Repositorio Digital Ikiam (Univ. Regional Amazónica)
Not a member yet
850 research outputs found
Sort by
Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates
Get PDFAim: To investigate the geographic patterns and ecological correlates in the geo-graphic distribution of the most common tree dispersal modes in Amazonia (endozoo-chory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for con-structing zoochorous fruits (resource-availability hypothesis).Time period: Tree-inventory plots established between 1934 and 2019.Major taxa studied: Trees with a diameter at breast height (DBH) ≥ 9.55 cm.Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield.Methods: We assigned dispersal modes to a total of 5433 species and morphospe-cies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and per-manently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes.Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests.Main conclusions: The disperser-availability hypothesis was well supported for abi-otic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the propor-tional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling re-cruitment across forest type
Diversidad de macroinvertebrados acuáticos y calidad del agua a lo largo de un gradiente antrópico en la cuenca alta del Río Napo
Get PDFVarios afluentes de la cuenca del río Napo son fuertemente impactados por minería
aurífera, acuicultura-agricultura intensiva, y descarga de aguas residuales. Algunos de
ellos no han sido estudiados y carecen de información sobre calidad ecológica del agua
y biodiversidad, limitando las acciones para la gestión del agua. Por tanto, los objetivos
de investigación fueron (1) evaluar la calidad del agua en algunos tributarios sobre un
gradiente antrópico, (2) relacionar la estructura de los macroinvertebrados con varios
parámetros físico-químicos, y (3) determinar los impactos sobre la comunidad de
macroinvertebrados y los ecosistemas acuáticos. Entonces se recolectaron datos
fisicoquímicos y de macroinvertebrados en 36 sitios durante las épocas secas de 2020-
2021; se evaluaron las características de la comunidad de macroinvertebrados y la
calidad del agua. Los resultados mostraron impactos significativos sobre los
ecosistemas acuáticos en sitios antrópicos, que comparados con FT muestran baja
diversidad y calidad. La calidad del agua osciló entre moderada y muy mala para los
índices AAMBI y BMWP-Col, clasificando los sitios como FT>CA>WD>GM; mientras
que para CCE-A y CCE-B varió entre buena y pobre, categorizándose FT>CA>GM>WD.
El análisis multivariado indicó que una mayor calidad de agua con pH y DO% altos
caracteriza a FT; mientras TDS, turbidez y temperatura altos se relacionaron con GM.
WD y CA no presentaron relaciones notables con los parámetros descritos. Con esta
información, las partes interesadas tienen una línea base defendible para reducir el
estrés en los afluentes, así como para desarrollar o mejorar las herramientas de gestión
ambiental basadas en biomonitoreo
Picturins and Pictuseptins, two novel antimicrobial peptide families from the skin secretions of the Chachi treefrog, Boana picturata
Get PDFThe Imbabura treefrog (Boana picturata) is an underexplored source of bioactive peptides. The combination of molecular cloning and mass spectrometry allowed us to identify three new peptide families, named "Picturins" (PTR), "Pictuseptins" (PTS), and "Boanins" (BNS). PTR is composed of three 25-mer peptides, characterized by the N-terminal sequence: GVFKDALKQ and the C-terminal sequence: AANALKPK. The sequences of PTR-1, -2 and - 3 are highly conserved only showing two divergent sites: (L/F) in position 10 and (K/Q) in position 17. PTS gathers six peptides. PTS -1, -2 and - 4 have 22 amino acid residues in length, while PTS -3, -5 and - 6 are composed of 26 residues. Whereas BNS are four 28-37 mer peptides, showing two conserved regions: the N-terminal sequence FLGAL and the C-terminal sequence KALNP. PTR-1 to 3 and PTS -1 to -3 were chemically synthetized and their antimicrobial and haemolytic activity was assessed. PTR displayed moderate activity against Escherichia coli (MIC 24.80 to 48.95 μM), while PTS showed a broad antimicrobial and antifungal effect. PTS-1 was the most active peptide against E. coli (6.8 μM) followed by PTS-3 (11.7 μM) and PTS-2 (14.24 μM). These peptides also showed low haemolytic activity, pointing to a favorable selectivity. Overall, new unique non-hemolytic and cationic peptide sequences were characterized that could be valuable for the next-generation of anti-infective drugs. Future functional studies should explore the pharmacological potential of Boanins to include them as antimicrobial scaffolds. BIOLOGICAL SIGNIFICANCE: Nature-inspired solutions have shown their importance mainly for the development of the pharmaceutical industry. Frog skin peptides are excellent examples of the biomedical potential of naturally evolved molecules for specific targets, including multi-resistant bacteria. The characterization of new chemical entities from poorly studied skin secretions of Ecuadorian biodiversity, such as B. picturata, represents an unprecedented opportunity to identify candidates to tackle global concerns, for instance, antibiotic resistance
