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Fibroin has been extensively applied in the medicine, therapy, cosmetic, and food fields. Functional modification is a common route way to expand the application potential. Tyrosinase is versatile for enzymatic functionalization of fibroin by oxidizing tyrosine residues into dopaquinone. However, grafting of functional molecules to the protein-bound dopaquinone suffers from self-crosslinking due to competitive aryl coupling or addition with other nucleophile in protein. Herein, bioinspired from pheomelanin synthesis, a new approach with superior grafting efficiency and reaction rate for enzymatic grafting of protein was developed. The high reactivity of Michael addition between thiol and dopaquinone was utilized to promote the efficiency for grafting of PEG onto fibroin. The grafting of PEG with thiol group was superior to that with amine group. It demonstrated a superior efficacy for thiol group over amino group on enzymatic functionalization. This research firstly established an effective biomimetic approach for enzymatic functionalization of protein without the unexpected self-crosslinking. It could emerged to serve as the strategy of protein functionalization. [Display omitted] • Bioinspiration from pheomelanin due to preference over eumelanin. • Strong competition against self-crosslinking. • Higher reactivity of thiols to dopaquinone than amines. • Superior grafting efficiency and reaction rate. • Versatile application extended to functionalization of protein. [ABSTRACT FROM AUTHOR]

The cysteine and alkanethiol adsorption on Au(111) surfaces is investigated using density functional theory (DFT) and classic molecular dynamics (MD). Understanding the S–Au interaction across different scales poses major challenges. DFT provides atomic‐level precision but it hardly provides insight on nanosecond scale dynamics of this interface. Alternatively, MD, although it enables modeling larger systems for longer periods, its accuracy heavily relies on the parameterization of the force fields (FF). To address this, an MD potential is fitted using DFT calculations, bridging the gap in accuracy and efficiency. At the DFT level, it is found that PBE with DFT‐D3 reproduces complex approaches at a fraction of the computational cost. Separating PBE and DFT‐D3 contributions reveals consistent PBE energy across molecules (chemisorption), while dispersion varies (physisorption). Thus, the interaction energy of cysteine and two short‐chain alkanethiols is calculated to parameterize both Morse and Lennard–Jones (LJ) potentials. The parameterization improves the potential energy in the preferred adsorption sites: the threefold hcp and fcc with respect to the previous proposals in the literature. Furthermore, the transferability is here demonstrated. At last, these results show that LJ potentials outperform more complex Morse potentials. The procedure is general, and the codes and supporting inputs are publicly available, allowing swift generation of potential energy surfaces (PES) at the DFT level, and fitted LJ or Morse potentials to any molecular interface. [ABSTRACT FROM AUTHOR]

A visible‐light‐promoted reduction of nitrobenzenes using formate salts as the reductant was developed. A wide range of nitrobenzenes can be converted into aniline products in a transition metal free fashion. Mechanistic studies revealed that radical species (carbon dioxide radical anion and thiol radical) are key intermediates for the transformation. We anticipate that this method will provide a valuable and green strategy for the reduction of nitrobenzenes. [ABSTRACT FROM AUTHOR]

Cys is one of the least abundant amino acids in proteins. However, it is often highly conserved and is usually found in important structural and functional regions of proteins. Its unique chemical properties allow it to undergo several post-translational modifications, many of which are mediated by reactive oxygen, nitrogen, sulfur, or carbonyl species. Thus, in addition to their role in catalysis, protein stability, and metal binding, Cys residues are crucial for the redox regulation of metabolism and signal transduction. In this review, we discuss Cys post-translational modifications (PTMs) and their role in plant metabolism and signal transduction. These modifications include the oxidation of the thiol group (S-sulfenylation, S-sulfinylation and S-sulfonylation), the formation of disulfide bridges, S-glutathionylation, persulfidation, S-cyanylation S-nitrosation, S-carbonylation, S-acylation, prenylation, CoAlation, and the formation of thiohemiacetal. For each of these PTMs, we discuss the origin of the modifier, the mechanisms involved in PTM, and their reversibility. Examples of the involvement of Cys PTMs in the modulation of protein structure, function, stability, and localization are presented to highlight their importance in the regulation of plant metabolic and signaling pathways. [ABSTRACT FROM AUTHOR]

[Display omitted] Disulfide bonds, especially unsymmetric disulfide bonds, have important applications in bioactivity and drug molecules, but the synthesis of unsymmetric disulfide bonds remains challenging due to efficiency and selectivity issues. Herein, this work utilizes anthraquinone (AQ) and cyclictriphosphonononitrile through a nucleophilic substitution reaction to synthesize an organic polymer (ANTH-AMI) that incorporates an ortho -polyquinone (o -polyquinone) redox center. The anthraquinone molecule functions as a redox center, capable of accepting photoinduced electrons and subsequently transferring them to initiate an electron-coupled hydrogenation reaction (AQ to AQH). Moreover, the proximity of the o -polyquinone redox sites facilitates the catalysis of unsymmetric disulfide bond formation. Consequently, the ANTH-AMI photocatalysts demonstrate exceptional yields (up to 82 %), substrate versatility, cycling stability, and scalable preparation in promoting unsymmetric coupling reactions of thiol. This work offers a solution for designing organic polymer photocatalysts with adjacent multiple redox centers for cross-coupling reactions. [ABSTRACT FROM AUTHOR]

Diketopyrrolopyrroles (DPPs) are a versatile group of dyes and pigments with valuable optoelectronic properties. In this work we report the synthesis of highly fluorescent DPP derivatives through straightforward nucleophilic aromatic substitution reactions with thiols and phenols. These nucleophilic substitutions occur at room temperature and manifest a remarkable selectivity for the 4-position of the pentafluorophenyl groups. Both symmetrical (disubstitution) and non-symmetrical (monosubstitution) DPP derivatives are formed in excellent overall yields. The optical properties of the newly synthesized compounds are also discussed. The new platform may be useful for bioorthogonal chemistry.

AbstractLocalized oral drug delivery offers several advantages for treating various disease conditions. However, drug retention at the disease site within the oral cavity is indeed a significant challenge due to the dynamic oral environment. The present study aimed to develop a mucoadhesive inner layer for a three-layer mucoadhesive bandage suitable for localized oral drug delivery. using gellan gum (GG) biopolymer. Gellan gum (GG) was modified using L-cysteine moieties via carbodiimide chemistry. Subsequently, gellan gum solution at different extents of thiolation was ionically cross-linked using aluminum ammonium sulfate. Thiolated gellan gum films of uniform thickness were prepared using a solvent casting method. The thickness of bare gellan gum film was 0.035 ± 0.0043 mm, whereas the thiolated gellan gum films, GG 1S and GG 2S showed a thickness of 0.0191 ± 0.0011 mm and 0.0188 ± 0.0004 mm respectively. A high work of adhesion was noted for thiolated gellan gum (GG 2S) with a value of 10 N.mm while using porcine buccal mucosa. An average tensile strength of 48.2 ± 2.46 MPa was measured for thiolated gellan gum films irrespective of the extent of thiolation. The high work of adhesion, favorable cytocompatibility, desirable mechanical properties, and free swell capacity in saline confirmed the suitability of ionically cross-linked thiolated gellan gum films as an inner mucoadhesive layer for the mucoadhesive bandage. [ABSTRACT FROM AUTHOR]

