summary: Researchers have used fruit flies to unravel the mysteries of animals’ daily eating patterns. They discovered that the quasimodo (qsm) gene regulates feeding in light and darkness, and that genes such as clock (clk) and period (cyc) regulate feeding/fasting cycles. Interestingly, nerve cells, rather than metabolic tissues, ensure that these cycles match daily rhythms.
These findings pave the way for deeper insights into animal behavior and potential treatments for eating disorders.
Important facts:
- The Drosophila quasimodo (qsm) gene helps coordinate feeding with the light-dark cycle.
- In constant darkness, genetic clocks (clk) and cycles (cyc) determine feeding/fasting rhythms.
- Molecular clock genes in nerve cells, not metabolic tissues, synchronize these rhythms with the diurnal cycle.
sauce: Tokyo Metropolitan University
Researchers at Tokyo Metropolitan University used fruit flies to study how daily eating patterns are regulated.
They found that the quasimodo (qsm) gene helps synchronize feeding to the light-dark cycle, but not in constant darkness, and that the gene controls the clock (clk) and period. (cyc) While maintaining the feeding/fasting cycle, other “clocks” within the nerve cells help synchronize it to the number of days. Decoding the molecular mechanisms behind feeding cycles can help us understand the behavior of animals, including ourselves.
Many members of the animal kingdom eat at about the same time each day. This stems from the need to adapt to aspects of the environment, such as the amount of light, temperature, food availability, and the possibility of predators being around, all of which are essential for survival. It’s also important for efficient digestion and metabolism, and therefore our overall health.
But how does such a wide range of living things know when to eat? A key factor is the circadian rhythm, a near-daily rhythm shared by organisms as diverse as animals, plants, bacteria, and algae. is the physiological cycle. It functions as a “master clock” that regulates rhythmic behavior.
However, animals are rich in other timing mechanisms known as “peripheral clocks”, each with its own distinct biochemical pathways. These can be reset by external factors such as feeding. However, it is still unclear how these clocks control feeding behavior in animals.
Now, a team led by Associate Professor Kanae Ando of Tokyo Metropolitan University has tackled this problem using the fruit fly, a model organism that reflects many of the characteristics of more complex animals, including humans. Using a method known as the CAFE assay, they fed flies through microcapillary tubes and precisely measured how much each individual fly ate at different times.
First, they investigated how flies synchronize their eating habits with light. Previous work studying flies that feed on light-dark cycles showed that even when mutations were introduced in the core circadian clock genes, periodic (per) and timeless (tim), flies continued to feed more during the day. It has already been shown that Instead, the researchers focused on quasimodo (qsm), a gene that encodes a light-responsive protein that controls the firing of clock neurons.
They found that by knocking down QSM, the flies’ diurnal feeding patterns were significantly affected. For the first time, we found that entrainment of feeding to light-mediated rhythms is influenced by QSM.
This was not the case for flies, which always feed in the dark. Flies with mutations in core circadian clock genes had severely disrupted daily feeding patterns.
Of the four genes involved, period (per), timeless (tim), cycle (cyc), and clock (clk), the loss of cyc and clk was by far the most severe. Indeed, clk/cyc was found to be required to create a bimodal feeding pattern, i.e. feeding and fasting periods, particularly in metabolic tissues.
But how are these cycles synchronized with the number of days? Instead of metabolic organization, molecular clock genes in nerve cells played a dominant role.
The researchers’ findings provide the first glimpse into how different clocks in different parts of an organism regulate feeding and fasting cycles, and how they coincide with diurnal rhythms.
Understanding the mechanisms behind eating habits holds promise for new insights into animal behavior and new treatments for eating disorders.
Funding: This research was supported by the Farber Neuroscience Institute, Thomas Jefferson University, and the National Institutes of Health. [R01AG032279-A1]Takeda Foundation Grant, and Tokyo Metropolitan University Strategic Research Fund.
About this genetics research news
author: Tsuyoshi Totsukawa
sauce: Tokyo Metropolitan University
contact: Go Totsukawa – Tokyo Metropolitan University
image: Image credited to Neuroscience News
Original research: Open access.
“Analysis of daily feeding patterns: Peripheral clocks/cycles generate feeding/fasting episodes and neuromolecular clocks synchronize them.” Written by Kanae Ando et al. iscience
abstract
Analysis of daily feeding patterns: Peripheral clocks/cycles generate feeding/fasting episodes and neuromolecular clocks synchronize them.
The 24-hour rhythm of feeding behavior, or the synchronization of feeding and fasting episodes throughout the day, is critical for survival. Biological clocks and light inputs regulate rhythmic behavior, but how they generate feeding rhythms is not fully understood. Here we aimed to dissect the molecular pathways that generate daily feeding patterns.
By measuring the semi-daily amount of food ingested by a single fly, we demonstrated that the generation of feeding rhythms under light and dark conditions requires: quasimodo (qsm) but not a molecular clock.
Under constant darkness, the rhythmic feeding pattern consists of two components. One is the gastrointestinal/metabolic tissue clock (CLK) that generates feeding/fasting episodes, and the other is the neuronal molecular clock that synchronizes during the subjective day.
Although CLK is part of the molecular clock, the generation of feeding/fasting episodes by CLK in metabolic tissues was independent of the molecular clock machinery.
Our results are qsm CLK and feeding rhythm Drosophila.
