CAPTURA. Repositorio Academico de la Universidad de Chile
(5.176 recursos)
Captura almacena y conserva la producción de conocimiento generado por docentes e investigadores de la Universidad de Chile, y la hace visible desde los portales académicos internacionales.
Mostrando recursos 1 - 20 de 33
1.
Dung decomposition and associated beetles in a fragmented temperate forest - Bustamante Sánchez, Marcela A.; Grez, Audrey A.; Simonetti, Javier A.
Habitat fragmentation may result in changes in species number and Population abundance among habitats that differ in area, structure, or edge characteristics. These changes, in turn, may result in alterations in ecosystem process such as decomposition of organic matter. Through an experimental approach, we compared the beetles assemblages associated with dung and decomposition of cow feces in a continuous portion of Maulino forest, forest fragments and in pine plantations that surround this forest and forest remnants. Abundance and richness of dung-associated beetles were lower in forest fragments compared to the continuous forest and pine plantations. However, dung decomposition was similar...
2.
Functional and structural optimization of the respiratory system of the bat Tadarida brasiliensis (Chiroptera, Molossidae): does airway geometry matter? - Canals, Mauricio; Atala, Cristian; Olivares, Ricardo; Guajardo, Francisco; Figueroa, Daniela; Sabat, Pablo; Rosenmann, Mario
We studied structure and function of the respiratory system in the bat Tadarida brasifiensis and compared it with those of two species of rodents, Abrothrix andinus and A. olivaceus. Tadarida brasiliensis had lower resting oxygen consumption, but higher maximum oxygen consumption and aerobic scope, than the rodents. The blood-gas barrier of the bat was thinner and its relative lung size was larger; however, alveolar surface density was similar among the three species. In consequence, T. brasiliensis has an oxygen diffusion capacity two or three times higher than that of the rodents. In Tadarida brasiliensis the characteristics of the lung were...
3.
Effects of forest fragmentation on the granivory of differently sized seeds - Donoso, Denise S.; Grez, Audrey A.; Simonetti, Javier A.
The Maulino forest is a unique temperate ecosystem restricted to a small range of the coast of central Chile. This forest harbors many endemic species, and is threatened due to intensive deforestation and fragmentation. Currently the Maulino forest is composed of a suite of small fragments scattered in a landscape dominated by exotic plantations. The fragmentation of the Maulino forest has resulted in a higher abundance of granivores in small forest fragments compared with continuous forest. In order to determine if fragmentation-induced changes in granivore abundance affects the granivory of different size seeds, we experimentally assessed seed predation of a...
4.
Evaluation of an imported dicalcium phosphate in broiler chicks - Cornejo, Sergio; Pokniak, José; González, J.; Salazar, J.; Contreras, E.
The chemical composition and biological value of two dicalcium phosphates, a dihydrated one (FA) and a mollohydrated product (FB), were assessed in a 2 x 3 factorial arrangement of treatments: two phosphates (A and B) and three levels of available P (aP) in the diets (0.22, 0.31 and 0.49%). One hundred and ninety two day-old male broiler chicks (Hubbard) were distributed between 6 treatments with 4 replicates each. During the experimental period (1-42 days), the birds were fed 2 diets: "starter" (1 to 21 days) and "finisher" (22 to 42 days). Feed and water were supplied ad libitum. The phosphates...
5.
Short-term effects of habitat fragmentation on the abundance and species richness of beetles in experimental alfalfa microlandscapes - Grez, Audrey A.; Zaviezo, Tania; Reyes, Susana
Habitat loss and fragmentation are considered as the main causes of biodiversity depression. Habitat loss implies a reduction of suitable habitat for organisms, and habitat fragmentation is a change in the spatial configuration of the landscape, with the remaining fragments resulting more or less isolated. Recent theory indicates that the effects of habitat loss are more important than those of habitat fragmentation, however there are few experimental studies evaluating both processes separately. To test the effects of habitat fragmentation per se on the abundance, species richness and diversity of epigeal coleopterans, 15 (30 x 30 m) alfalfa microlandscapes, distributed in...
6.
Presencia de Bartonella henselae en gatos: cuantificación del reservorio natural y riesgo de exposición humana de esta zoonosis en Chile - Ferrés, Marcela; Abarca, Katia; Godoy, Paula; García, Patricia; Palavecino, Elizabeth; Méndez, Gabriela; Valdés, Alicia; Ernst, Santiago; Thibaut, Julio; Koberg, Jurgen; Chanqueo, Leonardo; Vial, Pablo
Background: The availability of a serologic test for cat scratch disease in humans has allowed the diagnosis of an increasing number of cases of this disease in disease in Chile. Aim: To perform a serological survey for Bartonella henselae among cats in Chile. Material and methods: Blood samples from 187 cats living in three Chilean cities were obtained. IgG and methods. Blood samples from 187 cats living in three Chilean, cities were obtained. IgG antibodies against Bartonella henselae were measured using indirect immunofluorescence. Blood cultures were clone in 60 samples. The presence of Bartonella henselae in positive cultures was confirmed...
