Aqueous two-phase system based on benzethonium chloride and sodium dihexyl sulfosuccinate for extraction and ICP-OES determination of heavy metals.

An aqueous two-phase system (ATPS) based on benzethonium chloride (BztCl) and sodium dihexyl sulfosuccinate (NaDHSS) was proposed for the first time for liquid-liquid microextraction of Cd(II), Co(II), Cu(II), Mn(II), Ni(II), and Pb(II) followed by ICP-OES determination. The mixture of cationic and anionic surfactants, BztCl and NaDHSS, showed liquid-liquid phase separation at the molar ratio of 1:1, and the total surfactant concentration of 0.01-0.2 mol L-1 forming ATPS that was investigated in the extraction process. The extraction efficiency for Cd(II), Co(II), Mn(II), Ni(II), and Pb(II) was nearly 100 %, and for Cu(II) - not lower than 88 % in the presence of 8-hydroxyquinoline as a complexing agent. The surfactant-rich phase containing analytes was subjected to back-extraction with 0.2 M HNO3 before ICP-OES measurements. The preconcentration in the proposed BztCl-NaDHSS-H2O ATPS for 30 s and the high degree of back-extraction, which was achieved in 1 min, significantly reduced the sample preparation time, matrix effects and provided low LODs in the range of 0.04-1.0 µg L-1, the preconcentration factor was 120. The analysis of a certified reference material sample of surface water and the real samples of tap, sea, and waste water verified the method accuracy.

Novel Derivatives of Quinoxaline-2-carboxylic Acid 1,4-Dioxides as Antimycobacterial Agents: Mechanistic Studies and Therapeutic Potential.

The World Health Organization (WHO) reports that tuberculosis (TB) is one of the top 10 leading causes of global mortality. The increasing incidence of multidrug-resistant TB highlights the urgent need for an intensified quest to discover innovative anti-TB medications In this study, we investigated four new derivatives from the quinoxaline-2-carboxylic acid 1,4-dioxide class. New 3-methylquinoxaline 1,4-dioxides with a variation in substituents at positions 2 and 6(7) were synthesized via nucleophilic aromatic substitution with amines and assessed against a Mycobacteria spp. Compound 4 showed high antimycobacterial activity (1.25 µg/mL against M. tuberculosis) and low toxicity in vivo in mice. Selection and whole-genomic sequencing of spontaneous drug-resistant M. smegmatis mutants revealed a high number of single-nucleotide polymorphisms, confirming the predicted mode of action of the quinoxaline-2-carboxylic acid 1,4-dioxide 4 as a DNA-damaging agent. Subsequent reverse genetics methods confirmed that mutations in the genes MSMEG_4646, MSMEG_5122, and MSMEG_1380 mediate resistance to these compounds. Overall, the derivatives of quinoxaline-2-carboxylic acid 1,4-dioxide present a promising scaffold for the development of innovative antimycobacterial drugs.

Bacterial Lux Biosensors in Genotoxicological Studies.

The aim of this study was to assess the applicability of the bacterial lux biosensors for genotoxicological studies. Biosensors are the strains of E. coli MG1655 carrying a recombinant plasmid with the lux operon of the luminescent bacterium P. luminescens fused with the promoters of inducible genes: recA, colD, alkA, soxS, and katG. The genotoxicity of forty-seven chemical compounds was tested on a set of three biosensors pSoxS-lux, pKatG-lux and pColD-lux, which allowed us to estimate the oxidative and DNA-damaging activity of the analyzed drugs. The comparison of the results with the data on the mutagenic activity of these drugs from the Ames test showed a complete coincidence of the results for the 42 substances. First, using lux biosensors, we have described the enhancing effect of the heavy non-radioactive isotope of hydrogen deuterium (D2O) on the genotoxicity of chemical compounds as possible mechanisms of this effect. The study of the modifying effect of 29 antioxidants and radioprotectors on the genotoxic effects of chemical agents showed the applicability of a pair of biosensors pSoxS-lux and pKatG-lux for the primary assessment of the potential antioxidant and radioprotective activity of chemical compounds. Thus, the results obtained showed that lux biosensors can be successfully used to identify potential genotoxicants, radioprotectors, antioxidants, and comutagens among chemical compounds, as well as to study the probable mechanism of genotoxic action of test substance.

Aqueous Two-Phase Systems Based on Cationic and Anionic Surfactants Mixture for Rapid Extraction and Colorimetric Determination of Synthetic Food Dyes.

