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Baruah D, Marak CNK, Roy A, Gohain D, Kumar A, Das P, Borkovich KA, Tamuli R. Multiple calcium signaling genes play a role in the circadian period of Neurospora crassa. FEMS Microbiol Lett 2023; 370:fnad044. [PMID: 37193664 PMCID: PMC10237334 DOI: 10.1093/femsle/fnad044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 04/12/2023] [Accepted: 05/15/2023] [Indexed: 05/18/2023] Open
Abstract
The Ca2+ signaling genes cpe-1, plc-1, ncs-1, splA2, camk-1, camk-2, camk-3, camk-4, cmd, and cnb-1 are necessary for a normal circadian period length in Neurospora crassa. In addition, the Q10 values ranged between 0.8 and 1.2 for the single mutants lacking cpe-1, splA2, camk-1, camk-2, camk-3, camk-4, and cnb-1, suggesting that the circadian clock exhibits standard temperature compensation. However, the Q10 value for the ∆plc-1 mutant was 1.41 at 25 and 30 °C, 1.53 and 1.40 for the ∆ncs-1 mutant at 20 and 25 °C, and at 20 and 30 °C, respectively, suggesting a partial loss of temperature compensation in these two mutants. Moreover, expression of frq, a regulator of the circadian period, and the blue light receptor wc-1, were increased >2-fold in the Δplc-1, ∆plc-1; ∆cpe-1, and the ∆plc-1; ∆splA2 mutants at 20 °C. The frq mRNA level was increased >2-fold in the Δncs-1 mutant compared to the ras-1bd strain at 20 °C. Therefore, multiple Ca2+ signaling genes regulate the circadian period, by influencing expression of the frq and wc-1 genes that are critical for maintaining the normal circadian period length in N. crassa.
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Affiliation(s)
- Darshana Baruah
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Christy Noche K Marak
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Avishek Roy
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Dibakar Gohain
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Ajeet Kumar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Pallavi Das
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Katherine A Borkovich
- Department of Microbiology and Plant Pathology, Institute for Integrative Genome Biology, College of Natural and Agricultural Sciences, University of California Riverside, Riverside 92521, CA, USA
| | - Ranjan Tamuli
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
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Gagné F, Houda H, André C. Altered mitochondria oscillations and circadian changes in NADH levels in freshwaters mussels exposed to cadmium. Comp Biochem Physiol C Toxicol Pharmacol 2022; 260:109420. [PMID: 35902061 DOI: 10.1016/j.cbpc.2022.109420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 06/27/2022] [Accepted: 07/20/2022] [Indexed: 11/29/2022]
Affiliation(s)
- F Gagné
- Aquatic Contaminants Research Division, Environnement and Climate Change Canada, 105 McGill, Montreal, Québec H2Y 2E7, Canada.
| | - H Houda
- Aquatic Contaminants Research Division, Environnement and Climate Change Canada, 105 McGill, Montreal, Québec H2Y 2E7, Canada
| | - C André
- Aquatic Contaminants Research Division, Environnement and Climate Change Canada, 105 McGill, Montreal, Québec H2Y 2E7, Canada
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The Cell Division Cycle of Euglena gracilis Indicates That the Level of Circadian Plasticity to the External Light Regime Changes in Prolonged-Stationary Cultures. PLANTS 2021; 10:plants10071475. [PMID: 34371678 PMCID: PMC8309271 DOI: 10.3390/plants10071475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 07/12/2021] [Accepted: 07/12/2021] [Indexed: 11/17/2022]
Abstract
In unicellular photosynthetic organisms, circadian rhythm is tightly linked to gating of cell cycle progression, and is entrained by light signal. As several organisms obtain a fitness advantage when the external light/dark cycle matches their endogenous period, and aging alters circadian rhythms, senescence phenotypes of the microalga Euglena gracilis of different culture ages were characterized with respect to the cell division cycle. We report here the effects of prolonged-stationary-phase conditions on the cell division cycles of E. gracilis under non-24-h light/dark cycles (T-cycles). Under T-cycles, cells established from 1-month-old and 2-month-old cultures produced lower cell concentrations after cultivation in the fresh medium than cells from 1-week-old culture. This decrease was not due to higher concentrations of dead cells in the populations, suggesting that cells of different culture ages differ in their capacity for cell division. Cells from 1-week-old cultures had a shorter circadian period of their cell division cycle under shortened T-cycles than aged cells. When algae were transferred to free-running conditions after entrainment to shortened T-cycles, the young cells showed the peak growth rate at a time corresponding to the first subjective night, but the aged cells did not. This suggests that circadian rhythms are more plastic in younger E. gracilis cells.
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Tai L, Li BB, Nie XM, Zhang PP, Hu CH, Zhang L, Liu WT, Li WQ, Chen KM. Calmodulin Is the Fundamental Regulator of NADK-Mediated NAD Signaling in Plants. FRONTIERS IN PLANT SCIENCE 2019; 10:681. [PMID: 31275331 PMCID: PMC6593290 DOI: 10.3389/fpls.2019.00681] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 05/06/2019] [Indexed: 05/02/2023]
Abstract
Calcium (Ca2+) signaling and nicotinamide adenine dinucleotide (NAD) signaling are two basic signal regulation pathways in organisms, playing crucial roles in signal transduction, energy metabolism, stress tolerance, and various developmental processes. Notably, calmodulins (CaMs) and NAD kinases (NADKs) are important hubs for connecting these two types of signaling networks, where CaMs are the unique activators of NADKs. NADK is a key enzyme for NADP (including NADP+ and NADPH) biosynthesis by phosphorylating NAD (including NAD+ and NADH) and therefore, maintains the balance between NAD pool and NADP pool through an allosteric regulation mode. In addition, the two respective derivatives from NAD+ (substrate of NADK) and NADP+ (product of NADK), cyclic ADP-ribose (cADPR) and nicotinic acid adenine dinucleotide phosphate (NAADP), have been considered to be the important messengers for intracellular Ca2+ homeostasis which could finally influence the combination between CaM and NADK, forming a feedback regulation mechanism. In this review article, we briefly summarized the major research advances related to the feedback regulation pathway, which is activated by the interaction of CaM and NADK during plant development and signaling. The theories and fact will lay a solid foundation for further studies related to CaM and NADK and their regulatory mechanisms as well as the NADK-mediated NAD signaling behavior in plant development and response to stress.
