Doctorado en Ciencias - Biología
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Publicación Acceso abierto La variabilidad genética - una herramienta útil en el estudio de poblaciones humanas(Uniandes, 2005) Torres Carvajal, María de la Merced; Groot de Restrepo, HelenaDeterminar la diversidad del ADN mitocondrial en comunidades indígenas colombianas y compararlas con otras poblaciones amerindias, para evaluar hipótesis relativas al poblamiento inicial del territorio americano. Las poblaciones indígenas tienen alto porcentaje de diversidad; presentan los cuatro gurops hapogrupos fundadores reseñados en la literatura y otros halosubgrupos descritos en el estudio. Los resultados sugieren que existía tan solo una onda de emigraciónPublicación Acceso abierto Diversidad de bacillus sphaericus en diferentes hábitat y regiones geográficas(Uniandes, 2006) Dussán Garzón, Jenny; Ayala Serrano, Juan AlfonsoBacillus sphaericus han sido reconocidos en cinco gurpos de homología con base en la hibridación DNA-DNA. Fundamentalmente, las cepas patógenas se han asociado al grupo IIA y las no patógenas a los grupos I, IIB, III, IV, y V. Treinta y dos aislamientos del complejo taxón de diferentes hábitat y regiones geográficas en Colombia y España, fueron evaluados a nivel fonotípico por patrones de perfil peptidoglicano, perfiles proteicos de fracciones celulares y a nivel molecular por polimorfismos por RAPDs, RFLPs, y secuenciación del gen 16S rRNA. Dos cladosfueron determinados por secuenciación parcial de 16S DNA en su relación a su carácter patógeno y ubcación geográfica con una divergencia superior al 4%. Los aislamientos patógenos (6/9) s ubicaron en el clado I relacionado con los grupos de referencia I, IIA, y IV. Los aislamientos de España asociados a Quercus robur Linneo (6/9) mostraron una agrupación en el clado II sin relación con grupos de homologíaPublicación Acceso abierto Diversidad del género Ischnura (Odonata: Coenagrionidae) y su relación con la altitud y orogenia de la cordillera Oriental-Andes colombianos(Uniandes, 2009) Realpe Rebolledo, Emilio Antonio; De Marmels, JürgUno de los factores de la diversidad y distribución de las especies es la temperatura y ésta se relaciona directamente con la latitud y altitud, entre otros factores, por lo tanto afectando también a los odonatos, cuya diversidad disminuye con el aumento de aquellas y encontrándose que su mayor diversidad está en la franja tropical especialmente las regiones biográficas Oriental y Neotropical. La primera parte del estudio muestra el efecto de la latitud sobre la diversidad de la odontofauna en un perfil altitudinal sobre la cordillera Orientalde los Andes Colombianos. En la segunda parte del estudio, se describen e ilustran las dos nueva especies del género Iscnura. Finalmente se aborda un análisis de las relaciones filogenéticas del genero presentes en Colombia, con base en datos morfológicos y marcadores moleculares, usando secuencias de dos genes mitocondriales COI y COII, relacionando además su diversificación con la reciente formación de la cordillera Oriental y su distribución altitudinalPublicación Acceso abierto Cecropia growth pattern periodicity - could a neotropical genus be a good biological clock to estimate the age of disturbed areas?(Uniandes, 2010) Zalamea Zamora, Paul Camilo; Heuret, Patrick; Stevenson Díaz, Pablo RobertoIn the tropics, the surfaces covered with secondary forests are rapidly increasing due to the high deforestation rates. Forest succession is a slow process and continuous data on vegetation change are scare. To study this change, the chronosequence approach has been used but in order to implement it, the knowledge of the secondary forest ages is necessary; however, this information is difficult and/or expensive to gather. Yet, a posteriori reconstruction of individual development in emblematic tropical pioneer trees could be helpful to determine the age of a tree and the moment of individual establishment after a perturbation. In this study, I propose a straightforward and fast method to estimate the age of secondary forests based on the individuals? age estimation of Cecropia, one of the most important pioneer genera of the Neotropics. The objectives of this dissertation were: i) to characterize the developmental pattern of C. sciadophylla, in order to establish a simple protocol to determine the age of C. sciadophylla individuals, ii) to determine how the growth pattern of C. sciadophylla, varies the year and to characterize the stability of this pattern across the species distribution