In this study, aqueous two-phase systems (ATPSs) containing a cationic and anionic surfactants mixture were used for the preconcentration of the synthetic food dyes Allura Red AC, Azorubine, Sunset Yellow, Tartrazine, and Fast Green FCF. A rapid, simple, low cost, affordable, and environmentally friendly methodology based on microextraction in ATPSs, followed by spectrophotometric/colorimetric determination of the dyes, is proposed. The ATPSs are formed in mixtures of benzethonium chloride (BztCl) and sodium N-lauroylsarcosinate (NaLS) or sodium dihexylsulfosuccinate (NaDHSS) under the molar ratio close to equimolar at the total surfactant concentration of 0.01-0.20 M. The density, viscosity, polarity, and water content in the surfactant-rich phases at an equimolar ratio BztCl:NaA were determined. The effects of pH, total surfactant concentration, dye concentration, and time of extraction/centrifugation were investigated, and the optimum conditions for the quantitative extraction of dyes were established. The smartphone-based colorimetric determination was employed directly in the extract without separating the aqueous phase. The analytical performance (calibration linearity, precision, limits of detection and quantification, reproducibility, and preconcentration factor) and comparison of the spectrophotometric and smartphone-based colorimetric determination of dyes were evaluated. The method was applied to the determination of dyes in food samples and food-processing industrial wastewater.

Extraction and ICP-OES determination of heavy metals using tetrabutylammonium bromide aqueous biphasic system and oleophilic collector.

Preconcentration of Cd(II), Co(II), Cu(II), Ni(II), Pb(II), and Zn(II) in aqueous biphasic system tetrabutylammonium bromide (TBAB) - H2O - (NH4)2SO4 followed by ICP-OES determination is reported for the first time. All metal ions extracted quantitatively with 4-(2-pyridylazo)-resorcinol. Nonwoven polypropylene collector was used to capture the extract and to assist phase separation. The concentrate was eluted with 0.3 mol L-1 nitric acid and introduced directly into ICP-OES sampling line. Detection limits for cadmium, cobalt, copper, nickel, lead, and zinc were 0.012, 0.2, 0.17, 0.11, 0.2, and 0.4 µg L-1, respectively; preconcentration factor was 150. The method accuracy was verified by the analysis of certified reference materials samples of waste waters and surface water, as well as the real samples of spring and well water. The use of oleophilic polypropylene collector allowed to handle small volume extract, attain high preconcentration factor and significantly decrease detection limits for ICP-OES determination of heavy metals.

Effect of the C-reactive protein gene on risk and clinical characteristics of schizophrenia in winter-born individuals.

C-reactive protein (CRP) levels are elevated in a subset of schizophrenia patients and correlated with more severe symptoms, which makes CRP a potential theranostic biomarker for the disease. However, genotypes associated with higher CRP concentrations have the protective effect against schizophrenia. To resolve this discrepancy, more research on the role of CRP in schizophrenia is needed. The present study aimed to investigate the effects on schizophrenia of the CRP gene in combination with season of birth (SOB), the known risk factor for the disease. We first examined the impact of seasonality on schizophrenia risk in the Russian population, using samples of 2452 patients and 1203 controls, and then assessed the CRP rs2794521 polymorphism × SOB interaction effect on the disease risk, age-of-onset and symptoms severity in 826 patients and 476 controls. An excess of winter births in patients was not significant. At the same time, we found that winter-born patients carrying the CRP GG genotype, which is associated with low transcriptional activity, had an earlier age at onset than the other patients. The findings are in line with the protective role of high active CRP genetic variants in the development of schizophrenia and provide support for the hypothesis that this effect of CRP takes place early in life.

Multielement Determination of Trace Heavy Metals in Water by Microwave-Induced Plasma Atomic Emission Spectrometry after Extraction in Unconventional Single-Salt Aqueous Biphasic System.

For the first time liquid-liquid extraction was used for the preconcentration of heavy metals prior to their determination in water by microwave-induced plasma atomic emission spectrometry (MP-AES). Extraction of Pb(II), Cd(II), Co(II), Ni(II), Zn(II), and Cu(II) was performed in unconventional aqueous biphasic system (ABS) formed by addition of hydrophobic solid salt, namely, tetrahexylammonium bromide, to aqueous sample, with neither organic solvents nor salting-out agents being used. The metal ions were quantitatively recovered with 4-(2-pyridylazo)-resorcinol (PAR). The extract was diluted with ethanol/HCl and introduced directly into an MP-AES instrument. The factors influencing extraction (pH, reagent concentration, phase contact time, etc.) and MP-AES detection parameters were studied and optimized. For the developed method, limits of detection of 1.3, 4.9, 0.06, 1.2, 4.2, and 3.2 µg L-1 were obtained for cadmium, cobalt, copper, nickel, lead, and zinc, respectively, providing from 60- to 500-fold improvement as compared with the analysis without preconcentration. The method was applied for the analysis of two certified reference materials (CRM) of wastewater and surface water as well as the samples of well and seawater. Coupling MP-AES with ABS extraction significantly extends the capabilities of the method, especially for the analysis of high salinity waters.

