Weak radiofrequency fields affect the insect circadian clock

It is known that the circadian clock in Drosophila can be sensitive to static magnetic fields (MFs). Man-made radiofrequency (RF) electromagnetic fields have been shown to have effects on animal orientation responses at remarkably weak intensities in the nanotesla range. Here, we tested if weak broadband RF fields also affect the circadian rhythm of the German cockroach ( Blatella germanica ). We observed that static MFs slow down the cockroach clock rhythm under dim UV light, consistent with results on the Drosophila circadian clock. Remarkably, 300 times weaker RF fields likewise slowed down the cockroach clock in a near-zero static magnetic field. This demonstrates that the internal clock of organisms can be sensitive to weak RF fields, consequently opening the possibility of an influence of man-made RF fields on many clock-dependent events in living systems.

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PER2 Circadian Oscillation Sensitizes Esophageal Cancer Cells to Chemotherapy

Biology ◽

10.3390/biology10040266 ◽

2021 ◽

Vol 10 (4) ◽

pp. 266

Author(s):

Juan Alfonso Redondo ◽

Romain Bibes ◽

Alizée Vercauteren Drubbel ◽

Benjamin Dassy ◽

Xavier Bisteau ◽

...

Keyword(s):

Esophageal Cancer ◽

Circadian Rhythm ◽

Survival Rate ◽

Circadian Clock ◽

Cancer Cells ◽

Molecular Mechanisms ◽

Human Cancer ◽

Response To Therapy ◽

Circadian Oscillation ◽

Resistance To Therapy

Esophageal squamous cell carcinoma (eSCC) accounts for more than 85% cases of esophageal cancer worldwide and the 5-year survival rate associated with metastatic eSCC is poor. This low survival rate is the consequence of a complex mechanism of resistance to therapy and tumor relapse. To effectively reduce the mortality rate of this disease, we need to better understand the molecular mechanisms underlying the development of resistance to therapy and translate that knowledge into novel approaches for cancer treatment. The circadian clock orchestrates several physiological processes through the establishment and synchronization of circadian rhythms. Since cancer cells need to fuel rapid proliferation and increased metabolic demands, the escape from circadian rhythm is relevant in tumorigenesis. Although clock related genes may be globally repressed in human eSCC samples, PER2 expression still oscillates in some human eSCC cell lines. However, the consequences of this circadian rhythm are still unclear. In the present study, we confirm that PER2 oscillations still occur in human cancer cells in vitro in spite of a deregulated circadian clock gene expression. Profiling of eSCC cells by RNAseq reveals that when PER2 expression is low, several transcripts related to apoptosis are upregulated. Consistently, treating eSCC cells with cisplatin when PER2 expression is low enhances DNA damage and leads to a higher apoptosis rate. Interestingly, this process is conserved in a mouse model of chemically-induced eSCC ex vivo. These results therefore suggest that response to therapy might be enhanced in esophageal cancers using chronotherapy.

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Circadian Rhythm: Potential Therapeutic Target for Atherosclerosis and Thrombosis

International Journal of Molecular Sciences ◽

10.3390/ijms22020676 ◽

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.

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Effect of a static magnetic field onEscherichia coliadhesion and orientation

Canadian Journal of Microbiology ◽

10.1139/cjm-2015-0839 ◽

2016 ◽

Vol 62 (11) ◽

pp. 944-952 ◽

Cited By ~ 1

Author(s):

Lotfi Mhamdi ◽

Nejib Mhamdi ◽

Naceur Mhamdi ◽

Philippe Lejeune ◽

Nicole Jaffrezic ◽

...

Keyword(s):

Magnetic Field ◽

Tin Oxide ◽

Indium Tin Oxide ◽

Bacterial Adhesion ◽

Parallel Magnetic Field ◽

Field Orientation ◽

Static Magnetic Fields ◽

Preliminary Study ◽

The Difference ◽

The Magnetic Field

This preliminary study focused on the effect of exposure to 0.5 T static magnetic fields on Escherichia coli adhesion and orientation. We investigated the difference in bacterial adhesion on the surface of glass and indium tin oxide-coated glass when exposed to a magnetic field either perpendicular or parallel to the adhesion surface (vectors of magnetic induction are perpendicular or parallel to the adhesion surface, respectively). Control cultures were simultaneously grown under identical conditions but without exposure to the magnetic field. We observed a decrease in cell adhesion after exposure to the magnetic field. Orientation of bacteria cells was affected after exposure to a parallel magnetic field. On the other hand, no effect on the orientation of bacteria cells was observed after exposure to a perpendicular magnetic field.

