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Abstract Objective Flow cytometry (FC) is probably the most important technique for single-cell analysis. It’s precisely, rapid, and suitable for multidimensional single-cell analysis. The commonly used side scatter (SSC) intensity determined by FC is often interpreted as a measure of the internal cellular complexity of cells. In simple terms, the more structured a cell is, the higher the SSC intensity quantified by FC. Nevertheless, most of the studies that support this interpretation are based on data derived from animal or human cell lines and while it is assumed that the results can also be transferred to plant or algal cell lines, the details remain unclear. The objective of the recent work is to clarify the interpretation of the SSC signal from algal cells. Results Algal lipid droplets and their starch play an inherent role to shape the popular SSC signal derived from FC. This was shown by a theoretical approach based on Lorenz–Mie theory. These results were supported by experiments with different model cultures of Chlamydomonas reinhardtii in which a high linear correlation was observed between the SSC signal and the ‘physical’ starch quantity.

It is believed that some wavelengths of light penetrate through eggshell and are perceived by avian embryo, and may consequently affect rhythm establishment and development. This research aimed to explore the influence of prenatal light exposure on the morphological alterations of retinal tissue, the expression of visual developmental signaling systems (TGF-β/Smad pathway), the expression of clock related genes (cClock, cBmal1, cBmal2, cAanat), and melatonin concentration in the chicken embryonic retina. Layer eggs (Jingfen No.6) were subjected to white light (5000K, WL) and green light (520 nm/515-525 nm, GL) with a 12L:12D photoperiod throughout the entire incubation period, in contrast to no light incubation (NL). The results showed that the thickness of retina and each retinal lamina of chicken embryo in WL at E20 was much thicker than that of chicken embryo in GL (P < 0.05). In contrary, the expression level of TGF-β1 mRNA and Smad2/3 protein in retina was dramatically downregulated in WL when compared to that in NL and GL (P < 0.01). Furthermore, the incubation light simultaneously significantly affected the diurnal rhythms of the chicken embryonic retina. The expression of three clock genes (cBmal1/2, cClock) and cAanat exhibited significant diurnal rhythms in GL (P < 0.05). Additionally, green light stimulation significantly enhanced melatonin secretion but did not show diurnal rhythm. However, cBmal1, cAanat, and melatonin expression exhibited diurnal rhythms (P < 0.01), while the others did not in WL. In NL, only cBmal1 exhibited diurnal rhythmicity (P < 0.01). In conclusion, providing light of different wavelengths during the incubation process of poultry can have varying effects on embryonic visual development and the establishment of diurnal rhythms. WL had an advantage to GL and NL on retina development and diurnal rhythm through significantly influencing the expression of genes related to visual developmental signaling pathways and clock genes. A well-developed retina in WL exposure chicken embryo may be beneficial for establishing a melatonin rhythm. Conversely, the established circadian rhythm could improve embryonic development.

[ Objective ] As an important regulator involved in protein synthesis and gene expression , riboso- mal proteins are crucial for plant growth and development and stress response. In this study , a ribosomal protein family gene OsRPL36A was cloned from rice , and a preliminary study was performed for its bio- logical function , providing a basis for the study of OsRPL36A function. [ Methods ] Bioinformatics tech- niques were used to analysis gene structure , cis -regulatory elements , and evolution process of OsRPL36A . Meanwhile , the expression of OsRPL36A in different tissues and under diurnal rhythm , different hor- mones , and abiotic stresses were analyzed by quantitative real-time PCR ( qRT-PCR ) . [ Results ] ( 1 ) OsR- PL36A encoded 98 amino acids with a 297 bp coding region , which belonged to the ribosomal protein L36 supergene family , and was named as OsRPL36A . ( 2 ) The promoter region of OsRPL36A contained 3 rhythmic expression-related elements , 10 light-responsive elements , 14 hormone-responsive elements , and 27 environmental stress response elements. ( 3 ) The expression of OsRPL36A in leaves was relatively higher than that in other tissues and presented a typical rhythmic expression pattern. The expression of OsRPL36A was in- duced by IAA , high temperature , low temperature , osmotic stress , and so on. [ Conclusion ] OsRPL36A was highly expressed in leaves and presented a typical rhythmic expression pattern. OsRPL36A responded to IAA and might be involved in response to heat shock , low temperature , salt , and osmotic stresses.

Objectives: Salivary cortisol reflects the biologically active form of serum cortisol, offering a noninvasive evaluation method for the diurnal rhythm of the hypothalamic-pituitary-adrenal (HPA) axis. While liquid chromatography-tandem mass spectrometry (LC-MS/MS) is known for its specificity, immunoassays (IA) are commonly used because of their simplicity. This study aimed to assess the performance of salivary cortisol measurement using both IA and LC-MS/MS in comparison to serum-free cortisol measurement. Methods: Assay results for 188 saliva and 94 serum samples from 47 participants were analyzed. Salivary samples collected at different time points were analyzed using IA and LC-MS/MS. Serum samples were analyzed for cortisol, cortisol-binding globulin, and free cortisol. The statistical analyses included correlations and method comparisons. Results: The diurnal salivary cortisol profiles exhibited a comparable circadian rhythm pattern; however, the concentrations measured using IA were consistently higher than those measured using LC-MS/MS. The correlation analysis revealed robust associations among salivary cortisol (IA), salivary cortisol (LC-MS/MS), and serum-free cortisol levels (LC-MS/MS). However, the method comparison revealed a systematic bias between IA and LC-MS/MS in salivary cortisol measurement. Conclusions: This study contributes to the ongoing debate on assay techniques by affirming the suitability of IA and LC-MS/MS for salivary cortisol measurement to assess dynamic changes in HPA axis activity. The identified systematic bias emphasizes the importance of selecting methods based on specific research or clinical requirements.

Abstract Background One of the most prominent features of living organisms is their circadian rhythm, which governs a wide range of physiological processes and plays a critical role in maintaining optimal health and function in response to daily environmental changes. This work applied bibliometric analysis to explore quantitative and qualitative trends in circadian rhythm in cardiovascular diseases (CVD). It also aims to identify research hotspots and provide fresh suggestions for future research. Methods The Web of Science Core Collection was used to search the data on circadian rhythm in CVD. HistCite, CiteSpace, and VOSviewer were used for bibliometric analysis and visualization. The analysis included the overall distribution of yearly outputs, top nations, active institutions and authors, core journals, co-cited references, and keywords. To assess the quality and efficacy of publications, the total global citation score (TGCS) and total local citation score (TLCS) were calculated. Results There were 2102 papers found to be associated with the circadian rhythm in CVD, with the overall number of publications increasing year after year. The United States had the most research citations and was the most prolific country. Hermida RC, Young ME, and Ayala DE were the top three writers. The three most notable journals on the subject were Chronobiology International, Hypertension Research, and Hypertension. In the early years, the major emphasis of circadian rhythm in CVD was hormones. Inflammation, atherosclerosis, and myocardial infarction were the top developing research hotspots. Conclusion Circadian rhythm in CVD has recently received a lot of interest from the medical field. These topics, namely inflammation, atherosclerosis, and myocardial infarction, are critical areas of investigation for understanding the role of circadian rhythm in CVD. Although they may not be future research priorities, they remain of significant importance. In addition, how to implement these chronotherapy theories in clinical practice will depend on additional clinical trials to get sufficient trustworthy clinical evidence.

Diurnal rhythms in physiological functions contribute to homeostasis in many organisms. Although relationships between molecular biology and diurnal rhythms have been well studied in model organisms like higher plants, those in harmful algal bloom species are poorly understood. Here we measured several physiological parameters and the expression patterns of photosynthesis-related and antioxidant-enzyme genes in the Chattonella marina complex to understand the biological meaning of diurnal rhythm. Under a light–dark cycle, Fv/Fm and expression of psbA, psbD, and 2-Cys prx showed significant increases in the light and decreases during the dark. These rhythms remained even under continuous dark conditions. DCMU suppressed the induction of psbA, psbD, and 2-Cys prx expression under both light regimes. Oxidative stress levels and H2O2 scavenging activities were relatively stable, and there was no significant correlation between H2O2 scavenging activities and antioxidant-enzyme gene expression. These results indicate that the Chattonella marina complex has developed mechanisms for efficient photosynthetic energy production in the light. Our results showed that this species has a diurnal rhythm and a biological clock. These phenomena are thought to contribute to the efficiency of physiological activities centered on photosynthesis and cell growth related to the diurnal vertical movement of this species.

