Cardiac Myxoid Spindle Cell Tumor in a Neonate.

Introduction: Different subtypes of cardiac tumors containing spindle cells have been described as cardiac sarcoma. However, benign types have not been reported so far. We described a neonate with progressive respiratory distress who had a PDA and was finally diagnosed with a right atrial spindle cell tumor. Case Presentation: The patient was a neonate referred with respiratory distress and sepsis. The initial echocardiography demonstrated a small atrial septal defect, patent ductus arteriosus, and a heterogeneous rounded right atrial mass lesion. Pathologic examination confirmed the right atrial myxoid spindle cell tumor without local invasion. Successful mass resection was performed, and follow-up echocardiography revealed normal cardiac structure and function. Conclusion: In infants with manifestations of possible cardiac anomalies, it is necessary to consider other pathologies, such as neoplastic processes. Spindle cell detection in pathology is not ominous all the time, and there are benign subtypes with favorable outcomes after successful surgical resection.

The Prevalence of Depression and Anxiety and Its Association with Sleep Quality in the First-Year Medical Science Students.

Methods: A total number of 471 freshmen students (NUMS) participated in the study, pinpointing that the data are collected in 2019 and 2020. In line with measuring depression, anxiety, and sleep quality, the Persian Beck Depression Inventory-II, Beck Anxiety Inventory, and Pittsburgh Sleep Quality Index were employed. The associations between depression and anxiety with sleep quality were assessed by using the multiple logistic regression model. All statistical analyses were conducted in STATA14, and the significant level was set at P < 0.05. Results: The prevalence of depression, anxiety, and poor sleep quality in the study population was 21.4%, 31.9%, and 28%, respectively. Analytical analyses indicated that after adjusting for studied covariates, the odds of poor sleep quality in individuals with depression were 3.5 times higher compared to the counter group (P < 0.001). Moreover, the odds of poor sleep quality in individuals with anxiety were 2.1 times higher compared to the counter group (P < 0.001). Conclusion: Noticeable proportion of freshmen students suffer from depression and anxiety; in line with such a critical issue, our study found that depression and anxiety had a statistical association with sleep quality in study population. From this respect, it seems that providing essential interventions and psychological counseling services could be constructive for the freshmen medical students.

Anti-inflammatory and antioxidative effects of thiamin supplements in patients with gestational diabetes mellitus.

OBJECTIVE: The aim of this study was to evaluate the effects of thiamin supplementation on biomarkers of inflammation and oxidative stress in patients with gestational diabetes mellitus (GDM). METHODS: This randomized, double-blind, placebo-controlled trial was conducted among 60 patients with GDM. Patients were randomly allocated into two groups to receive either 100 mg/day thiamin supplements (n = 30) or placebo (n = 30) for 6 weeks. RESULTS: Thiamin supplementation significantly decreased serum high-sensitivity C-reactive protein (hs-CRP) (ß - 0.98 mg/L; 95% CI, -1.54, -0.42; p = .001) and plasma malondialdehyde (MDA) levels (ß - 0.86 µmol/L; 95% CI, -1.15, -0.57; p < .001) when compared with the placebo. In addition, thiamin supplementation downregulated gene expression of tumor necrosis factor-alpha (TNF-α) (p = .002) in peripheral blood mononuclear cells of patients with GDM. Thiamin supplementation did not affect other biomarkers of inflammation and oxidative stress. CONCLUSION: Overall, thiamin supplementation for 6 weeks to patients with GDM significantly reduced hs-CRP and MDA levels, and gene expression of TNF-α, but did not affect other biomarkers of inflammation and oxidative stress. CLINICAL TRIAL REGISTRATION NUMBER: Clinical Trials.govIdentifier no. http://www.irct.ir: IRCT20170513033941N58.

High Stocking Density and Food Deprivation Increase Brain Monoaminergic Activity in Gilthead Sea Bream (Sparus aurata).

