NEW FINDINGS
What is the central question of this study?
What is the mechanism by which a bout of exercise increases subsequent insulin‐stimulated vasodilatation?
What is the main finding and its ...importance?
Angiotensin‐(1–7) through the Mas receptor participates in enhanced insulin‐induced vasorelaxation after a bout of exercise in healthy rats. This new potential role of angiotensin‐(1–7) could help in understanding how physical activity improves vascular insulin sensitivity in normal and insulin‐resistant states.
Exercise increases insulin‐stimulated vasodilatation, but the mechanisms involved are unclear. This study was performed to investigate the possible involvement of angiotensin‐(1–7) (Ang‐(1–7)), a vasoactive peptide of the renin–angiotensin system (RAS), in enhanced vascular insulin sensitivity after a bout of exercise. Male Wistar rats were subjected to swimming for 2.5 h. After exercise, carbachol‐ or insulin‐induced relaxation in aorta was assessed. Prior exercise improved insulin‐stimulated vasorelaxation; however, this insulin‐sensitizing effect was prevented by the selective Mas receptor (MasR; an Ang‐(1–7) receptor) antagonist A779. Carbachol‐mediated vascular relaxation was not modified by exercise. These results suggest that Ang‐(1–7) acting through MasR participates in the enhancement of vascular insulin sensitivity after an exercise session. This new potential role of Ang‐(1–7) could help in understanding how exercise improves vascular insulin sensitivity in normal and insulin‐resistant states.
A theoretical approach has been developed to study the spin-wave dynamics of magnetization-graded ferromagnetic films, where the magnetic properties change along the film thickness. The theory is ...based on a multilayer approach, where the influence of both long-range dipolar interactions and interlayer exchange coupling between sublayers is included. This allows for instance to describe films with a continuous variation of the saturation magnetization along the thickness. A systematic study is carried out in order to analyze different profiles of the saturation magnetization, which is checked through a test of convergence. It is found that the spin-wave dispersion is significantly modified when the strength of the magnetization changes in the bulk film, where a notable frequency non-reciprocity of two counter propagating spin waves is predicted. This is associated with heterosymmetric mode profiles and a modification of the conventional quantization condition associated to perpendicular standing spin-wave modes. Micromagnetic simulations have been carried out to validate the model, where a perfect agreement is reached between both methods. These results show that magnetization-graded ferromagnetic films can be used to channel and control spin waves, thus promoting different kinds of functionalities for magnon-based devices.
Recombinant Leloir glycosyltransferases can be exploited to synthesize a wide range of HMOs using in vitro biocatalytic reactions. However, high costs and unavailability of bulk amounts of most ...nucleotide sugars, such as guanosine diphosphate L‐fucose (GDP‐Fuc), are major obstacles for the efficient large‐scale synthesis. Here, we report two novel multi‐enzyme cascades for the synthesis of GDP‐Fuc from readily available and low cost precursors. The first cascade was developed to produce GDP‐Fuc from guanosine (Guo), fucose (Fuc), polyphosphate (PolyPn) and catalytic amounts of adenine triphosphate (ATP). GDP‐Fuc was produced with a final concentration of 7 mM (4.1 g/L) and a reaction yield of 68 % from Guo and Fuc within 48 h with a biocatalyst load of 0.34 genzyme/gproduct. A second cascade, consisting of ten enzymes and eleven reactions was developed to carry out the synthesis from mannose (Man), Guo, PolyPn, L‐glutamine (L‐Glu) and catalytic amounts of ATP, and nicotinamide adenine dinucleotide phosphate (NADPH). Utilizing this cascade, GDP‐Fuc was produced with a final concentration of 7.6 mM (4.5 g/L) and a reaction yield of 72 % in a reaction time of 48 h with a biocatalyst load of 0.97 genzyme/gproduct. Finally, a method for chromatographic purification of GDP‐Fuc was established achieving product purities of 90.5 %.
Multi‐enzyme cascade reactions: In vitro enzyme cascades for the one‐pot synthesis of guanosine diphosphate fucose (GDP‐Fuc) from low cost and readily available substrates. In situ co‐factor regeneration was implemented and a robust and scalable ion exchange chromatography protocol for the purification of GDP‐Fuc from the reaction was established. The developed cascades and the purification protocol can be employed for the efficient biocatalytic production of GDP‐Fuc.
