The evolution and diurnal expression patterns of photosynthetic pathway genes of the invasive alien weed,Mikania micrantha

Mikania micrantha is a fast-growing global invasive weed species that causes severe damage to natural ecosystems and very large economic losses of forest and crop production.It has advantages in photosynthesis,including a similar net photosynthetic rate as C4 plants and a higher carbon fixation capacity.We used a combination of genomics and transcriptomics approaches to study the evolutionary mechanisms and circadian expression patterns of M.micrantha.In M.micrantha,16 positive selection genes focused on photoreaction and utilization of photoassimilates.In different tissues,98.1%of the genes associated with photoresponse had high expression in stems,and more than half of the genes of the C4 cycle had higher expression in stems than in leaves.In stomatal opening and closing,2 genes of carbonic anhydrase(CAs)had higher expression at 18:00 than at 8:00,and the slow anion channel 1(SLAC1)and high-leaf-temperature 1 kinase(HT1)genes were expressed at low levels at 18:00.In addition,genes associated with photosynthesis had higher expression levels at 7:00 and 17:00.We hypothesized that M.micrantha may undergo photosynthesis in the stem and flower organs and that some stomata of the leaves were opening at night by CO_(2)signals.In addition,its evolution may attenuate photoinhibition at high light intensities,and enhance more efficient of photosynthesis during low light intensity.And the tissue-specific photosynthetic types and different diurnal pattern of photosynthetic-related genes may contribute to its rapid colonization of new habitats of M.micrantha.

Cu/碳纳米纤维负载脂肪酸定形相变材料的制备与性能

结合静电纺丝、物理吸附、预氧化炭化和原位还原的技术与原理,制备了3种不同铜纳米粒子含量的Cu/碳纳米纤维膜(Cu/CNFs1~3),从此作为定形相变材料(FSPCM)的支撑基体;根据最低共熔点理论和Schrader方程计算出月桂酸-肉豆蔻酸-硬脂酸(LA-MA-SA)三元脂肪酸的质量比例,用作制备FSPCM的相变物质。通过物理吸附法制备了Cu/CNFs负载LA-MA-SA的FSPCM1~3。探讨了不同铜纳米粒子含量的CNFs对FSPCM形貌与导热性能的影响。结果表明,FSPCM1~3的熔融时间分别缩短了23.0%、51.8%和38.2%,结晶时间分别缩短了47.8%、64.0%和62.6%。制备的FSPCM1~3的熔融相变温度和熔融热焓在32~36℃和88~122 kJ/kg之间,结晶相变温度和结晶热焓分别在24~26℃和89~120.9 kJ/kg之间。

Enhanced Potassium‑Ion Storage of the 3D Carbon Superstructure by Manipulating the Nitrogen‑Doped Species and Morphology

Potassium-ion batteries(PIBs)are attractive for gridscale energy storage due to the abundant potassium resource and high energy density.The key to achieving high-performance and large-scale energy storage technology lies in seeking eco-efficient synthetic processes to the design of suitable anode materials.Herein,a spherical sponge-like carbon superstructure(NCS)assembled by 2D nanosheets is rationally and efficiently designed for K+storage.The optimized NCS electrode exhibits an outstanding rate capability,high reversible specific capacity(250 mAh g^(−1) at 200 mA g^(−1) after 300 cycles),and promising cycling performance(205 mAh g^(−1) at 1000 mA g^(−1) after 2000 cycles).The superior performance can be attributed to the unique robust spherical structure and 3D electrical transfer network together with nitrogen-rich nanosheets.Moreover,the regulation of the nitrogen doping types and morphology of NCS-5 is also discussed in detail based on the experiments results and density functional theory calculations.This strategy for manipulating the structure and properties of 3D materials is expected to meet the grand challenges for advanced carbon materials as high-performance PIB anodes in practical applications.

