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1.
Invest Ophthalmol Vis Sci ; 60(12): 3786-3793, 2019 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-31504080

RESUMO

Purpose: Light-emitting diodes that emit high-intensity blue light are associated with blue-light hazard. Here, we report that blue light disturbs circadian rhythms by interfering with the clock gene in the suprachiasmatic nucleus (SCN) and that suppression of blue light at night ameliorates metabolic abnormalities by controlling circadian rhythms. Methods: C57BL/6J mice were exposed to 10-lux light for 30 minutes at Zeitgeber time 14 for light pulse with blue light or blue-light cut light to induce phase shift of circadian rhythms. Phase shift, clock gene expression in SCN, and metabolic parameters were analyzed. In the clinical study, healthy participants wore blue-light shield eyewear for 2 to 3 hours before bed. Anthropometric data analyses, laboratory tests, and sleep quality questionnaires were performed before and after the study. Results: In mice, phase shift induced with a blue-light cut light pulse was significantly shorter than that induced with a white light pulse. The phase of Per2 expression in the SCN was also delayed after a white light pulse. Moreover, blood glucose levels 48 hours after the white light pulse were higher than those after the blue-cut light pulse. Irs2 expression in the liver was decreased with white light but significantly recovered with the blue-cut light pulse. In a clinical study, after 1 month of wearing blue-light shield eyeglasses, there were improvements in fasting plasma glucose levels, insulin resistance, and sleep quality. Conclusions: Our results suggest that suppression of blue light at night effectively maintains circadian rhythms and metabolism.


Assuntos
Glicemia/metabolismo , Ritmo Circadiano/efeitos da radiação , Luz , Metabolismo dos Lipídeos/fisiologia , Proteção Radiológica , Sono/fisiologia , Adulto , Animais , Antropometria , Proteínas CLOCK/genética , Regulação da Expressão Gênica/fisiologia , Humanos , Proteínas Substratos do Receptor de Insulina/metabolismo , Fígado/metabolismo , Masculino , Melatonina/urina , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Atividade Motora , Reação em Cadeia da Polimerase em Tempo Real , Núcleo Supraquiasmático/metabolismo , Inquéritos e Questionários
2.
Nature ; 574(7777): 254-258, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31534216

RESUMO

Group 3 innate lymphoid cells (ILC3s) are major regulators of inflammation, infection, microbiota composition and metabolism1. ILC3s and neuronal cells have been shown to interact at discrete mucosal locations to steer mucosal defence2,3. Nevertheless, it is unclear whether neuroimmune circuits operate at an organismal level, integrating extrinsic environmental signals to orchestrate ILC3 responses. Here we show that light-entrained and brain-tuned circadian circuits regulate enteric ILC3s, intestinal homeostasis, gut defence and host lipid metabolism in mice. We found that enteric ILC3s display circadian expression of clock genes and ILC3-related transcription factors. ILC3-autonomous ablation of the circadian regulator Arntl led to disrupted gut ILC3 homeostasis, impaired epithelial reactivity, a deregulated microbiome, increased susceptibility to bowel infection and disrupted lipid metabolism. Loss of ILC3-intrinsic Arntl shaped the gut 'postcode receptors' of ILC3s. Strikingly, light-dark cycles, feeding rhythms and microbial cues differentially regulated ILC3 clocks, with light signals being the major entraining cues of ILC3s. Accordingly, surgically or genetically induced deregulation of brain rhythmicity led to disrupted circadian ILC3 oscillations, a deregulated microbiome and altered lipid metabolism. Our work reveals a circadian circuitry that translates environmental light cues into enteric ILC3s, shaping intestinal health, metabolism and organismal homeostasis.


Assuntos
Encéfalo/efeitos da radiação , Ritmo Circadiano/efeitos da radiação , Homeostase/efeitos da radiação , Intestinos/imunologia , Intestinos/efeitos da radiação , Luz , Linfócitos/imunologia , Linfócitos/efeitos da radiação , Fatores de Transcrição ARNTL/deficiência , Fatores de Transcrição ARNTL/genética , Fatores de Transcrição ARNTL/metabolismo , Animais , Relógios Biológicos/genética , Relógios Biológicos/efeitos da radiação , Encéfalo/fisiologia , Ritmo Circadiano/genética , Ritmo Circadiano/imunologia , Ritmo Circadiano/fisiologia , Sinais (Psicologia) , Comportamento Alimentar/efeitos da radiação , Feminino , Microbioma Gastrointestinal/efeitos da radiação , Imunidade Inata/efeitos da radiação , Intestinos/citologia , Metabolismo dos Lipídeos , Linfócitos/metabolismo , Masculino , Camundongos , Fotoperíodo
3.
J Physiol Anthropol ; 38(1): 10, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31462321

