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Bimetallic core–shell nanoparticle arrays at liquid–liquid interface for the degradation and monitoring of dye pollutants in situ by SERS.

Accumulating data have demonstrated that shift work causes a disturbance in circadian rhythms, which is detrimental to physiology and performance. However, the detailed effects of shift work and especially the underlying mechanisms remain to be further investigated. Frequently shifting schedules are widely used in industries, e.g., maritime tasks, oil mining, and aviation. In this work, we investigated the physiological changes and vigilance of 12 subjects who lived on a 30-day frequent shift working schedule in a confined environment, which mimics the common maritime schedules. Elevated and decreased cortisol levels were observed at different stages during the shift, suggesting the occurrence of stress and fatigue. The results of the Karolinska Sleepiness Scale (KSS) indicate increased sleepiness and a changed pattern of the rhythmicity of sleepiness during the shift. The tests of the Psychomotor Vigilance Task (PVT) reveal that the shift led to a continuously decreasing alertness as the shift working schedule progressed, which is prevalently due to the increasingly slower reaction speed. The PVT time-out errors were significantly increased in the early period but decreased in the late period. In addition, we found recoupling of the correlations between multiple physiological and cognitive variables. For instance, heartbeat rate (HR) and breath rate (BR) showed moderate correlations in the control and early periods but little in the late period. Together, these results reveal substantial alterations in diurnal rhythms, affected vigilance and changed coupling of the correlations of diurnal rhythms, physiology and cognition caused by a shift schedule. Our findings may help in the recognition of the detrimental effects of such working schedules and provide clues for the development of potential mitigations.

Circadian clocks are evolved to adapt to the daily environmental changes under different conditions. The ability to maintain circadian clock functions in response to various stresses and perturbations is important for organismal fitness. Here, we show that the nutrient-sensing GCN2 signaling pathway is required for robust circadian clock function under amino acid starvation in Neurospora. The deletion of GCN2 pathway components disrupts rhythmic transcription of clock gene frq by suppressing WC complex binding at the frq promoter due to its reduced histone H3 acetylation levels. Under amino acid starvation, the activation of GCN2 kinase and its downstream transcription factor CPC-1 establish a proper chromatin state at the frq promoter by recruiting the histone acetyltransferase GCN-5. The arrhythmic phenotype of the GCN2 kinase mutants under amino acid starvation can be rescued by inhibiting histone deacetylation. Finally, genome-wide transcriptional analysis indicates that the GCN2 signaling pathway maintains robust rhythmic expression of metabolic genes under amino acid starvation. Together, these results uncover an essential role of the GCN2 signaling pathway in maintaining the robust circadian clock function in response to amino acid starvation, and demonstrate the importance of histone acetylation at the frq locus in rhythmic gene expression.

Circadian clocks control the physiological and behavioral rhythms to adapt to the environment with a period of ~24 h. However, the influences and mechanisms of the extreme light/dark cycles on the circadian clock remain unclear. We showed that, in Neurospora crassa, both the growth and the microconidia production contribute to adaptation in LD12:12 (12 h light/12 h dark, periodically). Mathematical modeling and experiments demonstrate that in short LD cycles, the expression of the core clock protein FREQUENCY was entrained to the LD cycles when LD > 3:3 while it free ran when T ≤ LD3:3. The conidial rhythmicity can resonate with a series of different LD conditions. Moreover, we demonstrate that the existence of unknown blue light photoreceptor(s) and the circadian clock might promote the conidiation rhythms that resonate with the environment. The ubiquitin E3 ligase FWD-1 and the previously described CRY-dependent oscillator system were implicated in regulating conidiation under short LD conditions. These findings shed new light on the resonance of Neurospora circadian clock and conidiation rhythms to short LD cycles, which may benefit the understandings of both the basic regulatory aspects of circadian clock and the adaptation of physiological rhythms to the extreme conditions.

