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Frontiers in Microbiology 2018The microbial communities in freshwater have raised concerns about the ecosystem and human health. Many ecological environmental problems have been found in urban river...
The microbial communities in freshwater have raised concerns about the ecosystem and human health. Many ecological environmental problems have been found in urban river because of the unreasonable use and long-term wastewater discharge. In this study, we explored the bacterial community composition, abundance of 14 antibiotics and 21 antibiotic resistance genes (ARGs), and water environment features in seven water samples and seven sediment samples from Ba River in Xi'an, China. Results showed and were the dominant phyla in all samples, and sediment samples had a higher bacterial diversity and richness than it in water. Bacterial communities of site 5 and 6 were clustered in discrepant patterns compared to those at remaining sites from other samples. It might be influenced by nutrients, heavy metals and antibiotics. Antibiotics concentrations ranged from 1.26 to 1.61 × 10 ng L in water samples and 1.55 to 4.05 × 10 μg kg in sediment samples. Sulfamerazine (SM1) and erythromycin (ERY) were the chief antibiotics in water samples, while the level of oxytetracycline (OTC) and cefazolin (CFZ) were higher in sediment samples. Canonical correspondence analysis showed that trimethoprim (TMP) was significantly related to in W6, and that SM1 and OTC had positive correlation with in W5. The and had higher pollution abundance ranging from 10 to 10 copies/16S rRNA gene copies in all samples. Significant correlations were observed between ARGs and matching antibiotics, suggesting that antibiotics can pose the selective pressure on ARGs in this river. In summary, these finding might provide some new data to the limited information available on the bacterial community characteristics, abundance of antibiotics and ARGs in urban river of China.
PubMed: 30619235
DOI: 10.3389/fmicb.2018.03191 -
Water Research Feb 2019Sulfonamide antibiotics (SAs) are increasingly detected as aquatic contaminants and exist as different dissociated species depending on the pH of the water. Their...
Sulfonamide antibiotics (SAs) are increasingly detected as aquatic contaminants and exist as different dissociated species depending on the pH of the water. Their removal in sunlit surface waters is governed by photochemical transformation. Here we report a detailed examination of the hydroxyl radical (•OH) and singlet oxygen (O) mediated photooxidation of nine SAs: sulfamethoxazole, sulfisoxazole, sulfamethizole, sulfathiazole, sulfamethazine, sulfamerazine, sulfadiazine, sulfachloropyridazine and sulfadimethoxine. Both •OH and O oxidation kinetics varied depending on the dominant protonated states of the SA in question (HSAs, HSAs and SAs) as a function of pH. Based on competition kinetic experiments and matrix deconvolution calculations, HSAs or SAs (pH ∼5-8) were observed to be more highly reactive towards •OH, while SAs (pH ∼8) react the fastest with O for most of the SAs tested. Using the empirically derived rates of reaction for the speciated forms at different pHs, the environmental half-lives were determined using typical O and •OH concentrations observed in the environment. This approach suggests that photochemical O oxidation contributes more than •OH oxidation and direct photolysis to the overall phototransformation of SAs in sunlit waters. Based on the identification of key photointermediates using tandem mass spectrometry, O oxidation generally occurred at the amino moiety on the molecule, whereas •OH reaction experienced multi-site hydroxylation. Both these reactions preserve the basic parent structure of the compounds and raise concerns that the routes of phototransformation give rise to intermediates with similar antimicrobial potency as the parent SAs. We therefore recommend that these phototransformation pathways are included in risk assessments concerning the presence and fate of SAs in waste and surface waters.
Topics: Anti-Bacterial Agents; Kinetics; Photolysis; Reactive Oxygen Species; Sulfonamides; Water Pollutants, Chemical
PubMed: 30448736
DOI: 10.1016/j.watres.2018.11.009 -
Journal of Analytical Methods in... 2018A multiresidue method for detecting and quantifying sulfonamides (sulfapyridine, sulfamerazine, sulfathiazole, sulfamethazine, sulfadimethoxine, sulfamethoxazole, and...
Multiresidue Method for Quantification of Sulfonamides and Trimethoprim in Tilapia Fillet by Liquid Chromatography Coupled to Quadrupole Time-of-Flight Mass Spectrometry Using QuEChERS for Sample Preparation.