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Biodegradable Magnetic Nanocomposite Spheres Fabrication by O∕O Emulsion∕Solvent Evaporation Technique for Drug Delivery Purposes

Journal of Medical Devices ◽

10.1115/1.2932349 ◽

2008 ◽

Vol 2 (2) ◽

Author(s):

R. Asmatulu ◽

A. Fakhari

Keyword(s):

Magnetic Field ◽

Drug Delivery ◽

Magnetic Nanoparticles ◽

Uv Light ◽

Solvent Evaporation ◽

Ferrous Chloride ◽

Strong Base ◽

Nanocomposite Particles ◽

Pump Speed ◽

Evaporation Technique

Drug targeting systems are important research areas for many diseases treatments (e.g., cancer, nerve damage, heart and artery, diabetic, eye and other medical treatments). Currently, magnetic field, electric field, ultrasound, temperature, UV light and∕or mechanical force systems are considered more for research and development. Magnetic targeted drug delivery system is usually preferred because targeted systems improve the therapeutic index of drug molecules by minimizing the toxic side effects on healthy cells and tissues. In this study, magnetic nanoparticles (∼10nm) were prepared by a chemical coprecipitation of ferric and ferrous chloride salts in the presence of a strong base (ammonium hydroxide) and used for a drug delivery purposes. An oil-in-oil emulsion∕solvent evaporation technique was chosen for the synthesis of nanocomposite spheres. Percentages of magnetic nanoparticles (%5, %10, %20 and%30) and poly(D,L-lactide-co-glycolide) were combined together to produce nanocomposite particles with diameters of 500nmto1.2micronmeter. The effect of particle concentrations on nanocomposite particle size and distribution and morphology were investigated by using scanning electron microscopy (SEM) and laser light scattering (LLS). Additionally, external magnetic fields with various magnet distance, magnetic field, pump speed and solid contents were applied to the nanocomposite particles in a liquid media to find out the effect of variables for the targeting of drug carrying nanocomposite spheres.

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PHOTOPRODUCTION OF DILATONS IN AN EXTERNAL MAGNETIC FIELD

Modern Physics Letters A ◽

10.1142/s0217732300000050 ◽

2000 ◽

Vol 15 (01) ◽

pp. 23-28 ◽

Cited By ~ 1

Author(s):

DANG VAN SOA ◽

HOANG NGOC LONG

Keyword(s):

Magnetic Field ◽

External Magnetic Field ◽

Cross Sections ◽

Differential Cross ◽

Numerical Evaluation ◽

Static Magnetic Fields ◽

Five Dimensions ◽

High Energies ◽

Klein Theory ◽

Kaluza Klein

An attempt is made to present some experimental predictions of the five dimensions Kaluza–Klein theory. The conversion of photons into dilatons in the static magnetic fields are considered in detail. The differential cross-sections are presented for the conversions in a magnetic field of the flat condensor and a magnetic field of the solenoid. A numerical evaluation shows that in the present technical scenario, the creation of dilatons at high energies may have the observable value.

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Novel static magnetic field effects on green chemistry biosynthesis of silver nanoparticles in Saccharomyces cerevisiae

Scientific Reports ◽

10.1038/s41598-021-99487-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ameni Kthiri ◽

Selma Hamimed ◽

Abdelhak Othmani ◽

Ahmed Landoulsi ◽

Siobhan O’Sullivan ◽

...

Keyword(s):

Magnetic Field ◽

Saccharomyces Cerevisiae ◽

Silver Nanoparticles ◽

Magnetic Fields ◽

Green Chemistry ◽

Static Magnetic Field ◽

Culture Medium ◽

Average Diameter ◽

Magnetic Field Effects ◽

Static Magnetic Fields

AbstractThe bacteriocidal properties of silver nanoparticles (AgNPs) depend on their average diameter (toxicity increases with decreasing diameter). In the present work, we describe novel green chemistry biosynthesis of AgNPs from AgNO3 added to cell-free culture medium of baker’s yeast, Saccharomyces cerevisiae, yielding nanoparticles in the range 11–25 nm. However, when yeast was grown in a moderate static magnetic field, AgNPs obtained from the resulting cell-free culture medium, were significantly smaller (2–12 nm) than those obtained without magnetic field. These latter nanoparticles were highly crystalline, stable and near-uniform shape. Furthermore, the antibacterial activity of AgNPs obtained from static magnetic fields were greater than those from control cultures. Static magnetic fields show a promising ability to generate biocidal nanoparticles via this novel green chemistry approach.