Aim: Laparoscopic cholecystectomy is one of the treatment methods employed in symptomatic cholelithiasis cases, and pneumoperitoneum has been shown to increase oxidative stress. Our aim is to compare propofol and thiopental in terms of their effects on oxidative stress parameters in laparoscopic cholecystectomy cases. Materials and Methods: After obtaining Ethics Committee permission, patients who underwent laparoscopic cholecystectomy were divided into thiopental and propofol groups according to the agent used for anesthesia induction in the randomized and prospective study. Serum oxidative stress parameters levels were measured in all patients twice before induction of general anesthesia and at the 30th minute postoperatively. Results: When comparing the preoperative period with the postoperative period, total antioxidant status (TAS) levels increased statistically significantly in the propofol group (preoperatively 1.21±0.21 mmolH2O2/L, postoperatively 1.31±0.18 mmolH2O2/L, p<0.001) compared to the thiopental group (preoperatively 1.23±0.14 mmolH2O2/L, postoperatively 1.27±0.14 mmolH2O2/L, p=0.055). arylesterase (ARES), serum native thiol, total thiol, and disulfide levels decreased statistically significantly in both groups. While Paraoxonase-1 (PON1) level did not change in the propofol group, it decreased in the thiopental group. Conclusion: We concluded that propofol had a significantly greater oxidative stress reduction effect than thiopental. By increasing the TAS levels, propofol may have a more positive effect on oxidative stress than thiopental. However, neither propofol nor thiopental have oxidative stressreducing effects on other oxidative stress parameters. [ABSTRACT FROM AUTHOR]

Many studies show either the absence, or very low levels of, SARS-CoV-2 viral RNA and/or antigen in the brain of COVID-19 patients. Reports consistently indicate an abortive infection phenomenon in nervous cells despite the fact that they contain the SARS-CoV-2 receptor, ACE2. Dopamine levels in different brain regions are in the range of micromolar to millimolar concentrations. We have shown that sub-micromolar to low micromolar concentrations of dopamine or its precursor (levodopa) time- and dose-dependently inhibit the activity of SARS-CoV-2 main protease (Mpro), which is vital for the viral life cycle, by forming a quinoprotein. Thiol detection coupled with the assessment of Mpro activity suggests that among the 12 cysteinyl thiols, the active site, Cys145-SH, is preferentially conjugated to the quinone derived from the oxidation of dopamine or levodopa. LC-MS/MS analyses show that the Cys145-SH is covalently conjugated by dopamine- or levodopa- o -quinone. These findings help explain why SARS-CoV-2 causes inefficient replication in many nerve cell lines. It is well recognized that inhaled pulmonary drug delivery is the most robust therapy pathway for lung diseases. CVT-301 (orally inhaled levodopa) was approved by the FDA as a drug for Parkinson's patients prior to the outbreak of COVID-19 in 2018. Based on the fact that SARS-CoV-2 causes inefficient replication in the CNS with abundant endogenous Mpro inhibitor in addition to the current finding that levodopa has an Mpro-inhibitory effect somewhat stronger than dopamine, we should urgently investigate the use of CVT-301 as a lung-targeting, COVID-19, Mpro inhibitor. [Display omitted] • The reason SARS-CoV-2 fails to cause productive infection in many nerve cell lines is unclear. • Neurons are rich in dopamine which inhibits Mpro by forming a quinoprotein. • Dopamine- o -quinone preferentially reacts with the active site, Cys145-SH, of 12 Mpro cysteinyl thiols. • The dopamine precursor, levodopa, exhibits an inhibitory effect stronger than that of dopamine itself. • Orally inhaled levodopa (the FDA-approved CVT-301) could be repurposed as an Mpro-inhibitor of COVID-19 that targets the lung. [ABSTRACT FROM AUTHOR]

Resveratrol (3,5,4′-trihydroxy-trans-stilbene), a phenol commonly found in grapes and wine, has been associated as protective in experimental models involving alterations in different neurotransmitter systems. However, studies are reporting that resveratrol could have adverse effects. This study evaluated if the association of a low dose of ketamine and resveratrol could induce behavioral manifestations associated with biochemical alterations. Moreover, the effects of treatment with resveratrol and/or ketamine on monoamine oxidase (MAO) activity, oxidative stress markers, and IL-6 levels in the brain were also investigated. Male Swiss mice received a low dose of ketamine (20 mg/kg) for 14 consecutive days, and resveratrol (10, 30, or 100 mg/kg) from day 8 up to day 14 of the experimental period, intraperitoneally. Locomotor, stereotyped behavior, Y-maze, novel recognition object test (NORT), and social interaction were quantified as well as ex vivo analysis of MAO activity, IL-6 levels, and oxidative stress markers (TBARS and total thiol levels) in brain tissues. Ketamine per se reduced the number of bouts of stereotyped behavior on day 8 of the experimental period. Resveratrol per se reduced the locomotor and exploratory activity in the open field, the time of exploration of new objects in the NORT, MAO-A activity in the striatum and increased the IL-6 levels in the cortex. These effects were attenuated when the mice were co-treated with ketamine and resveratrol. There was a decrease in MAO-A activity in the cortex of mice treated with ketamine + resveratrol 100 mg/kg. No significant alterations were found in oxidative stress markers. Resveratrol does not appear to cause summative effects with ketamine on behavioral alterations. However, the effect of resveratrol per se, mainly on locomotor and exploratory activity, should be better investigated. [ABSTRACT FROM AUTHOR]

The incorporation of antioxidants in food products is essential to prevent or delay deterioration, thereby addressing food spoilage. Thiol compounds, recognized for their natural antioxidant properties, are widely used in various foods; however, their antioxidant capacity is often limited. This study investigates the potential enhancement of thiol antioxidant capacity through the addition of a soluble, low-toxic inorganic Sm-cluster. Our findings demonstrate that the Sm-cluster significantly bolsters the antioxidant efficacy of thiol compounds. We explored, for the first time, the in vitro antioxidant activities of an Sm-oxo/hydroxy cluster combined with a cysteine derivative for potential food applications. The composition exhibited a robust inhibition of aromatic aldehyde flavor compound oxidation and displayed strong, dose-dependent DPPH (2,2-diphenyl-1-picrylhydrazine) radical scavenging activity. Notably, the antioxidant activity of the Sm-cluster/cysteine derivative was further enhanced under strong visible light conditions, which typically increased the likelihood of oxidation. These results suggest that the combination of inorganic cluster and thiol compounds presents a promising natural alternative to traditional antioxidants in the food industry. [ABSTRACT FROM AUTHOR]

Objective Methods Results Conclusion To compare the levels of oxidative stress markers in the umbilical cord blood between pregnant women diagnosed with iron deficiency anemia (IDA) and low‐risk controls.The sample consisted of 131 patients, including 55 pregnant women with IDA and 76 controls with similar demographic characteristics. Participants were selected from patients delivered at ≥37 weeks. We compared the two groups in terms of the native thiol, total thiol, disulfide, and ischemia‐modified albumin (IMA) levels measured in pregnant women's umbilical cord venous blood.The native thiol and total thiol values were statistically significantly lower in the anemia group, and the disulfide and IMA values were statistically significantly higher in the IDA group (P < 0.001). Perinatal outcomes were similar between the groups.In the present study, pregnant women with IDA had lower native and total thiol values and higher disulfide and IMA values in umbilical cord blood. Iron deficiency anemia in pregnancy may be a potential cause of increased oxidative stress. [ABSTRACT FROM AUTHOR]

