Publications

antiviral activity of uridine 5'-diphosphate glucose analogues against some enveloped viruses in cell culture.	twenty five analogues of uridine 5'-diphosphate glucose were screened against herpes simplex type 2, vaccinia virus, sindbis virus and african swine fever virus. after screening, the compound 5'-[[[[(2",3",4",6"-tetra-o-benzoyl-alpha-d- glucopyranosyl)oxi]carbonyl]amino]sulfonyl]uridine (2), the synthesis of which has been reported (camarasa et al., j. med. chem. 28, 40-46, 1985), was selected for further study. this compound showed in vitro activity against all viruses tested. the replication o ...	1987	2837144
mechanical transmission of capripox virus and african swine fever virus by stomoxys calcitrans.	stomoxys calcitrans can act as an efficient mechanical vector of capripox virus and african swine fever virus. capripox virus was transmitted to a susceptible goat by flies infected 24 hours previously and the virus survived in some flies for at least four days. african swine fever virus was transmitted to susceptible pigs by flies infected one hour and 24 hours previously and the virus survived in these flies for at least two days without apparent loss of titre.	1987	2820006
genome analysis of african swine fever virus isolated in italy in 1983.	an african swine fever virus (asfv) isolated in an 1983 outbreak of the disease in piemonte, italy, was related by restriction endonuclease analysis of the viral genome to asfv strains isolated in the dominican republic (1978), haiti (1981) and cameroon (1982).	1987	2821672
physical characterization of the genome of a cattle isolate of capripoxvirus.	hindiii, pstl, aval, and sali site maps have been determined for the genome of a cattle isolate of capripoxvirus, kc-1. the length of the genome was estimated, by summation of the lengths of individual hindiii fragments, to be 145.6 kb, and the genome was shown to possess terminally repeated regions 1.13-6.23 kb in length. the restriction site maps demonstrate that the genome of kc-1 does not possess a high degree of nucleotide sequence homology with the genomes of isolates of orthopoxvirus, par ...	1987	2821685
african swine fever virus dna: deletions and additions during adaptation to growth in monkey kidney cells.	restriction enzyme cleavage maps for the fragments produced by cla i, sal i and sma i have been constructed for african swine fever virus (asfv) dna grown in pig leukocytes (strain e70 l6) and after adaptation to growth in ms monkey kidney cells (strain e70ms14). the mapping data revealed that before adaptation to growth in ms cells, the size of the dna from asfv strain e70 l6 was l73 kbp and after adaptation it was only l56 kbp. the decrease in size was produced by deletions and additions mainl ...	1987	2827611
proteins specified by african swine fever virus: v. identification of immediate early, early and late proteins.	autoradiographic analysis of polypeptides separated by polyacrylamide gel electrophoresis revealed that, after infection with asfv, ms cells synthesized at least 44 new polypeptides, that could be classified as immediate early, early or late proteins. a new viral polypeptide (ip 78) was detected by treatment of cells with cycloheximide for 14 hours.	1987	3101652
detection of dna viruses by radioactive and non radioactive dna probes: application to african swine fever virus.	a molecular hybridization technique using radioactive and non radioactive dna probes, has been used to detect asfv dna immobilized on nitrocellulose paper. it is based on the use of plasmid prpel-2 as a hybridization probe. this plasmid contain the h-clai dna fragment (size 5.6 kbp) from the spain-70 strain of asfv. the sensitivity of detection using radioactive 32p-probes (specific activity about 2 x 10(8) cpm per microgram) was about 20 pg of viral dna. the 32p-prpel-2 dna probe can detect abo ...	1987	3101653
a hemolymph test for the detection of african swine fever virus in ornithodoros coriaceus (acari: argasidae).		1987	3295242
prospects for the use of embryos in the control of disease and the transport of genotypes.	transfer and low temperature storage of embryos are now proven techniques for a number of mammalian species. these techniques are useful in control of disease and in saving genotypes from infected animals. the place of embryos in the epidemiology of disease depends upon whether the causative organism can gain entry to the oocyte before or at fertilisation and on whether the young embryo can be invaded by organisms in the uterine environment. there is little evidence that important live-stock dis ...	1987	3297016
cytopathogenic effect of african swine fever virus for pig monocytes: characterization and use in microassay.	a microculture assay is described for the titration of african swine fever virus (asfv) using swine monocytes contained in mononuclear leucocyte (mnl) microcultures. titration endpoints were determined by observing cytopathogenic effects (cpe) of asfv infected monocytes with an inverted microscope at 40 x magnification. cpe was a late event following the detection of asfv antigens in monocytes by radioimmune assay, immunofluorescence and hemadsorption. it began with the detachment, enlargement a ...	1987	3307125
the host response to african swine fever virus.		1987	3310105
potential arthropod vectors of african swine fever virus in north america and the caribbean basin.	in an effort to identify arthropods that might serve as vectors and perhaps reservoirs of african swine fever virus (asfv) if it were to enter the u.s.a., the blood-sucking insect triatoma gerstaeckeri and four species of ticks of the genus ornithodoros were established in colonies capable of reproducing in numbers sufficient to enable thorough studies to be made of their asfv vector potentials. a nymphal stage of t. gerstaeckeri carried the virus for 41 days and retained it through one molt, bu ...	1987	3326244
moderately virulent african swine fever virus infection: blood cell changes and infective virus distribution among blood components.	blood samples of pigs infected with a moderately virulent african swine fever virus (asfv) isolate, obtained from the dominican republic (dr-ii), were monitored temporally for viremia, infective asfv association with major blood components, differential changes in blood cell composition, and plasma antibodies to asfv. after intranasal/oral virus inoculation, pigs underwent acute infection and illness that resolved. acute illness began on postinoculation day (pid) 4 and continued to pid 11, and p ...	1988	3358545
effect of inhibitors of the host cell rna polymerase ii on african swine fever virus multiplication.	the role of the host cell rna polymerase ii in african swine fever (asf) virus growth has been examined using inhibitors of this enzyme. the adenosine analog 5,6-dichloro-1-beta-d-ribofuranosylbenzimidazole (drb), an inhibitor of mrna precursor synthesis in mammalian cells, strongly inhibits the production of infectious progeny virus in vero cells, but does not significantly affect the synthesis of virus-specific macromolecules. on the other hand, virion assembly seems to proceed normally in the ...	1988	3363868
