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Item Obesogenic Diet-Induced Neuroinflammation: A Pathological Link between Hedonic and Homeostatic Control of Food Intake(2023-01-11) Marcos, José Luis; Olivares-Barraza, Rossy; Ceballo, Karina; Wastavino, Melisa; Ortiz, Víctor; Riquelme, Julio; Martínez-Pinto, Jonathan; Muñoz, Pablo; Cruz, Gonzalo; Sotomayor-Zárate, RamónObesity-induced neuroinflammation is a chronic aseptic central nervous system inflammation that presents systemic characteristics associated with increased pro-inflammatory cytokines such as interleukin 1 beta (IL-1β) and interleukin 18 (IL-18) and the presence of microglia and reactive astrogliosis as well as the activation of the NLRP3 inflammasome. The obesity pandemic is associated with lifestyle changes, including an excessive intake of obesogenic foods and decreased physical activity. Brain areas such as the lateral hypothalamus (LH), lateral septum (LS), ventral tegmental area (VTA), and nucleus accumbens (NAcc) have been implicated in the homeostatic and hedonic control of feeding in experimental models of diet-induced obesity. In this context, a chronic lipid intake triggers neuroinflammation in several brain regions such as the hypothalamus, hippocampus, and amygdala. This review aims to present the background defining the significant impact of neuroinflammation and how this, when induced by an obesogenic diet, can affect feeding control, triggering metabolic and neurological alterations.Item Rosuvastatin Synergistically Enhances the Antinociceptive Efficacy of Duloxetine in Paclitaxel-Induced Neuropathic Pain in Mice(2023-05-06) Lobos, Nicolás; Lux, Sebastián; Zepeda, Ramiro Javier; Pelissier, Teresa; Marcos, José Luis; Bustos-Quevedo, Gonzalo; Hernández, Alejandro; Constandil, LuisPaclitaxel, a widely used cancer chemotherapeutic agent, has high incidence of neurotoxicity associated with the production of neuropathic pain, for which only duloxetine has shown significant but moderate analgesic effect. Since statins, classically used to reduce hypercholesterolemia, have shown antinociceptive effect in preclinical studies on neuropathic pain, we studied whether the antinociceptive efficacy of duloxetine could be synergistically potentiated by rosuvastatin in a model of paclitaxel-induced neuropathy in mice. The astrocytic and microglial responses in the spinal cord of paclitaxel-treated mice were also assessed by measuring GFAP and CD11b proteins, respectively. Paclitaxel treatment did not impair motor coordination and balance in rotarod testing. Rosuvastatin, duloxetine, and the rosuvastatin/duloxetine combination (combined at equieffective doses) dose-dependently decreased mechanical allodynia (ED30, von Frey testing) and thermal hyperalgesia (ED50, hot plate testing) in paclitaxel-treated mice. Isobolographic analysis showed a superadditive interaction for rosuvastatin and duloxetine, as both the ED30 and ED50 for the rosuvastatin/duloxetine combination contained only a quarter of each drug compared to the individual drugs. The rosuvastatin/duloxetine combination reversed paclitaxel-induced GFAP overexpression, indicating that such effects might depend in part on astrocyte inactivation. Results suggest that statins could be useful in synergistically enhancing the efficacy of duloxetine in some chemotherapy-induced neuropathic conditions.Item Changes in Dynamic Thiol/Disulfide Homeostasis, and Substance P, B-Endorphin and α-Tocopherol Concentrations in the Spinal Cord of Chronically Lame Dairy Cows(2023-05-12) Müller, Heine; Herzberg, Daniel; Chihuailaf, Ricardo; Strobel, Pablo; Werner, Marianne; Bustamante, HedieInitial lameness inflammation leads to chronic lameness and development of chronic pain due to the release of pro-inflammatory mediators such as reactive oxygen species (ROS), which are implicated in the transition from acute to chronic pain, and free radical scavengers countering thiol, substance P (SP), and β-endorphin (BE). The present study aimed to evaluate the dynamic thiol–disulfide homeostasis, α-tocopherol concentrations and SP and BE concentrations in the spinal cord of chronically lame dairy cows. Ten lame and 10 non-lame cows with a parity range of 2–6 were selected for the study. Lame cows had a history of up to 3 months of lameness. Spinal cord samples were obtained from the L2 to L4 lumbar vertebrae aspect of each animal. A thiol–disulfide homeostasis assay was performed using