Bacterial laccases: some recent advances and applications

Laccases belong to the large family of multi-copper oxidases (MCOs) that couple the one-electron oxidation of substrates with the four-electron reduction of molecular oxygen to water. Because of their high relative non-specific oxidation capacity particularly on phenols and aromatic amines as well as the lack of requirement for expensive organic cofactors, they have found application in a large number of biotechnological fields. The vast majority of studies and applications were performed using fungal laccases, but bacterial laccases show interesting properties such as optimal temperature above 50 °C, optimal pH at the neutral to alkaline range, thermal and chemical stability and increased salt tolerance. Additionally, bacterial systems benefit from a wide range of molecular biology tools that facilitates their engineering and achievement of high yields of protein production and set-up of cost-effective bioprocesses. In this review we will provide up-to-date information on the distribution and putative physiological role of bacterial laccases and highlight their distinctive structural and biochemical properties, discuss the key role of copper in the biochemical properties, discuss thermostability determinants and, finally, review biotechnological applications with a focus on catalytic mechanisms on phenolics and aromatic amines.info:eu-repo/semantics/publishedVersio

Prevalence, antimicrobial susceptibility and risk factors associated with non-typhoidal Salmonella on Ugandan layer hen farms

Abstract Background Non-typhoidal Salmonella (NTS) are among the leading global foodborne pathogens and a significant public health threat. Their occurrence in animal reservoirs and their susceptibilities to commonly used antimicrobials are poorly understood in developing countries. The aim of this study was to estimate the prevalence, determine antimicrobial susceptibility and identify risk factors associated with NTS presence in laying hen farms in Uganda through a cross-sectional study. Results Pooled faecal samples were collected from 237 laying hen farms and these were analysed for NTS following standard laboratory procedures. In total, 49 farms (20.7%; 95% Confidence interval (CI): 15.6–25.6%) were positive for NTS presence. Altogether, ten Salmonella serotypes were identified among the confirmed 78 isolates, and the predominant serotypes were Salmonella Newport (30.8%), S. Hadar (14.1%), S. Aberdeen (12.8%), S. Heidelberg (12.8%), and S. Bolton (12.8%). Phenotypic antimicrobial resistance was detected in 45(57.7%) of the isolates and the highest resistance was against ciprofloxacin (50.0%) followed by sulphonamides (26.9%) and sulphamethoxazole/trimethoprim (7.7%). Resistance was significantly associated with sampled districts (p = 0.034). Resistance to three or more drugs, multi-drug resistance (MDR) was detected in 12 (15.4%) of the isolates, 9 (75%) of these were from Wakiso district. A multivariable logistic model identified large farm size (OR = 7.0; 95% CI: 2.5–19.8) and the presence of other animal species on the farm (OR = 5.9; 95% CI: 2.1–16.1) as risk factors for NTS prevalence on farms. Having a separate house for birds newly brought to the farms was found to be protective (OR = 0,4; 95% CI: 0.2–0.8). Conclusion This study has highlighted a high prevalence and diversity of NTS species in laying hen farms in Uganda and identified associated risk factors. In addition, it has demonstrated high levels of antimicrobial resistance in isolates of NTS. This could be because of overuse or misuse of antimicrobials in poultry production. Also importantly, the insights provided in this study justifies a strong case for strengthening One Health practices and this will contribute to the development of NTS control strategies at local, national and international levels

Improving orbit prediction via thermospheric density calibration

The uncertainty on Thermospheric Mass Density (TMD), as derived from atmospheric models, can reach extremely high values. This effect is noteworthy in Low Earth Orbit (LEO), where atmospheric drag is the main perturbing force, as well as the most uncertain. LEO harbours almost 18,000 space objects at the end of 2021, around 60% of the total space debris population, and the rate of growth is increasing every year. Increasing the accuracy of TMD models, and thus the uncertainty characterisation, is important to ensure space environment sustainability in this congested and contested region. Accurate TMD modelling is a decisive factor in all space applications below the exopause, from LEO mission design to Space Situational Awareness (SSA) service provision: from conjunction assessment to re-entry and fragmentation analysis To enhance empirical TMD models, atmospheric density observations derived from satellite measurements are assimilated.This paper presents a novel approach for assimilating thermospheric density observations into atmospheric models to improve the accuracy of orbit predictions in short- to medium- term propagations. First, Global Navigation Satellite System (GNSS) derived density data from Swarm satellites are ingested from the publicly available Level 2 data products of the European Space Agency (ESA). In a second step, density data is assimilated into the empirical model NRMLSISE-00, using Principal Component Analysis (PCA) to decompose into the main temporal and spatial modes, providing useful physical insight into the main variables driving the model. Thirdly, the model is tested on several cases, whose data was not assimilated, such as LEO satellites that are well-tracked with GNSS-derived positions: Sentinel, and GRACE. The model is also tested with objects with less accurate reference trajectories, such as catalogued space debris in LEO. Finally, the orbits are propagated, using the improved drag model that includes the neutral density from the assimilation of the GNSS-derived observations into NLRMSISE-00. The accuracy of the method is assessed and compared to non-assimilated models. During the discussion of the results, other sources of uncertainty are analysed. To name a few, geomagnetic activity, solar radiation pressure coefficient, attitude knowledge, and spacecraft parameters such as mass, area, drag coefficient, and so on. The improvement on the state accuracy and uncertainty realism after a medium-term propagation is analysed and the application to catalogue maintenance discussed.<br/

