Oyarzun R.,University of La Serena |
Oyarzun J.,University of La Serena |
Fairley J.P.,University of Idaho |
Nunez J.,University of La Serena |
And 4 more authors.
Journal of Arid Environments | Year: 2017
A practical approach for the assessment of surface water and groundwater resources in rain-fed midmountain domains of arid to semi-arid zones is much needed, especially in rural areas for which groundwater is the only reliable and permanent water supply source. This is the case in the Coquimbo region (29°150- 32°100 S latitude) of north-central Chile, where groundwater is needed for human consumption but also for agricultural and mining activities at a small to medium scale. This paper examines the usefulness of community knowledge, as encoded in the historical record, for identifying water resources. The existing record of wells and springs in the Coquimbo region is used as a guide to the identification and characterization of structural patterns that may influence the distribution of water resources. The proposed approach combines simple graphical, statistical and geostatistical methods to identify patterns, likely related to local and regional structural controls that influence the distribution of groundwater resources. In the Coquimbo area, these influences tend to align in NW and NE orientations that approximately coincide with regional geological trends. The methodology presented has the potential to form a first step in the search for additional water resources in the Coquimbo region, and may be useful for targeting detailed field studies on the basis of community and historical knowledge in many arid and semi-arid rural areas. © 2017 Elsevier Ltd.
Reversible in vivo cellular changes occur during desiccation and recovery: Desiccation tolerance of the resurrection filmy fern Hymenophyllum dentatum cav [Cambios celulares reversibles observados in vivo durante la desecación y recuperación: Tolerancia a la desecación del helecho película de resurrección Hymenophyllum dentatum Cav]
Bravo S.,Andrés Bello University |
Parra M.J.,San Sebastián University |
Castillo R.,University of Concepción |
Sepulveda F.,Andrés Bello University |
And 6 more authors.
Gayana - Botanica | Year: 2016
The present work explores in vivo physiological, morphological and chemical features during full hydration, desiccation and rehydration of the filmy fern Hymenophyllum dentatum with two main objectives: 1) to get further insight about the mechanisms underlying its desiccation tolerance, and 2) to understand how this plant manages mechanical stress induced by water loss and recovery. With these purposes, physiological (relative water content and Fv/Fm chlorophyll fluorescence parameter), morphological (Confocal Laser Scanning Microscopy and 3D reconstruction) and chemical (FTIR microspectroscopy) data were obtained and compared between fully hydrated, desiccated and rehydrated tissues of H. dentatum. Remarkable changes in cell architecture and chemical composition were observed in vivo in desiccated leaves. Cells were smaller, showed a collapsed general appearance, and were delimitated by apparently folded cell walls. Marked changes in chloroplasts location and decrease in the number of active chloroplasts were also evidenced. Chemical experiments showed that changes in the secondary structure of proteins and in the polysaccharide composition of the cell wall occur in desiccated cells. All changes were rapidly reversed upon rehydration. This study shows that H. dentatum presents an extreme case of desiccation tolerance, able to withdraw severe, rapid and consecutive dehydration/rehydration induced stress by the function of constitutive systems of protection and reparation, in which cell wall folding plays a relevant role as a protective system against mechanical and oxidative stress. Besides, H. dentatum is proposed as an excellent plant model for the study of dissection tolerance such as one cell layer fern, auto-fluorescence of cellular compartments, and simple long term storage under laboratory conditions, among others. © 2017, Universidad de Concepcion. All rights reserved.
Almanza V.,University of Concepción |
Almanza V.,Barrio Universitario |
Parra O.,University of Concepción |
Bicudo C.E.M.,Institute Botanica |
And 4 more authors.
