Insights into the Evolution of Circadian Clocks Gleaned from Bacteria

Jabbur, Maria Luísa; Zhao, Chuanxi; Johnson, Carl Hirschie

doi:10.1007/978-3-030-72158-9_7

Cited by 6 publications

(6 citation statements)

References 70 publications

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“…The amplitude of the cold photoperiodic survival can be modulated by several environmental factors– namely, the daily phase of testing, light intensity, and previous exposure to cooler temperatures. In nature, as winter approaches, organisms face the shortening of daylength (and lower light intensity ( 35 ) ) that precedes a gradual lowering of average temperature by ∼1-2 months ( 36, 37 ) ). In their natural environment, cyanobacteria likely integrate multiple environmental factors to establish the timing and magnitude of their photoperiodic response.…”

Section: Discussionmentioning

confidence: 99%

Bacteria can anticipate the seasons: photoperiodism in cyanobacteria

Jabbur,

Johnson

2024

Preprint

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Photoperiodic Time Measurement is the ability of plants and animals to measure differences in day/night-length (photoperiod) and use that information to anticipate critical seasonal transformations such as annual temperature cycles. This timekeeping phenomenon triggers adaptive responses in higher organisms such as gonadal growth/regression, flowering, and hibernation. Unexpectedly, we discovered this capability in cyanobacteria, unicellular prokaryotes with generation times of only 5-6 h. Cyanobacteria in short winter-like days develop enhanced resistance to cold that involves desaturation of membrane lipids and differential programs of gene transcription, including stress response pathways. As in eukaryotes, this photoperiodic timekeeping requires an intact circadian clockwork and develops over multiple cycles. Therefore, photoperiodic timekeeping evolved in much simpler organisms than previously appreciated, and involved genetic responses to stresses that recur seasonally.

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Section: Discussionmentioning

confidence: 99%

Bacteria can anticipate the seasons: photoperiodism in cyanobacteria

Jabbur,

Johnson

2024

Preprint

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“…6 This is orchestrated by the circadian clock: Circadian regulation of behavioral and physiological functions allows an organism to predict daily changes in its environment, improving its overall fitness. 7–9 The circadian clock is synchronized to the external environment by cues termed zeitgebers, with light serving as the primary zeitgeber. 10 The eye transduces nonvisual light information directly to the suprachiasmatic nucleus (SCN).…”

Section: Clocks and Circadian Biologymentioning

confidence: 99%

Circadian Biology and the Neurovascular Unit

Li,

Tiedt,

Lawrence

et al. 2024

Circulation Research

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Mammalian physiology and cellular function are subject to significant oscillations over the course of every 24-hour day. It is likely that these daily rhythms will affect function as well as mechanisms of disease in the central nervous system. In this review, we attempt to survey and synthesize emerging studies that investigate how circadian biology may influence the neurovascular unit. We examine how circadian clocks may operate in neural, glial, and vascular compartments, review how circadian mechanisms regulate cell-cell signaling, assess interactions with aging and vascular comorbidities, and finally ask whether and how circadian effects and disruptions in rhythms may influence the risk and progression of pathophysiology in cerebrovascular disease. Overcoming identified challenges and leveraging opportunities for future research might support the development of novel circadian-based treatments for stroke.

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“…Circadian clocks allow organisms to adaptively align their rhythmic processes to predictable rhythmic changes in their environments (Jabbur et al., 2024; Yerushalmi & Green, 2009) that vary across the 24 hour day, including light, temperature, humidity and the rhythms of other organisms (Helm et al., 2017). Organisms evolve to maintain this alignment because environmental oscillations directly impact on fitness, provide timing information (i.e.…”

Section: Introductionmentioning

confidence: 99%

Testing the evolutionary drivers of malaria parasite rhythms and their consequences for host–parasite interactions

Holland,

Prior,

O'Donnell

et al. 2024

Evolutionary Applications

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Undertaking certain activities at the time of day that maximises fitness is assumed to explain the evolution of circadian clocks. Organisms often use daily environmental cues such as light and food availability to set the timing of their clocks. These cues may be the environmental rhythms that ultimately determine fitness, act as proxies for the timing of less tractable ultimate drivers, or are used simply to maintain internal synchrony. While many pathogens/parasites undertake rhythmic activities, both the proximate and ultimate drivers of their rhythms are poorly understood. Explaining the roles of rhythms in infections offers avenues for novel interventions to interfere with parasite fitness and reduce the severity and spread of disease. Here, we perturb several rhythms in the hosts of malaria parasites to investigate why parasites align their rhythmic replication to the host's feeding‐fasting rhythm. We manipulated host rhythms governed by light, food or both, and assessed the fitness implications for parasites, and the consequences for hosts, to test which host rhythms represent ultimate drivers of the parasite's rhythm. We found that alignment with the host's light‐driven rhythms did not affect parasite fitness metrics. In contrast, aligning with the timing of feeding‐fasting rhythms may be beneficial for the parasite, but only when the host possess a functional canonical circadian clock. Because parasites in clock‐disrupted hosts align with the host's feeding‐fasting rhythms and yet derive no apparent benefit, our results suggest cue(s) from host food act as a proxy rather than being a key selective driver of the parasite's rhythm. Alternatively, parasite rhythmicity may only be beneficial because it promotes synchrony between parasite cells and/or allows parasites to align to the biting rhythms of vectors. Our results also suggest that interventions can disrupt parasite rhythms by targeting the proxies or the selective factors driving them without impacting host health.

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Insights into the Evolution of Circadian Clocks Gleaned from Bacteria

Cited by 6 publications

References 70 publications

Bacteria can anticipate the seasons: photoperiodism in cyanobacteria

Bacteria can anticipate the seasons: photoperiodism in cyanobacteria

Circadian Biology and the Neurovascular Unit

Testing the evolutionary drivers of malaria parasite rhythms and their consequences for host–parasite interactions

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