| macrophage culture: influence of species-specific incubation temperature. | cultured mammalian cells are traditionally maintained at 37 degrees c, despite the fact that core body temperatures differ considerably among mammals. considering the body temperature of the adult pig, comparison was made of porcine macrophage cultures maintained at 37 degrees c and 39.2 degrees c. examination of the cells showed that granularity was higher in macrophages maintained at 39.2 degrees c, although no differences in cell size were observed. the density of mhc class i and ii expressio ... | 1998 | 9692868 |
| detection of african swine fever virus in infected pig tissues by immunocytochemistry and in sity hybridisation. | the techniques for determining cellular sites of establishment and persistence of african swine fever virus (asfv) were established in susceptible domestic pigs and the resistant african reservoir hosts, the warthog and bushpig. detection, both in vitro and in vivo, was achieved by in situ hybridisation and immunocytochemistry, focusing principally on specific probes for vp73, a major capsid protein. hybridisation of radio-labelled probes for dna and rna was relatively insensitive and time consu ... | 1998 | 9694328 |
| migration of mitochondria to viral assembly sites in african swine fever virus-infected cells. | an examination by electron microscopy of the viral assembly sites in vero cells infected with african swine fever virus showed the presence of large clusters of mitochondria located in their proximity. these clusters surround viral factories that contain assembling particles but not factories where only precursor membranes are seen. immunofluorescence microscopy revealed that these accumulations of mitochondria are originated by a massive migration of the organelle to the virus assembly sites. v ... | 1998 | 9696857 |
| cholesterol affects african swine fever virus infection. | african swine fever virus (asfv) enters cells by receptor mediated endocytosis and requires a fusion event between the viral envelope and the limiting membrane of the endosome at low ph. in order to investigate the role of cholesterol in the early stages of asfv infection, we have studied the effect of the removal of cell and viral membrane cholesterol by cholesterol oxidase treatment of cells and virions, as well as the effect of some inhibitors of cholesterol synthesis on the infectious pathwa ... | 1998 | 9714715 |
| serological and immunohistochemical study of african swine fever in wild boar in spain. | a serological and immunohistochemical study of african swine fever was carried out in wild boar killed in seven municipalities in the north of the province of córdoba during two hunting seasons (1991-92 and 1992-93), when the area was affected by the disease. fourteen of 147 wild boar analysed by elisa and immunoblotting had antibodies to african swine fever virus. the immunohistochemical study revealed that four cases (two seropositive and two seronegative) showed immunoreactivity to the anti-v ... | 1998 | 9725185 |
| macrophage cytoplasmic vesicle ph gradients and vacuolar h+-atpase activities relative to virus infection. | a number of viruses replicate in macrophages, some having an obligate requirement for a macrophage host. this raised the question concerning the role of the macrophage endosomal/lysosomal compartment during such infections. both lysosomotropic weak bases, amantadine and chloroquine, which interfere with endosomal/lysosomal ph gradients, and the macrolide antibiotic bafilomycin a1, which interferes with vacuolar h+-atpase, inhibited african swine fever (asf) virus replication in porcine macrophag ... | 1998 | 9738656 |
| intracellular virus dna distribution and the acquisition of the nucleoprotein core during african swine fever virus particle assembly: ultrastructural in situ hybridisation and dnase-gold labelling. | african swine fever virus (asfv) is a large complex icosahedral double-stranded dna virus that replicates in the cytoplasm of susceptible cells. assembly of new virus particles occurs within the perinuclear viroplasm bodies known as virus factories. two types of virus particle are routinely observed: "fulls," which are particles with an electron-dense dna-containing nucleoid, and "empties," which consist of the virus protein and membrane icosahedral shell but are without the incorporation of the ... | 1998 | 9740789 |
| african swine fever virus is enveloped by a two-membraned collapsed cisterna derived from the endoplasmic reticulum. | during the cytoplasmic maturation of african swine fever virus (asfv) within the viral factories, the dna-containing core becomes wrapped by two shells, an inner lipid envelope and an outer icosahedral capsid. we have previously shown that the inner envelope is derived from precursor membrane-like structures on which the capsid layer is progressively assembled. in the present work, we analyzed the origin of these viral membranes and the mechanism of envelopment of asfv. electron microscopy studi ... | 1998 | 9765444 |
| african swine fever virus nl gene is not required for virus virulence. | previously, we described a highly conserved nonessential african swine fever virus (asfv) right variable region gene, nl. deletion of nl from the european pathogenic isolate e70 resulted in almost complete attenuation of the virus in domestic swine. to study gene function further, nl gene deletion mutants were constructed from two pathogenic african asfv isolates, malawi lil-20/1 (mal) and pretoriuskop/96/4 (pr4). unexpectedly, both mal (mal-deltanl) and pr4 (pr4deltanl) null mutants remained hi ... | 1998 | 9780062 |
| functionality and cell anchorage dependence of the african swine fever virus gene a179l, a viral bcl-2 homolog, in insect cells. | the african swine fever virus gene a179l has been shown to be a functional member of the ced9/bcl-2 family of apoptosis inhibitors in mammalian cell lines. in this work we have expressed the a179l gene product (p21) under the control of the baculovirus polyhedrin promoter using a baculovirus system. expression of the a179l gene neither altered the baculovirus replication phenotype nor delayed the shutoff of cellular protein synthesis, but it extended the survival of the infected insect cells to ... | 1998 | 9811766 |
| the african swine fever virus thymidine kinase gene is required for efficient replication in swine macrophages and for virulence in swine. | african swine fever virus (asfv) replicates in the cytoplasm of infected cells and contains genes encoding a number of enzymes needed for dna synthesis, including a thymidine kinase (tk) gene. recombinant tk gene deletion viruses were produced by using two highly pathogenic isolates of asfv through homologous recombination with an asfv p72 promoter-beta-glucuronidase indicator cassette (p72gus) flanked by asfv sequences targeting the tk region. attempts to isolate double-crossover tk gene deleti ... | 1998 | 9811782 |
| identification of a 25-aminoacid sequence from the major african swine fever virus structural protein vp72 recognised by porcine cytotoxic t lymphocytes using a lipoprotein based expression system. | identification of african swine fever virus (asfv) proteins recognised by cytotoxic t lymphocytes (ctl) from swine surviving asfv/nh/p68 infection was assessed using expression vectors based on the pseudomonas aeruginosa outer membrane lipoprotein i gene (opri). viral antigens expressed as fusion lipoproteins were shown to be taken efficiently by porcine blood-derived macrophages incubated with outer membrane protein preparations from transformed e. coli. to assess recognition by ctl the fusion ... | 1998 | 9820580 |
