Mirian Villavicencio-Vásquez

Mrs. Mirian Villavicencio-Vásquez

Escuela Superior Politecnica del Litoral, Guayaquil, Guayas, Ecuador
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Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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27 July 2022 in Microorganisms
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IMIana Lucia Cruz Mendoza
Iana Lucia Cruz Mendoza
MVMirian Villavicencio-Vásquez
Mirian Villavicencio-Vásquez
PAPaola Aguayo
Paola Aguayo
DMDiana Coello Montoya
Diana Coello Montoya
LPLuis Plaza
Luis Plaza
JCJonathan Ricardo Coronel
Jonathan Ricardo Coronel
Biosurfactants (BS) are amphiphilic molecules that align at the interface reducing the surface tension. BS production is developed as an alternative to synthetic surfactants because they are biodegradable, with low toxicity and high specificity. BS are versatile, and this research proposes using a biosurfactant crude extract (BCE) as part of cleaning products. This paper reported the BCE production from Bacillus subtilis DS03 using a medium with molasses. The BCE product was characterized by different physical and chemical tests under a wide pH range, high temperatures, and emulsifying properties showing successful results. The water surface tension of 72 mN/m was reduced to 34 mN/m with BCE, achieving a critical micelle concentration at 24.66 ppm. BCE was also applied to polystyrene surface as pre-treatment to avoid microbial biofilm development, showing inhibition in more than 90% of Escherichia coli, Staphylococcus aureus, and Listeria monocytogenes above 2000 ppm BCE. The test continued using BCE as post-treatment to remove biofilms, reporting a significant reduction of 50.10% Escherichia coli, 55.77% Staphylococcus aureus, and 59.44% Listeria monocytogenes in a concentration higher than 250 ppm BCE. Finally, a comparison experiment was performed between sodium lauryl ether sulfate (SLES) and BCE (included in commercial formulation), reporting an efficient reduction with the mixtures. The results suggested that BCE is a promising ingredient for cleaning formulations with applications in industrial food applications.

6 May 2022 in Agronomy
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RERODRIGO ESPINOZA
RODRIGO ESPINOZA
DADarlyn José Amaya-Márquez
Darlyn José Amaya-Márquez
C. Miguel PintoC. Miguel Pinto
C. Miguel Pinto
MVMirian Villavicencio-Vásquez
Mirian Villavicencio-Vásquez
DSDaynet Sosa
Daynet Sosa
SPSimón Pérez-Martínez
Simón Pérez-Martínez
One of the main problems in the production of cacao in Ecuador is the disease caused by the fungus Moniliophthora roreri (frosty pod rot) which affects the pods. Here, we evaluate the genetic diversity of this fungus in Ecuador, and its sensitivity to the fungicide azoxystrobin. We evaluated 76 monosporic cultures from the Amazon and the Pacific coast regions. In vitro sensitivity assays tested several doses of the fungicide azoxystrobin to determine the percent of growth inhibition and the IC50. Concentrations of 1 to 0.1 µg mL−1 inhibited the growth of at least 91% of the isolates. Three isolates were the less sensitive (IC50 = 0.0220–0.0364 µg mL−1), two from Guayas (Pacific coast) and one from Sucumbíos (Amazon) provinces. However, M. roreri is highly sensitive, and it could be used in integrated management of the disease. Genetic analyses were carried out by amplifying microsatellite markers (SSR). All the genetic diversity statistics show a higher diversity in the Amazon compared to samples of the coast region; however, the molecular variance was low (FST = 0.11). Discriminant analysis clearly distinguishes three clusters concurrent with the provinces (Sucumbíos, Orellana and El Oro) and a group with the rest of the provinces. Minimum spanning networks shows, unexpectedly, that M. roreri from the coast were derived from at least three independent introductions from the Amazon. Findings are discussed in light of previous Pan-American genetic studies and available historical reports.

25 March 2022 in Acta Agronomica
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DADarlyn José Amaya-Márquez
Darlyn José Amaya-Márquez
FEFernando Espinoza-Lozano
Fernando Espinoza-Lozano
MVMirian Villavicencio-Vásquez
Mirian Villavicencio-Vásquez
DSDaynet Sosa
Daynet Sosa
SPSimón Pérez-Martínez
Simón Pérez-Martínez
Frosty pod rot (FPR) of cacao is caused by Moniliophthora roreri (MR). Effective management must include chemical or biological control, in addition to agronomic tactics. Flutolanil has been effective in controlling FPR. The objective of this research was to determine the response to flutolanil of MR isolates from the Amazon and Coast regions of Ecuador. Percentage of mycelial growth inhibition (PGI), and medium inhibitory concentration (IC50) against three concentrations of the fungicide were determined. One µg mL-1 of flutolanil in the culture medium inhibited completely the growth of the 76 MR isolates. At 0.1 μg mL-1, 74/76 were inhibited between 70-97 % compared to the control. Conversely, at the lower concentrations (0.01-0.001 μg mL-1) the results of inhibition were only of 22 % and 47 %, respectively. Four groups were identified: one included the most sensitive (66/76) to different degrees, and three groups representing 10 isolates that were stimulated at low concentrations of flutolanil. IC50 values were low, indicating very high sensitivity in the MR population. IC50max were 0.1342 and 0.1457 in two isolates from the Coast and the Amazon regions, respectively. Isolates from the Coast were significantly less sensitive to flutolanil than those from the Amazon ( IC50 = 0.046 ± 0.03 and IC50 = 0.030 ± 0.02, respectively), however, the differences were minimal. There were no significant differences when comparing the provinces. The most stimulated isolates were found in the provinces of Orellana and Los Ríos. It is concluded that flutolanil seems effective against the causal agent of FPR in Ecuador, both Coast and Amazon regions.

