacity indistinguishable with the wild type MAYV, and was genetically stable within at least five rounds of passages in BHK-21 cell. The expression of eGFP correlated well with the viral replication. Using the known inhibitor ribavirin, we confirmed that the MAYV-eGFP reporter virus could be used for antiviral screening to identify the specific inhibitors against MAYV. Using the MAYV-eGFP based antiviral assay, we found that the compound 6-Azauridine which had antiviral activity against CHIKV and SFV, showed a significant inhibitory effect on MAYV replication.