Euglena gracilis can grow in the mixed culture containing Cladosporium westerdijkiae, Lysinibacillus boronitolerans and Pseudobacillus badius without the addition of vitamins B1 and B12.

Euglena gracilis is a freshwater flagellate possessing secondary chloroplast of green algal origin. This protist has numerous biotechnological applications such as production of biofuels and pharmaceuticals, and it can be also used for bioremediation of polluted water and wastewater. One of the highest limitations for its large-scale cultivation is that it cannot synthesize vitamins B1 and B12 which are expensive and they have to be added to media. This study revealed that E. gracilis can be grown for long time periods without the addition of vitamins B1 and B12 in the co-culture containing filamentous fungus Cladosporium westerdijkiae, and bacteria Lysinibacillus boronitolerans and Pseudobacillus badius. Growing of E. gracilis in such co-cultures without the addition of vitamins can dramatically reduce large scale cultivation costs. Moreover, C. westerdijkiae could be used in biotechnology for immobilization and effective harvesting of E. gracilis from big cultivation containers by bioflocculation.

An ancient glaucophyte c6-like cytochrome related to higher plant cytochrome c6A is imported into muroplasts.

Cytochrome c6 is a redox carrier in the thylakoid lumen of cyanobacteria and some eukaryotic algae. Although the isofunctional plastocyanin is present in land plants and the green alga Chlamydomonas reinhardtii, these organisms also possess a cytochrome c6-like protein designated as cytochrome c6A. Two other cytochrome c6-like groups, c6B and c6C, have been identified in cyanobacteria. In this study, we have identified a novel c6-like cytochrome called PetJ2, which is encoded in the nuclear genome of Cyanophora paradoxa, a member of the glaucophytes - the basal branch of the Archaeplastida. We propose that glaucophyte PetJ2 protein is related to cyanobacterial c6B and c6C cytochromes, and that cryptic green algal and land plant cytochromes c6A evolved from an ancestral archaeplastidial PetJ2 protein. In vitro import experiments with isolated muroplasts revealed that PetJ2 is imported into plastids. Although it harbors a twin-arginine motif in its thylakoid-targeting peptide, which is generally indicative of thylakoid import via the Tat import pathway, our import experiments with isolated muroplasts and the heterologous pea thylakoid import system revealed that PetJ2 uses the Sec pathway instead of the Tat import pathway.