Mitochondria activity

Inhibition and stimulation of LOX activity occurs as a rule by a free radical mechanism. Riendeau et al. [8] showed that hydroperoxide activation of 5-LOX is product-specific and can be stimulated by 5-HPETE and hydrogen peroxide. NADPH, FAD, Fe2+ ions, and Fe3+(EDTA) complex markedly increased the formation of oxidized products while NADH and 5-HETE were inhibitory. Jones et al. [9] also demonstrated that another hydroperoxide 13(5)-hydroperoxy-9,ll( , Z)-octadecadienoic acid (13-HPOD) (formed by the oxidation of linoleic acid by soybean LOX) activated the inactive ferrous form of the enzyme. These authors suggested that 13-HPOD attached to LOX and affected its activation through the formation of a protein radical. Werz et al. [10] showed that reactive oxygen species produced by xanthine oxidase, granulocytes, or mitochondria activated 5-LOX in the Epstein Barr virus-transformed B-lymphocytes. 

A further option to investigate the phototoxic potential of substances is the use of reconstructed human skin models. The evaluation of the cell viability is based on the MTT-assay that is sensitive for the mitochondria activity in cells. Currently, these in vivo substitutes are still under validation and are not approved as full standard test methods for the investigation of the phototoxicity potency of a test chemical. However, several existing models are in use for prevalidation studies and are described elsewhere in more detail [92],... 

Ravanel, P., Taillander, G., Tissut, M. and Benoit-Guyod, J.L. (1985). Effects of Chlorophenols on Isolated Plant Mitochondria Activities A QSAR Study. Ecotox.Environ.Safe., 9,300-320. 

Hallstrdm, T.C. and Moye-Rowley, W.S. (2000) Multiple signals from dysfunctional mitochondria activate the pleiotropic drug resistance pathway in Saccharomyces cerevisiae. The Journal of Biological Chemistry, 275. 37347-37356. 

Medium-chain acyl-CoA synthetases exist in mitochondria of various mammalian tissues. The enzyme present in heart mitochondria acts on fatty acids with three to seven carbon atoms, but is most active with butyrate. In contrast, a 62-kDa enzyme of liver mitochondria activates fatty acids with 4-14 carbon atoms with octanoate being the best substrate. This enzyme also activates aromatic carboxylic acids such as benzoic acid and... 

II in isolated muscle mitochondria revealed several difficulties. Whereas CPT I is normally active in isolated intact mitochondria, activity of CPT II is latent under these conditions. Under some conditions, such as freeze-thawing of mitochondria, the releasing of the CPT II activity is accompanied by a masking of CPT I activity. Therefore, the apparent total CPT activity decreases after such procedures.Similar studies with liver mitochondria, however, revealed clearly increased activities of total CPT after membrane disruptive procedimes. ... 

Resveratrol (grape, red wine) HL-60 human leukemia cell line, SHEP neuroblastoma cells Release of cytochrome c from mitochondria, activation of caspases, induction of p53-dependent transcriptional activation sensitizes TRAIL-induced apoptosis decreases in survivin, increases in Smac/DIABLO [155,156]... 

Besides multiple staining protocols, a mitochondria potential assay was applied to further assess the toxicity, which was able to rapidly measure the effect of compound on mitochondria potential. After cells were treated with compounds for 60 min, the mitochondria-active dye JC-10 was added for 15-30 min incubation with reagents. In addition, the assay was able to test the effects on inducing autophagy and phospholipidosis after treating the cell with compounds for 24 and 48 h, respectively. The method is compatible for screening of hundreds of compounds within 72 h. 

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