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neutralization kinetics studies with type sat 2 foot-and-mouth disease virus strains.a comparison of homologous and heterologous rates of neutralization demonstrated that antigenic relationships of foot-and-mouth disease virus strains could be differentiated quantitatively by the kinetics of neutralization method described previously (rwysed this way gave r values which were similar to those obtained with other neutralization test methods but which were generally smaller than those obtained with complement fixation test results. it was demonstrated that there were wide differenc ...197768071
cultivation of foot and mouth disease virus in bovine leukocyte cultures for use in the complement fixation test.bovine leukocyte cultures achieved good growth after 72 hours of cultivation. foot-and mouth disease (fmd) virus type 0 multiplied in such cultures to a titre of 10(6) tcid50/0.1 ml. the cell culture-grown virus was found to be suitable for the complement fixation test (cft) after purification and concentration with calcium phosphate.19769808
[complement fixation micromethod for determining the type of foot-and-mouth disease virus]. 1975163522
[setting up a neutralization reaction for the foot-and-mouth disease virus]. 1975163521
cell-free translation of foot-and-mouth disease virus rna into identifiable non-capsid and capsid proteins.foot-and-mouth disease virus (a member of the picornavirus group) rna could be translated effectively in an s-30 extract from ehrlich ascites tumour cells. this translation was inhibited by aurintricarboxylic acid, cycloheximide, puromycin and rnase. cell-free products of translation were identified by disc gel electrophoresis and immunoprecipitation with specific antisera. gel electrophoresis of the products without prior immunoprecipitation suggested the synthesis of some of the non-capsid pro ...197661250
structure of foot-and-mouth disease virus capsid. 197938568
[effect of the ph of the medium on the morphology of bp cell cultures and their sensitivity to the foot-and-mouth disease virus]. 197934920
[cultivation of the foot-and-mouth disease virus in continuosly inoculated cells of piglet kidney]. 1975163519
resolution of block neutralization test curves into components of the foot-and-mouth disease virus system.classic neutralization studies by fazekas de st. groth and webster (8) on mixtures of influenza viruses and mixtures of rabbit antisera are reinterpreted in terms of a percentage contaminant in the stock used for the dilution series. a very small amount of a different virus changes the shape of quantal assay curves considerably, but even a large amount of a different antiserum has negligible effect on the shape and merely shifts the curve along the serum dilution axis. these conclusions are the ...197992300
[effect of the contrast conditions using solutions of phosphotungstic acid on the electron microscopic image of the foot-and-mouth disease virus].a method of negative staining of foot-and-mouth disease virus preparations permits to obtain separately positive (2% phosphotungstic acid solution, ph 3.0) and negative (2% pta solution, ph 6.8 +/- 8.0) stainings. when a 3--4% pta solution, ph 6.8 +/- 8.0 is used, simultaneous positive and negative staining of each virion is possible which characterizes the functional heterogeneity of the virion protein membrane in interaction with pta anions.197992099
[production of purified foot-and-mouth disease virus antigens and the specific sera against them].it was demonstrated that the use of laboratory techniques could be contributive to the production of purified antigens of the f.m.d. virus, such a-140 s, 12 s, and via. the isolated purified antigens were used to immunize guinea pigs, obtaining specific antisera against them. it was found that the latter contained specific complement-fixing and precipitating antibodies, while the 140 s serum also had neutralizing antibodies. the produced 140 s serum contained certain amounts of 12 s antibodies, ...197885363
effect of trypsin and chymotrypsin on the polypeptides of large and small plaque variants of foot-and-mouth disease virus: relationship to specific antigenicity and infectivity.large and small plaque variants of a12 foot-and-mouth disease virus were shown to have specific antigenic determinants. large plaque virus antigenic specificity was destroyed by trypsin treatment, but the small plaque antigen was resistant despite cleavage of the trypsin-sensitive polypeptide. the cleavage of polypeptide vp3 by trypsin resulted in the formation of a new antigen not present on untreated virus. the effects of chymotrypsin and trypsin on the polypeptides of the plaque variants have ...197884854
some investigations on the adjuvant mechanism of deae dextran.in vitro it was shown that adsorption of inactivated fmdv onto deae-d kieselgur columns did not occur in the presence of 0.1--0.15m nacl. these nacl concentrations are present in deae-d/fmdv vaccines and in the tissues of animals. therefore, adsorption of virus antigen does not appear to be responsible for the adjuvant effect of deae-d. in pigs it was demonstrated that deae-d exerts its optimal adjuvant effect, as measured by the formation of neutralizing antibodies and protection against challe ...1975164161
