Al-induced root cell wall chemical components differences of wheat (Triticum aestivum L.) differing in Al tolerance

Root growth is different in plants with different levels of Al-tolerance under Al stress. Cell wall chemical components of root tip cell are related to root growth. The aim of this study was to explore the relationship between root growth difference and cell wall chemical components. For this purpose, the cell wall chemical components of root tip cell in two near-isogenic lines (NIL) wheat (Triticum aestivum L.), ET8 (Al-tolerant) and ES8 (Al-sensitive) were investigated. In ET8 and ES8, after treatments with Al (50 μM), relative root elongation (RRE) and relative cell length (RCL) decreased with time increase (6, 12 and 24 h), but was more significant in ES8. There was a good correlation between RRE and RCL (R2= 0.866). Activities of the metabolism enzyme of cell wall chemical components varied, for example, phenylalanine ammonia-lyase (PAL, EC 4.3.1.5), cinnamyl alcohol dehydrogenase (CAD, EC 1.1.1.195) and peroxidase (POD, EC 1.11.1) increased; and activities of callase (EC 3.2.1.39), cellulase (EC 3.2.1.4) decreased. Cell wall chemical contents of lignin, H2O2 and callose increased and contents of cellulose decreased. Changes of enzyme activities and cell wall chemical components were significant in both lines, but were more prominent in the ES8 line. The analysis indicated that under Al stress, differences in cell wall chemical components of root tip cell between wheat lines with different Al tolerances induce the root tip elongation differences, thereby causing different root growth.Key words: Aluminum toxicity, callose, cellulose, hydrogen peroxide, lignin, wheat

First-principles calculations of phonon and thermodynamic properties of AlRE (RE= Y, Gd, Pr, Yb) intermetallic compounds

The phonon and thermodynamic properties of rare-earth-aluminum intermetallics AlRE (RE=Y, Gd, Pr, Yb) with B2-type structure are investigated by performing density functional theory and density functional perturbation theory within the quasiharmonic approximation. The phonon spectra and phonon density of states, including the phonon partial density of states and total density of states, have been discussed. Our results demonstrate that the density of states is mostly composed of Al states at the high frequency. The temperature dependence of various quantities such as the thermal expansions, the heat capacities at constant volume and constant pressure, the isothermal bulk modulus, and the entropy are obtained. The electronic contribution to the specific heat is discussed, and the presented results show that the thermal electronic excitation affecting the thermal properties is inessential.Comment: 17 pages,8 figure

Rapid Host Defense against Aspergillus fumigatus Involves Alveolar Macrophages with a Predominance of Alternatively Activated Phenotype

The ubiquitous fungus Aspergillus fumigatus is associated with chronic diseases such as invasive pulmonary aspergillosis in immunosuppressed patients and allergic bronchopulmonary aspergillosis (ABPA) in patients with cystic fibrosis or severe asthma. Because of constant exposure to this fungus, it is critical for the host to exercise an immediate and decisive immune response to clear fungal spores to ward off disease. In this study, we observed that rapidly after infection by A. fumigatus, alveolar macrophages predominantly express Arginase 1 (Arg1), a key marker of alternatively activated macrophages (AAMs). The macrophages were also found to express Ym1 and CD206 that are also expressed by AAMs but not NOS2, which is expressed by classically activated macrophages. The expression of Arg1 was reduced in the absence of the known signaling axis, IL-4Rα/STAT6, for AAM development. While both Dectin-1 and TLR expressed on the cell surface have been shown to sense A. fumigatus, fungus-induced Arg1 expression in CD11c+ alveolar macrophages was not dependent on either Dectin-1 or the adaptor MyD88 that mediates intracellular signaling by most TLRs. Alveolar macrophages from WT mice efficiently phagocytosed fungal conidia, but those from mice deficient in Dectin-1 showed impaired fungal uptake. Depletion of macrophages with clodronate-filled liposomes increased fungal burden in infected mice. Collectively, our studies suggest that alveolar macrophages, which predominantly acquire an AAM phenotype following A. fumigatus infection, have a protective role in defense against this fungus