A multiresidue method for detecting and quantifying sulfonamides (sulfapyridine, sulfamerazine, sulfathiazole, sulfamethazine, sulfadimethoxine, sulfamethoxazole, and sulfamethoxypyridazine) and trimethoprim in tilapia fillet () using liquid chromatography coupled to mass spectrometry was developed and validated. The sample preparation was optimized using the QuEChERS approach. The chromatographic separation was performed using a C18 column and 0.1% formic acid in water and acetonitrile as the mobile phase in the isocratic elution mode. Method validation was performed based on the Commission Decision 2002/657/EC and Brazilian guideline. The validation parameters evaluated were linearity ( ≥ 0.99); limits of detection (LOD) and quantification (LOQ), 1 ng·g and 5 ng·g, respectively; intraday and interdays precision (CV lower than 19.4%). The decision limit (CC 102.6-120.0 ng·g and 70 ng·g for sulfonamides and trimethoprim, respectively) and detection capability (CC 111.7-140.1 ng·g and 89.9 ng·g for sulfonamides and trimethoprim, respectively) were determined. Analyses of tilapia fillet samples from fish exposed to sulfamethazine through feed (incurred samples) were conducted in order to evaluate the method. This new method was demonstrated to be fast, sensitive, and suitable for monitoring sulfonamides and trimethoprim in tilapia fillet in health surveillance programs, as well as to be used in pharmacokinetics and residue depletion studies.
PubMed: 29686929
DOI: 10.1155/2018/4506754 -
RSC Advances Apr 2018The residues of sulfonamides in the environment have received widespread attention because of their potential hazards. In this study, the potential of peanut shells for...
The residues of sulfonamides in the environment have received widespread attention because of their potential hazards. In this study, the potential of peanut shells for antibiotic removal from aqueous solutions was investigated for four antibiotics (sulfamerazine, sulfamethazine, sulfathiazole, and sulfamethoxazole). The properties of the peanut shells were characterized using Brunauer-Emmett-Teller method, X-ray photoelectron spectroscopy, scanning electron microscopy and Fourier-transform infrared spectroscopy analyses, and the results of the analyses showed that the significant properties of peanut shells were mainly attributed to the antibiotics' adsorption process. A batch adsorption experiment was conducted to study the effect of dosage, concentration, and water factors (Fe, Mn, and Ca) on antibiotic adsorption. Adsorption kinetics and isotherms were also studied. The kinetic data showed that a pseudo-second order kinetic model fitted the experimental data, the adsorption isotherm experimental data fitted the Henry linear adsorption model well, and methanol was found to be an effective eluent for desorption of the antibiotics. The results indicate that peanut shells are a promising material for the removal of antibiotics from contaminated water, when present at low initial concentrations.
PubMed: 35542553
DOI: 10.1039/c7ra11796e -
Frontiers in Microbiology 2018Halophytes are associated with the intertidal forest ecosystem of Saudi Arabia and seemingly have an immense potential for yielding useful and important natural...
Halophytes are associated with the intertidal forest ecosystem of Saudi Arabia and seemingly have an immense potential for yielding useful and important natural products. In this study we have aimed to isolate and characterize the endophytic and rhizospheric bacterial communities from the halophyte, , In addition these bacterial strains were identified and selected strains were further studied for bioactive secondary metabolites. At least 168 rhizspheric and endophytic bacteria were isolated and of these 22 were active antagonists against the oomycetous fungal plant pathogens, and . Active cultures were mainly identified with molecular techniques (16S r DNA) and this revealed 95.7-100% sequence similarities with relevant type strains. These microorgansims were grouped into four major classes: , β, and γ. Production of fungal cell wall lytic enzymes was detected mostly in members of and . PCR screening for type I polyketide synthases (PKS-I), type II polyketide synthases (PKS-II) and nonribosomal peptide synthetases (NRPS) revealed 13 of the 22 strains (59%) were positive for at least one of these important biosynthetic genes that are known to be involved in the synthesis of important antibiotics. Four bacterial strains of with potential antagonistic activity including two rhizobacteria, EA52 ( sp.), EA58 ( sp.) and endophytic bacteria . (EA65) and sp. (EA67) were selected for secondary metabolite analyses using LC-MS. As a result, the presence of different bioactive compounds in the culture extracts was detected some of which are already reported for their diverse biological activities including antibiotics such as Sulfamethoxypyridazine, Sulfamerazine, and Dimetridazole. In conclusion, this study provides an insight into antagonistic bacterial population especially the from , producing antifungal metabolites of medical significance and characterized taxonomically in future.
