Presence Of Methylation Research Articles

Simultaneous Determination of Active Ingredients in Multicomponent Common Over the Counter Tablets in the Present of Parabens and 4-Aminophenol by HPLC

A new selective reverse-phase high-performance liquid chromatography method with an attitude of practical use in pharmaceutical laboratories for simultaneous determination of Ascorbic acid, Acetaminophen, phenylephrine, Caffeine, Pamabrom, Guaifenesin, Dextromethorphan, Pyrilamine, Chlorpheniramine maleate, Ibuprofen in the presence of Methyl, Ethyl, Butyl Parabens as preservatives has been developed and validated. These active pharmaceutical ingredients widely used in a variety of cough and cold medicines. The separation was carried out on an Atlantis dC18 column including 4.6 mm inner diameter, 150 mm length and particle size of 3 μm, using a mobile phase which consisted of an ion-pairing agent (sodium salt of heptane sulphonic acid) as a buffer solution mixed with acetonitrile as an organic modifier at a flow rate of 1 mL min−1 on a gradient system. The investigation was carried out on wavelength program detection to quantify the very low concentration of Dextromethorphan and Chlorpheniramine and high concentration of Acetaminophen, Guaifenesin, Ibuprofen, Ascorbic Acid at the wavelengths of 290 and 215 nm. The temperature was maintained at 40 °C. The method was shown to be linear (R2 > 0.996), accurate (recoveries 97.77–103.94%), precise (RSD ≤ 1.0%), sensitive, specific, simple, fast and robust. The proposed reverse phase-liquid chromatography method was successfully applied to the routine analysis of the Over-The-Counter tablets containing these active pharmaceutical ingredients without any interference with excipients and parabens and 4-aminophenol.

Structures and dynamics of DNA complexes of the desmethyl analog of the cytotoxin MLN944: Insights into activity when a methyl isn't futile.

Structure activity relationships for tricyclic-carboxamide topoisomerase II poisons indicate that cytotoxicity is enhanced by the presence of methyl, and other, groups in the position peri to the carboxamide. Linked dimers of phenazine-1-carboxamides are potent cytotoxins and one phenazine dimer, MLN944 (alternatively XR5944), has been in clinical trial. MLN944 is a template inhibitor of transcription, whereas corresponding monomers are not. Nevertheless, its cytotoxic potency is also diminished by removal of its peri methyl groups. Here, we describe NMR and molecular dynamic studies of the interaction of desmethyl MLN944 with d(ATGCAT)2 , d(TATGCATA)2 , and d(TACGCGTA)2 to investigate the influence of the nine-methyl group on the structure of MLN944 complexes. As with MLN944, the carboxamide group hydrogen bonds to the phenazine ring nitrogen, the ligand sandwiches the central GC base pairs in the major groove, and the protonated linker amines hydrogen bond primarily to the O6 atom of the guanines. Molecular dynamics studies reveal that the linker exists in multiple conformations, none of which produce an ideal set of hydrogen bonds. In distinction, however, the carboxamide-to-phenazine ring nitrogen hydrogen bond is weaker, the overall helix winding is less and the NMR resonances are broader in the desmethyl complexes. Exchange between free and complexed DNA, quantified using two-dimensional NOESY spectra, is faster for the desmethyl MLN944 complexes than for MLN944 complexes. Overall, the data suggest that desmethyl MLN944 DNA complexes are "looser" and more unwound at the binding site, leading to faster dissociation rates, which could account for the diminished efficacy of the desmethyl analog.

Methylation Pattern of the SOCS3 and IL6R Promoters in Rheumatoid Arthritis.

Interleukin-6 (IL-6) plays an essential function in the development of rheumatoid arthritis (RA), mainly through its proinflammatory effect, which may lead to joint destruction. The genes encoding IL-6 receptor (IL6R) and suppressor of cytokine signaling 3 (SOCS3) play a key role in the IL-6 signaling pathway, but their epigenetic regulation remains unclear. The aim of the study was to investigate how the presence of methylation in the SOCS3 and IL6R promoters is associated with the morbidity and severity of RA. A total of 146 unrelated individuals, 122 with RA and 24 healthy controls, were enrolled in the study. All subjects were genotyped with regard to the rs4969168 and rs4969170 polymorphisms in the SOCS3 gene and the rs2228145 and rs4129267 polymorphisms in IL6R. The methylation study included 52 patients with RA and 24 healthy controls. Qualitative real-time methylation-specific PCR was used to evaluate methylation status. We found no differences between patients and healthy controls in the methylation pattern in the IL6R and SOCS3 promoter regions and in variants frequency. The methylation profiles of the SOCS3 and IL6R promoters do not support the hypothesis that the genes SOCS3 and IL6R involved in the JAK-STAT signaling pathway are epigenetically deregulated in whole blood.

