Cysteine Research Articles

Antimicrobial Preparations Based on L-Cysteine, Silver Acetate, and PHMG-HC for Impregnation of Chemical Fibers and Textiles

Hydrogels prepared from L-cysteine, silver acetate, and polyhexamethyleneguanidine hydrochloride (PHMG-HC) were used in rheological, structural, and antibacterial studies. Aqueous solutions of Lcysteine and silver acetate were found to be very miscible with aqueous solutions of PHMG-HC to form transparent hydrogels. A model for the three-dimensional structure of the gel network was proposed. The hydrogel exhibited high antimicrobial activity against test cultures of pathogenic and conditionally pathogenic microorganisms.

Up-regulation of Nrf2/P62/Keap1 involves in the anti-fibrotic effect of combination of monoammonium glycyrrhizinate and cysteine hydrochloride induced by CCl4

Combination of monoammonium glycyrrhizinate and cysteine hydrochloride (MG-CH) has been used in the treatment of chronic liver disease for decades, however, its mechanism is still unclear. Our previous studies showed that MG-CH confers the optimal therapeutic effect at the ratio of 2:1 to against acute liver damage. In this study, it was used to investigate the anti-fibrotic effect induced by CCl4. The results showed that injection of MG-CH produced anti-fibrotic effect ranged from 30 mg/kg to 60 mg/kg, evidenced by decreased the collagens deposition and inhibited the production of hydroxyproline. Mechanism study found that Nrf2/ARE signaling pathway was activated by MG-CH, whereas loss of hepatocytic Nrf2 abolished its anti-fibrotic effect significantly. Furthermore, it was demonstrated that MG-CH is a non-canonical NRF2 inducer, which promoted the autophagy activity and release the Nrf2 from keap 1 by promoting the phosphorylation of p62 at Ser351. Knockdown of p62 abolished the enhancement of nuclear accumulation of Nrf2 by MG-CH. All of these results suggested that up-regulation of Nrf2/P62/Keap1 involves in the anti-fibrotic effect of MG-CH, which provide a rational explanation for the usage of MG-CH in the treatment of fibrosis.

Influence of dissolved organic matter on carbonyl sulfide and carbon disulfide formation from dimethyl sulfide during sunlight photolysis.

Carbonyl sulfide (COS) and carbon disulfide (CS2 ) are important atmospheric gases photochemically generated from organic sulfur precursors in sunlit natural waters. This study examined these processes by evaluating COS and CS2 photoproduction from dimethyl sulfide (DMS) in the presence of dissolved organic matter (DOM). DOM was added because it photochemically produces various reactive intermediates (3 CDOM*, • OH, 1 O2 , and H2 O2 ) potentially involved in these reaction pathways. DMS-amended synthetic waters at pH 8 were varied in terms of their DOM type and concentration, spiked with the 3 CDOM* quenching agent, phenol, in certain cases, and subsequently irradiated over varying exposure times. Results indicated that various DOM types ranging from freshwater to open-ocean DOM increased COS but did not alter CS2 , which remained at nondetect levels. DOM type influenced COS only at higher concentrations (20 mg/L), whereas increasing DOM concentrations proportionally increased COS concentrations for all DOM types. Phenol addition lowered COS formation for reasons that remained unclear because phenol likely quenched 3 CDOM* and DMS-derived sulfur-based radicals. Further comparisons with DMS-spiked natural waters and cysteine (CYS)-spiked synthetic and natural waters assessed previously indicated that COS formation from both precursors in natural waters was always greater than in waters containing DOM alone. PRACTITIONER POINTS: DMS- and DOM-spiked synthetic waters formed COS but did not form CS2 during sunlight photolysis. In DMS-spiked synthetic solutions, DOM type has a limited influence on COS formation whereas DOM concentration has a stronger influence on COS formation. COS formation in the DMS-spiked synthetic waters was fairly proportional to the DOC concentration but was generally lower than COS formation in DMS-spiked natural waters.

