Off-campus SJSU users: To download campus access theses, please use the following link to log into our proxy server with your SJSU library user name and PIN.

Publication Date

Summer 2022

Degree Type

Thesis - Campus Access Only

Degree Name

Master of Science (MS)




Alberto A. Rascón

Subject Areas



The female Aedes aegypti mosquito is one of the most effective vectors of viruses that lead to disease such as zika, dengue, chikungunya, and yellow fever viruses. These viruses are effectively transmitted during the uptake of a blood meal. The blood meal contains proteins which are degraded by midgut proteases to the necessary nutrients for the development and production of eggs. Although recent studies suggest that JHA15 may be involved in the blood meal digestion process, direct evidence is lacking; therefore, the protease was isolated and studied in vitro. In vitro studies include the recombinant expression of the Ae. aegypti mosquito JHA15 gene in SHuffle® T7 express competent E. coli cells. Initial expression and purification of different JHA15 constructs showed auto-catalytic activity. This project focused on mutating the pro-peptide region of different JHA15 constructs to prevent auto-activation and to determine if the protease constructs do indeed auto-activate at this region. JHA15 mutants were recombinantly and solubly expressed in SHuffle® T7 express competent E. coli cells, and purified; this yielded no auto-activation activity as cleavage of the substrate Bz-Phe-Val-Arg-pNA was absent during activity assays. Studying the overall in vitro activity of the protease will help with midgut protease inhibitor development. Blood meal protein digestion is necessary for egg production in the mosquito but studying JHA15 and other midgut proteases could help in reducing the number of mosquito eggs produced and minimize pathogen transmission. Specificity of the inhibitor will ensure that ecologically beneficial pollinators are not affected.

Available for download on Tuesday, November 02, 2027