982 research outputs found
Particle size distribution and mineralogy of Brazilian Ferralsols: Significance for the structure and hydraulic properties.
The Cerrados Biome is one of the major regions of Brazil with 24% of the Brazilian territory (204.106 ha). It is mainly located in the center of Brazil and corresponds to the whole Central Plateau. About 49% of the soils are Ferralsols and approximately 79.106 ha of these soils are dedicated to agriculture. The main characteristics of Ferralsols are a poor horizonation, a weak development of the macrostructure, and a strong submillimetric granular microstructure
Role of rhizospheric microbiota as a bioremediation tool for the protection of soil-plant systems from microcystins phytotoxicity and mitigating toxin-related health risk
Frequent toxic cyanoblooms in eutrophic freshwaters produce various cyanotoxins such as the monocyclic heptapeptides microcystins (MCs), known as deleterious compounds to plant growth and human health. Recently, MCs are a recurrent worldwide sanitary problem in irrigation waters and farmland soils due to their transfer and accumulation in the edible tissues of vegetable produce. In such cases, studies about the persistence and removal of MCs in soil are scarce and not fully investigated. In this study, we carried out a greenhouse trial on two crop species: faba bean (Vicia faba var. Alfia 321) and common wheat (Triticum aestivum var. Achtar) that were grown in sterile (microorganism-free soil) and non-sterile (microorganism-rich soil) soils and subjected to MC-induced stress at 100 µg equivalent MC-LR L−1. The experimentation aimed to assess the prominent role of native rhizospheric microbiota in mitigating the phytotoxic impact of MCs on plant growth and reducing their accumulation in both soils and plant tissues. Moreover, we attempted to evaluate the health risk related to the consumption of MC-polluted plants for humans and cattle by determining the estimated daily intake (EDI) and health risk quotient (RQ) of MCs in these plants. Biodegradation was liable to be the main removal pathway of the toxin in the soil; and therefore, bulk soil (unplanted soil), as well as rhizospheric soil (planted soil), were used in this experiment to evaluate the accumulation of MCs in the presence and absence of microorganisms (sterile and non-sterile soils). The data obtained in this study showed that MCs had no significant effects on growth indicators of faba bean and common wheat plants in non-sterile soil as compared to the control group. In contrast, plants grown in sterile soil showed a significant decrease in growth parameters as compared to the control. These results suggest that MCs were highly bioavailable to the plants, resulting in severe growth impairments in the absence of native rhizospheric microbiota. Likewise, MCs were more accumulated in sterile soil and more bioconcentrated in root and shoot tissues of plants grown within when compared to non-sterile soil. Thereby, the EDI of MCs in plants grown in sterile soil was more beyond the tolerable daily intake recommended for both humans and cattle. The risk level was more pronounced in plants from the sterile soil than those from the non-sterile one. These findings suggest that microbial activity, eventually MC-biodegradation, is a crucial bioremediation tool to remove and prevent MCs from entering the agricultural food chain. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.This project has received funding from the European Union?s Horizon 2020 research and innovation program under the Marie Sk?odowska-Curie grant agreement No. 823860 and co-sup-ported by the strategical funding from FCT UIDB/04423/2020 and UIDP/04423/2020
Geodesic distance for right invariant Sobolev metrics of fractional order on the diffeomorphism group
We study Sobolev-type metrics of fractional order on the group
\Diff_c(M) of compactly supported diffeomorphisms of a manifold . We show
that for the important special case the geodesic distance on
\Diff_c(S^1) vanishes if and only if . For other manifolds we
obtain a partial characterization: the geodesic distance on \Diff_c(M)
vanishes for and for ,
with being a compact Riemannian manifold. On the other hand the geodesic
distance on \Diff_c(M) is positive for and
.
