Artículos científicos

URI permanente para esta colecciónhttp://10.0.96.45:4000/handle/11056/14821

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Conservation genetics of the tropical gar (Atractosteus tropicus, Lepisosteidae)
(Springer (Alemania), 2023) Palacios Mejia, Maura; Arias‑Rodriguez, Lenin; Arciniega, Martha; Rodríguez, Victoria; Barraza Sandoval, José Enrique; Herrera, Néstor; Marroquín Mora, Dora Carolina; Ulloa Rojas, Juan B.; Márquez Couturier, Gabriel; Voelker, Gary; Tobler, Michael
Abstract. The tropical gar (Atractosteus tropicus) is the smallest member of the family Lepisosteidae; yet this species has a large socioeconomic impact in México and Central America where it is traditionally harvested commercially and for subsistence. While natural populations of tropical gar have been dwindling throughout its natural range, it is also an emergent aquaculture species that is produced in local hatcheries and grown out in privately owned ponds. The increased pressure on natural populations of A. tropicus and its increasing use in aquaculture production poses potential conflicts for the management and conservation of natural populations. Here, we investigated the population genetic structure of tropical gar populations, including over 200 individuals sampled in México, El Salvador, and Costa Rica. Using 11 microsatellite loci, we identified three genetic clusters with distinct geographic distributions, including a cluster in drainages along the Pacific versant of Central America, a cluster in the Grijalva and Usumacinta River basins that drain into the Gulf of México, and a cluster in the Río San Juan that drains into the Caribbean Sea. Given the degree of divergence observed, these results indicate the potential presence of evolutionary significant units within tropical gar that warrant separate fisheries and conservation management. We also found that tropical gar from an aquaculture facility along the Pacific versant of México were derived from Atlantic versant populations, indicating that individuals have already been translocated across biogeographic boundaries. We discuss how such translocations can negatively impact the natural population structure of tropical gar and provide recommendations for future research and aquaculture practices.
Drought tolerance memory transmission by citrus buds
(Elsevier (Países Bajos), 2022) Rodrigues de Oliveira Sousa, Andressa; Ferreira Ribas, Rogério; Coelho Filho, Mauricio Antônio; Freschi, Luciano; Fortes Ferreira, Claudia; dos Santos Soares Filho, Walter; Pérez-Molina, Junior Pastor; da Silva Gesteira, Abelmon
Abstract. Plants face recurrent drought events, and previous stresses can influence their responses to subsequent stress episodes. Studies on drought stress memory are recent in citriculture, although they show promise as a tool for crop improvement. Here, we investigated whether stress memory mechanisms can be detected in citrus plants grafted with buds from plants subjected to recurrent water deficit. Three rootstock varieties, namely ‘Rangpur Santa Cruz’ lime, ‘Sunki Maravilha’ mandarin and ‘Sunki Tropical’ mandarin, in combination with ‘Valencia’ orange, were either maintained under full irrigation or subjected to one, two, or three water deficit cycles. Buds from ‘Valencia’ orange were grafted onto ‘Swingle’ citrumelo rootstocks and were evaluated. This combination displayed improved physiological and biochemical performance under water limitation, especially ‘Valencia’ buds grafted onto ‘Sunki Maravilha’, with better photosynthetic performance under water deficit. These findings indicate that genotype-dependent epigenetic memory is a key factor in restoring citrus plants’ capacity to rely on previous stress experiences to restore better photosynthetic and physiological responses when undergoing new water deficit events. Therefore, epigenetic marks can be stored and transmitted to new citrus plants and are a promising alternative to enable increased water deficit tolerance when plants are then challenged by drought-prone environments.
Root deformation affects the allometric relationships of young plants of Genipa americana under contrasting light conditions
(Springer (Alemania), 2023) SOUSA SANTOS, CATRIANE; Freitas Cerqueira, Amanda; Dalmolin, Ândrea Carla; Alves de Almeida, Álvaro; Santana dos Santos, Martielly; Barreto dos Santos, Roberta; Pérez‑Molina, Junior Pastor; Schramm Mielke, Marcelo
Abstract. We conducted a study aiming to evaluate the effects of light intensity and root deformation on the prediction capacity of Genipa americana seedling biomass, using allometric models. Seedlings with and without root deformation were placed under high and low light intensity (21.6 and 0.66 mol m−2 day−1, respectively). Stem diameter (D), height (H), and leaves, stems, root, and total dry mass were measured. Analysis of covariance was used to test whether the relationship between seedling biomass and D2 or D2H varied for each treatment combination. Low light influenced the allometric relationship between biomass and D2 in stems. Root deformation with low light influenced the relationship between biomass and D2 in the root. Light and root deformation influenced the relationship between biomass and D2H in all seedling vegetative structures. As a result, “full” allometric models, which varied with treatment combinations, were equally accurate and precise at predicting biomass than “reduced” models, which did not vary with treatment for leaves and total dry mass using D2. However, “full” and “reduced” allometric models using D2H had the opposite effect as “full” models were more accurate and precise at predicting leaves and total biomass than “reduced” models. Our results showed that some allometric relationships of young G. americana plants were directly affected by root deformation and low light intensity, while some were conservative i.e. unaffected by light and root deformation treatments. The best allometric equations were obtained with models that used stem diameter as the predictor variable.