range, iii) to determine the flowering frequencies of Cecropia species and to identify the relationship between flowering events and climate secondary forests in the Neotropics. I found a high annual periodicity in flowering and branching processes, and an alternation of long and short nodes in C. sciadophylla populations. Also, I found that Cecropia inferred ages were highly correlated with real perturbation ages in all cases (i. e. slash and burn agricultural sites, a forestry road, and mining sites. In addition, I propose 21 Cecropia species that show annual flowering patterns and that are distributed over the geographical range of the genus, as potential chronometer species. For the first time it is shown that Cecropia genus is a promising and very precise tool for dating disturbances and studying secondary forest dynamics in the NeotropicsPublicación Acceso abierto Dihydroorotate dehydrogenase of Toxoplasma gondii - kinetic characterization and intracellular localization(Uniandes, 2010) Hortua Triana, Miryam Andrea; Zimmermann, Barbara HannaThe pyrimidine biosynthesis patway in the protozoan pathogen Toxoplosma gondii is essenial for parasite growth during infection. To investigate the properties of Dihydroorotate dehydrogenase (TgDHOD. TgDHOD exhibited a specific activity of 83.8 U/mg, a kcat of 89.2 sec-1 ± 1.5. a Km = 60.3 ±0.002 æM for L-dihydroorotate, and a Km = 28.9 æM ± 1.8 for decylubiquinone (QD). Quinones lacking or having short isoprenoid side chains yielded lower kcats and higher Kms than QD. As expected, fumarate was a poor electron acceptor for this family 2 DHOD. The determined for Redoxal and A77-1726 were 253.3 æM ± 13.3 and 91.2 æM ±2.2, respectively. The enzyme was not significantly affected by brequinar or TTFA, known inhibitors of human DHOD, or by atovaquone. TgDHOD exhibits a 157 ? residue N-terminal extension, consistent with potential organellar targeting, but bioinformatic analysis failed to reveal a consensus subcellular destination, Preliminary inmunolocalization studies of TgDHOD performed in intra- and extracellular parasites treated with the polyclonal antibodies raised against purified recombinant TgDHOD exhibited fluorescence that appeared to colocalize with the apicoplast in fluorescence was observed in -10% of mitochondria stained with Mitotracker Red in extracellular parasites. These findings suggest that TgDHOD is associated with both the apicoplast and mitochondrion, making it a member of a growing list of a metabolic enzymes that are dual targeted in T. gondiiPublicación Acceso abierto Tamizaje selectivo en Colombia para desordenes del metabolismo lisosomal(Uniandes, 2013) Uribe Ardila, Jesús Alfredo; Zimmermann, Barbara Hanna; Giugni, Gino; Burin, Maira Graeff; Guhl Nannetti, FelipeLos Errores Innatos del Metabolismo involucran un grupo de enfermedades monogénicas de herencia autosómica recesiva en su mayoría, que consisten en la alteración de un gen que modifica la función de una proteína, que en la mayoría de los casos es una enzima, lo que genera un bloqueo en los procesos normales del metabolismo, dando origen a los hallazgos bioquímicos y clínicos característicos de las diferentes enfermedades metabólicas. En Colombia los desórdenes hereditarios del metabolismo y muy especialmente las alteraciones en el ámbito lisosomal constituyen un grupo de enfermedades no prioritarias y casi desconocidas para los servicios de salud existentes, a tal punto que son consideradas enfermedades raras aspecto que lleva al subdiagnóstico y al manejo errado de pacientes potencialmente tratables, que terminan siguiendo un grave deterioro ó en el mejor de los casos con secuelas irreversibles a nivel físico y mental. Bajo esta perspectiva, el desarrollo de nuevas metodologías de aproximación diagnóstica en nuestro medio, es parte de todo el engranaje que pretende ofrecer a las familias afectadas por estos desordenes la posibilidad de una definición clínica y en lo posible un tratamiento. Pretende entonces el presente trabajo de investigación, ofrecer las herramientas diagnósticas y valores de referencia para Biomarcadores enzimáticos y las enzimas directamente implicadas, usando sangre recolectada en papel filtro, una condición que facilita la remisión de muestras y permite mayor cobertura en el estudio de pacientes posiblemente afectados por estas alteraciones genéticas. Los hallazgos del presente estudio ofrecerán entonces a la comunidad médica valores de referencia en población control colombiana para Alfa-Galactosidasa A, Ifa Glucosidasa, Alfa-L-iduronidasa, Arilsulfatasa