Publications

passively transferred african swine fever virus antibodies protect swine against lethal infection.	the role of anti-viral antibodies in homologous protective immunity to a virulent african swine fever virus (asfv) strain e75 was examined by passive transfer experiments in swine. eighty-five percent of animals (n = 14) that received anti-asfv immunoglobulin (ig) survived challenge infection, while 100% mortality was observed in control group animals (n = 28) that received anti-pseudorabies virus ig, normal swine ig, or phosphate-buffered saline. with the exception of a significantly delayed an ...	1994	8259670
two putative african swine fever virus helicases similar to yeast 'deah' pre-mrna processing proteins and vaccinia virus atpases d11l and d6r.	two open reading frames (orfs) of african swine fever virus (asfv) encoding putative helicases have been sequenced. the two genes, termed d1133l and b962l, are located in the central region of the viral genome, but are separated by about 40 kb of dna. both genes are expressed late during asfv infection of vero cells, after replication of viral dna has begun. contiguous to d1133l, three other orfs (d129l, d79l and d339l), encoding putative proteins of unknown function, have been sequenced. protei ...	1993	8262374
nucleotide sequence of a nucleoside triphosphate phosphohydrolase gene from african swine fever virus.	a putative nucleoside triphosphate phosphohydrolase (ntpase) gene of african swine fever virus was identified by using a degenerate oligonucleotide probe derived from the nucleoside triphosphate binding motif, which is highly conserved among viral and cellular ntpases. the probe hybridized with fragments sali e and ecori q, which is entirely contained in the former one. sequencing of this region revealed an open reading frame, designated q706l, coding for a protein of 706 amino acids, with a cal ...	1993	8266720
characterization of vaccinia virus gene b12r.	we report the characterization of vaccinia virus gene b12r which is predicted to encode a 33k protein with 36% amino acid identity to the serine/threonine protein kinase encoded by vaccinia virus gene b1r. s1 nuclease protection experiments showed that gene b12r is transcribed early during infection from an initiation site 11 bp upstream of the open reading frame (orf). the gene encodes a 33k polypeptide that is not required for virus replication in tissue culture nor for virus virulence in a mu ...	1993	8277291
the dna polymerase-encoding gene of african swine fever virus: sequence and transcriptional analysis.	the putative dna polymerase-encoding gene of african swine fever virus has been sequenced. the gene, designated g1207r, is located in the central region of the viral genome, and encodes a protein of 1207 amino acids (aa) with a predicted m(r) of 139,835. the gene is transcribed at both early and late stages of infection into a 4.1-kb rna. transcription is initiated at tsp, 8 nucleotides (nt) upstream from the start codon. open reading frame (orf) g1207r contains four direct repeats in tandem clo ...	1993	8293992
[lipids from the african swine fever virus].	the lipids of highly purified african swine fever virus (asfv) propagated in porcine bone marrow cells were observed to contain 25.6% phospholipids, 9.7% monoglycerides, 14.1% cholesterol, 17.8% free fatty acids, 14.4% diglycerides, 13.6% triglycerides, and 6.7% cholesterol ethers. diethyl ether extracts mono-, di-, triglycerides, free fatty acids, 50% of cholesterol and cholesterol ethers, and 25% of phospholipids from the virus. analysis of the 14c-sodiumacetate incorporation into viral, cellu ...	1993	8302309
cloning and nucleotide sequence determination of the major envelope glycoprotein (gp55) gene of hog cholera virus (weybridge).	a 1.7 kb cdna fragment corresponding to the coding region of the major envelope glycoprotein (gp55) of pestivirus hog cholera (weybridge) was obtained using the polymerase chain reaction (pcr), and then cloned into puc 8. the deduced amino acid sequence of gp55 showed a strong homology to that of hcv strains brescia (94%) and alfort (90%), and to a lesser extent to the closely related gp53 of bovine viral diarrhoea virus strain, nadl (65%). eighteen cysteine residues were identified in the seque ...	1993	8317145
production and characterization of monoclonal antibodies against hog cholera virus (alfort 187 strain).		1993	8328912
african swine fever virus encodes a serine protein kinase which is packaged into virions.	nucleotide sequencing of the sali j region of the virulent malawi (lil20/1) strain of african swine fever virus (asfv) identified an open reading frame (orf), designated j9l, with extensive similarity to the family of protein kinases. this orf encodes a 35.1-kda protein of 299 amino acids which shares 24.6% amino acid identity with the human pim-1 proto-oncogene and 21.0% identity with the vaccinia virus b1r-encoded protein kinase. the asfv orf contains the motifs characteristic of serine-threon ...	1993	8331722
an african swine fever virus gene with a similarity to eukaryotic rna polymerase subunit 6.		1993	8332503
polyprotein processing in african swine fever virus: a novel gene expression strategy for a dna virus.	this report shows that african swine fever virus (asfv)--a large dna-containing virus--synthesizes a polyprotein to produce several of its structural proteins. by immunoprecipitation analysis, we have found that asfv polyprotein is a 220 kda myristoylated polypeptide (pp220) which, after proteolytic processing, gives rise to four major structural proteins: p150, p37, p34 and p14. processing of the asfv polyprotein takes place at the consensus sequence gly-gly-x and occurs through an ordered casc ...	1993	8335009
the skin, tongue, and brain as favorable organs for hog cholera diagnosis by immunofluorescence.	hog cholera virus antigens were found densely distributed in skin and tongue of pigs experimentally infected with hog cholera virus. the finding described here warrants the usage of ear biopsies for hog cholera diagnosis on a herd basis.	1993	8347086
glycoprotein e1 of hog cholera virus expressed in insect cells protects swine from hog cholera.	the processing and protective capacity of e1, an envelope glycoprotein of hog cholera virus (hcv), were investigated after expression of different versions of the protein in insect cells by using a baculovirus vector. recombinant virus bace1[+] expressed e1, including its c-terminal transmembrane region (tmr), and generated a protein which was similar in size (51 to 54 kda) to the size of e1 expressed in swine kidney cells infected with hcv. the protein was not secreted from the insect cells, an ...	1993	8350404
inhibition of african swine fever virus binding and infectivity by purified recombinant virus attachment protein p12.	the african swine fever virus protein p12, involved in virus attachment to the host cell, has an apparent molecular mass of 17 kda in sodium dodecyl sulfate-polyacrylamide gel electrophoresis under nonreducing conditions. we have also identified 12- and 10-kda forms of the p12 protein in infected vero cells and found that the mature 17-kda protein is the only form present in virus particles. the p12 protein has been produced in large amounts in spodoptera frugiperda insect cells infected with a ...	1993	8350406