Comparative structural, linear-non-linear optical, laser damage threshold, dielectric and thermal analysis of pristine and L-cysteine influenced KH2PO4 crystal for NLO applications

Current comparative investigation explores the structural, optical, frequency conversion efficiency, laser damage threshold, dielectric and thermal traits of undoped and L-cysteine (LC) doped potassium dihydrogen phosphate (KDP) crystal grown by slow solvent evaporation method. The qualitative analysis of LC doped KDP crystal has been performed by means of fourier transform infrared analysis. Powder X-ray diffraction technique has been employed to assess the crystallinity, purity and unit cell values of LC doped KDP crystal. UV–visible study has been carried out within 200–900 nm to probe the effect of LC on transmittance of KDP. In LC doped KDP, large boost in second harmonic generation due to charge delocalization phenomenon has been ascertained by Kurtz-Perry test. The laser induced damage resistance of LC doped KDP crystal has been determined by 1064 nm laser and it is valued to be 5.31 GW/cm2. The dielectrics of undoped and LC doped KDP crystals have been investigated by means of dielectric characterization study. The thermal parameters of LC doped KDP crystal has been examined using thermogravimetric and differential scanning calorimetry.

Exploiting styrene-maleic acid copolymer grafting chromatographic stationary phase materials for separation of membrane lipids

High performance liquid chromatography-mass spectrometry is one of the most commonly used strategies for lipid analysis. The development of versatile chromatographic stationary phases to meet the increasing demands for separation of complex lipids is very important. Styrene-maleic acid (SMA) copolymer is an amphiphilic polymer, which has been proven to have the ability to solubilize lipid molecules of various structures. In this study, styrene-maleic anhydride copolymer coated silica was first prepared by the thiol-ene click reaction. With l-cysteine hydrochloride or dodecanol as the post-modification reagents, Sil-SMA-amino acid and Sil-SMA-dodecanol stationary phase materials were further successfully fabricated via nucleophilic ring-opening reaction. The Fourier-transform infrared, thermogravimetric analysis, and elemental analysis results confirmed the two stationary phase materials were successfully prepared. Furthermore, both the Sil-SMA-dodecanol column and the Sil-SMA-amino acid column possessed reversed-phase/hydrophilic interaction/ion exchange mixed-mode retention mechanisms. The column efficiency of the Sil-SMA-derivatives columns reached 77,300 N/m. Based on the mixed-mode retention characteristics, the Sil-SMA-derivatives columns achieved both the lipid classes and species separation via a single column. The Sil-SMA-amino acid column was further successfully used to separate lipid extract from gastric cancer cell membrane. All these results demonstrated that the SMA-based stationary phase materials have a good potential for use in lipid separation.

Competitive exchange between divalent metal ions [Cu(II), Zn(II), Ca(II)] and Hg(II) bound to thiols and natural organic matter

Mercuric Hg(II) ion forms exceptionally strong complexes with various organic ligands, particularly thiols and dissolved organic matter (DOM) in natural water. Few studies, however, have experimentally determined whether or not the presence of base cations and transition metal ions, such as Ca(II), Cu(II), and Zn(II), would compete with Hg(II) bound to these ligands, as concentrations of these metal ions are usually orders of magnitude higher than Hg(II) in aquatic systems. Different from previous model predictions, a significant fraction of Hg(II) bound to cysteine (CYS), glutathione (GSH), or DOM was found to be competitively exchanged by Cu(II), but not by Zn(II) or Ca(II). About 20–75% of CYS-bound-Hg(II) [at 2:1 CYS:Hg(II)] and 14–40% of GSH-bound-Hg(II) [at 1:1 GSH:Hg(II)] were exchanged by Cu(II) at concentrations 1–3 orders of magnitude greater than Hg(II). Competitive exchange was also observed between Cu(II) and Hg(II) bound to DOM, albeit to a lower extent, depending on relative abundances of thiol and carboxylate functional groups on DOM and their equilibrium time with Hg(II). When complexed with ethylenediaminetetraacetate (EDTA), most Hg(II) could be exchanged by Cu(II) and Zn(II), as well as Ca(II) at increasing concentrations. These results shed additional light on competitive exchange reactions between Hg(II) and coexisting metal ions and have important implications in Hg(II) chemical speciation and biogeochemical transformation, particularly in contaminated environments containing relatively high concentrations of Hg(II) and metal ions.

