Exploring waste separation using an extended theory of planned behavior: a comparison between adults and children.

This study applied an extended model of the theory of planed behavior (TPB) to compare the differences in waste separation behavior between children (ages 9 to 12, N = 339) and adults (ages 18 to 66, N = 379). We examined the relations among waste separation attitude, subjective norm, perceived behavioral control, knowledge, awareness, intention, and behavior. The results showed waste separation knowledge of children was less than that of adults. Structure equation model results also revealed robust differences between children and adults. For adults, TPB variables (attitude, subjective norm, and perceived behavioral control) and knowledge are significantly positively related to their waste separation intention. Meanwhile, perceived behavioral control and intention are positively related to adults' behavior. However, for children, only perceived behavioral control and awareness are positively related to intention, and perceived behavioral control is positively related to behavior. Moreover, the predictive power of the extended TPB model on children's waste separation intention and behavior are lower than those of adults. The different results may be due to children's immature cognitive abilities. This study enhanced the understanding of the different waste separation behavior determinants between children and adults. The findings are useful for developing tailored policies and promoting children's waste separation behavior.

Highly efficient and selective removal of anionic dyes from aqueous solutions using polyacrylamide/peach gum polysaccharide/attapulgite composite hydrogels with positively charged hybrid network.

To avoid the weakness (lower adsorption rate and selectivity) of peach gum polysaccharide (PGP) and improve the adsorption performance of polyacrylamide (PAAm) hydrogel (lower adsorption capacity), in the present work, the PGP was chemically tailored to afford ammoniated PGP (APGP) and quaternized PGP (QPGP), and attapulgite (ATP) was bi-functionalized with cation groups and carbon­carbon double bond. Then, PAAm/APGP and PAAm/QPGP/ATP hydrogels were synthesized via redox polymerization. The synthesis procedure and properties of hydrogels were traced by FTIR, SEM, XPS, TGA, TEM, and BET methods, and the dye adsorption performance of the hydrogels was evaluated using the new coccine (NC) and tartrazine (TTZ) aqueous solutions as the model anionic dyes. Effects of initial dye concentration, pH, and ionic strength on the adsorption were investigated. Compared with PAAm/APGP hydrogel, PAAm/APGP/ATP hydrogel exhibits higher adsorption rate, superior adsorption capacity, stability, and selectivity towards anionic dye. The adsorption process of PAAm/QPGP/ATP hydrogel reached equilibrium in about 20 min and followed the pseudo-second-order kinetic model and Langmuir isotherm. The adsorption capacities towards NC and TTZ of PAAm/QPGP/ATP hydrogel were calculated as 873.235 and 731.432 mg/g. This hydrogel adsorbent originating from PAAm, PGP, and ATP shows great promise for application in practical water treatment.

High-Toughness CO2-Sourced Ionic Polyurea Adhesives.

Polyurea (PUa) adhesives are renowned for their exceptional adhesion to diverse substrates even in harsh environments. However, the presence of quadruple bidentate intermolecular hydrogen bonds in the polymer chains creates a trade-off between cohesive energy and interfacial adhesive energy. To overcome this challenge, a series of CO2-sourced ionic PUa adhesives with ultratough adhesion to various substrates are developed. The incorporated ionic segments within the adhesive serve to partially mitigate the intermolecular hydrogen bonding interactions while conferring unique electrostatic interactions, leading to both high cohesive energy and interfacial adhesive energy. The maximum adhesive strength of 10.9 MPa can be attained by ionizing the CO2-sourced PUa using bromopropane and subsequently exchanging the anion with lithium bis(trifluoromethylsulfonyl)imide. Additionally, these ionic PUa adhesives demonstrate several desirable properties such as low-temperature stability (-80 °C), resistance to organic solvents and water, high flame retardancy, antibacterial activity, and UV-fluorescence, thereby expanding their potential applications. This study presents a general and effective approach for designing high-strength adhesives suitable for a wide array of uses.

CCDC50 promotes tumor growth through regulation of lysosome homeostasis.