Background: Night shift work is associated with sleep disturbances, obesity, and cardiometabolic diseases. Disruption of the circadian clock system has been suggested to be an independent cause of type 2 diabetes and cardiovascular disease in shift workers. We aimed to improve alignment of circadian timing with social and environmental factors with administration of melatonin. Methods: In a randomized, placebo-controlled, prospective study, we analysed the effects of 2 mg of sustained-release melatonin versus placebo on glucose tolerance, insulin resistance indices, sleep quality, circadian profiles of plasma melatonin and cortisol, and diurnal blood pressure profiles in 24 rotating night shift workers during 12 weeks of treatment, followed by 12 weeks of wash-out. In a novel design, the time of melatonin administration (at night or in the morning) depended upon the shift schedule. We also compared the baseline profiles of the night shift (NS) workers with 12 healthy non-night shift (NNS)-working controls. Results: We found significantly impaired indices of insulin resistance at baseline in NS versus NNS (p

Abstract The quantitative control of FLOWERING LOCUS T (FT) activation is important for the floral transition in flowering plants. However, the flowering regulation mechanisms in the day-neutral, summer-flowering chrysanthemum plant remain unclear. In this study, the chrysanthemum BBX7 homolog CmBBX7 was isolated and its flowering function was identified. The expression of CmBBX7 showed a diurnal rhythm and CmBBX7 exhibited higher expression levels than CmBBX8. Overexpression of CmBBX7 in transgenic chrysanthemum accelerated flowering, whereas lines transfected with a chimeric repressor (pSRDX-CmBBX7) exhibited delayed flowering. Yeast single hybridization, luciferase, electrophoretic mobility shift, and chromatin immunoprecipitation assays showed that CmBBX7 directly targets CmFTL1. In addition, we found that CmBBX7 and CmBBX8 interact to positively regulate the expression of CmFTL1 through binding to its promoter. Collectively, these results highlight CmBBX7 as a key cooperator in the BBX8–FT module to control chrysanthemum flowering. Graphical Abstract

The human gut microbiome has primarily been studied through the use of fecal samples, a practice that has generated vital knowledge on the composition and functional capacities of gastrointestinal microbial communities. However, this reliance on fecal materials limits the investigation of microbial dynamics in other locations along the gastrointestinal tract (in situ), and the infrequent availability of fecal samples prevents analysis at finer temporal scales (e.g., hours). In our study, we utilized colonic transendoscopic enteral tubing, a technology originally developed for fecal microbiota transplantation, to sample the ileocecal microbiome twice daily; metagenomic and metatranscriptomic analyses were then conducted on these samples. A total of 43 ileocecal and 28 urine and fecal samples were collected from five healthy volunteers. The ileocecal and fecal microbiomes, as profiled in the five volunteers, were found to be similar in metagenomic profiling, yet their active genes (metatranscriptome) were found to be highly distinct. Both microbiomes were perturbed after laxative exposure; over time, they exhibited reduced dissimilarity to their pre-treatment state, thereby demonstrating resilience as an innate property of the gut microbiome, although they did not fully recover within our observation time window. Sampling of the ileocecal microbiome during the day and at night revealed the existence of diurnal rhythms in a series of bacterial species and functional pathways, particularly those related to short-chain fatty acid production, such as Propionibacterium acnes and coenzyme A biosynthesis II. Autocorrelation analysis and fluctuations decomposition further indicated the significant periodicity of the diurnal oscillations. Metabolomic profiling in the fecal and urine samples mirrored the perturbance and recovery in the gut microbiome, indicating the crucial contribution of the gut microbiome to many key metabolites involved in host health. This study provides novel insights into the human gut microbiome and its inner resilience and diurnal rhythms, as well as the potential consequences of these to the host.

Melatonin, a neurohormone nocturnally produced by the pineal gland, is known to regulate the circadian rhythm. It has been recently reported that variants of melatonin receptors are associated with an increased risk of hyperglycemia and type 2 diabetes, suggesting that melatonin may be involved in the regulation of glucose homeostasis. Insulin is a key hormone that regulates circulating glucose levels and cellular metabolism after food intake in many tissues, including the brain. Although cells actively uptake glucose even during sleep and without food, little is known regarding the physiological effects of nocturnal melatonin on glucose homeostasis. Therefore, we presume the involvement of melatonin in the diurnal rhythm of glucose metabolism, independent of insulin action after food intake. In the present study, goldfish (Carassius auratus) was used as an animal model, since this species has no insulin-dependent glucose transporter type 4 (GLUT4). We found that in fasted individuals, plasma melatonin levels were significantly higher and insulin levels were significantly lower during the night. Furthermore, glucose uptake in the brain, liver, and muscle tissues also significantly increased at night. After intraperitoneal administration of melatonin, glucose uptake by the brain and liver showed significantly greater increases than in the control group. The administration of melatonin also significantly decreased plasma glucose levels in hyperglycemic goldfish, but failed to alter insulin mRNA expression in Brockmann body and plasma insulin levels. Using an insulin-free medium, we demonstrated that melatonin treatment increased glucose uptake in a dose-dependent manner in primary cell cultures of goldfish brain and liver cells. Moreover, the addition of a melatonin receptor antagonist decreased glucose uptake in hepatocytes, but not in brain cells. Next, treatment with N1-acetyl-5-methoxykynuramine (AMK), a melatonin metabolite in the brain, directly increased glucose uptake in cultured brain cells. Taken together, these findings suggest that melatonin is a possible circadian regulator of glucose homeostasis, whereas insulin acquires its effect on glucose metabolism following food intake.

Asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) interfere with nitric oxide (NO) formation from L-arginine via different mechanisms. ADMA is a biomarker of cardiovascular disease and mortality, whilst SDMA is a biomarker of mortality after ischemic stroke. Homoarginine, another L-arginine-derived amino acid, is associated with stroke and congestive heart failure. Acute ischemic events like myocardial infarction show a time-of-day variation in the timing of their onset, as do NO-mediated vascular function and blood pressure. We studied whether the plasma concentrations of L-arginine-related amino acid metabolites show diurnal variation in a clinical study comparing 12 non-night shift workers with 60 rotating night shift workers. The plasma concentrations of L-arginine-related biomarkers, melatonin, and cortisol were measured every 3 h during a 24-h period. In addition, 24-h blood pressure recordings were performed. In non-night shift workers, L-arginine and homoarginine plasma concentrations showed diurnal variation with a 12-h period, which were both attenuated in night shift workers. ADMA and SDMA showed a 24-h rhythmicity with no significant differences in phase between night shift and non-night shift workers. The plasma profiles of melatonin and cortisol were not significantly different between both groups, suggesting that the rotating night shift work does not have a major influence on central suprachiasmatic nuclei clock timing. In addition, systolic and diastolic blood pressure patterns were similar between both groups. Our data show diurnal variation of dimethylarginines with the timing of their acrophases corresponding to the published timing of the peak incidence of cardiac ischemic events.

Diurnal oscillation persists throughout the body and plays an essential role in maintaining physiological homeostasis. Disruption of diurnal rhythm contributes to many diseases including type 2 diabetes. The regulatory mechanism of the transcription-translation feedback loop (TTFL) of core clock genes is well-established, while a systematic study across all regulatory layers of gene expression, including gene transcription, RNA translation, and DNA binding protein (DBP) activities, is still lacking. We comprehensively bioinformatics analyzed the rhythmicity of gene transcription, mature RNA abundance, protein abundance and DBP activity using publicly available omic-datasets from mouse livers. We found that the core clock genes, Bmal1 and Rev-erbα, persistently retained rhythmicity in all stages, which supported the essential rhythmic function along with the TTFL. Interestingly, there were many layer-specific rhythmic genes playing layer-specific rhythmic functions. The systematic analysis of gene transcription rate, RNA translation efficiency, and post-translation modification of DBP were incorporated to determine the potential mechanisms for layer-specific rhythmic genes. We observed the gene with rhythmic expression in both mature RNA and protein layers were largely due to relatively consistent translation rate. In addition, rhythmic translation rate induced the rhythms of protein whose mature RNA levels were not rhythmic. Further analysis revealed a phosphorylation-mediated and an enhancer RNA-mediated cycling regulation between the corresponding layers. This study presents a global view of the oscillating genes in multiple layers via a systematical analysis and indicates the complexity of regulatory mechanisms across different layers for further functional study.

Background: People are divided into different chronotypes in relation to their circadian rhythm features. The Morningness–Eveningness Questionnaire (MEQ), developed by Horne and Östberg, was the first and is the most used questionnaire for determining the chronotype of people. The reliability and validity of MEQ were tested in this study due to some deficiencies and inconsistencies in previous reliability and validity studies for the Turkish versions of MEQ and deficiencies regarding the validity and reliability of other versions of MEQ. Subjects and Methods: MEQ was translated into Turkish based on the opinions of five academics who were experts in their respective fields and the suitability and content validity of the questionnaire were ensured. The Turkish MEQ was administered to 419 undergraduate students aged 18–34 years. Robust minimum rank factor analysis (MRFA) was used to reveal the construct validity of the questionnaire. Results: As a result of the analyses, the questionnaire was examined in three factors. None of the items were excluded from the study and all items were collected under three factors. The explained total variance value was 42.7%, and the factors explained 64% of common (shared) variance in MRFA. According to the reliability analysis, Cronbach's alpha value for the MEQ Turkish version was satisfactory for the overall questionnaire (0.765). Conclusions: The MEQ version developed in this study is more valid and reliable compared with other versions. However, these results support that a more detailed instrument for morningness and eveningness can be developed.

