New polymorph of InVO4: A high-pressure structure with six-coordinated vanadium

This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in Inorganic Chemestry, copyright © American Chemical Society after peer review. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/ic402043xA new wolframite-type polymorph of InVO4 is identified under compression near 7 GPa by in situ high-pressure (HP) X-ray diffraction (XRD) and Raman spectroscopic investigations on the stable orthorhombic InVO4. The structural transition is accompanied by a large volume collapse (Delta V/V = -14%) and a drastic increase in bulk modulus (from 69 to 168 GPa). Both techniques also show the existence of a third phase coexisting with the low- and high-pressure phases in a limited pressure range close to the transition pressure. XRD studies revealed a highly anisotropic compression in orthorhombic InVO4. In addition, the compressibility becomes nonlinear in the HP polymorph. The volume collapse in the lattice is related to an increase of the polyhedral coordination around the vanadium atoms. The transformation is not fully reversible. The drastic change in the polyhedral arrangement observed at the transition is indicative of a reconstructive phase transformation. The HP phase here found is the only modification of InVO4 reported to date with 6-fold coordinated vanadium atoms. Finally, Raman frequencies and pressure coefficients in the low- and high-pressure phases of InVO4 are reported.This research supported by the Spanish government MINECO under Grant Nos. MAT2010-21270-C04-01/04 and CSD2007-00045. O.G. acknowledges support from Vicerrectorado de Investigacion y Desarrollo of UPV (Grant No. UPV2011-0914 PAID-05-11 and UPV2011-0966 PAID-06-11). S.N.A. acknowledges support provided by Universitat de Valencia during his visit to it. B.G.-D. acknowledges the financial support from MINECO through the FPI program.Errandonea, D.; Gomis Hilario, O.; García-Domene, B.; Pellicer Porres, J.; Katari, V.; Achary, SN.; Tyagi, AK.... (2013). New polymorph of InVO4: A high-pressure structure with six-coordinated vanadium. Inorganic Chemistry. 52(21):12790-12798. https://doi.org/10.1021/ic402043xS1279012798522

Raman scattering study of bulk and nanocrystalline PbMoO4 at high pressures

High-pressure Raman scattering measurements have been performed in wulfenite (PbMoO4) for both bulk and nanocrystalline powders up to 22 GPa. Our Raman scattering measurements evidence the phase transition from the tetragonal scheelite structure to the monoclinic M-fergusonite structure in both bulk and nanocrystalline powders above 10.8 and 13.4 GPa, respectively. The pressure dependences of the Raman active modes in both structures were compared and discussed based on our theoretical results obtained from lattice dynamics ab initio calculations. © 2012 American Institute of Physics.Financial support from the Spanish ConsoliderIngenio 2010 Program (Project No. CDS2007-00045) is acknowledged. The work was also supported by Spanish MICINN under Projects MAT2010-21270-C04-01/03/04 and from Vicerrectorado de Investigacion de la Universitat Politecnica de Valencia under Projects UPV2011-0914PAID-05-11 and UPV2011-0914 PAID-05-11. Supercomputer time has been provided by the Red Espanola de Supercomputacion (RES) and the MALTA cluster.Vilaplana Cerda, RI.; Gomis Hilario, O.; Manjón Herrera, FJ.; Rodríguez-Hernández, P.; Muñoz, A.; Errandonea, D.; Achary, S.... (2012). Raman scattering study of bulk and nanocrystalline PbMoO4 at high pressures. Journal of Applied Physics. 112:1035101-10351010. doi:10.1063/1.4765717S103510110351010112Pinnow, D. A., Van Uitert, L. G., Warner, A. W., & Bonner, W. A. (1969). LEAD MOLYBDATE: A MELT‐GROWN CRYSTAL WITH A HIGH FIGURE OF MERIT FOR ACOUSTO‐OPTIC DEVICE APPLICATIONS. Applied Physics Letters, 15(3), 83-86. doi:10.1063/1.1652917Coquin, G. A., Pinnow, D. A., & Warner, A. W. (1971). Physical Properties of Lead Molybdate Relevant to Acousto‐Optic Device Applications. Journal of Applied Physics, 42(6), 2162-2168. doi:10.1063/1.1660520Minowa, M., Itakura, K., Moriyama, S., & Ootani, W. (1992). Measurement of the property of cooled lead molybdate as a scintillator. 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High-pressure Raman study of SrMoO4 up to 37 GPa and pressure-induced phase transitions. Journal of Raman Spectroscopy, 26(6), 451-455. doi:10.1002/jrs.1250260609Christofilos, D., Arvanitidis, J., Kampasakali, E., Papagelis, K., Ves, S., & Kourouklis, G. A. (2004). High pressure Raman study of BaMoO4. physica status solidi (b), 241(14), 3155-3160. doi:10.1002/pssb.200405234Panchal, V., Garg, N., & Sharma, S. M. (2006). Raman and x-ray diffraction investigations on BaMoO4under high pressures. Journal of Physics: Condensed Matter, 18(16), 3917-3929. doi:10.1088/0953-8984/18/16/002Errandonea, D., Kumar, R. S., Ma, X., & Tu, C. (2008). High-pressure X-ray diffraction study of SrMoO4 and pressure-induced structural changes. Journal of Solid State Chemistry, 181(2), 355-364. doi:10.1016/j.jssc.2007.12.010Errandonea, D., Santamaria-Perez, D., Achary, S. N., Tyagi, A. K., Gall, P., & Gougeon, P. (2011). High-pressure x-ray diffraction study of CdMoO4 and EuMoO4. Journal of Applied Physics, 109(4), 043510-043510-5. doi:10.1063/1.3553850Ganguly, B. N., & Nicol, M. (1977). Effect of hydrostatic pressure on the vibrational properties and the structure of SrWO4 and PbMoO4. Physica Status Solidi (b), 79(2), 617-622. doi:10.1002/pssb.2220790227Hazen, R. M., Finger, L. W., & Mariathasan, J. W. E. (1985). High-pressure crystal chemistry of scheelite-type tungstates and molybdates. Journal of Physics and Chemistry of Solids, 46(2), 253-263. doi:10.1016/0022-3697(85)90039-3Jayaraman, A., Batlogg, B., & VanUitert, L. G. (1985). Effect of high pressure on the Raman and electronic absorption spectra ofPbMoO4andPbWO4. Physical Review B, 31(8), 5423-5427. doi:10.1103/physrevb.31.5423Errandonea, D., Santamaria-Perez, D., Grover, V., Achary, S. N., & Tyagi, A. K. (2010). High-pressure x-ray diffraction study of bulk and nanocrystalline PbMoO4. Journal of Applied Physics, 108(7), 073518. doi:10.1063/1.3493048Syassen, K. (2008). Ruby under pressure. 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Wheat genetic resources have avoided disease pandemics, improved food security, and reduced environmental footprints: A review of historical impacts and future opportunities

