Oleas Gallo, Nora Helena
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Oleas Gallo, Nora Helena
Main Affiliation
Quito
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noraoleas@uti.edu.ec
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Scopus Author ID
12645534600

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Alkaloids of Phaedranassa dubia (Kunth) J.F. Macbr. and Phaedranassa brevifolia Meerow (Amaryllidaceae) from Ecuador and its cholinesterase-inhibitory activity

2021 , León K.A. , Inca A. , Tallini L.R. , Osorio E.H. , Robles J. , Bastida J. , Oleas Gallo, Nora Helena

Alzheimer's disease is considered the most common cause of dementia and, in an increasingly aging population worldwide, the quest for treatment is a priority. Amaryllidaceae alkaloids are of main interest because of their cholinesterase inhibition potential, which is the main palliative treatment available for this disease. We evaluated the alkaloidal profile and the in vitro inhibitory activity on acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) of bulb alkaloid extract of Phaedranassa dubia and Phaedranassa brevifolia collected in Ecuador. Using gas chromatography coupled to mass spectrometry (GC-MS), we identified typical Amaryllidaceae alkaloids in these species, highlighting the presence of lycorine-type alkaloids in P. dubia and haemanthamine/crinine-type in P. brevifolia. The species P. dubia and P. brevifolia showed inhibitory activities against AChE (IC50 values of 25.48 ± 0.39 and 3.45 ± 0.29 μg.mL−1, respectively) and BuChE (IC50 values of 114.96 ± 4.94 and 58.89 ± 0.55 μg.mL−1, respectively). Computational experiments allowed us to understand the interactions of the alkaloids identified in these samples toward the active sites of AChE and BuChE. In silico, some alkaloids detected in these Amaryllidaceae species presented higher estimated binding free energy toward BuChE than galanthamine. This is the first study about the alkaloid profile and biological potential of P. brevifolia species. © 2020 SAAB

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Isolation and Characterisation of 11 Microsatellite Loci in the Ecuadorian Hillstar Oreotrochilus chimborazo

2017 , Oleas Gallo, Nora Helena , Harvey N. , Rodríguez-Saltos C.A. , Bonaccorso E.

The Ecuadorian Hillstar Oreotrochilus chimborazo is a high Andean hummingbird that inhabits paramo ecosystems from extreme southern Colombia to southern Ecuador. The species is currently divided into three subspecies that differ in morphology and geographic distribution but no molecular differences have been found between them using mitochondrial markers. The aim of this study was to isolate and test microsatellite loci to further explore possible genetic variability between and within these subspecies. Screening an enriched genomic library of O. chimborazo we obtained eleven polymorphic microsatellite loci. These markers will be used to further elucidate evolutionary patterns in the species.

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Recent diversification in the high Andes: Unveiling the evolutionary history of the Ecuadorian hillstar, Oreotrochilus chimborazo (Apodiformes: Trochilidae)

2021 , Bonaccorso E. , Rodríguez-Saltos C.A. , Freile J.F. , Peñafiel N. , Rosado-Llerena L. , Oleas Gallo, Nora Helena

Studying the genetic signatures of evolutionary diversification in young lineages is among the most promising approaches for unveiling the processes behind speciation. Here, we focus on Oreotrochilus chimborazo, a high Andean species of hummingbird that might have experienced rapid diversification in the recent past. To understand the evolution of this species, we generated a dataset of ten microsatellite markers and complementary data on morphometrics, plumage variation and ecological niches. We applied a series of population and coalescent-based analyses to understand the population structure and differentiation within the species, in addition to the signatures of current and historical gene flow, the location of potential contact zones and the relationships among lineages. We found that O. chimborazo comprises three genetic groups: one corresponding to subspecies O. c. chimborazo, from Chimborazo volcano and surroundings, and two corresponding to the northern and southern ranges of subspecies O. c. jamesonii, found from the extreme south of Colombia to southern Ecuador. We inferred modest levels of both contemporary and historical gene flow and proposed the location of a contact zone between lineages. Also, our coalescent-based analyses supported a rapid split among these three lineages during the mid-to-late Holocene. We discuss our results in the light of past and present potential distributions of the species, in addition to evolutionary trends seen in other Andean hummingbirds. © 2021 The Linnean Society of London, Biological Journal of the Linnean Society.

