Labile Cd complexes increase Cd availability to plants

Dissolved trace metals are present in the environment as free ions and as complexes. Commonly used models to predict metal bioavailability consider the free ion as the major bioavailable species. However, increases in metal availability in the presence of metal complexes have repeatedly been found. We measured the uptake of cadmium (Cd) by spinach (Spinacia oleracea) from solution in absence or presence of synthetic ligands. At the same free ion concentration, the uptake of Cd ranged over almost 3 orders of magnitude and was largest in treatments with fast dissociating (i.e. labile) complexes. Similar results were found for the diffusional fluxes in these solutions, as measured with the DGT technique. The observed effect of Cd complexes on the plant uptake was in agreement with model calculations in which plant uptake was assumed to be governed by the diffusional flux. These results strongly suggest that Cd uptake is rate-limited by diffusion of the free ion to the root surface, even in stirred solutions. As a result, dissolved Cd complexes can increase Cd uptake, resulting in apparent exceptions from the free ion activity model. The magnitude of this increase depends both on the concentration and on the lability of the complexes. The free ion concept should therefore be reconsidered when transport limitations of the metal ion to the uptake site prevail.     

Fecal bacteria in the rivers of the Seine drainage network (France): sources, fate and modelling

The Seine river watershed (France) is a deeply anthropogenically impacted area, due to the high population density, intense industrial activities and intensive agriculture. The water quality and ecological functioning of the different rivers of the Seine drainage network have been extensively studied during the last fifteen years within the framework of a large French multidisciplinary scientific program (PIREN Seine program). This paper presents a synthesis of the main data gained in the scope of this program concerning the microbiological water contamination of the rivers of the Seine drainage network. The more common indicator of fecal contamination (fecal coliforms) was mainly used; some complementary works used E. coli and intestinal enterococci as alternative fecal indicators. Point sources (outfall of wastewater treatment plants) and non point sources (surface runoff and soil leaching) of fecal pollution to the rivers of the watershed were quantified. Results showed that, at the scale of a large urbanised watershed as the Seine basin, the input of fecal micro-organisms by non-point sources is much lower than the inputs by point sources. However, the local impact of diffuse non-human sources (especially surface runoff of pastured fields) can be of major importance on the microbiological quality of small headwater rivers. Fecal contamination of the main rivers of the Seine watershed (Seine, Marne, Oise rivers) was studied showing high level of microbiological pollution when compared to European guidelines for bathing waters. The strong negative impact of treated wastewater effluents outfall on the microbiological quality of receiving rivers was observed in different areas of the watershed. Once released in rivers, culturable fecal bacteria disappeared relatively rapidly due to mortality (protozoan grazing, lysis) or loss of culturability induced by stress conditions (sunlight effect, nutrient concentration, temperature). Mortality rates of E. coli were studied in different types of rivers within the watershed showing, in summer conditions, no major difference in the mortality rates in small and large rivers. As a result of these studies, a module describing the dynamics of fecal bacteria has been developed and embedded within a hydro-ecological model describing the functioning of the rivers of the whole watershed (the SENEQUE model). Once validated, such a model can be used for testing predictive scenarios and thus can be a very useful tool for the management of microbiological water quality at the scale of the whole basin.     

Preparation and evaluation of Co/Al2O3 catalysts in the production of hydrogen from thermo-catalytic decomposition of methane: Influence of operating conditions on catalyst performance

This paper presents the synthesis of Co-doped Al₂O₃ catalysts, developed by our group, with porous structures and high surface areas. The catalytic activity of the materials obtained was evaluated in the catalytic decomposition of methane, which is an attractive method for CO/CO₂-free production of hydrogen, particularly for fuel cell applications.The catalysts were shown to be active and stable in relation to the catalytic decomposition of methane reaction. It was observed that the catalytic performance is dependent on the catalyst characteristics and on the operational conditions employed.The conversion of methane increased with metal loading, reaction temperature and N₂:CH₄ molar ratio.     