| characterization of immobilization methods for african swine fever virus protein and antibodies with a piezoelectric immunosensor. | a direct piezoelectric flow injection analysis immunoassay for the detection of african swine fever virus and antibodies is presented. the peptide-specific monoclonal antibody 18bg3 and the virus protein 73 were used for detection with a quartz crystal microbalance. accumulation of the analyte on the surface of this mass-sensitive biosensor resulted in a shift of the resonant frequency. highly selective receptor layers were applied on the sensing electrode of the quartz crystal for detection of ... | 1998 | 9883562 |
| african swine fever virus infection induces tumor necrosis factor alpha production: implications in pathogenesis. | we have analyzed the production of tumor necrosis factor alpha (tnf-alpha) induced by in vitro infection with african swine fever (asf) virus (asfv) and the systemic and local release of this inflammatory cytokine upon in vivo infection. an early increase in tnf-alpha mrna expression was detected in asfv-infected alveolar macrophages, and high levels of tnf-alpha protein were detected by elisa in culture supernatants from these cells. when animals were experimentally infected with a virulent iso ... | 1999 | 9971800 |
| a lipid modified ubiquitin is packaged into particles of several enveloped viruses. | an anti-ubiquitin cross-reactive protein which migrates more slowly (6.5 kda) by sds-page than ubiquitin was identified in african swine fever virus particles. this protein was extracted into the detergent phase in triton x-114 phase separations, showing that it is hydrophobic, and was radiolabelled with both [3h]palmitic acid and [32p]orthophosphate. this indicates that the protein has a similar structure to the membrane associated phosphatidyl ubiquitin described in baculovirus particles. a si ... | 1999 | 10037162 |
| nuclear and nucleolar localization of an african swine fever virus protein, i14l, that is similar to the herpes simplex virus-encoded virulence factor icp34.5. | pcr analysis of the genomes of 18 different african swine fever virus (asfv) isolates showed that the i14l open reading frame (orf) was present as either a long form or short form in all of the isolates. sequencing of the orf from eight isolates confirmed that both forms of the orf were well conserved. antisera raised against the i14l protein identified the long form of the protein as a 21 kda protein expressed late during asfv infection. immunofluorescent analysis of transiently expressed haema ... | 1999 | 10091989 |
| modulation of monocytic cell activity and virus susceptibility during differentiation into macrophages. | a major component of innate immune responses relies on monocytes and macrophages, virus infection of which will pose a particular problem for immunological defense. consequently, the monocytic cell differentiation pathway was analyzed in terms of cellular modulations therein and their relation to monocytotropic virus infection. differentiation was characterized by down-regulation of cd14, mhc ags, the monocytic swc1 marker, and p53; concomitant up-regulation of the swc9 macrophage marker, a puta ... | 1999 | 10201916 |
| the biological effects induced in mice by p36, a proteinaceous factor of virulence produced by african swine fever virus, are mediated by interleukin-4 and also to a lesser extent by interleukin-10. | we have previously presented indirect evidence that both specific immunosuppression and lymphocyte mitogenicity induced in mice by p36, a proteinaceous factor of virulence produced by porcine monocytes infected by african swine fever virus, were consistent with a th2-driven response. here we show: (1) interleukin-4 (il-4) and interleukin-10 (il-10) mrna expression in the spleen and thymus of c57bl/6 mice were displayed early after p36 inoculation. the expression of thymic il-10 mrna occurred, ho ... | 1999 | 10233720 |
| replication of african swine fever virus dna in infected cells. | we have examined the ultrastructural localization of african swine fever virus dna in thin-sections of infected cells by in situ hybridization and autoradiography. virus-specific dna sequences were found in the nucleus of infected vero cells at early times in the synthesis of the viral dna, forming dense foci localized in proximity to the nuclear membrane. at later times, the viral dna was found exclusively in the cytoplasm. electron microscopic autoradiography of african swine fever virus-infec ... | 1999 | 10329562 |
| the african swine fever virus prenyltransferase is an integral membrane trans-geranylgeranyl-diphosphate synthase. | in a previous study, it was shown that the protein encoded by the gene b318l of african swine fever virus (asfv) is a trans-prenyltransferase that catalyzes in vitro the condensation of farnesyl diphosphate and isopentenyl diphosphate to synthesize geranylgeranyl diphosphate and longer chain prenyl diphosphates (alejo, a., yáñez, r. j., rodríguez, j. m., viñuela, e., and salas, m. l. (1997) j. biol. chem. 272, 9417-9423). to investigate the in vivo function of the viral enzyme, we have determine ... | 1999 | 10364254 |
| african swine fever virus: a b cell-mitogenic virus in vivo and in vitro. | the two major characteristics of pathogenesis in african swine fever virus (asfv) infections of domestic pigs are massive b-cell apoptosis and haemorrhage. the effects of asfv on porcine b cells have therefore been systematically examined in vivo, by using virus-infected pigs and scid-beige mice reconstituted with porcine bone marrow, and in vitro, by using porcine b-cell lines and b cells from normal and asfv-infected pigs. secretion of porcine ig was stimulated by asfv both in vivo and in bone ... | 1999 | 10374963 |
| laboratory-scale inactivation of african swine fever virus and swine vesicular disease virus in pig slurry. | two methods were evaluated for the inactivation of african swine fever (asv) and swine vesicular disease (svd) viruses in pig slurry: chemical treatment and heat treatment. the addition of naoh or ca(oh)2 at different concentration/time combinations at 4 degrees c and 22 degrees c was examined, as was virus stability at different temperature/time combinations. asf virus (asfv) was less resistant to both methods than svd virus (svdv). in slurry from one source, asfv was inactivated at 65 degrees ... | 1999 | 10432596 |
| design and construction of african swine fever virus chimeras incorporating foreign viral epitopes. | in the present work we have studied the feasibility of introducing foreign epitopes into the african swine fever virus (asfv) particle by genetic manipulation of the virus. for this purpose, we developed specific transfer vectors containing the gene encoding for the highly antigenic structural asfv protein p54 in which foreign sequences were introduced. dna sequences encoding continuous linear epitopes, the antigenic site a from foot-and-mouth disease virus (fmdv) vp1 protein and the da3 antigen ... | 1999 | 10481737 |
| virus-specific cell receptors are necessary, but not sufficient, to confer cell susceptibility to african swine fever virus. | the entry of african swine fever (asf) virus into vero cells and swine macrophages is mediated by saturable binding sites located in the plasma membrane, which have been related, as in other virus-cell systems, to the sensitivity of the cell to the virus. in order to define this correlation, we have analyzed up to 16 cell lines derived from different species for their sensitivity to virus infection, to determine the step in the virus infective cycle that was blocked in each resistant cell, the p ... | 1999 | 10481739 |
