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Objective:To analyze the cause and epidemiological characteristics of an outbreak of cutaneous anthrax in Caoxian County, Heze City, Shandong Province, and to provide scientific basis for anthrax prevention and control.Methods:Using on-site epidemiological investigation methods and the "Anthrax Epidemiological Case Investigation Form", case investigations were conducted based on the epidemiological contact history and close contacts of suspected anthrax cases reported by the national health care system ( n = 83). Scorched skin smears, diseased cattle tissues, soil samples from the slaughter site and smears from slaughter utensils were collected from cases for Real-time PCR testing and pathogenic bacteria isolation and culture, respectively. Anthrax determination criteria were carried out with reference to "Anthrax Diagnosis" (WS 283-2020). Results:A total of 13 cases of cutaneous anthrax were found in this outbreak, including 12 clinically diagnosed cases and one confirmed case (positive Real-time PCR test and isolation of a strain of Bacillus anthracis). The epidemiological investigation determined that the source of infection in this outbreak was diseased cattle, the transmission route was through slaughter of diseased cattle, contact with contaminated utensils and related cattle products, and the patients were mainly engaged in occupations related to cattle slaughter or cattle product collection and sale. A total of 84 samples were collected, including 13 skin scabs, 64 environmental samples and 7 beef samples. Thirty-six positive PCR tests were performed, with a positive rate of 42.86% (36/84). Among them, 100.00% (13/13) were positive for skin scab smear specimens, 29.69% (19/64) for environmental samples and 4/7 for beef samples. A total of 8 strains of Bacillus anthracis were isolated, including 6 environmental specimens, 1 suspected case and 1 beef strain, with an overall detection rate of 9.52% (8/84). Eighty-three close contacts were investigated. Thirteen households involved in the epidemic were disinfected by spraying (200 ml/m 2) with chlorine-containing disinfectant (5 000 mg/L), and a total of 40 households involved in the epidemic were disinfected, covering an area of about 10 765 m 2. Forty-five pieces of suspected contaminated clothing were burned and disposed of, and 152 pieces of kitchenware were soaked. Conclusions:Slaughter of infected cattle, contact with contaminated utensils and related cattle products are the main causes of this skin anthrax outbreak. Strengthening market supervision, deepening inter-animal epidemic prevention, carrying out publicity and education on anthrax prevention and control, and enhancing practitioners' awareness of disease prevention is the key to prevent anthrax from occurring.
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Objective@#To investigate the toxic effect of HIV-1 Vpr protein on neurons.@*Methods@#HIV-1 vpr gene was amplified by nested PCR in four parts of peripheral spleen (SPL) and central nervous tissue meninges (MG) of HIV-associated dementia (HAD) patients and non-HAD patients. Eukaryotic expression vector pEGFP-N1-vpr was constructed. The gene sequence and key amino acid sites were analyzed by BLAST and MEGA6. The expression of Vpr protein in N2a cells was detected by Western-blotting. The effects of Vpr proteins from different sources on the activity and cell cycle of N2a cells were studied by flow cytometry.@*Results@#HIV-1 vpr gene was successfully amplified by PCR. Sequence analysis showed that the vpr gene sequence belonged to HIV-1B subtype. There were amino acid mutations at C-terminal 84, 86 and 87 sites of central Vpr protein from HAD and non-HAD patients. Vpr protein could inhibit the activity of nerve cells, leading to G2 phase arrest. Different sources of Vpr had different intensity of action. Compared with other groups, Vpr protein from the meninges of HAD patients showed stronger inhibition of cell activity and G2 phase arrest ability.@*Conclusions@#Variations in key amino acid sites of Vpr protein could cause significant changes in its biological functions, and its significance in the pathogenesis of HAD remains to be further studied.
