α-Chitosan and ß-Oligochitosan Mixtures-Based Formula for In Vitro Assessment of Melanocyte Cells Response.

Chitosan is a natural polymer with numerous biomedical applications. The cellular activity of chitosan has been studied in various types of cancer, including melanoma, and indicates that these molecules can open new perspectives on antiproliferative action and anticancer therapy. This study analyzes how different chitosan conformations, such as α-chitosan (CH) or ß-oligochitosan (CO), with various degrees of deacetylation (DDA) and molar mass (MM), both in different concentrations and in CH-CO mixtures, influence the cellular processes of SK-MEL-28 melanocytes, to estimate the reactivity of these cells to the applied treatments. The in vitro evaluation was carried out, aiming at the cellular metabolism (MTT assay), cellular morphology, and chitinase-like glycoprotein YKL-40 expression. The in vitro effect of the CH-CO mixture application on melanocytes is obvious at low concentrations of α-chitosan/ß-oligochitosan (1:2 ratio), with the cell's response supporting the hypothesis that ß-oligo-chitosan amplifies the effect. This oligochitosan mixture, favored by the ß conformation and its small size, penetrates faster into the cells, being more reactive when interacting with some cellular components. Morphological effects expressed by the loss of cell adhesion and the depletion of YKL-40 synthesis are significant responses of melanocytes. ß-oligochitosan (1.5 kDa) induces an extension of cytophysiological effects and limits the cell viability compared to α-chitosan (400-900 kDa). Statistical analysis using multivariate techniques showed differences between the CH samples and CH-CO mixtures.

Elevated pretreatment lactate dehydrogenase and albumin-to-alkaline phosphatase ratio predict poor prognosis and early treatment discontinuation in head and neck cancer patients with preexistent diabetes mellitus.

Increased serum lactate dehydrogenase (LDH) activity is considered as a marker of cellular necrosis and serves as a metabolomic diagnostic marker in several types of cancer including head and neck squamous cell carcinoma (HNSCC). LDH, an enzyme involved in the glycolytic cycle, is correlated not only with the activation of oncogenes such as HIF-α and Myc, but also with effects such as tumor proliferation and metastasis. Serum alkaline phosphatase (ALP) is a marker of cell differentiation and tumor induction. Albumin-to-alkaline phosphatase ratio (AAPR) could be an advantageous biomarker due to its easily accessible dynamics and cost-effectiveness. Elevated values of AAPR could be associated with longer overall survival (OS) in cases with solid tumors. Diabetes mellitus (DM) could influence the outcome of patients with HNSCC by contributing to insulin resistance and chronic inflammation, and by being involved in various aspects of carcinogenesis, disease progression and metastasis. However, the use of antihyperglycemic medications (metformin) can have beneficial effects by inhibiting tumor metabolic pathways. The biomarker role of LDH and AAPR in HNSCC patients with DM has been less evaluated. The purpose of the study was to assess the prognostic value of pretreatment serum lactate dehydrogenase (LDH) and albumin-to-alkaline phosphatase ratio (AAPR) in predicting the duration of non-surgical oncological treatment and glycemic control in cases of head and neck cancers patients with DM, including cases selected from the database of the oncology clinic and oncology outpatient clinic of the Craiova County Hospital. Both LDH and AAPR can be used as pre-treatment biomarkers predictive of treatment response, or prognostic tools included in complex multi-parametric models in HNC associated with DM. However, given the impact of short-term glycemic control on the LDH level, it is necessary to evaluate these biomarkers after assessing and controlling for DM, and with the recommended cut-off value set around 0.5. Due to the limited number of cases, it is necessary to validate the results in multicentric trials with a larger number of patients (Tab. 5, Ref. 50). Keywords: diabetes mellitus, HNC, LDH, AAPR, biomarkers, predictive, head and neck cancers, lactate dehydrogenase, albumin-to-alkaline phosphatase ratio.