inhibition of african swine fever virus dna synthesis by (s)-9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine.	the acyclic nucleotide analogue (s)-9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine [(s)-hpmpa] is a potent and selective inhibitor of african swine fever virus (asfv) replication. using the dna-dna hybridization technique with plasmid prpel-2 as probe, we have shown that (s)-hpmpa exerts a specific, dose-dependent, inhibitory effect on viral dna synthesis. also, (s)-hpmpa inhibits the production of late viral proteins, especially ip-73, in asfv-infected ms and vero cells. when evaluated under th ...	1988	3395330
a model virus-cell system to study the persistence of african swine fever virus.	the persistence of african swine fever virus (asfv) on vero cells was induced by using 5-iodo-2'-deoxyuridine (idu). after the persistence was established, several cycles of decreasing virus production were observed with intervals in which no virus could be detected. these latency-like periods could last from 15 to 25 days. after three and a half months the cells appeared to be "cured" and no virus was detected during almost three years. these "cured" cells (vero-l) were more resistant to superi ...	1988	3401116
isolation of african swine fever virus from ticks of the ornithodoros moubata complex (ixodoidea: argasidae) collected within the african swine fever enzootic area of malawi.	ticks of the ornithodoros moubata complex were collected from domestic pig sties and dwelling houses, and from a warthog habitat, and tested for the presence of african swine fever (asf) virus. collections were made in 9 of the 24 districts of malawi, these being primarily the districts in which o. moubata is most numerous. asf virus was isolated from ticks collected in both domestic pig sties and houses in certain villages in mchinji district where asf outbreaks had recently occurred. mchinji d ...	1988	3402546
phosphorylation of african swine fever virus proteins in vitro and in vivo.	highly purified african swine fever virus contains a cyclic amp-independent protein kinase which phosphorylates endogenous virus proteins with a specific activity of about 0.45 pmol/microgram of virus protein. the major substrates for the virion protein kinase in vitro were the structural proteins p10 and p9. both proteins were phosphorylated preferentially at serine residues. a possible relationship between protein p10 phosphorylation and rna synthesis in vitro by the virion-associated rna poly ...	1988	3139081
effect of interferon-alpha, interferon-gamma and tumour necrosis factor on african swine fever virus replication in porcine monocytes and macrophages.	bovine interferon-alpha i1 (ifn-alpha i1) and porcine interferon-gamma (ifn-gamma) inhibited african swine fever virus replication in both porcine monocytes and alveolar macrophages. the most potent antiviral activity was observed with ifn-gamma-treated alveolar macrophages. the production of both a virulent (cc83) and a non-virulent (ba71) isolate of the virus was inhibited. bovine tumour necrosis factor alpha did not show antiviral activity in either monocytes or alveolar macrophages. rather, ...	1988	3143809
hblv is not asfv.		1988	3196489
genetic diversity of african swine fever virus isolates from soft ticks (ornithodoros moubata) inhabiting warthog burrows in zambia.	the genomes of african swine fever virus isolates collected from soft ticks (ornithodoros moubata) inhabiting warthog burrows in four areas of zambia were compared by restriction enzyme site mapping. isolates from different areas showed considerable diversity. the regions of genomes that differed between isolates were distributed throughout the virus genome, although some more conserved regions were identified, such as the right-hand third of the genome. the genomes of seven isolates from neighb ...	1988	3199101
association of african swine fever virus with the cytoskeleton.	the association of african swine fever virus (asfv) with the cytoskeleton was investigated. immunofluorescent studies of asfv infected cells with anti-asfv serum showed a temporal and spatial development of viral inclusions which moved from a peripheral to a perinuclear location and fused to give a single large perinuclear factory. the migration and fusion of viral inclusions was inhibited by colchicine suggesting a function for microtubules in assembly site organization not previously described ...	1988	3201825
a protein of molar mass 12 kda incorporates into the membrane of asf virus-infected cells.	an african swine fever virus-induced protein of molar mass 12 kda (p12) was studied in virus-infected vero cells using the monoclonal antibody 18b.b11. protein p12 is incorporated into the membrane of infected cells about 7 h post-infection and is not present in purified african swine fever virus particles. the synthesis of protein p12 is sensitive to cytosine arabinoside.	1988	3201826
the distribution of african swine fever virus isolated from ornithodoros moubata in zambia.	african swine fever (asf) has been reported in the eastern province of zambia since 1912 and is now considered to be enzootic there. a survey of the distribution of asf virus in zambia was carried out by virus isolation from ornithodoros moubata ticks collected from animal burrows in national parks and game management areas in northern, eastern, central and southern zambia. asf virus was isolated from ticks in all areas examined. the prevalence of infection in o. moubata was between 0.4% in sout ...	1988	3215286
mapping and sequence of the gene encoding protein p37, a major structural protein of african swine fever virus.	the gene encoding protein p37, one of the major structural proteins of african swine fever (asf) virus has been mapped and sequenced. protein p37 was obtained from purified virions and the first 27 amino acids from its nh2-terminal end were identified by automatic edman degradation. to map the gene encoding protein p37, a mixture of 20-mer deoxyoligonucleotides based upon a part of this amino acid sequence was hybridized to cloned asf virus restriction fragments. this allowed localization of the ...	1988	3245132
correlation between b-cell mitogenicity and immunosuppressor effects of a protein released by porcine monocytes infected with african swine fever virus.	virus-free supernatants of cultured swine monocytes infected by african swine fever virus (asfv) suppressed in vitro proliferation of porcine and human blood mononuclear cells in response to phytohemagglutinin and the in vivo primary immune response of c57bl/6 mice against sheep rbc. the supernatants were fractionated by discontinuous ion-exchange chromatography and subfractionated by double-step preparative isoelectric focusing. the pool of the most purified active subfractions (f5'ep-asfv) is ...	1988	3266831
double labeling immunohistological study of african swine fever virus-infected spleen and lymph nodes.	to identify cells in situ in which african swine fever (asf) virus is present, a double immunohistological labeling technique was used on sections of asf-infected spleen and lymph nodes. cells were identified by an indirect immunoalkaline phosphatase technique using monoclonal antibodies (moab) reactive against different leukocyte subsets. asf virus, detected by a direct immunoperoxidase method using swine immunoglobulin g (igg) anti-asf virus antigens, was not present in t helper or in t cytoto ...	1988	3293303
