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Discover the Microbes Within! The Wolbachia Project

Discover the Microbes Within! The Wolbachia Project. Real-world Research in the Classroom. Discover the Microbes Within! The Wolbachia Project. 1,000,000,000,000,000,000 insects on the planet Insects present on earth for ~500 MY 85% of all animal species are insects (1-30 million species)

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Discover the Microbes Within! The Wolbachia Project

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  1. Discover the Microbes Within! The Wolbachia Project Real-world Research in the Classroom

  2. Discover the Microbes Within!The Wolbachia Project • 1,000,000,000,000,000,000 insects on the planet • Insects present on earth for ~500 MY • 85% of all animal species are insects (1-30 million species) • 20% of all insect species harbor heritable symbionts called Wolbachia • Scientists cant discover them all on their own. • YOU ARE OUR BIGGEST ASSET TO SCIENTIFIC DISCOVERY AND REAL RESEARCH!

  3. What is symbiosis? • The living together of dissimilar organisms (de Bary 1859) • Often for mutual benefit, but also parasitism and commensalism • Endosymbiosis is when one organism lives and replicates inside another one

  4. Vertically-transmitted(i.e., Inherited) Symbionts

  5. Insect egg with symbiotic bacteria Insect egg Credit: Michael Clark & Seth Bordenstein

  6. Ways that vertically transmitted microbes can increase in frequency • Increase host survival & reproduction (mutualism) • Very common • Why might vertical transmission be associated with mutualistic effects on hosts? • Most famous cases are the lineages leading to organelles • Mitochondria evolved from the alpha-Proteobacteria about 2 billion years ago • Chloroplasts evolved from cyanobacteria about 1 billion years ago

  7. Must heritable symbionts always be beneficial?

  8. Reproductive Parasites

  9. Distortion of the sex-ratio Dead end Asymmetric (Uniparental) Inheritance

  10. Wolbachia are Infectious Widowmakers! Male-Killing Parthenogenesis Feminization Reproductive Parasitism: each of these reproductive distortions leads to more infected females in the insect host species

  11. Phylogeny of Wolbachia NATURE REVIEWS | microbiology Vol OCT 2008, p741

  12. Wolbachia Induced Phenotypes NATURE REVIEWS | microbiology Vol OCT 2008, p741

  13. Cytoplasmic Incompatibility (CI) Testes Late prophase Prometaphase Embryo Metaphase Telophase Wolbachia Courtesy of U. Tram Host CI X x = Wolbachia-infected offspring x = Uninfected offspring x = Wolbachia-infected offspring x =

  14. Wolbachia-to-host lateral gene transfer in Drosophila ananassae NATURE REVIEWS | microbiology Vol OCT 2008, p741

  15. Imagine… …physicians across the United States…documenting similar events. In each case, an unfertilized egg in a woman had spontaneously begun to develop, ultimately producing a healthy female baby. One young researcher, who had analyzed the timing and locales of the virgin births, suggested a spreading infection might be causing the incidents. The Federal Centers for Disease Control and Prevention in Atlanta quickly dismissed the idea, calling it "ridiculous." Several months later came a well-publicized report in the Journal of the American Medical Association concluding that the number of infertile couples was rising rapidly worldwide. The international uproar intensified when physicians began to observe another reproductive curiosity: Some newborns that were genetically male appeared to be female. One week, the New England Journal of Medicine and the National Enquirer ran articles with the headline, "Is this the end of mankind, or just men?" Science fiction? Definitely. For many insect species and other arthropods, however, the truth can be as strange as fiction when bacteria known as Wolbachia are around. By JOHN TRAVIS Undesirable Sex Partners Bacteria manipulate reproduction ofinsects and other species

  16. The Wolbachia Pandemic

  17. The Wolbachia Pandemic Insects (at least 20% !) Filarial nematodes Crustaceans (family Onchocercidae) Chelicerates 2-6 million insect species are infected with Wolbachia!! Arthropods Nematodes

  18. Number of scientific papers with Wolbachia in title PCR detection of Wolbachia in ~20% of all insects Nobel prize awarded for PCR

  19. How Important Are Wolbachia?

  20. Human Health: Wolbachia may help control the transmission of arthropod-borne diseases (Malaria, Dengue fever, Filariasis, Trypanosomiasis, West Nile, Chagas) Does Not Transmit Disease Transmits Disease Reinfect vector with transgenic symbiont Isolate and culture symbiont Transform symbiont Anti-pathogen gene

  21. Drive via Cytoplasmic Incompatibility Male Female Progeny X None (Incompatible) X X X

  22. Population Replacement Transmits Disease Does Not Transmit Disease

  23. Human Health: Bill and Melinda Gates Foundation

  24. Wolbachiaare Chemotherapy Targets for Curing River Blindness & Elephantiasis Caused By Filarial Nematodes Onchocerca volvlulus Untreated 11 months post-treatment Horeauf et al, 2003

  25. Tissue Nematode (Roundworm): Onchocerca volvulus and River Blindness • Transmitted by biting black flies • Larvae develop into adults in subcutaneous tissues • Adult females migrate via the blood to the eyes, provoking inflammatory reactions • Coinfection with Wolbachia bacteria causes river blindness • Treatment: tetracycline and ivermectin

  26. Overview of Onchocerciasis • River blindness is the symptomatic stage of a filarial infection • It is a painful and debilitating disease. • 18 million people in Africa are infected

  27. Overview of Onchocerciasis • Symptoms include: visual impairment, rashes, lesions, intense itching, depigmentation, inflammation of lymph nodes, and general debilitation.