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Objective@#To investigate the relationship between enterovirus 71 (EV71) and autophagy and the effect of autophagy on viral replication.@*Methods@#RD cells were pretreated with rapamycin, Chloroquine (CQ) and 3-methyladenine (3-MA). The effects of different stages of autophagy on viral replication were detected by Western blotting and plaque assay.@*Results@#The study showed that EV71 infection could induce incomplete autophagy in RD cells. Replication of EV71 was promoted in the CQ treatment group, while the level of replication of the rapamycin and 3-MA treatment groups was reduced. Further studies have shown that mTOR is a key molecule affecting EV71 replication, and inhibition of mTOR by rapamycin can inhibit the synthesis of viral RNA.@*Conclusions@#The effects of different stages of autophagy on viral replication are also different. Inhibition of autophagic lysosome degradation promotes viral replication, while inhibition of the early stage of autophagy or promotion of autophagy reduces the level of viral replication. mTOR can affect the replication of EV71 at RNA level.
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Objective@#To sequence the 3′UTR of enterovirus 71 strains, investigate its foundation and impact in virulence by constructing a 3′UTR-replaced recombinant cDNA infectious clone.@*Methods@#Viral RNA of EV-A71 isolated viruses were extracted, and the nucleotide analysis was performed after sequencing. The 3′UTR of a full-length infectious clone of SDLY107 strain was replaced by its corresponding part of SDLY1 strain, and then the recombinant virus was constructed and identified.@*Results@#The nine isolated strains were classified into sub-genotype C4a of enterovirus (EV)-A71 by analysis, and nucleotide sequence homology for 3′UTR were 94%-100%. 3′UTR of EV-A71 strains may be associated with its pathogenicity. Identification of the rescued virus by sequencing and indirect immunofluorescence confirmed the successful construction of infectious recombinant virus.@*Conclusions@#Sequence analysis indicated that the 3′UTR may be involved in the pathogenicity of EV-A71. The recombinant virus SDLY107(1-3′UTR) was rescued successfully. Our study may provide evidence for further research on the influence of 3′UTR on the virulence of enterovirus 71.
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Hand, foot and mouth disease (HFMD) is a common acute infectious disease among children. Enterovirus 71 (EV71) is one of the major pathogens of HFMD. The incidence of HFMD in our country is higher, the main target population of infection is infants and young children; EV71 is also the most important pathogen causing severe HFMD in children currently. HFMD was classified as notifiable communicable disease of Category C on May 2, 2008. Pathogenesis of HFMD is not yet clear, and there is no drug that can treat such virus effectively. The non-structural protein 3D in EV71, is one of the important targets for the development of anti-EV71 virus drugs, which catalyzes the replication and transcription of the viral genome. This review provides a summary of the structure and function of EV71 3D, which can provide reference for the development of antiviral drugs.
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Objective@#BG-derived HIV-1 Tat protein from an HIV-associated dementia (HAD) patient was expressed in E. coli BL21(DE3) and purified in order to research the effects on human umbilical vein endothelial cells (HUVECs) activity.@*Methods@#The recombinant plasmid pGEX-KG-tat with HIV-1 tat stored in our laboratory was amplified by PCR. The PCR product was cloned into pET-32a-tat. The recombinant plasmid pET-32a-tat was transfected into E. coli, and Tat protein was expressed in BL21(DE3), which was induced by IPTG. Then it was purified by Ni-chelating chromatography column and gel filtration preloaded column, and identified by SDS-PAGE and Western blot(WB). The concentration was determined by BCA Kit. Different concentrations of Tat were added into HUVECs to detect their effects on cell activity by cck-8.@*Results@#The Tat with high purity was efficiently expressed in BL21 (DE3) and obtained by using the Ni-chelating chromatography column and gel filtration preloaded column. The concentration was 0.47 mg/ml by using BCA Kit. As the concentration of Tat increased, HUVECs activity decreased. There was no significant difference in cells viability between negative control with 100 ng/ml and 200 ng/ml group (P>0.05). There was significant difference in cells viability between negative control with 300 ng/ml, 400 ng/ml, 500 ng/ml and 1000 ng/ml group (P<0.05). But the difference between 300 ng/ml, 400 ng/ml, 500 ng/ml and 1000 ng/ml group was not statistically significant (P>0.05).@*Conclusions@#The HIV-1 Tat with biological activity was efficiently expressed in BL21 (DE3), and the activity of HUVECs was significantly decreased when the concentration reached 300 ng/ml.