Green, catalyst-free, facile and one pot electrochemical synthesis of new bis-indoles from p- phenylenediamine oxidation in the presence of cyanoacetate derivatives

Electrochemical oxidation of p - phenylenediamine has been investigated in the presence of methyl and ethyl cyanoacetate as a nucleophile in phosphate buffer solution mixed with ethanol (10/90 v/v) using cyclic voltammetry and controlled-potential coulometry methods. The results revealed that cyclohexa-2,5-diene-1,4-diimine derived from electro-oxidation of p - phenylenediamine participates in 1,4-Michael addition reactions with cyanoacetate derivatives. The formed adducts convert to the corresponding bis-indole derivatives via ECECCC (Electrochemical, chemical, chemical reactions) mechanism. In the present work, new bis-indoles were synthesized with high purity and good yields using controlled potential electrochemical oxidation at five graphite electrode in an undivided cell under mild conditions.

One-pot synthesis of tetraarylpyrrolo[3,2-b]pyrrole dopant-free hole-transport materials for inverted perovskite solar cells

Four organic small-molecule hole transport materials (D41, D42, D43 and D44) of tetraarylpyrrolo[3,2-b]pyrroles were prepared. They can be used without doping in the manufacture of the inverted planar perovskite solar cells. Tetraarylpyrrolo[3,2-b]pyrroles are accessible for one-pot synthesis. D42, D43 and D44 possess acceptor-π-donor-π-acceptor structure, on which the aryl bearing substitutes of cyan, fluorine and trifluoromethyl, respectively. Instead, the aryl moiety of D41 is in presence of methyl with a donor-π-donor-π-donor structure. The different substitutes significantly affected their molecular surface charge distribution and thin-film morphology, attributing to the electron-rich properties of fused pyrrole ring. The size of perovskite crystalline growth particles is affected by different molecular structures, and the electron-withdrawing cyan group of D42 is most conducive to the formation of large perovskite grains. The D42 fabricated devices with power conversion efficiency of 17.3% and retained 55% of the initial photoelectric conversion efficiency after 22 days in dark condition. The pyrrolo[3,2-b]pyrrole is efficient electron-donating moiety for hole transporting materials to form good substrate in producing perovskite thin film.

Genetic and epigenetic modifications of adiponectin gene: Potential association with breast cancer risk.

Adipokines produced by adipose tissue are directly linked to obesity and may contribute to the pathogenesis of cancer. We hypothesized that genetic and epigenetic modifications in the adiponectin (ADIPOQ) gene and their impact on serum ADIPOQ levels may participate in increasing breast cancer (BC) risk. The present study aimed to investigate ADIPOQ+45 T/G gene polymorphism, methylation status at CpG sites -74nucleotides (nt) and -283nt of the ADIPOQ gene, and ADIPOQ serum levels in BC obese women. Serum ADIPOQ was measured by an enzyme-linked immunosorbent assay. ADIPOQ+45 T/G gene polymorphism and ADIPOQ promoter methylation status were determined using a polymerase chain reaction (PCR) and a methylation-specific PCR, respectively, in 120 obese women with BC and 120 age-matched controls. ADIPOQ+45 GG genotype carriers had a significant increased risk of developing BC (odds ratio=6.2, 95% confidence interval=1.3-29.6, p=0.02). ADIPOQ gene methylation at site -74 nt resulted in a 1.7-fold increased BC risk. Methylation at site -283 nt resulted in a 1.9-fold increased BC risk. Moreover serum levels of ADIPOQ were significantly decreased in BC patients and down-regulated in the presence of methylation in both examined sites. By contrast, no association between ADIPOQ gene polymorphism and serum ADIPOQ level was detected. Using both methylated sites in one panel detected cancer breast with 76.67% sensitivity and 62.18% accuracy. ADIPOQ+45 T/G polymorphism and ADIPOQ promoter methylation were found to be associated with BC risk in obese Egyptian women.

