Dimethyl sulfate (DMS) is a drug widely used as a pharmaceutical and synthetic raw material. On the other hand, it is highly toxic and requires management and treatment as a hazardous substance. A mass outbreak of chemical burns resulting from DMS poisoning occurred at a drug factory. All three patients were brought to our hospital, a tertiary emergency medical facility, several hours after exposure. Their vital signs were stable, with only eye pain and a sore throat. However, after admission, two patients required emergency tracheostomy or endotracheal intubation due to laryngeal edema. Improvement was achieved through the administration of steroids, but a severely injured patient required an extended treatment period. DMS poisoning is rare; however, it can be fatal depending on the exposure concentration. Furthermore, even if the initial symptoms are mild, laryngeal edema may develop later, requiring careful monitoring and appropriate airway interventions.

The curved π-conjugated surface of bowl-shaped corannulene has been multiply methylated to form exo-di-, -tetra-, and -hexamethylated corannulenes. The multimethylations became possible through in-situ iterative reduction/methylation sequences that involve the reduction of corannulenes using sodium to form the anionic corannulene species, and the subsequent SN 2 reaction of the anionic species with reduction-resistant dimethyl sulfate. X-ray diffraction analyses, NMR, MS, UV-Vis measurements, and DFT calculations have revealed the molecular structures of the multimethylated corannulenes and the sequence of the multimethylation. This work has the potential to contribute to the controlled synthesis and characterizations of multifunctionalized fullerenes.

Dimethyl sulfate is an important chemical raw material that is widely used in the synthesis of drugs, dyes, spices, and pesticides. The highly toxic and corrosive dimethyl sulfate residue in medicines is harmful to the human body, and hence, the residue level should be strictly controlled. Traditional detection methods use high-purity acetonitrile and anhydrous as the solvents, which limits the choice of detection solvents and degrades the versatility and accuracy of detection. Therefore, a simple and accurate method for the determination of dimethyl sulfate residues is urgently needed. Dimethyl sulfate is usually detected by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) with pyridine as the methylation substrate. In this study, a new method for the detection of dimethyl sulfate was established using tertiary amines such as aminophenazone, which has many advantages over pyridine, as the methylation substrate. For example, the hybrid orbital and electron cloud of the N atom are different, resulting in stronger nucleophilicity of aminophenazone. High temperatures that are detrimental to the stability of dimethyl sulfate are not required when using aminophenazone, and the aliphatic quaternary ammonium salt product is more stable, with good stability, low interference, good ionization properties, and high response. The separation was performed on a Waters Atlantis HILIC C18 column (100 mm×2.1 mm, 3.0 μm) using a mobile phase consisting of 10 mmol/L ammonium acetate solution-0.1% formic acid methanol solution (50∶50, v/v) at a flow rate of 0.3 mL/min. The column temperature was set at 40 ℃, and the sample size was 1 μL. Dimethyl sulfate was determined in the electrospray positive ionization (ESI+) and multiple reaction monitoring (MRM) modes. Dimethyl sulfate showed good linear relationships within the range of 0.9935 to 7.9480 ng/mL (r=0.9997). The limit of detection and limit of quantification for dimethyl sulfate were 0.50 ng/mL and 1.15 ng/mL, respectively. The recoveries (n=3)of dimethyl sulfate were 94.9% to 106.4%. The relative standard deviations (RSDs) were 1.44% to 5.51%. The RSD of the methylated aminophenazone peak area was 4.32%, indicating good stability of the reaction product. Dimethyl sulfate genotoxic impurities were not detected in 9 batches of aminophenazone, caffeine, and tegafur samples, which indicated that the drug manufacturers paid attention to the control of these impurities. The proposed method is advantageous over the existing techniques in terms of the better ion peak shape and higher molecular weight, without interference from other fragments. The method is specific, sensitive, simple, rapid, and accurate, and it can be used for the determination of dimethyl sulfate genotoxic impurities in aminophenazone and other medicines.

This paper analyzed the clinical data of 17 patients with inhalation dimethyl sulfate poisoning in Changzhou Third People\'s Hospital, in order to understand the clinical characteristics, treatment and prognosis of patients with inhalation dimethyl sulfate poisoning, and guide clinicians to make effective measures in time. Dimethyl sulfate poisoning progresses rapidly and dangerously. The prognosis is usually better if the patients are separated from the toxic environment as soon as possible, given glucocorticoids in early and short-term, closely observed respiratory tract injury, and treated with endotracheal intubation and invasive mechanical ventilation when necessary.
本文对常州市第三人民医院收治的17例吸入硫酸二甲酯中毒患者临床资料进行分析，为了解吸入硫酸二甲酯中毒患者的临床特征、治疗及预后，指导临床医生针对病情及时做出有效措施。硫酸二甲酯中毒病情进展快且凶险，尽早脱离有毒环境，早期、短程使用糖皮质激素，严密观察呼吸道损伤，必要时及时行气管插管有创机械通气治疗，预后通常较好。.

RNA structure is critically important to RNA viruses in every part of the replication cycle. RNA structure is also utilized by DNA viruses in order to regulate gene expression and interact with host factors. Advances in next-generation sequencing have greatly enhanced the utility of chemical probing in order to analyze RNA structure. This review will cover some recent viral RNA structural studies using chemical probing and next-generation sequencing as well as the advantages of dimethyl sulfate (DMS)-mutational profiling and sequencing (MaPseq). DMS-MaPseq is a robust assay that can easily modify RNA in vitro, in cell and in virion. A detailed protocol for whole-genome DMS-MaPseq from cells transfected with HIV-1 and the structure of TAR as determined by DMS-MaPseq is presented. DMS-MaPseq has the ability to answer a variety of integral questions about viral RNA, including how they change in different environments and when interacting with different host factors.

