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Examples include circannual or annual cycles that govern migration or reproduction cycles in many plants and animals, or the human menstrual cycle. Ultradian rhythms , which are cycles shorter than 24 hours, such as the 90-minute REM cycle , the 4-hour nasal cycle , or the 3-hour cycle of growth hormone production.
CCA1 – The CCA1 gene, also known as Circadian and Clock Associated Gene 1, is a gene that is especially important in maintaining the rhythmicity of plant cellular oscillations. Overexpression, results in the loss of rhythmic expression of clock controlled genes (CCGs), loss of photoperiod control, and loss of rhythmicity in LHY expression.
Overview, including some physiological parameters, of the human circadian rhythm ("biological clock").. Chronobiology is a field of biology that examines timing processes, including periodic (cyclic) phenomena in living organisms, such as their adaptation to solar- and lunar-related rhythms. [1]
A better understanding of plant circadian rhythms has applications in agriculture, such as helping farmers stagger crop harvests to extend crop availability and securing against massive losses due to weather. Light is the signal by which plants synchronize their internal clocks to their environment and is sensed by a wide variety of photoreceptors.
The circadian clock in plants has completely different components to those in the animal, fungus, or bacterial clocks. The plant clock does have a conceptual similarity to the animal clock in that it consists of a series of interlocking transcriptional feedback loops. The genes involved in the clock show their peak expression at a fixed time of ...
Post-translational feedback loops (PTFLs) involved in clock gene regulation have also been uncovered, often working in tandem with the TTFL model. In both mammals and plants, post-translational modifications such as phosphorylation and acetylation regulate the abundance and/or activity of clock genes and proteins.
It has been argued that for plants that display foliar nyctinasty, it is a crucial mechanism for survival; however, most plants do not exhibit any nyctinastic movements. [1] Nyctinasty is found in a range of plant species and across xeric , mesic , and aquatic environments, suggesting that this singular behavior may serve a variety of ...
Bacterial circadian rhythms, like other circadian rhythms, are endogenous "biological clocks" that have the following three characteristics: (a) in constant conditions (i.e. constant temperature and either constant light {LL} or constant darkness {DD}) they oscillate with a period that is close to, but not exactly, 24 hours in duration, (b) this "free-running" rhythm is temperature compensated ...