Chemist targets pesky mosquitoes' genes
Female mosquitoes undergo more genetic changes than males

Date:
February 22, 2022
Source:
University of Cincinnati
Summary:
The next generation of mosquito control might target the pests'
reproductive genes. Researchers examined genetic material of three
species of mosquito responsible for killing millions of people
around the world each year. Researchers revealed the surprising
genetic modifications female mosquitoes undergo, in part to create
the next generation.



FULL STORY ==========================================================================
The next generation of mosquito control might target the pests'
reproductive genes.


========================================================================== Researchers at the University of Cincinnati examined genetic material
of three species of mosquito responsible for killing millions of people
around the world each year. In a collaboration between UC's chemistry
and biology departments, researchers revealed the surprising genetic modifications female mosquitoes undergo, in part to create the next
generation.

Using tools called liquid chromatography-tandem mass spectrometry,
researchers found as many as 33 genetic modifications in the transfer
RNA of female mosquitoes. Like DNA, transfer RNA serves as the building
blocks of life, communicating the genetic code from DNA to build new
proteins that regulate the body's tissues and organs.

"That's important because it means there are different requirements for
making proteins in males and females," said Melissa Kelley, lead author
and a postdoctoral researcher in UC's College of Arts and Sciences.

"Proteins do a bunch of things: they do the housekeeping needed to keep
an organism alive. And there are specialized ones that are created like
when females are getting ready to lay eggs," Kelley said.

By better understanding these modifications at the molecular level,
scientists might be able to find a new weapon to control mosquito
populations.



==========================================================================
UC is not alone. Researchers around the world are looking at ways to
target the genes of mosquitoes to prevent mosquito-borne disease.

Mosquitoes cause more human misery than virtually any other pest. More
than 229 million people were diagnosed with malaria in 2019. Mosquitoes
also carry yellow fever, Dengue fever and West Nile virus, among others.

"There is a constant need for new methods of control," Kelley said.

Mosquitoes were responsible for reshaping entire landscapes in the United States. Mosquito-control commissions funded with federal dollars launched massive projects to drain and fill wetlands in the 1930s. Pesticides
soon replaced labor-intensive water management policies. The popular insect-killer DDT was banned in 1972 after research discovered the
toxin was accumulating in the food chain and affecting wildlife such as
bald eagles.

Various tools are used to fight mosquitoes, from dispersing fish that
feast on mosquito larvae to releasing hordes of sterile males into the
wild. But pesticides remain a popular solution.



==========================================================================
"And there have been reports of increased pesticide resistance in
mosquitoes," Kelley said.

UC chemist Patrick Limbach, UC's vice president for research, was a
co-author of the paper.

"As carriers of multiple human diseases, understanding the mechanisms
behind mosquito reproduction may have implications for remediation
strategies," Limbach said.

Students cultivate six species of mosquito in biologist and associate
professor Joshua Benoit's lab.

UC studied three of them for the genetic study: Aedes aegypti, Culex
pipiens and Anopheles stephensi. The first, found in Africa, the
Mediterranean and the southeastern United States, is a known vector
for yellow fever, dengue, Zika virus and chikungunya. Culex pipiens
is a mosquito found around the world and has been linked to West Nile
virus. The last is an Asian mosquito that has been linked to malaria
outbreaks. All three species require a blood meal for reproduction.

Female and male mosquitoes have obvious physical differences. Typically
smaller with fuzzy antennae, male mosquitoes don't suck blood like
females that need nutrients to make the next generation.

"We were curious if there were differences in how they make proteins,"
Kelley said.

UC researchers found that female mosquitoes have a higher abundance of
tRNA modifications than males. Female mosquitoes likely utilize chemical modifications to tRNA more abundantly than males, which could underlie
factors associated with female reproduction.

UC undergraduate biology student Melissa Uhran said she was fortunate
to take part in the study.

"It was a great opportunity. I'm grateful to get a chance to do
it. It's given me a lot of experience that will help me career-wise,"
she said. "And I've learned a lot." UC's project was supported by grants
from the National Institute of Allergy and Infectious Diseases of the
National Institutes of Health.

========================================================================== Story Source: Materials provided by University_of_Cincinnati. Original
written by Michael Miller. Note: Content may be edited for style and
length.


========================================================================== Journal Reference:
1. Melissa Kelley, Melissa Uhran, Cassandra Herbert, George Yoshida,
Emmarie
R. Watts, Patrick A. Limbach, Joshua B. Benoit. Abundances
of transfer RNA modifications and transcriptional levels of
tRNA-modifying enzymes are sex-associated in mosquitoes. Insect
Biochemistry and Molecular Biology, 2022; 143: 103741 DOI:
10.1016/j.ibmb.2022.103741 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/02/220222135133.htm

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