The circadian clock plays a critical role in synchronizing the inner molecular, metabolic and physiological processes to environmental cues that cycle with a period of 24 h. Non-24 h and shift schedules are commonly used in maritime operations, and both of which can disturb circadian rhythms. In this study, we first conducted an experiment in which the volunteers followed a 3-d rotary schedule with consecutive shift in sleep time (rotatory schedule), and analyzed the changes in salivary cortisol rhythms and blood variables. Next we conducted another experiment in which the volunteers followed an 8 h-on and 4-h off schedule (non-24-h schedule) to compare the changes in blood/serum variables. The rotatory schedule led to elevated levels of serum cortisol during the early stage, and the phase became delayed during the early and late stages. Interestingly, both of the schedules caused comprehensive changes in blood/serum biochemical variables and increased phosphate levels. Furthermore, transcriptomic analysis of the plasma miRNAs from the volunteers following the rotatory schedule identified a subset of serum miRNAs targeting genes involved in circadian rhythms, sleep homeostasis, phosphate transport and multiple important physiological processes. Overexpression of miRNAs targeting the phosphate transport associated genes, SLC20A1 and SLC20A2, showed altered expression due to rotary schedule resulted in attenuated cellular levels of phosphate, which might account for the changed levels in serum phosphate. These findings would further our understanding of the deleterious effects of shift schedules and help to optimize and enhance the performances and welfare of personnel working on similar schedules.

The composition and function of intestinal microbial communities are important for human health. However, these intestinal floras are sensitive to changes in the environment. Adverse changes to intestinal flora can affect the health of astronauts, resulting in difficulties in implementing space missions. We randomly divided mice into three groups and placed each group in either a normal environment, simulated microgravity environment or a combined effects environment, which included simulated microgravity, low pressure and noise. Fecal samples of the mice were collected for follow-up analysis based on metagenomics technology. With the influence of different space environmental factors, the species composition at the phylum and genus levels were significantly affected by the combined effects environment, especially the abundance of the Firmicutes and Bacteroidetes. Furthermore, screening was conducted to identify biomarkers that could be regarded as environmental markers. And there have also been some noticeable changes in the function of intestinal floras. Moreover, the abundance of antibiotic resistance genes (ARGs) was also found to be changed under different environmental conditions, such as bacitracin and vancomycin. The combined effects environment could significantly affect the species composition, function, and the expression of ARGs of intestinal flora of mice which may provide a theoretical basis for space medical supervision and healthcare.

Since 2019, COVID-19 began spreading globally and has significantly affected peoples’ daily lifestyles. The public was asked to stay at home for constant quarantine and community containment starting on 23 January 2020. To assess the circadian rhythms and sleep changes and their influential factors during the COVID-19 outbreak, a questionnaire was administered to 451 Chinese participants during 20–31 January 2020. The changes in circadian rhythm, sleep–wake cycle, dining, and exercise of the participants and their correlation with negative emotions were analyzed. Furthermore, the effects of three factors (holiday, quarantine, and concerns regarding the pandemic situation) on these changes were assessed. We found that 34.6% of the participants reported circadian rhythm disturbance. Moreover, 67.2% presented negative emotions (worry, fear, downheartedness, anxiety, depression, and stupefaction) regarding the pandemic situation, among which worry was the most prevalent. Gender and age were significant factors for changes in the circadian phases and emotions. There was a correlation between circadian rhythm alterations and negative emotions. In addition, holiday, quarantine, and concerns regarding the pandemic situation had significant effects on circadian rhythms and sleep in a substantial part of the population. Regression analysis demonstrated reciprocal influences between many of these variables. Our findings suggest that circadian rhythms, sleep, and negative emotions in the normal population need to be considered during the pandemic period and that the adjustment of circadian rhythms could help promote sleep, restore emotions and improve public health.

To survive in an ever-changing world we need to learn and memorize associations of environmental stimuli and generalize them to new situations. Both memory and generalization critically rely on the hippocampus, but it is unclear how hippocampal neuronal activities represent memory and generalization, and if a conserved hippocampal mechanism serves these functions. Here we compared neuronal activities in hippocampal CA1 region of two sub-strains of the widely used C57BL/6 mice, C57BL/6J (B6J) and C57BL/6NCrl (B6NCrl), in contextual fear conditioning. Both sub-strains learnt well but differed in freezing and generalization. They displayed distinct early-late bi-phasic reactions to the unconditioned stimulus. While in both sub-strains the neurons showing late-phase reactions were preferentially engaged in memory representation, the neuronal activity feature that correlated with generalization level differed in the two sub-strains: in B6NCrl, these neurons’ activity level during learning negatively correlated with the generalization level; in B6J, functional coupling of these late-phase neurons with other neurons positively correlated with the generalization level. We further found that the distinct neuronal reactions were accompanied by distinct GABAb receptor-mediated inhibition but not by differences in the major synaptic inputs or neuronal excitability of the CA1. Therefore, this comparative study reveals two signature neuronal activity features in learning that can predict generalization levels. The results also demonstrate that differences in hippocampal network properties lead to diverse hippocampal mechanisms in memory encoding and generalization.