In teleosts, brain monoamines (dopamine and serotonin) participate in the early response to different acute stressors. However, little is known regarding their role during chronic stress. In a 2 × 2 factorial design, the influence of a high stocking density (HSD) and/or food deprivation (FD) on the brain monoaminergic activity in gilthead sea bream (Sparus aurata) was evaluated. Following a 21-day experimental design, samples from the plasma and brain regions (telencephalon, hypothalamus, and optic tectum) were collected. The dopamine (DA), serotonin (5HT), and their main metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC) and 5 hydroxyindoleacetic acid (5HIAA), contents were HPLC-assessed in brain tissues, and the ratios DOPAC/DA and 5HIAA/5HT were calculated as indicators of enhanced monoaminergic activity. The plasma levels of cortisol and catecholamine were also evaluated. The cortisol levels increased in fish exposed to HSD and normally fed but, also, in all FD groups, whereas the NA levels decreased in LSD-FD animals. Within the brain, the dopaminergic and serotonergic activities in telencephalon and hypothalamus increased in fish subjected to HSD and in the telencephalon of LSD-FD fish. While DA (hypothalamus) and 5HT (telencephalon) increased in the animals submitted to a HSD, food-deprived fish did not show such an increase. Taken together, our results supported the hypothesis of brain monoaminergic activity participating in maintaining and orchestrating the endocrine response to chronic stress in fish.

Central serotonin participates in the anorexigenic effect of GLP-1 in rainbow trout (Oncorhynchus mykiss).

The incretin, glucagon-like peptide-1 (GLP-1) is a major player in the gut-brain axis regulation of energy balance and in fish it seems to exert a negative influence on food intake. In this study, we investigated the role of the brain serotonergic system in the effects promoted by a peripheral GLP-1 injection on food intake in rainbow trout (Oncorhynchus mykiss). For this, in a first experiment the incretin was intraperitoneally injected (100 ng/g body weight) alone or in combination with a 5HT2C receptor antagonist (SB 242084, 1 µg/g body weight) and food intake was measured 30, 90, and 180 min later. In a second experiment, we studied the effect of these treatments on mRNA abundance of hypothalamic neuropeptides that control food intake. In addition, the effect of GLP-1 on serotonin metabolism was assessed in hindbrain and hypothalamus. Our results show that GLP-1 induced a significant food intake inhibition, which agreed with the increased expression of anorexigenic neuropeptides pomc and cart in the hypothalamus. Furthermore, GLP-1 stimulated the synthesis of serotonin in the hypothalamus, which might be indicative of a higher use of the neurotransmitter. The effects of GLP-1 on food intake were partially reversed when a serotonin receptor antagonist, SB 242084, was previously administered to trout. This antagonist also reversed the stimulatory effect of the hormone in hypothalamic pomca1 mRNA abundance. We conclude that hypothalamic serotonergic pathways are essential for mediating the effects of GLP-1 on food intake in rainbow trout. In addition, the 5HT2C receptor subtype seems to have a prominent role in the inhibition of food intake induced by GLP-1 in this species.

The effects of zinc supplementation on clinical response and metabolic profiles in pregnant women at risk for intrauterine growth restriction: a randomized, double-blind, placebo-controlled trial.

