Circadian advantage

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A circadian advantage is an advantage gained when an organism's biological cycles are in tune with its surroundings. It is not a well studied phenomenon, but it is known to occur in certain types of cyanobacteria, whose endogenous cycles, or circadian rhythm, "resonates" or aligns with their environment. It is known to occur in plants also, suggesting that any organism which is able to attune its natural growth cycles with its environment will have a competitive advantage over those that do not. Circadian advantage may also refer to sporting teams gaining an advantage by acclimatizing to the time zone where a match is played.

Contents

In organisms

In the context of bacterial circadian rhythms, specifically in cyanobacteria, circadian advantage refers to the improved survival of strains of cyanobacteria whose endogenous cycles "resonate" or align with the environmental circadian rhythm. [1] For example, consider a strain with a free-running period (FRP) of 24 hours that is co-cultured with a strain that has a free-running period (FRP) of 30 hours in a light-dark cycle of 12 hours light and 12 hours dark (LD 12:12). The strain that has a 24 hour FRP will out-compete the 30 hour strain over time.

Competition studies in plants provide another example of circadian advantage. These studies have shown that an endogenous clock that resonates with environmental cycles leads to a competitive advantage in Arabidopsis thaliana. [2] Experiments with wild type, short circadian period mutants, and long circadian period mutants demonstrated that plants with a circadian period that is optimally synchronized to the environment grew fastest. The same study also showed that photosynthetic carbon fixation was directly correlated to “circadian resonance”. A different study discovered that genes involved in photosynthetic reactions of A. thaliana are under clock control. mRNAs that encode chlorophyll binding proteins and the enzyme protoporphyrin IX magnesium chelatase involved in chlorophyll synthesis were cycling. [3] The “circadian resonance” increase in productivity may arise from appropriate anticipation of sunrise and sunset, allowing for timely synthesis of light-harvesting complex proteins and chlorophyll. Therefore, the competitive advantage in A. thaliana further supports the idea that anticipation of environmental changes leads to enhanced fitness.

Rhodopseudomonas palustris is another example of the advantage in having a biological timing system that interacts with the environmental cycles. While the only prokaryotic group with a well-known circadian timekeeping mechanism is the cyanobacteria, recent discoveries involving R. palustris have suggested alternative timekeeping mechanisms among the prokaryotes. [4] R. palustris is a purple non-sulfur bacterium that has KaiB and KaiC genes and exhibit adaptive kaiC-dependent growth in 24h cyclic environments. However, R. palustris was reported to show a poorly self-sustained intrinsic rhythm, and kaiC-dependent growth enhancement was not present under constant conditions. The R. palustris system was proposed as a “proto” circadian timekeeper that exhibit some parts of circadian systems (kaiB and kaiC homologs), but not all.

Likewise, research on the endogenous circadian timekeeping mechanisms in mice further supports that “circadian resonance” is evolutionarily adaptive. One study in particular compared the fitness of wild-type mice with mutant mice which had a short free-running circadian cycle. [5] These mice had a mutation in the casein kinase 1Ɛ gene, which encodes an enzyme that is integral in controlling circadian cycle length. A mixed group of wild-type and mutant mice were then released in an outdoor experimental enclosure and, following a fourteen month timespan, the mice were monitored. The wild-type mice both survived longer and reproduced at a greater rate than the mutant mice. In fact, the mutant genotype was strongly selected against, thereby suggesting natural selection towards those genotypes that are resonant with the natural LD cycle.

It is possible that circadian clocks play a role in the gut microbiota behavior. [6] These microorganisms experience daily changes correlated with daily light/dark and temperature cycles. This occurs through behaviors such as eating rhythms on a daily routine (consumption in the day for diurnal animals and in the night for nocturnal animals). The presence of a daily timekeeper might give those bacteria a competitive advantage over others. By allowing the bacteria to sense resources coming from the host in order to prepare and metabolize them faster. There are bacteria that have daily timekeepers, and it may be possible that the microbiota have endogenous clocks which communicate with biological clocks of the host. [6] For instance, if there are some time-keeping qualities of the microorganisms within the intestines, it might be possible that they can affect the circadian system of the host. An endogenous clock may be present in some microbial species, and the presence of such an intrinsic timekeeper could be beneficial both in the gut (which experiences daily changes in nutrient availability) and the environment outside of the host (which experiences daily cycles of light and temperature). [6]