A First Look at the Inhibitory Potential of Urospatha sagittifolia (Araceae) Ethanolic Extract for Bothrops atrox Snakebite Envenomation
Get PDFBothrops atrox snakebites are a relevant problem in the Amazon basin. In this biodiverse region, the ethnomedicinal approach plays an important role as an alternative to antivenom therapy. Urospatha sagittifolia (Araceae) is a plant used for this purpose; however, its neutralizing properties have not been scientifically accessed. To fill this gap, we investigated the ability of U. sagittifolia to modulate the catalytic activity of Bothrops atrox venom, and their toxic consequences, such as local damage and lethality. The venom profile of B. atrox was assessed by chromatography and electrophoresis. Inhibition of the three main enzymatic and medically important toxins from the venom was evaluated using synthetic substrates and quantified by chromogenic activity assays. Additionally, the neutralization of lethality, hemorrhage and edema were investigated by in vivo assays. The possible interactions between venom proteins and plant molecules were visualized by polyacrylamide gel electrophoresis. Finally, the phytochemical constituents present in the ethanolic extract were determined by qualitative and quantitative analyses. The ethanolic extract reduced the activity of the three main enzymes of venom target, achieving ranges from 19% to 81% of inhibition. Our in vivo venom neuralizations assays showed a significant inhibition of edema (38.72%) and hemorrhage (42.90%). Additionally, lethality was remarkably counteracted. The highest extract ratio evaluated had a 75% survival rate. Our data support the biomedical value of U. sagittifolia as a source of natural enzyme inhibitors able to neutralize catalytically active B. atrox venom toxins and their toxic effects
Microplastics in a tropical Andean Glacier: A transportation process across the Amazon basin?
Get PDFMicroplastic (MPs) contamination is ubiquitous in most terrestrial and aquatic ecosystems. Recently MPs have been reported at high altitudes which indicates that air masses can transport and deposit MPs in the surface snow of high mountain ecosystems, however, whether MPs typification and abundance can be influenced by direction and origin of air masses still remains an open question. Here we present the first report of MPs above 5000 m a.s.l from surface snow of a glacier in the tropical Andes. We collected surface snow along an elevational gradient, from 5000 to 5400 m a.s.l., in the Antisana Glacier, in the northern Andes cordillera of Ecuador to analyze MPs abundance and polymeric identification with the Fourier Transform Infrared (FTIR) and also to hypothesized the possible MPs sources in this remote area by comparing the oxygen and hydrogen stable isotopic ratio composition of the snow samples and by analyzing the wind direction. We observed an average of 131 ± 24 MPs L−1 in our samples. Fibers corresponded to 70% of all MP shapes; FTIR results showed that MPs composition mainly included polyurethane, polyethylene, polyamide, polyester, and high-density polyethylene in surface snow. There were no statistically significant differences of MPs abundance among sampled elevations, and the isotopic ratio composition did not differ among locations. Our results suggest that MP that accumulated in the glacier may be transported from the east, across the Amazonia, by the prevalent eastward air flow. The absence of industrial cities at least 2000 km further east from Antisana, indicates that the remote Andean glaciers could constitute important depositional zones for long-distance transported contaminants
Energy Transition Scenarios for Fossil Fuel Rich Developing Countries under Constraints on Oil Availability: The Case of Ecuador
Get PDFThe aim of this paper is to analyze energy pathways for a fossil fuel rich developing country
towards an energy transition considering national and international oil availability using Ecuador as a
reference. An integrated assessment model has been developed to simulate energy transition scenarios
considering constraints on oil availability at the national and global level. Results show that if current
trends in energy demand and supply persist, energy scarcity would start around 2040 due to depletion
of national oil reserves and restricted access to foreign oil. This would trigger a degrowth in economic
activity in sectors with high dependency on petroleum products. Scenarios with conservative efforts
might partially revert the increasing use of fossil fuels supported by policies for energy efficiency
and substitution of liquid fuels with electricity mainly from renewables. However, energy shortages
would still be foreseeable as well as a decay of the economy. Under a maximum efforts scenario with
an optimistic availability of national oil, a moderate-sustained economic growth could be feasible.
This shows that oil would still play a key role during the transition. Furthermore, ambitious policies
must be implemented in the short term to smooth the effects of displacing oil as energy and income
sourc
Análisis de Sismitas y paleosismología como indicadores de magnitudes de la actividad sísmica de la falla Santa Rosa, en el Piedemonte Amazónico, Ecuador.
