The ecdysis triggering hormone system is essential for reproductive success in Mythimna separata (Walker).

Ecdysis triggering hormone (ETH) was originally discovered as a key hormone that regulates insect moulting via binding to its receptor, ETH receptor (ETHR). However, the precise role of ETH in moth reproduction remains to be explored in detail. ETH function was verified in vivo using Mythimna separata (Walker), an important cereal crop pest. RT-qPCR analysis revealed that transcriptional expression profiles of MsepETH showed evident sexual dimorphism in the adult stage. MsepETH expression increased in the females on day 3 and persisted thereafter till day 7, consistent with female ovarian maturation, and was merely detectable in males. Meanwhile, MsepETH expression levels were significantly higher in the trachea than in other tissues. MsepETHR-A and MsepETHR-B were expressed in both sexes and were significantly higher in the antennae than in other tissues. MsepETH and MsepETHR knockdown in females by RNA interference significantly reduced the expression of MsepETH, MsepETHR-A, MsepETHR-B, MsepJHAMT, and MsepVG, which delayed egg-laying and significantly reduced egg production. RNAi 20-hydroxyecdysone (20E) receptor (EcR) decreased MsepETH expression whereas injecting 20E restored egg production that had been disrupted by MsepETH interference. Meanwhile, RNAi juvenile hormone (JH) methoprene tolerant protein (Met) also decreased MsepETH expression and smearing JH analog methoprene (Meth) restored egg production. In conclusion, the reproduction roles of ETH, JH, and 20E were investigated in M. separata. These findings will lay the foundation for future research to develop an antagonist that reduces female reproduction and control strategies for pest insects.

A Vision-Based System for In-Sleep Upper-Body and Head Pose Classification.

Sleep quality is known to have a considerable impact on human health. Recent research shows that head and body pose play a vital role in affecting sleep quality. This paper presents a deep multi-task learning network to perform head and upper-body detection and pose classification during sleep. The proposed system has two major advantages: first, it detects and predicts upper-body pose and head pose simultaneously during sleep, and second, it is a contact-free home security camera-based monitoring system that can work on remote subjects, as it uses images captured by a home security camera. In addition, a synopsis of sleep postures is provided for analysis and diagnosis of sleep patterns. Experimental results show that our multi-task model achieves an average of 92.5% accuracy on challenging datasets, yields the best performance compared to the other methods, and obtains 91.7% accuracy on the real-life overnight sleep data. The proposed system can be applied reliably to extensive public sleep data with various covering conditions and is robust to real-life overnight sleep data.

Separation and Enrichment of Alkaloids from Coptidis Rhizoma and Euodiae Fructus by Macroporous Resin and Evaluation of the Effect on Bile Reflux Gastritis Rats.

The Zuojin Pill consists of Coptidis Rhizoma (CR) and Euodiae Fructus (EF). It has been a classic prescription for the treatment of gastrointestinal diseases in China since ancient times. Alkaloids are considered to be its main pharmacologically active substances. The authors of the present study investigated the feasibility of preparing high purity total alkaloids (TAs) from CR and EF extracts separately and evaluated the effect for the treatment of bile reflux gastritis (BRG). Coptis chinensis Franch. and Evodia rutaecarpa (Juss.) Benth. were used in the study. An optimized method for the enrichment and purification of TAs with macroporous resin was established. Furthermore, qualitative analysis by using ultra-high performance liquid chromatography coupled with electrospray ionization and quadrupole-time of flight mass spectrometry (UHPLC-ESI-QTOF-MS) was explored to identify the components of purified TAs. Thirty-one compounds, thirty alkaloids and one phenolic compound, were identified or tentatively assigned by comparison with reference standards or literature data. A method of ultra-high performance liquid chromatography coupled with diode array detector (UHPLC-DAD) for quantitative analysis was also developed. The contents of nine alkaloids were determined. Moreover, a rat model of BRG was used to investigate the therapeutic effect of the combination of purified TAs from CR and EF. Gastric pathologic examination suggested that the alkaloids' combination could markedly attenuate the pathological changes of gastric mucosa.

Simultaneous Qualitative and Quantitative Evaluation of the Coptidis Rhizoma and Euodiae Fructus Herbal Pair by Using UHPLC-ESI-QTOF-MS and UHPLC-DAD.