Histone Extraction from Human Articular Cartilage for the Study of Epigenetic Regulation in Osteoarthritis

Osteoarthritis (OA) is a chronic disease that affects articular cartilage, causing its degeneration. Although OA is one of the most prevalent pathologies globally, there are no definitive treatments available. Recently, research has focused on elucidating the complex interplay that takes place between inflammatory processes and epigenetic regulation, showing that histone post-translational modifications (PTMs) can exert a pronounced effect on the expression of OA-related genes. OA chondrocytes enhance the production of interleukin 1β (IL-1β) and interleukin 8 (IL-8), which are epigenetically regulated. These cytokines upregulate the synthesis of matrix metalloproteinases (MMPs) and aggrecanases, which promote the extracellular matrix (ECM) destruction. This motivates the study of histone PTMs to investigate the epigenetic regulation of proinflammatory molecules, but the absence of specific protocols to extract histones from human articular cartilage has complicated this task. The lack of effective methods can be explained by the structural complexity and low cellularity of this tissue, which are responsible for the biomechanical properties that allow the movement of the joint but also complicate histone isolation. Here, we provide a histone extraction procedure specifically adapted for cryopreserved human articular cartilage that can be useful to understand epigenetic regulation in OA and accelerate the search for novel strategies.     

Biocompatible Materials in Otorhinolaryngology and Their Antibacterial Properties

For decades, biomaterials have been commonly used in medicine for the replacement of human body tissue, precise drug-delivery systems, or as parts of medical devices that are essential for some treatment methods. Due to rapid progress in the field of new materials, updates on the state of knowledge about biomaterials are frequently needed. This article describes the clinical application of different types of biomaterials in the field of otorhinolaryngology, i.e., head and neck surgery, focusing on their antimicrobial properties. The variety of their applications includes cochlear implants, middle ear prostheses, voice prostheses, materials for osteosynthesis, and nasal packing after nasal/paranasal sinuses surgery. Ceramics, such as as hydroxyapatite, zirconia, or metals and metal alloys, still have applications in the head and neck region. Tissue engineering scaffolds and drug-eluting materials, such as polymers and polymer-based composites, are becoming more common. The restoration of life tissue and the ability to prevent microbial colonization should be taken into consideration when designing the materials to be used for implant production. The authors of this paper have reviewed publications available in PubMed from the last five years about the recent progress in this topic but also establish the state of knowledge of the most common application of biomaterials over the last few decades.     

Polycaprolactone primers with zinc oxide and silicon dioxide nanoparticles for paper substrates: Influence on the properties of cyan and magenta offset prints

In this research study, the applicability of polycaprolactone‐silicon dioxide and polycaprolactone‐zinc oxide coatings used as primers on papers for offset printing, was analysed. Polycaprolactone nanocomposites with different concentrations of nanoparticles were prepared and coated onto three types of papers: uncoated, low‐coated and gloss. The main aim was to analyse the influence of the nanoparticle concentration in primer on the optical and colorimetric properties of cyan and magenta offset printed samples. To further evaluate the applicability of the primers, the tensile strength of primed samples and their surface properties were analysed. Results show that prepared primers are primarily applicable on uncoated and low coated papers. Both nanoparticles in specific concentrations increased gloss values for printed samples on low‐coated paper, and the addition of both types of nanoparticles increased the rub resistance of printed samples. Furthermore, for each type of nanoparticle, the optimal concentration at which the colour deviation on print was minimised could be defined. Adding nanoparticles to primers did not significantly improve mottling on cyan‐printed samples. However, by increasing the concentration of nanoparticles in the primer by up to 1%, the mottling on magenta‐printed samples decreased.     

Human Brain Models of Intellectual Disability: Experimental Advances and Novelties

Intellectual disability (ID) is characterized by deficits in conceptual, social and practical domains. ID can be caused by both genetic defects and environmental factors and is extremely heterogeneous, which complicates the diagnosis as well as the deciphering of the underlying pathways. Multiple scientific breakthroughs during the past decades have enabled the development of novel ID models. The advent of induced pluripotent stem cells (iPSCs) enables the study of patient-derived human neurons in 2D or in 3D organoids during development. Gene-editing tools, such as CRISPR/Cas9, provide isogenic controls and opportunities to design personalized gene therapies. In practice this has contributed significantly to the understanding of ID and opened doors to identify novel therapeutic targets. Despite these advances, a number of areas of improvement remain for which novel technologies might entail a solution in the near future. The purpose of this review is to provide an overview of the existing literature on scientific breakthroughs that have been advancing the way ID can be studied in the human brain. The here described human brain models for ID have the potential to accelerate the identification of underlying pathophysiological mechanisms and the development of therapies.     

