ABSTRACT
An outbreak of nosocomial infections with Middle East respiratory syndrome coronavirus occurred in South Korea in May 2015. Spike glycoprotein genes of virus strains from South Korea were closely related to those of strains from Riyadh, Saudi Arabia. However, virus strains from South Korea showed strain-specific variations.
Subject(s)
Genetic Variation/genetics , Middle East Respiratory Syndrome Coronavirus/genetics , Spike Glycoprotein, Coronavirus/genetics , Coronavirus Infections/epidemiology , Coronavirus Infections/genetics , Coronavirus Infections/virology , Cross Infection/epidemiology , Cross Infection/virology , Disease Outbreaks , Humans , Male , Republic of Korea/epidemiology , Saudi Arabia/epidemiologyABSTRACT
Pigs are considered to be suitable xenotransplantation organ donors. However, the risk of pathogen transmission from pigs to humans is a major concern in the transplantation of porcine tissues. The porcine endogenous retroviruses (PERVs) PERV-A, PERV-A/C, and PERV-B can infect human cells, but PERV-C is an ecotropic virus infecting only pig cells. Thus, several strategies have been proposed to reduce PERV transmission in xenograft recipients. Human APOBEC3G (huA3G) is a single-strand DNA cytosine deaminase, which inactivates the coding capacity of the virus by deamination of cDNA cytosines to uracils. This reaction occurs within the (-) DNA strand during reverse transcription, resulting in a G-to-A mutation in the (+) strand. While recent data have shown that PERV-B is severely inhibited by huA3G and porcine A3Z2-Z3 (poA3F) in a pseudotype assay, little is known about PERV-C. Here, we compare the antiretroviral activities of huA3G, huA3F and poA3Z2-Z3 against PERV-C. Our data show that APOBEC3 was packaged into PERV-C particles and inhibited PERV-C replication in a dose-dependent manner. PERV-C infectivity was strongly inhibited by poA3Z2-Z3, but it did not markedly reduce PERV-B infectivity. This suggests that PERV-C Gag interacts efficiently with poA3Z2-Z3. In addition, we constructed stably huA3G- and poA3Z2-Z3-expressing 293-PERV-PK-CIRCE cells (human 293 cells infected with PK15-derived PERVs) to examine whether PERV is resistant to poA3Z2-Z3 in a virus-spreading assay. The stably expressed huA3G and poA3Z2-Z3 were more packaging-competent than transiently expressed APOBEC3 proteins. These results suggest that poA3Z2-Z3 can inhibit PERV replication in a pseudotype assay as well as in a virus-spreading assay.
Subject(s)
Cytidine Deaminase/immunology , Cytosine Deaminase/immunology , Endogenous Retroviruses/immunology , Retroviridae Infections/enzymology , Retroviridae/immunology , Swine/immunology , Zoonoses/enzymology , APOBEC-3G Deaminase , Animals , Cytidine Deaminase/genetics , Cytosine Deaminase/genetics , Endogenous Retroviruses/classification , Endogenous Retroviruses/genetics , Endogenous Retroviruses/physiology , Host-Pathogen Interactions , Humans , Retroviridae/classification , Retroviridae/genetics , Retroviridae/physiology , Retroviridae Infections/genetics , Retroviridae Infections/immunology , Retroviridae Infections/virology , Swine/genetics , Swine/virology , Transplantation, Heterologous , Zoonoses/genetics , Zoonoses/immunology , Zoonoses/virologyABSTRACT
Transgenic potatoes expressing glyceraldehyde-3-phosphate dehydrogenase (GPD), isolated from the oyster mushroom, Pleurotus sajor-caju, had increased tolerance to salt stress (Jeong et al. Biochem Biophys Res Commun 278:192-196, 2000). To examine the physiological mechanisms enhancing salt tolerance in GPD-transgenic rice plants, the salt tolerance of five GPD transgenic rice lines (T1-T5) derived from Dongjin rice cultivar were evaluated in a fixed 150 mM saline environment in comparison to two known wild-type rice cultivars, Dongjin (salt sensitive) and Pokali (salt tolerant). Transgenic lines, T2, T3, and T5, had a substantial increase in biomass and relative water content compared to Dongjin. Stomatal conductance and osmotic potential were higher in the GPD transgenic lines and were similar to those in Pokali. The results are discussed based on the comparative physiological response of GPD transgenic lines with those of the salt-sensitive and salt-tolerant rice cultivars.