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Affiliation(s)
- Li Tai
- State Key Laboratory of Crop Stress Biology in Arid Area/College of Life Sciences, Northwest A&F University, Yangling, China
| | - Bin-Bin Li
- State Key Laboratory of Crop Stress Biology in Arid Area/College of Life Sciences, Northwest A&F University, Yangling, China
| | - Xiu-Min Nie
- State Key Laboratory of Crop Stress Biology in Arid Area/College of Life Sciences, Northwest A&F University, Yangling, China
| | - Peng-Peng Zhang
- State Key Laboratory of Crop Stress Biology in Arid Area/College of Life Sciences, Northwest A&F University, Yangling, China
| | - Chun-Hong Hu
- State Key Laboratory of Crop Stress Biology in Arid Area/College of Life Sciences, Northwest A&F University, Yangling, China
- Department of General Biology, College of Life Science and Agronomy, Zhoukou Normal University, Zhoukou, China
| | - Lu Zhang
- State Key Laboratory of Crop Stress Biology in Arid Area/College of Life Sciences, Northwest A&F University, Yangling, China
| | - Wen-Ting Liu
- State Key Laboratory of Crop Stress Biology in Arid Area/College of Life Sciences, Northwest A&F University, Yangling, China
| | - Wen-Qiang Li
- State Key Laboratory of Crop Stress Biology in Arid Area/College of Life Sciences, Northwest A&F University, Yangling, China
| | - Kun-Ming Chen
- State Key Laboratory of Crop Stress Biology in Arid Area/College of Life Sciences, Northwest A&F University, Yangling, China
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Abstract
Mounting evidence in recent years supports the extensive interaction between the circadian and redox systems. The existence of such a relationship is not surprising because most organisms, be they diurnal or nocturnal, display daily oscillations in energy intake, locomotor activity, and exposure to exogenous and internally generated oxidants. The transcriptional clock controls the levels of many antioxidant proteins and redox-active cofactors, and, conversely, the cellular redox poise has been shown to feed back to the transcriptional oscillator via redox-sensitive transcription factors and enzymes. However, the circadian cycles in the S-sulfinylation of the peroxiredoxin (PRDX) proteins constituted the first example of an autonomous circadian redox oscillation, which occurred independently of the transcriptional clock. Importantly, the high phylogenetic conservation of these rhythms suggests that they might predate the evolution of the transcriptional oscillator, and therefore could be a part of a primordial circadian redox/metabolic oscillator. This discovery forced the reappraisal of the dogmatic transcription-centered view of the clockwork and opened a new avenue of research. Indeed, the investigation into the links between the circadian and redox systems is still in its infancy, and many important questions remain to be addressed.
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Shape-based separation of microalga Euglena gracilis using inertial microfluidics. Sci Rep 2017; 7:10802. [PMID: 28883551 PMCID: PMC5589772 DOI: 10.1038/s41598-017-10452-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 08/09/2017] [Indexed: 12/27/2022] Open
Abstract
Euglena gracilis (E. gracilis) has been proposed as one of the most attractive microalgae species for biodiesel and biomass production, which exhibits a number of shapes, such as spherical, spindle-shaped, and elongated. Shape is an important biomarker for E. gracilis, serving as an indicator of biological clock status, photosynthetic and respiratory capacity, cell-cycle phase, and environmental condition. The ability to prepare E. gracilis of uniform shape at high purities has significant implications for various applications in biological research and industrial processes. Here, we adopt a label-free, high-throughput, and continuous technique utilizing inertial microfluidics to separate E. gracilis by a key shape parameter-cell aspect ratio (AR). The microfluidic device consists of a straight rectangular microchannel, a gradually expanding region, and five outlets with fluidic resistors, allowing for inertial focusing and ordering, enhancement of the differences in cell lateral positions, and accurate separation, respectively. By making use of the shape-activated differences in lateral inertial focusing dynamic equilibrium positions, E. gracilis with different ARs ranging from 1 to 7 are directed to different outlets.
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Ozasa K, Won J, Song S, Tamaki S, Ishikawa T, Maeda M. Temporal change of photophobic step-up responses of Euglena gracilis investigated through motion analysis. PLoS One 2017; 12:e0172813. [PMID: 28234984 PMCID: PMC5325543 DOI: 10.1371/journal.pone.0172813] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 02/09/2017] [Indexed: 11/28/2022] Open
Abstract
The adaptation to a strong light is one of the essential characteristics of green algae, yet lacking relatively the information about the photophobic responses of Eukaryotic microalgae. We investigated the photophobic step-up responses of Euglena gracilis over a time course of several hours with alternated repetition of blue-light pulse illumination and spatially patterned blue-light illumination. Four distinctive photophobic motions in response to strong blue light were identified in a trace image analysis, namely on-site rotation, running and tumbling, continuous circular swimming, and unaffected straightforward swimming. The cells cultured in autotrophic conditions under weak light showed mainly the on-site rotation response at the beginning of blue-light illumination, but they acquired more blue-light tolerant responses of running and tumbling, circular swimming, or straightforward swimming. The efficiency of escaping from a blue-light illuminated area improved markedly with the development of these photophobic motions. Time constant of 3.0 h was deduced for the evolution of photophobic responses of E. gracilis. The nutrient-rich metabolic status of the cells resulting from photosynthesis during the experiments, i.e., the accumulation of photosynthesized nutrient products in balance between formation and consumption, was the main factor responsible for the development of photophobic responses. The reduction-oxidation status in and around E. gracilis cells did not affect their photophobic responses significantly, unlike the case of photophobic responses and phototaxis of Chlamydomonas reinhardtii cells. This study shows that the evolution of photophobic motion type of E. gracilis is dominated mainly by the nutrient metabolic status of the cells. The fact suggests that the nutrient-rich cells have a higher threshold for switching the flagellar motion from straightforward swimming to rotation under a strong light.
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Affiliation(s)
| | - June Won
- Department of Mechanical Convergence Engineering, Hanyang University, Seongdong-gu, Seoul, Korea
| | - Simon Song
- Department of Mechanical Convergence Engineering, Hanyang University, Seongdong-gu, Seoul, Korea
- Institute of Nano Science and Technology, Hanyang University, Seongdong-gu, Seoul, Korea
| | - Shun Tamaki
- Department of Applied Bioscience and Biotechnology, Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Chiyoda-ku, Tokyo, Japan
| | - Takahiro Ishikawa
- Department of Applied Bioscience and Biotechnology, Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Chiyoda-ku, Tokyo, Japan
| | - Mizuo Maeda
- Bioengineering Lab, RIKEN, Wako, Saitama, Japan
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Abstract
The hypothalamic suprachiasmatic nucleus (SCN) has a pivotal role in the mammalian circadian clock. SCN neurons generate circadian rhythms in action potential firing frequencies and neurotransmitter release, and the core oscillation is thought to be driven by “clock gene” transcription-translation feedback loops. Cytosolic Ca2+mobilization followed by stimulation of various receptors has been shown to reset the gene transcription cycles in SCN neurons, whereas contribution of steady-state cytosolic Ca2+levels to the rhythm generation is unclear. Recently, circadian rhythms in cytosolic Ca2+levels have been demonstrated in cultured SCN neurons. The circadian Ca2+rhythms are driven by the release of Ca2+from ryanodine-sensitive internal stores and resistant to the blockade of action potentials. These results raise the possibility that gene translation/transcription loops may interact with autonomous Ca2+oscillations in the production of circadian rhythms in SCN neurons.
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Affiliation(s)
- Masayuki Ikeda
- Department of Molecular Behavioral Biology, Osaka Bioscience Institute, Suita, Osaka, Japan.
