The Electrokinetic Properties of Some Fungal Spores

Abstract

SUMMARYThe electrophoretic mobilities of conidia of Alternaria tenuis, Botrytis fabae, Penicillium expansum, Erysiphe graminis, Podosphaera leucotricha and Venturia inaequalis, basidiospores of Stereum purpureum, sporangia and encysted zoospores of Phytophthora infestans were determined in solution at various pH values. The spores all had characteristic and distinct pHmobility curves. The zero mobility of P. infestans sporangia over the range pH 2 to 11 is consistent with a cellulose surface free from ionizable groups. The mobility of basidiospores of S. purpureum depended entirely on the presence of carboxyl groups. Chemical and enzymic treatments showed both amino and carboxyl groups on A . tenuis and B. fabae; phosphate was present in addition onP. expansum. The amino groups of e-lysine, histidine and leucine contributed to the surface charge of B. fabae; amino acids and tyrosine were detected on A. tenuis. The surface of P. expansum was proteinfree and the amino groups present were probably derived from a glucosamine or galactosamine polymer. Washed cell walls and intact conidia of B. fabae were electrophoretically similar but cell walls of P. expansum, unlike normal conidia, were phosphate-free. Mycelial 'protoplasts ' of A. tenuis and Neurospora crassa and conidial 'protoplasts ' of B. fabae had pH-mobility curves characteristic of a protein surface. investigated in detail the elecktrokinetic properties of conidia, protoplasts and cell walls of Neurospora crassa. The latter workers found amino, carboxyl and phosphate groups to be present on the spore surface, but phosphate groups were absent from washed spore walls. The cationic surface-active fungicide dodine (n-dodecylguanidine acetate) decreased the negative charge on conidia to zero and with increasing concentration gave a positive charge to the spores. The negative charge on cell walls and 'protoplasts ' was neutralized at lower fungicide concentrations.The present work is part of an investigation into the reaction between fungicides and the components of the fungal spore surface. The electrokinetic properties of spores from the following species have been studied to determine the nature of the ionizable surface groups : conidia of Alternaria tenuis Nees, Botrytis fabae Sardiiia, Penicillium expansum Link em. Thom, Erysiphe graminis DC. ex MCrat, Podosphaera leucotricha (Ellis & Everh.) Salm., Venturia inaequalis (Cooke) Wint. ; basidiospores of Stereum 4-2

The Electrophoretic Properties and Some Surface Components of Penicillium Conidia

“…I) are indicative of amino-carboxyl surfaces containing varying amounts of phosphate. The curve of P. notatum is remarkably similar to that of P. expansum after complete phosphate removal (Fisher & Richmond, 1969).…”

“…Removal of phosphate by enzyme action or prolonged washing revealed an underlying amino-carboxyl surface D. J. FISHER AND D. V. RICHMOND (Fisher & Richmond, 1969). The curves of the other Penicillium species (Fig.…”

“…The alkaline extract was dialysed against running water overnight (Gould, Stubbs & King, 1970). Amino acids in the extracted non-dialysable wall material were determined on a Technicon TSM.1 amino acid analyser after hydrolysis with 6 M-HCl at 100" in an atmosphere of N2 for 2 1 h. (Fisher & Richmond, 1969). Measurements were made on conidia which had been washed once with the appropriate buffer before suspension in HCI+NaCl or barbiturate+acetate buffer ( I : 0.05) of the required pH (Gittens & James, 1963).…”

Effects of Junlon and Hostacerin on the Electrokinetic Properties of Spores of Aspergillus niger, Phanerochaete chrysosporium and Geotrichum candidum

“…niger conidia, as suggesting that the predominant ionizable groups on the spore surface were possibly phosphate or carboxyl. Spores of Penicilliurn expansum also had an isoelectric point at pH 2.0 and Fisher & Richmond (1969) suggested that their surface contained highly acidic phosphate groups.…”

“…niger was similar to that of A . niger spores that had been incubated at pH 4.5 for 12 h (Seviour & Read, 1985), and freshly harvested spores of P. chrysosporium had a pH-mobility curve which was similar to that of conidia of Penicilliurn expansum (Fisher & Richmond, 1969). However, freshly harvested spores of G. candidurn had a peak of negative spore mobility (i.e.…”