Significant Rhythm Research Articles

Seasonal Immune Rhythms of head kidney and spleen cells in the freshwater Teleost, Channa punctatus

Annual rhythms in immune function are the reflection of a crucial physiological strategy to deal with environmental stressors. The fish are pivotal animal models to study the annual rhythm and to understand the evolution of the vertebrate biological system. The current research was planned to assess the annual changes in the innate immune functions of immune cells in a teleost, Channa punctatus. Head kidney and splenic macrophage phagocytosis, superoxide generation, and nitrite release were evaluated to assess innate immunity. Cell-mediated immunity was measured through head kidney and splenic lymphocyte proliferation in presence of mitogens. The superoxide anion generation by the cells of head kidney and spleen was maximum in October. A bimodal pattern in nitrite production was observed with the first peak in November and the second in March. Cosinor analysis revealed a statistically significant annual rhythm in nitrite production. Similarly, phagocytosis and lymphocyte proliferation also showed statistically significant annual rhythms. It was concluded that animals maintain an optimum immune response in seasonally changing environments. Elevated immunity during certain times of the year might assist animals deal with seasonal environmental stressors. Further research may be focused upon measuring survival rate and reproductive success after season induced elevated immunity.

Habitual nappers and non-nappers differ in circadian rhythms of LIPE expression in abdominal adipose tissue explants.

Napping is a widespread practice worldwide and has in recent years been linked to increased abdominal adiposity. Lipase E or LIPE encodes the protein hormone-sensitive lipase (HSL), an enzyme that plays an important role in lipid mobilization and exhibits a circadian expression rhythm in human adipose tissue. We hypothesized that habitual napping may impact the circadian expression pattern of LIPE, which in turn may attenuate lipid mobilization and induce abdominal fat accumulation. Abdominal adipose tissue explants from participants with obesity (n = 17) were cultured for a 24-h duration and analyzed every 4 h. Habitual nappers (n = 8) were selected to match non-nappers (n = 9) in age, sex, BMI, adiposity, and metabolic syndrome traits. Circadian LIPE expression rhythmicity was analyzed using the cosinor method. Adipose tissue explants exhibited robust circadian rhythms in LIPE expression in non-nappers. In contrast, nappers had a flattened rhythm. LIPE amplitude was decreased in nappers as compared with non-nappers (71% lower). The decrease in amplitude among nappers was related to the frequency of napping (times per week) where a lower rhythm amplitude was associated with a higher napping frequency (r = -0.80; P = 0.018). Confirmatory analyses in the activity of LIPE's protein (i.e., HSL) also showed a significant rhythm in non-nappers, whereas significance in the activity of HSL was lost among nappers. Our results suggest that nappers display dysregulated circadian LIPE expression as well as dysregulated circadian HSL activity, which may alter lipid mobilization and contribute to increased abdominal obesity in habitual nappers.

0028 Systematic Review: Time of day differences in complete blood count values

Abstract Introduction The complete blood count (CBC) is the most commonly ordered blood test with a large range of reference values that do not consider time of day for interpretation. Clinicians are largely unfamiliar with the influence of time of day on CBC values. Our objective was to systematically review this topic to report on peak and trough timing of CBC values. Methods A systematic search of PubMed, Ovid, Scopus, CINAHL, Cochrane, Embase, and Web of Science was performed for studies evaluating any part of the CBC over 24 hours. The studies were screened for eligibility based on predetermined criteria including: measurement of a part of the CBC with at least 3 time points in 24 hours. In total, 164 full-text articles were screened and 32 were included in the final analysis. The aggregated data was analyzed with the Cosinor package of R statistical environment and Stata SE to create cosinor graphs and Forest plots for each component of the CBC, respectively. Results Of the 32 articles, a metalysis was performed on the following CBC subsets: leukocytes, erythrocytes, hemoglobin, hematocrit, platelets, neutrophils, lymphocytes, monocytes, eosinophils, and basophils. Lymphocytes exhibited a statistically significant diurnal rhythm (p=0.014, n=10 articles) with a peak of 2280.10 cells/uL at 23:17 (CI: 1731.80, 2828.40) and trough of 1661.49 cells/uL at 08:53 (CI: 1242.64, 2080.33). Erythrocytes, hemoglobin, and hematocrit peaked in the morning; while platelets, neutrophils, monocytes, and basophils peaked in the late afternoon and early evening; and lymphocytes and eosinophils peaked late at night. High heterogeneity in the results across studies was noted, likely attributable to the difference in circadian factors controlled. Limitations include the small sample size for each component of the CBC, the limited samples included in the meta analysis, and the significant heterogeneity affecting the results. Conclusion There are significant time of day changes in CBC values that might be important to consider as we move towards precision medicine. Given the limited number of studies with small sample sizes, future work should evaluate large data sources to inform time-dependent interpretation of the CBC. Support (if any)

Co-expression of diurnal and ultradian rhythms in the plasma metabolome of common voles (Microtus arvalis).