| african swine fever virus replication in the midgut epithelium is required for infection of ornithodoros ticks. | although the malawi lil20/1 (mal) strain of african swine fever virus (asfv) was isolated from ornithodoros sp. ticks, our attempts to experimentally infect ticks by feeding them this strain failed. ten different collections of ornithodorus porcinus porcinus ticks and one collection of o. porcinus domesticus ticks were orally exposed to a high titer of mal. at 3 weeks postinoculation (p.i.), <25% of the ticks contained detectable virus, with viral titers of <4 log(10) 50% hemadsorbing doses/ml. ... | 1999 | 10482612 |
| african swine fever virus dutpase is a highly specific enzyme required for efficient replication in swine macrophages. | the african swine fever virus (asfv) gene e165r, which is homologous to dutpases, has been characterized. a multiple alignment of dutpases showed the conservation in asfv dutpase of the motifs that define this protein family. a biochemical analysis of the purified recombinant enzyme showed that the virus dutpase is a trimeric, highly specific enzyme that requires a divalent cation for activity. the enzyme is most probably complexed with mg(2+), the preferred cation, and has an apparent k(m) for ... | 1999 | 10515998 |
| intermediate stages in monocyte-macrophage differentiation modulate phenotype and susceptibility to virus infection. | the kinetics of monocyte-macrophage differentiation was analysed using two swine workshop cluster (swc) cd molecules: swc1 and swc9. myeloid cells were selected by labelling for the common myeloid antigen, swc3. confirmation of macrophage identification used acid phosphatase and phagocytosis activities. during differentiation, swc1 was gradually lost. swc9 was absent on monocytes but up-regulated early. consequently, monocytes were swc1+ swc9- and macrophages were swc1- swc9+. an additional, int ... | 1999 | 10540219 |
| recovery and assay of african swine fever and swine vesicular disease viruses from pig slurry. | assaying samples for infectious virus is more difficult when the sample is toxic to cells used in the assay, e.g. with samples of infected pig slurry. various techniques were compared for the recovery of african swine fever virus (asfv) and swine vesicular disease virus (svdv) in pig slurry. extraction with freon led to 80-100% recovery of svdv added to pig slurry. the assay sensitivity enabled undiluted, centrifuged sample to be put directly onto monolayers of ib-rs2 cells, allowing a minimum d ... | 1999 | 10540248 |
| pilot scale thermal treatment of pig slurry for the inactivation of animal virus pathogens. | this paper describes a pilot scale treatment plant that has been designed and built for the thermal inactivation in pig slurry of two viruses that infect pigs--african swine fever virus (asfv) and swine vesicular disease virus (svdv). the plant treats pig slurry continuously at a rate of up to 100 litres/hour and functions by heating the slurry, maintaining at least 99.99% of the slurry at the required temperature for a minimum period of 5 minutes, and then recovering the heat to raise the tempe ... | 1999 | 10565423 |
| an african swine fever virus orf with similarity to c-type lectins is non-essential for growth in swine macrophages in vitro and for virus virulence in domestic swine. | an african swine fever virus (asfv) orf, 8cr, with similarity to the c-type lectin family of adhesion proteins has been described in the pathogenic isolate malawi lil-20/1. the similarity of 8cr to cellular and poxvirus genes associated with cell adhesion, cell recognition and virus infectivity suggested that 8cr may be of significance to asfv-host cell interactions. sequence analysis of the 8cr orf from additional pathogenic asfv isolates demonstrated conservation among isolates from both pig a ... | 1999 | 10573162 |
| in vitro inhibition of the replication of haemorrhagic septicaemia virus (vhsv) and african swine fever virus (asfv) by extracts from marine microalgae. | we have screened for in vitro inhibition of viral replication with extracts from the following marine microalgae: porphyridium cruentum, phaeodactylum tricornutum, tetraselmis suecica, chlorella autotrophica, dunaliella tertiolecta, dunaliella bardawil, isochrysis galbana, isochrysis galbana var tiso, ellipsoidon sp. and tetraselmis tetrathele. we have used as viral models two enveloped viruses of significant economic importance, the viral hemorrhagic septicemia virus (vhsv) of salmonid fish and ... | 1999 | 10588334 |
| an african swine fever virus erv1-alr homologue, 9gl, affects virion maturation and viral growth in macrophages and viral virulence in swine. | the african swine fever virus (asfv) genome contains a gene, 9gl, with similarity to yeast erv1 and alr genes. erv1 has been shown to function in oxidative phosphorylation and in cell growth, while alr has hepatotrophic activity. 9gl encodes a protein of 119 amino acids and was highly conserved at both nucleotide and amino acid levels among all asfv field isolates examined. monospecific rabbit polyclonal antibody produced to a glutathione s-transferase-9gl fusion protein specifically immunopreci ... | 2000 | 10627538 |
| regulation of calcineurin by growth cone calcium waves controls neurite extension. | growth cones generate spontaneous transient elevations of intracellular ca(2+) that regulate the rate of neurite outgrowth. here we report that these ca(2+) waves inhibit neurite extension via the ca(2+)-dependent phosphatase calcineurin (cn) in xenopus spinal neurons. pharmacological blockers of cn (cyclosporin a and deltamethrin) and peptide inhibitors of cn [the xenopus cn (xcn) autoinhibitory domain and african swine fever virus protein a238l] block the ca(2+)-dependent reduction of neurite ... | 2000 | 10627609 |
| african swine fever virus ep153r open reading frame encodes a glycoprotein involved in the hemadsorption of infected cells. | the open reading frame ep153r, located within the ecori e' fragment of the african swine fever (asf) virus genome, is predicted to encode a membrane protein of 153 amino acids that presents significant homology to the n-terminal region of several cd44 molecules. ep153r contains multiple putative sites for n-glycosylation, phosphorylation, and myristoylation, a central transmembrane region, a c-type animal lectin-like domain, and a cell attachment sequence. transcription of ep153r takes place at ... | 2000 | 10639320 |
| characterization of the african swine fever virus protein p49: a new late structural polypeptide. | the open reading frame b438l, located within the ecori b fragment of the african swine fever virus genome, is predicted to encode a protein of 438 amino acids with a molecular mass of 49.3 kda. it presents a cell attachment rgd (arg-gly-asp) motif but no other significant similarity to protein sequences in databases. northern blot and primer extension analysis showed that b438l is transcribed only at late times during virus infection. the b438l gene product has been expressed in escherichia coli ... | 2000 | 10640542 |
| biochemical requirements of virus wrapping by the endoplasmic reticulum: involvement of atp and endoplasmic reticulum calcium store during envelopment of african swine fever virus. | enwrapment by membrane cisternae has emerged recently as a mechanism of envelopment for large enveloped dna viruses, such as herpesviruses, poxviruses, and african swine fever (asf) virus. for both asf virus and the poxviruses, wrapping is a multistage process initiated by the recruitment of capsid proteins onto membrane cisternae of the endoplasmic reticulum (er) or associated er-golgi intermediate membrane compartments. capsid assembly induces progressive bending of membrane cisternae into the ... | 2000 | 10666244 |