Allometric models to estimate the individual leaf area of arabica coffee: an approach from frequentist and Bayesian statistics
(Springer (Alemania), 2023) Schramm Mielke, Marcelo; Oliveira Santos, Gabriel; Silva Lopes, Emile Caroline; Schilling, Ana Cristina; Santana dos Santos, Martielly; Pérez‑Molina, Junior Pastor
Abstract. Over the years, advances in technological and computational procedures have been made available for studies on plant morphology and physiology, and the cross-checking between the oldest and most recent information available in the literature is an important way to consolidate scientific knowledge. Due to its economic importance, studies on leaf allometry of Coffea arabica genotypes have been published in the last 50 years, making it an excellent model plant for comparing the technological advances in data collection and analysis for the development of individual leaf area prediction models. We conducted a study aiming the comparison of four allometric models available in the literature with a new allometric model from a simple linear regression with Bayesian statistics adjustment based on Markov chain Monte Carlo (MCMC) to estimate the individual leaf area (LA) of two C. arabica genotypes. All leaves of six plants belonging to two cultivars (‘Catuaí Vermelho’ IAC44 and ‘Catucaí Vermelho’ 19/08) with approximately 1 year old were collected (n = 563). Measurements of length of leaf blade, width and LA were obtained from scanned images, using the software ImageJ. For regressions between observed and predicted LA, all the models available in the literature presented high coefficients of determination (R2), very low root-mean-square errors (RMSE) and very similar values for the Akaike Information Criterion (AIC). As expected, for regressions between observed and predicted LA our Bayesian regression model presented lower values of RMSE and AIC than the previous models proposed in the literature. Despite technological advances and the development of new computational procedures, all models tested in this study provided highly accurate predictions of the LA for C. arabica genotypes.
Photochemical efficiency and lethal leaf dehydration in seedlings of nine tropical tree species
(Springer (Alemania), 2024) Schramm Mielke, Marcelo; Almeida Oliveira, Leticia; Santana dos Santos, Martielly; Pérez‑Molina, Junior Pastor; Freitas Cerqueira, Amanda; Dalmolin, Ândrea Carla; Sousa‑Santos, Catriane; Reis de Brito, Carolina
Abstract. The knowledge about vulnerability of tree seedlings to severe droughts is important in order to select the most suitable species for forestry plantations in a context of extreme weather events induced by global climate change. We conducted a study aiming to evaluate the effects of lethal leaf dehydration on seedlings of nine tropical tree species cohabiting the same forest ecosystem, but differing in terms shade tolerance, maximum height, geographical distribution, and leaf mass per area. For this, the percentual loss of photochemical efficiency, measured as the loss of maximum quantum efficiency of photosystem II during leaf dehydration (PL[Fv/Fm]) was investigated. Statistically significant differences were found between species for the average values of the relative water content (RWC) in which there is a loss of 10% and 50% of Fv/Fm. The species were separated in three groups: (a) species that showed the highest Fv/Fm losses at high RWC values, (b) intermediate species, and (c) species that showed significant Fv/Fm loss only at very low values of RWC. The PL[Fv/Fm] during leaf dehydration can be an useful methodology to select tree species for plantations in sites prone to severe droughts associated to extreme weather events.
Evaluación del desarrollo de estructuras infectivas y efecto de Beauveria bassiana en el crecimiento de plántulas de tomate (Solanum lycopersicum) bajo condiciones de alta temperatura
(Universidad Nacional (Costa Rica), 2025) Villalobos-Álvarez, Estefani Mariel; Castro-Vásquez, Ruth; Vega-Corrales, Luis; Pérez-Molina, Junior Pastor
Resumen. [Objetivo] Se evaluó el desarrollo in vitro de estructuras infectivas de cepas de Beauveria spp. y su efecto en el crecimiento de plántulas de tomate (Solanum lycopersicum) en condiciones de alta temperatura. [Metodología] Se comparó el desarrollo de 5 cepas de Beauveria spp. en condiciones óptimas y de alta temperatura (hasta 35 °C) en relación con la producción de conidios, crecimiento del micelio y germinación. Posteriormente, se evaluó el efecto de la cepa con mejores resultados de desarrollo en el crecimiento de plántulas de S. lycopersicum, cultivar ‘Gladiator’, bajo las mismas condiciones de temperatura. Cada cepa fue identificada por PCR con la amplificación de la zona intergénica nuclear Bloc y el factor de elongación EF1-𝛼. [Resultados] Las cepas se identificaron como Beauveria bassiana de linaje neotropical. No se encontraron diferencias significativas en la producción de conidios entre tratamientos (p-value >0.05) a diferencia del crecimiento del micelio. Se observaron cambios leves, pero significativos en las relaciones de raíz a superficie, no así en las demás variables evaluadas y solo para las plántulas a las que se les aplicó la cepa H-31 [Conclusiones] Se determinó el potencial entomopatógeno de B. bassiana en condiciones de estrés ambiental como las altas temperaturas del clima tropical. Se establece, además, la base para la bioprospección de microorganismos termotolerantes con potencial agrobiotecnológico en escenarios de calentamiento global.