RESUMO

BACKGROUND: Recently, more consideration is being given to the beneficial effects of lighting on the maintenance and promotion of the health and well-being of office occupants in built environments. A new lighting technology using Rayleigh scattering has made it possible to simulate a blue sky. However, to date, no studies have examined the possible beneficial effects of such artificial skylights. The aims of this study were to examine the non-visual effects of artificial skylights and conventional fluorescent lights in a simulated office environment and to clarify the feature effects of the artificial skylights. METHODS: Participants were 10 healthy male adults. Non-visual effects were evaluated based on brain arousal levels (α-wave ratio and contingent negative variation [CNV]), autonomic nervous activity (heart rate variability [HRV]), work performance, and subjective responses during daytime exposure to either an artificial skylight or fluorescent lights, as well as nocturnal melatonin secretion. RESULTS: Subjective evaluations of both room lighting-related "natural" and "attractive" items and the "connected to nature" item were significantly higher with the skylight than with the fluorescent lights. Cortical arousal levels obtained from the early component of the CNV amplitude were significantly lower with the skylight than with the fluorescent lights, whereas α-wave ratio and work performance were similar between the two light sources. The HRV evaluation showed that sympathetic nerve tone was lower and parasympathetic nerve tone was higher, both significantly, for the skylight than for the fluorescent lights during daytime. Nocturnal melatonin secretion was significantly greater before and during light exposure at night under the daytime skylight than under the fluorescent lights. CONCLUSIONS: Our results suggest that artificial skylights have some advantages over conventional fluorescent lights in maintaining ordinary work performance during daytime with less psychological and physiological stress. The findings also suggest that the artificial skylights would enable built environments to maintain long-term comfort and productivity.


Assuntos
Ritmo Circadiano/efeitos da radiação , Frequência Cardíaca/efeitos da radiação , Iluminação/métodos , Melatonina/análise , Adulto , Nível de Alerta/efeitos da radiação , Eletrocardiografia/efeitos da radiação , Humanos , Luz , Masculino , Saliva/química , Adulto Jovem
4.
Int J Radiat Biol ; 95(9): 1236-1241, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31287351

RESUMO

Purpose: We investigated the radioprotective effect of endogenous melatonin release at different times associated with the circadian rhythm on head and neck radiotherapy. Materials and methods: Two groups of animals were subjected daily to 8 Gy single fraction radiotherapy in the head and neck region from 5:00 to 6:00 (the morning group) or from 19:00 to 20:00 (the evening group). Corresponding untreated groups served as controls. Submandibular glands from rats sacrificed on the seventh day after irradiation were assessed biochemically and histopathologically. Melatonin, malondialdehyde and superoxide dismutase levels in blood collected immediately prior to irradiation were measured with rat-specific ELISA kits. Results: In irradiated rats, melatonin, malondialdehyde and superoxide dismutase levels were significantly higher in the evening group than in the morning group. In nonirradiated rats, melatonin and superoxide dismutase levels were significantly higher in the evening group than in the morning group. The areas of seromucous acinar cells were similar between the irradiated and nonirradiated evening groups, but the area was higher in the evening irradiated group than in the morning irradiated group. Conclusion: Consideration of endogenous melatonin secretion associated with the circadian rhythm may offer new therapeutic solutions for the complications of head and neck radiotherapy.


Assuntos
Ritmo Circadiano/efeitos da radiação , Melatonina/metabolismo , Animais , Masculino , Malondialdeído/sangue , Melatonina/sangue , Ratos , Ratos Sprague-Dawley , Superóxido Dismutase/sangue
5.
Nutrients ; 11(7)2019 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-31277441

RESUMO

Vegetables, once harvested and stored on supermarket shelves, continue to perform biochemical adjustments due to their modular nature and their ability to retain physiological autonomy. They can live after being harvested. In particular, the content of some essential nutraceuticals, such as carotenoids, can be altered in response to environmental or internal stimuli. Therefore, in the present study, we wondered whether endogenous rhythms continue to operate in commercial vegetables and if so, whether vegetable nutritional quality could be altered by such cycles. Our experimental model consisted of rocket leaves entrained under light/darkness cycles of 12/12 h over 3 days, and then we examined free-run oscillations for 2 days under continuous light or continuous darkness, which led to chlorophyll and carotenoid oscillations in both constant conditions. Given the importance of preserving food quality, the existence of such internal rhythms during continuous conditions may open new research perspective in nutrition science. However, while chromatographic techniques employed to determine pigment composition are accurate, they are also time-consuming and expensive. Here we propose for the first time an alternative method to estimate pigment content and the nutritional quality by the use of non-destructive and in situ optical techniques. These results are promising for nutritional quality assessments.


