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1.
Zool Res ; 43(1): 40-51, 2022 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-34821085

RESUMO

Mountain systems harbor an evolutionarily unique and exceptionally rich biodiversity, especially for amphibians. However, the associated elevational gradients and underlying mechanisms of amphibian diversity in most mountain systems remain poorly understood. Here, we explored amphibian phylogenetic and functional diversity along a 2 600 m elevational gradient on Mount Emei on the eastern margin of the Qinghai-Tibetan Plateau in southwestern China. We also assessed the relative importance of spatial (area) and environmental factors (temperature, precipitation, solar radiation, normalized difference vegetation index, and potential evapotranspiration) in shaping amphibian distribution and community structure. Results showed that the phylogenetic and functional diversities were unimodal with elevation, while the standardized effect size of phylogenetic and functional diversity increased linearly with elevation. Phylogenetic net relatedness, nearest taxon index, and functional net relatedness index all showed a positive to negative trend with elevation, indicating a shift from clustering to overdispersion and suggesting a potential change in key processes from environmental filtering to competitive exclusion. Overall, our results illustrate the importance of deterministic processes in structuring amphibian communities in subtropical mountains, with the dominant role potentially switching with elevation. This study provides insights into the underlying assembly mechanisms of mountain amphibians, integrating multidimensional diversity.

2.
Food Chem ; 369: 130978, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34500209

RESUMO

In this paper, the effects of soybean protein isolate (SPI) on the formations of five heterocyclic aromatic amines (HAAs) in roasted pork were investigated. The levels of all five HAAs improved upon addition of 2.5% of SPI (P < 0.05). With higher SPI dosage, the levels of HAA decreased after seeing an increase. Two HAAs (MeIQx and 4,8-DiMeIQx) were inhibited by 10.0% of SPI, with the inhibitory efficiencies of 7.0 % and 85.7%, respectively. After being heated, the levels of both the free amino acids and carbonyl groups in the SPI were observed significantly increased, from 55.04 µg g·SPI-1 to 91.66 µg g·SPI-1 and from 123.85 ± 13.07 to 931.78 ± 32.56, respectively (P < 0.05). Therefore, the possible promotion mechanism of the SPI was speculated that the heated SPI would provide both the HAA precursors and carbonyls, which significantly promoted the Strecker degradation and generated more HAA intermediates (P < 0.05).


Assuntos
Compostos Heterocíclicos , Carne de Porco , Carne Vermelha , Aminas/análise , Animais , Culinária , Compostos Heterocíclicos/análise , Carne/análise , Carne Vermelha/análise , Soja , Suínos
3.
J Cell Physiol ; 2021 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-34812495

RESUMO

Dunaliella salina can accumulate a large amount of ß-carotene which is generally considered to be its terminal product of carotenoid metabolism. In this study, it was proved that D. salina has the ketolase (DsBKT) of catalyzing the synthesis of astaxanthin, the downstream products of ß-carotene. Therefore, the reason why D. salina does not synthesize astaxanthin is the purpose of this study. The enzymatic activity of DsBKT was detected by functional complementation assays in Escherichia coli, results showed that DsBKT had efficient ketolase activity toward ß-carotene and zeaxanthin to produce astaxanthin, indicating that there were complete astaxanthin-producing genes in Dunaliella. Unlike the induced expression of Lycopene cyclase (catalyzing ß-carotene synthesis) under salt stress, the expression of DsBKT was very low under both normal and stress conditions, which may be the main reason why D. salina cannot accumulate astaxanthin. On the contrary, with the astaxanthin-rich Haematococcus pluvialis as a control, its BKT gene was significantly upregulated under salt stress. Further study showed that DsBKT promoter had strong promoter ability and could stably drive the expression of ble-egfp in D. salina. Obviously, DsBKT promoter is not the reason of DsBKT not being expressed which may be caused by Noncoding RNA.

