botrydium granulatum

[iranplant]

Botrydium (bot-rid-ee-um) xanthophyte - a group of walled stramenopiles although unlike most stramenopiles with plastids, the xanthophytes have a much greener colour. Botrydium is usually assigned to the Vaucheriales, which are characterised by being able to adopt a coenocytic (multinucleate) body form. Normally grows on mud, often with aerial and subsurface elements. This image shows a number of the forms adopted by the vegetative cells. Phase contrast. This picture was taken by David Patterson and Craig Bailey of material maintained in culture by Craig Bailey in April, 2001. Image copyright: D. J. Patterson and Craig Bailey, image used under license to MBL (micro*scope).

DISTRIBUTION OF THE MITOCHONDRIAL DEVIANT GENETIC CODE AUA FOR METHIONINE IN HETEROKONT ALGAE

Megumi Ehara, Kazuo I. Watanabe, Hiroshi Kawai, Yuji Inagaki, Yasuko Hayashi-Ishimaru, Takeshi Ohama,
Department of Biology, Faculty of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan Research Center for Inland Seas, Kobe University, Rokkodai, Kobe 657–8501, Japan JT Biohistory Research Hall, 1-1 Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
Copyright © 1998 The Phycological Society of America, Inc.

KEYWORDS
cytochrome oxidase subunit I • deviant genetic code • heterokont algae • Phaeophyceae • Xanthophyceae
ABSTRACT


The DNA sequence of the cytochrome oxidase subunit I (COXI) gene (1059 bp), was determined in a number of heterokont algae, including five species of the Phaeophyceae [Chorda filum (Linnaeus) Stackhouse, Colpomenia bullosa (Saunders) Yamada, Ectocarpus sp., Pseudochorda nagaii (Tokida) Inagaki, Undaria pinnatifida (Harvey) Suringar], and a member of the Raphidophyceae [Chattonella antiqua (Hada) Ono]. The distribution of a deviant mitochondrial code, the AUA codon for methionine (AUA/Met), which was previously reported in the Xanthophyceae, was inferred from these COXI sequences. Comparative analyses of these sequences revealed that all the algae described above bear the universal genetic code, including the assignment for the AUA codon. A phylogenetic tree was constructed using the obtained sequences along with already-published COXI sequences of various heterokont algae. The clusters of the Xanthophyceae and the Phaeophyceae were resolved as sister groups with high bootstrap support, excluding a bacillariophycean species, a raphidophycean species, and three species of the Eustigmatophyceae. Taking the distribution of the deviant code and the COXI phylogenetic tree together, the genetic code change most probably occurred in an ancestor of the Xanthophyceae after it had branched off from the Phaeophyceae.