Helicobacter pylori and gastric microbiota homeostasis: progress and prospects.

Helicobacter pylori, a Gram-negative microaerobic bacteria belonging to the phylum Proteobacteria, can colonize in the stomach and duodenum, and cause a series of gastrointestinal diseases such as gastritis, gastric ulcer and even gastric cancer. At present, the high diversity of the microorganisms in the stomach has been confirmed with culture-independent methods; some researchers have also studied the stomach microbiota composition at different stages of H. pylori carcinogenesis. Here, we mainly review the possible role of H. pylori-mediated microbiota changes in the occurrence and development of gastric cancer to provide new ideas for preventing H. pylori infection and regulating microecological imbalance.

Huntingtin-associated protein 1 is a potential tumor suppressor for gastric cancer.

BACKGROUND: Gastric cancer is heterogeneous cancer and the causes of this disease are complex. New diagnostic and therapeutic targets are urgently needed to explore. Huntingtin-associated protein 1 (HAP1) is directly related to Huntington's disease (HD). However, patients with Huntington's disease have a lower incidence of cancer. Therefore, we are committed to studying the correlation between HAP1 and gastric carcinogenesis and development. METHODS AND RESULTS: Immunohistochemical staining, western blot analysis, and RT-qPCR were conducted to explore the localization and expression of HAP1 in gastric cancer. To study the biological significance of HAP1, we overexpressed HAP1 in both MKN28 and AGS cell lines by lentivirus infection. To explore the role of HAP1 in cell proliferation, the cells counting assay, EdU incorporation assay, and colony formation assay were carried out. We performed the wound healing assay and transwell assay to study the cell migration and invasion. To further investigate whether HAP1 could regulate gastric cancer cell death during glucose deprivation, Annexin V-FITC/PI staining was performed. In our study, we elucidated that HAP1 was downregulated in gastric cancer. What's more, overexpressing HAP1 inhibited cell proliferation, cell migration and invasion, and triggered apoptosis during glucose deprivation. More importantly, the antitumor properties and mechanisms of HAP1 have been elucidated further in gastric cancer. CONCLUSIONS: Taken together, the available evidence implies that HAP1 may serve as a potential tumor suppressor, making it a significant target in preventing and treating gastric cancer. This research provides a theoretical basis for the early diagnosis, clinical targeted therapy, and prognosis evaluation of gastric cancer.

Roles of microRNAs and exosomes in Helicobacter pylori associated gastric cancer.

Helicobacter pylori (H. pylori) is a common pathogen that infects more than half of the world's population. Its infection can not only lead to a variety of gastrointestinal diseases, such as chronic gastritis and gastric cancer (GC) but also be associated with many extra-gastrointestinal diseases. Exosomes, as a new intercellular information transmission medium, can carry biological signal molecules such as microRNAs (miRNAs) to regulate a variety of cellular physiological activities and are involved in multiple cancer processes. In this article, we provide a systematic review on the role of exosomal miRNAs in H. pylori-associated GC.

[Down-regulation of MDR1 gene expression by CRISPRi to enhance the sensitivity of lung adenocarcinoma A549/DDP cells to cisplatin].

OBJECTIVE: To investigate the effects of down-regulating MDR1 gene expression by CRISPRi on enhancing the sensitivity of lung adenocarcinoma A549/DDP cells to cisplatin. METHODS: The potential CRISPRi interference sites on the MDR1 gene promoter were predicted by bioinformatics software, and the interference fragments were designed and constructed. The mRNA and protein expression levels of MDR1 gene in each group of cells were detected by qRT-PCR and Western blot methods, and the recombinant vectors with high interference efficiency were screened. Human lung cancer A549/DDP cells were divided into three groups: A549/DDP, Scrambed and sgRNA-MDR1-1, with three multiple holes in each group. After each vector was transfected into the cells for 48 h, the efflux of cells in each group was detected by flow cytometry, the IC50 value of cells in each group was detected by MTT method, and the cell morphology of cells treated with cisplatin was observed under laser confocal microscope. RESULTS: After sequencing and comparison, two kinds of CRISPRi recombinant vectors interfering with MDR1 gene transcription were constructed successfully. After transfection of A549/DDP cells, the mRNA and protein levels of MDR1 gene in all transfection groups were decreased significantly (P＜ 0.01). Among them, the interference efficiency of sgRNA-MDR1-1 was the highest, and the interference efficiency of mRNA and protein was 60% and 51%, respectively. After transfection of sgRNA-MDR1-1 vector, compared with the control group, the efflux ability of cells was decreased (P＜0.01), the IC50 value of cells to cisplatin was decreased significantly (P＜0.01), and the intracellular chromatin gathered and marginalized, and apoptotic bodies appeared. CONCLUSION: CRISPRi interference with MDR1 gene in drug-resistant A549/DDP cells can significantly enhance the sensitivity to cisplatin.