4.
Artigo em Inglês | MEDLINE | ID: mdl-34793675

RESUMO

MXene aerogels with a porous microstructure are a promising electromagnetic interference (EMI) shielding material due to its low density and excellent electrical conductivity, which has attracted widespread attention. Compared with traditional EMI shielding materials that rely on reflection as the primary mechanism, MXene aerogels with absorption as the dominant mechanism have greater potential for development as a novel EMI shielding material because of its ability to reduce environmental contamination from reflected electromagnetic (EM) waves from materials. In this study, a novel Ti3C2Tx MXene/PEDOT:PSS hybrid aerogel was presented by freeze-drying and thermal annealing using few-layered Ti3C2Tx MXene and the conductive polymer poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS). PEDOT:PSS not only improved the gelling ability of Ti3C2Tx but also successfully established a conductive bridge between MXene nanosheets. The experimental results demonstrated that the hybrid aerogel exhibited an obvious porous microstructure, which was beneficial for the multiple scattering of EM waves within the materials. The EMI shielding effectiveness and specific shielding effectiveness reached up to 59 dB and 10,841 dB·cm2·g-1, respectively, while the SER/SET ratio value was only 0.05, indicating superior wave absorption performance. Furthermore, the good impedance matching, due to the electrical conductance loss and polarization loss effect of the composites, plays a critical role in their excellent wave absorption and EMI shielding performance. Therefore, this work provides a practical approach for designing and fabricating lightweight absorption-dominated EMI shielding materials.

6.
World J Clin Cases ; 9(28): 8482-8491, 2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34754857

RESUMO

BACKGROUND: Diagnosing hyperandrogenemia in postmenopausal women is very difficult. It occasionally manifests as excessive hair growth or with no clinical manifestations, and is therefore often misdiagnosed or missed altogether. Ovarian steroid cell tumors that cause hyperandrogenemia in women account for approximately 0.1% of all ovarian tumors. Due to the low incidence, corresponding imaging reports are rare, so ovarian steroid cell tumors lacks typical imaging findings to differentiate it from other ovarian tumors. Therefore, we summarized its clinical and imaging characteristics through this case series, and elaborated on the differential diagnosis of steroid cell tumors. CASE SUMMARY: We report three cases of postmenopausal women with hyperandrogenemia. Only 1 patient showed virilization symptoms, the other two patients were completely asymptomatic. All patients underwent total hysterectomy + bilateral adnexectomy. Histological results showed one case of Leydig cell tumor and two cases of benign, non-specific steroid cell tumor. After the operation, the androgen levels of all patients returned to normal, and there was no clinical recurrence since follow-up. CONCLUSION: Although virilization caused by increased serum testosterone levels is an important clinical feature of ovarian steroid cell tumors, it is often asymptomatic. A solid, slightly hypoechoic, round or oval mass with uniform internal echo, richer blood flow in the solid part, and low resistance index are typical imaging features of ovarian steroid cell tumors. Diagnosis of ovarian steroid cell tumors after menopause is challenging, but surgery can be used for both diagnosis and clear treatment.

7.
J Pharm Anal ; 11(5): 628-637, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34765276

RESUMO

Berberine (BBR) is an isoquinoline alkaloid extracted from Coptis chinensis that improves diabetes, hyperlipidemia and inflammation. Due to the low oral bioavailability of BBR, its mechanism of action is closely related to the gut microbiota. This study focused on the CYP51 enzyme of intestinal bacteria to elucidate a new mechanism of BBR transformation by demethylation in the gut microbiota through multiple analytical techniques. First, the docking of BBR and CYP51 was performed; then, the pharmacokinetics of BBR was determined in ICR mice in vivo, and the metabolism of BBR in the liver, kidney, gut microbiota and single bacterial strains was examined in vitro. Moreover, 16S rRNA analysis of ICR mouse feces indicated the relationship between BBR and the gut microbiota. Finally, recombinant E. coli containing cyp51 gene was constructed and the CYP51 enzyme lysate was induced to express. The metabolic characteristics of BBR were analyzed in the CYP51 enzyme lysate system. The results showed that CYP51 in the gut microbiota could bind stably with BBR, and the addition of voriconazole (a specific inhibitor of CYP51) slowed down the metabolism of BBR, which prevented the production of the demethylated metabolites thalifendine and berberrubine. This study demonstrated that CYP51 promoted the demethylation of BBR and enhanced its intestinal absorption, providing a new method for studying the metabolic transformation mechanism of isoquinoline alkaloids in vivo.