absorbance, and the α-tocopherol concentration was determined by HPLC. SP and BE concentrations were measured using ELISA kits. The results indicated that SP and BE were significantly higher in the spinal cord of lame cows. In contrast, disulfide levels and α-tocopherol concentrations were significantly lower in the spinal cord of lame cows. In conclusion, disulfide levels and α-tocopherol concentrations indicated a defective antioxidant response in cows with chronic lameness. The results of SP and BE concentrations suggested chronic pain and a defective endogenous analgesic response.Item Protocol for in vitro rooting of Pyrus comunnis rootstocks(2023-04-15) Nadal, Michele Carla; Bernardes Machado, Otávio; Araújo, Ronilson Carlos; Rodrigues, Filipe Almendagna; Rufato, Leo; Dória, Joyce; Pasqual, MoacirEffective protocols for in vitro rooting for woody fruit trees are still a challenge for in vitro seedling production, especially when there is a need to insert new cultivars or rootstocks. These protocols are essential to accelerate studies in plant breeding programs and for seedling distribution. This study evaluated the use of 6-Benzylaminopurine (IBA) in in vitro rooting of Pyruscomunnis rootstocks, clones ‘OHxF87’ and Pyrodwarf. Explant exposure times (0, 24, 48, 72, and 96 hours) to 20 mg L-1 IBA were tested for in vitro rooting. The exposure to IBA resulted in rooting rates above 80%, surpassing some results reported in the literature. The 24-hour treatment provided 81,81% survival, leading to an average growth of five roots with 19 mm length, for ‘OHxF87’ rootstock. The same exposure time resulted in the highest survival rate (75%) and the highest mean root number, seven roots per plant with 10 mm length, for ‘PDW’ rootstock. Root formation did not occur in the absence of synthetic auxin. Therefore, it can be concluded that a 24-hour exposure at 20 mg L-1 IBA was sufficient to promote in vitro rooting in ‘OHxF87’ and Pyrodwarf rootstocks’.Item Dendrobium nobile in vitro flowering induction(2023-05-22) Nadal, Michele Carla; Silva Andrade, Gracielle Vidal; Nunes Flores, José Henrique; dos Reis, Michele Valquíria; Rodrigues, Vantuil Antonio; Pasqual, MoacirIn vitro flowering is a technique used in genetic improvement that accelerates generations and favors the faster fixation of new traits of agronomic and market interest. The study aimed to establish a protocol for the in vitro flowering of Dendrobium nobile, through the combined temperature and of the growth regulator thidiazuron (TDZ) effects. Experiments was performed in a flask that was kept in a BOD incubator at 18, 21, or 24 °C or in a growth room at 26 °C. The TDZ concentrations were 0.0, 0.5, 1.0, and 2.0 mg L-1. The highest percentage of flowering shoots of 13.7% occurred at a concentration of 2 mg L-1 of TDZ grown at a temperature of 18 °C. Dendrobium nobile in vitro flowering was promoted in plants cultivated in ½ MS supplemented with 30 g L-1 sucrose, 5.5 g L-1 agar, 100 mL L-1 coconut water, pH 6.0, and 2.0 mg L-1 TDZ at a controlled temperature of 18 °C and a photoperiod of 16 h. The in vitro flowering induction protocol of the D. nobile species could be used or improved for future studies.Keywords: flowering, temperature, thidiazuron, Orchidaceae.Item Humans as blood-feeding sources in sylvatic triatomines of Chile unveiled by next-generation sequencing(2023-07-06) San Juan, Esteban; Araya‑Donoso, Raúl; Sierra‑Rosales, Catalina; Correa, Juana P; Quiroga, Nicol; Campos‑Soto, Ricardo; Solari, Aldo; Llewellyn, Martin; Bacigalupo, Antonella; Botto‑Mahan, CarezzaBackground Triatomines are blood-sucking insects capable of transmitting Trypanosoma cruzi, the parasite that causes Chagas disease in humans. Vectorial transmission entails an infected triatomine feeding on a vertebrate host, release of triatomine infective dejections, and host infection by the entry of parasites through mucous membranes, skin abrasions, or the biting site; therefore, transmission to humans is related to the triatomine–human contact. In this cross-sectional study, we evaluated whether humans were detected in the diet of three sylvatic triatomine species (Mepraia parapatrica, Mepraia spinolai, and Triatoma infestans) present in the semiarid–Mediterranean ecosystem of Chile. Methods We used triatomines collected from 32 sites across 1100 km, with an overall T. cruzi infection frequency of 47.1% (N=4287 total specimens) by conventional PCR or qPCR. First, we