Development, optimization, and validation of a method for detection of cartap, thiocyclam, thiosultap-monosodium, and thiosultap-disodium residues in plant foods by GC-ECD

A method was developed for the simultaneous determination of four nereistoxin-related pesticides, viz. cartap, thiocyclam, thiosultap-monosodium, and thiosultap-disodium, in 20 plant foods. The samples were extracted using a hydrochloric acid solution containing cysteine hydrochloride, derivatized to nereistoxin under alkaline conditions, and analyzed by gas chromatography with electron capture detector. The average recoveries of the method were 72–108%, with relative standard deviations (RSDs) of 0.3–14.7% (n = 1200, p < 0.05). The intermediate precision and reproducibility experiments using established methods were also carried out. All the results passed the Cochrane and Grubbs tests (n = 2400, p < 0.05). The RSDs of intermediate precision and RSDs of reproducibility among laboratories were in the ranges 1.7–10.9% and 2.4–15.3% (n = 2400, p < 0.05), respectively, indicating that the accuracy and precision of the method are satisfactory. This method can be used to detect nereistoxin-related pesticides in plant foods.

An investigation on corrosion properties of bright Zn‐Ni alloy coated mild steel

AbstractIn the present work, the electrodeposition of Zn–Ni alloy from Sulfate bath was carried out in presence of a novel brightener (CG), the condensation product of Cysteine Hydrochloride and Glutaraldehyde. The corrosion studies were carried out using Electrochemical Impedance spectroscopy and Potentiostatic techniques. They confirmed an increase in corrosion resistance and protection ability of bright zinc–nickel alloy coatings. Surface morphology was studied using SEM, FTIR, and reflectance spectroscopy that revealed fine‐grained nature of Zn‐Ni alloy crystallites. X‐ray diffraction studies were used for phase identification and preferred orientation of Zn–Ni alloy crystallites. The preferred orientation of the Zn‐Ni alloy crystallites along (630) planes was configured for bright appearance of the coating. CG was successful in giving an even, homogeneous, refined, and bright Zn‐Ni alloy deposit.

Preparation and Properties of Papain Precipitated from Fresh Latex of Papaya Fruits (Carica papaya)

Papain was precipitated from cysteine hydrochloride extract of fresh latex of papaya fruits planted in AlexandriaGovernorate, Egypt. Three precipitants; namely, ethyl alcohol, acetone and sodium chloride resulted in proteolyticactivity recovery 84.8 (of three fractions), 85.2 and 76.7 %, respectively. Acetone was found to be the most promisingrapid and simple conditions for preparing acetone dry powder of partially purified crude papain. Papain propertiesindicated that the maximum activity was attained at pH 7.5–8.0, and temperature of 75 -85°C. The activity was notaffected by Na+ or Ca++ ions. Various degrees of inhibition were exerted by Ni+,+, Co++, Pb ++,and Hg++., while Cu++,caused complete inhibition .On the other hand, the proteolytic activity increased to various levels, in the presenceof Sn++, cyanide, thioglycolic acid, and cysteine hydrochloride. The catalytic activation (49%) of Sn++ was found todepend to some extent on the concentration. A mixed stored papain-oryzae protease preparation ,was found to retain71, 63, and 54 % of its proteolytic activity upon storage at 25°C for 1, 2 ,and 3 months ,respectively. The retainedactivity was more pronounced, being 92, 80,and 69 %, respectively upon storage at –5°C for the aformentioned durations,accordingly, storage at –5°C for up to 2 months, was recommended. The storage stability of papain powder andsolutions were studied. A papain-oryzae protease preparation was formulated for further use in meat tenderization.

Application of a Reactive Oxygen Species-Responsive Drug-Eluting Coating for Surface Modification of Vascular Stents.

