1,899 research outputs found
Zn2+-Dependent Histone Deacetylases in Plants: Structure and Evolution
Zn2+-dependent histone deacetylases are widely distributed in archaea, bacteria, and eukaryotes. Through deacetylation of histones and other biomolecules, these enzymes regulate mammalian gene expression, microtubule stability, and polyamine metabolism. In plants, they play essential roles in development and stress response, but little is known about their biochemistry. We provide here a holistic revision of plant histone deacetylase (HDA) phylogeny and translate recent lessons from other organisms. HDA evolution correlates with a gain of structural ductility/disorder, as observed for other proteins. We also highlight two recently identified Brassicaceae-specific HDAs, as well as unprecedented key mutations that would affect the catalytic activity of individual HDAs. This revised phylogeny will contextualize future studies and illuminate research on plant development and adaptation
Turnover and stability in the deep sea: Benthic foraminifera as tracers of Paleogene global change
Benthic foraminifera are the most common meiofaunal unicellular deep-sea biota, forming skeletons used as proxies for past climate change. We aim to increase understanding of past non-analog oceans and ecosystems by evaluating deep-sea benthic foraminiferal responses to global environmental changes over latest Cretaceous through Oligocene times (67–23 million years ago). Earth suffered an asteroid impact at the end of the Cretaceous (~instantaneous; 66 Ma), episodes of rapid global warming during the Paleocene-Eocene Thermal Maximum (PETM; ~56 Ma) and other hyperthermals (millennial timescales), followed by gradual, but punctuated cooling (timescales of hundred thousands of years) from a world without polar ice sheets to a world with a large Antarctic ice sheet. Here we present the first compilation of quantitative data on deep-sea foraminifera at sites in all the world''s oceans, aiming to build a first unique, uniform database that allows comparison of deep-sea faunal turnover across the uppermost Cretaceous through Paleogene. We document variability in space and time of benthic foraminiferal diversity: lack of extinction at the asteroid impact even though other marine and terrestrial groups suffered mass extinction; major extinction at the PETM followed by recovery and diversification; and gradual but fundamental turnover during gradual cooling and increase in polar ice volume (possibly linked to changes in the oceanic carbon cycle). High latitude cooling from ~45 Ma on, i.e., after the end of the Early Eocene Climate Optimum (53.2–49.2 Ma), may have made the middle Eocene a critical period of several millions of years of faunal turnover and establishment of latitudinal diversity gradients. This compilation thus illuminates the penetration of global change at very different rates into the largest and one of the most stable habitats on Earth, the deep sea with its highly diverse biota
Updating a Paleogene magnetobiochronological time scale through graphical integration
All studies focused on the evaluation of paleoecological variability over geological time must be linked to a specific age or time interval, which can be defined using different time scales (biostratigraphic, chronostratigraphic, geochronological or orbital). Therefore, integrated time scales are essential to allow comparisons of data from different locations and/or to assess evolutionary and other events through time. Here we use a new method to update a Paleogene magnetobiochronological time scale, with the following contributions: • The update of the Paleogene magnetobiochronological scale was made by graphical correlation with new age models and adding calcareous nannoplankton and planktonic foraminiferal biozones from different authors. • An excel file structure was proposed to plot any kind of data in MATLAB software, as long as they are associated with some of the scales shown in our updated version of Paleogene magnetobiochronology. • The excel file structure facilitates the analysis of long-term trends of taxonomic groups throughout the Paleogene, and of their evolution in a period characterized by intense climate variability
Airy processes and variational problems
We review the Airy processes; their formulation and how they are conjectured
to govern the large time, large distance spatial fluctuations of one
dimensional random growth models. We also describe formulas which express the
probabilities that they lie below a given curve as Fredholm determinants of
certain boundary value operators, and the several applications of these
formulas to variational problems involving Airy processes that arise in
physical problems, as well as to their local behaviour.Comment: Minor corrections. 41 pages, 4 figures. To appear as chapter in "PASI
Proceedings: Topics in percolative and disordered systems
Welfare of horses from Mexico and the United States of America transported for slaughter in Mexico: Fitness profiles for transport and pre-slaughter logistics
Every year thousands of horses from Mexico and the United States of America (USA) are transported to slaughter in Mexico, but little is known about their welfare or pre-slaughter logistics. In this study, we recorded the origin, sex, age and condition of horses (121 journeys, 2648 animals) upon arrival to an abattoir in northern Mexico, including transport details. Horse welfare was measured indirectly via individual scores for body condition, coat quality, lameness, ocular and nasal discharge, as well as reactivity to a chute restraint test, all performed shortly after unloading. The average journey duration was 9.69 (±7.6) hours for horses from Mexico and 16.77 (±4.51) hours for horses from the USA (77 % of all journeys). The prevalence of ocular discharge, nasal discharge, skin wounds, lameness and diarrhoea, were 23 %, 12 %, 11 %, 9 %, 1 % (respectively) of all the horses observed, with no significant differences between Mexican and American horses (P = 0.05). During the chute test the American horses were calmer than the Mexican ones (P < 0.001), who were more restless and aggressive (P = 0.001). Likewise, vocalizations in their three variants during the restraint, neigh/whinny (P = 0.018), nicker (P < 0.001), and snort (P = 0.018), were more common in horses from Mexico. In order to help characterize fitness for transport, a two-step cluster analysis was applied using the welfare indicators, suggesting the existence of four clusters (C) evaluated on arrival at the abattoir (from good to very poor fitness): good (profile C4, n = 769, 29.1 %), average (profile C1, n = 799 horses, 30.2 %), poor (profile C3, n = 586, 22.1 %) and very poor (profile C2, n = 494, 18.6 %). In fact, the C4 best welfare group had 0% lame, 0% nasal discharge, 16.4 % ocular discharge, 7.9 % skin wounds. Instead, the C2 poorest welfare group had 45.8 % lame, 61.1 % nasal discharge, 42.8 % ocular discharge, and 19.9 % skin wounds. Results show potential for using nasal discharge, lameness and ocular discharge as key indicators of horse fitness and welfare on abattoir. The study provides detailed scientific data to help establish strategies regarding optimal days of recovery post-transport and fattening for homogenization of weights between animals of different origins, logistic planning, and optimization of logistic resources to minimize the biological cost of long-distance transport
Understanding mountain soils : a contribution from mountain areas to the International Year of Soils 2015
A volcanic tuff rock known as cangahua (Ecuador) or tepetate (Mexico) is found throughout the Andes. Problems have arisen as the layers of light but fragile soil that once covered the tuff have been lost for both natural (environmental) reasons and because of over-cultivation. When the soil is gone, the tuff is impermeable and sterile. Now, a project in Ecuador has determined that the tuff itself can be reclaimed and is supporting a programme that sends bulldozers to the tuff regions to break up the rock and create a new fertile soil
The Medical Oncology resident mentor: situation and workload
Purpose: The Spanish Society for Medical Oncology (SEOM, for its acronym in Spanish) and the National Commission for the Specialty of Medical Oncology seek to highlight the important workload and unrecognized dedication entailed in working as a Medical Oncology (MO) resident mentor, as well as its relevance for the quality of teaching units and the future of the specialty.
