Introducción. La vainilla se cultiva en agreoecosistemas bajo diversa intensidad de manejo, con características ambientales particulares que podrían ser desfavorables para la orquídea. Las ...condiciones atmosféricas son importantes, debido al cambio climático. Objetivo. Caracterizar las condiciones climáticas y microclimáticas de tres sistemas productivos de vainilla (Vanilla planifolia Jacks. ex Andrews). Materiales y métodos. El estudio se realizó en tres sistemas productivos de vainilla ubicados en Veracruz y Oaxaca, México. Se utilizaron tres intensidades de manejo: a) acahual, bajo sombra de diversas especies arbóreas; b) monocultivo, intercalado con una especie arbórea y c) malla sombra (con sombra artificial). Se abarcó un año de monitoreo (diciembre-2020 a noviembre-2021), que incluyó cuatro temporadas climáticas, dos frías y dos cálidas. Se midieron variables climáticas (de la región) y microclimáticas (de la parcela): temperatura (T), humedad relativa (HR) y radiación fotosintéticamente activa (RFA, solo en el microclima), con estaciones automatizadas; además se calculó el déficit de presión de vapor (DPV). Resultados. A escala diaria, las condiciones climáticas como microclimáticas en el acahual fueron más favorables para el cultivo de vainilla en las cuatro temporadas evaluadas; el monocultivo y la malla sombra experimentaron condiciones de humedad y temperatura fuera de los requerimientos agroclimáticos de la vainilla, principalmente en marzo-mayo (MAM), con Tmax >32 °C y HR <80 %. A escala horaria, las condiciones más cálidas y secas estuvieron en el monocultivo y la malla sombra en diciembre-febrero (DEF) y MAM; mientras que en junio-agosto (JJA) y septiembre-noviembre (SON) en acahual y malla sombra; el DPV (>2 kPa) indicó periodos más prolongados de estrés hídrico en estos sistemas. Conclusiones. El monocultivo y la malla sombra presentaron condiciones de humedad y temperatura desfavorables para la vainilla, con más periodos de estrés hídrico. El acahual presentó las condiciones climáticas y microclimáticas más convenientes para el cultivo de vainilla.
Negative impacts of climate change are expected in the production of Coffea arabica L. one of the most commercialized tropical agroproducts in the world. However, most studies work with global ...circulation models, being of little use in making decisions on the scale of farm management. Given this, the objective of this study was to identify the suitability for the cultivation of C. arabica in the face of climate change and how tree cover mitigates the impacts of climate change in an agroforestry plot. The indices of climatic extremes were calculated (1961 to 2016 for Coatepec; 1985 to 2016 for Briones) and a trend analysis was carried out (Mann-Kendall). The temperature inside a plot, and on an open site, was monitored for two years (2017-2019). This was related to the climatic requirements of C. Arabica. Trends of increase (p < 0.05) of the minimum and minimum extreme annual temperatures were identified in the two stations near the plot (0.24 and 0.69 °C·decade-1 in Coatepec and 0.46 and 0.79 °C·decade-1 in Briones). The maximum temperature did not present significant increases, reducing the thermal amplitude. Both annual and seasonal precipitation shows trends of increase in intensity. All these conditions are still suitable for the cultivation of C. arabica. At the plot scale, the importance of tree cover is demonstrated, which in this agroforestry system allows to reduce the maximum temperature by 1.9 °C compared to an open site. Tree cover has also made it possible to mitigate extreme events.
This work presents an experimental study on a laboratory scale about the hydrodynamic behavior of fluid flow in a tubular reactor and a stirred tank reactor in-series and varying their arrangement. ...The experiments were carried out using stimulus-response techniques with a tracer solution of sodium chloride in unit pulse form. The experimental results allowed obtaining the Residence Time Distribution curves Rθ vs θ for different reactor arrangements. The results obtained are similar to those reported by Levenspiel for a battery in-series with a plug flow reactor and a perfectly stirred reactor. The difference found with the studied system is that these show dead water in both equipment. The arrangement of the reactors does not modify the graph of Residence Times Distribution obtained, similar to the ideal situation presented in the literature consulted. As a result of the experimental study and the adjustment of the data, a non-ideal flow model was obtained for different kinds of reactors with dead water, connected in-series and with different arrangements. The simulation of the system for different degrees of back mixing in the system reflects a behavior similar to that of series of reactors of this type, but with ideal behavior.
