Search results for "nitrogen."
showing 10 items of 1167 documents
European catfish (Silurus glanis) as a freshwater apex predator drives ecosystem via its diet adaptability
2017
AbstractApex predators play a key role in ecosystem stability across environments but their numbers in general are decreasing. By contrast, European catfish (Silurus glanis), the European freshwater apex predator, is on the increase. However, studies concerning apex predators in freshwaters are scarce in comparison to those in terrestrial and marine ecosystems. The present study combines stomach content and stable isotope analyses with diet preferences of catfish to reveal its impact on the ecosystem since stocking. Catfish niche width is extremely wide in comparison to the typical model predator, Northern pike (Esox lucius). Catfish and pike have different individual dietary specialization…
Nitric oxide contributes to cadmium toxicity in Arabidopsis by promoting cadmium accumulation in roots and by up-regulating genes related to iron upt…
2009
Abstract Nitric oxide (NO) functions as a cell-signaling molecule in plants. In particular, a role for NO in the regulation of iron homeostasis and in the plant response to toxic metals has been proposed. Here, we investigated the synthesis and the role of NO in plants exposed to cadmium (Cd2+), a nonessential and toxic metal. We demonstrate that Cd2+ induces NO synthesis in roots and leaves of Arabidopsis (Arabidopsis thaliana) seedlings. This production, which is sensitive to NO synthase inhibitors, does not involve nitrate reductase and AtNOA1 but requires IRT1, encoding a major plasma membrane transporter for iron but also Cd2+. By analyzing the incidence of NO scavenging or inhibition …
An overview on the recent developments of 1,2,4-triazine derivatives as anticancer compounds
2017
The synthesis, the antitumor activity, the SAR and, whenever described, the possible mode of action of 1,2,4-triazine derivatives, their N-oxides, N,. N'-dioxides as well as the benzo- and hetero-fused systems are reported. Herein are treated derivatives disclosed to literature from the beginning of this century up to 2016. Among the three possible triazine isomers, 1,2,4-triazines are the most studied ones and many derivatives having remarkable antitumor activity have been reported in the literature and also patented reaching advanced phases of clinical trials.
Mechanisms of action of metformin in type 2 diabetes: Effects on mitochondria and leukocyte-endothelium interactions.
2020
Type 2 diabetes (T2D) is a very prevalent, multisystemic, chronic metabolic disorder closely related to atherosclerosis and cardiovascular diseases. It is characterised by mitochondrial dysfunction and the presence of oxidative stress. Metformin is one of the safest and most effective anti-hyperglycaemic agents currently employed as first-line oral therapy for T2D. It has demonstrated additional beneficial effects, unrelated to its hypoglycaemic action, on weight loss and several diseases, such as cancer, cardiovascular disorders and metabolic diseases, including thyroid diseases. Despite the vast clinical experience gained over several decades of use, the mechanism of action of metformin i…
Indicaxanthin from Opuntia ficus indica (L. Mill) Inhibits Oxidized LDL-Mediated Human Endothelial Cell Dysfunction through Inhibition of NF-κB Activ…
2019
Oxidized low-density lipoproteins (oxLDL) play a pivotal role in the etiopathogenesis of atherosclerosis through the activation of inflammatory signaling events eventually leading to endothelial dysfunction and senescence. In the present work, we investigated the effects of indicaxanthin, a bioavailable, redox-modulating phytochemical from Opuntia ficus indica fruits, with anti-inflammatory activity, against oxLDL-induced endothelial dysfunction. Human umbilical vein cord cells (HUVEC) were stimulated with human oxLDL, and the effects of indicaxanthin were evaluated in a range between 5 and 20 μM, consistent with its plasma level after a fruit meal (7 μM). Pretreatment with indicaxanthin si…
Synthesis and antitumor activities of 1,2,3-triazines and their benzo- and heterofused derivatives
2017
1,2,3-Triazines are a class of biologically active compounds that exhibit a broad spectrum of activities, including antibacterial, antifungal, antiviral, antiproliferative, analgesic and anti-inflammatory properties. This review, which covers the literature from the end of last century to 2016, treats, through a comprehensive, systematic approach, the 1,2,3-triazine and related benzo- and hetero-fused derivatives possessing antitumor activity. Their efficacy, combined with a simple synthesis confers to these molecules a great potential as scaffold for the development of antitumor compounds.
The Antioxidant Therapy: New Insights in the Treatment of Hypertension
2018
Reactive oxygen species (ROS) and reactive nitrogen species (RNS) play a key role in the regulation of the physiological and pathological signaling within the vasculature. In physiological conditions, a delicate balance between oxidants and antioxidants protects cells from the detrimental effects of ROS/RNS. Indeed, the imbalance between ROS/RNS production and antioxidant defense mechanisms leads to oxidative and nitrosative stress within the cell. These processes promote the vascular damage observed in chronic conditions, such as hypertension. The strong implication of ROS/RNS in the etiology of hypertension suggest that antioxidants could be effective in the treatment of this pathology. I…
Peripheral artery disease, redox signaling, oxidative stress – Basic and clinical aspects
2017
Reactive oxygen and nitrogen species (ROS and RNS, e.g. H2O2, nitric oxide) confer redox regulation of essential cellular signaling pathways such as cell differentiation, proliferation, migration and apoptosis. At higher concentrations, ROS and RNS lead to oxidative stress and oxidative damage of biomolecules (e.g. via formation of peroxynitrite, fenton chemistry). Peripheral artery disease (PAD) is characterized by severe ischemic conditions in the periphery leading to intermittent claudication and critical limb ischemia (end stage). It is well known that redox biology and oxidative stress play an important role in this setting. We here discuss the major pathways of oxidative stress and re…
Regulation of vascular function and inflammation via cross talk of reactive oxygen and nitrogen species from mitochondria or nadph oxidase—implicatio…
2020
Oxidative stress plays a key role for the development of cardiovascular, metabolic, and neurodegenerative disease. This concept has been proven by using the approach of genetic deletion of reactive oxygen and nitrogen species (RONS) producing, pro-oxidant enzymes as well as by the overexpression of RONS detoxifying, antioxidant enzymes leading to an amelioration of the severity of diseases. Vice versa, the development and progression of cardiovascular diseases is aggravated by overexpression of RONS producing enzymes as well as deletion of RONS detoxifying enzymes. We have previously identified cross talk mechanisms between different sources of RONS, which can amplify the oxidative stress-m…
Contribution of aerobic anoxygenic phototrophic bacteria to total organic carbon pool in aquatic system of subtropical karst catchments, Southwest Ch…
2017
Aerobic anoxygenic phototrophic bacteria may play a particular role in carbon cycling of aquatic systems. However, little is known about the interaction between aerobic anoxygenic phototrophic bacteria and hydrochemistry in groundwater-surface water exchange systems of subtropical karst catchments. We carried out a detailed study on the abundance of aerobic anoxygenic phototrophic bacteria and bacterioplankton, hydrochemistry and taxonomy of bacterioplankton in the Maocun watershed, Southwest China, an area with karst geological background. Our results revealed that bacteria are the important contributors to total organic carbon source/sequestration in the groundwater-surface water of this …