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Title: The concentration-dependent aggregation of Ag NPs induced by cystine

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Publication Date:
Sponsoring Org.:
USDOE Office of Environmental Management (EM)
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Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Science of the Total Environment
Additional Journal Information:
Journal Volume: 557-558; Journal Issue: C; Related Information: CHORUS Timestamp: 2017-10-06 15:07:36; Journal ID: ISSN 0048-9697
Country of Publication:

Citation Formats

Afshinnia, K., Gibson, I., Merrifield, R., and Baalousha, M.. The concentration-dependent aggregation of Ag NPs induced by cystine. Netherlands: N. p., 2016. Web. doi:10.1016/j.scitotenv.2016.02.212.
Afshinnia, K., Gibson, I., Merrifield, R., & Baalousha, M.. The concentration-dependent aggregation of Ag NPs induced by cystine. Netherlands. doi:10.1016/j.scitotenv.2016.02.212.
Afshinnia, K., Gibson, I., Merrifield, R., and Baalousha, M.. 2016. "The concentration-dependent aggregation of Ag NPs induced by cystine". Netherlands. doi:10.1016/j.scitotenv.2016.02.212.
title = {The concentration-dependent aggregation of Ag NPs induced by cystine},
author = {Afshinnia, K. and Gibson, I. and Merrifield, R. and Baalousha, M.},
abstractNote = {},
doi = {10.1016/j.scitotenv.2016.02.212},
journal = {Science of the Total Environment},
number = C,
volume = 557-558,
place = {Netherlands},
year = 2016,
month = 7

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.scitotenv.2016.02.212

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Cited by: 4works
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  • Highlights: • We investigated the impact of cyclic nucleotide analogues on platelet activation. • Different time dependence were found for inhibition of platelet activation. • Additive effect was found using PKA- and PKG-activating analogues. • Our results may explain some of the discrepancies reported for cNMP signalling. - Abstract: In platelets, nitric oxide (NO) activates cGMP/PKG signalling, whereas prostaglandins and adenosine signal through cAMP/PKA. Cyclic nucleotide signalling has been considered to play an inhibitory role in platelets. However, an early stimulatory effect of NO and cGMP-PKG signalling in low dose agonist-induced platelet activation have recently been suggested. Here, we investigatedmore » whether different experimental conditions could explain some of the discrepancy reported for platelet cGMP-PKG-signalling. We treated gel-filtered human platelets with cGMP and cAMP analogues, and used flow cytometric assays to detect low dose thrombin-induced formation of small platelet aggregates, single platelet disappearance (SPD), platelet-derived microparticles (PMP) and thrombin receptor agonist peptide (TRAP)-induced P-selectin expression. All four agonist-induced platelet activation phases were blocked when platelets were costimulated with the PKG activators 8-Br-PET-cGMP or 8-pCPT-cGMP and low-doses of thrombin or TRAP. However, extended incubation with 8-Br-PET-cGMP decreased its inhibition of TRAP-induced P-selectin expression in a time-dependent manner. This effect did not involve desensitisation of PKG or PKA activity, measured as site-specific VASP phosphorylation. Moreover, PKG activators in combination with the PKA activator Sp-5,6-DCL-cBIMPS revealed additive inhibitory effect on TRAP-induced P-selectin expression. Taken together, we found no evidence for a stimulatory role of cGMP/PKG in platelets activation and conclude rather that cGMP/PKG signalling has an important inhibitory function in human platelet activation.« less
  • The cells of D. discoideum acquire developmentally regulated cohesive properties during aggregation and fruiting body construction. On the bases of genetic, serological, and physiological evidence, it has been suggested that two distinct cohesive systems operate: an aggregation-related (AR) system that facilitates the formation of multicellular aggregates and post-aggregated-related (PAR) system that maintains the integrity of the aggregate thereafter. We had previously demonstrated that ghosts and membrane fragments retain the cohesive properties of the cell from which they were derived. Here, we describe a two-phase assay involving the Ca/sup 2 +/-dependent binding of /sup 125/I-labeled cell ghosts in suspension to theirmore » unlabeled counterparts immobilized on plastic surfaces. Using this assay we show that the ghosts of newly aggregation-competent (8 h) cells and of cells from the Mexican hat (18 h) stage of fruit construction can bind, each to its immobilized counterpart, but not heterologously. Furthermore, neither binds to the immobilized ghosts of vegetative cells. This provides direct, functional evidence demonstrating the existence of the two stage-specific cohesive systems.« less
  • To elucidate the recently advanced hypothesis that glutathione (L-gamma-glutamyl-L-cysteinyl glycine (GSH)) regulates deiodinating enzyme activities, accounting for the decreased conversion of T4 to T3 in the liver of fetal and starved animals, we investigated thyroid hormone metabolism in GSH-depleted neoplastic and normal hepatocytes. In monkey hepatocarcinoma cells, intracellular total GSH decreased below 10% of the control value (approximately 25 micrograms/mg protein) when cells were grown for 44 h in medium deficient in cystine and methionine or in cystine alone. The latter finding indicated that transsulfuration from methionine to cysteine was defective in these neoplastic cells. In primary cultured adult ratmore » hepatocytes, on the other hand, the transsulfuration pathway was intact, and total GSH decreased below 10% of control (approximately 20 micrograms/mg protein) only in cells grown in cystine- and methionine-deficient medium. In both cell types, the oxidized GSH fraction remained constant (2-5% of total). Incubation with 125I-labeled T4 and T3, followed by chromatography, was used to evaluate 5-deiodination in hepatocarcinoma cells and both 5- and 5'-deiodination in normal hepatocytes. Deiodination was not decreased by GSH deficiency in either case, but was actually increased in hepatocarcinoma cells. This resulted from an increase in the Vmax of 5-deiodinase related to growth arrest. Diamide at 2 mM reversibly inhibited both 5'- and 5'-deiodination in rat hepatocytes, accompanied by decreased total GSH as well as increased GSH disulfide (27% of total). The data suggest that GSH is so abundant in the liver that hepatocytes can tolerate a greater than 90% decrease in intracellular concentration without any change in thyroid hormone deiodination and indicate that altered thyroid hormone metabolism in the fetus and in starvation cannot be accounted for by a decreased hepatic GSH concentration.« less