identification of a structural glycoprotein of an rna virus as a ribonuclease.	one of the three structural glycoproteins of classical swine fever virus (csfv) is e0, a disulfide-bonded homodimer that induces virus-neutralizing antibodies and occurs in a virion-bound as well as a secreted form. e0 was shown to be similar to a family of fungal and plant ribonucleases. purified e0 from csfv-infected cells was a potent ribonuclease specific for uridine and inhibitable by zinc ions.	1993	8356450
characterization of a soluble hemagglutinin induced in african swine fever virus-infected cells.	hemadsorption (had) of erythrocytes to the surface of african swine fever virus (asfv)-infected cells is a well-known phenomenon but hemagglutination of pig erythrocytes in the supernatant of asfv-infected cells has not been reported before. we report here the discovery of a pig erythrocyte-agglutinating activity released to the in vitro cell culture medium by cells infected with some isolates of asfv. this finding allowed the identification and characterization of a soluble hemagglutinin (ha) m ...	1993	8372447
three african swine fever virus genes encoding proteins with homology to putative helicases of vaccinia virus.	sequence analysis of the sali g, h, i and j restriction fragments of the african swine fever virus (asfv) genome from the virulent isolate malawi (lil20/1) identified three open reading frames (orfs) encoding predicted proteins of 125.0k (g10l), 80.4k (j10l) and 58.0k (j11l) which showed homology to members of the dna and rna helicase superfamily. orfj10l was related to protein 4 of the kluyveromyces lactis killer plasmid pkg12 and to two putative helicases, d6r and d11l, of vaccinia virus. orf ...	1993	8376971
african swine fever virus guanylyltransferase.	the gene coding for the guanylyltransferase of african swine fever virus has been identified and sequenced. the gene, designated np868r, is located within fragments ecori n' and d of the virus genome (ba71v strain) and encodes a protein with a predicted molecular mass of 99.9 kda that shares significant similarity with the large subunit of both vaccinia and shope fibroma virus capping enzymes, with percentages of identity of 20.6 and 21.8%, respectively. a protein of 95 kda was induced in escher ...	1993	8382399
clinical, virological and serological findings after intranasal inoculation of pigs with bovine viral diarrhoea virus and subsequent intranasal challenge with hog cholera virus.	five groups of weaner pigs were intranasally inoculated with constant doses of bovine viral diarrhoea virus (bvdv) strain osloss/2482. four weeks post primary inoculation (p.p.i.) the animals were intranasally challenged with decreasing doses of hog cholera virus (hcv) strain alfort/187. clinical signs were not observed apart from a short febrile period (2 days, > 40 degrees c) in one animal. another animal died intercurrently without showing any pathological signs. virus isolation from leucocyt ...	1993	8384395
presumptive diagnostic differentiation of hog cholera virus from bovine viral diarrhea and border disease viruses by using a cdna nested-amplification approach.	hog cholera virus (hcv), bovine viral diarrhea virus (bvdv), and border disease virus (bdv) are closely related pestiviruses. bvdv and bdv are found worldwide but seldom cause disease in swine. in contrast, hcv has been successfully eradicated from swine in several nations but poses a potentially devastating threat to them because of its great virulence. rapid differential diagnosis of hcv from bvdv and bdv infections in swine is vital for detection of the possible reintroduction of hcv into nat ...	1993	8384625
rna insertions and gene duplications in the nonstructural protein p125 region of pestivirus strains and isolates in vitro and in vivo.	sixteen cytopathogenic (cp) bovine viral diarrhea virus (bvdv) strains/isolates were screened for the existence of rna insertions in the p125 gene region and/or for p80 gene duplications using the polymerase chain reaction after reverse transcription. three strains/isolates were shown to contain insertions, and in three others gene duplications were demonstrated. one strain was shown to contain a gene duplication in addition to an insertion. insertions or duplications were absent in the genomes ...	1993	8384762
processing of the envelope glycoproteins of pestiviruses.	the genomic rna of pestiviruses is translated into a large polyprotein that is cleaved into a number of proteins. the structural proteins are n terminal in this polyprotein and include three glycoproteins called e0, e1, and e2 on the basis of the order in which they appear in the polyprotein. using pulse-chase experiments, we show that a pestiviral glycoprotein precursor, e012, is formed that is processed into e0, e1, and e2 in an ordered fashion. processing is initiated by a nascent cleavage be ...	1993	8388499
detection of hog cholera virus and differentiation from other pestiviruses by polymerase chain reaction.	reverse transcription coupled with the polymerase chain reaction (rt-pcr) was used for the detection and differentiation of pestiviruses. for this purpose, one primer pair was selected from a highly conserved region of the genome of pestiviruses. using these primers (pest 1-pest 2), dna fragments of between 72 and 74 bp could be amplified from all pestivirus isolates tested. in order to differentiate hog cholera virus (hcv) from bovine viral diarrhea virus (bvdv) and border disease virus (bdv), ...	1993	8388887
an african swine fever virus gene with similarity to the proto-oncogene bcl-2 and the epstein-barr virus gene bhrf1.	an open reading frame, lmw5-hl, in the african swine fever virus genome displays a high degree of similarity to the proto-oncogene bcl-2 and, to a lesser degree, the epstein-barr virus gene bhrf1. a highly conserved central region is found in all three proteins. lmw5-hl encodes a protein of 18 kda that is present in infected porcine macrophages at both early and late times postinfection. the similarity of lmw5-hl to bcl-2 and bhrf1 suggests a role for it in cell maintenance during productive or ...	1993	8389936
african swine fever virus thymidylate kinase gene: sequence and transcriptional mapping.	a putative thymidylate kinase gene of african swine fever virus has been identified at the left end of the sali i' fragment of the virus genome. the gene, designated a240l, has the potential to encode a protein of 240 amino acids with an m(r) of 27,754 and is transcribed early after infection. primer extension analysis indicates that transcription is initiated a short distance from the first atg codon of open reading frame a240l. the deduced amino acid sequence of this open reading frame shows s ...	1993	8393914
