¿Tips? Formulación de proyectos

La presentación brinda una serie de consejos para la formulación de proyectos de investigación, enfatizando aspectos a considerar para garantizar un buen desarrollo y gestión del proceso.UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de QuímicaUCR::Vicerrectoría de Investigació

Molecular data indicate that Rhytidhysteron rufulum (ascomycetes, Patellariales) in Costa Rica consists of four distinct lineages corroborated by morphological and chemical characters

Introduction Recent estimates of the number of fungal species worldwide predict a minimal number of over 700 K specie

Identification of Anziaic Acid, a Lichen Depside from Hypotrachyna sp., as a New Topoisomerase Poison Inhibitor

Topoisomerase inhibitors are effective for antibacterial and anticancer therapy because they can lead to the accumulation of the intermediate DNA cleavage complex formed by the topoisomerase enzymes, which trigger cell death. Here we report the application of a novel enzyme-based high-throughput screening assay to identify natural product extracts that can lead to increased accumulation of the DNA cleavage complex formed by recombinant Yersinia pestis topoisomerase I as part of a larger effort to identify new antibacterial compounds. Further characterization and fractionation of the screening positives from the primary assay led to the discovery of a depside, anziaic acid, from the lichen Hypotrachyna sp. as an inhibitor for both Y. pestis and Escherichia coli topoisomerase I. In in vitro assays, anziaic acid exhibits antibacterial activity against Bacillus subtilis and a membrane permeable strain of E. coli. Anziaic acid was also found to act as an inhibitor of human topoisomerase II but had little effect on human topoisomerase I. This is the first report of a depside with activity as a topoisomerase poison inhibitor and demonstrates the potential of this class of natural products as a source for new antibacterial and anticancer compounds

Evaluation of three chroroplastic markers for barcoding and for phylogenetic reconstruction purposes in native plants of Costa Rica

DNA barcoding has been proposed as a practical and standardized tool for species identification. However, the determination of the appropriate marker DNA regions is still a major challenge. In this study, we extracted DNA from 27 plant species belonging to 27 different families native of Costa Rica, amplified and sequenced the plastid genes matK and rpoC1 and the intergenic spacer trnH-­psbA. Bioinformatic analyses were performed with the aim of determining the utility of these markers as possible barcodes to discriminate among species and for phylogenetic reconstruction. From the markers selected, the trnH-­psbA spacer was the most variable in terms of genetic distance and the most promising region for barcoding. However, it presented a limited use for constructing phylogenies due to the complexity of its alignment. The locus matK was less variable but was also useful for species discrimination and for phylogenetic tree generation. The rpoC1 region was highly conserved and suitable for phylogenetic studies, but presented a limited utility as a barcode. The marker combination matK and rpoC1 provided the best resolution for establishing valid phylogenetic relationships among the analyzed plant families. In conclusion, more than one marker should be used for plant barcoding purposes, to provide complementary and variable information for the interespecific species discrimination.Se ha propuesto el empleo de un código de barras de ADN como una herramienta práctica y estandarizada para la identificación de especies. Sin embargo, la determinación de los marcadores moleculares apropiados se constituye en todo un reto. En este estudio se ha extraído el ADN de 27 especies de plantas que pertenecen a 27 familias distintas, nativas de Costa Rica, de las cuales se amplificaron y secuenciaron los marcadores matK y rpoC1 del genoma del plastidio y el espaciador intergénico trnH-­psbA. Se realizaron análisis bioinformáticos con el propósito de determinar la utilidad de estos marcadores como posibles códigos de barra para discriminar entre especies y en la reconstrucción filogenética. De los marcadores seleccionados, el espaciador trnH-­psbA fue el más variable en términos de distancia genética y la región más prometedora como código de barras. Sin embargo, presenta limitaciones en la construcción de filogenias debido a la complejidad del alineamiento. El locus matK fue menos variable, pero más útil en la discriminación de especies y en la generación de árboles filogenéticos. La región rpoC1 fue altamente conservada y útil para estudios filogenéticos, pero de utilidad limitada para ser empleada como código de barras. La combinación de los marcadores matK y rpoC1 provee la mejor resolución para establecer relaciones filogenéticas dentro de las familias de plantas analizadas. En conclusión, se requiere más de un marcador molecular para aplicaciones de código de barras y para proveer información complementaria variable para la discriminación de especies inter-específicas.National Institutes of Health /[U01 TW007404­01 ICB]/NIH/Estados Unido