Identification of methylation-driven genes related to prognosis in clear-cell renal cell carcinoma.

With the participation of the existing treatment methods, the prognosis of advanced clear‐cell renal cell carcinoma (ccRCC) is poor. More evidence indicates the presence of methylation in ccRCC cancer cells, but there is a lack of studies on methylation‐driven genes in ccRCC. We analyzed the open data of ccRCC in The Cancer Genome Atlas database to obtain ccRCC‐related methylation‐driven genes, and then carried out pathway enrichment, survival, and joint survival analyses. More important, we deeply explored the correlation between differential methylation sites and the expression of these driving genes. Finally, we screened 29 methylation‐driven genes via MethylMix, of which six were significantly associated with the survival of ccRCC patients. This study demonstrated that the effect of hypermethylation or hypomethylation on prognosis is different, and the level of methylation of key methylation sites is associated with gene expression. We identified methylation‐driven genes independently predicting prognosis in ccRCC, which offers theoretical support in bioinformatics for the study of methylation in ccRCC and a new perspective for the epigenetic study of ccRCC.

IRF5 promoter methylation as a new potential marker of rheumatoid arthritis.

Introduction: The interferon regulatory factor 5 (IRF5) gene is implicated in the toll‑like receptor signaling pathway and has proinflammatory and chemotactic effects, but its role in the pathogenesis of rheumatoid arthritis (RA) remains unclear. Since the pathobiology of RA shares some similarities with other autoimmune diseases, we tested the hypothesis that RA may be associated with IRF5‑related pathways, as has been reported for systemic lupus erythematosus and Sjögren syndrome. Objectives: The aim of the study was to investigate the association between the presence of methylation in the IRF5 promoter and the morbidity and severity of RA as well as with levels of inflammatory markers. Patients and methods: A total of 146 unrelated individuals, 122 patients with RA and 24 healthy controls, were enrolled in the study. All RA patients were genotyped with regard to the following polymorphisms in the IRF5 gene: rs10488631, T>C and rs4728142 G>A. The methylation analysis included 52 patients with RA and 24 healthy controls. A quantitative real‑time methylation‑specific polymerase chain reaction was used to evaluate methylation status. Results: We found differences between patients with RA and healthy controls in the methylation pattern of the promoter region. The methylation level was 43.6% lower in RA patients than in controls (median [interquartile range], 0.79 [0.6-1.13] vs 1.4 [1.16-1.66]; P = 0.0001). Variant rs4728142 G>A was more common in seronegative patients with RA. Conclusions: The methylation profile of the IRF5 promoter may be used as a new potential marker of RA, which is independent of current criteria of disease activity.

Analysis of DNA Methylation Profile in Plants by Chop-PCR.

Plants, when challenged with any unfavorable condition, such as biotic or abiotic stress, adapt to the stress via physiological or structural changes. DNA methylation, an important epigenetic factor, plays an integral role in determining chromatin dynamicity and in turn regulates the process of gene transcription in eukaryotes. DNA methylation resulting in 5-methylcytosine interferes with the transcription process by hindering accessibility of the transcriptional machinery. Transcriptionally active genes are predominantly hypomethylated, whereas repressed genes exhibit hypermethylation. It can thus be interpreted that the presence of methylation in the promoter and upstream regions of loci represses their transcription and vice versa. Chop-PCR is a targeted DNA methylation detection technique that uses partial digestion by methylation-sensitive restriction enzymes (MSREs) followed by PCR amplification. The presence of cytosine methylation at the cleavage sites of the MSREs protects the DNA against digestion and therefore can be amplified using PCR. Enzymatic cleavage occurs unhindered at unmethylated restriction sites and subsequent PCR amplification of the target sequence is not observed.