Increasing evidence has pointed to the connection between pre-mRNA splicing and the circadian clock; however, the underlying mechanisms of this connection remain largely elusive. In the filamentous fungus Neurospora crassa, the core circadian clock elements comprise White Collar 1 (WC-1), WC-2 and FREQUENCY (FRQ), which form a negative feedback loop to control the circadian rhythms of gene expression and physiological processes. Previously, we have shown that in Neurospora, the pre-mRNA splicing factors Pre-mRNA-processing ATP-dependent RNA helicase 5 (PRP5), protein arginine methyl transferase 5 (PRMT5) and snRNA gene U4-2 are involved in the regulation of splicing of frq transcripts, which encode the negative component of the circadian clock system. In this work we further demonstrated that repression of spliceosomal component sRNA genes, U5, U4-1, and prp5, affected the circadian conidiation rhythms. In a prp5 knockdown strain, the molecular rhythmicity was dampened. The expression of a set of snRNP genes including prp5 was up-regulated in a mutant strain lacking the clock component wc-2, suggesting that the function of spliceosome might be under the circadian control. Among these snRNP genes, the levels of prp5 RNA and PRP5 protein oscillated. The distribution of PRP5 in cytosol was rhythmic, suggesting a dynamic assembly of PRP5 in the spliceosome complex in a circadian fashion. Silencing of prp5 caused changes in the transcription and splicing of NCU09649, a clock-controlled gene. Moreover, in the clock mutant frq9, the rhythmicity of frq I-6 splicing was abolished. These data shed new lights on the regulation of circadian clock by the pre-RNA splicing, and PRP5 may link the circadian clock and pre-RNA splicing events through mediating the assembly and function of the spliceosome complex.

Most organisms on Earth possess circadian rhythms in their physiology and behaviors that allow them to resonate with the cycling environment over a 24-h period. However, in human society, a substantial quantity of jobs requires non-24-h working and rest or shift schedules, which causes more or less misalignment in circadian rhythms and disorders as a consequence. In this work, we conducted a sleep deprivation (SD) and non-24-h working and rest schedule (8 h on and 4 h off) experiment over 10 d in total and measured the changes in a series of physiologic and cognitive parameters. The results show that although the subjects could sleep during the schedule, their sleepiness increased significantly. Actigraphy data suggest that a 12-h schedule might result in chronic SD. Along with the increased sleepiness revealed by the Karolinska Sleepiness Scale questionnaire, the neurobehavioral psychomotor vigilance test data reveal that, compared with the control period, the reaction time of the subjects was significantly delayed. The saliva insulin levels were significantly changed in the morning in SD and non-24-h cycles. Salivary biochemical parameters were also altered, including aspartate aminotransferase and K

Backgroundhe circadian clock extensively regulates physiology and behavior. In space, the astronauts encounter many environmental factors that are dramatically different from those on earth, however, the effects of these factors on circadian rhythms and the mechanisms remain largely unknown. The present study aimed to investigate the changes in the mouse circadian rhythm and gut microbiome under simulated space capsule conditions, including microgravity, noise and low atmospheric pressure.ResultsNoise and low atmospheric pressure were loaded in the capsule while the conditions in the animal room remained constant. The mice in the capsule showed disturbed locomotor rhythms and faster adaptation to a 6-h phase advance. RNA sequencing of hypothalamus samples revealed that microgravity simulated by hind limb unloading (HU) and exposure to noise and low atmospheric pressure led to decreases in the quantities of differentially expressed genes (DEGs), including circadian clock genes. Changes in the rhythmicity of genes implicated in pathways of cardiovascular deconditioning and more concentrated circadian phases were found under HU or noise and low atmospheric pressure. Furthermore, 16S rRNA sequencing revealed dysbiosis in the gut microbiome, and noise and low atmospheric pressure may repress the temporal discrepancy in the microbiome community structure induced by microgravity. Changes in diel oscillation were observed in a number of gut bacteria with critical physiological consequences in metabolism and immunodefense.ConclusionsOur data demonstrate that in addition to microgravity, exposure to noise and low atmospheric pressure affect the robustness of circadian rhythms and the community structure of the gut microbiome, and these factors may interfere with each other in their adaptation to respective conditions. These findings are important to further our understanding of the alteration of circadian rhythms in the space complex environment.