Prevalência e fatores de risco para obesidade em adolescentes René Vallejo Ortiz Polyclinic. Manzanillo. 2016-2017

Obesity in adolescents in Manzanillo constitutes an incipient and complex health problem without sufficient perception of it. With the aim of determining the clinical-epidemiological aspects associated with obesity in adolescents at clinic No. 602, at the René Vallejo Ortiz polyclinic in Manzanillo, in the period from January 2016 to January 2017, a cross-sectional study was conducted or prevalence of adolescents aged between 11 to 19 years. Data processing and analysis was carried out from the information provided in the database created with the Microsoft Office Excel program, which was carried out by means of the summary study of absolute and relative frequencies. In the analysis of association between qualitative variables, Pearson's non-parametric test of independence and the odds ratio test were used. The risk factors that condition obesity include having been a macro-fetus during pregnancy (OR = 5.95), a history of obesity in the family (OR = 3.66), and a history of lipid disorders in the parents (OR = 2, 83). In order to solve the problem of obesity in adolescents, new strategies are required to control the disease, improve the health status of this population and increase the health indicators of the area in question.La obesidad en adolescentes de Manzanillo constituye un problema de salud incipiente y complejo sin suficiente percepción del mismo. Con el objetivo de determinar los aspectos clínico - epidemiológicos asociados a la obesidad en los adolescentes del consultorio No. 602, del policlínico René Vallejo Ortiz, de Manzanillo, en el período comprendido desde enero de 2016 a enero de 2017, se realizó un estudio transversal o de prevalencia de adolescentes en edades comprendidas entre 11 a 19 años. El procesamiento y análisis de datos se realizó a partir de la información suministrada en la base de datos creada con el programa Microsoft Office Excel, lo cual se realizó mediante el estudio resumido de las frecuencias absolutas y relativas. En el análisis de asociación entre variables cualitativas se empleó la prueba no paramétrica de independencia Chi cuadrado de Pearson y la prueba de razón de posibilidades. Los factores de riesgos que condicionan la obesidad incluyen haber sido macrofeto durante el embarazo (OR = 5,95), antecedente de obesidad en la familia (OR = 3,66), y antecedente de trastornos lipídicos en los progenitores (OR = 2,83). Para resolver el problema de la obesidad en adolescentes se requiriere de nuevas estrategias destinadas al control de la enfermedad, el mejoramiento del estado de salud de esta población y el ascenso de los indicadores sanitarios del área en cuestión.A obesidade em adolescentes em Manzanillo constitui um problema de saúde incipiente e complexo sem uma percepção suficiente dele. Com o objetivo de determinar os aspectos clínico-epidemiológicos associados à obesidade em adolescentes da clínica nº 602, na policlínica René Vallejo Ortiz em Manzanillo, no período de janeiro de 2016 a janeiro de 2017, foi realizado um estudo transversal ou prevalência de adolescentes com idade entre 11 e 19 anos. O processamento e análise dos dados foram realizados a partir das informações fornecidas no banco de dados criado com o programa Microsoft Office Excel, realizado por meio do estudo sumário das frequências absolutas e relativas. Na análise da associação entre variáveis qualitativas, foram utilizados o teste não paramétrico de independência e o odds ratio. Os fatores de risco que condicionam a obesidade incluem ter sido um macro-feto durante a gravidez (OR = 5,95), histórico de obesidade na família (OR = 3,66) e histórico de distúrbios lipídicos nos pais (OR = 2, 83) Para solucionar o problema da obesidade em adolescentes, novas estratégias são necessárias para controlar a doença, melhorar o estado de saúde dessa população e aumentar os indicadores de saúde da área em questão

Titration-based screening for evaluation of natural product extracts: identification of an aspulvinone family of luciferase inhibitors