Screening Genipa americana Progenies for Their Ability to Maintain Leaf Vitality Under Severe Dehydration Using Chlorophyll Fluorescence
(Multidisciplinary Digital Publishing Institute (MDPI) (Suiza), 2025) Sousa-Santos, Catriane; Pérez-Molina, Junior Pastor; Freitas Cerqueira, Amanda; Dalmolin, Ândrea Carla; Alves de Almeida, Álvaro; Santana dos Santos, Martielly; Schramm Mielke, Marcelo
Abstract. Damage to the photosynthetic apparatus during leaf dehydration is an indicator of the maintenance of leaf vitality and the resilience of tree seedlings to severe drought. Genipa americana is a tree widely distributed in the neotropical region but with great ecological and sociocultural importance in the south of the state of Bahia, Brazil, where its fruits are harvested from subspontaneous trees. This study aimed to compare the feasibility of the maximum quantum efficiency of photosystem II (Fv/Fm) and performance indexes derived from the JIP test, i.e., performance index on absorption basis (PIabs) and total performance index (PItotal), for screening G. americana seedlings from different mother plants for leaf damage caused by dehydration. From leaf dehydration curves, we calculated the values of relative water content (RWC) in which Fv/Fm, PIabs, and PItotal reach a loss of 10% and 50% in relation to the values of fully hydrated leaves. PItotal was the only parameter that revealed consistent significant differences between progenies for RWC at 50% of percentage loss. Significant differences were observed among progenies for leaf traits; however, no correlation was detected between these traits and chlorophyll fluorescence parameters. Monitoring the PItotal values during leaf dehydration is a useful tool for screening G. americana progenies in relation to their capacity to maintain leaf vitality under occasional severe droughts.
The Leaf Thermotolerance of Nine Tree Species with Varying Geographic Range Sizes in a Climate Change-Threatened Hotspot
(Multidisciplinary Digital Publishing Institute (MDPI) (Suiza), 2025) de Brito, Carolina Reis; Pérez-Molina, Junior Pastor; Santana dos Santos, Martielly; Rocha-Santos, Larissa; Schramm Mielke, Marcelo
Abstract. The Brazilian Atlantic Forest (AF) is recognized as one of the most threatened biodiversity hotspots by global climate change. Here, we examined the leaf traits (leaf mass area, leaf thickness, and chlorophyll content) and leaf thermotolerance (T50 and TCrit) of seedlings of nine species of AF trees grown experimentally in order to foresee how extreme heat events will affect the forest’s regeneration and diversity. Based on geographic range size, the species were classified into three groups, namely, species with a restricted-range distribution (endemic to the AF), species with an intermediate-range distribution (throughout the Brazilian tropical territory), and species with a wide-range distribution (Latin America). We found that the restricted-range group did not present lower thermotolerance compared to intermediate- and wide-range species groups. Surprisingly, leaf mass area had no effect on thermotolerance indices, while chlorophyll content and leaf thickness positively influenced T50 and TCrit. Some species-specific responses to high-temperature stress deserve attention for tropical tree conservation, as is the case of Arapatiella psylophylla, a vulnerable endemic species with a very restricted-range distribution. Our results suggest that the species-specific leaf thermotolerance is an important criterion to be considered for tropical tree forest conservation in the context of global climate change.
Antimicrobial Activity of Diverse Chemotypes of Lippia graveolens Against Aeromonas hydrophila Isolated from Oreochromis niloticus
(Universidad Nacional (Costa Rica), 2024) García-Pérez, Josué; Pérez-Sabino, Juan; Mendoza-Elvira, Susana; Ribeiro da Silva, Antonio Jorge; Ulloa-Rojas, Juan
Abstract. [Objective] This study aimed to evaluate the antimicrobial efficacy of essential oil (EO) from diverse chemotypes of Lippia graveolens against oxytetracycline-resistant Aeromonas hydrophila, which primarily affects the tilapia aquaculture (O. niloticus) in Guatemala. [Methodology] L. graveolens were collected in three departments in Guatemala. The EO was obtained by hydrodistillation and characterized using gas chromatography and mass spectrometry (GC/MS). Subsequently, an antimicrobial assay was conducted using disk and dilution susceptibility tests and evaluation of synergistic interactions among the chemotypes. Each test was performed in triplicate. [Results] The analysis revealed the presence of twenty-seven compounds in the EO obtained from the chemotypes, with the main class being monoterpenes. The major constituents identified were cis-Dihydro-β-terpineol (8.84%) in chemotype I, carvacrol (51.82%) in chemotype II, and thymol (79.62%) in chemotype III. All EO chemotypes of L. graveolens demonstrated the ability to inhibit the A. hydrophila growth. Thymol chemotype exhibited the strongest inhibitory effect against bacterial growth, with a minimum inhibitory concentration (MIC) of 92.4 μg/mL and a minimum bactericidal concentration (MBC) of 184.8 μg/mL. Furthermore, the results suggest that there is no synergistic or additive effect when combining different chemotypes of L. graveolens. [Conclusions] This is the first report of L. graveolens chemotypes exhibiting antimicrobial activity against oxytetracycline-resistant A. hydrophila. The findings suggest that the chemotype thymol could be a potential treatment for infections in the tilapia aquaculture in Guatemala.
