University of Costa Rica

About: University of Costa Rica is a education organization based out in San José, Costa Rica. It is known for research contribution in the topics: Population & Venom. The organization has 9817 authors who have published 16781 publications receiving 238208 citations. The organization is also known as: UCR & Universidad de Costa Rica.

Global phylogeography of the ridley sea turtles (lepidochelys spp.) as inferred from mitochondrial dna sequences

Abstract: The Kemp's ridley sea turtle (Lepidochelys kempi) is restricted to the warm temperate zone of the North Atlantic Ocean, whereas the olive ridley turtle (L. olivacea) is globally distributed in warm-temperate and tropical seas, including nesting colonies in the North Atlantic that nearly overlap the range of L. kempi. To explain this lopsided distribution, Pritchard (1969) proposed a scenario in which an ancestral taxon was divided into Atlantic and Pacific forms (L. kempi and L. olivacea, respectively) by the Central American land bridge. According to this model, the olive ridley subsequently occupied the Pacific and Indian Oceans and recently colonized the Atlantic Ocean via southern Africa. To assess this biogeographic model, a 470 bp sequence of the mtDNA control region was compared among 89 ridley turtles, including the sole L. kempi nesting population and 7 nesting locations across the range of L. olivacea. These data confirm a fundamental partition between L. olivacea and L. kempi (p=0.052-0.069), shallow separations within L. olivacea (p=0.002-0.031), and strong geographic partitioning of mtDNA lineages. The most divergent L. olivacea haplotype is observed in the Indo-West Pacific region, as are the central haplotypes in a parsimony network, implicating this region as the source of the most recent radiation of olive ridley lineages. The most common olive ridley haplotype in Atlantic samples is distinguished from an Indo-West Pacific haplotype by a single nucleotide substitution, and East Pacific samples are distingushed from the same haplotype by two nucleotide substitutions. These shallow separations are consistent with the recent invasion of the Atlantic postulated by Pritchard (1969), and indicate that the East Pacific nesting colonies were also recently colonized from the Indo-West Pacific region. Molecular clock estimates place these invasions within the last 300,000 years.

Clarification and concentration of melon juice using membrane processes

Abstract: Melon juice obtained from fruits discarded by exporters was first clarified by crossflow microfiltration and then concentrated by osmotic evaporation (OE). The resulting clarified melon juice was highly similar to the initial juice, except for insoluble solids and carotenoids, which were concentrated in the retentate. Average permeation flux was relatively high (about 80 L h −1 m −2 ), with continuous extraction of retentate at a volumetric reduction ratio of 3. After concentration of the clarified melon juice to as much as 550 g kg −1 of total soluble solids using a continuous feed-and-bleed procedure of OE, we found that almost the entire composition of the product was preserved. This integrated membrane process permitted two valuable products to be obtained: a clarified concentrate of melon juice that had not undergone any thermal treatment, and a glowing-orange retentate that was enriched in provitamin A. Industrial relevance The increasing quality demand for fresh fruits results in an increase in rejected melons. Juice processing could overcome the product losses occurring but thermal sensitivity of melon juice flavour prohibits conventional thermal processing. Interestingly this paper attempts to use membrane processes for microbial stabilisation and concentration. The authors present a novel way of using permeate (clear juice) as well as retentate (pulpy juice). Enzyme activities in the products during and after processing may need some attention prior to industrial application of the process.

Climate change impacts and adaptation among smallholder farmers in Central America

Abstract: Smallholder farmers are one of the most vulnerable groups to climate change, yet efforts to support farmer adaptation are hindered by the lack of information on how they are experiencing and responding to climate change. More information is needed on how different types of smallholder farmers vary in their perceptions and responses to climate change, and how to tailor adaptation programs to different smallholder farmer contexts. We surveyed 860 smallholder coffee and basic grain (maize/bean) farmers across six Central American landscapes to understand farmer perceptions of climate change and the impacts they are experiencing, how they are changing their agricultural systems in response to climate change, and their adaptation needs. Almost all (95%) of the surveyed smallholder farmers have observed climate change, and most are already experiencing impacts of rising temperatures, unpredictable rainfall and extreme weather events on crop yields, pest and disease incidence, income generation and, in some cases, food security. For example, 87% of maize farmers and 66% of coffee farmers reported negative impacts of climate change on crop production, and 32% of all smallholder farmers reported food insecurity following extreme weather events. Of the farmers perceiving changes in climate, 46% indicated that they had changed their farming practices in response to climate change, with the most common adaptation measure being the planting of trees. There was significant heterogeneity among farmers in the severity of climate change impacts, their responses to these impacts, and their adaptation needs. This heterogeneity likely reflects the wide diversity of socioeconomic and biophysical contexts across smallholder farms and landscapes. Our study demonstrates that climate change is already having significant adverse impacts on smallholder coffee and basic grain farmers across the Central American region. There is an urgent need for governments, donors and practitioners to ramp up efforts to help smallholder farmers cope with existing climate impacts and build resiliency to future changes. Our results also highlight the importance of tailoring of climate adaptation policies and programs to the diverse socioeconomic conditions, biophysical contexts, and climatic stresses that smallholder farmers face.

Antimicrobial Activity of Necklace Orchids is Phylogenetically Clustered and can be Predicted With a Biological Response Method.

Abstract: Necklace orchids (Coelogyninae, Epidendroideae) have been used in traditional medicine practices for centuries. Previous studies on a subset of unrelated orchid species utilized in these traditional practices revealed they possessed antimicrobial, anti-inflammatory, and anti-oxidant activity, providing experimental proof for their medicinal properties. To date however none of these species have been investigated ethno-botanically in a phylogenetic context. This study carried out comparative bioprospecting for a group of wild orchids using EBDCS (the Economic Botany Data Collection Standards) organ targeted and biological response methods. The traditional medicinal use of necklace orchids was recorded from books and journals published between 1984 and 2016. Two orchids, Coelogyne cristata and Coelogyne fimbriata, were selected, cultivated both indoors and outdoors, and the antimicrobial properties on extracts from their leaves and pseudobulbs tested against a selection of human pathogens. A molecular phylogeny of Coelogyninae based on nuclear ribosomal ITS and plastid matK DNA sequences obtained from 148 species was reconstructed with Maximum Likelihood (ML) using RAxML, Maximum Parsimony (MP) using PAUP and Bayesian Inference using MrBayes. Bioprospecting comparison of EBDCS and biological response was carried out using customized R scripts. Ethanolic extracts obtained from leaves of C. fimbriata inhibited growth of Bacillus cereus, Staphylococcus aureus, and Yersinia enterocolitica, confirming the antimicrobial properties of these extracts. Leaf extracts were found to have slightly stronger antimicrobial properties for plants cultivated outdoors than indoors. These differences were not found to be statistically significant though. Three hot nodes with high potency for antimicrobial activities were detected with the EBDCS organ targeted classification method, and eight hot nodes were detected with the biological response classification method. The biological response classification method is thus a more effective tool in finding hot nodes amongst clades of species with high medicinal potential.