Elucidating the origin of the surface functionalization - dependent bacterial toxicity of graphene nanomaterials: Oxidative damage, physical disruption, and cell autolysis

2020 ◽  
Vol 747 ◽  
pp. 141546 ◽  
Author(s):  
Changjian Xie ◽  
Peng Zhang ◽  
Zhiling Guo ◽  
Xiaowei Li ◽  
Qiuxiang Pang ◽  
...  
Author(s):  
O. T. Minick ◽  
E. Orfei ◽  
F. Volini ◽  
G. Kent

Hemolytic anemias were produced in rats by administering phenylhydrazine or anti-erythrocytic (rooster) serum, the latter having agglutinin and hemolysin titers exceeding 1:1000.Following administration of phenylhydrazine, the erythrocytes undergo oxidative damage and are removed from the circulation by the cells of the reticulo-endothelial system, predominantly by the spleen. With increasing dosage or if animals are splenectomized, the Kupffer cells become an important site of sequestration and are greatly hypertrophied. Whole red cells are the most common type engulfed; they are broken down in digestive vacuoles, as shown by the presence of acid phosphatase activity (Fig. 1). Heinz body material and membranes persist longer than native hemoglobin. With larger doses of phenylhydrazine, erythrocytes undergo intravascular fragmentation, and the particles phagocytized are now mainly red cell fragments of varying sizes (Fig. 2).


Author(s):  
Randy Moore

Previous work has indicated that the graft incompatihility between Sedrmi telephoides and Solanum pennellil involves cell necrosis that results In a thick layer of collapsed cells at the graft Interface. This necrotic layer insulates the stock from the scion, which results in abscission of the Sedum scion after 4-6 weeks due to desiccation and starvation. Thus, cell autolysis (which is restricted to Sedum) characterizes the Incompatibility response in this system (1). In order to elucidate the events that lead to cell autolysis, and thus better understand the cellular site and mode of action of cellular incompatibility, the appearance and fate of the hydrolytlc enzyme acid phosphatase (AP) was followed in both the compatible Sedum autograft and the incompatible Sedum/Solanum heterograft. Acid phosphatase was localized by a modified Gomori-type reaction; positive (i.e., including NaF inhibitor) and negative (lacking substrate) controls showed no enzymatic precipitate. Following an initial association with the endoplasmic reticulum (ER) and dictyosomes at 6-10 hours after grafting, AP activity in the compatible Sedum autograft is associated primarily with the plasmalemma (Fig. 1). By 18-24 hours after grafting, the AP activity is restricted to the tono-plast and vacuole (Fig. 2). This strict compartmentation and absence of enzyme from the cytosol is maintained throughout the development of the compatible graft. While AP activity in the incompatible Sedum/Solanum heterograft is Initially similar to the compatible Sedum autograft (i.e., initially found on the ER and dictyosomes), there is a marked difference in enzyme localization in the two graft partners as the incompatibility response develops. As in the compatible autograft, Solanum cells at the graft interface show an Increase in AP activity that Is restricted to the vacuole and tonoplast, with little or no enzyme activity in the cytosol (Fig. 3). In comparable Sedum cells, however, there is a dramatic Increase In AP activity in the cytosol (Fig. h); this cytosollc AP activity is associated with thin fibril-like structures (Fig. 5) measuring approximately 60 A in diameter. This high cytoplasmic AP activity In Sedum cells results in cell autolysis, death, and eventual cell collapse to form the characteristic necrotic layer separating the two graft partners.


2010 ◽  
Vol 34 (8) ◽  
pp. S27-S27
Author(s):  
Xueling Dai ◽  
Ping Chang ◽  
Ke Xu ◽  
Changjun Lin ◽  
Hanchang Huang ◽  
...  

2002 ◽  
Vol 7 (5) ◽  
pp. 295-313 ◽  
Author(s):  
Patricia A. McChesney ◽  
Lynne W. Elmore ◽  
Shawn E. Holt
Keyword(s):  