Assuntos
Brassicaceae/metabolismo , Carotenoides/metabolismo , Clorofila A/metabolismo , Ritmo Circadiano , Armazenamento de Alimentos , Valor Nutritivo , Folhas de Planta/metabolismo , Verduras/metabolismo , Brassicaceae/efeitos da radiação , Carotenoides/efeitos da radiação , Clorofila A/efeitos da radiação , Ritmo Circadiano/efeitos da radiação , Embalagem de Alimentos , Fotoperíodo , Folhas de Planta/efeitos da radiação , Fatores de Tempo , Verduras/efeitos da radiação , Zeaxantinas/metabolismo
6.
J Strength Cond Res ; 33(10): 2608-2615, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31361730

RESUMO

Otani, H, Goto, T, Goto, H, Hosokawa, Y, and Shirato, M. Solar radiation exposure has diurnal effects on thermoregulatory responses during high-intensity exercise in the heat outdoors. J Strength Cond Res 33(10): 2608-2615, 2019-This study investigated the diurnal effects of variations in solar radiation associated with changing solar elevation angle on thermoregulatory responses during high-intensity exercise in the heat outdoors. Ten male high school soccer players completed two 2-hour soccer training sessions under a clear sky in the heat of summer. These sessions were commenced at 0900 hours (AM) and 1600 hours (PM) on separate days. Solar radiation and elevation angle were higher in AM (820-1,070 W·m and 45-69°) than PM (620-110 W·m and 34-10°: both p < 0.001). Neither ambient temperature (AM 29-32° C; PM 31-31° C) nor wet-bulb globe temperature was different between trials. Although mean skin temperature was not different between trials, infrared tympanic temperature was higher at the end of exercise in AM than PM (p < 0.001). Heart rate (p < 0.01) and body heat gain from the sun (p < 0.001) were greater during exercise in AM than PM. Dry heat loss was smaller, but evaporative heat loss was greater in AM than PM (both p < 0.001). Thermal sensation and rating of perceived exertion were similar between trials, but GPS measurements showed a less total distance and distance covered by walking, jogging, and running in AM than PM (p < 0.01). This study demonstrates a greater thermoregulatory strain in AM than PM during 2-hour high-intensity soccer training in the heat under a clear sky. This observation is accompanied by a progressive increase in environmental heat stress with rising solar radiation and elevation angle in AM and a greater body heat gain from the sun in AM compared with PM.


Assuntos
Regulação da Temperatura Corporal/efeitos da radiação , Exposição à Radiação , Futebol/fisiologia , Estresse Fisiológico/efeitos da radiação , Luz Solar , Adolescente , Temperatura Corporal , Regulação da Temperatura Corporal/fisiologia , Ritmo Circadiano/efeitos da radiação , Exercício/fisiologia , Frequência Cardíaca , Temperatura Alta , Humanos , Masculino , Estresse Fisiológico/fisiologia , Sensação Térmica , Perda Insensível de Água
7.
Yale J Biol Med ; 92(2): 259-270, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31249487

RESUMO

Circadian disruption has been linked to markers for poor health outcomes in humans and animal models. What is it about circadian disruption that is problematic? One hypothesis is that phase resetting of the circadian system, which occurs in response to changes in environmental timing cues, leads to internal desynchrony within the organism. Internal desynchrony is understood as acute changes in phase relationships between biological rhythms from different cell groups, tissues, or organs within the body. Do we have strong evidence for internal desynchrony associated with or caused by circadian clock resetting? Here we review the literature, highlighting several key studies from measures of gene expression in laboratory rodents. We conclude that current evidence offers strong support for the premise that some protocols for light-induced resetting are associated with internal desynchrony. It is important to continue research to test whether internal desynchrony is necessary and/or sufficient for negative health impact of circadian disruption.