The herbal pair of Coptidis Rhizoma (CR) and Euodiae Fructus (EF) is a classical traditional Chinese medicine formula used for treating gastro-intestinal disorders. In this study, we established a systematic method for chemical profiling and quantification analysis of the major constituents in the CR-EF herbal pair. A method of ultra high performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) for qualitative analysis was developed. Sixty-five compounds, including alkaloids, phenolics, and limonoids, were identified or tentatively assigned by comparison with reference standards or literature data. The UHPLC fingerprints of 19 batches of the CR-EF herbal pair samples were obtained and the reference fingerprint chromatograms were established. Furthermore, nine compounds among 24 common peaks of fingerprints were considered as marker components, which either had high contents or significant bioactivities, were applied to quality control of the CR-EF herbal pair by quantitative analysis. This UHPLC-DAD analysis method was validated by precision, linearity, repeatability, stability, recovery, and so on. The method was simple and sensitive, and thus reliable for quantitative and chemical fingerprint analysis for the quality evaluation and control of the CR-EF herbal pair and related traditional Chinese medicines.

[Treatment of type 2 diabetic peripheral neuropathy patients of qi-yin deficiency complicated phlegm-dampness blocking collaterals syndrome by internal application of qigui mixture and external application of qigui huoxue lotion: a clinical study].

OBJECTIVE: To evaluate the efficacy of internal application of Qigui Mixture (QM) and external application of Qigui Huoxue Lotion (QHL) in treating type 2 diabetic peripheral neuropathy (DNP) patients of qi-yin deficiency complicated phlegm-dampness blocking collaterals syndrome (QYD-PDBCS), and to primarily discuss its mechanism. METHODS: Totally 62 DPN patients of QYD-PDBCS were randomly assigned to the treatment group (31 cases) and the control group (31 cases). All patients received routine comprehensive therapy. Patients in the control group took Mecobalamine Tablet, 500 microg each time, 3 times per day. Patients in the treatment group additionally took QM, 200 mL per day, twice daily. Besides, they had foot bath in QHL 10 - 15 min every evening for 3 months. The efficacy was assessed by Chinese medical symptom integrals and Toronto clinical scoring system (TCSS) before treatment, 2 and 3 months after treatment. The nerve conduction velocity was determined; the serum levels of total antioxidant capacity (T- AOC), malondialdehyde (MDA), and superoxide dismutase (SOD) were detected 2 and 3 months after treatment. RESULTS: The total effective rates of Chinese medical symptom integrals and TCSS score were obviously higher in the treatment group than in the control group (P < 0.05). The nerve conduction velocity was significantly improved in the treatment group, when compared with before treatment (P < 0.01). There was statistical difference in the nerve conduction velocity difference of right median nerve motor branch, bilateral tibial nerve motor branches, bilateral common peroneal nerve motor branches, bilateral ulnar nerve sensory branches, and left tibial nerve sensory branch (P < 0.05). Compared with before treatment, serum levels of T-AOC and SOD significantly increased, and the level of MDA decreased significantly in the treatment group after 2 and 3 months of treatment (P < 0.01). But only the SOD level increased significantly in the control group (P < 0.01). There was no statistical difference in increased T-AOC level between the two groups after 2 months of treatment (P > 0.05), but there was statistical difference in increased SOD level and decreased MDA level (P < 0.05). There was statistical difference in increased T-AOC and SOD levels and decreased MDA level between the two groups after 3 months of treatment (P < 0.05). No adverse reaction occurred during the therapeutic course. CONCLUSIONS: The internal application of QM and external application of QHL combined with Mecobalamine in treating DPN was safe and effective, with more significant efficacy than using Mecobalamine alone. Its mechanism might be associated with resistance to oxidative stress.

Effect of short neuropeptide F signaling on larval feeding in Mythimna separata.

Mythimna separata is a notorious phytophagous pest which poses serious threats to cereal crops owing to the gluttony of the larvae. Because short neuropeptide F (sNPF) and its receptor sNPFR are involved in a diversity of physiological functions, especially in functions related to feeding in insects, it is a molecular target for pest control. Herein, an sNPF and 2 sNPFRs were identified and cloned from M. separata. Bioinformatics analysis revealed that the sNPF and its receptors had a highly conserved RLRFamide C-terminus and 7 transmembrane domains, respectively. The sNPF and its receptor genes were distributed across larval periods and tissues, but 2 receptors had distinct expression patterns. The starvation-induced assay elucidated that sNPF and sNPFR expression levels were downregulated under food deprivation and recovered with subsequent re-feeding. RNA interference knockdown of sNPF, sNPFR1, and sNPFR2 by injection of double-stranded RNA into larvae not only suppressed food consumption and increased body size and weight, but also led to decrease of glycogen and total lipid contents, and increase of trehalose compared with double-stranded green fluorescent protein injection. Furthermore, molecular docking was performed on the interaction mode between sNPFR protein and its ligand sNPF based on the 3-dimensional models constructed by AlphaFold; the results indicated that both receptors were presumably activated by the mature peptide sNPF-2. These results revealed that sNPF signaling played a considerably vital role in the feeding regulation of M. separata and represents a potential control target for this pest.