B, Betagalactosidasa, Beta- lucosidasa, Hexosaminidasa Total, Iduronato Sulfatasa y Quitotriosidasa, así como también el comportamiento enzimático de individuos afectados por la Iteración hereditaria de dichas proteínas relacionadas respectivamente a las siguientes enfermedades: Enfermedad de Fabry, Enfermedad de Pompe, Síndrome de Hurler, Síndrome de Maroteaux-lamy, Gangliosidosis GMI, Enfermedad de Gaucher, Enfermedad de Sandoff Mucolipidosis y Síndrome de HunterPublicación Acceso abierto Asociación del antígeno de histocompatibilidad HLA-B15 y espondiloartritis, su influencia en la presentación clínica y pronóstico en la cohorte de pacientes del Hospital Militar Central(Uniandes, 2013) Santos Granados, Ana María; Londoño Patiño, John Dario; Jaramillo Henao, Carlos AlbertoLas Espondiloartritis (SpA), llamadas artritis seronegativas, son un grupo frecuente de enfermedades reumáticas que afectan a personas jóvenes, especialmente hombres menores de 45 años, generando una importante discapacidad y alteración de la calidad de vida producto de la afección de las articulaciones de la columna vertebral, especialmente el segmento lumbar y sacro, al igual que en las articulaciones de los miembros inferiores. Tradicionalmente en este grupo de enfermedades se ha identificado e investigado la forma más severa de presentación clínica llamada Espondilitis Anquilosante (AS), caracterizada por la formación de puentes óseos entre la vertebras que generan la imagen radiológica de ?columna en caña de bambú? y la presencia del alelo HLA-B27 en más del 90% de los enfermos. Esta forma es la más frecuente presentación clínica en población blanca de origen anglosajón. En nuestro medio la AS es menor al 40% de todas las SpA, como ha sido ya reportado en la cohorte del Hospital Militar. Más del 60% de los enfermos Colombianos corresponden a formas no definidas de enfermedad (uSpA), llamadas así por el hecho de presentar todo el conjunto de signos y de síntomas, pero que no pueden ser clasificadas como AS por la ausencia de compromiso radiológico ?anquilótico? a nivel de la columna vertebral. La asociación errónea de las SpA con estados severos de enfermedad representados por ?anquilosis? ha limitado la posibilidad de establecer un diagnóstico adecuado en los pacientes con formas en estadios tempranos o con enfermedad leve plenamente establecida. Muchos pacientes son mal diagnosticados como lumbago común, hernias de disco, espondilo artrosis de columna o fibromialgia. Un detenido análisis clínico podría superar esta barrera diagnostica en la mayoría de los casos. Existe información que permite suponer que al menos en poblaciones mestizas latinoamericanas las formas uSpA, conformarían una categoría definida de enfermedad, con características propias en lo relacionado con una edad de inicio más tardía y el mejor pronostico en el tiempo. La ausencia del B27 y la presencia del B15, podría explicar este comportamiento. De la misma forma el establecer una posible relación entre la enfermedad y subtipo específico de B15 daría un sentido biológico a la relación y abriría un campo de investigación en procura de mejor información relacionada con la etiología de la enfermedad. Por tal motivo se estudió el polimorfismo del HLA-B15 en las Espondiloartritis de los pacientes atendidos en el Servicio de Reumatología del Hospital Militar CentralPublicación Acceso abierto Speciation, alpha diversity and extinction in neotropical ectotherms :effects of paleobiogeographic and climatic processes(Uniandes, 2014) Pinto Sánchez, Nelsy Rocío; Crawford, Andrew Jackson; Calderón Espinosa, Martha Lucía; Sánchez Muñoz, Juan Armando; Carnaval, Ana"In chapter 1 we presented a case of study, the Neotropical skinks, which are difficult to identify and classify due to their conservative morphology (Miralles and Carranza, 2010). The continental populations of Mabuya distributed in Colombia have been assigned to three species: M. falconensis, M. nigropunctata, and M. mabouya. The name M. mabouya was subsequently restricted to the island nation of Dominica in the Lesser Antilles, leaving uncertain the taxonomic identity of continental populations previously assigned to this species (Miralles, 2005). To solve this problem we conducted molecular phylogenetic inference based on mitochondrial and nuclear DNA markers, combining new and previously published data. To evaluate species boundaries we employed a general mixed Yule-coalescent (GMYC) model applied to the mitochondrial data set. Our geographic sampling was especially dense in the