Metabolic rhythms include rapid, ultradian (hourly) dynamics, but it remains unclear what their relationship to circadian metabolic rhythms is, and what role meal timing plays in coordinating these ultradian rhythms in metabolism. Here, we characterized widespread ultradian rhythms under ad libitum feeding conditions in the plasma metabolome of the vole, the gold standard animal model for behavioral ultradian rhythms, naturally expressing ~2-h foraging rhythms throughout the day and night. These ultradian metabolite rhythms co-expressed with diurnal 24-h rhythms in the same metabolites and did not align with food intake patterns. Specifically, under light-dark entrained conditions we showed twice daily entrainment of phase and period of ultradian behavioral rhythms associated with phase adjustment of the ultradian cycle around the light-dark and dark-light transitions. These ultradian activity patterns also drove an ultradian feeding pattern. We used a unique approach to map this behavioral activity/feeding status to high temporal resolution (every 90min) measures of plasma metabolite profiles across the 24-h light-dark cycle. A total of 148 known metabolites were detected in vole plasma. Supervised, discriminant analysis did not group metabolite concentration by feeding status, instead, unsupervised clustering of metabolite time courses revealed clusters of metabolites that exhibited significant ultradian rhythms with periods different from the feeding cycle. Two clusters with dissimilar ultradian dynamics, one lipid-enriched (period=3.4h) and one amino acid-enriched (period=4.1h), both showed co-expression with diurnal cycles. A third cluster solely comprised of glycerophospholipids (specifically ether-linked phosphatidylcholines) expressed an 11.9h ultradian rhythm without co-expressed diurnal rhythmicity. Our findings show coordinated co-expression of diurnal metabolic rhythms with rapid dynamics in feeding and metabolism. These findings reveal that ultradian rhythms are integral to biological timing of metabolic regulation, and will be important in interpreting the impact of circadian desynchrony and meal timing on metabolic rhythms.

Differential expression of Tet family genes and their potential role in regulating skeletal muscle development of Siniperca chuatsi

DNA methylation and demethylation are crucial epigenetic modification and regulation for animal development, and their dynamic changes may affect skeletal muscle development. The ten-eleven translocation (Tet) family proteins are demethylases which are involved in the dynamic changes of DNA methylation. However, the expression pattern of Tet family genes and their role in myogenesis in fish remains unclear. In this study, the temporal and spatial expression profiles of Tet1, Tet2 and Tet3 were assayed with RT-qPCR techniques in Chinese perch, Siniperca chuatsi. The obtained data showed that three Tet family genes were differentially expressed at different development stages. Tet1 was expressed low at blastula stage, but highly expressed at gastrula stage, then remained low until hatching. The expressions of Tet2 and Tet3 were significantly increased at late gastrula and kept high expression before hatching stage. At the spatial level, the Tet1 expression was highest in gill tissue, moderate level in brain and slow muscle. Tet2 was similar to that of Tet1 except that it was expressed at a lower level in slow muscle, and Tet3 exhibited a higher expression level in gill and brain, a moderate level in fast muscle. Cosinor analysis turned out that the expression of Tet1 and Tet2 displayed a significant daily rhythm in fast muscle, but Tet3 did not show daily rhythmicity. Inhibiting the activity of Tet1/2 proteins by injecting Bobcat339 significantly reduced the expression of MyoD and MRF4, but not MyoG and Myf5, by which leads to the increase of the number of satellite cells and proliferating myoblasts. Together, the results suggest that Tet1/2 may target to MyoD and MRF4 resulted in DNA demethylation and promoting their expression, thus stimulating myoblast differentiation.