| effects of chlorine, iodine, and quaternary ammonium compound disinfectants on several exotic disease viruses. | the effects of three representative disinfectants, chlorine (sodium hypochlorite), iodine (potassium tetraglicine triiodide), and quaternary ammonium compound (didecyldimethylammonium chloride), on several exotic disease viruses were examined. the viruses used were four enveloped viruses (vesicular stomatitis virus, african swine fever virus, equine viral arteritis virus, and porcine reproductive and respiratory syndrome virus) and two non-enveloped viruses (swine vesicular disease virus (svdv) ... | 2000 | 10676896 |
| an arid family protein binds to the african swine fever virus encoded ubiquitin conjugating enzyme, ubcv1. | the nh(2)-terminal end of a protein, named smcp, which contains an arid (a/t rich interaction domain) dna binding domain and is similar to the mammalian smcy/smcx proteins and retinoblastoma binding protein 2, was shown to bind the african swine fever virus encoded ubiquitin conjugating enzyme (ubcv1) using the yeast two hybrid system and in in vitro binding assays. antisera raised against the smcp protein were used to show that the protein is present in the cell nucleus. immunofluorescence show ... | 2000 | 10760505 |
| an outbreak of african swine fever in nigeria: virus isolation and molecular characterization of the vp72 gene of a first isolate from west africa. | the isolation of 98/asf/ng, a strain of african swine fever virus (asfv) associated with a 1998 epizootic in nigeria, is reported. this first isolate of the virus from west africa was identified through a successful polymerase chain reaction (pcr) amplification and sequencing of a 280 base pair (bp) fragment of the major capsid protein (vp72) gene. further amplification and sequence analysis of a 1.9 kilobase pair (kbp) fragment encompassing the complete vp72 gene showed that the isolate has a 9 ... | 2000 | 10872875 |
| structure of african swine fever virus late promoters: requirement of a tata sequence at the initiation region. | a number of mutations, including deletions, linker scan substitutions, and point mutations, were performed in the promoter of the late african swine fever virus (asfv) gene coding for the capsid protein p72. the consequences of the mutations in terms of promoter activity were analyzed by luciferase assays using plasmids transfected into infected cells. the results showed that the promoter function is contained between nucleotides -36 and +5 relative to the transcription initiation site. moreover ... | 2000 | 10933729 |
| mechanism of inactivation of nf-kappa b by a viral homologue of i kappa b alpha. signal-induced release of i kappa b alpha results in binding of the viral homologue to nf-kappa b. | activation of the nuclear factor kappa b plays a key role in viral pathogenesis, resulting in inflammation and modulation of the immune response. we have previously shown that a238l, an open reading frame from african swine fever virus (asfv), encoding a protein with 40% homology to porcine i kappa b alpha exerts a potent anti-inflammatory effect in host macrophages, where it down-regulates nf-kappa b-dependent gene transcription and proinflammatory cytokine production. this paper reveals the me ... | 2000 | 10934190 |
| the cellular immune recognition of proteins expressed by an african swine fever virus random genomic library. | the cellular immune recognition of peptides expressed by an african swine fever virus (asfv) random genomic library has been studied. dna from the malawi (lil20/1) asfv isolate was randomly sheared by sonication, cloned into a plasmid vector downstream of a bacteriophage t7 promoter, and 72 recombinant plasmids were arbitrarily selected. these plasmids were transiently expressed following transfection into major histocompatibility complex (mhc) class i(+) class ii(-) matched pig skin cells, whic ... | 2000 | 10986387 |
| serodiagnosis of african swine fever using the recombinant protein p30 expressed in insect larvae. | african swine fever (asf) has a substantial economic impact in many african developing countries and its eradication is based only on an efficient diagnosis program because of the absence of an available vaccine. previous data suggested the convenience of using the highly antigenic virus protein p30 as elisa antigen for serological diagnosis of this disease. a simple and efficient method is described for producing the recombinant protein p30 from asf virus in trichoplusia ni larvae (cabbage loop ... | 2000 | 10996646 |
| african swine fever virus protein a238l interacts with the cellular phosphatase calcineurin via a binding domain similar to that of nfat. | the african swine fever virus protein a238l inhibits activation of nfat transcription factor by binding calcineurin and inhibiting its phosphatase activity. nfat controls the expression of many immunomodulatory proteins. here we describe a 14-amino-acid region of a238l that is needed and sufficient for binding to calcineurin. by introducing mutations within this region, we have identified a motif (pxixitxc/s) required for a238l binding to calcineurin; a similar motif is found in nfat proteins. p ... | 2000 | 11000210 |
| bacterial lipoprotein based expression vectors as tools for the characterisation of african swine fever virus (asfv) antigens. | african swine fever virus (asfv) is the causative agent of an important pig disease for which protective mechanisms are still poorly understood. the present work was aimed at the characterisation of asfv antigens using previously reported vectors that allow their expression as fusion proteins with the bacterial lipoprotein opri. several recombinant clones induced sla-restricted, asfv-specific lymphoproliferation and one (a2) was demonstrated to stimulate asfv-specific ctl activity in vitro, in o ... | 2000 | 11003474 |
| iridovirus homologues of cellular genes--implications for the molecular evolution of large dna viruses. | iridoviruses belong to the group of large cytoplasmic deoxyriboviruses and infect either insects or vertebrates. in analogy to other large dna viruses of eucaryotes it was found that iridoviruses encode a number of cellular protein homologues. the majority of these proteins represent orthologues of cellular enzymes involved in transcription, replication, and nucleotide metabolism. others may have the potential to interfere with cell cycle regulation or immune defence mechanisms of the host. this ... | 2000 | 11022791 |
| eladio viñuela (1937-1999), the molecular biology pioneer in spain. | | 1999 | 11023347 |
| african swine fever virus protease, a new viral member of the sumo-1-specific protease family. | african swine fever virus (asfv) is a complex dna virus that employs polyprotein processing at gly-gly-xaa sites as a strategy to produce several major core components of the viral particle. the virus gene s273r encodes a 31-kda protein that contains a "core domain" with the conserved catalytic residues characteristic of sumo-1-specific proteases and the adenovirus protease. using a cos cell expression system, it was found that protein ps273r is capable of cleaving the viral polyproteins pp62 an ... | 2001 | 11031264 |
