Publicaciones académicas

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Esta colección incluye artículos de profesores de la Pontificia Universidad Católica de Chile, publicados en revistas nacionales y extranjeras.

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Now showing 1 - 20 of 606

2000 years of agriculture in the Atacama desert lead to changes in the distribution and concentration of iron in maize
(Nature Research, 2021) Ale V.E.; Fernanda P.M.; Ale V.E.; Nathalia N.; Hannetz R.; Mauricio U.; Kevin R.; Frédéric G.; Christian D.
© 2021, The Author(s).We performed a histological and quantitative study of iron in archaeological maize seeds from prehispanic times recovered from Tarapacá, Atacama Desert. Also, we examined iron distribution changes at the cell level in embryos from ancient versus new varieties of maize. Our results show a progressive decrease in iron concentration from the oldest maize to modern specimens. We interpret the results as an effect of prehispanic agriculture over the micronutrient composition of maize.
3G extruded snacks enriched with catechin for high antioxidant capacity
(Taylor and Francis, 2024) Zambrano Y.; Mariotti-Celis M.S.; Bouchon P.
© 2023 The AuthorsExtrusion yields either an expanded product or a non-expanded pellet. Non-expanded pellets undergo subsequent indirect expansion in a separate thermal device, such as a microwave oven, resulting in a third-generation (3G) snack. The utilization of milder conditions, makes this an encouraging approach for functional food development. Currently, the effects of both processes on retaining functional ingredients and the evolution of their structure are not yet fully understood. Accordingly, this work aimed to analyze how extrusion temperature (110, 135, and 150 °C) and moisture content (27 and 31%) affect the physical characteristics of 3G expanded rice-flour products enriched with catechins, using a microstructural approach, to better understand the relationship between catechin retention, antioxidant capacity, and structure development. The results showed that products with catechin exhibited higher expansion and increased crispiness/crunchiness, with a relatively higher percentage of small pores, as revealed by X-ray microtomography. Additionally, there was a remarkable retention of catechin and antioxidant capacity (DPPH) in the expanded products, reaching nearly 100%. The preservation of antioxidant capacity in the expanded products may be attributed to the high-temperature-short-time process, which favors catechin stability, along with the dense glassy structure of the extruded pellets obtained, protecting them through encapsulation until their subsequent expansion.
A composite transcriptional signature differentiates responses towards closely related herbicides in Arabidopsis thaliana and Brassica napus
(2010) Das, M.; Gutiérrez Ilabaca, Rodrigo Antonio
A Feasible Approach to Developing Fiber-Enriched Bread Using Pomegranate Peel Powder: Assessing Its Nutritional Composition and Glycemic Index
(2023) García, Paula; Bustamante, Andrés; Echeverría González, Francisca Cecilia; Encina, Cristian; Palma, Manuel; Sanhueza, Leyla; Sambra, Verónica; Pando, Maria Elsa; Jiménez, Paula
The consumption of dietary fiber (DF) has been associated with a reduced incidence of non-communicable diseases. Despite various strategies implemented worldwide to increase DF intake, it remains low. Therefore, the development of new fiber-rich food products that are widely consumed could be a strategy to improve DF intake. In this study, an agro-industrial by-product, pomegranate peel powder (PPP), was used as an innovative source of DF and antioxidant. The objective was to develop a bread enriched with DF, antioxidants, and sensory characteristics by partially replacing wheat flour (WF) with PPP at levels of 0%, 2.5%, 5%, 7.5%, and 10%. Bread with 2.5% and 5% PPP was chosen for a clinical trial to evaluate glycemic response (GR) in healthy subjects and determine the bread’s glycemic index (GI). As the percentage of PPP increased, both the DF and total polyphenol content increased significantly. The highest overall acceptability was achieved with bread containing up to 5% PPP. Consumption of bread with 2.5% and 5.0% PPP significantly reduced the GI compared to the control bread, while the decrease in GR was not significant. PPP could be a potential food and low-cost ingredient to improve the bread’s nutritional quality through its contribution to DF and antioxidants.
