Proteomics Platform Reveals Broad-Spectrum Nanobodies for SARS-CoV-2 Variant Neutralization.

The ongoing evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to the emergence of different variants of concerns with immune evasion that have been prevalent over the past three years. Nanobodies, the functional variable regions of camelid heavy-chain-only antibodies, have garnered interest in developing neutralizing antibodies due to their smaller size, structural stability, ease of production, high affinity, and low immunogenicity, among other characteristics. In this work, we describe an integrated proteomics platform for the high-throughput screening of nanobodies against different SARS-CoV-2 spike variants. To demonstrate this platform, we immunized a camel with subunit 1 (S1) of the wild-type spike protein and constructed a nanobody phage library. The binding and neutralizing activities of the nanobodies against 72 spike variants were then measured, resulting in the identification of two nanobodies (C-282 and C-39) with broad neutralizing activity against six non-Omicron variants (D614G, Alpha, Beta, Gamma, Delta, Kappa) and five Omicron variants (BA.1-5). Their neutralizing capability was validated using in vitro pseudovirus-based neutralization assays. All these results demonstrate the utility of our proteomics platform to identify new nanobodies with broad neutralizing capability and to develop a treatment for patients with SARS-CoV-2 variant infection in the future.

Optimization of terminal area arrival flight sorting based on an improved sparrow search algorithm.

At present, airspace congestion and flight delays have become widespread concerns. This study aims to optimize the sequencing of arrival flights in the terminal area of multirunway airports. Considering the constraints of multiple runways, slant intervals and moving flight positions, this article establishes an optimization model for arrival flight sequencing in a multirunway airport terminal area. Accordingly, an improved sparrow search algorithm (ISSA) is proposed based on Chebyshev chaotic mapping, the golden sine strategy, and the variable neighborhood strategy. Through six basic test functions, the ISSA is compared with particle swarm optimization, the whale optimization algorithm, the genetic algorithm, and other algorithms to verify its superiority. Finally, two sets of instance data from Kunming Changshui Airport were used for experiments. The results show that the total delay times (TDTs) of small-scale flights (number of aircraft: 29) and large-scale flights (number of aircraft: 147) are 55.3% and 20.5% lower, respectively, than those of the first-come-first-served algorithm. The superiority of the ISSA designed in this article is verified, and it can significantly reduce the TDTs of arrival flights. It is suitable for optimizing arrival flights during peak hours at most airports. This approach provides theoretical support for optimizing the sorting of flights in terminal areas.

Antibody Profiling of Pan-Cancer Viral Proteome Reveals Biomarkers for Nasopharyngeal Carcinoma Diagnosis and Prognosis.

Diagnosing, predicting disease outcome, and identifying effective treatment targets for virus-related cancers are lacking. Protein biomarkers have the potential to bridge the gap between prevention and treatment for these types of cancers. While it has been shown that certain antibodies against EBV proteins could be used to detect nasopharyngeal carcinoma (NPC), antibodies targeting are solely a tiny part of the about 80 proteins expressed by the EBV genome. Furthermore, it remains unclear what role other viruses play in NPC since many diseases are the result of multiple viral infections. For the first time, this study measured both IgA and IgG antibody responses against 646 viral proteins from 23 viruses in patients with NPC and control subjects using nucleic acid programmable protein arrays. Candidate seromarkers were then validated by ELISA using 1665 serum samples from three clinical cohorts. We demonstrated that the levels of five candidate seromarkers (EBV-BLLF3-IgA, EBV-BLRF2-IgA, EBV-BLRF2-IgG, EBV-BDLF1-IgA, EBV-BDLF1-IgG) in NPC patients were significantly elevated than controls. Additional examination revealed that NPC could be successfully diagnosed by combining the clinical biomarker EBNA1-IgA with the five anti-EBV antibodies. The sensitivity of the six-antibody signature at 95% specificity to diagnose NPC was comparable to the current clinically-approved biomarker combination, VCA-IgA, and EBNA1-IgA. However, the recombinant antigens of the five antibodies are easier to produce and standardize compared to the native viral VCA proteins. This suggests the potential replacement of the traditional VCA-IgA assay with the 5-antibodies combination to screen and diagnose NPC. Additionally, we investigated the prognostic significance of these seromarkers titers in NPC. We showed that NPC patients with elevated BLLF3-IgA and BDLF1-IgA titers in their serum exhibited significantly poorer disease-free survival, suggesting the potential of these two seromarkers as prognostic indicators of NPC. These findings will help develop serological tests to detect and treat NPC in the future.

