Modified cyclodextrin type and dehydration methods exert a significant effect on the antimicrobial activity of encapsulated carvacrol and thymol

BACKGROUND The antimicrobial activity of essential oils and their constituents has led to increasing interest in using them as natural preservative agents. However, their high sensitivity to light and oxygen, their volatility and their low aqueous solubility are all obstacles to their application in the food, cosmetic or pharmaceutical industries. Encapsulation in cyclodextrins (CDs) is a solution for the application of such essential oils. RESULTS The complexation of carvacrol and thymol with hydroxypropyl (HP)‐α‐, HP‐β‐ and HP‐γ‐CD, the behavior of the solid complexes prepared by freeze‐drying and spray‐drying methods and the antibacterial activity of solid complexes were studied. Kc values of HP‐α‐ and HP‐γ‐CD complexes with carvacrol (118.4 and 365.7 L mol−1) and thymol (112.5 and 239.7 L mol −1) were far lower than those observed for HP‐β‐CD complexes with carvacrol (2268.2 L mol −1) and thymol (881.6 L mol −1). The lower stability of HP‐α‐ and HP‐γ‐CD complexes increased the release of compounds, thereby affecting the antimicrobial activity of carvacrol and thymol to a lesser extent than complexation with HP‐β‐CD, normally used in the encapsulation of carvacrol and thymol. HP‐β‐CD encapsulation of carvacrol and thymol markedly reduced their antimicrobial activity. The freeze‐drying method barely affected the antimicrobial activity of carvacrol and thymol after encapsulation, while spray drying could be considered for the production of solid complexes in combination with the appropriate CD. CONCLUSIONS It was thus demonstrated that HP‐α‐ and HP‐γ‐CD are very suitable alternatives for the encapsulation of carvacrol and thymol with the purpose of preserving their bacteriostatic and bactericidal activities

Concurrence of fatigue and potentiation after a sustained maximal voluntary contraction

El objetivo del presente estudio fue analizar la concurrencia e interacción existente entre diferentes factores que afectan al rendimiento, tales como son la fatiga central, la fatiga periférica y la potenciación post-activación (PPA) tras la realización de una contracción máxima voluntaria (CMV) sostenida hasta la pérdida del 50% en los valores de fuerza iniciales. Con el objetivo de valorar los efectos de la fatiga central, fatiga periférica y la PPA se utilizó la técnica de interpolación de descargas. Los resultados han revelado pérdidas en los valores de durante aproximadamente 3´30´´ y que la fatiga dependió tanto de factores centrales como periféricos. También se produjo una inhibición de la PPA tras la realización de la CMV sostenida, durante un breve periodo de tiempo (entre 30´´ y 1´30´´). Además, se observó la coexistencia de los distintos fenómenos estudiados, que sin embargo, demostraron tener una curva de recuperación temporal diferenteThe aim of the present study was to analyze the concurrence and interaction between different factors affecting the performance, such as central fatigue, peripheral fatigue and post-activation potentiation (PAP) after the performance of a maximal voluntary contraction (MVC) sustained until the loss of the 50% of the initial torque value. In order to assess the effects of central fatigue, peripheral fatigue and the PAP on the performance of the MVC, the twitch interpolation technique was used. Our findings revealed a loss of the force capability during at least 3'30'' and that the recorded fatigue had central and peripheral contributions. Moreover, it has been observed an inhibition of the PAP after the completion of the sustained MVC during a brief interval (between 30´´ and 1´30´´). Furthermore, it has been observed the coexistence of the different studied phenomena, however, they showed different time course of the recover

Herbage Mass and \u3cem\u3ein Situ\u3c/em\u3e Dry Matter Ruminal Degradation Kinetics of \u3cem\u3eBrachiaria\u3c/em\u3e spp

