scholarly journals Toxic effects of chlortetracycline on maize growth, reactive oxygen species generation and the antioxidant response

2012 ◽  
Vol 24 (6) ◽  
pp. 1099-1105 ◽  
Author(s):  
Bei Wen ◽  
Yu Liu ◽  
Peng Wang ◽  
Tong Wu ◽  
Shuzhen Zhang ◽  
...  
2008 ◽  
Vol 54 (12) ◽  
pp. 977-983 ◽  
Author(s):  
Radoslav I. Abrashev ◽  
Svetlana B. Pashova ◽  
Lilyana N. Stefanova ◽  
Spassen V. Vassilev ◽  
Pavlina A. Dolashka-Angelova ◽  
...  

To extend the knowledge about the relationship between heat shock and oxidative stress in lower eukaryotes, the filamentous fungus Aspergillus niger 26 was chosen as a model system. Here, the response of A. niger cells to heat shock is reported. The temperature treatment significantly increased the levels of reactive oxygen species, superoxide anions (O2•–), and hydrogen peroxide and the rate of cyanide-resistant respiration as a marker of oxidative stress. Enhanced reactive oxygen species generation coincided with an increase in the content of oxidative damaged protein and in the accumulation of the storage carbohydrates trehalose and glycogen. Thermal survival of the A. niger cells corresponded to a significant increase in the levels of the antioxidant enzymes superoxide dismutase and catalase for all variants. These observations suggest that heat and oxidative stress have a common cellular effect.


The eff ect of the non-opiate analog of leu-enkephalin (peptide NALE: Phe – D – Ala – Gly – Phe – Leu – Arg) on the reactive oxygen species generation in the heart of albino rats in the early postnatal period was studied. Peptide NALE was administered intraperitoneally in the dose of 100 μ/kg daily from 2 to 6 days of life. Reactive oxygen species generation was assessed by chemiluminescence in the heart homogenates of 7-day-old animals. Decreasing of reactive oxygen species generation nearly by 30 % and an increasing in antioxidant system activity by the 20-27 %, compared with the control parameters, were found. The antioxidant eff ect of peptide NALE is associated with the presence of the amino acid Arg in the structure of the peptide. An analogue of NALE peptide, devoid of Arg (peptide Phe – D – Ala – Gly – Phe – Leu – Gly), had a signifi cant lower antioxidant eff ect. The NO-synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) in the dose 50 mg/kg, administered with NALE peptide, reduced the severity of the NALE antioxidant eff ect. The results of the study suggest that the pronounced antioxidant eff ect of NALE peptide in the heart of albino rats, at least in part, is due to the interaction with the nitric oxide system.


1993 ◽  
Vol 149 (1) ◽  
pp. 64-67 ◽  
Author(s):  
Donald L. Weese ◽  
Michael L. Peaster ◽  
Kyle K. Himsl ◽  
Gary E. Leach ◽  
Pramod M. Lad ◽  
...  

2020 ◽  
Vol 21 (14) ◽  
pp. 4970
Author(s):  
Juan Perdomo ◽  
Carlos Quintana ◽  
Ignacio González ◽  
Inmaculada Hernández ◽  
Sara Rubio ◽  
...  

Melatonin is present in all living organisms where it displays a diversity of physiological functions. Attenuation of melanogenesis by melatonin has been reported in some mammals and also in rodent melanoma cells. However, melatonin may also stimulate melanogenesis in human melanoma cells through mechanisms that have not yet been revealed. Using the human melanoma cells SK-MEL-1 as a model, an increase in both tyrosinase activity and melanin was already observed at 24 h after melatonin treatment with maximal levels of both being detected at 72 h. This effect was associated with the induction in the expression of the enzymes involved in the synthesis of melanin. In this scenario, glycogen synthase kinase-3β seems to play a significant function since melatonin decreased its phosphorylation and preincubation with specific inhibitors of this protein kinase (lithium or BIO) reduced the expression and activity of tyrosinase. Blocking of PI3K/AKT pathway stimulated melanogenesis and the effect was suppressed by the inhibitors of glycogen synthase kinase-3β. Although melatonin is a recognized antioxidant, we found that it stimulates reactive oxygen species generation in SK-MEL-1 cells. These chemical species seem to be an important signal in activating the melanogenic process since the antioxidants N-acetyl-l-cysteine and glutathione decreased both the level and activity of tyrosinase stimulated by melatonin. Our results support the view that regulation of melanogenesis involves a cross-talk between several signaling pathways.


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