antibody response against foot and mouth disease virus (fmdv). part ii: responses measured in fractionated sera of infected steers with complete virus, trypsin treated virus, 12 s virus subunits, via and heterologous virus. 197993833
the use of the haemagglutination-inhibition test for detecting antibodies to type sat 2 foot-and-mouth disease viruses in cattle sera.two strains of type sat 2-foot-and-mouth disease virus which gave high titres of haemagglutinin activity reacted type-specifically in direct haemagglutination-inhibition tests with reference, bovine convalescent antisera. comparisons of the haemagglutination-inhibition and the serum neutralization tests using cattle sera showed that both were equally specific and sensitive for detecting virus antibody.1975163274
[several criteria of evaluation of foot-and-mouth disease virus reproduced in cell cultures in suspension].the study of the plaques produced by viruses asia and o1 reveals different properties which may depend on the virus or on the cell or its method of culture. antigenic differences and subsequent immunological differences correspond to differences in plaques. on the other hand, the cell line in suspension evolves both in its morphology and its receptivity during the passages. all these variations imply the observations of quantitative and qualitative criteria of evaluation in order to prepare vacc ...197671255
comparison of the antibodies elicited by the individual structural polypeptides of foot-and mouth disease and polio viruses.antibody produced against preparations of vp1, one of the four structural polypeptides of foot-and-mouth disease virus, neutralized the virus and reacted with both full and empty particles in radioimmunoassays (ria). antiserum against vp2 reacted with artificial empty particles of the virus but not with full particles. in contrast, none of the individual polypeptides of poliovirus produced antisera which neutralized the virus nor reacted with it in ria. however, antisera produced with vp1 and vp ...197994352
comparative biochemical and serological analysis of five isolates of a single serotype of foot-and-mouth disease virus.a comparison has been made of some of the biochemical and serological characteristics of five isolates of foot-and-mouth disease virus (fmdv), serotype a. three of the viruses have been assigned to the same subtype, a22; the other two belong to different subtypes, a5 and a24. rna competition hybridization and two-dimensional electrophoresis of the oligonucleotides produced by ribonuclease t1 showed that the three a22 viruses formed a group which could be distinguished from the a5 and a24 viruses ...197994348
pre-lytic release of foot-and-mouth disease virus in cytoplasmic blebs.the pre-lytic release mechanism of foot-and-mouth disease virus was investigated by immunofluorescence, acridine orange staining, and electron microscopy in infected bovine and porcine kidney coverslip cultures. cells with cytoplasmic fluorescence and which were positive for single stranded rna with acridine orange staining were observed at 2 h after infection. scanning electron microscopy showed cytoplasmic blebs in all cultures examined 2 h after infection. rounded cells with virus inclusions ...197881266
effect of methyl glyoxal on infectivity and antigenicity of foot-and-mouth disease virus.the inactivating effect of methyl glyoxal on foot-and-mouth disease (fmd) virus was studied. the rate of inactivation depended upon the drug concentration, incubation temperature and ph of the medium. rna recovered from the inactivated virus was not infectious. the complement-fixing activity of the virus was not reduced by methyl glyoxal treatment. the antigenicity of inactivated virus preparations determined by levels of virus neutralizing antibody in the blood sera of immunized white rats and ...197611665
physico-chemical properties of swine vesicular disease virus.titration of svdv on primary pig kidney cell cultures revealed a plating efficiency of less than or equal to 0,9 x 10(-3). concentration and purification of the svd-virus propagated on pig kidney cell cultures were done by chloroform treatment, adsorption, differential- and density gradient centrifugation. the following physical parameters were found: svdv is an isometrical rna-virus having a diameter of 25,1 +/- 1,0 nm. it is resistent to the action of chloroform, ether and ph. the virus has a ...197610872
further studies of the physical and metabolic properties of foot-and-mouth disease virus temperature-sensitive mutants.three temperature-sensitive (ts) mutants of foot-and-mouth disease virus were classified as ribonucleic acid negative and as belonging to the same complementation group when measured by virus yields and 3h uridine incorporation in paired, mixed infections at the nonpermissive temperature (38.5c). mutant ts-22, the only mutant able to produce plaques at 38.5 c, was more sensitive to acid than were the parental wild-type or other mutant viruses. diethylaminoethyl-dextran did not enhance the plaque ...19765377
[antigenic structures of the foot-and-mouth disease virus]. 197667699
