Estudio preliminar de Isoflavonoides sintéticos como posibles inhibidores del Virus de la Anemia Infecciosa del Salmón (ISAV).

92 p.La anemia infecciosa del salmón (ISA, Infectious Salmon Anaemia) es una enfermedad que afecta principalmente al salmón del atlántico (Salmo salar), la cual puede aparecer con carácter sistémico y letal. Se pueden observar síntomas llamativos como branquias pálidas, exoftalmia (“ojos saltones”) y abdomen distendido, además pueden ocurrir hemorragias internas y petequias abdominales. El agente viral responsable de la enfermedad (ISA), pertenece a la familia Orthomixoviridae, tal como los virus Influenza A, B y C y Thogotovirus, siendo el virus ISA prototipo del nuevo género denominado ISAVIRUS. Dentro de los 8 segmentos que conforman su genoma de RNA de simple hebra de polaridad negativa segmentado, se sabe que el segmento 3 codifica para la nucleoproteína (NP), la cual tiene un importante rol en la transcripción y replicación genómica viral. Siendo Chile el segundo productor de Salmones a nivel mundial, el virus ISA ha generado grandes pérdidas económicas significando una grave amenaza. Las consecuencias en algunos casos, pueden ser imperceptibles, no obstante los casos de brotes severos, pueden llevar al cultivo de salmones hasta un porcentaje de mortalidad acumulado del 90–100%. Debido a que, hasta la fecha no existe tratamiento eficaz contra el virus de la anemia infecciosa del salmón y las vacunas desarrolladas no presentan una protección adecuada, es necesaria la búsqueda de nuevos antivirales, los cuales ayuden a detener este problema, antes de que la industria se vea gravemente afectada. Debido a la similitud estructural con su homólogo viral Influenza A, este último es utilizado como modelo de estudio en este trabajo para el desarrollo de antivirales candidatos para ISAV. Esta tesis describe la búsqueda de compuestos que tengan similitudes estructura/actividad, con compuestos reportados para virus de influenza A, con la finalidad de encontrar aquellos que actúen como inhibidores para ISA en ensayos ex vivo. Los compuestos que se estudiarán provienen de la familia de los isoflavonoides. El interés de estos compuestos radica en sus variadas actividades farmacológicas reportadas, tales como antiinflamatorios, antioxidantes, anti cancerígenos y antivirales entre otros./ABSTRACT: Infectious salmon anemia (ISA) is a disease that mainly affects Atlantic salmon (Salmo salar), which may occur with systemic and lethal character. It can be see dramatic symptoms like pale gills, exophthalmos ("googly eyes ") and distended abdomen, furtherinternal bleeding and abdominal petechiae can occur. The viral agent responsible for the disease, belongs to the Orthomixoviridae family such as Influenza A, B and C and Thogoto virus, being ISA virus the prototype of new genus called Isavirus. Within the 8 genome segments of singlestranded RNA of negative polarity, it is known that segment 3 encodes for the nucleoprotein (NP) , which plays an important role in viral genomic replication and transcription. Being Chile the second largest producer of salmon in the world, the ISA virus has generated huge economic losses signifying a serious threat. The consequences in some cases, may be imperceptible, however cases of severe outbreaks can lead to farmed salmon to a cumulative 90- 100% percentage of mortality. Because, to date there is no effective treatment for ISAV virus and vaccine developed have not adequate protection, it is necessary to search for new antiviral drugs, which help stopthis problem before the industry will be severely affected. Due to the structural similarity to its viral homolog, Influenza A, the latter is used as a study model for developing potential antiviral for ISAV. This thesis describes the search of compounds that have structure / activity similarities with compounds with reported activity for influenza A virus , in order to find those that, in ex vivo assays act as inhibitors for ISA virus. The compound to be studied comes from the isoflavones family. The interest in these compounds lies in their various pharmacological activities reported, such as anti-inflammatory, antioxidant, anticancer and antiviral among others

Worldwide trends in underweight and obesity from 1990 to 2022: a pooled analysis of 3663 population-representative studies with 222 million children, adolescents, and adults