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Water quality assessment of the cutuchi river basin (Ecuador): A review of technical documents

2021 , Zapata D. , Oleas Gallo, Nora Helena , Páez-Vacas, Mónica , Tobes, Ibon

The Cutuchi River Basin extends over the inter-Andean valley south of the Cotopaxi Volcano, in Ecuador. It flows through two provinces, Cotopaxi and Tungurahua, and its waters are extensively used to irrigate crops that provide food to the main cities in the country. Unfortunately, the basin receives untreated domestic and industrial discharges. The need for an environmental quality assessment of the river has been acknowledged over the years. The aim of this study is to gather information about water quality of the Cutuchi River through a historical bibliographic review. A total of 57 works published between 2007 and 2018 were found, including books, articles, thesis and project reports. Only 18 documents provided biological, physical, or chemical data linked to water quality. The data obtained through the literature review were compared with maximum thresholds from national and international regulations. Unfortunately, revised studies were scattered on time and randomly along the basin and did not provide robust information to evaluate the state of the water-system. Some contamination was detected significantly exceeding safety thresholds. More exhaustive studies along the basin are needed as a baseline to help the decision makers to design management plans and mitigate human impacts. © 2020 Institute of Physics Publishing. All rights reserved.

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Taxonomy based on science is necessary for global conservation

2018 , Thomson S.A. , Pyle R.L. , Ahyong S.T. , Alonso-Zarazaga M. , Ammirati J. , Araya J.F. , Ascher J.S. , Audisio T.L. , Oleas Gallo, Nora Helena

[No abstract available]

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Molecular Markers and Conservation of Plant Species in the Latin-America: The Case of Phaedranassa viridiflora (Amaryllidaceae)

2013 , Oleas Gallo, Nora Helena , Meerow A.W. , Francisco-Ortega J.

Phaedranassa viridiflora (Amaryllidaceae) is an endemic and endangered plant restricted to the Northern Andes in Ecuador. It is known in three locations where it is sympatric with other Phaedranassa species. Phaedranassa viridiflora is the only species of the genus with yellow flowers. We analyzed 13 microsatellite loci to elucidate the genetic structure of the populations of P. viridiflora. Our results provided the first evidence of natural hybridization in the genus (between P. viridiflora and P. dubia in the Pululahua crater of northern Ecuador). The central and southern populations did not show hybridization. Genetic diversity was the highest in the Pululahua population. Central and southern populations have a higher proportion of clones than Pululahua. Bayesian and cluster analysis suggest that the yellow flower type evolved at least three times along the Ecuadorean Andes. In contrast to other Phaedranassa species, Phaedranassa viridiflora shows lower genetic diversity, which is likely related to a vegetative reproductive strategy. © 2013 The New York Botanical Garden (outside the USA).

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In vitro and in silico analysis of galanthine from Zephyranthes carinata as an inhibitor of acetylcholinesterase

2022 , Sierra, K. , de Andrade, J.P. , R. Tallini, L. , Osorio, E.H. , Yañéz, O. , Osorio, M.I. , Oleas Gallo, Nora Helena , García-Beltrán, O. , de S. Borges, W. , Bastida, J. , Osorio, E. , Cortes, N.

Zephyranthes carinata Herb., a specie of the Amaryllidoideae subfamily, has been reported to have inhibitory activity against acetylcholinesterase. However, scientific evidence related to their bioactive alkaloids has been lacking. Thus, this study describes the isolation of the alkaloids of this plant, and their inhibition of the enzymes acetylcholinesterase (eeAChE) and butyrylcholinesterase (eqBuChE), being galanthine the main component. Additionally, haemanthamine, hamayne, lycoramine, lycorine, tazettine, trisphaeridine and vittatine/crinine were also isolated. The results showed that galanthine has significant activity at low micromolar concentrations for eeAChE (IC50 = 1.96 μg/mL). The in-silico study allowed to establish at a molecular level the high affinity and the way galanthine interacts with the active site of the TcAChE enzyme, information that corroborates the result of the experimental IC50. However, according to molecular dynamics (MD) analysis, it is also suggested that galanthine presents a different inhibition mode that the one observed for galanthamine, by presenting interaction with peripheral anionic binding site of the enzyme, which prevents the entrance and exit of molecules from the active site. Thus, in vitro screening assays plus rapid computer development play an essential role in the search for new cholinesterase inhibitors by identifying unknown bio-interactions between bioactive compounds and biological targets. © 2022 The Authors

