Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| 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 |
| 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 |
| 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 infection of pregnant goats with swine fever virus. | thirteen pregnant goats were inoculated intravenously with the ald strain of virulent swine fever (sf) virus on days 64-84 of gestation. dams showed transient and mild viremia, and produced high serum neutralizing (sn) antibody after inoculation. six inoculated dams were reared until parturition occurred and bore six apparently normal, one apparently normal but dead, one mummified and three edematous kids. neutralizing antibody was demonstrated in the pre-colostral sera obtained from all normal ... | 1989 | 2672548 |
| 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 |
| [molecular characterization of the hog cholera virus]. | the molecular biology of hog cholera virus (hcv) was studied. after reverse transcription of the viral rna the cdna was cloned in the expression vector lambda gt11. hcv clones were identified using antibodies as a probe. partial sequencing of one hcv-derived cdna clone revealed a high degree of homology to a portion of the bovine viral diarrhea virus (bvdv). one goal of these studies is the preparation of defined, effective and safe vaccines against pestiviruses. | 1989 | 2590156 |
| diversity of african swine fever virus. | an african swine fever virus is an heterogeneous population, consisting of clones having different biological characteristics in respect to hemadsorption, virulence, infectivity, plaque size, and antigenic determinants. the following observations were made: nonhemadsorbing virus (nhv) have been segregated from field isolates from haiti (ht-1) and a bone marrow- and buffy coat-passaged portuguese isolate (l'60bm89bc1) and appear as a major, minor, or equal mixture with hemadsorbing viruses in the ... | 1985 | 2581483 |
| antigenic differentiation of pestivirus strains with monoclonal antibodies against hog cholera virus. | thirty-one bovine viral diarrhoea virus (bvdv) or border disease virus (bdv) strains and 94 hog cholera virus (hcv) strains were grown in cell culture, and characterized by immunostaining with 13 monoclonal antibodies (mabs) and one polyclonal serum (pab) against hcv. all 125 strains were recognized by the pab. none of the bvdv or bdv strains were detected by the 13 mabs. seven mabs detected all 94 hcv strains. six other mabs detected heterogeneity among and within hcv strains. the mabs are usef ... | 1989 | 2560281 |
| general characteristics and viral susceptibility of a newborn pig kidney (npk) continuous culture. | we have developed a fibroblastic-like continuous culture of newborn pig kidney (npk). the current cell line was serially passaged 160 times and appeared to be well suited for production and assay of a number of viruses affecting pigs, such as pig parvovirus, pseudorabies and transmissible gastroenteritis. the cell line appeared aneuploid, with a modal chromosome number of 36 and induced tumors, classified as fibrosarcoma, in athymic mice. | 1989 | 2555655 |
| characterization of porcine and some ruminant pestiviruses by cross-neutralization. | serologic relationships between 11 pestivirus strains that originated from pigs and five that originated from cattle or sheep were studied by cross-neutralization. experiments were performed with pig and sheep sera raised against the strains. the results were analysed by a computerized taxonomic procedure. the 16 viruses were classified into four distinct serologic groups. all hog cholera virus (hcv) strains were classified in one group; the other three groups consisted of strains that can infec ... | 1989 | 2552645 |
| comparative analysis of monoclonal antibodies against pestiviruses: report of an international workshop. | thirty-three pestivirus strains were grown in cell culture and characterized by immunostaining with 19 monoclonal antibodies (mabs) raised against hog cholera virus (hcv), with 42 mabs against bovine viral diarrhoea virus (bvdv) and with 13 mabs against border disease virus (bdv). seven mabs reacted with all pestivirus strains tested, eight mabs detected only the seven hcv strains, three detected only the 16 bvdv strains. no mab was found that was specific for bdv. bvdv and bdv strains were broa ... | 1989 | 2549680 |
| hog cholera virus--characterization of specific antiserum and identification of cdna clones. | a specific antiserum was raised against the pestivirus inducing hog cholera (hog cholera virus, hcv). using immunoprecipitation and sds-page, this antiserum served for comparison of hcv-induced proteins with those from a related and better characterized pestivirus, bovine viral diarrhea virus (bvdv). in addition to immunological relationships, the apparent molecular weights of some proteins induced by both viruses were quite similar. hcv genomic rna was found to be about 12 kb in length, compara ... | 1989 | 2545029 |
