scholarly journals Ticking over: Circadian systems across the kingdoms of life

2011 ◽  
Vol 33 (1) ◽  
pp. 12-15
Author(s):  
Neil Dalchau ◽  
Alex A.R. Webb
Keyword(s):  
Circadian Clock ◽  
Model Organisms ◽  
Molecular Architecture ◽  
General Phenomenon ◽  
Daily Rhythms ◽  
Fitness Benefits ◽  
Multidisciplinary Studies ◽  
The Many

The ability to anticipate the day–night cycle and direct physiology accordingly has proven to be a general phenomenon across all kingdoms of life. Considerable fitness benefits are conferred by an internal 24hour clock, which is known as a circadian clock. Extensive multidisciplinary studies in a range of model organisms have elucidated many of the components involved in generating and sustaining daily rhythms. When comparing the circadian systems across the kingdoms, it is fascinating to observe the commonalities and differences in their molecular architecture, and the many adaptations which have evolved to deal with organismspecific requirements of biological timing.

scholarly journals The circadian clock uses different environmental time cues to synchronize emergence and locomotion of the solitary bee Osmia bicornis

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Katharina Beer ◽  
Mariela Schenk ◽  
Charlotte Helfrich-Förster ◽  
Andrea Holzschuh
Keyword(s):  
Circadian Clock ◽  
Circadian System ◽  
Evolutionary Adaptation ◽  
Solitary Bee ◽  
Daily Rhythms ◽  
Osmia Bicornis ◽  
Cavity Nesting ◽  
Impact On Survival ◽  
Life On Earth ◽  
And Behavior

AbstractLife on earth adapted to the daily reoccurring changes in environment by evolving an endogenous circadian clock. Although the circadian clock has a crucial impact on survival and behavior of solitary bees, many aspects of solitary bee clock mechanisms remain unknown. Our study is the first to show that the circadian clock governs emergence in Osmia bicornis, a bee species which overwinters as adult inside its cocoon. Therefore, its eclosion from the pupal case is separated by an interjacent diapause from its emergence in spring. We show that this bee species synchronizes its emergence to the morning. The daily rhythms of emergence are triggered by temperature cycles but not by light cycles. In contrast to this, the bee’s daily rhythms in locomotion are synchronized by light cycles. Thus, we show that the circadian clock of O. bicornis is set by either temperature or light, depending on what activity is timed. Light is a valuable cue for setting the circadian clock when bees have left the nest. However, for pre-emerged bees, temperature is the most important cue, which may represent an evolutionary adaptation of the circadian system to the cavity-nesting life style of O. bicornis.

scholarly journals Daily rhythms in gene expression of the human parasite Schistosoma mansoni

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Kate A. Rawlinson ◽  
Adam J. Reid ◽  
Zhigang Lu ◽  
Patrick Driguez ◽  
Anna Wawer ◽  
...  
Keyword(s):  
Gene Expression ◽  
Schistosoma Mansoni ◽  
Circadian Clock ◽  
Drug Targets ◽  
Clock Genes ◽  
Biological Rhythms ◽  
Active Phase ◽  
Egg Laying ◽  
Daily Rhythms ◽  
Metazoan Parasites