Genetic variants in TP53 and MDM2 associated with male infertility in Chinese population

The TP53, a transcriptional regulator and tumor suppressor, is functionally important in spermatogenesis. MDM2 is a key regulator of the p53 pathway and modulates p53 activity. Both proteins have been functionally linked to germ cell apoptosis, which may affect human infertility, but very little is known on how common polymorphisms in these genes may influence germ cell apoptosis and the risk of male infertility. Thus, this study was designed to test whether three previously described polymorphisms 72Arg〉Pro （rs1042522） and the Ex2＋ 19C〉T （rs2287498） in TP53, and the 5＇ untranslated region （5＇ UTR） 309T〉G （rs937283） in MDM2, are associated with idiopathic male infertility in a Chinese population. The three polymorphisms were genotyped using OpenArray assay in a hospital-based case-control study, including 580 infertile patients and 580 fertile controls. Our analyses revealed that TP53 Ex2-1-19C〉T and MDM2 309T〉G polymorphisms are associated with male infertility. Furthermore, we detected a nearly statistically significant additive interaction between TP53 rs2287498 and MDM2 rs937283 for the development of male infertility （Pinteraction--O-055）- In summary, this study found preliminary evidence, demonstrating that genetic variants in genes of the TP53 pathway are risk factors for male infertility.

On quantitative structure-activity relationships between hydrazine derivatives and β irradiation

In this study, solutions of hydrazine and its derivatives were irradiated using a pulsed electron beam to determine the half-reaction time of radiolysis. 3 D structures of the hydrazine derivatives were optimized, and their energies were calculated using density functional theory with the B3 LYP method and 6-311 +(3 d, 3 p) basis set.For the first time, the 3 D quantitative structure-activity relationship(QSAR) equation describing the relationship between the hydrazine derivative structures and rate of radiolysis has been established using SPSS software.Pearson correlation analysis revealed a close correlation between the total energies of the molecules and half-reaction times. In the QSAR equation, Y =-7583.464 +54.687 X_1+94333.586 X_2,Y,X_1,and X_2 are the half-reaction time, total energy of the molecule, and orbital transition energy, respectively. The significance levels of the regression coefficients were 0.006 and 0.031, i.e., both less than 0.05. Thus, this model fully explains the relationship between hydrazine derivatives and β radiolysis stability.The results show that the total energy of the molecule and orbital transition energy are the main factors that influence the β radiolysis stability of these hydrazine derivatives.

Chordoma of petrosal mastoid region:A case report

BACKGROUND Chordoma is a rare low-grade malignant tumor originating from embryonic notochordal tissue mainly occurring in the axial bone,mostly in the sphenooccipital junction and sacrococcyx,which accounts for approximately 1%of all malignant bone tumors and 0.1%–0.2%of intracranial tumors.Chordoma in the petrous mastoid region is rare.CASE SUMMARY We describe a 36-year-old male patient with chordoma in the left petrous mastoid region.The main clinical manifestations were pain and discomfort,which lasted for 2 years.Magnetic resonance imaging showed a lobulated mass in the left petrous mastoid with an unclear boundary and obvious enhancement.The tumor was completely removed after surgical treatment,and a histological examination confirmed that the tumor was a chordoma.During 5 years of follow-up,no clinical or radiological evidence of recurrence or metastasis was found.CONCLUSION Chordoma in the petrosal mastoid region is rare but should be included in differential diagnosis of petrosal mastoid tumors.

Efficacy and safety of oral Chinese herbal medicine combined with nucleoside antiviral drugs against recurrent genital herpes:a systematic review and meta-analysis

Background:To compare the efficacy and safety of Chinese herbal medicine combined with nucleoside antiviral drugs and nucleoside antiviral drugs alone in treating recurrent genital herpes.Methods:PubMed,Embase,Web of Science,Cochrane Library,Chinese Biomedical Literature Database,China National Knowledge Internet,VIP Database,and Wanfang Data were searched from inception to April 2021.Randomized controlled trials on the efficacy and safety of oral Chinese herbal medicine combined with nucleoside antiviral drugs for recurrent genital herpes were collected.All included trials were independently assessed by two reviewers with the Cochrane risk-of-bias tool,and a meta-analysis was conducted using Review Manager 5.4.Results:Compared with the use of nucleoside antiviral drugs alone,combination therapy with oral Chinese herbal medicine plus nucleoside antiviral drugs effectively reduced the herpes recurrence rate after the end of treatment(3 months:P=0.0002;6 months:P<0.00001;1 year:P<0.00001)and the number of recurrences each year(P<0.00001),improved the recurrent Genital Herpes Quality of Life Questionnaire score(P<0.00001),and regulated the levels of interferon-γ,interleukin-2,tumor necrosis factor-α,and T lymphocyte subsets in the peripheral blood,and the difference was statistically significant.Different subgroups reported mixed results with respect to the efficacy in the short term.The incidence of adverse reactions and the time of symptom disappearance between the two groups were not significantly different.Conclusion:Chinese herbal medicine combined with nucleoside antiviral drugs can effectively reduce the recurrence rate of recurrent genital herpes,improve the patient’s quality of life and enhance the body’s immunity.Considering the possible risk of publication bias,more high-quality randomized controlled trials are still needed to verify the conclusions of this article.