Transcripts have intrinsic propensity to form stable secondary structure that is fundamental to regulate RNA transcription, splicing, translation, RNA localization and turnover. Numerous methods that integrate chemical reactions with next-generation sequencing (NGS) have been applied to study in vivo RNA structure, providing new insights into RNA biology. Dimethyl sulfate (DMS) probing coupled with mutational profiling through NGS (DMS-MaPseq) is a newly developed method for revealing genome-wide or target-specific RNA structure. Herein, we present our experimental protocol of a modified DMS-MaPseq method for plant materials. The DMS treatment condition was optimized, and library preparation procedures were simplified. We also provided custom scripts for bioinformatic analysis of genome-wide DMS-MaPseq data. Bioinformatic results showed that our method could generate high-quality and reproducible data. Further, we assessed sequencing depth and coverage for genome-wide RNA structure profiling in Arabidopsis, and provided two examples of in vivo structure of mobile RNAs. We hope that our modified DMS-MaPseq method will serve as a powerful tool for analyzing in vivo RNA structurome in plants.

Among different RNA modifications, the helix 69 (H69) region of the bacterial ribosomal RNA (rRNA) contains three pseudouridines (Ψs). H69 is functionally important due to its location in the heart of the ribosome. Several structural and functional studies have shown the importance of Ψ modifications in influencing the H69 conformation as well as maintaining key interactions in the ribosome during protein synthesis. Therefore, a need exists to understand the influence of modified nucleosides on conformational dynamics of the ribosome under solution conditions that mimic the cellular environment. In this review on chemical probing, we provide detailed protocols for the use of dimethyl sulfate (DMS) to examine H69 conformational states and the influence of Ψ modifications under varying solution conditions in the context of both ribosomal subunits and full ribosomes. The use of DMS footprinting to study the binding of aminoglycosides to the H69 region of bacterial rRNA as a potential antibiotic target will also be discussed. As highlighted in this work, DMS probing and footprinting are versatile techniques that can be used to gain important insight into RNA local structure and RNA-ligand interactions, respectively.

Mutational profiling (MaP) enables detection of sites of chemical modification in RNA as sequence changes during reverse transcription (RT), subsequently read out by massively parallel sequencing. We introduce ShapeMapper 2, which integrates careful handling of all classes of adduct-induced sequence changes, sequence variant correction, basecall quality filters, and quality-control warnings to now identify RNA adduct sites as accurately as achieved by careful manual analysis of electrophoresis data, the prior highest-accuracy standard. MaP and ShapeMapper 2 provide a robust, experimentally concise, and accurate approach for reading out nucleic acid chemical probing experiments.

Objective: To establish a method to detect the concentrations of dimethyl sulfate in the air of workplace by GC-MS. Methods: DMS in the air of workplace adsorpted by Silicone tube, then desorped by acetone, add 1.0 ml of acetone, shake 1 min, placed after 30 min, the desorption solution qualitative and quantitative determination by gas chromatography-mass. Results: The calibration curves were liner in the range of 0.1-200.0 μg/ml. The within-run and between-run precisions were 2.6%-4.7% and 4.0%-9.0% respectively. The method detection limit is 0.1 μg/ml, the minimum detectable concentration is 0.02 mg/m(3) (in terms of sampling 4.5 L) . Add 1 ml of desorption liquid, place 30 min, the average desorption efficiency of more than 90%. Conclusion: This method has simple pretreatment, short analysis period, and optimized linear rage and limit of detection, and is suitable for the determination of DMS in workplace air.
目的： 建立工作场所空气中硫酸二甲酯（DMS）的气质联用（GC-MS）仪测定方法。 方法： 工作场所空气中的DMS经硅胶管吸附，硅胶倒入解吸瓶后，加入1.0 ml丙酮，振摇1 min，放置30 min后，解吸液由GC-MS仪进行定性和定量测定。 结果： 该方法的线性范围为0.1~200.0 μg/ml，方程为y=11 810x-4 943（r=0.999）；批内精密度为2.6%~4.7%，批间精密度为4.0%~9.0%；方法检出限为0.1 μg/ml，最低检出浓度为0.02 mg/m(3)（以采样4.5 L计）；平均解吸效率均大于90%。 结论： 该方法前处理简单，分析周期短，优化了线性范围、检测限等指标，适用于工作场所空气中DMS的测定。.

Photosystem II is the first of two light-driven oxidoreductase complexes in oxygenic photosynthesis. The biogenesis of photosystem II requires the synthesis of polypeptide subunits encoded by the genomes in the chloroplast and the nucleus. In the chloroplast of the green alga Chlamydomonas reinhardtii, the synthesis of each subunit requires interactions between the 5\' UTR of the mRNA encoding it and gene-specific translation factors. Here, we analyze the sequences and structures in the 5\' UTR of the psbC mRNA, which are known to be required to promote translation and genetic interaction with TBC1, a nuclear gene required specifically for psbC translation. Results of enzymatic probing in vitro and chemical probing in vivo and in vitro support three secondary structures and reveal that one participates in a pseudoknot structure. Analyses of the effects of mutations affecting pseudoknot sequences, by structural mapping and thermal gradient gel electrophoresis, reveal that flexibility at the base of the major stem-loop is required for translation and higher order RNA conformation, and suggest that this conformation is stabilized by TBC1. This RNA pseudoknot tertiary structure is analogous to the internal ribosome entry sites that promote translation of certain viruses and cellular mRNAs in the nuclear-cytoplasmic systems of eukaryotes.