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  Subjects -> SCIENCES: COMPREHENSIVE WORKS (Total: 374 journals)
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UNED Research Journal / Cuadernos de Investigación UNED
Number of Followers: 1  

  This is an Open Access Journal Open Access journal
ISSN (Online) 1659-441X
Published by Universidad Estatal a Distancia Homepage  [6 journals]
  • First pages 16 (Jan-Dec 2024)

    • Authors: UNED Research Journal
      Pages: e5171 - e5171
      PubDate: 2024-02-08
      DOI: 10.22458/urj.v16i1.5171
      Issue No: Vol. 16 (2024)
       
  • Zoonotic and non-zoonotic gastrointestinal parasites in frogs from an
           urban tropical river of Costa Rica

    • Authors: Gabriela Pérez-Gómez, Ana Eugenia Jiménez-Rocha
      Pages: e4803 - e4803
      Abstract: Introduction: The urban ecosystems of Costa Rica are home to several anuran species that coexist with still poorly studied parasites. Objective: To report the presence of zoonotic and non-zoonotic gastrointestinal parasites in Hyalinobatrachium fleischmanni, Espadarana prosoblepon, Smilisca sordida, in urban river habtat in San José, Costa Rica. Methods: We analyzed 30 fecal samples, from specimens kept in the laboratory for ten months, with three diagnostic techniques. Results: We detected for the first time in Costa Rica the presence of Giardia duodenalis and Cryptosporidium parvum in H. fleischmanni, E. prosoblepon and S. sordida (with antigen detection tests); in addition, nematodes (Strongylidae and Rhabdias spp.), intestinal ciliates and cestode eggs with other diagnostic techniques. Conclusion: These urban frogs carried at least six types of parasites, some of them, first reports.
      PubDate: 2023-12-21
      DOI: 10.22458/urj.v16i1.4803
      Issue No: Vol. 16 (2023)
       
  • Electroactive microorganisms in coffee processing wastewater (iron redox
           processes)

    • Authors: Joice Castro Alvarez, Lidieth Uribe Lorío , Paola Fuentes-Schweizer
      Pages: e4806 - e4806
      Abstract: Introduction: Wastewater is often a good source for electrogenic bacteria, which are essential for Microbial Fuel Cells (MFCs). The electrons they release while metabolizing organic matter is evidence of their electrogenic capacity. Objective: To evaluate the iron-reducing capacity of bacteria isolated from coffee wastewater. Methods: We isolated morphologically distinct facultative bacteria from the anode electrode of MFCs, with coffee mill wastewater as our substrate. We did a preliminary identification with the Biolog GEN III system (Biolog Inc. Hayward, CA, USA). To assess the conversion of iron (III) to iron (II) by the isolated bacteria, we tested iron (III) citrate, iron (III) chloride, and iron (III) oxide. For comparison, we used S. oneidensis as a positive control in our experiments. Results: We identified eight bacterial isolates with a predominance of non-sporulated Gram positive bacilli morphology. They have reductive activity of iron compounds, giving the best conversion percentages from a for iron oxide (III). The isolate coinciding with the genus Citrobacter (SB), the only Gram negative bacillus, obtained iron conversion percentages higher than 1,0% in the three iron compounds (maximum: 4,3%). Conclusion: In the residual water from the coffee process, there are bacteria with electrogenic capability that could be used in Microbial Fuel Cells.
      PubDate: 2023-12-21
      DOI: 10.22458/urj.v16i1.4806
      Issue No: Vol. 16 (2023)
       
  • Crustaceans in Phragmatopoma sp. (Polychaeta: Sabellariidae) intertidal
           reefs, Pacific, Costa Rica

    • Authors: José A. Vargas, Rita Vargas-Castillo, Jeffrey A. Sibaja-Cordero
      Pages: e4926 - e4926
      Abstract: Introduction: Annelid polychaete worms of the family Sabellariidae build reefs by cementing together sand grains. These reefs increase local habitat heterogeneity and species diversity. The reefs are used as a refuge by invertebrates, and crustaceans are frequent. Objective: To list the species of crustaceans found in Phragmatopoma sp. reefs on two localities of the North Pacific coast of Costa Rica and at the port of Puntarenas, Gulf of Nicoya estuary. Methods: We dislodged fragments of reef colonies qualitatively at low tide with a chisel, stored them in plastic bags and later disaggregated the fragments by hand. We identified the crustaceans whenever possible and deposited them in the collection at the University of Costa Rica (MZUCR). Results: We identified 30 species: 26 species of macro-crustaceans in samples from the North coast, eight of them Petrolisthes (Porcellanidae). From the Puntarenas samples we identified five species (27 macro-crustaceans and 3 isopods). A few micro-crustaceans (Amphipoda, Isopoda) were also present but not identified. Conclusions: The number of crustacean species found in Phragmatopoma sp. reefs is relatively high but comparisons with other studies are difficult. Porcellanid crabs are common on these reefs. The low diversity of Puntarenas reefs remains unexplained.
      PubDate: 2023-12-08
      DOI: 10.22458/urj.v16i1.4926
      Issue No: Vol. 16 (2023)
       
  • Chemical profile of essential oils of the Costa Rican native tree
           Myrcianthes storkii (Myrtaceae)

    • Authors: Carlos Chaverri, José F. Cicció
      Pages: e4863 - e4863
      Abstract: Introduction: The genus Myrcianthes ranges from southern Florida to Chile, including the Caribbean, and the species Myrcianthes storkii is a shrub or tree found in Costa Rica and western Panama, in wet to very rainy, cloud, and oak forests (altitude 1300-3150m). Objective: To identify the chemical composition of essential oils from leaves, floral buds, and twigs of M. storkii of Costa Rica. Methods: We obtained the essential oils through hydrodistillation in a Clevenger-type apparatus. The chemical composition of the oils was done by GC/FID and GC/MS, using the retention indices on DB-5 and Carbowax types of capillary columns in addition to mass spectra. Results: The oils consisted mainly of terpenoids (55,45-87,75%). A total of 281 compounds accounted for 91,27-74,56% of the total amount of oils. The major constituents from the leaf oil were myrcene (17,44%), cis-calamenene (12,60%), α-pinene (5,48%), (E)-caryophyllene (5,16%), limonene (3,91%), p-cymene (3,71%), 1,8-cineole (2,80%), and α-humulene (2,80%). The floral bud essential oil consisted mainly of α-pinene (15,23%), cis-calamenene (12,70%), myrcene (8,59%), 1,8-cineole (4,26%), germacrene B (3,65%), α-humulene (3,55%), and (E)-caryophyllene oxide (2,93%). The major components of twig oil were cis-calamenene (11,31%), palmitic acid (7,99%), (E)-caryophyllene (4,68%), -cadinene (3,28%), cubenol (3,24%), and (Z)-caryophyllene oxide (2,94%). Conclusion: The presence of a significant quantity of myrcene and cis-calamenene seems to be characteristic of this species.
      PubDate: 2023-12-08
      DOI: 10.22458/urj.v16i1.4863
      Issue No: Vol. 16 (2023)
       
 
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