title: Programmed cell death in plants: protective effect of phenolic compounds against chitosan and H2O2.
abstract: Addition of chitosan or H2O2 caused destruction of nuclei of epidermal cells (EC) in the epidermis isolated from pea leaves. Phenol, a substrate of the apoplastic peroxidase-oxidase, in concentrations of 10(-10)-10(-6) M prevented the destructive effect of chitosan. Phenolic compounds 2,4-dichlorophenol, catechol, and salicylic acid, phenolic uncouplers of oxidative phosphorylation pentachlorophenol and 2,4-dinitrophenol, and a non-phenolic uncoupler carbonyl cyanide m-chlorophenylhydrazone, but not tyrosine or guaiacol, displayed similar protective effects. A further increase in concentrations of the phenolic compounds abolished their protective effects against chitosan. Malate, a substrate of the apoplastic malate dehydrogenase, replenished the pool of apoplastic NADH that is a substrate of peroxidase-oxidase, prevented the chitosan-induced destruction of the EC nuclei, and removed the deleterious effect of the increased concentration of phenol (0.1 mM). Methylene Blue, benzoquinone, and N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) capable of supporting the optimal catalytic action of peroxidase-oxidase cancelled the destructive effect of chitosan on the EC nuclei. The NADH-oxidizing combination of TMPD with ferricyanide promoted the chitosan-induced destruction of the nuclei. The data suggest that the apoplastic peroxidase-oxidase is involved in the antioxidant protection of EC against chitosan and H2O2.
authors.affiliation: Department of Physiology of Microorganisms, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia. vdsamuilov@mail.ru
authors.forename: V D
authors.initials: VD
authors.lastname: Samuilov
authors.forename: L A
authors.initials: LA
authors.lastname: Vasil'ev
authors.forename: E V
authors.initials: EV
authors.lastname: Dzyubinskaya
authors.forename: D B
authors.initials: DB
authors.lastname: Kiselevsky
authors.forename: A V
authors.initials: AV
authors.lastname: Nesov
mesh_terms: D016923:Cell Death / Q000187:drug effects; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D048271:Chitosan / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005292:Ferricyanides / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D008293:Malates / Q000494:pharmacology; D010088:Oxidoreductases / Q000378:metabolism; D018532:Pisum sativum / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D019800:Phenol / Q000378:metabolism / Q000494:pharmacology*; D010847:Picolines / Q000494:pharmacology; D019441:Plant Epidermis / Q000166:cytology / Q000187:drug effects
chemical_list: C524030:1-(3-picolinium)-12-triethylammonium-dodecane dibromide; D005292:Ferricyanides; D008293:Malates; D010847:Picolines; D019800:Phenol; C030298:malic acid; D048271:Chitosan; D006861:Hydrogen Peroxide; D010088:Oxidoreductases; C028033:potassium ferricyanide