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Related Concept Videos

Circadian Rhythms and Gene Regulation02:19

Circadian Rhythms and Gene Regulation

The biological clock is involved in many aspects of regulating complex physiology in all animals. It was in 1935 when German zoologists, Hans Kalmus and Erwin Bünning, discovered the existence of circadian rhythm in Drosophila melanogaster. However, the internal molecular mechanisms behind the circadian clock remained a mystery until 1984, when Jeffrey C. Hall, Michael Rosbash, and Michael W. Young discovered the expression of the Per gene oscillating over a 24-hour cycle. In subsequent years,...
Circadian Rhythms and Gene Regulation02:19

Circadian Rhythms and Gene Regulation

The biological clock is involved in many aspects of regulating complex physiology in all animals. It was in 1935 when German zoologists, Hans Kalmus and Erwin Bünning, discovered the existence of circadian rhythm in Drosophila melanogaster. However, the internal molecular mechanisms behind the circadian clock remained a mystery until 1984, when Jeffrey C. Hall, Michael Rosbash, and Michael W. Young discovered the expression of the Per gene oscillating over a 24-hour cycle. In subsequent years,...
Biological Clocks and Seasonal Responses02:45

Biological Clocks and Seasonal Responses

The circadian—or biological—clock is an intrinsic, timekeeping, molecular mechanism that allows plants to coordinate physiological activities over 24-hour cycles called circadian rhythms. Photoperiodism is a collective term for the biological responses of plants to variations in the relative lengths of dark and light periods. The period of light-exposure is called the photoperiod.
Background and Environment Affect Phenotype02:27

Background and Environment Affect Phenotype

Although the genetic makeup of an organism plays a major role in determining the phenotype, there are also several environmental factors, such as temperature, oxygen availability, presence of mutagens, that can alter an organism’s phenotype.
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...

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In Vitro Bioluminescence Assay to Characterize Circadian Rhythm in Mammary Epithelial Cells
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Metabolic circadian rhythms in embryonic turtles.

Fiona Kay Loudon1, Ricky-John Spencer, Alana Strassmeyer

  • 1Water and Wildlife Ecology Group, Native and Pest Animal Unit, School of Science and Health, University of Western Sydney, Locked Bag 1797, Penrith South DC, New South Wales 1797, Australia. f.loudon@uws.edu.au

Integrative and Comparative Biology
|May 9, 2013
PubMed
Summary

Embryonic turtle heart rates show circadian rhythms by mid-gestation, establishing earlier than in other vertebrates. These rhythms may coordinate synchronous hatching and nest emergence.

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Area of Science:

  • Developmental biology
  • Chronobiology
  • Herpetology

Background:

  • Oviparous species offer insights into embryonic circadian rhythms, free from maternal influence.
  • Embryonic turtle heart rates vary, potentially responding to developmental stage and nest environment.

Purpose of the Study:

  • To establish baseline embryonic heart rate profiles in Emydura macquarii turtles.
  • To determine when metabolic circadian rhythms emerge during turtle embryogenesis.

Main Methods:

  • Turtle eggs were incubated at constant temperatures (26°C and 30°C).
  • Embryonic heart rates were monitored every 6 hours over 24-hour periods every 7-11 days until hatching.

Main Results:

  • Circadian heart rate rhythms were detected by mid-gestation and persisted until hatching.
  • Daily heart rate fluctuations reached up to 20%, independent of the time of day.

Conclusions:

  • Endogenous circadian rhythms in turtle embryos establish earlier than in other vertebrates.
  • Early establishment of heart rate circadian rhythms may facilitate embryonic communication and synchronized hatching.