title: PARTICIPATION OF EXTRACELLULAR NUCLEOTIDES IN THE WOUND RESPONSE OF DASYCLADUS VERMICULARIS AND ACETABULARIA ACETABULUM (DASYCLADALES, CHLOROPHYTA)(1).
abstract: As assayed by fluorescent reporter dyes, nitric oxide (NO) and H2 O2 , two downstream signaling agents induced by wounding in the alga Dasycladus vermicularis (Scop.) Krasser, can also be induced in unwounded Dasycladus cells by μM Adenosine 5'[γ-thio]triphosphate (ATPγS) and Adenosine 5'-[β-thio]diphosphate (ADPβS), but not by Adenosine 5'-O-thiomonophosphate (AMPS). These nucleotide-induced responses are blocked by pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS), an antagonist of animal purinoceptors, and by adenosine, a feed-back inhibitor of extracellular nucleotide responses in animals. Similar nucleotide- and nucleotide-antagonist responses were observed in Acetabularia acetabulum (L.) P. C. Silva. Significant levels of ATP released from Dasycladus cells were measured at wound sites by a sensitive luciferin-luciferase assay. Additionally, the normal wound-induced production of NO and H2 O2 in Dasycladus can be blocked by pretreating the cells with PPADS. Our results indicate that nucleotides released from wounds can serve as a signal to trigger wound responses in algae, and that coordinated signaling between extracellular nucleotides and the NO pathway may have been established early during the evolution of plants.
authors.affiliation: Section of Molecular Cell and Developmental Biology, University of Texas, Austin, Texas 78712, USA.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Torres
authors.affiliation: Section of Molecular Cell and Developmental Biology, University of Texas, Austin, Texas 78712, USA.
authors.forename: Amy
authors.initials: A
authors.lastname: Rivera
authors.affiliation: Section of Molecular Cell and Developmental Biology, University of Texas, Austin, Texas 78712, USA.
authors.forename: Greg
authors.initials: G
authors.lastname: Clark
authors.affiliation: Section of Molecular Cell and Developmental Biology, University of Texas, Austin, Texas 78712, USA.
authors.forename: Stanley J
authors.initials: SJ
authors.lastname: Roux
keywords: Acetabularia acetabulum; Dasycladus vermicularis; extracellular ATP; hydrogen peroxide; macroalgae; nitric oxide; purinoceptor antagonist; wounding