Nanotechnology, new fascinating field of science, is bringing many application's options. However, it is necessary to understand their potential environmental risk and toxicity. Zinc selenide quantum dots (ZnSe QDs) are getting valuable due to wide industrial usage, mainly as cadmium free diodes or stabilizing ligand. Thanks to unique properties, they could also open the possibilities of application in the agriculture. Their effects on living organisms, including plants, are still unknown. Therefore, the attention of this work was given to antioxidant response of Arabidopsis thaliana to 100 and 250 μM ZnSe QDs foliar feeding. ZnSe QDs treatment had no statistically significant differences in morphology but led to increased antioxidant response in the leaves at the level of gene expression and production secondary antioxidant metabolites. Concurrently, analysis of growth properties of Agrobacterium tumefaciens was done. 250 μM ZnSe solution inhibited the Agrobacterium tumefaciens viability by 60%. This is the first mention about effect ZnSe QDs on the plants. Although QDs induced oxidative stress, the apply treatment dose of ZnSe QDs did not have significant toxic effect on the plants and even no morphological changes were observed. However, the same amount of ZnSe QD induced an inhibitory effect on Agrobacterium tumefaciens.

• MeSH
• Agrobacterium tumefaciens drug effects   growth & development   MeSH
• Antioxidants metabolism   MeSH
• Arabidopsis genetics   growth & development   metabolism   MeSH
• Gene Expression * MeSH
• Quantum Dots toxicity   MeSH
• Metabolomics * MeSH
• Selenium Compounds administration & dosage   toxicity   MeSH
• Zinc Compounds administration & dosage   toxicity   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Alzheimer's disease (AD) is a neurodegenerative disorder presenting one of the biggest healthcare challenges in developed countries. No effective treatment exists. In recent years the main focus of AD research has been on the amyloid hypothesis, which postulates that extracellular precipitates of beta amyloid (Aβ) derived from amyloid precursor protein (APP) are responsible for the cognitive impairment seen in AD. Treatment strategies have been to reduce Aβ production through inhibition of enzymes responsible for its formation, or to promote resolution of existing cerebral Aβ plaques. However, these approaches have failed to demonstrate significant cognitive improvements. Intracellular rather than extracellular events may be fundamental in AD pathogenesis. Selenate is a potent inhibitor of tau hyperphosphorylation, a critical step in the formation of neurofibrillary tangles. Some selenium (Se) compounds e.g. selenoprotein P also appear to protect APP against excessive copper and iron deposition. Selenoproteins show anti-inflammatory properties, and protect microtubules in the neuronal cytoskeleton. Optimal function of these selenoenzymes requires higher Se intake than what is common in Europe and also higher intake than traditionally recommended. Supplementary treatment with N-acetylcysteine increases levels of the antioxidative cofactor glutathione and can mediate adjuvant protection. The present review discusses the role of Se in AD treatment and suggests strategies for AD prevention by optimizing selenium intake, in accordance with the metal dysregulation hypothesis. This includes in particular secondary prevention by selenium supplementation to elderly with mild cognitive impairment.

• MeSH
• Alzheimer Disease diet therapy   drug therapy   metabolism   MeSH
• Humans MeSH
• Oxidative Stress drug effects   MeSH
• Dietary Supplements * MeSH
• Selenium Compounds administration & dosage   metabolism   pharmacology   therapeutic use   MeSH
• Inflammation drug therapy   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Review MeSH

The function of selenium in an organism is mediated mostly by selenoproteins including glutathione peroxidase. Glutathione peroxidase is a potent anti-oxidative enzyme, scavenging a variety of peroxides. The green alga Scenedesmus quadricauda was used to investigate the relationship between the toxicity of selenium and the glutathione peroxidase activity. Selenium resistant strains SeIV and SeVI were synchronized and grown in high concentrations of Se (selenite or selenate). As a measure of selenium toxicity the EC(50) values were determined. During growth of the untreated wild type, glutathione peroxidase activity increased slightly and then declined gradually until the end of the cell cycle. A similar pattern was observed in untreated resistant strains and when resistant strains were grown in the presence of selenium in the oxidation state to which they were resistant. In the wild type cultivated with 50 mg Se L(-1) (selenite or selenate), activity increased to a high level and slowly declined until the end of the cell cycle. Similarly, activity increased in strains SeIV and SeVI when grown in the presence of selenium in the oxidation state to which they were not resistant. We followed the effect of selenium on the ultrastructure of S. quadricauda. After exposure to selenite, the chloroplast membranes of wild type were reorganized into thick bundles of thylakoids and the stroma became granulose. When selenate was added, the chloroplast of wild type had a fingerprint-like appearance, the stroma became less dense and starch production increased. In selenium resistant strains, when treated with the selenium form to which they were resistant, the chloroplast was affected, but not to such an extent as in the wild type. The activity of glutathione peroxidase in Scenedesmus was affected by selenium in an oxidation state-dependent manner. The most apparent effects of selenium on the ultrastructure involved impairment of the chloroplast and the overproduction of starch.

• MeSH
• Cell Cycle drug effects   physiology   MeSH
• Chloroplasts drug effects   metabolism   ultrastructure   MeSH
• Stress, Physiological MeSH
• Plants, Genetically Modified MeSH
• Glutathione Peroxidase metabolism   MeSH
• Culture Techniques MeSH
• Scenedesmus cytology   drug effects   enzymology   physiology   MeSH
• Selenium administration & dosage   analysis   toxicity   MeSH
• Sodium Selenite administration & dosage   toxicity   MeSH
• Selenium Compounds administration & dosage   toxicity   MeSH
• Toxicity Tests MeSH
• Dose-Response Relationship, Drug MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

• MeSH
• Organoselenium Compounds toxicity   MeSH
• Selenium Compounds administration & dosage   MeSH