Acumulación estacional de una deshidrina de 47-kDa en hojas y cambios en su actividad crioprotectora en Nothofagus dombeyi (Mirb.) Blume

Nothofagus dombeyi (Mirb.) Blume is an evergreen tree, pioneer in habitats subject to unfavorable environmental conditionsas nighttime freezing temperatures and low water content. It inhabits zones characterized by cold Winter with freezingtemperature and Spring frosts reaching to -5ºC. Furthermore, it has the capacity to maintain a functional photosyntheticapparatus at low temperatures. We postulated that N. dombeyi is capable to accumulate dehydrins in leaves in response tocold. Seasonal variation in dehydrins, soluble total proteins, and cryoprotective activity in vitro of protein extracts of N.dombeyi leaves were analyzed during the years 2004 and 2005. A dehydrin-like protein of 47-kDa was immunologicallyidentified; this protein was present only in Winter and Spring. The highest accumulation of this protein and the maximalin vitro cryoprotective activity was found during Spring. The leaf total protein extract of this season preserved the 100%of lactate dehydrogenase (LDH) enzyme activity after 5 freeze/thaw cycles in liquid nitrogen adding 10 ?g/ml of totalproteins extract. The soluble protein concentration increased from 1.8 mg/g in Summer to 4.8 mg/g in Fall on base offresh weight, and declined through Winter and Spring. The 47-kDa dehydrin may be related to cold hardiness of leaftissue in overwintering N. dombeyi. We conclude that cell dehydration caused by freezing is the main factor involved inthe triggering of 47-kDa dehydrin accumulation in leaves of N. dombeyi. The accumulation of reactive oxygen species(ROS) by oxidative stress product of high irradiance and frosts during Spring, and their role in the triggering of the 47-kDadehydrin accumulation in leaves of N. dombeyi is discussed.Nothofagus dombeyi (Mirb.) Blume es un árbol siempreverde, pionero en sitios con condiciones ambientales desfavorablescomo baja temperatura nocturna y baja disponibilidad hídrica. Habita en zonas caracterizadas por inviernos fríos contemperaturas congelantes y heladas de primavera que pueden llegar a los -5ºC. Además tiene la capacidad de mantenersu aparato fotosintético funcional en condiciones de baja temperatura. Postulamos que N. dombeyi es capaz de acumulardeshidrinas en sus hojas en respuesta a baja temperatura. Se analizó la variación estacional de deshidrinas, proteínas solublestotales y la actividad crioprotectora in vitro de extractos proteicos de hojas de N. dombeyi durante los años 2004 y 2005. Unaproteína con características de deshidrina de 47 kDa de peso molecular fue identificada inmunológicamente en hojas, la queestuvo presente sólo en invierno y primavera. La mayor acumulación de esta proteína en las hoja y la máxima crioprotecciónin vitro fue encontrada durante la estación de primavera. El extracto total de proteínas de esta estación conservó el 100% dela actividad de la enzima lactato deshidrogenasa (LDH) después de 5 ciclos de congelamiento/descongelamiento en nitrógenolíquido agregando 10 ?g/ml de extracto total de proteínas. La concentración de proteínas solubles totales aumentó de 1,8 mgpor gramo de peso fresco en verano a 4,8 mg en otoño, y disminuyó durante el invierno y la primavera. La deshidrina de 47kDa podría estar relacionada al endurecimiento por frío del tejido foliar en individuos de N. dombeyi durante el invierno,aumentando su resistencia al congelamiento. Concluimos que la deshidratación celular producida por congelamiento sería elprincipal factor en estimular la acumulación de esta deshidrina de 47kDa en hojas de N. dombeyi. La acumulación de especiesreactivas de oxígeno (ROS) por estrés oxidativo producto de la alta irradiancia y heladas durante la primavera y su papel en elgatillamiento de la acumulación de esta deshidrina de 47 kDa en las hojas es discutida

Biological interactions and simulated climate change modulates the ecophysiological performance of Colobanthus quitensis in the Antarctic ecosystem

Most climate and environmental change models predict significant increases in temperature and precipitation by the end of the 21st Century, for which the current functional output of certain symbioses may also be altered. In this context we address the following questions: 1) How the expected changes in abiotic factors (temperature, and water) differentially affect the ecophysiological performance of the plant Colobanthus quitensis? and 2) Will this environmental change indirectly affect C. quitensis photochemical performance and biomass accumulation by modifying its association with fungal endophytes? Plants of C. quitensis from King George Island in the South Shetland archipelago (62°09′ S), and Lagotellerie Island in the Antarctic Peninsula (65°53′ S) were put under simulated abiotic conditions in growth chambers following predictive models of global climate change (GCC). The indirect effect of GCC on the interaction between C. quitensis and fungal endophytes was assessed in a field experiment carried out in the Antarctica, in which we eliminated endophytes under contemporary conditions and applied experimental watering to simulate increased precipitation input. We measured four proxies of plant performance. First, we found that warming (+W) significantly increased plant performance, however its effect tended to be less than watering (+W) and combined warming and watering (+T°+W). Second, the presence of fungal endophytes improved plant performance, and its effect was significantly decreased under experimental watering. Our results indicate that both biotic and abiotic factors affect ecophysiological performance, and the directions of these influences will change with climate change. Our findings provide valuable information that will help to predict future population spread and evolution through using ecological niche models under different climatic scenarios