18 February 2025 in Scientia Agropecuaria
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FEFernando Espinoza-Lozano
Fernando Espinoza-Lozano
MVMirian Villavicencio-Vásquez
Mirian Villavicencio-Vásquez
LSLizette Serrano
Lizette Serrano
DSDaynet Sosa
Daynet Sosa
JCJonathan Ricardo Coronel
Jonathan Ricardo Coronel
MVMarcos Vera-Morales
Marcos Vera-Morales
Cacao cultivation is one of the main agricultural products of Ecuador, known internationally for its quality and aroma. However, it is affected by fungal diseases including Moniliophthora roreri, Moniliophthora perniciosa, Phytophthora spp., and Colletotrichum spp. The genus Colletotrichum spp. is known for its characteristics that complicate traditional taxonomic identification. In cacao cultivation, it is one of the most frequently found species as an endophyte of leaves and fruits, yet it is also reported to cause the disease known as anthracnose on leaves and fruits. The objective of this work was to identify at the species level 16 Colletotrichum isolates, 13 from healthy leaf endophytes and 3 from pods with symptoms, through multilocus analysis of the ITS1, 5.8S, and ITS2 region, and partial sequences of the TUB2 and GAPDH genes. Subsequently, their pathogenicity was evaluated by inoculating healthy cacao pods and measuring the damage caused. The 16 isolates were identified as follows: from the gloeosporioides complex, C. siamense 6, C. chrysophilum 6, C. theobromicola 2 and from the boninense complex, C. karstii 2. The most frequently found species were those that caused symptoms, especially C. siamense, to which the strains were isolated from symptomatic pods belonged. This work provides relevant and accurate information about the diversity of Colletotrichum species that colonize cocoa plantations and identifies which species might cause the disease known as anthracnose. Additionally, it allows for a more precise diagnosis and consequently better treatment.

16 February 2026 in Scientia Agropecuaria
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Lorena Monserrate-MaggiLorena Monserrate-Maggi
Lorena Monserrate-Maggi
AQAdela Quevedo
Adela Quevedo
LSLizette Serrano
Lizette Serrano
MVMarcos Vera-Morales
Marcos Vera-Morales
MVMirian Villavicencio-Vásquez
Mirian Villavicencio-Vásquez
FMFreddy Magdama
Freddy Magdama
Bananas (Musa spp.), often reported together with plantains, are among the most traded fruit commodities worldwide, particularly in terms of export volume and value, with Ecuador recognized as the leading global exporter, supplying approximately one quarter of the total international trade. However, its production is increasingly threatened by climate change and fungal diseases such as Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense Tropical Race 4 (Foc TR4). To support preventive management strategies against Foc TR4, this study evaluated the in vitro efficacy of nine commercial disinfectants available in Ecuador—including quaternary ammonium compounds (QACs), oxidizing agents, aldehydes, and alkaline substances—against conidia and chlamydospores of several Foc race 1 strains (VCG0120) as a model organism. Different concentrations and contact times were tested in the presence and absence of organic matter. Chlamydospores exhibited higher resistance than conidia, requiring greater concentrations for inhibition. Aldehyde formulations and QACs achieved the lowest minimum inhibitory concentrations (<1,000 ppm) and remained effective under organic load and variable contact times. These findings emphasize the need to select disinfectants with consistent efficacy under field-relevant conditions to ensure the application of proper biosecurity measures.

15 March 2025 in Revista Peruana de Biología
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DADarlyn José Amaya-Márquez
Darlyn José Amaya-Márquez
MVMirian Villavicencio-Vásquez
Mirian Villavicencio-Vásquez
DPDanny Daniel Avilés Párraga
Danny Daniel Avilés Párraga
Yoansy GarcíaYoansy García
Yoansy García
RERodrigo Fernando Espinoza-Lozano
Rodrigo Fernando Espinoza-Lozano
En este estudio se analizaron dos cepas de Phytophthora (PP8 y PPAGR) aisladas de mazorcas de cacao (Theobroma cacao) con síntomas característicos de la enfermedad de la mazorca negra, recolectadas en la provincia de Los Ríos, Ecuador. Mediante análisis molecular, utilizando los cebadores de la región ITS1, 5.8S e ITS2 (ITS4 - ITS6) y la secuenciación del producto amplificado, se determinó que ambas cepas pertenecen a la especie P. palmivora. Adicionalmente, se evaluó la virulencia de las cepas mediante su inoculación en brotes de cacao Nacional Fino de Aroma y CCN-51, empleando un diseño completamente al azar factorial con siete repeticiones, donde cada brote de cacao se consideró como unidad experimental. Los resultados indicaron que la cepa PP8 presentó una incidencia y severidad del 100 % en brotes de cacao Nacional Fino de Aroma, evidenciando una alta susceptibilidad a Phytophthora. Asimismo, se determinó que la cepa PP8 infecta exclusivamente los brotes de cacao Nacional, mientras que los brotes de CCN-51 no fueron afectados por ninguna de las cepas evaluadas. En conclusión, el impacto de Phytophthora varía en función de la virulencia del aislado y de la variedad de cacao.