243 research outputs found
Accumulation of Flavonols over Hydroxycinnamic Acids Favors Oxidative Damage Protection under Abiotic Stress
Efficient detoxification of reactive oxygen species (ROS) is thought to play a key role in enhancing the tolerance of plants to abiotic stresses. Although multiple pathways, enzymes, and antioxidants are present in plants, their exact roles during different stress responses remain unclear. Here, we report on the characterization of the different antioxidant mechanisms of tomato plants subjected to heat stress, salinity stress, or a combination of both stresses. All the treatments applied induced an increase of oxidative stress, with the salinity treatment being the most aggressive, resulting in plants with the lowest biomass, and the highest levels of H2O2 accumulation, lipid peroxidation, and protein oxidation. However, the results obtained from the transcript expression study and enzymatic activities related to the ascorbate-glutathione pathway did not fully explain the differences in the oxidative damage observed between salinity and the combination of salinity and heat. An exhaustive metabolomics study revealed the differential accumulation of phenolic compounds depending on the type of abiotic stress applied. An analysis at gene and enzyme levels of the phenylpropanoid metabolism concluded that under conditions where flavonols accumulated to a greater degree as compared to hydroxycinnamic acids, the oxidative damage was lower, highlighting the importance of flavonols as powerful antioxidants, and their role in abiotic stress tolerance.This work was supported by the Ministry of Economy and Competitiveness from Spain (GrantNo. AGL2015-66033-R), and Seneca Foundation from Region of Murcia, Spain (Grant no.15288/ PI/10).Peer reviewedPeer Reviewe
The Miniaturized Moessbauer Spectrometers MIMOS II on MER: Four Years of Operation - A Summary
The two Miniaturized Moessbauer Spectrometers (MIMOS II) on board the two Mars Exploration Rovers Spirit and Opportunity have now been collecting important scientific data for more than four years. The spectrometers provide information about Fe-bearing mineral phases and determine Fe oxidation states. The total amount of targets analized exceeds 600, the total integration time exceeds 260 days for both rovers. Since landing, more than five half-lives of the Co-57 MB sources have past (intensity at the time of landing approx. 150 mCi). Current integration times are about 50 hours in order to achieve reasonable statistics as opposed to 8 hours at the beginning of the mission. In total, 13 different mineral phases were detected: Olivine, pyroxene, hematite, magnetite and nanophase ferric oxide were detected at both landing sites. At Gusev, ilmenite, goethite, a ferric sulfate phase and a yet unassigned phase (in the rock Fuzzy Smith) were detected. At Meridiani, jarosite, metallic iron in meteoritic samples (kamacite), troilite, and an unassigned ferric phase were detected. Jarosite and goethite are of special interest, as these minerals are indicators for water activity. In this abstract, an overview of Moessbauer results will be given, with a focus on data obtained since the last martian winter. The MER mission has proven that Moessbauer spectroscopy is a valuable tool for the in situ exploration of extraterrestrial bodies and for the study of Febearing samples. The experience gained through the MER mission makes MIMOS II a obvious choice for future missions to Mars and other targets. Currently, MIMOS II is on the scientific payload of two approved future missions: Phobos Grunt (Russian Space Agency; 2009) and ExoMars (European Space Agency; 2013)
The PAU survey: classifying low-z SEDs using Machine Learning clustering
This is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The version of record Monthly Notices of the Royal Astronomical Society 524.3 (2023): 3569-3581
is available online at: https://academic.oup.com/mnras/article-abstract/524/3/3569/7225529?redirectedFrom=fulltextWe present an application of unsupervised Machine Learning clustering to the PAU survey of galaxy spectral energy distribution (SED) within the COSMOS field. The clustering algorithm is implemented and optimized to get the relevant groups in the data SEDs. We find 12 groups from a total number of 5234 targets in the survey at 0.01 < z < 0.28. Among the groups, 3545 galaxies (68 per cent) show emission lines in the SEDs. These groups also include 1689 old galaxies with no active star formation. We have fitted the SED to every single galaxy in each group with CIGALE. The mass, age, and specific star