Browsing by Author "Martinez, Javier"

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    A Sarcocystid Misidentified as Hepatozoon didelphydis: Molecular Data from a Parasitic Infection in the Blood of the Southern Mouse Opossum (Thylamys elegans) from Chile
    (2008) Merino, Santiago; Vasquez, Rodrigo A.; Martinez, Javier; Celis-Diez, Juan L.; Martinez-De La Puente, Josue; Marin-Vial, Paula; Sanchez-Monsalvez, Inocencia; Peirce, Michael A.
    The blood of 21 adult South American mouse opossums (Thylamys elegans) captured from April through August of 2005 in central Chile was examined for parasites. Light microscopic analysis of blood smears initially suggested that a highly pleomorphic Hepatozoon species typical of American opossums was infecting erythrocytes. Unexpectedly, amplification by PCR and sequencing of a DNA fragment of the small subunit rDNA combined with phylogenetic analyses indicated that the parasite is not a member of the suborder Adeleorina, which includes the Haemogregarina and Hepatozoon species, but that it is a clearly distinct member of the suborder Eimeriorina, which includes the cyst-forming family Sarcocystidae. Therefore, a reclassification of this unusual intraerythrocytic apicomplexan will require additional life cycle, microscopic, and molecular analyses.
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    Alternating Copolymerization of Epoxides and Anhydrides Catalyzed by Aluminum Complexes
    (2018) de Sarasa Buchaca, Marc Martinez; de la Cruz-Martinez, Felipe; Martinez, Javier; Alonso-Moreno, Carlos; Fernandez-Baeza, Juan; Tejeda, Juan; Niza, Enrique; Castro-Osma, Jose A.; Otero, Antonio; Lara-Sanchez, Agustin
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    Amidinate Aluminium Complexes as Catalysts for Carbon Dioxide Fixation into Cyclic Carbonates
    (2018) Osorio Melendez, Danay; Lara-Sanchez, Agustin; Martinez, Javier; Wu, Xiao; Otero, Antonio; Castro-Osma, Jose A.; North, Michael; Rojas Guerrero, René
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    Approach to Circular Chemistry Preparing New Polyesters from Olive Oil
    (2023) Werlinger, Francisca; Caprile, Renato; Cardenas-Toledo, Valentino; Tarraff, Bastian; Mesias-Salazar, Angela; Rojas, Rene S.; Martinez, Javier; Trofymchuk, Oleksandra S.; Flores, Mario E.
    The transformation of cooking oils and their waste intopolyestersis a challenge for circular chemistry. Herein, we have used epoxidizedolive oil (EOO), obtained from cooking olive oil (COO), and variouscyclic anhydrides (such as phthalic anhydride PA, maleic anhydrideMA, and succinic anhydride SA) as raw materials for the preparationof new bio-based polyesters. For the synthesis of these materials,we have used the bis(guanidine) organocatalyst 1 andtetrabutylammonium iodide (Bu4NI) as cocatalyst. The optimalreaction conditions for the preparation of poly(EOO-co-PA) and poly(EOO-co-MA) were 80 degrees C for 5 husing toluene as solvent; however, the synthesis of poly(EOO-co-SA) required more extreme reaction conditions. Furthermore,we have exclusively succeeded in obtaining the trans isomer for MA-polyester.The obtained biopolyesters were characterized by NMR, Fourier transforminfrared, thermogravimetric analysis, and scanning electron microscopyanalyses. Since there are few examples of functionalized and definedcompounds based on olive oil, it is innovative and challenging totransform these natural-based compounds into products with high addedvalue.
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    Associations among MHC genes, latitude, and avian malaria infections in the rufous-collared sparrow (Zonotrichia capensis)
    (2024) de Aguilar, Juan Rivero; Barroso, Omar; Bonaccorso, Elisa; Cadena, Hector; Hussing, Lucas; Jorquera, Josefina; Martinez, Javier; Martinez-de la Puente, Josue; Marzal, Alfonso; Miranda, Fabiola Leon; Merino, Santiago; Matta, Nubia E.; Ramenofsky, Marilyn; Rozzi, Ricardo; Valeris-Chacin, Carlos E.; Vasquez, Rodrigo A.; Vianna, Juliana A.; Wingfield, John C.
