A photoreceptor with characteristics of phytochrome triggers sporulation in the true slime mould Physarum polycephalum

Abstract

Phytochrome is a ubiquitous photoreceptor in plants that controls a variety of responses to light, including gene expression, differential cell growth and intracelhilar movement of organelles. All phytochromes analysed so far are reversibly interconverted by light between an inactive and an active conformation, each of which has a different and characteristic absorbance spectrum. Based on photophysiological measurements we provide evidence, that a photoreceptor with these unique properties of phytochrome triggers sporulation in the true slime mould Physarum polycephalum.

Studies on the Structure and Function of Phytochromes as Photoreceptors Based on Synthetic Organic Chemistry

“…4,8 Phytochromes, one of the best-characterized photoreceptors in plants, are a widespread family of red/far-red light responsive photoreceptors first discovered in plants 9,10 and have been recently also discovered in bacteria, [11][12][13] fungi, 14 and slime molds. 15 They play critical roles in various light-regulated processes, ranging from phototaxis and pigmentation in bacteria to seed germination, chloroplast development, shade avoidance, and flowering in higher plants. All phytochromes have a covalently attached linear tetrapyrrole (bilin) chromophore that absorbs light in red and far-red region.…”

Total Syntheses of Sterically Locked Phycocyanobilin Derivatives Bearing a 15Z-anti or a 15E-anti CD-Ring Component

“…The Henry reaction with 1-nitropropane followed by acetylation in the presence of 4-(dimethylamino)-pyridine (DMAP) gave a mixture of nitro diacetate compound 17 and the corresponding nitro olefin 18, which was allowed to react with t-butyl isocyanoacetate without separation in the presence of DBU applying Barton's method 21 to give the pyrrole derivative 19 in 26% yield from 13 in four steps. Iodination of the ¡-position of the pyrrole 19 with Niodosuccinimide (NIS) followed by oxidation utilizing Pb(OAc) 4 in toluene 22 gave the pyrrolinone derivative 21 in 90% yield from 19. The ¡-acetoxy group of the pyrrolinone derivative 21 was replaced with a Ts group using anhydrous TsNa in 94% yield, followed by protection of the pyrrolinone-NH using Boc 2 O to give 23 in 86% yield.…”

“…The organic solvent was removed under reduced pressure, and the residue was partitioned between AcOEt and water. The organic extract was washed successively with saturated aqueous solutions of NaHSO 3 , NaHCO 3 , brine, and dried over MgSO 4 . After evaporation of the solvent, the residue was dissolved in xylene (10 mL) and the solution was refluxed with stirring for 1 h. After removal of the solvent under reduced pressure, the obtained solid product was recrystallized from AcOEt/hexane to give 10.…”

“…The organic extract was successively washed with saturated aqueous solutions of NaHSO 3 , NaHCO 3 6 mmol] in toluene (30 mL) was stirred at room temperature for 2 d. 22 The reaction mixture was filtered through a pad of Celite and the filtrate was partitioned between AcOEt and water. The organic extract was successively washed with saturated aqueous solutions of NaHSO 3 , NaHCO 3 , brine, and then dried over MgSO 4 …”

“…4 They play critical roles in various light-regulated processes, ranging from phototaxis and pigmentation in bacteria to seed germination, chloroplast development, shade avoidance, and flowering in higher plants. All phytochromes have a covalently attached linear tetrapyrrole (bilin) chromophore that absorbs light in the red and far-red region.…”