The use of plant genetic resources (PGR)—wild relatives, landraces, and isolated breeding gene pools—has had substantial impacts on wheat breeding for resistance to biotic and abiotic stresses, while increasing nutritional value, end-use quality, and grain yield. In the Global South, post-Green Revolution genetic yield gains are generally achieved with minimal additional inputs. As a result, production has increased, and millions of hectares of natural ecosystems have been spared. Without PGR-derived disease resistance, fungicide use would have easily doubled, massively increasing selection pressure for fungicide resistance. It is estimated that in wheat, a billion liters of fungicide application have been avoided just since 2000. This review presents examples of successful use of PGR including the relentless battle against wheat rust epidemics/pandemics, defending against diseases that jump species barriers like blast, biofortification giving nutrient-dense varieties and the use of novel genetic variation for improving polygenic traits like climate resilience. Crop breeding genepools urgently need to be diversified to increase yields across a range of environments (>200 Mha globally), under less predictable weather and biotic stress pressure, while increasing input use efficiency. Given that the ~0.8 m PGR in wheat collections worldwide are relatively untapped and massive impacts of the tiny fraction studied, larger scale screenings and introgression promise solutions to emerging challenges, facilitated by advanced phenomic and genomic tools. The first translocations in wheat to modify rhizosphere microbiome interaction (reducing biological nitrification, reducing greenhouse gases, and increasing nitrogen use efficiency) is a landmark proof of concept. Phenomics and next-generation sequencing have already elucidated exotic haplotypes associated with biotic and complex abiotic traits now mainstreamed in breeding. Big data from decades of global yield trials can elucidate the benefits of PGR across environments. This kind of impact cannot be achieved without widescale sharing of germplasm and other breeding technologies through networks and public–private partnerships in a pre-competitive space

Effects of Single Nucleotide Polymorphisms on Human N-Acetyltransferase 2 Structure and Dynamics by Molecular Dynamics Simulation

BACKGROUND: Arylamine N-acetyltransferase 2 (NAT2) is an important catalytic enzyme that metabolizes the carcinogenic arylamines, hydrazine drugs and chemicals. This enzyme is highly polymorphic in different human populations. Several polymorphisms of NAT2, including the single amino acid substitutions R64Q, I114T, D122N, L137F, Q145P, R197Q, and G286E, are classified as slow acetylators, whereas the wild-type NAT2 is classified as a fast acetylator. The slow acetylators are often associated with drug toxicity and efficacy as well as cancer susceptibility. The biological functions of these 7 mutations have previously been characterized, but the structural basis behind the reduced catalytic activity and reduced protein level is not clear. METHODOLOGY/PRINCIPAL FINDINGS: We performed multiple molecular dynamics simulations of these mutants as well as NAT2 to investigate the structural and dynamical effects throughout the protein structure, specifically the catalytic triad, cofactor binding site, and the substrate binding pocket. None of these mutations induced unfolding; instead, their effects were confined to the inter-domain, domain 3 and 17-residue insert region, where the flexibility was significantly reduced relative to the wild-type. Structural effects of these mutations propagate through space and cause a change in catalytic triad conformation, cofactor binding site, substrate binding pocket size/shape and electrostatic potential. CONCLUSIONS/SIGNIFICANCE: Our results showed that the dynamical properties of all the mutant structures, especially in inter-domain, domain 3 and 17-residue insert region were affected in the same manner. Similarly, the electrostatic potential of all the mutants were altered and also the functionally important regions such as catalytic triad, cofactor binding site, and substrate binding pocket adopted different orientation and/or conformation relative to the wild-type that may affect the functions of the mutants. Overall, our study may provide the structural basis for reduced catalytic activity and protein level, as was experimentally observed for these polymorphisms

