Photoperiodic diapause under the control of circadian clock genes in an insect

<p>Abstract</p> <p>Background</p> <p>Most organisms have evolved a circadian clock in order to anticipate daily environmental changes and many of these organisms are also capable of sophisticated measurement of daylength (photoperiodism) that is used to regulate seasonal events such as diapause, migration and polymorphism. It has been generally accepted that the same elements are involved in both circadian (daily) and seasonal (annual) rhythms because both rely upon daily light-dark cycles. However, as reasonable as this sounds, there remains no conclusive evidence of such a molecular machinery in insects. We have approached this issue by using RNA interference (RNAi) in <it>Riptortus pedestris</it>.</p> <p>Results</p> <p>The cuticle deposition rhythm exhibited the major properties of circadian rhythms, indicating that the rhythm is regulated by a circadian clock. RNAi directed against the circadian clock genes of <it>period </it>and <it>cycle</it>, which are negative and positive regulators in the circadian clock, respectively, disrupted the cuticle deposition rhythm and distinct cuticle layers were produced by these RNAi. Simultaneously, <it>period </it>RNAi caused the insect to avert diapause under a diapause-inducing photoperiod whereas <it>cycle </it>RNAi induced diapause under a diapause-averting photoperiod. The expression patterns of juvenile hormone-regulated genes and the application of juvenile hormone analogue suggested that neither ovarian development itself nor a downstream cascade of juvenile hormone secretion, were disturbed by <it>period </it>and <it>cycle </it>RNAi.</p> <p>Conclusions</p> <p>This study revealed that the circadian clock genes are crucial not only for daily rhythms but also for photoperiodic diapause. RNAi directed against <it>period </it>and <it>cycle </it>had opposite effects not only in the circadian cuticle deposition rhythm but also in the photoperiodic diapause. These RNAi also had opposite effects on juvenile hormone-regulated gene expression. It is still possible that the circadian clock genes pleiotropically affect ovarian development but, based on these results, we suggest that the circadian clock operated by the circadian clock genes, <it>period </it>and <it>cycle</it>, governs seasonal timing as well as the daily rhythms.</p> <p>See Commentary: <url>http://www.biomedcentral.com/1741-7007/8/115</url></p

Common features in diverse insect clocks

This review describes common features among diverse biological clocks in insects, including circadian, circatidal, circalunar/circasemilunar, and circannual clocks. These clocks control various behaviors, physiological functions, and developmental events, enabling adaptation to periodic environmental changes. Circadian clocks also function in time-compensation for celestial navigation and in the measurement of day or night length for photoperiodism. Phase response curves for such clocks reported thus far exhibit close similarities; specifically, the circannual clock in Anthrenus verbasci shows striking similarity to circadian clocks in its phase response. It is suggested that diverse biological clocks share physiological properties in their phase responses irrespective of period length. Molecular and physiological mechanisms are best understood for the optic-lobe and mid-brain circadian clocks, although there is no direct evidence that these clocks are involved in rhythmic phenomena other than circadian rhythms in daily events. Circadian clocks have also been localized in peripheral tissues, and research on their role in various rhythmic phenomena has been started. Although clock genes have been identified as controllers of circadian rhythms in daily events, some of these genes have also been shown to be involved in photoperiodism and possibly in time-compensated celestial navigation. In contrast, there is no experimental evidence indicating that any known clock gene is involved in biological clocks other than circadian clocks

Clinical Significance of the Neutrophil-to-Lymphocyte Ratio in IgA Vasculitis

Background: Some patients with immunoglobulin A (IgA) vasculitis develop severe disease, with severe abdominal symptoms that necessitate prolonged fasting. Moreover, no biomarkers that can predict severe disease have been clearly established. Methods: We analyzed the data of 65 children with IgA vasculitis who were admitted to our department between 2010 and 2015. Seven patients with severe abdominal symptoms who required fasting for at least one week were classified into the fasting group, and the remaining 58 patients were classified into the non-fasting group. The clinicopathological factors were compared between the two groups. Results: Significant differences in peripheral blood neutrophil-to-lymphocyte ratio (NLR), plasma D-dimer levels, and coagulation factor XIII activity at admission were observed between the two groups. Logistic regression analysis revealed that the NLR showed the highest odds ratio for severe abdominal symptoms (odds ratio, OR: 1.67; 95% confidence interval, CI: 1.14-2.45). The results of receiver operating characteristic (ROC) curve analysis revealed an area under the curve (AUC) of 0.89 for the NLR, and an optimum cutoff value of 2.8 was associated with a sensitivity of 100% and specificity of 72.5%. Conclusion: The NLR at diagnosis is a useful marker for predicting the severity of abdominal symptoms in patients with IgA vasculitis

A randomized controlled trial of a Functioning Improvement Tool home-visit program and its effect on cognitive function in older persons

Objective: The aim was to determine whether mini mental state examination (MMSE) scores improved in older participants of a Functioning Improvement Tool (FIT) home-visit program. Methods: Two hundred fifty-two participants aged 65 years or older living at home and receiving preventive services or a community long-term care prevention project according to the Japanese social long-term care insurance system were enrolled and randomly assigned to an intervention group (n = 128) or a control group (n = 124). Intervention group subjects received a 60-min FIT home-visit program for 3 months, which included guidance, assistance, and help in writing and teaching calculation in order to complete the FIT. Control subjects did not receive any home visits. Cognitive function was evaluated by MMSE. Analysis of covariance was used to examine the effects of the FIT adjusting for baseline MMSE scores, age, and sex. Results: Fifty-three subjects were excluded because of withdrawal, hospitalization, death, relocation, or missing data of MMSE; 199 subjects (60 men, 139 women; age 78.6 ± 7.4 years) were analyzed. The baseline MMSE scores did not differ between the intervention and control groups (24.2 ± 4.3 vs. 24.1 ± 4.7, p = 0.90). After the study period, the change in the MMSE score was significantly better in the intervention group than in the control group (0.8 ± 0.3 vs. −0.1 ± 0.2, p = 0.04). Stratified analyses showed that the intervention strategy was most effective in subjects with mild cognitive decline, with baseline MMSE scores from 18 to 23 points (1.9 ± 0.5 vs. −0.1 ± 2.8, p = 0.04). Conclusions: Our FIT home-visit program improved MMSE scores in older participants with mild cognitive decline