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9
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Abstract
Circadian clocks are cellular timekeeping mechanisms that coordinate behavior and physiology around the 24-h day in most living organisms. Misalignment of an organism's clock with its environment is associated with long-term adverse fitness consequences, as exemplified by the link between circadian disruption and various age-related diseases in humans. Current eukaryotic models of the circadian oscillator rely on transcription/translation feedback loop mechanisms, supplemented with accessory cytosolic loops that connect them to cellular physiology. However, mounting evidence is questioning the absolute necessity of transcription-based oscillators for circadian rhythmicity, supported by the recent discovery of oxidation-reduction cycles of peroxiredoxin proteins, which persist even in the absence of transcription. A more fundamental mechanism based on metabolic cycles could thus underlie circadian transcriptional and cytosolic rhythms, thereby promoting circadian oscillations to integral properties of cellular metabolism.
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Affiliation(s)
- Akhilesh B. Reddy
- Department of Clinical Neurosciences, University of Cambridge Metabolic Research Laboratories, National Institutes of Health Biomedical Research Center, and Wellcome Trust–Medical Research Council Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, United Kingdom
| | - Guillaume Rey
- Department of Clinical Neurosciences, University of Cambridge Metabolic Research Laboratories, National Institutes of Health Biomedical Research Center, and Wellcome Trust–Medical Research Council Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, United Kingdom
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Báez-Ruiz A, Díaz-Muñoz M. Chronic inhibition of endoplasmic reticulum calcium-release channels and calcium-ATPase lengthens the period of hepatic clock gene Per1. J Circadian Rhythms 2011; 9:6. [PMID: 21740569 PMCID: PMC3142245 DOI: 10.1186/1740-3391-9-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 07/08/2011] [Indexed: 11/17/2022] Open
Abstract
Background The role played by calcium as a regulator of circadian rhythms is not well understood. The effect of the pharmacological inhibition of the ryanodine receptor (RyR), inositol 1,4,5-trisphosphate receptor (IP3R), and endoplasmic-reticulum Ca2+-ATPase (SERCA), as well as the intracellular Ca2+-chelator BAPTA-AM was explored on the 24-h rhythmicity of the liver-clock protein PER1 in an experimental model of circadian synchronization by light and restricted-feeding schedules. Methods Liver explants from Period1-luciferase (Per1-luc) transgenic rats with either free food access or with a restricted meal schedule were treated for several days with drugs to inhibit the activity of IP3Rs (2-APB), RyRs (ryanodine), or SERCA (thapsigargin) as well as to suppress intracellular calcium fluctuations (BAPTA-AM). The period of Per1-luc expression was measured during and after drug administration. Results Liver explants from rats fed ad libitum showed a lengthened period in response to all the drugs tested. The pharmacological treatments of the explants from meal-entrained rats induced the same pattern, with the exception of the ryanodine treatment which, unexpectedly, did not modify the Per1-luc period. All effects associated with drug application were reversed after washout, indicating that none of the pharmacological treatments was toxic to the liver cultures. Conclusions Our data suggest that Ca2+ mobilized from internal deposits modulates the molecular circadian clock in the liver of rats entrained by light and by restricted meal access.
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Affiliation(s)
- Adrián Báez-Ruiz
- Departament de Neurobiología Moleculary Celular, Instituto de Neurobiología, UNAM-Juriquilla, Boulevard Juriquilla #3001, Apdo, Postal 1-1141, Querétaro, QRO, 76230, México.
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Goto K, Beneragama CK. Circadian clocks and antiaging: do non-aging microalgae like Euglena reveal anything? Ageing Res Rev 2010; 9:91-100. [PMID: 19800033 DOI: 10.1016/j.arr.2009.09.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Revised: 09/20/2009] [Accepted: 09/22/2009] [Indexed: 11/26/2022]
Abstract
Microalgae that divide symmetrically in all aspects do not age. While the evolutionary reason for this is obvious, little attention has been paid to the mechanistic explanations. A great deal of study involving many research fields would be needed to explain the mechanisms if we suppose that the immortality results from a lifelong sufficiency of defense from stress or from an essential part of counteracting age-accompanied damage accumulation. Additionally, little is known about the relationships between homeostasis and circadian clocks in antiaging, although each of these has been studied separately. Here, we present a conceptual generalization of those relationships, as suggested by evidence from non-aging microalgae, mainly Euglena. The circadian gating of mitosis and circadian temporal coordination may respectively reduce radiation- and disharmony-induced stress in which homeostasis cannot be involved, whereas circadian resistance rhythms may greatly help homeostatic defense from radiation- and metabolism-induced stress. We also briefly sketch mammalian aging research to compare the current status of knowledge with that of algal antiaging.
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Driessche TV. Circadian Rhythms in Three Unicellular Organisms. The Pecularities of the Organisms, the Evidence Brought on Rhythms and their Specific Practical Problems. Outline of Recent Hypotheses. BIOL RHYTHM RES 2008. [DOI: 10.1080/09291019409360309] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Abstract
Ultradian rhythms are those that cycle many times in a day and are therefore measured in hours, minutes, seconds or even fractions of a second. In yeasts and protists, a temperature-compensated clock with a period of about an hour (30-90 minutes) provides the time base upon which all central processes are synchronized. A 40-minute clock in yeast times metabolic, respiratory and transcriptional processes, and controls cell division cycle progression. This system has at its core a redox cycle involving NAD(P)H and dithiol-disulfide interconversions. It provides an archetype for biological time keeping on longer time scales (e.g. the daily cycles driven by circadian clocks) and underpins these rhythms, which cannot be understood in isolation. Ultradian rhythms are the foundation upon which the coherent functioning of the organism depends.
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Affiliation(s)
- David Lloyd
- Microbiology, School of Biosciences, Cardiff University, Wales, UK.
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MIWA I, KANAZAWA Y, ISHIKAWA K, HIROSE M. Synchronization of Mating Reactivity Rhythms in Populations ofParamecium bursaria. ACTA ACUST UNITED AC 2007. [DOI: 10.1111/j.1550-7408.1989.tb02676.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Hagiwara SY, Bolige A, Zhang Y, Takahashi M, Yamagishi A, Goto K. Circadian Gating of Photoinduction of Commitment to Cell-cycle Transitions in Relation to Photoperiodic Control of Cell Reproduction in Euglena¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2002)0760105cgopoc2.0.co2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Pollak N, Dölle C, Ziegler M. The power to reduce: pyridine nucleotides--small molecules with a multitude of functions. Biochem J 2007; 402:205-18. [PMID: 17295611 PMCID: PMC1798440 DOI: 10.1042/bj20061638] [Citation(s) in RCA: 498] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The pyridine nucleotides NAD and NADP play vital roles in metabolic conversions as signal transducers and in cellular defence systems. Both coenzymes participate as electron carriers in energy transduction and biosynthetic processes. Their oxidized forms, NAD+ and NADP+, have been identified as important elements of regulatory pathways. In particular, NAD+ serves as a substrate for ADP-ribosylation reactions and for the Sir2 family of NAD+-dependent protein deacetylases as well as a precursor of the calcium mobilizing molecule cADPr (cyclic ADP-ribose). The conversions of NADP+ into the 2'-phosphorylated form of cADPr or to its nicotinic acid derivative, NAADP, also result in the formation of potent intracellular calcium-signalling agents. Perhaps, the most critical function of NADP is in the maintenance of a pool of reducing equivalents which is essential to counteract oxidative damage and for other detoxifying reactions. It is well known that the NADPH/NADP+ ratio is usually kept high, in favour of the reduced form. Research within the past few years has revealed important insights into how the NADPH pool is generated and maintained in different subcellular compartments. Moreover, tremendous progress in the molecular characterization of NAD kinases has established these enzymes as vital factors for cell survival. In the present review, we summarize recent advances in the understanding of the biosynthesis and signalling functions of NAD(P) and highlight the new insights into the molecular mechanisms of NADPH generation and their roles in cell physiology.
