1,721,164 research outputs found
Simultaneous determination of shikimic acid, salicylic acid and jasmonic acid in wild and transgenic Nicotiana langsdorffii plants exposed to abiotic stresses
Full text linkThe presence and relative concentration of phytohormones may be regarded as a good indicator of an organism's physiological state. The integration of the rolC gene from Agrobacterium rhizogenes and of the rat glucocorticoid receptor (gr) in Nicotiana langsdorffii Weinmann plants has shown to determine various physiological and metabolic effects. The analysis of wild and transgenic N. langsdorffii plants, exposed to different abiotic stresses (high temperature, water deficit, and high chromium concentrations) was conducted, in order to investigate the metabolic effects of the inserted genes in response to the applied stresses. The development of a new analytical procedure was necessary, in order to assure the simultaneous determination of analytes and to obtain an adequately low limit of quantification. For the first time, a sensitive HPLC-HRMS quantitative method for the simultaneous determination of salicylic acid, jasmonic acid and shikimic acid was developed and validated. The method was applied to 80 plant samples, permitting the evaluation of plant stress responses and highlighting some metabolic mechanisms. Salicylic, jasmonic and shikimic acids proved to be suitable for the comprehension of plant stress responses. Chemical and heat stresses showed to induce the highest changes in plant hormonal status, differently affecting plant response. The potential of each genetic modification toward the applied stresses was marked and particularly the resistance of the gr modified plants was evidenced. This work provides new information in the study of N. langsdorffii and transgenic organisms, which could be useful for the further application of these transgene
Processes affecting the distribution of PCBs in the Southern Ocean
No full textPolychlorinated biphenyls (PCBs) are a broad class of globally distributed persistent pollutants that differ in their degree of chlorination and, thereby, in their volatility and are subject to long-range atmospheric transport (LRAT). Although their industrial production was discontinued in the early nineties, some PCB congeners are still released into the environment as unintentional by-products of dye manufacturing and other chemical productions. Among them, 3,3’-dichlorobiphenyl (PCB-11) has been detected at concentrations often higher than those of the other technical congeners (i.e. legacy Aroclor PCBs) in almost all the environmental compartments, even in polar areas (Choi et al., 2008).
It is known that the atmosphere plays a key role in transport and distribution of persistent organic pollutants (POPs) towards polar areas, through successive phases of volatilization and deposition that occur at the air/water interface. The low temperatures of the polar areas promote this partition between the atmosphere and the seawater surface via the cold trapping mechanism (Wania and MacKay, 1996). However, this process is reversible, so the partition of POPs moves in one direction or in the opposite one depending on the volatility of the molecules involved, their relative concentration in air and water, and changes in temperature (Galbán-Malagón et al., 2013).
As the surface water temperature decreases, lighter congeners, more prone to volatilization, tend instead to settle in the water surface layers. Indeed, in the Southern Ocean, where the temperature of surface water is reduced to values close to that of the air, a particularly high concentration of PCB-11 compared to that of other less volatile PCB congeners have been reported (Choi et al., 2008; Pizzini et al., 2017). Instead, PCBs with a higher degree of chlorination are less prone to volatilization in temperate areas and, consequently, they would be preferentially transferred to the Southern Ocean through Modified Circumpolar Deep waters (Fuoco et al., 2009) rather than via LRAT. Against this background, it can be assumed that more processes are involved in the transport of PCBs towards the Southern Ocean, depending on the characteristics of the investigated molecules and, primarily, their volatility.
In this work, the results of analyses of water samples collected along a transect from the Southern Pacific Ocean to the Ross Sea will be presented. Preliminary outcomes confirmed the hypothesis that more volatile PCBs reach the Southern Ocean preferentially through a cold condensation process, differently from heavier ones. Di- and Tri-chlorinated PCBs reached particularly high concentrations in water surface layers where there is a sharp decrease in temperature, in the Antarctic convergence zone, while this effect is much more limited for the less volatile investigated congeners.
Choi, S.-D., Baek, S.-Y., Chang, Y.-S., Wania, F., Ikonomou, M.G., Yoon, Y.-J., Park, B.-K., Hong, S., 2008. Passive Air Sampling of Polychlorinated Biphenyls and Organochlorine Pesticides at the Korean Arctic and Antarctic Research Stations: Implications for Long-Range Transport and Local Pollution. Environmental Science & Technology 42, 7125-7131. https://doi.org/10.1021/es801004p.
Fuoco, R., Giannarelli, S., Wei, Y., Ceccarini, A., Abete, C., Francesconi, S., Termine, M., 2009. Persistent organic pollutants (POPs) at Ross Sea (Antarctica). Microchemical Journal 92(1), 44-48. https://doi.org/10.1016/j.microc.2008.11.004.
Galbán-Malagón, C. J., Del Vento, S., Cabrerizo, A., Dachs, J., 2013. Factors affecting the atmospheric occurrence and deposition of polychlorinated biphenyls in the Southern Ocean. Atmospheric Chemistry and Physics 13, 12029-12041. https://doi.org/10.5194/acp-13-12029-2013.
Pizzini, S., Sbicego, C., Corami, F., Grotti, M., Magi, E., Bonato, T., Cozzi, G., Barbante, C., Piazza, R., 2017. 3,3’-dichlorobiphenyl (non-Aroclor PCB-11) as a marker of non-legacy PCB contamination in marine species: comparison between Antarctic and Mediterranean bivalves. Chemosphere 175, 28-35. https://doi.org/10.1016/j.chemosphere.2017.02.023.
