Escuela de Ciencias Ambientales

URI permanente para esta comunidadhttp://10.0.96.45:4000/handle/11056/14682

La Escuela de Ciencias Ambientales (EDECA) de la Universidad Nacional contribuye con la sociedad costarricense y de otras naciones, especialmente centroamericanas, a forjar un desarrollo humano con mejores relaciones entre el ambiente y la sociedad, mediante la formación de profesionales competitivos y con una visión holística, en los campos de las ciencias forestales, educación ambiental y gestión del ambiente. Desde sus áreas estratégicas, la EDECA se posesiona en campos emergentes dentro de éstas, con enfoques holísticos y que tienen repercusión e impacto regional, tales como los servicios ambientales, la certificación forestal, los mercados alternativos y el desarrollo local, la gestión del ambiente y la gestión empresarial.

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A botanical extract of Souroubea sympetala and its active principle, betulinic acid, attenuate the cortisol response to a stressor in rainbow trout, Oncorhynchus mykiss
(Elsevier, 2016-09-28) Mullally, Martha; Mimeault, Caroline; Otárola Rojas, Marco Antonio; Sanchez Vindas, Pablo; Garcia, Mario; Poveda Alvarez, Luis; Moon, Thomas W.; Gilmour, Kathleen M.; Trudeau, Vance; Arnason, John
The capacity of the traditional anxiolytic plant, Souroubea sympetala, and its bioactive principle, betulinic acid (BA), to lower cortisol levels in rainbow trout, Oncorhynchus mykiss, was investigated. Effects at the level of the cortisol-producing interrenal cells were investigated using an in vitro head kidney preparation. Head kidney tissue incubated with S. sympetala extract or BA produced significantly less cortisol in response to adrenocorticotropic hormone (ACTH) than cells incubated with ACTH alone; a 50% reduction in the cortisol response was predicted to occur at 43 μg mL− 1 extract or 71 μg mL− 1 BA. To investigate whether effects on interrenal cell cortisol production translated into effects at the whole-animal level, the plasma cortisol response to an acute stressor, confinement in a net, was assessed. Fish fed a commercial trout pellet diet supplemented with 1 mg kg− 1 fish BA for six days exhibited a significantly lower plasma cortisol response to the acute stressor than fish fed the unsupplemented diet. Collectively, these results demonstrate that S. sympetala and BA act on the interrenal cells of the hypothalamic-pituitary-interrenal (HPI) axis in rainbow trout to significantly attenuate the cortisol response to an acute stressor. These findings suggest that BA is of potential use in mitigating effects of exposure to the stressors commonly encountered in an aquaculture setting. Statement of relevance • Souroubea sympetala extract and betulinic acid reduced ACTH-stimulated cortisol production by head kidney tissue in vitro, with little or no evidence of cytotoxicity.• The cortisol response to an acute stressor was attenuated in rainbow trout fed a commercial diet supplemented with betulinic acid.• The cortisol-reducing properties of the S. sympetala extract and betulinic acid may be useful in mitigating effects of stress in aquaculture, particularly since, as natural products, they may raise less public concern with respect to human consumption.
Altitudinal zonation of montane Quercus forests along two transects in Chirripó National Park, Costa Rica
(Springer, 1995-08) Kappelle, Maarten; Van Uffelen, Jan-Gerrit; Cleef, Antoine
Abiotic and vegetation data were collected along two altitudinal transects through mature montane Quercus forests on the Pacific and Atlantic slopes of Costa Rica's Chirripó Massif. Between 2000 and 3200 m asl twenty-four 0.05 ha forest plots were selected at altitudinal intervals of 100 m, and eight soil profiles were described at intervals of 200 m. A TWINSPAN classification aided in the determination of eight zonal forest communities on the basis of their floristic composition. They are grouped in two sets of four: (i) the palm-rich lauraceous-fagaceous Lower Montane Mollinedia-Quercus Forests (2000-2600 m asl) and (ii) the bamboo-rich myrsinaceous-fagaceous Upper Montane Schefflera-Quercus Forests (2500-3200 m asl), respectively. Vegetation changes seem correlated with two major climatic gradients: (i) a temperature gradient (altitude), and (ii) a moisture gradient (wet Atlantic vs. moist Pacific slope). Most soils are Andepts, and residual, colluvial or derived from volcanic material. Humus layers are thicker on the wetter Atlantic slope. A total of 431 vascular plant species consisted of 86 pteridophytes, 1 gymnosperm, 296 dicots and 48 monocots. Species richness, canopy height and stem diameter decrease with increasing altitude, while the canopy surface becomes more flattend. A comparison with other studies shows that Chirripó's montane Quercus forests fit within the environmental ranges known from altitudinal zonations elsewhere in the Tropics. © 1995 Kluwer Academic Publishers.