The maintenance of lysosome homeostasis is crucial for cell growth. Lysosome-dependent degradation and metabolism sustain tumor cell survival. Here, we demonstrate that CCDC50 serves as a lysophagy receptor, promoting tumor progression and invasion by controlling lysosomal integrity and renewal. CCDC50 monitors lysosomal damage, recognizes galectin-3 and K63-linked polyubiquitination on damaged lysosomes, and specifically targets them for autophagy-dependent degradation. CCDC50 deficiency causes the accumulation of ruptured lysosomes, impaired autophagic flux, and superfluous reactive oxygen species, consequently leading to cell death and tumor suppression. CCDC50 expression is associated with malignancy, progression to metastasis, and poor overall survival in human melanoma. Targeting CCDC50 suppresses tumor growth and lung metastasis, and enhances the effect of BRAFV600E inhibition. Thus, we demonstrate critical roles of CCDC50-mediated clearance of damaged lysosomes in supporting tumor growth, hereby identifying a potential therapeutic target of melanoma.

Association between resting myocardial work indices and stress myocardial perfusion in patients with angina and non-obstructive coronary artery disease.

Background: Myocardial work (MW) indices and longitudinal strain (LS) are sensitive markers of early left ventricular systolic dysfunction. Stress computed tomography myocardial perfusion imaging (CT-MPI) can assess early myocardial ischemia. The association between resting MW indices and stress myocardial perfusion remains unclear. This study compares resting MW indices with LS to assess stress myocardial perfusion in angina patients with non-obstructive coronary artery disease (CAD). Methods: Eighty-four patients who underwent resting echocardiography, coronary computed tomography angiography, and stress CT-MPI were reviewed. Seventeen myocardial segments were divided into three regions according to the epicardial coronary arteries. Global indices included global longitudinal strain (GLS), global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE). Regional indices included regional longitudinal strain (RLS), regional work index (RWI), and regional work efficiency (RWE). Reduced global perfusion was defined as an average stress myocardial blood flow (MBF) <116 mL/100 mL/min for the whole heart. Reduced regional perfusion was defined as an average stress MBF <116 mL/100 mL/min for the coronary territories. No patients demonstrated obstructions in the epicardial coronary arteries (stenosis diameter <50%). The MW indices and LS were compared. Receiver operating characteristic curves were constructed and logistic regression analyses were used to investigate the predictors of reduced myocardial perfusion. Results: Patients with reduced stress perfusion demonstrated reduced GLS, GWI, GCW, and GWE (P<0.05) and increased GWW (P<0.05). After adjustment for age and sex, GWE was still independently associated with reduced myocardial perfusion (odds ratio =0.386, 95% confidence interval: 0.214-0.697; P<0.05). Receiver operating characteristic curves reflected the good diagnostic ability of GWE and its superiority to GLS (area under the curve: 0.858 vs. 0.741). The optimal cutoff GWE value was 95% (sensitivity, 70%; specificity, 90%). Regions with lower stress perfusion showed lower RLS, RWI, and RWE (P<0.05). The optimal cutoff value of RWE for predicting reduced regional perfusion was 95%, with an area under the curve of 0.780, a sensitivity of 62%, and a specificity of 83%. Conclusions: Resting MW indices perform well in assessing global and regional stress myocardial perfusion in angina patients with non-obstructive CAD, and GWE is superior to GLS in the global evaluations.

PACT inhibits the replication of SARS-CoV-2 through the blockage of GSK-3ß-N-nsp3 cascade.

The protein activator of protein kinase R (PKR) (PACT) has been shown to play a crucial role in stimulating the host antiviral response through the activation of PKR, retinoic acid-inducible gene I, and melanoma differentiation-associated protein 5. Whether PACT can inhibit viral replication independent of known mechanisms is still unrevealed. In this study, we show that, like many viruses, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) hijacks GSK-3ß to facilitate its replication. GSK-3ß-induced phosphorylation on N protein increased the interaction between N protein and nsp3. Thus, GSK-3ß-N-nsp3 cascade promotes viral replication. Although SARS-CoV-2 can sabotage the activation of AKT, the upstream proteins suppressing the activation of GSK-3ß, we found that the host can use PACT, another protein kinase, instead of AKT to decrease the activity of GSK-3ß and the interaction between PACT and GSK-3ß is enhanced upon viral infection. Moreover, PACT inhibited the activity of GSK-3ß independent of its well-studied double-stranded RNA binding and PKR activating ability. In summary, this study identified an unknown function of PACT in inhibiting SARS-CoV-2 replication through the blockage of GSK-3ß-N-nsp3 cascade.

Spike substitution T813S increases Sarbecovirus fusogenicity by enhancing the usage of TMPRSS2.

