Synthesis and Characterizations of Novel bi-ligand TbEu(cpioa)phen Phosphors with High Quantum Efficiency for WLED Applications.

The hydrothermal method was employed to synthesize a novel bi-ligands LnMOF: Ln(cpioa)phen. The secondary ligand 1, 10-phen serves as a bridging agent to further facilitate energy transfer between Ln ions and the primary ligand H3cpioa. A comparison between Ln(cpioa) MOFs (Ln: Tb3+, Eu3+) and Ln(cpioa)phen MOFs (Ln: Tb3+, Eu3+) reveals that addition of the secondary ligand significantly improves the emission intensity by as high as almost 34 times. After detailed structural study, it is found that different Ln ions have the similar coordination in the Ln(cpioa)phen MOF. In addition, the chromaticity of Ln(cpioa)phen MOFs can be easily tuned by the amounts of doping Ln ions. La0.974Tb0.0255Eu0.0005(cpioa)phen MOF has a white emission with a CIE coordinate of (0.323, 0.343). Characterizations of corresponding LED devices show that device based on Ln(cpioa)phen MOF has better photoluminescence performances, which indicates that Ln(cpioa)phen MOF has great potential of for WLED applications.

A new perspective on contaminants as "activators": Aromatic amine groups promoted degradation of tetracycline by ferrate(VI).

Occasionally, our group found that the degradation of tetracycline by ferrate(VI) could be promoted by four co-exist contaminants, containing aromatic amines (ofloxacin, diatrizoic acid, sulfadiazine and alachlor). This study investigated the promotion of aromatic amine groups on tetracycline degradation by ferrate(VI) by using aniline as a model compound. The results implied that the presence of aniline increased the degradation rate of tetracycline by 2.76 times, and the enhancement was weakened gradually with the decrease of pH from 10 to 7.5. The generation of Fe(IV) and·OH by the reaction between ferrate(VI) and aniline was proposed to enhance the degradation of tetracycline, supported by quenching experiments, electron paramagnetic resonance (EPR) and theoretical calculations. A positive correlation was found between the rate constant of tetracycline degradation and the electron-donating ability of the substituted amines (quantified by the Hammett substituent constants). In addition, the degradation of tetracycline was remarkably inhibited by HA and some inorganic ions such as NO3-, SO42-, Cl-, Ca2+, and Mg2+, and the inhibition also happened in the Songhua River water and the secondary effluent. The present study provided an insight into the complex oxidation process for the degradation of micropollutants containing aromatic amine by ferrate in water treatment.

Multiplex influences on vigilance and biochemical variables induced by sleep deprivation.

Introduction: Sleep loss and sleep deprivation (SD) cause deleterious influences on health, cognition, mood and behaviour. Nevertheless, insufficient sleep and SD are prevalent across many industries and occur in various emergencies. The deleterious consequences of SD have yet to be fully elucidated. This study aimed to assess the extensive influences of SD on physiology, vigilance, and plasma biochemical variables. Methods: Seventeen volunteers were recruited to participate in a 32.5-h SD experiment. Multiple physiological and cognitive variables, including tympanic temperature, blood oxygen saturation (SaO2), and vigilance were recorded. Urinal/salivary samples were collected and subjected to cortisol or cortisone analysis, and plasma samples were subjected to transcriptomic analysis of circular RNA (circRNA) expression using microarray. Plasma neurotransmitters were measured by targeted metabolic analysis, and the levels of inflammatory factors were assessed by antibody microarray. Results: The volunteers showed significantly increased sleepiness and decreased vigilance during SD, and the changes in circadian rhythm and plasma biochemistry were observed. The plasma calcium (p = 0.0007) was induced by SD, while ischaemia-modified albumin (IMA, p = 0.0030) and total bile acid (TBA, p = 0.0157) decreased. Differentially expressed circRNAs in plasma were identified, which are involved in multiple signaling pathways including neuronal regulation and immunity. Accordingly, SD induced a decrease in 3-hydroxybutyric acid (3OBH, p = 0.0002) and an increase in thyroxine (T4, p < 0.0001) in plasma. The plasma anti-inflammatory cytokine IL-10 was downregulated while other ten inflammatory factors were upregulated. Conclusion: This study demonstrates that SD influences biochemical, physiological, cognitive variables, and the significantly changed variables may serve as candidates of SD markers. These findings may further our understanding of the detrimental consequence of sleep disturbance at multiple levels.