An Analysis of the Condensation Temperature of Elements of Extrasolar Planetary Systems

Using high signal-to-noise ratio spectra of extrasolar planet-hosting stars, we obtained the atmospheric parameters, accurate metallicities and the differential abundance for 15 elements （C, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn, Ni and Ba）. In a search for possible signatures of metal-rich material accreting onto the parent stars, we found that, for a given element, there is no significant trend of increasing [X/H] with increasing condensation temperature To. In our sample of planet-harboring stars, the volatile and refractory elements behave similarly, and we can not confirm if there exists any significant dependence on the condensation temperature Tc.

Construction of electron rich Fe active sites by FeCu alloy anchoring on carbon nitride for photocatalytic nitrogen reduction

Given the clean and inexhaustible solar energy from solar light,photocatalytic ammonia synthesis is extremely appealing.However,high electron-hole recombination rates and insufficient active sites severely limited N2 photoreaction reduction.Herein,we designed and fabricated FeCu alloy nanoparticles anchored on carbon nitride nanosheets with excellent photocatalyt ic ammonia synthesis performance.As a coupler between Fe and carbon nitride,Cu promotes the separation of photogenerated charge carriers in carbon nitride under solar light irradiation,and renters the semiconductor a forceful electron donor for the Fe active sites.The accumulated electrons at Fe sites furtherly facilitated the adsorption and activation of the molecular nitrogen.Besides,the uniform dispersed FeCu alloy nanoparticles were on carbon nitride nanosheets enhanced the stability of photocataly tic nitrogen reduction reaction,making the artificial photocataly tic ammonia synthesis more sustainable for application.This work highlights that a direct electron transfer channel can be used to regulate the photochemical nitrogen fixation network.

Unsupervised social network embedding via adaptive specific mappings

In this paper,we address the problem of unsuperised social network embedding,which aims to embed network nodes,including node attributes,into a latent low dimensional space.In recent methods,the fusion mechanism of node attributes and network structure has been proposed for the problem and achieved impressive prediction performance.However,the non-linear property of node attributes and network structure is not efficiently fused in existing methods,which is potentially helpful in learning a better network embedding.To this end,in this paper,we propose a novel model called ASM(Adaptive Specific Mapping)based on encoder-decoder framework.In encoder,we use the kernel mapping to capture the non-linear property of both node attributes and network structure.In particular,we adopt two feature mapping functions,namely an untrainable function for node attributes and a trainable function for network structure.By the mapping functions,we obtain the low dimensional feature vectors for node attributes and network structure,respectively.Then,we design an attention layer to combine the learning of both feature vectors and adaptively learn the node embedding.In encoder,we adopt the component of reconstruction for the training process of learning node attributes and network structure.We conducted a set of experiments on seven real-world social network datasets.The experimental results verify the effectiveness and efficiency of our method in comparison with state-of-the-art baselines.

The crucial roles of m^(6)A RNA modifications in cutaneous cancers:Implications in pathogenesis,metastasis,drug resistance,and targeted therapies

N6-methyladenosine(m^(6)A)is the most abundant internal modification on RNA.It is a dynamical and reversible process,which is regulated by m^(6)A methyltransferase and m^(6)A demethylase.The m^(6)A modified RNA can be specifically recognized by the m^(6)A reader,leading to RNA splicing,maturation,degradation or translation.The abnormality of m^(6)A RNA modification is closely related to a variety of biological processes,especially the occurrence and development of tumors.Recent studies have shown that m^(6)A RNA modification is involved in the pathogenesis of skin cancers.However,the precise molecular mechanisms of m^(6)A-mediated cutaneous tumorigenesis have not been fully elucidated.Therefore,this review will summarize the biological characteristics of m^(6)A modification,its regulatory role and mechanism in skin cancers,and the recent research progress of m^(6)A-related molecular drugs,aiming to provide new ideas for clinical diagnosis and targeted therapy of cutaneous cancers.