Daily rhythm of dynamic cerebral autoregulation in patients after stroke

Dynamic cerebral autoregulation (dCA) in healthy young adults displays a daily variation. Whether the rhythm exists in patients with stroke is unknown. We studied 28 stroke patients (age: 26–83 years, 7 females) within 48 hours after thrombolysis. dCA was assessed 54 times in these patients during supine rest (twice in 26 and once in 2 patients): 9 assessments between 0–9AM, 12 between 9AM–2PM, 20 between 2–7PM, and 13 between 7PM–12AM. To estimate dCA, phase shifts between spontaneous oscillations of cerebral blood flow velocity (CBFV) in the middle cerebral artery and arterial blood pressure (BP) were obtained in four frequency bands: <0.05 Hz, 0.05–0.1 Hz, 0.1–0.2 Hz, and >0.2 Hz. CBFV-BP phase shifts at <0.05 Hz were significantly larger between 2–7PM, suggesting better dCA, than those at other times (p < 0.0001), and the daily rhythm was consistent for stroke and non-stroke sides. No significant rhythms were observed at higher frequencies (all p > 0.2). All results were independent of age, sex, stroke type and severity, and other cardiovascular conditions. dCA after stroke showed a daily rhythm, leading to a better regulation of CBFV at <0.05 Hz during the afternoon. The finding may have implications for daily activity management of stroke patients.

A portable feedback-controlled pump for monitoring eye outflow facility in conscious rats.

Intraocular pressure (IOP) is heavily influenced by the resistance of trabecular outflow pathways through which most of the aqueous humor produced by the eye continuously drains. The standard method of quantifying outflow resistance and other aspects of ocular fluid dynamics is eye cannulation, which allows for direct measurement and manipulation of IOP and flow in animal models. Since the method is invasive, indirect techniques that are slower and less accurate must be used for chronological studies. A novel technology is introduced that can autonomously measure outflow facility in conscious rats multiple times a day. A smart portable micropump infuses fluid into the eye through a permanently-implanted cannula and dynamically adjusts flow rate using a unique proportional feedback algorithm that sets IOP to a target level, even though IOP fluctuates erratically in awake free-moving animals. Pressure-flow data collected by the system from anesthetized rats were validated against intraocular recordings with commercial pressure and flow sensors. System and sensor estimates of outflow facility were indistinguishable, averaging 23 ± 3 nl·min-1·mmHg-1 across animals (n = 11). Pressure-flow data were then collected round-the-clock for several days from conscious rats, while outflow facility was measured every few hours. A significant diurnal facility rhythm was observed in every animal (n = 4), with mean daytime level of 22 ± 10 nl·min-1·mmHg-1 and mean nighttime level of 15 ± 7 nl·min-1·mmHg-1. The rhythm correlated with diurnal changes in IOP and likely contributed prominently to those changes based on the day-night swing in facility magnitude. Hence, the portable smart pump offers a unique tool for repeated long-term monitoring of outflow facility and other possible parameters of ocular health. It could also be useful in animal glaucoma studies for reversibly inducing acute or chronic ocular hypertension without explicitly damaging trabecular outflow pathways.

