scholarly journals A Modified Method for Studying Behavioral Paradox of Antioxidants and Their Disproportionate Competitive Kinetic Effect to Scavenge the Peroxyl Radical Formation

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Nusrat Masood ◽  
Kaneez Fatima ◽  
Suaib Luqman
Keyword(s):  
Peroxyl Radical ◽  
Peroxyl Radicals ◽  
Dependent Manner ◽  
Modified Method ◽  
Radical Trapping ◽  
Cancer Initiation ◽  
Simple Kinetic Model ◽  
Dose Dependent ◽  
Peak Value

We have described a modified method for evaluating inhibitor of peroxyl radicals, a well-recognized and -documented radical involved in cancer initiation and promotion as well as diseases related to oxidative stress and ageing. We are reporting hydrophilic and lipophilic as well as natural and synthetic forms of antioxidants revealing a diversified behaviour to peroxyl radical in a dose-dependent manner (1 nM–10 μM). A simple kinetic model for the competitive oxidation of an indicator molecule (ABTS) and a various antioxidant by a radical (ROO•) is described. The influences of both the concentration of antioxidant and duration of reaction (70 min) on the inhibition of the radical cation absorption are taken into account while determining the activity. The induction time of the reaction was also proposed as a parameter enabling determination of antioxidant content by optimizing and introducing other kinetic parameters in 96-well plate assays. The test evidently improves the original PRTC (peroxyl radical trapping capacity) assay in terms of the amount of chemical used, simultaneous tracking, that is, the generation of the radical taking place continually and the kinetic reduction technique (area under curve, peak value, slope, andVmax).

A Cuticle Collagen Encoded by the lon-3 Gene May Be a Target of TGF-β Signaling in Determining Caenorhabditis elegans Body Shape

Genetics ◽  
2002 ◽  
Vol 162 (4) ◽  
pp. 1631-1639
Author(s):  
Yo Suzuki ◽  
Gail A Morris ◽  
Min Han ◽  
William B Wood
Keyword(s):  
Caenorhabditis Elegans ◽  
Body Shape ◽  
Small Body ◽  
Dependent Manner ◽  
Loss Of Function ◽  
Cellular Mechanisms ◽  
C Elegans ◽  
Gene Expression Analyses ◽  
Dose Dependent

Abstract The signaling pathway initiated by the TGF-β family member DBL-1 in Caenorhabditis elegans controls body shape in a dose-dependent manner. Loss-of-function (lf) mutations in the dbl-1 gene cause a short, small body (Sma phenotype), whereas overexpression of dbl-1 causes a long body (Lon phenotype). To understand the cellular mechanisms underlying these phenotypes, we have isolated suppressors of the Sma phenotype resulting from a dbl-1(lf) mutation. Two of these suppressors are mutations in the lon-3 gene, of which four additional alleles are known. We show that lon-3 encodes a collagen that is a component of the C. elegans cuticle. Genetic and reporter-gene expression analyses suggest that lon-3 is involved in determination of body shape and is post-transcriptionally regulated by the dbl-1 pathway. These results support the possibility that TGF-β signaling controls C. elegans body shape by regulating cuticle composition.

scholarly journals Simple determination of peroxyl radical-trapping capacity

IUBMB Life ◽  
1998 ◽  
Vol 46 (3) ◽  
pp. 519-528 ◽  
Author(s):  
Grzegorz Bartosz ◽  
Anna Janaszewska ◽  
Danuta Ertel ◽  
Maŀgorzata Bartosz
Keyword(s):  
Peroxyl Radical ◽  
Radical Trapping

Determination of mosquito bloodmeal pH in situ by ion-selective microelectrode measurement: implications for the regulation of malarial gametogenesis

Parasitology ◽  
2000 ◽  
Vol 120 (6) ◽  
pp. 547-551 ◽  
Author(s):  
O. BILLKER ◽  
A. J. MILLER ◽  
R. E. SINDEN
Keyword(s):  
Xanthurenic Acid ◽  
Mosquito Vector ◽  
Dependent Manner ◽  
Ph Increase ◽  
Ph Range ◽  
Dose Dependent

