Late circadian phase in adults and children is correlated with use of high color temperature light at home at night

Light is the strongest synchronizer of human circadian rhythms, and exposure to residential light at night reportedly causes a delay of circadian rhythms. The present study was conducted to investigate the association between color temperature of light at home and circadian phase of salivary melatonin in adults and children. Twenty healthy children (mean age: 9.7 year) and 17 of their parents (mean age: 41.9 years) participated in the experiment. Circadian phase assessments were made with dim light melatonin onset (DLMO). There were large individual variations in DLMO both in adults and children. The average DLMO in adults and in children were 21:50 ± 1:12 and 20:55 ± 0:44, respectively. The average illuminance and color temperature of light at eye level were 139.6 ± 82.7 lx and 3862.0 ± 965.6 K, respectively. There were significant correlations between color temperature of light and DLMO in adults (r = 0.735, p < 0.01) and children (r = 0.479, p < 0.05), although no significant correlations were found between illuminance level and DLMO. The results suggest that high color temperature light at home might be a cause of the delay of circadian phase in adults and children.     

Phylogeography of lethal male fighting in a social spider mite

When males fight for access to females, such conflict rarely escalates into lethal fight because the risks and costs involved, that is, severe injury or death, are too high. The social spider mite, Stigmaeopsis miscanthi, does exhibit lethal male fights, and this male–male aggressiveness varies among populations. To understand the evolution of lethal fighting, we investigated aggressiveness in 42 populations and phylogenetic relationships in 47 populations along the Japanese archipelago. By analysis of the male weapon morph, a proxy for aggressiveness, we confirmed the existence of a mildly aggressive (ML) form, besides the low aggression (LW) and high aggression (HG) forms reported earlier. To evaluate demographic history of these three forms, we employed the approximate Bayesian computation approach using mtCOI sequences and taking into consideration the postlast glacial expansion history of the host plant, Miscanthus sinensis. As results, hierarchical split models are more likely to explain the observed genetic pattern than admixture models, and the ML form in the subtropical region was considered the ancestral group. The inferred demographic history was consistent with the one reconstructed for the host plant in a previous study. The LW form was split from the ML form during the last glacial period (20,000–40,000 years BP), and subsequently, the HG form was split from the ML form at the end of or after the last glacial period (5,494–10,988 years BP). The results also suggest that the mite invaded Japan more than once, resulting in the present parapatric distribution of LW and HG forms in eastern Japan.     

Fmoc-based solid-phase synthesis of GPR54-agonistic pentapeptide derivatives containing alkene- and fluoroalkene-dipeptide isosteres

Fmoc-protected Phe-Gly-type (Z)-alkene dipeptide isostere (ADI) and (E)-fluoroalkene dipeptide isostere (FADI) were synthesized and applied to Fmoc-based solid-phase peptide synthesis (SPPS). These cis-peptide bond mimetics were introduced into a bioactive pentapeptide [H-Amb-Phe-Gly-Leu-Arg-Trp-NH(2); Amb = 4-(aminomethyl) benzoic acid], which has potent GPR54 agonistic activity. The resulting pentapeptide derivatives showed low GPR54 agonistic activity, as compared with the parent peptide and (E)-ADI-containing derivative. This suggests that the trans-amide conformer of Phe-Gly peptide bond of the parent peptide would be significantly important for bioactivity. Contrary to our expectations, a (Z)-FADI-containing derivative exhibited essentially no activity, revealing the necessity of critical validation of FADI-bioisosterism.     

Comparison of stress responses between mental tasks and white noise exposure

The purpose of this study was to compare the cardiovascular responses to different types of mental stress. Ten healthy males performed a mental arithmetic task (MA) on one day and were exposed to white noise (WN, 80dB) on another day. Both the MA and the WN were composed of four 5-min consecutive periods with a 3-min rest between them. On each day, the systolic and diastolic blood pressure (SBP and DBP), mean arterial pressure (MAP), cardiac output (CO), and total peripheral resistance (TPR) were measured continually during the entire experimental period. The changes from the baseline (Delta) in all periods were calculated for both mental stresses. As for the results, the DeltaMAP, DeltaCO, DeltaHR, and DeltaTPR in the MA did not significantly change during the task periods. However, in the WN, the DeltaMAP and DeltaTPR showed significant increases over the time of the consecutive periods. In addition, we discuss the response patterns for the two mental stresses. We examine three hemodynamic reactivity patterns: a cardiac pattern characterized by increased CO and decreased TPR, a mixed pattern characterized by a moderate increase in both CO and TPR, and a vascular pattern characterized by increased TPR and decreased CO. The results show that throughout all task/exposure periods, the response pattern remained the same for six subjects in each stress. Furthermore, of these six subjects, half showed the same response pattern in both the MA and the WN. In conclusion, compared to the MA task, consecutive WN exposure showed an accumulation of stress responses. A change in TPR contributed to a gradual increase in MAP in the WN. It is also possible that among the subjects there were different types of response to the MA and WN.     

Effects of object color stimuli on human brain activities in perception and attention referred to EEG alpha band response

This study was designed to investigate the physiological effects of color in terms of blood pressure and the results of electroencephalogram (EEG) as subjects looked at the sheets of paper of various colors. A questionnaire was also used to assess psychological effects. Three colors (red, green, blue) were shown to each subject in randomized order. The various colors showed distinctly different effects on the mean power of the alpha band, theta band, and on the total power in the theta-beta EEG bandwidth and alpha attenuation coefficient (AAC). Scores of the subjective evaluations concerning heavy, excited, and warm feelings also indicated significant differences between red and blue conditions. Against to our prediction, blue elicited stronger arousal than did red as expressed by the results of AAC and the mean power of the alpha band, which conflicted with the results of the subjective evaluations scores. This phenomenon might be caused by bluish light's biological activating effect. The powers of the alpha band, and the theta band, and the total power of the theta-beta bandwidth as measured by EEG showed larger values while the subjects looked at red paper than while they looked at blue paper. This indicated that red possibly elicited an anxiety state and therefore caused a higher level of brain activity in the areas of perception and attention than did the color blue. Red paper's effect to activate the central cortical region with regard to perception and attention was considerably more distinguishable than was the biological activating effect of bluish light in our study.     