7.
Mechanisms affecting population density in fragmented habitat - Tischendorf, Lutz; Grez, Audrey A.; Zaviezo, Tania; Fahrig, Lenore
We conducted a factorial simulation experiment to analyze the relative importance of movement pattern, boundary-crossing probability, and mortality in habitat and matrix on population density, and its dependency on habitat fragmentation, as well as inter-patch distance. We also examined how the initial response of a species to a fragmentation event may affect our observations of population density in post-fragmentation experiments. We found that the boundary-crossing probability from habitat to matrix, which partly determines the emigration rate, is the most important determinant for population density within habitat patches. The probability of crossing a boundary from matrix to habitat had a weaker,...
8.
Trypanosoma cruzi infection in wild mammals from a chagasic area of Chile - Rozas, Marlene; Botto-Mahan, Carezza; Coronado, Ximena; Ortiz, Sylvia; Cattan, Pedro E.; Solari, Aldo
We report results of PCR-DNA based detection of Trypanosoma cruzi in wild mammal reservoirs from a chagasic area of Chile. We analyzed 157 blood samples from wild mammals including the marsupial Thylamis elegans and the rodents Octodon degus, Phyllotis darwini, and Abrothrix olivaceus. In addition, 42 blood samples from goats (i.e., a peridomestic mammal) were analyzed. Blood samples were used to extract DNA, and PCR was performed using the amplification of minicircle DNA sequences. Southern analysis was used to confirm diagnosis with a universal probe of p(32) -labeled kinetoplast DNA. Altogether, 51% of the wild and 36% of the peridomestic...
9.
Experimental infection of Leishmania (L.) chagasi in a cell line derived from Lutzomyia longipalpis (Diptera : Psychodidae) - Bello, Felio; Mejía, Astrid; Corena, María del Pilar; Ayala, Martha; Sarmiento, Ladys; Zúñiga, Claudio; Palau, María
The present work describes the in vitro infection of a cell line Lulo, derived from Lutzomyia longipalpis embryonic tissue, by Leishmania chagasi promastigotes. This infection process is compared with a parallel one developed using the J774 cell line. The L. chagasi MH/CO/84/CI-044B strain was used for experimental infection in two cell lines. The cells were seeded on glass coverslips in 24-well plates to reach a final number of 2x10(5) cells/well. Parasites were added to the adhered Lulo and J774 cells in a 10:1 ratio and were incubated at 28 and 37 degrees C respectively. After 2 4, 6, 8, and...
10.
Selective crystallization of calcium salts by poly (acrylate)-grafted chitosan - Neira Carrillo, Andrónico; Yazdani Pedram, M.; Retuert de la Torre, Jaime; Díaz Dosque, Mario; Gallois, Sebastien; Arias Bautista, José Luis
The biopolymer chitosan was chemically modified by grafting polyacrylamide or polyacrylic acid in a homogeneous aqueous phase using potassium persulfate (KPS) as redox initiator system in the presence of N,N-methylene-bis-acrylamide as a crosslinking agent. The influence of the grafted chitosan on calcium salts crystallization in vitro was studied using the sitting-drop method. By using polyacrylamide, grafted chitosan as substrate, rosette-like CaSO4 crystals were observed. This was originated by the presence of sulfate coming from the initiator KPS. By comparing crystallization on pure chitosan and on grafted chitosan, a dramatic influence of the grafted polymer on the crystalline habit of both...
11.
Biomimetic processes through the study of mineralized shells - Arias Bautista, José Luis; Fernández, M. S.
Fabrication of mineralized structures is a widespread phenomenon among living organisms (e.g., shells, carapaces, spines, spicules, bones and teeth). These ceramic biocomposites consist of layered assemblies of minute amounts of macromolecules with well-ordered calcium-rich inorganic phases, resulting in the formation of products of unique morphologies and properties. The characterization of the mechanisms controlling the processes of biomineralization is crucial for the development of novel materials with desirable shape and texture properties. In previous reports on eggshells and mollusk and crustacean shells, we have studied the cell-shell interactions, the crystalline microstructure of the inorganic component, the localization of particular macromolecules and...
12.
Isolation and molecular characterization of quinolone resistant Salmonella spp. from poultry farms - San Martín, B.; Lapierre, L.; Toro, C.; Bravo, V.; Cornejo, J.; Hormazábal, J. C.; Borie, C.
The antimicrobial susceptibility of 94 Salmonella strains isolated from different poultry farms in Chile (broiler and laggin hens) were analyzed by the dilution plates method. Thirty-nine of them were resistant to flumequine, nalidixic acid and oxolinic acid with MIC values higher than 64 mu g/ml. These quinolone resistant strains were analyzed in order to determine the presence of mutations in the QRDR region of gyrA gene by AS-PCR-RFLP analysis. 51.3% of the strains showed mutations at codon Ser 83 and 41.0% showed mutations at codon Asp 87. No mutations were observed on codon Gly 81. These mutations were confirmed by...
13.