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Enterovirus 71 (EV71) is one of the important pathogens of hand, foot and mouth disease (HFMD) in infants and young children. It is also a very important and common virus after poliovirus which is associated with severe acute neurological disease. Mutations or spatial structure changes in untranslated regions (UTRs) may affect the ability of the virus to translate and replicate, as well as the affinity of the virus for cellular tissue, and even lead to changes in virulence. At present, the pathogenic mechanism of EV71 is still unknown, and the study of untranslated regions is an indispensable part. Here we briefly review the development of the study of basic structure and function of EV71 untranslated regions in recent years.
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Objective@#To identify the function of 91-112 amino acids (aa) fragment, the interaction domain of head and stalk of Newcastle disease virus(NDV) HN glycoprotein, and clarify the role of the fragment in promoting cell specific membrane fusion.@*Methods@#The specific gene sequences were identified by aligning 91-112 amino acids of NDV HN protein with amino acids of MeV H, RSV G, hPIV3 HN protein. The fragment deletion, fragment substitution and intermolecular homologous recombination method were combined to construct the deletion mutant, De(HN), and three chimeras, Ch(MeV), Ch(RSV), Ch(hPIV3). Cationic transfection reagent was used to transfect the plasmids into baby hamster kidney cells (BHK-21), in which vaccinia virus-T7 RNA polymerase expression system was expressed. Indirect immunofluorescence assay (IIFA) and flow cytometry (FCM) were executed to analyze the cell surface expression level. Cell fusion promotion activity, receptor recognition activity and neuraminidase activity of each mutant were also detected.@*Results@#Cell surface expression efficiency of De(HN) and Ch(MeV), Ch(RSV), Ch(hPIV3) proteins were 9.04%, 82.20%, 70.16%, 75.65% of that of wild-type (wt) HN. Fusion promotion activity of De(HN), Ch(MeV), Ch(RSV), Ch(hPIV3) were 3.83%, 24.76%, 29.42%, 57.84% of that of wt HN. The fusion promotion activity of De(HN) almost disappeared and syncytium couldn’t be found under the microscope. Hemadsorption activity was 13.48%, 36.25%, 34.93%, 65.22%, respectively (P<0.05), which was consistent with the fusion promotion activity of mutant proteins. Neuraminidase activity was 10.81%, 54.42%, 50.13%, 60.35% of that of wt HN, respectively (P<0.05).@*Conclusions@#The amino acids fragment (91-112) of NDV HN protein plays an important role in promotion fusion. The loss of fusion promotion activity of De(HN) protein was related to the failure of effective cell surface expression of the mutant.
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Objective@#To explore the receptor binding specificity of VP8* protein of porcine P[19] rotaviruses (RVs) with oligosaccharides.@*Methods@#The porcine P[19] VP8* protein was expressed and purified. The receptor binding specificity of P[19] VP8* was analyzed by oligosaccharide binding and saliva binding assay.@*Results@#The P[19] VP8* protein showed significant binding to mucin cores, especially mucin core 2.@*Conclusions@#Mucin core 2 may be a potential receptor for the porcine P[19] RV, which provides certain basis for the study of virus infection mechanism and RV surveillance.
