Organic molecular and inorganic isotope records of Cenozoic topography, ecosystem and climate evolution of the Southern Central Andes

The Andes are part of the longest mountain range on earthand their evolution has influenced global climate,weathering, and ecosystems since the Cretaceous. Weanalyzed the distribution and δ2H and δ13C of plant-derivedorganic biomarkers, the δ2H of volcanic glass, and thedistribution of soil-derived glycerol dialkyl glyceroltetraethers from Cenozoic sediments in the Malargüe Basinof Argentina (~35°S). Organic molecular and inorganic datawere measured to reconstruct Cenozoic changes inprecipitation isotopes, temperature, moisture deficit, andecosystems on the eastern flank of the Southern CentralAndes. Two variables (precipitation isotopes andtemperature) are strongly related to the topography of anorogen through isotopic distillation of precipitation duringrainout and changes in temperature with elevation.However, molecular biomarkers also provide keyinformation about climate and aridity through time. Weshow that organic biomarker and volcanic glass δ2H datafrom the Malargüe basin record late Cenozoic reduction oforographic lifting of airmasses associated with localdowndrop of the basin. In addition, molecular data reflectlong-term shifts in moisture deficit and plant water stressthat are consistent with regional patterns of changingclimate and aridity due to late Cenozoic cooling. Soilderivedtetraether lipid records mirror the patterns observedin organic molecular and inorganic isotope data, yet recordtemperatures that are unrealistic. These data highlight thecomplexity of universally applying the soil GDGT proxy toall terrestrial systems. In total, combined organic andinorganic data highlight the importance of multi-proxyrecords to produce a coherent representation of long-termecosystem and climate change in a region impacted byevolving climatic and tectonic boundary conditions.Fil: Hren, Michael. University of Connecticut; Estados UnidosFil: Brandon, Mark Thomas. University of Yale; Estados UnidosFil: Fennell, Lucas Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Smolen, Jonathan. University of Connecticut; Estados UnidosFil: Super, James. University of Yale; Estados UnidosGoldschmidt MeetingEstados UnidosGeochemical SocietyEuropean Association of Geochemistr

PfeIK1, a eukaryotic initiation factor 2α kinase of the human malaria parasite Plasmodium falciparum, regulates stress-response to amino-acid starvation

<p>Abstract</p> <p>Background</p> <p>Post-transcriptional control of gene expression is suspected to play an important role in malaria parasites. In yeast and metazoans, part of the stress response is mediated through phosphorylation of eukaryotic translation initiation factor 2α (eIF2α), which results in the selective translation of mRNAs encoding stress-response proteins.</p> <p>Methods</p> <p>The impact of starvation on the phosphorylation state of PfeIF2α was examined. Bioinformatic methods were used to identify plasmodial eIF2α kinases. The activity of one of these, PfeIK1, was investigated using recombinant protein with non-physiological substrates and recombinant PfeIF2α. Reverse genetic techniques were used to disrupt the <it>pfeik1 </it>gene.</p> <p>Results</p> <p>The data demonstrate that the <it>Plasmodium falciparum </it>eIF2α orthologue is phosphorylated in response to starvation, and provide bioinformatic evidence for the presence of three eIF2α kinases in <it>P. falciparum</it>, only one of which (PfPK4) had been described previously. Evidence is provided that one of the novel eIF2α kinases, PfeIK1, is able to phosphorylate the <it>P. falciparum </it>eIF2α orthologue <it>in vitro</it>. PfeIK1 is not required for asexual or sexual development of the parasite, as shown by the ability of <it>pfeik1</it>^-parasites to develop into sporozoites. However, eIF2α phosphorylation in response to starvation is abolished in <it>pfeik1</it>^-asexual parasites</p> <p>Conclusion</p> <p>This study strongly suggests that a mechanism for versatile regulation of translation by several kinases with a similar catalytic domain but distinct regulatory domains, is conserved in <it>P. falciparum</it>.</p

The Magnetic Phase Transition and Universality Class of h-YMnO3 and h-(Y0.98Eu0.02)MnO3 Under Zero and Applied Pressure

We investigated the antiferromagnetic phase transition in the frustrated and multiferroic hexagonal manganites h-YMnO3 (YMO) and h-(Y0.98Eu0.02)MnO3 (YEMO). Elastic neutron scattering was used to study, in detail, the phase transition in YMO and YEMO under zero pressure and in YMO under a hydrostatic pressure of 1.5 GPa. Under conditions of zero pressure, we found critical temperatures of TN = 71.3(1) K and 72.11(5) K and the critical exponent 0.22(2) and b = 0.206(3), for YMO and YEMO, respectively. This is in agreement with earlier work by Roessli et al. Under an applied hydrostatic pressure of 1.5 GPa, the ordering temperature increased to TN = 75.2(5) K, in agreement with earlier reports, while b was unchanged. Inelastic neutron scattering was used to determine the size of the anisotropy spin wave gap close to the phase transition. From spin wave theory, the gap is expected to close with a critical exponent, b0, identical to the order parameter b. Our results indicate that the gap in YEMO indeed closes at TN = 72.4(3) K with b0 = 0.24(2), while the in-pressure gap in YMO closes at 75.2(5) K with an exponent of b0 = 0.19(3). In addition, the low temperature anisotropy gap was found to have a slightly higher absolute value under pressure. The consistent values obtained for b in the two systems support the likelihood of a new universality class for triangular, frustrated antiferromagnets

Nanowire Chemical/Biological Sensors: Status and a Roadmap for the Future

Chemiresistive sensors are becoming increasingly important as they offer an inexpensive option to conventional analytical instrumentation, they can be readily integrated into electronic devices, and they have low power requirements. Nanowires (NWs) are a major theme in chemosensor development. High surface area, interwire junctions, and restricted conduction pathways give intrinsically high sensitivity and new mechanisms to transduce the binding or action of analytes. This Review details the status of NW chemosensors with selected examples from the literature. We begin by proposing a principle for understanding electrical transport and transduction mechanisms in NW sensors. Next, we offer the reader a review of device performance parameters. Then, we consider the different NW types followed by a summary of NW assembly and different device platform architectures. Subsequently, we discuss NW functionalization strategies. Finally, we propose future developments in NW sensing to address selectivity, sensor drift, sensitivity, response analysis, and emerging applications

The botanical education extinction and the fall of plant awareness

Civilization is dependent upon plants for survival. Plants permeate our every moment and our relationship with them will dictate how we will manage the threats of climate change and ecological collapse defining the Anthropocene. Yet, despite the significance of plants and the critical role they have played in shaping ecosystems, civilizations, and human cultures, many people are now disconnected from the botanical world. Students are presented with little plant content, particularly identification, compared with animal content. Consequently, we are producing few plant scientists and educating fewer scientists about plants. This drives a self-accelerating cycle we term . A process of knowledge erosion, that in this instance contributes to our separation from the natural world, makes us blind to the biodiversity crisis and inhibits our ability to restore it. We argue that neglecting the importance of plants within education threatens the foundations of industries and professions that rely on this knowledge. Furthermore, this extinction of botanical education creates an existential threat: Without the skills to fully comprehend the scale of and solutions to human-induced global change, how do we as a society combat it? We present key research agendas that will enable us to reverse the extinction of botanical education and highlight the critical role plants play on the global stage