Seasonal and Spatial Dynamics of the Intestinal Microbiome in Tropical Freshwater Fish: Insights from Astyanaxaeneus and Brycon costaricensis in the Peñas Blancas River Basin, Costa Rica
(BioMed Central Ltd, 2025-10-02) Cortez-Martínez, Manuel; Medrano-Lozano, Josmari; Blanco-Peña, Kinndle; Quesada-Alvarado, Francisco; Solano-Campos, Frank
Abtract. The intestinal microbiome plays a crucial role in fish development and health, facilitating essential functions such as nutrient uptake, immune system response, and disease resistance. However, the microbial communities of Neotropical freshwater fish, such as Astyanax aeneus and Brycon costaricensis, remain largely unexplored. Understanding how microbiomes vary in relation to environmental gradients is key to identifying potential sentinel species for ecosystem monitoring. To understand the dynamics of bacterial diversity and community structure, we collected intestinal content samples from 165 individuals of both species from six points along the Peñas Blancas river basin, Costa Rica, during the dry and rainy seasons and during an intermediate period. Results Metabarcoding analysis of the 16 S rRNA gene revealed that the intestinal microbial communities of both species were dominated primarily by the genera Cetobacterium, Clostridium, Romboutsia and Plesiomonas. No significant differences were detected in the relative abundance of taxa, metabolic pathways or community structure between the two species and only at the Dam site, a significant increase in the Shannon index was detected in B. costaricensis. Conversely, distinct differences in microbial network properties were found, with A. aeneus showing a lower clustering coefficient and modularity, a shorter average path length and a greater number of hubs. Site and season influenced the microbial community structure of A. aeneus but not the relative abundance of taxa. Similarly, differentially abundant metabolic pathways, including xenobiotic degradation, were enriched in A. aeneus. Conclusions The similarities in microbiome diversity and structure in both species could arise from parallels in taxonomy, habitat and diet. However, temporal and spatial shifts in the A. aeneus microbial community structure may be associated with sensitivity to changes in environmental stressors such as precipitation, temperature, and runoff. Microbial network analysis revealed that taxa in A. aeneus are more tightly interconnected and form fewer distinct clusters, making it a promising bioindicator for monitoring water quality and anthropogenic impacts.
Estrategias de mediación que facilitan la integración del contexto en el aprendizaje de Biología con estudiantes de ciclo diversificado, Costa Rica- 2023
(Universidad Estatal a Distancia (Costa Rica), 2024) Coto-Chinchilla, Valeria; Barrantes-León, Jesús Irán; Guevara-Mora, Meyer; Pereira-Chaves, José Miguel
Resumen. El presente estudio tuvo como finalidad identificar las principales estrategias de mediación que las personas docentes aplican en las clases de Biología para la integración del contexto, si consideró el entorno educativo, la comunidad o las propias vivencias estudiantiles en el proceso enseñanza y aprendizaje, los informantes fueron las personas estudiantes que participan en el proyecto OLICOCIBI (Olimpiadas Costarricense de Ciencias Biológicas) de la Universidad Nacional de Costa Rica. Para ello, se realizaron entrevistas a estudiantes finalistas de las Olimpiadas, donde se les consultó si el docente utilizaban recursos para enseñarles sobre los distintos contenidos por medio del uso del contexto; además, se realizó un grupo focal compuesto por los docentes de los estudiantes que clasificaron a la final de la OLICICOBI, en la cual se analizaron cuáles estrategias de mediación utilizan y los beneficios que conlleva utilizar un aprendizaje contextualizado, dentro delos principales resultados, se evidenció que para la integración del contexto las personas docentes implementan estrategias como el aprendizaje basado en proyectos, aula invertida, aprendizaje cooperativo y estrategia magistral para la potenciación de habilidades cognitivas, sociales, afectivas y para la vida del estudiantado. Se concluyó que, a partir de la mediación pedagógica, se promueve la motivación y el interés en el estudiante para seguir aprendiendo y ser consciente de lo que le rodea y la realidad en la que se encuentra vista desde los contenidos desarrollados en la asignatura de Biología.