Two grain amaranth transcription factor (TF) genes were overexpressed in Arabidopsis plants. The first, coding for a group VII ethylene response factor TF (i.e., AhERF-VII) conferred tolerance to ...water-deficit stress (WS) in transgenic Arabidopsis without affecting vegetative or reproductive growth. A significantly lower water-loss rate in detached leaves coupled to a reduced stomatal opening in leaves of plants subjected to WS was associated with this trait. WS tolerance was also associated with an increased antioxidant enzyme activity and the accumulation of putative stress-related secondary metabolites. However, microarray and GO data did not indicate an obvious correlation between WS tolerance, stomatal closure, and abscisic acid (ABA)-related signaling. This scenario suggested that stomatal closure during WS in these plants involved ABA-independent mechanisms, possibly involving reactive oxygen species (ROS). WS tolerance may have also involved other protective processes, such as those employed for methyl glyoxal detoxification. The second, coding for a class A and cluster I DNA binding with one finger TF (i.e., AhDof-AI) provided salt-stress (SS) tolerance with no evident fitness penalties. The lack of an obvious development-related phenotype contrasted with microarray and GO data showing an enrichment of categories and genes related to developmental processes, particularly flowering. SS tolerance also correlated with increased superoxide dismutase activity but not with augmented stomatal closure. Additionally, microarray and GO data indicated that, contrary to AhERF-VII, SS tolerance conferred by AhDof-AI in Arabidopsis involved ABA-dependent and ABA-independent stress amelioration mechanisms.
Accurate characterization and monitoring of complex subsurface environments require the integration of all the available geophysical, geochemical and geological information. I developed a generalized ...cross‐gradient procedure that seeks multiple geometrically similar images that simplify the integration of cross‐property subsurface information. I jointly invert near‐surface P‐wave, S‐wave, DC resistivity and magnetic data sets recorded at a field site and compound an integrated subsurface (geospectral) image based on the multiple property images found. It is shown that, by analogy to applications in satellite imagery, the geospectral image assembles the multiple subsurface parameter values under a common structural framework that facilitates their visualization and analysis.
The electro-oxidation of carbon materials enormously degrades their performance and limits their wider utilization in multiple electrochemical applications. In this work, the positive influence of ...phosphorus functionalities on the overall electrochemical stability of carbon materials has been demonstrated under different conditions. We show that the extent and selectivity of electroxidation in P-containing carbons are completely different to those observed in conventional carbons without P. The electro-oxidation of P-containing carbons involves the active participation of phosphorus surface groups, which are gradually transformed at high potentials from less-to more-oxidized species to slow down the introduction of oxygen groups on the carbon surface (oxidation) and the subsequent generation of (C*OOH)-like unstable promoters of electro-gasification. The highest-oxidized P groups (–C–O–P-like species) seem to distribute the gained oxygen to neighboring carbon sites, which finally suffer oxidation and/or gasification. So it is thought that P-groups could act as mediators of carbon oxidation although including various steps and intermediates compared to electroxidation in P-free materials.
Grain amaranth is an emerging crop that produces seeds having high quality protein with balanced amino-acid content. However, production is restricted by agronomic limitations that result in yields ...that are lower than those normally produced by cereals. In this work, the use of five different rhizobacteria were explored as a strategy to promote growth and yields in Amaranthus hypochondriacus cv. Nutrisol and A. cruentus cv. Candil, two commercially important grain amaranth cultivars. The plants were grown in a rich substrate, high in organic matter, nitrogen (N), and phosphorus (P) and under greenhouse conditions. Burkholderia ambifaria Mex-5 and B. caribensis XV proved to be the most efficient strains and significantly promoted growth in both grain amaranth species tested. Increased grain yield and harvest index occurred in combination with chemical fertilization when tested in A. cruentus. Growth-promotion and improved yields correlated with increased N content in all tissues examined. Positive effects on growth also occurred in A. cruentus plants grown in a poor soil, even after N and P fertilization. No correlation between non-structural carbohydrate levels in roots of inoculated plants and growth promotion was observed. Conversely, gene expression assays performed at 3-, 5- and 7-weeks after seed inoculation in plants inoculated with B. caribensis XV identified a tissue-specific induction of several genes involved in photosynthesis, sugar- and N- metabolism and transport. It is concluded that strains of Burkholderia effectively promote growth and increase seed yields in grain amaranth. Growth promotion was particularly noticeable in plants grown in an infertile soil but also occurred in a well fertilized rich substrate. The positive effects observed may be attributed to a bio-fertilization effect that led to increased N levels in roots and shoots. The latter effect correlated with the differential induction of several genes involved in carbon and N metabolism and transport.
