生物谷報(bào)道： 氫化酶體是產(chǎn)生ATP和氫的細(xì)胞器官,，并且在不同的真核生物中發(fā)現(xiàn),，如厭氧性鞭毛蟲、chytridiomycete真菌,、纖毛蟲,。盡管所有器官都能產(chǎn)生氫,，但是這些生物中氫化酶體在結(jié)構(gòu)和代謝上非常不同，就像線粒體亦存在較大差別,。這些區(qū)別導(dǎo)致生物演化上的大量的爭論,。這兒我們就生長在蟑螂尾腸的厭氧性纖毛蟲Nyctotherus ovalis的氫化酶體，它保持著基本的基因組編碼的線粒體的電子傳遞體,。系統(tǒng)發(fā)生分析揭示那些需氧性纖毛成蛋白質(zhì)簇和那些同簇體,。詳見如下：

Change in the air

    Hydrogenosomes are simple organelles found in anaerobic protists and fungi. They are double-membraned and produce ATP and hydrogen, hence suggestions that they are anaerobic derivatives of mitochondria. An alternative view suggests that mitochondria and hydrogenosomes arose from a common ancestor, a facultatively anaerobic bacterium. The discovery of a novel hydrogenosome in Nyctotherus ovalis, a ciliate that lives in the gut of cockroaches, further complicates this debate. It is unique among known hydrogenosomes because, just like a mitochondrion, it retains its own genome. This 'missing link' between hydrogenosomes and mitochondria also has remnants of an electron transport chain characteristic of an aerobic lifestyle.

Nature 434, 74 - 79 (03 March 2005); doi:10.1038/nature03343

An anaerobic mitochondrion that produces hydrogen

BRIGITTE BOXMA1,*, ROB M. DE GRAAF1,*, GEORG W. M. VAN DER STAAY1,*, THEO A. VAN ALEN1, GUENOLA RICARD2, TONI GABALDÓN2, ANGELA H. A. M. VAN HOEK1,†, SEUNG YEO MOON-VAN DER STAAY1, WERNER J. H. KOOPMAN3, JAAP J. VAN HELLEMOND4, ALOYSIUS G. M. TIELENS4, THORSTEN FRIEDRICH5, MARTEN VEENHUIS6, MARTIJN A. HUYNEN2 & JOHANNES H. P. HACKSTEIN1

1 Department of Evolutionary Microbiology, Faculty of Science, Radboud University Nijmegen, Toernooiveld 1, NL-6525 ED Nijmegen, The Netherlands
2 Centre for Molecular and Biomolecular Informatics,
3 Microscopical Imaging Centre and Department of Biochemistry, Nijmegen Centre of Molecular Life Sciences (NCMLS), Radboud University Nijmegen Medical Centre, NL-6500 HB Nijmegen, The Netherlands
4 Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, PO Box 80176, NL-3508 TD Utrecht, The Netherlands
5 Albert-Ludwigs-Universität, Institut für Organische Chemie und Biochemie, Albertstrasse 21, D-79104 Freiburg i. Br., Germany
6 Department of Eukaryotic Microbiology, Groningen University, PO Box 14, NL-9750 AA Haren, The Netherlands
* These authors contributed equally to this work
† Present address: RIKILT, Institute of Food Safety, Bornsesteeg 45, NL-6708 PD Wageningen, The Netherlands

Correspondence and requests for materials should be addressed to J.H.P.H. ([email protected]).
Sequences have been deposited at the EMBL database under accession numbers AF480921, AJ871267, AJ871313–AJ871361, AJ871573–AJ871576, AY608627, AY608632–AY608634, AY616150–AY616152, AY619980, AY619981, AY623917, AY623919, AY623925, AY623926, AY628683, AY628684, AY628688.

First Paragraph:

    Hydrogenosomes are organelles that produce ATP and hydrogen, and are found in various unrelated eukaryotes, such as anaerobic flagellates, chytridiomycete fungi and ciliates. Although all of these organelles generate hydrogen, the hydrogenosomes from these organisms are structurally and metabolically quite different, just like mitochondria where large differences also exist. These differences have led to a continuing debate about the evolutionary origin of hydrogenosomes. Here we show that the hydrogenosomes of the anaerobic ciliate Nyctotherus ovalis, which thrives in the hindgut of cockroaches, have retained a rudimentary genome encoding components of a mitochondrial electron transport chain. Phylogenetic analyses reveal that those proteins cluster with their homologues from aerobic ciliates. In addition, several nucleus-encoded components of the mitochondrial proteome, such as pyruvate dehydrogenase and complex II, were identified. The N. ovalis hydrogenosome is sensitive to inhibitors of mitochondrial complex I and produces succinate as a major metabolic end product—biochemical traits typical of anaerobic mitochondria. The production of hydrogen, together with the presence of a genome encoding respiratory chain components, and biochemical features characteristic of anaerobic mitochondria, identify the N. ovalis organelle as a missing link between mitochondria and hydrogenosomes.