SARS-CoV Spike (S) protein shares considerable homology with SARS-CoV-2 S, especially in the conserved S2 subunit (S2). S protein mediates coronavirus receptor binding and membrane fusion, and the latter activity can greatly influence coronavirus infection. We observed that SARS-CoV S is less effective in inducing membrane fusion compared with SARS-CoV-2 S. We identify that S813T mutation is sufficient in S2 interfering with the cleavage of SARS-CoV-2 S by TMPRSS2, reducing spike fusogenicity and pseudoparticle entry. Conversely, the mutation of T813S in SARS-CoV S increased fusion ability and viral replication. Our data suggested that residue 813 in the S was critical for the proteolytic activation, and the change from threonine to serine at 813 position might be an evolutionary feature adopted by SARS-2-related viruses. This finding deepened the understanding of Spike fusogenicity and could provide a new perspective for exploring Sarbecovirus' evolution.

Nucleon Energy Correlators for the Color Glass Condensate.

We demonstrate the recently proposed nucleon energy-energy correlator (NEEC) f_{EEC}(x,θ) can unveil the gluon saturation in the small-x regime in eA collisions. The novelty of this probe is that it is fully inclusive just like the deep-inelastic scattering (DIS), with no requirements of jets or hadrons but still provides an evident portal to the small-x dynamics through the shape of the θ distribution. We find that the saturation prediction is significantly different from the expectation of the collinear factorization.

Non-suicidal self-injury and professional psychological help-seeking among Chinese left-behind children: prevalence and influencing factors.

BACKGROUND: Non-suicidal self-injury (NSSI) is a risk factor for suicide. This study aimed to investigate the prevalence of NSSI and professional psychological help-seeking status and influencing factors among left-behind children (LBC) in China. METHODS: We implemented a population-based cross-sectional study in participants aged 10-18 years. Sociodemographic characteristics, NSSI, help-seeking status and coping style were measured by self-reported questionnaires. A total of 16,866 valid questionnaires were collected, including 6096 LBC. Binary logistic regression models were used to analyze the factors influencing NSSI and professional psychological help-seeking. RESULTS: The incidence of NSSI among LBC was 4.6%, significantly higher than that of non-left-behind children (NLBC). This incidence was higher among girls. Moreover, 53.9% of LBC with NSSI did not receive any treatment and only 22.0% sought professional psychological help. LBC often adopt emotion-oriented coping styles, specifically, those with NSSI. LBC with NSSI who seek professional help tend to adopt problem-oriented coping styles. Logistic regression analysis revealed that girls, learning stage, single-parent, remarried families, patience, and emotional venting were risk factors for NSSI in LBC, while problem-solving and social support seeking were protective factors. Moreover, problem-solving was also a predictor for seeking professional psychological help, patience will prevent it. LIMITATIONS: This was an online survey. CONCLUSIONS: The prevalence of NSSI in LBC is high. Gender, grade, family structure, and coping style affect the occurrence of NSSI among LBC. Only a few LBC with NSSI seek professional psychological help, while the coping style will affect the help-seeking behavior.

Unsupervised Learning-Guided Accelerated Discovery of Alkaline Anion Exchange Membranes for Fuel Cells.

Without insight into the correlation between the structure and properties, anion exchange membranes (AEMs) for fuel cells are developed usually using the empirical trial and error method or simulation methods. Here, a virtual module compound enumeration screening (V-MCES) approach, which does not require the establishment of expensive training databases and can search the chemical space containing more than 4.2×105 candidates was proposed. The accuracy of the V-MCES model was considerably improved when the model was combined with supervised learning for the feature selection of molecular descriptors. Techniques from V-MCES, correlating the molecular structures of the AEMs with the predicted chemical stability, generated a ranking list of potential high stability AEMs. Under the guidance of V-MCES, highly stable AEMs were synthesized. With understanding of AEM structure and performance by machine learning, AEM science may enter a new era of unprecedented levels of architectural design.

