Repositorio Digital Ikiam (Univ. Regional Amazónica)
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Microplastics in rivers and coastal waters of the province of Esmeraldas, Ecuador
Get PDFThis study represents the first assessment of microplastic (MP) contamination in the coastal area of the Esmer aldas Province, Ecuador. MPs were quantified in 14 coastal waters in beaches with different urbanization level
and in 10 rivers. The most abundant MP types were transparent fibres, brown fragments, grey fragments,
transparent fragments, and black fragments, which together represented 84% of the total count. Coastal waters
presented significantly higher quantities of MP than rivers. No difference in microplastic abundance was detected
between beaches with higher and lower urban occupation, nor between beaches facing North or West. Our re sults indicate that MP contamination is widespread, and most likely transported from multiple sources. Our
results can serve as a baseline for future MP monitoring in the are
Lessons from a Single Amino Acid Substitution: Anticancerand Antibacterial Properties of Two PhospholipaseA2-Derived Peptides
No full textThe membrane-active nature of phospholipase A2-derived peptides makes them potentialcandidates for antineoplastic and antibacterial therapies. Two short 13-mer C-terminal fragmentstaken from snake venom Lys49-PLA2toxins (p-AppK and p-Acl), differing by a leucine/phenylalaninesubstitution, were synthesized and their bioactivity was evaluated. Their capacity to interfere withthe survival of Gram-positive and Gram-negative bacteria as well as with solid and liquid tumorswas assessedin vitro. Toxicity to red blood cells was investigated via in silico andin vitrotechniques.The mode of action was mainly studied by molecular dynamics simulations and membrane permeabi-lization assays. Briefly, both peptides have dual activity, i.e., they act against both bacteria, includingmultidrug-resistant strains and tumor cells. All tested bacteria were susceptible to both peptides,Pseudomonas aeruginosabeing the most affected. RAMOS, K562, NB4, and CEM cells were the mainleukemic targets of the peptides. In general, p-Acl showed more significant activity, suggestingthat phenylalanine confers advantages to the antibacterial and antitumor mechanism, particularlyfor osteosarcoma lines (HOS and MG63). Peptide-based treatment increased the uptake of a DNA-intercalating dye by bacteria, suggesting membrane damage. Indeed, p-AppK and p-Acl did notdisrupt erythrocyte membranes, in agreement with in silico predictions. The latter revealed that thepeptides deform the membrane and increase its permeability by facilitating solvent penetration. Thisphenomenon is expected to catalyze the permeation of solutes that otherwise could not cross thehydrophobic membrane core. In conclusion, the present study highlights the role of a single aminoacid substitution present in natural sequences towards the development of dual-action agents. Inother words, dissecting and fine-tuning biomembrane remodeling proteins, such as snake venomphospholipase A2isoforms, is again demonstrated as a valuable source of therapeutic peptides
Transiciones alimentarias: usos de la tierra, plantas y dietas entre los kichwa de Tena, Napo
Get PDFLa alimentación es un elemento indispensable de la existencia humana.
