Tandem hydroalkylation and deoxygenation of lignin-derived phenolics to synthesize high-density fuels

Lignin is the most abundant naturally phenolic biomass,and the synthesis of high-performance renewable fuel from lignin has attracted significant attention.We propose the efficient synthesis of high-density fuels using simulated lignin cracked oil in tandem with hydroalkylation and deoxygenation reactions.First,we investigated the reaction pathway for the hydroalkylation of phenol,which competes with the hydrodeoxygenation form cyclohexane.And then,we investigated the effects of metal catalyst types,the loading amount of metallic,acid dosage,and reactant ratio on the reaction results.The phenol hydroalkylation and hydrodeoxygenation were balanced when 180℃ and 5 MPa H_(2)with the alkanes yield of 95%.By extending the substrate to other lignin-derived phenolics and simulated lignin cracked oil,we obtained the polycyclic alkane fuel with high density of 0.918 g·ml^(-1)and calorific value of41.2 MJ·L^(-1).Besides,the fuel has good low-temperature properties(viscosity of 9.3 mm^(2)·s^(-1)at 20℃ and freezing point below-55℃),which is expected to be used as jet fuel.This work provides a promising way for the easy and green production of high-density fuel directly from real lignin oil.

Kinetic-Thermodynamic Promotion Engineering toward High-Density Hierarchical and Zn-Doping Activity-Enhancing ZnNiO@CF for High-Capacity Desalination

Despite the promising potential of transition metal oxides(TMOs)as capacitive deionization(CDI)electrodes,the actual capacity of TMOs electrodes for sodium storage is significantly lower than the theoretical capacity,posing a major obstacle.Herein,we prepared the kinetically favorable Zn_(x)Ni_(1−x)O electrode in situ growth on carbon felt(Zn_(x)Ni_(1−x)O@CF)through constraining the rate of OH^(−)generation in the hydrothermal method.Zn_(x)Ni_(1−x)O@CF exhibited a high-density hierarchical nanosheet structure with three-dimensional open pores,benefitting the ion transport/electron transfer.And tuning the moderate amount of redox-inert Zn-doping can enhance surface electroactive sites,actual activity of redox-active Ni species,and lower adsorption energy,promoting the adsorption kinetic and thermodynamic of the Zn_(0.2)Ni_(0.8)O@CF.Benefitting from the kinetic-thermodynamic facilitation mechanism,Zn_(0.2)Ni_(0.8)O@CF achieved ultrahigh desalination capacity(128.9 mgNaCl g^(-1)),ultra-low energy consumption(0.164 kW h kgNaCl^(-1)),high salt removal rate(1.21 mgNaCl g^(-1) min^(-1)),and good cyclability.The thermodynamic facilitation and Na^(+)intercalation mechanism of Zn_(0.2)Ni_(0.8)O@CF are identified by the density functional theory calculations and electrochemical quartz crystal microbalance with dissipation monitoring,respectively.This research provides new insights into controlling electrochemically favorable morphology and demonstrates that Zn-doping,which is redox-inert,is essential for enhancing the electrochemical performance of CDI electrodes.

Serum cystatin C,monocyte/high-density lipoprotein-C ratio,and uric acid for the diagnosis of coronary heart disease and heart failure