Assuntos
Relógios Circadianos/fisiologia , Ritmo Circadiano/fisiologia , Periodicidade , Fotoperíodo , Animais , Relógios Circadianos/genética , Relógios Circadianos/efeitos da radiação , Ritmo Circadiano/genética , Ritmo Circadiano/efeitos da radiação , Regulação da Expressão Gênica/efeitos da radiação , Humanos , Luz , Núcleo Supraquiasmático/metabolismo , Núcleo Supraquiasmático/fisiopatologia , Núcleo Supraquiasmático/efeitos da radiação
8.
Can J Physiol Pharmacol ; 97(9): 863-871, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31251886

RESUMO

Circadian rhythms are an inherent property of physiological processes and can be disturbed by irregular environmental cycles, including artificial light at night (ALAN). Circadian disruption may contribute to many pathologies, such as hypertension, obesity, and type 2 diabetes, but the underlying mechanisms are not understood. Our study investigated the consequences of ALAN on cardiovascular and metabolic parameters in spontaneously hypertensive rats, which represent an animal model of essential hypertension and insulin resistance. Adult males were exposed to a 12 h light - 12 h dark cycle and the ALAN group experienced dim light at night (1-2 lx), either for 2 or 5 weeks. Rats on ALAN showed a loss of light-dark variability for systolic blood pressure, but not for heart rate. Moreover, a gradual increase of systolic blood pressure was recorded over 5 weeks of ALAN. Exposure to ALAN increased plasma insulin and hepatic triglyceride levels. An increased expression of metabolic transcription factors, Pparα and Pparγ, in the epididymal fat and a decreased expression of Glut4 in the heart was found in the ALAN group. Our results demonstrate that low-intensity ALAN can disturb blood pressure control and augment insulin resistance in spontaneously hypertensive rats, and may represent a serious risk factor for cardiometabolic diseases.


Assuntos
Pressão Sanguínea/efeitos da radiação , Ritmo Circadiano/fisiologia , Ritmo Circadiano/efeitos da radiação , Frequência Cardíaca/efeitos da radiação , Luz/efeitos adversos , Animais , Pressão Sanguínea/fisiologia , Relação Dose-Resposta à Radiação , Frequência Cardíaca/fisiologia , Insulina/sangue , Resistência à Insulina/fisiologia , Resistência à Insulina/efeitos da radiação , Leptina/sangue , Masculino , Ratos , Ratos Endogâmicos SHR
9.
J Photochem Photobiol B ; 197: 111537, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31247384

RESUMO

Light is the most prominent zeitgeber of the circadian system, which contains central and peripheral oscillators. Our previous studies found that light wavelength could influence the rhythms of melatonin synthesis and clock gene expression in the central oscillator of chicks. However, the effect of monochromatic light on the peripheral oscillator and the role of melatonin have yet to be clarified. In this study, 216 newly hatched chicks were divided into three groups (intact, sham operation and pinealectomy) and were raised under white (WL), red (RL), green (GL) or blue (BL) light for 14 days. Their plasma and livers were sampled at 6 time points with 4-h intervals. Plasma melatonin concentration and liver clock gene expression (cClock, cBmal1, cBmal2, cCry1, cCry2, cPer2, cPer3) were measured for circadian rhythm analysis. In intact and sham operation chicks under WL, all liver clock genes showed circadian expression along with oscillations in plasma melatonin. However, positive clock genes peaked at subjective night along with melatonin, while negative clock genes peaked at subjective day or the shifting time of day-night. Chick exposure to monochromatic light led to an unaltered circadian rhythmicity in plasma melatonin and liver clock genes; however, their rhythmic parameters were notably influenced. Compared to WL, GL enhanced the mesor and amplitude of melatonin and all kinds of clock genes, whereas RL had the opposite effect. Pinealectomy significantly decreased expression of liver clock genes, which was consistent with the reduction in plasma melatonin concentration, especially for the GL group, and resulted in the expression of liver clock genes showing low-mesor and low-amplitude oscillations as well as no statistically significant differences among the monochromatic light groups. Thus, we speculated that melatonin plays a key role in the effects of light wavelength on clock gene rhythm in the chick liver.


Assuntos
Proteínas CLOCK/metabolismo , Ritmo Circadiano/genética , Regulação da Expressão Gênica/efeitos da radiação , Luz , Fígado/metabolismo , Melatonina/sangue , Animais , Proteínas CLOCK/genética , Galinhas , Ritmo Circadiano/efeitos da radiação
10.
Mamm Genome ; 30(3-4): 54-62, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-31020388

RESUMO

Spermatogenesis-associated protein 13 (Spata13) is a guanine nucleotide exchange factor (GEF) enriched in discrete brain regions in the adult, with pronounced expression in the extended central amygdala (CeA). Loss of Spata13, also known as the adenomatous polyposis coli exchange factor Asef2, has no identifiable phenotype although it has been shown to reduce the number and size of intestinal tumours in Apc (Min/+) mice. Nevertheless, its brain-related functions have not been investigated. To pursue this, we have generated a Spata13 knockout mouse line using CRISPR-mediated deletion of an exon containing the GTPase domain that is common to multiple isoforms. Homozygous mutants were viable and appeared normal. We subjected both male and female cohorts to a comprehensive battery of behavioural tests designed to investigate particular CeA-related functions. Here, we show that Spata13 modulates social behaviour with homozygous mutants being subordinate to wildtype controls. Furthermore, female homozygotes show increased activity in home cages during the dark phase of the light-dark cycle. In summary, Spata13 modulates social hierarchy in both male and female mice in addition to affecting voluntary activity in females.