СТАН СЕРЦЕВО-СУДИННОЇ СИСТЕМИ У ХВОРИХ ІЗ ЗАДИШКОЮ, ЯКІ ПЕРЕНЕСЛИ ПНЕВМОНІЮ, АСОЦІЙОВАНУ З COVID-19

The aim of this study is to determine the contribution of cardiovascular system impairment to the development of dyspnea in post-acute COVID-19 pneumonia patients. Materials and methods. A total of 108 patients with dyspnea in the post-acute phase of COVID-19 (at 47 (38; 62) days after the onset of symptoms) were examined. These patients had experienced COVID-19associated pneumonia between April and November 2021. 21 patients were excluded due to comorbidities that could be a potential cause of dyspnea in the post-COVID-19 period. Thus, a group of 87 patients was formed, with an average age of 56 (49; 65) years, including 42 (48.3%) males. Patients were divided into three subgroups based on the severity of their acute COVID-19 illness: subgroup 1 (35 patients) — moderate, subgroup 2 (37 patients) — severe and subgroup 3 (15 patients) with critical. Investigation methods included clinical examinations, the mMRC dyspnea questionnaire, chest CT scans (both anamnestic and during examination), spirometry, ECG, echo-Doppler, serum NT-proBNP levels. Results. Patients in subgroups 1 and 2 in the post-acute phase of COVID-19 had less pronounced dyspnea compared to patients in subgroup 3 (1 (1; 2) and 2 (1; 3) vs. 3 (2; 4), respectively) (p &lt; 0.001). Residual changes on chest CT scans were more frequently observed in subgroup 3 than in subgroups 1 and 2 (15 (100%) vs. 7 (20.0%) and 20 (54.1%), respectively) (p &lt; 0.001). Obstructive ventilation disorders were only observed in subgroups 1 and 2 (in 15 (42.9%) and 6 (16.2%) patients, respectively), while restrictive disorders were found in subgroups 2 and 3 (in 14 (37.8%) and 12 (80.0%) patients, respectively). Clinically significant rhythm or conduction disturbances were not detected on ECG in any patient. According to echo-Doppler, subgroup 1 had diastolic dysfunction of the left ventricle (LV) in 3 (8.5%) patients; subgroup 2 had diastolic dysfunction of both the LV and right ventricle (RV) in 5 (13.5%) and 4 (10.8%) patients, respectively; and subgroup 3 had diastolic dysfunction of both the LV and RV in 4 (26.7%) patients. Mild pulmonary hypertension was observed only in subgroups 2 and 3 (in 13 (35.1%) and 14 (93.3%) patients, respectively). Elevated NT-proBNP levels were found in 22.9% of patients, with no significant differences between subgroups (p &gt; 0.05). Conclusions. The severity of dyspnea in the post-acute phase of COVID-19 is related to the duration of lung involvement and the severity of the acute illness. In patients with moderate-severity acute COVID-19, dyspnea in the post-acute phase is primarily due to residual respiratory system changes (in 20.0% of patients) and mild obstructive ventilation disorders (in 42.9% of patients). Cardiovascular system involvement in these patients is mainly detected by elevated serum NT-proBNP levels (in 22.9% of patients), which may serve as a marker for the heart failure onset, necessitating consultation with a cardiologist. In patients with severe- acute COVID-19, dyspnea in the post-acute phase is due to residual morphological lesions in the respiratory system based on chest CT findings (in 54.1% of patients) and cardiovascular pathology (in 45.9% of patients). Therefore, managing this patient cohort in the post-acute phase requires collaboration between pulmonologists and cardiologists, especially when dyspnea does not correlate with morphological lesions in the respiratory system on chest CT. In patients with critical acute COVID-19, dyspnea in the post-acute phase is consistently caused by both residual morphological lesions in the respiratory system (in 100% of patients) and cardiovascular pathology (in 93.3% of patients). This substantiates the imperative for joint management by pulmonologists and cardiologists.

Effects of constant light and dark conditions on the locomotor activity, body mass, and body temperature rhythms of Eurasian Tree Sparrows (Passer montanus)

Light is an essential environmental cue influencing the endogenous circadian clocks that regulate behavioral and physiological processes in animals. Despite extensive research on the circadian rhythms of avian behavior and physiology, the mechanisms by which they adapt and adjust to abnormal photoperiod conditions, such as artificial light, have yet to be fully elucidated. Here, the circadian rhythms of the body mass, activity, and core and peripheral body temperatures of the Eurasian Tree Sparrow (Passer montanus, ETS)—a diurnal passerine—were examined under three different lighting conditions: constant light (LL), constant darkness (DD), and normal light–dark cycles (LD). Our results showed that the activity, body mass, core, tarsometatarsus, and eye temperatures of the ETSs varied significantly with treatment, time, and the interaction between treatment and time; however, there was no significant change in body mass in response to the interaction between time and treatment. Under LD conditions, the ETSs exhibited significant circadian rhythms in activity and core, tarsometatarsus, and eye temperatures. Under LL conditions, only the core temperature exhibited significant rhythmicity. Under DD conditions, there were no significant circadian rhythms in activity, body mass, and eye temperature; however, the core and tarsometatarsus temperatures remained rhythmic. Our results indicate that the core body temperature rhythm of ETS is endogenous and can be maintained under abnormal photoperiods. In contrast, the activity and body surface temperature, uncoupled from the core body temperature under abnormal photoperiod conditions, strongly depend on light. These results differ from those of other diurnal avian species, suggesting a unique coping mechanism of ETS in response to an abnormal photoperiod.

Circadian rhythmicity of amyloid-beta-related molecules is disrupted in the choroid plexus of a female Alzheimer's disease mouse model.