Several studies have been conducted focusing on antioxidant capacity of medicinal plants; however information is lacking on the daily rhythm of antioxidant capacity as well as photochemical reactions in medicinal plants under natural conditions. Thus, in this study, changes in phenolic acids, PSII functioning and antioxidant enzymes activities in response to low (1,100 m) and high (2,200 m) elevation sites in Marrubium vulgare L. were investigated. Plants were harvested and analyzed in a temporal manner; and for the latter analysis, leaf samples were frozen immediately in liquid N2 and stored in it until assay. High-altitude plants exhibited higher phenolics and carotenoids than that in low-altitude plants, which was associated with higher phenylalanine ammonia-lyase (PAL) activity. Results indicated that the absolute amounts of antioxidant enzymes activities were considerably greater in high-altitude plants than low-altitude plants. High-altitude plants showed the rapidly reversible inhibition of PSII reaction centers (dynamic photoinhibition) associated with an increase in non-photochemical rate constant (kN), which was important photoprotection mechanism under high-mountain conditions. Surprisingly, the activities of antioxidative enzymes, the accumulation of hydrogen peroxide (H2O2), & the free radical scavenging activities using DPPH radical-scavenging in the leaves of high-altitude plants showed diurnal rhythm during the course of day. Finally, we found that the ability of dynamic photoinhibition was an important photoprotection process during periods of high solar radiation in the high-altitude Marrubium vulgare plants.

Abstract Aim Soluble suppression of tumorigenicity‐2 (sST2) is a strong prognostic biomarker in heart failure. The emerging understanding of circadian biology in cardiovascular disease may lead to novel applications in prognosis and diagnosis and may provide insight into mechanistic aspects of the disease–biomarker interaction. So far, it is unknown whether sST2 exhibits a diurnal rhythm. Repeated measurements of sST2 may aid in clinical decision making. The goal of this study was to investigate whether sST2 exhibits diurnal variation in patients with heart failure with reduced ejection fraction (HFrEF) and in control subjects, thereby enhancing its diagnostic and prognostic values. Methods and results The study comprised 32 subjects: 16 HFrEF patients and 16 controls. Blood was collected at seven subsequent time points during a 24 h time period. sST2, N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP), melatonin, and cortisol were measured from serum. Peak values of sST2 clustered at daytime (modal value: 5 p.m.) in 87.6% of all subjects (81.3% of patients, P = 0.021; 93.8% of controls, P = 0.001), and minimum concentrations at night‐time (modal value: 5 a.m.) in 84.4% (87.5% of patients, P = 0.004 81.3% of controls, P = 0.021). A cosinor analysis of mean normalized sST2 values revealed significant cosine shaped 24 h oscillations of patients (P = 0.026) and controls (P = 0.037). NT‐proBNP in contrast did not show a diurnal rhythm, while melatonin and cortisol patterns were intact in all subjects. Conclusions sST2 exhibits a diurnal rhythm with lower values in the morning than in the late afternoon. This new insight could lead to refinement of its diagnostic and prognostic values through specified and consistent sampling times with repeated measurements. For example, by measuring sST2 during the afternoon, when levels are at their highest, false negatives on prognosis prediction could be avoided.

Abstract Background Based on the peak expression times during infection, early, middle, and late genes have been characterized in viruses (cyanophages) that infect the unicellular cyanobacterium Prochlorococcus. Laboratory experiments show that some cyanophages can only replicate in the light and thus exhibit diurnal infection rhythms under light-dark cycles. Field evidence also suggests synchronized infection of Prochlorococcus by cyanophages in the oceans, which should result in progressive expression of cyanophage early, middle, and late genes. However, distinct temporal expression patterns have not been observed in cyanophage field populations. Results In this study, we reanalyzed a previous metatranscriptomic dataset collected in the North Pacific Subtropical Gyre. In this dataset, it was previously shown that aggregate transcripts from cyanophage scaffolds display diurnal transcriptional rhythms with transcript abundances decreasing at night. By mapping metatranscriptomic reads to individual viral genes, we identified periodically expressed genes from putative viruses infecting the cyanobacteria Prochlorococcus and Synechococcus, heterotrophic bacteria, and algae. Of the 41 cyanophage genes, 35 were from cyanomyoviruses. We grouped the periodically expressed cyanomyovirus genes into early, middle, and late genes based on the conserved temporal expression patterns of their orthologs in cyanomyovirus laboratory cultures. We found that the peak expression times of late genes in cyanophage field populations were significantly later than those of early and middle genes, which were similar to the temporal expression patterns of synchronized cyanophage laboratory cultures. Conclusions The significantly later peak expression times of late genes in cyanomyovirus field populations suggest that cyanophage infection of Prochlorococcus is synchronized in the North Pacific Subtropical Gyre. The night-time peak expression of late genes also suggests synchronized lysis of Prochlorococcus at night, which might result in synchronized release of dissolved organic matter to the marine food web. Video abstract.

The biological variation of cardiac troponins and the existence of a circadian/diurnal rhythm have been poorly evaluated as only the recently developed high-sensitivity assays (hs-cTn) allow the detection of circulating concentrations of both cardiac troponin I (cTnI) and T (cTnT) in reference subjects and under the cut-off values. Available data seem to demonstrate a circadian rhythm for cTnT but not for cTnI but these data need to be confirmed and in particular it should be better clarified if possible variation may affect currently recommended rapid diagnostic algorithms for safe rule-in and rule-out strategies. Here we report the results obtained using a hs-cTnI assay in 35 subjects who underwent serial samples collection over time.

The circadian misalignment of the gut microbiota caused by unusual eating times in adult animals is related to disease development. However, whether the composition and diurnal rhythm of gut microbiota can be optimized by synchronizing the window period of eating with natural eating habits to reduce the risk of diarrhea remains unclear, especially in growing animals. In this study, 108 5-week-old weaned rabbits (nocturnal animals) were randomly subjected to daytime feeding (DF) and night-restricted feeding (NRF). At age 12 weeks, six rabbits were selected from each group, and caecum and cecal contents, as well as serum samples were collected at 4-h intervals during 24 h. Overall, NRF was found to reduce the risk of diarrhea in growing rabbits, improved the diurnal rhythm and abundance of beneficial microorganisms, along with the production of beneficial metabolites, whereas reduced the abundance of potential pathogens (Synergistes, Desulfovibrio, and Alistipes). Moreover, NRF improved diurnal rhythm of tryptophan hydroxylase isoform 1 and serotonin. Furthermore, NRF strengthened the diurnal amplitude of body core temperature, and promoted the diurnal expression of intestinal clock genes (BMAL1, CLOCK, REV-ERBα, and PER1), and genes related to the regulation of the intestinal barrier (CLAUDIN-1), and intestinal epithelial cell self-proliferation and renewal (BMI1). In vitro simulation experiments further revealed that synchronization of microbial-driven serotonin rhythm and eating activity-driven body temperature oscillations, which are important zeitgebers, could promote the diurnal expression of clock genes and CLAUDIN-1 in rabbit intestinal epithelial cells (RIEC), and enhance RIEC proliferation. This is the first study to reveal that NRF reprograms the diurnal rhythm of the gut microbiome, promotes the diurnal expression of clock genes and tight junction genes via synchronization of microbial-driven serotonin rhythm and eating activity-driven body temperature oscillations, thereby improving intestinal health and reducing the risk of diarrhea in growing rabbits. Collectively, these results provide a new perspective for the healthy feeding and management of growing animals.

Advances in tag technology now make it possible to monitor the behavior of small groups of individual fish as bioindicators of population wellbeing in commercial aquaculture settings. For example, tags may detect unusual patterns in fish heart rate, which could serve as an early indicator of whether fish health or welfare is becoming compromised. Here, we investigated the use of commercially available heart rate biologgers implanted into 24 Atlantic salmon weighing 3.6 ± 0.8 kg (mean ± SD) to monitor fish over 5 months in a standard 12 m × 12 m square sea cage containing ∼6,000 conspecifics. Post tagging, fish established a diurnal heart rate rhythm within 24 h, which stabilized after 4 days. Whilst the registered tagged fish mortality over the trial period was 0%, only 75% of tagged fish were recaptured at harvest, resulting in an unexplained tag loss rate of 25%. After 5 months, tagged fish were approximately 20% lighter and 8% shorter, but of the similar condition when compared to untagged fish. Distinct diurnal heart rate patterns were observed and changed with seasonal day length of natural illumination. Fish exhibited lower heart rates at night [winter 39 ± 0.2 beats per min (bpm), spring 37 ± 0.2 bpm, summer 43 ± 0.3 bpm, mean ± SE] than during the day (winter 50 ± 0.3 bpm, spring 48 ± 0.2 bpm, summer 49 ± 0.2 bpm) with the difference between night and day heart rates near half during the summer (6 bpm) compared to winter and spring (both 11 bpm). When fish experienced moderate and severe crowding events in early summer, the highest hourly heart rates reached 60 ± 2.5 bpm and 72 ± 2.4 bpm, respectively, on the day of crowding. Here, if the negative sublethal effects on fish that carry tags (e.g., growth rate) can be substantially reduced, the ability to monitor diurnal heart rate patterns across seasons and detect changes during crowding events, and using heart rate biologgers could be a useful warning mechanism for detecting sudden changes in fish behavior in sea cages.