Profiling of SARS-CoV-2 neutralizing antibody-associated antigenic peptides signature using proteome microarray.

The profile of antibodies against antigenic epitopes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during neutralizing antibody (NAb) decay has not been clarified. Using a SARS-CoV-2 proteome microarray that contained viral antigenic peptides, we analyzed the characteristics of the humoral response in patients with coronavirus disease 19 (COVID-19) in a longitudinal study. A total of 89 patients were recruited, and 226 plasma samples were serially collected in 2020. In the antigenic peptide microarray, the level of immunoglobulin G (IgG) antibodies against peptides within the S2 subunit (S-82) and a conserved gene region in variants of interest, open reading frame protein 10 (ORF10-3), were closely associated with the presence of SARS-CoV-2 NAbs. In an independent evaluation cohort of 232 plasma samples collected from 116 COVID-19 cases in 2020, S82-IgG titers were higher in NAbs-positive samples (p = 0.002) than in NAbs-negative samples using enzyme-linked immunosorbent assay. We further collected 66 plasma samples from another cohort infected by Omicron BA.1 virus in 2022. Compared with the samples with lower S82-IgG titers, NAb titers were significantly higher in the samples with higher S82-IgG titers (p = 0.04). Our findings provide insights into the understanding of the decay-associated signatures of SARS-CoV-2 NAbs.

Constructing an Ensemble Model and Niche Comparison for the Management Planning of Eucalyptus Longhorned Borer Phoracantha semipunctata under Climate Change.

Phoracantha semipunctata is a destructive invasive alien forest pest worldwide. It primarily damages the eucalyptus via adults, affecting almost all parts of the eucalyptus. Its larvae develop in almost all major tissues of the plant. Phoracantha semipunctata spreads both via the migration of adults and global trade in intercontinental translocation. Currently, this pest has spread to six continents worldwide, except Antarctica, resulting in substantial economic losses. Based on global occurrence data and environmental variables, the potential global geographical distribution of P. semipunctata was predicted using an ensemble model. The centroid shift, overlap, unfilling, and expansion scheme were selected to assess niche dynamics during the global invasion process. Our results indicated that the AUC and TSS values of the ensemble model were 0.993 and 0.917, respectively, indicating the high prediction accuracy of the model. The distribution pattern of P. semipunctata is primarily attributed to the temperature seasonality (bio4), mean temperature of the warmest quarter (bio10), and human influence index variables. The potential geographical distribution of P. semipunctata is primarily in western and southwestern Asia, western Europe, western and southern North America, southern South America, southern Africa, and eastern and southern Oceania. The potential geographical distribution of P. semipunctata showed a downward trend in the 2030s and the 2050s. The distribution centroid showed a general tendency to shift southward from the near-current to future climate. Phoracantha semipunctata has largely conserved its niche during the global invasion process. More attention should be paid to the early warning, prevention, and control of P. semipunctata in the countries and regions where it has not yet become invasive.

Atomistic insights into migration mechanism of graphene-based membranes on soil mineral phases.

Graphene-based membranes (GBM) will migrate in the soil and enter the groundwater system or plant roots, which will eventually pose potential risks to human beings. The migration mechanism of GBM depends on the interface behavior of complex soil components. Herein, we use molecular dynamics (MD) simulations to probe the interface behavior between GBM and three type minerals (quartz, calcite and kaolinite). Based on the investigation of binding energy, maximum pulling force and barrier energy, the order of the difficulty of GBM adsorption and desorption on the three minerals from small to large is roughly: quartz, calcite and kaolinite respectively. The graphene-oxide (GO), improves the binding energy and energy barrier, making GBM difficult to migrate in soil. Remarkably, a larger GBM sheet and high velocity external load improve GBM migration in soil to a certain extent. These investigations give the dynamic information on the GBM/mineral interaction and provide nanoscale insights into the migration mechanisms of GBM in soil.

