Studies on the fungitoxicity of captan

Autor: D. V. Richmond, E. Somers
Rok vydání: 1962
Předmět:
Zdroj: Annals of Applied Biology. 50:33-43
ISSN: 1744-7348
0003-4746
DOI: 10.1111/j.1744-7348.1962.tb05984.x
Popis: SUMMARY Determinations have been made by amperometric titration with silver nitrate of the total sulphydryl (SH) content of intact spores of Alternuria tenuis, Aspergillus niger, Botrytis allii, B. fabae, Coleosporium senecionis, Neurospora crassa, Penicillium expansum, P. italicum, Podosphaera leucotricha, and Rhizopus nigricans, and of yeast cells. When titrated in alcohol-ammonia buffer the cells were generally first denatured by heating with sodium dodecylsulphate; for confirmatory titrations in tris buffer on A. niger and N. crassa this pre-treatment was essential. The fungistatic activity of captan to eight of these species and the captan uptake, on an equivalent fresh weight basis, by all the fungi has also been determined: conidia of Venturia inaequalis were included in these tests. The spore dimensions, fresh and dry weights of all the fungal species are given. There was no evidence of a relationship between captan uptake and toxicity, captan uptake and spore surface area, or captan toxicity and SH content. However, captan uptake has been found to be broadly related to cell SH content; increasing SH content giving increased captan uptake. This is in agreement with our previous hypothesis that most of the captan uptake required to completely inhibit spore germination is decomposed by cell thiols before it reaches vital receptor sites. When toxic doses of captan were taken up by N. crassa spores the SH content was reduced by 35% and the molar proportions for the captan: thiol reaction were approximately 1:1.
Databáze: OpenAIRE
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