Anti-inflammatory and antinociceptive activities of Loasa speciosa in rats and mice
(Elsevier, 2003) Badilla Baltodano, Beatriz; Arias, A. Y.; Arias, M.; Mora, G. A.; Poveda Alvarez, Luis
In the range of doses of 250–500 mgykg (given i.p.) the aqueous extract of Loasa speciosa leaves showed an inhibitory effect on leukocyte migration, and a reduction on the pleural exudate, as well as dose-dependent anti-inflammatory and peripheral antinociceptive activities.
Blown by the wind: the ecology of male courtship display behavior in orchid bees
(Ecological Society of America, 2017-02-01) Pokorny, Tamara; Vogler, Ira; Losch, René; Schlütting, Patrick; Juarez, Pedro; Bissantz, Nicolai; Ramirez, Santiago; Eltz, Thomas
Many insects rely on chemical signals to transmit precise information on the location, identity, and quality of potential mates. Chemical signals are often broadcasted at sites with physical properties that maximize signal propagation and signal transmission. Male neotropical orchid bees (Euglossini) perch and display on vertical branches and tree trunks in the forest to expose volatile blends (perfumes) that they previously collected from their environment. Previous studies have shown that the chemical composition of perfume blends is highly differentiated even between closely related species. However, variation in behavioral components of perfume exposure and male display remain poorly understood. We conducted a four-year study on orchid bee display sites (8 species) in pacific Costa Rica, using field observations along with chemical analysis and cage experiments to assess display niche partitioning among sympatric species. We evaluated the influence of physical factors (terrain, wind, light) on the distribution of perch sites and on display behavior, and tested a prediction of the sex pheromone-analogue hypothesis, i.e., that displaying males have above-average quantities or qualities of acquired perfumes. Males of different species displayed in the same general area and sometimes in close proximity to each other, but partitioned the display niche by selecting different perch diameters, display heights, and by displaying at different times of the day. Most perch sites were located inside the forest on elevated ground, especially along ridges, where stronger winds may help disperse perfume signals. Furthermore, the angular position of displaying males on perches was narrowly determined by wind direction, with males being positioned on the downwind side of the perch, where they would be most conspicuous to conspecifics approaching on an odor trail. Although our results generally support the hypothesis that perfumes serve as pheromone analogues, we did not find differences in the perfume composition of males caught at display perches and males captured at chemical baits. This suggests that, while chemical communication is an integral part of orchid bee display, male display activity is not determined by the history of, and success in, volatile acquisition. © 2017 by the Ecological Society of America
Crecimiento inicial de una plantación mixta de Quercus, Cornus, Alnus y Cupressus en Costa Rica
(Universidad Nacional, Costa Rica., 1996) Chaverri, Adelaida; Zúñiga, Edwin; Fuente, Anael
Tbe growth of an eleven year old, míxed plantation Qf four native tree species (Quercus seemannii, Q. . pitarius, Comus disciflora and Alnus acuminata) and an exotic species (Cupressus lusitanica) was studied in San José de la Montafia, Heredia, Costa Rica. C. lusitanica had the Iargest diameter (23.46 cm), and A. acuminata, the greatest height (22.08 m). Q. pitarius had the 10west diameter growth rate (0.52 cm/yr), C. lusitanica showed the highest diameter growth rate (2.13 cm/yr) while C. disciflora had a medium growth rate (1.28 cm/yr). Tbe best architectural qualities were seen in A. acuminata and C. lusitanica, followed by C. disciflora. Growthand . IifChitectural data @ow that Iiglít intolerant species A. acuminata and C. lusitanica grow well in míxed p1antati9!ls. Slower growing oales, known as tolerant species, need more Iight. Tbinning· operations around or before age seven 1ü"é recornmended, especially lo iinprove growth of Quercus species.
Ethnobotany of immunomodulatory treatments used by the Q’eqchi’ Maya of Belize
(Springer Nature Link, 2019-04-25) Walshe-Roussel, Brendan; Otarola Rojas, Marco; Sánchez Vindas, Pablo; Pesek, Todd; Cal, Víctor; Arnason, John
Using a quantitative ethnobotanical methodology, we identified 107 plant species belonging to 49 families used by Q’eqchi’ Maya healers in the treatment of symptoms from 14 usage categories related to inflammation. The families with the largest number of medicinal species were Piperaceae, Araceae, Asteraceae, Fabaceae, and Adiantaceae with five or more medicinal species. Healer consensus for plant species was high, with 56 species (52%) being used by all the healers, and consensus for usage categories was also high, as informant consensus factor (FIC) values for each category were greater than 0.4.
