Carboxymethyl Groups Research Articles

Fabrication of yeast β-glucan/sodium alginate/γ-polyglutamic acid composite particles for hemostasis and wound healing.

Particles with a porous structure can lead to quick hemostasis and provide a good matrix for cell proliferation during wound healing. Recently, many particle-based wound healing materials have been clinically applied. However, these products show good hemostatic ability but with poor wound healing ability. To solve this problem, this study fabricated APGG composite particles using yeast β-glucan (obtained from Saccharomyces cerevisiae), sodium alginate, and γ-polyglutamic acid as the starting materials. The structure of yeast β-glucan was modified with many carboxymethyl groups to obtain carboxymethylated β-glucan, which could coordinate with Ca2+ ions to form a crosslinked structure. A morphology study indicated that the APGG particles showed an irregular spheroidal structure with a low density (<0.1 g cm-3) and high porosity (>40%). An in vitro study revealed that the particles exhibited a low BCI value, low hemolysis ratio, and good cytocompatibility against L929 cells. The APGG particles could quickly stop bleeding in a mouse liver injury model and exhibited better hemostatic ability than the commercially available product Celox. Furthermore, the APGG particles could accelerate the healing of non-infected wounds, and the expression levels of CD31, α-SMA, and VEGF related to angiogenesis were significantly enhanced.

Saccharide branched cellulose with controllable molecular structure and excellent water retention ability

In this work, saccharide branched cellulose (saccharide b-Cel) was synthesized by combining reducing saccharides with cellulose molecules using Ugi four-component reaction (Ugi-4CR). First, the carboxyl groups required for Ugi-4CR are obtained by carboxymethylating cellulose molecules. Then, saccharide b-Cel with a controlled molecular structure is formed when the terminal aldehyde group of reducing saccharides combines with the carboxyl group and auxiliary functional group. The types of saccharides, the degree of substitution of carboxymethyl groups, and the degree of branching all affect the molecular structure of saccharide b-Cel. Through molecular structural regulation, the relationship between the branching structure and water retention ability of saccharide b-Cel was examined in detail. This work not only provides new insights into the synthesis of cellulose derivatives, but it also provides a template for the synthesis of other biomass derivatives.

Mechanism for the seleikctive adsorption of uranium from seawater using carboxymethyl-enhanced polysaccharide-based amidoxime adsorbent

Land-based uranium resources are becoming scarce because of the widespread development and use of nuclear energy. Therefore, to make up for the shortage of uranium resources, a new chitosan/carboxymethyl-β-cyclodextrin/quaternary ammonium salt–functionalized amidoxime carbon adsorbent (CSAOCF) was designed and synthesized for extracting uranium from seawater. Experimental studies show that the adsorption of uranium by CSAOCF is a spontaneous endothermic reaction and chemical adsorption. The theoretical maximum adsorption capacity of uranium can reach 726 mg/g at 308 K and pH = 6. Moreover, the adsorption efficiency and selectivity of CSAOCF for uranium were significantly improved after the introduction of the carboxymethyl group, and the selection and partition coefficient of CSAOCF for uranium and vanadium increased from 16-fold to 30-fold under the same conditions. This indicates that there is a synergistic effect between carboxyl and amidoxime groups, which can promote the adsorption of uranium by CSAOCF. Furthermore, CSAOCF exhibits good oil resistance and can be reused more than five times. Therefore, CSAOCF containing carboxymethyl and amidoxime functional groups can considerably improve the selective adsorption of uranium and has great potential in the extraction of uranium from seawater.

A Co-based nitrogen-doped lignin carbon catalyst with high stability and wide operating window for rapid degradation of antibiotics

Co-based catalysts play a crucial role in the activation of peroxymonosulfate (PMS) for degradation contaminants. However, the practical application of such catalysts is hindered by challenges like the self-aggregation of Co nanoparticles and leaching of Co2+. In this study, the Co-based catalyst Co-N/C@CL was synthesized from carboxymethylated lignin obtained by grafting abundant carboxymethyl groups into alkali lignin, in which the presence of these carboxymethyl groups enhanced its water solubility and allowed the formation of stable macromolecular complexes with Co2+. This catalyst exhibited a high specific surface area (521.8 m2·g−1) and a uniform distribution of Co nanoparticles. Consequently, the Co-N/C@CL/PMS system could completely remove 20 ppm tetracycline (TC) in 2 min at a rate of 2.404 min−1. Experimental results and DFT calculations revealed that the synergistic effect of lignin carbon and Co NPs accelerated the cleavage and electron transfer of OO bonds, thus promoting the formation of 1O2, OH and SO4−, with 1O2 emerging as the predominant contributor. Moreover, Co-N/C@CL displayed excellent cycling stability and low Co2+ leaching. This work not only provides a feasible strategy for the preparation of highly active and stable Co-based carbon materials but also offers a promising catalyst for the efficient degradation of TC.