northern Andes and Lowlands of Colombia, a central region of the distribution of this genus. Our results suggest that the diversity of Mabuya within Colombia is higher than previously recognized, and includes lineages from Central America and eastern and southern South America. Finally, we conclude that Mabuya sensu stricto should be regarded as a single, monophyletic genus, widely distributed through the Americas. In chapter 2 we were interested in evaluating whether local communities within the Neotropics are 'saturated' , or could they in theory receive even more species? We used a megadiverse group of frogs, the 'terrarana', and use a newly developed biogeographic approach to test the saturation of communities. This study used the Great American Biotic Interchange as a natural experiment. When the isthmus closed species from South America migrated to Central America and vice versa. If the concept of saturation applies, the communities that received colonists from another continent should not experience an increase in diversity (Harrison and Comell, 2008)... In chapter 3 we present the first extinction risk estimate for a tropical species based on ecophysiology. We used two species of Mabuya lizard, one distributed on the mainland and the Other one distributed in Providencia and Santa Catalina Islands. Using physiological data we estimate local extinction risk under predicted climate change within their current geographical distribution. Our study underscores the importance of estimating extinction risk of endemic species in a phylogenetic context, and using an ecophysiological model. Also, we found that a widespread species better captures the variation in potential thermal environments."Publicación Acceso abierto Expression analysis of MicroRNAs in pathological contexts(Uniandes, 2014) Romero Prieto, Martha Liliana; Torres Carvajal, María de la Merced; Janin, Anne; Leboeuf, Christophe; Fend, Falko; Mendivil Anaya, Carlos OlimpoPublicación Acceso abierto Antigenicity of peptides from the protein ROP18, a virulence factor in Toxoplasma gondii(Uniandes, 2014) Primrose, Débora Marina; Zimmermann, Barbara Hanna; Nielsen, Niels Norby; González, John Mario; Tekiel, Valeria"Toxoplasma gondii is one of the most widespread obligate intracellular pathogen within the phylum Apicomplexa, affecting nearly one third of the world population (Pappas et al., 2009). This protozoan parasite can infect almost all warm-blooded animals and is the causing agent of toxoplasmosis (Boothroyd JC. & Grigg ME., 2002). Toxoplasmosis is generally clinically asymptomatic in healthy individuals but may cause severe complications in immunocompromised patients. If infection occurs during pregnancy, the parasite can cross the placental barrier and cause severe damage to the foetus (Jacobs D. et al., 1999). T. gondii has been classified into three distinct strains according to the symptoms in murine models. Type I strain causes lethal infection in all strains of mice; Type II is much less virulent while Type III strain is practically avirulent (Chunlei S. et al., 2002). There has been great interest in determining whether different strains of T. gondii are associated with different clinical outcomes of the disease or infection in specific groups of patients (Boothroyd JC. & Grigg ME., 2002; Sibley D. et al., 1995). The majority of human infections that have been studied in North America and Europe are caused by Type II strains, wich are also common in agricultural animals from these regions. Research done in Colombia has shown mainly Type I strains of T. gondii. Mice act as intermediate hosts of T. gondii and play an important role in its persistence and propagation. (Murphy RG. et al., 2008). Defining the population structure of T.gondii from new regions has important implications for transmission, immunogenicity and pathogenesis of toxoplasmosis (Sibley D. et al., 2009)..."Publicación Acceso abierto Effects of the precipitation regimen and spatial scale on the invertebrate communities and ecosystem processes in phytotelmata(Uniandes, 2015) Ospina Bautista, María Fabiola; Realpe Rebolledo, Emilio Antonio; Molina Escobar, Jorge Alberto; Srivastava, Diane; Valenzuela, LucianoUnderstanding the factors that drive community stmcture and ecosystem processes are a relevant goal in ecology. One factor is environmental heterogeneity that alters communities through changes in habitat and available resource for species; however, it is unclear if those effects can change according to the spatial scale. Another factor is climate change, which