We have experimentally confirmed that the solubility of SiO2 in clinopyroxene at ultrahigh-pressure metamorphic conditions is buffered by coesite and kyanite. The present findings were derived from ...high-pressure experiments on metapelite glass, powdered andesite and eclogite glass under anhydrous conditions. The metapelite glass and powdered andesite were recrystallised in boron nitride capsules at 8GPa and 1100–1500°C. The eclogite glass was heated in an AuPd capsule, both ends of which were welded, at 3GPa and 1000°C.
Clinopyroxene nucleated from metapelite glass, the bulk composition of which is saturated in both SiO2 and Al2SiO5 components plotting within the Jd (Na,K)(Al,Cr)(Si,Ti)2O6−Qtz(Si,Ti)O2−GrtM3(Al,Cr)2(Si,Ti)3O12−Als(Al,Cr)2(Si,Ti)O5 tetrahedron (M=Fe,Mn,Mg,Ni,Zn,Ca), coexists with garnet, coesite and kyanite. The average excess silica content of the clinopyroxene ranges from 23.4 to 35.4mol%. In contrast, an andesite experiment saturated in SiO2 but undersaturated in Al2SiO5 within the Jd–Qtz–Aug M(Si,Ti)O3–Grt tetrahedron produced clinopyroxene, garnet and coesite but no kyanite. The average excess silica in the clinopyroxene was 9.7–15.5mol%, which is comparable to previous experimental data. Experiment on the eclogite glass with similar composition to andesite yielded clinopyroxene, garnet and coesite. An average excess silica content in clinopyroxene counts 6.4mol%, which is much lower than that obtained from the andesite.
The SiO2 content of clinopyroxene coexisting with garnet, coesite and kyanite is much higher than that of clinopyroxene coexisting with garnet and coesite without kyanite. Although the temperature dependence is unclear, the SiO2 solubility increases with pressure and Fe/(Fe+Mg). Clinopyroxene forms the solid solution series Jd–Es □0.5M0.5Al(Si,Ti)2O6 and Aug–Es, rather than Jd–Ts MAl2(Si,Ti)O6 and Es–Ts joins. Our experimental data suggest the probable existence of octahedral Si which may accompany the M2 vacancies in clinopyroxene.
•The excess SiO2 content of Cpx coexisting with Grt, Coe and Ky is much higher than that of Cpx in the Ky-free assemblage.•Solubility of SiO2 in Cpx increases with pressure and with Fe/(Fe+Mg) of the bulk.•Cpx forms the solid solution series of Es–Jd and Es–Px, rather than Jd–Ts and Es–Ts joins at UHPM conditions.•Our data suggest the existence of octahedral Si incorporating the M2 vacancies in Cpx.
Glycans are known as the third major class of biopolymers, next to DNA and proteins. They cover the surfaces of many cells, serving as the 'face' of cells, whereby other biomolecules and viruses ...interact. The structure of glycans, however, differs greatly from DNA and proteins in that they are branched, as opposed to linear sequences of amino acids or nucleotides. Therefore, the storage of glycan information in databases, let alone their curation, has been a difficult problem. This has caused many duplicated efforts when integration is attempted between different databases, making an international repository for glycan structures, where unique accession numbers are assigned to every identified glycan structure, necessary. As such, an international team of developers and glycobiologists have collaborated to develop this repository, called GlyTouCan and is available at http://glytoucan.org/, to provide a centralized resource for depositing glycan structures, compositions and topologies, and to retrieve accession numbers for each of these registered entries. This will thus enable researchers to reference glycan structures simply by accession number, as opposed to by chemical structure, which has been a burden to integrate glycomics databases in the past.