The high laying performance of today’s laying hens places enormous demands on their mineral metabolism. While up-to-date data are rare, the present study aimed to describe blood parameters associated with egg laying and bone metabolism during the pre-laying period, in the course of the laying period and the daily egg laying cycle. Ten to 15 laying hens of two high-performing, phylogenetically divergent lines (BLA: brown-egg layer; WLA: white-egg layer), kept in single cages were blood sampled at 17, 25, 29, 49, and 69 weeks of age. Sampling was made at 6 a.m., 10 a.m., 2 p.m. and, with the exception of week 17, 6 p.m. Blood samples were analyzed for concentrations of total and ionized calcium, inorganic phosphate (PO4), markers of bone formation (osteocalcin) and resorption [carboxyterminal crosslinked telopeptide of type I collagen (CTX-I)], 25-hydroxycholecalciferol (25(OH)D3) and estradiol-17β. In the pre-laying period (17 week), the estradiol-17β level calculated for WLA was more than twice as high as the level calculated for BLA, while no significant difference could be observed in the laying period (25 to 69 weeks). BLA hens had significantly higher total calcium concentrations at 49 weeks of age as well as up to twice as high levels of osteocalcin and 25(OH)D3 than WLA at any time of the day from 25 to 69 weeks of age. While osteocalcin, CTX-I and 25(OH)D3 concentrations were significantly higher before the onset of lay, total calcium and estradiol-17β levels significantly increased from 17 to 69 weeks of age. In contrast, PO4 values varied only slightly during the experimental period and ionized calcium was highest at 17 and 49 weeks of age and lowest around peak production (29 week). In the course of the daily egg laying cycle blood concentrations clearly reflected the stage of egg formation. Our results provide up-to-date data of bone- and egg laying-associated blood parameters of two contemporary purebred layer lines over the course of the pre- and egg-laying period and the daily egg laying cycle. Differences between brown- and white-egg layers raise questions, whether phylogenetic background determines their efficiency to cope with high calcium demands relating to egg production.

AimsAcid phosphatase (APase) secretion by roots allows plants to mobilize organic phosphorus (P) in low P soils. However, the spatiotemporal dynamics of soil APase activity in response to P-rich patches remain unclear.MethodsHere, we grew maize in rhizoboxes with two contrasting soil types and different localized P supplies. In situ soil zymography was applied to examine the spatial-temporal variation of APase activity.ResultsWe found P-rich patches can induce the secretion of APase from roots, indicating that even mineral P fertilizers were localized apply, mobilization of soil organic P by roots can also be enhanced; APase hotspot areas and APase activities in the rhizosphere and bulk soil of the same rhizobox showed opposite diurnal rhythms across the whole soil profile. The APase hotspot area was 10–140% larger at noon than at midnight in the rhizosphere, which is consistent with the diurnal rhythm of photosynthesis. In contrast, in bulk soil, the area was 18–200% larger at midnight than at noon, which led to spatiotemporal niche differentiation with regard to the utilization of soil organic P; this alleviated competition between plants and soil microorganisms.ConclusionOur findings showed that APase secretion of roots was plastic in P-rich patches and showed an opposite diurnal rhythm with soil microorganisms in bulk soil.

Significant differences in salivary microbiota communities between polycystic ovary syndrome (PCOS) patients and healthy controls have been reported, and interestingly, some salivary microbiota exhibit diurnal oscillation in healthy people. However, whether the diurnal oscillation of salivary microbiota is present in PCOS patients is unknown. In this study, we describe the differences in the saliva microbiome between the PCOS group and the control group at different time points over 24 h. 16S rRNA gene amplicon sequencing was performed on salivary and fecal samples from 10 PCOS patients and 10 healthy controls, and salivary samples were collected at 6-h intervals over 24 h (Zeitgeber (ZT)0, ZT6, ZT12, and ZT18). Among the salivary samples, those from the PCOS group showed significant differences from those of the control group at each time point. Differences were evident in taxa level and metabolic pathways. Interestingly, we found that PCOS disrupted the diurnal rhythm of the salivary microbiota abundance, as determined in the group of healthy women. In addition, no similar changes were found in PCOS patients and controls between the oral and fecal microbiota, including differential microbiota at the phylum level. In this study, significant differences in the composition of the salivary microbiota between PCOS and healthy women were detected at different time points. We also showed that the diurnal rhythm of relative abundance of the salivary microbiota was disrupted in patients with PCOS, which might be related to development of oral-related diseases and systematic metabolic disorders.

Despite the increased survival opportunities for extremely preterm infants, their long-term cognitive outcomes remain poor, with increased incidence of cognitive impairments in childhood and reduced opportunities to attend higher education in young adulthood compared to their term-born peers. Given that a considerable fraction of preterm infants develop cognitive impairments even without apparent sentinel events at birth and cerebral lesions on MRI assessed at term equivalent age, future strategies to improve the outcome may need to address cerebral dysfunction, which cannot be explained by the classical understanding of the injury cascade triggered by hypoxia-ischaemia around birth. Developmental care has been proposed to minimize neurodevelopmental impairments related to preterm birth. However, considerable modes of cares, environmental settings and procedures provided by the developmental care of current style appear to offer little benefit to the sound development of infants. Although it is obvious that advanced life support and neuroprotective treatments fall far short in compensating for the burden of preterm birth, researchers need to make further effort to fill the knowledge gap in the cerebral function of foetuses and newborn infants before establishing evidence-based developmental care. Clinicians need to develop an ability to translate the findings from basic and translational studies incorporating their potential biases and limitations. Care for newborn infants needs to be reassessed, including but not limited to developmental care, in the context that any sensory input and motor reaction of preterm infants may ultimately affect their cognitive functioning.

ABSTRACT Prochlorococcus cyanobacteria grow in diurnal rhythms driven by diel cycles. Their ecology depends on light, nutrients, and top-down mortality processes, including lysis by viruses. Cyanophage, viruses that infect cyanobacteria, are also impacted by light. For example, the extracellular viability and intracellular infection kinetics of some cyanophage vary between light and dark conditions. Nonetheless, it remains unclear whether light-dependent viral life history traits scale up to influence population-level dynamics. Here, we examined the impact of diel forcing on both cellular- and population-scale dynamics in multiple Prochlorococcus-phage systems. To do so, we developed a light-driven population model, including both cellular growth and viral infection dynamics. We then tested the model against measurements of experimental infection dynamics with diel forcing to examine the extent to which population level changes in both viral and host abundances could be explained by light-dependent life history traits. Model-data integration reveals that light-dependent adsorption can improve fits to population dynamics for some virus-host pairs. However, light-dependent variation alone does not fully explain realized host and virus population dynamics. Instead, we show evidence consistent with lysis saturation at relatively high virus-to-cell ratios. Altogether, our study represents a quantitative approach to integrate mechanistic models to reconcile Prochlorococcus-virus dynamics spanning cellular-to-population scales. IMPORTANCE The cyanobacterium Prochlorococcus is an essential member of global ocean ecosystems. Light rhythms drive Prochlorococcus photosynthesis, ecology, and interactions with potentially lethal viruses. At present, the impact of light on Prochlorococcus-virus interactions is not well understood. Here, we analyzed Prochlorococcus and virus population dynamics with a light-driven population model and compared our results with experimental data. Our approach revealed that light profoundly drives both cellular- and population-level dynamics for some host-virus systems. However, we also found that additional mechanisms, including lysis saturation, are required to explain observed host-virus dynamics at the population scale. This study provides the basis for future work to understand the intertwined fates of Prochlorococcus and associated viruses in the surface ocean.

Circadian clock is usually involved in many physiological processes of plants, including responses to abiotic stress, whilst pseudo-response regulator 7 (PRR7) gene is the main component of the circadian clock. In this study, the cDNA of the PRR7 gene was obtained from trifoliate orange (Poncirus trifoliata). Based on the sequence analysis, the PtPRR7 gene had an open reading frame of 2343 bp, encoded 780 amino acids, and contained proteins of the REC and CCT domains. Subcellular localization indicated that PtPRR7 was mainly localized in the nucleus and a small amount of cytoplasm. qRT-PCR analysis revealed the highest expression level of PtPRR7 in roots than in both shoots and leaves. The PtPRR7 gene during 24 hours of soil water deficit exhibited a circadian rhythmic expression pattern: the expression peak at 9:00 am in leaves and at 21:00 pm in roots. Drought treatment affected PtPRR7 gene expression. Such data provide important references for understanding the characteristics of PtPRR7 gene in citrus plants.