The cascade reaction of ynamides with propargyl thiols by Au(I) catalysis involving regioselective hydrothiolation, thio‐Claisen rearrangement, and cycloisomerization to generate 2‐aminothiophenes in a one‐pot manner is described. In this reaction, the selection of reaction temperature is crucial, with the initial step, namely hydrothiolation, conducted at a low temperature (40 °C), followed by the subsequent reaction requiring an increase in temperature (>110 °C). Furthermore, it was revealed that multi‐substituted anilines could be synthesized from the resulting 2‐aminothiophenes. [ABSTRACT FROM AUTHOR]

Autism spectrum disorder (ASD) is a mosaic of neurodevelopmental conditions composed of early-onset social interaction and communication deficits, along with repetitive and/or restricted patterns of activities, behavior, and interests. ASD affects around 1% of children worldwide, with a male predominance. Energy, porphyrin, and neurotransmitter homeostasis are the key metabolic pathways affected by heavy metal exposure, potentially implicated in the pathogenesis of ASD. Exposure to heavy metals can lead to an altered porphyrin metabolism due to enzyme inhibition by heavy metals. Heavy metal exposure, inborn genetic susceptibility, and abnormal thiol and selenol metabolism may play a significant role in the urinary porphyrin profile anomalies observed in ASD. Altered porphyrin metabolism in ASD may also be associated with, vitamin B6 deficiency, hyperoxalemia, hyperhomocysteinemia, and hypomagnesemia. The present review considers the abnormal porphyrin metabolism in ASD in relation to the potential pathogenic mechanism and discusses the possible metabolic therapies such as vitamins, minerals, cofactors, and antioxidants that need to be explored in future research. Such targeted therapeutic therapies would bring about favorable outcomes such as improvements in core and co-occurring symptoms. [ABSTRACT FROM AUTHOR]

In this research, we explored the synthesis and application of thiolactone acrylamide (TLA) polymers for neutralizing reactive oxygen species (ROS), produced as a result of traumatic brain injury (TBI). We synthesized well‐defined TLA polymers using RAFT (reversible addition‐fragmentation chain transfer) polymerization across a range of monomer‐to‐chain transfer agent ([M]0/[CTA]0) ratios to achieve a range of molar masses. Polymerizations were carried out using a trithiocarbonate CTA (chain transfer agent) with AIBN (azobisisobutyronitrile) as the initiator in N'N‐dimethylacetamide (DMAc) at 60 °C. Kinetic studies indicated a linear increase in molar mass with conversion, pseudo‐first‐order kinetics, and molar mass values that are consistent with theoretical predictions. Furthermore, the polymerizations exhibited a decrease in molar mass dispersity with conversion. We then investigated ring opening of the thiolactone residues with isoserinol (ISOH), which was followed by thiol‐ene reactions of the resultant thiol groups with methacrylamide to yield a series of copolymers with different thiol‐to‐thioether ratios. The resulting polymers demonstrated varying levels of ROS neutralization. Higher thiol concentrations lead to more rapid neutralization while thioether residues provided sustained neutralization activity. [ABSTRACT FROM AUTHOR]

Control of the porous structure and particle size is essential for improving the properties of polysilsesquioxane (PSQ) microspheres. Herein, using the strategy combining inverse suspension polymerization, two-step sol–gel- and polymerization-induced phase separation processes, micron-sized thiol-containing macroporous PSQ (TMPSQ) microspheres with controllable morphologies, adjustable particle diameters (4.9–17.3 μm), and pore sizes (40–3774 nm) were prepared. The morphology and size of the TMPSQ microspheres were characterized by SEM. The mercury intrusion method was employed to analyze the porous structure of the microspheres. The effects of the composition of the sol–gel disperse phase, the mass ratio of the sol–gel disperse phase to the oil continuous phase (WRW/O), and the Span 80 mass content in the oil continuous phase on the morphology, particle diameter and pore size of the TMPSQ microspheres were investigated. Results indicated that the composition of the sol–gel disperse phase determines the morphology and porous structure of the microspheres, and WRW/O and Span 80 content have remarkable impacts on the morphology and particle size of the microspheres. This study is beneficial to the design and fabrication of functional PSQ microspheres with desired properties and promising application prospects. [ABSTRACT FROM AUTHOR]

Purpose: Chronic Obstructive Pulmonary Disease (COPD) is linked to increased oxidative stress. Changing oxidative stress status due to anesthesia applications may affect surgical stress and the incidence of postoperative complications. This study aims to contrast the impacts of general anesthesia (GA) and spinal anesthesia (SA) on the dynamic thiol-disulfide homeostasis among patients with COPD who are undergoing inguinal hernia surgery. Materials and Methods: According to the 2017 Global Strategy Report for the Diagnosis, Management and Prevention of COPD, patients with airflow obstruction (50%≤FEV1

The objective of this research was to explore the link between Helicobacter pylori (H. pylori) infection and alterations in ischemia modified albumin (IMA), thiol, and disulfide levels, with a focus on their potential clinical implications.

The bulky aryl thiol, MSFluindSH (1S), and aryl selenol, MSFluindSeH (1Se), possessing a tetramethyl‐s‐hydrindacen‐4'‐yl‐(Rind)‐based substituent containing two fluorenyl groups in 9 and 9'‐positions, were prepared (MSFluind=dispiro[fluorene‐9,3'‐(1',1',7',7'‐tetramethyl‐s‐hydrindacene‐4'‐yl)‐5',9"‐fluorene]). The reaction of 1S and 1Se with Et2Zn provided a monomeric zinc aryl thiolate, Zn(SMSFluind)2 (2S), and zinc aryl selenolate, Zn(SeMSFluind)2 (2Se), with essentially two‐coordinate zinc atoms. [ABSTRACT FROM AUTHOR]

A series of novel thio-derivatives of d-glucosamine has been synthesized using double inversion procedures at the C3 atom. New compounds were applied as ligands for the diethylzinc addition to benzaldehyde and the products of the addition were obtained with a low to good enantiomeric ratio. The direction and the level of the asymmetric induction were highly dependent on the type of protecting groups on the nitrogen and sulfur atoms. [ABSTRACT FROM AUTHOR]

Garlic is known to have diverse effects on mammalian cells, being cytotoxic, especially to cancer cells, but also protect against oxidative stress. Mammalian erythrocyte is a simple cell devoid of intracellular organelles, protein synthesis ability, and most signaling pathways. Therefore, examination of the effects of garlic on erythrocytes allows for revealing primary events in the cellular action of garlic extract. In this study, human erythrocytes or erythrocyte membranes were exposed to garlic extract at various dilutions. Hemoglobin oxidation to methemoglobin, increased binding of hemoglobin to the membrane, and formation of Heinz bodies were observed. Garlic extract depleted acid-soluble thiols, especially glutathione, and induced a prooxidative shift in the cellular glutathione redox potential. The extract increased the osmotic fragility of erythrocytes, induced hemolysis, and inhibited hemolysis in isotonic ammonium chloride, indicative of decreased membrane permeability for Cl− and increased the membrane fluidity. Fluorescent probes indicated an increased level of reactive oxygen species and induction of lipid peroxidation, but these results should be interpreted with care since the extract alone induced oxidation of the probes (dichlorodihydrofluorescein diacetate and BODIPY C11). These results demonstrate that garlic extract induces oxidative changes in the erythrocyte, first of all, thiol and hemoglobin oxidation. [ABSTRACT FROM AUTHOR]

