scholarly journals Transcriptional Control of Circadian Rhythms and Metabolism: A Matter of Time and Space

2020 ◽  
Vol 41 (5) ◽  
pp. 707-732 ◽  
Author(s):  
Yong Hoon Kim ◽  
Mitchell A Lazar
Keyword(s):  
Circadian Rhythms ◽  
Transcriptional Control ◽  
Environmental Changes ◽  
Adaptive Responses ◽  
3 Dimensional ◽  
Circadian Expression ◽  
Expression Of Genes ◽  
Future Challenges ◽  
Living Organisms ◽  
Life On Earth

Abstract All biological processes, living organisms, and ecosystems have evolved with the Sun that confers a 24-hour periodicity to life on Earth. Circadian rhythms arose from evolutionary needs to maximize daily organismal fitness by enabling organisms to mount anticipatory and adaptive responses to recurrent light-dark cycles and associated environmental changes. The clock is a conserved feature in nearly all forms of life, ranging from prokaryotes to virtually every cell of multicellular eukaryotes. The mammalian clock comprises transcription factors interlocked in negative feedback loops, which generate circadian expression of genes that coordinate rhythmic physiology. In this review, we highlight previous and recent studies that have advanced our understanding of the transcriptional architecture of the mammalian clock, with a specific focus on epigenetic mechanisms, transcriptomics, and 3-dimensional chromatin architecture. In addition, we discuss reciprocal ways in which the clock and metabolism regulate each other to generate metabolic rhythms. We also highlight implications of circadian biology in human health, ranging from genetic and environment disruptions of the clock to novel therapeutic opportunities for circadian medicine. Finally, we explore remaining fundamental questions and future challenges to advancing the field forward.

scholarly journals Advances and Promises of Epigenetics for Forest Trees

Forests ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 976 ◽  
Author(s):  
Joana Amaral ◽  
Zoé Ribeyre ◽  
Julien Vigneaud ◽  
Mamadou Dia Sow ◽  
Régis Fichot ◽  
...  
Keyword(s):  
Forest Management ◽  
Environmental Changes ◽  
Forest Trees ◽  
Adaptive Responses ◽  
Forest Research ◽  
Recent Advances ◽  
Future Challenges ◽  
Potential Applications ◽  
Management And Conservation ◽  
Forest Managers

The importance of tree genetic variability in the ability of forests to respond and adapt to environmental changes is crucial in forest management and conservation. Along with genetics, recent advances have highlighted “epigenetics” as an emerging and promising field of research for the understanding of tree phenotypic plasticity and adaptive responses. In this paper, we review recent advances in this emerging field and their potential applications for tree researchers and breeders, as well as for forest managers. First, we present the basics of epigenetics in plants before discussing its potential for trees. We then propose a bibliometric and overview of the literature on epigenetics in trees, including recent advances on tree priming. Lastly, we outline the promises of epigenetics for forest research and management, along with current gaps and future challenges. Research in epigenetics could use highly diverse paths to help forests adapt to global change by eliciting different innovative silvicultural approaches for natural- and artificial-based forest management.

Rethinking the clockwork: redox cycles and non-transcriptional control of circadian rhythms

2014 ◽  
Vol 42 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Lisa Wu ◽  
Akhilesh B. Reddy
Keyword(s):  
Circadian Rhythms ◽  
Redox Reactions ◽  
Transcriptional Control ◽  
Clock Genes ◽  
Feedback Loops ◽  
Core Group ◽  
Redox Cycles ◽  
Domains Of Life ◽  
Behavioural Phenotypes ◽  
Living Organisms

Circadian rhythms are a hallmark of living organisms, observable in all walks of life from primitive bacteria to highly complex humans. They are believed to have evolved to co-ordinate the timing of biological and behavioural processes to the changing environmental needs brought on by the progression of day and night through the 24-h cycle. Most of the modern study of circadian rhythms has centred on so-called TTFLs (transcription–translation feedback loops), wherein a core group of ‘clock’ genes, capable of negatively regulating themselves, produce oscillations with a period of approximately 24 h. Recently, however, the prevalence of the TTFL paradigm has been challenged by a series of findings wherein circadian rhythms, in the form of redox reactions, persist in the absence of transcriptional cycles. We have found that circadian cycles of oxidation and reduction are conserved across all domains of life, strongly suggesting that non-TTFL mechanisms work in parallel with the canonical genetic processes of timekeeping to generate the cyclical cellular and behavioural phenotypes that we commonly recognize as circadian rhythms.

