title: Variation in storage alpha-glucans of the Porphyridiales (Rhodophyta).
abstract: Storage glucans were analyzed in the Porphyridiales which include the most primitive and phylogenetically diverged species in the Rhodophyta, to understand early evolution of the glucan structure in the Rhodophyta. The storage glucans of both Galdieria sulphuraria and Cyanidium caldarium consisted of glycogen, while those of Rhodosorus marinus, Porphyridium purpureum, P. sordidum and Rhodella violacea could be defined as semi-amylopectin. X-ray diffraction analysis of the glucans demonstrated variation in the crystalline structure: the patterns in P. purpureum and R. violacea were of A- and B-types, respectively, while alpha-glucans of R. marinus and P. sordidum displayed structures with lower crystallinity. Electron microscopic observations indicated that the alpha-glucans of P. sordidum consisted of two kinds of granules; a minor component of more dense granules with crystalline leaflets and a major component of softer ones without crystalline structure. Gel permeation chromatography showed that all the species containing the semi-amylopectin-type glucans also contained amylose, although the relative amounts of this fraction were different depending on the species. Our results are consistent with two distinct evolution scenarios defined either by the independent acquisition of semi-crystalline starch-like structures in the different plant lineages or more probably by the loss of starch and reversion to glycogen synthesis in cyanidian algae growing in hot and acid environments.
authors: School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, 192-0392 Japan.
authors: Takahiro
authors: T
authors: Shimonaga
authors: Mai
authors: M
authors: Konishi
authors: Yasunori
authors: Y
authors: Oyama
authors: Shoko
authors: S
authors: Fujiwara
authors: Aya
authors: A
authors: Satoh
authors: Naoko
authors: N
authors: Fujita
authors: Christophe
authors: C
authors: Colleoni
authors: Alain
authors: A
authors: Buléon
authors: Jean-Luc
authors: JL
authors: Putaux
authors: Steven G
authors: SG
authors: Ball
authors: Akiko
authors: A
authors: Yokoyama
authors: Yoshiaki
authors: Y
authors: Hara
authors: Yasunori
authors: Y
authors: Nakamura
authors: Mikio
authors: M
authors: Tsuzuki
mesh_terms: D002236:Carbohydrate Conformation; D005936:Glucans / Q000737:chemistry* / Q000378:metabolism* / Q000648:ultrastructure; D000461:Rhodophyta / Q000378:metabolism*
chemical_list: D005936:Glucans