Methionine Metabolism Regulates Maintenance and Differentiation of Human Pluripotent Stem Cells

SummaryMouse embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) are in a high-flux metabolic state, with a high dependence on threonine catabolism. However, little is known regarding amino acid metabolism in human ESCs/iPSCs. We show that human ESCs/iPSCs require high amounts of methionine (Met) and express high levels of enzymes involved in Met metabolism. Met deprivation results in a rapid decrease in intracellular S-adenosylmethionine (SAM), triggering the activation of p53-p38 signaling, reducing NANOG expression, and poising human iPSC/ESCs for differentiation, follow by potentiated differentiation into all three germ layers. However, when exposed to prolonged Met deprivation, the cells undergo apoptosis. We also show that human ESCs/iPSCs have regulatory systems to maintain constant intracellular Met and SAM levels. Our findings show that SAM is a key regulator for maintaining undifferentiated pluripotent stem cells and regulating their differentiation

<ORIGINAL REPORT>X-ray scanning analytical microscopic and scanning electron microscopic studies of an unusual case of dens invaginatus

A mass was extirpated from the region of the maxillary right third molar of a 20 year-old patient. It was proved to be an extreme and unerupted case of dens invaginatus. The clinical and histopathological features have been presented in a previous paper. Ameloblasts and odontoblasts were noted along the surface of enamel or dentin. In the present study, X-ray scanning analytical microscopy (XSAM), a newly developed technique, together with scanning electron microscopy (SEM) was applied for the study of this malformed tooth. SEM study showed a strange arrangement of well-formed enamel and dentin in normal structures. The distribution of calcium (Ca) and phosphorus (P) was clearly observed by the XSAM method. It revealed that the bulk of dentin was composed of two kinds of dentin quite different in mineral content while their SEM appearances were similar. The part of the dentin near the dentinoenamel junction had much higher Ca and P concentrations than the outer parts. In conclusion, the disagreement between the microscopic findings and the XSAM findings suggests the importance of applying various methods in studies to obtain a comprehensive understanding of such malformation. In addition, the present investigation also points out the complexity of the disturbance ranging within the term dens invaginatus

production of chitooligosaccharides from Rhizopus oligosporus NRRL2710 cells by chitosanase digestion

The intact cells of Rhizopus oligosporus NRRL2710, whose cell walls are abundant source of N-acetylglu- cosamine (GlcNAc) and glucosamine (GlcN), were digested with three chitinolytic enzymes, a GH-46 chitosanase from Streptomyces sp. N174 (CsnN174), a chitinase from Pyrococcus furiosus, and a chitinase from Trichoderma viride, respectively. Solubilization of the intact cells by CsnN174 was found to be the most efficient from solid state CP/MAS 13C NMR spectroscopy. Chitosanase products from Rhizopus cells were purified by cation exchange chromatography on CM-Sephadex C-25 and gel-filtration on Cellulofine Gcl-25 m. NMR and MALDI-TOF-MS analyses of the purified products revealed that GlcN–GlcNAc, (GlcN)2–GlcNAc, and (GlcN)2 were produced by the enzymatic digestion of the intact cells. The chitosan- ase digestion of Rhizopus cells was found to be an excellent system for the conversion of fungal biomass without any environmental impact

Pharmacokinetic Drug Interaction Between Rosuvastatin and Tanjin in Healthy Volunteers and Rats

[Background] Tanjin is an herbal medicine made from the root of salvia miltiorrhiza. It is predominantly given to arteriosclerotic patients as a supplement to ameliorate the clinical symptoms of cardiovascular diseases. In China, tanjin is used frequently in combination treatment for hypercholesterolemia. Thus, there is a high probability of combination of tanjin and statins in these arteriosclerotic patients. This study investigated the interaction between tanjin and rosuvastatin. [Methods] We performed a randomized single-blind, two-period crossover clinical trial on six healthy male volunteers. Volunteers were administered rosuvastatin with placebo or a tanjin-containing drug randomly. The blood samples were collected before drug administration, and at 0.5, 1, 1.5, 2, 4, 8, and 12 hours after administration. Lymphocytes were isolated from blood samples before and 12 hours after drug administration to measure mRNA. As an animal experiment, an in situ intestinal injection with portal vein sampling model was used to examine the interaction between tanjin and rosuvastatin during the absorption phase. Rosuvastatin or rosuvastatin combined with tanjin solution was injected into the intestine. After injection, blood from the portal vein was collected and the concentration of rosuvastatin was measured by LC/MS/MS analysis. A portion of the intestine and liver from the rats was collected and stored at -80°C for mRNA measurement. [Results] In the clinical trial, co-administration of tanjin decreased the maximum plasma concentration (Cmax) of rosuvastatin by 26.85% compared with rosuvastatin alone, and also decreased the area under the plasma concentration-time curve of rosuvastatin from 0 to 12 h (AUC0?12) by 19.43%. The relative expression of BCRP and OATP mRNA in human lymphocytes was increased by co-administration of tanjin. In the animal experiment, co-administration of tanjin extract reduced the concentration of rosuvastatin to 84.4, 64.4, and 50.0% at 15, 30, and 45 minutes, respectively. The tanjin-containing drug had a similar effect to tanjin extract. Furthermore, tanjin significantly reduced the absorption of rosuvastatin and the inhibitory effects lasted for at least 24 hours. Tanjin increased the relative expression of BCRP mRNA in the intestine, but it did not change the expression of OATP. Moreover, the concentration of rosuvastatin in the portal vein and systemic blood was reduced. In the liver, tanjin increased both BCRP and OATP mRNA expression, which was consistent with the results from human lymphocytes. [Conclusion] The clinical trial and animal experiment revealed that tanjin can significantly reduce the absorption of rosuvastatin. This interaction occurred, at least, at the absorption phase in the small intestine due to the enhanced efflux transport. Thus, as tanjin and rosuvastatin were found to interact, their combination needs to be paid attention to