formation rates (sSFR) of the galaxies range from 0.15 < age/Gyr <11; 6 < log (M/M⊙) <11.26, and -14.67 < log (sSFR/yr-1) <-8. The groups are well-defined in their properties with galaxies having clear emission lines also having lower mass, are younger and have higher sSFR than those with elliptical like patterns. The characteristic values of galaxies showing clear emission lines are in agreement with the literature for starburst galaxies in COSMOS and GOODS-N fields at low redshift. The star-forming main sequence, sSFR versus stellar mass and UVJ diagram show clearly that different groups fall into different regions with some overlap among groups. Our main result is that the joint of low- resolution (R ∼50) photometric spectra provided by the PAU survey together with the unsupervised classification provides an excellent way to classify galaxies. Moreover, it helps to find and extend the analysis of extreme ELGs to lower masses and lower SFRs in the local UniverseThis work has been supported by the Ministry of Science and Innovation of Spain, project PID2019-107408GB-C43 (ESTALLIDOS), and the Government of the Canary Islands through EU FEDER funding, projects PID2020010050 and PID2021010077. This article is based on observations made in the Observatorios de Canarias of the Instituto de Astrofísica de Canarias (IAC) with the WHT operated on the island of La Palma by the Isaac Newton Group of Telescopes (ING) in the Observatorio del Roque de los Muchachos. The PAU Survey is partially supported by MINECO under grants CSD2007-00060, AYA2015-71825, ESP2017-89838, PGC2018-094773, PGC2018-102021, PID2019-111317GB, SEV-2016-0588, SEV-2016-0597, MDM-2015-0509 and Juan de la Cierva fellowship and LACEGAL and EWC Marie Sklodowska-Curie grant No 734374 and no.776247 with ERDF funds from the EU Horizon 2020 Programme, some of which include ERDF funds from the European Union. IEEC and IFAE are partially funded by the CERCA and Beatriu de Pinos program of the Generalitat de Catalunya. Funding for PAUS has also been provided by Durham Univer sity (via the ERC StG DEGAS-259586), ETH Zurich, Leiden University (via ERC StG ADULT-279396 and Netherlands Organisation for Scientific Research (NWO) Vici grant 639.043.512), University College London and from the European Union’s Horizon 2020 research and innovation programme under the grant agreement No 776247 EWC. The PAU data center is hosted by the Port d’Información Científica (PIC), maintained through a collaboration of CIEMAT and IFAE, with additional support from Universitat Autónoma de Barcelona and ERDF. We acknowledge the PIC services department team for their support and fruitful discussion
The powerful in vitro bioactivity of Euterpe oleracea Mart. seeds and related phenolic compounds
The Euterpe oleracea Mart. (açaí) is a plant from the Amazon region, classified as
"super fruit" because of its various functional properties. However, limited investigation
has been performed on açaí by-products, such as seeds. Therefore, the aim of this work
was to characterized the phenolic compounds of the aqueous extract of açaí seeds and
further evaluate its bioactivity (antioxidant and cytotoxic activities. Only
proanthocyanidins were detected, being a B-type (epi)catechin tetramer the most
abundant; however, procyanidin trimmers were the most predominant form. Açaí seeds
extract revealed a high antioxidant (EC50 ranging from 3.6 to 19.4 μg/mL) and cytotoxic
activity, being more effective in the cervical carcinoma cell line (HeLa; GI50 = 18
μg/mL); it did not show toxicity for non-tumor cells. Açaí seeds are considered a waste
and could have an added economic benefit, through the extraction of natural
antioxidants, particularly proanthocyanidins, that could find applications in food and
pharmaceutical industries.The authors are grateful to Foundation for Science and Technology (FCT, Portugal) for
financial support to the research centre CIMO (strategic project PEst
OE/AGR/UI0690/2011) and L. Barros researcher contract under “Programa
Compromisso com Ciência - 2008”. The authors are also grateful to Jamil S. Oliveira by
the initial discussions on the preparation of samples
Occurrence and levels of polycyclic aromatic hydrocarbons (PAHs) in four fish species from the Bahía Blanca estuary, Argentina