Ella incluye representaciones de los alimentos, técnicas de adquisición y
procesamiento, usos, intercambios comerciales y no comerciales (Suremain
& Katz, 2009; Kuhnlein, 2014). Por lo tanto, los alimentos son objetos
cargados de conocimientos, portadores de historia y de la identidad cultural
de un grupo social (Santilli, 2015; Fischler, 1988). En sí, los alimentos (así
como los artefactos y utensilios culinarios) son elementos materiales del
patrimonio alimentario, colmados de elementos inmateriales tales como las
prácticas, conocimientos y representaciones inmersas en el tejido social de un
grupo determinado (Santilli, 2015: 586). Este patrimonio alimentario es el
resultado de la transmisión intergeneracional y de las relaciones sociales
ETNOBOTÁNICA Y ETNOFARMACOLOGÍA DE Uncaria guianensis EN LA AMAZONÍA: USO DE “UÑA DE GATO” EN LA MEDICINA KICHWA
Get PDFUncaria guianensis es una liana que pertenece a la
familia Rubiaceae, originaria de la región amazónica
[1]. La investigación se realizó en tres comunidades
Kichwa, localizadas en la provincia de Napo,
Amazonía del Ecuador. La planta se reconoce en el
Ecuador con el nombre vernáculo de “uña de gato”
[2]
Morphometric Differentiation and Diet of Engystomops pustulosus (Amphibia: Leptodactylidae) in Three Populations from Colombia
Get PDFThis paper evaluated the intraspecific variation and diet of Engystomops pustulosus in three localities (Colosó, Santa Inés, and El Roble) of the department of Sucre, Colombia. Thirty specimens were collected by locality and the diet composition was determined. We characterized the phenotypic variation by means of skull geometric morphometrics and ten body measures. Finally, the relationship between morphogeometric variables (shape and size) and diet were evaluated. We found significant differences between skull conformation and localities, and between localities and the centroid size. Termites were the most important type of prey, followed by ants and mites. The diet composition did not correlate with the body measures; however, an analysis of Partial Least-Squares showed a correlation between the composition of the diet and skull conformation
Activación ante luz visible del catalizador micro/nano jerárquico Bi7O9I3 y degradación de contaminantes solubles en agua: BFA y RhB
Get PDFLos procesos de oxidación avanzada a partir de fotocatalizadores son una tecnología
prometedora dentro del área de tratamiento de aguas residuales. Entre estos
fotocatalizadores destacan los BiOXs (X= F, Cl, Br y I) debido a su activación ante luz visible
y ausencia de subproductos de desinfección. El desarrollo de estas tecnologías surge a
partir de las deficientes plantas de tratamiento de agua residual convencional (procesos
físicos y químicos) y la contaminación antropogénica de los cuerpos de agua. En el presente
trabajo, tiene como objetivo caracterizar estructural (DRX, MEB, MET y Df) y químicamente
el catalizador Bi7O9I3 y evaluar su eficiencia fotocatalítica ante Bisfenol A (BFA) y Rodamina
B (RhB) con luz visible. El catalizador presenta una estructura micro/nano en formas de
esferas, rectángulos y hexágonos. La degradación de BFA y RhB fue superior al 85% en 180
minutos de irradiación mostrando una mejor actividad que el TiO2. Por otra parte, la
dimensión fractal (Df) del catalizador depositado en vidrio a nano, micro y mili escala
presenta un rango entre 1.7586 a 1.8831, mostrando una relación directa entre Df y el área
de las partículas depositas. Adicionalmente, el empleo de la técnica Layer by Layer (siglas
en inglés) resultó eficiente en la deposición del catalizador sobre membranas cerámicas.
Por lo tanto, el catalizador Bi7O9I3 al ser activo ante luz visible y mostrar acoplamiento en
membranas cerámicas brinda la posibilidad de su aplicabilidad como compuesto
fotocatalítico en el tratamiento de aguas residuales
Caracterización Fitoquímica y elucidación estructural de metabolitos secundarios de Picramnia sp. En la Amazonía Ecuatoriana
Get PDFLas especies del género Picramniase encuentran a lo largo de América tropical,evidenciando una amplia distribución. Además, se han descrito los metabolitossecundarios que presentan algunas de ellas. En la provincia de Napo, ubicadaen la Amazonía ecuatoriana, se encuentra una de las especies de este género,cuyos metabolitos aún no han sido elucidados. En el presente trabajo se esta-bleció como objetivo extraer y aislar metabolitos secundarios de esta planta,así como caracterizarlos mediante técnicas espectroscópicas. Se recolectaronlas partes aéreas de la plantaPicramniasp. en la Reserva Biológica Jatun Sacha.Las hojas secas y molidas fueron maceradas consecutivamente en diferentessolventes, y algunos de los extractos obtenidos fueron particionados y/o purifi-cados por cromatografía en columna flash. Tanto a las hojas secas como a losextractos obtenidos se les realizó pruebas cualitativas para determinar la pre-sencia de los metabolitos de interés. Se comprobó la presencia de antraquino-nas, taninos, terpenoides, fenoles y flavonoides. Finalmente, se identificaronβ-sitosterol y crisofanol en fracciones purificadas, las cuales fueron elucidadasusando una combinación de espectroscopía de RMN 1H, RMN 13C y espectro-metría de masas. Se conoce que ambas moléculas cuentan con diversas activi-dades farmacológicas, dentro de las cuales destaca su actividad antimicrobiana