Using a fast hybrid pixel detector for dose-efficient diffraction imaging beam-sensitive organic molecular thin films

We discuss the benefits and showcase the applications of using a fast, hybrid-pixel detector (HPD) for 4D-STEM experiments and emphasize that in diffraction imaging the structure of molecular nano-crystallites in organic solar cell thin films with a dose-efficient modality 4D-scanning confocal electron diffraction (4D-SCED). With 4D-SCED, spot diffraction patterns form from an interaction area of a few nm while the electron beam rasters over the sample, resulting in high dose effectiveness yet highly demanding on the detector in frame speed, sensitivity, and single-pixel count rate. We compare the datasets acquired with 4D-SCED using a fast HPD with those using state-of-the-art complementary metal-oxide-semiconductor (CMOS) cameras to map the in-plane orientation of π -stacking nano-crystallites of small molecule DRCN5T in a blend of DRCN5T: PC _71 BM after solvent vapor annealing. The high-speed CMOS camera, using a scintillator optimized for low doses, showed impressive results for electron sensitivity and low noise. However, the limited speed restricted practical experimental conditions and caused unintended damage to small and weak nano-crystallites. The fast HPD, with a speed three orders of magnitude higher, allows a much higher probe current yet a lower total dose on the sample, and more scan points cover a large field of view in less time. A lot more faint diffraction signals that correspond to just a few electron events are detected. The improved performance of direct electron detectors opens more possibilities to enhance the characterization of beam-sensitive materials using 4D-STEM techniques

Open Apatite Sr Isotopic System in Low-Temperature Hydrous Regimes

Single crystal in situ Sr and Nd isotopic analysis of apatite permits more accurate interrogation of a variety of geoscience questions, including provenance, petrogenesis, and ore system evolution. However, the degree to which the apatite Sr and Nd isotopic systems remain closed under extended low-temperature hydrous conditions is not well constrained. Granitoids at the Baogutu deposit in NW China contain veins of low-temperature H2O-rich epistilbite and thus provide an excellent opportunity to evaluate isotopic system integrity under low-temperature hydrous conditions. Apatite from the Late Carboniferous diorite and granodiorite porphyry show variable (87Sr/86Sr)i ratios (0.7042 to 0.7062) but restricted εNd(t) values (+7.0±0.4 and +6.5±0.4, 1σ). The apatite Sr isotope signatures are transitional between whole rock (0.7035) and vein epistilbite (~0.7062), indicating apparent incorporation of radiogenic Sr from the epistilbite-related hydrothermal fluid into the igneous apatite, whereas εNd values closely match those of the whole rock (+6.9±0.2 and +6.5±0.2, 1σ) and epistilbite (+6.2±0.2, 1σ). Obvious metasomatic textures of apatite were revealed by cathodoluminescence images. The 260 to 300°C formation temperatures for earlier quartz-sulfide veins and chlorite alteration and homogenization temperature (~190°C) of fluid inclusions in epistilbite-calcite vein calcite constrain the temperature of the later epistilbite-related hydrothermal fluid to 190 to 260°C. These results indicate that Sr and likely Nd isotopes in apatite are mobile under low-temperature (<300°C) hydrous conditions and implies that Rb-Sr signatures in apatite from hydrothermally altered rocks reveal the presence and characteristics of modifying fluids

Geochronology, geochemistry, and zircon Hf isotopic compositions of Mesozoic intermediate-felsic intrusions in central Tibet: Petrogenetic and tectonic implications