Amnio acid substitution at position 298 of human glucose-6 phosphatase-α significantly impacts its stability in mammalian cells.

Glucose-6-phosphatase-α (G6Pase-α) catalyzes the hydrolysis of glucose-6-phosphate to glucose and functions as a key regulator in maintaining blood glucose homeostasis. Deficiency in G6Pase-α causes glycogen storage disease 1a (GSD1a), an inherited disorder characterized by life-threatening hypoglycemia and other long-term complications. We have developed a potential mRNA-based therapy for GSD1a and demonstrated that a human G6Pase-α (hG6Pase-α) variant harboring a single serine (S) to cysteine (C) substitution at the amino acid site 298 (S298C) had > twofold increase in protein expression, resulting in improved in vivo efficacy. Here, we sought to investigate the mechanisms contributing to the increased expression of the S298C variant. Mutagenesis of hG6Pase-α identified distinct protein variants at the 298 amino acid position with substantial reduction in protein expression in cultured cells. Kinetic analysis of expression and subcellular localization in mammalian cells, combined with cell-free in vitro translation assays, revealed that altered protein expression stemmed from differences in cellular protein stability rather than biosynthetic rates. Site-specific mutagenesis studies targeting other cysteines of the hG6Pase-α S298C variant suggest the observed improvements in stability are not due to additional disulfide bond formation. The glycosylation at Asparagine (N)-96 is critical in maintaining enzymatic activity and mutations at position 298 mainly affected glycosylated forms of hG6Pase-α. Finally, proteasome inhibition by lactacystin improved expression levels of unstable hG6Pase-α variants. Taken together, these data uncover a critical role for a single amino acid substitution impacting the stability of G6Pase-α and provide insights into the molecular genetics of GSD1a and protein engineering for therapeutic development.

Narrative Review: Update on the Molecular Diagnosis of Fragile X Syndrome.

The diagnosis and management of fragile X syndrome (FXS) have significantly improved in the last three decades, although the current diagnostic techniques are not yet able to precisely identify the number of repeats, methylation status, level of mosaicism, and/or the presence of AGG interruptions. A high number of repeats (>200) in the fragile X messenger ribonucleoprotein 1 gene (FMR1) results in hypermethylation of promoter and gene silencing. The actual molecular diagnosis is performed using a Southern blot, TP-PCR (Triplet-Repeat PCR), MS-PCR (Methylation-Specific PCR), and MS-MLPA (Methylation-Specific MLPA) with some limitations, with multiple assays being necessary to completely characterise a patient with FXS. The actual gold standard diagnosis uses Southern blot; however, it cannot accurately characterise all cases. Optical genome mapping is a new technology that has also been developed to approach the diagnosis of fragile X syndrome. Long-range sequencing represented by PacBio and Oxford Nanopore has the potential to replace the actual diagnosis and offers a complete characterization of molecular profiles in a single test. The new technologies have improved the diagnosis of fragile X syndrome and revealed unknown aberrations, but they are a long way from being used routinely in clinical practice.

Implications of diabetes in head and neck cancer - A single center real-world data.