Simulation of SIMS for monomer and dimer of lignin under the assumption of thermal decomposition using QMD method,

金沢大学理工研究域物質化学系The thermal decomposition of the monomer and dimer of lignin has been simulated by a quantum molecular dynamics (DMD) method. In the calculation, we controlled the total energy of the system using Nóse-Hoover thermostats in the total energy range of 0.69-0.95 eV, and the sampling position data with a time step of 0.5 fs were carried out up to 3000 (1.5 ps) or 5000 (2.5 ps) steps in ab initio and semiempirical MO methods, respectively. We obtained the thermally decomposed fragments with positive, neutral and negative charges from SCF MO calculation at each data of the last MD step, and simulated the fragment distribution of the monomer and dimer lignins from the last step in 30-40 runs. Simulated mass numbers of positively and negatively charged fragments for lignin monomer and dimer showed considerably good accordance with the experimental results in TOF-SIMS observed by Saito and co-workers. © 2008 Elsevier B.V. All rights reserved

Heterochrony and developmental modularity of cranial osteogenesis in lipotyphlan mammals

Background Here we provide the most comprehensive study to date on the cranial ossification sequence in Lipotyphla, the group which includes shrews, moles and hedgehogs. This unique group, which encapsulates diverse ecological modes, such as terrestrial, subterranean, and aquatic lifestyles, is used to examine the evolutionary lability of cranial osteogenesis and to investigate the modularity of development. Results An acceleration of developmental timing of the vomeronasal complex has occurred in the common ancestor of moles. However, ossification of the nasal bone has shifted late in the more terrestrial shrew mole. Among the lipotyphlans, sequence heterochrony shows no significant association with modules derived from developmental origins (that is, neural crest cells vs. mesoderm derived parts) or with those derived from ossification modes (that is, dermal vs. endochondral ossification). Conclusions The drastic acceleration of vomeronasal development in moles is most likely coupled with the increased importance of the rostrum for digging and its use as a specialized tactile surface, both fossorial adaptations. The late development of the nasal in shrew moles, a condition also displayed by hedgehogs and shrews, is suggested to be the result of an ecological reversal to terrestrial lifestyle and reduced functional importance of the rostrum. As an overall pattern in lipotyphlans, our results reject the hypothesis that ossification sequence heterochrony occurs in modular fashion when considering the developmental patterns of the skull. We suggest that shifts in the cranial ossification sequence are not evolutionarily constrained by developmental origins or mode of ossification

Reconsideration of Laparoscopic Cholecystectomy

We describe the surgical method of cases showing a distended gallbladder. Because the most important thing does not cause biliary tract injury, it is to find orientation carefully. The frequency of incidental gallbladder cancer was in 7 (0.7%) of the 983. Only cholecystectomy is necessary to be performed for Tis or T1 cancer, and surgery has to be changed to radical surgery for T2 cancer or deeper invasion. Laparoscopic cholecystectomy is already an established standard operation. In the presence of acute or severe chronic inflammation, special attention should be paid to these points

Valence XPS, IR, and C13 NMR spectral analysis of 6 polymers by quantum chemical calculations

Valence XPS (VXPS), IR, and C13 NMR spectra of 6 polymers (PE, PS, PMMA, PET, Nylon6, PVC) have been analyzed using the model oligomers from B3LYP/6-31+G(d,p) basis calculations in GAUSSIAN 09. We simulated VXPS of the polymers by the negative of the orbital energies of the ground electronic state at the geometry-optimization of the model oligomers. The simulated VXPS spectra by B3LYP/6-31+G(d,p) basis level were compared with simulated spectra by calculations of SAOP method of ADF program. Simulated IR, and C13 NMR spectra of polymers were obtained from the other SCF calculations of B3LYP/6-31+G(d,p) basis using atomic coordinates of the model molecules at the geometry optimization, in order to gain the vibrational frequencies and nuclear magnetic shielding tensors, respectively. We have clarified the electronic states of the polymers from the good accordance of simulated VXPS, IR, and C13 NMR spectra of polymer models molecules with the experimental ones of the polymers. © 2012 Elsevier B.V.

教育実習を充実させるための取り組み報告 : 教育実習指導Bの改善 <第2部 教科研究>

広島大学附属福山中• 高等学校において実施されている教育実習をより充実させるために，社会科として，大学と連携をとりながら様々な取り組みをおこなってきた。本稿では，教育実習指導I・II (現場における教壇実習）の準備として行われる教育実習指導Bについて，広島大学において教育実習に関して何が求められているか，そして教育実習生がどのような現状にあるかをふまえ，社会科がどのような取り組みを行っているかを報告する