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
JUN 06, 2020
Immunology
Cancer Cell Clusters Better At Resisting the Immune System
JUN 06, 2020
Cancer Cell Clusters Better At Resisting the Immune System
For cancerous cells in the body, it seems there is safety in numbers. Researchers from a newly published study investiga ...
JUN 29, 2020
Microbiology
Childhood Vaccine May Help Prevent Severe COVID-19 Cases
JUN 29, 2020
Childhood Vaccine May Help Prevent Severe COVID-19 Cases
Vaccines that contain live attenuated viruses may be giving people some protection from serious cases of COVID-19 that i ...
JUL 14, 2020
Coronavirus
What Makes A Strong Antibody Response to Coronavirus
JUL 14, 2020
What Makes A Strong Antibody Response to Coronavirus
Scientists all over the world are racing to develop a vaccine that effectively and safely prompts protective immunity to ...
AUG 18, 2020
Immunology
How Dolphins Could Help Us Live Longer
AUG 18, 2020
How Dolphins Could Help Us Live Longer
Dolphins are helping scientists answer the age-old question: can we stop the clock when it comes to aging? A recent stud ...
SEP 01, 2020
Immunology
Cell Atlas of Mosquito Immunology Reveals New Avenues for Eradicating Malaria
SEP 01, 2020
Cell Atlas of Mosquito Immunology Reveals New Avenues for Eradicating Malaria
Malaria is one of the biggest ongoing threats to global health — over 200 million were infected and almost half a ...
SEP 14, 2020
Microbiology
The Immune System Can Kill HIV with a Helper Molecule
SEP 14, 2020
The Immune System Can Kill HIV with a Helper Molecule
HIV attacks the human immune system's CD4 cells, a major player in the body's defense against pathogens.
Loading Comments...