Abstract Background The consequences of the earth’s daily rotation have led to 24-h biological rhythms in most organisms. Even some parasites are known to have daily rhythms, which, when in synchrony with host rhythms, can optimise their fitness. Understanding these rhythms may enable the development of control strategies that take advantage of rhythmic vulnerabilities. Recent work on protozoan parasites has revealed 24-h rhythms in gene expression, drug sensitivity and the presence of an intrinsic circadian clock; however, similar studies on metazoan parasites are lacking. To address this, we investigated if a metazoan parasite has daily molecular oscillations, whether they reveal how these longer-lived organisms can survive host daily cycles over a lifespan of many years and if animal circadian clock genes are present and rhythmic. We addressed these questions using the human blood fluke Schistosoma mansoni that lives in the vasculature for decades and causes the tropical disease schistosomiasis. Results Using round-the-clock transcriptomics of male and female adult worms collected from experimentally infected mice, we discovered that ~ 2% of its genes followed a daily pattern of expression. Rhythmic processes included a stress response during the host’s active phase and a ‘peak in metabolic activity’ during the host’s resting phase. Transcriptional profiles in the female reproductive system were mirrored by daily patterns in egg laying (eggs are the main drivers of the host pathology). Genes cycling with the highest amplitudes include predicted drug targets and a vaccine candidate. These 24-h rhythms may be driven by host rhythms and/or generated by a circadian clock; however, orthologs of core clock genes are missing and secondary clock genes show no 24-h rhythmicity. Conclusions There are daily rhythms in the transcriptomes of adult S. mansoni, but they appear less pronounced than in other organisms. The rhythms reveal temporally compartmentalised internal processes and host interactions relevant to within-host survival and between-host transmission. Our findings suggest that if these daily rhythms are generated by an intrinsic circadian clock then the oscillatory mechanism must be distinct from that in other animals. We have shown which transcripts oscillate at this temporal scale and this will benefit the development and delivery of treatments against schistosomiasis.

scholarly journals The Circadian Clock, the Brain, and COVID-19: The Cases of Olfaction and the Timing of Sleep

2021 ◽  
pp. 074873042110312
Author(s):  
Rachel S. Herz ◽  
Erik D. Herzog ◽  
Martha Merrow ◽  
Sara B. Noya
Keyword(s):  
Ischemic Stroke ◽  
Cognitive Function ◽  
Human Brain ◽  
Circadian Clock ◽  
Clinical Data ◽  
Circadian Clocks ◽  
Olfactory Sensitivity ◽  
Daily Rhythms ◽  
Sense Of Smell ◽  
The Brain

Daily rhythms of behavior and neurophysiology are integral to the circadian clocks of all animals. Examples of circadian clock regulation in the human brain include daily rhythms in sleep-wake, cognitive function, olfactory sensitivity, and risk for ischemic stroke, all of which overlap with symptoms displayed by many COVID-19 patients. Motivated by the relatively unexplored, yet pervasive, overlap between circadian functions and COVID-19 neurological symptoms, this perspective piece uses daily variations in the sense of smell and the timing of sleep and wakefulness as illustrative examples. We propose that time-stamping clinical data and testing may expand and refine diagnosis and treatment of COVID-19.

scholarly journals Building Bridges from Genome to Phenome: Molecules, Methods and Models—An Introduction to the Symposium

2020 ◽  
Vol 60 (2) ◽  
pp. 261-266 ◽  
Author(s):  
Karen G Burnett ◽  
David S Durica ◽  
Donald L Mykles ◽  
Jonathon H Stillman
Keyword(s):  
White Paper ◽  
Model Organisms ◽  
Emergent Properties ◽  
Environment Interaction ◽  
Biological Organization ◽  
Future Directions ◽  
Central Focus ◽  
Genotype Environment Interaction ◽  
Scientific Disciplines ◽  
The Many

Synopsis How stable genotypes interact with their environment to generate phenotypic variation that can be acted upon by evolutionary and ecological forces is a central focus of research across many scientific disciplines represented within SICB. The Building Bridges Symposium brought together scientists using a variety of organisms, methods, and levels of biological organization to study the emergent properties of genomes. Workshops associated with the Symposium aimed to identify the leading edges and major barriers to research in this field, and to recommend future directions that might accelerate the pace of progress. The papers included in this Symposium volume draw attention to the strength of using comparative approaches in non-model organisms to study the many aspects of genotype–environment interaction that drive phenotype variation. These contributions and the concluding white paper also illustrate the need for novel conceptual frameworks that can bridge and accommodate data and conclusions from the broad range of study systems employed by comparative and integrative biologists to address genome-to-phenome questions.

scholarly journals Deep sequencing analysis of the circadian transcriptome of the jewel wasp Nasonia vitripennis

2016 ◽  
Author(s):  
Nathaniel J. Davies ◽  
Eran Tauber
Keyword(s):  
Circadian Clock ◽  
Deep Sequencing ◽  
Clock Genes ◽  
Model System ◽  
Model Organisms ◽  
Constant Darkness ◽  
Sequencing Analysis ◽  
Rna Seq ◽  
Nasonia Vitripennis ◽  
Deep Sequencing Analysis

