title: Blue and red light-induced germination of resting spores in the red-tide diatom Leptocylindrus danicus.
abstract: Photophysiological and pharmacological approaches were used to examine light-induced germination of resting spores in the red-tide diatom Leptocylindrus danicus. The equal-quantum action spectrum for photogermination had peaks at about 440 nm (blue light) and 680 nm (red light), which matched the absorption spectrum of the resting spore chloroplast, as well as photosynthetic action spectra reported for other diatoms. DCMU, an inhibitor of photosynthetic electron flow near photosystem II, completely blocked photogermination. These results suggest that the photosynthetic system is involved in the photoreception process of light-induced germination. Results of pharmacological studies of the downstream signal transduction pathway suggested that Ca(2+) influx is the closest downstream neighbor, followed by steps involving calmodulin, nitric oxide synthase, guanylyl cyclase, protein-tyrosine-phosphatase, protein kinase C and actin polymerization and translation.
authors.affiliation: School of Advanced Sciences, Graduate University for Advanced Studies (Sokendai), Hayama, Kanagawa, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Shikata
authors.forename: Mineo
authors.initials: M
authors.lastname: Iseki
authors.forename: Shigeru
authors.initials: S
authors.lastname: Matsunaga
authors.forename: Sho-ichi
authors.initials: S
authors.lastname: Higashi
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kamei
authors.forename: Masakatsu
authors.initials: M
authors.lastname: Watanabe
mesh_terms: D000199:Actins / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002147:Calmodulin / Q000378:metabolism; D002736:Chloroplasts / Q000378:metabolism* / Q000528:radiation effects; D046508:Culture Techniques; D017377:Diatoms / Q000378:metabolism*; D004237:Diuron / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors / Q000378:metabolism; D057097:Harmful Algal Bloom; D008027:Light; D055537:Light Signal Transduction / Q000528:radiation effects*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D055668:Photochemical Processes / Q000528:radiation effects; D010788:Photosynthesis / Q000528:radiation effects; D045332:Photosystem II Protein Complex / Q000037:antagonists & inhibitors / Q000378:metabolism; D058105:Polymerization; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism; D013057:Spectrum Analysis; D013170:Spores / Q000378:metabolism* / Q000528:radiation effects
chemical_list: D000199:Actins; D002147:Calmodulin; D004791:Enzyme Inhibitors; D045332:Photosystem II Protein Complex; D004237:Diuron; D019001:Nitric Oxide Synthase; D011493:Protein Kinase C; D017027:Protein Tyrosine Phosphatases; D006162:Guanylate Cyclase; D002118:Calcium