Acciones de mitigación y adaptación ante la erosión costera de playas arenosas del Caribe Sur, Costa Rica
(Instituto de Geografía (México), 2024) Castillo Chinchilla, Maikol; Piedra Castro, Lilliana María; Pereira Chaves, José Miguel; Sierra Sierra, Luis
Resumen. Las zonas costeras del mundo enfrentan serios problemas debido a las consecuencias de la erosión en playas. Si bien es cierto que se realizan esfuerzos por contener este avance del mar, estas en ocasiones se convierten en acciones aisladas debido a la carencia de instrumentos que orienten el proceso de toma de decisiones. Esta falta de metodologías y proyectos dirigidos a la contención del avance del mar también afecta al Caribe Sur de Costa Rica. El objetivo de la investigación fue formular un plan de acción que integre soluciones basadas en la naturaleza que puedan ser implementadas como herramientas de mitigación ante la erosión costera de las playas arenosas del Caribe Sur, Costa Rica. Para esto se trabajó con un grupo focal donde los actores sociales manifestaron sus percepciones respecto a los principales problemas que ocasiona la erosión de la costa, y realizaron reconocimientos de las playas arenosas de comunidades como Vizcaya, Estrella, Cahuita, Manzanillo y Gandoca. La información que brindaron se clasificó con el fin de valorar la viabilidad para ser incorporada en el plan de acción. Además, se realizó una selecta revisión bibliográfica respecto a experiencias en otros países que han implementado planes de acción y soluciones basadas en la naturaleza. Los resultados obtenidos a partir de los grupos focales muestran que el 95% de los actores locales reconoce la existencia de al menos tres impactos que son los detonantes del deterioro de la costa, a saber: arrastre de arena de las playas, pérdida de vegetación de la duna y de biodiversidad asociada. Los participantes también reconocieron el efecto que tiene el avance del mar hacia el continente sobre la fauna (57%) y la vegetación (36%) como agentes que producen mayor afectación. Reconocen la existencia de al menos cuatro ejes principales que tienen relación con este tema, como lo son la disminución del ingreso económico y la reducción de la entrada de turistas a las playas, principalmente de aquellas zonas que han sido identificadas previamente con tendencia erosiva fuerte, entre ellas Puerto Vargas, Puerto Viejo, Manzanillo y Gandoca. Con base en la información recopilada se logró definir un plan de acción que consta de seis objetivos con sus respectivos indicadores, resultados esperados y actores involucrados en la ejecución. En esta herramienta, además, se detallan soluciones basadas en la naturaleza que pueden ser incorporadas para poner en marcha, tomando en cuenta las características que tiene cada una de las playas arenosas consideradas para esta investigación. De ahí que las medidas propuestas incluyen obras de tipo rígido y blandas, mismas que contribuyen a la protección de los ecosistemas, al permitir la reducción de la energía del oleaje, la diversificación de los hábitats marinos, las actividades de aprovechamiento de recursos disponibles para la pesca de subsistencia y el incremento de la resiliencia de las playas arenosas. Se concluye que para el Caribe Sur de Costa Rica existe terreno fértil para la realización y ejecución de pequeños proyectos con enfoque en costas vivas y soluciones basadas en la naturaleza. Es importante destacar que las acciones de mitigación propuestas deben estar contenidas en este plan de forma tal que sea integral, solidario y sostenible en el tiempo, lo cual permitirá que exista de manera efectiva la adaptación de las comunidades costeras ante la problemática que ocasiona la erosión de la costa.
Caracterización del Bosque y el Gradiente Ambiental en dos áreas protegidas con Erosión Costera en el Caribe Sur de Costa Rica
(Universidad Nacional de Colombia (Colombia), 2024) Castillo-Chinchilla, Maikol; Piedra Castro, Lilliana María; Pereira Chaves, José; Sierra-Sierra, Luis; Carvajal-Sánchez, José
Resumen. La erosión costera está relacionada directamente con el desbalance sedimentario que afecta las playas a nivel mundial, y tiene el potencial de cambiar las condiciones que requieren las comunidades vegetales. El objetivo de esta investigación es caracterizar la composición del bosque y el gradiente ambiental en dos áreas protegidas con erosión costera en el Caribe Sur de Costa Rica. Se realizaron 70 parcelas circulares de 15 m de diámetro que abarcaron desde los 50 m y hasta los 200 m tierra adentro, ubicados de manera perpendicular a las playas del Parque Nacional Cahuita (PNC) y Refugio Nacional de Vida Silvestre Gandoca-Manzanillo (REGAMA), que han sido identificadas previamente con tendencia erosiva fuerte entre 1960-2023. En cada parcela, se midieron parámetros fisicoquímicos y ambientales, se identificaron las especies de árboles y se analizaron las texturas del suelo. Se evidenció una zonificación que abarca desde los 50 m y hasta los 200 m respecto al mar, principalmente para los análisis fisicoquímicos y la textura del suelo, que inciden en la composición y estructura del bosque. Tanto en el PNC como en el REGAMA se destaca un ensamble básico de especies que funcionan como estabilizadoras de las reservas de sedimento de playas arenosas, que incluyen a Prioria copaifera, Lonchocarpus heptaphyllus, Pterocarpus officinalis, Rhizophora mangle, Laguncularia racemosa y Tabernamontana alba. Se concluye que, en ambas áreas protegidas, la erosión costera tiene efectos sobre la composición del bosque e incide en los gradientes ambientales que se presentan en los primeros metros de la costa.