BACKGROUND Coronary heart disease(CHD)and heart failure(HF)are the major causes of morbidity and mortality worldwide.Early and accurate diagnoses of CHD and HF are essential for optimal management and prognosis.However,conventional diagnostic methods such as electrocardiography,echocardiography,and cardiac biomarkers have certain limitations,such as low sensitivity,specificity,availability,and cost-effectiveness.Therefore,there is a need for simple,noninvasive,and reliable biomarkers to diagnose CHD and HF.AIM To investigate serum cystatin C(Cys-C),monocyte/high-density lipoprotein cholesterol ratio(MHR),and uric acid(UA)diagnostic values for CHD and HF.METHODS We enrolled 80 patients with suspected CHD or HF who were admitted to our hospital between July 2022 and July 2023.The patients were divided into CHD(n=20),HF(n=20),CHD+HF(n=20),and control groups(n=20).The serum levels of Cys-C,MHR,and UA were measured using immunonephelometry and an enzymatic method,respectively,and the diagnostic values for CHD and HF were evaluated using receiver operating characteristic(ROC)curve analysis.RESULTS Serum levels of Cys-C,MHR,and UA were significantly higher in the CHD,HF,and CHD+HF groups than those in the control group.The serum levels of Cys-C,MHR,and UA were significantly higher in the CHD+HF group than those in the CHD or HF group.The ROC curve analysis showed that serum Cys-C,MHR,and UA had good diagnostic performance for CHD and HF,with areas under the curve ranging from 0.78 to 0.93.The optimal cutoff values of serum Cys-C,MHR,and UA for diagnosing CHD,HF,and CHD+HF were 1.2 mg/L,0.9×10^(9),and 389μmol/L;1.4 mg/L,1.0×10^(9),and 449μmol/L;and 1.6 mg/L,1.1×10^(9),and 508μmol/L,respectively.CONCLUSION Serum Cys-C,MHR,and UA are useful biomarkers for diagnosing CHD and HF,and CHD+HF.These can provide information for decision-making and risk stratification in patients with CHD and HF.

Conversion of lignin oil and hemicellulose derivative into high-density jet fuel

Synthesizing high-density fuel from lignocellulose can not only achieve green and low-carbon development,but also expand the feedstock source of hydrocarbon fuel.Here,we reported a route of producing high-density fuel from lignin oil and hemicellulose derivative cyclopentanol through alkylation and hydrodeoxygenation,HY with SiO_(2)/Al_(2)O_(3) molar ratio of 5.3 was screened as the alkylation catalyst in the reaction of model phenolic compounds and mixtures,and the reaction conditions were optimized to achieve conversion of phenolic compounds higher than 87%and selectivity of bicyclic and tricyclic products higher than 99%.Then two phenolic pools simulating the composition of two typic lignin oils were studied to validate the alkylation and analyze the competition mechanism of phenolic compounds in mixture system.Finally,real lignin oil from depolymerized of beech powder was tested,and notably80%of phenolic monomers in the oil were converted into fuel precursor.After hydrodeoxygenation,the alkylated product was converted to fuel blend with a density of 0.91 g/mL at 20℃and a freezing point lower than-60℃,very promising as high density fuel.This work provides a facile and energyefficient way of synthesizing high-performance jet fuel directly from lignocellulosic derivatives,which decreases processing energy consumption and improve the utilization rate of feedstock.

QTL mapping for berry shape based on a high-density genetic map constructed by whole-genome resequencing in grape

Grape berry shape is an important agricultural trait.Clarifying its genetic basis is significant for cultivating grape varieties that meet market demands.However,the current study by forward genetics has not achieved in-depth results.Here,a high-density map was constructed to identify quantitative trait loci(QTLs)for berry shape.A total of 358709 polymorphic SNPs were obtained using whole-genome resequencing(WGS)based on 208 F2 individuals derived from round grape‘E42-6’and oblong grape‘Rizamat’.The 1635.65 cM high-density map was divided into 19 linkage groups with an average distance of 0.37 cM.Using this map,three significant QTLs for fruit shape index(ShI:ratio of berry length to berry width)identified over three years were mapped onto LG4 and LG5,including one stable QTL on Chr5 with the genomic region of 0.47–1.94 Mb.Combining with gene annotation and expression patterns based on RNA-seq data from two contrasting F2 individuals with round and oblong berry(their average ShI was 1.89 and 1.10,respectively)at four developmental stages,four candidate genes were selected from the above QTLs.They were mainly involved in DNA replication,cell wall modification,and phytohormone biosynthesis.Further analysis of RNA-seq data revealed that several important phytohormone synthesis and metabolic pathways were enriched based on differentially expressed genes(DEGs),which was consistent with the results of QTL mapping for genes related to plant hormone biosynthesis in the F2 population.Furthermore,a comparison of plant hormone content showed that there were significant differences in IAA and tZ content between the two contrasting F2 individuals at different developmental stages.Our findings provide molecular insights into the genetic variation in grape berry shape.Stable QTLs and their tightly linked markers offer the possibility of marker-assisted selection to accelerate berry shape breeding.

