Chinwendu Amazu, Biochemistry and Molecular Biology
"Towards Paratrangenisis: Selection of Bacteria that are Vertically Transmitted by Mosquito Vectors"
The paratransgenic approach that is using engineered symbiotic bacteria as vehicle to deliver anti-malaria “effector molecules” to interfere with parasite development in the mosquito midgut has been considered as a promising strategy to fight malaria disease. A bacterium that is well adapted to the mosquito midgut and can efficiently be transmitted to the next generation is a strong foundation in introducing recombinant bacteria into field mosquito populations. Recently, a bacterium Asaia sp. strain SF2.1 was reported to be well colonized in female Anopheles stephensi, and possibly able to be transmitted vertically from female mosquito to larval progeny. However, preliminary experiments suggested that Asaia sp. SF2.1 survival from mother to offspring or from larval to adult were poor. To select for bacteria that are well adapted to the An. gambiae, a major vector of human malaria in Africa, we performed experiments to test the survivability, recolonization, vertical and/or transstadial transmissions of Asaia sp. SF2.1 in An. gambiae. In addition, we also selected for other local symbiotic bacteria that were transmitted vertically or transstadially in the An. gambiae. The hypothesis stated that Asaia sp. SF2.1 can colonize and survive in the midgut, and can be transmitted transstadially, from midgut to ovary and vertically in An. gambiae. To identify if Asaia sp. SF2.1 was present in the mosquito or in the mosquito’s midgut/ovary; we used RFP-targeted Asaia sp. SF2.1 (Ab-RFP) and fed it to An. gambiae at different periods of their life span. After different time intervals, we dissected and homogenized either the whole mosquito, midgut or ovary, plated and incubated for two days. We have demonstrated that Ab-RFP stably maintained in the midgut for the adult life span of An. gambiae. All the dissected female adults harbored fluorescent Asaia Ab-RFP in 24 h after the mosquito was fed Ab-RFP. To select for Asaia and other bacteria that vertically transmitted from mother to offspring, we isolated bacteria that colonized in ovary and larval progeny. We found Asaia sp. and Serratia sp. were able to traverse the midgut to colonize in the ovaries, suggesting that they could be transmitted vertically from mother to offspring. Although, a large amount of reintroduced Asaia Ab-RFP outcompeted local Asaia, Serratia sp. became the most dominant bacterium in the ovary four days after the mosquito fed on bloodmeal. These findings show that both Serratia sp. and Asaia sp. are excellent candidates for paratransgenic control of malaria.
Where are you doing research this summer?
I am at the Johns Hopkins University Bloomberg School of Public Health in the Johns Hopkins Malaria Research Institute.
What is your project?
I am working on Malaria, seeing if we can use bacteria already stabilized in the mosquito to secrete effector cells that will stop parasite transmission within the mosquito. I am working specifically with Asaia bogorensis, a bacteria, to see if it can become well-adapted and be passed on to future progeny in the mosquito vector, Anopheles gambiae.
How did you find out about research opportunities for Summer 2011?
I found out through searching universities and institutes that dealt with research summer programs. Also, Meyerhoff Scholars Program, which I am in, helped me search for summer research opportunities.
When did you start looking for a position? How many places did you apply?
I started looking for a position in October of last year. I applied to 17 institutions.
Was this your first research experience? What background did you have before starting this summer research?
This was my first summer research experience, but in my senior year of high school, I worked and interned at United States Department of Agriculture.
Are there other undergraduates involved in the same research this summer? Who do you work with directly each day?
Yes there are other undergraduates in this summer program. I work directly with one of the post-doctoral fellows in my lab.
What did you gain from this experience?
I learned that research is an ocean, filled with different parts and things that you can focus on. It is vast but it is also a place where you don't look at the time often and time goes by very quickly. I gained a great deal of lab experience that I will take on with me to my future lab positions. I now have more networking opportunities and I am a better presentation speaker. This experience has also supported my educational and career goals in a positive way.
Where are you living while you do this summer research?
I am living at UMBC.
What is your advice to other UMBC students about summer research?
Summer research is an awesome opportunity that can open up doors for you, sharpen your mind and technical skills, and can also allow you to delve into topics that are truly important in this world and in our future.
Can you tell us your major and your plans for the future?
I am a Biochemistry and Molecular Biology major. I am graduating from UMBC in 2014, and I plan to attain my MD/PhD at an accredited institution.