OBJECTIVE: This investigation was conducted to assess the effects of zinc supplementation on clinical response and metabolic status among pregnant women at risk for intrauterine growth restriction (IUGR). METHODS: This randomized, double-blind, placebo-controlled, clinical trial was conducted among 52 women at risk for IUGR according to abnormal uterine artery Doppler waveform. Participants were randomly assigned to take either 233 mg zinc gluconate (containing 30 mg zinc) supplements (n = 26) or placebo (n = 26) for 10 weeks from 17 to 27 weeks of gestation. Fasting blood samples were taken at baseline and after the 10-week treatment to quantify related variables. RESULTS: After the 10-week intervention, taking zinc led to a significant reduction in serum high-sensitivity C-reactive protein (hs-CRP) (ß â€’1.17 mg/L; 95% CI, -1.77, -0.57; p < .001) and plasma malondialdehyde (MDA) levels (ß -0.23 µmol/L; 95% CI, -0.45, -0.02; p = .03); also a significant rise in total antioxidant capacity (TAC) (ß 59.22 mmol/L; 95% CI, 25.07, 93.36; p = .001) was observed in comparison to placebo. In addition, zinc supplementation significantly reduced serum insulin (ß -1.33 µIU/mL; 95% CI, -2.00, -0.67; p < .001) and insulin resistance (ß -0.30; 95% CI, -0.44, -0.15; p < .001), and significantly increased insulin sensitivity (ß 0.008; 95% CI, 0.003, 0.01; p < .001) compared with the placebo. Zinc supplementation did not influence pulsatility index (PI) and other metabolic parameters. CONCLUSIONS: Overall, zinc supplementation in pregnant women at risk for IUGR had beneficial effects on TAC, MDA, hs-CRP, and insulin metabolism, but did not affect PI and other metabolic profiles.

The effects of n-3 fatty acids from flaxseed oil on genetic and metabolic profiles in patients with gestational diabetes mellitus: a randomised, double-blind, placebo-controlled trial.

The present study was performed to evaluate the effects of n-3 fatty acids from flaxseed oil on genetic and metabolic profiles in patients with gestational diabetes mellitus (GDM). This randomised, double-blind, placebo-controlled clinical trial was performed in sixty women with GDM. Participants were randomly divided into two groups to intake either 2 × 1000 mg/d n-3 fatty acids from flaxseed oil containing 400 mg α-linolenic acid in each capsule (n 30) or placebo (n 30) for 6 weeks. n-3 Fatty acid intake up-regulated PPAR-γ (P < 0·001) and LDL receptor (P = 0·004) and down-regulated gene expression of IL-1 (P = 0·002) and TNF-α (P = 0·001) in peripheral blood mononuclear cells of subjects with GDM. In addition, n-3 fatty acid supplementation reduced fasting plasma glucose (P = 0·001), insulin levels (P = 0·001) and insulin resistance (P < 0·001) and increased insulin sensitivity (P = 0·005) when compared with the placebo. Additionally, n-3 fatty acid supplementation was associated with a decrease in TAG (P < 0·001), VLDL-cholesterol (P < 0·001), total cholesterol (P = 0·01) and total cholesterol:HDL-cholesterol ratio (P = 0·01) when compared with placebo. n-3 Fatty acid administration was also associated with a significant reduction in high-sensitivity C-reactive protein (P = 0·006) and malondialdehyde (P < 0·001), and an increase in total nitrite (P < 0·001) and total glutathione levels (P = 0·006) when compared with the placebo. n-3 Fatty acid supplementation for 6 weeks to women with GDM had beneficial effects on gene expression related to insulin, lipid and inflammation, glycaemic control, lipids, inflammatory markers and oxidative stress.

Differential circadian and light-driven rhythmicity of clock gene expression and behaviour in the turbot, Scophthalmus maximus.

In fish, the circadian clock represents a key regulator of many aspects of biology and is controlled by combinations of abiotic and biotic factors. These environmental factors are frequently manipulated in fish farms as part of strategies designed to maximize productivity. The flatfish turbot, Scophthalmus maximus, represents one of the most important species within the aquaculture sector in Asia and Europe. Despite the strategic importance of this species, the function and regulation of the turbot circadian system remains poorly understood. Here, we have characterized the core circadian clock genes, clock1, per1, per2 and cry1 in turbot and have studied their daily expression in various tissues under a range of lighting conditions and feeding regimes. We have also explored the influence of light and feeding time on locomotor activity. Rhythmic expression of the four core clock genes was observed in all tissues studied under light dark (LD) cycle conditions. Rhythmicity of clock gene expression persisted upon transfer to artificial free running, constant conditions confirming their endogenous circadian clock control. Furthermore, turbot showed daily cycles of locomotor activity and food anticipatory activity (FAA) under LD and scheduled-feeding, with the activity phase as well as FAA coinciding with and being dependent upon exposure to light. Thus, while FAA was absent under constant dark (DD) conditions, it was still detected in constant light (LL). In contrast, general locomotor activity was arrhythmic in both constant darkness and constant light, pointing to a major contribution of light, in concert with the circadian clock, in timing locomotor activity in this species. Our data represents an important contribution to our understanding of the circadian timing system in the turbot and thereby the optimization of rearing protocols and the improvement of the well-being of turbot within fish farming environments.