The generation of thioesters through thioesterification of carboxylic acid has significant synthetic value given the easy availability of various carboxylic acids and the extensive application of thioesters. An economical and rapid thioester synthesis approach is still needed. Herein, we achieved thioesterification of carboxylic acids with valuable glycosyl thiol, aromatic and aliphatic thiols mediated by sulfonyl fluoride (SO2F2). The compatibility of numerous carboxylic acid substrates was tested, including (hetero)aromatic and aliphatic carboxylic acids and the reaction proceeded smoothly under mild conditions at good yields. Late‐stage modification of drug molecules rac‐Naproxen and Loxoprofen proved feasible. Besides, the gram‐scale reaction demonstrated the utility of this protocol. [ABSTRACT FROM AUTHOR]

Understanding and controlling the sintering behaviour of gold nanoparticles is important in the field of ligand-protected nanoparticles for their use as precursors for thin film fabrication. Lowering the temperature of the sintering event of gold nanoparticles by facilitating desorption of the ligand through oxidation can provide compatibility of sintered gold nanoparticle thin films onto heat-sensitive substrates. Here we examine the processes by which 1-butanethiol-protected gold nanoparticles sinter under an ozone-rich environment. Upon heating, an ozone-rich environment significantly reduces the temperature of the sintering event when compared to sintering under ambient conditions. At room temperature, exposure to an ozone-rich environment induces sintering over a period of 2.5 h. Upon exposure to ozone, the surface-bound butanethiol ligands are oxidised to 1-butanesulfonic acid which facilitates sintering. [ABSTRACT FROM AUTHOR]

The compositional scope of polymer zwitterions has grown significantly in recent years and now offers designer synthetic materials that are broadly applicable across numerous areas, including supracolloidal structures, electronic materials interfaces, and macromolecular therapeutics. Among recent developments in polymer zwitterion syntheses are those that allow insertion of reactive functionality directly into the zwitterionic moiety, yielding new monomer and polymer structures that hold potential for maximizing the impact of zwitterions on the macromolecular materials chemistry field. This manuscript describes the preparation of zwitterionic choline phosphate (CP) methacrylates containing either aromatic or aliphatic thiols embedded directly into the zwitterionic moiety. The polymerization of these functional CP methacrylates by reversible addition‐fragmentation chain‐transfer methodology yields polymeric zwitterionic thiols containing protected thiol functionality in the zwitterionic units. After polymerization, the protected thiols are liberated to yield thiol‐rich polymer zwitterions which serve as precursors to subsequent reactions that produce polymer networks as well as polymer‐protein bioconjugates. [ABSTRACT FROM AUTHOR]

Aim: We aim to compare the maternal serum thiol and ischemia‐modified albumin (IMA) levels between pregnant women with placenta previa and those with uncomplicated pregnancies and to determine whether changes in these levels were useful in predicting cases of abnormally invasive placenta (AIP). Methods: Fifty‐five pregnant women diagnosed with placenta previa according to the diagnostic criteria (case group) were compared to 100 women with uncomplicated pregnancies of similar demographic characteristics (control group). The patients with placenta previa were further divided into two subgroups: AIP (n = 20) and placenta previa without invasion (n = 35). The maternal serum native thiol, total thiol, disulfide, and IMA levels of the groups were evaluated. Results: The native thiol, total thiol, and IMA values were significantly lower in the case group than in the control group (p < 0.001). The disulfide values were similar between the study and control groups (p = 0.488). When the AIP and placenta previa without invasion groups were compared, the levels of native thiol, total thiol, disulfide, and IMA were similar (p > 0.05). Conclusions: Maternal serum thiol and IMA levels were lower in placenta previa cases compared to the control group. However, these parameters were not useful in predicting AIP cases. [ABSTRACT FROM AUTHOR]

Purpose: Due to the diverse biological activities attributed to its antioxidant, antidiabetic, anti-inflammatory, and cytoprotective properties, cyanidin-3-glucoside (Cy3G) has been widely studied. The present study was conducted to investigate the effects of Cy3G supplementation on redox balance disruption during acute exercise. Materials and Methods: To this end, 28 male Balb-C mice were divided into four groups: control, exercise, Cy3G, and exercise+Cy3G. During the experimental period, the mice in the Cy3G and exercise+Cy3G groups were administered 5 mg of Cy3G per kg of body weight, while the control and exercise groups were fed standard chow. The mice were trained on treadmill for 10 min every day at speed of 10 m/min for 2 weeks. On the 15th day, an acute exhaustion exercise was applied. Then, all groups were sacrificed, and serum samples were taken to analyze the native thiol, total thiol, disulfide, and thiol-disulfide indices. Results: The findings showed that the combination of Cy3G and exercise significantly increased native thiol levels and decreased disulfide levels compared to the other groups. However, it did not cause any change in total thiol levels. Native thiol were measured as 114.6±64.1, 106.4 ±57.9, 200.1±84.2, 262.1±105.9; Disulfide were determined as 253.2±71.6, 257.4±31.5, 213.8±44.8 and 188.4±32.2; Total thiol were 621.1±116.1, 621.2±100.1, 627.7±125.8 and 639.0±105.3 (respectively; control, exercise, Cy3G, and exercise+Cy3G). Conclusion: Cy3G supplementation can potentially maintain redox balance during acute exercise by supporting antioxidant defense systems and reducing oxidative stress. The use of Cy3G may have a positive effect on preventing exercise-induced oxidative stress and acute fatigue. [ABSTRACT FROM AUTHOR]

In the present study, it has been synthesized a new polymer, OXPESH (oxidized polyethylene functionalized with thiol groups), based on commercially used OXPE (oxidized polyethylene) for possible uses in the removal of heavy metals. Thiol-based oxidized polyethylene was successfully obtained by the esterification process. The synthesized polymeric material was employed as a possible adsorbent for the removal of heavy metal ions from aqueous solutions. Different techniques (1H-NMR, FTIR, ICP-MS, (Elemental Analysis), XPS, SEM–EDX, TGA/DTG) were used to characterize the physical and chemical properties of the obtained adsorbent. it was observed that the optimum pH values for the adsorption capacity and removal efficiency of heavy metal ions were 6–8. It was observed that the adsorbent removed the best Ag+ > Cr3 + > Pb2+ > Al3+ > Cd2+ > Ni2+ > Cu2+ from the aqueous solution. As a result, thiol–based oxidized polyethylene has been demonstrated to be an effective sorbent for the removal of heavy metal ions from aqueous solution, indicating its potential relation with water improvement. [ABSTRACT FROM AUTHOR]