[Effects of transcription factor SIX2 gene on the proliferation of bovine skeletal muscle satellite cells].

Objective: To investigate the effect of SIX2 gene on the proliferation of bovine skeletal muscle satellite cells. Methods: Bovine skeletal muscle satellite cells were used as experimental materials, and the expression of SIX2 gene in bovine skeletal muscle satellite cells was detected by real-time quantitative PCR at 24 h, 48 h, and 72 h of proliferation. The SIX2 gene overexpression vector was constructed by homologous recombination. The SIX2 gene overexpression plasmid and the control empty plasmid were transfected into bovine skeletal muscle satellite cells, and each group had three complex Wells. The cell viability was detected by MTT assay at 24 h, 48 h and 72 h after transfection. At 48 h after transfection, the cell cycle was detected by flow cytometry, and the expressions of cell proliferation marker genes were detected by real-time quantitative PCR (qRT-PCR) and Western blot. Results: With the proliferation of bovine skeletal muscle satellite cells, the expression of SIX2 mRNA was increased. Compared with the control group, the expressions of SIX2 mRNA and protein in the SIX2 gene overexpression plasmid group were increased by 18 and 2.6 times, respectively (P＜0.01). The cell viability of the SIX2 gene overexpression plasmid group was increased (P＜0.01), the proportion of G1 cells was decreased by 24.6%, and the proportion of S phase and G2 phase cells was increased by 20.3% and 4.31%, respectively (P＜0.01). The mRNA and protein expressions of Pax7 gene were increased by 15.84 and 1.22 times, respectively, and the mRNA and protein expressions of proliferation marker genes PCNA and CCNB1 were increased by 4.82, 2.23,1.55 and 1.46 times, respectively (P＜0.01). Conclusion: Overexpression of SIX2 gene promotes the proliferation of bovine skeletal muscle satellite cells.

[Effects of Betulinic acid on apoptosis in human gastric cancer SGC-7901 cells].

Objective: To investigate the effects of betulinic acid on apoptosis of human gastric cancer SGC-7901 cells. Methods: The human gastric cancer SGC-7901cells were divided in to 4 groups, and each group was set with 3 replicates. The SGC-7901cells in control group were not treated with betulinic acid; the other 3 experimental groups were treated with betulinic acid at the concentrations of 10, 20 and 30 mg/L, respectively; each group was incubated in a 5% carbon dioxide incubator for 48 h. Laser confocal microscope was used to observe morphological changes of SGC-7901 cells; Flow cytometry was applied to determine apoptosis rate and mitochondrial membrane potential. The mRNA and protein levels of Bcl-2, Bax and Caspase-3 were also detected by qRT-PCR and western blot respectively. Results: Compared with the control group, SGC-7901 cells in the treated group at final concentrations of 10, 20 and 30 mg/L shrinked, appeared apoptosis body along with nuclear splitting. The percentage of cells in early and advanced period of apoptosis were markedly increased (P＜0.05 or P＜0.01), mitochondrial membrane potential was obviously reduced (P＜0.05 or P＜0.01). qRT-PCR and western blot analysis showed that the mRNA and protein expressions of Bax and Caspase-3 were increased significantly (P＜0.01), while the expressions of Bcl-2 were decreased significantly (P＜0.01). Conclusion: Within a certain range of concentrations, betulinic acid induces cell apoptosis by regulating the expression of Bcl-2, Bax and Caspase-3 in human gastric cancer.

[Effects of betulinic acid at different concentrations on autophagy of human gastric cancer MGC-803 cells].