In sport

In competitive sport, a circadian advantage is a team's advantage over another by virtue of its relative degree of acclimation to a time zone versus their opponent. While this concept was explored by researchers at Stanford in 1997, [7] and at the University of Massachusetts, [8] the term was coined in 2004 by Dr. W. Christopher Winter, a sleep specialist and neurologist studying the effects of travel between time zones on Major League Baseball (MLB) performance. [9] This study was expanded into a ten-year retrospective study with a grant through MLB that was completed by Dr. Winter and his research assistant Noah H. Green, then an undergraduate student at the University of Virginia. The work was presented in 2008 at the 22nd Annual Meeting of the Associated Professional Sleep Societies in Baltimore, Maryland. [10]

Using the convention that for every time zone crossed, synchronization to that time zone requires one day, teams can be analyzed during a season to see where they are in terms of being acclimated to their time zone of play. For example, consider the Washington Nationals. If they have been competing at home for the last 3 days or more, they would be completely acclimated to Eastern Standard Time (EST). If they were to travel to Los Angeles, upon arrival they would be 3 hours off, because they traveled 3 time zones west. Every 24 hours spent on the west coast, would bring them 1 hour closer to acclimation. [11] So after 24 hours in Los Angeles, they would be 2 hours off. After 48 hours, they would be 1 hour off, and after 72 hours, they would be acclimated to west coast time and would stay that way until they left their time zone.

Unlike home field advantage which is present any time two teams play a game that is not held in a neutral site, circadian advantage does not apply to all games. In a typical MLB season, it applies to approximately 20% of games played with the other 80% featuring teams at equal circadian advantage. In sports that allow more time between games, it may apply to significantly fewer games. Circadian advantage is much more of an issue in sports that feature significant international travel.

Circadian advantage is most significant when a team holds a 3-hour advantage (or more) over another. This matchup is only encountered after very long flights where the traveling team plays soon after arrival, most commonly coast-to-coast flights in major North American and Australian leagues. As the magnitude of time zone differences between two teams becomes smaller, so too does circadian advantage.

In 2018, pilot data collected by Walter Reed Army Institute of Research, was presented at the American Academy of Sleep Medicine's annual SLEEP meeting suggested National Football League teams perform better at night versus the day as a result of circadian advantage. It also indicated that teams had fewer turnovers at night. [12]

Related Research Articles

<span class="mw-page-title-main">Circadian rhythm</span> Natural internal process that regulates the sleep-wake cycle

A circadian rhythm, or circadian cycle, is a natural oscillation that repeats roughly every 24 hours. Circadian rhythms can refer to any process that originates within an organism and responds to the environment. Circadian rhythms are regulated by a circadian clock whose primary function is to rhythmically co-ordinate biological processes so they occur at the correct time to maximise the fitness of an individual. Circadian rhythms have been widely observed in animals, plants, fungi and cyanobacteria and there is evidence that they evolved independently in each of these kingdoms of life.

<span class="mw-page-title-main">Chronobiology</span> Field of biology

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. These cycles are known as biological rhythms. Chronobiology comes from the ancient Greek χρόνος, and biology, which pertains to the study, or science, of life. The related terms chronomics and chronome have been used in some cases to describe either the molecular mechanisms involved in chronobiological phenomena or the more quantitative aspects of chronobiology, particularly where comparison of cycles between organisms is required.

Advanced Sleep Phase Disorder (ASPD), also known as the advanced sleep-phase type (ASPT) of circadian rhythm sleep disorder, is a condition that is characterized by a recurrent pattern of early evening sleepiness and very early morning awakening. This sleep phase advancement can interfere with daily social and work schedules, and results in shortened sleep duration and excessive daytime sleepiness. The timing of sleep and melatonin levels are regulated by the body's central circadian clock, which is located in the suprachiasmatic nucleus in the hypothalamus.

<span class="mw-page-title-main">Suprachiasmatic nucleus</span> Part of the brains hypothalamus

The suprachiasmatic nucleus or nuclei (SCN) is a small region of the brain in the hypothalamus, situated directly above the optic chiasm. The SCN is the principal circadian pacemaker in mammals, responsible for generating circadian rhythms. Reception of light inputs from photosensitive retinal ganglion cells allow the SCN to coordinate the subordinate cellular clocks of the body and entrain to the environment. The neuronal and hormonal activities it generates regulate many different body functions in an approximately 24-hour cycle.

A circadian clock, or circadian oscillator, is a biochemical oscillator that cycles with a stable phase and is synchronized with solar time.

<span class="mw-page-title-main">CLOCK</span> Protein-coding gene in the species Homo sapiens

CLOCK is a gene encoding a basic helix-loop-helix-PAS transcription factor that is known to affect both the persistence and period of circadian rhythms.