three adjacent genes of african swine fever virus with similarity to essential poxvirus genes.	nucleotide sequencing of the right end of the salij fragment of the highly virulent malawi lil20/1 strain of african swine fever virus (asfv) has revealed three adjacent genes with similarity to: serine-threonine protein kinases; members of the putative helicase superfamily sf2; and the vaccinia virus 56 kda abortive late protein. all three genes are transcribed to the left with respect to the orientation of the asfv genome. gene l19il predicts a protein similar to serine-threonine protein kinas ...	1993	8397501
polymerase chain reaction-mediated cloning and in vitro translation of the genes coding for the structural proteins of hog cholera virus.	after amplification by pcr, the 5' region of the genome of hog cholera virus (hcv) strain alfort 187 was cloned and sequenced. the nucleotide and deduced amino acid sequences were compared with the ones of other pestiviruses. by in vitro translation experiments we were able to demonstrate the protease activity of the p 20 protein of hcv.	1993	8397504
antibody prevalence of hog cholera, bovine viral diarrhoea and aujeszky's disease virus in wild boars in northern germany.	during the hunting season 1990/1991 a total of 841 blood samples was collected from shot wild boar corresponding to about 2.11% of the total hunting bag in lower saxony. all the sera were screened for neutralizing antibodies (nab) to hog cholera virus (hcv) and bovine viral diarrhoea virus (bvdv) by direct neutralizing peroxidase linked antibody (npla) assay. for the detection of antibodies (ab) against hcv a complex trapping blocking (ctb) elisa was used. cytotoxic sera were retested using an i ...	1993	8404524
duplicated genes within the variable right end of the genome of a pathogenic isolate of african swine fever virus.	the right variable region of the genome of a pathogenic strain of african swine fever virus (asfv), malawi lil20/1, has been sequenced and 15 open reading frames (orfs) identified by computer analysis. eight of these orfs were found to be similar to previously described asfv orfs and three of these belong to two previously described multiple gene families (mgf), 360 and 110. four of the remaining five orfs belong to a novel mgf, designated mgf 100, and the last orf encodes a protein that is simi ...	1993	8409937
identification of the gene encoding the major capsid protein of fish lymphocystis disease virus.	the gene encoding the major capsid protein (mcp) of fish lymphocystis disease virus (flounder isolate; flcdv-f) has been identified by pcr using oligonucleotide primers corresponding to different regions of the mcp of tipula iridescent virus (tiv), iridescent virus 22 (iv22) and chilo iridescent virus (civ). dna fragments of 0.4 kbp, 0.5 kbp and 0.27 kbp in size were amplified using oligonucleotide primers corresponding to amino acids (aa) 146 to 153 (primer 1) and 274 to 268 (primer 6), or aa 1 ...	1993	8409939
transcriptional mapping of a late gene coding for the p12 attachment protein of african swine fever virus.	the transcriptional characterization of the gene coding for the p12 attachment protein of the african swine fever virus is presented. the results obtained have been used to generate the first detailed transcriptional map of an african swine fever virus late gene. novel experimental evidence indicating the existence of major differences between the mechanisms controlling the transcription of late genes in african swine fever virus and poxviruses is provided.	1993	8416381
high-level expression in escherichia coli of the gene coding for the major structural protein (p72) of african swine fever virus.	the gene encoding the major structural protein (p72) of african swine fever virus (asfv) has been expressed in escherichia coli using a t7 rna polymerase system. the use of a recombinant plasmid which contains the entire gene inserted between the t7 promoter and the transcription terminator of the expression vector allowed us to obtain a high expression level of the intact viral protein. this polypeptide, which appears in the insoluble fraction of the bacterial extracts, showed an intense reacti ...	1993	8428668
african swine fever virus encodes a dna ligase.	sequencing of the ecori n' fragment of african swine fever virus (asfv) dna revealed an open reading frame encoding a protein similar to atp-dependent dna ligases. when the gene encoding this protein was expressed in escherichia coli, a protein of the expected molecular mass was labeled in bacterial extracts upon incubation with [alpha-32p]atp. the recombinant protein comigrated in sds-page with the putative viral dna ligase detected in extracts of infected cells. we demonstrate that the recombi ...	1993	8438592
detection of hog cholera virus antigens in experimentally-infected pigs using an antigen-capture elisa.	an antigen-capture elisa was used to detect hog cholera virus (hcv) antigens in blood and tissues taken from pigs infected with 2 different strains of virus. specific antigens were demonstrated in peripheral blood leucocytes (pbls) and a wide range of tissue samples 4-6 days after infection of pigs with a moderate-high virulent hcv strain (weybridge virus). strong signal to noise (s/n) ratios were obtained in the elisa for pbls and lymphoid tissues such as spleen, tonsil and mesenteric lymph nod ...	1993	8460468
activity of several s-adenosylhomocysteine hydrolase inhibitors against african swine fever virus replication in vero cells.	several inhibitors of s-adenosylhomocysteine (adohcy) hydrolase have been found to selectively suppress the replication of african swine fever virus (asfv) in vero cells. of the compounds tested, 3-deazaneplanocin a proved to be the most potent and selective inhibitor of asfv replication. its selectivity index (si) was 3000. then followed 9-(trans-2',trans-3'-dihydroxycyclopentyl)-3- deazaadenine (si = 2500), the 4'beta-vinyl derivative of 9-(trans-2',trans-3'-dihydroxycyclopentyl)adenine (si = ...	1993	8460931
an african swine fever virus gene with similarity to bacterial dna binding proteins, bacterial integration host factors, and the bacillus phage spo1 transcription factor, tf1.		1993	8464748
african swine fever virus specific porcine cytotoxic t cell activity.	african swine fever virus (asfv) specific, cytotoxic t lymphocyte (ctl) activity has been studied in a protection model in which sla inbred miniature swine are experimentally inoculated with a naturally occurring, non-fatal asfv isolate (nhv). peripheral blood mononuclear cells (pbmc) from such infected swine show significant activity in ctl assays, using cultured asfv-infected porcine blood derived macrophages as target cells. this ctl activity is elicited from pbmc by in vitro restimulation of ...	1993	8470951