neutralization kinetics studies with type sat2 foot-and-mouth disease virus strains. 1. factors that influence the rate and pattern of neutralization.a study of the kinetics of inactivation of foot-and-mouth disease virus type sat 2 strains revealed that in most cases the rate of neutralization was not rectilinear. deviations from first-order kinetics observed represented biphasic or parabolic and stepwise reactions. the initial rate was rapid and showed no lag phase or shoulder. the effects of deviations from linearity could be minimized by dilution of antiserum to a suitable extent. treatment of virus-antibody mixtures with anti-species glo ...197713123
demonstration of trypsin-sensitive antigenic determinants common to the intact virus particle and the 12s subunit of the uga 6/70 strain of foot-and-mouth disease virus type sat 2. 197767182
[types and subtypes of foot-and-mouth disease virus and their practical significance]. 197776365
a comparison of some immunological methods for the differentiation of strains of foot-and-mouth disease virus.two fmdv strains which had been previously differentiated by complement-fixation were compared by guinea-pig protection test, kinetic neutralization and micro-neutralization tests. it was found that these tests, which have not been previously applied by the methods described, were all capable of fmdv strain differentiation. similar differences were found by all methods, which suggests that comparisons made by cross-cf, cross-neutralization or cross-protection involve measurement of the same anti ...1975164500
effect of trypsin treatment on the antigenic characteristics of plaque variants of type-o 1 and type asia-1 foot-and-mouth disease viruses.antigenic differences were demonstrated between the large and small plaque variants of both types o1 and asia-1 foot-and-mouth disease viruses. treatment of the large and small plaque variants of the viruses with trypsin essentially abolished the observed antigenic differences. thus, these plaque variants have antigenically different trypsin-sensitive determinants that may influence their immunogenicity and infection capabilities.197882610
proteins induced in bhk cells by infection with foot-and-mouth desease virus.although the infection of bhk cells with foot-and-mouth disease virus did not cause a marked inhibition of cellular protein synthesis, the proteins synthesized gradually changed from host-specific to virus-specific. the synthesis of at least thirteen virus-induced proteins was demonstrated by polyacrylamide electrophoretic analysis of the infected cells. only a small proportion of the virus-induced proteins was incorporated into the mature virus particles. the addition of amino acid analogues ca ...1975164515
the sub-type classification of strains of foot-and-mouth disease virus.sixteen foot-and-mouth disease virus (fmdv) strains of type sat 1 were compared in complement-fixation tests. with the test used, the range of antigenic variation within a type appeared to be greater than previously described. the concept of a sub-type group within which all strains are more closely related to each other than to any strain outside the group was not supported. considering the group of strains studied, it is suggested that the classification of strains is best achieved by moninati ...1975164501
a genetic recombination map of foot-and-mouth disease virus.sixty ts mutants were isolated from the pacheco strain of type o foot-and-mouth disease virus after treatment with either 5-fluorouracil or hydroxylamine. the conditions affecting recombination and assay of the ts+ recombinants were standardized. using two ts mutants resistant to guanidine, three-factor crosses, supported by two-factor crosses, located 34 of the mutations in a linear arrangement. the recombination frequencies between certain pairs of mutations were additive. the guanidine charac ...1975167118
persistence of foot-and-mouth disease virus in butter and butter oil. 197827543
studies with foot-and-mouth disease virus in british deer (muntjac and sika). clinical disease, recovery of virus and serological response. 1975167058
production, isolation, and partial characterization of three foot-and-mouth disease virus temperature-sensitive mutants.three high temperature-sensitive (ts) mutants of foot-and-mouth disease virus were characterized by their relative abilities to grow at 33 or 38.5 c, to kill infant mice, to infect guinea pigs, and to produce foot-and-mouth disease in steers. mutants ts-24 and ts-42 did not grow at 38.5 c; both may have produced considerable quantities of noninfectious virus particles at 33 c. a third mutant, ts-22, appeared "leaky" because it multiplied to a limited extent during prolonged incubation at the non ...1975166915
the effect of acetylethyleneimine upon a strain of inactivated foot-and-mouth disease virus stored at 4 degrees c.the presence of either thiosulphate-neutralized or free aei was shown to degrade inactivated foot-and-mouth disease virus type o (hong kong) antigen during storage at 4 degrees c. deterioration was evident after 20 weeks of storage and little antigen remained at 36 weeks. optimum stability was obtained by removing the residual inactivant immediately after inactivation.1975166627
[influence of varying storage temperatures on the infectivity and antigenicity of foot-and-mouth disease virus strains before and after inactivation]. 1975166530