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MECHANISMS IN ENDOCRINOLOGY: A sense of time of the glucocorticoid circadian clock: from the ontogeny to the diagnosis of Cushing’s syndrome

Acta Endocrinologica ◽

10.1530/eje-18-0102 ◽

2018 ◽

Vol 179 (1) ◽

pp. R1-R18 ◽

Cited By ~ 6

Author(s):

Ayrton Custodio Moreira ◽

Sonir Rauber Antonini ◽

Margaret de Castro

Keyword(s):

Circadian Rhythm ◽

Circadian Clock ◽

Clock Genes ◽

Circadian Variation ◽

Circadian System ◽

Feedback Loops ◽

Adrenal Axis ◽

Sense Of Time ◽

Pituitary Adrenal Axis ◽

Hierarchical Manner

The circadian rhythm of glucocorticoids has long been recognised within the last 75 years. Since the beginning, researchers have sought to identify basic mechanisms underlying the origin and emergence of the corticosteroid circadian rhythmicity among mammals. Accordingly, Young, Hall and Rosbash, laureates of the 2017 Nobel Prize in Physiology or Medicine, as well as Takahashi’s group among others, have characterised the molecular cogwheels of the circadian system, describing interlocking transcription/translation feedback loops essential for normal circadian rhythms. Plasma glucocorticoid circadian variation depends on the expression of intrinsic clock genes within the anatomic components of the hypothalamic–pituitary–adrenal axis, which are organised in a hierarchical manner. This review presents a general overview of the glucocorticoid circadian clock mechanisms, highlighting the ontogeny of the pituitary–adrenal axis diurnal rhythmicity as well as the involvement of circadian rhythm abnormalities in the physiopathology and diagnosis of Cushing’s disease.

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Circadian Rhythm of Output from Neurones in the Eye of Aplysia: II. Effects of Cold Pulses on a Population of Coupled Oscillators

Journal of Experimental Biology ◽

10.1242/jeb.70.1.167 ◽

1977 ◽

Vol 70 (1) ◽

pp. 167-181

Author(s):

JACK A. BENSON ◽

JON W. JACKLET

Keyword(s):

Circadian Rhythm ◽

Circadian Clock ◽

Coupled Oscillators ◽

Phase Point ◽

Frequency Curve ◽

Phase Angle Difference ◽

Long Duration ◽

Large Phase ◽

East West ◽

Frequency Curves

1. The circadian clock that controls CAP frequency was stopped at or near its lowest phase point by long duration cold pulses of 6 °C. On return to normal recording temperature (15 °C), the rhythm was always reinitiated from this phase point. 2. Following long cold pulses, there was often a transient peak of CAP activity lasting 2-6 h. It is thought that this was an effect of rise in temperature after prolonged cooling and not an effect on the clock itself. 3. Twelve h cold pulses, spanning the rhythm peak, caused phase delays. 9 °C pulses caused small delays (e.g. 1.7 h) while large phase delays (e.g. 6.7 h) followed pulses of 5 °C. Some pulses at an intermediate temperature (8.5 °C) caused abnormal post-pulse cycles lasting several days, and resulting in very large phase delays (10–14 n). 4. The abnormal CAP frequency curves following 12 h cold pulses of 8.5 °C spanning the rhythm peak are interpreted as rhythm splits. It is postulated that part of the population of coupled oscillators comprising the circadian clock was slightly delayed by the cold pulse, while the other part was driven further towards the “stopped” state, thus producing a large phase angle difference between the two subpopulations. These drew one another back into phase during several cycles to reform a normal circadian rhythm. 5. It is hypothesized that the circadian oscillations of the two subpopulations did not sum to produce the observed CAP frequency curve; rather the level of CAP output was controlled by whichever subpopulation was discharging at the higher frequency. Note: Laboratory of Sensory Sciences, University of Hawaii at Manoa, 1993 East-West Road, Honolulu, Hawaii 96822, U.S.A.

