Simultaneous determination of natural and synthetic steroid estrogens and their conjugates in aqueous matrices by liquid chromatography / mass spectrometry

An analytical method for the simultaneous determination of nine free and conjugated steroid estrogens was developed with application to environmental aqueous matrices. Solid phase extraction (SPE) was employed for isolation and concentration, with detection by liquid chromatography/mass spectrometry (LC/MS) using electrospray ionisation (ESI) in the negative mode. Method recoveries for various aqueous matrices (wastewater, lake and drinking water) were determined, recoveries proving to be sample dependent. When spiked at 50 ng/l concentrations in sewage influent, recoveries ranged from 62-89 % with relative standard deviations (RSD) < 8.1 %. In comparison, drinking water spiked at the same concentrations had recoveries between 82-100 % with an RSD < 5%. Ion suppression is a known phenomenon when using ESI; hence its impact on method recovery was elucidated for raw sewage. Both ion suppression from matrix interferences and the extraction procedure has bearing on the overall method recovery. Analysis of municipal raw sewage identified several of the analytes of interest at ng/l concentrations, estriol (E3) being the most abundant. Only one conjugate, estrone 3-sulphate (E1-3S) was observe

The khmer software package: enabling efficient nucleotide sequence analysis [version 1; referees: 2 approved, 1 approved with reservations]

The khmer package is a freely available software library for working efficiently with fixed length DNA words, or k-mers. khmer provides implementations of a probabilistic k-mer counting data structure, a compressible De Bruijn graph representation, De Bruijn graph partitioning, and digital normalization. khmer is implemented in C++ and Python, and is freely available under the BSD license at https://github.com/dib-lab/khmer/

What Is New for an Old Molecule? Systematic Review and Recommendations on the Use of Resveratrol

Stilbenes are naturally occurring phytoalexins that generally exist as their more stable E isomers. The most well known natural stilbene is resveratrol (Res), firstly isolated in 1939 from roots of Veratrum grandiflorum (white hellebore) (1) and since then found in various edible plants, notably in Vitis vinifera L. (Vitaceae) (2). The therapeutic potential of Res covers a wide range of diseases, and multiple beneficial effects on human health such as antioxidant, anti-inflammatory and anti-cancer activities have been suggested based on several in vitro and animal studies (3). In particular, Res has been reported to be an inhibitor of carcinogenesis at multiple stages via its ability to inhibit cyclooxygenase, and is an anticancer agent with a role in antiangiogenesis (4). Moreover, both in vitro and in vivo studies showed that Res induces cell cycle arrest and apoptosis in tumor cells (4). However, clinical studies in humans evidenced that Res is rapidly absorbed after oral intake, and that the low level observed in the blood stream is caused by a fast conversion into metabolites that are readily excreted from the body (5). Thus, considerable efforts have gone in the design and synthesis of Res analogues with enhanced metabolic stability. Considering that reduced Res (dihydro- resveratrol, D-Res) conjugates may account for as much as 50% of an oral Res dose (5), and that D-Res has a strong proliferative effect on hormone-sensitive cancer cell lines such as breast cancer cell line MCF7 (6), we recently devoted our synthetic efforts to the preparation of trans-restricted analogues of Res in which the E carbon-carbon double bond is embedded into an imidazole nucleus. To keep the trans geometry, the two aryl rings were linked to the heteroaromatic core in a 1,3 fashion. Based on this design, we successfully prepared a variety of 1,4-, 2,4- and 2,5-diaryl substituted imidazoles including Res analogues 1, 2 and 3, respectively, by procedures that involve transition metal-catalyzed Suzuki-Miyaura cross-coupling reactions and highly selective N-H or C-H direct arylation reactions as key synthetic steps. The anticancer activity of compounds 1–3 was evaluated against the 60 human cancer cell lines panel of the National Cancer Institute (NCI, USA). The obtained results, that will be showed and discussed along with the protocols developed for the preparation of imidazoles 1–3, confirmed that a structural optimization of Res may provide analogues with improved potency in inhibiting the growth of human cancer cell lines in vitro when compared to their natural lead. (1) Takaoka,M.J.Chem.Soc.Jpn.1939,60,1090-1100. (2) Langcake, P.; Pryce, R. J. Physiological. Plant Patology 1976, 9, 77-86. (3) Vang, O.; et al. PLoS ONE 2011, 6, e19881. doi:10.1371/journal.pone.0019881 (4) Kraft, T. E.; et al. Critical Reviews in Food Science and Nutrition 2009, 49, 782-799. (5) Walle, T. Ann. N.Y. Acad. Sci. 2011, 1215, 9-15. doi: 10.1111/j.1749-6632.2010.05842.x (6) Gakh,A.A.;etal.Bioorg.Med.Chem.Lett.2010,20,6149-6151