Biosynthesis and Degradation of Sulfur Modifications in tRNAs

Various sulfur-containing biomolecules include iron–sulfur clusters that act as cofactors for enzymes, sulfur-containing vitamins such as thiamin, and sulfur-modified nucleosides in RNA, in addition to methionine and cysteine in proteins. Sulfur-containing nucleosides are post-transcriptionally introduced into tRNA molecules, where they ensure precise codon recognition or stabilization of tRNA structure, thereby maintaining cellular proteome integrity. Modulating sulfur modification controls the translation efficiency of specific groups of genes, allowing organisms to adapt to specific environments. The biosynthesis of tRNA sulfur nucleosides involves elaborate ‘sulfur trafficking systems’ within cellular sulfur metabolism and ‘modification enzymes’ that incorporate sulfur atoms into tRNA. This review provides an up-to-date overview of advances in our knowledge of the mechanisms involved. It covers the functions, biosynthesis, and biodegradation of sulfur-containing nucleosides as well as the reaction mechanisms of biosynthetic enzymes catalyzed by the iron–sulfur clusters, and identification of enzymes involved in the de-modification of sulfur atoms of RNA. The mechanistic similarity of these opposite reactions is discussed. Mutations in genes related to these pathways can cause human diseases (e.g., cancer, diabetes, and mitochondrial diseases), emphasizing the importance of these pathways.

INFLUENCE OF SULFUR MODIFICATION ON THE PROPERTIES OF SULFUR CONCRETE

The purpose of this study is the synthesis and study of modified sulfur concrete for use in industrial construction. To achieve this goal, sulfur concrete based on gossypol resin and pyrolysis distillate was modified and studied. The strength properties of sulfur-based concrete obtained from sulfur modified with gossypol resin and pyrolysis distillate were investigated. For the addition to sulfur concrete, industrial waste was used as a finely dispersed filler - fly ash from the Angren TPP and phosphogypsum generated at Ammophos-Maxam JSC. It was found that the best strength results correspond to sulfur-based concrete modified with gossypol resin using an additive in the form of phosphogypsum. The prototype characterized by low water absorption, high frost resistance in an aggressive environment (3% NaCl solution).

CARTECH 303

CarTech 303 is a free-machining austenitic stainless steel. The addition of sulfur to this 18-8 chromium-nickel austenitic stainless steel, which is ordinarily tough and difficult to machine, enhances the alloy’s machinability to the degree that it can be readily utilized for producing parts on automatic screw machines at about 70% of the speed of SAE 1212. This sulfur modification has led to widespread acceptance and use of this grade in the screw machine industry. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-1337. Producer or source: Carpenter Technology Corporation.

Sulfur Modification in Natural RNA and Therapeutic Oligonucleotides

Sulfur modifications have been discovered on both DNA and RNA. Sulfur substitution of oxygen atoms at nucleobase or backbone locations in the nucleic acid framework led to a wide variety...

X-ray diffraction and SEM analysis of waste sulfur modification for use in concretes

Secondary sulfur obtained as a by-product in the oil refining process is a major problem as an environmental pollutant. One of the possibilities of environmental protection is the use of sulfur obtained in this way as a component of sulfur concrete. Mixing of sulfur with suitable additives can provide longer working lifetime of sulfur concrete, as well as maintenance of the former physical, chemical, and mechanical properties of concrete. Such mixtures are usually called modified sulfur or sulfur cement. Secondary sulfur produced in the oil refining process by the Klaus process (approval of crude oil) cannot be used in this form. In order to be ready for the use of sulfur concrete and asphalt, it is necessary to modify elemental sulfur from cyclic to chain form, obtaining of modified sulfur whose application is as a binding agent in a concrete instead of portland cement is described in this paper. Influence of dicyclopentadien, an organic additive, on sulfur modification has been studied in this research. Microstructure and mineral analysis of modified and unmodified sulfur cement binding are performed using polarized and scanning electron microscopes and X-ray diffraction spectrometer.

Enhanced Pseudo-Capacitive Contributions to High-Performance Sodium Storage in TiO2/C Nanofibers via Double Effects of Sulfur Modification

Pseudo-capacitive mechanisms can provide higher energy densities than electrical double-layer capacitors while being faster than bulk storage mechanisms. Usually, they suffer from low intrinsic electronic and ion conductivities of the active materials. Here, taking advantage of the combination of TiS2 decoration, sulfur doping, and a nanometer-sized structure, as-spun TiO2/C nanofiber composites are developed that enable rapid transport of sodium ions and electrons, and exhibit enhanced pseudo-capacitively dominated capacities. At a scan rate of 0.5 mV s−1, a high pseudo-capacitive contribution (76% of the total storage) is obtained for the S-doped TiS2/TiO2/C electrode (termed as TiS2/S-TiO2/C). Such enhanced pseudo-capacitive activity allows rapid chemical kinetics and significantly improves the high-rate sodium storage performance of TiO2. The TiS2/S-TiO2/C composite electrode delivers a high capacity of 114 mAh g−1 at a current density of 5000 mA g−1. The capacity maintains at high level (161 mAh g−1) even after 1500 cycles and is still characterized by 58 mAh g−1 at the extreme condition of 10,000 mA g−1 after 10,000 cycles.

A mesoporous Au film with surface sulfur modification for efficient ammonia electrosynthesis

We report a two-step strategy for synthesizing a sulfur-decorated mesoporous film on Ni foam towards an efficient electrosynthesis of ammonia.

tRNA Wobble Modification Affects Leaf Cell Development in Arabidopsis thaliana

The tRNA modification at the wobble position of Lys, Glu and Gln (wobbleU* modification) is responsible for the fine-tuning of protein translation efficiency and translation rate. This modification influences organism function in accordance with growth and environmental changes. However, the effects of wobbleU* modification at the cellular, tissue, or individual level have not yet been elucidated. In this study, we show that sulfur modification of wobbleU* of the tRNAs affects leaf development in Arabidopsis thaliana. The sulfur modification was impaired in the two wobbleU*-modification mutants: the URM1-like protein-defective mutant and the Elongator complex-defective mutants. Analyses of the mutant phenotypes revealed that the deficiency in the wobbleU* modification increased the airspaces in the leaves and the leaf size without affecting the number and the area of palisade mesophyll cells. On the other hand, both mutants exhibited increased number of leaf epidermal pavement cells but with reduced cell size. The deficiency in the wobbleU* modification also delayed the initiation of the endoreduplication processes of mesophyll cells. The phenotype of ASYMMETRIC LEAVES2-defective mutant was enhanced in the Elongator-defective mutants, while it was unchanged in the URM1-like protein-defective mutant. Collectively, the findings of this study suggest that the tRNA wobbleU* modification plays an important role in leaf morphogenesis by balancing the development between epidermal and mesophyll tissues.