Ethnopharmacology of Souroubea sympetala and Souroubea gilgii (Marcgraviaceae) and identification of betulinic acid as an anxiolytic principle
(Elsevier, 2015-05) Puniani, Eva; Cayer, Christian; Kent, Pamela; Mullally, Martha; Sánchez-Vindas, Pablo; Poveda Álvarez, Luis; Cal, Victor; Merali, Zul; Arnason, John; Durst, Tony
The neotropical lianas Souroubea gilgii and Souroubea sympetala (Marcgraviaceae) were chosen for study as part of a phytochemical discovery strategy focusing on rare plant families in Central America. In participatory research, Q’eqchi’ healers in Belize reported the use of these plants to reverse psychological symptoms inflicted by witchcraft. Extracts of two Souroubea species showed significant anti-anxiety activity in the elevated plus maze, a standardized test paradigm. Bioassay guided isolation led to the active principle, the pentacyclic triterpene, betulinic acid, which had activity in the elevated plus maze at 0.5 mg/kg. Other phytochemicals isolated included α- and β-amyrin, 2-hydroxyursolic acid, taraxenyl trans-4-hydroxy-cinnamate, naringenin, methyl ursolate, eriodytiol, methyl 2-α-hydroxyursolate, methyl 2-α-hydroxymaslinate, methyl betulinate, and condrilla sterol.
Hypoglycemic and antihyperglycemic effect of Witheringia solanacea in normal and alloxan-induced hyperglycemic rats
(Elsevier, 2011) Herrera, Cristina; García Barrantes, Pedro M.; Binns, Franklin; Vargas, Marianela; Poveda, Luis Jorge; Badilla, Sandra
Witheringia solanacea is a small shrub that belongs to the Solanaceae family. The plant is used as an antidiabetic in Costa Rican herbal medicine. The aim of this study was to evaluate the hypoglycemic and antihyperglycemic activity of the aqueous extract of W. solanacea leaves in rodent models. About the materials and methods, a crude extract of W. solanacea leaves was prepared in boiling water and the aqueous filtrate was lyophilized. A single oral dose of 250, 500 and 1000 mg/kg of the extract was evaluated for hypoglycemic activity in a glucose tolerance test in normal rats and for antihyperglycemic activity in alloxan-induced (140 mg/kg) diabetic rats. The blood glucose level was determined at different times by the glucose oxidase method. It Result in a Dosage of 500 and 1000 mg/kg of the extract significantly decreased (p < 0.05) blood glucose levels in the glucose tolerance test in normal rats after 1 h, there was no significant difference observed at 250 mg/kg. Dose of 500 mg/kg of the extract significantly reduced (p < 0.05) blood glucose levels in alloxan induced hyperglycemic rats at 4 and 5 h. In Conclusion, in the present study, the hypoglycemic and antihyperglycemic potential of the W. solanacea was demonstrated in rats. These results give support to the traditional use of W. solanacea as antidiabetic herbal medicine.
Phenolic variation among Chamaecrista nictitans subspecies and varieties revealed through UPLC-ESI(-)-MS/MS chemical fingerprinting
(Springer New York LLC, 2019-02) Chavarría, Max; Quirós‑Guerrero, Luis; Albertazzi, Federico; Araya‑Valverde, Emanuel; Romero, Rosaura M; Villalobos, Heidy; Poveda, Luis; Tamayo-Castillo, Giselle
Introduction Comparative analysis of metabolic features of plants has a high potential for determination of quality control of active ingredients, ecological or chemotaxonomic purposes. Specifically, the development of efficient and rapid analytical tools that allow the differentiation among species, subspecies and varieties of plants is a relevant issue. Here we describe a multivariate model based on LC–MS/MS fingerprinting capable of discriminating between subspecies and varieties of the medicinal plant Chamaecrista nictitans, a rare distributed species in Costa Rica. Methods Determination of the chemical fingerprint was carried out on a LC–MS (ESI-QTOF) in negative ionization mode, in detected and putatively identified compounds included proanthocyanidin oligomers, several flavonoid C- and O-glycosides, and flavonoid acetates. Principal component analysis (PCA), partial least square-discriminant analysis (PLS-DA) and cluster analysis of chemical profiles were performed. Results Our method showed a clear discrimination between the subspecies and varieties of Chamaecrista nictitans, separating the samples into four fair differentiated groups: M1=C. nictitans ssp. patellaria; M2=C. nictitans ssp. disadena; M3=C.nictitans ssp. nictitans var. jaliscensis and M4=C. nictitans ssp. disadena var. pilosa. LC–MS/MS fingerprint data was validated using both morphological characters and DNA barcoding with ITS2 region. The comparison of the morphological characters against the chemical profiles and DNA barcoding shows a 63% coincidence, evidencing the morphological similarity in C. nictitans. On the other hand, genetic data and chemical profiles grouped all samples in a similar pattern, validating the functionality of our metabolomic approach. Conclusion The metabolomic method described in this study allows a reliably differentiation between subspecies and varieties of C. nictitans using a straightforward protocol that lacks extensive purification steps.