amplifed the vertebrate cytochrome b gene (cytb) from all DNA samples obtained from triatomine intestinal contents. Then, we sequenced cytb-positive PCR products in pools of 10–20 triatomines each, grouped by site. The fltered sequences were grouped into amplicon sequence variants (ASVs) with a minimum abundance of 100 reads. ASVs were identifed by selecting the best BLASTn match against the NCBI nucleotide database. Results Overall, 16 mammal (including human), 14 bird, and seven reptile species were identifed in the diet of syl‑ vatic triatomines. Humans were part of the diet of all analyzed triatomine species, and it was detected in 19 sites representing 12.19% of the sequences. Conclusions Sylvatic triatomine species from Chile feed on a variety of vertebrate species; many of them are detected here for the frst time in their diet. Our results highlight that the sylvatic triatomine–human contact is noteworthy. Education must be enforced for local inhabitants, workers, and tourists arriving in endemic areas to avoid or minimize the risk of exposure to Chagas disease vectors.Item The use of filamentous hemagglutinin adhesin to detect immune responses to Campylobacter hepaticus infections in layer hens(2022-12-21) Muralidharan, Chithralekha; Quinteros, José A.; Anwar, Arif; Wilson, Timothy B.; Scott, Peter C.; Moore, Robert J.; Hao Van, Thi ThuCampylobacter hepaticus is the aetiological agent of Spotty Liver Disease (SLD). SLD can cause significant production loss and mortalities among layer hens at and around peak of lay. We previously developed an enzyme linked immunosorbent assay (ELISA), SLD-ELISA1, to detect C. hepaticus specific antibodies from bird sera using C. hepaticus total proteins and sera pre-absorbed with Campylobacter jejuni proteins. The high specificity achieved with SLD-ELISA1 indicated the presence of C. hepaticus specific antibodies in sera of infected birds. However, some of the reagents used in SLD-ELISA1 are time consuming to prepare and difficult to quality control. This understanding led to the search for C. hepaticus specific immunogenic proteins that could be used in recombinant forms as antibody capture antigens in immunoassay design. In this study, an immunoproteomic approach that combined bioinformatics analysis, western blotting, and LC MS/MS protein profiling was used, and a fragment of filamentous hemagglutinin adhesin (FHA), FHA1,628−1,899 with C. hepaticus specific antigenicity was identified. Recombinant FHA1,628−1,899 was used as antigen coating on ELISA plates to capture FHA1,628−1,899 specific antibodies in sera of infected birds. SLD-ELISA2, based on the purified recombinant FHA fragment, is more user-friendly and standardizable than SLD-ELISA1 for screening antibody responses to C. hepaticus exposure in hens. This study is the first report of the use of FHA from a Campylobacter species in immunoassays, and it also opens future research directions to investigate the role of FHA in C. hepaticus pathogenesis and its effectiveness as a vaccine candidate.Item Obesogenic Diet-Induced Neuroinflammation: A Pathological Link between Hedonic and Homeostatic Control of Food Intake(2023-01-11) Marcos, José Luis; Olivares-Barraza, Rossy; Ceballo, Karina; Wastavino, Melisa; Ortiz, Víctor; Riquelme, Julio; Martínez-Pinto, Jonathan; Muñoz, Pablo; Cruz, Gonzalo; Sotomayor-Zárate, RamónObesity-induced neuroinflammation is a chronic aseptic central nervous system inflammation that presents systemic characteristics associated with increased pro-inflammatory cytokines such as interleukin 1 beta (IL-1β) and interleukin 18 (IL-18) and the presence of microglia and reactive astrogliosis as well as the activation of the NLRP3 inflammasome. The obesity pandemic is associated with lifestyle changes, including an excessive intake of obesogenic foods and decreased physical activity. Brain areas such as the lateral hypothalamus (LH), lateral septum (LS), ventral tegmental area (VTA), and nucleus accumbens (NAcc) have been implicated in the homeostatic and hedonic control of feeding in experimental models of diet-induced obesity. In this context, a chronic lipid intake triggers neuroinflammation in several brain regions such as the hypothalamus, hippocampus, and amygdala. This review aims to present the background defining the significant impact of neuroinflammation and how this, when induced by an obesogenic diet, can affect feeding control, triggering metabolic and