| demonstration of bovine virus diarrhoea virus antigen in formalin fixed, paraffin embedded tissue using a streptavidin/biotin technique. | the detection of bovine virus diarrhoea virus (bvdv) antigen in sections from formalin fixed, paraffin embedded tissue is described. pre-digestion of the sections with 0.02 per cent protease xiv for 18 hours at 4 degrees c is necessary to unmask formalin fixed antigen. a hyperimmune antiserum prepared in a pig, using a combination of bvdv and hog cholera virus inoculations, linked to a biotinylated anti-pig/streptavidin peroxidase detection system demonstrated antigen in a wide range of tissues ... | 1989 | 2544973 |
| application of peroxidase labelled antibody assays for detection of porcine igg antibodies to hog cholera and bovine viral diarrhea viruses. | rapid, sensitive peroxidase labelled antibody (pla) assays using microtiter systems, were developed for detection of hog cholera virus (hcv) and cross-reacting bovine viral diarrhea virus (bvdv) antibodies in pig sera. hcv-infected pig kidney cell line (pk 15) prepared in microtiter plates were fixed and used in pla assays. after inoculation with test serum, bound antibodies (hcv/bvdv) were reacted with either horseradish peroxidase (hrp) conjugated anti-porcine immunoglobulin (h & l) or biotiny ... | 1989 | 2541152 |
| aetiology of kawasaki disease. | thirteen serum samples from nine children with kawasaki disease and 23 control samples gave negative results on screening for antibodies to hog cholera virus, border disease of sheep, bovine diarrhoea virus, and equine arteritis virus. the sera from two children with kawasaki disease were cytotoxic; a possible link with cytotoxin from propionibacterium acnes is considered. | 1989 | 2539788 |
| differentiation of hog cholera and bovine virus diarrhoea viruses in pigs using monoclonal antibodies. | monoclonal antibodies against hog cholera and bovine viral diarrhoea viruses were assayed on organ tissue sections of experimentally infected animals. the animals had been infected simultaneously with both viruses. the antibodies were tested using an indirect immunofluorescence test and an indirect enzyme immunoassay with a biotin/streptavidin/peroxidase detection system. a polyclonal hyperimmune serum was used as a control in direct immunofluorescence tests. both techniques based on monoclonal ... | 1989 | 2538980 |
| a survey of wild swine in the united states for evidence of hog cholera. | the results of surveillance for hog cholera (hc) in wild swine (sus scrofa) collected from throughout the united states from 1979 to 1987 are presented. sera collected from 1,218 wild swine and tissues from 637 were evaluated for hc antibodies and virus, respectively. included within this surveillance were samples from santa cruz and santa rosa islands, california, where hc virus had been deliberately introduced into wild swine during the 1950's in attempts to eradicate these animals. all evalua ... | 1989 | 2536850 |
| topographical and functional mapping of epitopes on hog cholera virus with monoclonal antibodies. | competitive binding studies and antigen capture assays were done with monoclonal antibodies (mabs) raised against hog cholera virus (hcv) to map the corresponding epitopes. a model was constructed in which the 13 epitopes were situated in four distinct antigenic domains: a, b, c and d. domain a was subdivided into a1, a2 and a3. the functional relevance of this model was assessed by the characterization of pestivirus strains, by neutralization studies with the mabs, and by isolation of variants ... | 1989 | 2479712 |
| high titre hog cholera virus production on cytodex 3 microcarrier cultures. | in an attempt to produce hog cholera virus (hcv) preparations of high titre, optimal growth and trypsinization conditions of pk-15 microcarrier cell cultures were defined. infecting a pk-15 cytodex 3 microcarrier culture with hcv increased the yield of virus more than 10 times compared with conventional monolayer culture in roux flasks. | 1989 | 2470336 |
| 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 |
| an enzyme immunoassay employing monoclonal antibodies and detecting specifically antibodies to classical swine fever virus. | an enzyme immunoassay (complex-trapping-blocking elisa, ctb elisa) for the detection of antibodies against classical swine fever virus (sfv) has been developed. the ctb elisa employs two monoclonal antibodies directed against different antigenic sites of sfv. a set of 2545 pig sera was tested in the ctb elisa and in the neutralizing peroxidase-linked assay (npla) for neutralizing antibody to sfv. the ctb elisa and the npla confirmed each other in 97% of the sera. the ctb elisa detects low-level ... | 1988 | 2459837 |