sequence and characterization of the major early phosphoprotein p32 of african swine fever virus.	the gene encoding protein p32, the most abundant and immunogenic protein induced by african swine fever virus at early times of infection, has been mapped in the ecori c' fragment of the genome of the vero cell-adapted virus strain ba71v. sequencing analysis has shown the existence of an open reading frame, named c'204l, encoding 204 amino acids. the protein is phosphorylated in serine residues located in the 115 n-terminal amino acids and was phosphorylated when expressed in cells infected with ...	1993	8474154
cellular immune response to hog cholera virus (hcv): t cells of immune pigs proliferate in vitro upon stimulation with live hcv, but the e1 envelope glycoprotein is not a major t-cell antigen.	t-cell responses of pigs to hog cholera virus (hcv) have reportedly been absent or difficult to detect. therefore, little is known about cellular immunity to hcv. in this study, we used an attenuated strain of pseudorabies virus expressing the envelope glycoprotein e1 of hcv and purified recombinant e1 to examine whether the e1 protein is a target antigen recognized by the t cells of hcv-immune pigs. we were unable to identify the e1 protein as a major target antigen recognized by the t cells of ...	1993	8474180
characterization of two african swine fever virus 220-kda proteins: a precursor of the major structural protein p150 and an oligomer of phosphoprotein p32.	two kinds of unrelated african swine fever virus proteins of 220 kda have been identified by means of two-dimensional gel electrophoresis and immunoprecipitation analysis. one species, named pp220 and identified as the precursor of the major structural protein p150, was found to be a moderately acidic protein (pl near 7) expressed after the replication of the viral dna. the second species, a cluster of 220-kda proteins with slightly different isoelectric points (pl ranging from 5 to 6), was foun ...	1993	8480423
prophylactic application of propionibacterium avidum kp-40 in swine with acute experimental infections. i. viral infections--aujeszky's disease and classical swine fever.	the usefulness of the prophylactic application of propionibacterium avidum kp-40 (pa), a potent stimulator of the macrophage-monocyte system and inducer of endogenous interferons, was demonstrated in swine infected experimentally with aujeszky's disease or classical swine fever viruses. some of the infected animals were preimmunized with respective vaccines containing live, attenuated viruses. in vaccinated and non-vaccinated swine infected with aujeszky's disease virus, pretreatment with pa low ...	1993	8486091
structure and expression in e. coli of the gene coding for protein p10 of african swine fever virus.	the gene encoding protein p10, a structural protein of african swine fever (asf) virus, has been mapped, sequenced and expressed in e. coli. protein p10 was purified from dissociated virus by reverse-phase hplc, and its nh2-terminal end identified by automated edman degradation. to map the gene encoding protein p10, a mixture of 20-mer oligonucleotides based upon a part of the amino acid sequence was hybridized to cloned asf virus restriction fragments. this allowed the localization of the gene ...	1993	8503790
african swine fever virus encodes two genes which share significant homology with the two largest subunits of dna-dependent rna polymerases.	a random sequencing strategy applied to two large sali restriction fragments (sb and sd) of the african swine fever virus (asfv) genome revealed that they might encode proteins similar to the two largest rna polymerase subunits of eukaryotes, poxviruses and escherichia coli. after further mapping by dot-blot hybridization, two large open reading frames (orfs) were completely sequenced. the first orf (np1450l) encodes a protein of 1450 amino acids with extensive similarity to the largest subunit ...	1993	8506138
application of a blocking enzyme-linked immunosorbent assay for serological monitoring of hog cholera (classical swine fever) in poland.	between 1990 and 1992, serum samples from 55,478 domestic swine were tested by enzyme-linked immunosorbent assay (elisa) for the presence of hog cholera virus (hcv) antibodies. the amount of antibody in the sera was expressed as the mean percentage inhibition (pi). for diagnosis, the tested sera were diluted 1:2 and considered positive if the pi was less than 25%. sera giving pi values in the range of 25-50% were retested against hcv and bovine virus diarrhoea virus (bvdv), by neutralising perox ...	1993	8219338
virus-host interactions in african swine fever: the attachment to cellular receptors.	biochemical and morphological techniques have shown that african swine fever virus (asfv) enters susceptible cells by a mechanism of receptor-mediated endocytosis. the virus binds to a specific, saturable site in the cell and this interaction is required for a productive infection. a structural asfv protein of 12kda (p12) has been identified to be involved in the recognition of the cellular receptor, on the basis of the specific binding of the polypeptide to sensitive vero cells. protein p12 is ...	1993	8219802
african swine fever virus genome content and variability.	a 55 kilobase pair (kb) region from the right end of the virulent african swine fever virus isolate, malawi lil20/1, has been sequenced. the 68 major open reading frames (orfs) encoded are generally closely spaced and read from both dna strands across the complete sequence. comparison of the amino acid sequences of predicted orfs with sequence databases identified 15 orfs which encode proteins that are similar to proteins of known function. two orfs are homologous to copies of multigene family 3 ...	1993	8219803
molecular characterization of positive-strand rna viruses: pestiviruses and the porcine reproductive and respiratory syndrome virus (prrsv).	molecular characterization has become an important tool for the analysis of viruses including their classification. the manuscript focuses on the molecular analysis of two members of the genus pestivirus (hog cholera virus, hcv and bovine viral diarrhea virus, bvdv) and of the recently discovered porcine reproductive and respiratory syndrome virus (prrsv). the first protein encoded within the single large pestivirus orf is a nonstructural protein with autoproteolytic activity. the cleavage site ...	1993	8219812
the relative density of cd44-positive porcine monocytic cell populations varies between isolations and upon culture and influences susceptibility to infection by african swine fever virus.	african swine fever (asf) virus has been reported to infect cells of the monocyte family, probably macrophage-like cells, but there is variation in the apparent susceptibility of these cells. we have demonstrated that the phenotype and activity of porcine monocytic cells varies between different isolations and also upon culture. the variation during culture is dependent upon the phenotype of the cells at the time of isolation. as for the susceptibility of porcine monocytes/macrophages to infecti ...	1993	8225410
