The Influence of Polyploidy and Genome Composition on Genomic Imprinting in Mice

Genomic imprinting is an epigenetic mechanism that switches the expression of imprinted genes involved in normal embryonic growth and development in a parent-of-origin-specific manner. Changes inDNAmethylation statuses from polyploidization are a well characterized epigenetic modification in plants. However, how changes in ploidy affect both imprinted gene expression and methylation status in mammals remains unclear. To address this, we used quantitative real time PCR to analyze expression levels of imprinted genes in mouse tetraploid fetuses. We used bisulfite sequencing to assess the methylation statuses of differentially methylated regions (DMRs) that regulate imprinted gene expression in triploid and tetraploid fetuses. The nine imprinted genes H19, Gtl2, Dlk1, Igf2r, Grb10, Zim1, Peg3, Ndn, and Ipw were all unregulated; in particular, the expression of Zim1 was more than 10-fold higher, and the expression of Ipw was repressed in tetraploid fetuses. The methylation statuses of four DMRs H19, intergenic (IG), Igf2r, and Snrpn in tetraploid and triploid fetuses were similar to those in diploid fetuses. We also performed allele-specific RT-PCR sequencing to determine the alleles expressing the three imprinted genes Igf2, Gtl2, and Dlk1 in tetraploid fetuses. These three imprinted genes showed monoallelic expression in a parent-of-origin-specific manner. Expression of non-imprinted genes regulating neural cell development significantly decreased in tetraploid fetuses, which might have been associated with unregulated imprinted gene expression. This study provides the first detailed analysis of genomic imprinting in tetraploid fetuses, suggesting that imprinted gene expression is disrupted, but DNA methylation statuses of DMRs are stable following changes in ploidy in mammals

Evolution of Synchrotron X-rays in Supernova Remnants

A systematic study of the synchrotron X-ray emission from supernova remnants (SNRs) has been conducted. We selected a total of 12 SNRs whose synchrotron X-ray spectral parameters are available in the literature with reasonable accuracy, and studied how their luminosities change as a function of radius. It is found that the synchrotron X-ray luminosity tends to drop especially when the SNRs become larger than ~5 pc, despite large scatter. This may be explained by the change of spectral shape caused by the decrease of the synchrotron roll-off energy. A simple evolutionary model of the X-ray luminosity is proposed and is found to reproduce the observed data approximately, with reasonable model parameters. According to the model, the total energy of accelerated electrons is estimated to be 10^(47-48) ergs, which is well below the supernova explosion energy. The maximum energies of accelerated electrons and protons are also discussed.Comment: 6 pages, 2 figures, ApJ, in pres

Poliovirus trafficking toward central nervous system via human poliovirus receptor-dependent and -independent pathway

In humans, paralytic poliomyelitis results from the invasion of the central nervous system (CNS) by circulating poliovirus (PV) via the blood–brain barrier (BBB). After the virus enters the CNS, it replicates in neurons, especially in motor neurons, inducing the cell death that causes paralytic poliomyelitis. Along with this route of dissemination, neural pathway has been reported in humans, monkeys, and PV-sensitive human PV receptor (hPVR/CD155)-transgenic (Tg) mice. We demonstrated that a fast retrograde axonal transport process is required for PV dissemination through the sciatic nerve of hPVR-Tg mice and that intramuscularly inoculated PV causes paralysis in a hPVR-dependent manner. We also showed that hPVR-independent axonal transport of PV exists in hPVR-Tg and non-Tg mice, indicating that several different pathways for PV axonal transport exist in these mice. Circulating PV after intravenous inoculation in mice cross the BBB at a high rate in a hPVR-independent manner. We will implicate an involvement of a new possible receptor for PV to permeate the BBB based on our recent findings

Trajectory analysis of Polar Patrol Balloon (PPB) flights in the stratosphere over Antarctica in summer and spring: A preliminary result

Actual trajectories of two PPB's which flew in the Antarctic stratosphere in austral summer and spring are compared with those calculated based on objective analysis data of Japan Meteorological Agency (JMA). The differences between the actual and calculated trajectories are discussed to check reliability of the JMA objective analysis data for the stratosphere, and to detect subsynoptic scale variability due to gravity waves and others

Evaluation of liver function for hepato-biliary-pancreatic surgery

In the present study, liver function at pre-operative and postoperative period was evaluated by various examinations. Patients with obstructive jaundice (n=14) and liver tumor (n=6) often have complications such as postoperative hepatic failure (n=4). They were divided into 3 groups: group A (n=7) had postoperative complications, group B (n=13) had uneventful postoperative course and group C (n=4) had postoperative hepatic failure. Liver function had significant correlations with levels of total bilirubin max (T-Bil max), hepaplastin tests (HPT) and ALPratio (post ope/pre-ope). Group C had T-Bil max≧30 mg/dl, HPT≦60% (54.4±14.7), ALPratio≧1.5, and admission ALP≧3000. We determined the level of bilirubin per day in drained blie (V-Bil) in 14 patients who underwent biliary drainage to ensure precise evalution of preoperative liver function. V-Bil was 332.9±140.0 mg/day on average, showing a close correlation with the serum bilirubin decreasing rate "b" and ICG R 15 (p<0.05). V-Bil is useful for evaluation of liver function in patients with malignant obstructive jaundice. In 6 patients without cirrhosis undergoing partial hepatectomy for liver tumor, ALPratio (≧1.5), a blood loss during operation (≧500), and operating time were related to the onset of postoperative hepatic failure