Transcript Cytoplasmic Incompatibility

Wolbachia
Google images
TEM; Google images
Concepts
• Endosymbioses
• Host manipulation
• Co-evolution
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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
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Google images
Infects over 1 million
species of insects and
other invertebrates!
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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
Hybridization!
• Does Walbachia help maintain the uniqueness
of it’s hosts species by impeding “hybrid”
development?
• How has Wolbachia influenced
the evolution of insects?
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A twist: Wolbachia is found in filarial
nematodes where it is discovered to be
an vital symbiont
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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 Worm
D. immitis
Elephantiasis /ESLF
Wuchereria bancrofti
River Blindess
O. 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
VS
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Google images
$111.17 USD/ 3 mg (Merck)
$225.99 USD/100mg
Neurotoxic effects
Pregnancy risk factor D
Annual Treatment
-Kills the microfilariae
not the worm
6 weeks course,
makes adult worms
sterile
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
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
Hoerauf, A., Rao, R. U. (2007). Wolbachia: A Bug’s Life in another Bug
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
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
Tortora, G., Funke, B., Case, C. (2010).Microbiology: An Introduction 10th Ed. 305307...Study 2
Questions