Plastid Genome Evolution of Two Colony-Forming Benthic Strains (Coccolithales, Haptophyta).

Coccolithophores are well-known haptophytes that produce small calcium carbonate coccoliths, which in turn contribute to carbon sequestration in the marine environment. Despite their important ecological role, only two of eleven haptophyte plastid genomes are from coccolithophores, and those two belong to the order Isochrysidales. Here, we report the plastid genomes of two strains of (Coccolithales) from Spain (CCAC 3688 B) and the USA (A15,280).

Development of a species-specific transformation system using the novel endogenous promoter calreticulin from oleaginous microalgae Ettlia sp.

Microalgae not only serve as raw materials for biofuel but also have uses in the food, pharmaceutical, and cosmetic industries. However, regulated gene expression in microalgae has only been achieved in a few strains due to the lack of genome information and unstable transformation. This study developed a species-specific transformation system for an oleaginous microalga, Ettlia sp.

Amoeba Genome Reveals Dominant Host Contribution to Plastid Endosymbiosis.

Eukaryotic photosynthetic organelles, plastids, are the powerhouses of many aquatic and terrestrial ecosystems. The canonical plastid in algae and plants originated >1 Ga and therefore offers limited insights into the initial stages of organelle evolution. To address this issue, we focus here on the photosynthetic amoeba Paulinella micropora strain KR01 (hereafter, KR01) that underwent a more recent (∼124 Ma) primary endosymbiosis, resulting in a photosynthetic organelle termed the chromatophore.

Differential proteomic analyses of green microalga Ettlia sp. at various dehydration levels.

Water deprivation could be a lethal stress for aquatic and aero-terrestrial organisms. Ettlia sp. is a unicellular photosynthetic freshwater microalga.

Evolutionary dynamics of the chromatophore genome in three photosynthetic Paulinella species.

The thecate amoeba Paulinella is a valuable model for understanding plastid organellogenesis because this lineage has independently gained plastids (termed chromatophores) of alpha-cyanobacterial provenance. Plastid primary endosymbiosis in Paulinella occurred relatively recently (90-140 million years ago, Mya), whereas the origin of the canonical Archaeplastida plastid occurred >1,500 Mya. Therefore, these two events provide independent perspectives on plastid formation on vastly different timescales.

Light intensity as major factor to maximize biomass and lipid productivity of Ettlia sp. in CO-controlled photoautotrophic chemostat.

The optimal culture conditions are critical factors for high microalgal biomass and lipid productivity. To optimize the photoautotrophic culture conditions, combination of the pH (regulated by CO supply), dilution rate, and light intensity was systematically investigated for Ettlia sp. YC001 cultivation in a chemostat during 143days.