Characterization of an endopolygalacturonase produced by the apple scab fungus, Venturia inaequalis

Kollar, Andreas

doi:10.1017/s0953756297005194

Cited by 13 publications

(14 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Incubation of all cultures was static at 20°C. Media were potato dextrose broth (PDB, Difco) and the defined medium which consisted of a basal Murashige and Skoog medium with thiamine (MS) (Kollar 1998). MS-media were buffered with 0.05 M 2-(N-morpholino)ethanesulfonic acid (Mes) and adjusted to pH 4, 5 or pH 6 with NaOH/ HCl prior to sterilization.…”

Section: Media and Growth Conditionsmentioning

confidence: 99%

“…Culture filtrate proteins and mycelium associated proteins were prepared as described (Kollar 1998). Proteins of mycelia were extracted by homogenizing (Potter homogenizer) 0.1 g of lyophilized aliquots from 250 ml cultures in 10 ml water at 0°C.…”

Section: Media and Growth Conditionsmentioning

confidence: 99%

“…Tests of phenolics were performed with IEC cellulase preparations (Kollar 1994) and pectinase preparations (Kollar 1998) which were further purified by IEC. 1 ml columns (HiTrap SP, Pharmacia) were equilibrated at 1 ml/ min with 5 ml 50 mM Na-formiate, pH 4 followed by 5 ml buffer containing 1 M NaCl.…”

Section: Media and Growth Conditionsmentioning

confidence: 99%

“…Cup-plate diffusion assays were performed according to Kollar (1994Kollar ( , 1998. Substrates were 0.2% pectin (from citrus, Sigma) and 0.025% PGA (from orange, Sigma) or 0.5% carboxymethylcellulose (CMC, Sigma, high viscosity).…”

Section: Pectinase and Cellulase Assays And Inhibitor Testsmentioning

confidence: 99%

“…Once the plant cuticle is penetrated pectinases followed by cellulases may be the first important classes of enzymes produced (Kollar 1994(Kollar , 1998. A balanced degradation is expected because there is no disruption of host tissue and a lack of direct cell killing.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Effects of apple (Malus × domestica Borkh.) phenolic compounds on proteins and cell wall-degrading enzymes of Venturia inaequalis

Golba

Treutter

Kollar

2011

Trees

View full text Add to dashboard Cite

Cell wall-degrading enzymes of Venturia inaequalis are supposed to be fungal virulence factors whereas phenolic compounds of the host plant may be involved in defence. Since phenolic structures are predestined for an interaction with proteins we studied the effects on enzymes and proteins in course of in vitro culture and with preparations from culture filtrates and mycelia, respectively. The native compounds epicatechin, catechin, phloridzin, chlorogenic acid, caffeic acid, p-coumaric acid and phloridzin tested under non-oxidizing conditions had no or weak effects on enzyme activities. A significant inhibition of pectinase was only detected with the highest concentrations of procyanidins and phloretin. Aerobe conditions resulted in a fast oxidation of most phenolics which was enhanced by fungal phenoloxidases. Generally, no inhibition of fungal growth occurred in vitro but distinct irreversible effects on proteins and enzymes were detected with oxidized phenolics in course of in vitro-cultures as well as with the corresponding preparations. Efficacy of inhibitory activity in in vitro-cultures depended on media, culture technique and time course. Direct treatment of enzyme preparations with the oxidized phenolics resulted in a distinct inhibition of cellulolytic and especially pectinolytic activity. Apart from cellulase pattern altered by phenolics, in vitro-culture zymograms revealed a non specific reduction of enzymatic activities, whereas action on total culture filtrate proteins resulted in specific effects due to phenolic compounds and incubation time. An attempt was made to characterize the oxidation products of epicatechin. Chromatographic fractionation revealed a nonresolvable complex of inhibitory compounds which were not consistent with the typical yellow oxidation products.

show abstract

Section: Media and Growth Conditionsmentioning

confidence: 99%

Section: Media and Growth Conditionsmentioning

confidence: 99%