252 research outputs found
Dificultades con porcentajes en maestros en formación
No full textSe planteó una investigación con 52 estudiantes de segundo año del Grado de Educación Primaria de la Universidad de Córdoba durante el curso 2018/19 para determinar cuáles son los tipos de situaciones que les generan mayor dificultad. Se les aplicó un test inicial de conocimientos. Para ello se utilizó una batería de ejercicios de los tres tipos antes indicados y tres problemas que implican porcentajes. Los ejercicios y problemas fueron tomados de Autor (Maz-Machado y Gutiérrez, 2008)
Hitting the detection limit in cAMP signaling
No full textSupplementary material to the paper “Hitting the detection limit in cAMP signaling.”
Function, 2022
Florencia Klein1, Matías R. Machado1, Sergio Pantano1*
1 Institut Pasteur de Montevideo, Montevideo, Uruguay.
*[email protected]
This entry contains structure files in PDB (Protein Data Bank) format representing cAMP nanodomains within a sarcomere myofibril. The 3D nanodomain was constructed by integrative modeling taking together information obtained from simulations, homology models, cryo-electron microscopy for myosins and actin filaments, and structural and sequence alignments.
The primary source was the available experimental structures in the PDB (https//:www.rcsb.org). However, due to the difficulty of getting experimental structures from the same organism and cellular stage, it was necessary to appeal to homology models to construct some components. Notice that the model was built to gain gross insights into the structure of the nanosignalosome. The model contains steric clashes and is not suitable as the starting point for molecular simulations.
The tridimensional model was created by replicating a hexagonal unit in the space by applying a TCL script (see attached file Build_Myofiber.tcl). This script allows the construction of a myosin fibril, including the thin and thick filaments, including the proteins presented in Figure 1B of Klein et al. (Function, 2022).
Tables 1 and 2 show the corresponding PDB structures and the chain of each component to be visualized, respectively.
Table 1. PDB structure for each protein component in nanodomain.
STRUCTURE
PDB ID:
Actin filaments and Tropomyosin
2W4U.
Troponins Complex (Tns)
1J1D
Protein Kinase A (PKA)
3J4Q
Thick Filament
3DTP
Titin and MyBP-C
3LPW
Table 2. Chain identifiers within the PDB file in each nanodomain.
Thin Filament
PKA- Catalytic Domain
d and e
PKA-D/D and Regulatory Domain
b and c
TnC
3 6 9 and O
TnT
1 4 7 and Y
TnI
2 5 8, and Z
Tropomyosin
A to C T to X
Actin filaments
D to S
CUTie
t
Thick Filament
Myosin- Heavy chain
A to F, X to Z and 9
Myosin-S2 chain
G to I and g to i
Myosin- Light chain
a to f and 1 to 8
Titin
L to W
MyBP-C
J and
Application of the DNA-Specific stain methyl green in the fluorescent labeling of embryos
No full textMethyl green has long been known as a histological stain with a specific affinity for DNA, although its fluorescent properties have remained unexplored until recently. In this article, we illustrate the method for preparing a methyl green aqueous stock solution, that when diluted can be used as a very convenient fluorescent nuclear label for fixed cells and tissues. Easy procedures to label whole zebrafish and chick embryos are detailed, and examples of images obtained shown. Methyl green is maximally excited by red light, at 633 nm, and emits with a relatively sharp spectrum that peaks at 677 nm. It is very inexpensive, non-toxic, highly stable in solution and very resistant to photobleaching when bound to DNA. Its red emission allows for unaltered high resolution scanning confocal imaging of nuclei in thick specimens. Finally, this methyl green staining protocol is compatible with other cell staining procedures, such as antibody labeling, or actin filaments labeling with fluorophoreconjugated phalloidi
Another Coarse Grain Model for Aqueous Solvation: WAT FOUR?