ObjectiveTeachers are affected by high levels of job stress, leading to one of the highest rates of burnout. The purpose of our pilot study was to investigate the diurnal course of teachers’ psychological and physiological stress responses [cortisol levels, alpha-amylase, heart rate (HR), and heart rate variability (HRV)]. Another aim of the project was to test the applicability of ambulatory assessment methods in daily teaching situations.MethodsIn a non-clinical sample of eight primary school teachers (mean age = 43, SD = 15.22, 6 females) in Switzerland, continuous biopsychological data on two workdays and a free day were assessed. The teachers’ HRs and HRV were measured continuously using an ambulatory ECG. Additionally, eight saliva samples were collected from the teachers repeatedly throughout the day to determine the diurnal course of salivary cortisol and alpha-amylase (sAA). Perceived stress and anger ratings were assessed simultaneously.ResultsAs hypothesized, the teachers’ morning cortisol levels, perceived stress, and anger levels were significantly higher, and their overall HRV was significantly lower on workdays than on a free day. Conversely, sAA levels and HRs showed no significant differences between working and free days. Salivary markers exhibited the expected diurnal course, with decreasing cortisol and increasing sAA levels over the course of the day, while self-rated stress reached the maximum at midday during working days.ConclusionThe results of the present explorative study show that physiological and psychological parameters differ within working and free days for teachers. A comparison between working and free days resulted in differences in morning cortisol levels, HRV as well as stress and anger levels. The ambulatory assessment method was found to be applicable in daily teaching situations.

Flavonoids are favored compounds in plant responses to UV exposure and act in UV absorption and antioxidant activity. Here, it was investigated, with okra as a model species, how fast plants can react to changing UV conditions and to what extent these reactions take place. Okra (Abelmoschus esculentus) plants were exposed to either full or nearly no UV radiation. The diurnal rhythm of the plants was driven by the UV radiation and showed up to a 50% increase of the flavonoid content (measured optically in the +UV plants). This was reflected only in the trends in UV-absorption and antioxidant activity of the extracts but not in the soluble flavonoid glycosides and hydroxycinnamic acid derivatives. In a second experiment, a transfer from a −UV to a +UV condition at 9:00 CDT showed the immediate start of the diurnal rhythm, while this did not occur if the transfer occurred later in the day; these plants only started a diurnal rhythm the following day. After an adaptation period of seven days, clear differences between the +UV and -UV plants could be found in all parameters, whereas plants transferred to the opposite UV condition settle between the +UV and -UV plants in all parameters. Broadly, it can be seen that the flavonoid contents and associated functions in the plant are subject to considerable changes within one day and within several days due to the UV conditions and that this can have a considerable impact on the quality of plant foods.

Abstract Background Animal research suggests that neural reward activation may be systematically modulated by sleep and circadian function. Whether humans also exhibit sleep and circadian modulation of neural reward pathways is unclear. This area is in need of further research, as it has implications for the involvement of sleep and circadian function in reward-related disorders. The aim of this paper is to describe the protocol for a pair of systematic literature reviews to synthesise existing literature related to (1) sleep and (2) circadian modulation of neural reward pathways in healthy human populations. Methods A systematic review of relevant online databases (Scopus, PubMed, Web of Science, ProQuest, PsycINFO and EBSCOhost) will be conducted. Reference lists, relevant reviews and supplementary data will be searched for additional articles. Articles will be included if (a) they contain a sleep- or circadian-related predictor variable with a neural reward outcome variable, (b) use a functional magnetic resonance imaging protocol and (c) use human samples. Articles will be excluded if study participants had disorders known to affect the reward system. The articles will be screened by two independent authors. Two authors will complete the data extraction form, with two authors independently completing the quality assessment tool for the selected articles, with a consensus reached with a third author if needed. Narrative synthesis methods will be used to analyse the data. Discussion The findings from this pair of systematic literature reviews will assist in the identification of the pathways involved in the sleep and circadian function modulation of neural reward in healthy individuals, with implications for disorders characterised by dysregulation in sleep, circadian rhythms and reward function. Systematic review registration PROSPERO CRD42017064994

Abstract Background The circadian clock regulates plant metabolic functions and is an important component in plant health and productivity. Rhizosphere bacteria play critical roles in plant growth, health, and development and are shaped primarily by soil communities. Using Illumina next-generation sequencing and high-resolution mass spectrometry, we characterized bacterial communities of wild-type (Col-0) Arabidopsis thaliana and an acyclic line (OX34) ectopically expressing the circadian clock-associated cca1 transcription factor, relative to a soil control, to determine how cycling dynamics affected the microbial community. Microbial communities associated with Brachypodium distachyon (BD21) were also evaluated. Results Significantly different bacterial community structures (P = 0.031) were observed in the rhizosphere of wild-type plants between light and dark cycle samples. Furthermore, 13% of the community showed cycling, with abundances of several families, including Burkholderiaceae, Rhodospirillaceae, Planctomycetaceae, and Gaiellaceae, exhibiting fluctuation in abundances relative to the light cycle. However, limited-to-no cycling was observed in the acyclic CCAox34 line or in soil controls. Significant cycling was also observed, to a lesser extent, in Brachypodium. Functional gene inference revealed that genes involved in carbohydrate metabolism were likely more abundant in near-dawn, dark samples. Additionally, the composition of organic matter in the rhizosphere showed a significant variation between dark and light cycles. Conclusions The results of this study suggest that the rhizosphere bacterial community is regulated, to some extent, by the circadian clock and is likely influenced by, and exerts influences, on plant metabolism and productivity. The timing of bacterial cycling in relation to that of Arabidopsis further suggests that diurnal dynamics influence plant-microbe carbon metabolism and exchange. Equally important, our results suggest that previous studies done without relevance to time of day may need to be reevaluated with regard to the impact of diurnal cycles on the rhizosphere microbial community.

We investigated the effect of supplemental LED inter-lighting (80% red, 20% blue; 70 W m−2; light period 04:00–22:00) on the productivity and physiological traits of tomato plants (Flavance F1) grown in an industrial greenhouse with high pressure sodium (HPS) lamps (235 W m−2, 420 µmol m−2 s−1 at canopy). Physiological trait measurements included diurnal photosynthesis and fruit relative growth rates, fruit weight at specific positions in the truss, root pressure, xylem sap hormone and ion compositions, and fruit quality. In the control treatment with HPS lamps alone, the ratio of far-red to red light (FR:R) was 1.2 at the top of the canopy and increased to 5.4 at the bottom. The supplemental LED inter-lighting decreased the FR:R ratio at the middle and low positions in the canopy and was associated with greener leaves and higher photosynthetic light use efficiency (PLUE) in the leaves in the lower canopy. The use of LED inter-lighting increased the biomass and yield by increasing the fruit weight and enhancing plant growth. The PLUE of plants receiving supplemental LED light decreased at the end of the light period, indicating that photosynthesis of the supplemented plants at the end of the day might be limited by sink capacity. The supplemental LED lighting increased the size of fruits in the middle and distal positions of the truss, resulting in a more even size for each fruit in the truss. Diurnal analysis of fruit growth showed that fruits grew more quickly during the night on the plants receiving LED light than on unsupplemented control plants. This faster fruit growth during the night was related to an increased root pressure. The LED treatment also increased the xylem levels of the phytohormone jasmonate. Supplemental LED inter-lighting increased tomato fruit weight without affecting the total soluble solid contents in fruits by increasing the total assimilates available for fruit growth and by enhancing root activity through an increase in root pressure and water supply to support fruit growth during the night.

Glia alterations in the anterior cingulate cortex (ACC) and dorsolateral prefrontal cortex (DLPFC) have been postulated to play an important role in the pathophysiology of psychiatric disorders. Astroglia is the most abundant type of glial cells in the central nervous system. The expression levels of astrocyte markers (glial fibrillary acidic protein (GFAP), synemin-α, synemin-β, vimentin, nestin) in isolated gray matter from postmortem ACC and DLPFC were determined to investigate the possible involvement of astrocytes in depression. Donors were aged non-suicidal subjects with bipolar disorder (BPD) or major depressive disorder (MDD), and matched controls. GFAP mRNA levels were significantly increased in the ACC of BPD patients. However, GFAP immunohistochemistry showed that the area fraction of GFAP immunoreactive astrocytes was decreased in the ACC of BPD patients, while there were no changes in the cell density and integrated optical density (IOD), indicating that there might be a reduction of GFAP-positive astrocyte processes and remodeling of the astrocyte network in BPD. Furthermore, in controls, DLPFC GFAP mRNA levels were significantly lower with a time of death at daytime (08:01–20:00 h) compared to nighttime (20:01–08:00 h). In depression, such a diurnal pattern was not present. These findings in BPD and MDD subjects warrant further studies given the crucial roles of astrocytes in the central nervous system.