SARS-CoV-2 NSP7 inhibits type I and III IFN production by targeting the RIG-I/MDA5, TRIF, and STING signaling pathways.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a poor inducer of innate antiviral immunity, and the underlying mechanism still needs further investigation. Here, we reported that SARS-CoV-2 NSP7 inhibited the production of type I and III interferons (IFNs) by targeting the RIG-I/MDA5, Toll-like receptor (TLR3)-TRIF, and cGAS-STING signaling pathways. SARS-CoV-2 NSP7 suppressed the expression of IFNs and IFN-stimulated genes induced by poly (I:C) transfection and infection with Sendai virus or SARS-CoV-2 virus-like particles. NSP7 impaired type I and III IFN production activated by components of the cytosolic dsRNA-sensing pathway, including RIG-I, MDA5, and MAVS, but not TBK1, IKKε, and IRF3-5D, an active form of IRF3. In addition, NSP7 also suppressed TRIF- and STING-induced IFN responses. Mechanistically, NSP7 associated with RIG-I and MDA5 prevented the formation of the RIG-I/MDA5-MAVS signalosome and interacted with TRIF and STING to inhibit TRIF-TBK1 and STING-TBK1 complex formation, thus reducing the subsequent IRF3 phosphorylation and nuclear translocation that are essential for IFN induction. In addition, ectopic expression of NSP7 impeded innate immune activation and facilitated virus replication. Taken together, SARS-CoV-2 NSP7 dampens type I and III IFN responses via disruption of the signal transduction of the RIG-I/MDA5-MAVS, TLR3-TRIF, and cGAS-STING signaling pathways, thus providing novel insights into the interactions between SARS-CoV-2 and innate antiviral immunity.

Event-Triggered Distributed Average Tracking Control for Lipschitz-Type Nonlinear Multiagent Systems.

This article investigates the event-triggered distributed average tracking (ETDAT) control problems for the Lipschitz-type nonlinear multiagent systems with bounded time-varying reference signals. By using the state-dependent gain design approach and event-triggered mechanism, two types of ETDAT algorithms called: 1) static and 2) adaptive-gain ETDAT algorithms are developed. It is the first time to introduce the event-triggered strategy into DAT control algorithms and investigate the ETDAT problem for multiagent systems with Lipschitz nonlinearities, which is more practical in real physical systems and can better meet the needs of practical engineering applications. Besides, the adaptive-gain ETDAT algorithms do not need any global information of the network topology and are fully distributed. Finally, a simulation example of the Watts-Strogatz small-world network is presented to illustrate the effectiveness of the adaptive-gain ETDAT algorithms.

Low Pt loading for high-performance fuel cell electrodes enabled by hydrogen-bonding microporous polymer binders.

A key challenge for fuel cells based on phosphoric acid doped polybenzimidazole membranes is the high Pt loading, which is required due to the low electrode performance owing to the poor mass transport and severe Pt poisoning via acid absorption on the Pt surface. Herein, these issues are well addressed by design and synthesis of effective catalyst binders based on polymers of intrinsic microporosity (PIMs) with strong hydrogen-bonding functionalities which improve phosphoric acid binding energy, and thus preferably uphold phosphoric acid in the vicinity of Pt catalyst particles to mitigate the adsorption of phosphoric acid on the Pt surface. With combination of the highly mass transport microporosity, strong hydrogen-bonds and high phosphoric acid binding energy, the tetrazole functionalized PIM binder enables an H2-O2 cell to reach a high Pt-mass specific peak power density of 3.8 W mgPt-1 at 160 °C with a low Pt loading of only 0.15 mgPt cm-2.

A ROS/Akt/NF-κB Signaling Cascade Mediates Epidermal Growth Factor-Induced Epithelial-Mesenchymal Transition and Invasion in Human Breast Cancer Cells.

Background: As one of the most widely used anti-diabetic drugs for type II diabetes, metformin has been shown to exhibit anti-cancer activity in recent years. Epidermal growth factor (EGF) and its receptor, EGFR, play important roles in cancer metastasis in various tumors, including breast cancer. Epithelial-mesenchymal transition (EMT) is a critical process for cancer invasion and metastasis. In this study, we use EGF as a metastatic inducer to investigate the effect of metformin on cancer cell migration, invasion and EMT. Methods: Human breast cancer MCF-7 cells were exposed to EGF with or without metformin or N-acetyl cysteine (NAC). The effects of metformin on breast cancer cell proliferation were analyzed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. The production of reactive oxygen species (ROS) was tested using 2,7-dichlorodihydrofluorecein diacetate (DCFH-DA). The migratory and invasive abilities of tumor cells were analyzed using wound healing assay and transwell invasion assay, respectively. The expressions of E-cadherin, N-cadherin and Snail were tested using real-time quantitative polymerase chain reaction (qRT-PCR) and western blotting at mRNA and protein levels. The activation of protein kinase B (Akt) and nuclear factor kappa B (NF-κB) were measured by western blotting. Results: Our results showed that metformin inhibited breast cancer cell proliferation in a dose-dependent manner with or without EGF. EGF-induced alterations in cell morphology that are characteristic of EMT were reversed by metformin. Metformin also inhibited the EGF-modulated expression of E-cadherin, N-cadherin and Snail and further suppressed cell invasion and migration. In addition, metformin suppressed EGF-induced phosphorylation of Akt and NF-κB. ROS is involved in EGF-induced cancer invasion and activation of phosphatidylinositol 3-kinase (PI3K)/Akt/NF-κB pathway. Conclusion: Taken together, these data indicate that metformin suppresses EGF-induced breast cancer cell migration, invasion and EMT through the inhibition of the PI3K/Akt/NF-κB pathway. These results provide a novel mechanism to explain the role of metformin as a potent anti-metastatic agent in breast cancer cells.

