Influences of atrazine on gonadal differentiation in Xenopus laevis tadpoles during metamorphosis

Xenopus laevis tadpoles were exposed for 48, 96 and 144 h during sexual differentiation to 1.8, 19 and 48 og/L atrazine. Following the exposure, tadpoles were microdissected for histological examination of the gonadal-kidney complex. The experimental tadpoles showed no significant difference in body weight, body length and in their development among the treatments. However, quantitative histological analysis of the gonads revealed a significant reduction of testicular volume, primary spermatogonial cell nests, and nursing cells in males as atrazine concentration and length of exposure increased. Females showed significant declines in primary oogonia cells and a significantly higher frequency of atresia with increasing atrazine concentration and length of exposure. The presence of a Wilms-like tumour was reported for the first time in tadpoles following exposure to atrazine. Qualitative histological analysis of the kidney showed a significant increase in the incidence of Renal Embryonal Adenosarcoma in all atrazine treated tadpoles. Females showed a significantly higher risk from developing tumours and tumour incidence as compared to males. These results suggests that the present non observable effect level (NOEL) for aquatic ecosystem of 20og/L atrazine should be reconsidered

Aplicación del juego del caos para secuencias de aminoácidos

El desarrollo de este trabajo comienza con una breve descripción de las ideas de la geometría fractal, donde se explica de forma breve las ideas principales, las cuales dan origen a una geometría que describe mas realistamente formas presentes en la naturaleza, ya que “las nubes no son esferas, las montañas no son conos, ni las costas son círculos” (Mandeldrot, 1982). Los trabajos del matemático Felix Hausdorff y del físico Lewis Fry Richardson, ayudaron al matemático Benoît Mandelbrot a crear una nueva geometría llamada Geometría Fractal. La sección 2 habla sobre los orígenes y la construcción de esta geometría, ademas se describen conceptos importantes como el Operador de Hutchinson, dimensión fractal y auto similaridad, conceptos que son importantes para la obtención de imágenes fractales. En la sección 3 estudiamos el algoritmo del Juego del Caos y como este algoritmo puede ser usado para observar gráficamente como secuencias aparentemente aleatorios como lo es el ADN presentan patrones muy bien definidos, siendo estas imágenes fractales a las cuales llamaremos firmas genómicas. Deben tenerse algunas consideraciones importantes como el punto semilla, el tablero de juego y la localización de puntos en las imágenes resultantes. osteriormente estudiamos brevemente las cadenas de Marcov y la relación que estas presentan con las secuencias de ADN, y como las propiedades de las cadenas Marcovianas pueden ser aplicadas al ADN, también son estudiadas las matrices de transición y algunos ejemplos que ilustran este tipo de cadenas. En la sección 5 se exponen algunos aspectos biológicos importantes como lo es la síntesis de proteínas la cual fue el parteaguas para la investigación de la sección 6 en la cual se estudia la exención del Juego del Caos para secuencias proteicas, en la cual se presentan algunas limitaciones, siendo dos de ellas que que las regiones dentro de las firmas genómicas no son homogéneas y por otro lado la superposición de puntos en la misma, motivo por el cual en la sección 7 se presenta un nuevo algoritmo el cual es usado para generar fractales estrictamente autosimilares. Posteriormente obtenemos algunas imágenes de secuencias de proteínas las cuales son comparadas con las mismas imágenes de secuencias de proteínas obtenidas en la sección 6. 538 |a TESIUAM

Relación de la salud mental positiva y el autocuidado de los estudiantes del X semestre de la Escuela Profesional de Enfermería de la Universidad Católica de Santa María, Arequipa 2020

Objetivo: Determinar la relación que existe entre la salud mental positiva y el autocuidado de los estudiantes del X semestre de la Escuela Profesional de Enfermería de la universidad. Material y Métodos: La metodología empleada fue de tipo de campo, con un enfoque cuantitativo de nivel descriptivo correlacional con un diseño no experimental, de corte transversal. La muestra estuvo formada por 33 estudiantes. La técnica utilizada fue el cuestionario y como instrumentos se utilizaron dos cédulas de preguntas, una para la medición del nivel de la salud mental positiva y otra para medir el nivel de autocuidado. Resultados: Se determinó la existencia de una relación muy fuerte y significativa dada por un coeficiente de correlación de Spearman de 0.874 entre el nivel de la salud mental positiva y el nivel de autocuidado, con tendencia muy buena a perfecta, lo que indica una relación fuerte, es decir que mientras mejor sea el nivel de autocuidado mayor será el nivel de salud mental positiva que presenten los estudiantesTesi

