Objetivo/Contexto: Este trabajo estudia los primeros periódicos escolares chilenos liderados por mujeres, y el papel de las estudiantes de secundaria como mediadoras del saber científico a fines del ...siglo xix y principios del xx. El análisis se enmarca en la expansión y modernización de la prensa, así como en la influencia del positivismo y las reformas educativas que se estaban implementando en Chile en ese periodo, contexto en el que la clase dirigente consideró como una prioridad el conocimiento científico, tanto en su desarrollo como en el acceso a este por parte de la población. Metodología: El artículo se basa en los trabajos de historiadores de la ciencia que han estudiado los públicos o audiencias legas, entre ellas, a las mujeres, como agentes activos en la circulación y generación de nuevo conocimiento. Esta perspectiva teórica se aplica al análisis de las revistas de cuatro liceos femeninos que se acogieron a los planes de estudios válidos para acceder a la universidad en el periodo, y se complementa con otras fuentes, tales como prospectos y documentos administrativos relevantes. Originalidad: El estudio visibiliza el papel de las mujeres en la difusión y apropiación del conocimiento científico y, en específico, de las escolares chilenas en ese contexto, quienes no han sido estudiadas desde la perspectiva aquí planteada. Conclusiones: Pese a la falta de atención que se le ha brindado a este grupo de la población en materia de contribución científica, se demuestra que las estudiantes de secundaria fueron activas lectoras, divulgadoras y productoras de saberes, que gestionaron revistas, generaron redes e hicieron circular el conocimiento más allá de los muros de sus establecimientos educativos.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Expression of hepcidin, the hepatic hormone controlling iron homeostasis, is regulated by bone morphogenetic protein (BMP) signaling. We sought to identify which BMP type II receptor expressed in ...hepatocytes, ActR2a or BMPR2, is responsible for regulating hepcidin gene expression. We studied Bmpr2 heterozygous mice (Bmpr2+/−), mice with hepatocyte-specific deficiency of BMPR2, mice with global deficiency of ActR2a, and mice in which hepatocytes lacked both BMPR2 and ActR2a. Hepatic hepcidin messenger RNA (mRNA) levels, serum hepcidin and iron levels, and tissue iron levels did not differ in wild-type mice, Bmpr2+/− mice, and mice in which either BMPR2 or ActR2a was deficient. Deficiency of both BMP type II receptors markedly reduced hepatic hepcidin gene expression and serum hepcidin levels leading to severe iron overload. Iron injection increased hepatic hepcidin mRNA levels in mice deficient in either BMPR2 or ActR2a, but not in mice deficient in both BMP type II receptors. In addition, in mouse and human primary hepatocytes, deficiency of both BMPR2 and ActR2a profoundly decreased basal and BMP6-induced hepcidin gene expression. These results suggest that BMP type II receptors, BMPR2 and ActR2a, have redundant roles in the regulation of hepatic hepcidin gene expression and iron metabolism.
•Presence of either ActR2a or BMPR2 in hepatocytes is sufficient to maintain hepatic hepcidin gene expression and iron metabolism.•Deficiency of both BMP type II receptors in hepatocytes induces iron overload.
In this work, a colorimetric indicator based on gold nanoparticles (AuNP) and a biodegradable and eco-friendly polymer (sodium alginate, Alg.), was developed for the real-time detection of fish ...spoilage products. The AuNPs and the colorimetric indicator were characterized using UV-VIS, FTIR spectroscopies, TGA, DSC, XRD, TEM, and colorimetry. The UV-VIS spectrum and TEM showed the successful synthesis, the spherical shape, and the size of AuNPs. The results indicated color changes of the indicator in packaged fish on day 9 of storage at a refrigerated temperature (5 °C. These results showed the successful application of the colorimetric indicator in the detection of TVB-N in packaged fish.