Assuntos
Ritmo Circadiano/efeitos da radiação , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Comportamento Social , Animais , Comportamento Animal/efeitos da radiação , Feminino , Fatores de Troca do Nucleotídeo Guanina/genética , Hierarquia Social , Humanos , Masculino , Camundongos , Camundongos Knockout , Fotoperíodo , Predomínio Social
11.
J Photochem Photobiol B ; 194: 107-118, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30953912

RESUMO

The association between light pollution and disruption of daily rhythms, metabolic and hormonal disorders, as well as cancer progression is well-recognized. These adverse effects could be due to nocturnal melatonin suppression. The signaling pathway by which light pollution affects metabolism and endocrine responses is unclear. We studied the effects of artificial light at night (ALAN1) on body mass, food and water intake, daily rhythms of body temperature, serum glucose and insulin in male rats. Daily rhythms of urine production and urinary 6-sulfatoxymelatonin (6-SMT2), as well as global DNA methylation in pancreas and liver tissues were also assessed. Mass gain was higher in ALAN rats compared with controls. Food intake, water consumption, glucose, insulin, and 6-SMT levels markedly lessened in response to ALAN. Conversely, urine production and body temperature were elevated in ALAN rats compared with controls. Significant 24-h rhythms were detected for all variables that were altered in mesor, amplitude, and acrophase occurrences under ALAN conditions. DNA hypo-methylation was detected in ALAN pancreatic tissue compared with controls, but not in hepatic tissue. Overall, ALAN affects metabolic and hormonal physiology in different levels in which flexible crosstalk between melatonin and both epigenetics and metabolic levels expressed as body temperature rhythm, is suggested to mediate the environmental exposure at the molecular level and subsequently physiology is altered. The flexibility of epigenetic modifications provides a potential therapeutic target for rectifying ALAN adverse effects by epigenetic markers such as melatonin and behavioral lifestyle interventions for confining ALAN exposures as much as possible.


Assuntos
Metilação de DNA/efeitos da radiação , Hormônios/metabolismo , Luz , Animais , Glicemia/metabolismo , Temperatura Corporal/efeitos da radiação , Ritmo Circadiano/efeitos da radiação , Ingestão de Líquidos/efeitos da radiação , Metabolismo Energético/efeitos da radiação , Epigênese Genética/efeitos da radiação , Insulina/sangue , Masculino , Melatonina/análogos & derivados , Melatonina/urina , Ratos , Fatores de Tempo
12.
Photosynth Res ; 141(1): 83-97, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30891661

RESUMO

Prediction of stomatal conductance is a key element to relate and scale up leaf-level gas exchange processes to canopy, ecosystem and land surface models. The empirical models that are typically employed for this purpose are simple and elegant formulations which relate stomatal conductance on a leaf area basis to the net rate of CO2 assimilation, humidity and CO2 concentration. Although light intensity is not directly modelled as a stomatal opening cue, it is well-known that stomata respond strongly to light. One response mode depends specifically on the blue-light part of the light spectrum, whereas the quantitative or 'red' light response is less spectrally defined and relies more on the quantity of incident light. Here, we present a modification of an empirical stomatal conductance model which explicitly accounts for the stomatal red-light response, based on a mesophyll-derived signal putatively initiated by the chloroplastic plastoquinone redox state. The modified model showed similar prediction accuracy compared to models using a relationship between stomatal conductance and net assimilation rate. However, fitted parameter values with the modified model varied much less across different measurement conditions, lessening the need for frequent re-parameterization to different conditions required of the current model. We also present a simple and easy to parameterize extension to the widely used Farquhar-Von Caemmerer-Berry photosynthesis model to facilitate coupling with the modified stomatal conductance model, which should enable use of the new stomatal conductance model to simulate ecosystem water vapour exchange in terrestrial biosphere models.