genetic stability of african swine fever virus grown in monkey kidney cells. brief report.	viral dna subpopulations were produced when the asfv was grown in monkey kidney ms cells. they were detected after 44 passages but not during the first 14 passages or in the unadapted asfv e 70 strain grown in pig leukocytes. different viral variants were isolated and their genomes were characterized. restriction enzyme site variations were detected in both terminal fragments, cla i-m and sal i-f, and in the internal fragments clal-o and sma i-h. these variations result in changes in the size of ...	1988	2829794
molecular cloning and restriction enzyme mapping of an african swine fever virus isolate from malawi.	dna prepared from a field isolate of african swine fever virus, which causes high mortality and severe disease in domestic pigs, was cloned in bacteriophage lambda and plasmid vectors. clones containing dna inserts overlapping with each other and together covering the complete genome, apart from short fragments close to the cross-linked termini of the genome, were obtained. a complete restriction enzyme site map of the genome for three enzymes was deduced.	1988	2839602
epitopic diversity of african swine fever virus.	african swine fever (asf) is caused by an icosahedral cytoplasmic, double stranded dna virus. in the acute form of the disease, pigs die from disseminated intravascular coagulation (dic) with extensive damage of the free and fixed macrophage systems and the reticular epithelial cells of the thymus; mortality is virtually 100%. in recent years, subacute and chronic forms of asf have become more prevalent in the field, especially in outbreaks occurring outside the continent of africa, and virus is ...	1988	2451366
detection of antibodies against african swine fever virus using infected monolayers and monoclonal antibodies.	three monoclonal antibodies, specific for porcine igg, igm and iga, were used to develop isotype-specific immunoperoxidase monolayer assays for the detection of antibodies against african swine fever virus. a mixture of anti-igm and anti-igg monoclonal antibodies was used in an assay designed for screening sera. this test was compared with a commercially available elisa by using experimental sera and field sera obtained after an outbreak of african swine fever on two farms in the netherlands in ...	1988	3046107
[the biochemistry of the african swine fever virus].		1988	3046133
detection of african swine fever virus antibodies by immunoblotting assay.	an immunoblotting assay has been adapted to detect antibodies against african swine fever virus. the electrophoretic transfer of proteins and the immunoreaction conditions were optimized, using 4 ma/cm2 of current intensity and 10 micrograms of soluble cytoplasmic antigen of infected cells per strip. filters of polyvinylidene difluoride showed the highest capacity for protein absorption, but nitrocellulose filters showed lower backgrounds. the specificity and the pattern of the proteins induced ...	1989	2914218
saturable binding sites mediate the entry of african swine fever virus into vero cells.	binding experiments of 3h-labeled african swine fever virus to susceptible vero cells have shown the presence of saturable binding sites for african swine fever virus on the plasma membrane. the scatchard analysis of the binding data at equilibrium indicates the existence of about 10(4) cellular receptor sites per cell with a dissociation constant (kd) of 70 pm. virus entry into vero cells is mediated by a saturable component, since tritiated african swine fever virus saturable binding and uptak ...	1989	2916331
african swine fever virus-induced proteins on the plasma membranes of infected cells.	the african swine fever virus-induced proteins on plasma membranes of infected cells have been studied by two different procedures, iodination and incubation of infected cells labeled with [35s]methionine with a specific antiserum, obtained from pigs immunized with a monkey stable cell-adapted african swine fever virus. the combined use of both procedures identified proteins ip56, ip51, ip35, ip34, ip31, ip30, ip25.5, ip23.5, ip16, ip15, ip14, and ip12 as viral antigens exposed on the surface of ...	1989	2916332
variable and constant regions in african swine fever virus dna.	an analysis of the sali restriction pattern of african swine fever virus dna showed that the sali recognition sites did not change after more than 100 virus passages in porcine macrophages. the virus strain ba71v, obtained from the virus isolate ba71 by adaptation to grow in vero cells, differed from the nonadapted virus in two deletions with a length of 2.5 and 7 kb located close to the dna ends. a restriction analysis of several virus clones obtained from a naturally infected pig revealed leng ...	1989	2464873
in vitro transcription by cytoplasmic extracts from cells infected with african swine fever virus.	a cell-free system for the study of transcription of african swine fever virus (asfv) mrna was developed from cytoplasmic extracts of infected cells permeabilized with lysolecithin. extracts prepared from infected cells early and late after infection incorporated [alpha-32p]utp into acid-insoluble material that was resistant to dnase and sensitive to rnase. the incorporation was inhibited by actinomycin d but not by alpha-amanitin. the presence of the nuclei was not required. in vitro transcript ...	1989	2596035
antibodies to bovine serum albumin in swine sera: implications for false-positive reactions in the serodiagnosis of african swine fever.	antibodies to bovine serum albumin were detected in swine sera by use of an immunoblotting technique. such sera had false-positive reactions, as determined by results of african swine fever virus serodiagnostic techniques when bovine serum albumin was a contaminant in the soluble cytoplasmic antigen obtained from infected cells cultured in the presence of bovine serum. the soluble cytoplasmic antigen obtained from cell cultures infected with african swine fever virus in the presence of porcine s ...	1989	2672914
experimental african swine fever: evidence of the virus in interstitial tissues of the kidney.		1989	2711573
infection of pigs with the cameroon isolate (cam/82) of african swine fever virus.	african swine fever (asf) was produced in eight pigs by exposure to donors infected with the cameroon/82 isolate of african swine fever virus. the primary clinical sign was pyrexia of more than 40 degrees c first observed 10 to 13 days post-exposure (dpe) in all pigs; other clinical signs were rarely observed. the most frequent post-mortem lesion was haemorrhage in the visceral lymph nodes. other lesions included excess fluid in the abdominal cavity and petechial haemorrhages in the kidneys. vir ...	1989	2715397