Cómo a partir del juego de roles sociales fortalecer la comunicación asertiva en los niños de la Institución Educativa Técnica Felipe Salame, sede Cristales

https://docs.google.com/document/d/1k-chuGtSi7utAmfqD88jMYE9Sn5DDf8u/edit?usp=sharing&ouid=107241943969083420388&rtpof=true&sd=trueResumen Este proyecto de investigación se basa sobre el juego de roles sociales para fortalecer la comunicación asertiva en los niños de la institución educativa técnica Felipe Salame, sede Cristales. A través de ejercicios de recolección de datos, observación, toma de evidencias, analizar comportamientos, comprender expresiones, emociones etc., se logró evidenciar falencias relacionadas al desarrollo comunicativo de los niños y niñas, pues su lenguaje, acompaño de actos comportamentales afectaba los procesos sociales y con vivenciales del aula. El proceso de investigación del proyecto se desarrolló en varias fases que permitieron recopilar al contenido de este documento.This research project is based on social role playing to strengthen assertive communication in children at the Felipe Salame technical educational institution, Cristales headquarters. Through exercises of data collection, observation, taking evidence, analyzing behaviors, understanding expressions, emotions, etc., it was possible to demonstrate shortcomings related to the communicative development of boys and girls, since their language, accompanied by behavioral acts, affected the processes. Social and coexistence of the classroom. The research process of the project was developed in several phases that allowed the content of this document to be compile

Genome-wide approaches for identification of nuclear receptor target genes

Large-scale genomics analyses have grown by leaps and bounds with the rapid advances in high throughput DNA sequencing and synthesis techniques. Nuclear receptor signaling is ideally suited to genomics studies because receptors function as ligand-regulated gene switches. This review will survey the strengths and limitations of three major classes of high throughput techniques widely used in the nuclear receptor field to characterize ligand-dependent gene regulation: expression profiling studies (microarrays, SAGE and related techniques), chromatin immunoprecipitation followed by microarray (ChIP-on-chip), and genome-wide in silico hormone response element screens. We will discuss each technique, and how each has contributed to our understanding of nuclear receptor signaling

Development, standardization and refinement of procedures for evaluating effects of endocrine active compounds on development and sexual differentiation of Xenopus laevis

Xenopus laevis has been introduced as a model to study effects of endocrine-active compounds (EAC) on development and sexual differentiation. However, variable and inconsistent data have raised questions about the reliability of the test methods applied. The current study was conducted in two laboratories to develop, refine, and standardize procedures and protocols. Larvae were exposed in flow-through systems to 17β-estradiol (E2), at concentrations from 0.2 to 6.0 μg E2 L−1 in Experiment 1A, and 0.015 to 2.0 μg E2 L−1 in Experiment 1B. In both studies survival (92%, 99%) and percentage of animals that completed metamorphosis (97%, 99%) indicated reproducible biological performance. Furthermore, minor variations in husbandry led to significant differences in snout-to-vent length, weight, and gonad size. In Experiment 1A, almost complete feminization occurred in all E2 treatment groups whereas a concentration response was observed in Experiment 1B resulting in an EC50 of 0.12 μg E2 L−1. The final verified protocol is suitable for determining effects of EAC on development and sexual differentiation in X. laevis

Experimental study of noise levels in critical areas of towns of Cerete, Planeta Eica, Sahagun and Montelibano of Cordoba department

Esta investigación determinó puntos críticos de emisión de ruido generados en diferentes zonas del casco urbano de los municipios de Cereté, Planeta Rica, Montelíbano y Sahagún en jurisdicción de la Corporación Autónoma Regional de los Valles del Sinú y San Jorge -CVS-, considerando como indicadores de calidad acústica el nivel sonoro continuo equivalente con ponderación A (Leq), expresado en decibeles A [dB(A)], los niveles máximos y mínimos, entre otros. Los resultados de la calidad acústica de los diferentes municipios se compararon con los estándares máximos permisibles de niveles de emisión de ruido estipulados en la Norma Colombiana vigente, Resolución 0627 de 2006 del Ministerio de Ambiente, Vivienda y Desarrollo Territorial. Se consideró el sector o subsector estipulado en el Plan de Ordenamiento Territorial de cada municipio, de tal manera que permitiera establecer acciones prioritarias y/o requeridas para evitar o contrarrestar las afectaciones a la salud y el ambiente.Abstract: This investigation determined noise emission critical points generated in different urban areas of Cereté, Planeta Rica, Montelibano and Sahagun, all these under the authority of the Regional Autonomous Corporation of the valleys of the Sinu and San Jorge rivers -CVS-, considered as acoustics indicators quality noise level “A” weighted equivalent continuous (Leq), expressed in decibels [dB (A)], the maximum and minimum levels, among others. The results of the acoustic quality of the different municipalities were compared to the standard maximum permissible noise emission levels stipulated and according to in the current Colombian standard, 0627 Resolution, 2006 of the Environment Ministry, Housing and Territorial Development Office. It was considered the sector or subsector stipulated in the Land Use Plan for each municipality, so that would establish priority actions and / or required to prevent or counteract the effects on population health and the environment itself