neurological alterations.Item Quantifying effects of irrigation and soil water content on electricalpotentials in grapevines (Vitis vinifera) using multivariate statisticalmethods(2014-05-20) Gil, Pilar M.; Saavedra, Jorge; Schaffer, Bruce; Navarro, Rosa; Fuentealba, ClaudiaSeveral studies have shown that physiological responses in plants, including fruit crops, are associated with changes in electrical potentials (EP), but it is often difficult to statistically quantify these responses. This study tested the effects of irrigation on EP in grapevines (Vitis vinifera), taking into account vapor pressure deficit (VPD) and position of electrodes along the stem by using multivariate analytical methods and a suite of statistical pretreatments. In two separate experiments, plants were exposed to one of two irrigation treatments in a greenhouse: (T1) irrigation once per day (Experiment 1), or no irrigation (Experiment 2); or (T2) irrigation three times or twice per day (Experiments 1 and 2, respectively). In each experiment, EP at three positions along the stem, soil (potting medium) water content, and VPD were continuously measured. In Experiment 2, stomatal conductance (gs) and stem water potential (SWP) were also measured for plants in each irrigation treatment as indicators of plant water status. Data were analyzed by Principal Component Analysis (PCA) to determine the effects of irrigation treatment on EP and difference in EP between pairs of electrodes (ΔEP) at various locations along the stem. Data were also analyzed by partial least squares (PLS) analysis to determine if EP or ΔEP could be used as predictors of changes in soil water content due to different irrigation treatments. Significant differences in soil water content due to irrigation treatments could be readily detected by difference in EP or ΔEP using PCA with Orthogonal Signal Correction pre-processing. Also, PLS showed that differences in soil moisture can be predicted by EP and/or ΔEP measurements at specific locations along the stem. Thus, the use of multivariate statistical methods was effective for relating EP and ΔEP measurements in grapevines to soil moisture due to differences in irrigation.Item Simazine transport in undisturbed soils from a vineyard at the Casablanca valley, Chile(2013-01-20) Suárez, Francisco; Guzmán, Edwin; Muñoz, José F.; Bachmann, Jaime; Ortiz, Cristian; Alister, Claudio; Kogan, MarceloSimazine is a soil-active herbicide that has been applied worldwide in agricultural soils, being the second most commonly detected herbicide in groundwater and surface waters. Although its use has been restricted in many countries of Europe, it is still applied in many locations around the world in orchards, vineyards and forestry. Therefore, it is important to study its fate and transport in the environment. This paper investigates simazine transport in undisturbed bare soils from a vineyard at the Casablanca valley, Chile. In the study site, shallow groundwater tables (<1.0 m depth) and high simazine levels (>15 μg L−1) in the groundwater were observed and thus, there is potential for simazine to be transported further away through the saturated zone. The soils from the study site were characterized and the hydrodynamic transport parameters were determined. Column leaching experiments showed that the two-site chemical non-equilibrium model correctly represented simazine transport. It was found that 36.3% of the adsorption sites achieve instantaneous equilibrium and that the first-order kinetic rate of the non-equilibrium sites was 6.2 × 10−3 h−1. Hydrus 2D was used to predict the transport of simazine in the study site under natural field conditions. Simulation results showed that simazine concentrations at depths shallower than 2.1 m are above the maximum contaminant level of 4 μg L−1 (defined by the U.S. Environmental Protection Agency). The timing of herbicide application was found to be important on simazine leaching and the main processes involved in simazine transport were degradation and adsorption, which accounted for 95.78 and 4.19% of the simulated mass of pesticide, respectively. A qualitative agreement in the timing and magnitude of simazine concentration was obtained between the simulations and the field data. Therefore, the model utilized in this investigation can be used to predict simazine transport and is a valuable tool to assess agricultural practices to minimize environmental impacts of simazine.Item