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Affiliation(s)
- Nadine Pollak
- Department of Molecular Biology, University of Bergen, Thormøhlensgate 55, N-5008 Bergen, Norway
| | - Christian Dölle
- Department of Molecular Biology, University of Bergen, Thormøhlensgate 55, N-5008 Bergen, Norway
| | - Mathias Ziegler
- Department of Molecular Biology, University of Bergen, Thormøhlensgate 55, N-5008 Bergen, Norway
- To whom correspondence should be addressed (email )
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Bolige A, Goto K. Phytochrome-like responses in Euglena: A low fluence response that reorganizes the spectral dependence of the high irradiance response in long-day photoperiodic induction of cell division. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2007; 86:97-108. [PMID: 17029970 DOI: 10.1016/j.jphotobiol.2006.08.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2006] [Revised: 08/15/2006] [Accepted: 08/16/2006] [Indexed: 11/17/2022]
Abstract
Irradiance spectra change spatiotemporally, and angiosperms adapt accordingly, mainly through phytochromes. This study challenges the long-held belief that the flagellated alga Euglena gracilis lacks phytochromes and is therefore unaffected by spectral changes. We photoautotrophically cultured the alga under continuous light (LL), then transferred it to darkness. After about 26h in darkness, different irradiations for 3h enabled cell division in dark-arrested G2 cells evoking a high-irradiance response (HIR). The spectral characteristics of the irradiation during the LL period (pre-irradiation) defined the spectral sensitivity in the subsequent dark period. LL with light rich in the red spectrum led to a HIR to the red spectrum (R-HIR), whereas light rich in the far-red spectrum (FR) led to a FR-HIR. Finishing the period of pre-irradiation consisting of continuous cool-white fluorescent light (rich in R) by a FR pulse enhanced the characteristics of the FR-HIR 26h later. By contrast, a R pulse given at the end of the pre-irradiation rich in FR potentiated the R-HIR. The effects were completely photoreversible between R and FR with critical fluences of about 2mmolm(-2), satisfying the classic diagnostic feature of phytochromes. The action spectrum of the FR effect at the end of pre-irradiation consisting of continuous cool-white fluorescent light (rich in R) had a main peak at 740nm and a minor peak at 380nm, whereas antagonization of the FR effect had a main peak at 640nm and a minor peak at 480nm. Wavelengths of 610 and 670nm appeared in both spectra. We also demonstrated the photoreversibility of 380/640, 480/740, and (610 and 670)/(640 and 740) nm. We conclude that Euglena displays phytochrome-like responses similar to the 'shade avoidance' and 'end-of-day FR' effects reported in angiosperms.
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Affiliation(s)
- Aoen Bolige
- Laboratory of Biological Rhythms, Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080-8555, Japan
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Bolige A, Goto K. High irradiance responses involving photoreversible multiple photoreceptors as related to photoperiodic induction of cell division in Euglena. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2006; 86:109-20. [PMID: 17029971 DOI: 10.1016/j.jphotobiol.2006.08.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2006] [Revised: 08/15/2006] [Accepted: 08/16/2006] [Indexed: 11/27/2022]
Abstract
Little is known about the photoreceptors involved in the photoperiodism of unicellular organisms, which we elucidated by deriving their action spectra. The flagellated alga Euglena gracilis exhibits photoperiodism, with a long-day response in cell reproduction. The underlying clock is a circadian rhythm with photoinductive capability, peaking at subjective dusk and occurring at the 26th hour in continuous darkness (DD) when transferred from continuous light (LL); it regulates photoinduction, a high-irradiance response (HIR), of a dark-capability of progressing through cell division. We derived the action spectra by irradiating E. gracilis with monochromatic light for 3h at around the 26th hour; the action maxima occurred at 380, 450-460, 480, 610, 640, 660, 680, and 740nm. Except for the maximum at 450-460nm, which was always a major maximum, the maxima greatly depended on the red (R)/far-red (FR) ratio of the prior LL. The high R/FR ratio resulted in a dominant major peak at 640nm and minor peaks at 480 and 680nm, whereas the low ratio resulted in dominant major peaks at 610 and 740nm and minor peaks at 380 and 660nm; the critical fluence was minimally about 60mmolm(-2). These HIRs resulted from the accumulation of corresponding low-fluence responses (LFRs) because we found that repetition of a 3-min light/dark cycle, with critical fluences of 1mmolm(-2), lasting for 3h resulted in the same photoinduction as the continuous 3-h irradiation. Moreover, these LFRs expressed photoreversibility. Thus, photoperiodic photoinduction involves Euglena-phytochrome (640 and 740nm) and blue photoreceptor (460nm). Although 380, 480, 610, 660, and 680nm may also represent Euglena-phytochrome, a definite conclusion awaits further study.
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Affiliation(s)
- Aoen Bolige
- Laboratory of Biological Rhythms, Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080-8555, Japan
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Kiyota M, Numayama N, Goto K. Circadian rhythms of the l-ascorbic acid level in Euglena and spinach. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2006; 84:197-203. [PMID: 16679025 DOI: 10.1016/j.jphotobiol.2006.03.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Revised: 03/17/2006] [Accepted: 03/17/2006] [Indexed: 10/24/2022]
Abstract
Plant defenses against photo-oxidative stress have been studied almost exclusively with respect to stress responses, and little is known about how non-enzymic antioxidants change under constant conditions without a time cue or an environmental stress. Here, we show that, in both the flagellated alga Euglena gracilis Z and the angiosperm Spinacia oleracea L., the potent antioxidant L-ascorbic acid (Asc) displays a circadian rhythm with a maximum at subjective midday, a physiological state reflecting that attained at noon under daily light/dark cycles. Thus, photosynthetic organisms can maximize antioxidant levels in anticipation of midday, when photo-oxidative stress is most severe. These results may partly explain the in-phase circadian UV-C resistance rhythm recently identified in the alga. However, the Asc, but not the resistance, rhythm wanes in continuous darkness. This suggests the presence of persistent circadian rhythms in the levels of other antioxidants in continuous darkness, which may account for the UV-C resistance rhythm.