Fine‑tuning genomic and pedigree inbreeding rates in equine population with a deep and reliable stud book:the case of the Pura Raza Española horse

Background:Estimating inbreeding,which is omnipresent and inevitable in livestock populations,is a primary goal for management and animal breeding especially for those interested in mitigating the negative consequences of inbreeding.Inbreeding coefficients have been historically estimated by using pedigree information;however,over the last decade,genome-base inbreeding coefficients have come to the forefront in this field.The Pura Raza Espanola(PRE)horse is an autochthonous Spanish horse breed which has been recognised since 1912.The total PRE population(344,718 horses)was used to estimate Classical(F),Ballou’s ancestral,Kalinowski’s ancestral,Kalinowski’s new and the ancestral history coefficient values.In addition,genotypic data from a selected population of 805 PRE individuals was used to determine the individual inbreeding coefficient using SNP-by-SNP-based techniques(methods of moments-FHOM-,the diagonal elements of the genomic-FG-,and hybrid matrixes-FH-)and ROH measures(FRZ).The analyse of both pedigree and genomic based inbreeding coefficients in a large and robust population such as the PRE horse,with proven parenteral information for the last 40 years and a high degree of completeness(over 90%for the last 70 years)will allow us to understand PRE genetic variability better and the correlations between the estimations will give the data greater reliability.Results:The mean values of the pedigree-based inbreeding coefficients ranged from 0.01(F for the last 3 generations-F3-)to 0.44(ancestral history coefficient)and the mean values of genomic-based inbreeding coefficients varied from 0.05(FRZ for three generations,FH and FHOM)to 0.11(FRZ for nine generations).Significant correlations were also found between pedigree and genomic inbreeding values,which ranged between 0.58(F3 with FHOM)and 0.79(F with FRZ).In addition,the correlations between FRZ estimated for the last 20 generations and the pedigree-based inbreeding highlight the fact that fewer generations of genomic data are required when comparing total inbreeding values,and the opposite when ancient values are calculated.Conclusions:Ultimately,our results show that it is still useful to work with a deep and reliable pedigree in pedigreebased genetic studies with very large effective population sizes.Obtaining a satisfactory parameter will always be desirable,but the approximation obtained with a robust pedigree will allow us to work more efficiently and economically than with massive genotyping.

Monitoring Study of Long-Term Land Subsidence during Subway Operation in High-Density Urban Areas Based on DInSAR-GPS-GIS Technology and Numerical Simulation

During subway operation,various factors will cause long-term land subsidence,such as the vibration subsidence of foundation soil caused by train vibration load,incomplete consolidation deformation of foundation soil during tunnel construction,dense buildings and structures in the vicinity of the tunnel,and changes in water level in the stratum where the tunnel is located.The monitoring of long-term land subsidence during subway operation in high-density urban areas differs from that in low-density urban construction areas.The former is the gathering point of the entire urban population.There are many complex buildings around the project,busy road traffic,high pedestrian flow,and less vegetation cover.Several existing items requiremonitoring.However,monitoring distance is long,and providing early warning is difficult.This study uses the 2.8 km operation line between Wulin Square station and Ding’an Road station of Hangzhou Subway Line 1 as an example to propose the integrated method of DInSAR-GPS-GIS technology and the key algorithm for long-term land subsidence deformation.Then,it selects multiscene image data to analyze long-termland subsidence of high-density urban areas during subway operation.Results show that long-term land subsidence caused by the operation of Wulin Square station to Ding’an Road station of Hangzhou Subway Line 1 is small,with maximumsubsidence of 30.64 mm,and minimumsubsidence of 11.45 mm,and average subsidence ranging from 19.27 to 21.33 mm.And FLAC3D software was used to verify the monitoring situation,using the geological conditions of the soil in the study area and the tunnel profile to simulate the settlement under vehicle load,and the simulation results tended to be consistent with the monitoring situation.