| effects of infection of the tick ornithodoros moubata with african swine fever virus. | the effects of infection with african swine fever virus (asfv) on adult and nymphal ornithodoros moubata murray (ixodoidea, argasidae) ticks were examined. three groups of ticks were used, an uninfected control group, one group infected with the vic t90/1 isolate of asfv and another group infected with the liv 13/33 isolate of asfv. infection with asfv did not affect the oviposition rates of infected ticks when compared with uninfected ticks. there was no difference between infected and uninfect ... | 2000 | 11129698 |
| identification and characterization of a spliced c-type lectin-like gene encoded by rat cytomegalovirus. | the english isolate of rat cytomegalovirus (rcmv) encodes a 20-kda protein with a c-type lectin-like domain that is expressed in the delayed-early and late phases of the viral replication cycle. genomic sequence analysis of the restriction fragment kpnr of rcmv revealed significant homology to several c-type lectin-containing molecules implicated in natural killer (nk) and t-cell interactions, as well as genes from four poxviruses and african swine fever virus. the gene is spliced into five exon ... | 2001 | 11134273 |
| rna triphosphatase component of the mrna capping apparatus of paramecium bursaria chlorella virus 1. | paramecium bursaria chlorella virus 1 (pbcv-1) elicits a lytic infection of its unicellular green alga host. the 330-kbp viral genome has been sequenced, yet little is known about how viral mrnas are synthesized and processed. pbcv-1 encodes its own mrna guanylyltransferase, which catalyzes the addition of gmp to the 5' diphosphate end of rna to form a gpppn cap structure. here we report that pbcv-1 encodes a separate rna triphosphatase (rtp) that catalyzes the initial step in cap synthesis: hyd ... | 2001 | 11160672 |
| the non-haemadsorbing african swine fever virus isolate asfv/nh/p68 provides a model for defining the protective anti-virus immune response. | african swine fever virus asfv/nh/p68 is a naturally occurring, non-haemadsorbing and non-fatal isolate. longitudinal clinical and immunological studies on 31 pigs inoculated oronasally or intramuscularly with this isolate defined two discrete groups of animals: those developing asf chronic type lesions and those remaining asymptomatic. animals developing lesions had viraemia and fever late after infection, nk activity levels close to that of control animals and high levels of anti-asfv specific ... | 2001 | 11172092 |
| african swine fever virus iap homologue inhibits caspase activation and promotes cell survival in mammalian cells. | african swine fever virus (asfv) a224l is a member of the inhibitor of apoptosis protein (iap) family. we have investigated the antiapoptotic function of the viral iap both in stably transfected cells and in asfv-infected cells. a224l was able to substantially inhibit caspase activity and cell death induced by treatment with tumor necrosis factor alpha and cycloheximide or staurosporine when overexpressed in vero cells by gene transfection. we have also observed that asfv infection induces caspa ... | 2001 | 11222676 |
| african swine fever virus multigene family 360 and 530 genes are novel macrophage host range determinants. | pathogenic african swine fever virus (asfv) isolates primarily target cells of the mononuclear-phagocytic system in infected swine and replicate efficiently in primary macrophage cell cultures in vitro. asfvs can, however, be adapted to grow in monkey cell lines. characterization of two cell culture-adapted viruses, ms16 and ba71v, revealed that neither virus replicated in macrophage cell cultures. cell viability experiments and ultrastructural analysis showed that infection with these viruses r ... | 2001 | 11238833 |
| two distinct action mechanisms of immunophilin-ligand complexes for the blockade of t-cell activation. | the immunosuppressive effects of cyclosporin a (csa) and fk506 are mediated through binding to immunophilins. here we show that fk506-fkbp complex suppresses the activation of jnk and p38 pathways at a level upstream of mitogen-activated protein kinase (mapk) kinase kinase (mapkk-k) besides the calcineurin-nfat pathway. a238l, a viral gene product that binds to immunophilin, also blocks activation of both pathways. in contrast, direct inhibitors of calcineurin, cabin 1 and fr901725, suppress the ... | 2000 | 11258483 |
| aggresomes resemble sites specialized for virus assembly. | the large cytoplasmic dna viruses such as poxviruses, iridoviruses, and african swine fever virus (asfv) assemble in discrete perinuclear foci called viral factories. factories exclude host proteins, suggesting that they are novel subcellular structures induced by viruses. novel perinuclear structures, called aggresomes are also formed by cells in response to misfolded protein (johnston, j.a., c.l. ward, and r.r. kopito. 1998. j. cell biol. 143:1883--1898; garcía-mata, r., z. bebök, e.j. sorsche ... | 2001 | 11331297 |
| transovarial transmission of african swine fever virus in the argasid tick ornithodoros moubata. | the aim of this study was to determine filial infection prevalence of experimentally infected colony ornithodoros moubata walton (ixodoidea: argasidae) ticks for african swine fever virus (asfv). three groups of ticks were used: an uninfected control group, one group orally infected with the vic t90/1 isolate and another group orally infected with the liv 13/33 isolate of asfv. the results show that filial infection prevalences were not constant but were highly variable between egg batches from ... | 2001 | 11434547 |
| african swine fever virus structural protein pe120r is essential for virus transport from assembly sites to plasma membrane but not for infectivity. | this report examines the role of african swine fever virus (asfv) structural protein pe120r in virus replication. immunoelectron microscopy revealed that protein pe120r localizes at the surface of the intracellular virions. consistent with this, coimmunoprecipitation assays showed that protein pe120r binds to the major capsid protein p72. moreover, it was found that, in cells infected with an asfv recombinant that inducibly expresses protein p72, the incorporation of pe120r into the virus partic ... | 2001 | 11435554 |
| [african swine fever virus: achievements over the last decade of the 20th century]. | complete nucleotide sequence of african swine fever (asf) virus genome was determined in 1993-1999. deletion mutants with low virulence for pigs were obtained. genes of structural (p72, p54, p12, cleavage products pp220 and pp60, hemagglutinin) and nonstructural (p32) proteins were mapped. the significance of different proteins in virus adsorption and resistance to challenge was elucidated, their location in infected cell and virion was determined. lipid composition of the virus was studied. a p ... | 2001 | 11449798 |
| a dna polymerase with specificity for five base pairs. | | 2001 | 11456786 |
| a virally encoded chaperone specialized for folding of the major capsid protein of african swine fever virus. | it is generally believed that cellular chaperones facilitate the folding of virus capsid proteins, or that capsid proteins fold spontaneously. here we show that p73, the major capsid protein of african swine fever virus (asfv) failed to fold and aggregated when expressed alone in cells. this demonstrated that cellular chaperones were unable to aid the folding of p73 and suggested that asfv may encode a chaperone. an 80-kda protein encoded by asfv, termed the capsid-associated protein (cap) 80, b ... | 2001 | 11461995 |