Cartilage damage may eventually lead to osteoarthritis because it is difficult to repair. Human-induced pluripotent stem cell (iPSC)-derived chondrocytes may potentially be used to treat cartilage ...damage, but the tumorigenicity of iPSCs is a major concern for their application in regenerative medicine. Many glycoconjugates serve as stem cell markers, and glycosphingolipids (GSLs) including H type 1 antigen (Fucα1-2Galβ1-3GlcNAc) have been expressed on the surface of iPSCs. The purpose of the present study was to investigate whether GSL-glycome analysis is useful for quality control of residual iPSCs in chondrocytes. We performed GSL-glycome analysis of undifferentiated iPSCs in chondrocytes by combining glycoblotting and aminolysis-sialic acid linkage-specific alkylamidation (SALSA) method, enabling the detection of small quantities of iPSC-specific GSL-glycans from 5 × 10
cells. Furthermore, we estimated the residual amount of iPSCs using R-17F antibody, which possesses cytotoxic activity toward iPSCs that is dependent on the Lacto-
-fucopentaose I (LNFP I) of GSL. Moreover, we could detect a small number of LNFP I during mesenchymal stem cells (MSCs) differentiation from iPSCs. This is the first demonstration that GSL-glycome analysis is useful for detecting undifferentiated iPSCs, and can thereby support safe regenerative medicine.
We propose a Ti–in–garnet thermometer for ultrahigh–temperature granulites calibrated from experimentally reversed data of the TiO2 solubility in garnet coexisting with orthopyroxene, rutile and ...quartz at pressures 7–23 kbar and temperatures 850–1300 °C. We confirm that the combined substitution TiVIAlIV ⇌ AlVISiIV, quasi–chemically equivalent to Ti ⇌ Si, is predominant rather than the coupled substitution MVITiVI ⇌ AlVIAlVI (M: Ca, Mg, Fe). The chemical formula of Ca– and Ti–poor garnet under ultrahigh–temperature metamorphic conditions can be expressed as M3Al2Si3−xTixO12, which indicates that the relation NSi + NTi = 3 is not an evidence of TiIV ⇌ SiIV. The TiO2 content of garnet increases with temperature and pressure, though the pressure dependence is small, as is given by the following equation: where N is the number of cation per formula unit based on a 12–oxygen atom normalisation. Temperature T and pressure P are given in Kelvin and kbar, respectively. The present thermometer is useful to estimate metamorphic conditions. This new thermometer is applied to natural garnet in geologically and petrologically well–characterised Antarctic ultrahigh–temperature granulites. The resultant pressure and temperature estimates are consistent with those reported from granulites of these areas.
We have generated a mouse monoclonal antibody (R-17F, IgG1 subtype) specific to human induced pluripotent stem (hiPS)/embryonic stem (ES) cells by using a hiPS cell line as an antigen. Triple-color ...confocal immunostaining images of hiPS cells with R-17F indicated that the R-17F epitope was expressed exclusively and intensively on the cell membranes of hiPS cells and co-localized partially with those of SSEA-4 and SSEA-3. Lines of evidence suggested that the predominant part of the R-17F epitope was a glycolipid. Upon TLC blot of total lipid extracts from hiPS cells with R-17F, one major R-17F-positive band was observed at a slow migration position close to that of anti-blood group H1(O) antigen. MALDI-TOF-MS and MSn analyses of the purified antigen indicated that the presumptive structure of the R-17F antigen was Fuc-Hex-HexNAc-Hex-Hex-Cer. Glycan microarray analysis involving 13 different synthetic oligosaccharides indicated that R-17F bound selectively to LNFP I (Fucα1–2Galβ1–3GlcNAcβ1–3Galβ1–4Glc). A critical role of the terminal Fucα1–2 residue was confirmed by the selective disappearance of R-17F binding to the purified antigen upon α1–2 fucosidase digestion. Most interestingly, R-17F, when added to hiPS/ES cell suspensions, exhibited potent dose-dependent cytotoxicity. The cytotoxic effect was augmented markedly upon the addition of the secondary antibody (goat anti-mouse IgG1 antibody). R-17F may be beneficial for safer regenerative medicine by eliminating residual undifferentiated hiPS cells in hiPS-derived regenerative tissues, which are considered to be a strong risk factor for carcinogenesis.