effect of pasteurization and evaporation on foot-and-mouth disease virus in whole milk from infected cows.the effects of pasteurization and evaporation on foot-and-mouth disease virus in whole milk from infected cows obtained one day postinoculation were studied. virus survived the heating of milk at high temperature-short time pasteurization at 75 degrees c for 15-17 seconds. in addition, virus from infected milk survived heating at 80 degrees c for the same time. infective virus also survived in the pasteurized milk after evaporation at 65 degrees c to 50% of the original volume. the bovine udder ...1975166740
the pathogenicity of bovine strains of foot and mouth disease virus for impala and wildebeest.impala (aepyceros melampus) and wildebeest (connochaetes taurinus) were infected with bovine strains of foot and mouth disease virus by intradermolingual inoculation. no clinical signs developed in the impala but mild atypical lesions developed in the tongues of the wildebeest with generalized spread to one foot in two of the eight animals exposed. all the impala but only some of the wildebeest developed viraemia. no virus could be isolated from any tissues in either species after the 7th day fo ...1975167208
removal of acetylethyleneimine from suspensions of inactivated foot-and-mouth disease virus. 1975166252
induction of neutralizing antibodies and immunity in vaccinated guinea pigs by cyanogen bromide-peptides of vp3 of foot-and-mouth disease virus.the specificity of guinea pig antisera against large cyanogen bromide-cleaved peptides of the virus capsid protein vp3 of foot-and-mouth disease virus type o1, strain kaufbeuren has been characterized by double immunodiffusion, virus neutralization and protection tests. antibodies to purified 146s particles and the cleavage peptides of vp3 showed an incomplete cross-section against vp3 peptide antigen when reacted in immunodiffusion tests, indicating that new antigenic determinants are exhibited ...197765445
binary ethylenimine as an inactivant for foot-and-mouth disease virus and its application for vaccine production.foot-and-mouth disease virus was inactivated with binary ethylenimine formed apart from or directly in the virus suspension by the cyclization of 2-bromoethylamine hydrobromide or 2-chloroethylamine hydrochloride under alkaline conditions. the inactivation rates with binary ethylenimine prepared apart from the virus suspension in dilute sodium hydroxide with either 2-bromoethylamine hydrobromide or 2-chlorethylamine hydrochloride were higher than with pure ethylenimine. when binary ethylenime wa ...1975167679
cross-reactions of normal bovine serums to foot-and-mouth disease virus in plaque-reduction neutralization and radial immunodiffusion.serums from 150 cattle with no known exposure to foot-and-mouth disease (fmd) virus were tested by both the plaque-reduction neutralization (prn) technique and the radial immunodiffusion (rid) technique to evaluate the significance and the extent of cross-reactions in these tests. serums from 30 cattle from each of 5 locations were tested against representative viruses of each of the 7 types of fmd virus. high levels of cross-reactions with both the rid and prn techniques were found in serums of ...1975167625
virulence of temperature-sensitive mutants of foot-and-mouth disease virus.a number of temperature-sensitive mutants isolated from two strains of foot-and-mouth disease virus were examined for their virulence in suckling mice. the majority of the mutants were found to be less virulent than the parent virus strains, ranging from slight to total attenuation, but two mutants retained parental levels of virulence. there was no correlation between mutant cut-off temperatures and virulence, or the revertant content of mutant preparations and virulence. it was not always poss ...1975167681
[discovery of the foot-and-mouth disease virus]. 1975171130
[studies on the influence of the host system on the result of the neutralization of monodispersed and untreated foot- and mouth disease virus (author's transl)].monodispersed foot- and mouth disease virus was obtained by filtration through membranes having a porosity only twice the diameter of the virus. this monodispersed virus was neutralized by immune sera in the same manner as not treated virus. this was shown by the inactivation curve comparing the amount of virus used for the test (calculated as id50) with the neutralization titre (nd50) or comparing the reduction of infectivity (also calculated as id50) with the dilution factor of the antiserum. ...1975169651
influence of serum restriction on foot-and-mouth disease virus infections in cell cultures. i. enhanced viral susceptibility. 1975169654
influence of serum restriction on foot-and-mouth disease virus infections in cell cultures. ii. altered viral replication. 1975169655
[electron microscopy demonstration of fibrillar structures in the foot-and-mouth disease virus].purified fmd virus was heat treated and then examined by electron microscopy with the negative contrast technique. fibrils of varying length and thickness were present; they were not present after ribonuclease treatment. they were similar to the fibrils described for other picornaviruses. viral rna was the essential component of these artificially arranged fibrils, which were composed of threads about 10 a wide, separated from one another by a gap of about 10 a.1975173250