affects community composition and ecosystem functionality through the loss of particular predator species; although, it is unknown if rainfall variability can alter the community and energy and nutrient flux in temporal ecosystems, such as ponds or phytotelmata. We used the community within two phytotelmata, ecological model system in order to assess effect regime on communities and ecosystem processes. bromeliads and tree holes, as an of spatial scale and hydrological regime on communities and ecosystem processes. First, we studied the invertebrate community associated to Guzmania multiflora (André) André ex Mez. (Bromeliaceae) and their biological traits. We assessed the relation between biological traits and habitat complexity and resource availability. We found that habitat complexity not only alters the taxonomical diversity of invertebrates in bromeliads but also their functional diversity tlnough changes in the abundance and richness of biological traits. In this regard, biological traits provide an approach to ecosystem processes and invertebrate adaptations to environmental conditions. Second, we investigated the effects of spatial scale dependence of habitat and detritus on community and decomposition. We found that species turnover of invertebrates associated with free holes depended on a spatial scale and that there was a scale-dependent effect of habitat and litter on the community and litter decomposition. Third, we assessed the relationship between the amount and frequency of precipitation and bromeliad community and functioning. We found that the magnitude of precipitation rather than rainfall frequency affected invertebrate communities, decomposition, and primary productivity. Finally, we analyzed the energy and nitrogen flux in a bromeliad invertebrate food web and its interaction with the loss of an intraguild predator. We found that the interaction between shifts in the amount of precipitation and the presence/absence of the predator altered the energy and nitrogen flow in the bromeliad food webPublicación Acceso abierto Deciphering the role of cytidine triphosphate synthase (TgCTP) in the parasite Toxoplasma gondii(Uniandes, 2015) Narváez Ortiz, Heidy Yohana; Zimmermann, Barbara Hanna; Liu, Ji-Long; Guhl Nannetti, FelipeToxoplasmosis is caused by the intracellular obligate parasite Toxoplasma gondii. The current treatments against toxoplasmosis display adverse reactions in many patients, thus, it is important to seek new targets for drug design. Cytidine triphosphate synthase (CTP synthase, EC 6.3.4.2) catalyzes the production of CTP from UTP, the final step in the production of cytidine nucleotides, and the first step in the formation of phospholipid intermediates. CTP synthases also play structural roles associated with maintaining cell shape in organisms such as Caulobacter crescentus. In most other organisms, including mammalian cells, the structural roles are unknown. We have identified and characterized the CTP synthase from T. gondii (TgCTP). Complementation of a lethal double mutant in S. cerevisiae by TgCTP was assessed using a plasmid shuffling approach. TgCTP permitted growth of S. cerevisiae on selective medium, indicating that the parasite protein was capable of substituting for the yeast proteins in vivo. We have also expressed and purified recombinant full-length and truncated his-tagged TgCTP proteins from Escherichia coli. Both TgCTP recombinant proteins were active and kinetic parameters were determinedPublicación Acceso abierto Phage therapy - opportunities and challenges for its development in Colombia(Uniandes, 2016) Holguín Moreno, Angela Victoria; Clockie, Martha; Vives Flórez, Martha Josefina; Reyes Muñoz, Alejandro"Based on the challenges and opportunities we identified for phage therapy, this research aims to point out and narrow the obstacles and take advantage of the open doors to bring phage therapy to Colombia. In this sense, this work is divided into seven chapters that address a group of these challenges and opportunities using different bacteria as models. The first chapter presents the state of the art at the moment of initiating the thesis. By reviewing the literature, we recognized the historical aspects of phage therapy, what was the actual development in the world, in Latin America and in Colombia. This review process allowed the identification of the main challenges and opportunities for the phage therapy in Colombia. The second chapter summarizes the techniques necessary to work with phages. This knowledge and expertise were