The role of tumor size,ultrasonographic findings,and serum tumor markers in predicting the likelihood of malignant testicular histology

The clin ical predictive factors for maligna nt testicular histology remain unclear because of the low prevale nee.Therefore,the aim of this study was to investigate predictors of malignant histology for testicular masses and decide more testis-sparing surgeries before surgery.This retrospective study enrolled 325 consecutive testicular mass patients who underwent radical orchiectomy(310/325)or testicular preserving surgery(15/325)from January 2001 to June 2016.The clinicopathological factors,including tumor diameter,cryptorchidism history,ultraso und fin dings,serum alpha-fetoprotein,and human chorio nic gonadotropin(HCG)levels,were collected retrospectively for statistical an alysis.A predictive no mogram was also gen erated to evaluate the qua ntitative probability.Among all patients,247(76.0%)were diagnosed with a malignant testicular tumor and 78(24.0%)with benign histology.Larger tumor diameter(percm increased,hazard ratio[HR]=1.284,P=0.036),lower ultrasound echo(HR=3.191,P=0.001),higher ultrasound blood flow(HR=3.320,P<0.001),and abnormal blood HCG(HR=10.550,P<0.001)were significant predictive factors for malignant disease in all testicular mass patients?The nomogram generated was well calibrated for all predicti ons of malig nant probability,and the accuracy of the model no mogram measured by HarrelTs C statistic(C-in dex)was 0.92.According to our data,the proportion of patients who underwent radical orchiectomy for benign tumors(24.0%)was much larger tha n gen erally believed(10.0%).Our results in dicated that the diameter,ultras onic echo,ultras onic blood flow,and serum HCG levels could predict the malignancy in testicular mass patients.

1-Pbps orbital angular momentum fibre-optic transmission

Space-division multiplexing(SDM),as a main candidate for future ultra-high capacity fibre-optic communications,needs to address limitations to its scalability imposed by computation-intensive multi-input multi-output(MIMO)digital signal processing(DSP)required to eliminate the crosstalk caused by optical coupling between multiplexed spatial channels.By exploiting the unique propagation characteristics of orbital angular momentum(OAM)modes in ring core fibres(RCFs),a system that combines SDM and C+L band dense wavelength-division multiplexing(DWDM)in a 34 km 7-core RCF is demonstrated to transport a total of 24960 channels with a raw(net)capacity of 1.223(1.02)Peta-bit s−1(Pbps)and a spectral efficiency of 156.8(130.7)bit s−1 Hz−1.Remarkably for such a high channel count,the system only uses fixed-size 4×4 MIMO DSP modules with no more than 25 time-domain taps.Such ultra-low MIMO complexity is enabled by the simultaneous weak coupling among fibre cores and amongst non-degenerate OAM mode groups within each core that have a fixed number of 4 modes.These results take the capacity of OAM-based fibre-optic communications links over the 1 Pbps milestone for the first time.They also simultaneously represent the lowest MIMO complexity and the 2nd smallest fibre cladding diameter amongst reported few-mode multicore-fibre(FM-MCF)SDM systems of>1 Pbps capacity.We believe these results represent a major step forward in SDM transmission,as they manifest the significant potentials for further up-scaling the capacity per optical fibre whilst keeping MIMO processing to an ultra-low complexity level and in a modularly expandable fashion.

Effective electrocatalytic hydrodechlorination of 2,4,6-trichlorophenol by a novel Pd/MnO_(2)/Ni foam cathode

Pd modified electrodes possess problems such as easy agglomeration and low electrolytic ability,and the use of manganese dioxide(MnO_(2)) to facilitate Pd reduction of organic pollutants is just started.However,there is still a limited understanding of how to match the Pd load and MnO_(2) to realize optimal dechlorination efficiency at minimum cost.Here,a Pd/MnO_(2)/Ni foam cathode was successfully fabricated and applied for the efficient electrochemical dechlorination of 2,4,6-trichlorophenol(2,4,6-TCP).The optimal electrocatalytic hydrodechlorination(ECH)performance with 2,4,6-TCP dechlorination efficiency(92.58%in 180 min)was obtained when the concentration of PdCl_(2) precipitation was 1 mmol/L,the deposition time of MnO_(2) was 300 s and cathode potential was-0.8 V.Performance influenced by the exogenous factors(e.g.,initial pH and coexisted ions)were further investigated.It was found that the neutral pH was the most favorable for ECH and a reduction in dechlorination efficiency(6%~47.6%)was observed in presence of 5 mmol/L of NO_(2)^(-),NO_(3)^(-),S^(2-)or SO_(3)^(2-).Cyclic voltammetry(CV)and quenching experiments verified the existence of three hydrogen species on Pd surface,including adsorbed atomic hydrogen(H^(*)_(ads)),absorbed atomic hydrogen(H^(*)_(abs)),and molecular hydrogen(H_(2)).And the introduction of MnO_(2)promoted the generation of atomic H^(*).Only adsorbed atomic hydrogen(H^(*)_(ads)) was confirmed that it truly facilitated the ECH process.Besides H^(*)_(ads) induced reduction,the direct reduction by cathode electrons also participated in the 2,4,6-TCP dechlorination process.Pd/MnO_(2)/Ni foam cathode shows excellent dechlorination performance,fine stability and recyclable potential,which provides strategies for the effective degradation of persistent halogenated organic pollutants in groundwater.