[structure of the foot-and-mouth disease virus. 2. various physical and chemical properties of the 12s components].the 12s units were purified by heat treatment and acidification of purified, highly-concentrated virus, with separation of viral rna by gel filtration. the following physical parameters were obtained: - partial specific volume 0.737 +/- 0.020 g/cm3; diffusion soefficient d020,w = 3.96 +/- 0.24 f; sedimentation coefficient s020,w = 12.1 +/- 0.5s; molecular weight 283,00 +/- 30,000 dalton; refraction increment (determined by ultracentrifugation) was dn/dc = 0.189 +/- 0.010 cm3/g for white light of ...1975173253
variation among strains of type a foot-and-mouth disease virus in the eastern mediterranean region 1964-1972.variants of type a fmd virus from the eastern mediterranean region over the years 1964-72 have been shown to belong to a group distinct from the western european strains as represented by a5 westerwald. this group appears to derive from the a22 strain first recognized in 1964 and indicates the possibility of new strains supplanting old in the field.1975172558
n-terminal amino acid sequences in the major capsid proteins of foot-and-mouth disease virus types a, o, and c.sequences of amino acids at the n-termini of virus proteins vp1, vp2, and vp3 were determined for foot-and-mouth disease virus types a12 strain 119, o1brugge and c3resende. in the polyacrylamide gel electrophoresis system used to purify the proteins, vp3 migrated faster than vp1 or vp2; and in the virion, vp3 could be cleaved by trypsin into vp3a and vp3b. the n-terminal amino acids for each of the virus types were glycine in vp1, aspartic acid in vp2, and threonine in vp3. no divergences in seq ...1975171452
[resistance of vaccinated animals to heterologous subtypes of the foot-and-mouth disease virus]. 1976176768
the production of foot-and-mouth disease virus from bhk 21 c 13 cells grown on the surface of glass spheres.in view of the advantages which are associated with the use of the bhk monolayer cell for the production of foot-and-mouth disease (fmd) virus, a unit system using glass spheres was developed to grow bhk monolayer cells and to test the susceptibility of such cells to fmd virus. the yield of cells and their susceptibility compares favorably with green bhk monolayer cells which have been grown in roux bottles.1976179634
foot-and-mouth disease virus rna. presence of 3'-terminal polyriboadenylic acid and absence of amino acid binding ability. 1976176778
[sensitivity of cells of the transplanted sheep kidney line to foot-and-mouth disease virus]. 1975174273
[determination of the subtype membership of the epizootic foot-and-mouth disease virus by means of the agar gel diffusion test].comparative studies were carried out by means of the agar gel-diffusion technique (agdt) to establish the antigenic identity between the epizootic foot-and-mouth disease strain (the nch/73 representative strain) and the standard viruses of type a. the epizootic strain was found to belong to the subtype group a5. discussed is the usefulness of agdt in determining the antigenic relations between the foot-and-mouth disease viruses.1975174281
[cytological characteristics of a bovine kidney cell culture chronically infected with foot-and-mouth disease virus (author's transl)].a virus-carrier state was observed in the process of subcultivation of foot-and-mouth disease virus-infected calf kidney cell culture. cytologically, the chronically infected culture differed from the control culture by the presence of a large number of syncytial cells which did not die in acute infection because of poor susceptibility to the virus. chronic infection appeared to be maintained by occasionaly polygonal cells which retained the initial sesceptiblity to foot-and-mouth disease virus. ...1975174327
[immunobiological properties of strains of foot-and-mouth disease virus multiplying in cell cultures]. 1975174272
the production of foot-and-mouth disease virus from bhk 21 c 13 cells grown on the surface of deae sephadex a50 beads.methods are described which make possible the production of foot-and-mouth disease (fmd) virus from bhk 21 c13 monolayer cells which have been grown on the surface of serum coated deae sephadex a50 beads. the yield of cells and their susceptibility to infection by fmd virus are equivalent to conventional roux monolayer systems. the potential for the commercial application of the deae sephadex a50 system is discussed in relation to other unit process monolayer systems and in particular to the sys ...1976179635
immune and antibody responses to an isolated capsid protein of foot-and-mouth disease virus.the purified capsid proteins vp1, vp2, and vp3 of foot-and-mouth disease virus type a12 strain 119 emulsified with incomplete freund's adjuvant were studied in swine and guinea pigs. swine inoculated on days 0, 28, and 60 with 100-mug doses of vp3 were protected by day 82 against exposure to infected swine. serums from animals inoculated with vp3 contained viral precipitating and neutralizing antibodies, but such serums recognized fewer viral antigenic determinants than did antiviral serums. cap ...1975171309