Gayana - Botanica | Year: 2016
The phytoplankton community of three eutrophic shallow lakes located in the same geographical area was compared over a period of three years. Although these lakes are similar in many respects (e.g. location, origin, average depth, high concentration of nutrients, human influence) develop very different phytoplankton communities. Lo Galindo is dominated by Zygnematophyceae, Cyanophyceae and Chlorophyceae, while in Lo Méndez the groups Dinophyceae and Bacillariophyceae and in Las Tres Pascualas the Chlorophyceae, Cryptophyceae and Euglenophyceae. In Lo Mendez and Lo Galindo are frequent blooms of different groups of algae (cyanobacteria, green algae, diatoms and dinoflagellates), which generated wealth increases at different times of the year, even in winter they were presented. In Las Tres Pascualas blooms were rare. The occurrence and frequency of blooms of species representatives of the M, C,Y and Lo functional groups, and VII, VI, IV and V morphological groups, reflect the eutrophic lakes, being indicative of the degree of contamination of these systems that influence their present and future use. © 2017, Universidad de Concepcion. All rights reserved.
Chaigneau A.,Laboratoire Doceanographie Et Of Climatologie Experimentation Et Analyse Numerique |
Chaigneau A.,Instituto Del Mar Of Peru |
Chaigneau A.,Laboratoire dEtudes en Geophysique et Oceanographie Spatiale |
Le Texier M.,CNRS Institute of Fluid Mechanics of Toulouse |
And 3 more authors.
Journal of Geophysical Research: Oceans | Year: 2011
The mean vertical structure of mesoscale eddies in the Peru-Chile Current System is investigated by combining the historical records of Argo float profiles and satellite altimetry data. A composite average of 420 (526) profiles acquired by Argo floats that surfaced into cyclonic (anticyclonic) mesoscale eddies allowed constructing the mean three-dimensional eddy structure of the eastern South Pacific Ocean. Key differences in their thermohaline vertical structure were revealed. The core of cyclonic eddies (CEs) is centered at ∼150 m depth within the 25.2-26.0 kg m-3 potential density layer corresponding to the thermocline. In contrast, the core of the anticyclonic eddies (AEs) is located below the thermocline at ∼400 m depth impacting the 26.0-26.8 kg m-3 density layer. This difference was attributed to the mechanisms involved in the eddy formation. While intrathermocline CEs would be formed by instabilities of the surface equatorward coastal currents, the subthermocline AEs are likely to be shed by the subsurface poleward Peru-Chile Undercurrent. In the eddy core, maximum temperature and salinity anomalies are of ±1°C and ±0.1, with positive (negative) values for AEs (CEs). This study also provides new insight into the potential impact of mesoscale eddies for the cross-shore transport of heat and salt in the eastern South Pacific. Considering only the fraction of the water column associated with the fluid trapped within the eddies, each CE and AE has a typical volume anomaly flux of ∼0.1 Sv and yields to a heat and salt transport anomaly of ±1-3 × 1011 W and ±3-8 × 103 kg s-1, respectively. Copyright 2011 by the American Geophysical Union.
Ciudad G.,University of the Frontier |
Rubilar O.,University of the Frontier |
Azocar L.,University of the Frontier |
Toro C.,Barrio Universitario |
And 4 more authors.
Journal of Bioscience and Bioengineering | Year: 2014
Microalgae can produce and contain lipids, proteins and carbohydrates, which can be extracted and marketed as potential novel added-value bio-products. However, microalgae cell wall disruption is one of the most important challenges involved while processing this type of biomass. In this context, white-rot fungi, responsible for the biodegradation of lignin present in wood due to non-specific extracellular enzymes, could be applied for promoting microalgae cell wall degradation. Therefore, the aim of this study was to evaluate the use of an enzymatic extract produced by the white-rot fungi Anthracophyllum discolor as a biotechnological tool for Botryococcus braunii cell wall disruption. The fungus was inoculated in wheat grains and manganese peroxidase (MnP) activity was monitored while obtaining the enzymatic extract. Then, cell wall disruption trials with different MnP activity were evaluated by the biochemical methane potential (BMP). In relation to cell wall disruption, it was observed that the optimal value was obtained with enzymatic concentration of 1000U/L with a BMP of 521mL CH4/g VS. Under these conditions almost 90% of biomass biodegradability was observed, increasing in 62% compared to the microalgae without treatment. Therefore, the results indicate that enzymes secreted by A. discolor promoted the attack of the different cell wall components finally weakening it. Therefore, the application of this treatment could be a promissory biotechnological approach to decrease the energetic input required for the cell wall disruption step. © 2013 The Society for Biotechnology, Japan.