Análisis de las estrategias de enseñanza utilizadas por docentes de educación secundaria costarricense en el tema configuración electrónica
(Universidad Estatal a Distancia (UNED) (Costa Rica), 2025) Piedra Marín, Gilberto; Pereira Chaves, José; Cervantes Altamirano, Adrián; López Rodríguez, Merilin
Resumen. En esta investigación se analizaron las estrategias didácticas utilizadas por las personas docentes de Química de educación secundaria en Costa Rica, al abordar el tema configuración electrónica. El estudio se desarrolló bajo un enfoque mixto con predominancia cualitativa utilizando un diseño de tipo incrustado concurrente (CUAL-cuan). La información se recolectó durante los meses de septiembre y octubre de 2021 utilizando un cuestionario dirigido a las personas docentes, una encuesta dirigida a las personas estudiantes y la técnica de grupo focal. La población estudiada incluyó a 10 personas docentes y 150 personas estudiantes de cuatro instituciones educativas públicas de Costa Rica (Liceo Fernando Volio, Liceo Laboratorio de Liberia, Liceo UNESCO y Liceo Diurno de Río Frío). Se encontró que, durante la mediación pedagógica, las personas estudiantes experimentaron estados de ánimo positivos (motivación, emoción, diversión) y negativos (tensión, confusión) que incidieron en el proceso enseñanza-aprendizaje y que un alto porcentaje de las personas estudiantes afirmó comprender el tema configuración electrónica, así como percibir el propósito de las estrategias utilizadas. Se concluyó que el dominio conceptual de las personas docentes para abordar el tema configuración electrónica fue el adecuado y que las estrategias didácticas más empleadas por las personas docentes carecían de componentes dinámicos. Adicionalmente, se concluyó que las estrategias didácticas dinámicas (uso de simuladores, aplicaciones y plataformas web, entre otros) se consideran apropiadas para mejorar el proceso de enseñanza-aprendizaje, pero su implementación se ve limitada por la falta de capacitación y las restricciones de tiempo de las personas docentes.
Factors influencing fumonisin B1 contamination in maize: insights from two production regions in Costa Rica
(Springer Nature (Alemania), 2024) Sánchez‑Zúñiga, Katherine; Rivera‑Méndez, William; Campos‑Boza, Stefany; Araya‑Valverde, Emanuel; Solano-Campos, Frank; Vinas, Maria
Abstract. Maize (Zea mays L.) is an important cereal crop worldwide. Contaminated maize kernels pose a significant mycotoxin exposure risk for humans in Latin America. Fumonisins, the most prevalent mycotoxin in maize, typically occur during pre-harvest conditions leading to significant economic losses. Various factors, including weather conditions, may influence this contamination. This study aimed to determine the association between fumonisin B1 (FB1) contamination, prevalence of Fusarium verticillioides, weather conditions and kernel quality in the two primary maize production areas in Costa Rica (Brunca and Chorotega). All maize samples (100%) showed FB1 contamination, with higher concentrations in samples from Brunca region, consistent with the presence of F. verticilliodes. Weather conditions appeared to play an important role in this contamination, since Brunca region had the highest mean temperature and relative humidity after maize silking (R1) and the total monthly rainfall in this region was significantly higher during the last two months of maize cultivation (grain-filling and physiological maturity stages R3 to R6). Interestingly, this study found a negative correlation between grain damage and kernel contamination with FB1 and F. verticillioides. The concentration of mineral nutrients in kernels from both regions was largely similar. Most nutrients in kernels exhibited a negative correlation with FB1, particularly nitrogen. Zinc and phosphorus were the only nutrients in kernels showing a positive correlation with FB1 in samples from the Brunca region. The results highlight elevated levels of FB1 contamination in maize and contribute to a better understanding of pre-harvest factors influencing FB1 contamination in tropical conditions.