Influence of Stress on Liver Circadian Physiology. A Study in Rainbow Trout, Oncorhynchus mykiss, as Fish Model.

In vertebrates stress negatively affects body homeostasis and triggers a battery of metabolic responses, with liver playing a key role. This organ responds with altered metabolism, leading the animal to cope with the stress situation, which involves carbohydrate and lipid mobilization. However, metabolism among other physiological functions is under circadian control within the liver. Then, metabolic homeostasis at system level involves circadian timing systems within tissues and cells, and collaborate with each other. During chronic stress, cortisol maintains the liver metabolic response by modulating carbohydrate- and lipid-related metabolism. Stress also disrupts the circadian oscillator within the liver in mammals, whereas little information is available in other vertebrates, such as fish. To raise the complexity of this process, other candidates may mediate in such effect of stress. In fact, sirtuin1, a link between cellular sensing of energy status and circadian clocks, participates in the response to stress in mammals, but no information is available in fish. Considering the role played by liver in providing energy for the animal to deal with an adverse situation, and the existence of a circadian oscillator within this tissue, jeopardized liver circadian physiology during stress exposure might be expected. Whether the physiological response to stress is a well conserved process through the phylogeny and the mechanisms involved in such response is a question that remains to be elucidated. Then, we provide information at this respect in mammals and show comparable results in rainbow trout as fish animal model. Similar to that in mammals, stress triggers a series of responses in fish that leads the animal to cope with the adverse situation. Stress influences liver physiology in fish, affecting carbohydrate and lipid metabolism-related parameters, and the circadian oscillator as well. In a similar way than that of mammals different mediators participate in the response of liver circadian physiology to stress in fish. Among them, we confirm for the teleost rainbow trout a role of nuclear receptors (rev-erbß), cortisol, and sirt1. However, further research is needed to evaluate the independent effect of each one, or the existence of any interaction among them.

SIRT1 mediates the effect of stress on hypothalamic clock genes and food intake regulators in rainbow trout, Oncorhynchus mykiss.

Stress negatively affects a wide range of physiological and behavioural functions (circadian physiology and food intake, among others), thus compromising animal welfare. Cortisol mediates the effect of stress on food intake, but other mediators (such as sirtuins) may participate in that related to circadian physiology. We evaluated 1) the effect of stress on the day-night variation of hypothalamic clock genes and food intake regulators, 2) changes of mRNA abundance in cortisol biosynthesis at the head kidney, and 3) changes of glucocorticoid receptors in both tissues of rainbow trout, together with the involvement of SIRT1 in such effect. Trout receiving or not SIRT1 inhibitor (EX527) and subjected or not to stress by high stocking density (72 h), were sampled at day- (ZT10) and night-time (ZT18). Our results indicate that SIRT1 mediates the effect of stress on mRNA abundance of clock genes in trout hypothalamus, but it also influences those changes occurring on food intake-related peptides. High stocking density inhibits clock genes expression, but enhances that of food intake-related peptides. EX527 treatment prevents stress-related changes observed in clock genes, thus evidencing a key role played by SIRT1 in mediating this effect on trout circadian oscillators. On the other hand, EX527 treatment partially prevents changes of food intake-related peptides, indicating that an interaction between SIRT1 and other mediators (such as cortisol) exists during response to stress. In support of that, our results reveal that SIRT1 influences cortisol biosynthesis during stress. Whatever the case is, further research will help understanding the underlying mechanisms involved.