Stent implantation is the primary method used to treat coronary heart disease. However, it is associated with complications such as restenosis and late thrombosis. Despite surface modification being an effective way to improve the biocompatibility of stents, the current research studies are not focused on changes in the vascular microenvironment at the implantation site. In the present study, an adaptive drug-loaded coating was constructed on the surface of vascular stent materials that can respond to oxidative stress at the site of vascular lesions. Two functional molecules, epigallocatechin gallate (EGCG) and cysteine hydrochloride, were employed to fabricate a coating on the surface of 316L stainless steel. In addition, the coating was used as a drug carrier to load pitavastatin calcium. EGCG has antioxidant activity, and pitavastatin calcium can inhibit smooth muscle cell proliferation. Therefore, EGCG and pitavastatin calcium provided a synergistic anti-inflammatory effect. Moreover, the coating was cross-linked using disulfide bonds, which accelerated the release of the drug in response to reactive oxygen species. A positive correlation was observed between the rate of drug release and the degree of oxidative stress. Collectively, this drug-loaded oxidative stress-responsive coating has been demonstrated to significantly inhibit inflammation, accelerate endothelialization, and reduce the risk of restenosis of vascular stents in vivo.

Color and structural modifications of alkaline extracted sunflower protein concentrates and isolates using L-cysteine and glutathione

Alkaline sunflower protein extraction can be performed along with de-phenolization of sunflower seed proteins if greening is unwanted. This greening is promoted at alkaline pH when chlorogenic acid (CGA) oxidizes and reacts with amino acids such as lysine. Thiol-containing dough conditioners: L-cysteine hydrochloride and glutathione (GSH) were investigated as an alternative de-greening strategy to acidification and de-phenolization. Greening and browning inhibition of thiols (GSH and Cysteine) were modeled by a combination of additive and interaction effects of extraction pH (7.0 to 11.0) and thiol concentration (0.00 to 5.60 mM) randomly assigned by Response Surface Methodology (RSM). The powders with the highest greening were the controls (pH 8.9–9.3 and no added thiols) and powders at pH 10.41 with 0.82 mM thiols. From RSM, the maximum greening inhibition was achieved at pH 8.71 and 4.23 mM cysteine, and pH 8.51 and 3.78 mM GSH. However, cysteine caused more browning at alkaline pH than GSH. Furthermore, fluorescence spectroscopy showed that cysteine had a protective effect against alkaline unfolding, whereas GSH quenched fluorescence in a concentration-dependent manner. Overall, de-greening of alkaline extracted sunflower protein was achieved by adding cysteine or glutathione, but the thiols differed in their contribution to the browning and unfolding effect.

Synthesis of Cadmium Telluride Nanoparticles Using Thioglycolic Acid, Thioglycerol, and L-Cysteine.

Cadmium telluride (CdTe) nanoparticles (NPs) are known for their unique physical and chemical properties. NP synthesis via a size-controlled procedure has become an intriguing research topic because NPs exhibit novel optical and physical properties depending on their size. Their sizes and properties can vary depending on the types and concentrations of stabilizers, which are bound to the surface of the NPs and protect the NPs from aggregation. In this study, we synthesized CdTe NPs stabilized by thioglycolic acid (TGA), 1-thioglycerol (TGC), and L-cysteine (L-C). The ratio of stabilizer to Cd2+ was 1:2.4. Transmission electron microscopy (TEM), X-ray diffraction (XRD), and photoluminescence (PL) were employed for characterization of the NPs. The average sizes of the synthesized NPs were 4.2, 4.1, and 3.7 nm for TGA, TGC, and L-C, respectively. The maximum fluorescent emission peaks of the three NP solutions were at 554.9, 551.6, and 538.3 nm for TGA, TGC, and L-C, respectively. The produced particles were crystalline in structure with a face-centered cubic (fcc) system.

Oxidative stress concept updated: Definitions, classifications, and regulatory pathways implicated.