gly-gly-x, a novel consensus sequence for the proteolytic processing of viral and cellular proteins.	three african swine fever virus structural proteins of relative molecular weights 150,000, 37,000, and 34,000 (p150, p37, and p34) are derived from precursors with relative molecular weights 220,000, 60,000, and 39,000 (pp220, pp60, and pp39) by proteolytic cleavage after the second gly residue in the sequence gly-gly-ala/gly. a search of the national biomedical research foundation data bank revealed that several adenovirus proteins, ubiquitin, and an interferon-induced 15-kda protein are also d ...	1989	2722819
a study of african swine fever virus infected ticks (ornithodoros moubata) collected from three villages in the asf enzootic area of malawi following an outbreak of the disease in domestic pigs.	a detailed study was made in 1983-5 in three villages in mchinji district in the african swine fever (asf) enzootic area of malawi, following an outbreak of asf which affected all three villages. ticks of the ornithodoros moubata complex were collected from both pig sties and houses shortly after the outbreak, and approximately 24% contained asf virus. the proportion of ticks infected did not differ significantly in the three villages, or more surprisingly in different types of premises, and was ...	1989	2737257
the entry of african swine fever virus into vero cells.	the entry of african swine fever virus into vero cells has been investigated by both biochemical and morphological techniques. a quantitative electron microscopy analysis of the early steps of the infection has shown that african swine fever virus enters vero cells by a receptor-mediated endocytosis mechanism. the internalization of virus particles is a temperature- and energy-dependent process, since it did not take place at 4 degrees or in the presence of naf and 2,4-dinitrophenol. to determin ...	1989	2741349
clearance of african swine fever virus from infected tick (acari) colonies.	three laboratory colonies of the argasid tick onithodoros moubata porcinus van der merwe were started from collections made in 1983 at three different sites in zimbabwe. all of the colonies contained ticks infected with african swine fever (asf) virus that was readily transmitted by bite to domestic pigs. although they were maintained on virus-free pig blood, asf virus infections persisted in the colonies for at least 1 yr. despite the fact that asf virus passes transstadially, sexually, and tra ...	1989	2769711
virus-specific cellular blastogenesis and interleukin-2 production in swine after recovery from african swine fever.	animals recovered from viral diseases represent an important model to study the host cellular and humoral immune responses to the etiologic agents. this is particularly important for african swine fever virus (asfv) infections in which antibodies have little or no virus-neutralizing effect. pigs surviving experimental infection with the naturally occurring low-virulent, nonhemadsorbing asfv/nh/p68 (nhv) isolate did, however, exhibit virus-specific t-cell activities, as measured by a variety of a ...	1989	2802312
genetic variation of african swine fever virus: variable regions near the ends of the viral dna.	restriction endonuclease maps of the variable dna regions of african swine fever virus field isolates from the iberian peninsula showed that the changes in length are located in the terminal-inverted repetitions and in unique sequences close to the dna ends. analysis of nine clones derived from the spleen of an infected pig revealed the existence of frequent length changes within the inverted terminal repetitions. in each clone, changes occurred symmetrically at both terminal-inverted repetition ...	1989	2815584
comparison of a radioimmunoprecipitation assay to immunoblotting and elisa for detection of antibody to african swine fever virus.	a radioimmunoprecipitation assay (ripa) has been developed for detection of antibody to african swine fever virus (asfv) and compared with the immunoblot assay with regard to sensitivity and specificity. two hundred seven field sera, obtained from pigs in spain from different geographic areas between 1975 and 1986, that were positive by asfv enzyme-linked immunosorbent assay (elisa) were also analysed by immunoblot assay and ripa. by serum dilution experiments, the ripa appeared at least as sens ...	1990	2094444
inhibition of african swine fever virus in cultured swine monocytes by phosphonoacetic acid (paa) and by phosphonoformic acid (pfa).	the use of phosphonoacetic (paa) and phosphonoformic acid (pfa) as inhibitors of african swine fever virus (asfv) replication in porcine monocytes/macrophages (mo) was investigated. at concentrations sufficient to inhibit replication, hemadsorption, and cytopathogenic damage by high inocula of asfv, both antiviral agents were cytostatic and suppressed the dna-synthetic growth response of porcine mo to the mo-specific colony-stimulating factor-1 (csf-1). paa and pfa inhibited asfv-associated dna- ...	1990	2148081
genetic variation and multigene families in african swine fever virus.	the genome of a virulent strain (lis57) of african swine fever virus differs from that of the vero-cell-adapted strain (ba71v) in several deletions located in the variable regions. the region which contains the most differences is located 8-20 kb from the left end. the dna sequence of this region was obtained from lis57 virus dna and compared with the overlapping sequences of ba71v virus. this comparison revealed that the changes in the variable regions result in differences in the number of gen ...	1990	2219721
in vitro dna replication by cytoplasmic extracts from cells infected with african swine fever virus.	a cell-free system that catalyzes dna replication was prepared from cytoplasmic extracts of vero cells infected with african swine fever virus (asfv). the cells were permeabilized with lysolecithin and disrupted by mild mechanical action and the nuclei were removed by low-speed centrifugation. extracts prepared from infected cells at the time of maximal dna replication incorporated [alpha-32p]dttp into acid-insoluble material that was sensitive to dnase and resistant to rnase. the reaction was i ...	1990	2219742
variable regions on the genome of malawi isolates of african swine fever virus.	restriction enzyme site mapping showed that most bamhi and all clai sites were conserved on the genomes of 17 african swine fever virus isolates from separate disease outbreaks that occurred between 1982 and 1989 in malawi. however, frequent variation between virus genomes did occur due to addition or deletion of dna sequences at various positions along the genome and 11 virus genotypes could thus be distinguished among the 17 isolates analysed. length variations occurred at 10 different loci on ...	1990	2230738
[polypeptides of african swine fever virus].	the published data on the characteristics and properties of structural and nonstructural polypeptides of the african porcine virus are reviewed. localization of the viral proteins in virions and infected cells, kinetics of biosynthesis, glycosylation, phosphorylation and the antigenicity of the proteins are discussed.	1990	2233783