Wania, F., MacKay, D., 1996. Tracking the Distribution of Persistent Organic Pollutants. Environmental Science & Technology 30(9), 390A-396A. https://doi.org/10.1021/es962399q
Nicotiana langsdorffiiwild type and genetically modified exposed to chemical and physical stress: changes in element content
No full textThe concentrations of 19 elements in wild and genetically modified Nicotiana langsdorffii
(N. langsdorffii) exposed to Chromium (VI) and to water deficit were determined and
compared to provide new information about their response to abiotic stress.
Genetic modifications by GR and RolC genes (encoding for the rat glucocorticoid receptor
and for Agrobacterium rhizogenes RolC, respectively) were investigated because they induce
significant, but only partially known changes in the plant response to stress.
Simultaneous determination of Al, As, Ba, Ca, Cd, Co, Cr, Cs, Cu, Fe, K, Mg, Mn, Na, Pb,
Rb, Sr, V and Zn was carried out by ICP-MS equipped with a collision/reaction cell (ICPORS-
MS). The methodology was optimised by testing the grinding, homogenisation, digestion
and analysis procedures, to reduce the uncertainty of the experimental results and to
identify statistically significant differences between nine sample pools, for a total of 75
samples. The quality control procedure was carried out by blank control and by evaluating
the detection limits and repeatability. Trueness was assessed by analysing certified reference
material, NIST 1573a.
Significant differences were observed in the uptake and accumulation of several elements
in the wild-type N. langsdorffii samples, either with respect to the plants submitted to water
deficit and exposure to Cr(VI) or with respect to the genetically modified plants. The
differences were highlighted by principal component analysis (PCA). The analysis of the
element content of the whole plant, combined with the data found in the literature, allows us
to hypothesise effects on the metabolic mechanism controlling the uptake and translocation of
elements inside the vegetal organism. Because genetic and chemical stress decreases the
nutrient concentration in the whole plant, we can say that the uptake at root level is affected.
The increase in concentration of elements such as As, Sr and Al indicates a decreased
selectivity in the uptake of potentially toxic elements and, consequently, highlights the effects
on the plant’s metabolic processes
A new exploration of licorice metabolome
No full textThe roots and rhizomes of licorice plants (genus Glycyrrhiza L.) are commercially employed, after processing, in confectionery production or as sweetening and flavouring agents in the food, tobacco and beer industries. G. glabra, G. inflata and G. uralensis are the most significant licorice species, often indistinctly used for different productions. Licorice properties are directly related to its chemical composition, which determines the commercial values and the quality of the derived products. In order to better understand the characteristics and properties of each species, a chemical characterization of three species of licorice (G. glabra, G. inflata, G. uralensis) is proposed, through an untargeted metabolomic approach and using high-resolution mass spectrometry. The statistical analysis reveals new possible markers for the analyzed species, and provides a reliable identification of a high number of metabolites, contributing to the characterization of Glycyrrhiza metabolome
Dissolved REEs in the western Ross Sea-Antarctica: geochemical tracers of the water masses
No full text
Effects of Water Deficit and Heat Stress on Nicotiana langsdorffii Metabolomic Pattern Modified by Insertion of rolD Gene from Agrobacterium rhizogenes
Full text linkAbiotic stresses are major factors that negatively affect plant growth and productivity. Plants have developed complex strategies to ensure their survival and reproduction under adverse conditions, activating mechanisms that involve changes at different metabolic levels. In order to select stress-resistant species, research has focused on molecular studies and genetic engineering, showing promising results. In this work, the insertion of the rolD gene from Agrobacterium rhizogenes into Nicotiana langsdorffii plants is investigated, in order to assess the potential of this genetic modification towards mitigating water and heat stresses. Different approaches were combined: a high-throughput metabolomics and ionomics study was performed, together with the determination of important plant phytohormones. The aim was to identify the influence of abiotic stresses on plants and to highlight the effects of the rolD genetic modification on plant stress response. The most relevant compounds for each kind of stress were identified, belonging mainly to the classes of lipids, acyl sugars, glycosides, and amino acid derivatives. Water stress (WS) determined a decrease of elements and secondary metabolites, while amino acids and their derivatives increased, proving to be key molecules in this type of stress. RolD plants exposed to high temperature stress (HS) presented higher dry weight levels than controls, as well as increased amounts of K and adenosine and lower levels of damage-associated metabolites, suggesting the increased resistance of rolD-modified plants toward HS.Abiotic stresses are major factors that negatively affect plant growth and productivity. Plants have developed complex strategies to ensure their survival and reproduction under adverse conditions, activating mechanisms that involve changes at different metabolic levels. In order to select stress-resistant species, research has focused on molecular studies and genetic engineering, showing promising results. In this work, the insertion of therolDgene fromAgrobacterium rhizogenesintoNicotiana langsdorffiiplants is investigated, in order to assess the potential of this genetic modification towards mitigating water and heat stresses. Different approaches were combined: a high-throughput metabolomics and ionomics study was performed, together with the determination of important plant phytohormones. The aim was to identify the influence of abiotic stresses on plants and to highlight the effects of therolDgenetic modification on plant stress response. The most relevant compounds for each kind of stress were identified, belonging mainly to the classes of lipids, acyl sugars, glycosides, and amino acid derivatives. Water stress (WS) determined a decrease of elements and secondary metabolites, while amino acids and their derivatives increased, proving to be key molecules in this type of stress. RolD plants exposed to high temperature stress (HS) presented higher dry weight levels than controls, as well as increased amounts of K and adenosine and lower levels of damage-associated metabolites, suggesting the increased resistance ofrolD-modified plants toward HS
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