Background: The composition and function of intestinal microbial communities are important for human health. However, these intestinal floras are sensitive to changes in the environment. Adverse changes to intestinal flora can affect the health of astronauts in complex space environments, resulting in difficulties of implementing space missions.Results: Under the influence of different space environmental factors, the species composition at the phylum and genus level were significantly affected by the combined effects environment. Furthermore, screening was conducted to identify biomarkers that could be regarded as environmental markers. And there have also been some noticeable changes in the function of intestinal floras. Moreover, the antibiotic resistance genes (ARGs) were also found to be differently expressed under different environmental conditions.Conclusion: The combined effects environment could significantly affect the species composition, function and the expression of ARGs of intestinal flora which may provide a theoretical basis for space medical supervision and healthcare. Meanwhile, these changes require more attention because they may induce diseases that may further affect performance during space missions.

Introduction: From December 2019, COVID-19 (novel coronavirus pneumonia) began spreading in China and has significantly affected the industrial economy and peoples’ daily lifestyle. Beginning on January 23, the public was asked to constantly stay at home for quarantine and community containment.Methods: To assess the effects of the changes in diel rhythms and sleep and their association with negative emotions during the COVID-19 outbreak, a questionnaire was administered to 451 responders for analysis between January 20, 2020, and January 31, 2020, in China.Results: We found that 34.6% of the participants reported diel rhythm disturbance. Moreover, 67.2% of the participants presented negative emotions regarding the pandemic situation, including worry, fear, downheartedness, anxiety, depression, and stupefaction; among them, worry was the most prevalent. Gender and age were significant factors for changes in the diel phases and emotions. There was a correlation between diel rhythm alterations and negative emotions. Three factors, i.e., the Spring Festival holiday, quarantines and concern regarding the pandemic situation, were associated with changes in diel rhythms, sleep, and negative emotions during the pandemic period. Holiday jet lag, quarantine (or community containment), and concerns regarding the pandemic situation had significant effects on diel rhythms, sleep and negative emotion in a substantial part of the population. Conclusions: Our findings suggest that diel rhythms and sleep and their association with negative emotions in COVID-19 patients and the normal population need to be considered. Moreover, the adjustment of diel rhythms could help relieve negative effects and improve the global health during the pandemic period.

Circadian clocks have important physiological and behavioral functions in humans and other organisms, which enable organisms to anticipate and respond to periodic environmental changes. Disturbances in circadian rhythms impair sleep, metabolism, and behavior. People with jet lag, night workers and shift workers are vulnerable to circadian misalignment. In addition, non-24-h cycles influence circadian rhythms and cause misalignment and disorders in different species, since these periods are beyond the entrainment ranges. In certain special conditions, e.g., on submarines and commercial ships, non-24-h watch schedules are often employed, which have also been demonstrated to be deleterious to circadian rhythms. Personnel working under such conditions suffer from circadian misalignment with their on-watch hours, leading to increased health risks and decreased cognitive performance. In this review, we summarize the research progress and knowledge concerning circadian rhythms on submarines and other environments in which non-24-h watch schedules are employed.

Sleep loss is one of large challenges during space missions. A variety of sleep problems have been shown in space. We aimed to further characterize more representative and consecutive sleep-wake pa...

