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NMSU honors biology professor’s mosquito research at Scholarly Excellence Rally

New Mexico State University Associate Professor Jiannong Xu has received a $1.2 million SCORE grant from the National Institute of Allergy and Infectious Diseases, one of the National Institutes of Health, to study “Bacterial Colonization and Immunogenicity in Mosquito Gut Ecosystem.”



NMSU biology professor Jiannong Xu speaks during a research rally event at O'Donnell Hall. (NMSU Photo)

“Dr. Xu’s lab is a testimony of the integration between research and teaching,” said Greg Fant, associate vice president and deputy provost, at an NMSU Scholarly Excellence Rally honoring Xu.

Xu was recently promoted to associate professor in the College of Arts and Sciences’ biology department. He is studying how bacteria inhabit the gut and how they affect mosquito immunity. Mosquitoes can transmit infectious diseases such as malaria, Dengue fever and West Nile virus.

Malaria is a worldwide problem affecting millions of people each year. Despite the effectiveness of insecticides, their usefulness is threatened by mosquitoes building resistance against the chemicals.

Xu and a group of graduate students are looking at ways of manipulating the bacteria that reside inside the gut of the malaria mosquito, Anopheles gambiae. The current project is to characterize the roles of bacterial cell wall structure, lipopolysaccharide (LPS), in the gut colonization and in priming mosquito basal immunity.

Their main objective is to inhibit the malaria parasite and prevent the mosquito’s ability to reproduce, thereby resulting in mosquitoes laying fewer eggs and reducing the population.

“We are working on mosquito associated microbes,” Xu said. “The mosquito gut is a small ecosystem where many bacteria reside. These bacteria are important for mosquito life. Without these symbiotic bacteria, mosquitoes would not be happy in terms of fecundity/fertility and immune defense. We have characterized the bacterial composition and their genetic capacity in the mosquito gut.

“The essential nutrients that the bacteria provide for the mosquito host is very important for the mosquito lifecycle,” he explained. “If we can change that bacterial community inside the mosquito gut, then we might make the mosquito produce fewer eggs and the whole population will be smaller and it would help us to reduce malaria transmission.”

Xu and his student researchers can already tell which bacteria are associated with each stage of a mosquito’s life.

Xu’s students include Dong Pei and Jinjin Jiang. His first Ph.D. student, Phanidhar Kukutla, is about to graduate and has already been offered a postdoc at Cornell University. Lab technician Ivy Yu also assists on the project. Collaborators include NMSU professors Michele Nishiguchi, biology, and Joe Song, computer science, as well as Xiaoqiang Yu of the University of Missouri Kansas City.

“We have generated a mutant library for a strain of bacteria from mosquito gut and obtained several mutant strains in which the bacterial cell wall structure LPS is defective,” Xu said. “With the understanding of the microbial structure and functionality, we would be able to exploit the knowledge to develop tools to manipulate the microbes to reduce fertility and vector competence, a synthetic biology approach for mosquito control and intervention of mosquito-borne diseases.”

A previous three-year grant from NIH SCORE allowed Xu’s group to study how bacteria remain in the mosquito gut and form a stable community. They’ve also compared lab mosquitoes to wild mosquitoes in Kenya, through collaboration with researchers at the University of California Irvine. They found that the mosquito gut is selective and only core bacteria survive in the gut.

Xu is currently on sabbatical from NMSU.