Identification of the dominant loop of a dual-loop macro-reentry left atrial flutter without prior intervention using high-density mapping technology:A case report

BACKGROUND Left atrial flutter without prior cardiac interventions is uncommon,especially dual-loop macro-reentry atrial flutter.The critical step to ablate dual-loop macroreentry atrial flutter is to identify the dominant loop and key isthmus.Although entrainment mapping could help identify the dominant loop and key isthmus,it may alter or terminate tachycardia.High-density mapping allows the generation of electroanatomic maps without altering or terminating tachycardia.CASE SUMMARY Here,we report a case of symptomatic left atrial flutter without prior intervention.In this case,high-density mapping revealed a dual-loop macro-reentry around the mitral annulus and central scar of the anterior wall.The propagation result showed that the dominant loop was around the mitral annulus,and the key isthmus was between the central scar and mitral annulus.The atrial flutter terminated successfully after ablation was performed.CONCLUSION In this case,we demonstrate that high-density mapping technology may help identify the dominant loop of dual-loop atrial flutter without entrainment,which makes ablation easier.

Research and Application of High-Density Resistivity Method in Seawater Intrusion Investigation in Laizhou Bay

The disaster of seawater intrusion seriously affects people's lives and restricts economic development,so the detection and treatment of seawater intrusion is a long-term task.On the basis of field investigation and water quality analysis,according to the change characteristics of apparent resistivity of groundwater after Cl-reaches 250 mg/L,the theoretical basis for the application of high-density resistivity method was determined,and the characteristic values of apparent resistivity for seawater intrusion interfaces in different geological characteristic regions in Laizhou Bay area were determined by typical profile tests.Combined with water quality investigation and other means,profiles for the high-density resistivity method were arranged,and the interfaces between saline and fresh water were accurately divided.

Pedigree tracing of Fenneropenaeus chinensis by microsatellite DNA markers genotyping

Two microsateUite DNA loci were used to trace the pedigree structure of six families in the shrimp Fenneropenaeus chinensis. Four of the families were natural mating, and the others were mated by artificial insemination. Eleven alleles were acquired at two microsatellite DNA loci （locus RS0622 and locus EN0033 ） by investigating 145 offsprings and 11 parents. Five alleles were acquired from locus RS0622 and six from locus EN0033. As analyzed, the gene frequencies were between 0. 024 1 and 0. 493 1, the heterozygosity was 0.652 2 and 0.688 8, and the polymorphism information content （PIC） was 0.585 7 and 0.652 9 for the locus RS0622 and the locus EN0033, respectively. Twenty-three genotypes were detected and the genotypes of the losing parents were also inferred. The pedigrees of three F1 and three F2 generations were determined by matching the genotype at each locus.

OCCURRENCE CHARACTERISTIC OF KASHIN-BECK DISEASE BASED ON NUCLEAR FAMILY PEDIGREES

Objective The occurrence characteristic of Kashin Beck Disease (KBD) in pedigrees ascertained on the basis of one proband was estimated. Methods A total of 255 individuals in 40 pedigrees were collected from areas in the Shaanxi Province. Results ① Parents and siblings of index cases have a 3-4 times higher risk than a random unrelated individual. The odds ratio for disease is higher in mothers than in fathers of index cases; ② Prevalence in relatives of index cases (K r= 59.2% ) greatly exceeds population prevalence (K= 17.5% ); ③ K r increases with sibship size; ④ There is no significant difference of K r for male and female siblings of index cases. Also, population prevalence is not sex specific. Conclusion In conjunction with environmental agents, genetics may play an important role in KBD etiology.