Diabetes mellitus (DM) and altered glucose metabolism have been associated with carcinogenesis, but also with prognosis and tolerance to treatment in different types of cancer. Head and neck cancers (HNC), the sixth most common malignancy worldwide, require a multimodal approach, especially in advanced stages and cancer specific treatment is often associated with therapeutic failure and severe toxicities even if it is delivered according to current standards. The aim of the study was to evaluate the clinical, biological and outcomes implications of DM in patients with HNC. The cases diagnosed with HNC associated with DM between January 2008 and December 2016 were selected from the database of the oncology clinic and the oncology outpatient clinic of the Craiova County Hospital. Under the limits of a relatively reduced patient lot of 23 cases, certain particular aspects of these cases are highlighted possibly due to the association of DM with HNC. This category of patients should not be treated differently even if a precaution is necessary due to the increased risk of complications related to treatment. The use of Metformin could bring outcome benefit and the treatment of DM with insulin could be associated with a worst prognostic. The use of poly-chemotherapy regimens (platinum double or triple combination including platinum salts) demonstrates the feasibility of using chemotherapy for these subtypes of patients. A tendency to de-escalate the treatment by omitting radiotherapy for this category of patients should also be noted. Neutrophil to lymphocyte ratio (NLR), a less specific biomarker could be less useful than the Glasgow Prognostic Score (GPS) which can be considered an accessible biomarker. A large percent of sinonasal cancers compared to the data reported in the literature could be also related to DM. Both this possible association and the benefit of Metformin and 5-Flurouracil must be reevaluated in studies in larger groups of patients (Ref. 25). Keywords: diabetes, head and neck cancers, metformin, toxicity, outcomes, chemotherapy.

Cold Atmospheric Plasma-Activated Media Improve Paclitaxel Efficacy on Breast Cancer Cells in a Combined Treatment Model.

The use of plasma-activated media (PAM), an alternative to direct delivery of cold atmospheric plasma to cancer cells, has recently gained interest in the plasma medicine field. Paclitaxel (PTX) is used as a chemotherapy of choice for various types of breast cancers, which is the leading cause of mortality in females due to cancer. In this study, we evaluated an alternative way to improve anti-cancerous efficiency of PTX by association with PAM, the ultimate achievement being a better outcome in killing tumoral cells at smaller doses of PTX. MCF-7 and MDA-MB-231 cell lines were used, and the outcome was measured by cell viability (MTT assay), the survival rate (clonogenic assay), apoptosis occurrence, and genotoxicity (COMET assay). Treatment consisted of the use of PAM in combination with under IC50 doses of PTX in short- and long-term models. The experimental data showed that PAM had the capacity to improve PTX's cytotoxicity, as viability of the breast cancer cells dropped, an effect maintained in long-term experiments. A higher frequency of apoptotic, dead cells, and DNA fragmentation was registered in cells treated with the combined treatment as compared with those treated only with PT. Overall, PAM had the capacity to amplify the anti-cancerous effect of PTX.

Capabilities and limits of autoencoders for extracting collective variables in atomistic materials science.

Free energy calculations in materials science are routinely hindered by the need to provide reaction coordinates that can meaningfully partition atomic configuration space, a prerequisite for most enhanced sampling approaches. Recent studies on molecular systems have highlighted the possibility of constructing appropriate collective variables directly from atomic motions through deep learning techniques. Here we extend this class of approaches to condensed matter problems, for which we encode the finite temperature collective variable by an iterative procedure starting from 0 K features of the energy landscape i.e. activation events or migration mechanisms given by a minimum - saddle point - minimum sequence. We employ the autoencoder neural networks in order to build a scalar collective variable for use with the adaptive biasing force method. Particular attention is given to design choices required for application to crystalline systems with defects, including the filtering of thermal motions which otherwise dominate the autoencoder input. The machine-learning workflow is tested on body-centered cubic iron and its common defects, such as small vacancy or self-interstitial clusters and screw dislocations. For localized defects, excellent collective variables as well as derivatives, necessary for free energy sampling, are systematically obtained. However, the approach has a limited accuracy when dealing with reaction coordinates that include atomic displacements of a magnitude comparable to thermal motions, e.g. the ones produced by the long-range elastic field of dislocations. We then combine the extraction of collective variables by autoencoders with an adaptive biasing force free energy method based on Bayesian inference. Using a vacancy migration as an example, we demonstrate the performance of coupling these two approaches for simultaneous discovery of reaction coordinates and free energy sampling in systems with localized defects.

Borrowing the Features of Biopolymers for Emerging Wound Healing Dressings: A Review.