Background Underweight and obesity are associated with adverse health outcomes throughout the life course. We estimated the individual and combined prevalence of underweight or thinness and obesity, and their changes, from 1990 to 2022 for adults and school-aged children and adolescents in 200 countries and territories. Methods We used data from 3663 population-based studies with 222 million participants that measured height and weight in representative samples of the general population. We used a Bayesian hierarchical model to estimate trends in the prevalence of different BMI categories, separately for adults (age ≥20 years) and school-aged children and adolescents (age 5–19 years), from 1990 to 2022 for 200 countries and territories. For adults, we report the individual and combined prevalence of underweight (BMI <18·5 kg/m2) and obesity (BMI ≥30 kg/m2). For schoolaged children and adolescents, we report thinness (BMI <2 SD below the median of the WHO growth reference) and obesity (BMI >2 SD above the median). Findings From 1990 to 2022, the combined prevalence of underweight and obesity in adults decreased in 11 countries (6%) for women and 17 (9%) for men with a posterior probability of at least 0·80 that the observed changes were true decreases. The combined prevalence increased in 162 countries (81%) for women and 140 countries (70%) for men with a posterior probability of at least 0·80. In 2022, the combined prevalence of underweight and obesity was highest in island nations in the Caribbean and Polynesia and Micronesia, and countries in the Middle East and north Africa. Obesity prevalence was higher than underweight with posterior probability of at least 0·80 in 177 countries (89%) for women and 145 (73%) for men in 2022, whereas the converse was true in 16 countries (8%) for women, and 39 (20%) for men. From 1990 to 2022, the combined prevalence of thinness and obesity decreased among girls in five countries (3%) and among boys in 15 countries (8%) with a posterior probability of at least 0·80, and increased among girls in 140 countries (70%) and boys in 137 countries (69%) with a posterior probability of at least 0·80. The countries with highest combined prevalence of thinness and obesity in school-aged children and adolescents in 2022 were in Polynesia and Micronesia and the Caribbean for both sexes, and Chile and Qatar for boys. Combined prevalence was also high in some countries in south Asia, such as India and Pakistan, where thinness remained prevalent despite having declined. In 2022, obesity in school-aged children and adolescents was more prevalent than thinness with a posterior probability of at least 0·80 among girls in 133 countries (67%) and boys in 125 countries (63%), whereas the converse was true in 35 countries (18%) and 42 countries (21%), respectively. In almost all countries for both adults and school-aged children and adolescents, the increases in double burden were driven by increases in obesity, and decreases in double burden by declining underweight or thinness. Interpretation The combined burden of underweight and obesity has increased in most countries, driven by an increase in obesity, while underweight and thinness remain prevalent in south Asia and parts of Africa. A healthy nutrition transition that enhances access to nutritious foods is needed to address the remaining burden of underweight while curbing and reversing the increase in obesit

I Jornada de Aulas Abiertas: Encuentro de Docentes de la Facultad de Ciencias Económicas