El Estuario de Bahía Blanca permanece bajo una alta y constante presión antrópica; para la evaluación de su impacto dieciseis Hidrocarburos Aromáticos Policíclicos (HAPs) fueron analizados en ejemplares de saraquita (Ramnogaster arcuata), pescadilla de red (Cynoscion guatucupa), corvina rubia (Micropogonias furnieri) y gatuzo (Mustelus schmitti) capturados en muestreos estacionales (2015-2016) en dos sitios del estuario.Considerando todas las especies y clases, la concentración media de la sumatoria de los 16 HAPs (ΣHAPs) fue 35.8 ppb (peso húmedo, n=60, SD= 51.5 ppb), variando de “no detectable” (<0.01 ppb) a 325.17 ppb. En general, las concentraciones de ΣHAPs en todas las especies estudiadas fueron menores a 100 ppb y fueron mayores en los juveniles que en los adultos Saraquita fue la especie que presentó la mayor carga de HAPs. El 5% de las muestras analizadas se hallaron por sobre los niveles de seguridad o screening (USEPA).Centro de Investigaciones Geológica
Occurrence and levels of polycyclic aromatic hydrocarbons (PAHs) in four fish species from the Bahía Blanca estuary, Argentina
El Estuario de Bahía Blanca permanece bajo una alta y constante presión antrópica; para la evaluación de su impacto dieciseis Hidrocarburos Aromáticos Policíclicos (HAPs) fueron analizados en ejemplares de saraquita (Ramnogaster arcuata), pescadilla de red (Cynoscion guatucupa), corvina rubia (Micropogonias furnieri) y gatuzo (Mustelus schmitti) capturados en muestreos estacionales (2015-2016) en dos sitios del estuario.Considerando todas las especies y clases, la concentración media de la sumatoria de los 16 HAPs (ΣHAPs) fue 35.8 ppb (peso húmedo, n=60, SD= 51.5 ppb), variando de “no detectable” (<0.01 ppb) a 325.17 ppb. En general, las concentraciones de ΣHAPs en todas las especies estudiadas fueron menores a 100 ppb y fueron mayores en los juveniles que en los adultos Saraquita fue la especie que presentó la mayor carga de HAPs. El 5% de las muestras analizadas se hallaron por sobre los niveles de seguridad o screening (USEPA).Centro de Investigaciones Geológica
The PAU Survey: a new constraint on galaxy formation models using the observed colour redshift relation
We use the GALFORM semi-analytical galaxy formation model implemented in the
Planck Millennium N-body simulation to build a mock galaxy catalogue on an
observer's past lightcone. The mass resolution of this N-body simulation is
almost an order of magnitude better than in previous simulations used for this
purpose, allowing us to probe fainter galaxies and hence build a more complete
mock catalogue at low redshifts. The high time cadence of the simulation
outputs allows us to make improved calculations of galaxy properties and
positions in the mock. We test the predictions of the mock against the Physics
of the Accelerating Universe Survey, a narrow band imaging survey with highly
accurate and precise photometric redshifts, which probes the galaxy population
over a lookback time of 8 billion years. We compare the model against the
observed number counts, redshift distribution and evolution of the observed
colours and find good agreement; these statistics avoid the need for
model-dependent processing of the observations. The model produces red and blue
populations that have similar median colours to the observations. However, the
bimodality of galaxy colours in the model is stronger than in the observations.
This bimodality is reduced on including a simple model for errors in the
GALFORM photometry. We examine how the model predictions for the observed
galaxy colours change when perturbing key model parameters. This exercise shows
that the median colours and relative abundance of red and blue galaxies provide
constraints on the strength of the feedback driven by supernovae used in the
model
Occurrence and levels of polycyclic aromatic hydrocarbons (PAHs) in four fish species from the Bahía Blanca estuary, Argentina
El Estuario de Bahía Blanca permanece bajo una alta y constante presión antrópica; para la evaluación de su impacto dieciseis Hidrocarburos Aromáticos Policíclicos (HAPs) fueron analizados en ejemplares de saraquita (Ramnogaster arcuata), pescadilla de red (Cynoscion guatucupa), corvina rubia (Micropogonias furnieri) y gatuzo (Mustelus schmitti) capturados en muestreos estacionales (2015-2016) en dos sitios del estuario.Considerando todas las especies y clases, la concentración media de la sumatoria de los 16 HAPs (ΣHAPs) fue 35.8 ppb (peso húmedo, n=60, SD= 51.5 ppb), variando de “no detectable” (<0.01 ppb) a 325.17 ppb. En general, las concentraciones de ΣHAPs en todas las especies estudiadas fueron menores a 100 ppb y fueron mayores en los juveniles que en los adultos Saraquita fue la especie que presentó la mayor carga de HAPs. El 5% de las muestras analizadas se hallaron por sobre los niveles de seguridad o screening (USEPA).Centro de Investigaciones Geológica
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