Proteomics Landscape Mapping of Organ-Resolved Behçet's Disease Using In-Depth Plasma Proteomics for Identifying Hyaluronic Binding Protein 2 Expression Associated With Vascular Involvement.

OBJECTIVE: This study was undertaken to elucidate the pathogenesis and heterogeneity of Behçet's disease (BD) involving different organs using in-depth proteomics to identify the biomarkers for clinical assessment and treatment of patients with BD. METHODS: We measured the expression levels of proteins in plasma samples from 98 patients with BD and from 31 healthy controls using our in-depth proteomics platform with a data-independent acquisition mass spectrometer and antibody microarray. We performed bioinformatics analyses of the biologic processes and signaling pathways that were changed in the BD group and constructed a proteomics landscape of organ-resolved BD pathogenesis. We then validated the biomarkers of disease severity and the vascular subset in an independent cohort of 108 BD patients and 29 healthy controls using an enzyme-linked immunosorbent assay. RESULTS: The BD group had 220 differentially expressed proteins, which discriminated between BD patients (88.6%) and healthy controls (95.5%). The bioinformatics analyses revealed different biologic processes associated with BD pathogeneses, including complement activation, wound healing, angiogenesis, and leukocyte-mediated immunity. Furthermore, the constructed proteomics landscape of organ-resolved BD identified proteomics features of BD associated with different organs and protein targets that could be used for the development of therapeutic treatment. Hyaluronic binding protein 2, tenascin, and serpin A3 were validated as potential biomarkers for the clinical assessment of vascular BD and treatment targets. CONCLUSION: Our results provide valuable insight into the pathogenesis of organ-resolved BD in terms of proteomics characteristics and potential biomarkers for clinical assessment and potential therapies for vascular BD.

Electrochemical Skin Conductance by Sudoscan in Non-Dialysis Chronic Kidney Disease Patients.

BACKGROUND: Peripheral neuropathy is prevalent among patients with chronic kidney disease (CKD). Sudoscan non-invasively detects polyneuropathy by measuring electrochemical skin conductance (ESC). We conducted a study on sudomotor function in CKD patients across various stages based on their estimated glomerular filtration rate (eGFR). METHODS: In this cross-sectional study of 700 CKD patients, all underwent Sudoscan. Pathological ESC was defined as hands < 40 µS or feet < 50 µS. Clinical neuropathy scores including Michigan Neuropathy Screening Instrument (MNSI) and Douleur Neuropathique en 4 questionnaire (DN4) were obtained. RESULTS: Among participants, 344 had diabetes and 356 did not. Hands and feet ESC decreased with CKD progression (median (IQR) in stage 1-2, 3, 4-5: 54.0 (39.0-68.0), 45.5 (30.0-63.0), 41.8 (26.5-60.5), p trend < 0.001; 64.5 (53.5-74.0), 60.5 (43.0-72.5), 55.0 (39.0-69.8), p trend < 0.001). Pathological hands and feet ESC increased in later CKD stages (stage 1-2, 3, 4-5: 26.6%, 40.9%, 45.7%, p trend < 0.001; 21.7%, 34.0%, 40.6%, p trend < 0.001). Positive hands and feet ESC-eGFR correlation existed irrespective of diabetes. Diabetic patients had lower hands and feet ESC than non-diabetics as CKD progressed. However, multivariate regression found no significant ESC-eGFR association. Sudoscan correlated with clinical neuropathy scores. CONCLUSION: Pathological sudomotor function was common in non-dialysis CKD stages 4-5. Diabetic patients had worse function. Sudomotor dysfunction progressed with renal disease but eGFR was not an independent risk factor.

SARS-CoV-2 Epitopes following Infection and Vaccination Overlap Known Neutralizing Antibody Sites.

Identification of epitopes targeted following virus infection or vaccination can guide vaccine design and development of therapeutic interventions targeting functional sites, but can be laborious. Herein, we employed peptide microarrays to map linear peptide epitopes (LPEs) recognized following SARS-CoV-2 infection and vaccination. LPEs detected by nonhuman primate (NHP) and patient IgMs after SARS-CoV-2 infection extensively overlapped, localized to functionally important virus regions, and aligned with reported neutralizing antibody binding sites. Similar LPE overlap occurred after infection and vaccination, with LPE clusters specific to each stimulus, where strong and conserved LPEs mapping to sites known or likely to inhibit spike protein function. Vaccine-specific LPEs tended to map to sites known or likely to be affected by structural changes induced by the proline substitutions in the mRNA vaccine's S protein. Mapping LPEs to regions of known functional importance in this manner may accelerate vaccine evaluation and discovery of targets for site-specific therapeutic interventions.