The circadian clock is an endogenous, self-sustained biological rhythm. Different organisms possess different period of the circadian clock, ranging from 20 to 28 h. Synchronizations of the circadian clock contribute to the organisms’ fitness. This synchrony refers not only to the synchronization between the body clock and the environment, but also to that between the central and peripheral clocks. The synchronization is a process that the organism’s circadian clock is reset by the outside environment. Being synchronized often makes the organism oscillate in a period of 24 h, that of the earth’s rotation. More importantly, being synchronized changes the phase of the organism’s clock, for example activity onset, to a stable phase relationship to the environmental time cues, like the sunrise. Pittendrigh had raised the phase response curve (PRC) model to explain how light synchronizes the circadian clock by phase shifting the clock. His PRC model successfully predicts entrainment on the basis of period changes. Light pulse is considered as the most effective zeitgeber that can synchronize an organism’s circadian clock. Phase response curves show distinct similarities from diverse organisms, including both diurnal and nocturnal animals. Better understanding on these synchronizations are built on recent advances in the following aspects, the molecular feedback loops, the novel photoreceptor melanopsin and its expressing cells, and the hierarchical structures constituting the mammalian clock system. This review summarizes recent progresses on topics of the synchronizations of both the body clock and the environment, and the central and peripheral clocks. It discusses how light and food cues mediate the synchronization of the clock system, followed with introducing main human disorders in which desynchronized body clocks are involved. Light pulse transmits the environmental time cues to the suprachiasmatic nucleus (SCN) through the retino-hypothalamic tract (RHT). SCN is located in the hypothalamus and serves as the central oscillator in mammals. Food is another important zeitgeber that synchronizes the circadian clock. Feeding behavior passes the timing information to the central oscillator, SCN, by taking advantages of the circulating hormones and metabolites. After receiving information from either light or food, SCN integrates the information and passes them along to peripheral clocks that locate in different organs, finally reaching to a coherent circadian system for the entire multicellular organism. Therefore, this review offers basic knowledge to further researches on the clock synchronization, and expects people understand that keeping our body clocks in synchrony is important to our health.

Nonsense-mediated RNA decay (NMD) is a crucial post-transcriptional regulatory mechanism that recognizes and eliminates aberrantly processed transcripts, and mediates the expression of normal gene transcripts. In this study, we report that in the filamentous fungus Neurospora crassa, the NMD factors play a conserved role in regulating the surveillance of NMD targets including premature termination codon (PTC)-containing transcripts and normal transcripts. The circadian rhythms in all of the knockout strains of upf1-3 genes, which encode the Up-frameshift proteins, were aberrant. The upf1 knockout strain displays a shortened circadian period, which can be restored by constantly expressing exogenous Up-frameshift protein 1 (UPF1). UPF1 regulates the circadian clock by modulating the splicing of the core clock gene frequency (frq) through spliceosome and spliceosome-related arginine/serine-rich splicing factors, which partly account for the short periods in the upf1 knockout strain. We also demonstrated that the clock genes including White Collar (WC)-1, WC-2, and FRQ are involved in controlling the diurnal growth rhythm, and UPF1 may affect the growth rhythms by mediating the FRQ protein levels in the daytime. These findings suggest that the NMD factors play important roles in regulating the circadian clock and diurnal growth rhythms in Neurospora.

Circadian clocks control the physiological and behavioral daily rhythms to adapt to the changing environment with a period of ~24 h. However, the influence and mechanism of extreme light-dark cycles on the circadian clock remain unclear. We show that, in the fungus Neurospora crassa under short LD cycles, both the growth rate and the ratio of microconidia production contributes to adaptation in LD12:12 (light for 12 h and dark for 12 h, periodically). Mathematical modeling and experiments demonstrate that in short LD cycles, the expression of the core clock protein FREQUENCY is entrained to the LD cycles when LD>3:3 while it free runs when T≤ LD3:3. We investigated the changes in circadian/diurnal rhythms under a series of different LD conditions, and the results showed that conidial rhythmicity can be adapted to the short LD cycles. We further demonstrate that the existence of unknown blue light photoreceptor(s) and the circadian clock might promote the conidiation rhythms that resonate with the environment. A high-intensity light induced the expression of a set of downstream genes involved in various metabolic pathways. The ubiquitin E3 ligase FWD-1 and the previously described CRY-dependent oscillator system were implicated in regulating conidiation under short LD conditions.

In space, circadian rhythms are prone to alteration. Head-down (–6°) bed rest (HDBR) is an approach simulating the weightlessness condition, which allows effects of weightlessness on physiological variables to be studied on the ground. In this work, we analyzed the changes in diurnal rhythms of activity, sleep-wake cycles, and cardiovascular responses in a 45-day HDBR. All subjects exhibited increased daytime sleep, whereas the total sleep time was comparable. The results of wrist activity monitoring showed a significant reduction during HDBR and recovery after HDBR. Moreover, changes in the average frequency, amplitude, and phase of heart rate were observed. Analysis of heart rate variability showed a decrease in both high-frequency and low-frequency power after HDBR. Together, these data demonstrate that HDBR can alter the diurnal rhythms of a number of physiological processes, some of which might be attributed to reduction in activity of the autonomic nervous system.

