Galdieria sulphuraria

Image of Galdiera sulphuraria courtesy of National Geographic.

Classification

Domain: Eukaryota; Class: Rhodophyta; Family: Cyanidiaceae; Genus: Galdieria

Phylogeny of ATPases in G. sulphuria Gerald Schönknecht et al. [Science 339, 1207 (2013).]

Species

Species: Galdiera sulphuraria

Description and Significance

Galdieria sulphuraria is a eukaryotic, spore-forming, coccus. G. sulphuraria appears yellow-green to dark blue-green grown heterotrophically in liquid culture, and often yellow or green in its natural environment. It is an acidophile, as well a thermophile, and inhabits highly acidic springs at high temperatures.

G. sulphuraria is a mixotrophic organism capable of both photosynthesis and the catabolism of a wide variety of metabolites.

Genome Structure

Phylogenetic and genomic analyses supplied by, Gerald Schönknecht et al. revealed 75 indications of horizontal gene transfer from archaea and bacteria along with highly condensed protein coding regions within the G. sulphuraria genome[6]. It is speculated that minimally 5% of the functional genes were acquired in this way [1].

Success of G. sulphuraria in a diverse array of extreme habitats appears to be facilitated by the acquisition and subsequent duplication of variety of genes not limited to heat tolerant archael ATPases, halophilic sodium-proton antiporters, arsenical membrane protein pump genes of thermoacidophiles and proteobacterial mercuric reductase enzymes [6].

Cell Structure, Metabolism and Life Cycle

"presents a vacuole, a multilobed chloroplast and a net-like mitochondrion" [2]

"This alga shows an enormous metabolic flexibility, growing either photoautotrophically or heterotrophically on more than 50 carbon sources" [3]

Ecology

Image of Galdieria sulphuraria in Reykjavik http://www.nationalgeographic.com National Geographic.

"The unicellular red micro-alga Galdieria sulphuraria (Cyanidiales) is a eukaryote that can represent up to 90% of the biomass in extreme habitats such as hot sulfur springs with pH values of 0 to 4 and temperatures of up to 56°C." [4]

"Some microbial eukaryotes, such as the extremophilic red alga Galdieria sulphuraria, live in hot, toxic metal-rich, acidic environments" [5]