Evaluation of parabens and their metabolites in fish and fish products: a comprehensive analytical approach using LC-HRMS

ABSTRACTParabens (PBs) are preservatives frequently used in cosmetics and personal care products as well as in the pharmaceutical and food industries due to their extensive defence mechanisms against multiple categories of microorganisms. Although they are considered safe when used within defined concentration limits, concern about their potential toxicity is still particularly active. Revealed as emerging pollutants, their incidence and behaviour in the aquatic environment have been studied, but there is only sporadic information when it comes to their extent and distribution in seafood. This study explores the presence of methyl- (MeP), ethyl-, propyl-, butyl-, and benzylparaben and their main degradation product 4-hydroxybenzoic acid (pHBA) in several fish species and bivalve samples with the aim to evaluate these food matrices as potentially important contamination sources of PB. Additionally, infant food containing fish was also enrolled in this survey: firstly, due to the absence of any information regarding this exceptionally important food item, and secondly, because of the necessity to estimate the PB content in the processed food. For this purpose, a fast, reliable and robust method was developed based on a simple liquid–liquid extraction followed by high-performance LC, coupled with a benchtop Q-Exactive Orbitrap high-resolution MS. The Q-Exactive parameters were carefully scheduled to achieve a balance between the optimal scan speed and selectivity, considering the limitations that are associated with generic sample preparation methodology. The method was validated through specificity, linearity, recovery, intra- and inter-day repeatability, LOD and LOQ. LOD and LOQ reached the ranges 0.65–3.5 and 2.15–11.7 ng g−1, respectively, while overall recovery ranged from 77% to 118%. The PBs were more frequently present in bivalves than in fish samples with MeP as the main PB detected. No PBs were found in infant food, but pHBA was observed in all samples.

Biodegradation of typical pharmaceutical compounds by a novel strain Acinetobacter sp.

A novel sulfamethoxazole (SMX)-degrading strain, Acinetobacter sp., was used to degrade other pharmaceutical compounds, including sulfadiazine (SD), sulfamethazine (SMT), trimethoprim (THM), triclosan (TCS), diclofenac (DFC) and carbamazepine (CBZ). The experimental results showed that Acinetobacter sp. can completely degrade SMX, SD and SMT, but with different mineralization efficiency. Acinetobacter sp. can mineralize 98.8% of SMX, while only 17.5% and 20.5% for SD and SMT, respectively. The intermediate products of SMX, SD and SMT degradation were tentatively identified. Based on the intermediates, it is inferred that the initial step for degrading sulfonamides by Acinetobacter sp. was the amidation of the amino groups in the benzene ring. The presence of methyl in the heterocyclic ring could induce the formation of methylase. By comparing the intermediates of SMX, SD and SMT degradation, it is concluded that Acinetobacter sp. preferred attacking the oxazole ring. However, Acinetobacter sp. cannot degrade THM, TCS, DFC and CBZ, while Acinetobacter sp. can still degrade SMX in the respective presence of THM, DFC and CBZ, although the degradation rate decreased. Moreover, the presence of TCS could completely inhibit the degradation of SMX by Acinetobacter sp.

136 DNA Methylation Status and Transcript Profile of Genes Associated with Lipid Metabolism, Cell Survival, and Pluripotency in Bovine Blastocysts with Different Kinetics of Development

During in vitro production (IVP), blastocysts can be differentiated based on the kinetics of early cleavage. These groups present distinct patterns of global DNA methylation, an epigenetic characteristic generally responsible for suppression (presence of methylation) or activation (absence of methylation) of genes from different biological pathways. This work investigated the DNA methylation and mRNA levels of genes related to embryo development and viability. For this purpose, bovine embryos underwent IVP using conventional protocols. After 40 h of insemination, embryos were classified as FBL (fast cleavage: 4 cells or more) or SBL (slow cleavage: 2 or 3 cells), remaining in culture until blastocyst stage. Sexed semen was used to prevent differences due to sex, even without statistical differences in male:female ratio already reported. Blastocysts (40 per group) were analysed by EmbryoGENE Methylation DNA Array (Ispada et al. 2016 Proc. 49th SSR: 181) and later analysed through BioMark™HD (Fluidigm Corp., South San Francisco, CA, USA) for the transcripts profile. The PPIA gene was used as endogenous control for ΔCt calculation and submitted to Student’s t-test. Genome-wide DNA methylation analysis identified 47,713 methylated regions (7976 hypermethylated in FBL and 3608 hypermethylated in SBL). Fast embryos presented more hypermethylations distributed throughout the genome, such as introns, exons, promoter and repeat elements, whereas hypermethylation were more present in CpG islands in slow embryos. Differentially methylated regions were clustered by means of biological processes and the most affected pathways were related to lipid metabolism and cell differentiation and survival. Regarding the gene expression analysis, all results are presented in FBL in relation to SBL. Of genes involved in lipid metabolism, ACSL3, ELOVL6, PPARA, and FADS, previously identified as hypermethylated genes, were down-regulated, whereas PPARG and PTGS2 showed no statistical difference; SCD and FASN, although hypomethylated, were also down-regulated, and ACSL6, which did not differ in DNA methylation status, was down-regulated. Of genes involved in survival/death, BAX, HSPA1A, BID, NFE2L2, and GPX1 were hypermethylated; however, the first 2 were up-regulated, BID was down-regulated, and the last 2 were not statistically different. Although CASP9, TXNRD1, and FOXO3 were all hypomethylated, only CASP9 was up-regulated. Also, DDIT3 was down-regulated and NOS2 was up-regulated, although they did not differ in DNA methylation between groups. Of genes involved in cell differentiation, POU5F1 and SALL4 were both hypermethylated, but only the POU5F1 was down-regulated; NANOG, which did not differ in DNA methylation status between groups, was also down-regulated. In conclusion, although we did not find correlation in DNA methylation and RNA levels for all genes evaluated, the chosen pathways were indeed different between groups, which could lead to their potential suppression/activation and affect embryo viability. Also, this lower correlation may be a result of the influence of other epigenetic mechanisms differently activated between groups.