Malarial gametocytes circulate in the peripheral blood of the vertebrate host as developmentally arrested intra-erythrocytic cells, which only resume development into gametes when ingested into the bloodmeal of the female mosquito vector. The ensuing development encompasses sexual reproduction and mediates parasite transmission to the insect. In vitro the induction of gametogenesis requires a drop in temperature and either a pH increase from physiological blood pH (ca pH 7·4) to about pH 8·0, or the presence of a gametocyte-activating factor recently identified as xanthurenic acid (XA). However, it is unclear whether either the pH increase or XA act as natural triggers in the mosquito bloodmeal. We here use pH-sensitive microelectrodes to determine bloodmeal pH in intact mosquitoes. Measurements taken in the first 30 min after ingestion, when malarial gametogenesis is induced in vivo, revealed small pH increases from 7·40 (mouse blood) to 7·52 in Aedes aegypti and to 7·58 in Anophěles stephensi. However, bloodmeal pH was clearly suboptimal if compared to values required to induce gametogenesis in vitro. Xanthurenic acid is shown to extend the pH-range of exflagellation in vitro in a dose-dependent manner to values that we have observed in the bloodmeal, suggesting that in vivo malarial gametogenesis could be further regulated by both these factors.

Epinephrine sensitivity with respect to metabolic rate and other variables in women

1983 ◽  
Vol 245 (5) ◽  
pp. E431-E442 ◽  
Author(s):  
L. Sjostrom ◽  
Y. Schutz ◽  
F. Gudinchet ◽  
L. Hegnell ◽  
P. G. Pittet ◽  
...  
Keyword(s):  
Metabolic Rate ◽  
Metabolic Response ◽  
Plasma Concentrations ◽  
Fat Free Mass ◽  
Metabolic Clearance ◽  
Dependent Manner ◽  
Epinephrine Infusion ◽  
Glucose Plasma ◽  
Dose Dependent

A test for determination of epinephrine sensitivity has been worked out using six healthy young women. Variables considered were metabolic rate, heart rate, respiratory frequency, blood pressure, blood glucose, plasma insulin, glycerol, free fatty acids, and lactate. After established basal conditions, epinephrine was infused at rates of 0.01, 0.03, and 0.1 microgram X kg fat-free mass-1 X min-1. Most variables responded to epinephrine in a dose-dependent manner. Physiological threshold plasma concentrations of epinephrine ranged from 95 to 250 pg/ml for different variables. Calculated maximal responses ranged from approximately -15% to +900% of basal values and infusion rates giving half-maximal responses from approximately 15 to 190 ng X kg fat-free mass-1 X min-1. On an average, metabolic rate increased by 8, 16, and 29%, respectively, at the three infusion rates, and the maximal metabolic response was calculated to be approximately 35%. The error in determining epinephrine-induced increments in metabolic rate was 7% of the response. As calculated from nonprotein RQ, carbohydrate oxidation increased and lipid oxidation decreased rapidly during the first 10 min of epinephrine infusion. Later, fat oxidation became more important. Results on epinephrine plasma metabolic clearance rate agreed with earlier results in the literature.

scholarly journals Anti-inflammatory and antioxidant activities of Sclerochloa dura (Poaceae)

2014 ◽  
Vol 79 (7) ◽  
pp. 779-791
Author(s):  
Syed Bukhari ◽  
Astrid Feuerherm ◽  
Fayssal Boulfrad ◽  
Bojan Zlatkovic ◽  
Berit Johansen ◽  
...  
Keyword(s):  
Crude Extract ◽  
Antioxidant Activities ◽  
Oral Intake ◽  
Dependent Manner ◽  
Inhibitory Effects ◽  
Flavonoid Content ◽  
Excessive Bleeding ◽  
Release Assay ◽  
Dose Dependent

The plant Sclerochloa dura is traditionally used in South-East Serbia to treat menstrual disorders characterized by pain and excessive bleeding. According to subjects? statements, a reduction in bleeding and pain is experienced shortly after oral intake. The focus of this investigation was to determine the inhibitory effects of the plant on the arachidonic acid (AA) cascade alongwith the spectrophotometric determination of antioxidant capacity. The AA release assay was performed using the human fibroblastlike synoviocyte cell line SW982 to determine the AA release and hence phospholipase A2 (PLA2) activity. The crude extract and subsequent fractions of S. dura inhibit IL-1 induced release of AA in a time- and dose-dependent manner in SW982 cells. The IC50 for the crude extract is 1.5 mg/mL at 4 h and 24 h of stimulation. Treating the cells with 0.22, 0.11 and 0.06 mg/mL of methanolic fraction resulted in 97%, 91%, and 63% inhibition of AA-release, respectively. One milligram of the crude extract contained 34.78 ?g pyrocatechol equivalent phenolic content, 22.80 ?g quercetin equivalent flavonoid content and antioxidant activity of 70.11 ?g ?-tocopherol equivalents. Strong inhibitory effects of the S. dura extracts on AA cascade may explain the reported pain- and discomfort relieving effects.