The photoperiod is known to modulate immune cell number and function and is regarded essential for seasonal disease susceptibility. In addition, diurnal variations in the immune system are regarded important for immune competence. Whereas few studies investigated the influence of season, none investigated the specific effect of the photoperiod on these diurnal immune rhythms until now. Therefore, the present study compared diurnal rhythms in cell numbers of peripheral leukocyte types in domestic pigs held either under long day conditions (LD) or short day conditions (SD). Cosinor analyses of cell numbers of various peripheral leukocyte subtypes investigated over periods of 50 h revealed distinct photoperiodic differences in diurnal immune rhythms. Relative amplitudes of cell numbers of total leukocytes, NK cells, T cells, and monocytes in blood were higher under SD than LD. In addition, cell counts of total leukocytes, NK cells, T cells including various T cell subtypes, and eosinophils peaked earlier relative to the time of lights-on under SD than LD. In contrast, diurnal rhythms of neutrophil counts did not show photoperiodic differences. Mesor values did not differ in any leukocyte type. Generalized linear mixed model analyses revealed associations of leukocyte counts with plasma cortisol concentration and activity behavior in most investigated cell types. Moreover, the present study demonstrated photoperiodic effects on diurnal rhythms in plasma cortisol concentrations and activity behavior, which is in agreement with human and primate studies. The results of the present study imply stronger rhythmicity in leukocyte counts in general under SD. Common intrinsic mechanisms seem to regulate photoperiodic effects on diurnal rhythms in leukocyte counts, except for neutrophils, in domestic pigs. Our results reveal considerable insights into the regulation of immune rhythms in diurnally active species.

(1) Background: Retinal pigment epithelial cells (RPE) cells constitutively secrete vascular endothelial growth factor (VEGF) in the retina, protecting the neuronal cells and the choroid. Increased VEGF secretion, however, can result in neovascularization and edema. Many factors regulate VEGF secretion. In this study, we investigated the effect of external stimuli in relation to diurnal rhythm on constitutive VEGF secretion. (2) Methods: Single-eye RPE cell culture was prepared from porcine eyes. RPE cells were cultured in darkness, treated with daylight or room light, and treated with melatonin at different time frames, either respectively or in combination. Supernatants were collected and VEGF content evaluated using ELISA. Expression of the clock protein BMAL1 was evaluated with Western blot. (3) Results: VEGF secretion of the RPE shows a diurnal rhythm. While the rhythm is not influenced by either light or melatonin, the amount of secreted VEGF can be increased by nocturnal melatonin, especially in combination with morning daylight. These findings disclose another layer of VEGF regulation in the retina.

It is a well-known fact that following a proper routine light/dark or diurnal rhythm controls almost all biological processes. With the introduction of modern lighting and artificial illumination systems, continuous exposure to light at night may lead to the disruption of diurnal rhythm. However, the effect of light during the night on brain anatomy, physiology, and human body functions is less explored and poorly understood. In this study, we have evaluated the effect of exposure to dim light (5 lux) at night (dLAN) on Swiss Albino mice over a duration of three consecutive weeks. Results have revealed that exposure to dLAN led to an impairment of cognitive and non-cognitive behaviour, oxidative stress–mediated elevation of lipid peroxidation, and reduction of superoxide dismutase and catalase activity. It also led to the downregulation of hippocampal proteins (BDNF, Synapsin II and DCX) at both protein and mRNA level. Additionally, there was downregulation of CREB and SIRT1 mRNAs and neurodegeneration-associated miRNA21a-5p and miRNA34a-5p. The pyramidal and cortical neurons started showing pyknotic and chromatolysis characteristics. However, a dose of curcumin administered to the mice positively modulated these parameters in our experimental animals. We proposed the modulatory role of curcumin in addressing the deleterious effects of dLAN.

Reduction in atmospheric sulfur and intensified agriculture have led to sulfur deficiency, often correlated with a higher susceptibility to pathogens. The spread of fungal pathogens, such as the soil-born Verticillium longisporum, was observed. Defense responses of infected plants are linked to sulfur-containing compounds including glucosinolates (GSLs). Some pathogens infect their hosts at specific time periods during the day. To investigate the relation of sulfur-containing metabolites with diurnal effects of infection time points, Brassica napus plants cultivated at two different sulfur supplies, were infected with V. longisporum at four different time points during the day. It was demonstrated that 3, 7 and 14 days after inoculation the infected plants differed in their infection rate depending on the time point of infection. Additionally, infected plants had higher contents of sulfur-containing metabolites, such as specific GSLs, in comparison to non-infected plants. Sufficient sulfur fertilization was always reflected in higher contents of sulfur-containing compounds as well as a lower rate of infection compared to sulfur-deprived plants. On the microscopic level vascular occlusions in the hypocotyl were visible and the amount was dependent on the time point of infection. The results might be used to optimize sulfur fertilization to reduce susceptibility to V. longisporum.

Spinal cord injury (SCI) above mid-thoracic levels leads to autonomic dysfunction affecting both the cardiovascular system and thermoregulation. The renin-angiotensin system (RAS) which is a potent regulator of blood pressure, including its novel beneficial arm with the receptor Mas could be an interesting target in post-SCI hemodynamics. To test the hypothesis that hemodynamics, activity and diurnal patterns of those are more affected in the Mas deficient mice post-SCI we used a mouse model of SCI with complete transection of spinal cord at thoracic level 4 (T4-Tx) and performed telemetric monitoring of blood pressure (BP) and heart rate (HR). Our data revealed that hypothermia deteriorated physiological BP and HR control. Preserving normothermia by keeping mice at 30°C prevented severe hypotension and bradycardia post-SCI. Moreover, it facilitated rapid return of diurnal regulation of BP, HR and activity in wild type (WT) mice. In contrast, although Mas deficient mice had comparable reacquisition of diurnal HR rhythm, they showed delayed recovery of diurnal rhythmicity in BP and significantly lower nocturnal activity. Exposing mice with T4-Tx (kept in temperature-controlled cages) to 23°C room temperature for one hour at different time-points post-SCI, demonstrated their inability to maintain core body temperature, Mas deficient mice being significantly more impaired than WT littermates. We conclude that Mas deficient mice were more resistant to acute hypotension, delayed nocturnal recovery, lower activity and more severely impaired thermoregulation. The ambient temperature had significant effect on hemodynamics and, thus it should be taken into account when assessing cardiovascular parameters post-SCI in mice.

Retinal homeostasis is under both diurnal and circadian regulation. We sought to investigate the diurnal expression of autophagy proteins in normal rodent retina and to determine if this is impaired in diabetic retinopathy. C57BL/6J mice and Bio-Breeding Zucker (BBZ) rats were maintained under a 12h/12h light/dark cycle and eyes, enucleated over a 24 h period. Eyes were also collected from diabetic mice with two or nine-months duration of type 1 diabetes (T1D) and Bio-Breeding Zucker diabetic rat (BBZDR/wor rats with 4-months duration of type 2 diabetes (T2D). Immunohistochemistry was performed for the autophagy proteins Atg7, Atg9, LC3 and Beclin1. These autophagy proteins (Atgs) were abundantly expressed in neural retina and endothelial cells in both mice and rats. A differential staining pattern was observed across the retinas which demonstrated a distinctive diurnal rhythmicity. All Atgs showed localization to retinal blood vessels with Atg7 being the most highly expressed. Analysis of the immunostaining demonstrated distinctive diurnal rhythmicity, of which Atg9 and LC3 shared a biphasic expression cycle with the highest level at 8:15 am and 8:15 pm. In contrast, Beclin1 revealed a 24-h cycle with the highest level observed at midnight. Atg7 was also on a 24-h cycle with peak expression at 8:15am, coinciding with the first peak expression of Atg9 and LC3. In diabetic animals, there was a dramatic reduction in all four Atgs and the distinctive diurnal rhythmicity of these autophagy proteins was significantly impaired and phase shifted in both T1D and T2D animals. Restoration of diurnal rhythmicity and facilitation of autophagy protein expression may provide new treatment strategies for diabetic retinopathy.

The effects of abiotic factors (rate of PAR, air temperature and relative humidity, vapor pressure deficit) on the daily dynamics of the water potential in foliated (needled) shoots of Scots pine (Pinus sylvestris L.) and silver birch (Betula pendula Roth) trees during the growing season were studied in a fresh bilberry pine forest in the European part of the middle taiga (southern Karelia). Based on the analysis of model data, it was established that the contributions of the leading environmental factors to the formation of the water potential in coniferous and deciduous plants are comparable, and no interspecific differences were found. The similarity of the environmental factors dominance is shown for the two species, namely PAR rate effect dominance in July, relative air humidity in August, air temperature in September. In June, however, significant differences between the species were revealed in the governing influence of environmental factors on the water exchange in Scots pine (relative air humidity) and silver birch (PAR rate). These differences are supposed to be due to the biological traits of the formation of shoots and leaves (needles) in the coniferous and deciduous plants during the period of intensive growth. At the same time, we observed a somewhat inert response of the water potential in the foliated shoots of woody plants to abrupt changes in abiotic factors during the day, which is due to the mechanism of endogenous regulation of the water exchange. The similarity of the leading abiotic factors and their contributions to the formation of the water potential for coniferous and deciduous woody plants through the growing season suggests that taxonomically different species growing in the same climatic region have similar adaptation mechanisms.