scholarly journals Circadian Rhythms in Cyanobacteria

2015 ◽  
Vol 79 (4) ◽  
pp. 373-385 ◽  
Author(s):  
Susan E. Cohen ◽  
Susan S. Golden
Keyword(s):  
Circadian Rhythms ◽  
Circadian Clock ◽  
Environmental Changes ◽  
Content Type ◽  
Interactive Network ◽  
Cyanobacterial Species ◽  
Rotation Of The Earth ◽  
Eukaryotic Organisms ◽  
Life On Earth ◽  
Pcc 7942

SUMMARYLife on earth is subject to daily and predictable fluctuations in light intensity, temperature, and humidity created by rotation of the earth. Circadian rhythms, generated by a circadian clock, control temporal programs of cellular physiology to facilitate adaptation to daily environmental changes. Circadian rhythms are nearly ubiquitous and are found in both prokaryotic and eukaryotic organisms. Here we introduce the molecular mechanism of the circadian clock in the model cyanobacteriumSynechococcus elongatusPCC 7942. We review the current understanding of the cyanobacterial clock, emphasizing recent work that has generated a more comprehensive understanding of how the circadian oscillator becomes synchronized with the external environment and how information from the oscillator is transmitted to generate rhythms of biological activity. These results have changed how we think about the clock, shifting away from a linear model to one in which the clock is viewed as an interactive network of multifunctional components that are integrated into the context of the cell in order to pace and reset the oscillator. We conclude with a discussion of how this basic timekeeping mechanism differs in other cyanobacterial species and how information gleaned from work in cyanobacteria can be translated to understanding rhythmic phenomena in other prokaryotic systems.

scholarly journals Circadian Rhythm: Potential Therapeutic Target for Atherosclerosis and Thrombosis

2021 ◽  
Vol 22 (2) ◽  
pp. 676
Author(s):  
Andy W. C. Man ◽  
Huige Li ◽  
Ning Xia
Keyword(s):  
Circadian Rhythm ◽  
Cardiovascular Diseases ◽  
Circadian Rhythms ◽  
Circadian Clock ◽  
Therapeutic Target ◽  
Environmental Changes ◽  
Clock Genes ◽  
Vascular System ◽  
Peripheral Tissues ◽  
Inflammatory Processes

Every organism has an intrinsic biological rhythm that orchestrates biological processes in adjusting to daily environmental changes. Circadian rhythms are maintained by networks of molecular clocks throughout the core and peripheral tissues, including immune cells, blood vessels, and perivascular adipose tissues. Recent findings have suggested strong correlations between the circadian clock and cardiovascular diseases. Desynchronization between the circadian rhythm and body metabolism contributes to the development of cardiovascular diseases including arteriosclerosis and thrombosis. Circadian rhythms are involved in controlling inflammatory processes and metabolisms, which can influence the pathology of arteriosclerosis and thrombosis. Circadian clock genes are critical in maintaining the robust relationship between diurnal variation and the cardiovascular system. The circadian machinery in the vascular system may be a novel therapeutic target for the prevention and treatment of cardiovascular diseases. The research on circadian rhythms in cardiovascular diseases is still progressing. In this review, we briefly summarize recent studies on circadian rhythms and cardiovascular homeostasis, focusing on the circadian control of inflammatory processes and metabolisms. Based on the recent findings, we discuss the potential target molecules for future therapeutic strategies against cardiovascular diseases by targeting the circadian clock.

scholarly journals Transcriptome changes reveal the genetic mechanisms of the reproductive plasticity of workers in lower termites