A holistic view of nitrogen acquisition in plants
(2011) Kraiser Miranda, Tatiana Diannela; Gutiérrez Ilabaca, Rodrigo Antonio
A modeling approach to determining the relationship between vegetative filter strip design and sediment composition
(2017) Lobo, G.; Bonilla Meléndez, Carlos Alberto; CEDEUS (Chile)
A molecular framework for the inhibition of Arabidopsis root growth in response to boron toxicity
(2012) Aquea Zeballos, José Felipe; Vega C., Andrea; Jullian Fabres, Pastor; Arce Johnson, Jorge Patricio
A multipurpose portable instrument for determining ripeness in wine grapes using NIR spectroscopy
(IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2008) Larrain, Manuel; Guesalaga, Andres R.; Agosin, Eduardo
This paper describes the development of a noninvasive instrument that is designed to measure three parameters of ripeness in wine grapes, i.e., sugar (Brix), pH, and anthocyanin concentration. The instrument is based on near-infrared spectroscopy, and it comes in contact with the berry in the cluster without altering its ripening process. A thorough description of the calibration process for the instrument is done for the different grape varieties, e.g., Cabernet Sauvignon, Carmenere, Merlot, Pinot Noir, and Chardonnay. Samples from vineyards located in the Maipo Valley (Chile) taken during the 2003 season were processed to develop calibration models using partial least squares techniques. The models were validated in terms of root mean square error of validation and R-2 indices. The results show the great potential of this technique regarding Brix and pH measurements. For the anthocyanin concentration measurements, the results are promising but require an accurate procedure to obtain reference values for model calibration. The instrument can be useful for sampling strategies that look for optimum harvest schedules according to grape maturity in terms of not only sugar content but also pH and anthocyanin concentration.
A new method of assessing water erosion risk in forest operations based on rainfall variability
(UNIV AUSTRAL CHILE, FAC CIENCIAS FORESTALES, 2012) Contreras, Juan; Bonilla, Carlos A.; Troncoso, Juan
Water erosion has been a major environmental problem associated to forest harvesting operations in humid and temperate climates. The incorporation of this factor in the decision making process has been complex due to the high variability observed in rainfall intensity and magnitude. This paper presents a methodology for incorporating the temporal variability of rainfall in the planning of forest operations. We used a monthly index based on the R-RUSLE erosivity factor. This index allows knowing the most likely value of soil loss and associating a confidence level. Thus, the forest planner has an estimate of erosion rates related to the operations, and an index that reflects the rainfall variability. With this methodology it is possible to identify, for a given level of soil loss, those months in which there is a higher uncertainty. This methodology was applied to a pine plantation in Santa Barbara, Biobio Region, Chile, where the rainfall erosivity ranges from 16 MJ mm ha(-1) h(-1) to 271 MJ mm ha(-1) h(-1) depending on the month of the year.
A new species of Pseudococcus (Hemiptera: Pseudococcidae) belonging to the "Pseudococcus maritimus" complex from Chile: molecular and morphological description
(MAGNOLIA PRESS, 2011) Correa, Margarita; Aguirre, Carlos; Germain, Jean Francois; Hinrichsen, Patricio; Zaviezo, Tania; Malausa, Thibaut; Prado, Ernesto
A new species of mealybug from Chile, Pseudococcus meridionalis Prado sp. n., is described and illustrated based on the morphological and molecular characterization of adult females. This species belongs to the "Pseudococcus maritimus" complex and displays a wide host plant range, including Japanese pear, persimmon, pomegranate, pear and grape.
A non-destructive digital imaging method to predict immobilized yeast-biomass
(ELSEVIER, 2009) Acevedo, Cristian A.; Skurtys, Olivier; Young, Manuel E.; Enrione, Javier; Pedreschi, Franco; Osorio, Fernando
In food fermentation, many types of immobilization systems are used, such as hydrogel entrapment, where alginate is the main biopolymer. one of the important problems in industrial processes is the quantifications of biomass, since the traditional system of direct cell counting cannot be used. In this study, a simple digital imaging method to determine the biomass of yeasts immobilized into alginate capsules was developed. Important evidence of the yeasts growing inside the alginate was the change in the surface color of the capsule. Digital images were taken with different biomass concentration, and the RGB-analysis showed significant differences in the blue field. The histogram of the blue channel was used to develop a PLS multivariate calibration to predict biomass concentration. The method was validated in primary beer fermentation with good efficiency. (C) 2009 Elsevier Ltd. All rights reserved.
A randomized trial of a screening, case finding, and referral system for older veterans in primary care
(WILEY, 2007) Rubenstein, Laurence Z.; Alessi, Cathy A.; Josephson, Karen R.; Hoyl, M. Trinidad; Harker, Judith O.; Pietruszka, Fern M.
OBJECTIVES: To test whether a system of screening, assessment, referral, and follow-up provided within primary care for high-risk older outpatients improves recognition of geriatric conditions and healthcare outcomes.
A rapid, sensitive and inexpensive method for detection of grapevine red blotch virus without tissue extraction using loop-mediated isothermal amplification
(2019) Romero, J. L.; Carver, G. D.; Arce Johnson, Jorge Patricio; Perry, K. L.; Thompson, J. R.