Competitive Strategies and Growth of Neighbouring Bromus valdivianus Phil. and Lolium perenne L. Plants Under Water Restriction(2013-05) López, F.; Kemp, P. D.; Dörner, J.; Descalzi, C. A.; Balocchi, O. A.; García, S.Often perennial pastures have to tolerate soil water restriction during summer, which can affect the relative abundance of the most desired species. In the south of Chile, Bromus valdivianus and Lolium perenne are preferred species. The competitiveness of B. valdivianus and L. perenne was evaluated when sown in pots in a glasshouse as monocultures or a mix (50/50 %) with restricted water availability. The water restriction treatments were as follows: 80–85 % field capacity (FC), 45–50 % FC and 20–25 % FC, maintained for 1196 growing degree days. For both species, dry matter (DM) accumulated per plant and per pot decreased similarly with increasing water restriction, but at tiller level, resource allocation differed, for B. valdivianus root growth was accentuated over aerial development, but this was less so for L. perenne. The foliage mass per tiller for B. valdivianus decreased relatively more than that for L. perenne with increasing water restriction. As monocultures, B. valdivianus produced larger tillers than L. perenne, such that B. valdivianus tillers had 2.2 times greater lamina mass, 3.6 times more leaf area and 2.5 times greater root mass than those of L. perenne. However, L. perenne produced a larger number of smaller tillers that enabled foliage, root and total mass at plant level, to be similar to that of B. valdivianus. Within the mixed pasture, L. perenne tiller density increased compared with when grown as a monoculture, but not for B. valdivianus. The results of the study suggested that L. perenne and B. valdivianus have differences in growth strategies that allow them to survive under environmental stress and competition. Competitiveness increased for L. perenne aboveground without water restriction and that for B. valdivianus increased belowground as water restriction was increased.Item Water and sediment dynamics of penoxsulam and molinate in paddy fields: field and lysimeter studies(2011-07-15) Kogan, Marcelo; Araya, Manuel; Alister, ClaudioBACKGROUND: In Chile, rice is cultivated under water-seeded and continuously flooded conditions. Because herbicide dynamics in paddy fields and non-flooded fields is different, 3 year experiments were performed to study the dissipation of molinate and penoxsulam in water and sediment. RESULTS: In field experiments, both herbicides dissipated by 45–55% from the initial applied amounts during the first 6 h after application in all crop seasons; in lysimeter experiments, dissipation amounts were approximately 10% for penoxsulam and 16% for molinate. Penoxsulam field water DT50 values varied from 1.28 to 1.96 days during the three study seasons, and DT90 values from 4.07 to 6.22 days. Molinate field water DT50 values varied from 0.89 to 1.73 days, and DT90 values from 2.82 to 5.48 days. Sediment residues were determined 2 days after herbicide application into the paddy water, and maximum concentrations were found 4–8 days after application. In sediment, DT50 values varied from 20.20 to 27.66 days for penoxsulam and from 15.02 to 29.83 days for molinate. CONCLUSIONS: Results showed that penoxsulam and molinate losses under paddy conditions are dissipated rapidly from the water and then dissipate slowly from the sediment. Penoxsulam and molinate field water dissipation was facilitated by paddy water motion created by the wind. SedimentItem Glyphosate Use in Forest Plantations(2010) Kogan, Marcelo; Alister, ClaudioUnder Chilean conditions the lack of weed control at forest tree establishment results in an average of at least 60% less biomass accumulation during the first year of growth of radiate pine or eucaliptus, and glyphosate offers a series of advantages in forestry weed management because its activity in both herbaceous weed groups, monocots and dicots, as well as annuals, biennials and perennials. Also, its efficacy in woody undesirable vegetation makes glyphosate a very important herbicide that can be applied to control herbaceous and woody weeds as pre-planting and during the second or third years of trees growth as strip applications. The aim of this review is to discuss the main uses of glyphosate in reforestation worldwide, during the first 2 yr after tree establishment, as broadcast application over the