acquired using a Pseudomonas syringae pv. actinidiae model. In this case, bacteriophages were used successfully to control in vitro the plant pathogen causing canker in kiwifruit plantations in New Zealand. Techniques such as isolation, characterization, in vitro testing, Transmission Electron Microscopy, transduction assays, bacterial growth kinetics, cross-resistance assays, were learned and applied. The third chapter is about phage selection for phage therapy, where Pseudomonas aeruginosa was used as a model. Phage isolation, phage characterization, in vitro testing, and in vivo testing, were performed. This was the first practical approach to phage therapy in our lab. We learned the importance of establishing criteria for phage selection for therapy and categorize the characterization techniques according to its relevance for phage therapy. Chapters 4 and 6 present the interaction between different bacteria and their phages, looking for a deeper understanding of the long-term potential use of the phage therapy. The natural interaction between a phage and its host allows the system to evolve in such a way that an initially susceptible bacterial population can develop resistance. Reciprocally, the phage population might regain infectivity by overcoming the resistance barrier, coexisting in a given environment. These dynamics has been described as co-evolution [Buckling and Rainey, 2002]..."IntroducciónPublicación Acceso abierto Elucidation of role of type three effectors from Xanthomonas axonopodis pv. manihotis(Universidad de los Andes, 2016) Medina Culma, César Augusto; Bernal Giraldo, Adriana JimenaEl cultivo de la yuca es uno de los más importantes en los países tropicales, sin embargo este cultivo puede ser afectado por diversas enfermedades fúngicas, bacterianas y virales. El añublo bacteriano de la yuca (CBB por sus siglas en inglés) es considerada la enfermedad bacteriana más importante de la yuca. CBB puede generar importantes pérdidas en los cultivos bajo condiciones climáticas adecuadas. CBB es causado por Xanthomonas axonopodis pv. manihotis (Xam) una bacteria gram negativa la cual posee diferentes factores de virulencia. Los efectores tipo tres (T3Es por sus siglas en inglés) son los factores de virulencia más importantes en otras bacterias fitopatógenas. Este trabajo esta enfocado en determinar la importancia de los T3Es de Xam tomando diferentes aproximaciones. En la primera parte del trabajo se encontró el papel que juegan diferentes T3S en virulencia y en la inmunidad vegetal a través de la generación de cepas mutantes en los T3Es y mediante el uso de sistemas heterólogos que permiten identificar el papel de los T3Es en inmunidad vegetal...Publicación Acceso abierto Tropical frogs as a model system to understand host-pathogen-microbiota interactions(Uniandes, 2016) Flechas Hernández, Sandra Victoria; Woodhams, Douglas C; Bosch, Jaime; Amézquita Torres, Adolfo; Vives Flórez, Martha JosefinaIn my thesis, I undertook a broad survey of Bd in wild amphibian populations using non-invasive molecular techniques, and using natural history traits of the host along with spatial climatic parameters. I found that Bd is geographically and taxonomically widely distributed, and its presence is best explained by environmental parameters related to temperature and precipitation. Since Bd was also detected in Lowland species of the threatened genus Atelopus, I examined whether the species tested positive for Bd harbor cutaneous symbiotic bacteria capable of inhibiting Bd growth, allowing them to survive. Atelopus aff. elegans was the only species that tested positive for Bd, and holds the skin bacteria with the strongest anti-Bd action. This suggests that bacterial communities may have resulted from natural selection represented by Bd infection. In order to evaluate whether Bd can be considered as a potential tln. eat for Atelopus species, I also assessed Bd prevalence and infection intensity by examining live animals during contemporary field surveys and archived museum specimens. My results showed a decrease in abundance of A. spurrelli suggesting that Bd may have contributed to the apparent decline. In contrast, A. aff elegans remain stable despite the presence of the pathogen fltting an enzootic pattem ofhost/pathogen dynamic. I also evaluated the impact of captivity on the beneficial skin-associated bacterial community. Currently, the only method that has been proposed as an effective way to avoid the extinction of amphibian species is the establishment of captive assurance