Assuntos
Luz , Estômatos de Plantas/fisiologia , Estômatos de Plantas/efeitos da radiação , Plastoquinona/metabolismo , Ritmo Circadiano/efeitos da radiação , Fluorescência , Modelos Biológicos , Movimento , Oxirredução/efeitos da radiação , Fotossíntese/efeitos da radiação , Reprodutibilidade dos Testes
13.
Biochem Biophys Res Commun ; 512(2): 344-351, 2019 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-30894276

RESUMO

Ultraviolet-C (UVC) electromagnetic radiation is the most damaging type of the UV radiation and causes many cellular and physiological responses. UVC has been using for sterilization and disinfection, and the risk of exposure to the UVC is increasing. Here, we determined the effect of the UVC on the cellular circadian clock system. UVC irradiation synchronized the biological clock system and induced time-dependent expression of clock genes including Clock, Cry1, and Per1. The rhythmic expression of clock genes is also followed by time-dependent mRNA degradation or non-canonical translation initiation of clock genes. Furthermore, we show a translocation of PERIOD1 (PER1) protein after UVC irradiation, which mediates the rhythmic feedback loop of clock genes. Our results suggest that UVC can synchronize the circadian clock system, and induces rhythmic expression of clock genes via time-dependent transcription, post-transcription, and post-translational modification.


Assuntos
Ritmo Circadiano/efeitos da radiação , Raios Ultravioleta , Transporte Ativo do Núcleo Celular/efeitos da radiação , Animais , Ritmo Circadiano/genética , Ritmo Circadiano/fisiologia , Criptocromos/genética , Criptocromos/metabolismo , Fibroblastos/fisiologia , Fibroblastos/efeitos da radiação , Camundongos , Células NIH 3T3 , Proteínas Circadianas Period/genética , Proteínas Circadianas Period/metabolismo , Biossíntese de Proteínas/efeitos da radiação , Estabilidade de RNA/efeitos da radiação , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
14.
PLoS One ; 14(3): e0214046, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30921336

RESUMO

PURPOSE: The circadian clock is entrained to light by the intrinsically photosensitive retinal ganglion cells. Loss of these cells in glaucoma, an eye disease with loss of retinal ganglion cells as its key feature, might thus result in a change in chronotype. We aimed to compare the chronotype between glaucoma patients and healthy subjects. METHODS: We sent the Munich ChronoType Questionnaire to 221 glaucoma patients (response rate 81%); controls (primary control group) were primarily their spouses. After exclusion of shift workers and participants who woke-up due to an alarm clock on days off, 159 glaucoma patients (88 early, 21 moderate, 23 severe) and 163 controls remained. We calculated chronotype as the mid-sleep on days off, corrected for workweek accumulated sleep debt (MSFsc). We compared means and variances between groups using Welch's tests and F-tests, respectively. A secondary control group was recruited from participants in a citizen-science project (n = 17073) who completed an online questionnaire. A resampling method was applied to enable an age- and gender- matched comparison with the glaucoma patients. RESULTS: Compared to the primary control group, glaucoma did not affect the mean MSFsc (controls 3:47; early, moderate, and severe glaucoma 3:40, 3:45, and 3:33, respectively [P = 0.62]). Chronotype variability seemed to increase with increasing disease severity (severe glaucoma versus controls: P = 0.023). The mean MSFsc of the secondary control group was 3:50 (95% confidence interval 3:48 to 3:52); significantly later than that of the glaucoma patients (3:40; P = 0.024). Mean MSFsc did not differ significantly between the control groups (P = 0.42). CONCLUSIONS: No clear changes were found in the chronotype as determined by sleep phase in patients with glaucoma, especially not in early and moderate glaucoma. In severe glaucoma, chronotype variability seems to increase, possibly alongside a small advancement.


Assuntos
Ritmo Circadiano/fisiologia , Glaucoma de Ângulo Aberto/fisiopatologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Relógios Circadianos/fisiologia , Relógios Circadianos/efeitos da radiação , Ritmo Circadiano/efeitos da radiação , Feminino , Humanos , Luz , Masculino , Pessoa de Meia-Idade , Células Ganglionares da Retina/fisiologia , Células Ganglionares da Retina/efeitos da radiação , Sono/fisiologia , Inquéritos e Questionários , Fatores de Tempo , Vigília/fisiologia
15.
Environ Pollut ; 248: 565-573, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30831353