top of the forest trees and the most important factors that could affect glyphosate efficacy as a forest herbicide, like weed growth stage, application technique, volume and water quality, rainfastness, dew effect and the use of extra adjuvant with formulated glyphosate.Item Adsorption and desorption variability of four herbicides used in paddy rice production(2011-01) Alister, Claudio A.; Araya, Manuel A.; Kogan, MarceloThis investigation was performed to determine the effect of physicochemical soil properties on penoxsulam, molinate, bentazon, and MCPA adsorption-desorption processes. Four soils from Melozal (35° 43' S; 71° 41' W), Parral (36° 08' S; 71° 52' W), San Carlos (36° 24' S; 71° 57' W), and Panimavida (35° 44' S; 71° 24' W) were utilized. Herbicide adsorption reached equilibrium after 4 h in all soils. The Freundlich L-type isotherm described the adsorption process, which showed a high affinity between herbicides and sorption sites mainly because of hydrophobic and H-bonds interaction. Penoxsulam showed the highest adsorption coefficients (4.23 ± 0.72 to 10.69 ± 1.58 mL g⁻¹) and were related to soil pH. Molinate showed K(d) values between 1.72 ± 0.01 and 2.3 ± 0.01 mL g⁻¹ and were related to soil pH and organic matter, specifically to the amount of humic substances. Bentazon had a high relationship with pH and humic substances and its K(d) values were the lowest, ranging from 0.11 ± 0.01 to 0.42 ± 0.01 mL g⁻¹. MCPA K(d) ranged from 0.14 ± 0.02 to 2.72 ± 0.01 mL g⁻¹, however its adsorption was related to humic acids and clay content. According to these results, the soil factors that could explain the sorption process of the studied herbicides under paddy rice soil conditions, were principally humic substances and soil pH. Considering the sorption variability observed in this study and the potential risk for groundwater contamination, it is necessary to develop weed rice management strategies that limit use of herbicides that exhibit low soil adsorption in areas with predisposing conditions to soil leaching.Item Using penoxsulam ALS inhibitor as a broad-spectrum herbicide in Chilean rice(2011) Kogan, Marcelo; Gómez, Patricio; Fischer, Albert; Alister, ClaudioThe continuously-flooded rice production system in Chile has selected highly competitive aquatic weeds selection capable ofreducing paddy yields by 25 to 50%. Penoxsulam is a broad-spectrum triazolopyrimidine (ALS inhibitor) commercially introduced in Chile in 2006, where Alisma plantago aquatica hads already evolved resistance to sulfonylurea herbicides (SU). Several field trials with water seeded rice were conducted during 2003 and 2004 in Chile to determine efficacy, timing of application, spectrum of control, and control of SU-resistant A. plantago aquatica with the herbicide penoxsulam, either in single applications or in sequence with other herbicides. Penoxsulam was applied a) 12 days after seeding (DAS) into the water (IW), b) in postemergence after draining the water from field (ADW) at 35 DAS or c) IW followed by ADW applications of MCPA, cyhalofop, bentazon, or triclopyr. Penoxsulam was tested at 20, 30, and 40 g a.i. ha-1. Comparisons were made with recommended rates of other IW treatments (metsulfuron, bensulfuron and cyclosulfomuron) and sequential applications of molinate (IW) followed by ADW applications of MCPA, cyhalofop, bentazon, or triclopyr. One IW penoxsulam application was sufficient to achieve broad-spectrum control: Echinochloa spp. (100% control), A.plantago-aquatica (80 to 100%), Schoenoplectus mucronatus (50 to 80%), and Cyperus difformis (80 to 100%). Rice yields in penoxsulam-treated plots were 30 to 56% higher than in the untreated controls. Yields with penoxsulam IW (all rates) were similar (P>0.05) to those obtained using molinate (IW) followed by ADW applications of bentazon or MCPA. Although penoxsulam is an ALS inhibitor, it controlled A. plantago-aquatica resistant to metsulfuron and bensulfuron.Item Effects of physicochemical soil properties of five agricultural soils on herbicide soil adsorption and leaching(2011) Alister, Claudio; Araya, Manuel; Kogan, MarceloOnce pesticides reach the soil, there are several factors that affect their soil behavior. To identify the principal soil and herbicide properties that control their adsorption and leaching, a study of five Chilean agricultural and forest soils was performed. Simazine, diuron, terbuthylazine and MCPA were applied to the top of 