Myosteatosis is associated with coronary artery calcification in patients with type 2 diabetes.

BACKGROUND: Myosteatosis, rather than low muscle mass, is the primary etiologic factor of sarcopenia in patients with type 2 diabetes mellitus (T2DM). Myosteatosis may lead to a series of metabolic dysfunctions, such as insulin resistance, systematic inflammation, and oxidative stress, and all these dysfunctions are closely associated with the acceleration of T2DM and atherosclerosis. AIM: To investigate the association between myosteatosis and coronary artery calcification (CAC) in patients with T2DM. METHODS: Patients with T2DM, who had not experienced major cardiovascular events and had undergone both abdominal and thoracic computed tomography (CT) scans, were included. The mean skeletal muscle attenuation was assessed using abdominal CT images at the L3 level. The CAC score was determined from thoracic CT images using the Agatston scoring method. Myosteatosis was diagnosed according to Martin's criteria. Severe CAC (SCAC) was defined when the CAC score exceeded 300. Logistic regression and decision tree analyses were performed. RESULTS: A total of 652 patients with T2DM were enrolled. Among them, 167 (25.6%) patients had SCAC. Logistic regression analysis demonstrated that myosteatosis, age, duration of diabetes, cigarette smoking, and alcohol consumption were independent risk factors of SCAC. Myosteatosis was significantly associated with an increased risk of SCAC (OR = 2.381, P = 0.003). The association between myosteatosis and SCAC was significant in the younger patients (OR = 2.672, 95%CI: 1.477-4.834, P = 0.002), but not the older patients (OR = 1.456, 95%CI: 0.863-2.455, P = 0.188), and was more prominent in the population with lower risks of atherosclerosis. The decision tree analyses prioritized older age as the primary variable for SCAC. In older patients, cigarette smoking was the main contributing factor for SCAC, while in younger patients, it was myosteatosis. CONCLUSION: Myosteatosis is a novel risk factor for atherosclerosis in patients with T2DM, especially in the population with younger ages and fewer traditional risk factors.

[Retracted] MicroRNA­19b promotes the migration and invasion of ovarian cancer cells by inhibiting the PTEN/AKT signaling pathway.

[This retracts the article DOI: 10.3892/ol.2018.8695.].

[Source Apportionment of Morphine in Wastewater].

It is a new approach to identify legal or illegal use of morphine through information on municipal wastewater. However, the sources of morphine in wastewater are complex, and distinguishing the contribution of different sources has become a key issue. A total of 262 influent samples from 61 representative wastewater treatment plants in a typical city were collected from October 2022 to March 2023. The concentrations of morphine, codeine, thebaine, papaverine, noscapine, and monoacetylmorphine were analyzed in wastewater and poppy straws. Combined with the proportion of alkaloids in poppy straws, the source analysis of alkaloids in wastewater was analyzed using the ratio method and positive matrix factorization model (PMF). Only five alkaloids were detected in wastewater, and monoacetylmorphine, a metabolite of heroin, was not detected. The concentrations of morphine and codeine were significantly higher than those of noscapine, papaverine, and thebaine. By constructing the ratios of codeine/(morphine + codeine) and noscapine/(noscapine + codeine), the source of poppy straw could be qualitatively distinguished. The PMF results showed that three sources of morphine for medical use, poppy straw, and codeine contributed 44.9%, 43.7%, and 9.4%, respectively. The different sources varied in these months due to the COVID-19 and influenza A outbreaks, in which the use of drugs containing poppy straws and codeine was the main source, whereas the use of morphine analgesics remained relatively stable. Inventory analysis further demonstrated the reliability of the source contributions from the PMF model, and morphine was not abused in this city.

[Research Progress of Iron Metabolism in Disease Progression and Drug Resistance of Multiple Myeloma--Review].