Synergistic extraction of nickel(II) from a sulfate medium by a mixture of N-(2-hydroxybenzylidene)aniline and methyl–isobutyl ketone

ABSTRACTThe synergistic solvent extraction of nickel(II) from a sulfate medium with N-(2-hydroxybenzylidene)aniline in the absence and presence of Methyl–Isobutyl Ketone (MIBK) in chloroform at 25°C has been studied. A synergistic effect is observed for the metal at low and high (MIBK) concentration ratios, respectively. The synergistic extraction of nickel(II) with the mixtures has been investigated with the analysis methods of slope. The extractable species has been identified as NiL2 and NiL2(MIBK)2. The extraction constants are reported.

Synthesis and Characterization of Novel Heat Resistant, Superparamagnetic Poly(ether-imide) Nanocomposites Containing Xanthene: Representing a Strategy for Improving Thermal Stability of Magnetic Polymer-Based Nanocomposites

Two superparamagnetic and heat resistant xanthene based poly(ether-imide) nanocomposites were successfully synthesized. Field emission scanning electron microscopy, transmission electron microscope, X-ray diffraction, thermal gravimetric analysis, vibrating sample magnetometer, Energy-dispersive X-ray spectroscopy and Fourier-transform infrared (FTIR) techniques were used for studying the morphology, crystalline phase, thermal stability and magnetization properties of the nanocomposites. The neat form of the corresponding poly(ether-imide) was also prepared by thermal imidization method and its structure was confirmed by FTIR, proton nuclear magnetic resonance (1H NMR), UV–Vis and photoluminescence (PL) spectroscopies. In order to investigate the effects of modifying the surface of Fe3O4 nanoparticles on thermal properties of the nanocomposites, the surface of Fe3O4 nanoparticles was coated with SiO2 and polysuccinimide (PSI), sequentially. Then, both the unmodified Fe3O4 and surface-modified Fe3O4 (Fe3O4@SiO2–PSI) nanoparticles were used as fillers for the polymer matrix. According to the results, the prepared nanocomposites were superparamagnetic and showed higher thermal stability in comparison to the neat poly(ether-imide). Furthermore, poly(ether-imide)/Fe3O4@SiO2–PSI (PIEN 10b) nanocomposite showed higher thermal stability and dispersed better in the polymer matrix [in comparison to poly(ether-imide)/Fe3O4 (PIEN 10 a)] due to the presence of imide groups and high hydroxyl content of the functional Fe3O4 nanoparticles which caused high interactions between poly(ether-imide) and functional Fe3O4. Furthermore, the presence of methyl, ether and bulky xanthene groups in the poly(ether-imide(backbone improved the solubility of the neat polymer in organic solvents. These properties can be very helpful for extending new applications of poly(ether-imide)s.

Layer-by-Layer Engineered Microbicide Drug Delivery System Targeting HIV-1 gp120: Physicochemical and Biological Properties.