Reactive oxygen species were discovered in living organisms in the early 1950's and their action has been implicated in diverse biological processes. First formulated by H. Sies in 1985[57], the oxidative stress concept stimulated substantial interest in reactive oxygen species and it is now common that fundamental research in various biomedical fields includes mention of research on the involvement of oxidative stress. Such strong interest has resulted in the development of definitions and classifications of oxidative stress and much research progress in the field. Although we clearly understand the limitations of various definitions or classifications, such parameters may help to provide quantitative descriptions, compare related processes among different laboratories, and introduce some measurable parameters. This paper highlights recent advances in the areas of oxidative stress definitions and the classification of oxidative stresses. Such items are directly associated with our understanding of the molecular mechanisms involved in organismal responses to oxidative insults. The knowledge accumulated to date indicates that selective expression of specific genes is a central player in the adaptive response to oxidative stress and reversible oxidation of cysteine residues of sensor proteins is a key process regulating responses to oxidative stress.

Role of Cysteine in Enhanced Degradation of Trichloroethane under Ferrous Percarbonate System

The removal of toxic contaminants such as trichloroethane (TCA) from groundwater had a huge impact due to associated health hazards. Advanced oxidation technology has an outstanding potential to remove these toxins. However, the redox cycling of Fe(II)/Fe(III) is mostly a barrier for the efficient removal of these contaminants. In this study, we extracted two in one nature of cysteine (CYS) to enhance TCA degradation in Fe(II)/sodium percarbonate (SPC) system. The chelating and reducing capability of CYS, concentration impact of Fe(II), SPC, and pH role were all thoroughly investigated. The existence of hydroxyl (OH●) and superoxide (O2–●) radicals were confirmed through quencher tests. Furthermore, the electron paramagnetic resonance (EPR) spectra evaluated the enhancement of OH● radicals in the Fe(II)/CYS/SPC system due to the electron transfer capability of CYS. The Fe(II)/CYS/SPC showed excellent recyclability and stability characteristics up to 68% TCA degradation in the fourth round. The degradation products and dechlorination analysis confirmed the existence of non-toxic final products. Similarly, the system demonstrated admirable performance in a real groundwater system, bolstering its real-time industrial applications. Conclusively, Fe(II)/CYS/SPC can be a viable and effective method for degrading chlorinated organic hydrocarbons in groundwater.

Biomedical features of flaxseed against different pathologic situations: A narrative review.

Flaxseed is a plant that grows and is cultivated in more than 50 countries; the main flax producer countries are Canada, China, the United States, and India. The purpose of the present study was to overview the source, chemical compounds, and mechanisms of the therapeutic effects of this valuable plant. For writing this manuscript, we made a list of relevant keywords and phrases, and then we started searching for studies in PubMed, Scopus, and Web of Science databases. The main constituents of flaxseed include lipids, proteins, lignans, fibers, and minerals. Flaxseed is full of antioxidants such as tocopherols, betacarotene, cysteine, and methionine which result in a decrease in blood pressure, heart disease, hepatic and neurological disorders, and increased insulin sensitivity. Flaxseed is commonly used for its antidiabetic and anticancer activities and also it is beneficial for cardiovascular, gastrointestinal, hepatic, urological, and reproductive disorders, and because of these beneficial effects, it is recognized as a medical plant.

Mapping the cysteine redoxome: advances and prospects

Mapping the cysteine redoxome: advances and prospects

Characterization of aroma in response surface optimized no-salt bovine bone protein extract by switchable GC/GC×GC-olfactometry-mass spectrometry, electronic nose, and sensory evaluation

No-salt bovine bone protein extract (NS-BBPE) is rich in bone collagen, peptides and amino acids and is useful in the food industry. However, NS-BBPE has a more monotonous taste than bovine bone protein extract (BBPE), so BBPE is more useful than NS-BBPE. According to the World Health Organization, adults who eat less than 6 g/d have improved health. Odor-induced saltiness (OISE) is a way to reduce the amount of NaCl in food. The multisensory interaction between aroma (meaty and roasted) and taste can be used to compensate for the saltiness perception of healthy low-salt food. In this study, the optimal Maillard conditions from response surface optimization were as follows: temperature, 105 °C; time, 20 min; reducing sugar addition, 1 g; EH-NS-BBPE, 30 g; water, 10 g; hydrolyzed vegetable protein (HVP), 5 g; bovine tallow, 3 g; L-Cys, 0.5 g; cysteine hydrochloride, 1 g; VB1, 0.4 g; and I+G, 0.5 g. The salt-congruent aroma was produced from the Maillard reaction products of NS-BBPE, which was detected by a new SGC/GC2-O-MS system. Electronic nose analysis of the difference in aroma and sensory evaluation proved that salt-congruent aroma was present in the samples.