colonies. Therefore it is imperative to understand and evaluate how captivity could affect the disease dynamics and outcomes. Interestingly, I found that frogs in captivity still harbor bacteria with anti-Bd activity suggesting that captivity programs do not necessarily change bacterial communities of the toad skin in a way that impedes Bd growth control. Lastly, using as a study model two sympatric species of Andean frogs, Dendropsophus labialis and Rheobates palmatus, I provided key information on how microbial pathogen interactions differ across life stages, and how changes in bacterial community composition may affect the response to Bd infection. This thesis highlights the importance of using holistic approaches to better understand disease outcomes in diverse frog species and environments, and informs of possible mitigation efforts that can be implemented in the near future to help control and reduce Bd outbreaksPublicación Acceso abierto Aportes genéticos para el entendimiento de la organización social de la comunidad muisca Tibanica (Soacha, Cundinamarca)(Uniandes, 2016) Pérez Sepúlveda, Luz Adriana; Groot de Restrepo, Helena; Crawford, Andrew Jackson; Porras, Gloria Liliana; Langebaek Rueda, Carl HenrikEn la presente investigación se utilizan herramientas de la genética para responder preguntas sobre la organización social de la población muisca Tardía, anterior al periodo de la conquista. El estudio demuestra el valor de análisis genéticos para controvertir ideas avanzadas desde la arqueología y el estudio de crónicas del Período Colonial. La información de esta investigación proviene del sitio arqueológico Tibanica ubicado en el sur de la Sabana de Bogotá, más exactamente en el municipio de Soacha. El trabajo, realizado en conjunto entre el Departamento de Antropología y el Laboratorio de Genética Humana permitió el desarrollo de uno de los proyectos más ambiciosos, desde el punto de vista de la genética prehispánica, dada la cantidad de individuos científicamente excavados. Este proyecto, además de ayudar a responder preguntas formuladas por arqueólogos, ha involucrado una etapa de estandarización de metodologías y de adecuación de espacios que ha llevado al desarrollo de protocolos aptos para la generación de resultados provenientes de ADN antiguo autentico. También aporta, aunque no es su interés central, información que será importante para la reconstrucción del poblamiento indígena del norte de Suramérica. Específicamente, logró tipificar información genética proveniente de las regiones hipervariables I y II del ADN mitocondrial de individuos enterrados con ajuares ricos, con el fin de determinar si el acceso a esa clase de ajuares estaba restringido a miembros de unos pocos linajes maternos, como han propuesto algunos arqueólogosPublicación Acceso abierto Risk assessment in occupationally exposed populations to toxic agents - determination of genetic and epigenetic effects under oxidative stress conditions(Uniandes, 2016) Narváez Noguera, Diana María; Bolognesi, Claudia; Uribe Ardila, Jesus Alfredo; Groot De Restrepo, Helena"The research question of this thesis was: if DNA effects induced by OS associated with occupational exposure, could be used as biomarkers for early detection of high cost labor associated diseases. To address this question, the aim of the study was to characterize genetic and epigenetic effects of occupational exposure to coal dust and to Hg in mining activities. The data collected Will contribute to draw a perspective of contamination levels and to size effects of exposure. These results may help to establish health regulations focused on prevention, and to justify environmental policies in order to reduce the impact of exposure on Colombian miners' health..."-- Tomado de la introducciónPublicación Acceso abierto Evaluating the pyrimidine metabolism in the plant pathogen Phytophthora infestans as a target to control the late blight disease(Uniandes, 2016) Garavito Diago, Manuel Fernando; Zimmermann, Barbara Hanna; Mhölmann, Torsten; Restrepo Restrepo, Silvia; Reyes Muñoz, AlejandroThis project studied pyrimidine metabolism in Phytophthora infestans, not only because it has been positioned as a model organism to study oomycetes, it can be grown m vitro and in vivo in potatoes and tomatoes (and some Other hosts), it has a sequenced genome and there are available methods for its genetic transformation that allow silencing genes or to work with reporters proteins, but also, due to its historical importance in human migrations, its aggressiveness in the field, the