Genetic dissection of host immune response in pneumonia development and progression.

The role of host genetic variation in pneumonia development and outcome is poorly understood. We studied common polymorphisms in the genes of proinflammatory cytokines (IL6 rs1800795, IL8 rs4073, IL1B rs16944), anti-inflammatory cytokines (IL10 rs1800896, IL4 rs2243250, IL13 rs20541) and toll-like receptors (TLR2 rs5743708 and rs4696480, TLR4 rs4986791, TLR9 rs352139, rs5743836 and rs187084) in patients with community-acquired pneumonia (CAP) (390 cases, 203 controls) and nosocomial pneumonia (355 cases, 216 controls). Experimental data were included in a series of 11 meta-analyses and eight subset analyses related to pneumonia susceptibility and outcome. TLR2 rs5743708 minor genotype appeared to be associated with CAP/Legionnaires' disease/pneumococcal disease. In CAP patients, the IL6 rs1800795-C allele was associated with severe sepsis/septic shock/severe systemic inflammatory response, while the IL10 rs1800896-A allele protected against the development of these critical conditions. To contribute to deciphering of the above results, we performed an in silico analysis and a qualitative synthesis of literature data addressing basal and stimulated genotype-specific expression level. This data together with database information on transcription factors' affinity changes caused by SNPs in putative promoter regions, the results of linkage disequilibrium analysis along with SNPs functional annotations supported assumptions about the complexity underlying the revealed associations.

Immunological parameters and gene polymorphisms (C-590T IL4, C-597A IL10) in severe bronchial asthma in children from the Krasnoyarsk region, West Siberia.

BACKGROUND: Bronchial asthma is a common disease caused by interplay between multiple determinants, including genetic and immune variations. OBJECTIVE: To investigate the main indices of humoral and cellular branches of immunity, features of cytokine regulation and cytokine genes in children with atopic bronchial asthma (BA) with different levels of disease control. DESIGN: Fifty children with controlled BA (CBA) and 50 with uncontrolled BA (UBA) were analyzed. Mean age in the sample was 13.36 ± 2.24 years. A control group of healthy children (n = 50) was also studied. All individuals were Russians (Eastern Slavs) from the Krasnoyarsk Territory, West Siberia. Diagnoses, severity and level of disease control were defined according to the Global Initiative for Asthma (GINA) recommendations. The lymphocytes were counted in blood using fluorescent microscopy. Humoral branch indices and cytokine levels (IL-2, IL-4, IL-10 and TNF-α) in blood serum were measured by ELISA. Genotyping of single-nucleotide polymorphism (SNP) in -590 position of the IL4 and -597 position of the IL10 gene was performed by restriction fragment length analysis. RESULTS: No statistically significant differences in total IgE and cytokines blood levels were found in CBA and UBA. However, significant differences between the groups were found for CD(3+), CD(4+) and CD(8+) cell counts. The T-590 allele of the IL4 gene, which is responsible for an increased serum level of IL-4, showed a tendency to an association with UBA. A decreased level of IL-10 enhances control over BA, which proves its association with the allelic variant A-597 IL10. CONCLUSION: Our data show that children with UBA have higher counts of CD(3+) cells and an increase of sub-population of CD(4+)-cells as well as higher levels of IgE, IL-4 and TNF-α in blood serum as compared to CBA. Polymorphisms of the IL4 and IL10 genes are associated with allergic inflammation in UBA.

The peculiarities of food allergies in accordance with the level of injury of respiratory tract in children of Eastern Siberia.

