3,011 research outputs found
Genetic analysis and management in small populations: the Asturcon pony as an example
International audienc
Alien species in the Guadiana Estuary (SE-Portugal/SW-Spain): Blackfordia virginica (Cnidaria, Hydrozoa) and Palaemon macrodactylus (Crustacea, Decapoda): potential impacts and mitigation measures
The cnidarian Blackfordia virginica and the adult of the caridean prawn, Palaemon macrodactylus are first recorded from the
Guadiana Estuary. The habitats and environmental conditions under which these species were found are described and the
potential impacts and mitigation measures for their introduction are discussed. The first observations of adults of these species
were made in July 2008, at the transitional zone of the estuary (brackish area). Most samples taken in the middle-estuary were
characterized by large densities of B. virginica (> 100 individuals 100 m-3), while P. macrodactylus was recorded in much
smaller densities (<0.01 individuals m-2). Despite a comprehensive survey of invertebrates done between 1999 and 2003, neither
of these species was previously detected in the Guadiana estuary. These observations may, therefore, coincide with the
introduction of these species to the Guadiana estuary. Small planktonic crustaceans are generally described as the main food
items for B. virginica. Our results show that the presence of the medusa was usually associated with a reduction of densities of
all zooplanktonic organisms, including eggs of Engraulis encrasicolus. The reduction of planktonic biomass could have severe
implications for organisms at upper trophic levels, such as E. encrasicolus, which use the Guadiana estuary as a nursery area and
feed mostly on small planktonic crustaceans. Moreover, the potential consumption of eggs by B. virginica could potentially
increase the impact on the nursery function of the estuary. The other alien species detected, P. macrodactylus, appears to be a
strong invader, able to colonise a wide geographical range. It has a strong osmoregulatory capacity, and is known to inhabit a
wide range of salinities, particularly if compared to similar native species (Crangon crangon and Palaemon longirostris). There
is clear potential for the occurrence of competition for food between P. macrodactylus and the native prawn, due to dietary
overlapping. The Guadiana estuary is under Mediterranean climate influence and is expected to be strongly impacted by climatic
changes in the next decades. Other threat-factors are also present, such as increasing regulation by dams, the construction of new
harbors, and increase shipping activity. It is important, therefore, to study the impact of these new invasions in this estuary and,
based on the ecohydrology approach, propose mitigations measures to be applied in this system and other similar ecosystems
worldwide
Coronary Intimal Thickening: Once Again
In a letter to the Editor, Briana and Malamitsi-Puchner1 commented our recently published paper in which we showed that intimal thickening already begins in fetal life and progresses through childhood and adolescence.2 Our work is in line with studies by Barker about the fetal origins of adult disease which led to The Barker Hypothesis, indicating that the pathogenesis of cardiovascular (CV) disease begins in utero.3Briana et al.1 recently evaluated cord blood serum for potentially prognostic biomarkers for CV disease in large-for-gestational-age compared with appropriate-for-gestational-age neonates. Among other biomarkers, the authors studied serum cardiotrophin-1, a cardiomyocyte-produced chemokine that plays a fundamental role in fetal heart development and whose expression is increased by hypoxia, mechanical stress and proinflammatory cytokines such as interleukin (IL) 1b. The authors1 also studied serum levels of cardiac myocytesarcomeral protein titin, involved in sensing and responding to myocardial stress. As a result, Briana et al.1 propose that cord blood serum concentrations of both cardiotrophin-1 and titin could represent prognostic biomarkers for future CV disease.4In addition, another study by Milei et al.5 analyzed autopsy heart samples from 22 fetal sudden intrauterine death and 36 sudden infant death victims, all between the 32nd week of gestation and 1year of age. In 28 out of 58 cases, the mothers were smokers. Coronary lesions were detected in 10 of 12 fetuses and in 15 of 16 infants whose mothers smoked, while only 5cases (2 of 10 fetuses and 3 of 20 infants) arterial lesions were found in cases of nonsmoking mothers (p 1 artery, compared with 25% in the CoHD patients without surgery (p<0.001). Hence, these results suggest a higher rate of coronary intimal