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| Whitby, Hannah; Hollibaugh, James T.; Van Den Berg, Constant M. G.. |
| The concentrations of dissolved copper (Cu-d), copper-binding ligands, thiourea-type thiols, and humic substances (HScu) were measured in estuarine waters adjacent to Sapelo Island, Georgia, USA, on a monthly basis from April to December 2014. Here we present the seasonal cycle of copper speciation within the estuary and compare it to the development of an annually occurring bloom of Ammonia Oxidizing Archaea (AOA), which require copper for many enzymes. Two types of complexing ligands (L-1 and L-2) were found to dominate with mean complex stabilities (log K'(cuL)) of 14.5 and 12.8. Strong complexation resulted in lowering the concentration of free cupric ion (Cu2+) to femtomolar (fM) levels throughout the study and to sub-fM levels during the summer... |
| Tipo: Text |
Palavras-chave: Copper speciation; Cathodic stripping voltammetry; Humic substances; Thiols; Thiourea; Organic ligands; Thaumarchaeota; Ammonia-oxidizing archaea. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00616/72834/72735.pdf |
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| Di Mascio,P.; Dewez,B.; Garcia,C.R.S.. |
| We have studied the effect of peroxynitrite (ONOO-) on the membrane cytoskeleton of red blood cells and its protection by melatonin. Analysis of the protein fraction of the preparation by SDS-PAGE revealed a dose-dependent (0-600 µM ONOO-) disappearance at pH 7.4 of the main proteins: spectrin, band 3, and actin, with the concomitant formation of high-molecular weight aggregates resistant to reduction by ß-mercaptoethanol (2%) at room temperature for 20 min. These aggregates were not solubilized by 8 M urea. Incubation of the membrane cytoskeleton with ONOO- was characterized by a marked depletion of free sulfhydryl groups (50% at 250 µM ONOO-). However, a lack of effect of ß-mercaptoethanol suggests that, under our conditions, aggregate formation is not... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Peroxynitrite; Melatonin; Spectrin; Protein; Ghost; Thiols. |
| Ano: 2000 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2000000100002 |
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