survival of foot-and-mouth disease virus in cheese.persistence of foot-and-mouth disease virus during the manufacture of cheddar, mozzarella, camembert cheese prepared from milk of cows experimentally infected with the virus was studied. cheese samples were made on a laboratory scale with commercial lactic acid starter cultures and the microbial protease marzyme as a coagulant. milk was heated at different temperatures for different intervals before it was made into cheese. food-and-mouth disease virus survived the acidic conditions of cheddar a ...1976184130
[electron microscopy studies on the proliferation of foot-and-mouth disease virus in cell cultures. ii. changes in nucleic acid metabolism of the cell nucleus].bhk cells were infected with fmd virus and treated with tritium-labelled thymidine and uridine for examination by autoradiography under the electron microscope. labelling of the dna, examined by autoradiography under the optical microscope, showed inhibition of 3h-thymidine incorporation. for demonstrating rna labelling of nuclei, some cells were treated with actinomycin d and others were left untreated. under the lectron microscope there was no evidence of increased 3h-uridine incorporation in ...1975172042
growth of foot-and-mouth disease virus in the upper respiratory tract of non-immunized, vaccinated, and recovered cattle after intranasal inoculation.non-immunized, vaccinated, and recovered cattle were inoculated intranasally with various doses of foot-and-mouth disease virus. samples of oesophageal-pharyngeal (op) fluid were taken periodically for up to 7 days after inoculation and virus titres of these samples were plotted as pharyngeal virus growth curves. in non-immunized cattle, the length of the lag period and of the growth period were inversely proportional to the dose of virus given. maximum titres were observed when clinical signs w ...1976180177
[electron microscopy studies on proliferation of foot-and-mouth disease virus in cell cultures. i. morphologic changes in cell nucleus].the first morphological indication of fmd infection of a cell culture was in the nucleus. components of nucleoli became segregated and were finally present only as remnants. it was not possible to distinguish different stages of segregation, as in the case of entero-virus infections, because of the rapidity of fmd virus proliferation. following changes in nucleoli there was margination of chromatin. particularly striking was an increase in interchromatin granules. changes in the nuclear membrane ...1975172041
[electron microscopy studies on the proliferation of foot-and-mouth disease virus in cell cultures. iii. morphogenesis in cytoplasm].the previous parts have been concerned with the participation of the cell nucleus in the formation of the rna of fmd virus. however, the actual morphogenesis of the virus takes place in cytoplasm. in bhk cells, changes attributable to virus infection were visible by the second hour, with the formation of threads and large polysome complexes near the nucleus. viral particles soon appeared between these structures. there were no pronounced foci of viroplasma, and it seemed that they were not neces ...1975172043
[study of the indirect complement fixation test for use in the differentiation of foot-and-mouth disease viruses and the determination of immunity].studies were carried out to establish the optimal conditions for the indirect complement-fixation test (icft) and explore the possibility to use the test in differentiating the foot-and-mouth disease (fmd) viruses and checking the immunity obtained in survivals or in animals that had been vaccinated against fmd. it was demonstrated that the proper use of icft necessitates in turn the use of a minimal amount of antigen, which in the presence of 1-2 e homologous hyperimmune serum completely binds ...1975179191
experimental placental transfer of foot-and-mouth disease virus in mice.an attenuated type o foot-and-mouth disease (fmd) virus which was virulent for infant, but not for pregnant, mice proved to be superior to a virulent type c fmd virus in the development of a model system for the study of placental transfer of fmd in mice. when mice were inoculated at day 8 or 12 of gestation with type o fmd virus, the virus was detectable in the maternal pancreas for 3 days and in the placenta for 6 days. viral levels in the fetus and the amniotic fluid were inconsistent and wer ...1976179452
[production of highly active hyperimmune sera against the foot-and-mouth disease virus]. 1975175551
[persistence of the foot-and-mouth disease virus in experimentally infected jackdaws]. 1975175553
[effectiveness of a regime for the pasteurization of milk contaminated with the foot-and-mouth disease virus]. 1975175542
[new cell lines and the adaptation of the foot-and-mouth disease virus to them]. 1975175552
the survival of foot-and-mouth disease virus in open air conditions.the influence of the open air factor (oaf) and daylight on the survival of foot-and-mouth disease (fmd) virus held as captured aerosols on spider microthreads has been investigated. virus inactivation due to oaf was slight. similarly, the effect of daylight on the survival of virus was not marked. the results are discussed in relation to the airborne spread of fmd virus in nature.1975168250