The choroid plexus (CP) is part of the blood-cerebrospinal fluid barrier (BCSFB) and was recently described as an important component of the circadian clock system. It is the principal source of cerebrospinal fluid (CSF) and responsible for the synthesis and secretion of various neuroprotective peptides including those involved in amyloid-β (Aβ) transport/degradation, contributing to Aβ homeostasis. Inadequate Aβ metabolic clearance and transport across the BCSFB have been associated with circadian dysfunctions in Alzheimer's disease (AD) patients. To investigate whether AD pathology influences Aβ scavengers circadian expression, we collected CP at different time points from an AD mouse model (APP/PS1) (female and male animals, aged 6- and 12-months-old) and analyzed their mRNA expression by Real-time RT-PCR. Only angiotensin-converting enzyme (Ace) expression in 6-month-old female wild-type mice and transthyretin (Ttr) expression in 12-month-old female wild-type mice presented significant rhythmicity. The circadian rhythmicity of Ace and Ttr, prompt us to analyze the involvement of circadian rhythm in Aβ uptake. A human CP papilloma (HIBCPP) cell line was incubated with Aβ-488 and uptake was evaluated at different time points using flow cytometry. Aβ uptake displayed circadian rhythmicity. Our results suggest that AD might affect Aβ scavengers rhythmicity and that Aβ clearance is a rhythmic process possibly regulated by the rhythmic expression of Aβ scavengers.

Structural characteristics of orexin receptor type 2 in Pacific abalone and its diurnal expression pattern after fasting and re-feeding

Pacific abalone (Haliotis discus hannai) is a typical nocturnal organism. To examine the circadian expression pattern of orexin receptor type 2 (OX2R) and its potential effect on the feeding behavior of abalone, the coding region sequence of OX2R that is 1215 bp in length and encodes 404 amino acids was first cloned using the rapid amplification of cDNA ends technique. A recombinant expression vector was constructed for H. discus hannai based on the OX2R protein, obtaining a recombinant protein with a molecular weight of 46 kDa. Polyclonal antibody was prepared with the purified recombinant protein used as the antigen, and the antibody titer of ≥512 K was detected by enzyme-linked immunosorbent assay. The expression levels of OX2R determined using western blotting were highest in the intestinal tract (P < 0.05), but they were not significantly different from the levels in the pedal. Immunofluorescence experiments affirmed that OX2R was widely expressed in the columnar cells of the intestinal mucosal epithelium. To further account for the relationship between the onset of feeding behavior and the expression level of OX2R in abalone, the circadian expression characteristics of OX2R were analyzed by dissecting the intestinal tissues after three days of normal feeding and fasting and following the refeeding treatment. The expression levels of OX2R in the refeeding group were significantly higher than those in the normal feeding and fasting groups at any time point (P < 0.05). The cosine curve analysis revealed that the expression levels of OX2R lost rhythmicity after fasting. Based on the quantification of behavioral data for abalone after fasting and refeeding, the cumulative movement distance and movement duration in each group followed a significant cosine rhythm (P < 0.05), which is consistent with abalone's nocturnal ecological habits. However, the cumulative movement distance and movement duration in the fasting group were significantly lower than those in the normal feeding and refeeding groups (P < 0.05). The peak phases of the cumulative movement distance and movement duration in the refeeding group (ZT08:22 and ZT08:44) shifted backward compared to the normal feeding group (ZT07:33 and ZT07:39). The above results first identified the structural characteristics and circadian expression patterns of OX2R in the marine mollusk abalone, which may reveal the molecular mechanism behind the generation of a feeding rhythm in marine nocturnal organisms and serve as a tool helping to maintain the diversity of marine benthic resources.

Existence of circadian rhythm and its response behavior under different storage conditions of soybean sprouts

The circadian system plays an essential role in plant cells, and numerous physiological events are generally modulated by circadian clock genes. To further improve postharvest handling of fresh produce, it is vital to understanding the behavior of clock gene expression and its underlying interactions with changes in quality. In this study, the effect of temperature and controlled atmosphere storage on the expression of clock genes (GmLCL1, GmPRR7, GmGI, GmTOC1, and GmLUX), postharvest quality characteristics and their related genes in soybean sprouts were investigated. By fitting the obtained gene expression level using the qPCR method with the cosine curve equation, it was successfully found that the circadian rhythm existed under constant dark storage conditions of soybean sprouts. A significant rhythm in clock gene expression was observed in control soybean sprouts. In contrast, low temperature storage diminished the cyclic expression of GmLCL1, GmPRR7, and GmTOC1, which also affected GmGI and GmLUX expression. Additionally, high CO2 concentrations during storage disturbed the circadian clock by affecting the phase and amplitude of each gene; for low O2 concentrations, it was only affected by amplitude. Interestingly, low temperature, low O2, and high CO2 maintained postharvest quality, including reduced respiration, weight loss and browning incidence. The expression behaviors of postharvest quality attribute-related genes (GmFUM1, GmCS, Gm2-OGDH, GmPPO1, GmPAL) were also influenced by the storage treatments. Overall, the findings first suggest a possible link between clock disruption and postharvest quality maintenance of soybean sprouts.