comparison of two antigens for use in an enzyme-linked immunosorbent assay to detect african swine fever antibody.	two african swine fever virus (asfv) antigens were tested for use in an elisa to detect antibody to asfv. antigens used were the cytoplasmic soluble fraction (cs-p) of infected cells grown in the presence of porcine serum and the semipurified viral structural protein vp73 (svp73). both antigens were tested by elisa against 72 sera obtained during several asf field episodes and from asfv-inapparent carriers. of the 72 sera, only 2.8% has positive results by elisa against cs-p antigen; 60% of posi ...	1990	2240773
inhibitory effect of african swine fever virus on lectin-dependent swine lymphocyte proliferation.	the incubation of swine peripheral blood mononuclear cells (pbmc) with african swine fever (asf) virus preparations strongly inhibited the proliferative response of lymphocytes to pha and other lectins. the inhibition, which persisted after inactivation of the virus by uv radiation, was dependent upon the dose and the time that virus preparations were present in cultures. when virus preparations were fractionated by ultracentrifugation, the inhibitory activity resulted to be soluble, whereas no ...	1990	2251767
identification of a variable region of the african swine fever virus genome that has undergone separate dna rearrangements leading to expansion of minisatellite-like sequences.	nucleotide sequencing identified a tandemly repeated sequence array 22 x 10(3) base-pairs from the right-hand dna terminus of the african swine fever virus (asfv) genome. the sequence of the repeat array and sequences closely flanking it were compared in the genomes of four groups of asfv isolates that had very different restriction enzyme site maps. arrays present in one group of asfv isolates from east zambia/malawi varied in length and contained between 8 and 38 copies of a 17-nucleotide repe ...	1990	2258935
effect of macrophage-specific colony-stimulating factor (csf-1) on swine monocyte/macrophage susceptibility to in vitro infection by african swine fever virus.	swine cells of the monocyte/macrophage lineage (mm) proliferate and survive for several weeks in vitro in medium supplemented with the murine macrophage-specific hematopoietic growth factor, colony-stimulating factor 1 (csf-1). the extent to which mm, cultured in csf-1, supported african swine fever virus (asfv) growth in vitro was investigated. mm, cultured in medium with csf-1, were sensitive to infection and viral-induced cytopathogenic damage by both natural field isolates of asfv and fibrob ...	1990	2281603
interaction of african swine fever virus with macrophages.	morphological data obtained by electron microscopy have shown that african swine fever virus adapted to vero cells enters swine macrophages, its natural host cell, by a mechanism of receptor-mediated endocytosis. binding studies with 3h-labeled virus and competition experiments with uv-inactivated virus have shown that the virus entry that leads to a productive infection in swine macrophages is mediated by saturable binding sites on the plasma membrane. the virus also penetrated into rabbit macr ...	1990	2291335
african swine fever virus: purification of capsomeres released by lipase.	the virus capsomeres of the outer and inner layers of capsids were effectively released simultaneously from purified virions by lipase digestion and were purified by a linear gradient ultracentrifugation. the capsid consisted of an array of double layers of uniformly arranged individual capsomeres where a lipid(s) served as a matrix in between the capsomeres.	1990	2309446
multigene families in african swine fever virus: family 110.	the genome of african swine fever virus was screened for the existence of repetitive sequences by hybridization between different cloned restriction fragments covering the viral dna. several sets of repeated sequences were detected in fragments located close to the dna ends. one of these groups of repetitions involved fragments located at both ends of the genome. the remaining groups involved fragments that were located exclusively at the left end. the sequence of a 3.2-kilobase segment spanning ...	1990	2325202
multigene families in african swine fever virus: family 360.	a group of cross-hybridizing dna segments contained within the restriction fragments rk', rl, rj, and rd' of african swine fever virus dna were mapped and sequenced. analysis of these sequences revealed the presence of a family of homologous open reading frames in regions close to the dna ends. the whole family is composed of six open reading frames with an average length of 360 coding triplets (multigene family 360), four of which are located in the left part of the genome and two of which are ...	1990	2325203
mapping and sequence of the gene coding for protein p72, the major capsid protein of african swine fever virus.	the gene encoding protein p72, the major structural protein of african swine fever virus and one of the most immunogenic proteins in natural infection has been mapped and sequenced. the gene was mapped by using oligonucleotide probes deduced from amino acid sequences of tryptic peptides obtained from purified protein p72. this allowed the location of the gene in fragment ecori b of african swine fever virus dna. the nucleotide sequence obtained from this region revealed an open reading frame enc ...	1990	2327074
analysis of naturally occurring deletion variants of african swine fever virus: multigene family 110 is not essential for infectivity or virulence in pigs.	a comparison of uncloned african swine fever virus isolates with their cloned counterparts revealed the presence of genetic variants in three out of seven uncloned field virus populations tested. five different virus clones were isolated from the uncloned kir69 virus stock by limit dilution. structural analysis of the variants showed that they differed by single deletions of 10-16 kilobases in the region located between 6.8 and 27 kilobases from the left dna terminus. there was no homology betwe ...	1990	2330671
evaluation of sensitivity of different antigen and dna-hybridization methods in african swine fever virus detection.	elisa, immunodot and dna hybridization methods have been adapted to detect african swine fever virus (asfv), and their sensitivities were compared using virus obtained from cell cultures. about 2.3 x 10(2) 50% hemadsorbing doses (had50) of virus were detected with elisa sandwich using an anti-asfv igg biotinylated followed by avidin-peroxidase. the immunodot technique showed similar sensitivity, detecting about 4.6 x 10(2) had50 of virus. asfv-dna was detected using radioactive dna probes and mo ...	1990	2347889
pulmonary intravascular macrophages in lungs of pigs inoculated with african swine fever virus of differing virulence.	the role of pulmonary intravascular macrophages (pim) in a viral infection has been studied by structural and ultrastructural methods with two strains of the african swine fever (asf) virus: the virulent strain e70 and the attenuated strain e75. pulmonary intravascular macrophages were the cells of the mononuclear phagocyte system of the lung most involved in the replication of strain e70, showing a marked cytopathic effect and necrosis. concurrently, their size and number increased sharply. thi ...	1990	2365848