Subject(s)
Glyceraldehyde-3-Phosphate Dehydrogenases/genetics , Oryza/physiology , Pleurotus/enzymology , Pleurotus/genetics , Salt Tolerance , Biomass , DNA, Bacterial/genetics , Darkness , Glyceraldehyde-3-Phosphate Dehydrogenases/metabolism , Oryza/genetics , Osmosis , Plant Stomata/physiology , Plants, Genetically Modified , Stress, Physiological , WaterABSTRACT
Foot-and-mouth disease virus (FMDV) is a highly contagious virus that affects cloven-hoofed animals and causes severe economic losses in the livestock industry. Given that this high-risk pathogen has to be handled in a biosafety level (BSL)-3 facility for safety reasons and the limited availability of BSL-3 laboratories, experiments on FMDV call for more attention. Therefore, we aimed to develop an FMDV experimental model that can be handled in BSL-2 laboratories. The NanoBiT luciferase (Nano-luc) assay is a well-known assay for studying protein-protein interactions. To apply the NanoBiT split luciferase assay to the diagnosis and evaluation of FMD, we developed an inactivated HiBiT-tagged Asia1 Shamir FMDV (AS-HiBiT), a recombinant Asia1 shamir FMDV with HiBiT attached to the VP1 region of Asia1 shamir FMDV. In addition, we established LgBiT-expressing LF-BK cell lines, termed LgBit-LF-BK cells. It was confirmed that inactivated AS-HiBiT infected LgBiT-LF-BK cells and produced a luminescence signal by binding to the intracellular LgBiT of LgBiT-LF-BK cells. In addition, the luminescence signal became stronger as the number of LgBiT-LF-BK cells increased or the concentration of inactivated AS-HiBiT increased. Moreover, we confirmed that inactivated AS-HiBiT can detect seroconversion in sera positive for FMDV-neutralizing antibodies. This NanoBiT split luciferase assay system can be used for the diagnosis and evaluation of FMD and expanded to FMD-like virus models to facilitate the evaluation of FMDV vaccines and antibodies.
Subject(s)
Foot-and-Mouth Disease Virus , Foot-and-Mouth Disease , Animals , Antibodies, Neutralizing/blood , Antibodies, Neutralizing/immunology , Antibodies, Viral/blood , Antibodies, Viral/immunology , Cell Line , Foot-and-Mouth Disease/diagnosis , Foot-and-Mouth Disease/virology , Foot-and-Mouth Disease Virus/genetics , Luciferases/genetics , Luciferases/metabolismABSTRACT
Indeterminate domain (IDD) genes are a family of plant transcriptional regulators that function in the control of development and metabolism during growth. Here, the function of Oryza sativa indeterminate domain 10 (OsIDD10) has been explored in rice plants. Compared with wild-type roots, idd10 mutant roots are hypersensitive to exogenous ammonium. This work aims to define the action of IDD10 on gene expression involved in ammonium uptake and nitrogen (N) metabolism. The ammonium induction of key ammonium uptake and assimilation genes was examined in the roots of idd10 mutants and IDD10 overexpressors. Molecular studies and transcriptome analysis were performed to identify target genes and IDD10 binding cis-elements. IDD10 activates the transcription of AMT1;2 and GDH2 by binding to a cis-element motif present in the promoter region of AMT1;2 and in the fifth intron of GDH2. IDD10 contributes significantly to the induction of several genes involved in N-linked metabolic and cellular responses, including genes encoding glutamine synthetase 2, nitrite reductases and trehalose-6-phosphate synthase. Furthermore, the possibility that IDD10 might influence the N-mediated feedback regulation of target genes was examined. This study demonstrates that IDD10 is involved in regulatory circuits that determine N-mediated gene expression in plant roots.