Variability of Helioclimate Factors and Applicability to the Emergency Service Population of the Northern Region

The purpose of this study was to study the influence of the variability of weather and heliophysical factors on the appeal to the Ambulance service for different groups of nosologies in the population of the Russian North. Information about calls to the emergency medical service of Khanty-Mansiysk was obtained from the database of calls for the period from 2001 to 2021 by disease classes (ICD-10). To assess the dynamics of weather factors, data from the All-Russian Research Institute of Hydrometeorological Information and materials from the weather station of Khanty-Mansiysk were used. The dynamics of air temperature; barometric pressure; relative humidity; baric trend; maximum wind speed; weight oxygen content in the air are analyzed. Data on the relative daily number of sunspots are obtained from the materials of the Royal Observatory of Belgium. The average daily values of the level of planetary geomagnetic activity, expressed by the Ap index, are copied from the website of the National Center for Geophysical Data of the USA (Boulder). Mathematical processing was carried out using wavelet analysis. The graph of temperature fluctuations for the period from 2001 to 2021 shows a significant circadian cyclicity and a semi-annual rhythm with a high level of trend. Significant rhythms of barometric pressure with a period of 5 years, 1 year and rhythms close to semi-annual, seasonal and near-monthly are observed. Humidity changes significantly in the circadian and intra-annual rhythms. The baric tendency has significant rhythms: 3 years, 1 year, 6, 3, 2 months. Changes in the maximum wind speed do not have a circadian rhythm, but intra-annual monthly variations are observed. The value of the weight oxygen content has circadian; two-year, five-year; two- and near-monthly rhythms. The relative number of sunspots (W) for the period from 2001 to 2021 is characterized by a five-, two-year and circadian rhythm. When considering the variations of the number W for the period from 1818 to 2017, in addition to the classic eleven-year, annual and near-monthly, rhythms with a period of 42.5 years, 18.1 years and 2.1 years are found. The index of planetary geomagnetic activity (Ar) has a rhythm with a period of 4 years, two-year and near-annual. The significance of all rhythms is p=0.001. When analyzing fluctuations in geomagnetic activity from 1932 to 2016, long-term rhythms are added: 35.00 years; 16.06 years; 10.88 years; semi-annual and three-month rhythms. Despite numerous hypotheses of the search for cosmobiological harmony in the form of evolutionary synchronisms, rhythmic cascades, golden section, the problem of the interaction of exogenous natural rhythms and endogenous rhythms of the human body remains largely unresolved. Comparison of the results of various studies is difficult due to methodological and mathematical approaches. With observation periods of 100-200 years or more, a long-period component is monitored, and in clinical studies (from a day to a week), short-period components are detected. Changing the background in the form of helioclimatic and social variations also does not add accuracy. The use of various methods of time series analysis involves obtaining information of different resolution levels (Fourier transform, SWANN, wavelet analysis). Nevertheless, the results obtained track the classical rhythms of solar and geomagnetic activity with periods of about eleven years, a year and a month. There is also a 35-year-old rhythm, a 42.5-year-old rhythm close to the 44.16-year rhythm identified by Bezrukova A.Ya., at 18.1 years (long-period components of the lunar tide) and other intra-annual rhythms with periods from two weeks to 9 months. The effect of helioclimatic factors on human health indicates the absence of constant coherence (in our case, the consistency of these processes over time, manifested when they are combined), due to the presence of a large number of mega- and mesorhythms, which is manifested by amplitude and phase desynchronization of heliogeophysical indicators and health status.

Daily Rhythms in the IGF-1 System in the Liver of Goldfish and Their Synchronization to Light/Dark Cycle and Feeding Time.

The relevance of the insulin-like growth factor-1 (IGF-1) system in several physiological processes is well-known in vertebrates, although little information about their temporal organization is available. This work aims to investigate the possible rhythmicity of the different components of the IGF-1 system (igf-1, the igf1ra and igf1rb receptors and the paralogs of its binding proteins IGFBP1 and IGFBP2) in the liver of goldfish. In addition, we also study the influence of two environmental cues, the light/dark cycle and feeding time, as zeitgebers. The hepatic igf-1 expression showed a significant daily rhythm with the acrophase prior to feeding time, which seems to be strongly dependent on both zeitgebers. Only igfbp1a-b and igfbp1b-b paralogs exhibited a robust daily rhythm of expression in the liver that persists in fish held under constant darkness or randomly fed. The hepatic expression of the two receptor subtypes did not show daily rhythms in any of the experimental conditions. Altogether these results point to the igf-1, igfbp1a-b, and igfbp1b-b as clock-controlled genes, supporting their role as putative rhythmic outputs of the hepatic oscillator, and highlight the relevance of mealtime as an external cue for the 24-h rhythmic expression of the IGF-1 system in fish.

