In this study, the sorption behavior of six widely used phthalate esters (PEs) on marine sediments was investigated. The adsorption of PEs was fast and reached the equilibrium within 6 h. The forward and backward rate constants of all PEs on sediments were calculated. Several kinds of kinetic and thermodynamic models have been investigated; the pseudo-second-order model and the partition isotherm model were best fitted to the adsorption behavior of PEs. The rate-limiting step of sorption was controlled by the film diffusion mechanism. After treating sediments with HO, the partition coefficients of all PEs were significantly reduced and indicated that the amorphous organic carbon has a major role in adsorption process. The negative values of ΔH° and ΔG° for these compounds showed that the sorption process is exothermic and spontaneous. The adsorption capacities of all PEs were slightly influenced by increasing the salinity from 0 to 40 g L. These research findings have a prime importance on assessment of the fate and transport of PEs in seawater-sediment systems.
α-Crystallin is a protein that is expressed at high levels in all vertebrate eye lenses. It has a molecular weight of 20 kDa and is composed of two subunits: αA and αB. α-Crystallin is a member of the small heat shock protein (sHsps) family that has been shown to prevent protein aggregation. Small molecules are organic compounds that have low molecular weight (<800 Da). Arginin (Arg) is a small molecule and has been shown to prevent protein aggregation through interaction with partially folded intermediates. In this study, the effect of Arg on the chaperone activity of α-crystallin in the presence of dextran, as a crowding agent, against ordered and disordered aggregation of different target proteins (α-lactalbumin, ovotransferrin, and catalase) has been investigated. The experiments were done using visible absorption spectroscopy, ThT-binding assay, fluorescence spectroscopy, and CD spectroscopy. The results showed that in amorphous aggregation and amyloid fibril formation, both in the presence and absence of dextran, Arg had a positive effect on the chaperone action of α-crystallin. However, in the presence of dextran, the effect of Arg on the chaperone ability of α-crystallin was less than in its absence. Thus, our result suggests that crowding interior media decreases the positive effect of Arg on the chaperone ability of α-crystallin. This is a very important issue, since we are trying to find a mechanism to protect living cells against the toxic effect of protein aggregation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.