The Function, Regulation, and Mechanism of Protein Turnover in Circadian Systems in Neurospora and Other Species.

Circadian clocks drive a large array of physiological and behavioral activities. At the molecular level, circadian clocks are composed of positive and negative elements that form core oscillators generating the basic circadian rhythms. Over the course of the circadian period, circadian negative proteins undergo progressive hyperphosphorylation and eventually degrade, and their stability is finely controlled by complex post-translational pathways, including protein modifications, genetic codon preference, protein-protein interactions, chaperon-dependent conformation maintenance, degradation, etc. The effects of phosphorylation on the stability of circadian clock proteins are crucial for precisely determining protein function and turnover, and it has been proposed that the phosphorylation of core circadian clock proteins is tightly correlated with the circadian period. Nonetheless, recent studies have challenged this view. In this review, we summarize the research progress regarding the function, regulation, and mechanism of protein stability in the circadian clock systems of multiple model organisms, with an emphasis on Neurospora crassa, in which circadian mechanisms have been extensively investigated. Elucidation of the highly complex and dynamic regulation of protein stability in circadian clock networks would greatly benefit the integrated understanding of the function, regulation, and mechanism of protein stability in a wide spectrum of other biological processes.

Simulated space environmental factors of weightlessness, noise and low atmospheric pressure differentially affect the diurnal rhythm and the gut microbiome.

The circadian clock extensively regulates physiology and behavior. In space, 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 diurnal rhythm and gut microbiome under simulated space capsule conditions, including microgravity, noise and low atmospheric pressure (LAP). Noise and LAP 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 containing the suprachiasmatic nucleus (SCN) revealed that microgravity simulated by hind limb unloading (HU) and exposure to noise and LAP 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 phases were found under HU or noise and LAP. Furthermore, 16S rRNA sequencing revealed dysbiosis in the gut microbiome, and noise and LAP may repress the temporal discrepancy in the microbiome community structure induced by microgravity. Changes in diurnal oscillations were observed in a number of gut bacteria with critical physiological consequences on metabolism and immunodefense. We also found that the superimposition of noise and LAP may repress normal changes in global gene expression and adaptation in the gut microbiome. Our data demonstrate that in addition to microgravity, exposure to noise and LAP 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 for furthering our understanding of the alterations in circadian rhythms in the complex environment of space.

The nutrient-sensing GCN2 signaling pathway is essential for circadian clock function by regulating histone acetylation under amino acid starvation.

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.

Differential regulation of phosphorylation, structure, and stability of circadian clock protein FRQ isoforms.

Neurospora crassa is an important model organism for circadian clock research. The Neurospora core circadian component FRQ protein has two isoforms, large FRQ (l-FRQ) and small FRQ (s-FRQ), of which l-FRQ bears an additional N-terminal 99-amino acid fragment. However, how the FRQ isoforms operate differentially in regulating the circadian clock remains elusive. Here, we show l-FRQ and s-FRQ play different roles in regulating the circadian negative feedback loop. Compared to s-FRQ, l-FRQ is less stable and undergoes hypophosphorylation and faster degradation. The phosphorylation of the C-terminal l-FRQ 794-aa fragment was markedly higher than that of s-FRQ, suggesting the l-FRQ N-terminal 99-aa region may regulate the phosphorylation of the entire FRQ protein. Quantitative label-free LC/MS analysis identified several peptides that were differentially phosphorylated between l-FRQ and s-FRQ, which were distributed in FRQ in an interlaced fashion. Furthermore, we identified two novel phosphorylation sites, S765 and T781; mutations S765A and T781A showed no significant effects on conidiation rhythmicity, although T781 conferred FRQ stability. These findings demonstrate that FRQ isoforms play differential roles in the circadian negative feedback loop and undergo different regulations of phosphorylation, structure, and stability. The l-FRQ N-terminal 99-aa region plays an important role in regulating the phosphorylation, stability, conformation, and function of the FRQ protein. As the FRQ circadian clock counterparts in other species also have isoforms or paralogues, these findings will also further our understanding of the underlying regulatory mechanisms of the circadian clock in other organisms based on the high conservation of circadian clocks in eukaryotes.

Bimetallic core-shell nanoparticle arrays at liquid-liquid interface for the degradation and monitoring of dye pollutants in situ by surface-enhanced Raman spectroscopy.

