Fisiologia delle piantine di orzo esposte allo stress da cadmio

I metalli pesanti sono importanti inquinanti ambientali e la loro tossicità è un problema di crescente importanza per motivi ecologici, evolutivi, nutrizionali e ambientali. Il cadmio (Cd) è, tra i metalli pesanti non essenziali, quello che ha attirato maggiormente l'attenzione nel campo della nutrizione delle piante, a causa della sua potenziale tossicità per l'uomo, e anche la sua relativa mobilità nel sistema suolo-pianta. Il progetto di dottorato si è proposto lo studio dei meccanismi di risposta - su base micro e macroscopica, fisiologica, ecologica e biochimica - allo stress da cadmio, su una pianta di elevato interesse agricolo ed economico: l’orzo (Hordeum vulgare). In particolare, sono stati osservati gli effetti causati dal cadmio su piantine d’orzo esposte alle concentrazioni di 10-6 M, 10-5 M e 10-4 M. Sono stati determinati la presenza di danni ultrastrutturali indotti dalla presenza del cadmio mediante microscopia elettronica a scansione (SEM) e a trasmissione (TEM), e relazionati alla presenza e alle variazioni delle varie isoforme (citosolica, cloroplastica e mitocondriale) di Heat Shock Protein 70 (HSP70), nelle radici e nelle foglie, dei campioni stressati. Inoltre, è stata determinata la presenza di alterazioni fenotipiche delle piantine d’orzo, sia a livello della componente epigea (numero di foglie, lunghezza e larghezza delle foglie) che della parte ipogea (lunghezza delle radici primarie e numero di radici secondarie). Dall’analisi macroscopica si osserva una modificazione dell’apparato radicale in funzione della concentrazione di cadmio, con la riduzione della lunghezza delle radici primarie e un maggior numero di radici secondarie, risultati confermati anche dalla microscopia elettronica a scansione. Sono stati misurati importanti parametri eco-fisiologici come la percentuale di inibizione della crescita, il contenuto di acqua (WC), il contenuto di pigmenti fotosintetici (clorofilla a, clorofilla b e carotenoidi) e il contenuto d’amido. Tali parametri solo stati relazionati con i principali indici fotochimici: massima resa quantica del PSII (Fv/Fm), resa quantica del trasporto elettronico del PSII (QY), attività di trasporto elettronico (ETR) e quenching non-fotochimico (NPQ),allo scopo di valutare l’effetto dei metalli sull’efficienza di conversione della luce ai centri di reazione. Il cadmio causa, inoltre, una inibizione della crescita con conseguente minore produzione di biomassa, di un minor contenuto d’acqua, di pigmenti fotosintesi e di amido e questi risultati sono collegati alle alterazioni macroscopiche come la minore lunghezza e la maggiore larghezza delle foglie. La riorganizzazione dell’apparato radicale induce la presenza di una maggior superficie di assorbimento dell’azoto con conseguente incremento dell’attività della nitrato reduttasi. Lo stress non ha effetti verso le proteine Rubisco e D1, confermando che il cadmio influisce nella biosintesi della clorofilla, sui centri di reazione e nella catena di trasporto degli elettroni del PSII. Tali risultati sono correlati alla presenza di danni ultrastrutturali a livello dei cloroplasti che presentano una disorganizzazione tilacoidale e l’inclusione di briglie citopaslamtiche. L’attività della glucosio-6-fostato deidrogenasi (G6PDH), sia in foglie che i radici, risulta essere lievemente ridotta dalla presenza degli ioni cadmio anche se i livelli, nelle foglie, della isoforma Cyt della G6PDH rimangono invariati, i livelli dell’isoforma P2 aumentano alla concentrazione Cd++ 10-4 M, mentre i livelli dell’isoforma P1 presentano un andamento contrario rispetto l’isoforma P2; inoltre, non si osservano variazioni significative delle isoforme Cyt e P2 a livello radicale. Il cadmio induce un severo stress abiotico confermato dall’incremento in funzione dell’aumento di concentrazione del metallo dei livelli delle varie isoforme HSP70 e da una loro diminuzione in funzione del tempo e dell’entità del danno osservato. Infine, il cadmio induce una evidente variazione del profilo amminoacidico delle piantine stressate. In conclusione, il cadmio è tra i metalli più tossici per le specie vegetali e sebbene l’orzo rappresenti un organismo coltivato tra i più resistenti agli stress abiotici, sono stati riscontrati danni evidenti sulla sfera micro e macroscopica, fisiologica, ecologica e biochimica

A Decision Support System for Land Allocation under Multiple Objectives in Public Production Forests in the Brazilian Amazon