Reprogramming of ovarian granulosa cells by YAP1 leads to development of high-grade cancer with mesenchymal lineage and serous features

Understanding the cell-of-origin of ovarian high grade serous cancer(HGSC)is the prerequisite for efficient prevention and early diagnosis of this most lethal gynecological cancer.Recently,a mesenchymal type of ovarian HGSC with the poorest prognosis among ovarian cancers was identified by both TCGA and AOCS studies.The cell-of-origin of this subtype of ovarian cancer is unknown.While pursuing studies to understand the role of the Hippo pathway in ovarian granulosa cell physiology and pathology,we unexpectedly found that the Yes-associated protein 1(YAP1),the major effector of the Hippo signaling pathway,induced dedifferentiation and reprogramming of the ovarian granulosa cells,a unique type of ovarian follicular cells with mesenchymal lineage and high plasticity,leading to the development of high grade ovarian cancer with serous features.Our research results unveil a potential cell-of-origin for a subtype of HGSC with mesenchymal features.

Ordered mesoporous carbon as an efficient heterogeneous catalyst to activate peroxydisulfate for degradation of sulfadiazine

Catalytic potential of carbon nanomaterials in peroxydisulfate(PDS)advanced oxidation systems for degradation of antibiotics remains poorly understood.This study revealed ordered mesoporous carbon(type CMK)acted as a superior catalyst for heterogeneous degradation of sulfadiazine(SDZ)in PDS sys-tem,with a first-order reaction kinetic constant(k)and total organic carbon(TOC)mineralization efficiency of 0.06 min^(–1) and 59.67%±3.4%within 60min,respectively.CMK catalyzed PDS system exhibited high degradation efficiencies of five other sulfonamides and three other types of antibiotics,verifying the broad-degradation capacity of antibiotics.Under neutral pH conditions,the optimal catalytic parameters were an initial SDZ concentration of 44.0mg/L,CMK dosage of 0.07g/L,and PDS dosage of 5.44mmol/L,respectively.X-ray photoelectron spectroscopy and Raman spectrum analysis confirmed that the defect structure at edge of CMK and oxygen-containing functional groups on surface of CMK were major active sites,contributing to the high catalytic activity.Free radical quenching analysis revealed that both SO_(4)•−and•OH were generated and participated in catalytic reaction.In addition,direct electron transfer by CMK to activate PDS also occurred,further promoting catalytic performance.Configuration of SDZ molecule was optimized using density functional theory,and the possible reaction sites in SDZ molecule were calculated using Fukui function.Combining ultra-high-performance liquid chromatography(UPLC)–mass spectrometry(MS)/MS analysis,three potential degradation pathways were proposed,including the direct removal of SO_(2)molecules,the 14S-17N fracture,and the 19C-20N and 19C-27N cleavage of the SDZ molecule.The study demonstrated that ordered mesoporous carbon could work as a feasible catalytic material for PDS advanced oxidation during removal of antibiotics from wastewater.

Perturbation of clopyralid on bio-denitrification and nitrite accumulation:Long-term performance and biological mechanism

