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Rare occurrence of only female flowers suggests a lack of sexual reproduction and potential clonality of the seagrass Halophila baillonii Asch. on the Pacific coast of Costa Rica
(2024-09-19) Samper Villarreal, Jimena
Halophila baillonii Asch. is a rare seagrass species found in the Caribbean, Atlantic, and Eastern Tropical Pacific (ETP). It is listed as Vulnerable in the IUCN Red List yet very little is known about its dispersal mechanisms. For this study, samples were collected at five sites on the Pacific coast of Costa Rica. Each site was visited once between 2019 and 2021 as part of a larger molecular study. At each site, H. baillonii foliar shoots were manually collected along three transects. Presence of flowers or fruits was assessed for 1292 foliar shoots using a dissecting microscope. Additionally, sediment samples were collected to assess seed density at three of the sites. Flowering frequency was very low overall (0.7 %), flowers were only found at two of the five sites, and only female flowers were present. There were no fruits or seeds at any of the sites. This is the first report of H. baillonii flowering on the Pacific coast of Costa Rica and within the ETP. Meanwhile, H. baillonii flowers of both sexes and fruits have been found from limited sampling efforts at multiple sites in the Caribbean and Brazil. The findings of this study suggest a lack of sexual reproduction and potential clonality of the seagrass H. baillonii on the Pacific coast of Costa Rica. This supports the recent notion that H. baillonii is the first non-native seagrass in the ETP, yet more detailed field and molecular studies are needed.
Inhibición de los efectos coagulante, fosfolipasa A2 y proteolítico del veneno de Bothrops asper por plantas usadas tradicionalmente en Centroamérica
(2017-12-31) Saravia Otten, Ingrid Patricia; Hernández Hernández, Rosario Damáris; Marroquín Tintí, María Nereida; García, Gabriela; Mérida, Max; Cruz Velásquez, Sully Margot; Orozco Godínez, Irma Nohemí; Cáceres, Armando; Gutiérrez, José María
Existen pocos estudios científicos que demuestren el valor terapéutico de las plantas en la medicina tradicional centroamericana para tratar el envenenamiento ofídico. En este estudio se evaluó la capacidad de los extractos etanólicos de nueve plantas de uso etnomédico en Centroamérica (Acacia hindsii, Aristolochia maxima, Bursera simaruba, Cissampelos pareira, Eryngium foetidum, Hamelia patens, Pimenta dioica, Piper peltatum y Sansevieria hyacinthoides) para inhibir el efecto coagulante del veneno de Bothrops asper. Tres de ellas (B. simaruba, E. foetidum y P. dioica) también fueron evaluadas en cuanto a su capacidad inhibitoria de los efectos fosfolipasa A2 (PLA2) y proteolítico del veneno. Las plantas fueron colectadas en Guatemala, secadas, extraídas con etanol y los efectos inhibitorios evaluados in vitro después de preincubar concentraciones variables de extracto con concentraciones fijas de veneno. Los resultados demostraron que ninguno de los extractos logró inhibir los efectos coagulante y PLA2, pero los extractos clorofilados de P. dioica y E. foetidum inhibieron efectivamente la actividad proteolítica del veneno. El tamizaje fitoquímico, mediante ensayos macro y semimicrométricos de cromatografía en capa fina, demostró la presencia de metabolitos secundarios reportados con actividad antiproteolítica (flavonoides, antocianinas, catequinas y taninos) en la composición química de los extractos de E. foetidum y P. dioica. Su efecto sobre el veneno se evaluó mediante electroforesis SDS-PAGE, demostrándose que no está mediado por degradación proteolítica de los componentes del veneno. El aislamiento y caracterización específica de sus metabolitos secundarios en futuros estudios, permitirá determinar el mecanismo de acción inhibitoria ejercido por estos extractos.
Manual jurídico sobre derechos sexuales y reproductivos [2025]
(2025-11-17) Cordero Molina, Sofía
Video de participación de las VI jornadas de investigación del Instituto de Investigaciones Jurídicas (IIJ) de la Universidad de Costa Rica. Conferencia "Manual jurídico sobre derechos sexuales y reproductivos" por la Dra. Sofía Cordero Molina con el objetivo de sistematizar la normativa y jurisprudencia vigente en Costa Rica para facilitar el acceso a la información jurídica sobre derechos sexuales y reproductivos, tanto para profesionales como para la ciudadanía. Se detalla el proceso de elaboración de una herramienta pedagógica y jurídica sobre derechos sexuales y reproductivos, abordando el marco conceptual de derechos sexuales y reproductivos, la revisión y análisis de la normativa, sistematización jurisprudencial y refelexión sobre el biopoder.
Strengths and challenges of δ15N to identify anthropogenic nutrient loading in coastal systems
(2020-09-02) Samper Villarreal, Jimena
Coastal ecosystems are under increasing stress from anthropogenic nutrient loading; which is most often assessed through water quality measurements. Here, 136 published studies on the use of δ15N to identify nutrient loading in coastal systems were analyzed to identify key strengths and challenges when using this isotope technique. δ15N has been used successfully for this purpose around the globe for over 40 years. Studies have mainly used benthic macroalgae and sediment samples in estuaries and coral reefs of North America and Oceania. Strengths of this technique include timely identification of nutrient loading and its sources, even when inputs are pulsed or assimilated by biota, the benefits of varying isotope turnover rates in different types of samples, sporadic sampling efforts, simple collection and preparation of samples, and relatively low analysis costs. The shortcomings of this technique have led to a loss in popularity in recent times, mainly from isotopic overlap of potential sources and the effects of other confounding factors on isotopic compositions. These challenges can be compensated by simultaneous measurement of other key variables including additional isotopes (δ13C, δ34S), water column nutrient concentrations, and fecal coliforms, highlighting great potential to use this tool.
Dermonecrosis caused by a spitting cobra snakebite results from toxin potentiation and is prevented by the repurposed drug varespladib
(2024-04-30) Bartlett, Keirah E.; Hall, Steven Robert; Rasmussen, Sean A.; Crittenden, Edouard; Dawson, Charlotte A.; Albulescu, Laura Oana; Laprade, William Michael; Harrison, Robert A.; Saviola, Anthony J.; Modahl, Cassandra M.; Jenkins, Timothy Patrick; Wilkinson, Mark C.; Gutiérrez, José María; Casewell, Nicholas R.
Snakebite envenoming is a neglected tropical disease that causes substantial mortality and morbidity globally. The venom of African spitting cobras often causes permanent injury via tissue-destructive dermonecrosis at the bite site, which is ineffectively treated by current antivenoms. To address this therapeutic gap, we identified the aetiological venom toxins responsible for causing local dermonecrosis. While cytotoxic three-finger toxins were primarily responsible for causing spitting cobra cytotoxicity in cultured keratinocytes, their potentiation by phospholipases A2 toxins was essential to cause dermonecrosis in vivo. This evidence of probable toxin synergism suggests that a single toxin-family inhibiting drug could prevent local envenoming. We show that local injection with the repurposed phospholipase A2-inhibiting drug varespladib significantly prevents local tissue damage caused by several spitting cobra venoms in murine models of envenoming. Our findings therefore provide a new therapeutic strategy to more effectively prevent life-changing morbidity caused by snakebite in rural Africa.