| 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 |
| [studies of the antigen structure of pestiviruses using monoclonal antibodies]. | 1987 | 2448112 | |
| production of monoclonal antibodies against swine fever virus and their use in laboratory diagnosis. | thirteen hybridoma cell lines which secrete monoclonal antibodies (mcas) against swine fever virus (sfv) strain brescia were produced. the hybrid cells resulted from fusion of p3x63-ag8.653 myeloma cells with splenocytes of balb/c mice which had been immunized with purified sfv. screening of supernatant fluids was performed by an indirect enzyme-linked immunosorbent assay (elisa) and an immunoperoxidase monolayer assay (ipma). the ipma, and an immunoperoxidase test (ipt) performed on cryostat se ... | 1986 | 2428160 |
| monoclonal antibodies of african swine fever virus: antigenic differences among field virus isolates and viruses passaged in cell culture. | an analysis of the binding properties of a collection of monoclonal antibodies to african swine fever virus particles showed that virus field isolates passaged in porcine macrophages changed antigenically more than a strain of a cell-adapted virus passaged in vero cells. from seven clones isolated from the spleen of a field-infected pig, we found four clones that had the same antigenic properties, one clone that had large changes in proteins p150 and p27 and small changes in proteins p37 and p14 ... | 1986 | 2422393 |
| nucleotide sequence of hog cholera virus rna: properties of the polyprotein encoded by the open reading frame spanning the viral genomic rna. | hog cholera virus rna was cloned and sequenced. a single major open reading frame (orf), encoding an amino acid sequence of 3898 residues, was found in the second reading frame of the sequence of one of the cdna strands. we demonstrated that the orf spans the length of the viral sense rna, which implies that it is translated into a precursor polyprotein. several properties of this polyprotein, like hydrophobicity, position of putative protease cleavage sites, distribution of n-linked glycosylati ... | 1990 | 2402871 |
| 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 |
| 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 |
| 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 |
| pestivirus glycoprotein which induces neutralizing antibodies forms part of a disulfide-linked heterodimer. | neutralizing monoclonal antibodies directed against hog cholera virus (hcv) precipitated two hcv-encoded glycoproteins, hcv gp55 and hcv gp33. immunoassay with bacterial fusion proteins and western immunoblotting with extracts from infected cells revealed that the antibodies recognized only hcv gp55. coprecipitation of hcv gp33 was shown to be due to intermolecular disulfide bridges. one of the antibodies also reacted with the major glycoprotein of another pestivirus, bovine viral diarrhea virus ... | 1990 | 2370675 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| immunoaffinity purification and characterization of the envelope protein e1 of hog cholera virus. | the envelope protein e1 of hog cholera virus (hcv) was isolated by immunoaffinity purification with monoclonal antibodies (mabs) directed against hcv. e1 consisted of a doublet of glycoproteins which varied in size from 51k to 56k between the three strains tested. e1 contains major antigenic determinants of hcv which are conserved, and are involved in neutralization by mabs. in infected cells, e1 was found always connected with a glycoprotein of 31k. when n-linked glycans were removed, e1 had a ... | 1990 | 2313266 |
| development and properties of a cell culture produced vaccine for hog cholera based on the chinese strain. | the chinese strain of hog cholera virus (hcv) was adapted to suspension cultures of the established swine kidney cell line sk6. the strain designated "cedipest", is produced on the basis of a seedlot system. the masterseed virus was identified in vitro and in vivo, and was found free from extraneous pig pathogenic viruses by repeated animal inoculation followed by appropriate serological tests. a distinct and reproducible relationship was ascertained between infectivity in vitro and protection. ... | 1990 | 2311534 |
| 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 |
| genomic localization of hog cholera virus glycoproteins. | a polyspecific antiserum has been used to identify four different glycoproteins in hog cholera virus (hcv)-infected cells termed gp55, gp48, gp44, and gp33 (rümenapf et al, 1989, virology 171, 18-27). fusion proteins containing parts of the putative hcv-encoded glycoproteins were expressed in bacteria and served for the preparation of specific antibodies. these were used in radioimmunoprecipitation assays which revealed that gp48 and gp44 most likely share a common protein backbone. the order of ... | 1990 | 2294643 |