The prevalence, comorbidity and socio-demographic factors of depressive disorder among Iranian children and adolescents: To identify the main predictors of depression.

BACKGROUND: Depressive disorders are a major public health problem in developed and developing countries. Recently, several risk factors have been described for depressive disorders in children and adolescents. The aim of the present study was to identify the main risk factors that can affect the incidence of depression in Iranian children and adolescents. METHODS: A total of 30,546 children and adolescents (between 6 and 18 years of age) participated in a cross-sectional study to identify the predictors of depressive disorders. Depressive disorders were assessed using the Persian version of the Kiddie Schedule for Affective Disorders and Schizophrenia (K-SADS-PL). In addition, a demographic characteristics questionnaire was completed by parents of the participants. The data was analyzed using the SPSS22 software via performing the descriptive analysis and the multiple logistic regression analysis methods. P-values less than 0.05 were considered statistically significant. RESULTS: Results showed that a higher age (15-18), being female, and the father's unemployment were associated with an increased odds ratio for depressive disorders. The age of 10-14 (OR = 2.1; 95% CI, 1.57-2.81), the age of 15-18 (OR = 4.44; 95% CI, 3.38-5.83), female gender (OR = 1.44; 95% CI, 1.2-1.73) and the father's unemployment (OR = 1.59; 95% CI, 1.01-2.5) were significant positive predictors, whereas, the mother's job (as a housewife) (OR = 0.66; 95% CI, 0.45-0.96) and a history of psychiatric hospitalization of the father and mother (OR = 0.34; 95% CI, 0.15-0.78 and OR = 0.34; 95% CI, 0.14-0.84) were negative predictors for depressive symptoms. CONCLUSION: Depressive symptoms are common in children and adolescents and are correlated with age and gender. The assessment of the prevalence of psychiatric disorders, especially the depressive disorders and their comorbidities, may help to prevent mood disorders in children and adolescents.

The Augmenting Effects of the tDNA Insulator on Stable Expression of Monoclonal Antibody in Chinese Hamster Ovary Cells.

Cell line development is one of the most critical steps in the production of complex recombinant therapeutic proteins such as monoclonal antibodies in mammalian cells. Generation of industrial cell lines is mainly based on the time-consuming and laborious process of selection and screening of a large number of clones. With the increasing demand for therapeutic proteins during the past years, more effort is invested to improve the efficiency of cell line development. In line with this premise, several studies employed expression vector engineering strategies based on incorporation of epigenetic regulatory elements, which can enhance the expression level and stability of the transgenes. Main examples of such elements include ubiquitous chromatin opening elements, scaffold or matrix attachment regions, stabilizing antirepressor elements, and insulators. This work evaluates the utility of the tDNA insulator element for stable expression of an IgG1 monoclonal antibody as well as the enhanced green fluorescent protein (EGFP) reporter gene in Chinese hamster ovary (CHO) cells. Initial analysis of EGFP transfected cells showed improved mean fluorescent intensity in cell pools and single cell clones when tDNA element was included in the expression vector. Our results also indicated up to nine- and sixfold enhancements in antibody titer and specific productivity of clones derived from tDNA containing vectors, respectively. Moreover, improved single cell cloning efficiency was observed for transfectants generated using tDNA harboring expression constructs. Our study clearly shows the beneficial effects of the tDNA insulator on monoclonal antibody expression in CHO cells.

Involvement of cortisol and sirtuin1 during the response to stress of hypothalamic circadian system and food intake-related peptides in rainbow trout, Oncorhynchus mykiss.