Preparation and characterization of carboxymethylated Aureobasidium pullulans β-(1 → 3, 1 → 6)-glucan and its in vitro antioxidant activity

Aureobasidium pullulans β-(1 → 3, 1 → 6)-glucan (APG) has a high degree of β-(1 → 6)-glucosyl branching and a regular triple helical structure similar to that of schizophyllan. In this study, APG was carboxymethylated to different degrees of substitution (DS = 0.51, 1.0, and 2.0, denoted CMAPG 1–3, respectively) using a heterogeneous reaction. With increasing DS, the triple-helix structure drastically decreased and converted to a random coil structure in CMAPG 3. Further, aqueous solutions of CMAPG changed from pseudoplastic fluids to perfect Newtonian liquids with increasing DS, indicating that the intra- and intermolecular hydrogen bonds had been cleaved by the substituents to form a random coil structure. In addition, APG and CMAPG solutions exhibited scavenging ability against hydroxyl, organic, and sulfate radicals. It was also found that the carboxymethylation of APG drastically enhanced the organic radical scavenging ability. On the basis of the relationship between the DS and radical scavenging ability of the CMAPG samples, we believe hydroxyl and organic radicals were preferably scavenged by the donation of hydrogen atoms from the glucose rings and the methylene moieties of the carboxymethyl groups, respectively. Considering the obtained results, CMAPG and APG are expected to have applications in pharmaceuticals, functional foods, and cosmetics as antioxidant polysaccharides.

Synthesized carboxymethyl-chitosan variant composites for cyclic adsorption-desorption based removal of Fe, Pb, and Cu

The global issue of environmental contamination from industrial wastewater comprising Cu, Fe and Pb demands effective treatment strategies. In this article, a functional composite sorbent was devised to selectively remove copper, iron, and lead from a real-world mimicking wastewater system. For the purpose, high, medium, and low molecular weight chitosan with amine and hydroxyl functional groups were used as a substrate, and glutaraldehyde was used to anchor the organic compound with carboxymethyl groups. Characterization with X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray analyzer accompanied by field emission scanning electron microscope, and Brunauer-Emmett-Teller were conducted for the synthesized adsorbent. Accordingly, the properties of the adsorbent were evaluated to infer that the synthesis assured a purified and functionalized system. The surface area of the medium carboxymethyl chitosan derivative was analyzed as 31.43 m2 g−1. Various adsorption parameters were examined methodically to assess upon optimal removal requirements. The effect of adsorbent dosage, contact time and concentration on the adsorption of the studied metal ions were conducted and the optimum values were achieved at pH 3.82, 540 min contact duration and 1.2 g L−1 sorbent dose. Maximum adsorbent capacities of 344.83 mg g−1, 9.59 mg g−1, and 90.09 mg g−1 were realized for Cu, Pb, and Fe, respectively. The experimental measurements of the studied heavy metal ions inferred the best fitness of Langmuir isotherm equilibrium and pseudo second order kinetic models. Further, elution studies with easy-to-deploy low-cost acidic and basic eluents (HCl, HNO3, H2SO4, KOH, and NaOH) were conducted with cyclic adsorption-desorption strategies. These investigations confirmed the adsorbent's good reusability up to 3 cycles of adsorption and its proximity to serve as a potential material for multi-heavy metal ions elimination from complex adsorbate systems.