Investigation of coenzyme Q10 status, serum amyloid-ß, and tau protein in patients with dementia.

Objectives: Dementia is an oxidative stress-related disease. Coenzyme Q10 is a nutrient that occurs naturally in the human body and acts as an antioxidant. The purpose of this study was to investigate the relationships of coenzyme Q10 status, biomarkers for dementia (amyloid ß and tau protein), and antioxidant capacity in patients with dementia. Methods: Eighty dementia patients aged ≥60 years and with a mini mental state examination (MMSE) score ≤ 26 were enrolled. The levels of coenzyme Q10, total antioxidant capacity (TAC), amyloid ß, and tau protein were measured. Results: A total of 73% of patients had a low coenzyme Q10 status. Patients with low coenzyme Q10 status had a significantly higher level of serum amyloid ß-42 and amyloid ß-42/40 ratio (p < 0.05). Coenzyme Q10 status was significantly correlated with the values of TAC, MMSE score, amyloid ß-42, and amyloid ß-42/40 ratio (p < 0.05) but not with tau protein. Additionally, a high proportion of moderate dementia patients were found to have low coenzyme Q10 status (p = 0.07). Conclusion: Patients with dementia suffered from coenzyme Q10 deficiency, and the degree of deficiency was related to the level of amyloid-ß and antioxidant capacity. Since adequate level of coenzyme Q10 may delay the progression of dementia, monitoring coenzyme Q10 status in patients with dementia is necessary.

[Effects of Interleukin-6 Gene Knockout on ß-amyloid Deposition and Cognition in 5×FAD Mouse Model of Alzheimer's Disease].

Objective To explore the effects of interleukin-6 (IL-6) gene knockout on the cognitive function and pathological changes in 5×FAD transgenic mice of Alzheimer's disease.Methods IL-6+/- mice were crossed with 5×FAD mice to establish the 5×FAD;IL-6-/- mouse model,and 3-month-old and 10-month-old mice were selected for experiments.The cognitive function of mice was detected by behavioral tests,and HE staining and ß-amyloid (Aß) immunohistochemical staining were performed to detect the pathological changes of mouse brain tissue.Results The number of 5×FAD;IL-6-/- model mice (3 months old,n=20;10 months old,n=5) and 5×FAD littermate control (3 months old,n=26;10 months old,n=24) conformed to the Mendel's law.Compared with that of the 5×FAD mice at the same age,the discrimination ratio of 3-month-old 5×FAD;IL-6-/- mice increased in the novel object recognition test (q=3.890,P=0.002).Morris water maze test results showed that the 3-month-old 5×FAD;IL-6-/- mice had longer time spent in target quadrant (q=3.797,P=0.012) and more times of crossing platform (q=2.505,P=0.017) than the 5×FAD mice at the same age.The results of immunohistochemical staining showed that IL-6 knockout reduced the Aß deposition in the hippocampus (q=13.490,P=0.002;q=45.680,P<0.001) and cortex (q=16.830,P=0.001;q=14.180,P=0.001) of 5×FAD mice.Conclusion IL-6 gene knockout can significantly improve the spatial memory and reduce the Aß deposition in the brain of 5×FAD mice.

Genome-Wide Analysis of the Indispensable Role of Non-structural Proteins in the Replication of SARS-CoV-2.

Understanding the process of replication and transcription of SARS-CoV-2 is essential for antiviral strategy development. The replicase polyprotein is indispensable for viral replication. However, whether all nsps derived from the replicase polyprotein of SARS-CoV-2 are indispensable is not fully understood. In this study, we utilized the SARS-CoV-2 replicon as the system to investigate the role of each nsp in viral replication. We found that except for nsp16, all the nsp deletions drastically impair the replication of the replicon, and nsp14 could recover the replication deficiency caused by its deletion in the viral replicon. Due to the unsuccessful expressions of nsp1, nsp3, and nsp16, we could not draw a conclusion about their in trans-rescue functions. Our study provided a new angle to understand the role of each nsp in viral replication and transcription, helping the evaluation of nsps as the target for antiviral drug development.