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Community voices: the importance of diverse networks in academic mentoring

2022 , Deanna, R. , Merkle, B.G. , Chun, K.P. , Navarro-Rosenblatt, D. , Baxter, I. , Oleas Gallo, Nora Helena , Bortolus, A. , Geesink, P. , Diele-Viegas, L. , Aschero, V. , de Leone, M.J. , Oliferuk, S. , Zuo, R. , Cosacov, A. , Grossi, M. , Knapp, S. , Lopez-Mendez, A. , Welchen, E. , Ribone, P. , Auge, G.

[No abstract available]

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Muddy boots beget wisdom: Implications for rare or endangered plant species distribution models

2019 , Oleas Gallo, Nora Helena , Feeley K.J. , Fajardo J. , Meerow A.W. , Gebelein J. , Francisco-Ortega J.

Species distribution models (SDMs) are popular tools for predicting the geographic ranges of species. It is common practice to use georeferenced records obtained from online databases to generate these models. Using three species of Phaedranassa (Amaryllidaceae) from the Northern Andes, we compare the geographic ranges as predicted by SDMs based on online records (after standard data cleaning) with SDMs of these records confirmed through extensive field searches. We also review the identification of herbarium collections. The species' ranges generated with corroborated field records did not agree with the species' ranges based on the online data. Specifically, geographic ranges based on online data were significantly inflated and had significantly different and wider elevational extents compared to the ranges based on verified field records. Our results suggest that to generate accurate predictions of species' ranges, occurrence records need to be carefully evaluated with (1) appropriate filters (e.g., altitude range, ecosystem); (2) taxonomic monographs and/or specialist corroboration; and (3) validation through field searches. This study points out the implications of generating SDMs produced with unverified online records to guide species-specific conservation strategies since inaccurate range predictions can have important consequences when estimating species' extinction risks. © 2019 by the authors.

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Population genetics of the Federally Threatened Miccosukee gooseberry (Ribes echinellum), an endemic North American species

2014 , Oleas Gallo, Nora Helena , von Wettberg E.J.B. , Negrón-Ortiz V.

Ribes echinellum (Coville) Rehder (Miccosukee gooseberry; Grossulariaceae) is a Federally Threatened species known from only two localities: Jefferson County (Florida, FL) and McCormick County (South Carolina, SC). This perennial shrub, ca. 1 m tall, is deciduous, and reproduces both vegetatively (clonal growth) and sexually (seed production). Recent surveys of the FL population revealed a dramatic decline in plant numbers. To assist in conservation and management of this species in FL and SC populations, microsatellite genetic markers were used to identify genotypes and assess the genetic structure of R. echinellum. We genotyped seven microsatellite loci in 102 individuals: 74 collected in FL and 28 in SC. Unbiased heterozygosity was between 0.28 and 0.53. All seven loci were polymorphic, showing a range of 1.52-2.13 effective number of alleles per locus (mean = 1.75). The two populations of R. echinellum show low genetic diversity, especially in SC. Clonality was not widespread, but was higher in the SC population. Both populations show signatures of bottlenecks but isolation by distance was not evident. We found significant deviation from HW equilibrium, with higher number of heterozygotes than expected. However when HW test was done for the combined populations as two separate groups, only FL showed a significant HW test and for SC the test was non-significant. Bayesian analysis and FST values suggest high genetic divergence between the populations. These results are important for developing a recovery plan and an ex situ and reintroduction conservation programs. © 2014 Springer Science+Business Media Dordrecht (outside the USA).

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