title: Phytotoxic action mechanism of hapalocyclamide in lettuce seedlings.
abstract: Hapalocyclamide (cyclo-thiazole-L-alanine-oxazole-D-alanine-D-thiazoline-d-phenylalanine), a hexapeptide phytotoxic compound, was isolated from the terrestrial cyanobacterium Hapalosiphon sp. The phytotoxic action of the compound was investigated in lettuce (Lactuca sativa L. cv. Great Lakes no. 366) by determining its effects on several physiological processes. Hapalocyclamide effectively inhibited mitosis process in root tips, which resulted in the suppression of primary root growth of lettuce. The compound also induced overproduction of reactive oxygen species (ROS) and loss of cell viability in root cells. Moreover, hapalocyclamide-induced lipid peroxidation in both roots and shoots. Therefore, the primary action of hapalocyclamide to suppress lettuce growth might be caused by ROS overproduction, which induces major oxidative damage to membrane lipids, resulting in cell death and growth inhibition.
authors: Graduate School of Life and Environmental Sciences, University of Tsukaba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8572, Japan.
authors: Intira
authors: I
authors: Koodkaew
authors: Yukari
authors: Y
authors: Sunohara
authors: Shigeru
authors: S
authors: Matsuyama
authors: Hiroshi
authors: H
authors: Matsumoto
mesh_terms: D016923:Cell Death / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D000458:Cyanobacteria / Q000737:chemistry*; D018545:Lactuca / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D050356:Lipid Metabolism / Q000187:drug effects; D008938:Mitosis / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects*; D010456:Peptides, Cyclic / Q000302:isolation & purification / Q000494:pharmacology*; D018517:Plant Roots / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D018520:Plant Shoots / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism*; D036226:Seedlings / Q000187:drug effects*; D013844:Thiazoles / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D010456:Peptides, Cyclic; D017382:Reactive Oxygen Species; D013844:Thiazoles; C577140:cyclo-thiazole-alanine-oxazole-alanine-thiazoline-phenylalanine