45-cm tall by 12-cm diameter disturbed soil columns, filled with either an Andisol, Ultisol, Entisol or one of two Inceptisol soils. After herbicide applications, each lysimeter received 24 mm of simulated rain every 24 hours for five days. Once water percolation stopped, the lysimeters were divided into five sections and herbicide concentrations were quantified using High Pressure Liquid Chromatography. Relationships between soil physicochemical properties, herbicide sorption (adsorption and desorption) and herbicide leaching were determined. All herbicides exhibited the least depth reached from the Andisol soil (10 cm) and the highest from the Ultisol soil (45 cm). The principal soil property that affected herbicide adsorption was the soil organic carbon content, specifically the fulvic acid-humins fraction. Soil leaching was related to the inverse of soil adsorption (1/Kd), cation exchange capacity, humic substances content and herbicide pKa. These results suggest that it is possible to develop simple quantitative models to predict the soil-leaching properties of pesticides.Item Efectos de Aceites Esenciales de Lavanda y Eucalipto en el Control de la Varroasis de Apis melifera(2018) Marcos, J.; Ahumada, M.; Cadavid, A.; Bañares, G.; Silva, C.Las abejas como polinizadores participan en la economía global y su aporte ha sido estimado entre 235 y 285 billones de US$ al año. (Lautenbach, et al., 2012) Actualmente se ha informado el debilitamiento general de las abejas melíferas, representado por pérdidas de colonias, elevando la preocupación pública, encareciendo el manejo de las colonias de abejas y aumentando los costos de los servicios de polinización (Calderone, 2012). El ácaro Varroa destructor se considera un impulsor crucial de esta difícil situación mundial de colonias de de abejas (Le Conte, et al., 2010). Los métodos actuales utilizados para controlarlo, son la aplicación de acaricidas piretroides (fluvalinate) y organofosforados (coumaphos) que inicialmente fueron altamente efectivos, pero el uso frecuente de estos ha llevado al desarrollo de la resistencia de los ácaros (Milani, 1999). Los aceites esenciales (AE) ofrecen una alternativa generalmente más barata y segura para el hombre y las abejas (Isman 2000). Son clasificados como suplementos alimenticios y seguros para consumo humano (Quarles, 1996). Los AE, pueden alterar el comportamiento, el crecimiento y desarrollo, la ecdisis, el apareamiento y la oviposición de los insectos (Khater, 2011). La actividad insecticida de los componentes de los AE de lavanda y eucalipto ha sido relacionada con la inhibición de la acetilcolinesterasa y como agonista octopaminergico respectivamente. (Rattan, 2010). El AE de eucaliptus es efectivo en reducir la población de varroa, (Principal, et al., 2004) El objetivo fue determinar el efecto de los AE de lavanda y eucalipto para el control de la varroasis en condiciones de campo.Item Corticotropin-releasing factor system in the lateral septum: Implications in the pathophysiology of obesity(2022-09-20) Olivares-Barraza, Rossy; Marcos, José Luis; Martínez-Pinto, Jonathan; Fuenzalida, Marco; Bravo, Javier A.; Gysling, Katia; Sotomayor-Zárate, RamónObesity is a pandemic associated with lifestyles changes. These include excess intake of obesogenic foods and decreased physical activity. Brain areas, like the lateral hypothalamus (LH), ventral tegmental area (VTA), and nucleus accumbens (NAcc) have been linked in both homeostatic and hedonic control of feeding in experimental models of diet-induced obesity. Interestingly, these control systems are regulated by the lateral septum (LS), a relay of γ-aminobutyric (GABA) acid neurons (GABAergic neurons) that inhibit the LH and GABAergic interneurons of the VTA. Furthermore, the LS has a diverse receptor population for neurotransmitters and neuropeptides such as dopamine, glutamate, GABA and corticotropin-releasing factor (CRF), among others. Particularly, CRF a key player in the stress response, has been related to the development of overweight and obesity. Moreover, evidence shows that LS neurons neurophysiologically regulate reward and stress, although there is little evidence of LS taking part in homeostatic and hedonic feeding. In this review, we discuss the evidence that supports the role of LS and CRF on feeding, and how alterations in this system contribute to weight gain obesity.Item Daily changes on seasonal ecophysiological responses of the