Subject(s)
Oryza/genetics , Plant Proteins/physiology , Quaternary Ammonium Compounds/pharmacology , Transcription Factors/physiology , Amino Acid Sequence , Gene Expression Profiling , Gene Expression Regulation, Plant/drug effects , Glutamine/pharmacology , Methionine Sulfoximine/pharmacology , Molecular Sequence Data , Mutagenesis, Insertional , Nitrogen/metabolism , Oryza/drug effects , Oryza/metabolism , Phenotype , Plant Proteins/genetics , Plant Proteins/metabolism , Plant Roots/drug effects , Plant Roots/genetics , Plant Roots/metabolism , Sequence Alignment , Transcription Factors/genetics , Transcription Factors/metabolismABSTRACT
Temporal and spatial variation in the levels of and sensitivity to hormones are essential for the development of higher organisms. Traditionally, end-product feedback regulation has been considered as the key mechanism for the achievement of cellular homeostasis. Brassinosteroids (BRs) are plant steroid hormones that are perceived by the cell surface receptor kinase Brassinosteroid Insensitive1. Binding of these hormones to the receptor activates BR signaling and eventually suppresses BR synthesis. This report shows that RAVL1 regulates the expression of the BR receptor. Furthermore, RAVL1 is also required for the expression of the BR biosynthetic genes D2, D11, and BRD1 that are subject to BR negative feedback. Activation by RAVL1 was coordinated via E-box cis-elements in the promoters of the receptor and biosynthetic genes. Also, RAVL1 is necessary for the response of these genes to changes in cellular BR homeostasis. Genetic evidence is presented to strengthen the observation that the primary action of RAVL1 mediates the expression of genes involved in BR signaling and biosynthesis. This study thus describes a regulatory circuit modulating the homeostasis of BR in which RAVL1 ensures the basal activity of both the signaling and the biosynthetic pathways.
Subject(s)
Oryza/metabolism , Plant Growth Regulators/biosynthesis , Plant Proteins/metabolism , Steroids, Heterocyclic/metabolism , Amino Acid Sequence , Base Sequence , Gene Expression Regulation, Plant , Homeostasis , Molecular Sequence Data , Oryza/genetics , Plant Proteins/genetics , Protein Serine-Threonine Kinases/metabolism , RNA, Plant/genetics , Signal Transduction , Transformation, GeneticABSTRACT
KEY MESSAGE: Overexpression of OsGS gene modulates oxidative stress response in rice after exposure to cadmium stress. Our results describe the features of transformants with enhanced tolerance to Cd and abiotic stresses. Glutamine synthetase (GS) (EC 6.3.1.2) is an enzyme that plays an essential role in the metabolism of nitrogen by catalyzing the condensation of glutamate and ammonia to form glutamine. Exposure of plants to cadmium (Cd) has been reported to decrease GS activity in maize, pea, bean, and rice. To better understand the function of the GS gene under Cd stress in rice, we constructed a recombinant pART vector carrying the GS gene under the control of the CaMV 35S promoter and OCS terminator and transformed using Agrobacterium tumefaciens. We then investigated GS overexpressing rice lines at the physiological and molecular levels under Cd toxicity and abiotic stress conditions. We observed a decrease in GS enzyme activity and mRNA expression among transgenic and wild-type plants subjected to Cd stress. The decrease, however, was significantly lower in the wild type than in the transgenic plants. This was further validated by the high GS mRNA expression and enzyme activity in most of the transgenic lines. Moreover, after 10 days of exposure to Cd stress, increase in the glutamine reductase activity and low or no malondialdehyde contents were observed. These results showed that overexpression of the GS gene in rice modulated the expression of enzymes responsible for membrane peroxidation that may result in plant death.