Objective: In this study, human gastric cancer MGC-803 cells were treated with betulinic acid at different concentrations to investigate its effect on cell autophagy. Methods: The human gastric cancer MGC-803 cells were divided into 4 groups, each group was set with 3 replicate. The control group was not treated with betulinic acid, the other three groups were added with final concentration of 10,20,30 mg/L betulinic acid, respectively. Cells were treated with betulinic acid for 48 h,qRT-PCR was applied to detect the effect of betulinic acid on mRNA expressions of autophagy-related genes in human gastric cancer MGC-803 cells. Western blot was performed to determine the protein expressions of cell autophagy-related genes after drug treatment. Immunofluorescence was used to detect the localization and expression of LC3 protein in MGC-803 cells after drug treatment. Results: Compared with the control group,in the concentration range of 10~30 mg/L, the mRNA expression of LC3 and Beclin-1 in human gastric cancer MGC-803 cells treated with betulinic acid were increased significantly, the expressions of Beclin-1 and LC3-Ⅱ protein were also increased significantly, while the expression of LC3-Ⅰ protein was decreased significantly. Among them, betulinic acid at the concentration of 30 mg/L showed the best effects. In addition, betulinic acid induced the LC3 protein in MGC-803 cells to form spot aggregates in the cytoplasm. Conclusion: At the concentrations of 10~30 mg/L, betulinic acid can induce autophagy in human gastric cancer MGC-803 cells.

[Effect of betulinic acid on proliferation of human gastric cancer MGC-803 cell line].

Objective: To investigate the effect of betulinic acid on the proliferation of human gastric cancer MGC-803 cells in vitro. Methods: Human gastric cancer MGC-803 cells were divided into 4 groups, each with 3 multiple holes. Control cells add betulinic acid at a concentration of 0 µg /ml, and the other three experimental groups were added with final concentration of 10, 20, 30 µg/ml Betulinic acid respectively. Cells in each group were incubated in a 5% CO2 incubator for 48 hours, and the Giemsa staining method and trypan blue exclusion method were used to detect the effect of betulinic acid on the cell clone formation rate and growth inhibition rate; EdU method and flow cytometry were used to detect cell proliferation and cell cycle changes; qRT-PCR and Western blot were used to detect the expressions of cell cycle regulators CCNB1 and CCND1. Results: Compared with the control group, the clone formation rate of human gastric cancer MGC-803 cells was significantly reduced (P＜0.01), the growth inhibition rate was significantly increased, and the cell proliferation ability was significantly decreased (P＜0.01); with the increase of betulinic acid concentration in each experimental group the proportion of cells in the G1 phase was gradually decreased, and the number of cells in S phase was increased significantly (P＜0.01); the mRNA and protein expression levels of cell cycle regulators CCNB1 and CCND1 were decreased significantly, and the 30 µg/ml betulinic acid treatment group performed best. Conclusion: At a final concentration of 10～30 µg/ml, betulinic acid can reduce the proliferation of human gastric cancer MGC-803 cells, inhibit cell growth, and down-regulate the expression of CCNB1 and CCND1 to block human gastric cancer MGC-803 cells in the S phase.

[Toosendanin induces apoptosis of human gastric cancer MGC-803 cells and its mechanism].

Objective: To explore the apoptosis of human gastric cancer MGC-803 cells induced by toosendanin(TSN) and its mechanism. Methods: The human gastric cancer MGC-803 cells were divided into 5 groups, each group was set with 3 replicate. Fluorouracil (5-FU) and 0 nmol/L toosendanin (TSN) were used as positive control and negative control, respectively. The other three groups were treated with toosendanin at the final concentrations of 30, 50, and 70 nmol/L, respectively. After 48 h of treatment with toosendanin, the morphology of the cells were observed under laser confocal microscopy. Flow cytometry was used to detect the mitochondrial membrane potential, and enzyme-labeled assays were used to detect the activities of Caspase-3 and Caspase-9. The mRNA and protein levels of Bcl-2, Bax, Cyt c and APAF-1 were measured by qRT-PCR and Western blot. Results: Compared with the 0 nmol/L TSN group, after the human gastric cancer MGC-803 cells were treated with toosendanin at the concentrations of 30, 50, and 70 nmol/L for 48 h, the cell volume shrinkage, nucleus cleavage and chromatin morphological changes were observed under the microscope. The activities of Caspase-3 and Caspase-9 were increased significantly (P＜0.05), while the mitochondrial membrane potential was decreased significantly (P＜0.05). In addition, the mRNA and protein expression levels of Bax, Cyt c and APAF-1 were increased significantly (P＜0.05), while the mRNA and protein expression levels of Bcl-2 were decreased significantly (P＜0.05). Conclusion: Toosendanin up-regulates the expressions of Bax, Cyt c and APAF-1, down-regulates the expression of Bcl-2 gene, enhances the activities of caspase-3 and caspase-9, and induces the apoptosis of human gastric cancer MGC-803 cells.