Applicability of a segmental bioelectrical impedance analysis for predicting the whole body skeletal muscle volume.

This study aimed to test the hypothesis that a segmental bioelectrical impedance (BI) analysis can predict whole body skeletal muscle (SM) volume more accurately than a whole body BI analysis. Thirty males (19-34 yr) participated in this study. They were divided into validation (n = 20) and cross-validation groups (n = 10). The BI values were obtained using two methods: whole body BI analysis, which determines impedance between the wrist and ankle; and segmental BI analysis, which determines the impedance of every body segment in both sides of the upper arm, lower arm, upper leg and lower leg, and five parts of the trunk. Using a magnetic resonance imaging method, whole body SM volume was determined as a reference (SMV(MRI)). Simple and multiple regression analyses were applied to (length)(2)/Z (BI index) for the whole body and for every body segment, respectively, to develop the prediction equations of SMV(MRI). In the validation group, there were no significant differences between the measured and estimated SMV and no systematic errors in either BI analysis. In the cross-validation group, the whole body BI analysis produced systematic errors and resulted in the overestimation of SMV(MRI), but the segmental BI analysis was cross-validated. In the pooled data, the segmental BI analysis produced a prediction equation, which involves the BI indexes of the trunk and upper thigh as independent variables, with a SE of estimation of 1,693.8 cm(3) (6.1%). Thus the findings obtained here indicated that the segmental BI analysis is superior to the whole body BI analysis for estimating SMV(MRI).     

A simple quantitative chiral analysis of amino acid esters by fluorine‐19 nuclear magnetic resonance using the modified James–Bull method

A simple chiral analysis of amino acid esters by fluorine‐19 nuclear magnetic resonance (¹⁹F NMR) through the modified James–Bull method is described. Thus, amino acid ester acid salt was treated with 5‐fluoro‐2‐formylphenylboronic acid and (S)‐BINOL in the presence of triethylamine (TEA) and MS4A for 10 minutes. The reaction mixture was analysed by ¹⁹F NMR directly to afford good quantifications.     

Quantitation and sensory properties of three newly identified pyroglutamyl oligopeptides in sake

Three new peptides: (pGlu)L-ethyl, (pGlu)LFGP-ethyl and (pGlu)LFNP-ethyl, were identified in the search for pyroglutamyl oligopeptide ethyl esters in sake. The ethyl esterified peptides in sake were quantitated using stable isotope dilution analysis and additional quantitation of (pGlu)L was performed using an external standard method. The concentrations of (pGlu)L-ethyl and (pGlu)L in 33 commercial sake samples ranged from 0.16 to 1.57 mg/L and 1.49 to 7.55 mg/L, respectively. The sensory properties of the pyroglutamyl oligopeptide ethyl esters and corresponding non-esterified peptides were examined: the estimated difference threshold of (pGlu)L (2.0 mg/L) and (pGlu)L-ethyl (0.267 mg/L) was exceeded in 32 and 26 samples, respectively. Estimated thresholds of (pGlu)LFGP-ethyl and (pGlu)LFNP-ethyl were often lower than the levels in quantitated sake samples. The sensory effects of these pyroglutamyl dipeptides on a model sake quality may be negative because of their unpleasant taste, however, (pGlu)LFNP-ethyl may be positive because of its mild taste.     

Placental Mammals Acquired Functional Sequences in NRK for Regulating the CK2–PTEN–AKT Pathway and Placental Cell Proliferation

The molecular evolution processes underlying the acquisition of the placenta in eutherian ancestors are not fully understood. Mouse NCK-interacting kinase (NIK)-related kinase (NRK) is expressed highly in the placenta and plays a role in preventing placental hyperplasia. Here, we show the molecular evolution of NRK, which confers its function for inhibiting placental cell proliferation. Comparative genome analysis identified NRK orthologs across vertebrates, which share the kinase and citron homology (CNH) domains. Evolutionary analysis revealed that NRK underwent extensive amino acid substitutions in the ancestor of placental mammals and has been since conserved. Biochemical analysis of mouse NRK revealed that the CNH domain binds to phospholipids, and a region in NRK binds to and inhibits casein kinase-2 (CK2), which we named the CK2-inhibitory region (CIR). Cell culture experiments suggest the following: 1) Mouse NRK is localized at the plasma membrane via the CNH domain, where the CIR inhibits CK2. 2) This mitigates CK2-dependent phosphorylation and inhibition of PTEN and 3) leads to the inhibition of AKT signaling and cell proliferation. Nrk deficiency increased phosphorylation levels of PTEN and AKT in mouse placenta, supporting our hypothesis. Unlike mouse NRK, chicken NRK did not bind to phospholipids and CK2, decrease phosphorylation of AKT, or inhibit cell proliferation. Both the CNH domain and CIR have evolved under purifying selection in placental mammals. Taken together, our study suggests that placental mammals acquired the phospholipid-binding CNH domain and CIR in NRK for regulating the CK2–PTEN–AKT pathway and placental cell proliferation.