In the Neurospora circadian negative feedback loop, white collar 1 (WC-1) and WC-2 form the WC complex that activates frequency (frq) transcription. Here we show that Not1 is a WC-interacting protein and is important for maintaining WC levels. The not1 transcript displays a circadian oscillation with a similar phase as frq. Down-regulation of not1 leads to low levels of WC-1 and WC-2 and a delayed circadian phase as a result of increased protein degradation and increased WC activity. Protein purification of Not1 shows that it is part of the Neurospora Ccr4-Not complex. ccr4 is a clock-controlled gene and is regulated directly by the WC complex. Down-regulation of ccr4 results in a phase delay and period lengthening of the clock. Together, our findings suggest that the Ccr4-Not complex participates in the Neurospora clock function by interacting with and regulating the WC complex.

Circadian clocks are internal molecular time-keeping mechanisms that enable organisms to adjust their physiology and behavior to the daily surroundings. Misalignment of circadian clocks leads to both physiological and health impairment. Post-transcriptional regulation and translational regulation of circadian clocks have been extensively investigated. In addition, accumulating evidence has shed new light on the involvement of ribonucleoprotein complexes (RNPs) in the post-transcriptional regulation of circadian clocks. Numerous RNA-binding proteins (RBPs) and RNPs have been implicated in the post-transcriptional modification of circadian clock proteins in different model organisms. Herein, we summarize the advances in the current knowledge on the role of RNP complexes in circadian clock regulation.

Codon-usage bias has been observed in almost all genomes and is thought to result from selection for efficient and accurate translation of highly expressed genes. Codon usage is also implicated in the control of transcription, splicing and RNA structure. Many genes exhibit little codon-usage bias, which is thought to reflect a lack of selection for messenger RNA translation. Alternatively, however, non-optimal codon usage may be of biological importance. The rhythmic expression and the proper function of the Neurospora FREQUENCY (FRQ) protein are essential for circadian clock function. Here we show that, unlike most genes in Neurospora, frq exhibits non-optimal codon usage across its entire open reading frame. Optimization of frq codon usage abolishes both overt and molecular circadian rhythms. Codon optimization not only increases FRQ levels but, unexpectedly, also results in conformational changes in FRQ protein, altered FRQ phosphorylation profile and stability, and impaired functions in the circadian feedback loops. These results indicate that non-optimal codon usage of frq is essential for its circadian clock function. Our study provides an example of how non-optimal codon usage functions to regulate protein expression and to achieve optimal protein structure and function.

Many aspects of energy metabolism, including glucose and lipid homeostasis and mitochondrial oxidative metabolism, are under precise control by the mammalian circadian clock. However, the molecular mechanism for coordinate integration of the circadian clock and various metabolic pathways is poorly understood. Here we show that BAF60a, a chromatin-remodeling complex subunit, is rhythmically expressed in the liver of mice. Mice with liver-specific knockdown of BAF60a show abnormalities in the rhythmic expression pattern of clock and metabolic genes and in the circulating metabolite profile. Consistently, knockdown of BAF60a impairs the oscillation of clock genes in serum-shocked HepG2 cells. At the molecular level, BAF60a activates Bmal1 and G6Pase transcription by way of the coactivation of retinoid-related orphan receptor alpha (RORα). In addition, BAF60a is present near ROR response elements (RORE) on the proximal Bmal1 and G6Pase promoters and turns the chromatin structure into the active state. Conclusion: Our data suggest a critical role for BAF60a in the coordinated regulation of hepatic circadian clock and energy metabolism in mammals. (HEPATOLOGY 2011;)

FREQUENCY (FRQ) is the central component of the Neurospora circadian clock. All FRQ proteins form the FFC complex with FRH (FRQ-interacting RNA helicase) that acts as the negative element in the circadian negative feedback loop by repressing frq mRNA levels. To understand the function of the FRQ-FRH interaction, we mapped and identified the minimal FRQ region that is required for FRQ-FRH interaction. We demonstrated that the FRQ-FRH complex formation is required for the interaction between FRQ and the White Collar Complex (WCC) and clock function. On the other hand, in the FRQ-FRH complex, FRQ is also required for the FRH-WCC interaction. Disruption of FRQ-FRH interaction or down-regulation of FRH results in hypophosphorylation, rapid degradation of FRQ, as well as low levels of WHITE COLLAR-1 and WHITE COLLAR-2. Furthermore, we showed that the rapid FRQ degradation in the absence of FRH is independent of FWD-1, the ubiquitin E3 ligase of FRQ under normal conditions, thus uncovering an alternative pathway for FRQ degradation.

