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- Bidla, Gawa, et al.
(author)
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Activation of Insect Phenoloxidase after Injury : Endogenous versus Foreign Elicitors
- 2009
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In: Journal of Innate Immunity. - : S. Karger AG. - 1662-811X .- 1662-8128. ; 1:4, s. 301-308
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Journal article (peer-reviewed)abstract
- The enzyme phenoloxidase (PO) is one of the first immune molecules that was identified in invertebrates. Recently, the immune function of PO has been challenged. We tested how PO is activated following injury in 2 insects, i.e. the fruit fly Drosophila melanogaster and the wax moth Galleria mellonella. Rapid PO activation in Drosophila was limited to discrete areas of the hemolymph clot which forms after injury. Surprisingly, unlike systemic PO activation during bacterial sepsis, clot melanization was not sensitive to microbial elicitors in our assay. Instead, Drosophila clot melanization was activated by endogenous signals such as apoptotic cells and was superinduced by phosphatidylserine, a negatively charged phospholipid normally found on the inner surface of the plasma membrane and exposed during apoptosis. In contrast, melanization in G. mellonella hemolymph was stronger and more uniform and was sensitive to peptidoglycan. This shows that both exogenous and endogenous signals can trigger the same immune mechanism in species and context-dependent ways. Our findings have implications for the evolutionary dynamics of immune mechanisms and are in agreement with recent comparisons of insect immune transcriptomes.
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| 2. |
- Korayem, Ahmed, et al.
(author)
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Evidence for an immune function of lepidopteran silk proteins
- 2007
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In: Biochemical and Biophysical Research Communications - BBRC. - : Elsevier BV. - 0006-291X .- 1090-2104. ; 352:2, s. 317-322
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Journal article (peer-reviewed)abstract
- Hemolymph coagulation stops bleeding and protects against infection. Clotting factors include both proteins that are conserved during evolution as well as more divergent proteins in different species. Here we show that several silk proteins also appear in the clot of the greater wax moth Galleria mellonella. RT-PCR analysis reveals that silk proteins are expressed in immune tissues and induced upon wounding in both Galleria and Ephestia kuehniella, a second pyralid moth. Our results support the idea that silk proteins were co-opted for immunity and coagulation during evolution.
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| 3. |
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