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In many arid and semi-arid systems, biological communities in river ecosystems are submitted to flow interruption and desiccation, as well as to the impact of urban wastewaters. In this work, we studied (using a LC-LTQ-Orbitrap) the metabolomic response of biofilm communities exposed to both hydrological and chemical stressors. Fluvial biofilms were exposed to a mixture of 9 pharmaceuticals at a total concentration of 5000ng/L (mimicking concentrations and compounds found in polluted aquatic environments) and/or to seven days of desiccation, under laboratory conditions. The biosynthesis of fatty acids was the main metabolic pathway disrupted in biofilms. Endogenous biofilm's metabolites (metabolome) altered due to these stressors were identified. The metabolites that significantly changed only due to one of the stressors could be proposed as potential specific biomarkers. A biomarker of pharmaceutical exposure was the lysophosphatidic acid, which decreased a 160%, while for desiccation stearidonic acid (increased 160%), 16-Oxohexadecanoic acid (increased 340%) and palmitoleic acid (decreased 290%) were the biomarkers proposed. Besides, other metabolites showed different responses depending on the treatment, such as palmitic acid, linolenic acid, behenic acid, lignoceric acid and azelaic acid. The Carbon:Phosphorus (C:P) molar ratio increased due to all stress factors, whereas the algal community composition changed mainly due to desiccation. A possible relationship between those changes observed in structural parameters and the metabolome of biofilms was explored. Overall, our findings support the use of metabolomics to unravel at molecular level the effects from chemical and physical stressors on complex microbial communities, such as biofilms, and pinpoint biomarkers of exposure.

This study was aimed to determine the abundance of four antibiotic resistance genes (blaTEM, ermB, qnrS and sulI), as well as bacterial community composition associated with the intestinal mucus of wild freshwater fish species collected from the Foix and La Llosa del Cavall reservoirs, which represent ecosystems with high and low anthropogenic disturbance, respectively. Water and sediments from these reservoirs were also collected and analyzed to determine the pollution level by antibiotics. The blaTEM gene was only detected in brown trout and Ebro barbel, which were collected from La Llosa del Cavall reservoir. In contrast, the sulI and qnrS genes were only detected in common carp, which were collected from the Foix reservoir. Although the ermB gene was also detected in common carp, the values were below the limit of quantification. Likewise, water and sediment samples from the Foix reservoir had higher concentrations and more classes of antibiotics than those from La Llosa del Cavall. Pyrosequencing analysis of 16S rRNA genes revealed significant differences in bacterial communities associated with the intestinal mucus of fish species. Therefore, these findings suggest that anthropogenic activities are not only increasing the pollution of aquatic environments, but also contributing to the emergence and spread of antibiotic resistance in organisms that inhabit such environments.

Fish are good indicators of aquatic environment pollution because of their capability to uptake pollutants contained in water. Therefore, accumulation of pharmaceutical compounds in freshwater and marine fish and other aquatic organisms has been studied extensively in the last decade. In this context, the present study investigates the occurrence of pharmaceutical compounds in wild fish from 25 polluted river sites in the USA, downstream from wastewater treatment plants (WWTPs). Sample sites constitute a subset of urban rivers investigated in the U.S. EPA's 2008–2009 National Rivers and Streams Assessment. Thirteen pharmaceuticals (out of the twenty compounds analyzed) were quantified in fish fillets at concentrations commonly below 10ngg−1, in accordance with the findings from previous studies in the USA and Europe. The psychoactive drugs venlafaxine, carbamazepine and its metabolite 2-hydroxy carbamazepine were the most prevalent compounds (58%, 27% and 42%, respectively). This group of drugs is highly prescribed and rather resistant to degradation during conventional treatment in WWTPs as well as in natural aquatic environments. Salbutamol, a drug used to treat asthma, and the diuretic hydrochlorothiazide were also frequently detected (in >20% of the samples). Occurrence of six pharmaceutical families due to chronic exposure at environmental concentrations in water was detected in eight fish species.

The excellent O-regioselectivity of the glycosidation of the ambident 2-O-substituted 5-fluorouracil (5-FU) via the silver salt method is computationally investigated at the MP2/6-311++G(2d,p):DZP//B3LYP/6-31+G(d):DZP level of theory. The reactions studied are those between 1-bromo-1-deoxy-2,3,4,6-tetra-O-acetyl-α-d-glucopyranose and the silver salts of 5-FU, 2-O-butyl-5-FU, and 2-O-benzyl-5-FU. Two pathways are considered as follows: (A) one where the silver and bromide ion do not interact, and (B) another where the silver and bromide ion interact in the transition states. Because the O-reaction barriers are much lower (by 13.3-22.2 kcal/mol) than N-reaction barriers in both pathways, the O-regioselectivity of the silver salt method can be satisfactorily explained by either path A or path B. Furthermore, path B, where Ag and Br interact consistently, has lower activation barriers than the corresponding path A (by 6.8-17.4 kcal/mol) in both N- and O-reactions. This computational result can be attributed to the following reasons: (1) the speeding-up effect in Koenigs-Knorr reactions due to the addition of silver carbonate into the reaction mixture; (2) the halogens being pulled away by silver ions from halides, as proposed by Kornblum and co-workers; and (3) the oxocarbenium ion involvement in the glycosidation reactions. The large energy difference between N- and O-transition states originates from the association between Ag and N-(O-) of the ambident unit (-N3-C4=O4) that shows significant covalent character so that the O-reaction transition states of the silver salt method benefit from favorable ionic interaction (C+···O-) and favorable covalent interaction (Ag···N). These two favorable interactions are in agreement with the hard and soft acids and bases principle; the former is a hard-hard interaction and the latter is a soft-soft interaction. © 2018 American Chemical Society.

