Effects of Jack Bean urease on Insect Blood
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Date
2012-12
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Publisher
The Ohio State University
Abstract
Jackbean (Canavalia ensiformis) ureases are entomotoxic to hemipteran insects, an effect partially due to the release of internal peptides by insect's cathepsin- like digestive enzymes. Here we studied the effects of the major jackbean urease isoform (JBU) on isolated hemocytes of 5th instars Dysdercus peruvianus’. JBU (200 nM) was found to trigger in vitro microaggregation of hemocytes, visualized under light microscopy and also after DAPI stain. Hemocytes were suspended in a calcium free saline before exposure to JBU, and the absence of external calcium did not change the aggregating effect of JBU. In the presence of JBU, there were a smaller number of melanized cells in the calcium-free saline than in regular saline. The eicosanoid synthesis indirect inhibitor dexamethasone was used for testing a possible eicosanoid modulated aggregation. Dexamethasone (50 μM) was found to decrease the aggregated ion of hemocytes caused by JBU. The results suggest that JBU is activating immune reactions in D. peruvianus isolated hemocytes, probably through eicosanoid metabolites, as was seen with mammal cellular models.
Description
Research Distinction in Biology
Keywords
Insect Immune response