BMC Genomics ◽  
2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Chenxu Ye ◽  
Humaira Rasheed ◽  
Yuehua Ran ◽  
Xiaojuan Yang ◽  
Lianxi Xing ◽  
...  
Keyword(s):  
Gene Expression ◽  
Signal Transduction ◽  
Molecular Mechanisms ◽  
Environmental Changes ◽  
Mapk Pathway ◽  
Specific Expression ◽  
Expression Of Genes ◽  
Genetic Mechanisms ◽  
Ecological Success ◽  
Reproductive Plasticity

Abstract Background The reproductive plasticity of termite workers provides colonies with tremendous flexibility to respond to environmental changes, which is the basis for evolutionary and ecological success. Although it is known that all colony members share the same genetic background and that differences in castes are caused by differences in gene expression, the pattern of the specific expression of genes involved in the differentiation of workers into reproductives remains unclear. In this study, the isolated workers of Reticulitermes labralis developed into reproductives, and then comparative transcriptomes were used for the first time to reveal the molecular mechanisms underlying the reproductive plasticity of workers. Results We identified 38,070 differentially expressed genes and found a pattern of gene expression involved in the differentiation of the workers into reproductives. 12, 543 genes were specifically upregulated in the isolated workers. Twenty-five signal transduction pathways classified into environmental information processing were related to the differentiation of workers into reproductives. Ras functions as a signalling switch regulates the reproductive plasticity of workers. The catalase gene which is related to longevity was up-regulated in reproductives. Conclusion We demonstrate that workers leaving the natal colony can induce the expression of stage-specific genes in the workers, which leads to the differentiation of workers into reproductives and suggests that the signal transduction along the Ras-MAPK pathway crucially controls the reproductive plasticity of the workers. This study also provides an important model for revealing the molecular mechanism of longevity changes.

scholarly journals Survival is reduced when endogenous period deviates from 24 h in a non-human primate, supporting the circadian resonance theory

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Clara Hozer ◽  
Martine Perret ◽  
Samuel Pavard ◽  
Fabien Pifferi
Keyword(s):  
Circadian Rhythms ◽  
Circadian Clock ◽  
Microcebus Murinus ◽  
Circadian Period ◽  
Biological Functions ◽  
Resonance Theory ◽  
Aging Research ◽  
Mouse Lemurs ◽  
Living Organisms ◽  
Human Primate

Abstract Circadian rhythms are ubiquitous attributes across living organisms and allow the coordination of internal biological functions with optimal phases of the environment, suggesting a significant adaptive advantage. The endogenous period called tau lies close to 24 h and is thought to be implicated in individuals’ fitness: according to the circadian resonance theory, fitness is reduced when tau gets far from 24 h. In this study, we measured the endogenous period of 142 mouse lemurs (Microcebus murinus), and analyzed how it is related to their survival. We found different effects according to sex and season. No impact of tau on mortality was found in females. However, in males, the deviation of tau from 24 h substantially correlates with an increase in mortality, particularly during the inactive season (winter). These results, comparable to other observations in mice or drosophila, show that captive gray mouse lemurs enjoy better fitness when their circadian period closely matches the environmental periodicity. In addition to their deep implications in health and aging research, these results raise further ecological and evolutionary issues regarding the relationships between fitness and circadian clock.

scholarly journals The inorganic chemicals that surround us: role of tellurium, selenium and zinc on behavioural functions in mammals

2021 ◽  
Vol 9 (2) ◽  
pp. 151-163
Author(s):  
Edgardo O. Alvarez ◽  
Osvaldo J. Sacchi ◽  
Silvia G. Ratti
Keyword(s):  
Social Activity ◽  
Phenotypic Expression ◽  
Adaptive Responses ◽  
Biologic Effects ◽  
Continuous Interaction ◽  
Inorganic Chemical ◽  
Living Organisms ◽  
La Rioja ◽  
Toxic Concentrations

