Spatio-Temporal Expression Profile of Stem Cell-Associated Gene LGR5 in the Intestine during Thyroid Hormone-Dependent Metamorphosis in Xenopus laevis

The intestinal epithelium undergoes constant self-renewal throughout adult life across vertebrates. This is accomplished through the proliferation and subsequent differentiation of the adult stem cells. This self-renewal system is established in the so-called postembryonic developmental period in mammals when endogenous thyroid hormone (T3) levels are high.The T3-dependent metamorphosis in anurans like Xenopus laevis resembles the mammalian postembryonic development and offers a unique opportunity to study how the adult stem cells are developed. The tadpole intestine is predominantly a monolayer of larval epithelial cells. During metamorphosis, the larval epithelial cells undergo apoptosis and, concurrently, adult epithelial stem/progenitor cells develop de novo, rapidly proliferate, and then differentiate to establish a trough-crest axis of the epithelial fold, resembling the crypt-villus axis in the adult mammalian intestine. The leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5) is a well-established stem cell marker in the adult mouse intestinal crypt. Here we have cloned and analyzed the spatiotemporal expression profile of LGR5 gene during frog metamorphosis. We show that the two duplicated LGR5 genes in Xenopus laevis and the LGR5 gene in Xenopus tropicalis are highly homologous to the LGR5 in other vertebrates. The expression of LGR5 is induced in the limb, tail, and intestine by T3 during metamorphosis. More importantly, LGR5 mRNA is localized to the developing adult epithelial stem cells of the intestine.These results suggest that LGR5-expressing cells are the stem/progenitor cells of the adult intestine and that LGR5 plays a role in the development and/or maintenance of the adult intestinal stem cells during postembryonic development in vertebrates

Reactive orbital energy theory serving a theoretical foundation for the electronic theory of organic chemistry

It is established that the reactive orbital energy theory (ROET) theoretically reproduces the rule-based electronic theory diagrams of organic chemistry by a comparative study on the charge transfer natures of typical organic carbon-carbon and carbon-heteroatom bond formation reactions: aldol, Mannich, alpha-aminooxylation, and isogyric reactions. The ROET, which is an expansion of the reaction electronic theories (e.g., the frontier orbital theory) in terms of orbital energies, elucidates the reactive orbitals driving reactions and the charge transferability indices of the reactions. Performing the ROET analyses of these reactions shows that the charge transfer directions given in the rule-based diagrams of the electronic theory are reproduced even for the functional groups of charge transfer destinations in all but only two processes for 38 reaction processes. The ROET analyses also make clear the detailed orbital-based pictures of these bond formation reactions: that is, the use of the out-of-plane antibonding pi orbitals in acidic conditions (enol-mode) and in-plane antibonding pi orbitals in basic conditions (enolate-mode), which explain the experimentally assumed mechanisms such as the pi-bond formations in acidic conditions and sigma-bond formations at alpha-carbons in basic conditions. Furthermore, the ROET analyses explicate that the methyl group initially accepts electrons and then donates them to the bond formations in the target reactions. It is, consequently, suggested that the ROET serves a theoretical foundation for the electronic theory of organic chemistry

Autophagy inhibits viral genome replication and gene expression stages in West Nile virus infection

Autophagy is a lysosomal degradation pathway that is implicated in many viral infections. However, its role in West Nile virus (WNV) infection remains controversial. In the present study, we examined the relationship between WNV infection and autophagy in infected cells. We demonstrated that LC3-II expression, a molecular marker for autophagosomal membranes, was enhanced in WNV-infected cells 6 h post-infection. LC3-II expression was further enhanced in WNV-inoculated cells when treated with a lysosomal protease inhibitor. Meanwhile, WNV replication in cells lacking Atg5, an essential factor for autophagy, was increased compared with replication in wild-type cells. In addition, WNV replication was inhibited in cells lacking Atg5 when they were transfected with an ATG5 expression plasmid. These results suggest an antiviral role for autophagy in WNV-infected cells. We also examined which viral replication stages were affected by autophagy by using a Tat-beclin 1 peptide to induce autophagy and pseudo-infectious WNV reporter virus particles (WNV-RVPs) that monitor viral genome replication and gene expression stages via GFP expression. We found that autophagy induction in HeLa cells by Tat-beclin 1 peptide 3 h after WNV inoculation inhibited viral replication, and GFP expression was significantly inhibited in wild-type cells when compared with cells lacking Atg5. Taken together, these results suggest that autophagy is induced by WNV infection, and that this induction inhibits WNV replication at the viral genome replication and gene expression stages. (C) 2014 Elsevier B.V. All rights reserved

Development and Improvement Status of Active X-Ray Generators for Future Lunar and Planetary Landing Observations

The performance of pyroelectric X-ray generator (PXG) under high vacuum (down to 2.2 × 10-5 Pa) is investigated with two different gases of dry air and N2, in order to develop a high-intensity X-ray generator. For both gases, the X-ray intensity decreases for pressures less than 1 × 10-4 Pa. It is required to control appropriate inner-gas pressure (1 - 10-3 Pa) to obtain high X-ray intensity, when PXG is used as an active X-ray source for future planetary exploration missions. Furthermore, an analytical system with a carbon nanotube X-ray generator is also discussed for light-element measurement

Method for releasing carbon foils from substrates

The performance of a carbon foil (C-foil) as a charge stripper in an accelerator is directly affected by its condition and quality. C-foils are fabricated by evaporating carbon onto a substrate. Therefore, a suitable technique must be established for depositing and removing C-foils from substrates. The selection of appropriate releasing agents is crucial for the removal process. C-foils with thicknesses less than 0.1 mg/cm2 were produced using the arc discharge method, wherein chloride materials were used as releasing agents. The magnetron sputtering method is suitable for manufacturing C-foils thicker than 0.1 mg/cm2 using appropriate releasing agents, such as fluorine-based or silicon-based agents. The contact angle analysis demonstrates a negative relationship between the C-foil thickness and the wettability of the substrate treated with an appropriate releasing agent. The possibility of using ionic liquids as novel releasing agents is also investigated

Effects of subjective effort on overground and treadmill running: a comparative analysis

In this study, we investigated the differences in performance and kinematics between overground and treadmill running using the same amount of subjective effort. Fourteen female participants performed a 50-m sprint, running at maximum effort (100% subjective effort) as the maximal task on the ground. Subsequently, based on 100% subjective effort, they performed the grading task on the ground and on the treadmill at 30, 50, and 70% subjective effort. The running motion was recorded using a high-speed camera. We observed a significant difference in running velocity between the overground and treadmill conditions because treadmill running was recognized as having a greater load than overground running. The running velocity could be adjusted according to the subjective effort required for both overground and treadmill running. On the treadmill, running velocity was adjusted by maintaining flight time with increased subjective effort. Additionally, running velocity was adjusted by both step frequency and step length on the treadmill, whereas overground running velocity was adjusted by step frequency rather than step length. We also observed that overground, the knee angle was more flexible with an increase in subjective effort through one gait cycle, and the ankle joint was fixed at a high subjective effort. On the treadmill, the knee angle was adjusted only during the swing phase, and greater dorsiflexion was observed at high subjective effort