a comparison of molecular weights of foot-and-mouth disease virus rna fragments determined from lengths and s-rates.a comparison was made of the calculated mol. wt. of rna fragments from foot-and-mouth disease virus (fmdv) types a12 strain 119, c3 resende and o1 brugge. the mol. wt. were calculated by two methods: from the measurements of strand lengths in the electron micrographs and from the observed sedimentation rates (s-rates). rna extracted from virus by dialysis against water usually had three to four prominent strands of different lengths. mol. wt. calculated from s-rates (and converted to strand leng ...1976177721
inhibitors of foot-and-mouth disease virus. temperature-dependence of the effect of guanidine on virus growth.in suspended secondary calf kidney cells infected with foot-and-mouth disease virus (fmdv) the temperature range for optimal virus growth is shifted down by 3 to 5 degrees c in the presence of 1--2 mm guanidine. for some virus strains this shift is so effective that at infraoptimal temperatures virus yield in guanidine-treated cells exceeds that of the corresponding control by more than one log10. on the contrary, at supraoptimal temperatures inhibition of virus growth by the drug is strongly en ...1976187151
characterization of the minor polypeptides in the foot-and-mouth disease particle.in addition to the four major polypeptides vp1 and vp4, foot-and-mouth disease virus particles contain two minor polypeptides, mol. wt. 40 x 10(3) (p40) and 52 x 10(3) (p52). extensive purification procedures failed to remove these minor polypeptides from the virus particles. polypeptide p40 co-electrophoresed in sds-polyacrylamide gels with vp0, the probable precursor of vp2 and vp4 and was inaccessible to iodination in situ. the second minor polypeptide, p52, co-electrophoresed with the virus ...1976177728
a major difference in the strategy of the calici- and picornaviruses and its significance in classification.pig kidney (1brs-2) cells infected with vesicular exanthema virus (vev), a calicivirus, did not contain any large precursor polypeptides similar to those found when they were infected with foot-and-mouth disease virus (fmdv). the largest induced protein found in the vev-infected cells had a molecular weight identical with that of the virus structural polypeptide. this difference in strategy between vev and fmdv, taken in conjunction with the morphological and structural differences described pre ...1975178628
evidence for recombination between two different immunological types of foot-and-mouth disease virus.recombination was observed between temperature-sensitive (ts) mutants of two immunological types of foot-and-mouth disease virus which were distinguishable by two marker characteristics in addition to their antigenic type. putative ts+ recombinants were isolated and the segregation patterns of their marker characteristics examined. the results are discussed in terms of the origin of new sub-type strains.1975180948
[comparative serological study of the principal strains of the foot and mouth disease virus isolated in ethiopia 1969-1974]. 1975181797
effect of heat on foot-and-mouth disease virus (fmdv) in the components of milk from fmdv-infected cows.foot-and-mouth disease virus (fmdv) survived in skim milk, cream and the pelleted cellular debris components of milk obtained from fmdv-infected cows after pasteurization at 72 degrees c for 0-25 min. virus was recovered from whole milk of infected cows after that milk was heated at 72 degrees c. for 5 min. and from the skim milk component after it was heated at the same temperature for 2 min. evaporation of the whole milk samples after they were heated at 72 degrees c. for 3 min. did not inacti ...1976185284
pathogenesis of foot-and-mouth disease: clearance of the virus from the circulation of cattle and goats during experimental viraemia.viraemia is an important aspect of the pathogenesis of infectious diseases, but the mechanisms of entry and removal of virus from the vascular system particularly in natural hosts are poorly understood. the results of this study showed that the clearance of foot and mouth disease virus (fmdv) from the circulation of cattle and goats followed the general rules for the clearance of inert particulate materials and other viruses from the circulation. high doses of infused fmdv were cleared less effi ...1976185289
use of cell cultures with persistent virus infections to test the efficacy of antiviral compounds.bhk-21 cells persistently infected with either vaccinia or foot and mouth disease virus were used to study the efficacy of antiviral compounds. the results of the persistent infection cell culture (picc) test were compared with those obtained by the plaque reduction (pr) test. the comparison showed that: (1) the picc test is more informative than the pr test; (2) stimulative as well as inhibitory activities of compounds are detectable, and (3) since the picc test can be carried on for several we ...1976182439
unified mass-action theory for virus neutralization and radioimmunology.all ideas implicit in the papers since 1953 involved in applying mass-action thermodynamics to antibody-antigen reactions are unified by the use of: (a) the intermediary concept of extent of reaction; (b) the concept of intrinsic association constant; (c) a statistical analysis for probable complexes; and (d) identification of the complex or complexes that contribute to the bioassay. several general theoretical examples are given that show the limitations of linear interpretations of equilibrium ...1976185688