processing of pestivirus polyprotein: cleavage site between autoprotease and nucleocapsid protein of classical swine fever virus.	the polyprotein of classical swine fever virus starts with the nonstructural protein p23, which is followed by the nucleocapsid protein p14. proteolytic cleavage between p23 and p14 was demonstrated in a cell-free transcription-translation system. successive truncation of the cdna used for the transcription indicated that the proteolytic activity responsible for the cleavage between p23 and p14 resides within p23. in order to determine the cleavage site between these two proteins, the respective ...	1993	8230432
african swine fever virus interaction with microtubules.	the role of microtubules in intracellular transport of african swine fever virus (asfv) and virus-induced inclusions was studied by immunofluorescence using anti-asfv and anti-tubulin antibodies, by electron microscopy of infected vero cells and by in vitro binding of virions to purified microtubules. mtc, a reversible colchicine analogue, was used to depolymerize microtubules. in cells treated with mtc multiple large inclusions containing asfv antigens and particles were observed in the cytopla ...	1993	8241964
mapping and sequence of the gene encoding the african swine fever virion protein of m(r) 11500.	the gene encoding the african swine fever virus protein of m(r) 11,500, present in the virus particle, has been mapped and sequenced in the genome of the vero cell-adapted virus strain ba71v. a serum raised against virion proteins of m(r) 12,000 to 13,000 isolated from polyacrylamide gels was used to screen a plasmid expression library, containing viral dna random fragments, that expresses viral polypeptides fused to beta-galactosidase. using this method, we have identified and sequenced the ope ...	1993	8245848
african swine fever virus encodes a cd2 homolog responsible for the adhesion of erythrocytes to infected cells.	we have identified an open reading frame, ep402r, within the ecori e' fragment of the african swine fever virus genome that encodes a polypeptide of 402 amino acid residues homologous to the adhesion receptor of t cells, cd2. transcription of ep402r takes place during the late phase of virus replication. the disruption of ep402r, achieved through the replacement of a 354-bp-long fragment from within ep402r by the marker gene lacz, does not affect the virus growth rate in vitro but abrogates the ...	1993	8102411
[clinical and anatomo-pathological differences in 2 strains of african swine fever virus in angola].	african swine fever (asf) is prevalent in angola. it is caused by several strains of viruses, among which silva-porto and huambo 85. a clinical and anatomo-pathological comparative test carried out on the natural and experimental disease showed different and significant characteristics in the behaviour of these two strains. silva-porto generates clinical signs characterized by an haemorrhagic generalized diathesis more marked on the skin, organs and viscera. in addition, the anatomo-pathological ...	1993	8073167
localization of the african swine fever virus attachment protein p12 in the virus particle by immunoelectron microscopy.	the african swine fever virus attachment protein p12 was localized in the virion by immunoelectron microscopy. purified virus particles were incubated, before or after different treatments, with p12-specific monoclonal antibody 24bb7 and labeled with protein a-colloidal gold. untreated virus particles showed labeling only in lateral protrusions that followed the external virus envelope. mild treatment of african swine fever virions with the nonionic detergent octyl-glucoside or with ethanol onto ...	1993	7679861
reverse interference method for measurement of hog cholera virus (hcv) and anti-hcv antibody.	a new procedure was developed for the assay of the hog cholera virus (hcv) and anti-hcv antibody. initially, the suppression effect of hcv on interferon (ifn) by hcv production was confirmed. swine kidney cell cultures preinfected with hcv produced no ifn, even following the addition of ifn inducers. however the sensitivity of the cell to ifn was not influenced by the infection with this virus. based on these results, a new method, named reverse interference method, was established. in this meth ...	1993	7685639
characterization of structural and non-structural proteins of hog cholera virus by means of monoclonal antibodies.	a panel of 15 monoclonal antibodies, produced against the hog cholera virus, were characterized by radioimmunoprecipitation assays. using this panel, we were able to identify 4 sets of monoclonal antibodies precipitating each a different viral protein with relative molecular weight of 40, 46, 120 kda, respectively, and a protein complex containing 15, 16, 27, and 55 kda polypeptides which were further characterized. one monoclonal antibody recognized an antigenic determinant at the c-terminal cl ...	1993	7688508
virulent african swine fever virus isolates are neutralized by swine immune serum and by monoclonal antibodies recognizing a 72-kda viral protein.	convalescent swine serum to african swine fever virus (asfv) isolate e75 neutralized the infectivity of virulent asfv isolates e75, e70, lisbon 60, malawi lil 20/1 and a low passage tissue culture adapted variant of e75, e75cv/v3, by 86-97% in vero and macrophage cell cultures. a monoclonal antibody, mab-135d4, recognizing an asfv protein of 72 kda also exhibited strong neutralizing activity with these viruses. unexpectedly, both e75 immune sera and mab-135d4 failed to neutralize high passage ti ...	1993	7690502
epitope mapping of envelope glycoprotein e1 of hog cholera virus strain brescia.	four antigenic domains (a, b, c and d) on envelope glycoprotein e1 (gp51-54) of hog cholera virus strain brescia have been specified by using 13 monoclonal antibodies (mabs) that recognize non-conserved and conserved epitopes. it was shown that the non-conserved epitopes map to the n-terminal half of e1 by analysis of chimeric e1 proteins of strains brescia and c. conserved epitopes, however, could not be mapped using this approach. here we describe mapping of both conserved and non-conserved ep ...	1993	7691986
a preliminary map of epitopes on envelope glycoprotein e1 of hcv strain brescia.	monoclonal antibodies (mabs) directed against envelope glycoprotein e1 (gp51-54) of hog cholera virus (hcv) strain brescia have been shown to recognize four different antigenic domains a, b, c and d. epitopes of within domain a have mainly been found conserved among hcv strains, whereas epitopes within domains b, c and d are not conserved. we used transiently expressed hybrid e1 genes of hcv strains brescia and "c" to map the non-conserved epitopes on e1. epitopes in domains b and c are located ...	1992	1282755
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
heterogeneous expression of the non-structural protein p80/p125 in cells infected with different pestiviruses.	in order to analyse the expression of the non-structural (ns) protein p80/p125 in cells infected with different pestiviruses at the protein level, radioimmunoprecipitations with the pestivirus-specific monoclonal antibody (mab) bvd/c16 were performed. cell lysates infected with cytopathic (cp) and non-cytopathic (ncp) bovine viral diarrhoea (bvd) virus strains and isolates, and with hog cholera (hc) virus strains were analysed. from cpbvd virus-infected cells, the mab precipitated one or more pr ...	1992	1309861