absence of ornithodoros moubata, the vector of african swine fever virus, from the main pig producing area of cameroon.	no evidence for the presence of soft ticks of the ornithodoros moubata complex was found during a survey of african swine fever carried out between 1985 and 1988 in the west province and southern parts of the north west and south west provinces of cameroon. the survey consisted of interviews of veterinary assistants and farmers, distribution of a questionnaire and tick searches both manually and with carbon dioxide traps. the absence of warthogs (phacochoerus aethiopicus) from these areas was al ...	1990	2371751
evidence for an acid phosphatase in african swine fever virus.	an acid phosphatase activity has been detected in purified preparations of african swine fever virus. purified viral cores obtained after nonidet-p40 and 2-mercaptoethanol treatment of the virus retained the activity as assayed with nitrophenyl phosphate as substrate at ph 5. enzyme cytochemistry by electron microscopy showed that the acid phosphatase activity is localized mainly inside the core of the virion. the molecular weight and the isoelectric point of the virus acid phosphatase activity ...	1990	2386433
sequence and evolutionary relationships of african swine fever virus thymidine kinase.	the thymidine kinase gene of african swine fever virus was mapped in a 1.4-kb ecori-psti fragment located in the left half of the eco ri k fragment of african swine fever virus dna by using degenerate oligonucleotide probes derived from regions of the thymidine kinase sequence conserved in several poxviruses, man, mouse, and chicken. the nucleotide sequence of this region revealed an open reading frame of 196 codons, whose translated amino acid sequence showed significant similarity to the thymi ...	1990	2389555
interferon cures cells lytically and persistently infected with african swine fever virus in vitro.	human interferon alpha (ifn-alpha) and interferon gamma (ifn-gamma) inhibit african swine fever (asf) virus replication in vero cells. ifn-alpha and ifn-gamma exert a synergistic inhibition. human tumor necrosis factor (tnf) does not inhibit asf virus replication in this cell line, but in combination with ifns it has antiviral enhancing activity. analysis of the mechanism of inhibition suggests that the action of these cytokines blocks a step that comes prior to dna replication. the 2'-5' a synt ...	1990	1695091
antiviral activity of sulfated polysaccharides against african swine fever virus.	the polyanionic substances lambda and kappa carrageenan, pentosan polysulfate, fucoidan, dextran sulfate and heparin were investigated for their inhibitory effect on the replication of african swine fever virus (asfv) in vitro. lambda carrageenan was the most efficacious with a selectivity index, as based on the ratio of the 50% cytotoxic concentration to the 50% antiviral effective concentration, of 120, followed by pentosan polysulfate with 30, kappa carrageenan 13.3 and fucoidan 10. dextran s ...	1991	1713439
a general method to cleave a known dna sequence at any site.	we describe a new method for obtaining dna fragments starting at a desired point where there is no recognition sequence for any known restriction endonuclease. a single-stranded dna containing the fragment of interest is annealed to a synthetic oligonucleotide hybridizing at the 5' end of the required fragment. then, a partially double-stranded dna is synthesized using the klenow fragment of dna polymerase i in the presence of the four deoxynucleoside triphosphates. the remaining single-stranded ...	1991	1665337
repetitive nucleotide sequencing of a dispensable dna segment in a clonal population of african swine fever virus.	repetitive nucleotide sequencing of a dispensable genomic segment of a clonal population of african swine fever (asf) virus has been carried out to estimate the mutant frequency to neutral alleles. since no mutations have been detected in a total of 54026 nucleotides screened, the maximum mutant frequency is 5.5 x 10(-5) substitutions/nucleotide (95% confidence level). the result renders very unlikely the occurrence of hypermutational events during asf virus dna replication, at least within the ...	1991	1685049
production of monoclonal antibodies specific for african swine fever virus following in vitro primary immunization of mouse splenocytes in the presence of stimulated t lymphocyte supernatants.	splenocytes from non-immune mice were stimulated in vitro using a kit of cytokine preparations (obtained from murine mlr and el-4 cell cultures), and concomitantly immunized with african swine fever (asf) virus antigen. in addition, fusions were performed at 5 days after primary or secondary stimulation/immunization. the detection of specific antibodies in the culture supernatants was not successful. in contrast, specific antibody-producing hybridomas could be generated, and this was at least co ...	1991	1765668
experimental transmission of african swine fever virus by the tick ornithodoros (alectorobius) puertoricensis (acari: argasidae).	the soft tick ornithodoros puertoricensis fox has been found on the caribbean island of hispaniola (haiti and the dominican republic) where african swine fever (asf) was endemic from 1978 to 1984. to evaluate the vector potential of o. puertoricensis for african swine fever virus (asfv), second-instar nymphs were experimentally infected by feeding on a viremic pig that was infected with the dominican republic isolate (dr-ii) of asfv. subsequent infection rates and mean virus titers for individua ...	1991	1770521
inhibition of natural killer activity in porcine mononuclear cells by african swine fever virus.	the coincubation at 37 degrees c for 24 hours of swine peripheral blood mononuclear cells with african swine fever virus inhibited in part the natural killer activity shown by cells incubated without the virus. this inhibition depended on the dose of the virus and on the time that cells were incubated with it. when the virus preparation was fractionated by ultracentrifugation, most of the inhibitory activity was found in the sedimented fraction, where viral particles were present; however, the l ...	1991	1780588
virus survival in the environment.	viruses pass into the environment from clinically ill or carrier hosts; although they do not replicate outside living animals or people, they are maintained and transported to susceptible hosts. population concentrations and movement, both animal and human, have been steadily increasing in this century, enhancing transmission of respiratory and enteric viruses and compounding the difficulty of preventing environmental transmission. studies on environmental survival factors of viruses have been m ...	1991	1782426
[the population structure of the african swine fever virus based on the quantitative hemadsorption trait].	subpopulation composition of 8 asfv isolates and variants differing in virulence was evaluated comparatively by their haemadsorption capacity. the "quantitative haemadsorption marker" was shown to be useful for characterization of the strains, virus population phenotypic heterogeneity and structure. the marker expression was found to correlate with virulence: attenuated variants had low haemadsorption and more subpopulation components with that shift, and vice versa.	1991	1796589
