Diversity and Evolutionary History of the Symbiontida (Euglenozoa)

摘要: Several lineages of euglenozoans are enveloped with epibiotic bacteria and live in low oxygen anoxic marine sediments, such as Bihospites bacati Calkinsia aureus. A combination shared ultrastructural traits molecular phylogenetic inferences demonstrate that these belong to a clade called the “Symbiontida”. possess all synapomorphies for Euglenozoa plus several novel traits. has distinctive cell surface organization reminiscent pellicle strips euglenids, robust C-shaped feeding apparatus encircles nucleus, diverse community bacteria. “extrusomal pocket” thick (orange) extracellular matrix beneath uniform layer Despite absence data, similar Postgaardi mariagerensis its strongly suggest this species is also member Symbiontida. Molecular trees inferred from small subunit (SSU) ribosomal DNA sequences have shown group set environmental (eDNA) generated low-oxygen samples collected at different depths locations around world. These data array symbiontids yet be characterized genomic, cellular, behavior levels, which underscores how poorly we currently understand biology ecology group. Moreover, current communities associated Bihospites, co-evolved their hosts metabolically integrated modified mitochondria positioned immediately host’s plasma membrane. No symbiontid ever been cultivated, so improved knowledge about eukaryotic organisms intimate relationships environments will likely achieved using culture-independent approaches, isolated-cell metagenomics.