8.
Opt Express ; 29(24): 40606-40616, 2021 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-34809396

RESUMO

We proposed an one-dimensional layer-stacked photonic crystal using anisotropic materials to realize ideal type-II Weyl points. The topological transition from Dirac to Weyl points can be clearly observed by tuning the twist angle between layers. Also, on the interface between the photonic type-II Weyl material and air, gapless surface states have been demonstrated in an incomplete bulk bandgap. By breaking parameter symmetry, these ideal type-II Weyl points would transform into the non-ideal ones, exhibiting topological surface states with single group velocity. Our work may provide a new idea for the realization of photonic semimetal phases by utilizing naturally anisotropic materials.

9.
Indian J Ophthalmol ; 69(12): 3579-3583, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34826999

RESUMO

Purpose: To evaluate the peripapillary changes after vitrectomy and silicone oil (SO) tamponade in eyes with rhegmatogenous retinal detachment (RRD). Methods: In this study, 25-gauge vitrectomy with SO tamponade was performed in 22 eyes with RRD. The radial peripapillary capillary (RPC) vessel density (VD) and retinal nerve fiber layer thickness (RNFLT) were assessed by optical coherence tomography angiography at 2, 4, 8, and 12 weeks postoperatively. The values of healthy fellow eyes were used as controls. Results: The global RPC VDs were significantly lower in the eyes with RRD than in fellow healthy eyes at 2 weeks (P < 0.001), and increased at 4 weeks, then decreased over time after surgery (F = 1.046, P = 0.377). The RPC VDs in the superior-hemifield were lower than those in the inferior-hemifield at 12 weeks postoperatively (t = -2.844, P = 0.010). The global RNFLTs decreased gradually after vitrectomy in the eyes with RRD (F = 1.312, P = 0.276). The RNFLTs in the superior-hemifield were thinner than those in the inferior-hemifield at 12 weeks postoperatively (t = -2.222, P = 0.037). The global, superior, and inferior RNFLTs were correlated with corresponding RPC VDs in the eyes with RRD at all time-points postoperatively (P < 0.05). Conclusion: RRD resulted in the decrease of RPC VDs. The RPC VDs recovered in the early postoperative period but were still lower than the normal level. Long-term application of SO tamponade resulted in the reduction of peripapillary VDs secondary to loss of RNFLTs.

10.
J Healthc Eng ; 2021: 6086106, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34795883

RESUMO

The application value of image mosaic algorithm (IMA) based CT imaging technology in the analysis of pathological characteristics of gastric polyp (GP) patients was explored in this work. 588 cases of GP patients in the hospital were selected as the research objects, and CT images based on IMA were adopted for examination. The patient's basic information, image performance, and gastroscopy results were recorded. The results showed that the absolute mean bright error (AMBE) index and information entropy of the IMA are 0.0625 and 7.0385, respectively. The clinical symptoms of patients were mostly abdominal pain (21.4%), abdominal distension (15.6%), and sour regurgitation (17.8%). The common size of GP was no more than 0.5 cm, and the common type was Yamada type II. There were notable differences between single and multiple GPs of different pathological types (P < 0.05). Proliferative polyps were mostly found in the stomach and antrum, while fundus gland polyps were mostly in the stomach and fundus. There was significant difference between the growth location of the hyperplastic polyp and basal gland polyp (P < 0.05). In summary, the CT images of IMA proposed in this paper can not only realize image splicing effectively but also were superior to the traditional SIFT method in the quality of splicing image and were conducive to the analysis of the pathological characteristics of GP patients, which had significant clinical promotion value.

11.
Langmuir ; 2021 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-34793678

RESUMO

A theoretical model was established to predict the morphology evolution of a volatile liquid lens evaporation on another immiscible liquid substrate surface. The theoretical model considered the dynamic process of contact line motion. On the basis of the boundary conditions established at the contact line, the morphology change of the liquid lens was calculated by numerically solving the Young-Laplace differential equations for the three interfaces. The mass evaporation rate was calculated by the diffusion-controlled evaporation model. Then, an experimental system was established to record the process of a hexane lens evaporation on the surface of an ionic liquid with a depth of 4 mm. The calculated hexane lens radius variation matches well with the experimental measurements, which shows the rationality of the present model. The calculated results show that the evaporation pattern of the liquid lens follows the constant contact-angle evaporation mode for ∼70% of the lifetime. During the later stage of evaporation, the contact angle decreases, accompanied by contraction of the contact line, which is similar to the mixed evaporation mode in the later stage of sessile droplet evaporation on a solid substrate surface. Furthermore, the influences of the initial hexane lens volume and the ionic liquid temperature on the dynamic contact angle were theoretically summarized. This study helps to provide in-depth insights into regulating the lens evaporation process on another immiscible liquid substrate surface to control the particle deposition mode.