glomerular pathology in surviving pigs experimentally infected with african swine fever virus.	twelve miniature pigs were inoculated with an attenuated african swine fever virus to study glomerular involvement in surviving pigs. in acute phase, kidneys were severely affected and displayed a glomerular capillary thrombosis with fibrin deposition in vascular lumen, detected by immunofluorescence. fibrin-positive deposits were progressively cleared between one to three months after infection in surviving pigs. the histological picture in kidneys of surviving pigs, up to one post-infection ye ...	1991	1806048
vaccinia virus-mediated expression of african swine fever virus genes.	bacteriophage lambda and plasmid clones containing african swine fever virus (asfv) dna inserts, which together covered more than 90% of the genome of a malawi asfv isolate (lil 20/1), were transfected into vaccinia virus (vv)-infected cells. expression of asfv-encoded proteins was assayed at late times after vv infection by immunoprecipitation of [35s]methionine-labeled proteins with hyperimmune serum from asfv-infected pigs, separation of immunoprecipitated proteins by denaturing polyacrylamid ...	1991	1826575
isolation and molecular characterization of the swinepox virus thymidine kinase gene.	swinepox virus (spv), the only member of the suipoxvirus genus, shows little antigenic relatedness or dna homology to members of the other poxvirus genera. a spv thymidine kinase (tk) gene was detected and mapped to the left end of the hindiii g fragment using degenerate oligonucleotide probes. cloning and sequencing of a 1.8-kb hindiii-bamhi fragment containing the spv tk gene revealed an open reading frame (orf) of 181 amino acids yielding a predicted polypeptide of mr 20.6 kda with significan ...	1991	1853562
the sequences of the ribonucleotide reductase genes from african swine fever virus show considerable homology with those of the orthopoxvirus, vaccinia virus.	two african swine fever virus (asfv) recombinant plasmids containing large inserts of dna have been sequenced at random, and translations of the dna sequence have been compared to libraries of vaccinia virus protein sequences. among other genes identified by their extensive homology with vaccinia virus genes were the large and small subunits of ribonucleotide reductase. a 5.5-kb fragment from the malawi (lil20/1) strain of asfv was identified as containing the genes for both these subunits. the ...	1991	1871976
detection of african swine fever virus by a biotinylated dna probe: assay on cell cultures and field samples.	african swine fever virus was detected in various samples using a molecular hybridization technique. a fragment located in a constant area of the viral genome was biotin-labelled. this probe, when present at a concentration of 100 ng/ml of the hybridization solution, could detect 10 pg of target dna immobilized on nitrocellulose with cellular dna and rna. the virus was evidenced after being passaged on monkey kidney cells, either 8 h post-inoculation (pi) if the multiplicity of infection (moi) w ...	1991	1897870
rapid isolation of monoclonal hybridoma cultures by a 'fusion-cloning' method: the requirement for aminopterin.	hybridomas were generated by fusing the balb/c sp2/0 myeloma-like cell line with either: (i) splenocytes from balb/c mice immunized with foot-and-mouth disease virus (fmdv), rinderpest virus (rpv), peste des petits ruminants virus (pprv), african swine fever virus (asfv) or pig thymocytes; or (ii) lymph node cells from cattle immunized with fmdv. if the fusion mixtures were plated in cloning medium of methyl cellulose and hat medium, small hybridoma colonies developed which rarely survived. fusi ...	1991	1954000
african swine fever virus fatty acid acylated proteins.	labeling experiments with [3h]palmitic and [3h]myristic acids of african swine fever virus-infected vero cells have shown that 11 proteins induced during infection are covalently bound to myristic acid and that palmitic acid was not attached to viral proteins. the time course of synthesis of the myristylated polypeptides and the requirements of viral dna replication indicated that the myristylated proteins, with the exception of a 13-kda protein, belong to the late class of viral proteins. the m ...	1991	1962463
expression and characterization of the thymidine kinase gene of african swine fever virus.	the thymidine kinase (tk) gene of african swine fever virus (asfv) was located within the viral genome by using two degenerate oligonucleotide probes derived from sequences of the vaccinia virus and cellular tk genes. the tk gene was mapped within a 0.72-kbp bglii-xhoi fragment (0.242 to 0.246 map units) derived from a 23.9-kbp sali-b fragment of the asfv genome. identification of this region as the asfv tk gene was confirmed by expression of tk in escherichia coli and by the synthesis of active ...	1991	1987368
protein p22 of african swine fever virus: an early structural protein that is incorporated into the membrane of infected cells.	the open reading frame k'177, located at the left end of the african swine fever virus genome, codes for an early induced structural protein of 22,000 da (p22), which is released from the viral particle by the nonionic detergent n-octyl-beta-d-glucopyranoside under conditions that solubilize external viral structural proteins. the predicted amino acid sequence of the protein contains a hydrophobic region at its n-terminus with characteristics of a signal peptide and, at early times after virus i ...	1991	1994575
fc receptors do not mediate african swine fever virus replication in macrophages.	titration experiments in swine macrophages have shown that african swine fever virus infectivity was not enhanced in the presence of antiviral antibodies. the early viral protein synthesis and the viral dna replication in swine macrophages infected with virus-antibody complexes were inhibited in the presence of high doses of uv-inactivated virus, which saturated specific virus receptors, but not when fc receptors were saturated with antibodies. these results indicate that african swine fever vir ...	1991	2014648
african swine fever virus attachment protein.	treatment of african swine fever virus particles with nonionic detergents released proteins p35, p17, p14, and p12 from the virion. of these proteins, only p12 bound to virus-sensitive vero cells but not to virus-resistant l or ibrs2 cells. the binding of p12 was abolished by whole african swine fever virus and not by similar concentrations of subviral particles that lacked the external proteins. a monoclonal antibody (24bb7) specific for p12 precipitated a protein that, when analyzed by sodium ...	1991	2016759
the primary structure of the thymidine kinase gene of fish lymphocystis disease virus.	the dna nucleotide sequence of the thymidine kinase (tk) gene of fish lymphocystis disease virus (fldv) which has been localized between the coordinates 0.678 to 0.688 of the viral genome was determined. the analysis of the dna nucleotide sequence located between the recognition sites of hindiii (0.669 map unit; nucleotide position 1) and acci (nucleotide position 2032) revealed the presence of an open reading frame of 954 bp on the lower strand of this region between nucleotide positions 1868 ( ...	1991	2024501
