Computational Prediction of Coiled-Coil Protein Gelation Dynamics and Structure

Protein hydrogels represent an important and growing biomaterial for a multitude of applications, including diagnostics and drug delivery. We have previously explored the ability to engineer the thermoresponsive supramolecular assembly of coiled-coil proteins into hydrogels with varying gelation properties, where we have defined important parameters in the coiled-coil hydrogel design. Using Rosetta energy scores and Poisson-Boltzmann electrostatic energies, we iterate a computational design strategy to predict the gelation of coiled-coil proteins while simultaneously exploring five new coiled-coil protein hydrogel sequences. Provided this library, we explore the impact of in silico energies on structure and gelation kinetics, where we also reveal a range of blue autofluorescence that enables hydrogel disassembly and recovery. As a result of this library, we identify the new coiled-coil hydrogel sequence, Q5, capable of gelation within 24 h at 4 °C, a more than 2-fold increase over that of our previous iteration Q2. The fast gelation time of Q5 enables the assessment of structural transition in real time using small-angle X-ray scattering (SAXS) that is correlated to coarse-grained and atomistic molecular dynamics simulations revealing the supramolecular assembling behavior of coiled-coils toward nanofiber assembly and gelation. This work represents the first system of hydrogels with predictable self-assembly, autofluorescent capability, and a molecular model of coiled-coil fiber formation.

Carbon footprint of fertilizer technologies

The work discussed the necessity to evaluate the environmental effect - i.e. carbon footprint (CF), of N-containing fertilizers when including their production, transportation and use. For that purpose, life cycle assessment (LCA) methodology was involved. The LCA-based CF concerned model fertilizer technology determined with the consideration of greenhouse gases assimilation during fertilizer-induced vegetation, as compared to non-treated crops system. According to the available data, the inclusion of CO₂ assimilation by plants via photosynthesis in balance sheet offsets 87.6% of the CF from the biomass consumption. Thus, the new approach to LCA along with the analysis of life cycle costs would provide more reliable determination of the fee amount charged to European fertilizer manufacturers. The approach might be further developed for various products for plant treatment. Also, the verification of similar fertilizer technologies in different installations is expected to identify bottlenecks in terms of the ecological, technical and economic evaluation.

Absence of mutagenicity of trioxane and dioxolane in Salmonella typhimurium

The mutagenic activity of trioxane and dioxolane was investigated in 5 histidine-requiring strains of S. typhimurium: TA1535, TA1537, TA1538, TA98 and TA100 with and without activation by liver microsomes. They were not mutagenic under any of these conditions with any of the his- S. typhimurium tester strains (in the presence or absence of S9 mix from liver homogenate of rats induced with Aroclor 1254).

Genotoxic effects of dioxolane and trioxane in mice evaluated by the micronucleus test

The possible genotoxic effects of dioxolane and trioxane were studied using the micronucleus test. Mice were given dioxolane and trioxane i.p. in two doses at 24-h intervals. Dioxolane at doses from 1500 mg/kg to 6000 mg/kg caused a significant increase of micronucleated polychromatic erythrocytes in bone marrow of mice as compared to the negative control value. Positive results in the micronucleus test provide evidence of genotoxic activity of dioxolane. I.p. administration of trioxane produced no chromosomal damage resulting in erythrocyte micronucleus formation, even at highly toxic doses.

Genotoxic effects of ethyl acrylate and methyl acrylate in the mouse evaluated by the micronucleus test

The micronucleus test was used to study the mutagenic effects of ethyl acrylate and methyl acrylate. Investigated compounds were administered to Balb C male mice by i.p. injection in two doses, separated by a period of 24 h. Ethyl acrylate at doses of 225-1800 mg/kg, and methyl acrylate at doses of 37.5-300 mg/kg significantly induce chromosome damage resulting in micronuclei formation in bone marrow polychromatic erythrocytes. Both investigated compounds significantly decrease the ratio of polychromatic to normochromatic erythrocytes. Positive results provide evidence of clastogenic activity of ethyl acrylate and methyl acrylate.