Living organisms live in continuous interaction with its environment. During this process changes in one can induce adaptive responses on the other. Many factors in the environment have been studied with the notorious distinction of been rare or to be of high intensity strength in its interaction with living organisms. However, little attention has been put on some factors that have constant interaction with organisms but usually have low intensity strength, such as the case of the inorganic chemical environment that surrounds us. In this review, the interaction between the chemical element and living organisms is discussed under a theoretical model of interaction between compartments, giving attention to tellurium (Te), zinc (Zn) and selenium (Se) on some cognitive functions in human and animals. After studies in our laboratory of the phenotypic expression of the HSR (Hand Skill Relative) gene in school children community living in geographic zone rich in minerals and mines of La Rioja province, Argentine, where Te was found to be in higher non-toxic concentrations, a translational experimental model to maturing rats exposed to this trace element was made. Te was found to increase some parameters related to locomotion in an open field induced by novelty and exploratory motivation. At the same time, inhibition of lateralized responses, survival responses and social activity was also observed. Some of these changes, particularly those related to lateralization had similarity with that found previously in children of La Rioja province. Discussion of similarities and discrepancies of biologic effects between animals and humans, about the possible meaning of Te and its interaction with Zn and Se with relevance to humans was analyzed.

scholarly journals Nanotechnology Innovations in Construction Industry and Environmental Sustainability

2019 ◽  
Vol 8 (11S) ◽  
pp. 286-291
Keyword(s):  
Construction Industry ◽  
Environmental Sustainability ◽  
Research Review ◽  
Environmental Damage ◽  
The Sustainable Development ◽  
Future Challenges ◽  
Future Potential ◽  
Living Organisms ◽  
The Impact ◽  
Near Future

Nanotechnology is a speedily increasing and innovating range of research, where advanced characteristics of resources manufactures on the nanoscale can be exploited as advantages for people at large through various methods or mechanisms of construction. Being a varied technical and scientific arena that brings and covers numerous application kinds, the contribution of nanotechnological innovations is immense for various sectors of construction industries. It also possesses a large future potential for ecological efficiency, which is dire need of the hour. In construction industry there are many factors involved to achieve the major goal of sustainability like smart design, planning through which energy can be saved, resource usage can be reduced and environmental damage can be avoided. No doubt, the application of nanotechnology materials and its various causes on the atmosphere and living organisms are not clearly defined yet which can become a problem. For instance, leakage of materials into the water resources, and seas, as well, discharge of nanoparticles into the air generating dust and exposure to harmful materials during various construction, maintenance and use etc. Considering tremendous revolution in Nanotechnological field there is an important aspect in relation to the impact of nanoparticles and nanomaterials on human health and environment which should be discussed at length. This paper intends to give a research review of current and near future, safety and eco-efficiency applications of nanotechnology to not only improve and maintain but also deal with certain future challenges and directions related to the sustainable development.

scholarly journals Interaction between photoperiod and variation in circadian rhythms in tomato

2022 ◽  
Author(s):  
Yanli Xiang ◽  
Thomas Sapir ◽  
Pauline Rouillard ◽  
Marina Ferrand ◽  
Jose M Jimenez-Gomez
Keyword(s):  
Seasonal Variation ◽  
Circadian Rhythms ◽  
Phase Shift ◽  
Circadian Clock ◽  
Environmental Changes ◽  
Circadian Clocks ◽  
Biological Processes ◽  
Near Isogenic Lines ◽  
Transcriptomic Profiling ◽  
Isogenic Lines

Many biological processes follow circadian rhythmicity and are controlled by the circadian clock. Predictable environmental changes such as seasonal variation in photoperiod can modulate circadian rhythms, allowing organisms to adjust to the time of the year. Modification of circadian clocks is especially relevant in crops to enhance their cultivability in specific regions by changing their sensibility to photoperiod. In tomato, the appearance of mutations in EMPFINDLICHER IM DUNKELROTEN LICHT 1 (EID1, Solyc09g075080) and NIGHT LIGHT-INDUCIBLE AND CLOCK-REGULATED GENE 2 (LNK2, Solyc01g068560) during domestication delayed its circadian rhythms, and allowed its expansion outside its equatorial origin. Here we study how variation in circadian rhythms in tomato affects its perception of photoperiod. To do this, we create near isogenic lines carrying combinations of wild alleles of EID1 and LNK2 and perform transcriptomic profiling under two different photoperiods. We observe that EID1, but not LNK2, has a large effect on the tomato transcriptome and its response to photoperiod. This large effect of EID1 is likely a consequence of the global phase shift elicited by this gene in tomato's circadian rhythms.

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