| 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 |
| 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 |
| the lapinized chinese strain of hog cholera virus (hcv) previously adapted in minipig kidney (mpk) cell line cultures, would also protect pigs to experimental infection with virulent hcv [corrected]. | two-month old piglets previously inoculated with different dilutions of the lapinized chinese (lc) strain of hog cholera virus (hcv), adapted in a minipig kidney (mpk) cell line, resisted challenge infection with virulent hcv. all the animals remained healthy and the challenge virus was never recovered from any of them. in contrast, the pigs which served as controls for the challenging virus underwent the clinically lethal form of the disease and hcv was consistently recovered from their tissues ... | 1990 | 2273980 |
| 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 |
| 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 |
| 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 |
| [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 |
| 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 |
| 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 |
| 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 |
| a new approach for the diagnosis of hog cholera. | pestiviruses were isolated from seven cases of suspect hog cholera. using peroxidase conjugates of monoclonal antibodies (mabs) six isolates were identified as hog cholera viruses (hcv), while one isolate was of ruminant origin, possibly bovine viral diarrhea virus. in parallel attempts were made to develop an elisa for the detection of hcv-specific antibodies in pig sera. the mab hctc26 coated to polystyrol plates efficiently captured the major viral glycoprotein gp53 from crude antigen suspens ... | 1990 | 2178908 |
| antigenic comparisons of hog cholera virus isolates from europe, america and asia using monoclonal antibodies. | nineteen monoclonal antibodies (mabs) with specificity for hog cholera virus (hcv) were prepared. they were used in an immune binding (peroxidase linked) assay to determine the reaction patterns of hcv isolates from europe, brazil, usa, japan and malaysia, as well as laboratory reference strains of the virus. a further panel of 17 mabs raised against bovine virus diarrhoea virus (bvdv) was included in the study, together with 5 mabs raised against a non-hcv pestivirus of porcine origin. all the ... | 1990 | 2178905 |
| a blocking elisa to differentiate hog cholera virus antibodies in pig sera from those due to other pestiviruses. | the blocking elisa technique was extended to comparative serology by using 3 different pestivirus strains: hog cholera virus (hcv) alfort strain propagated in pk15 cell line, border disease virus (bdv) aveyron strain in pk15 and bvd nadl** strain in fetal calf kidney (fck) primary cells. rabbit antisera to the alfort hcv strain and aveyron bdv strain were raised for use in the test. a bovine hyperimmune serum to bvd virus was also used for detecting antibodies specific to bvd virus. the elisa wa ... | 1990 | 2163232 |
| molecular cloning and nucleotide sequence of hog cholera virus strain brescia and mapping of the genomic region encoding envelope protein e1. | genomic rna of hog cholera virus (hcv) strain brescia was cloned and sequenced. the nucleotide sequence was deduced from overlapping cdna clones and comprises 12,283 nucleotides. we cloned the complete 3' end of the hcv genome, but could not unequivocally prove that the cdna sequence also completely covers hcv rna at the 5' end. the hcv genome contained one large open reading frame, which spans the viral plus strand rna and encodes an amino acid sequence of 3898 residues with a calculated molecu ... | 1990 | 2162104 |
| hepatitis c virus shares amino acid sequence similarity with pestiviruses and flaviviruses as well as members of two plant virus supergroups. | hepatitis c virus (hcv) is an important human pathogen that is associated with transfusion-related non-a, non-b hepatitis. recently, hcv cdna was cloned and the nucleotide sequence of approximately three-quarters of the virus genome was determined. a region of the predicted polyprotein sequence was found to share similarity with a nonstructural protein encoded by dengue virus, a member of the flavivirus family. we report here that hcv shares an even greater degree of protein sequence similarity ... | 1990 | 2156259 |
| 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 |
| antibodies to some pathogenic agents in free-living wild species in tanzania. | a total of 535 sera from eight species of wildlife were collected from different game areas in tanzania between 1987 and 1989. these sera were tested for antibodies against foot-and-mouth disease, bovine herpes virus types 1 and 2, lumpy skin disease, bovine viral diarrhoea, akabane, bovine ephemeral fever, bluetongue, enzootic bovine leucosis, african horse sickness and african swine fever viruses and brucella abortus based on the expected species susceptibility. sera from buffalo syncerus caff ... | 1990 | 2123458 |