The purpose of this study was to engineer a model anti-HIV microbicide (tenofovir) drug delivery system targeting HIV-1 envelope glycoprotein gp120 (HIV-1 g120) for the prevention of HIV sexual transmission. HIV-1 g120 and mannose responsive particles (MRP) were prepared through the layer-by-layer coating of calcium carbonate (CaCO3) with concanavalin A (Con A) and glycogen. MRP average particle size ranged from 881.7 ± 15.45 nm to 1130 ± 15.72 nm, depending on the number of Con A layers. Tenofovir encapsulation efficiency in CaCO3 was 74.4% with drug loading of 16.3% (w/w). MRP was non-cytotoxic to Lactobacillus crispatus, human vaginal keratinocytes (VK2), and murine macrophage RAW 264.7 cells and did not induce any significant proinflammatory nitric oxide release. Overall, compared to control, no statistically significant increase in proinflammatory cytokine IL-1α, IL-1β, IL-6, MKC, IL-7, and interferon-γ-inducible protein 10 (IP10) levels was observed. Drug release profiles in the presence of methyl α-d-mannopyranoside and recombinant HIV-1 envelope glycoprotein gp120 followed Hixson-Crowell and Hopfenberg kinetic models, indicative of a surface-eroding system. The one Con A layer containing system was found to be the most sensitive (∼2-fold increase in drug release vs control SFS:VFS) at the lowest HIV gp120 concentration tested (25 μg/mL). Percent mucoadhesion, tested ex vivo on porcine vaginal tissue, ranged from 10% to 21%, depending on the number of Con A layers in the formulation. Collectively, these data suggested that the proposed HIV-1 g120 targeting, using MRP, potentially represent a safe and effective template for vaginal microbicide drug delivery, if future preclinical studies are conclusive.

Synthesis, experimental and theoretical vibrational studies of 1-methyl and 1,2-dimethyl, 3-propyl imidazolium bis(trifluoromethanesulfonyl) imide

In this study, two ionic liquids containing the bis(trifluoromethanesulfonyl)imide ( $$[(\hbox {CF}_{3}\hbox {SO}_{2})_{2}\hbox {N}^{-}]$$ ) anion are synthesized. The syntheses are based on an alkylation reaction of 1-methyl imidazole and 1,2-dimethyl imidazole followed by anion exchange. The obtained ILs are characterized by $$^{1}\hbox {H-NMR}$$ , $$^{13}\hbox {C-NMR}$$ , $$^{19}\hbox {F-NMR}$$ and FT-IR spectroscopy. Vibrational spectroscopy studies were conducted by infrared (FTIR/ATR), Raman spectroscopy and DFT calculations. The presence of methylation in the C2 position gives rise to specific marker bands in the Raman and IR spectra. In order to ascertain whether cation conformers are present in our ionic liquids, a computational study was performed using the density functional theory. The comparison of the experimental data and the computed spectra shows that three conformers of the imidazolium ions are present in both ionic liquids. Synopsis We synthesized and investigated the vibrational properties of two ionic liquids, namely, 1-methyl,3-propyl imidazolium bis(trifluoromethane-sulfonyl) imide ( $$[1\hbox {-MPrIM}^{+}][(\hbox {CF}_{3}\hbox {SO}_{2})_{2}\hbox {N}^{-}]$$ ) and 1,2-dimethyl,3-propyl imidazolium bis(trifluoromethane-sulfonyl) imide ( $$[1,2\hbox {-DMPrIM}^{+}][(\hbox {CF}_{3}\hbox {SO}_{2})_{2}\hbox {N}^{-}]$$ ). Methylation in the C2 position gives rise to specific marker bands in the Raman and IR spectra. The comparison of the experimental data and the computed spectra at DFT level shows that three conformers of the imidazolium ions are present in both ionic liquids.

The elephant shark methylome reveals conservation of epigenetic regulation across jawed vertebrates