The contaminant of herbicide clopyralid(3,6-dichloro-2-pyridine-carboxylic acid,CLP)poses a potential threat to the ecological system.However,there is a general lack of research devoted to the perturbation of CLP to the bio-denitrification process,and its biological response mechanism remains unclear.Herein,long-term exposure to CLP was systematically investigated to explore its influences on denitrification performance and dynamic microbial responses.Results showed that low-concentration of CLP(<15 mg/L)caused severe nitrite accumulation initially,while higher concentrations(35e60 mg/L)of CLP had no further effect after long-term acclimation.The mechanistic study demonstrated that CLP reduced nitrite reductase(NIR)activity and inhibited metabolic activity(carbon metabolism and nitrogen metabolism)by causing oxidative stress and membrane damage,resulting in nitrite accumulation.However,after more than 80 days of acclimation,almost no nitrite accumulation was found at 60 mg/L CLP.It was proposed that the secretion of extracellular polymeric substances(EPS)increased from 75.03 mg/g VSS at 15 mg/L CLP to 109.97 mg/g VSS at 60 mg/L CLP,which strengthened the protection of microbial cells and improved NIR activity and metabolic activities.Additionally,the biodiversity and richness of the microbial community experienced a U-shaped process.The relative abundance of denitrification-and carbon metabolism-associated microorganisms decreased initially and then recovered with the enrichment of microorganisms related to the secretion of EPS and N-acyl-homoserine lactones(AHLs).These microorganisms protected microbe from toxic substances and regulated their interactions among interand intra-species.This study revealed the biological response mechanism of denitrification after successive exposure to CLP and provided proper guidance for analyzing and treating herbicide-containing wastewater.

Investigation of colloidal biogenic sulfur flocculation:Optimization using response surface analysis

The colloidal properties of biogenic elemental sulfur（S^0）cause solid–liquid separation problems,such as poor settling and membrane fouling.In this study,the separation of S^0 from bulk liquids was performed using flocculation.Polyaluminum chloride（PAC）,polyacrylamide（PAM）and microbial flocculant（MBF）were compared to investigate their abilities to flocculate S^0 produced during the treatment of sulfate-containing wastewater.A novel approach with response surface methodology（RSM）was employed to evaluate the effects and interactions of flocculant dose,pH and stirring intensity,on the treatment efficiency in terms of the S^0 flocculation and the supernatant turbidity removal.The dose optimization results indicated that the S^0 flocculation efficiency decreased in the following order PAC〉MBF〉PAM.Optimum S^0 flocculation conditions were observed at pH 4.73,a stirring speed of 129 r/min and a flocculant dose of 2.42 mg PAC/mg S.During optimum flocculation conditions,the S^0f locculation rate reached 97.53%.Confirmation experiments demonstrated that employing PAC for S^0 flocculation is feasible and RSM is an efficient approach for optimizing the process of S^0 flocculation.The results provide basic parameters and conditions for recovering sulfur during the treatment of sulfate-laden wastewaters.

An integrated flexible and reusable graphene field effect transistor nanosensor for monitoring glucose

Diabetes is a chronic metabolic disease that has effect on blood sugar level and affects millions of people.We present an integrated flexible and reusable graphene-based field effect transistor(GFET)nanosensor for the detection of glucose using pyrene-1-boronic acid(PBA)as the receptor.The nanosensor fabricated on the polyimide performs GFET-based rapid transduction of the glucose-PBA binding,thereby potentially allowing the detection of glucose that are sampled reliably from human bodily fluids(e.g.,sweat)in wearable sensing applications.Due to the reversible binding interaction between PBA and glucose,reusability of our nanosensor can be realized by exposing graphene surface to acidic solution.In characterizing the stability and reusability of the nanosensor for wearable applications,we investigated the effects of substrate bending,multiple reuse and long-time storage on the equilibrium dissociation constant between the PBA and glucose.Results show that bending,multiple reuse(over 10 times)and long-time storage has negligible effect on the sensing performance.The detection of glucose with a limit of detection(LOD)of 0.15 μM and a dynamic range of 0.05-100 μM,which covers the reference scope of physical examination or screening of diabetes.Hence,our flexible GFET nanosensor is promising for wearable and reusable biosensing applications.

A robust reporting system for measurement of SARS-CoV-2 spike fusion efficiency

Dear Editor,During the COVID-19 pandemic,several SARS-CoV-2 variants such as Alpha,Delta,and Omicron successively became dominant worldwide.The infection of SARS-CoV-2 is triggered by the binding of spike protein to the cell-surface receptor angiotensinconverting enzyme 2(ACE2),which then fuses with cell membrane or lysosomal membrane after endocytosis.1 Extensive cell fusion and syncytia formation are a signature feature of severe SARS-CoV-2 and may play an important role in COVID-19 pathogenesis.Research has shown that SARS-CoV-2 spikemediated cell fusion leads to the formation of abnormal and multinucleated cells in the lungs of patients.2 Accordingly,the fusion ability of SARS-CoV-2 spike protein may be a leading indicator of viral infectivity and disease severity in SARS-CoV-2 patients.