La Jornada de Aulas Abiertas quiere ser una oportunidad para que los docentes de la Facultad de Ciencias Económicas nos encontremos en un espacio de reflexión y revisión de nuestras prácticas, distendido, cálido y respetuoso, que nos permita compartir nuestras experiencias cotidianas en las aulas, tanto presenciales como virtuales. Es la posibilidad de conocernos, intercambiar, aprender y contagiarnos de las inquietudes y el entusiasmo que muchos docentes ponen en juego cotidianamente. En el marco de propuestas de enseñanza, se analizaron recursos multimediales, materiales de estudio, aulas virtuales, redes sociales, aplicaciones web, juegos y actividades de evaluación y coevaluación originales; también se abordaron problemáticas y propuestas para favorecer vinculaciones con la práctica profesional. Estas fueron algunas de las cuestiones abordadas y compartidas en las presentaciones de nuestros colegas. Distintas propuestas, pero siempre con el propósito de favorecer las oportunidades de aprendizaje de nuestros estudiantes. Esta publicación pretende ampliar el alcance de esta actividad. Es una invitación para que los y las docentes que participaron puedan revisar nuevamente aquellas actividades que les parecieron valiosas, o las que no pudieron presenciar. Y para aquellos/as que no tuvieron la posibilidad de estar presentes, puedan descubrir cuánto podemos hacer para que nuestros estudiantes aprendan más y mejor, y se animen a iniciar sus propios recorridos. Esperamos repetir este evento para seguir aprendiendo de las iniciativas de los/las docentes de nuestra Facultad, poder hablar de lo que nos preocupa y nos enorgullece, en particular de las propuestas que desarrollamos en el aula para favorecer la comprensión, promover el entusiasmo, abordar temas complejos y errores frecuentes de nuestros estudiantes. Desde el Área de Formación Docente y Producción Educativa queremos agradecer a las autoridades de nuestra Facultad por acompañarnos en este desafío y a los/las docentes que estuvieron presentes compartiendo sus experiencias.Fil: Sabulsky, Gabriela. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Margaría, Oscar A. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Iturralde, Ivan. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Domenech, Roberto. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Torrico, Julieta. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Estigarribia, Lucrecia. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Gohlke, Guillermo. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Rosenfeld, Valeria. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Montenjano, Franco. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Atienza, Bárbara. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Becerra, Natalia. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Alonso, Micaela. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Tomatis, Karina. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Saunders, Shirley. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: David, María Laura. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Flores, Verónica Andrea. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Heckmann, Gerardo. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Vega, Juan José. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Trucchi, Carlos. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Ferro, Flavia. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Díaz, Cecilia. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Peretto, Claudia. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Racagni, Josefina. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Guardiola, Mariana. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: López, Sonia. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Beltrán, Natacha. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Russo, Paulo. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Sánchez, Pablo. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Rocha Vargas, Marcelo. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Flores, Norma. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Arévalo, Eliana. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Pacheco, Verónica. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Delmonte, Laura. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Stanecka, Nancy. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Caminos, Ana Belén. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Ahumada, María Inés. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Caro, Norma Patricia. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Bravino, Laura. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Giménez, Siria Miriam. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Perona, Eugenia. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Cuttica, Mariela. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: García, Gladys Susana. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Cohen, Natalia. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Tapia, Sebastián. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Erazu, Damián. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Torres, César. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Casini, Rosanna Beatriz. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Rosales, Julio. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Infante, Roberto Adrián. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Ricci, María Beatriz. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Römer, Gabriela. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Goyeneche, Noel. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Marzo, Emanuel. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Olmos, Mariano. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Bottino, Cecilia. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Cacciagiú, Victor. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Scidá, María Florencia. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Guajardo Molina, Vanesa. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Batistella, Silvana del V. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Huanchicay, Silvia. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Jones, Carola. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Cassutti, Marcela Beatriz. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Sánchez, Juan Nicolás. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Arónica, Sandra. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Ortega, Fernando. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Peretti, Florencia. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Tagle, María Mercedes. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Asís, Gloria Susana. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Ortiz Figueroa, Ana María. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Giménez, Miriam Mónica. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Magnano, Cecilia. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina.Fil: Arias, Verónica. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina

¿una aceptación a la diversidad?

Tesis (Magíster en Terapia Ocupacional, mención en Salud Física)Durante décadas pasadas los países han intentado a través de numerosos tratados y legislaciones hacer cumplir los Derechos humanos de todas las personas, entregando apoyos a los que lo requieren, es por esto que en el ámbito de la educación, a modo de entregar todas las herramientas posibles a personas con algún tipo de necesidad educativa especial, se crean los Proyectos de Integración Escolar, los cuales cuentan con un grupo de profesionales de apoyo a la educación, entre los que se encuentran los Terapeutas Ocupacionales. Sin embargo según la legislación Chilena que actualmente rige los Proyectos de Integración Escolar, la participación de la Terapia Ocupacional se ve restringida y a su vez depende de la decisión de cada programa de integración si quiere o no contar con dicho profesional; sin embargo según nuestra perspectiva esto no debería ser así ya que es una profesión que cuenta con las competencias suficientes para generar instancias y prácticas de verdadera integración en el ámbito educativo, ya que valora la diversidad de los sujetos, como a su vez genera conciencia del respeto hacia el otro independiente de las condiciones que cada sujeto presente , lo cual le brinda al sistema escolar un acercamiento a la calidad en la educación , puesto que favorece un mejor desempeño académico y a su vez favorece el hecho de que todas las personas dentro de la comunidad educativa vivan satisfactoriamente la participación escolar

Connectivity of bacterial assemblages along the Loa River in the Atacama Desert, Chile