Overexpression of Myocilin in the Drosophila Eye Activates the Unfolded Protein Response: Implications for Glaucoma

Glaucoma is the world's second leading cause of bilateral blindness with progressive loss of vision due to retinal ganglion cell death. Myocilin has been associated with congenital glaucoma and 2-4% of primary open angle glaucoma (POAG) cases, but the pathogenic mechanisms remain largely unknown. Among several hypotheses, activation of the unfolded protein response (UPR) has emerged as a possible disease mechanism.We used a transgenic Drosophila model to analyze whole-genome transcriptional profiles in flies that express human wild-type or mutant MYOC in their eyes. The transgenic flies display ocular fluid discharge, reflecting ocular hypertension, and a progressive decline in their behavioral responses to light. Transcriptional analysis shows that genes associated with the UPR, ubiquitination, and proteolysis, as well as metabolism of reactive oxygen species and photoreceptor activity undergo altered transcriptional regulation. Following up on the results from these transcriptional analyses, we used immunoblots to demonstrate the formation of MYOC aggregates and showed that the formation of such aggregates leads to induction of the UPR, as evident from activation of the fluorescent UPR marker, xbp1-EGFP. CONCLUSIONS / SIGNIFICANCE: Our results show that aggregation of MYOC in the endoplasmic reticulum activates the UPR, an evolutionarily conserved stress pathway that culminates in apoptosis. We infer from the Drosophila model that MYOC-associated ocular hypertension in the human eye may result from aggregation of MYOC and induction of the UPR in trabecular meshwork cells. This process could occur at a late age with wild-type MYOC, but might be accelerated by MYOC mutants to account for juvenile onset glaucoma

Biotechnological Perspective of Reactive Oxygen Species (ROS)-Mediated Stress Tolerance in Plants

All environmental cues lead to develop secondary stress conditions like osmotic and oxidative stress conditions that reduces average crop yields by more than 50% every year. The univalent reduction of molecular oxygen (O2) in metabolic reactions consequently produces superoxide anions (O2•−) and other reactive oxygen species (ROS) ubiquitously in all compartments of the cell that disturbs redox potential and causes threat to cellular organelles. The production of ROS further increases under stress conditions and especially in combination with high light intensity. Plants have evolved different strategies to minimize the accumulation of excess ROS like avoidance mechanisms such as physiological adaptation, efficient photosystems such as C4 or CAM metabolism and scavenging mechanisms through production of antioxidants and antioxidative enzymes. Ascorbate-glutathione pathway plays an important role in detoxifying excess ROS in plant cells, which includes superoxide dismutase (SOD) and ascorbate peroxidase (APX) in detoxifying O2•−radical and hydrogen peroxide (H2O2) respectively, monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR) and glutathione reductase (GR) involved in recycling of reduced substrates such as ascorbate and glutathione. Efficient ROS management is one of the strategies used by tolerant plants to survive and perform cellular activities under stress conditions. The present chapter describes different sites of ROS generation and and their consequences under abiotic stress conditions and also described the approaches to overcome oxidative stress through genomics and genetic engineering

Antimutagenic compounds and their possible mechanisms of action

Mutagenicity refers to the induction of permanent changes in the DNA sequence of an organism, which may result in a heritable change in the characteristics of living systems. Antimutagenic agents are able to counteract the effects of mutagens. This group of agents includes both natural and synthetic compounds. Based on their mechanism of action among antimutagens, several classes of compounds may be distinguished. These are compounds with antioxidant activity; compounds that inhibit the activation of mutagens; blocking agents; as well as compounds characterized with several modes of action. It was reported previously that several antitumor compounds act through the antimutagenic mechanism. Hence, searching for antimutagenic compounds represents a rapidly expanding field of cancer research. It may be observed that, in recent years, many publications were focused on the screening of both natural and synthetic compounds for their beneficial muta/antimutagenicity profile. Thus, the present review attempts to give a brief outline on substances presenting antimutagenic potency and their possible mechanism of action. Additionally, in the present paper, a screening strategy for mutagenicity testing was presented and the characteristics of the most widely used antimutagenicity assays were described