Subject(s)
Cadmium/pharmacology , Glutamate-Ammonia Ligase/metabolism , Oryza/physiology , Oxidative Stress , Amino Acid Sequence , Base Sequence , Gene Expression Regulation, Plant , Glutamate-Ammonia Ligase/genetics , Hydrogen Peroxide/metabolism , Lipid Peroxidation , Malondialdehyde/metabolism , Molecular Sequence Data , Oryza/enzymology , Oryza/genetics , Plant Leaves/enzymology , Plants, Genetically Modified/enzymology , Plants, Genetically Modified/genetics , Plants, Genetically Modified/physiology , Promoter Regions, GeneticABSTRACT
The development of quantum dot (QD)-based modular bioprobe that has a compact size and enable a facile conjugation of various biofunctional groups is in high demand. To address this, we surface engineered QDs with zwitterion polymer ligands to have an inherent compact size and derivatized them sequentially with the recombinant proteins SpyCatcher/SpyTag (SC/ST) to use their protein ligation system. SC/ST spontaneously form one complex through the isopeptide bond between them. SC-conjugated QDs (QD-SC) were used as base building blocks. Then, ST-biomolecules were added for modular biofunctionalization. We synthesized compact sized (â¼15 nm) QD-SC-ST-affibody (antibody-mimicking small protein for tumor detection) conjugates, which showed successful cell-receptor targeting. The target cell-receptor could be easily tuned by changing the type of ST-affibody. We also demonstrated that anti-human-chorionic-gonadotropin mouse IgG1 antibodies can be labeled on the QD surface by mixing QD-SC with the ST-MG1Nb (mouse-IgG1-specific protein). The immunoassay performance of the antibody-labeled QDs was evaluated using a pregnancy test kit, displaying equivalent detection sensitivity to a commercially available kit. This study proposed an innovative strategy for QD biofunctionalization in a modular manner, which can be expanded to a diverse range of colloidal particle derivatization.
Subject(s)
Quantum Dots , Mice , Animals , Polymers , Recombinant Proteins/chemistry , Immunoglobulin GABSTRACT
Following the worst outbreak of foot-and-mouth disease (FMD), a highly contagious disease in cloven-hoofed animals caused by the FMD virus, from November 2010-April 2011, the Korean government enforced a mandatory vaccination policy. A bivalent (FMD type O and A; O + A) vaccine has been recently implemented. Although the FMD outbreak was suppressed by vaccination, the intramuscular (IM) injection presents side effects. Therefore, improving FMD vaccine quality is necessary. Here, we investigated the side effects and immune efficacy of the O + A bivalent vaccine using two different routes of administration: intradermal (ID) and IM. To compare the immune efficacy of the two inoculation routes, virus neutralization titers and structural protein (antigen) levels were measured. The protective efficacy of ID vaccines was confirmed using two viruses (FMDV O/AS/SKR/2019 and A/GP/SKR/2018) isolated in the Republic of Korea. Serological analysis revealed that both animals administered by ID and IM injections exhibited equal immune efficacy. A virus challenge test in the target animal (swine) revealed no (or extremely low) clinical symptoms. Swine in the ID injected group exhibited no side effects. In conclusion, we suggest that the ID route of vaccination is an effective alternative to the existing IM route, which is associated with more frequent side effects.
ABSTRACT
Foot-and-mouth disease (FMD) is a fatal contagious viral disease that affects cloven-hoofed animals and causes severe economic damage at the national level. There are seven serotypes of the causative foot-and-mouth disease virus (FMDV), and type O is responsible for serious outbreaks and shows a high incidence. Recently, the Cathay, Southeast Asia (SEA), and ME-SA (Middle East-South Asia) topotypes of type O have been found to frequently occur in Asia. Thus, it is necessary to develop candidate vaccines that afford protection against these three different topotypes. In this study, an experimental FMD vaccine was produced using a recombinant virus (TWN-JC) with the JC epitope (VP1 140-160 sequence of the O/SKR/Jincheon/2014) between amino acid 152 and 153 of VP1 in TWN-R. Immunization with this novel vaccine candidate was found to effectively protect mice against challenge with the three different topotype viruses. Neutralizing antibody titers were considerably higher after a second vaccination. The serological differences between the topotype strains were identified in guinea pigs and swine. In conclusion, a significant serological difference was observed at 56 days post-vaccination between animals that received the TWN-JC vaccine candidate and those that received the positive control virus (TWN-R). The TWN-JC vaccine candidate induced IFNγ and IL-12B.