Background: Methylation of CG dinucleotides constitutes a critical system of epigenetic memory in bony vertebrates, where it modulates gene expression and suppresses transposon activity. The genomes of studied vertebrates are pervasively hypermethylated, with the exception of regulatory elements such as transcription start sites (TSSs), where the presence of methylation is associated with gene silencing. This system is not found in the sparsely methylated genomes of invertebrates, and establishing how it arose during early vertebrate evolution is impeded by a paucity of epigenetic data from basal vertebrates. Methods: We perform whole-genome bisulfite sequencing to generate the first genome-wide methylation profiles of a cartilaginous fish, the elephant shark Callorhinchus milii. Employing these to determine the elephant shark methylome structure and its relationship with expression, we compare this with higher vertebrates and an invertebrate chordate using published methylation and transcriptome data. Results: Like higher vertebrates, the majority of elephant shark CG sites are highly methylated, and methylation is abundant across the genome rather than patterned in the mosaic configuration of invertebrates. This global hypermethylation includes transposable elements and the bodies of genes at all expression levels. Significantly, we document an inverse relationship between TSS methylation and expression in the elephant shark, supporting the presence of the repressive regulatory architecture shared by higher vertebrates. Conclusions: Our demonstration that methylation patterns in a cartilaginous fish are characteristic of higher vertebrates imply the conservation of this epigenetic modification system across jawed vertebrates separated by 465 million years of evolution. In addition, these findings position the elephant shark as a valuable model to explore the evolutionary history and function of vertebrate methylation.

The elephant shark methylome reveals conservation of epigenetic regulation across jawed vertebrates.

Methylation of CG dinucleotides constitutes a critical system of epigenetic memory in bony vertebrates, where it modulates gene expression and suppresses transposon activity. The genomes of studied vertebrates are pervasively hypermethylated, with the exception of regulatory elements such as transcription start sites (TSSs), where the presence of methylation is associated with gene silencing. This system is not found in the sparsely methylated genomes of invertebrates, and establishing how it arose during early vertebrate evolution is impeded by a paucity of epigenetic data from basal vertebrates. We perform whole-genome bisulfite sequencing to generate the first genome-wide methylation profiles of a cartilaginous fish, the elephant shark Callorhinchus milii. Employing these to determine the elephant shark methylome structure and its relationship with expression, we compare this with higher vertebrates and an invertebrate chordate using published methylation and transcriptome data. Results:Like higher vertebrates, the majority of elephant shark CG sites are highly methylated, and methylation is abundant across the genome rather than patterned in the mosaic configuration of invertebrates. This global hypermethylation includes transposable elements and the bodies of genes at all expression levels. Significantly, we document an inverse relationship between TSS methylation and expression in the elephant shark, supporting the presence of the repressive regulatory architecture shared by higher vertebrates. Our demonstration that methylation patterns in a cartilaginous fish are characteristic of higher vertebrates imply the conservation of this epigenetic modification system across jawed vertebrates separated by 465 million years of evolution. In addition, these findings position the elephant shark as a valuable model to explore the evolutionary history and function of vertebrate methylation.

Investigation of the Profile and Kinetics of Degradation of Fenticonazole Nitrate using Stability-indicating HPLC Assay in Presence of Methyl and Propyl Parabens: Application to Preformulation Studies

Fenticonazole (FEN), an imidazole group containing antifungal was subjected to stress conditions; acid and base hydrolysis, photodegradation, thermal decomposition and oxidation. The structure of one major oxidative degradation product was ellucidated using LC-MS/MS.A stability-indicating HPLC assay was developed and validated according to ICH guidelines which enabled the determination of FEN in presence of its degradation product and paraben preservatives (methyl and propyl parabens). Determination was carried out using Zorbax RP-C18-column (5 μm, 15 cm x 4.6 mm i.d.) and gradient elution mode over a concentration range of 10.00-200.00 μg mL-1, 3.50-35.00 μg mL-1 and 1.75-7.50 μg mL-1 for FEN, methyl paraben and propyl paraben, respectively. Column temperature was maintained at 25°C and detection was carried out at 254 nm. As confirmed by the results of HPLC-PDA, FNTI formulations were susciptable to autooxidation. Differentanti-oxidants were tested and results were evaluated following accelerated stability studies (40°C ± 2°C and 75 ±5% relative humidity). Results indicated that using a combination of water soluble and fat soluble antoxidents provided the optimum protection against autooxidation. The reaction was found to follow the zero order reaction kinetics and the KObs and t90% were calculated for each formula.

Efficient catalysts for benzene alkylation with olefins

The experimental data of benzene alkylation with ethylene and propylene in the presence of methyl and ethylchlorosilanes are presented in this article. The catalytic activity series are determined for the methyl and ethylchlorosilanes. These compounds are found to demonstrate high catalytic activity and selectivity in the alkylation reactions and can be used in place of aluminum chloride. The computational study reveals the linear dependence between the charges, acceptor capacities and activities of the catalysts in the alkylation reactions.