An Exploration of the Transformation of the 8-Oxo-7,8-Dihydroguanine Radical Cation to Protonated 2-Amino-5-Hydroxy-7,9-Dihydropurine-6,8-Dione in a Base Pair.

A theoretical investigation was performed to disclose the transformation mechanism of 8-oxo-7,8-dihydroguanine radical cation (8-oxoG⋅+ ) to protonated 2-amino-5-hydroxy-7,9-dihydropurine-6,8-dione (5-OH-8-oxoG) in base pair. The energy profiles for three possible pathways of the events were mapped. It is shown that direct loss of H7 from base paired 8-oxoG⋅+ is the only energetically favorable pathway to generate neutral radical, 8-oxoG(-H7)⋅. Further oxidation of 8-oxoG(-H7)⋅ : C to 8-oxoG(-H7)+ : C is exothermic. However, the 8-oxoG(-H7)+ : C deprotonation from all possible active sites is infeasible, indicating the inaccessible second proton loss and the lack of essential intermediate 2-amino-7,9-dihydropurine-6,8-dione (8-oxoGOX ). This makes 8-oxoG(-H7)+ act as the precursor of hydration leading to the generation of protonated 5-HO-8-oxoG by stepwise fashion in base pair, which would initiate the step down guanidinohydantoin (Gh) pathway. These results clearly specify the structure-dependent transformation for 8-oxoG⋅+ and verify the emergence of protonated 5-HO-8-oxoG in base pair.

The possibilities and limits of insurance as governance in insuring pandemics.

Insurance can, as has clearly been indicated in the literature, play an important role in dealing with catastrophe risks, not only as a compensation mechanism but also as a mechanism to influence the behaviour of the insured. It is the concept known as 'insurance as governance'. However, we argue that there are limited possibilities for this role as far as the insurance of pandemics is concerned. The traditional technical tools, such as risk-based pricing, are difficult to apply. In addition, there may, ab initio, be serious problems in insuring pandemics within one of the main conditions of insurability (controlling moral hazard through an effective risk differentiation). One remedy that is traditionally applied, more particularly for natural catastrophes, is mandatory coverage. Furthermore, the capacity problem might potentially be solved through a multilayered approach in which, in addition to insurance and reinsurance, the government could also take up a role as reinsurer of last resort. That would also have the major advantage of stimulating market solution (and potentially providing incentives for the mitigation of damages), which clearly fails in a model where the government simply bails out operators. Finally, one important regulatory intervention is that insurers should be better informed than was apparently the case during the last pandemic about exactly which type of risks are covered and which are not.

Responses of microbial communities to the addition of different types of microplastics in agricultural soils.

A 90-day soil incubation study was performed to investigate impacts of four types (PE, PP, PVC and PET) of microplastics (MPs) on the physicochemical properties, nutrient contents, enzyme activities, and microbial community structure and diversity of agricultural soils. Effects of the four microplastic types and addition ratios on the microbiology of the agricultural soils were significant. With the addition of MPs, there was a positive correlation between physicochemical properties, nutrients (AN, AP, AK) and enzyme activities (CAT, Urease, ACP, SUC), which were all decreased to some extent. Overall PE and PVC surfaces were the roughest and had the greatest impact on soil physicochemical properties, nutrients and enzyme activities. The changes in soil microbial α-diversity were not significant (P > 0.05), but, PP and PVC led to an increase in community diversity and abundance. Clearly, the four types of the MPs reduced the physicochemical properties, nutrient content, enzyme activity and microbial community, and thus significantly affected the microbiology of the farmland soils.

Single molecule study of DNA collision with elliptical nanoposts conveyed by hydrodynamics.

Periodic arrays of micro- or nanopillars constitute solid-state matrices with excellent properties for DNA size separation. Nanofabrication technologies offer many solutions to tailor the geometry of obstacle arrays, yet most studies have been conducted with cylinders arranged in hexagonal lattices. In this report, we investigate the dynamics of single DNA collision with elliptical nanoposts using hydrodynamic actuation. Our data show that the asymmetry of the obstacles has minor effect on unhooking dynamics, and thus confirm recent predictions obtained by Brownian dynamics simulations. In addition, we show that the disengagement dynamics are correctly predicted by models of electrophoresis, and propose that this consistency is associated to the confinement in slit-like channels. We finally conclude that elliptical posts are expected to marginally improve the performances of separation devices.

RNA-Seq Analysis of Aboveground and Underground Parts of Biomass Sorghum Was Performed to Evaluate Its Suitability for Environmental Remediation.