In the study of chronobiology, entrainment occurs when rhythmic physiological or behavioral events match their period to that of an environmental oscillation. It is ultimately the interaction between circadian rhythms and the environment. A central example is the entrainment of circadian rhythms to the daily light–dark cycle, which ultimately is determined by the Earth's rotation. Exposure to certain environmental stimuli will cue a phase shift, and abrupt change in the timing of the rhythm. Entrainment helps organisms maintain an adaptive phase relationship with the environment as well as prevent drifting of a free running rhythm. This stable phase relationship achieved is thought to be the main function of entrainment.

<span class="mw-page-title-main">Jürgen Aschoff</span>

Jürgen Walther Ludwig Aschoff was a German physician, biologist and behavioral physiologist. Together with Erwin Bünning and Colin Pittendrigh, he is considered to be a co-founder of the field of chronobiology.

Bacterial circadian rhythms, like other circadian rhythms, are endogenous "biological clocks" that have the following three characteristics: (a) in constant conditions they oscillate with a period that is close to, but not exactly, 24 hours in duration, (b) this "free-running" rhythm is temperature compensated, and (c) the rhythm will entrain to an appropriate environmental cycle.

Joseph S. Takahashi is a Japanese American neurobiologist and geneticist. Takahashi is a professor at University of Texas Southwestern Medical Center as well as an investigator at the Howard Hughes Medical Institute. Takahashi's research group discovered the genetic basis for the mammalian circadian clock in 1994 and identified the Clock gene in 1997. Takahashi was elected to the National Academy of Sciences in 2003.

<span class="mw-page-title-main">Cyanobacterial clock proteins</span> Proteins that regulate circadian rhythms

In molecular biology, the cyanobacterial clock proteins are the main circadian regulator in cyanobacteria. The cyanobacterial clock proteins comprise three proteins: KaiA, KaiB and KaiC. The kaiABC complex may act as a promoter-nonspecific transcription regulator that represses transcription, possibly by acting on the state of chromosome compaction. This complex is expressed from a KaiABC operon.

Michael Menaker, was an American chronobiology researcher, and was Commonwealth Professor of Biology at University of Virginia. His research focused on circadian rhythmicity of vertebrates, including contributing to an understanding of light input pathways on extra-retinal photoreceptors of non-mammalian vertebrates, discovering a mammalian mutation for circadian rhythmicity, and locating a circadian oscillator in the pineal gland of bird. He wrote almost 200 scientific publications.

<i>KaiC</i> Gene found in cyanobacteria

KaiC is a gene belonging to the KaiABC gene cluster that, together, regulate bacterial circadian rhythms, specifically in cyanobacteria. KaiC encodes for the KaiC protein, which interacts with the KaiA and KaiB proteins in a post-translational oscillator (PTO). The PTO is cyanobacteria master clock that is controlled by sequences of phosphorylation of KaiC protein. Regulation of KaiABC expression and KaiABC phosphorylation is essential for cyanobacteria circadian rhythmicity, and is particularly important for regulating cyanobacteria processes such as nitrogen fixation, photosynthesis, and cell division. Studies have shown similarities to Drosophila, Neurospora, and mammalian clock models in that the kaiABC regulation of the cyanobacteria slave circadian clock is also based on a transcription translation feedback loop (TTFL). KaiC protein has both auto-kinase and auto-phosphatase activity and functions as the circadian regulator in both the PTO and the TTFL. KaiC has been found to not only suppress kaiBC when overexpressed, but also suppress circadian expression of all genes in the cyanobacterial genome.

kaiA is a gene in the "kaiABC" gene cluster that plays a crucial role in the regulation of bacterial circadian rhythms, such as in the cyanobacterium Synechococcus elongatus. For these bacteria, regulation of kaiA expression is critical for circadian rhythm, which determines the twenty-four-hour biological rhythm. In addition, KaiA functions with a negative feedback loop in relation with kaiB and KaiC. The kaiA gene makes KaiA protein that enhances phosphorylation of KaiC while KaiB inhibits activity of KaiA.

<span class="mw-page-title-main">Carl H. Johnson</span> American-born biologist

Carl Hirschie Johnson is an American-born biologist who researches the chronobiology of different organisms, most notably the bacterial circadian rhythms of cyanobacteria. Johnson completed his undergraduate degree in Honors Liberal Arts at the University of Texas at Austin, and later earned his PhD in biology from Stanford University, where he began his research under the mentorship of Dr. Colin Pittendrigh. Currently, Johnson is the Stevenson Professor of Biological Sciences at Vanderbilt University.