12.
ACS Nano ; 2021 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-34797065

RESUMO

Molecular chirality recognition plays a pivotal role in chiral generation and transfer in living systems and makes important contribution to the development of diverse applications spanning from chiral separation to soft nanorobots. To detect chirality recognition, most of the molecular sensors described to date are based on the design and preparation of the host-guest complexation with chromophore or fluorophore at the reporter unit. Nevertheless, the involved tedious procedures and complicated chemical syntheses hamper their practical applications. Here, we report the plasmonically chiroptical detection of molecular chirality recognition without the need for a chromophore or fluorophore unit. This facile methodology is based on plasmonic nanotransducers that can convert molecular chirality recognitions occurring at nanoscale interfaces into asymmetrically amplified plasmonic circular dichroism readouts, enabling enantiospecific recognition and quantitative determination of the enantiomeric excess of small amino acids. Importantly, such a plasmon-based chirality sensing shows 102-103 amplification in the plasmonic circular dichroism signals from the detections of racemate and near-racemate of molecular analysts, demonstrating an extraordinary sensitivity to the host-guest enantioselective interactions. Furthermore, with advantages of easy-processing, cost-effective, and specific to interfacial molecular chirality, our chiroptical sensing scheme could hold considerable promise toward applications of enantioselective high-throughput screening in biology, stereochemistry, and pharmaceutics.

13.
Microb Pathog ; 161(Pt A): 105233, 2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34626767

RESUMO

BACKGROUND: Numerous studies have indicated that miRNAs might play significant roles in the development of hepatitis B virus (HBV) infection. while the miRNAs in occult HBV infection (OBI) are still largely unknown. METHODS: Initially, 15 HBV infection-related miRNAs in plasma of 10 OBI and 10 healthy controls (HCs) was analyzed by qRT-PCR. Significantly dysregulated miRNAs were subsequently validated in another 64 OBI, 20HCs, 31 chronic hepatitis B (CHB) and 20 asymptomatic HBsAg carriers (ASC). Furthermore, the potential biological functions and molecular mechanisms of miR-451a in HBV infection were investigated using HBV-expressing hepatoma cell lines. RESULTS: Compared to HCs, plasma miR-451a and miR-340-3p were significantly up-regulated in OBI, ASC and CHB patients, while no significant difference was found among OBI, ASC and CHB patients. ROC curve analysis indicated that both plasma miR-451a and miR-340-3p could moderately distinguish OBI from HCs, with AUCs of 0.76 and 0.78, respectively. When combined, the differentiation efficiency of this miRNA panel was better, with an AUC of 0.82. While, they both could not specifically separate the stage of chronic HBV infection. Functional experiments showed that overexpression of miR-451a might suppress HBV replication and gene expression in hepatoma cell lines. Mechanistically, miR-451a might inhibit HBV replication and gene expression by directly targeting ATF2. CONCLUSIONS: A plasma panel, including miR-340-3p and miR-451a that might suppress HBV replication by targeting ATF2, has the potential as biomarkers for HBV infection. In the setting of blood donations, this panel would be more practical to moderately differentiate OBI in HBsAg-negative donors.

14.
Phys Rev Lett ; 127(14): 144502, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34652207

RESUMO

Despite a long history of studies, acoustic waves are generally regarded as spinless scalar waves, until recent research revealed their rich structures. Here, we report the experimental observation of skyrmion configurations in acoustic waves. We find that surface acoustic waves trapped by a designed hexagonal acoustic metasurface give rise to skyrmion lattice patterns in the dynamic acoustic velocity fields (i.e., the oscillating acoustic air flows). Using an acoustic velocity sensing technique, we directly visualize a Néel-type skyrmion configuration of the acoustic velocity fields. We further demonstrate, respectively, the controllability and robustness of the acoustic skyrmion lattices by tuning the phase differences between the acoustic sources and by introducing local perturbations in our setup. Our study unveils a fundamental acoustic phenomenon that may enable unprecedented manipulation of acoustic waves and may inspire future technologies including advanced acoustic tweezers for the control of small particles.