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Affiliation(s)
- Maki Kiyota
- Department of Food Science and Nutrition, Sagami Women's University, Sagamihara 228-8533, Japan
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20
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Bolige A, Kiyota M, Goto K. Circadian rhythms of resistance to UV-C and UV-B radiation in Euglena as related to ‘escape from light’ and ‘resistance to light’. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2005; 81:43-54. [PMID: 16111890 DOI: 10.1016/j.jphotobiol.2005.06.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2005] [Revised: 05/18/2005] [Accepted: 06/12/2005] [Indexed: 11/24/2022]
Abstract
Radiation-induced stress, either from visible or UV light, is strongest at midday. We found that, in the absence of stress or time cues, Euglena gracilis Z was the most resistant to UV-C and UV-B at subjective midday, whether judged from immediate or reproductive survival. The circadian UV-resistance rhythms were free-running in stationary cultures under 1-h light/1-h dark cycles or continuous darkness, indicating that cell-cycle dependent DNA susceptibility to UV was not involved. We moreover examined what was the primary cause of the circadian UV resistance, estimated as the immediate cell survival. The half-maximal lethal dose (LD(50)) of UV-C at subjective midday (the most resistant phase) was 156 J/m(2), which is approximately 3-fold that at subjective midnight. The same was true for UV-B, except the LD(50) was approximately 13-fold that of UV-C. Temperature during UV irradiation had little effect, indicating that survival was not mediated via enzymatic reactions. Non-enzymatic antioxidants were added 5 min before UV irradiation. Dimethylsulfoxide (a hydroxyl radical scavenger) increased survival after UV-B, but had little effect after UV-C; conversely, sodium ascorbate increased survival after UV-C, but not after UV-B. These findings suggest that circadian rhythms of resistance to UVs involve a common mechanism for maximizing non-enzymatic antioxidative capacity at subjective midday, but the specific antioxidants differ.
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Affiliation(s)
- Aoen Bolige
- Laboratory of Biological Rhythms, Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080-8555, Japan
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21
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Bolige A, Hagiwara SY, Zhang Y, Goto K. Circadian G2 Arrest as Related to Circadian Gating of Cell Population Growth in Euglena. ACTA ACUST UNITED AC 2005; 46:931-6. [PMID: 15821024 DOI: 10.1093/pcp/pci100] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Cell population growth is gated to occur in particular circadian phases, which has been known for over four decades in various organisms including cyanobacteria and human. However, little is known as to which cell cycle phases from G1 to M are primarily regulated by the circadian rhythm or when in a circadian cycle this primary regulation takes place. We report here that in the flagellate alga Euglena gracilis grown photoautotrophically, the circadian rhythm primarily prevented developmentally matured G2 cells from progressing to mitosis, such that cell population growth occurred only during subjective night. In addition, we found that the circadian rhythm also arrests G1-to-S and S-to-G2 transitions at particular circadian phases.
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Affiliation(s)
- Aoen Bolige
- Laboratory of Biological Rhythms, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, 080-8555 Japan
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22
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Hagiwara SY, Bolige A, Zhang Y, Takahashi M, Yamagishi A, Goto K. Circadian gating of photoinduction of commitment to cell-cycle transitions in relation to photoperiodic control of cell reproduction in Euglena. Photochem Photobiol 2002; 76:105-15. [PMID: 12126300 DOI: 10.1562/0031-8655(2002)076<0105:cgopoc>2.0.co;2] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A novel type of circadian and photoperiodic control of the cell division cycle was found in photoautotrophic Euglena gracilis. When algae entrained to 24 h light-dark (LD) cycles (14 h L) were transferred to continuous darkness (DD) at the eighth hour of the final LD photoperiod, cell-cycle transition was arrested in phase G1, S or G2. The subsequent exposure of these dark-arrested cells to a 6 h light-break allowed the dark-arrested cells to undergo cell-cycle progression in DD, in a manner dependent on the circadian phase; maximum photoinduction occurred around dusk. Inhibitor experiments suggested that the photoinduced commitment of G2 cells to cell division required light for a signal originating in noncyclic photosynthetic electron transport (PET), particularly cytochrome b6-f but not for the metabolic energy required by the process. The fact that the circadian rhythm of photoinduction ran out-of-phase from that of noncyclic PET signaling suggests that the site of regulation by the former rhythm is downstream of noncyclic PET. The occurrence of maximum photoinduction around dusk suggests that the 'external coincidence' model of photoperiodic induction describes the activation of the photoinductive phase. Further evidence supporting this hypothesis is the relationship between cell reproduction and day length; the resulting sigmoidal curve indicates a combined effect of photosynthesizing period and circadian stimulation around dusk. Circadian control is shown to be an integral part of the mechanism for 24 h LD cycle-induced synchronous cell division.
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Affiliation(s)
- Shin-ya Hagiwara
- Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo, Japan
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Affiliation(s)
- U Schibler
- Department of Molecular Biology, Sciences II, University of Geneva, CH-1211 Geneva 4, Switzerland.
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Chapter 11 Phototaxis of Euglena gracilis—flavins and pterins. COMPREHENSIVE SERIES IN PHOTOSCIENCES 2001. [DOI: 10.1016/s1568-461x(01)80015-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Abstract
There is reason to believe that resting free calcium concentration [Ca2+]i in neurons in the suprachiasmatic nucleus (SCN) may vary with the circadian cycle. In order to start to examine this hypothesis, optical techniques were utilized to estimate resting Ca2+ levels in SCN cells in a rat brain slice preparation. [Ca2+]i measured from the soma was significantly higher in the day than in the night. Animals from a reversed light-dark cycle were used to confirm that the phase of the rhythm was determined by the prior light-dark cycle. The rhythm in Ca2+ levels continued to be expressed in tissue collected from animals maintained in constant darkness, thus confirming the endogenous nature of this variation. Interestingly, the rhythm in Ca2+ levels was not observed when animals were housed in constant light. Finally, the rhythm in Ca2+ levels was prevented when slices were exposed to tetrodotoxin (TTX), a blocker of voltage-sensitive sodium channels. Similar results were obtained with the voltage-sensitive Ca2+ channel blocker methoxyverapamil. These observations suggest a critical role for membrane events in driving the observed rhythm in Ca2+. Conceptually, this rhythm can be thought of as an output of the circadian oscillator. Because [Ca2+]i is known to play a critical role in many cellular processes, the presence of this rhythm is likely to have many implications for the cell biology of SCN neurons.
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Affiliation(s)
- C S Colwell
- Mental Retardation Research Center, Department of Psychiatry and Biobehavioural Sciences, University of California-Los Angeles, 760 Westwood Plaza, Los Angeles, CA 90024-1759, USA.
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26
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Lebert M, Porst M, Hader DP. Circadian rhythm of gravitaxis in Euglena gracilis. JOURNAL OF PLANT PHYSIOLOGY 1999; 155:344-349. [PMID: 11542916 DOI: 10.1016/s0176-1617(99)80115-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Euglena gracilis, a unicellular, photosynthetic flagellate is a model system for environmentally controlled behavioral reactions. One pronounced reaction is the orientation with respect to gravity. In synchronized cultures with no cell growth a distinct circadian rhythm of negative gravitactic orientation could be observed. The main maximum of sensitivity was detected 5 h after the beginning of the subjective day, the main minimum 5 h before the beginning of the subjective day. Transferring synchronized cultures to continuous light resulted in an almost instantaneous loss of rhythmicity. In contrast, after transfer to permanent darkness cells exhibited a circadian rhythm with a progressive shortening of the period for more than 5 days. These findings are in contrast to the circadian rhythm of phototaxis in Euglena, where a free-running period of 24 h was observed. Parallel measurements of negative gravitactic orientation, velocity, cell shape as well as cAMP concentration in synchronized cultures revealed a circadian rhythm of all reactions. The results are discussed with regard to the possible role of cell shape and cAMP in gravitactic orientation.