Development of Genomic Microsatellite Multiplex PCR Using Dye-Labeled Universal Primer and Its Validation in Pedigree Analysis of Pacific Oyster(Crassostrea gigas)

There is an increasing requirement for traceability of aquaculture products, both for consumer protection and for food safety. There are high error rates in the conventional traceability systems depending on physical labels. Genetic traceability technique depending on DNA-based tracking system can overcome this problem. Genealogy information is essential for genetic traceability, and microsatellite DNA marker is a good choice for pedigree analysis. As increasing genotyping throughput of microsatellites, microsatellite multiplex PCR has become a fast and cost-effective technique. As a commercially important cultured aquatic species, Pacific oyster Crassostrea gigas has the highest global production. The objective of this study was to develop microsatellite multiplex PCR panels with dye-labeled universal primer for pedigree analysis in C. gigas, and these multiplex PCRs were validated using 12 full-sib families with known pedigrees. Here we developed six informative multiplex PCRs using 18 genomic microsatellites in C. gigas. Each multiplex panel contained a single universal primer M13(-21) used as a tail on each locus-specific forward primer and a single universal primer M13(-21) labeled with fluorophores. The polymorphisms of the markers were moderate, with an average of 10.3 alleles per locus and average polymorphic information content of 0.740. The observed heterozygosity per locus ranged from 0.492 to 0.822. Cervus simulations revealed that the six panels would still be of great value when massive families were analysed. Pedigree analysis of real offspring demonstrated that 100% of the offspring were unambiguously allocated to their parents when two multiplex PCRs were used. The six sets of multiplex PCRs can be an important tool for tracing cultured individuals, population genetic analysis, and selective breeding program in C. gigas.

High-density lipoprotein and atherosclerosis: Roles of lipid transporters

Various previous studies have found a negative cor-relation between the risk of cardiovascular events and serum high-density lipoprotein(HDL) cholesterol levels. The reverse cholesterol transport, a pathway of choles-terol from peripheral tissue to liver which has several potent antiatherogenic properties. For instance, the particles of HDL mediate to transport cholesterol from cells in arterial tissues, particularly from atherosclerotic plaques, to the liver. Both ATP-binding cassette trans-porters(ABC) A1 and ABCG1 are membrane cholesterol transporters and have been implicated in mediating cholesterol effluxes from cells in the presence of HDL and apolipoprotein A-I, a major protein constituent of HDL. Previous studies demonstrated that ABCA1 and ABCG1 or the interaction between ABCA1 and ABCG1 exerted antiatherosclerotic effects. As a therapeutic approach for increasing HDL cholesterol levels, much focus has been placed on increasing HDL cholesterol levels as well as enhancing HDL biochemical functions. HDL therapies that use injections of reconstituted HDL, apoA-I mimetics, or full-length apoA-I have shown dramatic effectiveness. In particular, a novel apoA-I mi-metic peptide, Fukuoka University ApoA-I Mimetic Pep-tide, effectively removes cholesterol via specific ABCA1 and other transporters, such as ABCG1, and has an an-tiatherosclerotic effect by enhancing the biological func-tions of HDL without changing circulating HDL choles-terol levels. Thus, HDL-targeting therapy has significant atheroprotective potential, as it uses lipid transporter-targeting agents, and may prove to be a therapeutic tool for atherosclerotic cardiovascular diseases.