BACKGROUND/AIMS: Variability in the grade of atherosclerosis among patients with chronic kidney disease (CKD) could affect the ultrasound measurements of intima media thickness (IMT). We sought to investigate IMTs of carotid (cIMT) and femoral (fIMT) arteries in CKD patients and assess the degree of their correlation with histopathological atherosclerosis., METHODS: Eighty-nine out of 99 enrolled subjects completed this study. The subjects were divided into 3 groups: 34 patients with CKD (Case group), 31 with coronary artery disease undergoing coronary artery bypass graft (CABG, positive control group), and 24 healthy kidney donors (negative control group). For histopathological assessment of atherosclerosis, arterial tissue samples were obtained from the patients in each study group. The cIMT and fIMTs were measured by ultrasonography., RESULTS: Histopathological atherosclerosis was present in 82.3, 100, and 20.8% of CKD, CABG, and donor groups respectively (p < 0.001). CKD patients had higher values of cIMT and fIMT than the donor group (p = 0.01 and 0.004, respectively). cIMT was positively correlated with the grade of atherosclerosis in the CKD group only (p < 0.001), while fIMT was correlated with the grade of atherosclerosis in both CKD and donor groups (p < 0.001 and p = 0.009 respectively). In CKD patients, cIMT >0.65 mm and femoral values >0.57 mm predicted the presence of histopathological atherosclerosis with sensitivities of 96 and 92% respectively., CONCLUSION: Higher values of cIMT and fIMT in CKD patients are associated with higher rates and degrees of histopathological atherosclerosis. Additionally, when compared to fIMT, cIMT has a higher sensitivity for detecting atherosclerosis in CKD patients. Copyright © 2018 S. Karger AG, Basel.

Fentanyl and its derivatives have become pervasive contaminants in the U.S. heroin supply. Previously, we reported a proof-of-concept vaccine designed to combat against heroin contaminated with fentanyl. Herein, we optimized the admixture vaccine and found that it surpassed the individual vaccines in every antinociceptive test, including a 10% fentanyl to heroin formulation. It is anticipated that other co-occurring drug abuse disorders may also be examined with admixture vaccines. © 2018 American Chemical Society.

Background: In previous reports, the antibacterial properties of certain tetrazole derivatives have been described. We have previously reported the antibac...

An undergraduate experiment for the organic laboratory is described that utilizes microwave heating to prepare 5-substituted 1H-tetrazole derivatives through a (3 + 2) cycloaddition between aryl nitriles and sodium azide. The reaction mixture is analyzed by thin layer chromatography. The products are purified through an acid–base extraction and recrystallization. Characterization is accomplished using melting point, infrared, 1H NMR, and 13C NMR spectroscopy. Students are tasked with determining and confirming the structure of their product based on their assigned nitrile and characterization data.

Boron compounds have been used extensively in organic synthesis for more than sixty years. Some of the best known reactions in synthesis, such as the Suzuki-Miyaura cross-coupling and the hydroboration reaction, involve boron compounds. Several natural products containing boron have been isolated in the last fifty years, including ionophoric macrodiolide antibiotics boromycin, borophycin, aplasmomycins A, B, and C, and tartrolons B, C, and E, as well as autoinducer-2. The study of compounds containing boronic acids for application in pharmaceuticals and materials science has grown tremendously over the last few decades. These include bortezomib, ixazomib, and tavaborole. Several more boron-based drugs are currently in clinical trials. Boron neutron capture therapy has the potential to provide a treatment for various cancers. In addition, materials bearing boronic acids are been studied as potential sensors for biological molecules, such as saccharides and glycoproteins that possess cis-1,2- or cis-1,3-diols.

This study confronts the questionable reliability and accuracy of field test kits distributed globally to determine arsenic in drinking water. Because kits are the primary method of arsenic analysis in the areas most affected, an alternate, nontoxic formulation is needed to provide accurate results. Hypothesizing that introducing silver nitrate as the reagent in test kits could successfully substitute for restricted mercuric bromide, the study found that the reformulated kits provided reliable, precise, and accurate results over a broader range of contamination. Digital image analysis was used to examine the blue color value produced when arsine reacts with silver nitrate impregnated test strips. An optimal concentration of AgNO3 exhibiting the greatest linearity was determined by graphical comparison and the color intensity of the strips observed to be inversely proportional to the concentration of As (III). Adapted field test kits were then constructed to examine water samples ranging in arsenic contamination from 0 to 50 μg L−1. A series of reactions was completed to demonstrate reproducibility and test for the accuracy of the procedure. Statistical examination of colorimetrically quantified results confirmed the hypothesis that silver nitrate can reliably and precisely expand the kit’s range of detection while maintaining its low cost, quick assessment, and uncomplicated technique. This new method, using 0.4% m/v AgNO3 as a reagent for the Gutzeit reaction, was able to distinguish between concentrations of 0, 5, 10, 15, and 50 μg L−1 at the 95% confidence level. © 2018, Springer International Publishing AG, part of Springer Nature.

Various reasons are attributed to poor student performance in physical science courses such as lack of motivation, lack of ability, and/or the overall difficulty of these courses. One overlooked reason is a lack of self-awareness as to preparation level. Through a study over a two-year period, students at all levels (freshman through M.S.) of a chemistry program were surveyed and asked to self-report predictions of their score on examinations. At all levels, strong evidence of the Kruger–Dunning effect was seen where higher performing students tended to underpredict their examination scores while the lowest performing students tended to grossly overpredict their scores.