Measuring salivary cortisol is both convenient and non-invasive for patients; however, its usefulness as a marker for monitoring medical therapy has not yet been established. The aim of this study was to assess the utility of multiple salivary cortisol measurements in patients with Cushing’s syndrome (CS) during medical therapy. Six patients with CS (three with cortisol-secreting adrenocortical adenoma and three with ACTH-secreting pituitary adenoma) were recruited. Samples for morning serum cortisol, urinary free cortisol (UFC), and multiple salivary cortisol levels were collected before and during metyrapone treatment. The area under the curve (AUC) and mean value (MV) of daily salivary cortisol levels were calculated. In five out of six patients, UFC were normalized; however, multiple salivary cortisol measurements revealed an impaired diurnal cortisol rhythm in these patients. To verify the usefulness of multiple salivary cortisol measurements, we performed a prospective case study of a patient in whom the excess secretion of cortisol was not controlled (UFC 211 μg/day) with 2,250 mg/day in four divided doses of metyrapone. Multiple measurements of salivary cortisol revealed that cortisol levels elevated before the next administration. Accordingly, we shortened the interval by increasing the number of administration from four to five times per day, with a slight increment of daily dose of 2,500 mg. These optimizations resulted in a drastic improvement of diurnal pattern as well as UFC level (101 μg/day). Changes in both the MV and AUC of salivary cortisol levels were more correlated with those in UFC levels (Correlation coefficient 0.75, p = 0.007, and 0.70, p = 0.017) than those in the morning serum cortisol levels (0.42, p = 0.200), indicating that multiple salivary cortisol measurements reflect more precisely the excess secretion of cortisol. Our preliminary data suggest that multiple salivary cortisol measurements can be a useful tool to visualize the diurnal cortisol rhythm and to determine the dose and timing of metyrapone during the treatment in patients with CS.

Abstract To test the hypothesis that use of oral contraceptives (OC) changes diurnal variation in fluid balance mechanisms including blood pressure, secretion of vasopressin and oxytocin, and renal water and electrolyte excretion. Fifteen naturally cycling (NC) women in mid‐follicular phase and 11 long‐term OC users were included in a 24‐h standardized inpatient study for measurements of vasopressin, oxytocin, sodium, and osmolality in plasma as well as urinary excretion of electrolytes, aquaporin‐2, and prostaglandin E2. Blood pressure and heart rate were monitored noninvasively. Plasma vasopressin showed circadian rhythm (P = 0.02) and were similar in both groups (P = 0.18) including nighttime increases (P

Health of tropical coral reefs depends largely on the balance between constructive (calcification and cementation) and destructive forces (mechanical-chemical degradation). Gradual increase in dissolved CO2 and the resulting decrease in carbonate ion concentration (“ocean acidification”) in ocean surface water may tip the balance toward net mass loss for many reefs. Enhanced nutrients and organic loading in surface waters (“eutrophication”), may increase the susceptibility of coral reef and near shore environments to ocean acidification. The impacts of these processes on coral calcification have been repeatedly reported, however the synergetic effects on bioerosion rates by sponges are poorly studied. Erosion by excavating sponges is achieved by a combination of chemical dissolution and mechanical chip removal. In this study, Cliona caribbaea, a photosymbiont-bearing excavating sponge widely distributed in Caribbean reef habitats, was exposed to a range of CO2 concentrations, as well as different eutrophication levels. Total bioerosion rates, estimated from changes in buoyant weights over 1 week, increased significantly with pCO2 but not with eutrophication. Observed chemical bioerosion rates were positively affected by both pCO2 and eutrophication but no interaction was revealed. Net photosynthetic activity was enhanced with rising pCO2 but not with increasing eutrophication levels. These results indicate that an increase in organic matter and nutrient renders sponge bioerosion less dependent on autotrophic products. At low and ambient pCO2, day-time chemical rates were ~50% higher than those observed at night-time. A switch was observed in bioerosion under higher pCO2 levels, with night-time chemical bioerosion rates becoming comparable or even higher than day-time rates. We suggest that the difference in rates between day and night at low and ambient pCO2 indicates that the benefit of acquired energy from photosynthetic activity surpasses the positive effect of increased pCO2 levels at night due to holobiont respiration. This implies that excavation must cost cellular energy, by processes, such as ATP usage for active Ca2+ and/or active proton pumping. Additionally, competition for dissolved inorganic carbon species may occur between bioerosion and photosynthetic activity by the symbionts. Either way, the observed changing role of symbionts in bioerosion can be attributed to enhanced photosynthetic activity at high pCO2 levels.

Diurnal dynamics of necessity of socialized emotional experiences (SEE) was researched with the help of the B.I. Dodonov diagnostic checklist. The data for 514 women and 252 men were collecting from 1994 to 2013 years. The mean age of responders was 29,4 years. Significant and reliable changes in SEE markers were found in relation to diurnal variations and it was different for men and women. Analysis of findings for the periods of 1994-2006 and 2009-2013 confirmed the diurnal variations of SEE. Furthermore, SEE markers and their dynamics can undergo significant changes due to long-term variations. The adaptive function of motivation displays in it as a result of variability natural and social environment.

The daily change of light and dark periods influences different physiological processes including feeding, resting and locomotor activity. Previously, several studies on mammalian models revealed a strong link between day-night rhythms and key immunological parameters. Since teleost fishes possess innate and adaptive immune responses like those observed in higher vertebrates, we aimed to elucidate how changes in light-dark cycles shape the immune system of fish. Using the rainbow trout laboratory model, we investigated the link between diurnal rhythms and immune competence of fish. Initially, the cell composition and phagocytic activity of leukocytes was analyzed in the circulation as well as in the head kidney, the functional ortholog of mammalian bone marrow. Once the baseline was established, we evaluated the ability of fish to respond to a bacterial stimulus, as well as the changes in antimicrobial activity of the serum. Our results suggest increased immune competence during the day, manifested by the higher presence of myeloid cells in the circulation; increased overall phagocytic activity; and higher capacity of the sera to inhibit the growth of Aeromonas salmonicida. Notably, our flow cytometric analysis identified the myeloid cells as the major population influenced by the time of day, whereas IgM+ B cells and thrombocytes did not vary in a significant manner. Interestingly, the presence of myeloid cells in blood and head kidney followed complementary trends. Thus, while we observed the highest number of myeloid cells in the blood during early morning, we witnessed a reverse trend in the head kidney, suggesting a homing of myeloid cells to reservoir niches with the onset of the dark phase. Further, the presence of myeloid cells was mirrored in the expression of the proinflammatory marker tnfa as well as in the number of leukocytes recruited to the peritoneal cavity in the peritonitis model of inflammation. Overall, the data suggest a connection between diurnal rhythms and the immune response of rainbow trout and highlight the relevance of rhythmicity and its influence on experimental work in the field of fish chronoimmunology.

Melatonin 2-hydroxylase (M2H) catalyzes the conversion of melatonin into 2hydroxymelatonin (2OHM), which is present in plants at a higher concentration than melatonin. Although M2H has been cloned, the in vivo function of its product is unknown. Here, we generated stable T2 homozygous transgenic rice plants in which expression of endogenous M2H was suppressed (RNAi lines). However, we failed to generate M2H overexpression transgenic rice due to failure of somatic embryogenesis. The M2H transcript level showed a diurnal rhythm with a peak at night concomitantly with the peak concentration of 2OHM. RNAi rice showed a reduced M2H mRNA level and 2OHM and melatonin concentrations. The unexpected decrease in the melatonin concentration was caused by redirection of melatonin into cyclic 3hydroxymelatonin via a detour catabolic pathway. Thus, the decrease in the melatonin concentration in M2H RNAi rice led to slowed seedling growth and delayed germination. By contrast, the transient increase in the melatonin concentration was of greater magnitude in the M2H RNAi than the wild-type rice upon cadmium treatment due to possible suppression of melatonin degradation. Due to its higher concentration of melatonin, the M2H RNAi rice displayed tolerance to senescence, salt, and tunicamycin stresses. Therefore, the increase in the melatonin concentration caused by suppression of melatonin degradation or by overexpression of melatonin biosynthetic genes enhances stress tolerance in rice.