RESUMO

Coastal habitats, in particular sandy beaches, are becoming increasingly exposed to artificial light pollution at night (ALAN). Yet, only a few studies have this far assessed the effects of ALAN on the species inhabiting these ecosystems. In this study we assessed the effects of ALAN on Tylos spinulosus, a prominent wrack-consumer isopod living in sandy beaches of north-central Chile. This species burrows in the sand during daylight and emerges at night to migrate down-shore, so we argue it can be used as a model species for the study of ALAN effects on coastal nocturnal species. We assessed whether ALAN alters the distribution and locomotor activity of this isopod using a light system placed in upper shore sediments close to the edge of the dunes, mimicking light intensities measured near public lighting. The response of the isopods was compared to control transects located farther away and not exposed to artificial light. In parallel, we measured the isopods' locomotor activity in the laboratory using actographs that recorded their movement within mesocosms simulating the beach surface. Measurements in the field indicated a clear reduction in isopod abundance near the source of the light and a restriction of their tidal distribution range, as compared to control transects. Meanwhile, the laboratory experiments showed that in mesocosms exposed to ALAN, isopods exhibited reduced activity and a circadian rhythm that was altered and even lost after a few days. Such changes with respect to control mesocosms with a natural day/night cycle suggest that the changes observed in the field were directly related to a disruption in the locomotor activity of the isopods. All together these results provide causal evidence of negative ALAN effects on this species, and call for further research on other nocturnal sandy beach species that might become increasingly affected by ALAN.


Assuntos
Ritmo Circadiano/efeitos da radiação , Poluição Ambiental/efeitos adversos , Isópodes/fisiologia , Iluminação/efeitos adversos , Locomoção/efeitos da radiação , Animais , Chile , Ecossistema
16.
Curr Psychiatry Rep ; 21(3): 14, 2019 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-30826893

RESUMO

PURPOSE OF REVIEW: Disruptions in circadian rhythms are believed to underlie the illness course of bipolar disorder (BD). This review evaluates recent studies on the treatment of circadian dysfunction in BD. RECENT FINDINGS: Targeted social rhythm therapy may be useful for bipolar depression though some studies suggest that a non-targeted psychosocial or pharmacological intervention may be just as efficacious. Lithium holds potential for addressing circadian dysfunction in BD. Blue-blocking therapy may be useful for mania and midday bright light therapy may relieve depression. CONCLUSIONS: Psychosocial, pharmacological, and light-based approaches are promising avenues for treating circadian dysfunction in BD.


Assuntos
Transtorno Bipolar/fisiopatologia , Transtorno Bipolar/terapia , Ritmo Circadiano/efeitos dos fármacos , Ritmo Circadiano/efeitos da radiação , Transtorno Bipolar/complicações , Transtorno Bipolar/psicologia , Depressão/complicações , Depressão/fisiopatologia , Depressão/terapia , Transtorno Depressivo/complicações , Transtorno Depressivo/fisiopatologia , Transtorno Depressivo/terapia , Humanos , Compostos de Lítio/uso terapêutico , Fototerapia
17.
Int J Mol Sci ; 20(4)2019 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-30781538

RESUMO

The human skin is the outermost physical barrier and has its own circadian machinery that works either cooperatively with the central clock, or autonomously. Circadian rhythms have been observed in many functions related to epidermal homeostasis including hydration and inflammation, and this functional oscillation is disturbed by ultraviolet radiation (UVR), which is a strong environmental cue. Among the genes estimated to show circadian expression in the skin, metalloproteinase inhibitor 3 (TIMP3), has a rhythmic expression in synchronized human keratinocytes similar to that of the core clock gene PER1 and an epidermal circadian regulatory gene, aquaporin 3 (AQP3) but was antiphase to the core clock gene BMAL1. Tumor necrosis factor-α (TNF-α), the regulatory target of TIMP3 via a disintegrin and metalloproteinase domain 17 (ADAM17), was inversely regulated when TIMP3 expression was downregulated by ultraviolet B (UVB) treatment. When synthetic TIMP3 peptides were applied to the cells, the secretion of TNF-α did not increase following the UVB treatment. Similar to TIMP3 peptides, Camellia sinensis leaf-derived extracts showed a distinguishing efficacy in recovering TIMP3 expression, downregulated by UVB treatment. Together, our results suggest that TIMP3 reversely mediates UVR-induced inflammation by being highly expressed during the daytime; therefore, recovering the circadian expression of TIMP3 using synthetic TIMP3 peptides or bioactive natural ingredients could at least in part inhibit the UVR-induced cellular phenomena.


