Properties of maedi nucleic acid and the presence of ribonucleic acid- and deoxyribonucleic acid-dependent deoxyribonucleic acid polymerase in the virions.
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Maedi virus contains a ribonucleic acid (RNA) which can be resolved into three major components, namely, 62S, 33S, and 13S, by sucrose gradient centrifugation. The presence of RNA- and deoxyribonucleic acid (DNA)-dependent DNA polymerase in virions of maedi virus was demonstrated. The enzyme product could be converted into acid-soluble form by pancreatic deoxyribonuclease, but was resistant to digestion by pancreatic ribonuclease and to hydrolysis by NaOH. (+info)
Visualization by immune electron microscopy of a 27-nm particle associated with acute infectious nonbacterial gastroenteritis.
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A 27-nm particle was observed by immune electron microscopy in an infectious stool filtrate derived from an outbreak in Norwalk, Ohio, of acute infectious nonbacterial gastroenteritis. Both experimentally and naturally infected individuals developed serological evidence of infection; this along with other evidence suggested that the particle was the etiological agent of Norwalk gastroenteritis. (+info)
Distinct reovirus-like agents associated with acute infantile gastroenteritis.
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Human reovirus-like particles were found by electron microscopy in the stools of 25% of 71 infants and young children hospitalized with acute gastroenteritis in Mexico between December 1976 and April 1977. The virus was also identified by the electrophoresis patterns of its ribonucleic acid upon disruption of partially purified particles. This technique is as reliable as electron microscopy but less laborious, and could become a routine diagnostic procedure. The electrophoretic patterns of viral ribonucleic acid from different cases suggest that there are at least two different reovirus-like agents associated with infantile gastroenteritis. (+info)
Ultrastructural studies of a visna-like syncytia-producing virus from cattle with lymphocytosis.
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A virus structurally similar to viruses associated with maedi, progressive pneumonia, and visna of sheep has been isolated from buffy coat cells of cattle with chronic lymphocytosis. Electron microscope studies revealed three variants of the virion: (i) an intracytoplasmic form 98 to 116 nm in diameter when occurring in a nonlaminated form, (ii) a budding form 120 to 130 nm in diameter, and (iii) an extracellular form 80 to 130 nm in diameter and containing a 30 to 43 nm eccentrically located electron-dense core. (+info)
Immunological response to infection with human reovirus-like agent: measurement of anti-human reovirus-like agent immunoglobulin G and M levels by the method of enzyme-linked immunosorbent assay.
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The report describes the development of an enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies against the human reovirus-like agent of infantile gastroenteritis (HRVLA). This ELISA system proved to be four times as sensitive as the standard anti-HRVLA fluorescent-antibody assay and ten times as sensitive as the standard anti-HRVLA complement fixation assay. In addition, the ELISA was capable of determining immunoglobulin G (IgG) and IgM subclasses of anti-HRVLA antibody using a single dilution os serum. With this assay, it was discovered that 11 of 21 infected children had anti-HRVLA IgM in their acute sera before the appearance of anti-HRVLA IgG. ELISA is a useful tool in the evaluation of immunological response to HRVLA infection. (+info)
Studies on transmissible gastroenteritis of swine. 3. The effect of selective inhibitors of viral replication on a cytopathogenic virus from transmissible gastroenteritis.
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The effect on the plaque production of the Purdue strain of cytopathogenic virus from transmissible gastroenteritis of swine by 5-bromo-2'-deoxyuridine (BUDR), 5-iodo-2'-deoxyuridine (IUDR), actinomycin-D, puromycin, and amantadine-HCI (Symmetral) has been studied.Amantadine-HCI reduced the plaque-forming units of virus per ml by approximately 98%. Puromycin prevented almost all virus reproduction while actinomycin-D caused approximately a 22% reduction. Both IUDR and BUDR produced approximately a 20% increase in plaque-forming units of virus per ml. Swine testis cells stained with acridine orange early in the course of infection contained brick-red particles in the cytoplasm, indicative of a ribonucleic acid (RNA) type virus. (+info)
Biophysical and biochemical characterization of lymphocytic choriomeningitis virus. IV. Strain differences.
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Biological, biochemical, and biophysical properties of three lymphocytic choriomeningitis (LCM) virus strains were compared. The biological property examined was the concentration range of virus which would, when injected into neonates, cause a carrier state. The dosage range for the CA1371 and Traub strains was found to be as broad as the limits examined (5 to 100 ld(50) units/mouse). The WCP strain, however, would only produce carriers within a 3 to 5 ld(50) range. The biochemical properties examined were the growth rates in tissue culture and the effect of varying the input ratio of virus to cells. With identical input ratios, the Traub strain reached a peak titer 32 hr after infection. The CA1371 and WCP strain reached their peaks at the 40th hr. With a 10-fold decrease in the amount of CA1371 virus per cell, peak titer (as high as in the above experiments) was not obtained until 56 hr postinfection. The biophysical properties examined were stability in density gradients and inactivation rates at 4C. In potassium tartrate gradients, full recovery of the CA1371 and WCP strain could be achieved. However, inactivation kinetics showed that only the CA1371 strain was much more stable than the Traub-LCM. The realization that marked differences in LCM strains exist is discussed in relation to certain inconsistencies in the literature. (+info)
Transmissible gastroenteritis (TGE) of swine: canine serum antibodies against an associated virus.
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Sera of weaned puppies from a hysterectomy-derived, specific pathogen free (SPF) closed dog colony did not contain antibodies against a TGE-associated virus or a serologically related one, but sera from puppies and older dogs from open kennels did. The higher antiviral titers in serum of older dogs suggested that these animals had suffered either persistent or recurrent infections. Seventy-two puppies had no contact with swine, indicating that the virus was able to propagate independently of contact with swine. (+info)