scholarly journals Otx genes are required for tissue specification in the developing eye

Development ◽  
2001 ◽  
Vol 128 (11) ◽  
pp. 2019-2030 ◽  
Author(s):  
Juan Ramon Martinez-Morales ◽  
Massimo Signore ◽  
Dario Acampora ◽  
Antonio Simeone ◽  
Paola Bovolenta
Keyword(s):  
Apoptotic Cell ◽  
Pigment Epithelium ◽  
Neural Retina ◽  
Dependent Manner ◽  
Gene Products ◽  
Optic Stalk ◽  
Mutual Regulation ◽  
Vertebrate Eye ◽  
Dose Dependent

Patterning of the vertebrate eye appears to be controlled by the mutual regulation and the progressive restriction of the expression domains of a number of genes initially co-expressed within the eye anlage. Previous data suggest that both Otx1 and Otx2 might contribute to the establishment of the different eye territories. Here, we have analysed the ocular phenotype of mice carrying different functional copies of Otx1 and Otx2 and we show that these genes are required in a dose-dependent manner for the normal development of the eye. Thus, all Otx1−/−; Otx2+/− and 30% of Otx1+/−; Otx2+/− genotypes presented consistent and profound ocular malformation, including lens, pigment epithelium, neural retina and optic stalk defects. During embryonic development, optic vesicle infolding was severely altered and the expression of pigment epithelium-specific genes, such as Mitf or tyrosinase, was lost. Lack of pigment epithelium specification was associated with an expansion of the prospective neural retina and optic stalk territories, as determined by the expression of Pax6, Six3 and Pax2. Later in development the presumptive pigment epithelium region acquired features of mature neural retina, including the generation of Islet1-positive neurones. Furthermore, in Otx1−/−; Otx2+/− mice neural retina cell proliferation, cell differentiation and apoptotic cell death were also severely affected. Based on these findings we propose a model in which Otx gene products are required for the determination and differentiation of the pigment epithelium, co-operating with other eye patterning genes in the determination of the specialised tissues that will constitute the mature vertebrate eye.

Determination of changes in Arthrospira platensis antioxidant activity and growth parameters due to oxidative stress arising from Lambda cyhalothrin

2020 ◽  
Vol 56 ◽  
pp. 27
Author(s):  
Hatice Tunca
Keyword(s):  
Oxidative Stress ◽  
Growth Parameters ◽  
Arthrospira Platensis ◽  
Dependent Manner ◽  
Lake Ecosystems ◽  
Pesticide Pollution ◽  
Lambda Cyhalothrin ◽  
Dose Dependent ◽  
And Oxidative Stress

Toxic stress caused by pesticides changes the function and structure of the aquatic ecosystem via impressing to species composition. Therefore it is necessary to determine the reaction of cyanobacteria to pesticides for comprehend the effects of these substances on the aquatic ecosystems. This study aims to determine the toxicity and oxidative stress that Lambda cyhalothrin may cause in cyanobacteria, one of the primary producers in lake ecosystems. For these reasons, the changes in chlorophyll-a content, OD560 absorbance, the antioxidant enzyme acitvities such as superoxidedismutase (SOD), ascorbate peroxidase (APX), and glutathione reducatse (GR) were assessed to carry out the effect of Lambda cyhalothrin concentrations (between 6.25 and 100 μg ml−1) on Arthrospira platensis. EC50 value is calculated as 11.94 μg m l−1 Lambda cyhalothrin concentrations. SOD and APX activities was statistically different from the control at 100 μg m l−1 Lambda cyhalothrin application compared to control in A. platensis-M2 cells. On the other hand, GR activity did not effect significantly. According to our results, we may conclude that Lambda cyhalothrin concentrations used in this study inhibited the growth of A. platensis cells in a time and dose-dependent manner, as indicated by lowered chlorophyll-a content and OD560 values and Lambda cyhalothrin caused oxidative stress in A. platensis cells. As a result, the restriction of Lambda cyhalothrin using at the certain concentrations may be a step to prevent pesticide pollution in the environment.