Inhibition of ALG3 stimulates cancer cell immunogenic ferroptosis to potentiate immunotherapy.

Immune checkpoint blockade therapy has drastically improved the prognosis of certain advanced-stage cancers. However, low response rates and immune-related adverse events remain important limitations. Here, we report that inhibiting ALG3, an a-1,3-mannosyltransferase involved in protein glycosylation in the endoplasmic reticulum (ER), can boost the response of tumors to immune checkpoint blockade therapy. Deleting N-linked glycosylation gene ALG3 in mouse cancer cells substantially attenuates their growth in mice in a manner depending on cytotoxic T cells. Furthermore, ALG3 inhibition or N-linked glycosylation inhibitor tunicamycin treatment synergizes with anti-PD1 therapy in suppressing tumor growth in mouse models of cancer. Mechanistically, we found that inhibiting ALG3 induced deficiencies of post-translational N-linked glycosylation modification and led to excessive lipid accumulation through sterol-regulated element-binding protein (SREBP1)-dependent lipogenesis in cancer cells. N-linked glycosylation deficiency-mediated lipid hyperperoxidation induced immunogenic ferroptosis of cancer cells and promoted a pro-inflammatory microenvironment, which boosted anti-tumor immune responses. In human subjects with cancer, elevated levels of ALG3 expression in tumor tissues are associated with poor patient survival. Taken together, we reveal an unappreciated role of ALG3 in regulating tumor immunogenicity and propose a potential therapeutic strategy for enhancing cancer immunotherapy.

ORF8 protein of SARS-CoV-2 reduces male fertility in mice.

As one of the most rapidly evolving proteins of the genus Betacoronavirus, open reading frames (ORF8's) function and potential pathological consequence in vivo are still obscure. In this study, we show that the secretion of ORF8 is dependent on its N-terminal signal peptide sequence and can be inhibited by reactive oxygen species scavenger and endoplasmic reticulum-Golgi transportation inhibitor in cultured cells. To trace the effect of its possible in vivo secretion, we examined the plasma samples of coronavirus disease 2019 (COVID-19) convalescent patients and found that the patients aged from 40 to 60 had higher antibody titers than those under 40. To explore ORF8's in vivo function, we administered the mice with ORF8 via tail-vein injection to simulate the circulating ORF8 in the patient. Although no apparent difference in body weight, food intake, and vitality was detected between vehicle- and ORF8-treated mice, the latter displayed morphological abnormalities of testes and epididymides, as indicated by the loss of the central ductal lumen accompanied by a decreased fertility in 5-week-old male mice. Furthermore, the analysis of gene expression in the testes between vehicle- and ORF8-treated mice identified a decreased expression of Col1a1, the loss of which is known to be associated with mice's infertility. Although whether our observation in mice could be translated to humans remains unclear, our study provides a potential mouse model that can be used to investigate the impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection on the human reproductive system.

Reverse genetics systems for SARS-CoV-2.

The ongoing pandemic of coronavirus disease 2019 (COVID-19) has caused severe public health crises and heavy economic losses. Limited knowledge about this deadly virus impairs our capacity to set up a toolkit against it. Thus, more studies on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) biology are urgently needed. Reverse genetics systems, including viral infectious clones and replicons, are powerful platforms for viral research projects, spanning many aspects such as the rescues of wild-type or mutant viral particles, the investigation of viral replication mechanism, the characterization of viral protein functions, and the studies on viral pathogenesis and antiviral drug development. The operations on viral infectious clones are strictly limited in the Biosafety Level 3 (BSL3) facilities, which are insufficient, especially during the pandemic. In contrast, the operation on the noninfectious replicon can be performed in Biosafety Level 2 (BSL2) facilities, which are widely available. After the outbreak of COVID-19, many reverse genetics systems for SARS-CoV-2, including infectious clones and replicons are developed and given plenty of options for researchers to pick up according to the requirement of their research works. In this review, we summarize the available reverse genetics systems for SARS-CoV-2, by highlighting the features of these systems, and provide a quick guide for researchers, especially those without ample experience in operating viral reverse genetics systems.