Stress is conditioning animal welfare by negatively affecting a wide range of physiological and behavioral functions. This may be applied to circadian physiology and food intake. Cortisol, the stress-related hormone, may mediate such effect of stress, but other indirect mediators might be considered, such as sirtuin1. Then, either the independent modulatory effect or the existence of any interaction between mediators may be responsible. The circadian system is the main modulator of several integrative mechanisms at both central and peripheral levels that are rhythmically presented, thus influencing different processes such as food intake. In this way, food intake is controlled by the circadian system, as demonstrated by the persistence of such rhythms of food intake in the absence of environmental external cues. Our study aimed to evaluate the daily profile of hypothalamic mRNA abundance of circadian clock genes (clock1a, bmal1, per1 and rev-erbß-like), and food intake regulators (crf, pomc-a1, cart, and npy) in rainbow trout (Oncorhynchus mykiss), the impact of stress on such rhythms, and the involvement of cortisol and sirtuin1 as mediators. Four cohorts of trout were subjected to 1) normal stocking density (control group), 2) high stocking density for 72 hours (stress group), 3) normal stocking density and implanted with mifepristone, a glucocorticoid receptors antagonist, and 4) mifepristone administered and stressed for 72 hours. Fish from each group were sampled every 4-h along the 24-h LD cycle, and cortisol, glucose and lactate plasma levels were evaluated. Hypothalamic mRNA abundance of clock genes, food intake regulators, glucocorticoid receptors and sirtuin1 were qPCR assayed. Our results reveal the impact of stress on most of the genes assayed, but different mechanisms appear to be involved. The rhythm of clock genes displayed decreased amplitude and averaged levels in stressed trout, with no changes of the acrophase being observed. This effect was not prevented by mifepristone. On the contrary, the effect of stress on the daily profile of crf, pomc-a1, and npy was totally prevented by mifepristone administration. Accordingly, cortisol appears to mainly mediate the effect of stress on food intake regulators through binding to specific glucocorticoid receptors within trout hypothalamus, whereas sirtuin1 is apparently mediating such effects on the circadian system in the same brain region. Further research must be performed to clarify those mechanisms through which stress influences food intake and the circadian oscillator within the same brain region, hypothalamus, in rainbow trout, and the interaction among them all.

Impact of Air Exposure on Vasotocinergic and Isotocinergic Systems in Gilthead Sea Bream (Sparus aurata): New Insights on Fish Stress Response.

The hypothalamus-pituitary-interrenal (HPI) and hypothalamus-sympathetic-chromaffin cell (HSC) axes are involved in the regulation of the stress response in teleost. In this regard, the activation of a complex network of endocrine players is needed, including corticotrophin-releasing hormone (Crh), Crh binding protein (Crhbp), proopiomelanocortin (Pomc), thyrotropin-releasing hormone (Trh), arginine vasotocin (Avt), and isotocin (It) to finally produce pleiotropic functions. We aimed to investigate, using the gilthead sea bream (Sparus aurata) as a biological model, the transcriptomic response of different endocrine factors (crh, crhbp, pomcs, trh), neuropeptides (avt and it), and their specific receptors (avtrv1a, avtrv2, and itr) in four important target tissues (hypothalamus, pituitary, kidney and liver), after an acute stress situation. We also investigated several stress hormones (catecholamines and cortisol). The stress condition was induced by air exposure for 3 min, and hormonal, metabolic and transcriptomic parameters were analyzed in a time course response (15 and 30 min, and 1, 2, 4, and 8 h post-stress) in a total of 64 fish (n = 8 fish per experimental group; p = 0.05; statistical power = 95%). Our results showed that plasma noradrenaline, adrenaline and cortisol values increased few minutes after stress exposure. At hypothalamic and hypophyseal levels, acute stress affected mRNA expression of all measured precursors and hormonal factors, as well as their receptors (avtrs and itr), showing the activation, at central level, of HPI, HSC, and Avt/It axes in the acute stress response. In addition, stress response also affected mRNA levels of avtrs and itr in the head kidney, as well as the steroidogenic acute regulatory protein (star) and tyrosine hydroxylase (th) expression, suggesting their participation in the HPI and HSC axes activation. Moreover, the pattern of changes in hepatic avtrs and itr gene expression also highlights an important role of vasotocinergic and isotocinergic pathways in liver metabolic organization after acute stress events. Our results demonstrate, both at transcriptional and circulating levels of several hormones, the existence of a complex activation of different endocrine pathways in S. aurata related to the stress pathways, where vasotocinergic and isotocinergic systems can also be considered key players of the acute stress response orchestration.