In situ monitoring of chemical reactions has attracted great attention in many fields. Herein, we successfully in situ track the degradation reaction process of a dye pollutant, methylene blue (MB), on the liquid-liquid interface (LLI) of bimetallic gold core-silver shell nanoparticles (Au@AgNPs) by surface-enhanced Raman spectroscopy (SERS). The optimized LLI bimetallic array of Au50@Ag10NPs exhibits ultrahigh SERS enhancement and excellent catalytic activity. Results evidenced a detection limit of MB down to 1 ppb, and the degradation rate of Au@AgNPs was as high as 85.2% in 30 s, relying on the excellent self-healing properties of nanoarrays. Furthermore, as a practical SERS analyzer, the LLI bimetallic array was used to detect trace amounts of other harmful dyes, including Rhodamine 6G (R6G) and crystal violet (CV) in pure or complex media. Our LLI bimetallic array exhibits a new orientation for monitoring catalytic reactions involving highly toxic, hazardous, or costly targets in food security fields in the future.

Alpha-Hemolysin from Staphylococcus aureus Obstructs Yeast-Hyphae Switching and Diminishes Pathogenicity in Candida albicans.

The use of antibiotics can disrupt the body's natural balance and increase the susteptibility of patients towards fungal infections. Candida albicans is a dimorphic opportunistic fungal pathogen with niches similar to those of bacteria. Our aim was to study the interaction between this pathogen and bacteria to facilitate the control of C. albicans infection. Alpha-hemolysin (Hla), a protein secreted from Staphylococcus aureus, causes cell wall damage and impedes the yeast-hyphae transition in C. albicans. Mechanistically, Hla stimulation triggered the formation of reactive oxygen species that damaged the cell wall and mitochondria of C. albicans. The cell cycle was arrested in the G0/G1 phase, CDC42 was downregulated, and Ywp1 was upregulated, disrupting yeast hyphae switching. Subsequently, hyphae development was inhibited. In mouse models, C. albicans pretreated with Hla reduced the C. albicans burden in skin and vaginal mucosal infections, suggesting that S. aureus Hla can inhibit hyphal development and reduce the pathogenicity of candidiasis in vivo.

Comprehensive detrimental effects of a simulated frequently shifting schedule on diurnal rhythms and vigilance.

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 misalignment leads to changes in cortisol rhythms, blood biochemical variables and serum miRNA profiles.

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 effects of combined environmental factors on the intestinal flora of mice based on ground simulation experiments.

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.

The Resonance and Adaptation of Neurospora crassa Circadian and Conidiation Rhyth ms to Short Light-Dark Cycles.

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.

Circadian misalignment on submarines and other non-24-h environments - from research to application.

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.

Regulation of the Neurospora Circadian Clock by the Spliceosome Component PRP5.

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.

Sleep deprivation and a non-24-h working schedule lead to extensive alterations in physiology and behavior.

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+. 16S rRNA-based analysis of the salivary microbiota showed differentially changed patterns in bacteria composition and concentration. Together, these data demonstrate that an abnormal working and rest schedule might produce comprehensive interference with circadian rhythms, metabolism, and cognition.-Ma, H., Li, Y., Liang, H., Chen, S., Pan, S., Chang, L., Li, S., Zhang, Y., Liu, X., Xu, Y., Shao, Y., Yang, Y., Guo, J. Sleep deprivation and a non-24-h working schedule lead to extensive alterations in physiology and behavior.

Up-Frameshift Protein UPF1 Regulates Neurospora crassa Circadian and Diurnal Growth Rhythms.

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.

The exosome controls alternative splicing by mediating the gene expression and assembly of the spliceosome complex.

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.

Alterations in the heart rate and activity rhythms of three orbital astronauts on a space mission.

Environmental factors in space are dramatically different from those on Earth. The spaceflight environment has been known to influence human physiology and behavior on orbital missions. In this study, we investigated alterations in the diurnal rhythms of activity and heart rate of three Chinese astronauts on a space mission. An analysis of the heart rate data showed a significant decrease in heart rate amplitudes during flight in all three subjects. The heart rate amplitudes of all the three astronauts were significantly dampened during flight, and the minimum as well as the maximum value of heart rate increased after flight. A phase shift in heart rate was observed in one of the three astronauts after flight. These results demonstrate the influence of spaceflight on heart physiology and function. In addition, a significant decrease in body trunk activity and rhythmicity occurred during flight, demonstrating that the spaceflight environment disturbs motion adaptation and diurnal activity rhythms.

Altered Gravity Simulated by Parabolic Flight and Water Immersion Leads to Decreased Trunk Motion.

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.