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Objective@#To study the sequence characteristics and variation of HIV-1 Vpr gene in different parts of an AIDS dementia complex (ADC) patient and provide basis for the study of the neurologic pathogenesis of HIV-1-assciatd dementia.@*Methods@#Genomic DNA was extracted from peripheral samples (lymph nodes, spleen, liver) and central nervous system (meninges, frontal lobe, temporal lobe gray matter, frontal white matter, basal ganglia cortex) of an ADC patient, The Vpr gene was amplified with nested polymerase chain reaction (PCR). PCR products were cloned into the pMD19-T vector. After transformation into DH5α competent E. coli, five positive clones were sequenced. The phylogenetic tree was built and genetic distance was calculated through MEGA6, and the values of ds/dn was calculated through SNAP, then the changes of the amino acid sites were analyzed.@*Results@#HIV-1 Vpr genes isolated from different tissues of the ADC patient had variations. Vpr HIV-1 gene sequences from central nervous system and peripheral tissues were intercrossed together in the phylogenetic tree. Central nervous system and peripheral HXB2 Vpr had no significant differences in genetic distance. The ds/dn of all the HIV-1 Vpr gene sequences were 3.3749.@*Conclusions@#The HIV-1 Vpr sequences were different in the ADC patient, and there were different variations in different parts of the peripheral and central regions. Whether these variations are related to the pathogenesis of ADC remains to be further studied.
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Objective To compare the degree of cell injury induced by 3D protein (SDLY11 and SDLY107) of enterovirus 71 (EV71) strains.Methods EV71 strains SDLY11 and SDLY107 were respectively isolated from children with mild and severe hand foot mouth disease.The target genes 11-3D-Flag and 107-3D-Flag were amplified by reverse transcription-polymerase chain reation (RT-PCR) and inserted into the eukaryotic expression vector pcDNA3.1.The recombinant plasmids 11-3D-Flag-pcDNA3.1 and 107-3D-Flag-pcDNA3.1 were transformed into Escherichia.coli DH5α, respectively, and were identified by enzyme digestion and sequencing.The recombinant plasmids were transfected into rhabdomyosarcoma (RD) cells, respectively.Expression of 3D protein was detected by indirect immunofluorescence assay and western blot.Cell injury induced by 3D protein was detected with lactate dehydrogenase (LDH) test, cell proliferation was detected by 3-(4,5-dimethylthiazolyl-2)-2,5-diphenylthiazolium bromide (MTT) test, and cell apoptosis was detected with Annexin-V and PI.Multiple comparisons among groups were analyzed using LSD-t test if multiple sets of variables were consistent with homogeneity of variance.If not, Dunnett T3 test was used.Results The 1 400 bp fragments were amplified by reverse tramscription (RT)-polymerase chain reaction (PCR), and the recombinant plasmids were digested by enzyme and the 1 400 bp and 5 400 bp fragments were obtained and identified.Gene sequencing showed that the sequences were consistent with the target genes.The specific fluorescence was observed by indirect immunofluorescence assay, and the western blot showed that the molecular weight of the target protein was 55×103.The LDH test showed that the A490 of SDLY11 3D protein transfection group (0.790±0.048) was higher than that of SDLY107 3D protein transfection group (0.641±0.018).The difference was statistically significant (t=5.14, P<0.05).The cell membrane damage caused by SDLY11 3D protein was more severe than SDLY107 3D protein.The MTT test showed that the A570 of SDLY11 3D protein transfection group (1.028±0.020) was lower than that of SDLY107 3D protein transfection group (1.081±0.002), and the difference was statistically significant (t=3.31, P<0.05).The effect on cell proliferation activity of SDLY11 3D protein was greater than SDLY107 3D protein.The results of Annexin-V/PI showed that the percentage of apoptotic cells of SDLY11 3D protein transfection group and SDLY107 3D protein transfection group were (1.471±0.246)% and (1.465±0.237)%, respectively, and the difference was not statistically significant (t=0.04, P=0.973).Conclusions Compared with the SDLY11 3D protein, SDLY107 3D protein induces slighter cell injury, has weaker effect on cell proliferation activity, and is more favorable for virus replication in cells.
