Evolutionary Insights into Membrane Lipid Biosynthesis in Archaea and Bacteria
This text delves into the evolutionary history of Archaea and Bacteria, focusing on membrane lipid biosynthesis. It outlines key steps in the formation of unique lipid structures that distinguish these domains, emphasizing the transition from ester to ether lipids in Archaea. The role of LUCA (Last Universal Common Ancestor) is discussed regarding its genetic makeup and the evolutionary significance of viruses in cellular development. The text challenges traditional prokaryotic classifications and presents novel insights into the complex interplay of genetics and evolution among these microorganisms.
Evolutionary Insights into Membrane Lipid Biosynthesis in Archaea and Bacteria
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sn-glycerol 3-phosphate fosfolipidy sn-glycerol 1-phosphate
Archebakterie (Archaea) – doména s unikátním složením membrán , Eukaryota and Eukaryota
Figure 1.Committing steps in the biosynthesis of membrane lipids. The "primary divide" separating Archaea from Bacteria and Eukarya is outlined. Glansdorffetal 2008 Biology Direct 2008, 3:29
Luis Villareal: Can viruses make us human? http://cvr.bio.uci.edu/downloads/03_villa_canvir.pdf (scifi: Greg Bear: Darwinovo rádio) - zkoušet to nebudu
(7) Archaea arose by reductive evolution under selection for adaptation to high temperatures; this entailed the replacement of sn1,2 ester fatty acid lipid by sn2,3 ether isoprenoid lipids in the cell membrane, without major enzymatic reconversion. (8) Bacteria arose by reductive evolution; secondary, convergent adaptations to thermophily entailed the formation of a variety of membrane lipids, often with ether bonds, but still with a sn1,2 stereoconfiguration.
(9) LUCA wasgeneticallyredundant; thereforethedifferentiallossofparalogous gene copies in different lines ofdescentis a predictedsource ofphylogeneticdiscrepancieswithrespect to the SSU-rRNAtree.
(3) LUCA was a protoeukaryote, with a RNA genome inherited from its progenote ancestor. This RNA LUCA was in a metabolically and morphologically heterogeneous community, constantly shuffling around genetic material. Part of it was phagotrophic. LUCA remained an evolutionary entity, though loosely defined and constantly changing, as long as this promiscuity lasted. (4) The RNA to DNA transition took place independently in different lineages of this community; the intervention of viruses appears a likely mechanism. This process led to the emergence of the three Domains.
(1) Theword "prokaryote" has becomeinadequateandmisleading. (2) Eukaryoticidiosyncrasiesand a reappraisalofphylogeny do not support thenotionof a prokaryotic LUCA nor ofprokaryoticancestorsoftheeukaryotic cell body. Theorderofbranching in theuniversaltree has no bearing on thecellulararchitectureof LUCA.
E.V. Koonin: vývoj buněk z pradávného světa virů Např. Biology Direct 1, 29, 2006 http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1594570&blobtype=pdf Biological big bang Biol. Direct 2,21,2007
Bakteriální biosféra • sdílený genový pool → Bakteriální promiskuita– transdukce, transformace, konjugace • sdílené signály → quorumsensing • mezibuněčná hmota → konsorcia, povlaky, stromatolity etc.
The greatest surprise resulting from the application of genomics tobacteriology was the extent of genomic variability within many bacterial species. Bacterial pathogenomics Mark J. Pallen1 & Brendan W. Wren NATURE|Vol 449|18 October 2007|
Origins of Highly Mosaic Mycobacteriophage Genomes Part of the Che8 genome shown in (A) is also shared by phage Corndog. The 378 bpshared regions are 100% identical and theirjoint appearance in these phages must bederived from a recent evolutionary event. Cell, Vol. 113, 171–182, April 18, 2003
Luis Villareal: Can viruses make us human? http://cvr.bio.uci.edu/downloads/03_villa_canvir.pdf (scifi: Greg Bear: Darwinovo rádio) - zkoušet to nebudu Viry v prostředí: obrovská diverzita (statisíce) „virioplankton: 106-109 částic/ml metagenomika Angly: PLoS Biology 4, e368, 2006