Materials and methods: The current situation and opinion regarding the activity of MO resident mentors was analyzed by reviewing the standing national and autonomic community regulations and via an online survey targeting mentors, residents, and physicians who are not MO mentors. The project was supervised by a specially designated group that agreed on a proposal containing recommendations for improvement.
Results: Of the MO mentors, 90% stated that they did not have enough time to perform their mentoring duties. An estimated 172 h/year on average was dedicated to mentoring, which represents 10.1% of the total time. MO mentors dedicate an average of 6.9 h/month to these duties outside their workday. Forty-five percent of the mentors feel that their role is scantly recognized, if at all.
Conclusions: The study reveals the substantial dedication and growing complexity of MO resident mentoring. A series of recommendations are issued to improve the conditions in which it is carried out, including the design of systems that adapt to the professional activity in those departments that have time set aside for mentoring tasks
FTIR-ATR Spectroscopy Combined with Multivariate Regression Modeling as a Preliminary Approach for Carotenoids Determination in Cucurbita spp
Quantitative analysis of carotenoids has been extensively reported using UV\u2010Vis
spectrophotometry and chromatography, instrumental techniques that require complex extraction
protocols with organic solvents. Fourier transform infrared spectroscopy (FTIR) is a potential
alternative for simplifying the analysis of food constituents. In this work, the application of FTIR
with attenuated total reflectance (ATR) was evaluated for the determination of total carotenoid
content (TCC) in Cucurbita spp. samples. Sixty\u2010three samples, belonging to different cultivars of
butternut squash (C. moschata) and pumpkin (C. maxima), were selected and analyzed with
FTIR\u2010 ATR (attenuated total reflectance). Three different preparation protocols for samples were
followed: homogenization (A), freeze\u2010drying (B), and solvent extraction (C). The recorded spectra
were used to develop regression models by Partial Least Squares (PLS), using data from TCC,
determined by UV\u2010Vis spectrophotometry. The PLS regression model obtained with the FTIR data
from the freeze\u2010dried samples, using the spectral range 920\u20133000 cm 121, had the best figures of merit
(R2CAL of 0.95, R2PRED of 0.93 and RPD of 3.78), being reliable for future application in agriculture. This
approach for carotenoid determination in pumpkin and squash avoids the use of organic solvents.
Moreover, these results are a rationale for further exploring this technique for the assessment of
specific carotenoids in food matrices
Constituents of Quercus eduardii leaf infusion: Their interaction with gut microbiota communities and therapeutic role in colorectal cancer.
The infusion of Q. eduardii leaves has been used ancestrally for medicinal purposes. We investigated the effect of
Q. eduardii infusion intake on inflammatory and oncogenic biomarkers in animals induced to have colorectal
cancer with DMH. We also investigated its influence on the microbiota, establishing the main microbial metabolites
in the intestinal content of the experimental animals. The microbial metabolites associated with greater
anti-inflammatory and anticarcinogenic activity were 3́-hydroxyphenylacetic acid (3HPA) and €-3-(3,4,5-trimethoxyphenyl)
prop-2-enoic acid (TMCA). Finally, the intake of the Q. eduardii infusion significantly increased
the abundance of the Erysipelotrichaceae and Lachnospiraceae families, that seems to have a great influence on the
antitumor responses detected in the study.post-print4648 K
Potencial Analítico de los Polímeros de Impronta Molecular (MIPs) como Elementos de Reconocimiento Biomimético
Los polímeros de impronta molecular (MIPs) son materiales sintéticos que presentan propiedades de reconocimiento molecular específico hacia determinados compuestos. Estos materiales con “memoria selectiva” presentan un elevado potencial analítico como sustitutos de elementos de reconocimiento de origen biológico para el desarrollo de sensores, como sorbentes en procesos de extracción en fase sólida (SPE) y como fases estacionarias para HPLC y CE. La síntesis de estos materiales se basa en la formación de una estructura polimérica, altamente entrecruzada, alrededor de una molécula que actúa como plantilla que se extrae después de la polimerización. De esta forma, el MIP contendrá sitios de unión que son complementarios a la molécula plantilla en forma, tamaño y distribución de grupos funcionales que permiten su reconocimiento posterior, de forma selectiva Los MIPs suelen presentar ventajas interesantes en comparación con los receptore
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