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Three Bacterial Lifestyles. Extracellular. Facultative. Obligate (Horizontally- Transmitted). Free-living world. Intracellular world. Obligate (Horizontally- Transmitted). Obligate (Vertically -transmitted). Facultative. Exposure to novel gene pools. High. Low.
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Three Bacterial Lifestyles Extracellular Facultative Obligate (Horizontally- Transmitted) Free-living world Intracellular world Obligate (Horizontally- Transmitted) Obligate (Vertically -transmitted) Facultative Exposure to novel gene pools High Low
Obligate Intracellular Bacteria That Host-Switch Chlamydia Rickettsia
Maternal transmission of obligate intracellular bacteria Bacterial symbionts Insect nuclei Insect ovariole Bacterial symbionts
Does transmission of obligate intracellular bacteria affect mobile DNA content?
Horizontally-transmitted symbionts have more species with mobile DNA than vertically-transmitted species Horizontally-transmitted Vertically-transmitted • 31/32 species with Mobile DNA • 3/8 species with Mobile DNA Fisher’s exact test, P = 0.0005 Newton & Bordenstein 2011
How are Mobile DNAs Transmitted in Obligate Intracellular Bacteria ? Chlamydia Rickettsia
Wolbachia = One of the great pandemics in the history of life Phylum Arthropoda(parasitic) • Up to66% ofarthropodspecies (which comprise 85% of all animal spp.) Phylum Nematoda (mutualistic) • 90% of filarial nematode species Homo sapiens(pathogenic) • River Blindness • Lymphatic filariasis • The cause is Wolbachia, not the nematode
Wolbachia:Mutualist and Parasite Required for insect oogenesis (Dedeine et al. 2001) Parthenogenesis in wasps Mutualism Reproductive parasitism Male-killing in insects Required for nematode fertility and larval development Feminization in isopods Cytoplasmic incompatibility in arthropods
Cytoplasmic Incompatibility (CI) Testes Late prophase Prometaphase Embryo Metaphase Telophase Wolbachia Host Courtesy of U. Tram CI X x = Wolbachia-infected offspring x = Uninfected offspring x = Wolbachia-infected offspring x =