Unique non-oxygen breathing animal discovered: The tiny relative of the

Patrick · February 26, 2020, 12:23am

cwhenderson · February 27, 2020, 3:14am

It’ll be interesting to see what turns up with further research on this animal. Maybe entirely glycolytic metabolism?

stlyankeefan · February 27, 2020, 3:36am

Loriciferans are also anaerobic.Scientists discover first multicellular life that doesn't need oxygen

swamidass · February 27, 2020, 3:49am

But this is an “animal” without mitochondrion! This isn’t merely an anarobe.

stlyankeefan · February 27, 2020, 3:52am

Loriciferans also don’t have mitochondria. The use unique organelles known as hydrogenosomes.

ncbi.nlm.nih.gov

A common evolutionary origin for mitochondria and hydrogenosomes.

ET Bui, PJ Bradley and PJ Johnson, Proceedings of the National Academy of Sciences of the United States of America, Sep 1996 03

Trichomonads are among the earliest eukaryotes to diverge from the main line of eukaryotic descent. Keeping with their ancient nature, these facultative anaerobic protists lack two "hallmark" organelles found in most eukaryotes: mitochondria and peroxisomes. Trichomonads do, however, contain an unusual organelle involved in carbohydrate metabolism called the hydrogenosome. Like mitochondria, hydrogenosomes are double-membrane bounded organelles that produce ATP using pyruvate as the primary substrate. Hydrogenosomes are, however, markedly different from mitochondria as they lack DNA, cytochromes and the citric acid cycle. Instead, they contain enzymes typically found in anaerobic bacteria and are capable of producing molecular hydrogen. We show here that hydrogenosomes contain heat shock proteins, Hsp70, Hsp60, and Hsp10, with signature sequences that are conserved only in mitochondrial and alpha-Gram-negative purple bacterial Hsps. Biochemical analysis of hydrogenosomal Hsp60 shows that the mature protein isolated from the organelle lacks a short, N-terminal sequence, similar to that observed for most nuclear-encoded mitochondrial matrix proteins. Moreover, phylogenetic analyses of hydrogenosomal Hsp70, Hsp60, and Hsp10 show that these proteins branch within a monophyletic group composed exclusively of mitochondrial homologues. These data establish that mitochondria and hydrogenosomes have a common eubacterial ancestor and imply that the earliest-branching eukaryotes contained the endosymbiont that gave rise to mitochondria in higher eukaryotes.

Joe_Felsenstein · February 27, 2020, 6:44am

Loriciferans are multicellular animals. Trichomonads are not loriciferans and not multicellular.

stlyankeefan · February 27, 2020, 1:05pm

Yes, but loriciferans also use hydrogenosomes.