great economic importance of crops affected (potato and tomato) and its increasingly frequent resistance to agrochemicals. The results of the Ph.D. project are presented and discussed in three separate chaptersPublicación Acceso abierto Visual and acoustic communication signals in birds - taxonomy, evolution and transfer between signals mediated by sensory drive(Uniandes, 2016) Laverde Rodríguez, Oscar Alberto; Ryan, Michael; Slabbekoorn, Hans; Cadena Ordónez, Carlos Daniel; Molina Escobar, Jorge AlbertoThe evolution of communication signals is a central, integrative topic in evolutionary biology. In this dissertation, I propose that achieving a comprehensive understanding of the evolution of such signals requires not only considering different theories in isolation (i.e. the transfer and sensory drive hypotheses), but also possible interactions between theories and disciplines. For example, the negative association between communication signals observed by Darwin might be strongly determined by adaptation for communication to different habitats: Each habitat has its own features affecting the efficacy of communication, and animals should evolve strategies to optimize signal salience in the face of resolving potential tradeoffs. Based on this overall framework we tested hypothesis about the evolution of and relationships between acoustic and visual signals in relation to habitat features. I used birds as a model system, but the approach and conclusions likely apply to other animals using both acoustic and signals for communication. Specifically, this work focused on three different study systems which allowed me to approach the relationships between types of signals from different perspectives: (1) two species complexes in the tinamou family (Tinamidae) differing in patterns of variation in plumage and vocalizations, (2) a widely distributed family of passerine birds with species exhibiting different communication strategies and occurring in contrasting habitats (i.e the New World warblers, Parulidae), and (3) an assemblage of multiple species coexisting locally in tropical montane forest site. Additionally, i explored the use and relevance of information contained in sound collections for studies on the ecology and evolution of animal communicationPublicación Acceso abierto Systematics and phylogeography of southern ocean deep-sea octocorals(Universidad de los Andes, 2016) Dueñas Montalvo, Luisa Fernanda; Wilke, Thomas; Crawford, Andrew Jackson; 335316; Lessios, Harilaos; Realpe Rebolledo, Emilio Antonio; Sánchez Muñoz, Juan ArmandoOctocorals are very diverse marine organisms that inhabit virtually every marine ecosystem, therefore are widely distributed around the globe. The origin of their huge diversity has been questioned for several decades, however very few studies have addressed this issue until now. This doctoral thesis explored the systematic relationships of octocoral deep-sea fauna distributed in Antarctic and Sub-Antarctic regions, and evaluated the role of the Antarctic Circumpolar Current (ACC) as a driving force for the diversification of octocoral deep-sea populations. It also assessed the evolution of four octocoral traits and the role of these traits on diversification rate shift. To answer the previous questions we used different approaches and methods that included phylogenetics, molecular dating, character evolution, phylogeography and population genetics. Here, we present the first assessment of phylogeographical patterns and the role of the ACC in the genetic connectivity for two deep-sea octocorals in the Pacific and Southern Ocean: Tokoprymno maia, which is a brooding octocoral, and Hemicorallium imperiale, which is a broadcast spawner. We also explored the systematic relationships of the deep-sea bamboo corals of the subfamily Keratoisidinae, and described two new species Keratoisis magnifica and Keratoisis peara. Finally, we inferred the most comprehensive time-calibrated phylogeny of all Octocorallia to date. We estimated the time of origin of this group around the Triassic, where he first octocorals appear to have been soft-bodied colonies, azooxanthellate, deep-water and cold-water organism. The study of marine benthic organisms has increased in the last decade, particularly for deep-sea fauna. This thesis has contributed greatly in the general knowledge of diversity patterns, temporal diversification processes, and population dynamics for Octocorallia. Our contribution has also laid a basis for further evolutionary studies on these incredible diverse organisms.