15.
Enzyme Microb Technol ; 151: 109913, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34649686

RESUMO

Dunaliella bardawil, a unicellular green alga, can accumulate a large amount of lutein and ß-carotene under stresses. Using chemical inducers combined with abiotic stress to promote the accumulation of high value-added products such as lipids and carotenoids in microalgae has attracted more and more attention. In this study, creatinine was added into autotrophic medium to investigate its effects on the growth, chlorophyll content, and the ingredients and content of carotenoids in D. bardawil. The results showed that creatinine alone could significantly increase the biomass, chlorophyll and carotenoid contents of D. bardawil, among which the contents of lutein and ß-carotene were further increased, while the content of zeaxanthin was decreased. In order to further improve the content of the two carotenoids, different light intensities combined with creatinine have been adopted. Under 6.589 W/m2 light intensity, creatinine could effectively increase the production of lutein, zeaxanthin, α-carotene and ß-carotene. Compared with the control, the content of lutein increased by 46 % and the content of ß-carotene increased by 77 % when the concentration of creatinine was 500 µg/mL. In conclusion, creatinine can effectively improve the production lutein and ß-carotene in D. bardawil, which is more conducive under lower light intensity.


Assuntos
Clorofíceas , beta Caroteno , Carotenoides , Creatinina , Luteína
16.
Int J Gen Med ; 14: 6875-6883, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34703292

RESUMO

Background: This study proposes the investigation of electrical impedance tomography (EIT) as a useful predictor for ventilator weaning. Methods: The study design was a nested case-control study and patients who were admitted to the intensive care unit and underwent their first tracheal intubation were enrolled. Those who successfully completed ventilator weaning and extubation after the first spontaneous breathing trial (SBT) were included in the weaning success group, while those who did not pass the SBT or received secondary intubation within 48 hours were included in the weaning failure group. In both groups, EIT was adopted to record the monitoring data in three phases: before the SBT (pre-SBT), during the SBT (SBT), and after the SBT (post-SBT). Results: A total of 53 patients were enrolled, including 41 cases in the weaning success group and 12 cases in the weaning failure group. The logistic regression analysis showed that the pre-SBT global impedance (GI) and the SBT region of interest 2 (ROI2) were significantly higher in the weaning success group than in the weaning failure group (p = 0.0001 and p = 0.002). The pre-SBT GI predicted weaning success with a sensitivity of 0.524, a specificity of 0.818, a p-value of 0.0496, and a 95% confidence interval (CI) of 0.001-0.978. The sensitivity, specificity, p-value, and 95% CI for the SBT ROI2 were 1, 0.595, 0.0164, and 1.010-1.108, respectively. Conclusion: For patients without contraindications to EIT, the application of EIT is recommended to be added to the existing evaluation system for ventilator weaning, as it could help improve the weaning success rate. Further cohort studies are needed to investigate the actual efficacy of EIT after it has been added to the evaluation system.