hyperplasia in surgically repaired CoHD patients as compared with non-repaired ones.6 This high incidence was correlated with intimal decrease in estrogen receptor α (ERα) expression, an increment in transforming growth factor β1 (TGF-β1) expression and in apolipoprotein B (apoB) deposition, which allowed us to conclude that a decrease in ERα and augmented expression of TGF-β1 expression may contribute to the development of atherosclerotic coronary artery disease in CoHD patients.6,7 A case report illustrating our findings described an aneurysm in the left main coronary artery of a 2-year-old patient. This aneurysm presented intimal hyperplasia and strong apoB deposition.8As mentioned in the Briana and Malamitsi-Puchner letter,1 it is important to search for early biomarkers of CV disease at an early age in order to implement preventive strategies. In this regard, we suggest that special attention should be given to children of smoking mothers and to CoHD patients, particularly if they underwent reparative surgery.Fil: Castilla Lozano, Maria del Rocio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Cardiológicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Cardiológicas; ArgentinaFil: Gutierrez, Christopher P. A.. Universidad de Buenos Aires; ArgentinaFil: Azzato, Francisco. Universidad de Buenos Aires; ArgentinaFil: Ambrosio, Giuseppe. Università di Perugia; ItaliaFil: Milei, Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Cardiológicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Cardiológicas; Argentin
Reversible Notch1 acetylation tunes proliferative signalling in cardiomyocytes
Aims:
The Notch signalling pathway regulates the balance between proliferation and differentiation in several tissues, including the heart. Our previous work has demonstrated that the proliferative potential of neonatal cardiomyocytes relies on Notch1 activity. A deep investigation on the biochemical regulation of the Notch signalling in cardiomyocytes is the focus of the current research.
Methods and results:
We show that the Notch1 intracellular domain is acetylated in proliferating neonatal rat cardiomyocytes and that acetylation tightly controls the amplitude and duration of Notch signalling. We found that acetylation extends the half-life of the protein, and enhanced its transcriptional activity, therefore counteracting apoptosis and sustaining cardiomyocyte proliferation. Sirt1 acted as a negative modulator of Notch1 signalling; its overexpression in cardiomyocytes reverted Notch acetylation and dampened its stability. A constitutively acetylated fusion protein between Notch1 and the acetyltransferase domain of p300 promoted cardiomyocyte proliferation, which was remarkably sustained over time. Viral vector-mediated expression of this protein enhanced heart regeneration after apical resection in neonatal mice.
Conclusion:
These results identify the reversible acetylation of Notch1 as a novel mechanism to modulate its signalling in the heart and tune the proliferative potential of cardiomyocytes
1-(2-Furoyl)-3-(1-naphthyl)thiourea
In the title compound, C16H12N2O2S, the carbonylthiourea group forms dihedral angles of 75.4 (1) and 13.1 (2)°, respectively, with the naphthalene ring system and furan ring. The molecule adopts a trans–cis configuration with respect to the positions of the furoyl and naphthyl groups relative to the S atom across the thiourea C—N bonds. This geometry is stabilized by an N—H⋯·O intramolecular hydrogen bond. In the crystal structure, molecules are linked by N—H⋯S hydrogen bonds, forming centrosymmetric dimers which are interlinked through C—H⋯π interactions
Jasmonate promotes auxin-induced adventitious rooting in dark-grown Arabidopsis thaliana seedlings and stem thin cell layers by a cross-talk with ethylene signalling and a modulation of xylogenesis
Background: Adventitious roots (ARs) are often necessary for plant survival, and essential for successful micropropagation. In Arabidopsis thaliana dark-grown seedlings AR-formation occurs from the hypocotyl and is enhanced by application of indole-3-butyric acid (IBA) combined with kinetin (Kin). The same IBA + Kin-treatment induces AR-formation in thin cell layers (TCLs). Auxin is the main inducer of AR-formation and xylogenesis in numerous species and experimental systems. Xylogenesis is competitive to AR-formation in Arabidopsis hypocotyls and TCLs. Jasmonates (JAs) negatively affect AR-formation in de-etiolated Arabidopsis seedlings, but positively affect both AR-formation and xylogenesis in tobacco dark-grown IBA + Kin TCLs. In Arabidopsis the interplay between JAs and auxin in AR-formation vs xylogenesis needs investigation. In de-etiolated