ABSTRACT
BACKGROUND AND AIM: Ectopic pancreas is a common submucosal lesion in the stomach, but its histological diagnosis is usually difficult when tissue samples are obtained with a conventional biopsy forceps. The aim of this study was to describe the endosonographic features of gastric ectopic pancreas. METHODS: We retrospectively analyzed a database of all patients who underwent endoscopic ultrasonography (EUS) at Pusan National University Hospital from July 2006 to August 2010. A total of 26 patients with histologically confirmed ectopic pancreas were included in the study. The EUS features of their lesions were analyzed. RESULTS: Ten lesions were located in the antrum, and 16 lesions were located in the body. Nine lesions (34.6%) showed an umbilication or central dimpling on the surface, and a mural growth pattern was most commonly observed (61.5%). Twenty-four lesions (92.3%) showed hypoechoic echogenicity, and 13 lesions (50.0%) were heterogeneous. The borders were indistinct in 16 lesions (61.5%) and lobulated margins were observed in 16 lesions (61.5%). Anechoic cystic or tubular structures appeared in 17 lesions (65.4%), and 20 lesions (76.9%) involved two or more sonographic layers. CONCLUSIONS: The characteristic EUS features of ectopic pancreas are indistinct borders, lobulated margins, presence of anechoic duct-like structures, a mural growth pattern, and localization within two or more layers. These EUS features are potentially useful for differentiating ectopic pancreas from other mesenchymal tumors in the stomach.
Subject(s)
Choristoma , Endosonography , Pancreas , Stomach Diseases/diagnostic imaging , Adolescent , Adult , Aged , Biopsy , Chi-Square Distribution , Diagnosis, Differential , Female , Humans , Male , Middle Aged , Predictive Value of Tests , Republic of Korea , Retrospective Studies , Stomach Neoplasms/diagnostic imaging , Young AdultABSTRACT
Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is the most common form of primary extranodal lymphomas. In most cases, it is developed as multifocal and mucosal lesions, and its initial diagnosis is made by biopsy of suspicious lesions on endoscopy. However, when gastric MALT lymphoma afflict submucosal site without typical mucosal lesion, further procedures are necessary for diagnosis, such as endoscopic mucosal resection and endoscopic ultrasonography. We recently experienced two cases of submucosal tumor-like gastric MALT lymphoma. Both cases were without any mucosal lesion. One case was confirmed by endoscopic mucosal resection, and the latter was by wedge resection. Treatment modalities included endoscopic mucosal resection, surgery, H. pylori eradication, and/or chemotherapy. Both cases achieved complete remission until our 18 months' and 16 months' follow up.
Subject(s)
Gastric Mucosa/pathology , Lymphoma, B-Cell, Marginal Zone/diagnosis , Anti-Bacterial Agents/therapeutic use , Endosonography , Female , Gastroscopy , Helicobacter Infections/drug therapy , Helicobacter pylori , Humans , Lymphoma, B-Cell, Marginal Zone/pathology , Lymphoma, B-Cell, Marginal Zone/surgery , Male , Middle Aged , Stomach Neoplasms/diagnosisABSTRACT
BACKGROUND/AIMS: It is difficult to clinically and endoscopically differentiate intestinal tuberculosis (ITB) and Crohns disease (CD). The aim of this study was to evaluate the usefulness of in vitro interferon-gamma (INF-gamma) assay for differential diagnosis between ITB and CD. METHODS: Sixty patients for whom differential diagnosis between ITB and CD was difficult were enrolled between January 2007 and January 2009. The INF-gamma-producing T-cell response to early secreted antigenic target 6 and culture filtrate protein 10 were measured by T-SPOT.TB blood test in vitro. We evaluated the usefulness of T-SPOT.TB blood test by comparing its results with the final diagnosis. RESULTS: Twenty and forty patients were revealed to be positive and negative in T-SPOT.TB blood test, respectively. Of the 20 patients found to be positive, 12 patients (60%) were finally diagnosed as ITB, 6 patients as CD, and 2 patients as Behcets enterocolitis. Of the 40 patients with negative results, 38 patients (95%) were diagnosed as CD; one as Behcets enterocolitis; one as nonspecific colitis; none as ITB. The sensitivity and specificity of T-SPOT.TB blood test for ITB were 100% and 83.3%, respectively. Positive and negative predictive values of T-SPOT.TB blood test for ITB were 60.0% and 100%, respectively. CONCLUSIONS: When differential diagnosis between ITB and CD is difficult, T-SPOT.TB blood test may be a helpful and rapid diagnostic tool to exclude ITB. Prospective large-scaled studies are required for further evaluation of the usefulness of T-SPOT.TB blood test for differential diagnosis between ITB and CD.
