CpSmt3, an ortholog of small ubiquitin-like modifier, is essential for growth, organelle function, virulence, and antiviral defense in Cryphonectria parasitica.

Introduction: SUMOylation is an important post-translational modification that regulates the expression, localization, and activity of substrate proteins, thereby participating in various important cellular processes such as the cell cycle, cell metabolism, gene transcription, and antiviral activity. However, the function of SUMOylation in phytopathogenic fungi has not yet been adequately explored. Methods: A comprehensive analysis composed of proteomics, affinity pull-down, molecular and cellular approaches was performed to explore the roles of SUMOylation in Cryphonectria parasitica, the fungal pathogen responsible for chestnut blight. Results and discussion: CpSmt3, the gene encoding the SUMO protein CpSmt3 in C. parasitica was identified and characterized. Deletion of the CpSmt3 gene resulted in defects in mycelial growth and hyphal morphology, suppression of sporulation, attenuation of virulence, weakening of stress tolerance, and elevated accumulation of hypovirus dsRNA. The ΔCpSmt3 deletion mutant exhibited an increase in mitochondrial ROS, swollen mitochondria, excess autophagy, and thickened cell walls. About 500 putative SUMO substrate proteins were identified by affinity pull-down, among which many were implicated in the cell cycle, ribosome, translation, and virulence. Proteomics and SUMO substrate analyses further revealed that deletion of CpSmt3 reduced the accumulation of CpRho1, an important protein that is involved in TOR signal transduction. Silencing of CpRho1 resulted in a phenotype similar to that of ΔCpSmt3, while overexpression of CpRho1 could partly rescue some of the prominent defects in ΔCpSmt3. Together, these findings demonstrate that SUMOylation by CpSmt3 is vitally important and provide new insights into the SUMOylation-related regulatory mechanisms in C. parasitica.

Hydrogen Transportation Behaviour of V-Ni Solid Solution: A First-Principles Investigation.

Hydrogen embrittlement causes deterioration of materials used in metal-hydrogen systems. Alloying is a good option for overcoming this issue. In the present work, first-principles calculations were performed to systematically study the effects of adding Ni on the stability, dissolution, trapping, and diffusion behaviour of interstitial/vacancy H atoms of pure V. The results of lattice dynamics and solution energy analyses showed that the V-Ni solid solutions are dynamically and thermodynamically stable, and adding Ni to pure V can reduce the structural stability of various VHx phases and enhance their resistance to H embrittlement. H atoms preferentially occupy the characteristic tetrahedral interstitial site (TIS) and the octahedral interstitial site (OIS), which are composed by different metal atoms, and rapidly diffuse along both the energetically favourable TIS → TIS and OIS → OIS paths. The trapping energy of monovacancy H atoms revealed that Ni addition could help minimise the H trapping ability of the vacancies and suppress the retention of H in V. Monovacancy defects block the diffusion of H atoms more than the interstitials, as determined from the calculated H-diffusion barrier energy data, whereas Ni doping contributes negligibly toward improving the H-diffusion coefficient.

Assessment of the risks from dietary lead exposure in China.

The dietary lead (Pb) risk across China was assessed based on the margin of exposure (MOE) approach by comparing the level (1.5 µg/kg/d) based on the Pb concentrations in foodstuffs from1386 published articles. The Pb averages of the 18 foods were lower than their corresponding limits enacted by the Chinese government, ranging from 0.09 to 0.30 mg/kg. Food from plants had a much higher contribution to dietary Pb intake than that from animals (86% vs. 14%), and cereals and vegetables contributed 79% of the Pb intake from plant-based food. Although each category of food contained a relatively low Pb concentration, the accumulated Pb from the total diet posed a high risk to human health. The MOE risk from dietary Pb averaged 1.57 and ranged from 0.13 to 6.18, with high risks in southern, southwestern, eastern, central, and northern China. The MOE risk from Pb could be decreased by adjusting the dietary structure, and the ratio of people categorized as high risk (MOE < 1) would decrease from 56% to 37%, 41%, or 24% if the category of cereal or vegetable or both cereals and vegetables with the lowest Pb concentration in their local areas were selected, respectively.

Investigation of adsorption, dissociation, and diffusion properties of hydrogen on the V (1 0 0) surface and in the bulk: A first-principles calculation.

To investigate the H2 purification mechanism of V membranes, we studied the adsorption, dissociation, and diffusion properties of H in V, an attractive candidate for H2 separation materials. Our results revealed that the most stable site on the V (1 0 0) surface is the hollow site (HS) for both adsorbed H atoms and molecules. As the coverage range increases, the adsorption energy of H2 molecules first decreases and then increases, while that of H atoms remains unchanged. The preferred diffusion path of atoms on the surface, surface to first subsurface, and first subsurface to second subsurface is HS → bridge site (BS) → HS, BS → BS, and BS → tetrahedral interstitial site (TIS) → BS, respectively. In the V bulk, H atoms occupy the energetically favourable TIS, and diffuse along the TIS → TIS path, which has a lower energy barrier. This study facilitates the understanding of the interaction between H and metals and the design of novel V-based alloy membranes.