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
the pestiviruses.		1992	1315479
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
protection of piglets born from ruminant pestivirus experimentally infected sows, and their contacts, to the challenge with hog cholera virus.	two groups, a and b, of two specific pathogen-free pregnant sows were experimentally infected between the 25th and 29th days post-breeding with two strains of ruminant pestivirus: nadl cytopathic bovine viral diarrhoea virus for group a and aveyron non-cytopathic border disease virus french strain for group b. two other pregnant sows (group c) were kept uninoculated as control. when 7 weeks old, 8 piglets of group c were put in contact with 4 piglets of group a (group d), and 8 other piglets of ...	1992	1324630
the hog cholera virus.	hog cholera virus (hcv) is a spherical enveloped particle of about 40-60 nm dia. the viral genome is a single strand rna of about 12,000 bases with positive polarity. one single large open reading frame codes for presumably four structural, i.e. three glycoproteins and a core protein, and about three to five nonstructural proteins. the functional role is not yet fully clear for all viral proteins. hcv belongs to the pestivirus group and it is closely related to bovine viral diarrhoea and border ...	1992	1325334
hog cholera diagnostic techniques.	clinical signs and lesions can sometimes provide the basis for a presumptive diagnosis of hog cholera (hc). however, an accurate diagnosis requires laboratory testing. the usual procedure for the detection of viral antigen is the examination of cryostat sections stained with fluorescein-conjugated hc antiserum. a more definitive technique is isolation of the virus in pk-15 cell cultures and identification of the viral antigen in cells using an hc fluorescent antibody conjugate. as bovine viral d ...	1992	1325335
african swine fever virus encodes a gene with extensive homology to type ii dna topoisomerases.	nucleotide sequencing of a virulent african swine fever virus (asfv) isolate (malawi lil20/1) identified an open reading frame of 1191 amino acid residues encoding a protein of 134.9 kda. this gene mapped to the sali i and j restriction endonuclease fragments of the asfv genome. the predicted polypeptide was found to share 21.1% identity over a 1077 amino acid region with the human type ii dna topoisomerase. the sequence is compared to other type ii dna topoisomerases and the possible roles in a ...	1992	1335084
thermal and ph stability of pestiviruses.	three strains/isolates of hog cholera virus (hcv) and two strains/isolates each of cytopathogenic (cp) and non-cytopathogenic (ncp) biotype of bovine virus diarrhoea virus (bvdv) were each exposed to ph 3, 3.5 and 4 at 4 degrees c, 21 degrees c and 37 degrees c in a number of combinations. infectivity titration and half-life determinations following correlation and regression analysis showed a significant temperature-dependent shortening of half-lives within the ph range investigated. at ph 3, m ...	1992	1335310
analysis of t lymphocyte subsets proliferating in response to infective and uv-inactivated african swine fever viruses.	the proliferative response to infective and uv-inactivated african swine fever virus was analyzed in cells from pigs surviving an experimental infection with attenuated virus. all the pigs showed strong dose-dependent proliferative responses to both infective and uv-inactivated virus. this response was also observed when nitrocellulose-bound solubilized virus proteins were used in the assay. heterologous isolates also induced proliferation, however it was significantly lower than that induced by ...	1992	1362304
flow cytometric analysis of african swine fever virus-induced plasma membrane proteins and their humoral immune response in infected pigs.	african swine fever (asf) virus-induced plasma membrane proteins may contribute to the protective immune response against the disease since they can be involved in the antibody-mediated lysis of infected cells. in this study we describe the regulation of asf virus-induced plasma membrane protein expression and its antibody induction in pigs after viral infection by flow cytometric analysis. more than 80% of infected cells contained viral antigens on the surface membranes at 6 hr postinfection (h ...	1992	1376539
characterization and pathogenicity for pigs of a hog cholera virus strain isolated from wild boars.	one hog cholera virus strain isolated from an outbreak of the disease in a wild boar breeding herd in brittany (france) in 1990 has been characterized with a panel of monoclonal antibodies to hog cholera virus and ruminant pestiviruses: the strain was found to be indistinguishable from that of other domestic pig isolates. the pathogenicity of the strain to domestic pigs was evaluated by infecting intranasally, intramuscularly and by contact 17 specific pathogen-free 6-week- and 12-week-old pigs. ...	1992	1387299
african swine fever virus infection in the iberian soft tick, ornithodoros (pavlovskyella) marocanus (acari: argasidae).	one thousand six hundred ornithodoros (pavlovskyella) marocanus velu larvae were fed on a pig infected with african swine fever virus (titer: 10(7.4) had50/ml), and 1,600 larvae were fed on an uninfected pig. ticks in each group were compared for mortality rates, mean time to death for ticks that died, mean time from feeding to either molting or eclosion, percentage of ticks that eclosed or molted, and the number of blood meals per nymph or instar. cumulative virus-induced mortality for all imma ...	1992	1404269
transcriptional analysis of multigene family 110 of african swine fever virus.	a transcriptional analysis of the 3.2-kb region of the african swine fever virus genome containing the five members of the multigene family 110 is presented. the mrnas corresponding to the genes studied have short leader sequences with no intervening aug codons before the translational start site, and their 3' ends map within a conserved sequence motif formed by a stretch of seven or more consecutive thymidylate residues. the possible role of this sequence as a signal for the 3'-end formation of ...	1992	1404609
african swine fever virus-induced dna polymerase is resistant to aphidicolin.	african swine fever virus (asfv) induces the synthesis of a virus-specific dna polymerase, which is inhibited by phosphonoacetic acid and cytosine arabinoside. in contrast to all other alpha-like dna polymerases of dna viruses, asfv-specific dna polymerase is resistant to aphidicolin. concentrations of the drug as high as 160 microm had no effect on virus production or plaquing efficiency. the resistance of asfv dna polymerase to aphidicolin was confirmed by analyzing the effect of the drug on v ...	1992	1413523
