RNA sequencing reveals small RNAs differentially expressed between incipient Japanese threespine sticklebacks

BACKGROUND: Non-coding small RNAs, ranging from 20 to 30 nucleotides in length, mediate the regulation of gene expression and play important roles in many biological processes. One class of small RNAs, microRNAs (miRNAs), are highly conserved across taxa and mediate the regulation of the chromatin state and the post-transcriptional regulation of messenger RNA (mRNA). Another class of small RNAs is the Piwi-interacting RNAs, which play important roles in the silencing of transposons and other functional genes. Although the biological functions of the different small RNAs have been elucidated in several laboratory animals, little is known regarding naturally occurring variation in small RNA transcriptomes among closely related species. RESULTS: We employed next-generation sequencing technology to compare the expression profiles of brain small RNAs between sympatric species of the Japanese threespine stickleback (Gasterosteus aculeatus). We identified several small RNAs that were differentially expressed between sympatric Pacific Ocean and Japan Sea sticklebacks. Potential targets of several small RNAs were identified as repetitive sequences. Female-biased miRNA expression from the old X chromosome was also observed, and it was attributed to the degeneration of the Y chromosome. CONCLUSIONS: Our results suggest that expression patterns of small RNA can differ between incipient species and may be a potential mechanism underlying differential mRNA expression and transposon activity

Effect of medical institution change on gestational duration after the Great East Japan Earthquake: The Fukushima Health Management Survey

Aim: The aim of this study was to examine the association between medical institution change for perinatal care and gestational duration after the Great East Japan Earthquake using data from the Fukushima Health Management Survey. Methods: The data of pregnant women who experienced the earthquake in Fukushima prefecture and participated in the Pregnancy and Birth Survey as part of the Fukushima Health Management Survey were analyzed. The primary and secondary outcomes of this study were gestational duration and preterm birth, respectively. The main study factor was prenatal checkup institution (only one institution, changed institution due to self-referral, changed institution due to medical indication, and went to parents' home for childbirth). Self-referral was considered as indicative of relocation after the disaster. Multiple linear and logistic regression analyses were conducted to examine the effect of earthquake on each outcome. Results: A total of 5593 (60.2%) participants experienced the earthquake between the 4th and 37th weeks of their gestational period. After controlling for variables, pregnant women who changed their perinatal checkup institution due to medical indication were significantly associated with shorter gestational duration (β = -10.6, P < 0.001) and preterm birth (adjusted odds ratio, 8.5; 95% confidence interval, 5.8-12.5) compared with women who visited only one institution. Self-referral, however, was not significantly associated with the outcomes. Conclusion: According to prenatal checkup status, our results suggest that the effect on gestational duration of the Great East Japan Earthquake and the subsequent Fukushima Daiichi nuclear disaster was not significant

The Role of Stochastic Acceleration in the Prompt Emission of Gamma-Ray Bursts: Application to Hadronic Injection

We study effects of particle re-acceleration (or heating) in the post-shock region via magnetohydrodynamic/plasma turbulence, in the context of a mixed hadronic-leptonic model for the prompt emission of gamma-ray bursts (GRBs), using both analytical and numerical methods. We show that stochastically accelerated (or heated) leptons, which are injected via pp and pg reactions and subsequent pair cascades, are plausibly able to reproduce the Band function spectra with alpha~1 and beta~2-3 in the ~MeV range. An additional hard component coming from the proton-induced cascade emission is simultaneously expected, which is compatible with observed extra power-law spectra far above the MeV range. We also discuss the specific implications of hadronic models for ongoing high-energy neutrino observations.Comment: 12 pages, 8 figures, accepted for publication in ApJ, discussions added, typos fixed. Results unchange

Developmental Trajectories of Body Mass Index Among Japanese Children and Impact of Maternal Factors during Pregnancy

Background The aims of this study were to 1) determine the distinct patterns of body mass index (BMI) trajectories in Japanese children, and 2) elucidate the maternal factors during pregnancy, which contribute to the determination of those patterns. Methodology/Principal Findings All of the children (1,644 individuals) born in Koshu City, Japan, between 1991 and 1998 were followed in a longitudinal study exploring the subjects’ BMI. The BMI was calculated 11 times for each child between birth and 12 years of age. Exploratory latent class growth analyses were conducted to identify trajectory patterns of the BMI z-scores. The distribution of BMI trajectories were best characterized by a five-group model for boys and a six-group model for girls. The groups were named “stable thin,” “stable average,” “stable high average,” “progressive overweight,” and “progressive obesity” in both sexes; girls were allocated to an additional group called “progressive average.” Multinomial logistic regression found that maternal weight, smoking, and skipping breakfast during pregnancy were associated with children included in the progressive obesity pattern rather than the stable average pattern. These associations were stronger for boys than for girls. Conclusions/Significance Multiple developmental patterns in Japanese boys and girls were identified, some of which have not been identified in Western countries. Maternal BMI and some unfavorable behaviors during early pregnancy may impact a child’s pattern of body mass development. Further studies to explain the gender and regional differences that were identified are warranted, as these may be important for early life prevention of weight-associated health problems