Association of serum fibroblast growth factor 21 levels with skeletal muscle mass and mortality in chronic hemodialysis patients.

BACKGROUND/PURPOSE: Fibroblast growth factor 21 (FGF21) is a hormone that modulates metabolic pathways, which acts as a myokine under metabolic stress. We aimed to explore the association of serum FGF21 levels with skeletal muscle mass and mortality in patients on hemodialysis (HD). METHODS: Baseline serum FGF21 levels were measured, and a portable whole-body bioelectrical impedance device was used to assess skeletal muscle mass. One hundred twenty-four patients undergoing chronic HD were categorized into high- and low-FGF21 groups according to the median FGF21 value. RESULTS: Patients with low FGF21 values had lower body weight, body mass index, skeletal muscle mass index (SMI = skeletal muscle mass/height2), and serum triglyceride levels. Log serum FGF21 levels revealed a modest but positive correlation with SMI (r = 0.30, p = 0.001) and independently predicted SMI after multiple adjustment (ß = 1.59, p = 0.027). During a median follow-up period of 66 months, all-cause mortality and cardiovascular death rates did not differ significantly between the high- and low-FGF21 groups. We also failed to demonstrate FGF21 as an independent predictor of all-cause mortality. CONCLUSION: Serum FGF21 levels exhibited a positive association with skeletal muscle mass but were not predictive of mortality in patients undergoing chronic HD.

Inhibitor screening using microarray identifies the high capacity of neutralizing antibodies to Spike variants in SARS-CoV-2 infection and vaccination.

Rationale: Mutations of SARS-CoV-2, which is responsible for coronavirus disease 2019 (COVID-19), could impede drug development and reduce the efficacy of COVID-19 vaccines. Here, we developed a multiplexed Spike-ACE2 Inhibitor Screening (mSAIS) assay that can measure the neutralizing effect of antibodies across numerous variants of the coronavirus's Spike (S) protein simultaneously. Methods: The SARS-CoV-2 spike variant protein microarrays were prepared by printing 72 S variants onto a chemically-modified glass slides. The neutralization potential of purified anti-S antibodies and serum from convalescent COVID-19 patients and vaccinees to S variants were assessed with the mSAIS assay. Results: We identified new S mutations that are sensitive and resistant to neutralization. Serum from both infected and vaccinated groups with a high titer of neutralizing antibodies (NAbs) displayed a broader capacity to neutralize S variants than serum with low titer NAbs. These data were validated using serum from a large vaccinated cohort (n = 104) with a tiled S peptide microarray. In addition, similar results were obtained using a SARS-CoV-2 pseudovirus neutralization assay specific for wild-type S and five prevalent S variants (D614G, B.1.1.7, B.1.351, P.1, B.1.617.2), thus demonstrating that high antibody diversity is associated with high NAb titers. Conclusions: Our results demonstrate the utility of the mSAIS platform in screening NAbs. Moreover, we show that heterogeneous antibody populations provide a more protective effect against S variants, which may help direct COVID-19 vaccine and drug development.

Longitudinal and proteome-wide analyses of antibodies in COVID-19 patients reveal features of the humoral immune response to SARS-CoV-2.