Microglial CD74 Expression Is Regulated by TGFβ Signaling

Simple SummaryIn the present study, we provided evidence that TGFβ signaling regulated the expression of the microglia activation marker CD74. Our data demonstrated that TGFβ1 inhibited LPS-induced upregulation of CD74. Moreover, inhibition of microglial TGFβ signaling in vitro and silencing of TGFβ signaling by deletion of Tgfbr2 in vivo resulted in marked upregulation of microglial CD74.AbstractMicroglia play important roles during physiological and pathological situations in the CNS. Several reports have described the expression of Cd74 in disease-associated and aged microglia. Here, we demonstrated that TGFβ1 controled the expression of Cd74 in microglia in vitro and in vivo. Using BV2 cells, primary microglia cultures as well as Cx3cr1^CreERT2:R26-YFP:Tgfbr2^fl/fl in combination with qPCR, flow cytometry, and immunohistochemistry, we were able to provide evidence that TGFβ1 inhibited LPS-induced upregulation of Cd74 in microglia. Interestingly, TGFβ1 alone was able to mediate downregulation of CD74 in vitro. Moreover, silencing of TGFβ signaling in vivo resulted in marked upregulation of CD74, further underlining the importance of microglial TGFβ signaling during regulation of microglia activation. Taken together, our data indicated that CD74 is a marker for activated microglia and further demonstrated that microglial TGFβ signaling is important for regulation of Cd74 expression during microglia activation.     

In Silico Genome-Scale Analysis of Molecular Mechanisms Contributing to the Development of a Persistent Infection with Methicillin-Resistant Staphylococcus aureus (MRSA) ST239

The increasing frequency of isolation of methicillin-resistant Staphylococcus aureus (MRSA) limits the chances for the effective antibacterial therapy of staphylococcal diseases and results in the development of persistent infection such as bacteremia and osteomyelitis. The aim of this study was to identify features of the MRSA_ST239 0943-1505-2016 (SA943) genome that contribute to the formation of both acute and chronic musculoskeletal infections. The analysis was performed using comparative genomics data of the dominant epidemic S. aureus lineages, namely ST1, ST8, ST30, ST36, and ST239. The SA943 genome encodes proteins that provide resistance to the host’s immune system, suppress immunological memory, and form biofilms. The molecular mechanisms of adaptation responsible for the development of persistent infection were as follows: amino acid substitution in PBP2 and PBP2a, providing resistance to ceftaroline; loss of a large part of prophage DNA and restoration of the nucleotide sequence of beta-hemolysin, that greatly facilitates the escape of phagocytosed bacteria from the phagosome and formation of biofilms; dysfunction of the AgrA system due to the presence of psm-mec and several amino acid substitutions in the AgrC; partial deletion of the nucleotide sequence in genomic island vSAβ resulting in the loss of two proteases of Spl—operon; and deletion of SD repeats in the SdrE amino acid sequence.     

Optimization of the n-hexane isomerization process using response surface methodology

Isomerization reactions on commercial zirconium sulfate catalyst are investigated in order to determine influence of hydrogen/feed ratio, space velocity and temperature on n-hexane conversion. Investigated range of inlet parameters includes values that are applied in the industrial practice of the isomerization process. Box–Behnken experimental design was carried out in order to optimize n-hexane isomerization process. Statistical analysis of experimental data was performed to obtain second order polynomial model and the optimum conditions were determined: hydrogen/feed ratio of 6, space velocity of 2 h⁻¹ and temperature of 170 °C. At optimum conditions conversion of n-hexane was 70 wt.%. In addition, temperature dependency of product composition was investigated at optimum values of hydrogen/feed ratio and space velocity. Obtained results show that methylpentanes greatly depend on temperature, unlike dimethylbutanes, in the studied range from 130 to 170 °C. Isomer that was produced in highest quantities was 2-methylpentane, while 3-methylpentane forms in somewhat smaller amounts. 2,2- and 2,3-dimethylbutanes, which contribute the most to the octane number value, are formed in relatively small quantities, amounting to less than 10 wt.% of the total amount of isomers formed.