[foot and mouth disease virus]. 1975185664
[role of antibodies in the antigenic variability of the foot-and-mouth disease virus]. 1976186935
susceptibility of a new fetal pig kidney cell line (mvpk-1) to foot-and-mouth disease virus.the mengeling-vaughn porcine kidney (mvpk-1) cell line, derived in october, 1970, from fetal pig kidneys, is susceptible to all 7 types of foot-and-mouth disease (fmd) virus. a plaque assay was developed for fmd virus that depended on washing mvpk-1 cells in serum-free medium before infection and excluding serum from 0.6% gum tragacanth overlay during plaque formation. the numbers of plaques that formed on mvpk-1 cells by a representative strain of each fmd type were comparable with the numbers ...1976185927
[electrophoretic studies of foot-and-mouth disease virus subtypes a1-a5 from various sources using carrier-free zone electrophoresis in a glucose density gradient]. 1976183418
[structure of foot-and-mouth disease virus]. 1976183422
[some modern data on the antigenic makeup of the foot-and-mouth disease virus and their practical significance]. 1976183347
[local interferon production in cattle after intranasal infection with avirulent ibr/ipv virus and its effect on a subsequent infection with foot-and-mouth disease virus]. 1976183421
[cultivation of the foot-and-mouth disease virus in various vnk-21 cell sublines]. 1976189481
[use of indirect complement fixation test for studying foot and mouth disease virus].the indirect complement-fixation test was used in experiments for the subtype differentiation, and with the agar gel diffusion and the serum neutralization test was studied the immunity in cattle that had already recovered from foot-and-mouth disease or were immunized against the disease. it was found that the indirect complement-fixation test is instrumental in the demonstration of the antigenic differences between the foot-and-mouth viruses. comparative experiments have shown that the indirect ...1976189484
[attempts to adapt bnk cells to cultivation in suspension and study of the antigenic properties of foot-and-mouth diseases viruses obtained from them].experiments were carried out to cultivate the foot-and-mouth disease virus under laboratory conditions in a suspension of the bhk-21 cell line. results showed that the number of cells cultivated in a susfor 48 to 72 hours of incubation reaches up to 2.2 x 10(6). it was also found that certain conditions should be observed for the successful cultivation of the cells in suspension, such as aeration, ph, and respective temperature. it was demonstrated that foot-and-mouth diseases viruses obtained f ...1976189487
susceptibility of the indian squirrel to foot-and-mouth disease virus. 1976183340
localisation on foot-and-mouth disease virus (fmdv) of an antigenic deficiency induced by passage in bhk cells.passage of fmdv in bhk suspended cells was confirmed to induce an antigenic deficiency on the virion. by immunodiffusion experiments with complete virus, with trypsin-treated virus and with 12s virus fraction it was shown that the induced antigenic deficiency is located on the trypsin-removable part of the virion. these results were confirmed by absorption experiments.1976184763
a foot-and-mouth disease vaccine for swine.an inactivated vaccine containing purified foot-and-mouth disease virus type o1, strain brugge, emulsified with incomplete freund's adjuvant was studied in swine. the antigen mass ranged from 0.02 to 416 mug in 0.25 ml of vaccine. at 90 days postinoculation (dpi) 33 to 100% of the swine which had been inoculated with 0.72% mug or larger amounts of antigen were protected against challenge. there was little protection at 182 dpi although the neutralizing titers obtained with 2.9, 34.6 and 416 mug ...1976187292
[comparison of the immunogenic potencies of purified inactivated foot-and-mouth disease virus particles with variable amounts of vp1 protein (author's transl)]. 1977195512
routine titration of foot and mouth disease virus suspensions by analytical ultracentrifugation. 1: sedimentation method.infectivity and complement fixation (cf) tests are commonly used for the routine titration of foot and mouth disease (fmd) virus suspensions. only recently were techniques published for the routine determination of the virus concentration by the physical properties of the virions (fayet et al., 1971; barteling et al., 1974). these techniques are based on the separation of the virions from the culture fluid by sedimentation through a sucrose gradient, in a preparative ultracentrifuge. the ultrav ...1976185978
determination of the time to harvest foot-and-mouth disease virus cultures by measurements of the supernatant concentration of lactic dehydrogenase. 1977195645
[cultivation of the foot-and-mouth disease virus on a monolayer of inoculable cells piglet kidney grown in vitro]. 1977195389
[foot-and-mouth disease in ethiopia. serologic and immunologic study of type a foot-and-mouth disease virus]. 1976189363
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