Assuntos
Camellia sinensis/química , Inflamação/tratamento farmacológico , Extratos Vegetais/farmacologia , Inibidor Tecidual de Metaloproteinase-3/genética , Proteína ADAM17/genética , Fatores de Transcrição ARNTL/genética , Aquaporina 3/genética , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Ritmo Circadiano/efeitos dos fármacos , Ritmo Circadiano/genética , Ritmo Circadiano/efeitos da radiação , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Regulação da Expressão Gênica no Desenvolvimento/efeitos da radiação , Humanos , Inflamação/genética , Inflamação/patologia , Proteínas Circadianas Period/genética , Extratos Vegetais/química , Fator de Necrose Tumoral alfa/genética , Raios Ultravioleta
18.
Biochemistry ; 58(14): 1878-1891, 2019 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-30768260

RESUMO

The tiny picoalga, Ostreococcus tauri, originating from the Thau Lagoon is a member of the marine phytoplankton. Because of its highly reduced genome and small cell size, while retaining the fundamental requirements of a eukaryotic photosynthetic cell, it became a popular model organism for studying photosynthesis or circadian clock-related processes. We analyzed the spectroscopic properties of the photoreceptor domain of the histidine kinase rhodopsin Ot-HKR that is suggested to be involved in the light-induced entrainment of the Ostreococcus circadian clock. We found that the rhodopsin, Ot-Rh, dark state absorbs maximally at 505 nm. Exposure to green-orange light led to the accumulation of a blue-shifted M-state-like absorbance form with a deprotonated Schiff base. This Ot-Rh P400 state had an unusually long lifetime of several minutes. A second long-living photoproduct with a red-shifted absorbance, P560, accumulated upon illumination with blue/UVA light. The resulting photochromicity of the rhodopsin is expected to be advantageous to its function as a molecular control element of the signal transducing HKR domains. The light intensity and the ratio of blue vs green light are reflected by the ratio of rhodopsin molecules in the long-living absorbance forms. Furthermore, dark-state absorbance and the photocycle kinetics vary with the salt content of the environment substantially. This observation is attributed to anion binding in the dark state and a transient anion release during the photocycle, indicating that the salinity affects the photoinduced processes.


Assuntos
Proteínas de Algas/metabolismo , Clorófitas/metabolismo , Receptor Quinase 1 Acoplada a Proteína G/metabolismo , Histidina Quinase/metabolismo , Rodopsina/metabolismo , Água do Mar/microbiologia , Proteínas de Algas/genética , Sequência de Aminoácidos , Clorófitas/genética , Clorófitas/efeitos da radiação , Relógios Circadianos/efeitos da radiação , Ritmo Circadiano/efeitos da radiação , Receptor Quinase 1 Acoplada a Proteína G/genética , Histidina Quinase/genética , Cinética , Luz , Rodopsina/genética , Salinidade , Água do Mar/química , Homologia de Sequência de Aminoácidos , Transdução de Sinais/efeitos da radiação , Espectroscopia de Infravermelho com Transformada de Fourier
20.
New Phytol ; 222(3): 1364-1379, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30636322

RESUMO

Photoacclimation consists of short- and long-term strategies used by photosynthetic organisms to adapt to dynamic light environments. Observable photophysiology changes resulting from these strategies have been used in coarse-grained models to predict light-dependent growth and photosynthetic rates. However, the contribution of the broader metabolic network, relevant to species-specific strategies and fitness, is not accounted for in these simple models. We incorporated photophysiology experimental data with genome-scale modeling to characterize organism-level, light-dependent metabolic changes in the model diatom Phaeodactylum tricornutum. Oxygen evolution and photon absorption rates were combined with condition-specific biomass compositions to predict metabolic pathway usage for cells acclimated to four different light intensities. Photorespiration, an ornithine-glutamine shunt, and branched-chain amino acid metabolism were hypothesized as the primary intercompartment reductant shuttles for mediating excess light energy dissipation. Additionally, simulations suggested that carbon shunted through photorespiration is recycled back to the chloroplast as pyruvate, a mechanism distinct from known strategies in photosynthetic organisms. Our results suggest a flexible metabolic network in P. tricornutum that tunes intercompartment metabolism to optimize energy transport between the organelles, consuming excess energy as needed. Characterization of these intercompartment reductant shuttles broadens our understanding of energy partitioning strategies in this clade of ecologically important primary producers.


Assuntos
Diatomáceas/metabolismo , Diatomáceas/efeitos da radiação , Luz , Aclimatação/efeitos da radiação , Oxirredutases do Álcool/metabolismo , Biomassa , Respiração Celular/efeitos da radiação , Ritmo Circadiano/efeitos da radiação , Simulação por Computador , Transporte de Elétrons/efeitos da radiação , Redes e Vias Metabólicas/efeitos da radiação , Mitocôndrias/metabolismo , Mitocôndrias/efeitos da radiação , Modelos Biológicos , Fotossíntese/efeitos da radiação , Ácido Pirúvico/metabolismo
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