The eukaryotic circadian oscillators consist of autoregulatory negative feedback loops. However, little is known about the role of post-transcriptional regulation of RNA in circadian oscillators. In the Neurospora circadian negative feedback loop, FRQ and FRH form the FFC complex that represses frq transcription. Here we show that FFC also binds frq RNA and interacts with the exosome to regulate frq RNA decay. Consequently, frq RNA is robustly rhythmic as it is more stable when FRQ levels are low. Silencing of RRP44, the catalytic subunit of the exosome, elevates frq RNA levels and impairs clock function. In addition, rrp44 is a clock-controlled gene and a direct target of the WHITE COLLAR complex, and RRP44 controls the circadian expression of at least one ccg. Taken together, these results suggest that FFC and the exosome are part of a post-transcriptional negative feedback loop that regulates frq transcript levels and the circadian output pathway.

Human EFCBP/NECAB family consists of important participants in neuronal calcium signaling, including EFCBP1/NECAB1, EFCBP2/NECAB2 and EFCBP3/NECAB3. In the present study, we identified the full-length 5229 bp EFCBP1 cDNA which was not described before. Human EFCBP1 encodes a 351 amino acid protein containing two EF-hand motifs and an antibiotic biosynthesis monooxygenase (ABM) domain, sharing 49.9 and 56.8% global homology with human EFCBP2 and EFCBP3. Northern hybridization revealed that EFCBP1 is specifically expressed in brain and its abundance varies in different brain regions. EFCBP1's abundance in temporal lobe, frontal lobe and occipital pole is about 3.4, 1.9 and 1.5 folds of the average abundance in cerebral cortex, respectively. The expression level of EFCBP1 equals in putamen and cerebral cortex, while no hybridization signal was detected in spinal cord. In addition, we found that EFCBP1, EFCBP2 and EFCBP3 share a similar exon distribution mode, though their chromosomal localizations, genomic sizes and intron sizes are diverse.

The exosome is a complex with exoribonuclease activity that regulates RNA surveillance and turnover. The exosome also plays a role in regulating the degradation of precursor mRNAs to maintain the expression of splicing variants. In Neurospora, the silencing of rrp44, which encodes the catalytic subunit of the exosome, changed the expression of a set of spliceosomal snRNA, snRNP genes and SR protein related genes. The knockdown of rrp44 also affected the assembly of the spliceosome. RNA-seq analysis revealed a global change in bulk splicing events. Exosome-mediated splicing may regulate alternative splicing of NCU05290, NCU07421 and the circadian clock gene frequency (frq). The knockdown of rrp44 led to an increased ratio of splicing variants without intron 6 (I-6) and shorter protein isoform small FRQ (s-FRQ) as a consequence. These findings suggest that the exosome controls splicing events by regulating the degradation of precursor mRNAs and the gene expression, assembly and function of the spliceosome.

Gravity is one of the important environmental factors that influence the physiologies and behaviors of animals and humans, and changes in gravity elicit a variety of physiological and behavioral alterations that include impaired movement coordination, vertigo, spatial disorientation, and perceptual illusions. To elucidate the effects of gravity on human physiology and behavior, we examined changes in wrist and trunk activities and heart rate during parabolic flight and the activity of wrist and trunk in water immersion experiments. Data from 195 person-time parabolas performed by eight subjects revealed that the trunk motion counts decreased by approximately half during ascending legs (hypergravity), relative to the data acquired before the parabolic flights. In contrast, the wrist activity remained unchanged. The results from the water immersion experiments demonstrated that in the underwater condition, both the wrist and trunk activities were significantly decreased but the latter decreased to a much lower level. Together, these data suggest that gravitational alterations can result in differential influences on the motions of the wrist and the trunk. These findings might be important for understanding the degeneration of skeleton and muscular system and performance of astronauts in microgravity.