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Affiliation(s)
- M Lebert
- Friedrich-Alexander-Universitat, Institut fur Botanik und Pharmazeutische Biologie, Erlangen
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27
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Gómez LA, Moysset L, Simón E. Effects of Calmodulin Inhibitors and Blue Light on Rhythmic Movement of Robinia pseudoacacia Leaflets. Photochem Photobiol 1999. [DOI: 10.1111/j.1751-1097.1999.tb03353.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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28
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Katagiri S, Onai K, Nakashima H. Spermidine determines the sensitivity to the calmodulin antagonist, chlorpromazine, for the circadian conidiation rhythm but not for the mycelial growth in Neurospora crassa. J Biol Rhythms 1998; 13:452-60. [PMID: 9850006 DOI: 10.1177/074873098129000282] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The gene that suppresses the phenotype of the cpz-2 mutation, which results in changing the sensitivity to chlorpromazine in relation to mycelial growth and circadian rhythms, was cloned in Neurospora crassa. This gene is not the cpz-2 gene itself but rather is identical to the spe-3 gene that encodes spermidine synthase in Neurospora. The intracellular content of spermidine was lowered in the cpz-2 strain compared to that of the wild-type strain. By integration of the spe-3 gene or by the addition of spermidine into culture medium, the temperature sensitivity of mycelial growth was lost and the conidiation rhythm became sensitive to chlorpromazine in the cpz-2 strain, as was observed in the wild-type strain, but the hypersensitivity of mycelial growth on chlorpromazine in the cpz-2 strain was not affected. Therefore, it appears that spermidine determines only the sensitivity of the conidiation rhythm to chlorpromazine.
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Affiliation(s)
- S Katagiri
- Department of Biology, Faculty of Science, Okayama University, Japan
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29
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Abstract
The time structure of a biological system is at least as intricate as its spatial structure. Whereas we have detailed information about the latter, our understanding of the former is still rudimentary. As techniques for monitoring intracellular processes continuously in single cells become more refined, it becomes increasingly evident that periodic behaviour abounds in all time domains. Circadian timekeeping dominates in natural environments. Here the free-running period is about 24 h. Circadian rhythms in eukaryotes and prokaryotes allow predictive matching of intracellular states with environmental changes during the daily cycles. Unicellular organisms provide excellent systems for the study of these phenomena, which pervade all higher life forms. Intracellular timekeeping is essential. The presence of a temperature-compensated oscillator provides such a timer. The coupled outputs (epigenetic oscillations) of this ultradian clock constitute a special class of ultradian rhythm. These are undamped and endogenously driven by a device which shows biochemical properties characteristic of transcriptional and translational elements. Energy-yielding processes, protein turnover, motility and the timing of the cell-division cycle processes are all controlled by the ultradian clock. Different periods characterize different species, and this indicates a genetic determinant. Periods range from 30 min to 4 h. Mechanisms of clock control are being elucidated; it is becoming evident that many different control circuits can provide these functions.
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Affiliation(s)
- D Lloyd
- Microbiology Group (PABIO), University of Wales Cardiff, UK
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30
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Miwa I, Izumo T, Sonoda T. Cytoplasm rescues an arrhythmic mutant on the circadian rhythm of mating reactivity in Paramecium bursaria. J Eukaryot Microbiol 1996; 43:231-6. [PMID: 8640193 DOI: 10.1111/j.1550-7408.1996.tb01397.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Cells of an unusual Paramecium bursaria stock (Sj2) expressed rhythmic mating reactivity in a light/dark cycle (LD) and under continuous illumination (LL). When placed in continuous darkness (DD), did not show rhythmicity but rather demonstrated a continuous high mating reactivity. However, mating reactivity was reduced following exposure to a 6-h light pulse interrupting the DD, and then recovered to its former condition. Genetic analysis showed the arrhythmicity in DD to be a dominant character inherited in a Mendelian ratio. On the other hand, a clone (MC1w) that did not show the rhythmicity in either DD or LL was isolated from the parent stock Sj2w following a 5-h treatment with 2 micrograms/ml nitrosoguanidine (MNNG). The MC1w cells expressed weak rhythmicity in LD, but were insensitive to a 6-h light pulse in DD. The arrhythmicity in LL was inherited cytoplasmically. In addition to this, rhythmicity in LL could be recovered by injection of cytoplasm from the wild-type cell when the recipient cell was homozygous for the wild-type nuclear gene (+/+). The cytoplasmic components or factors are assumed to control the functional circadian system and genetically determine the rhythmicity of mating reactivity.
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Affiliation(s)
- I Miwa
- Biological Laboratory, College of General Education, Ibaraki University, Japan
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31
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Johnson CH, Knight MR, Kondo T, Masson P, Sedbrook J, Haley A, Trewavas A. Circadian oscillations of cytosolic and chloroplastic free calcium in plants. Science 1995; 269:1863-5. [PMID: 7569925 DOI: 10.1126/science.7569925] [Citation(s) in RCA: 220] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Tobacco and Arabidopsis plants, expressing a transgene for the calcium-sensitive luminescent protein apoaequorin, revealed circadian oscillations in free cytosolic calcium that can be phase-shifted by light-dark signals. When apoaequorin was targeted to the chloroplast, circadian chloroplast calcium rhythms were likewise observed after transfer of the seedlings to constant darkness. Circadian oscillations in free calcium concentrations can be expected to control many calcium-dependent enzymes and processes accounting for circadian outputs. Regulation of calcium flux is therefore fundamental to the organization of circadian systems.
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Affiliation(s)
- C H Johnson
- Department of Biology, Vanderbilt University, Nashville, TN 37235, USA
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32
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Gómez LA, Simón E. CIRCADIAN RHYTHM OF Robinia pseudoacacia LEAFLET MOVEMENTS: ROLE OF CALCIUM AND PHYTOCHROME. Photochem Photobiol 1995. [DOI: 10.1111/j.1751-1097.1995.tb03963.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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33
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Khalsa SB, Ralph MR, Block GD. The role of extracellular calcium in generating and in phase-shifting the Bulla ocular circadian rhythm. J Biol Rhythms 1993; 8:125-39. [PMID: 8369549 DOI: 10.1177/074873049300800203] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Since extracellular calcium is known to be involved in the entrainment of the circadian pacemaker in the retina of Bulla gouldiana, we have assessed the requirement for extracellular calcium in the generation of the circadian rhythm. To enable us to assay the state of the pacemaker during low-calcium treatment, which often obscures rhythmicity, long-duration pulses of low-calcium artificial seawater (no added calcium, 10 mM EGTA, calculated calcium concentration = 4.5 x 10(-10) M) were applied, and the phase of the subsequent rhythm was measured. Pulse treatments started at zeitgeber time (ZT) 6, and durations ranged from 4 to 72 hr. Although no phase shifts followed pulses ending before the next projected dawn (ZT 24), phase delays of up to 4 hr followed pulses ending after projected dawn, and delays of up to 8 hr followed pulses spanning two dawns. Some activity records exhibited unequivocal circadian rhythmicity during the long low-calcium treatments, with phases and periods similar to untreated control eye records; this finding suggests that the phase delays observed following long low-calcium pulses are attributable to the pulsatile nature of the treatment. These data suggest that extracellular calcium is not an essential requirement for the pacemaker in generating the circadian rhythm.