Wound dressing design is a dynamic and rapidly growing field of the medical wound-care market worldwide. Advances in technology have resulted in the development of a wide range of wound dressings that treat different types of wounds by targeting the four phases of healing. The ideal wound dressing should perform rapid healing; preserve the body's water content; be oxygen permeable, non-adherent on the wound and hypoallergenic; and provide a barrier against external contaminants-at a reasonable cost and with minimal inconvenience to the patient. Therefore, choosing the best dressing should be based on what the wound needs and what the dressing does to achieve complete regeneration and restoration of the skin's structure and function. Biopolymers, such as alginate (ALG), chitosan (Cs), collagen (Col), hyaluronic acid (HA) and silk fibroin (SF), are extensively used in wound management due to their biocompatibility, biodegradability and similarity to macromolecules recognized by the human body. However, most of the formulations based on biopolymers still show various issues; thus, strategies to combine them with molecular biology approaches represent the future of wound healing. Therefore, this article provides an overview of biopolymers' roles in wound physiology as a perspective on the development of a new generation of enhanced, naturally inspired, smart wound dressings based on blood products, stem cells and growth factors.

18F-FDG PET/MRI Imaging in a Preclinical Rat Model of Cardiorenal Syndrome-An Exploratory Study.

Cardiorenal syndrome (CRS) denotes the bidirectional interaction of chronic kidney disease and heart failure with an adverse prognosis but with a limited understanding of its pathogenesis. This study correlates biochemical blood markers, histopathological and immunohistochemistry features, and 2-deoxy-2-fluoro-D-glucose positron emission tomography (18F-FDG PET) metabolic data in low-dose doxorubicin-induced heart failure, cardiorenal syndrome, and renocardiac syndrome induced on Wistar male rats. To our knowledge, this is the first study that investigates the underlying mechanisms for CRS progression in rats using 18F-FDG PET. Clinical, metabolic cage monitoring, biochemistry, histopathology, and immunohistochemistry combined with PET/MRI (magnetic resonance imaging) data acquisition at distinct points in the disease progression were employed for this study in order to elucidate the available evidence of organ crosstalk between the heart and kidneys. In our CRS model, we found that chronic treatment with low-dose doxorubicin followed by acute 5/6 nephrectomy incurred the highest mortality among the study groups, while the model for renocardiac syndrome resulted in moderate-to-high mortality. 18F-FDG PET imaging evidenced the doxorubicin cardiotoxicity with vascular alterations, normal kidney development damage, and impaired function. Given the fact that standard clinical markers were insensitive to early renal injury, we believe that the decreasing values of the 18F-FDG PET-derived renal marker across the groups and, compared with their age-matched controls, along with the uniform distribution seen in healthy developing rats, could have a potential diagnostic and prognostic yield in cardiorenal syndrome.

Chemical Composition, Antioxidant and Antiproliferative Activities of Taraxacum officinale Essential Oil.

Taraxacum officinale (TO) has been historically used for medicinal purposes due to its biological activity against specific disorders. To investigate the antioxidant and the antiproliferativepotential of TO essential oil in vitro and in vivo, the chemical composition of the essential oil was analyzed by GC-MS. The in vivo antioxidant capacity was assessed on liver and kidney homogenate samples from mice subjected to acetaminophen-induced oxidative stress and treated with TO essential oil (600 and 12,000 mg/kg BW) for 14 days. The in vitro scavenging activity was assayed using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and the reducing power methods. The cytotoxic effects against the HeLa cancer cell line were analyzed. The GC-MS analysis showed the presence of 34 compounds, 8 of which were identified as major constituents. The TO essential oil protected mice's liver and kidneys from acetaminophen-induced oxidative stress by enhancing antioxidant enzymes (catalase, superoxide dismutase, and glutathione) and lowering malondialdehyde levels. In vitro, the TO essential oil demonstrated low scavenging activity against DPPH (IC50 = 2.00 ± 0.05 mg/mL) and modest reducing power (EC50 = 0.963 ± 0.006 mg/mL). The growth of the HeLa cells was also reduced by the TO essential oil with an inhibition rate of 83.58% at 95 µg/mL. Current results reveal significant antioxidant and antiproliferative effects in a dose-dependent manner and suggest that Taraxacum officinale essential oil could be useful in formulations for cancer therapy.