Cancino J.,University of Concepción |
Cancino J.,Barrio Universitario |
Acuna E.,University of Concepción |
Espinosa M.,University of Concepción
Forest Science | Year: 2013
This article presents a general conceptual framework for seven methods of estimating the height to a given age by stem analysis, which involves estimates of periodical annual increment in height. To estimate the height, a fraction of the periodical increment in height, which is cumulated in a time fraction of the respective period, is assigned to every hidden tip. Traditional methods of height estimation in stem analysis can be grouped into two broad sets, depending on how the time fraction associated with every hidden tip is determined. By combining time fractions from both groups, two mixed methods were derived and compared with traditional methods to determine the most advantageous method under variations in the crosscut intensity and regularity along the stem and variations in the regularity of current annual increments in total height and stem radius throughout the tree's life. The combined methods were more accurate than traditional methods when sampling schemes that involve long distances between crosscuts are carried out and especially when sampling combines variable distances between crosscuts. If a sample were available, simultaneously combining crosscuts at varying distances taken from trees having varying degrees of irregularities in stem radius and height increments, the combined methods would surpass traditional methods in accuracy. © 2013 by the Society of American Foresters.
Uribe M.E.,University of Concepción |
Uribe M.E.,Barrio Universitario |
Delaveau C.,University of Concepción |
Paredes K.,University of Concepción |
And 2 more authors.
Gayana - Botanica | Year: 2012
The in vitro germination of seeds of Vestia foetida (Ruiz et Pav.) Hoffmanns. and their multiplication was performed. A 20% in vitro germination was obtained. The best proliferation medium was MS supplemented with BAP (1.0 mg L-1) plus AIB (0.01 mg L-1), with an average of 1.7 new axillary buds per microshoot after two subcultures. © 2012, Universidad de Concepcion. All rights reserved.
Acevedo A.,Pontifical Catholic University of Valparaíso |
Acevedo A.,Barrio Universitario |
Aroca G.,Pontifical Catholic University of Valparaíso |
Aroca G.,Barrio Universitario |
And 2 more authors.
PLoS ONE | Year: 2014
Scheffersomyces stipitis is a yeast able to ferment pentoses to ethanol, unlike Saccharomyces cerevisiae, it does not present the so-called overflow phenomenon. Metabolic features characterizing the presence or not of this phenomenon have not been fully elucidated. This work proposes that genome-scale metabolic response to variations in NAD(H/+) availability characterizes fermentative behavior in both yeasts. Thus, differentiating features in S. stipitis and S. cerevisiae were determined analyzing growth sensitivity response to changes in available reducing capacity in relation to ethanol production capacity and overall metabolic flux span. Using genome-scale constraint-based metabolic models, phenotypic phase planes and shadow price analyses, an excess of available reducing capacity for growth was found in S. cerevisiae at every metabolic phenotype where growth is limited by oxygen uptake, while in S. stipitis this was observed only for a subset of those phenotypes. Moreover, by using flux variability analysis, an increased metabolic flux span was found in S. cerevisiae at growth limited by oxygen uptake, while in S. stipitis flux span was invariant. Therefore, each yeast can be characterized by a significantly different metabolic response and flux span when growth is limited by oxygen uptake, both features suggesting a higher metabolic flexibility in S. cerevisiae. By applying an optimization-based approach on the genome-scale models, three single reaction deletions were found to generate in S. stipitis the reducing capacity availability pattern found in S. cerevisiae, two of them correspond to reactions involved in the overflow phenomenon. These results show a close relationship between the growth sensitivity response given by the metabolic network and fermentative behavior. © 2014 Acevedo et al.