Xenograft bone granules are bone graft materials that are widely used to reconstruct bone tissue in clinical practice, and their clinical success requires aggregation with a biocompatible binder. While the catechol mussel bioadhesive has been used as a key universal biomedical glue moiety, the thiols in mussel adhesive proteins have recently been shown to play key roles in mussel wet adhesion. Here, pentaerythritol tris(3-mercaptopropionate)-di-catechol (PETMP-di-catechol), a catechol- and thiol-containing binder molecule that mimics mussel adhesive proteins, was used to aggregate xenograft bone granules and reconstruct bone tissue. The PETMP-di-catechol-aggregated xenograft bone granules were most resistive to compression stress when both the catechol and thiol moieties in PETMP-di-catechol were chemically oxidized with sodium periodate. The xenograft bone granules aggregated with the oxidized PETMP-di-catechol exhibited enhanced osteogenic cellular behavior in vitro and in vivo in a rat calvarial defect model, compared to the control group treated with catechol-conjugated chitosan, a catechol-containing polymer binder devoid of thiol moieties. Hence, the thiol-containing catechol-functionalized binder exhibits improved bone tissue reconstruction properties by mimicking mussel wet adhesion. In addition, our study suggests that PETMP-di-catechol is a potential biocompatible bone binder for use in clinical settings. [ABSTRACT FROM AUTHOR]

Objective Multiple sclerosis (MS) is a chronic autoimmune disease in which neuroinflammation and oxidative stress play important roles in its pathology. Thioldisulphide homeostasis is considered a marker of oxidative stress and shown to be affected in several disorders including MS. The aim of this study was to compare salivary disulfide and thiol levels in MS patients with systemically healthy controls and to evaluate whether periodontal status had an effect on thiol-disulfide homeostasis in saliva. Material and Method This descriptive study included a total of 184 volunteers, 92 with MS and 92 systemically healthy volunteers. Each person underwent medical, neurological and oral examinations. In saliva samples, native thiol (NT), total thiol (TT), disulphide levels were measured. The ratios of NT/TT, disulphide/NT, D/TT were calculated and compared between the patient and control groups. Results There was not any difference in the periodontal parameters between the MS and healthy volunteers (p>0.05), however, the biomarkers of thiol-disulphide homeostasis in saliva were significantly different between the groups (p<0.002), except for TT. When grouped according to periodontal status, although salivary parameters did not differ in both the MS and control groups (p>0.05), MS patients showed decreased NT/TT and increased disulphide/NT ratios compared to the healthy volunteers (p<0.05). Conclusion Our results have shown that salivary thiol-disulphide balance was shifted to the oxidative side in MS patients. [ABSTRACT FROM AUTHOR]

Cysteine is one of the least abundant but most conserved amino acid residues in proteins, playing a role in their structure, metal binding, catalysis, and redox chemistry. Thiols present in cysteines can be modified by post-translational modifications like sulfenylation, acylation, or glutathionylation, regulating protein activity and function and serving as signals. Their modification depends on their position in the structure, surrounding amino acids, solvent accessibility, pH, etc. The most studied modifications are the redox modifications by reactive oxygen, nitrogen, and sulfur species, leading to reversible changes that serve as cell signals or irreversible changes indicating oxidative stress and cell damage. Selected antioxidants undergoing reversible oxidative modifications like peroxiredoxin-thioredoxin system are involved in a redox-relay signaling that can propagate to target proteins. Cysteine thiols can also be modified by acyl moieties' addition (derived from lipid metabolism), resulting in protein functional modification or changes in protein anchoring in the membrane. In this review, we update the current knowledge on cysteine modifications and their consequences in pancreatic β-cells. Because β-cells exhibit well-balanced redox homeostasis, the redox modifications of cysteines here serve primarily for signaling purposes. Similarly, lipid metabolism provides regulatory intermediates that have been shown to be necessary in addition to redox modifications for proper β-cell function and, in particular, for efficient insulin secretion. On the contrary, the excess of reactive oxygen, nitrogen, and sulfur species and the imbalance of lipids under pathological conditions cause irreversible changes and contribute to oxidative stress leading to cell failure and the development of type 2 diabetes. [ABSTRACT FROM AUTHOR]

Polysilsesquioxane (PSQ) microspheres have shown promise in many fields, but previous studies about porous PSQ microspheres are scarce. Herein, we fabricated novel micron-sized thiol-functional polysilsesquioxane (TMPSQ) microspheres with open and interconnected macropores by combining inverse suspension polymerization with two-step sol–gel and polymerization-induced phase separation processes, without using phase-separation-promoting additives or sacrificial templates. The chemical composition of the TMPSQ microspheres was confirmed using FTIR and Raman spectroscopy. The morphology of the TMPSQ microspheres was characterized using SEM and TEM. TGA was employed to test the thermal stability of the TMPSQ microspheres. Mercury intrusion porosimetry and nitrogen adsorption–desorption tests were performed to investigate the pore structure of the TMPSQ microspheres. The results showed that the TMPSQ microspheres had open and interconnected macropores with a pore size of 839 nm, and the total porosity and intraparticle porosity reached 70.54% and 43.21%, respectively. The mechanism of porous generation was proposed based on the morphological evolution observed using optical microscopy. The macropores were formed through the following four steps: phase separation (spinodal decomposition), coarsening, gelation, and evaporation of the solvent. The macropores can facilitate the rapid mass transfer between the outer and inner spaces of the TMPSQ microspheres. The TMPSQ microspheres are promising in various fields, such as catalyst supports and adsorbents. [ABSTRACT FROM AUTHOR]

Ten mixed‐ligand phenyl mercury(II) complexes containing 1‐methyl‐1H‐tetrazole‐5‐thiol (HmtzS) (1) and phosphine or amine ligands. These complexes fall into two groups: [PhHg(mtzS){Ph2P(CH2)PPh2}]2 (2) and [PhHg(mtzS){Ph2P(CH2)nPPh2}] (3‐6), where n varies, and [PhHg(mtzS)(diamine)] (8‐10), with diamine choices being 2,2′‐bipyridyl (Bipy, 8), 1,10‐phenathroline (Phen, 9), or ethylenediamine (en, 10). These complexes were synthesized with moderate to high yields and characterized using various techniques. Characterization data revealed that the mtzS− ligand coordinates as a monodentate ligand through the thiolate sulfur atom in all complexes, adopting a tetrahedral geometry around the Hg(II) center. Furthermore, complexes [PhHg(mtzS)] (1) and its diamine derivatives (8‐10) were assessed for hydrogen storage at 77 K using the VTI method. Results demonstrated that the incorporation of diamines improves hydrogen storage capacity at low pressure. The precursor stored (1) 2.3 wt.% at 80 bar, while the other complexes showed storage capacities ranging from 2.9 to 3.86 wt.% at pressures of 45‐60 bar. Thermodynamic properties of the [PhHg(mtzS)(Bipy)] complex was calculated at three different temperatures. The results prove that the entropy was equal to 0.50543599 J/mol H2. K while the enthalpy equal to 0.0942638 KJ/(mol H2). [ABSTRACT FROM AUTHOR]