The Herbicide Atrazine Activates Endocrine Gene Networks via Non-Steroidal NR5A Nuclear Receptors in Fish and Mammalian Cells

Atrazine (ATR) remains a widely used broadleaf herbicide in the United States despite the fact that this s-chlorotriazine has been linked to reproductive abnormalities in fish and amphibians. Here, using zebrafish we report that environmentally relevant ATR concentrations elevated zcyp19a1 expression encoding aromatase (2.2 µg/L), and increased the ratio of female to male fish (22 µg/L). ATR selectively increased zcyp19a1, a known gene target of the nuclear receptor SF-1 (NR5A1), whereas zcyp19a2, which is estrogen responsive, remained unchanged. Remarkably, in mammalian cells ATR functions in a cell-specific manner to upregulate SF-1 targets and other genes critical for steroid synthesis and reproduction, including Cyp19A1, StAR, Cyp11A1, hCG, FSTL3, LHß, INHα, αGSU, and 11ß-HSD2. Our data appear to eliminate the possibility that ATR directly affects SF-1 DNA- or ligand-binding. Instead, we suggest that the stimulatory effects of ATR on the NR5A receptor subfamily (SF-1, LRH-1, and zff1d) are likely mediated by receptor phosphorylation, amplification of cAMP and PI3K signaling, and possibly an increase in the cAMP-responsive cellular kinase SGK-1, which is known to be upregulated in infertile women. Taken together, we propose that this pervasive and persistent environmental chemical alters hormone networks via convergence of NR5A activity and cAMP signaling, to potentially disrupt normal endocrine development and function in lower and higher vertebrates

Multitarget Drugs: an Epigenetic Epiphany

Epigenetics refers to changes in a biological phenotype that are not due to an underlying change in genotype. In eukaryotes, epigenetics involves a set of chemical modifications of the DNA and the histone proteins in nucleosomes. These dynamic changes are carried out by enzymes and modulate protein–protein and protein–nucleic acid interactions to determine whether specific genes are expressed or silenced. Both the epigenetic enzymes and recognition domains are currently important drug discovery targets, particularly for the treatment of cancer. This review summarizes the progress of epigenetic targets that have reached a clinical stage: DNA methyltransferases, histone deacetylases, lysine methyltransferases, lysine demethylases, and bromodomains; this is followed by a comprehensive survey of multitarget drugs that have included an epigenetic target as one of their mechanisms of action

Contrasting roles for all-trans retinoic acid in TGF-β–mediated induction of Foxp3 and Il10 genes in developing regulatory T cells

Extrathymic induction of regulatory T (T reg) cells is essential to the regulation of effector T cell responses in the periphery. In addition to Foxp3, T reg cell expression of suppressive cytokines, such as IL-10, is essential for peripheral tolerance, particularly in the intestines. TGF-β has been shown to induce expression of Foxp3 as well as IL10 and the vitamin A metabolite; all-trans retinoic acid (RA [at-RA]) has been found to enhance the former. We report that in contrast to its enhancement of TGF-β–mediated Foxp3 induction, at-RA potently inhibits the TGF-β–mediated induction of Il10 in naive CD4 T cells. Thus, mucosal DC subsets that are active producers of at-RA inhibit induction of Il10 in naive CD4 T cells while promoting induction of Foxp3. Accordingly, mice with vitamin A deficiency have increased numbers of IL-10–competent T reg cells. Activation of DCs by certain Toll-like receptors (TLRs), particularly TLR9, suppresses T cell induction of Foxp3 and enables induction of Il10. Collectively, our data indicate that at-RA has reciprocal effects on the induction of Foxp3 and Il10 in developing CD4+ T reg cells and suggest that TLR9-dependent inhibition of at-RA production by antigen-presenting cells might represent one mechanism to promote the development of IL-10–expressing T cells