Screening of Costa Rican Trichilia species for biological activity against the larvae of Spodoptera litura (Lepidoptera : Noctuidae)
(Elsevier Science Ltd, 2001-04) Wheeler, Deborah A.; Isman, Murray B.; Sanchez Vindas, Pablo; Arnason, John T.
Crude methanolic extracts made from the twigs of 39 plant samples from six species of Trichilia collected in Costa Rica, were incorporated into arti®cial diet and fed to neonate Spodoptera litura larvae. All six plant species tested signi®cantly reduced larval growth after 7 and 10 days. The most active species was T. americana, reducing growth, on average, to 3.9% of control at 1000 ppm fresh weight. The least active, on average, was T. glabra. A twig extract of T. americana proved to be more active than wood, bark or leaf extracts, with the twigextract reducing growth of S. litura larvae by 50% (EC50) at a dietary concentration of 17.2 ppm. When T. americana wood extract was incorporated into arti®cial diet (10, 25, 50 and 75 ppm) and fed to S. litura larvae throughout larval development, growth was slowed and the nal weight of pupae and adults was reduced. At higher extract concentrations (50 and 75 ppm) larvae entered one or two supernumerary instars before pupation occurred. This was shown to be due to both starvation and to post-ingestive activity of the extract.
The life cycle carbon balance of selective logging in tropical forests of Costa Rica
(Wiley Periodicals, 2020-06-01) Alice-Guier, Federico E.; Mohren, Frits; Zuidema, Pieter A.
The effect of logging on atmospheric carbon concentrations remains highly contested, especially in the tropics where it is associated to forest degradation. To contribute to this discussion, we estimated the carbon balance from logging natural tropical forests in Costa Rica through a life cycle accounting approach. Our system included all major life cycle processes at a regional level during one rotation period (15 years). We used mass flow analysis to trace biogenic carbon. Data were gathered from all logging operations in the Costa Rican NWregion (107 management plants), a sample of industries transforming wood into final products (20 sawmills), and national reports. We estimated a surplus of −3.06 Mg C ha−1 15 year−1 stored within the system. When accounting for uncertainty and variability in a MonteCarlo analysis, the average balance shifted to −2.19 Mg C ha−1 15 year−1 with a 95% CI of −5.26 to 1.86. This confidence interval reveals probabilities of a net increase in atmospheric carbon due to harvesting although these are smaller than those from a system that acts as a reservoir. Our results provide evidence for the carbon neutrality of bio-materials obtained from natural forests. We found that anthropogenic reservoirs play a determinant role in delaying carbon emissions and that these may explain differences with previous carbon balance studies on tropical forest management. Therefore, the climate mitigation potential of forest-derived products is not exclusive to forest management, but measures should be considered throughout the processes of wood transformation, use, and disposal.
Two New 3,4-Seco-ent-kaurenes and Other Constituents from the Costa Rican Endemic Species Croton megistocarpus
(Helvetica Chimica Acta, 2011-10) Mora Vasquez, Soledad; Castro, Victor; Poveda, Luis; Chavarría, Max; Murillo, Renato
Following our phytochemical studies of Costa Rican plants, we report the isolation of two new 3,4- seco-ent-kaurenes from the aerial parts of Croton megistocarpus (Euphorbiaceae). The structures of the two compounds were elucidated as 14-[(2-methylbutanoyl)oxy]-3,4-seco-ent-kaura-4(19),16-dien-3-oic acid (1) and 14-{[(2Z)-2-methylbut-2-enoyl]oxy}-3,4-seco-ent-kaura-4(19),16-dien-3-oic acid (2). In addition, seven known diterpene clerodanes were also isolated and identified. The structures of the compounds were elucidated by spectroscopic methods, including HR-MS, 1H-NMR, 13C-NMR, COSY, HMQC, HMBC, and NOESY experiments.

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