Takotsubo Cardiomyopathy and ß-Blocker Poisoning: A Case Report.

ß-blocker poisoning is frequently observed because of its primary use for the treatment of cardiovascular diseases. The management of ß-blocker toxicity is dependent on the cardiovascular response and the severity of presentation. The present study describes the case of a patient with combined drug intoxication, ß-blocker, digoxin, benzodiazepines, acetaminophen and opiates in a suicidal attempt. A 63-year-old female was found somnolent and in a confused state at her residence following intentional poly-drug ingestion. Upon presentation, she was found to be hemodynamically unstable and was thus treated with vasopressors. The toxicological screening performed upon presentation was positive for polydrug ingestion. On day 3, the patient developed chest pain and ST-segment elevation in anterior leads, while transthoracic echocardiographic assessment disclosed a non-dilated left ventricle with moderate dysfunction and akinesia of the apex. Coronary angiogram revealed normal coronary arteries and, subsequently, the diagnosis of Takotsubo cardiomyopathy (TTC) was suspected. Supportive treatment was initiated with favorable evolution and left ventricular ejection fraction normalization. The management of hemodynamic instability with vasopressors should be judiciously administered in the treatment of ß-blocker poisoning, in view of the adverse effects on cardiac functions, including stress cardiomyopathy.

Quantum de-trapping and transport of heavy defects in tungsten.

The diffusion of defects in crystalline materials1 controls macroscopic behaviour of a wide range of processes, including alloying, precipitation, phase transformation and creep2. In real materials, intrinsic defects are unavoidably bound to static trapping centres such as impurity atoms, meaning that their diffusion is dominated by de-trapping processes. It is generally believed that de-trapping occurs only by thermal activation. Here, we report the direct observation of the quantum de-trapping of defects below around one-third of the Debye temperature. We successfully monitored the de-trapping and migration of self-interstitial atom clusters, strongly trapped by impurity atoms in tungsten, by triggering de-trapping out of equilibrium at cryogenic temperatures, using high-energy electron irradiation and in situ transmission electron microscopy. The quantum-assisted de-trapping leads to low-temperature diffusion rates orders of magnitude higher than a naive classical estimate suggests. Our analysis shows that this phenomenon is generic to any crystalline material.

Paclitaxel-Loaded Magnetic Nanoparticles Based on Biotinylated N-Palmitoyl Chitosan: Synthesis, Characterization and Preliminary In Vitro Studies.

A considerable interest in cancer research is represented by the development of magnetic nanoparticles based on biofunctionalized polymers for controlled-release systems of hydrophobic chemotherapeutic drugs targeted only to the tumor sites, without affecting normal cells. The objective of the paper is to present the synthesis and in vitro evaluation of the nanocomposites that include a magnetic core able to direct the systems to the target, a polymeric surface shell that provides stabilization and multi-functionality, a chemotherapeutic agent, Paclitaxel (PTX), and a biotin tumor recognition layer. To our best knowledge, there are no studies concerning development of magnetic nanoparticles obtained by partial oxidation, based on biotinylated N-palmitoyl chitosan loaded with PTX. The structure, external morphology, size distribution, colloidal and magnetic properties analyses confirmed the formation of well-defined crystalline magnetite conjugates, with broad distribution, relatively high saturation magnetization and irregular shape. Even if the ability of the nanoparticles to release the drug in 72 h was demonstrated, further complex in vitro and in vivo studies will be performed in order to validate the magnetic nanoparticles as PTX delivery system.

Severe Coronary Artery Disease in a Person Living with HIV.