Artificial Dim Light at Night during Pregnancy Can Affect Hormonal and Metabolic Rhythms in Rat Offspring.

Artificial light at night (ALAN) is considered an environmental risk factor that can interfere with the circadian control of the endocrine system and metabolism. We studied the impact of ALAN during pregnancy on the hormonal and biochemical parameters in rat pups at postnatal (P) days P3, P10, and P20. Control dams (CTRL) were kept in a standard light-dark regime, and ALAN dams were exposed to dim ALAN (<2 lx) during the whole pregnancy. A plasma melatonin rhythm was found in all CTRL groups, whereas in ALAN pups, melatonin was not rhythmic at P3, and its amplitude was lowered at P10; no differences were found between groups at P20. Plasma corticosterone was rhythmic at P20 in both groups, with decreased mesor in ALAN pups. Plasma thyroid hormones exhibited an inconsistent developmental pattern, and vasopressin levels were suppressed at the beginning of the dark phase at P20 in ALAN compared to CTRL. Glucose and cholesterol showed significant daily rhythms in CTRL but not in ALAN offspring at P3. Exposure to ALAN during pregnancy disturbed the development of daily rhythms in measured hormones and metabolites, suggesting that ALAN during pregnancy can act as an endocrine disruptor that can interfere with the normal development of the progeny.

Genome-Wide Identification and Characterization of the CCT Gene Family in Foxtail Millet (Setaria italica) Response to Diurnal Rhythm and Abiotic Stress.

The CCT gene family plays important roles in diurnal rhythm and abiotic stress response, affecting crop growth and development, and thus yield. However, little information is available on the CCT family in foxtail millet (Setaria italica). In the present study, we identified 37 putative SiCCT genes from the foxtail millet genome. A phylogenetic tree was constructed from the predicted full-length SiCCT amino acid sequences, together with CCT proteins from rice and Arabidopsis as representatives of monocotyledonous and dicotyledonous plants, respectively. Based on the conserved structure and phylogenetic relationships, 13, 5, and 19 SiCCT proteins were classified in the COL, PRR, and CMF subfamilies, respectively. The gene structure and protein conserved motifs analysis exhibited highly similar compositions within the same subfamily. Whole-genome duplication analysis indicated that segmental duplication events played an important role in the expansion of the CCT gene family in foxtail millet. Analysis of transcriptome data showed that 16 SiCCT genes had significant diurnal rhythm oscillations. Under abiotic stress and exogenous hormonal treatment, the expression of many CMF subfamily genes was significantly changed. Especially after drought treatment, the expression of CMF subfamily genes except SiCCT32 was significantly up-regulated. This work provides valuable information for further study of the molecular mechanism of diurnal rhythm regulation, abiotic stress responses, and the identification of candidate genes for foxtail millet molecular breeding.

Diurnal rhythms of spontaneous intracranial high-frequency oscillations

ObjectiveSeizures are known to occur with diurnal and other rhythms. To gain insight into the neurophysiology of periodicity of seizures, we tested the hypothesis that intracranial high-frequency oscillations (HFOs) show diurnal rhythms and sleep-wake cycle variation. We further hypothesized that HFOs have different rhythms within and outside the seizure-onset zone (SOZ). MethodsIn drug-resistant epilepsy patients undergoing stereotactic-EEG (SEEG) monitoring to localize SOZ, we analyzed the number of 50-200 Hz HFOs/channel/minute (HFO density) through a 24-hour period. The distribution of HFO density during the 24-hour period as a function of the clock time was analyzed with cosinor model, and for non-uniformity with the sleep-wake cycle. ResultsHFO density showed a significant diurnal rhythm overall and both within and outside SOZ. This diurnal rhythm of HFO density showed significantly lower amplitude and longer acrophase within SOZ compared to outside SOZ. The peaks of difference in HFO density within and outside SOZ preceded the seizures by approximately 4 hours. The difference in HFO density within and outside SOZ also showed a non-uniform distribution as a function of sleep-wake cycle, with peaks at first hour after arousal and ±2 hours around sleep onset. ConclusionsOur study shows that the diurnal rhythm of intracranial HFOs is more robust outside the SOZ. This suggests cortical tissue within SOZ generates HFOs relatively more uniformly throughout the day with attenuation of expected diurnal rhythm. The difference in HFO density within and outside SOZ also showed non-uniform distribution according to clock times and the sleep-wake cycle, which can be a potential biomarker for preferential times of pathological cortical excitability. A temporal correlation with seizure occurrence further substantiates this hypothesis.