In Puerto Rico, Brachiaria decumbens cv. Basilisk has been promoted as a potential forage for acid soils and humid areas, but with limited success. Recently, B. brizantha cv. Marandú and a hybrid (B. brizantha x B. Ruziziensis) cv. Mulato were introduced for evaluation on acid soils and as a potential replacement for cv. Basilisk, but little information is available on yield performance under grazing or nutritive value. The objective of this study was to assess herbage mass and nutritive value of grazed pastures consisting of Basilisk, Marandú, and Mulato and determine the rate of in situ dry matter degradation

Optimization and validation of a new microbial inhibition test for the detection of antimicrobial residues in living animals intended for human consumption

Even though antibiotics are necessary in livestock production, they can be harmful not only due to their toxicity, but also in view of their contribution to the emergence of antimicrobial resistance. Screening tests based on microbial growth inhibition appeared to be useful tools to prevent its entry into the food chain. They have nevertheless been traditionally carried out post mortem, leading to great economical loss and harm to the environment in case a positive sample is found. Hence, the objective was to evaluate the use of a screening test as an ante mortem alternative for the detection of antibiotic residues in meat: thus, Explorer®-Blood test was optimized and validated. After adapting the procedure for matrix preparation, the assay parameters were assessed from 344 antibiotic-free blood serum samples. Limits of Detection (LoDs) were defined by spiking blood serum with several of the most common antimicrobials used in veterinary practice. LoDs were similar to those obtained for meat and were at or below the maximum residue limits set by EU legislation for muscle. Analyses of in vivo injected samples, previously characterized by LC-MS/MS, demonstrated the method’s accuracy and proved that Explorer®-Blood can be considered a suitable alternative to conventional post mortem screening methods

Kinetics Study of the Hydrodeoxygenation of Xylitol over a ReO\u3csub\u3ex\u3c/sub\u3e-Pd/CeO\u3csub\u3e2\u3c/sub\u3e Catalyst

In this study, we elucidate the reaction kinetics for the simultaneous hydrodeoxygenation of xylitol to 1,2-dideoxypentitol and 1,2,5-pentanetriol over a ReOx-Pd/CeO2 (2.0 weight% Re, 0.30 weight% Pd) catalyst. The reaction was determined to be a zero-order reaction with respect to xylitol. The activation energy was elucidated through an Arrhenius relationship as well as non-Arrhenius kinetics. The Arrhenius relationship was investigated at 150–170◦ C and a constant H2 pressure of 10 bar resulting in an activation energy of 48.7 ± 10.5 kJ/mol. The investigation of non-Arrhenius kinetics was conducted at 120–170◦ C and a sub-Arrhenius relation was elucidated with activation energy being dependent on temperature, and ranging from 10.2–51.8 kJ/mol in the temperature range investigated. Internal and external mass transfer were investigated through evaluating the Weisz–Prater criterion and the effect of varying stirring rate on the reaction rate, respectively. There were no internal or external mass transfer limitations present in the reaction

Kinetics Study of the Hydrodeoxygenation of Xylitol over a ReO\u3csub\u3ex\u3c/sub\u3e-Pd/CeO\u3csub\u3e2\u3c/sub\u3e Catalyst

In this study, we elucidate the reaction kinetics for the simultaneous hydrodeoxygenation of xylitol to 1,2-dideoxypentitol and 1,2,5-pentanetriol over a ReOx-Pd/CeO2 (2.0 weight% Re, 0.30 weight% Pd) catalyst. The reaction was determined to be a zero-order reaction with respect to xylitol. The activation energy was elucidated through an Arrhenius relationship as well as non-Arrhenius kinetics. The Arrhenius relationship was investigated at 150–170◦ C and a constant H2 pressure of 10 bar resulting in an activation energy of 48.7 ± 10.5 kJ/mol. The investigation of non-Arrhenius kinetics was conducted at 120–170◦ C and a sub-Arrhenius relation was elucidated with activation energy being dependent on temperature, and ranging from 10.2–51.8 kJ/mol in the temperature range investigated. Internal and external mass transfer were investigated through evaluating the Weisz–Prater criterion and the effect of varying stirring rate on the reaction rate, respectively. There were no internal or external mass transfer limitations present in the reaction

