Action of Antiviral Agents

Hirai, Takeshi

doi:10.1016/b978-0-12-356401-6.50022-x

Cited by 6 publications

(4 citation statements)

References 102 publications

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“…Surprisingly, after 1 h, the rate ofdecreasing protection slowed down so that the glucan preparation still afforded about 80% protection when applied 8 to 10 h after virus inoculation. However, the glucan preparation, at 10 ,g/mL, lost all apparent ability to protect the plant when applied 12 to 24 h after virus inoculation. Similar results were obtained when the glucan preparation was injected instead of inoculated.…”

Section: Relationship Between the Order Of Application Of Virus And Tmentioning

confidence: 99%

“…Some inhibitors of viral infection have been found in extracts of plants and appear to be proteinaceous in nature (3,10). Other inhibitors of viral infection have been obtained from bacteria, yeast, and fungi (for reviews, see refs.…”

Section: Mechanism By Which the Glucan Preparation Protectsmentioning

confidence: 99%

“…Other inhibitors of viral infection have been obtained from bacteria, yeast, and fungi (for reviews, see refs. 3,10). It was suggested as long ago as the 1930s that some inhibitors of viral infection might be polysaccharides, because the inhibitors tolerated boiling and high concentrations of ethanol.…”

Section: Mechanism By Which the Glucan Preparation Protectsmentioning

confidence: 99%

“…DISCUSSION Inhibitors of plant viruses may be divided into two categories (3,10): those that inhibit virus infection and those that inhibit virus multiplication. The former are substances that inactivate virus infectivity in vitro or that, when applied to leaves simultaneously with virus inoculation, prevent infection from occurring.…”

Section: Mechanism By Which the Glucan Preparation Protectsmentioning

confidence: 99%

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Host-Pathogen Interactions

Kopp¹,

Rouster²,

Fritig³

et al. 1989

Plant Physiol.

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A glucan preparation obtained from the mycelial walls of the fungus Phytophthora megasperma f.sp. glycinea and known as an elicitor of phytoalexins in soybean was shown to be a very efficient inducer of resistance against viruses in tobacco. The glucan preparation protected against mechanically transmitted viral infections on the upper and lower leaf surfaces. Whether the glucan preparation was applied by injection, inoculation, or spraying, it protected the plants if applied before, at the same time as, or not later than 8 hours after virus inoculation. At concentrations ranging from 0.1 to 10 micrograms per milliliter, the glucan preparation induced protection ranging from 50 to 100% against both symptom production (necrotic local lesions, necrotic rings, or systemic mosaic) and virus accumulation in all Nicotiana-virus combinations examined. However, no significant protection against some of the same viruses was observed in bean or turnip. The host plants successfully protected included N. tabacum (9 different cultivars), N. sylvestris, N. glutlnosa, and N. clevelandii.The viruses belonged to several taxonomic groups including tobacco mosaic virus, alfalfa mosaic virus, and tomato black ring virus. The glucan preparation did not act directly on the virus and did not interfere with virus disassembly; rather, it appeared to induce changes in the host plant that prevented infections from being initiated or recently established infections from enlarging. The induced resistance does not depend on induction of pathogenesis-related proteins, the phenylpropanoid pathway, ligninlike substances, or callose-like materials. We believe the induced resistance results from a mechanism that has yet to be described. the observed resistance (for recent reviews, see 8, 26). The metabolic alterations that occur during a viral-induced hypersensitive reaction appear to be similar to those that occur in the same host during incompatible interactions with pathogenic bacteria and fungi (7). The most commonly observed metabolic changes are the production of phytoalexins and phenylpropanoid metabolites. In previous reports, it was shown that the phenylpropanoid pathway is strongly activated ( 15) in tobacco leaves reacting hypersensitively to TMV2 and that the virus localizing mechanism was weakened (larger lesions) if infected leaves were treated with competitive inhibitors of phenylalanine ammonia-lyase, a key enzyme in the pathway (19,20). This suggested an involvement of the activated phenylpropanoid pathway in the localizing mechanism.Treatment of various plant materials with elicitors of microbial origin have been shown to mimic defense responses and to stimulate the pathways leading to phenylpropanoids and flavonoids (for reviews, see 1, 4). Among these elicitors were cell wall fragments and substances present in the culture filtrates ofthe fungus Phytophthora megasperma f.sp. glycinea (Pmg) (1, 2). In particular, poly-and oligosaccharides extracted and purified from cell walls of this fungus were shown to exhibit very h...

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Section: Relationship Between the Order Of Application Of Virus And Tmentioning

confidence: 99%

Section: Mechanism By Which the Glucan Preparation Protectsmentioning

confidence: 99%

Section: Mechanism By Which the Glucan Preparation Protectsmentioning

confidence: 99%

Section: Mechanism By Which the Glucan Preparation Protectsmentioning

confidence: 99%

See 2 more Smart Citations

Host-Pathogen Interactions

Kopp¹,

Rouster²,

Fritig³

et al. 1989

Plant Physiol.

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Geförderte Plaquebildung in RNA‐Phagen/Bakterien‐Systemen unter dem Einfluß oberflächenaktiver Präparate

Menzel

1985

J. Basic Microbiol.

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The effect of 21 surfactants on the plaque formation was tested in three RNA-phages/Escherichia coli systems and in one RNA-phage/Pseudomonas aeruginosa system. Especially anionic detergents proved to be able to influence the plaque formation substantially. In high concentrations of Metaupon, Fekunil 602, Fekunil S-BA, Emulgator W 270, and Emulgator O-BA the plaque formation by the phages M 12 and f2 was inhibited and in low concentrations it was promoted. In the system Q beta/E. coli AB 301 the effect of the detergents mentioned was restricted to the prevention of the appearance of plaques. The detergent E 30 brought about only plaque inhibitions, too, in all used RNA-phages/E. coli systems. The treatment with effective detergents in the system PP7/P. aeruginosa, however, increased only the number of plaques. This phenomenon was evident in the formation of radiate plaque patterns in the lawn of bacteria. In the case of RNA-phages of E. coli the formation of such trains of lysis depends on the choice of the nutritive medium. The addition of the detergent Fekunil 602 at different times after the contact between phages and host bacteria affects the length of the beams of lysis. The ionogenity of surfactants seems to be of importance for the formation of radiate plaque patterns, since the tested cationic compound and the nonionic surfactants, contrary to anionic surfactants, did not cause any beams of lysis.

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Is there a plant interferon?

Chessin

1983

Bot. Rev

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Action of Antiviral Agents

Cited by 6 publications

References 102 publications

Host-Pathogen Interactions

Host-Pathogen Interactions

Geförderte Plaquebildung in RNA‐Phagen/Bakterien‐Systemen unter dem Einfluß oberflächenaktiver Präparate

Is there a plant interferon?

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