Unveiling the nonlinear optical response of Trictenotoma childreni longhorn beetle

The wings of some insect species are known to fluoresce under illumination by ultraviolet light. Their fluorescence properties are however, not comprehensively documented. In this article, the optical properties of one specific insect, the Trictenotoma childreni yellow longhorn beetle, were investigated using both linear and nonlinear optical (NLO) methods, including one- and two-photon fluorescence and second harmonic generation (SHG). These three distinct optical signals discovered in this beetle are attributed to the presence of fluorophores embedded within the scales covering their elytra. Experimental evidence collected in this study indicates that the fluorophores are non-centrosymmetric, a fundamental requirement for SHG. This study is the first reported optical behavior of this type in insects. We described how NLO techniques can complement other more convenient approaches to achieve a more comprehensive understanding of insect scales and integument properties

Human Colon Microbiota Transform Polycyclic Aromatic Hydrocarbons to Estrogenic Metabolites

Ingestion is an important exposure route for polycyclic aromatic hydrocarbons (PAHs) to enter the human body. Although the formation of hazardous PAH metabolites by human biotransformation enzymes is well documented, nothing is known about the PAH transformation potency of human intestinal microbiota. Using a gastrointestinal simulator, we show that human intestinal microbiota can also bioactivate PAHs, more in particular to estrogenic metabolites. PAH compounds are not estrogenic, and indeed, stomach and small intestine digestions of 62.5 nmol naphthalene, phenanthrene, pyrene, and benzo(a)pyrene showed no estrogenic effects in the human estrogen receptor bioassay. In contrast, colon digests of these PAH compounds displayed estrogenicity, equivalent to 0.31, 2.14, 2.70, and 1.48 nmol 17α-ethynylestradiol (EE2), respectively. Inactivating the colon microbiota eliminated these estrogenic effects. Liquid chromatography–mass spectrometry analysis confirmed the microbial PAH transformation by the detection of PAH metabolites 1-hydroxypyrene and 7-hydroxybenzo(a)pyrene in colon digests of pyrene and benzo(a)pyrene. Furthermore, we show that colon digests of a PAH-contaminated soil (simulated ingestion dose of 5 g/day) displayed estrogenic activity equivalent to 0.58 nmol EE2, whereas stomach or small intestine digests did not. Although the matrix in which PAHs are ingested may result in lower exposure concentrations in the gut, our results imply that the PAH bioactivation potency of colon microbiota is not eliminated by the presence of soil. Moreover, because PAH toxicity is also linked to estrogenicity of the compounds, the PAH bioactivation potency of colon microbiota suggests that current risk assessment may underestimate the risk from ingested PAHs

A rapid and sensitive liquid chromatography-tandem mass spectrometry method for the determination of amphetamine and related designer drugs in urine

A method for the direct analysis of six amphetamine compounds in urine was developed using liquid chromatography tandem mass spectrometry (LC-MS/MS). We added 90 μl of a solution of internal standards (1 pg/mL of d5-AMP, d5-MET, d5-MDA, d5-MDMA, d5-MDEA and d5-MBDB) to 10 μl of urine followed, by vortex-mixing and centrifugation. The sample solutions were analyzed by LC-MS/MS in the MRM mode after separation on a reversed-phase C18 column using gradient elution. Separation and detection of all compounds was accomplished within eight minutes. Linearity was established for all compounds, from 78 to 100000 ng/mL. Correlation coefficients for all analytes exceeded 0.998. The lower limit of quantification was 10 ng/mLfor all compounds, except for AMP and MDA (78 ng/mL). Withinday imprecision (CV%) and between-day CVs (78, 625 and 10000 ng/mL) rangedfrom 2.62 to 16.26% andfrom 0.86 to 11.98%, respectively. Accuracy (bias%) lay between 0.16 and 7.17 %. The peak areas of the amphetamines added to urine fell in the range 85-115% compared to standard solutions in methanol/water; except for AMP and MDA. Carryover was negligible and stability after storage at room temperature for up to 24h was acceptable. In conclusion, the presented method allows the accurate, precise and rapid determination of six amphetamine compounds in urine over a wide analytical range

Complement insubordination in Germanic

status: publishe