| 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 |
| in vivo study of hemadsorption in african swine fever virus infected cells. | 1991 | 2063520 | |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| structural proteins of hog cholera virus expressed by vaccinia virus: further characterization and induction of protective immunity. | a cdna fragment covering the genomic region that encodes the structural proteins of hog cholera virus (hcv) was inserted into the tk gene of vaccinia virus. expression studies with vaccinia virus/hcv recombinants led to identification of hcv-specific proteins. the putative hcv core protein p23 was demonstrated for the first time by using an antiserum against a bacterial fusion protein. the glycoproteins expressed by vaccinia virus/hcv recombinant migrated on sodium dodecyl sulfate-gels identical ... | 1991 | 1987372 |
| 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 |
| use of biotechnical methods in veterinary medicine. | biotechnological methods offer promising approaches for improved diagnostic and prophylactic purposes. the following biotechnological techniques are used in the institute of virology at the hanover veterinary school:--production of monoclonal antibodies directed against viral and bacteria-specific antigens such as bovine virus diarrhoea virus, classical swine fever (hog cholera) virus, feline leukaemia virus, animal parvoviruses, alphavirus, brucella and francisella--establishment of improved an ... | 1990 | 1966725 |
| bovine virus diarrhoea virus: speculation and observations on current concepts. | this final chapter highlights the advances and some of the unanswered questions concerning bovine virus diarrhoea virus (bvdv) presented in this review by specialists from around the world. persistently viraemic cattle play an essential role in the dissemination of bvdv but it is suggested that acute infections with the virus are also important. the role of latency is considered but, as yet, there is no evidence that it plays a part in pathogenesis. it is well established that bvdv, border disea ... | 1990 | 1966724 |
| ruminant pestivirus infection in pigs. | ruminant pestivirus infections of pigs have a worldwide distribution. the prevalence is varied and depends mainly on (i) contact with cattle, (ii) age of pigs and (iii) degree of homology of virus strains used for serology, with field strains of bovine virus diarrhoea virus (bvdv) infecting pigs. emphasis should be laid on sources of bvdv other than cattle, e.g. contaminated vaccines and fetal calf serum. the need for differentiation of pestiviruses (hog cholera, bovine virus diarrhoea and borde ... | 1990 | 1966720 |
| molecular biology of bovine virus diarrhoea virus. | our understanding of the molecular biology of bovine virus diarrhoea virus (bvdv) has greatly increased over the past several years. the development of monoclonal antibodies (mab's) has identified a key antigen of bvdv while at the same time providing evidence for considerable variation in this protein. mab's, particularly those directed against the p80 protein, can be developed for use in diagnostic tests while others may be useful in molecular epidemiological studies of bvdv. the successful cl ... | 1990 | 1966716 |
| 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 |
| hog cholera: an update of present knowledge. | 1991 | 1959010 | |
| 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 |
| protection tests in pigs vaccinated with the lapinized chinese strain of hog cholera virus (hcv) previously adapted in a minipig kidney (mpk) cell line, to challenge infection with virulent hcv. | pigs which had been vaccinated with the lapinized chinese strain of hog cholera virus previously adapted in a minipig cell line cultures (mpk-lc-hcv), resultet to be protected when they were subjected to challenge infection with virulent hog cholera virus (hcv) 6 or 11 months later. the challenge virus was never isolated from any of the vaccinated pigs. the mpk-lc-hcv vaccine induced a significant rise of the antibody titer to the hcv in pigs kept under field conditions. | 1991 | 1921741 |
| 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 |
| 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 |
| hog cholera virus: molecular composition of virions from a pestivirus. | virions from hog cholera virus (hcv), a member of the genus pestivirus, were analyzed by using specific antibodies. the nucleocapsid protein was found to be a 14-kda molecule (hcv p14). an equivalent protein could also be demonstrated for virions from another pestivirus, bovine viral diarrhea virus. the hcv envelope is composed of three glycoproteins, hcv gp44/48, gp33, and gp55. all three exist in the form of disulfide-linked dimers in virus-infected cells and in virions; hcv gp44/48 and gp55 e ... | 1991 | 1870198 |