[Effects of betulinic acid on apoptosis of human gastric cancer MGC-803 cells].

Objective: The effects of betulinic acid (BA) on apoptosis of human gastric cancer MGC-803 cells was investigated by using human gastric cancer MGC-803 cells as experimental materials, and the basis for its clinical application was provided. Methods: The human gastric cancer MGC-803 cells were divided into 4 groups,each group was set with 3 replicates.The control group was MGC-803 cells without being added betulinic acid; the other 3 groups of experimental groups were treated with betulinic acid at final concentrations of 10, 20 and 30 µg /ml respectively. Cells were treated with betulinic acid of different concentrations for 48 h. Laser confocal microscope was used to observe morphological changes of MGC-803. The activities of Caspase-3 and Caspase-9 were detected by an assay kit. Flow cytometry was applied to determine mitochondrial membrane potential. The mRNA and protein levels of Caspase-3, Caspase-9 and Cyt c were also detected by qRT-PCR and Western blot, respectively. Results: Compared with the control group, the activities of Caspase-3 and caspase-9 were increased(P＜0.01), while the mitochondrial membrane potential was decreased significantly(P＜0.01). The mRNA and protein expressions of Caspase-3, caspase-9 and Cyt c were up-regulated significantly(P＜0.01). Conclusion: In the final concentration range of 10 ~ 30 µg/ml, betulinic acid can induce apoptosis of human gastric cancer MGC-803 cells by regulating the expression of Caspase-3, Caspase-9 and Cyt c.

[Effects of hedyotis diffusa on mitochondrial membrane potential and expressions of apoptosis-related genes in human gastric cancer cell line MNK-45].

Objective: To investigate the effects of hedyotis diffusa (injection) on mitochondrial membrane potential and expressions of apoptosis-related genes in human gastric cancer cell line MNK-45 cells. Methods: The human gastric cancer MNK-45 cells were divided into 4 groups, each group was set with 3 replicates. The control group was MNK-45 cells without added hedyotis diffusa; the 3 groups of experimental groups were treated with hedyotis diffusa at final concentrations of 20 , 30, 40 µg / ml respectively; each group was incubated for 48 h in a 5% carbon dioxide incubator, and the morphological changes of the cells were observed under a laser confocal microscope. Mitochondrial membrane potential was detected by flow cytometry. The expressions of Cytochrome C (Cyt c), caspase3 and caspase9 genes and proteins were detected by qRT-PCR and Western blot respectively. Results: Compared with the control group, the mitochondrial membrane potentials of MNK-45 cells were significantly reduced in the hedyotis diffusa treated groups at final concentrations of 20, 30, and 40 µg / ml (P＜0. 01). The gene expressions of Cyt c, caspase3, and caspase9 were significantly up-regulated (P＜0. 01) and their protein expressions were also significantly increased (P＜0. 05 or P＜0. 01). The 40 µg / ml hedyotis diffusa treatment group performed best. Conclusion: In the final concentration range of 20 ~ 40 µg / ml, hedyotis diffusa can reduce human gastric cancer MNK-45 cells mitochondrial membrane potential, induce apoptosis and up-regulate Cyt c, caspase3 and caspase9 gene expressions.

Functional analysis of 4-coumarate: CoA ligase from Dryopteris fragrans in transgenic tobacco enhances lignin and flavonoids.

4-Coumaric acid: coenzyme A ligase (4CL) is a key enzyme in the phenylpropanoid metabolic pathway that regulates the biosynthesis of lignin and flavonoids. Therefore, the study of 4CL is important to explore the accumulation and regulation of metabolites. This study investigated the role that the 4CL2 gene from Dryopteris fragrans (Df4CL2) plays in the metabolite synthesis. Changes in gene expression, enzyme activity, and the content of lignin and flavonoids were measured in different tissues of tobacco as model plant that was successfully transferred with Df4CL2. Tobacco plants with Df4CL2 (transgenic tobacco, TT) were successfully obtained via the Agrobacterium-transformation method. This TT tended to be thicker and had an earlier flowering period than wild type tobacco (WT). The expression levels of Df4CL2 were higher in the stem, leaf, and root in TT compared to WT. In addition, compared to WT, TT had higher 4CL enzyme activity and higher lignin and flavonoids contents. This suggests that Df4CL2 is involved in the synthesis of lignin and flavonoids in D. fragrans. This research provides important evidence toward understanding the phenylpropanoid metabolic pathway in ferns.

virB11 gene potentially involves in ATP metabolism to provide energy in H. pylori infection.