Abstract
Background
Non-cystic fibrosis bronchiectasis (BE) is a chronic structural lung condition that facilitates chronic colonization by different microorganisms and courses with recurrent ...respiratory infections and frequent exacerbations. One of the main pathogens involved in BE is Pseudomonas aeruginosa.
Objectives
To determine the molecular mechanisms of resistance and the molecular epidemiology of P. aeruginosa strains isolated from patients with BE.
Methods
A total of 43 strains of P. aeruginosa were isolated from the sputum of BE patients. Susceptibility to the following antimicrobials was analysed: ciprofloxacin, meropenem, imipenem, amikacin, tobramycin, aztreonam, piperacillin/tazobactam, ceftazidime, ceftazidime/avibactam, ceftolozane/tazobactam, cefepime and colistin. The resistance mechanisms present in each strain were assessed by PCR, sequencing and quantitative RT–PCR. Molecular epidemiology was determined by MLST. Phylogenetic analysis was carried out using the eBURST algorithm.
Results
High levels of resistance to ciprofloxacin (44.19%) were found. Mutations in the gyrA, gyrB, parC and parE genes were detected in ciprofloxacin-resistant P. aeruginosa strains. The number of mutated QRDR genes was related to increased MIC. Different β-lactamases were detected: blaOXA50, blaGES-2, blaIMI-2 and blaGIM-1. The aac(3)-Ia, aac(3)-Ic, aac(6″)-Ib and ant(2″)-Ia genes were associated with aminoglycoside-resistant strains. The gene expression analysis showed overproduction of the MexAB-OprM efflux system (46.5%) over the other efflux system. The most frequently detected clones were ST619, ST676, ST532 and ST109.
Conclusions
Resistance to first-line antimicrobials recommended in BE guidelines could threaten the treatment of BE and the eradication of P. aeruginosa, contributing to chronic infection.
ABSTRACT
Rationale
Cocaine addiction is a chronic relapsing disorder that lacks of an effective treatment. Isoflavones are a family of compounds present in different plants and vegetables like ...soybeans that share a common chemical structure. Previous studies have described that synthetic derivatives from the natural isoflavone daidzin can modulate cocaine addiction, by a mechanism suggested to involve aldehyde-dehydrogenase (ALDH) activities.
Objectives
Based on these previous studies, we investigated the effects of three natural isoflavones, daidzin, daidzein, and genistein, on the modulation of the cocaine reinforcing effects and on cue-induced reinstatement in an operant mouse model of cocaine self-administration.
Results
Chronic treatment with daidzein or genistein decreased operant responding to obtain cocaine intravenous infusions. On the other hand, daidzein and daidzin, but not genistein, were effective in decreasing cue-induced cocaine reinstatement. Complementary studies revealed that daidzein effects on cocaine reinforcement were mediated through a mechanism that involved dopamine type-2/3 receptors (DA-D2/3) activities.
Conclusions
Our results suggest that these natural compounds alone or in combination can be a potential therapeutic approach for cocaine addiction. Further clinical studies are required in order to ascertain their potential therapeutic use.
Resumen Se prevén impactos negativos del cambio climático en la producción de Coffea arabica L. uno de los agroproductos tropicales más comercializados en el mundo. Sin embargo, la mayoría de los ...estudios trabajan con modelos de circulación global, siendo poco útiles en la toma de decisiones a escala de manejo de una finca. Ante ello, el objetivo de este estudio fue identificar la aptitud para el cultivo de C. arabica ante el cambio climático y cómo la cobertura arbórea mitiga los impactos del cambio climático en una parcela agroforestal. Se calcularon los índices de extremos climáticos (1961 a 2016 para Coatepec; 1985 a 2016 para Briones) y se realizó un análisis de tendencias (Mann-Kendall). Se monitoreó la temperatura en el interior de una parcela, y en un sitio abierto, durante dos años (2017-2019). Esto se relacionó con los requerimientos climáticos de C. arabica. Se identificaron tendencias de incremento (p<0,05) de las temperaturas mínima y mínima extrema anual en las dos estaciones cercanas a la parcela (0,24 y 0,69 °C·década-1 en Coatepec y 0,46 y 0,79 °C·década-1 en Briones). La temperatura máxima no presentó incrementos significativos, reduciendo la amplitud térmica. Tanto la precipitación anual y estacional muestran tendencias de incremento en intensidad. Todas estas condiciones siguen siendo aptas para el cultivo de C. arabica. A escala de parcela, se demuestra la importancia de la cobertura arbórea, que en este sistema agroforestal permite reducir la temperatura máxima 1,9 °C en comparación con un sitio abierto. Asimismo, la cobertura arbórea ha permitido mitigar eventos extremos.