Preparation, characteristics, and antioxidant activities of carboxymethylated polysaccharides from Paeonia x suffruticosa petals

Two carboxymethylated polysaccharides (CPSP30, CPSP60) were obtained from the petals of Paeonia x suffruticosa Andrews (PSP30, PSP60, respectively) with different molecular weight. Chemical characterization, morphological properties and antioxidant activities of PSP and CPSP were determined. PSP were mainly composed of galactose, glucose, fructose and galacturonic with different molar percentages. CPSP were mainly composed of arabinose, galactose, glucose with different molar percentages. The signals of carboxymethyl groups were found in Fourier transform infrared spectroscopy (FT-IR) and 13C nuclear magnetic resonance (NMR) spectra. Scanning electron microscopy (SEM) indicated that the original polysaccharides had a smooth surface, while the modified polysaccharides had an irregular lamellar structure. Thermal analysis indicated that the modified polysaccharides (CPSP30, CPSP60) presented higher thermal stability than the original polysaccharides. All polysaccharides presented typical structures of non-crystalline compounds. Carboxymethylation did not destroy the triple-helical structures of the polysaccharides. With its lower molecular weight, CPSP30 had higher scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH), OH, and Fe2+ chelating ability than PSP30. The scavenging DPPH and OH abilities of both derivatives were higher than that of original polysaccharides. This study demonstrates that carboxymethylation improved the solubilities and antioxidant abilities of the original polysaccharides, thus enhancing their potential for application in food and pharmaceutical industry.

Facile preparation of biocompatible and antibacterial water-soluble films using polyvinyl alcohol/carboxymethyl chitosan blend fibers via centrifugal spinning

Water-soluble polyvinyl alcohol/carboxymethyl chitosan (PVA/CMCS) blend fiber films were successfully prepared using a plane-collection centrifugal spinning machine. The addition of CMCS significantly increased the shear viscosity of the PVA/CMCS blend solution. The effects of spinning temperature on the shear viscosity and the centrifugal spinnability of PVA/CMCS blend solution were discussed. The PVA/CMCS blend fibers were uniform, and their average diameters ranged from 1.23 μm to 29.01 μm. It was found that the CMCS was distributed evenly in the PVA matrix and increased the crystallinity of PVA/CMCS blend fiber films. The hydrogen bonds between the hydroxyl group of PVA and the carboxymethyl group of CMCS were also detected. An in vitro cell study of human skin fibroblast cells on the PVA/CMCS blend fiber films confirmed biocompatibility. The maximum tensile strength and elongation at break of PVA/CMCS blend fiber films could reach 3.28 MPa and 29.52 %, respectively. The colony-plate-count tests indicated that the PVA16-CMCS2 presented 72.05 % and 21.36 % antibacterial rates against Staphylococcus aureus (104 CFU/mL) and Escherichia coli (103 CFU/mL), respectively. These values indicated that the newly prepared PVA/CMCS blend fiber films are promising materials for cosmetic and dermatological applications.

Genomic and structural basis for evolution of tropane alkaloid biosynthesis

The tropane alkaloids (TAs) cocaine and hyoscyamine have been used medicinally for thousands of years. To understand the evolutionary origins and trajectories of serial biosynthetic enzymes of TAs and especially the characteristic tropane skeletons, we generated the chromosome-level genome assemblies of cocaine-producing Erythroxylum novogranatense (Erythroxylaceae, rosids clade) and hyoscyamine-producing Anisodus acutangulus (Solanaceae, asterids clade). Comparative genomic and phylogenetic analysis suggested that the lack of spermidine synthase/N-methyltransferase (EnSPMT1) in ancestral asterids species contributed to the divergence of polyamine (spermidine or putrescine) methylation in cocaine and hyoscyamine biosynthesis. Molecular docking analysis and key site mutation experiments suggested that ecgonone synthases CYP81AN15 and CYP82M3 adopt different active-site architectures to biosynthesize the same product ecgonone from the same substrate in Erythroxylaceae and Solanaceae. Further synteny analysis showed different evolutionary origins and trajectories of CYP81AN15 and CYP82M3, particularly the emergence of CYP81AN15 through the neofunctionalization of ancient tandem duplication genes. The combination of structural biology and comparative genomic analysis revealed that ecgonone methyltransferase, which is responsible for the biosynthesis of characteristic 2-substituted carboxymethyl group in cocaine, evolved from the tandem copies of salicylic acid methyltransferase by the mutations of critical E216 and S153 residues. Overall, we provided strong evidence for the independent origins of serial TA biosynthetic enzymes on the genomic and structural level, underlying the chemotypic convergence of TAs in phylogenetically distant species.

Novel 4,4′-Binaphthalimidyl derivatives with carboxyalkyl side chains: Synthesis, Aggregation-induced emission, Hydrogel and Cell imaging

The introduction of aryl groups and/or alkyl side chains to the periphery of a conjugated skeleton can modulate the pattern of molecular aggregation in solution and facilitate its aggregation-induced emission (AIE) performance. In this study, novel three compounds of 4,4′-binaphthalimidyl derivatives (BNICn) were synthesized successfully in which two 1,8-naphthalimide (NI) units were connected by a rotatable single bond at their 4-sites, and two carboxyalkyl chains (number of carbon atoms in the carboxyalkyl chains (n) = 2, 6, and 11) were linked with the nitrogen atoms of NI. BNICn has weakly fluorescent in dilute solutions but become highly emissive in aggregate states. Interestingly, they exhibited carboxyalkyl-dependent AIE properties. The AIE performance of BNIC2 with the shortest carboxyalkyl chain is the strongest among those of the three compounds. The aggregation was also confirmed by the dynamic light scattering (DLS) tests. Moreover, the fluorescence intensities enhanced with the increasing viscosity of the solutions, verifying that the restriction of intramolecular motions (RIM) leads to the occurrence of AIE. Furthermore, the interactions such as π-π stacking of NI groups, and the intermolecular hydrogen-bonding of the carboxyl groups at the terminal of the side chains of BNICn was respectively verified by 1H NMR and FTIR. Thus, a possible self-assemble mode of BNICn is that the stacking NI segments of BNICn are located by the intermolecular hydrogen bonds of carboxyl groups at the terminal of the side chains of BNICn enacting an anchor-like role during aggregation process. For BNIC2 with carboxymethyl group, the shortest spacer of methylene group resulted in more effectively restriction for the intramolecular vibration and rotation, leading to a more efficient AIE performance. Meanwhile, BNIC11 can form thermal-reversible fluorescence hydrogel with ethylenediamine as well as BNIC2 can be applied in cellular imaging. Thus, an effective strategy to achieve and adjust the AIE performance of NI derivatives is proposed.

Evaluating the Impact of Cellulose Extraction via Traditional and Ionosolv Pretreatments from Domestic Matchstick Waste on the Properties of Carboxymethyl Cellulose.

Carboxymethyl cellulose (CMC) is a hydrophilic derivative of cellulose whose large volumes have been used in textile processing, protective coatings, detergents, papers, and drilling fluids, while cellulose gum, which is the purified form of CMC, has extensive applications in food, cosmetic, and pharmaceutical industries. Therefore, this work reflects the production of CMC by extracting cellulose with traditional and ionosolv methods from domestic matchstick waste, providing an in-depth view of the overall process where two different kinds of cellulose were obtained from two different pretreatments, and the influence of cellulose on the profile of CMC was checked. All of the procedures have been performed under optimized conditions to reduce the cost and maximize the productiveness. The results depict that cellulose extracted by the ionosolv method using a protic ionic liquid, tetramethylguanidinium hydrogen sulfate (TMG-HSO4), is more degraded than that extracted by the traditional sulfide method using sodium sulfide (Na2S) and sodium hydroxide (NaOH). Thus, the produced CMC-2 via ionic liquid-extracted cellulose has more yield, DS (2.3), purity (98.5%), and solubility with less salt and moisture contents than CMC-1 produced by the conventional method due to an effective substitution of the hydroxyl group by the carboxymethyl group. Further, instrumental analyses like FTIR, XRD, 1H NMR, 13C NMR, and SEM emphasize the results that CMC-2 has more reduction of the hydroxyl peak in FTIR, a more amorphous structure in XRD, intense peaks in NMR, and the roughness of the surface in SEM.

Comparative robustness and sustainability of in-situ prepared antimony nanoarchitectonics in chitosan/synthesized carboxymethyl chitosan in environmental remediation perspective

Due to the rapid race of industrialization natural assets like fresh water has been deteriorated causing lethal effects in living organisms. In the current study robust and sustainable composite of in-situ antimony nanoarchitectonics in chitosan/synthesized carboxymethyl chitosan matrix were synthesized. To improve solubility, metal adsorption and water decontamination, chitosan was modified into carboxymethyl chitosan and the modification was confirmed through various characterization techniques. The characteristic bands in the FTIR spectrum confirm substitution of carboxymethyl group in the chitosan. This was further illustrated that the characteristic proton peaks of CMCh observed at δ = 4.097 to 4.192 ppm, suggesting O-carboxy methylation of chitosan by 1H NMR. The second order derivative of potentiometric analysis confirmed 0.83 degree of substitution. The antimony (Sb) loaded modified chitosan were confirmed by FTIR and XRD analysis. The potential effectiveness of chitosan matrix was determined and compared toward reductive removal of the Rhodamine b dye. Rhodamine b mitigation is following first order kinetics with R2 value of 0.9832 and 0.969 with a constant rate of 0.0977 and 0.2534 ml/min for Sb loaded chitosan and carboxymethyl chitosan respectively. The Sb/CMCh-CFP enables us to achieve 98.5 % mitigation efficiency within 10 min. The CMCh-CFP chelating substrate was found stable and efficient even after 4th batches of cycles with <4 % decrease in efficiency. The in-situ synthesized material was found tailored composite, in terms of dyes remediation, reusability and biocompatibility as compared to chitosan.

Self-template activated carbons for aqueous supercapacitors

Activated carbons have been employed widely in aqueous supercapacitors due to their merits of large specific surface area (SSA), good electrical conductivity and chemical stability. However, toxic, corrosive and complicated activation processes hinder the further development of their industrialization. Here, we report a green and facile self-template activation strategy to synthesize hierarchical porous carbons as the electrode material for aqueous supercapacitors. Without pre-mixing procedures and additional activation processes, the hierarchical porous carbons can be obtained by one-step pyrolysis of sodium carboxymethylcellulose (CMCNa). This work reveals the dependence of aqueous capacitive performance on the pyrolysis temperature (PT), molecular weight (MW) and degree of substitution (DS, the number of hydroxyl groups substituted by sodium carboxymethyl groups on the monomeric anhydroglucose unit) of CMCNa. The results indicate that the DS is a more important factor because the obtained porosity is determined by the addition of the activating agent (Na2CO3) decomposed from sodium carboxymethyl groups. The optimized porous carbon pyrolyzed from CMC−Na with DS of 1.2 exhibits a large SSA of 1,274 m2 g−1 with a specific capacitance of 197 F g−1 at the current density of 0.5 A g−1 and 77% retaining capacitance even at 50 A g−1 in a three-electrode cell. The assembled aqueous coin cell shows no capacitance fading after 10,000 cycles at 5 A g−1 and possesses a higher energy density compared to commercial activated carbon. Hence, self-template activated carbons are promising candidates in the fabrication of high-performance aqueous supercapacitors.

Physicochemical and functional characterization of agave fructans modified by cationization and carboxymethylation

This work describes the cationization and carboxymethylation of agave fructans and their physicochemical and functional characterization. The results show that the modification gives rise to degrees of substitution of 0.487 and 0.133 for the carboxymethylated and cationic derivatives, respectively. FTIR, DSC and HPLC-SEC results demonstrated the incorporation of quaternary ammonium and carboxymethyl groups in the native fructan molecular structure. As a result of the structure modification, the increase in molecular weight, the appearance of new bands in the FTIR spectrum and changes in thermal properties were observed. The zeta potential demonstrated the anionic and cationic character of the modified fructans. There were no changes in the swelling capacity, however the cationic fructans have a higher oil holding capacity. Native and modified fructans exhibited antimicrobial effect against Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Salmonella enterica Typhimurium with higher antimicrobial activity against Gram negative microorganisms.

ANTIMICROBIAL APPROACHES FOR TEXTILES

The use of textile materials with antimicrobial treatment is one of the ways to effectively protect a person from exposure to various pathogens. The article is devoted to the topical issue of the development of innovative textile materials with prolonged antimicrobial treatment. To establish the possibility and features of obtaining innovative textile materials with long-term antimicrobial treatment. To prepare this article, many materials were considered, as well as ready-made solutions that were publicly available.Despite the fact that research on this topic was conducted, in order to obtain a prolonged effect, special attention needs to be paid to the problem of fixing the antimicrobial drug.To establish the technological features of applying a prolonged action antimicrobial treatment to textile material. The main tasks are to determine the composition of the composition and the peculiarities of the processing of the textile material; to investigate the influence of the polymer carrierand the fixing agent on the permanence of the final treatment and the stability of the antimicrobial effect.In order to obtain a prolonged antimicrobial effect, the problem of fixing the antimicrobial drug on the textile material was solved by using the developed preparation composition. The proposed finishing compound contains carboxymethylated starch, decamethoxine as a bactericidal drug and an agent for fixing them on the textile material -potassium iodide. The effect of the finishing components on the sorption of modified starch by cotton fabric was studied and a significant increase in its content on the fabric was revealed during simultaneous impregnation. The detected phenomenon is proposed to be explained by the formation of an ionic bond between carboxymethyl groups and decamethoxin. The technological features of applying a long-acting antimicrobial treatment to a textile material, which consists in the use of a one-stage technology, have been clarified.The influence of the polymer carrier and the fixing agent on the permanence of the final treatment and the stability of the antimicrobial effect is shown. The results of antimicrobial tests of prepared samples processed by various technological methods are presented. It was found that the fabric prepared according to the proposed technological regimes has an antimicrobial effect that is resistant to multiple washings. The developed technology is promising and can be implemented on the equipment of finishing factories

Production of Carboxymethylated Xanthan Gum Microemulsions for Eugenol Encapsulation

AbstractEugenol is a compound with well‐known bioactivity; however, its volatility limits its therapeutic applicability. In the present study, carboxymethylated xanthan gum (CXG) is synthesized and characterized regarding its degree of substitution (DS) by potentiometric titration and by infrared spectroscopy (FTIR). Oil‐in‐water xanthan gum‐based nanoemulsions enriched with eugenol have been prepared in variable conditions, using XG (xanthan gum) and CXG as matrices to produce a stable formulation with an effective ovicidal activity. Physical–chemical characterizations are performed, besides ovicidal activity on Haemonchus contortus, the main gastrointestinal nematode infecting and affecting small ruminants. FTIR results indicate the insertion of the carboxymethyl groups in the structure of xanthan gum through the peaks at 1100 and 1600 cm−1, and titration shows a DS of 1.25 for CXG. XG and CXG emulsions present stability over 30 days and encapsulation efficiency higher than 50%. The CXG2 emulsion (CXG:oil:tween 4:2:1) shows better stability concerning the lower zeta potential value, and the morphology shows domains with smaller sizes in the range of 1.41 µm. The evaluated nanoemulsions show ovicidal activity against H. contortus, which encourages their future use as an alternative to control haemonchosis in sheep and goats.

Carboxymethyl tethered poly(disubstituted)triazoles built on nucleoside skeletons: A unique class of ribonuclease A inhibitors designed using chemical logic

Molecular docking of N-1,4-disubstituted-1,2,3-triazole tethered carboxymethylated thymidine and uridine with ribonuclease A, indicated their possible binding with the P1, B1 and P2 subsites with varied efficiencies. This theoretical study in combination of our earlier experimental observations was used as the guiding principles for designing a range of 1,4-disubstituted 1, 2, 3- triazole tethered carboxymethylated pyrimidine nucleosides. Triazoles are biologically important molecules and at the same time easily accessible through less complicated synthetic routes as reported about two decades back in the context of “click” reactions. Regioselective propargylation of the nucleosides under controlled conditions followed by the use of CuAAC strategy afforded mono-, bis-, tris- and tetratriazolyl pyrimidine nucleosides. Although the characteristics of nucleosides were lost in these densely functionalized polyheterocycles, the catalytic efficiency of ribonuclease A was significantly reduced by these molecules which were investigated experimentally and by docking studies. Triazoles as linkers helped one or more acidic groups to reach the P1 subsite of ribonuclease A. Enzyme kinetics showed that the efficiency of inhibition reached the highest point with an optimum number of functional groups and were not linearly dependent on the number of triazole tethered carboxymethyl groups. The location of the triazole ring in the molecule affected the efficiency and nature of inhibition which were the result of the overall structure of the modified nucleosides. Thus, the tris-triazolylated thymidine derivative (T-3′, 5′, N-tris-CH2TzCH2COOH) as opposed to tetra-triazolylated uridine (U-2′, 3′, 5′, N-tetrakis-CH2TzCH2COOH) emerged as the best inhibitor with an inhibition constant value of 2.3 ± 0.05 µM.

Bisulfite-Free and Single-Base Resolution Detection of Epigenetic DNA Modification of 5-Methylcytosine by Methyltransferase-Directed Labeling with APOBEC3A Deamination Sequencing.