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Circadian Rhythm of Output from Neurones in the Eye of Aplysia: III. Effects of Light on Clock and Receptor Output Measured in the Optic Nerve

Journal of Experimental Biology ◽

10.1242/jeb.70.1.183 ◽

1977 ◽

Vol 70 (1) ◽

pp. 183-194

Author(s):

JACK A. BENSON ◽

JON W. JACKLET

Keyword(s):

Circadian Rhythm ◽

Optic Nerve ◽

Circadian Clock ◽

Light Pulse ◽

Temperature Sensitivity ◽

Phase Point ◽

Light Onset ◽

Constant Illumination ◽

Light Pulses ◽

East West

1. The circadian rhythm of CAP frequency recorded from the optic nerve of isolated eyes at 15 °C was damped out by constant illumination (1100 lux) after several cycles of the rhythm. During illumination (LL) the rhythm was skewed with a rapid rising phase and slow falling phase, and the period was decreased by about 1 h. It is postulated that the circadian clock was stopped by LL at its lowest phase point, and that following cessation of LL, the rhythm was reinitiated from this phase point after a latency of 6-8 h. 2. For light pulses of 80 lux and 1100 lux, the photoresponse of the dark-adapted eye to 20 min light pulses applied beginning at 2 h intervals was not influenced by the circadian clock. At 5 lux there was a periodicity in the magnitude of the photoresponse, in phase with the circadian rhythm of spontaneous CAP production. 3. Small CAPs of non-circadian frequency were recorded together with normal CAPs in about 10% of records of output from isolated eyes. The cells producing the small CAPs had a different temperature sensitivity from those producing normal CAPs. The response of these cells to short light pulses consisted of a phasic burst of activity at light onset, followed by silence during the remainder of the short light pulse, and for 1 or 2 min following cessation of illumination. These small CAPs may be the activity either of H-type receptors or of secondary cells desynchronized from the major population. Note: Laboratory of Sensory Sciences, University of Hawaii at Manoa, 1993 East-West Road, Honolulu, Hawaii 96822, U.S.A.

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Abstract 3: Cellular Contributions of the Circadian Clock in Atherogenesis

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.37.suppl_1.3 ◽

2017 ◽

Vol 37 (suppl_1) ◽

Author(s):

Xueling Li ◽

Ling Ruan ◽

Austin Bentley ◽

Stephen Haigh ◽

Yuqing Huo ◽

...

Keyword(s):

Blood Pressure ◽

Endothelial Cells ◽

Circadian Rhythm ◽

Circadian Clock ◽

Cell Types ◽

No Production ◽

Light Cycle ◽

Lipid Uptake ◽

Enhanced Production ◽

The Impact

Atherosclerosis is a leading cause of death despite the improvements in lipid and blood pressure control. The circadian clock, a molecular network of genes and proteins that controls 24-hour timing, has emerged to have a surprising role in the control of metabolic and vascular function. Herein we examined the impact of circadian rhythm dysfunction in atherogenesis by implementation of vascular transplant and PCSK9 based approaches to induce accelerated lesion development in mice. We find that atherogenesis is exacerbated in Bmal1-KO aortic grafts immersed in the hypercholesterolemic milieu of ApoE -/- mice. To assess if atherosclerosis was ‘circadian rhythm dependent’ we subjected wild-type mice to a shortened light cycle (4L/4D) and induced atherosclerosis by intravenous injection of a human PCSK-9 adeno associated virus. Atherosclerosis in the jet-lagged PCSK-9 mice was robustly increased relative to the atherosclerosis observed in WT mice on a normal light cycle (12L/12D), providing further evidence that circadian rhythm and the circadian clock contribute to atherosclerosis. However, atherosclerosis is a complex disease that is the net result of interplay between intrinsic (vascular cells) and extrinsic mechanisms (metabolism, blood pressure, and hormones) and the importance of clock function in individual cell types is poorly understood. We found that deletion or silencing of key circadian transcription factors resulted in an enhanced inflammatory and pro-oxidant phenotype with diminished NO production and greater lipid uptake in both macrophages and endothelial cells. Loss of circadian function in smooth muscle cells similarly resulted in enhanced production of reactive oxygen species and greater cell proliferation. Surprising, the silencing of Bmal2 in endothelial cells resulted in greater lipid uptake in oxLDL treated HAEC as well as increased expression of markers of autophagy, suggesting that Bmal2 may orchestrate numerous output functions in different cell types. In conclusion, we find that the circadian clock and circadian rhythm have a profound impact on atherosclerosis, to influence vascular cell inflammatory and lipid uptake responses, and identify an unexpectedly prominent role for the side-partner of Bmal1, Bmal2.

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