High-resolution crustal velocity imaging using ambient noise recordings from a high-density seismic array:An example from the Shangrao section of the Xinjiang basin,China

A profile of shallow crustal velocity structure(1–2 km) may greatly enhance interpretation of the sedimentary environment and shallow tectonic deformation.Recent advances in surface wave tomography, using ambient noise data recorded with high-density seismic arrays, have improved the understanding of regional crustal structure. As the interest in detailed shallow crustal structure imaging has increased, dense seismic array methods have become increasingly efficient. This study used a high-density seismic array deployed in the Xinjiang basin in southeastern China, to record seismic data, which was then processed with the ambient noise tomography method. The high-density seismic array contained 203 short-period seismometers, spaced at short intervals(～ 400 m). The array collected continuous records of ambient noise for 32 days. Data preprocessing,cross correlation calculation, and Rayleigh surface wave phase-velocity dispersion curve extraction, yielded more than 16,000 Rayleigh surface wave phase-velocity dispersion curves, which were then analyzed using the direct-inversion method. Checkerboard tests indicate that the shear wave velocity is recovered in the study area, at depths of 0–1.4 km,with a lateral image resolution of ～ 400 m. Model test results show that the seismic array effectively images a 50 m thick slab at a depth of 0–300 m, a 150 m thick anomalous body at a depth of 300–600 m, and a 400 m thick anomalous body at a depth of 0.6–1.4 km. The shear wave velocity profile reveals features very similar to those detected by a deep seismic reflection profile across the study area. This demonstrates that analysis of shallow crustal velocity structure provides high-resolution imaging of crustal features.Thus, ambient noise tomography with a high-density seismic array may play an important role in imaging shallow crustal structure.

Effect of low high-density lipoprotein levels on mortality of septic patients: A systematic review and meta-analysis of cohort studies

BACKGROUND:An increase in high-density lipoprotein(HDL)is well associated with a decreased cardiovascular risk,especially atherosclerosis.Recent studies suggest that lower levels of HDL may also be associated with an increased risk of sepsis and an increased rate of mortality in septic patients.However,this conclusion remains controversial.METHODS:MEDLINE,EMBASE,and CENTRAL databases were searched from inception to September 30,2019.All studies were conducted to evaluate the correlation of lipoprotein levels and the risk and outcomes of sepsis in adult patients.The primary outcomes were the risk and mortality of sepsis.RESULTS:Seven studies comprising 791 patients were included.Lower levels of HDL had no marked relevance with the risk of sepsis(odds radio[OR]for each 1 mg/dL increase,0.94;95%CI 0.86–1.02;P=0.078),whereas lower HDL levels were related to an increased mortality rate in septic patients(OR for below about median HDL levels,2.00;95%CI 1.23–3.24;P=0.005).CONCLUSION:This meta-analysis did not reveal a signifi cant association between lower HDL levels and an increase in the risk of sepsis,whereas it showed that lower HDL levels are associated with a higher mortality rate in septic adult patients.These findings suggest that HDL may be considered as a promising factor for the prevention and treatment of sepsis in the future.

Genetic relationship and pedigree of Chinese watermelon varieties based on diversity of perfect SNPs

Watermelon(Citrullus lanatus)is one of the world’s most important fruit crops,and China produces the most watermelons in the world.Recently,a watermelon variome consisting of 414 key resequenced accessions was reported.However,the genetic relationships and pedigree of Chinese watermelon varieties in the seed market remain unclear.In this study,241 evenly distributed perfect single nucleotide polymorphisms(SNPs)derived from the watermelon variome were selected for variety identification.The diversity of 247 Chinese watermelon varieties was identified based on their SNP genotypes.The 247 watermelon varieties were clustered into five subpopulations:the East Asian ecotype,intermediate ecotype,small fruit with red flesh ecotype,small fruit with yellow flesh ecotype,and American ecotype.We further established the pedigree of four subpopulations,of which JingXinNo.1,ZaoChunHongYu,HuangXiaoYu and XiaoLan,and Sugarlee were the main doner of the East Asian ecotype,small fruit with red flesh ecotype,small fruit with yellow flesh ecotype,and American ecotype,respectively.Thirty-two core SNPs were selected and applied in watermelon variety identification.They were also validated by the Kompetitive allele-specific PCR(KASPar)platform.The present study furthered our understanding of the genetic relationships and pedigree of watermelon varieties in China,and will help to manage the plant variety protection in watermelon.