Detection of Sodium Channel Toxins: Directed Cytotoxicity Assays of Purified Ciguatoxins, Brevetoxins, Saxitoxins, and Seafood Extracts

1995 ◽  
Vol 78 (2) ◽  
pp. 521-527 ◽  
Author(s):  
Ron L Manger ◽  
Linda S Leja ◽  
Sue Y Lee ◽  
Jem M Hungerford ◽  
Yoshttsugi Hokama ◽  
...  
Keyword(s):  
Sodium Channel ◽  
Neuroblastoma Cells ◽  
Dependent Manner ◽  
Animal Testing ◽  
Toxic Activity ◽  
Channel Blocking ◽  
Point Determination ◽  
Dose Dependent ◽  
Mitochondrial Dehydrogenase Activity

Abstract Neuroblastoma cells in culture were used to detect sodium channel-specific marine toxins based on an end-point determination of mitochondrial dehydrogenase activity. The assay responds in a dose-dependent manner to ciguatoxins, brevetoxins, and saxitoxins, and delineates the toxic activity as either sodium channel enhancing or sodium channel blocking. The assay responds rapidly to sodium channel activating toxins, allowing dose dependent detection in 4 to 6 h. Brevetoxins can be detected at 250 pg, and purified ciguatoxins are detected in the low picogram and subpicogram levels. The results obtained from cell bioassay of ciguatoxic finfish extracts correlates with those obtained from mouse bioassays. Sodium channel blocking toxins can also be detected with an approximate sensitivity of 20 pg in 24 to 48 h. This cell-based technique is simple, sensitive, demonstrates potential as an alternative to animal testing for sodium channel activating and blocking toxins, and can be automated.

scholarly journals Liposomal form of lipoic acid: preparation and determination of antiplatelet and antioxidant activity

2016 ◽  
Vol 62 (5) ◽  
pp. 577-583 ◽  
Author(s):  
V.A. Shchelkonogov ◽  
G.M. Sorokoumova ◽  
O.A. Baranova ◽  
A.V. Chekanov ◽  
A.V. Klochkova ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Arachidonic Acid ◽  
Platelet Aggregation ◽  
Lipoic Acid ◽  
Platelet Rich Plasma ◽  
Antioxidant Properties ◽  
Dependent Manner ◽  
Liposomal Form ◽  
Dose Dependent

Optimal conditions for obtaining phosphatidylholine (PC) liposomes with lipoic acid (LA) are chosen that lead to the formation of nanoparticles with a size of 175¸284 nm with efficiency (extent) of inclusion of LA in liposomes equal 85% and characterized by a slow release of substance from the nanoparticles. The effect of “empty” liposomes and liposomal form of LA on platelet aggregation induced by arachidonic acid (AA) is established. It is found that liposomes with LА inhibit platelet aggregation, caused by AА, to 80%. In addition, it is shown that “empty” liposomes slightly (to 30%) suppress platelet aggregation, caused by AА. The amount of TBA-sensitive products in samples of platelet-rich plasma (PRP) incubated with liposomal LA is determined. It is shown that LA in the composition of liposomes retains its antioxidant properties, and the amount of products of lipid peroxidation in platelet-rich plasma decreases in a dose-dependent manner when arachidonic acid is used as an inductor of platelet aggregation. It is assumed that the antiplatelet action of the liposomal form of LА is induced by inhibition of the initiation of lipid peroxidation products caused by exogenous inducer AА. It is supposed that, after additional research, the liposomal form of LA can be considered as a new drug in complex treatment of cerebral ischemia.

Research on Biological Materials with Oxazinone Derivatives Induce Apoptosis in HT-29 Cells

2014 ◽  
Vol 908 ◽  
pp. 220-223
Author(s):  
Yan Ling Wu ◽  
Li Wen Shen ◽  
Yan Ping Ding ◽  
Chuan He Wei ◽  
Yoshimasa Tanaka ◽  
...  
Keyword(s):  
Growth Inhibition ◽  
Real Time ◽  
Biological Materials ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Cytotoxic Effects ◽  
Induction Of Apoptosis ◽  
Dose Dependent ◽  
Ht 29

Objective: To monitor the induction of apoptosis in HT-29 cells by three compounds of oxazinone derivatives (A-C) with similar structures and research the mechanism of those oxazinone derivatives in induction of apoptosis in HT-29 cells. Methods: HT-29 cells were used for the determination of cytotoxicity elicited by oxazinone compounds. Cytotoxic effects of these compounds in HT-29 cells are monitored by a Real-Time Cell Analyser system. Results: All the oxazinone derivatives exhibited growth inhibition in HT-29 cells in a concentration-dependent manner. Conclusion: All the three compounds of oxazinone derivatives (A-C) could exhibit growth inhibition in HT-29 cells in a dose-dependent manner.

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