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Affiliation(s)
- S B Khalsa
- NSF Center for Biological Timing, Department of Biology, Charlottesville, Virginia 22901
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34
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Block GD, Khalsa SB, McMahon DG, Michel S, Guesz M. Biological clocks in the retina: cellular mechanisms of biological timekeeping. INTERNATIONAL REVIEW OF CYTOLOGY 1993; 146:83-144. [PMID: 8360015 DOI: 10.1016/s0074-7696(08)60381-2] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- G D Block
- Department of Biology, University of Virginia, Charlottesville 22901
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35
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Edmunds LN, Carré IA, Tamponnet C, Tong J. The role of ions and second messengers in circadian clock function. Chronobiol Int 1992; 9:180-200. [PMID: 1319285 DOI: 10.3109/07420529209064529] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The fact that single cells can exhibit circadian rhythmicity simultaneously in quite different processes, such as those of photosynthesis, bioluminescence, and cell division, suggests that membrane-bound compartmentalization is important for temporal organization. Since these rhythms, as well as others, are known to be affected by changes in the ionic environment and are probably membrane-bound systems, it is not surprising that transmembrane ion transport or flux has been proposed to be a key feature of the underlying circadian oscillator(s). Likewise, signal transduction along the entrainment pathway leading to the clock, among the elements, or "gears," of the timing loop itself, and within the output pathway between the oscillator and its "hands" likely is mediated by ions and second messengers. In this overview, we examine the theoretical and experimental evidence supporting the possible roles of intracellular free calcium and cyclic AMP in these capacities, particularly in view of the fact that oscillations in the concentrations of both species have been proposed to form the basis of pacemaker activity and other biological rhythms.
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Affiliation(s)
- L N Edmunds
- Department of Anatomical Sciences, State University of New York, Stony Brook 11794
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36
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Abstract
Senescence is a process which, until quite recently, has been the subject of little scientific investigation. Even the word "senescence" is difficult to define, and complex methodological pitfalls have impeded progress. In the past few years, there have been exciting advances in understanding the physiological, cell biological, biochemical, and molecular biological nature of senescence. Changes in membrane function, protein synthesis, DNA structure (including glycosylation, altered tertiary structure, free-radical effects, and loss of telomeric DNA), and changes in gene regulation with age are reviewed. Recent work on changes in responses to transcriptional regulatory proteins and cellular senescence factors, some of which have been identified, is particularly promising and leads to the conclusion that senescence, at least in part, is a programmed process. Despite these advances, the fundamental cause of senescence remains elusive but might, as in the case of other biological processes which are phylogenetically widespread, turn out to be quite simple, and perhaps, even modifiable.
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Affiliation(s)
- J L Kirkland
- Institute of Medical Science, University of Toronto, Ontario, Canada
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37
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Scheibel LW. Role of calcium/calmodulin-mediated processes in protozoa. INTERNATIONAL REVIEW OF CYTOLOGY 1992; 134:165-242. [PMID: 1582773 DOI: 10.1016/s0074-7696(08)62029-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- L W Scheibel
- Department of Preventive Medicine, Uniformed Services University of the Health Sciences School of Medicine, Bethesda, Maryland 20814
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38
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Schoffeniels E. [Comparative biochemical systems]. ARCHIVES INTERNATIONALES DE PHYSIOLOGIE, DE BIOCHIMIE ET DE BIOPHYSIQUE 1991; 99:1-46. [PMID: 1713481 DOI: 10.3109/13813459109145902] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- E Schoffeniels
- Institut Léon Fredericq, Laboratoire de Biochimie générale et comparée, Université de Liège
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39
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Abstract
This article reviews the evidence that living systems at all levels, including cells, organs, organisms, groups, organizations, communities, societies, and supranational systems, have an information-processing system, the timer. The timer consists of one or more oscillators known as clocks or pacemakers, the phase of which can be reset. They measure duration or order in time or underlie rhythms of various sorts. The timer subsystem synchronizes internal processes of the system and coordinates the system with its environment. By 1965, 19 matter-energy and information processing subsystems were identified in living systems theory. Based on scientific evidence accumulated particularly in recent years, the timer is now recognized as an information processing subsystem, the 20th subsystem, which carries out an essential life process.
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40
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41
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Laval-Martin DL, Carré IA, Barbera SJ, Edmunds LN. Rhythmic changes in the activities of NAD kinase and NADP phosphatase in the achlorophyllous ZC mutant of Euglena gracilis Klebs (strain Z). Arch Biochem Biophys 1990; 276:433-41. [PMID: 2154948 DOI: 10.1016/0003-9861(90)90742-h] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
NAD kinase and NADP phosphatase activities were detected in the supernatant and the pellet fractions prepared by sonication and centrifugation of the achlorophyllous ZC mutant of the phytoflagellate Euglena gracilis. A detailed study of substrate concentration-velocity curves enabled us to define the saturating substrate concentrations that were used in the enzyme assays. An analysis of the reproducibility of the entire assay procedure indicated that the pooled standard error was about 14%. We report circadian variations in the activities of NAD kinase and NADP phosphatase in the soluble and membrane-bound fractions of both synchronously dividing and nondividing cultures maintained in constant darkness. Bimodal circadian rhythms in total NADP phosphatase activity were found in dividing cells (peaks at circadian times [CT] 00 and 12). The peak observed at CT 00-03 disappeared when the cells had ceased dividing, a result that suggests that it might be regulated by the cell division cycle. NAD kinase activity displayed unimodal circadian rhythms (peak at CT 12) in dividing cells, which persisted with the same phase after the culture entered the stationary phase of growth. Results are discussed with reference to a model (K. Goto, D. L. Laval-Martin, and L. N. Edmunds, Jr., 1985, Science 228, 1284-1288) in which we have proposed that the Ca2(+)-transport system, Ca2+, calmodulin, NAD kinase, and NADP phosphatase could represent clock "gears" that might constitute a self-sustained circadian oscillating loop.
