MAR 08, 2017 7:45 AM PST

Fruit Flies Lay Fewer Eggs in Response to Bacterial Infection

WRITTEN BY: Kara Marker

Before their eggs even hatch, fruit flies are protective over their offspring. After discovering a another protective behavior of fruit flies that helps them avoid dangerous bacteria harbored by contaminated food, researchers from Aix-Marseille decided to look for similar protective mechanisms.

Fruit flies, a species of fly called Drosophila melanogaster, live for only 30 days.

They found that, in response to bacterial infection, fruit flies pause their egg-laying via nerve cell signaling pathways along with an anti-microbial immune response reminiscent of the human immune response to pathogens. This deliberate and temporary interruption in egg-laying ultimately protects their future offspring from infection.

Leader of the study, professor Julien Royet from Aix-Marseille University in France, and his team investigated the signal that was communicating to the fruit flies to halt reproduction. "We know that peptidoglycan, a component of the bacterial cell wall, activates the NF-kB pathway, which controls the immune response in the fruit fly,” he said. “We were however surprised to see that injection of purified peptidoglycan into the flies also affects egg-laying, suggesting that the same bacterial component regulates both immune and behavioural responses to bacteria."

The NF-kB pathway is a pro-inflammatory signaling pathway that expresses genes coding for cytokines, chemokines, and adhesion molecules. These are chemical messengers produced by the immune system to communicate different messages throughout the body, making the NF-kB pathway a common target for anti-inflammatory drugs.

"Since egg-laying behaviour is controlled by a complicated neuronal network in flies, one possibility was that peptidoglycan is acting directly on this network," explained lead author C. Leopold Kurz. "We tested this hypothesis using various mutants and saw that, unexpectedly, peptidoglycan is indeed sensed by neurons."

Neurons producing a key neurotransmitter involved in ovulation, called octopamine, are the ones that sense peptidoglycan and temporarily inhibit the laying of eggs. Researchers confirmed this finding when they observed a threefold increase in matured eggs waiting in the ovaries in flies with infections compared to uninfected flies. 24 hours later, egg-laying continued like normal.

With this finding determined, scientists next will wonder: does a similar protective mechanism occur in more complex organisms, even ones that do not lay eggs?

“Our findings show that bacterial infection regulates ovulation by affecting the octopaminergic signalling pathway in neurons, via activation of the NF-kB pathway," Royet summarized. "A future challenge will be to test whether this NF-kB-dependent response to peptidoglycan following infection also occurs in the neurons of higher organisms and directly influences animal behaviour."

Royet’s study was published in the journal eLife.

Sources: Cold Spring Harbor Perspectives in Biology, Aix-Marseille University

About the Author
  • I am a scientific journalist and enthusiast, especially in the realm of biomedicine. I am passionate about conveying the truth in scientific phenomena and subsequently improving health and public awareness. Sometimes scientific research needs a translator to effectively communicate the scientific jargon present in significant findings. I plan to be that translating communicator, and I hope to decrease the spread of misrepresented scientific phenomena! Check out my science blog: ScienceKara.com.
You May Also Like
JAN 27, 2020
Health & Medicine
JAN 27, 2020
Low Number of Vaccine Injury Claims Demonstrate Their Safety
To spread awareness of vaccine safety, New York Times reporters Pam Belluck and Reed Abelson wrote a comprehensive report about vaccine injury claim data....
JAN 27, 2020
Cancer
JAN 27, 2020
How cancer tricks our immune systems
Research published yesterday in Nature details the finding of a new “Don’t eat me” signal that cancers use to hide from the body’s ...
JAN 27, 2020
Immunology
JAN 27, 2020
New Research In Reversing Deafness
Hair cells inside the human ear are responsible for sensing and relaying sound to the brain.  In all mammals except humans, these cells can regenerate...
JAN 27, 2020
Immunology
JAN 27, 2020
New Observations of a Cancer Transcriptase
New research shows a transcriptase that helps time cell death varies in expression, and is unusually localized, in cancer cells.  The transcriptase, T...
JAN 27, 2020
Drug Discovery & Development
JAN 27, 2020
Effective Vaccines for Lyme Disease?
Currently, there are no effective vaccines available for the presentation of Lyme disease. The only preventive efforts present includes “guiding&rdqu...
JAN 27, 2020
Cell & Molecular Biology
JAN 27, 2020
In a First, Scientists Generate Early Human Immune Cells in the Lab
Now we know more about the early stages of the human immune system....
Loading Comments...