| 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 |
| live attenuated pseudorabies virus expressing envelope glycoprotein e1 of hog cholera virus protects swine against both pseudorabies and hog cholera. | to investigate whether live attenuated pseudorabies virus (prv) can be used as a vaccine vector, prv recombinants that expressed envelope glycoprotein e1 of hog cholera virus (hcv) were generated. pigs inoculated with these recombinants developed high levels of neutralizing antibodies against prv and hcv and were protected against both pseudorabies and hog cholera (classical swine fever). | 1991 | 1850051 |
| 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 |
| rapid detection of hog cholera virus in tissues by the polymerase chain reaction. | a rapid method for the detection of hog cholera virus (hcv) in infected tissues, using polymerase chain reaction (pcr) was developed. total rna isolated from hcv-infected tissues was reverse transcribed with amv reverse transcriptase and the resulting complementary dna was amplified by taq dna polymerase in the presence of two hcv-specific primers. the amplified dna fragment was detected by agarose gel electrophoresis. the sensitivity of this method was at 10(4) tcid50 of hcv. the sensitivity in ... | 1991 | 1816255 |
| 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 |
| [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 |
| 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 |
| 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 |
| 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 |
| 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 |
| hybridoma antibody production in vitro in type ii serum-free medium using nutridoma-sp supplements. comparisons with in vivo methods. | six hybridoma clones (three producing anti-bovine viral diarrhoea antibodies and three producing anti-hog cholera virus antibodies) were studied with respect to their growth in type ii serum-free medium. this was found to be successful in all cases when the serum-free medium was supplemented with 1% v/v nutridoma, but only after adaptation over a small number of subcultures. adapted hybridoma cultures could be grown in 250 ml spinner flasks, and the antibody-containing supernatants concentrated ... | 1991 | 1765654 |
| 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 |
| 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 |
| [12 years control of hog cholera in the eec]. | 1992 | 1736411 | |
| 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 |
| 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 |
| pathogenesis of classical swine fever: b-lymphocyte deficiency caused by hog cholera virus. | hog cholera, also known as classical or european swine fever, is caused by hog cholera virus, a member of the genus pestivirus. it is shown here that the end stage of lethal infection in the natural host is associated with a dramatic depletion preferentially of b lymphocytes in the circulatory system as well as in lymphoid tissues. already at the onset of disease, viral replication in lymphoid tissues demarcates the germinal centers, and the viral genome remains localized to that site as the dis ... | 1992 | 1731095 |
| 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 |
| 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 |
| identification of conserved epitopes on a hog cholera virus protein. | eight monoclonal antibodies directed against the hog cholera virus (hcv) strain alfort/187 and displaying broad cross-reactivity with other hcv strains were characterized. an enzyme immunoassay on fixed monolayers of porcine or bovine cells infected with 14 different strains and isolates of hcv and 12 bovine viral diarrhea viruses (bvdv), respectively, showed that all antibodies reacted with hcv only. seven antibodies recognized all hcv tested, thus indicating that they were directed against con ... | 1990 | 1693844 |
| 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 |
| clinical, post mortem and virological findings after simultaneous inoculation of pigs with hog cholera and bovine viral diarrhoea virus. | the clinical course, post mortem lesions as well as virological and serological results after simultaneous intranasal inoculation of pigs with bovine viral diarrhoea virus (bvdv) and hog cholera virus (hcv) are described. five groups of four weaners received constant doses of bvdv strain osloss/2482 and tenfold decreasing doses of hcv strain alfort/187. doses of 1,000 and 100 tcid50 of hcv in groups a and b of pigs led to fever and severe clinical signs in all animals of two groups, whereas at h ... | 1991 | 1665632 |
| 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 |