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Eukaryotic Evolution and Earth History: Mitochondria's Role Unveiled

Explore the fascinating connection between eukaryotes, mitochondria, and Earth's history, from origin theories to unique metabolic pathways. Discover the significance of anaerobic mitochondria and the impact of Proterozoic ocean chemistry. Uncover the common features and diversity among hydrogenosomes, mitosomes, and mitochondria, shedding light on the evolution of eukaryotic cells. Delve into the geochemical history of Earth and its influence on cellular adaptations, highlighting the intricate relationship between oxygenation, metabolism, and cellular evolution.

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Eukaryotic Evolution and Earth History: Mitochondria's Role Unveiled

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  1. Marek MentelPrednáška, Gymnázium GJH, marec 2012

  2. Are eukaryotes all about oxygen? ...and what Earth history has to do with it? Marek MentelPrednáška, Gymnázium GJH, marec 2012

  3. Lecture content • What are eukaryotes - eukaryotes specific features • Eukaryotes origin theories • Mitochondria types i.e. aerobic and anaerobic mitochondria hydrogenosomes mitosomes (cryptons) aerobic • Energetic metabolism of individual mitochondria forms i.e. respiration anaerobic fermentation chemolithotrophy • Mitochondria origin in the context of Earth geochemistry changes

  4. Cytology - Prokaryotic & Eukaryotic cells comparison

  5. Cytology - Eukaryotic cells specific features Nucleus/EndoMembrane system/ Golgi apparatus Cytoskeleton /Flagella & Cilia Endocytosis e.g. Phagocytosis Mitosis Sex – Meiosis & Fertilization Mitochondria Plastids Peroxisome Linear chromosomes (centromere, telomere, telomerase) Spliceosome (spliceosomal Introns splicing-mRNA export coupling)

  6. Habitats and Energetics - Prokaryotic & Eukaryotic cells versatility comparison anaerobic respiration aerobic respiration !! not true for eukaryotes !!

  7. Eukaryotic cells origin theories review Phagocytosis first / Mitochondria late view Mitochondria first/ Phagocytosis late view

  8. Eukaryotic cells origin theories - prokaryotes within prokaryotes plausibility Mealybug Planococcus citri endosymbiotic γ-proteobacteria within ß-proteobacteria

  9. Eukaryotic cells origin theories - ox-tox hypothesis

  10. Eukaryotic cells origin theories- hydrogen hypothesis

  11. Aerobic mitochondria • Biosynthetic pathways: Heme synthesis Fe-S synthesis Ubiquinone synthesis • Metabolism: Amino acids Carbohydrates Nucleotide & Krebs cycle Lipid • Energetics: aerobic respiration– oxidative phosphorylation aerobic respiration

  12. (facultative) Anaerobic mitochondria • Unicellular protists & Metazoa: Ciliates nitrate, nitrite • Fungi nitrate, nitrite, sulfur • Nematodes fumarate • Plathelminthsfumarate • Snails fumarate • Bivalves fumarate • anaerobic respiration Chemolithotrophic mitochondria • Metazoa: Bivalves • Polychaete worm • Crustaceans • chemolithotrophy – inorganic electron donor (S2-, HS-, H2S)

  13. Hydrogenosomes and Mitosomes (Crypton) - MLOs • Unicellular anaerobes: • Parabasalids(Trichomonas) • Ciliates (Nyctotherus) • Chytridiomycete fungi (Neocallimastix) • Amoeboflagellate(Psalteriomonas) • Stramenopile (Blastocystis) fermentation – substrate-level phosphorylation Hydrogenosome Diplomonads(Giardia) Entamoebids(Entamoeba) Microsporidia (Encephalitozoon) Apicomplexan (Cryptosporidium) no energy metabolism Mitosome • Mitochondria, Hydrogenosomes, Mitosomescommon features: double membrane protein targeting / import iron-sulfur clusters synthesis mitochondrial carrier family proteins

  14. Hydrogenosomes and Mitosomes structure hydrogenosome with cristae - N.ovalis mitosome - Giardia & Methanogen mitochondria hydrogenosome without cristae & EReticulum mitosome - Cryptosporidium Neocallimastix patriciarum

  15. (facultative) Anaerobic mitochondria – Fasciola hepatica

  16. Anaerobic mitochondria / Hydrogenosome – Nyctotherusovalis

  17. Hydrogenosome – Piromycessp. E2

  18. Mitosome – Giardia intestinalis

  19. Earth history - Geological TimeScales eukaryotes origin P - Pleistocene Holocene

  20. Geochemical history of Earth – atmosphere oxygenation eukaryotes origin

  21. Earth history – significant lag in oceans oxygenation & Canfield oceans chemistry slight atmosphere oxygenation continents weathering sulfate-reducing bacteria radiation

  22. Geochemical history of Earth – significant lag in oceans oxygenation & Canfield oceans eukaryotes origin Anbar & Knoll, 2002

  23. Earth history – significant lag in oceans oxygenation & Canfield oceans eukaryotes origin

  24. Eukaryotic anaerobes & Proterozoic ocean chemistry Dietrich, 2006 Mentel & Martin, 2008

  25. Origins of mitochondria, hydrogenosomes and mitosomes Glycolysis - backbone of energy metabolism in Eukaryotes Martin, 2001

  26. Metabolically flexible mitochondria – Arenicola marina

  27. Take home messages: O • EukaryotesandMitochondria 2 • Mitochondria: aerobic anaerobic chemolithotrophic hydrogenosomes – not uniform mitosomes oxidative phosphorylation • genome • cristae substrate-level phosphorylation no energy metabolism • Anaerobic mitochondria& eukaryotic anaerobes make sense in light of Proterozoic ocean chemistry Obligate aerobes like ourselves seems to represent specialized adaptation to recently oxygenated habitats

  28. Take home messages: • geochemical Earth history (changing Earth) what makes mitochondria an essential compartment for eukaryotic cell – where is the limit for its reduction ? & interconnection Eukaryotes evolution • mitosomes • cryptic mitochondria (Cryptosporidium parvum) • not energy metabolism • mitosomes (Giardia intestinalis (syn. lamblia)) • cryptic mitochondria (Cryptosporidium parvum) • mitochondria (yeast) • iron-sulfur cluster biosynthesis

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