Objective: The main aim of this study was to investigate the differences in maternal serum thiol/disulfide homeostasis among women with abortion imminens (AI), missed abortion (MA), and healthy pregnancies during the first trimester. Materials and Methods: This was a prospective case-control study. This study was conducted on pregnant women who visited the Obstetrics Clinic at University of Health Sciences Turkey, Etlik Zübeyde Hanım Gynecology Training and Research Hospital and were diagnosed with either AI or MA during the 6th to 14th weeks of pregnancy. The participants had a normal pregnancy follow-up, no chronic illnesses, and did not take any multivitamin or antioxidant supplements except for folic acid. The study incorporated 33 pregnant women with AI, 36 with MA, and 40 with normal pregnancies. Age, and body mass index were matched across the three groups. This study used a recently developed automated spectrophotometric technique to quantify thiol/disulfide concentrations. Results: The AI group had considerably elevated levels of total thiol and native thiol (SH) compared with the MA group. Nevertheless, there was no notable disparity observed between the group of healthy pregnancies and the other two groups. Serum disulfide (SS) levels did not exhibit any significant variations among the three groups. Similarly, the ratios of SS/SH, SS/total thiol, and SH/total thiol did not show any significant differences between the groups (p>0.05). Conclusion: Patients with MA had decreased levels of total thiol and SH, which possess antioxidant capabilities, compared to the AI group. A decrease in antioxidant levels in the body may contribute to the etiology of MA. When considering our findings alongside existing literature, it remains inconclusive whether the serum thiol-disulfide ratio can predict a healthy pregnancy or MA following AI. Therefore, it is not yet seen as a promising diagnostic tool for assessing pregnancy viability. Additional investigation is required to establish the influence of dynamic thiol/disulfide homeostasis on early pregnancy loss. Amaç: Bu çalışmanın temel amacı, ilk trimester abortus imminens (AI), düşük ve sağlıklı gebeliği olan kadınlarda anne serumu tiyol/disülfit dengesindeki farklılıkları incelemektir. Gereç ve Yöntemler: Bu çalışma, Sağlık Bilimleri Üniversitesi, Etlik Zübeyde Hanım Kadın Hastalıkları Eğitim ve Araştırma Hastanesi Kadın Doğum Kliniği'ne başvuran, 6 ile 14. haftalar arasında AI veya düşük tanısı almış, normal gebelik süreci geçiren, kronik hastalığı bulunmayan ve folik asit dışında herhangi bir multivitamin veya antioksidan takviyesi kullanmayan hamile kadınları içeren prospektif bir çalışmadır. Çalışma, 33 AI, 36 düşük tanısı konmuş ve 40 normal gebelik olgusunu kapsamaktadır. Katılımcıların yaş, ve vücut kitle indeksi her üç grup arasında eşitlenmiştir. Tiyol/disülfit seviyeleri, yeni geliştirilmiş bir otomatik spektrofotometrik yöntemle ölçülmüştür. Bulgular: AI grubunda, düşük grubuna göre anlamlı derecede yüksek olan toplam tiyol ve doğal tiyol (SH) seviyeleri saptanmıştır. Ancak, sağlıklı gebelik gösteren grup ile diğer iki grup arasında belirgin bir fark bulunmamıştır. Serum disülfit (SS) düzeyleri üç grup arasında istatistiksel olarak anlamlı bir farklılık göstermemiştir. Ayrıca, SS/SH, SS/toplam tiyol ve SH/toplam tiyol oranları gruplar arasında önemli bir fark göstermemiştir (p>0,05). Sonuç: Düşük olgularında AI grubuna kıyasla düşük toplam tiyol ve SH seviyeleri gözlemlenmiştir; her ikisi de antioksidan özelliklere sahiptir. Vücuttaki antioksidan seviyelerindeki azalma, düşüğün etiyolojisine katkıda bulunabilir. Bulgularımızı mevcut literatürle birleştirdiğimizde, serum tiyol-disülfit oranının AI sonrasında sağlıklı bir gebeliği ya da düşüğü öngörüp öngöremeyeceği konusunda kesin bir sonuca varılamamıştır. Dolayısıyla, gebeliğin sağlıklı ilerleyip ilerlemeyeceğini değerlendirmede umut verici bir tanı aracı olarak görülmemektedir. Erken gebelik kaybında dinamik tiyol/disülfit homeostazının etkisini göstermek için ek araştırmalara ihtiyaç vardır. [ABSTRACT FROM AUTHOR]

Rapid organic synthesis in reduced steps achieves cost-effectiveness by decreasing both the time and amount of material used to complete a reaction. This study explored the use of microwaves as an alternate energy source to drive the synthesis of thiols from their corresponding halides using potassium thioacetate as an inexpensive thiol source. Departing from previous synthetic routes, which require multiple steps and intermediate product isolation, the reported one-pot synthesis allows for direct conversion of the halide starting material to the corresponding thiol. This method works for alkyl halides, including straight chain, branched, or cyclic. This improved methodology was 6 to 24 times faster than previously reported synthetic methodologies and produced isolated yields of > 90%, a 1.25-fold improvement. [ABSTRACT FROM AUTHOR]

A number of Pt(II) complexes of 1-methyl-1H-1,2,3,4-tetrazole-5-thiol (Hmtzt) with phosphine ligands have been prepared and characterized and then evaluated as potential anti-cancer and ALP enzyme inhibitor agents. The complex [Pt(mtzt)2]2 was prepared by the reaction of 1-methyl-H1-tetrazole-5-thiol (Hmtzt) with K2PtCl4. This complex was treated with equivalent molar amounts of diphosphine ligands to afford complexes of the type [Pt(mtzt)2(PPh2(CH2)nPPh2)] in good yield, {PPh2(CH2)nPPh2, where n = 1 (dppm), n = 2 (dppe), n = 3 (dppp), n = 4 (dppb) and (PPh2((C5H4)2Fe)PPh2) (dppf)}. The prepared complexes were characterized by elemental analysis, IR, 1H-{31P} and 31P-{1H} NMR spectroscopy. The resulting data suggested that the prepared complexes were mononuclear with chelating diphosphines while the mtzt ligands were monodentate coordinating via the sulfur atom to give a square planner arrangement around the Pt(II) ion. This was confirmed by a single crystal structural analysis of the [Pt(mtzt)2(dppe)] complex. The Pt(II) complexes underwent structural optimization through the utilization of the DMol3 tool within the material studio package. A comparison of the results of molecular modelling with those of the X-ray structural analysis indicated that the structures were almost identical. The free ligand and two selected complexes were tested for inhibition activity against an alkaline phosphatase (ALP) enzyme, which was found to be active inhibitors, and the inhibition rate (37–88 %) range. Furthermore, the anticancer activity of the complexes (1, 3, and 6) was tested against human liver cancer (HepG2). The results showed that the prepared complexes have moderate activity but are lower than cis-platin. Complex 1 has the highest activity with an IC50 of 34.78 ± 1.75 M against the HepG2 cell line..