Iron metabolism is involved in the development and drug resistance of many malignancies, including multiple myeloma (MM). Based on recent studies on iron metabolism and MM, this paper reviews the relationship between iron metabolism and disease process of MM in terms of iron overload leading to ferroptosis in MM cells, the role of iron deficiency in oxidative respiration and proliferation of MM cells, and the interaction between ferroptosis and autophagy in the disease process. The mechanisms by which iron metabolism-related substances lead to MM cells' resistance to proteasome inhibitors (PI) through inducing redox imbalance and M2 macrophage polarization are also briefly described, aiming to provide a theoretical basis for the application of iron metabolism-related drugs to the clinical treatment of MM patients.

Matrix metalloproteinases and tissue inhibitors in multiple myeloma: promote or inhibit?

Matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) play a vital role in the pathogenesis of multiple myeloma (MM), especially for tumor invasion and osteolytic osteopathy. By breaking down extracellular matrix (ECM) components and releasing the proteins composing the ECM and growth factors, as well as their receptors, MMPs affect tissue integrity and promote cancer cell invasion and metastasis. A vital pathophysiological characteristic of MM is the progress of osteolytic lesions, which are brought on by interactions between myeloma cells and the bone marrow microenvironment. MMPs, certainly, are one of the fundamental causes of myeloma bone disease due to their ability to degrade various types of collagens. TIMPs, as important regulators of MMP hydrolysis or activation, also participate in the occurrence and evolution of MM and the formation of bone disease. This review focuses on the role of MMP-1, MMP-2, MMP-7, MMP-9, MMP-13, MMP-14, and MMP-15 and the four types of TIMPs in the invasion of myeloma cells, angiogenesis, osteolytic osteopathy, to offer some novel perspectives on the clinical diagnostics and therapeutics of MM.

Surveillance of COVID-19 and influenza A(H1N1) prevalence in China via medicine-based wastewater biomarkers.

The simultaneous monitoring of individual or multiple diseases can be achieved by selecting therapeutic medicines used to treat the primary symptoms of the condition as biomarkers in wastewater. This study proposes a novel approach to monitor the prevalence of COVID-19 and influenza A (H1N1) by selecting nine medicines to serve as biomarkers, including three antipyretics, three antivirals, and three cough suppressants. To verify our approach, wastewater samples were collected from seventeen urban and five rural wastewater treatment plants (WWTPs) in a Chinese city over a period of one year. The use of antipyretics increased notably during the COVID-19 pandemic, while the consumption of antivirals for influenza A (H1N1) rose in the post-COVID-19 pandemic period, indicating a minor spike in the occurrence of influenza A (H1N1) after the COVID-19 pandemic. Fever is a significant symptom of COVID-19 and can serve as a reliable indicator of disease prevalence. Our research found that the prevalence of COVID-19 in urban areas was significantly higher (at 78.5 %, 95 % CI: 73.4 % - 83.9 %) than in rural areas (with a prevalence of 48.1 %, 95 % CI: 42.4 % - 53.8 %). The prevalence of COVID-19 in urban areas in this study was consistent with the data reported by the Chinese center for Disease Control and Prevention (82.4 %). Continuous monitoring of WWTPs in urban areas with fluctuating populations and complex demographics can provide early disease warning. Our results demonstrate the feasibility of evaluating community disease prevalence by selecting major therapeutic medicines as biomarkers in wastewater.

[Clinical Role of M Protein in Multiple Myeloma and Lymphoma --Review].

M protein is often expressed in multiple myeloma and also can be detected in several lymphoma such as Waldenstrm macroglobulinaemia. M protein level can reflect the malignant degree and even genetic abnormality of multiple myeloma and lymphoma to some extent to predict the progress of the diseases, and the therapeutic response and prognosis of the disease can be evaluated by monitoring the M protein level and its change degree. This article reviews the role of M protein in the progression and prognosis of multiple myeloma and lymphoma, and discusses the differences in M protein expression between multiple myeloma and lymphoma, in order to provide new insights for clinical diagnosis, monitoring and evaluation of therapeutic effect.

Upregulation of LINC01503 promotes cervical cancer progression by targeting the miR-615-3p/CCND1 axis.

Mounting evidence indicates that long non-coding RNAs influence the progression of cervical cancer, but the precise function of LINC01503 in the pathogenesis of the disease remains unknown. Here, we found higher levels of LINC01503 in cervical cancer tissues. High LINC01503 expression was associated with enhanced progression of cervical cancer as indicated by advanced FIGO stage, increased metastasis of tumor cells to lymph nodes, and invasion into deeper cervical tissues. LINC01503 inhibition markedly suppressed the invasion and proliferative ability of tumor cells. Mechanistically, LINC01503 was demonstrated to negatively modulate the expression of miR-615-3p in cervical cancer. CCND1 was found to be a target of miR-615-3p. Rescue experiments indicated that LINC01503 inhibition suppressed the invasion and proliferative ability of the tumor cells, a phenomenon that was reversed following miR-615-3p inhibition or CCND1 overexpression. Collectively, these data indicate that LINC01503 enhances the progression of cervical cancer cells via interaction with miR-615-3p/CCND1 axis.