Microbial diversity and community structure of microalgae (Nannochloropsis oculata) and rotifer (Brachionus plicatilis) in aquaculture by 16S rRNA amplicon‑based sequencing
(Springer Nature (Alemania), 2025) Carranza‑Quirós, Andrés; Solano-Campos, Frank; Carvajal Oses, Milagro; Chacón‑Guzmán, Jonathan; Navarrete, Paola; Reinoso, Samira; Umaña‑Castro, Rodolfo
Abstract. Live cultures, including Nannochloropsis oculata and Brachionus plicatilis, are essential in aquaculture due to its economic and nutritional value for commercial fish species. Pathogens and probiotics can be introduced to aquaculture systems by live feed, with variations in abundance influenced by environmental physicochemical parameters. To investigate this, amplicon sequencing of the V3-V4 region of the 16S rRNA was conducted using Illumina MiSeq to elucidate bacterial abundances and their variations in response to changes in physicochemical parameters in live feed cultures. Results revealed that pathogens like, Tenacibaculum, predominantly found in rotifer cultures, was inhibited under dissolved oxygen levels of 6.87–8.19 mg/L and pH levels of 8.63–9.23. Winogradskyella, mainly present on day 1 of the microalgae culture, thrived under these same conditions. Potential probiotics were also analyzed. Phaeodactylibacter, primarily found on day 1 of microalgae cultures, was favored by dissolved oxygen levels of 7.11–7.68 mg/L and pH levels of 8.63–9.23 but was inhibited by nitrite levels of 0.46–0.5 mg/L. Overall, dissolved oxygen was the key parameter modulating microbial diversity. This study shows that optimizing environmental parameters can enhance culture health by promoting probiotics and reducing harmful bacteria.
Thermal energetics of bats of the family Vespertilionidae: An evolutionary approach
(Elsevier (Países Bajos), 2025) Araya Berdon, Jorge; Medina-Bello, Kevin I.; Carballo-Morales, Jorge D.; Saldaña-Vázquez, Romeo A.; Villalobos, Federico
Abstract. Thermal energetics define the way animals spend energy for thermoregulation. In this regard, numerous studies have determined that body mass (Mb) is the most influential morphological trait affecting the thermal traits in different species of birds and mammals. However, most of the studies have been focused on the basal metabolic rate (BMR), while other thermal traits have been less studied. We addressed this gap by examining thermal variables on bats of the family Vespertilionidae. Using open-flow respirometry, we measured BMR, absolute thermal conductance (C’), lower and upper critical temperatures (TLC and TUC), and breadth of the thermoneutral zone (TNZb) of 16 bat species ranging in Mb from ~ 4.0–21.0 g from central Mexico. We: 1) combined our empirical data with information gathered from the literature and conducted phylogenetic analyses to investigate the relationship between Mb and thermal traits, 2) tested the relationship between mass independent C’ and mass independent BMR with TLC and TUC of bats, and the relationship between critical temperatures and TNZb, and 3) mapped the thermal energetic traits along the phylogeny to explore their evolutionary trends. We found a positive relationship between Mb and BMR and absolute C’ but not to TLC, TUC and TNZb of bats. Mass independent BMR and mass independent C’ were positively related to TLC and TUC. Finally, TLC showed a negative relationship with TNZb while TUC exhibited a positive relationship with this thermal trait. The phylogenetic approach indicates that over the evolutionary history, BMR and C´have decreased while TLC, TUC and TNZb have increased. Our results suggest that: 1) differences in the limits of the TNZ and C’ may have helped bats to avoid the constraints on heat dissipation imposed by ambient temperatures, and 2) adaptive changes in Mb and thermal traits may have influenced the geographical distribution and energy-saving strategies of bats. These findings contribute to an understanding of how small endotherms cope with thermal challenges, shedding light on the physiological and evolutionary mechanisms that shape species’ ecological niches and biogeographic patterns across diverse environments.
The habitat breadth of phyllostomid bats is partially determined by their diet and could be used as a predictor of extinction risk
(Springer Nature (Alemania), 2024) Carballo‑Morales, Jorge D.; Villalobos, Federico; Saldaña‑Vázquez, Romeo A.; Herrera‑Alsina, Leonel
Abstract. The tight relationship of niche breadth (i.e., environmental tolerance and resource use) with ecomorphological traits and extinction risk makes the study of habitat niche breadth (i.e., habitat heterogeneity; HB) crucial to understanding the species’ ecological niche and macroecological aspects. Additionally, HB has been associated with the species extinction risk (ER) due to human activity. Bats can be ideal for understanding HB’s ecological and conservation relevance due to their diverse diet and other traits, as well as the high number of threatened species. Here, we studied the association between HB, trophic guild (TG), body mass (BoM), and extinction risk (ER) in phyllostomid bat species using a phylogenetic comparative approach. Our results showed that the TG, not BoM, is significantly associated with HB in phyllostomid bats. Omnivorous and sanguinivorous bats have a wider HB than plant-eating and insectivorous bats. Regarding the ER of bats, our results showed that species without risk have wider HB than species at risk. The HB of species without conservation status does not differ from at-risk species, which suggests that at least some species should be considered at risk. In conclusion, our study suggests that diet is a relevant trait that influences the macroecological dynamic of phyllostomid bats due to its relation with HB. Additionally, we provided evidence supporting HB’s use as an ER predictor. Finally, we discussed the necessity of finding alternative and quicker ways to assess the ER of the species.