Bone morphogenetic protein (BMP) signaling induces hepatic expression of the peptide hormone hepcidin. Hepcidin reduces serum iron levels by promoting degradation of the iron exporter ferroportin. A ...relative deficiency of hepcidin underlies the pathophysiology of many of the genetically distinct iron overload disorders, collectively termed hereditary hemochromatosis. Conversely, chronic inflammatory conditions and neoplastic diseases can induce high hepcidin levels, leading to impaired mobilization of iron stores and the anemia of chronic disease. Two BMP type I receptors, Alk2 (Acvr1) and Alk3 (Bmpr1a), are expressed in murine hepatocytes. We report that liver-specific deletion of either Alk2 or Alk3 causes iron overload in mice. The iron overload phenotype was more marked in Alk3- than in Alk2-deficient mice, and Alk3 deficiency was associated with a nearly complete ablation of basal BMP signaling and hepcidin expression. Both Alk2 and Alk3 were required for induction of hepcidin gene expression by BMP2 in cultured hepatocytes or by iron challenge in vivo. These observations demonstrate that one type I BMP receptor, Alk3, is critically responsible for basal hepcidin expression, whereas 2 type I BMP receptors, Alk2 and Alk3, are required for regulation of hepcidin gene expression in response to iron and BMP signaling.
The bone morphogenetic protein (BMP) type II receptor (BMPR2) has a long cytoplasmic tail domain whose function is incompletely elucidated. Mutations in the tail domain of BMPR2 are found in familial ...cases of pulmonary arterial hypertension. To investigate the role of the tail domain of BMPR2 in BMP signaling, we generated a mouse carrying a Bmpr2 allele encoding a non-sense mediated decay-resistant mutant receptor lacking the tail domain of Bmpr2. We found that homozygous mutant mice died during gastrulation, whereas heterozygous mice grew normally without developing pulmonary arterial hypertension. Using pulmonary artery smooth muscle cells (PaSMC) from heterozygous mice, we determined that the mutant receptor was expressed and retained its ability to transduce BMP signaling. Heterozygous PaSMCs exhibited a BMP7‑specific gain of function, which was transduced via the mutant receptor. Using siRNA knockdown and cells from conditional knockout mice to selectively deplete BMP receptors, we observed that the tail domain of Bmpr2 inhibits Alk2‑mediated BMP7 signaling. These findings suggest that the tail domain of Bmpr2 is essential for normal embryogenesis and inhibits Alk2‑mediated BMP7 signaling in PaSMCs.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Epigenetic silencing of fragile X mental retardation 1 (FMR1) causes fragile X syndrome (FXS), a common inherited form of intellectual disability and autism. FXS correlates with abnormal synapse and ...dendritic spine development, but the molecular link between the absence of the FMR1 product FMRP, an RNA binding protein, and the neuropathology is unclear. We found that the messenger RNA encoding bone morphogenetic protein type II receptor (BMPR2) is a target of FMRP. Depletion of FMRP increased BMPR2 abundance, especially that of the full-length isoform that bound and activated LIM domain kinase 1 (LIMK1), a component of the noncanonical BMP signal transduction pathway that stimulates actin reorganization to promote neurite outgrowth and synapse formation. Heterozygosity for BMPR2 rescued the morphological abnormalities in neurons both in Drosophila and in mouse models of FXS, as did the postnatal pharmacological inhibition of LIMK1 activity. Compared with postmortem prefrontal cortex tissue from healthy subjects, the amount of full-length BMPR2 and of a marker of LIMK1 activity was increased in this brain region from FXS patients. These findings suggest that increased BMPR2 signal transduction is linked to FXS and that the BMPR2-LIMK1 pathway is a putative therapeutic target in patients with FXS and possibly other forms of autism.
Potassium 1-fluorobenzoyltrifluoroborate (FBTFB) salt was characterized using Fourier Transformed Infrared (FT-IR) and Raman solid-state spectroscopies as well as ultraviolet–visible spectroscopy in ...aqueous solution. The functional hybrid B3LYP with the 6-311++G** basis set have optimized the structures of salt in gas phase and in aqueous solution with CS symmetries. In solution, the influence of solvent was studied at the same level of theory with the integral equation formalism variant polarised continuum method (IEFPCM) and the universal solvation model. FBTFB has evidenced the lower solvation energy (−81.54 kJ/mol), as compared with other trifluoroborate salts probably due to the presence of F in the 1st position of phenyl ring that decreases the solubility of this salt. NBO studies clearly support the ionic characteristics of K+F− and K+O− bonds and the high energy values of LPF17→ LP*B14 transitions (ΔΕn→n*) while AIM analyses suggest a high stability of salt in both media due to three ionic and one C–H⋅⋅⋅F interactions. Analyses of frontier orbitals have suggested that the FBTFB salt is more reactive in solution than in gas phase and, than 2-phenylacetyl-trifluoroborate (PTFB) in the two media possibly because FBTFB presents higher global electrophilicity (ω) and nucleophilicity indexes (E) in both media than PTFB. Here, the calculated harmonic force fields, scaled force constants and complete assignments of all vibration normal modes expected for FBTFB in both media are reported. Predicted IR, Raman and UV–Visible spectra have shown good concordance when they are compared with the corresponding experimental ones.