Objective: Studies have shown the complications of chemotherapy on learning and memory. Empirical evidence suggests that Nigella sativa (NS) has neuroprotective activities. Therefore, the aim of our study was to investigate the effects of NS on cisplatin-induced memory impairment.Materials and Methods: This study was conducted on 40 male rats grouped as: control (saline: 2 ml/kg, intraperitoneally (IP), once weekly/2 weeks), cisplatin (Cis, 2 mg/kg, IP, once weekly/2 weeks), NS (200 mg/kg, IP, once weekly/2 weeks), Cis +NS 200 (2 mg/kg Cis + 200 mg/kg NS, IP, once weekly/2 weeks), and Cis +NS 400 (2 mg/kg Cis + 400 mg/kg NS, IP, once weekly/2 weeks). Morris water maze (MWM) test was used to assess spatial learning and memory. In addition, superoxide dismutase (SOD) activity, and thiol and malondialdehyde (MDA) levels were evaluated in the brain.Results: Cis significantly enhanced the traveled distance and time spent in the target quadrant in the MWM test. Additionally, MDA levels increased in the Cis group, while thiol and SOD decreased in this group. As a result of treatment with NS, behavioral results were reversed in the groups receiving NS compared to the Cis group. Also, NS reduced MDA level but improved SOD and thiol levels in brain tissue samples.Conclusion: NS could improve memory impairment and oxidative stress in animals receiving Cis. Therefore, NS could be used as a potential food supplement to prevent neurotoxicity in patients undergoing chemotherapy.

Thiol-containing compounds, renowned as potent antioxidants, encompass various drugs and naturally occurring biological substances prevalent within the body. Aim of the study The study aimed to determine the level of inhibition of the photochemiluminescence reaction across therapeutic and physiological concentration ranges. Material and methods In order to quantify the in vitro antioxidant potential of these compounds photochemiluminescence technique was utilized. Eight bivalent sulfur compounds, predominantly derived from cysteine, were used: six with free SH groups (cysteine, homocysteine, N-acetyl-cysteine, captopril, glutathione, lipoic acid), one with a methylated SH group (methionine), and one with an oxidized SH group (cystine). Results After establishing a dynamic standard curve for UV-radiated oxidized luminol, the inhibitory effects of selected -SH containing compounds were investigated. It was observed that substances containing free SH groups diminished the intensity of light emission, contrasting with those containing blocked or oxidized thiols. The inhibition level appeared directly correlated with the antioxidant capacity of the compounds. Conclusions Glutathione demonstrated superior antioxidant activity across all tested concentrations.

INTRODUCTION: We aimed to analyze Total Oxidant Status (TOS), Total Antioxidant Status (TAS), Oxidative Stress Index (OSI) are determined in plasma and erythrocyte and thiol/disulfide and malondialdehyde (MDA) levels are determined in the plasma and erythrocyte of OCD patients and healthy controls. METHODS: Our study was conducted with 47 obsessive compulsive disorder patients and 49 healthy controls. All participants completed the sociodemographic data form, clinical global follow-up scale, and Yale Brown obsession-compulsion scale. Total Antioxidant Status (TAS), Total Oxidant Status (TOS) are determined in the plasma and erythrocyte, and malondialdehyde (MDA) and thiol/disulfide levels are determined in plasma. RESULTS: The comparison of the patient and control group plasma TAS, TOS, OSI and MDA levels revealed no statistically significant difference between these parameters. However, erythrocyte TAS was lower in the patient group (p

Cys is one of the least abundant amino acids in proteins. However, it is often highly conserved and is usually found in important structural and functional regions of proteins. Its unique chemical properties allow it to undergo several post-translational modifications, many of which are mediated by reactive oxygen, nitrogen, sulfur, or carbonyl species. Thus, in addition to their role in catalysis, protein stability, and metal binding, Cys residues are crucial for the redox regulation of metabolism and signal transduction. In this review, we discuss Cys post-translational modifications (PTMs) and their role in plant metabolism and signal transduction. These modifications include the oxidation of the thiol group (S-sulfenylation, S-sulfinylation and S-sulfonylation), the formation of disulfide bridges, S-glutathionylation, persulfidation, S-cyanylation S-nitrosation, S-carbonylation, S-acylation, prenylation, CoAlation, and the formation of thiohemiacetal. For each of these PTMs, we discuss the origin of the modifier, the mechanisms involved in PTM, and their reversibility. Examples of the involvement of Cys PTMs in the modulation of protein structure, function, stability, and localization are presented to highlight their importance in the regulation of plant metabolic and signaling pathways.

A copper‐mediated C(sp2)−H thiolation of pyrrole and indole derivatives with commercially available thiols utilizing a removable monodentate directing group is described. This protocol tolerated a broad range of functional groups and provided the thiolated products in 40 %–97 % yields. Furthermore, the synthetic utility of this protocol was demonstrated by the late‐stage functionalization of bioactive tryptophan peptide. Preliminary mechanistic studies indicated that a Cu(II)/Cu(III) reaction model is most likely to be involved in this C−H thiolation. [ABSTRACT FROM AUTHOR]

Covalent attachment of thiols to the tyrosine residues of silk fibroin is accomplished with a high degree of functionalization through the reaction of a pyridyldithiol‐containing N‐hydroxysuccinimidal‐ester and an amino‐tyrosine silk intermediate. The extent of thiol modification is characterized by 1H NMR and UV–vis spectroscopy. Further modification of the thiol groups is probed by reacting with an iodoacetamide‐containing small molecule resulting in a novel fluorescent silk derivative. Last, the ability of the thiolated silk to form hydrogels in situ is investigated. [ABSTRACT FROM AUTHOR]

Orogenic antimony-gold deposits contribute significantly to the global antimony resource base. China's orogenic antimony-gold deposits are primarily in southern Tibet. Investigations indicate that antimony combines and migrates with sulfur hydroxides in ore-forming fluids. Previous research on fluid inclusions in orogenic antimony-gold ores with sedimentary rock accommodation revealed the presence of organic inclusions, including liquid hydrocarbons, alongside common components such as CO2, H2O, CH4, and NaCl. However, the impact of liquid hydrocarbons on antimony migration and mineralization is still debatable. To investigate the transportability of antimony by liquid hydrocarbons in orogenic antimony ores, we selected n-dodecanethiol and n-dodecane as the subjects. We measured the solubility and occurrence form of antimony in these compounds at various temperatures and durations. The results indicate that after 5 and 10 days of reaction at 100 °C, the antimony concentrations in the n-dodecanethiol and n-dodecane groups were 67.44 ± 7.62 ppm, 75.15 ± 16.74 ppm, 1.40 ± 1.02 ppm, and 3.02 ± 3.09 ppm, respectively. At 150 °C for 5 and 10 days, the respective concentrations were 50.58 ± 5.39 ppm, 77.26 ± 45.20 ppm, 2.66 ± 3.08 ppm, and 2.41 ± 2.03 ppm. At 200 °C for 5 and 10 days, the corresponding concentrations were 339.76 ± 71.94 ppm, 218.97 ± 25.03 ppm and 6.53 ± 7.17 ppm, 2.27 ± 0.82 ppm (n = 3). The measured solubility of antimony in the n-dodecanethiol group increased gradually with rising temperature. The solubility of antimony in the n-dodecane group was low and notably inferior to that observed in the n-dodecanethiol group. X-ray photoelectron spectroscopy (XPS) analysis demonstrated a distinct thiol (R-SH) peak at 163.31 eV and compound peaks of antimony reacting with thiols at 162.06 and 160.87 eV. This suggests that antimony predominantly forms complexes with thiols for migration. Our findings suggest that specific liquid hydrocarbon components, predominantly thiols, can interact with antimony at metallogenic temperatures and persist in ore-forming fluids, facilitating migration and mineral enrichment. Earlier experimental studies on gold and crude oil have indicated that liquid hydrocarbons also play an essential role in the transportation and enrichment of gold during the formation of gold deposits, thus indicating that liquid hydrocarbons possess the considerable potential to act as an ore-forming fluid during orogenic antimony-gold deposit formation in southern Tibet. [ABSTRACT FROM AUTHOR]