Abstract
The magnonic band structure of two-dimensional chiral magnonic crystals is theoretically investigated. The proposed metamaterial involves a three-dimensional architecture, where a thin ...ferromagnetic layer is in contact with a two-dimensional periodic array of heavy-metal square islands. When these two materials are in contact, an anti-symmetric exchange coupling known as the Dzyaloshinskii–Moriya interaction (DMI) arises, which generates nonreciprocal spin waves and chiral magnetic order. The Landau–Lifshitz equation and the plane-wave method are employed to study the dynamic magnetic behavior. A systematic variation of geometric parameters, the DMI constant, and the filling fraction allows the examination of spin-wave propagation features, such as the spatial profiles of the dynamic magnetization, the isofrequency contours, and group velocities. In this study, it is found that omnidirectional flat magnonic bands are induced by a sufficiently strong Dzyaloshinskii–Moriya interaction underneath the heavy-metal islands, where the spin excitations are active. The theoretical results were substantiated by micromagnetic simulations. These findings are relevant for envisioning applications associated with spin-wave-based logic devices, where the nonreciprocity and channeling of the spin waves are of fundamental and practical scientific interest.
The Humboldt Sulfuretum (HS), in the productive Humboldt Eastern Boundary Current Upwelling Ecosystem, extends under the hypoxic waters of the Peru-Chile Undercurrent (ca. 6°S and ca. 36°S). Studies ...show that primeval sulfuretums held diverse prokaryotic life, and, while rare today, still sustain species-rich giant sulfur-oxidizing bacterial communities. We here present the genomic features of a new bacteria of the HS, "Candidatus Venteria ishoeyi" ("Ca. V. ishoeyi") in the family Thiotrichaceae.Three identical filaments were micro-manipulated from reduced sediments collected off central Chile; their DNA was extracted, amplified, and sequenced by a Roche 454 GS FLX platform. Using three sequenced libraries and through de novo genome assembly, a draft genome of 5.7 Mbp, 495 scaffolds, and a N50 of 70 kbp, was obtained. The 16S rRNA gene phylogenetic analysis showed that "Ca. V. ishoeyi" is related to non-vacuolate forms presently known as Beggiatoa or Beggiatoa-like forms. The complete set of genes involved in respiratory nitrate-reduction to dinitrogen was identified in "Ca. V. ishoeyi"; including genes likely leading to ammonification. As expected, the sulfur-oxidation pathway reported for other sulfur-oxidizing bacteria were deduced and also, key inorganic and organic carbon acquisition related genes were identified. Unexpectedly, the genome of "Ca. V. ishoeyi" contained numerous CRISPR repeats and an I-F CRISPR-Cas type system gene coding array. Findings further show that, as a member of an eons-old marine ecosystem, "Ca. V. ishoeyi" contains the needed metabolic plasticity for life in an increasingly oxygenated and variable ocean.
Vaccination is a widely used control strategy to prevent Piscirickettsia salmonis causing disease in salmon farming. However, it is not known why all the currently available commercial vaccines ...generally fail to protect against this pathogenic bacteria. Here, we report, from two different populations, that between-family variation is a strong intrinsic factor that determines vaccine protection for this disease. While in some full-sib families, the protection added by vaccination increased the survival time in 13 days in comparison with their unvaccinated siblings; in other families, there was no added protection by vaccination or even it was slightly negative. Resistance to P. salmonis, measured as days to death, was higher in vaccinated than unvaccinated fish, but only a moderate positive genetic correlation was obtained between these traits. This disputes a previous hypothesis, that stated that both traits were fully controlled by the same genes, and challenges the use of unvaccinated fish as gold standard for evaluating and selecting fish resistant to P. salmonis, particularly if the offspring will be vaccinated. More studies are necessary to evaluate if variation in the host immune response to vaccination could explain the between-family differences in resistance observed in vaccinated fish.
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