The primary pulmonary NUT carcinomas and some uncommon somatic mutations identified by next-generation sequencing: a case report.

Nuclear protein in testis (NUT) carcinoma (NUT-C) is an exceedingly rare and aggressive squamous tumor characterized by an acquired rearrangement of the NUT gene involving the NUTM1 (Nut midline carcinoma, family member 1, NUT) gene encoding the nuclear protein of the testis on 15q14. As a rare tumor, there is little information available on the clinicopathologic and molecular cytogenetic findings of NMC. We herein reported a case of a 69-year-old man diagnosed with lung NMC involving the rearrangement of chromosomal region 15q14 harboring the NUTM1 gene. It was exceptionally rare for the patient's involving of the lung but having the chance to be totally resected. After radical surgery, the patient accepted further four cycles of chemotherapy and remains disease-free after 10 months. The immunohistochemical staining of PDL1 was negative and next-generation sequencing technology identified genomic alterations in discoidin domain receptor tyrosine kinase 2 (DDR2), cyclin D1 (CCND1), B-cell leukemia/lymphoma 1 (BCL1), colony-stimulating factor 1 receptor (CSF1R), runt related transcription factor 1 (RUNX1) and death domain-associated protein 6 (DAXX6) from the paraffin-embedded tissue. This case will contribute to not only a better understanding of the molecular mechanism of the primary pulmonary NUT carcinomas but also the potential therapeutic option for the patient.

[Study on the overall anatomical features and clinical value of lumbar nerve root, plexus and branches in CT reconstruction].

OBJECTIVE: To identify the overall anatomical characteristics and the clinical value of the lumbar nerves under CT multiplanar reconstruction. METHODS: Fifty normal subjects and 30 patients with LN diseases (51 sides) were selected, including 10 patients with lumber intervertebral disk hernia, eight patients with spinal stenosis, 5 patients with spondylolisthesis, 1 patient with tethered cord syndrome, 1 patient with lumbar scoliosis, and 5 patients with spinal trauma The 16-slice helical CT (Light Speed, GE Company) was used for scanning the lumbar vertebra with multiplanar reconstruction in Workstation (ADW4.1) with UNIX System in DICOM format. The image was set on the same slice for the overall anatomy and manifestations of the lesions. RESULTS: The same-slice imaging showed the strip-like LN slightly lower than the surrounding muscle in density. Each LN went out of the dural sac at an acute angle. The course of the lumbar plexus and its major branches, including the obturator nerve, femoral nerve and reproductive nerve, and their relations to the adjacent structures were clearly revealed. The percentage of the segments displayed was well associated with the reconstruction angle, with the order being oblique coronal > outward-rotated oblique coronal > oblique sagittal > coronal > sagittal section. The major manifestations of abnormal LN included compression and displacement (50 sides, 98.0%), morphological changes (49 sides, 96.1%), adhesion (41 sides, 80.4%). CONCLUSIONS: The CT multiplanar reconstruction is ideal for the imaging of the overall size, shape, running and tension of the LN root; it is valuable in clinical diagnosis.

Leptomeningeal metastasis after effective first-generation EGFR TKI treatment of advanced non-small cell lung cancer.