Introduction: The SARS-CoV-2 pandemic has endangered global health, the world economy, and societal values. Despite intensive measures taken around the world, morbidity and mortality remain high as many countries face new waves of infection and the spread of new variants. Worryingly, more and more variants are now being identified, such as 501Y.V1 (B.1.1.7) in the UK, 501Y.V2 (B.1.351) in South Africa, 501Y.V3 in Manaus, Brazil, and B.1.617/B.1.618 in India, which could lead to a severe epidemic rebound. Moreover, some variants have a stronger immune escape ability. To control the new SARS-CoV-2 variant, we may need to develop and redesign new vaccines repeatedly. So it is important to investigate how our immune system combats and responds to SARS-CoV-2 infection to develop safe and effective medical interventions. Objectives: In this study, we performed a longitudinal and proteome-wide analysis of antibodies in the COVID-19 patients to revealed some immune processes of COVID-19 patients against SARS-CoV-2 and found some dominant epitopes of a potential vaccine. Methods: Microarray assay, Antibody depletion assays, Neutralization assay. Results: We profiled a B-cell linear epitope landscape of SARS-CoV-2 and identified the epitopes specifically recognized by either IgM, IgG, or IgA. We found that epitopes more frequently recognized by IgM are enriched in non-structural proteins. We further identified epitopes with different immune responses in severe and mild patients. Moreover, we identified 12 dominant epitopes eliciting antibodies in most COVID-19 patients and identified five key amino acids of epitopes. Furthermore, we found epitope S-82 and S-15 are perfect immunogenic peptides and should be considered in vaccine design. Conclusion: This data provide useful information and rich resources for improving our understanding of viral infection and developing a novel vaccine/neutralizing antibodies for the treatment of SARS-CoV-2.

Serum Fibroblast Growth Factor 21 Level Is Associated with Aortic Stiffness in Patients on Maintenance Hemodialysis.

BACKGROUND: Fibroblast growth factor 21 (FGF-21) is a hormone that regulates glucose and lipid metabolism. High serum FGF-21 levels are associated with carotid atherosclerosis and coronary artery disease. This cross-sectional study aimed to assess the relationship between serum FGF-21 levels and carotid-femoral pulse wave velocity (cfPWV) in patients on maintenance hemodialysis (HD). METHODS: Blood samples and baseline characteristics were collected from 130 HD patients. Serum FGF-21 concentrations were measured with an enzyme-linked immunosorbent assay kit. Aortic stiffness was defined as a carotid-femoral pulse wave velocity (cfPWV) of more than 10 m/s. RESULTS: Of the 130 HD patients, aortic stiffness was diagnosed in 54 (41.5%). Serum FGF-21 levels were significantly higher in those with aortic stiffness than those without (P < 0.001). The FGF-21 level was independently associated with aortic stiffness (odds ratio (OR): 1.008; 95% CI: 1.003-1.012; P=0.001) after adjusting for diabetes mellitus, age, hypertension, C-reactive protein, and body weight in multivariable logistic regression analysis. Multivariable forward stepwise linear regression analysis also confirmed that the logarithmically transformed FGF-21 level (ß = 3.245, 95% CI: 1.593-4.987, P < 0.001) was an independent predictor of cfPWV values. The area under the receiver operating characteristic (ROC) curve predicting aortic stiffness by the serum FGF-21 level was 0.693 (95% CI: 0.606-0.771, P < 0.001). CONCLUSIONS: Serum FGF-21 level positively correlates with cfPWV and is also an independent predictor of aortic stiffness in maintenance HD patients.

Positive correlation of serum indoxyl sulfate level with peripheral arterial disease in hemodialysis patients.

OBJECTIVES: Indoxyl sulfate, known for its cardiovascular toxicity, is associated with vascular and coronary artery diseases and increased mortality. Peripheral arterial disease, defined by low ankle-brachial index, is associated with increased mortality in patients on hemodialysis. The present study aimed to determine the relationship between the serum indoxyl sulfate level and peripheral arterial disease in patients on maintenance hemodialysis. METHODS: The present cross-sectional, single-center study included 75 patients on maintenance hemodialysis. Serum indoxyl sulfate levels were determined by high-performance liquid chromatography-mass spectrometry. Ankle-brachial index values were measured using an automated oscillometric device. Patients with ankle-brachial indexes of < 0.9 were categorized into the low ankle-brachial index group. RESULTS: In the study cohort, 12 of the 75 patients (16.0%) had low ankle-brachial indexes. The rates of diabetes mellitus (p = 0.010) as well as the serum levels of C-reactive protein (p < 0.001) and indoxyl sulfate (p < 0.001) were higher in the low ankle-brachial index group than the normal ankle-brachial index group. The multivariable logistic regression analysis revealed that serum levels of indoxyl sulfate (odds ratio = 1.123, 95% confidence interval 1.011-1.249, p = 0.031) and C-reactive protein (each 0.1 mg/dL increase, odds ratio = 1.169, 95% confidence interval 1.018-1.343, p = 0.027) were independently associated with peripheral arterial disease in patients on maintenance hemodialysis. CONCLUSIONS: Serum indoxyl sulfate levels were associated with peripheral arterial disease in patients on maintenance hemodialysis.