    The major histocompatibility complex (MHC) is a genetic region in jawed vertebrates that contains key genes involved in the immune response. Associations between the MHC and avian malaria infections in wild birds have been observed and mainly explored in the Northern Hemisphere, while a general lack of information remains in the Southern Hemisphere. Here, we investigated the associations between the MHC genes and infections with Plasmodium and Haemoproteus blood parasites along a latitudinal gradient in South America. We sampled 93 rufous-collared sparrows (Zonotrichia capensis) individuals from four countries, Colombia, Ecuador, Peru, and Chile, and estimated MHC-I and MHC-II allele diversity. We detected between 1-4 (MHC-I) and 1-6 (MHC-II) amino acidic alleles per individual, with signs of positive selection. We obtained generalized additive mixed models to explore the associations between MHC-I and MHC-II diversity and latitude. We also explored the relationship between infection status and latitude/biome. We found a non-linear association between the MHC-II amino acidic allele diversity and latitude. Individuals from north Chile presented a lower MHC genetic diversity than those from other locations. We also found an association between deserts and xeric shrublands and a lower prevalence of Haemoproteus parasites. Our results support a lower MHC genetic in arid or semi-arid habitats in the region with the lower prevalence of Haemoproteus parasites.
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    Haematozoa in forest birds from southern Chile
    (2008) Merino, Santiago; Moreno, Juan.; Vasquez, Rodrigo A.; Martinez, Javier; Sanchez-Monsalvez, Inocencia; Estades, Cristian F.; Ippi, Silvina; Sabat, Pablo; Rozzi, Ricardo; Mcgehee, Steven
    The existence of latitudinal gradients in species richness and their abundance is known for many free living organisms but few cases have been reported for parasitic diseases. In addition, asymmetries between the Northern and Southern Hemispheres in several characteristics may affect the distribution and diversity of species at all ecological levels. In this respect, we study the distribution of several genera of blood parasites infecting birds along a latitudinal gradient that includes the world's southernmost forests ecosystems. Birds were mist-netted and sampled for blood in localities across Chile ranging from 33 degrees S to 55 degrees S during the years 2003-06. Overall, 26 bird species were sampled and 27 parasite lineages were identified. The latter belonged to three genera: Plasmodium (8), Haemoproteus (8) and Leucocytozoon (11). We found a positive significant relationship between prevalence and latitude for Leucocytozoon lineages and a negative relationship for Haemoproteus, Plasmodium and mixed infections. However, we did not find a significant relationship between parasite diversity and latitude. We found 18 lineages infecting only one species of host, and 19 lineages appear in only one of the localities of sampling. This pattern implies that some parasite lineages may evolve in isolation in some species/localities. In addition, specificity at the host-family level was only found for Haemoproteus lineages infecting birds in the family Emberizidae. Individuals of the long distance migrant bird white-crested elaenia (Elaenia albiceps), were found infected by the same parasite lineages in localities separated by 20 degrees of latitude. Infections by these lineages were detected in other sedentary birds including juveniles and nestlings of different bird species. Therefore, long distance migrants are able to distort the presence of latitudinal gradients of diseases due to the potential role of migrants in spreading infections. Geographical gradients in prevalence of avian haematozoa differ between parasite genera and hemispheres, probably in relation to the existence of appropriate vector-parasite-host interactions.
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    Highly Active CO2 Fixation into Cyclic Carbonates Catalyzed by Tetranuclear Aluminum Benzodiimidazole-Diylidene Adducts
    (2021) Mesias-Salazar, Angela; Yepes, Yersica Rios; Martinez, Javier; Rojas, Rene S.
    A set of tetranuclear alkyl aluminum adducts 1 and 2 supported by benzodiimidazole-diylidene ligands L-1, N,N'-(1,5-diisopropylbenzodiimidazole-2,6-diylidene)bis(propan-2-amine), and L-2, N,N'-(1,5-dicyclohexyl-benzodiimidazole-2,6-diylidene)dicyclohexanamine were synthetized in exceptional yields and characterized by spectroscopic methods. These compounds were studied as catalysts for cyclic carbonate formation (3a-o) from their corresponding terminal epoxides (2a-o) and carbon dioxide utilizing tetrabutylammonium iodide as a nucleophile in the absence of a solvent. The experiments were carried out at 70 degrees C and 1 bar CO2 pressure for 24 h and adduct 1 was the most efficient catalyst for the synthesis of a large variety of monosubstituted cyclic carbonates with excellent conversions and yields.
