Uncovering the Secrets of Animal Feeding Cycles: Insights from Fruit Flies and their Genes

summary: Researchers use fruit flies to uncover the secrets of animals’ daily diets. They found that the quasimodo gene (qsm) synchronizes feeding patterns with light and dark, while the clock-like (clk) and cycle (cyc) genes regulate feeding and fasting cycles. Interestingly, it is neurons, not metabolic networks, that ensure these cycles are consistent with circadian 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 synchronize feeding patterns with light and dark cycles. In constant darkness, the genetic clock (clk) and cycle (cyc) determine the feeding/fasting rhythm. Molecular clock genes in neurons, not in metabolic networks, synchronize these rhythms with circadian cycles.

source: Tokyo Metropolitan University

Researchers from Tokyo Metropolitan University used fruit flies to study how they regulate their daily diet.

They found that the quasimodo gene (qsm) helps synchronize feeding with the light/dark cycle, but not in constant darkness: instead, the clock gene (clk) and the (cyc) maintains the feeding/fasting cycle, while other “clocks” in neurons help synchronize it with the day. Deciphering the molecular mechanisms behind feeding cycles helps us understand animal behavior, including our own.

They used a method known as the CAFE test, in which flies are fed through tiny capillaries to measure how much the flies eat at different times. Credit: Neuroscience News

Many members of the animal world eat at about the same time every day. This arises from the need to adapt to aspects of the environment, including the amount of light available, temperature, food availability, and the possible presence of predators, all of which are important for survival. It is also important for efficient digestion and metabolism, and therefore for our overall well-being.

But how do various organisms know when to eat? One important factor is the circadian rhythm, a physiological cycle that various organisms such as animals, plants, bacteria and algae have almost every day. It functions as a “master clock” that regulates rhythmic behavior.

But animals also have other timing mechanisms, known as “peripheral clocks,” each of which has different biochemical pathways. This can be reset by external factors, such as nutrition. But how this clock regulates animal feeding behavior remains unclear.

Now a team led by Associate Professor Kanae Ando from Tokyo Metropolitan University has tackled this problem using fruit flies, a model organism that mirrors many of the traits of more complex animals, including humans. They used a method known as the CAFE test, in which flies are fed through tiny capillaries to measure how much the flies eat at different times.

First, they observed how the flies synchronized their feeding habits with light. By studying flies that feed in light/dark cycles, previous research has shown that flies eat more during the day even when mutations occur in the core periodic (per) and perpetual (tim) circadian clock genes. Instead, the team looked at quasimodo (qsm), a gene that codes for a light-responsive protein that controls the activation of clock neurons.

By turning off the Qsm system, they found that the flies’ daytime feeding patterns were significantly affected. For the first time, we know that synchronization of feeding with light rhythms is influenced by QSM.

This does not happen to flies that forage in complete darkness. Flies with mutations in essential circadian genes experience severe disruption of their circadian feeding patterns.

Of the four genes involved, period (per), lasting (tim), cycle (cyc) and clock (clk), the loss of cyc and clk was much more severe. Indeed, it was found that clk/cyc is very important in establishing a bimodal eating pattern, namely periods of eating and fasting, especially in metabolic networks.

But how does this cycle coincide with the day? Instead of metabolic networks, molecular clock genes in neurons play a dominant role.

The team’s findings give us a glimpse into how different clocks in different parts of an organism regulate feeding/fasting cycles, as well as how they relate to diurnal rhythms.

Understanding the mechanisms behind eating habits promises new insights into animal behavior, as well as new treatments for eating disorders.

Financing: This work was supported by the Farber Neuroscience Institute, Thomas Jefferson University, and the National Institutes of Health [R01AG032279-A1]and Takeda Foundation grants, and the TMU Strategic Research Fund.

About genetic research news

author: Ayo Totsukawa
source: Tokyo Metropolitan University
communication: Go to Totsukawa – Tokyo Metropolitan University
picture: Image credited to Neuroscience News

Original search: Open access.
“Anatomy of circadian eating patterns: Peripheral clocks/cycles generate feeding/fasting cycles and neuromolecular clocks synchronize them“By Kanae Ando et al. iSains

summary

Anatomy of circadian eating patterns: Peripheral clocks/cycles generate feeding/fasting cycles and neuromolecular clocks synchronize them

A 24-hour rhythm of feeding behavior, or synchronized feeding/fasting episodes during the day, is critical for survival. Internal clocks and light input regulate circadian behavior, but how feeding rhythms are generated is not fully understood. Here we aim to dissect the molecular pathways that generate daily eating patterns.

By measuring the amount of food each fly eats almost daily, we show that the establishment of a feeding rhythm under light:dark conditions requires com.quasimodo (qsm) but not a molecular clock.

Under constant darkness, the circadian feeding pattern consists of two components: a clock (CLK) in digestive/metabolic networks that generates feeding/fasting loops, and a molecular clock in neurons that synchronizes it with subjective daylight.

Although CLK is part of the molecular clock, the establishment of the feeding/fasting loop by CLK in the metabolic network is independent of the molecular clock mechanism.

Our results reveal a new function for qsm and CLK in eating rhythm Fruit fly.

2023-10-28 21:56:36
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