PubMed: 29445362
DOI: 10.3389/fmicb.2018.00065 -
Polymers Jan 2018Chitosan powder irradiated by electron beam at different doses, up to 250 kGy, was used to prepare membranes for drug release applications. The irradiation effect on the...
Chitosan powder irradiated by electron beam at different doses, up to 250 kGy, was used to prepare membranes for drug release applications. The irradiation effect on the molecular weight of powder chitosan, the characteristics of the prepared membranes, and their transport of sulfamerazine sodium salt (SULF) were investigated. The effect of the addition of glutaraldehyde (GLA) as a crosslinking agent in the chitosan solution used for the preparation of the membranes was also studied. A decrease in the chitosan molecular weight with the increase in the irradiation dose was observed, while the membranes prepared with the irradiated chitosan at higher dose exhibited lower swelling. However, an opposite behavior was detected when the membranes were prepared with GLA-crosslinked chitosan. A GLA crosslinking agent reduced the crystallinity of the chitosan membranes and the swelling, whereas the water contact angle and SULF transport increased with the increase in the irradiation dose.
PubMed: 30966153
DOI: 10.3390/polym10020117 -
Oxidative Medicine and Cellular... 2017The results of epidemiological and pathophysiological studies suggest that type 2 diabetes mellitus (T2DM) may predispose to Alzheimer's disease (AD). The two conditions...
The results of epidemiological and pathophysiological studies suggest that type 2 diabetes mellitus (T2DM) may predispose to Alzheimer's disease (AD). The two conditions present similar glucose levels, insulin resistance, and biochemical etiologies such as inflammation and oxidative stress. The diabetic state also contributes to increased acetylcholinesterase (AChE) activity, which is one of the factors leading to neurodegeneration in AD. The aim of this study was to assess in vitro the effects of metformin, phenformin, and metformin sulfenamide prodrugs on the activity of human AChE and butyrylcholinesterase (BuChE) and establish the type of inhibition. Metformin inhibited 50% of the AChE activity at micromolar concentrations (2.35 mol/mL, mixed type of inhibition) and seemed to be selective towards AChE since it presented low anti-BuChE activity. The tested metformin prodrugs inhibited cholinesterases (ChE) at nanomolar range and thus were more active than metformin or phenformin. The cyclohexyl sulfenamide prodrug demonstrated the highest activity towards both AChE (IC = 890 nmol/mL, noncompetitive inhibition) and BuChE (IC = 28 nmol/mL, mixed type inhibition), while the octyl sulfenamide prodrug did not present anti-AChE activity, but exhibited mixed inhibition towards BuChE (IC = 184 nmol/mL). Therefore, these two bulkier prodrugs were concluded to be the most selective compounds for BuChE over AChE. In conclusion, it was demonstrated that biguanides present a novel class of inhibitors for AChE and BuChE and encourages further studies of these compounds for developing both selective and nonselective inhibitors of ChEs in the future.
Topics: Acetylcholinesterase; Butyrylcholinesterase; Cholinesterase Inhibitors; Diabetes Mellitus, Type 2; Female; GPI-Linked Proteins; Humans; Male; Metformin; Prodrugs; Sulfamerazine
PubMed: 28770024
DOI: 10.1155/2017/7303096 -
Chemical Research in Toxicology Jun 2017Aromatic amines covalently bound to hemoglobin (Hb) as sulfinamide adducts at the cysteine 93 residue of the Hb β chain have served as biomarkers to assess exposure to...
Quantification of Hemoglobin and White Blood Cell DNA Adducts of the Tobacco Carcinogens 2-Amino-9H-pyrido[2,3-b]indole and 4-Aminobiphenyl Formed in Humans by Nanoflow Liquid Chromatography/Ion Trap Multistage Mass Spectrometry.