Helicobater pylori (H. pylori) is the most important bacteria known to be associated with various gastroduodenal diseases. virB11 gene is a structural gene of tfs3a genes cluster in the plasticity region of H. pylori. In this study, the structure and biology of virB11 gene were analyzed and elucidated with bioinformatics analysis. After cloning, expression and purification, VirB11 protein was generated for the cytotoxicity to GES-1 cells and the anti-VirB11 protein antibody production for localization and interaction proteins analysis. The results showed that VirB11 protein is a hydrophilic protein, mainly locates in cell membrane. IL-8 productions from GES-1 cells co-culture with VirB11 protein were increased gradually with time (p < 0.001). The interaction proteins of VirB11 protein were F0F1 ATP synthase subunit alpha, ATP synthase subunit beta and isocitrate dehydrogenase. We demonstrate that VirB11 protein possesses cytotoxicity and potentially plays important roles in ATP metabolism to provide energy in the course of H. pylori infection.

[Effect of betulinic acid on proliferation of human gastric cancer SGC-7901 cells].

Objective: Human gastric cancer SGC-7901 cells were treated with betulinic acid(BA)at the concentrations of 0, 10, 20, and 30 µg/ml, and treated with conventional chemotherapeutic drug 5-Fu as a positive control to explore its effect on cell proliferation. Trypan blue and GIEMSA staining method were used to investigate the effect of BA on cell growth inhibition and clone formation. EdU method and flow cytometry were used to explore the proliferation and cell cycle of SGC-7901 cells after treated with BA, respectively. qRT-PCR and Western blot were also applied to determine the mRNA and protein levels of cyclin D1 and cyclin B1. Results: The cell growth inhibition rate was increased after treated with different concentrations of BA in SGC-7901 cells(P＜0.05). After treated for 48 h, BA decreased the clone information and cell proliferation of SGC-7901 cells markedly in dose-and time-dependent manners (P＜0.01). Flow cytometry analysis showed that BA obviously increased the proportion of SGC-7901 cells in G1 phase but decreased the proportion of those in S phase. qRT-PCR and Western blot analysis showed that the mRNA and protein levels of cyclin D1 and cyclin B1 were significantly downregulated by BA at different concentrations(P＜0.01). Compared with the 5-Fu control group, when the concentration of BA was 20 µg/ml and 30 µg/ml, the cell proliferation ability was significantly decreased, the cell cycle was inhibited, and the expression of cyclin was reduced (all P＜0.05). Conclusion: The betulinic acid regulates the proliferation of SGC-7901 cells by inhibiting the expressions of cyclin D1 and cyclin B1, which leads to cell cycle arrest and proliferative inhibition.

[Effects of Toosendanin on the formation of CTPS cytoophidium in human gastric cancer cell MKN-45 and its mechanism].

Objective: To investigate the relationship between toosendanin(TSN) and CTP synthase(CTPS) cytoophidium formation in gastric cancer MKN-45 cells. Methods: In this study, the experimental material is MKN-45 human gastric cancer cells. It contains 7 treatment groups of 0, 20, 40, 60, 80, 100, and 120 nmol/L TSN. Each group was treated in triplex privately for 24、48 and 72 hours. Cell counting kit-8 (CCK8) was used to detect the inhibitory effect of TSN on the proliferation of MKN-45 cells. After immunofluorescence detection, the morphology of CTPS cells was observed by a laser confocal microscope. The effect of TSN on MYC gene expression was detected by qRT-PCR. In addition, it contains 2 treatment groups of 1 mmol/L DON and 1 mmol/L MPA, each group was treated in triplex privately for 6 hours and then the cytoophidium morphology was detected by immunofluorescence. Results: The results of immunofluorescence showed that CTPS formed a filamentous cytoophidium structure after treating MKN-45 cells with 1 mmol/L DON and 1 mmol/L MPA, which means that the cells have the ability to form CTPS cytoophidium; The cell proliferation rate of TSN treatment group was significantly lower than that of 0 nmol / L TSN group (P＜0.01); Immunofluorescence results showed that CTPS cytoophidium was the most abundant in MKN-45 cells after treated with 80 nmol/L TSN for 72 h. The results of qRT-PCR showed that MYC expression in cells was significantly decreased after treated with 80 nmol/L TSN for 24 h (P＜0.05), and MYC expression was significantly increased after 48 h (P＜0.01), and then decreased. Conclusion: Toosendanin may affect intracellular cytoophidium assembling by regulating the expression of MYC.