Multispectral canopy reflectance improves spatial distribution models of Amazonian understory species
Get PDFSpecies distribution models are required for the research and management of biodiversity in the hyperdiverse tropical forests, but reliable and ecologically relevant digital environmental data layers are not always available. We here assess the usefulness of multispectral canopy reflectance (Landsat) relative to climate data in modelling understory plant species distributions in tropical rainforests. We used a large dataset of quantitative fern and lycophyte species inventories across lowland Amazonia as the basis for species distribution modelling (SDM). As predictors, we used CHELSA climatic variables and canopy reflectance values from a recent basin‐wide composite of Landsat TM/ETM+ images both separately and in combination. We also investigated how species accumulate over sites when environmental distances were expressed in terms of climatic or surface reflectance variables. When species accumulation curves were constructed such that differences in Landsat reflectance among the selected plots were maximised, species accumulated faster than when climatic differences were maximised or plots were selected in a random order. Sixty‐nine species were sufficiently frequent for species distribution modelling. For most of them, adequate SDMs were obtained whether the models were based on CHELSA data only, Landsat data only or both combined. Model performance was not influenced by species’ prevalence or abundance. Adding Landsat‐based environmental data layers overall improved the discriminatory capacity of SDMs compared to climate‐only models, especially for soil specialist species. Our results show that canopy surface reflectance obtained by multispectral sensors can provide studies of tropical ecology, as exemplified by SDMs, much higher thematic (taxonomic) detail than is generally assumed. Furthermore, multispectral datasets complement the traditionally used climatic layers in analyses requiring information on environmental site conditions. We demonstrate the utility of freely available, global remote sensing data for biogeographical studies that can aid conservation planning and biodiversity management
Panmixia across elevation in thermally sensitive Andean dung beetles
Get PDFJanzen’s seasonality hypothesis predicts that organisms inhabiting environments with limited climatic
variability will evolve a reduced thermal tolerance breadth compared with organisms experiencing
greater climatic variability. In turn, narrow tolerance breadth may select against dispersal
across strong temperature gradients, such as those found across elevation. This can result in
narrow elevational ranges and generate a pattern of isolation-by-environment, or neutral genetic
differentiation correlated with environmental variables that is independent of geographic distance.
We tested for signatures of isolation-by-environment across elevation using genome-wide SNP data
from five species of Andean dung beetles (subfamily Scarabaeinae) with well-characterized, narrow
thermal physiologies and narrow elevational distributions. Contrary to our expectations, we found
no evidence of population genetic structure associated with elevation and little signal of isolationby-
environment. Further, elevational ranges for four of five species appear to be at equilibrium and
show no evidence of demographic constraints at range limits. Taken together, these results suggest
physiological constraints on dispersal may primarily operate outside of a stable realized niche
Long-Term Monitoring Reveals Population Decline of Spectacled Caimans (Caiman crocodilus) at a Black-Water Lake in Ecuadorian Amazon
Get PDFKnowledge on long-term population trends in crocodilians is essential to assess the effectiveness of conservation areas and to guide sustainable management practices. We studied changes in population size of spectacled (Caiman crocodilus) and black caimans (Melanosuchus niger) over a period of 17 yr at Mateococha, a black-water lake located in Cuyabeno Wildlife Reserve, western Amazonia, Ecuador. Using standardized spotlight counts and two mark–recapture surveys, we estimated the population abundance, body size structure, and sex ratio in 1994, 2004, and 2011. The maximum number of C. crocodilus recorded in 1994 (147 individuals; 33 individuals/kilometer [ind/km] of lakeshore) declined by 2004 to 94 individuals (21.1 ind/km) and by 2011 to 63 individuals (14.2 ind/km). The number of M. niger recorded was low but constant (5–7 individuals; 1.1–1.6 ind/km) throughout the study, suggesting that factors causing the decline in C. crocodilus were not related to the M. niger population trend. Large C. crocodilus adults (total length 150–220 cm) were frequent in 1994 but became rare in 2004 and 2011. The sex ratio of captured C. crocodilus was male-biased during all periods. The causes of the population decline are unknown, but available evidence suggests that illegal hunting and habitat degradation are likely culprits despite the protected status of the Cuyabeno Reserve. Our findings question the effectiveness of protected areas to ensure long-term survival of caiman populations in Ecuador