The pathophysiology of accelerated atherosclerosis in people living with Human Immunofediciency virus (HIV) is complex. Coronary artery disease (CAD) has become an important cause of mortality in these patients. They often have atypical symptoms, leading to frequently missed diagnoses. We report a case of a 51-year-old male undergoing antiretroviral therapy who was admitted for acute coronary syndrome. He had severe coronary artery disease that involved difficult management.

mRNA Therapy Improves Metabolic and Behavioral Abnormalities in a Murine Model of Citrin Deficiency.

Citrin deficiency is an autosomal recessive disorder caused by loss-of-function mutations in SLC25A13, encoding the liver-specific mitochondrial aspartate/glutamate transporter. It has a broad spectrum of clinical phenotypes, including life-threatening neurological complications. Conventional protein replacement therapy is not an option for these patients because of drug delivery hurdles, and current gene therapy approaches (e.g., AAV) have been hampered by immunogenicity and genotoxicity. Although dietary approaches have shown some benefits in managing citrin deficiency, the only curative treatment option for these patients is liver transplantation, which is high-risk and associated with long-term complications because of chronic immunosuppression. To develop a new class of therapy for citrin deficiency, codon-optimized mRNA encoding human citrin (hCitrin) was encapsulated in lipid nanoparticles (LNPs). We demonstrate the efficacy of hCitrin-mRNA-LNP therapy in cultured human cells and in a murine model of citrin deficiency that resembles the human condition. Of note, intravenous (i.v.) administration of the hCitrin-mRNA resulted in a significant reduction in (1) hepatic citrulline and blood ammonia levels following oral sucrose challenge and (2) sucrose aversion, hallmarks of hCitrin deficiency. In conclusion, mRNA-LNP therapy could have a significant therapeutic effect on the treatment of citrin deficiency and other mitochondrial enzymopathies with limited treatment options.

Evaluation of the Cytotoxic Activity of the Usnea barbata (L.) F. H. Wigg Dry Extract.

The secondary metabolites of lichens have proven to be promising sources of anticancer drugs; one of the most important of these is usnic acid, which is a phenolic compound with dibenzofuran structure that is responsible for the numerous biological actions of lichens of genus Usnea. As a result, in this study, we related to this phenolic secondary metabolite. The aim of the present study is the evaluation of the cytotoxic activity of Usnea barbata (L.) F. H. Wigg dry acetone extract (UBE). In advance, the usnic acid content was determined in various extracts of Usnea barbata (L.) F. H. Wigg: the liquid extracts were found in water, ethanol, acetone, and the dry acetone extract; the highest usnic acid quantity was found in the dry acetone extract. First, the cytotoxic action of UBE was assessed using Brine Shrimp Lethality (BSL) test; a significant lethal effect was obtained after 24 h of treatment at high used concentrations of UBE, and it was quantified by the high mortality rate of the Artemia salina (L.) larvae. Secondly, in vitro cytotoxicity of UBE was evaluated on human tongue squamous cells carcinoma, using CAL 27 (ATCC® CRL-2095™) cell line. The most intense cytotoxic effect of UBE on CAL 27 cells was registered after 24 h; this response is directly proportional with the tested UBE concentrations. The obtained results have been reported regarding usnic acid content of UBE, and the data show that CAL 27 cells death was induced by apoptosis and high oxidative stress.

Stearic Acid/Layered Double Hydroxides Composite Thin Films Deposited by Combined Laser Techniques.

We report on the investigation of stearic acid-layered double hydroxide (LDH) composite films, with controlled wettability capabilities, deposited by a combined pulsed laser deposition (PLD)-matrix-assisted pulsed laser evaporation (MAPLE) system. Two pulsed lasers working in IR or UV were used for experiments, allowing the use of proper deposition parameters (wavelength, laser fluence, repetition rate) for each organic and inorganic component material. We have studied the time stability and wettability properties of the films and we have seen that the morphology of the surface has a low effect on the wettability of the surfaces. The obtained composite films consist in stearic acid aggregates in LDH structure, exhibiting a shift to hydrophobicity after 36 months of storage.

