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Maintaining Aedes aegypti Mosquitoes Infected with Wolbachia
Published on: August 14, 2017
High anti-viral protection without immune upregulation after interspecies Wolbachia transfer
Ewa Chrostek1, Marta S P Marialva1, Ryuichi Yamada2
1Instituto Gulbenkian de Ciência, Oeiras, Portugal.
Abstract:
Wolbachia, endosymbionts that reside naturally in up to 40-70% of all insect species, are some of the most prevalent intracellular bacteria. Both Wolbachia wAu, naturally associated with Drosophila simulans, and wMel, native to Drosophila melanogaster, have been previously described to protect their hosts against viral infections. wMel transferred to D. simulans was also shown to have a strong antiviral effect. Here we directly compare one of the most protective wMel variants and wAu in D. melanogaster in the same host genetic background. We conclude that wAu protects better against viral infections, it grows exponentially and significantly shortens the lifespan of D. melanogaster. However, there is no difference between wMel and wAu in the expression of selected antimicrobial peptides. Therefore, neither the difference in anti-viral effect nor the life-shortening could be attributed to the immune stimulation by exogenous Wolbachia. Overall, we prove that stable transinfection with a highly protective Wolbachia is not necessarily associated with general immune activation.
Insights
Wolbachia bacteria can protect insects from viruses. However, one strain, wAu, while protective, significantly shortens the lifespan of Drosophila melanogaster without activating general immune responses.
Area of Science:
- Microbiology
- Insect Pathology
- Symbiotic Bacteria
Background:
- Wolbachia are prevalent intracellular bacteria found in 40-70% of insect species.
- Both Wolbachia wAu (from Drosophila simulans) and wMel (from Drosophila melanogaster) confer antiviral protection to their hosts.
- Previous studies showed wMel transferred to D. simulans also has antiviral effects.
Purpose of the Study:
- To directly compare the protective and detrimental effects of Wolbachia wAu and wMel in the same host genetic background (D. melanogaster).
- To investigate whether the antiviral effects and life-shortening observed are linked to immune activation by Wolbachia.
Main Methods:
- Directly comparing wMel and wAu strains within the D. melanogaster host.
- Assessing antiviral protection conferred by each Wolbachia strain.
- Measuring the impact of Wolbachia infection on host lifespan.
- Analyzing the expression of selected antimicrobial peptides to gauge immune activation.
Main Results:
- Wolbachia wAu provided superior protection against viral infections compared to wMel in D. melanogaster.
- Wolbachia wAu exhibited exponential growth within D. melanogaster and significantly reduced host lifespan.
- No significant difference was observed in the expression of selected antimicrobial peptides between wMel and wAu infections.
- The antiviral effects and life-shortening impacts were not attributable to general immune stimulation.
Conclusions:
- Wolbachia wAu offers enhanced antiviral protection in D. melanogaster but at the cost of host lifespan.
- The potent antiviral activity and life-shortening effects of Wolbachia are not mediated by general immune activation.
- Stable transinfection with highly protective Wolbachia does not necessarily correlate with broad immune system stimulation.
