"''Candidatus'' Azoamicus ciliaticola" is a

candidate A candidate, or nominee, is the prospective recipient of an award or honor, or a person seeking or being considered for some kind of position; for example: * to be elected to an office — in this case a candidate selection procedure occurs. * t ...

species of

endosymbiotic An ''endosymbiont'' or ''endobiont'' is any organism that lives within the body or cells of another organism most often, though not always, in a mutualistic relationship. (The term endosymbiosis is from the Greek: ἔνδον ''endon'' "within ...

bacteria belonging to the eub62A3 group of

Gammaproteobacteria Gammaproteobacteria is a class of bacteria in the phylum Pseudomonadota (synonym Proteobacteria). It contains about 250 genera, which makes it the most genera-rich taxon of the Prokaryotes. Several medically, ecologically, and scientifically imp ...

, characterized for its capacity to perform

denitrification Denitrification is a microbially facilitated process where nitrate (NO3−) is reduced and ultimately produces molecular nitrogen (N2) through a series of intermediate gaseous nitrogen oxide products. Facultative anaerobic bacteria perform denitr ...

within its

ciliate The ciliates are a group of alveolates characterized by the presence of hair-like organelles called cilia, which are identical in structure to flagellum, eukaryotic flagella, but are in general shorter and present in much larger numbers, with a ...

host in anaerobic water environments. It was isolated from

Lake Zug __NOTOC__ Lake Zug (german: Zugersee) is a lake in Central Switzerland, situated between Lake Lucerne and Lake Zurich. It stretches for 14 km between Arth and the Cham-Zug bay. The Lorze as the main feeder river empties its waters into the lak ...

in Switzerland and described in 2021.

Ecology

"''Ca''. A. ciliaticola" is an obligate

endosymbiont An ''endosymbiont'' or ''endobiont'' is any organism that lives within the body or cells of another organism most often, though not always, in a mutualistic relationship. (The term endosymbiosis is from the Greek: ἔνδον ''endon'' "within" ...

of an

anaerobic Anaerobic means "living, active, occurring, or existing in the absence of free oxygen", as opposed to aerobic which means "living, active, or occurring only in the presence of oxygen." Anaerobic may also refer to: * Anaerobic adhesive, a bonding a ...

freshwater

from the class Plagiopylea. Endosymbiont contains highly reduced genome with 0.29 Mbp while substantial fraction of this genome is dedicated to energy production. "''Ca''. A. ciliaticola" contains complete gene set for

and is thus the first observed obligate

with such pathway. Extensive genetic potential for energy metabolism hints that the main function of the endosymbiont is to generate ATP and provide it to its

host. ''Ca''. A. ciliaticola thus have functions which are similar to

mitochondria A mitochondrion (; ) is an organelle found in the Cell (biology), cells of most Eukaryotes, such as animals, plants and Fungus, fungi. Mitochondria have a double lipid bilayer, membrane structure and use aerobic respiration to generate adenosi ...

, although it is not derived from a mitochondrial line of descent. It provokes question if also some other

eukaryota Eukaryotes () are organisms whose Cell (biology), cells have a cell nucleus, nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the ...

are using

Prokaryote A prokaryote () is a single-celled organism that lacks a nucleus and other membrane-bound organelles. The word ''prokaryote'' comes from the Greek πρό (, 'before') and κάρυον (, 'nut' or 'kernel').Campbell, N. "Biology:Concepts & Connec ...

s to transfer electrons to non-canonical electron acceptors such as in the case of

References

{{Taxonbar, from=Q106577984 Gammaproteobacteria Ciliates Anaerobic respiration Anaerobes 2021 in science

Ecology

Other links

References