MAR 08, 2017 07:45 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
NOV 19, 2018
Cell & Molecular Biology
NOV 19, 2018
How Mitochondria can Help the Cell Fight Pathogens
Some pathogens can get around out bodies' natural defense mechanisms. So our body developed a Plan B....
MAR 11, 2019
Drug Discovery
MAR 11, 2019
PARP Inhibitors Boost Immune Efficacy
In a recent research study, precision cancer drugs called PARP inhibitors are previously known to boost the immune system were found to spark a powerful im...
APR 02, 2019
Cancer
APR 02, 2019
Widely Prescribed Breast Cancer Medication Promotes Metastasis
The primary goals of metastatic breast cancer treatment are to ensure that the patient has the longest survival possible while experiencing the highes...
MAR 31, 2019
Drug Discovery
MAR 31, 2019
Glowing Tumors Reveal How Immunotherapeutics Work
In a study published in the Journal of Clinical Investigation, researchers used positron emission tomography (PET) scans to examine how an immunotherapy dr...
APR 09, 2019
Health & Medicine
APR 09, 2019
Toxic Air is Shortening Children's Lifespans
According to the State of Global Air 2019 report, air pollution is currently shortening life expectancy by an average of 20 months worldwide. This means th...
APR 15, 2019
Immunology
APR 15, 2019
Fecal Transplant improves ASD
Our understanding of the brain-gut connection is increasing by the day. Individuals with autism spectrum disorder (ASD) also experience gastrointestinal sy...
Loading Comments...