Summary: Researchers from Tokyo Metropolitan University used fruit flies to unravel the mystery of daily eating patterns in animals. They discovered that the quasimodo (qsm) gene aligns feeding with light and dark cycles, while genes like clock (clk) and cycle (cyc) regulate eating and fasting cycles. Interestingly, nerve cells, not metabolic tissues, ensure these cycles match daily rhythms.
These findings pave the way for deeper insights into animal behavior and potential treatments for eating disorders.
Key Facts:
- The quasimodo (qsm) gene in fruit flies helps align feeding with light and dark cycles.
- In constant darkness, the genes clock (clk) and cycle (cyc) dictate eating and fasting rhythms.
- Molecular clock genes in nerve cells, not metabolic tissues, synchronize these rhythms with day cycles.
Source: Tokyo Metropolitan University
Researchers from Tokyo Metropolitan University have used fruit flies to study how daily eating patterns are regulated.
They found that the quasimodo (qsm) gene helped sync feeding to light and dark cycles, but not in constant darkness: instead, the genes clock (clk) and cycle (cyc) keep eating and fasting cycles, while other “clocks” in nerve cells help sync it to days. Deciphering the molecular mechanism behind eating cycles helps us understand animal behavior, including our own.
Many members of the animal kingdom eat at roughly the same times each day. This is born out of the need to adapt to aspects of the environment, including light, temperature, food availability, and the presence of predators, which are all vital for survival. It is also important for efficient digestion and metabolism, thus for overall well-being.
But how do such a wide range of organisms know when to eat? An important factor is circadian rhythm, an approximately 24-hour physiological cycle shared by animals, plants, bacteria, and algae. It serves as a “master clock” that regulates rhythmic behavior.
However, animals also have other timing mechanisms known as “peripheral clocks,” each with its own unique biochemical pathways. These clocks can be influenced by external factors such as feeding. But the specific way in which these clocks govern animal feeding behavior is still not fully understood.
Now, a team led by Associate Professor Kanae Ando of Tokyo Metropolitan University has addressed this question using fruit flies as a model organism. Fruit flies share many features with more complex animals, including humans. The researchers used a method called the CAFE assay, where flies are fed through a microcapillary to measure their food intake at different times.
Firstly, they examined how flies synchronize their eating habits with light. Previous studies had shown that flies feed more during the daytime even when mutations were introduced to core circadian clock genes, period (per) and timeless (tim). The team focused on the quasimodo (qsm) gene, which encodes a light-responsive protein that controls the activity of clock neurons.
By suppressing the qsm gene, they observed significant changes in the flies’ daytime feeding pattern. This is the first evidence that the synchronization of feeding to light is influenced by the qsm gene.
However, in constant darkness, the feeding patterns of flies with mutations in their core circadian clock genes were severely disrupted. The loss of the clock (clk) and cycle (cyc) genes had a particularly significant impact on the generation of bimodal feeding patterns, which involve alternating periods of eating and fasting, especially in metabolic tissues.
Interestingly, it was found that molecular clock genes in nerve cells, rather than metabolic tissues, played a dominant role in synchronizing these feeding and fasting cycles with the day.
The team’s discoveries provide initial insights into how different clocks in different parts of an organism regulate feeding and fasting cycles and how these cycles align with daily rhythms.
Understanding the mechanisms behind feeding habits offers new perspectives on animal behavior and potential novel treatments for eating disorders.
Funding: This work was supported by the Farber Institute for Neurosciences and Thomas Jefferson University, the National Institutes of Health [R01AG032279-A1], a Takeda Foundation Grant, and the TMU Strategic Research Fund.
About this genetics research news
Author: GO TOTSUKAWA
Source: Tokyo Metropolitan University
Contact: GO TOTSUKAWA – Tokyo Metropolitan University
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Dissecting the daily feeding pattern: Peripheral CLOCK/CYCLE generate the feeding/fasting episodes and neuronal molecular clocks synchronize them” by Kanae Ando et al. iScience
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