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•FBTFB salt was characterized by the FT-IR, Raman and the UV–visible spectra.•FBTFB has evidenced a low solvation energy as compared with similar salts.•NBO studies support clearly the ionic characteristics of K+F− and K+O− bonds.•AIM analyses suggest a high stability of salt in both media.•FBTFB present high global electrophilicity and nucleophilicity indexes in both media.
Bone morphogenetic protein (BMP) signaling contributes to the development of cardiac hypertrophy. However, the identity of the BMP type I receptor involved in cardiac hypertrophy and the underlying ...molecular mechanisms are poorly understood. By using quantitative PCR and immunoblotting, we demonstrated that BMP signaling increased during phenylephrine-induced hypertrophy in cultured neonatal rat cardiomyocytes (NRCs), as evidenced by increased phosphorylation of Smads 1 and 5 and induction of Id1 gene expression. Inhibition of BMP signaling with LDN193189 or noggin, and silencing of Smad 1 or 4 using small interfering RNA diminished the ability of phenylephrine to induce hypertrophy in NRCs. Conversely, activation of BMP signaling with BMP2 or BMP4 induced hypertrophy in NRCs. Luciferase reporter assay further showed that BMP2 or BMP4 treatment of NRCs repressed atrogin-1 gene expression concomitant with an increase in calcineurin protein levels and enhanced activity of nuclear factor of activated T cells, providing a mechanism by which BMP signaling contributes to cardiac hypertrophy. In a model of cardiac hypertrophy, C57BL/6 mice treated with angiotensin II (A2) had increased BMP signaling in the left ventricle. Treatment with LDN193189 attenuated A2-induced cardiac hypertrophy and collagen deposition in left ventricles. Cardiomyocyte-specific deletion of BMP type I receptor ALK2 (activin-like kinase 2), but not ALK1 or ALK3, inhibited BMP signaling and mitigated A2-induced cardiac hypertrophy and left ventricular fibrosis in mice. The results suggest that BMP signaling upregulates the calcineurin/nuclear factor of activated T cell pathway via BMP type I receptor ALK2, contributing to cardiac hypertrophy and fibrosis.
Annonaceous acetogenin (ACG), motrilin was experimentally isolated and characterized by using the FT-IR and FT-Raman spectra in the solid state and by UV-visible spectrum in methanol solution. The ...main bands observed in the vibrational spectra were assigned combining their predicted spectra with hybrid functional B3LYP/6-31G* calculations. The structural, electronic and topological properties were predicted for motrilin in gas phase and in methanol solution. The corrected solvation energy by ZPVE and by total non-electrostatic terms reveals for motrilin in methanol solution a value of −147.54 kJ/mol. The NPA charges have evidenced higher changes on the atoms of motrilin in methanol solution than the values in gas phase while the studies of electrostatic potentials have revealed strongest nucleophilic regions on the two O atoms of lactone ring while electrophilic sites on the H atoms of OH groups. Both NBO and AIM studies support the high stabilities of motrilin, especially in methanol solution probably due to the solute-solvent association phenomenom, as suggested by the expansion of volume in solution and by the H bond formation in this medium predicted by the AIM program. A higher reactivity of motrilin in methanol solution was evidenced by using the frontier orbitals while both electrophilicity and nucleophilicity indexes show values for motrilin similar to those observed in the antimicrobial thione agent. The predicted IR, Raman and UV-visible spectra has evidenced reasonable concordance with the corresponding experimental ones.
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•Motrilin was isolated and characterized by the FT-IR, FT-Raman and UV-visible spectra.•The corrected solvation energy for motrilin in methanol solution is of −147.54 kJ/mol.•NPA charges have evidenced higher changes of motrilin in methanol solution.•NBO and AIM studies support the high stabilities of motrilin in methanol solution.•The frontier orbitals evidence a higher reactivity of motrilin in methanol solution.
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