Get PDFLa paleosismología en la zona subandina ecuatoriana no ha sido utilizada, a pesar de ser una región ectónicamente activa. En este trabajo se analiza una trinchera al sur de la Falla Porotoyacu, la cual presenta deformaciones en los depósitos sedimentarios. El objetivo de esta investigación es estimar las magnitudes y los eventos de esta falla a través de la paleosismología y la caracterización de sismitas. Los resultados obtenidos del análisis de dos planos de ruptura permitieron identificar dos eventos sísmicos en una de las rupturas, mientras que en la otra se reconoció un solo evento. Estos eventos registraron magnitudes entre 6.22 5. Finalmente, se estima que las rupturas evidenciadas en la trinchera del área de estudio son parte de una Falla principal denominada Porotoyacu, la cual se encuentra a 1.62 km hacia el NE
Partes biológicas y estrategias empleadas en el desarrollo de biosensores para la detección de CADMIO en muestras ambientales
Get PDFLa contaminación por cadmio proviene principalmente de fuentes naturales o antropogénicas. La minería ilegal y la explotación petrolera son dos de las actividades más contaminantes para la región de la Amazonía Ecuatoriana afectando a las comunidades cercanas. Para monitorear este problema se necesita de instrumentos económicos, sencillos, precisos y sensibles, como son los biosensores. Este instrumento compuesto por un sensor biológico, que reconoce un cambio químico o físico, acoplado a un elemento transductor que produce una señal medible en respuesta a la presencia del cadmio. Para obtener biosensores específicos para cadmio se usa la biología sintética, como una herramienta eficiente, que permite la modificación de genes para adquirir las características deseadas. Por lo cual, se realizó una recopilación de las partes biológicas (genes receptores, genes reporteros y chasis) y estrategias usadas en biosensores para la detección de cadmio de los artículos científicos y equipos de la competencia iGEM. Esta recopilación muestra que los genes más empleados como elementos de detección son los genes cadR y cadC, mientras que el gen más utilizado como elemento reportero es la proteína verde fluorescente y la bacteria más empleada como chasis es Escherichia coli. Entre las estrategias más novedosas fueron la creación de un toggle switch, de una puerta lógica AND y la implementación de la maquinaria de transcripción del bacteriófago T7. Con esta información se plantea dos estrategias que podrían mejorar la sensibilidad y selectividad de un biosensor para que sean la base de un sistema alternativo para la detección in situ de cadmio en muestras ambientales locales.Tutora: Fukushima, Ery Odett
Caracterización de la variabilidad interespecífica del veneno de tres serpientes del género Micrurus en Ecuador
Get PDFLas serpientes del género Micrurus, con 85 especies son las principales representantes de la familia Elapidae en América del Sur. Los accidentes ofídicos causados por la mordedura por estas serpientes son poco probables, pero desencadenan un envenenamiento severo caracterizado por la alta neurotoxicidad. El presente trabajo tuvo como objetivo evaluar la variabilidad interespecífica de la composición y abundancia relativa de las toxinas presentes en venenos de serpientes coral. Los venenos de tres especies de serpientes del género Micrurus: M. lemniscatus helleri M. mipartitus y M. multiscutatus de Ecuador fueron analizados por “snake venomics”, una estrategia proteómica para determinar su composición. Las proteínas fueron separadas mediante RP-HPLC y SDS-PAGE, y digeridas con tripsina para su posterior análisis por espectrometría de masas en tándem (MS/MS) y asignación a familias de proteínas. En el veneno de M. lemniscatus helleri se encontraron seis familias de proteínas, donde las fosfolipasas A2 (PLA2) predominaron con 72,13%, mientras que en M. mipartitus, se hallaron cuatro familias de proteínas, donde las toxinas de tres dedos (3FTx) componen el 63,40% del proteoma total. Sin embargo, para M. multiscutatus, no se pudo realizar una buena identificación que determine la predominancia entre los fenotipos PLA2 y 3FTx. El conocimiento de la composición de los venenos de serpientes Micrurus, permitiría racionalizar la reactividad cruzada de los antivenenos poliespecíficos y mejorar su eficiencia para neutralizar los envenenamientos.Tutor: Almeida, José Rafael, d
Dealumination and Characterization of Natural Mordenite-Rich Tuffs
Get PDF: The present study evaluates the feasibility of partially dealuminated natural mordenite as a
catalyst support by studying improvement in its textural properties. This is the first study that reports
the dealumination of natural zeolite-based tuffs from Ecuador. For this purpose, mordenite-rich
tuffs were obtained from deposits close to Guayaquil, Ecuador. The raw material was micronized
in order to increase its surface, and treated with NH4Cl. NH4
+
cation-exchanged samples were
finally reacted with HCl(aq) to complete the dealumination process. The partially dealuminated
samples were characterized using techniques such as XRD, FT-IR, SEM-EDS, and identification of
their textural properties. Dealumination with HCl(aq) increased the Si/Al ratio up to 9 and kept
the crystallographic structure of natural mordenite, as XRD results showed that the structure of
mordenite was not altered after the dealumination process. On the other hand, textural properties
such as surface area and microporosity were improved as compared to natural mordenite. In view of
these results, the feasibility of using natural mordenite as a catalyst support is discussed in this stud