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Biomedical subjects

C E Coto

Publications and source records attributed to C E Coto.

At least 73 records · Page 4Linked to original sources
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A comparison of Junin virus strains: growth characteristics, cytopathogenicity and viral polypeptides.

The growth characteristics, cytopathogenicity and viral polypeptides of the virulent strain XJ of Junin virus (JV), its attenuated derivative XJC13 and another naturally attenuated JV strain, IV4454, were comparatively studied. IV4454 and XJC13 viruses showed the highest and lowest cytopathology for Vero cells, respectively, as measured by plaque morphology, cell viability and inhibition of host cell protein synthesis. The kinetics and electrophoretic patterns of viral polypeptides in infected cell extracts were very similar among the three strains, whereas differences were detected in the surface glycoprotein GP38 by peptide mapping after limited proteolysis.

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PubMedDate not supplied

Cross-protection between Tacaribe complex viruses. Presence of neutralizing antibodies against Junin virus (Argentine hemorrhagic fever) in guinea pigs infected with Tacaribe virus.

Cross-protection between Junin virus and five other Tacaribe complex viruses and the serological response of guinea pigs inoculated with Tacaribe virus are reported here. Previous infection with Tamiami or Pichinde viruses significantly delayed guinea pig deaths. A 58% survival rate was found among animals immunized with three doses of Amapari virus, while guinea pigs inoculated with one dose of Machupo or Tacaribe virus were fully protected against Junin virus. Neutralization tests performed in serum samples of guinea pigs immunized with five doses of Tacaribe virus showed that they developed monologous and heterologous neutralizing antibodies.

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PubMedDate not supplied

Herpes simplex virus-inhibitory sulfated xylogalactans from the red seaweed Nothogenia fastigiata.

Two sulfated xylogalactans (F1 and F7), isolated from the red seaweed Nothogenia fastigiata, achieved a dose-dependent inhibition of the replication of herpes simplex virus type 1 (HSV-1) in Vero cells, with 50% effective doses in the range of 15.0-32.6 micrograms/ml, and without affecting cell viability at concentrations up to 200 micrograms/ml. The presence of sulfate groups in the molecule was essential for the antiviral properties of these polysaccharides. F7 afforded significant inhibition in HSV-1 yield if added to the cell cultures simultaneously with virus inoculum, but had no effect when it was added after 1 h of infection. Analysis of the early events of the viral replicative cycle showed that the anti-HSV effect of F7 was due to a specific inhibition of virus attachment to the host cell whereas virus internalization was not impaired.

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PubMedDate not supplied

[Antiviral activity metabolites isolated from Curvularia pallescens].

The strain BAFC 2336 of Curvularia pallescens is a hyphomycete isolated from internal fungi present in leaves and stems of Baccharis coridifolia. Three compounds designated B, D1 and D2 which inhibited the replication of vesicular stomatitis virus (VSV) and herpes simplex virus type 1 (HSV-1) in tissue cultures were isolated from fluid cultures of Curvularia pallescens. The purification procedure of the compounds consisted first in an organic solvent extraction followed by chromatography through a silica gel column. Fractions eluted from the column with antiviral activity were pooled and then subjected to thin layer chromatography (TLC) in silica gel plates. Three isolated bands were recognized with Rf of 0.63, 0.36 y 0.33 for B, D1 and D2, respectively. The chromatographic characteristics of the isolated metabolites were determined by TLC and HPLC and their chemical structure by means of spectroscopic methods. Analysis of the data obtained indicated that compound D2 (MW: 280 Da) is identical with Brefeldin A a macrolide with antiviral activity isolated from other fungi but not reported to be present in Curvularia pallescens. Compound D1 is similar in structure to compound D2; however, the low amount obtained after purification unabled us to obtain complete structural characterization. Compound B (MW: 332 Da) has an aromatic ring and a chemical structure related to curvularins, a generic name for certain metabolites from Curvularia. This compound appears to be a novel compound with antiviral potency similar to Brefeldin A, but less toxic.

Antiviral Agents↗
PubMedDate not supplied

[Prevalence of Mycoplasma orale as a contaminant of cell cultures in Argentina].

Over a period of 4 years 200 cell cultures were analysed for the presence of mycoplasma. Cultures were established cell lines from different origins, namely monkey, mouse and human, hybrid cell cultures and primary cultures. The cultures belonged to various research and industrial laboratories located in different areas of the country. Seventy per cent of investigated cultures were found to be contaminated with mycoplasma using a DNA fluorescent stain. Fifty cultures, selected at random out of the contaminated cultures, were further investigated to identify the prevalent serotype. For that purpose immunofluorescent reactions were performed using immune sera raised against several mycoplasma strains routinely found among contaminated cultures. Forty one cultures were contaminated with a single type of mycoplasma, whereas in the remaining nine, two or even three serotypes were detected. Mycoplasma orale II contaminated 40% of single infected cultures, followed by M. hyorhinis and A. laidlawii-A (12% each), M. arginini (5%), M. orale III (8%), A. laidlawii-B (2%). We were unable to serotype the remaining positive cultures, because of the lack of a full battery of immune sera against all known serotypes. The prevalence of M. orale in mycoplasma contaminated cultures thus far tested, indicates that human handling would be the main source of infection. This situation could be modified by avoiding mouth pipetting and adopting good microbiological techniques.

Acholeplasma↗
PubMedDate not supplied

[Interference associated with cell cultures chronical by infected with the Junin virus].

Supernatants from Vero cells persistently infected with Junin virus interfered with cytolitic and lethal activities of standard virus. Two Vero cell sublines, chronically infected with Junin virus named VRJ1 and VRJ3, were obtained after prolonged cultivation of cells which survived primary infection. VFJ1 was maintained over a period of 48 days, by biweekly serial transfers while VRJ3, similarly treated, was cultivated for 385 days. One of the characteristics of these cell lines was resistance against superinfection with homologous virus that ordinaily produced CPE and plaques in normal Vero cells; the cells were then considered chronically infected. Supernatants taken at different cell passage level were tested for its interference activity after centrifugation to eliminate floating cells and debris. The degree of CPE intensity caused by inoculation of Vero cells with 10(4), 10(5) or 10(6) TCID 50 of standard virus was markdely deppressed (Figure 1) by coinfection with supernatant from passage 3 of VRJ3 (VRJ1p1), VRJ1p1 supernatant also had interference activity as shown by coinfection with standard virus and expressed by plaque forming inhibition(Table 1). The plaque production of standard virus was inhibited by coinfection with VRJ1p1 supernatant which did not originate plaques when inoculated alone. The interference capacity of VRJ1p6 supernatant was reduced (Table 1) coincidentally with the formation of 55 PFU/ml. Interference activity was neutralized by Junin specific antiserum and inhibited by chloroform treatment. When Vero cells infected with VRJ1p6 supernatant were challenged with standard virus 72 hs later, an inhibition of 98% was achieved (Table 2) in contrast with value of 35% showed in Table 1.

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