The Muller F element (4.2 Mb, ~80 protein-coding genes) is an unusual autosome of Drosophila melanogaster; it is mostly heterochromatic with a low recombination rate. To investigate how these properties impact the evolution of repeats and genes, we manually improved the sequence and annotated the genes on the D. erecta, D. mojavensis, and D. grimshawi F elements and euchromatic domains from the Muller D element. We find that F elements have greater transposon density (25–50%) than euchromatic reference regions (3–11%). Among the F elements, D. grimshawi has the lowest transposon density (particularly DINE-1: 2% vs. 11–27%). F element genes have larger coding spans, more coding exons, larger introns, and lower codon bias. Comparison of the Effective Number of Codons with the Codon Adaptation Index shows that, in contrast to the other species, codon bias in D. grimshawi F element genes can be attributed primarily to selection instead of mutational biases, suggesting that density and types of transposons affect the degree of local heterochromatin formation. F element genes have lower estimated DNA melting temperatures than D element genes, potentially facilitating transcription through heterochromatin. Most F element genes (~90%) have remained on that element, but the F element has smaller syntenic blocks than genome averages (3.4–3.6 vs. 8.4–8.8 genes per block), indicating greater rates of inversion despite lower rates of recombination. Overall, the F element has maintained characteristics that are distinct from other autosomes in the Drosophila lineage, illuminating the constraints imposed by a heterochromatic milieu.
We describe the development and validation of a method for the screening and confirmation of a range of chemically diverse synthetic cannabinoid drugs in human whole blood. The method targets the better known arylindole compounds as well as the emerging aminocarbonyl/ carboxamide (NACA) compounds. The approach consists of two separate extraction procedures designed to optimize recovery of each of these two classes, followed by analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The most significant novel compounds added were AB-FUBINACA, ADBICA, 5 F-ADBICA, ADB-PINACA, ADB-FUBINACA, ADB-FUBINACA, 5 F-ADB-PINACA, 5 F-ADB-PINACA, AB-PINACA, AB-CHMINACA, and ADB-CHMINACA. A third procedure is described for the quantitative confirmation of those compounds for which deuterated internal standards permitted quantitative analysis, including JWH-018, JWH-122, JWH-081, JWH-210, AM-2201, XLR-11, and UR-144. The methods were successfully validated according to Scientific Working Group in Forensic Toxicology (SWGTOX) protocol for 34 compounds in common use in the United States in the period of 2014 and 2015, although other substances, unknown at the time may have been introduced to the market over the same time period. The method was determined to be free from carry-over between samples, and no interference was found from other common therapeutic abused or novel psychoactive drugs. The methods were applied to the analysis of 1142 blood samples from forensic investigations, including post-mortem examinations and driving impairment cases. The drugs most frequently detected were AB-CHMINACA (18.6%), ADB-CHMINACA (15%), XLR-11 (5.5%), AB-FUBINACA (4.5%), AB-PINACA (3.9%), and ADB-FUBINACA (2.3%). Copyright © 2016 John Wiley & Sons, Ltd.
We describe the development of a sensitive analytical method for the analysis of 11-hydroxy-delta-9-tetrahydrocannabinol (11-OH-THC) and 11-carboxy-delta-9-tetrahydrocannabinol (THCC) in meconium using a gas chromatography-mass spectrometry (GC/MS) platform. The method was validated according to protocols, which included assessment of accuracy, precision, robustness, stability in meconium and in-process stability, interference and sensitivity and specificity. The method consists of a solid phase extraction with alkaline hydrolysis and derivatization of the analytes with N, O-Bis(trimethylsilyl)trifluoroacteamide, followed by GC/MS analysis using selected ion monitoring. The method uses deuterated internal standards for both analytes. Calibration curves had r(2) values >0.998, and extraction efficiency was determined to be 84.7% for THCC and 78.6% for 11-OH-THC. The detection limit for both analytes was 5 ng/g. This confirmatory method was successfully applied to 183 meconium samples that had screened positive by enzyme-linked immunosorbent assay, and 67.2% were confirmed for THCC, and 2.2% were confirmed positive for 11-OH-THC. The mean (SD) and median (range) THCC (n = 123) concentrations detected were 55.0 ng/g (±59.0) and 33.75 ng/g (5-265 ng/g), while the mean and median (range) for 11-OH-THC (n = 4) concentrations were 8.25 ng/g (±4.71) and 6.5 ng/g (5-15 ng/g).
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