For we discuss the geodesic equations for these metrics. For
we obtain some well known PDEs of hydrodynamics: Burgers' equation for ,
the modified Constantin-Lax-Majda equation for and the
Camassa-Holm equation for .Comment: 16 pages. Final versio
Biochemical and colour changes of watercress (Nasturtium officinale R. Br.) during freezing and frozen storage
The effects of water blanching, freezing, and frozen storage during 400 days at three different temperatures (-7, - 15 and -30 degrees C), on watercress (Nasturtium officinale R. Br.) colour Hunter Lab parameters, chlorophyll degradation, vitamin C content loss and peroxidase (POD) activity were evaluated. The blanching induced significant changes on colour values and chlorophylls and vitamin C contents. POD activity was reduced 85% from its initial value. Freezing did not affect chlorophylls and vitamin C levels, however, promoted significant differences in colour values and POD residual activity. During frozen storage, ascorbic acid (AA) and POD activity degradations followed first-order kinetics, and colour parameters (L(H) . a(H) . b(H), -a(H)/b(H,) L(H) . a(H)/b(H), L(H)/a(H) and hue (h(H)(0))) were Successfully described by zero-order kinetics. The Storage temperature effect Was Successfully described by the Arrhenius law. Chlorophylls and dehydroascorbic acid (DHAA) contents were kept constant during frozen storage. (C) 2008 Elsevier Ltd. All rights reserved
PINK1 cleavage at position A103 by the mitochondrial protease PARL
Mutations in PTEN-induced kinase 1 (PINK1) cause early onset autosomal recessive Parkinson's disease (PD). PINK1 is a 63 kDa protein kinase, which exerts a neuroprotective function and is known to localize to mitochondria. Upon entry into the organelle, PINK1 is cleaved to produce a ∼53 kDa protein (ΔN-PINK1). In this paper, we show that PINK1 is cleaved between amino acids Ala-103 and Phe-104 to generate ΔN-PINK1. We demonstrate that a reduced ability to cleave PINK1, and the consequent accumulation of full-length protein, results in mitochondrial abnormalities reminiscent of those observed in PINK1 knockout cells, including disruption of the mitochondrial network and a reduction in mitochondrial mass. Notably, we assessed three N-terminal PD-associated PINK1 mutations located close to the cleavage site and, while these do not prevent PINK1 cleavage, they alter the ratio of full-length to ΔN-PINK1 protein in cells, resulting in an altered mitochondrial phenotype. Finally, we show that PINK1 interacts with the mitochondrial protease presenilin-associated rhomboid-like protein (PARL) and that loss of PARL results in aberrant PINK1 cleavage in mammalian cells. These combined results suggest that PINK1 cleavage is important for basal mitochondrial health and that PARL cleaves PINK1 to produce the ΔN-PINK1 fragment
Plant-derived bioactives and oxidative stress-related disorders: A key trend towards healthy aging and longevity promotion
Plants and their corresponding botanical preparations have been used for centuries due to their remarkable potential in both the treatment and prevention of oxidative stress-related disorders. Aging and aging-related diseases, like cardiovascular disease, cancer, diabetes, and neurodegenerative disorders, which have increased exponentially, are intrinsically related with redox imbalance and oxidative stress. Hundreds of biologically active constituents are present in each whole plant matrix, providing promissory bioactive effects for human beings. Indeed, the worldwide population has devoted increased attention and preference for the use of medicinal plants for healthy aging and longevity promotion. In fact, plant-derived bioactives present a broad spectrum of biological effects, and their antioxidant, anti-inflammatory, and, more recently, anti-aging effects, are considered to be a hot topic among the medical and scientific communities. Nonetheless, despite the numerous biological effects, it should not be forgotten that some bioactive molecules are prone to oxidation and can even exert pro-oxidant effects. In this sense, the objective of the present review is to provide a detailed overview of plant-derived bioactives in age-related disorders. Specifically, the role of phytochemicals as antioxidants and pro-oxidant agents is carefully addressed, as is their therapeutic relevance in longevity, aging-related disorders, and healthy-aging promotion. Finally, an eye-opening look into the overall evidence of plant compounds related to longevity is present
Variability in ecosystem service measurement: A pollination service case study
Research quantifying ecosystem services (ES) - collectively, the benefits that society obtains from ecosystems - is rapidly increasing. Despite the seemingly straightforward definition, a wide variety of methods are used to measure ES. This methodological variability has largely been ignored, and standard protocols to select measures that capture ES provision have yet to be established. Furthermore, most published papers do not include explicit definitions of individual ES. We surveyed the literature on pollination ES to assess the range of measurement approaches, focusing on three essential steps: (1) definition of the ES, (2) identification of components contributing to ES delivery, and (3) selection of metrics to represent these components. We found considerable variation in how pollination as an ES - a relatively well-defined service - is measured. We discuss potential causes of this variability and provide suggestions to address this issue. Consistency in ES measurement, or a clear explanation of selected definitions and metrics, is critical to facilitate comparisons among studies and inform ecosystem management
Fitting the integrated Spectral Energy Distributions of Galaxies
Fitting the spectral energy distributions (SEDs) of galaxies is an almost
universally used technique that has matured significantly in the last decade.
Model predictions and fitting procedures have improved significantly over this
time, attempting to keep up with the vastly increased volume and quality of
available data. We review here the field of SED fitting, describing the
modelling of ultraviolet to infrared galaxy SEDs, the creation of
multiwavelength data sets, and the methods used to fit model SEDs to observed
galaxy data sets. We touch upon the achievements and challenges in the major
ingredients of SED fitting, with a special emphasis on describing the interplay
between the quality of the available data, the quality of the available models,
and the best fitting technique to use in order to obtain a realistic
measurement as well as realistic uncertainties. We conclude that SED fitting
can be used effectively to derive a range of physical properties of galaxies,
such as redshift, stellar masses, star formation rates, dust masses, and
metallicities, with care taken not to over-interpret the available data. Yet
there still exist many issues such as estimating the age of the oldest stars in
a galaxy, finer details ofdust properties and dust-star geometry, and the
influences of poorly understood, luminous stellar types and phases. The
challenge for the coming years will be to improve both the models and the
observational data sets to resolve these uncertainties. The present review will
be made available on an interactive, moderated web page (sedfitting.org), where
the community can access and change the text. The intention is to expand the
text and keep it up to date over the coming years.Comment: 54 pages, 26 figures, Accepted for publication in Astrophysics &
Space Scienc
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