Here, we report the identification of a novel domain – GG (domain in KIAA1199, FAM3, POMGnT1 and Tmem2 proteins, with two well-conserved glycine residues), present in eukaryotic FAM3 superfamily (FAM3A, FAM3B, FAM3C and FAM3D), POMGnT1 (protein O-linked mannose β-1,2-N-acetylglucosaminyltransferase), TEM2 proteins as well as phage gp35 proteins. GG domain has been revealed to be implicated in muscle–eye–brain disease and non-syndromic hearing loss. The presence of GG domain in Bacteriophage gp35 hinge connector of long tail fiber might reflect the horizontal gene transfer from organisms. And we proposed that GG domain might function as important structural element in phage LTF.

Natural antisense transcripts (NATs), also named endogenous antisense transcripts, are a class of genes whose role in controlling gene expression is becoming more and more relevant. NATs might play important roles in gene expression and translation regulation. Present work investigated the presence of NATs of Alzheimer's disease associated genes including PRESENILIN1, PRESENILIN2, BACE1, BACE2, APP, APOE, TAU (MAPT), PRION, alpha-SYNUCLEIN (SNCA), NICASTRIN, PEN2, APH1A, APH1B as well as CD147 (BASIGIN), and the results revealed that APP, BACE2, APH1A, TAU, CD147 and alpha-SYNUCLEIN contain natural antisense transcripts. These NATs were characterized according to the sense-antisense overlapping information and potential functional mechanisms were proposed. Present findings provide preliminary but important information about transcription regulation of AD associated genes, which would further our understanding of the gene expression regulation of AD, and also suggest a novel potential strategy for the therapy of AD.

Deficiency of human glycerate kinase leads to d-glycerate acidemia/d-glyceric aciduria. Through PCR cloning assisted by in silico approach, we isolated the human glycerate kinase genes—Glycerate Kinase 1 (GLYCTK1) and its alternatively splicing variant—Glycerate Kinase 2 (GLYCTK2), which might be associated with d-glycerate acidemia/d-glyceric aciduria. The locus of GLYCTK gene is mapped to 3p21. PCR amplification in seventeen human tissue cDNAs revealed that both GLYCTK1 and GLYCTK2 are expressed widely almost in all these tissues. The expression of mouse Glyctk in various tissues was demonstrated by in situ hybridization. Both GLYCTK1 and GLYCTK2 proteins are localized in cytosol, and GLYCTK2 proteins are specifically localized in mitochondria. Present results revealed the characteristic expression pattern of murine Glyctk in neural system, skeleton muscle, supporting that glycerate kinase is implicated in d-glycerate acidemia/d-glyceric aciduria.

We report here the identification of a novel domain - DIM (N-terminal domain in bacterial membrane proteins and other proteins) present exclusively in bacterial species including mycobacteria, revealed by PSI-BLAST iterative searches. DIM comprises about 53 amino acids in length with conserved Leu, Ile and Gly residues. Secondary structure prediction indicated that this domain contains two alpha-helices. DIM occurs at the N-terminus of proteins, and was found particularly but not exclusively in proteins with a transmembrane domain, and also in proteins with a FHA domain or RPT repeats. DIM-containing proteins have been reported to be involved in pathogenicity, signal transduction or small solute transport.

The 1-Acylglycerolphosphate acyltransferase is crucial enzyme for synthesis of glycerolipids as well as triacylglylcerol biosynthesis in eukaryotes. Six members of 1-acyl-sn-glycerol-3-phosphate acyltransferase family in human have been described, which were AGPAT1, 2, 3, 4, 5 and 6. Here we report the cloning and characterization of another novel human 1-acyl-sn-glycerol-3-phosphate acyltransferase member AGPAT7 (1-acyl-sn-glycerol-3-phosphate acyltransferase 7) gene, which was mapped to human chromosome 15q14. The AGPAT7 cDNA is 1898 bp in length, encoding a putative protein with 524 amino acid residues, which contains an acyltransferase domain in 123–234 aa. RT PCR amplification in 18 human tissues indicated that human AGPAT7 gene was widely expressed in uterus, thymus, pancreas, skeletal muscle, bladder, stomach, lung and testis. AGPAT7 protein was mainly localized to the endoplasmic reticulum (ER) in Hela cells.