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Enterovirus infection can cause severe disease in human, such as poliovirus can lead to acute flaccid paralysis, coxsackievirus infection can lead to viral myocarditis and aseptic meningitis.Enterovirus 71 infection can lead to cardiopulmonary dysfunction and neurological diseases.In recent years, more and more studies have found that cell autophagy and apoptosis play an important role in the process of enterovirus infection.In this paper, the interactions of autophagy and apoptosis in the process of enterovirus infection are reviewed.
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Objective To construct a chimeric infectious clone of the fatal virulent strain SDLY 107, containing the gene fragments encoding 2A and 3B proteins of the mild virulent strain SDLY 1, and to establish a reverse genetic system platform for further investigation on virulence of enterovirus 71 strains. Methods The overlap PCR analysis was performed to obtain the gene fragments encoding 2A and 3B pro-teins of the mild virulent strain SDLY 1.The obtained gene fragments were digested and then cloned into a plasmid pMD19-T containing the full-length gene of SDLY 107 strain by using gene replacement strategy. The recombinant RNA was transfected into Vero cells for the preparation of recombinant virus particles.Sev-eral assays including the PCR, indirect immunofluorescence ( IFA) , Western blot and sequencing were per-formed for virus identification.Virus titers were measured by 50%cell culture infective dose ( CCID50 ) and plaque assay.Results The infectious clones of SDLY 107-2A-1 and SDLY 107-3B-1 chimeric virus strains were constructed successfully.Typical cytopathic effect was observed in Vero cells after viral transfection. Identification of the rescued viruses by PCR, IFA, Western blot and sequencing further confirmed the suc-cessful construction of infectious virus strains.The virus titers of SDLY 107-2A-1 and SDLY 107-3B-1 strains detected by CCID50 and plaque assay were 1.25 ×105 PFU/ml and 0.7 ×105 PFU/ml, respectively. Conclusion The chimeric viruses SDLY 107-2A-1 and SDLY 107-3B-1 were rescued successfully, causing cytopathic effects similar to those by using the parental virus strain SDLY 107.This study might pave the way for further investigation on in vitro and in vivo virulence of enterovirus 71 strains.
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Enterovirus A71 (EV-A71) causes hand, foot, and mouth disease (HFMD) and various neurological complications, including aseptic meningitis and neurogenic pulmonary edema in young children. HFMD caused by EV-A71 have broken out several times in the Asia-Pacific region since 2007. And it has been a serious threat to public health. There is no effective vaccine or antiviral drug. The pathogenesis of EV-A71 infection is unknown, and EV-A71 3C protein plays an irreplaceable role in replication and anti - innate immunity. Further research on EV-A71 3C protein is conducive to understand the pathogenesis of EV-A71 infection and antiviral drug.
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Animals , Humans , Antiviral Agents , Pharmacology , Enterovirus , Allergy and Immunology , Metabolism , Physiology , Immunity, Innate , Viral Proteins , Chemistry , Genetics , Metabolism , Virus ReplicationABSTRACT
Enterovirus 71 (EV71) is a major causative agent of hand, foot and mouth disease (HFMD). belongs to family Picornaviridae, genus Enterovirus, species A. EV71 infection usually affects subjects aged <5 years. HFMD caused by EV71 infection is usually mild in children. However, in some cases EV71 infection can lead to severe neurogenic disease and even death. EV71 infection has caused epidemic worldwide (especially in the Asia Pacific). HFMD caused by EV71 has become a major public-health prol lem across the Asia Pacific. In EV71 infection, the pathogenesis is determined by viral and host factor, Here, we review research on host susceptibility and how EV71 suppresses immune and intracellular ri
Subject(s)
Animals , Humans , Enterovirus A, Human , Genetics , Virulence , Physiology , Hand, Foot and Mouth Disease , Virology , Virulence , Virus Attachment , Virus ReplicationABSTRACT
Objective To determine the function of conserved amino acids in the fusion-promoting domain of Newcastle disease virus (NDV) hemagglutinin-neuraminidase (HN) protein,clearly understanding mechanism of cell fusion.MethodsUsing a PCR-based site-directed mutagenesis method and the method of homology recombination occurred in vivo to change six conservative amino acids into alanine respectively.Wild type (WT) and all mutant HN proteins were exepressed in BHK-21 cells by the vacciniaT7 RNA polymerase expression system.The amount of each HN protein at the cell surface was determined by fluorescence-activated cell sorter (FACS).Cell fusion efficiency,hemadsorption activity (or receptor binding activity) and neuraminidase activity were determined.Results There was no statistic difference of cell surface expression among WT and each mutant HN protein ( P＜0.05 ).Cell fusion efficiency of each mutant protein decreased to some extent,especially 1103A decreased to 14.2％ in head.Hemadsorption activity of mutant proteins were reduced in different extent,the maximum reduction of which was also 1103A,28.2％ of wt NDV HN.There was different neuraminidase activity among each mutant HN protein.L74A increased slightly to 118.6％.L110A decreased most to 5.2％.I103A decreased second most to 5.7％.Conclusion Conserved amino acids in fusion-promoting domain of NDV HN played an important role in cell fusion.I103 was identified as a key amino acid in this domain.
