Hydrogenosome

from Wikipedia, the free encyclopedia

Hydrogenosomes (from English hydrogen , "hydrogen") are organelles that occur in some trichomonads , ciliates (Ciliophora), potty mushrooms (Chytridiomycota) and some corset animals (Loricifera, including Spinoloricus ) instead of mitochondria and enable survival under anaerobic conditions. The approximately 1 µm organelles were described for the first time in 1973. In electron microscopic specimens, hydrogenosomes appear as spherical, membrane-bound, electron-dense organelles.

Descent and system

All hydrogenosomes are likely derived from a mitochondrion. In almost all cases, the genome including the ribosomes was lost. Only in the hydrogenosomes of the ciliate Nyctotherus ovalis is a small genome with ribosomes still present. It therefore represents an intermediate form ( missing link ) in the evolution from mitochondrion to hydrogenosome. The two organelles show different similarities: They are surrounded by two membranes, produce adenosine triphosphate (ATP), occur in many copies and divide without synchronization during the entire cell cycle .

Together with the mitosomes , mitochondria and hydrogenosomes are classified as " mitochondria-related organelles" ( English mitochondrion-related organelles , MROs). These also include the anaerobic and DNA- free organelles of Henneguya salminicola (alias H. zschokkei , Myxozoa )

physiology

Model for ATP synthesis in hydrogenosomes.
Abbreviation: CoA = Coenzyme A

In contrast to the mitochondria, the hydrogenosomes lack their own genome , ribosomes (exception: N. ovalis ), respiratory chain , cytochromes , F o F 1 -ATPase , citric acid cycle , oxidative phosphorylation and cardiolipin . While mitochondria only operate aerobic respiration, hydrogenosomes enable fermentation under anaerobic and aerobic conditions (Fig. 1). The first substrate for the substrate chain phosphorylation , from which ATP emerges, is pyruvate , the end product of the glycolysis that takes place in the cytosol . The phosphorylation of adenosine diphosphate (ADP) to ATP is catalyzed by succinyl-CoA synthetase . The by-products of ATP synthesis under anaerobic conditions include acetate and hydrogen, which gives the hydrogenosomes their name. Under aerobic conditions, hydrogen peroxide is likely to be produced instead of hydrogen .

See also

Individual evidence

  1. Andy Coghaln: Zoologger: The mud creature did lives without oxygen on: NewScientist from 7 April 2010
  2. Roberto Danovaro et al. : The first metazoa living in permanently anoxic conditions , in: BMC Biology, Volume 8, No. 30, April 6, 2010, doi: 10.1186 / 1741-7007-8-30
  3. ^ DG Lindmark, M. Müller: Hydrogenosome, a cytoplasmic organelle of the anaerobic flagellate Tritrichomonas fetus , and its role in pyruvate metabolism. In: Journal of Biological Chemistry . Volume 248, 1973, pp. 7724-7728.
  4. Michael Mielewczik, Heinz Mehlhorn, Saleh Al-Quraishy, ​​E. Grabensteiner, M. Hess: Transmission electron microscopic studies of stages of Histomonas meleagridis from clonal cultures . In: Parasitology Research . tape 103 , no. 4 , September 1, 2008, ISSN  0932-0113 , p. 745 , doi : 10.1007 / s00436-008-1009-1 ( springer.com [accessed May 5, 2018]).
  5. ^ Eugene H. Johnson, Jeffrey J. Windsor, C. Graham Clark: Emerging from Obscurity: Biological, Clinical, and Diagnostic Aspects of Dientamoeba fragilis . In: Clinical Microbiology Reviews . tape 17 , no. 3 , July 1, 2004, ISSN  0893-8512 , p. 553-570 , doi : 10.1128 / CMR.17.3.553-570.2004 , PMID 15258093 , PMC 452553 (free full text) - ( asm.org [accessed May 5, 2018]).
  6. Marlene Benchimol, Cezar Antonio Elias, Wanderley De Souza: Tritrichomonas fetus: Ultrastructural localization of calcium in the plasma membrane and in the hydrogenosome . In: Experimental Parasitology . tape 54 , no. 3 , December 1982, ISSN  0014-4894 , pp. 277-284 , doi : 10.1016 / 0014-4894 (82) 90036-4 .
  7. Brigitte Boxma, Rob M. de Graaf, Georg WM van der Staay, Theo A. van Alen, Guenola Ricard, Toni Gabaldon, Angela HAM van Hoek, Seung Yeo Moon-van der Staay, Werner JH Koopman, Jaap J. van Hellemond , Aloysius GM Tielens, Thorsten Friedrich, Marten Veenhuis, Martijn A. Huynen, Johannes HP Hackstein: An anaerobic mitochondrion that produces hydrogen . In: Nature . tape 434 , no. 7029 , February 3, 2005, p. 74-79 , doi : 10.1038 / nature03343 .
  8. A. Akhmanova, F. Voncken, T. van Alen et al : A hydrogenosome with a genome . In: Nature . 396, No. 6711, December 1998, pp. 527-528. doi : 10.1038 / 25023 . PMID 9859986 .
  9. Jan Osterkamp: First animal without breathing and mitochondria , on: Spektrum.de from February 25, 2020
  10. See also: H. nuesslini ; Peacock Wrasse§ Threats ( H. tunisiensis )
  11. Tel Aviv University researchers discover unique non-oxygen breathing animal , on: EurekAlert! from February 25, 2020
  12. M. Müller, DG Lindmark: Respiration of hydrogenosomes of Tritrichomonas fetus. II. Effect of CoA on pyruvate oxidation. In: Journal of Biological Chemistry . tape 253 , no. 4 , January 25, 1978, p. 1215-1218 ( online [accessed September 14, 2010]).
  13. Marlene Benchimol, Flávio Engelke: Hydrogenosome behavior during the cell cycle in Tritrichomonas fetus . In: Biology of the Cell . tape 95 , no. 5 , June 2003, p. 283-293 , doi : 10.1016 / S0248-4900 (03) 00060-1 .