A remarkable synergistic effect at the transcriptomic level in peach fruits doubly infected by prunus necrotic ringspot virus and peach latent mosaic viroid
(2013) Herranz, Mari C.; Niehl, Annette; Rosales V., Marlene; Fiore, Nicola; Zamorano, Alan; Granell, Antonio; Pallas, Vicente
Abstract Background Microarray profiling is a powerful technique to investigate expression changes of large amounts of genes in response to specific environmental conditions. The majority of the studies investigating gene expression changes in virus-infected plants are limited to interactions between a virus and a model host plant, which usually is Arabidopsis thaliana or Nicotiana benthamiana. In the present work, we performed microarray profiling to explore changes in the expression profile of field-grown Prunus persica (peach) originating from Chile upon single and double infection with Prunus necrotic ringspot virus (PNRSV) and Peach latent mosaic viroid (PLMVd), worldwide natural pathogens of peach trees. Results Upon single PLMVd or PNRSV infection, the number of statistically significant gene expression changes was relatively low. By contrast, doubly-infected fruits presented a high number of differentially regulated genes. Among these, down-regulated genes were prevalent. Functional categorization of the gene expression changes upon double PLMVd and PNRSV infection revealed protein modification and degradation as the functional category with the highest percentage of repressed genes whereas induced genes encoded mainly proteins related to phosphate, C-compound and carbohydrate metabolism and also protein modification. Overrepresentation analysis upon double infection with PLMVd and PNRSV revealed specific functional categories over- and underrepresented among the repressed genes indicating active counter-defense mechanisms of the pathogens during infection. Conclusions Our results identify a novel synergistic effect of PLMVd and PNRSV on the transcriptome of peach fruits. We demonstrate that mixed infections, which occur frequently in field conditions, result in a more complex transcriptional response than that observed in single infections. Thus, our data demonstrate for the first time that the simultaneous infection of a viroid and a plant virus synergistically affect the host transcriptome in infected peach fruits. These field studies can help to fully understand plant-pathogen interactions and to develop appropriate crop protection strategies.Abstract Background Microarray profiling is a powerful technique to investigate expression changes of large amounts of genes in response to specific environmental conditions. The majority of the studies investigating gene expression changes in virus-infected plants are limited to interactions between a virus and a model host plant, which usually is Arabidopsis thaliana or Nicotiana benthamiana. In the present work, we performed microarray profiling to explore changes in the expression profile of field-grown Prunus persica (peach) originating from Chile upon single and double infection with Prunus necrotic ringspot virus (PNRSV) and Peach latent mosaic viroid (PLMVd), worldwide natural pathogens of peach trees. Results Upon single PLMVd or PNRSV infection, the number of statistically significant gene expression changes was relatively low. By contrast, doubly-infected fruits presented a high number of differentially regulated genes. Among these, down-regulated genes were prevalent. Functional categorization of the gene expression changes upon double PLMVd and PNRSV infection revealed protein modification and degradation as the functional category with the highest percentage of repressed genes whereas induced genes encoded mainly proteins related to phosphate, C-compound and carbohydrate metabolism and also protein modification. Overrepresentation analysis upon double infection with PLMVd and PNRSV revealed specific functional categories over- and underrepresented among the repressed genes indicating active counter-defense mechanisms of the pathogens during infection. Conclusions Our results identify a novel synergistic effect of PLMVd and PNRSV on the transcriptome of peach fruits. We demonstrate that mixed infections, which occur frequently in field conditions, result in a more complex transcriptional response than that observed in single infections. Thus, our data demonstrate for the first time that the simultaneous infection of a viroid and a plant virus synergistically affect the host transcriptome in infected peach fruits. These field studies can help to fully understand plant-pathogen interactions and to develop appropriate crop protection strategies.
A salicylic acid-induced lectin-like protein plays a positive role in the effector-triggered immunity response of arabidopsis thaliana to pseudomonas syringae Avr-Rpm1
(2013) Armijo, Grace; Salinas Salvo, Paula Andrea Ximena; Monteoliva, María Inés; Seguel, Aldo; García, Consuelo; Villarroel Candia, Eva; Song, Wei; Van Der Krol, Alexander Ronald; Álvarez, María Elena; Holuigue Barros, María Loreto
A Severe Outbreak of Charcoal Rot in Cantaloupe Melon Caused by Macrophomina phaseolina in Chile
(2013) Jacob Grez, Cristián Jascha; Krarup Hjort, Christian Frederik; Díaz Ulloa, Gonzalo Alberto; Latorre G., Bernardo
A sexually dimorphic hypothalamic response to chronic high-fat diet consumption
(2016) Morselli, Eugenia; Frank A.; Palmer B.; Rodriguez-Navas C.; Criollo A.; Clegg D.
A simple model for estimating changes in rainfall erosivity caused by variations in rainfall patterns
(2018) Lobo, Gabriel P.; Bonilla Meléndez, Carlos Alberto
A Systems Approach Uncovers Restrictions for Signal Interactions Regulating Genome-wide Responses to Nutritional Cues in Arabidopsis
(2009) Krouk, G.; Gutiérrez Ilabaca, Rodrigo Antonio
A systems view of nitrogen nutrient and metabolite responses in Arabidopsis
(2008) Vidal Olate, Elena Alejandra; Gutiérrez Ilabaca, Rodrigo Antonio

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