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Objective To isolate enterovirus 71 from a death children,and analyze whether the neurovirulence was related to the variation of nucleotide and amino acid. Methods Enterovirus 71 was isolated from throat swabs which were colleted from Shandong Linyi People's Hospital. The full length genome was sequenced by amplification with RT-PCR and sequencing of 9 overlapped gene fragments covering full length of the genomes. The nucleotide and amino acid sequenced was aligned by BLAST, Bioedit and MEGA 4. Results A strain of enterovirus 71 was isolated and named as SDLY107. The full length was 7405 bp. The results of homology analysis of overall nucleotide sequence showed that strain Fuyang. Anhui. P. R. C/17.08/2 had highest homology (98.6%)with strain SDLY107, and the homology was 80.0% between strain SDLY107 with prototype strain BrCr/70,and 86. 5% between strain SDLY107 with nerve strain MS/87. Phylogenetic analysis showed that the phylogeny was close between SDLY107 with some isolated strains from Chinese Mainland, such as Beijing, Henan, Guangxi, Sbenzhen, Lanzhou, Fuyang, Chongqing and Zhejiang strains, which was clustered for C4 subtype. The results of amino acid sequence analysis showed that there were 2 mutations, E947D and K1873R, for strain SDLY107. Conclusion SDLY107 belonged to C4 subtype, amino acid mutations E947D and K1873R of which may be relevant to the pathogenicity of EV71.
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Objective To study the variation and characteristics of HIV-1 tat exon 1 gene from a patient with AIDS dementia complex( ADC), so as to research the pathogenesis of ADC. Methods The tat gene was amplified with nested PCR from genomic DNA which was extracted from lymph node, spleen and different brain tissues( meninges, grey matter from frontal cortex, white matter from frontal cortex, temporal cortex and basal ganglia) of a patient who died of ADC. PCR products were cloned into the pGEM-T vector,after transformation and selection by ampicillin and blue/white spotting. Five of positive clones were sequenced. HIV-1 tat sequences were processed with BioEdit and MEGA4. With the softwares, Neighbor-Joining tree, p-Distances, values of ds/dn, and analysis of amino acid motifs were all done. Results The samples were all identified as HIV-1 B and genetic variation exists in HIV-1 tat isolated from different tissue;Compared with HXB2, sixteen sites of the amino acid seque nce coded by the HIV-1 tat gene which was isolated from the patient changed. In addition, part of the changes were different between periphery and brain,especially, the five Q54R changes from basal ganglia and one Q54R change from temporal cortex are deserve to follow with interest. Conclusion Variations exist in the HIV-1 tat genes extracted from the ADC patient and the variations from peripheral and central nerve tissues were different, whether the variations concerned with the pathogenesis of ADC need more research.
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ted in a loss of cell fusion,which suggests the 928 site on G2 is crucial for cell fusion and the fusion peptide is likely on G2.