Subject(s)
Crohn Disease/diagnosis , Interferon-gamma/blood , Tuberculosis, Gastrointestinal/diagnosis , Adolescent , Adult , Aged , Diagnosis, Differential , Female , Humans , Male , Middle Aged , Polymerase Chain Reaction , Reagent Kits, Diagnostic , Retrospective StudiesABSTRACT
Indeterminate 1 (Id1), a classical flowering gene first reported in 1946, is one of the earliest genes whose expression in leaf tissues affects the floral transition in the shoot meristem. How Id1 is integrated into the flowering process is largely unknown. In this study, we examined the genetic action of the rice (Oryza sativa) ortholog OsId1. In rice, OsId1 is preferentially expressed in young leaves, but the overall expression pattern is broader than that in maize (Zea mays). OsId1 is able to activate transcription in yeast. RNAi mutants show a delay in flowering under both short-day (SD) and long-day (LD) conditions. OsId1 regulates the expression of Ehd1 (Early heading date 1) and its downstream genes, including Hd3a (a rice ortholog of FT) and RFT1 (Rice Flowering Locus T1), under both SD and LD conditions. In rice, the expression of Ehd1 is also controlled by the photoperiodic flowering genes OsGI (a rice ortholog of GI) and OsMADS51. However, the expression of OsId1 is independent of OsGI, OsMADS51, and OsMADS50 (a rice SOC1 ortholog). This study demonstrates that the activation of Ehd1 by OsId1 is required for the promotion of flowering.
Subject(s)
Flowers/metabolism , Oryza/genetics , Photoperiod , Plant Proteins/metabolism , Transcription Factors/metabolism , Amino Acid Sequence , Flowers/genetics , Gene Expression Regulation, Plant , Genes, Plant , Molecular Sequence Data , Oryza/metabolism , Plant Leaves/genetics , Plant Leaves/metabolism , Plant Proteins/genetics , Plants, Genetically Modified/genetics , Plants, Genetically Modified/metabolism , RNA Interference , RNA, Plant/genetics , Sequence Alignment , Transcription Factors/genetics , Transformation, GeneticABSTRACT
Retrovirus tropism can be restricted by host cell factors such as Fv1, TRIM5alpha, and Lv1 that inhibit infection by targeting the incoming viral capsid. The Fv1 gene inhibits murine leukemia virus infection in mice, but the precise mechanism of Fv1-mediated restriction is poorly understood. Our previous studies had demonstrated that Fv1-mediated viral tropism can be determined within the capsid protein at position 114 (Jung and Kozak. 2000. J. Virol. 74: 5385-7). To study the interaction between Fv1 and CA, we introduced amino acid substitution and deletion at this site in the N-tropic AKV capsid gene. The mutated two-LTR proviral DNAs were introduced into SC-1 cells by transfection. After transfection, cell supernatants collected from transfected cells were tested for host range susceptibility. The result indicated that substitution of amino acids did not alter tropism, but the deletion of 114His produced a virus with unusual tropism. The novel phenotype produced here failed to replicate in Fv1-expressing cells. This mutant virus showing such an extreme restriction pattern would be useful for studying the mechanism of Fv1- mediated restriction.