| isolation of a non-haemadsorbing, non-cytopathic strain of african swine fever virus in madagascar. | african swine fever (asf) suspected clinically in madagascar (1998-9) was confirmed by polymerase chain reaction (pcr) and nucleotide sequencing, following virus isolation. no haemadsorption or cytopathic effect could be detected following leukocyte inoculation, but viral growth in cells was confirmed by pcr. detection of asf virus genome was carried out by amplification of a highly conserved region coding for the p72 protein. nucleotide sequencing of the amplicon revealed 99.2% nucleotide ident ... | 2001 | 11467803 |
| novel virulence and host range genes of african swine fever virus. | current work is beginning to reveal the complex mechanisms by which african swine fever virus interacts with its swine and tick hosts. this work includes the identification of novel viral genes that mediate virulence and host range, and influence important cellular regulatory pathways. | 2001 | 11495811 |
| ornithodoros porcinus ticks, bushpigs, and african swine fever in madagascar. | african swine fever (asf) has recently made its appearance in madagascar. ticks of the ornithodoros moubata group, considered to be o. porcinus walton, 1962 were formerly known to occur in western madagascar, but seem to have disappeared from that region. however, three new sites where they occur were found in the humid and cool central highlands of anatananarivo province. these ticks are known to be efficient reservoirs and vectors of asf and constitute a considerable complication to the contro ... | 2001 | 11523921 |
| lipopolysaccharide and phorbol 12-myristate 13-acetate both impair monocyte differentiation, relating cellular function to virus susceptibility. | both lipopolysaccharide (lps) and phorbol 12-myristate 13-acetate (pma) impeded monocyte to macrophage differentiation with respect to typical phenotypic modulation and certain phagocyte-related processes. the down-regulation of the porcine monocyte marker swc1, and up-regulation of the swc9 macrophage marker were retarded, but not inhibited, as was the differentiation-associated down-regulation of p53 and myeloperoxidase. despite this clear impairment of macrophage differentiation, not all cell ... | 2001 | 11529940 |
| african swine fever virus protein p54 interacts with the microtubular motor complex through direct binding to light-chain dynein. | dynein is a minus-end-directed microtubule-associated motor protein involved in cargo transport in the cytoplasm. african swine fever virus (asfv), a large dna virus, hijacks the microtubule motor complex cellular transport machinery during virus infection of the cell through direct binding of virus protein p54 to the light chain of cytoplasmic dynein (lc8). interaction of p54 and lc8 occurs both in vitro and in cells, and the two proteins colocalize at the microtubular organizing center during ... | 2001 | 11559815 |
| african swine fever virus infection of porcine aortic endothelial cells leads to inhibition of inflammatory responses, activation of the thrombotic state, and apoptosis. | african swine fever (asf) is an asymptomatic infection of warthogs and bushpigs, which has become an emergent disease of domestic pigs, characterized by hemorrhage, lymphopenia, and disseminated intravascular coagulation. it is caused by a large icosohedral double-stranded dna virus, african swine fever virus (asfv), with infection of macrophages well characterized in vitro and in vivo. this study shows that virulent isolates of asfv also infect primary cultures of porcine aortic endothelial cel ... | 2001 | 11581405 |
| dna polymerases lose their grip. | | 2001 | 11685231 |
| solution structure of a viral dna repair polymerase. | dna polymerase x (pol x) from the african swine fever virus (asfv) specifically binds intermediates in the single-nucleotide base-excision repair process, an activity indicative of repair function. in addition, pol x catalyzes dna polymerization with low nucleotide-insertion fidelity. the structural mechanisms by which dna polymerases confer high or low fidelity in dna polymerization remain to be elucidated. the three-dimensional structure of pol x has been determined. unlike other dna polymeras ... | 2001 | 11685238 |
| solution structure of a viral dna polymerase x and evidence for a mutagenic function. | the african swine fever virus dna polymerase x (asfv pol x or pol x), the smallest known nucleotide polymerase, has recently been reported to be an extremely low fidelity polymerase that may be involved in strategic mutagenesis of the viral genome. here we report the solution structure of pol x. the structure, unique within the realm of nucleotide polymerases, consists of only palm and fingers subdomains. despite the absence of a thumb subdomain, which is important for dna binding in other polym ... | 2001 | 11685239 |
| three-dimensional structural model analysis of the binding site of lithocholic acid, an inhibitor of dna polymerase beta and dna topoisomerase ii. | the molecular action of lithocholic acid (lca), a selective inhibitor of mammalian dna polymerase beta (pol beta), was investigated. we found that lca could also strongly inhibit the activity of human dna topoisomerase ii (topo ii). no other dna metabolic enzymes tested were affected by lca. therefore, lca should be classified as an inhibitor of both pol beta and topo ii. here, we report the molecular interaction of lca with pol beta and topo ii. by three-dimensional structural model analysis an ... | 2001 | 11686928 |
| the trans golgi network is lost from cells infected with african swine fever virus. | the cellular secretory pathway is important during the assembly and envelopment of viruses and also controls the transport of host proteins, such as cytokines and major histocompatibility proteins, that function during the elimination of viruses by the immune system. african swine fever virus (asfv) encodes at least 26 proteins with stretches of hydrophobic amino acids suggesting entry into the secretory pathway (r. j. yanez, j. m. rodriguez, m. l. nogal, l. yuste, c. enriquez, j. f. rodriguez, ... | 2001 | 11689656 |
| antigenic and immunogenic properties of a chimera of two immunodominant african swine fever virus proteins. | a chimera of the two immunodominant african swine fever (asf) virus proteins p54 and p30 was constructed by insertion of the gene cp204l into a not i restriction site of e183l gene. the resulting chimeric protein p54/30, expressed by a recombinant baculovirus in insect cells and in trichoplusia ni larvae, retained antigenic determinants present in both proteins and reacted in western blot with a collection of sera from inapparent asf virus carrier pigs. remarkably, pigs immunized with the chimer ... | 2001 | 11699955 |
| 1h, 15n, and 13c resonance assignments for a 20 kda dna polymerase from african swine fever virus. | | 2001 | 11727982 |
| the g5r (d250) gene of african swine fever virus encodes a nudix hydrolase that preferentially degrades diphosphoinositol polyphosphates. | the african swine fever virus (asfv) g5r gene encodes a protein containing a nudix hydrolase motif which in terms of sequence appears most closely related to the mammalian diadenosine tetraphosphate (ap4a) hydrolases. however, purified recombinant g5r protein (g5rp) showed a much wider range of nucleotide substrate specificity compared to eukaryotic ap4a hydrolases, having highest activity with gtp, followed by adenosine 5'-pentaphosphate (p5a) and dgtp. diadenosine and diguanosine nucleotides w ... | 2002 | 11773415 |