No full textBiological processes occur on space and time scales that are often unreachable for fully atomistic simulations. Therefore, simplified or coarse grain (CG) models for the theoretical study of these systems are frequently used. In this context, the accurate description of solvation properties remains an important and challenging field. In the present work, we report a new CG model based on the transient tetrahedral structures observed in pure water. Our representation lumps approximately 11 WATer molecules into FOUR tetrahedrally interconnected beads, hence the name WAT FOUR (WT4). Each bead carries a partial charge allowing the model to explicitly consider long-range electrostatics, generating its own dielectric permittivity and obviating the shortcomings of a uniform dielectric constant. We obtained a good representation of the aqueous environment for most biologically relevant temperature conditions in the range from 278 to 328 K. The model is applied to solvate simple CG electrolytes developed in this work (Na+, K+, and Cl-) and a recently published simplified representation of nucleic acids. In both cases, we obtained a good resemblance of experimental data and atomistic simulations. In particular, the solvation structure around DNA, partial charge neutralization by counterions, preference for sodium over potassium, and ion mediated minor groove narrowing as reported from X-raycrystallography are well reproduced by the present scheme. The set of parameters presented here opens the possibility of reaching the multimicroseconds time scale, including explicit solvation, ionic specificity, and long-range electrostatics, keeping nearly atomistic resolution with significantly reduced computational cost.Fil: Darre, Leonardo. Instituto Pasteur de Montevideo; UruguayFil: Machado, Matías. Instituto Pasteur de Montevideo; UruguayFil: Dans, Pablo. Instituto Pasteur de Montevideo; UruguayFil: Herrera, Fernando Enrique. Universidad Nacional del Litoral; ArgentinaFil: Pantano, Sergio. Instituto Pasteur de Montevideo; Urugua
Author response
No full textInternational audienceTwo-component systems (TCS) are protein machineries that enable cells to respond to input signals. Histidine kinases (HK) are the sensory component, transferring information toward downstream response regulators (RR). HKs transfer phosphoryl groups to their specific RRs, but also dephosphorylate them, overall ensuring proper signaling. The mechanisms by which HKs discriminate between such disparate directions, are yet unknown. We now disclose crystal structures of the HK:RR complex DesK:DesR from Bacillus subtilis, comprising snapshots of the phosphotransfer and the dephosphorylation reactions. The HK dictates the reactional outcome through conformational rearrangements that include the reactive histidine. The phosphotransfer center is asymmetric, poised for dissociative nucleophilic substitution. The structural bases of HK phosphatase/phosphotransferase control are uncovered, and the unexpected discovery of a dissociative reactional center, sheds light on the evolution of TCS phosphotransfer reversibility. Our findings should be applicable to a broad range of signaling systems and instrumental in synthetic TCS rewiring
Insect Antifeedant Components of Senecio fistulosus var. fistulosus—Hualtata
No full text© The Author(s).From a bioactive methanolic extract of Senecio fistulosus, the antifeedant effects of the alkaloidal and non-alkaloidal fractions were tested against the insects Spodoptera littoralis, Myzus persicae and Rhopalosiphum padi, with the non-alkaloidal fraction being antifeedant. The phytochemical study of the non-alkaloidal fraction of S. fistulosus, resulted in the isolation of four compounds, two 9-oxo-furanoeremophilanes (1, 2), an eremophilanolide, 1β,10β-epoxy-6-acetoxy-8α-hydroxy-eremofil-7(11)-en-8β,12-olide (3) and a maaliol derivative (4). The alkaloidal fraction yielded two known pyrrolizidine alkaloids (5, 6). Compounds 1, 3 and 4 are new natural products. Furanoeremophilane 2 was a strong antifeedant against S. littoralis and maaliane 4 inhibited the settling of M. persicaeThis work has been supported by grants CTQ2015-64049-C3-1-R, (MINECO/FEDER), UMAG 027103-026703 (Dirección de Investigación, Chile) and a JAEPRE-DOC-CSIC predoctoral fellowship to L.R.V.Peer reviewe
Gênero e educação física: o que diz a produção teórica brasileira dos anos 80 e 90? /