AbstractThe study of the circadian clock has benefited greatly from using Drosophila as a model system. Yet, accumulating evidence suggests that the fly might not be the canonical insect model. Here, we have analysed the circadian transcriptome of the Jewl wasp Nasonia vitripennis by using RNA-seq in both constant darkness (DD) and constant light (LL, the wasps are rhythmic in LL with period shortening). At a relatively stringent FDR (q < 0.1), we identified 1,057 cycling transcripts in DD and 929 in LL (fraction of 6.7% and 5.9% of all transcripts analysed in DD and LL respectively). Although there was little similarity between cycling genes in Drosophila and Nasonia, the functions fulfilled by cycling transcripts were similar in both species. Of the known Drosophila core clock genes, only pdp1e, shaggy and Clok showed a significant cycling in Nasonia, underscoring the importance of studying the clock in non-model organisms.

scholarly journals Circadian Interactomics: How Research Into Protein-Protein Interactions Beyond the Core Clock Has Influenced the Model of Circadian Timekeeping

2021 ◽  
pp. 074873042110146
Author(s):  
Alexander E. Mosier ◽  
Jennifer M. Hurley
Keyword(s):  
Circadian Clock ◽  
Protein Interactions ◽  
Large Scale ◽  
Protein Complexes ◽  
Model Organisms ◽  
Protein Protein Interactions ◽  
Macromolecular Complexes ◽  
The Core ◽  
Circadian Control ◽  
Macromolecular Protein

The circadian clock is the broadly conserved, protein-based, timekeeping mechanism that synchronizes biology to the Earth’s 24-h light-dark cycle. Studies of the mechanisms of circadian timekeeping have placed great focus on the role that individual protein-protein interactions play in the creation of the timekeeping loop. However, research has shown that clock proteins most commonly act as part of large macromolecular protein complexes to facilitate circadian control over physiology. The formation of these complexes has led to the large-scale study of the proteins that comprise these complexes, termed here “circadian interactomics.” Circadian interactomic studies of the macromolecular protein complexes that comprise the circadian clock have uncovered many basic principles of circadian timekeeping as well as mechanisms of circadian control over cellular physiology. In this review, we examine the wealth of knowledge accumulated using circadian interactomics approaches to investigate the macromolecular complexes of the core circadian clock, including insights into the core mechanisms that impart circadian timing and the clock’s regulation of many physiological processes. We examine data acquired from the investigation of the macromolecular complexes centered on both the activating and repressing arm of the circadian clock and from many circadian model organisms.

scholarly journals The Mammalian Circadian Timing System and the Suprachiasmatic Nucleus as Its Pacemaker

Biology ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 13 ◽  
Author(s):  
Michael H. Hastings ◽  
Elizabeth S. Maywood ◽  
Marco Brancaccio
Keyword(s):  
Circadian Clock ◽  
Suprachiasmatic Nucleus ◽  
Higher Plants ◽  
Molecular Genetic ◽  
Model Organisms ◽  
Cellular Mechanisms ◽  
Molecular Genetic Basis ◽  
New Directions ◽  
Circadian Timing System ◽  
Definition Of

The past twenty years have witnessed the most remarkable breakthroughs in our understanding of the molecular and cellular mechanisms that underpin circadian (approximately one day) time-keeping. Across model organisms in diverse taxa: cyanobacteria (Synechococcus), fungi (Neurospora), higher plants (Arabidopsis), insects (Drosophila) and mammals (mouse and humans), a common mechanistic motif of delayed negative feedback has emerged as the Deus ex machina for the cellular definition of ca. 24 h cycles. This review will consider, briefly, comparative circadian clock biology and will then focus on the mammalian circadian system, considering its molecular genetic basis, the properties of the suprachiasmatic nucleus (SCN) as the principal circadian clock in mammals and its role in synchronising a distributed peripheral circadian clock network. Finally, it will consider new directions in analysing the cell-autonomous and circuit-level SCN clockwork and will highlight the surprising discovery of a central role for SCN astrocytes as well as SCN neurons in controlling circadian behaviour.

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