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Affiliation(s)
- D L Laval-Martin
- Department of Anatomical Sciences, State University of New York, Stony Brook 11794
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42
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43
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Rensing L, Hardeland R. The cellular mechanism of circadian rhythms--a view on evidence, hypotheses and problems. Chronobiol Int 1990; 7:353-70. [PMID: 2097068 DOI: 10.3109/07420529009059146] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A stable period length is a characteristic property of circadian oscillations. The question about whether higher frequency oscillators (0.5-8 hr) contribute to or establish the stable circadian periodicity cannot be answered at present. A sequential coupling of quantal subcycles appears possible on the basis of known "ultradian" oscillations. There is, however, no supporting evidence for such a concept. Phase response curves of the circadian clock derived from various perturbing pulses allow qualitative conclusions concerning the perturbed clock process. Deductions from computer simulations also allow conclusions about the phase of this oscillatory process. The distinction between processes (a) essential to the clock mechanism, (b) maintaining and controlling the clock (inputs) and (c) depending on the clock (outputs) on the basis of "oscillatory" and "change of psi or tau after perturbation" seems to be useful but not stringent. Protein synthesis may be an essential or input process. Oscillatory changes of this process may be due to periodic translational control or RNA-supply. Circadian changes in protein concentration and/or activity may depend on periodic synthesis, proteolysis, covalent modifications or aggregations. Specific essential proteins have not been identified conclusively. The large overlap between the group of agents and treatments that phase shift the clock and the group that induces stress proteins suggest that the latter may play a role in the controlling (input) or essential domain. The role of membranes in the clock mechanism is not clear: concepts assuming an essential function are based on circumstantial evidence. The membrane potential as well as Ca2+ may be involved in either input or essential function. Ca(2+)-calmodulin may also be important as concluded from inhibitor experiments. It is tempting to assume that a calmodulin-dependent kinase is part of a periodic protein phosphorylation process, yet it is not clear whether the periodic protein phosphorylation that has been observed is essential or is just another output process.
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Affiliation(s)
- L Rensing
- Biology Department, University of Bremen, Germany
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Lakin-Thomas PL, Coté GG, Brody S. Circadian rhythms in Neurospora crassa: biochemistry and genetics. Crit Rev Microbiol 1990; 17:365-416. [PMID: 2147375 DOI: 10.3109/10408419009114762] [Citation(s) in RCA: 115] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Techel D, Gebauer G, Kohler W, Braumann T, Jastorff B, Rensing L. On the role of Ca2(+)-calmodulin-dependent and cAMP-dependent protein phosphorylation in the circadian rhythm of Neurospora crassa. J Comp Physiol B 1990; 159:695-706. [PMID: 2159489 DOI: 10.1007/bf00691715] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Pulses of some Ca2+ channel blockers (dantrolene, Co2+, nifedipine) and calmodulin inhibitors (chlorpromazine) lead to medium (maximally 5-9 h) phase shifts of the circadian conidiation rhythm of Neurospora crassa. Pulses of high Ca2+, or of low Ca2+, a Ca2+ ionophore (A23187) together with Ca2+, and other Ca2+ channel blockers (La3+, diltiazem), however, caused only minor phase shifts. The effect of these substances (A 23187) and of different temperatures on the Ca2+ release from isolated vacuoles was analyzed by using the fluorescent dye Fura-2. A 23187 and higher temperatures increased the release drastically, whereas dantrolene decreased the permeation of Ca2+ (Cornelius et al., 1989). Pulses of 8-PCTP-cAMP, IBMX and of the cAMP antagonist RP-cAMPS, also caused medium (maximally 6-9 h) phase shifts of the conidiation rhythm. The phase response curve of the agonist was almost 180 degrees out of phase with the antagonist PRC. In spite of some variability in the PRCs of these series of experiments all showed maximal shifts during ct 0-12. The variability of the response may be due to circadian changes in the activity of phosphodiesterases: After adding cAMP to mycelial extracts HPLC analysis of cAMP metabolites showed significant differences during a circadian period with a maximum at ct 0. Protein phosphorylation was tested mainly in an in vitro phosphorylation system (with 35S-thio gamma-ATP). The results showed circadian rhythmic changes predominantly in proteins of 47/48 kDa. Substances and treatments causing phase-shifts of the conidiation rhythm also caused changes in the phosphorylation of these proteins: an increase was observed when Ca2+ or cAMP were added, whereas a decrease occurred upon addition of a calmodulin inhibitor (TFP) or pretreatment of the mycelia with higher (42 degrees C) temperatures. Altogether, the results indicate that Ca2(+)-calmodulin-dependent and cAMP-dependent processes play an important, but perhaps not essential, role in the clock mechanism of Neurospora. Ca2+ calmodulin and the phosphorylation state of the 47/48-kDa proteins may have controlling or essential functions for this mechanism.
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Affiliation(s)
- D Techel
- Department of Biology, University of Bremen, Federal Republic of Germany
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Entrainment and phase shifting of the circadian rhythm of cell division by light in cultures of the achlorophyllous ZC mutant ofEuglena gracilis. Curr Microbiol 1989. [DOI: 10.1007/bf01570166] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Vanden Driessche T. The molecular mechanism of circadian rhythms. ARCHIVES INTERNATIONALES DE PHYSIOLOGIE ET DE BIOCHIMIE 1989; 97:1-11. [PMID: 2475080 DOI: 10.3109/13813458909075041] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The endogenous and ubiquitous circadian rhythms (CR) are not understood in molecular terms, in spite of recent interesting advances. They concern, on one hand, protein synthesis, of which a small fraction--possibly a single protein--, formed on cytosolic ribosomes, may be required on each 24 h cycle. On the other hand, the per gene, involved in the control of CR in drosophila has been found to direct the synthesis of 2 (or 3) proteoglycans. Several models have been put forward in order to explain CR generation. Considering the complexity of the cell's organization and the occurrence of partial arrhythmicity, CR generation might result from the integration of a few physiological and metabolic pathways normally involving at least one feed-back loop. Sequentiality would be inherent to the kinetics of both the metabolic pathways and translocators located in the membranes of the various compartments; as a consequence, the peaks of the oscillatory activities would be positioned at particular phase points relative to others. Proteoglycans (or other proteins modified post-transcriptionally) could be involved in the operation of rhythms in controlling not only some plasmalemma (as proposed by Yu et al., 1987) but also intracellular membranes. Finally, reversible enzyme modification occurring on each 24 h cycle could be critically important in circadian rhythms generation.
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Affiliation(s)
- T Vanden Driessche
- Département de Biologie moléculaire, Université libre de Bruxelles, Rhode-Saint Genèse
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Khalsa SB, Block GD. Phase-shifts of the Bulla ocular circadian pacemaker in the presence of calmodulin antagonists. Life Sci 1988; 43:1551-6. [PMID: 3193847 DOI: 10.1016/0024-3205(88)90404-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Previous work has shown that light-induced phase shifts of the Bulla ocular circadian pacemaker require extracellular calcium, suggesting the possibility that the action of calcium as a second messenger via calmodulin is an element in the phase shifting mechanism. The calmodulin antagonists calmidazolium, trifluoperazine (TFP) and W7 were applied with phase shifting light pulses. Light phase shifts were not blocked by calmidazolium or TFP, suggesting that calmodulin does not mediate light-induced phase shifts. Period changes were observed with treatments of both TFP and W7, but not with calmidazolium and are probably not calmodulin-mediated.
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Affiliation(s)
- S B Khalsa
- Department of Biology, University of Virginia, Charlottesville 22901
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Kippert F. Endocytobiotic coordination, intracellular calcium signaling, and the origin of endogenous rhythms. Ann N Y Acad Sci 1987; 503:476-95. [PMID: 3304083 DOI: 10.1111/j.1749-6632.1987.tb40631.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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50
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Edmunds LN, Laval-Martin DL, Goto K. Cell division cycles and circadian clocks. Modeling a metabolic oscillator in the algal flagellate Euglena. Ann N Y Acad Sci 1987; 503:459-75. [PMID: 3304082 DOI: 10.1111/j.1749-6632.1987.tb40630.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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