A new one‐pot solvent‐less reaction to convert benzylic, allylic, ferrocenyl or tertiary alcohols into S‐thioesters, bench‐stable and less odorous precursors of the corresponding thiols, which is based on reactions in neat thioacetic acid in the presence of tetrafluoroboric acid, is presented. Reaction monitoring by NMR and GC of the benzyl alcohol conversion indicated the intermediate formation of benzyl acetate and benzyl thionoacetate (PhCH2OC(S)CH3) prior to the slower conversion to the final S‐benzyl thioacetate product. Increasing the HBF4 concentration enhanced the reaction rate, giving good to excellent yield (up to 99 %) for a large scope of alcohols. Control experiments, with support of DFT calculations, have revealed a thermodynamically favorable, though requiring HBF4‐activation, disproportionation of CH3C(O)SH to CH3C(O)OH and CH3C(S)SH, the latter immediately decomposing to H2S and (MeC)4S6 but also generating the hitherto unreported [MeC(O)C(Me)S]2(μ‐S)2. Kinetic investigations demonstrated that the rate of benzyl alcohol conversion is second‐order in [PhCH2OH] and second order in [HBF4], while the rate of conversion of the benzyl acetate intermediate to S‐benzyl thioacetate is second order in [PhCOOMe] and fourth order in [HBF4]. The DFT calculations rationalize the need to two alcohol molecules and two protons to generate the reactive benzyl cation. [ABSTRACT FROM AUTHOR]

Objective: Recent evidence suggests that oxidative stress contributes to the pathophysiology of schizophrenia. This study aimed to compare thiol-disulphide homeostasis in acute and stable phases of schizophrenia for the first time. Methods: Among the patients with schizophrenia, 61 in the acute-phase and 61 in the stable phase of their illness were enrolled in the study. Native thiol (NT), total thiol (TT), disulphide (SS), disulphide/native thiol, disulphide/total thiol, and native thiol/total thiol for thiol-disulphide homeostasis were compared between the groups. The Brief Psychiatric Rating Scale (BPRS), Scale for the Assessment of Positive/Negative Symptoms (SAPS/SANS), Clinical Global ImpressionSeverity Scale (CGI-S), Barnes Akathisia Rating Scale, and Simpson-Angus Scale were used to assess symptoms. Results: After controlling for age, sex, body mass index, and smoking status there were significant differences in NT, TT, SS/NT, SS/TT, and NT/TT, but not SS. Thiol/disulphide homeostasis has shifted in favour of the oxidative side in patients with acute-phase compared to that in stable schizophrenia. BPRS, SAPS, and CGI-S scores were significantly correlated with all six thiol-disulphide parameters, but not SANS, when controlling for age and sex. Significant receiver operating characteristic (ROC) curves were obtained for all thiol-disulphide homeostasis parameters. Discriminant analysis was found to be statistically significant in discriminating between groups. Conclusion: These results show that oxidative status increases thiol-disulphide homeostasis in patients with acute-phase schizophrenia compared to those with stable schizophrenia. These findings suggest that thiol-disulphide parameters can be used as biomarkers for the acute exacerbation of schizophrenia. [ABSTRACT FROM AUTHOR]

Objective: Studies have shown the complications of chemotherapy on learning and memory. Empirical evidence suggests that Nigella sativa (NS) has neuroprotective activities. Therefore, the aim of our study was to investigate the effects of NS on cisplatin-induced memory impairment. Materials and Methods: This study was conducted on 40 male rats grouped as: control (saline: 2 ml/kg, intraperitoneally (IP), once weekly/2 weeks), cisplatin (Cis, 2 mg/kg, IP, once weekly/2 weeks), NS (200 mg/kg, IP, once weekly/2 weeks), Cis +NS 200 (2 mg/kg Cis + 200 mg/kg NS, IP, once weekly/2 weeks), and Cis +NS 400 (2 mg/kg Cis + 400 mg/kg NS, IP, once weekly/2 weeks). Morris water maze (MWM) test was used to assess spatial learning and memory. In addition, superoxide dismutase (SOD) activity, and thiol and malondialdehyde (MDA) levels were evaluated in the brain. Results: Cis significantly enhanced the traveled distance and time spent in the target quadrant in the MWM test. Additionally, MDA levels increased in the Cis group, while thiol and SOD decreased in this group. As a result of treatment with NS, behavioral results were reversed in the groups receiving NS compared to the Cis group. Also, NS reduced MDA level but improved SOD and thiol levels in brain tissue samples. Conclusion: NS could improve memory impairment and oxidative stress in animals receiving Cis. Therefore, NS could be used as a potential food supplement to prevent neurotoxicity in patients undergoing chemotherapy. [ABSTRACT FROM AUTHOR]

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Multiphasic studies were conducted to quantify how sulfur fertilization influences nitrate levels in hops, and how nitrogen and sulfur fertilizer dose jointly affect hop yield, brewing chemistry, and aroma of hops and beer. In an observational study of commercial lots of Simcoe® hops, a weak positive correlation was found between sulfur and nitrate concentrations. In field studies with Simcoe® in Washington, factorial combinations of representative low and high rates of nitrogen and sulfur fertilizer revealed that nitrate content of cones increased 13 to 22% with increasing nitrogen dose yet declined 8 to 8.7% with an increasing sulfur dose. Yield was unaffected by the lower dose of nitrogen when sulfur dose was high; effects on α-acids, total oil, and hop and beer aroma were not detected. Cysteine-3SH and cysteinylglycine-3SH were reduced 19% and 23%, in cones that received the higher sulfur dose in one year; other thiols and precursors were unaffected. In cultivar Willamette in Oregon, increasing sulfur dose over an 11-fold range by varying nitrogen fertilizer form from urea to ammonium sulfate had small to non-detectable effects on yield, α-acids, or nitrate concentrations. Hop aroma and brewing characteristics appear largely invariant to sulfur fertilization; increased sulfur fertilization may reduce hop nitrate levels modestly in certain situations. [ABSTRACT FROM AUTHOR]

Summary: Reducing agents and oxidizing agents have been identified as contributors to vitamin B12 losses associated with food processing and/or storage. We evaluated the effects of redox active agents on cyanocobalamin stability in heat‐treated non‐fat milk and neutral pH buffers. The largest average cyanocobalamin losses occurred in the presence of an added thiol (glutathione, cysteine, dithiothreitol and the thiamine decomposition product 2‐methyl‐3‐furanthiol) or dithionite, whereas cyanocobalamin recoveries generally increased in the presence of an added oxidizing agent. Cyanocobalamin instability in the heat‐treated, non‐fat milk (~40% loss after 90 min at 100 °C) was attributed to a combination of heat, cystine/cysteine, oxygen and a low‐level presence of transition metals, a combination also found in many other foods for which B12 instability has been reported. The proposed cyanocobalamin decomposition pathway – complexation with heat‐exposed cysteine thiolate, cobalt reduction, hydrolysis of the complex, conversion to hydroxocobalamin and irreversible oxidation – follows the sequence described by others. [ABSTRACT FROM AUTHOR]