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    Molecular characterization of an ancient Hepatozoon species parasitizing the 'living fossil' marsupial 'Monito del Monte' Dromiciops gliroides from Chile
    (2009) Merino, Santiago; Vasquez, Rodrigo A.; Martinez, Javier; Luis Celis-Diez, Juan; Gutierrez-Jimenez, Leticia; Ippi, Silvina; Sanchez-Monsalvez, Inocencia; Martinez-de la Puente, Josue
    The Microbiotheriid Dromiciops gliroides, also known as 'Monito del Monte', is considered to be a threatened species and the only living representative of this group of South American marsupials. During the last few years, several blood samples from specimens of 'Monito del Monte' captured at Chiloe island in Chile have been investigated for blood parasites. Inspection of blood smears detected a Hepatozoon species infecting red blood cells. The sequences of DNA fragments corresponding to small subunit ribosomal RNA gene revealed two parasitic lineages belonging to Hepatozoon genus. These parasite lineages showed a basal position with respect to Hepatozoon species infecting rodents, reptiles, and amphibians but are phylogenetically distinct from Hepatozoon species infecting the order Carnivora. In addition, the Hepatozoon lineages infecting D. gliroides are also different from those infecting other micro-mammals living in sympatry, as well as from some that have been described to infect an Australian species of bandicoot. The potential vector of this parasite appears to be the host-specific tick Ixodes neuquenensis because the sequencing of a long amplicon determined the presence of one of the two lineages found in the marsupial. (C) 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 568-576.
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    New development of a solar electrochemical raceway pond reactor for industrial wastewater treatment
    (ACADEMIC PRESS INC ELSEVIER SCIENCE, 2022) Salazar, Ricardo; Campos, Sebastian; Martinez, Javier; Luna, Francisca; Thiam, Abdoulaye; Aranda, Mario; Calzadilla, Wendy; Miralles-Cuevas, Sara; Cabrera-Reina, Alejandro
    In this work, a solar electrochemical-raceway pond reactor (SEC-RPR) is used to treat textile industrial wastewater by solar photoelectron-Fenton (SPEF) at pilot plant scale for the first time. The SEC-RPR is composed of an electrochemical filter press-cell coupled to RPR, where H2O2 is electro-generated. A complete study about experimental variables such as current, catalyst concentration, pollutant load or liquid depth is conducted based on methyl orange removal, mineralization and decolorization. Validation of the SPEF process using SEC-RPR reached more than 80% of mineralization, as well as the complete decolorization of the solution. The good performance of the SPEF treatment in the new SEC-RPR led to quick degradation kinetics, mainly due to the synergetic action of solar radiation and good distribution of H2O2 electrogenerated in the photoreactor. 100% Methyl Orange degradation was achieved after 150, 60, 45, 30 and 20 min of reaction time applying current density equal to 5, 10, 20, 40 and 60 mA cm(-2), respectively. However, the increase of current density decreased the mineralization current efficiency. Up to 10 aromatics intermediates and 5 short-chain carboxylic acids were identified by LC-MS and HPLC analysis and a reaction pathway for MO mineralization by SPEF is proposed. This study represents an essential preliminary step towards the development of the first SEC-RPR at demo scale.
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    Toward a Neutral Single-Component Amidinate Iodide Aluminum Catalyst for the CO2 Fixation into Cyclic Carbonates
    (2021) Saltarini, Sebastian; Villegas-Escobar, Nery; Martinez, Javier; Daniliuc, Constantin G.; Matute, Ricardo A.; Gade, Lutz H.; Rojas, Rene S.
    A new iodide aluminum complex ({AlI(kappa(4)-naphbam)}, 3) supported by a tetradentate amidinate ligand derived from a naphthalene-1,8-bisamidine precursor (naphbamH, 1) was obtained in quantitative yield via reaction of the corresponding methyl aluminum complex ({AlMe(kappa(4)-naphbam)}, 2) with 1 equiv of I-2 in CH2Cl2 at room temperature. Complexes 2 and 3 were tested and found to be active as catalysts for the cyclic carbonate formation from epoxides at 80 degrees C and 1 bar of CO2 pressure. A first series of experiments were carried out with 1.5 mol % of the alkyl complex 2 and 1.5 mol % of tetrabutylammonium iodide (TBAI) as a cocatalyst; subsequently, the reactions were carried out with 1.5 mol % of iodide complex 3 as a single-component catalyst. Compound 3 is one of the first examples of a nonzwitterionic halide single-component aluminum catalyst producing cyclic carbonates. The full catalytic cycle with characterization of all minima and transition states was characterized by quantum chemistry calculations (QCCs) using density functional theory. QCCs on the reaction mechanism support a reaction pathway based on the exchange of the iodine contained in the catalyst by 1 equiv of epoxide, with subsequent attack of I- to the epoxide moiety producing the ring opening of the epoxide. QCCs triggered new insights for the design of more active halide catalysts in future explorations of the field.