Catalase cat from bovine liver

Azure A (AzA) (80%), chloroplatinic acid hexahydrate (≥99.9%), citric acid (trisodium salt), L-dehydroascorbic acid (DHA), ethanol (≥ 99.5% v/v), D(+)-glucose, H2O2 (35%), D-mannitol, L-methionine, trans-resveratrol, salicylic acid, sodium Lascorbate, sodium lauryl sulfate (SDS 95%), ascorbate oxidase (AO) from Cucurbita sp.
(156.60 units/mg solid), catalase (CAT) from bovine liver (2,200 units/mg protein) and peroxidase from horseradish (HRP, 313 units/mg solid) were obtained from Merck-Sigma-Aldrich (Spain). MeJa was purchased from Duchefa (Spain). KCl, KNO3, K2HPO4, KH2PO4 and K4Fe(CN)6 were acquired from Merck. H2SO4 and HCl were supplied by Panreac. Clopyralid 72% came from Dow AgroSciences (US).
The fungus B. cinerea was grown on potato dextrose agar plates for 20 days at 28 ºC until extensive sporulation. Spores were recovered by adding 10 ml of distilled sterile water to each plate. The suspension was filtered through nylon mesh in order to remove contaminating hyphae. A haemocytometer was used to determine the spore concentration.
For the elicitation experiments, grapevine cell cultures were cultivated with B. cinerea spores at a final concentration of 6 × 10 4 spores/mL. All the measurements were taken with freshly prepared solutions. The concentration of the H2O2 stock solutions was spectrophotometrically checked at 240 nm (ε = 43.6 M -1 cm -1 ) [28] .

Materials: Reagents and substrates including the hydrogen peroxide and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), and the enzymes catalase (CAT) from bovine liver and horseradish peroxidase (HRP) were purchased from Sigma-Aldrich (St. Louis, MO). The piezoelectric material (PZT disc) (diaphragm, 6.3 kHz, 1 KΩ, 0.01 μF, 20 mm×0.42 mm, cat. 7BB-20-6l0, Murata) was acquired from Farnell Element14 Components (Barcelona, Spain).