The chemical diversity of nature has tremendous potential for discovery of new molecular probes and medicinal agents. However, sensitivity of HTS assays to interfering components of crude extracts derived from plants, macro- and microorganisms has curtailed their use in lead discovery efforts. Here we describe a process for leveraging the concentration-response curves (CRCs) obtained from quantitative HTS to improve the initial selection of “actives” from a library of partially fractionated natural product extracts derived from marine actinomycetes and fungi. By using pharmacological activity, the first-pass CRC paradigm aims to improve the probability that labor-intensive subsequent steps of re-culturing, extraction and bioassay-guided isolation of active component(s) target the most promising strains and growth conditions. We illustrate how this process identified a family of fungal metabolites as potent inhibitors of firefly luciferase, subsequently resolved in molecular detail by x-ray crystallography

Comparación de metodologías de extracción para limoneno y carvona en lippia alba usando cromatografía de gases.

Abstract Different plants drying procedures, hydrodistillation and solvent extraction by sonication were evaluated for the essential oil extraction of Lippia alba. Quantitative analysis of the markers limonene and carvone was performed in the extracts by gas chromatograph with flame ionization detection (GC-­FID). Experimental precision, accuracy, specificity, linearity, limits of detection and quantitation were addressed. Lyophilization as a drying procedure and solvent extraction by sonication using ethyl acetate showed the best results regarding the highest concentration for marker compounds.Diferentes procedimientos de secado, extracción mediante disolventes e hidrodestilación se evaluaron para la extracción del aceite esencial de Lippia alba. Se utilizaron los compuestos limoneno y carvona como marcadores para el análisis cuantitativo mediante cromatografía de gases con ionización de llama (GC-­FID). Se definió la precisión, exactitud, especificidad, linealidad y los límites de detección y cuantificación para el análisis. La liofilización como método de secado y la extracción con acetato de etilo utilizando baño ultrasónico mostraron los mejores resultados en función de la obtención de la mayor cantidad de los compuestos marcadores

Recolecta de artrópodos para prospección de la biodiversidad en el Área de Conservación Guanacaste, Costa Rica

artículo -- Universidad de Costa Rica. Escuela de Biología, 2004This study describes the results and collection practices for obtaining arthropod samples to be studied as potential sources of new medicines in a bioprospecting effort. From 1994 to 1998, 1800 arthropod samples of 6-10 g were collected in 21 sites of the Área de Conservación Guancaste (A.C.G) in Northwestern Costa Rica. The samples corresponded to 642 species distributed in 21 orders and 95 families. Most of the collections were obtained in the rainy season and in the tropical rainforest and dry forest of the ACG. Samples were obtained from a diversity of arthropod orders: 49.72% of the samples collected corresponded to Lepidoptera, 15.75% to Coleoptera, 13.33% to Hymenoptera, 11.43% to Orthoptera, 6.75% to Hemiptera, 3.20% to Homoptera and 7.89% to other groups. Different life stages per arthropod species were obtained in most samples, 54.26% of them were adults, 19.90% corresponded to larvae, 6.46% to pupae, 6.12% to pre-pupae, 2.07% to nymphs and 3.74% to other stages. Other materials associated to insects like frass represented 11.20% of the samples collected. Several collecting methods were explored, based on the possibility of accessing the necessary amount of material causing the less impact. Most of the samples were obtained by manual collection (44.38%), followed by insects breeding (25.73%), light traps (18.80%), different types of nets (10.52%) and other methods (0.16%). In general, collecting methods and practices excluded the use of solvents, mixing different species or life stages in the same bag, which might have introduced undesirable effects in the screening systems for new compounds. Based on the possibility of finding new chemicals in similar samples associated to one arthropod species, the collecting strategy included the generation of several samples from same species, separated according to differences in life stages, collecting sites, ecosystems, seasons, feeding materials or behavioral aspects. This strategy allowed the generation a larger number of samples submitted to bioassays in different areas of pharmaceutical research.Desde 1994 hasta 1997, 1800 muestras de artrópodoscorrespondientes a 642 especies distribuidas en 21 órdenes y 95 familias fueron recolectadas en 21 localidades protegidas del Área de Conservación Guanacaste, para ser estudiadas como fuente potencial de nuevos medicamentos. Las localidades con más recolectas fueron Santa María (231 spp.; 421 muestras), Santa Rosa (110 spp.; 172 muestras), Cacao (98 spp.; 203 muestras) y Pitilla (67 spp.; 79 muestras), siendo la mayor cantidad recolectadas durante la estación lluviosa. El 49.72% de las muestras recolectadas correspondió al orden Lepidoptera, 15.75% a Coleoptera, 13.33% a Hymenoptera, 11.43% a Orthoptera, 6.75% a Hemiptera, 3.20% a Homoptera y 7.89% a otros grupos. Además, un 54.26% de las muestras correspondía a individuos adultos, 19.90% a larvas, 11.20% a estiércol, 6.46% a pupas, 6.12% a prepupas, 2.07% a ninfas y 3.74% a otros estadios. Un 44.38% de las muestras se recolectó mediante recolecta manual, seguido por crianza de insectos (25.73%), trampa de luz (18.80%), diferentes tipos de redes (10.52%) y otros métodos (0.16%). La alta diversidad de los trópicos y la gran abundancia de artrópodos hace de este grupo una fuente potencial de productos farmacéuticos. Sin embargo, se debe evitar la recolecta intensiva en la misma localidad durante años consecutivos (sobre todo hembras), minimizar la interferencia en procesos vitales de los organismos y la dinámica de sus poblaciones. Además se debe recolectar la menor cantidad posible de individuos y escoger la época del año adecuada, para lograr el reestablecimiento natural de las poblaciones.National Institute of Health (Fogarty International Center) No. 5U01TW/CA00312, facilitado por el proyecto NSF DEB 9400829 y DEB 9705072, D. H. JanzenUniversidad de Costa Rica, Vicerrectoría de Investigación, proyecto VI 801-96-582.INBioUCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí

Novel Lobophorins Inhibit Oral Cancer Cell Growth and Induce Atf4- and Chop-Dependent Cell Death in Murine Fibroblasts

As part of the International Cooperative Biodiversity Groups (ICBG) Program, we were interested in identifying biologically active unfolded protein response (UPR) inducing compounds from marine microorganisms isolated from Costa Rican biota. With this aim in mind we have now generated more than 33,000 unique prefractionated natural product extracts from marine and terrestrial organisms that have been submitted to the Center of Chemical Genomics (CCG) at the University of Michigan for high throughput screening (HTS). An effective complementary cell-based assay to identify novel modulators of UPR signaling was used for screening extracts. Active fractions were iteratively subjected to reverse-phase HPLC chromatographic analysis, and together with lobophorin A, B, E, and F (1–4), three new lobophorin congeners, designated as CR1 (5), CR2 (6), and CR3 (7) were isolated. Herein, we report that secondary assays revealed that the new lobophorins induced UPR-associated gene expression, inhibited oral squamous cell carcinoma cell growth, and led to UPR-dependent cell death in murine embryonic fibroblast (MEF) cells.International Cooperative Biodiversity Groups/[U01 TW007404]/ICBG/Estados UnidosNational Institutes of Health/[DK042394]/NIH/Estados UnidosNational Institutes of Health/[DK088227]/NIH/Estados UnidosNational Institutes of Health/[HL052173]/NIH/Estados UnidosUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones en Productos Naturales (CIPRONA)UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Químic

A High-Throughput Screen Identifies a New Natural Product with Broad-Spectrum Antibacterial Activity

Due to the inexorable invasion of our hospitals and communities by drug-resistant bacteria, there is a pressing need for novel antibacterial agents. Here we report the development of a sensitive and robust but low-tech and inexpensive high-throughput metabolic screen for novel antibiotics. This screen is based on a colorimetric assay of pH that identifies inhibitors of bacterial sugar fermentation. After validation of the method, we screened over 39,000 crude extracts derived from organisms that grow in the diverse ecosystems of Costa Rica and identified 49 with reproducible antibacterial effects. An extract from an endophytic fungus was further characterized, and this led to the discovery of three novel natural products. One of these, which we named mirandamycin, has broad-spectrum antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Vibrio cholerae, methicillin-resistant Staphylococcus aureus, and Mycobacterium tuberculosis. This demonstrates the power of simple high throughput screens for rapid identification of new antibacterial agents from environmental samples