A pharmacogenetic pilot study reveals MTHFR, DRD3, and MDR1 polymorphisms as biomarker candidates for slow atorvastatin metabolizers

Background: The genetic variation underlying atorvastatin (ATV) pharmacokinetics was evaluated in a Mexican population. Aims of this study were: 1) to reveal the frequency of 87 polymorphisms in 36 genes related to drug metabolism in healthy Mexican volunteers, 2) to evaluate the impact of these polymorphisms on ATV pharmacokinetics, 3) to classify the ATV metabolic phenotypes of healthy volunteers, and 4) to investigate a possible association between genotypes and metabolizer phenotypes. Methods: A pharmacokinetic study of ATV (single 80-mg dose) was conducted in 60 healthy male volunteers. ATV plasma concentrations were measured by high-performance liquid chromatography mass spectrometry. Pharmacokinetic parameters were calculated by the non-compartmental method. The polymorphisms were determined with the PHARMAchip® microarray and the TaqMan® probes genotyping assay. Results: Three metabolic phenotypes were found in our population: slow, normal, and rapid. Six gene polymorphisms were found to have a significant effect on ATV pharmacokinetics: MTHFR (rs1801133), DRD3 (rs6280), GSTM3 (rs1799735), TNFα (rs1800629), MDR1 (rs1045642), and SLCO1B1 (rs4149056). The combination of MTHFR, DRD3 and MDR1 polymorphisms associated with a slow ATV metabolizer phenotype. Conclusion: Further studies using a genetic preselection method and a larger population are needed to confirm these polymorphisms as predictive biomarkers for ATV slow metabolizers

Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

This paper presents measurements of the $W^+ \rightarrow \mu^+\nu$ and $W^- \rightarrow \mu^-\nu$ cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector

A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13  TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139  fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV

Searches for lepton-flavour-violating decays of the Higgs boson in s=13\sqrt{s}=13 TeV pp\mathit{pp} collisions with the ATLAS detector

This Letter presents direct searches for lepton flavour violation in Higgs boson decays, H → eτ and H → μτ , performed with the ATLAS detector at the LHC. The searches are based on a data sample of proton–proton collisions at a centre-of-mass energy √s = 13 TeV, corresponding to an integrated luminosity of 36.1 fb−1. No significant excess is observed above the expected background from Standard Model processes. The observed (median expected) 95% confidence-level upper limits on the leptonflavour-violating branching ratios are 0.47% (0.34+0.13−0.10%) and 0.28% (0.37+0.14−0.10%) for H → eτ and H → μτ , respectively.publishedVersio

Search for heavy neutral Higgs bosons produced in association with b-quarks and decaying into b-quarks at root s=13 TeV with the ATLAS detector

A search for heavy neutral Higgs bosons produced in association with one or two b -quarks and decaying to b -quark pairs is presented using 27.8  fb − 1 of √ s = 13  TeV proton-proton collision data recorded by the ATLAS detector at the Large Hadron Collider during 2015 and 2016. No evidence of a signal is found. Upper limits on the heavy neutral Higgs boson production cross section times its branching ratio to b ¯ b are set, ranging from 4.0 to 0.6 pb at 95% confidence level over a Higgs boson mass range of 450 to 1400 GeV. Results are interpreted within the two-Higgs-doublet model and the minimal supersymmetric Standard Model

Combination of searches for Higgs boson pairs in pp collisions at \sqrts = 13 TeV with the ATLAS detector

This letter presents a combination of searches for Higgs boson pair production using up to 36.1 fb(-1) of proton-proton collision data at a centre-of-mass energy root s = 13 TeV recorded with the ATLAS detector at the LHC. The combination is performed using six analyses searching for Higgs boson pairs decaying into the b (b) over barb (b) over bar, b (b) over barW(+)W(-), b (b) over bar tau(+)tau(-), W+W-W+W-, b (b) over bar gamma gamma and W+W-gamma gamma final states. Results are presented for non-resonant and resonant Higgs boson pair production modes. No statistically significant excess in data above the Standard Model predictions is found. The combined observed (expected) limit at 95% confidence level on the non-resonant Higgs boson pair production cross-section is 6.9 (10) times the predicted Standard Model cross-section. Limits are also set on the ratio (kappa(lambda)) of the Higgs boson self-coupling to its Standard Model value. This ratio is constrained at 95% confidence level in observation (expectation) to -5.0 &lt; kappa(lambda) &lt; 12.0 (-5.8 &lt; kappa(lambda) &lt; 12.0). In addition, limits are set on the production of narrow scalar resonances and spin-2 Kaluza-Klein Randall-Sundrum gravitons. Exclusion regions are also provided in the parameter space of the habemus Minimal Supersymmetric Standard Model and the Electroweak Singlet Model. For complete list of authors see http://dx.doi.org/10.1016/j.physletb.2019.135103</p