The Impact of CRISPR-Cas System on Antiviral Therapy.

Clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein nuclease (Cas) is identified as an adaptive immune system in archaea and bacteria. Type II of this system, CRISPR-Cas9, is the most versatile form that has enabled facile and efficient targeted genome editing. Viral infections have serious impacts on global health and conventional antiviral therapies have not yielded a successful solution hitherto. The CRISPR-Cas9 system represents a promising tool for eliminating viral infections. In this review, we highlight 1) the recent progress of CRISPR-Cas technology in decoding and diagnosis of viral outbreaks, 2) its applications to eliminate viral infections in both pre-integration and provirus stages, and 3) various delivery systems that are employed to introduce the platform into target cells.

Influence of light and food on the circadian clock in liver of rainbow trout, Oncorhynchus mykiss.

Several reports support the existence of multiple peripheral oscillators in fish, which may be able to modulate the rhythmic functions developed by those tissues hosting them. Thus, a circadian oscillator has been proposed to be located within fish liver. In this vertebrate group, the role played by the circadian system in regulating metabolic processes in liver is mostly unknown. We, therefore investigated the liver of rainbow trout (Oncorhynchus mykiss) as a potential element participating in the regulation of circadian rhythms in fish by hosting a functional circadian oscillator. The presence and expression pattern of main components of the circadian molecular machinery (clock1a, bmal1, per1 and rev-erbß-like) were assessed. Furthermore, the role of environmental cues such as light and food, and their interaction in order to modulate the circadian oscillator was also assessed by exposing animals to constant conditions (absence of light for 48 h, and/or a 4 days fasting period). Our results demonstrate the existence of a functional circadian oscillator within trout liver, as demonstrated by significant rhythms of all clock genes assessed, independently of the environmental conditions studied. In addition, the daily profile of mRNA abundance of clock genes is influenced by both light (mainly clock1a and per1) and food (rev-erbß-like), which is indicative of an interaction between both synchronizers. Our results point to rev-erbß-like as possible mediator between the influence of light and food on the circadian oscillator within trout liver, since its daily profile is influenced by both light and food, thus affecting that of bmal1.

Daily rhythms in activity and mRNA abundance of enzymes involved in glucose and lipid metabolism in liver of rainbow trout, Oncorhynchus mykiss. Influence of light and food availability.

The present research aimed to investigate in a model of teleost fish (rainbow trout) the existence of daily changes in activity and mRNA abundance of several proteins involved in major pathways of carbohydrate and lipid metabolism in liver, and to test whether or not both the light-dark cycle and food availability might influence such rhythms. For this purpose, four cohorts of animals previously adapted to normal housing conditions (12L:12D; Lights on at ZT0; feeding time at ZT2) were subjected to: normal conditions (LD); 48-h constant darkness (DD); 96-h food deprivation (LD + Fasting); or constant darkness and food deprivation (DD + Fasting) respectively. After such time periods, fish were sacrificed and sampled every 4-h on the following 24-h period (ZT/CT0, 4, 8, 12, 16, 20 and 0'). Our results reveal that cortisol and all the analysed genes (gk, pepck, g6pase, pk, glut2, hoad and fas) exhibited well defined daily rhythms, which persisted even in the absence of light and/or food indicating the endogenous nature of such rhythms. Even when the variations of enzyme activities were not significant, their rhythms mostly paralleled those of the respective gene expression. The rhythms of mRNA abundance were apparently dependent on the presence of food, but the light/dark cycle also influenced such rhythms. Since cortisol does not appear to be mainly involved in generating such daily rhythms in liver, alternative mechanisms might be involved, such as a direct interaction between metabolism and the circadian system.