Oxidation of retinoic acids in hepatic microsomes of wild bullfrogs Lithobates catesbeianus environmentally-exposed to a gradient of agricultural contamination

Environmentally friendly stability-indicating HPLC method for the determination of isotretinoin in commercial products and solubility samples

In this study, an environmentally friendly "high-performance liquid chromatography (HPLC)" assay to quantify isotretinoin (ITN) in commercial products and solubility samples is designed and verified. A Nucleodur reverse-phase C18 column was used as the stationary phase to identify ITN. The ecologically friendly mobile phase was composed of ethyl acetate and ethanol (50:50 v/v), and it was delivered at a flow rate of 1.0 mL/min. ITN was measured at 354 nm in wavelength. The current HPLC method had a determination coefficient of 0.9994 and was linear in the 0.2-80 μg/g range. The current protocol for ITN measurement was also rapid (retention time = 2.78 min), accurate (%recoveries = 98.60-101.52), precise (% uncertainties = 0.71-0.98), and sensitive. According to the AGREE methodology, the current procedure received an outstanding greenness profile with an AGREE score of 0.76. By determining ITN in commercial products and solubility samples, the applicability of the current approach was proven. ITN was discovered to be present in 98.43% and 100.84%, respectively, of commercial capsule brands A and B. The ITN's solubility in numerous eco-friendly solvents was successfully measured. Under different stress conditions, the current approach was able to distinguish between its degradation products, demonstrating its stability-indicating characteristics. These findings indicated that ITN in procured capsules and solubility samples might be regularly tested by the suggested approach.

Charting a path towards non-destructive biomarkers in threatened wildlife: A systematic quantitative literature review

Threatened species are susceptible to irreversible population decline caused by adverse sub-lethal effects of chemical contaminant exposure. It is therefore vital to develop the necessary tools to predict and detect these effects as early as possible. Biomarkers of contaminant exposure and effect are widely applied to this end, and a significant amount of research has focused on development and validation of sensitive and diagnostic biomarkers. However, progress in the use biomarkers that can be measured using non-destructive techniques has been relatively slow and there are still many difficulties to overcome in the development of sound methods. This paper systematically quantifies and reviews studies that have aimed to develop or validate non-destructive biomarkers in wildlife, and provides an analysis of the successes of these methods based on the invasiveness of the methods, the potential for universal application, cost, and the potential for new biomarker discovery. These data are then used to infer what methods and approaches appear the most effective for successful development of non-destructive biomarkers of contaminant exposure in wildlife. This review highlights that research on non-destructive biomarkers in wildlife is severely lacking, and suggests further exploration of in vitro methods in future studies.

Plasma retinoids concentration in Leptodactylus chaquensis (Amphibia: Leptodactylidae) from rice agroecosystems, Santa Fe province, Argentina

Retinoids are known to regulate important processes such as differentiation, development, and embryogenesis of vertebrates: Alteration in endogenous retinoids concentration is linked with teratogenic effects. Retinol (ROH), retinoid acid (RA), and isoform 13-Cis-retinoic acid (13-Cis-RA), in plasma of a native adults frog, Leptodactylus chaquensis from a rice field (RF) and a forest (reference site; RS) were measured. ROH did not vary between treatment sites. RA and 13-Cis-RA activities were higher (93.7±8.6 μg mL(-1) and 131.7±11.4 μg mL(-1), respectively) in individuals collected from RF than in those from RS (65.5±8.6 μg mL(-1) and 92.2±10.2 μg mL(-1), respectively). The ratios retinoic acid-retinol (RA/ROH) and 13-Cis-RA/ROH revealed significantly higher values in RF than in RS. RA and 13-Cis-RA concentrations in plasma on wild amphibian's species such as L. chaquensis would be suitable biomarkers of pesticide exposure in field monitoring. Finally, the mechanism of alteration in retinoid metabolites alteration should be further explored both in larvae and adult, considering that the potential exposition and uptake contaminants vary between the double lives of these vertebrates.