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Discover Nano Jan 2024In this work, iron oxide (FeO) magnetic nanoparticles (MNPs) and graphene oxide (GO) nanosheets were prepared via the co-precipitation technique and the Modified Hummer...
In this work, iron oxide (FeO) magnetic nanoparticles (MNPs) and graphene oxide (GO) nanosheets were prepared via the co-precipitation technique and the Modified Hummer method. FeO MNPs and GO nanosheets were combined to prepare FeO/GO nanocomposite and subsequently conjugated with Digitonin (DIG) in order to obtain a dual-targeted delivery system based on DIG/FeO/GO nanocomposite. SEM images reveal the presence of FeO MNPs at a scale of 100 nm, exhibiting dispersion between the GO nanosheets. Aggregation of the DIG/FeO/GO nanocomposite was observed at various size scales. The XRD structural analysis confirms the crystal structure of the prepared samples. The FeO MNPs demonstrated the main XRD-diffracted peaks. Also, GO nanosheets exhibit crystalline characteristics on the (001) and (002) planes. The predominant peaks observed in the DIG/GO/FeO nanocomposite are attributed to the crystal phases of FeO MNPs. The FT-IR vibrational modes observed in the GO/DIG/FeO nanocomposite indicate the presence of crosslinking between GO nanosheet layers and the FeO MNPs. The antioxidant activity of the prepared samples was measured and the DIG/GO/FeO nanocomposite demonstrated a significantly high antioxidant activity in both 2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino-bis-3-ethylbenzthiazoline-6-sulfonic acid (ABTS) tests.
PubMed: 38253925
DOI: 10.1186/s11671-024-03960-7 -
Plant Science : An International... Nov 2023In vascular plants, the thylakoid architecture is dominated by the highly structured multiple membrane layers known as grana. The structural diversity of the thylakoid...
In vascular plants, the thylakoid architecture is dominated by the highly structured multiple membrane layers known as grana. The structural diversity of the thylakoid system among plant species is mainly determined by the adaptation to the growth light regime, according to a paradigm stating that shade-tolerant species are featured by a high membrane extension with an enhanced number of thylakoid layers per granum. In this study, the thylakoid system was analysed in Selaginella martensii Spring, a shade-adapted rainforest species belonging to lycophytes, a diminutive plant lineage, sister clade of all other vascular plants (euphyllophytes, including ferns and seed plants). The species is characterized by giant cup-shaped chloroplasts in the upper epidermis and, quantitatively less important, disk-shaped chloroplasts in the mesophyll and lower epidermis. The study aimed at the quantitative assessment of the thylakoid appression exploiting a combination of complementary methods, including electron microscopy, selective thylakoid solubilisation, electron paramagnetic resonance, and simultaneous analysis of fast chlorophyll a fluorescence and P700 redox state. With a chlorophyll a/b ratio of 2.6 and PSI/PSII ratio of 0.31, the plant confirmed two typical hallmarks of shade-adaptation. The morphometric analysis of electron micrographs revealed a 33% fraction of non-appressed thylakoid domains. However, contrasting with the structural paradigm of thylakoid shade-adaptation in angiosperms, S. martensii privileges the increase in the granum diameter in place of the increase in the number of layers building the granum. The very wide grana diameter, 727 nm on average, largely overcame the threshold of 500 nm currently hypothesized to allow an effective diffusion of long-range electron carriers. The fraction of non-appressed membranes based on the selective solubilisation of thylakoids with digitonin was 26%, lower than the morphometric determination, indicating the presence of non-appressed domains inaccessible to the detergent, most probably because of the high three-dimensional complexity of the thylakoid system in S. martensii. Particularly, strong irregularity of grana stacks is determined by assembling thylakoid layers of variable width that tend to slide apart from each other as the number of stacked layers increases.
PubMed: 37595894
DOI: 10.1016/j.plantsci.2023.111833 -
Drug Metabolism and Disposition: the... Nov 2023Our recent study revealed that SLC49A4, known as disrupted in renal carcinoma 2, is a H-coupled lysosomal exporter for pyridoxine (vitamin B6), a cationic compound, and...
Our recent study revealed that SLC49A4, known as disrupted in renal carcinoma 2, is a H-coupled lysosomal exporter for pyridoxine (vitamin B6), a cationic compound, and involved in the regulation of its lysosomal and cellular levels. We here examined a possibility that this transporter might also transport cationic amphiphilic drugs (CADs) that are known to undergo lysosomal trapping, using pyrilamine, an H-antagonist, as a model CAD and the COS-7 cell line as a model cell system for transient introduction of human SLC49A4 and a recombinant SLC49A4 protein (SLC49A4-AA), in which the N-terminal dileucine motif involved in lysosomal localization was removed by replacing with dialanine for redirected localization to the plasma membrane. The introduction of SLC49A4 into COS-7 cells induced a significant decrease in the accumulation of pyrilamine in the intracellular compartments in the cells treated with digitonin for permeabilization of plasma membranes, suggesting its operation for lysosomal pyrilamine export. Accordingly, functional analysis using the SLC49A4-AA mutant, which operates for cellular uptake at the plasma membrane, in transiently transfected COS-7 cells demonstrated its H-coupled operation for pyrilamine transport, which was saturable with a Michaelis constant of 132 μM at pH 5.5. In addition, many CADs that may potentially undergo lysosomal trapping, which include imipramine, propranolol, verapamil, and some others, were found to inhibit SLC49A4-AA-mediated pyrilamine transport, suggesting their affinity for SLC49A4. These results suggest that SLC49A4 is involved in the lysosomal trapping of pyrilamine, operating for its exit. The CADs that inhibited SLC49A4-AA-mediated pyrilamine transport could also be SLC49A4 substrate candidates. SLC49A4 mediates the transport of pyrilamine in a H-coupled manner at the lysosomal membrane. This could be a newly identified mechanism for lysosomal export involved in its lysosomal trapping.
PubMed: 37963658
DOI: 10.1124/dmd.123.001354 -
SLAS Discovery : Advancing Life... May 2024We report the development of a 384-well formatted NanoBRET assay to characterize molecular glues of 14-3-3/client interactions in living cells. The seven isoforms of...
We report the development of a 384-well formatted NanoBRET assay to characterize molecular glues of 14-3-3/client interactions in living cells. The seven isoforms of 14-3-3 are dimeric hub proteins with diverse roles including transcription factor regulation and signal transduction. 14-3-3 interacts with hundreds of client proteins to regulate their function and is therefore an ideal therapeutic target when client selectivity can be achieved. We have developed the NanoBRET system for three 14-3-3σ client proteins CRAF, TAZ, and estrogen receptor α (ERα), which represent three specific binding modes. We have measured stabilization of 14-3-3σ/client complexes by molecular glues with EC values between 100 nM and 1 μM in cells, which align with the EC values calculated by fluorescence anisotropy in vitro. Developing this NanoBRET system for the hub protein 14-3-3σ allows for a streamlined approach, bypassing multiple optimization steps in the assay development process for other 14-3-3σ clients. The NanoBRET system allows for an assessment of PPI stabilization in a more physiologically relevant, cell-based environment using full-length proteins. The method is applicable to diverse protein-protein interactions (PPIs) and offers a robust platform to explore libraries of compounds for both PPI stabilizers and inhibitors.
PubMed: 38797286
DOI: 10.1016/j.slasd.2024.100165