Logging in natural forests is a vital economic activity in the Brazilian Amazon. However, illegal and unplanned logging is exhausting forests rapidly. In 2006, a new forestry law in Brazil (Lei 11,284/2006) established the legal framework to develop state and national public forests for multiple uses. To support public forest planning efforts, we combine spatially explicit data on logging profits, biodiversity, and potential for community use for use within a forest planning optimization model. While generating optimal land use configurations, the model enables an assessment of the market and nonmarket tradeoffs associated with different land use priorities. We demonstrate the model's use for Faro State Forest, a 636,000 ha forest embedded within a large mosaic of conservation units recently established in the state of Pará. The datasets used span the entire Brazilian Amazon, implying that the analysis can be repeated for any public forest planning effort within the region

Quantifying timber illegality risk in the Brazilian forest frontier

Illegal logging remains widespread across the tropics, leading to extensive forest degradation and trade in illegal timber products. By adapting environmentally extended input–output modelling to timber originating from Brazilian native forests, we demonstrate how distinct illegality risks can be mapped and quantified at species-level across the supply chain. We focus on high-value ip\uea hardwood from the Amazon state of Par\ue1, a leading producer of timber and contested forest frontier. Data on logging permits and state- and national-level Document of Forest Origin licences are used to estimate illegality risks due to missing or invalid logging permits, overstated ip\uea yields or discrepancies resulting from missing inflows of legal timber. We find that less than a quarter of all ip\uea entering supply chains between 2009 and 2019 is risk-free and highlight diversified strategies for the laundering of illegal timber across geographies. While legality does not ensure sustainability, this information can be leveraged to this end by supporting improved implementation and enforcement of forest regulations

Zn-biofortification enhanced nitrogen metabolism and photorespiration process in green leafy vegetable Lactuca sativa L

Abstract BACKGROUND: Excessive rates of nitrogen (N) fertilizers may result in elevated concentrations of nitrate (NO3 −) in plants. Considering thatmany programs of biofortification with trace elements are being performed, it has become important to study how the application of these elements affects plant physiology and, particularly, N utilization in leaf crops. The main objective of the present study was to determine whether the NO3 − accumulation and the nitrogen use efficiency was affected by the application of different doses of Zn in Lactuca sativa plants. RESULTS: Zn doses in the range 80–100 mol L−1 produced an increase in Zn concentration provoking a decrease of NO3 − concentration and increase of the nitrate reductase, glutamine synthetase and aspartate aminotransferase activities, as well as the photorespiration processes. As result, we observed an increase in reduced N, total N concentration and N utilization efficiency. Consequently, at a dose of 80 mol L−1 of Zn, the amino acid concentration increased significantly. CONCLUSION: Adequate Zn fertilization is an important critical player in lettuce, especially at a dose of 80 mol L−1 of Zn, because it could result in an increase in the Zn concentration, a reduction of NO3 − levels and an increase the concentration of essential amino acids, with all of them having beneficial properties for the human diet

Improving the Performance of the Prony Method Using a Wavelet Domain Filter for MRI Denoising

The Prony methods are used for exponential fitting. We use a variant of the Prony method for abnormal brain tissue detection in sequences of T2 weighted magnetic resonance images. Here, MR images are considered to be affected only by Rician noise, and a new wavelet domain bilateral filtering process is implemented to reduce the noise in the images. This filter is a modification of Kazubek’s algorithm and we use synthetic images to show the ability of the new procedure to suppress noise and compare its performance with respect to the original filter, using quantitative and qualitative criteria. The tissue classification process is illustrated using a real sequence of T2 MR images, and the filter is applied to each image before using the variant of the Prony method

Glucose-6-phosphate dehydrogenase plays a central role in the response of tomato (Solanum lycopersicum) plants to short and long-term drought

The present study was undertaken to investigate the expression, occurrence and activity of glucose 6 phosphate dehydrogenase (G6PDH e EC 1.1.1.49), the key-enzyme of the Oxidative Pentose Phosphate Pathway (OPPP), in tomato plants (Solanum lycopersicum cv. Red Setter) exposed to short- and long-term drought stress. For the first time, drought effects have been evaluated in plants under different growth conditions: in hydroponic laboratory system, and in greenhouse pots under controlled conditions; and in open field, in order to evaluate drought response in a representative agricultural environment. Interestingly, changes observed appear strictly associated to the induction of well known stress response mechanisms, such as the increase of proline synthesis, accumulation of chaperone Hsp70, and ascorbate peroxidase. Results show significant increase in total activity of G6PDH, and specifically in expression and occurrence of cytosolic isoform (cy-G6PDH) in plants grown in any cultivation system upon drought. Intriguingly, the results clearly suggest that abscissic acid (ABA) pathway and signaling cascade (protein phosphatase 2C e PP2C) could be strictly related to increased G6PDH expression, occurrence and activities. We hypothesized for G6PDH a specific role as one of the main reductants’ suppliers to counteract the effects of drought stress, in the light of converging evidences given by young and adult tomato plants under stress of different duration and intensity