The diagnostic roles of neutrophil in bloodstream infections.

Bloodstream infections remain a leading cause of death worldwide, despite advances in critical care and understanding of the pathophysiology and treatment strategies. No specific biomarkers or therapy are available for these conditions. Neutrophils play a critical role in controlling infection and it is suggested that their migration and antimicrobial activity are impaired during sepsis which contribute to the dysregulation of immune responses. Recent studies further demonstrated that interruption or reversal of the impaired migration and antimicrobial function of neutrophils improves the outcome of sepsis in animal models. In this review, we provide an overview of the associated diagnostic biomarkers involved neutrophils in sepsis, and discuss the potential of neutrophils as a target to specifically predict the outcome of sepsis.

Interactions between Autophagy and DNA Viruses.

Autophagy is a catabolic biological process in the body. By targeting exogenous microorganisms and aged intracellular proteins and organelles and sending them to the lysosome for phagocytosis and degradation, autophagy contributes to energy recycling. When cells are stimulated by exogenous pathogenic microorganisms such as viruses, activation or inhibition of autophagy is often triggered. As autophagy has antiviral effects, many viruses may escape and resist the process by encoding viral proteins. At the same time, viruses can also use autophagy to enhance their replication or increase the persistence of latent infections. Here, we give a brief overview of autophagy and DNA viruses and comprehensively review the known interactions between human and animal DNA viruses and autophagy and the role and mechanisms of autophagy in viral DNA replication and DNA virus-induced innate and acquired immunity.

[Expression of EGR1 gene and location of EGR1 protein in differentiation of bovine skeletal muscle-derived satellite cells].

OBJECTIVE: To investigate the expression of EGR1 gene and the localization of EGR1 protein in bovine skeletal muscle-derived satellite cells (MDSCs), as well as to investigate the mechanism that EGR1 protein enters the nucleus. METHODS: Bovine MDSCs were cultured in differentiation medium for 1 day, 3 days and 5 days, respectively, and each group was triplicate. The expression of EGR1 gene and the localization of EGR1 protein were studied at different differentiation period in MDSCs by qRT-PC and Western blot. Moreover, the changes on the expression of endogenous EGR1 gene and EGR1 proteins were explored by CRISPRi, site-directed mutagenesis and laser confocal method. RESULTS: The results from the qRT-PCR and Western blot showed that the expressions of EGR1 gene on transcription level and translation level were significantly higher in differentiated cells than those in undifferentiated cells. The highest expression was found on the third day after the differentiation, and then began to decline. Immunofluorescence assays showed that EGR1 proteins were preferentially expressed in differentiated MDSCs, and increased along with the increase of number of myotubes. Confocal observation revealed that some EGR1 proteins were transferred into the nucleus in the differentiation of cells, however, the EGR1 proteins would not be detected in the differentiated MDSCs nuclei if a site directed mutagenesis (serine533) on EGR1 protein occurred. CONCLUSION: During the differentiation of bovine skeletal muscle satellite cells, the transcriptional level of EGR1 gene is increased, and some EGR1 proteins are transferred into the nucleus. The serine phosphorylation at position 533 of the C terminal of EGR1 protein is necessary for the nucleus transfer.

Identification of antigenic domains in the non-structural protein of Muscovy duck parvovirus.

Muscovy duck parvovirus (MDPV) infection is widespread in many Muscovy-duck-farming countries, leading to a huge economic loss. By means of overlapping peptides expressed in Escherichia coli in combination with Western blot, antigenic domains on the non-structural protein (NSP) of MDPV were identified for the first time. On the Western blot, the fragments NS(481-510), NS (501-530), NS (521-550), NS (541-570), NS (561-590), NS (581-610) and NS (601-627) were positive (the numbers in parentheses indicate the location of amino acids), and other fragments were negative. These seven fragments were also reactive in an indirect enzyme-linked immunosorbent assay (i-ELISA). We therefore conclude that a linear antigenic domain of the NSP is located at its C-terminal end (amino acid residues 481-627). These results may facilitate future investigations into the function of NSP of MDPV and the development of immunoassays for the diagnosis of MDPV infection.