Actin is the most abundant protein in eukaryotic cells and is a key cytoskeletal component controlling cell morphology and motility. In this study, four MiACT genes were isolated from mango by homological cloning and designated as MiACT1, MiACT4, MiACT7, and MiACT9. Sequence alignments and phylogenetic analysis demonstrated that the four MiACT genes of mango were highly similar to each other at the nucleotide and amino acid levels. All of four MiACT proteins showed high similarity to the known actin proteins from other species. Reverse transcription polymerase chain reaction revealed that the four MiACT genes were constitutively and stably expressed in all organs tested. Application of plant growth regulators and four stress treatments had a remarkable effect on the expression of MiACT4, MiACT7 and MiACT9, whereas expression of MiACT1 was unresponsive. In contrast, the expression profiles of the four MiACT genes were not regulated by diurnal rhythms. Moreover, the expression of MiACT1 was not affected by heavy metal treatments and the transcript level of MiACT1 was rather stable in different days during the post-harvest period either under treatment or not. Our results suggest that the four actin genes play important roles throughout the entire life cycle of mango; the constitutively and stably expressed MiACT1 is the best candidate as an internal standard for differential gene expression analysis in mango.

Background: More attention is being paid lately to polycystic ovary syndrome (PCOS) not only in the aspect of fertility but also according to long-term metabolic and cardiovascular abnormalities. Observations of women with PCOS show that the occurrence of blood hypertension is more frequent after the menopause. There are few articles concerning the predictable symptoms of blood hypertension. It seems that twenty-four hour blood pressure monitoring and assessment of changes of diurnal rhythm could be useful in this group of patients.Aim of the study: The purpose of this study was to assess diurnal changes of blood pressure in women with polycystic ovary syndrome.Material and methods: 26 women with PCOS diagnosed according to Rotterdam consensus criteria and Androgen Excess Society (AES) criteria were included in our study. The mean age of the examined women was 29.5 years and the mean BMI (body mass index) was 24.7 kg/m2. The control group consisted of 12 age-matched women, without PCOS. Twenty-four hour Holter monitoring of ambulatory blood pressure was performed during normal daily activity in all patients. Halberg’s cosinor method was used to analyse daily biorhythm.Results: Results show the diurnal changes of systolic blood pressure in the preclinical phase in 30% and diastolic in 15% of PCOS women. In this group no physiological decrease of blood pressure at night time was observed.

The aim of this work was to investigate the behaviour patterns of a cage-housed breeding flock of pheasants during the day in the early stage of laying period, and evaluate the differences in behaviour patterns between male and female pheasants. Observations were carried out with a flock of common pheasants (Phasianus colchicus) consisting of 1 male and 5 female pheasants aged 2 years that showed a minimum rate of aggression in the previous laying. Behaviour patterns of birds were studied using a 15-minute video recording taken at each hour during the day (from 7 a.m. until 7 p.m.). The rates of activities such as feeding, movement, resting, scratching, preening, mating and aggression in female pheasants differed significantly from those in the male, as observed throughout the day. The rate of feeding had 2 peaks in hens (in early morning and late evening). Generally, the feed intake in females was observed throughout the day whereas the male received feed less frequently but at a higher rate, particularly in the afternoon. The highest rate of movement was observed for both male and female pheasants in morning hours followed by a decline in movement activities which was slow in hens and rapid in the cock, with the subsequent second peak before dark. Except for 7 a.m., resting was among behaviour patterns with the highest rate in both genders throughout day, with lower rates in females as compared to the male. The stereotype behaviour was observed in hens more frequently, with a peak in a period from 9 a.m. to 12 a.m. The highest frequency of mating was observed in the evening after 7 p.m.

Under adequate sulfur supply, plants accumulate sulfate in the vacuoles and use sulfur-containing metabolites as storage compounds. Under sulfur-limiting conditions, these pools of stored sulfur-compounds are depleted in order to balance the nitrogen to sulfur ratio for protein synthesis. Stress conditions like sulfur limitation and/or pathogen attack induce changes in the sulfate pool and the levels of sulfur-containing metabolites, which often depend on the ecotypes or cultivars. We are interested in investigating the influence of the genetic background of canola (Brassica napus) cultivars in sulfur-limiting conditions on the resistance against Verticillium longisporum. Therefore, four commercially available B. napus cultivars were analyzed. These high-performing cultivars differ in some characteristics described in their cultivar pass, such as several agronomic traits, differences in the size of the root system, and resistance to certain pathogens, such as Phoma and Verticillium. The objectives of the study were to examine and explore the patterns of morphological, physiological and metabolic diversity in these B. napus cultivars at different sulfur concentrations and in the context of plant defense. Results indicate that the root systems are influenced differently by sulfur deficiency in the cultivars. Total root dry mass and length of root hairs differ not only among the cultivars but also vary in their reaction to sulfur limitation and pathogen attack. As a sensitive indicator of stress, several parameters of photosynthetic activity determined by PAM imaging showed a broad variability among the treatments. These results were supported by thermographic analysis. Levels of sulfur-containing metabolites also showed large variations. The data were interrelated to predict the specific behavior during sulfur limitation and/or pathogen attack. Advice for farming are discussed.

Six populations of the freshwater red alga Batrachospermum delicatulum (Skuja) Necchi & Entwisle, including gametophyte and 'Chantransia' stage, were analysed in culture and natural conditions applying chlorophyll fluorescence and oxygen evolution. Parameters derived from the photosynthesis-irradiance curves indicated adaptation to low irradiance for all populations, which was characterized by photoinhibition, low values of Ik and Ic and high values of a. Data from both techniques revealed significant differences among populations and phases for most photosynthetic parameters. Similarly, photosynthesis responded differently to variations in temperature in each population with similar rates under a wide range of temperature. No consistent pattern was found when the same population or phase was tested, suggesting high capacity to adjust the photosynthetic apparatus to distinct conditions of irradiance and temperature. pH experiments showed a decreasing trend towards higher pH or higher rates at pH 6.5, suggesting, respectively, higher affinity to inorganic carbon as CO2 or indistinct use of bicarbonate and CO2. The diurnal pattern of photosynthesis essentially agree with that for seaweeds and freshwater red algae, consisting of two peaks: a first (generally higher) during the morning and a second (typically lower) in the afternoon. Photosynthetic characteristics of B. delicatulum (Skuja) Necchi & Entwisleexhibited a wide range of responses to irradiance, temperature and pH/inorganic carbon, reflecting its wide tolerance to these variables, which probably contributes to its wide spatial and temporal distribution.Seis populações da alga vermelha Batrachospermum delicatulum (Skuja) Necchi & Entwisle, incluindo gametófito e estágio 'Chantransia', foram analisadas em condições de campo e cultura aplicando as técnicas de fluorescência da clorofila e oxigênio dissolvido. Parâmetros derivados das curvas fotossíntese-irradiância indicaram adaptação a baixa irradiância em todas populações, que foi caracterizada por fotoinibição, baixos valores de Ik e Ic e altos valores de a. Dados de ambas técnicas revelaram diferenças significativas entre populações e fases para a maioria dos parâmetros. A fotossíntese também respondeu diferentemente a variações de temperatura em cada população, com taxas semelhantes sob ampla faixa de temperatura. Nenhum padrão consistente foi encontrado quando a mesma população ou fase foi testada, sugerindo alta capacidade para ajustar o aparato fotossintético a distintas condições de temperatura e irradiância. Experimentos de pH mostraram tendência decrescente sob pH mais alto ou taxas maiores em pH 6,5 sugerindo, respectivamente, maior afinidade por carbono inorgânico como CO2 ou uso indistinto de bicarbonato e CO2. O padrão de variação diurna observado concorda com o de macroalgas marinhas e algumas rodófitas continentais, consistindo de dois picos: o primeiro (geralmente maior) durante a manhã e o segundo (tipicamente menor) à tarde. As características fotossintéticas de B. delicatulum (Skuja) Necchi & Entwislemostraram amplas respostas à irradiância, temperatura e pH/carbono inorgânico, refletindo sua ampla tolerância à estas variáveis, que provavelmente contribui para sua ampla distribuição espacial e temporal.

The circadian rhythm of behavior has interested many researchers in the past decades, yet amazingly little is known on the evolution of natural variation in circadian rhythms of behavior. Most research has been focused on identifying the circadian clock genes that form an intricate clock network, which turns out to be more complex with every discovery. To understand the importance of circadian rhythms of behavior in speciation, genetic analyses should be conducted on intra- and interspecific allochronic differentiation of behaviors. Many moth species show specific daily activity rhythms in their sexual activities, some species being sexually active early at night, while others are sexually active late at night. This differentiation has been suggested to have arisen to minimize communication interference between closely related species, as co-occurring and closely related species with overlapping sex pheromone blends show a temporal differentiation in their daily sexual activities. However, the genetic differentiation of this allochronic separation has barely been examined in any species so far. In this review I summarize studies conducted on timing of sexual activities in moths, and which factors have been found to influence this timing, with the aim to identify the gaps and challenges, to unravel the possible contribution of allochronic differentiation of sexual activities in moth speciation.