Challenges and Opportunities in Preclinical Research of Synthetic Cannabinoids for Pain Therapy.

Cannabis has been used in pain management since 2900 BC. In the 20th century, synthetic cannabinoids began to emerge, thus opening the way for improved efficacy. The search for new forms of synthetic cannabinoids continues and, as such, the aim of this review is to provide a comprehensive tool for the research and development of this promising class of drugs. Methods for the in vitro assessment of cytotoxic, mutagenic or developmental effects are presented, followed by the main in vivo pain models used in cannabis research and the results yielded by different types of administration (systemic versus intrathecal versus inhalation). Animal models designed for assessing side-effects and long-term uses are also discussed. In the second part of this review, pharmacokinetic and pharmacodynamic studies of synthetic cannabinoid biodistribution, together with liquid chromatography-mass spectrometric identification of synthetic cannabinoids in biological fluids from rodents to humans are presented. Last, but not least, different strategies for improving the solubility and physicochemical stability of synthetic cannabinoids and their potential impact on pain management are discussed. In conclusion, synthetic cannabinoids are one of the most promising classes of drugs in pain medicine, and preclinical research should focus on identifying new and improved alternatives for a better clinical and preclinical outcome.

A Novel Amino Lipid Series for mRNA Delivery: Improved Endosomal Escape and Sustained Pharmacology and Safety in Non-human Primates.

The success of mRNA-based therapies depends on the availability of a safe and efficient delivery vehicle. Lipid nanoparticles have been identified as a viable option. However, there are concerns whether an acceptable tolerability profile for chronic dosing can be achieved. The efficiency and tolerability of lipid nanoparticles has been attributed to the amino lipid. Therefore, we developed a new series of amino lipids that address this concern. Clear structure-activity relationships were developed that resulted in a new amino lipid that affords efficient mRNA delivery in rodent and primate models with optimal pharmacokinetics. A 1-month toxicology evaluation in rat and non-human primate demonstrated no adverse events with the new lipid nanoparticle system. Mechanistic studies demonstrate that the improved efficiency can be attributed to increased endosomal escape. This effort has resulted in the first example of the ability to safely repeat dose mRNA-containing lipid nanoparticles in non-human primate at therapeutically relevant levels.

Graphene oxide effects in early ontogenetic stages of Triticum aestivum L. seedlings.

Nanomaterials are being used increasingly in various areas such as electronic devices manufacture, medicine, mechanical devices production, and even food industry. Therefore, the evaluation of their toxicity is mandatory. Graphene oxide (GO) has been shown to have both positive as well as negative impact on different crop plants, depending on species, dose, and duration of exposure. The current study evaluated the impact of GO sheets at different concentrations (500, 1000 and 2000 mg/L) on physiological, biochemical and genetic levels to determine the possible toxic action. Wheat caryopses were treated with GO for 48 h and 7 days. The germination rate and roots elongation decreased in a dose-response manner, except the sample treated with GO at a concentration of 1000 mg/L. Mitotic index has ascendant trend; its increase may be due to the accumulation of prophases GO induced significant accumulation of the cells with aberrations, their presence suggests a clastogenic/aneugenic effect of these carbon nanomaterials. Regarding enzymatic and non-enzymatic antioxidant system defence, the activity varied depending on the dose of GO. Thus, chlorophyll a pigments content decreased significantly at high dose (2000 mg/L), while the carotenoid pigments had lower content at 500 mg/L of GO, and no statistical difference encountered in case of chlorophyll b amount. The antioxidant enzyme activity (CAT, POD, and SOD) was higher at low dose of GO, indicating the presence of oxidative stress generated as a response to the GO treatment. Also, the free radical scavenging activity of the polyphenolic compounds was enhanced upon GO exposure. The GO accumulation has been identified by transmission electron microscopy only at plumules level, near the intercellular space.