Subject(s)
Gene Products, gag/metabolism , Leukemia Virus, Murine/physiology , Proteins/metabolism , Tropism , Amino Acid Substitution , Animals , Capsid Proteins/genetics , Capsid Proteins/metabolism , Cell Line , Gene Products, gag/genetics , Leukemia Virus, Murine/genetics , Mice , Mice, Inbred BALB C , Mutagenesis, Site-Directed , NIH 3T3 Cells , Proteins/genetics , Terminal Repeat Sequences , Transfection , Virus ReplicationABSTRACT
Clone PERV-C (A3) env was isolated from the genomic DNA of domestic pig (Sus scrofa domesticus) in Korea to investigate the molecular properties of PERV-C. The nucleic acid homologies between the PERV-MSL (type C) reference and the PERV-C(A3) clone was 99% for env, but a single base pair deletion was found in the transmembrane (TM) region of the env open reading frame. To examine the functional characteristics of truncated PERV-C env, we constructed a replication-incompetent retroviral vector by replacing the env gene of the pCL-Eco retrovirus vector with PERV-C env. A retroviral vector bearing PERV-C/A chimeric envelopes was also created to complement the TM defect. Our results indicated that truncated PERV-C env was not infectious in human cells as expected. Interestingly, however, the vector with the PERV-C/A envelope was able to infect 293 cells. This observation suggests that recombination within PERV-C TM could render PERV-C infectious in humans. To further characterize PERV-C/A envelopes, we constructed an infectious molecular clone by using a PCR-based technique. This infectious molecular clone will be useful to examine more specific regions that are critical for human cell tropism.
Subject(s)
Retroviridae Infections/virology , Retroviridae/genetics , Sus scrofa/virology , Viral Envelope Proteins/genetics , Amino Acid Sequence , Animals , Cell Line , Cloning, Molecular , Disease Reservoirs/virology , Humans , Korea , Molecular Sequence Data , Point Mutation , Recombination, Genetic , Retroviridae/chemistry , Retroviridae/metabolism , Sequence Alignment , Viral Envelope Proteins/chemistry , Viral Envelope Proteins/metabolismABSTRACT
OBJECTIVES: The rates of asymptomatic infection with Middle East Respiratory Syndrome (MERS) coronavirus vary. A serologic study was conducted to determine the asymptomatic MERS infection rate in healthcare workers and non-healthcare workers by exposure status. METHODS: Study participants were selected from contacts of MERS patients based on a priority system in 4 regions strongly affected by the 2015 MERS outbreak. A sero-epidemiological survey was performed in 1,610 contacts (average duration from exposure to test, 4.8 months), and the collected sera were tested using an enzyme-linked immunespecific assay (ELISA), immunofluorescence assay (IFA), and plaque reduction neutralization antibody test (PRNT). Among the 1,610 contacts, there were 7 ELISA-positive cases, of which 1 exhibited positive IFA and PRNT results. RESULTS: The asymptomatic infection rate was 0.060% (95% confidence interval, 0.002 to 0.346). The asymptomatic MERS case was a patient who had been hospitalized with patient zero on the same floor of the hospital at the same time. The case was quarantined at home for 2 weeks after discharge, and had underlying diseases, including hypertension, angina, and degenerative arthritis. CONCLUSIONS: The asymptomatic infection was acquired via healthcare-associated transmission. Thus, it is necessary to extend serologic studies to include inpatient contacts who have no symptoms.