The Loa River is the only perennial artery that crosses the Atacama Desert in northern Chile. It plays an important role in the ecological and economic development of the most water-stressed region, revealing the impact of the mining industry, which exacerbate regional water shortages for many organisms and ecological processes. Despite this, the river system has remained understudied. To our knowledge, this study provides the first effort to attempt to compare the microbial communities at spatial scale along the Loa River, as well as investigate the physicochemical factors that could modulate this important biological component that still remains largely unexplored. The analysis of the spatial bacterial distribution and their interconnections in the water column and sediment samples from eight sites located in three sections along the river catchment (upper, middle and lower) was conducted using 16S rRNA gene-based Illumina MiSeq sequencing. Among a total of 543 ASVs identified at the family level, over 40.5% were cosmopolitan in the river and distributed within a preference pattern by the sediment substrate with 162 unique ASVs, while only 87 were specific to the column water. Bacterial diversity gradually decreased from the headwaters, where the upper section had the largest number of unique families. Distinct groupings of bacterial communities often associated with anthropogenic disturbance, including Burkholderiaceae and Flavobacteriaceae families were predominant in the less-impacted upstream section. Members of the Arcobacteraceae and Marinomonadaceae were prominent in the agriculturally and mining-impacted middle sector while Rhodobacteraceae and Coxiellaceae were most abundant families in downstream sites. Such shifts in the community structure were also related to the influence of salinity, chlorophyll, dissolved oxygen and redox potential. Network analyses corroborated the strong connectivity and modular structure of bacterial communities across this desert river, shedding light on taxonomic relatedness of co-occurring species and highlighting the need for planning the integral conservation of this basin

Unveiling microbial guilds and symbiotic relationships in Antarctic sponge microbiomes

Abstract Marine sponges host diverse microbial communities. Although we know many of its ecological patterns, a deeper understanding of the polar sponge holobiont is still needed. We combine high-throughput sequencing of ribosomal genes, including the largest taxonomic repertoire of Antarctic sponge species analyzed to date, functional metagenomics, and metagenome-assembled genomes (MAGs). Our findings show that sponges harbor more exclusive bacterial and archaeal communities than seawater, while microbial eukaryotes are mostly shared. Furthermore, bacteria in Antarctic sponge holobionts establish more cooperative interactions than in sponge holobionts from other environments. The bacterial classes that established more positive relations were Bacteroidia, Gamma- and Alphaproteobacteria. Antarctic sponge microbiomes contain microbial guilds that encompass ammonia-oxidizing archaea, ammonia-oxidizing bacteria, nitrite-oxidizing bacteria, and sulfur-oxidizing bacteria. The retrieved MAGs showed a high level of novelty and streamlining signals and belong to the most abundant members of the main microbial guilds in the Antarctic sponge holobiont. Moreover, the genomes of these symbiotic bacteria contain highly abundant functions related to their adaptation to the cold environment, vitamin production, and symbiotic lifestyle, helping the holobiont survive in this extreme environment

Watershed-Induced Limnological and Microbial Status in Two Oligotrophic Andean Lakes Exposed to the Same Climatic Scenario

Laguna Negra and Lo Encañado are two oligotrophic Andean lakes forming part of the system fed by meltwater from distinct glacial tongues of the Echaurren glacier in central Chile, which is in a recession period. The recent increase in temperature and decline in precipitation have led to an increase of glacial meltwater and sediments entering these lakes. Although the lacustrine systems are also hydrogeologically connected, the limnology of the lakes is strongly controlled by the surface processes related to the respective sub-watersheds and hydrology. Watershed characteristics (area and length, slope, lithology, resistance to erosion, among others) affect the chemical and physical characteristics of both lakes (e.g., nutrient concentration and turbidity). We studied physical and chemical variables and performed 16S rRNA amplicon sequencing to determine the specific microbial signature of the lakes. The transparency, temperature, turbidity and concentrations of chlorophyll-a, dissolved organic matter, nutrients and the total number of cells, revealed the different status of both lakes at the time of sampling. The predominant bacterial groups in both lakes were Proteobacteria, Verrucomicrobia, and Bacteroidetes. Interestingly, the contribution of phototrophs was significantly higher in LN compared to LE (13 and 4% respectively) and the major fraction corresponded to Anoxygenic Phototrophs (AP) represented by Chloroflexi, Alpha, and Betaproteobacteria. Multivariate analyses showed that the nutrient levels and the light availability of both lakes, which finally depend on the hydrological characteristics of the respective watersheds, explain the differential community composition/function. The abundance of a diverse photoheterotrophic bacterioplankton community suggests that the ability to utilize solar energy along with organic and inorganic substrates is a key function in these oligotrophic mountain lakes