distribution of asfv antigens in pig tissues experimentally infected with two different spanish virus isolates.	lymph nodes, spleen, liver, lung and kidney obtained from pigs experimentally infected with two african swine fever virus (asfv) isolates of differing virulence were fixed by perfusion with glutaraldehyde and embedded in paraffin. an immunoperoxidase technique using a polyclonal anti-asfv serum was performed on tissue sections in order to detect asfv antigen. the distribution of asfv antigen in such infected organs is shown and the differences between both infections compared and discussed. mono ...	1992	1414093
localization of african swine fever viral antigen, swine igm, igg and c1q in lung and liver tissues of experimentally infected pigs.	an immunohistological study was carried out on lungs and livers of pigs experimentally infected with two different african swine fever virus (asfv) isolates. asfv antigen, swine immunoglobulins (igm and igg) and (clq) complement were demonstrated in both organs at different stages of infection. the asfv antigen was mainly found in mononuclear phagocytic system (mps) cells. immunoglobulins and complement were observed in plasma, infected and non-infected phagocytic cells and cell debris. these fi ...	1992	1430349
molecular characterisation of a dna ligase gene of the extremely thermophilic archaeon desulfurolobus ambivalens shows close phylogenetic relationship to eukaryotic ligases.	a 3382 bp fragment containing a gene for a dna ligase from the extremely thermophilic, acidophilic, and facultatively anaerobic archaeon (archaebacterium) desulfurolobus ambivalens was cloned and sequenced. the deduced amino acid sequence (600 amino acids, 67619 molecular weight) showed 30-34% sequence identity with the atp-dependent eucaryal (eukaryotic) dna ligases of schizosaccharomyces pombe, saccharomyces cerevisiae, the human dna ligase i, and with the vaccinia dna ligase. distant similari ...	1992	1437556
[polypeptides p14 and p31 of the african swine fever virus--early proteins located on the membrane of the infected cell].	african swine fever virus polypeptides p14 and p31 are synthesized in the presence of phosphonacetic acid which inhibits viral dna replication, and therefore they are early viral proteins. these polypeptides were found to be localized on plasma membranes by immunofluorescence with monospecific antisera and monoclonal antibodies and by selective solubilization of infected cells. the p14-specific antibodies mediate complement-dependent cytolysis and antibody-dependent cytotoxicity of the cells inf ...	1992	1441444
[immune reactions to the african swine fever virus].	host immune reactions to african swine fever virus variants differing in their virulence were studied comparatively. their obvious variabilities in antibody induction to some polypeptides active in antibody-dependent cell cytotoxicity and cytotoxic t-lymphocytes were demonstrated. t-helpers of immune pig splenocytes were found to recognize the cells infected with avirulent but not virulent virus variants. the described differences were not connected with the changes in sla-1 antigen expression i ...	1992	1441445
a comparison of the pathogenicity of two strains of hog cholera virus. 1. clinical and pathological studies.	the virulence of a strain of hog cholera virus isolated during an outbreak of mild disease in pigs in new south wales in 1960/61 (the nsw strain) was compared over 11 days with that of a virulent strain by inoculating 8 pigs with each virus and comparing the ensuing clinical signs and pathology. both viruses caused persistent pyrexia and leukopenia, the nsw strain 4 to 5 days and the virulent strain 3 days, after inoculation. few other clinical signs were observed in the pigs inoculated with the ...	1992	1445070
a comparison of the pathogenicity of two strains of hog cholera virus. 2. virological studies.	quantitative and qualitative differences were demonstrated in the amount of virus in a range of tissues from pigs infected with either the weybridge or new south wales (nsw) strains of hog cholera (hc) virus. the titre of the weybridge strain in samples, as assessed by either virus titration in cell culture or by the density of specific fluorescing cells in tissue sections, was higher than that for the nsw strain. this correlated with the greater severity of the clinico-pathological syndrome ind ...	1992	1445071
evaluation of the complex trapping blocking-elisa in a serological survey during the belgian classical swine fever epizootic in 1990.		1992	1455586
african swine fever virus infection in the soft tick, ornithodoros (alectorobius) puertoricensis (acari: argasidae).	in total, 1,186 second instar ornithodoros (alectorobius) puertoricensis fox second instars were fed on a pig when it had a viremia of 10(5.2) hemadsorption units (had50/ml) and 420 second-instar o. puertoricensis were fed on an uninfected pig. subsequent blood meals for ticks in both groups were from uninfected pigs. the effects of african swine fever virus (asfv) infection on o. puertoricensis populations were evaluated for the following parameters: mortality; mean time to death; percentage mo ...	1992	1460641
survival of hog cholera virus (hcv) in sausage meat products (italian salami).	survival of hog cholera virus (hcv) was determined in several sausage meat products (italian salami) prepared with meats from experimentally infected hogs slaughtered at the peak of disease. meats were processed following the technology applied by the main factories of the typical italian production. the survival of hcv was assessed through inoculation in both pk 15 cell monolayers and fully susceptible piglets. in all types of sausages examined hcv was detected up to 75 days of curing by piglet ...	1992	1476864
approaches to the identification of non-essential genes of african swine fever virus.	it is poorly understood why vaccines could not be developed for the control and prevention of african swine fever (asf) virus infection. the aim of our study was to identify genes non-essential for asf virus replication because there were indications that certain viral gene products, which apparently are non-essential for viral replication, conferred protection from death due to asf. a cosmid library representing the genome of asf virus strain france 64 was established and characterized. then, i ...	1992	1481351
analyses of the primary in vitro responsiveness of non-immune porcine peripheral blood mononuclear cells with reference to immunization by african swine fever virus antigen and treatment with leucine methyl ester.	peripheral blood mononuclear cells (pbmc) from non-immune pigs were immunized in vitro using african swine fever (asf) virus antigen with concomitant mitogenic stimulations known to have varying effects on b and t lymphocyte activity. none of these conditions, including those previously reported as being successful for the in vitro immunization of non-immune porcine pbmc with asf virus antigen, supported the induction of specific antibody. due to the reports on in vitro immunization of human pbm ...	1992	1487303