Author(s):  
Paulina Iwan ◽  
Jan Stepniak ◽  
Malgorzata Karbownik-Lewinska

Abstract. Iodine is essential for thyroid hormone synthesis. Under normal iodine supply, calculated physiological iodine concentration in the thyroid is approx. 9 mM. Either potassium iodide (KI) or potassium iodate (KIO3) are used in iodine prophylaxis. KI is confirmed as absolutely safe. KIO3 possesses chemical properties suggesting its potential toxicity. Melatonin (N-acetyl-5-methoxytryptamine) is an effective antioxidant and free radical scavenger. Study aims: to evaluate potential protective effects of melatonin against oxidative damage to membrane lipids (lipid peroxidation, LPO) induced by KI or KIO3 in porcine thyroid. Homogenates of twenty four (24) thyroids were incubated in presence of either KI or KIO3 without/with melatonin (5 mM). As melatonin was not effective against KI-induced LPO, in the next step only KIO3 was used. Homogenates were incubated in presence of KIO3 (200; 100; 50; 25; 20; 15; 10; 7.5; 5.0; 2.5; 1.25 mM) without/with melatonin or 17ß-estradiol. Five experiments were performed with different concentrations of melatonin (5.0; 2.5; 1.25; 1.0; 0.625 mM) and one with 17ß-estradiol (1.0 mM). Malondialdehyde + 4-hydroxyalkenals (MDA + 4-HDA) concentration (LPO index) was measured spectrophotometrically. KIO3 increased LPO with the strongest damaging effect (MDA + 4-HDA level: ≈1.28 nmol/mg protein, p < 0.05) revealed at concentrations of around 15 mM, thus corresponding to physiological iodine concentrations in the thyroid. Melatonin reduced LPO (MDA + 4-HDA levels: from ≈0.97 to ≈0,76 and from ≈0,64 to ≈0,49 nmol/mg protein, p < 0.05) induced by KIO3 at concentrations of 10 mM or 7.5 mM. Conclusion: Melatonin can reduce very strong oxidative damage to membrane lipids caused by KIO3 used in doses resulting in physiological iodine concentrations in the thyroid.


VASA ◽  
2017 ◽  
Vol 46 (4) ◽  
pp. 268-274
Author(s):  
Erhan Saraçoğlu ◽  
Ertan Vuruşkan ◽  
Yusuf Çekici ◽  
Salih Kiliç ◽  
Halil Ay ◽  
...  

Abstract. Background: After carotid artery stenting (CAS), neurological complications that cannot be explained with imaging methods may develop. In our study we aimed to show, using oxidative stress markers, isolated oxidative damage and resulting neurological findings following CAS in patients with asymptomatic carotid artery stenosis. Patients and methods: We included 131 neurologically asymptomatic patients requiring CAS. The neurological findings were evaluated using the modified Rankin Scale (mRS) prior to the procedure, one hour post-procedure, and two days after. Patients with elevated mRS scores but with or without typical hyperintense lesions observed on an MRI and with changes of oxidative stress marker levels at the time (Δtotal-thiol, Δtotal antioxidative status [TAS], and Δtotal oxidant status [TOS]) were evaluated. Results: In the neurological examination carried out one hour prior to the procedure, there were 92 patients with mRS = 0, 20 with mRS = 1, and 12 with mRS = 2. When Δtotal-thiol, ΔTAS, and ΔTOS values and the mRS were compared, it was observed that as the difference in oxidative parameters increased, clinical deterioration also increased proportionally (p = 0.001). Conclusions: We demonstrate a possible correlation between oxidative damage and neurological findings after CAS which could not be explained by routine imaging methods.


Planta Medica ◽  
2014 ◽  
Vol 80 (16) ◽  
Author(s):  
A Adomakp-Bonsu ◽  
M Pratten ◽  
J Fry ◽  
S Chan
Keyword(s):  

2019 ◽  
Vol 2 (2) ◽  
pp. 1-21 ◽  
Author(s):  
Elina Mitra ◽  
Bharati Bhattacharjee ◽  
Palash Kumar Pal ◽  
Arnab Kumar Ghosh ◽  
Sanatan Mishra ◽  
...  

Cadmium (Cd) is a notorious environmental pollutant known for its wide range of toxicities to organisms. Thus, the present study is designed to examine whether melatonin, a potent antioxidant, protects against Cd-induced oxidative damage in the heart, liver and kidney of rats. Cd treatment at a dose of 0.44 mg/kg for 15 days caused severe damage in all these organs. These included significantly increased activities of SGPT, SGOT, lactate dehydrogenase- 1 and 5 and ALP and levels of total lactate, creatinine, lipid peroxidation, protein carbonyl content and reduced glutathione while the activities of superoxide dismutases, catalase, glutathione peroxidase, glutathione reductase and glutathione-S-transferase along with mitochondrial pyruvate dehydrogenase, isocitrate dehydrogenase, α-keto glutarate dehydrogenase, succinate dehydrogenase, NADH-cytochrome-c-oxidoreductase and cytochrome-c-oxidase were significantly reduced by Cd. However, if melatonin was given orally 30 min before Cd injection, all these alterations induced by Cd were significantly preserved by melatonin. Histological observations also demonstrated that Cd exposure caused cellular lesions, promoting necrotic or apoptotic changes. Notably, all these changes were significantly protected by melatonin. The results suggest that melatonin is a beneficial molecule to ameliorate Cd-induced oxidative damage in the heart, liver and kidney tissues of rats with its powerful antioxidant capacity, heavy metal chelating activity and competition of binding sites with Cd to the GSH and catalase.


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