Subject(s)
Asymptomatic Diseases/epidemiology , Coronavirus Infections/epidemiology , Cross Infection/epidemiology , Disease Outbreaks , Health Personnel/statistics & numerical data , Enzyme-Linked Immunosorbent Assay , Humans , Middle East Respiratory Syndrome Coronavirus/isolation & purification , Republic of Korea/epidemiology , Seroepidemiologic StudiesABSTRACT
Even though Ac/Ds gene-tagging systems have been established in many higher plants, maize is the only major plant in which short-distance transposition of Ac/Ds has been utilized to probe gene function. This study was performed to evaluate the efficiency of obtaining new alleles and functional revertants from Ds insertion loci in rice. By analyzing 1,580 plants and the progeny of selected lines, the insertion sites and orientations of Ds elements within 16 new heritable alleles of three rice loci were identified and characterized. Intragenic transposition was detected in both directions from the original insertion sites. The closest interval was 35 bp. Three of the alleles had two Ds elements in cis configuration in the same transcription units. We also analyzed the excision footprints of intragenic and extragenic transpositions in Ds-inserted alleles at 5 loci. The 134 footprints obtained from different plants revealed predominant patterns. Ds excision at each locus left a predominant footprint at frequencies of 30-75%. Overall, 66% of the footprints were 7-bp additions. In addition, 16% of the excisions left 0-, 3-, 6-, and 9-bp additions with the potential of conserving reading frame.
Subject(s)
Alleles , DNA Transposable Elements , Genetic Variation , Mutagenesis, Insertional , Zea mays/genetics , Base Sequence , DNA, Plant/genetics , DNA, Plant/metabolism , Gene Expression Regulation, Plant , Genes, PlantABSTRACT
The murine ecotropic retroviral receptor has been demonstrated to function as a mouse cationic amino acid transporter 1 (mCAT1), and is comprised of multiple membranespanning domains. Feral mouse (Mus dunni) cells are not susceptible to infection by the ecotropic Moloney murine leukemia virus (MoMLV), although they can be infected by other ecotropic murine leukemia viruses, including Friend MLV and Rauscher MLV. The relative inability of MoMLV to replicate in M. dunni cells has been attributed to two amino acids (V214 and G236) located within the third extracellular loop of the M. dunni CAT1 receptor (dCAT1). Via the exchange of the third extracellular loop of the mCAT1 cDNA encoding receptor from the permissive mouse and the corresponding portion of cDNA encoding for the nonpermissive M. dunni receptor, we have identified the most critical amino acid residue, which is a glycine located at position 236 within the third extracellular loop of dCAT1. We also attempted to determine the role of the third extracellular loop of the M. dunni CAT1 receptor with regard to the formation of the syncytium. The relationship between dCAT1 and virus-induced syncytia was suggested initially by our previous identification of two MLV isolates (S82F in Moloney and S84A in Friend MLV), both of which are uniquely cytopathic in M. dunni cells. In an attempt to determine the relationship existing between dCAT1 and the virally-induced syncytia, we infected 293-dCAT1 or chimeric dCAT1 cells with the S82F pseudotype virus. The S82F pseudotype virus did not induce the formation of syncytia, but did show increased susceptibility to 293 cells expressing dCAT1. The results of our study indicate that S82F-induced syncytium formation may be the result of cell-cell fusion, but not virus-cell fusion.
Subject(s)
Cationic Amino Acid Transporter 1/chemistry , Giant Cells/physiology , Moloney murine leukemia virus/pathogenicity , Receptors, Virus/chemistry , 3T3 Cells , Amino Acid Sequence , Animals , Cationic Amino Acid Transporter 1/metabolism , Cell Fusion , Cell Line , Fibroblasts/virology , Humans , Mice , Microscopy, Confocal , Molecular Sequence Data , Moloney murine leukemia virus/metabolism , Mutagenesis , Protein Structure, Tertiary , Receptors, Virus/metabolism , Virus ReplicationABSTRACT
Many aspects of epigenetic phenomena have been elucidated via studies of transposable elements. An active transposable element frequently loses its ability to mobilize and goes into an inactive state during development. In this study, we describe the cyclic activity of a maize transposable element dissociation (Ds) in rice. In rice genome, Ds undergoes the spontaneous loss of mobility. However, an inactive state of Ds can be changed into an active state during tissue culture. The recovery of mobility accompanies not only changes in the methylation patterns of the terminal region of Ds, but also alteration in the steady state level of the activator (Ac) mRNA that is expressed by a constitutive CaMV 35S promoter. Furthermore, the Ds-reactivation process is not random, but stage-specific during plantlet regeneration. Our findings have expanded previous observations on Ac reactivation in the tissue culture of maize.