Image11.TIF

<p>Laguna Negra and Lo Encañado are two oligotrophic Andean lakes forming part of the system fed by meltwater from distinct glacial tongues of the Echaurren glacier in central Chile, which is in a recession period. The recent increase in temperature and decline in precipitation have led to an increase of glacial meltwater and sediments entering these lakes. Although the lacustrine systems are also hydrogeologically connected, the limnology of the lakes is strongly controlled by the surface processes related to the respective sub-watersheds and hydrology. Watershed characteristics (area and length, slope, lithology, resistance to erosion, among others) affect the chemical and physical characteristics of both lakes (e.g., nutrient concentration and turbidity). We studied physical and chemical variables and performed 16S rRNA amplicon sequencing to determine the specific microbial signature of the lakes. The transparency, temperature, turbidity and concentrations of chlorophyll-a, dissolved organic matter, nutrients and the total number of cells, revealed the different status of both lakes at the time of sampling. The predominant bacterial groups in both lakes were Proteobacteria, Verrucomicrobia, and Bacteroidetes. Interestingly, the contribution of phototrophs was significantly higher in LN compared to LE (13 and 4% respectively) and the major fraction corresponded to Anoxygenic Phototrophs (AP) represented by Chloroflexi, Alpha, and Betaproteobacteria. Multivariate analyses showed that the nutrient levels and the light availability of both lakes, which finally depend on the hydrological characteristics of the respective watersheds, explain the differential community composition/function. The abundance of a diverse photoheterotrophic bacterioplankton community suggests that the ability to utilize solar energy along with organic and inorganic substrates is a key function in these oligotrophic mountain lakes.</p

Image9.JPEG

<p>Laguna Negra and Lo Encañado are two oligotrophic Andean lakes forming part of the system fed by meltwater from distinct glacial tongues of the Echaurren glacier in central Chile, which is in a recession period. The recent increase in temperature and decline in precipitation have led to an increase of glacial meltwater and sediments entering these lakes. Although the lacustrine systems are also hydrogeologically connected, the limnology of the lakes is strongly controlled by the surface processes related to the respective sub-watersheds and hydrology. Watershed characteristics (area and length, slope, lithology, resistance to erosion, among others) affect the chemical and physical characteristics of both lakes (e.g., nutrient concentration and turbidity). We studied physical and chemical variables and performed 16S rRNA amplicon sequencing to determine the specific microbial signature of the lakes. The transparency, temperature, turbidity and concentrations of chlorophyll-a, dissolved organic matter, nutrients and the total number of cells, revealed the different status of both lakes at the time of sampling. The predominant bacterial groups in both lakes were Proteobacteria, Verrucomicrobia, and Bacteroidetes. Interestingly, the contribution of phototrophs was significantly higher in LN compared to LE (13 and 4% respectively) and the major fraction corresponded to Anoxygenic Phototrophs (AP) represented by Chloroflexi, Alpha, and Betaproteobacteria. Multivariate analyses showed that the nutrient levels and the light availability of both lakes, which finally depend on the hydrological characteristics of the respective watersheds, explain the differential community composition/function. The abundance of a diverse photoheterotrophic bacterioplankton community suggests that the ability to utilize solar energy along with organic and inorganic substrates is a key function in these oligotrophic mountain lakes.</p

Image5.JPEG

<p>Laguna Negra and Lo Encañado are two oligotrophic Andean lakes forming part of the system fed by meltwater from distinct glacial tongues of the Echaurren glacier in central Chile, which is in a recession period. The recent increase in temperature and decline in precipitation have led to an increase of glacial meltwater and sediments entering these lakes. Although the lacustrine systems are also hydrogeologically connected, the limnology of the lakes is strongly controlled by the surface processes related to the respective sub-watersheds and hydrology. Watershed characteristics (area and length, slope, lithology, resistance to erosion, among others) affect the chemical and physical characteristics of both lakes (e.g., nutrient concentration and turbidity). We studied physical and chemical variables and performed 16S rRNA amplicon sequencing to determine the specific microbial signature of the lakes. The transparency, temperature, turbidity and concentrations of chlorophyll-a, dissolved organic matter, nutrients and the total number of cells, revealed the different status of both lakes at the time of sampling. The predominant bacterial groups in both lakes were Proteobacteria, Verrucomicrobia, and Bacteroidetes. Interestingly, the contribution of phototrophs was significantly higher in LN compared to LE (13 and 4% respectively) and the major fraction corresponded to Anoxygenic Phototrophs (AP) represented by Chloroflexi, Alpha, and Betaproteobacteria. Multivariate analyses showed that the nutrient levels and the light availability of both lakes, which finally depend on the hydrological characteristics of the respective watersheds, explain the differential community composition/function. The abundance of a diverse photoheterotrophic bacterioplankton community suggests that the ability to utilize solar energy along with organic and inorganic substrates is a key function in these oligotrophic mountain lakes.</p