OBJECTIVE: To evaluate the influence of a first-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI) treatment on the clinical features of leptomeningeal metastasis (LM) progression and outcome in advanced non-small cell lung cancer (NSCLC) patients. METHODS: We retrospectively evaluated advanced NSCLC patients receiving effective first-generation EGFR TKI treatment (e.g., treatment > 6 months) at our institution between January 2008 and February 2014. Incidence, time to progression, and treatment outcome of LM were examined. RESULTS: In our cohort, 29/420 patients (6.9%) developed LM. Among the patients harboring L858R or deletion of exon 19 in EGFR, the incidence of LM was 10.7% (21/197) and 3.4% (7/203), respectively (P = 0.006). The median time to LM progression was 16.5 months (95% confidence interval (CI), 11.9-20.8). The median overall survival (OS) after LM diagnosis was 5.2 months (95% CI, 3.2-7.2). In a subgroup analysis, OS was improved in patients with performance status (PS) ≤ 2 vs. PS > 2 (14.2 months vs. 2.3 months, respectively; P < 0.001). OS was also improved among patients who received, rather than did not receive, anti-tumor treatment (6.0 months vs. 1.9 months, respectively; P < 0.001) or whole brain radiotherapy (WBRT) (6.0 months vs. 3.9 months, respectively; P = 0.038). Multivariate analysis indicated that WBRT is a good prognostic factor (P = 0.048), whereas best support care (P = 0.033) and PS > 2 (P = 0.034) were poor prognostic factors. CONCLUSION: A greater incidence of LM was observed in NSCLC patients harboring EGFR mutations after effective EGFR TKI treatment. In particular, the primary mutation, L858R, potentially predicts a higher risk of LM compared with deletion of exon 19. These results highlight the importance of determining mutation status when evaluating the biological behavior of LM in NSCLC patients who positively respond to EGFR TKI treatment.

MicroRNA-19b promotes the migration and invasion of ovarian cancer cells by inhibiting the PTEN/AKT signaling pathway.

Local and systemic metastasis is the main reason for the poor survival rate of patients with ovarian cancer (OC). MicroRNAs (miRNAs/miRs) are short non-coding RNAs that serve critical roles in the initiation and progression of OC. The present study demonstrated that expression of miR-19b was significantly increased in OC tissues and cell lines. Analysis of clinicopathological features revealed that the increased expression of miR-19b was associated with advanced International Federation of Gynecology and Obstetrics stage and lymphatic metastasis of OC patients. Loss-of-function experiments demonstrated that the silencing of miR-19b reduced the migration and invasion of OVCAR-3 cells; contrarily, the overexpression of miR-19b facilitated the migration and invasion of CAOV-3 cells. Furthermore, miR-19b regulated the expression of phosphatase and tensin homolog (PTEN) and the activity of the PTEN/RAC serine/threonine-protein kinase pathway in vitro. Notably, the results of dual-luciferase reporter assays indicated that PTEN was a direct downstream target of miR-19b in OC. Taken together, the results of the current study demonstrated that miR-19b serves an oncogenic role in the progression of OC, and could potentially act as a biomarker and therapeutic target for OC patients.

Receptor-binding domain of SARS-Cov spike protein: soluble expression in E. coli, purification and functional characterization.

AIM: Spike protein of coronavirus is responsible for virus binding, fusion and entry, and is a major inducer of neutralizing antibodies. This paper was to find a soluble and functional recombinant receptor-binding domain of severe acute respiratory syndrome-associated coronavirus (SARS-Cov), and to analyze its receptor binding ability. METHODS: Three fusion tags (glutathione S-transferase, GST; thioredoxin, Trx; maltose-binding protein, MBP), which preferably contributes to increasing solubility and to facilitating the proper folding of heteroprotein, were used to acquire the soluble and functional expression of RBD protein in Escherichia coli (BL21(DE3) and Rosetta-gamiB(DE3) strains). The receptor binding ability of the purified soluble RBD protein was then detected by ELISA and flow cytometry assay. RESULTS: RBD of SARS-Cov spike protein was expressed as inclusion body when fused as TrxA tag form in both BL21 (DE3) and Rosetta-gamiB (DE3) under many different cultures and induction conditions. And there was no visible expression band on SDS-PAGE when RBD was expressed as MBP tagged form. Only GST tagged RBD was soluble expressed in BL21(DE3), and the protein was purified by AKTA Prime Chromatography system. The ELISA data showed that GST/RBD antigen had positive reaction with anti-RBD mouse monoclonal antibody 1A5. Further flow cytometry assay demonstrated the high efficiency of RBD's binding ability to ACE2 (angiotensin-converting enzyme 2) positive Vero E6 cell. And ACE2 was proved as a cellular receptor that meditated an initial-affinity interaction with SARS-Cov spike protein. The geometrical mean of GST and GST/RBD binding to Vero E6 cells were 77.08 and 352.73 respectively. CONCLUSION: In this paper, we get sufficient soluble N terminal GST tagged RBD protein expressed in E.coli BL21(DE3); data from ELISA and flow cytometry assay demonstrate that the recombinant protein is functional and binding to ACE2 positive Vero E6 cell efficiently. And the recombinant RBD derived from E.coli can be used to developing subunit vaccine to block S protein binding with receptor and to neutralizing SARS-Cov infection.