Background: Carbohydrate epitopes are often used as markers for characterization of hiPS cells.
Results: A mouse IgG1 antibody (R-17F) was raised using hiPS cells as an antigen.
Conclusion: R-17F recognizes lacto-N-fucopentaose I on glycolipid and exhibits a cytotoxic effect on hiPS/ES cells.
Significance: R-17F may be beneficial for safer regenerative medicine by eliminating residual undifferentiated hiPS/ES cells, which are a risk factor for carcinogenesis.
Function of lectin depends on its amino acid sequence of carbohydrate-recognition domain (CRD), conformation, and extracellular/intracellular localization. Altering lectin gene expression by ...over-expression or knockdown is a powerful tool for analyzing its cellular function. Here, we describe a method of lectin gene over-expression, taking a C-type lectin, mannan-binding protein (MBP), as an example. Carbohydrate-binding ability of MBP, its subcellular localization, and functional co-localization with ligand glycoprotein are assayed comparing with an inactive mutant MBP.
FeAlO3a) was synthesized under ultrahigh–temperature metamorphic conditions. The assemblage of FeAlO3, SiO2–rich melt and vapor was obtained from a mixture of Rundvågshetta sillimanite and ...reagent–grade Fe2O3 (weight ratio of 95:5) in Pt capsules at pressures of 5 and 9 kbar and a temperature of 1050 °C under hydrous conditions. No hematite was found in these runs. Corundum was a rare crystallization product in the 9 kbar experiment. We also produced FeAlO3, SiO2–rich melt and vapor in the sillimanite–Fe3O4 (weight ratio of 86:14) system in a AuPd capsule at 9 kbar and 1050 °C under hydrous condition. A crystal domain comprising FeAlO3, corundum, magnetite–hercynite spinel and ulvöspinel formed at the bottom part of the charge due to contamination by Ti from titanium oxide, probably rutile, included within the sillimanite. This domain was in contact with melt among sillimanite crystals. Our results suggest that FeAlO3 would be an index mineral for ultrahigh–temperature metamorphism of partially melted Fe– and Al–rich granulites generated under hydrous and oxidizing conditions. a) FeAlO3 is used for both composition and phase in this paper.
We developed two human-induced pluripotent stem cell (hiPSC)/human embryonic stem cell (hESC)-specific glycan-recognizing mouse antibodies, R-10G and R-17F, using the Tic (JCRB1331) hiPSC line as an ...antigen. R-10G recognizes a low-sulfate keratan sulfate, and R-17F recognizes lacto-N-fucopentaose-1. To evaluate the general characteristics of stem cell glycans, we investigated the hiPSC line 201B7 (HPS0063), a prototype iPSC line. Using an R-10G affinity column, an R-10G-binding protein was isolated from 201B7 cells. The protein yielded a single but very broad band from 480 to 1236 kDa by blue native gel electrophoresis. After trypsin digestion, the protein was identified as podocalyxin by liquid chromatography/mass spectrometry. According to Western blotting, the protein reacted with R-10G and R-17F. The R-10G-positive band was resistant to digestion with glycan-degrading enzymes, including peptide N-glycanase, but the intensity of the band was decreased significantly by digestion with keratanase, keratanase II, and endo-β-galactosidase, suggesting the R-10G epitope to be a keratan sulfate. These results suggest that keratan sulfate-type epitopes are shared by hiPSCs. However, the keratan sulfate from 201B7 cells contained a polylactosamine disaccharide unit (Galβ1-4GlcNAc) at a significant frequency, whereas that from Tic cells consisted mostly of keratan sulfate disaccharide units (Galβ1-4GlcNAc(6S)). In addition, the abundance of the R-10G epitope was significantly lower in 201B7 cells than in Tic cells.
PDF