experimental transmission of african swine fever virus by the soft tick ornithodoros (pavlovskyella) marocanus (acari: ixodoidea: argasidae).	a total of 1,600 ornithodoros (pavlovskyella) marcocanus larvae were fed on a pig with a viremia of 10(7.4) had50/ml of african swine fever virus (asfv). infected larvae were sampled daily for 15 d, and nymphs were sampled at least once per instar until they became adults. initial titers of 10(4.48) had50 per larva declined to 10(4.04) within 2 d. larval titers reached a maximum of 10(6.0) had50 per larva 10 d after the infective blood meal. nymphs of each instar were fed on a susceptible pig an ...	1992	1495075
detection of african swine fever viral antigens in paraffin-embedded tissues by use of immunohistologic methods and polyclonal antibodies.	tissues obtained from pigs inoculated with african swine fever virus (asfv), fixed by vascular perfusion using glutaraldehyde, and embedded in paraffin or araldite were used for an immunohistologic electron microscopic study. to detect asfv antigens, 4 methods were used on paraffin sections with or without pretreatment of the tissues. use of biotinylated anti-asfv antiserum combined with avidin-biotin complex and peroxidase proved to be the most suitable method, and antigen was detected in tissu ...	1992	1510327
a sensitive dot immunobinding assay for serodiagnosis of african swine fever virus with application in field conditions.	the present work describes a simple dot immunobinding assay (dia) for african swine fever virus (asfv) antibody detection that can be used under field conditions. the assay uses nitrocellulose strips dotted with a cytoplasmic soluble antigen (cs-p) of asfv. the nitrocellulose strips are adhered to a plastic handle. the test serum samples react with the cs-p, and antibodies are detected using a protein a-peroxidase conjugate. both incubations are carried out at 20 c. the efficacy of the dia as a ...	1992	1515486
a review on classical swine fever infections in pigs: epizootiology, clinical disease and pathology.	a review is given on classical swine fever (csf) including epizootiology, clinical disease and pathology. under the item of epizootiology the history of csf is briefly summarized. ways of transmission are described with special reference to csf in wild boars. the chapter about clinical disease includes the description of different courses of csf such as peracute, acute, subacute form and chronic disease with reference to the course of transplacental infection and fate of the progeny associated w ...	1992	1516362
a tissue culture vaccine with lapinized chinese (lc) strain of hog cholera virus (hcv).	the lapinized chinese (lc) strain of hog cholera virus (hcv), was adapted to grow in a cell line from minipig kidney (mpk) where it reached a titer, as determined by immunofluorescence, significantly higher than in rabbits. inasmuch as the immune serum to hcv neutralized the culture-adapted virus, it was concluded that its antigenicity did not undergo any change after adaptation to mpk cells. the mpk-lc adapted virus (mpk-lc-hcv) showed also a higher immunogenic activity in rabbits, in compariso ...	1992	1516363
expression in vivo and in vitro of the major structural protein (vp73) of african swine fever virus.	the vp73 protein was produced by in vitro transcription and translation from the xho i-bam hi fragment located between the cla i-n and cla i-h fragments of the viral genome. this dna fragment encodes a late mrna of about 2.6 kb detected in infected ms monkey and bhk hamster cells. the transcript was initiated at a site within two bases upstream of the translation initiation codon. the in vitro synthesized polypeptide shows the same molecular weight as the in vivo synthesized polypeptide, suggest ...	1992	1550491
modulation of splenic macrophages, and swine leukocyte antigen (sla) and viral antigen expression following african swine fever virus (asfv) inoculation.	expression of viral and major histocompatibility complex (mhc) antigens and localization of t cells and macrophages was studied in frozen tissue sections of spleens taken from normal pigs or from pigs inoculated with highly virulent lisbon 60 (l60), or with moderately virulent dominican republic 1978 (dr-ii), african swine fever virus (asfv) isolates. splenic sections from l60 inoculated pigs exhibited a large decrease in macrophage staining, whereas dr-ii infected animals appeared more intensel ...	1992	1550493
african swine fever virus: generation of subpopulations with altered immunogenicity and virulence following passage in cell cultures.	virus subpopulations with variable virulence, immunogenicity, and infectivity to pigs were readily generated by passaging tengani isolate of african swine fever virus, either biologically cloned or uncloned, in vero cell cultures. avirulent virus populations which account for more than 99% of virus in an uncloned preparation of the 27th passage are laboratory artefacts, perhaps do not exist in nature. furthermore, attenuation of virulence did not occur uniformly in all subpopulations newly gener ...	1992	1558888
[light and electron microscopic findings in the intestine of spontaneous and experimentally-produced african swine fever].	light and electron microscopical studies were carried out after experimental induced and spontaneous infection with african swine fever virus. the experimental infection was performed in 18 pigs divided into two groups consisting of 9 animals. the pigs of group i were inoculated with virulent isolate e 70, those of group ii with attenuated isolate e 75. two infected pigs of group i and one control animal were killed on days 3, 5 or 7 p.i., two pigs of group ii and one control animal were killed ...	1992	1559460
genetic manipulation of african swine fever virus: construction of recombinant viruses expressing the beta-galactosidase gene.	homologous recombination is shown to be specifically induced in vero cells by infection with african swine fever (asf) virus. the frequency of recombination induced by asf virus infection between cotransfecting plasmids is comparable to that found after infection with the prototype poxvirus, vaccinia virus. the induction of recombination is accompanied by replication of the plasmid templates in the asf virus-infected cells. an asf virus insertion/expression plasmid vector containing the escheric ...	1992	1566585
[is feeding of green silage in areas with hog cholera in wild boar a danger for domestic swine herds? experimental study].	in an experimental study we tested the survival of hog cholera virus (hcv) contained in pieces of muscular tissue and organs from experimentally infected swine after incubation in silage. in big (diameter greater than 20 cm) muscular pieces hcv survived even in excellent mineral acid silage (ph 3.8-4.0) after a storage of 5 months. on the other hand in smaller parts (musculature tissue, organs less than 20 cm diameter) we never found virulent hcv after 3 months of incubation. independent of the ...	1992	1575668