1887

Abstract

Summary: Resistance to the low fungal epipolythiodiketopiperazine toxin, gliotoxin, varied threefold between the phytopathogens and Uptake of radiolabelled gliotoxin was rapid and concentration dependent. Uptake by was largely complete within 1 min while the rate of uptake peaked within 10 min for (anastomosis groups 2-2 and 4). Uptake of gliotoxin by was twice that shown by the more resistant A deep rough mutant of , deficient in outer-membrane polysaccharide synthesis, was hypersensitive to gliotoxin, indicating that diffusion barriers play a role in relative sensitivity to gliotoxin. Fungal glutathione levels (reduced and oxidized) did not differ appreciably before or after gliotoxin exposure, indicating that this cytoplasm-based detoxification mechanism was not important in the relative fungal sensitivity to gliotoxin. Binding of the radiolabelled thiol reagents -ethylmaleimide (NEM) and iodoacetic acid to fungal thiol groups was inhibited by gliotoxin. Conversely, the thiol reagents NEM and -chloromercuribenzoic acid inhibited the uptake of radiolabelled gliotoxin. Uptake of radiolabelled amino acids and glucose was reduced by up to 85% by gliotoxin (8 μg ml). It is suggested that the primary mechanism of action of gliotoxin involves selective binding to cytoplasmic membrane thiol groups.

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/content/journal/micro/10.1099/00221287-134-7-2067
1988-07-01
2019-11-18
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http://instance.metastore.ingenta.com/content/journal/micro/10.1099/00221287-134-7-2067
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