DNA methylation (5-methylcytosine, 5mC) is the most prevalent epigenetic modification that is predominantly found in CG dinucleotides in mammalian genomes. In-depth investigation of the functions of 5mC heavily relies on the quantitative measurement of 5mC at single-base resolution in genomes. Here, we proposed a methyltransferase-directed labeling with APOBEC3A (A3A) deamination sequencing (MLAD-seq) method for the single-base resolution and quantitative detection of 5mC in DNA. In MLAD-seq, a mutant of DNA methyltransferase, M.MpeI-N374K, is utilized to selectively transfer a carboxymethyl group to the 5 position of cytosine in the CG dinucleotide to form 5-carboxymethylcytosine (5camC) using carboxy-S-adenosyl-l-methionine (caSAM) as the cofactor. After A3A treatment, 5camC is resistant to the deamination and base pairs with guanine. Thus, the cytosines in CG sites are read as C in sequencing. On the contrary, the methyl group in 5mC inhibits its carboxymethylcytosine by M.MpeI-N374K and therefore is readily deaminated by A3A to produce thymine that pairs with adenine and is read as T in sequencing. The differential readouts from C and 5mC in the MLAD-seq enable the single-base resolution mapping of 5mC in CG sites in DNA. With the developed MLAD-seq method, we observed the hypermethylation in the promoter region of retinoic acid receptor β (RARB) gene from human nonsmall cell lung tumor tissue. Compared to harsh reaction conditions in bisulfite sequencing that could lead to significant degradation of DNA, the whole procedure of MLAD-seq is carried out under mild conditions, which will avoid DNA damage. Thus, MLAD-seq is more suitable in the scenario where only limited input DNA is available. Taken together, the MLAD-seq offers a valuable tool for bisulfite-free, single-base resolution and quantitative detection of 5mC in limited DNA.

Multifunctional carboxymethyl cellulose sodium encapsulated phosphorus-enriched biochar composites: Multistage adsorption of heavy metals and controllable release of soil fertilization

Water and soil heavy metal contamination induced by wastewater irrigation endanger human health. To improve the long-term heavy metal removal performance in the complicated aqueous/soil system, a novel carboxymethyl cellulose sodium (CMC-Na) encapsulated phosphorus (P)-enriched biochar (CMC@MBC) was synthesized. The maximum adsorption capacities of the unmodified biochar for Pb(II), Cd(II), and Ni(II) were increased by 822, 464, and 256 mg/g, respectively. The CMC-Na encapsulation introduced abundant carboxymethyl groups and enables CMC@MBC a strong anti-pH interference ability. The sewage treatment result revealed that CMC@MBC functioned admirably with prolonged sewage flushing. The long-term effectiveness of CMC@MBC against heavy metals might be explained by a multistage adsorption process: immediate adsorption by the CMC-Na coating, fast adsorption at the interface of CMC-Na and P-enriched biochar (MBC), and delayed adsorption by the P compound progressively released from MBC. Heavy metal speciation analysis indicates that the contributions of different adsorption mechanisms vary with heavy metals. The macromolecular spatial network structure of CMC-Na could be a good cover for preventing P leaching, making CMC@MBC a great slow-release fertilizer (SRF) with a cumulative P release ratio of 61 % after 28 days of application. This work suggests that CMC@MBC is a low-cost and high-efficiency adsorbent and phosphorus SRF.

The formation of silver nanoparticles in solutions of sodium salts of carboxymethyl starch

The possibility of obtaining a biodegradable bactericidal composition containing silver nanoparticles by the reduction of silver ions using sodium carboxymethyl starch and UV irradiation has been investigated in this work. It is shown that the degree increase of substitution of carboxymethyl groups in NaCMS leads to an intensity increase of absorption of the surface plasma resonance bands of AgNP and an intensification of the Ag+ reduction process to Ag0. The intensity of the emerging Ag peak shows a complete reduction of Ag+ to Ag0 and the effectiveness of CMS in stabilizing the resulting AgNP. The results obtained from the EDX spectrum, together with the results of the SEM images, are strong evidence for the formation of AgNP nanoparticles and indicate the long-term colloidal stability of the product. It is shown that the processed nanocomposite solution AgCMS hosiery and non-woven materials have high antibacterial activity.