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Desportos.Ao olhar, atentamente, a produção acadêmica brasileira, relacionada com o campo de estudos de gênero e dos estudos feministas, constatei uma grande performance teórica e variadas tentativas de diálogo entre os diversos campos do saber, inclusive com o campo específico da Educação Física/Esporte(EF/Esporte). Isto tem se dado, sobretudo, nos últimos anos, considerando o caráter plural das concepções de feminino e de masculino vigente na atual sociedade globalizada, na qual o conceito de gênero tem permitido, entre outras instâncias, a compreensão de construções históricas em torno do sexo, enfatizando, os mecanismos e as instituições culturais e sociais que estão envolvidas nesta construção. Com a intenção de contribuir com esse debate, ao longo da trajetória deste estudo, discorro sobre algumas dimensões de gênero desenvolvidas para a EF/Esporte e suas contribuições na compreensão da organização social. Neste sentido, o texto que se segue, apresentado em três capítulos, intitulados: primeiro, o ponto de partida; segundo, nas teias do gênero; terceiro, gênero e educação física: refletindo sobre as pesquisas dos anos 80 e 90; diz sobre o que se convencionou chamar "estudos de gênero na/para a EF/Esporte. Como esta se apropriou desse conceito, e como tem classificado como sendo "estudos de gênero" esse ou aquele trabalho. Enfim, como se encontra o estado atual do conhecimento sobre gênero na EF/Esporte? Como base de análise e interpretação, foi utilizado o material empírico relacionado à produção científica, na forma de dissertação e tese, oriundas dos programas de pós-graduação brasileiros em Educação e Educação Física, em nível de mestrado e doutorado, décadas de 80 e 90. Para tanto, é utilizada a técnica de análise de conteúdo, levando em conta algumas categorias selecionadas, entre as quais, a) Temáticas abordadas; b) Problemática e questões priorizadas; c) Concepções/abordagens; d) Relação sujeito/objeto - sexo do pesquisador; e) lugar onde foram produzidos os estudos; f) Orientação, co-orientação e composição de bancas examinadoras; g) Escolas de pensamento, propostas e sugestões. Observei que a produção acadêmico-científica, num primeiro momento, deteve-se em analisar os estereótipos e a existência do sexismo do ponto de vista bio-psico-fisiológico, mais recentemente, os estudos apresentam uma dimensão temática ampliada, situando-se em torno de três eixos: sexualidade, política e cultura. Ficou evidenciado, ainda, na leitura das dissertações e teses, um certo avanço a respeito das questões tratadas, no entanto, acredito que há de se cuidar sobre os rumos que poderão tomar as pesquisas neste campo teórico, pois freqüentemente tem sido utilizadas perspectivas teórico-metodológicas incompatíveis entre si, e aí são cometidos, então, alguns equívocos, onde certos conceitos são tidos como equivalentes, sem, no entanto, o serem
Split the Charge Difference in Two! a Rule of Thumb for Adding Proper Amounts of Ions in MD Simulations
No full textSIRAH tools: mapping, backmapping and visualization of coarse-grained models.
No full textInternational audienceCoarse-grained (CG) models reduce the cost of molecular dynamics simulations keeping the essence of molecular interactions. Still, the diversity of CG representations (sizes, connectivity, naming, etc.) hampers the handling and visualization of such models. SIRAH Tools comprises a set of utilities to convert all-atoms coordinates to arbitrary residue-based CG schemes, write GROMACS' topological information at any resolution into PSF format and a VMD plugin to visualize, analyze and retrieve pseudo-atomistic information from CG trajectories performed with the SIRAH force field. These tools facilitate the use of intricate CG force fields outside the small developer's community
Matías Ramón Martínez y la Revista de Extremadura
No full text[ES]: En este trabajo se resumen los artículos publicados por M. R. Martínez en la Revista de Extremadura entre 1899 y 1904. Se estudia el comportamiento del autor en la revista, así como los temas tratados, las zonas investigadas o la regularidad de sus contribuciones. Entre sus colaboraciones destacan la presentación de documentos inéditos, las noticias sobre hallazgos arqueológicos, breves historias locales y críticas a libros históricos.[EN]: This paper summarizes articles published by M. R. Martinez in Revista de Extremadura between 1899 and 1904. We study the behavior of the author in the magazine, as well as topics, investigated areas or the regularity of his contributions. This collaborations include the presentation of unpublished documents news about archaeological finds, brief local stories and criticism of historical books.Peer reviewe
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