| pathogenesis of african swine fever virus in ornithodoros ticks. | african swine fever virus (asfv) is the only known dna arbovirus and the sole member of the family asfarviridae. it causes a lethal, hemorrhagic disease in domestic pigs. asfv is enzootic in sub-saharan africa and is maintained in a sylvatic cycle by infecting both wild members of the suidae (e.g. warthogs) and the argasid tick ornithodoros porcinus porcinus. the pathogenesis of asfv in o. porcinus porcinus ticks is characterized by a low infectious dose, lifelong infection, efficient transmissi ... | 2001 | 11831434 |
| analysis of the complete nucleotide sequence of african swine fever virus. | we present an analysis of the complete genome of african swine fever virus (asfv) strain ba71v, including 80 kbp of novel sequence and 90 kbp previously reported by several authors. the viral dna is 170,101 nucleotides long and contains 151 open reading frames. structural and/or functional information is available on 113 viral proteins. asfv encodes five multigene families, putative membrane and secreted proteins, and enzymes involved in nucleotide and nucleic acid metabolism (including dna repa ... | 1995 | 11831707 |
| repression of african swine fever virus polyprotein pp220-encoding gene leads to the assembly of icosahedral core-less particles. | african swine fever virus (asfv) polyprotein pp220, encoded by the cp2475l gene, is an n-myristoylated precursor polypeptide that, after proteolytic processing, gives rise to the major structural proteins p150, p37, p34, and p14. these proteins localize at the core shell, a matrix-like virus domain placed between the dna-containing nucleoid and the inner envelope. in this study, we have examined the role of polyprotein pp220 in virus morphogenesis by means of an asfv recombinant, v220i, containi ... | 2002 | 11861832 |
| sequences and replication of genomes of the archaeal rudiviruses sirv1 and sirv2: relationships to the archaeal lipothrixvirus sifv and some eukaryal viruses. | the double-stranded dna genomes of the viruses sirv1 and sirv2, which infect the extremely thermophilic archaeon sulfolobus and belong to the family rudiviridae, were sequenced. they are linear, covalently closed at the ends, and 32,312 and 35,502 bp long, respectively, with an a+t content of 75%. the genomes of sirv1 and sirv2 carry inverted terminal repeats of 2029 and 1628 bp, respectively, which contain multiple direct repeats. sirv1 and sirv2 genomes contain 45 and 54 orfs, respectively, of ... | 2001 | 11878892 |
| novel swine virulence determinant in the left variable region of the african swine fever virus genome. | previously we have shown that the african swine fever virus (asfv) nl gene deletion mutant e70deltanl is attenuated in pigs. our recent observations that nl gene deletion mutants of two additional pathogenic asfv isolates, malawi lil-20/1 and pr4, remained highly virulent in swine (100% mortality) suggested that these isolates encoded an additional virulence determinant(s) that was absent from e70. to map this putative virulence determinant, in vivo marker rescue experiments were performed by in ... | 2002 | 11884534 |
| african swine fever virus iap-like protein induces the activation of nuclear factor kappa b. | african swine fever virus (asfv) encodes a homologue of the inhibitor of apoptosis (iap) that promotes cell survival by controlling the activity of caspase-3. here we show that asfv iap is also able to activate the transcription factor nf-kappab. thus, transient transfection of the viral iap increases the activity of an nf-kappab reporter gene in a dose-responsive manner in jurkat cells. similarly, stably transfected cells expressing asfv iap have elevated basal levels of c-rel, an nf-kappab-dep ... | 2002 | 11907233 |
| african swine fever virus-induced polypeptides in porcine alveolar macrophages and in vero cells: two-dimensional gel analysis. | high-resolution two-dimensional electrophoresis followed by computer analysis has been used to study quantitatively the patterns of protein synthesis produced in porcine alveolar macrophages and in vero cells infected with african swine fever virus (asfv). initially, a protein database for each cell type was constructed. the porcine alveolar macrophage database includes 995 polypeptides (818 acidic, isoelectric focusing (ief) and 177 basic, nonequilibrium ph gradient electrophoresis (nephge)) wh ... | 2001 | 11922604 |
| electrochemical characterization of screen-printed carbonaceous electrodes for the determination of peroxidase activity in novel screen-printed flow-through modules. | a novel totally screen-printed flow-through cell for immunoanalysis is presented. it contained screen-printed carbonaceous electrodes, which allowed the determination of peroxidase activity through the electrochemical reduction of p-benzoquinone. as different electrode materials differ strongly in their electrochemical properties, electrodes resulting from various screen-printable carbonaceous pastes were characterized using the hydroquinone/ p-benzoquinone redox couple. for most of the electrod ... | 2002 | 11936093 |
| african swine fever: expression of interleukin-1 alpha and tumour necrosis factor-alpha by pulmonary intravascular macrophages. | to determine, in the acute form of african swine fever (asf), the relationship between the appearance of pulmonary oedema and viral replication and expression of cytokines by pulmonary intravascular macrophages (pims), 14 pigs were inoculated intramuscularly with asf virus (strain españa'70) and killed in pairs on days 1-7 post-inoculation. samples of lung were examined immunohistochemically and ultrastructurally. the immunohistochemical study was carried out with antibodies against interleukin- ... | 2002 | 11945008 |
| orf virus encodes a functional dutpase gene. | the present study is the first report on the functional activity of a parapoxvirus-encoded dutpase. the dutpase gene of the attenuated orf virus (orfv), strain d1701, was expressed as a bacterial thioredoxin fusion protein. in vitro assays showed that orfv dutpase was highly specific for dutp as substrate. the enzyme was active over a broad ph range (ph 6.0-9.0), with maximal enzymatic activity at ph 7.0 in the presence of mg(2+) cations. kinetic studies of the recombinant orfv dutpase revealed ... | 2002 | 11961258 |
| apoptosis induced in an early step of african swine fever virus entry into vero cells does not require virus replication. | permissive vero cells develop apoptosis, as characterized by dna fragmentation, caspases activation, cytosolic release of mitochondrial cytochrome c, and flow cytometric analysis of dna content, upon infection with african swine fever virus (asfv). to determine the step in virus replication that triggers apoptosis, we used uv-inactivated virus, inhibitors of protein and nucleic acid synthesis, and lysosomotropic drugs that block virus uncoating. asfv-induced apoptosis was accompanied by caspase- ... | 2002 | 12009879 |
| identification of the principal serological immunodeterminants of african swine fever virus by screening a virus cdna library with antibody. | protective immunity to african swine fever virus (asfv) may involve a combination of both serological and cellular mechanisms. this work is focused on the identification of the possible relevant serological immunodeterminants of immunity. thus, 14 serological immunodeterminants of asfv have been characterized by exhaustive screening of a representative lambda phage cdna expression library of the tissue culture-adapted ba71v strain of asfv. the library was constructed using rna extracted from ver ... | 2002 | 12029148 |
