Alamethicin a4665

5,5′,6,6′-tetrachloro-1,1′,3,3″-tetraethylbenzimidazolylcarbocyanine iodide (JC-1), calcein-AM, propidium iodide (PI), and rhodamine 123 were from Invitrogen (Carlsbad, CA, USA). The ATP Biomass Kit HS was from BioThema AB (Haninge, Sweden). Alamethicin A4665, ascorbic acid, bovine serum albumin (BSA), carbonyl cyanide p-(trifluoromethoxy)phenyl-hydrazone (FCCP), cyclosporin A (CsA), 7- dihydro-2-methyl-6-(4-methoxyphenyl)imidazol[1,2-a]pyrazine- 3-one (MCLA), dithionite, ethylene glycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid (EGTA), glutamate, 4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid (HEPES), mannitol, malate, polymyxin B sulfate, rotenone, sucrose, succinate, Trizma Base, tetraphenylphosphonium chloride (TPP+), N,N,N’N’-tetramethyl-p-phenylenediamide (TMPD), valinomycin, and polyethyleneglycols of different molecular weights were obtained from the Sigma-Aldrich Corporation (St Louis, MO, USA). Other chemicals were of analytical grade and were purchased from local suppliers.

Eleven toxic compounds (Sigma Aldrich, St. Louis, MO, USA) were purchased and tested:

Actinomycin D A9415 (Streptomyces spp., CAS: 50-76-0, MW 1255.42)

Alamethicin A4665 (Trichoderma arundinaceum, CAS: 27061-78-5; a mixture of Alamethicin F50 peptaibols, MW 1962, 1976, 1976 and 1990)

Calcimycin A23187 (CAS: 52665-69-7 MW 523.62)

Chaetoglobosin A (Chaetomium globosum, CAS: 50335-03-0 MW 528.64)

Citrinin (Penicillium citrinum, CAS: 518-75-2, MW 324.28)

FCCP (CAS: 370-86-5, MW 254.17)

Potassium dichromate (CAS: 7778-50-9, MW 294.18)

Ochratoxin A (Aspergillus ochraceus, CAS: 303-47-9, MW 403.81)

Sterigmatocystin (CAS: 10048-13-2 MW 324.28)

Triclosan (CAS: 3380-34-5, MW 289.54)

Valinomycin (Streptomyces spp., CAS: 2001-95-8, MW 1111.32).

The toxic solutions were prepared from the dissolved toxins, serially diluted in ethanol, and screened for toxic responses in 10-fold dilutions. Thereafter, the end-points were determined using a series of two-fold dilutions. The tested concentrations ranged from 0.01 µg·mL⁻¹ to 200 µg of ethanol-soluble substances per mL⁻¹ cell suspension.

T. viride cellulase (16,420, ‘Onozuka’ Cellulase RS) was purchased from Serva (Heidelberg, Germany). Alamethicin (A-4665 ‘from T. viride’) was from Sigma (St. Louis, MO, USA). The strain used (NRRL 3199) for alamethicin purification has been reidentified as Trichoderma arundinaceum [51 (link)], but is still named T. viride by the producer. PrI-detected permeabilisation of root tips was confirmed using T. viride alamethicin from two other suppliers (Additional file 1: Figure S1).
Statistical analysis was performed using Student’s 2-tailed unpaired t-tests in Excel (Microsoft).