Proso Millet Protein Elevates Plasma Level of High-Density Lipoprotein:A New Food Function of Proso Millet

We examined the effects of dietary proso-millet protein on plasma levels of high-density lipoprotein (HDL) cholesterol in different rats from animals reported in our previous studies. The results showed also, in this animal, that the ingestion of the millet protein elevates plasma levels of HDL-cholesterol like our earlier works. Taking into account the anti-atherogenic function of HDL, therefore, the millet protein would be useful as a new food ingredient which has the function that regulates cholesterol metabolism

POPULATION CHARACTERS IN HIGH RISK PEDIGREES OFNASOPHARYNGEAL CARCINOMA (NPC)

Objective: To investigate population characters in high risk pedigrees of NPC in Guangdong area and to explore the effect each other between tumor genetic susceptibility and infection of EB virus on pathogenic mechanism. Methods: Pedigree investigation, examination of DNA fingerprint, multi-antibodies of EB virus and nasopharyngeal cavity were done for all of the members in each high risk pedigree. Results: High positive rate of EBV VCA/IgA (23.22%), high percentage of high risk population of NPC (6.53–10.40%), high detected rate of malignant tumor (9552.59/105), and high detected rate of NPC (8464.32/105) were discovered and NPC was most common in first degree relative of a pedigree. Conclusion: Tumor genetic susceptibility, infection of EB virus might play a role in coordination of reinforced effect on occurrence of NPC.

Studies of a pedigree with limbal dermoid cyst

AIM: To study clinical features and gene mutations within the paired-like homeodomain transcription factor 2 (PITX2) gene in a pedigree of bilateral limbal dermoids. METHODS: Complete eye examinations have been performed on each individual of the family. Exons of paired-like homeodomain transcription factor 2 ( PITX2)were amplified by polymerase chain reaction, sequenced, and compared with a reference database. RESULTS: We described the phenotype, clinic findings in a family with two affected members. The masses of the proband's eyes were excised surgically demonstrating a dermoid cyst by histopathological examination. No mutation was detected in the gene PITX2 in this pedigree. CONCLUSION: A family of limbal dermoid cyst was reported. In addition, no pathogenic sequence variations were found in PITX2, indicating that this phenotype in this family is a distinctive entity.

Expression and Purification of Recombinant Hepatitis Delta Virus(HDV) Antigen for Use in a Diagnostic ELISA for HDV Infection Using the High-Density Fermentation Strategy in Escherichia coli

Objective Hepatitis Delt a Virus（HDV） antigen is widely used as a capture antigen in ELISAs for the identification of HDV infection; large amounts of recombinant HDV antigen with active antigenicity are required for this purpose. Methods Reconstruct the gene of HDV antigen based on the bias code of Escherichia coli, the recombinant protein expresses by high-density fermentation with fed-batch feeding strategy, and purify by immobilized metal chromatography. The sensitivity and specificity of this antigen detect by ELISA method. Results The expression of HDV antigen can reach 20% of the total cell mass in the soluble form. The recombinant HDV antigen can be conveniently purified（98%） by immobilized metal ion affinity chromatography（IMAC） using the interaction between a His-tag and nickel ions. Production of recombinant HDV antigen can reach 0.5 g/L under conditions of high-density cell fermentation. Applied to the diagnostic ELISA method, the recombinant HDV antigen shows excellent sensitivity（97% for IgM and 100% for IgG） and specificity（100% for IgG and IgM） for the detection of anti-HDV antibodies. Conclusion Expression and purification the recombinant HDV antigen as a candidate protein for application in a diagnostic ELISA for HDV infection. Large-scale production of the protein can be achieved using the high-density fermentation strategy.