  28. Overview of Onchocerciasis • Disease is the result of infection by the parasitic worm, Onchocerca volvulus. • Females produce millions of microfilariae that migrate through the body and cause a manifestation of symptoms

  29. Overview of Onchocerciasis • Simulans spp. (black flies) are vectors • Female black flies require a blood meal prior to egg laying • Microfilariae are taken in with infected blood • Transfer takes place when the fly bites uninfected person

  30. CDC/DPD Summary Report 2001 • Black flies are infected with Wolbachiabacteria • Worldwide distribution • Infection rates have been found to be up to 76% of insects in some regions • Also found in millipedes, crustaceans, and mites • Wolbachia is passed horizontally and vertically

  31. Lancet 2005; 365: 2116–21

  32. Tissue Nematode (Roundworm): Wuchereria bancrofti • Tropical infection spread by mosquitoes • Vector deposits larvae which move into lymphatics and develop • Chronic infection causes blockage of lymphatic circulation and elephantitis, massive swelling in the extremities

  33. Tissue Nematode (Roundworm): Filariasis due to W. bancrofti • Endemic in central Africa, Mediterranean coast, parts of Asia (China, Korea, Japan, the Philippines) • Blood specimens may show microfilariae • Acute symptoms include: fever, lymphangitis/lymphadenitis • Result of inflammatory response to molting adolescent worms and dead adults in lymphatic vessels • May involve any part of body, blocking lymphatic system

  34. Tissue Nematode (Roundworm): Elephantitis

  35. Elephantiasis: Wucheria bancrofti

  36. How do YOU discover the Wolbachia within?

  37. Integrated Set of Lab ExercisesFrom Organisms to Molecules and Back! Lab 1 - Insect Identification (Biodiversity) Lab 2 - Isolation of Insect and Wolbachia DNA (Molecular Biology) Lab 3 - PCR of Wolbachia 16S rDNA (Molecular Biology) Lab 4 - Presence/Absence of Amplicon (Molecular Biology) Lab 5 - Evolutionary Sequence Analysis (Bioinformatics)

  38. Features of These Labs • Original Research in Lab Exercises • YOU can make new discoveries • Integrates across Science • Biodiversity -> Molecular -> Evolution • Integrates Science and Technology • Covers Emerging Fields • Microbial diversity, Bioinformatics, Molecular Phylogeny

  39. Ephemeroptera mayflies; 2,000 species Discover the Microbes Within: The Wolbachia Project Lab 1: Insect Identification Hemiptera aphids; 67,500 species Coleoptera beetles; 370,000 species Collembola spring tails; 6,000 species Diptera flies; 120,000 species Lepidoptera butterflies, moths, skippers; 140,000 species Orthoptera grasshoppers, crickets, katydids; 17,000 species Odonata dragonflies, damselflies; 5,000 species Dermaptera earwigs; 1,200 species Hymenoptera bees, wasps, ants; 108,000 species Isoptera termites; 1,900 species Dictypotera cockroaches and mantids; 6,000 species

  40. EXTRACT DNA FROM YOUR SAMPLES WHY? Discover the Microbes Within: The Wolbachia Project Lab 2: DNA Extraction Infected sample (+): Uninfected Sample (-) Insect Insect Mitochondria Mitochondria WOLBACHIA -

  41. Discover the Microbes Within: The Wolbachia Project Lab 3: Polymerase Chain Reaction

  42. Discover the Microbes Within: The Wolbachia Project Lab 4: Gel Electrophoresis

  43. Discover the Microbes Within: The Wolbachia Project Lab 4: Gel Electrophoresis + + + + + + + + + + + + + + + + + + + + +

  44. Discover the Microbes Within: The Wolbachia Project Lab 5: Sequence Analysis • NCBI • BLAST • No programming skills required!

  45. When It all comes together, it looks like this!

  46. High School MBL ATGCGC Primers, Insect controls,

  47. Where Does Your Data Go? To… Consequences • Class reports • Peers, family, teachers, research scientists • Online database (website repository for your data) • New discoveries • Collaborations between research scientists and high schools • Summer “envisionships” • Professional meetings • Professional societies • Journal publications

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