Investigating the inhibition of FTSJ1 a tryptophan tRNA-specific 2’-O-methyltransferase by NV TRIDs, as a mechanism of readthrough in nonsense mutated CFTR

Abstract: Cystic Fibrosis (CF) is an autosomal recessive genetic disease caused by mutations in the CFTR gene, coding for the CFTR chloride channel. About 10% of the CFTR gene mutations are "stop" mutations, which generate a Premature Termination Codon (PTC), thus synthesizing a truncated CFTR protein. A way to bypass PTC relies on ribosome readthrough, which is the ri-bosome’s capacity to skip a PTC, thus generating a full-length protein. “TRIDs” are molecules exerting ribosome readthrough; for some, the mechanism of action is still under debate. We in-vestigate a possible mechanism of action (MOA) by which our recently synthesized TRIDs, namely NV848, NV914, and NV930, could exert their readthrough activity by in silico analysis and in vitro studies. Our results suggest a likely inhibition of FTSJ1, a tryptophan tRNA-specific 2’-O-methyltransferase

Effectiveness of polymyxin B-immobilized fiber column in sepsis: a systematic review

INTRODUCTION: Severe sepsis and septic shock are common problems in the intensive care unit and carry a high mortality. Endotoxin, one of the principal components on the outer membrane of gram-negative bacteria, is considered important to their pathogenesis. Polymyxin B bound and immobilized to polystyrene fibers (PMX-F) is a medical device that aims to remove circulating endotoxin by adsorption, theoretically preventing the progression of the biological cascade of sepsis. We performed a systematic review to describe the effect in septic patients of direct hemoperfusion with PMX-F on outcomes of blood pressure, use of vasoactive drugs, oxygenation, and mortality reported in published studies. METHODS: We searched PubMed, the Cochrane Collaboration Database, and bibliographies of retrieved articles and consulted with experts to identify relevant studies. Prospective and retrospective observational studies, pre- and post-intervention design, and randomized controlled trials were included. Three authors reviewed all citations. We identified a total of 28 publications - 9 randomized controlled trials, 7 non-randomized parallel studies, and 12 pre-post design studies - that reported at least one of the specified outcome measures (pooled sample size, 1,425 patients: 978 PMX-F and 447 conventional medical therapy). RESULTS: Overall, mean arterial pressure (MAP) increased by 19 mm Hg (95% confidence interval [CI], 15 to 22 mm Hg; p < 0.001), representing a 26% mean increase in MAP (range, 14% to 42%), whereas dopamine/dobutamine dose decreased by 1.8 microg/kg per minute (95% CI, 0.4 to 3.3 microg/kg per minute; p = 0.01) after PMX-F. There was significant intertrial heterogeneity for these outcomes (p < 0.001), which became non-significant when analysis was stratified for baseline MAP. The mean arterial partial pressure of oxygen/fraction of inspired oxygen (PaO2/FiO2) ratio increased by 32 units (95% CI, 23 to 41 units; p < 0.001). PMX-F therapy was associated with significantly lower mortality risk (risk ratio, 0.53; 95% CI, 0.43 to 0.65). The trials assessed had suboptimal method quality. CONCLUSION: Based on this critical review of the published literature, direct hemoperfusion with PMX-F appears to have favorable effects on MAP, dopamine use, PaO2/FiO2 ratio, and mortality. However, publication bias and lack of blinding need to be considered. These findings support the need for further rigorous study of this therapy

Readthrough Approach Using NV Translational Readthrough-Inducing Drugs (TRIDs): A Study of the Possible Off-Target Effects on Natural Termination Codons (NTCs) on TP53 and Housekeeping Gene Expression

Nonsense mutations cause several genetic diseases such as cystic fibrosis, Duchenne muscular dystrophy, β-thalassemia, and Shwachman–Diamond syndrome. These mutations induce the formation of a premature termination codon (PTC) inside the mRNA sequence, resulting in the synthesis of truncated polypeptides. Nonsense suppression therapy mediated by translational readthrough-inducing drugs (TRIDs) is a promising approach to correct these genetic defects. TRIDs generate a ribosome miscoding of the PTC named “translational readthrough” and restore the synthesis of full-length and potentially functional proteins. The new oxadiazole-core TRIDs NV848, NV914, and NV930 (NV) showed translational readthrough activity in nonsense-related in vitro systems. In this work, the possible off-target effect of NV molecules on natural termination codons (NTCs) was investigated. Two different in vitro approaches were used to assess if the NV molecule treatment induces NTC readthrough: (1) a study of the translational-induced p53 molecular weight and functionality; (2) the evaluation of two housekeeping proteins’ (Cys-C and β2M) molecular weights. Our results showed that the treatment with NV848, NV914, or NV930 did not induce any translation alterations in both experimental systems. The data suggested that NV molecules have a specific action for the PTCs and an undetectable effect on the NTCs