Retrotransposons Manipulating Mammalian Skeletal Development in Chondrocytes

Retrotransposons are genetic elements that copy and paste themselves in the host genome through transcription, reverse-transcription, and integration processes. Along with their proliferation in the genome, retrotransposons inevitably modify host genes around the integration sites, and occasionally create novel genes. Even now, a number of retrotransposons are still actively editing our genomes. As such, their profound role in the evolution of mammalian genomes is obvious; thus, their contribution to mammalian skeletal evolution and development is also unquestionable. In mammals, most of the skeletal parts are formed and grown through a process entitled endochondral ossification, in which chondrocytes play central roles. In this review, current knowledge on the evolutional, physiological, and pathological roles of retrotransposons in mammalian chondrocyte differentiation and cartilage development is summarized. The possible biological impact of these mobile genetic elements in the future is also discussed

Non-destructive on-chip cell sorting system with real-time microscopic image processing

Studying cell functions for cellomics studies often requires the use of purified individual cells from mixtures of various kinds of cells. We have developed a new non-destructive on-chip cell sorting system for single cell based cultivation, by exploiting the advantage of microfluidics and electrostatic force. The system consists of the following two parts: a cell sorting chip made of poly-dimethylsiloxane (PDMS) on a 0.2-mm-thick glass slide, and an image analysis system with a phase-contrast/fluorescence microscope. The unique features of our system include (i) identification of a target from sample cells is achieved by comparison of the 0.2-μm-resolution phase-contrast and fluorescence images of cells in the microchannel every 1/30 s; (ii) non-destructive sorting of target cells in a laminar flow by application of electrostatic repulsion force for removing unrequited cells from the one laminar flow to the other; (iii) the use of agar gel for electrodes in order to minimize the effect on cells by electrochemical reactions of electrodes, and (iv) pre-filter, which was fabricated within the channel for removal of dust contained in a sample solution from tissue extracts. The sorting chip is capable of continuous operation and we have purified more than ten thousand cells for cultivation without damaging them. Our design has proved to be very efficient and suitable for the routine use in cell purification experiments

Pro- and Antiapoptotic Markers in Upper Tract Urothelial Carcinoma Associated with Balkan Endemic Nephropathy

The role of aristolochic acid in the etiology of Balkan endemic nephropathy (BEN) and associated upper-tract urothelial carcinoma (UTUC) has been recently confirmed. The aim of this study was to determine apoptosis-related marker(s) specific for BEN-associated UTUC. Present investigation included 105 patients with UTUC, 44 from BEN region and 61 control tumors. Altered expression of Survivin was more often present in BEN UTUC with high grade and solid growth (P < 0.005; P < 0.05) than in control tumors. Significantly lower expression of proapoptotic marker Bax was found in BEN tumors with high grade, high stage, necrosis, and without metaplastic change (P < 0.05; 0.05; 0.05; 0.05) compared to control tumors with the same features. Group (BEN-related/control), stage, growth pattern, and caspase 3 activity were significantly associated with the expression of Bax (P = 0.002, 0.034, 0.047, 0.028, resp.,). This investigation identifies Bax as specific marker of BEN-associated UTUC. Decrease of pro-apoptotic protein Bax together with alteration of Survivin may be indicative for specific disturbances of intrinsic apoptotic pathway in UTUC arising in endemic areas

X-ray and Neutron Study on the Structure of Hydrous SiO2 Glass up to 10 GPa

The structure of hydrous amorphous SiO2 is fundamental in order to investigate the effects of water on the physicochemical properties of oxide glasses and magma. The hydrous SiO2 glass with 13 wt.% D2O was synthesized under high-pressure and high-temperature conditions and its structure was investigated by small angle X-ray scattering, X-ray diffraction, and neutron diffraction experiments at pressures of up to 10 GPa and room temperature. This hydrous glass is separated into two phases: a major phase rich in SiO2 and a minor phase rich in D2O molecules distributed as small domains with dimensions of less than 100 angstrom. Medium-range order of the hydrous glass shrinks compared to the anhydrous SiO2 glass by disruption of SiO4 linkage due to the formation of Si-OD deuterioxyl, while the response of its structure to pressure is almost the same as that of the anhydrous SiO2 glass. Most of D2O molecules are in the small domains and hardly penetrate into the void space in the ring consisting of SiO4 tetrahedra

Sulphur geodynamic cycle

Evaluation of volcanic and hydrothermal fluxes to the surface environments is important to elucidate the geochemical cycle of sulphur and the evolution of ocean chemistry. This paper presents S/3He ratios of vesicles in mid-ocean ridge (MOR) basalt glass together with the ratios of high-temperature hydrothermal fluids to calculate the sulphur flux of 100 Gmol/y at MOR. The S/3He ratios of high-temperature volcanic gases show sulphur flux of 720 Gmol/y at arc volcanoes (ARC) with a contribution from the mantle of 2.9%, which is calculated as 21 Gmol/y. The C/S flux ratio of 12 from the mantle at MOR and ARC is comparable to the C/S ratio in the surface inventory, which suggests that these elements in the surface environments originated from the upper mantle.UTokyo Research掲載「硫黄が大気、海洋、マントルを巡る様子」 URI: http://www.u-tokyo.ac.jp/ja/utokyo-research/research-news/deep-sulfur-cycle-involving-atmosphere-ocean-and-mantle.htmlUTokyo Research "Deep sulfur cycle involving atmosphere, ocean and mantle" URI: http://www.u-tokyo.ac.jp/en/utokyo-research/research-news/deep-sulfur-cycle-involving-atmosphere-ocean-and-mantle.htm