Elena Sturchio

The essential oils in agriculture as an alternative strategy to herbicides: a case study

In this study we investigated the allelopathic effect of some essential oils extracted from aromatic plants to inhibit weed seed germination. The study was performed to evaluate the potential genotoxic effect of lavender on Vicia faba root meristems by genotoxicity tests (comet assay and micronuclei test) and to evaluate microbial diversity fluctuation by Restriction Fragment Length Polymorphism (RFLP) molecular analysis on ecological, biological and conventional soil. The results showed a phytotoxicity effect of the essential oil for all the concentration tested, while there is not a dose-dependent relation between oil concentrations and the genotoxic effect. A fluctuation of microbial communities in relation to the release of essential oils by Lavandula officinalis was also observed. Then we suggest that the essential oils could be useful as potential bioherbicides as an alternative strategy to the chemical remedy, but further studies are necessary to evaluate their appropriate use in the field.

Effects of arsenic on soil–plant systems

Arsenic is a highly toxic element and its presence in food composites is a matter of concern for the well-being of both humans and animals. The aim of this study was to evaluate the effects of arsenic on food vegetables and polluted soils. Vicia faba seedlings grown on polluted soils were used to evaluate the phytotoxic and genotoxic effects by comet assay. The results of these tests were dependent upon different types of soils. We studied different types of soils and contamination effects on Raphanus sativus L. and Lactuca sativa L. cropping by using magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR). For both analytical approaches, we found indicators correlated to As contamination, chemical for NMR, i.e. modification of composition, and morphological for MRI, i.e reorganisation of internal tissues. Samples of vegetables were collected to analyse their micro- and macronutrient contents and level of metals using inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis, which confirms the results obtained by MRI.

Molecular modifications induced by inorganic arsenic in Vicia faba investigated by FTIR, FTNIR spectroscopy and genotoxicity testing.

Exposure to inorganic arsenic (iAs) through drinking water is a major public health concern affecting most countries. Epidemiologic studies showed a significant association between consumption of iAs through drinking water and different types of cancer. However, the exact mechanisms underlying As-induced cancer and other diseases are not yet well understood. The aim of this study is to determine the effects of exposure iAs (20 or 30 mg/L) on Vicia faba seedlings in terms of phytotoxicity, genotoxicity, and spectroscopy by investigation of molecular modifications using infrared (FTIR) and near infrared (FTNIR) spectroscopy. Further, the mitigation effects of a precursor of glutathione (GSH), N-acetylcysteine (NAC), were also assessed. Spectroscopic and genotoxicity analysis demonstrated that specific molecular changes were directly correlated with iAs exposure. Comet assay in Vicia faba showed significant effects at concentrations of 20 and 30 mg/L, depending on the structural changes involving nucleic acids as identified by FTIR and FTNIR spectroscopy. Results of phytotoxicity and micronuclei tests were significant only at higher iAs concentrations (30 mg/L), where an antioxidant effect of NAC was noted. The two spectroscopic techniques demonstrated molecular modifications predominantly associated with chemical interactions of iAs with biomolecules such as nucleic acids, carbohydrates, lipids, and proteins in Vicia faba. Our findings suggest that further studies are required to better understand the mechanisms underlying toxicity produced by different As chemical forms in vegetal and agricultural species.

Development of biomarkers in an integrated approach to environmental studies

This study was conducted in a contained environment in order to develop biomarkers and to evaluate the environmental damage after a release of two different toxic substances which are widely used in industrial production. In a simulation study performed in Tor Mancina area (near Rome, Italy), two dangerous substances (formaldehyde and bromine) were tested. Chemical and physical characterisation, nutritive and organic contents, and trace elements presence were also investigated. The contamination effects on soil functional qualities and plant nutrition were evaluated; furthermore DNA damage with short-term genotoxicity tests and DNA biosensor on polluted soils and gravitational water, was detected. The genotoxic effects were evaluated on Vicia faba seedlings by two different short-term tests: comet assay and micronuclei test. A DNA-based biosensor for the detection of genotoxic compounds in soil samples was assembled by immobilising double stranded calf thymus DNA on screen-printed electrodes. An agreement between the comet assay and the other methodologies was observed. The results showed that the nature and the concentration of the two substances result in different molecular interaction with exposed environment. Furthermore, some of the chemical physical parameters considered are applicable indicators for the evaluation of the soil?plant system pollution.

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

ABSTRACT 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.

Computer Assisted Examination of Infrared and Near Infrared Spectra to Assess Structural and Molecular Changes in Biological Samples Exposed to Pollutants: A Case of Study

We present a computer assisted method for the examination of the structural changes present in the probe organism Vicia faba exposed to inorganic arsenic, detected by means of Fourier transform infrared (FTIR) and Fourier transform near infrared (FTNIR) spectroscopy. Like the common ecotoxicological tests, the method is based on the comparison among control and exposed sample spectra of the organisms to detect structural changes caused by pollutants. Using FTIR spectroscopy, we measured and plotted the spectral changes related to the unsaturated to saturated lipid ratio changes (USL), the lipid to protein ratio changes (LPR), fatty and ester fatty acid content changes (FA), protein oxidation (PO) and denaturation, and DNA and RNA changes (DNA-RNA). Using FTNIR spectroscopy, we measured two spectral ranges that belonged to hydrogen bond interactions and aliphatic lipid chains called IntHCONH and Met1overt, respectively. The FTIR results showed that As modified the DNA-RNA ratio and also caused partial protein denaturation in the Vicia faba samples. The FTNIR results supported the FTIR results. The main advantage of the proposed computational method is that it does not require a skilled infrared or near infrared operator, lending support to conventional studies performed by toxicological testing.