Novel materials based on DNA‐CTMA and lanthanide (Ce3+, Pr3+)

New, deoxyribonucleic acid (DNA) based compounds, functionalized with hexadecyltrimethylammonium chloride (CTMA) and lanthanide hydroxide nanoparticles were synthesized. The spectral measurements suggest that between the DNA‐CTMA complex and the lanthanide (III) ions a chemical interaction takes place. The obtained materials exhibit an improved fluorescence efficiency, showing a potential interest for application in photonics, and more particularly, in light emitting devices. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 613–617, 2016.     

MyROOT: a method and software for the semiautomatic measurement of primary root length in Arabidopsis seedlings

Root analysis is essential for both academic and agricultural research. Despite the great advances in root phenotyping and imaging, calculating root length is still performed manually and involves considerable amounts of labor and time. To overcome these limitations, we developed MyROOT, a software for the semiautomatic quantification of root growth of seedlings growing directly on agar plates. Our method automatically determines the scale from the image of the plate, and subsequently measures the root length of the individual plants. To this aim, MyROOT combines a bottom‐up root tracking approach with a hypocotyl detection algorithm. At the same time as providing accurate root measurements, MyROOT also significantly minimizes the user intervention required during the process. Using Arabidopsis, we tested MyROOT with seedlings from different growth stages and experimental conditions. When comparing the data obtained from this software with that of manual root measurements, we found a high correlation between both methods (R² = 0.997). When compared with previous developed software with similar features (BRAT and EZ‐Rhizo), MyROOT offered an improved accuracy for root length measurements. Therefore, MyROOT will be of great use to the plant science community by permitting high‐throughput root length measurements while saving both labor and time.     

Leaf litter stoichiometry affects decomposition rates and nutrient dynamics in tropical forests under restoration in Costa Rica

Active restoration strategies increase the production of leaf litter in tropical forests, but little is known about their effect on litter decomposition and subsequent nutrient release. We quantified changes in leaf litter stoichiometry during decomposition in former pasture sites under contrasting restoration strategies (natural regeneration, applied nucleation/islands tree planting and plantation), as well as in nearby primary forest. Litterbags were employed to evaluate decomposition. We used a leaf mixture of either the four planted tree species in the plantation and island treatments or the nearby primary forest and compared them under a factorial design. Decomposition rates were similar between restoration treatments (p > 0.5), but leaves decomposed faster in the forest mixture than in the plantation mixture (p < 0.01). The content of Ca, Mg, K, P, and the C:N ratio were higher in the forest mixture at the beginning and during decomposition (p < 0.05); the N content in the plantation mixture was higher at the beginning but lower during decomposition (p < 0.05), which meant greater mobilization of nitrogen per unit of carbon lost. K and P had a strong initial release, while Mg was released more gradually. N and Ca had an irregular pattern of initial fast release, immobilization, and re‐release in the later stages. We conclude that the differences in rates of decomposition and nutrient release in these systems under restoration were at least partly determined by the floristic heterogeneity and chemical quality of the leaf litter that reaches the soil.     

Organization Environmental Footprint through Input‐Output Analysis: A Case Study in the Construction Sector

The implementation of global sustainability has gained worldwide attention in recent years. The Organization Environmental Footprint, which encompasses 14 impact categories, is a multicriteria measure of the environmental performance of goods and services provided by an organization from a life cycle perspective. In this article, the focus is on quantifying the Organization Environmental Footprint of a construction company in Spain. By applying an environmentally extended input‐output approach, its total footprint and impacts along the supply chain from two consecutive years were calculated. The results show that the environmental impacts from the second year of implementation were significantly higher than those from the first year. The impact category climate change was found to have experienced the greatest increase from one year to the other, with a 31% increase. This work provides an overview of 14 environmental impact categories of the company assessed, as well as recommendations for the implementation of this indicator in companies and public procurement. This approach could pave the way to shape organizations’ action plans and meet the European environmental challenges.     

Enhanced preparation of adeno-associated viral vectors by using high hydrostatic pressure to selectively inactivate helper adenovirus

Gene delivery vectors based on adeno-associated virus (AAV) have significant therapeutic potential, but much room for improvement remains in the areas of vector engineering and production. AAV production requires complementation with either helper virus, such as adenovirus, or plasmids containing helper genes, and helper virus-based approaches have distinct advantages in the use of bioreactors to produce large quantities of AAV vectors for clinical applications. However, helper viruses must eventually be inactivated and removed from AAV preparations to ensure safety. The current practice of thermally inactivating adenovirus is problematic as it can also inactivate AAV. Here, we report a novel method using high hydrostatic pressure (HHP) to selectively and completely inactivate helper adenovirus without any detectable loss of functional AAV vectors. The pressure inactivation kinetics of human adenovirus serotype 5 and the high-pressure stabilities of AAV serotypes 2 and 5 (AAV2, AAV5), which were previously unknown, were characterized. Adenovirus was inactivated beyond detection at 260 MPa or higher, whereas AAV2 was stable up to approximately 450 MPa, and surprisingly, AAV5 was stable up to at least 700 MPa. The viral genomic DNA of pressure-inactivated AAV2 was made sensitive to DNAse I digestion, suggesting that gross changes in particle structure had occurred, and this hypothesis was further supported by transmission electron microscopy. This approach should be useful in the laboratory- and clinical-scale production of AAV gene delivery vectors. Moreover, HHP provides a tool for probing the biophysical properties of AAV, which may facilitate understanding and improving the functions of this important virus.     

Reclassification of aortic stenosis by fusion of echocardiography and computed tomography in low-gradient aortic stenosis

Netherlands Heart Journal - The integration of computed tomography (CT)-derived left ventricular outflow tract area into the echocardiography-derived continuity equation results in the...     

Molecular Insights on the Release of Avibactam from the Acyl-Enzyme Complex

Avibactam is a non-β-lactam β-lactamase inhibitor for treating complicated urinary tract and respiratory infections caused by multidrug-resistant bacterial pathogens, a serious public health threat. Despite its importance, the release mechanism of avibactam from the enzyme-inhibitor complex has been scarcely studied from first principles, considering the total protein environment. This information at the molecular level is essential for the rational design of new antibiotics and inhibitors. In this article, we addressed the release of avibactam from the complex CTX-M-15 by means of molecular dynamics simulations and quantum mechanics/molecular mechanics calculations. This study provides molecular information not available earlier, including exploration of the potential energy surfaces, characterization of the observed intermediate, and their critical points, as well. Our results show that unlike that observed in the acylation reaction, the residues Glu166 and Lys73 would be in their neutral forms. Release of avibactam follows a stepwise mechanism in which the first stage corresponds to the formation of a tetrahedral intermediate, whereas the second stage corresponds to the cleavage of the Ser70-C7 bond, mediated by Lys73, either directly or through Ser130.     

Spontaneous meningoencephalitis by Staphylococcus aureus in an infant golden‐headed lion tamarin (Leontopithecus chrysomelas)

Non‐human primates are susceptible to many bacteria, some of which bear zoonotic potential. We report the pathologic features of spontaneous fulminating meningoencephalitis by Staphylococcus aureus in a captive infant golden‐headed lion tamarin (Leontopithecus chrysomelas) from Brazil.