scholarly journals Molecules released by helminth parasites involved in host colonization.

2006 ◽  
Vol 53 (1) ◽  
pp. 33-64 ◽  
Author(s):  
Jolanta M Dzik
Keyword(s):  
Reactive Oxygen Species ◽  
Antioxidant Enzymes ◽  
Trichinella Spiralis ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Helminth Parasites ◽  
Way Of Life ◽  
Metabolizing Enzymes ◽  
Immune Attack ◽  
Living Organisms

Parasites are designed by evolution to invade the host and survive in its organism until they are ready to reproduce. Parasites release a variety of molecules that help them to penetrate the defensive barriers and avoid the immune attack of the host. In this respect, particularly interesting are enzymes and their inhibitors secreted by the parasites. Serine-, aspartic-, cysteine-, and metalloproteinases are involved in tissue invasion and extracellular protein digestion. Helminths secrete inhibitors of these enzymes (serpins, aspins, and cystatins) to inhibit proteinases, both of the host and their own. Proteinases and their inhibitors, as well as helminth homologues of cytokines and molecules containing phosphorylcholine, influence the immune response of the host biasing it towards the anti-inflammatory Th2 type. Nucleotide-metabolizing enzymes and cholinesterase are secreted by worms to reduce inflammation and expel the parasites from the gastrointestinal tract. An intracellular metazoan parasite, Trichinella spiralis, secretes, among others, protein kinases and phosphatases, endonucleases, and DNA-binding proteins, which are all thought to interfere with the host cellular signals for muscle cell differentiation. Secretion of antioxidant enzymes is believed to protect the parasite from reactive oxygen species which arise from the infection-stimulated host phagocytes. Aside from superoxide dismutase, catalase (rarely found in helminths), and glutathione peroxidase (selenium-independent, thus having a poor activity with H(2)O(2)), peroxiredoxins are probably the major H(2)O(2)-detoxifying enzymes in helminths. Secretion of antioxidant enzymes is stage-specific and there are examples of regulation of their expression by the concentration of reactive oxygen species surrounding the parasite. The majority of parasite-secreted molecules are commonly found in free-living organisms, thus parasites have only adapted them to use in their way of life.

scholarly journals Upconversion-based nanosystems for fluorescence sensing of pH and H2O2

2021 ◽  
Author(s):  
Chunning Sun ◽  
Michael Gradzielski
Keyword(s):  
Reactive Oxygen Species ◽  
Hydrogen Peroxide ◽  
Excitation Energy ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Fluorescence Sensing ◽  
Living Organisms

Hydrogen peroxide (H2O2), a key reactive oxygen species, plays an important role in living organisms, industrial and environmental fields. Here, a non-contact upconversion nanosystem based on the excitation energy attenuation...

scholarly journals Antioxidant, α-Glucosidases and α-Amylase Inhibitory Activities of Persicaria odorata

2021 ◽  
Vol 20 (3) ◽  
Author(s):  
Kanya Thongra-ar ◽  
Piyanuch Rojsanga ◽  
Savita Chewchinda ◽  
Supachoke Mangmool ◽  
Pongtip Sithisarn
Keyword(s):  
Reactive Oxygen Species ◽  
Antioxidant Enzymes ◽  
Reactive Oxygen ◽  
Total Flavonoid ◽  
Total Phenolic ◽  
Oxygen Species ◽  
Hek 293 ◽  
Hek 293 Cells ◽  
293 Cells ◽  
Ic50 Values

The objects of this study were to determine the effects to reactive oxygen species and antioxidant enzymes levels in HEK-293 cells and inhibition of α-glucosidases and α-amylase enzymes of extracts from Persicaria odorata or phak phaeo. The ethanol extracts from the leaves and the stems of phak phaeo were investigated for their 2,2-diphenyl-1-picryhydrazyl (DPPH) scavenging activities (IC50 were 7.74 ± 0.47 and 7.91 ± 0.43 µg/mL, respectively). Cellular antioxidant effects in human embryonic kidney-293 (HEK-293) cells with these extracts (0.1 mg/mL) also increased the mRNA expressions of manganese superoxide dismutase (Mn-SOD), glutathione peroxidase 1 (GPx-1), catalase and glutathione reductase (GRe). The leaf extract showed the higher efficacies in the induction of the mRNA expressions of Mn-SOD, GPx-1 and GRe while the stem extract exhibited a stronger effect to the induction of catalase. Phak phaeo in vitro inhibitory effects to α-glucosidase enzyme (IC50 values of 9.82 ± 1.64 and 13.99 ± 1.45 µg/mL, respectively and also strong inhibition to α-amylase with IC50 values of 90.66 ± 8.75 and 19.96 ± 5.37 µg/mL, respectively). Lineweaver-Burk plot demonstrated that phak phaeo extracts inhibited α-glucosidase and α- amylase in non-competitive manners. Total phenolic and total flavonoid contents were determined by Folin-Ciocalteu and aluminium chloride methods (the leaf and stem extracts were 22.89 ± 9.16 and 22.27 ± 8.77 g gallic acid equivalent in 100 g extract (g% GAE) and 7.20 ± 3.61 and 4.06 ± 1.73 g quercetin equivalent in 100 g extract (g% QE), respectively). Keywords: Antioxidant enzymes, DPPH, HEK-293, MTT assay, Persicaria odorata, Reactive oxygen species, Total phenolic, Total flavonoid, α-glucosidases, α-amylase