"Alto2" is a new biomass sorghum variety, which has the characteristics of fast growth, high growth, and strong cadmium (Cd) resistance, so it has the application prospect of soil remediation plants. In order to reveal the Cd resistance mechanism of this plant and pave the way for genetic breeding and cultivation of efficient remediation plants in the future, in this research, through the determination of Cd content in various tissues of sorghum under Cd stress and the physicochemical response combined with RNA-Seq analysis, the mechanism of Cd resistance of "Alto2" was initially revealed. The results show biomass sorghum "Alto2" was mainly connected with aboveground and underground parts through the MAPK signaling pathway and plant hormone signaling pathway, and transmit stress signal in response to Cd stress. Chelase and metal-binding proteins may be the functional genes mainly responsible for Cd enrichment and transport and regulated by stress signals. However, the expression of aboveground transporters was not significant. This may be because Cd in biomass sorghum is mainly concentrated in the underground part and is enriched by the chelation of secondary metabolites from plant roots by the cell wall leading to inhibition of aboveground transporter expression. The results of this study indicate that the biomass sorghum "Alto2" on Cd has high resistance, but the lack of the aboveground enrichment of transportability requires further research to improve the Cd transportability of this plant.

Hydrodynamic manipulation of DNA in nanopost arrays: unhooking dynamics and size separation.

Micro- or nanofabricated obstacle arrays are widely used as model matrices to perform fast DNA separations by electrophoresis. In this report, a gallery of obstacles of radii spanning from 40 to 250 nm are used to investigate the dynamics of hydrodynamic-field-driven DNA-nanopost collisions at the single-molecule level. The data shows that DNA disengagement dynamics are reasonably well described by conventional electrophoretic models in the limit of a large spacing between obstacles and for moderate migration velocities. It is also demonstrated that the use of hydrodynamic flow fields to convey DNA molecules is associated with changes in the configurational space of hooking events, and to altered relaxation dynamics between consecutive collisions. This study defines experimental conditions for the efficient separation of DNA fragments of tens of base pairs, and provides a complete framework by which to understand the behavior of DNA in the course of hydrodynamic-driven migrations through nanopost arrays.

Directed assembly of nanoparticles along predictable large-scale patterns using micromolded hydrogels.

We present a new technology to organize microparticles and nanoparticles along micropatterns of variable complexity over centimeter-squared surfaces. This technology relies on the fabrication of textured hydrogels, which serve as templates for directed assembly after the deposition of a droplet of colloids on their surfaces. We show that directed assembly occurs spontaneously during water evaporation, and we demonstrate the efficiency of this mechanism for a variety of organic and inorganic nano-objects. The dynamics of this process is also uncovered by light microscopy, showing that the patterns imprinted on the gel determine fluid flow during water evaporation and allow for directed movements toward predictable positions. We finally propose different methods to transfer assembled particles from hydrogels to glass, silicon, or metallic surfaces, and we show that the assembled and transferred particles retain their surface properties for bioassays. Beyond the originality of this spontaneous assembly mechanism, it constitutes an attractive technology for nano-object large-scale integration, which does not require costly environmental control equipment.

Transcriptome Profiles of Leaves and Roots of Goldenrain Tree (Koelreuteria paniculata Laxm.) in Response to Cadmium Stress.

Cadmium (Cd) pollution is a widespread environmental problem. In this study, we explored the transcriptome and biochemical responses of goldenrain tree (Koelreuteria paniculata Laxm.) leaves and roots to Cd stress. Leaf and root growth decreased substantially under Cd stress (50 mg/L CdCl2), but leaf and root antioxidant mechanisms were significantly activated. In RNA-seq analysis, roots treated with 25 mg/L CdCl2 featured enriched GO terms in cellular components related to intracellular ribonucleoprotein complex, ribonucleoprotein complex, and macromolecular complex. In leaves under Cd stress, most differentially expressed genes were enriched in the cellular component terms intrinsic component of membrane and membrane part. Weighted gene co-expression network analysis and analysis of module-trait relations revealed candidate genes associated with superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities and malondialdehyde (MDA). Ten transcription factors responded to Cd stress expression, including those in C2H2, MYB, WRKY, and bZIP families. Transcriptomic analysis of goldenrain tree revealed that Cd stress rapidly induced the intracellular ribonucleoprotein complex in the roots and the intrinsic component of membrane in the leaves. The results also indicate directions for further analyses of molecular mechanisms of Cd tolerance and accumulation in goldenrain tree.