Anti-PD1/PDL1 IgG subclass distribution in ten cancer types and anti-PD1 IgG4 as biomarker for the long time survival in NSCLC with anti-PD1 therapy.

BACKGROUND: Antibodies targeting programmed cell death-1(PD1) and its ligand (PDL1) have revolutionized cancer therapy. However, little is known about the preexisted anti-PD1/PDL1 autoantibodies (AAbs) distribution in multiple cancer types, nor is their potential biomarker role for anti-PD1 therapy. METHOD: Plasma anti-PD1/PDL1 AAb IgG and subclasses (IgG1-4) were detected by enzyme-linked immune sorbent assay (ELISA) in 190 cancer patients, covering 10 cancer types (lung, breast, esophageal, colorectal, liver, prostatic, cervical, ovarian, gastric cancers and lymphoma), the comprehensive correlation of AAbs with multiple clinical parameters was analyzed. We further tested these AAbs in 76 non-small cell lung cancer (NSCLC) samples receiving anti-PD1 therapy, the association of AAbs level with survival was analyzed and validated in an independent cohort (n = 32). RESULTS: Anti-PD1/PDL1 AAb IgG were globally detected in 10 types of cancer patients. IgG1 and IgG2 were the major subtypes for anti-PD1/PDL1 AAbs. Correlation analysis revealed a distinct landscape between various cancer types. The random forest model indicated that IgG4 subtype was mostly associated with cancer. In discovery cohort of 76 NSCLC patients, high anti-PD1 IgG4 was associated with a reduced overall survival (OS, p = 0.019), not progression-free survival (PFS, p = 0.088). The negative association of anti-PD1 IgG4 with OS was validated in 32 NSCLC patients (p = 0.032). CONCLUSION: This study reports for the first time the distribution of preexisted anti-PD1/PDL1 AAb IgG and subclasses across 10 cancer types. Moreover, the anti-PD1 AAb IgG4 subclass was identified to associate with OS, which may serve as a potential biomarker for anti-PD1 therapeutic survival benefit in NSCLC patients.

Novel neutralizing chicken IgY antibodies targeting 17 potent conserved peptides identified by SARS-CoV-2 proteome microarray, and future prospects.

Introduction: An approach toward novel neutralizing IgY polyclonal antibodies (N-IgY-pAb) against SARS-CoV-2 S-ECD was developed. Material and methods: The novel N-IgY-pAb and its intranasal spray response against the wild type ("'WH-Human 1") SARS-CoV-2 virus, variants of Delta or Omicron were up to 98%. Unique virus peptides binding to N-IgY-pAb were screened by a SARS-CoV-2 proteome microarray. Results: Seventeen mutation-free peptides with a Z-score > 3.0 were identified as potent targets from a total of 966 peptides. The new findings show that one is in the RBM domain (461LKPFERDISTEIYQA475 ), two are in the NTD domain (21RTQLPPAYTNSFTRG35, 291CALDPLSETKCTLKS305) four are in the C1/2-terminal (561PFQQFGRDIADTTDA575,571DTTDAVRDPQTLEIL585,581TLEILDITPCSFGGV595, 661ECDIPIGAGICASYQ675 ), three are in the S1/S2 border (741YICGDSTECSNLLLQ755, 811KPSKRSFIEDLLFNK825, 821LLFNKVTLADAGFIK835) one target is in HR2 (1161SPDVDLGDISGINAS1175) and one is in HR2-TM (1201QELGKYEQYIKWPWY1215). Moreover, five potential peptides were in the NSP domain: nsp3-55 (1361SNEKQEILGTVSWNL1375), nsp14-50 (614HHANEYRLYLDAYNM642, ORF10-3 (21MNSRNYIAQVDVVNFNLT38, ORF7a-1(1MKIILFLALITLATC15) and ORF7a-12 (1116TLCFTLKRKTE121). Discussion and conclusion: We concluded that the N-IgY-pAb could effectively neutralize the SARS-CoV-2. The new findings of seventeen potent conserved peptides are extremely important for developing new vaccines and "cocktails" of neutralizing Abs for efficient treatments for patients infected with SARS-CoV-2.