Mesozoic intermediate-felsic intrusions are widely distributed in the southern Qiangtang terrane, central Tibet. Zircon U-Pb dating shows that these intrusions formed in two periods in the Jurassic (169-150Ma) and Cretaceous (127-113Ma). They mostly belong to the high-K calc-alkaline series, and show strong enrichments in large ion lithophile elements (e.g., Cs, Rb, and K), depletions in Nb, Ta, and Ti, and negative Ba anomalies on primitive mantle-normalized diagrams. P2O5 contents decrease with increasing SiO2 content, and Th contents increase with increasing Rb content, consistent with the evolution trend of I-type magmas. These intrusions show a wide range of zircon eHf(t) values from -19.4 to 11.2, including in rocks with similar SiO2 contents, suggesting variable contributions from mantle and Qiangtang crustal sources. Fine-grained mafic to intermediate igneous enclaves in Jurassic intrusions have similar zircon U-Pb ages and similar or slightly higher zircon eHf(t) values to the host rocks, suggesting that the enclave magmas were derived from mixed magmas at depth and injected into more evolved magmas in upper crustal magma chambers. Magma mixing is also supported by the wide range of zircon Hf isotopic compositions (eHf(t)=-19.4 to 2.5) from within individual Jurassic and Cretaceous intrusions, and Jurassic enclaves. The Jurassic-Cretaceous magmas likely formed in a continental arc setting during subduction of the Bangong-Nujiang ocean between 170 and 110Ma, and evolved in the upper plate crust by MASH processes. © 2014 Elsevier B.V

Mineralogical evidence for crystallization conditions and petrogenesis of ilmenite-series I-type granitoids at the Baogutu reduced porphyry Cu deposit (Western Junggar, NW China): Mössbauer spectroscopy, EPM and LA-(MC)-ICPMS analyses

© 2017 Elsevier B.V.Primary ore-forming minerals retain geochemical signatures of magmatic crystallization information and can reveal the petrochemical conditions prevalent at the time of their formation. The Baogutu deposit is a typical reduced porphyry Cu deposit. Amphibole and biotite Fe3+/SFe ratios, minerals (feldspar, biotite, amphibole, zircon and apatite), in situ elemental and apatite Nd isotopic compositions were determined by Mössbauer spectroscopy, electron probe microanalysis, and laser ablation multiple-collection inductively coupled plasma mass spectrometry, respectively, to investigate the magma oxidation state, petrogenesis, source features, and to constrain the carbon species at magmatic stages for the intrusive phases. The results show that the primary plagioclase and amphibole in the mineralized diorite to granodiorite porphyry and post ore hornblende diorite porphyry are distinct (An26-55 versus An60-69; Mg-hornblende versus tschermakite). In particular, the amphibole shows distinct major and trace element compositions with light rare earth element enrichments and negative Eu anomalies in Mg-hornblende and light rare earth element depletions and no Eu anomalies in tschermakite. All the analyzed biotites are primary igneous phases with a biotite phenocryst profile showing significant variations of Zn, Cr, Sc and Sr from core to rim. These results may indicate the occurrence of mixing between two distinct magmas during mineral formation. Titanium in zircon and Si* in amphibole thermometries indicate that magma crystallized at &gt;900 °C and continued to ~650 °C. In situ apatite Nd isotope (eNd(t) = 5.6–7.6, TDM2 = 620–460 Ma), indicate absence of significant reduced sedimentary contamination and the source of juvenile lower crust. Slightly decreasing Fe3+/SFe ratios from biotite and amphibole to whole rock indicate decreasing oxygen fugacity during magma crystallization. Recalculated biotite compositions according to Fe3+/SFe ratios indicate fO2 values of less than Ni-NiO buffer (NNO) which show slightly lower values than that estimated according to zircon/melt distribution coefficients Ce anomalies (~?NNO + 0.6). These values are consistent with the features of reduced porphyry Cu deposits. Crystallization of other mineral phases significantly affects the reliability of oxybarometer of zircon/melt distribution coefficients Eu anomalies and Mn contents in apatite. This oxidation state suggests that only CO2 was present at the magmatic stage, and implies that CH4 formed during CO2 reduction occurring later hydrothermal alteration. The alteration of primary amphibole to actinolite released Ti, Al, Fe, Mn, Na and K to the fluid with later precipitation of titanite, albite and minor ilmenite and magnetite during actinolite alteration