Exploring the Potentials of Antioxidants in Retarding Ageing

2017 ◽  
pp. 166-195 ◽  
Author(s):  
Minu Kesheri ◽  
Swarna Kanchan ◽  
Rajeshwar P. Sinha
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Growth And Development ◽  
Aging Process ◽  
Reactive Oxygen ◽  
Normal Growth ◽  
Antioxidant Defenses ◽  
Oxygen Species ◽  
Biotic Stresses ◽  
Living Organisms

In retrospect to the rise in the occurrence of ageing related disorders and the everlasting desire to overcome ageing, exploring the causes, mechanisms and therapies to curb ageing becomes relevant. Reactive Oxygen Species (ROS) are commonly generated during normal growth and development. However abiotic and biotic stresses enhance the level of ROS which in turn pose the threat of oxidative stress. Ability to perceive ROS and to speedily commence antioxidant defenses is crucial for the survival as well as longevity of living cells. Therefore living organisms are bestowed with antioxidants to combat the damages caused by oxidative stress. This chapter aims to elucidate an overview of the process of ageing, generation and enhancement of reactive oxygen species, damages incurred by oxidative stress, its amelioration strategies, therapeutic and biotechnological potentials of antioxidants and various sources of bioactive compounds significant in retardation of aging process.

scholarly journals Influence of Acetylcholinesterase Inhibitors Used in Alzheimer’s Disease Treatment on the Activity of Antioxidant Enzymes and the Concentration of Glutathione in THP-1 Macrophages under Fluoride-Induced Oxidative Stress

2018 ◽  
Vol 16 (1) ◽  
pp. 10 ◽  
Author(s):  
Marta Goschorska ◽  
Izabela Gutowska ◽  
Irena Baranowska-Bosiacka ◽  
Katarzyna Piotrowska ◽  
Emilia Metryka ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Alzheimer’S Disease ◽  
Reactive Oxygen Species ◽  
Alzheimer's Disease ◽  
Antioxidant Enzymes ◽  
Antioxidant Properties ◽  
Reactive Oxygen ◽  
Acetylcholinesterase Inhibitors ◽  
Oxygen Species ◽  
Ache Inhibitors

It has been reported that donepezil and rivastigmine, the acetylcholinesterase (AchE) inhibitors commonly used in the treatment of Alzheimer’s disease (AD), do not only inhibit AChE but also have antioxidant properties. As oxidative stress is involved in AD pathogenesis, in our study we attempted to examine the influence of donepezil and rivastigmine on the activity of antioxidant enzymes and glutathione concentration in macrophages—an important source of reactive oxygen species and crucial for oxidative stress progression. The macrophages were exposed to sodium fluoride induced oxidative stress. The antioxidant enzymes activity and concentration of glutathione were measured spectrophotometrically. The generation of reactive oxygen species was visualized by confocal microscopy. The results of our study showed that donepezil and rivastigmine had a stimulating effect on catalase activity. However, when exposed to fluoride-induced oxidative stress, the drugs reduced the activity of some antioxidant enzymes (Cat, SOD, GR). These observations suggest that the fluoride-induced oxidative stress may suppress the antioxidant action of AChE inhibitors. Our results may have significance in the clinical practice of treatment of AD and other dementia diseases.

Antioxidant enzymes and reactive oxygen species level of the Achromobacter xylosoxidans bacteria during hydrocarbons biotransformation

2018 ◽  
Vol 200 (7) ◽  
pp. 1057-1065 ◽  
Author(s):  
I. S. Sazykin ◽  
M. A. Sazykina ◽  
L. E. Khmelevtsova ◽  
E. Yu. Seliverstova ◽  
K. Sh. Karchava ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Antioxidant Enzymes ◽  
Reactive Oxygen ◽  
Species Level ◽  
Reactive Oxygen Species Level ◽  
Achromobacter Xylosoxidans ◽  
Oxygen Species
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