Inflammatory signalling in atrial cardiomyocytes: a novel unifying principle in atrial fibrillation pathophysiology.

Inflammation has been implicated in atrial fibrillation (AF), a very common and clinically significant cardiac rhythm disturbance, but its precise role remains poorly understood. Work performed over the past 5 years suggests that atrial cardiomyocytes have inflammatory signalling machinery — in particular, components of the NLRP3 (NACHT-, LRR- and pyrin domain-containing 3) inflammasome — that is activated in animal models and patients with AF. Furthermore, work in animal models suggests that NLRP3 inflammasome activation in atrial cardiomyocytes might be a sufficient and necessary condition for AF occurrence. In this Review, we evaluate the evidence for the role and pathophysiological significance of cardiomyocyte NLRP3 signalling in AF. We first summarize the evidence for a role of inflammation in AF and review the biochemical properties of the NLRP3 inflammasome, as defined primarily in studies of classic inflammation. We then briefly consider the broader evidence for a role of inflammatory signalling in heart disease, particularly conditions that predispose individuals to develop AF. We provide a detailed discussion of the available information about atrial cardiomyocyte NLRP3 inflammasome signalling in AF and related conditions and evaluate the possibility that similar signalling might be important in non-myocyte cardiac cells. We then review the evidence on the role of active resolution of inflammation and its potential importance in suppressing AF-related inflammatory signalling. Finally, we consider the therapeutic potential and broader implications of this new knowledge and highlight crucial questions to be addressed in future research.

In Situ Measurements of Plankton Biorhythms Using Submersible Holographic Camera

The paper presents a diagnostic complex for plankton studies using the miniDHC (digital holographic camera). Its capabilities to study the rhythmic processes in plankton ecosystems were demonstrated using the natural testing in Lake Baikal in summer. The results of in situ measurements of plankton to detect the synchronization of collective biological rhythms with medium parameters are presented and interpreted. The most significant rhythms in terms of the correlation of their parameters with medium factors are identified. The study shows that the correlation with water temperature at the mooring site has the greatest significance and reliability. The results are verified with biodiversity data obtained by the traditional mesh method. The experience and results of the study can be used for the construction of a stationary station to monitor the ecological state of the water area through the digitalization of plankton behavior.

Stressful Daylight: Differences in Diel Rhythmicity Between Albino and Pigmented Fish

In laboratory experiments, variously colored strains of animals, including those with albino phenotypes, are commonly used. The melanocortin theory suggests, however, that coloration phenotypes alter animal physiology and behavior. Animals with the albino phenotype show photoreceptor degradation associated with lowered visual accuracy, escape reactions, etc., presumably accompanied by prevailing nocturnal activity and lowered aggressiveness. This assumption was tested in small groups of albino and pigmented European catfish, Silurus glanis, during the diel cycle. The frequency of agonistic interactions was observed during mutual contests for shelters, and subsequently, blood plasma, brain, gill, and liver samples were collected to evaluate stress parameters. In an experimental arena with shelters, the light/dark rhythmicity of locomotor activity and aggressiveness of the two phenotypes were comparable; the peak was observed at night, and a lower peak was observed at dawn. In an experimental stream without shelters, the peak of locomotor activity occurred at night for only the pigmented phenotype. In the evaluation of 4 antioxidants and 1 oxidative stress indicator, representing a total of 15 indices, albino fish showed significant rhythmicity for 8 indices, whereas pigmented catfish showed significant rhythmicity for 5 indices. The production of blood stress parameters with the peak during the day occurred only in albino fish. A complex model was fitted with the aim of evaluating the links between behavioral and biochemical indices. Time periodicity was modeled using a sine wave and confirmed parallel courses of agonistic interactions in the catfish groups; the peak at dawn was associated with a 4.08-fold (conf. int. 3.53–4.7) increase in such interactions. The changes in glucose and superoxide dismutase concentrations varied with phenotype, while the effects of cortisol, lactate and catalase did not. In summary, the rhythmicity of locomotor activity and changes in the aggressiveness of catfish were influenced by shelter availability, and the effect of light-induced stress was more apparent in albino fish than in pigmented conspecific fish. The results suggested that laboratory-raised animals with pigmentation patterns naturally occurring in the wild show more reasonable values during experiments than those with an albino phenotype.