Localization of osteopontin in oviduct tissue and eggshell during different stages of the avian egg laying cycle - Fernández, M. S.; Escobar, C.; Lavelin, I.; Pines, M.; Arias Bautista, José Luis
The avian eggshell is an acellular bioceramic containing organic and inorganic phases that are sequentially assembled during the time the egg moves along the oviduct. As it has been demonstrated in other mineralized tissues, mineralization of the eggshell is regulated by extracellular matrix proteins especially the anionic side chains of proteoglycans. Among them, osteopontin has been found in the avian eggshell and oviduct. However, its precise localization in the eggshell or in different oviduct regions during eggshell formation, nor its function have been established. By using anti-osteopontin antibody (OPN 1), we studied its immunolocalization in the isthmus, red isthmus and...
14.
Effect of human chorionic gonadotrophin supplementation during different culture periods on in vitro maturation of canine oocytes - Reyes, Mónica De los; Lange, Johanna de; Miranda, Pedro; Palominos, Jaime; Barros, Claudio
he IVM of canine oocytes is characterized by low rates of metaphase H. The objective of this study was to evaluate the effects of hCG on mciotic development of canine oocytes for culture periods up to 96 h. Oocytes were collected after ovariohysterectomy. Only oocytes > 110 mu m in diameter, with a homogeneous dark cytoplasm and three or more layers of compact cumulus cells were used. For IVM, the COCs were cultured in TCM-199 + 10% fetal calf serum, without (medium A control) or supplement with 10 IU/mL of hCG (medium B), or with a combination of both media...
17.
Contenido de glicosaminoglicanos, aldehídos y proteínas en el líquido sinovial de la articulación metacarpofalángica equina normal y alterada - Adarmes, H.; Croxatto, A.; Galleguillos, M.; González, E.
The purpose of this study was to evaluate the influence of severity of osteoarthritis on the concentration of degradation products from the cartilage extracellular matrix on synovial fluid. Total protein and aldehyde group concentrations were determined as indicators of collagen degradation. The concentration of glycosaminoglycans (GAGs) in sinovial liquid was also determined, both the total amount (GAGsT) and the fractions corresponding to the GAGs other than hyaluronic acid or sulfated GAGs (GAGsG), that consist mostly of chondroitin and keratin sulfate. The hyaluronic acid content of the synovial fluid was calculated as the difference between the concentrations of GAGsT and GAGsS....
18.
Primer hallazgo de vectores de la enfermedad de Chagas asociados a matorrales silvestres en la Región Metropolitana, Chile - Bacigalupo B., Antonella; Segura M., José A.; García C., Alejandro; Hidalgo C., Javier; Galuppo G., Stephania; Cattan, Pedro E.
Background: Insects of the subfamily triatominae are the biological
vectors of Trypanosoma cruzi, the causal agent of Chagas disease. Aim: To search for wild colonies of
triatomines in the Metropolitan Region of Chile. Material and Methods: Ad hoc traps were placed in
two endemic zones of the Metropolitan Region of Chile, during 30 nights. The dejections of 16 T infestans
and 43 M spinolai specimens were examined under the microscope, searching for live metacyclic
trypomastigotes. A polymerase chain reaction (PCR) was performed in macerates of all insects looking
for T cruzi DNA. Results: A total of 269 bugs were captured. Forty four were Triatoma infestans and
225...
19.
Efecto de la edad sobre el tamaño de los proteoglicanos del cartílago articular equino - Adarmes, H.; Aracena, L.; Galleguillos, M.; González, E.
The aim of this study was to evaluate the effect of age on proteoglycans size in equine articular cartilage. Cartilage samples were obtained from metacarpophalangeal joints of crossbred equines inmediatelly after slaughter, and alloted in three groups according to the equine's age: 1.5-2 years (n = 7); 4-5 years (n = 6) and over 10 years (n = 4). The cartilage extracts (100 mg /pair joints) were pooled for each age group and fractionated by exclution and ion exchange gel chromatography. Proteoglycan content of each fraction was determined by colorimetric reaction with safranine-O. The elution profile of Sepharose CL-2B, showed...
20.
Proacrosin/acrosin quantification as an indicator of acrosomal integrity in fresh and frozen dog spermatozoa - Cortés, Constanza J.; Codelia, Verónica A.; Manosalva, Iris; Lange, Johanna de; Reyes, Mónica de los; Moreno, Ricardo D.
The scope of the present study was to evaluate the presence and activation of proacrosin/acrosin as a tool to determine the acrosomal status of fresh and frozen/thawed dog spermatozoa. Monoclonal antibody C5F11, directed against human acrosin, cross-reacted with dog spermatozoa and labeled the acrosome of both fresh and frozen/thawed dog spermatozoa. Frozen/thawed spermatozoa had a lesser proportion of labeled spermatozoa than fresh spermatozoa (P < 0.05). When live spermatozoa were labeled with soybean trypsin inhibitor conjugated with Alexa 488 (SBTI-Alexa 488), the proportion of acrosome-labeled fresh spermatozoa was less than frozen/thawed spermatozoa (P < 0.05). By using Western blots and...
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