Treatment of human osteosarcoma cell line MG 63 cells with okadaic acid stimulated phosphorylation of IkappaBalpha, as judged from the results of Western blot analysis and a lambda protein phosphatase dephosphorylation assay. The stimulated phosphorylation of IkappaBalpha was both time- and dose-dependent. The phosphorylation sites of IkappaBalpha were taken to be tyrosine residues because the anti-phospho-tyrosine antibody bound to the samples immunoprecipitated with the anti-IkappaBalpha antibody. In the cells treated with 100 nM okadaic acid consequential translocation of NF-kappaB p65 from the cytosol to the nucleus occurred. Double-stranded RNA-dependent protein kinase (PKR) is a player in the cellular antiviral response and is involved in transcriptional stimulation through activation of NF-kappaB. We investigated the functional relationship between PKR and IkappaBalpha phosphorylation by constructing MG 63 PKR K/R cells that produced a catalytically inactive mutant PKR. NF-kappaB p65 was detected in the nucleus of these cells, even in the unstimulated cells. Although IkappaBalpha was degraded phosphorylation of eIF-2 alpha, a substrate of PKR, did not occur in the mutant cells treated with okadaic acid. Our results suggest that okadaic acid-induced tyrosine phosphorylation of IkappaBalpha was mediated by PKR kinase activity, thus indicating the involvement of this kinase in the control mechanism governing the activation of NF-kappaB.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1007/s11010-005-4440-y | DOI Listing |
Ecotoxicol Environ Saf
January 2025
College of Life Science and Technology, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Jinan University, Guangzhou 510362, China. Electronic address:
Harmful algal blooms (HABs), exacerbated by climate change and environmental disturbances, pose global challenges due to marine toxin contamination, particularly diarrhetic shellfish toxins (DSTs). DSTs are prevalent marine toxins, and understanding their synthesis is vital for managing fisheries and mitigating environmental triggers. This study delves into the synthesis mechanisms of DSTs in Prorocentrum arenarium and Prorocentrum lima, which vary in toxin types and concentrations.
View Article and Find Full Text PDFJ Hazard Mater
December 2024
Center for Marine Studies, Federal University of Paraná, Pontal do Paraná, Brazil.
Microplastics (MP) are suitable substrates for the colonization of harmful microalgal cells and the adsorption of their lipophilic compounds including phycotoxins. Moreover, such interactions likely change as physical-chemical characteristics of the MP surface are gradually modified during plastic degradation in aquatic environments. Using a combination of innovative laboratory experiments, this study systematically investigated, for the first time, the influence of various MP characteristics (polymeric composition, shape, size, and/or surface roughness) on its capacity to carry both living harmful algal cells and dissolved phycotoxins.
View Article and Find Full Text PDFMar Environ Res
December 2024
Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China.
Lipophilic phycotoxins (LPTs) are toxic and lipophilic secondary metabolites produced by toxic microalgae, which pose a serious threat to marine shellfish culture industries. LPTs were systematically investigated in bottom seawater, suspended particulate matter (SPM), sediment, and sediment porewater of Laizhou Bay, a typical mariculture bay in China, to understand the chemical diversity and environment behaviors of LPTs in the benthic environments. Okadaic acid (OA), pectenotoxin-2 (PTX2), dinophysistoxin-1 (DTX1), azaspiracid-2 (AZA2), gymnodimine (GYM), pectenotoxin-2 seco acid (PTX2 SA), 7-epi- pectenotoxin-2 seco acid (7-epi-PTX2 SA), 13-desmethylspirolide C (SPX1), yessotoxin (YTX) and homo YTX (h-YTX) were detected in the benthic environment of Laizhou Bay in spring, indicating that LPTs are rich in chemical diversity.
View Article and Find Full Text PDFHarmful Algae
January 2025
School of Marine and Atmospheric Sciences, Stony Brook University, Southampton, NY, United States. Electronic address:
Pharmaceuticals (Basel)
November 2024
Pharmaceutical and Health Science Department, Pharmacy Faculty, San Pablo-CEU University, CEU Universities, Urbanización Montepríncipe Boadilla del Monte, 28660 Madrid, Spain.
: berries are edible fruits from the Iberian Atlantic coast, characterized by a rich polyphenolic composition, which endows their juice with potential protective effects against neurodegeneration. This study aimed to evaluate the potential of the relatively lesser-known berries as a novel neuroprotective agent against neurodegenerative diseases. : The phenolic compounds of the juice were characterized using UHPLC-HRMS (Orbitrap).
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!