Estradiol transdérmico y perfil lipídico: efectos en un grupo específico de mujeres brasileñas posmenopáusicas

FUNDAMENTO: Em mulheres pós-menopausadas, mudanças significantes ocorrem, que podem induzir doenças cardiovasculares, tais como o perfil lipídico aterogênico devido a um aumento nos níveis de colesterol total e LDL, e uma diminuição nos níveis de HDL. A terapia de reposição hormonal (TRH) pode evitar essas mudanças no perfil lipídico. OBJETIVO: Determinar os efeitos da TRH constituída por estradiol transdérmico e acetato de medroxiprogesterona nos parâmetros bioquímicos e lipídicos de mulheres brasileiras pós-menopausadas. MÉTODOS: Este é um estudo prospectivo, longitudinal, aberto, no qual trinta mulheres pós-menopausadas receberam estradiol em gel transdérmico (1 mg/dia) de forma contínua, combinado com acetato de medroxiprogesterona (MPA) (5 mg/dia) por 12 dias/mês. Os seguintes parâmetros foram determinados: colesterol total, triglicérides, lipoproteína de alta densidade (HDL-colesterol), lipoproteína de baixa densidade (LDL-colesterol), lipoproteína de muito baixa densidade (VLDL-colesterol), glicose, aspartato aminotransferase (AST), alanina aminotransferase (ALT), gama-glutamil transferase (GGT) e hormônio folículo estimulante (FSH). RESULTADOS: Os parâmetros do perfil lipídico mostraram uma diminuição não-significante, enquanto os níveis de GGT e FSH apresentaram uma diminuição estatisticamente significante. CONCLUSÕES: O tratamento com estradiol em gel transdérmico não mostrou um impacto significante no perfil lipídico, de forma que não resultou em um efeito benéfico nos marcadores de doenças cardiovasculares, sugerindo que a dose, modo de administração e o tempo de tratamento foram importantes para esses resultados. Além disso, o tratamento com dose baixa e modo de administração transdérmico também demonstrou um significante efeito hepático nessa população. Dessa forma, esse tratamento pode fornecer efeitos interessantes sobre o perfil lipídico em mulheres brasileiras pós-menopausadas.BACKGROUND: In postmenopausal women, significant changes occur that can induce cardiovascular diseases, such as atherogenic lipid profile, due to an increase in total cholesterol and LDL levels, and a decrease in HDL cholesterol levels. The hormone replacement therapy (HRT) can prevent these changes in lipid profile. OBJECTIVE: Verify the effects of HRT consisting of transdermal estradiol gel associated with medroxyprogesterone acetate on the lipid profile and biochemical parameters in Brazilian postmenopausal women. METHODS: This study is an open prospective longitudinal study, in which thirty postmenopausal women received transdermal estradiol gel (1 mg/day) continuously combined with oral medroxyprogesterone acetate (MPA) (5 mg/day) for 12 days/month. The following parameters were determined: total cholesterol, triglycerides, high density lipoprotein (HDL), low density lipoprotein (LDL), very low density lipoprotein (VLDL), glucose, aspartate aminotransferase (AST), alanine aminotransferase (ALT), gama glutamyl transferase (GGT) and follicle-stimulating hormone (FSH). RESULTS: The parameters of the lipid profile did not show a significant decrease, while the levels of GGT and FSH had a statistically significant decrease. CONCLUSIONS: the treatment with transdermal estradiol gel did not have a significant impact on the lipid profile, thus not resulting in a beneficial effect on cardiovascular disease markers, suggesting that the dose, administration route and the time of treatment were important for these results. Moreover, the treatment using small dose and the transdermal administration route also had a significant hepatic effect in this population. Therefore, this treatment might provide interesting effects on the lipid profile in Brazilian postmenopausal women.FUNDAMENTO: Cambios significantes ocurren en las mujeres posmenopáusicas que pueden inducir enfermedades cardiovasculares, tales como el perfil lipídico aterogénico debido a un aumento en los niveles de colesterol total y LDL y una disminución en los niveles de HDL. La terapia de reemplazo hormonal (TRH) puede evitar esos cambios en el perfil lipídico. OBJETIVO: Determinar los efectos de la TRH constituida por estradiol transdérmico y acetato de medroxiprogesterona en los parámetros bioquímicos y lipídicos de mujeres brasileñas posmenopáusicas MÉTODOS: Este es un estudio prospectivo, longitudinal, abierto, en el que treinta mujeres posmenopáusicas recibieron estradiol en gel transdérmico (1 mg/día) de forma continua, combinado con acetato de medroxiprogesterona (MPA) (5 mg/día) por 12 días/mes. Se determinaron los seguientes parámetros: colesterol total, triglicéridos, lipoproteína de alta densidad (HDL-colesterol), lipoproteína de baja densidad (LDL-colesterol), lipoproteína de muy baja densidad (VLDL-colesterol), glucosa, aspartato transaminasa (AST), alanina aminotransferasa (ALT), Gammaglutamiltranspeptidasa (GGT) y hormona foliculoestimulante (FSH). RESULTADOS: Los parámetros del perfil lipídico mostraron una disminución insignificante, mientras los niveles de GGT y FSH presentaron una disminución estadísticamente significante. CONCLUSIONES: El tratamiento con estradiol en gel transdérmico no mostró un impacto significante en el perfil lipídico, causando un efecto benéfico en los marcadores de enfermedades cardiovasculares, sugiriendo que la dosis, el modo de administración y el tiempo de tratamiento fueron importantes para esos resultados. Además, el tratamiento con dosis baja y modo de administración transdérmico también demostró un significante efecto hepático en esa población. Así pues, ese tratamiento puede surtir efectos interesantes sobre el perfil lipídico en las mujeres brasileñas posmenopáusicas.Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES

Effect of storage time at low temperature on the volatile compound composition of Sevillana and Maravilla raspberries

In this study, the effect of storage time at low temperature on volatile compounds in two cultivars of raspberry, Rubus idaeus L. cv. Sevillana and Maravilla, was determined. A total of 28 compounds were identified in both cultivars and showed quantitative differences between the cultivars. The Sevillana cultivar was richer in volatile compounds than the Maravilla cultivar. beta-Ionone had the highest concentration in both cultivars. We observed opposing trends in the volatile compound composition for the cultivars during storage at low temperature, in which 'Sevillana' lost compounds and 'Maravilla' was enriched. Therefore, storage at low temperature causes important changes in the volatile compound profile of raspberry, particularly the Sevillana cultivar, with significant decreases in C-13-norisoprenoids and increases in terpenes. These changes are most likely responsible for the aromatic differences between the cultivars because of the presence of terpenes in 'Sevillana' and C-13-norisoprenoids in 'Maravilla'. (C) 2014 Elsevier B.V. All rights reserved

Internalisation of hybrid titanium dioxide/para-amino benzoic acid nanoparticles in human dendritic cells did not induce toxicity and changes in their functions

Migdal, Camille Rahal, Raed Rubod, Alain Callejon, Sylvie Colomb, Evelyne Atrux-Tallau, Nicolas Haftek, Marek Vincent, Claude Serres, Mireille Daniele, StephaneInternational audienceNanoparticles (NPs) have been reported to penetrate into human skin through lesional skin or follicular structures. Therefore, their ability to interact with dendritic cell (DC) was investigated using DCs generated from monocytes (mono-DCs). Hybrid titanium dioxide/para-amino benzoic acid (TiO2/PABA) NPs did not induce any cell toxicity. NPs were internalised into DCs through macropinocytosis and not by a receptor-mediated mechanism. Confocal microscopy showed that NPs were not detected in the nucleus. These data are confirmed by electronic microscopy which demonstrated that hybrid NPs were rapidly in contact with cellular membrane and localised into cytoplasmic vesicles without colocalisation with clathrin-coated vesicles. Hybrid NPs did not induce CD86 or HLA-DR overexpression or cytokine secretion (IL-8 and TNF-alpha) indicating no DC activation. Internalisation of hybrid NPs did not modify DC response towards sensitisers such as nickel and thimerosal or LPS used as positive controls. Moreover, hybrid NPs did not induce any oxidative stress implicated in DC activation process. After mono-DC irradiation by ultraviolet A (UVA), hybrid NP-treated cells did not produce UVA-induced reactive oxygen species (ROS) and exhibited a better cell viability compared with UVA-irradiated control cells, suggesting a protecting effect of hybrid TiO2/PABA NPs against UVA-induced ROS. (C) 2010 Elsevier Ireland Ltd. All rights reserved