Aromatic amines covalently bound to hemoglobin (Hb) as sulfinamide adducts at the cysteine 93 residue of the Hb β chain have served as biomarkers to assess exposure to this class of human carcinogens for the past 30 years. In this study, we report that 2-amino-9H-pyrido[2,3-b]indole (AαC), an abundant carcinogenic heterocyclic aromatic amine formed in tobacco smoke and charred cooked meats, also reacts with Hb to form a sulfinamide adduct. A novel nanoflow liquid chromatography/ion trap multistage mass spectrometry (nanoLC-IT/MS) method was established to assess exposure to AαC and the tobacco-associated bladder carcinogen 4-aminobiphenyl (4-ABP) through their Hb sulfinamide adducts. Following mild acid hydrolysis of Hb in vitro, the liberated AαC and 4-ABP were derivatized with acetic anhydride to form the N-acetylated amines, which were measured by nanoLC-IT/MS. The limits of quantification (LOQ) for AαC- and 4-ABP-Hb sulfinamide adducts were ≤7.1 pg/g Hb. In a pilot study, the mean level of Hb sulfinamide adducts of AαC and 4-ABP were, respectively, 3.4-fold and 4.8-fold higher in smokers (>20 cigarettes/day) than nonsmokers. In contrast, the major DNA adducts of 4-ABP, N-(2'-deoxyguanosin-8-yl)-4-aminobiphenyl, and AαC, N-(2'-deoxyguanosin-8-yl)-2-amino-9H-pyrido[2,3-b]indole, were below the LOQ (3 adducts per 10 bases) in white blood cell (WBC) DNA of smokers and nonsmokers. These findings reaffirm that tobacco smoke is a major source of exposure to AαC. Hb sulfinamide adducts are suitable biomarkers to biomonitor 4-ABP and AαC; however, neither carcinogen binds to DNA in WBC, even in heavy smokers, at levels sufficient for biomonitoring.
Topics: Aminobiphenyl Compounds; Carbolines; Carcinogens; Chromatography, High Pressure Liquid; DNA Adducts; Hemoglobins; Humans; Leukocytes; Mass Spectrometry; Molecular Structure; Nanotechnology; Sulfamerazine; Nicotiana
PubMed: 28493705
DOI: 10.1021/acs.chemrestox.7b00072 -
The Journal of Organic Chemistry Mar 2017The catalytic, enantioselective, cyclization of phenols with electrophilic sulfenophthalimides onto isolated or conjugated alkenes affords 2,3-disubstituted benzopyrans...
The catalytic, enantioselective, cyclization of phenols with electrophilic sulfenophthalimides onto isolated or conjugated alkenes affords 2,3-disubstituted benzopyrans and benzoxepins. The reaction is catalyzed by a BINAM-based phosphoramide Lewis base catalyst which assists in the highly enantioselective formation of a thiiranium ion intermediate. The influence of nucleophile electron density, alkene substitution pattern, tether length and Lewis base functional groups on the rate, enantio- and site-selectivity for the cyclization is investigated. The reaction is not affected by the presence of substituents on the phenol ring. In contrast, substitutions around the alkene strongly affect the reaction outcome. Sequential lengthening of the tether results in decreased reactivity, which necessitated increased temperatures for reaction to occur. Sterically bulky aryl groups on the sulfenyl moiety prevented erosion of enantiomeric composition at these elevated temperatures. Alcohols and carboxylic acids preferentially captured thiiranium ions in competition with phenolic hydroxyl groups. An improved method for the selective C(2) allylation of phenols is also described.
Topics: Alkenes; Catalysis; Cyclization; Magnetic Resonance Spectroscopy; Phenols; Stereoisomerism; Sulfamerazine
PubMed: 28257203
DOI: 10.1021/acs.joc.7b00295 -
Current Protocols in Toxicology Feb 2017Protein sulfenylation is a post-translational modification that is linked to many cell signaling networks and specific protein functions, thus the detection of any...
Protein sulfenylation is a post-translational modification that is linked to many cell signaling networks and specific protein functions, thus the detection of any sulfenylated protein after a toxicological exposure is of importance. Specifically, the detection of protein sulfenylation can provide multiple levels of mechanistic insight towards understanding the impact of a toxicological exposure. For instance, sulfenylation is caused by only a handful of reactive chemical species. Any altered sulfenylation suggests a change in cellular health, and the elucidation of the specific protein target that undergoes sulfenylation can help ascertain downstream targets and associated adverse outcomes. This document describes straightforward approaches to detect protein sulfenylation of total protein as well as individual proteins of interest with a focus on immunoblotting approaches. © 2017 by John Wiley & Sons, Inc.
Topics: Animals; Cattle; Cell Line; Culture Media; Electrophoresis, Polyacrylamide Gel; Oxidative Stress; Protein Processing, Post-Translational; Proteins; Sulfamerazine
PubMed: 28146279
DOI: 10.1002/cptx.16