| threat of foreign arthropod-borne pathogens to livestock in the united states. | there are many exotic animal pathogens throughout the world that, if introduced into the united states. could have a significant detrimental impact on the health of livestock, agricultural economy, the environment, and public health. many of these pathogens are arthropod-borne and potential vectors are readily available in the united states. a number of these arthropod-borne pathogens are discussed here as examples that illustrate the potential risk and the consequences of inadvertent introducti ... | 2002 | 12061432 |
| continuous porcine cell lines developed from alveolar macrophages: partial characterization and virus susceptibility. | porcine monomyeloid cell lines were established following transfection of primary porcine alveolar macrophage cultures with plasmid psv3neo, carrying genes for neomycin resistance and sv40 large t antigen. the parental clone 3d4 exhibited a relatively rapid doubling time (25.5 h), high plating efficiency and mixed phenotype with respect to growth on a solid support. single cell cloning of the 3d4 parent resulted in establishment of several cell lines; three of them designated 3d4/2, 3d4/21 and 3 ... | 2002 | 12088830 |
| plaque assay for african swine fever virus on swine macrophages. | a plaque assay developed to detect the infection of african swine fever virus on swine macrophages is described. plaques were generated by all of the virus isolates tested. the method is suitable not only for virus titration but also for the selection of clones in protocols for isolation/purification of recombinant viruses. | 2002 | 12111419 |
| development of an internal control for the detection of the african swine fever virus by pcr. | for the detection of african swine fever virus (asfv) by polymerase chain reaction (pcr) in clinical samples, an internal control was constructed to identify false negative results in each reaction. the internal control was designed in such a way that the same primer pair was used to amplify the internal control and the target dna which were differentiated by size. the lower detection limit was reached at about 30 internal control dna copies and about 50 genomic asfv dna copies. the use of the i ... | 2002 | 12144776 |
| structure-based combinatorial protein engineering (scope). | presented here is the development a semi-rational protein engineering approach that uses information from protein structure coupled with established dna manipulation techniques to design and create multiple crossover libraries from non-homologous genes. the utility of structure-based combinatorial protein engineering (scope) was demonstrated by its application to two distantly related members of the x-family of dna polymerases: rat dna polymerase beta (pol beta) and african swine fever virus dna ... | 2002 | 12206782 |
| the african swine fever virus protein j4r binds to the alpha chain of nascent polypeptide-associated complex. | the african swine fever virus (asfv) j4r protein is expressed late during the virus replication cycle and is present in both the nucleus and the cytoplasm of infected cells. by using the yeast two-hybrid system, direct binding, and coprecipitation from cells, we showed that the j4r protein binds to the alpha chain of nascent polypeptide-associated complex (alpha nac). confocal microscopy indicated that a proportion of j4r and alpha nac interact in areas close to the plasma membrane, as well as t ... | 2002 | 12208975 |
| changes in macrophages in spleen and lymph nodes during acute african swine fever: expression of cytokines. | to gain further insight into the pathogenesis of african swine fever (asf), the cytokine expression by macrophages in spleen and lymph nodes were examined. twenty-one piglets were inoculated with the highly virulent isolate spain-70 of asf virus and killed in groups at 1-7 post-inoculation days (pid). an increase in the immunohistochemical detection of proinflammatory monokines in spleen and renal and gastrohepatic lymph nodes is reported, along with an increase in the serum levels of tnf-alpha ... | 2002 | 12406651 |
| african swine fever virus polyproteins pp220 and pp62 assemble into the core shell. | african swine fever virus (asfv), a complex enveloped dna virus, expresses two polyprotein precursors, pp220 and pp62, which after proteolytic processing give rise to several major components of the virus particle. we have analyzed the structural role of polyprotein pp62, the precursor form of mature products p35 and p15, in virus morphogenesis. densitometric analysis of one- and two-dimensional gels of purified virions showed that proteins p35 and p15, as well as the pp220-derived products, are ... | 2002 | 12438573 |
| development of a taqman pcr assay with internal amplification control for the detection of african swine fever virus. | a closed-tube polymerase chain reaction (pcr) was developed to allow the rapid detection of african swine fever virus (asfv) dna. this assay targets the vp72 gene of asfv and uses the 5'-nuclease assay (taqman) system to detect pcr amplicons, avoiding tube opening and potential cross-contamination of post-pcr products. an artificial mimic was engineered with the taqman probe site replaced by a larger irrelevant dna fragment allowing discrimination from asfv by using two-colour taqman probe repor ... | 2003 | 12445938 |
| membrane association facilitates the correct processing of pp220 during production of the major matrix proteins of african swine fever virus. | the african swine fever (asf) virus polyprotein pp220 is processed at gly-gly-x sites by a virally encoded sumo-like protease to produce matrix proteins p150, p37, p34, and p14. four gly-gly-x sites are used to produce the matrix proteins, but the polyprotein contains an additional 15 sites potentially recognized by the protease. this study shows that cleavage occurs at many, if not all, gly-gly-x sites, and at steady state, p150 and p34 are minor products of processing. significantly, only the ... | 2003 | 12525602 |
| dna polymerase x of african swine fever virus: insertion fidelity on gapped dna substrates and ap lyase activity support a role in base excision repair of viral dna. | dna polymerase x (pol x) from african swine fever virus (asfv) is the smallest naturally ocurring dna-directed dna polymerase (174 amino acid residues) described so far. previous biochemical analysis has shown that asfv pol x is a highly distributive, monomeric enzyme, lacking a proofreading 3'-5' exonuclease. also, asfv pol x binds intermediates of the single-nucleotide base excision repair (ber) process, and is able to efficiently repair single-nucleotide gapped dna. in this work, we perform a ... | 2003 | 12595253 |
| polyprotein processing protease of african swine fever virus: purification and biochemical characterization. | the purified recombinant african swine fever virus polyprotein processing protease cleaves the two gg-x sites in polyprotein pp62 with the same efficiency. cleavage at the site that is first recognized in vivo is not a requisite for cleavage at the second site, suggesting the existence of mechanisms that control the ordered processing of the polyprotein during infection. | 2003 | 12634404 |
| genotyping field strains of african swine fever virus by partial p72 gene characterisation. | a pcr-based sequencing method was developed which permits detection and characterization of african swine fever virus (asfv) variants within 5 and 48 h, respectively, of receipt of a clinical specimen. amplification of a 478 bp fragment corresponding to the c-terminal end of the p72 gene, confirms virus presence with genetic characterization being achieved by nucleotide sequence determination and phylogenetic analysis. the method was applied to 55 viruses including those representative of the ma ... | 2003 | 12664294 |