KaiB is a gene located in the highly-conserved kaiABC gene cluster of various cyanobacterial species. Along with KaiA and KaiC, KaiB plays a central role in operation of the cyanobacterial circadian clock. Discovery of the Kai genes marked the first-ever identification of a circadian oscillator in a prokaryotic species. Moreover, characterization of the cyanobacterial clock demonstrated the existence of transcription-independent, post-translational mechanisms of rhythm generation, challenging the universality of the transcription-translation feedback loop model of circadian rhythmicity.

Susan Golden is a Professor of molecular biology known for her research in circadian rhythms. She is currently a faculty member at UC San Diego.

Andrew John McWalter Millar, FRS, FRSE is a Scottish chronobiologist, systems biologist, and molecular geneticist. Millar is a professor at The University of Edinburgh and also serves as its chair of systems biology. Millar is best known for his contributions to plant circadian biology; in the Steve Kay lab, he pioneered the use of luciferase imaging to identify circadian mutants in Arabidopsis. Additionally, Millar's group has implicated the ELF4 gene in circadian control of flowering time in Arabidopsis. Millar was elected to the Royal Society in 2012 and the Royal Society of Edinburgh in 2013.

Transcription-translation feedback loop (TTFL) is a cellular model for explaining circadian rhythms in behavior and physiology. Widely conserved across species, the TTFL is auto-regulatory, in which transcription of clock genes is regulated by their own protein products.

In chronobiology, photoentrainment refers to the process by which an organism's biological clock, or circadian rhythm, synchronizes to daily cycles of light and dark in the environment. The mechanisms of photoentrainment differ from organism to organism. Photoentrainment plays a major role in maintaining proper timing of physiological processes and coordinating behavior within the natural environment. Studying organisms’ different photoentrainment mechanisms sheds light on how organisms may adapt to anthropogenic changes to the environment.

References

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  2. ↑ Dodd AN, Salathia N, Hall A, Kévei E, Tóth R, Nagy F, Hibberd JM, Millar AJ, Webb AA (July 2005). "Plant circadian clocks increase photosynthesis, growth, survival, and competitive advantage". Science. 309 (5734): 630–3. Bibcode:2005Sci...309..630D. doi:10.1126/science.1115581. PMID   16040710. S2CID   25739247.
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  4. ↑ Ma P, Mori T, Zhao C, Thiel T, Johnson CH (March 2016). "Evolution of KaiC-Dependent Timekeepers: A Proto-circadian Timing Mechanism Confers Adaptive Fitness in the Purple Bacterium Rhodopseudomonas palustris". PLOS Genetics. 12 (3): e1005922. doi: 10.1371/journal.pgen.1005922 . PMC   4794148 . PMID   26982486.
  5. ↑ Spoelstra K, Wikelski M, Daan S, Loudon AS, Hau M (January 2016). "Natural selection against a circadian clock gene mutation in mice". Proceedings of the National Academy of Sciences of the United States of America. 113 (3): 686–91. Bibcode:2016PNAS..113..686S. doi: 10.1073/pnas.1516442113 . PMC   4725470 . PMID   26715747.
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  8. ↑ Recht LD, Lew RA, Schwartz WJ (October 1995). "Baseball teams beaten by jet lag". Nature. 377 (6550): 583. Bibcode:1995Natur.377..583R. doi: 10.1038/377583a0 . PMID   7566168. S2CID   4275658.
  9. ↑ Winter WC, Hammond WR, Vaughn BV (2005). "Tracking 'Circadian Time' as a Statistic During the 2004 Major League Baseball Season: A Pilot Study". Sleep. 28: 64–5.
  10. ↑ Winter WC, Hammond WR, Green NH, Zhang Z, Bliwise DL (September 2009). "Measuring circadian advantage in Major League Baseball: a 10-year retrospective study". International Journal of Sports Physiology and Performance. 4 (3): 394–401. doi:10.1123/ijspp.4.3.394. PMID   19953826.
  11. ↑ Arendt J, Stone B, Skene D (2000). "Jet Lag and Sleep Disruption.". In Kryger MH, Roth T, Dement WC (eds.). Principles And Practice of Sleep Medicine (3rd ed.). W.B. Saunders. p. 591.
  12. ↑ Choynowski J, Skeiky L, St Pierre M, Brager A (April 2018). "Use Of Human Performance Response Curves To Demonstrate Circadian Advantages For Teams Playing Night Games Across A National Football League Season". Sleep. 41: A68. doi: 10.1093/sleep/zsy061.171 .

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