intertidal brown macroalga Lessonia spicata: Implications of climate change(2022-09-28) Celis-Pla, Paula S. M.; Trabal, Andres; Navarrete, Camilo; Troncoso, Macarena; Moenne, Fabiola; Zuñiga, Antonio; Figueroa, Felix L.; Saéz, Claudio A.Global climate change is expected to have detrimental effects on coastal ecosystems, with impacts observable at the local and regional levels, depending on factors such as light, temperature, and nutrients. Shifts in dominance between primary producers that can capitalize on carbon availability for photosynthesis will have knock-on effects on marine ecosystems, affecting their ecophysiological responses and biological processes. Here, we study the ecophysiological vulnerability, photoacclimation capacity, and tolerance responses as ecophysiological responses of the intertidal kelp Lessonia spicata (Phaeophyceae, Laminariales) during a year through different seasons (autumn, winter, spring, and summer) in the Pacific Ocean (central Chile). Six different daily cycle experiments were carried out within each season. A battery of different biochemical assays associated with antioxidant responses and in-vivo chlorophyll a fluorescence parameter showed that during spring and summer, there was an increase in photosynthetic capacity in the macroalgae, although their responses varied depending on light and nutrient availability in the course of the year. Lessonia spicata showed maximal photosynthesis and a similar photoinhibition pattern in summer compared to the other seasons, and the contents of nitrate and phosphorous in seawater were less in winter. Thus, high irradiance during spring and summer displayed a higher maximal electron transport rate (ETRmax), irradiance of saturation (Ek), non-photochemical quenching (NPQmax), nitrogen and carbon contents, and photoprotector compound levels. Antioxidant activity increased also in summer, the seasonal period with the highest oxidative stress conditions, i.e., the highest level of hydrogen peroxide (H2O2). In contrast, under low irradiance, i.e., wintertime conditions, L. spicata demonstrated lower concentrations of the photosynthetic pigments such as chlorophyll a and carotenoids. Our study suggests that macroalgae that are subjected to increased irradiance and water temperature under lower nutrient availability mediated by seasonal changes (expected to worsen under climate change) respond with higher values of productivity, pigment contents, and photoprotective compounds. Thus, our findings strengthen the available evidence to predict that algae in the order Laminariales, specifically L. spicata (kelp), could better proliferate, with lower vulnerability and greater acclimation, than other marine species subject to future expected conditions associated with climate change.Item Evaluación de hongos micorrízicos arbusculares (HMA) en la rehabilitación ecológica de ecosistemas con actividad minera(2022) Arancibia, Rosa; Flores, Manuel; Cabrera, Tatiana; Sanchez Beiza, Juan; Obando, JavierEn los ecosistemas forestales nativos, los hongos micorrízicos arbusculares (HMA) cumplen una función de interfase suelo – planta, ayudando a la adaptación de las especies vegetales ante situaciones de estrés. En Chile existe escasa información en el bosque esclerófilo de la zona central, por lo que se propuso identificar y cuantificar las esporas de HMA en suelo rizosférico para las especies Beilschmiedia miersii, Peumus boldus, Citronella mucronata y de un sitio sujeto a rehabilitación ecológica debido a la acción minera, denominado “El Gallo”, presentes en la cordillera de la costa de la región de Valparaíso. Se colectó muestras de la rizósfera de las tres especies y del sitio en rehabilitación y se sometieron a análisis morfométrico; tamizado a 63, 149 y 297 µm y filtrado, con conteo de esporas en 50 g de suelo rizosférico en invierno (agosto de 2019) y verano (enero de 2020). Se identificó los géneros Glomus sp. y Acaulospora sp. y se determinó que la densidad de esporas HMA/ 50 g de suelo en el sitio El Gallo en tamizado a 149 y 297 µm fue menor con respecto de la densidad que presentaron las muestras de suelo rizosférico de las tres especies esclerófilas. Estos resultados establecen un valor de referencia respecto a la densidad de esporas presentes para la gestión de mejoras en la cantidad y diversidad de HMA en un manejo de sucesión de especies del bosque nativo esclerófilo.
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