Objectives: To evaluate the expression dynamics of biofilm genes in methicillin-resistant Staphylococcus aureus (MRSA) retrieved from endotracheal tubes (ETT) and to determine how gene regulation is ...attenuated in vitro where host–environmental factors are no longer present. Methods: Biofilm was grown (24 h) in tryptic broth soy plus 0.25% glucose for a clinical MRSA isolate in planktonic state and after sessile growth named ETT-MRSA (S2, S3, S4, S5, S6, S7). Gene expression of five biofilm-related genes (icaC, clfB, ebps, fnbB, and RNA III) was assessed consecutively from day 1 to day 4 after ETT growth through real-time PCR. 16S rRNA was used as a control. Results: The MRSA isolates retrieved from ETT were capable of producing biofilms dependent on ica. The gene expression dynamics of ETT-MRSA changed progressively compared to planktonic MRSA gene expression under both ambient air (p < 0.001) and ambient air with 5% CO2 (p < 0.001). Dynamic assessment of icaC expression in both atmospheric conditions showed progressive downregulation in vitro compared to in vivo ETT biofilms. The expression patterns of clfB and ebps genes were similar to icaC. In contrast, the expression of the RNA III gene showed progressive upregulation from day 1 to day 4 (p < 0.001). Conclusions: MRSA loses its biofilm gene expression in vitro, by adaptive features across multiple generations, as evidenced by the progressive downregulation of icaC and upregulation of RNA III. These findings underscore the significance of host–environment dependence in regulating bacterial biofilm genes, highlighting its importance in diagnostics. Bacterial strains lose their host-specific characteristics as they are cultured in vitro.
Ethylene production was measured from excised 10‐mm apical and subapical root segments from 50 cultivars in 19 species of 7 families. Monocotyledonous species tended to have much lower rates of ...ethylene production than dicotyledonous species. Ethylene production was generally higher in apical root segments than in subapical segments within 1 h of wounding. However, cultivars of Cucumis melo, C. sativus, Helianthus annuus, Hibiscus esculentus, and Zea mays had higher rates of ethylene production from subapical segments. In apical root segments, Phaseolus aureus cv. Berken had the highest ethylene production rate (76.7 ηl g−1 h−1), while Zea mays cv. Silver Queen had the lowest rate (0.6 ηl g−1 h−1). In subapical root segments, Cucumis sativus cv. Armenian had the highest rate (55.7 ηl g−1 h−1), while Zea mays cv. Silver Queen again had the lowest rate (0.6 ηl g−1 h−1). The many different responses in magnitude and kinetics of wound‐induced ethylene production among the species, cultivars and tissues should provide interesting and useful systems with which to study wound responses and induced ethylene production.
El trabajo tuvo como objetivo determinar el diámetro de colonia con su halo celulolítico de las bacterias termófilas GCB-13 y GCC-13 a diferentes temperaturas. Las bacterias fueron reactivadas en ...caldo CMC e incubadas a 50 °C por 48h, luego sembradas por puntura en el medio agar CMC contenido en placas Petri por triplicado para cada temperatura a la que fue incubado (35, 40, 45, 50, 55 y 60 °C) durante 48 horas. El diámetro de las colonias con sus halos celulolíticos se obtuvo con ayuda de una regla milimetrada. El halo de hidrólisis fue obtenido restando el diámetro de la colonia del diámetro de la colonia con halo celulolítico. Los diámetros máximos (mm) obtenidos de colonia y de halo celulolítico, respectivamente, fueron para la bacteria GCB-13 9,17 a 45°C y 6,42 a 55°C, y para la bacteria GCC-13 10,33 a 45 °C y 7,33 a 50 °C.
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