17.
Pain Physician ; 24(7): E1085-E1097, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34704718

RESUMO

BACKGROUND: Thoracolumbar interfascial plane (TLIP) block as a novel plane block technique was proposed in 2015 and can be performed in patients undergoing lumbar spine surgery. However, no meta-analysis demonstrates the effects of TLIP block on postoperative pain undergoing lumbar spine surgery. OBJECTIVES: The purpose of this study is to evaluate the postoperative analgesic efficacy of TLIP block with patient-controlled analgesia (PCA) undergoing lumbar spine surgery compared to be given PCA alone after lumbar spine surgery. STUDY DESIGN: This meta-analysis pooled all data published in randomized controlled trials (RCTs) examining the efficacy of TLIP following lumbar spine surgery. METHODS: We conducted a comprehensive search of PubMed, Web of Science, Embase databases, the Cochrane Library, and Google Scholar for randomized controlled trials (RCTs) up to December 2020. According to the inclusion and exclusion criteria established in advance, "TLIP" and "lumbar spine surgery" related MeSH terms and free-text words were used. All of the data on visual analog scales (VAS) scores, PCA compression frequency, PCA consumption, and nausea rates were reported. All analyses were performed with RevMan 5.4 software. RESULTS: A total of 9 RCTs with 618 patients meet the inclusion criteria. The results demonstrated that VAS scores for pain during movement and while at rest were markedly lower in the TLIP group than those in the control group in all the postoperative periods (1-2 h, 12 h, 18 h, and 24 h) (P < 0.05). VAS scores at rest 1-2 h postoperatively (MD: -2.16; 95% CI: [-3.86, -0.46]); 12 h (MD: -1.22; 95% CI: [-2.33, -0.11]); 18 h (MD: -1.40; 95% CI: [-1.55, -1.24]); 24 h (MD: -1.38; 95% CI: [-1.94, -0.81]); VAS scores at movement 1-2 postoperatively (MD: -2.26; 95% CI: [-4.28, -0.23]); 12 h (MD: -2.11; 95% CI: [-3.13, -1.10]); 18 h (MD: -1.63; 95% CI: [-1.77, -1.48]); 24 h (MD: -1.47; 95% CI: [-1.98, -0.95]). Meanwhile, PCA compression frequency, PCA consumption, and nausea rates were significantly lower in the TLIP group after lumbar spine surgery (P < 0.05): PCA compressions frequency (MD: -4.08; 95% CI: [-5.28, -2.88]); PCA consumption (MD: -14.30; 95% CI: [-20.68, -7.92]); nausea rates (RR: 0.47; 95% CI: [0.32, 0.68]). LIMITATIONS: Despite 9 RCTs, the sample size was still small, so more high-quality RCTs with large samples will be urgently required for stronger evidence to support TLIP block in lumbar spine surgery. CONCLUSIONS: The TLIP block is an effective strategy to improve postoperative pain at rest/movement and to reduce PCA consumption in patients undergoing lumbar spine surgery, which exerts significant analgesia. In the future, it is worth being applied in lumbar spine surgery extensively.

18.
Nanomaterials (Basel) ; 11(10)2021 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-34684948

RESUMO

In this article, we demonstrate a facile, rapid, and practical approach to growing high-quality Cu2S nanosheets decorated with Ag nanoparticles (NPs) through the galvanic reduction method. The Ag/Cu2S nanosheets were efficiently applied to the surface-enhanced Raman scattering (SERS) and photocatalytic degradation applications. The photodegradation of RhB dye with the Ag/Cu2S nanosheets composites occurred at a rate of 2.9 times faster than that observed with the undecorated Cu2S nanosheets. Furthermore, the Ag/Cu2S nanosheets displayed highly sensitive SERS detection of organic pollutant (R6G) as low as 10-9 M. The reproducibility experiments indicated that the Ag/Cu2S nanosheets composites could be used for dual functionality in a new generation of outstandingly sensitive SERS probes for detection and stable photocatalysts.

20.
Viruses ; 13(10)2021 09 26.
Artigo em Inglês | MEDLINE | ID: mdl-34696367

RESUMO

The novel coronavirus pneumonia (COVID-19) pandemic is a great threat to human society and now is still spreading. Although several vaccines have been authorized for emergency use, only one recombinant subunit vaccine has been permitted for widespread use. More subunit vaccines for COVID-19 should be developed in the future. The receptor binding domain (RBD), located at the S protein of SARS-CoV-2, contains most of the neutralizing epitopes. However, the immunogenicity of RBD monomers is not strong enough. In this study, we fused the RBD-monomer with a modified Fc fragment of human IgG1 to form an RBD-Fc fusion protein. The recombinant vaccine candidate based on the RBD-Fc protein could induce high levels of IgG and neutralizing antibody in mice, and these could last for at least three months. The secretion of IFN-γ, IL-2 and IL-10 in the RBD-stimulated splenocytes of immunized mice also increased significantly. Our results first showed that the RBD-Fc vaccine could induce both humoral and cellular immune responses and might be an optional strategy to control COVID-19.

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