AIM: To determine the course of food allergy in accordance with the level of respiratory tract injury in children of Eastern Siberia. DESIGN OF THE RESEARCH: We have examined 70 children aged 2-16 , who have food sensibilization. We divided them into 2 groups: group I (n = 32) with diseases of the upper and middle respiratory tract; and group II (n = 38) with diseases of the lower respiratory tract. METHODS: Allergological medical history, clinical laboratory examination and immunological examination, including the determination of IgA, IgM, IgG and IgE in blood serum. In cases where causal allergens were found, elimination diets were recommended. RESULTS: Onset of upper respiratory tract injury in group I was more often registered in children aged 0-1; in group II, it was in the 3-7 age group. Isolated food sensibilization was more often marked in group I as compared to group II. Atopic mechanisms of respiratory tract injuries were more often registered in group II children. In the course of the elimination diet, we marked positive dynamics in 100% of group I and in 75% of group II. CONCLUSION: The most frequent allergens that cause respiratory forms of food allergy are hen eggs, cow milk, nutritive cereals, vegetables and fruit. Indices of a humoral link of immunity in the examined patients were more often registered as normal or their level is increased. Timely etiotropic therapy in the majority of cases allows for a stabilization of allergic inflammation.

Task-specific ionic liquid trioctylmethylammonium salicylate as extraction solvent for transition metal ions.

A quaternary ammonium-based room temperature ionic liquid trioctylmethylammonium salicylate (TOMAS) has been studied as an extractant of transition metal ions (Fe(3+), Cu(2+), Ni(2+), Mn(2+)) in aqueous solutions. The effect of pH value on the recovery of metal ions has been investigated. The mechanism of extraction into the ionic liquid has been proposed. The possibility of stripping voltammetric determination of transition metals in aqueous solutions using TOMAS-modified electrodes has been demonstrated.

18-Crown-6 and dibenzo-18-crown-6 assisted extraction of cesium from water into room temperature ionic liquids and its correlation with stability constants for cesium complexes.

The pH-profiles of the extraction of Cs(+) into four conventional (1-butyl-3-methylimidazolium hexafluorophosphate and bis[trifluoromethyl)sulphonyl]imides of 1-butyl-3-methylimidazolium, 1-hexyl-3-methylimidazolium, and 1-(2-ethylhexyl)-3- methylimidazolium) and two novel (trioctylmethylammonium salicylate and tetrahexylammonium dihexylsulfosuccinate) room temperature ionic liquids have been determined both in the absence and in the presence of crown ether (18-crown-6 or dibenzo-18-crown-6). The pH-profiles of distribution ratio of crown ethers have been established in the same conditions. The relationship of cesium extraction efficiency both with the stability of its complexes with crown ethers and crown ethers' distribution ratio has been clarified.

Dissolution of cellulose in ionic liquids as a way to obtain test materials for metal-ion detection.

Cellulose films containing entrapped analytical reagents suitable for metal-ion detection are produced by joint dissolution of cellulose and the reagents in ionic liquids then precipitation with water. The conditions of preparation of these test materials have been optimized and their properties have been studied. The film obtained by use of the ionic liquid 1-butyl-3-methylimidazolium chloride and 1-(2-pyridylazo)-2-naphthol has been used for colorimetric determination of divalent zinc, manganese, and nickel with detection limits at the 10(-6) mol L-1 level.

Solvent extraction and extraction-voltammetric determination of phenols using room temperature ionic liquid.

The phenolic compounds phenol, 4-nitrophenol, 2,4-dinitrophenol, 2,6-dinitrophenol, 1-naphthol, 2-naphthol, and 4-chlorophenol are extracted nearly quantitatively from aqueous solution into the room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMImPF6) in molecular form at pH < p Ka. Picric acid is extracted efficiently in anionic form. Recovery of pyrocatechol and resorcinol is much lower. The effect of pH, phenol concentration, and volume ratio of aqueous and organic phases were studied. Ionic liquid BMImPF6 is shown to be suitable for extraction-voltammetric determination of phenols without back-extraction or addition of support electrolyte. The electrochemical window of BMImPF6 at various electrodes was determined, and voltammetric oxidation of phenols and reduction of nitrophenols in BMImPF6 was studied.

Solvent extraction of amino acids into a room temperature ionic liquid with dicyclohexano-18-crown-6.

Amino acids Trp, Gly, Ala, Leu are extracted efficiently from aqueous solution at pH 1.5-4.0 (Lys and Arg at pH 1.5-5.5) into the room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BmimPF(6)) with dicyclohexano-18-crown-6 (CE). The most hydrophilic amino acids such as Gly are extracted as efficiently as the less hydrophilic (92-96%). The influence of pH, amino acid and crown ether concentration, volume ratio of aqueous and organic phases, and presence of some cations on amino acid recovery were studied. The ratio of amino acid to crown ether in the extracted species is 1:1 for cationic Trp, Leu, Ala, and Gly and to 1:2 for dicationic Arg and Lys. This ionic liquid extraction system was used successfully for the recovery of amino acids from pharmaceutical samples and fermentation broth, and was followed by fluorimetric determination.