Molecular and structural changes induced by essential oil treatments in Vicia faba roots detected by FTIR and FTNIR spectroscopy.

Essential oils have recognized antimicrobial and antifungal properties which allow their utilization in agriculture like an alternative to pesticides, but their utilization requires the knowledge of all the potential structural changes and damages produced by the interaction with the vegetal organisms. In this paper, we investigated the effects of two essential oils, the tea tree oil (TTO) and the mixture of clove and rosemary oils (C + R), on the molecular structure of Vicia faba roots by Fourier transform infrared (FTIR) and Fourier near infrared transform (FTNIR) spectroscopy. FTIR spectroscopy showed structural modifications of the absorption bands related to DNA (1100 and 1050 cm-1, carbohydrate backbones, and nucleotide bands within 900 and 850 cm-1), proteins (1700 and 1600 cm-1 amide I band, 1580 and 1520 cm-1 amide II band), and lipids (methylene group of aliphatic chains between 2950 and 2800 cm-1). The changes in the secondary structures of proteins consisted of a denaturation depending on increased presence of random coil structures. In addition, in the samples treated with TTO oils, we observed the presence of protein oxidation, an effect negligible instead for the C + R-treated samples. The modified shapes of the infrared methyl bands of aliphatic chains suggested an increased lipid disorder which could also determine lipid peroxidation. The changes observed for the DNA structures at the highest concentration of the above essential oils can be related to the genotoxic effect of eugenol, an important constituent of both TTO and C + R mixture oils. FTNIR spectroscopy showed the modified shape of the second overtone bands belonging to methyl and methylene groups, between 8500 and 8000 cm-1. This confirmed the increased lipid disorders already observed by FTIR spectroscopy. The results obtained on the probe organism V. faba show that FTIR and FTNIR spectroscopy can become a useful support to the conventional cytogenetic tests used in the evaluation of the allelopathic uses of essential oils in agriculture.

Molecular and structural changes induced by essential oils treatments in Vicia faba roots detected by genotoxicity testing.

Over the last few years, there has been an increased interest in exploiting allelopathy in organic agriculture. The aim of this investigation was to examine the effects of essential oil mixtures in order to establish their allelopathic use in agriculture. Two mixtures of essential oils consisting respectively of tea tree oil (TTO) and clove plus rosemary (C + R) oils were tested. Phytotoxicity and genotoxicity tests on the root meristems of Vicia faba minor were performed. A phytotoxic influence was particularly relevant for C + R mixture, while genotoxicity tests revealed significant results with both C + R oil mixture and TTO. Phenotypic analysis on Vicia faba minor primary roots following C + R oil mixture treatment resulted in callose production, an early symptom attributed to lipid peroxidation. The approach described in this study, based on genotoxicity bioassays, might identify specific DNA damage induced by essential oil treatments. These tests may represent a powerful method to evaluate potential adverse effects of different mixtures of essential oils that might be useful in alternative agriculture. Future studies are focusing on the positive synergism of more complex mixtures of essential oils in order to reduce concentrations of potentially toxic components while at the same time maintaining efficacy in antimicrobial and antifungal management.

Arsenic exposure triggers a shift in microRNA expression.

Exposure to inorganic Arsenic (iAs) through drinking water is a major public health problem affecting most countries. iAs has been classified by the International Agency for Research on Cancer as Group 1: "Carcinogenic to humans". Although numerous studies have shown the related adverse effects of iAs, sensitive appropriate biomarkers for studies of environmental epidemiology are still required. The present work aims at investigate the role of microRNAs (miRNAs), powerful negative regulators of gene expression, playing a key role in many physiological and pathological cellular processes, in iAs exposure. To this end, we analyzed miRNA changes in expression profile triggered by iAs exposure in Jurkat cell line. We used microarray technology to profile the expression of miRNAs following 2 µmol/L sodium arsenite treatment at different time points. Moreover, we performed phenotypic analysis of iAs treated cells. Real Time Polymerase Chain Reaction (RT-PCR) was used to validate miRNA microarray data and to assay expression modulation of selected relevant mRNAs. Finally, bioinformatics techniques were applied to reconstruct iAs-relevant molecular pathways and miRNA regulatory networks from the expression data. We report miRNAs modulated after iAs treatment in Jurkat cells. In particular, we highlight 36 miRNAs exhibiting consistent dysregulation and particularly a panel of 8 miRNAs which we also validated by RT-PCR analysis. Computational analysis of lists of putative target genes for these 8 miRNAs points to an involvement in arsenic-response pathways, for a subset of them, that were analyzed by RT-PCR. Furthermore, iAs exposure reveals induction of cell cycle progression and the failure of apoptosis, supporting the idea of iAs carcinogenic activity. Our study provides a list of miRNAs whose expression levels are affected by iAs treatment, corroborating the importance of proceeding with the hunt for specific subset of miRNAs, which can serve as potential biomarkers of iAs effects with useful diagnostic value.