Arabidopsis seedlings, the Auxin Response Factors ARF6 and ARF8 positively regulate AR-formation and ARF17 negatively affects the process, but their role in xylogenesis is unknown. The cross-talk between auxin and ethylene (ET) is also important for AR-formation and xylogenesis, occurring through EIN3/EIL1 signalling pathway. EIN3/EIL1 is the direct link for JA and ET-signalling. The research investigated JA role on AR-formation and xylogenesis in Arabidopsis dark-grown seedlings and TCLs, and the relationship with ET and auxin. The JA-donor methyl-jasmonate (MeJA), and/or the ET precursor 1-aminocyclopropane-1-carboxylic acid were applied, and the response of mutants in JA-synthesis and -signalling, and ET-signalling investigated. Endogenous levels of auxin, JA and JA-related compounds, and ARF6, ARF8 and ARF17 expression were monitored. Results: MeJA, at 0.01 μM, enhances AR-formation, when combined with IBA + Kin, and the response of the early-JA-biosynthesis mutant dde2–2 and the JA-signalling mutant coi1–16 confirmed this result. JA levels early change during TCL-culture, and JA/JA-Ile is immunolocalized in AR-tips and xylogenic cells. The high AR-response of the late JA-biosynthesis mutant opr3 suggests a positive action also of 12-oxophytodienoic acid on AR-formation. The crosstalk between JA and ET-signalling by EIN3/EIL1 is critical for AR-formation, and involves a competitive modulation of xylogenesis. Xylogenesis is enhanced by a MeJA concentration repressing AR-formation, and is positively related to ARF17 expression. Conclusions: The JA concentration-dependent role on AR-formation and xylogenesis, and the interaction with ET opens the way to applications in the micropropagation of recalcitrant species
The crater lake of Ilamatepec (Santa Ana) volcano, El Salvador: insights into lake gas composition and implications for monitoring
We here present the first chemical characterization of the volcanic gas plume issuing from the Santa Ana crater lake, a hyper-acidic crater lake (pH of -0.2 to 2.5) in north-western El Salvador. Our results, obtained during regular surveys in 2017 and 2018 using a Multi-GAS instrument, demonstrate an hydrous gas composition (H2O/SO2 ratios from 32 to 205), and SO2 as the main sulphur species (H2S/SO2 = 0.03-0.1). We also find that gas composition evolved during our investigated period, with the CO2/SO2 decreasing by one order of magnitude from March 2017 (37.2 ± 9.7) to 2018 (<3). This compositional evolution toward more magmatic (SO2-rich) compositions is interpreted in the context of the long-term evolution of the volcano following its 2005 and 2007 eruptions. We find that, in spite of reduced (background-level) seismicity, the magmatic gas supply into the lake was one order of magnitude higher in March 2017 (Total Volatile Flux: 20,200-30,200 t/day; the total volatile flux is the sum of H2O+CO2+SO2+H2 fluxes in our specific case) than in the following periods (Total Volatile Flux: 615-4112 t/day). We propose that the elevated magmatic/hydrothermal transport in March 2017, combined with a 15% reduction in precipitation, caused the volume of the lake to decrease, ultimately reducing its sulfur absorbing and scrubbing capacity, and hence causing the gas plume CO2/SO2 ratio to decrease. The recently observed increases in temperature, acidity and salinity of the lake are consistent with this hypothesis. The small volume of Santa Ana lake, compared to other crater lakes such as the pre-2017 Poás (Costa Rica), Yugama (Japan), Ruapehu (New Zealand) and Kawah Ijen (Indonesia), makes it sensitive to variations in the underlying magmatic-hydrothermal system. We conclude that the installation of a continuous, fully-automated Multi-GAS is highly desirable to monitor any future change in lake plume chemistry, and hence state of volcanic activity.Publishedid 664V. Processi pre-eruttiviJCR Journa
Evaluation of the influence of kyphosis and scoliosis on intervertebral disc extrusion in French bulldogs
Although thoracic vertebral malformations with kyphosis and scoliosis are often considered incidental findings on diagnostic imaging studies of screw-tailed brachycephalic breeds, they have been suggested to interfere with spinal biomechanics and intervertebral disc degeneration. It is however unknown if an abnormal spinal curvature also predisposes dogs to develop clinically relevant intervertebral disc herniations. The aim of this study was to evaluate if the occurrence of thoracic vertebral malformations, kyphosis or scoliosis would be associated with a higher prevalence of cervical or thoracolumbar intervertebral disc extrusion in French bulldogs
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