A new strategy for the fabrication of a flexible and highly sensitive capacitive pressure sensor.

The development of flexible capacitive pressure sensors has wide application prospects in the fields of electronic skin and intelligent wearable electronic devices, but it is still a great challenge to fabricate capacitive sensors with high sensitivity. Few reports have considered the use of interdigital electrode structures to improve the sensitivity of capacitive pressure sensors. In this work, a new strategy for the fabrication of a high-performance capacitive flexible pressure sensor based on MXene/polyvinylpyrrolidone (PVP) by an interdigital electrode is reported. By increasing the number of interdigital electrodes and selecting the appropriate dielectric layer, the sensitivity of the capacitive sensor can be improved. The capacitive sensor based on MXene/PVP here has a high sensitivity (~1.25 kPa-1), low detection limit (~0.6 Pa), wide sensing range (up to 294 kPa), fast response and recovery times (~30/15 ms) and mechanical stability of 10000 cycles. The presented sensor here can be used for various pressure detection applications, such as finger pressing, wrist pulse measuring, breathing, swallowing and speech recognition. This work provides a new method of using interdigital electrodes to fabricate a highly sensitive capacitive sensor with very promising application prospects in flexible sensors and wearable electronics.

A quasispecies in a BHK-21 cell-derived virulent Tembusu virus strain contains three groups of variants with distinct virulence phenotypes.

Previous studies resulted in the isolation of a low-virulence plaque-purified variant from the third passage (P3) in BHK-21 cells of a Tembusu virus (TMUV) isolate, suggesting the presence of viral quasispecies in the P3 culture. To confirm this notion, the fourth passage virus (P4) was prepared by infecting BHK-21 cells with P3 for isolation of more variants. We isolated 10 plaque-purified viruses. Comparative genome sequence analysis identified six of the 10 viruses as genetically different variants, which harbored a total of eight amino acid differences in the envelope, NS1, NS3, and NS5 proteins. When tested in a 2-day-old Pekin duck model, P4 caused 80 % mortality, belonging to a high-virulence TMUV strain. Out of the six genetically different variants, two presented high-virulence, one exhibited moderate-virulence, and three displayed low-virulence, causing 60 %-70 %, 40 %, and 10 % mortalities, respectively. These results demonstrate that P4 contains at least three groups of variants with distinct virulence phenotypes. Analysis of links between the eight residues and virulence of the six variants identified NS1 protein residue 183 and NS5 protein residues 275 and/or 287 as novel determinants of TMUV virulence. The analysis also provided a new clue for future studies on the molecular basis of TMUV virulence in terms of genetic interaction of different proteins. Overall, our study provides direct evidence to suggest that TMUV exists in in vitro culture of a virulent isolate as a quasispecies, which may enhance our understanding of molecular mechanism of TMUV virulence.

Dynamic landscape mapping of humoral immunity to SARS-CoV-2 identifies non-structural protein antibodies associated with the survival of critical COVID-19 patients.

A comprehensive analysis of the humoral immune response to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is essential in understanding COVID-19 pathogenesis and developing antibody-based diagnostics and therapy. In this work, we performed a longitudinal analysis of antibody responses to SARS-CoV-2 proteins in 104 serum samples from 49 critical COVID-19 patients using a peptide-based SARS-CoV-2 proteome microarray. Our data show that the binding epitopes of IgM and IgG antibodies differ across SARS-CoV-2 proteins and even within the same protein. Moreover, most IgM and IgG epitopes are located within nonstructural proteins (nsps), which are critical in inactivating the host's innate immune response and enabling SARS-CoV-2 replication, transcription, and polyprotein processing. IgM antibodies are associated with a good prognosis and target nsp3 and nsp5 proteases, whereas IgG antibodies are associated with high mortality and target structural proteins (Nucleocapsid, Spike, ORF3a). The epitopes targeted by antibodies in patients with a high mortality rate were further validated using an independent serum cohort (n = 56) and using global correlation mapping analysis with the clinical variables that are associated with COVID-19 severity. Our data provide fundamental insight into humoral immunity during SARS-CoV-2 infection. SARS-CoV-2 immunogenic epitopes identified in this work could also help direct antibody-based COVID-19 treatment and triage patients.