role of b and t lymphocytes in the specific immunosuppression induced by a protein released by porcine monocytes infected with african swine fever virus.	some immunobiological aspects of host responses to an immunosuppressive protein (p36) released by porcine monocytes upon infection with african swine fever virus were analysed in a murine system. treatment of normal, adult c57bl/6 mice with p36 (i) significantly delayed allogenic skin graft rejection; (ii) suppressed the specific plaque-forming cell response to immunization with heterologous erythrocytes; but (iii) induced marked increases in the numbers of 'background' splenic ig-secreting plaq ...	1991	2025617
in vivo study of hemadsorption in african swine fever virus infected cells.		1991	2063520
mapping and molecular characterization of a functional thymidine kinase from amsacta moorei entomopoxvirus.	a thymidine kinase (tk) gene from the entomopoxvirus of amsacta moorei (amepv) has been identified, mapped, cloned, and sequenced. the amepv tk was shown to be biologically functional as cloning of the gene into a tk-derivative of the orthopoxvirus vaccinia creates a tk+ virus. the gene has been localized to a 1.5-kb ecori-q dna fragment which maps to the far left end of the viral genome. sequence analysis reveals an open reading frame (orf) of 182 amino acids potentially encoding a polypeptide ...	1992	1733099
rapid and biologically safe diagnosis of african swine fever virus infection by using polymerase chain reaction.	in order to circumvent the need for infectious virus for the diagnosis of african swine fever (asf), we established the polymerase chain reaction (pcr) technique for the detection of asf virus (asfv) dna. a 740-bp fragment that originated from the conserved region of the viral genome was partially sequenced. from this sequence, four pcr primers and one oligonucleotide probe were designed and synthesized. a specific 640-bp pcr product was amplified by using oligonucleotides 1 and 5 as primers and ...	1992	1734041
induction of ribonucleotide reductase activity in cells infected with african swine fever virus.	infection of vero cells with african swine fever virus (asfv) resulted in a marked increase in ribonucleotide reductase activity. the induction of ribonucleotide reductase was detected early after infection and was proportional to the multiplicity of infection. inhibition of viral dna replication did not affect the induction of the enzyme. several characteristics could distinguish the virus-induced from the normal cell enzyme. asfv-induced ribonucleotide reductase was inhibited by magnesium, was ...	1992	1736545
interferon-gamma production by african swine fever virus-specific lymphocytes.	peripheral blood mononuclear cells (pbmc) from inbred pigs that were immunized with autologous macrophages infected with the african swine fever (asf) virus ba71v, a nonvirulent virus isolate, proliferated and produced interleukin-2 in response to homologous and heterologous isolates of the asf virus. they produced, however, interferon (ifn) only when challenged in vitro with homologous or attenuated isolates of the asf virus, but not with heterologous or virulent isolates. the ifn was ph 2 labi ...	1992	1738818
[the functional role of the glycosylation of viral components].	an inhibitory analysis of the role of glycosylation and glycoproteins in the manifestations of the most important properties of african swine virus was carried out using a set of strains and variants with contrasting characteristics. glycoproteins were shown to realize some virus functions such as virulence and its variability, intracellular transport and exocytosis of virions, hemadsorption, but not immunological recognition of the infected cells by cytotoxic t-lymphocytes.	1992	1290229
genes homologous to ubiquitin-conjugating proteins and eukaryotic transcription factor sii in african swine fever virus.	the nucleotide sequence of the 6004-bp ecori i fragment of african swine fever virus dna has been determined. translation of the sequence revealed eight closely spaced open reading frames (orfs), three of them reading rightward and five leftward. northern blot hybridization analysis indicated that orfs i73r and i78r were transcribed early in infection, whereas orfs i177l, i196l, and i329l were expressed at late times. transcripts for orfs i215l, i226r, and i243l were detected at low levels in ea ...	1992	1309282
a ubiquitin conjugating enzyme encoded by african swine fever virus.	the post-translational modification of proteins by covalent attachment of ubiquitin occurs in all eukaryotes by a multi-step process. a family of e2 or ubiquitin conjugating (ubc) enzymes catalyse one step of this process and these have been implicated in several diverse regulatory functions. we report here the sequence of a gene encoded by african swine fever virus (asfv) which has high homology with ubc enzymes. this asfv encoded enzyme has ubc activity when expressed in escherichia coli since ...	1992	1310934
a gene homologous to topoisomerase ii in african swine fever virus.	a putative topoisomerase ii gene of african swine fever virus was mapped using a degenerate oligonucleotide probe derived from a region highly conserved in type ii topoisomerases. the gene is located within ecori fragments p and h of the african swine fever virus genome. sequencing of this region has revealed a long open reading frame, designated p1192r, encoding a protein of 1192 amino acids, with a predicted molecular weight of 135,543. open reading frame p1192r is transcribed late after infec ...	1992	1316688
evolution of thymidine and thymidylate kinases: the possibility of independent capture of tk genes by different groups of viruses.	phylogenetic analysis of viral and cellular thymidine and thymidylate kinases was performed using computer-assisted methods. multiple alignments and tentative phylogenetic trees were generated for the two families of these enzymes, which include a) thymidine kinases (tk) of mammals, poxviruses, african swine fever virus, e. coli, and bacteriophage t4; and b) thymidylate kinases (thyk) of yeast and poxviruses and distantly related herpesvirus proteins with both enzymatic activities. analysis of t ...	1992	1317076
identification of an african swine fever virus gene with similarity to a myeloid differentiation primary response gene and a neurovirulence-associated gene of herpes simplex virus.	here we describe an open reading frame (lmw23-nl) in the african swine fever virus genome that possesses striking similarity to a murine myeloid differentiation primary response gene (myd116) and the neurovirulence-associated gene (icp34.5) of herpes simplex virus. in all three proteins, a centrally located acidic region precedes a highly conserved, hydrophilic 56-amino-acid domain located at the carboxy terminus. lmw23-nl predicts a highly basic protein of 184 amino acids with an estimated mole ...	1992	1323711