Phenotypic heterogeneity in Pseudomonas syringae

The notion of isogenic bacterial populations displaying phenotypic differences is widely accepted today. A particular case of phenotypic heterogeneity is bistability. Bistability occurs when bacterial population splits into two subpopulations showing distinct phenotypes. Phenotypic heterogeneity can allow some individuals to survive sudden environmental changes (risk-spreading) and can also lead to the cooperation (division of labour) between individuals. The relevance of this process has been highlighted in some animal pathogens, nevertheless, little is known about the occurrence or impact of these processes in the adaptation of bacteria to non-animal hosts. Pseudomonas syringae is a plant-pathogenic bacterium whose virulence depend of the T3SS expression. We have reported that T3SS expression is bistable in hrp-induction medium. This bistability generates two subpopulations, that show differences in virulence. Flagella is also an important virulence determinant for Pseudomonas syringae colonization. Here, we show how flagella expression also displays markedly phenotypic heterogeneity during growth within the plant. Although subpopulations displaying flagONT3SSON and flagOFFT3SSOFF can be identified within the plant, we provide evidence of cross regulation between T3SS and flagella expression at the individual cell level and propose phenotypic heterogeneity as an adaptative value for Pseudomonas adaptation to the plant host.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Extreme hydrological changes in the southwestern US drive reductions in water supply to Southern California by mid century

The Southwestern United States has a greater vulnerability to climate change impacts on water security due to a reliance on snowmelt driven imported water. The State of California, which is the most populous and agriculturally productive in the United States, depends on an extensive artificial water storage and conveyance system primarily for irrigated agriculture, municipal and industrial supply and hydropower generation. Here we take an integrative high-resolution ensemble modeling approach to examine near term climate change impacts on all imported and local sources of water supply to Southern California. While annual precipitation is projected to remain the same or slightly increase, rising temperatures result in a shift towards more rainfall, reduced cold season snowpack and earlier snowmelt. Associated with these hydrological changes are substantial increases in the frequency and the intensity of both drier conditions and flooding events. The 50 year extreme daily maximum precipitation and runoff events are 1.5–6 times more likely to occur depending on the water supply basin. Simultaneously, a clear deficit in total annual runoff over mountainous snow generating regions like the Sierra Nevada is projected. On one hand, the greater probability of drought decreases imported water supply availability. On the other hand, earlier snowmelt and significantly stronger winter precipitation events pose increased flood risk requiring water releases from control reservoirs, which may potentially decrease water availability outside of the wet season. Lack of timely local water resource expansion coupled with projected climate changes and population increases may leave the area in extended periods of shortages

Bistable expression of relevant genes for Pseudomonas syringae virulence

Backgrounds Heterogeneity or phenotypic variation has been known to take place in microbial clonal populations for decades. Under certain regulatory circuits, heterogeneity in gene expression can be enhanced leading to a bimodal expression profile in homogeneous environments. This process is known as bistability. The relevance of these processes has been demonstrated in Salmonella enterica and other human pathogen in the establishment of antibiotic persistence, and it has been shown to affect virulence genes, and to be linked to the establishment of chronic persistence. Nevertheless, little is known about the occurrence or impact of these processes in the adaptation of bacteria to non-animal host. Objectives To address the question of whether there is phenotypic heterogeneity in the expression of genes relevant for adaptation to a non-animal host of the model plant pathogen Pseudomonas syringae. Methods Transcriptional chromosome-located fusion to reporter genes encoding fluorescent protein were constructed in P. syringae pv. phaseolicola. Genes selected were several encoding different elements of a type III secretion system (T3SS) and flagellin, since motility has been reported as counter-regulated with the T3SS, Expression from these genes was analyzed using single-cell analysis methods, such as flow cytometry and fluorescent microscopy. Conclusions We recently showed expression of T3SS genes is phenotypically heterogeneous in planta and becomes bistable under certain laboratory conditions through the action of a double regulatory loop on the transcriptional activator HrpL. We present here single cell analyses of the gene encoding flagellin, as well as its responses to different regulatory proteins.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec