wolbachia
DESCRIPTION
Wolbachia. Google images. TEM; Google images. Concepts. Endosymbioses Host manipulation Co-evolution. Google images. History. One of the most infectious bacterial genera on earth Endosymbionts First discovered in 1924 in insects; largely unknown until the 1990s (Evade detection) - PowerPoint PPT PresentationTRANSCRIPT
Wolbachia
Google images TEM; Google images
Concepts
• Endosymbioses
• Host manipulation
• Co-evolutionGoogle images
History
• One of the most infectious bacterial genera on earth
• Endosymbionts • First discovered in 1924 in insects; largely
unknown until the 1990s (Evade detection)• Now known to be in nematodes• Applications for bio-control and treatment of
nematode diseases
Diversity
Infects over 1 million species of insects and other invertebrates!
Google imagesGoogle images
Google images Google images Google images
Stevens et al, 2001
Wolbachia in insects
• Maternally inherited (Usually)
• Cytoplasmic incompatibility
• Induced parthogenesis, functional feminization, and male killing
• Protection from parasitoid wasp in pea aphids
• Evolutionary implications
Cytoplasmic Incompatibility (CI)
Cytoplasmic incompatibility
Tortora et al, 2010
Biocontrol (economic implications)
• Cytoplasmic incompatibility has enormous implications for bio-control
• Exp 1) The Med fly- experimentally inoculated males induced complete (CI) in target populations
• Populations were “suppressed” by a single release of infected males
Zabalou et al, 2004
Evolutionary Implications
Experiment 2- Antibiotic treatment in wasps
• Does Walbachia help maintain the uniqueness of it’s hosts species by impeding “hybrid” development?
• How has Wolbachia influenced the evolution of insects?
Google images
Hybridization!
A twist: Wolbachia is found in filarial nematodes where it is discovered to be
an vital symbiont
Google images
Co-evolution• Strong evidence for co-evolution between
endosymbiont Wolbachia and nematodes
• Phylogenetic congruency
• Long history of vertical transmission
An Obligate Endosymbiosis• Wolbachia vital for embryogenesis in adult females
• Inhibition of microfilariae
• Molt inhibition
Filariasis in Humans and animals
• 200 million individuals infected across 90 countries (krager, 2007 as cited by Hoerauf)
Canine Heart WormD. immitis
Elephantiasis /ESLFWuchereria bancrofti
River BlindessO. ochengi
Traditional Treatment (Filariasis)Traditional treatment for lymphatic
Filariasis - Ivermectin
Now- Effectively use chemotherapy to disrupt parasite/symbiont interactions in filarial nematodes
Medical Application?Experiment 3
• A doxycyline regime can be used to treat (Ghanaian) individuals for lymphatic filariasis by targeting the host symbiont
• Results: a 99% reduction in microfilaria
• Implications- doxycyline as a universal treatment for filariasis in humans
Ivermectin vs Doxycycline
$111.17 USD/ 3 mg (Merck)
Neurotoxic effects
Annual Treatment-Kills the microfilariae not the worm
$225.99 USD/100mg
Pregnancy risk factor D
6 weeks course, makes adult worms sterile
VSGoogle images
Google images
Conclusions• Wolbachia is a fundamental bacteria genus
• Further study of this endosymbiont will enhance our understanding of evolutionary entomology, Nematode symbiont coeveolution, and other biological systems
• Targeting Wolbachia for biocontrol and disease eradication will have huge economic and medical benifits
References
Stevens, L., Giordano, R., & Fialho, R. F. (2001). MALE-KILLING, NEMATODE INFECTIONS, BACTERIOPHAGE INFECTION, AND VIRULENCE OF CYTOPLASMIC BACTERIA IN THE GENUS WOLBACHIA. Annual Review of Ecology & Systematics, 32: 519
Hoerauf, A., Mand, S., Fischer, K., Kruppa, T., Marfo-Debrekyei, Y., Debrah, A., & ... Bättner, D. W. (2003). Doxycycline as a novel strategy against bancroftian filariasis—depletion of Wolbachia endosymbionts from Wuchereria bancrofti and stop of microfilaria production. Medical Microbiology & Immunology... Study 3
Sofia Zabalou, Markus Riegler, Marianna Theodorakopoulou, Christian Stauffer, Charalambos Savakis, Kostas Bourtzis, John H. Law (2004). Wolbachia-Induced Cytoplasmic Incompatibility as a Means for Insect Pest Population Control. Proceedings of the National Academy of Sciences of the United States of America Vol. 101, No. 42 (Oct. 19, 2004), pp. 15042-15045....Study 1
Tortora, G., Funke, B., Case, C. (2010).Microbiology: An Introduction 10th Ed. 305-307...Study 2
Hoerauf, A., Rao, R. U. (2007). Wolbachia: A Bug’s Life in another Bug
Questions