Seabirds as biovectors in the transport of plastic debris across ecosystem borders: A case study from the Humboldt Current Upwelling System
(Elsevier (Países Bajos), 2024) Fernández, Claudia E.; Luna-Jorquera, Guillermo; González Encinas, Verónica; Auger Lancelloti, Andrea; Lantadilla, Carlos; Aguilar-Pulido, Roberto; Kiessling, Tim; Knickmeier, Katrin; Varela, Andrea I.; Thiel, Martin
Abstract. Seabirds have become biovectors of plastic pollutants between marine and terrestrial ecosystems, and transport of plastics to their nesting sites becomes relevant due to increasing levels of pollution. To determine the pathways by which plastic reaches their colonies, we analysed the abundance of plastics at the nesting sites of five seabird species (Humboldt penguin Spheniscus humboldti, Peruvian booby Sula variegata, kelp gull Larus dominicanus, grey gull Leucophaeus modestus, Markham's storm-petrel Hydrobates markhami) nesting in northern Chile. Seabirds were primarily grouped according to their nesting behaviour, but two species foraging in contrasting habitats (kelp gull and Markham's storm-petrel) were also compared directly. The abundance, type, and polymer of macro-, meso- and microplastics were analysed in the soil of colonies and control sites, and microplastic ingestion was evaluated for selected species. Densities of plastics in colonies of surface-nesting seabirds ranged from 0 to 21.4 items m−2 (mainly plastic bags and thin films), and 0.002 to 19.7 items m−2 (mainly hard fragments) in colonies of burrow-nesting seabirds. Mean microplastic loads in the stomachs of seabirds were between 3.7 ± 4.2 plastic items individual−1. Overall, the abundances of plastic items in all seabird colonies were low, suggesting a limited transfer of plastics from sea to land. For kelp gulls, the results indicate transfer of macroplastic items to colonies, reaching the colony via regurgitates, with landfills considered as the main plastic source. Our results suggest that contrasting nesting behaviour and foraging habitats among species can explain differential plastic accumulation in seabird colonies, but also other factors, such as wind, contribute to the accumulation of plastic debris in colonies. Proper management of sanitary landfills are key to reduce plastic contamination of coastal seabirds and their colonies.
Monitoring plastic pollution using bioindicators: a global review and recommendations for marine environments
(Royal Society of Chemistry (Reino Unido), 2025) Savoca, Matthew S.; Abreo, Neil Angelo; Arias, Andres H.; Baes, Laura; Baini, Matteo; Bergami, Elisa; Brander, Susanne; Canals, Miquel; Choy, C. Anela; Corsi, Ilaria; De Witte, Bavo; Domit, Camila; Dudas, Sarah; Duncan, Emily M.; Fernández, Claudia E.; Fossi, Maria Cristina; Garcés-Ordóñez, Ostin; Godley, Brendan J.; González-Paredes, Daniel; González Carman, Victoria; Hamilton, Bonnie M.; Hardesty, Britta Denise; Hee Hong, Sang; Kahane-Rapport, Shirel; Kashiwabara, Lauren M.; Baptista Lacerda, Mariana; Luna-Jorquera, Guillermo; Manno, Clara; Nelms, Sarah E.; Panti, Cristina; Pérez-Venegas, Diego J.; Pham, Christopher K.; Provencher, Jennifer F.; Purca, Sara; Rashid, Harunur; Rodríguez, Yasmina; Sparks, Conrad; Sun, ChengJun; Thiel, Martin; Tsangaris, Catherine; Santos, Robson G.
Abstract. Monitoring the movement of plastic into marine food webs is central to understanding and mitigating the plastic pollution crisis. Bioindicators have been a component of the environmental monitoring toolkit for decades, but how, where, and which bioindicators are used in long-term monitoring programs has not yet been assessed. Moreover, these programs have yet to be synthesized and evaluated globally. Doing so is imperative if we are to learn from these pioneering programs and expand on their efforts. We reviewed global monitoring programs using bioindicators that focus on plastic pollution and found 11 worldwide that met our definition of long-term monitoring. Limited data availability and few programs in the Global South hinder progress on tracking global trends. Most commonly, long-term programs either tracked macroplastics with opportunistic sampling of large vertebrates or monitored microplastics with targeted sampling of invertebrates. These long-term bioindicators could be incorporated as essential ocean variables in the global ocean observing system, and thus provide critical insights into the trajectory and effects of plastic pollution on marine ecosystems. However, to enhance the effectiveness and inclusivity of these monitoring efforts, there is a pressing need for the implementation of harmonized and standardized methods, increased collaboration between regions, and greater support for data sharing and open science practices. By addressing these challenges and expanding the geographic scope of monitoring programs, we can better inform evidence-based policies and interventions aimed at mitigating plastic pollution on a global scale.

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