Boreskov

OP‐14WOLBACHIA – A NASCENT NEW ORGANELLE OF THE EUKARYOTIC CELLIlinsky Yu.Yu. 1,2 , Zakharov I.K. 1,21 Institute of Cytology and Genetics SB RAS, Novosibirsk, Russia2 Novosibirsk State University, Novosibirsk, Russiapaulee@bionet.nsc.ruThe eukaryotic cell has been associated at its very origin with with symbiosis.Evolutionary progress post biochemical evolution of eubacteria and archaea lead toassociation of some bacteria into an united cytoplasmic system. Division of the cytoplasmicspace into compartments made it possible for the new cell to protect genetic informationfrom mutagenic factors, to restraint horizontal transmission among cells, to intensifyenergetic processes as well as to alter sizes and forms of the cells. However, the moment ofthe eukaryotic cell appearance in evolution of the Earth biosphere has been shrouded inmystery, with the principal absent of palaeontolological evidence. Can new compartmentsalike mitochondria, plastids or nucleus appear in the modern eukaryotic cell?At present a lot of examples of symbiotic associations are known and they can actuallydemonstrate, with certain reservations made, examples of evolutionary process oforganellogenesis. Most of these facts relate to intracellular bacteria‐invertebrata hostassociations, an in the majority of cases these bacteria provide the host with nutrition (1).The γ‐proteobacteria Buchera – aphid system exemplifies one of the first and most ancientsymbioses (~200 Mya) that were investigated. There is Buchera population in specializedcells of the host, bacteriocytes; a functional role of Buchera consist in biosynthesis ofessential amino acids to the host. Buchera has lost autonomy due to of the loss of manygenes and biochemical pathways. The bacteria are transmitted via eggs and thus Buchera ispassed on to following generations of the aphid. The host genome is responsible for thecontrol of expression of certain bacterial genes and cellular processes, i.e. the size of thebacterial population. In other words, the host has a biofactory and runs it.There are a lot of other examples of bacteria‐animal intercellular symbiotic assosiationswhere we can observe the whole gradual transition from parasitic to obligate mutualisticinteractions of the organisms (1). Distribution of the most bacteria within the host taxon isrestricted by the family or genus rank.An ‐proteobacteria Wolbachia is an unique phenomenon amonf intracellular bacteriaas it forms persistent symbiotic interrelations at least within two phyla: Nematoda andArthropoda. The origin time of these genus bacteria has been estimated basing on 16SrRNA52