A novel method of water remediation of organic pollutants and industrial wastes by solution- route processed CZTS nanocrystals

CZTS (Cu2ZnSnS4), a P-type semiconductor with a direct bandgap (1.2–1.7eV), earth-abundant, non-toxic, and has a large absorption coefficient makes it extremely useful in optoelectronics and light-harvesting applications. In this work, CZTS is prepared by an ingenious, cost-effective colloidal route using the ‘hot-injection’ method with the usage of different ligands. The XRD and Raman spectroscopy shows the single-phase highly crystalline CZTS nanoparticles with kesterite structure. The TEM results show that the size of CZTS nanoparticles is about 2–5 nm and monodispersity is confirmed by DLS (Dynamic Light Scattering). FTIR confirms the presence of different ligands used in CZTS preparation. The Uv–vis absorption shows the direct bandgap of 1.5–1.7eV. The contact angle study shows the hydrophobic nature of as-synthesized CZTS nanoparticles which were further ligand exchanged with l-cysteine hydrochloride to make it hydrophilic to study the photocatalytic degradation activity of organic pollutants and industrial waste in the water. The photocatalysis experiments were performed under two conditions: (i) under bare sunlight (Intensity ∼ 900 W/m2) (ii) focussing the sample under the sunlight via converging lens (1800 W/m2). The photocatalytic efficiencies were then compared and the best photocatalytic efficiency achieved under sunlight was 98.4% for organic pollutants and 75% for industrial waste via converging lens while the corresponding efficiencies with bare sunlight were 98.1% and 73% respectively. To the best of the author’s knowledge, a rapid and highly efficient photocatalysis of CZTS NPs employing a converging lens for water-remediation without the usage of noble & transition-metals has been reported for the first time.

Interaction of M@Au12 nanocluster (M = Au, Ag, Pd, and Pt) with different forms of cysteine (uncharged, cationic, anionic, and zwitterion) via the Au-S bond

In this work, the effect of the type of core-metal (M = Au, Ag, Pd, and Pt) of a M@Au12 nanocluster on its interaction with the different forms of cysteine (CYS) (uncharged, anionic, cationic, and zwitterion) via the formation of Au-S bond is investigated. Other issues considered in this investigation are the adsorption energy and adsorption mode, the strength of the Au-S bond, and the IR spectrum of the considered forms of CYS. Also, the effect of the type of M on the combination of the frontier molecular orbitals of the considered CYS forms with the molecular orbitals of metal nanoclusters is investigated. The interaction of the CYS, in its zwitterion form, with the considered nanoclusters, is studied in the microhydration, water considering the polarized continuum model (PCM), and PCM + microhydration environments, separately. The selected metal nanoclusters can be considered as small models of the core-shell nanoparticles to see how the type of core-metal atoms influences the interaction of different forms of CYS with the core-shell nanoparticles.

Suspecting classical homocystinuria in an adolescent born before the newborn screening program

Introduction: Classical homocystinuria (HCU) is an autosomal recessive disorder caused by a deficiency in the cystathionine beta-synthase enzyme and associated with a high probability of vascular complications. Herein is presented the case of an adolescent diagnosed with HCU during cerebral venous sinus thrombosis (CVST) study. Case Report: A 14-year-old girl presented with thrombophilia screening tests suggestive of HCU during CVST study. After referral to an Inherited Metabolic Diseases Unit, she started supplementation with pyridoxine, folic acid, vitamin B12, betaine anhydrous, and cysteine and was advised to restrict natural proteins and methionine from diet. Genetic analysis revealed a homozygous CBS mutation (c.572C>T (p.T191M) with c.699C>T (p.Y233Y) polymorphism. Discussion: In adolescents born before 2004 (year of implementation of the Portuguese newborn screening program), HCU should be considered when studying hypercoagulability syndromes, as it is a treatable condition and treatment can prevent major morbidity and mortality causes.